WorldWideScience

Sample records for simulation uav-based sensor

  1. UAV-Based Sensor Web Monitoring System

    Directory of Open Access Journals (Sweden)

    Masahiko Nagai

    2012-01-01

    Full Text Available An unmanned aerial vehicle- (UAV- based monitoring system is developed as an intermediate system between aerial survey and ground survey. All the measurement tools are mounted on the UAV to acquire detailed information from low altitudes which is different from a satellite or a plane. The monitoring is carried out from the sky, but the spatial and temporal resolutions are freely selected near the ground. In this study, the data is easily acquired with safety and mobility by the utilization of a sensor web. A sensor web is a type of sensor network which is well suited for environmental monitoring. Sensor nodes are spatially distributed and wirelessly communicate with each other. In this study, the UAV-based system is considered as a mobile sensor node. This study proposes a combination of UAV-based monitoring with a ubiquitous sensor network.

  2. Fleet Protection Using a Small UAV Based IR Sensor

    National Research Council Canada - National Science Library

    Buss, James R; Ax, Jr, George R

    2005-01-01

    A study was performed to define candidate electro-optical and infrared (EO/IR) sensor configurations and assess their potential utility as small UAV-based sensors surveilling a perimeter around surface fleet assets...

  3. Remote sensing of plant trait responses to field-based plant-soil feedback using UAV-based optical sensors

    Science.gov (United States)

    van der Meij, Bob; Kooistra, Lammert; Suomalainen, Juha; Barel, Janna M.; De Deyn, Gerlinde B.

    2017-02-01

    Plant responses to biotic and abiotic legacies left in soil by preceding plants is known as plant-soil feedback (PSF). PSF is an important mechanism to explain plant community dynamics and plant performance in natural and agricultural systems. However, most PSF studies are short-term and small-scale due to practical constraints for field-scale quantification of PSF effects, yet field experiments are warranted to assess actual PSF effects under less controlled conditions. Here we used unmanned aerial vehicle (UAV)-based optical sensors to test whether PSF effects on plant traits can be quantified remotely. We established a randomized agro-ecological field experiment in which six different cover crop species and species combinations from three different plant families (Poaceae, Fabaceae, Brassicaceae) were grown. The feedback effects on plant traits were tested in oat (Avena sativa) by quantifying the cover crop legacy effects on key plant traits: height, fresh biomass, nitrogen content, and leaf chlorophyll content. Prior to destructive sampling, hyperspectral data were acquired and used for calibration and independent validation of regression models to retrieve plant traits from optical data. Subsequently, for each trait the model with highest precision and accuracy was selected. We used the hyperspectral analyses to predict the directly measured plant height (RMSE = 5.12 cm, R2 = 0.79), chlorophyll content (RMSE = 0.11 g m-2, R2 = 0.80), N-content (RMSE = 1.94 g m-2, R2 = 0.68), and fresh biomass (RMSE = 0.72 kg m-2, R2 = 0.56). Overall the PSF effects of the different cover crop treatments based on the remote sensing data matched the results based on in situ measurements. The average oat canopy was tallest and its leaf chlorophyll content highest in response to legacy of Vicia sativa monocultures (100 cm, 0.95 g m-2, respectively) and in mixture with Raphanus sativus (100 cm, 1.09 g m-2, respectively), while the lowest values (76 cm, 0.41 g m-2, respectively

  4. High Temperature Chemical Sensor Array Payload For UAV Based In-situ Volcanic Gas Measurements, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. proposes to develop a low cost, UAV based microsensor array payload for monitoring volcanic processes such as plume vents and hot lava flows....

  5. Impact of plant-soil feedback on plant traits at field scale, testing the use of UAV-based optical sensors

    Science.gov (United States)

    De Deyn, Gerlinde B.; van der Meij, Bob; Barel, Janna M.; Suomalainen, Juha; Kooistra, Lammert

    2017-04-01

    Plant responses to biotic and abiotic legacies left in soil by preceding plants is known as plant-soil feedback (PSF). PSF is an important mechanism to explain plant community dynamics and plant performance in natural and agricultural systems. However, most PSF studies are short-term and small-scale due to practical constraints for field scale quantification of PSF effects, yet field experiments are warranted to asses actual PSF effects under less controlled conditions. Here we used Unmanned Aerial Vehicle (UAV)-based optical sensors to test whether PSF effects on plant traits can be quantified remotely. We established a randomized agro-ecological field experiment in which six different cover crop species and species combinations from three different plant families (Poaceae, Fabaceae, Brassicaceae) were grown. The feedback effects on plant traits were tested in oat (Avena sativa) by quantifying the cover crop legacy effects on key plant traits: height, fresh biomass, nitrogen content and leaf chlorophyll content. Prior to destructive sampling, hyperspectral data was acquired and used for calibration and independent validation of regression models to retrieve plant traits from optical data. Subsequently, for each trait the model with highest precision and accuracy was selected. We used the hyperspectral analyses to predict the directly measured plant height (RMSE= 5.12 cm, R2= 0.79), chlorophyll content (RMSE= 0.11 g m-2, R2= 0.80), N-content (RMSE= 1.94 g m-2, R2= 0.68), and fresh biomass (RMSE= 0.72 kg m-2, R2=0.56). Overall the PSF effects of the different cover crop treatments based on the remote sensing data matched the results based on in situ measurements. The average oat canopy was tallest and its leaf chlorophyll content highest in response to legacy of Vicia sativa monocultures (100 cm, 0.95 g m-2, respectively) and in mixture with Raphanus sativus (100 cm, 1.09 g m-2, respectively), while the lowest values (76 cm, 0.41 g m-2, respectively) were found in

  6. DESIGN AND IMPLEMENTATION OF A LOW-COST UAV-BASED MULTI-SENSOR PAYLOAD FOR RAPID-RESPONSE MAPPING APPLICATIONS

    Directory of Open Access Journals (Sweden)

    M. Sakr

    2016-06-01

    Full Text Available The main objective of this paper is to investigate the potential of using Unmanned Aerial Vehicles (UAVs as a platform to collect geospatial data for rapid response applications, especially in hard-to-access and hazardous areas. The UAVs are low-cost mapping vehicles, and they are easy to handle and deploy in-field. These characteristics make UAVs ideal candidates for rapid-response and disaster mitigation scenarios. The majority of the available UAV systems are not capable of real-time/near real-time data processing. This paper introduces a low-cost UAV-based multi-sensor mapping payload which supports real-time processing and can be effectively used in rapid-response applications. The paper introduces the main components of the system, and provides an overview of the proposed payload architecture. Then, it introduces the implementation details of the major building blocks of the system. Finally, the paper presents our conclusions and the future work, in order to achieve real-time/near real-time data processing and product delivery capabilities.

  7. Hyperspectral Imaging: A Review on UAV-Based Sensors, Data Processing and Applications for Agriculture and Forestry

    Directory of Open Access Journals (Sweden)

    Telmo Adão

    2017-10-01

    Full Text Available Traditional imagery—provided, for example, by RGB and/or NIR sensors—has proven to be useful in many agroforestry applications. However, it lacks the spectral range and precision to profile materials and organisms that only hyperspectral sensors can provide. This kind of high-resolution spectroscopy was firstly used in satellites and later in manned aircraft, which are significantly expensive platforms and extremely restrictive due to availability limitations and/or complex logistics. More recently, UAS have emerged as a very popular and cost-effective remote sensing technology, composed of aerial platforms capable of carrying small-sized and lightweight sensors. Meanwhile, hyperspectral technology developments have been consistently resulting in smaller and lighter sensors that can currently be integrated in UAS for either scientific or commercial purposes. The hyperspectral sensors’ ability for measuring hundreds of bands raises complexity when considering the sheer quantity of acquired data, whose usefulness depends on both calibration and corrective tasks occurring in pre- and post-flight stages. Further steps regarding hyperspectral data processing must be performed towards the retrieval of relevant information, which provides the true benefits for assertive interventions in agricultural crops and forested areas. Considering the aforementioned topics and the goal of providing a global view focused on hyperspectral-based remote sensing supported by UAV platforms, a survey including hyperspectral sensors, inherent data processing and applications focusing both on agriculture and forestry—wherein the combination of UAV and hyperspectral sensors plays a center role—is presented in this paper. Firstly, the advantages of hyperspectral data over RGB imagery and multispectral data are highlighted. Then, hyperspectral acquisition devices are addressed, including sensor types, acquisition modes and UAV-compatible sensors that can be used

  8. A UAV-BASED ROE DEER FAWN DETECTION SYSTEM

    Directory of Open Access Journals (Sweden)

    M. Israel

    2012-09-01

    Full Text Available This paper presents a UAV based remote sensing system for the detection of fawns in the meadows. There is a high demand because during pasture mowing many wild animals, especially roe deer fawns are killed by mowing machines. The system was tested in several real situations especially with differing weather and iluminating conditions. Its primary sensor is a lightweight thermal infrared camera. The images are captured onboard of the flight system and also transmitted as analog video stream to the ground station, where the user can follow the camera live stream on a monitor for manual animal detection. Beside a high detection rate a fast workflow is another very important objective for this application. Therefore a waypoint planning software was developed that accelerates the workflow. At adequate illuminating and weather conditions the presented UAV-based fawn detection via thermal imaging is a comfortable, fast and reliable method.

  9. a Uav-Based ROE Deer Fawn Detection System

    Science.gov (United States)

    Israel, M.

    2011-09-01

    This paper presents a UAV based remote sensing system for the detection of fawns in the meadows. There is a high demand because during pasture mowing many wild animals, especially roe deer fawns are killed by mowing machines. The system was tested in several real situations especially with differing weather and iluminating conditions. Its primary sensor is a lightweight thermal infrared camera. The images are captured onboard of the flight system and also transmitted as analog video stream to the ground station, where the user can follow the camera live stream on a monitor for manual animal detection. Beside a high detection rate a fast workflow is another very important objective for this application. Therefore a waypoint planning software was developed that accelerates the workflow. At adequate illuminating and weather conditions the presented UAV-based fawn detection via thermal imaging is a comfortable, fast and reliable method.

  10. Results from Real Time Simulation Experiment of an Integrated Concept for UAV/Direct Fire Weapon Systems

    National Research Council Canada - National Science Library

    Melendez, Gerardo; Gallivan, Elizabeth; Kenneally, William; SantaPietro, John; Wiener, Stephen

    2006-01-01

    During the last several years, there have been a large number of design studies, system simulations, and battlelab experiments that have sought to improve the integration of UAV-based sensor systems...

  11. Motion sensor evaluation using simulation

    International Nuclear Information System (INIS)

    Schmutz, J.D.; McNerney, G.M.; Workhoven, R.M.

    1984-01-01

    Thorough evaluation testing of interior motion sensors requires repeated testing under a variety of environmental conditions. Although the sensors are intended primarily for interior installations, many of the buildings where protection may be required are warehouses or bunkers without environmental control. In evaluating sensors for such installations, it becomes important to collect data not only on coverage or sensitivity at room temperature but also at environmental extremes. This paper describes a system Sandia National Laboratories at Albuquerque (SNLA) has designed and built to provide repeatability in environmental testing. The system has been dubbed Sandia Intruder Motion Simulator (SIMS). This system is used to acquire much of the data now collected on sensors in the laboratory and a duplicate system has been delivered to the Belvoir R and D Center so that the laboratory can now run similar tests. 11 figures

  12. UAV-based photogrammetric 3D modelling and surveillance of forest wildfires

    OpenAIRE

    Krukowski, Artur; Vogiatzaki, Emmanouela

    2017-01-01

    This article presents work performed in the frame of ongoing FP7-SEC project “Advanced Forest Fire Fighting” in areas of UAV-based 3D surveillance and 3D area mapping. Photogrammetric 3D scanning and modelling from H2020-SCAN4RECO project have been used for producing high-resolution models of incident areas from multi-spectral imaging. We also present a proprietary embedded sensor system used for detection of fire ignitions in the forest using near-infrared based scanner with weight and form ...

  13. Developing a UAV-based rapid mapping system for emergency response

    Science.gov (United States)

    Choi, Kyoungah; Lee, Impyeong; Hong, Juseok; Oh, Taewan; Shin, Sung Woong

    2009-05-01

    As disasters and accidents due to various natural or artificial causes being increased, the demands for rapid responses for emergency situations also have been ever-increasing. These emergency responses need to be not only more intelligent but also more customized to the individual sites to manage the emergency situations more efficiently. More effective counter-measures in such situations will be established only if more accurate and prompt spatial information about the changing areas due to the emergency are available. This information can be rapidly extracted from the airborne sensory data acquired by a UAV-based rapid mapping system. This paper introduces a Korean national project to develop a UAV-based rapid mapping system. The overall budget is about 6 million US dollars and the period is about four years. The goal of this project is to develop a light and flexible system at low cost to perform rapid mapping for emergency responses. This system consists of two main parts, aerial part and ground part. The aerial part includes a small UAV platform equipped with sensors (GPS/IMU/Camera/Laser Scanner) and sensor supporting modules for sensor integration, data transmission to the ground, data storages, time synchronization, and sensor stabilization. The ground part includes three sub-systems with appropriate software, which are a control/receiving/archiving subsystem, a data georeferencing subsystem, and a spatial information generation subsystem. As being in a middle stage of this project, we will present a brief introduction to the overall project and the design of the aerial system with its verification results.

  14. The Altus Cumulus Electrification Study (ACES): A UAV-Based Science Demonstration

    Science.gov (United States)

    Blakeslee, R. J.; Croskey, C. L.; Desch, M. D.; Farrell, W. M.; Goldberg, R. A.; Houser, J. G.; Kim, H. S.; Mach, D. M.; Mitchell, J. D.; Stoneburner, J. C.

    2003-01-01

    The Altus Cumulus Electrification Study (ACES) is an unmanned aerial vehicle (UAV)- based project that investigated thunderstorms in the vicinity of the Florida Everglades in August 2002. ACES was conducted to investigate storm electrical activity and its relationship to storm morphology, and to validate satellite-based lightning measurements. In addition, as part of the NASA sponsored UAV-based science demonstration program, this project provided a scientifically useful demonstration of the utility and promise of UAV platforms for Earth science and applications observations. ACES employed the Altus II aircraft, built by General Atomics - Aeronautical Systems, Inc. Key science objectives simultaneously addressed by ACES are to: (1) investigate lightning-storm relationships, (2) study storm electrical budgets, and provide Lightning Imaging Sensor validation. The ACES payload included electrical, magnetic, and optical sensors to remotely characterize the lightning activity and the electrical environment within and around thunderstorms. ACES contributed important electrical and optical measurements not available from other sources. Also, the high altitude vantage point of the UAV observing platform (up to 55,000 feet) provided cloud-top perspective. By taking advantage of its slow flight speed (70 to 100 knots), long endurance, and high altitude flight, the Altus was flown near, and when possible, over (but never into) thunderstorms for long periods of time that allowed investigations to be conducted over entire storm life cycles. An innovative real time weather system was used to identify and vector the aircraft to selected thunderstorms and safely fly around these storms, while, at the same time monitor the weather near our base of operations. In addition, concurrent ground-based observations that included radar (Miami and Key West WSRBD, NASA NPOL), satellite imagery, and lightning (NALDN and Los Alamos EDOT) enable the UAV measurements to be more completely

  15. Contour Detection for UAV-Based Cadastral Mapping

    Directory of Open Access Journals (Sweden)

    Sophie Crommelinck

    2017-02-01

    Full Text Available Unmanned aerial vehicles (UAVs provide a flexible and low-cost solution for the acquisition of high-resolution data. The potential of high-resolution UAV imagery to create and update cadastral maps is being increasingly investigated. Existing procedures generally involve substantial fieldwork and many manual processes. Arguably, multiple parts of UAV-based cadastral mapping workflows could be automated. Specifically, as many cadastral boundaries coincide with visible boundaries, they could be extracted automatically using image analysis methods. This study investigates the transferability of gPb contour detection, a state-of-the-art computer vision method, to remotely sensed UAV images and UAV-based cadastral mapping. Results show that the approach is transferable to UAV data and automated cadastral mapping: object contours are comprehensively detected at completeness and correctness rates of up to 80%. The detection quality is optimal when the entire scene is covered with one orthoimage, due to the global optimization of gPb contour detection. However, a balance between high completeness and correctness is hard to achieve, so a combination with area-based segmentation and further object knowledge is proposed. The localization quality exhibits the usual dependency on ground resolution. The approach has the potential to accelerate the process of general boundary delineation during the creation and updating of cadastral maps.

  16. Automated geographic registration and radiometric correction for UAV-based mosaics

    Science.gov (United States)

    Texas A&M University has been operating a large-scale, UAV-based, agricultural remote-sensing research project since 2015. To use UAV-based images in agricultural production, many high-resolution images must be mosaicked together to create an image of an agricultural field. Two key difficulties to s...

  17. POTENTIAL OF UAV-BASED LASER SCANNER AND MULTISPECTRAL CAMERA DATA IN BUILDING INSPECTION

    Directory of Open Access Journals (Sweden)

    D. Mader

    2016-06-01

    Full Text Available Conventional building inspection of bridges, dams or large constructions in general is rather time consuming and often cost expensive due to traffic closures and the need of special heavy vehicles such as under-bridge inspection units or other large lifting platforms. In consideration that, an unmanned aerial vehicle (UAV will be more reliable and efficient as well as less expensive and simpler to operate. The utilisation of UAVs as an assisting tool in building inspections is obviously. Furthermore, light-weight special sensors such as infrared and thermal cameras as well as laser scanner are available and predestined for usage on unmanned aircraft systems. Such a flexible low-cost system is realized in the ADFEX project with the goal of time-efficient object exploration, monitoring and damage detection. For this purpose, a fleet of UAVs, equipped with several sensors for navigation, obstacle avoidance and 3D object-data acquisition, has been developed and constructed. This contribution deals with the potential of UAV-based data in building inspection. Therefore, an overview of the ADFEX project, sensor specifications and requirements of building inspections in general are given. On the basis of results achieved in practical studies, the applicability and potential of the UAV system in building inspection will be presented and discussed.

  18. Numerical simulation of mechatronic sensors and actuators

    CERN Document Server

    Kaltenbacher, Manfred

    2007-01-01

    Focuses on the physical modeling of mechatronic sensors and actuators and their precise numerical simulation using the Finite Element Method (FEM). This book discusses the physical modeling as well as numerical computation. It also gives a comprehensive introduction to finite elements, including their computer implementation.

  19. Development and Validation of a UAV Based System for Air Pollution Measurements

    Science.gov (United States)

    Villa, Tommaso Francesco; Salimi, Farhad; Morton, Kye; Morawska, Lidia; Gonzalez, Felipe

    2016-01-01

    Air quality data collection near pollution sources is difficult, particularly when sites are complex, have physical barriers, or are themselves moving. Small Unmanned Aerial Vehicles (UAVs) offer new approaches to air pollution and atmospheric studies. However, there are a number of critical design decisions which need to be made to enable representative data collection, in particular the location of the air sampler or air sensor intake. The aim of this research was to establish the best mounting point for four gas sensors and a Particle Number Concentration (PNC) monitor, onboard a hexacopter, so to develop a UAV system capable of measuring point source emissions. The research included two different tests: (1) evaluate the air flow behavior of a hexacopter, its downwash and upwash effect, by measuring air speed along three axes to determine the location where the sensors should be mounted; (2) evaluate the use of gas sensors for CO2, CO, NO2 and NO, and the PNC monitor (DISCmini) to assess the efficiency and performance of the UAV based system by measuring emissions from a diesel engine. The air speed behavior map produced by test 1 shows the best mounting point for the sensors to be alongside the UAV. This position is less affected by the propeller downwash effect. Test 2 results demonstrated that the UAV propellers cause a dispersion effect shown by the decrease of gas and PN concentration measured in real time. A Linear Regression model was used to estimate how the sensor position, relative to the UAV center, affects pollutant concentration measurements when the propellers are turned on. This research establishes guidelines on how to develop a UAV system to measure point source emissions. Such research should be undertaken before any UAV system is developed for real world data collection. PMID:28009820

  20. Development and Validation of a UAV Based System for Air Pollution Measurements

    Directory of Open Access Journals (Sweden)

    Tommaso Francesco Villa

    2016-12-01

    Full Text Available Air quality data collection near pollution sources is difficult, particularly when sites are complex, have physical barriers, or are themselves moving. Small Unmanned Aerial Vehicles (UAVs offer new approaches to air pollution and atmospheric studies. However, there are a number of critical design decisions which need to be made to enable representative data collection, in particular the location of the air sampler or air sensor intake. The aim of this research was to establish the best mounting point for four gas sensors and a Particle Number Concentration (PNC monitor, onboard a hexacopter, so to develop a UAV system capable of measuring point source emissions. The research included two different tests: (1 evaluate the air flow behavior of a hexacopter, its downwash and upwash effect, by measuring air speed along three axes to determine the location where the sensors should be mounted; (2 evaluate the use of gas sensors for CO2, CO, NO2 and NO, and the PNC monitor (DISCmini to assess the efficiency and performance of the UAV based system by measuring emissions from a diesel engine. The air speed behavior map produced by test 1 shows the best mounting point for the sensors to be alongside the UAV. This position is less affected by the propeller downwash effect. Test 2 results demonstrated that the UAV propellers cause a dispersion effect shown by the decrease of gas and PN concentration measured in real time. A Linear Regression model was used to estimate how the sensor position, relative to the UAV center, affects pollutant concentration measurements when the propellers are turned on. This research establishes guidelines on how to develop a UAV system to measure point source emissions. Such research should be undertaken before any UAV system is developed for real world data collection.

  1. Development and Validation of a UAV Based System for Air Pollution Measurements.

    Science.gov (United States)

    Villa, Tommaso Francesco; Salimi, Farhad; Morton, Kye; Morawska, Lidia; Gonzalez, Felipe

    2016-12-21

    Air quality data collection near pollution sources is difficult, particularly when sites are complex, have physical barriers, or are themselves moving. Small Unmanned Aerial Vehicles (UAVs) offer new approaches to air pollution and atmospheric studies. However, there are a number of critical design decisions which need to be made to enable representative data collection, in particular the location of the air sampler or air sensor intake. The aim of this research was to establish the best mounting point for four gas sensors and a Particle Number Concentration (PNC) monitor, onboard a hexacopter, so to develop a UAV system capable of measuring point source emissions. The research included two different tests: (1) evaluate the air flow behavior of a hexacopter, its downwash and upwash effect, by measuring air speed along three axes to determine the location where the sensors should be mounted; (2) evaluate the use of gas sensors for CO₂, CO, NO₂ and NO, and the PNC monitor (DISCmini) to assess the efficiency and performance of the UAV based system by measuring emissions from a diesel engine. The air speed behavior map produced by test 1 shows the best mounting point for the sensors to be alongside the UAV. This position is less affected by the propeller downwash effect. Test 2 results demonstrated that the UAV propellers cause a dispersion effect shown by the decrease of gas and PN concentration measured in real time. A Linear Regression model was used to estimate how the sensor position, relative to the UAV center, affects pollutant concentration measurements when the propellers are turned on. This research establishes guidelines on how to develop a UAV system to measure point source emissions. Such research should be undertaken before any UAV system is developed for real world data collection.

  2. UAV Based Imaging for Crop, Weed and Disease Monitoring

    DEFF Research Database (Denmark)

    Garcia Ruiz, Francisco Jose

    provides evidence, through real applications, of the potential for UAV based remote sensing for improved weed and disease detection in agriculture. It showed that it was possible to discriminate between sugar beet and thistle based on their field spectral signature captured with a field portable...... the physiological status of the vegetation. UAV imagery may be divided into three steps (1) spectral characterization of the targets of interest, (2) flight and image acquisition and (3) image processing and interpretation. The overall aims of this study were to improve knowledge in all three steps associated......Summary Unmanned aerial vehicles (UAV) equipped with cameras have become a powerful technology to collect high resolution remote sensing data from agricultural crops. When equipped with multispectral cameras, light invisible for the human eye may be captured and used to characterize...

  3. Millimeter waves sensor modeling and simulation

    Science.gov (United States)

    Latger, Jean; Cathala, Thierry

    2015-10-01

    Guidance of weapon systems relies on sensors to analyze targets signature. Defense weapon systems also need to detect then identify threats also using sensors. One important class of sensors are millimeter waves radar systems that are very efficient for seeing through atmosphere and/or foliage for example. This type of high frequency radar can produce high quality images with very tricky features such as dihedral and trihedral bright points, shadows and lay over effect. Besides, image quality is very dependent on the carrier velocity and trajectory. Such sensors systems are so complex that they need simulation to be tested. This paper presents a state of the Art of millimeter waves sensor models. A short presentation of asymptotic methods shows that physical optics support is mandatory to reach realistic results. SE-Workbench-RF tool is presented and typical examples of results are shown both in the frame of Synthetic Aperture Radar sensors and Real Beam Ground Mapping radars. Several technical topics are then discussed, such as the rendering technique (ray tracing vs. rasterization), the implementation (CPU vs. GP GPU) and the tradeoff between physical accuracy and performance of computation. Examples of results using SE-Workbench-RF are showed and commented.

  4. Space environment simulation and sensor calibration facility

    Science.gov (United States)

    Engelhart, Daniel P.; Patton, James; Plis, Elena; Cooper, Russell; Hoffmann, Ryan; Ferguson, Dale; Hilmer, Robert V.; McGarity, John; Holeman, Ernest

    2018-02-01

    The Mumbo space environment simulation chamber discussed here comprises a set of tools to calibrate a variety of low flux, low energy electron and ion detectors used in satellite-mounted particle sensors. The chamber features electron and ion beam sources, a Lyman-alpha ultraviolet lamp, a gimbal table sensor mounting system, cryogenic sample mount and chamber shroud, and beam characterization hardware and software. The design of the electron and ion sources presented here offers a number of unique capabilities for space weather sensor calibration. Both sources create particle beams with narrow, well-characterized energetic and angular distributions with beam diameters that are larger than most space sensor apertures. The electron and ion sources can produce consistently low fluxes that are representative of quiescent space conditions. The particle beams are characterized by 2D beam mapping with several co-located pinhole aperture electron multipliers to capture relative variation in beam intensity and a large aperture Faraday cup to measure absolute current density.

  5. Benchmarking the Optical Resolving Power of Uav Based Camera Systems

    Science.gov (United States)

    Meißner, H.; Cramer, M.; Piltz, B.

    2017-08-01

    UAV based imaging and 3D object point generation is an established technology. Some of the UAV users try to address (very) highaccuracy applications, i.e. inspection or monitoring scenarios. In order to guarantee such level of detail and accuracy high resolving imaging systems are mandatory. Furthermore, image quality considerably impacts photogrammetric processing, as the tie point transfer, mandatory for forming the block geometry, fully relies on the radiometric quality of images. Thus, empirical testing of radiometric camera performance is an important issue, in addition to standard (geometric) calibration, which normally is covered primarily. Within this paper the resolving power of ten different camera/lens installations has been investigated. Selected systems represent different camera classes, like DSLRs, system cameras, larger format cameras and proprietary systems. As the systems have been tested in wellcontrolled laboratory conditions and objective quality measures have been derived, individual performance can be compared directly, thus representing a first benchmark on radiometric performance of UAV cameras. The results have shown, that not only the selection of appropriate lens and camera body has an impact, in addition the image pre-processing, i.e. the use of a specific debayering method, significantly influences the final resolving power.

  6. BENCHMARKING THE OPTICAL RESOLVING POWER OF UAV BASED CAMERA SYSTEMS

    Directory of Open Access Journals (Sweden)

    H. Meißner

    2017-08-01

    Full Text Available UAV based imaging and 3D object point generation is an established technology. Some of the UAV users try to address (very highaccuracy applications, i.e. inspection or monitoring scenarios. In order to guarantee such level of detail and accuracy high resolving imaging systems are mandatory. Furthermore, image quality considerably impacts photogrammetric processing, as the tie point transfer, mandatory for forming the block geometry, fully relies on the radiometric quality of images. Thus, empirical testing of radiometric camera performance is an important issue, in addition to standard (geometric calibration, which normally is covered primarily. Within this paper the resolving power of ten different camera/lens installations has been investigated. Selected systems represent different camera classes, like DSLRs, system cameras, larger format cameras and proprietary systems. As the systems have been tested in wellcontrolled laboratory conditions and objective quality measures have been derived, individual performance can be compared directly, thus representing a first benchmark on radiometric performance of UAV cameras. The results have shown, that not only the selection of appropriate lens and camera body has an impact, in addition the image pre-processing, i.e. the use of a specific debayering method, significantly influences the final resolving power.

  7. POTENTIAL OF UAV BASED CONVERGENT PHOTOGRAMMETRY IN MONITORING REGENERATION STANDARDS

    Directory of Open Access Journals (Sweden)

    U. Vepakomma

    2015-08-01

    Full Text Available Several thousand hectares of forest blocks are regenerating after harvest in Canada. Monitoring their performance over different stages of growth is critical in ensuring future productivity and ecological balance. Tools for rapid evaluation can support timely and reliable planning of interventions. Conventional ground surveys or visual image assessments are either time intensive or inaccurate, while alternate operational remote sensing tools are unavailable. In this study, we test the feasibility and strength of UAV-based photogrammetry with an EO camera on a UAV platform in assessing regeneration performance. Specifically we evaluated stocking, spatial density and height distribution of naturally growing (irregularly spaced stems or planted (regularly spaced stems conifer regeneration in different phases of growth. Standard photogrammetric workflow was applied on the 785 acquired images for 3D reconstruction of the study sites. The required parameters were derived based on automated single stem detection algorithm developed in-house. Comparing with field survey data, preliminary results hold promise. Future studies are planned to expand the scope to larger areas and different stand conditions.

  8. DTM Generation with Uav Based Photogrammetric Point Cloud

    Science.gov (United States)

    Polat, N.; Uysal, M.

    2017-11-01

    Nowadays Unmanned Aerial Vehicles (UAVs) are widely used in many applications for different purposes. Their benefits however are not entirely detected due to the integration capabilities of other equipment such as; digital camera, GPS, or laser scanner. The main scope of this paper is evaluating performance of cameras integrated UAV for geomatic applications by the way of Digital Terrain Model (DTM) generation in a small area. In this purpose, 7 ground control points are surveyed with RTK and 420 photographs are captured. Over 30 million georeferenced points were used in DTM generation process. Accuracy of the DTM was evaluated with 5 check points. The root mean square error is calculated as 17.1 cm for an altitude of 100 m. Besides, a LiDAR derived DTM is used as reference in order to calculate correlation. The UAV based DTM has o 94.5 % correlation with reference DTM. Outcomes of the study show that it is possible to use the UAV Photogrammetry data as map producing, surveying, and some other engineering applications with the advantages of low-cost, time conservation, and minimum field work.

  9. DTM GENERATION WITH UAV BASED PHOTOGRAMMETRIC POINT CLOUD

    Directory of Open Access Journals (Sweden)

    N. Polat

    2017-11-01

    Full Text Available Nowadays Unmanned Aerial Vehicles (UAVs are widely used in many applications for different purposes. Their benefits however are not entirely detected due to the integration capabilities of other equipment such as; digital camera, GPS, or laser scanner. The main scope of this paper is evaluating performance of cameras integrated UAV for geomatic applications by the way of Digital Terrain Model (DTM generation in a small area. In this purpose, 7 ground control points are surveyed with RTK and 420 photographs are captured. Over 30 million georeferenced points were used in DTM generation process. Accuracy of the DTM was evaluated with 5 check points. The root mean square error is calculated as 17.1 cm for an altitude of 100 m. Besides, a LiDAR derived DTM is used as reference in order to calculate correlation. The UAV based DTM has o 94.5 % correlation with reference DTM. Outcomes of the study show that it is possible to use the UAV Photogrammetry data as map producing, surveying, and some other engineering applications with the advantages of low-cost, time conservation, and minimum field work.

  10. THE PRACTICAL APPLICATION OF UAV-BASED PHOTOGRAMMETRY UNDER ECONOMIC ASPECTS

    Directory of Open Access Journals (Sweden)

    M. Sauerbier

    2012-09-01

    Full Text Available Nowadays, small size UAVs (Unmanned Aerial Vehicles have reached a level of practical reliability and functionality that enables this technology to enter the geomatics market as an additional platform for spatial data acquisition. Though one could imagine a wide variety of interesting sensors to be mounted on such a device, here we will focus on photogrammetric applications using digital cameras. In praxis, UAV-based photogrammetry will only be accepted if it a provides the required accuracy and an additional value and b if it is competitive in terms of economic application compared to other measurement technologies. While a was already proven by the scientific community and results were published comprehensively during the last decade, b still has to be verified under real conditions. For this purpose, a test data set representing a realistic scenario provided by ETH Zurich was used to investigate cost effectiveness and to identify weak points in the processing chain that require further development. Our investigations are limited to UAVs carrying digital consumer cameras, for larger UAVs equipped with medium format cameras the situation has to be considered as significantly different. Image data was acquired during flights using a microdrones MD4-1000 quadrocopter equipped with an Olympus PE-1 digital compact camera. From these images, a subset of 5 images was selected for processing in order to register the effort of time required for the whole production chain of photogrammetric products. We see the potential of mini UAV-based photogrammetry mainly in smaller areas, up to a size of ca. 100 hectares. Larger areas can be efficiently covered by small airplanes with few images, reducing processing effort drastically. In case of smaller areas of a few hectares only, it depends more on the products required. UAVs can be an enhancement or alternative to GNSS measurements, terrestrial laser scanning and ground based photogrammetry. We selected the

  11. 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.

  12. UAV based hydromorphological mapping of a river reach to improve hydrodynamic numerical models

    Science.gov (United States)

    Lükő, Gabriella; Baranya, Sándor; Rüther, Nils

    2017-04-01

    Unmanned Aerial Vehicles (UAVs) are increasingly used in the field of engineering surveys. In river engineering, or in general, water resources engineering, UAV based measurements have a huge potential. For instance, indirect measurements of the flow discharge using e.g. large-scale particle image velocimetry (LSPIV), particle tracking velocimetry (PTV), space-time image velocimetry (STIV) or radars became a real alternative for direct flow measurements. Besides flow detection, topographic surveys are also essential for river flow studies as the channel and floodplain geometry is the primary steering feature of the flow. UAVs can play an important role in this field, too. The widely used laser based topographic survey method (LIDAR) can be deployed on UAVs, moreover, the application of the Structure from Motion (SfM) method, which is based on images taken by UAVs, might be an even more cost-efficient alternative to reveal the geometry of distinct objects in the river or on the floodplain. The goal of this study is to demonstrate the utilization of photogrammetry and videogrammetry from airborne footage to provide geometry and flow data for a hydrodynamic numerical simulation of a 2 km long river reach in Albania. First, the geometry of the river is revealed from photogrammetry using the SfM method. Second, a more detailed view of the channel bed at low water level is taken. Using the fine resolution images, a Matlab based code, BASEGrain, developed by the ETH in Zürich, will be applied to determine the grain size characteristics of the river bed. This information will be essential to define the hydraulic roughness in the numerical model. Third, flow mapping is performed using UAV measurements and LSPIV method to quantitatively asses the flow field at the free surface and to estimate the discharge in the river. All data collection and analysis will be carried out using a simple, low-cost UAV, moreover, for all the data processing, open source, freely available

  13. UAV-Based Hyperspectral Remote Sensing for Precision Agriculture: Challenges and Opportunities

    Science.gov (United States)

    Angel, Y.; Parkes, S. D.; Turner, D.; Houborg, R.; Lucieer, A.; McCabe, M.

    2017-12-01

    Modern agricultural production relies on monitoring crop status by observing and measuring variables such as soil condition, plant health, fertilizer and pesticide effect, irrigation and crop yield. Managing all of these factors is a considerable challenge for crop producers. As such, providing integrated technological solutions that enable improved diagnostics of field condition to maximize profits, while minimizing environmental impacts, would be of much interest. Such challenges can be addressed by implementing remote sensing systems such as hyperspectral imaging to produce precise biophysical indicator maps across the various cycles of crop development. Recent progress in unmanned aerial vehicles (UAVs) have advanced traditional satellite-based capabilities, providing a capacity for high-spatial, spectral and temporal response. However, while some hyperspectral sensors have been developed for use onboard UAVs, significant investment is required to develop a system and data processing workflow that retrieves accurately georeferenced mosaics. Here we explore the use of a pushbroom hyperspectral camera that is integrated on-board a multi-rotor UAV system to measure the surface reflectance in 272 distinct spectral bands across a wavelengths range spanning 400-1000 nm, and outline the requirement for sensor calibration, integration onto a stable UAV platform enabling accurate positional data, flight planning, and development of data post-processing workflows for georeferenced mosaics. The provision of high-quality and geo-corrected imagery facilitates the development of metrics of vegetation health that can be used to identify potential problems such as production inefficiencies, diseases and nutrient deficiencies and other data-streams to enable improved crop management. Immense opportunities remain to be exploited in the implementation of UAV-based hyperspectral sensing (and its combination with other imaging systems) to provide a transferable and scalable

  14. 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.

  15. Power Aware Simulation Framework for Wireless Sensor Networks and Nodes

    Directory of Open Access Journals (Sweden)

    Glaser Johann

    2008-01-01

    Full Text Available Abstract The constrained resources of sensor nodes limit analytical techniques and cost-time factors limit test beds to study wireless sensor networks (WSNs. Consequently, simulation becomes an essential tool to evaluate such systems.We present the power aware wireless sensors (PAWiS simulation framework that supports design and simulation of wireless sensor networks and nodes. The framework emphasizes power consumption capturing and hence the identification of inefficiencies in various hardware and software modules of the systems. These modules include all layers of the communication system, the targeted class of application itself, the power supply and energy management, the central processing unit (CPU, and the sensor-actuator interface. The modular design makes it possible to simulate heterogeneous systems. PAWiS is an OMNeT++ based discrete event simulator written in C++. It captures the node internals (modules as well as the node surroundings (network, environment and provides specific features critical to WSNs like capturing power consumption at various levels of granularity, support for mobility, and environmental dynamics as well as the simulation of timing effects. A module library with standardized interfaces and a power analysis tool have been developed to support the design and analysis of simulation models. The performance of the PAWiS simulator is comparable with other simulation environments.

  16. Power Aware Simulation Framework for Wireless Sensor Networks and Nodes

    Directory of Open Access Journals (Sweden)

    Daniel Weber

    2008-07-01

    Full Text Available The constrained resources of sensor nodes limit analytical techniques and cost-time factors limit test beds to study wireless sensor networks (WSNs. Consequently, simulation becomes an essential tool to evaluate such systems.We present the power aware wireless sensors (PAWiS simulation framework that supports design and simulation of wireless sensor networks and nodes. The framework emphasizes power consumption capturing and hence the identification of inefficiencies in various hardware and software modules of the systems. These modules include all layers of the communication system, the targeted class of application itself, the power supply and energy management, the central processing unit (CPU, and the sensor-actuator interface. The modular design makes it possible to simulate heterogeneous systems. PAWiS is an OMNeT++ based discrete event simulator written in C++. It captures the node internals (modules as well as the node surroundings (network, environment and provides specific features critical to WSNs like capturing power consumption at various levels of granularity, support for mobility, and environmental dynamics as well as the simulation of timing effects. A module library with standardized interfaces and a power analysis tool have been developed to support the design and analysis of simulation models. The performance of the PAWiS simulator is comparable with other simulation environments.

  17. Modeling and simulation of TDI CMOS image sensors

    Science.gov (United States)

    Nie, Kai-ming; Yao, Su-ying; Xu, Jiang-tao; Gao, Jing

    2013-09-01

    In this paper, a mathematical model of TDI CMOS image sensors was established in behavioral level through MATLAB based on the principle of a TDI CMOS image sensor using temporal oversampling rolling shutter in the along-track direction. The geometric perspective and light energy transmission relationships between the scene and the image on the sensor are included in the proposed model. A graphical user interface (GUI) of the model was also established. A high resolution satellitic picture was used to model the virtual scene being photographed. The effectiveness of the proposed model was verified by computer simulations based on the satellitic picture. In order to guide the design of TDI CMOS image sensors, the impacts of some parameters of TDI CMOS image sensors including pixel pitch, pixel photosensitive size, and integration time on the performance of the sensors were researched through the proposed model. The impacts of the above parameters on the sensors were quantified by sensor's modulation transfer function (MTF) of the along-track direction, which was calculated by slanted-edge method. The simulation results indicated that the TDI CMOS image sensor can get a better performance with smaller pixel photosensitive size and shorter integration time. The proposed model is useful in the process of researching and developing a TDI CMOS image sensor.

  18. Automated Ortho-Rectification of UAV-Based Hyperspectral Data over an Agricultural Field Using Frame RGB Imagery

    Directory of Open Access Journals (Sweden)

    Ayman Habib

    2016-09-01

    Full Text Available Low-cost Unmanned Airborne Vehicles (UAVs equipped with consumer-grade imaging systems have emerged as a potential remote sensing platform that could satisfy the needs of a wide range of civilian applications. Among these applications, UAV-based agricultural mapping and monitoring have attracted significant attention from both the research and professional communities. The interest in UAV-based remote sensing for agricultural management is motivated by the need to maximize crop yield. Remote sensing-based crop yield prediction and estimation are primarily based on imaging systems with different spectral coverage and resolution (e.g., RGB and hyperspectral imaging systems. Due to the data volume, RGB imaging is based on frame cameras, while hyperspectral sensors are primarily push-broom scanners. To cope with the limited endurance and payload constraints of low-cost UAVs, the agricultural research and professional communities have to rely on consumer-grade and light-weight sensors. However, the geometric fidelity of derived information from push-broom hyperspectral scanners is quite sensitive to the available position and orientation established through a direct geo-referencing unit onboard the imaging platform (i.e., an integrated Global Navigation Satellite System (GNSS and Inertial Navigation System (INS. This paper presents an automated framework for the integration of frame RGB images, push-broom hyperspectral scanner data and consumer-grade GNSS/INS navigation data for accurate geometric rectification of the hyperspectral scenes. The approach relies on utilizing the navigation data, together with a modified Speeded-Up Robust Feature (SURF detector and descriptor, for automating the identification of conjugate features in the RGB and hyperspectral imagery. The SURF modification takes into consideration the available direct geo-referencing information to improve the reliability of the matching procedure in the presence of repetitive texture

  19. A UAV-Based Fog Collector Design for Fine-Scale Aerobiological Sampling

    Science.gov (United States)

    Gentry, D.; Guarro, M.; Demachkie, I. S.; Stumfall, I.; Dahlgren, R. P.

    2016-12-01

    Airborne microbes are found throughout the troposphere and into the stratosphere. Knowing how the activity of airborne microorganisms can alter water, carbon, and other geochemical cycles is vital to a full understanding of local and global ecosystems. Just as on the land or in the ocean, atmospheric regions vary in habitability; the underlying geochemical, climatic, and ecological dynamics must be characterized at different scales to be effectively modeled. Most aerobiological studies have focused on a high level: 'How high are airborne microbes found?' and 'How far can they travel?' Most fog and cloud water studies collect from stationary ground stations (point) or along flight transects (1D). To complement and provide context for this data, we have designed a UAV-based modified fog and cloud water collector to retrieve 4D-resolved samples for biological and chemical analysis. Our design uses a passive impacting collector hanging from a rigid rod suspended between two multi-rotor UAVs. The suspension design reduces the effect of turbulence and potential for contamination from the UAV downwash. The UAVs are currently modeled in a leader-follower configuration, taking advantage of recent advances in modular UAVs, UAV swarming, and flight planning. The collector itself is a hydrophobic mesh. Materials including Tyvek, PTFE, nylon, and polypropylene monofilament fabricated via laser cutting, CNC knife, or 3D printing were characterized for droplet collection efficiency using a benchtop atomizer and particle counter. Because the meshes can be easily and inexpensively fabricated, a set can be pre-sterilized and brought to the field for 'hot swapping' to decrease cross-contamination between flight sessions or use as negative controls. An onboard sensor and logging system records the time and location of each sample; when combined with flight tracking data, the samples can be resolved into a 4D volumetric map of the fog bank. Collected samples can be returned to the lab

  20. A UAV-Based Fog Collector Design for Fine-Scale Aerobiological Sampling

    Science.gov (United States)

    Gentry, Diana; Guarro, Marcello; Demachkie, Isabella Siham; Stumfall, Isabel; Dahlgren, Robert P.

    2017-01-01

    Airborne microbes are found throughout the troposphere and into the stratosphere. Knowing how the activity of airborne microorganisms can alter water, carbon, and other geochemical cycles is vital to a full understanding of local and global ecosystems. Just as on the land or in the ocean, atmospheric regions vary in habitability; the underlying geochemical, climatic, and ecological dynamics must be characterized at different scales to be effectively modeled. Most aerobiological studies have focused on a high level: 'How high are airborne microbes found?' and 'How far can they travel?' Most fog and cloud water studies collect from stationary ground stations (point) or along flight transects (1D). To complement and provide context for this data, we have designed a UAV-based modified fog and cloud water collector to retrieve 4D-resolved samples for biological and chemical analysis.Our design uses a passive impacting collector hanging from a rigid rod suspended between two multi-rotor UAVs. The suspension design reduces the effect of turbulence and potential for contamination from the UAV downwash. The UAVs are currently modeled in a leader-follower configuration, taking advantage of recent advances in modular UAVs, UAV swarming, and flight planning.The collector itself is a hydrophobic mesh. Materials including Tyvek, PTFE, nylon, and polypropylene monofilament fabricated via laser cutting, CNC knife, or 3D printing were characterized for droplet collection efficiency using a benchtop atomizer and particle counter. Because the meshes can be easily and inexpensively fabricated, a set can be pre-sterilized and brought to the field for 'hot swapping' to decrease cross-contamination between flight sessions or use as negative controls.An onboard sensor and logging system records the time and location of each sample; when combined with flight tracking data, the samples can be resolved into a 4D volumetric map of the fog bank. Collected samples can be returned to the lab for

  1. UAV based mapping of variation in grassland yield for forage production in Arctic environments

    Science.gov (United States)

    Davids, C.; Karlsen, S. R.; Jørgensen, M.; Ancin Murguzur, F. J.

    2017-12-01

    Grassland cultivation for animal feed is the key agricultural activity in northern Norway. Even though the growing season has increased by at least a week in the last 30 years, grassland yields appear to have declined, probably due to more challenging winter conditions and changing agronomy practices. The ability for local and regional crop productivity forecasting would assist farmers with management decisions and would provide local and national authorities with a better overview over productivity and potential problems due to e.g. winter damage. Remote sensing technology has long been used to estimate and map the variability of various biophysical parameters, but calibration is important. In order to establish the relationship between spectral reflectance and grass yield in northern European environments we combine Sentinel-2 time series, UAV-based multispectral measurements, and ground-based spectroradiometry, with biomass analyses and observations of species composition. In this presentation we will focus on the results from the UAV data acquisition. We used a multirotor UAV with different sensors (a multispectral Rikola camera, and NDVI and RGB cameras) to image a number of cultivated grasslands of different age and productivity in northern Norway in June/July 2016 and 2017. Following UAV data acquisition, 10 to 20 in situ measurements were made per field using a FieldSpec3 (350-2500 nm). In addition, samples were taken to determine biomass and grass species composition. The imaging and sampling was done immediately prior to harvesting. The Rikola camera, when used as a stand-alone camera mounted on a UAV, can collect 15 bands with a spectral width of 10-15 nm in the range between 500-890 nm. In the initial analysis of the 2016 data we investigated how well different vegetation indices correlated with biomass and showed that vegetation indices that include red edge bands perform better than widely used indices such as NDVI. We will extend the analysis with

  2. UAV-based landslide deformation monitoring - first results from Corvara landslide

    Science.gov (United States)

    Thiebes, Benni; Tomelleri, Enrico; Mejia-Aguilar, Abraham; Schlögel, Romy; Darvishi, Mehdi; Remondino, Fabio; Toschi, Isabella; Rutzinger, Martin; Zieher, Thomas

    2016-04-01

    In recent years, unmanned aerial vehicles (UAVs) have been more frequently utilised to study geomorphological and natural hazard processes, including gravitational mass movements such as landslides. UAVs can be equipped with different sensors, e.g. photo cameras and laser scanners, and the data that can be achieved can substantially improve the monitoring and understanding of the involved natural processes. One of the main advantages of UAVs is their flexibility that allows for carrying out assessments of large areas in short periods of time and at much lower costs than other platforms, e.g. airplanes or helicopters. Thereby, UAVs represent an interesting technique to complement more traditional monitoring methods. Here we present some first results of the EUREGIO-funded LEMONADE project that is concerned with the combination and integration of novel and traditional landslide monitoring techniques. We carried out a series of UAV flights over a particularly active part of the Corvara landslide and acquired aerial imagery for quantitative assessments of the retrogressive enlargement of the landslide over recent years. Additional field surveys including terrestrial laser scanning, and UAV-based photogrammetry and laser scanning are scheduled for summer 2016. The Corvara landslide is a large complex earthflow in the Italian Dolomites that has been investigated by a wide range of methodologies over the past years. The landslide is characterised by movement patterns of greatly varying magnitude, ranging from annual rates of a few cm to more than 20 m. The current and past monitoring activities concentrated on GPS measurements as well as multi-temporal differential radar interferometry utilising artificial corner reflectors. Thereby, primarily punctual displacement data were achieved and spatial information on topographic and geomorphic changes were consequently sparse. For our photogrammetry study, we utilised a SoLeon octocopter equipped with a Ricoh GR 16.2 Megapixels

  3. CALCULATION OF PROPELLER UAV BASED REYNOLDS NUMBER AND DEGREE OF REDUCTION

    Directory of Open Access Journals (Sweden)

    O. V. Gerasimov

    2014-01-01

    Full Text Available Presented methodology to the design and check calculations of an isolated propeller for mini-UAV based on the vortex theory of Zhukovsky. Results of the calculation of propeller mini-UAVs and their comparison with results matching propeller on a normal chart. Shows the effect of Re, as well as the degree of reduction in the aerodynamic and geometric characteristics of the propeller.

  4. Distributed Sensor Network Software Development Testing through Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, Sean M. [Univ. of New Mexico, Albuquerque, NM (United States)

    2003-12-01

    The distributed sensor network (DSN) presents a novel and highly complex computing platform with dif culties and opportunities that are just beginning to be explored. The potential of sensor networks extends from monitoring for threat reduction, to conducting instant and remote inventories, to ecological surveys. Developing and testing for robust and scalable applications is currently practiced almost exclusively in hardware. The Distributed Sensors Simulator (DSS) is an infrastructure that allows the user to debug and test software for DSNs independent of hardware constraints. The exibility of DSS allows developers and researchers to investigate topological, phenomenological, networking, robustness and scaling issues, to explore arbitrary algorithms for distributed sensors, and to defeat those algorithms through simulated failure. The user speci es the topology, the environment, the application, and any number of arbitrary failures; DSS provides the virtual environmental embedding.

  5. UAV-based photogrammetry: monitoring of a building zone

    Science.gov (United States)

    Unger, J.; Reich, M.; Heipke, C.

    2014-06-01

    The use of small-size unmanned aerial vehicles (UAV) for civil applications in many different fields such as archaeology, disaster monitoring, aerial surveying or mapping has significantly increased in recent years. The high flexibility and the low cost per acquired information compared to classical systems - terrestrial or aerial - offer a high variety of different applications. This paper addresses the photogrammetric analysis of a monitoring project and gives an insight into the potential of UAV using low cost sensors and present-day processing software. The area of interest is the "zero:e-park", a building zone of zero emission housing in Hannover, Germany, that we monitored in three different epochs over a period of five months. We show that we can derive three dimensional information with an accuracy of a few centimetres. Changes during the epochs, also small ones like the dismantling of scaffolding can be detected. We also depict the limitations of the DEM generation approach which occur at sharp edges and height jumps as well as repetitive structure. Additionally, we compare two different commercial software packages which reveals that some systematic errors still remain in the results.

  6. UAV-based photogrammetry: monitoring of a building zone

    Directory of Open Access Journals (Sweden)

    J. Unger

    2014-06-01

    Full Text Available The use of small-size unmanned aerial vehicles (UAV for civil applications in many different fields such as archaeology, disaster monitoring, aerial surveying or mapping has significantly increased in recent years. The high flexibility and the low cost per acquired information compared to classical systems – terrestrial or aerial – offer a high variety of different applications. This paper addresses the photogrammetric analysis of a monitoring project and gives an insight into the potential of UAV using low cost sensors and present-day processing software. The area of interest is the "zero:e-park", a building zone of zero emission housing in Hannover, Germany, that we monitored in three different epochs over a period of five months. We show that we can derive three dimensional information with an accuracy of a few centimetres. Changes during the epochs, also small ones like the dismantling of scaffolding can be detected. We also depict the limitations of the DEM generation approach which occur at sharp edges and height jumps as well as repetitive structure. Additionally, we compare two different commercial software packages which reveals that some systematic errors still remain in the results.

  7. Design, modeling, and simulation of MEMS pressure sensors

    Science.gov (United States)

    Geca, Mateusz; Kociubiński, Andrzej

    2013-10-01

    This paper focuses on the design and analysis of a MEMS piezoresistive pressure sensor. The absolute pressure sensor with a 150μm wide and 3μm thick silicon membrane is modeled and simulated using CoventorWare™ softwareprofiting from a finite element method (FEM) implemented to determine specific electro-mechanical parameter values characterizing MEMS structure being designed. Optimization of piezoresistor parameters has been also performed to determine optimum dimensions of piezoresistors and their location referred to the center on the pressure sensor diaphragm. The output voltage measured on a piezoresistive Wheatstone bridge has been obtained and compared for two different resistor materials along with and linearity error analysis.

  8. Simulations of piezoelectric pressure sensor for radial artery pulse measurement

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Abhay B. [Department of Electronic Science, University of Pune, Pune 411 007 (India); Kalange, Ashok E. [Department of Electronic Science, University of Pune, Pune 411 007 (India); Tuljaram Chaturchand College, Baramati 413 102 (India); Bodas, Dhananjay, E-mail: dhananjay.bodas@gmail.co [Center for Nanobio Sciences, Agharkar Research Institute, Pune 411 004 (India); Gangal, S.A. [Department of Electronic Science, University of Pune, Pune 411 007 (India)

    2010-04-15

    A radial artery pulse is used to diagnose human body constitution (Prakruti) in Ayurveda. A system consisting of piezoelectric sensor (22 mm x 12 mm), data acquisition card and LabView software was used to record the pulse data. The pulse obtained from the sensor was noisy, even though signal processing was done. Moreover due to large sized senor accurate measurements were not possible. Hence, a need was felt to develop a sensor of the size of the order of finger tip with a resonant frequency of the order of 1 Hz. A micromachined pressure sensor based on piezoelectric sensing mechanism was designed and simulated using CoventorWare. Simulations were carried out by varying dimensions of the sensor to optimize the resonant frequency, stresses and voltage generated as a function of applied pressure. All simulations were done with pressure ranging of 1-30 kPa, which is the range used by Ayurvedic practitioners for diagnosis. Preliminary work on fabrication of such a sensor was carried out successfully.

  9. A Detailed Simulation of the CMS Pixel Sensor

    CERN Document Server

    Swartz, Morris

    2002-01-01

    This note describes a detailed simulation of pixel sensors called PIXELAV. It is not fast and is not intended as a replacement for the CMSIM/OSCAR pixel simulation but rather as a partial replacement for the test beam. It incorporates much of the currently known physics of charge deposition and transport in silicon. Some additional test beam data are still necessary to validate the simulation and to verify that the electronics works as designed, but hopefully, the simulation will reduce our reliance upon (expensive) test beam running. The simulation is intended to aid in: the fine-tuning of the pixel system design; the development of more realistic reconstruction algorithms; the tuning of the fast simulation to more accurately model the physical pixel system; and perhaps most importantly, the continuing calibration of the charge-sharing functions (needed for simulation and reconstruc tion) as detector is radiation damaged during operation. The simulation is already contributing to many of these goals. It give...

  10. Software as a service approach to sensor simulation software deployment

    Science.gov (United States)

    Webster, Steven; Miller, Gordon; Mayott, Gregory

    2012-05-01

    Traditionally, military simulation has been problem domain specific. Executing an exercise currently requires multiple simulation software providers to specialize, deploy, and configure their respective implementations, integrate the collection of software to achieve a specific system behavior, and then execute for the purpose at hand. This approach leads to rigid system integrations which require simulation expertise for each deployment due to changes in location, hardware, and software. Our alternative is Software as a Service (SaaS) predicated on the virtualization of Night Vision Electronic Sensors (NVESD) sensor simulations as an exemplary case. Management middleware elements layer self provisioning, configuration, and integration services onto the virtualized sensors to present a system of services at run time. Given an Infrastructure as a Service (IaaS) environment, enabled and managed system of simulations yields a durable SaaS delivery without requiring user simulation expertise. Persistent SaaS simulations would provide on demand availability to connected users, decrease integration costs and timelines, and benefit the domain community from immediate deployment of lessons learned.

  11. Sensor-scheduling simulation of disparate sensors for Space Situational Awareness

    Science.gov (United States)

    Hobson, T.; Clarkson, I.

    2011-09-01

    The art and science of space situational awareness (SSA) has been practised and developed from the time of Sputnik. However, recent developments, such as the accelerating pace of satellite launch, the proliferation of launch capable agencies, both commercial and sovereign, and recent well-publicised collisions involving man-made space objects, has further magnified the importance of timely and accurate SSA. The United States Strategic Command (USSTRATCOM) operates the Space Surveillance Network (SSN), a global network of sensors tasked with maintaining SSA. The rapidly increasing number of resident space objects will require commensurate improvements in the SSN. Sensors are scarce resources that must be scheduled judiciously to obtain measurements of maximum utility. Improvements in sensor scheduling and fusion, can serve to reduce the number of additional sensors that may be required. Recently, Hill et al. [1] have proposed and developed a simulation environment named TASMAN (Tasking Autonomous Sensors in a Multiple Application Network) to enable testing of alternative scheduling strategies within a simulated multi-sensor, multi-target environment. TASMAN simulates a high-fidelity, hardware-in-the-loop system by running multiple machines with different roles in parallel. At present, TASMAN is limited to simulations involving electro-optic sensors. Its high fidelity is at once a feature and a limitation, since supercomputing is required to run simulations of appreciable scale. In this paper, we describe an alternative, modular and scalable SSA simulation system that can extend the work of Hill et al with reduced complexity, albeit also with reduced fidelity. The tool has been developed in MATLAB and therefore can be run on a very wide range of computing platforms. It can also make use of MATLAB’s parallel processing capabilities to obtain considerable speed-up. The speed and flexibility so obtained can be used to quickly test scheduling algorithms even with a

  12. Simulator of a fail detector system for redundant sensors

    International Nuclear Information System (INIS)

    Assumpcao Filho, E.O.; Nakata, H.

    1990-01-01

    A failure detection and isolation system (FDI) simulation program has been developed for IBM-PC microcomputers. The program, based on the sequencial likelihood ratio testing method developed by A. Wald, was implemented with Monte-Carlo technique. The calculated failure detection rate was favorably compared against the wind-tunnel experimental redundant temperature sensors. (author)

  13. Flexible carbon nanotube sensors for nerve agent simulants

    Science.gov (United States)

    Cattanach, Kyle; Kulkarni, Rashmi D.; Kozlov, Mikhail; Manohar, Sanjeev K.

    2006-08-01

    Chemiresistor-based vapour sensors made from network films of single-walled carbon nanotube (SWNT) bundles on flexible plastic substrates (polyethylene terephthalate, PET) can be used to detect chemical warfare agent simulants for the nerve agents Sarin (diisopropyl methylphosphonate, DIMP) and Soman (dimethyl methylphosphonate, DMMP). Large, reproducible resistance changes (75-150%), are observed upon exposure to DIMP or DMMP vapours, and concentrations as low as 25 ppm can be detected. Robust sensor response to simulant vapours is observed even in the presence of large equilibrium concentrations of interferent vapours commonly found in battle-space environments, such as hexane, xylene and water (10 000 ppm each), suggesting that both DIMP and DMMP vapours are capable of selectively displacing other vapours from the walls of the SWNTs. Response to these interferent vapours can be effectively filtered out by using a 2 µm thick barrier film of the chemoselective polymer polyisobutylene (PIB) on the SWNT surface. These network films are composed of a 1-2 µm thick non-woven mesh of SWNT bundles (15-30 nm diameter), whose sensor response is qualitatively and quantitatively different from previous studies on individual SWNTs, or a network of individual SWNTs, suggesting that vapour sorption at interbundle sites could be playing an important role. This study also shows that the line patterning method used in device fabrication to obtain any desired pattern of films of SWNTs on flexible substrates can be used to rapidly screen simulants at high concentrations before developing more complicated sensor systems.

  14. Rain Simulation for the Test of Automotive Surround Sensors

    Science.gov (United States)

    Hasirlioglu, Sinan; Riener, Andreas; Doric, Igor

    2017-04-01

    The WHO Global Health Observatory data indicates that over 1.25 million people die in traffic accidents annually. To save lives, car manufacturers spend lot of efforts on the development of novel safety systems aiming to avoid or mitigate accidents and provide maximum protection for vehicle occupants as well as vulnerable road users. All the safety features mainly rely on data from surround sensors such as radar, lidar and camera and intelligent vehicles today use these environmental data for instant decision making and vehicle control. As already small errors in sensor data measurements could lead to catastrophes like major injuries or road traffic fatalities, it is of utmost importance to ensure high reliability and accuracy of sensors and safety systems. This work focuses on the influence of environmental factors such as rain conditions, as it is known that rain drops scatter the electromagnetic waves. The result is incorrect measurements with a direct negative impact on environment detection. To identify potential problems of sensors under varying environmental conditions, systems are today tested in real-world settings with two main problems: First, tests are time-consuming and second, environmental conditions are not reproducible. Our approach to test the influence of weather on automotive sensors is to use an indoor rain simulator. Our artificial rain maker, installed at CARISSMA (Center of Automotive Research on Integrated Safety Systems and Measurement Area), is parametrized with rain characteristics measured in the field using a standard disdrometer. System behavior on artificial rain is compared and validated with natural rainfall. With this simulator it is finally possible to test environmental influence at various levels and under reproducible conditions. This saves lot of efforts required for the test process itself and furthermore has a positive impact on the reliability of sensor systems due to the fact that test driven development is enabled.

