WorldWideScience

Sample records for combined ground-based sensors

  1. Potential use of ground-based sensor technologies for weed detection.

    Science.gov (United States)

    Peteinatos, Gerassimos G; Weis, Martin; Andújar, Dionisio; Rueda Ayala, Victor; Gerhards, Roland

    2014-02-01

    Site-specific weed management is the part of precision agriculture (PA) that tries to effectively control weed infestations with the least economical and environmental burdens. This can be achieved with the aid of ground-based or near-range sensors in combination with decision rules and precise application technologies. Near-range sensor technologies, developed for mounting on a vehicle, have been emerging for PA applications during the last three decades. These technologies focus on identifying plants and measuring their physiological status with the aid of their spectral and morphological characteristics. Cameras, spectrometers, fluorometers and distance sensors are the most prominent sensors for PA applications. The objective of this article is to describe-ground based sensors that have the potential to be used for weed detection and measurement of weed infestation level. An overview of current sensor systems is presented, describing their concepts, results that have been achieved, already utilized commercial systems and problems that persist. A perspective for the development of these sensors is given. © 2013 Society of Chemical Industry.

  2. Ground-based transmission line conductor motion sensor

    International Nuclear Information System (INIS)

    Jacobs, M.L.; Milano, U.

    1988-01-01

    A ground-based-conductor motion-sensing apparatus is provided for remotely sensing movement of electric-power transmission lines, particularly as would occur during the wind-induced condition known as galloping. The apparatus is comprised of a motion sensor and signal-generating means which are placed underneath a transmission line and will sense changes in the electric field around the line due to excessive line motion. The detector then signals a remote station when a conditioning of galloping is sensed. The apparatus of the present invention is advantageous over the line-mounted sensors of the prior art in that it is easier and less hazardous to install. The system can also be modified so that a signal will only be given when particular conditions, such as specific temperature range, large-amplitude line motion, or excessive duration of the line motion, are occurring

  3. Simulation of olive grove gross primary production by the combination of ground and multi-sensor satellite data

    Science.gov (United States)

    Brilli, L.; Chiesi, M.; Maselli, F.; Moriondo, M.; Gioli, B.; Toscano, P.; Zaldei, A.; Bindi, M.

    2013-08-01

    We developed and tested a methodology to estimate olive (Olea europaea L.) gross primary production (GPP) combining ground and multi-sensor satellite data. An eddy-covariance station placed in an olive grove in central Italy provided carbon and water fluxes over two years (2010-2011), which were used as reference to evaluate the performance of a GPP estimation methodology based on a Monteith type model (modified C-Fix) and driven by meteorological and satellite (NDVI) data. A major issue was related to the consideration of the two main olive grove components, i.e. olive trees and inter-tree ground vegetation: this issue was addressed by the separate simulation of carbon fluxes within the two ecosystem layers, followed by their recombination. In this way the eddy covariance GPP measurements were successfully reproduced, with the exception of two periods that followed tillage operations. For these periods measured GPP could be approximated by considering synthetic NDVI values which simulated the expected response of inter-tree ground vegetation to tillages.

  4. Artillery localization using networked wireless ground sensors

    Science.gov (United States)

    Swanson, David C.

    2002-08-01

    This paper presents the results of an installation of four acoustic/seismic ground sensors built using COTS computers and networking gear and operating on a continuous basis at Yuma Proving Grounds, Arizona. A description of the design can be found as well, which is essentially a Windows 2000 PC with 24-bit data acquisition, GPS timing, and environmental sensors for wind and temperature. A 4-element square acoustic array 1.8m on a side can be used to detect the time and angle of arrival of the muzzle blast and the impact explosion. A 3-component geophone allows the seismic wave direction to be estimated. The 8th channel of the 24-bit data acquisition system has a 1-pulse-per-second time signal from the GPS. This allows acoustic/seismic 'snapshots' to be coherently related from multiple disconnected ground sensor nodes. COTS 2.4 GHz frequency hopping radios (802.11 standard) are used with either omni or yagi antennas depending on the location on the range. Localization of the artillery or impact can be done by using the time and angle of arrival of the waves at 2 or more ground sensor locations. However, this straightforward analysis can be significantly complicated by weather and wind noise and is also the subject of another research contract. This work will present a general description of the COTS ground sensor installation, show example data autonomously collected including agent-based atmospheric data, and share some of the lessons learned from operating a Windows 2000 based system continuously outdoors.

  5. Combine harvester monitor system based on wireless sensor network

    Science.gov (United States)

    A measurement method based on Wireless Sensor Network (WSN) was developed to monitor the working condition of combine harvester for remote application. Three JN5139 modules were chosen for sensor data acquisition and another two as a router and a coordinator, which could create a tree topology netwo...

  6. Ground and river water quality monitoring using a smartphone-based pH sensor

    Directory of Open Access Journals (Sweden)

    Sibasish Dutta

    2015-05-01

    Full Text Available We report here the working of a compact and handheld smartphone-based pH sensor for monitoring of ground and river water quality. Using simple laboratory optical components and the camera of the smartphone, we develop a compact spectrophotometer which is operational in the wavelength range of 400-700 nm and having spectral resolution of 0.305 nm/pixel for our equipment. The sensor measures variations in optical absorption band of pH sensitive dye sample in different pH solutions. The transmission image spectra through a transmission grating gets captured by the smartphone, and subsequently converted into intensity vs. wavelengths. Using the designed sensor, we measure water quality of ground water and river water from different locations in Assam and the results are found to be reliable when compared with the standard spectrophotometer tool. The overall cost involved for development of the sensor is relatively low. We envision that the designed sensing technique could emerge as an inexpensive, compact and portable pH sensor that would be useful for in-field applications.

  7. Development of an optochemical sensor for continuous reversible determination of nitrate in drinking water and ground water

    International Nuclear Information System (INIS)

    Lumpp, R.

    1993-09-01

    An optochemical sensor has been developed for continuous reversible determination of nitrate in drinking water and ground water. The sensor is based on the combination of the anion selective liquid ion exchanger Ni(II[bathophenanthroline] 3 2+ with phenolsulfonephtalein dyes in a polyvinylchloride membrane. (orig.) [de

  8. Mobile Ground-Based Radar Sensor for Localization and Mapping: An Evaluation of two Approaches

    Directory of Open Access Journals (Sweden)

    Damien Vivet

    2013-08-01

    Full Text Available This paper is concerned with robotic applications using a ground-based radar sensor for simultaneous localization and mapping problems. In mobile robotics, radar technology is interesting because of its long range and the robustness of radar waves to atmospheric conditions, making these sensors well-suited for extended outdoor robotic applications. Two localization and mapping approaches using data obtained from a 360° field of view microwave radar sensor are presented and compared. The first method is a trajectory-oriented simultaneous localization and mapping technique, which makes no landmark assumptions and avoids the data association problem. The estimation of the ego-motion makes use of the Fourier-Mellin transform for registering radar images in a sequence, from which the rotation and translation of the sensor motion can be estimated. The second approach uses the consequence of using a rotating range sensor in high speed robotics. In such a situation, movement combinations create distortions in the collected data. Velocimetry is achieved here by explicitly analysing these measurement distortions. As a result, the trajectory of the vehicle and then the radar map of outdoor environments can be obtained. The evaluation of experimental results obtained by the two methods is presented on real-world data from a vehicle moving at 30 km/h over a 2.5 km course.

  9. Forecasting Global Horizontal Irradiance Using the LETKF and a Combination of Advected Satellite Images and Sparse Ground Sensors

    Science.gov (United States)

    Harty, T. M.; Lorenzo, A.; Holmgren, W.; Morzfeld, M.

    2017-12-01

    The irradiance incident on a solar panel is the main factor in determining the power output of that panel. For this reason, accurate global horizontal irradiance (GHI) estimates and forecasts are critical when determining the optimal location for a solar power plant, forecasting utility scale solar power production, or forecasting distributed, behind the meter rooftop solar power production. Satellite images provide a basis for producing the GHI estimates needed to undertake these objectives. The focus of this work is to combine satellite derived GHI estimates with ground sensor measurements and an advection model. The idea is to use accurate but sparsely distributed ground sensors to improve satellite derived GHI estimates which can cover large areas (the size of a city or a region of the United States). We use a Bayesian framework to perform the data assimilation, which enables us to produce irradiance forecasts and associated uncertainties which incorporate both satellite and ground sensor data. Within this framework, we utilize satellite images taken from the GOES-15 geostationary satellite (available every 15-30 minutes) as well as ground data taken from irradiance sensors and rooftop solar arrays (available every 5 minutes). The advection model, driven by wind forecasts from a numerical weather model, simulates cloud motion between measurements. We use the Local Ensemble Transform Kalman Filter (LETKF) to perform the data assimilation. We present preliminary results towards making such a system useful in an operational context. We explain how localization and inflation in the LETKF, perturbations of wind-fields, and random perturbations of the advection model, affect the accuracy of our estimates and forecasts. We present experiments showing the accuracy of our forecasted GHI over forecast-horizons of 15 mins to 1 hr. The limitations of our approach and future improvements are also discussed.

  10. Toward High Altitude Airship Ground-Based Boresight Calibration of Hyperspectral Pushbroom Imaging Sensors

    Directory of Open Access Journals (Sweden)

    Aiwu Zhang

    2015-12-01

    Full Text Available The complexity of the single linear hyperspectral pushbroom imaging based on a high altitude airship (HAA without a three-axis stabilized platform is much more than that based on the spaceborne and airborne. Due to the effects of air pressure, temperature and airflow, the large pitch and roll angles tend to appear frequently that create pushbroom images highly characterized with severe geometric distortions. Thus, the in-flight calibration procedure is not appropriate to apply to the single linear pushbroom sensors on HAA having no three-axis stabilized platform. In order to address this problem, a new ground-based boresight calibration method is proposed. Firstly, a coordinate’s transformation model is developed for direct georeferencing (DG of the linear imaging sensor, and then the linear error equation is derived from it by using the Taylor expansion formula. Secondly, the boresight misalignments are worked out by using iterative least squares method with few ground control points (GCPs and ground-based side-scanning experiments. The proposed method is demonstrated by three sets of experiments: (i the stability and reliability of the method is verified through simulation-based experiments; (ii the boresight calibration is performed using ground-based experiments; and (iii the validation is done by applying on the orthorectification of the real hyperspectral pushbroom images from a HAA Earth observation payload system developed by our research team—“LanTianHao”. The test results show that the proposed boresight calibration approach significantly improves the quality of georeferencing by reducing the geometric distortions caused by boresight misalignments to the minimum level.

  11. Satellite and ground-based sensors for the Urban Heat Island analysis in the city of Rome

    DEFF Research Database (Denmark)

    Fabrizi, Roberto; Bonafoni, Stefania; Biondi, Riccardo

    2010-01-01

    In this work, the trend of the Urban Heat Island (UHI) of Rome is analyzed by both ground-based weather stations and a satellite-based infrared sensor. First, we have developed a suitable algorithm employing satellite brightness temperatures for the estimation of the air temperature belonging...... and nighttime scenes taken between 2003 and 2006 have been processed. Analysis of the Canopy Layer Heat Island (CLHI) during summer months reveals a mean growth in magnitude of 3-4 K during nighttime and a negative or almost zero CLHI intensity during daytime, confirmed by the weather stations. © 2010...... by the authors; licensee MDPI, Basel, Switzerland. Keyword: Thermal pollution,Summer months,Advanced-along track scanning radiometers,Urban heat island,Remote sensing,Canopy layer,Atmospheric temperature,Ground based sensors,Weather information services,Satellite remote sensing,Infra-red sensor,Weather stations...

  12. Combined Differential and Static Pressure Sensor based on a Double-Bridged Structure

    DEFF Research Database (Denmark)

    Pedersen, Casper; Jespersen, S.T.; Krog, J.P.

    2005-01-01

    A combined differential and static silicon microelectromechanical system pressure sensor based on a double piezoresistive Wheatstone bridge structure is presented. The developed sensor has a conventional (inner) bridge on a micromachined diaphragm and a secondary (outer) bridge on the chip...... substrate. A novel approach is demonstrated with a combined measurement of outputs from the two bridges, which results in a combined deduction of both differential and static media pressure. Also following this new approach, a significant improvement in differential pressure sensor accuracy is achieved....... Output from the two bridges depends linearly on both differential and absolute (relative to atmospheric pressure) media pressure. Furthermore, the sensor stress distributions involved are studied by three-dimensional finite-element (FE) stress analysis. Furthermore, the FE analysis evaluates current...

  13. Nighttime Aerosol Optical Depth Measurements Using a Ground-based Lunar Photometer

    Science.gov (United States)

    Berkoff, Tim; Omar, Ali; Haggard, Charles; Pippin, Margaret; Tasaddaq, Aasam; Stone, Tom; Rodriguez, Jon; Slutsker, Ilya; Eck, Tom; Holben, Brent; hide

    2015-01-01

    In recent years it was proposed to combine AERONET network photometer capabilities with a high precision lunar model used for satellite calibration to retrieve columnar nighttime AODs. The USGS lunar model can continuously provide pre-atmosphere high precision lunar irradiance determinations for multiple wavelengths at ground sensor locations. When combined with measured irradiances from a ground-based AERONET photometer, atmospheric column transmissions can determined yielding nighttime column aerosol AOD and Angstrom coefficients. Additional demonstrations have utilized this approach to further develop calibration methods and to obtain data in polar regions where extended periods of darkness occur. This new capability enables more complete studies of the diurnal behavior of aerosols, and feedback for models and satellite retrievals for the nighttime behavior of aerosols. It is anticipated that the nighttime capability of these sensors will be useful for comparisons with satellite lidars such as CALIOP and CATS in additional to ground-based lidars in MPLNET at night, when the signal-to-noise ratio is higher than daytime and more precise AOD comparisons can be made.

  14. Geospace Science from Ground-based Magnetometer Arrays: Advances in Sensors, Data Collection, and Data Integration

    Science.gov (United States)

    Mann, Ian; Chi, Peter

    2016-07-01

    Networks of ground-based magnetometers now provide the basis for the diagnosis of magnetic disturbances associated with solar wind-magnetosphere-ionosphere coupling on a truly global scale. Advances in sensor and digitisation technologies offer increases in sensitivity in fluxgate, induction coil, and new micro-sensor technologies - including the promise of hybrid sensors. Similarly, advances in remote connectivity provide the capacity for truly real-time monitoring of global dynamics at cadences sufficient for monitoring and in many cases resolving system level spatio-temporal ambiguities especially in combination with conjugate satellite measurements. A wide variety of the plasmaphysical processes active in driving geospace dynamics can be monitored based on the response of the electrical current system, including those associated with changes in global convection, magnetospheric substorms and nightside tail flows, as well as due to solar wind changes in both dynamic pressure and in response to rotations of the direction of the IMF. Significantly, any changes to the dynamical system must be communicated by the propagation of long-period Alfven and/or compressional waves. These wave populations hence provide diagnostics for not only the energy transport by the wave fields themselves, but also provide a mechanism for diagnosing the structure of the background plasma medium through which the waves propagate. Ultra-low frequency (ULF) waves are especially significant in offering a monitor for mass density profiles, often invisible to particle detectors because of their very low energy, through the application of a variety of magneto-seismology and cross-phase techniques. Renewed scientific interest in the plasma waves associated with near-Earth substorm dynamics, including magnetosphere-ionosphere coupling at substorm onset and their relation to magnetotail flows, as well the importance of global scale ultra-low frequency waves for the energisation, transport

  15. Spatio-temporal monitoring of cotton cultivation using ground-based and airborne multispectral sensors in GIS environment.

    Science.gov (United States)

    Papadopoulos, Antonis; Kalivas, Dionissios; Theocharopoulos, Sid

    2017-07-01

    Multispectral sensor capability of capturing reflectance data at several spectral channels, together with the inherent reflectance responses of various soils and especially plant surfaces, has gained major interest in crop production. In present study, two multispectral sensing systems, a ground-based and an aerial-based, were applied for the multispatial and temporal monitoring of two cotton fields in central Greece. The ground-based system was Crop Circle ACS-430, while the aerial consisted of a consumer-level quadcopter (Phantom 2) and a modified Hero3+ Black digital camera. The purpose of the research was to monitor crop growth with the two systems and investigate possible interrelations between the derived well-known normalized difference vegetation index (NDVI). Five data collection campaigns were conducted during the cultivation period and concerned scanning soil and plants with the ground-based sensor and taking aerial photographs of the fields with the unmanned aerial system. According to the results, both systems successfully monitored cotton growth stages in terms of space and time. The mean values of NDVI changes through time as retrieved by the ground-based system were satisfactorily modelled by a second-order polynomial equation (R 2 0.96 in Field 1 and 0.99 in Field 2). Further, they were highly correlated (r 0.90 in Field 1 and 0.74 in Field 2) with the according values calculated via the aerial-based system. The unmanned aerial system (UAS) can potentially substitute crop scouting as it concerns a time-effective, non-destructive and reliable way of soil and plant monitoring.

  16. The Combination of Micro Diaphragm Pumps and Flow Sensors for Single Stroke Based Liquid Flow Control.

    Science.gov (United States)

    Jenke, Christoph; Pallejà Rubio, Jaume; Kibler, Sebastian; Häfner, Johannes; Richter, Martin; Kutter, Christoph

    2017-04-03

    With the combination of micropumps and flow sensors, highly accurate and secure closed-loop controlled micro dosing systems for liquids are possible. Implementing a single stroke based control mode with piezoelectrically driven micro diaphragm pumps can provide a solution for dosing of volumes down to nanoliters or variable average flow rates in the range of nL/min to μL/min. However, sensor technologies feature a yet undetermined accuracy for measuring highly pulsatile micropump flow. Two miniaturizable in-line sensor types providing electrical readout-differential pressure based flow sensors and thermal calorimetric flow sensors-are evaluated for their suitability of combining them with mircopumps. Single stroke based calibration of the sensors was carried out with a new method, comparing displacement volumes and sensor flow volumes. Limitations of accuracy and performance for single stroke based flow control are described. Results showed that besides particle robustness of sensors, controlling resistive and capacitive damping are key aspects for setting up reproducible and reliable liquid dosing systems. Depending on the required average flow or defined volume, dosing systems with an accuracy of better than 5% for the differential pressure based sensor and better than 6.5% for the thermal calorimeter were achieved.

  17. A transit timing analysis with combined ground- and space-based photometry

    Directory of Open Access Journals (Sweden)

    Raetz St.

    2015-01-01

    The CoRoT satellite looks back on six years of high precision photometry of a very high number of stars. Thousands of transiting events are detected from which 27 were confirmed to be transiting planets so far. In my research I search and analyze TTVs in the CoRoT sample and combine the unprecedented precision of the light curves with ground-based follow-up photometry. Because CoRoT can observe transiting planets only for a maximum duration of 150 days the ground-based follow-up can help to refine the ephemeris. Here we present first examples.

  18. A fiber Bragg grating acceleration sensor for ground surveillance

    Science.gov (United States)

    Jiang, Shaodong; Zhang, Faxiang; Lv, Jingsheng; Ni, Jiasheng; Wang, Chang

    2017-10-01

    Ground surveillance system is a kind of intelligent monitoring equipment for detecting and tracking the ground target. This paper presents a fiber Bragg grating (FBG) acceleration sensor for ground surveillance, which has the characteristics of no power supply, anti-electromagnetic interference, easy large-scale networking, and small size. Which make it able to achieve the advantage of the ground surveillance system while avoiding the shortcoming of the electric sensing. The sensor has a double cantilever beam structure with a sensitivity of 1000 pm/g. Field experiment has been carried out on a flood beach to examine the sensor performance. The result shows that the detection distance on the walking of personnel reaches 70m, and the detection distance on the ordinary motor vehicle reaches 200m. The performance of the FBG sensor can satisfy the actual needs of the ground surveillance system.

  19. The Combination of Micro Diaphragm Pumps and Flow Sensors for Single Stroke Based Liquid Flow Control

    Directory of Open Access Journals (Sweden)

    Christoph Jenke

    2017-04-01

    Full Text Available With the combination of micropumps and flow sensors, highly accurate and secure closed-loop controlled micro dosing systems for liquids are possible. Implementing a single stroke based control mode with piezoelectrically driven micro diaphragm pumps can provide a solution for dosing of volumes down to nanoliters or variable average flow rates in the range of nL/min to μL/min. However, sensor technologies feature a yet undetermined accuracy for measuring highly pulsatile micropump flow. Two miniaturizable in-line sensor types providing electrical readout—differential pressure based flow sensors and thermal calorimetric flow sensors—are evaluated for their suitability of combining them with mircopumps. Single stroke based calibration of the sensors was carried out with a new method, comparing displacement volumes and sensor flow volumes. Limitations of accuracy and performance for single stroke based flow control are described. Results showed that besides particle robustness of sensors, controlling resistive and capacitive damping are key aspects for setting up reproducible and reliable liquid dosing systems. Depending on the required average flow or defined volume, dosing systems with an accuracy of better than 5% for the differential pressure based sensor and better than 6.5% for the thermal calorimeter were achieved.

  20. Evaluation of event-based algorithms for optical flow with ground-truth from inertial measurement sensor

    Directory of Open Access Journals (Sweden)

    Bodo eRückauer

    2016-04-01

    Full Text Available In this study we compare nine optical flow algorithms that locally measure the flow normal to edges according to accuracy and computation cost. In contrast to conventional, frame-based motion flow algorithms, our open-source implementations compute optical flow based on address-events from a neuromorphic Dynamic Vision Sensor (DVS. For this benchmarking we created a dataset of two synthesized and three real samples recorded from a 240x180 pixel Dynamic and Active-pixel Vision Sensor (DAVIS. This dataset contains events from the DVS as well as conventional frames to support testing state-of-the-art frame-based methods. We introduce a new source for the ground truth: In the special case that the perceived motion stems solely from a rotation of the vision sensor around its three camera axes, the true optical flow can be estimated using gyro data from the inertial measurement unit integrated with the DAVIS camera. This provides a ground-truth to which we can compare algorithms that measure optical flow by means of motion cues. An analysis of error sources led to the use of a refractory period, more accurate numerical derivatives and a Savitzky-Golay filter to achieve significant improvements in accuracy. Our pure Java implementations of two recently published algorithms reduce computational cost by up to 29% compared to the original implementations. Two of the algorithms introduced in this paper further speed up processing by a factor of 10 compared with the original implementations, at equal or better accuracy. On a desktop PC, they run in real-time on dense natural input recorded by a DAVIS camera.

  1. Tracking and Interception of Ground-Based RF Sources Using Autonomous Guided Munitions with Passive Bearings-Only Sensors and Tracking Algorithms

    National Research Council Canada - National Science Library

    Ezal, Kenan; Agate, Craig

    2006-01-01

    This paper considers the problem of tracking and intercepting a potentially moving ground-based RF source with an autonomous guided munition that has a passive bearings-only sensor located on its nose...

  2. Event-Based Color Segmentation With a High Dynamic Range Sensor

    Directory of Open Access Journals (Sweden)

    Alexandre Marcireau

    2018-04-01

    Full Text Available This paper introduces a color asynchronous neuromorphic event-based camera and a methodology to process color output from the device to perform color segmentation and tracking at the native temporal resolution of the sensor (down to one microsecond. Our color vision sensor prototype is a combination of three Asynchronous Time-based Image Sensors, sensitive to absolute color information. We devise a color processing algorithm leveraging this information. It is designed to be computationally cheap, thus showing how low level processing benefits from asynchronous acquisition and high temporal resolution data. The resulting color segmentation and tracking performance is assessed both with an indoor controlled scene and two outdoor uncontrolled scenes. The tracking's mean error to the ground truth for the objects of the outdoor scenes ranges from two to twenty pixels.

  3. The Rover Environmental Monitoring Station Ground Temperature Sensor: A Pyrometer for Measuring Ground Temperature on Mars

    Directory of Open Access Journals (Sweden)

    Miguel Ramos

    2010-10-01

    Full Text Available We describe the parameters that drive the design and modeling of the Rover Environmental Monitoring Station (REMS Ground Temperature Sensor (GTS, an instrument aboard NASA’s Mars Science Laboratory, and report preliminary test results. REMS GTS is a lightweight, low-power, and low cost pyrometer for measuring the Martian surface kinematic temperature. The sensor’s main feature is its innovative design, based on a simple mechanical structure with no moving parts. It includes an in-flight calibration system that permits sensor recalibration when sensor sensitivity has been degraded by deposition of dust over the optics. This paper provides the first results of a GTS engineering model working in a Martian-like, extreme environment.

  4. Ground-Based Global Navigation Satellite System Combined Broadcast Ephemeris Data (daily files) from NASA CDDIS

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset consists of ground-based Global Navigation Satellite System (GNSS) Combined Broadcast Ephemeris Data (daily files of all distinct navigation messages...

  5. Design and performance of an integrated ground and space sensor web for monitoring active volcanoes.

    Science.gov (United States)

    Lahusen, Richard; Song, Wenzhan; Kedar, Sharon; Shirazi, Behrooz; Chien, Steve; Doubleday, Joshua; Davies, Ashley; Webb, Frank; Dzurisin, Dan; Pallister, John

    2010-05-01

    An interdisciplinary team of computer, earth and space scientists collaborated to develop a sensor web system for rapid deployment at active volcanoes. The primary goals of this Optimized Autonomous Space In situ Sensorweb (OASIS) are to: 1) integrate complementary space and in situ (ground-based) elements into an interactive, autonomous sensor web; 2) advance sensor web power and communication resource management technology; and 3) enable scalability for seamless addition sensors and other satellites into the sensor web. This three-year project began with a rigorous multidisciplinary interchange that resulted in definition of system requirements to guide the design of the OASIS network and to achieve the stated project goals. Based on those guidelines, we have developed fully self-contained in situ nodes that integrate GPS, seismic, infrasonic and lightning (ash) detection sensors. The nodes in the wireless sensor network are linked to the ground control center through a mesh network that is highly optimized for remote geophysical monitoring. OASIS also features an autonomous bidirectional interaction between ground nodes and instruments on the EO-1 space platform through continuous analysis and messaging capabilities at the command and control center. Data from both the in situ sensors and satellite-borne hyperspectral imaging sensors stream into a common database for real-time visualization and analysis by earth scientists. We have successfully completed a field deployment of 15 nodes within the crater and on the flanks of Mount St. Helens, Washington. The demonstration that sensor web technology facilitates rapid network deployments and that we can achieve real-time continuous data acquisition. We are now optimizing component performance and improving user interaction for additional deployments at erupting volcanoes in 2010.

  6. Enhanced technologies for unattended ground sensor systems

    Science.gov (United States)

    Hartup, David C.

    2010-04-01

    Progress in several technical areas is being leveraged to advantage in Unattended Ground Sensor (UGS) systems. This paper discusses advanced technologies that are appropriate for use in UGS systems. While some technologies provide evolutionary improvements, other technologies result in revolutionary performance advancements for UGS systems. Some specific technologies discussed include wireless cameras and viewers, commercial PDA-based system programmers and monitors, new materials and techniques for packaging improvements, low power cueing sensor radios, advanced long-haul terrestrial and SATCOM radios, and networked communications. Other technologies covered include advanced target detection algorithms, high pixel count cameras for license plate and facial recognition, small cameras that provide large stand-off distances, video transmissions of target activity instead of still images, sensor fusion algorithms, and control center hardware. The impact of each technology on the overall UGS system architecture is discussed, along with the advantages provided to UGS system users. Areas of analysis include required camera parameters as a function of stand-off distance for license plate and facial recognition applications, power consumption for wireless cameras and viewers, sensor fusion communication requirements, and requirements to practically implement video transmission through UGS systems. Examples of devices that have already been fielded using technology from several of these areas are given.

  7. Kalman Filters in Geotechnical Monitoring of Ground Subsidence Using Data from MEMS Sensors

    Science.gov (United States)

    Li, Cheng; Azzam, Rafig; Fernández-Steeger, Tomás M.

    2016-01-01

    The fast development of wireless sensor networks and MEMS make it possible to set up today real-time wireless geotechnical monitoring. To handle interferences and noises from the output data, Kalman filter can be selected as a method to achieve a more realistic estimate of the observations. In this paper, a one-day wireless measurement using accelerometers and inclinometers was deployed on top of a tunnel section under construction in order to monitor ground subsidence. The normal vectors of the sensors were firstly obtained with the help of rotation matrices, and then be projected to the plane of longitudinal section, by which the dip angles over time would be obtained via a trigonometric function. Finally, a centralized Kalman filter was applied to estimate the tilt angles of the sensor nodes based on the data from the embedded accelerometer and the inclinometer. Comparing the results from two sensor nodes deployed away and on the track respectively, the passing of the tunnel boring machine can be identified from unusual performances. Using this method, the ground settlement due to excavation can be measured and a real-time monitoring of ground subsidence can be realized. PMID:27447630

  8. Kalman Filters in Geotechnical Monitoring of Ground Subsidence Using Data from MEMS Sensors

    Directory of Open Access Journals (Sweden)

    Cheng Li

    2016-07-01

    Full Text Available The fast development of wireless sensor networks and MEMS make it possible to set up today real-time wireless geotechnical monitoring. To handle interferences and noises from the output data, Kalman filter can be selected as a method to achieve a more realistic estimate of the observations. In this paper, a one-day wireless measurement using accelerometers and inclinometers was deployed on top of a tunnel section under construction in order to monitor ground subsidence. The normal vectors of the sensors were firstly obtained with the help of rotation matrices, and then be projected to the plane of longitudinal section, by which the dip angles over time would be obtained via a trigonometric function. Finally, a centralized Kalman filter was applied to estimate the tilt angles of the sensor nodes based on the data from the embedded accelerometer and the inclinometer. Comparing the results from two sensor nodes deployed away and on the track respectively, the passing of the tunnel boring machine can be identified from unusual performances. Using this method, the ground settlement due to excavation can be measured and a real-time monitoring of ground subsidence can be realized.

  9. Kalman Filters in Geotechnical Monitoring of Ground Subsidence Using Data from MEMS Sensors.

    Science.gov (United States)

    Li, Cheng; Azzam, Rafig; Fernández-Steeger, Tomás M

    2016-07-19

    The fast development of wireless sensor networks and MEMS make it possible to set up today real-time wireless geotechnical monitoring. To handle interferences and noises from the output data, Kalman filter can be selected as a method to achieve a more realistic estimate of the observations. In this paper, a one-day wireless measurement using accelerometers and inclinometers was deployed on top of a tunnel section under construction in order to monitor ground subsidence. The normal vectors of the sensors were firstly obtained with the help of rotation matrices, and then be projected to the plane of longitudinal section, by which the dip angles over time would be obtained via a trigonometric function. Finally, a centralized Kalman filter was applied to estimate the tilt angles of the sensor nodes based on the data from the embedded accelerometer and the inclinometer. Comparing the results from two sensor nodes deployed away and on the track respectively, the passing of the tunnel boring machine can be identified from unusual performances. Using this method, the ground settlement due to excavation can be measured and a real-time monitoring of ground subsidence can be realized.

  10. A simple network agreement-based approach for combining evidences in a heterogeneous sensor network

    Directory of Open Access Journals (Sweden)

    Raúl Eusebio-Grande

    2015-12-01

    Full Text Available In this research we investigate how the evidences provided by both static and mobile nodes that are part of a heterogenous sensor network can be combined to have trustworthy results. A solution relying on a network agreement-based approach was implemented and tested.

  11. Evaluation of chemical sensors for in situ ground-water monitoring at the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, E.M.; Hostetler, D.D.

    1989-03-01

    This report documents a preliminary review and evaluation of instrument systems and sensors that may be used to detect ground-water contaminants in situ at the Hanford Site. Three topics are covered in this report: (1) identification of a group of priority contaminants at Hanford that could be monitored in situ, (2) a review of current instrument systems and sensors for environmental monitoring, and (3) an evaluation of instrument systems that could be used to monitor Hanford contaminants. Thirteen priority contaminants were identified in Hanford ground water, including carbon tetrachloride and six related chlorinated hydrocarbons, cyanide, methyl ethyl ketone, chromium (VI), fluoride, nitrate, and uranium. Based on transduction principles, chemical sensors were divided into four classes, ten specific types of instrument systems were considered: fluorescence spectroscopy, surface-enhanced Raman spectroscopy (SERS), spark excitation-fiber optic spectrochemical emission sensor (FOSES), chemical optrodes, stripping voltammetry, catalytic surface-modified ion electrode immunoassay sensors, resistance/capacitance, quartz piezobalance and surface acoustic wave devices. Because the flow of heat is difficult to control, there are currently no environmental chemical sensors based on thermal transduction. The ability of these ten instrument systems to detect the thirteen priority contaminants at the Hanford Site at the required sensitivity was evaluated. In addition, all ten instrument systems were qualitatively evaluated for general selectivity, response time, reliability, and field operability. 45 refs., 23 figs., 7 tabs.

  12. Evaluation of chemical sensors for in situ ground-water monitoring at the Hanford Site

    International Nuclear Information System (INIS)

    Murphy, E.M.; Hostetler, D.D.

    1989-03-01

    This report documents a preliminary review and evaluation of instrument systems and sensors that may be used to detect ground-water contaminants in situ at the Hanford Site. Three topics are covered in this report: (1) identification of a group of priority contaminants at Hanford that could be monitored in situ, (2) a review of current instrument systems and sensors for environmental monitoring, and (3) an evaluation of instrument systems that could be used to monitor Hanford contaminants. Thirteen priority contaminants were identified in Hanford ground water, including carbon tetrachloride and six related chlorinated hydrocarbons, cyanide, methyl ethyl ketone, chromium (VI), fluoride, nitrate, and uranium. Based on transduction principles, chemical sensors were divided into four classes, ten specific types of instrument systems were considered: fluorescence spectroscopy, surface-enhanced Raman spectroscopy (SERS), spark excitation-fiber optic spectrochemical emission sensor (FOSES), chemical optrodes, stripping voltammetry, catalytic surface-modified ion electrode immunoassay sensors, resistance/capacitance, quartz piezobalance and surface acoustic wave devices. Because the flow of heat is difficult to control, there are currently no environmental chemical sensors based on thermal transduction. The ability of these ten instrument systems to detect the thirteen priority contaminants at the Hanford Site at the required sensitivity was evaluated. In addition, all ten instrument systems were qualitatively evaluated for general selectivity, response time, reliability, and field operability. 45 refs., 23 figs., 7 tabs

  13. Challenges in complementing data from ground-based sensors with satellite-derived products to measure ecological changes in relation to climate – lessons from temperate wetland-upland landscapes

    Science.gov (United States)

    Gallant, Alisa L.; Sadinski, Walter J.; Brown, Jesslyn F.; Senay, Gabriel B.; Roth, Mark F.

    2018-01-01

    Assessing climate-related ecological changes across spatiotemporal scales meaningful to resource managers is challenging because no one method reliably produces essential data at both fine and broad scales. We recently confronted such challenges while integrating data from ground- and satellite-based sensors for an assessment of four wetland-rich study areas in the U.S. Midwest. We examined relations between temperature and precipitation and a set of variables measured on the ground at individual wetlands and another set measured via satellite sensors within surrounding 4 km2 landscape blocks. At the block scale, we used evapotranspiration and vegetation greenness as remotely sensed proxies for water availability and to estimate seasonal photosynthetic activity. We used sensors on the ground to coincidentally measure surface-water availability and amphibian calling activity at individual wetlands within blocks. Responses of landscape blocks generally paralleled changes in conditions measured on the ground, but the latter were more dynamic, and changes in ecological conditions on the ground that were critical for biota were not always apparent in measurements of related parameters in blocks. Here, we evaluate the effectiveness of decisions and assumptions we made in applying the remotely sensed data for the assessment and the value of integrating observations across scales, sensors, and disciplines.

  14. Flight Test Result for the Ground-Based Radio Navigation System Sensor with an Unmanned Air Vehicle.

    Science.gov (United States)

    Jang, Jaegyu; Ahn, Woo-Guen; Seo, Seungwoo; Lee, Jang Yong; Park, Jun-Pyo

    2015-11-11

    The Ground-based Radio Navigation System (GRNS) is an alternative/backup navigation system based on time synchronized pseudolites. It has been studied for some years due to the potential vulnerability issue of satellite navigation systems (e.g., GPS or Galileo). In the framework of our study, a periodic pulsed sequence was used instead of the randomized pulse sequence recommended as the RTCM (radio technical commission for maritime services) SC (special committee)-104 pseudolite signal, as a randomized pulse sequence with a long dwell time is not suitable for applications requiring high dynamics. This paper introduces a mathematical model of the post-correlation output in a navigation sensor, showing that the aliasing caused by the additional frequency term of a periodic pulsed signal leads to a false lock (i.e., Doppler frequency bias) during the signal acquisition process or in the carrier tracking loop of the navigation sensor. We suggest algorithms to resolve the frequency false lock issue in this paper, relying on the use of a multi-correlator. A flight test with an unmanned helicopter was conducted to verify the implemented navigation sensor. The results of this analysis show that there were no false locks during the flight test and that outliers stem from bad dilution of precision (DOP) or fluctuations in the received signal quality.

  15. The application of unattended ground sensors to stationary targets

    International Nuclear Information System (INIS)

    Sleefe, G.E.; Peglow, S.; Hamrick, R.

    1997-01-01

    The unattended sensing of stationary (i.e. non-mobile) targets is important in applications ranging from counter-proliferation to law enforcement. With stationary targets, sources of seismic, acoustic, and electro-magnetic emissions can potentially be used to detect, identify, and locate the target. Stationary targets have considerably different sensing requirements than the traditional mobile-target unattended ground sensor applications. This paper presents the novel features and requirements of a system for sensing stationary targets. In particular, issues associated with long-listen time signal processing for signal detection, and array processing techniques for signal localization are presented. Example data and signal processing outputs from a stationary target will be used to illustrate these issues. The impact on sensor, electronic signal processing, battery subsystem, and communication requirements will also be discussed. The paper will conclude with a detailed comparison between mobile-target and stationary-target unattended ground sensor architectures

  16. Validating MODIS and Sentinel-2 NDVI Products at a Temperate Deciduous Forest Site Using Two Independent Ground-Based Sensors.

    Science.gov (United States)

    Lange, Maximilian; Dechant, Benjamin; Rebmann, Corinna; Vohland, Michael; Cuntz, Matthias; Doktor, Daniel

    2017-08-11

    Quantifying the accuracy of remote sensing products is a timely endeavor given the rapid increase in Earth observation missions. A validation site for Sentinel-2 products was hence established in central Germany. Automatic multispectral and hyperspectral sensor systems were installed in parallel with an existing eddy covariance flux tower, providing spectral information of the vegetation present at high temporal resolution. Normalized Difference Vegetation Index (NDVI) values from ground-based hyperspectral and multispectral sensors were compared with NDVI products derived from Sentinel-2A and Moderate-resolution Imaging Spectroradiometer (MODIS). The influence of different spatial and temporal resolutions was assessed. High correlations and similar phenological patterns between in situ and satellite-based NDVI time series demonstrated the reliability of satellite-based phenological metrics. Sentinel-2-derived metrics showed better agreement with in situ measurements than MODIS-derived metrics. Dynamic filtering with the best index slope extraction algorithm was nevertheless beneficial for Sentinel-2 NDVI time series despite the availability of quality information from the atmospheric correction procedure.

  17. Optical stimulator for vision-based sensors

    DEFF Research Database (Denmark)

    Rössler, Dirk; Pedersen, David Arge Klevang; Benn, Mathias

    2014-01-01

    We have developed an optical stimulator system for vision-based sensors. The stimulator is an efficient tool for stimulating a camera during on-ground testing with scenes representative of spacecraft flights. Such scenes include starry sky, planetary objects, and other spacecraft. The optical...

  18. Estimation of combined sewer overflow discharge: a software sensor approach based on local water level measurements.

    Science.gov (United States)

    Ahm, Malte; Thorndahl, Søren; Nielsen, Jesper E; Rasmussen, Michael R

    2016-12-01

    Combined sewer overflow (CSO) structures are constructed to effectively discharge excess water during heavy rainfall, to protect the urban drainage system from hydraulic overload. Consequently, most CSO structures are not constructed according to basic hydraulic principles for ideal measurement weirs. It can, therefore, be a challenge to quantify the discharges from CSOs. Quantification of CSO discharges are important in relation to the increased environmental awareness of the receiving water bodies. Furthermore, CSO discharge quantification is essential for closing the rainfall-runoff mass-balance in combined sewer catchments. A closed mass-balance is an advantage for calibration of all urban drainage models based on mass-balance principles. This study presents three different software sensor concepts based on local water level sensors, which can be used to estimate CSO discharge volumes from hydraulic complex CSO structures. The three concepts were tested and verified under real practical conditions. All three concepts were accurate when compared to electromagnetic flow measurements.

  19. Dynamic tire pressure sensor for measuring ground vibration.

    Science.gov (United States)

    Wang, Qi; McDaniel, James Gregory; Wang, Ming L

    2012-11-07

    This work presents a convenient and non-contact acoustic sensing approach for measuring ground vibration. This approach, which uses an instantaneous dynamic tire pressure sensor (DTPS), possesses the capability to replace the accelerometer or directional microphone currently being used for inspecting pavement conditions. By measuring dynamic pressure changes inside the tire, ground vibration can be amplified and isolated from environmental noise. In this work, verifications of the DTPS concept of sensing inside the tire have been carried out. In addition, comparisons between a DTPS, ground-mounted accelerometer, and directional microphone are made. A data analysis algorithm has been developed and optimized to reconstruct ground acceleration from DTPS data. Numerical and experimental studies of this DTPS reveal a strong potential for measuring ground vibration caused by a moving vehicle. A calibration of transfer function between dynamic tire pressure change and ground acceleration may be needed for different tire system or for more accurate application.

  20. Image-Based Airborne Sensors: A Combined Approach for Spectral Signatures Classification through Deterministic Simulated Annealing

    Science.gov (United States)

    Guijarro, María; Pajares, Gonzalo; Herrera, P. Javier

    2009-01-01

    The increasing technology of high-resolution image airborne sensors, including those on board Unmanned Aerial Vehicles, demands automatic solutions for processing, either on-line or off-line, the huge amountds of image data sensed during the flights. The classification of natural spectral signatures in images is one potential application. The actual tendency in classification is oriented towards the combination of simple classifiers. In this paper we propose a combined strategy based on the Deterministic Simulated Annealing (DSA) framework. The simple classifiers used are the well tested supervised parametric Bayesian estimator and the Fuzzy Clustering. The DSA is an optimization approach, which minimizes an energy function. The main contribution of DSA is its ability to avoid local minima during the optimization process thanks to the annealing scheme. It outperforms simple classifiers used for the combination and some combined strategies, including a scheme based on the fuzzy cognitive maps and an optimization approach based on the Hopfield neural network paradigm. PMID:22399989

  1. Comparing distinct ground-based lightning location networks covering the Netherlands

    Science.gov (United States)

    de Vos, Lotte; Leijnse, Hidde; Schmeits, Maurice; Beekhuis, Hans; Poelman, Dieter; Evers, Läslo; Smets, Pieter

    2015-04-01

    Lightning can be detected using a ground-based sensor network. The Royal Netherlands Meteorological Institute (KNMI) monitors lightning activity in the Netherlands with the so-called FLITS-system; a network combining SAFIR-type sensors. This makes use of Very High Frequency (VHF) as well as Low Frequency (LF) sensors. KNMI has recently decided to replace FLITS by data from a sub-continental network operated by Météorage which makes use of LF sensors only (KNMI Lightning Detection Network, or KLDN). KLDN is compared to the FLITS system, as well as Met Office's long-range Arrival Time Difference (ATDnet), which measures Very Low Frequency (VLF). Special focus lies on the ability to detect Cloud to Ground (CG) and Cloud to Cloud (CC) lightning in the Netherlands. Relative detection efficiency of individual flashes and lightning activity in a more general sense are calculated over a period of almost 5 years. Additionally, the detection efficiency of each system is compared to a ground-truth that is constructed from flashes that are detected by both of the other datasets. Finally, infrasound data is used as a fourth lightning data source for several case studies. Relative performance is found to vary strongly with location and time. As expected, it is found that FLITS detects significantly more CC lightning (because of the strong aptitude of VHF antennas to detect CC), though KLDN and ATDnet detect more CG lightning. We analyze statistics computed over the entire 5-year period, where we look at CG as well as total lightning (CC and CG combined). Statistics that are considered are the Probability of Detection (POD) and the so-called Lightning Activity Detection (LAD). POD is defined as the percentage of reference flashes the system detects compared to the total detections in the reference. LAD is defined as the fraction of system recordings of one or more flashes in predefined area boxes over a certain time period given the fact that the reference detects at least one

  2. Detection of premature browning in ground beef with an integrated optical-fibre based sensor using reflection spectroscopy and fibre Bragg grating technology

    International Nuclear Information System (INIS)

    O'Farrell, M; Sheridan, C; Lewis, E

    2007-01-01

    This paper reports on an optical fibre based sensor system to detect the occurrence of premature browning in ground beef. Premature browning (PMB) occurs when, at a temperature below the pasteurisation temperature of 71 deg. C, there are no traces of pink meat left in the patty. PMB is more frequent if poorer quality beef or beef that has been stored under imperfect conditions. The experimental work pertaining to this paper involved cooking fresh meat and meat that has been stored in a freezer for, 1 week, 1 month and 3 months and recording the reflected spectra and temperature at the core of the product, during the cooking process, in order to develop a classifier based on the spectral response and using a Self-Organising Map (SOM) to classify the patties into one of four categories, based on their colour. Further tests were also carried out on developing an all-optical fibre sensor for measuring both the temperature and colour in a single integrated probe. The integrated probe contains two different sensor concepts, one to monitor temperature, based on Fibre Bragg Grating (FBG) technology and a second for meat quality, based on reflection spectroscopy in the visible wavelength range

  3. Estimation of Vertical Ground Reaction Forces and Sagittal Knee Kinematics During Running Using Three Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Frank J. Wouda

    2018-03-01

    Full Text Available Analysis of running mechanics has traditionally been limited to a gait laboratory using either force plates or an instrumented treadmill in combination with a full-body optical motion capture system. With the introduction of inertial motion capture systems, it becomes possible to measure kinematics in any environment. However, kinetic information could not be provided with such technology. Furthermore, numerous body-worn sensors are required for a full-body motion analysis. The aim of this study is to examine the validity of a method to estimate sagittal knee joint angles and vertical ground reaction forces during running using an ambulatory minimal body-worn sensor setup. Two concatenated artificial neural networks were trained (using data from eight healthy subjects to estimate the kinematics and kinetics of the runners. The first artificial neural network maps the information (orientation and acceleration of three inertial sensors (placed at the lower legs and pelvis to lower-body joint angles. The estimated joint angles in combination with measured vertical accelerations are input to a second artificial neural network that estimates vertical ground reaction forces. To validate our approach, estimated joint angles were compared to both inertial and optical references, while kinetic output was compared to measured vertical ground reaction forces from an instrumented treadmill. Performance was evaluated using two scenarios: training and evaluating on a single subject and training on multiple subjects and evaluating on a different subject. The estimated kinematics and kinetics of most subjects show excellent agreement (ρ>0.99 with the reference, for single subject training. Knee flexion/extension angles are estimated with a mean RMSE <5°. Ground reaction forces are estimated with a mean RMSE < 0.27 BW. Additionaly, peak vertical ground reaction force, loading rate and maximal knee flexion during stance were compared, however, no significant

  4. Assessing the Performance of Sensor Fusion Methods: Application to Magnetic-Inertial-Based Human Body Tracking.

    Science.gov (United States)

    Ligorio, Gabriele; Bergamini, Elena; Pasciuto, Ilaria; Vannozzi, Giuseppe; Cappozzo, Aurelio; Sabatini, Angelo Maria

    2016-01-26

    Information from complementary and redundant sensors are often combined within sensor fusion algorithms to obtain a single accurate observation of the system at hand. However, measurements from each sensor are characterized by uncertainties. When multiple data are fused, it is often unclear how all these uncertainties interact and influence the overall performance of the sensor fusion algorithm. To address this issue, a benchmarking procedure is presented, where simulated and real data are combined in different scenarios in order to quantify how each sensor's uncertainties influence the accuracy of the final result. The proposed procedure was applied to the estimation of the pelvis orientation using a waist-worn magnetic-inertial measurement unit. Ground-truth data were obtained from a stereophotogrammetric system and used to obtain simulated data. Two Kalman-based sensor fusion algorithms were submitted to the proposed benchmarking procedure. For the considered application, gyroscope uncertainties proved to be the main error source in orientation estimation accuracy for both tested algorithms. Moreover, although different performances were obtained using simulated data, these differences became negligible when real data were considered. The outcome of this evaluation may be useful both to improve the design of new sensor fusion methods and to drive the algorithm tuning process.

  5. A pilot project combining multispectral proximal sensors and digital cameras for monitoring tropical pastures

    Science.gov (United States)

    Handcock, Rebecca N.; Gobbett, D. L.; González, Luciano A.; Bishop-Hurley, Greg J.; McGavin, Sharon L.

    2016-08-01

    Timely and accurate monitoring of pasture biomass and ground cover is necessary in livestock production systems to ensure productive and sustainable management. Interest in the use of proximal sensors for monitoring pasture status in grazing systems has increased, since data can be returned in near real time. Proximal sensors have the potential for deployment on large properties where remote sensing may not be suitable due to issues such as spatial scale or cloud cover. There are unresolved challenges in gathering reliable sensor data and in calibrating raw sensor data to values such as pasture biomass or vegetation ground cover, which allow meaningful interpretation of sensor data by livestock producers. Our goal was to assess whether a combination of proximal sensors could be reliably deployed to monitor tropical pasture status in an operational beef production system, as a precursor to designing a full sensor deployment. We use this pilot project to (1) illustrate practical issues around sensor deployment, (2) develop the methods necessary for the quality control of the sensor data, and (3) assess the strength of the relationships between vegetation indices derived from the proximal sensors and field observations across the wet and dry seasons. Proximal sensors were deployed at two sites in a tropical pasture on a beef production property near Townsville, Australia. Each site was monitored by a Skye SKR-four-band multispectral sensor (every 1 min), a digital camera (every 30 min), and a soil moisture sensor (every 1 min), each of which were operated over 18 months. Raw data from each sensor was processed to calculate multispectral vegetation indices. The data capture from the digital cameras was more reliable than the multispectral sensors, which had up to 67 % of data discarded after data cleaning and quality control for technical issues related to the sensor design, as well as environmental issues such as water incursion and insect infestations. We recommend

  6. Design and Evaluation of a Wireless Sensor Network Based Aircraft Strength Testing System

    Science.gov (United States)

    Wu, Jian; Yuan, Shenfang; Zhou, Genyuan; Ji, Sai; Wang, Zilong; Wang, Yang

    2009-01-01

    The verification of aerospace structures, including full-scale fatigue and static test programs, is essential for structure strength design and evaluation. However, the current overall ground strength testing systems employ a large number of wires for communication among sensors and data acquisition facilities. The centralized data processing makes test programs lack efficiency and intelligence. Wireless sensor network (WSN) technology might be expected to address the limitations of cable-based aeronautical ground testing systems. This paper presents a wireless sensor network based aircraft strength testing (AST) system design and its evaluation on a real aircraft specimen. In this paper, a miniature, high-precision, and shock-proof wireless sensor node is designed for multi-channel strain gauge signal conditioning and monitoring. A cluster-star network topology protocol and application layer interface are designed in detail. To verify the functionality of the designed wireless sensor network for strength testing capability, a multi-point WSN based AST system is developed for static testing of a real aircraft undercarriage. Based on the designed wireless sensor nodes, the wireless sensor network is deployed to gather, process, and transmit strain gauge signals and monitor results under different static test loads. This paper shows the efficiency of the wireless sensor network based AST system, compared to a conventional AST system. PMID:22408521

  7. Design and evaluation of a wireless sensor network based aircraft strength testing system.

    Science.gov (United States)

    Wu, Jian; Yuan, Shenfang; Zhou, Genyuan; Ji, Sai; Wang, Zilong; Wang, Yang

    2009-01-01

    The verification of aerospace structures, including full-scale fatigue and static test programs, is essential for structure strength design and evaluation. However, the current overall ground strength testing systems employ a large number of wires for communication among sensors and data acquisition facilities. The centralized data processing makes test programs lack efficiency and intelligence. Wireless sensor network (WSN) technology might be expected to address the limitations of cable-based aeronautical ground testing systems. This paper presents a wireless sensor network based aircraft strength testing (AST) system design and its evaluation on a real aircraft specimen. In this paper, a miniature, high-precision, and shock-proof wireless sensor node is designed for multi-channel strain gauge signal conditioning and monitoring. A cluster-star network topology protocol and application layer interface are designed in detail. To verify the functionality of the designed wireless sensor network for strength testing capability, a multi-point WSN based AST system is developed for static testing of a real aircraft undercarriage. Based on the designed wireless sensor nodes, the wireless sensor network is deployed to gather, process, and transmit strain gauge signals and monitor results under different static test loads. This paper shows the efficiency of the wireless sensor network based AST system, compared to a conventional AST system.

  8. Satellite and Ground-Based Sensors for the Urban Heat Island Analysis in the City of Rome

    Directory of Open Access Journals (Sweden)

    Roberto Fabrizi

    2010-05-01

    Full Text Available In this work, the trend of the Urban Heat Island (UHI of Rome is analyzed by both ground-based weather stations and a satellite-based infrared sensor. First, we have developed a suitable algorithm employing satellite brightness temperatures for the estimation of the air temperature belonging to the layer of air closest to the surface. UHI spatial characteristics have been assessed using air temperatures measured by both weather stations and brightness temperature maps from the Advanced Along Track Scanning Radiometer (AATSR on board ENVISAT polar-orbiting satellite. In total, 634 daytime and nighttime scenes taken between 2003 and 2006 have been processed. Analysis of the Canopy Layer Heat Island (CLHI during summer months reveals a mean growth in magnitude of 3–4 K during nighttime and a negative or almost zero CLHI intensity during daytime, confirmed by the weather stations.

  9. Geocenter variations derived from a combined processing of LEO- and ground-based GPS observations

    Science.gov (United States)

    Männel, Benjamin; Rothacher, Markus

    2017-08-01

    GNSS observations provided by the global tracking network of the International GNSS Service (IGS, Dow et al. in J Geod 83(3):191-198, 2009) play an important role in the realization of a unique terrestrial reference frame that is accurate enough to allow a detailed monitoring of the Earth's system. Combining these ground-based data with GPS observations tracked by high-quality dual-frequency receivers on-board low earth orbiters (LEOs) is a promising way to further improve the realization of the terrestrial reference frame and the estimation of geocenter coordinates, GPS satellite orbits and Earth rotation parameters. To assess the scope of the improvement on the geocenter coordinates, we processed a network of 53 globally distributed and stable IGS stations together with four LEOs (GRACE-A, GRACE-B, OSTM/Jason-2 and GOCE) over a time interval of 3 years (2010-2012). To ensure fully consistent solutions, the zero-difference phase observations of the ground stations and LEOs were processed in a common least-squares adjustment, estimating all the relevant parameters such as GPS and LEO orbits, station coordinates, Earth rotation parameters and geocenter motion. We present the significant impact of the individual LEO and a combination of all four LEOs on the geocenter coordinates. The formal errors are reduced by around 20% due to the inclusion of one LEO into the ground-only solution, while in a solution with four LEOs LEO-specific characteristics are significantly reduced. We compare the derived geocenter coordinates w.r.t. LAGEOS results and external solutions based on GPS and SLR data. We found good agreement in the amplitudes of all components; however, the phases in x- and z-direction do not agree well.

  10. Automatic tracking of wake vortices using ground-wind sensor data

    Science.gov (United States)

    1977-01-03

    Algorithms for automatic tracking of wake vortices using ground-wind anemometer : data are developed. Methods of bad-data suppression, track initiation, and : track termination are included. An effective sensor-failure detection-and identification : ...

  11. Unmanned Ground Vehicle Navigation and Coverage Hole Patching in Wireless Sensor Networks

    Science.gov (United States)

    Zhang, Guyu

    2013-01-01

    This dissertation presents a study of an Unmanned Ground Vehicle (UGV) navigation and coverage hole patching in coordinate-free and localization-free Wireless Sensor Networks (WSNs). Navigation and coverage maintenance are related problems since coverage hole patching requires effective navigation in the sensor network environment. A…

  12. Ground-Based Global Navigation Satellite System GLONASS (GLObal NAvigation Satellite System) Combined Broadcast Ephemeris Data (daily files) from NASA CDDIS

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset consists of ground-based Global Navigation Satellite System (GNSS) GLONASS Combined Broadcast Ephemeris Data (daily files of all distinct navigation...

  13. Magnetic field sensor based on the magnetic-fluid-clad combined with singlemode-multimode-singlemode fiber and large core-offset splicing structure

    Science.gov (United States)

    Lv, Ri-qing; Qian, Jun-kai; Zhao, Yong

    2018-03-01

    A simple, compact optical fiber magnetic field sensor is proposed and experimentally demonstrated in this paper. It is based on the magnetic-fluid-clad combined with singlemode-multimode-singlemode fiber structure and large core-offset splicing structure. It was protected by a section of capillary tube and was sealed by UV glue. A sensing property study of the combined optical fiber structure and the proposed sensor were carried out. The experimental results show that the sensitivity of the refractive index of the optical fiber sensing structure is up to 156.63 nm/RIU and the magnetic field sensitivity of the proposed sensor is up to -97.24 pm/Oe in the range from 72.4 Oe to 297.8 Oe. The proposed sensor has several other advantages, such as simple structure, small size, easy fabrication and low cost.

  14. Report on the Audit of Unattended Ground Sensor Systems

    Science.gov (United States)

    1991-02-26

    This final report on the Audit of Unattended Ground Sensor Systems is for your information and use. Comments on the draft were considered in...preparing the final report and changes have been made where appropriate. We performed the audit from February through August 1990. The objective was to

  15. Adaptive Opportunistic Cooperative Control Mechanism Based on Combination Forecasting and Multilevel Sensing Technology of Sensors for Mobile Internet of Things

    Directory of Open Access Journals (Sweden)

    Yong Jin

    2014-01-01

    Full Text Available In mobile Internet of Things, there are many challenges, including sensing technology of sensors, how and when to join cooperative transmission, and how to select the cooperative sensors. To address these problems, we studied the combination forecasting based on the multilevel sensing technology of sensors, building upon which we proposed the adaptive opportunistic cooperative control mechanism based on the threshold values such as activity probability, distance, transmitting power, and number of relay sensors, in consideration of signal to noise ratio and outage probability. More importantly, the relay sensors would do self-test real time in order to judge whether to join the cooperative transmission, for maintaining the optimal cooperative transmission state with high performance. The mathematical analyses results show that the proposed adaptive opportunistic cooperative control approach could perform better in terms of throughput ratio, packet error rate and delay, and energy efficiency, compared with the direct transmission and opportunistic cooperative approaches.

  16. An In Depth Look at Lightning Trends in Hurricane Harvey using Satellite and Ground-Based Measurements

    Science.gov (United States)

    Ringhausen, J.

    2017-12-01

    This research combines satellite measurements of lightning in Hurricane Harvey with ground-based lightning measurements to get a better sense of the total lightning occurring in the hurricane, both intra-cloud (IC) and cloud-to-ground (CG), and how it relates to the intensification and weakening of the tropical system. Past studies have looked at lightning trends in hurricanes using the space based Lightning Imaging Sensor (LIS) or ground-based lightning detection networks. However, both of these methods have drawbacks. For instance, LIS was in low earth orbit, which limited lightning observations to 90 seconds for a particular point on the ground; hence, continuous lightning coverage of a hurricane was not possible. Ground-based networks can have a decreased detection efficiency, particularly for ICs, over oceans where hurricanes generally intensify. With the launch of the Geostationary Lightning Mapper (GLM) on the GOES-16 satellite, researchers can study total lightning continuously over the lifetime of a tropical cyclone. This study utilizes GLM to investigate total lightning activity in Hurricane Harvey temporally; this is augmented with spatial analysis relative to hurricane structure, similar to previous studies. Further, GLM and ground-based network data are combined using Bayesian techniques in a new manner to leverage the strengths of each detection method. This methodology 1) provides a more complete estimate of lightning activity and 2) enables the derivation of the IC:CG ratio (Z-ratio) throughout the time period of the study. In particular, details of the evolution of the Z-ratio in time and space are presented. In addition, lightning stroke spatiotemporal trends are compared to lightning flash trends. This research represents a new application of lightning data that can be used in future study of tropical cyclone intensification and weakening.

  17. Autonomous Aerial Refueling Ground Test Demonstration—A Sensor-in-the-Loop, Non-Tracking Method

    Directory of Open Access Journals (Sweden)

    Chao-I Chen

    2015-05-01

    Full Text Available An essential capability for an unmanned aerial vehicle (UAV to extend its airborne duration without increasing the size of the aircraft is called the autonomous aerial refueling (AAR. This paper proposes a sensor-in-the-loop, non-tracking method for probe-and-drogue style autonomous aerial refueling tasks by combining sensitivity adjustments of a 3D Flash LIDAR camera with computer vision based image-processing techniques. The method overcomes the inherit ambiguity issues when reconstructing 3D information from traditional 2D images by taking advantage of ready to use 3D point cloud data from the camera, followed by well-established computer vision techniques. These techniques include curve fitting algorithms and outlier removal with the random sample consensus (RANSAC algorithm to reliably estimate the drogue center in 3D space, as well as to establish the relative position between the probe and the drogue. To demonstrate the feasibility of the proposed method on a real system, a ground navigation robot was designed and fabricated. Results presented in the paper show that using images acquired from a 3D Flash LIDAR camera as real time visual feedback, the ground robot is able to track a moving simulated drogue and continuously narrow the gap between the robot and the target autonomously.

  18. Solid state magnetic field sensors for micro unattended ground networks using spin dependent tunneling

    Science.gov (United States)

    Tondra, Mark; Nordman, Catherine A.; Lange, Erik H.; Reed, Daniel; Jander, Albrect; Akou, Seraphin; Daughton, James

    2001-09-01

    Micro Unattended Ground Sensor Networks will likely employ magnetic sensors, primarily for discrimination of objects as opposed to initial detection. These magnetic sensors, then, must fit within very small cost, size, and power budgets to be compatible with the envisioned sensor suites. Also, a high degree of sensitivity is required to minimize the number of sensor cells required to survey a given area in the field. Solid state magnetoresistive sensors, with their low cost, small size, and ease of integration, are excellent candidates for these applications assuming that their power and sensitivity performance are acceptable. SDT devices have been fabricated into prototype magnetic field sensors suitable for use in micro unattended ground sensor networks. They are housed in tiny SOIC 8-pin packages and mounted on a circuit board with required voltage regulation, signal amplification and conditioning, and sensor control and communications functions. The best sensitivity results to date are 289 pT/rt. Hz at 1 Hz, and and 7 pT/rt. Hz at f > 10 kHz. Expected near term improvements in performance would bring these levels to approximately 10 pT/rt Hz at 1 Hz and approximately 1 pT/rt. Hz at > 1 kHz.

  19. Validation of Underwater Sensor Package Using Feature Based SLAM

    Directory of Open Access Journals (Sweden)

    Christopher Cain

    2016-03-01

    Full Text Available Robotic vehicles working in new, unexplored environments must be able to locate themselves in the environment while constructing a picture of the objects in the environment that could act as obstacles that would prevent the vehicles from completing their desired tasks. In enclosed environments, underwater range sensors based off of acoustics suffer performance issues due to reflections. Additionally, their relatively high cost make them less than ideal for usage on low cost vehicles designed to be used underwater. In this paper we propose a sensor package composed of a downward facing camera, which is used to perform feature tracking based visual odometry, and a custom vision-based two dimensional rangefinder that can be used on low cost underwater unmanned vehicles. In order to examine the performance of this sensor package in a SLAM framework, experimental tests are performed using an unmanned ground vehicle and two feature based SLAM algorithms, the extended Kalman filter based approach and the Rao-Blackwellized, particle filter based approach, to validate the sensor package.

  20. Validation of Underwater Sensor Package Using Feature Based SLAM

    Science.gov (United States)

    Cain, Christopher; Leonessa, Alexander

    2016-01-01

    Robotic vehicles working in new, unexplored environments must be able to locate themselves in the environment while constructing a picture of the objects in the environment that could act as obstacles that would prevent the vehicles from completing their desired tasks. In enclosed environments, underwater range sensors based off of acoustics suffer performance issues due to reflections. Additionally, their relatively high cost make them less than ideal for usage on low cost vehicles designed to be used underwater. In this paper we propose a sensor package composed of a downward facing camera, which is used to perform feature tracking based visual odometry, and a custom vision-based two dimensional rangefinder that can be used on low cost underwater unmanned vehicles. In order to examine the performance of this sensor package in a SLAM framework, experimental tests are performed using an unmanned ground vehicle and two feature based SLAM algorithms, the extended Kalman filter based approach and the Rao-Blackwellized, particle filter based approach, to validate the sensor package. PMID:26999142

  1. A 2.5D Map-Based Mobile Robot Localization via Cooperation of Aerial and Ground Robots.

    Science.gov (United States)

    Nam, Tae Hyeon; Shim, Jae Hong; Cho, Young Im

    2017-11-25

    Recently, there has been increasing interest in studying the task coordination of aerial and ground robots. When a robot begins navigation in an unknown area, it has no information about the surrounding environment. Accordingly, for robots to perform tasks based on location information, they need a simultaneous localization and mapping (SLAM) process that uses sensor information to draw a map of the environment, while simultaneously estimating the current location of the robot on the map. This paper aims to present a localization method based in cooperation between aerial and ground robots in an indoor environment. The proposed method allows a ground robot to reach accurate destination by using a 2.5D elevation map built by a low-cost RGB-D (Red Green and Blue-Depth) sensor and 2D Laser sensor attached onto an aerial robot. A 2.5D elevation map is formed by projecting height information of an obstacle using depth information obtained by the RGB-D sensor onto a grid map, which is generated by using the 2D Laser sensor and scan matching. Experimental results demonstrate the effectiveness of the proposed method for its accuracy in location recognition and computing speed.

  2. A 2.5D Map-Based Mobile Robot Localization via Cooperation of Aerial and Ground Robots

    Directory of Open Access Journals (Sweden)

    Tae Hyeon Nam

    2017-11-01

    Full Text Available Recently, there has been increasing interest in studying the task coordination of aerial and ground robots. When a robot begins navigation in an unknown area, it has no information about the surrounding environment. Accordingly, for robots to perform tasks based on location information, they need a simultaneous localization and mapping (SLAM process that uses sensor information to draw a map of the environment, while simultaneously estimating the current location of the robot on the map. This paper aims to present a localization method based in cooperation between aerial and ground robots in an indoor environment. The proposed method allows a ground robot to reach accurate destination by using a 2.5D elevation map built by a low-cost RGB-D (Red Green and Blue-Depth sensor and 2D Laser sensor attached onto an aerial robot. A 2.5D elevation map is formed by projecting height information of an obstacle using depth information obtained by the RGB-D sensor onto a grid map, which is generated by using the 2D Laser sensor and scan matching. Experimental results demonstrate the effectiveness of the proposed method for its accuracy in location recognition and computing speed.

  3. Highly sensitive strain sensors based on fragmentized carbon nanotube/polydimethylsiloxane composites

    Science.gov (United States)

    Gao, Yang; Fang, Xiaoliang; Tan, Jianping; Lu, Ting; Pan, Likun; Xuan, Fuzhen

    2018-06-01

    Wearable strain sensors based on nanomaterial/elastomer composites have potential applications in flexible electronic skin, human motion detection, human–machine interfaces, etc. In this research, a type of high performance strain sensors has been developed using fragmentized carbon nanotube/polydimethylsiloxane (CNT/PDMS) composites. The CNT/PDMS composites were ground into fragments, and a liquid-induced densification method was used to fabricate the strain sensors. The strain sensors showed high sensitivity with gauge factors (GFs) larger than 200 and a broad strain detection range up to 80%, much higher than those strain sensors based on unfragmentized CNT/PDMS composites (GF composite particles during mechanical deformation, which causes significant resistance change in the strain sensors. The strain sensors can differentiate mechanical stimuli and monitor various human body motions, such as bending of the fingers, human breathing, and blood pulsing.

  4. A signal combining technique based on channel shortening for cooperative sensor networks

    KAUST Repository

    Hussain, Syed Imtiaz; Alouini, Mohamed-Slim; Hasna, Mazen Omar

    2010-01-01

    The cooperative relaying process needs proper coordination among the communicating and the relaying nodes. This coordination and the required capabilities may not be available in some wireless systems, e.g. wireless sensor networks where the nodes are equipped with very basic communication hardware. In this paper, we consider a scenario where the source node transmits its signal to the destination through multiple relays in an uncoordinated fashion. The destination can capture the multiple copies of the transmitted signal through a Rake receiver. We analyze a situation where the number of Rake fingers N is less than that of the relaying nodes L. In this case, the receiver can combine N strongest signals out of L. The remaining signals will be lost and act as interference to the desired signal components. To tackle this problem, we develop a novel signal combining technique based on channel shortening. This technique proposes a processing block before the Rake reception which compresses the energy of L signal components over N branches while keeping the noise level at its minimum. The proposed scheme saves the system resources and makes the received signal compatible to the available hardware. Simulation results show that it outperforms the selection combining scheme. ©2010 IEEE.

  5. A signal combining technique based on channel shortening for cooperative sensor networks

    KAUST Repository

    Hussain, Syed Imtiaz

    2010-06-01

    The cooperative relaying process needs proper coordination among the communicating and the relaying nodes. This coordination and the required capabilities may not be available in some wireless systems, e.g. wireless sensor networks where the nodes are equipped with very basic communication hardware. In this paper, we consider a scenario where the source node transmits its signal to the destination through multiple relays in an uncoordinated fashion. The destination can capture the multiple copies of the transmitted signal through a Rake receiver. We analyze a situation where the number of Rake fingers N is less than that of the relaying nodes L. In this case, the receiver can combine N strongest signals out of L. The remaining signals will be lost and act as interference to the desired signal components. To tackle this problem, we develop a novel signal combining technique based on channel shortening. This technique proposes a processing block before the Rake reception which compresses the energy of L signal components over N branches while keeping the noise level at its minimum. The proposed scheme saves the system resources and makes the received signal compatible to the available hardware. Simulation results show that it outperforms the selection combining scheme. ©2010 IEEE.

