An Enhanced Error Model for EKF-Based Tightly-Coupled Integration of GPS and Land Vehicle's Motion Sensors.

Science.gov (United States)

Karamat, Tashfeen B; Atia, Mohamed M; Noureldin, Aboelmagd

2015-09-22

Reduced inertial sensor systems (RISS) have been introduced by many researchers as a low-cost, low-complexity sensor assembly that can be integrated with GPS to provide a robust integrated navigation system for land vehicles. In earlier works, the developed error models were simplified based on the assumption that the vehicle is mostly moving on a flat horizontal plane. Another limitation is the simplified estimation of the horizontal tilt angles, which is based on simple averaging of the accelerometers' measurements without modelling their errors or tilt angle errors. In this paper, a new error model is developed for RISS that accounts for the effect of tilt angle errors and the accelerometer's errors. Additionally, it also includes important terms in the system dynamic error model, which were ignored during the linearization process in earlier works. An augmented extended Kalman filter (EKF) is designed to incorporate tilt angle errors and transversal accelerometer errors. The new error model and the augmented EKF design are developed in a tightly-coupled RISS/GPS integrated navigation system. The proposed system was tested on real trajectories' data under degraded GPS environments, and the results were compared to earlier works on RISS/GPS systems. The findings demonstrated that the proposed enhanced system introduced significant improvements in navigational performance.

An Enhanced Error Model for EKF-Based Tightly-Coupled Integration of GPS and Land Vehicle’s Motion Sensors

Science.gov (United States)

Karamat, Tashfeen B.; Atia, Mohamed M.; Noureldin, Aboelmagd

2015-01-01

Reduced inertial sensor systems (RISS) have been introduced by many researchers as a low-cost, low-complexity sensor assembly that can be integrated with GPS to provide a robust integrated navigation system for land vehicles. In earlier works, the developed error models were simplified based on the assumption that the vehicle is mostly moving on a flat horizontal plane. Another limitation is the simplified estimation of the horizontal tilt angles, which is based on simple averaging of the accelerometers’ measurements without modelling their errors or tilt angle errors. In this paper, a new error model is developed for RISS that accounts for the effect of tilt angle errors and the accelerometer’s errors. Additionally, it also includes important terms in the system dynamic error model, which were ignored during the linearization process in earlier works. An augmented extended Kalman filter (EKF) is designed to incorporate tilt angle errors and transversal accelerometer errors. The new error model and the augmented EKF design are developed in a tightly-coupled RISS/GPS integrated navigation system. The proposed system was tested on real trajectories’ data under degraded GPS environments, and the results were compared to earlier works on RISS/GPS systems. The findings demonstrated that the proposed enhanced system introduced significant improvements in navigational performance. PMID:26402680

GPS-derived coupling estimates for the Central America subduction zone and volcanic arc faults: El Salvador, Honduras and Nicaragua

Science.gov (United States)

Correa-Mora, F.; DeMets, C.; Alvarado, D.; Turner, H. L.; Mattioli, G.; Hernandez, D.; Pullinger, C.; Rodriguez, M.; Tenorio, C.

2009-12-01

We invert GPS velocities from 32 sites in El Salvador, Honduras and Nicaragua to estimate the rate of long-term forearc motion and distributions of interseismic coupling across the Middle America subduction zone offshore from these countries and faults in the Salvadoran and Nicaraguan volcanic arcs. A 3-D finite element model is used to approximate the geometries of the subduction interface and strike-slip faults in the volcanic arc and determine the elastic response to coupling across these faults. The GPS velocities are best fit by a model in which the forearc moves 14-16 mmyr-1 and has coupling of 85-100 per cent across faults in the volcanic arc, in agreement with the high level of historic and recent earthquake activity in the volcanic arc. Our velocity inversion indicates that coupling across the potentially seismogenic areas of the subduction interface is remarkably weak, averaging no more than 3 per cent of the plate convergence rate and with only two poorly resolved patches where coupling might be higher along the 550-km-long segment we modelled. Our geodetic evidence for weak subduction coupling disagrees with a seismically derived coupling estimate of 60 +/- 10 per cent from a published analysis of earthquake damage back to 1690, but agrees with three other seismologic studies that infer weak subduction coupling from 20th century earthquakes. Most large historical earthquakes offshore from El Salvador and western Nicaragua may therefore have been intraslab normal faulting events similar to the Mw 7.3 1982 and Mw 7.7 2001 earthquakes offshore from El Salvador. Alternatively, the degree of coupling might vary with time. The evidence for weak coupling indirectly supports a recently published hypothesis that much of the Middle American forearc is escaping to the west or northwest away from the Cocos Ridge collision zone in Costa Rica. Such a hypothesis is particularly attractive for El Salvador, where there is little or no convergence obliquity to drive the

TESTING ACCURACY THE GPS DEVICES еTrex LEGEND HCx AND еTrex 30 OF THE GARMIN MANUFACTURER

Directory of Open Access Journals (Sweden)

MIHAYLOV Radko

2014-09-01

Full Text Available The object of investigation in this paper is the accuracy of positioning for the two models handheld GPS receivers of the Garmin manufacturer. The world coordinate system WGS84 is used as the base where is obtained the point of positioning. The well known computational method is applied for transforming the obtained latitude, longitude, altitude (LLA coordinates of points to transform toward the coordinates to the Earth-Centred Earth-Fixed (ECEF coordinate system. By the help and the opportunity of mathematical statistics with regression analysis is investigated the accuracy of positioning in vertical and horizontal direction. The comparison and conclusions is made for the accuracy of positioning of the both GPS apparatus.

Hand-held medical robots.

Science.gov (United States)

Payne, Christopher J; Yang, Guang-Zhong

2014-08-01

Medical robots have evolved from autonomous systems to tele-operated platforms and mechanically-grounded, cooperatively-controlled robots. Whilst these approaches have seen both commercial and clinical success, uptake of these robots remains moderate because of their high cost, large physical footprint and long setup times. More recently, researchers have moved toward developing hand-held robots that are completely ungrounded and manipulated by surgeons in free space, in a similar manner to how conventional instruments are handled. These devices provide specific functions that assist the surgeon in accomplishing tasks that are otherwise challenging with manual manipulation. Hand-held robots have the advantages of being compact and easily integrated into the normal surgical workflow since there is typically little or no setup time. Hand-held devices can also have a significantly reduced cost to healthcare providers as they do not necessitate the complex, multi degree-of-freedom linkages that grounded robots require. However, the development of such devices is faced with many technical challenges, including miniaturization, cost and sterility, control stability, inertial and gravity compensation and robust instrument tracking. This review presents the emerging technical trends in hand-held medical robots and future development opportunities for promoting their wider clinical uptake.

GPS-based handheld device for mapping contaminated areas

International Nuclear Information System (INIS)

Paridaens, J.

2005-01-01

Sometimes one is confronted with the challenge to map large areas with enhanced radioactivity. Examples are mine tailings or waste rock piles, deposits of the phosphate industry, flooding zones contaminated by effluents of plants processing ores containing enhanced natural radiation, nuclear accident sites etc. Car borne measuring equipment is not always an option, as the terrain might be rough and only accessible by foot. Airborne mapping with helicopters on the other hand is fast, but expensive, not readily available, shows difficulties with complex topography and lacks the necessary detail. The objective of this study was to create a portable and easily usable tool for the real time logging of radiation and location data, allowing mapping the radioactivity by simply walking over any kind of terrain with the portable equipment and post processing the data in the office. We also assessed the performance of the GPS based system on contaminated sites with areas varying from less than a hectare to several tens of hectares, with respect to speed, precision and ease of use. At sites of large scale mining and processing of uranium ore, tailings and waste rock piles are today the most visible relics of the uranium extractive industry. These mining relics are constantly subjected to weathering and leaching processes causing the dissemination of radioactive and toxic elements and sometimes requiring remedial operations. The in situ remediation of waste rock piles usually includes their revegetation for minimizing the water infiltration and for increasing surface soil stability. Thanks to its biomass density and longevity, the perennial vegetation plays an important role in stabilisation of the water cycling. The buffer role of forest vegetation can reduce water export from watersheds as well as erosion and hydrological losses of chemicals including radionuclides from contaminated sites. If long term reduction of contaminant dispersion at revegetated uranium mining sites is

30 CFR 56.12033 - Hand-held electric tools.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Hand-held electric tools. 56.12033 Section 56.12033 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL....12033 Hand-held electric tools. Hand-held electric tools shall not be operated at high potential...

30 CFR 57.12033 - Hand-held electric tools.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Hand-held electric tools. 57.12033 Section 57.12033 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Surface and Underground § 57.12033 Hand-held electric tools. Hand-held electric tools shall not be...

The use of handheld radiometry for the identification of stratigraphic characteristics of Paraiba Basin units

International Nuclear Information System (INIS)

Souza, Ebenezer Moreno de; Villar, Heldio Pereira; Lima, Ricardo de Andrade; Lima Filho, Mario

2000-01-01

A study on the use of radiometric techniques for the identification of stratigraphic characteristics of Paraiba Basin units was carried out with handheld instrumentation. The area chosen ran from north Pernambuco to south Paraiba. The presence of radioactive material had been previously determined. For this work a portable scintillometer was fixed to the door of a vehicle, on the outside, with the probe directed downwards. Background radiation was measured as 40 cps (counts per second). The scintillometer has an alarm which sounds whenever the measured count rate rises above a pre-established figure, 100 cps in the present case. Monitoring then proceeded manually. In sites where the count rate was much higher than 100 cps, the probe was lowered to the soil surface. Local coordinates were obtained by GPS. Therefore, an isoradioactivity map of the area could be drawn. The comparison between this map and local geological charts showed significant correlation between observed count rates and geologic formations. Low count rates were indicative of the Barreiras formation, whereas the highest rates were obtained for the Gramame formation (with urano-phosphatic lythotypes). It is concluded that handheld radiometry is a useful tool in geological charting, is special in areas where stratigraphic units have been masked by environmental changes and human activities. (author)

Correcting for motion artifact in handheld laser speckle images

Science.gov (United States)

Lertsakdadet, Ben; Yang, Bruce Y.; Dunn, Cody E.; Ponticorvo, Adrien; Crouzet, Christian; Bernal, Nicole; Durkin, Anthony J.; Choi, Bernard

2018-03-01

Laser speckle imaging (LSI) is a wide-field optical technique that enables superficial blood flow quantification. LSI is normally performed in a mounted configuration to decrease the likelihood of motion artifact. However, mounted LSI systems are cumbersome and difficult to transport quickly in a clinical setting for which portability is essential in providing bedside patient care. To address this issue, we created a handheld LSI device using scientific grade components. To account for motion artifact of the LSI device used in a handheld setup, we incorporated a fiducial marker (FM) into our imaging protocol and determined the difference between highest and lowest speckle contrast values for the FM within each data set (Kbest and Kworst). The difference between Kbest and Kworst in mounted and handheld setups was 8% and 52%, respectively, thereby reinforcing the need for motion artifact quantification. When using a threshold FM speckle contrast value (KFM) to identify a subset of images with an acceptable level of motion artifact, mounted and handheld LSI measurements of speckle contrast of a flow region (KFLOW) in in vitro flow phantom experiments differed by 8%. Without the use of the FM, mounted and handheld KFLOW values differed by 20%. To further validate our handheld LSI device, we compared mounted and handheld data from an in vivo porcine burn model of superficial and full thickness burns. The speckle contrast within the burn region (KBURN) of the mounted and handheld LSI data differed by burns. Collectively, our results suggest the potential of handheld LSI with an FM as a suitable alternative to mounted LSI, especially in challenging clinical settings with space limitations such as the intensive care unit.

Developing a compact multiple laser diode combiner with a single fiber stub output for handheld IoT devices

Science.gov (United States)

Lee, Minseok; June, Seunghyeok; Kim, Sehwan

2018-01-01

Many biomedical applications require an efficient combination and localization of multiple discrete light sources ( e.g., fluorescence and absorbance imaging). We present a compact 6 channel combiner that couples the output of independent solid-state light sources into a single 400-μm-diameter fiber stub for handheld Internet of Things (IoT) devices. We demonstrate average coupling efficiencies > 80% for each of the 6 laser diodes installed into the prototype. The design supports the use of continuous wave and intensity-modulated laser diodes. This fiber-stub-type beam combiner could be used to construct custom multi-wavelength sources for tissue oximeters, microscopes and molecular imaging technologies. In order to validate its suitability, we applied the developed fiber-stub-type beam combiner to a multi-wavelength light source for a handheld IoT device and demonstrated its feasibility for smart healthcare through a tumor-mimicking silicon phantom.

ENGAGING SCIENCE STUDENTS WITH HANDHELD TECHNOLOGY AND APPLICATIONS BY RE-VISITING THE THAYER METHOD OF TEACHING AND LEARNING

Directory of Open Access Journals (Sweden)

Julia Paredes

2011-12-01

Full Text Available Organic chemistry instructors integrate handheld technology and applications into course lecture and lab to engage students with tools and techniques students use in the modern world. This technology and applications enable instructors to re-visit the Thayer Method of teaching and learning to create an updated method that works with 21st century students. The Thayer Method is based on the premise that students are willing and capable of making substantial preparation before coming to class and lab in order to maximize efficiency of student-instructor contact time. During this student preparation phase, we engage students with handheld technology and content applications including smart phone viewable course administrative materials; “flashcards” containing basic organic chemistry nomenclature, molecular structures, and chemical reactions; mini-lectures prepared using the Smart Board Airliner Interactive Tablet for upcoming class periods and laboratory technique videos demonstrating tasks they will perform as part of laboratory experimentation. Coupled with a student friendly course text, these handheld applications enable substantial student preparation before class and lab. The method, in conjunction with handheld technology and applications, has been used with positive results in our organic chemistry courses.

Image Quality Characteristics of Handheld Display Devices for Medical Imaging

Science.gov (United States)

Yamazaki, Asumi; Liu, Peter; Cheng, Wei-Chung; Badano, Aldo

2013-01-01

Handheld devices such as mobile phones and tablet computers have become widespread with thousands of available software applications. Recently, handhelds are being proposed as part of medical imaging solutions, especially in emergency medicine, where immediate consultation is required. However, handheld devices differ significantly from medical workstation displays in terms of display characteristics. Moreover, the characteristics vary significantly among device types. We investigate the image quality characteristics of various handheld devices with respect to luminance response, spatial resolution, spatial noise, and reflectance. We show that the luminance characteristics of the handheld displays are different from those of workstation displays complying with grayscale standard target response suggesting that luminance calibration might be needed. Our results also demonstrate that the spatial characteristics of handhelds can surpass those of medical workstation displays particularly for recent generation devices. While a 5 mega-pixel monochrome workstation display has horizontal and vertical modulation transfer factors of 0.52 and 0.47 at the Nyquist frequency, the handheld displays released after 2011 can have values higher than 0.63 at the respective Nyquist frequencies. The noise power spectra for workstation displays are higher than 1.2×10−5 mm2 at 1 mm−1, while handheld displays have values lower than 3.7×10−6 mm2. Reflectance measurements on some of the handheld displays are consistent with measurements for workstation displays with, in some cases, low specular and diffuse reflectance coefficients. The variability of the characterization results among devices due to the different technological features indicates that image quality varies greatly among handheld display devices. PMID:24236113

PALMARI GPS INTEGRATI NELLA GESTIONE DEL VERDE DI MILANO Un sistema di controllo della qualità a supporto della pianificazione

Directory of Open Access Journals (Sweden)

Franco Guzzetti

2013-10-01

Full Text Available Green public spaces within cities are preciousresources that have to be safeguarded andenhanced as public assets with an importantenvironmental and social role. The municipalityof Milano has developed a GIS-basedmanagement system, which allows managing,monitoring and documenting all maintenanceactivities, while ensuring an agreedlevel of quality. The activities are carriedout by external companies, in the frameworkof a Global Service. In order to monitorthe quality of green areas, municipal controllersand operators in the field monitorquality standards and report non compliancecases using handheld GPS devices. Thegeo-referenced reports are then matchedwith the elements in the GIS and forwardedto the gardeners in charge of the area. Thisarticle analyses the result of one year of useof GPS devices in the field, the problems encountered,and the improvements made in theoverall green area management in the Cityof Milano.

Wireless Handhelds to Support Clinical Nursing Practicum

Science.gov (United States)

Wu, Cheng-Chih; Lai, Chin-Yuan

2009-01-01

This paper reports our implementation and evaluation of a wireless handheld learning environment used to support a clinical nursing practicum course. The learning environment was designed so that nursing students could use handhelds for recording information, organizing ideas, assessing patients, and also for interaction and collaboration with…

75 FR 8928 - Announcement of IS-GPS-200, IS-GPS-705, IS-GPS-800 Interface Control Working Group (ICWG...

Science.gov (United States)

2010-02-26

... DEPARTMENT OF DEFENSE Department of the Air Force Announcement of IS-GPS-200, IS-GPS-705, IS-GPS... document/s IS-GPS-200E (NAVSTAR GPS Space Segment/Navigation User Interfaces), IS-GPS-705A (NAVSTAR GPS Space Segment/User Segment L5 Interfaces), and IS-GPS-800A (NAVSTAR GPS Space Segment/User Segment L1C...

Geophysics and Texas History: Teachers Utilize GPS and GPR Technology to Help Restore an Abandoned Cemetery

Science.gov (United States)

Henning, A. T.; Sawyer, D. S.; Wallace, D.; Kahera, A.

2009-12-01

In July 2009, a group of twenty-six K-12 teachers investigated an abandoned cemetery in Prairie View, Texas, utilizing ground-penetrating radar (GPR) to image the subsurface and handheld global positioning system (GPS) units and a total station to record surface positions. The teachers were participants in a summer course at Rice University, ESCI 515: Geophysical Field Work for Educators. The course met for 8 full days over a two week period. During this time, the group acquired and interpreted 53 GPR profiles and over 700 GPS positions. The results of the study were presented to the Prairie View community at the end of the two weeks, and our data will be used in their effort to obtain a historical site designation for the cemetery. Wyatt Chapel Cemetery is located adjacent to the campus of Prairie View A&M University in Prairie View, TX, and is thought to have originated as a slave burial ground in the 1850’s. There are very few markers remaining, but a previous ESCI 515 course (in summer 2007) discovered multiple unmarked burials using GPR, which were confirmed by subsequent excavations. This past summer, ESCI 515 participants acquired GPR profiles in previously unexplored areas, used a total station to accurately record the positions of surface features such as headstones, and used handheld GPS units to map the location of a nearby stream bed. Participants were in-service K-12 teachers from urban Houston school districts where the majority of students are members of historically underrepresented minority groups. Recruitment efforts targeted educators who are currently teaching science without a science degree. Participants included elementary, middle and high school teachers. This summer experience is followed by a content-intensive academic year course in Physical Geology. Participants experienced the process of science first-hand and used science for community service (i.e. restoring an abandoned cemetery). Through background research, they derived a rich

Hacking GPS

CERN Document Server

Kingsley-Hughes, Kathie

2005-01-01

* This is the "user manual" that didn't come with any of the 30 million GPS receivers currently in use, showing readers how to modify, tweak, and hack their GPS to take it to new levels!* Crazy-cool modifications include exploiting secret keycodes, revealing hidden features, building power cords and cables, hacking the battery and antenna, protecting a GPS from impact and falls, making a screen protector, and solar-powering a GPS* Potential power users will take the function and performance of their GPS to a whole new level by hacking into the firmware and hacking into a PC connection with a GPS* Fear not! Any potentially dangerous mod (to the device) is clearly labeled, with precautions listed that should be taken* Game time! Readers can check out GPS games, check into hacking geocaching, and even use a GPS as a metal detector

The Aalborg Survey / Part 2 - GPS Based Survey

DEFF Research Database (Denmark)

Harder, Henrik; Reiter, Ida Maria; Christensen, Cecilie Breinholm

, the GPS based data are supplemented with an attractivity analysis among the 169 respondents. The resulting data are presented in maps in three scales that illustrate the respondents’ use of Aalborg’s urban spaces with regards to the respondent’s movements in time and space. By further coupling the GPS...... data with data on the single respondent’s gender, age, address, activities, mode of transport, use of money etc. it is possible to gain a more detailed knowledge of young people’s use of urban spaces in Aalborg....

ITSY Handheld Software Radio

National Research Council Canada - National Science Library

Bose, Vanu

2001-01-01

.... A handheld software radio platform would enable the construction of devices that could inter-operate with multiple legacy systems, download new waveforms and be used to construct adhoc networks...

Determination of locational error associated with global positioning system (GPS) radio collars in relation to vegetation and topography in north-central New Mexico

Energy Technology Data Exchange (ETDEWEB)

Bennett, K.; Biggs, J.; Fresquez, P.R.

1997-02-01

In 1996, a study was initiated to assess seasonal habitat use and movement patterns of Rocky Mountain elk (Cervus elaphus nelsoni) using global positioning system (GPS) radio collars. As part of this study, the authors attempted to assess the accuracies of GPS (non-differentially corrected) positions under various vegetation canopies and terrain conditions with the use of a GPS ``test`` collar. The test collar was activated every twenty minutes to obtain a position location and continuously uplinked to Argos satellites to transfer position data files. They used a Telonics, Inc. uplink receiver to intercept the transmission and view the results of the collar in real time. They placed the collar on a stand equivalent to the neck height of an adult elk and then placed the stand within three different treatment categories: (1) topographical influence (canyon and mesa tops), (2) canopy influence (open and closed canopy), and (3) vegetation type influence (ponderosa pine and pinion pine-juniper). The collar was kept at each location for one hour (usually obtaining three fixes). In addition, the authors used a hand-held GPS to obtain a position of the test collar at the same time and location.

Integrated navigation of aerial robot for GPS and GPS-denied environment

International Nuclear Information System (INIS)

Suzuki, Satoshi; Min, Hongkyu; Nonami, Kenzo; Wada, Tetsuya

2016-01-01

In this study, novel robust navigation system for aerial robot in GPS and GPS- denied environments is proposed. Generally, the aerial robot uses position and velocity information from Global Positioning System (GPS) for guidance and control. However, GPS could not be used in several environments, for example, GPS has huge error near buildings and trees, indoor, and so on. In such GPS-denied environment, Laser Detection and Ranging (LIDER) sensor based navigation system have generally been used. However, LIDER sensor also has an weakness, and it could not be used in the open outdoor environment where GPS could be used. Therefore, it is desired to develop the integrated navigation system which is seamlessly applied to GPS and GPS-denied environments. In this paper, the integrated navigation system for aerial robot using GPS and LIDER is developed. The navigation system is designed based on Extended Kalman Filter, and the effectiveness of the developed system is verified by numerical simulation and experiment. (paper)

GPS Composite Clock Analysis

OpenAIRE

Wright, James R.

2008-01-01

The GPS composite clock defines GPS time, the timescale used today in GPS operations. GPS time is illuminated by examination of its role in the complete estimation and control problem relative to UTC/TAI. The phase of each GPS clock is unobservable from GPS pseudorange measurements, and the mean phase of the GPS clock ensemble (GPS time) is unobservable. A new and useful observability definition is presented, together with new observability theorems, to demonstrate explicitly that GPS time is...

Introduction of handheld computing to a family practice residency program.

Science.gov (United States)

Rao, Goutham

2002-01-01

Handheld computers are valuable practice tools. It is important for residency programs to introduce their trainees and faculty to this technology. This article describes a formal strategy to introduce handheld computing to a family practice residency program. Objectives were selected for the handheld computer training program that reflected skills physicians would find useful in practice. TRGpro handheld computers preloaded with a suite of medical reference programs, a medical calculator, and a database program were supplied to participants. Training consisted of four 1-hour modules each with a written evaluation quiz. Participants completed a self-assessment questionnaire after the program to determine their ability to meet each objective. Sixty of the 62 participants successfully completed the training program. The mean composite score on quizzes was 36 of 40 (90%), with no significant differences by level of residency training. The mean self-ratings of participants across all objectives was 3.31 of 4.00. Third-year residents had higher mean self-ratings than others (mean of group, 3.62). Participants were very comfortable with practical skills, such as using drug reference software, and less comfortable with theory, such as knowing the different types of handheld computers available. Structured training is a successful strategy for introducing handheld computing to a residency program.