  15. Graphical user interface for wireless sensor networks simulator

    Science.gov (United States)

    Paczesny, Tomasz; Paczesny, Daniel; Weremczuk, Jerzy

    2008-01-01

    Wireless Sensor Networks (WSN) are currently very popular area of development. It can be suited in many applications form military through environment monitoring, healthcare, home automation and others. Those networks, when working in dynamic, ad-hoc model, need effective protocols which must differ from common computer networks algorithms. Research on those protocols would be difficult without simulation tool, because real applications often use many nodes and tests on such a big networks take much effort and costs. The paper presents Graphical User Interface (GUI) for simulator which is dedicated for WSN studies, especially in routing and data link protocols evaluation.

  16. Underwater Electromagnetic Sensor Networks, Part II: Localization and Network Simulations

    Directory of Open Access Journals (Sweden)

    Javier Zazo

    2016-12-01

    Full Text Available In the first part of the paper, we modeled and characterized the underwater radio channel in shallowwaters. In the second part,we analyze the application requirements for an underwaterwireless sensor network (U-WSN operating in the same environment and perform detailed simulations. We consider two localization applications, namely self-localization and navigation aid, and propose algorithms that work well under the specific constraints associated with U-WSN, namely low connectivity, low data rates and high packet loss probability. We propose an algorithm where the sensor nodes collaboratively estimate their unknown positions in the network using a low number of anchor nodes and distance measurements from the underwater channel. Once the network has been self-located, we consider a node estimating its position for underwater navigation communicating with neighboring nodes. We also propose a communication system and simulate the whole electromagnetic U-WSN in the Castalia simulator to evaluate the network performance, including propagation impairments (e.g., noise, interference, radio parameters (e.g., modulation scheme, bandwidth, transmit power, hardware limitations (e.g., clock drift, transmission buffer and complete MAC and routing protocols. We also explain the changes that have to be done to Castalia in order to perform the simulations. In addition, we propose a parametric model of the communication channel that matches well with the results from the first part of this paper. Finally, we provide simulation results for some illustrative scenarios.

  17. Flexible carbon nanotube sensors for nerve agent simulants

    International Nuclear Information System (INIS)

    Cattanach, Kyle; Kulkarni, Rashmi D; Kozlov, Mikhail; Manohar, Sanjeev K

    2006-01-01

    Chemiresistor-based vapour sensors made from network films of single-walled carbon nanotube (SWNT) bundles on flexible plastic substrates (polyethylene terephthalate, PET) can be used to detect chemical warfare agent simulants for the nerve agents Sarin (diisopropyl methylphosphonate, DIMP) and Soman (dimethyl methylphosphonate, DMMP). Large, reproducible resistance changes (75-150%), are observed upon exposure to DIMP or DMMP vapours, and concentrations as low as 25 ppm can be detected. Robust sensor response to simulant vapours is observed even in the presence of large equilibrium concentrations of interferent vapours commonly found in battle-space environments, such as hexane, xylene and water (10 000 ppm each), suggesting that both DIMP and DMMP vapours are capable of selectively displacing other vapours from the walls of the SWNTs. Response to these interferent vapours can be effectively filtered out by using a 2 μm thick barrier film of the chemoselective polymer polyisobutylene (PIB) on the SWNT surface. These network films are composed of a 1-2 μm thick non-woven mesh of SWNT bundles (15-30 nm diameter), whose sensor response is qualitatively and quantitatively different from previous studies on individual SWNTs, or a network of individual SWNTs, suggesting that vapour sorption at interbundle sites could be playing an important role. This study also shows that the line patterning method used in device fabrication to obtain any desired pattern of films of SWNTs on flexible substrates can be used to rapidly screen simulants at high concentrations before developing more complicated sensor systems

  18. Automated geographic registration and radiometric correction for UAV-based mosaics

    Science.gov (United States)

    Thomasson, J. Alex; Shi, Yeyin; Sima, Chao; Yang, Chenghai; Cope, Dale A.

    2017-05-01

    Texas A and M University has been operating a large-scale, UAV-based, agricultural remote-sensing research project since 2015. To use UAV-based images in agricultural production, many high-resolution images must be mosaicked together to create an image of an agricultural field. Two key difficulties to science-based utilization of such mosaics are geographic registration and radiometric calibration. In our current research project, image files are taken to the computer laboratory after the flight, and semi-manual pre-processing is implemented on the raw image data, including ortho-mosaicking and radiometric calibration. Ground control points (GCPs) are critical for high-quality geographic registration of images during mosaicking. Applications requiring accurate reflectance data also require radiometric-calibration references so that reflectance values of image objects can be calculated. We have developed a method for automated geographic registration and radiometric correction with targets that are installed semi-permanently at distributed locations around fields. The targets are a combination of black (≍5% reflectance), dark gray (≍20% reflectance), and light gray (≍40% reflectance) sections that provide for a transformation of pixel-value to reflectance in the dynamic range of crop fields. The exact spectral reflectance of each target is known, having been measured with a spectrophotometer. At the time of installation, each target is measured for position with a real-time kinematic GPS receiver to give its precise latitude and longitude. Automated location of the reference targets in the images is required for precise, automated, geographic registration; and automated calculation of the digital-number to reflectance transformation is required for automated radiometric calibration. To validate the system for radiometric calibration, a calibrated UAV-based image mosaic of a field was compared to a calibrated single image from a manned aircraft. Reflectance

  19. Simulation and optimization of silicon-on-sapphire pressure sensor

    Science.gov (United States)

    Kulesh, N. A.; Kudyukov, E. V.; Balymov, K. G.; Beloyshov, A. A.

    2017-09-01

    In this paper, finite element analysis software COMSOL Multiphysics was used to simulate the performance of silicon-on-sapphire piezoresistive pressure sensor, aiming to elaborate a flexible model suitable for further optimization and customization of the currently produced pressure sensors. The base model was built around the cylindrical pressure cell made of titanium alloy having a circular diaphragm with monocrystalline sapphire layer attached. The monocrystalline piezoresistive elements were placed on top of the double-layer diaphragm and electrically connected to form the Wheatstone bridge. Verification of the model and parametric study included three main areas: geometrical parameters of the cell, position of the elements on the diaphragm, and operation at elevated temperature. Optimization of the cell geometry included variation of bossed titanium diaphragm parameters as well as rounding-off radiuses near the edges of the diaphragm. Influence of the temperature was considered separately for thermal expansion of the mechanical components and for the changes of electrical and piezoresistive properties of the piezoresistive elements. In conclusion, the simulation results were compared to the experimental data obtained for three different constructions of the commercial pressure sensors produced by SPA of Automatics named after Academician N.A. Semikhatov.

  20. OPEN SOURCE IMAGE-PROCESSING TOOLS FOR LOW-COST UAV-BASED LANDSLIDE INVESTIGATIONS

    Directory of Open Access Journals (Sweden)

    U. Niethammer

    2012-09-01

    Full Text Available In recent years, the application of unmanned aerial vehicles (UAVs has become more common and the availability of lightweight digital cameras has enabled UAV-systems to represent affordable and practical remote sensing platforms, allowing flexible and high- resolution remote sensing investigations. In the course of numerous UAV-based remote sensing campaigns significant numbers of airborne photographs of two different landslides have been acquired. These images were used for ortho-mosaic and digital terrain model (DTM generation, thus allowing for high-resolution landslide monitoring. Several new open source image- and DTM- processing tools are now providing a complete remote sensing working cycle with the use of no commercial hard- or software.

  1. Assessing Biodiversity in Boreal Forests with UAV-Based Photogrammetric Point Clouds and Hyperspectral Imaging

    Directory of Open Access Journals (Sweden)

    Ninni Saarinen

    2018-02-01

    Full Text Available Forests are the most diverse terrestrial ecosystems and their biological diversity includes trees, but also other plants, animals, and micro-organisms. One-third of the forested land is in boreal zone; therefore, changes in biological diversity in boreal forests can shape biodiversity, even at global scale. Several forest attributes, including size variability, amount of dead wood, and tree species richness, can be applied in assessing biodiversity of a forest ecosystem. Remote sensing offers complimentary tool for traditional field measurements in mapping and monitoring forest biodiversity. Recent development of small unmanned aerial vehicles (UAVs enable the detailed characterization of forest ecosystems through providing data with high spatial but also temporal resolution at reasonable costs. The objective here is to deepen the knowledge about assessment of plot-level biodiversity indicators in boreal forests with hyperspectral imagery and photogrammetric point clouds from a UAV. We applied individual tree crown approach (ITC and semi-individual tree crown approach (semi-ITC in estimating plot-level biodiversity indicators. Structural metrics from the photogrammetric point clouds were used together with either spectral features or vegetation indices derived from hyperspectral imagery. Biodiversity indicators like the amount of dead wood and species richness were mainly underestimated with UAV-based hyperspectral imagery and photogrammetric point clouds. Indicators of structural variability (i.e., standard deviation in diameter-at-breast height and tree height were the most accurately estimated biodiversity indicators with relative RMSE between 24.4% and 29.3% with semi-ITC. The largest relative errors occurred for predicting deciduous trees (especially aspen and alder, partly due to their small amount within the study area. Thus, especially the structural diversity was reliably predicted by integrating the three-dimensional and spectral

  2. Some technical notes on using UAV-based remote sensing for post disaster assessment

    Science.gov (United States)

    Rokhmana, Catur Aries; Andaru, Ruli

    2017-07-01

    Indonesia is located in an area prone to disasters, which are various kinds of natural disasters happen. In disaster management, the geoinformation data are needed to be able to evaluate the impact area. The UAV (Unmanned Aerial Vehicle)-Based remote sensing technology is a good choice to produce a high spatial resolution of less than 15 cm, while the current resolution of the satellite imagery is still greater than 50 cm. This paper shows some technical notes that should be considered when using UAV-Based remote sensing system in post disaster for rapid assessment. Some cases are Aceh Earthquake in years 2013 for seeing infrastructure damages, Banjarnegara landslide in year 2014 for seeing the impact; and Kelud volcano eruption in year 2014 for seeing the impact and volumetric material calculation. The UAV-Based remote sensing system should be able to produce the Orthophoto image that can provide capabilities for visual interpretation the individual damage objects, and the changes situation. Meanwhile the DEM (digital Elevation model) product can derive terrain topography, and volumetric calculation with accuracy 3-5 pixel or sub-meter also. The UAV platform should be able for working remotely and autonomously in dangerous area and limited infrastructures. In mountainous or volcano area, an unconventional flight plan should implemented. Unfortunately, not all impact can be seen from above such as wall crack, some parcel boundaries, and many objects that covered by others higher object. The previous existing geoinformation data are also needed to be able to evaluate the change detection automatically.

  3. Simulation of Attacks for Security in Wireless Sensor Network.

    Science.gov (United States)

    Diaz, Alvaro; Sanchez, Pablo

    2016-11-18

    The increasing complexity and low-power constraints of current Wireless Sensor Networks (WSN) require efficient methodologies for network simulation and embedded software performance analysis of nodes. In addition, security is also a very important feature that has to be addressed in most WSNs, since they may work with sensitive data and operate in hostile unattended environments. In this paper, a methodology for security analysis of Wireless Sensor Networks is presented. The methodology allows designing attack-aware embedded software/firmware or attack countermeasures to provide security in WSNs. The proposed methodology includes attacker modeling and attack simulation with performance analysis (node's software execution time and power consumption estimation). After an analysis of different WSN attack types, an attacker model is proposed. This model defines three different types of attackers that can emulate most WSN attacks. In addition, this paper presents a virtual platform that is able to model the node hardware, embedded software and basic wireless channel features. This virtual simulation analyzes the embedded software behavior and node power consumption while it takes into account the network deployment and topology. Additionally, this simulator integrates the previously mentioned attacker model. Thus, the impact of attacks on power consumption and software behavior/execution-time can be analyzed. This provides developers with essential information about the effects that one or multiple attacks could have on the network, helping them to develop more secure WSN systems. This WSN attack simulator is an essential element of the attack-aware embedded software development methodology that is also introduced in this work.

  4. Simulating Real-Time Aspects of Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Liang Yao

    2010-01-01

    Full Text Available Wireless Sensor Networks (WSNs technology has been mainly used in the applications with low-frequency sampling and little computational complexity. Recently, new classes of WSN-based applications with different characteristics are being considered, including process control, industrial automation and visual surveillance. Such new applications usually involve relatively heavy computations and also present real-time requirements as bounded end-to- end delay and guaranteed Quality of Service. It becomes then necessary to employ proper resource management policies, not only for communication resources but also jointly for computing resources, in the design and development of such WSN-based applications. In this context, simulation can play a critical role, together with analytical models, for validating a system design against the parameters of Quality of Service demanded for. In this paper, we present RTNS, a publicly available free simulation tool which includes Operating System aspects in wireless distributed applications. RTNS extends the well-known NS-2 simulator with models of the CPU, the Real-Time Operating System and the application tasks, to take into account delays due to the computation in addition to the communication. We demonstrate the benefits of RTNS by presenting our simulation study for a complex WSN-based multi-view vision system for real-time event detection.

  5. Analysis of nanowire transistor based nitrogen dioxide gas sensor – A simulation study

    Directory of Open Access Journals (Sweden)

    Gaurav Saxena

    2015-06-01

    Full Text Available Sensors sensitivity, selectivity and stability has always been a prime design concern for gas sensors designers. Modeling and simulation of gas sensors aids the designers in improving their performance. In this paper, different routes for the modeling and simulation of a semiconducting gas sensor is presented. Subsequently, by employing one of the route, the response of Zinc Oxide nanowire transistor towards nitrogen dioxide ambient is simulated. In addition to the sensing mechanism, simulation study of gas species desorption by applying a recovery voltage is also presented.

  6. SIMULATION OF WIRELESS SENSOR NETWORK WITH HYBRID TOPOLOGY

    Directory of Open Access Journals (Sweden)

    J. Jaslin Deva Gifty

    2016-03-01

    Full Text Available The design of low rate Wireless Personal Area Network (WPAN by IEEE 802.15.4 standard has been developed to support lower data rates and low power consuming application. Zigbee Wireless Sensor Network (WSN works on the network and application layer in IEEE 802.15.4. Zigbee network can be configured in star, tree or mesh topology. The performance varies from topology to topology. The performance parameters such as network lifetime, energy consumption, throughput, delay in data delivery and sensor field coverage area varies depending on the network topology. In this paper, designing of hybrid topology by using two possible combinations such as star-tree and star-mesh is simulated to verify the communication reliability. This approach is to combine all the benefits of two network model. The parameters such as jitter, delay and throughput are measured for these scenarios. Further, MAC parameters impact such as beacon order (BO and super frame order (SO for low power consumption and high channel utilization, has been analysed for star, tree and mesh topology in beacon disable mode and beacon enable mode by varying CBR traffic loads.

  7. A debugging method of the Quadrotor UAV based on infrared thermal imaging

    Science.gov (United States)

    Cui, Guangjie; Hao, Qian; Yang, Jianguo; Chen, Lizhi; Hu, Hongkang; Zhang, Lijun

    2018-01-01

    High-performance UAV has been popular and in great need in recent years. The paper introduces a new method in debugging Quadrotor UAVs. Based on the infrared thermal technology and heat transfer theory, a UAV is under debugging above a hot-wire grid which is composed of 14 heated nichrome wires. And the air flow propelled by the rotating rotors has an influence on the temperature distribution of the hot-wire grid. An infrared thermal imager below observes the distribution and gets thermal images of the hot-wire grid. With the assistance of mathematic model and some experiments, the paper discusses the relationship between thermal images and the speed of rotors. By means of getting debugged UAVs into test, the standard information and thermal images can be acquired. The paper demonstrates that comparing to the standard thermal images, a UAV being debugging in the same test can draw some critical data directly or after interpolation. The results are shown in the paper and the advantages are discussed.

  8. UAV-Based Optical Granulometry as Tool for Detecting Changes in Structure of Flood Depositions

    Directory of Open Access Journals (Sweden)

    Jakub Langhammer

    2017-03-01

    Full Text Available This paper presents a new non-invasive technique of granulometric analysis based on the fusion of two imaging techniques, Unmanned Aerial Vehicles (UAV-based photogrammetry and optical digital granulometry. This newly proposed technique produces seamless coverage of a study site in order to analyze the granulometric properties of alluvium and observe its spatiotemporal changes. This proposed technique is tested by observing changes along the point bar of a mid-latitude mountain stream. UAV photogrammetry acquired at a low-level flight altitude (at a height of 8 m is used to acquire ultra-high resolution orthoimages to build high-precision digital terrain models (DTMs. These orthoimages are covered by a regular virtual grid, and the granulometric properties of the grid fields are analyzed using the digital optical granulometric tool BaseGrain. This tested framework demonstrates the applicability of the proposed method for granulometric analysis, which yields accuracy comparable to that of traditional field optical granulometry. The seamless nature of this method further enables researchers to study the spatial distribution of granulometric properties across multiple study sites, as well as to analyze multitemporal changes using repeated imaging.

  9. Using elements of game engine architecture to simulate sensor networks for eldercare.

    Science.gov (United States)

    Godsey, Chad; Skubic, Marjorie

    2009-01-01

    When dealing with a real time sensor network, building test data with a known ground truth is a tedious and cumbersome task. In order to quickly build test data for such a network, a simulation solution is a viable option. Simulation environments have a close relationship with computer game environments, and therefore there is much to be learned from game engine design. In this paper, we present our vision for a simulated in-home sensor network and describe ongoing work on using elements of game engines for building the simulator. Validation results are included to show agreement on motion sensor simulation with the physical environment.

  10. Wireless Power Transfer Protocols in Sensor Networks: Experiments and Simulations

    Directory of Open Access Journals (Sweden)

    Sotiris Nikoletseas

    2017-04-01

    Full Text Available Rapid technological advances in the domain of Wireless Power Transfer pave the way for novel methods for power management in systems of wireless devices, and recent research works have already started considering algorithmic solutions for tackling emerging problems. In this paper, we investigate the problem of efficient and balanced Wireless Power Transfer in Wireless Sensor Networks. We employ wireless chargers that replenish the energy of network nodes. We propose two protocols that configure the activity of the chargers. One protocol performs wireless charging focused on the charging efficiency, while the other aims at proper balance of the chargers’ residual energy. We conduct detailed experiments using real devices and we validate the experimental results via larger scale simulations. We observe that, in both the experimental evaluation and the evaluation through detailed simulations, both protocols achieve their main goals. The Charging Oriented protocol achieves good charging efficiency throughout the experiment, while the Energy Balancing protocol achieves a uniform distribution of energy within the chargers.

  11. A Digital Sensor Simulator of the Pushbroom Offner Hyperspectral Imaging Spectrometer

    Science.gov (United States)

    Tao, Dongxing; Jia, Guorui; Yuan, Yan; Zhao, Huijie

    2014-01-01

    Sensor simulators can be used in forecasting the imaging quality of a new hyperspectral imaging spectrometer, and generating simulated data for the development and validation of the data processing algorithms. This paper presents a novel digital sensor simulator for the pushbroom Offner hyperspectral imaging spectrometer, which is widely used in the hyperspectral remote sensing. Based on the imaging process, the sensor simulator consists of a spatial response module, a spectral response module, and a radiometric response module. In order to enhance the simulation accuracy, spatial interpolation-resampling, which is implemented before the spatial degradation, is developed to compromise the direction error and the extra aliasing effect. Instead of using the spectral response function (SRF), the dispersive imaging characteristics of the Offner convex grating optical system is accurately modeled by its configuration parameters. The non-uniformity characteristics, such as keystone and smile effects, are simulated in the corresponding modules. In this work, the spatial, spectral and radiometric calibration processes are simulated to provide the parameters of modulation transfer function (MTF), SRF and radiometric calibration parameters of the sensor simulator. Some uncertainty factors (the stability, band width of the monochromator for the spectral calibration, and the integrating sphere uncertainty for the radiometric calibration) are considered in the simulation of the calibration process. With the calibration parameters, several experiments were designed to validate the spatial, spectral and radiometric response of the sensor simulator, respectively. The experiment results indicate that the sensor simulator is valid. PMID:25615727

  12. A Digital Sensor Simulator of the Pushbroom Offner Hyperspectral Imaging Spectrometer

    Directory of Open Access Journals (Sweden)

    Dongxing Tao

    2014-12-01

    Full Text Available Sensor simulators can be used in forecasting the imaging quality of a new hyperspectral imaging spectrometer, and generating simulated data for the development and validation of the data processing algorithms. This paper presents a novel digital sensor simulator for the pushbroom Offner hyperspectral imaging spectrometer, which is widely used in the hyperspectral remote sensing. Based on the imaging process, the sensor simulator consists of a spatial response module, a spectral response module, and a radiometric response module. In order to enhance the simulation accuracy, spatial interpolation-resampling, which is implemented before the spatial degradation, is developed to compromise the direction error and the extra aliasing effect. Instead of using the spectral response function (SRF, the dispersive imaging characteristics of the Offner convex grating optical system is accurately modeled by its configuration parameters. The non-uniformity characteristics, such as keystone and smile effects, are simulated in the corresponding modules. In this work, the spatial, spectral and radiometric calibration processes are simulated to provide the parameters of modulation transfer function (MTF, SRF and radiometric calibration parameters of the sensor simulator. Some uncertainty factors (the stability, band width of the monochromator for the spectral calibration, and the integrating sphere uncertainty for the radiometric calibration are considered in the simulation of the calibration process. With the calibration parameters, several experiments were designed to validate the spatial, spectral and radiometric response of the sensor simulator, respectively. The experiment results indicate that the sensor simulator is valid.

  13. Fixed-point auto-landing algorithm for UAV based on point tracking

    Science.gov (United States)

    Shao, Zhiyu; Nie, Zhengang; Feng, Yuan; Feng, Shunshan

    2009-12-01

    A new automatic fixed-point landing algorithm for UAV using the instantaneous speed obtained by image sensors and computer vision method is proposed. In the proposed scheme, once the specified land pad for landing is captured, the UAV will switch from auto-seeking mode to landing mode. In the landing mode, the feature point of the prospective zone is extracted and then being tracked. The noise in the motion parameter introduced by the feature point mismatching is reduced by fast iterative least square algorithm, and the accurate instantaneous speed of UAV is obtained. The simulation results show that the proposed algorithm efficiently improve the accuracy of the estimation of instantaneous velocity for the fixed-point landing system of UAV.

  14. Towards a Transferable UAV-Based Framework for River Hydromorphological Characterization

    Directory of Open Access Journals (Sweden)

    Mónica Rivas Casado

    2017-09-01

    Full Text Available The multiple protocols that have been developed to characterize river hydromorphology, partly in response to legislative drivers such as the European Union Water Framework Directive (EU WFD, make the comparison of results obtained in different countries challenging. Recent studies have analyzed the comparability of existing methods, with remote sensing based approaches being proposed as a potential means of harmonizing hydromorphological characterization protocols. However, the resolution achieved by remote sensing products may not be sufficient to assess some of the key hydromorphological features that are required to allow an accurate characterization. Methodologies based on high resolution aerial photography taken from Unmanned Aerial Vehicles (UAVs have been proposed by several authors as potential approaches to overcome these limitations. Here, we explore the applicability of an existing UAV based framework for hydromorphological characterization to three different fluvial settings representing some of the distinct ecoregions defined by the WFD geographical intercalibration groups (GIGs. The framework is based on the automated recognition of hydromorphological features via tested and validated Artificial Neural Networks (ANNs. Results show that the framework is transferable to the Central-Baltic and Mediterranean GIGs with accuracies in feature identification above 70%. Accuracies of 50% are achieved when the framework is implemented in the Very Large Rivers GIG. The framework successfully identified vegetation, deep water, shallow water, riffles, side bars and shadows for the majority of the reaches. However, further algorithm development is required to ensure a wider range of features (e.g., chutes, structures and erosion are accurately identified. This study also highlights the need to develop an objective and fit for purpose hydromorphological characterization framework to be adopted within all EU member states to facilitate comparison

  15. Towards a Transferable UAV-Based Framework for River Hydromorphological Characterization.

    Science.gov (United States)

    Rivas Casado, Mónica; González, Rocío Ballesteros; Ortega, José Fernando; Leinster, Paul; Wright, Ros

    2017-09-26

    The multiple protocols that have been developed to characterize river hydromorphology, partly in response to legislative drivers such as the European Union Water Framework Directive (EU WFD), make the comparison of results obtained in different countries challenging. Recent studies have analyzed the comparability of existing methods, with remote sensing based approaches being proposed as a potential means of harmonizing hydromorphological characterization protocols. However, the resolution achieved by remote sensing products may not be sufficient to assess some of the key hydromorphological features that are required to allow an accurate characterization. Methodologies based on high resolution aerial photography taken from Unmanned Aerial Vehicles (UAVs) have been proposed by several authors as potential approaches to overcome these limitations. Here, we explore the applicability of an existing UAV based framework for hydromorphological characterization to three different fluvial settings representing some of the distinct ecoregions defined by the WFD geographical intercalibration groups (GIGs). The framework is based on the automated recognition of hydromorphological features via tested and validated Artificial Neural Networks (ANNs). Results show that the framework is transferable to the Central-Baltic and Mediterranean GIGs with accuracies in feature identification above 70%. Accuracies of 50% are achieved when the framework is implemented in the Very Large Rivers GIG. The framework successfully identified vegetation, deep water, shallow water, riffles, side bars and shadows for the majority of the reaches. However, further algorithm development is required to ensure a wider range of features (e.g., chutes, structures and erosion) are accurately identified. This study also highlights the need to develop an objective and fit for purpose hydromorphological characterization framework to be adopted within all EU member states to facilitate comparison of results.

  16. Multiplatform Mission Planning and Operations Simulation Environment for Adaptive Remote Sensors

    Science.gov (United States)

    Smith, G.; Ball, C.; O'Brien, A.; Johnson, J. T.

    2017-12-01

    We report on the design and development of mission simulator libraries to support the emerging field of adaptive remote sensors. We will outline the current state of the art in adaptive sensing, provide analysis of how the current approach to performing observing system simulation experiments (OSSEs) must be changed to enable adaptive sensors for remote sensing, and present an architecture to enable their inclusion in future OSSEs.The growing potential of sensors capable of real-time adaptation of their operational parameters calls for a new class of mission planning and simulation tools. Existing simulation tools used in OSSEs assume a fixed set of sensor parameters in terms of observation geometry, frequencies used, resolution, or observation time, which allows simplifications to be made in the simulation and allows sensor observation errors to be characterized a priori. Adaptive sensors may vary these parameters depending on the details of the scene observed, so that sensor performance is not simple to model without conducting OSSE simulations that include sensor adaptation in response to varying observational environment. Adaptive sensors are of significance to resource-constrained, small satellite platforms because they enable the management of power and data volumes while providing methods for multiple sensors to collaborate.The new class of OSSEs required to utilize adaptive sensors located on multiple platforms must answer the question: If the physical act of sensing has a cost, how does the system determine if the science value of a measurement is worth the cost and how should that cost be shared among the collaborating sensors?Here we propose to answer this question using an architecture structured around three modules: ADAPT, MANAGE and COLLABORATE. The ADAPT module is a set of routines to facilitate modeling of adaptive sensors, the MANAGE module will implement a set of routines to facilitate simulations of sensor resource management when power and data

  17. Development of Sensor Based Applications for the Android Platform: an Approach Based on Realistic Simulation

    Directory of Open Access Journals (Sweden)

    Pablo CAMPILLO-SÁNCHEZ

    2013-05-01

    Full Text Available Smart phones are equipped with a wide range of sensors (such as GPS, light, accelerometer, gyroscope, etc. and allow users to be connected everywhere. These characteristics offer a rich information source for creating context-aware applications. However, testing these applications in the lab, before their deployment, could become a hard task or impossible because of sensors correlation, too wide testing area or an excessive number of people involved. This work aims to solve these problems carrying out the testing in a simulator, simulating the world in which the application user is immersed into. Tester controls her avatar and the avatar has a simulated smart phone that is connected with the user’s smart phone. Applications under test are installed on the real smart phone and are compiled with a library that replaces standard services of the sensors by others that offer data sensor from the simulator (depending on the simulated smart phone context instead of real world.

  18. Modeling and simulation of a wheatstone bridge pressure sensor in high temperature with VHDL-AMS

    OpenAIRE

    Baccar, Sahbi; Levi, Timothée; Dallet, Dominique; Barbara, François

    2013-01-01

    International audience; This paper presents a model of a Wheatstone bridge sensor in VHDL-AMS. This model is useful to take into account the temperature effect on the sensor accuracy. The model is developed on the basis of a resistor model. Simulations are performed for three different combinations of parameters values. They confirm the resistors mismatch effect on the sensor accuracy in high temperature (HT).

  19. Mission-Driven sensor management analysis, design, implementation and simulation

    NARCIS (Netherlands)

    Bolderheij, F.

    2007-01-01

    The management of sensors onboard of the vessels operated by the Royal Netherlands Navy is becoming increasingly knowledge intensive due to the fact that these vessels are equipped with state-of-the-art sensor systems that provide more functionality and more accurate information at the cost of more

  20. Experimental Evaluation of Simulation Abstractions for Wireless Sensor Network MAC Protocols

    NARCIS (Netherlands)

    Halkes, G.P.; Langendoen, K.G.

    2010-01-01

    The evaluation ofMAC protocols forWireless Sensor Networks (WSNs) is often performed through simulation. These simulations necessarily abstract away from reality inmany ways. However, the impact of these abstractions on the results of the simulations has received only limited attention. Moreover,

  1. Using UAV-Based Systems to Monitor Air Pollution in Areas with Poor Accessibility

    Directory of Open Access Journals (Sweden)

    Oscar Alvear

    2017-01-01

    Full Text Available Air pollution monitoring has recently become an issue of utmost importance in our society. Despite the fact that crowdsensing approaches could be an adequate solution for urban areas, they cannot be implemented in rural environments. Instead, deploying a fleet of UAVs could be considered an acceptable alternative. Embracing this approach, this paper proposes the use of UAVs equipped with off-the-shelf sensors to perform air pollution monitoring tasks. These UAVs are guided by our proposed Pollution-driven UAV Control (PdUC algorithm, which is based on a chemotaxis metaheuristic and a local particle swarm optimization strategy. Together, they allow automatically performing the monitoring of a specified area using UAVs. Experimental results show that, when using PdUC, an implicit priority guides the construction of pollution maps by focusing on areas where the pollutants’ concentration is higher. This way, accurate maps can be constructed in a faster manner when compared to other strategies. The PdUC scheme is compared against various standard mobility models through simulation, showing that it achieves better performance. In particular, it is able to find the most polluted areas with more accuracy and provides a higher coverage within the time bounds defined by the UAV flight time.

  2. An Expert System And Simulation Approach For Sensor Management & Control In A Distributed Surveillance Network

    Science.gov (United States)

    Leon, Barbara D.; Heller, Paul R.

    1987-05-01

    A surveillance network is a group of multiplatform sensors cooperating to improve network performance. Network control is distributed as a measure to decrease vulnerability to enemy threat. The network may contain diverse sensor types such as radar, ESM (Electronic Support Measures), IRST (Infrared search and track) and E-0 (Electro-Optical). Each platform may contain a single sensor or suite of sensors. In a surveillance network it is desirable to control sensors to make the overall system more effective. This problem has come to be known as sensor management and control (SM&C). Two major facets of network performance are surveillance and survivability. In a netted environment, surveillance can be enhanced if information from all sensors is combined and sensor operating conditions are controlled to provide a synergistic effect. In contrast, when survivability is the main concern for the network, the best operating status for all sensors would be passive or off. Of course, improving survivability tends to degrade surveillance. Hence, the objective of SM&C is to optimize surveillance and survivability of the network. Too voluminous data of various formats and the quick response time are two characteristics of this problem which make it an ideal application for Artificial Intelligence. A solution to the SM&C problem, presented as a computer simulation, will be presented in this paper. The simulation is a hybrid production written in LISP and FORTRAN. It combines the latest conventional computer programming methods with Artificial Intelligence techniques to produce a flexible state-of-the-art tool to evaluate network performance. The event-driven simulation contains environment models coupled with an expert system. These environment models include sensor (track-while-scan and agile beam) and target models, local tracking, and system tracking. These models are used to generate the environment for the sensor management and control expert system. The expert system

  3. Multi-temporal UAV based data for mapping crop type and structure in smallholder dominated Tanzanian agricultural landscape

    Science.gov (United States)

    Nagol, J. R.; Chung, C.; Dempewolf, J.; Maurice, S.; Mbungu, W.; Tumbo, S.

    2015-12-01

    Timely mapping and monitoring of crops like Maize, an important food security crop in Tanzania, can facilitate timely response by government and non-government organizations to food shortage or surplus conditions. Small UAVs can play an important role in linking the spaceborne remote sensing data and ground based measurement to improve the calibration and validation of satellite based estimates of in-season crop metrics. In Tanzania most of the growing season is often obscured by clouds. UAV data, if collected within a stratified statistical sampling framework, can also be used to directly in lieu of spaceborne data to infer mid-season yield estimates at regional scales.Here we present an object based approach to estimate crop metrics like crop type, area, and height using multi-temporal UAV based imagery. The methods were tested at three 1km2 plots in Kilosa, Njombe, and Same districts in Tanzania. At these sites both ground based and UAV based data were collected on a monthly time-step during the year 2015 growing season. SenseFly eBee drone with RGB and NIR-R-G camera was used to collect data. Crop type classification accuracies of above 85% were easily achieved.

  4. Electro-magnetic design and simulation of wall current monitor sensor for LEHIPA

    International Nuclear Information System (INIS)

    Shukla, Hitesh; Kumar, Amit; Singh, S.K.; Dixit, M.Y.; Joshi, Gopal

    2015-01-01

    Beam diagnostic instruments are essential component of any accelerator. Wall current monitors (WCMs) are common beam diagnostic tools used for acquiring the temporal distribution of the charged particle bunches. This paper discusses the electro-magnetic design and simulation results of Wall current Monitor sensor being developed at Electronics Division, BARC with a bandwidth from 16.9 MHz to 30 GHz. As per the simulation results, output of the sensor for a 0.30A peak current bunched beam will be 0.8 Vpeak to peak. The simulations were carried out for Eigen modes, Particle In Cell (PIC) and Wake-field simulations using CST Microwave Studio Suite. (author)

  5. Overview of DOS attacks on wireless sensor networks and experimental results for simulation of interference attacks

    Directory of Open Access Journals (Sweden)

    Željko Gavrić

    2018-01-01

    Full Text Available Wireless sensor networks are now used in various fields. The information transmitted in the wireless sensor networks is very sensitive, so the security issue is very important. DOS (denial of service attacks are a fundamental threat to the functioning of wireless sensor networks. This paper describes some of the most common DOS attacks and potential methods of protection against them. The case study shows one of the most frequent attacks on wireless sensor networks – the interference attack. In the introduction of this paper authors assume that the attack interference can cause significant obstruction of wireless sensor networks. This assumption has been proved in the case study through simulation scenario and simulation results.

  6. Simulation Study of Nano Aqueous Flow Sensor Based on Amperometric Measurement

    Directory of Open Access Journals (Sweden)

    Zhengguo Lou

    2006-04-01

    Full Text Available In this paper, a novel nano aqueous flow sensor which consists of two closelyspaced amperometric sensors is investigated by digital simulation. The simulation resultsindicate that the ratio of the responses of two closely spaced amperometric sensors is onlyrelated to flow rates in the channel, insensitive to the analyte concentration in the solution.By comparing the output of two amperometric sensors, the flow rate in the channel can bededuced. It is not necessary to determine the analyte concentration in advance. Thesimulation results show it is able to detect flow rate by in the range of several nano-liters perminute when the distance between the working electrodes of two amperometric sensors is200 nm and the cross-section of the channel is 1 μm x 1 μm.

  7. Multi-sensor cloud retrieval simulator and remote sensing from model parameters - Part 1: Synthetic sensor radiance formulation

    Science.gov (United States)

    Wind, G.; da Silva, A. M.; Norris, P. M.; Platnick, S.

    2013-11-01

    In this paper we describe a general procedure for calculating synthetic sensor radiances from variable output from a global atmospheric forecast model. In order to take proper account of the discrepancies between model resolution and sensor footprint, the algorithm takes explicit account of the model subgrid variability, in particular its description of the probability density function of total water (vapor and cloud condensate.) The simulated sensor radiances are then substituted into an operational remote sensing algorithm processing chain to produce a variety of remote sensing products that would normally be produced from actual sensor output. This output can then be used for a wide variety of purposes such as model parameter verification, remote sensing algorithm validation, testing of new retrieval methods and future sensor studies. We show a specific implementation using the GEOS-5 model, the MODIS instrument and the MODIS Adaptive Processing System (MODAPS) Data Collection 5.1 operational remote sensing cloud algorithm processing chain (including the cloud mask, cloud top properties and cloud optical and microphysical properties products). We focus on clouds because they are very important to model development and improvement.

  8. Simulation of at-sensor radiance over land for proposed thermal ...

    Indian Academy of Sciences (India)

    simulated and understood pertaining to various land and atmospheric characteristics. A theoreti- cal modelling exercise is carried out with an aim to simulate the at-sensor radiance for the proposed thermal channels of the Imager payload of INSAT-. 3D satellite over the land surfaces using a radiative transfer model (RTM).

  9. TopSPICE Simulations for Temperature Compensation of ISFET/MEMFET Micro-Sensor

    Directory of Open Access Journals (Sweden)

    Sawsen AZZOUZI

    2014-05-01

    Full Text Available In this work, an ISFET (Ion Sensitive Field Effect Transistor/MEMFET (Membrane Field Effect Transistor interface circuit with temperature compensation has been successfully designed and simulated. In each interface, we used the macro-model of ISFET/MEMFET based chemical sensors simulated in TopSPICE. The simulation results of the different sensing circuits of ISFET/MEMFETs for temperature compensation show that the readout configuration for ISFET/MEMFET sensors based on Wheatstone-Bridge connection is the most effective with a temperature drift 5´10-6 mV/°C.

  10. Design optimization of pixel sensors using device simulations for the phase-II CMS tracker upgrade

    Science.gov (United States)

    Jain, G.; Bhardwaj, A.; Dalal, R.; Eber, R.; Eichorn, T.; Fernandez, M.; Lalwani, K.; Messineo, A.; Palomo, F. R.; Peltola, T.; Printz, M.; Ranjan, K.; Villa, I.; Hidalgo, S.; CMS Collaboration

    2016-07-01

    In order to address the problems caused by the harsh radiation environment during the high luminosity phase of the LHC (HL-LHC), all silicon tracking detectors (pixels and strips) in the CMS experiment will undergo an upgrade. And so to develop radiation hard pixel sensors, simulations have been performed using the 2D TCAD device simulator, SILVACO, to obtain design parameters. The effect of various design parameters like pixel size, pixel depth, implant width, metal overhang, p-stop concentration, p-stop depth and bulk doping density on the leakage current and critical electric field are studied for both non-irradiated as well as irradiated pixel sensors. These 2D simulation results of planar pixels are useful for providing insight into the behaviour of non-irradiated and irradiated silicon pixel sensors and further work on 3D simulation is underway.

  11. Design optimization of pixel sensors using device simulations for the phase-II CMS tracker upgrade

    International Nuclear Information System (INIS)

    Jain, G.; Bhardwaj, A.; Dalal, R.; Eber, R.; Eichorn, T.; Fernandez, M.; Lalwani, K.; Messineo, A.; Palomo, F.R.; Peltola, T.; Printz, M.; Ranjan, K.; Villa, I.; Hidalgo, S.

    2016-01-01

    In order to address the problems caused by the harsh radiation environment during the high luminosity phase of the LHC (HL-LHC), all silicon tracking detectors (pixels and strips) in the CMS experiment will undergo an upgrade. And so to develop radiation hard pixel sensors, simulations have been performed using the 2D TCAD device simulator, SILVACO, to obtain design parameters. The effect of various design parameters like pixel size, pixel depth, implant width, metal overhang, p-stop concentration, p-stop depth and bulk doping density on the leakage current and critical electric field are studied for both non-irradiated as well as irradiated pixel sensors. These 2D simulation results of planar pixels are useful for providing insight into the behaviour of non-irradiated and irradiated silicon pixel sensors and further work on 3D simulation is underway.

  12. Design optimization of pixel sensors using device simulations for the phase-II CMS tracker upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Jain, G., E-mail: geetikajain.hep@gmail.com [CDRST, Department of Physics & Astrophysics, University of Delhi, Delhi (India); Bhardwaj, A.; Dalal, R. [CDRST, Department of Physics & Astrophysics, University of Delhi, Delhi (India); Eber, R. [Institute fur Experimentelle Kernphysik (Germany); Eichorn, T. [Deutsches Elektronen Synchrotron (Germany); Fernandez, M. [Instituto de Fisica de Cantabria (Spain); Lalwani, K. [CDRST, Department of Physics & Astrophysics, University of Delhi, Delhi (India); Messineo, A. [Universita di Pisa & INFN sez. di Pisa (Italy); Palomo, F.R. [Escuela Superior de Ingenieros, Universidad de Sevilla (Spain); Peltola, T. [Helsinki Institute of Physics (Finland); Printz, M. [Institute fur Experimentelle Kernphysik (Germany); Ranjan, K. [CDRST, Department of Physics & Astrophysics, University of Delhi, Delhi (India); Villa, I. [Instituto de Fisica de Cantabria (Spain); Hidalgo, S. [Instituto de Microelectronica de Barcelona, Centro Nacional de Microelectronica (Spain)

    2016-07-11

    In order to address the problems caused by the harsh radiation environment during the high luminosity phase of the LHC (HL-LHC), all silicon tracking detectors (pixels and strips) in the CMS experiment will undergo an upgrade. And so to develop radiation hard pixel sensors, simulations have been performed using the 2D TCAD device simulator, SILVACO, to obtain design parameters. The effect of various design parameters like pixel size, pixel depth, implant width, metal overhang, p-stop concentration, p-stop depth and bulk doping density on the leakage current and critical electric field are studied for both non-irradiated as well as irradiated pixel sensors. These 2D simulation results of planar pixels are useful for providing insight into the behaviour of non-irradiated and irradiated silicon pixel sensors and further work on 3D simulation is underway.

  13. Simulation and experimental studies of a double-fiber angular displacement sensor

    Science.gov (United States)

    Zhu, Ruixue; Jing, Ruiping; Cheng, Yongjin

    2017-03-01

    A novel optical fiber angular displacement sensor is reported in this study. It gets the rotating angle of an object by means of the intensity modulation of a reflected light. The sensor probe, which is composed of an emitting fiber and a receiving fiber that are aligned along the vertical direction closely, is fixed directly on the rotating object. The measurements for axial displacement and angular displacement were operated separately. In particular, measurements for angular displacement were performed when the reflector is placed at different distances from the sensor probe separately. There is an excellent linearity between the angular displacement and the sensor output power. The results indicate that the larger the distance between the sensor probe and the reflector, the higher sensitivity the angular displacement sensor has. A theoretical model of the sensor is also developed and the simulate computation demonstrates that the theoretical results are in accordance with the experimental ones. The linear sensing range is ±7.2°, and the maximum sensitivity is 13.71%/deg. Furthermore, the hysteresis and the reproducibility of the measurement of the sensor are investigated. The designed sensor provides a kind of simple and effective method for measuring the angular displacement of a shaft system in practice due to its small size, light weight, good linearity and reproducibility.

  14. A High-Level MultiFunction Radar Simulation for Studying the Performance of MultiSensor Data Fusion Systems

    NARCIS (Netherlands)

    Huizing, A.G.; Bossee, E.

    1998-01-01

    This paper presents the basic requirements for a simulation of the main capabilities of a shipborne MultiFunction Radar (MFR) that can be used in conjunction with other sensor simulations in scenarios for studying Multi Sensor Data Fusion (MSDF) systems. This simulation is being used to support an

  15. ATTIRE (analytical tools for thermal infrared engineering): A sensor simulation and modeling package

    Science.gov (United States)

    Jaggi, S.

    1993-01-01

    The Advanced Sensor Development Laboratory (ASDL) at the Stennis Space Center develops, maintains and calibrates remote sensing instruments for the National Aeronautics & Space Administration (NASA). To perform system design trade-offs, analysis, and establish system parameters, ASDL has developed a software package for analytical simulation of sensor systems. This package called 'Analytical Tools for Thermal InfraRed Engineering' - ATTIRE, simulates the various components of a sensor system. The software allows each subsystem of the sensor to be analyzed independently for its performance. These performance parameters are then integrated to obtain system level information such as Signal-to-Noise Ratio (SNR), Noise Equivalent Radiance (NER), Noise Equivalent Temperature Difference (NETD) etc. This paper describes the uses of the package and the physics that were used to derive the performance parameters.

  16. Acoustic Environment Simulation Study; Acoustic Intrusion Sensor Performance.

    Science.gov (United States)

    1983-01-01

    generation of transients. 10,000. 13. Software for stastistical record keeping. 7,500. Note that no allowance is made here for additional racks or backplanes...sAcoustic Instrusion Sensor Performance Date Jan 83 I 0.1. TERMINOLOGY ATSA APPLIED TIME SERIES ANALYSIS, R. K. Otnes and L. Enochson, Wiley Interscience...verif- ication of the procedures. The terminology used in this report is essentially the same as that in APPLIED TIME SERIES ANALYSIS, VOLUME I, by Robert

  17. Unmanned aerial vehicle (UAV)-based monitoring of a landslide: Gallenzerkogel landslide (Ybbs-Lower Austria) case study.

    Science.gov (United States)

    Eker, Remzi; Aydın, Abdurrahim; Hübl, Johannes

    2017-12-19

    In the present study, UAV-based monitoring of the Gallenzerkogel landslide (Ybbs, Lower Austria) was carried out by three flight missions. High-resolution digital elevation models (DEMs), orthophotos, and density point clouds were generated from UAV-based aerial photos via structure-from-motion (SfM). According to ground control points (GCPs), an average of 4 cm root mean square error (RMSE) was found for all models. In addition, light detection and ranging (LIDAR) data from 2009, representing the prefailure topography, was utilized as a digital terrain model (DTM) and digital surface model (DSM). First, the DEM of difference (DoD) between the first UAV flight data and the LIDAR-DTM was determined and according to the generated DoD deformation map, an elevation difference of between - 6.6 and 2 m was found. Over the landslide area, a total of 4380.1 m 3 of slope material had been eroded, while 297.4 m 3 of the material had accumulated within the most active part of the slope. In addition, 688.3 m 3 of the total eroded material had belonged to the road destroyed by the landslide. Because of the vegetation surrounding the landslide area, the Multiscale Model-to-Model Cloud Comparison (M3C2) algorithm was then applied to compare the first and second UAV flight data. After eliminating both the distance uncertainty values of higher than 15 cm and the nonsignificant changes, the M3C2 distance obtained was between - 2.5 and 2.5 m. Moreover, the high-resolution orthophoto generated by the third flight allowed visual monitoring of the ongoing control/stabilization work in the area.

  18. Multi-sensor Cloud Retrieval Simulator and Remote Sensing from Model Parameters . Pt. 1; Synthetic Sensor Radiance Formulation; [Synthetic Sensor Radiance Formulation

    Science.gov (United States)

    Wind, G.; DaSilva, A. M.; Norris, P. M.; Platnick, S.

    2013-01-01

    In this paper we describe a general procedure for calculating synthetic sensor radiances from variable output from a global atmospheric forecast model. In order to take proper account of the discrepancies between model resolution and sensor footprint, the algorithm takes explicit account of the model subgrid variability, in particular its description of the probability density function of total water (vapor and cloud condensate.) The simulated sensor radiances are then substituted into an operational remote sensing algorithm processing chain to produce a variety of remote sensing products that would normally be produced from actual sensor output. This output can then be used for a wide variety of purposes such as model parameter verification, remote sensing algorithm validation, testing of new retrieval methods and future sensor studies.We show a specific implementation using the GEOS-5 model, the MODIS instrument and the MODIS Adaptive Processing System (MODAPS) Data Collection 5.1 operational remote sensing cloud algorithm processing chain (including the cloud mask, cloud top properties and cloud optical and microphysical properties products). We focus on clouds because they are very important to model development and improvement.

  19. Numerical simulation and design of a fluxset sensor by finite element method

    Energy Technology Data Exchange (ETDEWEB)

    Preis, K.; Bardi, I.; Biro, O.; Richter, K.R. [Technical Univ. of Graz (Austria); Pavo, J. [Technical Univ. of Budapest (Hungary); Gasparics, A. [Research Inst. for Material Science, Budapest (Hungary); Ticar, I. [Univ. of Maribor (Slovenia)

    1998-09-01

    A 3D model of a fluxset sensor serving to measure magnetic fields arising in Eddy Current Nondestructive Testing applications is analyzed by the finite element method. The voltage induced in the pick-up coil is obtained by computing the flux of the core of the sensor for several values of the exciting current at various external fields. It is shown that the time shift of the ensuing voltage impulse depends linearly on the external field in a wide range. The behavior of the sensor is furthermore simulated in a real nondestructive testing arrangement consisting of an exciting coil located above a conducting plate with a crack.

  20. Combined Simulation of a Micro Permanent Magnetic Linear Contactless Displacement Sensor

    Directory of Open Access Journals (Sweden)

    Jing Gao

    2010-09-01

    Full Text Available The permanent magnetic linear contactless displacement (PLCD sensor is a new type of displacement sensor operating on the magnetic inductive principle. It has many excellent properties and has already been used for many applications. In this article a Micro-PLCD sensor which can be used for microelectromechanical system (MEMS measurements is designed and simulated with the CST EM STUDIO® software, including building a virtual model, magnetostatic calculations, low frequency calculations, steady current calculations and thermal calculations. The influence of some important parameters such as air gap dimension, working frequency, coil current and eddy currents etc. is studied in depth.

  1. Combined simulation of a micro permanent magnetic linear contactless displacement sensor.

    Science.gov (United States)

    Gao, Jing; Müller, Wolfgang F O; Greiner, Felix; Eicher, Dirk; Weiland, Thomas; Schlaak, Helmut F

    2010-01-01

    The permanent magnetic linear contactless displacement (PLCD) sensor is a new type of displacement sensor operating on the magnetic inductive principle. It has many excellent properties and has already been used for many applications. In this article a Micro-PLCD sensor which can be used for microelectromechanical system (MEMS) measurements is designed and simulated with the CST EM STUDIO(®) software, including building a virtual model, magnetostatic calculations, low frequency calculations, steady current calculations and thermal calculations. The influence of some important parameters such as air gap dimension, working frequency, coil current and eddy currents etc. is studied in depth.

  2. Passive wireless antenna sensor for strain and crack sensing—electromagnetic modeling, simulation, and testing

    International Nuclear Information System (INIS)

    Yi, Xiaohua; Cho, Chunhee; Wang, Yang; Cooper, James; Tentzeris, Manos M; Leon, Roberto T

    2013-01-01

    This research investigates a passive wireless antenna sensor designed for strain and crack sensing. When the antenna experiences deformation, the antenna shape changes, causing a shift in the electromagnetic resonance frequency of the antenna. A radio frequency identification (RFID) chip is adopted for antenna signal modulation, so that a wireless reader can easily distinguish the backscattered sensor signal from unwanted environmental reflections. The RFID chip captures its operating power from an interrogation electromagnetic wave emitted by the reader, which allows the antenna sensor to be passive (battery-free). This paper first reports the latest simulation results on radiation patterns, surface current density, and electromagnetic field distribution. The simulation results are followed with experimental results on the strain and crack sensing performance of the antenna sensor. Tensile tests show that the wireless antenna sensor can detect small strain changes lower than 20 με, and can perform well at large strains higher than 10 000 με. With a high-gain reader antenna, the wireless interrogation distance can be increased up to 2.1 m. Furthermore, an array of antenna sensors is capable of measuring the strain distribution in close proximity. During emulated crack and fatigue crack tests, the antenna sensor is able to detect the growth of a small crack. (paper)

  3. a Mobile Multi-Sensor Platform for Building Reconstruction Integrating Terrestrial and Autonomous Uav-Based Close Range Data Acquisition

    Science.gov (United States)

    Cefalu, A.; Haala, N.; Schmohl, S.; Neumann, I.; Genz, T.

    2017-08-01

    Photogrammetric data capture of complex 3D objects using UAV imagery has become commonplace. Software tools based on algorithms like Structure-from-Motion and multi-view stereo image matching enable the fully automatic generation of densely meshed 3D point clouds. In contrast, the planning of a suitable image network usually requires considerable effort of a human expert, since this step directly influences the precision and completeness of the resulting point cloud. Planning of suitable camera stations can be rather complex, in particular for objects like buildings, bridges and monuments, which frequently feature strong depth variations to be acquired by high resolution images at a short distance. Within the paper, we present an automatic flight mission planning tool, which generates flight lines while aiming at camera configurations, which maintain a roughly constant object distance, provide sufficient image overlap and avoid unnecessary stations. Planning is based on a coarse Digital Surface Model and an approximate building outline. As a proof of concept, we use the tool within our research project MoVEQuaD, which aims at the reconstruction of building geometry at sub-centimetre accuracy.

  4. Review of Automatic Feature Extraction from High-Resolution Optical Sensor Data for UAV-Based Cadastral Mapping

    OpenAIRE

    Sophie Crommelinck; Rohan Bennett; Markus Gerke; Francesco Nex; Michael Ying Yang; George Vosselman

    2016-01-01

    Unmanned Aerial Vehicles (UAVs) have emerged as a rapid, low-cost and flexible acquisition system that appears feasible for application in cadastral mapping: high-resolution imagery, acquired using UAVs, enables a new approach for defining property boundaries. However, UAV-derived data are arguably not exploited to its full potential: based on UAV data, cadastral boundaries are visually detected and manually digitized. A workflow that automatically extracts boundary features from UAV data cou...

  5. Thermal Mapping Airborne Simulator for Small Satellite Sensor, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — A high performance, inexpensive, airborne simulator that will serve as the prototype for a small satellite based imaging system capable of mapping thermal anomalies...

  6. Analysis of simulated image sequences from sensors for restricted-visibility operations

    Science.gov (United States)

    Kasturi, Rangachar

    1991-01-01

    A real time model of the visible output from a 94 GHz sensor, based on a radiometric simulation of the sensor, was developed. A sequence of images as seen from an aircraft as it approaches for landing was simulated using this model. Thirty frames from this sequence of 200 x 200 pixel images were analyzed to identify and track objects in the image using the Cantata image processing package within the visual programming environment provided by the Khoros software system. The image analysis operations are described.

  7. Design and simulation of sensor networks for tracking Wifi users in outdoor urban environments

    Science.gov (United States)

    Thron, Christopher; Tran, Khoi; Smith, Douglas; Benincasa, Daniel

    2017-05-01

    We present a proof-of-concept investigation into the use of sensor networks for tracking of WiFi users in outdoor urban environments. Sensors are fixed, and are capable of measuring signal power from users' WiFi devices. We derive a maximum likelihood estimate for user location based on instantaneous sensor power measurements. The algorithm takes into account the effects of power control, and is self-calibrating in that the signal power model used by the location algorithm is adjusted and improved as part of the operation of the network. Simulation results to verify the system's performance are presented. The simulation scenario is based on a 1.5 km2 area of lower Manhattan, The self-calibration mechanism was verified for initial rms (root mean square) errors of up to 12 dB in the channel power estimates: rms errors were reduced by over 60% in 300 track-hours, in systems with limited power control. Under typical operating conditions with (without) power control, location rms errors are about 8.5 (5) meters with 90% accuracy within 9 (13) meters, for both pedestrian and vehicular users. The distance error distributions for smaller distances (<30 m) are well-approximated by an exponential distribution, while the distributions for large distance errors have fat tails. The issue of optimal sensor placement in the sensor network is also addressed. We specify a linear programming algorithm for determining sensor placement for networks with reduced number of sensors. In our test case, the algorithm produces a network with 18.5% fewer sensors with comparable accuracy estimation performance. Finally, we discuss future research directions for improving the accuracy and capabilities of sensor network systems in urban environments.

  8. Development and Validation of a UAV Based System for Air Pollution Measurements

    OpenAIRE

    Tommaso Francesco Villa; Farhad Salimi; Kye Morton; Lidia Morawska; Felipe Gonzalez

    2016-01-01

    Air quality data collection near pollution sources is difficult, particularly when sites are complex, have physical barriers, or are themselves moving. Small Unmanned Aerial Vehicles (UAVs) offer new approaches to air pollution and atmospheric studies. However, there are a number of critical design decisions which need to be made to enable representative data collection, in particular the location of the air sampler or air sensor intake. The aim of this research was to establish the best moun...

  9. Mini-UAV based sensory system for measuring environmental variables in greenhouses.

    Science.gov (United States)

    Roldán, Juan Jesús; Joossen, Guillaume; Sanz, David; del Cerro, Jaime; Barrientos, Antonio

    2015-02-02

    This paper describes the design, construction and validation of a mobile sensory platform for greenhouse monitoring. The complete system consists of a sensory system on board a small quadrotor (i.e., a four rotor mini-UAV). The goals of this system include taking measures of temperature, humidity, luminosity and CO2 concentration and plotting maps of these variables. These features could potentially allow for climate control, crop monitoring or failure detection (e.g., a break in a plastic cover). The sensors have been selected by considering the climate and plant growth models and the requirements for their integration onboard the quadrotor. The sensors layout and placement have been determined through a study of quadrotor aerodynamics and the influence of the airflows from its rotors. All components of the system have been developed, integrated and tested through a set of field experiments in a real greenhouse. The primary contributions of this paper are the validation of the quadrotor as a platform for measuring environmental variables and the determination of the optimal location of sensors on a quadrotor.

  10. Mini-UAV Based Sensory System for Measuring Environmental Variables in Greenhouses

    Directory of Open Access Journals (Sweden)

    Juan Jesús Roldán

    2015-02-01

    Full Text Available This paper describes the design, construction and validation of a mobile sensory platform for greenhouse monitoring. The complete system consists of a sensory system on board a small quadrotor (i.e., a four rotor mini-UAV. The goals of this system include taking measures of temperature, humidity, luminosity and CO2 concentration and plotting maps of these variables. These features could potentially allow for climate control, crop monitoring or failure detection (e.g., a break in a plastic cover. The sensors have been selected by considering the climate and plant growth models and the requirements for their integration onboard the quadrotor. The sensors layout and placement have been determined through a study of quadrotor aerodynamics and the influence of the airflows from its rotors. All components of the system have been developed, integrated and tested through a set of field experiments in a real greenhouse. The primary contributions of this paper are the validation of the quadrotor as a platform for measuring environmental variables and the determination of the optimal location of sensors on a quadrotor.

  11. Optimum wireless sensor deployment scheme for structural health monitoring: a simulation study

    Science.gov (United States)

    Liu, Chengyin; Fang, Kun; Teng, Jun

    2015-11-01

    With the rapid advancements in smart sensing technology and wireless communication technology, the wireless sensor network (WSN) offers an alternative solution to structural health monitoring (SHM). In WSNs, dense deployment of wireless nodes aids the identification of structural dynamic characteristics, while data transmission is a significant issue since wireless channels typically have a lower bandwidth and a limited power supply. This paper provides a wireless sensor deployment optimization scheme for SHM, in terms of both energy consumption and modal identification accuracy. A spherical energy model is established to formulate the energy consumption within a WSN. The optimal number of sensors and their locations are obtained through solving a multi-objective function with weighting factors on energy consumption and modal identification accuracy using a genetic algorithm (GA). Simulation and comparison results with traditional sensor deployment methods demonstrate the efficiency of the proposed optimization scheme.

  12. Predictive simulations and optimization of nanowire field-effect PSA sensors including screening

    KAUST Repository

    Baumgartner, Stefan

    2013-05-03

    We apply our self-consistent PDE model for the electrical response of field-effect sensors to the 3D simulation of nanowire PSA (prostate-specific antigen) sensors. The charge concentration in the biofunctionalized boundary layer at the semiconductor-electrolyte interface is calculated using the propka algorithm, and the screening of the biomolecules by the free ions in the liquid is modeled by a sensitivity factor. This comprehensive approach yields excellent agreement with experimental current-voltage characteristics without any fitting parameters. Having verified the numerical model in this manner, we study the sensitivity of nanowire PSA sensors by changing device parameters, making it possible to optimize the devices and revealing the attributes of the optimal field-effect sensor. © 2013 IOP Publishing Ltd.

  13. Experimental Evaluation of Simulation Abstractions for Wireless Sensor Network MAC Protocols

    Directory of Open Access Journals (Sweden)

    G. P. Halkes

    2010-01-01

    Full Text Available The evaluation of MAC protocols for Wireless Sensor Networks (WSNs is often performed through simulation. These simulations necessarily abstract away from reality in many ways. However, the impact of these abstractions on the results of the simulations has received only limited attention. Moreover, many studies on the accuracy of simulation have studied either the physical layer and per link effects or routing protocol effects. To the best of our knowledge, no other work has focused on the study of the simulation abstractions with respect to MAC protocol performance. In this paper, we present the results of an experimental study of two often used abstractions in the simulation of WSN MAC protocols. We show that a simple SNR-based reception model can provide quite accurate results for metrics commonly used to evaluate MAC protocols. Furthermore, we provide an analysis of what the main sources of deviation are and thereby how the simulations can be improved to provide even better results.

  14. Calculation for simulation of archery goal value using a web camera and ultrasonic sensor

    Science.gov (United States)

    Rusjdi, Darma; Abdurrasyid, Wulandari, Dewi Arianti

    2017-08-01

    Development of the device simulator digital indoor archery-based embedded systems as a solution to the limitations of the field or open space is adequate, especially in big cities. Development of the device requires simulations to calculate the value of achieving the target based on the approach defined by the parabolic motion variable initial velocity and direction of motion of the arrow reaches the target. The simulator device should be complemented with an initial velocity measuring device using ultrasonic sensors and measuring direction of the target using a digital camera. The methodology uses research and development of application software from modeling and simulation approach. The research objective to create simulation applications calculating the value of the achievement of the target arrows. Benefits as a preliminary stage for the development of the simulator device of archery. Implementation of calculating the value of the target arrows into the application program generates a simulation game of archery that can be used as a reference development of the digital archery simulator in a room with embedded systems using ultrasonic sensors and web cameras. Applications developed with the simulation calculation comparing the outer radius of the circle produced a camera from a distance of three meters.

  15. Fast-performance simulation for Gossip-based Wireless Sensor Networks

    NARCIS (Netherlands)

    Blagojević, M.; Geilen, M.; Basten, A.A.; Nabi, M.; Hendriks, T.