  6. Highly sensitive strain sensors based on fragmentized carbon nanotube/polydimethylsiloxane composites.

    Science.gov (United States)

    Gao, Yang; Fang, Xiaoliang; Tan, Jianping; Lu, Ting; Pan, Likun; Xuan, Fuzhen

    2018-06-08

    Wearable strain sensors based on nanomaterial/elastomer composites have potential applications in flexible electronic skin, human motion detection, human-machine interfaces, etc. In this research, a type of high performance strain sensors has been developed using fragmentized carbon nanotube/polydimethylsiloxane (CNT/PDMS) composites. The CNT/PDMS composites were ground into fragments, and a liquid-induced densification method was used to fabricate the strain sensors. The strain sensors showed high sensitivity with gauge factors (GFs) larger than 200 and a broad strain detection range up to 80%, much higher than those strain sensors based on unfragmentized CNT/PDMS composites (GF sensors is ascribed to the sliding of individual fragmentized-CNT/PDMS-composite particles during mechanical deformation, which causes significant resistance change in the strain sensors. The strain sensors can differentiate mechanical stimuli and monitor various human body motions, such as bending of the fingers, human breathing, and blood pulsing.

  7. The performance of a piezoelectric-sensor-based SHM system under a combined cryogenic temperature and vibration environment

    International Nuclear Information System (INIS)

    Qing, Xinlin P; Beard, Shawn J; Kumar, Amrita; Sullivan, Kevin; Aguilar, Robert; Merchant, Munir; Taniguchi, Mike

    2008-01-01

    A series of tests have been conducted to determine the survivability and functionality of a piezoelectric-sensor-based active structural health monitoring (SHM) SMART Tape system under the operating conditions of typical liquid rocket engines such as cryogenic temperature and vibration loads. The performance of different piezoelectric sensors and a low temperature adhesive under cryogenic temperature was first investigated. The active SHM system for liquid rocket engines was exposed to flight vibration and shock environments on a simulated large booster LOX-H 2 engine propellant duct conditioned to cryogenic temperatures to evaluate the physical robustness of the built-in sensor network as well as operational survivability and functionality. Test results demonstrated that the developed SMART Tape system can withstand operational levels of vibration and shock energy on a representative rocket engine duct assembly, and is functional under the combined cryogenic temperature and vibration environment

  8. Illumination compensation in ground based hyperspectral imaging

    Science.gov (United States)

    Wendel, Alexander; Underwood, James

    2017-07-01

    applicable not only to robotics or agricultural applications, but most very low altitude or ground based hyperspectral sensors operating with natural light.

  9. Combined shearing interferometer and hartmann wavefront sensor

    International Nuclear Information System (INIS)

    Hutchin, R. A.

    1985-01-01

    A sensitive wavefront sensor combining attributes of both a Hartmann type of wavefront sensor and an AC shearing interferometer type of wavefront sensor. An incident wavefront, the slope of which is to be detected, is focussed to first and second focal points at which first and second diffraction gratings are positioned to shear and modulate the wavefront, which then diverges therefrom. The diffraction patterns of the first and second gratings are positioned substantially orthogonal to each other to shear the wavefront in two directions to produce two dimensional wavefront slope data for the AC shearing interferometer portion of the wavefront sensor. First and second dividing optical systems are positioned in the two diverging wavefronts to divide the sheared wavefront into an array of subapertures and also to focus the wavefront in each subaperture to a focal point. A quadrant detector is provided for each subaperture to detect the position of the focal point therein, which provides a first indication, in the manner of a Hartmann wavefront sensor, of the local wavefront slope in each subaperture. The total radiation in each subaperture, as modulated by the diffraction grating, is also detected by the quadrant detector which produces a modulated output signal representative thereof, the phase of which relative to modulation by the diffraction grating provides a second indication of the local wavefront slope in each subaperture, in the manner of an AC shearing interferometer wavefront sensor. The data from both types of sensors is then combined by long term averaging thereof to provide an extremely sensitive wavefront sensor

  10. A novel chalcone-analogue as an optical sensor based on ground and excited states intramolecular charge transfer: A combined experimental and theoretical study

    International Nuclear Information System (INIS)

    Fayed, Tarek A.

    2006-01-01

    Steady-state absorption and emission spectroscopic techniques as well as semiempirical quantum calculations at the AM1 and ZINDO/S levels have been used to investigate the intramolecular charge transfer (ICT) behaviour of a novel chalcone namely; 1-(2-pyridyl)-5-(4-dimethylaminophenyl)-penta-2,4-diene-1-one, DMAC. The ground state DMAC has a significant ICT character and a great sensitivity to the hydrogen bond donating ability of the medium as reflected from the change of the absorption spectra in pure and mixed organic solvents. On the other hand, its excited singlet state exhibits high ICT characters as manifested by the drastic solvatochromic effects. These results are consistent with the data of charge density calculations in both the ground and excited state, which indicates enhancement of the charge transfer from the dimethyl-amino group to the carbonyl oxygen upon excitation. Also, the dipole moment calculations indicates a highly dipolar excited singlet state (Δμ eg = 15.5 D). The solvent dependence of the fluorescence quantum yield of DMAC was interpreted on the basis of positive and negative solvatokinetic as well as the hydrogen bonding effects. Incorporation of the 2-pyridyl group in the chemical structure of the present DMAC led to design of a potential optical sensor for probing acidity of the medium and metal cations such as Zn 2+ , Cd 2+ and Hg 2+ . This was concluded from the high acidochromic and metallochromic behaviour of DMAC on adding such cations to its acetonitrile solutions

  11. Wi-GIM system: a new wireless sensor network (WSN) for accurate ground instability monitoring

    Science.gov (United States)

    Mucchi, Lorenzo; Trippi, Federico; Schina, Rosa; Fornaciai, Alessandro; Gigli, Giovanni; Nannipieri, Luca; Favalli, Massimiliano; Marturia Alavedra, Jordi; Intrieri, Emanuele; Agostini, Andrea; Carnevale, Ennio; Bertolini, Giovanni; Pizziolo, Marco; Casagli, Nicola

    2016-04-01

    Landslides are among the most serious and common geologic hazards around the world. Their impact on human life is expected to increase in the next future as a consequence of human-induced climate change as well as the population growth in proximity of unstable slopes. Therefore, developing better performing technologies for monitoring landslides and providing local authorities with new instruments able to help them in the decision making process, is becoming more and more important. The recent progresses in Information and Communication Technologies (ICT) allow us to extend the use of wireless technologies in landslide monitoring. In particular, the developments in electronics components have permitted to lower the price of the sensors and, at the same time, to actuate more efficient wireless communications. In this work we present a new wireless sensor network (WSN) system, designed and developed for landslide monitoring in the framework of EU Wireless Sensor Network for Ground Instability Monitoring - Wi-GIM project (LIFE12 ENV/IT/001033). We show the preliminary performance of the Wi-GIM system after the first period of monitoring on the active Roncovetro Landslide and on a large subsiding area in the neighbourhood of Sallent village. The Roncovetro landslide is located in the province of Reggio Emilia (Italy) and moved an inferred volume of about 3 million cubic meters. Sallent village is located at the centre of the Catalan evaporitic basin in Spain. The Wi-GIM WSN monitoring system consists of three levels: 1) Master/Gateway level coordinates the WSN and performs data aggregation and local storage; 2) Master/Server level takes care of acquiring and storing data on a remote server; 3) Nodes level that is based on a mesh of peripheral nodes, each consisting in a sensor board equipped with sensors and wireless module. The nodes are located in the landslide ground perimeter and are able to create an ad-hoc WSN. The location of each sensor on the ground is

  12. Ground Control Point - Wireless System Network for UAV-based environmental monitoring applications

    Science.gov (United States)

    Mejia-Aguilar, Abraham

    2016-04-01

    In recent years, Unmanned Aerial Vehicles (UAV) have seen widespread civil applications including usage for survey and monitoring services in areas such as agriculture, construction and civil engineering, private surveillance and reconnaissance services and cultural heritage management. Most aerial monitoring services require the integration of information acquired during the flight (such as imagery) with ground-based information (such as GPS information or others) for improved ground truth validation. For example, to obtain an accurate 3D and Digital Elevation Model based on aerial imagery, it is necessary to include ground-based information of coordinate points, which are normally acquired with surveying methods based on Global Position Systems (GPS). However, GPS surveys are very time consuming and especially for longer time series of monitoring data repeated GPS surveys are necessary. In order to improve speed of data collection and integration, this work presents an autonomous system based on Waspmote technologies build on single nodes interlinked in a Wireless Sensor Network (WSN) star-topology for ground based information collection and later integration with surveying data obtained by UAV. Nodes are designed to be visible from the air, to resist extreme weather conditions with low-power consumption. Besides, nodes are equipped with GPS as well as Inertial Measurement Unit (IMU), accelerometer, temperature and soil moisture sensors and thus provide significant advantages in a broad range of applications for environmental monitoring. For our purpose, the WSN transmits the environmental data with 3G/GPRS to a database on a regular time basis. This project provides a detailed case study and implementation of a Ground Control Point System Network for UAV-based vegetation monitoring of dry mountain grassland in the Matsch valley, Italy.

  13. Smart Sensor for Online Detection of Multiple-Combined Faults in VSD-Fed Induction Motors

    Science.gov (United States)

    Garcia-Ramirez, Armando G.; Osornio-Rios, Roque A.; Granados-Lieberman, David; Garcia-Perez, Arturo; Romero-Troncoso, Rene J.

    2012-01-01

    Induction motors fed through variable speed drives (VSD) are widely used in different industrial processes. Nowadays, the industry demands the integration of smart sensors to improve the fault detection in order to reduce cost, maintenance and power consumption. Induction motors can develop one or more faults at the same time that can be produce severe damages. The combined fault identification in induction motors is a demanding task, but it has been rarely considered in spite of being a common situation, because it is difficult to identify two or more faults simultaneously. This work presents a smart sensor for online detection of simple and multiple-combined faults in induction motors fed through a VSD in a wide frequency range covering low frequencies from 3 Hz and high frequencies up to 60 Hz based on a primary sensor being a commercially available current clamp or a hall-effect sensor. The proposed smart sensor implements a methodology based on the fast Fourier transform (FFT), RMS calculation and artificial neural networks (ANN), which are processed online using digital hardware signal processing based on field programmable gate array (FPGA).

  14. Optimizing placements of ground-based snow sensors for areal snow cover estimation using a machine-learning algorithm and melt-season snow-LiDAR data

    Science.gov (United States)

    Oroza, C.; Zheng, Z.; Glaser, S. D.; Bales, R. C.; Conklin, M. H.

    2016-12-01

    We present a structured, analytical approach to optimize ground-sensor placements based on time-series remotely sensed (LiDAR) data and machine-learning algorithms. We focused on catchments within the Merced and Tuolumne river basins, covered by the JPL Airborne Snow Observatory LiDAR program. First, we used a Gaussian mixture model to identify representative sensor locations in the space of independent variables for each catchment. Multiple independent variables that govern the distribution of snow depth were used, including elevation, slope, and aspect. Second, we used a Gaussian process to estimate the areal distribution of snow depth from the initial set of measurements. This is a covariance-based model that also estimates the areal distribution of model uncertainty based on the independent variable weights and autocorrelation. The uncertainty raster was used to strategically add sensors to minimize model uncertainty. We assessed the temporal accuracy of the method using LiDAR-derived snow-depth rasters collected in water-year 2014. In each area, optimal sensor placements were determined using the first available snow raster for the year. The accuracy in the remaining LiDAR surveys was compared to 100 configurations of sensors selected at random. We found the accuracy of the model from the proposed placements to be higher and more consistent in each remaining survey than the average random configuration. We found that a relatively small number of sensors can be used to accurately reproduce the spatial patterns of snow depth across the basins, when placed using spatial snow data. Our approach also simplifies sensor placement. At present, field surveys are required to identify representative locations for such networks, a process that is labor intensive and provides limited guarantees on the networks' representation of catchment independent variables.

  15. A Practical Application Combining Wireless Sensor Networks and Internet of Things: Safety Management System for Tower Crane Groups

    Directory of Open Access Journals (Sweden)

    Dexing Zhong

    2014-07-01

    Full Text Available The so-called Internet of Things (IoT has attracted increasing attention in the field of computer and information science. In this paper, a specific application of IoT, named Safety Management System for Tower Crane Groups (SMS-TC, is proposed for use in the construction industry field. The operating status of each tower crane was detected by a set of customized sensors, including horizontal and vertical position sensors for the trolley, angle sensors for the jib and load, tilt and wind speed sensors for the tower body. The sensor data is collected and processed by the Tower Crane Safety Terminal Equipment (TC-STE installed in the driver’s operating room. Wireless communication between each TC-STE and the Local Monitoring Terminal (LMT at the ground worksite were fulfilled through a Zigbee wireless network. LMT can share the status information of the whole group with each TC-STE, while the LMT records the real-time data and reports it to the Remote Supervision Platform (RSP through General Packet Radio Service (GPRS. Based on the global status data of the whole group, an anti-collision algorithm was executed in each TC-STE to ensure the safety of each tower crane during construction. Remote supervision can be fulfilled using our client software installed on a personal computer (PC or smartphone. SMS-TC could be considered as a promising practical application that combines a Wireless Sensor Network with the Internet of Things.

  16. A Practical Application Combining Wireless Sensor Networks and Internet of Things: Safety Management System for Tower Crane Groups

    Science.gov (United States)

    Zhong, Dexing; Lv, Hongqiang; Han, Jiuqiang; Wei, Quanrui

    2014-01-01

    The so-called Internet of Things (IoT) has attracted increasing attention in the field of computer and information science. In this paper, a specific application of IoT, named Safety Management System for Tower Crane Groups (SMS-TC), is proposed for use in the construction industry field. The operating status of each tower crane was detected by a set of customized sensors, including horizontal and vertical position sensors for the trolley, angle sensors for the jib and load, tilt and wind speed sensors for the tower body. The sensor data is collected and processed by the Tower Crane Safety Terminal Equipment (TC-STE) installed in the driver's operating room. Wireless communication between each TC-STE and the Local Monitoring Terminal (LMT) at the ground worksite were fulfilled through a Zigbee wireless network. LMT can share the status information of the whole group with each TC-STE, while the LMT records the real-time data and reports it to the Remote Supervision Platform (RSP) through General Packet Radio Service (GPRS). Based on the global status data of the whole group, an anti-collision algorithm was executed in each TC-STE to ensure the safety of each tower crane during construction. Remote supervision can be fulfilled using our client software installed on a personal computer (PC) or smartphone. SMS-TC could be considered as a promising practical application that combines a Wireless Sensor Network with the Internet of Things. PMID:25196106

  17. A practical application combining wireless sensor networks and Internet of Things: Safety Management System for Tower Crane Groups.

    Science.gov (United States)

    Zhong, Dexing; Lv, Hongqiang; Han, Jiuqiang; Wei, Quanrui

    2014-07-30

    The so-called Internet of Things (IoT) has attracted increasing attention in the field of computer and information science. In this paper, a specific application of IoT, named Safety Management System for Tower Crane Groups (SMS-TC), is proposed for use in the construction industry field. The operating status of each tower crane was detected by a set of customized sensors, including horizontal and vertical position sensors for the trolley, angle sensors for the jib and load, tilt and wind speed sensors for the tower body. The sensor data is collected and processed by the Tower Crane Safety Terminal Equipment (TC-STE) installed in the driver's operating room. Wireless communication between each TC-STE and the Local Monitoring Terminal (LMT) at the ground worksite were fulfilled through a Zigbee wireless network. LMT can share the status information of the whole group with each TC-STE, while the LMT records the real-time data and reports it to the Remote Supervision Platform (RSP) through General Packet Radio Service (GPRS). Based on the global status data of the whole group, an anti-collision algorithm was executed in each TC-STE to ensure the safety of each tower crane during construction. Remote supervision can be fulfilled using our client software installed on a personal computer (PC) or smartphone. SMS-TC could be considered as a promising practical application that combines a Wireless Sensor Network with the Internet of Things.

  18. Vehicle Classification and Speed Estimation Using Combined Passive Infrared/Ultrasonic Sensors

    KAUST Repository

    Odat, Enas M.; Shamma, Jeff S.; Claudel, Christian

    2017-01-01

    In this paper, a new sensing device that can simultaneously monitor traffic congestion and urban flash floods is presented. This sensing device is based on the combination of passive infrared sensors (PIRs) and ultrasonic rangefinder, and is used

  19. Novel rf power sensor based on capacitive MEMS technology

    NARCIS (Netherlands)

    Fernandez, L.J.; Visser, Eelke; Sesé, J.; Jansen, Henricus V.; Wiegerink, Remco J.; Flokstra, Jakob

    2003-01-01

    We present the theory, design, fabrication of and first measurements on a novel power for radio frequency (rf) signals, based on capacitive measurements. The novelty of this sensor is thtat it measures the force that is created between the rf signal and a grounded membrande suspended above the line

  20. Obstacle negotiation control for a mobile robot suspended on overhead ground wires by optoelectronic sensors

    Science.gov (United States)

    Zheng, Li; Yi, Ruan

    2009-11-01

    Power line inspection and maintenance already benefit from developments in mobile robotics. This paper presents mobile robots capable of crossing obstacles on overhead ground wires. A teleoperated robot realizes inspection and maintenance tasks on power transmission line equipment. The inspection robot is driven by 11 motor with two arms, two wheels and two claws. The inspection robot is designed to realize the function of observation, grasp, walk, rolling, turn, rise, and decline. This paper is oriented toward 100% reliable obstacle detection and identification, and sensor fusion to increase the autonomy level. An embedded computer based on PC/104 bus is chosen as the core of control system. Visible light camera and thermal infrared Camera are both installed in a programmable pan-and-tilt camera (PPTC) unit. High-quality visual feedback rapidly becomes crucial for human-in-the-loop control and effective teleoperation. The communication system between the robot and the ground station is based on Mesh wireless networks by 700 MHz bands. An expert system programmed with Visual C++ is developed to implement the automatic control. Optoelectronic laser sensors and laser range scanner were installed in robot for obstacle-navigation control to grasp the overhead ground wires. A novel prototype with careful considerations on mobility was designed to inspect the 500KV power transmission lines. Results of experiments demonstrate that the robot can be applied to execute the navigation and inspection tasks.

  1. Vehicle Classification and Speed Estimation Using Combined Passive Infrared/Ultrasonic Sensors

    KAUST Repository

    Odat, Enas M.

    2017-09-18

    In this paper, a new sensing device that can simultaneously monitor traffic congestion and urban flash floods is presented. This sensing device is based on the combination of passive infrared sensors (PIRs) and ultrasonic rangefinder, and is used for real-time vehicle detection, classification, and speed estimation in the context of wireless sensor networks. This framework relies on dynamic Bayesian Networks to fuse heterogeneous data both spatially and temporally for vehicle detection. To estimate the speed of the incoming vehicles, we first use cross correlation and wavelet transform-based methods to estimate the time delay between the signals of different sensors. We then propose a calibration and self-correction model based on Bayesian Networks to make a joint inference by all sensors about the speed and the length of the detected vehicle. Furthermore, we use the measurements of the ultrasonic and the PIR sensors to perform vehicle classification. Validation data (using an experimental dual infrared and ultrasonic traffic sensor) show a 99% accuracy in vehicle detection, a mean error of 5 kph in vehicle speed estimation, a mean error of 0.7m in vehicle length estimation, and a high accuracy in vehicle classification. Finally, we discuss the computational performance of the algorithm, and show that this framework can be implemented on low-power computational devices within a wireless sensor network setting. Such decentralized processing greatly improves the energy consumption of the system and minimizes bandwidth usage.

  2. Toward Sensor-Based Context Aware Systems

    Directory of Open Access Journals (Sweden)

    Kouhei Takada

    2012-01-01

    Full Text Available This paper proposes a methodology for sensor data interpretation that can combine sensor outputs with contexts represented as sets of annotated business rules. Sensor readings are interpreted to generate events labeled with the appropriate type and level of uncertainty. Then, the appropriate context is selected. Reconciliation of different uncertainty types is achieved by a simple technique that moves uncertainty from events to business rules by generating combs of standard Boolean predicates. Finally, context rules are evaluated together with the events to take a decision. The feasibility of our idea is demonstrated via a case study where a context-reasoning engine has been connected to simulated heartbeat sensors using prerecorded experimental data. We use sensor outputs to identify the proper context of operation of a system and trigger decision-making based on context information.

  3. A low-noise MEMS accelerometer for unattended ground sensor applications

    Science.gov (United States)

    Speller, Kevin E.; Yu, Duli

    2004-09-01

    A low-noise micro-machined servo accelerometer has been developed for use in Unattended Ground Sensors (UGS). Compared to conventional coil-and-magnet based velocity transducers, this Micro-Electro-Mechanical System (MEMS) accelerometer offers several key benefits for battlefield monitoring. Many UGS require a compass to determine deployment orientation with respect to magnetic North. This orientation information is critical for determining the bearing of incoming signals. Conventional sensors with sensing technology based on a permanent magnet can cause interference with a compass when used in close proximity. This problem is solved with a MEMS accelerometer which does not require any magnetic materials. Frequency information below 10 Hz is valuable for identification of signal sources. Conventional seismometers used in UGS are typically limited in frequency response from 20 to 200 Hz. The MEMS accelerometer has a flat frequency response from DC to 5 kHz. The wider spectrum of signals received improves detection, classification and monitoring on the battlefield. The DC-coupled output of the MEMS accelerometer also has the added benefit of providing tilt orientation data for the deployed UGS. Other performance parameters of the MEMS accelerometer that are important to UGS such as size, weight, shock survivability, phase response, distortion, and cross-axis rejection will be discussed. Additionally, field test data from human footsteps recorded with the MEMS accelerometer will be presented.

  4. Simulation of a combined heating, cooling and domestic hot water system based on ground source absorption heat pump

    International Nuclear Information System (INIS)

    Wu, Wei; You, Tian; Wang, Baolong; Shi, Wenxing; Li, Xianting

    2014-01-01

    Highlights: • A combined heating/cooling/DHW system based on GSAHP is proposed in cold regions. • The soil imbalance is effectively reduced and soil temperature can be kept stable. • 20% and 15% of condensation/absorption heat is recovered by GSAHP to produce DHW. • The combined system can improve the primary energy efficiency by 23.6% and 44.4%. - Abstract: The amount of energy used for heating and domestic hot water (DHW) is very high and will keep increasing. The conventional ground source electrical heat pump used in heating-dominated buildings has the problems of thermal imbalance, decrease of soil temperature, and deterioration of heating performance. Ground source absorption heat pump (GSAHP) is advantageous in both imbalance reduction and primary energy efficiency (PEE) improvement; however, the imbalance is still unacceptable in the warmer parts of cold regions. A combined heating/cooling/DHW (HCD) system based on GSAHP is proposed to overcome this problem. The GSAHPs using generator absorber heat exchange (GAX) and single-effect (SE) cycles are simulated to obtain the performance under various working conditions. Different HCD systems in Beijing and Shenyang are simulated comparatively in TRNSYS, based on which the thermal imbalance, soil temperature, heat recovery, and energy efficiency are analyzed. Results show that GSAHP–GAX–HCD is suitable for Beijing and GSAHP–SE–HCD is suitable for Shenyang. The imbalance ratio can be reduced to −14.8% in Beijing and to 6.0% in Shenyang with an annual soil temperature variation of only 0.5 °C and 0.1 °C. Furthermore, about 20% and 15% of the total condensation/absorption heat is recovered to produce DHW, and the PEE can reach 1.516 in Beijing and 1.163 in Shenyang. The combined HCD systems can achieve a PEE improvement of 23.6% and 44.4% compared with the normal heating/cooling systems

  5. A Forest Fire Sensor Web Concept with UAVSAR

    Science.gov (United States)

    Lou, Y.; Chien, S.; Clark, D.; Doubleday, J.; Muellerschoen, R.; Zheng, Y.

    2008-12-01

    We developed a forest fire sensor web concept with a UAVSAR-based smart sensor and onboard automated response capability that will allow us to monitor fire progression based on coarse initial information provided by an external source. This autonomous disturbance detection and monitoring system combines the unique capabilities of imaging radar with high throughput onboard processing technology and onboard automated response capability based on specific science algorithms. In this forest fire sensor web scenario, a fire is initially located by MODIS/RapidFire or a ground-based fire observer. This information is transmitted to the UAVSAR onboard automated response system (CASPER). CASPER generates a flight plan to cover the alerted fire area and executes the flight plan. The onboard processor generates the fuel load map from raw radar data, used with wind and elevation information, predicts the likely fire progression. CASPER then autonomously alters the flight plan to track the fire progression, providing this information to the fire fighting team on the ground. We can also relay the precise fire location to other remote sensing assets with autonomous response capability such as Earth Observation-1 (EO-1)'s hyper-spectral imager to acquire the fire data.

  6. YSZ-based sensor using Cr-Fe-based spinel-oxide electrodes for selective detection of CO.

    Science.gov (United States)

    Anggraini, Sri Ayu; Fujio, Yuki; Ikeda, Hiroshi; Miura, Norio

    2017-08-22

    A selective carbon monoxide (CO) sensor was developed by the use of both of CuCrFeO 4 and CoCrFeO 4 as the sensing electrode (SE) for yttria-stabilized zirconia (YSZ)-based potentiometric sensor. The sensing-characteristic examinations of the YSZ-based sensors using each of spinel oxides as the single-SE sensor showed that CuCrFeO 4 -SE had the ability to detect CO, hydrocarbons and NO x gases, while CoCrFeO 4 -SE was sensitive to hydrocarbons and NO x gases. Thus, when both SEs were paired as a combined-SEs sensor, the resulting sensor could generate a selective response to CO at 450 °C under humid conditions. The sensor was also capable of detecting CO in the concentration range of 20-700 ppm. Its sensing mechanism that was examined via polarization-curve measurements was confirmed to be based on mixed-potential model. The CO response generated by the combined-SEs sensor was unaffected by the change of water vapor concentration in the range of 1.3-11.5 vol% H 2 O. Additionally, the sensing performance was stable during 13 days tested. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. A Method for Improving the Pose Accuracy of a Robot Manipulator Based on Multi-Sensor Combined Measurement and Data Fusion

    Science.gov (United States)

    Liu, Bailing; Zhang, Fumin; Qu, Xinghua

    2015-01-01

    An improvement method for the pose accuracy of a robot manipulator by using a multiple-sensor combination measuring system (MCMS) is presented. It is composed of a visual sensor, an angle sensor and a series robot. The visual sensor is utilized to measure the position of the manipulator in real time, and the angle sensor is rigidly attached to the manipulator to obtain its orientation. Due to the higher accuracy of the multi-sensor, two efficient data fusion approaches, the Kalman filter (KF) and multi-sensor optimal information fusion algorithm (MOIFA), are used to fuse the position and orientation of the manipulator. The simulation and experimental results show that the pose accuracy of the robot manipulator is improved dramatically by 38%∼78% with the multi-sensor data fusion. Comparing with reported pose accuracy improvement methods, the primary advantage of this method is that it does not require the complex solution of the kinematics parameter equations, increase of the motion constraints and the complicated procedures of the traditional vision-based methods. It makes the robot processing more autonomous and accurate. To improve the reliability and accuracy of the pose measurements of MCMS, the visual sensor repeatability is experimentally studied. An optimal range of 1 × 0.8 × 1 ∼ 2 × 0.8 × 1 m in the field of view (FOV) is indicated by the experimental results. PMID:25850067

  8. VCSEL-based sensors for distance and velocity

    Science.gov (United States)

    Moench, Holger; Carpaij, Mark; Gerlach, Philipp; Gronenborn, Stephan; Gudde, Ralph; Hellmig, Jochen; Kolb, Johanna; van der Lee, Alexander

    2016-03-01

    VCSEL based sensors can measure distance and velocity in three dimensional space and are already produced in high quantities for professional and consumer applications. Several physical principles are used: VCSELs are applied as infrared illumination for surveillance cameras. High power arrays combined with imaging optics provide a uniform illumination of scenes up to a distance of several hundred meters. Time-of-flight methods use a pulsed VCSEL as light source, either with strong single pulses at low duty cycle or with pulse trains. Because of the sensitivity to background light and the strong decrease of the signal with distance several Watts of laser power are needed at a distance of up to 100m. VCSEL arrays enable power scaling and can provide very short pulses at higher power density. Applications range from extended functions in a smartphone over industrial sensors up to automotive LIDAR for driver assistance and autonomous driving. Self-mixing interference works with coherent laser photons scattered back into the cavity. It is therefore insensitive to environmental light. The method is used to measure target velocity and distance with very high accuracy at distances up to one meter. Single-mode VCSELs with integrated photodiode and grating stabilized polarization enable very compact and cost effective products. Besides the well know application as computer input device new applications with even higher accuracy or for speed over ground measurement in automobiles and up to 250km/h are investigated. All measurement methods exploit the known VCSEL properties like robustness, stability over temperature and the potential for packages with integrated optics and electronics. This makes VCSEL sensors ideally suited for new mass applications in consumer and automotive markets.

  9. Progress report of FY 1997 activities: The application of Kalman filtering to derive water vapor profiles from combined ground-based sensors: Raman lidar, microwave radiometers, GPS, and radiosondes

    International Nuclear Information System (INIS)

    Edgeworth R. Westwater; Yong Han

    1997-01-01

    Previously, the proposers have delivered to ARM a documented algorithm, that is now applied operationally, and which derives water vapor profiles from combined remote sensor measurements of water vapor radiometers, cloud-base ceilometers, and radio acoustic sounding systems (RASS). With the expanded deployment of a Raman lidar at the CART Central Facility, high quality, high vertical-resolution, water vapor profiles will be provided during nighttime clear conditions, and during clear daytime conditions, to somewhat lower altitudes. The object of this proposal was to use Kalman Filtering, previously applied to the combination of nighttime Raman lidar and microwave radiometer data, to derive high-quality water vapor profiles, during non-precipitating conditions, from data routinely available at the CART site. Input data to the algorithm would include: Raman lidar data, highly quality-controlled data of integrated moisture from microwave radiometers and GPS, RASS, and radiosondes. The algorithm will include recently-developed quality control procedures for radiometers. The focus of this years activities has been on the intercomparison of data obtained during an intensive operating period at the SGP CART site in central Oklahoma

  10. Challenges in combining different data sets during analysis when using grounded theory.

    Science.gov (United States)

    Rintala, Tuula-Maria; Paavilainen, Eija; Astedt-Kurki, Päivi

    2014-05-01

    To describe the challenges in combining two data sets during grounded theory analysis. The use of grounded theory in nursing research is common. It is a suitable method for studying human action and interaction. It is recommended that many alternative sources of data are collected to create as rich a dataset as possible. Data from interviews with people with diabetes (n=19) and their family members (n=19). Combining two data sets. When using grounded theory, there are numerous challenges in collecting and managing data, especially for the novice researcher. One challenge is to combine different data sets during the analysis. There are many methodological textbooks about grounded theory but there is little written in the literature about combining different data sets. Discussion is needed on the management of data and the challenges of grounded theory. This article provides a means for combining different data sets in the grounded theory analysis process.

  11. Modern developments for ground-based monitoring of fire behavior and effects

    Science.gov (United States)

    Colin C. Hardy; Robert Kremens; Matthew B. Dickinson

    2010-01-01

    Advances in electronic technology over the last several decades have been staggering. The cost of electronics continues to decrease while system performance increases seemingly without limit. We have applied modern techniques in sensors, electronics and instrumentation to create a suite of ground based diagnostics that can be used in laboratory (~ 1 m2), field scale...

  12. Artificial intelligence/fuzzy logic method for analysis of combined signals from heavy metal chemical sensors

    International Nuclear Information System (INIS)

    Turek, M.; Heiden, W.; Riesen, A.; Chhabda, T.A.; Schubert, J.; Zander, W.; Krueger, P.; Keusgen, M.; Schoening, M.J.

    2009-01-01

    The cross-sensitivity of chemical sensors for several metal ions resembles in a way the overlapping sensitivity of some biological sensors, like the optical colour receptors of human retinal cone cells. While it is difficult to assign crisp classification values to measurands based on complex overlapping sensory signals, fuzzy logic offers a possibility to mathematically model such systems. Current work goes into the direction of mixed heavy metal solutions and the combination of fuzzy logic with heavy metal-sensitive, silicon-based chemical sensors for training scenarios of arbitrary sensor/probe combinations in terms of an electronic tongue. Heavy metals play an important role in environmental analysis. As trace elements as well as water impurities released from industrial processes they occur in the environment. In this work, the development of a new fuzzy logic method based on potentiometric measurements performed with three different miniaturised chalcogenide glass sensors in different heavy metal solutions will be presented. The critical validation of the developed fuzzy logic program will be demonstrated by means of measurements in unknown single- and multi-component heavy metal solutions. Limitations of this program and a comparison between calculated and expected values in terms of analyte composition and heavy metal ion concentration will be shown and discussed.

  13. Artificial intelligence/fuzzy logic method for analysis of combined signals from heavy metal chemical sensors

    Energy Technology Data Exchange (ETDEWEB)

    Turek, M. [Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, Campus Juelich, Juelich (Germany); Institute of Bio- and Nanosystems (IBN), Research Centre Juelich GmbH, Juelich (Germany); Heiden, W.; Riesen, A. [Bonn-Rhein-Sieg University of Applied Sciences, Sankt Augustin (Germany); Chhabda, T.A. [Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, Campus Juelich, Juelich (Germany); Schubert, J.; Zander, W. [Institute of Bio- and Nanosystems (IBN), Research Centre Juelich GmbH, Juelich (Germany); Krueger, P. [Institute of Biochemistry and Molecular Biology, RWTH Aachen, Aachen (Germany); Keusgen, M. [Institute for Pharmaceutical Chemistry, Philipps-University Marburg, Marburg (Germany); Schoening, M.J. [Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, Campus Juelich, Juelich (Germany); Institute of Bio- and Nanosystems (IBN), Research Centre Juelich GmbH, Juelich (Germany)], E-mail: m.j.schoening@fz-juelich.de

    2009-10-30

    The cross-sensitivity of chemical sensors for several metal ions resembles in a way the overlapping sensitivity of some biological sensors, like the optical colour receptors of human retinal cone cells. While it is difficult to assign crisp classification values to measurands based on complex overlapping sensory signals, fuzzy logic offers a possibility to mathematically model such systems. Current work goes into the direction of mixed heavy metal solutions and the combination of fuzzy logic with heavy metal-sensitive, silicon-based chemical sensors for training scenarios of arbitrary sensor/probe combinations in terms of an electronic tongue. Heavy metals play an important role in environmental analysis. As trace elements as well as water impurities released from industrial processes they occur in the environment. In this work, the development of a new fuzzy logic method based on potentiometric measurements performed with three different miniaturised chalcogenide glass sensors in different heavy metal solutions will be presented. The critical validation of the developed fuzzy logic program will be demonstrated by means of measurements in unknown single- and multi-component heavy metal solutions. Limitations of this program and a comparison between calculated and expected values in terms of analyte composition and heavy metal ion concentration will be shown and discussed.

  14. Fall Risk Assessment Through Automatic Combination of Clinical Fall Risk Factors and Body-Worn Sensor Data.

    Science.gov (United States)

    Greene, Barry R; Redmond, Stephen J; Caulfield, Brian

    2017-05-01

    Falls are the leading global cause of accidental death and disability in older adults and are the most common cause of injury and hospitalization. Accurate, early identification of patients at risk of falling, could lead to timely intervention and a reduction in the incidence of fall-related injury and associated costs. We report a statistical method for fall risk assessment using standard clinical fall risk factors (N = 748). We also report a means of improving this method by automatically combining it, with a fall risk assessment algorithm based on inertial sensor data and the timed-up-and-go test. Furthermore, we provide validation data on the sensor-based fall risk assessment method using a statistically independent dataset. Results obtained using cross-validation on a sample of 292 community dwelling older adults suggest that a combined clinical and sensor-based approach yields a classification accuracy of 76.0%, compared to either 73.6% for sensor-based assessment alone, or 68.8% for clinical risk factors alone. Increasing the cohort size by adding an additional 130 subjects from a separate recruitment wave (N = 422), and applying the same model building and validation method, resulted in a decrease in classification performance (68.5% for combined classifier, 66.8% for sensor data alone, and 58.5% for clinical data alone). This suggests that heterogeneity between cohorts may be a major challenge when attempting to develop fall risk assessment algorithms which generalize well. Independent validation of the sensor-based fall risk assessment algorithm on an independent cohort of 22 community dwelling older adults yielded a classification accuracy of 72.7%. Results suggest that the present method compares well to previously reported sensor-based fall risk assessment methods in assessing falls risk. Implementation of objective fall risk assessment methods on a large scale has the potential to improve quality of care and lead to a reduction in associated hospital

  15. Comparing and combining terrestrial laser scanning with ground-and UAV-based imaging for national-level assessment of soil erosion

    Science.gov (United States)

    McShane, Gareth; James, Mike R.; Quinton, John; Anderson, Karen; DeBell, Leon; Evans, Martin; Farrow, Luke; Glendell, Miriam; Jones, Lee; Kirkham, Matthew; Lark, Murray; Rawlins, Barry; Rickson, Jane; Quine, Tim; Wetherelt, Andy; Brazier, Richard

    2014-05-01

    3D topographic or surface models are increasingly being utilised for a wide range of applications and are established tools in geomorphological research. In this pilot study 'a cost effective framework for monitoring soil erosion in England and Wales', funded by the UK Department for Environment, Food and Rural Affairs (Defra), we compare methods of collecting topographic measurements via remote sensing for detailed studies of dynamic processes such as erosion and mass movement. The techniques assessed are terrestrial laser scanning (TLS), and unmanned aerial vehicle (UAV) photography and ground-based photography, processed using structure-from-motion (SfM) 3D reconstruction software. The methods will be applied in regions of different land use, including arable and horticultural, upland and semi natural habitats, and grassland, to quantify visible erosion pathways at the site scale. Volumetric estimates of soil loss will be quantified using the digital surface models (DSMs) provided by each technique and a modelled pre-erosion surface. Visible erosion and severity will be independently established through each technique, with their results compared and combined effectiveness assessed. A fixed delta-wing UAV (QuestUAV, http://www.questuav.com/) captures photos from a range of altitudes and angles over the study area, with automated SfM-based processing enabling rapid orthophoto production to support ground-based data acquisition. At sites with suitable scale erosion features, UAV data will also provide a DSM for volume loss measurement. Terrestrial laser scanning will provide detailed, accurate, high density measurements of the ground surface over long (100s m) distances. Ground-based photography is anticipated to be most useful for characterising small and difficult to view features. By using a consumer-grade digital camera and an SfM-based approach (using Agisoft Photoscan version 1.0.0, http://www.agisoft.ru/products/photoscan/), less expertise and fewer control

  16. Measurement of reaction heats using a polysilicon-based microcalorimetric sensor

    NARCIS (Netherlands)

    Vereshchagina, E.; Wolters, Robertus A.M.; Gardeniers, Johannes G.E.

    2011-01-01

    In this work we present a low-cost, low-power, small sample volume microcalorimetric sensor for the measurement of reaction heats. The polysilicon-based microcalorimetric sensor combines several advantages: (i) complementary metal oxide semiconductor technology (CMOS) for future integration; (ii)

  17. Robust Ground Target Detection by SAR and IR Sensor Fusion Using Adaboost-Based Feature Selection

    Science.gov (United States)

    Kim, Sungho; Song, Woo-Jin; Kim, So-Hyun

    2016-01-01

    Long-range ground targets are difficult to detect in a noisy cluttered environment using either synthetic aperture radar (SAR) images or infrared (IR) images. SAR-based detectors can provide a high detection rate with a high false alarm rate to background scatter noise. IR-based approaches can detect hot targets but are affected strongly by the weather conditions. This paper proposes a novel target detection method by decision-level SAR and IR fusion using an Adaboost-based machine learning scheme to achieve a high detection rate and low false alarm rate. The proposed method consists of individual detection, registration, and fusion architecture. This paper presents a single framework of a SAR and IR target detection method using modified Boolean map visual theory (modBMVT) and feature-selection based fusion. Previous methods applied different algorithms to detect SAR and IR targets because of the different physical image characteristics. One method that is optimized for IR target detection produces unsuccessful results in SAR target detection. This study examined the image characteristics and proposed a unified SAR and IR target detection method by inserting a median local average filter (MLAF, pre-filter) and an asymmetric morphological closing filter (AMCF, post-filter) into the BMVT. The original BMVT was optimized to detect small infrared targets. The proposed modBMVT can remove the thermal and scatter noise by the MLAF and detect extended targets by attaching the AMCF after the BMVT. Heterogeneous SAR and IR images were registered automatically using the proposed RANdom SAmple Region Consensus (RANSARC)-based homography optimization after a brute-force correspondence search using the detected target centers and regions. The final targets were detected by feature-selection based sensor fusion using Adaboost. The proposed method showed good SAR and IR target detection performance through feature selection-based decision fusion on a synthetic database generated

  18. Robust Ground Target Detection by SAR and IR Sensor Fusion Using Adaboost-Based Feature Selection

    Directory of Open Access Journals (Sweden)

    Sungho Kim

    2016-07-01

    Full Text Available Long-range ground targets are difficult to detect in a noisy cluttered environment using either synthetic aperture radar (SAR images or infrared (IR images. SAR-based detectors can provide a high detection rate with a high false alarm rate to background scatter noise. IR-based approaches can detect hot targets but are affected strongly by the weather conditions. This paper proposes a novel target detection method by decision-level SAR and IR fusion using an Adaboost-based machine learning scheme to achieve a high detection rate and low false alarm rate. The proposed method consists of individual detection, registration, and fusion architecture. This paper presents a single framework of a SAR and IR target detection method using modified Boolean map visual theory (modBMVT and feature-selection based fusion. Previous methods applied different algorithms to detect SAR and IR targets because of the different physical image characteristics. One method that is optimized for IR target detection produces unsuccessful results in SAR target detection. This study examined the image characteristics and proposed a unified SAR and IR target detection method by inserting a median local average filter (MLAF, pre-filter and an asymmetric morphological closing filter (AMCF, post-filter into the BMVT. The original BMVT was optimized to detect small infrared targets. The proposed modBMVT can remove the thermal and scatter noise by the MLAF and detect extended targets by attaching the AMCF after the BMVT. Heterogeneous SAR and IR images were registered automatically using the proposed RANdom SAmple Region Consensus (RANSARC-based homography optimization after a brute-force correspondence search using the detected target centers and regions. The final targets were detected by feature-selection based sensor fusion using Adaboost. The proposed method showed good SAR and IR target detection performance through feature selection-based decision fusion on a synthetic

  19. Integration of a satellite ground support system based on analysis of the satellite ground support domain

    Science.gov (United States)

    Pendley, R. D.; Scheidker, E. J.; Levitt, D. S.; Myers, C. R.; Werking, R. D.

    1994-11-01

    This analysis defines a complete set of ground support functions based on those practiced in real space flight operations during the on-orbit phase of a mission. These functions are mapped against ground support functions currently in use by NASA and DOD. Software components to provide these functions can be hosted on RISC-based work stations and integrated to provide a modular, integrated ground support system. Such modular systems can be configured to provide as much ground support functionality as desired. This approach to ground systems has been widely proposed and prototyped both by government institutions and commercial vendors. The combined set of ground support functions we describe can be used as a standard to evaluate candidate ground systems. This approach has also been used to develop a prototype of a modular, loosely-integrated ground support system, which is discussed briefly. A crucial benefit to a potential user is that all the components are flight-qualified, thus giving high confidence in their accuracy and reliability.

  20. Development of paper-based electrochemical sensors for water quality monitoring

    Science.gov (United States)

    Smith, Suzanne; Bezuidenhout, Petroné; Mbanjwa, Mesuli; Zheng, Haitao; Conning, Mariette; Palaniyandy, Nithyadharseni; Ozoemena, Kenneth; Land, Kevin

    2016-02-01

    We present a method for the development of paper-based electrochemical sensors for detection of heavy metals in water samples. Contaminated water leads to serious health problems and environmental issues. Paper is ideally suited for point-of-care testing, as it is low cost, disposable, and multi-functional. Initial sensor designs were manufactured on paper substrates using combinations of inkjet printing and screen printing technologies using silver and carbon inks. Bismuth onion-like carbon nanoparticle ink was manufactured and used as the active material of the sensor for both commercial and paper-based sensors, which were compared using standard electrochemical analysis techniques. The results highlight the potential of paper-based sensors to be used effectively for rapid water quality monitoring at the point-of-need.

  1. Development of mine explosion ground truth smart sensors

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Steven R. [Rocky Mountain Geophysics, Inc., Los Alamos, NM (United States); Harben, Phillip E. [Rocky Mountain Geophysics, Inc., Los Alamos, NM (United States); Jarpe, Steve [Jarpe Data Solutions, Prescott, AZ (United States); Harris, David B. [Deschutes Signal Processing, Maupin, OR (United States)

    2015-09-14

    Accurate seismo-acoustic source location is one of the fundamental aspects of nuclear explosion monitoring. Critical to improved location is the compilation of ground truth data sets for which origin time and location are accurately known. Substantial effort by the National Laboratories and other seismic monitoring groups have been undertaken to acquire and develop ground truth catalogs that form the basis of location efforts (e.g. Sweeney, 1998; Bergmann et al., 2009; Waldhauser and Richards, 2004). In particular, more GT1 (Ground Truth 1 km) events are required to improve three-dimensional velocity models that are currently under development. Mine seismicity can form the basis of accurate ground truth datasets. Although the location of mining explosions can often be accurately determined using array methods (e.g. Harris, 1991) and from overhead observations (e.g. MacCarthy et al., 2008), accurate origin time estimation can be difficult. Occasionally, mine operators will share shot time, location, explosion size and even shot configuration, but this is rarely done, especially in foreign countries. Additionally, shot times provided by mine operators are often inaccurate. An inexpensive, ground truth event detector that could be mailed to a contact, placed in close proximity (< 5 km) to mining regions or earthquake aftershock regions that automatically transmits back ground-truth parameters, would greatly aid in development of ground truth datasets that could be used to improve nuclear explosion monitoring capabilities. We are developing an inexpensive, compact, lightweight smart sensor unit (or units) that could be used in the development of ground truth datasets for the purpose of improving nuclear explosion monitoring capabilities. The units must be easy to deploy, be able to operate autonomously for a significant period of time (> 6 months) and inexpensive enough to be discarded after useful operations have expired (although this may not be part of our business

  2. Absolute Position Sensing Based on a Robust Differential Capacitive Sensor with a Grounded Shield Window

    Directory of Open Access Journals (Sweden)

    Yang Bai

    2016-05-01

    Full Text Available A simple differential capacitive sensor is provided in this paper to measure the absolute positions of length measuring systems. By utilizing a shield window inside the differential capacitor, the measurement range and linearity range of the sensor can reach several millimeters. What is more interesting is that this differential capacitive sensor is only sensitive to one translational degree of freedom (DOF movement, and immune to the vibration along the other two translational DOFs. In the experiment, we used a novel circuit based on an AC capacitance bridge to directly measure the differential capacitance value. The experimental result shows that this differential capacitive sensor has a sensitivity of 2 × 10−4 pF/μm with 0.08 μm resolution. The measurement range of this differential capacitive sensor is 6 mm, and the linearity error are less than 0.01% over the whole absolute position measurement range.

  3. Combining ground penetrating radar and electromagnetic induction for industrial site characterization

    Science.gov (United States)

    Van De Vijver, Ellen; Van Meirvenne, Marc; Saey, Timothy; De Smedt, Philippe; Delefortrie, Samuël; Seuntjens, Piet

    2014-05-01

    Industrial sites pose specific challenges to the conventional way of characterizing soil and groundwater properties through borehole drilling and well monitoring. The subsurface of old industrial sites typically exhibits a large heterogeneity resulting from various anthropogenic interventions, such as the dumping of construction and demolition debris and industrial waste. Also larger buried structures such as foundations, utility infrastructure and underground storage tanks are frequently present. Spills and leaks from industrial activities and leaching of buried waste may have caused additional soil and groundwater contamination. Trying to characterize such a spatially heterogeneous medium with a limited number of localized observations is often problematic. The deployment of mobile proximal soil sensors may be a useful tool to fill up the gaps in between the conventional observations, as these enable measuring soil properties in a non-destructive way. However, because the output of most soil sensors is affected by more than one soil property, the application of only one sensor is generally insufficient to discriminate between all contributing factors. To test a multi-sensor approach, we selected a study area which was part of a former manufactured gas plant site located in one of the seaport areas of Belgium. It has a surface area of 3400 m² and was the location of a phosphate production unit that was demolished at the end of the 1980s. Considering the long and complex history of the site we expected to find a typical "industrial" soil. Furthermore, the studied area was located between buildings of the present industry, entailing additional practical challenges such as the presence of active utilities and aboveground obstacles. The area was surveyed using two proximal soil sensors based on two different geophysical methods: ground penetrating radar (GPR), to image contrasts in dielectric permittivity, and electromagnetic induction (EMI), to measure the apparent

  4. An electrode polarization impedance based flow sensor for low water flow measurement

    International Nuclear Information System (INIS)

    Yan, Tinghu; Sabic, Darko

    2013-01-01

    This note describes an electrode polarization impedance based flow sensor for low water flow measurement. It consists of two pairs of stainless steel electrodes set apart and inserted into a non-conductive flow tube with each pair of electrodes placed diametrically at the opposite sides. The flow sensor is modeled as a typical four-electrode system of which two electrodes are current-carrying and the other two serve as output pick ups. The polarization impedances of the two current carrying electrodes are affected by water flows resulting in changes of differential potential between the two pick-up electrodes which are separated by the same fluid. The interrogation of the two excitation electrodes with dc biased ac signals offers significantly higher sensor sensitivities to flow. The prototype flow sensor constructed for a 20 mm diameter pipeline was able to measure water flow rate as low as tested at 1.06 l h −1 and remained sensitive at a flow rate of 25.18 l h −1 when it was driven with a sinusoidal voltage at 1000 Hz with a peak ac amplitude of 2 V and a dc offset of +8 V. The nonlinear characteristics of the sensor response indicate that the sensor is more sensitive at low flows and will not be able to measure at very high flows. Additional experiments are needed to evaluate the influences of impurities, chemical species, ions constituents, conductivity and temperature over a practical range of residential water conditions, the effects of fluctuating ground signals, measurement uncertainty, power consumption, compensation of effects and practical operations. The flow sensor (principle) presented may be used as (in) a secondary sensor in combination with an existing electronic water meter to extend the low end of measurement range in residential water metering. (technical design note)

  5. Measuring Radiant Emissions from Entire Prescribed Fires with Ground, Airborne and Satellite Sensors RxCADRE 2012

    Science.gov (United States)

    Dickinson, Matthew B.; Hudak, Andrew T.; Zajkowski, Thomas; Loudermilk, E. Louise; Schroeder, Wilfrid; Ellison, Luke; Kremens, Robert L.; Holley, William; Martinez, Otto; Paxton, Alexander; hide

    2015-01-01

    Characterising radiation from wildland fires is an important focus of fire science because radiation relates directly to the combustion process and can be measured across a wide range of spatial extents and resolutions. As part of a more comprehensive set of measurements collected during the 2012 Prescribed Fire Combustion and Atmospheric Dynamics Research (RxCADRE) field campaign, we used ground, airborne and spaceborne sensors to measure fire radiative power (FRP) from whole fires, applying different methods to small (2 ha) and large (.100 ha) burn blocks. For small blocks (n1/46), FRP estimated from an obliquely oriented long-wave infrared (LWIR) camera mounted on a boom lift were compared with FRP derived from combined data from tower-mounted radiometers and remotely piloted aircraft systems (RPAS). For large burn blocks (n1/43), satellite FRP measurements from the Moderate-resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) sensors were compared with near-coincident FRP measurements derived from a LWIR imaging system aboard a piloted aircraft. We describe measurements and consider their strengths and weaknesses. Until quantitative sensors exist for small RPAS, their use in fire research will remain limited. For oblique, airborne and satellite sensors, further FRP measurement development is needed along with greater replication of coincident measurements, which we show to be feasible.

  6. Modeling and Analysis of a Combined Stress-Vibration Fiber Bragg Grating Sensor.

    Science.gov (United States)

    Yao, Kun; Lin, Qijing; Jiang, Zhuangde; Zhao, Na; Tian, Bian; Shi, Peng; Peng, Gang-Ding

    2018-03-01

    A combined stress-vibration sensor was developed to measure stress and vibration simultaneously based on fiber Bragg grating (FBG) technology. The sensor is composed of two FBGs and a stainless steel plate with a special design. The two FBGs sense vibration and stress and the sensor can realize temperature compensation by itself. The stainless steel plate can significantly increase sensitivity of vibration measurement. Theoretical analysis and Finite Element Method (FEM) were used to analyze the sensor's working mechanism. As demonstrated with analysis, the obtained sensor has working range of 0-6000 Hz for vibration sensing and 0-100 MPa for stress sensing, respectively. The corresponding sensitivity for vibration is 0.46 pm/g and the resulted stress sensitivity is 5.94 pm/MPa, while the nonlinearity error for vibration and stress measurement is 0.77% and 1.02%, respectively. Compared to general FBGs, the vibration sensitivity of this sensor is 26.2 times higher. Therefore, the developed sensor can be used to concurrently detect vibration and stress. As this sensor has height of 1 mm and weight of 1.15 g, it is beneficial for minimization and integration.

  7. Sensor Fusion Based Model for Collision Free Mobile Robot Navigation

    Science.gov (United States)

    Almasri, Marwah; Elleithy, Khaled; Alajlan, Abrar

    2015-01-01

    Autonomous mobile robots have become a very popular and interesting topic in the last decade. Each of them are equipped with various types of sensors such as GPS, camera, infrared and ultrasonic sensors. These sensors are used to observe the surrounding environment. However, these sensors sometimes fail and have inaccurate readings. Therefore, the integration of sensor fusion will help to solve this dilemma and enhance the overall performance. This paper presents a collision free mobile robot navigation based on the fuzzy logic fusion model. Eight distance sensors and a range finder camera are used for the collision avoidance approach where three ground sensors are used for the line or path following approach. The fuzzy system is composed of nine inputs which are the eight distance sensors and the camera, two outputs which are the left and right velocities of the mobile robot’s wheels, and 24 fuzzy rules for the robot’s movement. Webots Pro simulator is used for modeling the environment and the robot. The proposed methodology, which includes the collision avoidance based on fuzzy logic fusion model and line following robot, has been implemented and tested through simulation and real time experiments. Various scenarios have been presented with static and dynamic obstacles using one robot and two robots while avoiding obstacles in different shapes and sizes. PMID:26712766

  8. Sensor Fusion Based Model for Collision Free Mobile Robot Navigation

    Directory of Open Access Journals (Sweden)

    Marwah Almasri

    2015-12-01

    Full Text Available Autonomous mobile robots have become a very popular and interesting topic in the last decade. Each of them are equipped with various types of sensors such as GPS, camera, infrared and ultrasonic sensors. These sensors are used to observe the surrounding environment. However, these sensors sometimes fail and have inaccurate readings. Therefore, the integration of sensor fusion will help to solve this dilemma and enhance the overall performance. This paper presents a collision free mobile robot navigation based on the fuzzy logic fusion model. Eight distance sensors and a range finder camera are used for the collision avoidance approach where three ground sensors are used for the line or path following approach. The fuzzy system is composed of nine inputs which are the eight distance sensors and the camera, two outputs which are the left and right velocities of the mobile robot’s wheels, and 24 fuzzy rules for the robot’s movement. Webots Pro simulator is used for modeling the environment and the robot. The proposed methodology, which includes the collision avoidance based on fuzzy logic fusion model and line following robot, has been implemented and tested through simulation and real time experiments. Various scenarios have been presented with static and dynamic obstacles using one robot and two robots while avoiding obstacles in different shapes and sizes.

  9. Development of a Dynamic Web Mapping Service for Vegetation Productivity Using Earth Observation and in situ Sensors in a Sensor Web Based Approach

    Directory of Open Access Journals (Sweden)

    Sytze de Bruin

    2009-03-01

    Full Text Available This paper describes the development of a sensor web based approach which combines earth observation and in situ sensor data to derive typical information offered by a dynamic web mapping service (WMS. A prototype has been developed which provides daily maps of vegetation productivity for the Netherlands with a spatial resolution of 250 m. Daily available MODIS surface reflectance products and meteorological parameters obtained through a Sensor Observation Service (SOS were used as input for a vegetation productivity model. This paper presents the vegetation productivity model, the sensor data sources and the implementation of the automated processing facility. Finally, an evaluation is made of the opportunities and limitations of sensor web based approaches for the development of web services which combine both satellite and in situ sensor sources.

  10. Optimized Autonomous Space In-situ Sensor-Web for volcano monitoring

    Science.gov (United States)

    Song, W.-Z.; Shirazi, B.; Kedar, S.; Chien, S.; Webb, F.; Tran, D.; Davis, A.; Pieri, D.; LaHusen, R.; Pallister, J.; Dzurisin, D.; Moran, S.; Lisowski, M.

    2008-01-01

    In response to NASA's announced requirement for Earth hazard monitoring sensor-web technology, a multidisciplinary team involving sensor-network experts (Washington State University), space scientists (JPL), and Earth scientists (USGS Cascade Volcano Observatory (CVO)), is developing a prototype dynamic and scaleable hazard monitoring sensor-web and applying it to volcano monitoring. The combined Optimized Autonomous Space -In-situ Sensor-web (OASIS) will have two-way communication capability between ground and space assets, use both space and ground data for optimal allocation of limited power and bandwidth resources on the ground, and use smart management of competing demands for limited space assets. It will also enable scalability and seamless infusion of future space and in-situ assets into the sensor-web. The prototype will be focused on volcano hazard monitoring at Mount St. Helens, which has been active since October 2004. The system is designed to be flexible and easily configurable for many other applications as well. The primary goals of the project are: 1) integrating complementary space (i.e., Earth Observing One (EO-1) satellite) and in-situ (ground-based) elements into an interactive, autonomous sensor-web; 2) advancing sensor-web power and communication resource management technology; and 3) enabling scalability for seamless infusion of future space and in-situ assets into the sensor-web. To meet these goals, we are developing: 1) a test-bed in-situ array with smart sensor nodes capable of making autonomous data acquisition decisions; 2) efficient self-organization algorithm of sensor-web topology to support efficient data communication and command control; 3) smart bandwidth allocation algorithms in which sensor nodes autonomously determine packet priorities based on mission needs and local bandwidth information in real-time; and 4) remote network management and reprogramming tools. The space and in-situ control components of the system will be

  11. Microfluidic EBG Sensor Based on Phase-Shift Method Realized Using 3D Printing Technology.

    Science.gov (United States)

    Radonić, Vasa; Birgermajer, Slobodan; Kitić, Goran

    2017-04-18

    In this article, we propose a novel microfluidic microstrip electromagnetic band gap (EBG) sensor realized using cost-effective 3D printing technology. Microstrip sensor allows monitoring of the fluid properties flowing in the microchannel embedded between the microstrip line and ground plane. The sensor's operating principle is based on the phase-shift method, which allows the characterization at a single operating frequency of 6 GHz. The defected electromagnetic band gap (EBG) structure is realized as a pattern in the microstrip ground plane to improve sensor sensitivity. The designed microfluidic channel is fabricated using a fused deposition modelling (FDM) 3D printing process without additional supporting layers, while the conductive layers are realized using sticky aluminium tape. The measurement results show that the change of permittivity of the fluid in the microfluidic channel from 1 to 80 results in the phase-shift difference of almost 90°. The potential application is demonstrated through the implementation of a proposed sensor for the detection of toluene concentration in toluene-methanol mixture where various concentrations of toluene were analysed.

  12. Optical sensors for earth observation. Chikyu kansokuyo kogaku sensor

    Energy Technology Data Exchange (ETDEWEB)

    Ono, A [National Research Laboratory of Metrology, Tsukuba (Japan)

    1991-10-10

    Developments are made on an optical imager (ASTER) used to collect mainly images of land areas and an infrared sounder (IMG) to measure vertical air temperature distribution and vertical concentration distribution of specific gases, as satellite mounted sensors for earth observation. All the sensor characteristics of the ASTER comprising a visible near infrared radiometer, short wave infrared radiometer and thermal infrared radiometer are required to be capable of providing measurement, evaluation and assurance at the required accuracies during the entire life time. A problem to be solved is how to combine the on-ground calibration prior to launching, on-satellite calibration, and calibration between the test site and the sensors. The IMG is a Fourier transform spectroscopic infrared sounder, which is demanded of a high wave resolution over extended periods of time as well as a high radiation measuring capability. Also required are the level elevation of analysis algorithms to solve inverse problems from the observed radiation spectra, and the data base with high accuracy. 19 refs., 4 figs., 4 tabs.

  13. Intercomparison of Unmanned Aerial Vehicle and Ground-Based Narrow Band Spectrometers Applied to Crop Trait Monitoring in Organic Potato Production

    Directory of Open Access Journals (Sweden)

    Marston Héracles Domingues Franceschini

    2017-06-01

    Full Text Available Vegetation properties can be estimated using optical sensors, acquiring data on board of different platforms. For instance, ground-based and Unmanned Aerial Vehicle (UAV-borne spectrometers can measure reflectance in narrow spectral bands, while different modelling approaches, like regressions fitted to vegetation indices, can relate spectra with crop traits. Although monitoring frameworks using multiple sensors can be more flexible, they may result in higher inaccuracy due to differences related to the sensors characteristics, which can affect information sampling. Also organic production systems can benefit from continuous monitoring focusing on crop management and stress detection, but few studies have evaluated applications with this objective. In this study, ground-based and UAV spectrometers were compared in the context of organic potato cultivation. Relatively accurate estimates were obtained for leaf chlorophyll (RMSE = 6.07 µg·cm−2, leaf area index (RMSE = 0.67 m2·m−2, canopy chlorophyll (RMSE = 0.24 g·m−2 and ground cover (RMSE = 5.5% using five UAV-based data acquisitions, from 43 to 99 days after planting. These retrievals are slightly better than those derived from ground-based measurements (RMSE = 7.25 µg·cm−2, 0.85 m2·m−2, 0.28 g·m−2 and 6.8%, respectively, for the same period. Excluding observations corresponding to the first acquisition increased retrieval accuracy and made outputs more comparable between sensors, due to relatively low vegetation cover on this date. Intercomparison of vegetation indices indicated that indices based on the contrast between spectral bands in the visible and near-infrared, like OSAVI, MCARI2 and CIg provided, at certain extent, robust outputs that could be transferred between sensors. Information sampling at plot level by both sensing solutions resulted in comparable discriminative potential concerning advanced stages of late blight incidence. These results indicate that optical

  14. Assessing community exposure to hazardous air pollutants by combining optical remote sensing and "low-cost" sensor technologies

    Science.gov (United States)

    Pikelnaya, O.; Polidori, A.; Wimmer, R.; Mellqvist, J.; Samuelsson, J.; Marianne, E.; Andersson, P.; Brohede, S.; Izos, O.

    2017-12-01

    Industrial facilities such as refineries and oil processing facilities can be sources of chemicals adversely affecting human health, for example aromatic hydrocarbons and formaldehyde. In an urban setting, such as the South Coast Air Basin (SCAB), exposure to harmful air pollutants (HAP's) for residents of communities neighboring such facilities is of serious concern. Traditionally, exposure assessments are performed by modeling a community exposure using emission inventories and data collected at fixed air monitoring sites. However, recent field measurements found that emission inventories may underestimate HAP emissions from refineries; and HAP measurements data from fixed sites is lacking spatial resolution; as a result, the impact of HAP emissions on communities is highly uncertain. The next generation air monitoring technologies can help address these challenges. For example, dense "low-cost" sensors allow continuous monitoring of concentrations of pollutants within communities with high temporal- and spatial- resolution, and optical remote sensing (ORS) technologies offer measurements of emission fluxes and real-time ground-concentration mapping of HAPs. South Coast Air Quality Management District (SCAQMD) is currently conducting a multi-year study using ORS methods and "low-cost" Volatile Organic Compounds (VOCs) sensors to monitor HAP emissions from selected industrial facilities in the SCAB and their ambient concentrations in neighboring communities. For this purpose, quarterly mobile ORS surveys are conducted to quantify facility-wide emissions for VOCs, aromatic hydrocarbons and HCHO, and to collect ground-concentration profiles of these pollutants inside neighboring communities. Additionally, "low-cost" sensor nodes for deployment in neighborhood(s) downwind of the facilities have been developed in order to obtain long-term, granular data on neighborhood VOC concentrations, During this presentation we will discuss initial results of quarterly ORS

  15. The ground based plan

    International Nuclear Information System (INIS)

    1989-01-01

    The paper presents a report of ''The Ground Based Plan'' of the United Kingdom Science and Engineering Research Council. The ground based plan is a plan for research in astronomy and planetary science by ground based techniques. The contents of the report contains a description of:- the scientific objectives and technical requirements (the basis for the Plan), the present organisation and funding for the ground based programme, the Plan, the main scientific features and the further objectives of the Plan. (U.K.)

  16. GEARS: An Enterprise Architecture Based On Common Ground Services

    Science.gov (United States)

    Petersen, S.

    2014-12-01

    Earth observation satellites collect a broad variety of data used in applications that range from weather forecasting to climate monitoring. Within NOAA the National Environmental Satellite Data and Information Service (NESDIS) supports these applications by operating satellites in both geosynchronous and polar orbits. Traditionally NESDIS has acquired and operated its satellites as stand-alone systems with their own command and control, mission management, processing, and distribution systems. As the volume, velocity, veracity, and variety of sensor data and products produced by these systems continues to increase, NESDIS is migrating to a new concept of operation in which it will operate and sustain the ground infrastructure as an integrated Enterprise. Based on a series of common ground services, the Ground Enterprise Architecture System (GEARS) approach promises greater agility, flexibility, and efficiency at reduced cost. This talk describes the new architecture and associated development activities, and presents the results of initial efforts to improve product processing and distribution.

  17. Low Cost and Pipe Conformable Microwave-Based Water-Cut Sensor

    KAUST Repository

    Karimi, Muhammad Akram

    2016-08-11

    Efficient oil production and refining processes require the precise measurement of water content in oil. This paper presents a novel planar microwave sensor for entirely non-intrusive in situ water cut (WC) sensing over the full range of operation, i.e., 0%-100%. A planar configuration has enabled the direct implementation of WC sensor on the pipe surface using low cost method, i.e., screen printing using 3D printed mask. Modified ground plane-based T-resonator design makes this WC sensor usable for the wide range of pipe sizes present in the oil industry. The viability of this sensor has been confirmed through electromagnetic simulations as well as through a prototype characterization. Two cases of oil and water mixtures, namely, separate phases and homogeneous mix, have been studied. Measurements performed over two independently built prototypes show the root mean square variation in results of only 0.1%.

  18. Hydrogel-based piezoresistive sensor for the detection of ethanol

    Directory of Open Access Journals (Sweden)

    J. Erfkamp

    2018-04-01

    Full Text Available This article describes a low-cost sensor for the detection of ethanol in alcoholic beverages, which combines alcohol-sensitive hydrogels based on acrylamide and bisacrylamide and piezoresistive sensors. For reproducible measurements, the reversible swelling and deswelling of the hydrogel were shown via microscopy. The response time of the sensor depends on the swelling kinetics of the hydrogel. The selectivity of the hydrogel was tested in different alcohols. In order to understand the influence of monomer and crosslinker content on the swelling degree and on the sensitivity of the hydrogels, gels with variable concentrations of acrylamide and bisacrylamide were synthesized and characterized in different aqueous solutions with alcohol contents. The first measurements of such hydrogel-based piezoresistive ethanol sensors demonstrated a high sensitivity and a short response time over several measuring cycles.

  19. Disposable Multi-Sensor Unattended Ground Sensor Systems for Detecting Personnel (Systemes de detection multi-capteurs terrestres autonome destines a detecter du personnel)

    Science.gov (United States)

    2015-02-01

    the set of DCT coefficients for all the training data corresponding to the people. Then, the matrix ][ pX can be written as: ][][][ −+ −= ppp XXX ...deployed on two types of ground conditions. This included ARL multi-modal sensors, video and acoustic sensors from the Universities of Memphis and...Mississippi, SASNet from Canada, video from Night Vision Laboratory and Pearls of Wisdom system from Israel operated in conjunction with ARL personnel. This

  20. Modeling Sensor Reliability in Fault Diagnosis Based on Evidence Theory

    Directory of Open Access Journals (Sweden)

    Kaijuan Yuan

    2016-01-01

    Full Text Available Sensor data fusion plays an important role in fault diagnosis. Dempster–Shafer (D-R evidence theory is widely used in fault diagnosis, since it is efficient to combine evidence from different sensors. However, under the situation where the evidence highly conflicts, it may obtain a counterintuitive result. To address the issue, a new method is proposed in this paper. Not only the statistic sensor reliability, but also the dynamic sensor reliability are taken into consideration. The evidence distance function and the belief entropy are combined to obtain the dynamic reliability of each sensor report. A weighted averaging method is adopted to modify the conflict evidence by assigning different weights to evidence according to sensor reliability. The proposed method has better performance in conflict management and fault diagnosis due to the fact that the information volume of each sensor report is taken into consideration. An application in fault diagnosis based on sensor fusion is illustrated to show the efficiency of the proposed method. The results show that the proposed method improves the accuracy of fault diagnosis from 81.19% to 89.48% compared to the existing methods.

  1. Polymer-based blood vessel models with micro-temperature sensors in EVE

    Science.gov (United States)

    Mizoshiri, Mizue; Ito, Yasuaki; Hayakawa, Takeshi; Maruyama, Hisataka; Sakurai, Junpei; Ikeda, Seiichi; Arai, Fumihito; Hata, Seiichi

    2017-04-01

    Cu-based micro-temperature sensors were directly fabricated on poly(dimethylsiloxane) (PDMS) blood vessel models in EVE using a combined process of spray coating and femtosecond laser reduction of CuO nanoparticles. CuO nanoparticle solution coated on a PDMS blood vessel model are thermally reduced and sintered by focused femtosecond laser pulses in atmosphere to write the sensors. After removing the non-irradiated CuO nanoparticles, Cu-based microtemperature sensors are formed. The sensors are thermistor-type ones whose temperature dependences of the resistance are used for measuring temperature inside the blood vessel model. This fabrication technique is useful for direct-writing of Cu-based microsensors and actuators on arbitrary nonplanar substrates.