Navigating on handheld displays: Dynamic versus Static Keyhole Navigation

NARCIS (Netherlands)

Mehra, S.; Werkhoven, P.; Worring, M.

2006-01-01

Handheld displays leave little space for the visualization and navigation of spatial layouts representing rich information spaces. The most common navigation method for handheld displays is static peephole navigation: The peephole is static and we move the spatial layout behind it (scrolling). A

Doctors' experience with handheld computers in clinical practice: qualitative study.

Science.gov (United States)

McAlearney, Ann Scheck; Schweikhart, Sharon B; Medow, Mitchell A

2004-05-15

To examine doctors' perspectives about their experiences with handheld computers in clinical practice. Qualitative study of eight focus groups consisting of doctors with diverse training and practice patterns. Six practice settings across the United States and two additional focus group sessions held at a national meeting of general internists. 54 doctors who did or did not use handheld computers. Doctors who used handheld computers in clinical practice seemed generally satisfied with them and reported diverse patterns of use. Users perceived that the devices helped them increase productivity and improve patient care. Barriers to use concerned the device itself and personal and perceptual constraints, with perceptual factors such as comfort with technology, preference for paper, and the impression that the devices are not easy to use somewhat difficult to overcome. Participants suggested that organisations can help promote handheld computers by providing advice on purchase, usage, training, and user support. Participants expressed concern about reliability and security of the device but were particularly concerned about dependency on the device and over-reliance as a substitute for clinical thinking. Doctors expect handheld computers to become more useful, and most seem interested in leveraging (getting the most value from) their use. Key opportunities with handheld computers included their use as a stepping stone to build doctors' comfort with other information technology and ehealth initiatives and providing point of care support that helps improve patient care.

Combined GPS/GLONASS Precise Point Positioning with Fixed GPS Ambiguities

Science.gov (United States)

Pan, Lin; Cai, Changsheng; Santerre, Rock; Zhu, Jianjun

2014-01-01

Precise point positioning (PPP) technology is mostly implemented with an ambiguity-float solution. Its performance may be further improved by performing ambiguity-fixed resolution. Currently, the PPP integer ambiguity resolutions (IARs) are mainly based on GPS-only measurements. The integration of GPS and GLONASS can speed up the convergence and increase the accuracy of float ambiguity estimates, which contributes to enhancing the success rate and reliability of fixing ambiguities. This paper presents an approach of combined GPS/GLONASS PPP with fixed GPS ambiguities (GGPPP-FGA) in which GPS ambiguities are fixed into integers, while all GLONASS ambiguities are kept as float values. An improved minimum constellation method (MCM) is proposed to enhance the efficiency of GPS ambiguity fixing. Datasets from 20 globally distributed stations on two consecutive days are employed to investigate the performance of the GGPPP-FGA, including the positioning accuracy, convergence time and the time to first fix (TTFF). All datasets are processed for a time span of three hours in three scenarios, i.e., the GPS ambiguity-float solution, the GPS ambiguity-fixed resolution and the GGPPP-FGA resolution. The results indicate that the performance of the GPS ambiguity-fixed resolutions is significantly better than that of the GPS ambiguity-float solutions. In addition, the GGPPP-FGA improves the positioning accuracy by 38%, 25% and 44% and reduces the convergence time by 36%, 36% and 29% in the east, north and up coordinate components over the GPS-only ambiguity-fixed resolutions, respectively. Moreover, the TTFF is reduced by 27% after adding GLONASS observations. Wilcoxon rank sum tests and chi-square two-sample tests are made to examine the significance of the improvement on the positioning accuracy, convergence time and TTFF. PMID:25237901

Combined GPS/GLONASS Precise Point Positioning with Fixed GPS Ambiguities

Directory of Open Access Journals (Sweden)

Lin Pan

2014-09-01

Full Text Available Precise point positioning (PPP technology is mostly implemented with an ambiguity-float solution. Its performance may be further improved by performing ambiguity-fixed resolution. Currently, the PPP integer ambiguity resolutions (IARs are mainly based on GPS-only measurements. The integration of GPS and GLONASS can speed up the convergence and increase the accuracy of float ambiguity estimates, which contributes to enhancing the success rate and reliability of fixing ambiguities. This paper presents an approach of combined GPS/GLONASS PPP with fixed GPS ambiguities (GGPPP-FGA in which GPS ambiguities are fixed into integers, while all GLONASS ambiguities are kept as float values. An improved minimum constellation method (MCM is proposed to enhance the efficiency of GPS ambiguity fixing. Datasets from 20 globally distributed stations on two consecutive days are employed to investigate the performance of the GGPPP-FGA, including the positioning accuracy, convergence time and the time to first fix (TTFF. All datasets are processed for a time span of three hours in three scenarios, i.e., the GPS ambiguity-float solution, the GPS ambiguity-fixed resolution and the GGPPP-FGA resolution. The results indicate that the performance of the GPS ambiguity-fixed resolutions is significantly better than that of the GPS ambiguity-float solutions. In addition, the GGPPP-FGA improves the positioning accuracy by 38%, 25% and 44% and reduces the convergence time by 36%, 36% and 29% in the east, north and up coordinate components over the GPS-only ambiguity-fixed resolutions, respectively. Moreover, the TTFF is reduced by 27% after adding GLONASS observations. Wilcoxon rank sum tests and chi-square two-sample tests are made to examine the significance of the improvement on the positioning accuracy, convergence time and TTFF.

Relationships between GPS-signal propagation errors and EISCAT observations

Directory of Open Access Journals (Sweden)

N. Jakowski

1996-12-01

Full Text Available When travelling through the ionosphere the signals of space-based radio navigation systems such as the Global Positioning System (GPS are subject to modifications in amplitude, phase and polarization. In particular, phase changes due to refraction lead to propagation errors of up to 50 m for single-frequency GPS users. If both the L1 and the L2 frequencies transmitted by the GPS satellites are measured, first-order range error contributions of the ionosphere can be determined and removed by difference methods. The ionospheric contribution is proportional to the total electron content (TEC along the ray path between satellite and receiver. Using about ten European GPS receiving stations of the International GPS Service for Geodynamics (IGS, the TEC over Europe is estimated within the geographic ranges -20°≤ λ ≤40°E and 32.5°≤ Φ ≤70°N in longitude and latitude, respectively. The derived TEC maps over Europe contribute to the study of horizontal coupling and transport proces- ses during significant ionospheric events. Due to their comprehensive information about the high-latitude ionosphere, EISCAT observations may help to study the influence of ionospheric phenomena upon propagation errors in GPS navigation systems. Since there are still some accuracy limiting problems to be solved in TEC determination using GPS, data comparison of TEC with vertical electron density profiles derived from EISCAT observations is valuable to enhance the accuracy of propagation-error estimations. This is evident both for absolute TEC calibration as well as for the conversion of ray-path-related observations to vertical TEC. The combination of EISCAT data and GPS-derived TEC data enables a better understanding of large-scale ionospheric processes.

Compact printed two dipole array antenna with a high front-back ratio for ultra-high-frequency radio-frequency identification handheld reader applications

DEFF Research Database (Denmark)

Liu, Qi; Zhang, Shuai; He, Sailing

2015-01-01

A printed two-dipole array antenna with a high front-back ratio is proposed for ultra-high-frequency (UHF) radio-frequency identification handheld readers. The proposed antenna is a parasitic dual-element array with the ends of both elements folded back towards each other for additional coupling....

A Real-Time Capable Software-Defined Receiver Using GPU for Adaptive Anti-Jam GPS Sensors

Science.gov (United States)

Seo, Jiwon; Chen, Yu-Hsuan; De Lorenzo, David S.; Lo, Sherman; Enge, Per; Akos, Dennis; Lee, Jiyun

2011-01-01

Due to their weak received signal power, Global Positioning System (GPS) signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference and jamming. Since adaptive array processing requires intensive computational power, beamsteering GPS receivers were usually implemented using hardware such as field-programmable gate arrays (FPGAs). However, a software implementation using general-purpose processors is much more desirable because of its flexibility and cost effectiveness. This paper presents a GPS software-defined radio (SDR) with adaptive beamsteering capability for anti-jam applications. The GPS SDR design is based on an optimized desktop parallel processing architecture using a quad-core Central Processing Unit (CPU) coupled with a new generation Graphics Processing Unit (GPU) having massively parallel processors. This GPS SDR demonstrates sufficient computational capability to support a four-element antenna array and future GPS L5 signal processing in real time. After providing the details of our design and optimization schemes for future GPU-based GPS SDR developments, the jamming resistance of our GPS SDR under synthetic wideband jamming is presented. Since the GPS SDR uses commercial-off-the-shelf hardware and processors, it can be easily adopted in civil GPS applications requiring anti-jam capabilities. PMID:22164116

A Real-Time Capable Software-Defined Receiver Using GPU for Adaptive Anti-Jam GPS Sensors

Directory of Open Access Journals (Sweden)

Dennis Akos

2011-09-01

Full Text Available Due to their weak received signal power, Global Positioning System (GPS signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference and jamming. Since adaptive array processing requires intensive computational power, beamsteering GPS receivers were usually implemented using hardware such as field-programmable gate arrays (FPGAs. However, a software implementation using general-purpose processors is much more desirable because of its flexibility and cost effectiveness. This paper presents a GPS software-defined radio (SDR with adaptive beamsteering capability for anti-jam applications. The GPS SDR design is based on an optimized desktop parallel processing architecture using a quad-core Central Processing Unit (CPU coupled with a new generation Graphics Processing Unit (GPU having massively parallel processors. This GPS SDR demonstrates sufficient computational capability to support a four-element antenna array and future GPS L5 signal processing in real time. After providing the details of our design and optimization schemes for future GPU-based GPS SDR developments, the jamming resistance of our GPS SDR under synthetic wideband jamming is presented. Since the GPS SDR uses commercial-off-the-shelf hardware and processors, it can be easily adopted in civil GPS applications requiring anti-jam capabilities.

Data for Users of Handheld Ion Mobility Spectrometers

International Nuclear Information System (INIS)

Keith A. Daum; Sandra L. Fox

2008-01-01

Chemical detection technology end-user surveys conducted by Idaho National Laboratory (INL) in 2005 and 2007 indicated that first responders believed manufacturers claims for instruments sometimes were not supported in field applications, and instruments sometimes did not meet their actual needs. Based on these findings, the Department of Homeland Security (DHS) asked INL to conduct a similar survey for handheld ion mobility spectrometers (IMS), which are used by a broad community of first responders as well as for other applications. To better access this broad community, the INL used the Center for Technology Commercialization, Inc. (CTC), Public Safety Technology Center (PSTC) to set up an online framework to gather information from users of handheld IMS units. This framework (Survey Monkey) was then used to perform an online Internet survey, augmented by e-mail prompts, to get information from first responders and personnel from various agencies about their direct experience with handheld IMS units. Overall, 478 individuals responded to the survey. Of these, 174 respondents actually owned a handheld IMS. Performance and satisfaction data from these 174 respondents are captured in this report. The survey identified the following observations: (1) The most common IMS unit used by respondents was the Advanced Portable Detector (APD 2000), followed by ChemRae, Sabre 4000, Sabre 2000, Draeger Multi IMS, Chemical Agent Monitor-2, Chemical Agent Monitor, Vapor Tracer, and Vapor Tracer 2. (2) The primary owners were HazMat teams (20%), fire services (14%), local police (12%), and sheriffs departments (9%). (3) IMS units are seldom used as part of an integrated system for detecting and identifying chemicals but instead are used independently. (4) Respondents are generally confused about the capabilities of their IMS unit. This is probably a result of lack of training. (5) Respondents who had no training or fewer than 8 hours were not satisfied with the overall operation

Electronic prescribing: criteria for evaluating handheld prescribing systems and an evaluation of a new, handheld, wireless wide area network (WWAN) prescribing system.

Science.gov (United States)

Goldblum, O M

2001-02-01

The objectives of this study were: 1) to establish criteria for evaluating handheld computerized prescribing systems; and 2) to evaluate out-of-box performance and features of a new, Palm Operating System (OS)-based, handheld, wireless wide area network (WWAN) prescribing system. The system consisted of a Palm Vx handheld organizer, a Novatel Minstrel V wireless modem, OmniSky wireless internet access and ePhysician ePad 1.1, the Palm OS electronic prescribing software program. A dermatologist familiar with healthcare information technology conducted an evaluation of the performance and features of a new, handheld, WWAN electronic prescribing system in an office practice during a three-month period in 2000. System performance, defined as transmission success rate, was determined from data collected during the three-month trial. Evaluation criteria consisted of an analysis of features found in electronic prescribing systems. All prescriptions written for all patients seen during a three-month period (August - November, 2000) were eligible for inclusion. Prescriptions written for patients who intended to fill them at pharmacies without known facsimile receiving capabilities were excluded from the study. The performance of the system was evaluated using data collected during the study. Criteria for evaluating features of electronic prescribing systems were developed and used to analyze the system employed in this study. During this three-month trial, 200 electronic prescriptions were generated for 132 patients included in the study. Of these prescriptions, 92.5 percent were successfully transmitted to pharmacies. Transmission failures resulted from incorrect facsimile numbers and non-functioning facsimile machines. Criteria established for evaluation of electronic prescribing systems included System (Hardware & Software), Costs, System Features, Printing & Transmission, Formulary & Insurance, Customization, Drug Safety and Security. This study is the first effort to

Handheld Microfluidic Blood Ananlyzer, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Nanohmics proposes to develop a handheld blood analyzer for micro- and hypo-gravity missions. The prototype instrument will combine impedance analysis with optical...

Handheld CAT Video Game, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The proposed project is to design, develop and fabricate a handheld video game console for astronauts during long space flight. This portable hardware runs...

A Cognitive Style Perspective to Handheld Devices: Customization vs. Personalization

Science.gov (United States)

Hsieh, Chen-Wei; Chen, Sherry Y.

2016-01-01

Handheld devices are widely applied to support open and distributed learning, where students are diverse. On the other hand, customization and personalization can be applied to accommodate students' diversities. However, paucity of research compares the effects of customization and personalization in the context of handheld devices. To this end, a…

Benefits of Combined GPS/GLONASS with Low-Cost MEMS IMUs for Vehicular Urban Navigation

Directory of Open Access Journals (Sweden)

Giovanni Pugliano

2012-04-01

Full Text Available The integration of Global Navigation Satellite Systems (GNSS with Inertial Navigation Systems (INS has been very actively researched for many years due to the complementary nature of the two systems. In particular, during the last few years the integration with micro-electromechanical system (MEMS inertial measurement units (IMUs has been investigated. In fact, recent advances in MEMS technology have made possible the development of a new generation of low cost inertial sensors characterized by small size and light weight, which represents an attractive option for mass-market applications such as vehicular and pedestrian navigation. However, whereas there has been much interest in the integration of GPS with a MEMS-based INS, few research studies have been conducted on expanding this application to the revitalized GLONASS system. This paper looks at the benefits of adding GLONASS to existing GPS/INS(MEMS systems using loose and tight integration strategies. The relative benefits of various constraints are also assessed. Results show that when satellite visibility is poor (approximately 50% solution availability the benefits of GLONASS are only seen with tight integration algorithms. For more benign environments, a loosely coupled GPS/GLONASS/INS system offers performance comparable to that of a tightly coupled GPS/INS system, but with reduced complexity and development time.

Benefits of combined GPS/GLONASS with low-cost MEMS IMUs for vehicular urban navigation.

Science.gov (United States)

Angrisano, Antonio; Petovello, Mark; Pugliano, Giovanni

2012-01-01

The integration of Global Navigation Satellite Systems (GNSS) with Inertial Navigation Systems (INS) has been very actively researched for many years due to the complementary nature of the two systems. In particular, during the last few years the integration with micro-electromechanical system (MEMS) inertial measurement units (IMUs) has been investigated. In fact, recent advances in MEMS technology have made possible the development of a new generation of low cost inertial sensors characterized by small size and light weight, which represents an attractive option for mass-market applications such as vehicular and pedestrian navigation. However, whereas there has been much interest in the integration of GPS with a MEMS-based INS, few research studies have been conducted on expanding this application to the revitalized GLONASS system. This paper looks at the benefits of adding GLONASS to existing GPS/INS(MEMS) systems using loose and tight integration strategies. The relative benefits of various constraints are also assessed. Results show that when satellite visibility is poor (approximately 50% solution availability) the benefits of GLONASS are only seen with tight integration algorithms. For more benign environments, a loosely coupled GPS/GLONASS/INS system offers performance comparable to that of a tightly coupled GPS/INS system, but with reduced complexity and development time.

Contact lens assisted imaging with integrated flexible handheld probe for glaucoma diagnosis

Science.gov (United States)

Hong, Xun Jie Jeesmond; V. K., Shinoj; Murukeshan, V. M.; Baskaran, M.; Aung, Tin

2017-06-01

Angle closure glaucoma accounts for majority of the bilateral blindness in Asian countries such as Singapore, China, and India. Abnormalities in the optic nerve and aqueous outflow system are the most indicative clinical hallmarks for glaucoma of this clinical subtype. Traditional photographic imaging techniques to assess the drainage angle are contact based, and may expose patients to risk of corneal abrasion and infections. In addition, these procedures require the use of viscous ophthalmic gels as coupling medium to overcome the phenomenon of total internal reflection at the tear-air interface. In this paper, we propose an integrated flexible handheld probe consisting of a micro color CCD video camera and white light LEDs. The handheld probe is able to capture images of the fundus and opposite iridocorneal angle when placed at the central cornea or limbus respectively. Here, we propose the use of hydrogel contact lens as an index matching medium and better protective barrier, as an alternative to conventional ophthalmic gels. The proposed imaging system and methodology has been successfully tested on porcine eye samples, ex vivo. With its high repeatability, reproducibility, and a good safety profile, it is believed that the proposed imaging system and methodology will complement existing imaging modalities in the diagnosis and management of glaucoma.

GPS phase scintillation and auroral electrojet currents during geomagnetic storms of March 17, 2013 and 2015

DEFF Research Database (Denmark)

Prikryl, P.; Ghoddousi-Fard, R.; Viljanen, A.

2017-01-01

in the context of solar wind coupling to the magnetosphere-ionosphere system. Phase scintillation is observed at high latitudes by arrays of high-rate GNSS Ionospheric Scintillation and TEC Monitors (GISTMs) and geodetic-quality GPS receivers sampling at 1 Hz. The high-rate GPS receivers are distributed...... in the northern and in the southern high latitudes with sparser coverage. In addition to GPS receivers, the high-latitude ionosphere dynamics is studied using arrays of ground-based instruments including HF radars, ionosondes, riometers, magnetometers, optical imagers as well as particle detectors and ultraviolet...

Characterizing the reflectivity of handheld display devices.

Science.gov (United States)

Liu, Peter; Badano, Aldo

2014-08-01

With increased use of handheld and tablet display devices for viewing medical images, methods for consistently measuring reflectivity of the devices are needed. In this note, the authors report on the characterization of diffuse reflections for handheld display devices including mobile phones and tablets using methods recommended by the American Association of Physicists in Medicine Task Group 18 (TG18). The authors modified the diffuse reflectance coefficient measurement method outlined in the TG18 report. The authors measured seven handheld display devices (two phones and five tablets) and three workstation displays. The device was attached to a black panel with Velcro. To study the effect of the back surface on the diffuse reflectance coefficient, the authors created Styrofoam masks with different size square openings and placed it in front of the device. Overall, for each display device, measurements of illuminance and reflected luminance on the display screen were taken. The authors measured with no mask, with masks of varying size, and with display-size masks, and calculated the corresponding diffuse reflectance coefficient. For all handhelds, the diffuse reflectance coefficient measured with no back panel were lower than measurements performed with a mask. The authors found an overall increase in reflectivity as the size of the mask decreases. For workstations displays, diffuse reflectance coefficients were higher when no back panel was used, and higher than with masks. In all cases, as luminance increased, illuminance increased, but not at the same rate. Since the size of handheld displays is smaller than that of workstation devices, the TG18 method suffers from a dependency on illumination condition. The authors show that the diffuse reflection coefficients can vary depending on the nature of the back surface of the illuminating box. The variability in the diffuse coefficient can be as large as 20% depending on the size of the mask. For all measurements

Remote landslide mapping using a laser rangefinder binocular and GPS

Directory of Open Access Journals (Sweden)

M. Santangelo

2010-12-01

Full Text Available We tested a high-quality laser rangefinder binocular coupled with a GPS receiver connected to a Tablet PC running dedicated software to help recognize and map in the field recent rainfall-induced landslides. The system was tested in the period between March and April 2010, in the Monte Castello di Vibio area, Umbria, Central Italy. To test the equipment, we measured thirteen slope failures that were mapped previously during a visual reconnaissance field campaign conducted in February and March 2010. For reference, four slope failures were also mapped by walking the GPS receiver along the landslide perimeter. Comparison of the different mappings revealed that the geographical information obtained remotely for each landslide by the rangefinder binocular and GPS was comparable to the information obtained by walking the GPS around the landslide perimeter, and was superior to the information obtained through the visual reconnaissance mapping. Although our tests were not exhaustive, we maintain that the system is effective to map recent rainfall induced landslides in the field, and we foresee the possibility of using the same (or similar system to map landslides, and other geomorphological features, in other areas.

Driver hand-held cellular phone use: a four-year analysis.

Science.gov (United States)

Eby, David W; Vivoda, Jonathon M; St Louis, Renée M

2006-01-01

The use of hand-held cellular (mobile) phones while driving has stirred more debate, passion, and research than perhaps any other traffic safety issue in the past several years. There is ample research showing that the use of either hand-held or hands-free cellular phones can lead to unsafe driving patterns. Whether or not these performance deficits increase the risk of crash is difficult to establish, but recent studies are beginning to suggest that cellular phone use elevates crash risk. The purpose of this study was to assess changes in the rate of hand-held cellular phone use by motor-vehicle drivers on a statewide level in Michigan. This study presents the results of 13 statewide surveys of cellular phone use over a 4-year period. Hand-held cellular phone use data were collected through direct observation while vehicles were stopped at intersections and freeway exit ramps. Data were weighted to be representative of all drivers traveling during daylight hours in Michigan. The study found that driver hand-held cellular phone use has more than doubled between 2001 and 2005, from 2.7% to 5.8%. This change represents an average increase of 0.78 percentage points per year. The 5.8% use rate observed in 2005 means that at any given daylight hour, around 36,550 drivers were conversing on cellular phones while driving on Michigan roadways. The trend line fitted to these data predicts that by the year 2010, driver hand-held cellular phone use will be around 8.6%, or 55,000 drivers at any given daylight hour. These results make it clear that cellular phone use while driving will continue to be an important traffic safety issue, and highlight the importance of continued attempts to generate new ways of alleviating this potential hazard.

75 FR 27504 - Substantial Product Hazard List: Hand-Held Hair Dryers

Science.gov (United States)

2010-05-17

... immersion during their use. Section 15(a) of the CPSA defines ``substantial product hazard'' to include, a....'' Hand-held hair dryers routinely contain open-coil heating elements that are, in essence, uninsulated..., bathtub, or lavatory). The proposed rule would define ``hand-held hair dryer'' as ``an electrical...

Seismo-Ionospheric Coupling as Intensified EIA Observed by Satellite Electron Density and GPS-TEC Data

Science.gov (United States)

Ryu, K.; Jangsoo, C.; Kim, S. G.; Jeong, K. S.; Parrot, M.; Pulinets, S. A.; Oyama, K. I.