    2014-01-01

    Gossip-based Wireless Sensor Networks (GWSNs) are complex systems of inherently random nature. Planning and designing GWSNs requires a fast and adequately accurate mechanism to estimate system performance. As a first contribution, we propose a performance analysis technique that simulates the

  16. Simulation of at-sensor radiance over land for proposed thermal ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 120; Issue 1. Simulation of at-sensor radiance over land for proposed thermal channels of Imager payload onboard INSAT-3D satellite using MODTRAN model. M R Pandya D B Shah H J Trivedi S Panigrahy. Volume 120 Issue 1 February 2011 pp 19-25 ...

  17. Accurate Behavioral Simulator of All-Digital Time-Domain Smart Temperature Sensors by Using SIMULINK

    Directory of Open Access Journals (Sweden)

    Chun-Chi Chen

    2016-08-01

    Full Text Available This study proposes a new behavioral simulator that uses SIMULINK for all-digital CMOS time-domain smart temperature sensors (TDSTSs for performing rapid and accurate simulations. Inverter-based TDSTSs offer the benefits of low cost and simple structure for temperature-to-digital conversion and have been developed. Typically, electronic design automation tools, such as HSPICE, are used to simulate TDSTSs for performance evaluations. However, such tools require extremely long simulation time and complex procedures to analyze the results and generate figures. In this paper, we organize simple but accurate equations into a temperature-dependent model (TDM by which the TDSTSs evaluate temperature behavior. Furthermore, temperature-sensing models of a single CMOS NOT gate were devised using HSPICE simulations. Using the TDM and these temperature-sensing models, a novel simulator in SIMULINK environment was developed to substantially accelerate the simulation and simplify the evaluation procedures. Experiments demonstrated that the simulation results of the proposed simulator have favorable agreement with those obtained from HSPICE simulations, showing that the proposed simulator functions successfully. This is the first behavioral simulator addressing the rapid simulation of TDSTSs.

  18. Accurate Behavioral Simulator of All-Digital Time-Domain Smart Temperature Sensors by Using SIMULINK.

    Science.gov (United States)

    Chen, Chun-Chi; Chen, Chao-Lieh; Lin, You-Ting

    2016-08-08

    This study proposes a new behavioral simulator that uses SIMULINK for all-digital CMOS time-domain smart temperature sensors (TDSTSs) for performing rapid and accurate simulations. Inverter-based TDSTSs offer the benefits of low cost and simple structure for temperature-to-digital conversion and have been developed. Typically, electronic design automation tools, such as HSPICE, are used to simulate TDSTSs for performance evaluations. However, such tools require extremely long simulation time and complex procedures to analyze the results and generate figures. In this paper, we organize simple but accurate equations into a temperature-dependent model (TDM) by which the TDSTSs evaluate temperature behavior. Furthermore, temperature-sensing models of a single CMOS NOT gate were devised using HSPICE simulations. Using the TDM and these temperature-sensing models, a novel simulator in SIMULINK environment was developed to substantially accelerate the simulation and simplify the evaluation procedures. Experiments demonstrated that the simulation results of the proposed simulator have favorable agreement with those obtained from HSPICE simulations, showing that the proposed simulator functions successfully. This is the first behavioral simulator addressing the rapid simulation of TDSTSs.

  19. UAV-Based Thermal Imaging for High-Throughput Field Phenotyping of Black Poplar Response to Drought

    Directory of Open Access Journals (Sweden)

    Riccardo Ludovisi

    2017-09-01

    Full Text Available Poplars are fast-growing, high-yielding forest tree species, whose cultivation as second-generation biofuel crops is of increasing interest and can efficiently meet emission reduction goals. Yet, breeding elite poplar trees for drought resistance remains a major challenge. Worldwide breeding programs are largely focused on intra/interspecific hybridization, whereby Populus nigra L. is a fundamental parental pool. While high-throughput genotyping has resulted in unprecedented capabilities to rapidly decode complex genetic architecture of plant stress resistance, linking genomics to phenomics is hindered by technically challenging phenotyping. Relying on unmanned aerial vehicle (UAV-based remote sensing and imaging techniques, high-throughput field phenotyping (HTFP aims at enabling highly precise and efficient, non-destructive screening of genotype performance in large populations. To efficiently support forest-tree breeding programs, ground-truthing observations should be complemented with standardized HTFP. In this study, we develop a high-resolution (leaf level HTFP approach to investigate the response to drought of a full-sib F2 partially inbred population (termed here ‘POP6’, whose F1 was obtained from an intraspecific P. nigra controlled cross between genotypes with highly divergent phenotypes. We assessed the effects of two water treatments (well-watered and moderate drought on a population of 4603 trees (503 genotypes hosted in two adjacent experimental plots (1.67 ha by conducting low-elevation (25 m flights with an aerial drone and capturing 7836 thermal infrared (TIR images. TIR images were undistorted, georeferenced, and orthorectified to obtain radiometric mosaics. Canopy temperature (Tc was extracted using two independent semi-automated segmentation techniques, eCognition- and Matlab-based, to avoid the mixed-pixel problem. Overall, results showed that the UAV platform-based thermal imaging enables to effectively assess genotype

  20. UAV-Based Thermal Imaging for High-Throughput Field Phenotyping of Black Poplar Response to Drought.

    Science.gov (United States)

    Ludovisi, Riccardo; Tauro, Flavia; Salvati, Riccardo; Khoury, Sacha; Mugnozza Scarascia, Giuseppe; Harfouche, Antoine

    2017-01-01

    Poplars are fast-growing, high-yielding forest tree species, whose cultivation as second-generation biofuel crops is of increasing interest and can efficiently meet emission reduction goals. Yet, breeding elite poplar trees for drought resistance remains a major challenge. Worldwide breeding programs are largely focused on intra/interspecific hybridization, whereby Populus nigra L. is a fundamental parental pool. While high-throughput genotyping has resulted in unprecedented capabilities to rapidly decode complex genetic architecture of plant stress resistance, linking genomics to phenomics is hindered by technically challenging phenotyping. Relying on unmanned aerial vehicle (UAV)-based remote sensing and imaging techniques, high-throughput field phenotyping (HTFP) aims at enabling highly precise and efficient, non-destructive screening of genotype performance in large populations. To efficiently support forest-tree breeding programs, ground-truthing observations should be complemented with standardized HTFP. In this study, we develop a high-resolution (leaf level) HTFP approach to investigate the response to drought of a full-sib F 2 partially inbred population (termed here 'POP6'), whose F 1 was obtained from an intraspecific P. nigra controlled cross between genotypes with highly divergent phenotypes. We assessed the effects of two water treatments (well-watered and moderate drought) on a population of 4603 trees (503 genotypes) hosted in two adjacent experimental plots (1.67 ha) by conducting low-elevation (25 m) flights with an aerial drone and capturing 7836 thermal infrared (TIR) images. TIR images were undistorted, georeferenced, and orthorectified to obtain radiometric mosaics. Canopy temperature ( T c ) was extracted using two independent semi-automated segmentation techniques, eCognition- and Matlab-based, to avoid the mixed-pixel problem. Overall, results showed that the UAV platform-based thermal imaging enables to effectively assess genotype

  1. Sensors

    CERN Document Server

    Pigorsch, Enrico

    1997-01-01

    This is the 5th edition of the Metra Martech Directory "EUROPEAN CENTRES OF EXPERTISE - SENSORS." The entries represent a survey of European sensors development. The new edition contains 425 detailed profiles of companies and research institutions in 22 countries. This is reflected in the diversity of sensors development programmes described, from sensors for physical parameters to biosensors and intelligent sensor systems. We do not claim that all European organisations developing sensors are included, but this is a good cross section from an invited list of participants. If you see gaps or omissions, or would like your organisation to be included, please send details. The data base invites the formation of effective joint ventures by identifying and providing access to specific areas in which organisations offer collaboration. This issue is recognised to be of great importance and most entrants include details of collaboration offered and sought. We hope the directory on Sensors will help you to find the ri...

  2. Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, H. [PBI-Dansensor A/S (Denmark); Toft Soerensen, O. [Risoe National Lab., Materials Research Dept. (Denmark)

    1999-10-01

    A new type of ceramic oxygen sensors based on semiconducting oxides was developed in this project. The advantage of these sensors compared to standard ZrO{sub 2} sensors is that they do not require a reference gas and that they can be produced in small sizes. The sensor design and the techniques developed for production of these sensors are judged suitable by the participating industry for a niche production of a new generation of oxygen sensors. Materials research on new oxygen ion conducting conductors both for applications in oxygen sensors and in fuel was also performed in this project and finally a new process was developed for fabrication of ceramic tubes by dip-coating. (EHS)

  3. Numerical simulation of a DFB - fiber laser sensor (part 1

    Directory of Open Access Journals (Sweden)

    Dan SAVASTRU

    2010-06-01

    Full Text Available This paper presents the preliminary results obtained in developing a numerical simulationanalysis of fiber optic bending sensitivity aiming to improve the design of fiber lasers. The developednumerical simulation method relies on an analysis of both the fundamental mode propagation alongan optical fiber and of how bending of this fiber influence the optical radiation losses. The cases ofsimple, undoped and of doped with Er3+ ions optical fibers are considered. The presented results arebased on numerical simulation of eigen-modes of a laser intensity distribution by the use of finiteelement method (FEM developed in the frame of COMSOL software package. The numericalsimulations are performed by considering the cases of both normal, non-deformed optic fiber and ofsymmetrically deformed optic fiber resembling micro-bending of it. Both types of fiber optic bendinglosses are analyzed, namely: the transition loss, associated with the abrupt or rapid change incurvature at the beginning and the end of a bend, and pure bend loss is associated with the loss fromthe bend of constant curvature in between.

  4. Sensors as confidence building measures: A demonstration using a combat simulation

    Energy Technology Data Exchange (ETDEWEB)

    Warshawsky, A.S.; Spinosa, A.; Pimper, J.

    1994-06-01

    Numerous combat simulations have been developed and used to study the consequences of alternative force structures, analyze weapon performance, and train combat force commanders. These same simulations can, with minor modifications, be used to study a suite of arms control issues. To demonstrate this point, a modification of the LLNL Joint Conflict Model (JCM) was used to explain the utility of unattended ground sensors (UGS) as confidence building measures (CBMs) in the context of a regional arms control situation. It was shown that existing simulations (in particular, JCM) have the functionality necessary to easily and readily address regional arms control issues in a meaningful fashion.

  5. 3D Path Planning of UAV Based on Improved A * Algorithm

    Directory of Open Access Journals (Sweden)

    Tian Zhe-Tong

    2017-01-01

    Full Text Available A 3D path planning method based on A* algorithm is proposed. This method introduces the constraints of UAV and line-of-sight communication with ground stations, and it combines the UAV’s maneuverability, mission requirements and terrain information and other constraints together to avoid terrain and threat. The method of extending the child nodes to the 3D detailed position calculation is also provided. The simulation is realized by Unity 3D software, and the simulation results show that the proposed method can be used to plan the 3D path of UAV which meets UAV constraints.

  6. Design, Simulation and Analysis of Cantilever Sensor for in-Vitro LDL Detection

    Directory of Open Access Journals (Sweden)

    Dr. S. Hosimin Thilagar

    2011-07-01

    Full Text Available This work is focused on the design, simulation and analysis of microcantilever integrated with piezoresistors in Wheatstone bridge arrangement to detect low density lipoprotein (LDL in blood, which is responsible for cholesterol accumulation in arteries. This paper uses Finite Element Method (FEM to obtain the performance of piezoresistive microcantilever sensor to measure surface stress corresponding to the adsorption of LDL molecules. The FEM results are compared with the analytical solutions. The results suggest that the designed sensor can effectively sense LDL molecules as in-Vitro with few micro-litre of blood sample.

  7. UAV-based detection and spatial analyses of periglacial landforms on Demay Point (King George Island, South Shetland Islands, Antarctica)

    Science.gov (United States)

    Dąbski, Maciej; Zmarz, Anna; Pabjanek, Piotr; Korczak-Abshire, Małgorzata; Karsznia, Izabela; Chwedorzewska, Katarzyna J.

    2017-08-01

    High-resolution aerial images allow detailed analyses of periglacial landforms, which is of particular importance in light of climate change and resulting changes in active layer thickness. The aim of this study is to show possibilities of using UAV-based photography to perform spatial analysis of periglacial landforms on the Demay Point peninsula, King George Island, and hence to supplement previous geomorphological studies of the South Shetland Islands. Photogrammetric flights were performed using a PW-ZOOM fixed-winged unmanned aircraft vehicle. Digital elevation models (DEM) and maps of slope and contour lines were prepared in ESRI ArcGIS 10.3 with the Spatial Analyst extension, and three-dimensional visualizations in ESRI ArcScene 10.3 software. Careful interpretation of orthophoto and DEM, allowed us to vectorize polygons of landforms, such as (i) solifluction landforms (solifluction sheets, tongues, and lobes); (ii) scarps, taluses, and a protalus rampart; (iii) patterned ground (hummocks, sorted circles, stripes, nets and labyrinths, and nonsorted nets and stripes); (iv) coastal landforms (cliffs and beaches); (v) landslides and mud flows; and (vi) stone fields and bedrock outcrops. We conclude that geomorphological studies based on commonly accessible aerial and satellite images can underestimate the spatial extent of periglacial landforms and result in incomplete inventories. The PW-ZOOM UAV is well suited to gather detailed geomorphological data and can be used in spatial analysis of periglacial landforms in the Western Antarctic Peninsula region.

  8. Temperature Simulation of Greenhouse with CFD Methods and Optimal Sensor Placement

    Directory of Open Access Journals (Sweden)

    Yanzheng Liu

    2014-03-01

    Full Text Available The accuracy of information monitoring is significant to increase the effect of Greenhouse Environment Control. In this paper, by taking simulation for the temperature field in the greenhouse as an example, the CFD (Computational Fluid Dynamics simulation model for measuring the microclimate environment of greenhouse with the principle of thermal environment formation was established, and the temperature distributions under the condition of mechanical ventilation was also simulated. The results showed that the CFD model and its solution simulated for greenhouse thermal environment could describe the changing process of temperature environment within the greenhouse; the most suitable turbulent simulation model was the standard k?? model. Under the condition of mechanical ventilation, the average deviation between the simulated value and the measured value was 0.6, which was 4.5 percent of the measured value. The distribution of temperature filed had obvious layering structures, and the temperature in the greenhouse model decreased gradually from the periphery to the center. Based on these results, the sensor number and the optimal sensor placement were determined with CFD simulation method.

  9. Integration of Thermoelectric Generator and Wireless Sensor Node Simulators

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Vivek [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Yanliang [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    This report focuses on integrating TEG and WSN simulators with DC-DC converter as an interface. Here DC stands for direct current. DC-DC converter is essential to balance a wide range of analog, digital, and radio loads acting on the energy source. Also, the voltage level generated by TEGs under varying temperature conditions could be low, irregular, and insufficient to operate WSN, therefore DC-DC is required to boost up the voltage to a desired level. Most of the main problems of DC-DC converters used in TEG system are related to impedance matching between the internal resistance of TEG and the input resistance of DC-DC converter. This report would address the issue associated with dynamic impedance matching under varying temperature conditions in the effort to integrate TEG and WSN. In this effort, dynamic impedance matching algorithms like perturb and observe (P&O) and extremum seeking control (ESC) algorithms will de implemented and compared to achieve maximum peak power tracking (MPPT). In addition, the report will summarize the experimental study performed at BSU on profiling behavior of WSN prototype.

  10. Simulation and analysis of sensitivity for tapered fiber Bragg grating evanescent wave sensor

    Science.gov (United States)

    Xu, Hong-zhi; Lou, Jun; Tan, Yao-cheng; Li, Ben-chong; Huang, Jie; Shen, Wei-min

    2014-12-01

    We have carried out a detailed simulative study of the tapered fiber Bragg grating (TFBG) evanescent wave sensor sensitivity by using 3-D Coupled-Mode Theory method. The method is based on the spectral interrogation mode of operation. We also make numerical simulations to figure out how the uniform waist diameter and the difference of the relative refractive indexes between fiber core and external medium affect the sensitivity of this proposed sensor. The simulation results show that the sensitivity of the tapered fiber Bragg grating will be improved when the diameter of the uniform waist decrease as well as the difference of the relative refractive indexes between fiber core and external medium. And with the fixed uniform waist diameter and tapered length, when the difference of the relative refractive index of fiber core and external medium varies is 0.015RIU, the values of wavelength shift is 5.08nm, the sensitivity of the tapered fiber Bragg grating is 317.5nm/RIU. The sensitivity is higher than that of the common FBG. The results are consistent with theoretical models. The simulation results can supply the guidance for the further experimental study and refractive index sensor design, optimization and application.

  11. Array of Love-wave sensors based on quartz/Novolac to detect CWA simulants.

    Science.gov (United States)

    Matatagui, D; Fontecha, J; Fernández, M J; Aleixandre, M; Gràcia, I; Cané, C; Horrillo, M C

    2011-09-15

    An array of Love-wave sensors based on quartz and Novolac has been developed to detect chemical warfare agents (CWAs). These weapons are a risk for human health due to their efficiency and high lethality; therefore an early and clear detection is of enormous importance for the people safety. Love-wave devices realized on quartz as piezoelectric substrate and Novolac as guiding layer have been used to make up an array of six sensors, which have been coated with specific polymers by spin coating. The CWAs are very dangerous and for safety reasons their well known simulants have been used: dimethylmethyl phosphonate (DMMP), dipropyleneglycol methyl ether (DPGME), dimethylmethyl acetamide (DMA), dichloroethane (DCE), dichloromethane (DCM) and dichloropentane (DCP). The array has been exposed to these CWA simulants detecting very low concentrations, such as 25 ppb of DMMP, a simulant of nerve agent sarin. Finally, principal component analysis (PCA) as data pre-processing and discrimination technique, and probabilistic neural networks (PNN) as patterns classification technique have been applied. The performance of the sensor array has shown stability, accuracy, high sensitivity and good selectivity to these simulants. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Simulations of 3D-Si sensors for the innermost layer of the ATLAS pixel upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Baselga, M.; Pellegrini, G., E-mail: giulio.pellegrini@imb-cnm.csic.es; Quirion, D.

    2017-03-01

    The LHC is expected to reach luminosities up to 3000 fb{sup −1} and the innermost layer of the ATLAS upgrade plans to cope with higher occupancy and to decrease the pixel size. 3D-Si sensors are a good candidate for the innermost layer of the ATLAS pixel upgrade since they exhibit good performance under high fluences and the new designs will have smaller pixel size to fulfill the electronics expectations. This paper reports TCAD simulations of the 3D-Si sensors designed at IMB-CNM with non-passing-through columns that are being fabricated for the next innermost layer of the ATLAS pixel upgrade. It shows the charge collection response before and after irradiation, and the response of 3D-Si sensors located at large η angles.

  13. UAV-Based L-Band SAR with Precision Flight Path Control

    Science.gov (United States)

    Madsen, Soren N.; Hensley, Scott; Wheeler, Kevin; Sadowy, Greg; Miller, Tim; Muellerschoen, Ron; Lou, Yunling; Rosen, Paul

    2004-01-01

    NASA's Jet Propulsion Laboratory is currently implementing a reconfigurable polarimetric L-band synthetic aperture radar (SAR), specifically designed to acquire airborne repeat track interferometric (RTI) SAR data, also know as differential interferometric measurements. Differential interferometry can provide key displacement measurements, important for the scientific studies of Earthquakes and volcanoes. Using precision real-time GPS and a sensor controlled flight management system, the system will be able to fly predefined paths with great precision. The radar will be designed to operate on a UAV (Unmanned Arial Vehicle) but will initially be demonstrated on a minimally piloted vehicle (MPV), such as the Proteus build by Scaled Composites. The application requires control of the flight path to within a 10 meter tube to support repeat track and formation flying measurements. The design is fully polarimetric with an 80 MHz bandwidth (2 meter range resolution) and 16 kilometer range swath. The antenna is an electronically steered array to assure that the actual antenna pointing can be controlled independent of the wind direction and speed. The system will nominally operate at 45,000 ft. The program started out as a Instrument Incubator Project (IIP) funded by NASA Earth Science and Technology Office (ESTO).

  14. UAV-based L-band SAR with precision flight path control

    Science.gov (United States)

    Madsen, Soren N.; Hensley, Scott; Wheeler, Kevin; Sadowy, Gregory A.; Miller, Tim; Muellerschoen, Ron; Lou, Yunling; Rosen, Paul A.

    2005-01-01

    NASA's Jet Propulsion Laboratory is currently implementing a reconfigurable polarimetric L-band synthetic aperture radar (SAR), specifically designed to acquire airborne repeat track interferometric (RTI) SAR data, also know as differential interferometric measurements. Differential interferometry can provide key displacement measurements, important for the scientific studies of Earthquakes and volcanoes1. Using precision real-time GPS and a sensor controlled flight management system, the system will be able to fly predefined paths with great precision. The radar will be designed to operate on a UAV (Unmanned Arial Vehicle) but will initially be demonstrated on a minimally piloted vehicle (MPV), such as the Proteus build by Scaled Composites. The application requires control of the flight path to within a 10 m tube to support repeat track and formation flying measurements. The design is fully polarimetric with an 80 MHz bandwidth (2 m range resolution) and 16 km range swath. The antenna is an electronically steered array to assure that the actual antenna pointing can be controlled independent of the wind direction and speed. The system will nominally operate at 45,000 ft. The program started out as a Instrument Incubator Project (IIP) funded by NASA Earth Science and Technology Office (ESTO).

  15. Virtual Deformation Control of the X-56A Model with Simulated Fiber Optic Sensors

    Science.gov (United States)

    Suh, Peter M.; Chin, Alexander W.; Mavris, Dimitri N.

    2014-01-01

    A robust control law design methodology is presented to stabilize the X-56A model and command its wing shape. The X-56A was purposely designed to experience flutter modes in its flight envelope. The methodology introduces three phases: the controller design phase, the modal filter design phase, and the reference signal design phase. A mu-optimal controller is designed and made robust to speed and parameter variations. A conversion technique is presented for generating sensor strain modes from sensor deformation mode shapes. The sensor modes are utilized for modal filtering and simulating fiber optic sensors for feedback to the controller. To generate appropriate virtual deformation reference signals, rigid-body corrections are introduced to the deformation mode shapes. After successful completion of the phases, virtual deformation control is demonstrated. The wing is deformed and it is shown that angle-ofattack changes occur which could potentially be used to an advantage. The X-56A program must demonstrate active flutter suppression. It is shown that the virtual deformation controller can achieve active flutter suppression on the X-56A simulation model.

  16. Sensor Fault Detection and Diagnosis Simulation of a Helicopter Engine in an Intelligent Control Framework

    Science.gov (United States)

    Litt, Jonathan; Kurtkaya, Mehmet; Duyar, Ahmet

    1994-01-01

    This paper presents an application of a fault detection and diagnosis scheme for the sensor faults of a helicopter engine. The scheme utilizes a model-based approach with real time identification and hypothesis testing which can provide early detection, isolation, and diagnosis of failures. It is an integral part of a proposed intelligent control system with health monitoring capabilities. The intelligent control system will allow for accommodation of faults, reduce maintenance cost, and increase system availability. The scheme compares the measured outputs of the engine with the expected outputs of an engine whose sensor suite is functioning normally. If the differences between the real and expected outputs exceed threshold values, a fault is detected. The isolation of sensor failures is accomplished through a fault parameter isolation technique where parameters which model the faulty process are calculated on-line with a real-time multivariable parameter estimation algorithm. The fault parameters and their patterns can then be analyzed for diagnostic and accommodation purposes. The scheme is applied to the detection and diagnosis of sensor faults of a T700 turboshaft engine. Sensor failures are induced in a T700 nonlinear performance simulation and data obtained are used with the scheme to detect, isolate, and estimate the magnitude of the faults.

  17. Design of Attitude Control System for UAV Based on Feedback Linearization and Adaptive Control

    Directory of Open Access Journals (Sweden)

    Wenya Zhou

    2014-01-01

    Full Text Available Attitude dynamic model of unmanned aerial vehicles (UAVs is multi-input multioutput (MIMO, strong coupling, and nonlinear. Model uncertainties and external gust disturbances should be considered during designing the attitude control system for UAVs. In this paper, feedback linearization and model reference adaptive control (MRAC are integrated to design the attitude control system for a fixed wing UAV. First of all, the complicated attitude dynamic model is decoupled into three single-input single-output (SISO channels by input-output feedback linearization. Secondly, the reference models are determined, respectively, according to the performance indexes of each channel. Subsequently, the adaptive control law is obtained using MRAC theory. In order to demonstrate the performance of attitude control system, the adaptive control law and the proportional-integral-derivative (PID control law are, respectively, used in the coupling nonlinear simulation model. Simulation results indicate that the system performance indexes including maximum overshoot, settling time (2% error range, and rise time obtained by MRAC are better than those by PID. Moreover, MRAC system has stronger robustness with respect to the model uncertainties and gust disturbance.

  18. SIMULATED 8 MeV NEUTRON RESPONSE FUNCTIONS OF A THIN SILICON NEUTRON SENSOR.

    Science.gov (United States)

    Takada, Masashi; Matsumoto, Tetsuro; Masuda, Akihiko; Nunomiya, Tomoya; Aoyama, Kei; Nakamura, Takashi

    2017-12-22

    Neutron response functions of a thin silicon neutron sensor are simulated using PHITS2 and MCNP6 codes for an 8 MeV neutron beam at angles of incidence of 0°, 30° and 60°. The contributions of alpha particles created from the 28Si(n,α)25Mg reaction and the silicon nuclei scattered elastically by neutrons in the silicon sensor have not been well reproduced using the MCNP6 code. The 8 MeV neutron response functions simulated using the PHITS2 code with an accurate event generator mode are in good agreement with experimental results and include the contributions of the alpha particles and silicon nuclei. © The Author(s) 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. PROCESSING OF UAV BASED RANGE IMAGING DATA TO GENERATE DETAILED ELEVATION MODELS OF COMPLEX NATURAL STRUCTURES

    Directory of Open Access Journals (Sweden)

    T. K. Kohoutek

    2012-07-01

    Full Text Available Unmanned Aerial Vehicles (UAVs are more and more used in civil areas like geomatics. Autonomous navigated platforms have a great flexibility in flying and manoeuvring in complex environments to collect remote sensing data. In contrast to standard technologies such as aerial manned platforms (airplanes and helicopters UAVs are able to fly closer to the object and in small-scale areas of high-risk situations such as landslides, volcano and earthquake areas and floodplains. Thus, UAVs are sometimes the only practical alternative in areas where access is difficult and where no manned aircraft is available or even no flight permission is given. Furthermore, compared to terrestrial platforms, UAVs are not limited to specific view directions and could overcome occlusions from trees, houses and terrain structures. Equipped with image sensors and/or laser scanners they are able to provide elevation models, rectified images, textured 3D-models and maps. In this paper we will describe a UAV platform, which can carry a range imaging (RIM camera including power supply and data storage for the detailed mapping and monitoring of complex structures, such as alpine riverbed areas. The UAV platform NEO from Swiss UAV was equipped with the RIM camera CamCube 2.0 by PMD Technologies GmbH to capture the surface structures. Its navigation system includes an autopilot. To validate the UAV-trajectory a 360° prism was installed and tracked by a total station. Within the paper a workflow for the processing of UAV-RIM data is proposed, which is based on the processing of differential GNSS data in combination with the acquired range images. Subsequently, the obtained results for the trajectory are compared and verified with a track of a UAV (Falcon 8, Ascending Technologies carried out with a total station simultaneously to the GNSS data acquisition. The results showed that the UAV's position using differential GNSS could be determined in the centimetre to the decimetre

  20. Control system design of flying-wing UAV based on nonlinear methodology

    Directory of Open Access Journals (Sweden)

    Ji-guang LI

    2017-12-01

    Full Text Available In this paper, A fluid vector rudder flying-wing UAV is employed as the design object, so as to study the nonlinear design method and flight validation. For the maneuvering flight control, this paper presents a control structure. This control structure included the inner loop linearization decoupling methods to eliminate the known negative coupling and the outer loop backstepping methods for trajectory tracking control. The stability of the control structure has been proved in this paper. Compared with the traditional backstepping control method, this controller increases the inner loop decoupling structure and retains the aerodynamic damping term which makes the linearized system a weak nonlinear system. This structure can not only reduce the conservatism of the outer loop controller design, but also is convenient for engineering implementation. Simulation and flight validation results show that the proposed control scheme is effective.

  1. Formation flight and collision avoidance for multiple UAVs based on modified tentacle algorithm in unstructured environments.

    Directory of Open Access Journals (Sweden)

    Minghuan Zhang

    Full Text Available This paper presents a method for formation flight and collision avoidance of multiple UAVs. Due to the shortcomings such as collision avoidance caused by UAV's high-speed and unstructured environments, this paper proposes a modified tentacle algorithm to ensure the high performance of collision avoidance. Different from the conventional tentacle algorithm which uses inverse derivation, the modified tentacle algorithm rapidly matches the radius of each tentacle and the steering command, ensuring that the data calculation problem in the conventional tentacle algorithm is solved. Meanwhile, both the speed sets and tentacles in one speed set are reduced and reconstructed so as to be applied to multiple UAVs. Instead of path iterative optimization, the paper selects the best tentacle to obtain the UAV collision avoidance path quickly. The simulation results show that the method presented in the paper effectively enhances the performance of flight formation and collision avoidance for multiple high-speed UAVs in unstructured environments.

  2. Formation flight and collision avoidance for multiple UAVs based on modified tentacle algorithm in unstructured environments.

    Science.gov (United States)

    Zhang, Minghuan

    2017-01-01

    This paper presents a method for formation flight and collision avoidance of multiple UAVs. Due to the shortcomings such as collision avoidance caused by UAV's high-speed and unstructured environments, this paper proposes a modified tentacle algorithm to ensure the high performance of collision avoidance. Different from the conventional tentacle algorithm which uses inverse derivation, the modified tentacle algorithm rapidly matches the radius of each tentacle and the steering command, ensuring that the data calculation problem in the conventional tentacle algorithm is solved. Meanwhile, both the speed sets and tentacles in one speed set are reduced and reconstructed so as to be applied to multiple UAVs. Instead of path iterative optimization, the paper selects the best tentacle to obtain the UAV collision avoidance path quickly. The simulation results show that the method presented in the paper effectively enhances the performance of flight formation and collision avoidance for multiple high-speed UAVs in unstructured environments.

  3. Dynamic UAV-based traffic monitoring under uncertainty as a stochastic arc-inventory routing policy

    Directory of Open Access Journals (Sweden)

    Joseph Y.J. Chow

    2016-10-01

    Full Text Available Given the rapid advances in unmanned aerial vehicles, or drones, and increasing need to monitor at a city level, one of the current research gaps is how to systematically deploy drones over multiple periods. We propose a real-time data-driven approach: we formulate the first deterministic arc-inventory routing problem and derive its stochastic dynamic policy. The policy is expected to be of greatest value in scenarios where uncertainty is highest and costliest, such as city monitoring during major events. The Bellman equation for an approximation of the proposed inventory routing policy is formulated as a selective vehicle routing problem. We propose an approximate dynamic programming algorithm based on Least Squares Monte Carlo simulation to find that policy. The algorithm has been modified so that the least squares dependent variable is defined to be the “expected stock out cost upon the next replenishment”. The new algorithm is tested on 30 simulated instances of real time trajectories over 5 time periods of the selective vehicle routing problem to evaluate the proposed policy and algorithm. Computational results on the selected instances show that the algorithm on average outperforms the myopic policy by 23–28%, depending on the parametric design. Further tests are conducted on classic benchmark arc routing problem instances. The 11-link instance gdb19 (Golden et al., 1983 is expanded into a sequential 15-period stochastic dynamic example and used to demonstrate why a naïve static multi-period deployment plan would not be effective in real networks.

  4. Simulations of planar pixel sensors for the ATLAS high luminosity upgrade

    CERN Document Server

    Calderini, G; Dinu, N; Lounis, A; Marchiori, G

    2011-01-01

    A physics-based device simulation was used to study the charge carrier distribution and the electric field configuration inside simplified two-dimensional models for pixel layouts based on the ATLAS pixel sensor. In order to study the behavior of such detectors under different levels of irradiation, a three-level defect model was implemented into the simulation. Using these models, the number of guard rings, the dead edge width and the detector thickness were modified to investigate their influence on the detector depletion at the edge and on its internal electric field distribution in order to optimize the layout parameters. Simulations indicate that the number of guard rings can be reduced by a few hundred microns with respect to the layout used for the present ATLAS sensors, with a corresponding extension of the active area of the sensors. A study of the inter-pixel capacitance and of the capacitance between the implants and the high-voltage contact as a function of several parameters affecting the geometr...

  5. Integrated Vehicle Health Management Project-Modeling and Simulation for Wireless Sensor Applications

    Science.gov (United States)

    Wallett, Thomas M.; Mueller, Carl H.; Griner, James H., Jr.

    2009-01-01

    This paper describes the efforts in modeling and simulating electromagnetic transmission and reception as in a wireless sensor network through a realistic wing model for the Integrated Vehicle Health Management project at the Glenn Research Center. A computer model in a standard format for an S-3 Viking aircraft was obtained, converted to a Microwave Studio software format, and scaled to proper dimensions in Microwave Studio. The left wing portion of the model was used with two antenna models, one transmitting and one receiving, to simulate radio frequency transmission through the wing. Transmission and reception results were inconclusive.

  6. Simulation tool for optical design of PET detector modules including scintillator material and sensor array

    Energy Technology Data Exchange (ETDEWEB)

    Jatekos, B.; Erdei, G.; Lorincz, E. [Budapest Univ. of Technology and Economics, Dept. of Atomic Physics, Budafoki ut 8, H-1111 Budapest (Hungary)

    2011-07-01

    The appearance of single photon avalanche diodes (SPADs) in the field of PET detector modules made it necessary to apply more complex optical design methods to refine the performance of such assemblies. We developed a combined simulation tool that is capable to model complex detector structures including scintillation material, light guide, light collection optics and sensor, correctly taking into account the statistical behavior of emission of scintillation light and its absorbance in SPADs. As a validation we compared simulation results obtained by our software and another optical design program. Calculations were performed for a simple PET detector arrangement used for testing purposes. According to the results, deviation of center of gravity coordinates between the two simulations is 0.0195 mm, the average ratio of total counts 1.0052. We investigated the error resulting from finite sampling in wavelength space and we found that 20 nm pitch is sufficient for the simulation in case of the given spectral dependencies. (authors)

  7. Three-Dimensional Temperature and Wind Profiles Obtained Using UAV-Based Acoustic Atmospheric Tomography

    Science.gov (United States)

    Finn, A.

    2017-12-01

    The natural sound generated by an unmanned aerial vehicle is used in conjunction with tomography to remotely sense atmospheric temperature and wind profiles simultaneously. Sound fields recorded onboard the aircraft and by an array of microphones on the ground are compared and converted to sound speed estimates for the ray paths intersecting the intervening medium. Tomographic inversion is then used to transform these sound speed values into vertical cross-sections and 3D volumes of virtual temperature and wind vectors, which enables the atmosphere to be visualised and monitored over time up to altitudes of 1,200m and over baselines of up to 600m. This paper reports on results from two short campaigns during which 2D and 3D profiles of wind and temperature obtained in this way were compared to: measurements taken by co-located mid-range Doppler SODAR and LIDAR; and temperature measurements made by instruments carried by unmanned aircraft flying through the intervening atmosphere. Large eddy simulation of daytime atmospheric boundary layers were also used to examine the anticipated performance of the instruments and the nature of any errors. The observations obtained using all systems are shown to correspond closely.

  8. Design and implementation of a remote UAV-based mobile health monitoring system

    Science.gov (United States)

    Li, Songwei; Wan, Yan; Fu, Shengli; Liu, Mushuang; Wu, H. Felix

    2017-04-01

    Unmanned aerial vehicles (UAVs) play increasing roles in structure health monitoring. With growing mobility in modern Internet-of-Things (IoT) applications, the health monitoring of mobile structures becomes an emerging application. In this paper, we develop a UAV-carried vision-based monitoring system that allows a UAV to continuously track and monitor a mobile infrastructure and transmit back the monitoring information in real- time from a remote location. The monitoring system uses a simple UAV-mounted camera and requires only a single feature located on the mobile infrastructure for target detection and tracking. The computation-effective vision-based tracking solution based on a single feature is an improvement over existing vision-based lead-follower tracking systems that either have poor tracking performance due to the use of a single feature, or have improved tracking performance at a cost of the usage of multiple features. In addition, a UAV-carried aerial networking infrastructure using directional antennas is used to enable robust real-time transmission of monitoring video streams over a long distance. Automatic heading control is used to self-align headings of directional antennas to enable robust communication in mobility. Compared to existing omni-communication systems, the directional communication solution significantly increases the operation range of remote monitoring systems. In this paper, we develop the integrated modeling framework of camera and mobile platforms, design the tracking algorithm, develop a testbed of UAVs and mobile platforms, and evaluate system performance through both simulation studies and field tests.

  9. Simulation-based sensor modeling and at-range target detection characterization with MuSES

    Science.gov (United States)

    Packard, Corey D.; Curran, Allen R.; Saur, Nicholas E.; Rynes, Peter L.

    2015-05-01

    Accurate infrared signature prediction of targets, such as humans or ground vehicles, depends primarily on the realistic prediction of physical temperatures. Thermal model development typically requires a geometric description of the target (i.e., a 3D surface mesh) along with material properties for characterizing the thermal response to simulated weather conditions. Once an accurate thermal solution has been obtained, signature predictions for an EO/IR spectral waveband can be generated. The image rendering algorithm should consider the radiative emissions, diffuse/specular reflections, and atmospheric effects to depict how an object in a natural scene would be perceived by an EO/IR sensor. The EO/IR rendering process within MuSES, developed by ThermoAnalytics, can be used to create a synthetic radiance image that predicts the energy detected by a specific sensor just prior to passing through its optics. For additional realism, blurring due to lens diffraction and noise due to variations in photon detection can also be included, via specification of sensor characteristics. Additionally, probability of detection can be obtained via the Targeting Task Performance (TTP) metric, making it possible to predict a target's at-range detectability to a particular threat sensor. In this paper, we will investigate the at-range contrast and detectability of some example targets and examine the effect of various techniques such as sub-pixel sampling and target pixel thresholding.

  10. Analysis of Simulated Output Characteristics of Gas Sensor Based on Graphene Nanoribbon

    Directory of Open Access Journals (Sweden)

    A. Mahmoudi

    2016-01-01

    Full Text Available This work presents simulated output characteristics of gas sensor transistors based on graphene nanoribbon (GNRFET. The device studied in this work is a new generation of gas sensing devices, which are easy to use, ultracompact, ultrasensitive, and highly selective. We will explain how the exposure to the gas changes the conductivity of graphene nanoribbon. The equations of the GNRFET gas sensor model include the Poisson equation in the weak nonlocality approximation with proposed sensing parameters. As we have developed this model as a platform for a gas detection sensor, we will analyze the current-voltage characteristics after exposure of the GNRFET nanosensor device to NH3 gas. A sensitivity of nearly 2.7% was indicated in our sensor device after exposure of 1 ppm of NH3. The given results make GNRFET the right candidate for use in gas sensing/measuring appliances. Thus, we will investigate the effect of the channel length on the ON- and OFF-current.

  11. FDTD-based optical simulations methodology for CMOS image sensors pixels architecture and process optimization

    Science.gov (United States)

    Hirigoyen, Flavien; Crocherie, Axel; Vaillant, Jérôme M.; Cazaux, Yvon

    2008-02-01

    This paper presents a new FDTD-based optical simulation model dedicated to describe the optical performances of CMOS image sensors taking into account diffraction effects. Following market trend and industrialization constraints, CMOS image sensors must be easily embedded into even smaller packages, which are now equipped with auto-focus and short-term coming zoom system. Due to miniaturization, the ray-tracing models used to evaluate pixels optical performances are not accurate anymore to describe the light propagation inside the sensor, because of diffraction effects. Thus we adopt a more fundamental description to take into account these diffraction effects: we chose to use Maxwell-Boltzmann based modeling to compute the propagation of light, and to use a software with an FDTD-based (Finite Difference Time Domain) engine to solve this propagation. We present in this article the complete methodology of this modeling: on one hand incoherent plane waves are propagated to approximate a product-use diffuse-like source, on the other hand we use periodic conditions to limit the size of the simulated model and both memory and computation time. After having presented the correlation of the model with measurements we will illustrate its use in the case of the optimization of a 1.75μm pixel.

  12. Simulated Effects of Soil Temperature and Salinity on Capacitance Sensor Measurements

    Directory of Open Access Journals (Sweden)

    Timothy R. Green

    2007-04-01

    Full Text Available Dielectric measurement techniques are used widely for estimation of water contentin environmental media. However, factors such as temperature and salinity affecting thereadings require further quantitative investigation and explanation. Theoretical sensitivities ofcapacitance sensors to liquid salinity and temperature of porous media were derived andcomputed using a revised electrical circuit analogue model in conjunction with a dielectricmixing model and a finite element model of Maxwell’s equation to compute electrical fielddistributions. The mixing model estimates the bulk effective complex permittivities of solid-water-air media. The real part of the permittivity values were used in electric field simulations,from which different components of capacitance were calculated via numerical integration forinput to the electrical circuit analogue. Circuit resistances representing the dielectric losses werecalculated from the complex permittivity of the bulk soil and from the modeled fields. Resonantfrequencies from the circuit analogue were used to update frequency-dependent variables in aniterative manner. Simulated resonant frequencies of the capacitance sensor display sensitivitiesto both temperature and salinity. The gradients in normalized frequency with temperatureranged from negative to positive values as salinity increased from 0 to 10 g L-1. The modeldevelopment and analyses improved our understanding of processes affecting the temperatureand salinity sensitivities of capacitance sensors in general. This study provides a foundation forfurther work on inference of soil water content under field conditions.

  13. UAV-BASED PHOTOGRAMMETRIC POINT CLOUDS – TREE STEM MAPPING IN OPEN STANDS IN COMPARISON TO TERRESTRIAL LASER SCANNER POINT CLOUDS

    Directory of Open Access Journals (Sweden)

    A. Fritz

    2013-08-01

    and complete as in the TLS-point cloud. Only few stems were considered to be fully reconstructed. From the comparison of reconstruction achievement with respect to height above ground, we can state that reconstruction accuracy decreased in the crown layer of the stand. In addition we were cutting 50 [cm] slices in z-direction and applied a robust cylinder fit to the stem slices. Radii of the TLS-cloud and the SFM-cloud surprisingly correlated well with a Pearson's correlation coefficient of r = 0.696. This first study showed promising results for UAV-based forest structure modelling. Yet, there is a demand for additional research with regard to vegetation stages, flight pattern, processing setup and the utilisation of spectral information.

  14. Simulation of SAW Humidity Sensors Based on ( 11 2 ¯ 0 ZnO/R-Sapphire Structures

    Directory of Open Access Journals (Sweden)

    Xiao-Dong Lan

    2016-11-01

    Full Text Available The characteristics of two types of surface acoustic waves SAWs (Rayleigh waves and Love waves propagating in bilayered structures of ( 11 2 ¯ 0 ZnO/R-sapphire are simulated by a finite element method (FEM model, in which both SAWs have crossed propagation directions. Furthermore, based on the bilayered structures, the frequency responses of Rayleigh wave and Love wave humidity sensors are also simulated. Meanwhile, the frequency shifts, insertion loss changes and then the sensitivities of both humidity sensors induced by the adsorbed water layer perturbations, including the mechanical and electrical factors, are calculated numerically. Generally, the characteristics and performances of both sensors are strongly dependent on the thickness of the ZnO films. By appropriate selecting the ratio of the film thickness to SAW wavelength for each kind of the sensors, the performances of both sensors can be optimized.

  15. Numerical Simulation of Output Response of PVDF Sensor Attached on a Cantilever Beam Subjected to Impact Loading

    Directory of Open Access Journals (Sweden)

    Cao Vu Dung

    2016-04-01

    Full Text Available Polyvinylidene Flouride (PVDF is a film-type polymer that has been used as sensors and actuators in various applications due to its mechanical toughness, flexibility, and low density. A PVDF sensor typically covers an area of the host structure over which mechanical stress/strain is averaged and converted to electrical energy. This study investigates the fundamental “stress-averaging” mechanism for dynamic strain sensing in the in-plane mode. A numerical simulation was conducted to simulate the “stress-averaging” mechanism of a PVDF sensor attached on a cantilever beam subjected to an impact loading, taking into account the contribution of piezoelectricity, the cantilever beam’s modal properties, and electronic signal conditioning. Impact tests and FEM analysis were also carried out to verify the numerical simulation results. The results of impact tests indicate the excellent capability of the attached PVDF sensor in capturing the fundamental natural frequencies of the cantilever beam. There is a good agreement between the PVDF sensor’s output voltage predicted by the numerical simulation and that obtained in the impact tests. Parametric studies were conducted to investigate the effects of sensor size and sensor position and it is shown that a larger sensor tends to generate higher output voltage than a smaller one at the same location. However, the effect of sensor location seems to be more significant for larger sensors due to the cancelling problem. Overall, PVDF sensors exhibit excellent sensing capability for in-plane dynamic strain induced by impact loading.

  16. The impacts of environmental variables on water reflectance measured using a lightweight unmanned aerial vehicle (UAV)-based spectrometer system

    Science.gov (United States)

    Zeng, Chuiqing; Richardson, Murray; King, Douglas J.

    2017-08-01

    contribute to better understanding of water reflectance acquisition using remote sensing, and can be applied in UAV-based water quality assessment or to aid in validation of higher altitude imagery.

  17. Quantifying pruning impacts on olive tree architecture and annual canopy growth by using UAV-based 3D modelling.

    Science.gov (United States)

    Jiménez-Brenes, F M; López-Granados, F; de Castro, A I; Torres-Sánchez, J; Serrano, N; Peña, J M

    2017-01-01

    Tree pruning is a costly practice with important implications for crop harvest and nutrition, pest and disease control, soil protection and irrigation strategies. Investigations on tree pruning usually involve tedious on-ground measurements of the primary tree crown dimensions, which also might generate inconsistent results due to the irregular geometry of the trees. As an alternative to intensive field-work, this study shows a innovative procedure based on combining unmanned aerial vehicle (UAV) technology and advanced object-based image analysis (OBIA) methodology for multi-temporal three-dimensional (3D) monitoring of hundreds of olive trees that were pruned with three different strategies (traditional, adapted and mechanical pruning). The UAV images were collected before pruning, after pruning and a year after pruning, and the impacts of each pruning treatment on the projected canopy area, tree height and crown volume of every tree were quantified and analyzed over time. The full procedure described here automatically identified every olive tree on the orchard and computed their primary 3D dimensions on the three study dates with high accuracy in the most cases. Adapted pruning was generally the most aggressive treatment in terms of the area and volume (the trees decreased by 38.95 and 42.05% on average, respectively), followed by trees under traditional pruning (33.02 and 35.72% on average, respectively). Regarding the tree heights, mechanical pruning produced a greater decrease (12.15%), and these values were minimal for the other two treatments. The tree growth over one year was affected by the pruning severity and by the type of pruning treatment, i.e., the adapted-pruning trees experienced higher growth than the trees from the other two treatments when pruning intensity was low (UAV-based images and an OBIA procedure allowed measuring tree dimensions and quantifying the impacts of three different pruning treatments on hundreds of trees with minimal field

  18. Modeling and simulation of the transient response of temperature and relative humidity sensors with and without protective housing.

    Science.gov (United States)

    Rocha, Keller Sullivan Oliveira; Martins, José Helvecio; Martins, Marcio Arêdes; Tinôco, Ilda de Fátima Ferreira; Saraz, Jairo Alexander Osorio; Lacerda Filho, Adílio Flauzino; Fernandes, Luiz Henrique Martins

    2014-01-01

    Based on the necessity for enclosure protection of temperature and relative humidity sensors installed in a hostile environment, a wind tunnel was used to quantify the time that the sensors take to reach equilibrium in the environmental conditions to which they are exposed. Two treatments were used: (1) sensors with polyvinyl chloride (PVC) enclosure protection, and (2) sensors with no enclosure protection. The primary objective of this study was to develop and validate a 3-D computational fluid dynamics (CFD) model for analyzing the temperature and relative humidity distribution in a wind tunnel using sensors with PVC enclosure protection and sensors with no enclosure protection. A CFD simulation model was developed to describe the temperature distribution and the physics of mass transfer related to the airflow relative humidity. The first results demonstrate the applicability of the simulation. For verification, a sensor device was successfully assembled and tested in an environment that was optimized to ensure fast change conditions. The quantification setup presented in this paper is thus considered to be adequate for testing different materials and morphologies for enclosure protection. The results show that the boundary layer flow regime has a significant impact on the heat flux distribution. The results indicate that the CFD technique is a powerful tool which provides a detailed description of the flow and temperature fields as well as the time that the relative humidity takes to reach equilibrium with the environment in which the sensors are inserted.

  19. Modeling and Simulation of the Transient Response of Temperature and Relative Humidity Sensors with and without Protective Housing

    Science.gov (United States)

    Rocha, Keller Sullivan Oliveira; Martins, José Helvecio; Martins, Marcio Arêdes; Ferreira Tinôco, Ilda de Fátima; Saraz, Jairo Alexander Osorio; Filho, Adílio Flauzino Lacerda; Fernandes, Luiz Henrique Martins

    2014-01-01

    Based on the necessity for enclosure protection of temperature and relative humidity sensors installed in a hostile environment, a wind tunnel was used to quantify the time that the sensors take to reach equilibrium in the environmental conditions to which they are exposed. Two treatments were used: (1) sensors with polyvinyl chloride (PVC) enclosure protection, and (2) sensors with no enclosure protection. The primary objective of this study was to develop and validate a 3-D computational fluid dynamics (CFD) model for analyzing the temperature and relative humidity distribution in a wind tunnel using sensors with PVC enclosure protection and sensors with no enclosure protection. A CFD simulation model was developed to describe the temperature distribution and the physics of mass transfer related to the airflow relative humidity. The first results demonstrate the applicability of the simulation. For verification, a sensor device was successfully assembled and tested in an environment that was optimized to ensure fast change conditions. The quantification setup presented in this paper is thus considered to be adequate for testing different materials and morphologies for enclosure protection. The results show that the boundary layer flow regime has a significant impact on the heat flux distribution. The results indicate that the CFD technique is a powerful tool which provides a detailed description of the flow and temperature fields as well as the time that the relative humidity takes to reach equilibrium with the environment in which the sensors are inserted. PMID:24851994

  20. Simulation of Greenhouse Climate Monitoring and Control with Wireless Sensor Network and Event-Based Control

    Directory of Open Access Journals (Sweden)

    Andrzej Pawlowski

    2009-01-01

    Full Text Available Monitoring and control of the greenhouse environment play a decisive role in greenhouse production processes. Assurance of optimal climate conditions has a direct influence on crop growth performance, but it usually increases the required equipment cost. Traditionally, greenhouse installations have required a great effort to connect and distribute all the sensors and data acquisition systems. These installations need many data and power wires to be distributed along the greenhouses, making the system complex and expensive. For this reason, and others such as unavailability of distributed actuators, only individual sensors are usually located in a fixed point that is selected as representative of the overall greenhouse dynamics. On the other hand, the actuation system in greenhouses is usually composed by mechanical devices controlled by relays, being desirable to reduce the number of commutations of the control signals from security and economical point of views. Therefore, and in order to face these drawbacks, this paper describes how the greenhouse climate control can be represented as an event-based system in combination with wireless sensor networks, where low-frequency dynamics variables have to be controlled and control actions are mainly calculated against events produced by external disturbances. The proposed control system allows saving costs related with wear minimization and prolonging the actuator life, but keeping promising performance results. Analysis and conclusions are given by means of simulation results.

  1. Toward the Computational Representation of Individual Cultural, Cognitive, and Physiological State: The Sensor Shooter Simulation; TOPICAL

    International Nuclear Information System (INIS)

    RAYBOURN, ELAINE M.; FORSYTHE, JAMES C.

    2001-01-01

    This report documents an exploratory FY 00 LDRD project that sought to demonstrate the first steps toward a realistic computational representation of the variability encountered in individual human behavior. Realism, as conceptualized in this project, required that the human representation address the underlying psychological, cultural, physiological, and environmental stressors. The present report outlines the researchers' approach to representing cognitive, cultural, and physiological variability of an individual in an ambiguous situation while faced with a high-consequence decision that would greatly impact subsequent events. The present project was framed around a sensor-shooter scenario as a soldier interacts with an unexpected target (two young Iraqi girls). A software model of the ''Sensor Shooter'' scenario from Desert Storm was developed in which the framework consisted of a computational instantiation of Recognition Primed Decision Making in the context of a Naturalistic Decision Making model[1]. Recognition Primed Decision Making was augmented with an underlying foundation based on our current understanding of human neurophysiology and its relationship to human cognitive processes. While the Gulf War scenario that constitutes the framework for the Sensor Shooter prototype is highly specific, the human decision architecture and the subsequent simulation are applicable to other problems similar in concept, intensity, and degree of uncertainty. The goal was to provide initial steps toward a computational representation of human variability in cultural, cognitive, and physiological state in order to attain a better understanding of the full depth of human decision-making processes in the context of ambiguity, novelty, and heightened arousal

  2. The Characterization of a DIRSIG Simulation Environment to Support the Inter-Calibration of Spaceborne Sensors

    Science.gov (United States)

    Ambeau, Brittany L.; Gerace, Aaron D.; Montanaro, Matthew; McCorkel, Joel

    2016-01-01

    Climate change studies require long-term, continuous records that extend beyond the lifetime, and the temporal resolution, of a single remote sensing satellite sensor. The inter-calibration of spaceborne sensors is therefore desired to provide spatially, spectrally, and temporally homogeneous datasets. The Digital Imaging and Remote Sensing Image Generation (DIRSIG) tool is a first principle-based synthetic image generation model that has the potential to characterize the parameters that impact the accuracy of the inter-calibration of spaceborne sensors. To demonstrate the potential utility of the model, we compare the radiance observed in real image data to the radiance observed in simulated image from DIRSIG. In the present work, a synthetic landscape of the Algodones Sand Dunes System is created. The terrain is facetized using a 2-meter digital elevation model generated from NASA Goddard's LiDAR, Hyperspectral, and Thermal (G-LiHT) imager. The material spectra are assigned using hyperspectral measurements of sand collected from the Algodones Sand Dunes System. Lastly, the bidirectional reflectance distribution function (BRDF) properties are assigned to the modeled terrain using the Moderate Resolution Imaging Spectroradiometer (MODIS) BRDF product in conjunction with DIRSIG's Ross-Li capability. The results of this work indicate that DIRSIG is in good agreement with real image data. The potential sources of residual error are identified and the possibilities for future work are discussed..

  3. Detection of protease activity by fluorescent protein FRET sensors: from computer simulation to live cells

    Science.gov (United States)

    Goryashchenko, Alexander S.; Khrenova, Maria G.; Savitsky, Alexander P.

    2018-04-01

    Förster resonance energy transfer (FRET) sensors are widely used for the detection of protease activity in vitro and in vivo. Usually they consist of a FRET pair connected with a polypeptide linker containing a specific cleavage site for the relevant protease. Use of the fluorescent proteins as components of the FRET pair allows genetic encoding of such sensors and solves the problem of their delivery into live cells and animals. There are several ways to improve the properties of such sensors, mainly to increase FRET efficiency and therefore the dynamic range. One of the ways to achieve this is to use a non-fluorescent chromoprotein as an acceptor. Molecular dynamic simulations may assist in the construction of linker structures connecting donor and acceptor molecules. Estimation of the orientation factor κ 2 can be obtained by methods based on quantum theory and combined quantum mechanics/molecular mechanics approaches. The linker can be structured by hydrophobic interactions, bringing it into a closed conformation that shortens the distance between donor and acceptor and, consequently, increases FRET efficiency. We analyzed the effects of different linker structures on the detection of caspase-3 activity using a non-fluorescent acceptor. Also we have constructed the Tb3+- TagRFP sensor in which a complex of the terbium ion and terbium-binding peptide is used as a donor. This allowed us to use the unique property of lanthanide ions—fluorescence lifetime up to milliseconds—to perform measurements with time delay and exclude the nanosecond-order fluorescence. Using our systems as a starting point, by changing the recognition site in the linker it is possible to perform imaging of different protease activity in vitro or in vivo.

  4. Geant4-based simulations of charge collection in CMOS Active Pixel Sensors

    International Nuclear Information System (INIS)

    Esposito, M.; Allinson, N.M.; Price, T.; Anaxagoras, T.

    2017-01-01

    Geant4 is an object-oriented toolkit for the simulation of the interaction of particles and radiation with matter. It provides a snapshot of the state of a simulated particle in time, as it travels through a specified geometry. One important area of application is the modelling of radiation detector systems. Here, we extend the abilities of such modelling to include charge transport and sharing in pixelated CMOS Active Pixel Sensors (APSs); though similar effects occur in other pixel detectors. The CMOS APSs discussed were developed in the framework of the PRaVDA consortium to assist the design of custom sensors to be used in an energy-range detector for proton Computed Tomography (pCT). The development of ad-hoc classes, providing a charge transport model for a CMOS APS and its integration into the standard Geant4 toolkit, is described. The proposed charge transport model includes, charge generation, diffusion, collection, and sharing across adjacent pixels, as well as the full electronic chain for a CMOS APS. The proposed model is validated against experimental data acquired with protons in an energy range relevant for pCT.

  5. Simulation and Implementation of a Morphology-Tuned Gold Nano-Islands Integrated Plasmonic Sensor

    Directory of Open Access Journals (Sweden)

    Jayan Ozhikandathil

    2014-06-01

    Full Text Available This work presents simulation, analysis and implementation of morphology tuning of gold nano-island structures deposited by a novel convective assembly technique. The gold nano-islands were simulated using 3D Finite-Difference Time-Domain (FDTD techniques to investigate the effect of morphological changes and adsorption of protein layers on the localized surface plasmon resonance (LSPR properties. Gold nano-island structures were deposited on glass substrates by a novel and low-cost convective assembly process. The structure formed by an uncontrolled deposition method resulted in a nano-cluster morphology, which was annealed at various temperatures to tune the optical absorbance properties by transforming the nano-clusters to a nano-island morphology by modifying the structural shape and interparticle separation distances. The dependence of the size and the interparticle separation distance of the nano-islands on the LSPR properties were analyzed in the simulation. The effect of adsorption of protein layer on the nano-island structures was simulated and a relation between the thickness and the refractive index of the protein layer on the LSPR peak was presented. Further, the sensitivity of the gold nano-island integrated sensor against refractive index was computed and compared with the experimental results.

  6. Graphene Nanoplatelet-Polymer Chemiresistive Sensor Arrays for the Detection and Discrimination of Chemical Warfare Agent Simulants.

    Science.gov (United States)

    Wiederoder, Michael S; Nallon, Eric C; Weiss, Matt; McGraw, Shannon K; Schnee, Vincent P; Bright, Collin J; Polcha, Michael P; Paffenroth, Randy; Uzarski, Joshua R

    2017-11-22

    A cross-reactive array of semiselective chemiresistive sensors made of polymer-graphene nanoplatelet (GNP) composite coated electrodes was examined for detection and discrimination of chemical warfare agents (CWA). The arrays employ a set of chemically diverse polymers to generate a unique response signature for multiple CWA simulants and background interferents. The developed sensors' signal remains consistent after repeated exposures to multiple analytes for up to 5 days with a similar signal magnitude across different replicate sensors with the same polymer-GNP coating. An array of 12 sensors each coated with a different polymer-GNP mixture was exposed 100 times to a cycle of single analyte vapors consisting of 5 chemically similar CWA simulants and 8 common background interferents. The collected data was vector normalized to reduce concentration dependency, z-scored to account for baseline drift and signal-to-noise ratio, and Kalman filtered to reduce noise. The processed data was dimensionally reduced with principal component analysis and analyzed with four different machine learning algorithms to evaluate discrimination capabilities. For 5 similarly structured CWA simulants alone 100% classification accuracy was achieved. For all analytes tested 99% classification accuracy was achieved demonstrating the CWA discrimination capabilities of the developed system. The novel sensor fabrication methods and data processing techniques are attractive for development of sensor platforms for discrimination of CWA and other classes of chemical vapors.

  7. Design and simulation of betavoltaic angle sensor Based on 63Ni–Si

    International Nuclear Information System (INIS)

    Ghasemi Nejad, Gholam Reza; Rahmani, Faezeh

    2016-01-01

    A theoretical design and simulation of betavoltaic angle sensor (beta-AS) based on 63 Ni–Si using MCNP code is presented in this article. It can measure the full angle of 0–360° in the temperature range of 233–353 K. Beta-AS is composed of semicircular 63 Ni as the beta source, which rotates along the circular (four-quadrant) surface of Si as a semiconductor (in p–n structure), so that the change in the source angle in relation to Si surface can be measured based on the changes in V oc observed in each quadrant of Si. For better performance, characteristics of Si and 63 Ni have been optimized: N D and N A values of 8e19 and 4e18 cm −3 (donor and acceptor doping concentration in Si, respectively), source thickness and activity of 1.5 µm and 18 mCi, respectively. The relation between angle and V oc is also investigated. The maximum difference between measured and real values of angle (the worst case, i.e., 0.18° for the angle of 45°) occurs at 233 K. It has been shown that sensitivity of the sensor decreases with an increase of angle. The results also show that the change in activity does not affect the sensitivity. - Highlights: • The angle sensor based on 63 Ni–Si in small dimensions for operating in the wide range of temperature and full-angle measurement was proposed. • The rate of electron–hole pair generation in silicon was obtained using Monte Carlo MCNP4C code. • Effects of temperature and activity on the accuracy of the measurement of angle were investigated. • Temperature calibration was considered simultaneously in the proposed structure (self-correcting).

  8. Simulation of Image Performance Characteristics of the Landsat Data Continuity Mission (LDCM) Thermal Infrared Sensor (TIRS)

    Science.gov (United States)

    Schott, John; Gerace, Aaron; Brown, Scott; Gartley, Michael; Montanaro, Matthew; Reuter, Dennis C.

    2012-01-01

    The next Landsat satellite, which is scheduled for launch in early 2013, will carry two instruments: the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS). Significant design changes over previous Landsat instruments have been made to these sensors to potentially enhance the quality of Landsat image data. TIRS, which is the focus of this study, is a dual-band instrument that uses a push-broom style architecture to collect data. To help understand the impact of design trades during instrument build, an effort was initiated to model TIRS imagery. The Digital Imaging and Remote Sensing Image Generation (DIRSIG) tool was used to produce synthetic "on-orbit" TIRS data with detailed radiometric, geometric, and digital image characteristics. This work presents several studies that used DIRSIG simulated TIRS data to test the impact of engineering performance data on image quality in an effort to determine if the image data meet specifications or, in the event that they do not, to determine if the resulting image data are still acceptable.