  2. A multi-sensor study of the impact of ground-based glaciogenic seeding on orogrpahic clouds and precipitation

    Science.gov (United States)

    Pokharel, Binod

    This dissertation examines reflectivity data from three different radar systems, as well as airborne and ground-based in situ particle imaging data, to study the impact of ground-based glaciogenic seeding on orographic clouds and precipitation formed over the mountains in southern Wyoming. The data for this study come from the AgI Seeding Cloud Impact Investigation (ASCII) field campaign conducted over the Sierra Madre mountains in 2012 (ASCII-12) and over the Medicine Bow mountains in 2013 (ASCII-13) in the context of the Wyoming Weather Modification Pilot Project (WWMPP). The campaigns were supported by a network of ground-based instruments, including a microwave radiometer, two profiling Ka-band Micro Rain Radars (MRRs), a Doppler on Wheels (DOW), rawinsondes, a Cloud Particle Imager, and a Parsivel disdrometer. The University of Wyoming King Air with profiling Wyoming Cloud Radar (WCR) conducted nine successful flights in ASCII-12, and eight flights in ASCII-13. WCR profiles from these flights are combined with those from seven other flights, which followed the same geographically-fixed pattern in 2008-09 (pre-ASCII) over the Medicine Bow range. All sampled storms were relatively shallow, with low-level air forced over the target mountain, and cold enough to support ice initiation by silver iodide (AgI) nuclei in cloud. Three detailed case studies are conducted, each with different atmospheric conditions and different cloud and snow growth properties: one case (21 Feb 2012) is stratiform, with strong winds and cloud droplets too small to enable snow growth by accretion (riming). A second case (13 Feb 2012) contains shallow convective cells. Clouds in the third case study (22 Feb 2012) are stratiform but contain numerous large droplets (mode ~35 microm in diameter), large enough for ice particle growth by riming. These cases and all others, each with a treated period following an untreated period, show that a clear seeding signature is not immediately apparent

  3. Capillarity-based preparation system for optical colorimetric sensor arrays.

    Science.gov (United States)

    Luo, Xiao-Gang; Yi, Xin; Bu, Xiang-Nan; Hou, Chang-Jun; Huo, Dan-Qun; Yang, Mei; Fa, Huan-Bao; Lei, Jin-Can

    2017-03-01

    In recent years, optical colorimetric sensor arrays have demonstrated beneficial features, including rapid response, high selectivity, and high specificity; as a result, it has been extensively applied in food inspection and chemical studies, among other fields. There are instruments in the current market available for the preparation of an optical colorimetric sensor array, but it lacks the corresponding research of the preparation mechanism. Therefore, in connection with the main features of this kind of sensor array such as consistency, based on the preparation method of contact spotting, combined with a capillary fluid model, Washburn equation, Laplace equation, etc., this paper develops a diffusion model of an optical colorimetric sensor array during its preparation and sets up an optical colorimetric sensor array preparation system based on this diffusion model. Finally, this paper compares and evaluates the sensor arrays prepared by the system and prepared manually in three aspects such as the quality of array point, response of array, and response result, and the results show that the performance index of the sensor array prepared by a system under this diffusion model is better than that of the sensor array of manual spotting, which meets the needs of the experiment.

  4. The pH-static enzyme sensor : An ISFET-based enzyme sensor, insensitive to the buffer capacity of the sample

    NARCIS (Netherlands)

    van der Schoot, Bart H.; Bergveld, Piet

    1987-01-01

    An ISFET-based urea sensor is combined with a noble-metal electrode which provides continuous coulometric titration of the products of the enzymatic reaction. The sensor thus becomes independent of the buffer capacity of the sample; and because the enzyme is operating at a constant pH, the linear

  5. Electrochemical Sensors Based on Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Md. Aminur Rahman

    2009-03-01

    Full Text Available This review focuses on recent contributions in the development of the electrochemical sensors based on carbon nanotubes (CNTs. CNTs have unique mechanical and electronic properties, combined with chemical stability, and behave electrically as a metal or semiconductor, depending on their structure. For sensing applications, CNTs have many advantages such as small size with larger surface area, excellent electron transfer promoting ability when used as electrodes modifier in electrochemical reactions, and easy protein immobilization with retention of its activity for potential biosensors. CNTs play an important role in the performance of electrochemical biosensors, immunosensors, and DNA biosensors. Various methods have been developed for the design of sensors using CNTs in recent years. Herein we summarize the applications of CNTs in the construction of electrochemical sensors and biosensors along with other nanomaterials and conducting polymers.

  6. Information-based self-organization of sensor nodes of a sensor network

    Science.gov (United States)

    Ko, Teresa H [Castro Valley, CA; Berry, Nina M [Tracy, CA

    2011-09-20

    A sensor node detects a plurality of information-based events. The sensor node determines whether at least one other sensor node is an information neighbor of the sensor node based on at least a portion of the plurality of information-based events. The information neighbor has an overlapping field of view with the sensor node. The sensor node sends at least one communication to the at least one other sensor node that is an information neighbor of the sensor node in response to at least one information-based event of the plurality of information-based events.

  7. Radionuclide Sensors for Environmental Monitoring: From Flow Injection Solid-Phase Absorptiometry to Equilibration-Based Preconcentrating Minicolumn Sensors with Radiometric Detection

    International Nuclear Information System (INIS)

    Grate, Jay W.; Egorov, Oleg B.; O'Hara, Matthew J.; Devol, Timothy A.

    2008-01-01

    The development of in situ sensors for ultratrace detection applications in process control and environmental monitoring remains a significant challenge. Such sensors must meet difficult detection limit requirements while selectively detecting the analyte of interest in complex or otherwise challenging sample matrixes. Nowhere are these requirements more daunting than in the field of radionuclide sensing. The detection limit requirements can be extremely low. Nevertheless, a promising approach to radionuclide sensing based on preconcentrating minicolumn sensors has been developed. In addition, a method of operating such sensors, which we call equilibration-based sensing, has been developed that provides substantial preconcentration and a signal that is proportional to analyte concentration, while eliminating the need for reagents to regenerate the sorbent medium following each measurement. While this equilibration-based sensing method was developed for radionuclide sensing, it can be applied to nonradioactive species as well, given a suitable on-column detection system. By replacing costly sampling and laboratory analysis procedures, in situ sensors could have a significant impact on monitoring and long term stewardship applications. The aim of this review is to cover radionuclide sensors that combine some form of selective sorption with a radiometric detection method, and, as a primary aim, to comprehensively review preconcentrating minicolumn sensors for radionuclide detection. As a secondary aim, we will cover radionuclide sensors that combine sorption and scintillation in formats other than minicolumn sensors. We are particularly concerned with the detection of alpha- and beta-emitting radionuclides, which present particular challenges for measurements in liquid media

  8. Wheel-Based Ice Sensors for Road Vehicles

    Science.gov (United States)

    Arndt, G. Dickey; Fink, Patrick W.; Ngo, Phong H.; Carl, James R.

    2011-01-01

    Wheel-based sensors for detection of ice on roads and approximate measurement of the thickness of the ice are under development. These sensors could be used to alert drivers to hazardous local icing conditions in real time. In addition, local ice-thickness measurements by these sensors could serve as guidance for the minimum amount of sand and salt required to be dispensed locally onto road surfaces to ensure safety, thereby helping road crews to utilize their total supplies of sand and salt more efficiently. Like some aircraft wing-surface ice sensors described in a number of previous NASA Tech Briefs articles, the wheelbased ice sensors are based, variously, on measurements of changes in capacitance and/or in radio-frequency impedance as affected by ice on surfaces. In the case of ice on road surfaces, the measurable changes in capacitance and/or impedance are attributable to differences among the electric permittivities of air, ice, water, concrete, and soil. In addition, a related phenomenon that can be useful for distinguishing between ice and water is a specific transition in the permittivity of ice at a temperature- dependent frequency. This feature also provides a continuous calibration of the sensor to allow for changing road conditions. Several configurations of wheel-based ice sensors are under consideration. For example, in a simple two-electrode capacitor configuration, one of the electrodes would be a circumferential electrode within a tire, and the ground would be used as the second electrode. Optionally, the steel belts that are already standard parts of many tires could be used as the circumferential electrodes. In another example (see figure), multiple electrodes would be embedded in rubber between the steel belt and the outer tire surface. These electrodes would be excited in alternating polarities at one or more suitable audio or radio frequencies to provide nearly continuous monitoring of the road surface under the tire. In still another

  9. The potential of agent-based modelling for verification of people trajectories based on smartphone sensor data

    International Nuclear Information System (INIS)

    Hillen, F; Ehlers, M; Höfle, B; Reinartz, P

    2014-01-01

    In this paper the potential of smartphone sensor data for verification of people trajectories derived from airborne remote sensing data are investigated and discussed based on simulated test recordings in the city of Osnabrueck, Germany. For this purpose, the airborne imagery is simulated by images taken from a high building with a typical single lens reflex camera. The smartphone data required for the analysis of the potential is simultaneously recorded by test persons on the ground. In a second step, the quality of the smartphone sensor data is evaluated regarding the integration into simulation and modelling approaches. In this context we studied the potential of the agent-based modelling technique concerning the verification of people trajectories

  10. Validation of OMI erythemal doses with multi-sensor ground-based measurements in Thessaloniki, Greece

    Science.gov (United States)

    Zempila, Melina Maria; Fountoulakis, Ilias; Taylor, Michael; Kazadzis, Stelios; Arola, Antti; Koukouli, Maria Elissavet; Bais, Alkiviadis; Meleti, Chariklia; Balis, Dimitrios

    2018-06-01

    The aim of this study is to validate the Ozone Monitoring Instrument (OMI) erythemal dose rates using ground-based measurements in Thessaloniki, Greece. In the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki, a Yankee Environmental System UVB-1 radiometer measures the erythemal dose rates every minute, and a Norsk Institutt for Luftforskning (NILU) multi-filter radiometer provides multi-filter based irradiances that were used to derive erythemal dose rates for the period 2005-2014. Both these datasets were independently validated against collocated UV irradiance spectra from a Brewer MkIII spectrophotometer. Cloud detection was performed based on measurements of the global horizontal radiation from a Kipp & Zonen pyranometer and from NILU measurements in the visible range. The satellite versus ground observation validation was performed taking into account the effect of temporal averaging, limitations related to OMI quality control criteria, cloud conditions, the solar zenith angle and atmospheric aerosol loading. Aerosol optical depth was also retrieved using a collocated CIMEL sunphotometer in order to assess its impact on the comparisons. The effect of total ozone columns satellite versus ground-based differences on the erythemal dose comparisons was also investigated. Since most of the public awareness alerts are based on UV Index (UVI) classifications, an analysis and assessment of OMI capability for retrieving UVIs was also performed. An overestimation of the OMI erythemal product by 3-6% and 4-8% with respect to ground measurements is observed when examining overpass and noontime estimates respectively. The comparisons revealed a relatively small solar zenith angle dependence, with the OMI data showing a slight dependence on aerosol load, especially at high aerosol optical depth values. A mean underestimation of 2% in OMI total ozone columns under cloud-free conditions was found to lead to an overestimation in OMI erythemal

  11. Combined raman and IR fiber-based sensor for gas detection

    Science.gov (United States)

    Carter, Jerry C; Chan, James W; Trebes, James E; Angel, Stanley M; Mizaikoff, Boris

    2014-06-24

    A double-pass fiber-optic based spectroscopic gas sensor delivers Raman excitation light and infrared light to a hollow structure, such as a hollow fiber waveguide, that contains a gas sample of interest. A retro-reflector is placed at the end of this hollow structure to send the light back through the waveguide where the light is detected at the same end as the light source. This double pass retro reflector design increases the interaction path length of the light and the gas sample, and also reduces the form factor of the hollow structure.

  12. Microfluidic EBG Sensor Based on Phase-Shift Method Realized Using 3D Printing Technology

    Directory of Open Access Journals (Sweden)

    Vasa Radonić

    2017-04-01

    Full Text Available In this article, we propose a novel microfluidic microstrip electromagnetic band gap (EBG sensor realized using cost-effective 3D printing technology. Microstrip sensor allows monitoring of the fluid properties flowing in the microchannel embedded between the microstrip line and ground plane. The sensor’s operating principle is based on the phase-shift method, which allows the characterization at a single operating frequency of 6 GHz. The defected electromagnetic band gap (EBG structure is realized as a pattern in the microstrip ground plane to improve sensor sensitivity. The designed microfluidic channel is fabricated using a fused deposition modelling (FDM 3D printing process without additional supporting layers, while the conductive layers are realized using sticky aluminium tape. The measurement results show that the change of permittivity of the fluid in the microfluidic channel from 1 to 80 results in the phase-shift difference of almost 90°. The potential application is demonstrated through the implementation of a proposed sensor for the detection of toluene concentration in toluene–methanol mixture where various concentrations of toluene were analysed.

  13. Optimized autonomous space in-situ sensor web for volcano monitoring

    Science.gov (United States)

    Song, W.-Z.; Shirazi, B.; Huang, R.; Xu, M.; Peterson, N.; LaHusen, R.; Pallister, J.; Dzurisin, D.; Moran, S.; Lisowski, M.; Kedar, S.; Chien, S.; Webb, F.; Kiely, A.; Doubleday, J.; Davies, A.; Pieri, D.

    2010-01-01

    In response to NASA's announced requirement for Earth hazard monitoring sensor-web technology, a multidisciplinary team involving sensor-network experts (Washington State University), space scientists (JPL), and Earth scientists (USGS Cascade Volcano Observatory (CVO)), have developed a prototype of dynamic and scalable hazard monitoring sensor-web and applied it to volcano monitoring. The combined Optimized Autonomous Space In-situ Sensor-web (OASIS) has two-way communication capability between ground and space assets, uses both space and ground data for optimal allocation of limited bandwidth resources on the ground, and uses smart management of competing demands for limited space assets. It also enables scalability and seamless infusion of future space and in-situ assets into the sensor-web. The space and in-situ control components of the system are integrated such that each element is capable of autonomously tasking the other. The ground in-situ was deployed into the craters and around the flanks of Mount St. Helens in July 2009, and linked to the command and control of the Earth Observing One (EO-1) satellite. ?? 2010 IEEE.

  14. Probabilistic Location-based Routing Protocol for Mobile Wireless Sensor Networks with Intermittent Communication

    Directory of Open Access Journals (Sweden)

    Sho KUMAGAI

    2015-02-01

    Full Text Available In a sensor network, sensor data messages reach the nearest stationary sink node connected to the Internet by wireless multihop transmissions. Recently, various mobile sensors are available due to advances of robotics technologies and communication technologies. A location based message-by-message routing protocol, such as Geographic Distance Routing (GEDIR is suitable for such mobile wireless networks; however, it is required for each mobile wireless sensor node to know the current locations of all its neighbor nodes. On the other hand, various intermittent communication methods for a low power consumption requirement have been proposed for wireless sensor networks. Intermittent Receiver-driven Data Transmission (IRDT is one of the most efficient methods; however, it is difficult to combine the location based routing and the intermittent communication. In order to solve this problem, this paper proposes a probabilistic approach IRDT-GEDIR with the help of one of the solutions of the secretaries problem. Here, each time a neighbor sensor node wakes up from its sleep mode, an intermediate sensor node determines whether it forwards its buffered sensor data messages to it or not based on an estimation of achieved pseudo speed of the messages. Simulation experiments show that IRDT-GEDIR achieves higher pseudo speed of sensor data message transmissions and shorter transmission delay than achieves shorter transmission delay than the two naive combinations of IRDT and GEDIR in sensor networks with mobile sensor nodes and a stationary sink node. In addition, the guideline of the estimated numbers of the neighbor nodes of each intermediate sensor node is provided based on the results of the simulation experiments to apply the probabilistic approach IRDT-GEDIR.

  15. Piezoresistive Carbon-based Hybrid Sensor for Body-Mounted Biomedical Applications

    Science.gov (United States)

    Melnykowycz, M.; Tschudin, M.; Clemens, F.

    2017-02-01

    For body-mounted sensor applications, the evolution of soft condensed matter sensor (SCMS) materials offer conformability andit enables mechanical compliance between the body surface and the sensing mechanism. A piezoresistive hybrid sensor and compliant meta-material sub-structure provided a way to engineer sensor physical designs through modification of the mechanical properties of the compliant design. A piezoresistive fiber sensor was produced by combining a thermoplastic elastomer (TPE) matrix with Carbon Black (CB) particles in 1:1 mass ratio. Feedstock was extruded in monofilament fiber form (diameter of 300 microns), resulting in a highly stretchable sensor (strain sensor range up to 100%) with linear resistance signal response. The soft condensed matter sensor was integrated into a hybrid design including a 3D printed metamaterial structure combined with a soft silicone. An auxetic unit cell was chosen (with negative Poisson’s Ratio) in the design in order to combine with the soft silicon, which exhibits a high Poisson’s Ratio. The hybrid sensor design was subjected to mechanical tensile testing up to 50% strain (with gauge factor calculation for sensor performance), and then utilized for strain-based sensing applications on the body including gesture recognition and vital function monitoring including blood pulse-wave and breath monitoring. A 10 gesture Natural User Interface (NUI) test protocol was utilized to show the effectiveness of a single wrist-mounted sensor to identify discrete gestures including finger and hand motions. These hand motions were chosen specifically for Human Computer Interaction (HCI) applications. The blood pulse-wave signal was monitored with the hand at rest, in a wrist-mounted. In addition different breathing patterns were investigated, including normal breathing and coughing, using a belt and chest-mounted configuration.

  16. Sensor fusion-based map building for mobile robot exploration

    International Nuclear Information System (INIS)

    Ribo, M.

    2000-01-01

    To carry out exploration tasks in unknown or partially unknown environments, a mobile robot needs to acquire and maintain models of its environment. In doing so, several sensors of same nature and/or heterogeneous sensor configurations may be used by the robot to achieve reliable performances. However, this in turn poses the problem of sensor fusion-based map building: How to interpret, combine and integrate sensory information in order to build a proper representation of the environment. Specifically, the goal of this thesis is to probe integration algorithms for Occupancy Grid (OG) based map building using odometry, ultrasonic rangefinders, and stereo vision. Three different uncertainty calculi are presented here which are used for sensor fusion-based map building purposes. They are based on probability theory, Dempster-Shafer theory of evidence, and fuzzy set theory. Besides, two different sensor models are depicted which are used to translate sensing data into range information. Experimental examples of OGs built from real data recorded by two robots in office-like environment are presented. They show the feasibility of the proposed approach for building both sonar and visual based OGs. A comparison among the presented uncertainty calculi is performed in a sonar-based framework. Finally, the fusion of both sonar and visual information based of the fuzzy set theory is depicted. (author)

  17. Incremental Structured Dictionary Learning for Video Sensor-Based Object Tracking

    Science.gov (United States)

    Xue, Ming; Yang, Hua; Zheng, Shibao; Zhou, Yi; Yu, Zhenghua

    2014-01-01

    To tackle robust object tracking for video sensor-based applications, an online discriminative algorithm based on incremental discriminative structured dictionary learning (IDSDL-VT) is presented. In our framework, a discriminative dictionary combining both positive, negative and trivial patches is designed to sparsely represent the overlapped target patches. Then, a local update (LU) strategy is proposed for sparse coefficient learning. To formulate the training and classification process, a multiple linear classifier group based on a K-combined voting (KCV) function is proposed. As the dictionary evolves, the models are also trained to timely adapt the target appearance variation. Qualitative and quantitative evaluations on challenging image sequences compared with state-of-the-art algorithms demonstrate that the proposed tracking algorithm achieves a more favorable performance. We also illustrate its relay application in visual sensor networks. PMID:24549252

  18. Linear all-fiber temperature sensor based on macro-bent erbium doped fiber

    International Nuclear Information System (INIS)

    Hajireza, P; Cham, C L; Kumar, D; Abdul-Rashid, H A; Emami, S D; Harun, S W

    2010-01-01

    A new all fiber temperature sensor is proposed and demonstrated based on a pair of 1 meter erbium-doped fiber (EDF), which are respectively macro-bent and straight. The sensor has a linear normalized loss (dB) response to temperature at 6.5 mm bending radius and 1580 nm input wavelength. The main advantage of this sensor is high temperature resolution (less than 1°C) and sensitivity (0.03 dB/°C) due to combination of temperature dependence of EDF and bending loss. The proposed silica based sensor, has the potential for wide range and high temperature applications in harsh environments

  19. Reputation-based secure sensor localization in wireless sensor networks.

    Science.gov (United States)

    He, Jingsha; Xu, Jing; Zhu, Xingye; Zhang, Yuqiang; Zhang, Ting; Fu, Wanqing

    2014-01-01

    Location information of sensor nodes in wireless sensor networks (WSNs) is very important, for it makes information that is collected and reported by the sensor nodes spatially meaningful for applications. Since most current sensor localization schemes rely on location information that is provided by beacon nodes for the regular sensor nodes to locate themselves, the accuracy of localization depends on the accuracy of location information from the beacon nodes. Therefore, the security and reliability of the beacon nodes become critical in the localization of regular sensor nodes. In this paper, we propose a reputation-based security scheme for sensor localization to improve the security and the accuracy of sensor localization in hostile or untrusted environments. In our proposed scheme, the reputation of each beacon node is evaluated based on a reputation evaluation model so that regular sensor nodes can get credible location information from highly reputable beacon nodes to accomplish localization. We also perform a set of simulation experiments to demonstrate the effectiveness of the proposed reputation-based security scheme. And our simulation results show that the proposed security scheme can enhance the security and, hence, improve the accuracy of sensor localization in hostile or untrusted environments.

  20. Optical Communication System for Remote Monitoring and Adaptive Control of Distributed Ground Sensors Exhibiting Collective Intelligence

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, S.M.; Stantz, K.M.; Trahan, M.W.; Wagner, J.S.

    1998-11-01

    Comprehensive management of the battle-space has created new requirements in information management, communication, and interoperability as they effect surveillance and situational awareness. The objective of this proposal is to expand intelligent controls theory to produce a uniquely powerful implementation of distributed ground-based measurement incorporating both local collective behavior, and interoperative global optimization for sensor fusion and mission oversight. By using a layered hierarchal control architecture to orchestrate adaptive reconfiguration of autonomous robotic agents, we can improve overall robustness and functionality in dynamic tactical environments without information bottlenecks. In this concept, each sensor is equipped with a miniaturized optical reflectance modulator which is interactively monitored as a remote transponder using a covert laser communication protocol from a remote mothership or operative. Robot data-sharing at the ground level can be leveraged with global evaluation criteria, including terrain overlays and remote imaging data. Information sharing and distributed intelli- gence opens up a new class of remote-sensing applications in which small single-function autono- mous observers at the local level can collectively optimize and measure large scale ground-level signals. AS the need for coverage and the number of agents grows to improve spatial resolution, cooperative behavior orchestrated by a global situational awareness umbrella will be an essential ingredient to offset increasing bandwidth requirements within the net. A system of the type described in this proposal will be capable of sensitively detecting, tracking, and mapping spatial distributions of measurement signatures which are non-stationary or obscured by clutter and inter- fering obstacles by virtue of adaptive reconfiguration. This methodology could be used, for example, to field an adaptive ground-penetrating radar for detection of underground structures in

  1. Wearable-Sensor-Based Classification Models of Faller Status in Older Adults.

    Directory of Open Access Journals (Sweden)

    Jennifer Howcroft

    Full Text Available Wearable sensors have potential for quantitative, gait-based, point-of-care fall risk assessment that can be easily and quickly implemented in clinical-care and older-adult living environments. This investigation generated models for wearable-sensor based fall-risk classification in older adults and identified the optimal sensor type, location, combination, and modelling method; for walking with and without a cognitive load task. A convenience sample of 100 older individuals (75.5 ± 6.7 years; 76 non-fallers, 24 fallers based on 6 month retrospective fall occurrence walked 7.62 m under single-task and dual-task conditions while wearing pressure-sensing insoles and tri-axial accelerometers at the head, pelvis, and left and right shanks. Participants also completed the Activities-specific Balance Confidence scale, Community Health Activities Model Program for Seniors questionnaire, six minute walk test, and ranked their fear of falling. Fall risk classification models were assessed for all sensor combinations and three model types: multi-layer perceptron neural network, naïve Bayesian, and support vector machine. The best performing model was a multi-layer perceptron neural network with input parameters from pressure-sensing insoles and head, pelvis, and left shank accelerometers (accuracy = 84%, F1 score = 0.600, MCC score = 0.521. Head sensor-based models had the best performance of the single-sensor models for single-task gait assessment. Single-task gait assessment models outperformed models based on dual-task walking or clinical assessment data. Support vector machines and neural networks were the best modelling technique for fall risk classification. Fall risk classification models developed for point-of-care environments should be developed using support vector machines and neural networks, with a multi-sensor single-task gait assessment.

  2. Downscaling Satellite Data for Predicting Catchment-scale Root Zone Soil Moisture with Ground-based Sensors and an Ensemble Kalman Filter

    Science.gov (United States)

    Lin, H.; Baldwin, D. C.; Smithwick, E. A. H.

    2015-12-01

    Predicting root zone (0-100 cm) soil moisture (RZSM) content at a catchment-scale is essential for drought and flood predictions, irrigation planning, weather forecasting, and many other applications. Satellites, such as the NASA Soil Moisture Active Passive (SMAP), can estimate near-surface (0-5 cm) soil moisture content globally at coarse spatial resolutions. We develop a hierarchical Ensemble Kalman Filter (EnKF) data assimilation modeling system to downscale satellite-based near-surface soil moisture and to estimate RZSM content across the Shale Hills Critical Zone Observatory at a 1-m resolution in combination with ground-based soil moisture sensor data. In this example, a simple infiltration model within the EnKF-model has been parameterized for 6 soil-terrain units to forecast daily RZSM content in the catchment from 2009 - 2012 based on AMSRE. LiDAR-derived terrain variables define intra-unit RZSM variability using a novel covariance localization technique. This method also allows the mapping of uncertainty with our RZSM estimates for each time-step. A catchment-wide satellite-to-surface downscaling parameter, which nudges the satellite measurement closer to in situ near-surface data, is also calculated for each time-step. We find significant differences in predicted root zone moisture storage for different terrain units across the experimental time-period. Root mean square error from a cross-validation analysis of RZSM predictions using an independent dataset of catchment-wide in situ Time-Domain Reflectometry (TDR) measurements ranges from 0.060-0.096 cm3 cm-3, and the RZSM predictions are significantly (p < 0.05) correlated with TDR measurements [r = 0.47-0.68]. The predictive skill of this data assimilation system is similar to the Penn State Integrated Hydrologic Modeling (PIHM) system. Uncertainty estimates are significantly (p < 0.05) correlated to cross validation error during wet and dry conditions, but more so in dry summer seasons. Developing an

  3. Distance Based Method for Outlier Detection of Body Sensor Networks

    Directory of Open Access Journals (Sweden)

    Haibin Zhang

    2016-01-01

    Full Text Available We propose a distance based method for the outlier detection of body sensor networks. Firstly, we use a Kernel Density Estimation (KDE to calculate the probability of the distance to k nearest neighbors for diagnosed data. If the probability is less than a threshold, and the distance of this data to its left and right neighbors is greater than a pre-defined value, the diagnosed data is decided as an outlier. Further, we formalize a sliding window based method to improve the outlier detection performance. Finally, to estimate the KDE by training sensor readings with errors, we introduce a Hidden Markov Model (HMM based method to estimate the most probable ground truth values which have the maximum probability to produce the training data. Simulation results show that the proposed method possesses a good detection accuracy with a low false alarm rate.

  4. Progress report of FY 1999 activities: The application of Kalman filtering to derive water vapor profiles from combined ground-based sensors: Raman lidar, microwave radiometers, GPS, and radiosondes

    International Nuclear Information System (INIS)

    Edgeworth R. Westwater; Yong Han

    1999-01-01

    Previously, the proposers have delivered to ARM a documented algorithm, that is now applied operationally, and which derives water vapor profiles from combined remote sensor measurements of water vapor radiometers, cloud-base ceilometers, and radio acoustic sounding systems (RASS). With the expanded deployment of a Raman lidar at the CART Central Facility, high quality, high vertical-resolution, water vapor profiles will be provided during nighttime clear conditions, and during clear daytime conditions, to somewhat lower altitudes. The object of this effort is to use Kalman Filtering, previously applied to the combination of nighttime Raman lidar and microwave radiometer data, to derive high-quality water vapor profiles, during non-precipitating conditions, from data routinely available at the CART site. Input data to the algorithm would include: Raman lidar data, highly quality-controlled data of integrated moisture from microwave radiometers and GPS, RASS, and radiosondes. While analyzing data obtained during the Water Vapor Intensive Operating Period'97 at the SGP CART site in central Oklahoma, several questions arose about the calibration of the ARM microwave radiometers (MWR). A large portion of this years effort was a thorough analysis of the many factors that are important for the calibration of this instrument through the tip calibration method and the development of algorithms to correct this procedure. An open literature publication describing this analysis has been accepted

  5. A novel self-powered wireless temperature sensor based on thermoelectric generators

    International Nuclear Information System (INIS)

    Shi, Yongming; Wang, Yao; Deng, Yuan; Gao, Hongli; Lin, Zhen; Zhu, Wei; Ye, Huihong

    2014-01-01

    Highlights: • A self-powered temperature sensor, based on thermoelectric generator, is presented. • This novel sensor can operate without any batteries or other power sources. • This sensor combines signal sensing and power supplying together. • The measurement error is 0.5 K during the sensor operating period. • This sensor can detect temperature fluctuation situations such as fire disaster. - Abstract: A novel self-powered wireless temperature sensor has been designed and presented for solving the power supply problem of temperature sensors. This sensor can autonomously measure temperature under positive temperature fluctuation situations. The self-powered characteristic, realized by using four thermoelectric generators, enables the sensor to operate without any batteries or other power sources. In order to obtain these features, attentions are not only focused on the method to combine signal sensing and power generating together, but also on the method to improve measurement accuracy. Experimental results confirm that this novel sensor has excellent measurement accuracy. The measured performance is consistent with the calculated characteristics. For typical application, this self-powered temperature sensor can detect fire before it develops to flashover state. And the maximum detection distance grows with the growth of burning rate. All the results indicate this innovative sensor is a promising self-powered device which can be used to measure temperature value in positive temperature fluctuation situations

  6. Intelligent sensor networks the integration of sensor networks, signal processing and machine learning

    CERN Document Server

    Hu, Fei

    2012-01-01

    Although governments worldwide have invested significantly in intelligent sensor network research and applications, few books cover intelligent sensor networks from a machine learning and signal processing perspective. Filling this void, Intelligent Sensor Networks: The Integration of Sensor Networks, Signal Processing and Machine Learning focuses on the close integration of sensing, networking, and smart signal processing via machine learning. Based on the world-class research of award-winning authors, the book provides a firm grounding in the fundamentals of intelligent sensor networks, incl

  7. Optimization of Serial Combined System of Ground-Coupled Heat Pump and Solar Collector

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jun; CHEN Yan; LU Suzhen; CUI Junkui

    2009-01-01

    A mathematical optimization model was set up for a ground-solar combined system based on in-situ experimental results,in which the solar collector was combined serially with a ground-coupled heat pump(GCHP).The universal optimal equations were solved by the constrained variable metric method considering both the performance and economics.Then the model was applied to a specific case concerning an actual solar assisted GCHP system for space heating.The results indicated a system coefficient of performance(COP)of 3.9 for the optimal method under the seriaI heating mode,and 3.2 for the conventional one.In addition,the optimum solution also showed advantages in energy and cost saving.1eading to a 16.7%improvement in the heat pump performance at 17.2%less energy consumption and 11.8%lower annual cost,respectively.

  8. Incremental Structured Dictionary Learning for Video Sensor-Based Object Tracking

    Directory of Open Access Journals (Sweden)

    Ming Xue

    2014-02-01

    Full Text Available To tackle robust object tracking for video sensor-based applications, an online discriminative algorithm based on incremental discriminative structured dictionary learning (IDSDL-VT is presented. In our framework, a discriminative dictionary combining both positive, negative and trivial patches is designed to sparsely represent the overlapped target patches. Then, a local update (LU strategy is proposed for sparse coefficient learning. To formulate the training and classification process, a multiple linear classifier group based on a K-combined voting (KCV function is proposed. As the dictionary evolves, the models are also trained to timely adapt the target appearance variation. Qualitative and quantitative evaluations on challenging image sequences compared with state-of-the-art algorithms demonstrate that the proposed tracking algorithm achieves a more favorable performance. We also illustrate its relay application in visual sensor networks.

  9. A novel capacitive absolute positioning sensor based on time grating with nanometer resolution

    Science.gov (United States)

    Pu, Hongji; Liu, Hongzhong; Liu, Xiaokang; Peng, Kai; Yu, Zhicheng

    2018-05-01

    The present work proposes a novel capacitive absolute positioning sensor based on time grating. The sensor includes a fine incremental-displacement measurement component combined with a coarse absolute-position measurement component to obtain high-resolution absolute positioning measurements. A single row type sensor was proposed to achieve fine displacement measurement, which combines the two electrode rows of a previously proposed double-row type capacitive displacement sensor based on time grating into a single row. To achieve absolute positioning measurement, the coarse measurement component is designed as a single-row type displacement sensor employing a single spatial period over the entire measurement range. In addition, this component employs a rectangular induction electrode and four groups of orthogonal discrete excitation electrodes with half-sinusoidal envelope shapes, which were formed by alternately extending the rectangular electrodes of the fine measurement component. The fine and coarse measurement components are tightly integrated to form a compact absolute positioning sensor. A prototype sensor was manufactured using printed circuit board technology for testing and optimization of the design in conjunction with simulations. Experimental results show that the prototype sensor achieves a ±300 nm measurement accuracy with a 1 nm resolution over a displacement range of 200 mm when employing error compensation. The proposed sensor is an excellent alternative to presently available long-range absolute nanometrology sensors owing to its low cost, simple structure, and ease of manufacturing.

  10. Performance Evaluation of Page Migration Scheme for NVRAM-Based Wireless Sensor Nodes

    OpenAIRE

    Ryu, Yeonseung

    2013-01-01

    A wireless sensor network consists of low-powered and multifunctional sensor nodes. Since each sensor node is operated by a battery, the energy management has become one of the critical design challenges in wireless sensor networks. Some recent studies have shown that DRAM-based main memory spends a significant portion of the total system power. In this paper, we studied a buffer management scheme for hybrid main memory that combines low-power nonvolatile RAM (NVRAM) and DRAM in order to redu...

  11. A sensor and video based ontology for activity recognition in smart environments.

    Science.gov (United States)

    Mitchell, D; Morrow, Philip J; Nugent, Chris D

    2014-01-01

    Activity recognition is used in a wide range of applications including healthcare and security. In a smart environment activity recognition can be used to monitor and support the activities of a user. There have been a range of methods used in activity recognition including sensor-based approaches, vision-based approaches and ontological approaches. This paper presents a novel approach to activity recognition in a smart home environment which combines sensor and video data through an ontological framework. The ontology describes the relationships and interactions between activities, the user, objects, sensors and video data.

  12. Statistical methods of combining information: Applications to sensor data fusion

    Energy Technology Data Exchange (ETDEWEB)

    Burr, T.

    1996-12-31

    This paper reviews some statistical approaches to combining information from multiple sources. Promising new approaches will be described, and potential applications to combining not-so-different data sources such as sensor data will be discussed. Experiences with one real data set are described.

  13. Bluetooth-based wireless sensor networks

    Science.gov (United States)

    You, Ke; Liu, Rui Qiang

    2007-11-01

    In this work a Bluetooth-based wireless sensor network is proposed. In this bluetooth-based wireless sensor networks, information-driven star topology and energy-saved mode are used, through which a blue master node can control more than seven slave node, the energy of each sensor node is reduced and secure management of each sensor node is improved.

  14. Novel glucose fiber sensor combining ThFBG with GOD

    Science.gov (United States)

    Li, Mengmeng; Zhou, Ciming; Fan, Dian; Ou, Yiwen

    2016-10-01

    We propose a novel glucose fiber optic sensor combining a thinned cladding fiber Bragg grating (ThFBG) with glucose oxidase (GOD). By immobilizing GOD on the surface of a ThFBG, the fabricated sensor can obtain a high specificity to glucose. Because of the evanescent field, the sensor is very sensitive to the ambient refractive index change arising from the catalytic reaction between glucose and GOD. A four-level fiber model was simulated and verified the precision of the sensing principle. Two methods, glutaraldehyde crosslinking method (GCM) and 3-aminopropyl triethoxysilane covalent coupling method (ATCCM), were experimentally utilized to immobilize GOD. And sensor fabricated with the method ATCCM shows a measurement range of 0-0.82 mg/mL which is better than the sensor fabricated with the method GCM with measurement range of 0-0.67 mg/mL under the same condition. By using ATCCM to immobilize GOD with different concentrations, three sensors were fabricated and used for glucose measurement by monitoring the Bragg wavelength (λb) shifts, the results indicate a good linear relationship between wavelength shift and glucose concentration within a specific range, and the measurement range increases as GOD concentration increases. The highest sensitivity of sensor reaches up to 0.0549 nm/(mg.mL-1). The proposed sensor has distinct advantages in sensing structure, cost and specificity.

  15. Ground-based lidar and microwave radiometry synergy for high vertical resolution absolute humidity profiling

    Science.gov (United States)

    Barrera-Verdejo, María; Crewell, Susanne; Löhnert, Ulrich; Orlandi, Emiliano; Di Girolamo, Paolo

    2016-08-01

    Continuous monitoring of atmospheric humidity profiles is important for many applications, e.g., assessment of atmospheric stability and cloud formation. Nowadays there are a wide variety of ground-based sensors for atmospheric humidity profiling. Unfortunately there is no single instrument able to provide a measurement with complete vertical coverage, high vertical and temporal resolution and good performance under all weather conditions, simultaneously. For example, Raman lidar (RL) measurements can provide water vapor with a high vertical resolution, albeit with limited vertical coverage, due to sunlight contamination and the presence of clouds. Microwave radiometers (MWRs) receive water vapor information throughout the troposphere, though their vertical resolution is poor. In this work, we present an MWR and RL system synergy, which aims to overcome the specific sensor limitations. The retrieval algorithm combining these two instruments is an optimal estimation method (OEM), which allows for an uncertainty analysis of the retrieved profiles. The OEM combines measurements and a priori information, taking the uncertainty of both into account. The measurement vector consists of a set of MWR brightness temperatures and RL water vapor profiles. The method is applied to a 2-month field campaign around Jülich (Germany), focusing on clear sky periods. Different experiments are performed to analyze the improvements achieved via the synergy compared to the individual retrievals. When applying the combined retrieval, on average the theoretically determined absolute humidity uncertainty is reduced above the last usable lidar range by a factor of ˜ 2 with respect to the case where only RL measurements are used. The analysis in terms of degrees of freedom per signal reveal that most information is gained above the usable lidar range, especially important during daytime when the lidar vertical coverage is limited. The retrieved profiles are further evaluated using

  16. Seismic Target Classification Using a Wavelet Packet Manifold in Unattended Ground Sensors Systems

    Directory of Open Access Journals (Sweden)

    Enliang Song

    2013-07-01

    Full Text Available One of the most challenging problems in target classification is the extraction of a robust feature, which can effectively represent a specific type of targets. The use of seismic signals in unattended ground sensor (UGS systems makes this problem more complicated, because the seismic target signal is non-stationary, geology-dependent and with high-dimensional feature space. This paper proposes a new feature extraction algorithm, called wavelet packet manifold (WPM, by addressing the neighborhood preserving embedding (NPE algorithm of manifold learning on the wavelet packet node energy (WPNE of seismic signals. By combining non-stationary information and low-dimensional manifold information, WPM provides a more robust representation for seismic target classification. By using a K nearest neighbors classifier on the WPM signature, the algorithm of wavelet packet manifold classification (WPMC is proposed. Experimental results show that the proposed WPMC can not only reduce feature dimensionality, but also improve the classification accuracy up to 95.03%. Moreover, compared with state-of-the-art methods, WPMC is more suitable for UGS in terms of recognition ratio and computational complexity.

  17. Estimation of ground reaction forces and joint moments on the basis on plantar pressure insoles and wearable sensors for joint angle measurement.

    Science.gov (United States)

    Ostaszewski, Michal; Pauk, Jolanta

    2018-05-16

    Gait analysis is a useful tool medical staff use to support clinical decision making. There is still an urgent need to develop low-cost and unobtrusive mobile health monitoring systems. The goal of this study was twofold. Firstly, a wearable sensor system composed of plantar pressure insoles and wearable sensors for joint angle measurement was developed. Secondly, the accuracy of the system in the measurement of ground reaction forces and joint moments was examined. The measurements included joint angles and plantar pressure distribution. To validate the wearable sensor system and examine the effectiveness of the proposed method for gait analysis, an experimental study on ten volunteer subjects was conducted. The accuracy of measurement of ground reaction forces and joint moments was validated against the results obtained from a reference motion capture system. Ground reaction forces and joint moments measured by the wearable sensor system showed a root mean square error of 1% for min. GRF and 27.3% for knee extension moment. The correlation coefficient was over 0.9, in comparison with the stationary motion capture system. The study suggests that the wearable sensor system could be recommended both for research and clinical applications outside a typical gait laboratory.

  18. Sensor network based vehicle classification and license plate identification system

    Energy Technology Data Exchange (ETDEWEB)

    Frigo, Janette Rose [Los Alamos National Laboratory; Brennan, Sean M [Los Alamos National Laboratory; Rosten, Edward J [Los Alamos National Laboratory; Raby, Eric Y [Los Alamos National Laboratory; Kulathumani, Vinod K [WEST VIRGINIA UNIV.

    2009-01-01

    Typically, for energy efficiency and scalability purposes, sensor networks have been used in the context of environmental and traffic monitoring applications in which operations at the sensor level are not computationally intensive. But increasingly, sensor network applications require data and compute intensive sensors such video cameras and microphones. In this paper, we describe the design and implementation of two such systems: a vehicle classifier based on acoustic signals and a license plate identification system using a camera. The systems are implemented in an energy-efficient manner to the extent possible using commercially available hardware, the Mica motes and the Stargate platform. Our experience in designing these systems leads us to consider an alternate more flexible, modular, low-power mote architecture that uses a combination of FPGAs, specialized embedded processing units and sensor data acquisition systems.

  19. An Integrated Intrusion Detection Model of Cluster-Based Wireless Sensor Network.

    Science.gov (United States)

    Sun, Xuemei; Yan, Bo; Zhang, Xinzhong; Rong, Chuitian

    2015-01-01

    Considering wireless sensor network characteristics, this paper combines anomaly and mis-use detection and proposes an integrated detection model of cluster-based wireless sensor network, aiming at enhancing detection rate and reducing false rate. Adaboost algorithm with hierarchical structures is used for anomaly detection of sensor nodes, cluster-head nodes and Sink nodes. Cultural-Algorithm and Artificial-Fish-Swarm-Algorithm optimized Back Propagation is applied to mis-use detection of Sink node. Plenty of simulation demonstrates that this integrated model has a strong performance of intrusion detection.

  20. A general framework for sensor-based human activity recognition.

    Science.gov (United States)

    Köping, Lukas; Shirahama, Kimiaki; Grzegorzek, Marcin

    2018-04-01

    Today's wearable devices like smartphones, smartwatches and intelligent glasses collect a large amount of data from their built-in sensors like accelerometers and gyroscopes. These data can be used to identify a person's current activity and in turn can be utilised for applications in the field of personal fitness assistants or elderly care. However, developing such systems is subject to certain restrictions: (i) since more and more new sensors will be available in the future, activity recognition systems should be able to integrate these new sensors with a small amount of manual effort and (ii) such systems should avoid high acquisition costs for computational power. We propose a general framework that achieves an effective data integration based on the following two characteristics: Firstly, a smartphone is used to gather and temporally store data from different sensors and transfer these data to a central server. Thus, various sensors can be integrated into the system as long as they have programming interfaces to communicate with the smartphone. The second characteristic is a codebook-based feature learning approach that can encode data from each sensor into an effective feature vector only by tuning a few intuitive parameters. In the experiments, the framework is realised as a real-time activity recognition system that integrates eight sensors from a smartphone, smartwatch and smartglasses, and its effectiveness is validated from different perspectives such as accuracies, sensor combinations and sampling rates. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Nighttime Infrared radiative cooling and opacity inferred by REMS Ground Temperature Sensor Measurements

    Science.gov (United States)

    Martín-Torres, Javier; Paz Zorzano, María; Pla-García, Jorge; Rafkin, Scot; Lepinette, Alain; Sebastián, Eduardo; Gómez-Elvira, Javier; REMS Team

    2013-04-01

    Due to the low density of the Martian atmosphere, the temperature of the surface is controlled primarily by solar heating, and infrared cooling to the atmosphere and space, rather than heat exchange with the atmosphere. In the absence of solar radiation the infrared (IR) cooling, and then the nighttime surface temperatures, are directly controlled by soil termal inertia and atmospheric optical thickness (τ) at infrared wavelengths. Under non-wind conditions, and assuming no processes involving latent heat changes in the surface, for a particular site where the rover stands the main parameter controlling the IR cooling will be τ. The minimal ground temperature values at a fixed position may thus be used to detect local variations in the total dust/aerosols/cloud tickness. The Ground Temperature Sensor (GTS) and Air Temperature Sensor (ATS) in the Rover Environmental Monitoring Station (REMS) on board the Mars Science Laboratory (MSL) Curiosity rover provides hourly ground and air temperature measurements respectively. During the first 100 sols of operation of the rover, within the area of low thermal inertia, the minimal nightime ground temperatures reached values between 180 K and 190 K. For this season the expected frost point temperature is 200 K. Variations of up to 10 K have been observed associated with dust loading at Gale at the onset of the dust season. We will use these measurements together with line-by-line radiative transfer simulations using the Full Transfer By Optimized LINe-by-line (FUTBOLIN) code [Martín-Torres and Mlynczak, 2005] to estimate the IR atmospheric opacity and then dust/cloud coverage over the rover during the course of the MSL mission. Monitoring the dust loading and IR nightime cooling evolution during the dust season will allow for a better understanding of the influence of the atmosphere on the ground temperature and provide ground truth to models and orbiter measurements. References Martín-Torres, F. J. and M. G. Mlynczak

  2. Fuzzy-Based Sensor Fusion for Cognitive Radio-Based Vehicular Ad Hoc and Sensor Networks

    Directory of Open Access Journals (Sweden)

    Mohammad Jalil Piran

    2015-01-01

    Full Text Available In wireless sensor networks, sensor fusion is employed to integrate the acquired data from diverse sensors to provide a unified interpretation. The best and most salient advantage of sensor fusion is to obtain high-level information in both statistical and definitive aspects, which cannot be attained by a single sensor. In this paper, we propose a novel sensor fusion technique based on fuzzy theory for our earlier proposed Cognitive Radio-based Vehicular Ad Hoc and Sensor Networks (CR-VASNET. In the proposed technique, we considered four input sensor readings (antecedents and one output (consequent. The employed mobile nodes in CR-VASNET are supposed to be equipped with diverse sensors, which cater to our antecedent variables, for example, The Jerk, Collision Intensity, and Temperature and Inclination Degree. Crash_Severity is considered as the consequent variable. The processing and fusion of the diverse sensory signals are carried out by fuzzy logic scenario. Accuracy and reliability of the proposed protocol, demonstrated by the simulation results, introduce it as an applicable system to be employed to reduce the causalities rate of the vehicles’ crashes.

  3. Development of a dynamic web mapping service for vegetation productivity using earth observation and in situ sensors in a sensor web based approach

    NARCIS (Netherlands)

    Kooistra, L.; Bergsma, A.R.; Chuma, B.; Bruin, de S.

    2009-01-01

    This paper describes the development of a sensor web based approach which combines earth observation and in situ sensor data to derive typical information offered by a dynamic web mapping service (WMS). A prototype has been developed which provides daily maps of vegetation productivity for the

  4. Distributed cluster management techniques for unattended ground sensor networks

    Science.gov (United States)

    Essawy, Magdi A.; Stelzig, Chad A.; Bevington, James E.; Minor, Sharon

    2005-05-01

    Smart Sensor Networks are becoming important target detection and tracking tools. The challenging problems in such networks include the sensor fusion, data management and communication schemes. This work discusses techniques used to distribute sensor management and multi-target tracking responsibilities across an ad hoc, self-healing cluster of sensor nodes. Although miniaturized computing resources possess the ability to host complex tracking and data fusion algorithms, there still exist inherent bandwidth constraints on the RF channel. Therefore, special attention is placed on the reduction of node-to-node communications within the cluster by minimizing unsolicited messaging, and distributing the sensor fusion and tracking tasks onto local portions of the network. Several challenging problems are addressed in this work including track initialization and conflict resolution, track ownership handling, and communication control optimization. Emphasis is also placed on increasing the overall robustness of the sensor cluster through independent decision capabilities on all sensor nodes. Track initiation is performed using collaborative sensing within a neighborhood of sensor nodes, allowing each node to independently determine if initial track ownership should be assumed. This autonomous track initiation prevents the formation of duplicate tracks while eliminating the need for a central "management" node to assign tracking responsibilities. Track update is performed as an ownership node requests sensor reports from neighboring nodes based on track error covariance and the neighboring nodes geo-positional location. Track ownership is periodically recomputed using propagated track states to determine which sensing node provides the desired coverage characteristics. High fidelity multi-target simulation results are presented, indicating the distribution of sensor management and tracking capabilities to not only reduce communication bandwidth consumption, but to also

  5. ANALYSIS OF COMBINED UAV-BASED RGB AND THERMAL REMOTE SENSING DATA: A NEW APPROACH TO CROWD MONITORING

    Directory of Open Access Journals (Sweden)

    S. Schulte

    2017-08-01

    Full Text Available Collecting vast amount of data does not solely help to fulfil information needs related to crowd monitoring, it is rather important to collect data that is suitable to meet specific information requirements. In order to address this issue, a prototype is developed to facilitate the combination of UAV-based RGB and thermal remote sensing datasets. In an experimental approach, image sensors were mounted on a remotely piloted aircraft and captured two video datasets over a crowd. A group of volunteers performed diverse movements that depict real world scenarios. The prototype is deriving the movement on the ground and is programmed in MATLAB. This novel detection approach using combined data is afterwards evaluated against detection algorithms that only use a single data source. Our tests show that the combination of RGB and thermal remote sensing data is beneficial for the field of crowd monitoring regarding the detection of crowd movement.

  6. Fault diagnostics for turbo-shaft engine sensors based on a simplified on-board model.

    Science.gov (United States)

    Lu, Feng; Huang, Jinquan; Xing, Yaodong

    2012-01-01

    Combining a simplified on-board turbo-shaft model with sensor fault diagnostic logic, a model-based sensor fault diagnosis method is proposed. The existing fault diagnosis method for turbo-shaft engine key sensors is mainly based on a double redundancies technique, and this can't be satisfied in some occasions as lack of judgment. The simplified on-board model provides the analytical third channel against which the dual channel measurements are compared, while the hardware redundancy will increase the structure complexity and weight. The simplified turbo-shaft model contains the gas generator model and the power turbine model with loads, this is built up via dynamic parameters method. Sensor fault detection, diagnosis (FDD) logic is designed, and two types of sensor failures, such as the step faults and the drift faults, are simulated. When the discrepancy among the triplex channels exceeds a tolerance level, the fault diagnosis logic determines the cause of the difference. Through this approach, the sensor fault diagnosis system achieves the objectives of anomaly detection, sensor fault diagnosis and redundancy recovery. Finally, experiments on this method are carried out on a turbo-shaft engine, and two types of faults under different channel combinations are presented. The experimental results show that the proposed method for sensor fault diagnostics is efficient.

  7. Fault Diagnostics for Turbo-Shaft Engine Sensors Based on a Simplified On-Board Model

    Directory of Open Access Journals (Sweden)

    Yaodong Xing

    2012-08-01

    Full Text Available Combining a simplified on-board turbo-shaft model with sensor fault diagnostic logic, a model-based sensor fault diagnosis method is proposed. The existing fault diagnosis method for turbo-shaft engine key sensors is mainly based on a double redundancies technique, and this can’t be satisfied in some occasions as lack of judgment. The simplified on-board model provides the analytical third channel against which the dual channel measurements are compared, while the hardware redundancy will increase the structure complexity and weight. The simplified turbo-shaft model contains the gas generator model and the power turbine model with loads, this is built up via dynamic parameters method. Sensor fault detection, diagnosis (FDD logic is designed, and two types of sensor failures, such as the step faults and the drift faults, are simulated. When the discrepancy among the triplex channels exceeds a tolerance level, the fault diagnosis logic determines the cause of the difference. Through this approach, the sensor fault diagnosis system achieves the objectives of anomaly detection, sensor fault diagnosis and redundancy recovery. Finally, experiments on this method are carried out on a turbo-shaft engine, and two types of faults under different channel combinations are presented. The experimental results show that the proposed method for sensor fault diagnostics is efficient.

  8. Unattended Ground Sensors for Expeditionary Force 21 Intelligence Collections

    Science.gov (United States)

    2015-06-01

    little impact on modern intelligence collections. This thesis analyzes and compares the units and individual Marine skillsets that employ UGS, and the...the sensor employment planning cycle, and the socialization of this plan through the proper chain-of-command [4]. Figure 8 depicts the Sensor...the use of newly developed cellphone based technologies and emerging UGS capabilities to assist in Listening Post/ Observation Post (LP/OP

  9. Strategy of thunderstorm measurement with super dense ground-based observation network

    Science.gov (United States)

    Takahashi, Y.; Sato, M.

    2014-12-01

    It's not easy to understand the inside structure and developing process of thunderstorm only with existing meteorological instruments since its horizontal extent of the storm cell is sometimes smaller than an order of 10 km while one of the densest ground network in Japan, AMEDAS, consists of sites located every 17 km in average and the resolution of meteorological radar is 1-2 km in general. Even the X-band radar realizes the resolution of 250 m or larger. Here we suggest a new super dense observation network with simple and low cost sensors that can be used for measurement both of raindrop and vertical electric field change caused by cloud-to-ground lightning discharge. This sensor consists of two aluminum plates with a diameter of 10-20 cm. We carried out an observation campaign in summer of 2013 in the foothills of Mt. Yastugatake, Yamanashi and Nagano prefectures in Japan, installing 6 plate-type sensors at a distance of about 4 km. Horizontal location, height and charge amount of each lightning discharge are estimated successfully based on the information of electric field changes at several observing sites. Moreover, it was found that the thunderstorm has a very narrow structure well smaller than 300 m that cannot be measured by any other ways, counting the positive and negative pulses caused by attachment of raindrop to the sensor plate, respectively. We plan to construct a new super dense observation network in the north Kanto region, Japan, where the lightning activity is most prominent in summer Japan, distributing more than several tens of sensors at every 4 km or shorter, such as an order of 100 m at minimum. This kind of new type network will reveal the unknown fine structures of thunderstorms and open the door for constructing real time alert system of torrential rainfall and lightning stroke especially in the city area.

  10. A New Proxy Measurement Algorithm with Application to the Estimation of Vertical Ground Reaction Forces Using Wearable Sensors.

    Science.gov (United States)

    Guo, Yuzhu; Storm, Fabio; Zhao, Yifan; Billings, Stephen A; Pavic, Aleksandar; Mazzà, Claudia; Guo, Ling-Zhong

    2017-09-22

    Measurement of the ground reaction forces (GRF) during walking is typically limited to laboratory settings, and only short observations using wearable pressure insoles have been reported so far. In this study, a new proxy measurement method is proposed to estimate the vertical component of the GRF (vGRF) from wearable accelerometer signals. The accelerations are used as the proxy variable. An orthogonal forward regression algorithm (OFR) is employed to identify the dynamic relationships between the proxy variables and the measured vGRF using pressure-sensing insoles. The obtained model, which represents the connection between the proxy variable and the vGRF, is then used to predict the latter. The results have been validated using pressure insoles data collected from nine healthy individuals under two outdoor walking tasks in non-laboratory settings. The results show that the vGRFs can be reconstructed with high accuracy (with an average prediction error of less than 5.0%) using only one wearable sensor mounted at the waist (L5, fifth lumbar vertebra). Proxy measures with different sensor positions are also discussed. Results show that the waist acceleration-based proxy measurement is more stable with less inter-task and inter-subject variability than the proxy measures based on forehead level accelerations. The proposed proxy measure provides a promising low-cost method for monitoring ground reaction forces in real-life settings and introduces a novel generic approach for replacing the direct determination of difficult to measure variables in many applications.

  11. A New Proxy Measurement Algorithm with Application to the Estimation of Vertical Ground Reaction Forces Using Wearable Sensors

    Directory of Open Access Journals (Sweden)

    Yuzhu Guo

    2017-09-01

    Full Text Available Measurement of the ground reaction forces (GRF during walking is typically limited to laboratory settings, and only short observations using wearable pressure insoles have been reported so far. In this study, a new proxy measurement method is proposed to estimate the vertical component of the GRF (vGRF from wearable accelerometer signals. The accelerations are used as the proxy variable. An orthogonal forward regression algorithm (OFR is employed to identify the dynamic relationships between the proxy variables and the measured vGRF using pressure-sensing insoles. The obtained model, which represents the connection between the proxy variable and the vGRF, is then used to predict the latter. The results have been validated using pressure insoles data collected from nine healthy individuals under two outdoor walking tasks in non-laboratory settings. The results show that the vGRFs can be reconstructed with high accuracy (with an average prediction error of less than 5.0% using only one wearable sensor mounted at the waist (L5, fifth lumbar vertebra. Proxy measures with different sensor positions are also discussed. Results show that the waist acceleration-based proxy measurement is more stable with less inter-task and inter-subject variability than the proxy measures based on forehead level accelerations. The proposed proxy measure provides a promising low-cost method for monitoring ground reaction forces in real-life settings and introduces a novel generic approach for replacing the direct determination of difficult to measure variables in many applications.

  12. Autonomous Mission Operations for Sensor Webs

    Science.gov (United States)

    Underbrink, A.; Witt, K.; Stanley, J.; Mandl, D.

    2008-12-01

    We present interim results of a 2005 ROSES AIST project entitled, "Using Intelligent Agents to Form a Sensor Web for Autonomous Mission Operations", or SWAMO. The goal of the SWAMO project is to shift the control of spacecraft missions from a ground-based, centrally controlled architecture to a collaborative, distributed set of intelligent agents. The network of intelligent agents intends to reduce management requirements by utilizing model-based system prediction and autonomic model/agent collaboration. SWAMO agents are distributed throughout the Sensor Web environment, which may include multiple spacecraft, aircraft, ground systems, and ocean systems, as well as manned operations centers. The agents monitor and manage sensor platforms, Earth sensing systems, and Earth sensing models and processes. The SWAMO agents form a Sensor Web of agents via peer-to-peer coordination. Some of the intelligent agents are mobile and able to traverse between on-orbit and ground-based systems. Other agents in the network are responsible for encapsulating system models to perform prediction of future behavior of the modeled subsystems and components to which they are assigned. The software agents use semantic web technologies to enable improved information sharing among the operational entities of the Sensor Web. The semantics include ontological conceptualizations of the Sensor Web environment, plus conceptualizations of the SWAMO agents themselves. By conceptualizations of the agents, we mean knowledge of their state, operational capabilities, current operational capacities, Web Service search and discovery results, agent collaboration rules, etc. The need for ontological conceptualizations over the agents is to enable autonomous and autonomic operations of the Sensor Web. The SWAMO ontology enables automated decision making and responses to the dynamic Sensor Web environment and to end user science requests. The current ontology is compatible with Open Geospatial Consortium (OGC

  13. Coincident Observation of Lightning using Spaceborne Spectrophotometer and Ground-Level Electromagnetic Sensors

    Science.gov (United States)

    Adachi, Toru; Cohen, Morris; Li, Jingbo; Cummer, Steve; Blakeslee, Richard; Marshall, THomas; Stolzenberg, Maribeth; Karunarathne, Sumedhe; Hsu, Rue-Ron; Su, Han-Tzong; hide

    2012-01-01

    The present study aims at assessing a possible new way to reveal the properties of lightning flash, using spectrophotometric data obtained by FORMOSAT-2/ISUAL which is the first spaceborne multicolor lightning detector. The ISUAL data was analyzed in conjunction with ground ]based electromagnetic data obtained by Duke magnetic field sensors, NLDN, North Alabama Lightning Mapping Array (LMA), and Kennedy Space Center (KSC) electric field antennas. We first classified the observed events into cloud ]to ]ground (CG) and intra ]cloud (IC) lightning based on the Duke and NLDN measurements and analyzed ISUAL data to clarify their optical characteristics. It was found that the ISUAL optical waveform of CG lightning was strongly correlated with the current moment waveform, suggesting that it is possible to evaluate the electrical properties of lightning from satellite optical measurement to some extent. The ISUAL data also indicated that the color of CG lightning turned to red at the time of return stroke while the color of IC pulses remained unchanged. Furthermore, in one CG event which was simultaneously detected by ISUAL and LMA, the observed optical emissions slowly turned red as the altitude of optical source gradually decreased. All of these results indicate that the color of lightning flash depends on the source altitude and suggest that spaceborne optical measurement could be a new tool to discriminate CG and IC lightning. In the presentation, we will also show results on the comparison between the ISUAL and KSC electric field data to clarify characteristics of each lightning process such as preliminary breakdown, return stroke, and subsequent upward illumination.

  14. Alignment and Calibration of Optical and Inertial Sensors Using Stellar Observations

    National Research Council Canada - National Science Library

    Veth, Mike; Raquet, John

    2007-01-01

    Aircraft navigation information (position, velocity, and attitude) can be determined using optical measurements from an imaging sensor pointed toward the ground combined with an inertial navigation system...

  15. Cooperative Technique Based on Sensor Selection in Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    ISLAM, M. R.

    2009-02-01

    Full Text Available An energy efficient cooperative technique is proposed for the IEEE 1451 based Wireless Sensor Networks. Selected numbers of Wireless Transducer Interface Modules (WTIMs are used to form a Multiple Input Single Output (MISO structure wirelessly connected with a Network Capable Application Processor (NCAP. Energy efficiency and delay of the proposed architecture are derived for different combination of cluster size and selected number of WTIMs. Optimized constellation parameters are used for evaluating derived parameters. The results show that the selected MISO structure outperforms the unselected MISO structure and it shows energy efficient performance than SISO structure after a certain distance.

  16. (DCT-FY08) Target Detection Using Multiple Modality Airborne and Ground Based Sensors

    Science.gov (United States)

    2013-03-01

    resolution SIFT grids in metric-topological SLAM ,” in Proc. of the IEEE Conference on Computer Vision and Pattern Recognition, 2009. [4] M. Bosse and R...single camera SLAM ,” IEEE Trans. Pattern Anal. Mach. Intell., vol. 29, no. 6, pp. 1052–1067, 2007. [7] D. Nister, O. Naroditsky, and J. Bergen...segmentation with ground-based and airborne LIDAR range data,” in Proceedings of the Fourth International Symposium on 3D Data Processing

  17. Assessment of NASA airborne laser altimetry data using ground-based GPS data near Summit Station, Greenland

    Science.gov (United States)

    Brunt, Kelly M.; Hawley, Robert L.; Lutz, Eric R.; Studinger, Michael; Sonntag, John G.; Hofton, Michelle A.; Andrews, Lauren C.; Neumann, Thomas A.

    2017-03-01

    A series of NASA airborne lidars have been used in support of satellite laser altimetry missions. These airborne laser altimeters have been deployed for satellite instrument development, for spaceborne data validation, and to bridge the data gap between satellite missions. We used data from ground-based Global Positioning System (GPS) surveys of an 11 km long track near Summit Station, Greenland, to assess the surface-elevation bias and measurement precision of three airborne laser altimeters including the Airborne Topographic Mapper (ATM), the Land, Vegetation, and Ice Sensor (LVIS), and the Multiple Altimeter Beam Experimental Lidar (MABEL). Ground-based GPS data from the monthly ground-based traverses, which commenced in 2006, allowed for the assessment of nine airborne lidar surveys associated with ATM and LVIS between 2007 and 2016. Surface-elevation biases for these altimeters - over the flat, ice-sheet interior - are less than 0.12 m, while assessments of measurement precision are 0.09 m or better. Ground-based GPS positions determined both with and without differential post-processing techniques provided internally consistent solutions. Results from the analyses of ground-based and airborne data provide validation strategy guidance for the Ice, Cloud, and land Elevation Satellite 2 (ICESat-2) elevation and elevation-change data products.

  18. A Wildlife Monitoring System Based on Wireless Image Sensor Networks

    Directory of Open Access Journals (Sweden)

    Junguo Zhang

    2014-10-01

    Full Text Available Survival and development of wildlife sustains the balance and stability of the entire ecosystem. Wildlife monitoring can provide lots of information such as wildlife species, quantity, habits, quality of life and habitat conditions, to help researchers grasp the status and dynamics of wildlife resources, and to provide basis for the effective protection, sustainable use, and scientific management of wildlife resources. Wildlife monitoring is the foundation of wildlife protection and management. Wireless Sensor Networks (WSN technology has become the most popular technology in the field of information. With advance of the CMOS image sensor technology, wireless sensor networks combined with image sensors, namely Wireless Image Sensor Networks (WISN technology, has emerged as an alternative in monitoring applications. Monitoring wildlife is one of its most promising applications. In this paper, system architecture of the wildlife monitoring system based on the wireless image sensor networks was presented to overcome the shortcomings of the traditional monitoring methods. Specifically, some key issues including design of wireless image sensor nodes and software process design have been studied and presented. A self-powered rotatable wireless infrared image sensor node based on ARM and an aggregation node designed for large amounts of data were developed. In addition, their corresponding software was designed. The proposed system is able to monitor wildlife accurately, automatically, and remotely in all-weather condition, which lays foundations for applications of wireless image sensor networks in wildlife monitoring.

  19. Combining a Novel Computer Vision Sensor with a Cleaning Robot to Achieve Autonomous Pig House Cleaning

    DEFF Research Database (Denmark)

    Andersen, Nils Axel; Braithwaite, Ian David; Blanke, Mogens

    2005-01-01

    condition based cleaning. This paper describes how a novel sensor, developed for the purpose, and algorithms for classification and learning are combined with a commercial robot to obtain an autonomous system which meets the necessary quality attributes. These include features to make selective cleaning...

  20. Experimental on two sensors combination used in horizontal pipe gas-water two-phase flow

    International Nuclear Information System (INIS)

    Wu, Hao; Dong, Feng

    2014-01-01

    Gas-water two phase flow phenomenon widely exists in production and living and the measurement of it is meaningful. A new type of long-waist cone flow sensor has been designed to measure two-phase mass flow rate. Six rings structure of conductance probe is used to measure volume fraction and axial velocity. The calibration of them have been made. Two sensors have been combined in horizontal pipeline experiment to measure two-phase flow mass flow rate. Several model of gas-water two-phase flow has been discussed. The calculation errors of total mass flow rate measurement is less than 5% based on the revised homogeneous flow model

  1. Ground-based photo monitoring

    Science.gov (United States)

    Frederick C. Hall

    2000-01-01

    Ground-based photo monitoring is repeat photography using ground-based cameras to document change in vegetation or soil. Assume those installing the photo location will not be the ones re-photographing it. This requires a protocol that includes: (1) a map to locate the monitoring area, (2) another map diagramming the photographic layout, (3) type and make of film such...

  2. Application of a sensor array based on capillary-attached conductive gas sensors for odor identification

    International Nuclear Information System (INIS)

    Bahraminejad, Behzad; Basri, Shahnor; Isa, Maryam; Hambali, Zarida

    2010-01-01

    An electronic nose based on an array of capillary-attached conductive gas sensors was fabricated. The identification ability of the developed structure was investigated by employing different categories of simple and complex odor databases. Feature data sets were generated from the dynamic and steady state responses of the sensor array to the applied odor databases. Combinations of different feature extraction and classification methods were used to detect target gases. Validation of each technique was evaluated. Achievements of the study proved high classification rates of the fabricated e-nose in odor identification. It was indicated that gas identification is possible by applying the early selected portion of transient responses of the developed sensor array. The ability of the mentioned structure in analyzing gas mixtures was also investigated. The results presented high accuracy in the classification of gas mixtures

  3. An Ambulatory System for Gait Monitoring Based on Wireless Sensorized Insoles

    Science.gov (United States)

    González, Iván; Fontecha, Jesús; Hervás, Ramón; Bravo, José

    2015-01-01

    A new gait phase detection system for continuous monitoring based on wireless sensorized insoles is presented. The system can be used in gait analysis mobile applications, and it is designed for real-time demarcation of gait phases. The system employs pressure sensors to assess the force exerted by each foot during walking. A fuzzy rule-based inference algorithm is implemented on a smartphone and used to detect each of the gait phases based on the sensor signals. Additionally, to provide a solution that is insensitive to perturbations caused by non-walking activities, a probabilistic classifier is employed to discriminate walking forward from other low-level activities, such as turning, walking backwards, lateral walking, etc. The combination of these two algorithms constitutes the first approach towards a continuous gait assessment system, by means of the avoidance of non-walking influences. PMID:26184199

  4. An Ambulatory System for Gait Monitoring Based on Wireless Sensorized Insoles

    Directory of Open Access Journals (Sweden)

    Iván González

    2015-07-01

    Full Text Available A new gait phase detection system for continuous monitoring based on wireless sensorized insoles is presented. The system can be used in gait analysis mobile applications, and it is designed for real-time demarcation of gait phases. The system employs pressure sensors to assess the force exerted by each foot during walking. A fuzzy rule-based inference algorithm is implemented on a smartphone and used to detect each of the gait phases based on the sensor signals. Additionally, to provide a solution that is insensitive to perturbations caused by non-walking activities, a probabilistic classifier is employed to discriminate walking forward from other low-level activities, such as turning, walking backwards, lateral walking, etc. The combination of these two algorithms constitutes the first approach towards a continuous gait assessment system, by means of the avoidance of non-walking influences.

  5. Structure optimization of a grain impact piezoelectric sensor and its application for monitoring separation losses on tangential-axial combine harvesters.

    Science.gov (United States)

    Liang, Zhenwei; Li, Yaoming; Zhao, Zhan; Xu, Lizhang

    2015-01-14

    Grain separation losses is a key parameter to weigh the performance of combine harvesters, and also a dominant factor for automatically adjusting their major working parameters. The traditional separation losses monitoring method mainly rely on manual efforts, which require a high labor intensity. With recent advancements in sensor technology, electronics and computational processing power, this paper presents an indirect method for monitoring grain separation losses in tangential-axial combine harvesters in real-time. Firstly, we developed a mathematical monitoring model based on detailed comparative data analysis of different feeding quantities. Then, we developed a grain impact piezoelectric sensor utilizing a YT-5 piezoelectric ceramic as the sensing element, and a signal process circuit designed according to differences in voltage amplitude and rise time of collision signals. To improve the sensor performance, theoretical analysis was performed from a structural vibration point of view, and the optimal sensor structural has been selected. Grain collide experiments have shown that the sensor performance was greatly improved. Finally, we installed the sensor on a tangential-longitudinal axial combine harvester, and grain separation losses monitoring experiments were carried out in North China, which results have shown that the monitoring method was feasible, and the biggest measurement relative error was 4.63% when harvesting rice.