2014-12-01

Examples of intensified EIA features temporally and spatially related to large earthquakes observed by satellites and GPS-TEC are introduced. The precursory, concurrent, and ex-post enhancements of EIA represented by the equatorial electron density, which are thought to be related to the M8.7 Northern Sumatra earthquake of March 2005, the M8.0 Pisco earthquake of August 2007, and the M7.9 Wenchuan Earthquake of 12 May 2008, are shown with space weather condition. Based on the case studies, statistical analysis on the ionospheric electron density data measured by the Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions satellite (DEMETER) over a period of 2005-2010 was executed in order to investigate the correlation between seismic activity and equatorial plasma density variations. To simplify the analysis, three equatorial regions with frequent earthquakes were selected and then one-dimensional time series analysis between the daily seismic activity indices and the EIA intensity indices were performed for each region with excluding the possible effects from the geomagnetic and solar activity. The statistically significant values of the lagged cross-correlation function, particularly in the region with minimal effects of longitudinal asymmetry, indicate that some of the very large earthquakes with M > 7.0 in the low latitude region can accompany observable seismo-ionospheric coupling phenomena in the form of EIA enhancements, even though the seismic activity is not the most significant driver of the equatorial ionospheric evolution. The physical mechanisms of the seismo-ionospheric coupling to explain the observation and the possibility of earthquake prediction using the EIA intensity variation are discussed.

Evaluating GPS biologging technology for studying spatial ecology of large constricting snakes

Science.gov (United States)

Smith, Brian; Hart, Kristen M.; Mazzotti, Frank J.; Basille, Mathieu; Romagosa, Christina M.

2018-01-01

Background: GPS telemetry has revolutionized the study of animal spatial ecology in the last two decades. Until recently, it has mainly been deployed on large mammals and birds, but the technology is rapidly becoming miniaturized, and applications in diverse taxa are becoming possible. Large constricting snakes are top predators in their ecosystems, and accordingly they are often a management priority, whether their populations are threatened or invasive. Fine-scale GPS tracking datasets could greatly improve our ability to understand and manage these snakes, but the ability of this new technology to deliver high-quality data in this system is unproven. In order to evaluate GPS technology in large constrictors, we GPS-tagged 13 Burmese pythons (Python bivittatus) in Everglades National Park and deployed an additional 7 GPS tags on stationary platforms to evaluate habitat-driven biases in GPS locations. Both python and test platform GPS tags were programmed to attempt a GPS fix every 90 min.Results: While overall fix rates for the tagged pythons were low (18.1%), we were still able to obtain an average of 14.5 locations/animal/week, a large improvement over once-weekly VHF tracking. We found overall accuracy and precision to be very good (mean accuracy = 7.3 m, mean precision = 12.9 m), but a very few imprecise locations were still recorded (0.2% of locations with precision > 1.0 km). We found that dense vegetation did decrease fix rate, but we concluded that the low observed fix rate was also due to python microhabitat selection underground or underwater. Half of our recovered pythons were either missing their tag or the tag had malfunctioned, resulting in no data being recovered.Conclusions: GPS biologging technology is a promising tool for obtaining frequent, accurate, and precise locations of large constricting snakes. We recommend future studies couple GPS telemetry with frequent VHF locations in order to reduce bias and limit the impact of catastrophic

Prospective evaluation of an internet-linked handheld computer critical care knowledge access system.

Science.gov (United States)

Lapinsky, Stephen E; Wax, Randy; Showalter, Randy; Martinez-Motta, J Carlos; Hallett, David; Mehta, Sangeeta; Burry, Lisa; Stewart, Thomas E

2004-12-01

Critical care physicians may benefit from immediate access to medical reference material. We evaluated the feasibility and potential benefits of a handheld computer based knowledge access system linking a central academic intensive care unit (ICU) to multiple community-based ICUs. Four community hospital ICUs with 17 physicians participated in this prospective interventional study. Following training in the use of an internet-linked, updateable handheld computer knowledge access system, the physicians used the handheld devices in their clinical environment for a 12-month intervention period. Feasibility of the system was evaluated by tracking use of the handheld computer and by conducting surveys and focus group discussions. Before and after the intervention period, participants underwent simulated patient care scenarios designed to evaluate the information sources they accessed, as well as the speed and quality of their decision making. Participants generated admission orders during each scenario, which were scored by blinded evaluators. Ten physicians (59%) used the system regularly, predominantly for nonmedical applications (median 32.8/month, interquartile range [IQR] 28.3-126.8), with medical software accessed less often (median 9/month, IQR 3.7-13.7). Eight out of 13 physicians (62%) who completed the final scenarios chose to use the handheld computer for information access. The median time to access information on the handheld handheld computer was 19 s (IQR 15-40 s). This group exhibited a significant improvement in admission order score as compared with those who used other resources (P = 0.018). Benefits and barriers to use of this technology were identified. An updateable handheld computer system is feasible as a means of point-of-care access to medical reference material and may improve clinical decision making. However, during the study, acceptance of the system was variable. Improved training and new technology may overcome some of the barriers we

An Investigation of Game-Embedded Handheld Devices to Enhance English Learning

Science.gov (United States)

Hung, Hui-Chun; Young, Shelley Shwu-Ching

2015-01-01

This study proposed and implemented a system combining the advantages of both educational games and wireless handheld technology to promote the interactive English learning in the classroom setting. An interactive English vocabulary acquisition board game was designed with the system being implemented on handheld devices. Thirty sixth-grade…

Decisions at hand: a decision support system on handhelds.

Science.gov (United States)

Zupan, B; Porenta, A; Vidmar, G; Aoki, N; Bratko, I; Beck, J R

2001-01-01

One of the applications of clinical information systems is decision support. Although the advantages of utilizing such aids have never been theoretically disputed, they have been rarely used in practice. The factor that probably often limits the utility of clinical decision support systems is the need for computing power at the very site of decision making--at the place where the patient is interviewed, in discussion rooms, etc. The paper reports on a possible solution to this problem. A decision-support shell LogReg is presented, which runs on a handheld computer. A general schema for handheld-based decision support is also proposed, where decision models are developed on personal computers/workstations, encoded in XML and then transferred to handhelds, where the models are used within a decision support shell. A use case where LogReg has been applied to clinical outcome prediction in crush injury is presented.

Using medical knowledge sources on handheld computers--a qualitative study among junior doctors.

Science.gov (United States)

Axelson, Christian; Wårdh, Inger; Strender, Lars-Erik; Nilsson, Gunnar

2007-09-01

The emergence of mobile computing could have an impact on how junior doctors learn. To exploit this opportunity it is essential to understand their information seeking process. To explore junior doctors' experiences of using medical knowledge sources on handheld computers. Interviews with five Swedish junior doctors. A qualitative manifest content analysis of a focus group interview followed by a qualitative latent content analysis of two individual interviews. A focus group interview showed that users were satisfied with access to handheld medical knowledge sources, but there was concern about contents, reliability and device dependency. Four categories emerged from individual interviews: (1) A feeling of uncertainty about using handheld technology in medical care; (2) A sense of security that handhelds can provide; (3) A need for contents to be personalized; (4) A degree of adaptability to make the handheld a versatile information tool. A theme was established to link the four categories together, as expressed in the Conclusion section. Junior doctors' experiences of using medical knowledge sources on handheld computers shed light on the need to decrease uncertainty about clinical decisions during medical internship, and to find ways to influence the level of self-confidence in the junior doctor's process of decision-making.

Augmented Reality Simulations on Handheld Computers

Science.gov (United States)

Squire, Kurt; Klopfer, Eric

2007-01-01

Advancements in handheld computing, particularly its portability, social interactivity, context sensitivity, connectivity, and individuality, open new opportunities for immersive learning environments. This article articulates the pedagogical potential of augmented reality simulations in environmental engineering education by immersing students in…

Texting while driving: is speech-based text entry less risky than handheld text entry?

Science.gov (United States)

He, J; Chaparro, A; Nguyen, B; Burge, R J; Crandall, J; Chaparro, B; Ni, R; Cao, S

2014-11-01

Research indicates that using a cell phone to talk or text while maneuvering a vehicle impairs driving performance. However, few published studies directly compare the distracting effects of texting using a hands-free (i.e., speech-based interface) versus handheld cell phone, which is an important issue for legislation, automotive interface design and driving safety training. This study compared the effect of speech-based versus handheld text entries on simulated driving performance by asking participants to perform a car following task while controlling the duration of a secondary text-entry task. Results showed that both speech-based and handheld text entries impaired driving performance relative to the drive-only condition by causing more variation in speed and lane position. Handheld text entry also increased the brake response time and increased variation in headway distance. Text entry using a speech-based cell phone was less detrimental to driving performance than handheld text entry. Nevertheless, the speech-based text entry task still significantly impaired driving compared to the drive-only condition. These results suggest that speech-based text entry disrupts driving, but reduces the level of performance interference compared to text entry with a handheld device. In addition, the difference in the distraction effect caused by speech-based and handheld text entry is not simply due to the difference in task duration. Copyright © 2014 Elsevier Ltd. All rights reserved.

Development of Real-Time Dual-Display Handheld and Bench-Top Hybrid-Mode SD-OCTs

Directory of Open Access Journals (Sweden)

Nam Hyun Cho

2014-01-01

Full Text Available Development of a dual-display handheld optical coherence tomography (OCT system for retina and optic-nerve-head diagnosis beyond the volunteer motion constraints is reported. The developed system is portable and easily movable, containing the compact portable OCT system that includes the handheld probe and computer. Eye posterior chambers were diagnosed using the handheld probe, and the probe could be fixed to the bench-top cradle depending on the volunteers’ physical condition. The images obtained using this handheld probe were displayed in real time on the computer monitor and on a small secondary built-in monitor; the displayed images were saved using the handheld probe’s built-in button. Large-scale signal-processing procedures such as k-domain linearization, fast Fourier transform (FFT, and log-scaling signal processing can be rapidly applied using graphics-processing-unit (GPU accelerated processing rather than central-processing-unit (CPU processing. The Labview-based system resolution is 1,024 × 512 pixels, and the frame rate is 56 frames/s, useful for real-time display. The 3D images of the posterior chambers including the retina, optic-nerve head, blood vessels, and optic nerve were composed using real-time displayed images with 500 × 500 × 500 pixel resolution. A handheld and bench-top hybrid mode with a dual-display handheld OCT was developed to overcome the drawbacks of the conventional method.

A New Technique to Observe ENSO Activity via Ground-Based GPS Receivers

Science.gov (United States)

Suparta, Wayan; Iskandar, Ahmad; Singh, Mandeep Singh Jit

In an attempt to study the effects of global climate change in the tropics for improving global climate model, this paper aims to detect the ENSO events, especially El Nino phase by using ground-based GPS receivers. Precipitable water vapor (PWV) obtained from the Global Positioning System (GPS) Meteorology measurements in line with the sea surface temperature anomaly (SSTa) are used to connect their response to El Niño activity. The data gathered from four selected stations over the Southeast Asia, namely PIMO (Philippines), KUAL (Malaysia), NTUS (Singapore) and BAKO (Indonesia) for the year of 2009/2010 were processed. A strong correlation was observed for PIMO station with a correlation coefficient of -0.90, significantly at the 99 % confidence level. In general, the relationship between GPS PWV and SSTa at all stations on a weekly basis showed with a negative correlation. The negative correlation indicates that during the El Niño event, the PWV variation was in decreased trend. Decreased trend of PWV value is caused by a dry season that affected the GPS signals in the ocean-atmospheric coupling. Based on these promising results, we can propose that the ground-based GPS receiver is capable used to monitor ENSO activity and this is a new prospective method that previously unexplored.

GPS operations at Olkiluoto in 2011

International Nuclear Information System (INIS)

Koivula, H.; Kallio, U.; Nyberg, S.; Jokela, J.; Poutanen, M.

2012-06-01

The Finnish Geodetic Institute has studied crustal deformations at Olkiluoto, Kivetty and Romuvaara in co-operation with Posiva Oy since 1995. At Olkiluoto a total of 32 GPS campaigns have been carried out at inner network since 1995 and 17 campaigns at outer network since 2003. Kivetty and Romuvaara were not measured in 2011. In the Olkiluoto inner network 80 percent of the estimated change rates are smaller than 0.10 mm/a. One third of the change rates are statistically significant. They are mainly related to the Olkiluoto permanent station (GPS1) and to the pillars GPS6 and GPS13. The change rates related to GPS6 are not realistic due to the site-specific changes affecting the time series. The maximum change rate (-0.20 mm/a ± 0.05 mm/a) is related to GPS13. The time series of GPS13 is half the length of other pillars and therefore, the change rates are more uncertain. In the Olkiluoto outer network the maximum and statistically significant change rate is between GPS1-GPS11 (0.39 mm/a ± 0.06 mm/a). Pillar GPS12 was not observed this year. The change rates of baselines GPS1-GPS14 and GPS1-GPS15 are first time statistically significant. The change rates indicate a small movement of the GPS1 pillar. The baseline GPS1-GPS11 crosses an old fracture zone locating in the direction of the Eurajoensalmi, which might be a reason for the deformation. On the other hand, the Onkalo excavations in the vicinity of the Olkiluoto permanent station (GPS1) may cause some movement. Electronic distance measurements have been performed at Olkiluoto at the baseline GPS7-GPS8 using the Mekometer since 2002. The measurements have been carried out simultaneously with GPS campaigns. Based on 19 measurements in 10 years, the trends of the two time series seems to be similar. Due to unmodelled or dismodelled geometrical offsets and the scale difference between GPS measurements and EDM there is about 0.3 mm difference between distances GPS7-GPS8 derived from GPS measurements and EDM. It is

GPS operations at Olkiluoto in 2011

Energy Technology Data Exchange (ETDEWEB)

Koivula, H.; Kallio, U.; Nyberg, S.; Jokela, J.; Poutanen, M. [Finnish Geodetic Institute, Masala (Finland)

2012-06-15

The Finnish Geodetic Institute has studied crustal deformations at Olkiluoto, Kivetty and Romuvaara in co-operation with Posiva Oy since 1995. At Olkiluoto a total of 32 GPS campaigns have been carried out at inner network since 1995 and 17 campaigns at outer network since 2003. Kivetty and Romuvaara were not measured in 2011. In the Olkiluoto inner network 80 percent of the estimated change rates are smaller than 0.10 mm/a. One third of the change rates are statistically significant. They are mainly related to the Olkiluoto permanent station (GPS1) and to the pillars GPS6 and GPS13. The change rates related to GPS6 are not realistic due to the site-specific changes affecting the time series. The maximum change rate (-0.20 mm/a {+-} 0.05 mm/a) is related to GPS13. The time series of GPS13 is half the length of other pillars and therefore, the change rates are more uncertain. In the Olkiluoto outer network the maximum and statistically significant change rate is between GPS1-GPS11 (0.39 mm/a {+-} 0.06 mm/a). Pillar GPS12 was not observed this year. The change rates of baselines GPS1-GPS14 and GPS1-GPS15 are first time statistically significant. The change rates indicate a small movement of the GPS1 pillar. The baseline GPS1-GPS11 crosses an old fracture zone locating in the direction of the Eurajoensalmi, which might be a reason for the deformation. On the other hand, the Onkalo excavations in the vicinity of the Olkiluoto permanent station (GPS1) may cause some movement. Electronic distance measurements have been performed at Olkiluoto at the baseline GPS7-GPS8 using the Mekometer since 2002. The measurements have been carried out simultaneously with GPS campaigns. Based on 19 measurements in 10 years, the trends of the two time series seems to be similar. Due to unmodelled or dismodelled geometrical offsets and the scale difference between GPS measurements and EDM there is about 0.3 mm difference between distances GPS7-GPS8 derived from GPS measurements and EDM

Improving car passengers' comfort and experience by supporting the use of handheld devices.

Science.gov (United States)

van Veen, S A T; Hiemstra-van Mastrigt, S; Kamp, I; Vink, P

2014-01-01

There is a demand for interiors to support other activities in a car than controlling the vehicle. Currently, this is the case for the car passengers and--in the future--autonomous driving cars will also facilitate drivers to perform other activities. One of these activities is working with handheld devices. Previous research shows that people experience problems when using handheld devices in a moving vehicle and the use of handheld devices generally causes unwanted neck flexion [Young et al. 2012; Sin and Zu 2011; Gold et al.2011]. In this study, armrests are designed to support the arms when using handheld devices in a driving car in order to decrease neck flexion. Neck flexion was measured by attaching markers on the C7 and tragus. Discomfort was indicated on a body map on a scale 1-10. User experience was evaluated in a semi-structured interview. Neck flexion is significantly decreased by the support of the armrests and approaches a neutral position. Furthermore, overall comfort and comfort in the neck region specifically are significantly increased. Subjects appreciate the body posture facilitated by the armrests and 9 out of 10 prefer using handheld devices with the armrests compared to using handheld devices without the armrests. More efforts are needed to develop the mock-up into an established product, but the angles and dimensions presented in this study could serve as guidelines.

Ultrasonography with a hand-held device for the diagnosis of acute appendicitis

International Nuclear Information System (INIS)

Kameda, Toru; Takahashi, Isao

2009-01-01

The purpose of this study was to evaluate the accuracy of ultrasonography (US) with a hand-held device for the diagnosis of acute appendicitis in the emergency room. US with a hand-held device was performed by the first author in 33 patients suspected of having appendicitis in the emergency room. From these 33 patients, 24 who subsequently underwent computed tomography (CT) or surgery were included in this study. The accuracy of US with the hand-held device for the diagnosis of acute appendicitis was evaluated based on the findings of CT or surgery. CT and surgery were performed in 22 and 12 patients, respectively. Final diagnoses were acute appendicitis (n=18), terminal ileitis (n=2), pelvic inflammatory disease (n=2), diverticulitis (n=1), and ureterolithiasis (n=1). The US yielded a sensitivity of 78% and a positive predictive value of 100%. The shortest distance between the abdominal wall and the appendix measured on CT was less than 40 mm in 11 patients. In ten (91%) of the 11 patients US with the hand-held device showed the swollen appendix. US with a hand-held device is potentially useful in the positive identification of acute appendicitis, but further investigation is needed to prove its utility in the routine diagnosis of acute appendicitis. (author)

GPS measurements and finite element modeling of the earthquake cycle along the Middle America subduction zone

Science.gov (United States)

Correa Mora, Francisco

We model surface deformation recorded by GPS stations along the Pacific coasts of Mexico and Central America to estimate the magnitude of and variations in frictional locking (coupling) along the subduction interface, toward a better understanding of seismic hazard in these earthquake-prone regions. The first chapter describes my primary analysis technique, namely 3-dimensional finite element modeling to simulate subduction and bounded-variable inversions that optimize the fit to the GPS velocity field. This chapter focuses on and describes interseismic coupling of the Oaxaca segment of the Mexican subduction zone and introduces an analysis of transient slip events that occur in this region. Our results indicate that coupling is strong within the rupture zone of the 1978 Ms=7.8 Oaxaca earthquake, making this region a potential source of a future large earthquake. However, we also find evidence for significant variations in coupling on the subduction interface over distances of only tens of kilometers, decreasing toward the outer edges of the 1978 rupture zone. In the second chapter, we study in more detail some of the slow slip events that have been recorded over a broad area of southern Mexico, with emphasis on their space-time behavior. Our modeling indicates that transient deformation beneath southern Mexico is focused in two distinct slip patches mostly located downdip from seismogenic areas beneath Guerrero and Oaxaca. Contrary to conclusions reached in one previous study, we find no evidence for a spatial or temporal correlation between transient slip that occurs in these two widely separated source regions. Finally, chapter three extends the modeling techniques to new GPS data in Central America, where subduction coupling is weak or zero and the upper plate deformation is much more complex than in Mexico. Cocos-Caribbean plate convergence beneath El Salvador and Nicaragua is accompanied by subduction and trench-parallel motion of the forearc. Our GPS

Using GPS Imaging to Unravel Vertical Land Motions in the Interior Pacific Northwest

Science.gov (United States)

Overacker, J.; Hammond, W. C.; Kraner, M.; Blewitt, G.

2017-12-01

GPS Imaging uses robust trends in time series of GPS positions to create a velocity field that can reveal rates and patterns of vertical motions that would be otherwise difficult to detect. We have constructed an image of vertical land velocities within the interior Pacific Northwest region of the United States using GPS Imaging. The image shows a 50-250 km wide swath of approximately 2 mm/yr of subsidence seemingly unrelated to topographic features of the region. The extent of the signal roughly corresponds to the Juan de Fuca plate subduction latitudes and longitude of the Cascade arc. This suggests that the signal could be associated with ongoing crustal deformation possibly related to plate-scale geodynamic forces arising from interseismic coupling, long term plate boundary tractions, volcanic loading, and/or mantle flow. However, hydrological loading from accumulating precipitation in the Cascades and in the region's groundwater basins, and possible effects from Glacial Isostatic Adjustment (GIA) near its hinge line cannot be discounted as potential contributors to the observed subsidence signal. Here we attempt to unravel the contributions of hydrological loading and GIA to the vertical GPS signal observed within the interior Pacific Northwest. In order to determine the non-tectonic contributions to the observed vertical GPS Image, we will examine how the subsidence rate changes over time using early and late period comparisons. GPS, GRACE, and climatic data will be used in conjunction to disentangle the hydrological effect from the GPS Image. GIA models of the Western Cordillera will be compared with the patterns in the GPS Image to assess whether the signal can be explained with current models of GIA. Our presentation will document the signals, uncertainties, and hypotheses for the possible mechanisms behind this subsidence and attempt to quantify their relation and contribution to the observed deformation signal. Figure 1: Pacific Northwest GPS Imaging

Introducing handheld computing into a residency program: preliminary results from qualitative and quantitative inquiry.

OpenAIRE

Manning, B.; Gadd, C. S.

2001-01-01

Although published reports describe specific handheld computer applications in medical training, we know very little yet about how, and how well, handheld computing fits into the spectrum of information resources available for patient care and physician training. This paper reports preliminary quantitative and qualitative results from an evaluation study designed to track changes in computer usage patterns and computer-related attitudes before and after introduction of handheld computing. Pre...

Inertial and GPS data integration for positioning and tracking of GPR

Science.gov (United States)

Chicarella, Simone; D'Alvano, Alessandro; Ferrara, Vincenzo; Frezza, Fabrizio; Pajewski, Lara

2015-04-01

approach to data processing and visualization,' Proceedings of 15th IEEE International Conference on Ground Penetrating Radar - GPR 2014, Brussels, Belgium, June 30 - July 4, 2014, pp. 913-918. [2] S. Urbini, L. Vittuari, and S. Gandolfi, 'GPR and GPS data integration: examples of application in Antarctica,' Annali di Geofisica, Vol. 44, No. 4, August 2001, pp. 687-702. [3] V. Prokhorenko, V. Ivashchuk, S. Korsun, and O. Dykovska, 'An Inertial Measurement Unit Application for a GPR Tracking and Positioning,' Proceedings of the 12th International Conference on Ground Penetrating Radar, June 15-19, 2008, Birmingham, UK, pp. 19-24. [4] M. Pasternak, W. Miluski, W. Czarnecki, and J. Pietrasinski, 'An optoelectronic-inertial system for handheld GPR positioning,' Proceedings of the 15th IEEE International Radar Symposium (IRS), Gdansk, Poland, June 16-18, 2014, pp. 1-4. [5] L. Crocco and V. Ferrara, 'A Review on Ground Penetrating Radar Technology for the Detection of Buried or Trapped Victims,' Proceedings of the IEEE 2nd International Workshop on Collaborations in Emergency Response and Disaster Management (ERDM 2014) as part of 2014 International Conference on Collaboration Technologies and Systems (CTS 2014) - Minneapolis (Minnesota, USA), May 19-23, 2014, pp. 535-540.

GPS phase scintillation at high latitudes during the geomagnetic storm of 17-18 March 2015

DEFF Research Database (Denmark)

Prikryl, P.; Ghoddousi-Fard, R.; Weygand, J. M.

2016-01-01

The geomagnetic storm of 17–18 March 2015 was caused by the impacts of a coronal mass ejection and a high-speed plasma stream from a coronal hole. The high-latitude ionosphere dynamics is studied using arrays of ground-based instruments including GPS receivers, HF radars, ionosondes, riometers......, and magnetometers. The phase scintillation index is computed for signals sampled at a rate of up to 100 Hz by specialized GPS scintillation receivers supplemented by the phase scintillation proxy index obtained from geodetic-quality GPS data sampled at 1 Hz. In the context of solar wind coupling...... to the magnetosphere-ionosphere system, it is shown that GPS phase scintillation is primarily enhanced in the cusp, the tongue of ionization that is broken into patches drawn into the polar cap from the dayside storm-enhanced plasma density, and in the auroral oval. In this paper we examine the relation between...