  9. Multiple Sensing Application on Wireless Sensor Network Simulation using NS3

    Science.gov (United States)

    Kurniawan, I. F.; Bisma, R.

    2018-01-01

    Hardware enhancement provides opportunity to install various sensor device on single monitoring node which then enables users to acquire multiple data simultaneously. Constructing multiple sensing application in NS3 is a challenging task since numbers of aspects such as wireless communication, packet transmission pattern, and energy model must be taken into account. Despite of numerous types of monitoring data available, this study only considers two types such as periodic, and event-based data. Periodical data will generate monitoring data follows configured interval, while event-based transmit data when certain determined condition is met. Therefore, this study attempts to cover mentioned aspects in NS3. Several simulations are performed with different number of nodes on arbitrary communication scheme.

  10. 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

  11. Simulation of a sensor array for multiparameter measurements at the prosthetic limb interface

    Science.gov (United States)

    Rowe, Gabriel I.; Mamishev, Alexander V.

    2004-07-01

    Sensitive skin is a highly desired device for biomechanical devices, wearable computing, human-computer interfaces, exoskeletons, and, most pertinent to this paper, for lower limb prosthetics. The measurement of shear stress is very important because shear effects are key factors in developing surface abrasions and pressure sores in paraplegics and users of prosthetic/orthotic devices. A single element of a sensitive skin is simulated and characterized in this paper. Conventional tactile sensors are designed for measurement of the normal stress only, which is inadequate for comprehensive assessment of surface contact conditions. The sensitive skin discussed here is a flexible array capable of sensing shear and normal forces, as well as humidity and temperature on each element.

  12. A new and efficient transient noise analysis technique for simulation of CCD image sensors or particle detectors

    International Nuclear Information System (INIS)

    Bolcato, P.; Jarron, P.; Poujois, R.

    1993-01-01

    CCD image sensors or switched capacitor circuits used for particle detectors have a certain noise level affecting the resolution of the detector. A new noise simulation technique for these devices is presented that has been implemented in the circuit simulator ELDO. The approach is particularly useful for noise simulation in analog sampling circuits. Comparison between simulations and experimental results has been made and is shown for a 1.5 μ CMOS current mode amplifier designed for high-rate particle detectors. (R.P.) 5 refs., 7 figs

  13. Simulation-Driven Development and Optimization of a High-Performance Six-Dimensional Wrist Force/Torque Sensor

    Directory of Open Access Journals (Sweden)

    Qiaokang LIANG

    2010-05-01

    Full Text Available This paper describes the Simulation-Driven Development and Optimization (SDDO of a six-dimensional force/torque sensor with high performance. By the implementation of the SDDO, the developed sensor possesses high performance such as high sensitivity, linearity, stiffness and repeatability simultaneously, which is hard for tranditional force/torque sensor. Integrated approach provided by software ANSYS was used to streamline and speed up the process chain and thereby to deliver results significantly faster than traditional approaches. The result of calibration experiment possesses some impressive characters, therefore the developed fore/torque sensor can be usefully used in industry and the methods of design can also be used to develop industrial product.

  14. A fibre optic oxygen sensor that detects rapid PO2 changes under simulated conditions of cyclical atelectasis in vitro.

    Science.gov (United States)

    Formenti, Federico; Chen, Rongsheng; McPeak, Hanne; Matejovic, Martin; Farmery, Andrew D; Hahn, Clive E W

    2014-01-15

    Two challenges in the management of Acute Respiratory Distress Syndrome are the difficulty in diagnosing cyclical atelectasis, and in individualising mechanical ventilation therapy in real-time. Commercial optical oxygen sensors can detect [Formula: see text] oscillations associated with cyclical atelectasis, but are not accurate at saturation levels below 90%, and contain a toxic fluorophore. We present a computer-controlled test rig, together with an in-house constructed ultra-rapid sensor to test the limitations of these sensors when exposed to rapidly changing [Formula: see text] in blood in vitro. We tested the sensors' responses to simulated respiratory rates between 10 and 60 breaths per minute. Our sensor was able to detect the whole amplitude of the imposed [Formula: see text] oscillations, even at the highest respiratory rate. We also examined our sensor's resistance to clot formation by continuous in vivo deployment in non-heparinised flowing animal blood for 24h, after which no adsorption of organic material on the sensor's surface was detectable by scanning electron microscopy. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  15. ABS-FishCount: An Agent-Based Simulator of Underwater Sensors for Measuring the Amount of Fish.

    Science.gov (United States)

    García-Magariño, Iván; Lacuesta, Raquel; Lloret, Jaime

    2017-11-13

    Underwater sensors provide one of the possibilities to explore oceans, seas, rivers, fish farms and dams, which all together cover most of our planet's area. Simulators can be helpful to test and discover some possible strategies before implementing these in real underwater sensors. This speeds up the development of research theories so that these can be implemented later. In this context, the current work presents an agent-based simulator for defining and testing strategies for measuring the amount of fish by means of underwater sensors. The current approach is illustrated with the definition and assessment of two strategies for measuring fish. One of these two corresponds to a simple control mechanism, while the other is an experimental strategy and includes an implicit coordination mechanism. The experimental strategy showed a statistically significant improvement over the control one in the reduction of errors with a large Cohen's d effect size of 2.55.

  16. Design and Simulation Test of an Open D-Dot Voltage Sensor

    Directory of Open Access Journals (Sweden)

    Yunjie Bai

    2015-09-01

    Full Text Available Nowadays, sensor development focuses on miniaturization and non-contact measurement. According to the D-dot principle, a D-dot voltage sensor with a new structure was designed based on the differential D-dot sensor with a symmetrical structure, called an asymmetric open D-dot voltage sensor. It is easier to install. The electric field distribution of the sensor was analyzed through Ansoft Maxwell and an open D-dot voltage sensor was designed. This open D-voltage sensor is characteristic of accessible insulating strength and small electric field distortion. The steady and transient performance test under 10 kV-voltage reported satisfying performances of the designed open D-dot voltage sensor. It conforms to requirements for a smart grid measuring sensor in intelligence, miniaturization and facilitation.

  17. Development and simulation of microfluidic Wheatstone bridge for high-precision sensor

    Science.gov (United States)

    Shipulya, N. D.; Konakov, S. A.; Krzhizhanovskaya, V. V.

    2016-08-01

    In this work we present the results of analytical modeling and 3D computer simulation of microfluidic Wheatstone bridge, which is used for high-accuracy measurements and precision instruments. We propose and simulate a new method of a bridge balancing process by changing the microchannel geometry. This process is based on the “etching in microchannel” technology we developed earlier (doi:10.1088/1742-6596/681/1/012035). Our method ensures a precise control of the flow rate and flow direction in the bridge microchannel. The advantage of our approach is the ability to work without any control valves and other active electronic systems, which are usually used for bridge balancing. The geometrical configuration of microchannels was selected based on the analytical estimations. A detailed 3D numerical model was based on Navier-Stokes equations for a laminar fluid flow at low Reynolds numbers. We investigated the behavior of the Wheatstone bridge under different process conditions; found a relation between the channel resistance and flow rate through the bridge; and calculated the pressure drop across the system under different total flow rates and viscosities. Finally, we describe a high-precision microfluidic pressure sensor that employs the Wheatstone bridge and discuss other applications in complex precision microfluidic systems.

  18. A new framework for UAV-based remote sensing data processing and its application in almond water stress quantification

    Science.gov (United States)

    With the rapid development of small imaging sensors and unmanned aerial vehicles (UAVs), remote sensing is undergoing a revolution with greatly increased spatial and temporal resolutions. While more relevant detail becomes available, it is a challenge to analyze the large number of images to extract...

  19. Simulation and measurement of total ionizing dose radiation induced image lag increase in pinned photodiode CMOS image sensors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jing [School of Materials Science and Engineering, Xiangtan University, Hunan (China); State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an (China); Chen, Wei, E-mail: chenwei@nint.ac.cn [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an (China); Wang, Zujun, E-mail: wangzujun@nint.ac.cn [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an (China); Xue, Yuanyuan; Yao, Zhibin; He, Baoping; Ma, Wuying; Jin, Junshan; Sheng, Jiangkun; Dong, Guantao [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an (China)

    2017-06-01

    This paper presents an investigation of total ionizing dose (TID) induced image lag sources in pinned photodiodes (PPD) CMOS image sensors based on radiation experiments and TCAD simulation. The radiation experiments have been carried out at the Cobalt −60 gamma-ray source. The experimental results show the image lag degradation is more and more serious with increasing TID. Combining with the TCAD simulation results, we can confirm that the junction of PPD and transfer gate (TG) is an important region forming image lag during irradiation. These simulations demonstrate that TID can generate a potential pocket leading to incomplete transfer.

  20. Reliable before-fabrication forecasting of normal and touch mode MEMS capacitive pressure sensor: modeling and simulation

    Science.gov (United States)

    Jindal, Sumit Kumar; Mahajan, Ankush; Raghuwanshi, Sanjeev Kumar

    2017-10-01

    An analytical model and numerical simulation for the performance of MEMS capacitive pressure sensors in both normal and touch modes is required for expected behavior of the sensor prior to their fabrication. Obtaining such information should be based on a complete analysis of performance parameters such as deflection of diaphragm, change of capacitance when the diaphragm deflects, and sensitivity of the sensor. In the literature, limited work has been carried out on the above-stated issue; moreover, due to approximation factors of polynomials, a tolerance error cannot be overseen. Reliable before-fabrication forecasting requires exact mathematical calculation of the parameters involved. A second-order polynomial equation is calculated mathematically for key performance parameters of both modes. This eliminates the approximation factor, and an exact result can be studied, maintaining high accuracy. The elimination of approximation factors and an approach of exact results are based on a new design parameter (δ) that we propose. The design parameter gives an initial hint to the designers on how the sensor will behave once it is fabricated. The complete work is aided by extensive mathematical detailing of all the parameters involved. Next, we verified our claims using MATLAB® simulation. Since MATLAB® effectively provides the simulation theory for the design approach, more complicated finite element method is not used.

  1. Simulation of a model nanopore sensor: Ion competition underlies device behavior

    Science.gov (United States)

    Mádai, Eszter; Valiskó, Mónika; Dallos, András; Boda, Dezső

    2017-12-01

    We study a model nanopore sensor with which a very low concentration of analyte molecules can be detected on the basis of the selective binding of the analyte molecules to the binding sites on the pore wall. The bound analyte ions partially replace the current-carrier cations in a thermodynamic competition. This competition depends both on the properties of the nanopore and the concentrations of the competing ions (through their chemical potentials). The output signal given by the device is the current reduction caused by the presence of the analyte ions. The concentration of the analyte ions can be determined through calibration curves. We model the binding site with the square-well potential and the electrolyte as charged hard spheres in an implicit background solvent. We study the system with a hybrid method in which we compute the ion flux with the Nernst-Planck (NP) equation coupled with the Local Equilibrium Monte Carlo (LEMC) simulation technique. The resulting NP+LEMC method is able to handle both strong ionic correlations inside the pore (including finite size of ions) and bulk concentrations as low as micromolar. We analyze the effect of bulk ion concentrations, pore parameters, binding site parameters, electrolyte properties, and voltage on the behavior of the device.

  2. Thermoreflectance temperature imaging of integrated circuits: calibration technique and quantitative comparison with integrated sensors and simulations

    International Nuclear Information System (INIS)

    Tessier, G; Polignano, M-L; Pavageau, S; Filloy, C; Fournier, D; Cerutti, F; Mica, I

    2006-01-01

    Camera-based thermoreflectance microscopy is a unique tool for high spatial resolution thermal imaging of working integrated circuits. However, a calibration is necessary to obtain quantitative temperatures on the complex surface of integrated circuits. The spatial and temperature resolutions reached by thermoreflectance are excellent (360 nm and 2.5 x 10 -2 K in 1 min here), but the precision is more difficult to assess, notably due to the lack of comparable thermal techniques at submicron scales. We propose here a Peltier element control of the whole package temperature in order to obtain calibration coefficients simultaneously on several materials visible on the surface of the circuit. Under high magnifications, movements associated with thermal expansion are corrected using a piezo electric displacement and a software image shift. This calibration method has been validated by comparison with temperatures measured using integrated thermistors and diodes and by a finite volume simulation. We show that thermoreflectance measurements agree within a precision of ±2.3% with the on-chip sensors measurements. The diode temperature is found to underestimate the actual temperature of the active area by almost 70% due to the thermal contact of the diode with the substrate, acting as a heat sink

  3. A Theoretical Study and Numerical Simulation of a Quasi-Distributed Sensor Based on the Low-Finesse Fabry-Perot Interferometer: Frequency-Division Multiplexing.

    Science.gov (United States)

    Guillen Bonilla, José Trinidad; Guillen Bonilla, Alex; Rodríguez Betancourtt, Verónica M; Guillen Bonilla, Héctor; Casillas Zamora, Antonio

    2017-04-14

    The application of the sensor optical fibers in the areas of scientific instrumentation and industrial instrumentation is very attractive due to its numerous advantages. In the industry of civil engineering for example, quasi-distributed sensors made with optical fiber are used for reliable strain and temperature measurements. Here, a quasi-distributed sensor in the frequency domain is discussed. The sensor consists of a series of low-finesse Fabry-Perot interferometers where each Fabry-Perot interferometer acts as a local sensor. Fabry-Perot interferometers are formed by pairs of identical low reflective Bragg gratings imprinted in a single mode fiber. All interferometer sensors have different cavity length, provoking frequency-domain multiplexing. The optical signal represents the superposition of all interference patterns which can be decomposed using the Fourier transform. The frequency spectrum was analyzed and sensor's properties were defined. Following that, a quasi-distributed sensor was numerically simulated. Our sensor simulation considers sensor properties, signal processing, noise system, and instrumentation. The numerical results show the behavior of resolution vs. signal-to-noise ratio. From our results, the Fabry-Perot sensor has high resolution and low resolution. Both resolutions are conceivable because the Fourier Domain Phase Analysis (FDPA) algorithm elaborates two evaluations of Bragg wavelength shift.

  4. Bias Impact Analysis and Calibration of UAV-Based Mobile LiDAR System with Spinning Multi-Beam Laser Scanner

    Directory of Open Access Journals (Sweden)

    Radhika Ravi

    2018-02-01

    Full Text Available Light Detection and Ranging (LiDAR is a technology that uses laser beams to measure ranges and generates precise 3D information about the scanned area. It is rapidly gaining popularity due to its contribution to a variety of applications such as Digital Building Model (DBM generation, telecommunications, infrastructure monitoring, transportation corridor asset management and crash/accident scene reconstruction. To derive point clouds with high positional accuracy, estimation of mounting parameters relating the laser scanners to the onboard Global Navigation Satellite System/Inertial Navigation System (GNSS/INS unit, i.e., the lever-arm and boresight angles, is the foremost and necessary step. This paper proposes a LiDAR system calibration strategy for a Unmanned Aerial Vehicle (UAV-based mobile mapping system that can directly estimate the mounting parameters for spinning multi-beam laser scanners through an outdoor calibration procedure. This approach is based on the use of conjugate planar/linear features in overlapping point clouds derived from different flight lines. Designing an optimal configuration for calibration is the first and foremost step in order to ensure the most accurate estimates of mounting parameters. This is achieved by conducting a rigorous theoretical analysis of the potential impact of bias in mounting parameters of a LiDAR unit on the resultant point cloud. The dependency of the impact on the orientation of target primitives and relative flight line configuration would help in deducing the configuration that would maximize as well as decouple the impact of bias in each mounting parameter so as to ensure their accurate estimation. Finally, the proposed analysis and calibration strategy are validated by calibrating a UAV-based LiDAR system using two different datasets—one acquired with flight lines at a single flying height and the other with flight lines at two different flying heights. The calibration performance is

  5. MULTI-TEMPORAL CROP SURFACE MODELS COMBINED WITH THE RGB VEGETATION INDEX FROM UAV-BASED IMAGES FOR FORAGE MONITORING IN GRASSLAND

    Directory of Open Access Journals (Sweden)

    M. Possoch

    2016-06-01

    Full Text Available Remote sensing of crop biomass is important in regard to precision agriculture, which aims to improve nutrient use efficiency and to develop better stress and disease management. In this study, multi-temporal crop surface models (CSMs were generated from UAV-based dense imaging in order to derive plant height distribution and to determine forage mass. The low-cost UAV-based RGB imaging was carried out in a grassland experiment at the University of Bonn, Germany, in summer 2015. The test site comprised three consecutive growths including six different nitrogen fertilizer levels and three replicates, in sum 324 plots with a size of 1.5×1.5 m. Each growth consisted of six harvesting dates. RGB-images and biomass samples were taken at twelve dates nearly biweekly within two growths between June and September 2015. Images were taken with a DJI Phantom 2 in combination of a 2D Zenmuse gimbal and a GoPro Hero 3 (black edition. Overlapping images were captured in 13 to 16 m and overview images in approximately 60 m height at 2 frames per second. The RGB vegetation index (RGBVI was calculated as the normalized difference of the squared green reflectance and the product of blue and red reflectance from the non-calibrated images. The post processing was done with Agisoft PhotoScan Professional (SfM-based and Esri ArcGIS. 14 ground control points (GCPs were located in the field, distinguished by 30 cm × 30 cm markers and measured with a RTK-GPS (HiPer Pro Topcon with 0.01 m horizontal and vertical precision. The errors of the spatial resolution in x-, y-, z-direction were in a scale of 3-4 cm. From each survey, also one distortion corrected image was georeferenced by the same GCPs and used for the RGBVI calculation. The results have been used to analyse and evaluate the relationship between estimated plant height derived with this low-cost UAV-system and forage mass. Results indicate that the plant height seems to be a suitable indicator for forage mass

  6. Multi-Temporal Crop Surface Models Combined with the RGB Vegetation Index from Uav-Based Images for Forage Monitoring in Grassland

    Science.gov (United States)

    Possoch, M.; Bieker, S.; Hoffmeister, D.; Bolten, A.; Schellberg, J.; Bareth, G.

    2016-06-01

    Remote sensing of crop biomass is important in regard to precision agriculture, which aims to improve nutrient use efficiency and to develop better stress and disease management. In this study, multi-temporal crop surface models (CSMs) were generated from UAV-based dense imaging in order to derive plant height distribution and to determine forage mass. The low-cost UAV-based RGB imaging was carried out in a grassland experiment at the University of Bonn, Germany, in summer 2015. The test site comprised three consecutive growths including six different nitrogen fertilizer levels and three replicates, in sum 324 plots with a size of 1.5×1.5 m. Each growth consisted of six harvesting dates. RGB-images and biomass samples were taken at twelve dates nearly biweekly within two growths between June and September 2015. Images were taken with a DJI Phantom 2 in combination of a 2D Zenmuse gimbal and a GoPro Hero 3 (black edition). Overlapping images were captured in 13 to 16 m and overview images in approximately 60 m height at 2 frames per second. The RGB vegetation index (RGBVI) was calculated as the normalized difference of the squared green reflectance and the product of blue and red reflectance from the non-calibrated images. The post processing was done with Agisoft PhotoScan Professional (SfM-based) and Esri ArcGIS. 14 ground control points (GCPs) were located in the field, distinguished by 30 cm × 30 cm markers and measured with a RTK-GPS (HiPer Pro Topcon) with 0.01 m horizontal and vertical precision. The errors of the spatial resolution in x-, y-, z-direction were in a scale of 3-4 cm. From each survey, also one distortion corrected image was georeferenced by the same GCPs and used for the RGBVI calculation. The results have been used to analyse and evaluate the relationship between estimated plant height derived with this low-cost UAV-system and forage mass. Results indicate that the plant height seems to be a suitable indicator for forage mass. There is a

  7. a Uav Based 3-D Positioning Framework for Detecting Locations of Buried Persons in Collapsed Disaster Area

    Science.gov (United States)

    Moon, H.; Kim, C.; Lee, W.

    2016-06-01

    Regarding spatial location positioning, indoor location positioning theories based on wireless communication techniques such as Wi-Fi, beacon, UWB and Bluetooth has widely been developing across the world. These techniques are mainly focusing on spatial location detection of customers using fixed wireless APs and unique Tags in the indoor environment. Besides, since existing detection equipment and techniques using ultrasound or sound etc. to detect buried persons and identify survival status for them cause 2nd damages on the collapsed debris for rescuers. In addition, it might take time to check the buried persons. However, the collapsed disaster sites should consider both outdoor and indoor environments because empty spaces under collapsed debris exists. In order to detect buried persons from the empty spaces, we should collect wireless signals with Wi-Fi from their mobile phone. Basically, the Wi-Fi signal measure 2-D location. However, since the buried persons have Z value with burial depth, we also should collect barometer sensor data from their mobile phones in order to measure Z values according to weather conditions. Specially, for quick accessibility to the disaster area, a drone (UAV; Unmanned Arial Vehicle) system, which is equipped with a wireless detection module, was introduced. Using these framework, this study aims to provide the rescuers with effective rescue information by calculating 3-D location for buried persons based on the wireless and barometer sensor fusion.

  8. A UAV BASED 3-D POSITIONING FRAMEWORK FOR DETECTING LOCATIONS OF BURIED PERSONS IN COLLAPSED DISASTER AREA

    Directory of Open Access Journals (Sweden)

    H. Moon

    2016-06-01

    Full Text Available Regarding spatial location positioning, indoor location positioning theories based on wireless communication techniques such as Wi-Fi, beacon, UWB and Bluetooth has widely been developing across the world. These techniques are mainly focusing on spatial location detection of customers using fixed wireless APs and unique Tags in the indoor environment. Besides, since existing detection equipment and techniques using ultrasound or sound etc. to detect buried persons and identify survival status for them cause 2nd damages on the collapsed debris for rescuers. In addition, it might take time to check the buried persons. However, the collapsed disaster sites should consider both outdoor and indoor environments because empty spaces under collapsed debris exists. In order to detect buried persons from the empty spaces, we should collect wireless signals with Wi-Fi from their mobile phone. Basically, the Wi-Fi signal measure 2-D location. However, since the buried persons have Z value with burial depth, we also should collect barometer sensor data from their mobile phones in order to measure Z values according to weather conditions. Specially, for quick accessibility to the disaster area, a drone (UAV; Unmanned Arial Vehicle system, which is equipped with a wireless detection module, was introduced. Using these framework, this study aims to provide the rescuers with effective rescue information by calculating 3-D location for buried persons based on the wireless and barometer sensor fusion.

  9. A Novel Methodology for Improving Plant Pest Surveillance in Vineyards and Crops Using UAV-Based Hyperspectral and Spatial Data

    Directory of Open Access Journals (Sweden)

    Fernando Vanegas

    2018-01-01

    Full Text Available Recent advances in remote sensed imagery and geospatial image processing using unmanned aerial vehicles (UAVs have enabled the rapid and ongoing development of monitoring tools for crop management and the detection/surveillance of insect pests. This paper describes a (UAV remote sensing-based methodology to increase the efficiency of existing surveillance practices (human inspectors and insect traps for detecting pest infestations (e.g., grape phylloxera in vineyards. The methodology uses a UAV integrated with advanced digital hyperspectral, multispectral, and RGB sensors. We implemented the methodology for the development of a predictive model for phylloxera detection. In this method, we explore the combination of airborne RGB, multispectral, and hyperspectral imagery with ground-based data at two separate time periods and under different levels of phylloxera infestation. We describe the technology used—the sensors, the UAV, and the flight operations—the processing workflow of the datasets from each imagery type, and the methods for combining multiple airborne with ground-based datasets. Finally, we present relevant results of correlation between the different processed datasets. The objective of this research is to develop a novel methodology for collecting, processing, analising and integrating multispectral, hyperspectral, ground and spatial data to remote sense different variables in different applications, such as, in this case, plant pest surveillance. The development of such methodology would provide researchers, agronomists, and UAV practitioners reliable data collection protocols and methods to achieve faster processing techniques and integrate multiple sources of data in diverse remote sensing applications.

  10. A Novel Methodology for Improving Plant Pest Surveillance in Vineyards and Crops Using UAV-Based Hyperspectral and Spatial Data.

    Science.gov (United States)

    Vanegas, Fernando; Bratanov, Dmitry; Powell, Kevin; Weiss, John; Gonzalez, Felipe

    2018-01-17

    Recent advances in remote sensed imagery and geospatial image processing using unmanned aerial vehicles (UAVs) have enabled the rapid and ongoing development of monitoring tools for crop management and the detection/surveillance of insect pests. This paper describes a (UAV) remote sensing-based methodology to increase the efficiency of existing surveillance practices (human inspectors and insect traps) for detecting pest infestations (e.g., grape phylloxera in vineyards). The methodology uses a UAV integrated with advanced digital hyperspectral, multispectral, and RGB sensors. We implemented the methodology for the development of a predictive model for phylloxera detection. In this method, we explore the combination of airborne RGB, multispectral, and hyperspectral imagery with ground-based data at two separate time periods and under different levels of phylloxera infestation. We describe the technology used-the sensors, the UAV, and the flight operations-the processing workflow of the datasets from each imagery type, and the methods for combining multiple airborne with ground-based datasets. Finally, we present relevant results of correlation between the different processed datasets. The objective of this research is to develop a novel methodology for collecting, processing, analising and integrating multispectral, hyperspectral, ground and spatial data to remote sense different variables in different applications, such as, in this case, plant pest surveillance. The development of such methodology would provide researchers, agronomists, and UAV practitioners reliable data collection protocols and methods to achieve faster processing techniques and integrate multiple sources of data in diverse remote sensing applications.

  11. A Novel Methodology for Improving Plant Pest Surveillance in Vineyards and Crops Using UAV-Based Hyperspectral and Spatial Data

    Science.gov (United States)

    Vanegas, Fernando; Weiss, John; Gonzalez, Felipe

    2018-01-01

    Recent advances in remote sensed imagery and geospatial image processing using unmanned aerial vehicles (UAVs) have enabled the rapid and ongoing development of monitoring tools for crop management and the detection/surveillance of insect pests. This paper describes a (UAV) remote sensing-based methodology to increase the efficiency of existing surveillance practices (human inspectors and insect traps) for detecting pest infestations (e.g., grape phylloxera in vineyards). The methodology uses a UAV integrated with advanced digital hyperspectral, multispectral, and RGB sensors. We implemented the methodology for the development of a predictive model for phylloxera detection. In this method, we explore the combination of airborne RGB, multispectral, and hyperspectral imagery with ground-based data at two separate time periods and under different levels of phylloxera infestation. We describe the technology used—the sensors, the UAV, and the flight operations—the processing workflow of the datasets from each imagery type, and the methods for combining multiple airborne with ground-based datasets. Finally, we present relevant results of correlation between the different processed datasets. The objective of this research is to develop a novel methodology for collecting, processing, analysing and integrating multispectral, hyperspectral, ground and spatial data to remote sense different variables in different applications, such as, in this case, plant pest surveillance. The development of such methodology would provide researchers, agronomists, and UAV practitioners reliable data collection protocols and methods to achieve faster processing techniques and integrate multiple sources of data in diverse remote sensing applications. PMID:29342101

  12. Simulation and analysis of plasmonic sensor in NIR with fluoride glass and graphene layer

    Science.gov (United States)

    Pandey, Ankit Kumar; Sharma, Anuj K.

    2018-02-01

    A calcium fluoride (CaF2) prism based plasmonic biosensor with graphene layer is proposed in near infrared region (NIR) of operation. The stacking of multilayer graphene is considered with dielectric interlayer sandwiched between two graphene layers. Excellent optical properties of CaF2 glass and enhanced field at the graphene-analyte interface are intended to be exploited for proposed sensor structure in NIR spectral region. Performance parameters in terms of field enhancement at interface and figure of merit (FOM) are analyzed and compared with those of conventional SPR based sensor. It is demonstrated that the same sensor probe can also be used for gas sensing with nearly 3.5-4 times enhancement in FOM, compared with conventional sensor. The results show that CaF2 based SPR sensor provides much better sensitivity than that based on other glasses.

  13. Design and integration of vision based sensors for unmanned aerial vehicles navigation and guidance

    Science.gov (United States)

    Sabatini, Roberto; Bartel, Celia; Kaharkar, Anish; Shaid, Tesheen

    2012-04-01

    In this paper we present a novel Navigation and Guidance System (NGS) for Unmanned Aerial Vehicles (UAVs) based on Vision Based Navigation (VBN) and other avionics sensors. The main objective of our research is to design a lowcost and low-weight/volume NGS capable of providing the required level of performance in all flight phases of modern small- to medium-size UAVs, with a special focus on automated precision approach and landing, where VBN techniques can be fully exploited in a multisensory integrated architecture. Various existing techniques for VBN are compared and the Appearance-based Navigation (ABN) approach is selected for implementation. Feature extraction and optical flow techniques are employed to estimate flight parameters such as roll angle, pitch angle, deviation from the runway and body rates. Additionally, we address the possible synergies between VBN, Global Navigation Satellite System (GNSS) and MEMS-IMU (Micro-Electromechanical System Inertial Measurement Unit) sensors and also the use of Aircraft Dynamics Models (ADMs) to provide additional information suitable to compensate for the shortcomings of VBN sensors in high-dynamics attitude determination tasks. An Extended Kalman Filter (EKF) is developed to fuse the information provided by the different sensors and to provide estimates of position, velocity and attitude of the platform in real-time. Two different integrated navigation system architectures are implemented. The first uses VBN at 20 Hz and GPS at 1 Hz to augment the MEMS-IMU running at 100 Hz. The second mode also includes the ADM (computations performed at 100 Hz) to provide augmentation of the attitude channel. Simulation of these two modes is performed in a significant portion of the Aerosonde UAV operational flight envelope and performing a variety of representative manoeuvres (i.e., straight climb, level turning, turning descent and climb, straight descent, etc.). Simulation of the first integrated navigation system architecture

  14. Using UAV-Based Photogrammetry and Hyperspectral Imaging for Mapping Bark Beetle Damage at Tree-Level

    Directory of Open Access Journals (Sweden)

    Roope Näsi

    2015-11-01

    Full Text Available Low-cost, miniaturized hyperspectral imaging technology is becoming available for small unmanned aerial vehicle (UAV platforms. This technology can be efficient in carrying out small-area inspections of anomalous reflectance characteristics of trees at a very high level of detail. Increased frequency and intensity of insect induced forest disturbance has established a new demand for effective methods suitable in mapping and monitoring tasks. In this investigation, a novel miniaturized hyperspectral frame imaging sensor operating in the wavelength range of 500–900 nm was used to identify mature Norway spruce (Picea abies L. Karst. trees suffering from infestation, representing a different outbreak phase, by the European spruce bark beetle (Ips typographus L.. We developed a new processing method for analyzing spectral characteristic for high spatial resolution photogrammetric and hyperspectral images in forested environments, as well as for identifying individual anomalous trees. The dense point clouds, measured using image matching, enabled detection of single trees with an accuracy of 74.7%. We classified the trees into classes of healthy, infested and dead, and the results were promising. The best results for the overall accuracy were 76% (Cohen’s kappa 0.60, when using three color classes (healthy, infested, dead. For two color classes (healthy, dead, the best overall accuracy was 90% (kappa 0.80. The survey methodology based on high-resolution hyperspectral imaging will be of a high practical value for forest health management, indicating a status of bark beetle outbreak in time.

  15. Simulation and Experimental Investigations on the Strain Measurement of the Uniform Strength Beam Using a FBG sensor

    International Nuclear Information System (INIS)

    Tu Yumeng; Gong Huaping; Chen Jixuan; Jin Yongxing

    2011-01-01

    The model of force analysis on a uniform strength beam is built by the general finite element program (ANSYS software). The flexivity profile produced by uniform strength beam with different forces is simulated by ANSYS software. In experiment, a fiber Bragg grating sensor is fixed on the uniform strength beam with modified acrylate. The flexivity and strain are varied by changing the load on the end of the beam. The strain of the uniform strength beam is measured with FBG when applied force is varied from 2.45N to14.7N with a step of 2.45N. Both the simulated and experimental results show that, the strain induced by the uniform strength beam is linear with the load force. The sensitivity is 18.32με/N for experimental measurement, and 19.72με/N for simulation. The experimental results are consistent with the simulation results, with the maximum measurement error of strain being 7.4%. It indicates that, the FBG sensor fixed with modified acrylate is proved to be effectively and reliably in the applications of civil engineering.

  16. Modeling and simulation of adaptive multimodal optical sensors for target tracking in the visible to near infrared

    Science.gov (United States)

    Presnar, Michael D.

    This work investigates an integrated aerial remote sensor design approach to address moving target detection and tracking problems within highly cluttered, dynamic ground-based scenes. Sophisticated simulation methodologies and scene phenomenology validations have resulted in advancements in artificial multimodal truth video synthesis. Complex modeling of novel micro-opto-electro-mechanical systems (MOEMS) devices, optical systems, and detector arrays has resulted in a proof of concept for a state-of-the-art imaging spectropolarimeter sensor model that does not suffer from typical multimodal image registration problems. Test methodology developed for this work provides the ability to quantify performance of a target tracking application with varying ground scenery, flight characteristics, or sensor specifications. The culmination of this research is an end-to-end simulated demonstration of multimodal aerial remote sensing and target tracking. Deeply hidden target recognition is shown to be enhanced through the fusing of panchromatic, hyperspectral, and polarimetric image modalities. The Digital Imaging and Remote Sensing Image Generation model was leveraged to synthesize truth spectropolarimetric sensor-reaching radiance image cubes comprised of coregistered Stokes vector bands in the visible to near-infrared. An intricate synthetic urban scene containing numerous moving vehicular targets was imaged from a virtual sensor aboard an aerial platform encircling a stare point. An adaptive sensor model was designed with a superpixel array of MOEMS devices fabricated atop a division of focal plane detector. Degree of linear polarization (DoLP) imagery is acquired by combining three adjacent micropolarizer outputs within each 2x2 superpixel whose respective transmissions vary with wavelength, relative angle of polarization, and wire-grid spacing. A novel micromirror within each superpixel adaptively relays light between a panchromatic imaging channel and a hyperspectral

  17. Design, experiments and simulation of voltage transformers on the basis of a differential input D-dot sensor.

    Science.gov (United States)

    Wang, Jingang; Gao, Can; Yang, Jie

    2014-07-17

    Currently available traditional electromagnetic voltage sensors fail to meet the measurement requirements of the smart grid, because of low accuracy in the static and dynamic ranges and the occurrence of ferromagnetic resonance attributed to overvoltage and output short circuit. This work develops a new non-contact high-bandwidth voltage measurement system for power equipment. This system aims at the miniaturization and non-contact measurement of the smart grid. After traditional D-dot voltage probe analysis, an improved method is proposed. For the sensor to work in a self-integrating pattern, the differential input pattern is adopted for circuit design, and grounding is removed. To prove the structure design, circuit component parameters, and insulation characteristics, Ansoft Maxwell software is used for the simulation. Moreover, the new probe was tested on a 10 kV high-voltage test platform for steady-state error and transient behavior. Experimental results ascertain that the root mean square values of measured voltage are precise and that the phase error is small. The D-dot voltage sensor not only meets the requirement of high accuracy but also exhibits satisfactory transient response. This sensor can meet the intelligence, miniaturization, and convenience requirements of the smart grid.

  18. Design, Experiments and Simulation of Voltage Transformers on the Basis of a Differential Input D-dot Sensor

    Directory of Open Access Journals (Sweden)

    Jingang Wang

    2014-07-01

    Full Text Available Currently available traditional electromagnetic voltage sensors fail to meet the measurement requirements of the smart grid, because of low accuracy in the static and dynamic ranges and the occurrence of ferromagnetic resonance attributed to overvoltage and output short circuit. This work develops a new non-contact high-bandwidth voltage measurement system for power equipment. This system aims at the miniaturization and non-contact measurement of the smart grid. After traditional D-dot voltage probe analysis, an improved method is proposed. For the sensor to work in a self-integrating pattern, the differential input pattern is adopted for circuit design, and grounding is removed. To prove the structure design, circuit component parameters, and insulation characteristics, Ansoft Maxwell software is used for the simulation. Moreover, the new probe was tested on a 10 kV high-voltage test platform for steady-state error and transient behavior. Experimental results ascertain that the root mean square values of measured voltage are precise and that the phase error is small. The D-dot voltage sensor not only meets the requirement of high accuracy but also exhibits satisfactory transient response. This sensor can meet the intelligence, miniaturization, and convenience requirements of the smart grid.

  19. FEM Simulation of Influence of Protective Encapsulation on MEMS Pressure Sensor

    DEFF Research Database (Denmark)

    Yao, Qingshan; Janting, Jakob; Branebjerg, Jens

    2003-01-01

    The objective of the work is to evaluate the feasibility of packaging a MEMS silicon pressure sensor by using either a polymer encapsulation or a combination of a polymer encapsulation and a metallic protection Membrane (fig. 1). The potential application of the protected sensor is for harsh...... compared to the conventionally exposed sensor. 2) Stress concentration calculations are performed to investigate if the encapsulation could lead to increased stress concentration in the silicon structure. The reliability of the adhesion of the metallic encapsulating membrane is assessed by investigating...... whether the metallic membrane / coating will peel off when applying the maximum pressure, which is 4000 bar leading to high shear stress between the metallic membrane and the polymer encapsulation material.3) Thermal calculations are made to evaluate the influence of the environment on the packaged sensor...

  20. Robust Modal Filtering and Control of the X-56A Model with Simulated Fiber Optic Sensor Failures

    Science.gov (United States)

    Suh, Peter M.; Chin, Alexander W.; Mavris, Dimitri N.

    2016-01-01

    The X-56A aircraft is a remotely-piloted aircraft with flutter modes intentionally designed into the flight envelope. The X-56A program must demonstrate flight control while suppressing all unstable modes. A previous X-56A model study demonstrated a distributed-sensing-based active shape and active flutter suppression controller. The controller relies on an estimator which is sensitive to bias. This estimator is improved herein, and a real-time robust estimator is derived and demonstrated on 1530 fiber optic sensors. It is shown in simulation that the estimator can simultaneously reject 230 worst-case fiber optic sensor failures automatically. These sensor failures include locations with high leverage (or importance). To reduce the impact of leverage outliers, concentration based on a Mahalanobis trim criterion is introduced. A redescending M-estimator with Tukey bisquare weights is used to improve location and dispersion estimates within each concentration step in the presence of asymmetry (or leverage). A dynamic simulation is used to compare the concentrated robust estimator to a state-of-the-art real-time robust multivariate estimator. The estimators support a previously-derived mu-optimal shape controller. It is found that during the failure scenario, the concentrated modal estimator keeps the system stable.

  1. Simulation and Analysis of Reciever-Receiver Time Synchronization in Wireless Sensor Networks

    OpenAIRE

    Devendrasingh Thakore; Shashank Bholane

    2012-01-01

    Wireless sensor networks were initially deployed for military applications. Gradually researchers found them to be very useful in applications like weather monitoring, target tracking, agriculture, industrial applications, and recently smart homes and kindergartens. All the WSN applications need partial or full time synchronization. Applications like acoustic ranging, target tracking or monitoring need a common notion of time. Every data is time stamped sensor nodes local clock. Two main appr...

  2. Energy- and information-managed wireless sensor networks: modelling and simulation

    OpenAIRE

    Merrett, Geoff V.

    2008-01-01

    Wireless Sensor Networks (WSNs) allow the remote and distributed monitoring of parameters in their deployed environment. WSNs are receiving increasing research interest, due to their ability to enable a wide range of applications, and their potential to have a major impact on ubiquitous computing. Many research challenges are encountered in retaining a useful network lifetime under constrains imposed by the limited energy reserves that are inherent in the small, locally-powered sensor n...

  3. Predicting grain yield in rice using multi-temporal vegetation indices from UAV-based multispectral and digital imagery

    Science.gov (United States)

    Zhou, X.; Zheng, H. B.; Xu, X. Q.; He, J. Y.; Ge, X. K.; Yao, X.; Cheng, T.; Zhu, Y.; Cao, W. X.; Tian, Y. C.

    2017-08-01

    Timely and non-destructive assessment of crop yield is an essential part of agricultural remote sensing (RS). The development of unmanned aerial vehicles (UAVs) has provided a novel approach for RS, and makes it possible to acquire high spatio-temporal resolution imagery on a regional scale. In this study, the rice grain yield was predicted with single stage vegetation indices (VIs) and multi-temporal VIs derived from the multispectral (MS) and digital images. The results showed that the booting stage was identified as the optimal stage for grain yield prediction with VIs at a single stage for both digital image and MS image. And corresponding optimal color index was VARI with R2 value of 0.71 (Log relationship). While the optimal vegetation index NDVI[800,720] based on MS images showed a linear relationship with the grain yield and gained a higher R2 value (0.75) than color index did. The multi-temporal VIs showed a higher correlation with grain yield than the single stage VIs did. And the VIs at two random growth stage with the multiple linear regression function [MLR(VI)] performed best. The highest correlation coefficient were 0.76 with MLR(NDVI[800,720]) at the booting and heading stages (for the MS image) and 0.73 with MLR(VARI) at the jointing and booting stages (for the digital image). In addition, the VIs that showed a high correlation with LAI performed well for yield prediction, and the VIs composed of red edge band (720 nm) and near infrared band (800 nm) were found to be more effective in predicting yield and LAI at high level. In conclusion, this study has demonstrated that both MS and digital sensors mounted on the UAV are reliable platforms for rice growth and grain yield estimation, and determined the best period and optimal VIs for rice grain yield prediction.

  4. Modeling and Testing of Growth Status for Chinese Cabbage and White Radish with UAV-Based RGB Imagery

    Directory of Open Access Journals (Sweden)

    Dong-Wook Kim

    2018-04-01

    Full Text Available Conventional crop-monitoring methods are time-consuming and labor-intensive, necessitating new techniques to provide faster measurements and higher sampling intensity. This study reports on mathematical modeling and testing of growth status for Chinese cabbage and white radish using unmanned aerial vehicle-red, green and blue (UAV-RGB imagery for measurement of their biophysical properties. Chinese cabbage seedlings and white radish seeds were planted at 7–10-day intervals to provide a wide range of growth rates. Remotely sensed digital imagery data were collected for test fields at approximately one-week intervals using a UAV platform equipped with an RGB digital camera flying at 2 m/s at 20 m above ground. Radiometric calibrations for the RGB band sensors were performed on every UAV flight using standard calibration panels to minimize the effect of ever-changing light conditions on the RGB images. Vegetation fractions (VFs of crops in each region of interest from the mosaicked ortho-images were calculated as the ratio of pixels classified as crops segmented using the Otsu threshold method and a vegetation index of excess green (ExG. Plant heights (PHs were estimated using the structure from motion (SfM algorithm to create 3D surface models from crop canopy data. Multiple linear regression equations consisting of three predictor variables (VF, PH, and VF × PH and four different response variables (fresh weight, leaf length, leaf width, and leaf count provided good fits with coefficients of determination (R2 ranging from 0.66 to 0.90. The validation results using a dataset of crop growth obtained in a different year also showed strong linear relationships (R2 > 0.76 between the developed regression models and standard methods, confirming that the models make it possible to use UAV-RGB images for quantifying spatial and temporal variability in biophysical properties of Chinese cabbage and white radish over the growing season.

  5. QUALITY ASSESSMENT OF COMBINED IMU/GNSS DATA FOR DIRECT GEOREFERENCING IN THE CONTEXT OF UAV-BASED MAPPING

    Directory of Open Access Journals (Sweden)

    C. Stöcker

    2017-08-01

    Full Text Available Within the past years, the development of high-quality Inertial Measurement Units (IMU and GNSS technology and dedicated RTK (Real Time Kinematic and PPK (Post-Processing Kinematic solutions for UAVs promise accurate measurements of the exterior orientation (EO parameters which allow to georeference the images. Whereas the positive impact of known precise GNSS coordinates of camera positions is already well studied, the influence of the angular observations have not been studied in depth so far. Challenges include accuracies of GNSS/IMU observations, excessive angular motion and time synchronization problems during the flight. Thus, this study assesses the final geometric accuracy using direct georeferencing with high-quality post-processed IMU/GNSS and PPK corrections. A comparison of different data processing scenarios including indirect georeferencing, integrated solutions as well as direct georeferencing provides guidance on the workability of UAV mapping approaches that require a high level of positional accuracy. In the current research the results show, that the use of the post-processed APX-15 GNSS and IMU data was particularly beneficial to enhance the image orientation quality. Horizontal accuracies within the pixel level (2.8 cm could be achieved. However, it was also shown, that the angular EO parameters are still too inaccurate to be assigned with a high weight during the image orientation process. Furthermore, detailed investigations of the EO parameters unveil that systematic sensor misalignments and offsets of the image block can be reduced by the introduction of four GCPs. In this regard, the use of PPK corrections reduces the time consuming field work to measure high quantities of GCPs and makes large-scale UAV mapping a more feasible solution for practitioners that require high geometric accuracies.

  6. Quality Assessment of Combined Imu/gnss Data for Direct Georeferencing in the Context of Uav-Based Mapping

    Science.gov (United States)

    Stöcker, C.; Nex, F.; Koeva, M.; Gerke, M.

    2017-08-01

    Within the past years, the development of high-quality Inertial Measurement Units (IMU) and GNSS technology and dedicated RTK (Real Time Kinematic) and PPK (Post-Processing Kinematic) solutions for UAVs promise accurate measurements of the exterior orientation (EO) parameters which allow to georeference the images. Whereas the positive impact of known precise GNSS coordinates of camera positions is already well studied, the influence of the angular observations have not been studied in depth so far. Challenges include accuracies of GNSS/IMU observations, excessive angular motion and time synchronization problems during the flight. Thus, this study assesses the final geometric accuracy using direct georeferencing with high-quality post-processed IMU/GNSS and PPK corrections. A comparison of different data processing scenarios including indirect georeferencing, integrated solutions as well as direct georeferencing provides guidance on the workability of UAV mapping approaches that require a high level of positional accuracy. In the current research the results show, that the use of the post-processed APX-15 GNSS and IMU data was particularly beneficial to enhance the image orientation quality. Horizontal accuracies within the pixel level (2.8 cm) could be achieved. However, it was also shown, that the angular EO parameters are still too inaccurate to be assigned with a high weight during the image orientation process. Furthermore, detailed investigations of the EO parameters unveil that systematic sensor misalignments and offsets of the image block can be reduced by the introduction of four GCPs. In this regard, the use of PPK corrections reduces the time consuming field work to measure high quantities of GCPs and makes large-scale UAV mapping a more feasible solution for practitioners that require high geometric accuracies.

  7. Optimal multi-agent path planning for fast inverse modeling in UAV-based flood sensing applications

    KAUST Repository

    Abdelkader, Mohamed

    2014-05-01

    Floods are the most common natural disasters, causing thousands of casualties every year in the world. In particular, flash flood events are particularly deadly because of the short timescales on which they occur. Unmanned air vehicles equipped with mobile microsensors could be capable of sensing flash floods in real time, saving lives and greatly improving the efficiency of the emergency response. However, of the main issues arising with sensing floods is the difficulty of planning the path of the sensing agents in advance so as to obtain meaningful data as fast as possible. In this particle, we present a fast numerical scheme to quickly compute the trajectories of a set of UAVs in order to maximize the accuracy of model parameter estimation over a time horizon. Simulation results are presented, a preliminary testbed is briefly described, and future research directions and problems are discussed. © 2014 IEEE.

  8. On a Novel Simulation Framework and Scheduling Model Integrating Coverage Mechanisms for Sensor Networks and Handling Concurrency

    Science.gov (United States)

    Filippou, A.; Karras, D. A.; Papazoglou, P. M.; Papademetriou, R. C.

    Coverage is one of the fundamental metrics used to quantify the quality of service (QoS) of sensor networks. In general, we use this term to measure the ability of the network to observe and react to the phenomena taking place in the area of interest of the network. In addition, coverage is associated with connectivity and energy consumption, both important aspects in the design process of a Wireless Sensor Network (WSN). On the other hand, simulating a WSN involves taking into account different software and hardware aspects. In this paper we attempt to present a simulation framework suitable for integrating coverage mechanisms in WSN emulation using a layered architecture and a fitting scheduling model. The suggested model is derived after a critical overview and presentation of the coverage strategies as well as the simulation approaches for WSN developed so far. The main advantage of the proposed framework is its capability to handle concurrent events occurring at WSN deployment and operation through the suitable layered scheduler integrated.

  9. Simulation of Meteosat Third Generation-Lightning Imager through tropical rainfall measuring mission: Lightning Imaging Sensor data

    Science.gov (United States)

    Biron, Daniele; De Leonibus, Luigi; Laquale, Paolo; Labate, Demetrio; Zauli, Francesco; Melfi, Davide

    2008-08-01

    The Centro Nazionale di Meteorologia e Climatologia Aeronautica recently hosted a fellowship sponsored by Galileo Avionica, with the intent to study and perform a simulation of Meteosat Third Generation - Lightning Imager (MTG-LI) sensor behavior through Tropical Rainfall Measuring Mission - Lightning Imaging Sensor data (TRMM-LIS). For the next generation of earth observation geostationary satellite, major operating agencies are planning to insert an optical imaging mission, that continuously observes lightning pulses in the atmosphere; EUMETSAT has decided in recent years that one of the three candidate mission to be flown on MTG is LI, a Lightning Imager. MTG-LI mission has no Meteosat Second Generation heritage, but users need to evaluate the possible real time data output of the instrument to agree in inserting it on MTG payload. Authors took the expected LI design from MTG Mission Requirement Document, and reprocess real lightning dataset, acquired from space by TRMM-LIS instrument, to produce a simulated MTG-LI lightning dataset. The simulation is performed in several run, varying Minimum Detectable Energy, taking into account processing steps from event detection to final lightning information. A definition of the specific meteorological requirements is given from the potential use in meteorology of lightning final information for convection estimation and numerical cloud modeling. Study results show the range of instrument requirements relaxation which lead to minimal reduction in the final lightning information.

  10. New poly(N,N-dimethylaminoethyl methacrylate)/polyvinyl alcohol copolymer coated QCM sensor for interaction with CWA simulants.

    Science.gov (United States)

    Zhang, Zhi; Fan, Jun; Yu, Jianmei; Zheng, Shengrun; Chen, Wenjing; Li, Heguo; Wang, Zhijun; Zhang, Weiguang

    2012-02-01

    A series of copolymers, namely, poly (N, N-dimethylaminoethyl methacrylate)/polyvinyl alcohol (PDMAEMA/PVA), have been obtained through emulsion polymerization. Then, a synthetic copolymer (PDMAEMA/PVA)-coated quartz crystal microbalance sensor (PC-QCM) has been developed to apply in evaluating the interactions between the copolymers and three chemical warfare agent (CWA) simulants, such as diethyl chlorophosphate (DCP), 2,2'-dichlorodiethyl ether (DCE), and dimethyl methylphosphonate (DMMP). The results from the QCM measurements indicate that the PDMAEMA/PVA copolymers not only directly degradate sarin simulants (DCP and DMMP), but also show obvious absorption in mustard gas simulant (DCE). In addition, the mass of degraded DCP by the copolymer is calculated on the basis of resonance frequency shifts (Δf) of quartz crystal in the QCM sensor, which may be applied to quantitatively evaluate the reactivity of PDMAEMA/PVA copolymers. Furthermore, the fluorescence of PDMAEMA/PVA copolymers in DMSO solution gradually quenched with the addition of DCP solution, which can be explained that the reactions take place between DCP and reactive groups of PDMAEMA/PVA copolymers. Thus, this PDMAEMA/PVA membrane may be a good candidate for the application in chemical warfare protective materials, and this new PC-QCM technique shows potential application in the rapid, real-time, and sensitive detection of the chemical warfare agents and hazardous chemicals.

  11. FEASIBILITY COMPARISON OF AIRBORNE LASER SCANNING DATA AND 3D-POINT CLOUDS FORMED FROM UNMANNED AERIAL VEHICLE (UAV-BASED IMAGERY USED FOR 3D PROJECTING

    Directory of Open Access Journals (Sweden)

    I. I. Rilskiy

    2017-01-01

    Full Text Available New, innovative methods of aerial surveys have changed the approaches to information provision of projecting dramatically for the last 15 years. Nowadays there are at least two methods that claim to be the most efficient way for collecting geospatial data intended for projecting – the airborne laser scanning (LIDAR data and photogrammetrically processed unmanned aerial vehicle (UAV-based aerial imagery, forming 3D point clouds. But these materials are not identical to each other neither in precision, nor in completeness.Airborne laser scanning (LIDAR is normally being performed using manned aircrafts. LIDAR data are very precise, they allow us to achieve data about relief even overgrown with vegetation, or to collect laser reflections from wires, metal constructions and poles. UAV surveys are normally being performed using frame digital cameras (lightweight, full-frame, or mid-size. These cameras form images that are being processed using 3D photogrammetric software in automatic mode that allows one to generate 3D point cloud, which is used for building digital elevation models, surfaces, orthomosaics, etc.All these materials are traditionally being used for making maps and GIS data. LIDAR data have been popular in design work. Also there have been some attempts to use for the same purpose 3D-point clouds, formed by photogrammetric software from images acquired from UAVs.After comparison of the datasets from these two different types of surveying (surveys were made simultaneously on the same territory, it became possible to define some specific, typical for LIDAR or imagery-based 3D data. It can be mentioned that imagery-based 3D data (3D point clouds, formed in automatic mode using photogrammetry, are much worse than LIDAR data – both in terms of precision and completeness.The article highlights these differences and makes attempts at explaining the origin of these differences. 

  12. Spectrum correction algorithm for detectors in airborne radioactivity monitoring equipment NH-UAV based on a ratio processing method

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Ye [Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Tang, Xiao-Bin, E-mail: tangxiaobin@nuaa.edu.cn [Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Jiangsu Key Laboratory of Nuclear Energy Equipment Materials Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Wang, Peng; Meng, Jia; Huang, Xi; Wen, Liang-Sheng [Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Chen, Da [Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Jiangsu Key Laboratory of Nuclear Energy Equipment Materials Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

    2015-10-11

    The unmanned aerial vehicle (UAV) radiation monitoring method plays an important role in nuclear accidents emergency. In this research, a spectrum correction algorithm about the UAV airborne radioactivity monitoring equipment NH-UAV was studied to measure the radioactive nuclides within a small area in real time and in a fixed place. The simulation spectra of the high-purity germanium (HPGe) detector and the lanthanum bromide (LaBr{sub 3}) detector in the equipment were obtained using the Monte Carlo technique. Spectrum correction coefficients were calculated after performing ratio processing techniques about the net peak areas between the double detectors on the detection spectrum of the LaBr{sub 3} detector according to the accuracy of the detection spectrum of the HPGe detector. The relationship between the spectrum correction coefficient and the size of the source term was also investigated. A good linear relation exists between the spectrum correction coefficient and the corresponding energy (R{sup 2}=0.9765). The maximum relative deviation from the real condition reduced from 1.65 to 0.035. The spectrum correction method was verified as feasible. - Highlights: • An airborne radioactivity monitoring equipment NH-UAV was developed to measure radionuclide after a nuclear accident. • A spectrum correction algorithm was proposed to obtain precise information on the detected radioactivity within a small area. • The spectrum correction method was verified as feasible. • The corresponding spectrum correction coefficients increase first and then stay constant.

  13. Simulation and Analysis of Strain Sensitivity of CNT-Based Strain Sensors

    Science.gov (United States)

    Sapra, Gaurav; Vig, Renu; Sharma, Manu

    2016-10-01

    Carbon nanotubes (CNT) is turning out to be a replacement to all the existing traditional sensors due to their high gauge factor, multidirectional sensing capability, high flexibility, low mass density, high dynamic range and high sensitivity to strains at nano and macro- scales. The strain sensitivity of CNT-based strain sensors depends on number of parameters; quality and quantity of CNT used, type of polymer used, deposition and dispersion technique adopted and also on environmental conditions. Due to all these parameters, the piezoresistive behavior of CNT is diversified and it needs to be explored. This paper theoretically analyses the strain sensitivity of CNT-based strain sensors. The strain sensitivity response of CNT strain sensor is a result of change in total resistance of CNT network with respect to applied strain. The total resistance of CNT network consists of intrinsic resistance and inter-tube resistance. It has been found that the change in intrinsic resistance under strain is due to the variation of bandgap of individual, which depends on the chirality of the tube and it varies exponentially with strain. The inter-tube resistance of CNT network changes nonlinearly due to change in distance between neighboring CNTs with respect to applied strain. As the distance d between CNTs increases due to applied strain, tunneling resistance Rtunnel increases nonlinearly in exponential manner. When the concentration of CNTs in composite is close to percolation threshold, then the change of inter-tube resistances is more dominant than intrinsic resistance. At percolation threshold, the total resistance of CNT networks changes nonlinearly and this effect of nonlinearity is due to tunneling effect. The strain sensitivity of CNT-based strain sensors also varies nonlinearly with the change in temperature. For the change of temperature from -20∘C to 50∘C, there is more than 100% change in strain sensitivity of CNT/polymer composite strain sensor. This change is

  14. A Model-Based Approach for Bridging Virtual and Physical Sensor Nodes in a Hybrid Simulation Framework

    Directory of Open Access Journals (Sweden)

    Mohammad Mozumdar

    2014-06-01

    Full Text Available The Model Based Design (MBD approach is a popular trend to speed up application development of embedded systems, which uses high-level abstractions to capture functional requirements in an executable manner, and which automates implementation code generation. Wireless Sensor Networks (WSNs are an emerging very promising application area for embedded systems. However, there is a lack of tools in this area, which would allow an application developer to model a WSN application by using high level abstractions, simulate it mapped to a multi-node scenario for functional analysis, and finally use the refined model to automatically generate code for different WSN platforms. Motivated by this idea, in this paper we present a hybrid simulation framework that not only follows the MBD approach for WSN application development, but also interconnects a simulated sub-network with a physical sub-network and then allows one to co-simulate them, which is also known as Hardware-In-the-Loop (HIL simulation.

  15. Method for Vibration Response Simulation and Sensor Placement Optimization of a Machine Tool Spindle System with a Bearing Defect

    Science.gov (United States)

    Cao, Hongrui; Niu, Linkai; He, Zhengjia

    2012-01-01

    Bearing defects are one of the most important mechanical sources for vibration and noise generation in machine tool spindles. In this study, an integrated finite element (FE) model is proposed to predict the vibration responses of a spindle bearing system with localized bearing defects and then the sensor placement for better detection of bearing faults is optimized. A nonlinear bearing model is developed based on Jones' bearing theory, while the drawbar, shaft and housing are modeled as Timoshenko's beam. The bearing model is then integrated into the FE model of drawbar/shaft/housing by assembling equations of motion. The Newmark time integration method is used to solve the vibration responses numerically. The FE model of the spindle-bearing system was verified by conducting dynamic tests. Then, the localized bearing defects were modeled and vibration responses generated by the outer ring defect were simulated as an illustration. The optimization scheme of the sensor placement was carried out on the test spindle. The results proved that, the optimal sensor placement depends on the vibration modes under different boundary conditions and the transfer path between the excitation and the response. PMID:23012514

  16. Modelling and Simulation of the Knee Joint with a Depth Sensor Camera for Prosthetics and Movement Rehabilitation

    Science.gov (United States)

    Risto, S.; Kallergi, M.

    2015-09-01

    The purpose of this project was to model and simulate the knee joint. A computer model of the knee joint was first created, which was controlled by Microsoft's Kinect for Windows. Kinect created a depth map of the knee and lower leg motion independent of lighting conditions through an infrared sensor. A combination of open source software such as Blender, Python, Kinect SDK and NI_Mate were implemented for the creation and control of the simulated knee based on movements of a live physical model. A physical size model of the knee and lower leg was also created, the movement of which was controlled remotely by the computer model and Kinect. The real time communication of the model and the robotic knee was achieved through programming in Python and Arduino language. The result of this study showed that Kinect in the modelling of human kinematics and can play a significant role in the development of prosthetics and other assistive technologies.

  17. A Proposed Scalable Design and Simulation of Wireless Sensor Network-Based Long-Distance Water Pipeline Leakage Monitoring System

    Directory of Open Access Journals (Sweden)

    Abdulaziz S. Almazyad

    2014-02-01

    Full Text Available Anomalies such as leakage and bursts in water pipelines have severe consequences for the environment and the economy. To ensure the reliability of water pipelines, they must be monitored effectively. Wireless Sensor Networks (WSNs have emerged as an effective technology for monitoring critical infrastructure such as water, oil and gas pipelines. In this paper, we present a scalable design and simulation of a water pipeline leakage monitoring system using Radio Frequency IDentification (RFID and WSN technology. The proposed design targets long-distance aboveground water pipelines that have special considerations for maintenance, energy consumption and cost. The design is based on deploying a group of mobile wireless sensor nodes inside the pipeline and allowing them to work cooperatively according to a prescheduled order. Under this mechanism, only one node is active at a time, while the other nodes are sleeping. The node whose turn is next wakes up according to one of three wakeup techniques: location-based, time-based and interrupt-driven. In this paper, mathematical models are derived for each technique to estimate the corresponding energy consumption and memory size requirements. The proposed equations are analyzed and the results are validated using simulation.

  18. Agriculture/Hydroaquaoponic Bioscience Sensor - Mobile App with Simulations and Software for Industry and Science Education Curriculum Module

    Directory of Open Access Journals (Sweden)

    Christine M. Yukech

    2015-02-01

    Full Text Available There is a lot of technological buzz over the past few years regarding taking care of lettuce and hydroponic greenhouse plants and fish. We first review and discuss the recent technologies in the field of hydroponics, especially the hydroponic sensor curriculum project. The College of Engineering at The University of Akron developed a sensor that can detect hydrology, ph, electrical conductivity, nutrient levels, and temperature of hydroponic plants and aquaponic systems. The sensor can optimize the healthy monitoring of plants and fish in greenhouses, homes, schools, and universities anywhere in the world. The goal is to provide sustainable monitoring for growing healthy greenhouse foods 24/7. In this paper, we propose a sustainable solution for optimizing plant growth by using computer simulations and smart phone applications for plant growers and fisheries to access data in real-time and provide guidance on how to manage healthy environments for plants, such as "electric conductivity is lower than the standard for the tomato, so please add 5ml of nutrients". The app will be extended to social media connection, which is enabled by the web access features, where the user can network with hydroponic and aquarium user groups to share information (how to grow a lettuce, ask questions (where can I buy seeds, and gaming for virtual fish and plant growing. The app can be used on a computer, a smart phone or a tablet and provides numerous features that currently need many separate apps, especially in emerging areas such as hydroponics and aquaponics. The data visualization component in the app can enhance the analysis of the variables and data collection. Using the app, plant growers can track results and grow better crops. The app also provides hands-on interactive simulations that connect to the national science standards, providing optimal use of nutrients by taking care of greenhouse plants and fish for hydroponics and aquaponics.