  6. Structure Optimization of a Grain Impact Piezoelectric Sensor and Its Application for Monitoring Separation Losses on Tangential-Axial Combine Harvesters

    Science.gov (United States)

    Liang, Zhenwei; Li, Yaoming; Zhao, Zhan; Xu, Lizhang

    2015-01-01

    Grain separation losses is a key parameter to weigh the performance of combine harvesters, and also a dominant factor for automatically adjusting their major working parameters. The traditional separation losses monitoring method mainly rely on manual efforts, which require a high labor intensity. With recent advancements in sensor technology, electronics and computational processing power, this paper presents an indirect method for monitoring grain separation losses in tangential-axial combine harvesters in real-time. Firstly, we developed a mathematical monitoring model based on detailed comparative data analysis of different feeding quantities. Then, we developed a grain impact piezoelectric sensor utilizing a YT-5 piezoelectric ceramic as the sensing element, and a signal process circuit designed according to differences in voltage amplitude and rise time of collision signals. To improve the sensor performance, theoretical analysis was performed from a structural vibration point of view, and the optimal sensor structural has been selected. Grain collide experiments have shown that the sensor performance was greatly improved. Finally, we installed the sensor on a tangential-longitudinal axial combine harvester, and grain separation losses monitoring experiments were carried out in North China, which results have shown that the monitoring method was feasible, and the biggest measurement relative error was 4.63% when harvesting rice. PMID:25594592

  7. Automatic Identification of Alpine Mass Movements by a Combination of Seismic and Infrasound Sensors

    Science.gov (United States)

    Hübl, Johannes; McArdell, Brian W.; Walter, Fabian

    2018-01-01

    The automatic detection and identification of alpine mass movements such as debris flows, debris floods, or landslides have been of increasing importance for devising mitigation measures in densely populated and intensively used alpine regions. Since these mass movements emit characteristic seismic and acoustic waves in the low-frequency range (<30 Hz), several approaches have already been developed for detection and warning systems based on these signals. However, a combination of the two methods, for improving detection probability and reducing false alarms, is still applied rarely. This paper presents an update and extension of a previously published approach for a detection and identification system based on a combination of seismic and infrasound sensors. Furthermore, this work evaluates the possible early warning times at several test sites and aims to analyze the seismic and infrasound spectral signature produced by different sediment-related mass movements to identify the process type and estimate the magnitude of the event. Thus, this study presents an initial method for estimating the peak discharge and total volume of debris flows based on infrasound data. Tests on several catchments show that this system can detect and identify mass movements in real time directly at the sensor site with high accuracy and a low false alarm ratio. PMID:29789449

  8. Automatic Identification of Alpine Mass Movements by a Combination of Seismic and Infrasound Sensors

    Directory of Open Access Journals (Sweden)

    Andreas Schimmel

    2018-05-01

    Full Text Available The automatic detection and identification of alpine mass movements such as debris flows, debris floods, or landslides have been of increasing importance for devising mitigation measures in densely populated and intensively used alpine regions. Since these mass movements emit characteristic seismic and acoustic waves in the low-frequency range (<30 Hz, several approaches have already been developed for detection and warning systems based on these signals. However, a combination of the two methods, for improving detection probability and reducing false alarms, is still applied rarely. This paper presents an update and extension of a previously published approach for a detection and identification system based on a combination of seismic and infrasound sensors. Furthermore, this work evaluates the possible early warning times at several test sites and aims to analyze the seismic and infrasound spectral signature produced by different sediment-related mass movements to identify the process type and estimate the magnitude of the event. Thus, this study presents an initial method for estimating the peak discharge and total volume of debris flows based on infrasound data. Tests on several catchments show that this system can detect and identify mass movements in real time directly at the sensor site with high accuracy and a low false alarm ratio.

  9. Rainfall measurement based on in-situ storm drainage flow sensors

    DEFF Research Database (Denmark)

    Ahm, Malte; Rasmussen, Michael Robdrup

    2017-01-01

    Data for adjustment of weather radar rainfall estimations are mostly obtained from rain gauge observations. However, the density of rain gauges is often very low. Yet in many urban catchments, runoff sensors are typically available which can measure the rainfall indirectly. By utilising these sen......Data for adjustment of weather radar rainfall estimations are mostly obtained from rain gauge observations. However, the density of rain gauges is often very low. Yet in many urban catchments, runoff sensors are typically available which can measure the rainfall indirectly. By utilising...... these sensors, it may be possible to improve the ground rainfall estimate, and thereby improve the quantitative precipitation estimation from weather radars for urban drainage applications. To test the hypothesis, this paper presents a rainfall measurement method based on flow rate measurements from well......-defined urban surfaces. This principle was used to design a runoff measurement system in a parking structure in Aalborg, Denmark, where it was evaluated against rain gauges. The measurements show that runoff measurements from well-defined urban surfaces perform just as well as rain gauges. This opens up...

  10. Case-Based Multi-Sensor Intrusion Detection

    Science.gov (United States)

    Schwartz, Daniel G.; Long, Jidong

    2009-08-01

    Multi-sensor intrusion detection systems (IDSs) combine the alerts raised by individual IDSs and possibly other kinds of devices such as firewalls and antivirus software. A critical issue in building a multi-sensor IDS is alert-correlation, i.e., determining which alerts are caused by the same attack. This paper explores a novel approach to alert correlation using case-based reasoning (CBR). Each case in the CBR system's library contains a pattern of alerts raised by some known attack type, together with the identity of the attack. Then during run time, the alert streams gleaned from the sensors are compared with the patterns in the cases, and a match indicates that the attack described by that case has occurred. For this purpose the design of a fast and accurate matching algorithm is imperative. Two such algorithms were explored: (i) the well-known Hungarian algorithm, and (ii) an order-preserving matching of our own device. Tests were conducted using the DARPA Grand Challenge Problem attack simulator. These showed that the both matching algorithms are effective in detecting attacks; but the Hungarian algorithm is inefficient; whereas the order-preserving one is very efficient, in fact runs in linear time.

  11. A Novel Particulate Matter 2.5 Sensor Based on Surface Acoustic Wave Technology

    Directory of Open Access Journals (Sweden)

    Jiuling Liu

    2018-01-01

    Full Text Available Design, fabrication and experiments of a miniature particulate matter (PM 2.5 sensor based on the surface acoustic wave (SAW technology were proposed. The sensor contains a virtual impactor (VI for particle separation, a thermophoretic precipitator (TP for PM2.5 capture and a SAW sensor chip for PM2.5 mass detection. The separation performance of the VI was evaluated by using the finite element method (FEM model and the PM2.5 deposition characteristic in the TP was obtained by analyzing the thermophoretic theory. Employing the coupling-of-modes (COM model, a low loss and high-quality SAW resonator was designed. By virtue of the micro electro mechanical system (MEMS technology and semiconductor technology, the SAW based PM2.5 sensor detecting probe was fabricated. Then, combining a dual-port SAW oscillator and an air sampler, the experimental platform was set up. Exposing the PM2.5 sensor to the polystyrene latex (PSL particles in a chamber, the sensor performance was evaluated. The results show that by detecting the PSL particles with a certain diameter of 2 μm, the response of the SAW based PM2.5 sensor is linear, and in accordance with the response of the light scattering based PM2.5 monitor. The developed SAW based PM2.5 sensor has great potential for the application of airborne particle detection.

  12. Ground Monitoring Neotropical Dry Forests: A Sensor Network for Forest and Microclimate Dynamics in Semi-Arid Environments (Enviro-Net°)

    Science.gov (United States)

    Rankine, C. J.; Sánchez-Azofeifa, G.

    2011-12-01

    In the face of unprecedented global change driven by anthropogenic pressure on natural systems it has become imperative to monitor and better understand potential shifts in ecosystem functioning and services from local to global scales. The utilization of automated sensors technologies offers numerous advantages over traditional on-site ecosystem surveying techniques and, as a result, sensor networks are becoming a powerful tool in environmental monitoring programs. Tropical forests, renowned for their biodiversity, are important regulators of land-atmosphere fluxes yet the seasonally dry tropical forests, which account for 40% of forested ecosystems in the American tropics, have been severely degraded over the past several decades and not much is known of their capacity to recover. With less than 1% of these forests protected, our ability to monitor the dynamics and quantify changes in the remaining primary and recovering secondary tropical dry forests is vital to understanding mechanisms of ecosystem stress responses and climate feedback with respect to annual productivity and desertification processes in the tropics. The remote sensing component of the Tropi-Dry: Human and Biophysical Dimensions of Tropical Dry Forests in the Americas research network supports a network of long-term tropical ecosystem monitoring platforms which focus on the dynamics of seasonally dry tropical forests in the Americas. With over 25 sensor station deployments operating across a latitudinal gradient in Mexico, Costa Rica, Brazil, and Argentina continuously collecting hyper-temporal sensory input based on standardized deployment parameters, this monitoring system is unique among tropical environments. Technologies used in the network include optical canopy phenology towers, understory wireless sensing networks, above and below ground microclimate stations, and digital cameras. Sensory data streams are uploaded to a cyber-infrastructure initiative, denominated Enviro-Net°, for data

  13. Optical Fiber Grating based Sensors

    DEFF Research Database (Denmark)

    Michelsen, Susanne

    2003-01-01

    In this thesis differenct optical fiber gratings are used for sensor purposes. If a fiber with a core concentricity error (CCE) is used, a directional dependent bend sensor can be produced. The CCE direction can be determined by means of diffraction. This makes it possible to produce long......-period gratings in a fiber with a CCE direction parallel or perpendicular to the writing direction. The maximal bending sensitivity is independent on the writing direction, but the detailed bending response is different in the two cases. A temperature and strain sensor, based on a long-period grating and two...... sampled gratings, was produced and investigated. It is based on the different temperature and strain response of these gratings. Both a transfer matrix method and an overlap calculation is performed to explain the sensor response. Another type of sensor is based on tuning and modulation of a laser...

  14. Evaluating detection and estimation capabilities of magnetometer-based vehicle sensors

    Science.gov (United States)

    Slater, David M.; Jacyna, Garry M.

    2013-05-01

    In an effort to secure the northern and southern United States borders, MITRE has been tasked with developing Modeling and Simulation (M&S) tools that accurately capture the mapping between algorithm-level Measures of Performance (MOP) and system-level Measures of Effectiveness (MOE) for current/future surveillance systems deployed by the the Customs and Border Protection Office of Technology Innovations and Acquisitions (OTIA). This analysis is part of a larger M&S undertaking. The focus is on two MOPs for magnetometer-based Unattended Ground Sensors (UGS). UGS are placed near roads to detect passing vehicles and estimate properties of the vehicle's trajectory such as bearing and speed. The first MOP considered is the probability of detection. We derive probabilities of detection for a network of sensors over an arbitrary number of observation periods and explore how the probability of detection changes when multiple sensors are employed. The performance of UGS is also evaluated based on the level of variance in the estimation of trajectory parameters. We derive the Cramer-Rao bounds for the variances of the estimated parameters in two cases: when no a priori information is known and when the parameters are assumed to be Gaussian with known variances. Sample results show that UGS perform significantly better in the latter case.

  15. MnNi-based spin valve sensors combining high thermal stability, small footprint and pTesla detectivities

    Science.gov (United States)

    Silva, Marília; Leitao, Diana C.; Cardoso, Susana; Freitas, Paulo

    2018-05-01

    Magnetoresistive sensors with high thermal robustness, low noise and high spatial resolution are the answer to a number of challenging applications. Spin valve sensors including MnNi as antiferromagnet layer provide higher exchange bias field and improved thermal stability. In this work, the influence of the buffer layer type (Ta, NiFeCr) and thickness on key sensor parameters (e.g. offset field, Hf) is investigated. A Ta buffer layer promotes a strong (111) texture which leads to a higher value of MR. In contrast, Hf is lower for NiFeCr buffer. Micrometric sensors display thermal noise levels of 1 nT/Hz1/2 and 571 pT/Hz1/2 for a sensor height (h) of 2 and 4 μm, respectively. The temperature dependence of MR and sensitivity is also addressed and compared with MnIr based spin valves. In this case, MR abruptly decreases after heating at 160°C (without magnetic field), contrary to MnNi-based spin valves, where only a 10% MR decrease (relative to the initial value) is seen at 275°C. Finally, to further decrease the noise levels and improve detectivity, MnNi spin-valves are deposited vertically, and connected in parallel and series (in-plane) to create a device with low resistance and high sensitivity. A field detection at thermal level of 346 pT/Hz1/2 is achieved for a device with a total of 300 SVs (4 vertical, 15 in series, 5 in parallel).

  16. Gas Sensors Based on Semiconducting Nanowire Field-Effect Transistors

    Directory of Open Access Journals (Sweden)

    Ping Feng

    2014-09-01

    Full Text Available One-dimensional semiconductor nanostructures are unique sensing materials for the fabrication of gas sensors. In this article, gas sensors based on semiconducting nanowire field-effect transistors (FETs are comprehensively reviewed. Individual nanowires or nanowire network films are usually used as the active detecting channels. In these sensors, a third electrode, which serves as the gate, is used to tune the carrier concentration of the nanowires to realize better sensing performance, including sensitivity, selectivity and response time, etc. The FET parameters can be modulated by the presence of the target gases and their change relate closely to the type and concentration of the gas molecules. In addition, extra controls such as metal decoration, local heating and light irradiation can be combined with the gate electrode to tune the nanowire channel and realize more effective gas sensing. With the help of micro-fabrication techniques, these sensors can be integrated into smart systems. Finally, some challenges for the future investigation and application of nanowire field-effect gas sensors are discussed.

  17. A software-based sensor for combined sewer overflows.

    Science.gov (United States)

    Leonhardt, G; Fach, S; Engelhard, C; Kinzel, H; Rauch, W

    2012-01-01

    A new methodology for online estimation of excess flow from combined sewer overflow (CSO) structures based on simulation models is presented. If sufficient flow and water level data from the sewer system is available, no rainfall data are needed to run the model. An inverse rainfall-runoff model was developed to simulate net rainfall based on flow and water level data. Excess flow at all CSO structures in a catchment can then be simulated with a rainfall-runoff model. The method is applied to a case study and results show that the inverse rainfall-runoff model can be used instead of missing rain gauges. Online operation is ensured by software providing an interface to the SCADA-system of the operator and controlling the model. A water quality model could be included to simulate also pollutant concentrations in the excess flow.

  18. A Manual Transportable Instrument Platform for Ground-Based Spectro-Directional Observations (ManTIS and the Resultant Hyperspectral Field Goniometer System

    Directory of Open Access Journals (Sweden)

    Marcel Buchhorn

    2013-11-01

    Full Text Available This article presents and technically describes a new field spectro-goniometer system for the ground-based characterization of the surface reflectance anisotropy under natural illumination conditions developed at the Alfred Wegener Institute (AWI. The spectro-goniometer consists of a Manual Transportable Instrument platform for ground-based Spectro-directional observations (ManTIS, and a hyperspectral sensor system. The presented measurement strategy shows that the AWI ManTIS field spectro-goniometer can deliver high quality hemispherical conical reflectance factor (HCRF measurements with a pointing accuracy of ±6 cm within the constant observation center. The sampling of a ManTIS hemisphere (up to 30° viewing zenith, 360° viewing azimuth needs approx. 18 min. The developed data processing chain in combination with the software used for the semi-automatic control provides a reliable method to reduce temporal effects during the measurements. The presented visualization and analysis approaches of the HCRF data of an Arctic low growing vegetation showcase prove the high quality of spectro-goniometer measurements. The patented low-cost and lightweight ManTIS instrument platform can be customized for various research needs and is available for purchase.

  19. CMOS image sensor-based implantable glucose sensor using glucose-responsive fluorescent hydrogel.

    Science.gov (United States)

    Tokuda, Takashi; Takahashi, Masayuki; Uejima, Kazuhiro; Masuda, Keita; Kawamura, Toshikazu; Ohta, Yasumi; Motoyama, Mayumi; Noda, Toshihiko; Sasagawa, Kiyotaka; Okitsu, Teru; Takeuchi, Shoji; Ohta, Jun

    2014-11-01

    A CMOS image sensor-based implantable glucose sensor based on an optical-sensing scheme is proposed and experimentally verified. A glucose-responsive fluorescent hydrogel is used as the mediator in the measurement scheme. The wired implantable glucose sensor was realized by integrating a CMOS image sensor, hydrogel, UV light emitting diodes, and an optical filter on a flexible polyimide substrate. Feasibility of the glucose sensor was verified by both in vitro and in vivo experiments.

  20. Recent Advances in Paper-Based Sensors

    Directory of Open Access Journals (Sweden)

    Edith Chow

    2012-08-01

    Full Text Available Paper-based sensors are a new alternative technology for fabricating simple, low-cost, portable and disposable analytical devices for many application areas including clinical diagnosis, food quality control and environmental monitoring. The unique properties of paper which allow passive liquid transport and compatibility with chemicals/biochemicals are the main advantages of using paper as a sensing platform. Depending on the main goal to be achieved in paper-based sensors, the fabrication methods and the analysis techniques can be tuned to fulfill the needs of the end-user. Current paper-based sensors are focused on microfluidic delivery of solution to the detection site whereas more advanced designs involve complex 3-D geometries based on the same microfluidic principles. Although paper-based sensors are very promising, they still suffer from certain limitations such as accuracy and sensitivity. However, it is anticipated that in the future, with advances in fabrication and analytical techniques, that there will be more new and innovative developments in paper-based sensors. These sensors could better meet the current objectives of a viable low-cost and portable device in addition to offering high sensitivity and selectivity, and multiple analyte discrimination. This paper is a review of recent advances in paper-based sensors and covers the following topics: existing fabrication techniques, analytical methods and application areas. Finally, the present challenges and future outlooks are discussed.

  1. Gold nanoparticle-based optical microfluidic sensors for analysis of environmental pollutants

    DEFF Research Database (Denmark)

    Lafleur, Josiane P.; Senkbeil, Silja; Jensen, Thomas G.

    2012-01-01

    Conventional methods of environmental analysis can be significantly improved by the development of portable microscale technologies for direct in-field sensing at remote locations. This report demonstrates the vast potential of gold nanoparticle-based microfluidic sensors for the rapid, in......-field, detection of two important classes of environmental contaminants – heavy metals and pesticides. Using gold nanoparticle-based microfluidic sensors linked to a simple digital camera as the detector, detection limits as low as 0.6 μg L−1 and 16 μg L−1 could be obtained for the heavy metal mercury...... and the dithiocarbamate pesticide ziram, respectively. These results demonstrate that the attractive optical properties of gold nanoparticle probes combine synergistically with the inherent qualities of microfluidic platforms to offer simple, portable and sensitive sensors for environmental contaminants....

  2. UV-sensitive optical sensors based on ITO-gallium phosphide heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Malik, Oleksandr; Hidalga-Wade, F. Javier de la; Zuniga-Islas, Carlos; Abundis Patino, Jesus H. [National Institute for Astrophysics, Optics, and Electronics (INAOE), Puebla (Mexico)

    2010-04-15

    Design and characteristics of wide-band UV sensors based on ITO/GaP heterostructures are discussed. Such sensors have perfect electrical parameters and high UV-visible sensitivity in comparison with surface-barrier structures using a semi-transparent thin metal film as an electrode. Many applications require UV sensors with an effective rejection of visible radiation and a wide temperature operating interval. For this aim, the theoretical modelling of extreme selective optical sensors with a double Ag/ITO thin film on the GaP surface, in which the thin silver film serves as a narrow bandpass filter at 320 nm, has been conducted. With this modelling the optimal thickness combination for the silver and ITO films was found for the maximum rejection of the sensitivity to visible radiation (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Selective hydrogen detection at high temperature by using yttria-stabilized zirconia-based sensor with coupled metal-oxide-based sensing electrodes

    International Nuclear Information System (INIS)

    Yamaguchi, Mami; Anggraini, Sri Ayu; Fujio, Yuki; Breedon, Michael; Plashnitsa, Vladimir V.; Miura, Norio

    2012-01-01

    A selective and sensitive hydrogen (H 2 ) sensor capable of working at a high operating temperature was developed by using a pair of metal-oxide-based SEs formed on a yttria-stabilized zirconia (YSZ) tube, operating as a mixed-potential type sensor. The utilization of SnO 2 (+30 wt.% YSZ) electrode together with NiO-TiO 2 electrode configured as a combined-type sensor, successfully diminished the response of the examined interfering gases (especially propene), while maintaining high response toward H 2 at an operating temperature of 600 °C under humid operating conditions. The developed sensor exhibited quick response to 100 ppm H 2 , as the 90% response time was observed to be 9 s. The sensing performance of the combined-type sensor was barely affected by changes in water vapor concentration within the range of 1–4 vol.%, suggesting the resilience of the sensor to function in realistic working conditions. This sensor exhibited a linear relationship between sensitivity and H 2 concentration on a logarithmic scale.

  4. Intercomparison of unmanned aerial vehicle and ground-based narrow band spectrometers applied to crop trait monitoring in organic potato production

    NARCIS (Netherlands)

    Domingues Franceschini, Marston; Bartholomeus, Harm; Apeldoorn, van Dirk; Suomalainen, Juha; Kooistra, Lammert

    2017-01-01

    Vegetation properties can be estimated using optical sensors, acquiring data on board of different platforms. For instance, ground-based and Unmanned Aerial Vehicle (UAV)-borne spectrometers can measure reflectance in narrow spectral bands, while different modelling approaches, like regressions

  5. Relational-Based Sensor Data Cleansing

    DEFF Research Database (Denmark)

    Iftikhar, Nadeem; Liu, Xiufeng; Nordbjerg, Finn Ebertsen

    2015-01-01

    cleansing approaches, such as classification, prediction and moving average are not suited for embedded sensor devices, due to the limited storage and processing capabilities. In this paper, we propose a sensor data cleansing approach using the relational-based technologies, including constraints, triggers...... and granularity-based data aggregation. The proposed approach is simple but effective to cleanse different types of dirty data, including delayed data, incomplete data, incorrect data, duplicate data and missing data. We evaluate the proposed strategy to verify its efficiency, effectiveness and adaptability.......Today sensors are widely used in many monitoring applications. Due to some random environmental effects and/or sensing failures, the collected sensor data is typically noisy. Thus, it is critical to cleanse the sensor data before using it to answer queries or conduct data analysis. Popular data...

  6. Networked sensors for the combat forces

    Science.gov (United States)

    Klager, Gene

    2004-11-01

    Real-time and detailed information is critical to the success of ground combat forces. Current manned reconnaissance, surveillance, and target acquisition (RSTA) capabilities are not sufficient to cover battlefield intelligence gaps, provide Beyond-Line-of-Sight (BLOS) targeting, and the ambush avoidance information necessary for combat forces operating in hostile situations, complex terrain, and conducting military operations in urban terrain. This paper describes a current US Army program developing advanced networked unmanned/unattended sensor systems to survey these gaps and provide the Commander with real-time, pertinent information. Networked Sensors for the Combat Forces plans to develop and demonstrate a new generation of low cost distributed unmanned sensor systems organic to the RSTA Element. Networked unmanned sensors will provide remote monitoring of gaps, will increase a unit"s area of coverage, and will provide the commander organic assets to complete his Battlefield Situational Awareness (BSA) picture for direct and indirect fire weapons, early warning, and threat avoidance. Current efforts include developing sensor packages for unmanned ground vehicles, small unmanned aerial vehicles, and unattended ground sensors using advanced sensor technologies. These sensors will be integrated with robust networked communications and Battle Command tools for mission planning, intelligence "reachback", and sensor data management. The network architecture design is based on a model that identifies a three-part modular design: 1) standardized sensor message protocols, 2) Sensor Data Management, and 3) Service Oriented Architecture. This simple model provides maximum flexibility for data exchange, information management and distribution. Products include: Sensor suites optimized for unmanned platforms, stationary and mobile versions of the Sensor Data Management Center, Battle Command planning tools, networked communications, and sensor management software. Details

  7. Chemical sensors based on surface charge transfer

    Science.gov (United States)

    Mohtasebi, Amirmasoud; Kruse, Peter

    2018-02-01

    The focus of this review is an introduction to chemiresistive chemical sensors. The general concept of chemical sensors is briefly introduced, followed by different architectures of chemiresistive sensors and relevant materials. For several of the most common systems, the fabrication of the active materials used in such sensors and their properties are discussed. Furthermore, the sensing mechanism, advantages, and limitations of each group of chemiresistive sensors are briefly elaborated. Compared to electrochemical sensors, chemiresistive sensors have the key advantage of a simpler geometry, eliminating the need for a reference electrode. The performance of bulk chemiresistors can be improved upon by using freestanding ultra-thin films (nanomaterials) or field effect geometries. Both of those concepts have also been combined in a gateless geometry, where charge transport though a percolation network of nanomaterials is modulated via adsorbate doping.

  8. Exploring the impact of big data in economic geology using cloud-based synthetic sensor networks

    Science.gov (United States)

    Klump, J. F.; Robertson, J.

    2015-12-01

    In a market demanding lower resource prices and increasing efficiencies, resources companies are increasingly looking to the realm of real-time, high-frequency data streams to better measure and manage their minerals processing chain, from pit to plant to port. Sensor streams can include real-time drilling engineering information, data streams from mining trucks, and on-stream sensors operating in the plant feeding back rich chemical information. There are also many opportunities to deploy new sensor streams - unlike environmental monitoring networks, the mine environment is not energy- or bandwidth-limited. Although the promised efficiency dividends are inviting, the path to achieving these is difficult to see for most companies. As well as knowing where to invest in new sensor technology and how to integrate the new data streams, companies must grapple with risk-laden changes to their established methods of control to achieve maximum gains. What is required is a sandbox data environment for the development of analysis and control strategies at scale, allowing companies to de-risk proposed changes before actually deploying them to a live mine environment. In this presentation we describe our approach to simulating real-time scaleable data streams in a mine environment. Our sandbox consists of three layers: (a) a ground-truth layer that contains geological models, which can be statistically based on historical operations data, (b) a measurement layer - a network of RESTful synthetic sensor microservices which can simulate measurements of ground-truth properties, and (c) a control layer, which integrates the sensor streams and drives the measurement and optimisation strategies. The control layer could be a new machine learner, or simply a company's existing data infrastructure. Containerisation allows rapid deployment of large numbers of sensors, as well as service discovery to form a dynamic network of thousands of sensors, at a far lower cost than physically

  9. Iron-Based Nanomaterials/Graphene Composites for Advanced Electrochemical Sensors

    Directory of Open Access Journals (Sweden)

    Kaveh Movlaee

    2017-11-01

    Full Text Available Iron oxide nanostructures (IONs in combination with graphene or its derivatives—e.g., graphene oxide and reduced graphene oxide—hold great promise toward engineering of efficient nanocomposites for enhancing the performance of advanced devices in many applicative fields. Due to the peculiar electrical and electrocatalytic properties displayed by composite structures in nanoscale dimensions, increasing efforts have been directed in recent years toward tailoring the properties of IONs-graphene based nanocomposites for developing more efficient electrochemical sensors. In the present feature paper, we first reviewed the various routes for synthesizing IONs-graphene nanostructures, highlighting advantages, disadvantages and the key synthesis parameters for each method. Then, a comprehensive discussion is presented in the case of application of IONs-graphene based composites in electrochemical sensors for the determination of various kinds of (biochemical substances.

  10. Iron-Based Nanomaterials/Graphene Composites for Advanced Electrochemical Sensors

    Science.gov (United States)

    Movlaee, Kaveh; Ganjali, Mohmmad Reza; Norouzi, Parviz

    2017-01-01

    Iron oxide nanostructures (IONs) in combination with graphene or its derivatives—e.g., graphene oxide and reduced graphene oxide—hold great promise toward engineering of efficient nanocomposites for enhancing the performance of advanced devices in many applicative fields. Due to the peculiar electrical and electrocatalytic properties displayed by composite structures in nanoscale dimensions, increasing efforts have been directed in recent years toward tailoring the properties of IONs-graphene based nanocomposites for developing more efficient electrochemical sensors. In the present feature paper, we first reviewed the various routes for synthesizing IONs-graphene nanostructures, highlighting advantages, disadvantages and the key synthesis parameters for each method. Then, a comprehensive discussion is presented in the case of application of IONs-graphene based composites in electrochemical sensors for the determination of various kinds of (bio)chemical substances. PMID:29168771

  11. Performance of an Advanced Stirling Convertor Based on Heat Flux Sensor Measurements

    Science.gov (United States)

    Wilson, Dcott D.

    2012-01-01

    The U.S. Department of Energy (DOE) and Lockheed Martin Space Systems Company (LMSSC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. This generator would use two highefficiency Advanced Stirling Convertors (ASCs), developed by Sunpower, Inc., and NASA Glenn Research Center. The ASCs convert thermal energy from a radioisotope heat source into electricity. As part of ground testing of these ASCs, different operating conditions are used to simulate expected mission conditions. These conditions require achieving a particular operating frequency, hot-end and cold-end temperatures, and specified electrical power output for a given heat input. It is difficult to measure heat input to Stirling convertors due to the complex geometries of the hot components, temperature limits of sensor materials, and invasive integration of sensors. A thin-film heat flux sensor was used to directly measure heat input to an ASC. The effort succeeded in designing and fabricating unique sensors, which were integrated into a Stirling convertor ground test and exposed to test temperatures exceeding 700 C in air for 10,000 hr. Sensor measurements were used to calculate thermal efficiency for ASC-E (Engineering Unit) #1 and #4. The post-disassembly condition of the sensors is also discussed.

  12. All-plastic fiber-based pressure sensor

    DEFF Research Database (Denmark)

    Bundalo, Ivan-Lazar; Lwin, Richard; Leon-Saval, Sergio

    2016-01-01

    We present a feasibility study and a prototype of an all-plastic fiber-based pressure sensor. The sensor is based on long period gratings inscribed for the first time to the best of our knowledge by a CO2 laser in polymethyl methacrylate (PMMA) microstructured fibers and coupled to a pod......-like transducer that converts pressure to strain. The sensor prototype was characterized for pressures up to 150 mbars, and various parameters related to its construction were also characterized in order to enhance sensitivity. We consider this sensor in the context of future applications in endoscopic pressure...... sensors....

  13. Helicopter-borne observations of the continental background aerosol in combination with remote sensing and ground-based measurements

    Science.gov (United States)

    Düsing, Sebastian; Wehner, Birgit; Seifert, Patric; Ansmann, Albert; Baars, Holger; Ditas, Florian; Henning, Silvia; Ma, Nan; Poulain, Laurent; Siebert, Holger; Wiedensohler, Alfred; Macke, Andreas

    2018-01-01

    This paper examines the representativeness of ground-based in situ measurements for the planetary boundary layer (PBL) and conducts a closure study between airborne in situ and ground-based lidar measurements up to an altitude of 2300 m. The related measurements were carried out in a field campaign within the framework of the High-Definition Clouds and Precipitation for Advancing Climate Prediction (HD(CP)2) Observational Prototype Experiment (HOPE) in September 2013 in a rural background area of central Europe.The helicopter-borne probe ACTOS (Airborne Cloud and Turbulence Observation System) provided measurements of the aerosol particle number size distribution (PNSD), the aerosol particle number concentration (PNC), the number concentration of cloud condensation nuclei (CCN-NC), and meteorological atmospheric parameters (e.g., temperature and relative humidity). These measurements were supported by the ground-based 3+2 wavelength polarization lidar system PollyXT, which provided profiles of the particle backscatter coefficient (σbsc) for three wavelengths (355, 532, and 1064 nm). Particle extinction coefficient (σext) profiles were obtained by using a fixed backscatter-to-extinction ratio (also lidar ratio, LR). A new approach was used to determine profiles of CCN-NC for continental aerosol. The results of this new approach were consistent with the airborne in situ measurements within the uncertainties.In terms of representativeness, the PNSD measurements on the ground showed a good agreement with the measurements provided with ACTOS for lower altitudes. The ground-based measurements of PNC and CCN-NC are representative of the PBL when the PBL is well mixed. Locally isolated new particle formation events on the ground or at the top of the PBL led to vertical variability in the cases presented here and ground-based measurements are not entirely representative of the PBL. Based on Mie theory (Mie, 1908), optical aerosol properties under ambient conditions for

  14. Helicopter-borne observations of the continental background aerosol in combination with remote sensing and ground-based measurements

    Directory of Open Access Journals (Sweden)

    S. Düsing

    2018-01-01

    Full Text Available This paper examines the representativeness of ground-based in situ measurements for the planetary boundary layer (PBL and conducts a closure study between airborne in situ and ground-based lidar measurements up to an altitude of 2300 m. The related measurements were carried out in a field campaign within the framework of the High-Definition Clouds and Precipitation for Advancing Climate Prediction (HD(CP2 Observational Prototype Experiment (HOPE in September 2013 in a rural background area of central Europe.The helicopter-borne probe ACTOS (Airborne Cloud and Turbulence Observation System provided measurements of the aerosol particle number size distribution (PNSD, the aerosol particle number concentration (PNC, the number concentration of cloud condensation nuclei (CCN-NC, and meteorological atmospheric parameters (e.g., temperature and relative humidity. These measurements were supported by the ground-based 3+2 wavelength polarization lidar system PollyXT, which provided profiles of the particle backscatter coefficient (σbsc for three wavelengths (355, 532, and 1064 nm. Particle extinction coefficient (σext profiles were obtained by using a fixed backscatter-to-extinction ratio (also lidar ratio, LR. A new approach was used to determine profiles of CCN-NC for continental aerosol. The results of this new approach were consistent with the airborne in situ measurements within the uncertainties.In terms of representativeness, the PNSD measurements on the ground showed a good agreement with the measurements provided with ACTOS for lower altitudes. The ground-based measurements of PNC and CCN-NC are representative of the PBL when the PBL is well mixed. Locally isolated new particle formation events on the ground or at the top of the PBL led to vertical variability in the cases presented here and ground-based measurements are not entirely representative of the PBL. Based on Mie theory (Mie, 1908, optical aerosol properties under ambient

  15. Non-contact translation-rotation sensor using combined effects of magnetostriction and piezoelectricity.

    Science.gov (United States)

    Yang, Bintang; Liu, Qingwei; Zhang, Ting; Cao, Yudong; Feng, Zhiqiang; Meng, Guang

    2012-10-15

    Precise displacement sensors are an important topic in precision engineering. At present, this type of sensors typically have a single feature of either translation or rotation measurement. They are also inconvenient to integrate with the host devices. In this report we propose a new kind of sensor that enables both translation and rotation measurement by using the combined effect of magnetostriction and piezoelectricity. As a proof of concept, we experimentally realized a prototype of non-contact translation-rotation precise sensor. In the current research stage, through both theoretical and experimental study, the non-contact displacement sensor is shown to be feasible for measuring both translation and rotation either in coarse or fine measurement. Moreover, owing to its compact, rigid structure and fewer components, it can be easily embedded in host equipment.

  16. Non-Contact Translation-Rotation Sensor Using Combined Effects of Magnetostriction and Piezoelectricity

    Directory of Open Access Journals (Sweden)

    Guang Meng

    2012-10-01

    Full Text Available Precise displacement sensors are an important topic in precision engineering. At present, this type of sensors typically have a single feature of either translation or rotation measurement. They are also inconvenient to integrate with the host devices. In this report we propose a new kind of sensor that enables both translation and rotation measurement by using the combined effect of magnetostriction and piezoelectricity. As a proof of concept, we experimentally realized a prototype of non-contact translation-rotation precise sensor. In the current research stage, through both theoretical and experimental study, the non-contact displacement sensor is shown to be feasible for measuring both translation and rotation either in coarse or fine measurement. Moreover, owing to its compact, rigid structure and fewer components, it can be easily embedded in host equipment.

  17. Generation of Ground Truth Datasets for the Analysis of 3d Point Clouds in Urban Scenes Acquired via Different Sensors

    Science.gov (United States)

    Xu, Y.; Sun, Z.; Boerner, R.; Koch, T.; Hoegner, L.; Stilla, U.

    2018-04-01

    In this work, we report a novel way of generating ground truth dataset for analyzing point cloud from different sensors and the validation of algorithms. Instead of directly labeling large amount of 3D points requiring time consuming manual work, a multi-resolution 3D voxel grid for the testing site is generated. Then, with the help of a set of basic labeled points from the reference dataset, we can generate a 3D labeled space of the entire testing site with different resolutions. Specifically, an octree-based voxel structure is applied to voxelize the annotated reference point cloud, by which all the points are organized by 3D grids of multi-resolutions. When automatically annotating the new testing point clouds, a voting based approach is adopted to the labeled points within multiple resolution voxels, in order to assign a semantic label to the 3D space represented by the voxel. Lastly, robust line- and plane-based fast registration methods are developed for aligning point clouds obtained via various sensors. Benefiting from the labeled 3D spatial information, we can easily create new annotated 3D point clouds of different sensors of the same scene directly by considering the corresponding labels of 3D space the points located, which would be convenient for the validation and evaluation of algorithms related to point cloud interpretation and semantic segmentation.

  18. SMA-Based System for Environmental Sensors Released from an Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Lorenzo Pellone

    2017-01-01

    Full Text Available In the work at hand, a shape memory alloy (SMA-based system is presented. The system, conceived for releasing environmental sensors from ground or small unmanned aerial vehicles, UAV (often named UAS, unmanned aerial system, is made of a door, integrated into the bottom of the fuselage, a device distributor, operated by a couple of antagonistic SMA springs, and a kinematic chain, to synchronize the deployment operation with the system movement. On the basis of the specifications (weight, available space, energy supply, sensors size, etc., the system design was addressed. After having identified the main system characteristics, a representative mock-up was manufactured, featuring the bottom part of the reference fuselage. Functionality tests were performed to prove the system capability to release the sensors; a detailed characterization was finally carried out, mainly finalized at correlating the kinematic chain displacement with the SMA spring temperature and the supplied electrical power. A comparison between theoretical predictions and experimental outcomes showed good agreement.

  19. Gas Sensors Based on Electrodeposited Polymers

    Directory of Open Access Journals (Sweden)

    Boris Lakard

    2015-07-01

    Full Text Available Electrochemically deposited polymers, also called “synthetic metals”, have emerged as potential candidates for chemical sensing due to their interesting and tunable chemical, electrical, and structural properties. In particular, most of these polymers (including polypyrrole, polyaniline, polythiophene and their derivatives can be used as the sensitive layer of conductimetric gas sensors because of their conducting properties. An important advantage of polymer-based gas sensors is their efficiency at room temperature. This characteristic is interesting since most of the commercially-available sensors, usually based on metal oxides, work at high temperatures (300–400 °C. Consequently, polymer-based gas sensors are playing a growing role in the improvement of public health and environment control because they can lead to gas sensors operating with rapid detection, high sensitivity, small size, and specificity in atmospheric conditions. In this review, the recent advances in electrodeposited polymer-based gas sensors are summarized and discussed. It is shown that the sensing characteristics of electrodeposited polymers can be improved by chemical functionalization, nanostructuration, or mixing with other functional materials to form composites or hybrid materials.

  20. Model-Based Method for Sensor Validation

    Science.gov (United States)

    Vatan, Farrokh

    2012-01-01

    Fault detection, diagnosis, and prognosis are essential tasks in the operation of autonomous spacecraft, instruments, and in situ platforms. One of NASA s key mission requirements is robust state estimation. Sensing, using a wide range of sensors and sensor fusion approaches, plays a central role in robust state estimation, and there is a need to diagnose sensor failure as well as component failure. Sensor validation can be considered to be part of the larger effort of improving reliability and safety. The standard methods for solving the sensor validation problem are based on probabilistic analysis of the system, from which the method based on Bayesian networks is most popular. Therefore, these methods can only predict the most probable faulty sensors, which are subject to the initial probabilities defined for the failures. The method developed in this work is based on a model-based approach and provides the faulty sensors (if any), which can be logically inferred from the model of the system and the sensor readings (observations). The method is also more suitable for the systems when it is hard, or even impossible, to find the probability functions of the system. The method starts by a new mathematical description of the problem and develops a very efficient and systematic algorithm for its solution. The method builds on the concepts of analytical redundant relations (ARRs).

  1. Autonomous Sensors for Large Scale Data Collection

    Science.gov (United States)

    Noto, J.; Kerr, R.; Riccobono, J.; Kapali, S.; Migliozzi, M. A.; Goenka, C.

    2017-12-01

    Presented here is a novel implementation of a "Doppler imager" which remotely measures winds and temperatures of the neutral background atmosphere at ionospheric altitudes of 87-300Km and possibly above. Incorporating both recent optical manufacturing developments, modern network awareness and the application of machine learning techniques for intelligent self-monitoring and data classification. This system achieves cost savings in manufacturing, deployment and lifetime operating costs. Deployed in both ground and space-based modalities, this cost-disruptive technology will allow computer models of, ionospheric variability and other space weather models to operate with higher precision. Other sensors can be folded into the data collection and analysis architecture easily creating autonomous virtual observatories. A prototype version of this sensor has recently been deployed in Trivandrum India for the Indian Government. This Doppler imager is capable of operation, even within the restricted CubeSat environment. The CubeSat bus offers a very challenging environment, even for small instruments. The lack of SWaP and the challenging thermal environment demand development of a new generation of instruments; the Doppler imager presented is well suited to this environment. Concurrent with this CubeSat development is the development and construction of ground based arrays of inexpensive sensors using the proposed technology. This instrument could be flown inexpensively on one or more CubeSats to provide valuable data to space weather forecasters and ionospheric scientists. Arrays of magnetometers have been deployed for the last 20 years [Alabi, 2005]. Other examples of ground based arrays include an array of white-light all sky imagers (THEMIS) deployed across Canada [Donovan et al., 2006], oceans sensors on buoys [McPhaden et al., 2010], and arrays of seismic sensors [Schweitzer et al., 2002]. A comparable array of Doppler imagers can be constructed and deployed on the

  2. Combining wireless sensor networks and semantic middleware for an Internet of Things-based sportsman/woman monitoring application.

    Science.gov (United States)

    Rodríguez-Molina, Jesús; Martínez, José-Fernán; Castillejo, Pedro; López, Lourdes

    2013-01-31

    Wireless Sensor Networks (WSNs) are spearheading the efforts taken to build and deploy systems aiming to accomplish the ultimate objectives of the Internet of Things. Due to the sensors WSNs nodes are provided with, and to their ubiquity and pervasive capabilities, these networks become extremely suitable for many applications that so-called conventional cabled or wireless networks are unable to handle. One of these still underdeveloped applications is monitoring physical parameters on a person. This is an especially interesting application regarding their age or activity, for any detected hazardous parameter can be notified not only to the monitored person as a warning, but also to any third party that may be helpful under critical circumstances, such as relatives or healthcare centers. We propose a system built to monitor a sportsman/woman during a workout session or performing a sport-related indoor activity. Sensors have been deployed by means of several nodes acting as the nodes of a WSN, along with a semantic middleware development used for hardware complexity abstraction purposes. The data extracted from the environment, combined with the information obtained from the user, will compose the basis of the services that can be obtained.

  3. Combining Wireless Sensor Networks and Semantic Middleware for an Internet of Things-Based Sportsman/Woman Monitoring Application

    Science.gov (United States)

    Rodríguez-Molina, Jesús; Martínez, José-Fernán; Castillejo, Pedro; López, Lourdes

    2013-01-01

    Wireless Sensor Networks (WSNs) are spearheading the efforts taken to build and deploy systems aiming to accomplish the ultimate objectives of the Internet of Things. Due to the sensors WSNs nodes are provided with, and to their ubiquity and pervasive capabilities, these networks become extremely suitable for many applications that so-called conventional cabled or wireless networks are unable to handle. One of these still underdeveloped applications is monitoring physical parameters on a person. This is an especially interesting application regarding their age or activity, for any detected hazardous parameter can be notified not only to the monitored person as a warning, but also to any third party that may be helpful under critical circumstances, such as relatives or healthcare centers. We propose a system built to monitor a sportsman/woman during a workout session or performing a sport-related indoor activity. Sensors have been deployed by means of several nodes acting as the nodes of a WSN, along with a semantic middleware development used for hardware complexity abstraction purposes. The data extracted from the environment, combined with the information obtained from the user, will compose the basis of the services that can be obtained. PMID:23385405

  4. Combining Wireless Sensor Networks and Semantic Middleware for an Internet of Things-Based Sportsman/Woman Monitoring Application

    Directory of Open Access Journals (Sweden)

    Lourdes López

    2013-01-01

    Full Text Available Wireless Sensor Networks (WSNs are spearheading the efforts taken to build and deploy systems aiming to accomplish the ultimate objectives of the Internet of Things. Due to the sensors WSNs nodes are provided with, and to their ubiquity and pervasive capabilities, these networks become extremely suitable for many applications that so-called conventional cabled or wireless networks are unable to handle. One of these still underdeveloped applications is monitoring physical parameters on a person. This is an especially interesting application regarding their age or activity, for any detected hazardous parameter can be notified not only to the monitored person as a warning, but also to any third party that may be helpful under critical circumstances, such as relatives or healthcare centers. We propose a system built to monitor a sportsman/woman during a workout session or performing a sport-related indoor activity. Sensors have been deployed by means of several nodes acting as the nodes of a WSN, along with a semantic middleware development used for hardware complexity abstraction purposes. The data extracted from the environment, combined with the information obtained from the user, will compose the basis of the services that can be obtained.

  5. Microwave Metamaterial-Based Sensor for Dielectric Characterization of Liquids.

    Science.gov (United States)

    Soffiatti, André; Max, Yuri; G Silva, Sandro; M de Mendonça, Laércio

    2018-05-11

    This article proposed to build a system founded on metamaterial sensor antennas, which can be used to evaluate impurities in aqueous substances according to the quality of transmission between the sensor antennas. In order to do this, a dedicated setup with tests in several frequencies was deployed so as to monitor the behavior of transmission variation between sensors. These sensors are microstrip antennas with a ground plane of resonant cleaved metallic rings; the substrate functions as a metamaterial for the irradiating element. In this study, an analysis was made of transmission between the sensors, looking for variation in angles of incidence of signal and of distance between the antennas. The sensor was tested at various operating frequencies, as such 1.8 GHz, 2.4 GHz, 3.4 GHz and 4.1 GHz, resulting in different values of sensitivity. The prototypes were constructed and tested so as to analyze the dielectric effects of the impurities on NaCl and C₂H₄O₂ substances. The research aims to use these control systems of impurities in industrial premises.

  6. Biosensors for EVA: Improved Instrumentation for Ground-based Studies

    Science.gov (United States)

    Soller, B.; Ellerby, G.; Zou, F.; Scott, P.; Jin, C.; Lee, S. M. C.; Coates, J.

    2010-01-01

    During lunar excursions in the EVA suit, real-time measurement of metabolic rate is required to manage consumables and guide activities to ensure safe return to the base. Metabolic rate, or oxygen consumption (VO2), is normally measured from pulmonary parameters but cannot be determined with standard techniques in the oxygen-rich environment of a spacesuit. Our group has developed novel near infrared spectroscopic (NIRS) methods to calculate muscle oxygen saturation (SmO 2), hematocrit, and pH, and we recently demonstrated that we can use our NIRS sensor to measure VO 2 on the leg during cycling. Our NSBRI project has 4 objectives: (1) increase the accuracy of the metabolic rate calculation through improved prediction of stroke volume; (2) investigate the relative contributions of calf and thigh oxygen consumption to metabolic rate calculation for walking and running; (3) demonstrate that the NIRS-based noninvasive metabolic rate methodology is sensitive enough to detect decrement in VO 2 in a space analog; and (4) improve instrumentation to allow testing within a spacesuit. Over the past year we have made progress on all four objectives, but the most significant progress was made in improving the instrumentation. The NIRS system currently in use at JSC is based on fiber optics technology. Optical fiber bundles are used to deliver light from a light source in the monitor to the patient, and light reflected back from the patient s muscle to the monitor for spectroscopic analysis. The fiber optic cables are large and fragile, and there is no way to get them in and out of the test spacesuit used for ground-based studies. With complimentary funding from the US Army, we undertook a complete redesign of the sensor and control electronics to build a novel system small enough to be used within the spacesuit and portable enough to be used by a combat medic. In the new system the filament lamp used in the fiber optic system was replaced with a novel broadband near infrared

  7. Distributed sensor management for space situational awareness via a negotiation game

    Science.gov (United States)

    Jia, Bin; Shen, Dan; Pham, Khanh; Blasch, Erik; Chen, Genshe

    2015-05-01

    Space situational awareness (SSA) is critical to many space missions serving weather analysis, communications, and navigation. However, the number of sensors used in space situational awareness is limited which hinders collision avoidance prediction, debris assessment, and efficient routing. Hence, it is critical to use such sensor resources efficiently. In addition, it is desired to develop the SSA sensor management algorithm in a distributed manner. In this paper, a distributed sensor management approach using the negotiation game (NG-DSM) is proposed for the SSA. Specifically, the proposed negotiation game is played by each sensor and its neighboring sensors. The bargaining strategies are developed for each sensor based on negotiating for accurately tracking desired targets (e.g., satellite, debris, etc.) . The proposed NG-DSM method is tested in a scenario which includes eight space objects and three different sensor modalities which include a space based optical sensor, a ground radar, or a ground Electro-Optic sensor. The geometric relation between the sensor, the Sun, and the space object is also considered. The simulation results demonstrate the effectiveness of the proposed NG-DSM sensor management methods, which facilitates an application of multiple-sensor multiple-target tracking for space situational awareness.

  8. Performance of UWB Array-Based Radar Sensor in a Multi-Sensor Vehicle-Based Suit for Landmine Detection

    NARCIS (Netherlands)

    Yarovoy, A.; Savelyev, T.; Zhuge, X.; Aubry, P.; Ligthart, L.; Schavemaker, J.G.M.; Tettelaar, P.; Breejen, E. de

    2008-01-01

    In this paper, integration of an UWB array-based timedomain radar sensor in a vehicle-mounted multi-sensor system for landmine detection is described. Dedicated real-time signal processing algorithms are developed to compute the radar sensor confidence map which is used for sensor fusion.

  9. Biomechanical model-based displacement estimation in micro-sensor motion capture

    International Nuclear Information System (INIS)

    Meng, X L; Sun, S Y; Wu, J K; Zhang, Z Q; 3 Building, 21 Heng Mui Keng Terrace (Singapore))" data-affiliation=" (Department of Electrical and Computer Engineering, National University of Singapore (NUS), 02-02-10 I3 Building, 21 Heng Mui Keng Terrace (Singapore))" >Wong, W C

    2012-01-01

    In micro-sensor motion capture systems, the estimation of the body displacement in the global coordinate system remains a challenge due to lack of external references. This paper proposes a self-contained displacement estimation method based on a human biomechanical model to track the position of walking subjects in the global coordinate system without any additional supporting infrastructures. The proposed approach makes use of the biomechanics of the lower body segments and the assumption that during walking there is always at least one foot in contact with the ground. The ground contact joint is detected based on walking gait characteristics and used as the external references of the human body. The relative positions of the other joints are obtained from hierarchical transformations based on the biomechanical model. Anatomical constraints are proposed to apply to some specific joints of the lower body to further improve the accuracy of the algorithm. Performance of the proposed algorithm is compared with an optical motion capture system. The method is also demonstrated in outdoor and indoor long distance walking scenarios. The experimental results demonstrate clearly that the biomechanical model improves the displacement accuracy within the proposed framework. (paper)

  10. Sensitivity Enhancement of FBG-Based Strain Sensor.

    Science.gov (United States)

    Li, Ruiya; Chen, Yiyang; Tan, Yuegang; Zhou, Zude; Li, Tianliang; Mao, Jian

    2018-05-17

    A novel fiber Bragg grating (FBG)-based strain sensor with a high-sensitivity is presented in this paper. The proposed FBG-based strain sensor enhances sensitivity by pasting the FBG on a substrate with a lever structure. This typical mechanical configuration mechanically amplifies the strain of the FBG to enhance overall sensitivity. As this mechanical configuration has a high stiffness, the proposed sensor can achieve a high resonant frequency and a wide dynamic working range. The sensing principle is presented, and the corresponding theoretical model is derived and validated. Experimental results demonstrate that the developed FBG-based strain sensor achieves an enhanced strain sensitivity of 6.2 pm/με, which is consistent with the theoretical analysis result. The strain sensitivity of the developed sensor is 5.2 times of the strain sensitivity of a bare fiber Bragg grating strain sensor. The dynamic characteristics of this sensor are investigated through the finite element method (FEM) and experimental tests. The developed sensor exhibits an excellent strain-sensitivity-enhancing property in a wide frequency range. The proposed high-sensitivity FBG-based strain sensor can be used for small-amplitude micro-strain measurement in harsh industrial environments.

  11. Adaptation of Dubins Paths for UAV Ground Obstacle Avoidance When Using a Low Cost On-Board GNSS Sensor

    Directory of Open Access Journals (Sweden)

    Ramūnas Kikutis

    2017-09-01

    Full Text Available Current research on Unmanned Aerial Vehicles (UAVs shows a lot of interest in autonomous UAV navigation. This interest is mainly driven by the necessity to meet the rules and restrictions for small UAV flights that are issued by various international and national legal organizations. In order to lower these restrictions, new levels of automation and flight safety must be reached. In this paper, a new method for ground obstacle avoidance derived by using UAV navigation based on the Dubins paths algorithm is presented. The accuracy of the proposed method has been tested, and research results have been obtained by using Software-in-the-Loop (SITL simulation and real UAV flights, with the measurements done with a low cost Global Navigation Satellite System (GNSS sensor. All tests were carried out in a three-dimensional space, but the height accuracy was not assessed. The GNSS navigation data for the ground obstacle avoidance algorithm is evaluated statistically.

  12. Adaptation of Dubins Paths for UAV Ground Obstacle Avoidance When Using a Low Cost On-Board GNSS Sensor.

    Science.gov (United States)

    Kikutis, Ramūnas; Stankūnas, Jonas; Rudinskas, Darius; Masiulionis, Tadas

    2017-09-28

    Current research on Unmanned Aerial Vehicles (UAVs) shows a lot of interest in autonomous UAV navigation. This interest is mainly driven by the necessity to meet the rules and restrictions for small UAV flights that are issued by various international and national legal organizations. In order to lower these restrictions, new levels of automation and flight safety must be reached. In this paper, a new method for ground obstacle avoidance derived by using UAV navigation based on the Dubins paths algorithm is presented. The accuracy of the proposed method has been tested, and research results have been obtained by using Software-in-the-Loop (SITL) simulation and real UAV flights, with the measurements done with a low cost Global Navigation Satellite System (GNSS) sensor. All tests were carried out in a three-dimensional space, but the height accuracy was not assessed. The GNSS navigation data for the ground obstacle avoidance algorithm is evaluated statistically.

  13. GNSS as a sea ice sensor - detecting coastal freeze states with ground-based GNSS-R

    Science.gov (United States)

    Strandberg, Joakim; Hobiger, Thomas; Haas, Rüdiger

    2017-04-01

    Based on the idea of using freely available signals for remote sensing, ground-based GNSS-reflectometry (GNSS-R) has found more and more applications in hydrology, oceanography, agriculture and other Earth sciences. GNSS-R is based on analysing the elevation dependent SNR patterns of GNSS signals, and traditionally only the oscillation frequency and phase have been studied to retrieve parameters from the reflecting surfaces. However, recently Strandberg et al. (2016) developed an inversion algorithm that has changed the paradigms of ground-based GNSS-R as it enables direct access to the radiometric properties of the reflector. Using the signal envelope and the rate at which the magnitude of the SNR oscillations are damped w.r.t. satellite elevation, the algorithm retrieves the roughness of the reflector surface amongst other parameters. Based on this idea, we demonstrate for the first time that a GNSS installation situated close to the coastline can detect the presence of sea-ice unambiguously. Using data from the GTGU antenna at the Onsala Space Observatory, Sweden, the time series of the derived damping parameter clearly matches the occurrence of ice in the bay where the antenna is situated. Our results were validated against visual inspection logs as well as with the help of ice charts from the Swedish Meteorological and Hydrological Institute. Our method is even sensitive to partial and intermediate ice formation stages, with clear difference in response between frazil ice and both open and solidly frozen water surfaces. As the GTGU installation is entirely built with standard geodetic equipment, the method can be applied directly to any coastal GNSS site, allowing analysis of both new and historical data. One can use the method as an automatic way of retrieving independent ground truth data for ice extent measurements for use in hydrology, cryosphere studies, and even societal interest fields such as sea transportation. Finally, the new method opens up for

  14. The parameters of a sensor

    International Nuclear Information System (INIS)

    Neacsu, A.; Ciucu, C.

    2004-01-01

    The development of electronics and technology led to the development of high precision sensors. Generally all sensors are based on the inertia of a suspended mass which remains stationary with respect to the ground's movement. In the case of electromagnetic instruments, a coil is linked to the mass of a pendulum that moves in a magnetic field, creating an electric tension. In the case of this sensor, there is no need for a damper mechanism due to the fact that the damping force is produced by the currents induced in a copper plate oscillating in a strong magnetic field. In the experiment we determined the inner oscillating frequency and the damping factor of a sensor based on a mobile coil. (authors)

  15. Web of Things-Based Remote Monitoring System for Coal Mine Safety Using Wireless Sensor Network

    OpenAIRE

    Bo, Cheng; Xin, Cheng; Zhongyi, Zhai; Chengwen, Zhang; Junliang, Chen

    2014-01-01

    Frequent accidents have occurred in coal mine enterprises; therefore, raising the technological level of coal mine safety monitoring systems is an urgent problem. Wireless sensor networks (WSN), as a new field of research, have broad application prospects. This paper proposes a Web of Things- (WoT-) based remote monitoring system that takes full advantage of wireless sensor networks in combination with the CAN bus communication technique that abstracts the underground sensor data and capabili...

  16. Model-based Sensor Data Acquisition and Management

    OpenAIRE

    Aggarwal, Charu C.; Sathe, Saket; Papaioannou, Thanasis G.; Jeung, Ho Young; Aberer, Karl

    2012-01-01

    In recent years, due to the proliferation of sensor networks, there has been a genuine need of researching techniques for sensor data acquisition and management. To this end, a large number of techniques have emerged that advocate model-based sensor data acquisition and management. These techniques use mathematical models for performing various, day-to-day tasks involved in managing sensor data. In this chapter, we survey the state-of-the-art techniques for model-based sensor data acquisition...

  17. On-Board Mining in the Sensor Web

    Science.gov (United States)

    Tanner, S.; Conover, H.; Graves, S.; Ramachandran, R.; Rushing, J.

    2004-12-01

    On-board data mining can contribute to many research and engineering applications, including natural hazard detection and prediction, intelligent sensor control, and the generation of customized data products for direct distribution to users. The ability to mine sensor data in real time can also be a critical component of autonomous operations, supporting deep space missions, unmanned aerial and ground-based vehicles (UAVs, UGVs), and a wide range of sensor meshes, webs and grids. On-board processing is expected to play a significant role in the next generation of NASA, Homeland Security, Department of Defense and civilian programs, providing for greater flexibility and versatility in measurements of physical systems. In addition, the use of UAV and UGV systems is increasing in military, emergency response and industrial applications. As research into the autonomy of these vehicles progresses, especially in fleet or web configurations, the applicability of on-board data mining is expected to increase significantly. Data mining in real time on board sensor platforms presents unique challenges. Most notably, the data to be mined is a continuous stream, rather than a fixed store such as a database. This means that the data mining algorithms must be modified to make only a single pass through the data. In addition, the on-board environment requires real time processing with limited computing resources, thus the algorithms must use fixed and relatively small amounts of processing time and memory. The University of Alabama in Huntsville is developing an innovative processing framework for the on-board data and information environment. The Environment for On-Board Processing (EVE) and the Adaptive On-board Data Processing (AODP) projects serve as proofs-of-concept of advanced information systems for remote sensing platforms. The EVE real-time processing infrastructure will upload, schedule and control the execution of processing plans on board remote sensors. These plans

  18. Resource Discovery in Activity-Based Sensor Networks

    DEFF Research Database (Denmark)

    Bucur, Doina; Bardram, Jakob

    This paper proposes a service discovery protocol for sensor networks that is specifically tailored for use in humancentered pervasive environments. It uses the high-level concept of computational activities (as logical bundles of data and resources) to give sensors in Activity-Based Sensor Networ....... ABSN enhances the generic Extended Zone Routing Protocol with logical sensor grouping and greatly lowers network overhead during the process of discovery, while keeping discovery latency close to optimal.......This paper proposes a service discovery protocol for sensor networks that is specifically tailored for use in humancentered pervasive environments. It uses the high-level concept of computational activities (as logical bundles of data and resources) to give sensors in Activity-Based Sensor Networks...... (ABSNs) knowledge about their usage even at the network layer. ABSN redesigns classical network-level service discovery protocols to include and use this logical structuring of the network for a more practically applicable service discovery scheme. Noting that in practical settings activity-based sensor...

  19. A New User Interface for On-Demand Customizable Data Products for Sensors in a SensorWeb

    Science.gov (United States)

    Mandl, Daniel; Cappelaere, Pat; Frye, Stuart; Sohlberg, Rob; Ly, Vuong; Chien, Steve; Sullivan, Don

    2011-01-01

    A SensorWeb is a set of sensors, which can consist of ground, airborne and space-based sensors interoperating in an automated or autonomous collaborative manner. The NASA SensorWeb toolbox, developed at NASA/GSFC in collaboration with NASA/JPL, NASA/Ames and other partners, is a set of software and standards that (1) enables users to create virtual private networks of sensors over open networks; (2) provides the capability to orchestrate their actions; (3) provides the capability to customize the output data products and (4) enables automated delivery of the data products to the users desktop. A recent addition to the SensorWeb Toolbox is a new user interface, together with web services co-resident with the sensors, to enable rapid creation, loading and execution of new algorithms for processing sensor data. The web service along with the user interface follows the Open Geospatial Consortium (OGC) standard called Web Coverage Processing Service (WCPS). This presentation will detail the prototype that was built and how the WCPS was tested against a HyspIRI flight testbed and an elastic computation cloud on the ground with EO-1 data. HyspIRI is a future NASA decadal mission. The elastic computation cloud stores EO-1 data and runs software similar to Amazon online shopping.

  20. Bridge Testing With Ground-Based Interferometric Radar: Experimental Results

    International Nuclear Information System (INIS)

    Chiara, P.; Morelli, A.

    2010-01-01

    The research of innovative non-contact techniques aimed at the vibration measurement of civil engineering structures (also for damage detection and structural health monitoring) is continuously directed to the optimization of measures and methods. Ground-Based Radar Interferometry (GBRI) represents the more recent technique available for static and dynamic control of structures and ground movements.Dynamic testing of bridges and buildings in operational conditions are currently performed: (a) to assess the conformity of the structure to the project design at the end of construction; (b) to identify the modal parameters (i.e. natural frequencies, mode shapes and damping ratios) and to check the variation of any modal parameters over the years; (c) to evaluate the amplitude of the structural response to special load conditions (i.e. strong winds, earthquakes, heavy railway or roadway loads). If such tests are carried out by using a non-contact technique (like GBRI), the classical issues of contact sensors (like accelerometers) are easily overtaken.This paper presents and discusses the results of various tests carried out on full-scale bridges by using a Stepped Frequency-Continuous Wave radar system.

  1. Bridge Testing With Ground-Based Interferometric Radar: Experimental Results

    Science.gov (United States)

    Chiara, P.; Morelli, A.

    2010-05-01

    The research of innovative non-contact techniques aimed at the vibration measurement of civil engineering structures (also for damage detection and structural health monitoring) is continuously directed to the optimization of measures and methods. Ground-Based Radar Interferometry (GBRI) represents the more recent technique available for static and dynamic control of structures and ground movements. Dynamic testing of bridges and buildings in operational conditions are currently performed: (a) to assess the conformity of the structure to the project design at the end of construction; (b) to identify the modal parameters (i.e. natural frequencies, mode shapes and damping ratios) and to check the variation of any modal parameters over the years; (c) to evaluate the amplitude of the structural response to special load conditions (i.e. strong winds, earthquakes, heavy railway or roadway loads). If such tests are carried out by using a non-contact technique (like GBRI), the classical issues of contact sensors (like accelerometers) are easily overtaken. This paper presents and discusses the results of various tests carried out on full-scale bridges by using a Stepped Frequency-Continuous Wave radar system.

  2. Simultaneous Retrieval of Aerosol and Surface Optical Properties from Combined Airborne- and Ground-Based Direct and Diffuse Radiometric Measurements

    Science.gov (United States)

    Gatebe, C. K.; Dubovik, O.; King, M. D.; Sinyuk, A.

    2010-01-01

    This paper presents a new method for simultaneously retrieving aerosol and surface reflectance properties from combined airborne and ground-based direct and diffuse radiometric measurements. The method is based on the standard Aerosol Robotic Network (AERONET) method for retrieving aerosol size distribution, complex index of refraction, and single scattering albedo, but modified to retrieve aerosol properties in two layers, below and above the aircraft, and parameters on surface optical properties from combined datasets (Cloud Absorption Radiometer (CAR) and AERONET data). A key advantage of this method is the inversion of all available spectral and angular data at the same time, while accounting for the influence of noise in the inversion procedure using statistical optimization. The wide spectral (0.34-2.30 m) and angular range (180 ) of the CAR instrument, combined with observations from an AERONET sunphotometer, provide sufficient measurement constraints for characterizing aerosol and surface properties with minimal assumptions. The robustness of the method was tested on observations made during four different field campaigns: (a) the Southern African Regional Science Initiative 2000 over Mongu, Zambia, (b) the Intercontinental Transport Experiment-Phase B over Mexico City, Mexico (c) Cloud and Land Surface Interaction Campaign over the Atmospheric Radiation Measurement (ARM) Central Facility, Oklahoma, USA, and (d) the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) over Elson Lagoon in Barrow, Alaska, USA. The four areas are dominated by different surface characteristics and aerosol types, and therefore provide good test cases for the new inversion method.

  3. STUDY ON ALGORITHM OF SENSOR MANAGEMENT BASED ON FUNCTIONS OF EFFICIENCY AND WASTE

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Sensor management plays an important role in data fusion system, and this paper presents an algorithm of sensor management that can be used in target detection, identification and tracking. First, the basic concept, rule, range and function of sensor management are introduced. Then, the quantifying problems of target priority and sensor (or combination)-target pairing in multisensor management are discussed and the efficiency and waste functions are established based on the functions of target priority and sensor-target pairing. On this basis, a distribution algorithm of multisensor resources is given, which is optimized by the principle of maximum synthesis efficiency in the multisensor system and constrained by sensor maximum tracking power and what target must be scanned. In addition, the waste measure of sensor resources is introduced to improve the algorithm. Finally, a tactical task that includes three sensors and ten targets is set, and the simulation results show that the algorithm is feasible and effective.

  4. Remote sensing of high-latitude ionization profiles by ground-based and spaceborne instrumentation

    International Nuclear Information System (INIS)

    Vondrak, R.R.

    1981-01-01

    Ionospheric specification and modeling are now largely based on data provided by active remote sensing with radiowave techniques (ionosondes, incoherent-scatter radars, and satellite beacons). More recently, passive remote sensing techniques have been developed that can be used to monitor quantitatively the spatial distribution of high-latitude E-region ionization. These passive methods depend on the measurement, or inference, of the energy distribution of precipitating kilovolt electrons, the principal source of the nighttime E-region at high latitudes. To validate these techniques, coordinated measurements of the auroral ionosphere have been made with the Chatanika incoherent-scatter radar and a variety of ground-based and spaceborne sensors

  5. VLC-based indoor location awareness using LED light and image sensors

    Science.gov (United States)

    Lee, Seok-Ju; Yoo, Jong-Ho; Jung, Sung-Yoon

    2012-11-01

    Recently, indoor LED lighting can be considered for constructing green infra with energy saving and additionally providing LED-IT convergence services such as visible light communication (VLC) based location awareness and navigation services. For example, in case of large complex shopping mall, location awareness to navigate the destination is very important issue. However, the conventional navigation using GPS is not working indoors. Alternative location service based on WLAN has a problem that the position accuracy is low. For example, it is difficult to estimate the height exactly. If the position error of the height is greater than the height between floors, it may cause big problem. Therefore, conventional navigation is inappropriate for indoor navigation. Alternative possible solution for indoor navigation is VLC based location awareness scheme. Because indoor LED infra will be definitely equipped for providing lighting functionality, indoor LED lighting has a possibility to provide relatively high accuracy of position estimation combined with VLC technology. In this paper, we provide a new VLC based positioning system using visible LED lights and image sensors. Our system uses location of image sensor lens and location of reception plane. By using more than two image sensor, we can determine transmitter position less than 1m position error. Through simulation, we verify the validity of the proposed VLC based new positioning system using visible LED light and image sensors.

  6. Relational-Based Sensor Data Cleansing

    DEFF Research Database (Denmark)

    Iftikhar, Nadeem; Nordbjerg, Finn Ebertsen

    2015-01-01

    approaches, such as classification, prediction and moving average, are not suited for embedded sensor devices, due to their limit storage and processing capabilities. In this paper, we propose a sensor data cleansing approach using the relational-based technologies, including constraints, triggers...... and granularity-based data aggregation. The proposed approach is simple but effective to cleanse different types of dirty data, including delayed data, incomplete data, incorrect data, duplicate data and missing data. We evaluate the proposed strategy to verify its efficiency and effectiveness.......Today sensors are widely used in many monitoring applications. Due to some random environmental effects and/or sensing failures, the collected sensor data is typically noisy. Thus, it is critical to cleanse the data before using it for answering queries or for data analysis. Popular data cleansing...

  7. Assessment of a combined gas chromatography mass spectrometer sensor (GC-MSS) system for detecting biologically relevant volatile compounds (VCs).

    Science.gov (United States)

    Gould, Oliver; Wieczorek, Tomas; de Lacy Costello, Ben P J; Persad, Raj; Ratcliffe, Norman

    2017-09-26

    There have been a number of studies in which metal oxide sensors (MOS) have replaced conventional analytical detectors in gas chromatography systems. However, despite the use of these instruments in a range of applications including breath research the sensor responses (i.e. resistance changes w.r.t. concentration of VCs) remain largely unreported. This paper addresses that issue by comparing the response of a metal oxide sensor directly with a mass spectrometer (MS), whereby both detectors are interfaced to the same GC column using an s-swafer. It was demonstrated that the sensitivity of an in-house fabricated ZnO/ SnO2 thick film MOS was superior to a modern MS for the detection of a wide range of volatile compounds (VCs) of different functionalities and masses. Better techniques for detection and quantification of these VCs is valuable, as many of these compounds are commonly reported throughout the scientific literature. This is also the first published report of a combined GC-MS sensor system. These 2 different detector technologies when combined, should enhance discriminatory abilities to aid disease diagnoses using volatiles from e.g. breath, and bodily fluids. 29 chemical standards have been tested using solid phase micro-extraction; 25 of these compounds are found on human breath. In all but 2 instances the sensor exhibited the same or superior limit of detection compared to the MS. 12 stool samples from healthy participants were analysed, the sensor detected, on average 1.6 peaks more per sample than the MS. Similarly analysing the headspace of E. coli broth cultures the sensor detected 6.9 more peaks per sample versus the MS. This greater sensitivity is primarily a function of the superior limits of detection of the metal oxide sensor. This shows that systems based on the combination of chromatography systems with solid state sensors shows promise for a range of applications. © 2017 IOP Publishing Ltd.