Indoor Positioning Using GPS Revisited

DEFF Research Database (Denmark)

Kjærgaard, Mikkel Baun; Blunck, Henrik; Godsk, Torben

2010-01-01

It has been considered a fact that GPS performs too poorly inside buildings to provide usable indoor positioning. We analyze results of a measurement campaign to improve on the understanding of indoor GPS reception characteristics. The results show that using state-of-the-art receivers GPS...... low signal-to-noise ratios, multipath phenomena or bad satellite constellation geometry. We have also measured the indoor performance of embedded GPS receivers in mobile phones which provided lower availability and accuracy than state-of-the-art ones. Finally, we consider how the GPS performance...

40 CFR 90.129 - Fuel tank permeation from handheld engines and equipment.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Fuel tank permeation from handheld... KILOWATTS Emission Standards and Certification Provisions § 90.129 Fuel tank permeation from handheld... equipment with respect to fuel tanks. For the purposes of this section, fuel tanks do not include fuel caps...

TLALOCNet continuous GPS-Met Array in Mexico supporting the 2017 NAM GPS Hydrometeorological Network.

Science.gov (United States)

Cabral-Cano, E.; Salazar-Tlaczani, L.; Adams, D. K.; Vivoni, E. R.; Grutter, M.; Serra, Y. L.; DeMets, C.; Galetzka, J.; Feaux, K.; Mattioli, G. S.; Miller, M. M.

2017-12-01

TLALOCNet is a network of continuous GPS and meteorology stations in Mexico to study atmospheric and solid earth processes. This recently completed network spans most of Mexico with a strong coverage emphasis on southern and western Mexico. This network, funded by NSF, CONACyT and UNAM, recently built 40 cGPS-Met sites to EarthScope Plate Boundary Observatory standards and upgraded 25 additional GPS stations. TLALOCNet provides open and freely available raw GPS data, and high frequency surface meteorology measurements, and time series of daily positions. This is accomplished through the development of the TLALOCNet data center (http://tlalocnet.udg.mx) that serves as a collection and distribution point. This data center is based on UNAVCO's Dataworks-GSAC software and also works as part of UNAVCO's seamless archive for discovery, sharing, and access to GPS data. The TLALOCNet data center also contains contributed data from several regional GPS networks in Mexico for a total of 100+ stations. By using the same protocols and structure as the UNAVCO and other COCONet regional data centers, the scientific community has the capability of accessing data from the largest Mexican GPS network. This archive provides a fully queryable and scriptable GPS and Meteorological data retrieval point. In addition, real-time 1Hz streams from selected TLALOCNet stations are available in BINEX, RTCM 2.3 and RTCM 3.1 formats via the Networked Transport of RTCM via Internet Protocol (NTRIP) for real-time seismic and weather forecasting applications. TLALOCNet served as a GPS-Met backbone for the binational Mexico-US North American Monsoon GPS Hydrometeorological Network 2017 campaign experiment. This innovative experiment attempts to address water vapor source regions and land-surface water vapor flux contributions to precipitation (i.e., moisture recycling) during the 2017 North American Monsoon in Baja California, Sonora, Chihuahua, and Arizona. Models suggest that moisture recycling is

Fusing Open Source Intelligence and Handheld Situational Awareness - Benghazi Case Study

Science.gov (United States)

2014-10-01

1 DM-0001694 Fusing Open Source Intelligence and Handheld Situational Awareness Benghazi Case Study Jeff Boleng, PhD Marc Novakouski Gene...command and control element at the CIA compound that would have been monitoring OSINT and other sources of intelligence before the attack and... Source Intelligence and Handheld Situational Awareness - Benghazi Case Study 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

Tightly-coupled real-time analysis of GPS and accelerometer data for translational and rotational ground motions and application to earthquake and tsunami early warning

Science.gov (United States)

Geng, J.; Bock, Y.; Melgar, D.; Hasse, J.; Crowell, B. W.

2013-12-01

High-rate GPS can play an important role in earthquake early warning (EEW) systems for large (>M6) events by providing permanent displacements immediately as they are achieved, to be used in source inversions that can be repeatedly updated as more information becomes available. This is most valuable to implement at a site very near the potential source rupture, where broadband seismometers are likely to clip, and accelerometer data cannot be objectively integrated to produce reliable displacements in real time. At present, more than 525 real-time GPS stations have been established in western North America, which are being integrated into EEW systems. Our analysis technique relies on a tightly-coupled combination of GPS and accelerometer data, an extension of precise point positioning with ambiguity resolution (PPP-AR). We operate a PPP service based on North American stations available through the IGS and UNAVCO/PBO. The service provides real-time satellite clock and fractional-cycle bias products that allow us to position individual client stations in the zone of deformation. The service reference stations are chosen to be further than 200 km from the primary zones of tectonic deformation in the western U.S. to avoid contamination of the satellite products during a large seismic event. At client stations, accelerometer data are applied as tight constraints on the positions between epochs in PPP-AR, which improves cycle-slip repair and rapid ambiguity resolution after GPS outages. Furthermore, we estimate site displacements, seismic velocities, and coseismic ground tilts to facilitate the analysis of ground motion characteristics and the inversion for source mechanisms. The seismogeodetic displacement and velocity waveforms preserves the detection of P wave arrivals, and provides P-wave arrival displacement that is key new information for EEW. Our innovative solution method for coseismic tilts mitigates an error source that has continually plagued strong motion

Handheld computers in nursing education: PDA pilot project.

Science.gov (United States)

Koeniger-Donohue, Rebecca

2008-02-01

Interest in the use and application of handheld technology at undergraduate and graduate nursing programs across the country is growing rapidly. Personal digital assistants (PDAs) are often referred to as a "peripheral brain" because they can save time, decrease errors, and simplify information retrieval at the point of care. In addition, research results support the notion that PDAs enhance nursing clinical education and are an effective student learning resource. However, most nursing programs lack the full range of technological resources to implement and provide ongoing support for handheld technology use by faculty and students. This article describes a 9-month pilot project for the initial use of PDAs by novice faculty and students at Simmons College.

GPS: Public Utility or Software Platform

Science.gov (United States)

2016-09-01

train for GPS loss, encourage use of GPS signal integrity monitors , develop in- vehicle GPS backups, and evaluate the range of radio...literature prevent the full quantification of exactly how vulnerable GPS is to service interruption. This thesis used constant comparison analysis to...criticality, resilience, and vulnerability. This methodology overcomes research limitations by using GPS system design, operations, and policies as

Handheld ESPI-speckle interferometer

DEFF Research Database (Denmark)

Skov Hansen, René

2003-01-01

. The interferometer presented here is a compact version of the set-up, Which is capable of measuring displacements of small objects, having either a specularly reflecting-or a diffusely scattering surface. The small optical set-up together with the use of the popular USB-communication for acquiring the images...... and controlling the phase of the reference wave constitutes a compact "handheld" instrument and eliminates the need for installing extra hardware, such as frame grabber and Digital to Analog converter, in the host computer....

Tightly Coupled Integration of GPS Ambiguity Fixed Precise Point Positioning and MEMS-INS through a Troposphere-Constrained Adaptive Kalman Filter

Directory of Open Access Journals (Sweden)

Houzeng Han

2016-07-01

Full Text Available Precise Point Positioning (PPP makes use of the undifferenced pseudorange and carrier phase measurements with ionospheric-free (IF combinations to achieve centimeter-level positioning accuracy. Conventionally, the IF ambiguities are estimated as float values. To improve the PPP positioning accuracy and shorten the convergence time, the integer phase clock model with between-satellites single-difference (BSSD operation is used to recover the integer property. However, the continuity and availability of stand-alone PPP is largely restricted by the observation environment. The positioning performance will be significantly degraded when GPS operates under challenging environments, if less than five satellites are present. A commonly used approach is integrating a low cost inertial sensor to improve the positioning performance and robustness. In this study, a tightly coupled (TC algorithm is implemented by integrating PPP with inertial navigation system (INS using an Extended Kalman filter (EKF. The navigation states, inertial sensor errors and GPS error states are estimated together. The troposphere constrained approach, which utilizes external tropospheric delay as virtual observation, is applied to further improve the ambiguity-fixed height positioning accuracy, and an improved adaptive filtering strategy is implemented to improve the covariance modelling considering the realistic noise effect. A field vehicular test with a geodetic GPS receiver and a low cost inertial sensor was conducted to validate the improvement on positioning performance with the proposed approach. The results show that the positioning accuracy has been improved with inertial aiding. Centimeter-level positioning accuracy is achievable during the test, and the PPP/INS TC integration achieves a fast re-convergence after signal outages. For troposphere constrained solutions, a significant improvement for the height component has been obtained. The overall positioning accuracies

Handheld Multi-Gas Meters Market Survey Report

Energy Technology Data Exchange (ETDEWEB)

Williams, Gustavious [Brigham Young Univ., Provo, UT (United States); Wald-Hopkins, Mark David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Obrey, Stephen J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Akhadov, Valida Dushdurova [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-06-23

Handheld multi-gas meters (MGMs) are equipped with sensors to monitor oxygen (O2) levels and additional sensors to detect the presence of combustible or toxic gases in the environment. This report is limited to operational response-type MGMs that include at least four different sensors. These sensors can vary by type and by the chemical monitored. In real time, the sensors report the concentration of monitored gases in the atmosphere near the MGM. To provide emergency responders with information on handheld multi-gas meters, the System Assessment and Validation for Emergency Responders (SAVER) Program conducted a market survey. This market survey report is based on information gathered between November 2015 and February 2016 from vendors, Internet research, industry publications, an emergency responder focus group, and a government issued Request for Information (RFI) that was posted on the Federal Business Opportunities website.

GPS/INS Sensor Fusion Using GPS Wind up Model

Science.gov (United States)

Williamson, Walton R. (Inventor)

2013-01-01

A method of stabilizing an inertial navigation system (INS), includes the steps of: receiving data from an inertial navigation system; and receiving a finite number of carrier phase observables using at least one GPS receiver from a plurality of GPS satellites; calculating a phase wind up correction; correcting at least one of the finite number of carrier phase observables using the phase wind up correction; and calculating a corrected IMU attitude or velocity or position using the corrected at least one of the finite number of carrier phase observables; and performing a step selected from the steps consisting of recording, reporting, or providing the corrected IMU attitude or velocity or position to another process that uses the corrected IMU attitude or velocity or position. A GPS stabilized inertial navigation system apparatus is also described.

Efficient GPS Position Determination Algorithms

National Research Council Canada - National Science Library

Nguyen, Thao Q

2007-01-01

... differential GPS algorithm for a network of users. The stand-alone user GPS algorithm is a direct, closed-form, and efficient new position determination algorithm that exploits the closed-form solution of the GPS trilateration equations and works...

Who’s That Girl? Handheld Augmented Reality for Printed Photo Books

OpenAIRE

Henze , Niels; Boll , Susanne

2011-01-01

Part 1: Long and Short Papers; International audience; Augmented reality on mobile phones has recently made major progress. Lightweight, markerless object recognition and tracking makes handheld Augmented Reality feasible for new application domains. As this field is technology driven the interface design has mostly been neglected. In this paper we investigate visualization techniques for augmenting printed documents using handheld Augmented Reality. We selected the augmentation of printed ph...

Energy Cost of Active and Sedentary Music Video Games: Drum and Handheld Gaming vs. Walking and Sitting.

Science.gov (United States)

Miranda, Edwin; Overstreet, Brittany S; Fountain, William A; Gutierrez, Vincent; Kolankowski, Michael; Overstreet, Matthew L; Sapp, Ryan M; Wolff, Christopher A; Mazzetti, Scott A

2017-01-01

To compare energy expenditure during and after active and handheld video game drumming compared to walking and sitting. Ten experienced, college-aged men performed four protocols (one per week): no-exercise seated control (CTRL), virtual drumming on a handheld gaming device (HANDHELD), active drumming on drum pads (DRUM), and walking on a treadmill at ~30% of VO 2max (WALK). Protocols were performed after an overnight fast, and expired air was collected continuously during (30min) and after (30min) exercise. DRUM and HANDHELD song lists, day of the week, and time of day were identical for each participant. Significant differences (p DRUM > HANDHELD. No significant differences in the rates of energy expenditure among groups during recovery were observed. Total energy expenditure was significantly greater (p < 0.05) during WALK (149.5 ± 30.6 kcal) compared to DRUM (118.7 ± 18.8 kcal) and HANDHELD (44.9±11.6 kcal), and greater during DRUM compared to HANDHELD. Total energy expenditure was not significantly different between HANDHELD (44.9 ± 11.6 kcal) and CTRL (38.2 ± 6.0 kcal). Active video game drumming at expert-level significantly increased energy expenditure compared to handheld, but it hardly met moderate-intensity activity standards, and energy expenditure was greatest during walking. Energy expenditure with handheld video game drumming was not different from no-exercise control. Thus, traditional aerobic exercise remains at the forefront for achieving the minimum amount and intensity of physical activity for health, individuals desiring to use video games for achieving weekly physical activity recommendations should choose games that require significant involvement of lower-body musculature, and time spent playing sedentary games should be a limited part of an active lifestyle.

Active case finding strategy for chronic obstructive pulmonary disease with handheld spirometry.

Science.gov (United States)

Kim, Joo Kyung; Lee, Chang Min; Park, Ji Young; Kim, Joo Hee; Park, Sung-Hoon; Jang, Seung Hun; Jung, Ki-Suck; Yoo, Kwang Ha; Park, Yong Bum; Rhee, Chin Kook; Kim, Deog Kyeom; Hwang, Yong Il

2016-12-01

The early detection and diagnosis of chronic obstructive pulmonary disease (COPD) is critical to providing appropriate and timely treatment. We explored a new active case-finding strategy for COPD using handheld spirometry.We recruited subjects over 40 years of age with a smoking history of more than 10 pack-years who visited a primary clinic complaining of respiratory symptoms. A total of 190 of subjects were enrolled. Medical information was obtained from historical records and physical examination by general practitioners. All subjects had their pulmonary function evaluated using handheld spirometry with a COPD-6 device. Because forced expiratory volume in 6 seconds (FEV6) has been suggested as an alternative to FVC, we measured forced expiratory volume in 1 second (FEV1)/FEV6 for diagnosis of airflow limitation. All subjects were then referred to tertiary referral hospitals to complete a "Could it be COPD?" questionnaire, handheld spiromtery, and conventional spirometry. The results of each instrument were compared to evaluate the efficacy of both handheld spirometry and the questionnaire.COPD was newly diagnosed in 45 (23.7%) patients. According to our receiver-operating characteristic (ROC) curve analysis, sensitivity and specificity were maximal when the FEV1/FEV6 ratio was less than 77%. The area under the ROC curve was 0.759. The sensitivity, specificity, positive predictive value, and negative predictive value were 72.7%, 77.1%, 50%, and 90%, respectively. The area under the ROC curve of respiratory symptoms listed on the questionnaire ranged from 0.5 to 0.65, which indicates that there is almost no difference compared with the results of handheld spirometry.The present study demonstrated the efficacy of handheld spirometry as an active case-finding tool for COPD in a primary clinical setting. This study suggested that physicians should recommend handheld spirometry for people over the age of 40, who have a smoking history of more than 10 pack

Handheld single photon emission computed tomography (handheld SPECT) navigated video-assisted thoracoscopic surgery of computer tomography-guided radioactively marked pulmonary lesions.

Science.gov (United States)

Müller, Joachim; Putora, Paul Martin; Schneider, Tino; Zeisel, Christoph; Brutsche, Martin; Baty, Florent; Markus, Alexander; Kick, Jochen

2016-09-01

Radioactive marking can be a valuable extension to minimally invasive surgery. The technique has been clinically applied in procedures involving sentinel lymph nodes, parathyroidectomy as well as interventions in thoracic surgery. Improvements in equipment and techniques allow one to improve the limits. Pulmonary nodules are frequently surgically removed for diagnostic or therapeutic reasons; here video-assisted thoracoscopic surgery (VATS) is the preferred technique. VATS might be impossible with nodules that are small or located deep in the lung. In this study, we examined the clinical application and safety of employing the newly developed handheld single photon emission tomography (handheld SPECT) device in combination with CT-guided radioactive marking of pulmonary nodules. In this pilot study, 10 subjects requiring surgical resection of a pulmonary nodule were included. The technique involved CT-guided marking of the target nodule with a 20-G needle, with subsequent injection of 25-30 MBq (effective: 7-14 MBq) Tc-99m MAA (Macro Albumin Aggregate). Quality control was made with conventional SPECT-CT to confirm the correct localization and exclude possible complications related to the puncture procedure. VATS was subsequently carried out using the handheld SPECT to localize the radioactivity intraoperatively and therefore the target nodule. A 3D virtual image was superimposed on the intraoperative visual image for surgical guidance. In 9 of the 10 subjects, the radioactive application was successfully placed directly in or in the immediate vicinity of the target nodule. The average size of the involved nodules was 9 mm (range 4-15). All successfully marked nodules were subsequently completely excised (R0) using VATS. The procedure was well tolerated. An asymptomatic clinically insignificant pneumothorax occurred in 5 subjects. Two subjects were found to have non-significant discrete haemorrhage in the infiltration canal of the needle. In a single subject, the

Standardization of GPS data processing

International Nuclear Information System (INIS)

Park, Pil Ho

2001-06-01

A nationwide GPS network has been constructed with about 60 permanent GPS stations after late 1990s in Korea. For using the GPS in variety of application area like crustal deformation, positioning, or monitoring upper atmosphere, it is necessary to have ability to process the data precisely. Now Korea Astronomy Observatory has the precise GPS data processing technique in Korea because it is difficult to understand characteristics of the parameters we want to estimate, resolve the integer ambiguity, and analyze many errors. There are three reliable GPS data processing software in the world ; Bernese(University of Berne), GIPSY-OASIS(JPL), GAMIT(MIT). These software allow us to achieve millimeter accuracy in the horizontal position and about 1 cm accuracy vertically even for regional networks with a diameter of several thousand kilometers. But we established the standard of GPS data processing using Bernese as main tool and GIPSY O ASIS as side

GPS Position Time Series @ JPL

Science.gov (United States)

Owen, Susan; Moore, Angelyn; Kedar, Sharon; Liu, Zhen; Webb, Frank; Heflin, Mike; Desai, Shailen

2013-01-01

Different flavors of GPS time series analysis at JPL - Use same GPS Precise Point Positioning Analysis raw time series - Variations in time series analysis/post-processing driven by different users. center dot JPL Global Time Series/Velocities - researchers studying reference frame, combining with VLBI/SLR/DORIS center dot JPL/SOPAC Combined Time Series/Velocities - crustal deformation for tectonic, volcanic, ground water studies center dot ARIA Time Series/Coseismic Data Products - Hazard monitoring and response focused center dot ARIA data system designed to integrate GPS and InSAR - GPS tropospheric delay used for correcting InSAR - Caltech's GIANT time series analysis uses GPS to correct orbital errors in InSAR - Zhen Liu's talking tomorrow on InSAR Time Series analysis

Semantic Enrichment of GPS Trajectories

NARCIS (Netherlands)

de Graaff, V.; van Keulen, Maurice; de By, R.A.

2012-01-01

Semantic annotation of GPS trajectories helps us to recognize the interests of the creator of the GPS trajectories. Automating this trajectory annotation circumvents the requirement of additional user input. To annotate the GPS traces automatically, two types of automated input are required: 1) a

An Introduction to the Tibet cGPS pilot project: TigiCAS

Science.gov (United States)

Zhang, Z.; Liu, J.; Galetzka, J.; Avouac, J.; Tapponnier, P.; Zeng, L.; Gan, W.; Shen, Z.; Wang, M.

2007-12-01

The convergence between India and Eurasia is the¡¡prototype of continental collision in action. Compared¡¡to geological history and fault kinematics studies, the present-day, regional pattern of strain-partitioning¡¡is still inadequately known. Among limited geodetic¡¡efforts in the past decade or two, most have been focused¡¡on refining measurements of the current crustal¡¡shortening rate across the Himalaya. The vast region¡¡immediately to the north is sparsely instrumented, with only one continuous GPS station (Lhasa) within¡¡the plateau proper. Campaign stations are few and¡¡ill-positioned, mostly along major roads, providing¡¡poor constraints on present-day slip-rates on individual¡¡active faults. The extant GPS network configuration is thus still insufficient to discriminate between block vs continuum deformation. In November 2006, the¡¡Chinese Academy of Sciences led a pilot program and¡¡installed 6 continuous GPS stations in southern Tibet, crossing the NS-trending normal fault systems and¡¡complementing the Nepal cGPS profiles. We present¡¡here the new sites, preliminary data processing results, and the spatial relationship with ongoing or planned¡¡continuous GPS sites from a couple of other projects. Together with such projects, TigiCAS will provide¡¡a substantial increase in geodetic data in the¡¡Himalayan-Tibet convergent belt in the next few¡¡years, and lead to a better understanding of¡¡contemporary deformation of the region.

Performance Enhancement of Land Vehicle Positioning Using Multiple GPS Receivers in an Urban Area

Directory of Open Access Journals (Sweden)

Jong-Hwa Song

2016-10-01

Full Text Available The Global Positioning System (GPS is the most widely used navigation system in land vehicle applications. In urban areas, the GPS suffers from insufficient signal strength, multipath propagation and non-line-of-sight (NLOS errors, so it thus becomes difficult to obtain accurate and reliable position information. In this paper, an integration algorithm for multiple receivers is proposed to enhance the positioning performance of GPS for land vehicles in urban areas. The pseudoranges of multiple receivers are integrated based on a tightly coupled approach, and erroneous measurements are detected by testing the closeness of the pseudoranges. In order to fairly compare the pseudoranges, GPS errors and terms arising due to the differences between the positions of the receivers need to be compensated. The double-difference technique is used to eliminate GPS errors in the pseudoranges, and the geometrical distance is corrected by projecting the baseline vector between pairs of receivers. In order to test and analyze the proposed algorithm, an experiment involving live data was performed. The positioning performance of the algorithm was compared with that of the receiver autonomous integrity monitoring (RAIM-based integration algorithm for multiple receivers. The test results showed that the proposed algorithm yields more accurate position information in urban areas.

Position statement on use of hand-held portable dental X-ray equipment

International Nuclear Information System (INIS)

2014-06-01

The position statement focuses on justification in the medical field, in particular on the use of hand-held portable dental x-ray equipment. It supplements another HERCA position paper, providing a general overview of the use of all hand-held portable X-ray equipment. Key Messages: - HERCA finds that the use of hand-held portable X-ray devices should be discouraged except in special circumstances. - As a general rule, these devices should only be used in scenarios where an intraoral radiograph is deemed necessary for a patient and the use of a fixed or semi-mobile x-ray unit is impractical, e.g.: - nursing homes, residential care facilities or homes for persons with disabilities; - forensic odontology, - military operations abroad without dental facilities

Sensing Human Activity: GPS Tracking

Science.gov (United States)

van der Spek, Stefan; van Schaick, Jeroen; de Bois, Peter; de Haan, Remco

2009-01-01

The enhancement of GPS technology enables the use of GPS devices not only as navigation and orientation tools, but also as instruments used to capture travelled routes: as sensors that measure activity on a city scale or the regional scale. TU Delft developed a process and database architecture for collecting data on pedestrian movement in three European city centres, Norwich, Rouen and Koblenz, and in another experiment for collecting activity data of 13 families in Almere (The Netherlands) for one week. The question posed in this paper is: what is the value of GPS as ‘sensor technology’ measuring activities of people? The conclusion is that GPS offers a widely useable instrument to collect invaluable spatial-temporal data on different scales and in different settings adding new layers of knowledge to urban studies, but the use of GPS-technology and deployment of GPS-devices still offers significant challenges for future research. PMID:22574061

Sensing Human Activity: GPS Tracking

Directory of Open Access Journals (Sweden)

Remco de Haan

2009-04-01

Full Text Available The enhancement of GPS technology enables the use of GPS devices not only as navigation and orientation tools, but also as instruments used to capture travelled routes: as sensors that measure activity on a city scale or the regional scale. TU Delft developed a process and database architecture for collecting data on pedestrian movement in three European city centres, Norwich, Rouen and Koblenz, and in another experiment for collecting activity data of 13 families in Almere (The Netherlands for one week. The question posed in this paper is: what is the value of GPS as ‘sensor technology’ measuring activities of people? The conclusion is that GPS offers a widely useable instrument to collect invaluable spatial-temporal data on different scales and in different settings adding new layers of knowledge to urban studies, but the use of GPS-technology and deployment of GPS-devices still offers significant challenges for future research.