  19. Temperature Simulation of Greenhouse with CFD Methods and Optimal Sensor Placement

    OpenAIRE

    Yanzheng Liu; Jing Chen; Yazhou Lv; Xiaojie Li

    2014-01-01

    The accuracy of information monitoring is significant to increase the effect of Greenhouse Environment Control. In this paper, by taking simulation for the temperature field in the greenhouse as an example, the CFD (Computational Fluid Dynamics) simulation model for measuring the microclimate environment of greenhouse with the principle of thermal environment formation was established, and the temperature distributions under the condition of mechanical ventilation was also simulated. The resu...

  20. Simulations, fabrication and characterization of diamond coated Love wave-type SAW sensors

    Czech Academy of Sciences Publication Activity Database

    Talbi, A.; Soltani, A.; Rumeau, A.; Taylor, Andrew; Drbohlavová, L.; Klimša, Ladislav; Kopeček, Jaromír; Fekete, Ladislav; Krečmarová, Marie; Mortet, Vincent

    2015-01-01

    Roč. 212, č. 11 (2015), 2606-2610 ISSN 1862-6300 R&D Projects: GA MŠk LO1409; GA MŠk(CZ) LM2011029; GA ČR GA13-31783S Institutional support: RVO:68378271 Keywords : acoustic sensors * chemical vapor deposition * diamond * nanocrystalline materials * quartz * surface acoustic waves Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.648, year: 2015

  1. Modeling forest defoliation using simulated BRDF and assessing its effect on reflectance and sensor reaching radiance

    Science.gov (United States)

    Rengarajan, Rajagopalan; Schott, John R.

    2016-09-01

    Remote sensing techniques such as change detection are widely used for mapping and monitoring forest cover to detect the declining health and vigor of forests. These techniques rely on the assumption that the biophysical variation in the forest introduces a corresponding variation in its reflectance. The biophysical variations are assessed by foresters, but these assessment techniques are expensive and cannot be performed frequently to identify a specific level of change in the forest, for example, infection due to gypsy moths that results in forest defoliation. Further, the interaction of atmosphere, sensor characteristics, and phenology that are inherent in the remotely sensed images makes it difficult to separate biophysical changes from observational effects. We have addressed these limitations by developing a method to model the spectral reflectance properties of forests with varying degrees of defoliation using the Digital Image and Remote Sensing Image Generation (DIRSIG) tool. This paper discusses the in-canopy radiative approach and the impact of defoliation on the reflectance and radiance observed by sensors such as Landsat. The results indicate that the relative variation in forest reflectance between a non-defoliated and a 30% defoliated deciduous forest can be as high as 10% in the NIR spectral band. A function can be fit to predict the level of defoliation from the relative variation in radiance. The modeling and analysis techniques can be extended to assess the impact of atmospheric factors and sensor characteristics relative to the biophysical changes as well as for assessing other biophysical variables in forests.

  2. Development and simulation of microfluidic Wheatstone bridge for high-precision sensor

    NARCIS (Netherlands)

    Shipulya, N.D.; Konakov, S.A.; Krzhizhanovskaya, V.V.

    2016-01-01

    In this work we present the results of analytical modeling and 3D computer simulation of microfluidic Wheatstone bridge, which is used for high-accuracy measurements and precision instruments. We propose and simulate a new method of a bridge balancing process by changing the microchannel geometry.

  3. Inertial sensor based gait analysis discriminates subjects with and without visual impairment caused by simulated macular degeneration.

    Science.gov (United States)

    Kanzler, Christoph M; Barth, Jens; Klucken, Jochen; Eskofier, Bjoern M

    2016-08-01

    Macular degeneration is the third leading cause of blindness worldwide and the leading cause of blindness in the developing world. The analysis of gait parameters can be used to assess the influence of macular degeneration on gait. This study examines the effect of macular degeneration on gait using inertial sensor based 3D spatio-temporal gait parameters. We acquired gait data from 21 young and healthy subjects during a 40 m obstacle walk. All subjects had to perform the gait trial with and without macular degeneration simulation glasses. The order of starting with or without glasses alternated between each subject in order to test for training effects. Multiple 3D spatio-temporal gait parameters were calculated for the normal vision as well as the impaired vision groups. The parameters trial time, stride time, stride time coefficient of variation (CV), stance time, stance time CV, stride length, cadence, gait velocity and angle at toe off showed statistically significant differences between the two groups. Training effects were visible for the trials which started without vision impairment. Inter-group differences in the gait pattern occurred due to an increased sense of insecurity related with the loss of visual acuity from the simulation glasses. In summary, we showed that 3D spatio-temporal gait parameters derived from inertial sensor data are viable to detect differences in the gait pattern of subjects with and without a macular degeneration simulation. We believe that this study provides the basis for an in-depth analysis regarding the impact of macular degeneration on gait.

  4. Multi-Sensor Cloud and Aerosol Retrieval Simulator and Remote Sensing from Model Parameters . Part 2; Aerosols

    Science.gov (United States)

    Wind, Galina; Da Silva, Arlindo M.; Norris, Peter M.; Platnick, Steven; Mattoo, Shana; Levy, Robert C.

    2016-01-01

    The Multi-sensor Cloud Retrieval Simulator (MCRS) produces a simulated radiance product from any high-resolution general circulation model with interactive aerosol as if a specific sensor such as the Moderate Resolution Imaging Spectroradiometer (MODIS) were viewing a combination of the atmospheric column and land ocean surface at a specific location. Previously the MCRS code only included contributions from atmosphere and clouds in its radiance calculations and did not incorporate properties of aerosols. In this paper we added a new aerosol properties module to the MCRS code that allows users to insert a mixture of up to 15 different aerosol species in any of 36 vertical layers. This new MCRS code is now known as MCARS (Multi-sensor Cloud and Aerosol Retrieval Simulator). Inclusion of an aerosol module into MCARS not only allows for extensive, tightly controlled testing of various aspects of satellite operational cloud and aerosol properties retrieval algorithms, but also provides a platform for comparing cloud and aerosol models against satellite measurements. This kind of two-way platform can improve the efficacy of model parameterizations of measured satellite radiances, allowing the assessment of model skill consistently with the retrieval algorithm. The MCARS code provides dynamic controls for appearance of cloud and aerosol layers. Thereby detailed quantitative studies of the impacts of various atmospheric components can be controlled. In this paper we illustrate the operation of MCARS by deriving simulated radiances from various data field output by the Goddard Earth Observing System version 5 (GEOS-5) model. The model aerosol fields are prepared for translation to simulated radiance using the same model sub grid variability parameterizations as are used for cloud and atmospheric properties profiles, namely the ICA technique. After MCARS computes modeled sensor radiances equivalent to their observed counterparts, these radiances are presented as input to

  5. 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 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...

  6. Design of Experiment and Analysis for the Joint Dynamic Allocation of Fires and Sensors (JDAFS) Simulation

    National Research Council Canada - National Science Library

    Freye, Jeffrey T

    2007-01-01

    ...) model, a low-resolution, Discrete Event Simulation Model with embedded optimization enables the analysis of many scenarios and factors to explore Joint Intelligence, Surveillance, and Reconnaissance (ISR) missions...

  7. Development and simulation of microfluidic Wheatstone bridge for high-precision sensor

    OpenAIRE

    Shipulya, N.D.; Konakov, S.A.; Krzhizhanovskaya, V.V.

    2016-01-01

    In this work we present the results of analytical modeling and 3D computer simulation of microfluidic Wheatstone bridge, which is used for high-accuracy measurements and precision instruments. We propose and simulate a new method of a bridge balancing process by changing the microchannel geometry. This process is based on the "etching in microchannel" technology we developed earlier (doi:10.1088/1742-6596/681/1/012035). Our method ensures a precise control of the flow rate and flow direction ...

  8. Test-beam measurements and simulation studies of thin pixel sensors for the CLIC vertex detector

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00574329; Dannheim, Dominik

    The multi-$TeV$ $e^{+}e^{-}$ Compact Linear Collider (CLIC) is one of the options for a future high-energy collider for the post-LHC era. It would allow for searches of new physics and simultaneously offer the possibility for precision measurements of standard model processes. The physics goals and experimental conditions at CLIC set high precision requirements on the vertex detector made of pixel detectors: a high pointing resolution of 3 $\\mu m$, very low mass of 0.2% $X_{0}$ per layer, 10 ns time stamping capability and low power dissipation of 50 mW/$cm^{2}$ compatible with air-flow cooling. In this thesis, hybrid assemblies with thin active-edge planar sensors are characterised through calibrations, laboratory and test-beam measurements. Prototypes containing 50 $\\mu m$ to 150 $\\mu m$ thin planar silicon sensors bump-bonded to Timepix3 readout ASICs with 55 $\\mu m$ pitch are characterised in test beams at the CERN SPS in view of their detection efficiency and single-point resolution. A digitiser for AllP...

  9. Tyre-road friction coefficient estimation based on tyre sensors and lateral tyre deflection: modelling, simulations and experiments

    Science.gov (United States)

    Hong, Sanghyun; Erdogan, Gurkan; Hedrick, Karl; Borrelli, Francesco

    2013-05-01

    The estimation of the tyre-road friction coefficient is fundamental for vehicle control systems. Tyre sensors enable the friction coefficient estimation based on signals extracted directly from tyres. This paper presents a tyre-road friction coefficient estimation algorithm based on tyre lateral deflection obtained from lateral acceleration. The lateral acceleration is measured by wireless three-dimensional accelerometers embedded inside the tyres. The proposed algorithm first determines the contact patch using a radial acceleration profile. Then, the portion of the lateral acceleration profile, only inside the tyre-road contact patch, is used to estimate the friction coefficient through a tyre brush model and a simple tyre model. The proposed strategy accounts for orientation-variation of accelerometer body frame during tyre rotation. The effectiveness and performance of the algorithm are demonstrated through finite element model simulations and experimental tests with small tyre slip angles on different road surface conditions.

  10. A Method to Simulate the Observed Surface Properties of Proton Irradiated Silicon Strip Sensors

    CERN Document Server

    INSPIRE-00335524; Bhardwaj, A.; Dalal, R.; Eber, R.; Eichhorn, T.; Lalwani, K.; Messineo, A.; Printz, M.; Ranjan, K.

    2015-04-23

    During the scheduled high luminosity upgrade of LHC, the world's largest particle physics accelerator at CERN, the position sensitive silicon detectors installed in the vertex and tracking part of the CMS experiment will face more intense radiation environment than the present system was designed for. To upgrade the tracker to required performance level, extensive measurements and simulations studies have already been carried out. A defect model of Synopsys Sentaurus TCAD simulation package for the bulk properties of proton irradiated devices has been producing simulations closely matching with measurements of silicon strip detectors. However, the model does not provide expected behavior due to the fluence increased surface damage. The solution requires an approach that does not affect the accurate bulk properties produced by the proton model, but only adds to it the required radiation induced properties close to the surface. These include the observed position dependency of the strip detector's charge collec...

  11. Simulations of Operation Dynamics of Different Type GaN Particle Sensors

    Science.gov (United States)

    Gaubas, Eugenijus; Ceponis, Tomas; Kalesinskas, Vidas; Pavlov, Jevgenij; Vysniauskas, Juozas

    2015-01-01

    The operation dynamics of the capacitor-type and PIN diode type detectors based on GaN have been simulated using the dynamic and drift-diffusion models. The drift-diffusion current simulations have been implemented by employing the software package Synopsys TCAD Sentaurus. The monopolar and bipolar drift regimes have been analyzed by using dynamic models based on the Shockley-Ramo theorem. The carrier multiplication processes determined by impact ionization have been considered in order to compensate carrier lifetime reduction due to introduction of radiation defects into GaN detector material. PMID:25751080

  12. Optimization of nanowire DNA sensor sensitivity using self-consistent simulation

    KAUST Repository

    Baumgartner, S

    2011-09-26

    In order to facilitate the rational design and the characterization of nanowire field-effect sensors, we have developed a model based on self-consistent charge-transport equations combined with interface conditions for the description of the biofunctionalized surface layer at the semiconductor/electrolyte interface. Crucial processes at the interface, such as the screening of the partial charges of the DNA strands and the influence of the angle of the DNA strands with respect to the nanowire, are computed by a Metropolis Monte Carlo algorithm for charged molecules at interfaces. In order to investigate the sensing mechanism of the device, we have computed the current-voltage characteristics, the electrostatic potential and the concentrations of electrons and holes. Very good agreement with measurements has been found and optimal device parameters have been identified. Our approach provides the capability to study the device sensitivity, which is of fundamental importance for reliable sensing. © IOP Publishing Ltd.

  13. Modular Architecture for Sensor Systems (MASS) : description, analysis, simulation, and implementation.

    Energy Technology Data Exchange (ETDEWEB)

    Stark, Douglas P.; Davis, Jesse Zehring; Edmonds, Nicholas

    2004-11-01

    A particular engineering aspect of distributed sensor networks that has not received adequate attention is the system level hardware architecture of the individual nodes of the network. A novel hardware architecture based on an idea of task specific modular computing is proposed to provide for both the high flexibility and low power consumption required for distributed sensing solutions. The power consumption of the architecture is mathematically analyzed against a traditional approach, and guidelines are developed for application scenarios that would benefit from using this new design. Furthermore a method of decentralized control for the modular system is developed and analyzed. Finally, a few policies for power minimization in the decentralized system are proposed and analyzed.

  14. Force sensor in simulated skin and neural model mimic tactile SAI afferent spiking response to ramp and hold stimuli.

    Science.gov (United States)

    Kim, Elmer K; Wellnitz, Scott A; Bourdon, Sarah M; Lumpkin, Ellen A; Gerling, Gregory J

    2012-07-23

    The next generation of prosthetic limbs will restore sensory feedback to the nervous system by mimicking how skin mechanoreceptors, innervated by afferents, produce trains of action potentials in response to compressive stimuli. Prior work has addressed building sensors within skin substitutes for robotics, modeling skin mechanics and neural dynamics of mechanotransduction, and predicting response timing of action potentials for vibration. The effort here is unique because it accounts for skin elasticity by measuring force within simulated skin, utilizes few free model parameters for parsimony, and separates parameter fitting and model validation. Additionally, the ramp-and-hold, sustained stimuli used in this work capture the essential features of the everyday task of contacting and holding an object. This systems integration effort computationally replicates the neural firing behavior for a slowly adapting type I (SAI) afferent in its temporally varying response to both intensity and rate of indentation force by combining a physical force sensor, housed in a skin-like substrate, with a mathematical model of neuronal spiking, the leaky integrate-and-fire. Comparison experiments were then conducted using ramp-and-hold stimuli on both the spiking-sensor model and mouse SAI afferents. The model parameters were iteratively fit against recorded SAI interspike intervals (ISI) before validating the model to assess its performance. Model-predicted spike firing compares favorably with that observed for single SAI afferents. As indentation magnitude increases (1.2, 1.3, to 1.4 mm), mean ISI decreases from 98.81 ± 24.73, 54.52 ± 6.94, to 41.11 ± 6.11 ms. Moreover, as rate of ramp-up increases, ISI during ramp-up decreases from 21.85 ± 5.33, 19.98 ± 3.10, to 15.42 ± 2.41 ms. Considering first spikes, the predicted latencies exhibited a decreasing trend as stimulus rate increased, as is observed in afferent recordings. Finally, the SAI afferent's characteristic response

  15. The effect of brain hematoma location on volumetric inductive phase shift spectroscopy of the brain with circular and magnetron sensor coils: a numerical simulation study

    International Nuclear Information System (INIS)

    Rojas, R; González, C A; Rubinsky, B

    2008-01-01

    This numerical simulation study addressed the effects of the location of a discrete brain hematoma on the volumetric inductive phase shift of the brain measured with an induction circular sensor coil and an induction magnetron sensor coil. The theoretical study simulates the brain cavity as a circular sphere transversely centered with respect to the circular and magnetron sensor coils. As a case study for the effects of hematoma location, we employed similar size simulated spherical hematomas placed at three different positions from the center of the brain outward. A three-dimensional finite element analysis of the field equations in the frequency range from 100 kHz to 100 MHz revealed a substantial effect of hematoma location on the ability of both the circular and magnetron sensors to detect the hematomas. In particular it was found that there are frequencies, which may be related to resonance, at which the occurrence of the hematomas has no effect on the volumetric inductive phase shift of the brain. Furthermore it was found that the relative sensitivity of circular and magnetron sensor coils with respect to the occurrence of hematoma varies with the location of the hematoma

  16. Slope Instability of the Earthen Levee in Boston, UK: Numerical Simulation and Sensor Data Analysis

    NARCIS (Netherlands)

    Melnikova, N.B.; Jordan, D.; Krzhizhanovskaya, V.V.; Sloot, P.M.A.

    2014-01-01

    The paper presents a slope stability analysis for a heterogeneous earthen levee in Boston, UK, which is prone to occasional slope failures under tidal loads. Dynamic behavior of the levee under tidal fluctuations was simulated using a finite element model of variably saturated linear elastic

  17. Simulation of photon and charge transport in X-ray imaging semiconductor sensors

    CERN Document Server

    Nilsson, H E; Hjelm, M; Bertilsson, K

    2002-01-01

    A fully stochastic model for the imaging properties of X-ray silicon pixel detectors is presented. Both integrating and photon counting configurations have been considered, as well as scintillator-coated structures. The model is based on three levels of Monte Carlo simulations; photon transport and absorption using MCNP, full band Monte Carlo simulation of charge transport and system level Monte Carlo simulation of the imaging performance of the detector system. In the case of scintillator-coated detectors, the light scattering in the detector layers has been simulated using a Monte Carlo method. The image resolution was found to be much lower in scintillator-coated systems due to large light spread in thick scintillator layers. A comparison between integrating and photon counting readout methods shows that the image resolution can be slightly enhanced using a photon-counting readout. In addition, the proposed model has been used to study charge-sharing effects on the energy resolution in photon counting dete...

  18. Quantification of a Low-Cost Stretchable Conductive Sensor Using an Expansion/Contraction Simulator Machine: A Step towards Validation of a Noninvasive Cardiac and Respiration Monitoring Prototype

    Directory of Open Access Journals (Sweden)

    Elham Shabani Varaki

    2017-10-01

    Full Text Available The use of wearable sensors in health monitoring is increasing dramatically, largely due to their convenience and low-cost. Understanding the accuracy of any given sensor is paramount to avoid potential misdiagnosis. Commercially available electro-resistive band (ERB sensors have been integrated into several newly developed wearable devices with a view to using these sensors to monitor a range of respiratory and cardiovascular metrics. Quantification of the ERBs is a necessary to step towards validation of these prototypes, as it provides valuable information, which could be exploited for compensation and ultimately, for improvement of their performance. Here, we present an analysis of the ERB sensors using an expansion/contraction simulator machine. Using the developed rig, the characteristics of four ERBs were compared with a linear displacement sensor (string potentiometer during continuous use over the course of four-and-a-half days to investigate the error and nonlinearity of the ERBs. The analysis of the recorded data includes calculation and comparison of the total harmonic distortions of the two sensors to quantify ERB nonlinearity. Moreover, comparisons between the peak-to-peak voltages and signal-to-noise ratios of the ERB and string potentiometer demonstrate the effect nonlinearity on these factors. This paper demonstrates the nonlinearity of ERBs and highlights the implications for their use in practice.

  19. Composite Cure Process Modeling and Simulations using COMPRO(Registered Trademark) and Validation of Residual Strains using Fiber Optics Sensors

    Science.gov (United States)

    Sreekantamurthy, Thammaiah; Hudson, Tyler B.; Hou, Tan-Hung; Grimsley, Brian W.

    2016-01-01

    Composite cure process induced residual strains and warping deformations in composite components present significant challenges in the manufacturing of advanced composite structure. As a part of the Manufacturing Process and Simulation initiative of the NASA Advanced Composite Project (ACP), research is being conducted on the composite cure process by developing an understanding of the fundamental mechanisms by which the process induced factors influence the residual responses. In this regard, analytical studies have been conducted on the cure process modeling of composite structural parts with varied physical, thermal, and resin flow process characteristics. The cure process simulation results were analyzed to interpret the cure response predictions based on the underlying physics incorporated into the modeling tool. In the cure-kinetic analysis, the model predictions on the degree of cure, resin viscosity and modulus were interpreted with reference to the temperature distribution in the composite panel part and tool setup during autoclave or hot-press curing cycles. In the fiber-bed compaction simulation, the pore pressure and resin flow velocity in the porous media models, and the compaction strain responses under applied pressure were studied to interpret the fiber volume fraction distribution predictions. In the structural simulation, the effect of temperature on the resin and ply modulus, and thermal coefficient changes during curing on predicted mechanical strains and chemical cure shrinkage strains were studied to understand the residual strains and stress response predictions. In addition to computational analysis, experimental studies were conducted to measure strains during the curing of laminated panels by means of optical fiber Bragg grating sensors (FBGs) embedded in the resin impregnated panels. The residual strain measurements from laboratory tests were then compared with the analytical model predictions. The paper describes the cure process

  20. Modelling and Simulation of the Knee Joint with a Depth Sensor Camera for Prosthetics and Movement Rehabilitation

    International Nuclear Information System (INIS)

    Risto, S; Kallergi, M

    2015-01-01

    The purpose of this project was to model and simulate the knee joint. A computer model of the knee joint was first created, which was controlled by Microsoft's Kinect for Windows. Kinect created a depth map of the knee and lower leg motion independent of lighting conditions through an infrared sensor. A combination of open source software such as Blender, Python, Kinect SDK and NI-Mate were implemented for the creation and control of the simulated knee based on movements of a live physical model. A physical size model of the knee and lower leg was also created, the movement of which was controlled remotely by the computer model and Kinect. The real time communication of the model and the robotic knee was achieved through programming in Python and Arduino language. The result of this study showed that Kinect in the modelling of human kinematics and can play a significant role in the development of prosthetics and other assistive technologies. (paper)

  1. 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.

  2. Model design and simulation of automatic sorting machine using proximity sensor

    Directory of Open Access Journals (Sweden)

    Bankole I. Oladapo

    2016-09-01

    Full Text Available The automatic sorting system has been reported to be complex and a global problem. This is because of the inability of sorting machines to incorporate flexibility in their design concept. This research therefore designed and developed an automated sorting object of a conveyor belt. The developed automated sorting machine is able to incorporate flexibility and separate species of non-ferrous metal objects and at the same time move objects automatically to the basket as defined by the regulation of the Programmable Logic Controllers (PLC with a capacitive proximity sensor to detect a value range of objects. The result obtained shows that plastic, wood, and steel were sorted into their respective and correct position with an average, sorting, time of 9.903 s, 14.072 s and 18.648 s respectively. The proposed developed model of this research could be adopted at any institution or industries, whose practices are based on mechatronics engineering systems. This is to guide the industrial sector in sorting of object and teaching aid to institutions and hence produce the list of classified materials according to the enabled sorting program commands.

  3. Simulating Physiological Response with a Passive Sensor Manikin and an Adaptive Thermal Manikin to Predict Thermal Sensation and Comfort

    Energy Technology Data Exchange (ETDEWEB)

    Rugh, John P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Chaney, Larry [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hepokoski, Mark [ThermoAnalytics Inc.; Curran, Allen [ThermoAnalytics Inc.; Burke, Richard [Measurement Technology NW; Maranville, Clay [Ford Motor Company

    2015-04-14

    Reliable assessment of occupant thermal comfort can be difficult to obtain within automotive environments, especially under transient and asymmetric heating and cooling scenarios. Evaluation of HVAC system performance in terms of comfort commonly requires human subject testing, which may involve multiple repetitions, as well as multiple test subjects. Instrumentation (typically comprised of an array of temperature sensors) is usually only sparsely applied across the human body, significantly reducing the spatial resolution of available test data. Further, since comfort is highly subjective in nature, a single test protocol can yield a wide variation in results which can only be overcome by increasing the number of test replications and subjects. In light of these difficulties, various types of manikins are finding use in automotive testing scenarios. These manikins can act as human surrogates from which local skin and core temperatures can be obtained, which are necessary for accurately predicting local and whole body thermal sensation and comfort using a physiology-based comfort model (e.g., the Berkeley Comfort Model). This paper evaluates two different types of manikins, i) an adaptive sweating thermal manikin, which is coupled with a human thermoregulation model, running in real-time, to obtain realistic skin temperatures; and, ii) a passive sensor manikin, which is used to measure boundary conditions as they would act on a human, from which skin and core temperatures can be predicted using a thermophysiological model. The simulated physiological responses and comfort obtained from both of these manikin-model coupling schemes are compared to those of a human subject within a vehicle cabin compartment transient heat-up scenario.

  4. Simulation of a precision irrigation-system based on a pedo-specific calibrated wireless soil moisture sensor network

    Science.gov (United States)

    Grashey-Jansen, S.; Timpf, S.

    2009-04-01

    In many climatic regions, the availability of water in soils determines to a large extent their agricultural productiveness. The hydrologic balance in soils is the result of complex physical processes, which are influenced by diverse geo-parameters with enormous spatial-temporal variations. Therefore, the measurement and quantitative based monitoring of the soil moisture dynamics has always been in the focus of soil physics and soil ecology. Especially in irrigated agricultural areas information about the actual soil water dynamics can deliver valuable data to optimize the irrigation practice with regard to volume and duration of irrigation. Novel irrigation equipment requires a fine control of the water distribution in the soil. One solution would be to have sensors near the plants' roots controlling the water inflow depending on the particular demand. Regarding the aspects of climatic change and the decrease of water resources, the term "precision irrigation" is being increasingly discussed. Only in this way we can meet the requirements due to the small-scale heterogeneities in soils. Such a precision irrigation must be based on objective and quantitative criteria, which focus primarily on the physical soil properties and hydrologic balances. This requires measuring arrangements with high spatial resolution in the horizontal and vertical directions. Such a dense soil-hydrological measuring network should ideally be composed of wireless micro-sensors, which are distributed in the investigated soil section and thereby collect data of relevant parameters in the pedosphere using a high temporal resolution and transmitting the information to a central logger-unit. This contribution will present a simulation-based approach of a precision irrigation-system with particular consideration of pedo-specific properties.

  5. Simulation Research Framework with Embedded Intelligent Algorithms for Analysis of Multi-Target, Multi-Sensor, High-Cluttered Environments

    Science.gov (United States)

    Hanlon, Nicholas P.

    nearly identical performance metrics at orders of magnitude faster in execution. Second, a fuzzy inference system is presented that alleviates air traffic controllers from information overload by utilizing flight plan data and radar/GPS correlation values to highlight aircraft that deviate from their intended routes. Third, a genetic algorithm optimizes sensor placement that is robust and capable of handling unexpected routes in the environment. Fourth, a fuzzy CUSUM algorithm more accurately detects and corrects aircraft mode changes. Finally, all the work is packaged in a holistic simulation research framework that provides evaluation and analysis of various multi-sensor, multi-target scenarios.

  6. Numerical simulation of mechatronic sensors and actuators finite elements for computational multiphysics

    CERN Document Server

    Kaltenbacher, Manfred

    2015-01-01

    Like the previous editions also the third edition of this book combines the detailed physical modeling of mechatronic systems and their precise numerical simulation using the Finite Element (FE) method. Thereby, the basic chapter concerning the Finite Element (FE) method is enhanced, provides now also a description of higher order finite elements (both for nodal and edge finite elements) and a detailed discussion of non-conforming mesh techniques. The author enhances and improves many discussions on principles and methods. In particular, more emphasis is put on the description of single fields by adding the flow field. Corresponding to these field, the book is augmented with the new chapter about coupled flow-structural mechanical systems. Thereby, the discussion of computational aeroacoustics is extended towards perturbation approaches, which allows a decomposition of flow and acoustic quantities within the flow region. Last but not least, applications are updated and restructured so that the book meets mode...

  7. A 3D CFD Simulation and Analysis of Flow-Induced Forces on Polymer Piezoelectric Sensors in a Chinese Liquors Identification E-Nose

    Directory of Open Access Journals (Sweden)

    Yu Gu

    2016-10-01

    Full Text Available Chinese liquors can be classified according to their flavor types. Accurate identification of Chinese liquor flavors is not always possible through professional sommeliers’ subjective assessment. A novel polymer piezoelectric sensor electric nose (e-nose can be applied to distinguish Chinese liquors because of its excellent ability in imitating human senses by using sensor arrays and pattern recognition systems. The sensor, based on the quartz crystal microbalance (QCM principle is comprised of a quartz piezoelectric crystal plate sandwiched between two specific gas-sensitive polymer coatings. Chinese liquors are identified by obtaining the resonance frequency value changes of each sensor using the e-nose. However, the QCM principle failed to completely account for a particular phenomenon: we found that the resonance frequency values fluctuated in the stable state. For better understanding the phenomenon, a 3D Computational Fluid Dynamics (CFD simulation using the finite volume method is employed to study the influence of the flow-induced forces to the resonance frequency fluctuation of each sensor in the sensor box. A dedicated procedure was developed for modeling the flow of volatile gas from Chinese liquors in a realistic scenario to give reasonably good results with fair accuracy. The flow-induced forces on the sensors are displayed from the perspective of their spatial-temporal and probability density distributions. To evaluate the influence of the fluctuation of the flow-induced forces on each sensor and ensure the serviceability of the e-nose, the standard deviation of resonance frequency value (SDF and the standard deviation of resultant forces (SDFy in y-direction (Fy are compared. Results show that the fluctuations of Fy are bound up with the resonance frequency values fluctuations. To ensure that the sensor's resonance frequency values are steady and only fluctuate slightly, in order to improve the identification accuracy of Chinese

  8. A Multirate Control Strategy to the Slow Sensors Problem: An Interactive Simulation Tool for Controller Assisted Design

    Science.gov (United States)

    Salt, Julián; Cuenca, Ángel; Palau, Francisco; Dormido, Sebastián

    2014-01-01

    In many control applications, the sensor technology used for the measurement of the variable to be controlled is not able to maintain a restricted sampling period. In this context, the assumption of regular and uniform sampling pattern is questionable. Moreover, if the control action updating can be faster than the output measurement frequency in order to fulfill the proposed closed loop behavior, the solution is usually a multirate controller. There are some known aspects to be careful of when a multirate system (MR) is going to be designed. The proper multiplicity between input-output sampling periods, the proper controller structure, the existence of ripples and others issues need to be considered. A useful way to save time and achieve good results is to have an assisted computer design tool. An interactive simulation tool to deal with MR seems to be the right solution. In this paper this kind of simulation application is presented. It allows an easy understanding of the performance degrading or improvement when changing the multirate sampling pattern parameters. The tool was developed using Sysquake, a Matlab-like language with fast execution and powerful graphic facilities. It can be delivered as an executable. In the paper a detailed explanation of MR treatment is also included and the design of four different MR controllers with flexible structure to be adapted to different schemes will also be presented. The Smith's predictor in these MR schemes is also explained, justified and used when time delays appear. Finally some interesting observations achieved using this interactive tool are included. PMID:24583971

  9. Modeling and Simulation of a Novel Relay Node Based Secure Routing Protocol Using Multiple Mobile Sink for Wireless Sensor Networks.

    Science.gov (United States)

    Perumal, Madhumathy; Dhandapani, Sivakumar

    2015-01-01

    Data gathering and optimal path selection for wireless sensor networks (WSN) using existing protocols result in collision. Increase in collision further increases the possibility of packet drop. Thus there is a necessity to eliminate collision during data aggregation. Increasing the efficiency is the need of the hour with maximum security. This paper is an effort to come up with a reliable and energy efficient WSN routing and secure protocol with minimum delay. This technique is named as relay node based secure routing protocol for multiple mobile sink (RSRPMS). This protocol finds the rendezvous point for optimal transmission of data using a "splitting tree" technique in tree-shaped network topology and then to determine all the subsequent positions of a sink the "Biased Random Walk" model is used. In case of an event, the sink gathers the data from all sources, when they are in the sensing range of rendezvous point. Otherwise relay node is selected from its neighbor to transfer packets from rendezvous point to sink. A symmetric key cryptography is used for secure transmission. The proposed relay node based secure routing protocol for multiple mobile sink (RSRPMS) is experimented and simulation results are compared with Intelligent Agent-Based Routing (IAR) protocol to prove that there is increase in the network lifetime compared with other routing protocols.

  10. SIMULATION AND ANALYSIS OF GREEDY ROUTING PROTOCOL IN VIEW OF ENERGY CONSUMPTION AND NETWORK LIFETIME IN THREE DIMENSIONAL UNDERWATER WIRELESS SENSOR NETWORK

    Directory of Open Access Journals (Sweden)

    SHEENA KOHLI

    2017-11-01

    Full Text Available Underwater Wireless Sensor Network (UWSN comprises of a number of miniature sized sensing devices deployed in the sea or ocean, connected by dint of acoustic links to each other. The sensors trap the ambient conditions and transmit the data from one end to another. For transmission of data in any medium, routing protocols play a crucial role. Moreover, being battery limited, an unavoidable parameter to be considered in operation and analysis of protocols is the network energy and the network lifetime. The paper discusses the greedy routing protocol for underwater wireless sensor networks. The simulation of this routing protocol also takes into consideration the characteristics of acoustic communication like attenuation, transmission loss, signal to noise ratio, noise, propagation delay. The results from these observations may be used to construct an accurate underwater communication model.

  11. Graphene oxide as sensitive layer in Love-wave surface acoustic wave sensors for the detection of chemical warfare agent simulants.

    Science.gov (United States)

    Sayago, Isabel; Matatagui, Daniel; Fernández, María Jesús; Fontecha, José Luis; Jurewicz, Izabela; Garriga, Rosa; Muñoz, Edgar

    2016-02-01

    A Love-wave device with graphene oxide (GO) as sensitive layer has been developed for the detection of chemical warfare agent (CWA) simulants. Sensitive films were fabricated by airbrushing GO dispersions onto Love-wave devices. The resulting Love-wave sensors detected very low CWA simulant concentrations in synthetic air at room temperature (as low as 0.2 ppm for dimethyl-methylphosphonate, DMMP, a simulant of sarin nerve gas, and 0.75 ppm for dipropylene glycol monomethyl ether, DPGME, a simulant of nitrogen mustard). High responses to DMMP and DPGME were obtained with sensitivities of 3087 and 760 Hz/ppm respectively. Very low limit of detection (LOD) values (9 and 40 ppb for DMMP and DPGME, respectively) were calculated from the achieved experimental data. The sensor exhibited outstanding sensitivity, good linearity and repeatability to all simulants tested. The detection mechanism is here explained in terms of hydrogen bonding formation between the tested CWA simulants and GO. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Dynamic Sensor Networks

    National Research Council Canada - National Science Library

    Schott, Brian

    2004-01-01

    ...: Declarative Languages and Execution Environment includes topographical soldier interface and a sensor network simulation environment for algorithm development, deployment planning, and operational support. Finally, Task 3...

  13. Agriculture/Hydroaquaoponic Bioscience Sensor - Mobile App with Simulations and Software for Industry and Science Education Curriculum Module

    OpenAIRE

    Christine M. Yukech

    2015-01-01

    There is a lot of technological buzz over the past few years regarding taking care of lettuce and hydroponic greenhouse plants and fish. We first review and discuss the recent technologies in the field of hydroponics, especially the hydroponic sensor curriculum project. The College of Engineering at The University of Akron developed a sensor that can detect hydrology, ph, electrical conductivity, nutrient levels, and temperature of hydroponic plants and aquaponic systems. The sensor can optim...

  14. Simulation of a thermoelectric gas sensor that determines hydrocarbon concentrations in exhausts and the light-off temperature of catalyst materials

    Directory of Open Access Journals (Sweden)

    T. Ritter

    2017-12-01

    Full Text Available Catalyst materials can be characterized with a thermoelectric gas sensor. Screen-printed thermopiles measure the temperature difference between an inert part of the planar sensor and a part that is coated with the catalyst material to be analyzed. If the overall sensor temperature is modulated, the catalytic activity of the material can be varied. Exothermic reactions that occur at the catalyst layer cause a temperature increase that can then be measured as a sensor voltage due to the Seebeck coefficient of the thermopiles. This mechanism can also be employed at stationary conditions at constant sensor temperature to measure gas concentrations. Then, the sensor signal changes linearly with the analyte concentration. Many variables influence the sensing performance, for example, the offset voltage due to asymmetric inflow and the resulting inhomogeneous temperature distributions are an issue. For even better understanding of the whole sensing principle, it is simulated in this study by a 3-D finite element model. By coupling all influencing physical effects (fluid flow, gas diffusion, heat transfer, chemical reactions, and electrical properties a model was set up that is able to mirror the sensor behavior precisely, as the comparison with experimental data shows. A challenging task was to mesh the geometry due to scaling problems regarding the resolution of the thin catalyst layer in the much larger gas tube. Therefore, a coupling of a 3-D and a 1-D geometry is shown. This enables to calculate the overall temperature distribution, fluid flow, and gas concentration distribution in the 3-D model, while a very accurate calculation of the chemical reactions is possible in a 1-D dimension. This work does not only give insight into the results at stationary conditions for varying feed gas concentrations and used substrate materials but shows also how various exhaust gas species behave under transient temperature modulation.

  15. Swath width study. A simulation assessment of costs and benefits of a sensor system for agricultural application

    Science.gov (United States)

    1979-01-01

    Satellites provide an excellent platform from which to observe crops on the scale and frequency required to provide accurate crop production estimates on a worldwide basis. Multispectral imaging sensors aboard these platforms are capable of providing data from which to derive acreage and production estimates. The issue of sensor swath width was examined. The quantitative trade trade necessary to resolve the combined issue of sensor swath width, number of platforms, and their orbits was generated and are included. Problems with different swath width sensors were analyzed and an assessment of system trade-offs of swath width versus number of satellites was made for achieving Global Crop Production Forecasting.

  16. Basic experiment of flux gate sensor. no. 2, comparison with simulation waves; Furakkusu geto jiryokukei no kisojikken. (2) Shumireshon hakei tono hikaku

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Tsuyoshi; Naito, Yoshihiro; Segawa, Hiroki

    1999-02-01

    While using a single shaft differential flux gate magnetometer to conduct magnetic inspection of a buried iron, a theoretical equation and simulation waves are known, but the real waves may be different from the theoretical waves depending on the characters of the magnetometer. In order to investigate the facts, a group of experiments are planned, and the measured waves are compared with the simulation waves of one experiment. The results are as follows. (1) It seems that S pole and N pole are apart from the ends of a magnet. (2) These poles may movable on the magnet due to the influences of another magnet. (3) While another magnet exists between a sensor and an objective magnet, the recording obtained by moving the sensor may largely differ from the recording obtained by moving the objective magnet. (translated by NEDO)

  17. Optical design of a novel instrument that uses the Hartmann-Shack sensor and Zernike polynomials to measure and simulate customized refraction correction surgery outcomes and patient satisfaction

    Science.gov (United States)

    Yasuoka, Fatima M. M.; Matos, Luciana; Cremasco, Antonio; Numajiri, Mirian; Marcato, Rafael; Oliveira, Otavio G.; Sabino, Luis G.; Castro N., Jarbas C.; Bagnato, Vanderlei S.; Carvalho, Luis A. V.

    2016-03-01

    An optical system that conjugates the patient's pupil to the plane of a Hartmann-Shack (HS) wavefront sensor has been simulated using optical design software. And an optical bench prototype is mounted using mechanical eye device, beam splitter, illumination system, lenses, mirrors, mirrored prism, movable mirror, wavefront sensor and camera CCD. The mechanical eye device is used to simulate aberrations of the eye. From this device the rays are emitted and travelled by the beam splitter to the optical system. Some rays fall on the camera CCD and others pass in the optical system and finally reach the sensor. The eye models based on typical in vivo eye aberrations is constructed using the optical design software Zemax. The computer-aided outcomes of each HS images for each case are acquired, and these images are processed using customized techniques. The simulated and real images for low order aberrations are compared using centroid coordinates to assure that the optical system is constructed precisely in order to match the simulated system. Afterwards a simulated version of retinal images is constructed to show how these typical eyes would perceive an optotype positioned 20 ft away. Certain personalized corrections are allowed by eye doctors based on different Zernike polynomial values and the optical images are rendered to the new parameters. Optical images of how that eye would see with or without corrections of certain aberrations are generated in order to allow which aberrations can be corrected and in which degree. The patient can then "personalize" the correction to their own satisfaction. This new approach to wavefront sensing is a promising change in paradigm towards the betterment of the patient-physician relationship.

  18. Simulation and performance evaluation of fiber optic sensor for detection of hepatic malignancies in human liver tissues

    Science.gov (United States)

    Sharma, Anuj K.; Gupta, Jyoti; Basu, Rikmantra

    2018-01-01

    A fiber optic sensor is proposed for the identification of healthy and cancerous liver tissues through determination of their corresponding refractive index values. Existing experimental results describing variation of complex refractive index of liver tissues in near infrared (NIR) spectral region are considered for theoretical calculations. The intensity interrogation method with chalcogenide fiber is considered. The sensor's performance is closely analyzed in terms of its sensitivity at multiple operating wavelengths falling in NIR region. Operating at shorter NIR wavelengths leads to greater sensitivity. The effect of design parameters (sensing region length and fiber core diameter), different launching conditions, and fiber glass materials on sensor's performance is examined. The proposed sensor has the potential to provide high sensitivity of liver tissue detection.

  19. Simulations

    CERN Document Server

    Ngada, Narcisse

    2015-06-15

    The complexity and cost of building and running high-power electrical systems make the use of simulations unavoidable. The simulations available today provide great understanding about how systems really operate. This paper helps the reader to gain an insight into simulation in the field of power converters for particle accelerators. Starting with the definition and basic principles of simulation, two simulation types, as well as their leading tools, are presented: analog and numerical simulations. Some practical applications of each simulation type are also considered. The final conclusion then summarizes the main important items to keep in mind before opting for a simulation tool or before performing a simulation.

  20. Modeling And Simulation Of Electrical Prevenion System Using Arduino Uno,Gsm Modem, And Acs712 Current Sensor

    Science.gov (United States)

    Khair, Ummul; Jabbar Lubis, Abdul; Agustha, Indra; Dharmawati; Zulfin, M.

    2017-12-01

    The current electricity needs is very primary, all objects including electronics require power, it encourages people not to be able to save electricity so the theft of electric power would be done. The use of ACS712 current sensor as the sensor with arduino uno would find out the power consumption continuously and prevent the theft of electricity because of the use of electricity which has been determined by PLN and the people fetl that it is not enough for every house, so the author made a tool for prevention of theft of electric power by using the arduino uno, buzzer, ACS712 current sensor, lcd, and relay then the power usage can be controlled according to the use to prevent the occurrence of theft of electricity so the use can be seen directly on the lcd 16x2and GSM modem to give information to employees of PLN so that it can reduceelectrical theft by the public.

  1. Simulation and analysis of Au-MgF2 structure in plasmonic sensor in near infrared spectral region

    Science.gov (United States)

    Sharma, Anuj K.

    2018-05-01

    Plasmonic sensor based on metal-dielectric combination of gold and MgF2 layers is studied in near infrared (NIR) spectral region. An emphasis is given on the effect of variable thickness of MgF2 layer in combination with operating wavelength and gold layer thickness on the sensor's performance in NIR. It is established that the variation in MgF2 thickness in connection with plasmon penetration depth leads to significant variation in sensor's performance. The analysis leads to a conclusion that taking smaller values of MgF2 layer thickness and operating at longer NIR wavelength leads to enhanced sensing performance. Also, fluoride glass can provide better sensing performance than chalcogenide glass and silicon substrate.

  2. Physico-Mathematical Simulation of a Homogeneous Thermal Field of Multichannel Raster Matrixes for Sensors of Oxygen

    Directory of Open Access Journals (Sweden)

    Vitalij Kotovskyi

    2015-01-01

    Full Text Available In the paper, an opportunity for the development of multichannel transcutaneous raster matrixes for sensors of oxygen on the basis of an electrochemical cell sensor is described. An analysis of the influence of heat sources on the distribution of the temperature pattern of a raster matrix for sensors of oxygen had been carried out, and their optimum configuration had been found. The application of such matrixes will enable one to obtain information about the distribution of the partial pressure of oxygen from the skin cover of the object of research in dynamics, to assess its functional health pattern in a more comprehensive way and to control the effect of possible remedial actions.

  3. Design, Simulation and Characteristics Research of the Interface Circuit based on nano-polysilicon thin films pressure sensor

    Science.gov (United States)

    Zhao, Xiaosong; Zhao, Xiaofeng; Yin, Liang

    2018-03-01

    This paper presents a interface circuit for nano-polysilicon thin films pressure sensor. The interface circuit includes consist of instrument amplifier and Analog-to-Digital converter (ADC). The instrumentation amplifier with a high common mode rejection ratio (CMRR) is implemented by three stages current feedback structure. At the same time, in order to satisfy the high precision requirements of pressure sensor measure system, the 1/f noise corner of 26.5 mHz can be achieved through chopping technology at a noise density of 38.2 nV/sqrt(Hz).Ripple introduced by chopping technology adopt continuous ripple reduce circuit (RRL), which achieves the output ripple level is lower than noise. The ADC achieves 16 bits significant digit by adopting sigma-delta modulator with fourth-order single-bit structure and digital decimation filter, and finally achieves high precision integrated pressure sensor interface circuit.

  4. Uav-Based Acquisition of 3d Point Cloud - a Comparison of a Low-Cost Laser Scanner and Sfm-Tools

    Science.gov (United States)

    Mader, D.; Blaskow, R.; Westfeld, P.; Maas, H.-G.

    2015-08-01

    The Project ADFEX (Adaptive Federative 3D Exploration of Multi Robot System) pursues the goal to develop a time- and cost-efficient system for exploration and monitoring task of unknown areas or buildings. A fleet of unmanned aerial vehicles equipped with appropriate sensors (laser scanner, RGB camera, near infrared camera, thermal camera) were designed and built. A typical operational scenario may include the exploration of the object or area of investigation by an UAV equipped with a laser scanning range finder to generate a rough point cloud in real time to provide an overview of the object on a ground station as well as an obstacle map. The data about the object enables the path planning for the robot fleet. Subsequently, the object will be captured by a RGB camera mounted on the second flying robot for the generation of a dense and accurate 3D point cloud by using of structure from motion techniques. In addition, the detailed image data serves as basis for a visual damage detection on the investigated building. This paper focuses on our experience with use of a low-cost light-weight Hokuyo laser scanner onboard an UAV. The hardware components for laser scanner based 3D point cloud acquisition are discussed, problems are demonstrated and analyzed, and a quantitative analysis of the accuracy potential is shown as well as in comparison with structure from motion-tools presented.

  5. Analysis of the Accuracy and Performance of a Continuous Glucose Monitoring Sensor Prototype: An In-Silico Study Using the UVA/PADOVA Type 1 Diabetes Simulator.

    Science.gov (United States)

    Breton, Marc D; Hinzmann, Rolf; Campos-Nañez, Enrique; Riddle, Susan; Schoemaker, Michael; Schmelzeisen-Redeker, Guenther

    2017-05-01

    Computer simulation has been shown over the past decade to be a powerful tool to study the impact of medical devices characteristics on clinical outcomes. Specifically, in type 1 diabetes (T1D), computer simulation platforms have all but replaced preclinical studies and are commonly used to study the impact of measurement errors on glycemia. We use complex mathematical models to represent the characteristics of 3 continuous glucose monitoring systems using previously acquired data. Leveraging these models within the framework of the UVa/Padova T1D simulator, we study the impact of CGM errors in 6 simulation scenarios designed to generate a wide variety of glycemic conditions. Assessment of the simulated accuracy of each different CGM systems is performed using mean absolute relative deviation (MARD) and precision absolute relative deviation (PARD). We also quantify the capacity of each system to detect hypoglycemic events. The simulated Roche CGM sensor prototype (RCGM) outperformed the 2 alternate systems (CGM-1 & CGM-2) in accuracy (MARD = 8% vs 11.4% vs 18%) and precision (PARD = 6.4% vs 9.4% vs 14.1%). These results held for all studied glucose and rate of change ranges. Moreover, it detected more than 90% of hypoglycemia, with a mean time lag less than 4 minutes (CGM-1: 86%/15 min, CGM-2: 57%/24 min). The RCGM system model led to strong performances in these simulation studies, with higher accuracy and precision than alternate systems. Its characteristics placed it firmly as a strong candidate for CGM based therapy, and should be confirmed in large clinical studies.

  6. Simulation of the sensor response of vacuummeters with sensitive elements based on multicomponent oxide nanomaterials with the fractal structure

    Science.gov (United States)

    Averin, I. A.; Igoshina, S. E.; Karmanov, A. A.; Pronin, I. A.; Moshnikov, V. A.; Terukov, E. I.

    2017-05-01

    We have proposed a mathematical model of the sensor response of vacuummeters with sensitive elements based on broadband semiconductor oxide with electrical conductivity of the n- and p-type, as well as the multicomponent oxide systems. The correctness of the model description of the dependence of the resistivity of nanomaterials synthesized by the sol-gel method and has the structure of spherical aggregates of fractal origin on the ambient pressure has been demonstrated. It has been shown that, taking into account the corrections, the developed model can be used to qualitatively describe the sensor response of nanomaterials based on two-component SiO2—SnO2 oxide systems with a labyrinth structure.

  7. A Computer Simulation Study of a Sensor-Based Heuristic Navigation for Three-Dimensional Rough Terrain with Obstacles

    Science.gov (United States)

    1989-06-01

    of this study, like most artificial intelligence applications , it was expected to be extended and corrected several times . LISP is suited for ill...the sensor. For the program implementation, LISP was adopted because of its properties for Artificial Intelligence applications , and the Symbolics...second conference on Artificial Intelligence Applications , pp. 148-155, 1985. 15. Kuan, D. T., Brooks, R. A., Zamiska, J. C., and Das, M., "Automatic Path

  8. ABS-SmartComAgri: An Agent-Based Simulator of Smart Communication Protocols in Wireless Sensor Networks for Debugging in Precision Agriculture.

    Science.gov (United States)

    García-Magariño, Iván; Lacuesta, Raquel; Lloret, Jaime

    2018-03-27

    Smart communication protocols are becoming a key mechanism for improving communication performance in networks such as wireless sensor networks. However, the literature lacks mechanisms for simulating smart communication protocols in precision agriculture for decreasing production costs. In this context, the current work presents an agent-based simulator of smart communication protocols for efficiently managing pesticides. The simulator considers the needs of electric power, crop health, percentage of alive bugs and pesticide consumption. The current approach is illustrated with three different communication protocols respectively called (a) broadcast, (b) neighbor and (c) low-cost neighbor. The low-cost neighbor protocol obtained a statistically-significant reduction in the need of electric power over the neighbor protocol, with a very large difference according to the common interpretations about the Cohen's d effect size. The presented simulator is called ABS-SmartComAgri and is freely distributed as open-source from a public research data repository. It ensures the reproducibility of experiments and allows other researchers to extend the current approach.

  9. ABS-SmartComAgri: An Agent-Based Simulator of Smart Communication Protocols in Wireless Sensor Networks for Debugging in Precision Agriculture

    Directory of Open Access Journals (Sweden)

    Iván García-Magariño

    2018-03-01

    Full Text Available Smart communication protocols are becoming a key mechanism for improving communication performance in networks such as wireless sensor networks. However, the literature lacks mechanisms for simulating smart communication protocols in precision agriculture for decreasing production costs. In this context, the current work presents an agent-based simulator of smart communication protocols for efficiently managing pesticides. The simulator considers the needs of electric power, crop health, percentage of alive bugs and pesticide consumption. The current approach is illustrated with three different communication protocols respectively called (a broadcast, (b neighbor and (c low-cost neighbor. The low-cost neighbor protocol obtained a statistically-significant reduction in the need of electric power over the neighbor protocol, with a very large difference according to the common interpretations about the Cohen’s d effect size. The presented simulator is called ABS-SmartComAgri and is freely distributed as open-source from a public research data repository. It ensures the reproducibility of experiments and allows other researchers to extend the current approach.

  10. Non-Destructive Monitoring of Rice by Hyperspectral In-Field Spectrometry and Uav-Based Remote Sensing: Case Study of Field-Grown Rice in North Rhine-Westphalia Germany

    Science.gov (United States)

    Willkomm, M.; Bolten, A.; Bareth, G.

    2016-06-01

    In the context of an increasing world population, the demand for agricultural crops is continuously rising. Especially rice plays a key role in food security, not only in Asia. To increase crop production of rice, either productivity of plants has to be improved or new cultivation areas have to be found. In this context, our study investigated crop growth of paddy rice (Oryza Sativa J.) in Germany. An experimental field in the vegetation period of 2014 with two nitrogen treatments was conducted using remote sensing methods. The research project focussed on two main aspects: (1) the potential of UAV-based and hyperspectral remote sensing methods to monitor selected growth parameters at different phenological stages; (2) the potential of paddy rice cultivation under the present climate condition in western Germany. We applied a low-cost UAV-system (Unmanned Aerial Vehicle) to generate high resolution Crop Surface Models (CSM). These were compared with hyperspectral in-field measurements and directly measured agronomic parameters (fresh and dry aboveground biomass (AGB), leaf-area-index (LAI) and plant nitrogen concentration (PNC)). For all acquisition dates we could determine single in-field structures in the CSM (e.g. distribution of hills) and different growth characteristics between the nitrogen treatments. Especially in the second half of the growing season, the plants with higher nitrogen availability were about 25 - 30 % larger. The plant height in the CSM correlates particularly with fresh AGB and the LAI (R2 > 0.8). Thus, the conducted methods for plant growth monitoring can be a contribution for precision agriculture approaches.

  11. NON-DESTRUCTIVE MONITORING OF RICE BY HYPERSPECTRAL IN-FIELD SPECTROMETRY AND UAV-BASED REMOTE SENSING: CASE STUDY OF FIELD-GROWN RICE IN NORTH RHINE-WESTPHALIA, GERMANY

    Directory of Open Access Journals (Sweden)

    M. Willkomm

    2016-06-01

    Full Text Available In the context of an increasing world population, the demand for agricultural crops is continuously rising. Especially rice plays a key role in food security, not only in Asia. To increase crop production of rice, either productivity of plants has to be improved or new cultivation areas have to be found. In this context, our study investigated crop growth of paddy rice (Oryza Sativa J. in Germany. An experimental field in the vegetation period of 2014 with two nitrogen treatments was conducted using remote sensing methods. The research project focussed on two main aspects: (1 the potential of UAV-based and hyperspectral remote sensing methods to monitor selected growth parameters at different phenological stages; (2 the potential of paddy rice cultivation under the present climate condition in western Germany. We applied a low-cost UAV-system (Unmanned Aerial Vehicle to generate high resolution Crop Surface Models (CSM. These were compared with hyperspectral in-field measurements and directly measured agronomic parameters (fresh and dry aboveground biomass (AGB, leaf-area-index (LAI and plant nitrogen concentration (PNC. For all acquisition dates we could determine single in-field structures in the CSM (e.g. distribution of hills and different growth characteristics between the nitrogen treatments. Especially in the second half of the growing season, the plants with higher nitrogen availability were about 25 – 30 % larger. The plant height in the CSM correlates particularly with fresh AGB and the LAI (R2 > 0.8. Thus, the conducted methods for plant growth monitoring can be a contribution for precision agriculture approaches.

  12. Quantitative Approach Based on Wearable Inertial Sensors to Assess and Identify Motion and Errors in Techniques Used during Training of Transfers of Simulated c-Spine-Injured Patients

    Directory of Open Access Journals (Sweden)

    Karina Lebel

    2018-01-01

    Full Text Available Patients with suspected spinal cord injuries undergo numerous transfers throughout treatment and care. Effective c-spine stabilization is crucial to minimize the impacts of the suspected injury. Healthcare professionals are trained to perform those transfers using simulation; however, the feedback on the manoeuvre is subjective. This paper proposes a quantitative approach to measure the efficacy of the c-spine stabilization and provide objective feedback during training. Methods. 3D wearable motion sensors are positioned on a simulated patient to capture the motion of the head and trunk during a training scenario. Spatial and temporal indicators associated with the motion can then be derived from the signals. The approach was developed and tested on data obtained from 21 paramedics performing the log-roll, a transfer technique commonly performed during prehospital and hospital care. Results. In this scenario, 55% of the c-spine motion could be explained by the difficulty of rescuers to maintain head and trunk alignment during the rotation part of the log-roll and their difficulty to initiate specific phases of the motion synchronously. Conclusion. The proposed quantitative approach has the potential to be used for personalized feedback during training sessions and could even be embedded into simulation mannequins to provide an innovative training solution.

  13. Use of a laser displacement sensor with a non-contact electromagnetic vibration device for assessment of simulated periodontal tissue conditions.

    Science.gov (United States)

    Kobayashi, Hiroshi; Yamaoka, Masaru; Hayashi, Makoto; Ogiso, Bunnai

    2016-01-01

    A non-contact electromagnetic vibration device (NEVD) was previously developed to monitor the condition of periodontal tissues by assessing mechanical parameters. This system requires placement of an accelerometer on the target tooth, to detect vibration. Using experimental tooth models, we evaluated the performance of an NEVD system with a laser displacement sensor (LDS), which does not need an accelerometer. Simulated teeth (polyacetal rods) were submerged at various depths in simulated bone (polyurethane or polyurethane foam) containing simulated periodontal ligament (tissue conditioner). Then, mechanical parameters (resonant frequency, elastic modulus, and viscosity coefficient) were assessed using the NEVD with the following detection methods: Group 1, measurement with an accelerometer; Group 2, measurement with an LDS in the presence of the accelerometer; and Group 3, measurement with an LDS in the absence of the accelerometer. Statistical analyses were performed using nonparametric methods (n = 5) (P < 0.05). The three mechanical parameters significantly increased with increasing depth. In addition, the mechanical parameters significantly differed between the polyurethane and polyurethane foam models. Although Groups 1 and 2 did not significantly differ, most all mechanical parameters in Group 3 were significantly larger and more distinguishable than those in Groups 1 and 2. The LDS was more accurate in measuring mechanical parameters and better able to differentiate periodontal tissue conditions. (J Oral Sci 58, 93-99, 2016).

  14. THE GRAPHICAL MODELING, SIMULATION AND REALIZATION OF AN EQUIPMENT WITH OPTO-REFLECTIVE SENSORS FOR THE MANAGEMENT OF URBAN PUBLIC TRANSPORT PASSENGERS

    Directory of Open Access Journals (Sweden)

    CRIȘAN Horea George

    2015-06-01

    Full Text Available The development of an equipment capable to carry out a real-time evaluation above loading of urban buses, allows the optimization of the urban transport vehicles distribution on a network segment, reducing waiting times, the passenger crowds in buses and at the same time decreasing the need of buses maintenance, issues with direct effects on the growth of the carriers economic profit. A solution based on optical detection is one that can generate results with high accuracy in relatively low cost conditions. This advantage can be obtained only if the constructive version of the equipment is properly designed, taking into account the geometric parameters of the light slots emitted and received by the sensors. Therefore, using three-dimensional CAD modelling, it was realized an optimal constructive variant. This graphical method also allows it the viewing, variation and synchronization of sensors geometrical parameters, so in this way, the equipment can produce the desired effect. Further, it has been carried out a graphical simulation of the designed equipment function, in order to validate the obtained results. Later, the designed equipment was achieved and tested under laboratory conditions, in order to be implemented and used under real conditions, on the buses of an urban public transport operator.

  15. Autonomous Inspection of Electrical Transmission Structures with Airborne UV Sensors - NASA Report on Dominion Virginia Power Flights of November 2016

    Science.gov (United States)

    Moore, Andrew J.; Schubert, Matthew; Nicholas Rymer

    2017-01-01

    The report details test and measurement flights to demonstrate autonomous UAV inspection of high voltage electrical transmission structures. A UAV built with commercial, off-the-shelf hardware and software, supplemented with custom sensor logging software, measured ultraviolet emissions from a test generator placed on a low-altitude substation and a medium-altitude switching tower. Since corona discharge precedes catastrophic electrical faults on high-voltage structures, detection and geolocation of ultraviolet emissions is needed to develop a UAV-based self-diagnosing power grid. Signal readings from an onboard ultraviolet sensor were validated during flight with a commercial corona camera. Geolocation was accomplished with onboard GPS; the UAV position was logged to a local ground station and transmitted in real time to a NASA server for tracking in the national airspace.

  16. Design and simulation of material-integrated distributed sensor processing with a code-based agent platform and mobile multi-agent systems.

    Science.gov (United States)

    Bosse, Stefan

    2015-02-16

    Multi-agent systems (MAS) can be used for decentralized and self-organizing data processing in a distributed system, like a resource-constrained sensor network, enabling distributed information extraction, for example, based on pattern recognition and self-organization, by decomposing complex tasks in simpler cooperative agents. Reliable MAS-based data processing approaches can aid the material-integration of structural-monitoring applications, with agent processing platforms scaled to the microchip level. The agent behavior, based on a dynamic activity-transition graph (ATG) model, is implemented with program code storing the control and the data state of an agent, which is novel. The program code can be modified by the agent itself using code morphing techniques and is capable of migrating in the network between nodes. The program code is a self-contained unit (a container) and embeds the agent data, the initialization instructions and the ATG behavior implementation. The microchip agent processing platform used for the execution of the agent code is a standalone multi-core stack machine with a zero-operand instruction format, leading to a small-sized agent program code, low system complexity and high system performance. The agent processing is token-queue-based, similar to Petri-nets. The agent platform can be implemented in software, too, offering compatibility at the operational and code level, supporting agent processing in strong heterogeneous networks. In this work, the agent platform embedded in a large-scale distributed sensor network is simulated at the architectural level by using agent-based simulation techniques.