  8. Carbon Nanotube Based Chemical Sensors for Space and Terrestrial Applications

    Science.gov (United States)

    Li, Jing; Lu, Yijiang

    2009-01-01

    A nanosensor technology has been developed using nanostructures, such as single walled carbon nanotubes (SWNTs), on a pair of interdigitated electrodes (IDE) processed with a silicon-based microfabrication and micromachining technique. The IDE fingers were fabricated using photolithography and thin film metallization techniques. Both in-situ growth of nanostructure materials and casting of the nanostructure dispersions were used to make chemical sensing devices. These sensors have been exposed to nitrogen dioxide, acetone, benzene, nitrotoluene, chlorine, and ammonia in the concentration range of ppm to ppb at room temperature. The electronic molecular sensing of carbon nanotubes in our sensor platform can be understood by intra- and inter-tube electron modulation in terms of charge transfer mechanisms. As a result of the charge transfer, the conductance of p-type or hole-richer SWNTs in air will change. Due to the large surface area, low surface energy barrier and high thermal and mechanical stability, nanostructured chemical sensors potentially can offer higher sensitivity, lower power consumption and better robustness than the state-of-the-art systems, which make them more attractive for defense and space applications. Combined with MEMS technology, light weight and compact size sensors can be made in wafer scale with low cost. Additionally, a wireless capability of such a sensor chip can be used for networked mobile and fixed-site detection and warning systems for military bases, facilities and battlefield areas.

  9. Surface plasmon resonance based optical fiber riboflavin sensor by using molecularly imprinted gel

    Science.gov (United States)

    Verma, Roli; Gupta, Banshi D.

    2013-05-01

    We report the fabrication and characterization of surface plasmon resonance (SPR) based optical fiber riboflavin/vitamin B2 sensor using combination of colloidal crystal templating and molecularly imprinted gel. The sensor works on spectral interrogation method. The operating range of the sensor lies from 0 μg/ml to 320 μg/ml, the suitable amount of intakes of riboflavin recommended for different age group. The SPR spectra show blue shift with increasing concentration of riboflavin, which is due to the interaction of riboflavin molecule over specific binding sites caused by molecular imprinting. The present sensor has many advantageous features such as fast response, small probe size, low cost and can be used for remote/online monitoring.

  10. Unmanned Aerial System (UAS)-based phenotyping of soybean using multi-sensor data fusion and extreme learning machine

    Science.gov (United States)

    Maimaitijiang, Maitiniyazi; Ghulam, Abduwasit; Sidike, Paheding; Hartling, Sean; Maimaitiyiming, Matthew; Peterson, Kyle; Shavers, Ethan; Fishman, Jack; Peterson, Jim; Kadam, Suhas; Burken, Joel; Fritschi, Felix

    2017-12-01

    Estimating crop biophysical and biochemical parameters with high accuracy at low-cost is imperative for high-throughput phenotyping in precision agriculture. Although fusion of data from multiple sensors is a common application in remote sensing, less is known on the contribution of low-cost RGB, multispectral and thermal sensors to rapid crop phenotyping. This is due to the fact that (1) simultaneous collection of multi-sensor data using satellites are rare and (2) multi-sensor data collected during a single flight have not been accessible until recent developments in Unmanned Aerial Systems (UASs) and UAS-friendly sensors that allow efficient information fusion. The objective of this study was to evaluate the power of high spatial resolution RGB, multispectral and thermal data fusion to estimate soybean (Glycine max) biochemical parameters including chlorophyll content and nitrogen concentration, and biophysical parameters including Leaf Area Index (LAI), above ground fresh and dry biomass. Multiple low-cost sensors integrated on UASs were used to collect RGB, multispectral, and thermal images throughout the growing season at a site established near Columbia, Missouri, USA. From these images, vegetation indices were extracted, a Crop Surface Model (CSM) was advanced, and a model to extract the vegetation fraction was developed. Then, spectral indices/features were combined to model and predict crop biophysical and biochemical parameters using Partial Least Squares Regression (PLSR), Support Vector Regression (SVR), and Extreme Learning Machine based Regression (ELR) techniques. Results showed that: (1) For biochemical variable estimation, multispectral and thermal data fusion provided the best estimate for nitrogen concentration and chlorophyll (Chl) a content (RMSE of 9.9% and 17.1%, respectively) and RGB color information based indices and multispectral data fusion exhibited the largest RMSE 22.6%; the highest accuracy for Chl a + b content estimation was

  11. A feasible system integrating combined heating and power system with ground-source heat pump

    International Nuclear Information System (INIS)

    Li, HongQiang; Kang, ShuShuo; Yu, Zhun; Cai, Bo; Zhang, GuoQiang

    2014-01-01

    A system integrating CHP (combined heating and power) subsystem based on natural gas and GSHP (ground-source heat pump subsystem) in series is proposed. By help of simulation software-Aspen Plus, the energy performance of a typical CHP and GSHP-S (S refers to ‘in series’) system was analyzed. The results show that the system can make a better use of waste heat in flue gas from CHP (combined heating and power subsystem). The total system energy efficiency is 123% and the COP (coefficient of performance) of GSHP (ground-source heat pump) subsystem is 5.3. A referenced CHP and GSHP-P (P refers to ‘in parallel’) system is used for comparison; its total system energy efficiency and COP of GSHP subsystem are 118.6% and 3.5 respectively. Compared with CHP and GSHP-P system with different operating parameters, the CHP and GSHP-S system can increase total system energy efficiency by 0.8–34.7%, with related output ratio of heat to power (R) from 1.9 to 18.3. Furthermore, the COP of GSHP subsystem can be increased between the range 3.6 and 6, which is much higher than that in conventional CHP and GSHP-P system. This study will be helpful for other efficient GSHP systems integrating if there is waste heat or other heat resources with low temperature. - Highlights: • CHP system based on natural gas and ground source heat pump. • The new system can make a better utilization of waste heat in flue gas by a special way. • The proposed system can realize energy saving potential from 0.8 to 34.7%. • The coefficient of performance of ground source heat pump subsystem is significantly improved from 3.5 to 3.6–6. • Warm water temperature and percentage of flue gas used to reheat are key parameters

  12. Ground-based SMART-COMMIT Measurements for Studying Aerosol and Cloud Properties

    Science.gov (United States)

    Tsay, Si-Chee

    2008-01-01

    From radiometric principles, it is expected that the retrieved properties of extensive aerosols and clouds from reflected/emitted measurements by satellite (and/or aircraft) should be consistent with those retrieved from transmitted/emitted radiance observed at the surface. Although space-borne remote sensing observations cover large spatial domain, they are often plagued by contamination of surface signatures. Thus, ground-based in-situ and remote-sensing measurements, where signals come directly from atmospheric constituents, the sun, and/or the Earth-atmosphere interactions, provide additional information content for comparisons that confirm quantitatively the usefulness of the integrated surface, aircraft, and satellite data sets. The development and deployment of SMARTCOMMIT (Surface-sensing Measurements for Atmospheric Radiative Transfer - Chemical, Optical & Microphysical Measurements of In-situ Troposphere) mobile facilities are aimed for the optimal utilization of collocated ground-based observations as constraints to yield higher fidelity satellite retrievals and to determine any sampling bias due to target conditions. To quantify the energetics of the surface-atmosphere system and the atmospheric processes, SMART-COMMIT instruments fall into three categories: flux radiometer, radiance sensor and in-situ probe. In this paper, we will demonstrate the capability of SMART-COMMIT in recent field campaigns (e.g., CRYSTAL-FACE, UAE 2, BASEASIA, NAMMA) that were designed and executed to study the compelling variability in temporal scale of both anthropogenic and natural aerosols (e.g., biomass-burning smoke, airborne dust) and cirrus clouds. We envision robust approaches in which well-collocated ground-based measurements and space-borne observations will greatly advance our knowledge of extensive aerosols and clouds.

  13. Multi-Sensor Mud Detection

    Science.gov (United States)

    Rankin, Arturo L.; Matthies, Larry H.

    2010-01-01

    Robust mud detection is a critical perception requirement for Unmanned Ground Vehicle (UGV) autonomous offroad navigation. A military UGV stuck in a mud body during a mission may have to be sacrificed or rescued, both of which are unattractive options. There are several characteristics of mud that may be detectable with appropriate UGV-mounted sensors. For example, mud only occurs on the ground surface, is cooler than surrounding dry soil during the daytime under nominal weather conditions, is generally darker than surrounding dry soil in visible imagery, and is highly polarized. However, none of these cues are definitive on their own. Dry soil also occurs on the ground surface, shadows, snow, ice, and water can also be cooler than surrounding dry soil, shadows are also darker than surrounding dry soil in visible imagery, and cars, water, and some vegetation are also highly polarized. Shadows, snow, ice, water, cars, and vegetation can all be disambiguated from mud by using a suite of sensors that span multiple bands in the electromagnetic spectrum. Because there are military operations when it is imperative for UGV's to operate without emitting strong, detectable electromagnetic signals, passive sensors are desirable. JPL has developed a daytime mud detection capability using multiple passive imaging sensors. Cues for mud from multiple passive imaging sensors are fused into a single mud detection image using a rule base, and the resultant mud detection is localized in a terrain map using range data generated from a stereo pair of color cameras.

  14. A multifunctional PVDF-based tactile sensor for minimally invasive surgery

    Science.gov (United States)

    Sokhanvar, S.; Packirisamy, M.; Dargahi, J.

    2007-08-01

    In this paper a multifunctional tactile sensor system using PVDF (polyvinylidene fluoride), is proposed, designed, analyzed, tested and validated. The working principle of the sensor is in such a way that it can be used in combination with almost any end-effectors. However, the sensor is particularly designed to be integrated with minimally invasive surgery (MIS) tools. In addition, the structural and transduction materials are selected to be compatible with micro-electro-mechanical systems (MEMS) technology, so that miniaturization would be possible. The corrugated shape of the sensor ensures the safe tissue grasping and compatibility with the traditional tooth-like end effectors of MIS tools. A unit of this sensor comprised of a base, a flexible beam and three PVDF sensing elements. Two PVDF sensing elements sandwiched at the end supports work in thickness mode to measure the magnitude and position of applied load. The third PVDF sensing element is attached to the beam and it works in the extensional mode to measure the softness of the contact object. The proposed sensor is modeled both analytically and numerically and a series of simulations are performed in order to estimate the characteristics of the sensor in measuring the magnitude and position of a point load, distributed load, and also the softness of the contact object. Furthermore, in order to validate the theoretical results, the prototyped sensor was tested and the results are compared. The results are very promising and proving the capability of the sensor for haptic sensing.

  15. Development of Smart Sensors System Based on Formal Concept Analysis and Ontology Model

    Directory of Open Access Journals (Sweden)

    Hongsheng Xu

    2013-06-01

    Full Text Available The smart sensor is the product of the combination of one or more sensitive components, precision analog circuits, digital circuits, microprocessor, communication interface, intelligent software systems and hardware integration in a packaging component. Formal concept analysis is from the given data to automatically extract the classification relationship between the entire hidden concept and concept, formation of concept model. Ontology is a set of relations between concepts of the specific domain and concept, and it can effectively express the general knowledge of specific field. The paper proposes development of smart sensors system based on formal concept analysis and ontology model. Smart sensor is a micro processor, sensor with information detection, information processing, information memory, logical thinking and judging function. The methods can improve the effect of the smart sensors.

  16. Conflict management based on belief function entropy in sensor fusion.

    Science.gov (United States)

    Yuan, Kaijuan; Xiao, Fuyuan; Fei, Liguo; Kang, Bingyi; Deng, Yong

    2016-01-01

    Wireless sensor network plays an important role in intelligent navigation. It incorporates a group of sensors to overcome the limitation of single detection system. Dempster-Shafer evidence theory can combine the sensor data of the wireless sensor network by data fusion, which contributes to the improvement of accuracy and reliability of the detection system. However, due to different sources of sensors, there may be conflict among the sensor data under uncertain environment. Thus, this paper proposes a new method combining Deng entropy and evidence distance to address the issue. First, Deng entropy is adopted to measure the uncertain information. Then, evidence distance is applied to measure the conflict degree. The new method can cope with conflict effectually and improve the accuracy and reliability of the detection system. An example is illustrated to show the efficiency of the new method and the result is compared with that of the existing methods.

  17. A ground temperature map of the North Atlantic permafrost region based on remote sensing and reanalysis data

    DEFF Research Database (Denmark)

    Westermann, S.; Østby, T. I.; Gisnås, K.

    2015-01-01

    Permafrost is a key element of the terrestrial cryosphere which makes mapping and monitoring of its state variables an imperative task. We present a modeling scheme based on remotely sensed land surface temperatures and reanalysis products from which mean annual ground temperatures (MAGT) can be ...... with gradually decreasing permafrost probabilities. The study exemplifies the unexploited potential of remotely sensed data sets in permafrost mapping if they are employed in multi-sensor multi-source data fusion approaches.......Permafrost is a key element of the terrestrial cryosphere which makes mapping and monitoring of its state variables an imperative task. We present a modeling scheme based on remotely sensed land surface temperatures and reanalysis products from which mean annual ground temperatures (MAGT) can...

  18. A Review on Surface Stress-Based Miniaturized Piezoresistive SU-8 Polymeric Cantilever Sensors

    Science.gov (United States)

    Mathew, Ribu; Ravi Sankar, A.

    2018-06-01

    In the last decade, microelectromechanical systems (MEMS) SU-8 polymeric cantilevers with piezoresistive readout combined with the advances in molecular recognition techniques have found versatile applications, especially in the field of chemical and biological sensing. Compared to conventional solid-state semiconductor-based piezoresistive cantilever sensors, SU-8 polymeric cantilevers have advantages in terms of better sensitivity along with reduced material and fabrication cost. In recent times, numerous researchers have investigated their potential as a sensing platform due to high performance-to-cost ratio of SU-8 polymer-based cantilever sensors. In this article, we critically review the design, fabrication, and performance aspects of surface stress-based piezoresistive SU-8 polymeric cantilever sensors. The evolution of surface stress-based piezoresistive cantilever sensors from solid-state semiconductor materials to polymers, especially SU-8 polymer, is discussed in detail. Theoretical principles of surface stress generation and their application in cantilever sensing technology are also devised. Variants of SU-8 polymeric cantilevers with different composition of materials in cantilever stacks are explained. Furthermore, the interdependence of the material selection, geometrical design parameters, and fabrication process of piezoresistive SU-8 polymeric cantilever sensors and their cumulative impact on the sensor response are also explained in detail. In addition to the design-, fabrication-, and performance-related factors, this article also describes various challenges in engineering SU-8 polymeric cantilevers as a universal sensing platform such as temperature and moisture vulnerability. This review article would serve as a guideline for researchers to understand specifics and functionality of surface stress-based piezoresistive SU-8 cantilever sensors.[Figure not available: see fulltext.

  19. ENERGY OPTIMIZATION IN CLUSTER BASED WIRELESS SENSOR NETWORKS

    Directory of Open Access Journals (Sweden)

    T. SHANKAR

    2014-04-01

    Full Text Available Wireless sensor networks (WSN are made up of sensor nodes which are usually battery-operated devices, and hence energy saving of sensor nodes is a major design issue. To prolong the networks lifetime, minimization of energy consumption should be implemented at all layers of the network protocol stack starting from the physical to the application layer including cross-layer optimization. Optimizing energy consumption is the main concern for designing and planning the operation of the WSN. Clustering technique is one of the methods utilized to extend lifetime of the network by applying data aggregation and balancing energy consumption among sensor nodes of the network. This paper proposed new version of Low Energy Adaptive Clustering Hierarchy (LEACH, protocols called Advanced Optimized Low Energy Adaptive Clustering Hierarchy (AOLEACH, Optimal Deterministic Low Energy Adaptive Clustering Hierarchy (ODLEACH, and Varying Probability Distance Low Energy Adaptive Clustering Hierarchy (VPDL combination with Shuffled Frog Leap Algorithm (SFLA that enables selecting best optimal adaptive cluster heads using improved threshold energy distribution compared to LEACH protocol and rotating cluster head position for uniform energy dissipation based on energy levels. The proposed algorithm optimizing the life time of the network by increasing the first node death (FND time and number of alive nodes, thereby increasing the life time of the network.

  20. How ground-based observations can support satellite greenhouse gas retrievals

    Science.gov (United States)

    Butler, J. H.; Tans, P. P.; Sweeney, C.; Dlugokencky, E. J.

    2012-04-01

    Global society will eventually accelerate efforts to reduce greenhouse gas emissions in a variety of ways. These would likely involve international treaties, national policies, and regional strategies that will affect a number of economic, social, and environmental sectors. Some strategies will work better than others and some will not work at all. Because trillions of dollars will be involved in pursuing greenhouse gas emission reductions - through realignment of energy production, improvement of efficiencies, institution of taxes, implementation of carbon trading markets, and use of offsets - it is imperative that society be given all the tools at its disposal to ensure the ultimate success of these efforts. Providing independent, globally coherent information on the success of these efforts will give considerable strength to treaties, policies, and strategies. Doing this will require greenhouse gas observations greatly expanded from what we have today. Satellite measurements may ultimately be indispensable in achieving global coverage, but the requirements for accuracy and continuity of measurements over time are demanding if the data are to be relevant. Issues such as those associated with sensor drift, aging electronics, and retrieval artifacts present challenges that can be addressed in part by close coordination with ground-based and in situ systems. This presentation identifies the information that ground-based systems provide very well, but it also looks at what would be deficient even in a greatly expanded surface system, where satellites can fill these gaps, and how on-going, ground and in situ measurements can aid in addressing issues associated with accuracy, long-term continuity, and retrieval artifacts.

  1. Copper-based electrochemical sensor with palladium electrode for cathodic stripping voltammetry of manganese.

    Science.gov (United States)

    Kang, Wenjing; Pei, Xing; Bange, Adam; Haynes, Erin N; Heineman, William R; Papautsky, Ian

    2014-12-16

    In this work, we report on the development of a palladium-based, microfabricated point-of-care electrochemical sensor for the determination of manganese using square wave cathodic stripping voltammetry. Heavy metals require careful monitoring, yet current methods are too complex for a point-of-care system. Voltammetry offers an attractive approach to metal detection on the microscale, but traditional carbon, gold, or platinum electrodes are difficult or expensive to microfabricate, preventing widespread use. Our sensor uses palladium working and auxiliary electrodes and integrates them with a copper-based reference electrode for simple fabrication and compatibility with microfabrication and printed circuit board processing, while maintaining competitive performance in electrochemical detection. Copper electrodes were prepared on glass substrate using a combination of microfabrication procedures followed by electrodeposition of palladium. The disposable sensor system was formed by bonding a poly(dimethylsiloxane) (PDMS) well to the glass substrate. Cathodic stripping voltammetry of manganese using our new disposable palladium-based sensors exhibited 334 nM (18.3 ppb) limit of detection in borate buffer. The sensor was used to demonstrate manganese determination in natural water samples from a pond in Burnet Woods, located in Cincinnati, OH, and the Ohio River.

  2. Monolithic integration of micromachined sensors and CMOS circuits based on SOI technologies

    International Nuclear Information System (INIS)

    Yu Xiaomei; Tang Yaquan; Zhang Haitao

    2008-01-01

    This note presents a novel way to monolithically integrate micro-cantilever sensors and signal conditioning circuits by combining SOI CMOS and SOI micromachining technologies. In order to improve the sensor performance and reduce the system volume, an integrated sensor system composed of a piezoresistive cantilever array, a temperature-compensation current reference, a digitally controlled multiplexer and an instrument amplifier is designed and finally fabricated. A post-SOI CMOS process is developed to realize the integrated sensor system which is based on a standard CMOS process with one more mask to define the cantilever structure at the end of the process. Measurements on the finished SOI CMOS devices and circuits show that the integration process has good compatibility both for the cantilever sensors and for the CMOS circuits, and the SOI CMOS integration process can decrease about 25% sequences compared with the bulk silicon CMOS process. (note)

  3. Bioinspired optical sensors for unmanned aerial systems

    Science.gov (United States)

    Chahl, Javaan; Rosser, Kent; Mizutani, Akiko

    2011-04-01

    Insects are dependant on the spatial, spectral and temporal distributions of light in the environment for flight control and navigation. This paper reports on flight trials of implementations of insect inspired behaviors on unmanned aerial vehicles. Optical flow methods for maintaining a constant height above ground and a constant course have been demonstrated to provide navigation capabilities that are impossible using conventional avionics sensors. Precision control of height above ground and ground course were achieved over long distances. Other vision based techniques demonstrated include a biomimetic stabilization sensor that uses the ultraviolet and green bands of the spectrum, and a sky polarization compass. Both of these sensors were tested over long trajectories in different directions, in each case showing performance similar to low cost inertial heading and attitude systems. The behaviors demonstrate some of the core functionality found in the lower levels of the sensorimotor system of flying insects and shows promise for more integrated solutions in the future.

  4. A risk-based sensor placement methodology

    International Nuclear Information System (INIS)

    Lee, Ronald W.; Kulesz, James J.

    2008-01-01

    A risk-based sensor placement methodology is proposed to solve the problem of optimal location of sensors to protect population against the exposure to, and effects of, known and/or postulated chemical, biological, and/or radiological threats. Risk is calculated as a quantitative value representing population at risk from exposure at standard exposure levels. Historical meteorological data are used to characterize weather conditions as the frequency of wind speed and direction pairs. The meteorological data drive atmospheric transport and dispersion modeling of the threats, the results of which are used to calculate risk values. Sensor locations are determined via an iterative dynamic programming algorithm whereby threats detected by sensors placed in prior iterations are removed from consideration in subsequent iterations. In addition to the risk-based placement algorithm, the proposed methodology provides a quantification of the marginal utility of each additional sensor. This is the fraction of the total risk accounted for by placement of the sensor. Thus, the criteria for halting the iterative process can be the number of sensors available, a threshold marginal utility value, and/or a minimum cumulative utility achieved with all sensors

  5. A Multiobjective Fuzzy Inference System based Deployment Strategy for a Distributed Mobile Sensor Network

    Directory of Open Access Journals (Sweden)

    Amol P. Bhondekar

    2010-03-01

    Full Text Available Sensor deployment scheme highly governs the effectiveness of distributed wireless sensor network. Issues such as energy conservation and clustering make the deployment problem much more complex. A multiobjective Fuzzy Inference System based strategy for mobile sensor deployment is presented in this paper. This strategy gives a synergistic combination of energy capacity, clustering and peer-to-peer deployment. Performance of our strategy is evaluated in terms of coverage, uniformity, speed and clustering. Our algorithm is compared against a modified distributed self-spreading algorithm to exhibit better performance.

  6. Integrated Active Fire Retrievals and Biomass Burning Emissions Using Complementary Near-Coincident Ground, Airborne and Spaceborne Sensor Data

    Science.gov (United States)

    Schroeder, Wilfrid; Ellicott, Evan; Ichoku, Charles; Ellison, Luke; Dickinson, Matthew B.; Ottmar, Roger D.; Clements, Craig; Hall, Dianne; Ambrosia, Vincent; Kremens, Robert

    2013-01-01

    Ground, airborne and spaceborne data were collected for a 450 ha prescribed fire implemented on 18 October 2011 at the Henry W. Coe State Park in California. The integration of various data elements allowed near coincident active fire retrievals to be estimated. The Autonomous Modular Sensor-Wildfire (AMS) airborne multispectral imaging system was used as a bridge between ground and spaceborne data sets providing high quality reference information to support satellite fire retrieval error analyses and fire emissions estimates. We found excellent agreement between peak fire radiant heat flux data (less than 1% error) derived from near-coincident ground radiometers and AMS. Both MODIS and GOES imager active fire products were negatively influenced by the presence of thick smoke, which was misclassified as cloud by their algorithms, leading to the omission of fire pixels beneath the smoke, and resulting in the underestimation of their retrieved fire radiative power (FRP) values for the burn plot, compared to the reference airborne data. Agreement between airborne and spaceborne FRP data improved significantly after correction for omission errors and atmospheric attenuation, resulting in as low as 5 difference between AquaMODIS and AMS. Use of in situ fuel and fire energy estimates in combination with a collection of AMS, MODIS, and GOES FRP retrievals provided a fuel consumption factor of 0.261 kg per MJ, total energy release of 14.5 x 10(exp 6) MJ, and total fuel consumption of 3.8 x 10(exp 6) kg. Fire emissions were calculated using two separate techniques, resulting in as low as 15 difference for various species

  7. Highly Sensitive Liquid Core Temperature Sensor Based on Multimode Interference Effects

    Directory of Open Access Journals (Sweden)

    Miguel A. Fuentes-Fuentes

    2015-10-01

    Full Text Available A novel fiber optic temperature sensor based on a liquid-core multimode interference device is demonstrated. The advantage of such structure is that the thermo-optic coefficient (TOC of the liquid is at least one order of magnitude larger than that of silica and this, combined with the fact that the TOC of silica and the liquid have opposite signs, provides a liquid-core multimode fiber (MMF highly sensitive to temperature. Since the refractive index of the liquid can be easily modified, this allows us to control the modal properties of the liquid-core MMF at will and the sensor sensitivity can be easily tuned by selecting the refractive index of the liquid in the core of the device. The maximum sensitivity measured in our experiments is 20 nm/°C in the low-temperature regime up to 60 °C. To the best of our knowledge, to date, this is the largest sensitivity reported for fiber-based MMI temperature sensors.

  8. Model-based sensor diagnosis

    International Nuclear Information System (INIS)

    Milgram, J.; Dormoy, J.L.

    1994-09-01

    Running a nuclear power plant involves monitoring data provided by the installation's sensors. Operators and computerized systems then use these data to establish a diagnostic of the plant. However, the instrumentation system is complex, and is not immune to faults and failures. This paper presents a system for detecting sensor failures using a topological description of the installation and a set of component models. This model of the plant implicitly contains relations between sensor data. These relations must always be checked if all the components are functioning correctly. The failure detection task thus consists of checking these constraints. The constraints are extracted in two stages. Firstly, a qualitative model of their existence is built using structural analysis. Secondly, the models are formally handled according to the results of the structural analysis, in order to establish the constraints on the sensor data. This work constitutes an initial step in extending model-based diagnosis, as the information on which it is based is suspect. This work will be followed by surveillance of the detection system. When the instrumentation is assumed to be sound, the unverified constraints indicate errors on the plant model. (authors). 8 refs., 4 figs

  9. Satellite and Ground Based Monitoring of Aerosol Plumes

    International Nuclear Information System (INIS)

    Doyle, Martin; Dorling, Stephen

    2002-01-01

    Plumes of atmospheric aerosol have been studied using a range of satellite and ground-based techniques. The Sea-viewing WideField-of-view Sensor (SeaWiFS) has been used to observe plumes of sulphate aerosol and Saharan dust around the coast of the United Kingdom. Aerosol Optical Thickness (AOT) was retrieved from SeaWiFS for two events; a plume of Saharan dust transported over the United Kingdom from Western Africa and a period of elevated sulphate experienced over the Easternregion of the UK. Patterns of AOT are discussed and related to the synoptic and mesoscale weather conditions. Further observation of the sulphate aerosol event was undertaken using the Advanced Very High Resolution Radiometer instrument(AVHRR). Atmospheric back trajectories and weather conditions were studied in order to identify the meteorological conditions which led to this event. Co-located ground-based measurements of PM 10 and PM 2.5 were obtained for 4sites within the UK and PM 2.5/10 ratios were calculated in order to identify any unusually high or low ratios(indicating the dominant size fraction within the plume)during either of these events. Calculated percentiles ofPM 2.5/10 ratios during the 2 events examined show that these events were notable within the record, but were in noway unique or unusual in the context of a 3 yr monitoring record. Visibility measurements for both episodes have been examined and show that visibility degradation occurred during both the sulphate aerosol and Saharan dust episodes

  10. Zirconia-based solid state chemical gas sensors

    CERN Document Server

    Zhuiykov, S

    2000-01-01

    This paper presents an overview of chemical gas sensors, based on solid state technology, that are sensitive to environmental gases, such as O sub 2 , SO sub x , NO sub x , CO sub 2 and hydrocarbons. The paper is focussed on performance of electrochemical gas sensors that are based on zirconia as a solid electrolyte. The paper considers sensor structures and selection of electrode materials. Impact of interfaces on sensor performance is discussed. This paper also provides a brief overview of electrochemical properties of zirconia and their effect on sensor performance. Impact of auxiliary materials on sensors performance characteristics, such as sensitivity, selectivity, response time and recovery time, is also discussed. Dual gas sensors that can be applied for simultaneous monitoring of the concentration of both oxygen and other gas phase components, are briefly considered

  11. Graphene Chemical Sensor for Heliophysics Applications

    Science.gov (United States)

    Sultana, Mahmooda; Herrero, Fred; Khazanov, George

    2013-01-01

    Graphene is a single layer of carbon atoms that offer a unique set of advantages as a chemical sensor due to a number of its inherent properties. Graphene has been explored as a gas sensor for a variety of gases, and molecular sensitivity has been demonstrated by measuring the change in electrical properties due to the adsorption of target species. In this paper, we discuss the development of an array of chemical sensors based on graphene and its relevance to plasma physics due to its sensitivity to radical species such as oxonium, hydron and the corresponding neutrals. We briefly discuss the great impact such sensors will have on a number of heliophysics applications such as ground-based manifestations of space weather.

  12. Physical risk factors identification based on body sensor network combined to videotaping.

    Science.gov (United States)

    Vignais, Nicolas; Bernard, Fabien; Touvenot, Gérard; Sagot, Jean-Claude

    2017-11-01

    The aim of this study was to perform an ergonomic analysis of a material handling task by combining a subtask video analysis and a RULA computation, implemented continuously through a motion capture system combining inertial sensors and electrogoniometers. Five workers participated to the experiment. Seven inertial measurement units, placed on the worker's upper body (pelvis, thorax, head, arms, forearms), were implemented through a biomechanical model of the upper body to continuously provide trunk, neck, shoulder and elbow joint angles. Wrist joint angles were derived from electrogoniometers synchronized with the inertial measurement system. Worker's activity was simultaneously recorded using video. During post-processing, joint angles were used as inputs to a computationally implemented ergonomic evaluation based on the RULA method. Consequently a RULA score was calculated at each time step to characterize the risk of exposure of the upper body (right and left sides). Local risk scores were also computed to identify the anatomical origin of the exposure. Moreover, the video-recorded work activity was time-studied in order to classify and quantify all subtasks involved into the task. Results showed that mean RULA scores were at high risk for all participants (6 and 6.2 for right and left sides respectively). A temporal analysis demonstrated that workers spent most part of the work time at a RULA score of 7 (right: 49.19 ± 35.27%; left: 55.5 ± 29.69%). Mean local scores revealed that most exposed joints during the task were elbows, lower arms, wrists and hands. Elbows and lower arms were indeed at a high level of risk during the total time of a work cycle (100% for right and left sides). Wrist and hands were also exposed to a risky level for much of the period of work (right: 82.13 ± 7.46%; left: 77.85 ± 12.46%). Concerning the subtask analysis, subtasks called 'snow thrower', 'opening the vacuum sealer', 'cleaning' and 'storing' have been identified as

  13. Experimental Study of the Information Signal of Combined Shock, Tilt, and Motion Sensor Based on the 3-Axis MEMS-Accelerometer

    Directory of Open Access Journals (Sweden)

    S. A. Vasyukov

    2014-01-01

    range of accelerometer operation, as well as the accuracy of measuring acceleration, frequency of signal poll, and algorithm of filtration.The article gives recommendations for selecting the MEMS accelerometers to be used in combined shock, tilt, and motion sensors of modern car alarm systems.

  14. Il telerilevamento per la qualità dell'aria L'esperienza SENSORER

    Directory of Open Access Journals (Sweden)

    Marco Folegani

    2012-04-01

    Full Text Available Il monitoraggio della qualità dell'aria con tecniche di telerilevamento è noto da tempo negli ambienti scientifici ma considerato ancora con prudenza e perplessità dalle strutture istituzionali sia per il livello "accademico" delle applicazioni sia per la mancanza di una forte motivazione normativa nell'adottare nuovi metodi di monitoraggio. L'esperienza SENSORER ha l'ambizione di mostrare come si possono superare entrambe queste barriere. The remote sensing for air quality monitoring The SENSORER project.The satellite observations have proven their capabilities for re-mote sensing of atmospheric pollutants such as the Particulate Matter. But the advantage of global coverage, homogeneous quality and a relative good spatial resolution are counterbalanced by the limited temporal resolution and the cloud cover-age. The SENSORER project is just the last example of a web platform that thanks to a combination of satellite data with information from ground based sensors and models overcomes the limitations of each single observation method to provide better pollution maps to make better decisions.

  15. On-irrigator pasture soil moisture sensor

    International Nuclear Information System (INIS)

    Tan, Adrian Eng-Choon; Richards, Sean; Platt, Ian; Woodhead, Ian

    2017-01-01

    In this paper, we presented the development of a proximal soil moisture sensor that measured the soil moisture content of dairy pasture directly from the boom of an irrigator. The proposed sensor was capable of soil moisture measurements at an accuracy of  ±5% volumetric moisture content, and at meter scale ground area resolutions. The sensor adopted techniques from the ultra-wideband radar to enable measurements of ground reflection at resolutions that are smaller than the antenna beamwidth of the sensor. An experimental prototype was developed for field measurements. Extensive field measurements using the developed prototype were conducted on grass pasture at different ground conditions to validate the accuracy of the sensor in performing soil moisture measurements. (paper)

  16. Observability-Based Guidance and Sensor Placement

    Science.gov (United States)

    Hinson, Brian T.

    Control system performance is highly dependent on the quality of sensor information available. In a growing number of applications, however, the control task must be accomplished with limited sensing capabilities. This thesis addresses these types of problems from a control-theoretic point-of-view, leveraging system nonlinearities to improve sensing performance. Using measures of observability as an information quality metric, guidance trajectories and sensor distributions are designed to improve the quality of sensor information. An observability-based sensor placement algorithm is developed to compute optimal sensor configurations for a general nonlinear system. The algorithm utilizes a simulation of the nonlinear system as the source of input data, and convex optimization provides a scalable solution method. The sensor placement algorithm is applied to a study of gyroscopic sensing in insect wings. The sensor placement algorithm reveals information-rich areas on flexible insect wings, and a comparison to biological data suggests that insect wings are capable of acting as gyroscopic sensors. An observability-based guidance framework is developed for robotic navigation with limited inertial sensing. Guidance trajectories and algorithms are developed for range-only and bearing-only navigation that improve navigation accuracy. Simulations and experiments with an underwater vehicle demonstrate that the observability measure allows tuning of the navigation uncertainty.

  17. Intercomparison of ground-based ozone and NO2 measurements during the MANTRA 2004 campaign

    Directory of Open Access Journals (Sweden)

    K. Strong

    2007-11-01

    Full Text Available The MANTRA (Middle Atmosphere Nitrogen TRend Assessment 2004 campaign took place in Vanscoy, Saskatchewan, Canada (52° N, 107° W from 3 August to 15 September, 2004. In support of the main balloon launch, a suite of five zenith-sky and direct-Sun-viewing UV-visible ground-based spectrometers was deployed, primarily measuring ozone and NO2 total columns. Three Fourier transform spectrometers (FTSs that were part of the balloon payload also performed ground-based measurements of several species, including ozone. Ground-based measurements of ozone and NO2 differential slant column densities from the zenith-viewing UV-visible instruments are presented herein. They are found to partially agree within NDACC (Network for the Detection of Atmospheric Composition Change standards for instruments certified for process studies and satellite validation. Vertical column densities of ozone from the zenith-sky UV-visible instruments, the FTSs, a Brewer spectrophotometer, and ozonesondes are compared, and found to agree within the combined error estimates of the instruments (15%. NO2 vertical column densities from two of the UV-visible instruments are compared, and are also found to agree within combined error (15%.

  18. Track classification within wireless sensor network

    Science.gov (United States)

    Doumerc, Robin; Pannetier, Benjamin; Moras, Julien; Dezert, Jean; Canevet, Loic

    2017-05-01

    In this paper, we present our study on track classification by taking into account environmental information and target estimated states. The tracker uses several motion model adapted to different target dynamics (pedestrian, ground vehicle and SUAV, i.e. small unmanned aerial vehicle) and works in centralized architecture. The main idea is to explore both: classification given by heterogeneous sensors and classification obtained with our fusion module. The fusion module, presented in his paper, provides a class on each track according to track location, velocity and associated uncertainty. To model the likelihood on each class, a fuzzy approach is used considering constraints on target capability to move in the environment. Then the evidential reasoning approach based on Dempster-Shafer Theory (DST) is used to perform a time integration of this classifier output. The fusion rules are tested and compared on real data obtained with our wireless sensor network.In order to handle realistic ground target tracking scenarios, we use an autonomous smart computer deposited in the surveillance area. After the calibration step of the heterogeneous sensor network, our system is able to handle real data from a wireless ground sensor network. The performance of this system is evaluated in a real exercise for intelligence operation ("hunter hunt" scenario).

  19. Ground-based observations of exoplanet atmospheres

    NARCIS (Netherlands)

    Mooij, Ernst Johan Walter de

    2011-01-01

    This thesis focuses on the properties of exoplanet atmospheres. The results for ground-based near-infrared secondary eclipse observations of three different exoplanets, TrES-3b, HAT-P-1b and WASP-33b, are presented which have been obtained with ground-based telescopes as part of the GROUSE project.

  20. Development of a platform to combine sensor networks and home robots to improve fall detection in the home environment.

    Science.gov (United States)

    Della Toffola, Luca; Patel, Shyamal; Chen, Bor-rong; Ozsecen, Yalgin M; Puiatti, Alessandro; Bonato, Paolo

    2011-01-01

    Over the last decade, significant progress has been made in the development of wearable sensor systems for continuous health monitoring in the home and community settings. One of the main areas of application for these wearable sensor systems is in detecting emergency events such as falls. Wearable sensors like accelerometers are increasingly being used to monitor daily activities of individuals at a risk of falls, detect emergency events and send alerts to caregivers. However, such systems tend to have a high rate of false alarms, which leads to low compliance levels. Home robots can enable caregivers with the ability to quickly make an assessment and intervene if an emergency event is detected. This can provide an additional layer for detecting false positives, which can lead to improve compliance. In this paper, we present preliminary work on the development of a fall detection system based on a combination sensor networks and home robots. The sensor network architecture comprises of body worn sensors and ambient sensors distributed in the environment. We present the software architecture and conceptual design home robotic platform. We also perform preliminary characterization of the sensor network in terms of latencies and battery lifetime.

  1. Electrochemical and optical sugar sensors based on phenylboronic acid and its derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Egawa, Yuya; Seki, Toshinobu [Faculty of Pharmaceutical Sciences, Josai University, Keyakidai, Sakado, Saitama 350-0295 (Japan); Takahashi, Shigehiro [Graduate School of Pharmaceutical Sciecnes, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578 (Japan); Anzai, Jun-ichi, E-mail: junanzai@mail.pharm.tohoku.ac.jp [Graduate School of Pharmaceutical Sciecnes, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578 (Japan)

    2011-10-10

    indicators. Anthracene, pyranine, fluorescein, and rhodamine dyes have been used as fluorophores for fluorescence sensors. These dyes have been used in solution or immobilized in films, hydrogels, nanospheres, and quantum dots (QDs) to enhance the sensitivity. QDs-based sensors have been successfully applied for continuous monitoring of glucose in cells. Holographic glucose sensors have also been developed by combining PBA-immobilized hydrogels and photonic crystal colloidal arrays. Highlights: {yields} Phenylboronic acid-based optical and electrochemical sensors are reviewed. {yields} Dye-modified phenylboronic acids are useful as optical sugar sensor. {yields} Ferrocene-modified phenylboronic acids are used for electrochemical sugar detection. {yields} Phenylboronic acid is an alternative of enzymes for constructing sugar sensors.

  2. Electrochemical and optical sugar sensors based on phenylboronic acid and its derivatives

    International Nuclear Information System (INIS)

    Egawa, Yuya; Seki, Toshinobu; Takahashi, Shigehiro; Anzai, Jun-ichi

    2011-01-01

    indicators. Anthracene, pyranine, fluorescein, and rhodamine dyes have been used as fluorophores for fluorescence sensors. These dyes have been used in solution or immobilized in films, hydrogels, nanospheres, and quantum dots (QDs) to enhance the sensitivity. QDs-based sensors have been successfully applied for continuous monitoring of glucose in cells. Holographic glucose sensors have also been developed by combining PBA-immobilized hydrogels and photonic crystal colloidal arrays. Highlights: → Phenylboronic acid-based optical and electrochemical sensors are reviewed. → Dye-modified phenylboronic acids are useful as optical sugar sensor. → Ferrocene-modified phenylboronic acids are used for electrochemical sugar detection. → Phenylboronic acid is an alternative of enzymes for constructing sugar sensors.

  3. Real-Time Identification of Smoldering and Flaming Combustion Phases in Forest Using a Wireless Sensor Network-Based Multi-Sensor System and Artificial Neural Network.

    Science.gov (United States)

    Yan, Xiaofei; Cheng, Hong; Zhao, Yandong; Yu, Wenhua; Huang, Huan; Zheng, Xiaoliang

    2016-08-04

    Diverse sensing techniques have been developed and combined with machine learning method for forest fire detection, but none of them referred to identifying smoldering and flaming combustion phases. This study attempts to real-time identify different combustion phases using a developed wireless sensor network (WSN)-based multi-sensor system and artificial neural network (ANN). Sensors (CO, CO₂, smoke, air temperature and relative humidity) were integrated into one node of WSN. An experiment was conducted using burning materials from residual of forest to test responses of each node under no, smoldering-dominated and flaming-dominated combustion conditions. The results showed that the five sensors have reasonable responses to artificial forest fire. To reduce cost of the nodes, smoke, CO₂ and temperature sensors were chiefly selected through correlation analysis. For achieving higher identification rate, an ANN model was built and trained with inputs of four sensor groups: smoke; smoke and CO₂; smoke and temperature; smoke, CO₂ and temperature. The model test results showed that multi-sensor input yielded higher predicting accuracy (≥82.5%) than single-sensor input (50.9%-92.5%). Based on these, it is possible to reduce the cost with a relatively high fire identification rate and potential application of the system can be tested in future under real forest condition.

  4. Lightning-Sensor Data Help In Understanding Thunderstorms

    Science.gov (United States)

    Goodman, Steven J.

    1992-01-01

    NASA technical memorandum discusses research on use of data from network of ground-based magnetic direction-finding ground-strike lightning sensors to diagnose and predict occurrence and evolution of thunderstorms. Purposes of study to explore applicability and limitations of extrapolation techniques used to generate forecasts from data; to examine physically-based, nonlinear mathematical models for applicability to lightning-forecast problem; and to determine valid extrapolation ranges of such models for various weather scenarios.

  5. Introducing the VISAGE project - Visualization for Integrated Satellite, Airborne, and Ground-based data Exploration

    Science.gov (United States)

    Gatlin, P. N.; Conover, H.; Berendes, T.; Maskey, M.; Naeger, A. R.; Wingo, S. M.

    2017-12-01

    A key component of NASA's Earth observation system is its field experiments, for intensive observation of particular weather phenomena, or for ground validation of satellite observations. These experiments collect data from a wide variety of airborne and ground-based instruments, on different spatial and temporal scales, often in unique formats. The field data are often used with high volume satellite observations that have very different spatial and temporal coverage. The challenges inherent in working with such diverse datasets make it difficult for scientists to rapidly collect and analyze the data for physical process studies and validation of satellite algorithms. The newly-funded VISAGE project will address these issues by combining and extending nascent efforts to provide on-line data fusion, exploration, analysis and delivery capabilities. A key building block is the Field Campaign Explorer (FCX), which allows users to examine data collected during field campaigns and simplifies data acquisition for event-based research. VISAGE will extend FCX's capabilities beyond interactive visualization and exploration of coincident datasets, to provide interrogation of data values and basic analyses such as ratios and differences between data fields. The project will also incorporate new, higher level fused and aggregated analysis products from the System for Integrating Multi-platform data to Build the Atmospheric column (SIMBA), which combines satellite and ground-based observations into a common gridded atmospheric column data product; and the Validation Network (VN), which compiles a nationwide database of coincident ground- and satellite-based radar measurements of precipitation for larger scale scientific analysis. The VISAGE proof-of-concept will target "golden cases" from Global Precipitation Measurement Ground Validation campaigns. This presentation will introduce the VISAGE project, initial accomplishments and near term plans.

  6. Development of a soft-sensor based on multi-wavelength fluorescence spectroscopy and a dynamic metabolic model for monitoring mammalian cell cultures.

    Science.gov (United States)

    Ohadi, Kaveh; Legge, Raymond L; Budman, Hector M

    2015-01-01

    A soft-sensor based on an Extended Kalman Filter (EKF) that combines data obtained using a fluorescence-based soft-sensor with a dynamic mechanistic model, was investigated as a tool for continuous monitoring of a Chinese hamster ovary (CHO) cell cultivation process. A standalone fluorescence based soft-sensor, which uses a combination of an empirical multivariate statistical model and measured spectra, was designed for predicting key culture variables including viable and dead cells, recombinant protein, glucose, and ammonia concentrations. The standalone fluorescence sensor was then combined with a dynamic mechanistic model within an EKF framework, for improving the prediction accuracy and generating predictions in-between sampling instances. The dynamic model used for the EKF framework was based on a structured metabolic flux analysis and mass balances. In order to calibrate the fluorescence-based empirical model and the dynamic mechanistic model, cells were grown in batch mode with different initial glucose and glutamine concentrations. To mitigate the uncertainty associated with the model structure and parameters, non-stationary disturbances were accounted for in the EKF by parameter-adaptation. It was demonstrated that the implementation of the EKF along with the dynamic model could improve the accuracy of the fluorescence-based predictions at the sampling instances. Additionally, it was shown that the major advantage of the EKF-based soft-sensor, compared to the standalone fluorescence-based counterpart, was its capability to track the temporal evolution of key process variables between measurement instances obtained by the fluorescence-based soft-sensor. This is crucial for designing control strategies of CHO cell cultures with the aim of guaranteeing product quality. © 2014 Wiley Periodicals, Inc.

  7. NO2 DOAS measurements from ground and space: comparison of ground based measurements and OMI data in Mexico City

    Science.gov (United States)

    Rivera, C.; Stremme, W.; Grutter, M.

    2012-04-01

    The combination of satellite data and ground based measurements can provide valuable information about atmospheric chemistry and air quality. In this work we present a comparison between measured ground based NO2 differential columns at the Universidad Nacional Autónoma de México (UNAM) in Mexico City, using the Differential Optical Absorption Spectroscopy (DOAS) technique and NO2 total columns measured by the Ozone Monitoring Instrument (OMI) onboard the Aura satellite using the same measurement technique. From these data, distribution maps of average NO2 above the Mexico basin were constructed and hot spots inside the city could be identified. In addition, a clear footprint was detected from the Tula industrial area, ~50 km northwest of Mexico City, where a refinery, a power plant and other industries are located. A less defined footprint was identified in the Cuernavaca basin, South of Mexico City, and the nearby cities of Toluca and Puebla do not present strong enhancements in the NO2 total columns. With this study we expect to cross-validate space and ground measurements and provide useful information for future studies.

  8. Adaptive Sensing Based on Profiles for Sensor Systems

    Directory of Open Access Journals (Sweden)

    Yoshiteru Ishida

    2009-10-01

    Full Text Available This paper proposes a profile-based sensing framework for adaptive sensor systems based on models that relate possibly heterogeneous sensor data and profiles generated by the models to detect events. With these concepts, three phases for building the sensor systems are extracted from two examples: a combustion control sensor system for an automobile engine, and a sensor system for home security. The three phases are: modeling, profiling, and managing trade-offs. Designing and building a sensor system involves mapping the signals to a model to achieve a given mission.

  9. Multi-image acquisition-based distance sensor using agile laser spot beam.

    Science.gov (United States)

    Riza, Nabeel A; Amin, M Junaid

    2014-09-01

    We present a novel laser-based distance measurement technique that uses multiple-image-based spatial processing to enable distance measurements. Compared with the first-generation distance sensor using spatial processing, the modified sensor is no longer hindered by the classic Rayleigh axial resolution limit for the propagating laser beam at its minimum beam waist location. The proposed high-resolution distance sensor design uses an electronically controlled variable focus lens (ECVFL) in combination with an optical imaging device, such as a charged-coupled device (CCD), to produce and capture different laser spot size images on a target with these beam spot sizes different from the minimal spot size possible at this target distance. By exploiting the unique relationship of the target located spot sizes with the varying ECVFL focal length for each target distance, the proposed distance sensor can compute the target distance with a distance measurement resolution better than the axial resolution via the Rayleigh resolution criterion. Using a 30 mW 633 nm He-Ne laser coupled with an electromagnetically actuated liquid ECVFL, along with a 20 cm focal length bias lens, and using five spot images captured per target position by a CCD-based Nikon camera, a proof-of-concept proposed distance sensor is successfully implemented in the laboratory over target ranges from 10 to 100 cm with a demonstrated sub-cm axial resolution, which is better than the axial Rayleigh resolution limit at these target distances. Applications for the proposed potentially cost-effective distance sensor are diverse and include industrial inspection and measurement and 3D object shape mapping and imaging.

  10. Development of Mine Explosion Ground Truth Smart Sensors

    Science.gov (United States)

    2011-09-01

    interest. The two candidates are the GS11-D by Oyo Geospace that is used extensively in seismic monitoring of geothermal fields and the Sensor Nederland SM...Technologies 853 Figure 4. Our preferred sensors and processor for the GTMS. (a) Sensor Nederland SM-6 geophone with emplacement spike. (b

  11. The Thermal Infrared Sensor onboard NASA's Mars 2020 Mission

    Science.gov (United States)

    Martinez, G.; Perez-Izquierdo, J.; Sebastian, E.; Ramos, M.; Bravo, A.; Mazo, M.; Rodriguez-Manfredi, J. A.

    2017-12-01

    NASA's Mars 2020 rover mission is scheduled for launch in July/August 2020 and will address key questions about the potential for life on Mars. The Mars Environmental Dynamics Analyzer (MEDA) is one of the seven instruments onboard the rover [1] and has been designed to assess the environmental conditions across the rover traverse. MEDA will extend the current record of in-situ meteorological measurements at the surface [2] to other locations on Mars. The Thermal InfraRed Sensor (TIRS) [3] is one of the six sensors comprising MEDA. TIRS will use three downward-looking channels to measure (1) the surface skin temperature (with high heritage from the Rover Environmental Monitoring Station onboard the Mars Science Laboratory mission [4]), (2) the upwelling thermal infrared radiation from the surface and (3) the reflected solar radiation at the surface, and two upward-looking channels to measure the (4) downwelling thermal infrared radiation at the surface and (5) the atmospheric temperature. In combination with other MEDA's sensors, TIRS will allow the quantification of the surface energy budget [5] and the determination of key geophysical properties of the terrain such as the albedo and thermal inertia with an unprecedented spatial resolution. Here we present a general description of the TIRS, with focus on its scientific requirements and results from field campaigns showing the performance of the different channels. References:[1] Rodríguez-Manfredi, J. A. et al. (2014), MEDA: An environmental and meteorological package for Mars 2020, LPSC, 45, 2837. [2] Martínez, G.M. et al. (2017), The Modern Near-Surface Martian Climate: A Review of In-situ Meteorological Data from Viking to Curiosity, Space Science Reviews, 1-44. [3] Pérez-Izquierdo, J. et al. (2017), The Thermal Infrared Sensor (TIRS) of the Mars Environmental Dynamics Analyzer (MEDA) Instrument onboard Mars 2020, IEEE. [4] Sebastián, E. et al. (2010), The Rover Environmental Monitoring Station Ground

  12. Object Recognition and Localization: The Role of Tactile Sensors

    Directory of Open Access Journals (Sweden)

    Achint Aggarwal

    2014-02-01

    Full Text Available Tactile sensors, because of their intrinsic insensitivity to lighting conditions and water turbidity, provide promising opportunities for augmenting the capabilities of vision sensors in applications involving object recognition and localization. This paper presents two approaches for haptic object recognition and localization for ground and underwater environments. The first approach called Batch Ransac and Iterative Closest Point augmented Particle Filter (BRICPPF is based on an innovative combination of particle filters, Iterative-Closest-Point algorithm, and a feature-based Random Sampling and Consensus (RANSAC algorithm for database matching. It can handle a large database of 3D-objects of complex shapes and performs a complete six-degree-of-freedom localization of static objects. The algorithms are validated by experimentation in ground and underwater environments using real hardware. To our knowledge this is the first instance of haptic object recognition and localization in underwater environments. The second approach is biologically inspired, and provides a close integration between exploration and recognition. An edge following exploration strategy is developed that receives feedback from the current state of recognition. A recognition by parts approach is developed which uses the BRICPPF for object sub-part recognition. Object exploration is either directed to explore a part until it is successfully recognized, or is directed towards new parts to endorse the current recognition belief. This approach is validated by simulation experiments.

  13. Nanophotonic Image Sensors.

    Science.gov (United States)

    Chen, Qin; Hu, Xin; Wen, Long; Yu, Yan; Cumming, David R S

    2016-09-01

    The increasing miniaturization and resolution of image sensors bring challenges to conventional optical elements such as spectral filters and polarizers, the properties of which are determined mainly by the materials used, including dye polymers. Recent developments in spectral filtering and optical manipulating techniques based on nanophotonics have opened up the possibility of an alternative method to control light spectrally and spatially. By integrating these technologies into image sensors, it will become possible to achieve high compactness, improved process compatibility, robust stability and tunable functionality. In this Review, recent representative achievements on nanophotonic image sensors are presented and analyzed including image sensors with nanophotonic color filters and polarizers, metamaterial-based THz image sensors, filter-free nanowire image sensors and nanostructured-based multispectral image sensors. This novel combination of cutting edge photonics research and well-developed commercial products may not only lead to an important application of nanophotonics but also offer great potential for next generation image sensors beyond Moore's Law expectations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Smart aggregate based damage detection of circular RC columns under cyclic combined loading

    International Nuclear Information System (INIS)

    Moslehy, Yashar; Belarbi, Abdeldjelil; Mo, Y L; Gu, Haichang; Song, Gangbing

    2010-01-01

    Structural health monitoring is an important issue for the maintenance of large-scale civil infrastructures, especially for bridge columns. In this paper, an innovative piezoceramic-based approach is developed for the structural health monitoring of reinforced concrete columns. An innovative piezoceramic-based device, the smart aggregate, is utilized as a transducer for the purpose of health monitoring. To investigate the seismic behavior of reinforced concrete (RC) bridge columns, structural health monitoring tests were performed on two bridge columns under combined reversed cyclic loading at the Missouri University of Science and Technology. The proposed smart aggregate based approach successfully evaluated the health status of concrete columns during the loading procedure. Sensor energy plots and 3D normalized sensor energy plots demonstrated that the damage inside attenuated the transmitted energy. The wavelet packet based damage index and sensor history damage index evaluate the damage development in concrete columns under cyclic loading

  15. Resource Discovery in Activity-Based Sensor Networks

    DEFF Research Database (Denmark)

    Bucur, Doina; Bardram, Jakob

    This paper proposes a service discovery protocol for sensor networks that is specifically tailored for use in humancentered pervasive environments. It uses the high-level concept of computational activities (as logical bundles of data and resources) to give sensors in Activity-Based Sensor Networks...... (ABSNs) knowledge about their usage even at the network layer. ABSN redesigns classical network-level service discovery protocols to include and use this logical structuring of the network for a more practically applicable service discovery scheme. Noting that in practical settings activity-based sensor...

  16. Reconciling Ground-Based and Space-Based Estimates of the Frequency of Occurrence and Radiative Effect of Clouds around Darwin, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Protat, Alain; Young, Stuart; McFarlane, Sally A.; L' Ecuyer, Tristan; Mace, Gerald G.; Comstock, Jennifer M.; Long, Charles N.; Berry, Elizabeth; Delanoe, Julien

    2014-02-01

    The objective of this paper is to investigate whether estimates of the cloud frequency of occurrence and associated cloud radiative forcing as derived from ground-based and satellite active remote sensing and radiative transfer calculations can be reconciled over a well instrumented active remote sensing site located in Darwin, Australia, despite the very different viewing geometry and instrument characteristics. It is found that the ground-based radar-lidar combination at Darwin does not detect most of the cirrus clouds above 10 km (due to limited lidar detection capability and signal obscuration by low-level clouds) and that the CloudSat radar - Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) combination underreports the hydrometeor frequency of occurrence below 2 km height, due to instrument limitations at these heights. The radiative impact associated with these differences in cloud frequency of occurrence is large on the surface downwelling shortwave fluxes (ground and satellite) and the top-of atmosphere upwelling shortwave and longwave fluxes (ground). Good agreement is found for other radiative fluxes. Large differences in radiative heating rate as derived from ground and satellite radar-lidar instruments and RT calculations are also found above 10 km (up to 0.35 Kday-1 for the shortwave and 0.8 Kday-1 for the longwave). Given that the ground-based and satellite estimates of cloud frequency of occurrence and radiative impact cannot be fully reconciled over Darwin, caution should be exercised when evaluating the representation of clouds and cloud-radiation interactions in large-scale models and limitations of each set of instrumentation should be considered when interpreting model-observations differences.

  17. Pyrometer model based on sensor physical structure and thermal operation

    International Nuclear Information System (INIS)

    Sebastian, Eduardo; Armiens, Carlos; Gomez-Elvira, Javier

    2010-01-01

    This paper proposes a new simplified thermal model for pyrometers, which takes into account both their internal and external physical structure and operation. The model is experimentally tested on the REMS GTS, an instrument for measuring ground temperature, which is part of the payload of the NASA MSL mission to Mars. The proposed model is based on an energy balance equation that represents the heat fluxes exchanged between sensor elements through radiation, conduction and convection. Despite being mathematically more complex than the more commonly used model, the proposed model makes it possible to design a methodology to compensate the effects of sensor spatial thermal gradients. The paper includes a practical methodology for identifying model constants, which is part of the GTS instrument calibration plan and uses a differential approach to avoid setup errors. Experimental results of the model identification methodology and a target temperature measurement performance after identification has been made are reported. Results demonstrate the good behaviour of the model, with errors below 0.15 deg. C in target temperature estimates.

  18. Combination Adaptive Traffic Algorithm and Coordinated Sleeping in Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    M. Udin Harun Al Rasyid

    2014-12-01

    Full Text Available Wireless sensor network (WSN uses a battery as its primary power source, so that WSN will be limited to battery power for long operations. The WSN should be able to save the energy consumption in order to operate in a long time.WSN has the potential to be the future of wireless communications solutions. WSN are small but has a variety of functions that can help human life. WSN has the wide variety of sensors and can communicate quickly making it easier for people to obtain information accurately and quickly. In this study, we combine adaptive traffic algorithms and coordinated sleeping as power‐efficient WSN solution. We compared the performance of our proposed ideas combination adaptive traffic and coordinated sleeping algorithm with non‐adaptive scheme. From the simulation results, our proposed idea has good‐quality data transmission and more efficient in energy consumption, but it has higher delay than that of non‐adaptive scheme. Keywords:WSN,adaptive traffic,coordinated sleeping,beacon order,superframe order.

  19. 100 nm scale low-noise sensors based on aligned carbon nanotube networks: overcoming the fundamental limitation of network-based sensors

    Science.gov (United States)

    Lee, Minbaek; Lee, Joohyung; Kim, Tae Hyun; Lee, Hyungwoo; Lee, Byung Yang; Park, June; Jhon, Young Min; Seong, Maeng-Je; Hong, Seunghun

    2010-02-01

    Nanoscale sensors based on single-walled carbon nanotube (SWNT) networks have been considered impractical due to several fundamental limitations such as a poor sensitivity and small signal-to-noise ratio. Herein, we present a strategy to overcome these fundamental problems and build highly-sensitive low-noise nanoscale sensors simply by controlling the structure of the SWNT networks. In this strategy, we prepared nanoscale width channels based on aligned SWNT networks using a directed assembly strategy. Significantly, the aligned network-based sensors with narrower channels exhibited even better signal-to-noise ratio than those with wider channels, which is opposite to conventional random network-based sensors. As a proof of concept, we demonstrated 100 nm scale low-noise sensors to detect mercury ions with the detection limit of ~1 pM, which is superior to any state-of-the-art portable detection system and is below the allowable limit of mercury ions in drinking water set by most government environmental protection agencies. This is the first demonstration of 100 nm scale low-noise sensors based on SWNT networks. Considering the increased interests in high-density sensor arrays for healthcare and environmental protection, our strategy should have a significant impact on various industrial applications.

  20. 100 nm scale low-noise sensors based on aligned carbon nanotube networks: overcoming the fundamental limitation of network-based sensors

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Minbaek; Lee, Joohyung; Kim, Tae Hyun; Lee, Hyungwoo; Lee, Byung Yang; Hong, Seunghun [Department of Physics and Astronomy, Seoul National University, Shilim-Dong, Kwanak-Gu, Seoul 151-742 (Korea, Republic of); Park, June; Seong, Maeng-Je [Department of Physics, Chung-Ang University, Heukseok-Dong, Dongjak-Gu, Seoul 156-756 (Korea, Republic of); Jhon, Young Min, E-mail: mseong@cau.ac.kr, E-mail: shong@phya.snu.ac.kr [Korea Institute of Science and Technology, Hawolgok-Dong, Seongbuk-Gu, Seoul 136-791 (Korea, Republic of)

    2010-02-05

    Nanoscale sensors based on single-walled carbon nanotube (SWNT) networks have been considered impractical due to several fundamental limitations such as a poor sensitivity and small signal-to-noise ratio. Herein, we present a strategy to overcome these fundamental problems and build highly-sensitive low-noise nanoscale sensors simply by controlling the structure of the SWNT networks. In this strategy, we prepared nanoscale width channels based on aligned SWNT networks using a directed assembly strategy. Significantly, the aligned network-based sensors with narrower channels exhibited even better signal-to-noise ratio than those with wider channels, which is opposite to conventional random network-based sensors. As a proof of concept, we demonstrated 100 nm scale low-noise sensors to detect mercury ions with the detection limit of {approx}1 pM, which is superior to any state-of-the-art portable detection system and is below the allowable limit of mercury ions in drinking water set by most government environmental protection agencies. This is the first demonstration of 100 nm scale low-noise sensors based on SWNT networks. Considering the increased interests in high-density sensor arrays for healthcare and environmental protection, our strategy should have a significant impact on various industrial applications.

  1. 100 nm scale low-noise sensors based on aligned carbon nanotube networks: overcoming the fundamental limitation of network-based sensors

    International Nuclear Information System (INIS)

    Lee, Minbaek; Lee, Joohyung; Kim, Tae Hyun; Lee, Hyungwoo; Lee, Byung Yang; Hong, Seunghun; Park, June; Seong, Maeng-Je; Jhon, Young Min

    2010-01-01

    Nanoscale sensors based on single-walled carbon nanotube (SWNT) networks have been considered impractical due to several fundamental limitations such as a poor sensitivity and small signal-to-noise ratio. Herein, we present a strategy to overcome these fundamental problems and build highly-sensitive low-noise nanoscale sensors simply by controlling the structure of the SWNT networks. In this strategy, we prepared nanoscale width channels based on aligned SWNT networks using a directed assembly strategy. Significantly, the aligned network-based sensors with narrower channels exhibited even better signal-to-noise ratio than those with wider channels, which is opposite to conventional random network-based sensors. As a proof of concept, we demonstrated 100 nm scale low-noise sensors to detect mercury ions with the detection limit of ∼1 pM, which is superior to any state-of-the-art portable detection system and is below the allowable limit of mercury ions in drinking water set by most government environmental protection agencies. This is the first demonstration of 100 nm scale low-noise sensors based on SWNT networks. Considering the increased interests in high-density sensor arrays for healthcare and environmental protection, our strategy should have a significant impact on various industrial applications.

  2. Combination of a fast white-light interferometer with a phase shifting interferometric line sensor for form measurements of precision components

    Science.gov (United States)

    Laubach, Sören; Ehret, Gerd; Riebling, Jörg; Lehmann, Peter

    2017-06-01

    By means of an interferometric line sensor system, the form of a specimen can be measured by stitching several overlapping circular subapertures to form one 3D topography. This concept is very flexible and can be adapted to many different specimen geometries. The sensor is based on a Michelson interferometer configuration that consists of a rapidly oscillating reference mirror in combination with a high-speed line-scan camera. Due to the overlapping areas, movement errors of the scan axes can be corrected. In order to automatically adjust the line sensor in such a way that it is perpendicular to the measurement surface at a fixed working distance, a white-light interferometer was included in the line-based form-measuring system. By means of a fast white-light scan, the optimum angle of the sensor (with respect to the surface of the specimen) is determined in advance, before scanning the specimen using the line-based sinusoidal phase shifting interferometer. This produces accurate measurement results and makes it possible to also measure non-rotational specimens. In this paper, the setup of the line-based form-measuring system is introduced and the measurement strategy of the sensor adjustment using an additional white-light interferometer is presented. Furthermore, the traceability chain of the system and the main error influences are discussed. Examples of form measurement results are shown.

  3. Water-Cut Sensor System

    KAUST Repository

    Karimi, Muhammad Akram

    2018-01-11

    Provided in some embodiments is a method of manufacturing a pipe conformable water-cut sensors system. Provided in some embodiments is method for manufacturing a water-cut sensor system that includes providing a helical T-resonator, a helical ground conductor, and a separator at an exterior of a cylindrical pipe. The helical T-resonator including a feed line, and a helical open shunt stub conductively coupled to the feed line. The helical ground conductor including a helical ground plane opposite the helical open shunt stub and a ground ring conductively coupled to the helical ground plane. The feed line overlapping at least a portion of the ground ring, and the separator disposed between the feed line and the portion of the ground ring overlapped by the feed line to electrically isolate the helical T-resonator from the helical ground conductor.

  4. PhoneSat: Ground Testing of a Phone-Based Prototype Bus

    Science.gov (United States)

    Felix, Carmen; Howard, Benjamin; Reyes, Matthew; Snarskiy, Fedor; Hickman, Ryan; Boshuizen, Christopher; Marshall, William

    2010-01-01

    Most of the key capabilities that are requisite of a satellite bus are housed in today's smart phones. PhoneSat refers to an initiative to build a ground-based prototype vehicle that could all the basic functionality of a satellite, including attitude control, using a smart Phone as its central hardware. All components used were also low cost Commercial off the Shelf (COTS). In summer 2009, an initial prototype was created using the LEGO Mindstorm toolkit demonstrating simple attitude control. Here we report on a follow up initiative to design, build and test a vehicle based on the Google s smart phone Nexus One. The report includes results from initial thermal-vacuum chamber tests and low altitude sub-orbital rocket flights which show that, at least for short durations, the Nexus One phone is able to withstand key aspects of the space environment without failure. We compare the sensor data from the Phone's accelerometers and magnetometers with that of an external microelectronic inertial measurement unit.

  5. Spatial Frequency Multiplexing of Fiber-Optic Interferometric Refractive Index Sensors Based on Graded-Index Multimode Fibers

    Science.gov (United States)

    Liu, Li; Gong, Yuan; Wu, Yu; Zhao, Tian; Wu, Hui-Juan; Rao, Yun-Jiang

    2012-01-01

    Fiber-optic interferometric sensors based on graded-index multimode fibers have very high refractive-index sensitivity, as we previously demonstrated. In this paper, spatial-frequency multiplexing of this type of fiber-optic refractive index sensors is investigated. It is estimated that multiplexing of more than 10 such sensors is possible. In the multiplexing scheme, one of the sensors is used to investigate the refractive index and temperature responses. The fast Fourier transform (FFT) of the combined reflective spectra is analyzed. The intensity of the FFT spectra is linearly related with the refractive index and is not sensitive to the temperature.

  6. Integrated organic electronic based optochemical sensors using polarization filters

    International Nuclear Information System (INIS)

    Kraker, Elke; Haase, Anja; Lamprecht, Bernhard; Jakopic, Georg; Konrad, Christian; Koestler, Stefan

    2008-01-01

    A compact, integrated photoluminescence based oxygen and pH sensor, utilizing an organic light emitting device (OLED) as the light source and an organic photodiode (OPD) as the detection unit, is described. The main challenge in such an integrated sensor is the suppression of the excitation light at the detector, which is typically by many orders of magnitude higher in intensity than the emitted fluorescence. In our approach, we refrain from utilizing edge filters which require narrow band excitation sources and dyes with an adequate large Stokes shift. We rather developed an integrated sensor concept relying on two polarizers to separate the emission and excitation light. One polarizer is located right after the OLED, while the other one, oriented at 90 deg. to the first, is placed in front of the OPD. The main advantage of this solution is that any combination of excitation and emission light is acceptable, even if the two signals overlap spectrally. This is especially important for the use of OLEDs as the excitation sources, as these devices typically exhibit a broad spectral emission

  7. LYAPUNOV-Based Sensor Failure Detection and Recovery for the Reverse Water Gas Shift Process

    Science.gov (United States)

    Haralambous, Michael G.

    2002-01-01

    Livingstone, a model-based AI software system, is planned for use in the autonomous fault diagnosis, reconfiguration, and control of the oxygen-producing reverse water gas shift (RWGS) process test-bed located in the Applied Chemistry Laboratory at KSC. In this report the RWGS process is first briefly described and an overview of Livingstone is given. Next, a Lyapunov-based approach for detecting and recovering from sensor failures, differing significantly from that used by Livingstone, is presented. In this new method, models used are in t e m of the defining differential equations of system components, thus differing from the qualitative, static models used by Livingstone. An easily computed scalar inequality constraint, expressed in terms of sensed system variables, is used to determine the existence of sensor failures. In the event of sensor failure, an observer/estimator is used for determining which sensors have failed. The theory underlying the new approach is developed. Finally, a recommendation is made to use the Lyapunov-based approach to complement the capability of Livingstone and to use this combination in the RWGS process.