GPS Satellite Simulation Facility

Data.gov (United States)

Federal Laboratory Consortium — The GPS satellite simulation facility consists of a GPS satellite simulator controlled by either a Silicon Graphics Origin 2000 or PC depending upon unit under test...

GPS Space Service Volume: Ensuring Consistent Utility Across GPS Design Builds for Space Users

Science.gov (United States)

Bauer, Frank H.; Parker, Joel Jefferson Konkl; Valdez, Jennifer Ellen

2015-01-01

GPS availability and signal strength originally specified for users on or near surface of Earth with transmitted power levels specified at edge-of-Earth, 14.3 degrees. Prior to the SSV specification, on-orbit performance of GPS varied from block build to block build (IIA, IIRM, IIF) due to antenna gain and beam width variances. Unstable on-orbit performance results in significant risk to space users. Side-lobe signals, although not specified, were expected to significantly boost GPS signal availability for users above the constellation. During GPS III Phase A, NASA noted significant discrepancies in power levels specified in GPS III specification documents, and measured on-orbit performance. To stabilize the signal for high altitude space users, NASA DoD team in 2003-2005 led the creation of new Space Service Volume (SSV) definition and specifications.

Carbonaceous species emitted from handheld two-stroke engines

Science.gov (United States)

Volckens, John; Olson, David A.; Hays, Michael D.

Small, handheld two-stroke engines used for lawn and garden work (e.g., string trimmers, leaf blowers, etc.) can emit a variety of potentially toxic carbonaceous air pollutants. Yet, the emissions effluents from these machines go largely uncharacterized, constraining the proper development of human exposure estimates, emissions inventories, and climate and air quality models. This study samples and evaluates chemical pollutant emissions from the dynamometer testing of six small, handheld spark-ignition engines—model years 1998-2002. Four oil-gas blends were tested in each engine in duplicate. Emissions of carbon dioxide, carbon monoxide, and gas-phase hydrocarbons were predominant, and the PM emitted was organic matter primarily. An ANOVA model determined that engine type and control tier contributed significantly to emissions variations across all identified compound classes; whereas fuel blend was an insignificant variable accounting for engines were generally intermediate in magnitude compared with other gasoline-powered engines, numerous compounds traditionally viewed as motor vehicle markers are also present in small engine emissions in similar relative proportions. Given that small, handheld two-stroke engines used for lawn and garden work account for 5-10% of total US emissions of CO, CO 2, NO x, HC, and PM 2.5, source apportionment models and human exposure studies need to consider the effect of these small engines on ambient concentrations in air polluted environments.

A smartphone controlled handheld microfluidic liquid handling system.

Science.gov (United States)

Li, Baichen; Li, Lin; Guan, Allan; Dong, Quan; Ruan, Kangcheng; Hu, Ronggui; Li, Zhenyu

2014-10-21

Microfluidics and lab-on-a-chip technologies have made it possible to manipulate small volume liquids with unprecedented resolution, automation and integration. However, most current microfluidic systems still rely on bulky off-chip infrastructures such as compressed pressure sources, syringe pumps and computers to achieve complex liquid manipulation functions. Here, we present a handheld automated microfluidic liquid handling system controlled by a smartphone, which is enabled by combining elastomeric on-chip valves and a compact pneumatic system. As a demonstration, we show that the system can automatically perform all the liquid handling steps of a bead-based HIV1 p24 sandwich immunoassay on a multi-layer PDMS chip without any human intervention. The footprint of the system is 6 × 10.5 × 16.5 cm, and the total weight is 829 g including battery. Powered by a 12.8 V 1500 mAh Li battery, the system consumed 2.2 W on average during the immunoassay and lasted for 8.7 h. This handheld microfluidic liquid handling platform is generally applicable to many biochemical and cell-based assays requiring complex liquid manipulation and sample preparation steps such as FISH, PCR, flow cytometry and nucleic acid sequencing. In particular, the integration of this technology with read-out biosensors may help enable the realization of the long-sought Tricorder-like handheld in vitro diagnostic (IVD) systems.

The SMS-GPS-Trip-Method

DEFF Research Database (Denmark)

Reinau, Kristian Hegner; Harder, Henrik; Weber, Michael

2015-01-01

This article presents a new method for collecting travel behavior data, based on a combination of GPS tracking and SMS technology, coined the SMS–GPS-Trip method. The state-of-the-art method for collecting data for activity based traffic models is a combination of travel diaries and GPS tracking...

GPS operations at Olkiluoto in 2009

Energy Technology Data Exchange (ETDEWEB)

Kallio, U.; Nyberg, S.; Koivula, H.; Jokela, J.; Poutanen, M.; Ahola, J. (Finnish Geodetic Institute, Masala (Finland))

2010-06-15

The GPS based deformation studies have been made at the investigation areas of Posiva since 1995, when the network of ten GPS pillars was established at Olkiluoto. One pillar in the investigation area belongs to the Finnish permanent GPS network, FinnRef. 28 GPS measurement campaigns have been carried out at Olkiluoto since 1995. According to the time series of the GPS results 1/3 of the baselines at Olkiluoto have statistically significant change rates. However, the observed movements are smaller than +-0.20 mm/a. There are five pillars, which have statistically significant horizontal velocities at Olkiluoto. These local velocity components are small but taking into account the standard deviations the largest velocity components seems to be reliably determined. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured using EDM instruments in connection to the GPS observations. Changes in he difference between the GPS and EDM results indicate the systematic change in GPS results. No corrections based on only one baseline were not applied to GPS vectors. The GPS network at Olkiluoto was extended in 2003. The new pillars were built close to Kuivalahti village and on a small island of Iso Pyrekari. According to the geological evidence it is expected that a fracture zone is located between the new stations, thus enabling the determination of possible deformations along the fracture zone. The new pillars have been observed since 2003 and now we have computed the first deformation analysis from the six years data. Four new permanent stations will be established in summer 2010 at Olkiluoto. We have automated the processing of the campaign data by using the Bernese processing engine (BPE) together with our own Perl scripts. The local crustal deformations have been studied in GeoSatakunta project, too. This GPS network is located in Cities of Pori and Rauma and their neighbouring municipalities. Two new pillars

GPS operations at Olkiluoto in 2009

International Nuclear Information System (INIS)

Kallio, U.; Nyberg, S.; Koivula, H.; Jokela, J.; Poutanen, M.; Ahola, J.

2010-06-01

The GPS based deformation studies have been made at the investigation areas of Posiva since 1995, when the network of ten GPS pillars was established at Olkiluoto. One pillar in the investigation area belongs to the Finnish permanent GPS network, FinnRef. 28 GPS measurement campaigns have been carried out at Olkiluoto since 1995. According to the time series of the GPS results 1/3 of the baselines at Olkiluoto have statistically significant change rates. However, the observed movements are smaller than ±0.20 mm/a. There are five pillars, which have statistically significant horizontal velocities at Olkiluoto. These local velocity components are small but taking into account the standard deviations the largest velocity components seems to be reliably determined. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured using EDM instruments in connection to the GPS observations. Changes in he difference between the GPS and EDM results indicate the systematic change in GPS results. No corrections based on only one baseline were not applied to GPS vectors. The GPS network at Olkiluoto was extended in 2003. The new pillars were built close to Kuivalahti village and on a small island of Iso Pyrekari. According to the geological evidence it is expected that a fracture zone is located between the new stations, thus enabling the determination of possible deformations along the fracture zone. The new pillars have been observed since 2003 and now we have computed the first deformation analysis from the six years data. Four new permanent stations will be established in summer 2010 at Olkiluoto. We have automated the processing of the campaign data by using the Bernese processing engine (BPE) together with our own Perl scripts. The local crustal deformations have been studied in GeoSatakunta project, too. This GPS network is located in Cities of Pori and Rauma and their neighbouring municipalities. Two new pillars

New portable hand-held radiation instruments for measurements and monitoring

International Nuclear Information System (INIS)

Fehlau, P.E.

1987-01-01

Hand-held radiation monitors are often used to search pedestrians and motor vehicles for special nuclear material (SNM) as part of a physical protection plan for nuclear materials. Recently, the Los Alamos Advanced Nuclear Technology group has commercialized an improved hand-held monitor that can be used for both physical-protection monitoring and verification measurements in nuclear material control and waste management. The new monitoring instruments are smaller and lighter; operate much longer on a battery charge; are available with NaI(Tl) or neutron and gamma-ray sensitive plastic scintillation detectors; and are less expensive than other comparable instruments. They also have a second operating mode for making precise measurements over counting times as long as 99 s. This mode permits making basic verification measurements that may be needed before transporting nuclear material or waste outside protected areas. Improved verification measurements can be made with a second new hand-held instrument that has a stabilized detector and three separate gamma-ray energy windows to obtain spectral information for SNM quantity, enrichment, or material-type verification

Handheld low-temperature plasma probe for portable "point-and-shoot" ambient ionization mass spectrometry.

Science.gov (United States)

Wiley, Joshua S; Shelley, Jacob T; Cooks, R Graham

2013-07-16

We describe a handheld, wireless low-temperature plasma (LTP) ambient ionization source and its performance on a benchtop and a miniature mass spectrometer. The source, which is inexpensive to build and operate, is battery-powered and utilizes miniature helium cylinders or air as the discharge gas. Comparison of a conventional, large-scale LTP source against the handheld LTP source, which uses less helium and power than the large-scale version, revealed that the handheld source had similar or slightly better analytical performance. Another advantage of the handheld LTP source is the ability to quickly interrogate a gaseous, liquid, or solid sample without requiring any setup time. A small, 7.4-V Li-polymer battery is able to sustain plasma for 2 h continuously, while the miniature helium cylinder supplies gas flow for approximately 8 continuous hours. Long-distance ion transfer was achieved for distances up to 1 m.

GPS deformation measurements at Olkiluoto in 2013

International Nuclear Information System (INIS)

Nyberg, S.; Kallio, U.; Koivula, H.

2014-08-01

The Finnish Geodetic Institute has monitored crustal deformations since mid-1990s at Olkiluoto, Kivetty and Romuvaara. The research was focused on the Olkiluoto area in 2001, when Olkiluoto was chosen to the site for the final disposal facility of the spent nuclear fuel. The work and the results of the GPS deformation monitoring at Olkiluoto in 2013 are presented. The measurement consisted of two GPS measurement campaigns, observations at local permanent stations and control markers measurements at four stations. In spring six new stations were set up for permanent tracking. In total 12 permanent stations were operating continuously from April to the end of the year. The residual time series of the stations showed periodic trends up to 3 mm in height and 1 mm in horizontal component relative to the GPS1 station. A few stations were still measured as campaign-based and analysed baseline by baseline. The data from permanent stations (GPS1-GPS9, and GPS13) were included. The analysis of the inner network based on campaign sessions showed very small motions as in previous years: 75 % of change rates are smaller than 0.10 mm/y. Roughly one third of the change rates could be considered statistically significant at 1 % significance level. Statistically significant change rates were estimated for baselines from GPS1 and GPS5. The trends and strains differed at some baselines clearly from the earlier analysis because of different troposphere modelling. The results of the outer network showed the largest difference on the baseline GPS1-GPS11 where the trend decreased from -0.42 mm/y to -0.28 mm/y. The strain pattern of the outer network shows an eastwards motion of GPS1. The estimated strains for the baselines east of GPS1 were -0.03/-0.04 ppm/y. The control marker measurements were carried at the stations GPS1, GPS2, GPS4 and GPS6. A comparison of the results with the previous measurements showed that the distance between control markers at GPS6 continues to increase. Also

GPS deformation measurements at Olkiluoto in 2013

Energy Technology Data Exchange (ETDEWEB)

Nyberg, S.; Kallio, U.; Koivula, H. [Finnish Geodetic Institute, Masala (Finland)

2014-08-15

The Finnish Geodetic Institute has monitored crustal deformations since mid-1990s at Olkiluoto, Kivetty and Romuvaara. The research was focused on the Olkiluoto area in 2001, when Olkiluoto was chosen to the site for the final disposal facility of the spent nuclear fuel. The work and the results of the GPS deformation monitoring at Olkiluoto in 2013 are presented. The measurement consisted of two GPS measurement campaigns, observations at local permanent stations and control markers measurements at four stations. In spring six new stations were set up for permanent tracking. In total 12 permanent stations were operating continuously from April to the end of the year. The residual time series of the stations showed periodic trends up to 3 mm in height and 1 mm in horizontal component relative to the GPS1 station. A few stations were still measured as campaign-based and analysed baseline by baseline. The data from permanent stations (GPS1-GPS9, and GPS13) were included. The analysis of the inner network based on campaign sessions showed very small motions as in previous years: 75 % of change rates are smaller than 0.10 mm/y. Roughly one third of the change rates could be considered statistically significant at 1 % significance level. Statistically significant change rates were estimated for baselines from GPS1 and GPS5. The trends and strains differed at some baselines clearly from the earlier analysis because of different troposphere modelling. The results of the outer network showed the largest difference on the baseline GPS1-GPS11 where the trend decreased from -0.42 mm/y to -0.28 mm/y. The strain pattern of the outer network shows an eastwards motion of GPS1. The estimated strains for the baselines east of GPS1 were -0.03/-0.04 ppm/y. The control marker measurements were carried at the stations GPS1, GPS2, GPS4 and GPS6. A comparison of the results with the previous measurements showed that the distance between control markers at GPS6 continues to increase. Also

Validity of maximal isometric knee extension strength measurements obtained via belt-stabilized hand-held dynamometry in healthy adults.

Science.gov (United States)

Ushiyama, Naoko; Kurobe, Yasushi; Momose, Kimito

2017-11-01

[Purpose] To determine the validity of knee extension muscle strength measurements using belt-stabilized hand-held dynamometry with and without body stabilization compared with the gold standard isokinetic dynamometry in healthy adults. [Subjects and Methods] Twenty-nine healthy adults (mean age, 21.3 years) were included. Study parameters involved right side measurements of maximal isometric knee extension strength obtained using belt-stabilized hand-held dynamometry with and without body stabilization and the gold standard. Measurements were performed in all subjects. [Results] A moderate correlation and fixed bias were found between measurements obtained using belt-stabilized hand-held dynamometry with body stabilization and the gold standard. No significant correlation and proportional bias were found between measurements obtained using belt-stabilized hand-held dynamometry without body stabilization and the gold standard. The strength identified using belt-stabilized hand-held dynamometry with body stabilization may not be commensurate with the maximum strength individuals can generate; however, it reflects such strength. In contrast, the strength identified using belt-stabilized hand-held dynamometry without body stabilization does not reflect the maximum strength. Therefore, a chair should be used to stabilize the body when performing measurements of maximal isometric knee extension strength using belt-stabilized hand-held dynamometry in healthy adults. [Conclusion] Belt-stabilized hand-held dynamometry with body stabilization is more convenient than the gold standard in clinical settings.

Handheld emissions detector (HED): overview and development

Science.gov (United States)

Valentino, George J.; Schimmel, David

2009-05-01

Nova Engineering, Cincinnati OH, a division of L-3 Communications (L-3 Nova), under the sponsorship of Program Manager Soldier Warrior (PM-SWAR), Fort Belvoir, VA, has developed a Soldier portable, light-weight, hand-held, geolocation sensor and processing system called the Handheld Emissions Detector (HED). The HED is a broadband custom receiver and processor that allows the user to easily sense, direction find, and locate a broad range of emitters in the user's surrounding area. Now in its second design iteration, the HED incorporates a set of COTS components that are complemented with L-3 Nova custom RF, power, digital, and mechanical components, plus custom embedded and application software. The HED user interfaces are designed to provide complex information in a readily-understandable form, thereby providing actionable results for operators. This paper provides, where possible, the top-level characteristics of the HED as well as the rationale behind its design philosophy along with its applications in both DOD and Commercial markets.

Development and testing of a scale to assess physician attitudes about handheld computers with decision support.

Science.gov (United States)

Ray, Midge N; Houston, Thomas K; Yu, Feliciano B; Menachemi, Nir; Maisiak, Richard S; Allison, Jeroan J; Berner, Eta S

2006-01-01

The authors developed and evaluated a rating scale, the Attitudes toward Handheld Decision Support Software Scale (H-DSS), to assess physician attitudes about handheld decision support systems. The authors conducted a prospective assessment of psychometric characteristics of the H-DSS including reliability, validity, and responsiveness. Participants were 82 Internal Medicine residents. A higher score on each of the 14 five-point Likert scale items reflected a more positive attitude about handheld DSS. The H-DSS score is the mean across the fourteen items. Attitudes toward the use of the handheld DSS were assessed prior to and six months after receiving the handheld device. Cronbach's Alpha was used to assess internal consistency reliability. Pearson correlations were used to estimate and detect significant associations between scale scores and other measures (validity). Paired sample t-tests were used to test for changes in the mean attitude scale score (responsiveness) and for differences between groups. Internal consistency reliability for the scale was alpha = 0.73. In testing validity, moderate correlations were noted between the attitude scale scores and self-reported Personal Digital Assistant (PDA) usage in the hospital (correlation coefficient = 0.55) and clinic (0.48), p DSS scale was reliable, valid, and responsive. The scale can be used to guide future handheld DSS development and implementation.

Handheld Computers in Education: An Industry Perspective

Science.gov (United States)

van 't Hooft, Mark; Vahey, Philip

2007-01-01

Five representatives from the mobile computing industry provide their perspectives on handhelds in education. While some of their ideas differ, they all agree on the importance of staff development, appropriate curriculum development, and teacher support to create the kinds of personalized learning environments that mobile devices make possible.

Handheld FRET-Aptamer Sensor for Water Safety, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Operational Technologies Corporation (OpTech) proposes to expand its current NASA Phase 2 SBIR handheld fluorometer and bone marker fluorescence resonance energy...

SAFARI 2000 Atmospheric Aerosol Measurements, Hand-held Hazemeters, Zambia

Data.gov (United States)

National Aeronautics and Space Administration — ABSTRACT: In conjunction with the AERONET (AErosol RObotic NETwork) participation in SAFARI 2000, the USDA Forest Service deployed handheld hazemeters in western...

Development of automatic techniques for GPS data management

International Nuclear Information System (INIS)

Park, Pil Ho

2001-06-01

It is necessary for GPS center to establish automatization as effective management of GPS network including data gathering, data transformation, data backup, data sending to IGS (International GPS Service for geodynamics), and precise ephemerides gathering. The operating program of GPS center has been adopted at KCSC (Korea Cadastral Survey Corporation), NGI (National Geography Institute), MOMAF (Ministry of Maritime Affairs and Fisheries) without self-development of core technique. The automatic management of GPS network is consists of GPS data management and data processing. It is also fundamental technique, which should be accomplished by every GPS centers. Therefore, this study carried out analyzing of Japanese GPS center, which has accomplished automatization by module considering applicability for domestic GPS centers

SAFARI 2000 Atmospheric Aerosol Measurements, Hand-held Hazemeters, Zambia

Data.gov (United States)

National Aeronautics and Space Administration — In conjunction with the AERONET (AErosol RObotic NETwork) participation in SAFARI 2000, the USDA Forest Service deployed handheld hazemeters in western Zambia from...

An Intelligent Hand-Held Microsurgical Instrument for Improved Accuracy

National Research Council Canada - National Science Library

Ang, Wei

2001-01-01

This paper presents the development and initial experimental results of the first prototype of Micron, an active hand-held instrument to sense and compensate physiological tremor and other unwanted...

GPS in Travel and Activity Surveys

DEFF Research Database (Denmark)

Nielsen, Thomas Alexander Sick; Hovgesen, Henrik Harder

2004-01-01

The use of GPS-positioning as a monitoring tool in travel and activity surveys opens up a range of possibilities. Using a personal GPS device, the locations and movements of respondents can be followed over a longer period of time. It will then be possible to analyse how the use of urban spaces...... are embedded in the wider context of activity patterns (work, school etc.). The general pattern of everyday itineraries, including route choice and time spent at different locations ?on the way? can also be analysed. If the personal GPS device is combined with an electronic questionnaire, for example...... area. The paper presents the possibilities in travel and activity surveys with GPS and electronic questionnaires. Demonstrative mapping of test data from passive GPS registration of Copenhagen respondents is presented. The different survey possibilities given a combination of GPS and PDA based...

75 FR 8400 - In the Matter of Certain Wireless Communications System Server Software, Wireless Handheld...

Science.gov (United States)

2010-02-24

... Communications System Server Software, Wireless Handheld Devices and Battery Packs; Notice of Investigation... within the United States after importation of certain wireless communications system server software... certain wireless communications system server software, wireless handheld devices or battery packs that...

The impact of legislation in Ireland on handheld mobile phone use by drivers.

LENUS (Irish Health Repository)

O'Meara, M

2008-01-01

Under the Road Traffic Act, 2006 handheld mobile phone use whilst driving is an offence liable to a fine and penalty points. The aim of this study was to determine whether there has been a change in driver behaviour following the introduction of this legislation. This study found that 2.3% of drivers were still using a handheld mobile phone.

Scintillation-Hardened GPS Receiver

Science.gov (United States)

Stephens, Donald R.

2015-01-01

CommLargo, Inc., has developed a scintillation-hardened Global Positioning System (GPS) receiver that improves reliability for low-orbit missions and complies with NASA's Space Telecommunications Radio System (STRS) architecture standards. A software-defined radio (SDR) implementation allows a single hardware element to function as either a conventional radio or as a GPS receiver, providing backup and redundancy for platforms such as the International Space Station (ISS) and high-value remote sensing platforms. The innovation's flexible SDR implementation reduces cost, weight, and power requirements. Scintillation hardening improves mission reliability and variability. In Phase I, CommLargo refactored an open-source GPS software package with Kalman filter-based tracking loops to improve performance during scintillation and also demonstrated improved navigation during a geomagnetic storm. In Phase II, the company generated a new field-programmable gate array (FPGA)-based GPS waveform to demonstrate on NASA's Space Communication and Navigation (SCaN) test bed.

75 FR 36678 - In the Matter of Certain Authentication Systems, Including Software and Handheld Electronic...

Science.gov (United States)

2010-06-28

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-697] In the Matter of Certain Authentication Systems, Including Software and Handheld Electronic Devices; Notice of Commission Decision Not to... importation of certain authentication systems, including software and handheld electronic devices, by reason...

Criteria for a comparative assessment on handheld gamma-ray measurement tools

International Nuclear Information System (INIS)

Feichtinger, J.; Schwaiger, M.; Schmitzer, C.; Kindl, P.