  17. Design and Simulation of Material-Integrated Distributed Sensor Processing with a Code-Based Agent Platform and Mobile Multi-Agent Systems

    Directory of Open Access Journals (Sweden)

    Stefan Bosse

    2015-02-01

    Full Text Available Multi-agent systems (MAS can be used for decentralized and self-organizing data processing in a distributed system, like a resource-constrained sensor network, enabling distributed information extraction, for example, based on pattern recognition and self-organization, by decomposing complex tasks in simpler cooperative agents. Reliable MAS-based data processing approaches can aid the material-integration of structural-monitoring applications, with agent processing platforms scaled to the microchip level. The agent behavior, based on a dynamic activity-transition graph (ATG model, is implemented with program code storing the control and the data state of an agent, which is novel. The program code can be modified by the agent itself using code morphing techniques and is capable of migrating in the network between nodes. The program code is a self-contained unit (a container and embeds the agent data, the initialization instructions and the ATG behavior implementation. The microchip agent processing platform used for the execution of the agent code is a standalone multi-core stack machine with a zero-operand instruction format, leading to a small-sized agent program code, low system complexity and high system performance. The agent processing is token-queue-based, similar to Petri-nets. The agent platform can be implemented in software, too, offering compatibility at the operational and code level, supporting agent processing in strong heterogeneous networks. In this work, the agent platform embedded in a large-scale distributed sensor network is simulated at the architectural level by using agent-based simulation techniques.

  18. Sensor-Augmented Virtual Labs: Using Physical Interactions with Science Simulations to Promote Understanding of Gas Behavior

    Science.gov (United States)

    Chao, Jie; Chiu, Jennifer L.; DeJaegher, Crystal J.; Pan, Edward A.

    2016-02-01

    Deep learning of science involves integration of existing knowledge and normative science concepts. Past research demonstrates that combining physical and virtual labs sequentially or side by side can take advantage of the unique affordances each provides for helping students learn science concepts. However, providing simultaneously connected physical and virtual experiences has the potential to promote connections among ideas. This paper explores the effect of augmenting a virtual lab with physical controls on high school chemistry students' understanding of gas laws. We compared students using the augmented virtual lab to students using a similar sensor-based physical lab with teacher-led discussions. Results demonstrate that students in the augmented virtual lab condition made significant gains from pretest and posttest and outperformed traditional students on some but not all concepts. Results provide insight into incorporating mixed-reality technologies into authentic classroom settings.

  19. Molecular dynamics simulation of subnanometric tool-workpiece contact on a force sensor-integrated fast tool servo for ultra-precision microcutting

    International Nuclear Information System (INIS)

    Cai, Yindi; Chen, Yuan-Liu; Shimizu, Yuki; Ito, So; Gao, Wei; Zhang, Liangchi

    2016-01-01

    Highlights: • Subnanometric contact between a diamond tool and a copper workpiece surface is investigated by MD simulation. • A multi-relaxation time technique is proposed to eliminate the influence of the atom vibrations. • The accuracy of the elastic-plastic transition contact depth estimation is improved by observing the residual defects. • The simulation results are beneficial for optimization of the next-generation microcutting instruments. - Abstract: This paper investigates the contact characteristics between a copper workpiece and a diamond tool in a force sensor-integrated fast tool servo (FS-FTS) for single point diamond microcutting and in-process measurement of ultra-precision surface forms of the workpiece. Molecular dynamics (MD) simulations are carried out to identify the subnanometric elastic-plastic transition contact depth, at which the plastic deformation in the workpiece is initiated. This critical depth can be used to optimize the FS-FTS as well as the cutting/measurement process. It is clarified that the vibrations of the copper atoms in the MD model have a great influence on the subnanometric MD simulation results. A multi-relaxation time method is then proposed to reduce the influence of the atom vibrations based on the fact that the dominant vibration component has a certain period determined by the size of the MD model. It is also identified that for a subnanometric contact depth, the position of the tool tip for the contact force to be zero during the retracting operation of the tool does not correspond to the final depth of the permanent contact impression on the workpiece surface. The accuracy for identification of the transition contact depth is then improved by observing the residual defects on the workpiece surface after the tool retracting.

  20. Simulation

    DEFF Research Database (Denmark)

    Gould, Derek A; Chalmers, Nicholas; Johnson, Sheena J

    2012-01-01

    Recognition of the many limitations of traditional apprenticeship training is driving new approaches to learning medical procedural skills. Among simulation technologies and methods available today, computer-based systems are topical and bring the benefits of automated, repeatable, and reliable...... performance assessments. Human factors research is central to simulator model development that is relevant to real-world imaging-guided interventional tasks and to the credentialing programs in which it would be used....

  1. Autonomous sensor manager agents (ASMA)

    Science.gov (United States)

    Osadciw, Lisa A.

    2004-04-01

    Autonomous sensor manager agents are presented as an algorithm to perform sensor management within a multisensor fusion network. The design of the hybrid ant system/particle swarm agents is described in detail with some insight into their performance. Although the algorithm is designed for the general sensor management problem, a simulation example involving 2 radar systems is presented. Algorithmic parameters are determined by the size of the region covered by the sensor network, the number of sensors, and the number of parameters to be selected. With straight forward modifications, this algorithm can be adapted for most sensor management problems.

  2. Flexible magnetoimpedance sensor

    KAUST Repository

    Li, Bodong

    2015-03-01

    Flexible magnetoimpedance (MI) sensors fabricated using a NiFe/Cu/NiFe tri-layer on Kapton substrate have been studied. A customized flexible microstrip transmission line was employed to investigate the MI sensors\\'s magnetic field and frequency responses and their dependence on the sensors\\'s deflection. For the first time, the impedance characteristic is obtained through reflection coefficient analysis over a wide range of frequencies from 0.1 MHz to 3 GHz and for deflections ranging from zero curvature to a radius of 7.2 cm. The sensor element maintains a high MI ratio of up to 90% and magnetic sensitivity of up to 9.2%/Oe over different bending curvatures. The relationship between the curvature and material composition is discussed based on the magnetostriction effect and stress simulations. The sensor\\'s large frequency range, simple fabrication process and high sensitivity provide a great potential for flexible electronics and wireless applications.

  3. Designing and simulation smart multifunctional continuous logic device as a basic cell of advanced high-performance sensor systems with MIMO-structure

    Science.gov (United States)

    Krasilenko, Vladimir G.; Nikolskyy, Aleksandr I.; Lazarev, Alexander A.

    2015-01-01

    We have proposed a design and simulation of hardware realizations of smart multifunctional continuous logic devices (SMCLD) as advanced basic cells of the sensor systems with MIMO- structure for images processing and interconnection. The SMCLD realize function of two-valued, multi-valued and continuous logics with current inputs and current outputs. Such advanced basic cells realize function nonlinear time-pulse transformation, analog-to-digital converters and neural logic. We showed advantages of such elements. It's have a number of advantages: high speed and reliability, simplicity, small power consumption, high integration level. The conception of construction of SMCLD consists in the use of a current mirrors realized on 1.5μm technology CMOS transistors. Presence of 50÷70 transistors, 1 PD and 1 LED makes the offered circuits quite compact. The simulation results of NOT, MIN, MAX, equivalence (EQ), normalize summation, averaging and other functions, that implemented SMCLD, showed that the level of logical variables can change from 0.1μA to 10μA for low-power consumption variants. The SMCLD have low power consumption <1mW and processing time about 1÷11μS at supply voltage 2.4÷3.3V.

  4. Simulation

    CERN Document Server

    Ross, Sheldon

    2006-01-01

    Ross's Simulation, Fourth Edition introduces aspiring and practicing actuaries, engineers, computer scientists and others to the practical aspects of constructing computerized simulation studies to analyze and interpret real phenomena. Readers learn to apply results of these analyses to problems in a wide variety of fields to obtain effective, accurate solutions and make predictions about future outcomes. This text explains how a computer can be used to generate random numbers, and how to use these random numbers to generate the behavior of a stochastic model over time. It presents the statist

  5. A Reinforcement Learning Model Equipped with Sensors for Generating Perception Patterns: Implementation of a Simulated Air Navigation System Using ADS-B (Automatic Dependent Surveillance-Broadcast Technology

    Directory of Open Access Journals (Sweden)

    Santiago Álvarez de Toledo

    2017-01-01

    Full Text Available Over the last few decades, a number of reinforcement learning techniques have emerged, and different reinforcement learning-based applications have proliferated. However, such techniques tend to specialize in a particular field. This is an obstacle to their generalization and extrapolation to other areas. Besides, neither the reward-punishment (r-p learning process nor the convergence of results is fast and efficient enough. To address these obstacles, this research proposes a general reinforcement learning model. This model is independent of input and output types and based on general bioinspired principles that help to speed up the learning process. The model is composed of a perception module based on sensors whose specific perceptions are mapped as perception patterns. In this manner, similar perceptions (even if perceived at different positions in the environment are accounted for by the same perception pattern. Additionally, the model includes a procedure that statistically associates perception-action pattern pairs depending on the positive or negative results output by executing the respective action in response to a particular perception during the learning process. To do this, the model is fitted with a mechanism that reacts positively or negatively to particular sensory stimuli in order to rate results. The model is supplemented by an action module that can be configured depending on the maneuverability of each specific agent. The model has been applied in the air navigation domain, a field with strong safety restrictions, which led us to implement a simulated system equipped with the proposed model. Accordingly, the perception sensors were based on Automatic Dependent Surveillance-Broadcast (ADS-B technology, which is described in this paper. The results were quite satisfactory, and it outperformed traditional methods existing in the literature with respect to learning reliability and efficiency.

  6. A Reinforcement Learning Model Equipped with Sensors for Generating Perception Patterns: Implementation of a Simulated Air Navigation System Using ADS-B (Automatic Dependent Surveillance-Broadcast) Technology.

    Science.gov (United States)

    Álvarez de Toledo, Santiago; Anguera, Aurea; Barreiro, José M; Lara, Juan A; Lizcano, David

    2017-01-19

    Over the last few decades, a number of reinforcement learning techniques have emerged, and different reinforcement learning-based applications have proliferated. However, such techniques tend to specialize in a particular field. This is an obstacle to their generalization and extrapolation to other areas. Besides, neither the reward-punishment (r-p) learning process nor the convergence of results is fast and efficient enough. To address these obstacles, this research proposes a general reinforcement learning model. This model is independent of input and output types and based on general bioinspired principles that help to speed up the learning process. The model is composed of a perception module based on sensors whose specific perceptions are mapped as perception patterns. In this manner, similar perceptions (even if perceived at different positions in the environment) are accounted for by the same perception pattern. Additionally, the model includes a procedure that statistically associates perception-action pattern pairs depending on the positive or negative results output by executing the respective action in response to a particular perception during the learning process. To do this, the model is fitted with a mechanism that reacts positively or negatively to particular sensory stimuli in order to rate results. The model is supplemented by an action module that can be configured depending on the maneuverability of each specific agent. The model has been applied in the air navigation domain, a field with strong safety restrictions, which led us to implement a simulated system equipped with the proposed model. Accordingly, the perception sensors were based on Automatic Dependent Surveillance-Broadcast (ADS-B) technology, which is described in this paper. The results were quite satisfactory, and it outperformed traditional methods existing in the literature with respect to learning reliability and efficiency.

  7. Automated Registration Of Images From Multiple Sensors

    Science.gov (United States)

    Rignot, Eric J. M.; Kwok, Ronald; Curlander, John C.; Pang, Shirley S. N.

    1994-01-01

    Images of terrain scanned in common by multiple Earth-orbiting remote sensors registered automatically with each other and, where possible, on geographic coordinate grid. Simulated image of terrain viewed by sensor computed from ancillary data, viewing geometry, and mathematical model of physics of imaging. In proposed registration algorithm, simulated and actual sensor images matched by area-correlation technique.

  8. Ambient Sensors

    NARCIS (Netherlands)

    Börner, Dirk; Specht, Marcus

    2014-01-01

    This software sketches comprise two custom-built ambient sensors, i.e. a noise and a movement sensor. Both sensors measure an ambient value and process the values to a color gradient (green > yellow > red). The sensors were built using the Processing 1.5.1 development environment. Available under

  9. Detection, Emission Estimation and Risk Prediction of Forest Fires in China Using Satellite Sensors and Simulation Models in the Past Three Decades—An Overview

    Directory of Open Access Journals (Sweden)

    Cheng Liu

    2011-07-01

    Full Text Available Forest fires have major impact on ecosystems and greatly impact the amount of greenhouse gases and aerosols in the atmosphere. This paper presents an overview in the forest fire detection, emission estimation, and fire risk prediction in China using satellite imagery, climate data, and various simulation models over the past three decades. Since the 1980s, remotely-sensed data acquired by many satellites, such as NOAA/AVHRR, FY-series, MODIS, CBERS, and ENVISAT, have been widely utilized for detecting forest fire hot spots and burned areas in China. Some developed algorithms have been utilized for detecting the forest fire hot spots at a sub-pixel level. With respect to modeling the forest burning emission, a remote sensing data-driven Net Primary productivity (NPP estimation model was developed for estimating forest biomass and fuel. In order to improve the forest fire risk modeling in China, real-time meteorological data, such as surface temperature, relative humidity, wind speed and direction,have been used as the model input for improving prediction of forest fire occurrence and its behavior. Shortwave infrared (SWIR and near infrared (NIR channels of satellite sensors have been employed for detecting live fuel moisture content (FMC, and the Normalized Difference Water Index (NDWI was used for evaluating the forest vegetation condition and its moisture status.

  10. Detection, emission estimation and risk prediction of forest fires in China using satellite sensors and simulation models in the past three decades--an overview.

    Science.gov (United States)

    Zhang, Jia-Hua; Yao, Feng-Mei; Liu, Cheng; Yang, Li-Min; Boken, Vijendra K

    2011-08-01

    Forest fires have major impact on ecosystems and greatly impact the amount of greenhouse gases and aerosols in the atmosphere. This paper presents an overview in the forest fire detection, emission estimation, and fire risk prediction in China using satellite imagery, climate data, and various simulation models over the past three decades. Since the 1980s, remotely-sensed data acquired by many satellites, such as NOAA/AVHRR, FY-series, MODIS, CBERS, and ENVISAT, have been widely utilized for detecting forest fire hot spots and burned areas in China. Some developed algorithms have been utilized for detecting the forest fire hot spots at a sub-pixel level. With respect to modeling the forest burning emission, a remote sensing data-driven Net Primary productivity (NPP) estimation model was developed for estimating forest biomass and fuel. In order to improve the forest fire risk modeling in China, real-time meteorological data, such as surface temperature, relative humidity, wind speed and direction, have been used as the model input for improving prediction of forest fire occurrence and its behavior. Shortwave infrared (SWIR) and near infrared (NIR) channels of satellite sensors have been employed for detecting live fuel moisture content (FMC), and the Normalized Difference Water Index (NDWI) was used for evaluating the forest vegetation condition and its moisture status.

  11. Evaluation of Qualitative Changes in Simulated Periodontal Ligament and Alveolar Bone Using a Noncontact Electromagnetic Vibration Device with a Laser Displacement Sensor.

    Science.gov (United States)

    Kobayashi, Hiroshi; Hayashi, Makoto; Yamaoka, Masaru; Yasukawa, Takuya; Ibi, Haruna; Ogiso, Bunnai

    2016-01-01

    Evaluating periodontal tissue condition is an important diagnostic parameter in periodontal disease. Noncontact electromagnetic vibration device (NEVD) was previously developed to monitor this condition using mechanical parameters. However, this system requires accelerometer on the target tooth. This study assessed application of laser displacement sensor (LDS) to NEVD without accelerometer using experimental tooth models. Tooth models consisted of cylindrical rod, a tissue conditioner, and polyurethane or polyurethane foam to simulate tooth, periodontal ligament, and alveolar bone, respectively. Tissue conditioner was prepared by mixing various volumes of liquid with powder. Mechanical parameters (resonant frequency, elastic modulus, and coefficient of viscosity) were assessed using NEVD with the following methods: Group A, measurement with accelerometer; Group B, measurement with LDS in the presence of accelerometer; and Group C, measurement with LDS in the absence of accelerometer. Mechanical parameters significantly decreased with increasing liquid volume. Significant differences were also observed between the polyurethane and polyurethane foam models. Meanwhile, no statistically significant differences were observed between Groups A and B; however, most mechanical parameters in Group C were significantly larger and more distinguishable than those of Groups A and B. LDS could measure mechanical parameters more accurately and clearly distinguished the different periodontal ligament and alveolar bone conditions.

  12. Evaluation of Qualitative Changes in Simulated Periodontal Ligament and Alveolar Bone Using a Noncontact Electromagnetic Vibration Device with a Laser Displacement Sensor

    Directory of Open Access Journals (Sweden)

    Hiroshi Kobayashi

    2016-01-01

    Full Text Available Evaluating periodontal tissue condition is an important diagnostic parameter in periodontal disease. Noncontact electromagnetic vibration device (NEVD was previously developed to monitor this condition using mechanical parameters. However, this system requires accelerometer on the target tooth. This study assessed application of laser displacement sensor (LDS to NEVD without accelerometer using experimental tooth models. Tooth models consisted of cylindrical rod, a tissue conditioner, and polyurethane or polyurethane foam to simulate tooth, periodontal ligament, and alveolar bone, respectively. Tissue conditioner was prepared by mixing various volumes of liquid with powder. Mechanical parameters (resonant frequency, elastic modulus, and coefficient of viscosity were assessed using NEVD with the following methods: Group A, measurement with accelerometer; Group B, measurement with LDS in the presence of accelerometer; and Group C, measurement with LDS in the absence of accelerometer. Mechanical parameters significantly decreased with increasing liquid volume. Significant differences were also observed between the polyurethane and polyurethane foam models. Meanwhile, no statistically significant differences were observed between Groups A and B; however, most mechanical parameters in Group C were significantly larger and more distinguishable than those of Groups A and B. LDS could measure mechanical parameters more accurately and clearly distinguished the different periodontal ligament and alveolar bone conditions.

  13. On Packaging of MEMS. Simulation of Transfer Moulding and Packaging Stress and their Effect on a Family of piezo-resistive Pressure Sensors

    OpenAIRE

    Krondorfer, Rudolf H.

    2004-01-01

    Micro Electro Mechanical Systems (MEMS) produced to date include IR detectors, accelerometers, pressure sensors, micro lenses, actuators, chemical sensors, gear drives, RF devices, optical processor chips, micro robots and devices for biomedical analysis. The track for tomorrow has already been set and products like 3D TV, physician on a chip, lab on a chip, micro aircraft and food safety sensors will be developed when the technology matures and the market is ready. Todays MEMS fabricatio...

  14. Experimental and mathematical simulation techniques for determining an in-situ response testing method for neutron sensors used in reactor power plant protection systems

    International Nuclear Information System (INIS)

    Behbahani, A.

    1983-01-01

    An analytical neutron sensor response model and methods for transient response measurements of neutron sensors (compensated ionization chamber), including possible in-situ techniques have been developed and evaluated to meet the provisions of Draft Standard ISA Sd67.06, IEEE 338-1977, and NRC Guide 1.118. One in-situ method requires the perturbation of the high voltage detector (sensor) power supply and measurement of the sensor response. The response to a perturbation of the power supply is related to the response of the sensor to a transient change in neutron flux. Random signal analysis is another in-situ technique to monitor the neutron sensor response. In this method the power spectrum of the inherent fluctuations from the neutron sensor output (current in CIC) are measured and evaluated. Transient response techniques (including in-situ methods) are experimentally and analytically evaluated to identify the mechanisms which may cause degradation in the response of the neutron sensors. The objective of the experimental evaluation was to correlate the measured response time using transient radiation flux changes and power supply perturbation. The objective of the analytical model of the different sensor response was to predict response time and degradation mechanisms

  15. From large-eddy simulation to multi-UAVs sampling of shallow cumulus clouds

    Science.gov (United States)

    Lamraoui, Fayçal; Roberts, Greg; Burnet, Frédéric

    2016-04-01

    In-situ sampling of clouds that can provide simultaneous measurements at satisfying spatio-temporal resolutions to capture 3D small scale physical processes continues to present challenges. This project (SKYSCANNER) aims at bringing together cloud sampling strategies using a swarm of unmanned aerial vehicles (UAVs) based on Large-eddy simulation (LES). The multi-UAV-based field campaigns with a personalized sampling strategy for individual clouds and cloud fields will significantly improve the understanding of the unresolved cloud physical processes. An extensive set of LES experiments for case studies from ARM-SGP site have been performed using MesoNH model at high resolutions down to 10 m. The carried out simulations led to establishing a macroscopic model that quantifies the interrelationship between micro- and macrophysical properties of shallow convective clouds. Both the geometry and evolution of individual clouds are critical to multi-UAV cloud sampling and path planning. The preliminary findings of the current project reveal several linear relationships that associate many cloud geometric parameters to cloud related meteorological variables. In addition, the horizontal wind speed indicates a proportional impact on cloud number concentration as well as triggering and prolonging the occurrence of cumulus clouds. In the framework of the joint collaboration that involves a Multidisciplinary Team (including institutes specializing in aviation, robotics and atmospheric science), this model will be a reference point for multi-UAVs sampling strategies and path planning.

  16. 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.

  17. Sim4CV: A Photo-Realistic Simulator for Computer Vision Applications

    KAUST Repository

    Müller, Matthias

    2018-03-24

    We present a photo-realistic training and evaluation simulator (Sim4CV) (http://www.sim4cv.org) with extensive applications across various fields of computer vision. Built on top of the Unreal Engine, the simulator integrates full featured physics based cars, unmanned aerial vehicles (UAVs), and animated human actors in diverse urban and suburban 3D environments. We demonstrate the versatility of the simulator with two case studies: autonomous UAV-based tracking of moving objects and autonomous driving using supervised learning. The simulator fully integrates both several state-of-the-art tracking algorithms with a benchmark evaluation tool and a deep neural network architecture for training vehicles to drive autonomously. It generates synthetic photo-realistic datasets with automatic ground truth annotations to easily extend existing real-world datasets and provides extensive synthetic data variety through its ability to reconfigure synthetic worlds on the fly using an automatic world generation tool.

  18. UE4Sim: A Photo-Realistic Simulator for Computer Vision Applications

    KAUST Repository

    Mueller, Matthias

    2017-08-19

    We present a photo-realistic training and evaluation simulator (UE4Sim) with extensive applications across various fields of computer vision. Built on top of the Unreal Engine, the simulator integrates full featured physics based cars, unmanned aerial vehicles (UAVs), and animated human actors in diverse urban and suburban 3D environments. We demonstrate the versatility of the simulator with two case studies: autonomous UAV-based tracking of moving objects and autonomous driving using supervised learning. The simulator fully integrates both several state-of-the-art tracking algorithms with a benchmark evaluation tool and a deep neural network (DNN) architecture for training vehicles to drive autonomously. It generates synthetic photo-realistic datasets with automatic ground truth annotations to easily extend existing real-world datasets and provides extensive synthetic data variety through its ability to reconfigure synthetic worlds on the fly using an automatic world generation tool.

  19. Metamaterial Sensors

    Directory of Open Access Journals (Sweden)

    Jing Jing Yang

    2013-01-01

    Full Text Available Metamaterials have attracted a great deal of attention due to their intriguing properties, as well as the large potential applications for designing functional devices. In this paper, we review the current status of metamaterial sensors, with an emphasis on the evanescent wave amplification and the accompanying local field enhancement characteristics. Examples of the sensors are given to illustrate the principle and the performance of the metamaterial sensor. The paper concludes with an optimistic outlook regarding the future of metamaterial sensor.

  20. Advanced Magnetoimpedance Sensors

    KAUST Repository

    Li, Bodong

    2015-02-01

    This thesis is concerned with the advanced topics of thin film magnetoimpedance (MI) sensors. The author proposes and develops novel MI sensors that target on the challenges arising from emerging applications such as flexible electronics, passive wireless sensing, etc. In the study of flexible MI sensor, the investigated sensors of NiFe/Cu/NiFe tri-layersare fabricated on three flexible substrates having different surface roughness: Kapton, standard and premiumphotopaper. Sensitivity versus substrate roughness analysis is carried out for the selection of optimal substrate material. The high magnetic sensing performance is achieved by using Kapton substrate. Stress simulation, incorporated with the theory of magnetostriction effect, reveals the material composition of Ni/Fe being as a key factor of the stress dependent MI effect for the flexible MI sensors. In the development of MI-SAW device for passive wireless magnetic field sensing, NiFe/Cu/NiFe tri-layersand interdigital transducers(IDT) are designed and fabricated on a single piece of LiNbO3substrate, providing a high degree of integration and the advantage of standard microfabrication. The double-electrodeIDT has been utilized and proven to have an optimal sensing performance in comparison to the bi-directional IDT design. The optimized high frequency performance of the thin film MI sensor results in a MI-SAW passive wireless magnetic sensor with high magnetic sensitivity comparing to the MI microwire approach. Benefiting from the high degree of integration of the MI thin film element, in the following study, two additional sensing elements are integrated to the SAW device to have a multifunctional passive wireless sensor with extended temperature and humidity sensing capabilities. Analytical models havebeen developed to eliminate the crossovers of different sensing signals through additional reference IDTs, resulting in a multifunctional passive wireless sensor with the capability of detecting all three

  1. Smart sensors

    Science.gov (United States)

    Corsi, Carlo

    2006-08-01

    The term "Smart Sensors" refer to sensors which contain both sensing and signal processing capabilities with objectives ranging from simple viewing to sophisticated remote sensing, surveillance, search/track, weapon guidance, robotics, perceptronics and intelligence applications. In a broad sense, they include any sensor systems covering the whole electromagnetic spectrum: this paper deals specifically with a new class of smart sensors in infrared spectral bands whose developments started some years ago, when it was recognized that the rapid advances of "very large scale integration" (VLSI) processor technology and mosaic infrared detector array technology could be combined to develop new generations of infrared smart sensor systems with much improved performance. So, sophisticated signal processing operations have been developed for these new systems by integrating microcomputers and other VLSI signal processors within or next to the sensor arrays on the same focal plane avoiding complex computing located far away from the sensors. Recently this approach is achieving higher goals by a new and revolutionary sensors concept which introduce inside the sensor some of the basic function of living eyes, such as dynamic stare, dishomogenity compensation, spatial and temporal filtering. New objectives and requirements of these new focal plane processors are presented for this type of new infrared smart sensor systems. This paper is concerned with the processing techniques for only the front end of the focal plane processing, namely, the enhancement of target-to-noise ratio by background clutter suppression and the improvement in target detection by "smart" and pattern correlation threshold.

  2. The Different Sensitive Behaviors of a Hydrogen-Bond Acidic Polymer-Coated SAW Sensor for Chemical Warfare Agents and Their Simulants

    Directory of Open Access Journals (Sweden)

    Yin Long

    2015-07-01

    Full Text Available A linear hydrogen-bond acidic (HBA linear functionalized polymer (PLF, was deposited onto a bare surface acoustic wave (SAW device to fabricate a chemical sensor. Real-time responses of the sensor to a series of compounds including sarin (GB, dimethyl methylphosphonate (DMMP, mustard gas (HD, chloroethyl ethyl sulphide (2-CEES, 1,5-dichloropentane (DCP and some organic solvents were studied. The results show that the sensor is highly sensitive to GB and DMMP, and has low sensitivity to HD and DCP, as expected. However, the sensor possesses an unexpected high sensitivity toward 2-CEES. This good sensing performance can’t be solely or mainly attributed to the dipole-dipole interaction since the sensor is not sensitive to some high polarity solvents. We believe the lone pair electrons around the sulphur atom of 2-CEES provide an electron-rich site, which facilitates the formation of hydrogen bonding between PLF and 2-CEES. On the contrary, the electron cloud on the sulphur atom of the HD molecule is offset or depleted by its two neighbouring strong electron-withdrawing groups, hence, hydrogen bonding can hardly be formed.

  3. The Different Sensitive Behaviors of a Hydrogen-Bond Acidic Polymer-Coated SAW Sensor for Chemical Warfare Agents and Their Simulants.

    Science.gov (United States)

    Long, Yin; Wang, Yang; Du, Xiaosong; Cheng, Luhua; Wu, Penglin; Jiang, Yadong

    2015-07-28

    A linear hydrogen-bond acidic (HBA) linear functionalized polymer (PLF), was deposited onto a bare surface acoustic wave (SAW) device to fabricate a chemical sensor. Real-time responses of the sensor to a series of compounds including sarin (GB), dimethyl methylphosphonate (DMMP), mustard gas (HD), chloroethyl ethyl sulphide (2-CEES), 1,5-dichloropentane (DCP) and some organic solvents were studied. The results show that the sensor is highly sensitive to GB and DMMP, and has low sensitivity to HD and DCP, as expected. However, the sensor possesses an unexpected high sensitivity toward 2-CEES. This good sensing performance can't be solely or mainly attributed to the dipole-dipole interaction since the sensor is not sensitive to some high polarity solvents. We believe the lone pair electrons around the sulphur atom of 2-CEES provide an electron-rich site, which facilitates the formation of hydrogen bonding between PLF and 2-CEES. On the contrary, the electron cloud on the sulphur atom of the HD molecule is offset or depleted by its two neighbouring strong electron-withdrawing groups, hence, hydrogen bonding can hardly be formed.

  4. Sensor web

    Science.gov (United States)

    Delin, Kevin A. (Inventor); Jackson, Shannon P. (Inventor)

    2011-01-01

    A Sensor Web formed of a number of different sensor pods. Each of the sensor pods include a clock which is synchronized with a master clock so that all of the sensor pods in the Web have a synchronized clock. The synchronization is carried out by first using a coarse synchronization which takes less power, and subsequently carrying out a fine synchronization to make a fine sync of all the pods on the Web. After the synchronization, the pods ping their neighbors to determine which pods are listening and responded, and then only listen during time slots corresponding to those pods which respond.

  5. Gas Sensor

    KAUST Repository

    Luebke, Ryan

    2015-01-22

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  6. A Sounding Rocket Attitude Determination Algorithm Suitable for Implementation Using Low Cost Sensors

    National Research Council Canada - National Science Library

    Charlton, Mark

    2003-01-01

    .... Sun sensor, magnetometer, and rate sensor measurements are simulated. A quaternion formulation is used to avoid singularity problems associated with Euler angles and other three-parameter approaches...

  7. Surface Embedded Metal Oxide Sensors (SEMOS)

    DEFF Research Database (Denmark)

    Jespersen, Jesper Lebæk; Talat Ali, Syed; Pleth Nielsen, Lars

    is the second and main part of the project. The main challenges in developing metal oxide sensors are proper choice of the material, sensor location and fabrication technique due to lifetime and cross sensitivity issues in harsh environment where the problems like de-bonding or some kind of diffusion......SEMOS is a joint project between Aalborg University, Danish Technological Institute and Danish Technical University in which micro temperature sensors and metal oxide-based gas sensors are developed and tested in a simulated fuel cell environment as well as in actual working fuel cells. Initially...... complex and sensors are not easily implemented in the construction. Hence sensor interface and sensor position must therefore be chosen carefully in order to make the sensors as non-intrusive as possible. Metal Oxide Sensors (MOX) for measuring H2, O2 and CO concentration in a fuel cell environment...

  8. Building a High-Precision 2D Hydrodynamic Flood Model Using UAV Photogrammetry and Sensor Network Monitoring

    Directory of Open Access Journals (Sweden)

    Jakub Langhammer

    2017-11-01

    Full Text Available This paper explores the potential of the joint application of unmanned aerial vehicle (UAV-based photogrammetry and an automated sensor network for building a hydrodynamic flood model of a montane stream. UAV-based imagery was used for three-dimensional (3D photogrammetric reconstruction of the stream channel, achieving a resolution of 1.5 cm/pixel. Automated ultrasonic water level gauges, operating with a 10 min interval, were used as a source of hydrological data for the model calibration, and the MIKE 21 hydrodynamic model was used for building the flood model. Three different horizontal schematizations of the channel—an orthogonal grid, curvilinear grid, and flexible mesh—were used to evaluate the effect of spatial discretization on the results. The research was performed on Javori Brook, a montane stream in the Sumava (Bohemian Forest Mountains, Czech Republic, Central Europe, featuring a fast runoff response to precipitation events and that is located in a core zone of frequent flooding. The studied catchments have been, since 2007, equipped with automated water level gauges and, since 2013, under repeated UAV monitoring. The study revealed the high potential of these data sources for applications in hydrodynamic modeling. In addition to the ultra-high levels of spatial and temporal resolution, the major contribution is in the method’s high operability, enabling the building of highly detailed flood models even in remote areas lacking conventional monitoring. The testing of the data sources and model setup indicated the limitations of the UAV reconstruction of the stream bathymetry, which was completed by the geodetic-grade global navigation satellite system (GNSS measurements. The testing of the different model domain schematizations did not indicate the substantial differences that are typical for conventional low-resolution data, proving the high reliability of the tested modeling workflow.

  9. Chemical sensors

    International Nuclear Information System (INIS)

    Hubbard, C.W.; Gordon, R.L.

    1987-05-01

    The revolution in analytical chemistry promised by recent developments in the field of chemical sensors has potential for significant positive impact on both research and production activities conducted by and for the Department of Energy. Analyses which were, in the past, performed only with a roomful of expensive equipment can now be performed with miniature solid-state electronic devices or small optical probes. Progress in the development of chemical sensors has been rapid, and the field is currently growing at a great rate. In accordance, Pacific Northwest Laboratory initiated a survey of recent literature so that contributors to active programs in research on analytical methods could be made aware of principles and applications of this new technology. This report presents the results of that survey. The sensors discussed here are divided into three types: micro solid-state devices, optical sensors, and piezoelectric crystal devices. The report is divided into three corresponding sections. The first section, ''Micro Solid-State Devices,'' discusses the design, operation, and application of electronic sensors that are produced in much the same way as standard solid-state electronic devices. The second section, ''Optrodes,'' covers the design and operation of chemical sensors that use fiber optics to detect chemically induced changes in optical properties. The final section, ''Piezoelectric Crystal Detectors,'' discusses two types of chemical sensors that depend on the changes in the properties of an oscillating piezoelectric crystal to detect the presence of certain materials. Advantages and disadvantages of each type of sensor are summarized in each section

  10. Evaluation of Qualitative Changes in Simulated Periodontal Ligament and Alveolar Bone Using a Noncontact Electromagnetic Vibration Device with a Laser Displacement Sensor

    OpenAIRE

    Kobayashi, Hiroshi; Hayashi, Makoto; Yamaoka, Masaru; Yasukawa, Takuya; Ibi, Haruna; Ogiso, Bunnai

    2016-01-01

    Evaluating periodontal tissue condition is an important diagnostic parameter in periodontal disease. Noncontact electromagnetic vibration device (NEVD) was previously developed to monitor this condition using mechanical parameters. However, this system requires accelerometer on the target tooth. This study assessed application of laser displacement sensor (LDS) to NEVD without accelerometer using experimental tooth models. Tooth models consisted of cylindrical rod, a tissue conditioner, and p...

  11. ARBRES: Light-Weight CW/FM SAR Sensors for Small UAVs

    Directory of Open Access Journals (Sweden)

    Xavier Fabregas

    2013-03-01

    Full Text Available This paper describes a pair of compact CW/FM airborne SAR systems for small UAV-based operation (wingspan of 3.5 m for low-cost testing of innovative SAR concepts. Two different SAR instruments, using the C and X bands, have been developed in the context of the ARBRES project, each of them achieving a payload weight below 5 Kg and a volume of 13.5 dm3 (sensor and controller. Every system has a dual receiving channel which allows operation in interferometric or polarimetric modes. Planar printed array antennas are used in both sensors for easy system integration and better isolation between transmitter and receiver subsystems. First experimental tests on board a 3.2 m wingspan commercial radio-controlled aircraft are presented. The SAR images of a field close to an urban area have been focused using a back-projection algorithm. Using the dual channel capability, a single pass interferogram and Digital Elevation Model (DEM has been obtained which agrees with the scene topography. A simple Motion Compensation (MoCo module, based on the information from an Inertial+GPS unit, has been included to compensate platform motion errors with respect to the nominal straight trajectory.

  12. ARBRES: light-weight CW/FM SAR sensors for small UAVs.

    Science.gov (United States)

    Aguasca, Albert; Acevo-Herrera, Rene; Broquetas, Antoni; Mallorqui, Jordi J; Fabregas, Xavier

    2013-03-06

    This paper describes a pair of compact CW/FM airborne SAR systems for small UAV-based operation (wingspan of 3.5 m) for low-cost testing of innovative SAR concepts. Two different SAR instruments, using the C and X bands, have been developed in the context of the ARBRES project, each of them achieving a payload weight below 5 Kg and a volume of 13.5 dm3 (sensor and controller). Every system has a dual receiving channel which allows operation in interferometric or polarimetric modes. Planar printed array antennas are used in both sensors for easy system integration and better isolation between transmitter and receiver subsystems. First experimental tests on board a 3.2 m wingspan commercial radio-controlled aircraft are presented. The SAR images of a field close to an urban area have been focused using a back-projection algorithm. Using the dual channel capability, a single pass interferogram and Digital Elevation Model (DEM) has been obtained which agrees with the scene topography. A simple Motion Compensation (MoCo) module, based on the information from an Inertial+GPS unit, has been included to compensate platform motion errors with respect to the nominal straight trajectory.

  13. Game theoretic sensor management for target tracking

    Science.gov (United States)

    Shen, Dan; Chen, Genshe; Blasch, Erik; Pham, Khanh; Douville, Philip; Yang, Chun; Kadar, Ivan

    2010-04-01

    This paper develops and evaluates a game-theoretic approach to distributed sensor-network management for target tracking via sensor-based negotiation. We present a distributed sensor-based negotiation game model for sensor management for multi-sensor multi-target tacking situations. In our negotiation framework, each negotiation agent represents a sensor and each sensor maximizes their utility using a game approach. The greediness of each sensor is limited by the fact that the sensor-to-target assignment efficiency will decrease if too many sensor resources are assigned to a same target. It is similar to the market concept in real world, such as agreements between buyers and sellers in an auction market. Sensors are willing to switch targets so that they can obtain their highest utility and the most efficient way of applying their resources. Our sub-game perfect equilibrium-based negotiation strategies dynamically and distributedly assign sensors to targets. Numerical simulations are performed to demonstrate our sensor-based negotiation approach for distributed sensor management.

  14. MASM: a market architecture for sensor management in distributed sensor networks

    Science.gov (United States)

    Viswanath, Avasarala; Mullen, Tracy; Hall, David; Garga, Amulya

    2005-03-01

    Rapid developments in sensor technology and its applications have energized research efforts towards devising a firm theoretical foundation for sensor management. Ubiquitous sensing, wide bandwidth communications and distributed processing provide both opportunities and challenges for sensor and process control and optimization. Traditional optimization techniques do not have the ability to simultaneously consider the wildly non-commensurate measures involved in sensor management in a single optimization routine. Market-oriented programming provides a valuable and principled paradigm to designing systems to solve this dynamic and distributed resource allocation problem. We have modeled the sensor management scenario as a competitive market, wherein the sensor manager holds a combinatorial auction to sell the various items produced by the sensors and the communication channels. However, standard auction mechanisms have been found not to be directly applicable to the sensor management domain. For this purpose, we have developed a specialized market architecture MASM (Market architecture for Sensor Management). In MASM, the mission manager is responsible for deciding task allocations to the consumers and their corresponding budgets and the sensor manager is responsible for resource allocation to the various consumers. In addition to having a modified combinatorial winner determination algorithm, MASM has specialized sensor network modules that address commensurability issues between consumers and producers in the sensor network domain. A preliminary multi-sensor, multi-target simulation environment has been implemented to test the performance of the proposed system. MASM outperformed the information theoretic sensor manager in meeting the mission objectives in the simulation experiments.

  15. Automotive sensors

    Science.gov (United States)

    Marek, Jiri; Illing, Matthias

    2003-01-01

    Sensors are an essential component of most electronic systems in the car. They deliver input parameters for comfort features, engine and emission control as well as for the active and passive safety systems. New technologies such as silicon micromachining play an important role for the introduction of these sensors in all vehicle classes. The importance and use of these sensor technologies in today"s automotive applications will be shown in this article. Finally an outlook on important current developments and new functions in the car will be given.

  16. Piezoceramic Sensors

    CERN Document Server

    Sharapov, Valeriy

    2011-01-01

    This book presents the latest and complete information about various types of piezosensors. A sensor is a converter of the measured physical size to an electric signal. Piezoelectric transducers and sensors are based on piezoelectric effects. They have proven to be versatile tools for the measurement of various processes. They are used for quality assurance, process control and for research and development in many different industries. In each area of application specific requirements to the parameters of transducers and sensors are developed. This book presents the fundamentals, technical des

  17. Optimal sensor configuration for complex systems

    DEFF Research Database (Denmark)

    Sadegh, Payman; Spall, J. C.

    1998-01-01

    configuration is based on maximizing the overall sensor response while minimizing the correlation among the sensor outputs. The procedure for sensor configuration is based on simultaneous perturbation stochastic approximation (SPSA). SPSA avoids the need for detailed modeling of the sensor response by simply......Considers the problem of sensor configuration for complex systems. Our approach involves definition of an appropriate optimality criterion or performance measure, and description of an efficient and practical algorithm for achieving the optimality objective. The criterion for optimal sensor...... relying on observed responses as obtained by limited experimentation with test sensor configurations. We illustrate the approach with the optimal placement of acoustic sensors for signal detection in structures. This includes both a computer simulation study for an aluminum plate, and real...

  18. Radiation sensors

    International Nuclear Information System (INIS)

    Wykes, J.S.; Adsley, I.

    1981-01-01

    Radiation detectors, suitable for use in industrial environments, eg coal mines are claimed. At least two scintillation crystals are mounted on a resilient support material, preferably silicone rubber. The sensors are both robust and compact. (U.K.)

  19. Potential of convective rainfall estimation from lightning data in the context of the "Simulation of Meteosat Third Generation - Lightning Imager through Tropical Rainfall Measuring Mission - Lightning Imaging Sensor data

    Science.gov (United States)

    Biron, D.; de Leonibus, L.; Zauli, F.; Melfi, D.; Laquale, P.; Labate, D.

    2009-04-01

    The Centro Nazionale di Meteorologia e Climatologia Aeronautica recently hosted a fellowship sponsored by Selex Galileo, with the intent to study and perform a simulation of Meteosat Third Generation - Lightning Imager (MTG-LI) sensor behavior through Tropical Rainfall Measuring Mission - Lightning Imaging Sensor data (TRMM-LIS). For the next generation of earth observation geostationary satellite, major operating agencies are planning to insert an optical imaging mission, that continuously observes lightning pulses in the atmosphere; EUMETSAT has decided in recent years that one of the candidate mission to be flown on MTG is LI, a Lightning Imager. MTG-LI mission has no Meteosat Second Generation heritage, but users need to evaluate the possible real time data output of the instrument to agree in inserting it on MTG payload. Authors took the expected LI design from MTG Mission Requirement Document, and reprocess real lightning dataset, acquired from space by TRMM-LIS instrument, to produce a simulated MTG-LI lightning dataset. The simulation is performed in several run, varying Minimum Detectable Energy, taking into account processing steps from event detection to final lightning information. A definition of the specific meteorological requirements is given from the potential use in meteorology of lightning final information for convection estimation and numerical cloud modeling. Study results show the range of instrument requirements relaxation which lead to minimal reduction in the final lightning information. Potential in convective rainfall estimation over ocean from space lightning observation is addressed and a retrieval example making use of lightning ground network data is reported both with validation by radar observation.

  20. Contactless Quality Monitoring Sensor Based on Electrical Conductivity Measurements

    Directory of Open Access Journals (Sweden)

    Armin SATZ

    2010-09-01

    Full Text Available A first prototype of a contactless conductivity sensor for AdBlue® quality monitoring is presented. Based on a detailed sensor mode analysis it is shown that capacitive sensors can be designed to sense electrical liquid conductivity. The sensor design process is based on a sensor model, which allows simulating capacitive senor responses for arbitrary electrode and liquid tank geometries. Finally, temperature induced errors are estimated.

  1. Mechanoluminescent Contact Type Sensor

    Directory of Open Access Journals (Sweden)

    A. K. Yefremov

    2017-01-01

    Full Text Available Mechanoluminescent sensing elements convert mechanical stress into optical radiation. Advantages of such sensors are the ability to generate an optical signal, solid-state, simple structure, and resistance to electromagnetic interference. Mechanoluminescent sensor implementations can possess the concentrated and distributed sensitivity, thereby allowing us to detect the field of mechanical stresses distributed across the area and in volume. Most modern semiconductor photo-detectors can detect mechanoluminescent radiation, so there are no difficulties to provide its detection when designing the mechanoluminescent sensing devices. Mechanoluminescent substances have especial sensitivity to shock loads, and this effect can be used to create a fuse the structure of which includes a target contact type sensor with a photosensitive actuator. The paper briefly describes the theoretical basics of mechanoluminiscence: a light signal emerges from the interaction of crystalline phosphor luminescence centers with electrically charged dislocations, moving due to the deformation of the crystal. A mathematical model of the mechanoluminescent conversion is represented as a functional interaction between parameters of the mechanical shock excitation and the sensor light emission. Examples of computing the optical mechanoluminescent output signal depending on the duration and peak level of impulse load are given. It is shown that the luminous flux, generated by mechanoluminescent sensing element when there is an ammunition-target collision causes the current emerging in photo-detector (photodiode that is sufficient for a typical actuator of the fuse train to operate. The potential possibility to create a contact target type sensor based on the light-sensitive mechanoluminescent sensor was proved by the calculation and simulation results.

  2. Radiation sensor

    International Nuclear Information System (INIS)

    Brown, W.L.; Geronime, R.L.

    1977-01-01

    Radiation sensor and thermocouple, respectively, which can be used for reactor in-core instrumentation. The radiation sensor consists of an inconel conductor wire and rhodium emitter wire, the thermocouple of two intertwined alumel or chromel wires. Both are arranged in the center of a metal tube relative to which they are separated by an insulator made of SiO 2 fibers. This insulator is first introduced as a loose fabric between the radiation sensor and the thermocouple, respectively, and the metal tube and then compacted to a density of 35-73% of pure SiO 2 by drawing the tube. There is no need for soldering or welding. The insulation resistivity at room temperature ist between 10 14 and 10 15 ohms. (ORU) [de

  3. Simulation of spectral bands of the MERIS sensor to estimate chlorophyll-a concentrations in a reservoir of the semi-arid region = Simulação de bandas espectrais do sensor MERIS para estimativas das concentrações de clorofila-a em reservatório da região semiárida

    Directory of Open Access Journals (Sweden)

    Fernando Bezerra Lopes

    2016-07-01

    Full Text Available Nowadays, the monitoring of water is essential for the sustainability and better management of water resources. The use of remote sensing data is important, since it allows evaluation of dynamic problems in aquatic systems, such as the eutrophication of bodies of water and suspended sediment. The aim of this study was to estimate chlorophyll-a concentrations in a reservoir of the semi-arid region of Brazil using simulated orbital-sensor data, as an aid in the management of water resources. The study area corresponded to the Orós reservoir, in the State of Ceará, Brazil. Water samples for analysis of the chlorophyll-a and measurements of the spectral radiance of the aquatic system were collected from 20 points. The radiance was measured by spectroradiometer. The data were collected in June and August of 2011. The model using three bands of the MERIS sensor (7, 9 and 10 presented an R2 of 0.84. For the two-band model (7 and 9, the value of R2 was 0.85. The waters of the Orós reservoir were all classified as eutrophic. The main optically active component in modelling the shape of the spectra was chlorophyll-a. The models showed a mean absolute error (MAE of 3.45 and 3.61 μg L-1 for the three- and two-band models respectively. The models displayed high coefficients of determination, i.e. the simulations show the feasibility of estimating chlorophyll-a concentration from the data of the MERIS orbital sensor. = O monitoramento da água nos dias atuais é essencial para a sustentabilidade e para a melhor gestão dos recursos hídricos. O uso de dados de sensoriamento remoto é relevante, uma vez que permite a avaliação de problemas dinâmicos em sistemas aquáticos, tais como a eutrofização de corpos de água e dos sedimentos em suspensão. Objetivou-se estimar as concentrações de clorofila-a em reservatório da região semiárida do Brasil, usando dados simulados de sensor orbital, como suporte à gestão dos recursos hídricos. A área de

  4. Target Coverage in Wireless Sensor Networks with Probabilistic Sensors

    Science.gov (United States)

    Shan, Anxing; Xu, Xianghua; Cheng, Zongmao

    2016-01-01

    Sensing coverage is a fundamental problem in wireless sensor networks (WSNs), which has attracted considerable attention. Conventional research on this topic focuses on the 0/1 coverage model, which is only a coarse approximation to the practical sensing model. In this paper, we study the target coverage problem, where the objective is to find the least number of sensor nodes in randomly-deployed WSNs based on the probabilistic sensing model. We analyze the joint detection probability of target with multiple sensors. Based on the theoretical analysis of the detection probability, we formulate the minimum ϵ-detection coverage problem. We prove that the minimum ϵ-detection coverage problem is NP-hard and present an approximation algorithm called the Probabilistic Sensor Coverage Algorithm (PSCA) with provable approximation ratios. To evaluate our design, we analyze the performance of PSCA theoretically and also perform extensive simulations to demonstrate the effectiveness of our proposed algorithm. PMID:27618902

  5. Pharmaceutical Pill Counting and Inspection Using a Capacitive Sensor

    Directory of Open Access Journals (Sweden)

    Ganesan LETCHUMANAN

    2008-01-01

    Full Text Available A capacitive sensor for high-speed counting and inspection of pharmaceutical products is proposed and evaluated. The sensor is based on a patented Electrostatic Field Sensor (EFS device, previously developed by Sparc Systems Limited. However, the sensor head proposed in this work has a significantly different geometry and has been designed with a rectangular inspection aperture of 160mm × 21mm, which best meets applications where a larger count throughput is required with a single sensor. Finite element modelling has been used to simulate the electrostatic fields generated within the sensor, and as a design tool for optimising the sensor head configuration. The actual and simulated performance of the sensor is compared and analysed in terms of the sensor performance at discriminating between damaged products or detection of miscount errors.

  6. Diehl weapons lab works on sensors, lasers, flight control

    Science.gov (United States)

    Flume, W.

    1986-06-01

    The Diehl Weapons Laboratory activities include: warheads, ballistics, sensor technology, mensuration technology, and simulation. The facilities at the laboratory are described. Research projects are summarized.

  7. Simulation of Guardrings

    International Nuclear Information System (INIS)

    Benyamna, M.

    2007-01-01

    The strategy for simulation SILVACO is to provide an evaluation of the values of the internal capacitances of the sensor to validate the assumption of a cross talk and to study the influence of the quardrings on this phenomenon

  8. Microcantilever Sensors

    Science.gov (United States)

    Lang, Hans Peter; Gerber, Christoph

    Microfabricated cantilevers have been used in atomic force microscopy for the topography imaging of non-conductive surfaces for more than 20 years. Cantilever beams without tips have proved their applicability in recent years as miniaturized, ultrasensitive, and fast-responding sensors for applications in chemistry, physics, biochemistry, and medicine. Microcantilever sensors respond by bending due to the absorption of molecules. A shift in resonance frequency also occurs. They can be operated in different environments such as gaseous environment, liquids, or vacuum. In gas, microcantilever sensors can be operated as an artificial nose, whereby the bending pattern of a microfabricated array of eight polymer-coated silicon cantilevers is characteristic of the different vapors from solvents, flavors, and beverages. When operated in a liquid, microcantilever sensors are able to detect biochemical reactions. Each cantilever is functionalized with a specific biochemical probe receptor, sensitive for detection of the corresponding target molecule. Applications lie in the fields of label- and amplification-free detection of DNA hybridization, the detection of proteins as well as antigen-antibody reactions, and the detection of larger entities, such as bacteria and fungi.

  9. Imaging Sensors

    Indian Academy of Sciences (India)

    Natural and Manmade Sensors. A less well-known instance of how we have been anticipated by evolution refers to the compound eye of insects like bees, wasps, etc. and of arthropods like the horseshoe crab (Figure 1). The compound eye consists of several thousand ommatidia. Each ommatidium is a separate detector, ...

  10. GMI sensor

    Czech Academy of Sciences Publication Activity Database

    Platil, A.; Malátek, M.; Ripka, P.; Kraus, Luděk

    2004-01-01

    Roč. 110, 1-3 (2004), s. 341-342 ISSN 0924-4247 Institutional research plan: CEZ:AV0Z1010914 Keywords : magnetic sensors * GMI * magnetometer Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.462, year: 2004

  11. Gas sensor

    Science.gov (United States)

    Schmid, Andreas K.; Mascaraque, Arantzazu; Santos, Benito; de la Figuera, Juan

    2014-09-09

    A gas sensor is described which incorporates a sensor stack comprising a first film layer of a ferromagnetic material, a spacer layer, and a second film layer of the ferromagnetic material. The first film layer is fabricated so that it exhibits a dependence of its magnetic anisotropy direction on the presence of a gas, That is, the orientation of the easy axis of magnetization will flip from out-of-plane to in-plane when the gas to be detected is present in sufficient concentration. By monitoring the change in resistance of the sensor stack when the orientation of the first layer's magnetization changes, and correlating that change with temperature one can determine both the identity and relative concentration of the detected gas. In one embodiment the stack sensor comprises a top ferromagnetic layer two mono layers thick of cobalt deposited upon a spacer layer of ruthenium, which in turn has a second layer of cobalt disposed on its other side, this second cobalt layer in contact with a programmable heater chip.

  12. Sensor Saturation Compensated Smoothing Algorithm for Inertial Sensor Based Motion Tracking

    Directory of Open Access Journals (Sweden)

    Quoc Khanh Dang

    2014-05-01

    Full Text Available In this paper, a smoothing algorithm for compensating inertial sensor saturation is proposed. The sensor saturation happens when a sensor measures a value that is larger than its dynamic range. This can lead to a considerable accumulated error. To compensate the lost information in saturated sensor data, we propose a smoothing algorithm in which the saturation compensation is formulated as an optimization problem. Based on a standard smoothing algorithm with zero velocity intervals, two saturation estimation methods were proposed. Simulation and experiments prove that the proposed methods are effective in compensating the sensor saturation.

  13. Optical fibre microwire sensors

    OpenAIRE

    Brambilla, G.; Belal, Mohammad; Jung, Y.; Song, Z.; Xu, F.; Newson, T.P.; Richardson, D.J.

    2011-01-01

    This paper reviews sensing applications of optical fibre microwires and nanowires. In addition to the usual benefits of sensors based on optical fibres, these sensors are extremely compact and have fast response speeds. In this review sensors will be grouped in three categories according to their morphology: linear sensors, resonant sensors and tip sensors. While linear and resonant sensors mainly exploit the fraction of power propagating outside the microwire physical boundary, tip sensors t...

  14. Energy modelling in sensor networks

    Directory of Open Access Journals (Sweden)

    D. Schmidt

    2007-06-01

    Full Text Available Wireless sensor networks are one of the key enabling technologies for the vision of ambient intelligence. Energy resources for sensor nodes are very scarce. A key challenge is the design of energy efficient communication protocols. Models of the energy consumption are needed to accurately simulate the efficiency of a protocol or application design, and can also be used for automatic energy optimizations in a model driven design process. We propose a novel methodology to create models for sensor nodes based on few simple measurements. In a case study the methodology was used to create models for MICAz nodes. The models were integrated in a simulation environment as well as in a SDL runtime framework of a model driven design process. Measurements on a test application that was created automatically from an SDL specification showed an 80% reduction in energy consumption compared to an implementation without power saving strategies.

  15. Embedding Sensors During Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Sbriglia, Lexey Raylene [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-10

    This PowerPoint presentation had the following headings: Fused deposition modeling (FDM); Open source 3D printing; Objectives; Vibration analysis; Equipment; Design; Material choices; Failure causes, such as tension, bubbling; Potential solutions; Simulations; Embedding the sensors; LabView programming; Alternate data acquisition; Problem and proposed solution; and, Conclusions

  16. A Novel Permanent Magnetic Angular Acceleration Sensor

    Directory of Open Access Journals (Sweden)

    Hao Zhao

    2015-07-01

    Full Text Available Angular acceleration is an important parameter for status monitoring and fault diagnosis of rotary machinery. Therefore, we developed a novel permanent magnetic angular acceleration sensor, which is without rotation angle limitations and could directly measure the instantaneous angular acceleration of the rotating system. The sensor rotor only needs to be coaxially connected with the rotating system, which enables convenient sensor installation. For the cup structure of the sensor rotor, it has a relatively small rotational inertia. Due to the unique mechanical structure of the sensor, the output signal of the sensor can be directed without a slip ring, which avoids signal weakening effect. In this paper, the operating principle of the sensor is described, and simulated using finite element method. The sensitivity of the sensor is calibrated by torsional pendulum and angle sensor, yielding an experimental result of about 0.88 mV/(rad·s−2. Finally, the angular acceleration of the actual rotating system has been tested, using both a single-phase asynchronous motor and a step motor. Experimental result confirms the operating principle of the sensor and indicates that the sensor has good practicability.

  17. Semiconductor sensors

    International Nuclear Information System (INIS)

    Hartmann, Frank

    2011-01-01

    Semiconductor sensors have been around since the 1950s and today, every high energy physics experiment has one in its repertoire. In Lepton as well as Hadron colliders, silicon vertex and tracking detectors led to the most amazing physics and will continue doing so in the future. This contribution tries to depict the history of these devices exemplarily without being able to honor all important developments and installations. The current understanding of radiation damage mechanisms and recent R and D topics demonstrating the future challenges and possible technical solutions for the SLHC detectors are presented. Consequently semiconductor sensor candidates for an LHC upgrade and a future linear collider are also briefly introduced. The work presented here is a collage of the work of many individual silicon experts spread over several collaborations across the world.

  18. Novel sensors for food inspection modelling, fabrication and experimentation

    CERN Document Server

    Abdul Rahman, Mohd Syaifudin; Yu, Pak-Lam

    2014-01-01

    This book addresses presents recent developments of novel planar interdigital sensors for food inspection. It covers the fundamentals of sensors, their design, modelling and simulations, fabrications, characterizations, experimental investigations and analyses. This book will be useful for the engineers and researchers especially higher undergraduate, postgraduate students as well as practitioners working on the development of Electromagnetic Sensors.

  19. Vibrissa Sensor

    Science.gov (United States)

    2016-09-30

    a seal whisker was joined at its base to a spring gimbal and subjected to flow conditions. Attorney Docket No. 300119 3 of 11 Fluid flow and the...whisker were then observed by a camera . In other research, an artificial whisker fabricated by stereolithography was fastened to a piezoelectric...the art. For example, membrane 38 could be replaced by a gimbal . The gimbal could be made from elastomeric material. Non-magnetic sensors could

  20. Wireless sensors and sensor networks for homeland security applications.

    Science.gov (United States)

    Potyrailo, Radislav A; Nagraj, Nandini; Surman, Cheryl; Boudries, Hacene; Lai, Hanh; Slocik, Joseph M; Kelley-Loughnane, Nancy; Naik, Rajesh R

    2012-11-01

    New sensor technologies for homeland security applications must meet the key requirements of sensitivity to detect agents below risk levels, selectivity to provide minimal false-alarm rates, and response speed to operate in high throughput environments, such as airports, sea ports, and other public places. Chemical detection using existing sensor systems is facing a major challenge of selectivity. In this review, we provide a brief summary of chemical threats of homeland security importance; focus in detail on modern concepts in chemical sensing; examine the origins of the most significant unmet needs in existing chemical sensors; and, analyze opportunities, specific requirements, and challenges for wireless chemical sensors and wireless sensor networks (WSNs). We further review a new approach for selective chemical sensing that involves the combination of a sensing material that has different response mechanisms to different species of interest, with a transducer that has a multi-variable signal-transduction ability. This new selective chemical-sensing approach was realized using an attractive ubiquitous platform of battery-free passive radio-frequency identification (RFID) tags adapted for chemical sensing. We illustrate the performance of RFID sensors developed in measurements of toxic industrial materials, humidity-independent detection of toxic vapors, and detection of chemical-agent simulants, explosives, and strong oxidizers.

  1. Error propagation analysis for a sensor system

    International Nuclear Information System (INIS)

    Yeater, M.L.; Hockenbury, R.W.; Hawkins, J.; Wilkinson, J.

    1976-01-01

    As part of a program to develop reliability methods for operational use with reactor sensors and protective systems, error propagation analyses are being made for each model. An example is a sensor system computer simulation model, in which the sensor system signature is convoluted with a reactor signature to show the effect of each in revealing or obscuring information contained in the other. The error propagation analysis models the system and signature uncertainties and sensitivities, whereas the simulation models the signatures and by extensive repetitions reveals the effect of errors in various reactor input or sensor response data. In the approach for the example presented, the errors accumulated by the signature (set of ''noise'' frequencies) are successively calculated as it is propagated stepwise through a system comprised of sensor and signal processing components. Additional modeling steps include a Fourier transform calculation to produce the usual power spectral density representation of the product signature, and some form of pattern recognition algorithm

  2. Sensor Interaction as a Source of the Electromagnetic Field Measurement Error

    Directory of Open Access Journals (Sweden)

    Hartansky R.

    2014-12-01

    Full Text Available The article deals with analytical calculation and numerical simulation of interactive influence of electromagnetic sensors. Sensors are components of field probe, whereby their interactive influence causes the measuring error. Electromagnetic field probe contains three mutually perpendicular spaced sensors in order to measure the vector of electrical field. Error of sensors is enumerated with dependence on interactive position of sensors. Based on that, proposed were recommendations for electromagnetic field probe construction to minimize the sensor interaction and measuring error.

  3. A flexible geospatial sensor observation service for diverse sensor data based on Web service

    Science.gov (United States)

    Chen, Nengcheng; Di, Liping; Yu, Genong; Min, Min

    Achieving a flexible and efficient geospatial Sensor Observation Service (SOS) is difficult, given the diversity of sensor networks, the heterogeneity of sensor data storage, and the differing requirements of users. This paper describes development of a service-oriented multi-purpose SOS framework. The goal is to create a single method of access to the data by integrating the sensor observation service with other Open Geospatial Consortium (OGC) services — Catalogue Service for the Web (CSW), Transactional Web Feature Service (WFS-T) and Transactional Web Coverage Service (WCS-T). The framework includes an extensible sensor data adapter, an OGC-compliant geospatial SOS, a geospatial catalogue service, a WFS-T, and a WCS-T for the SOS, and a geospatial sensor client. The extensible sensor data adapter finds, stores, and manages sensor data from live sensors, sensor models, and simulation systems. Abstract factory design patterns are used during design and implementation. A sensor observation service compatible with the SWE is designed, following the OGC "core" and "transaction" specifications. It is implemented using Java servlet technology. It can be easily deployed in any Java servlet container and automatically exposed for discovery using Web Service Description Language (WSDL). Interaction sequences between a Sensor Web data consumer and an SOS, between a producer and an SOS, and between an SOS and a CSW are described in detail. The framework has been successfully demonstrated in application scenarios for EO-1 observations, weather observations, and water height gauge observations.