  8. Algorithms exploiting ultrasonic sensors for subject classification

    Science.gov (United States)

    Desai, Sachi; Quoraishee, Shafik

    2009-09-01

    Proposed here is a series of techniques exploiting micro-Doppler ultrasonic sensors capable of characterizing various detected mammalian targets based on their physiological movements captured a series of robust features. Employed is a combination of unique and conventional digital signal processing techniques arranged in such a manner they become capable of classifying a series of walkers. These processes for feature extraction develops a robust feature space capable of providing discrimination of various movements generated from bipeds and quadrupeds and further subdivided into large or small. These movements can be exploited to provide specific information of a given signature dividing it in a series of subset signatures exploiting wavelets to generate start/stop times. After viewing a series spectrograms of the signature we are able to see distinct differences and utilizing kurtosis, we generate an envelope detector capable of isolating each of the corresponding step cycles generated during a walk. The walk cycle is defined as one complete sequence of walking/running from the foot pushing off the ground and concluding when returning to the ground. This time information segments the events that are readily seen in the spectrogram but obstructed in the temporal domain into individual walk sequences. This walking sequence is then subsequently translated into a three dimensional waterfall plot defining the expected energy value associated with the motion at particular instance of time and frequency. The value is capable of being repeatable for each particular class and employable to discriminate the events. Highly reliable classification is realized exploiting a classifier trained on a candidate sample space derived from the associated gyrations created by motion from actors of interest. The classifier developed herein provides a capability to classify events as an adult humans, children humans, horses, and dogs at potentially high rates based on the tested sample

  9. Photodiode-based cutting interruption sensor for near-infrared lasers.

    Science.gov (United States)

    Adelmann, B; Schleier, M; Neumeier, B; Hellmann, R

    2016-03-01

    We report on a photodiode-based sensor system to detect cutting interruptions during laser cutting with a fiber laser. An InGaAs diode records the thermal radiation from the process zone with a ring mirror and optical filter arrangement mounted between a collimation unit and a cutting head. The photodiode current is digitalized with a sample rate of 20 kHz and filtered with a Chebyshev Type I filter. From the measured signal during the piercing, a threshold value is calculated. When the diode signal exceeds this threshold during cutting, a cutting interruption is indicated. This method is applied to sensor signals from cutting mild steel, stainless steel, and aluminum, as well as different material thicknesses and also laser flame cutting, showing the possibility to detect cutting interruptions in a broad variety of applications. In a series of 83 incomplete cuts, every cutting interruption is successfully detected (alpha error of 0%), while no cutting interruption is reported in 266 complete cuts (beta error of 0%). With this remarkable high detection rate and low error rate, the possibility to work with different materials and thicknesses in combination with the easy mounting of the sensor unit also to existing cutting machines highlight the enormous potential for this sensor system in industrial applications.

  10. A novel technique for extracting clouds base height using ground based imaging

    Directory of Open Access Journals (Sweden)

    E. Hirsch

    2011-01-01

    Full Text Available The height of a cloud in the atmospheric column is a key parameter in its characterization. Several remote sensing techniques (passive and active, either ground-based or on space-borne platforms and in-situ measurements are routinely used in order to estimate top and base heights of clouds. In this article we present a novel method that combines thermal imaging from the ground and sounded wind profile in order to derive the cloud base height. This method is independent of cloud types, making it efficient for both low boundary layer and high clouds. In addition, using thermal imaging ensures extraction of clouds' features during daytime as well as at nighttime. The proposed technique was validated by comparison to active sounding by ceilometers (which is a standard ground based method, to lifted condensation level (LCL calculations, and to MODIS products obtained from space. As all passive remote sensing techniques, the proposed method extracts only the height of the lowest cloud layer, thus upper cloud layers are not detected. Nevertheless, the information derived from this method can be complementary to space-borne cloud top measurements when deep-convective clouds are present. Unlike techniques such as LCL, this method is not limited to boundary layer clouds, and can extract the cloud base height at any level, as long as sufficient thermal contrast exists between the radiative temperatures of the cloud and its surrounding air parcel. Another advantage of the proposed method is its simplicity and modest power needs, making it particularly suitable for field measurements and deployment at remote locations. Our method can be further simplified for use with visible CCD or CMOS camera (although nighttime clouds will not be observed.

  11. Integrated active fire retrievals and biomass burning emissions using complementary near-coincident ground, airborne and spaceborne sensor data

    Science.gov (United States)

    Wilfrid Schroeder; Evan Ellicott; Charles Ichoku; Luke Ellison; Matthew B. Dickinson; Roger D. Ottmar; Craig Clements; Dianne Hall; Vincent Ambrosia; Robert. Kremens

    2013-01-01

    Ground, airborne and spaceborne data were collected for a 450 ha prescribed fire implemented on 18 October 2011 at the Henry W. Coe State Park in California. The integration of various data elements allowed near-coincident active fire retrievals to be estimated. The Autonomous Modular Sensor-Wildfire (AMS) airborne multispectral imaging system was used as a bridge...

  12. Thermophysical Properties Along Curiosity's Traverse in Gale Crater, Mars, Derived from the REMS Ground Temperature Sensor

    Science.gov (United States)

    Vasavada, Ashwin R.; Piqueux, Sylvain; Lewis, Kevin W.; Lemmon, Mark T.; Smith, Michael Doyle

    2016-01-01

    The REMS instrument onboard the Mars Science Laboratory rover, Curiosity, has measured ground temperature nearly continuously at hourly intervals for two Mars years. Coverage of the entire diurnal cycle at 1 Hz is available every few martian days. We compare these measurements with predictions of surface atmosphere thermal models to derive the apparent thermal inertia and thermally derived albedo along the rovers traverse after accounting for the radiative effects of atmospheric water ice during fall and winter, as is necessary to match the measured seasonal trend. The REMS measurements can distinguish between active sand, other loose materials, mudstone, and sandstone based on their thermophysical properties. However, the apparent thermal inertias of bedrock dominated surfaces [approx. 350-550 J m(exp. -2) K(exp. -1 s(exp. -1/2 )] are lower than expected. We use rover imagery and the detailed shape of the diurnal ground temperature curve to explore whether lateral or vertical heterogeneity in the surface materials within the sensor footprint might explain the low inertias. We find that the bedrock component of the surface can have a thermal inertia as high as 650-1700 J m(exp. -2) K(exp. -1) s(exp. -1/2) for mudstone sites and approx. 700 J m(exp. -2) K(exp. -1) s(exp. - 1/2) for sandstone sites in models runs that include lateral and vertical mixing. Although the results of our forward modeling approach may be non-unique, they demonstrate the potential to extract information about lateral and vertical variations in thermophysical properties from temporally resolved measurements of ground temperature.

  13. Reconstruction of Sky Illumination Domes from Ground-Based Panoramas

    Science.gov (United States)

    Coubard, F.; Lelégard, L.; Brédif, M.; Paparoditis, N.; Briottet, X.

    2012-07-01

    The knowledge of the sky illumination is important for radiometric corrections and for computer graphics applications such as relighting or augmented reality. We propose an approach to compute environment maps, representing the sky radiance, from a set of ground-based images acquired by a panoramic acquisition system, for instance a mobile-mapping system. These images can be affected by important radiometric artifacts, such as bloom or overexposure. A Perez radiance model is estimated with the blue sky pixels of the images, and used to compute additive corrections in order to reduce these radiometric artifacts. The sky pixels are then aggregated in an environment map, which still suffers from discontinuities on stitching edges. The influence of the quality of estimated sky radiance on the simulated light signal is measured quantitatively on a simple synthetic urban scene; in our case, the maximal error for the total sensor radiance is about 10%.

  14. Optical Fiber Sensors Based on Nanoparticle-Embedded Coatings

    Directory of Open Access Journals (Sweden)

    Aitor Urrutia

    2015-01-01

    Full Text Available The use of nanoparticles (NPs in scientific applications has attracted the attention of many researchers in the last few years. The use of NPs can help researchers to tune the physical characteristics of the sensing coating (thickness, roughness, specific area, refractive index, etc. leading to enhanced sensors with response time or sensitivity better than traditional sensing coatings. Additionally, NPs also offer other special properties that depend on their nanometric size, and this is also a source of new sensing applications. This review focuses on the current status of research in the use of NPs within coatings in optical fiber sensing. Most used sensing principles in fiber optics are briefly described and classified into several groups: absorbance-based sensors, interferometric sensors, fluorescence-based sensors, fiber grating sensors, and resonance-based sensors, among others. For each sensor group, specific examples of the utilization of NP-embedded coatings in their sensing structure are reported.

  15. Evaluation of a HDR image sensor with logarithmic response for mobile video-based applications

    Science.gov (United States)

    Tektonidis, Marco; Pietrzak, Mateusz; Monnin, David

    2017-10-01

    The performance of mobile video-based applications using conventional LDR (Low Dynamic Range) image sensors highly depends on the illumination conditions. As an alternative, HDR (High Dynamic Range) image sensors with logarithmic response are capable to acquire illumination-invariant HDR images in a single shot. We have implemented a complete image processing framework for a HDR sensor, including preprocessing methods (nonuniformity correction (NUC), cross-talk correction (CTC), and demosaicing) as well as tone mapping (TM). We have evaluated the HDR sensor for video-based applications w.r.t. the display of images and w.r.t. image analysis techniques. Regarding the display we have investigated the image intensity statistics over time, and regarding image analysis we assessed the number of feature correspondences between consecutive frames of temporal image sequences. For the evaluation we used HDR image data recorded from a vehicle on outdoor or combined outdoor/indoor itineraries, and we performed a comparison with corresponding conventional LDR image data.

  16. Design and evaluation of a telemonitoring concept based on NFC-enabled mobile phones and sensor devices.

    Science.gov (United States)

    Morak, Jürgen; Kumpusch, Hannes; Hayn, Dieter; Modre-Osprian, Robert; Schreier, Günter

    2012-01-01

    Utilization of information and communication technologies such as mobile phones and wireless sensor networks becomes more and more common in the field of telemonitoring for chronic diseases. Providing elderly people with a mobile-phone-based patient terminal requires a barrier-free design of the overall user interface including the setup of wireless communication links to sensor devices. To easily manage the connection between a mobile phone and wireless sensor devices, a concept based on the combination of Bluetooth and near-field communication technology has been developed. It allows us initiating communication between two devices just by bringing them close together for a few seconds without manually configuring the communication link. This concept has been piloted with a sensor device and evaluated in terms of usability and feasibility. Results indicate that this solution has the potential to simplify the handling of wireless sensor networks for people with limited technical skills.

  17. Identifying and tracking pedestrians based on sensor fusion and motion stability predictions.

    Science.gov (United States)

    Musleh, Basam; García, Fernando; Otamendi, Javier; Armingol, José Maria; de la Escalera, Arturo

    2010-01-01

    The lack of trustworthy sensors makes development of Advanced Driver Assistance System (ADAS) applications a tough task. It is necessary to develop intelligent systems by combining reliable sensors and real-time algorithms to send the proper, accurate messages to the drivers. In this article, an application to detect and predict the movement of pedestrians in order to prevent an imminent collision has been developed and tested under real conditions. The proposed application, first, accurately measures the position of obstacles using a two-sensor hybrid fusion approach: a stereo camera vision system and a laser scanner. Second, it correctly identifies pedestrians using intelligent algorithms based on polylines and pattern recognition related to leg positions (laser subsystem) and dense disparity maps and u-v disparity (vision subsystem). Third, it uses statistical validation gates and confidence regions to track the pedestrian within the detection zones of the sensors and predict their position in the upcoming frames. The intelligent sensor application has been experimentally tested with success while tracking pedestrians that cross and move in zigzag fashion in front of a vehicle.

  18. Identifying and Tracking Pedestrians Based on Sensor Fusion and Motion Stability Predictions

    Directory of Open Access Journals (Sweden)

    Arturo de la Escalera

    2010-08-01

    Full Text Available The lack of trustworthy sensors makes development of Advanced Driver Assistance System (ADAS applications a tough task. It is necessary to develop intelligent systems by combining reliable sensors and real-time algorithms to send the proper, accurate messages to the drivers. In this article, an application to detect and predict the movement of pedestrians in order to prevent an imminent collision has been developed and tested under real conditions. The proposed application, first, accurately measures the position of obstacles using a two-sensor hybrid fusion approach: a stereo camera vision system and a laser scanner. Second, it correctly identifies pedestrians using intelligent algorithms based on polylines and pattern recognition related to leg positions (laser subsystem and dense disparity maps and u-v disparity (vision subsystem. Third, it uses statistical validation gates and confidence regions to track the pedestrian within the detection zones of the sensors and predict their position in the upcoming frames. The intelligent sensor application has been experimentally tested with success while tracking pedestrians that cross and move in zigzag fashion in front of a vehicle.

  19. High performance flexible pH sensor based on carboxyl-functionalized and DEP aligned SWNTs

    International Nuclear Information System (INIS)

    Liu, Lu; Shao, Jinyou; Li, Xiangming; Zhao, Qiang; Nie, Bangbang; Xu, Chuan; Ding, Haitao

    2016-01-01

    Highlights: • The flexible chemiresistive pH sensor based on two-terminal microsensors eliminating the need for a reference electrode, is simple in structure and can be fabricated on a variety of substrates such as PET, PI and PVC. • SWNTs as an ideal one dimensional material are carboxyl-functionalized to make the pH sensor show high sensitivity and outstanding flexibility for practical applications. • DEP technique is used to manipulate and position SWNTs into appropriate locations and desired formations to improve the metal-nanotube interface and highly rapid detection of pH value, resulting in better overall device performance. • Mechanical bendability of the pH sensor, which arises from the combination of flexible PET substrates and SWNTs, offer a significant improvement for applications that are difficult or impossible to achieve with traditional sensors on rigid substrates. - Abstract: The detection and control of the pH is very important in many biomedical and chemical reaction processes. A miniaturized flexible pH sensor that is light weight, robust, and conformable is very important in many applications, such as multifunctional lab-on-a-chip systems or wearable biomedical devices. In this work, we demonstrate a flexible chemiresistive pH sensor based on dielectrophoresis (DEP) aligned carboxyl-functionalized single-walled carbon nanotubes (SWNTs). Decorated carboxyl groups can react with hydrogen (H"+) and hydroxide (OH"−) ions, enabling the sensor to be capable of sensing the pH. DEP is used to deposit well-organized and highly aligned SWNTs in desired locations, which improves the metal-nanotube interface and highly rapid detection of the pH, resulting in better overall device performance. When pH buffer solutions are dropped onto such SWNTs, the H"+ and OH"− ions caninteract with the carboxyl groups and affect the generation of holes and electrons in the SWNTs, leading to resistance variations in the SWNTs. The results shows that the

  20. High performance flexible pH sensor based on carboxyl-functionalized and DEP aligned SWNTs

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lu; Shao, Jinyou, E-mail: jyshao@mail.xjtu.edu.cn; Li, Xiangming; Zhao, Qiang; Nie, Bangbang; Xu, Chuan; Ding, Haitao

    2016-11-15

    Highlights: • The flexible chemiresistive pH sensor based on two-terminal microsensors eliminating the need for a reference electrode, is simple in structure and can be fabricated on a variety of substrates such as PET, PI and PVC. • SWNTs as an ideal one dimensional material are carboxyl-functionalized to make the pH sensor show high sensitivity and outstanding flexibility for practical applications. • DEP technique is used to manipulate and position SWNTs into appropriate locations and desired formations to improve the metal-nanotube interface and highly rapid detection of pH value, resulting in better overall device performance. • Mechanical bendability of the pH sensor, which arises from the combination of flexible PET substrates and SWNTs, offer a significant improvement for applications that are difficult or impossible to achieve with traditional sensors on rigid substrates. - Abstract: The detection and control of the pH is very important in many biomedical and chemical reaction processes. A miniaturized flexible pH sensor that is light weight, robust, and conformable is very important in many applications, such as multifunctional lab-on-a-chip systems or wearable biomedical devices. In this work, we demonstrate a flexible chemiresistive pH sensor based on dielectrophoresis (DEP) aligned carboxyl-functionalized single-walled carbon nanotubes (SWNTs). Decorated carboxyl groups can react with hydrogen (H{sup +}) and hydroxide (OH{sup −}) ions, enabling the sensor to be capable of sensing the pH. DEP is used to deposit well-organized and highly aligned SWNTs in desired locations, which improves the metal-nanotube interface and highly rapid detection of the pH, resulting in better overall device performance. When pH buffer solutions are dropped onto such SWNTs, the H{sup +} and OH{sup −} ions caninteract with the carboxyl groups and affect the generation of holes and electrons in the SWNTs, leading to resistance variations in the SWNTs. The results

  1. Microstrip Patch Sensor for Salinity Determination.

    Science.gov (United States)

    Lee, Kibae; Hassan, Arshad; Lee, Chong Hyun; Bae, Jinho

    2017-12-18

    In this paper, a compact microstrip feed inset patch sensor is proposed for measuring the salinities in seawater. The working principle of the proposed sensor depends on the fact that different salinities in liquid have different relative permittivities and cause different resonance frequencies. The proposed sensor can obtain better sensitivity to salinity changes than common sensors using conductivity change, since the relative permittivity change to salinity is 2.5 times more sensitive than the conductivity change. The patch and ground plane of the proposed sensor are fabricated by conductive copper spray coating on the masks made by 3D printer. The fabricated patch and the ground plane are bonded to a commercial silicon substrate and then attached to 5 mm-high chamber made by 3D printer so that it contains only 1 mL seawater. For easy fabrication and testing, the maximum resonance frequency was selected under 3 GHz and to cover salinities in real seawater, it was assumed that the salinity changes from 20 to 35 ppt. The sensor was designed by the finite element method-based ANSYS high-frequency structure simulator (HFSS), and it can detect the salinity with 0.01 ppt resolution. The designed sensor has a resonance frequency separation of 37.9 kHz and reflection coefficients under -20 dB at the resonant frequencies. The fabricated sensor showed better performance with average frequency separation of 48 kHz and maximum reflection coefficient of -35 dB. By comparing with the existing sensors, the proposed compact and low-cost sensor showed a better detection capability. Therefore, the proposed patch sensor can be utilized in radio frequency (RF) tunable sensors for salinity determination.

  2. Touch sensors based on planar liquid crystal-gated-organic field-effect transistors

    International Nuclear Information System (INIS)

    Seo, Jooyeok; Lee, Chulyeon; Han, Hyemi; Lee, Sooyong; Nam, Sungho; Kim, Youngkyoo; Kim, Hwajeong; Lee, Joon-Hyung; Park, Soo-Young; Kang, Inn-Kyu

    2014-01-01

    We report a tactile touch sensor based on a planar liquid crystal-gated-organic field-effect transistor (LC-g-OFET) structure. The LC-g-OFET touch sensors were fabricated by forming the 10 μm thick LC layer (4-cyano-4 ′ -pentylbiphenyl - 5CB) on top of the 50 nm thick channel layer (poly(3-hexylthiophene) - P3HT) that is coated on the in-plane aligned drain/source/gate electrodes (indium-tin oxide - ITO). As an external physical stimulation to examine the tactile touch performance, a weak nitrogen flow (83.3 μl/s) was employed to stimulate the LC layer of the touch device. The LC-g-OFET device exhibited p-type transistor characteristics with a hole mobility of 1.5 cm 2 /Vs, but no sensing current by the nitrogen flow touch was measured at sufficiently high drain (V D ) and gate (V G ) voltages. However, a clear sensing current signal was detected at lower voltages, which was quite sensitive to the combination of V D and V G . The best voltage combination was V D = −0.2 V and V G = −1 V for the highest ratio of signal currents to base currents (i.e., signal-to-noise ratio). The change in the LC alignment upon the nitrogen flow touch was assigned as the mechanism for the present LC-g-OFET touch sensors

  3. Synthesis of High-Frequency Ground Motion Using Information Extracted from Low-Frequency Ground Motion

    Science.gov (United States)

    Iwaki, A.; Fujiwara, H.

    2012-12-01

    Broadband ground motion computations of scenario earthquakes are often based on hybrid methods that are the combinations of deterministic approach in lower frequency band and stochastic approach in higher frequency band. Typical computation methods for low-frequency and high-frequency (LF and HF, respectively) ground motions are the numerical simulations, such as finite-difference and finite-element methods based on three-dimensional velocity structure model, and the stochastic Green's function method, respectively. In such hybrid methods, LF and HF wave fields are generated through two different methods that are completely independent of each other, and are combined at the matching frequency. However, LF and HF wave fields are essentially not independent as long as they are from the same event. In this study, we focus on the relation among acceleration envelopes at different frequency bands, and attempt to synthesize HF ground motion using the information extracted from LF ground motion, aiming to propose a new method for broad-band strong motion prediction. Our study area is Kanto area, Japan. We use the K-NET and KiK-net surface acceleration data and compute RMS envelope at four frequency bands: 0.5-1.0 Hz, 1.0-2.0 Hz, 2.0-4.0 Hz, .0-8.0 Hz, and 8.0-16.0 Hz. Taking the ratio of the envelopes of adjacent bands, we find that the envelope ratios have stable shapes at each site. The empirical envelope-ratio characteristics are combined with low-frequency envelope of the target earthquake to synthesize HF ground motion. We have applied the method to M5-class earthquakes and a M7 target earthquake that occurred in the vicinity of Kanto area, and successfully reproduced the observed HF ground motion of the target earthquake. The method can be applied to a broad band ground motion simulation for a scenario earthquake by combining numerically-computed low-frequency (~1 Hz) ground motion with the empirical envelope ratio characteristics to generate broadband ground motion

  4. Patient Posture Monitoring System Based on Flexible Sensors

    Directory of Open Access Journals (Sweden)

    Youngsu Cha

    2017-03-01

    Full Text Available Monitoring patients using vision cameras can cause privacy intrusion problems. In this paper, we propose a patient position monitoring system based on a patient cloth with unobtrusive sensors. We use flexible sensors based on polyvinylidene fluoride, which is a flexible piezoelectric material. Theflexiblesensorsareinsertedintopartsclosetothekneeandhipoftheloosepatientcloth. We measure electrical signals from the sensors caused by the piezoelectric effect when the knee and hip in the cloth are bent. The measured sensor outputs are transferred to a computer via Bluetooth. We use a custom-made program to detect the position of the patient through a rule-based algorithm and the sensor outputs. The detectable postures are based on six human motions in and around a bed. The proposed system can detect the patient positions with a success rate over 88 percent for three patients.

  5. Broadband image sensor array based on graphene-CMOS integration

    Science.gov (United States)

    Goossens, Stijn; Navickaite, Gabriele; Monasterio, Carles; Gupta, Shuchi; Piqueras, Juan José; Pérez, Raúl; Burwell, Gregory; Nikitskiy, Ivan; Lasanta, Tania; Galán, Teresa; Puma, Eric; Centeno, Alba; Pesquera, Amaia; Zurutuza, Amaia; Konstantatos, Gerasimos; Koppens, Frank

    2017-06-01

    Integrated circuits based on complementary metal-oxide-semiconductors (CMOS) are at the heart of the technological revolution of the past 40 years, enabling compact and low-cost microelectronic circuits and imaging systems. However, the diversification of this platform into applications other than microcircuits and visible-light cameras has been impeded by the difficulty to combine semiconductors other than silicon with CMOS. Here, we report the monolithic integration of a CMOS integrated circuit with graphene, operating as a high-mobility phototransistor. We demonstrate a high-resolution, broadband image sensor and operate it as a digital camera that is sensitive to ultraviolet, visible and infrared light (300-2,000 nm). The demonstrated graphene-CMOS integration is pivotal for incorporating 2D materials into the next-generation microelectronics, sensor arrays, low-power integrated photonics and CMOS imaging systems covering visible, infrared and terahertz frequencies.

  6. System-Level Modelling and Simulation of MEMS-Based Sensors

    DEFF Research Database (Denmark)

    Virk, Kashif M.; Madsen, Jan; Shafique, Mohammad

    2005-01-01

    The growing complexity of MEMS devices and their increased used in embedded systems (e.g., wireless integrated sensor networks) demands a disciplined aproach for MEMS design as well as the development of techniques for system-level modeling of these devices so that a seamless integration with the......The growing complexity of MEMS devices and their increased used in embedded systems (e.g., wireless integrated sensor networks) demands a disciplined aproach for MEMS design as well as the development of techniques for system-level modeling of these devices so that a seamless integration...... with the existing embedded system design methodologies is possible. In this paper, we present a MEMS design methodology that uses VHDL-AMS based system-level model of a MEMS device as a starting point and combines the top-down and bottom-up design approaches for design, verification, and optimization...

  7. A CMOS smart temperature and humidity sensor with combined readout.

    Science.gov (United States)

    Eder, Clemens; Valente, Virgilio; Donaldson, Nick; Demosthenous, Andreas

    2014-09-16

    A fully-integrated complementary metal-oxide semiconductor (CMOS) sensor for combined temperature and humidity measurements is presented. The main purpose of the device is to monitor the hermeticity of micro-packages for implanted integrated circuits and to ensure their safe operation by monitoring the operating temperature and humidity on-chip. The smart sensor has two modes of operation, in which either the temperature or humidity is converted into a digital code representing a frequency ratio between two oscillators. This ratio is determined by the ratios of the timing capacitances and bias currents in both oscillators. The reference oscillator is biased by a current whose temperature dependency is complementary to the proportional to absolute temperature (PTAT) current. For the temperature measurement, this results in an exceptional normalized sensitivity of about 0.77%/°C at the accepted expense of reduced linearity. The humidity sensor is a capacitor, whose value varies linearly with relative humidity (RH) with a normalized sensitivity of 0.055%/% RH. For comparison, two versions of the humidity sensor with an area of either 0.2 mm2 or 1.2 mm2 were fabricated in a commercial 0.18 μm CMOS process. The on-chip readout electronics operate from a 5 V power supply and consume a current of approximately 85 µA.

  8. A Review of Microfiber-Based Temperature Sensors

    Directory of Open Access Journals (Sweden)

    Wanvisa Talataisong

    2018-02-01

    Full Text Available Optical microfiber-based temperature sensors have been proposed for many applications in a variety of industrial uses, including biomedical, geological, automotive, and defense applications. This increasing demand for these micrometric devices is attributed to their large dynamic range, high sensitivity, fast-response, compactness and robustness. Additionally, they can perform in-situ measurements remotely and in harsh environments. This paper presents an overview of optical microfibers, with a focus on their applications in temperature sensing. This review broadly divides microfiber-based temperature sensors into two categories: resonant and non-resonant microfiber sensors. While the former includes microfiber loop, knot and coil resonators, the latter comprises sensors based on functionally coated/doped microfibers, microfiber couplers, optical gratings and interferometers. In the conclusions, a summary of reported performances is presented.

  9. Mobile and static sensors in a citizen-based observatory of water

    Science.gov (United States)

    Brauchli, Tristan; Weijs, Steven V.; Lehning, Michael; Huwald, Hendrik

    2014-05-01

    Understanding and forecasting water resources and components of the water cycle require spatially and temporally resolved observations of numerous water-related variables. Such observations are often obtained from wireless networks of automated weather stations. The "WeSenseIt" project develops a citizen- and community-based observatory of water to improve the water and risk management at the catchment scale and to support decision-making of stakeholders. It is implemented in three case studies addressing various questions related to flood, drought, water resource management, water quality and pollution. Citizens become potential observers and may transmit water-related measurements and information. Combining the use of recent technologies (wireless communication, internet, smartphone) with the development of innovative low cost sensors enables the implementation of heterogeneous observatories, which (a) empower citizens and (b) expand and complement traditional operational sensing networks. With the goal of increasing spatial coverage of observations and decreasing cost for sensors, this study presents the examples of measuring (a) flow velocity in streams using smartphones and (b) sensible heat flux using simple sensors at the nodes of wireless sensor networks.

  10. APTAMER-BASED SERRS SENSOR FOR THROMBIN DETECTION

    Energy Technology Data Exchange (ETDEWEB)

    Cho, H; Baker, B R; Wachsmann-Hogiu, S; Pagba, C V; Laurence, T A; Lane, S M; Lee, L P; Tok, J B

    2008-07-02

    We describe an aptamer-based Surface Enhanced Resonance Raman Scattering (SERRS) sensor with high sensitivity, specificity, and stability for the detection of a coagulation protein, human a-thrombin. The sensor achieves high sensitivity and a limit of detection of 100 pM by monitoring the SERRS signal change upon the single step of thrombin binding to immobilized thrombin binding aptamer. The selectivity of the sensor is demonstrated by the specific discrimination of thrombin from other protein analytes. The specific recognition and binding of thrombin by the thrombin binding aptamer is essential to the mechanism of the aptamer-based sensor, as shown through measurements using negative control oligonucleotides. In addition, the sensor can detect 1 nM thrombin in the presence of complex biofluids, such as 10% fetal calf serum, demonstrating that the immobilized, 5{prime}-capped, 3{prime}-capped aptamer is sufficiently robust for clinical diagnostic applications. Furthermore, the proposed sensor may be implemented for multiplexed detection using different aptamer-Raman probe complexes.

  11. High Resolution Flexible Tactile Sensors

    DEFF Research Database (Denmark)

    Drimus, Alin; Bilberg, Arne

    2011-01-01

    both spatial distribution of pressure and dynamic events such as contact, release of contact and slip. Data acquisition and object recognition applications are described and it is proposed that such a sensor could be used in robotic grippers to improve object recognition, manipulation of objects......This paper describes the development of a tactile sensor for robotics inspired by the human sense of touch. It consists of two parts: a static tactile array sensor based on piezoresistive rubber and a dynamic sensor based on piezoelectric PVDF film. The combination of these two layers addresses...

  12. Long-Term, Autonomous Measurement of Atmospheric Carbon Dioxide Using an Ormosil Nanocomposite-Based Optical Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Kisholoy Goswami

    2005-10-11

    The goal of this project is to construct a prototype carbon dioxide sensor that can be commercialized to offer a low-cost, autonomous instrument for long-term, unattended measurements. Currently, a cost-effective CO2 sensor system is not available that can perform cross-platform measurements (ground-based or airborne platforms such as balloon and unmanned aerial vehicle (UAV)) for understanding the carbon sequestration phenomenon. The CO2 sensor would support the research objectives of DOE-sponsored programs such as AmeriFlux and the North American Carbon Program (NACP). Global energy consumption is projected to rise 60% over the next 20 years and use of oil is projected to increase by approximately 40%. The combustion of coal, oil, and natural gas has increased carbon emissions globally from 1.6 billion tons in 1950 to 6.3 billion tons in 2000. This figure is expected to reach 10 billon tons by 2020. It is important to understand the fate of this excess CO2 in the global carbon cycle. The overall goal of the project is to develop an accurate and reliable optical sensor for monitoring carbon dioxide autonomously at least for one year at a point remote from the actual CO2 release site. In Phase I of this project, InnoSense LLC (ISL) demonstrated the feasibility of an ormosil-monolith based Autonomous Sensor for Atmospheric CO2 (ASAC) device. All of the Phase I objectives were successfully met.

  13. REAL-TIME MONITORING SYSTEM USING UNMANNED AERIAL VEHICLE INTEGRATED WITH SENSOR OBSERVATION SERVICE

    Directory of Open Access Journals (Sweden)

    A. Witayangkurn

    2012-09-01

    Full Text Available The Unmanned Aerial Vehicle (UAV is an emerging technology being adapted for a wide range of applications. Real-time monitoring is essential to enhance the effectiveness of UAV applications. Sensor networks are networks constructed from various sensor nodes. International standard such as OGC's SOS (Sensor Observation Service makes it possible to share sensor data with other systems as well as to provide accessibility to globally distributed users. In this paper, we propose a system combining UAV technology and sensor network technology to use an UAV as a mobile node of sensor network so that the sensor data from UAV is published and shared real-time. A UAV can extend the observation range of a sensor network to remote areas where it is usually difficult to access such as disaster area. We constructed a UAV system using remote-controlled helicopter and various sensors such as GPS, gyrocompass, laser range finder, Digital camera and Thermometer. Furthermore, we extended the Sensor Observation Service (SOS and Sensor Service Grid (SSG to support mobile sensor nodes. Then, we conducted experiments of flying the helicopter over an area of the interest. During the flight, the system measured environmental data using its sensors and captured images of the ground. The data was sent to a SOS node as the ground station via Wi-Fi which was published using SSG to give real- time access to globally distributed users.

  14. Polymer based amperometric hydrogen sensor

    International Nuclear Information System (INIS)

    Ramesh, C.; Periaswami, G.; Mathews, C.K.; Shankar, P.

    1993-01-01

    A polymer based amperometric hydrogen sensor has been developed for measuring hydrogen in argon. Polyvinyl alcohol-phosphoric acid serves as the solid electrolyte for proton conduction. The electrolyte is sandwiched between two palladium films. Short circuit current between the film at room temperature is measured and is found to be linearly dependant on hydrogen concentration in argon to which one side of the film is exposed. The other side is exposed to air. The response time of the sensor is found to be improved on application of a D.C. potential of 200 mV in series. The sensitivity of the sensor is in ppm range. This may be sufficient for monitoring cover gas hydrogen in FBTR. Work is underway to improve the long-term stability of the sensor. (author)

  15. Hydrogel-based sensor for CO2 measurements

    NARCIS (Netherlands)

    Herber, S.; Olthuis, Wouter; Bergveld, Piet; van den Berg, Albert

    2004-01-01

    A hydrogel-based sensor is presented for CO2 measurements. The sensor consists of a pressure sensor and porous silicon cover. A pH-sensitive hydrogel is confined between the two parts. Furthermore the porous cover contains a bicarbonate solution and a gaspermeable membrane. CO2 reacts with the

  16. Combining satellite-based fire observations and ground-based lightning detections to identify lightning fires across the conterminous USA

    Science.gov (United States)

    Bar-Massada, A.; Hawbaker, T.J.; Stewart, S.I.; Radeloff, V.C.

    2012-01-01

    Lightning fires are a common natural disturbance in North America, and account for the largest proportion of the area burned by wildfires each year. Yet, the spatiotemporal patterns of lightning fires in the conterminous US are not well understood due to limitations of existing fire databases. Our goal here was to develop and test an algorithm that combined MODIS fire detections with lightning detections from the National Lightning Detection Network to identify lightning fires across the conterminous US from 2000 to 2008. The algorithm searches for spatiotemporal conjunctions of MODIS fire clusters and NLDN detected lightning strikes, given a spatiotemporal lag between lightning strike and fire ignition. The algorithm revealed distinctive spatial patterns of lightning fires in the conterminous US While a sensitivity analysis revealed that the algorithm is highly sensitive to the two thresholds that are used to determine conjunction, the density of fires it detected was moderately correlated with ground based fire records. When only fires larger than 0.4 km2 were considered, correlations were higher and the root-mean-square error between datasets was less than five fires per 625 km2 for the entire study period. Our algorithm is thus suitable for detecting broad scale spatial patterns of lightning fire occurrence, and especially lightning fire hotspots, but has limited detection capability of smaller fires because these cannot be consistently detected by MODIS. These results may enhance our understanding of large scale patterns of lightning fire activity, and can be used to identify the broad scale factors controlling fire occurrence.

  17. Reviewing Automated Sensor-Based Visitor Tracking Studies

    DEFF Research Database (Denmark)

    Mygind, Lærke; Bentsen, Peter

    2017-01-01

    The method of timing and tracking has a long history within visitor studies and exhibition evaluation. With an increase in indoor tracking research, sensor-based positioning tool usage in museums has grown, as have expectations regarding the efficacy of technological sensing systems. This literat......The method of timing and tracking has a long history within visitor studies and exhibition evaluation. With an increase in indoor tracking research, sensor-based positioning tool usage in museums has grown, as have expectations regarding the efficacy of technological sensing systems...... methods in terms of obtained level of detail, accuracy, level of obtrusiveness, automation of data entry, ability to time concurrent behaviors, and amount of observer training needed. Although individual sensor-based and traditional, observational methods had both strengths and weaknesses, all sensor......-based timing and tracking methods provided automated data entry and the opportunity to track a number of visitors simultaneously regardless of the available personnel....

  18. Cross-validation Methodology between Ground and GPM Satellite-based Radar Rainfall Product over Dallas-Fort Worth (DFW) Metroplex

    Science.gov (United States)

    Chen, H.; Chandrasekar, V.; Biswas, S.

    2015-12-01

    Over the past two decades, a large number of rainfall products have been developed based on satellite, radar, and/or rain gauge observations. However, to produce optimal rainfall estimation for a given region is still challenging due to the space time variability of rainfall at many scales and the spatial and temporal sampling difference of different rainfall instruments. In order to produce high-resolution rainfall products for urban flash flood applications and improve the weather sensing capability in urban environment, the center for Collaborative Adaptive Sensing of the Atmosphere (CASA), in collaboration with National Weather Service (NWS) and North Central Texas Council of Governments (NCTCOG), has developed an urban radar remote sensing network in DFW Metroplex. DFW is the largest inland metropolitan area in the U.S., that experiences a wide range of natural weather hazards such as flash flood and hailstorms. The DFW urban remote sensing network, centered by the deployment of eight dual-polarization X-band radars and a NWS WSR-88DP radar, is expected to provide impacts-based warning and forecasts for benefit of the public safety and economy. High-resolution quantitative precipitation estimation (QPE) is one of the major goals of the development of this urban test bed. In addition to ground radar-based rainfall estimation, satellite-based rainfall products for this area are also of interest for this study. Typical example is the rainfall rate product produced by the Dual-frequency Precipitation Radar (DPR) onboard Global Precipitation Measurement (GPM) Core Observatory satellite. Therefore, cross-comparison between ground and space-based rainfall estimation is critical to building an optimal regional rainfall system, which can take advantages of the sampling differences of different sensors. This paper presents the real-time high-resolution QPE system developed for DFW urban radar network, which is based upon the combination of S-band WSR-88DP and X

  19. Enhancing performances of a resistivity-type hydrogen sensor based on Pd/SnO2/RGO nanocomposites.

    Science.gov (United States)

    Peng, Yitian; Zheng, Lulu; Zou, Kun; Li, Cong

    2017-05-26

    Palladium/tin oxide/reduced graphene oxide (Pd/SnO 2 /RGO) nanocomposites with Pd and SnO 2 crystalline nanoparticles of high density and uniformity coated on RGO have been synthesized by a two-step reduction process. A novel hydrogen (H 2 ) sensor based on Pd/SnO 2 /RGO nanocomposites was fabricated by placing Pd/SnO 2 /RGO nanocomposites onto a pair of gold electrodes. The Pd/SnO 2 /RGO nanocomposite-based sensor exhibited higher responses than Pd/RGO to H 2 because the introduction of SnO 2 nanoparticles enhances H 2 adsorption and forms a P-N junction with RGO. The sensor shows a high response of 55% to 10 000 ppm H 2 , and a low detection limit, fast response, good selectivity and repeatability due to a combination effect of the Pd and SnO 2 nanoparticles. The studies provide a novel strategy for great potential applications of graphene-based gas sensors.

  20. GPM Ground Validation: Pre to Post-Launch Era

    Science.gov (United States)

    Petersen, Walt; Skofronick-Jackson, Gail; Huffman, George

    2015-04-01

    NASA GPM Ground Validation (GV) activities have transitioned from the pre to post-launch era. Prior to launch direct validation networks and associated partner institutions were identified world-wide, covering a plethora of precipitation regimes. In the U.S. direct GV efforts focused on use of new operational products such as the NOAA Multi-Radar Multi-Sensor suite (MRMS) for TRMM validation and GPM radiometer algorithm database development. In the post-launch, MRMS products including precipitation rate, accumulation, types and data quality are being routinely generated to facilitate statistical GV of instantaneous (e.g., Level II orbit) and merged (e.g., IMERG) GPM products. Toward assessing precipitation column impacts on product uncertainties, range-gate to pixel-level validation of both Dual-Frequency Precipitation Radar (DPR) and GPM microwave imager data are performed using GPM Validation Network (VN) ground radar and satellite data processing software. VN software ingests quality-controlled volumetric radar datasets and geo-matches those data to coincident DPR and radiometer level-II data. When combined MRMS and VN datasets enable more comprehensive interpretation of both ground and satellite-based estimation uncertainties. To support physical validation efforts eight (one) field campaigns have been conducted in the pre (post) launch era. The campaigns span regimes from northern latitude cold-season snow to warm tropical rain. Most recently the Integrated Precipitation and Hydrology Experiment (IPHEx) took place in the mountains of North Carolina and involved combined airborne and ground-based measurements of orographic precipitation and hydrologic processes underneath the GPM Core satellite. One more U.S. GV field campaign (OLYMPEX) is planned for late 2015 and will address cold-season precipitation estimation, process and hydrology in the orographic and oceanic domains of western Washington State. Finally, continuous direct and physical validation

  1. A carbon nanotube-based pressure sensor

    International Nuclear Information System (INIS)

    Karimov, Kh S; Saleem, M; Khan, Adam; Qasuria, T A; Mateen, A; Karieva, Z M

    2011-01-01

    In this study, a carbon nanotube (CNT)-based Al/CNT/Al pressure sensor was designed, fabricated and investigated. The sensor was fabricated by depositing CNTs on an adhesive elastic polymer tape and placing this in an elastic casing. The diameter of multiwalled nanotubes varied between 10 and 30 nm. The nominal thickness of the CNT layers in the sensors was in the range ∼300-430 μm. The inter-electrode distance (length) and the width of the surface-type sensors were in the ranges 4-6 and 3-4 mm, respectively. The dc resistance of the sensors decreased 3-4 times as the pressure was increased up to 17 kN m -2 . The resistance-pressure relationships were simulated.

  2. Retrieval of tropospheric HCHO in El Salvador using ground based DOAS

    Science.gov (United States)

    Abarca, W.; Gamez, K.; Rudamas, C.

    2017-12-01

    Formaldehyde (HCHO) is the most abundant carbonyl in the atmosphere, being an intermediate product in the oxidation of most volatile organic compounds (VOCs). HCHO is carcinogenic, and highly water soluble [1]. HCHO can originate from biomass burning and fossil fuel combustion and has been observed from satellite and ground-based sensors by using the Differential Optical Absorption Spectroscopy (DOAS) technique [2].DOAS products can be used for air quality monitoring, validation of chemical transport models, validation of satellite tropospheric column density retrievals, among others [3]. In this study, we report on column density levels of HCHO measured by ground based Multi-Axis -DOAS in different locations of El Salvador in March, 2015. We have not observed large differences of the HCHO column density values at different viewing directions. This result points out a reasonably polluted and hazy atmosphere in the measuring sites, as reported by other authors [4]. Average values ranging from 1016 to 1017 molecules / cm2 has been obtained. The contribution of vehicular traffic and biomass burning to the column density levels in these sites of El Salvador will be discussed. [1] A. R. Garcia et al., Atmos. Chem. Phys. 6, 4545 (2006) [2] E. Peters et al., Atmos. Chem. Phys. 12, 11179 (2012) [3] T. Vlemmix, et al. Atmos. Meas. Tech., 8, 941-963, 2015 [4] A. Heckel et al., Atmos. Chem. Phys. 5, (2005)

  3. RECONSTRUCTION OF SKY ILLUMINATION DOMES FROM GROUND-BASED PANORAMAS

    Directory of Open Access Journals (Sweden)

    F. Coubard

    2012-07-01

    Full Text Available The knowledge of the sky illumination is important for radiometric corrections and for computer graphics applications such as relighting or augmented reality. We propose an approach to compute environment maps, representing the sky radiance, from a set of ground-based images acquired by a panoramic acquisition system, for instance a mobile-mapping system. These images can be affected by important radiometric artifacts, such as bloom or overexposure. A Perez radiance model is estimated with the blue sky pixels of the images, and used to compute additive corrections in order to reduce these radiometric artifacts. The sky pixels are then aggregated in an environment map, which still suffers from discontinuities on stitching edges. The influence of the quality of estimated sky radiance on the simulated light signal is measured quantitatively on a simple synthetic urban scene; in our case, the maximal error for the total sensor radiance is about 10%.

  4. MetaSensing's FastGBSAR: ground based radar for deformation monitoring

    Science.gov (United States)

    Rödelsperger, Sabine; Meta, Adriano

    2014-10-01

    The continuous monitoring of ground deformation and structural movement has become an important task in engineering. MetaSensing introduces a novel sensor system, the Fast Ground Based Synthetic Aperture Radar (FastGBSAR), based on innovative technologies that have already been successfully applied to airborne SAR applications. The FastGBSAR allows the remote sensing of deformations of a slope or infrastructure from up to a distance of 4 km. The FastGBSAR can be setup in two different configurations: in Real Aperture Radar (RAR) mode it is capable of accurately measuring displacements along a linear range profile, ideal for monitoring vibrations of structures like bridges and towers (displacement accuracy up to 0.01 mm). Modal parameters can be determined within half an hour. Alternatively, in Synthetic Aperture Radar (SAR) configuration it produces two-dimensional displacement images with an acquisition time of less than 5 seconds, ideal for monitoring areal structures like dams, landslides and open pit mines (displacement accuracy up to 0.1 mm). The MetaSensing FastGBSAR is the first ground based SAR instrument on the market able to produce two-dimensional deformation maps with this high acquisition rate. By that, deformation time series with a high temporal and spatial resolution can be generated, giving detailed information useful to determine the deformation mechanisms involved and eventually to predict an incoming failure. The system is fully portable and can be quickly installed on bedrock or a basement. The data acquisition and processing can be fully automated leading to a low effort in instrument operation and maintenance. Due to the short acquisition time of FastGBSAR, the coherence between two acquisitions is very high and the phase unwrapping is simplified enormously. This yields a high density of resolution cells with good quality and high reliability of the acquired deformations. The deformation maps can directly be used as input into an Early

  5. Inertial Sensor-Based Gait Recognition: A Review

    Science.gov (United States)

    Sprager, Sebastijan; Juric, Matjaz B.

    2015-01-01

    With the recent development of microelectromechanical systems (MEMS), inertial sensors have become widely used in the research of wearable gait analysis due to several factors, such as being easy-to-use and low-cost. Considering the fact that each individual has a unique way of walking, inertial sensors can be applied to the problem of gait recognition where assessed gait can be interpreted as a biometric trait. Thus, inertial sensor-based gait recognition has a great potential to play an important role in many security-related applications. Since inertial sensors are included in smart devices that are nowadays present at every step, inertial sensor-based gait recognition has become very attractive and emerging field of research that has provided many interesting discoveries recently. This paper provides a thorough and systematic review of current state-of-the-art in this field of research. Review procedure has revealed that the latest advanced inertial sensor-based gait recognition approaches are able to sufficiently recognise the users when relying on inertial data obtained during gait by single commercially available smart device in controlled circumstances, including fixed placement and small variations in gait. Furthermore, these approaches have also revealed considerable breakthrough by realistic use in uncontrolled circumstances, showing great potential for their further development and wide applicability. PMID:26340634

  6. Organic Thin-Film Transistor (OTFT-Based Sensors

    Directory of Open Access Journals (Sweden)

    Daniel Elkington

    2014-04-01

    Full Text Available Organic thin film transistors have been a popular research topic in recent decades and have found applications from flexible displays to disposable sensors. In this review, we present an overview of some notable articles reporting sensing applications for organic transistors with a focus on the most recent publications. In particular, we concentrate on three main types of organic transistor-based sensors: biosensors, pressure sensors and “e-nose”/vapour sensors.

  7. Wireless interrogation of passive antenna sensors

    International Nuclear Information System (INIS)

    Deshmukh, S; Huang, H

    2010-01-01

    Recently, we discovered that the resonant frequency of a microstrip patch antenna is sensitive to mechanical strains or crack presence in the ground plane. Based on this principle, antenna sensors have been demonstrated to measure strain and detect crack in metallic structures. This paper presents a wireless method to remotely interrogate a dual-frequency antenna sensor. An interrogation horn antenna was used to irradiate the antenna sensor with a linear chirp microwave signal. By implementing a light-activated switch at the sensor node and performing signal processing of the backscattered signals, the resonant frequencies of the antenna sensor along both polarizations can be measured remotely. Since the antenna sensor does not need a local power source and can be interrogated wirelessly, electric wiring can be eliminated. The sensor implementation, the signal processing and the experimental setup that validate the remote interrogation of the antenna sensor are presented. A power budget model has also been established to estimate the maximum interrogation range

  8. Electrochemical sensors and biosensors based on redox polymer/carbon nanotube modified electrodes: a review.

    Science.gov (United States)

    Barsan, Madalina M; Ghica, M Emilia; Brett, Christopher M A

    2015-06-30

    The aim of this review is to present the contributions to the development of electrochemical sensors and biosensors based on polyphenazine or polytriphenylmethane redox polymers together with carbon nanotubes (CNT) during recent years. Phenazine polymers have been widely used in analytical applications due to their inherent charge transport properties and electrocatalytic effects. At the same time, since the first report on a CNT-based sensor, their application in the electroanalytical chemistry field has demonstrated that the unique structure and properties of CNT are ideal for the design of electrochemical (bio)sensors. We describe here that the specific combination of phenazine/triphenylmethane polymers with CNT leads to an improved performance of the resulting sensing devices, because of their complementary electrical, electrochemical and mechanical properties, and also due to synergistic effects. The preparation of polymer/CNT modified electrodes will be presented together with their electrochemical and surface characterization, with emphasis on the contribution of each component on the overall properties of the modified electrodes. Their importance in analytical chemistry is demonstrated by the numerous applications based on polymer/CNT-driven electrocatalytic effects, and their analytical performance as (bio) sensors is discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Real-Time Monitoring System Using Smartphone-Based Sensors and NoSQL Database for Perishable Supply Chain

    Directory of Open Access Journals (Sweden)

    Ganjar Alfian

    2017-11-01

    Full Text Available Since customer attention is increasing due to growing customer health awareness, it is important for the perishable food supply chain to monitor food quality and safety. This study proposes a real-time monitoring system that utilizes smartphone-based sensors and a big data platform. Firstly, we develop a smartphone-based sensor to gather temperature, humidity, GPS, and image data. The IoT-generated sensor on the smartphone has characteristics such as a large amount of storage, an unstructured format, and continuous data generation. Thus, in this study, we propose an effective big data platform design to handle IoT-generated sensor data. Furthermore, the abnormal sensor data generated by failed sensors is called outliers and may arise in real cases. The proposed system utilizes outlier detection based on statistical and clustering approaches to filter out the outlier data. The proposed system was evaluated for system and gateway performance and tested on the kimchi supply chain in Korea. The results showed that the proposed system is capable of processing a massive input/output of sensor data efficiently when the number of sensors and clients increases. The current commercial smartphones are sufficiently capable of combining their normal operations with simultaneous performance as gateways for transmitting sensor data to the server. In addition, the outlier detection based on the 3-sigma and DBSCAN were used to successfully detect/classify outlier data as separate from normal sensor data. This study is expected to help those who are responsible for developing the real-time monitoring system and implementing critical strategies related to the perishable supply chain.

  10. Response mechanism for surface acoustic wave gas sensors based on surface-adsorption.

    Science.gov (United States)

    Liu, Jiansheng; Lu, Yanyan

    2014-04-16

    A theoretical model is established to describe the response mechanism of surface acoustic wave (SAW) gas sensors based on physical adsorption on the detector surface. Wohljent's method is utilized to describe the relationship of sensor output (frequency shift of SAW oscillator) and the mass loaded on the detector surface. The Brunauer-Emmett-Teller (BET) formula and its improved form are introduced to depict the adsorption behavior of gas on the detector surface. By combining the two methods, we obtain a theoretical model for the response mechanism of SAW gas sensors. By using a commercial SAW gas chromatography (GC) analyzer, an experiment is performed to measure the frequency shifts caused by different concentration of dimethyl methylphosphonate (DMMP). The parameters in the model are given by fitting the experimental results and the theoretical curve agrees well with the experimental data.

  11. FPGA-based multimodal embedded sensor system integrating low- and mid-level vision.

    Science.gov (United States)

    Botella, Guillermo; Martín H, José Antonio; Santos, Matilde; Meyer-Baese, Uwe

    2011-01-01

    Motion estimation is a low-level vision task that is especially relevant due to its wide range of applications in the real world. Many of the best motion estimation algorithms include some of the features that are found in mammalians, which would demand huge computational resources and therefore are not usually available in real-time. In this paper we present a novel bioinspired sensor based on the synergy between optical flow and orthogonal variant moments. The bioinspired sensor has been designed for Very Large Scale Integration (VLSI) using properties of the mammalian cortical motion pathway. This sensor combines low-level primitives (optical flow and image moments) in order to produce a mid-level vision abstraction layer. The results are described trough experiments showing the validity of the proposed system and an analysis of the computational resources and performance of the applied algorithms.

  12. Microstrip Patch Sensor for Salinity Determination

    Directory of Open Access Journals (Sweden)

    Kibae Lee

    2017-12-01

    Full Text Available In this paper, a compact microstrip feed inset patch sensor is proposed for measuring the salinities in seawater. The working principle of the proposed sensor depends on the fact that different salinities in liquid have different relative permittivities and cause different resonance frequencies. The proposed sensor can obtain better sensitivity to salinity changes than common sensors using conductivity change, since the relative permittivity change to salinity is 2.5 times more sensitive than the conductivity change. The patch and ground plane of the proposed sensor are fabricated by conductive copper spray coating on the masks made by 3D printer. The fabricated patch and the ground plane are bonded to a commercial silicon substrate and then attached to 5 mm-high chamber made by 3D printer so that it contains only 1 mL seawater. For easy fabrication and testing, the maximum resonance frequency was selected under 3 GHz and to cover salinities in real seawater, it was assumed that the salinity changes from 20 to 35 ppt. The sensor was designed by the finite element method-based ANSYS high-frequency structure simulator (HFSS, and it can detect the salinity with 0.01 ppt resolution. The designed sensor has a resonance frequency separation of 37.9 kHz and reflection coefficients under −20 dB at the resonant frequencies. The fabricated sensor showed better performance with average frequency separation of 48 kHz and maximum reflection coefficient of −35 dB. By comparing with the existing sensors, the proposed compact and low-cost sensor showed a better detection capability. Therefore, the proposed patch sensor can be utilized in radio frequency (RF tunable sensors for salinity determination.

  13. Hybrid active pixel sensors in infrared astronomy

    International Nuclear Information System (INIS)

    Finger, Gert; Dorn, Reinhold J.; Meyer, Manfred; Mehrgan, Leander; Stegmeier, Joerg; Moorwood, Alan

    2005-01-01

    Infrared astronomy is currently benefiting from three main technologies providing high-performance hybrid active pixel sensors. In the near infrared from 1 to 5 μm two technologies, both aiming for buttable 2Kx2K mosaics, are competing, namely InSb and HgCdTe grown by LPE or MBE on Al 2 O 3 , Si or CdZnTe substrates. Blocked impurity band Si:As arrays cover the mid infrared spectral range from 8 to 28 μm. Adaptive optics combined with multiple integral field units feeding high-resolution spectrographs drive the requirements for the array format of infrared sensors used at ground-based infrared observatories. The pixel performance is now approaching fundamental limits. In view of this development, a detection limit for the photon flux of the ideal detector will be derived, depending only on the temperature and the impedance of the detector. It will be shown that this limit is approximated by state of the art infrared arrays for long on-chip integrations. Different detector materials are compared and strategies to populate large focal planes are discussed. The need for the development of small-format low noise sensors for adaptive optics and interferometry will be pointed out

  14. A Protocol Layer Trust-Based Intrusion Detection Scheme for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Jian Wang

    2017-05-01

    Full Text Available This article proposes a protocol layer trust-based intrusion detection scheme for wireless sensor networks. Unlike existing work, the trust value of a sensor node is evaluated according to the deviations of key parameters at each protocol layer considering the attacks initiated at different protocol layers will inevitably have impacts on the parameters of the corresponding protocol layers. For simplicity, the paper mainly considers three aspects of trustworthiness, namely physical layer trust, media access control layer trust and network layer trust. The per-layer trust metrics are then combined to determine the overall trust metric of a sensor node. The performance of the proposed intrusion detection mechanism is then analyzed using the t-distribution to derive analytical results of false positive and false negative probabilities. Numerical analytical results, validated by simulation results, are presented in different attack scenarios. It is shown that the proposed protocol layer trust-based intrusion detection scheme outperforms a state-of-the-art scheme in terms of detection probability and false probability, demonstrating its usefulness for detecting cross-layer attacks.

  15. Chemical Sensors Based on Metal Oxide Nanostructures

    Science.gov (United States)

    Hunter, Gary W.; Xu, Jennifer C.; Evans, Laura J.; VanderWal, Randy L.; Berger, Gordon M.; Kulis, Mike J.; Liu, Chung-Chiun

    2006-01-01

    This paper is an overview of sensor development based on metal oxide nanostructures. While nanostructures such as nanorods show significan t potential as enabling materials for chemical sensors, a number of s ignificant technical challenges remain. The major issues addressed in this work revolve around the ability to make workable sensors. This paper discusses efforts to address three technical barriers related t o the application of nanostructures into sensor systems: 1) Improving contact of the nanostructured materials with electrodes in a microse nsor structure; 2) Controling nanostructure crystallinity to allow co ntrol of the detection mechanism; and 3) Widening the range of gases that can be detected by using different nanostructured materials. It is concluded that while this work demonstrates useful tools for furt her development, these are just the beginning steps towards realizati on of repeatable, controlled sensor systems using oxide based nanostr uctures.

  16. Wearable PPG sensor based alertness scoring system.

    Science.gov (United States)

    Dey, Jishnu; Bhowmik, Tanmoy; Sahoo, Saswata; Tiwari, Vijay Narayan

    2017-07-01

    Quantifying mental alertness in today's world is important as it enables the person to adopt lifestyle changes for better work efficiency. Miniaturized sensors in wearable devices have facilitated detection/monitoring of mental alertness. Photoplethysmography (PPG) sensors through Heart Rate Variability (HRV) offer one such opportunity by providing information about one's daily alertness levels without requiring any manual interference from the user. In this paper, a smartwatch based alertness estimation system is proposed. Data collected from PPG sensor of smartwatch is processed and fed to machine learning based model to get a continuous alertness score. Utility functions are designed based on statistical analysis to give a quality score on different stages of alertness such as awake, long sleep and short duration power nap. An intelligent data collection approach is proposed in collaboration with the motion sensor in the smartwatch to reduce battery drainage. Overall, our proposed wearable based system provides a detailed analysis of alertness over a period in a systematic and optimized manner. We were able to achieve an accuracy of 80.1% for sleep/awake classification along with alertness score. This opens up the possibility for quantifying alertness levels using a single PPG sensor for better management of health related activities including sleep.

  17. Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch.

    Science.gov (United States)

    Huang, Tao; Yan, Siyu; Yang, Fan; Pan, Tian; Liu, Jiang

    2016-01-19

    Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture.

  18. Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch

    Directory of Open Access Journals (Sweden)

    Tao Huang

    2016-01-01

    Full Text Available Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture.

  19. Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch

    Science.gov (United States)

    Huang, Tao; Yan, Siyu; Yang, Fan; Pan, Tian; Liu, Jiang

    2016-01-01

    Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture. PMID:26797616

  20. Planar Laser-Based QEPAS Trace Gas Sensor

    Directory of Open Access Journals (Sweden)

    Yufei Ma

    2016-06-01

    Full Text Available A novel quartz enhanced photoacoustic spectroscopy (QEPAS trace gas detection scheme is reported in this paper. A cylindrical lens was employed for near-infrared laser focusing. The laser beam was shaped as a planar line laser between the gap of the quartz tuning fork (QTF prongs. Compared with a spherical lens-based QEPAS sensor, the cylindrical lens-based QEPAS sensor has the advantages of easier laser beam alignment and a reduction of stringent stability requirements. Therefore, the reported approach is useful in long-term and continuous sensor operation.

  1. Cricket inspired flow-sensor arrays

    NARCIS (Netherlands)

    Krijnen, Gijsbertus J.M.; Lammerink, Theodorus S.J.; Wiegerink, Remco J.; Casas, J.

    2007-01-01

    We report current developments in biomimetic flow-sensors based on mechanoreceptive sensory hairs of crickets. These filiform hairs are highly perceptive to lowfrequency sound with energy sensitivities close to thermal threshold. In this work we describe hair-sensors fabricated by a combination of

  2. Diode laser based velocity sensors for industrial applications

    DEFF Research Database (Denmark)

    Iversen, Theis Faber Quist

    is part of a single optical unit, combining an additional optical spatial filter and a transmitter used for beam shaping. The optical unit used in the miniaturized sensor is acting in combination with an application specific integrated circuit (ASIC) fitted with appropriate detector arrays facilitating...... a two dimensional velocity measurement of in-plane translation of a rigid object (surface). Particularly, the beam shaping transmitter optic is redesigned for optimum performance using a Fourier optical diffraction model. Furthermore, a ray tracing model is developed for the receiving part...... and discussed. The observations made outlines possible advantageous properties that may be exploited to develop ultrathin touch sensitive sensors for use as cursor control devices in form-factor critical applications, such as e.g. mobile phones....

  3. Distributed data fusion across multiple hard and soft mobile sensor platforms

    Science.gov (United States)

    Sinsley, Gregory

    is a younger field than centralized fusion. The main issues in distributed fusion that are addressed are distributed classification and distributed tracking. There are several well established methods for performing distributed fusion that are first reviewed. The chapter on distributed fusion concludes with a multiple unmanned vehicle collaborative test involving an unmanned aerial vehicle and an unmanned ground vehicle. The third issue this thesis addresses is that of soft sensor only data fusion. Soft-only fusion is a newer field than centralized or distributed hard sensor fusion. Because of the novelty of the field, the chapter on soft only fusion contains less background information and instead focuses on some new results in soft sensor data fusion. Specifically, it discusses a novel fuzzy logic based soft sensor data fusion method. This new method is tested using both simulations and field measurements. The biggest issue addressed in this thesis is that of combined hard and soft fusion. Fusion of hard and soft data is the newest area for research in the data fusion community; therefore, some of the largest theoretical contributions in this thesis are in the chapter on combined hard and soft fusion. This chapter presents a novel combined hard and soft data fusion method based on random set theory, which processes random set data using a particle filter. Furthermore, the particle filter is designed to be distributed across multiple robots and portable computers (used by human observers) so that there is no centralized failure point in the system. After laying out a theoretical groundwork for hard and soft sensor data fusion the thesis presents practical applications for hard and soft sensor data fusion in simulation. Through a series of three progressively more difficult simulations, some important hard and soft sensor data fusion capabilities are demonstrated. The first simulation demonstrates fusing data from a single soft sensor and a single hard sensor in

  4. Two-Channel SPR Sensor Combined Application of Polymer- and Vitreous-Clad Optic Fibers

    Directory of Open Access Journals (Sweden)

    Yong Wei

    2017-12-01

    Full Text Available By combining a polymer-clad optic fiber and a vitreous-clad optic fiber, we proposed and fabricated a novel optic fiber surface plasmon resonance (SPR sensor to conduct two-channel sensing at the same detection area. The traditional optic fiber SPR sensor has many disadvantages; for example, removing the cladding requires corrosion, operating it is dangerous, adjusting the dynamic response range is hard, and producing different resonance wavelengths in the sensing area to realize a multi-channel measurement is difficult. Therefore, in this paper, we skillfully used bare fiber grinding technology and reverse symmetry welding technology to remove the cladding in a multi-mode fiber and expose the evanescent field. On the basis of investigating the effect of the grinding angle on the dynamic range change of the SPR resonance valley wavelength and sensitivity, we combined polymer-clad fiber and vitreous-clad fiber by a smart design structure to realize at a single point a two-channel measurement fiber SPR sensor. In this paper, we obtained a beautiful spectral curve from a multi-mode fiber two-channel SPR sensor. In the detection range of the refractive rate between 1.333 RIU and 1.385 RIU, the resonance valley wavelength of channel Ⅰ shifted from 622 nm to 724 nm with a mean average sensitivity of 1961 nm/RIU and the resonance valley wavelength of channel Ⅱ shifted from 741 nm to 976 nm with a mean average sensitivity of 4519 nm/RIU.

  5. Two-Channel SPR Sensor Combined Application of Polymer- and Vitreous-Clad Optic Fibers.

    Science.gov (United States)

    Wei, Yong; Su, Yudong; Liu, Chunlan; Nie, Xiangfei; Liu, Zhihai; Zhang, Yu; Zhang, Yonghui

    2017-12-09

    By combining a polymer-clad optic fiber and a vitreous-clad optic fiber, we proposed and fabricated a novel optic fiber surface plasmon resonance (SPR) sensor to conduct two-channel sensing at the same detection area. The traditional optic fiber SPR sensor has many disadvantages; for example, removing the cladding requires corrosion, operating it is dangerous, adjusting the dynamic response range is hard, and producing different resonance wavelengths in the sensing area to realize a multi-channel measurement is difficult. Therefore, in this paper, we skillfully used bare fiber grinding technology and reverse symmetry welding technology to remove the cladding in a multi-mode fiber and expose the evanescent field. On the basis of investigating the effect of the grinding angle on the dynamic range change of the SPR resonance valley wavelength and sensitivity, we combined polymer-clad fiber and vitreous-clad fiber by a smart design structure to realize at a single point a two-channel measurement fiber SPR sensor. In this paper, we obtained a beautiful spectral curve from a multi-mode fiber two-channel SPR sensor. In the detection range of the refractive rate between 1.333 RIU and 1.385 RIU, the resonance valley wavelength of channel Ⅰ shifted from 622 nm to 724 nm with a mean average sensitivity of 1961 nm/RIU and the resonance valley wavelength of channel Ⅱ shifted from 741 nm to 976 nm with a mean average sensitivity of 4519 nm/RIU.

  6. Integrated chemical sensor array platform based on a light emitting diode, xerogel-derived sensor elements, and high-speed pin printing

    International Nuclear Information System (INIS)

    Cho, Eun Jeong; Bright, Frank V.

    2002-01-01

    We report a new, solid-state, integrated optical array sensor platform. By using pin printing technology in concert with sol-gel-processing methods, we form discrete xerogel-based microsensor elements that are on the order of 100 μm in diameter and 1 μm thick directly on the face of a light emitting diode (LED). The LED serves as the light source to excite chemically responsive luminophores sequestered within the doped xerogel microsensors and the analyte-dependent emission from within the doped xerogel is detected with a charge coupled device (CCD). We overcome the problem of background illumination from the LED reaching the CCD and the associated biasing that results by coating the LED first with a thin layer of blue paint. The thin paint layer serves as an optical filter, knocking out the LEDs red-edge spectral tail. The problem of the spatially-dependent fluence across the LED face is solved entirely by performing ratiometric measurements. We illustrate the performance of the new sensor scheme by forming an array of 100 discrete O 2 -responsive sensing elements on the face of a single LED. The combination of pin printing with an integrated sensor and light source platform results in a rapid method of forming (∼1 s per sensor element) reusable sensor arrays. The entire sensor array can be calibrated using just one sensor element. Array-to-array reproducibly is <8%. Arrays can be formed using single or multiple pins with indistinguishable analytical performance

  7. A Review of Carbon Nanotubes-Based Gas Sensors

    Directory of Open Access Journals (Sweden)

    Yun Wang

    2009-01-01

    Full Text Available Gas sensors have attracted intensive research interest due to the demand of sensitive, fast response, and stable sensors for industry, environmental monitoring, biomedicine, and so forth. The development of nanotechnology has created huge potential to build highly sensitive, low cost, portable sensors with low power consumption. The extremely high surface-to-volume ratio and hollow structure of nanomaterials is ideal for the adsorption of gas molecules. Particularly, the advent of carbon nanotubes (CNTs has fuelled the inventions of gas sensors that exploit CNTs' unique geometry, morphology, and material properties. Upon exposure to certain gases, the changes in CNTs' properties can be detected by various methods. Therefore, CNTs-based gas sensors and their mechanisms have been widely studied recently. In this paper, a broad but yet in-depth survey of current CNTs-based gas sensing technology is presented. Both experimental works and theoretical simulations are reviewed. The design, fabrication, and the sensing mechanisms of the CNTs-based gas sensors are discussed. The challenges and perspectives of the research are also addressed in this review.

  8. An H₂S Sensor Based on Electrochemistry for Chicken Coops.

    Science.gov (United States)

    Zeng, Lihua; He, Mei; Yu, Huihui; Li, Daoliang

    2016-08-31

    The recent modernization of the livestock industry lags behind the scale of the livestock industry, particularly in indoor environmental monitoring. In particular, the H₂S gas concentration in chicken coops affects the growth and reproductive capacity of the chickens and threatens their health. Therefore, the research and development of a low-cost, environmentally friendly sensor that can achieve on-line monitoring of H₂S gas has a notably important practical significance. This paper reports the design of an H₂S gas sensor, with selection of an electrochemical probe with high accuracy and wide measurement range using the relatively mature technology of electrochemical sensors. Although the probe of the sensor is the main factor that affects the sensor accuracy, the probe must be combined with a specifically designed signal condition circuit that can overcome the lack of an electrode to satisfy the requirements for the interconnection and matching between the output signal and the test instrument. Because the output current of the electrochemical electrode is small and likely to be disturbed by noise, we designed signal-conditioning modules. Through the signal-conditioning circuit, the output signal of the current electrode can be converted into a voltage and amplified. In addition, we designed a power control module because a bias voltage is necessary for the electrode. Finally, after the calibration experiment, the accurate concentration of H₂S gas can be measured. Based on the experimental analysis, the sensor shows good linearity and selectivity, comparatively high sensitivity, perfect stability and an extremely long operating life of up to two years.

  9. Three-Axis Ground Reaction Force Distribution during Straight Walking.

    Science.gov (United States)

    Hori, Masataka; Nakai, Akihito; Shimoyama, Isao

    2017-10-24

    We measured the three-axis ground reaction force (GRF) distribution during straight walking. Small three-axis force sensors composed of rubber and sensor chips were fabricated and calibrated. After sensor calibration, 16 force sensors were attached to the left shoe. The three-axis force distribution during straight walking was measured, and the local features of the three-axis force under the sole of the shoe were analyzed. The heel area played a role in receiving the braking force, the base area of the fourth and fifth toes applied little vertical or shear force, the base area of the second and third toes generated a portion of the propulsive force and received a large vertical force, and the base area of the big toe helped move the body's center of mass to the other foot. The results demonstrate that measuring the three-axis GRF distribution is useful for a detailed analysis of bipedal locomotion.

  10. SU-8 Based Piezoresistive Mechanical Sensor

    DEFF Research Database (Denmark)

    Thaysen, Jacob; Yalcinkaya, Arda Deniz; Vestergaard, R.K.

    2002-01-01

    We present the first SU-8 based piezoresistive mechanical sensor. Conventionally, silicon has been used as a piezoresistive material due to its high gauge factor and thereby high sensitivity to strain changes in a sensor. By using the fact that SU-8 is much softer than silicon and that a gold...

  11. Fringe effect of electrical capacitance and resistance tomography sensors

    International Nuclear Information System (INIS)

    Sun, Jiangtao; Yang, Wuqiang

    2013-01-01

    Because of the ‘soft-field’ nature, all electrical tomography sensors suffer from electric field distortion, i.e. the fringe effect. In electrical resistance tomography (ERT) sensors, small pin electrodes are commonly used. It is well known that the pin electrodes result in severe electric field distortion or the fringe effect, and the sensing region of such an ERT sensor spreads out of the pin electrode plane to a large volume. This is also true for electrical capacitance tomography (ECT) sensors, even though it is less severe because of larger electrodes and grounded end guards used. However, when the length of electrodes in an ECT sensor without guards is reduced to almost the same dimension as those in an ERT sensor, the fringe effect is equally obvious. To investigate the fringe effect of ERT and ECT sensors with and without guards, simulations were carried out with different length of electrodes and the results are compared with the corresponding 2D simulation. It is concluded that ECT and ERT sensors with longer electrodes have less fringe effect. Because grounded end guards are effective in reducing the fringe effect of ECT sensors, we propose to apply grounded guards in ERT sensors and integrate ECT and ERT sensors together. Simulation results reveal that ERT sensors with grounded guards have less fringe effect. While commonly current excitation is used with ERT sensors, we propose voltage excitation instead to apply the grounded guards. The feasibility of this approach has been verified by experiment. Finally, a common structure for reducing the fringe effect is proposed for ECT and ERT sensors for the first time to simplify the sensor structure and reduce the mutual interference in ECT/ERT dual-modality measurements. (paper)

  12. Development of GaN-based microchemical sensor nodes

    Science.gov (United States)

    Prokopuk, Nicholas; Son, Kyung-Ah; George, Thomas; Moon, Jeong S.