2001-01-01

Full text: The radionuclide laboratories at the Austrian Research Centres Seibersdorf are strongly involved in radiation protection of public and employees as well as in environmental monitoring with special concern to gamma spectrometric measurements. Hence, field measurements and therefore the subject of hand-held measurement devices is a topic of main interest. Taking into consideration, that these hand-held measurement tool are further used in critical and sensitive operations, as for example by the IAEA Safeguards or by CTBTO On-Site inspectors, a standard for characterising these gamma measurement tools seems to be sound as necessary. The poster presents a set of technical criteria as well as limiting values, which allows an objective comparison of hand-held measurement devices. The criteria can be divided into three individual parts: radiometric characteristics, ergonomics and usability in field operations. The main criteria for testing the radiometry performance of hand-held measurement devices are sensitivity, efficiency, energy response, energy resolution and nuclide identification or not identification (if necessary), detection probability, dose rate indication, uncertainty, etc. The ergonomic test contains as dominating parts handling and quality of the manual. To evaluate the applicability in field operations different environmental conditions (e.g. light conditions, temperature range, moisture...) as well as battery lifetime and weight should be taken into account. These criteria may vary in dependence of the requirements or limitations given by various external conditions, but still a standard to evaluate and will give the opportunity to provide an objective comparison. (author)

My-Mini-Pet: A Handheld Pet-Nurturing Game to Engage Students in Arithmetic Practices

Science.gov (United States)

Liao, C. C. Y.; Chen, Z-H.; Cheng, H. N. H.; Chen, F-C.; Chan, T-W.

2011-01-01

In the last decade, more and more games have been developed for handheld devices. Furthermore, the popularity of handheld devices and increase of wireless computing can be taken advantage of to provide students with more learning opportunities. Games also could bring promising benefits--specifically, motivating students to learn/play, sustaining…

How does the workload and work activities of procedural GPs compare to non-procedural GPs?

Science.gov (United States)

Russell, Deborah J; McGrail, Matthew R

2017-08-01

To investigate patterns of Australian GP procedural activity and associations with: geographical remoteness and population size hours worked in hospitals and in total; and availability for on-call DESIGN AND PARTICIPANTS: National annual panel survey (Medicine in Australia: Balancing Employment and Life) of Australian GPs, 2011-2013. Self-reported geographical work location, hours worked in different settings, and on-call availability per usual week, were analysed against GP procedural activity in anaesthetics, obstetrics, surgery or emergency medicine. Analysis of 9301 survey responses from 4638 individual GPs revealed significantly increased odds of GP procedural activity in anaesthetics, obstetrics or emergency medicine as geographical remoteness increased and community population size decreased, albeit with plateauing of the effect-size from medium-sized (population 5000-15 000) rural communities. After adjusting for confounders, procedural GPs work more hospital and more total hours each week than non-procedural GPs. In 2011 this equated to GPs practising anaesthetics, obstetrics, surgery, and emergency medicine providing 8% (95%CI 0, 16), 13% (95%CI 8, 19), 8% (95%CI 2, 15) and 18% (95%CI 13, 23) more total hours each week, respectively. The extra hours are attributable to longer hours worked in hospital settings, with no reduction in private consultation hours. Procedural GPs also carry a significantly higher burden of on-call. The longer working hours and higher on-call demands experienced by rural and remote procedural GPs demand improved solutions, such as changes to service delivery models, so that long-term procedural GP careers are increasingly attractive to current and aspiring rural GPs. © 2016 National Rural Health Alliance Inc.

Hand-held cell phone use while driving legislation and observed driver behavior among population sub-groups in the United States.

Science.gov (United States)

Rudisill, Toni M; Zhu, Motao

2017-05-12

Cell phone use behaviors are known to vary across demographic sub-groups and geographic locations. This study examined whether universal hand-held calling while driving bans were associated with lower road-side observed hand-held cell phone conversations across drivers of different ages (16-24, 25-59, ≥60 years), sexes, races (White, African American, or other), ruralities (suburban, rural, or urban), and regions (Northeast, Midwest, South, and West). Data from the 2008-2013 National Occupant Protection Use Survey were merged with states' cell phone use while driving legislation. The exposure was presence of a universal hand-held cell phone ban at time of observation. Logistic regression was used to assess the odds of drivers having a hand-held cell phone conversation. Sub-groups differences were assessed using models with interaction terms. When universal hand-held cell phone bans were effective, hand-held cell phone conversations were lower across all driver demographic sub-groups and regions. Sub-group differences existed among the sexes (p-value, phone bans, the adjusted odds ratio (aOR) of a driver hand-held phone conversation was 0.34 [95% confidence interval (CI): 0.28, 0.41] for females versus 0.47 (CI 0.40, 0.55) for males and 0.31 (CI 0.25, 0.38) for drivers in Western states compared to 0.47 (CI 0.30, 0.72) in the Northeast and 0.50 (CI 0.38, 0.66) in the South. The presence of universal hand-held cell phone bans were associated lower hand-held cell phone conversations across all driver sub-groups and regions. Hand-held phone conversations were particularly lower among female drivers and those from Western states when these bans were in effect. Public health interventions concerning hand-held cell phone use while driving could reasonably target all drivers.

Accentuated Factors of Handheld Computing

DEFF Research Database (Denmark)

Andersson, Bo; Henningsson, Stefan

The recent years of rapid development of mobile technologies creates opportunities for new user-groups in the mobile workforce to take advantage of in-formation systems (IS). However, to apprehend and harness these opportunities for mobile IS it is crucial to fully understand the user group and t......, these two steps develop the framework towards a theoretical contribution as theory for describing handheld computing from a designer’s perspective. Thirteen semi-structured interviews were made and the tentative framework was elaborated and confirmed....

Hand-held cell phone use while driving legislation and observed driver behavior among population sub-groups in the United States

Directory of Open Access Journals (Sweden)

Toni M. Rudisill

2017-05-01

Full Text Available Abstract Background Cell phone use behaviors are known to vary across demographic sub-groups and geographic locations. This study examined whether universal hand-held calling while driving bans were associated with lower road-side observed hand-held cell phone conversations across drivers of different ages (16–24, 25–59, ≥60 years, sexes, races (White, African American, or other, ruralities (suburban, rural, or urban, and regions (Northeast, Midwest, South, and West. Methods Data from the 2008–2013 National Occupant Protection Use Survey were merged with states’ cell phone use while driving legislation. The exposure was presence of a universal hand-held cell phone ban at time of observation. Logistic regression was used to assess the odds of drivers having a hand-held cell phone conversation. Sub-groups differences were assessed using models with interaction terms. Results When universal hand-held cell phone bans were effective, hand-held cell phone conversations were lower across all driver demographic sub-groups and regions. Sub-group differences existed among the sexes (p-value, <0.0001 and regions (p-value, 0.0003. Compared to states without universal hand-held cell phone bans, the adjusted odds ratio (aOR of a driver hand-held phone conversation was 0.34 [95% confidence interval (CI: 0.28, 0.41] for females versus 0.47 (CI 0.40, 0.55 for males and 0.31 (CI 0.25, 0.38 for drivers in Western states compared to 0.47 (CI 0.30, 0.72 in the Northeast and 0.50 (CI 0.38, 0.66 in the South. Conclusions The presence of universal hand-held cell phone bans were associated lower hand-held cell phone conversations across all driver sub-groups and regions. Hand-held phone conversations were particularly lower among female drivers and those from Western states when these bans were in effect. Public health interventions concerning hand-held cell phone use while driving could reasonably target all drivers.

Robust GPS autonomous signal quality monitoring

Science.gov (United States)

Ndili, Awele Nnaemeka

The Global Positioning System (GPS), introduced by the U.S. Department of Defense in 1973, provides unprecedented world-wide navigation capabilities through a constellation of 24 satellites in global orbit, each emitting a low-power radio-frequency signal for ranging. GPS receivers track these transmitted signals, computing position to within 30 meters from range measurements made to four satellites. GPS has a wide range of applications, including aircraft, marine and land vehicle navigation. Each application places demands on GPS for various levels of accuracy, integrity, system availability and continuity of service. Radio frequency interference (RFI), which results from natural sources such as TV/FM harmonics, radar or Mobile Satellite Systems (MSS), presents a challenge in the use of GPS, by posing a threat to the accuracy, integrity and availability of the GPS navigation solution. In order to use GPS for integrity-sensitive applications, it is therefore necessary to monitor the quality of the received signal, with the objective of promptly detecting the presence of RFI, and thus provide a timely warning of degradation of system accuracy. This presents a challenge, since the myriad kinds of RFI affect the GPS receiver in different ways. What is required then, is a robust method of detecting GPS accuracy degradation, which is effective regardless of the origin of the threat. This dissertation presents a new method of robust signal quality monitoring for GPS. Algorithms for receiver autonomous interference detection and integrity monitoring are demonstrated. Candidate test statistics are derived from fundamental receiver measurements of in-phase and quadrature correlation outputs, and the gain of the Active Gain Controller (AGC). Performance of selected test statistics are evaluated in the presence of RFI: broadband interference, pulsed and non-pulsed interference, coherent CW at different frequencies; and non-RFI: GPS signal fading due to physical blockage and

Tracking Small Satellites using Translated GPS

OpenAIRE

Lefevre, Don; Mulally, Daniel

1991-01-01

This paper discusses using translated GPS for tracking small satellites, the technical trade-offs involved, and the position and timing accuracies which are achievable using translated GPS. The Global Positioning System (GPS) uses the relative times-of-arrival of multiple spread-spectrum signals at an antenna to determine the position of the antenna. The system can also determine the time the antenna was at that position. The direct sequence spread spectrum signals are transmitted from GPS sa...

Acute pain management efficiency improves with point-of-care handheld electronic billing system.

Science.gov (United States)

Fahy, Brenda G

2009-02-01

Technology advances continue to impact patient care and physician workflow. To enable more efficient performance of billing activities, a point-of-care (POC) handheld computer technology replaced a paper-based system on an acute pain management service. Using a handheld personal digital assistant (PDA) and software from MDeverywhere (MDe, MDeverywhere, Long Island, NY), we performed a 1-yr prospective observational study of an anesthesiology acute pain management service billings and collections. Seventeen anesthesiologists providing billable acute pain services were trained and entered their charges on a PDA. Twelve months of data, just before electronic implementation (pre-elec), were compared to a 12-m period after implementation (post-elec). The total charges were 4883 for 890 patients pre-elec and 5368 for 1128 patients post-elec. With adoption of handheld billing, the charge lag days decreased from 29.3 to 7.0 (P billing using PDAs to replace a paper-based billing system improved the collection rate and decreased the number of charge lag days with a positive return on investment. The handheld PDA billing system provided POC support for physicians during their daily clinical (e.g., patient locations, rounding lists) and billing activities, improving workflow.

Epilepsy Forewarning Using A Hand-Held Device

Energy Technology Data Exchange (ETDEWEB)

Hively, LM

2005-02-21

Over the last decade, ORNL has developed and patented a novel approach for forewarning of a large variety of machine and biomedical events. The present implementation uses desktop computers to analyze archival data. This report describes the next logical step in this effort, namely use of a hand-held device for the analysis.

Evidential recovery from GPS devices

Directory of Open Access Journals (Sweden)

Brian Cusack

Full Text Available Global Positioning Systems (GPS have become more affordable, are now widely used in motor vehicles and in other frequently used applications. As a consequence GPS are increasingly becoming an important source of evidential data for digital forensic investigations. This paper acknowledges there are only disparate documents for the guidance of an investigator when extracting evidence form such systems. The focus of this paper is to provide the technical details of recovering artifacts from four GPS currently available to the New Zealand market. Navman brand GPS are used, following a forensically robust process. The steps of the process are described, results analysed and the associated risks are discussed. In addition, the paper discusses techniques related to the visual presentation of evidence suitable for Google Maps. Automation attempts to speed up the analysis to visualization steps are also included. The outcome is a road map that may assist digital forensic investigators develop GPS examination strategies for implementation in their own organizations.

Deformation of the Japanese Islands and seismic coupling: an interpretation based on GSI permanent GPS observations

Science.gov (United States)

Le Pichon, Xavier; Mazzotti, Stéphane; Henry, Pierre; Hashimoto, Manabu

1998-08-01

The entire area of the Japanese Islands has been covered by the permanent GPS observation network of the Geographical Survey Institute since 1994. In this paper we use a solution for the vectors of motion during 1995 for a selection of 116 stations to discuss the origin of the observed deformation field. We refer the displacement field to Eurasia using the VLBI-determined motion of Kashima and demonstrate that other choices such as the Okhotsk or North American plates for north Japan are not compatible with the data. 1 yr GPS velocities are much higher than geological constraints would allow because these short-term measurements include transient elastic deformation. However, the good qualitative agreement between the observed geodetic deformation tensors and those inferred from active faults and earthquakes suggests that the Quaternary permanent deformation is essentially the result of the transfer of part of the subduction-induced elastic deformation into permanent plastic deformation. We then compute the elastic deformation of the Japanese Islands caused by interseismic loading of the Pacific and Philippine subduction planes. The geometry of the coupled zone and its downward extension are determined from the distribution of earthquakes for the Pacific slab. For the Philippine slab we use the geometry proposed by Hyndman et al. (1995). These elastic models account for most of the observed velocity field if the subduction movement of the Philippine Sea Plate is 100 per cent locked and if that of the Pacific Plate is 75-85 per cent locked. We note that the boundaries of the areas where significant elastic deformation is predicted (more than 10 mm yr-1 of motion with respect to Eurasia) coincide with the main zones of permanent deformation: the Eastern Japan Sea deformation zone for the Pacific subduction elastic deformation field and the Setouchi/MTL deformation zone for the Nankai field. Each zone probably accommodates 10-15 mm yr-1 of motion in the long term

Applications of GPS technologies to field sports.

Science.gov (United States)

Aughey, Robert J

2011-09-01

Global positioning system (GPS) technology was made possible after the invention of the atomic clock. The first suggestion that GPS could be used to assess the physical activity of humans followed some 40 y later. There was a rapid uptake of GPS technology, with the literature concentrating on validation studies and the measurement of steady-state movement. The first attempts were made to validate GPS for field sport applications in 2006. While GPS has been validated for applications for team sports, some doubts continue to exist on the appropriateness of GPS for measuring short high-velocity movements. Thus, GPS has been applied extensively in Australian football, cricket, hockey, rugby union and league, and soccer. There is extensive information on the activity profile of athletes from field sports in the literature stemming from GPS, and this includes total distance covered by players and distance in velocity bands. Global positioning systems have also been applied to detect fatigue in matches, identify periods of most intense play, different activity profiles by position, competition level, and sport. More recent research has integrated GPS data with the physical capacity or fitness test score of athletes, game-specific tasks, or tactical or strategic information. The future of GPS analysis will involve further miniaturization of devices, longer battery life, and integration of other inertial sensor data to more effectively quantify the effort of athletes.

Linking GPS Telemetry Surveys and Scat Analyses Helps Explain Variability in Black Bear Foraging Strategies.

Science.gov (United States)

Lesmerises, Rémi; Rebouillat, Lucie; Dussault, Claude; St-Laurent, Martin-Hugues

2015-01-01

Studying diet is fundamental to animal ecology and scat analysis, a widespread approach, is considered a reliable dietary proxy. Nonetheless, this method has weaknesses such as non-random sampling of habitats and individuals, inaccurate evaluation of excretion date, and lack of assessment of inter-individual dietary variability. We coupled GPS telemetry and scat analyses of black bears Ursus americanus Pallas to relate diet to individual characteristics and habitat use patterns while foraging. We captured 20 black bears (6 males and 14 females) and fitted them with GPS/Argos collars. We then surveyed GPS locations shortly after individual bear visits and collected 139 feces in 71 different locations. Fecal content (relative dry matter biomass of ingested items) was subsequently linked to individual characteristics (sex, age, reproductive status) and to habitats visited during foraging bouts using Brownian bridges based on GPS locations prior to feces excretion. At the population level, diet composition was similar to what was previously described in studies on black bears. However, our individual-based method allowed us to highlight different intra-population patterns, showing that sex and female reproductive status had significant influence on individual diet. For example, in the same habitats, females with cubs did not use the same food sources as lone bears. Linking fecal content (i.e., food sources) to habitat previously visited by different individuals, we demonstrated a potential differential use of similar habitats dependent on individual characteristics. Females with cubs-of-the-year tended to use old forest clearcuts (6-20 years old) to feed on bunchberry, whereas females with yearling foraged for blueberry and lone bears for ants. Coupling GPS telemetry and scat analyses allows for efficient detection of inter-individual or inter-group variations in foraging strategies and of linkages between previous habitat use and food consumption, even for cryptic

Linking GPS Telemetry Surveys and Scat Analyses Helps Explain Variability in Black Bear Foraging Strategies.

Directory of Open Access Journals (Sweden)

Rémi Lesmerises

Full Text Available Studying diet is fundamental to animal ecology and scat analysis, a widespread approach, is considered a reliable dietary proxy. Nonetheless, this method has weaknesses such as non-random sampling of habitats and individuals, inaccurate evaluation of excretion date, and lack of assessment of inter-individual dietary variability. We coupled GPS telemetry and scat analyses of black bears Ursus americanus Pallas to relate diet to individual characteristics and habitat use patterns while foraging. We captured 20 black bears (6 males and 14 females and fitted them with GPS/Argos collars. We then surveyed GPS locations shortly after individual bear visits and collected 139 feces in 71 different locations. Fecal content (relative dry matter biomass of ingested items was subsequently linked to individual characteristics (sex, age, reproductive status and to habitats visited during foraging bouts using Brownian bridges based on GPS locations prior to feces excretion. At the population level, diet composition was similar to what was previously described in studies on black bears. However, our individual-based method allowed us to highlight different intra-population patterns, showing that sex and female reproductive status had significant influence on individual diet. For example, in the same habitats, females with cubs did not use the same food sources as lone bears. Linking fecal content (i.e., food sources to habitat previously visited by different individuals, we demonstrated a potential differential use of similar habitats dependent on individual characteristics. Females with cubs-of-the-year tended to use old forest clearcuts (6-20 years old to feed on bunchberry, whereas females with yearling foraged for blueberry and lone bears for ants. Coupling GPS telemetry and scat analyses allows for efficient detection of inter-individual or inter-group variations in foraging strategies and of linkages between previous habitat use and food consumption, even

Clinical translation of handheld optical coherence tomography: practical considerations and recent advancements

Science.gov (United States)

Monroy, Guillermo L.; Won, Jungeun; Spillman, Darold R.; Dsouza, Roshan; Boppart, Stephen A.

2017-12-01

Since the inception of optical coherence tomography (OCT), advancements in imaging system design and handheld probes have allowed for numerous advancements in disease diagnostics and characterization of the structural and optical properties of tissue. OCT system developers continue to reduce form factor and cost, while improving imaging performance (speed, resolution, etc.) and flexibility for applicability in a broad range of fields, and nearly every clinical specialty. An extensive array of components to construct customized systems has also become available, with a range of commercial entities that produce high-quality products, from single components to full systems, for clinical and research use. Many advancements in the development of these miniaturized and portable systems can be linked back to a specific challenge in academic research, or a clinical need in medicine or surgery. Handheld OCT systems are discussed and explored for various applications. Handheld systems are discussed in terms of their relative level of portability and form factor, with mention of the supporting technologies and surrounding ecosystem that bolstered their development. Additional insight from our efforts to implement systems in several clinical environments is provided. The trend toward well-designed, efficient, and compact handheld systems paves the way for more widespread adoption of OCT into point-of-care or point-of-procedure applications in both clinical and commercial settings.

Evaluation of an enclosed ultraviolet-C radiation device for decontamination of mobile handheld devices.

Science.gov (United States)

Mathew, J Itty; Cadnum, Jennifer L; Sankar, Thriveen; Jencson, Annette L; Kundrapu, Sirisha; Donskey, Curtis J

2016-06-01

Mobile handheld devices used in health care settings may become contaminated with health care-associated pathogens. We demonstrated that an enclosed ultraviolet-C radiation device was effective in rapidly reducing methicillin-resistant Staphylococcus aureus, and with longer exposure times, Clostridium difficile spores, on glass slides and reducing contamination on in-use mobile handheld devices. Published by Elsevier Inc.

Agreement Between an Automated Volume Breast Scanner and Handheld Ultrasound for Diagnostic Breast Examinations.

Science.gov (United States)

Barr, Richard G; DeVita, Robert; Destounis, Stamatia; Manzoni, Federica; De Silvestri, Annalisa; Tinelli, Carmine

2017-10-01

To compare the agreement and interobserver variability of diagnostic handheld ultrasound (US) and a single volume on an automated breast volume scanner (ABVS) and to determine whether there was a significant difference if the ABVS was used by a sonographer or mammographic technologist. Ninety patients scheduled for diagnostic US examinations were randomized to either handheld US or the ABVS first. The AVBS was randomized between a sonographer and a mammographic technologist performing the study. The studies were blinded, randomized, and read by 2 radiologists. The lesion with the highest Breast Imaging Reporting and Data System (BI-RADS) score was used in the analysis. Final diagnoses were made by core biopsy or follow-up for 2 years. Lesions included 9 malignant and 81 benign. The 90 patients had a mean age ± SD of 53.1 ± 16.3 years. The κ value for agreement between the ABVS and handheld US was 0.831 (95% confidence interval, 0.744-0.925), whereas the global agreement for a 7-point BI-RADS score was 0.488 (0.372-0.560). The agreement between the ABVS and handheld US was nearly the same when the ABVS was used by a mammographic technologist (κ = 0.858 [0.723-0.963]) or sonographer (κ = 0.803 [0.596-1.000]; P = .47). The areas under the receiver operating characteristic curves for characterization by the ABVS were 0.91 (0.84-0.96) for reader 1 and 0.91 (0.83-0.96) for reader 2; those for handheld US were 0.91 (0.84-0.96) for reader 1 and 0.83 (0.74-0.90) for reader 2, with no statistical difference. The agreement based on pathologic images was κ = 0.831 (0.718-0.944); for handheld US, κ = 0.795 (0.623-0.967); and for the AVBS, κ = 0.869 (0.725-1.000). Performing a single-view diagnostic ABVS examination has good agreement with a handheld diagnostic US workup. There is no difference if the ABVS is used by a sonographer or mammographic technologist. © 2017 by the American Institute of Ultrasound in Medicine.

Kinematic-PPP using Single/Dual Frequency Observations from (GPS, GLONASS and GPS/GLONASS) Constellations for Hydrography

Science.gov (United States)

Farah, Ashraf

2018-03-01

Global Positioning System (GPS) technology is ideally suited for inshore and offshore positioning because of its high accuracy and the short observation time required for a position fix. Precise point positioning (PPP) is a technique used for position computation with a high accuracy using a single GNSS receiver. It relies on highly accurate satellite position and clock data that can be acquired from different sources such as the International GNSS Service (IGS). PPP precision varies based on positioning technique (static or kinematic), observations type (single or dual frequency) and the duration of observations among other factors. PPP offers comparable accuracy to differential GPS with safe in cost and time. For many years, PPP users depended on GPS (American system) which considered the solely reliable system. GLONASS's contribution in PPP techniques was limited due to fail in maintaining full constellation. Yet, GLONASS limited observations could be integrated into GPS-based PPP to improve availability and precision. As GLONASS reached its full constellation early 2013, there is a wide interest in PPP systems based on GLONASS only and independent of GPS. This paper investigates the performance of kinematic PPP solution for the hydrographic applications in the Nile river (Aswan, Egypt) based on GPS, GLONASS and GPS/GLONASS constellations. The study investigates also the effect of using two different observation types; single-frequency and dual frequency observations from the tested constellations.