  4. Wireless Sensor Node Power Profiling Based on IEEE 802.11 and IEEE 802.15.4 Communication Protocols. Modeling and Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Vivek [Idaho National Lab. (INL), Idaho Falls, ID (United States); Richardson, Joseph [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Yanliang [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-10-01

    Most wireless sensor network (comprising of thousands of WSNs) applications require operation over extended periods of time beginning with their deployment. Network lifetime is extremely critical for most applications and is one of the limiting factors for energy-constrained networks. Based on applications, there are wide ranges of different energy sources suitable for powering WSNs. A battery is traditionally used to power WSNs. The deployed WSN is required to last for long time. Due to finite amount of energy present in batteries, it is not feasible to replace batteries. Recently there has been a new surge in the area of energy harvesting were ambient energy in the environment can be utilized to prolong the lifetime of WSNs. Some of the sources of ambient energies are solar power, thermal gradient, human motion and body heat, vibrations, and ambient RF energy. The design and development of TEGs to power WSNs that would remain active for a long period of time requires comprehensive understanding of WSN operational. This motivates the research in modeling the lifetime, i.e., power consumption, of a WSN by taking into consideration various node and network level activities. A WSN must perform three essential tasks: sense events, perform quick local information processing of sensed events, and wirelessly exchange locally processed data with the base station or with other WSNs in the network. Each task has a power cost per unit tine and an additional cost when switching between tasks. There are number of other considerations that must also be taken into account when computing the power consumption associated with each task. The considerations includes: number of events occurring in a fixed active time period and the duration of each event, event-information processing time, total communication time, number of retransmission, etc. Additionally, at the network level the communication of information data packets between WSNs involves collisions, latency, and

  5. Hydrogen sensor

    Science.gov (United States)

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

    A hydrogen sensor for detecting/quantitating hydrogen and hydrogen isotopes includes a sampling line and a microplasma generator that excites hydrogen from a gas sample and produces light emission from excited hydrogen. A power supply provides power to the microplasma generator, and a spectrometer generates an emission spectrum from the light emission. A programmable computer is adapted for determining whether or not the gas sample includes hydrogen, and for quantitating the amount of hydrogen and/or hydrogen isotopes are present in the gas sample.

  6. Intrusion detection sensors

    International Nuclear Information System (INIS)

    Williams, J.D.

    1978-07-01

    Intrusion detection sensors are an integral part of most physical security systems. Under the sponsorship of the U.S. Department of Energy, Office of Safeguards and Security, Sandia Laboratories has conducted a survey of available intrusion detection sensors and has tested a number of different sensors. An overview of these sensors is provided. This overview includes (1) the operating principles of each type of sensor, (2) unique sensor characteristics, (3) desired sensor improvements which must be considered in planning an intrusion detection system, and (4) the site characteristics which affect the performance of both exterior and interior sensors. Techniques which have been developed to evaluate various intrusion detection sensors are also discussed

  7. Sensor Network Disposition Facing the Task of Multisensor Cross Cueing

    Directory of Open Access Journals (Sweden)

    Ce Pang

    2017-01-01

    Full Text Available In order to build the sensor network facing the task of multisensor crossing cueing, the requirements of initiating cueing and being cued are analyzed. Probability theory is used when building models, then probability of sensor cueing in the case of target moving is given, and, after that, the best distance between two sensors is calculated. The operational environment is described by normal distribution function. In the process of distributing sensor network, their elements, operational environment demand of cueing, and the probability of sensor network coverage are considered; then the optimization algorithm of sensor network based on hypothesis testing theory is made. The simulation result indicates that the algorithm can make sensor network which is required. On the basis of that, the two cases, including targets that make linear motion and orbit motion, are used to test the performance of the sensor network, which show that the sensor network can make uninterrupted detection on targets through multisensor cross cuing.

  8. Thermal sensors principles and applications for semiconductor industries

    CERN Document Server

    2015-01-01

    This book is a comprehensive guide to both the fundamentals of thermal sensors and their advanced functions. Key topics include sensor materials, CMOS-compatible sensors, measurement capabilities, thermal management and manufacturing processes. The introductory chapter covers the basic principles of thermal sensors from the essentials of heat transfer to smart wireless sensors. Later chapters illustrate the wide range of thermal sensor uses, from microprocessor thermal sensing to energy converter applications. Modeling and simulation techniques are used to explain the future direction of the field. Designed for researchers and practitioners working with wireless sensors and thermal management, Thermal Sensors: Principles and Applications for Semiconductor Industries is a valuable reference to the benefits and challenges these sensors offer. Advanced-level students studying mechanical or electrical engineering and networks will also find the content useful.

  9. Localization of a moving target using a fly eye sensor.

    Science.gov (United States)

    Khan, Arif; Streeter, Robert W; Wright, Cameron H G; Barrett, Steven F; Frost, Susan A

    2014-01-01

    An optical sensor based on the visual system of the common housefly (Musca domestica) has been developed by the researchers at the Wyoming Image and Signal Processing Research (WISPR) Laboratory. This optical sensor shows promising peformance for detection of an edge in real-time, with minimal processing overhead. An application of this sensor might be the deflection measurement of a moving target, such as the wing of an aircraft under test. In this paper, we have investiaged the possibility of localizing an edge, and hence the target, using the fly eye sensor, which is an important part of the deflection measurement process. A simulation program has been developed for this purpose, which simulates the sensor output, for a moving object on the target plane at a specified distance from the sensor. After successfully simulating the sensor output, it has been found that the location of an edge changes with the change in sensor to target distance, and their relative orientation. It also changes for the limited movement of the target, withing the field of view (FOV) of the sensor. On the contrary, the target-background contrast scenario, and shifting of the target normal to the target movement direction, do not affect the edge localization process. This paper shows and edge can be precisely detected for a target a aspecified distance from the sensor with proper sensor-target orientation, when the target moves all the way across the FOV of the sensor.

  10. Ingestible Sensors.

    Science.gov (United States)

    Kalantar-Zadeh, Kourosh; Ha, Nam; Ou, Jian Zhen; Berean, Kyle J

    2017-04-28

    Ingestible sensing capsules are fast emerging as a critical technology that has the ability to greatly impact health, nutrition, and clinical areas. These ingestible devices are noninvasive and hence are very attractive for customers. With widespread access to smart phones connected to the Internet, the data produced by this technology can be readily seen and reviewed online, and accessed by both users and physicians. The outputs provide invaluable information to reveal the state of gut health and disorders as well as the impact of food, medical supplements, and environmental changes on the gastrointestinal tract. One unique feature of such ingestible sensors is that their passage through the gut lumen gives them access to each individual organ of the gastrointestinal tract. Therefore, ingestible sensors offer the ability to gather images and monitor luminal fluid and the contents of each gut segment including electrolytes, enzymes, metabolites, hormones, and the microbial communities. As such, an incredible wealth of knowledge regarding the functionality and state of health of individuals through key gut biomarkers can be obtained. This Review presents an overview of the gut structure and discusses current and emerging digestible technologies. The text is an effort to provide a comprehensive overview of ingestible sensing capsules, from both a body physiology point of view as well as a technological view, and to detail the potential information that they can generate.

  11. Driving-Simulator-Based Test on the Effectiveness of Auditory Red-Light Running Vehicle Warning System Based on Time-To-Collision Sensor

    Directory of Open Access Journals (Sweden)

    Xuedong Yan

    2014-02-01

    Full Text Available The collision avoidance warning system is an emerging technology designed to assist drivers in avoiding red-light running (RLR collisions at intersections. The aim of this paper is to evaluate the effect of auditory warning information on collision avoidance behaviors in the RLR pre-crash scenarios and further to examine the casual relationships among the relevant factors. A driving-simulator-based experiment was designed and conducted with 50 participants. The data from the experiments were analyzed by approaches of ANOVA and structural equation modeling (SEM. The collisions avoidance related variables were measured in terms of brake reaction time (BRT, maximum deceleration and lane deviation in this study. It was found that the collision avoidance warning system can result in smaller collision rates compared to the without-warning condition and lead to shorter reaction times, larger maximum deceleration and less lane deviation. Furthermore, the SEM analysis illustrate that the audio warning information in fact has both direct and indirect effect on occurrence of collisions, and the indirect effect plays a more important role on collision avoidance than the direct effect. Essentially, the auditory warning information can assist drivers in detecting the RLR vehicles in a timely manner, thus providing drivers more adequate time and space to decelerate to avoid collisions with the conflicting vehicles.

  12. Optimal configuration of redundant inertial sensors for navigation and FDI performance.

    Science.gov (United States)

    Shim, Duk-Sun; Yang, Cheol-Kwan

    2010-01-01

    This paper considers the optimal sensor configuration for inertial navigation systems which have redundant inertial sensors such as gyroscopes and accelerometers. We suggest a method to determine the optimal sensor configuration which considers both the navigation and FDI performance. Monte Carlo simulations are performed to show the performance of the suggested optimal sensor configuration method.

  13. Sensor Data Security Level Estimation Scheme for Wireless Sensor Networks

    Science.gov (United States)

    Ramos, Alex; Filho, Raimir Holanda

    2015-01-01

    Due to their increasing dissemination, wireless sensor networks (WSNs) have become the target of more and more sophisticated attacks, even capable of circumventing both attack detection and prevention mechanisms. This may cause WSN users, who totally trust these security mechanisms, to think that a sensor reading is secure, even when an adversary has corrupted it. For that reason, a scheme capable of estimating the security level (SL) that these mechanisms provide to sensor data is needed, so that users can be aware of the actual security state of this data and can make better decisions on its use. However, existing security estimation schemes proposed for WSNs fully ignore detection mechanisms and analyze solely the security provided by prevention mechanisms. In this context, this work presents the sensor data security estimator (SDSE), a new comprehensive security estimation scheme for WSNs. SDSE is designed for estimating the sensor data security level based on security metrics that analyze both attack prevention and detection mechanisms. In order to validate our proposed scheme, we have carried out extensive simulations that show the high accuracy of SDSE estimates. PMID:25608215

  14. Sensor Data Security Level Estimation Scheme for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Alex Ramos

    2015-01-01

    Full Text Available Due to their increasing dissemination, wireless sensor networks (WSNs have become the target of more and more sophisticated attacks, even capable of circumventing both attack detection and prevention mechanisms. This may cause WSN users, who totally trust these security mechanisms, to think that a sensor reading is secure, even when an adversary has corrupted it. For that reason, a scheme capable of estimating the security level (SL that these mechanisms provide to sensor data is needed, so that users can be aware of the actual security state of this data and can make better decisions on its use. However, existing security estimation schemes proposed for WSNs fully ignore detection mechanisms and analyze solely the security provided by prevention mechanisms. In this context, this work presents the sensor data security estimator (SDSE, a new comprehensive security estimation scheme for WSNs. SDSE is designed for estimating the sensor data security level based on security metrics that analyze both attack prevention and detection mechanisms. In order to validate our proposed scheme, we have carried out extensive simulations that show the high accuracy of SDSE estimates.

  15. Sensor data security level estimation scheme for wireless sensor networks.

    Science.gov (United States)

    Ramos, Alex; Filho, Raimir Holanda

    2015-01-19

    Due to their increasing dissemination, wireless sensor networks (WSNs) have become the target of more and more sophisticated attacks, even capable of circumventing both attack detection and prevention mechanisms. This may cause WSN users, who totally trust these security mechanisms, to think that a sensor reading is secure, even when an adversary has corrupted it. For that reason, a scheme capable of estimating the security level (SL) that these mechanisms provide to sensor data is needed, so that users can be aware of the actual security state of this data and can make better decisions on its use. However, existing security estimation schemes proposed for WSNs fully ignore detection mechanisms and analyze solely the security provided by prevention mechanisms. In this context, this work presents the sensor data security estimator (SDSE), a new comprehensive security estimation scheme for WSNs. SDSE is designed for estimating the sensor data security level based on security metrics that analyze both attack prevention and detection mechanisms. In order to validate our proposed scheme, we have carried out extensive simulations that show the high accuracy of SDSE estimates.

  16. Object Georeferencing in UAV-Based SAR Terrain Images

    OpenAIRE

    Łabowski Michał; Kaniewski Piotr; Serafin Piotr; Wajszczyk Bronisław

    2016-01-01

    Synthetic aperture radars (SAR) allow to obtain high resolution terrain images comparable with the resolution of optical methods. Radar imaging is independent on the weather conditions and the daylight. The process of analysis of the SAR images consists primarily of identifying of interesting objects. The ability to determine their geographical coordinates can increase usability of the solution from a user point of view. The paper presents a georeferencing method of the radar terrain images. ...

  17. Assessing the geometric accuracy of UAV-based orthophotos ...

    African Journals Online (AJOL)

    In remote sensing and photogrammetric operations, the geometric quality of the imagery basically depends on the relation between pixel size and the map scale, contrast information, atmosphere and the sun elevation, the printing technology, screen resolution and the visual acuity. The Unmanned Aircraft System (UAS) ...

  18. Next Generation UAV Based Spectral Systems for Environmental Monitoring

    Data.gov (United States)

    National Aeronautics and Space Administration — At present, UAVs used in environmental monitoring mostly collect low spectral resolution imagery, capable of retrieving canopy greenness or properties related water...

  19. Uav-Based Automatic Tree Growth Measurement for Biomass Estimation

    Science.gov (United States)

    Karpina, M.; Jarząbek-Rychard, M.; Tymków, P.; Borkowski, A.

    2016-06-01

    Manual in-situ measurements of geometric tree parameters for the biomass volume estimation are time-consuming and economically non-effective. Photogrammetric techniques can be deployed in order to automate the measurement procedure. The purpose of the presented work is an automatic tree growth estimation based on Unmanned Aircraft Vehicle (UAV) imagery. The experiment was conducted in an agriculture test field with scots pine canopies. The data was collected using a Leica Aibotix X6V2 platform equipped with a Nikon D800 camera. Reference geometric parameters of selected sample plants were measured manually each week. In situ measurements were correlated with the UAV data acquisition. The correlation aimed at the investigation of optimal conditions for a flight and parameter settings for image acquisition. The collected images are processed in a state of the art tool resulting in a generation of dense 3D point clouds. The algorithm is developed in order to estimate geometric tree parameters from 3D points. Stem positions and tree tops are identified automatically in a cross section, followed by the calculation of tree heights. The automatically derived height values are compared to the reference measurements performed manually. The comparison allows for the evaluation of automatic growth estimation process. The accuracy achieved using UAV photogrammetry for tree heights estimation is about 5cm.

  20. Object Georeferencing in UAV-Based SAR Terrain Images

    Directory of Open Access Journals (Sweden)

    Łabowski Michał

    2016-12-01

    Full Text Available Synthetic aperture radars (SAR allow to obtain high resolution terrain images comparable with the resolution of optical methods. Radar imaging is independent on the weather conditions and the daylight. The process of analysis of the SAR images consists primarily of identifying of interesting objects. The ability to determine their geographical coordinates can increase usability of the solution from a user point of view. The paper presents a georeferencing method of the radar terrain images. The presented images were obtained from the SAR system installed on board an Unmanned Aerial Vehicle (UAV. The system was developed within a project under acronym WATSAR realized by the Military University of Technology and WB Electronics S.A. The source of the navigation data was an INS/GNSS system integrated by the Kalman filter with a feed-backward correction loop. The paper presents the terrain images obtained during flight tests and results of selected objects georeferencing with an assessment of the accuracy of the method.

  1. Assessing the geometric accuracy of UAV-based orthophotos

    African Journals Online (AJOL)

    DARAMOLA OLAGOKE

    Geometric quality. 1. Introduction. In Aerial photogrammetry, orthophotos, topographic maps and other map deliverables have been produced from the aerial photograph acquired ... relatively high and requires critical planning. ... mapping large area but the use of small format digital cameras has helped to achieve the same.

  2. Thermal Remote Sensing with Uav-Based Workflows

    Science.gov (United States)

    Boesch, R.

    2017-08-01

    Climate change will have a significant influence on vegetation health and growth. Predictions of higher mean summer temperatures and prolonged summer draughts may pose a threat to agriculture areas and forest canopies. Rising canopy temperatures can be an indicator of plant stress because of the closure of stomata and a decrease in the transpiration rate. Thermal cameras are available for decades, but still often used for single image analysis, only in oblique view manner or with visual evaluations of video sequences. Therefore remote sensing using a thermal camera can be an important data source to understand transpiration processes. Photogrammetric workflows allow to process thermal images similar to RGB data. But low spatial resolution of thermal cameras, significant optical distortion and typically low contrast require an adapted workflow. Temperature distribution in forest canopies is typically completely unknown and less distinct than for urban or industrial areas, where metal constructions and surfaces yield high contrast and sharp edge information. The aim of this paper is to investigate the influence of interior camera orientation, tie point matching and ground control points on the resulting accuracy of bundle adjustment and dense cloud generation with a typically used photogrammetric workflow for UAVbased thermal imagery in natural environments.

  3. UAV BASED BRDF-MEASUREMENTS OF AGRICULTURAL SURFACES WITH PFIFFIKUS

    Directory of Open Access Journals (Sweden)

    G. J. Grenzdörffer

    2012-09-01

    Full Text Available BRDF is a common problem in remote sensing and also in oblique photogrammetry. Common approaches of BRDF-measurement with a field goniometer are costly and rather cumbersome. UAVs may offer an interesting alternative by using a special flight pattern of oblique and converging images. The main part of this paper is the description of a photogrammetric workflow in order to determine the anisotropic reflection properties of a given surface. Due to the relatively low flying heights standard procedures from close range photogrammetry were adopted for outdoor usage. The photogrammetric processing delivered automatic and highly accurate orientation information with the aid of coded targets. The interior orientation of the consumer grade camera is more or less stable. The radiometrically corrected oblique images are converted into ortho photos. The azimuth and elevation angle of every point may then be computed. The calculated anisotropy of a winter wheat plot is shown. A system four diagonally-looking cameras (Four Vision and an additional nadir looking camera is under development. The multi camera system especially designed for a Micro- UAV with a payload of min 1 kg. The system is composed of five industrial digital frame cameras (1.3 Mpix CCD-chips, 15 fp/s with fixed lenses. Also special problems with the construction of a light weight housing of the multi camera solution are covered in the paper.

  4. 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.

  5. 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.

  6. Wireless Sensor Network for Forest Fire Detection

    Directory of Open Access Journals (Sweden)

    Emansa Hasri Putra

    2013-09-01

    Full Text Available Forest fires are one of problems that threaten sustainability of the forest. Early prevention system for indications of forest fires is absolutely necessary. The extent of the forest to be one of the problems encountered in the forest condition monitoring. To overcome the problems of forest extent, designed a system of forest fire detection system by adopting the Wireless Sensor Network (WSN using multiple sensor nodes. Each sensor node has a microcontroller, transmitter/receiver and three sensors. Measurement method is performed by measuring the temperature, flame, the levels of methane, hydrocarbons, and CO2 in some forest area and the combustion of peat in a simulator. From results of measurements of temperature, levels of methane, a hydrocarbon gas and CO2 in an open area indicates there are no signs of fires due to the value of the temperature, methane, hydrocarbon gas, and CO2 is below the measurement in the space simulator.

  7. Minimum Energy Decentralized Estimation in a Wireless Sensor Network with Correlated Sensor Noises

    Directory of Open Access Journals (Sweden)

    Krasnopeev Alexey

    2005-01-01

    Full Text Available Consider the problem of estimating an unknown parameter by a sensor network with a fusion center (FC. Sensor observations are corrupted by additive noises with an arbitrary spatial correlation. Due to bandwidth and energy limitation, each sensor is only able to transmit a finite number of bits to the FC, while the latter must combine the received bits to estimate the unknown parameter. We require the decentralized estimator to have a mean-squared error ( that is within a constant factor to that of the best linear unbiased estimator (BLUE. We minimize the total sensor transmitted energy by selecting sensor quantization levels using the knowledge of noise covariance matrix while meeting the target requirement. Computer simulations show that our designs can achieve energy savings up to when compared to the uniform quantization strategy whereby each sensor generates the same number of bits, irrespective of the quality of its observation and the condition of its channel to the FC.

  8. MEMS wireless temperature sensor for combustion studies

    Science.gov (United States)

    Lee, Minhyeok; Kawahara, Yoshihiro; Morimoto, Kenichi; Suzuki, Yuji

    2014-11-01

    A MEMS wireless wall temperature sensor for combustion studies is proposed. Electrical resistance change in a LCR circuit is used to measure the temperature through inductive coupling the sensor coil and the read-out coil. Equivalent circuit model and 3-D electromagnetic simulation are employed to design sensor configuration. The resonant frequency is increased with increasing the resistance due to the temperature increase. The prototype sensor was successfully fabricated with MEMS technologies. The impedance phase angle shows a sharp dip at the resonant frequency, which is in good accordance with the equivalent circuit model. The measured temperature sensitivity is found to be as high as 6 kHz/K, when the distance between the read-out and the sensor coils is 0.71 mm.

  9. A carbon nanotube-based pressure sensor

    Science.gov (United States)

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

    2011-06-01

    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.

  10. On-skin liquid metal inertial sensor.

    Science.gov (United States)

    Varga, Matija; Ladd, Collin; Ma, Siyuan; Holbery, Jim; Tröster, Gerhard

    2017-09-26

    A wireless on-skin inertial sensor based on free-moving liquid metal is introduced. The inertial sensor comprises a eutectic gallium-indium (eGaIn) droplet that modulates the capacitance between two electrodes. The capacitive output of the sensor is connected to a planar coil to form an LC resonator whose resonant frequency can be read out wirelessly. Liquid metal electrodes and the coil are fabricated on a 20 μm thick silicone membrane, which can stretch up to 600%, using spray-deposition of eGaIn. The moving droplet is encapsulated on the opposite side of the membrane using spray-deposition of Dragon Skin 10 silicone. The output characteristics, electrical simulations of the capacitance, and dynamic characteristics of the sensor are shown. The sensor is used for measuring tilt angles and recording arm gestures.

  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. System-level Modeling of Wireless Integrated Sensor Networks

    DEFF Research Database (Denmark)

    Virk, Kashif M.; Hansen, Knud; Madsen, Jan

    2005-01-01

    Wireless integrated sensor networks have emerged as a promising infrastructure for a new generation of monitoring and tracking applications. In order to efficiently utilize the extremely limited resources of wireless sensor nodes, accurate modeling of the key aspects of wireless sensor networks...... is necessary so that system-level design decisions can be made about the hardware and the software (applications and real-time operating system) architecture of sensor nodes. In this paper, we present a SystemC-based abstract modeling framework that enables system-level modeling of sensor network behavior...... by modeling the applications, real-time operating system, sensors, processor, and radio transceiver at the sensor node level and environmental phenomena, including radio signal propagation, at the sensor network level. We demonstrate the potential of our modeling framework by simulating and analyzing a small...

  13. Scaling Laws for NanoFET Sensors

    OpenAIRE

    Zhou, Fu-Shan; Wei, Qi-Huo

    2007-01-01

    The sensitive conductance change of semiconductor nanowires and carbon nanotubes in response to binding of charged molecules provide a novel sensing modality which is generally denoted as nanoFET sensors. In this paper, we study the scaling laws of nanoplate FET sensors by simplifying nanoplates as random resistor networks with molecular receptors sitting on lattice sites. Nanowire/tube FETs are included as the limiting cases where the device width goes small. Computer simulations show that t...

  14. EDITORIAL: Humidity sensors Humidity sensors

    Science.gov (United States)

    Regtien, Paul P. L.

    2012-01-01

    produced at relatively low cost. Therefore, they find wide use in lots of applications. However, the method requires a material that possesses some conflicting properties: stable and reproducible relations between air humidity, moisture uptake and a specific property (for instance the length of a hair, the electrical impedance of the material), fast absorption and desorption of the water vapour (to obtain a short response time), small hysteresis, wide range of relative humidity (RH) and temperature-independent output (only responsive to RH). For these reasons, much research is done and is still going on to find suitable materials that combine high performance and low price. In this special feature, three of the four papers report on absorption sensors, all with different focus. Aziz et al describe experiments with newly developed materials. The surface structure is extensively studied, in view of its ability to rapidly absorb water vapour and exhibit a reproducible change in the resistance and capacitance of the device. Sanchez et al employ optical fibres coated with a thin moisture-absorbing layer as a sensitive humidity sensor. They have studied various coating materials and investigated the possibility of using changes in optical properties of the fibre (here the lossy mode resonance) due to a change in humidity of the surrounding air. The third paper, by Weremczuk et al, focuses on a cheap fabrication method for absorption-based humidity sensors. The inkjet technology appears to be suitable for mass fabrication of such sensors, which is demonstrated by extensive measurements of the electrical properties (resistance and capacitance) of the absorbing layers. Moreover, they have developed a model that describes the relation between humidity and the electrical parameters of the moisture-sensitive layer. Despite intensive research, absorption sensors still do not meet the requirements for high accuracy applications. The dew-point temperature method is more appropriate

  15. Sensor fault detection and recovery in satellite attitude control

    Science.gov (United States)

    Nasrolahi, Seiied Saeed; Abdollahi, Farzaneh

    2018-04-01

    This paper proposes an integrated sensor fault detection and recovery for the satellite attitude control system. By introducing a nonlinear observer, the healthy sensor measurements are provided. Considering attitude dynamics and kinematic, a novel observer is developed to detect the fault in angular rate as well as attitude sensors individually or simultaneously. There is no limit on type and configuration of attitude sensors. By designing a state feedback based control signal and Lyapunov stability criterion, the uniformly ultimately boundedness of tracking errors in the presence of sensor faults is guaranteed. Finally, simulation results are presented to illustrate the performance of the integrated scheme.

  16. Thermal luminescence spectroscopy chemical imaging sensor.

    Science.gov (United States)

    Carrieri, Arthur H; Buican, Tudor N; Roese, Erik S; Sutter, James; Samuels, Alan C

    2012-10-01

    The authors present a pseudo-active chemical imaging sensor model embodying irradiative transient heating, temperature nonequilibrium thermal luminescence spectroscopy, differential hyperspectral imaging, and artificial neural network technologies integrated together. We elaborate on various optimizations, simulations, and animations of the integrated sensor design and apply it to the terrestrial chemical contamination problem, where the interstitial contaminant compounds of detection interest (analytes) comprise liquid chemical warfare agents, their various derivative condensed phase compounds, and other material of a life-threatening nature. The sensor must measure and process a dynamic pattern of absorptive-emissive middle infrared molecular signature spectra of subject analytes to perform its chemical imaging and standoff detection functions successfully.

  17. Optical beam deflection sensor: design and experiments.

    Science.gov (United States)

    Sakamoto, João M S; Marques, Renan B; Kitano, Cláudio; Rodrigues, Nicolau A S; Riva, Rudimar

    2017-10-01

    In this work, we present a double-pass optical beam deflection sensor and its optical design method. To accomplish that, a mathematical model was proposed and computational simulations were performed, in order to obtain the sensor's characteristic curves and to analyze its behavior as function of design parameters. The mathematical model was validated by comparison with the characteristic curves acquired experimentally. The sensor was employed to detect acoustic pulses generated by a pulsed laser in a sample surface, in order to show its potential for monitoring applications handling high energy input as laser welding or laser ablation.

  18. Allegany Ballistics Lab: sensor test target system

    Science.gov (United States)

    Eaton, Deran S.

    2011-06-01

    Leveraging the Naval Surface Warfare Center, Indian Head Division's historical experience in weapon simulation, Naval Sea Systems Command commissioned development of a remote-controlled, digitally programmable Sensor Test Target as part of a modern, outdoor hardware-in-the-loop test system for ordnance-related guidance, navigation and control systems. The overall Target system design invokes a sciences-based, "design of automated experiments" approach meant to close the logistical distance between sensor engineering and developmental T&E in outdoor conditions over useful real world distances. This enables operating modes that employ broad spectrum electromagnetic energy in many a desired combination, variably generated using a Jet Engine Simulator, a multispectral infrared emitter array, optically enhanced incandescent Flare Simulators, Emitter/Detector mounts, and an RF corner reflector kit. As assembled, the recently tested Sensor Test Target prototype being presented can capably provide a full array of useful RF and infrared target source simulations for RDT&E use with developmental and existing sensors. Certain Target technologies are patent pending, with potential spinoffs in aviation, metallurgy and biofuels processing, while others are variations on well-established technology. The Sensor Test Target System is planned for extended installation at Allegany Ballistics Laboratory (Rocket Center, WV).

  19. Simulation of Quantum Phenomena in Nanowire Sensors

    Science.gov (United States)

    2014-12-17

    Advisory Commission of the UNESCO -UNISA Africa Chair in Nanosciences/Nanotechnology, University of South Africa, Pretoria...Italy 2013 Appointed Member of Advisory Commission of the UNESCO -UNISA Africa Chair in Nanosciences/Nanotechnology

  20. Sensors an introductory course

    CERN Document Server

    Kalantar-zadeh, Kourosh

    2013-01-01

    Sensors: An Introductory Course provides an essential reference on the fundamentals of sensors. The book is designed to help readers in developing skills and the understanding required in order to implement a wide range of sensors that are commonly used in our daily lives. This book covers the basic concepts in the sensors field, including definitions and terminologies. The physical sensing effects are described, and devices which utilize these effects are presented. The most frequently used organic and inorganic sensors are introduced and the techniques for implementing them are discussed. This book: Provides a comprehensive representation of the most common sensors and can be used as a reference in relevant fields Presents learning materials in a concise and easy to understand manner Includes examples of how sensors are incorporated in real life measurements Contains detailed figures and schematics to assist in understanding the sensor performance Sensors: An Introductory Course is ideal for university stu...

  1. Smart Optoelectronic Sensors and Intelligent Sensor Systems

    Directory of Open Access Journals (Sweden)

    Sergey Y. YURISH

    2012-03-01

    Full Text Available Light-to-frequency converters are widely used in various optoelectronic sensor systems. However, a further frequency-to-digital conversion is a bottleneck in such systems due to a broad frequency range of light-to-frequency converters’ outputs. This paper describes an effective OEM design approach, which can be used for smart and intelligent sensor systems design. The design is based on novel, multifunctional integrated circuit of Universal Sensors & Transducers Interface especially designed for such sensor applications. Experimental results have confirmed an efficiency of this approach and high metrological performances.

  2. EMPLOYING SENSOR NETWORK TO GUIDE FIREFIGHTERS IN DANGEROUS AREA

    DEFF Research Database (Denmark)

    Koohi, Hamidreza; Nadernejad, Ehsan; Fathi, Mahmoud

    2010-01-01

    In this paper, we intend to focus on the sensor network applications in firefighting. A distributed algorithm is developed for the sensor network to guide firefighters through a burning area. The sensor network models the danger of the area under coverage as obstacles, and has the property to adapt...... itself against possible changes. The protocol developed, will integrate the artificial potential field of the sensors with the information of the intended place of moving firefighter so that it guides the firefighter step by step through the sensor network by choosing the safest path in dangerous zones....... This protocol is simulated by Visual-Sense and the simulation results are available. Keyword: Firefighter, Sensor Network, Potential Field, Area’s Danger, Navigation...

  3. A Nodes Deployment Algorithm in Wireless Sensor Network Based on Distribution

    Directory of Open Access Journals (Sweden)

    Song Yuli

    2014-07-01

    Full Text Available Wireless sensor network coverage is a basic problem of wireless sensor network. In this paper, we propose a wireless sensor network node deployment algorithm base on distribution in order to form an efficient wireless sensor network. The iteratively greedy algorithm is used in this paper to choose priority nodes into active until the entire network is covered by wireless sensor nodes, the whole network to multiply connected. The simulation results show that the distributed wireless sensor network node deployment algorithm can form a multiply connected wireless sensor network.

  4. Low cost Earth attitude sensor

    Science.gov (United States)

    Liberati, Fabrizio; Perrotta, Giorgio; Verzegnassi, Fulvia

    2017-11-01

    A patent-pending, low-cost, moderate performance, Earth Attitude Sensor for LEO satellites is described in this paper. The paper deals with the system concepts, the technology adopted and the simulation results. The sensor comprises three or four narrow field of view mini telescopes pointed towards the Earth edge to detect and measure the variation of the off-nadir angle of the Earth-to-black sky transition using thermopile detectors suitably placed in the foci of the optical min telescopes. The system's innovation consists in the opto-mechanical configuration adopted that is sturdy and has no moving parts being , thus, inherently reliable. In addition, with a view to reducing production costs, the sensor does without hi-rel and is instead mainly based on COTS parts suitably chosen. Besides it is flexible and can be adapted to perform attitude measurement onboard spacecraft flying in orbits other than LEO with a minimum of modifications to the basic design. At present the sensor is under development by IMT and OptoService.

  5. Towards Sensor Database Systems

    DEFF Research Database (Denmark)

    Bonnet, Philippe; Gehrke, Johannes; Seshadri, Praveen

    2001-01-01

    . These systems lack flexibility because data is extracted in a predefined way; also, they do not scale to a large number of devices because large volumes of raw data are transferred regardless of the queries that are submitted. In our new concept of sensor database system, queries dictate which data is extracted...... from the sensors. In this paper, we define the concept of sensor databases mixing stored data represented as relations and sensor data represented as time series. Each long-running query formulated over a sensor database defines a persistent view, which is maintained during a given time interval. We...... also describe the design and implementation of the COUGAR sensor database system....

  6. 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.

  7. Design of Micro-Ice Detection Sensor for Aerospace Application

    OpenAIRE

    Sayali Pol; Yashwant Adhav

    2013-01-01

    MEMS (Micro Electro Mechanical System) design systems are used for the development of Micro Ice Detection Sensors, which give change in capacitance as output when ice is detected on aircraft body. Ice detection technique using Silicon diaphragm as sensing element by using Intellisuit is presented. The capacitive technique for ice detection is used. Finite element analysis (FEA) is done to optimize the sensor geometry for enhanced sensitivity to ice accretion. The sensor is simulated in 2 mod...

  8. Development of an acoustic sensor for a geothermal Borehole Televiewer

    Energy Technology Data Exchange (ETDEWEB)

    Wonn, J.W.

    1979-03-01

    The objective of this project is to upgrade acoustic sensor technology such that appropriate well logging instruments can be made to operate under the hostile environment conditions anticipated in geothermal resource exploration and evaluation. The Borehole Televiewer (BHTV) was selected as the vehicle for this sensor improvement work, primarily because of its demonstrated ability to detect and characterize fractures under sub-geothermal conditions. The work done toward providing an improved sensor for the televiewer is described. An experimental sensor concept was devised, incorporating a thin metal acoustic window, an improved, high-temperature internal coupling fluid, and thermally resistant sensor internals. During an autoclave test, it was successfully demonstrated that the resulting experimental sensor design concept provides the basic target detection and characterization functions required of a fracture mapping, Borehole Televiewer under simulated geothermal conditions. In particular, the experimental sensor remained operational at 275/sup 0/C and 7000 psi.

  9. Development of an acoustic sensor for a geothermal borehole televiewer

    Energy Technology Data Exchange (ETDEWEB)

    Wonn, J.W.

    1979-03-01

    The objective of this project is to upgrade acoustic sensor technology such that appropriate well logging instruments can be made to operate under the hostile environment conditions anticipated in geothermal resource exploration and evaluation. The Borehole Televiewer (BHTV) was selected as the vehicle for this sensor improvement work, primarily because of its demonstrated ability to detect and characterize fractures under sub-geothermal conditions. The work done toward providing an improved sensor for the televiewer is described. An experimental sensor concept was devised, incorporating a thin metal acoustic window, an improved, high-temperature internal coupling fluid, and thermally resistant sensor internals. During an autoclave test, it was successfully demonstrated that the resulting experimental sensor design concept provides the basic target detection and characterization functions required of a fracture mapping, Borehole Televiewer under simulated geothermal conditions. In particular, the experimental sensor remained operational at 275/sup 0/C and 7000 psi.

  10. Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors

    Directory of Open Access Journals (Sweden)

    Ivan Felis

    2016-06-01

    Full Text Available Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. With the aim of optimizing the sensor system, a test bench for the characterization of the sensors has been developed. The sensor response for different piezoelectric materials, geometries, matching layers, and backing layers have been measured and contrasted with FEM simulations and analytical models. The results of these studies lead us to have a design criterion for the construction of specific sensors for the next generation of dark matter bubble chamber detectors (250 L.

  11. Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors.

    Science.gov (United States)

    Felis, Ivan; Martínez-Mora, Juan Antonio; Ardid, Miguel

    2016-06-10

    Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. With the aim of optimizing the sensor system, a test bench for the characterization of the sensors has been developed. The sensor response for different piezoelectric materials, geometries, matching layers, and backing layers have been measured and contrasted with FEM simulations and analytical models. The results of these studies lead us to have a design criterion for the construction of specific sensors for the next generation of dark matter bubble chamber detectors (250 L).

  12. Infrared sensors and sensor fusion; Proceedings of the Meeting, Orlando, FL, May 19-21, 1987

    International Nuclear Information System (INIS)

    Buser, R.G.; Warren, F.B.

    1987-01-01

    The present conference discusses topics in the fields of IR sensor multifunctional design; image modeling, simulation, and detection; IR sensor configurations and components; thermal sensor arrays; silicide-based IR sensors; and IR focal plane array utilization. Attention is given to the fusion of lidar and FLIR for target segmentation and enhancement, the synergetic integration of thermal and visual images for computer vision, the 'Falcon Eye' FLIR system, multifunctional electrooptics and multiaperture sensors for precision-guided munitions, and AI approaches to data integration. Also discussed are the comparative performance of Ir silicide and Pt silicide photodiodes, high fill-factor silicide monolithic arrays, and the characterization of noise in staring IR focal plane arrays

  13. Invisible magnetic sensors

    Science.gov (United States)

    Mach-Batlle, Rosa; Navau, Carles; Sanchez, Alvaro

    2018-04-01

    Sensing magnetic fields is essential in many applications in biomedicine, transportation, or smart cities. The distortion magnetic sensors create in response to the field they are detecting may hinder their use, for example, in applications requiring dense packaging of sensors or accurately shaped field distributions. For sensing electromagnetic waves, cloaking shells that reduce the scattering of sensors have been introduced. However, the problem of making a magnetic sensor undetectable remains unsolved. Here, we present a general strategy on how to make a sensor magnetically invisible while keeping its ability to sense. The sensor is rendered undetectable by surrounding it with a spherical shell having a tailored magnetic permeability. Our method can be applied to arbitrary shaped magnetic sensors in arbitrary magnetic fields. The invisibility can be made exact when the sensor is spherical and the probed field is uniform. A metasurface composed of superconducting pieces is presented as a practical realization of the ideal invisibility shell.

  14. Electrochemical Sensors: Functionalized Silica

    Energy Technology Data Exchange (ETDEWEB)

    Fryxell, Glen E.; Lin, Yuehe; Yantasee, Wassana

    2009-03-24

    This chapter summarizes recent devellopment of electrochemical sensors based on functionlized mesoporous silica materials. The nanomatrials based sensors have been developed for sensitive and selective enrironmental detection of toxic heavy metal and uranium ions.

  15. Towards Sensor Database Systems

    DEFF Research Database (Denmark)

    Bonnet, Philippe; Gehrke, Johannes; Seshadri, Praveen

    2001-01-01

    Sensor networks are being widely deployed for measurement, detection and surveillance applications. In these new applications, users issue long-running queries over a combination of stored data and sensor data. Most existing applications rely on a centralized system for collecting sensor data....... These systems lack flexibility because data is extracted in a predefined way; also, they do not scale to a large number of devices because large volumes of raw data are transferred regardless of the queries that are submitted. In our new concept of sensor database system, queries dictate which data is extracted...... from the sensors. In this paper, we define the concept of sensor databases mixing stored data represented as relations and sensor data represented as time series. Each long-running query formulated over a sensor database defines a persistent view, which is maintained during a given time interval. We...

  16. Embedded sensor systems

    CERN Document Server

    Agrawal, Dharma Prakash

    2017-01-01

    This inspiring textbook provides an introduction to wireless technologies for sensors, explores potential use of sensors for numerous applications, and utilizes probability theory and mathematical methods as a means of embedding sensors in system design. It discusses the need for synchronization and underlying limitations, inter-relation between given coverage and connectivity to number of sensors needed, and the use of geometrical distance to determine location of the base station for data collection and explore use of anchor nodes for relative position determination of sensors. The book explores energy conservation, communication using TCP, the need for clustering and data aggregation, and residual energy determination and energy harvesting. It covers key topics of sensor communication like mobile base stations and relay nodes, delay-tolerant sensor networks, and remote sensing and possible applications. The book defines routing methods and do performance evaluation for random and regular sensor topology an...

  17. Air Sensor Toolbox

    Science.gov (United States)

    Air Sensor Toolbox provides information to citizen scientists, researchers and developers interested in learning more about new lower-cost compact air sensor technologies and tools for measuring air quality.

  18. Sensor Substrate Development

    Data.gov (United States)

    National Aeronautics and Space Administration — Novel substrates, such as aerogels and porous, low density ceramics may increase the sensitivities of chemical reaction-based sensors for toxic vapors. These sensors...

  19. Micro-electro-mechanical system (MEMS)-based fiber optic sensor and sensor network for improving weapon stabilization and fire control

    Science.gov (United States)

    Zhang, Sean Z.; Xu, Guoda; Qiu, Wei; Lin, Freddie S.; Testa, Robert C.; Mattice, Michael S.

    2000-08-01

    A MicroElectroMechanical Systems (MEMS)-based fiber optic sensor and sensor network for improving weapon stabilization and fire control have been developed. Fabrication involves overwriting two fiber Bragg gratings (FBGs) onto a polarization-preserving optical fiber core. A MEMS diaphragm is fabricated and integrated with the overlaid FBGs to enhance the performance and reliability of the sensor. A simulation model for the MEMS fiber optic sensor and sensor network has been derived, and simulation results concerning load, angle, strain, and temperature have been obtained. The fabricated MEMS diaphragm and the overlaid FBGs have been packaged together on the basis of simulation results and mounted on a specially designed cantilever system. The combined multifunctional MEMS fiber optic sensor and sensor network is cost-effective, fast, rugged enough to operate in harsh environmental conditions, compact, and highly sensitive.

  20. Cantilever surface stress sensors with single-crystalline silicon piezoresistors

    DEFF Research Database (Denmark)

    Rasmussen, Peter Andreas; Hansen, Ole; Boisen, Anja

    2005-01-01

    on cantilever sensors with integrated piezoresistive readout, that one finds between typical atomic force microscopy measurements and the surface stress sensors used in, e.g., biochemical measurements. We have simulated the response from piezoresistive cantilevers as a function of resistor type and placement...

  1. Building battlefield sensor environments with the VIEWS Workbench

    Energy Technology Data Exchange (ETDEWEB)

    Hield, C.W.; Christiansen, J.H.; Simunich, K.L.; Woyna, M.A.

    1993-08-01

    The visual Intelligence and Electronic Warfare Simulation (VIEWS) Workbench software system has been developed by Argonne National Laboratory to enable Army intelligence and electronic warfare (IEW) analysts at (UNIX) workstations to conveniently build detailed IEW battlefield scenarios, or ``sensor environments,`` to drive the Army`s high-resolution IEW sensor performance models. Views is fully object-oriented, including the underlying database.

  2. Digital Sensor Technology

    Energy Technology Data Exchange (ETDEWEB)

    Ted Quinn; Jerry Mauck; Richard Bockhorst; Ken Thomas

    2013-07-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy, reliability, availability, and maintainability. This report demonstrates these benefits in direct comparisons of digital and analog sensor applications. It also addresses the qualification issues that must be addressed in the application of digital sensor technology.

  3. Emergent Behavior in Massively-Deployed Sensor Networks

    Directory of Open Access Journals (Sweden)

    Ekaterina Shurkova

    2008-01-01

    Full Text Available The phenomenal advances in MEMS and nanotechnology make it feasible to build small devices, referred to as sensors that are able to sense, compute and communicate over small distances. The massive deployment of these small devices raises the fascinating question of whether or not the sensors, as a collectivity, will display emergent behavior, just as living organisms do. In this work we report on a recent effort intended to observe emerging behavior of large groups of sensor nodes, like living cells demonstrate. Imagine a massive deployment of sensors that can be in two states "red" and "blue". At deployment time individual sensors have an initial color. The goal is to obtain a uniform coloring of the deployment area. Importantly, the sensors can only talk to sensors that are one-hop away from them. The decisions to change colors are local, based on what the sensors can infer from collecting color information from their neighbors. We have performed extensive simulations involving 20,000 sensors in an area of 100 m × 100 m. Our simulation results show that the sensor network converges to a stable uniform coloring extremely fast.

  4. Multi-Sensor Architectures

    DEFF Research Database (Denmark)

    Hussain, Dil Muhammad Akbar; Ahmed, Zaki; Khan, M. Z.

    2012-01-01

    The use of multiple sensors typically requires the fusion of data from different type of sensors. The combined use of such a data has the potential to give an efficient, high quality and reliable estimation. Input data from different sensors allows the introduction of target attributes (target ty...

  5. Laser sensor system documentation.

    Science.gov (United States)

    2017-03-01

    Phase 1 of TxDOT Project 0-6873, True Road Surface Deflection Measuring Device, developed a : laser sensor system based on several sensors mounted on a rigid beam. : This sensor system remains with CTR currently, as the project is moving into Phase 2...

  6. Sensor readout detector circuit

    Science.gov (United States)

    Chu, D.D.; Thelen, D.C. Jr.

    1998-08-11

    A sensor readout detector circuit is disclosed that is capable of detecting sensor signals down to a few nanoamperes or less in a high (microampere) background noise level. The circuit operates at a very low standby power level and is triggerable by a sensor event signal that is above a predetermined threshold level. A plurality of sensor readout detector circuits can be formed on a substrate as an integrated circuit (IC). These circuits can operate to process data from an array of sensors in parallel, with only data from active sensors being processed for digitization and analysis. This allows the IC to operate at a low power level with a high data throughput for the active sensors. The circuit may be used with many different types of sensors, including photodetectors, capacitance sensors, chemically-sensitive sensors or combinations thereof to provide a capability for recording transient events or for recording data for a predetermined period of time following an event trigger. The sensor readout detector circuit has applications for portable or satellite-based sensor systems. 6 figs.

  7. Focus on image sensors

    NARCIS (Netherlands)

    Jos Gunsing; Daniël Telgen; Johan van Althuis; Jaap van de Loosdrecht; Mark Stappers; Peter Klijn

    2013-01-01

    Robots need sensors to operate properly. Using a single image sensor, various aspects of a robot operating in its environment can be measured or monitored. Over the past few years, image sensors have improved a lot: frame rate and resolution have increased, while prices have fallen. As a result,

  8. 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

  9. Sensors and actuators, Twente

    NARCIS (Netherlands)

    Bergveld, Piet

    1989-01-01

    This paper describes the organization and the research programme of the Sensor and Actuator (S&A) Research Unit of the University of Twente, Enschede, the Netherlands. It includes short descriptions of all present projects concerning: micromachined mechanical sensors and actuators, optical sensors,

  10. Thermal flow micro sensors

    NARCIS (Netherlands)

    Elwenspoek, Michael Curt

    1999-01-01

    A review is given on sensors fabricated by silicon micromachining technology using the thermal domain for the measurement of fluid flow. Attention is paid especially to performance and geometry of the sensors. Three basic types of thermal flow sensors are discussed: anemometers, calorimetric flow

  11. Sensors for Entertainment

    Directory of Open Access Journals (Sweden)

    Fabrizio Lamberti

    2016-07-01

    Full Text Available Sensors are becoming ubiquitous in all areas of science, technology, and society. In this Special Issue on “Sensors for Entertainment”, developments in progress and the current state of application scenarios for sensors in the field of entertainment is explored.

  12. High temperature sensor

    Science.gov (United States)

    Tokarz, Richard D.

    1982-01-01

    A high temperature sensor includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range (1,000 to 2,000 K.). When required, the sensor can be encased within a ceramic protective coating.

  13. Automotive vehicle sensors

    Energy Technology Data Exchange (ETDEWEB)

    Sheen, S.H.; Raptis, A.C.; Moscynski, M.J.

    1995-09-01

    This report is an introduction to the field of automotive vehicle sensors. It contains a prototype data base for companies working in automotive vehicle sensors, as well as a prototype data base for automotive vehicle sensors. A market analysis is also included.

  14. Optimization of autonomous magnetic field sensor consisting of giant magnetoimpedance sensor and surface acoustic wave transducer

    KAUST Repository

    Li, Bodong

    2012-11-01

    This paper presents a novel autonomous thin film magnetic field sensor consisting of a tri-layer giant magnetoimpedance sensor and a surface acoustic wave transponder. Double and single electrode interdigital transducer (IDT) designs are employed and compared. The integrated sensor is fabricated using standard microfabrication technology. The results show the double electrode IDT has an advantage in terms of the sensitivity. In order to optimize the matching component, a simulation based on P-matrix is carried out. A maximum change of 2.4 dB of the reflection amplitude and a sensitivity of 0.34 dB/Oe are obtained experimentally. © 2012 IEEE.

  15. Micromachined High-Temperature Sensors for Planet Exploration, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In phase I of the SBIR program, LEEOAT Company will develop, simulate, fabricate and test high-temperature piezoelectric miniature sensors (up to 800oC), for...

  16. Virtual Sensor Test Instrumentation

    Science.gov (United States)

    Wang, Roy

    2011-01-01

    Virtual Sensor Test Instrumentation is based on the concept of smart sensor technology for testing with intelligence needed to perform sell-diagnosis of health, and to participate in a hierarchy of health determination at sensor, process, and system levels. A virtual sensor test instrumentation consists of five elements: (1) a common sensor interface, (2) microprocessor, (3) wireless interface, (4) signal conditioning and ADC/DAC (analog-to-digital conversion/ digital-to-analog conversion), and (5) onboard EEPROM (electrically erasable programmable read-only memory) for metadata storage and executable software to create powerful, scalable, reconfigurable, and reliable embedded and distributed test instruments. In order to maximize the efficient data conversion through the smart sensor node, plug-and-play functionality is required to interface with traditional sensors to enhance their identity and capabilities for data processing and communications. Virtual sensor test instrumentation can be accessible wirelessly via a Network Capable Application Processor (NCAP) or a Smart Transducer Interlace Module (STIM) that may be managed under real-time rule engines for mission-critical applications. The transducer senses the physical quantity being measured and converts it into an electrical signal. The signal is fed to an A/D converter, and is ready for use by the processor to execute functional transformation based on the sensor characteristics stored in a Transducer Electronic Data Sheet (TEDS). Virtual sensor test instrumentation is built upon an open-system architecture with standardized protocol modules/stacks to interface with industry standards and commonly used software. One major benefit for deploying the virtual sensor test instrumentation is the ability, through a plug-and-play common interface, to convert raw sensor data in either analog or digital form, to an IEEE 1451 standard-based smart sensor, which has instructions to program sensors for a wide variety of

  17. Positioning system in wireless sensor networks using NS-2

    CSIR Research Space (South Africa)

    Abu-Mahfouz, Adnan M

    2012-10-01

    Full Text Available and techniques require that the positions of the sensor nodes be determined. Localisation algorithms (e.g.[1-5]) follow several approaches to estimate positions of sensor nodes. One approach is to use special nodes, called beacons, which know their own... and analysing its performance have made simulation essential for the study of WSNs. Simulation is widely used in system modelling for applications ranging from engineering research, business analysis, manufacturing planning and biological science...

  18. Multifuctional integrated sensors (MFISES).

    Energy Technology Data Exchange (ETDEWEB)

    Homeijer, Brian D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roozeboom, Clifton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-10-01

    Many emerging IoT applications require sensing of multiple physical and environmental parameters for: completeness of information, measurement validation, unexpected demands, improved performance. For example, a typical outdoor weather station measures temperature, humidity, barometric pressure, light intensity, rainfall, wind speed and direction. Existing sensor technologies do not directly address the demand for cost, size, and power reduction in multi-paramater sensing applications. Industry sensor manufacturers have developed integrated sensor systems for inertial measurements that combine accelerometers, gyroscopes, and magnetometers, but do not address environmental sensing functionality. In existing research literature, a technology gap exists between the functionality of MEMS sensors and the real world applications of the sensors systems.

  19. Sensor mount assemblies and sensor assemblies

    Science.gov (United States)

    Miller, David H [Redondo Beach, CA

    2012-04-10

    Sensor mount assemblies and sensor assemblies are provided. In an embodiment, by way of example only, a sensor mount assembly includes a busbar, a main body, a backing surface, and a first finger. The busbar has a first end and a second end. The main body is overmolded onto the busbar. The backing surface extends radially outwardly relative to the main body. The first finger extends axially from the backing surface, and the first finger has a first end, a second end, and a tooth. The first end of the first finger is disposed on the backing surface, and the tooth is formed on the second end of the first finger.

  20. Distributed model-based nonlinear sensor fault diagnosis in wireless sensor networks

    Science.gov (United States)

    Lo, Chun; Lynch, Jerome P.; Liu, Mingyan

    2016-01-01

    Wireless sensors operating in harsh environments have the potential to be error-prone. This paper presents a distributive model-based diagnosis algorithm that identifies nonlinear sensor faults. The diagnosis algorithm has advantages over existing fault diagnosis methods such as centralized model-based and distributive model-free methods. An algorithm is presented for detecting common non-linearity faults without using reference sensors. The study introduces a model-based fault diagnosis framework that is implemented within a pair of wireless sensors. The detection of sensor nonlinearities is shown to be equivalent to solving the largest empty rectangle (LER) problem, given a set of features extracted from an analysis of sensor outputs. A low-complexity algorithm that gives an approximate solution to the LER problem is proposed for embedment in resource constrained wireless sensors. By solving the LER problem, sensors corrupted by non-linearity faults can be isolated and identified. Extensive analysis evaluates the performance of the proposed algorithm through simulation.

  1. Ground Penetrating Radar as a Contextual Sensor for Multi-Sensor Radiological Characterisation

    Directory of Open Access Journals (Sweden)

    Ikechukwu K. Ukaegbu

    2017-04-01

    Full Text Available Radioactive sources exist in environments or contexts that influence how they are detected and localised. For instance, the context of a moving source is different from a stationary source because of the effects of motion. The need to incorporate this contextual information in the radiation detection and localisation process has necessitated the integration of radiological and contextual sensors. The benefits of the successful integration of both types of sensors is well known and widely reported in fields such as medical imaging. However, the integration of both types of sensors has also led to innovative solutions to challenges in characterising radioactive sources in non-medical applications. This paper presents a review of such recent applications. It also identifies that these applications mostly use visual sensors as contextual sensors for characterising radiation sources. However, visual sensors cannot retrieve contextual information about radioactive wastes located in opaque environments encountered at nuclear sites, e.g., underground contamination. Consequently, this paper also examines ground-penetrating radar (GPR as a contextual sensor for characterising this category of wastes and proposes several ways of integrating data from GPR and radiological sensors. Finally, it demonstrates combined GPR and radiation imaging for three-dimensional localisation of contamination in underground pipes using radiation transport and GPR simulations.

  2. Wireless Biological Electronic Sensors.

    Science.gov (United States)

    Cui, Yue

    2017-10-09

    The development of wireless biological electronic sensors could open up significant advances for both fundamental studies and practical applications in a variety of areas, including medical diagnosis, environmental monitoring, and defense applications. One of the major challenges in the development of wireless bioelectronic sensors is the successful integration of biosensing units and wireless signal transducers. In recent years, there are a few types of wireless communication systems that have been integrated with biosensing systems to construct wireless bioelectronic sensors. To successfully construct wireless biological electronic sensors, there are several interesting questions: What types of biosensing transducers can be used in wireless bioelectronic sensors? What types of wireless systems can be integrated with biosensing transducers to construct wireless bioelectronic sensors? How are the electrical sensing signals generated and transmitted? This review will highlight the early attempts to address these questions in the development of wireless biological electronic sensors.

  3. Sensor technology foresight

    DEFF Research Database (Denmark)

    Andersen, Per Dannemand; Jørgensen, Birte Holst; Rasmussen, Birgitte

    2001-01-01

    , robustness, dispensability, and the abilityto be self-calibrating. Future sensors are expected to be integrated systems with multiple applications. The market sectors most influenced by new sensor technology change from topic to topic. But a general conclusion is that health care is the marketsector most......The Sensor Technology Center A/S (STC) in co-operation with Risoe National Laboratory has carried out a sensor technology foresight in order to strengthen a strategic outlook on sensor technology. The technology foresight (with a timeframe of 2000 to2015) has been performed in the period October...... 2000 - September 2001. The conclusions of the sensor technology report are based on 1) a scanning of existing forward looking literature on sensor technology, 2) a number of workshops with Danish andinternational participants and 3) an international survey with 174 respondents. Half of the respondents...

  4. Silicon force sensor

    Energy Technology Data Exchange (ETDEWEB)

    Galambos, Paul C.; Crenshaw, Thomas B.; Nishida, Erik E.; Burnett, Damon J.; Lantz, Jeffrey W.

    2016-07-05

    The various technologies presented herein relate to a sensor for measurement of high forces and/or high load shock rate(s), whereby the sensor utilizes silicon as the sensing element. A plate of Si can have a thinned region formed therein on which can be formed a number of traces operating as a Wheatstone bridge. The brittle Si can be incorporated into a layered structure comprising ductile and/or compliant materials. The sensor can have a washer-like configuration which can be incorporated into a nut and bolt configuration, whereby tightening of the nut and bolt can facilitate application of a compressive preload upon the sensor. Upon application of an impact load on the bolt, the compressive load on the sensor can be reduced (e.g., moves towards zero-load), however the magnitude of the preload can be such that the load on the sensor does not translate to tensile stress being applied to the sensor.

  5. MEMS optical sensor

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention relates to an all-optical sensor utilizing effective index modulation of a waveguide and detection of a wavelength shift of reflected light and a force sensing system accommodating said optical sensor. One embodiment of the invention relates to a sensor system comprising...... at least one multimode light source, one or more optical sensors comprising a multimode sensor optical waveguide accommodating a distributed Bragg reflector, at least one transmitting optical waveguide for guiding light from said at least one light source to said one or more multimode sensor optical...... waveguides, a detector for measuring light reflected from said Bragg reflector in said one or more multimode sensor optical waveguides, and a data processor adapted for analyzing variations in the Bragg wavelength of at least one higher order mode of the reflected light....

  6. Development of an equipment diagnostic system that evaluates sensor drift

    International Nuclear Information System (INIS)

    Kanada, Masaki; Arita, Setsuo; Tada, Nobuo; Yokota, Katsuo

    2011-01-01

    The importance of condition monitoring technology for equipment has increased with the introduction of condition-based maintenance in nuclear power plants. We are developing a diagnostic system using process signals for plant equipment, such as pumps and motors. It is important to enable the diagnostic system to distinguish sensor drift and equipment failure. We have developed a sensor drift diagnostic method that combines some highly correlative sensor signals by using the MT (Mahalanobis-Taguchi) method. Furthermore, we have developed an equipment failure diagnostic method that measures the Mahalanobis distance from the normal state of equipment by the MT method. These methods can respectively detect sensor drift and equipment failure, but there are the following problems. In the sensor drift diagnosis, there is a possibility of misjudging the sensor drift when the equipment failure occurs and the process signal changes because the behavior of the process signal is the same as that of the sensor drift. Oppositely, in the equipment failure diagnosis, there is a possibility of misjudging the equipment failure when the sensor drift occurs because the sensor drift influences the change of process signal. To solve these problems, we propose a diagnostic method combining the sensor drift diagnosis and the equipment failure diagnosis by the MT method. Firstly, the sensor drift values are estimated by the sensor drift diagnosis, and the sensor drift is removed from the process signal. It is necessary to judge the validity of the estimated sensor drift values before removing the sensor drift from the process signal. We developed a method for judging the validity of the estimated sensor drift values by using the drift distribution based on the sensor calibration data. And then, the equipment failure is diagnosed by using the process signals after removal of the sensor drifts. To verify the developed diagnostic system, several sets of simulation data based on abnormal cases

  7. Digital Sensor Technology

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Ken D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Quinn, Edward L. [Technology Resources, Dana Point, CA (United States); Mauck, Jerry L. [Technology Resources, Dana Point, CA (United States); Bockhorst, Richard M. [Technology Resources, Dana Point, CA (United States)

    2015-02-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy and reliability. This paper, which refers to a final report issued in 2013, demonstrates these benefits in direct comparisons of digital and analog sensor applications. Improved accuracy results from the superior operating characteristics of digital sensors. These include improvements in sensor accuracy and drift and other related parameters which reduce total loop uncertainty and thereby increase safety and operating margins. An example instrument loop uncertainty calculation for a pressure sensor application is presented to illustrate these improvements. This is a side-by-side comparison of the instrument loop uncertainty for both an analog and a digital sensor in the same pressure measurement application. Similarly, improved sensor reliability is illustrated with a sample calculation for determining the probability of failure on demand, an industry standard reliability measure. This looks at equivalent analog and digital temperature sensors to draw the comparison. The results confirm substantial reliability improvement with the digital sensor, due in large part to ability to continuously monitor the health of a digital sensor such that problems can be immediately identified and corrected. This greatly reduces the likelihood of a latent failure condition of the sensor at the time of a design basis event. Notwithstanding the benefits of digital sensors, there are certain qualification issues that are inherent with digital technology and these are described in the report. One major qualification impediment for digital sensor implementation is software common cause failure (SCCF).

  8. The effect of sensor errors on production and energy consumption in greenhouse horticulture

    NARCIS (Netherlands)

    Bontsema, J.; Henten, van E.J.; Gieling, T.H.; Swinkels, G.L.A.M.

    2011-01-01

    The accuracy of sensors used in Dutch greenhouses for climate control has been assessed and the influence of sensor errors on the energy consumption and crop production has been determined using model simulations. It is shown that currently used sensors are prone to errors exceeding current

  9. Time synchronization in ad-hoc wireless sensor networks

    Science.gov (United States)

    Sharma, Nishant

    2013-06-01

    Advances in micro-electronics and developments in the various technologies have given birth to this era of wireless sensor networks. A sensor network is the one which provides information about the surrounding environment by sensing it and clock synchronization in wireless sensor networks plays a vital role to maintain the integrity of entire network. In this paper two major low energy consumption clock synchronization algorithms, Reference Broadcast Synchronization (RBS) and Timing-Sync Protocol for Sensor Networks (TPSN) are simulated, which result in high level of accuracy, reliability, handles substantially greater node densities, supports mobility, and hence perform well under all possible conditions.