    2005-01-01

    Sensors based III-N technology are gaining significant interest due to their potential for monolithic integration of RF transceivers and light sources and the capability of high temperature operations. We are developing a GaN-based micro chemical sensor node for remote detection of chemical toxins, and present electrical responses of AlGaN/GaN HEMT (High Electron Mobility Transistor) sensors to chemical toxins as well as other common gases.

  13. Optical Fiber Sensors Based on Fiber Ring Laser Demodulation Technology.

    Science.gov (United States)

    Xie, Wen-Ge; Zhang, Ya-Nan; Wang, Peng-Zhao; Wang, Jian-Zhang

    2018-02-08

    A review for optical fiber sensors based on fiber ring laser (FRL) demodulation technology is presented. The review focuses on the principles, main structures, and the sensing performances of different kinds of optical fiber sensors based on FRLs. First of all, the theory background of the sensors has been discussed. Secondly, four different types of sensors are described and compared, which includes Mach-Zehnder interferometer (MZI) typed sensors, Fabry-Perot interferometer (FPI) typed sensors, Sagnac typed sensors, and fiber Bragg grating (FBG) typed sensors. Typical studies and main properties of each type of sensors are presented. Thirdly, a comparison of different types of sensors are made. Finally, the existing problems and future research directions are pointed out and analyzed.

  14. Doppler lidar sensor for precision navigation in GPS-deprived environment

    Science.gov (United States)

    Amzajerdian, F.; Pierrottet, D. F.; Hines, G. D.; Petway, L. B.; Barnes, B. W.

    2013-05-01

    Landing mission concepts that are being developed for exploration of solar system bodies are increasingly ambitious in their implementations and objectives. Most of these missions require accurate position and velocity data during their descent phase in order to ensure safe, soft landing at the pre-designated sites. Data from the vehicle's Inertial Measurement Unit will not be sufficient due to significant drift error after extended travel time in space. Therefore, an onboard sensor is required to provide the necessary data for landing in the GPS-deprived environment of space. For this reason, NASA Langley Research Center has been developing an advanced Doppler lidar sensor capable of providing accurate and reliable data suitable for operation in the highly constrained environment of space. The Doppler lidar transmits three laser beams in different directions toward the ground. The signal from each beam provides the platform velocity and range to the ground along the laser line-of-sight (LOS). The six LOS measurements are then combined in order to determine the three components of the vehicle velocity vector, and to accurately measure altitude and attitude angles relative to the local ground. These measurements are used by an autonomous Guidance, Navigation, and Control system to accurately navigate the vehicle from a few kilometers above the ground to the designated location and to execute a gentle touchdown. A prototype version of our lidar sensor has been completed for a closed-loop demonstration onboard a rocket-powered terrestrial free-flyer vehicle.

  15. Synthesis, Characterization and Utility of Carbon Nanotube Based Hybrid Sensors in Bioanalytical Applications

    Science.gov (United States)

    Badhulika, Sushmee

    The detection of gaseous analytes and biological molecules is of prime importance in the fields of environmental pollution control, food and water - safety and analysis; and medical diagnostics. This necessitates the development of advanced and improved technology that is reliable, inexpensive and suitable for high volume production. The conventional sensors are often thin film based which lack sensitivity due to the phenomena of current shunting across the charge depleted region when an analyte binds with them. One dimensional (1-D) nanostructures provide a better alternative for sensing applications by eliminating the issue of current shunting due to their 1-D geometries and facilitating device miniaturization and low power operations. Carbon nanotubes (CNTs) are 1-D nanostructures that possess small size, high mechanical strength, high electrical and thermal conductivity and high specific area that have resulted in their wide spread applications in sensor technology. To overcome the issue of low sensitivity of pristine CNTs and to widen their scope, hybrid devices have been fabricated that combine the synergistic properties of CNTs along with materials like metals and conducting polymers (CPs). CPs exhibit electronic, magnetic and optical properties of metals and semiconductors while retaining the processing advantages of polymers. Their high chemical sensitivity, room temperature operation and tunable charge transport properties has made them ideal for use as transducing elements in chemical sensors. In this dissertation, various CNT based hybrid devices such as CNT-conducting polymer and graphene-CNT-metal nanoparticles based sensors have been developed and demonstrated towards bioanalytical applications such as detection of volatile organic compounds (VOCs) and saccharides. Electrochemical polymerization enabled the synthesis of CPs and metal nanoparticles in a simple, cost effective and controlled way on the surface of CNT based platforms thus resulting in

  16. An Ultrasensitive Organic Semiconductor NO2 Sensor Based on Crystalline TIPS-Pentacene Films.

    Science.gov (United States)

    Wang, Zi; Huang, Lizhen; Zhu, Xiaofei; Zhou, Xu; Chi, Lifeng

    2017-10-01

    Organic semiconductor gas sensor is one of the promising candidates of room temperature operated gas sensors with high selectivity. However, for a long time the performance of organic semiconductor sensors, especially for the detection of oxidizing gases, is far behind that of the traditional metal oxide gas sensors. Although intensive attempts have been made to address the problem, the performance and the understanding of the sensing mechanism are still far from sufficient. Herein, an ultrasensitive organic semiconductor NO 2 sensor based on 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-petacene) is reported. The device achieves a sensitivity over 1000%/ppm and fast response/recovery, together with a low limit of detection (LOD) of 20 ppb, all of which reach the level of metal oxide sensors. After a comprehensive analysis on the morphology and electrical properties of the organic films, it is revealed that the ultrahigh performance is largely related to the film charge transport ability, which was less concerned in the studies previously. And the combination of efficient charge transport and low original charge carrier concentration is demonstrated to be an effective access to obtain high performance organic semiconductor gas sensors. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Application for vibration monitoring of aspheric surface machining based on wireless sensor networks

    Science.gov (United States)

    Han, Chun Guang; Guo, Yin Biao; Jiang, Chen

    2010-05-01

    Any kinds of tiny vibration of machine tool parts will have a great influence on surface quality of the workpiece at ultra-precise machining process of aspheric surface. At present the major way for decreasing influence of vibration is machining compensation technology. Therefore it is important for machining compensation control to acquire and transmit these vibration signals effectively. This paper presents a vibration monitoring system of aspheric surface machining machine tool based on wireless sensor networks (WSN). Some key issues of wireless sensor networks for vibration monitoring system of aspheric surface machining are discussed. The reliability of data transmission, network communication protocol and synchronization mechanism of wireless sensor networks are studied for the vibration monitoring system. The proposed system achieves multi-sensors vibration monitoring involving the grinding wheel, the workpiece and the workbench spindle. The wireless transmission of vibration signals is achieved by the combination with vibration sensor nodes and wireless network. In this paper, these vibration sensor nodes are developed. An experimental platform is structured which employs wireless sensor networks to the vibration monitoring system in order to test acquisition and wireless transmission of vibration signal. The test results show that the proposed system can achieve vibration data transmission effectively and reliability and meet the monitoring requirements of aspheric surface machining machine tool.

  18. The lucky image-motion prediction for simple scene observation based soft-sensor technology

    Science.gov (United States)

    Li, Yan; Su, Yun; Hu, Bin

    2015-08-01

    High resolution is important to earth remote sensors, while the vibration of the platforms of the remote sensors is a major factor restricting high resolution imaging. The image-motion prediction and real-time compensation are key technologies to solve this problem. For the reason that the traditional autocorrelation image algorithm cannot meet the demand for the simple scene image stabilization, this paper proposes to utilize soft-sensor technology in image-motion prediction, and focus on the research of algorithm optimization in imaging image-motion prediction. Simulations results indicate that the improving lucky image-motion stabilization algorithm combining the Back Propagation Network (BP NN) and support vector machine (SVM) is the most suitable for the simple scene image stabilization. The relative error of the image-motion prediction based the soft-sensor technology is below 5%, the training computing speed of the mathematical predication model is as fast as the real-time image stabilization in aerial photography.

  19. Chemical Sensors Based on Cyclodextrin Derivatives.

    Science.gov (United States)

    Ogoshi, Tomoki; Harada, Akira

    2008-08-25

    This review focuses on chemical sensors based on cyclodextrin (CD) derivatives. This has been a field of classical interest, and is now of current interest for numerous scientists. First, typical chemical sensors using chromophore appended CDs are mentioned. Various "turn-off" and "turn-on" fluorescent chemical sensors, in which fluorescence intensity was decreased or increased by complexation with guest molecules, respectively, were synthesized. Dye modified CDs and photoactive metal ion-ligand complex appended CDs, metallocyclodextrins, were also applied for chemical sensors. Furthermore, recent novel approaches to chemical sensing systems using supramolecular structures such as CD dimers, trimers and cooperative binding systems of CDs with the other macrocycle [2]rotaxane and supramolecular polymers consisting of CD units are mentioned. New chemical sensors using hybrids of CDs with p-conjugated polymers, peptides, DNA, nanocarbons and nanoparticles are also described in this review.

  20. Combining satellite, aerial and ground measurements to assess forest carbon stocks in Democratic Republic of Congo

    Science.gov (United States)

    Beaumont, Benjamin; Bouvy, Alban; Stephenne, Nathalie; Mathoux, Pierre; Bastin, Jean-François; Baudot, Yves; Akkermans, Tom

    2015-04-01

    Monitoring tropical forest carbon stocks changes has been a rising topic in the recent years as a result of REDD+ mechanisms negotiations. Such monitoring will be mandatory for each project/country willing to benefit from these financial incentives in the future. Aerial and satellite remote sensing technologies offer cost advantages in implementing large scale forest inventories. Despite the recent progress made in the use of airborne LiDAR for carbon stocks estimation, no widely operational and cost effective method has yet been delivered for central Africa forest monitoring. Within the Maï Ndombe region of Democratic Republic of Congo, the EO4REDD project develops a method combining satellite, aerial and ground measurements. This combination is done in three steps: [1] mapping and quantifying forest cover changes using an object-based semi-automatic change detection (deforestation and forest degradation) methodology based on very high resolution satellite imagery (RapidEye), [2] developing an allometric linear model for above ground biomass measurements based on dendrometric parameters (tree crown areas and heights) extracted from airborne stereoscopic image pairs and calibrated using ground measurements of individual trees on a data set of 18 one hectare plots and [3] relating these two products to assess carbon stocks changes at a regional scale. Given the high accuracies obtained in [1] (> 80% for deforestation and 77% for forest degradation) and the suitable, but still to be improved with a larger calibrating sample, model (R² of 0.7) obtained in [2], EO4REDD products can be seen as a valid and replicable option for carbon stocks monitoring in tropical forests. Further improvements are planned to strengthen the cost effectiveness value and the REDD+ suitability in the second phase of EO4REDD. This second phase will include [A] specific model developments per forest type; [B] measurements of afforestation, reforestation and natural regeneration processes and

  1. Laser-based gas sensors keep moisture out of pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2006-07-15

    Natural gas often contains contaminants that cause corrosion, and long-term deterioration, and must be cleaned and brought to pipeline standards before it can be delivered to high-pressure, long-distance pipelines. Many older sensors produce false data that can result in contaminated gas getting through. This article presented details of the SpectraSensor, a new laser-based sensor technology used by the El Paso Natural Gas Company (EPNG). The SpectraSensor is comprised of a tunable diode laser (TDL) based technology developed by the National American Space Agency (NASA). The gas analyzer provides non-contact measurement of moisture, carbon dioxide, and other corrosives in natural gas pipelines, and the tunable laser-based gas sensors are fast, accurate, and flexible. Producers can monitor El Paso's gas analyzer readings by capturing the electronic signal from El Paso's unit via a SCADA system and view the readings from control rooms. While initial purchase price is higher than more problematic surface-based gas sensors, an evaluation of the technology has indicated that maintenance savings alone may provide an almost immediate return on investments. Unlike electrochemical and crystal gas sensors, laser-based gas analyzers do not come into direct contact with any substances, a fact which practically eliminates maintenance and operational costs. Studies have shown that the cost of operating conventional electrochemical sensors can result in a cumulative annual expense exceeding $50,000 per unit including labour; recalibration and rebuilding; back-up sensor heads; and gas dehydration and tariffs. 1 fig.

  2. Mechanisms of time-based figure-ground segregation.

    Science.gov (United States)

    Kandil, Farid I; Fahle, Manfred

    2003-11-01

    Figure-ground segregation can rely on purely temporal information, that is, on short temporal delays between positional changes of elements in figure and ground (Kandil, F.I. & Fahle, M. (2001) Eur. J. Neurosci., 13, 2004-2008). Here, we investigate the underlying mechanisms by measuring temporal segregation thresholds for various kinds of motion cues. Segregation can rely on monocular first-order motion (based on luminance modulation) and second-order motion cues (contrast modulation) with a high temporal resolution of approximately 20 ms. The mechanism can also use isoluminant motion with a reduced temporal resolution of 60 ms. Figure-ground segregation can be achieved even at presentation frequencies too high for human subjects to inspect successive frames individually. In contrast, when stimuli are presented dichoptically, i.e. separately to both eyes, subjects are unable to perceive any segregation, irrespective of temporal frequency. We propose that segregation in these displays is detected by a mechanism consisting of at least two stages. On the first level, standard motion or flicker detectors signal local positional changes (flips). On the second level, a segregation mechanism combines the local activities of the low-level detectors with high temporal precision. Our findings suggest that the segregation mechanism can rely on monocular detectors but not on binocular mechanisms. Moreover, the results oppose the idea that segregation in these displays is achieved by motion detectors of a higher order (motion-from-motion), but favour mechanisms sensitive to short temporal delays even without activation of higher-order motion detectors.

  3. Electrochemical DNA Hybridization Sensors Based on Conducting Polymers

    Science.gov (United States)

    Rahman, Md. Mahbubur; Li, Xiao-Bo; Lopa, Nasrin Siraj; Ahn, Sang Jung; Lee, Jae-Joon

    2015-01-01

    Conducting polymers (CPs) are a group of polymeric materials that have attracted considerable attention because of their unique electronic, chemical, and biochemical properties. This is reflected in their use in a wide range of potential applications, including light-emitting diodes, anti-static coating, electrochromic materials, solar cells, chemical sensors, biosensors, and drug-release systems. Electrochemical DNA sensors based on CPs can be used in numerous areas related to human health. This review summarizes the recent progress made in the development and use of CP-based electrochemical DNA hybridization sensors. We discuss the distinct properties of CPs with respect to their use in the immobilization of probe DNA on electrode surfaces, and we describe the immobilization techniques used for developing DNA hybridization sensors together with the various transduction methods employed. In the concluding part of this review, we present some of the challenges faced in the use of CP-based DNA hybridization sensors, as well as a future perspective. PMID:25664436

  4. Electrochemical DNA Hybridization Sensors Based on Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Md. Mahbubur Rahman

    2015-02-01

    Full Text Available Conducting polymers (CPs are a group of polymeric materials that have attracted considerable attention because of their unique electronic, chemical, and biochemical properties. This is reflected in their use in a wide range of potential applications, including light-emitting diodes, anti-static coating, electrochromic materials, solar cells, chemical sensors, biosensors, and drug-release systems. Electrochemical DNA sensors based on CPs can be used in numerous areas related to human health. This review summarizes the recent progress made in the development and use of CP-based electrochemical DNA hybridization sensors. We discuss the distinct properties of CPs with respect to their use in the immobilization of probe DNA on electrode surfaces, and we describe the immobilization techniques used for developing DNA hybridization sensors together with the various transduction methods employed. In the concluding part of this review, we present some of the challenges faced in the use of CP-based DNA hybridization sensors, as well as a future perspective.

  5. Graphene-Paper Based Electrochemical Sensors

    DEFF Research Database (Denmark)

    Zhang, Minwei; Halder, Arnab; Cao, Xianyi

    2017-01-01

    in electrochemical sensors and energy technologies amongothers. In this chapter, we present some examples to overview recent advances in theresearch and development of two-dimensional (2D) graphene papers as new materialsfor electrochemical sensors. The chapter covers the design, fabrication, functionalizationand...... functionalization ofgraphene papers with polymer and nanoscale functional building blocks for electrochemical-sensing purposes. In terms of electrochemical-sensing applications, the emphasis ison enzyme-graphene and nanoparticle-graphene paper-based systems for the detectionof glucose. We finally conclude...

  6. Quality assessment of the Ozone_cci Climate Research Data Package (release 2017) - Part 1: Ground-based validation of total ozone column data products

    Science.gov (United States)

    Garane, Katerina; Lerot, Christophe; Coldewey-Egbers, Melanie; Verhoelst, Tijl; Elissavet Koukouli, Maria; Zyrichidou, Irene; Balis, Dimitris S.; Danckaert, Thomas; Goutail, Florence; Granville, Jose; Hubert, Daan; Keppens, Arno; Lambert, Jean-Christopher; Loyola, Diego; Pommereau, Jean-Pierre; Van Roozendael, Michel; Zehner, Claus

    2018-03-01

    The GOME-type Total Ozone Essential Climate Variable (GTO-ECV) is a level-3 data record, which combines individual sensor products into one single cohesive record covering the 22-year period from 1995 to 2016, generated in the frame of the European Space Agency's Climate Change Initiative Phase II. It is based on level-2 total ozone data produced by the GODFIT (GOME-type Direct FITting) v4 algorithm as applied to the GOME/ERS-2, OMI/Aura, SCIAMACHY/Envisat and GOME-2/Metop-A and Metop-B observations. In this paper we examine whether GTO-ECV meets the specific requirements set by the international climate-chemistry modelling community for decadal stability long-term and short-term accuracy. In the following, we present the validation of the 2017 release of the Climate Research Data Package Total Ozone Column (CRDP TOC) at both level 2 and level 3. The inter-sensor consistency of the individual level-2 data sets has mean differences generally within 0.5 % at moderate latitudes (±50°), whereas the level-3 data sets show mean differences with respect to the OMI reference data record that span between -0.2 ± 0.9 % (for GOME-2B) and 1.0 ± 1.4 % (for SCIAMACHY). Very similar findings are reported for the level-2 validation against independent ground-based TOC observations reported by Brewer, Dobson and SAOZ instruments: the mean bias between GODFIT v4 satellite TOC and the ground instrument is well within 1.0 ± 1.0 % for all sensors, the drift per decade spans between -0.5 % and 1.0 ± 1.0 % depending on the sensor, and the peak-to-peak seasonality of the differences ranges from ˜ 1 % for GOME and OMI to ˜ 2 % for SCIAMACHY. For the level-3 validation, our first goal was to show that the level-3 CRDP produces findings consistent with the level-2 individual sensor comparisons. We show a very good agreement with 0.5 to 2 % peak-to-peak amplitude for the monthly mean difference time series and a negligible drift per decade of the differences in the Northern Hemisphere

  7. A New Acoustic Emission Sensor Based Gear Fault Detection Approach

    Directory of Open Access Journals (Sweden)

    Junda Zhu

    2013-01-01

    Full Text Available In order to reduce wind energy costs, prognostics and health management (PHM of wind turbine is needed to ensure the reliability and availability of wind turbines. A gearbox is an important component of a wind turbine. Therefore, developing effective gearbox fault detection tools is important to the PHM of wind turbine. In this paper, a new acoustic emission (AE sensor based gear fault detection approach is presented. This approach combines a heterodyne based frequency reduction technique with time synchronous average (TSA and spectrum kurtosis (SK to process AE sensor signals and extract features as condition indictors for gear fault detection. Heterodyne technique commonly used in communication is first employed to preprocess the AE signals before sampling. By heterodyning, the AE signal frequency is down shifted from several hundred kHz to below 50 kHz. This reduced AE signal sampling rate is comparable to that of vibration signals. The presented approach is validated using seeded gear tooth crack fault tests on a notational split torque gearbox. The approach presented in this paper is physics based and the validation results have showed that it could effectively detect the gear faults.

  8. General Data Acquisition Platform for Wireless Sensor Network Based on CC2538

    Directory of Open Access Journals (Sweden)

    Yang Zhi-Jun

    2017-01-01

    Full Text Available Wireless sensor networks are the hotspots of current research and have very wide application prospects. Its front end is a sensor that can sense and check the external world. This paper takes temperature and humidity as the research object, and builds a wireless sensor network data acquisition platform by combining the Internet of things and the WeChat public platform. The platform uses DHT11 temperature and humidity sensors and CC2538 sensor nodes to obtain the relevant data, through the server and database for data access. The combination with WeChat public platform not only allows us to view the temperature and humidity in the WeChat public, but also allows us to understand the environmental changes of the relevant detection area more conveniently and quickly. The effectiveness of the platform is also demonstrated by the collection of temperature and humidity data.

  9. Open architecture of smart sensor suites

    Science.gov (United States)

    Müller, Wilmuth; Kuwertz, Achim; Grönwall, Christina; Petersson, Henrik; Dekker, Rob; Reinert, Frank; Ditzel, Maarten

    2017-10-01

    Experiences from recent conflicts show the strong need for smart sensor suites comprising different multi-spectral imaging sensors as core elements as well as additional non-imaging sensors. Smart sensor suites should be part of a smart sensor network - a network of sensors, databases, evaluation stations and user terminals. Its goal is to optimize the use of various information sources for military operations such as situation assessment, intelligence, surveillance, reconnaissance, target recognition and tracking. Such a smart sensor network will enable commanders to achieve higher levels of situational awareness. Within the study at hand, an open system architecture was developed in order to increase the efficiency of sensor suites. The open system architecture for smart sensor suites, based on a system-of-systems approach, enables combining different sensors in multiple physical configurations, such as distributed sensors, co-located sensors combined in a single package, tower-mounted sensors, sensors integrated in a mobile platform, and trigger sensors. The architecture was derived from a set of system requirements and relevant scenarios. Its mode of operation is adaptable to a series of scenarios with respect to relevant objects of interest, activities to be observed, available transmission bandwidth, etc. The presented open architecture is designed in accordance with the NATO Architecture Framework (NAF). The architecture allows smart sensor suites to be part of a surveillance network, linked e.g. to a sensor planning system and a C4ISR center, and to be used in combination with future RPAS (Remotely Piloted Aircraft Systems) for supporting a more flexible dynamic configuration of RPAS payloads.

  10. Biological and chemical sensors based on graphene materials.

    Science.gov (United States)

    Liu, Yuxin; Dong, Xiaochen; Chen, Peng

    2012-03-21

    Owing to their extraordinary electrical, chemical, optical, mechanical and structural properties, graphene and its derivatives have stimulated exploding interests in their sensor applications ever since the first isolation of free-standing graphene sheets in year 2004. This article critically and comprehensively reviews the emerging graphene-based electrochemical sensors, electronic sensors, optical sensors, and nanopore sensors for biological or chemical detection. We emphasize on the underlying detection (or signal transduction) mechanisms, the unique roles and advantages of the used graphene materials. Properties and preparations of different graphene materials, their functionalizations are also comparatively discussed in view of sensor development. Finally, the perspective and current challenges of graphene sensors are outlined (312 references).

  11. Cooperative Opportunistic Pressure Based Routing for Underwater Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Nadeem Javaid

    2017-03-01

    Full Text Available In this paper, three opportunistic pressure based routing techniques for underwater wireless sensor networks (UWSNs are proposed. The first one is the cooperative opportunistic pressure based routing protocol (Co-Hydrocast, second technique is the improved Hydrocast (improved-Hydrocast, and third one is the cooperative improved Hydrocast (Co-improved Hydrocast. In order to minimize lengthy routing paths between the source and the destination and to avoid void holes at the sparse networks, sensor nodes are deployed at different strategic locations. The deployment of sensor nodes at strategic locations assure the maximum monitoring of the network field. To conserve the energy consumption and minimize the number of hops, greedy algorithm is used to transmit data packets from the source to the destination. Moreover, the opportunistic routing is also exploited to avoid void regions by making backward transmissions to find reliable path towards the destination in the network. The relay cooperation mechanism is used for reliable data packet delivery, when signal to noise ratio (SNR of the received signal is not within the predefined threshold then the maximal ratio combining (MRC is used as a diversity technique to improve the SNR of the received signals at the destination. Extensive simulations validate that our schemes perform better in terms of packet delivery ratio and energy consumption than the existing technique; Hydrocast.

  12. Cooperative Opportunistic Pressure Based Routing for Underwater Wireless Sensor Networks.

    Science.gov (United States)

    Javaid, Nadeem; Muhammad; Sher, Arshad; Abdul, Wadood; Niaz, Iftikhar Azim; Almogren, Ahmad; Alamri, Atif

    2017-03-19

    In this paper, three opportunistic pressure based routing techniques for underwater wireless sensor networks (UWSNs) are proposed. The first one is the cooperative opportunistic pressure based routing protocol (Co-Hydrocast), second technique is the improved Hydrocast (improved-Hydrocast), and third one is the cooperative improved Hydrocast (Co-improved Hydrocast). In order to minimize lengthy routing paths between the source and the destination and to avoid void holes at the sparse networks, sensor nodes are deployed at different strategic locations. The deployment of sensor nodes at strategic locations assure the maximum monitoring of the network field. To conserve the energy consumption and minimize the number of hops, greedy algorithm is used to transmit data packets from the source to the destination. Moreover, the opportunistic routing is also exploited to avoid void regions by making backward transmissions to find reliable path towards the destination in the network. The relay cooperation mechanism is used for reliable data packet delivery, when signal to noise ratio (SNR) of the received signal is not within the predefined threshold then the maximal ratio combining (MRC) is used as a diversity technique to improve the SNR of the received signals at the destination. Extensive simulations validate that our schemes perform better in terms of packet delivery ratio and energy consumption than the existing technique; Hydrocast.

  13. Characterization of cement-based materials using a reusable piezoelectric impedance-based sensor

    Science.gov (United States)

    Tawie, R.; Lee, H. K.

    2011-08-01

    This paper proposes a reusable sensor, which employs a piezoceramic (PZT) plate as an active sensing transducer, for non-destructive monitoring of cement-based materials based on the electromechanical impedance (EMI) sensing technique. The advantage of the sensor design is that the PZT can be easily removed from the set-up and re-used for repetitive tests. The applicability of the sensor was demonstrated for monitoring of the setting of cement mortar. EMI measurements were performed using an impedance analyzer and the transformation of the specimen from the plastic to solid state was monitored by automatically measuring the changes in the PZT conductance spectra with respect to curing time using the root mean square deviation (RMSD) algorithm. In another experiment, drying-induced moisture loss of a hardened mortar specimen at saturated surface dry (SSD) condition was measured, and monitored using the reusable sensor to establish a correlation between the RMSD values and moisture loss rate. The reusable sensor was also demonstrated for detecting progressive damages imparted on a mortar specimen attached with the sensor under several loading levels before allowing it to load to failure. Overall, the reusable sensor is an effective and efficient monitoring device that could possibly be used for field application in characterization of cement-based materials.

  14. Characterization of cement-based materials using a reusable piezoelectric impedance-based sensor

    International Nuclear Information System (INIS)

    Tawie, R; Lee, H K

    2011-01-01

    This paper proposes a reusable sensor, which employs a piezoceramic (PZT) plate as an active sensing transducer, for non-destructive monitoring of cement-based materials based on the electromechanical impedance (EMI) sensing technique. The advantage of the sensor design is that the PZT can be easily removed from the set-up and re-used for repetitive tests. The applicability of the sensor was demonstrated for monitoring of the setting of cement mortar. EMI measurements were performed using an impedance analyzer and the transformation of the specimen from the plastic to solid state was monitored by automatically measuring the changes in the PZT conductance spectra with respect to curing time using the root mean square deviation (RMSD) algorithm. In another experiment, drying-induced moisture loss of a hardened mortar specimen at saturated surface dry (SSD) condition was measured, and monitored using the reusable sensor to establish a correlation between the RMSD values and moisture loss rate. The reusable sensor was also demonstrated for detecting progressive damages imparted on a mortar specimen attached with the sensor under several loading levels before allowing it to load to failure. Overall, the reusable sensor is an effective and efficient monitoring device that could possibly be used for field application in characterization of cement-based materials

  15. Sensor-based material tagging system

    International Nuclear Information System (INIS)

    Vercellotti, L.C.; Cox, R.W.; Ravas, R.J.; Schlotterer, J.C.

    1991-01-01

    Electronic identification tags are being developed for tracking material and personnel. In applying electronic identification tags to radioactive materials safeguards, it is important to measure attributes of the material to ensure that the tag remains with the material. The addition of a microcontroller with an on-board analog-to-digital converter to an electronic identification tag application-specific integrated-circuit has been demonstrated as means to provide the tag with sensor data. Each tag is assembled into a housing, which serves as a scale for measuring the weight of a paint-can-sized container and its contents. Temperature rise of the can above ambient is also measured, and a piezoelectric detector detects disturbances and immediately puts the tag into its alarm and beacon mode. Radiation measurement was also considered, but the background from nearby containers was found to be excessive. The sensor-based tagging system allows tracking of the material in cans as it is stored in vaults or is moved through the manufacturing process. The paper presents details of the sensor-based material tagging system and describes a demonstration system

  16. Microfabricated Chemical Gas Sensors and Sensor Arrays for Aerospace Applications

    Science.gov (United States)

    Hunter, Gary W.

    2005-01-01

    Aerospace applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. In particular, factors such as minimal sensor size, weight, and power consumption are particularly important. Development areas which have potential aerospace applications include launch vehicle leak detection, engine health monitoring, and fire detection. Sensor development for these applications is based on progress in three types of technology: 1) Micromachining and microfabrication (Microsystem) technology to fabricate miniaturized sensors; 2) The use of nanocrystalline materials to develop sensors with improved stability combined with higher sensitivity; 3) The development of high temperature semiconductors, especially silicon carbide. This presentation discusses the needs of space applications as well as the point-contact sensor technology and sensor arrays being developed to address these needs. Sensors to measure hydrogen, hydrocarbons, nitrogen oxides (NO,), carbon monoxide, oxygen, and carbon dioxide are being developed as well as arrays for leak, fire, and emissions detection. Demonstrations of the technology will also be discussed. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  17. Optical hydrogen sensors based on metal-hydrides

    Science.gov (United States)

    Slaman, M.; Westerwaal, R.; Schreuders, H.; Dam, B.

    2012-06-01

    For many hydrogen related applications it is preferred to use optical hydrogen sensors above electrical systems. Optical sensors reduce the risk of ignition by spark formation and are less sensitive to electrical interference. Currently palladium and palladium alloys are used for most hydrogen sensors since they are well known for their hydrogen dissociation and absorption properties at relatively low temperatures. The disadvantages of palladium in sensors are the low optical response upon hydrogen loading, the cross sensitivity for oxygen and carbon, the limited detection range and the formation of micro-cracks after some hydrogen absorption/desorption cycles. In contrast to Pd, we find that the use of magnesium or rear earth bases metal-hydrides in optical hydrogen sensors allow tuning of the detection levels over a broad pressure range, while maintaining a high optical response. We demonstrate a stable detection layer for detecting hydrogen below 10% of the lower explosion limit in an oxygen rich environment. This detection layer is deposited at the bare end of a glass fiber as a micro-mirror and is covered with a thin layer of palladium. The palladium layer promotes the hydrogen uptake at room temperature and acts as a hydrogen selective membrane. To protect the sensor for a long time in air a final layer of a hydrophobic fluorine based coating is applied. Such a sensor can be used for example as safety detector in automotive applications. We find that this type of fiber optic hydrogen sensor is also suitable for hydrogen detection in liquids. As example we demonstrate a sensor for detecting a broad range of concentrations in transformer oil. Such a sensor can signal a warning when sparks inside a high voltage power transformer decompose the transformer oil over a long period.

  18. Monitoring Strategies of Earth Dams by Ground-Based Radar Interferometry: How to Extract Useful Information for Seismic Risk Assessment.

    Science.gov (United States)

    Di Pasquale, Andrea; Nico, Giovanni; Pitullo, Alfredo; Prezioso, Giuseppina

    2018-01-16

    The aim of this paper is to describe how ground-based radar interferometry can provide displacement measurements of earth dam surfaces and of vibration frequencies of its main concrete infrastructures. In many cases, dams were built many decades ago and, at that time, were not equipped with in situ sensors embedded in the structure when they were built. Earth dams have scattering properties similar to landslides for which the Ground-Based Synthetic Aperture Radar (GBSAR) technique has been so far extensively applied to study ground displacements. In this work, SAR and Real Aperture Radar (RAR) configurations are used for the measurement of earth dam surface displacements and vibration frequencies of concrete structures, respectively. A methodology for the acquisition of SAR data and the rendering of results is described. The geometrical correction factor, needed to transform the Line-of-Sight (LoS) displacement measurements of GBSAR into an estimate of the horizontal displacement vector of the dam surface, is derived. Furthermore, a methodology for the acquisition of RAR data and the representation of displacement temporal profiles and vibration frequency spectra of dam concrete structures is presented. For this study a Ku-band ground-based radar, equipped with horn antennas having different radiation patterns, has been used. Four case studies, using different radar acquisition strategies specifically developed for the monitoring of earth dams, are examined. The results of this work show the information that a Ku-band ground-based radar can provide to structural engineers for a non-destructive seismic assessment of earth dams.

  19. POSITIONING BASED ON INTEGRATION OF MUTI-SENSOR SYSTEMS USING KALMAN FILTER AND LEAST SQUARE ADJUSTMENT

    Directory of Open Access Journals (Sweden)

    M. Omidalizarandi

    2013-09-01

    Full Text Available Sensor fusion is to combine different sensor data from different sources in order to make a more accurate model. In this research, different sensors (Optical Speed Sensor, Bosch Sensor, Odometer, XSENS, Silicon and GPS receiver have been utilized to obtain different kinds of datasets to implement the multi-sensor system and comparing the accuracy of the each sensor with other sensors. The scope of this research is to estimate the current position and orientation of the Van. The Van's position can also be estimated by integrating its velocity and direction over time. To make these components work, it needs an interface that can bridge each other in a data acquisition module. The interface of this research has been developed based on using Labview software environment. Data have been transferred to PC via A/D convertor (LabJack and make a connection to PC. In order to synchronize all the sensors, calibration parameters of each sensor is determined in preparatory step. Each sensor delivers result in a sensor specific coordinate system that contains different location on the object, different definition of coordinate axes and different dimensions and units. Different test scenarios (Straight line approach and Circle approach with different algorithms (Kalman Filter, Least square Adjustment have been examined and the results of the different approaches are compared together.

  20. Electric field sensor studies

    International Nuclear Information System (INIS)

    Griffith, R.D.; Parks, S.

    1977-01-01

    Above-ground intrusion sensors are reviewed briefly. Buried wire sensors are next considered; feasibility studies were conducted. A triangular system of an overhead transmitter wire exciting two buried sensor wires was developed and tested. It failed sometimes to detect a man making a broad jump. A differential receiver was developed to solve this problem

  1. A Solar Position Sensor Based on Image Vision.

    Science.gov (United States)

    Ruelas, Adolfo; Velázquez, Nicolás; Villa-Angulo, Carlos; Acuña, Alexis; Rosales, Pedro; Suastegui, José

    2017-07-29

    Solar collector technologies operate with better performance when the Sun beam direction is normal to the capturing surface, and for that to happen despite the relative movement of the Sun, solar tracking systems are used, therefore, there are rules and standards that need minimum accuracy for these tracking systems to be used in solar collectors' evaluation. Obtaining accuracy is not an easy job, hence in this document the design, construction and characterization of a sensor based on a visual system that finds the relative azimuth error and height of the solar surface of interest, is presented. With these characteristics, the sensor can be used as a reference in control systems and their evaluation. The proposed sensor is based on a microcontroller with a real-time clock, inertial measurement sensors, geolocation and a vision sensor, that obtains the angle of incidence from the sunrays' direction as well as the tilt and sensor position. The sensor's characterization proved how a measurement of a focus error or a Sun position can be made, with an accuracy of 0.0426° and an uncertainty of 0.986%, which can be modified to reach an accuracy under 0.01°. The validation of this sensor was determined showing the focus error on one of the best commercial solar tracking systems, a Kipp & Zonen SOLYS 2. To conclude, the solar tracking sensor based on a vision system meets the Sun detection requirements and components that meet the accuracy conditions to be used in solar tracking systems and their evaluation or, as a tracking and orientation tool, on photovoltaic installations and solar collectors.

  2. Experimental Investigation on Admittance-Based Piezoelectric Sensor Diagnostic Process

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Hyejin; Park, Tongil; Park, Gyuhae [Chonnam National University, Gwangju (Korea, Republic of)

    2015-01-15

    Structural health monitoring (SHM) techniques based on the use of active-sensing piezoelectric (PZT) materials have received considerable attention. The validation of the PZT functionality during SHM operation is critical to successfully implementing a reliable SHM system. In this study, we investigated several parameters that affect the admittance-based sensor diagnostic process. We experimentally identified the temperature dependency of the active-sensor diagnostic process. We found that the admittance-based sensor diagnostic process can differentiate the adhesion conditions of bonding materials that are used to install a PZT on a structure, which is important when designing a sensor diagnostic process for an SHM system.

  3. Imprinted electrochemical sensor for dopamine recognition and determination based on a carbon nanotube/polypyrrole film

    International Nuclear Information System (INIS)

    Kan Xianwen; Zhou Hong; Li Chen; Zhu Anhong; Xing Zonglan; Zhao Zhe

    2012-01-01

    An electrochemical sensor combining a molecular imprinted technique and an electropolymerization method was developed in this work. A molecular imprinted polymer (MIP) film was fabricated by electropolymerizing pyrrole in the presence of dopamine (DA) after electrodepositing carboxyl-functionalized multi-walled carbon nanotubes (MWNTs-COOH) onto a glassy carbon electrode (GCE) surface. Scanning electron microscopy (SEM), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) were employed to characterize the constructed sensor. The effects of pH, the monomer concentration, the number of cycles for the electropolymerization, and the scan rate for the sensor preparation were optimized. The MIP-based sensor displayed an excellent recognition capacity toward DA compared with other structurally similar molecules. Additionally, the DPV peak current was linear to the DA concentration in the range from 6.25 × 10 −7 to 1 × 10 −4 mol/L, with a detection limit of 6 × 10 −8 mol/L. The prepared sensor also showed stable reproducibility and regeneration capacity.

  4. A Survey of Model-based Sensor Data Acquisition and Management

    OpenAIRE

    Aggarwal, Charu C.; Sathe, Saket; Papaioannou, Thanasis; Jeung, Hoyoung; Aberer, Karl

    2013-01-01

    In recent years, due to the proliferation of sensor networks, there has been a genuine need of researching techniques for sensor data acquisition and management. To this end, a large number of techniques have emerged that advocate model-based sensor data acquisition and management. These techniques use mathematical models for performing various, day-to-day tasks involved in managing sensor data. In this chapter, we survey the state-of-the-art techniques for model-based sensor data acquisition...

  5. Fully wireless pressure sensor based on endoscopy images

    Science.gov (United States)

    Maeda, Yusaku; Mori, Hirohito; Nakagawa, Tomoaki; Takao, Hidekuni

    2018-04-01

    In this paper, the result of developing a fully wireless pressure sensor based on endoscopy images for an endoscopic surgery is reported for the first time. The sensor device has structural color with a nm-scale narrow gap, and the gap is changed by air pressure. The structural color of the sensor is acquired from camera images. Pressure detection can be realized with existing endoscope configurations only. The inner air pressure of the human body should be measured under flexible-endoscope operation using the sensor. Air pressure monitoring, has two important purposes. The first is to quantitatively measure tumor size under a constant air pressure for treatment selection. The second purpose is to prevent the endangerment of a patient due to over transmission of air. The developed sensor was evaluated, and the detection principle based on only endoscopy images has been successfully demonstrated.

  6. LPG based all plastic pressure sensor

    DEFF Research Database (Denmark)

    Bundalo, Ivan-Lazar; Lwin, R.; Leon-Saval, S.

    2015-01-01

    A prototype all-plastic pressure sensor is presented and characterized for potential use as an endoscope. The sensor is based on Long Period Gratings (LPG) inscribed with a CO2 laser in 6-ring microstructured PMMA fiber. Through a latex coated, plastic 3D-printed transducer pod, external pressure...... is converted to longitudinal elongation of the pod and therefore of the fiber containing the LPG. The sensor has been characterised for pressures of up to 160 mBar in an in-house built pressure chamber. Furthermore, the influence of the fiber prestrain, fiber thickness and the effect of different glues...

  7. Using Gaia as an Astrometric Tool for Deep Ground-based Surveys

    Science.gov (United States)

    Casetti-Dinescu, Dana I.; Girard, Terrence M.; Schriefer, Michael

    2018-04-01

    Gaia DR1 positions are used to astrometrically calibrate three epochs' worth of Subaru SuprimeCam images in the fields of globular cluster NGC 2419 and the Sextans dwarf spheroidal galaxy. Distortion-correction ``maps'' are constructed from a combination of offset dithers and reference to Gaia DR1. These are used to derive absolute proper motions in the field of NGC 2419. Notably, we identify the photometrically-detected Monoceros structure in the foreground of NGC 2419 as a kinematically-cold population of stars, distinct from Galactic-field stars. This project demonstrates the feasibility of combining Gaia with deep, ground-based surveys, thus extending high-quality astrometry to magnitudes beyond the limits of Gaia.

  8. Demonstration of MPV Sensor at Yuma Proving Ground, AZ

    Science.gov (United States)

    2011-06-01

    test plot in Ashland, OR, where magnetic soils have shown to have a significant effect on EMI sensors ( Pasion et al., 2008). The recorded signal...sensors was also investigated during that survey as part of SERDP MM-1573 (PI: Len Pasion , Sky Research). The MPV offers possibilities to defeat...of magnetic soils (Lhomme et al., 2008; Pasion et al., 2008). The MPV response due to sensor motion and topography over magnetic soil is predicable

  9. Networked Sensor Arrays

    International Nuclear Information System (INIS)

    Tighe, R. J.

    2002-01-01

    A set of independent radiation sensors, coupled with real-time data telemetry, offers the opportunity to run correlation algorithms for the sensor array as well as to incorporate non-radiological data into the system. This may enhance the overall sensitivity of the sensors and provide an opportunity to project the location of a source within the array. In collaboration with Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories (SNL), we have conducted field experiments to test a prototype system. Combining the outputs of a set of distributed sensors permits the correlation that the independent sensor outputs. Combined with additional information such as traffic patterns and velocities, this can reduce random/false detections and enhance detection capability. The principle components of such a system include: (1) A set of radiation sensors. These may be of varying type and complexity, including gamma and/or neutron detectors, gross count and spectral-capable sensors, and low to high energy-resolution sensors. (2) A set of non-radiation sensors. These may include sensors such as vehicle presence and imaging sensors. (3) A communications architecture for near real-time telemetry. Depending upon existing infrastructure and bandwidth requirements, this may be a radio or hard-wire based system. (4) A central command console to pole the sensors, correlate their output, and display the data in a meaningful form to the system operator. Both sensitivity and selectivity are important considerations when evaluating the performance of a detection system. Depending on the application, the optimization of sensitivity as well as the rejection of ''nuisance'' radioactive sources may or may not be critical

  10. Airborne and satellite remote sensors for precision agriculture

    Science.gov (United States)

    Remote sensing provides an important source of information to characterize soil and crop variability for both within-season and after-season management despite the availability of numerous ground-based soil and crop sensors. Remote sensing applications in precision agriculture have been steadily inc...

  11. Water-Cut Sensor System

    KAUST Repository

    Karimi, Muhammad Akram; Shamim, Atif; Arsalan, Muhammad

    2018-01-01

    Provided in some embodiments is a method of manufacturing a pipe conformable water-cut sensors system. Provided in some embodiments is method for manufacturing a water-cut sensor system that includes providing a helical T-resonator, a helical ground

  12. Combining Fog Computing with Sensor Mote Machine Learning for Industrial IoT.

    Science.gov (United States)

    Lavassani, Mehrzad; Forsström, Stefan; Jennehag, Ulf; Zhang, Tingting

    2018-05-12

    Digitalization is a global trend becoming ever more important to our connected and sustainable society. This trend also affects industry where the Industrial Internet of Things is an important part, and there is a need to conserve spectrum as well as energy when communicating data to a fog or cloud back-end system. In this paper we investigate the benefits of fog computing by proposing a novel distributed learning model on the sensor device and simulating the data stream in the fog, instead of transmitting all raw sensor values to the cloud back-end. To save energy and to communicate as few packets as possible, the updated parameters of the learned model at the sensor device are communicated in longer time intervals to a fog computing system. The proposed framework is implemented and tested in a real world testbed in order to make quantitative measurements and evaluate the system. Our results show that the proposed model can achieve a 98% decrease in the number of packets sent over the wireless link, and the fog node can still simulate the data stream with an acceptable accuracy of 97%. We also observe an end-to-end delay of 180 ms in our proposed three-layer framework. Hence, the framework shows that a combination of fog and cloud computing with a distributed data modeling at the sensor device for wireless sensor networks can be beneficial for Industrial Internet of Things applications.

  13. An Overview of Pesticide Monitoring at Environmental Samples Using Carbon Nanotubes-Based Electrochemical Sensors

    Directory of Open Access Journals (Sweden)

    Ademar Wong

    2017-03-01

    Full Text Available Carbon nanotubes have received enormous attention in the development of electrochemical sensors by promoting electron transfer reactions, decreasing the work overpotential within great surface areas. The growing concerns about environmental health emphasized the necessity of continuous monitoring of pollutants. Pesticides have been successfully used to control agricultural and public health pests; however, intense use can cause a number of damages for biodiversity and human health. In this sense, carbon nanotubes-based electrochemical sensors have been proposed for pesticide monitoring combining different electrode modification strategies and electroanalytical techniques. In this paper, we provide a review of the recent advances in the use of carbon nanotubes for the construction of electrochemical sensors dedicated to the environmental monitoring of pesticides. Future directions, perspectives, and challenges are also commented.

  14. Circuit Design of Surface Acoustic Wave Based Micro Force Sensor

    Directory of Open Access Journals (Sweden)

    Yuanyuan Li

    2014-01-01

    Full Text Available Pressure sensors are commonly used in industrial production and mechanical system. However, resistance strain, piezoresistive sensor, and ceramic capacitive pressure sensors possess limitations, especially in micro force measurement. A surface acoustic wave (SAW based micro force sensor is designed in this paper, which is based on the theories of wavelet transform, SAW detection, and pierce oscillator circuits. Using lithium niobate as the basal material, a mathematical model is established to analyze the frequency, and a peripheral circuit is designed to measure the micro force. The SAW based micro force sensor is tested to show the reasonable design of detection circuit and the stability of frequency and amplitude.

  15. Sleep Scheduling Schemes Based on Location of Mobile User in Sensor-Cloud

    OpenAIRE

    N. Mahendran; R. Priya

    2016-01-01

    The mobile cloud computing (MCC) with wireless sensor networks (WSNs) technology gets more attraction by research scholars because its combines the sensors data gathering ability with the cloud data processing capacity. This approach overcomes the limitation of data storage capacity and computational ability of sensor nodes. Finally, the stored data are sent to the mobile users when the user sends the request. The most of the integrated sensor-cloud schemes fail to observe the following crite...

  16. A 35 GHz wireless millimeter-wave power sensor based on GaAs micromachining technology

    International Nuclear Information System (INIS)

    Wang, De-bo; Liao, Xiao-ping

    2012-01-01

    A novel MEMS wireless millimeter-wave power sensor based on GaAs MMIC technology is presented in this paper. The principle of this wireless millimeter-wave power sensor is explained. It is designed and fabricated using MEMS technology and the GaAs MMIC process. With the millimeter-wave power range from 0.1 to 80 mW, the sensitivity of the wireless millimeter-wave power sensor is about 0.246 mV mW −1 at 35 GHz. In order to verify the power detection capability, this wireless power sensor is mounted on a PCB which influences the microwave performance of the CPW-fed antenna including the return loss and the radiation pattern. The frequency-dependent characteristic and the degree-dependent characteristic of this wireless power sensor are researched. Furthermore, in addition to the combination of the advantages of CPW-fed antenna with the advantages of the thermoelectric power sensor, another significant advantage of this wireless millimeter-wave power sensor is that it can be integrated with MMICs and other planar connecting circuit structures with zero dc power consumption. These features make it suitable for various applications ranging from the environment or space radiation detection systems to radar receiver and transmitter systems. (paper)

  17. Inline chemical process analysis in micro-plants based on thermoelectric flow and impedimetric sensors

    International Nuclear Information System (INIS)

    Jacobs, T; Kutzner, C; Hauptmann, P; Kropp, M; Lang, W; Brokmann, G; Steinke, A; Kienle, A

    2010-01-01

    In micro-plants, as used in chemical micro-process engineering, an integrated inline analytics is regarded as an important factor for the development and optimization of chemical processes. Up to now, there is a lack of sensitive, robust and low-priced micro-sensors for monitoring mixing and chemical conversion in micro-fluidic channels. In this paper a novel sensor system combining an impedimetric sensor and a novel pressure stable thermoelectric flow sensor for monitoring chemical reactions in micro-plants is presented. The CMOS-technology-based impedimetric sensor mainly consists of two capacitively coupled interdigital electrodes on a silicon chip. The thermoelectric flow sensor consists of a heater in between two thermopiles on a perforated membrane. The pulsed and constant current feeds of the heater were analyzed. Both sensors enable the analysis of chemical conversion by means of changes in the thermal and electrical properties of the liquid. The homogeneously catalyzed synthesis of n-butyl acetate as a chemical model system was studied. Experimental results revealed that in an overpressure regime, relative changes of less than 1% in terms of thermal and electrical properties can be detected. Furthermore, the transition from one to two liquid phases accompanied by the change in slug flow conditions could be reproducibly detected

  18. An integrated multi-sensor fusion-based deep feature learning approach for rotating machinery diagnosis

    Science.gov (United States)

    Liu, Jie; Hu, Youmin; Wang, Yan; Wu, Bo; Fan, Jikai; Hu, Zhongxu

    2018-05-01

    The diagnosis of complicated fault severity problems in rotating machinery systems is an important issue that affects the productivity and quality of manufacturing processes and industrial applications. However, it usually suffers from several deficiencies. (1) A considerable degree of prior knowledge and expertise is required to not only extract and select specific features from raw sensor signals, and but also choose a suitable fusion for sensor information. (2) Traditional artificial neural networks with shallow architectures are usually adopted and they have a limited ability to learn the complex and variable operating conditions. In multi-sensor-based diagnosis applications in particular, massive high-dimensional and high-volume raw sensor signals need to be processed. In this paper, an integrated multi-sensor fusion-based deep feature learning (IMSFDFL) approach is developed to identify the fault severity in rotating machinery processes. First, traditional statistics and energy spectrum features are extracted from multiple sensors with multiple channels and combined. Then, a fused feature vector is constructed from all of the acquisition channels. Further, deep feature learning with stacked auto-encoders is used to obtain the deep features. Finally, the traditional softmax model is applied to identify the fault severity. The effectiveness of the proposed IMSFDFL approach is primarily verified by a one-stage gearbox experimental platform that uses several accelerometers under different operating conditions. This approach can identify fault severity more effectively than the traditional approaches.

  19. Airfield Ground Safety

    National Research Council Canada - National Science Library

    Petrescu, Jon

    2000-01-01

    .... The system developed under AGS, called the Ground Safety Tracking and Reporting System, uses multisensor data fusion from in-pavement inductive loop sensors to address a critical problem affecting out nation's airports: runway incursions...

  20. An H2S Sensor Based on Electrochemistry for Chicken Coops

    Science.gov (United States)

    Zeng, Lihua; He, Mei; Yu, Huihui; Li, Daoliang

    2016-01-01

    The recent modernization of the livestock industry lags behind the scale of the livestock industry, particularly in indoor environmental monitoring. In particular, the H2S gas concentration in chicken coops affects the growth and reproductive capacity of the chickens and threatens their health. Therefore, the research and development of a low-cost, environmentally friendly sensor that can achieve on-line monitoring of H2S gas has a notably important practical significance. This paper reports the design of an H2S gas sensor, with selection of an electrochemical probe with high accuracy and wide measurement range using the relatively mature technology of electrochemical sensors. Although the probe of the sensor is the main factor that affects the sensor accuracy, the probe must be combined with a specifically designed signal condition circuit that can overcome the lack of an electrode to satisfy the requirements for the interconnection and matching between the output signal and the test instrument. Because the output current of the electrochemical electrode is small and likely to be disturbed by noise, we designed signal-conditioning modules. Through the signal-conditioning circuit, the output signal of the current electrode can be converted into a voltage and amplified. In addition, we designed a power control module because a bias voltage is necessary for the electrode. Finally, after the calibration experiment, the accurate concentration of H2S gas can be measured. Based on the experimental analysis, the sensor shows good linearity and selectivity, comparatively high sensitivity, perfect stability and an extremely long operating life of up to two years. PMID:27589757

  1. Combined Voltammetric-Potentiometric Sensor with the Silver Solid Amalgam Link for Electroanalytical Measurements

    Czech Academy of Sciences Publication Activity Database

    Josypčuk, Bohdan; Novotný, Ladislav

    2002-01-01

    Roč. 14, č. 24 (2002), s. 1739-1741 ISSN 1040-0397 R&D Projects: GA ČR GV204/97/K084 Institutional research plan: CEZ:AV0Z4040901 Keywords : combined voltammetric-potentiometric sensors * solid amalgam Subject RIV: CG - Electrochemistry Impact factor: 1.783, year: 2002

  2. ISFET based enzyme sensors

    NARCIS (Netherlands)

    van der Schoot, Bart H.; Bergveld, Piet

    1987-01-01

    This paper reviews the results that have been reported on ISFET based enzyme sensors. The most important improvement that results from the application of ISFETs instead of glass membrane electrodes is in the method of fabrication. Problems with regard to the pH dependence of the response and the

  3. A MEMS SOI-based piezoresistive fluid flow sensor

    Science.gov (United States)

    Tian, B.; Li, H. F.; Yang, H.; Song, D. L.; Bai, X. W.; Zhao, Y. L.

    2018-02-01

    In this paper, a SOI (silicon-on-insulator)-based piezoresistive fluid flow sensor is presented; the presented flow sensor mainly consists of a nylon sensing head, stainless steel cantilever beam, SOI sensor chip, printed circuit board, half-cylinder gasket, and stainless steel shell. The working principle of the sensor and some detailed contrastive analysis about the sensor structure were introduced since the nylon sensing head and stainless steel cantilever beam have distinct influence on the sensor performance; the structure of nylon sensing head and stainless steel cantilever beam is also discussed. The SOI sensor chip was fabricated using micro-electromechanical systems technologies, such as reactive ion etching and low pressure chemical vapor deposition. The designed fluid sensor was packaged and tested; a calibration installation system was purposely designed for the sensor experiment. The testing results indicated that the output voltage of the sensor is proportional to the square of the fluid flow velocity, which is coincident with the theoretical derivation. The tested sensitivity of the sensor is 3.91 × 10-4 V ms2/kg.

  4. Infrasound Sensor and Porous-Hose Filter Characterization Results

    Science.gov (United States)

    Hart, D. M.; Harris, J. M.

    2008-12-01

    The Ground-Based Nuclear Explosion Monitoring Research and Development (GNEM R&D) program at Sandia National Laboratories (SNL) is regarded as the primary center for unbiased expertise in testing and evaluation of geophysical sensors and instrumentation for nuclear explosion monitoring. Over the past year much of our work has focused in the area of infrasound sensor characterization through the continuing development of an infrasound sensor characterization test-bed. Our main areas of focus have been in new sensor characterization and understanding the effects of porous-hose filters for reducing acoustic background signals. Three infrasound sensors were evaluated for characteristics of instrument response, linearity and self-noise. The sensors tested were Chaparral Physics model 2.5 low-gain, New Mexico Tech All-Sensor and the Inter-Mountain Labs model SS avalanche sensor. For the infrasound sensors tested, the test results allow us to conclude that two of the three sensors had sufficiently quiet noise floor to be at or below the Acoustic low-noise model from 0.1 to 7 Hz, which make those sensors suitable to explosion monitoring. The other area of focus has been to understand the characteristics of porous-hose filters used at some monitoring sites. For this, an experiment was designed in which two infrasound sensors were co- located. One sensor was connected to a typical porous-hose spatial filter consisting of eight individual hoses covering a 30m aperture and the second sensor was left open to unimpeded acoustic input. Data were collected for several days, power spectrum computed for two-hour windows and the relative gain of the porous-hose filters were estimated by dividing the power spectrum. The porous-hose filter appears to attenuate less than 3 dB (rel 1 Pa**2/Hz) below 0.1 Hz and as much as 25 dB at 1 Hz and between 20 to 10 dB above 10 Hz. Several more experiments will be designed to address the effects of different characteristics of the individual porous

  5. Low-cost sensors to monitor groundwater drought in Somalia

    Science.gov (United States)

    Buytaert, W.; Ochoa-Tocachi, B. F.; Caniglia, D.; Haibe, K.; Butler, A. P.

    2017-12-01

    Somalia is one of the poorest countries in the world, devastated by conflict and suffering from the most severe droughts in living memory. Over 6 million people are in need of assistance, and about 3 million are threatened with famine. In April 2017, the WHO estimated that more than 25,000 people have been struck by cholera or acute watery diarrhoea and this number is rising quickly. About half a million Somalis have been displaced internally, many of which in search of water. Some 3 million pastoralists have lost 70% of livestock as a result of the drought. Humanitarian organisations and government agencies invest large amounts of resources to alleviate these conditions. It is paramount to inform the design, focus, and optimisation of these interventions by monitoring and quantifying water resources. Yet, regions such as Somalia are extremely sparsely gauged as a result of a combination of lack of resources and technical expertise, as well as the harsh geographical and geopolitical conditions. Low-cost, robust, and reliable sensors may provide a potential solution to this problem. We present the results of a research project that aimed to leverage new developments in sensor, logger, and data transmission technologies to develop low-cost water level sensors to monitor hand-dug groundwater wells in real time. We tested 3 types of sensor types, i.e. pressure transducers, ultrasound-based distance sensors, and lidar, which were coupled to low-cost logging systems. The different designs were tested both in laboratory conditions, and in-situ in hand-dug wells in Somaliland. Our results show that it is technically possible to build sensors with a total cost of around US$250 each, which are fit-for-purpose for the required application. In-situ deployment over a period of 2 months highlights their robustness despite severe logistical and practical challenges, though further tests are required to understand their long-term reliability. Operating the sensors at one

  6. Cloud-to-Ground Lightning Estimates Derived from SSMI Microwave Remote Sensing and NLDN

    Science.gov (United States)

    Winesett, Thomas; Magi, Brian; Cecil, Daniel

    2015-01-01

    Lightning observations are collected using ground-based and satellite-based sensors. The National Lightning Detection Network (NLDN) in the United States uses multiple ground sensors to triangulate the electromagnetic signals created when lightning strikes the Earth's surface. Satellite-based lightning observations have been made from 1998 to present using the Lightning Imaging Sensor (LIS) on the NASA Tropical Rainfall Measuring Mission (TRMM) satellite, and from 1995 to 2000 using the Optical Transient Detector (OTD) on the Microlab-1 satellite. Both LIS and OTD are staring imagers that detect lightning as momentary changes in an optical scene. Passive microwave remote sensing (85 and 37 GHz brightness temperatures) from the TRMM Microwave Imager (TMI) has also been used to quantify characteristics of thunderstorms related to lightning. Each lightning detection system has fundamental limitations. TRMM satellite coverage is limited to the tropics and subtropics between 38 deg N and 38 deg S, so lightning at the higher latitudes of the northern and southern hemispheres is not observed. The detection efficiency of NLDN sensors exceeds 95%, but the sensors are only located in the USA. Even if data from other ground-based lightning sensors (World Wide Lightning Location Network, the European Cooperation for Lightning Detection, and Canadian Lightning Detection Network) were combined with TRMM and NLDN, there would be enormous spatial gaps in present-day coverage of lightning. In addition, a globally-complete time history of observed lightning activity is currently not available either, with network coverage and detection efficiencies varying through the years. Previous research using the TRMM LIS and Microwave Imager (TMI) showed that there is a statistically significant correlation between lightning flash rates and passive microwave brightness temperatures. The physical basis for this correlation emerges because lightning in a thunderstorm occurs where ice is first

  7. Coordinated Ground-Based Observations and the New Horizons Fly-by of Pluto

    Science.gov (United States)

    Young, Eliot; Young, Leslie; Parker, Joel; Binzel, Richard

    2015-04-01

    The New Horizons (NH) spacecraft is scheduled to make its closest approach to Pluto on July 14, 2015. NH carries seven scientific instruments, including separate UV and Visible-IR spectrographs, a long-focal-length imager, two plasma-sensing instruments and a dust counter. There are three arenas in particular in which ground-based observations should augment the NH instrument suite in synergistic ways: IR spectra at wavelengths longer than 2.5 µm (i.e., longer than the NH Ralph spectrograph), stellar occultation observations near the time of the fly-by, and thermal surface maps and atmospheric CO abundances based on ALMA observations - we discuss the first two of these. IR spectra in the 3 - 5 µm range cover the CH4 absorption band near 3.3 µm. This band can be an important constraint on the state and areal extent of nitrogen frost on Pluto's surface. If this band depth is close to zero (as was observed by Olkin et al. 2007), it limits the area of nitrogen frost, which is bright at that wavelength. Combined with the NH observations of nitrogen frost at 2.15 µm, the ground-based spectra will determine how much nitrogen frost is diluted with methane, which is a basic constraint on the seasonal cycle of sublimation and condensation that takes place on Pluto (and similar objects like Triton and Eris). There is a fortuitous stellar occultation by Pluto on 29-JUN-2015, only two weeks before the NH closest approach. The occulted star will be the brightest ever observed in a Pluto event, about 2 magnitudes brighter than Pluto itself. The track of the event is predicted to cover parts of Australia and New Zealand. Thanks to HST and ground based campaigns to find a TNO target reachable by NH, the position of the shadow path will be known at the +/-100 km level, allowing SOFIA and mobile ground-based observers to reliably cover the central flash region. Ground-based & SOFIA observations in visible and IR wavelengths will characterize the haze opacity and vertical

  8. Fluorescent pH sensor based on Ag@SiO2 core-shell nanoparticle.

    Science.gov (United States)

    Bai, Zhenhua; Chen, Rui; Si, Peng; Huang, Youju; Sun, Handong; Kim, Dong-Hwan

    2013-06-26

    We have demonstrated a novel method for the preparation of a fluorescence-based pH sensor by combining the plasmon resonance band of Ag core and pH sensitive dye (HPTS). A thickness-variable silica shell is placed between Ag core and HPTS dye to achieve the maximum fluorescence enhancement. At the shell thickness of 8 nm, the fluorescence intensity increases 4 and 9 times when the sensor is excited at 405 and 455 nm, respectively. At the same time, the fluorescence intensity shows a good sensitivity toward pH value in the range of 5-9, and the ratio of emission intensity at 513 nm excited at 455 nm to that excited at 405 nm versus the pH value in the range of 5-9 is determined. It is believed that the present pH sensor has the potential for determining pH real time in the biological sample.

  9. Development of a Waterproof Crack-Based Stretchable Strain Sensor Based on PDMS Shielding

    Directory of Open Access Journals (Sweden)

    Seong Kyung Hong

    2018-04-01

    Full Text Available This paper details the design of a poly(dimethylsiloxane (PDMS-shielded waterproof crack-based stretchable strain sensor, in which the electrical characteristics and sensing performance are not influenced by changes in humidity. This results in a higher number of potential applications for the sensor. A previously developed omni-purpose stretchable strain (OPSS sensor was used as the basis for this work, which utilizes a metal cracking structure and provides a wide sensing range and high sensitivity. Changes in the conductivity of the OPSS sensor, based on humidity conditions, were investigated along with the potential possibility of using the design as a humidity sensor. However, to prevent conductivity variation, which can decrease the reliability and sensing ability of the OPSS sensor, PDMS was utilized as a shielding layer over the OPSS sensor. The PDMS-shielded OPSS sensor showed approximately the same electrical characteristics as previous designs, including in a high humidity environment, while maintaining its strain sensing capabilities. The developed sensor shows promise for use under high humidity conditions and in underwater applications. Therefore, considering its unique features and reliable sensing performance, the developed PDMS-shielded waterproof OPSS sensor has potential utility in a wide range of applications, such as motion monitoring, medical robotics and wearable healthcare devices.

  10. Development of a Waterproof Crack-Based Stretchable Strain Sensor Based on PDMS Shielding.

    Science.gov (United States)

    Hong, Seong Kyung; Yang, Seongjin; Cho, Seong J; Jeon, Hyungkook; Lim, Geunbae

    2018-04-12

    This paper details the design of a poly(dimethylsiloxane) (PDMS)-shielded waterproof crack-based stretchable strain sensor, in which the electrical characteristics and sensing performance are not influenced by changes in humidity. This results in a higher number of potential applications for the sensor. A previously developed omni-purpose stretchable strain (OPSS) sensor was used as the basis for this work, which utilizes a metal cracking structure and provides a wide sensing range and high sensitivity. Changes in the conductivity of the OPSS sensor, based on humidity conditions, were investigated along with the potential possibility of using the design as a humidity sensor. However, to prevent conductivity variation, which can decrease the reliability and sensing ability of the OPSS sensor, PDMS was utilized as a shielding layer over the OPSS sensor. The PDMS-shielded OPSS sensor showed approximately the same electrical characteristics as previous designs, including in a high humidity environment, while maintaining its strain sensing capabilities. The developed sensor shows promise for use under high humidity conditions and in underwater applications. Therefore, considering its unique features and reliable sensing performance, the developed PDMS-shielded waterproof OPSS sensor has potential utility in a wide range of applications, such as motion monitoring, medical robotics and wearable healthcare devices.

  11. A frequency output ferroelectric phase PNZT capacitor-based temperature sensor

    KAUST Repository

    Khan, Naveed

    2016-09-05

    In this paper, a frequency output temperature sensor based on a 4% Niobium doped 20/80 Zr/Ti Lead Zirconate Titanate (PNZT) capacitor is proposed. The sensor capacitance vs temperature and capacitance vs voltage characteristics are experimentally measured below the Curie temperature of the ferroelectric capacitor. The capacitance of the 20/80 (Zr/Ti) composition PNZT capacitor changes by 29% for a temperature change from 10°C to 100°C, which translates to 0.32%/°C temperature sensitivity. The measured sensor characteristics show less than ∼0.7°C deviation from the ideal linear response. A Wien bridge oscillator based temperature sensor is demonstrated based on the PNZT capacitors. Mathematical analysis for the effect of the op-amp finite unity-gain frequency on the sensor circuit oscillation frequency is provided. The experimentally realized frequency output temperature sensor shows -17.6% relative frequency change for a temperature change from 10°C to 100°C. The proposed capacitive temperature sensor can be used in low-power smart sensor nodes without the need for extensive calibration. © 2015 IEEE.

  12. Planar Zeolite Film-Based Potentiometric Gas Sensors Manufactured by a Combined Thick-Film and Electroplating Technique

    Science.gov (United States)

    Marr, Isabella; Reiß, Sebastian; Hagen, Gunter; Moos, Ralf

    2011-01-01

    Zeolites are promising materials in the field of gas sensors. In this technology-oriented paper, a planar setup for potentiometric hydrocarbon and hydrogen gas sensors using zeolites as ionic sodium conductors is presented, in which the Pt-loaded Na-ZSM-5 zeolite is applied using a thick-film technique between two interdigitated gold electrodes and one of them is selectively covered for the first time by an electroplated chromium oxide film. The influence of the sensor temperature, the type of hydrocarbons, the zeolite film thickness, and the chromium oxide film thickness is investigated. The influence of the zeolite on the sensor response is briefly discussed in the light of studies dealing with zeolites as selectivity-enhancing cover layers. PMID:22164042

  13. Planar Zeolite Film-Based Potentiometric Gas Sensors Manufactured by a Combined Thick-Film and Electroplating Technique

    Directory of Open Access Journals (Sweden)

    Gunter Hagen

    2011-08-01

    Full Text Available Zeolites are promising materials in the field of gas sensors. In this technology-oriented paper, a planar setup for potentiometric hydrocarbon and hydrogen gas sensors using zeolites as ionic sodium conductors is presented, in which the Pt-loaded Na-ZSM-5 zeolite is applied using a thick-film technique between two interdigitated gold electrodes and one of them is selectively covered for the first time by an electroplated chromium oxide film. The influence of the sensor temperature, the type of hydrocarbons, the zeolite film thickness, and the chromium oxide film thickness is investigated. The influence of the zeolite on the sensor response is briefly discussed in the light of studies dealing with zeolites as selectivity-enhancing cover layers.

  14. Wavelet-based ground vehicle recognition using acoustic signals

    Science.gov (United States)

    Choe, Howard C.; Karlsen, Robert E.; Gerhart, Grant R.; Meitzler, Thomas J.

    1996-03-01

    We present, in this paper, a wavelet-based acoustic signal analysis to remotely recognize military vehicles using their sound intercepted by acoustic sensors. Since expedited signal recognition is imperative in many military and industrial situations, we developed an algorithm that provides an automated, fast signal recognition once implemented in a real-time hardware system. This algorithm consists of wavelet preprocessing, feature extraction and compact signal representation, and a simple but effective statistical pattern matching. The current status of the algorithm does not require any training. The training is replaced by human selection of reference signals (e.g., squeak or engine exhaust sound) distinctive to each individual vehicle based on human perception. This allows a fast archiving of any new vehicle type in the database once the signal is collected. The wavelet preprocessing provides time-frequency multiresolution analysis using discrete wavelet transform (DWT). Within each resolution level, feature vectors are generated from statistical parameters and energy content of the wavelet coefficients. After applying our algorithm on the intercepted acoustic signals, the resultant feature vectors are compared with the reference vehicle feature vectors in the database using statistical pattern matching to determine the type of vehicle from where the signal originated. Certainly, statistical pattern matching can be replaced by an artificial neural network (ANN); however, the ANN would require training data sets and time to train the net. Unfortunately, this is not always possible for many real world situations, especially collecting data sets from unfriendly ground vehicles to train the ANN. Our methodology using wavelet preprocessing and statistical pattern matching provides robust acoustic signal recognition. We also present an example of vehicle recognition using acoustic signals collected from two different military ground vehicles. In this paper, we will

  15. Self-Similarity Superresolution for Resource-Constrained Image Sensor Node in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yuehai Wang

    2014-01-01

    Full Text Available Wireless sensor networks, in combination with image sensors, open up a grand sensing application field. It is a challenging problem to recover a high resolution (HR image from its low resolution (LR counterpart, especially for low-cost resource-constrained image sensors with limited resolution. Sparse representation-based techniques have been developed recently and increasingly to solve this ill-posed inverse problem. Most of these solutions are based on an external dictionary learned from huge image gallery, consequently needing tremendous iteration and long time to match. In this paper, we explore the self-similarity inside the image itself, and propose a new combined self-similarity superresolution (SR solution, with low computation cost and high recover performance. In the self-similarity image super resolution model (SSIR, a small size sparse dictionary is learned from the image itself by the methods such as KSVD. The most similar patch is searched and specially combined during the sparse regulation iteration. Detailed information, such as edge sharpness, is preserved more faithfully and clearly. Experiment results confirm the effectiveness and efficiency of this double self-learning method in the image super resolution.