Leakage and scattered radiation from hand-held dental x-ray unit

International Nuclear Information System (INIS)

Kim, Eun Kyung

2007-01-01

To compare the leakage and scattered radiation from hand-held dental X-ray unit with radiation from fixed dental X-ray unit. For evaluation we used one hand-held dental X-ray unit and Oramatic 558 (Trophy Radiologie, France), a fixed dental X-ray unit. Doses were measured with Unfors Multi-O-Meter 512L at the right and left hand levels of X-ray tube head part for the scattered and leakage radiation when human skull DXTTR ΙΙΙ was exposed to both dental X-ray units. And for the leakage radiation only, doses were measured at the immediately right, left, superior and posterior side of the tube head part when air was exposed. Exposure parameters of hand-held dental X-ray unit were 70 kVp, 3 mA , 0.1 second, and of fixed X-ray unit 70 kVp, 8 mA, 0.45 second. The mean dose at the hand level when human skull DXTTR ΙΙΙ was exposed with portable X-ray unit 6.39 μGy, and the mean dose with fixed X-ray unit 3.03 μGy (p<0.001). The mean dose at the immediate side of the tube head part when air was exposed with portable X-ray unit was 2.97 μGy and with fixed X-ray unit the mean dose was 0.68 μGy (p<0.01). The leakage and scattered radiation from hand-held dental radiography was greater than from fixed dental radiography

Leakage and scattered radiation from hand-held dental x-ray unit

Energy Technology Data Exchange (ETDEWEB)

Kim, Eun Kyung [Dankook Univ. School of Dentistry, Seoul (Korea, Republic of)

2007-06-15

To compare the leakage and scattered radiation from hand-held dental X-ray unit with radiation from fixed dental X-ray unit. For evaluation we used one hand-held dental X-ray unit and Oramatic 558 (Trophy Radiologie, France), a fixed dental X-ray unit. Doses were measured with Unfors Multi-O-Meter 512L at the right and left hand levels of X-ray tube head part for the scattered and leakage radiation when human skull DXTTR {iota}{iota}{iota} was exposed to both dental X-ray units. And for the leakage radiation only, doses were measured at the immediately right, left, superior and posterior side of the tube head part when air was exposed. Exposure parameters of hand-held dental X-ray unit were 70 kVp, 3 mA , 0.1 second, and of fixed X-ray unit 70 kVp, 8 mA, 0.45 second. The mean dose at the hand level when human skull DXTTR {iota}{iota}{iota} was exposed with portable X-ray unit 6.39 {mu}Gy, and the mean dose with fixed X-ray unit 3.03 {mu}Gy (p<0.001). The mean dose at the immediate side of the tube head part when air was exposed with portable X-ray unit was 2.97 {mu}Gy and with fixed X-ray unit the mean dose was 0.68 {mu}Gy (p<0.01). The leakage and scattered radiation from hand-held dental radiography was greater than from fixed dental radiography.

GPS Ephemeris Message Broadcast Simulation

National Research Council Canada - National Science Library

Browne, Nathan J; Light, James J

2005-01-01

The warfighter constantly needs increased accuracy from GPS and a means to increasing this accuracy to the decimeter level is a broadcast ephemeris message containing GPS satellite orbit and clock corrections...

Integration of GPS precise point positioning and MEMS-based INS using unscented particle filter.

Science.gov (United States)

Abd Rabbou, Mahmoud; El-Rabbany, Ahmed

2015-03-25

Integration of Global Positioning System (GPS) and Inertial Navigation System (INS) integrated system involves nonlinear motion state and measurement models. However, the extended Kalman filter (EKF) is commonly used as the estimation filter, which might lead to solution divergence. This is usually encountered during GPS outages, when low-cost micro-electro-mechanical sensors (MEMS) inertial sensors are used. To enhance the navigation system performance, alternatives to the standard EKF should be considered. Particle filtering (PF) is commonly considered as a nonlinear estimation technique to accommodate severe MEMS inertial sensor biases and noise behavior. However, the computation burden of PF limits its use. In this study, an improved version of PF, the unscented particle filter (UPF), is utilized, which combines the unscented Kalman filter (UKF) and PF for the integration of GPS precise point positioning and MEMS-based inertial systems. The proposed filter is examined and compared with traditional estimation filters, namely EKF, UKF and PF. Tightly coupled mechanization is adopted, which is developed in the raw GPS and INS measurement domain. Un-differenced ionosphere-free linear combinations of pseudorange and carrier-phase measurements are used for PPP. The performance of the UPF is analyzed using a real test scenario in downtown Kingston, Ontario. It is shown that the use of UPF reduces the number of samples needed to produce an accurate solution, in comparison with the traditional PF, which in turn reduces the processing time. In addition, UPF enhances the positioning accuracy by up to 15% during GPS outages, in comparison with EKF. However, all filters produce comparable results when the GPS measurement updates are available.

Handheld computers for self-administered sensitive data collection: A comparative study in Peru

Directory of Open Access Journals (Sweden)

Hughes James P

2008-03-01

Full Text Available Abstract Background Low-cost handheld computers (PDA potentially represent an efficient tool for collecting sensitive data in surveys. The goal of this study is to evaluate the quality of sexual behavior data collected with handheld computers in comparison with paper-based questionnaires. Methods A PDA-based program for data collection was developed using Open-Source tools. In two cross-sectional studies, we compared data concerning sexual behavior collected with paper forms to data collected with PDA-based forms in Ancon (Lima. Results The first study enrolled 200 participants (18–29 years. General agreement between data collected with paper format and handheld computers was 86%. Categorical variables agreement was between 70.5% and 98.5% (Kappa: 0.43–0.86 while numeric variables agreement was between 57.1% and 79.8% (Spearman: 0.76–0.95. Agreement and correlation were higher in those who had completed at least high school than those with less education. The second study enrolled 198 participants. Rates of responses to sensitive questions were similar between both kinds of questionnaires. However, the number of inconsistencies (p = 0.0001 and missing values (p = 0.001 were significantly higher in paper questionnaires. Conclusion This study showed the value of the use of handheld computers for collecting sensitive data, since a high level of agreement between paper and PDA responses was reached. In addition, a lower number of inconsistencies and missing values were found with the PDA-based system. This study has demonstrated that it is feasible to develop a low-cost application for handheld computers, and that PDAs are feasible alternatives for collecting field data in a developing country.

Monitoring of WEEE plastics in regards to brominated flame retardants using handheld XRF

Energy Technology Data Exchange (ETDEWEB)

Aldrian, Alexia, E-mail: alexia.aldrian@unileoben.ac.at [Chair of Waste Processing Technology and Waste Management, Montanuniversitaet Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria); Ledersteger, Alfred, E-mail: a.ledersteger@saubermacher.at [Saubermacher Dienstleistungs AG, Hans-Roth-Straße 1, 8073 Feldkirchen bei Graz (Austria); Pomberger, Roland, E-mail: roland.pomberger@unileoben.ac.at [Chair of Waste Processing Technology and Waste Management, Montanuniversitaet Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria)

2015-02-15

Highlights: • Specification of an empirical factor for conversion from bromine to PBB and PBDE. • The handheld XRF device was validated for this particular application. • A very large number of over 4600 pieces of monitor housings was analysed. • The recyclable fraction mounts up to 85% for TV but only 53% of PC waste plastics. • A high percentage of pieces with bromine contents of over 50,000 ppm was obtained. - Abstract: This contribution is focused on the on-site determination of the bromine content in waste electrical and electronic equipment (WEEE), in particular waste plastics from television sets (TV) and personal computer monitors (PC) using a handheld X-ray fluorescence (XRF) device. The described approach allows the examination of samples in regards to the compliance with legal specifications for polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) directly after disassembling and facilitates the sorting out of plastics with high contents of brominated flame retardants (BFRs). In all, over 3000 pieces of black (TV) and 1600 pieces of grey (PC) plastic waste were analysed with handheld XRF technique for this study. Especially noticeable was the high percentage of pieces with a bromine content of over 50,000 ppm for TV (7%) and PC (39%) waste plastics. The applied method was validated by comparing the data of handheld XRF with results obtained by GC–MS. The results showed the expected and sufficiently accurate correlation between these two methods. It is shown that handheld XRF technique is an effective tool for fast monitoring of large volumes of WEEE plastics in regards to BFRs for on-site measurements.

Human Handheld-Device Interaction : An Adaptive User Interface

NARCIS (Netherlands)

Fitrianie, S.

2010-01-01

The move to smaller, lighter and more powerful (mobile) handheld devices, whe-ther PDAs or smart-phones, looks like a trend that is building up speed. With numerous embedded technologies and wireless connectivity, the drift opens up unlimited opportunities in daily activities that are both more

Implementing GPS into Pave-IR.

Science.gov (United States)

2009-03-01

To further enhance the capabilities of the Pave-IR thermal segregation detection system developed at the Texas Transportation Institute, researchers incorporated global positioning system (GPS) data collection into the thermal profiles. This GPS capa...

Hand-held electronic data collection and procedure environment

International Nuclear Information System (INIS)

Kennedy, E.; Doniz, K.

1996-01-01

As part of a CANDU Owners Group project, AECL has developed a hand-held electronic data collection and procedure environment. Integral to this environment is the C omputerized Procedure Engine . The development of the CPE allows operators, maintainers, and technical support staff to execute virtually any type of station procedure on a general-purpose PC-compatible hand-held computer. There are several advantages to using the computerized procedures: less paper use and handling, reduction in human error, reduction in rework in the field, an increase in procedural compliance, and immediate availability of data to download to databases and plant information systems. The paper describes: the advantages of using computerized procedures, why early forms of computerized procedures were inadequate, the features that the C omputerized Procedure Engine o ffers to the user, the streamlined life cycle of a computerized procedure, and field experience. The paper concludes that computerized procedures are ready for pilot applications at stations. (author)

Measuring thyroid uptake with hand-held radiation monitors

International Nuclear Information System (INIS)

Deschamps, M.

1987-04-01

With the use of Iodine 123, 125 and 131 and some compounds of Technetium-99 m, a fraction of the isotopes can be trapped in the thyroid of the technicians. We used the hand-held radiation contamination or survey meters of the nine (9) Nuclear medicine departments we visited to see if they were adequate for the evaluation of thyroid uptake of the users. Measurements on a neck-phanton helped us to determine a minimum detectable activity for each isotope. We were then able to check if the measurements of investigations and action levels were possible. None of the hand-held radiation monitors are completely satisfactory for the measure of thyroid uptake of the user. We discuss a class of equipment capable of measuring radiation emissions at the investigation level. Measurement at the action level is possible with meters having scintillation or proportional probes but none of them permits the discrimination in energy required for a quantitative evaluation of the radioisotopes used

GPS measurements in Satakunta area

International Nuclear Information System (INIS)

Poutanen, M.; Nyberg, S.; Ahola, J.

2010-10-01

The Finnish Geodetic Institute, the Geological Survey of Finland, Posiva Ltd and municipalities in the district of Satakunta launched the GeoSatakunta research program in 2002 to carry out interdisciplinary studies on regional bedrock stress field and to apply the results e.g. in land use planning in the Satakunta area. The area was chosen for many reasons. Its geological diversity, extensive multi-disciplinary data coverage, and various interests of participants made the area suitable for the project. The purpose of the GPS observations is to get detailed information on recent crustal deformations in the area. The Finnish Geodetic Institute maintains e.g. national GPS network, FinnRef, and since 1995 a local research network in the Olkiluoto area. The Satakunta network differs from these, and this is the first time to obtain such detailed information of a regional network in Finland. The Satakunta GPS network consists of 13 concrete pillars for episodic GPS campaigns and the Olkiluoto permanent GPS station in the FinnRef network. The distances between the concrete pillars are 10-15 km, and the sites were chosen in a co-operation with the Geological Survey of Finland taking into account the geological structures in the area. The City of Pori made the final reconnaissance in the field and constructed eight pillars in 2003. The original network was expanded in 2005-2006 in Eurajoki and Rauma, and at the City of Rauma joined the co-operation. The five new pillars join the previous Olkiluoto network into the Satakunta network. There have been three annual GPS campaigns in 2003-2008. Time series of the Satakunta network are shorter than in the Olkiluoto network, and also the distances are longer. Therefore, the same accuracy than in Olkiluoto has not yet achieved. However, mm-sized movements can be excluded. Estimated velocities were small (0.2 mm/a) and mostly statistically insignificant because of relatively short time series. In this publication we describe the

GPS Navigation and Tracking Device

Directory of Open Access Journals (Sweden)

Yahya Salameh Khraisat

2011-10-01

Full Text Available Since the introduction of GPS Navigation systems in the marketplace, consumers and businesses have been coming up with innovative ways to use the technology in their everyday life. GPS Navigation and Tracking systems keep us from getting lost when we are in strange locations, they monitor children when they are away from home, keep track of business vehicles and can even let us know where a philandering partner is at all times. Because of this we attend to build a GPS tracking device to solve the mentioned problems. Our work consists of the GPS module that collects data from satellites and calculates the position information before transmitting them to the user’s PC (of Navigation system or observers (of Tracking System using wireless technology (GSM.

Derivation of some geometric parameters from GPS measurements

Directory of Open Access Journals (Sweden)

Marcel Mojzeš

2005-11-01

Full Text Available Combining GPS and terrestrial data requires a common coordinate system. When the original GPS vectors do not form a network, the 3D network adjustment can not be performed. In this case, in order to integrate the GPS measurements with the terrestrial observations and to perform a combined network adjustment, the GPS measurements should be transformed to this common system. The GPS measurements which are the usual output of the GPS post processing softwares are based on the WGS84 ellipsoid and the S-JTSK local datum is based on the Bessel ellipsoid. Thus, the reduction of measurements to the S-JTSK mapping plane can not be started from the measurements resulting from GPS post processing softwares because GPS and S-JTSK don’t have the same ellipsoid. Another view of this reduction will be described in this paper.

The GPS Laser Retroreflector Array Project

Science.gov (United States)

Merkowitz, Stephen M.

2012-01-01

Systematic co-location in space through the precision orbit determination of GPS satellites via satellite laser ranging will contribute significantly towards improving the accuracy and stability of the international terrestrial reference frame. NASA recently formed the GPS Laser Retroreflector Array Project to develop and deliver retroreflectors for integration on the next generation of GPS satellites. These retroreflectors will be an important contributor to achieving a global accuracy of 1.0 mm and 0.1 mm/year stability in the international terrestrial reference frame. We report here the current status of the GPS Laser Retroreflector Array Project.

GPS Water Vapor Tomography Based on Accurate Estimations of the GPS Tropospheric Parameters

Science.gov (United States)

Champollion, C.; Masson, F.; Bock, O.; Bouin, M.; Walpersdorf, A.; Doerflinger, E.; van Baelen, J.; Brenot, H.

2003-12-01

The Global Positioning System (GPS) is now a common technique for the retrieval of zenithal integrated water vapor (IWV). Further applications in meteorology need also slant integrated water vapor (SIWV) which allow to precisely define the high variability of tropospheric water vapor at different temporal and spatial scales. Only precise estimations of IWV and horizontal gradients allow the estimation of accurate SIWV. We present studies developed to improve the estimation of tropospheric water vapor from GPS data. Results are obtained from several field experiments (MAP, ESCOMPTE, OHM-CV, IHOP, .). First IWV are estimated using different GPS processing strategies and results are compared to radiosondes. The role of the reference frame and the a priori constraints on the coordinates of the fiducial and local stations is generally underestimated. It seems to be of first order in the estimation of the IWV. Second we validate the estimated horizontal gradients comparing zenith delay gradients and single site gradients. IWV, gradients and post-fit residuals are used to construct slant integrated water delays. Validation of the SIWV is under progress comparing GPS SIWV, Lidar measurements and high resolution meteorological models (Meso-NH). A careful analysis of the post-fit residuals is needed to separate tropospheric signal from multipaths. The slant tropospheric delays are used to study the 3D heterogeneity of the troposphere. We develop a tomographic software to model the three-dimensional distribution of the tropospheric water vapor from GPS data. The software is applied to the ESCOMPTE field experiment, a dense network of 17 dual frequency GPS receivers operated in southern France. Three inversions have been successfully compared to three successive radiosonde launches. Good resolution is obtained up to heights of 3000 m.

Handheld Universal Diagnostic Sensor

Science.gov (United States)

Chan, Eugene

2012-01-01

The rHEALTH technology is designed to shrink an entire hospital testing laboratory onto a handheld device. A physician or healthcare provider performs the test by collecting a fingerstick of blood from a patient. The tiny volume of blood is inserted into the rHEALTH device. Inside the device is a microfluidic chip that contains small channels about the width of a human hair. These channels help move the blood and analyze the blood sample. The rHEALTH sensor uses proprietary reagents called nanostrips, which are nanoscale test strips that enable the clinical assays. The readout is performed by laser-induced fluorescence. Overall, the time from blood collection through analysis is less than a minute.

Precise GPS orbits for geodesy

Science.gov (United States)

Colombo, Oscar L.

1994-01-01

The Global Positioning System (GPS) has become, in recent years, the main space-based system for surveying and navigation in many military, commercial, cadastral, mapping, and scientific applications. Better receivers, interferometric techniques (DGPS), and advances in post-processing methods have made possible to position fixed or moving receivers with sub-decimeter accuracies in a global reference frame. Improved methods for obtaining the orbits of the GPS satellites have played a major role in these achievements; this paper gives a personal view of the main developments in GPS orbit determination.

GPS on Every Roof, GPS Sensor Network for Post-Seismic Building-Wise Damage Identification

Directory of Open Access Journals (Sweden)

Kenji Oguni

2013-12-01

Full Text Available Development of wireless sensor network equipped with GPS for post-seismic building-wise damage identification is presented in this paper. This system is called GPS on Every Roof. Sensor node equipped with GPS antenna and receiver is installed on the top of the roof of each and every building. The position of this sensor node is measured before and after earthquake. The final goal of this system is to i identify the displacement of the roof of each house and ii collect the information of displacement of the roof of the houses through wireless communication. Superposing this information on GIS, building-wise damage distribution due to earthquake can be obtained. The system overview, hardware and some of the key components of the system such as on-board GPS relative positioning algorithm to achieve the accuracy in the order of several centimeters are described in detail. Also, the results from a field experiment using a wireless sensor network with 39 sensor nodes are presented.

GPS satellite surveying

CERN Document Server

Leick, Alfred; Tatarnikov, Dmitry

2015-01-01

THE MOST COMPREHENSIVE, UP-TO-DATE GUIDE ON GPS TECHNOLOGY FOR SURVEYING Three previous editions have established GPS Satellite Surveying as the definitive industry reference. Now fully updated and expanded to reflect the newest developments in the field, this Fourth Edition features cutting-edge information on GNSS antennas, precise point positioning, real-time relative positioning, lattice reduction, and much more. Expert authors examine additional tools and applications, offering complete coverage of geodetic surveying using satellite technologies. The past decade has seen a major evolut

Application of Handheld Laser-Induced Breakdown Spectroscopy (LIBS) to Geochemical Analysis.

Science.gov (United States)

Connors, Brendan; Somers, Andrew; Day, David

2016-05-01

While laser-induced breakdown spectroscopy (LIBS) has been in use for decades, only within the last two years has technology progressed to the point of enabling true handheld, self-contained instruments. Several instruments are now commercially available with a range of capabilities and features. In this paper, the SciAps Z-500 handheld LIBS instrument functionality and sub-systems are reviewed. Several assayed geochemical sample sets, including igneous rocks and soils, are investigated. Calibration data are presented for multiple elements of interest along with examples of elemental mapping in heterogeneous samples. Sample preparation and the data collection method from multiple locations and data analysis are discussed. © The Author(s) 2016.

The GPS odograph user's guide

Science.gov (United States)

The GPS-based Odograph Prototype (GOP or GPS Odograph) was developed in an effort sponsored by The Federal Highway Administration (FHWA). The purpose of this effort was to develop a means of using inexpensive commercial off-the-self laptop (or notebo...

High Gain Advanced GPS Receiver

National Research Council Canada - National Science Library

Brown, Alison; Zhang, Gengsheng

2006-01-01

NAVSYS High Gain Advanced GPS Receiver (HAGR) uses a digital beam-steering antenna array to enable up to eight GPS satellites to be tracked, each with up to 10 dBi of additional antenna gain over a conventional receiver solution...

Exploring streamwater mixing dynamics via handheld thermal infrared imagery

NARCIS (Netherlands)

Antonelli, Marta; Klaus, Julian; Smettem, Keith; Teuling, Ryan; Pfister, Laurent

2017-01-01

Stream confluences are important hotspots of aquatic ecological processes. Water mixing dynamics at stream confluences influence physio-chemical characteristics of the stream as well as sediment mobilisation and pollutant dispersal. In this study, we investigated the potential for handheld

Gps monitoring of the la valette landslide (french alps) with two mono-frequency receivers

Science.gov (United States)

Squarzoni, C.; Delacourt, C.; Allemand, P.

2003-04-01

In the last years, the Global Positioning System techniques have been more and more employed in landslide monitoring. Here we present an application of the GPS techniques on the La Valette landslide, located in the Ubaye Valley in the southern French Alps. This complex landslide is composed by an upper part affected essentially by rotational mechanism, a central part with a generally translational movement and a lower part, occasionally transforming in mud flow in coincidence with strong rainfall events. Displacement rates are in average of a few centimetres per month and can reach one centimetre per day during spring. GPS data presented in this study have been acquired with a couple of mono-frequency GPS receivers Magellan ProMARK X-CM associated with multipath-resistant antennas and processed with the Magellan post-processing software MSTAR. Nine points have been set in the whole zone, seven of them in the moving area, one in a stable area near the landslide and one on the facing slope, used as reference point. For each measure, one GPS receiver is placed on the base point and the second one is placed on each monitored point for one-hour sessions. The baseline between base and monitored point ranges from 480 and 1660 m. Nine campaigns of measure have been made between October 2000 and October 2002, to follow the evolution of the surface displacements. The GPS results have been compared with the distance-meter measurements achieved on the same site by RTM Service (Restauration des Terrains de Montagne). The velocities obtained by the two methods are similar. The advantage of the GPS technique is the obtention of the real 3D displacement vector. These measurements have been combined with SAR interferometric data in order to derive a 3D map of the deformation.

Generalized Projective Synchronization between Two Complex Networks with Time-Varying Coupling Delay

International Nuclear Information System (INIS)

Mei, Sun; Chang-Yan, Zeng; Li-Xin, Tian

2009-01-01

Generalized projective synchronization (GPS) between two complex networks with time-varying coupling delay is investigated. Based on the Lyapunov stability theory, a nonlinear controller and adaptive updated laws are designed. Feasibility of the proposed scheme is proven in theory. Moreover, two numerical examples are presented, using the energy resource system and Lü's system [Physica A 382 (2007) 672] as the nodes of the networks. GPS between two energy resource complex networks with time-varying coupling delay is achieved. This study can widen the application range of the generalized synchronization methods and will be instructive for the demand–supply of energy resource in some regions of China

Generalized Projective Synchronization between Two Complex Networks with Time-Varying Coupling Delay

Science.gov (United States)

Sun, Mei; Zeng, Chang-Yan; Tian, Li-Xin

2009-01-01

Generalized projective synchronization (GPS) between two complex networks with time-varying coupling delay is investigated. Based on the Lyapunov stability theory, a nonlinear controller and adaptive updated laws are designed. Feasibility of the proposed scheme is proven in theory. Moreover, two numerical examples are presented, using the energy resource system and Lü's system [Physica A 382 (2007) 672] as the nodes of the networks. GPS between two energy resource complex networks with time-varying coupling delay is achieved. This study can widen the application range of the generalized synchronization methods and will be instructive for the demand-supply of energy resource in some regions of China.

The International GPS Service (IGS) as a Continuous Reference System for Precise GPS Positioning

Science.gov (United States)

Neilan, Ruth; Heflin, Michael; Watkins, Michael; Zumberge, James

1996-01-01

The International GPS Service for Geodynamics (IGS) is an organization which operates under the auspices of the International Association of Geodesy (IAG) and has been operational since January 1994. The primary objective of the IGS is to provide precise GPS data and data products to support geodetic and geophysical research activities.

Miniaturized GPS/MEMS IMU integrated board

Science.gov (United States)

Lin, Ching-Fang (Inventor)

2012-01-01

This invention documents the efforts on the research and development of a miniaturized GPS/MEMS IMU integrated navigation system. A miniaturized GPS/MEMS IMU integrated navigation system is presented; Laser Dynamic Range Imager (LDRI) based alignment algorithm for space applications is discussed. Two navigation cameras are also included to measure the range and range rate which can be integrated into the GPS/MEMS IMU system to enhance the navigation solution.

Accuracy of Handheld Blood Glucose Meters at High Altitude

NARCIS (Netherlands)

de Mol, Pieter; Krabbe, Hans G.; de Vries, Suzanna T.; Fokkert, Marion J.; Dikkeschei, Bert D.; Rienks, Rienk; Bilo, Karin M.; Bilo, Henk J. G.