  10. Illumination-based synchronization of high-speed vision sensors.

    Science.gov (United States)

    Hou, Lei; Kagami, Shingo; Hashimoto, Koichi

    2010-01-01

    To acquire images of dynamic scenes from multiple points of view simultaneously, the acquisition time of vision sensors should be synchronized. This paper describes an illumination-based synchronization method derived from the phase-locked loop (PLL) algorithm. Incident light to a vision sensor from an intensity-modulated illumination source serves as the reference signal for synchronization. Analog and digital computation within the vision sensor forms a PLL to regulate the output signal, which corresponds to the vision frame timing, to be synchronized with the reference. Simulated and experimental results show that a 1,000 Hz frame rate vision sensor was successfully synchronized with 32 μs jitters.

  11. Tunnel Magnetoresistance Sensors with Magnetostrictive Electrodes: Strain Sensors.

    Science.gov (United States)

    Tavassolizadeh, Ali; Rott, Karsten; Meier, Tobias; Quandt, Eckhard; Hölscher, Hendrik; Reiss, Günter; Meyners, Dirk

    2016-11-11

    Magnetostrictive tunnel magnetoresistance (TMR) sensors pose a bright perspective in micro- and nano-scale strain sensing technology. The behavior of TMR sensors under mechanical stress as well as their sensitivity to the applied stress depends on the magnetization configuration of magnetic tunnel junctions (MTJ)s with respect to the stress axis. Here, we propose a configuration resulting in an inverse effect on the tunnel resistance by tensile and compressive stresses. Numerical simulations, based on a modified Stoner-Wohlfarth (SW) model, are performed in order to understand the magnetization reversal of the sense layer and to find out the optimum bias magnetic field required for high strain sensitivity. At a bias field of -3.2 kA/m under a 0.2 × 10 - 3 strain, gauge factors of 2294 and -311 are calculated under tensile and compressive stresses, respectively. Modeling results are investigated experimentally on a round junction with a diameter of 30 ± 0.2 μ m using a four-point bending apparatus. The measured field and strain loops exhibit nearly the same trends as the calculated ones. Also, the gauge factors are in the same range. The junction exhibits gauge factors of 2150 ± 30 and -260 for tensile and compressive stresses, respectively, under a -3.2 kA/m bias magnetic field. The agreement of the experimental and modeling results approves the proposed configuration for high sensitivity and ability to detect both tensile and compressive stresses by a single TMR sensor.

  12. HEAT Sensor: Harsh Environment Adaptable Thermionic Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Limb, Scott J. [Palo Alto Research Center, Palo Alto, CA (United States)

    2016-05-31

    This document is the final report for the “HARSH ENVIRONMENT ADAPTABLE THERMIONIC SENSOR” project under NETL’s Crosscutting contract DE-FE0013062. This report addresses sensors that can be made with thermionic thin films along with the required high temperature hermetic packaging process. These sensors can be placed in harsh high temperature environments and potentially be wireless and self-powered.

  13. RF sensor for multiphase flow measurement through an oil pipeline

    Science.gov (United States)

    Wylie, S. R.; Shaw, A.; Al-Shamma'a, A. I.

    2006-08-01

    We have developed, in conjunction with Solartron ISA, an electromagnetic cavity resonator based sensor for multiphase flow measurement through an oil pipeline. This sensor is non-intrusive and transmits low power (10 mW) radio frequencies (RF) in the range of 100-350 MHz and detects the pipeline contents using resonant peaks captured instantaneously. The multiple resonances from each captured RF spectrum are analysed to determine the phase fractions in the pipeline. An industrial version of the sensor for a 102 mm (4 inch) diameter pipe has been constructed and results from this sensor are compared to those given by simulations performed using the electromagnetic high frequency structure simulator software package HFSS. This paper was presented at the 13th International Conference on Sensors and held in Chatham, Kent, on 6-7 September 2005.

  14. Estimating spacecraft attitude based on in-orbit sensor measurements

    DEFF Research Database (Denmark)

    Jakobsen, Britt; Lyn-Knudsen, Kevin; Mølgaard, Mathias

    2014-01-01

    , attitude and rotational velocity, the EKF proves to be robust against noisy or lacking sensor data. It is apparent from the comparison of noise parameters from Earth and space, that an EKF tuned using Earth measurements of sensor variances will attain an acceptable performance when operated in Low Earth...... from a controlled environment on Earth as well as in-orbit. By using sensor noise parameters obtained on Earth as the expected parameters in the attitude estimation, and simulating the environment using the sensor noise parameters from space, it is possible to assess whether the EKF can be designed...... solely on Earth or whether an in-orbit tuning/update of the algorithm is needed. of the EKF. Generally, sensor noise variances are larger in the in-orbit measurements than in the measurements obtained on ground. From Monte Carlo simulations with varying settings of the satellite inertia and initial time...

  15. RF sensor solutions for small lightweight unmanned aerial vehicles

    Science.gov (United States)

    Innocenti, Roberto

    2005-05-01

    A need exists for greater situational awareness at the lower echelons of the Army. Radar Frequency (RF) sensors on small, lightweight Unmanned Aerial Vehicles (UAV) could provide lower echelon commanders with all-weather reconnaissance, early warning, and target acquisition; however, the designs of these RF sensors are limited by the projected size and weight restrictions on the payload for a class II UAV. Consequently, these designs may favor combining simple RF sensor hardware with digital-signal processing (DSP) solutions over more sophisticated radar hardware. In this paper, we show the potential of simple, low cost RF sensors with hemispherical antenna coverage to overcome these limitations. The proposed RF sensor system used DSP and pre-defined UAV flight pattern to detect and track moving targets from range and Doppler information. Our objective is to conceive and model a suite of software options that, by combining UAV flight patterns and processing algorithms, will be able to detect and track moving targets. In order to accomplish this, we are building a simulation that uses sensor models, target models, and battlefield dynamics to predict the targeting capabilities of the RF sensor system. We will use this simulation (1) to determine the tradeoffs between sensor complexity (and cost) and the military significance of the information gathered, and (2) to describe sensor error budgets for endgame lethality models

  16. Feature extraction and sensor selection for NPP initiating event identification

    International Nuclear Information System (INIS)

    Lin, Ting-Han; Wu, Shun-Chi; Chen, Kuang-You; Chou, Hwai-Pwu

    2017-01-01

    Highlights: • A two-stage feature extraction scheme for NPP initiating event identification. • With stBP, interrelations among the sensors can be retained for identification. • With dSFS, sensors that are crucial for identification can be efficiently selected. • Efficacy of the scheme is illustrated with data from the Maanshan NPP simulator. - Abstract: Initiating event identification is essential in managing nuclear power plant (NPP) severe accidents. In this paper, a novel two-stage feature extraction scheme that incorporates the proposed sensor type-wise block projection (stBP) and deflatable sequential forward selection (dSFS) is used to elicit the discriminant information in the data obtained from various NPP sensors to facilitate event identification. With the stBP, the primal features can be extracted without eliminating the interrelations among the sensors of the same type. The extracted features are then subjected to a further dimensionality reduction by selecting the sensors that are most relevant to the events under consideration. This selection is not easy, and a combinatorial optimization technique is normally required. With the dSFS, an optimal sensor set can be found with less computational load. Moreover, its sensor deflation stage allows sensors in the preselected set to be iteratively refined to avoid being trapped into a local optimum. Results from detailed experiments containing data of 12 event categories and a total of 112 events generated with a Taiwan’s Maanshan NPP simulator are presented to illustrate the efficacy of the proposed scheme.

  17. Sensor for metal detection

    KAUST Repository

    Kodzius, Rimantas

    2014-06-26

    NOVELTY - The sensor has a microfluidic flow channel that is provided with an inlet port, an outlet port, and a detection chamber. The detection chamber is provided with a group of sensing electrodes (4) having a working electrode (8), a counter electrode (9), and a reference electrode (10). A flow sensor is configured to measure flow in the channel. A temperature sensor (6) is configured to measure temperature in the channel (3). An electrical connection is configured to connect the sensor to a sensing device. USE - Sensor for detecting metal such as toxic metal in sample such as clinical sample such as stool, saliva, sputum, bronchial lavage, urine, vaginal swab, nasal swab, biopsy, tissue, tears, breath, blood, serum, plasma, cerebrospinal fluid, peritoneal fluid, pleural fluid, pericardial fluid, joint fluid, and amniotic fluid, water sample, food sample, air sample, and soil sample (all claimed). ADVANTAGE - The sensor for use with the portable analytical instrument is configured for detection of metalsin samples. The sensor can provide the excellent solution for on-site metal detection, including heavy metal detection. The sensors can provide significant advantages in higher throughput, lower cost, at the same time being less labor intensive and less dependent on individual skills. The disposable design of the sensor, the enhanced reliability and repeatability of measurements can be obtained. The sensors can be widely applied in various industries. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a system for detecting metal in sample; and (2) a method for using sensor for detecting metal in sample. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the sensor prototype. Channel (3) Sensing electrodes (4) Temperature sensor (6) Working electrode (8) Counter electrode (9) Reference electrode (10)

  18. New Leakage Current Particulate Matter Sensor for On-Board Diagnostics

    Directory of Open Access Journals (Sweden)

    Jiawei Wang

    2016-01-01

    Full Text Available Structure and principle of the new leakage current particulate matter (PM sensor are introduced and further study is performed on the PM sensor with the combination of numerical simulation and bench test. High voltage electrode, conductive shell, and heaters are all built-in. Based on the principle of Venturi tube and maze structure design, this sensor can detect transient PM concentrations. Internal flow field of the sensor and distribution condition of PM inside the sensor are analyzed through gas-solid two-phase flow numerical simulation. The experiment was also carried out on the whole sensor system (including mechanical and electronic circuit part and the output signals were analyzed. The results of simulation and experiment reveal the possibility of PM concentration (mass detection by the sensor.

  19. Multiple Waveband Temperature Sensor (MWTS)

    Science.gov (United States)

    Bandara, Sumith V.; Gunapala, Sarath; Wilson, Daniel; Stirbl, Robert; Blea, Anthony; Harding, Gilbert

    2006-01-01

    This slide presentation reviews the development of Multiple Waveband Temperature Sensor (MWTS). The MWTS project will result in a highly stable, monolithically integrated, high resolution infrared detector array sensor that records registered thermal imagery in four infrared wavebands to infer dynamic temperature profiles on a laser-irradiated ground target. An accurate surface temperature measurement of a target in extreme environments in a non-intrusive manner is required. The development challenge is to: determine optimum wavebands (suitable for target temperatures, nature of the targets and environments) to measure accurate target surface temperature independent of the emissivity, integrate simultaneously readable multiband Quantum Well Infrared Photodetectors (QWIPs) in a single monolithic focal plane array (FPA) sensor and to integrate the hardware/software and system calibration for remote temperature measurements. The charge was therefore to develop and demonstrate a multiband infrared imaging camera with the detectors simultaneously sensitive to multiple distinct color bands for front surface temperature measurements Wavelength ( m) measurements. Amongst the requirements are: that the measurement system will not affect target dynamics or response to the laser irradiation and that the simplest criterion for spectral band selection is to choose those practically feasible spectral bands that create the most contrast between the objects or scenes of interest in the expected environmental conditions. There is in the presentation a review of the modeling and simulation of multi-wave infrared temperature measurement and also a review of the detector development and QWIP capacities.

  20. Malfunctions in radioactivity sensors' networks

    Science.gov (United States)

    Khalipova, Veronika; Damart, Guillaume; Beauzamy, Bernard; Bruna, Giovanni

    2018-01-01

    The capacity to promptly and efficiently detect any source of contamination of the environment (a radioactive cloud) at a local and a country scale is mandatory to a safe and secure exploitation of civil nuclear energy. It must rely upon a robust network of measurement devices, to be optimized vs. several parameters, including the overall reliability, the investment, the operation and maintenance costs. We show that a network can be arranged in different ways, but many of them are inadequate. Through simulations, we test the efficiency of several configurations of sensors, in the same domain. The denser arrangement turns out to be the more efficient, but the efficiency is increased when sensors are non-uniformly distributed over the country, with accumulation at the borders. In the case of France, as radioactive threats are most likely to come from the East, the best solution is densifying the sensors close to the eastern border. Our approach differs from previous work because it is "failure oriented": we determine the laws of probability for all types of failures and deduce in this respect the best organization of the network.

  1. Malfunctions in radioactivity sensors' networks

    Directory of Open Access Journals (Sweden)

    Khalipova Veronika

    2018-01-01

    Full Text Available The capacity to promptly and efficiently detect any source of contamination of the environment (a radioactive cloud at a local and a country scale is mandatory to a safe and secure exploitation of civil nuclear energy. It must rely upon a robust network of measurement devices, to be optimized vs. several parameters, including the overall reliability, the investment, the operation and maintenance costs. We show that a network can be arranged in different ways, but many of them are inadequate. Through simulations, we test the efficiency of several configurations of sensors, in the same domain. The denser arrangement turns out to be the more efficient, but the efficiency is increased when sensors are non-uniformly distributed over the country, with accumulation at the borders. In the case of France, as radioactive threats are most likely to come from the East, the best solution is densifying the sensors close to the eastern border. Our approach differs from previous work because it is "failure oriented": we determine the laws of probability for all types of failures and deduce in this respect the best organization of the network.

  2. Error propagation analysis for a sensor system

    Energy Technology Data Exchange (ETDEWEB)

    Yeater, M.L.; Hockenbury, R.W.; Hawkins, J.; Wilkinson, J.

    1976-01-01

    As part of a program to develop reliability methods for operational use with reactor sensors and protective systems, error propagation analyses are being made for each model. An example is a sensor system computer simulation model, in which the sensor system signature is convoluted with a reactor signature to show the effect of each in revealing or obscuring information contained in the other. The error propagation analysis models the system and signature uncertainties and sensitivities, whereas the simulation models the signatures and by extensive repetitions reveals the effect of errors in various reactor input or sensor response data. In the approach for the example presented, the errors accumulated by the signature (set of ''noise'' frequencies) are successively calculated as it is propagated stepwise through a system comprised of sensor and signal processing components. Additional modeling steps include a Fourier transform calculation to produce the usual power spectral density representation of the product signature, and some form of pattern recognition algorithm.

  3. MITRE sensor layer prototype

    Science.gov (United States)

    Duff, Francis; McGarry, Donald; Zasada, David; Foote, Scott

    2009-05-01

    The MITRE Sensor Layer Prototype is an initial design effort to enable every sensor to help create new capabilities through collaborative data sharing. By making both upstream (raw) and downstream (processed) sensor data visible, users can access the specific level, type, and quantities of data needed to create new data products that were never anticipated by the original designers of the individual sensors. The major characteristic that sets sensor data services apart from typical enterprise services is the volume (on the order of multiple terabytes) of raw data that can be generated by most sensors. Traditional tightly coupled processing approaches extract pre-determined information from the incoming raw sensor data, format it, and send it to predetermined users. The community is rapidly reaching the conclusion that tightly coupled sensor processing loses too much potentially critical information.1 Hence upstream (raw and partially processed) data must be extracted, rapidly archived, and advertised to the enterprise for unanticipated uses. The authors believe layered sensing net-centric integration can be achieved through a standardize-encapsulate-syndicateaggregate- manipulate-process paradigm. The Sensor Layer Prototype's technical approach focuses on implementing this proof of concept framework to make sensor data visible, accessible and useful to the enterprise. To achieve this, a "raw" data tap between physical transducers associated with sensor arrays and the embedded sensor signal processing hardware and software has been exploited. Second, we encapsulate and expose both raw and partially processed data to the enterprise within the context of a service-oriented architecture. Third, we advertise the presence of multiple types, and multiple layers of data through geographic-enabled Really Simple Syndication (GeoRSS) services. These GeoRSS feeds are aggregated, manipulated, and filtered by a feed aggregator. After filtering these feeds to bring just the type

  4. Optical arc sensor using energy harvesting power source

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoo Nam, E-mail: knchoi@inu.ac.kr; Rho, Hee Hyuk, E-mail: rdoubleh0902@inu.ac.kr [Dept. of Information and Telecommunication Engineering Incheon National University Incheon 22012 (Korea, Republic of)

    2016-06-03

    Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arc energy levels, with a resolution below 17 J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.

  5. Optical arc sensor using energy harvesting power source

    Science.gov (United States)

    Choi, Kyoo Nam; Rho, Hee Hyuk

    2016-06-01

    Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arc energy levels, with a resolution below 17J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.

  6. MEMS magnetic field sensor based on silicon bridge structure

    Energy Technology Data Exchange (ETDEWEB)

    Du Guangtao; Chen Xiangdong; Lin Qibin; Li Hui; Guo Huihui, E-mail: xdchen@home.swjtu.edu.c [School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031 (China)

    2010-10-15

    A MEMS piezoresistive magnetic field sensor based on a silicon bridge structure has been simulated and tested. The sensor consists of a silicon sensitivity diaphragm embedded with a piezoresistive Wheatstone bridge, and a ferromagnetic magnet adhered to the sensitivity diaphragm. When the sensor is subjected to an external magnetic field, the magnetic force bends the silicon sensitivity diaphragm, producing stress and resistors change of the Wheatstone bridge and the output voltage of the sensor. Good agreement is observed between the theory and measurement behavior of the magnetic field sensor. Experimental results demonstrate that the maximum sensitivity and minimum resolution are 48 m V/T and 160 {mu}T, respectively, making this device suitable for strong magnetic field measurement. Research results indicate that the sensor repeatability and dynamic response time are about 0.66% and 150 ms, respectively. (semiconductor devices)

  7. Ultrasensitive displacement sensor based on tunable horn-shaped resonators

    Science.gov (United States)

    Tian, Ying; Wu, Jiong; Yu, Le; Yang, Helin; Huang, Xiaojun

    2018-04-01

    In this paper, we proposed a novel double-deck displacement sensor with a high linearity based on tunable horn-shaped resonators. The designed sensor included two substrate layers etched with copper metallization in various shapes. When the upper trip-type resonator layer has a relative displacement to the bottom horn-shaped resonator layer, the resonance frequency of the sensor is redshift. High sensitivity of the sensor is around 207.2 MHz mm‑1 with 4 mm linear dynamic range. We fabricate the sample of the proposed displacement sensor, in addition the simulated results are verified by experiment. The proposed displacement sensor is appropriate for using MEMS technology in further miniaturization.

  8. Development of coaxial speaker-like non-contact electrostatic sensor for aviation engine exhaust electrostatic character research

    Directory of Open Access Journals (Sweden)

    Du Zhaoheng

    2015-01-01

    Full Text Available Electrostatic sensor is the most important equipment in aero-engine exhaust electrostatic character research. By comparing a variety of sensor test programs, the coaxial speaker-like noncontact electrostatic sensor program is proposed. Numerical simulation analysis indicates the electric field distribution of electrostatic sensor, the influence principle of gap width, outer diameter, center diameter, angle and other factors on the sensor capacitance values which identify the key indicators of electrostatic sensor. The experiment test shows that the simulation analysis is in good agreement with the experimental results.

  9. Working Group Report: Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Artuso, M.; et al.,

    2013-10-18

    Sensors play a key role in detecting both charged particles and photons for all three frontiers in Particle Physics. The signals from an individual sensor that can be used include ionization deposited, phonons created, or light emitted from excitations of the material. The individual sensors are then typically arrayed for detection of individual particles or groups of particles. Mounting of new, ever higher performance experiments, often depend on advances in sensors in a range of performance characteristics. These performance metrics can include position resolution for passing particles, time resolution on particles impacting the sensor, and overall rate capabilities. In addition the feasible detector area and cost frequently provides a limit to what can be built and therefore is often another area where improvements are important. Finally, radiation tolerance is becoming a requirement in a broad array of devices. We present a status report on a broad category of sensors, including challenges for the future and work in progress to solve those challenges.

  10. Clementine sensor suite

    Energy Technology Data Exchange (ETDEWEB)

    Ledebuhr, A.G. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    LLNL designed and built the suite of six miniaturized light-weight space-qualified sensors utilized in the Clementine mission. A major goal of the Clementine program was to demonstrate technologies originally developed for Ballistic Missile Defense Organization Programs. These sensors were modified to gather data from the moon. This overview presents each of these sensors and some preliminary on-orbit performance estimates. The basic subsystems of these sensors include optical baffles to reject off-axis stray light, light-weight ruggedized optical systems, filter wheel assemblies, radiation tolerant focal plane arrays, radiation hardened control and readout electronics and low mass and power mechanical cryogenic coolers for the infrared sensors. Descriptions of each sensor type are given along with design specifications, photographs and on-orbit data collected.

  11. The Ringcore Fluxgate Sensor

    DEFF Research Database (Denmark)

    Brauer, Peter

    1997-01-01

    A model describing the fundamental working principle of the "ringcore fluxgate sensor" is derived. The model is solely based on geometrical and measurable magnetic properties of the sensor and from this a number of fluxgate phenomenon can be described and estimated. The sensitivity of ringcore...... fluxgate sensors is measured for a large variety of geometries and is for all measurements found to fall between two limits obtained by the fluxgate model. The model is used to explain the zero field odd harmonic output of the fluxgate sensor, called the "feedthrough". By assuming a non ideal sensor...... with spatially distributed magnetization, the model predicts feedthrough signals which exactly reflects the measured signals. The non-linearities in a feedback compensated ringcore fluxgate sensors, called the "transverse field effect", can also be explained by the model. Measurements on stress annealed...

  12. Capacitive chemical sensor

    Science.gov (United States)

    Manginell, Ronald P; Moorman, Matthew W; Wheeler, David R

    2014-05-27

    A microfabricated capacitive chemical sensor can be used as an autonomous chemical sensor or as an analyte-sensitive chemical preconcentrator in a larger microanalytical system. The capacitive chemical sensor detects changes in sensing film dielectric properties, such as the dielectric constant, conductivity, or dimensionality. These changes result from the interaction of a target analyte with the sensing film. This capability provides a low-power, self-heating chemical sensor suitable for remote and unattended sensing applications. The capacitive chemical sensor also enables a smart, analyte-sensitive chemical preconcentrator. After sorption of the sample by the sensing film, the film can be rapidly heated to release the sample for further analysis. Therefore, the capacitive chemical sensor can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

  13. Development of a Capacitive Ice Sensor to Measure Ice Growth in Real Time

    OpenAIRE

    Zhi, Xiang; Cho, Hyo Chang; Wang, Bo; Ahn, Cheol Hee; Moon, Hyeong Soon; Go, Jeung Sang

    2015-01-01

    This paper presents the development of the capacitive sensor to measure the growth of ice on a fuel pipe surface in real time. The ice sensor consists of pairs of electrodes to detect the change in capacitance and a thermocouple temperature sensor to examine the ice formation situation. In addition, an environmental chamber was specially designed to control the humidity and temperature to simulate the ice formation conditions. From the humidity, a water film is formed on the ice sensor, which...

  14. Performance of terahertz metamaterials as high-sensitivity sensor

    Science.gov (United States)

    He, Yanan; Zhang, Bo; Shen, Jingling

    2017-09-01

    A high-sensitivity sensor based on the resonant transmission characteristics of terahertz (THz) metamaterials was investigated, with the proposal and fabrication of rectangular bar arrays of THz metamaterials exhibiting a period of 180 μm on a 25 μm thick flexible polyimide. Varying the size of the metamaterial structure revealed that the length of the rectangular unit modulated the resonant frequency, which was verified by both experiment and simulation. The sensing characteristics upon varying the surrounding media in the sample were tested by simulation and experiment. Changing the surrounding medium from that of air to that of alcohol or oil produced resonant frequency redshifts of 80 GHz or 150 GHz, respectively, which indicates that the sensor possessed a high sensitivity of 667 GHz per unit of refractive index. Finally, the influence of the sample substrate thickness on the sensor sensitivity was investigated by simulation. It may be a reference for future sensor design.

  15. Bioinspired Sensor Systems

    Directory of Open Access Journals (Sweden)

    Manel del Valle

    2011-10-01

    Full Text Available This editorial summarizes and classifies the contributions presented by different authors to the special issue of the journal Sensors dedicated to Bioinspired Sensor Systems. From the coupling of sensor arrays or networks, plus computer processing abilities, new applications to mimic or to complement human senses are arising in the context of ambient intelligence. Principles used, and illustrative study cases have been presented permitting readers to grasp the current status of the field.

  16. Perimeter intrusion sensors

    International Nuclear Information System (INIS)

    Eaton, M.J.

    1977-01-01

    To obtain an effective perimeter intrusion detection system requires careful sensor selection, procurement, and installation. The selection process involves a thorough understanding of the unique site features and how these features affect the performance of each type of sensor. It is necessary to develop procurement specifications to establish acceptable sensor performance limits. Careful explanation and inspection of critical installation dimensions is required during on-site construction. The implementation of these activities at a particular site is discussed

  17. Magnetic actuators and sensors

    CERN Document Server

    Brauer, John R

    2014-01-01

    An accessible, comprehensive guide on magnetic actuators and sensors, this fully updated second edition of Magnetic Actuators and Sensors includes the latest advances, numerous worked calculations, illustrations, and real-life applications. Covering magnetics, actuators, sensors, and systems, with updates of new technologies and techniques, this exemplary learning tool emphasizes computer-aided design techniques, especially magnetic finite element analysis, commonly used by today's engineers. Detailed calculations, numerous illustrations, and discussions of discrepancies make this text an inva

  18. High-temperature sensor

    Science.gov (United States)

    Not Available

    1981-01-29

    A high temperature sensor is described which includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range (1000 to 2000/sup 0/K). When required, the sensor can be encased within a ceramic protective coating.

  19. Contact stress sensor

    Science.gov (United States)

    Kotovsky, Jack [Oakland, CA

    2012-02-07

    A contact stress sensor includes one or more MEMS fabricated sensor elements, where each sensor element of includes a thin non-recessed portion, a recessed portion and a pressure sensitive element adjacent to the recessed portion. An electric circuit is connected to the pressure sensitive element. The circuit includes a thermal compensator and a pressure signal circuit element configured to provide a signal upon movement of the pressure sensitive element.

  20. Implanted electroenzymatic glucose sensors.

    Science.gov (United States)

    Clark, L C; Duggan, C A

    1982-01-01

    The advent of electrochemical sensors for intermittent sampling of blood gases and hydrogen ions in the clinic, intensive care, and surgical units has revolutionized diagnostic and critical care medical technics. The use of electrochemical sensors for continuous transcutaneous monitoring of blood gases is further enhancing the medical surveillance of patients. The more recent introduction of glucose and other electroenzymatic sensors has stimulated broad research in the development of metabolic monitoring. For the present research, the glucose sensor widely used for the rapid specific micro-analysis of whole blood and plasma is explored for possible use as an in vivo intravascular or tissue-implanted sensor. This sensor is based on the polarographic measurement of hydrogen peroxide generated by glucose oxidase (EC 1.1.3.4) held between two membranes. The first membrane allows the diffusion of glucose, ions, and many other small molecules, while the second membrane allows the diffusion of the glucose-generated hydrogen peroxide to the platinum surface, but excludes ascorbic acid, bilirubin, and uric acid. Such sensors respond rapidly and specifically when acutely implanted subcutaneously in cats and dogs. They function well as glucose-sensor-tipped venous catheters. One sensor was repeatedly used for in vitro polarograms, subcutaneous and blood glucose monitoring, over a period of ten months, with storage in the cold between uses, with the complete retention of its response characteristics.

  1. Smart sensors and systems

    CERN Document Server

    Kyung, Chong-Min; Yasuura, Hiroto; Liu, Yongpan

    2015-01-01

     This book describes for readers technology used for effective sensing of our physical world and intelligent processing techniques for sensed information, which are essential to the success of Internet of Things (IoTs).  The authors provide a multidisciplinary view of sensor technology from MEMS, biological, chemical, and electrical domains and showcase smart sensor systems in real applications including smart home, transportation, medical, environmental, agricultural, etc.  Unlike earlier books on sensors, this book will provide a “global” view on smart sensors covering abstraction levels from device, circuit, systems, and algorithms.  .

  2. Palladium Nanoparticle Hydrogen Sensor

    Directory of Open Access Journals (Sweden)

    I. Pavlovsky

    2006-12-01

    Full Text Available An innovative hydrogen sensor based on palladium (Pd nanoparticle networks is described in the article. Made by Applied Nanotech Inc. sensor has a fast response time, in the range of seconds, which is increased at 80 °C due to higher hydrogen diffusion rates into the palladium lattice. The low detection limit of the sensor is 10 ppm of H2, and the high limit is 40,000 ppm. This is 100% of a lowest flammability level of hydrogen. This range of sensitivities complies with the requirements that one would expect for a reliable hydrogen sensor.

  3. Microfabricated Formaldehyde Gas Sensors

    Directory of Open Access Journals (Sweden)

    Karen C. Cheung

    2009-11-01

    Full Text Available Formaldehyde is a volatile organic compound that is widely used in textiles, paper, wood composites, and household materials. Formaldehyde will continuously outgas from manufactured wood products such as furniture, with adverse health effects resulting from prolonged low-level exposure. New, microfabricated sensors for formaldehyde have been developed to meet the need for portable, low-power gas detection. This paper reviews recent work including silicon microhotplates for metal oxide-based detection, enzyme-based electrochemical sensors, and nanowire-based sensors. This paper also investigates the promise of polymer-based sensors for low-temperature, low-power operation.

  4. Smart and Intelligent Sensors

    Science.gov (United States)

    Lansaw, John; Schmalzel, John; Figueroa, Jorge

    2009-01-01

    John C. Stennis Space Center (SSC) provides rocket engine propulsion testing for NASA's space programs. Since the development of the Space Shuttle, every Space Shuttle Main Engine (SSME) has undergone acceptance testing at SSC before going to Kennedy Space Center (KSC) for integration into the Space Shuttle. The SSME is a large cryogenic rocket engine that uses Liquid Hydrogen (LH2) as the fuel. As NASA moves to the new ARES V launch system, the main engines on the new vehicle, as well as the upper stage engine, are currently base lined to be cryogenic rocket engines that will also use LH2. The main rocket engines for the ARES V will be larger than the SSME, while the upper stage engine will be approximately half that size. As a result, significant quantities of hydrogen will be required during the development, testing, and operation of these rocket engines.Better approaches are needed to simplify sensor integration and help reduce life-cycle costs. 1.Smarter sensors. Sensor integration should be a matter of "plug-and-play" making sensors easier to add to a system. Sensors that implement new standards can help address this problem; for example, IEEE STD 1451.4 defines transducer electronic data sheet (TEDS) templates for commonly used sensors such as bridge elements and thermocouples. When a 1451.4 compliant smart sensor is connected to a system that can read the TEDS memory, all information needed to configure the data acquisition system can be uploaded. This reduces the amount of labor required and helps minimize configuration errors. 2.Intelligent sensors. Data received from a sensor be scaled, linearized; and converted to engineering units. Methods to reduce sensor processing overhead at the application node are needed. Smart sensors using low-cost microprocessors with integral data acquisition and communication support offer the means to add these capabilities. Once a processor is embedded, other features can be added; for example, intelligent sensors can make

  5. Data fusion system architecture for unattended ground sensors

    Science.gov (United States)

    Zhang, Junliang; Zhao, Yuming

    1998-03-01

    In this paper, it develops an artificial intelligence method that uses object-oriented approach to construct the blackboard of data fusion for unattended ground sensors including geophone sensor, acoustic sensor, pressure sensor, infra-red sensor, magnetic sensor, image sensor etc.. It can perform detection, correlation, association and estimation to the sensors' output and obtain the exact recognition of targets, the number of target groups and the estimation for both the states of targets and the situation and threat. The whole blackboard is divided into three regions, including: single sensor fusion region, multisensor fusion region and threat estimation region. The three regions are expressed in classes. Knowledges of each domain in the three regions are also expressed by classes and encapsulated in class hierarchy structure. Thus the whole blackboard can be viewed as object forest, the distributed knowledge inference can be realized by object reference. Both statistics and hierarchy inference approaches are used in the blackboard structure so as to efficiently perform fusion and inference. Furthermore, the method is realized in C++ language and demonstrated by the simulation of sensor alarming datum under battlefield environment.

  6. Multitarget Tracking with Spatial Nonmaximum Suppressed Sensor Selection

    Directory of Open Access Journals (Sweden)

    Liang Ma

    2015-01-01

    Full Text Available Multitarget tracking is one of the most important applications of sensor networks, yet it is an extremely challenging problem since multisensor multitarget tracking itself is nontrivial and the difficulty is further compounded by sensor management. Recently, random finite set based Bayesian framework has opened doors for multitarget tracking with sensor management, which is modelled in the framework of partially observed Markov decision process (POMDP. However, sensor management posed as a POMDP is in essence a combinatorial optimization problem which is NP-hard and computationally unacceptable. In this paper, we propose a novel sensor selection method for multitarget tracking. We first present the sequential multi-Bernoulli filter as a centralized multisensor fusion scheme for multitarget tracking. In order to perform sensor selection, we define the hypothesis information gain (HIG of a sensor to measure its information quantity when the sensor is selected alone. Then, we propose spatial nonmaximum suppression approach to select sensors with respect to their locations and HIGs. Two distinguished implementations have been provided using the greedy spatial nonmaximum suppression. Simulation results verify the effectiveness of proposed sensor selection approach for multitarget tracking.

  7. CMOS: Efficient Clustered Data Monitoring in Sensor Networks

    Directory of Open Access Journals (Sweden)

    Jun-Ki Min

    2013-01-01

    Full Text Available Tiny and smart sensors enable applications that access a network of hundreds or thousands of sensors. Thus, recently, many researchers have paid attention to wireless sensor networks (WSNs. The limitation of energy is critical since most sensors are battery-powered and it is very difficult to replace batteries in cases that sensor networks are utilized outdoors. Data transmission between sensor nodes needs more energy than computation in a sensor node. In order to reduce the energy consumption of sensors, we present an approximate data gathering technique, called CMOS, based on the Kalman filter. The goal of CMOS is to efficiently obtain the sensor readings within a certain error bound. In our approach, spatially close sensors are grouped as a cluster. Since a cluster header generates approximate readings of member nodes, a user query can be answered efficiently using the cluster headers. In addition, we suggest an energy efficient clustering method to distribute the energy consumption of cluster headers. Our simulation results with synthetic data demonstrate the efficiency and accuracy of our proposed technique.

  8. CMOS: efficient clustered data monitoring in sensor networks.

    Science.gov (United States)

    Min, Jun-Ki

    2013-01-01

    Tiny and smart sensors enable applications that access a network of hundreds or thousands of sensors. Thus, recently, many researchers have paid attention to wireless sensor networks (WSNs). The limitation of energy is critical since most sensors are battery-powered and it is very difficult to replace batteries in cases that sensor networks are utilized outdoors. Data transmission between sensor nodes needs more energy than computation in a sensor node. In order to reduce the energy consumption of sensors, we present an approximate data gathering technique, called CMOS, based on the Kalman filter. The goal of CMOS is to efficiently obtain the sensor readings within a certain error bound. In our approach, spatially close sensors are grouped as a cluster. Since a cluster header generates approximate readings of member nodes, a user query can be answered efficiently using the cluster headers. In addition, we suggest an energy efficient clustering method to distribute the energy consumption of cluster headers. Our simulation results with synthetic data demonstrate the efficiency and accuracy of our proposed technique.

  9. Scene simulation of terahertz radiation characteristics of the armored vehicle

    Science.gov (United States)

    He, Ye; Jiang, Yuesong; He, Yuntao

    2008-12-01

    Scene simulation of radiation characteristics of targets and backgrounds is an important research topic for its benefits in the adaption and optimization of a sensor and its observation conditions. In this paper, imaging of the armored vehicle, an important and complicated military target, formed by passive terahertz sensors was studied, including calculation of the temperature field, analysis of atmospheric effects and the sensor models.

  10. Simulation of Smart Home Activity Datasets.

    Science.gov (United States)

    Synnott, Jonathan; Nugent, Chris; Jeffers, Paul

    2015-06-16

    A globally ageing population is resulting in an increased prevalence of chronic conditions which affect older adults. Such conditions require long-term care and management to maximize quality of life, placing an increasing strain on healthcare resources. Intelligent environments such as smart homes facilitate long-term monitoring of activities in the home through the use of sensor technology. Access to sensor datasets is necessary for the development of novel activity monitoring and recognition approaches. Access to such datasets is limited due to issues such as sensor cost, availability and deployment time. The use of simulated environments and sensors may address these issues and facilitate the generation of comprehensive datasets. This paper provides a review of existing approaches for the generation of simulated smart home activity datasets, including model-based approaches and interactive approaches which implement virtual sensors, environments and avatars. The paper also provides recommendation for future work in intelligent environment simulation.

  11. Determining the confidence levels of sensor outputs using neural networks

    International Nuclear Information System (INIS)

    Broten, G.S.; Wood, H.C.

    1995-01-01

    This paper describes an approach for determining the confidence level of a sensor output using multi-sensor arrays, sensor fusion and artificial neural networks. The authors have shown in previous work that sensor fusion and artificial neural networks can be used to learn the relationships between the outputs of an array of simulated partially selective sensors and the individual analyte concentrations in a mixture of analyses. Other researchers have shown that an array of partially selective sensors can be used to determine the individual gas concentrations in a gaseous mixture. The research reported in this paper shows that it is possible to extract confidence level information from an array of partially selective sensors using artificial neural networks. The confidence level of a sensor output is defined as a numeric value, ranging from 0% to 100%, that indicates the confidence associated with a output of a given sensor. A three layer back-propagation neural network was trained on a subset of the sensor confidence level space, and was tested for its ability to generalize, where the confidence level space is defined as all possible deviations from the correct sensor output. A learning rate of 0.1 was used and no momentum terms were used in the neural network. This research has shown that an artificial neural network can accurately estimate the confidence level of individual sensors in an array of partially selective sensors. This research has also shown that the neural network's ability to determine the confidence level is influenced by the complexity of the sensor's response and that the neural network is able to estimate the confidence levels even if more than one sensor is in error. The fundamentals behind this research could be applied to other configurations besides arrays of partially selective sensors, such as an array of sensors separated spatially. An example of such a configuration could be an array of temperature sensors in a tank that is not in

  12. Microelectronic temperature sensor; silicon temperature sensor

    International Nuclear Information System (INIS)

    Beitner, M.; Kanert, W.; Reichert, H.

    1982-01-01

    The goal of this work was to develop a silicon temperature sensor with a sensitivity and a reliability as high and a tolerance as small as possible, for use in measurement and control. By employing the principle of spreading-resistance, using silicon doped by neutron transmutation, and trimming of the single wafer tolerances of resistance less than +- 5% can be obtained; overstress tests yielded a long-term stability better than 0.2%. Some applications show the advantageous use of this sensor. (orig.) [de

  13. Simulation Development for Dynamic Situation Awareness and Prediction II

    National Research Council Canada - National Science Library

    Trott, Kevin C

    2006-01-01

    ... within the simulation environment. These simulations provide feedback to prototype C4ISR systems in the form of mission status reports, sensor tracks, and other ISR mission results reports, which can be used to maintain situation...

  14. Nanophotonic Image Sensors

    Science.gov (United States)

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

    2016-01-01

    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. PMID:27239941

  15. Potentiometric anion selective sensors

    NARCIS (Netherlands)

    Antonisse, M.M.G.; Reinhoudt, David

    1999-01-01

    In comparison with selective receptors (and sensors) for cationic species, work on the selective complexation and detection of anions is of more recent date. There are three important components for a sensor, a transducer element, a membrane material that separates the transducer element and the

  16. Systematic Description of Sensors

    NARCIS (Netherlands)

    Regtien, Paulus P.L.; Sydenham, Peter H.; Thorn, Richard

    A sensor performs the exchange of information (thus energy) from one domain to another and therefore it operates on the interface between different physical domains. Several frameworks have been developed for a systematic description of sensors. Basically, they are based on either of two different

  17. Sensor Data Fusion

    DEFF Research Database (Denmark)

    Plascencia, Alfredo; Stepán, Petr

    2006-01-01

    The main contribution of this paper is to present a sensor fusion approach to scene environment mapping as part of a Sensor Data Fusion (SDF) architecture. This approach involves combined sonar array with stereo vision readings.  Sonar readings are interpreted using probability density functions...

  18. Integrated sensor bus

    Science.gov (United States)

    Rutka, M. J.

    1994-03-01

    In this thesis an integrated sensor bus interface is presented. The proposed bus offers a number of interface procedures to enhance the system flexibility. It enables a 13-bit data exchange per message frame, automatic addressing, device clearing and resetting, and handling of service-request and polling procedures. Chapter 1 provides an overview of the existing data transmission technologies. It presents the most popular digital buses along with their application fields. Also other research activities on sensor buses are described. Chapter 2 deals with the requirements which have to be imposed on the desired sensor bus. It shows both communication and compatibility requirements. Chapter 3 introduces the proposed sensor bus. It presents the interface structure together with implemented bus procedures. The detailed description of the proposed sensor bus protocol is given in Chapter 4. It is divided into two parts; a logical layer description (i.e., sensor bus protocol) and a physical layer description (i.e., transmission medium and electrical characteristics). Chapter 5 deals with the compatibility issue. It investigates differences between typical processes used for sensors and digital circuits. Chapter 6 shows the design of a sensor bus interface prototype. In Chapter 7 the performance of the fabricated interface is discussed.

  19. Stretch Sensor Device

    DEFF Research Database (Denmark)

    2013-01-01

    The invention relates to a method for determining stretch values and movement of body parts, e.g. a foot, by analysing stretch data from a stretch sensor. By analysing data from the stretch sensor it is possible to determine stretch samples which are associated with particular motion phases...

  20. Research and Experiments on a Unipolar Capacitive Voltage Sensor

    Directory of Open Access Journals (Sweden)

    Qiang Zhou

    2015-08-01

    Full Text Available Voltage sensors are an important part of the electric system. In service, traditional voltage sensors need to directly contact a high-voltage charged body. Sensors involve a large volume, complex insulation structures, and high design costs. Typically an iron core structure is adopted. As a result, ferromagnetic resonance can occur easily during practical application. Moreover, owing to the multilevel capacitor divider, the sensor cannot reflect the changes of measured voltage in time. Based on the electric field coupling principle, this paper designs a new voltage sensor; the unipolar structure design solves many problems of traditional voltage sensors like the great insulation design difficulty and high costs caused by grounding electrodes. A differential signal input structure is adopted for the detection circuit, which effectively restrains the influence of the common-mode interference signal. Through sensor modeling, simulation and calculations, the structural design of the sensor electrode was optimized, miniaturization of the sensor was realized, the voltage division ratio of the sensor was enhanced, and the phase difference of sensor measurement was weakened. The voltage sensor is applied to a single-phase voltage class line of 10 kV for testing. According to the test results, the designed sensor is able to meet the requirements of accurate and real-time measurement for voltage of the charged conductor as well as to provide a new method for electricity larceny prevention and on-line monitoring of the power grid in an electric system. Therefore, it can satisfy the development demands of the smart power grid.

  1. Parametric investigation of scalable tactile sensors

    Science.gov (United States)

    Saadatzi, Mohammad Nasser; Yang, Zhong; Baptist, Joshua R.; Sahasrabuddhe, Ritvij R.; Wijayasinghe, Indika B.; Popa, Dan O.

    2017-05-01

    In the near future, robots and humans will share the same environment and perform tasks cooperatively. For intuitive, safe, and reliable physical human-robot interaction (pHRI), sensorized robot skins for tactile measurements of contact are necessary. In a previous study, we presented skins consisting of strain gauge arrays encased in silicone encapsulants. Although these structures could measure normal forces applied directly onto the sensing elements, they also exhibited blind spots and response asymmetry to certain loading patterns. This study presents a parametric investigation of piezoresistive polymeric strain gauge that exhibits a symmetric omniaxial response thanks to its novel star-shaped structure. This strain gauge relies on the use of gold micro-patterned star-shaped structures with a thin layer of PEDOT:PSS which is a flexible polymer with piezoresistive properties. In this paper, the sensor is first modeled and comprehensively analyzed in the finite-element simulation environment COMSOL. Simulations include stress-strain loading for a variety of structure parameters such as gauge lengths, widths, and spacing, as well as multiple load locations relative to the gauge. Subsequently, sensors with optimized configurations obtained through simulations were fabricated using cleanroom photolithographic and spin-coating processes, and then experimentally tested. Results show a trend-wise agreement between experiments and simulations.

  2. 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

  3. 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.

  4. Multiagent robotic systems' ambient light sensor

    Science.gov (United States)

    Iureva, Radda A.; Maslennikov, Oleg S.; Komarov, Igor I.

    2017-05-01

    Swarm robotics is one of the fastest growing areas of modern technology. Being subclass of multi-agent systems it inherits the main part of scientific-methodological apparatus of construction and functioning of practically useful complexes, which consist of rather autonomous independent agents. Ambient light sensors (ALS) are widely used in robotics. But speaking about swarm robotics, the technology which has great number of specific features and is developing, we can't help mentioning that its important to use sensors on each robot not only in order to help it to get directionally oriented, but also to follow light emitted by robot-chief or to help to find the goal easier. Key words: ambient light sensor, swarm system, multiagent system, robotic system, robotic complexes, simulation modelling

  5. Photonic Crystal Slab Sensors in Microfluidics

    DEFF Research Database (Denmark)

    Sørensen, Kristian Tølbøl

    thus concentration) gradient, the diffusion length of molecules in flow can be determined. PCS sensors have been in development for the last fewdecades, and both readout systems and sensor substrates are commercially available. However, products on the market predominantly target high-end applications...... as simple an LED and a photo diode. This work has thus far resulted in three manuscripts and one patent, which are attached. The first manuscript, which has been submitted to Computer Physics Communications, describes an open-source algorithm, which integrates with many electromagnetics simulation tools...... such as pharmaceutical development, where their high pricetags are justifiable. In order to lower the entry barrier of the technology, we patented what is currently being marketed as The NanoCuvette, a spectrophotometer cuvette with an embedded PCS sensor. Along with user-friendly software, this enables the use...

  6. Smart Sensor Network System For Environment Monitoring

    Directory of Open Access Journals (Sweden)

    Javed Ali Baloch

    2012-07-01

    Full Text Available SSN (Smart Sensor Network systems could be used to monitor buildings with modern infrastructure, plant sites with chemical pollution, horticulture, natural habitat, wastewater management and modern transport system. To sense attributes of phenomena and make decisions on the basis of the sensed value is the primary goal of such systems. In this paper a Smart Spatially aware sensor system is presented. A smart system, which could continuously monitor the network to observe the functionality and trigger, alerts to the base station if a change in the system occurs and provide feedback periodically, on demand or even continuously depending on the nature of the application. The results of the simulation trials presented in this paper exhibit the performance of a Smart Spatially Aware Sensor Networks.

  7. 2-Sensor Problem

    Directory of Open Access Journals (Sweden)

    Michael Segal

    2004-11-01

    Full Text Available Abstract: Ad-hoc networks of sensor nodes are in general semi-permanently deployed. However, the topology of such networks continuously changes over time, due to the power of some sensors wearing out to new sensors being inserted into the network, or even due to designers moving sensors around during a network re-design phase (for example, in response to a change in the requirements of the network. In this paper, we address the problem of covering a given path by a limited number of sensors — in our case to two, and show its relation to the well-studied matrix multiplication problem.

  8. Fiber optic gas sensor

    Science.gov (United States)

    Chen, Peng (Inventor); Buric, Michael P. (Inventor); Swinehart, Philip R. (Inventor); Maklad, Mokhtar S. (Inventor)

    2010-01-01

    A gas sensor includes an in-fiber resonant wavelength device provided in a fiber core at a first location. The fiber propagates a sensing light and a power light. A layer of a material is attached to the fiber at the first location. The material is able to absorb the gas at a temperature dependent gas absorption rate. The power light is used to heat the material and increases the gas absorption rate, thereby increasing sensor performance, especially at low temperatures. Further, a method is described of flash heating the gas sensor to absorb more of the gas, allowing the sensor to cool, thereby locking in the gas content of the sensor material, and taking the difference between the starting and ending resonant wavelengths as an indication of the concentration of the gas in the ambient atmosphere.

  9. Sensor Network Motes:

    DEFF Research Database (Denmark)

    Leopold, Martin

    This dissertation describes our efforts to improve sensor network performance evaluation and portability, within the context of the sensor network project Hogthrob. In Hogthrob, we faced the challenge of building an sensor network architecture for sow monitoring. This application has hard...... requirements on price and performance, and shows great potential for using sensor networks. Throughout the project we let the application requirements guide our design choices, leading us to push the technologies further to meet the specific goal of the application. In this dissertation, we attack two key...... to investigate these challenges and apart from developing the methodologies, we also present the results of our experiments. In particular, we present a new vector based methodology for performance evaluation of sensor network devices (motes) and applications, based on application specific benchmarking...

  10. Mini Combat Trauma Patient Simulation System Defense Acquisition Challenge Program (DACP): Mini Combat Trauma Patient Simulation (Mini CTPS)

    National Research Council Canada - National Science Library

    2004-01-01

    .... It consists of networked realistic casualty generators, patient simulators and computer-based casualty simulations, virtual patients and equipment, data and sensor recorders, and an After- Action Review System...

  11. PREFACE: Sensors & their Applications XV

    Science.gov (United States)

    Augousti, A.; McConnell, G.

    2009-07-01

    This volume records the Proceedings of the fifteenth conference in the biennial Sensors and Their Applications series that took place at Heriot-Watt University, Edinburgh between 5-7 October 2009. The conference was organised by the Instrument Science and Technology Group of the Institute of Physics. On this occasion, the conference was co-located and co-organised with Optical Fibre Sensors 20, which ran between 5-9 October 2009, continuing a tradition of such collaborations, including more recently Eurosensors XII in Southampton 1998. This year the conference returns to Edinburgh, having last been held there in 1991, with intervening venues including Manchester, Dublin, Glasgow, Southampton, Cardiff, London, Limerick, Chatham and Liverpool. A joint session of S&A XV and OFS was also organised and took place on 6 October 2009, and is recorded here. The conference proceedings record the continuing health and activity of the sensors community in the UK and beyond. The conference brings together contributions from both academics and industrial researchers, providing excellent networking opportunities. It is interesting to note some continuing themes, such as Optical Sensing (reflected also in the joint session), and the perennial popularity, range and excellence of Sensor Applications, as well as newer developments, such as a session on Subsea Instrumentation, which reflects the increasing interest and applicability of work in this field. Similarly, the maturity of Design and Simulation techniques is acknowledged by a session in this area. The sessions across the conference are ably supported by notable contributions from invited speakers. We should like to thank all of our colleagues in the sensor community who have supported this event by contributing manuscripts. Our thanks go also to colleagues in the Instrument Science and Technology Group for their support, and in particular for refereeing the submitted manuscripts. We are also pleased to express our thanks to

  12. PREFACE: Sensors & their Applications XVI

    Science.gov (United States)

    Kyriacou, Panicos; O'Riordan, Alan

    2011-08-01

    This volume records the Proceedings of the sixteenth conference in the biennial Sensors and Their Applications series which took place at the Clarion Hotel, Cork, Ireland between 12-14 September 2011. The conference is organized by the Instrument Science and Technology Group of the Institute of Physics. On this occasion, the conference was hosted by Tyndall National Institute at University College Cork. This year the conference returns to Ireland, having last been held in Limerick in 2003. The conference proceedings record the continuing growth of the sensors community nationally and internationally. The conferences bring together contributions from scientists and engineers from academia, research institutes and industrial establishments, and therefore provide an excellent opportunity for these communities to present and discuss the latest results in the field of sensors, instrumentation and measurement. Amongst the more traditional themes, such as optical sensing, there is growth in new areas such as biomedical sensing and instrumentation, and nanosensing, which is reflected in this volume. Similarly the contribution of modelling and simulation techniques in sensor and instrumentation design and their applications is acknowledged by a session in this area. The sessions across the conference are supported by notable contributions from invited speakers. We would like to thank all of our colleagues in the sensor and instrumentation community who have supported this event by contributing manuscripts. Our thanks also go to Tyndall National Institute for hosting this conference and all the sponsors who, with their generous financial and in-kind contributions, enabled the better organization of this conference. We would also like to thank all the members of the Instrument Science and Technology Group for their support, and in particular for refereeing the submitted manuscripts. We are also pleased to express our thanks to the Conference Department of the Institute of

  13. UAVS and ISR Sensor Technology

    National Research Council Canada - National Science Library

    Butler, Jeffrey

    2001-01-01

    ...) and sensors for airborne intelligence, surveillance, and reconnaissance (ISR) data collection, Additionally, recommendations for optimizing the employment and development of ISR UAVs and sensors are addressed...

  14. Roadmap on optical sensors.

    Science.gov (United States)

    Ferreira, Mário F S; Castro-Camus, Enrique; Ottaway, David J; López-Higuera, José Miguel; Feng, Xian; Jin, Wei; Jeong, Yoonchan; Picqué, Nathalie; Tong, Limin; Reinhard, Björn M; Pellegrino, Paul M; Méndez, Alexis; Diem, Max; Vollmer, Frank; Quan, Qimin

    2017-08-01

    Sensors are devices or systems able to detect, measure and convert magnitudes from any domain to an electrical one. Using light as a probe for optical sensing is one of the most efficient approaches for this purpose. The history of optical sensing using some methods based on absorbance, emissive and florescence properties date back to the 16th century. The field of optical sensors evolved during the following centuries, but it did not achieve maturity until the demonstration of the first laser in 1960. The unique properties of laser light become particularly important in the case of laser-based sensors, whose operation is entirely based upon the direct detection of laser light itself, without relying on any additional mediating device. However, compared with freely propagating light beams, artificially engineered optical fields are in increasing demand for probing samples with very small sizes and/or weak light-matter interaction. Optical fiber sensors constitute a subarea of optical sensors in which fiber technologies are employed. Different types of specialty and photonic crystal fibers provide improved performance and novel sensing concepts. Actually, structurization with wavelength or subwavelength feature size appears as the most efficient way to enhance sensor sensitivity and its detection limit. This leads to the area of micro- and nano-engineered optical sensors. It is expected that the combination of better fabrication techniques and new physical effects may open new and fascinating opportunities in this area. This roadmap on optical sensors addresses different technologies and application areas of the field. Fourteen contributions authored by experts from both industry and academia provide insights into the current state-of-the-art and the challenges faced by researchers currently. Two sections of this paper provide an overview of laser-based and frequency comb-based sensors. Three sections address the area of optical fiber sensors, encompassing both

  15. Roadmap on optical sensors

    Science.gov (United States)

    Ferreira, Mário F. S.; Castro-Camus, Enrique; Ottaway, David J.; López-Higuera, José Miguel; Feng, Xian; Jin, Wei; Jeong, Yoonchan; Picqué, Nathalie; Tong, Limin; Reinhard, Björn M.; Pellegrino, Paul M.; Méndez, Alexis; Diem, Max; Vollmer, Frank; Quan, Qimin

    2017-08-01

    Sensors are devices or systems able to detect, measure and convert magnitudes from any domain to an electrical one. Using light as a probe for optical sensing is one of the most efficient approaches for this purpose. The history of optical sensing using some methods based on absorbance, emissive and florescence properties date back to the 16th century. The field of optical sensors evolved during the following centuries, but it did not achieve maturity until the demonstration of the first laser in 1960. The unique properties of laser light become particularly important in the case of laser-based sensors, whose operation is entirely based upon the direct detection of laser light itself, without relying on any additional mediating device. However, compared with freely propagating light beams, artificially engineered optical fields are in increasing demand for probing samples with very small sizes and/or weak light-matter interaction. Optical fiber sensors constitute a subarea of optical sensors in which fiber technologies are employed. Different types of specialty and photonic crystal fibers provide improved performance and novel sensing concepts. Actually, structurization with wavelength or subwavelength feature size appears as the most efficient way to enhance sensor sensitivity and its detection limit. This leads to the area of micro- and nano-engineered optical sensors. It is expected that the combination of better fabrication techniques and new physical effects may open new and fascinating opportunities in this area. This roadmap on optical sensors addresses different technologies and application areas of the field. Fourteen contributions authored by experts from both industry and academia provide insights into the current state-of-the-art and the challenges faced by researchers currently. Two sections of this paper provide an overview of laser-based and frequency comb-based sensors. Three sections address the area of optical fiber sensors, encompassing both

  16. Tunnel Magnetoresistance Sensors with Magnetostrictive Electrodes: Strain Sensors

    Directory of Open Access Journals (Sweden)

    Ali Tavassolizadeh

    2016-11-01

    Full Text Available Magnetostrictive tunnel magnetoresistance (TMR sensors pose a bright perspective in micro- and nano-scale strain sensing technology. The behavior of TMR sensors under mechanical stress as well as their sensitivity to the applied stress depends on the magnetization configuration of magnetic tunnel junctions (MTJs with respect to the stress axis. Here, we propose a configuration resulting in an inverse effect on the tunnel resistance by tensile and compressive stresses. Numerical simulations, based on a modified Stoner–Wohlfarth (SW model, are performed in order to understand the magnetization reversal of the sense layer and to find out the optimum bias magnetic field required for high strain sensitivity. At a bias field of −3.2 kA/m under a 0.2 × 10 - 3 strain, gauge factors of 2294 and −311 are calculated under tensile and compressive stresses, respectively. Modeling results are investigated experimentally on a round junction with a diameter of 30 ± 0.2 μ m using a four-point bending apparatus. The measured field and strain loops exhibit nearly the same trends as the calculated ones. Also, the gauge factors are in the same range. The junction exhibits gauge factors of 2150 ± 30 and −260 for tensile and compressive stresses, respectively, under a −3.2 kA/m bias magnetic field. The agreement of the experimental and modeling results approves the proposed configuration for high sensitivity and ability to detect both tensile and compressive stresses by a single TMR sensor.

  17. Scalable Coverage Maintenance for Dense Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Jun Lu

    2007-06-01

    Full Text Available Owing to numerous potential applications, wireless sensor networks have been attracting significant research effort recently. The critical challenge that wireless sensor networks often face is to sustain long-term operation on limited battery energy. Coverage maintenance schemes can effectively prolong network lifetime by selecting and employing a subset of sensors in the network to provide sufficient sensing coverage over a target region. We envision future wireless sensor networks composed of a vast number of miniaturized sensors in exceedingly high density. Therefore, the key issue of coverage maintenance for future sensor networks is the scalability to sensor deployment density. In this paper, we propose a novel coverage maintenance scheme, scalable coverage maintenance (SCOM, which is scalable to sensor deployment density in terms of communication overhead (i.e., number of transmitted and received beacons and computational complexity (i.e., time and space complexity. In addition, SCOM achieves high energy efficiency and load balancing over different sensors. We have validated our claims through both analysis and simulations.

  18. Hall Sensor Output Signal Fault-Detection & Safety Implementation Logic

    Directory of Open Access Journals (Sweden)

    Lee SangHun

    2016-01-01

    Full Text Available Recently BLDC motors have been popular in various industrial applications and electric mobility. Recently BLDC motors have been popular in various industrial applications and electric mobility. In most brushless direct current (BLDC motor drives, there are three hall sensors as a position reference. Low resolution hall effect sensor is popularly used to estimate the rotor position because of its good comprehensive performance such as low cost, high reliability and sufficient precision. Various possible faults may happen in a hall effect sensor. This paper presents a fault-tolerant operation method that allows the control of a BLDC motor with one faulty hall sensor and presents the hall sensor output fault-tolerant control strategy. The situations considered are when the output from a hall sensor stays continuously at low or high levels, or a short-time pulse appears on a hall sensor signal. For fault detection, identification of a faulty signal and generating a substitute signal, this method only needs the information from the hall sensors. There are a few research work on hall effect sensor failure of BLDC motor. The conventional fault diagnosis methods are signal analysis, model based analysis and knowledge based analysis. The proposed method is signal based analysis using a compensation signal for reconfiguration and therefore fault diagnosis can be fast. The proposed method is validated to execute the simulation using PSIM.

  19. An Authentication Protocol for Future Sensor Networks.

    Science.gov (United States)

    Bilal, Muhammad; Kang, Shin-Gak

    2017-04-28

    Authentication is one of the essential security services in Wireless Sensor Networks (WSNs) for ensuring secure data sessions. Sensor node authentication ensures the confidentiality and validity of data collected by the sensor node, whereas user authentication guarantees that only legitimate users can access the sensor data. In a mobile WSN, sensor and user nodes move across the network and exchange data with multiple nodes, thus experiencing the authentication process multiple times. The integration of WSNs with Internet of Things (IoT) brings forth a new kind of WSN architecture along with stricter security requirements; for instance, a sensor node or a user node may need to establish multiple concurrent secure data sessions. With concurrent data sessions, the frequency of the re-authentication process increases in proportion to the number of concurrent connections. Moreover, to establish multiple data sessions, it is essential that a protocol participant have the capability of running multiple instances of the protocol run, which makes the security issue even more challenging. The currently available authentication protocols were designed for the autonomous WSN and do not account for the above requirements. Hence, ensuring a lightweight and efficient authentication protocol has become more crucial. In this paper, we present a novel, lightweight and efficient key exchange and authentication protocol suite called the Secure Mobile Sensor Network (SMSN) Authentication Protocol. In the SMSN a mobile node goes through an initial authentication procedure and receives a re-authentication ticket from the base station. Later a mobile node can use this re-authentication ticket when establishing multiple data exchange sessions and/or when moving across the network. This scheme reduces the communication and computational complexity of the authentication process. We proved the strength of our protocol with rigorous security analysis (including formal analysis using the BAN

  20. Priority image transmission in wireless sensor networks

    International Nuclear Information System (INIS)

    Nasri, M.; Helali, A.; Sghaier, H.; Maaref, H.

    2011-01-01

    The emerging technology during the last years allowed the development of new sensors equipped with wireless communication which can be organized into a cooperative autonomous network. Some application areas for wireless sensor networks (WSNs) are home automations, health care services, military domain, and environment monitoring. The required constraints are limited capacity of processing, limited storage capability, and especially these nodes are limited in energy. In addition, such networks are tiny battery powered which their lifetime is very limited. During image processing and transmission to the destination, the lifetime of sensor network is decreased quickly due to battery and processing power constraints. Therefore, digital image transmissions are a significant challenge for image sensor based Wireless Sensor Networks (WSNs). Based on a wavelet image compression, we propose a novel, robust and energy-efficient scheme, called Priority Image Transmission (PIT) in WSN by providing various priority levels during image transmissions. Different priorities in the compressed image are considered. The information for the significant wavelet coeffcients are transmitted with higher quality assurance, whereas relatively less important coefficients are transmitted with lower overhead. Simulation results show that the proposed scheme prolongs the system lifetime and achieves higher energy efficiency in WSN with an acceptable compromise on the image quality.