  16. Model Based Optimal Sensor Network Design for Condition Monitoring in an IGCC Plant

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rajeeva; Kumar, Aditya; Dai, Dan; Seenumani, Gayathri; Down, John; Lopez, Rodrigo

    2012-12-31

    these two formulations were developed and validated. For a given OSP problem the computation efficiency largely depends on the “size” of the problem. Initially a simplified 1-D gasifier model assuming axial and azimuthal symmetry was used to test out various OSP algorithms. Finally these algorithms were used to design the optimal sensor network for condition monitoring of IGCC gasifier refractory wear and RSC fouling. The sensors type and locations obtained as solution to the OSP problem were validated using model based sensing approach. The OSP algorithm has been developed in a modular form and has been packaged as a software tool for OSP design where a designer can explore various OSP design algorithm is a user friendly way. The OSP software tool is implemented in Matlab/Simulink© in-house. The tool also uses few optimization routines that are freely available on World Wide Web. In addition a modular Extended Kalman Filter (EKF) block has also been developed in Matlab/Simulink© which can be utilized for model based sensing of important process variables that are not directly measured through combining the online sensors with model based estimation once the hardware sensor and their locations has been finalized. The OSP algorithm details and the results of applying these algorithms to obtain optimal sensor location for condition monitoring of gasifier refractory wear and RSC fouling profile are summarized in this final report.

  17. Microbial BOD sensors based on Zr (IV)-loaded collagen fiber.

    Science.gov (United States)

    Zhao, Lei; He, Li; Chen, Shujuan; Zou, Likou; Zhou, Kang; Ao, Xiaolin; Liu, Shuliang; Hu, Xinjie; Han, Guoquan

    2017-03-01

    Biochemical oxygen demand (BOD) sensors based on Zr (IV)-loaded collagen fiber (ZrCF), a novel material with great porous structure, were developed. This novel material shows adsorbability by microorganisms. Saccharomyces cerevisiae and Escherichia coli were used for the construction of BOD sensors. Factors affecting BOD sensor performance were examined. The ZrCF-based BOD sensor showed different sensitivities and linear response ranges with different biofilm densities. The amount of microorganisms strongly affected the performance of the BOD sensor. Poor permeability of previously reported immobilization carriers were greatly circumvented by ZrCF. The service life of the ZrCF-based BOD sensor was more than 42 days. The immobilized microorganisms can be stored for more than 6 months under 4°C in PB solution. There was good correlation between the results of the sensor method and the standard 5-day BOD method in the determination of pure organic substrates and real water samples. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Integrated Temperature Sensors based on Heat Diffusion

    NARCIS (Netherlands)

    Van Vroonhoven, C.P.L.

    2015-01-01

    This thesis describes the theory, design and implementation of a new class of integrated temperature sensors, based on heat diffusion. In such sensors, temperature is sensed by measuring the time it takes for heat to diffuse through silicon. An on-chip thermal delay can be determined by geometry and

  19. Ground robotic measurement of aeolian processes

    Science.gov (United States)

    Qian, Feifei; Jerolmack, Douglas; Lancaster, Nicholas; Nikolich, George; Reverdy, Paul; Roberts, Sonia; Shipley, Thomas; Van Pelt, R. Scott; Zobeck, Ted M.; Koditschek, Daniel E.

    2017-08-01

    Models of aeolian processes rely on accurate measurements of the rates of sediment transport by wind, and careful evaluation of the environmental controls of these processes. Existing field approaches typically require intensive, event-based experiments involving dense arrays of instruments. These devices are often cumbersome and logistically difficult to set up and maintain, especially near steep or vegetated dune surfaces. Significant advances in instrumentation are needed to provide the datasets that are required to validate and improve mechanistic models of aeolian sediment transport. Recent advances in robotics show great promise for assisting and amplifying scientists' efforts to increase the spatial and temporal resolution of many environmental measurements governing sediment transport. The emergence of cheap, agile, human-scale robotic platforms endowed with increasingly sophisticated sensor and motor suites opens up the prospect of deploying programmable, reactive sensor payloads across complex terrain in the service of aeolian science. This paper surveys the need and assesses the opportunities and challenges for amassing novel, highly resolved spatiotemporal datasets for aeolian research using partially-automated ground mobility. We review the limitations of existing measurement approaches for aeolian processes, and discuss how they may be transformed by ground-based robotic platforms, using examples from our initial field experiments. We then review how the need to traverse challenging aeolian terrains and simultaneously make high-resolution measurements of critical variables requires enhanced robotic capability. Finally, we conclude with a look to the future, in which robotic platforms may operate with increasing autonomy in harsh conditions. Besides expanding the completeness of terrestrial datasets, bringing ground-based robots to the aeolian research community may lead to unexpected discoveries that generate new hypotheses to expand the science

  20. Hydrogen sensor based on palladium-yttrium alloy nanosheet

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Boyi [Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan, QLD 4111 (Australia); Zhu, Yong, E-mail: y.zhu@griffith.edu.au [Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan, QLD 4111 (Australia); Chen, Youping; Song, Han; Huang, Pengcheng [School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074 (China); Dao, Dzung Viet [Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan, QLD 4111 (Australia)

    2017-06-15

    This paper presents a hydrogen sensor based on palladium-yttrium (Pd-Y) alloy nanosheet. Zigzag-shaped Pd-Y nanosheet with a thickness of 19.3 nm was deposited on a quartz substrate by using an ultrahigh-vacuum magnetron sputtering system and shadow mask. The atomic ratio of palladium to yttrium in the nanosheet was 0.92/0.08. The fabrication process was simple and low-cost, and the sensor can be mass-produced. The experimental results show the sensor has a superior sensitivity, reversibility, and reproducibility. The resistive-based hydrogen detection mechanism in this research is much simpler and more compact compared to the optical-based detection method. - Highlights: • Pd-Y sensing element was fabricated using a magnetron sputtering system and shadow mask. • The Pd-Y compound consisted of 92% Pd and 8% Y. • The fabrication process was simple, low-cost, and mass-production compatible. • The sensor showed superior sensitivity, reversibility, and reproducibility to hydrogen gas. • The device is more compact than the optical-based counterpart.

  1. Hydrogen sensor based on palladium-yttrium alloy nanosheet

    International Nuclear Information System (INIS)

    Wang, Boyi; Zhu, Yong; Chen, Youping; Song, Han; Huang, Pengcheng; Dao, Dzung Viet

    2017-01-01

    This paper presents a hydrogen sensor based on palladium-yttrium (Pd-Y) alloy nanosheet. Zigzag-shaped Pd-Y nanosheet with a thickness of 19.3 nm was deposited on a quartz substrate by using an ultrahigh-vacuum magnetron sputtering system and shadow mask. The atomic ratio of palladium to yttrium in the nanosheet was 0.92/0.08. The fabrication process was simple and low-cost, and the sensor can be mass-produced. The experimental results show the sensor has a superior sensitivity, reversibility, and reproducibility. The resistive-based hydrogen detection mechanism in this research is much simpler and more compact compared to the optical-based detection method. - Highlights: • Pd-Y sensing element was fabricated using a magnetron sputtering system and shadow mask. • The Pd-Y compound consisted of 92% Pd and 8% Y. • The fabrication process was simple, low-cost, and mass-production compatible. • The sensor showed superior sensitivity, reversibility, and reproducibility to hydrogen gas. • The device is more compact than the optical-based counterpart.

  2. Flexible Graphene-Based Wearable Gas and Chemical Sensors.

    Science.gov (United States)

    Singh, Eric; Meyyappan, M; Nalwa, Hari Singh

    2017-10-11

    Wearable electronics is expected to be one of the most active research areas in the next decade; therefore, nanomaterials possessing high carrier mobility, optical transparency, mechanical robustness and flexibility, lightweight, and environmental stability will be in immense demand. Graphene is one of the nanomaterials that fulfill all these requirements, along with other inherently unique properties and convenience to fabricate into different morphological nanostructures, from atomically thin single layers to nanoribbons. Graphene-based materials have also been investigated in sensor technologies, from chemical sensing to detection of cancer biomarkers. The progress of graphene-based flexible gas and chemical sensors in terms of material preparation, sensor fabrication, and their performance are reviewed here. The article provides a brief introduction to graphene-based materials and their potential applications in flexible and stretchable wearable electronic devices. The role of graphene in fabricating flexible gas sensors for the detection of various hazardous gases, including nitrogen dioxide (NO 2 ), ammonia (NH 3 ), hydrogen (H 2 ), hydrogen sulfide (H 2 S), carbon dioxide (CO 2 ), sulfur dioxide (SO 2 ), and humidity in wearable technology, is discussed. In addition, applications of graphene-based materials are also summarized in detecting toxic heavy metal ions (Cd, Hg, Pb, Cr, Fe, Ni, Co, Cu, Ag), and volatile organic compounds (VOCs) including nitrobenzene, toluene, acetone, formaldehyde, amines, phenols, bisphenol A (BPA), explosives, chemical warfare agents, and environmental pollutants. The sensitivity, selectivity and strategies for excluding interferents are also discussed for graphene-based gas and chemical sensors. The challenges for developing future generation of flexible and stretchable sensors for wearable technology that would be usable for the Internet of Things (IoT) are also highlighted.

  3. Novel Magnetic and Chemical Micro Sensors for In-situ, Real-time, and Unattended Use

    International Nuclear Information System (INIS)

    Datskou, I.

    2001-01-01

    There exists a need to develop novel, advanced, unattended magnetic and chemical micro-sensor systems for successful detection, localization, classification and tracking of ground time critical targets of interest. Consistent with the underlying long-term objectives of the development of unattended ground sensors (UGS) program they have investigated the use of a new planted ground sensor platform based on Micro-Electro-Mechanical Systems (MEMS) that can offer magnetic, chemical and possibly acoustic detection. The envisioned micro-system will be low-power and low-cost and will be built around a single type of microstructure element integrating a monolithic optical system and electronics package. This micro sensor can also incorporate burst telemetry to transmit the information, a renewable power source and will be capable of operating under field conditions, with sufficient sensitivity to permit high detection rates, and with sufficient chemical selectivity to prevent high false alarm rates. Preliminary studies, initial designs, and key predicted performance parameters will be presented. Possible applications of such a system include sensitive perimeter monitoring such as minefields and military/nuclear bases, vehicle detection, and aircraft navigation systems, and drug enforcement operations. The results of the present work demonstrate that the microcalorimetric spectroscopy technique can be applied to detect and identify chemicals in the ppm level and the studied microcantilever-based magnetometer can provide sensitivities in the order of 1(micro)T

  4. Progress in triboluminescence-based smart optical sensor system

    International Nuclear Information System (INIS)

    Olawale, David O.; Dickens, Tarik; Sullivan, William G.; Okoli, Okenwa I.; Sobanjo, John O.; Wang, Ben

    2011-01-01

    Extensive research work has been done in recent times to apply the triboluminescence (TL) phenomenon for damage detection in engineering structures. Of particular note are the various attempts to apply it in the detection of impact damages in composites and aerospace structures. This is because TL-based sensor systems have a great potential for wireless, in-situ and distributed (WID) structural health monitoring when fully developed. This review article highlights development and the current state-of-the-art in the application of TL-based sensor systems. The underlying mechanisms believed to be responsible for triboluminescence, particularly in zinc sulfide manganese, a highly triboluminescent material, are discussed. The challenges militating against the full exploitation and field application of TL sensor systems are also identified. Finally, viable solutions and approaches to address these challenges are enumerated. - Highlights: → The underlying mechanisms believed to be responsible for triboluminescence. → State-of-the-art in the development and application of TL-based sensor systems. → The challenges militating against the full exploitation and field application of TL sensor systems are identified. → Viable solutions and approaches to address these challenges are enumerated.

  5. Combination of Tls Point Clouds and 3d Data from Kinect v2 Sensor to Complete Indoor Models

    Science.gov (United States)

    Lachat, E.; Landes, T.; Grussenmeyer, P.

    2016-06-01

    The combination of data coming from multiple sensors is more and more applied for remote sensing issues (multi-sensor imagery) but also in cultural heritage or robotics, since it often results in increased robustness and accuracy of the final data. In this paper, the reconstruction of building elements such as window frames or door jambs scanned thanks to a low cost 3D sensor (Kinect v2) is presented. Their combination within a global point cloud of an indoor scene acquired with a terrestrial laser scanner (TLS) is considered. If the added elements acquired with the Kinect sensor enable to reach a better level of detail of the final model, an adapted acquisition protocol may also provide several benefits as for example time gain. The paper aims at analyzing whether the two measurement techniques can be complementary in this context. The limitations encountered during the acquisition and reconstruction steps are also investigated.

  6. COMBINATION OF TLS POINT CLOUDS AND 3D DATA FROM KINECT V2 SENSOR TO COMPLETE INDOOR MODELS

    Directory of Open Access Journals (Sweden)

    E. Lachat

    2016-06-01

    Full Text Available The combination of data coming from multiple sensors is more and more applied for remote sensing issues (multi-sensor imagery but also in cultural heritage or robotics, since it often results in increased robustness and accuracy of the final data. In this paper, the reconstruction of building elements such as window frames or door jambs scanned thanks to a low cost 3D sensor (Kinect v2 is presented. Their combination within a global point cloud of an indoor scene acquired with a terrestrial laser scanner (TLS is considered. If the added elements acquired with the Kinect sensor enable to reach a better level of detail of the final model, an adapted acquisition protocol may also provide several benefits as for example time gain. The paper aims at analyzing whether the two measurement techniques can be complementary in this context. The limitations encountered during the acquisition and reconstruction steps are also investigated.

  7. Flexible, highly sensitive pressure sensor with a wide range based on graphene-silk network structure

    Science.gov (United States)

    Liu, Ying; Tao, Lu-Qi; Wang, Dan-Yang; Zhang, Tian-Yu; Yang, Yi; Ren, Tian-Ling

    2017-03-01

    In this paper, a flexible, simple-preparation, and low-cost graphene-silk pressure sensor based on soft silk substrate through thermal reduction was demonstrated. Taking silk as the support body, the device had formed a three-dimensional structure with ordered multi-layer structure. Through a simple and low-cost process technology, graphene-silk pressure sensor can achieve the sensitivity value of 0.4 kPa - 1 , and the measurement range can be as high as 140 kPa. Besides, pressure sensor can have a good combination with knitted clothing and textile product. The signal had good reproducibility in response to different pressures. Furthermore, graphene-silk pressure sensor can not only detect pressure higher than 100 kPa, but also can measure weak body signals. The characteristics of high-sensitivity, good repeatability, flexibility, and comfort for skin provide the high possibility to fit on various wearable electronics.

  8. Simulation of novel intensity modulated cascaded coated LPFG sensor based on PMTP

    Science.gov (United States)

    Feng, Wenbin; Gu, Zhengtian; Lin, Qiang; Sang, Jiangang

    2017-12-01

    This paper presents a novel intensity modulated cascaded long-period fiber grating (CLPFG) sensor which is cascaded by two same coated long-period fiber gratings (LPFGs) operating at the phase-matching turning point (PMTP). The sensor combines the high sensitivity of LPFG operating at PMTP and the narrow bandwidth of interference attenuation band of CLPFG, so a higher response to small change of the surrounding refractive index (SRI) can be obtained by intensity modulation. Based on the coupled-mode theory, the grating parameters of the PMTP of a middle odd order cladding mode of a single LPFG are calculated. Then this two same LPFGs are cascaded into a CLPFG, and the optical transmission spectrum of the CLPFG is calculated by transfer matrix method. A resonant wavelength of a special interference attenuation band whose intensity has the highest response to SRI, is selected form CLPFG’s spectrum, and setting the resonant wavelength as the operating wavelength of the sensor. Furthermore, the simulation results show that the resolution of SRI of this CLPFG is available to 1.97 × 10-9 by optimizing the film optical parameters, which is about three orders of magnitude higher than coated dual-peak LPFG and cascaded LPFG sensors. It is noteworthy that the sensor is also sensitive to the refractive index of coat, so that the sensor is expected to be applied to detections of gas, PH value, humidity and so on, in the future.

  9. Applying Sensor-Based Technology to Improve Construction Safety Management.

    Science.gov (United States)

    Zhang, Mingyuan; Cao, Tianzhuo; Zhao, Xuefeng

    2017-08-11

    Construction sites are dynamic and complicated systems. The movement and interaction of people, goods and energy make construction safety management extremely difficult. Due to the ever-increasing amount of information, traditional construction safety management has operated under difficult circumstances. As an effective way to collect, identify and process information, sensor-based technology is deemed to provide new generation of methods for advancing construction safety management. It makes the real-time construction safety management with high efficiency and accuracy a reality and provides a solid foundation for facilitating its modernization, and informatization. Nowadays, various sensor-based technologies have been adopted for construction safety management, including locating sensor-based technology, vision-based sensing and wireless sensor networks. This paper provides a systematic and comprehensive review of previous studies in this field to acknowledge useful findings, identify the research gaps and point out future research directions.

  10. Enhanced refractive index sensor using a combination of a long period fiber grating and a small core singlemode fiber structure

    International Nuclear Information System (INIS)

    Wu, Qiang; Ma, Youqiao; Yang, Minwei; Semenova, Yuliya; Wang, Pengfei; Farrell, Gerald; Chan, Hai Ping; Yuan, Jinhui; Yan, Binbin; Yu, Chongxiu

    2013-01-01

    An enhanced refractive index (RI) sensor based on a combination of a long period fiber grating (LPG) and a small core singlemode fiber (SCSMF) structure is proposed and developed. Since the LPG and SCSMF transmission spectra experience a blue and a red shift respectively as the surrounding RI (SRI) increases, the sensitivity is improved by measuring the separation between the resonant wavelengths of the LPG and SCSMF structures. Experimental results show that the sensor has a sensitivity of 1028 nm/SRI unit in the SRI range from 1.422 to 1.429, which is higher than individual sensitivities of either structure alone used in the experiment. Experimental results agree well with simulation results. (paper)

  11. Design of power cable grounding wire anti-theft monitoring system

    Science.gov (United States)

    An, Xisheng; Lu, Peng; Wei, Niansheng; Hong, Gang

    2018-01-01

    In order to prevent the serious consequences of the power grid failure caused by the power cable grounding wire theft, this paper presents a GPRS based power cable grounding wire anti-theft monitoring device system, which includes a camera module, a sensor module, a micro processing system module, and a data monitoring center module, a mobile terminal module. Our design utilize two kinds of methods for detecting and reporting comprehensive image, it can effectively solve the problem of power and cable grounding wire box theft problem, timely follow-up grounded cable theft events, prevent the occurrence of electric field of high voltage transmission line fault, improve the reliability of the safe operation of power grid.

  12. Low Working-Temperature Acetone Vapor Sensor Based on Zinc Nitride and Oxide Hybrid Composites.

    Science.gov (United States)

    Qu, Fengdong; Yuan, Yao; Guarecuco, Rohiverth; Yang, Minghui

    2016-06-01

    Transition-metal nitride and oxide composites are a significant class of emerging materials that have attracted great interest for their potential in combining the advantages of nitrides and oxides. Here, a novel class of gas sensing materials based on hybrid Zn3 N2 and ZnO composites is presented. The Zn3 N2 /ZnO (ZnNO) composites-based sensor exhibits selectivity and high sensitivity toward acetone vapor, and the sensitivity is dependent on the nitrogen content of the composites. The ZnNO-11.7 described herein possesses a low working temperature of 200 °C. The detection limit (0.07 ppm) is below the diabetes diagnosis threshold (1.8 ppm). In addition, the sensor shows high reproducibility and long-term stability. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Sensor equipment of the German earth scientific airplane program

    Science.gov (United States)

    Seige, P.

    1975-01-01

    The German airplane program for earth scientific research supports the work of a vast staff of earth scientists from universities and federal agencies. Due to their fields of interest, which are in oceanography, hydrology, geology, ecology, and forestry, five test areas were selected which are spread all over Germany. The sensor package, which was designed in accordance with the requirements of this group of scientists, will be installed in a DO 28 D2 type airplane. The sensor equipment consists of a series of 70-mm cameras having different film/filter combinations, a photogrammetric camera, an infrared radiometer, an 11-channel multispectral line scanner, a LANDSAT-compatible radiometer, and a complex avionic system. Along with the airplane, a truck will be equipped with a set of radiometers and other sensor devices for extensive ground-truth measurement; this also includes a cherry picker.

  14. CoCMA: Energy-Efficient Coverage Control in Cluster-Based Wireless Sensor Networks Using a Memetic Algorithm

    Directory of Open Access Journals (Sweden)

    Yung-Chung Wang

    2009-06-01

    Full Text Available Deployment of wireless sensor networks (WSNs has drawn much attention in recent years. Given the limited energy for sensor nodes, it is critical to implement WSNs with energy efficiency designs. Sensing coverage in networks, on the other hand, may degrade gradually over time after WSNs are activated. For mission-critical applications, therefore, energy-efficient coverage control should be taken into consideration to support the quality of service (QoS of WSNs. Usually, coverage-controlling strategies present some challenging problems: (1 resolving the conflicts while determining which nodes should be turned off to conserve energy; (2 designing an optimal wake-up scheme that avoids awakening more nodes than necessary. In this paper, we implement an energy-efficient coverage control in cluster-based WSNs using a Memetic Algorithm (MA-based approach, entitled CoCMA, to resolve the challenging problems. The CoCMA contains two optimization strategies: a MA-based schedule for sensor nodes and a wake-up scheme, which are responsible to prolong the network lifetime while maintaining coverage preservation. The MA-based schedule is applied to a given WSN to avoid unnecessary energy consumption caused by the redundant nodes. During the network operation, the wake-up scheme awakens sleeping sensor nodes to recover coverage hole caused by dead nodes. The performance evaluation of the proposed CoCMA was conducted on a cluster-based WSN (CWSN under either a random or a uniform deployment of sensor nodes. Simulation results show that the performance yielded by the combination of MA and wake-up scheme is better than that in some existing approaches. Furthermore, CoCMA is able to activate fewer sensor nodes to monitor the required sensing area.

  15. Adaptive Multi-Sensor Perception for Driving Automation in Outdoor Contexts

    Directory of Open Access Journals (Sweden)

    Annalisa Milella

    2014-08-01

    Full Text Available In this research, adaptive perception for driving automation is discussed so as to enable a vehicle to automatically detect driveable areas and obstacles in the scene. It is especially designed for outdoor contexts where conventional perception systems that rely on a priori knowledge of the terrain's geometric properties, appearance properties, or both, is prone to fail, due to the variability in the terrain properties and environmental conditions. In contrast, the proposed framework uses a self-learning approach to build a model of the ground class that is continuously adjusted online to reflect the latest ground appearance. The system also features high flexibility, as it can work using a single sensor modality or a multi-sensor combination. In the context of this research, different embodiments have been demonstrated using range data coming from either a radar or a stereo camera, and adopting self-supervised strategies where monocular vision is automatically trained by radar or stereo vision. A comprehensive set of experimental results, obtained with different ground vehicles operating in the field, are presented to validate and assess the performance of the system.

  16. Optimization of systems with the combination of ground-source heat pump and solar collectors in dwellings

    DEFF Research Database (Denmark)

    Kjellsson, Elisabeth; Hellström, Göran; Perers, Bengt

    2010-01-01

    The use of ground-source heat pumps for heating and domestic hot water in dwellings is common in Sweden. The combination with solar collectors has been introduced to reduce the electricity demand in the system. In order to analyze different systems with combinations of solar collectors and ground......-source heat pumps, computer simulations have been carried out with the simulation program TRNSYS. Large differences were found between the system alternatives. The optimal design is when solar heat produces domestic hot water during summertime and recharges the borehole during wintertime. The advantage...... is related to the rate of heat extraction from the borehole as well as the overall design of the system. The demand of electricity may increase with solar recharging, because of the increased operating time of the circulation pumps. Another advantage with solar heat in combination with heat pumps is when...

  17. Development of GaN-based micro chemical sensor nodes

    Science.gov (United States)

    Son, Kyung-ah; Prokopuk, Nicholas; George, Thomas; Moon, Jeong S.

    2005-01-01

    Sensors based on III-N technology are gaining significant interest due to their potential for monolithic integration of RF transceivers and light sources and the capability of high temperature operations. We are developing a GaN-based micro chemical sensor node for remote detection of chemical toxins, and present electrical responses of AlGaN/GaN HEMT (High Electron Mobility Transistor) sensors to chemical toxins as well as other common gases.

  18. Optimize Etching Based Single Mode Fiber Optic Temperature Sensor

    OpenAIRE

    Ajay Kumar; Dr. Pramod Kumar

    2014-01-01

    This paper presents a description of etching process for fabrication single mode optical fiber sensors. The process of fabrication demonstrates an optimized etching based method to fabricate single mode fiber (SMF) optic sensors in specified constant time and temperature. We propose a single mode optical fiber based temperature sensor, where the temperature sensing region is obtained by etching its cladding diameter over small length to a critical value. It is observed that th...

  19. Motion Artifact Quantification and Sensor Fusion for Unobtrusive Health Monitoring.

    Science.gov (United States)

    Hoog Antink, Christoph; Schulz, Florian; Leonhardt, Steffen; Walter, Marian

    2017-12-25

    Sensors integrated into objects of everyday life potentially allow unobtrusive health monitoring at home. However, since the coupling of sensors and subject is not as well-defined as compared to a clinical setting, the signal quality is much more variable and can be disturbed significantly by motion artifacts. One way of tackling this challenge is the combined evaluation of multiple channels via sensor fusion. For robust and accurate sensor fusion, analyzing the influence of motion on different modalities is crucial. In this work, a multimodal sensor setup integrated into an armchair is presented that combines capacitively coupled electrocardiography, reflective photoplethysmography, two high-frequency impedance sensors and two types of ballistocardiography sensors. To quantify motion artifacts, a motion protocol performed by healthy volunteers is recorded with a motion capture system, and reference sensors perform cardiorespiratory monitoring. The shape-based signal-to-noise ratio SNR S is introduced and used to quantify the effect on motion on different sensing modalities. Based on this analysis, an optimal combination of sensors and fusion methodology is developed and evaluated. Using the proposed approach, beat-to-beat heart-rate is estimated with a coverage of 99.5% and a mean absolute error of 7.9 ms on 425 min of data from seven volunteers in a proof-of-concept measurement scenario.

  20. A high sensitivity nanomaterial based SAW humidity sensor

    Energy Technology Data Exchange (ETDEWEB)

    Wu, T-T; Chou, T-H [Institute of Applied Mechanics, National Taiwan University, Taipei 106, Taiwan (China); Chen, Y-Y [Department of Mechanical Engineering, Tatung University, Taipei 104, Taiwan (China)], E-mail: wutt@ndt.iam.ntu.edu.tw

    2008-04-21

    In this paper, a highly sensitive humidity sensor is reported. The humidity sensor is configured by a 128{sup 0}YX-LiNbO{sub 3} based surface acoustic wave (SAW) resonator whose operating frequency is at 145 MHz. A dual delay line configuration is realized to eliminate external temperature fluctuations. Moreover, for nanostructured materials possessing high surface-to-volume ratio, large penetration depth and fast charge diffusion rate, camphor sulfonic acid doped polyaniline (PANI) nanofibres are synthesized by the interfacial polymerization method and further deposited on the SAW resonator as selective coating to enhance sensitivity. The humidity sensor is used to measure various relative humidities in the range 5-90% at room temperature. Results show that the PANI nanofibre based SAW humidity sensor exhibits excellent sensitivity and short-term repeatability.

  1. pH sensor based on boron nitride nanotubes.

    Science.gov (United States)

    Huang, Q; Bando, Y; Zhao, L; Zhi, C Y; Golberg, D

    2009-10-14

    A submicrometer-sized pH sensor based on biotin-fluorescein-functionalized multiwalled BN nanotubes with anchored Ag nanoparticles is designed. Intrinsic pH-dependent photoluminescence and Raman signals in attached fluorescein molecules enhanced by Ag nanoparticles allow this novel nanohybrid to perform as a practical pH sensor. It is able to work in a submicrometer-sized space. For example, the sensor may determine the environmental pH of sub-units in living cells where a traditional optical fiber sensor fails because of spatial limitations.

  2. pH sensor based on boron nitride nanotubes

    International Nuclear Information System (INIS)

    Huang, Q; Bando, Y; Zhao, L; Zhi, C Y; Golberg, D

    2009-01-01

    A submicrometer-sized pH sensor based on biotin-fluorescein-functionalized multiwalled BN nanotubes with anchored Ag nanoparticles is designed. Intrinsic pH-dependent photoluminescence and Raman signals in attached fluorescein molecules enhanced by Ag nanoparticles allow this novel nanohybrid to perform as a practical pH sensor. It is able to work in a submicrometer-sized space. For example, the sensor may determine the environmental pH of sub-units in living cells where a traditional optical fiber sensor fails because of spatial limitations.

  3. Physiological roles of acid-base sensors.

    Science.gov (United States)

    Levin, Lonny R; Buck, Jochen

    2015-01-01

    Acid-base homeostasis is essential for life. The macromolecules upon which living organisms depend are sensitive to pH changes, and physiological systems use the equilibrium between carbon dioxide, bicarbonate, and protons to buffer their pH. Biological processes and environmental insults are constantly challenging an organism's pH; therefore, to maintain a consistent and proper pH, organisms need sensors that measure pH and that elicit appropriate responses. Mammals use multiple sensors for measuring both intracellular and extracellular pH, and although some mammalian pH sensors directly measure protons, it has recently become apparent that many pH-sensing systems measure pH via bicarbonate-sensing soluble adenylyl cyclase.

  4. Use of a mobile phone for potentiostatic control with low cost paper-based microfluidic sensors

    Energy Technology Data Exchange (ETDEWEB)

    Delaney, Jacqui L.; Doeven, Egan H.; Harsant, Anthony J.; Hogan, Conor F., E-mail: c.hogan@latrobe.edu.au

    2013-08-06

    Graphical abstract: -- Highlights: •The ability to generate ECL emission using the audio output of a mobile phone is demonstrated. •Electrochemical control can be achieved by controlling the amplitude and waveform of the sound. •A mobile phone “app” synchronises the electrochemical stimulation with detection via the camera. •In combination with paper-based microfluidic sensors, extremely low cost analysis is possible. •Detection of proline at levels suitable for diagnosis of hyperprolinemia is demonstrated. -- Abstract: By exploiting its ability to play sounds, a mobile phone with suitable software installed can serve the basic functions of a potentiostat in controlling an applied potential to oxidise ECL-active molecules, while the resultant photonic signal is monitored using the camera in video mode. In combination with paper microfluidic sensors this opens significant new possibilities for low-cost, instrument-free sensing.

  5. Use of a mobile phone for potentiostatic control with low cost paper-based microfluidic sensors

    International Nuclear Information System (INIS)

    Delaney, Jacqui L.; Doeven, Egan H.; Harsant, Anthony J.; Hogan, Conor F.

    2013-01-01

    Graphical abstract: -- Highlights: •The ability to generate ECL emission using the audio output of a mobile phone is demonstrated. •Electrochemical control can be achieved by controlling the amplitude and waveform of the sound. •A mobile phone “app” synchronises the electrochemical stimulation with detection via the camera. •In combination with paper-based microfluidic sensors, extremely low cost analysis is possible. •Detection of proline at levels suitable for diagnosis of hyperprolinemia is demonstrated. -- Abstract: By exploiting its ability to play sounds, a mobile phone with suitable software installed can serve the basic functions of a potentiostat in controlling an applied potential to oxidise ECL-active molecules, while the resultant photonic signal is monitored using the camera in video mode. In combination with paper microfluidic sensors this opens significant new possibilities for low-cost, instrument-free sensing

  6. Intelligent error correction method applied on an active pixel sensor based star tracker

    Science.gov (United States)

    Schmidt, Uwe

    2005-10-01

    Star trackers are opto-electronic sensors used on-board of satellites for the autonomous inertial attitude determination. During the last years star trackers became more and more important in the field of the attitude and orbit control system (AOCS) sensors. High performance star trackers are based up today on charge coupled device (CCD) optical camera heads. The active pixel sensor (APS) technology, introduced in the early 90-ties, allows now the beneficial replacement of CCD detectors by APS detectors with respect to performance, reliability, power, mass and cost. The company's heritage in star tracker design started in the early 80-ties with the launch of the worldwide first fully autonomous star tracker system ASTRO1 to the Russian MIR space station. Jena-Optronik recently developed an active pixel sensor based autonomous star tracker "ASTRO APS" as successor of the CCD based star tracker product series ASTRO1, ASTRO5, ASTRO10 and ASTRO15. Key features of the APS detector technology are, a true xy-address random access, the multiple windowing read out and the on-chip signal processing including the analogue to digital conversion. These features can be used for robust star tracking at high slew rates and under worse conditions like stray light and solar flare induced single event upsets. A special algorithm have been developed to manage the typical APS detector error contributors like fixed pattern noise (FPN), dark signal non-uniformity (DSNU) and white spots. The algorithm works fully autonomous and adapts to e.g. increasing DSNU and up-coming white spots automatically without ground maintenance or re-calibration. In contrast to conventional correction methods the described algorithm does not need calibration data memory like full image sized calibration data sets. The application of the presented algorithm managing the typical APS detector error contributors is a key element for the design of star trackers for long term satellite applications like

  7. Data fusion for target tracking and classification with wireless sensor network

    Science.gov (United States)

    Pannetier, Benjamin; Doumerc, Robin; Moras, Julien; Dezert, Jean; Canevet, Loic

    2016-10-01

    In this paper, we address the problem of multiple ground target tracking and classification with information obtained from a unattended wireless sensor network. A multiple target tracking (MTT) algorithm, taking into account road and vegetation information, is proposed based on a centralized architecture. One of the key issue is how to adapt classical MTT approach to satisfy embedded processing. Based on track statistics, the classification algorithm uses estimated location, velocity and acceleration to help to classify targets. The algorithms enables tracking human and vehicles driving both on and off road. We integrate road or trail width and vegetation cover, as constraints in target motion models to improve performance of tracking under constraint with classification fusion. Our algorithm also presents different dynamic models, to palliate the maneuvers of targets. The tracking and classification algorithms are integrated into an operational platform (the fusion node). In order to handle realistic ground target tracking scenarios, we use an autonomous smart computer deposited in the surveillance area. After the calibration step of the heterogeneous sensor network, our system is able to handle real data from a wireless ground sensor network. The performance of system is evaluated in a real exercise for intelligence operation ("hunter hunt" scenario).

  8. Compression and Combining Based on Channel Shortening and Rank Reduction Technique for Cooperative Wireless Sensor Networks

    KAUST Repository

    Ahmed, Qasim Zeeshan

    2013-12-18

    This paper investigates and compares the performance of wireless sensor networks where sensors operate on the principles of cooperative communications. We consider a scenario where the source transmits signals to the destination with the help of L sensors. As the destination has the capacity of processing only U out of these L signals, the strongest U signals are selected while the remaining (L?U) signals are suppressed. A preprocessing block similar to channel-shortening is proposed in this contribution. However, this preprocessing block employs a rank-reduction technique instead of channel-shortening. By employing this preprocessing, we are able to decrease the computational complexity of the system without affecting the bit error rate (BER) performance. From our simulations, it can be shown that these schemes outperform the channel-shortening schemes in terms of computational complexity. In addition, the proposed schemes have a superior BER performance as compared to channel-shortening schemes when sensors employ fixed gain amplification. However, for sensors which employ variable gain amplification, a tradeoff exists in terms of BER performance between the channel-shortening and these schemes. These schemes outperform channel-shortening scheme for lower signal-to-noise ratio.

  9. Ultra-Low Power Consuming Direct Radiation Sensors Based on Floating Gate Structures

    Directory of Open Access Journals (Sweden)

    Evgeny Pikhay

    2017-07-01

    Full Text Available In this paper, we report on ultra-low power consuming single poly floating gate direct radiation sensors. The developed devices are intended for total ionizing dose (TID measurements and fabricated in a standard CMOS process flow. Sensor design and operation is discussed in detail. Original array sensors were suggested and fabricated that allowed high statistical significance of the radiation measurements and radiation imaging functions. Single sensors and array sensors were analyzed in combination with the specially developed test structures. This allowed insight into the physics of sensor operations and exclusion of the phenomena related to material degradation under irradiation in the interpretation of the measurement results. Response of the developed sensors to various sources of ionizing radiation (Gamma, X-ray, UV, energetic ions was investigated. The optimal design of sensor for implementation in dosimetry systems was suggested. The roadmap for future improvement of sensor performance is suggested.

  10. Monitoring of pipeline deformations using optical fiber sensors based on Bragg lattices; Monitoracao de deformacoes em dutos utilizando sensores a fibra optica com base em redes de Bragg

    Energy Technology Data Exchange (ETDEWEB)

    Moszkowica, Viktor Nigri [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil)]. E-mail: vnigri@bol.com.br

    2002-06-01

    In the petroleum sector there is a growing need for the use of pipelines as well as for their monitoring. A way to avoid leaks that can cause great damage to the environment is by the monitoring of deformations. In case failures can not be avoided through operational procedures, the monitoring of deformations can identify the initial moment and location of the leak, allowing for quick action on the part of the cleaning and depollution teams. Also important is the monitoring of slopes and soil movements. The same thing applies to production and transfer submarine pipelines subject to complex dynamic loadings that combine internal and external pressure, torsion, axial stress and, the most common of all, flexion loading. For this type of application, optical fiber sensors present a number of interesting features. Multiplexing, remote operation and long distance distribution of sensors are characteristics that attract their use in deformation monitoring systems. Presented herein are the research results of works that had the objective of developing deformation monitoring techniques in pipelines using optical fiber sensors based on Bragg grating. The technical feasibility of this technology is demonstrated through laboratorial tests. Also discussed herein are methods for field implementation of sensors, optical signal multiplexing techniques and potential advantages of applying this technology. (author)

  11. Electrochemical sensors and biosensors based on less aggregated graphene.

    Science.gov (United States)

    Bo, Xiangjie; Zhou, Ming; Guo, Liping

    2017-03-15

    As a novel single-atom-thick sheet of sp 2 hybridized carbon atoms, graphene (GR) has attracted extensive attention in recent years because of its unique and remarkable properties, such as excellent electrical conductivity, large theoretical specific surface area, and strong mechanical strength. However, due to the π-π interaction, GR sheets are inclined to stack together, which may seriously degrade the performance of GR with the unique single-atom layer. In recent years, an increasing number of GR-based electrochemical sensors and biosensors are reported, which may reflect that GR has been considered as a kind of hot and promising electrode material for electrochemical sensor and biosensor construction. However, the active sites on GR surface induced by the irreversible GR aggregations would be deeply secluded inside the stacked GR sheets and therefore are not available for the electrocatalysis. So the alleviation or the minimization of the aggregation level for GR sheets would facilitate the exposure of active sites on GR and effectively upgrade the performance of GR-based electrochemical sensors and biosensors. Less aggregated GR with low aggregation and high dispersed structure can be used in improving the electrochemical activity of GR-based electrochemical sensors or biosensors. In this review, we summarize recent advances and new progress for the development of electrochemical sensors based on less aggregated GR. To achieve such goal, many strategies (such as the intercalation of carbon materials, surface modification, and structural engineering) have been applied to alleviate the aggregation level of GR in order to enhance the performance of GR-based electrochemical sensors and biosensors. Finally, the challenges associated with less aggregated GR-based electrochemical sensors and biosensors as well as related future research directions are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. A market-based optimization approach to sensor and resource management

    Science.gov (United States)

    Schrage, Dan; Farnham, Christopher; Gonsalves, Paul G.

    2006-05-01

    Dynamic resource allocation for sensor management is a problem that demands solutions beyond traditional approaches to optimization. Market-based optimization applies solutions from economic theory, particularly game theory, to the resource allocation problem by creating an artificial market for sensor information and computational resources. Intelligent agents are the buyers and sellers in this market, and they represent all the elements of the sensor network, from sensors to sensor platforms to computational resources. These agents interact based on a negotiation mechanism that determines their bidding strategies. This negotiation mechanism and the agents' bidding strategies are based on game theory, and they are designed so that the aggregate result of the multi-agent negotiation process is a market in competitive equilibrium, which guarantees an optimal allocation of resources throughout the sensor network. This paper makes two contributions to the field of market-based optimization: First, we develop a market protocol to handle heterogeneous goods in a dynamic setting. Second, we develop arbitrage agents to improve the efficiency in the market in light of its dynamic nature.

  13. Influence of temperature and humidity on carbon based printed flexible sensors

    KAUST Repository

    Nag, Anindya

    2018-03-02

    This paper presents the response of two different types of novel printed sensors towards the change in temperature and humidity. The electrodes of all the sensors were based on carbon materials. Followed by the design and fabrication of the sensors, the responses of the sensors were analyzed for different temperature and humidity conditions in an incubator. These results provide a podium to enhance the alternation of the fabrication procedure of carbon-based printed sensors.

  14. Influence of temperature and humidity on carbon based printed flexible sensors

    KAUST Repository

    Nag, Anindya; Mukhopadhyay, Subhas; Kosel, Jü rgen

    2018-01-01

    This paper presents the response of two different types of novel printed sensors towards the change in temperature and humidity. The electrodes of all the sensors were based on carbon materials. Followed by the design and fabrication of the sensors, the responses of the sensors were analyzed for different temperature and humidity conditions in an incubator. These results provide a podium to enhance the alternation of the fabrication procedure of carbon-based printed sensors.

  15. Molecular Imprinting Technology in Quartz Crystal Microbalance (QCM) Sensors

    Science.gov (United States)

    Emir Diltemiz, Sibel; Keçili, Rüstem; Ersöz, Arzu; Say, Rıdvan

    2017-01-01

    Molecularly imprinted polymers (MIPs) as artificial antibodies have received considerable scientific attention in the past years in the field of (bio)sensors since they have unique features that distinguish them from natural antibodies such as robustness, multiple binding sites, low cost, facile preparation and high stability under extreme operation conditions (higher pH and temperature values, etc.). On the other hand, the Quartz Crystal Microbalance (QCM) is an analytical tool based on the measurement of small mass changes on the sensor surface. QCM sensors are practical and convenient monitoring tools because of their specificity, sensitivity, high accuracy, stability and reproducibility. QCM devices are highly suitable for converting the recognition process achieved using MIP-based memories into a sensor signal. Therefore, the combination of a QCM and MIPs as synthetic receptors enhances the sensitivity through MIP process-based multiplexed binding sites using size, 3D-shape and chemical function having molecular memories of the prepared sensor system toward the target compound to be detected. This review aims to highlight and summarize the recent progress and studies in the field of (bio)sensor systems based on QCMs combined with molecular imprinting technology. PMID:28245588

  16. Hydrogeology, simulated ground-water flow, and ground-water quality, Wright-Patterson Air Force Base, Ohio

    Science.gov (United States)

    Dumouchelle, D.H.; Schalk, C.W.; Rowe, G.L.; De Roche, J.T.

    1993-01-01

    Ground water is the primary source of water in the Wright-Patterson Air Force Base area. The aquifer consists of glacial sands and gravels that fill a buried bedrock-valley system. Consolidated rocks in the area consist of poorly permeable Ordovician shale of the Richmondian stage, in the upland areas, the Brassfield Limestone of Silurian age. The valleys are filled with glacial sediments of Wisconsinan age consisting of clay-rich tills and coarse-grained outwash deposits. Estimates of hydraulic conductivity of the shales based on results of displacement/recovery tests range from 0.0016 to 12 feet per day; estimates for the glacial sediments range from less than 1 foot per day to more than 1,000 feet per day. Ground water flow from the uplands towards the valleys and the major rivers in the region, the Great Miami and the Mad Rivers. Hydraulic-head data indicate that ground water flows between the bedrock and unconsolidated deposits. Data from a gain/loss study of the Mad River System and hydrographs from nearby wells reveal that the reach of the river next to Wright-Patterson Air Force Base is a ground-water discharge area. A steady-state, three-dimensional ground-water-flow model was developed to simulate ground-water flow in the region. The model contains three layers and encompasses about 100 square miles centered on Wright-Patterson Air Force Base. Ground water enters the modeled area primarily by river leakage and underflow at the model boundary. Ground water exits the modeled area primarily by flow through the valleys at the model boundaries and through production wells. A model sensitivity analysis involving systematic changes in values of hydrologic parameters in the model indicates that the model is most sensitive to decreases in riverbed conductance and vertical conductance between the upper two layers. The analysis also indicates that the contribution of water to the buried-valley aquifer from the bedrock that forms the valley walls is about 2 to 4

  17. A performance study of unmanned aerial vehicle-based sensor networks under cyber attack

    Science.gov (United States)

    Puchaty, Ethan M.

    In UAV-based sensor networks, an emerging area of interest is the performance of these networks under cyber attack. This study seeks to evaluate the performance trade-offs from a System-of-Systems (SoS) perspective between various UAV communications architecture options in the context two missions: tracking ballistic missiles and tracking insurgents. An agent-based discrete event simulation is used to model a sensor communication network consisting of UAVs, military communications satellites, ground relay stations, and a mission control center. Network susceptibility to cyber attack is modeled with probabilistic failures and induced data variability, with performance metrics focusing on information availability, latency, and trustworthiness. Results demonstrated that using UAVs as routers increased network availability with a minimal latency penalty and communications satellite networks were best for long distance operations. Redundancy in the number of links between communication nodes helped mitigate cyber-caused link failures and add robustness in cases of induced data variability by an adversary. However, when failures were not independent, redundancy and UAV routing were detrimental in some cases to network performance. Sensitivity studies indicated that long cyber-caused downtimes and increasing failure dependencies resulted in build-ups of failures and caused significant degradations in network performance.

  18. Modal-pushover-based ground-motion scaling procedure

    Science.gov (United States)

    Kalkan, Erol; Chopra, Anil K.

    2011-01-01

    Earthquake engineering is increasingly using nonlinear response history analysis (RHA) to demonstrate the performance of structures. This rigorous method of analysis requires selection and scaling of ground motions appropriate to design hazard levels. This paper presents a modal-pushover-based scaling (MPS) procedure to scale ground motions for use in a nonlinear RHA of buildings. In the MPS method, the ground motions are scaled to match to a specified tolerance, a target value of the inelastic deformation of the first-mode inelastic single-degree-of-freedom (SDF) system whose properties are determined by the first-mode pushover analysis. Appropriate for first-mode dominated structures, this approach is extended for structures with significant contributions of higher modes by considering elastic deformation of second-mode SDF systems in selecting a subset of the scaled ground motions. Based on results presented for three actual buildings-4, 6, and 13-story-the accuracy and efficiency of the MPS procedure are established and its superiority over the ASCE/SEI 7-05 scaling procedure is demonstrated.

  19. A low cost and pipe conformable microwave-based water-cut sensor

    KAUST Repository

    Karimi, Muhammad Akram

    2016-08-15

    Efficient oil production and refining processes require the precise measurement of water content in oil (i.e., water-cut [WC]) which is extracted during oil production as a by-product. Traditional laboratory water fraction measurements are precise but incapable of providing real-time information, while recently reported inline WC measurements are either incapable of sensing the full WC range (0-100%), restricted to a limited selection of pipe sizes, bulky, intrusive or extremely expensive. This work presents a novel planar microwave sensor for entirely non-intrusive in situ WC sensing over the full range of operation. Its planar configuration has enabled the direct implementation of this sensor on the pipe surface using two low cost methods i.e. copper tape and 3D printed mask. The innovative ground plane design makes this WC sensor usable for the wide range of pipe sizes present in the oil industry. The viability of this sensor has been confirmed through EM simulations as well as through characterization of two types of prototype. The proposed design offers very fine resolution due to its wide sensing range (>110%) in the frequency band of 90-190MHz and repeatability of 0.1%.

  20. Figure and Ground in the Visual Cortex: V2 Combines Stereoscopic Cues with Gestalt Rules

    OpenAIRE

    Qiu, Fangtu T.; von der Heydt, Rüdiger

    2005-01-01

    Figure-ground organization is a process by which the visual system identifies some image regions as foreground and others as background, inferring three-dimensional (3D) layout from 2D displays. A recent study reported that edge responses of neurons in area V2 are selective for side-of-figure, suggesting that figure-ground organization is encoded in the contour signals (border-ownership coding). Here we show that area V2 combines two strategies of computation, one that exploits binocular ster...

  1. Flexible textile-based strain sensor induced by contacts

    International Nuclear Information System (INIS)

    Zhang, Hui

    2015-01-01

    In this paper, the contact effects are used as the key sensing element to develop flexible textile-structured strain sensors. The structures of the contact are analyzed theoretically and the contact resistances are investigated experimentally. The electromechanical properties of the textiles are investigated to find the key factors which determine the sensitivity, repeatability, and linearity of the sensor. The sensing mechanism is based on the change of contact resistance induced by the change of the configuration of the textiles. In order to improve the performance of the textile strain sensor, the contact resistance is designed based on the electromechanical properties of the fabric. It can be seen from the results that the performance of the sensor is largely affected by the structure of the contacts, which are determined by the morphology of fiber surface and the structures of the yarn and fabric. (paper)

  2. IBE-Lite: a lightweight identity-based cryptography for body sensor networks.

    Science.gov (United States)

    Tan, Chiu C; Wang, Haodong; Zhong, Sheng; Li, Qun

    2009-11-01

    A body sensor network (BSN) is a network of sensors deployed on a person's body for health care monitoring. Since the sensors collect personal medical data, security and privacy are important components in a BSN. In this paper, we developed IBE-Lite, a lightweight identity-based encryption suitable for sensors in a BSN. We present protocols based on IBE-Lite that balance security and privacy with accessibility and perform evaluation using experiments conducted on commercially available sensors.

  3. Bulk disk resonator based ultrasensitive mass sensor

    DEFF Research Database (Denmark)

    Cagliani, Alberto; Davis, Zachary James

    2009-01-01

    range. The sensor has been characterized in terms of sensitivity both for distributed mass detection, performing six consecutive depositions of e-beam evaporated Au, and localized mass detection, depositing approximately 7.5 pg of Pt/Ga/C three times consecutively with a Focused Ion Beam system......In the framework of developing an innovative label-free sensor for multiarrayed biodetection applications, we present a novel bulk resonator based mass sensor. The sensor is a polysilicon disk which shows a Q-factor of 6400 in air at 68.8 MHz, resulting in mass resolutions down in the femtogram....... The sensor has an extremely high distributed mass to frequency shift sensitivity of 60104 Hzcm2/¿g and shows a localized mass to frequency sensitivity up to 4405 Hz/pg with a localized mass resolution down to 15 fg. The device has been fabricated with a new microfabrication process that uses only two...

  4. Feedback-type giant magneto-impedance sensor based on longitudinal excitation

    International Nuclear Information System (INIS)

    Zhao Wen; Bu Xiongzhu; Yu Geliang; Xiang Chao

    2012-01-01

    In this paper, the characteristics of Fe-based amorphous ribbon based on the longitudinal excitation are investigated with assistance of the theory of the giant magneto-impedance (GMI) effect. A feedback-type GMI micro-magnetic sensor is designed with regard to the design of the sensing element, the excitation circuit, the conditional circuit and the feedback circuit. With the analysis of the dynamic and static characteristics of the feedback-type GMI sensor, it is concluded that the designed feedback-type GMI sensor has higher linearity, stability and dynamic characteristics than non-feedback-type GMI sensor in −2.5 to +2.5 Oe. - Highlights: ► A feedback-type GMI micro-magnetic sensor is designed. ► Excitation coil and feedback coil of the sensor is designed to be in one. ► The feedback-type sensor has higher linearity and stability than non-feedback type. ► The feedback-type sensor has better dynamic characteristics than non-feedback type.

  5. Use of Hi-resolution data for evaluating accuracy of traffic volume counts collected by microwave sensors

    Directory of Open Access Journals (Sweden)

    David K. Chang

    2017-10-01

    Full Text Available Over the past few years, the Utah Department of Transportation has developed the signal performance metrics (SPMs system to evaluate the performance of signalized intersections dynamically. This system currently provides data summaries for several performance measures, one of them being turning movement counts collected by microwave sensors. As this system became public, there was a need to evaluate the accuracy of the data placed on the SPMs. A large-scale data collection was carried out to meet this need. Vehicles in the Hi-resolution data from microwave sensors were matched with the vehicles by ground-truth volume count data. Matching vehicles from the microwave sensor data and the ground-truth data manually collected required significant effort. A spreadsheet-based data analysis procedure was developed to carry out the task. A mixed model analysis of variance was used to analyze the effects of the factors considered on turning volume count accuracy. The analysis found that approach volume level and number of approach lanes would have significant effect on the accuracy of turning volume counts but the location of the sensors did not significantly affect the accuracy of turning volume counts. In addition, it was found that the location of lanes in relation to the sensor did not significantly affect the accuracy of lane-by-lane volume counts. This indicated that accuracy analysis could be performed by using total approach volumes without comparing specific turning counts, that is, left-turn, through and right-turn movements. In general, the accuracy of approach volume counts collected by microwave sensors were within the margin of error that traffic engineers could accept. The procedure taken to perform the analysis and a summary of accuracy of volume counts for the factor combinations considered are presented in this paper.

  6. Analyzing the factors affecting network lifetime cluster-based wireless sensor network

    International Nuclear Information System (INIS)

    Malik, A.S.; Qureshi, A.

    2010-01-01

    Cluster-based wireless sensor networks enable the efficient utilization of the limited energy resources of the deployed sensor nodes and hence prolong the node as well as network lifetime. Low Energy Adaptive Clustering Hierarchy (Leach) is one of the most promising clustering protocol proposed for wireless sensor networks. This paper provides the energy utilization and lifetime analysis for cluster-based wireless sensor networks based upon LEACH protocol. Simulation results identify some important factors that induce unbalanced energy utilization between the sensor nodes and hence affect the network lifetime in these types of networks. These results highlight the need for a standardized, adaptive and distributed clustering technique that can increase the network lifetime by further balancing the energy utilization among sensor nodes. (author)

  7. Systematic Review of Real-time Remote Health Monitoring System in Triage and Priority-Based Sensor Technology: Taxonomy, Open Challenges, Motivation and Recommendations.

    Science.gov (United States)

    Albahri, O S; Albahri, A S; Mohammed, K I; Zaidan, A A; Zaidan, B B; Hashim, M; Salman, Omar H

    2018-03-22

    The new and ground-breaking real-time remote monitoring in triage and priority-based sensor technology used in telemedicine have significantly bounded and dispersed communication components. To examine these technologies and provide researchers with a clear vision of this area, we must first be aware of the utilised approaches and existing limitations in this line of research. To this end, an extensive search was conducted to find articles dealing with (a) telemedicine, (b) triage, (c) priority and (d) sensor; (e) comprehensively review related applications and establish the coherent taxonomy of these articles. ScienceDirect, IEEE Xplore and Web of Science databases were checked for articles on triage and priority-based sensor technology in telemedicine. The retrieved articles were filtered according to the type of telemedicine technology explored. A total of 150 articles were selected and classified into two categories. The first category includes reviews and surveys of triage and priority-based sensor technology in telemedicine. The second category includes articles on the three-tiered architecture of telemedicine. Tier 1 represents the users. Sensors acquire the vital signs of the users and send them to Tier 2, which is the personal gateway that uses local area network protocols or wireless body area network. Medical data are sent from Tier 2 to Tier 3, which is the healthcare provider in medical institutes. Then, the motivation for using triage and priority-based sensor technology in telemedicine, the issues related to the obstruction of its application and the development and utilisation of telemedicine are examined on the basis of the findings presented in the literature.

  8. THE GAS SENSORS BASED ON ZINC OXIDE (THE REVIEW)

    OpenAIRE

    Bugayova, M. E.; Koval, V. M.; Lashkarev, G. V.; Lazorenko, V. I.; Karpina, V. A.; Khranovskyy, V. D.

    2017-01-01

    The wide range of gas sensor application, in particular, in a mining industry for detection of outflow of gases, the control of gas emissions over an atmosphere at the industrial enterprises, in housing and communal services, in home appliances makes actual the review. As the systematized analysis of gas sensor based on ZnO has not being carried out — this work is of interest for development of chemical sensors based on zinc compound with high sensitivity, selectivity and stability. The resis...

  9. An Electronic-Nose Sensor Node Based on a Polymer-Coated Surface Acoustic Wave Array for Wireless Sensor Network Applications

    Science.gov (United States)

    Tang, Kea-Tiong; Li, Cheng-Han; Chiu, Shih-Wen

    2011-01-01

    This study developed an electronic-nose sensor node based on a polymer-coated surface acoustic wave (SAW) sensor array. The sensor node comprised an SAW sensor array, a frequency readout circuit, and an Octopus II wireless module. The sensor array was fabricated on a large K2 128° YX LiNbO3 sensing substrate. On the surface of this substrate, an interdigital transducer (IDT) was produced with a Cr/Au film as its metallic structure. A mixed-mode frequency readout application specific integrated circuit (ASIC) was fabricated using a TSMC 0.18 μm process. The ASIC output was connected to a wireless module to transmit sensor data to a base station for data storage and analysis. This sensor node is applicable for wireless sensor network (WSN) applications. PMID:22163865

  10. An electronic-nose sensor node based on a polymer-coated surface acoustic wave array for wireless sensor network applications.

    Science.gov (United States)

    Tang, Kea-Tiong; Li, Cheng-Han; Chiu, Shih-Wen

    2011-01-01

    This study developed an electronic-nose sensor node based on a polymer-coated surface acoustic wave (SAW) sensor array. The sensor node comprised an SAW sensor array, a frequency readout circuit, and an Octopus II wireless module. The sensor array was fabricated on a large K(2) 128° YX LiNbO3 sensing substrate. On the surface of this substrate, an interdigital transducer (IDT) was produced with a Cr/Au film as its metallic structure. A mixed-mode frequency readout application specific integrated circuit (ASIC) was fabricated using a TSMC 0.18 μm process. The ASIC output was connected to a wireless module to transmit sensor data to a base station for data storage and analysis. This sensor node is applicable for wireless sensor network (WSN) applications.

  11. An Electronic-Nose Sensor Node Based on a Polymer-Coated Surface Acoustic Wave Array for Wireless Sensor Network Applications

    Directory of Open Access Journals (Sweden)

    Kea-Tiong Tang

    2011-04-01

    Full Text Available This study developed an electronic-nose sensor node based on a polymer-coated surface acoustic wave (SAW sensor array. The sensor node comprised an SAW sensor array, a frequency readout circuit, and an Octopus II wireless module. The sensor array was fabricated on a large K2 128° YX LiNbO3 sensing substrate. On the surface of this substrate, an interdigital transducer (IDT was produced with a Cr/Au film as its metallic structure. A mixed-mode frequency readout application specific integrated circuit (ASIC was fabricated using a TSMC 0.18 μm process. The ASIC output was connected to a wireless module to transmit sensor data to a base station for data storage and analysis. This sensor node is applicable for wireless sensor network (WSN applications.

  12. Low Power and High Sensitivity MOSFET-Based Pressure Sensor

    International Nuclear Information System (INIS)

    Zhang Zhao-Hua; Ren Tian-Ling; Zhang Yan-Hong; Han Rui-Rui; Liu Li-Tian

    2012-01-01

    Based on the metal-oxide-semiconductor field effect transistor (MOSFET) stress sensitive phenomenon, a low power MOSFET pressure sensor is proposed. Compared with the traditional piezoresistive pressure sensor, the present pressure sensor displays high performances on sensitivity and power consumption. The sensitivity of the MOSFET sensor is raised by 87%, meanwhile the power consumption is decreased by 20%. (cross-disciplinary physics and related areas of science and technology)

  13. Combined application of FBG and PZT sensors for plantar pressure monitoring at low and high speed walking.

    Science.gov (United States)

    Suresh, R; Bhalla, S; Singh, C; Kaur, N; Hao, J; Anand, S

    2015-01-01

    Clinical monitoring of planar pressure is vital in several pathological conditions, such as diabetes, where excess pressure might have serious repercussions on health of the patient, even to the extent of amputation. The main objective of this paper is to experimentally evaluate the combined application of the Fibre Bragg Grating (FBG) and the lead zirconate titanate (PZT) piezoceramic sensors for plantar pressure monitoring during walk at low and high speeds. For fabrication of the pressure sensors, the FBGs are embedded within layers of carbon composite material and stacked in an arc shape. From this embedding technique, average pressure sensitivity of 1.3 pm/kPa and resolution of nearly 0.8 kPa is obtained. These sensors are found to be suitable for measuring the static and the low-speed walk generated foot pressure. Simultaneously, PZT patches of size 10 × 10 × 0.3 mm were used as sensors, utilizing the d_{33} (thickness) coupling mode. A sensitivity of 7.06 mV/kPa and a pressure resolution of 0.14 kPa is obtained from these sensors, which are found to be suitable for foot pressure measurement during high speed walking and running. Both types of sensors are attached to the underside of the sole of commercially available shoes. In the experiments, a healthy male subject walks/runs over the treadmill wearing the fabricated shoes at various speeds and the peak pressure is measured using both the sensors. Commercially available low-cost hardware is used for interrogation of the two sensor types. The test results clearly show the feasibility of the FBG and the PZT sensors for measurement of plantar pressure. The PZT sensors are more accurate for measurement of pressure during walking at high speeds. The FBG sensors, on the other hand, are found to be suitable for static and quasi-dynamic (slow walking) conditions. Typically, the measured pressure varied from 400 to 600 kPa below the forefoot and 100 to 1000 kPa below the heel as the walking speed varied from 1

  14. Air launch wireless sensor nodes (ALSN) for battle damage assessment (BDA)

    Science.gov (United States)

    Back, Jason M.; Beck, Steven D.; Frank, Mark A.; Hoenes, Eric

    2006-05-01

    This paper summarizes the Defense Threat Reduction Agency (DTRA) sponsored development and demonstration of an Air Launched Sensor Node (ALSN) system designed to fill DTRA's immediate need to support the Global Strike requirement of weapon-borne deliverable sensors for Battle Damage Assessment (BDA). Unattended ground sensors were integrated into a CBU-103 Tactical Munitions Dispenser (TMD), and flight test demonstrated with the 46 th Test Wing at Eglin AFB, FL. The objectives of the ALSN program were to repackage an existing multi-sensor node system to conform to the payload envelope and deployment configuration design; to integrate this payload into the CBU-103 TMD; and to conduct a combined payload flight test demonstration. The final sensor node included multiple sensors a microphone, a geophone, and multiple directional Passive Infrared (PIR) detectors with processing electronics, a low power wireless communications 802.15.4 mesh network, GPS (Global Positioning System), and power integrated into a form-fit BLU-97 munitions deployable package. This paper will present and discuss the flight test, results, and ALSN performance.

  15. Scaling earthquake ground motions for performance-based assessment of buildings

    Science.gov (United States)

    Huang, Y.-N.; Whittaker, A.S.; Luco, N.; Hamburger, R.O.

    2011-01-01

    The impact of alternate ground-motion scaling procedures on the distribution of displacement responses in simplified structural systems is investigated. Recommendations are provided for selecting and scaling ground motions for performance-based assessment of buildings. Four scaling methods are studied, namely, (1)geometric-mean scaling of pairs of ground motions, (2)spectrum matching of ground motions, (3)first-mode-period scaling to a target spectral acceleration, and (4)scaling of ground motions per the distribution of spectral demands. Data were developed by nonlinear response-history analysis of a large family of nonlinear single degree-of-freedom (SDOF) oscillators that could represent fixed-base and base-isolated structures. The advantages and disadvantages of each scaling method are discussed. The relationship between spectral shape and a ground-motion randomness parameter, is presented. A scaling procedure that explicitly considers spectral shape is proposed. ?? 2011 American Society of Civil Engineers.

  16. Intelligent Hardware-Enabled Sensor and Software Safety and Health Management for Autonomous UAS

    Science.gov (United States)

    Rozier, Kristin Y.; Schumann, Johann; Ippolito, Corey

    2015-01-01

    Unmanned Aerial Systems (UAS) can only be deployed if they can effectively complete their mission and respond to failures and uncertain environmental conditions while maintaining safety with respect to other aircraft as well as humans and property on the ground. We propose to design a real-time, onboard system health management (SHM) capability to continuously monitor essential system components such as sensors, software, and hardware systems for detection and diagnosis of failures and violations of safety or performance rules during the ight of a UAS. Our approach to SHM is three-pronged, providing: (1) real-time monitoring of sensor and software signals; (2) signal analysis, preprocessing, and advanced on-the- y temporal and Bayesian probabilistic fault diagnosis; (3) an unobtrusive, lightweight, read-only, low-power hardware realization using Field Programmable Gate Arrays (FPGAs) in order to avoid overburdening limited computing resources or costly re-certi cation of ight software due to instrumentation. No currently available SHM capabilities (or combinations of currently existing SHM capabilities) come anywhere close to satisfying these three criteria yet NASA will require such intelligent, hardwareenabled sensor and software safety and health management for introducing autonomous UAS into the National Airspace System (NAS). We propose a novel approach of creating modular building blocks for combining responsive runtime monitoring of temporal logic system safety requirements with model-based diagnosis and Bayesian network-based probabilistic analysis. Our proposed research program includes both developing this novel approach and demonstrating its capabilities using the NASA Swift UAS as a demonstration platform.

  17. Time-domain fiber loop ringdown sensor and sensor network

    Science.gov (United States)

    Kaya, Malik

    Optical fibers have been mostly used in fiber optic communications, imaging optics, sensing technology, etc. Fiber optic sensors have gained increasing attention for scientific and structural health monitoring (SHM) applications. In this study, fiber loop ringdown (FLRD) sensors were fabricated for scientific, SHM, and sensor networking applications. FLRD biosensors were fabricated for both bulk refractive index (RI)- and surface RI-based DNA sensing and one type of bacteria sensing. Furthermore, the effect of glucose oxidase (GOD) immobilization at the sensor head on sensor performance was evaluated for both glucose and synthetic urine solutions with glucose concentration between 0.1% and 10%. Detection sensitivities of the glucose sensors were achieved as low as 0.05%. For chemical sensing, heavy water, ranging from 97% to 10%, and several elemental solutions were monitored by using the FLRD chemical sensors. Bulk index-based FLRD sensing showed that trace elements can be detected in deionized water. For physical sensing, water and cracking sensors were fabricated and embedded into concrete. A partially-etched single-mode fiber (SMF) was embedded into a concrete bar for water monitoring while a bare SMF without any treatment was directly embedded into another concrete bar for monitoring cracks. Furthermore, detection sensitivities of water and crack sensors were investigated as 10 ml water and 0.5 mm surface crack width, respectively. Additionally fiber loop ringdown-fiber Bragg grating temperature sensors were developed in the laboratory; two sensor units for water, crack, and temperature sensing were deployed into a concrete cube in a US Department of Energy test bed (Miami, FL). Multi-sensor applications in a real concrete structure were accomplished by testing the six FLRD sensors. As a final stage, a sensor network was assembled by multiplexing two or three FLRD sensors in series and parallel. Additionally, two FLRD sensors were combined in series and

  18. Enhanced chemical weapon warning via sensor fusion

    Science.gov (United States)

    Flaherty, Michael; Pritchett, Daniel; Cothren, Brian; Schwaiger, James

    2011-05-01

    Torch Technologies Inc., is actively involved in chemical sensor networking and data fusion via multi-year efforts with Dugway Proving Ground (DPG) and the Defense Threat Reduction Agency (DTRA). The objective of these efforts is to develop innovative concepts and advanced algorithms that enhance our national Chemical Warfare (CW) test and warning capabilities via the fusion of traditional and non-traditional CW sensor data. Under Phase I, II, and III Small Business Innovative Research (SBIR) contracts with DPG, Torch developed the Advanced Chemical Release Evaluation System (ACRES) software to support non real-time CW sensor data fusion. Under Phase I and II SBIRs with DTRA in conjunction with the Edgewood Chemical Biological Center (ECBC), Torch is using the DPG ACRES CW sensor data fuser as a framework from which to develop the Cloud state Estimation in a Networked Sensor Environment (CENSE) data fusion system. Torch is currently developing CENSE to implement and test innovative real-time sensor network based data fusion concepts using CW and non-CW ancillary sensor data to improve CW warning and detection in tactical scenarios.

  19. HIGH-PRECISION ATTITUDE ESTIMATION METHOD OF STAR SENSORS AND GYRO BASED ON COMPLEMENTARY FILTER AND UNSCENTED KALMAN FILTER

    Directory of Open Access Journals (Sweden)

    C. Guo

    2017-07-01

    Full Text Available Determining the attitude of satellite at the time of imaging then establishing the mathematical relationship between image points and ground points is essential in high-resolution remote sensing image mapping. Star tracker is insensitive to the high frequency attitude variation due to the measure noise and satellite jitter, but the low frequency attitude motion can be determined with high accuracy. Gyro, as a short-term reference to the satellite’s attitude, is sensitive to high frequency attitude change, but due to the existence of gyro drift and integral error, the attitude determination error increases with time. Based on the opposite noise frequency characteristics of two kinds of attitude sensors, this paper proposes an on-orbit attitude estimation method of star sensors and gyro based on Complementary Filter (CF and Unscented Kalman Filter (UKF. In this study, the principle and implementation of the proposed method are described. First, gyro attitude quaternions are acquired based on the attitude kinematics equation. An attitude information fusion method is then introduced, which applies high-pass filtering and low-pass filtering to the gyro and star tracker, respectively. Second, the attitude fusion data based on CF are introduced as the observed values of UKF system in the process of measurement updating. The accuracy and effectiveness of the method are validated based on the simulated sensors attitude data. The obtained results indicate that the proposed method can suppress the gyro drift and measure noise of attitude sensors, improving the accuracy of the attitude determination significantly, comparing with the simulated on-orbit attitude and the attitude estimation results of the UKF defined by the same simulation parameters.

  20. Hanford Ground-Water Data Base management guide

    International Nuclear Information System (INIS)

    Rieger, J.T.; Mitchell, P.J.; Muffett, D.M.; Fruland, R.M.; Moore, S.B.; Marshall, S.M.

    1990-02-01

    This guide describes the Hanford Ground-Water Data Base (HGWDB), a computerized data base used to store hydraulic head, sample analytical, temperature, geologic, and well-structure information for ground-water monitoring wells on the Hanford Site. These data are stored for the purpose of data retrieval for report generation and also for historical purposes. This guide is intended as an aid to the data base manager and the various staff authorized to enter and verify data, maintain the data base, and maintain the supporting software. This guide focuses on the structure of the HGWDB, providing a fairly detailed description of the programs, files, and parameters. Data-retrieval instructions for the general user of the HGWDB will be found in the HGWDB User's Manual. 6 figs