2010-01-01

Background: Due to increasing numbers of people with diabetes taking part in extreme sports (e. g., high-altitude trekking), reliable handheld blood glucose meters (BGMs) are necessary. Accurate blood glucose measurement under extreme conditions is paramount for safe recreation at altitude. Prior

Hastighedskort for Danmark vha. GPS

DEFF Research Database (Denmark)

Andersen, Ove; Lahrmann, Harry; Torp, Kristian

2011-01-01

Hastighed på vejnettet er en central metrik indenfor trafikplanlægning og trafikoptimering. I denne artikel beskrives, hvorledes et hastighedskort for hele Danmark er skabt udelukkende vha. GPS data. To tilgangsvinkler til at beregne hastigheder vha. GPS data er præsenteret. Dette er hhv. en....... Opsummeret anses den turbaseret for at beregne det mest akkurate estimat, men metoden er meget datakrævende. Det er derfor nødvendigt at have den punktbaserede at falde tilbage på. Generelt mangler metoder til beregning af hastigheder vha. GPS data at blive valideret. Hvordan en sådan validering kan...

A handheld point-of-care genomic diagnostic system.

Directory of Open Access Journals (Sweden)

Frank B Myers

Full Text Available The rapid detection and identification of infectious disease pathogens is a critical need for healthcare in both developed and developing countries. As we gain more insight into the genomic basis of pathogen infectivity and drug resistance, point-of-care nucleic acid testing will likely become an important tool for global health. In this paper, we present an inexpensive, handheld, battery-powered instrument designed to enable pathogen genotyping in the developing world. Our Microfluidic Biomolecular Amplification Reader (µBAR represents the convergence of molecular biology, microfluidics, optics, and electronics technology. The µBAR is capable of carrying out isothermal nucleic acid amplification assays with real-time fluorescence readout at a fraction of the cost of conventional benchtop thermocyclers. Additionally, the µBAR features cell phone data connectivity and GPS sample geotagging which can enable epidemiological surveying and remote healthcare delivery. The µBAR controls assay temperature through an integrated resistive heater and monitors real-time fluorescence signals from 60 individual reaction chambers using LEDs and phototransistors. Assays are carried out on PDMS disposable microfluidic cartridges which require no external power for sample loading. We characterize the fluorescence detection limits, heater uniformity, and battery life of the instrument. As a proof-of-principle, we demonstrate the detection of the HIV-1 integrase gene with the µBAR using the Loop-Mediated Isothermal Amplification (LAMP assay. Although we focus on the detection of purified DNA here, LAMP has previously been demonstrated with a range of clinical samples, and our eventual goal is to develop a microfluidic device which includes on-chip sample preparation from raw samples. The µBAR is based entirely around open source hardware and software, and in the accompanying online supplement we present a full set of schematics, bill of materials, PCB layouts

A hand-held robotic device for peripheral intravenous catheterization.

Science.gov (United States)

Cheng, Zhuoqi; Davies, Brian L; Caldwell, Darwin G; Barresi, Giacinto; Xu, Qinqi; Mattos, Leonardo S

2017-12-01

Intravenous catheterization is frequently required for numerous medical treatments. However, this process is characterized by a high failure rate, especially when performed on difficult patients such as newborns and infants. Very young patients have small veins, and that increases the chances of accidentally puncturing the catheterization needle directly through them. In this article, we present the design, development and experimental evaluation of a novel hand-held robotic device for improving the process of peripheral intravenous catheterization by facilitating the needle insertion procedure. To our knowledge, this design is the first hand-held robotic device for assisting in the catheterization insertion task. Compared to the other available technologies, it has several unique advantages such as being compact, low-cost and able to reliably detect venipuncture. The system is equipped with an electrical impedance sensor at the tip of the catheterization needle, which provides real-time measurements used to supervise and control the catheter insertion process. This allows the robotic system to precisely position the needle within the lumen of the target vein, leading to enhanced catheterization success rate. Experiments conducted to evaluate the device demonstrated that it is also effective to deskill the task. Naïve subjects achieved an average catheterization success rate of 88% on a 1.5 mm phantom vessel with the robotic device versus 12% with the traditional unassisted system. The results of this work prove the feasibility of a hand-held assistive robotic device for intravenous catheterization and show that such device has the potential to greatly improve the success rate of these difficult operations.

Neurosurgery contact handheld probe based on sapphire shaped crystal

Science.gov (United States)

Shikunova, I. A.; Stryukov, D. O.; Rossolenko, S. N.; Kiselev, A. M.; Kurlov, V. N.

2017-01-01

A handheld contact probe based on sapphire shaped crystal is developed for intraoperative spectrally-resolved optical diagnostics, laser coagulation and aspiration of malignant brain tissue. The technology was integrated into the neurosurgical workflow for intraoperative real-time identification and removing of invasive brain cancer.

A handheld support system to facilitate stereological measurements and mapping of branching structures

DEFF Research Database (Denmark)

Gardi, J.E.; Wulfsohn, Dvora-Laiô; Nyengaard, J.R.

2007-01-01

specifications, software and Graphical User Interface (GUI) development, functionality and application of the handheld system using four examples: (1) sampling monkey lung bronchioles for estimation of diameter and wall thickness (2) sampling rat kidney for estimating number of arteries and arterioles......‘BranchSampler' is a system for computer-assisted manual stereology written for handheld devices running Windows CE. The system has been designed specifically to streamline data collection and optimize sampling of tree-like branching structures, with particular aims of reducing user errors, saving...

Sensing human activity : GPS tracking

NARCIS (Netherlands)

van der Spek, Stefan; van Schaick, Jeroen; de Bois, P.G.; de Haan, Remco

2009-01-01

The enhancement of GPS technology enables the use of GPS devices not only as navigation and orientation tools, but also as instruments used to capture travelled routes: as sensors that measure activity on a city scale or the regional scale. TU Delft developed a process and database architecture for

Imaging Emission Spectra with Handheld and Cellphone Cameras

Science.gov (United States)

Sitar, David

2012-01-01

As point-and-shoot digital camera technology advances it is becoming easier to image spectra in a laboratory setting on a shoestring budget and get immediate results. With this in mind, I wanted to test three cameras to see how their results would differ. Two undergraduate physics students and I used one handheld 7.1 megapixel (MP) digital Cannon…

GPS User Devices Parameter Control Methods

OpenAIRE

Klūga, A; Kuļikovs, M; Beļinska, V; Zeļenkovs, A

2007-01-01

In our day’s wide assortment of GPS user devices is manufacture. How to verify that parameters of the real device corresponds to parameters that manufacture shows. How to verify that parameters have not been changed during the operation time. The last one is very important for aviation GPS systems, which must be verified before the flight, but the values of parameter in time of repair works. This work analyses GPS user devices parameters control methods.

An Investigation of GeoBase Mission Data Set Design, Implementation, and Usage Within Air Force Civil Engineer Electrical and Utilities Work Centers

Science.gov (United States)

2005-03-01

described are ethnography , grounded theory, phenomenological, case study, and content analysis. As ethnography is based upon a longitudinal study in...handheld Global Positioning System (GPS) and data collection unit) and the Trimble Pathfinder Pro XRS® (a backpack mounted GPS and data collection...GIS office for updates. In the second process, the GIS office personnel used a GPS unit such as the Trimble Pathfinder Pro XRS® backpack mounted

Estimation of interplate coupling along Nankai trough considering the block motion model based on onland GNSS and seafloor GPS/A observation data using MCMC method

Science.gov (United States)

Kimura, H.; Ito, T.; Tadokoro, K.

2017-12-01

Introduction In southwest Japan, Philippine sea plate is subducting under the overriding plate such as Amurian plate, and mega interplate earthquakes has occurred at about 100 years interval. There is no occurrence of mega interplate earthquakes in southwest Japan, although it has passed about 70 years since the last mega interplate earthquakes: 1944 and 1946 along Nankai trough, meaning that the strain has been accumulated at plate interface. Therefore, it is essential to reveal the interplate coupling more precisely for predicting or understanding the mechanism of next occurring mega interplate earthquake. Recently, seafloor geodetic observation revealed the detailed interplate coupling distribution in expected source region of Nankai trough earthquake (e.g., Yokota et al. [2016]). In this study, we estimated interplate coupling in southwest Japan, considering block motion model and using seafloor geodetic observation data as well as onland GNSS observation data, based on Markov Chain Monte Carlo (MCMC) method. Method Observed crustal deformation is assumed that sum of rigid block motion and elastic deformation due to coupling at block boundaries. We modeled this relationship as a non-linear inverse problem that the unknown parameters are Euler pole of each block and coupling at each subfault, and solved them simultaneously based on MCMC method. Input data we used in this study are 863 onland GNSS observation data and 24 seafloor GPS/A observation data. We made some block division models based on the map of active fault tracing and selected the best model based on Akaike's Information Criterion (AIC): that is consist of 12 blocks. Result We find that the interplate coupling along Nankai trough has heterogeneous spatial distribution, strong at the depth of 0 to 20km at off Tokai region, and 0 to 30km at off Shikoku region. Moreover, we find that observed crustal deformation at off Tokai region is well explained by elastic deformation due to subducting Izu Micro

A GPS-Based Pitot-Static Calibration Method Using Global Output-Error Optimization

Science.gov (United States)

Foster, John V.; Cunningham, Kevin

2010-01-01

Pressure-based airspeed and altitude measurements for aircraft typically require calibration of the installed system to account for pressure sensing errors such as those due to local flow field effects. In some cases, calibration is used to meet requirements such as those specified in Federal Aviation Regulation Part 25. Several methods are used for in-flight pitot-static calibration including tower fly-by, pacer aircraft, and trailing cone methods. In the 1990 s, the introduction of satellite-based positioning systems to the civilian market enabled new inflight calibration methods based on accurate ground speed measurements provided by Global Positioning Systems (GPS). Use of GPS for airspeed calibration has many advantages such as accuracy, ease of portability (e.g. hand-held) and the flexibility of operating in airspace without the limitations of test range boundaries or ground telemetry support. The current research was motivated by the need for a rapid and statistically accurate method for in-flight calibration of pitot-static systems for remotely piloted, dynamically-scaled research aircraft. Current calibration methods were deemed not practical for this application because of confined test range size and limited flight time available for each sortie. A method was developed that uses high data rate measurements of static and total pressure, and GPSbased ground speed measurements to compute the pressure errors over a range of airspeed. The novel application of this approach is the use of system identification methods that rapidly compute optimal pressure error models with defined confidence intervals in nearreal time. This method has been demonstrated in flight tests and has shown 2- bounds of approximately 0.2 kts with an order of magnitude reduction in test time over other methods. As part of this experiment, a unique database of wind measurements was acquired concurrently with the flight experiments, for the purpose of experimental validation of the

Diagnostic efficacy of handheld devices for emergency radiologic consultation.

LENUS (Irish Health Repository)

Toomey, Rachel J

2010-02-01

Orthopedic injury and intracranial hemorrhage are commonly encountered in emergency radiology, and accurate and timely diagnosis is important. The purpose of this study was to determine whether the diagnostic accuracy of handheld computing devices is comparable to that of monitors that might be used in emergency teleconsultation.

Octopus: embracing the energy efficiency of handheld multimedia computers

NARCIS (Netherlands)

Havinga, Paul J.M.; Smit, Gerardus Johannes Maria

1999-01-01

In the MOBY DICK project we develop and define the architecture of a new generation of mobile hand-held computers called Mobile Digital Companions. The Companions must meet several major requirements: high performance, energy efficient, a notion of Quality of Service (QoS), small size, and low

Using GPS-surveyed intertidal zones to determine the validity of shorelines automatically mapped by Landsat water indices

Science.gov (United States)

Kelly, Joshua T.; Gontz, Allen M.

2018-03-01

Satellite remote sensing has been used extensively in a variety of shoreline studies and validated using aerial photography. This ground truth method only represents an instantaneous depiction of the shoreline at the time of acquisition and does not take into account the spatial and temporal variability of the dynamic shoreline boundary. Landsat 8‧s Operational Land Imager sensor's capability to accurately delineate a shoreline is assessed by comparing all known Landsat water index-derived shorelines with two GPS-surveyed intertidal zones that coincide with the satellite flyover date, one of which had near-neap tide conditions. Seven indices developed for automatically classifying water pixels were evaluated for their ability to delineate shorelines. The shoreline is described here as the area above and below maximum low and high tide, otherwise known as the intertidal zone. The high-water line, or wet/dry sediment line, was chosen as the shoreline indicator to be mapped using a handheld GPS. The proportion of the Landsat-derived shorelines that fell within this zone and their alongshore profile lengths were calculated. The most frequently used water index and the predecessor to Modified Normalized Difference Water Index (MNDWI), Normalized Difference Water Index (NDWI), was found to be the least accurate by a significant margin. Other indices required calibration of their threshold value to achieve accurate results, thus diminishing their replicability success for other regions. MNDWI was determined to be the best index for automated shoreline mapping, based on its superior accuracy and repeatable, stable threshold value.

Multiscale GPS tomography during COPS: validation and applications

Science.gov (United States)

Champollion, Cédric; Flamant, Cyrille; Masson, Frédéric; Gégout, Pascal; Boniface, Karen; Richard, Evelyne

2010-05-01

Accurate 3D description of the water vapour field is of interest for process studies such as convection initiation. None of the current techniques (LIDAR, satellite, radio soundings, GPS) can provide an all weather continuous 3D field of moisture. The combination of GPS tomography with radio-soundings (and/or LIDAR) has been used for such process studies using both advantages of vertically resolved soundings and high temporal density of GPS measurements. GPS tomography has been used at short scale (10 km horizontal resolution but in a 50 km² area) for process studies such as the ESCOMPTE experiment (Bastin et al., 2005) and at larger scale (50 km horizontal resolution) during IHOP_2002. But no extensive statistical validation has been done so far. The overarching goal of the COPS field experiment is to advance the quality of forecasts of orographically induced convective precipitation by four-dimensional observations and modeling of its life cycle for identifying the physical and chemical processes responsible for deficiencies in QPF over low-mountain regions. During the COPS field experiment, a GPS network of about 100 GPS stations has been continuously operating during three months in an area of 500 km² in the East of France (Vosges Mountains) and West of Germany (Black Forest). If the mean spacing between the GPS is about 50 km, an East-West GPS profile with a density of about 10 km is dedicated to high resolution tomography. One major goal of the GPS COPS experiment is to validate the GPS tomography with different spatial resolutions. Validation is based on additional radio-soundings and airborne / ground-based LIDAR measurement. The number and the high quality of vertically resolved water vapor observations give an unique data set for GPS tomography validation. Numerous tests have been done on real data to show the type water vapor structures that can be imaging by GPS tomography depending of the assimilation of additional data (radio soundings), the

Application of handheld devices to field research among underserved construction worker populations: a workplace health assessment pilot study

Directory of Open Access Journals (Sweden)

Fleming Lora E

2011-04-01

Full Text Available Abstract Background Novel low-cost approaches for conducting rapid health assessments and health promotion interventions among underserved worker groups are needed. Recruitment and participation of construction workers is particularly challenging due to their often transient periods of work at any one construction site, and their limited time during work to participate in such studies. In the present methodology report, we discuss the experience, advantages and disadvantages of using touch screen handheld devices for the collection of field data from a largely underserved worker population. Methods In March 2010, a workplace-centered pilot study to examine the feasibility of using a handheld personal device for the rapid health assessment of construction workers in two South Florida Construction sites was undertaken. A 45-item survey instrument, including health-related questions on tobacco exposure, workplace safety practices, musculoskeletal disorders and health symptoms, was programmed onto Apple iPod Touch® devices. Language sensitive (English and Spanish recruitment scripts, verbal consent forms, and survey questions were all preloaded onto the handheld devices. The experience (time to survey administration and capital cost of the handheld administration method was recorded and compared to approaches available in the extant literature. Results Construction workers were very receptive to the recruitment, interview and assessment processes conducted through the handheld devices. Some workers even welcomed the opportunity to complete the questionnaire themselves using the touch screen handheld device. A list of advantages and disadvantages emerged from this experience that may be useful in the rapid health assessment of underserved populations working in a variety of environmental and occupational health settings. Conclusions Handheld devices, which are relatively inexpensive, minimize survey response error, and allow for easy storage of data

Application of handheld devices to field research among underserved construction worker populations: a workplace health assessment pilot study.

Science.gov (United States)

Caban-Martinez, Alberto J; Clarke, Tainya C; Davila, Evelyn P; Fleming, Lora E; Lee, David J

2011-04-01

Novel low-cost approaches for conducting rapid health assessments and health promotion interventions among underserved worker groups are needed. Recruitment and participation of construction workers is particularly challenging due to their often transient periods of work at any one construction site, and their limited time during work to participate in such studies. In the present methodology report, we discuss the experience, advantages and disadvantages of using touch screen handheld devices for the collection of field data from a largely underserved worker population. In March 2010, a workplace-centered pilot study to examine the feasibility of using a handheld personal device for the rapid health assessment of construction workers in two South Florida Construction sites was undertaken. A 45-item survey instrument, including health-related questions on tobacco exposure, workplace safety practices, musculoskeletal disorders and health symptoms, was programmed onto Apple iPod Touch® devices. Language sensitive (English and Spanish) recruitment scripts, verbal consent forms, and survey questions were all preloaded onto the handheld devices. The experience (time to survey administration and capital cost) of the handheld administration method was recorded and compared to approaches available in the extant literature. Construction workers were very receptive to the recruitment, interview and assessment processes conducted through the handheld devices. Some workers even welcomed the opportunity to complete the questionnaire themselves using the touch screen handheld device. A list of advantages and disadvantages emerged from this experience that may be useful in the rapid health assessment of underserved populations working in a variety of environmental and occupational health settings. Handheld devices, which are relatively inexpensive, minimize survey response error, and allow for easy storage of data. These technological research modalities are useful in the

Performance of a new hand-held device for exhaled nitric oxide measurement in adults and children

Directory of Open Access Journals (Sweden)

Janson C

2006-04-01

Full Text Available Abstract Background Exhaled nitric oxide (NO measurement has been shown to be a valuable tool in the management of patients with asthma. Up to now, most measurements have been done with stationary, chemiluminescence-based NO analysers, which are not suitable for the primary health care setting. A hand-held NO analyser which simplifies the measurement would be of value both in specialized and primary health care. In this study, the performance of a new electrochemical hand-held device for exhaled NO measurements (NIOX MINO was compared with a standard stationary chemiluminescence unit (NIOX. Methods A total of 71 subjects (6–60 years; 36 males, both healthy controls and atopic patients with and without asthma were included. The mean of three approved exhalations (50 ml/s in each device, and the first approved measurement in the hand-held device, were compared with regard to NO readings (Bland-Altman plots, measurement feasibility (success rate with 6 attempts and repeatability (intrasubject SD. Results Success rate was high (≥ 84% in both devices for both adults and children. The subjects represented a FENO range of 8–147 parts per billion (ppb. When comparing the mean of three measurements (n = 61, the median of the intrasubject difference in exhaled NO for the two devices was -1.2 ppb; thus generally the hand-held device gave slightly higher readings. The Bland-Altman plot shows that the 95% limits of agreement were -9.8 and 8.0 ppb. The intrasubject median difference between the NIOX and the first approved measurement in the NIOX MINO was -2.0 ppb, and limits of agreement were -13.2 and 10.2 ppb. The median repeatability for NIOX and NIOX MINO were 1.1 and 1.2 ppb, respectively. Conclusion The hand-held device (NIOX MINO and the stationary system (NIOX are in clinically acceptable agreement both when the mean of three measurements and the first approved measurement (NIOX MINO is used. The hand-held device shows good repeatability, and it

Performance of a new hand-held device for exhaled nitric oxide measurement in adults and children.

Science.gov (United States)

Alving, K; Janson, C; Nordvall, L

2006-04-20

Exhaled nitric oxide (NO) measurement has been shown to be a valuable tool in the management of patients with asthma. Up to now, most measurements have been done with stationary, chemiluminescence-based NO analysers, which are not suitable for the primary health care setting. A hand-held NO analyser which simplifies the measurement would be of value both in specialized and primary health care. In this study, the performance of a new electrochemical hand-held device for exhaled NO measurements (NIOX MINO) was compared with a standard stationary chemiluminescence unit (NIOX). A total of 71 subjects (6-60 years; 36 males), both healthy controls and atopic patients with and without asthma were included. The mean of three approved exhalations (50 ml/s) in each device, and the first approved measurement in the hand-held device, were compared with regard to NO readings (Bland-Altman plots), measurement feasibility (success rate with 6 attempts) and repeatability (intrasubject SD). Success rate was high (> or = 84%) in both devices for both adults and children. The subjects represented a FENO range of 8-147 parts per billion (ppb). When comparing the mean of three measurements (n = 61), the median of the intrasubject difference in exhaled NO for the two devices was -1.2 ppb; thus generally the hand-held device gave slightly higher readings. The Bland-Altman plot shows that the 95% limits of agreement were -9.8 and 8.0 ppb. The intrasubject median difference between the NIOX and the first approved measurement in the NIOX MINO was -2.0 ppb, and limits of agreement were -13.2 and 10.2 ppb. The median repeatability for NIOX and NIOX MINO were 1.1 and 1.2 ppb, respectively. The hand-held device (NIOX MINO) and the stationary system (NIOX) are in clinically acceptable agreement both when the mean of three measurements and the first approved measurement (NIOX MINO) is used. The hand-held device shows good repeatability, and it can be used successfully on adults and most children

Neurosurgical hand-held optical coherence tomography (OCT) forward-viewing probe

Science.gov (United States)

Sun, Cuiru; Lee, Kenneth K. C.; Vuong, Barry; Cusimano, Michael; Brukson, Alexander; Mariampillai, Adrian; Standish, Beau A.; Yang, Victor X. D.

2012-02-01

A prototype neurosurgical hand-held optical coherence tomography (OCT) imaging probe has been developed to provide micron resolution cross-sectional images of subsurface tissue during open surgery. This new ergonomic hand-held probe has been designed based on our group's previous work on electrostatically driven optical fibers. It has been packaged into a catheter probe in the familiar form factor of the clinically accepted Bayonet shaped neurosurgical non-imaging Doppler ultrasound probes. The optical design was optimized using ZEMAX simulation. Optical properties of the probe were tested to yield an ~20 um spot size, 5 mm working distance and a 3.5 mm field of view. The scan frequency can be increased or decreased by changing the applied voltage. Typically a scan frequency of less than 60Hz is chosen to keep the applied voltage to less than 2000V. The axial resolution of the probe was ~15 um (in air) as determined by the OCT system. A custom-triggering methodology has been developed to provide continuous stable imaging, which is crucial for clinical utility. Feasibility of this probe, in combination with a 1310 nm swept source OCT system was tested and images are presented to highlight the usefulness of such a forward viewing handheld OCT imaging probe. Knowledge gained from this research will lay the foundation for developing new OCT technologies for endovascular management of cerebral aneurysms and transsphenoidal neuroendoscopic treatment of pituitary tumors.

Constraints on dike propagation from continuous GPS measurements

Science.gov (United States)

Segall, P.; Cervelli, Peter; Owen, S.; Lisowski, M.; Miklius, Asta

2001-01-01

The January 1997 East Rift Zone eruption on Kilauea volcano, Hawaii, occurred within a network of continuous Global Positioning System (GPS) receivers. The GPS measurements reveal the temporal history of deformation during dike intrusion, beginning ??? 8 hours prior to the onset of the eruption. The dike volume as a function of time, estimated from the GPS data using elastic Green's functions for a homogeneous half-space, shows that only two thirds of the final dike volume accumulated prior to the eruption and the rate of volume change decreased with time. These observations are inconsistent with simple models of dike propagation, which predict accelerating dike volume up to the time of the eruption and little or no change thereafter. Deflationary tilt changes at Kilauea summit mirror the inferred dike volume history, suggesting that the rate of dike propagation is limited by flow of magma into the dike. A simple, lumped parameter model of a coupled dike magma chamber system shows that the tendency for a dike to end in an eruption (rather than intrusion) is favored by high initial dike pressures, compressional stress states, large, compressible magma reservoirs, and highly conductive conduits linking the dike and source reservoirs. Comparison of model predictions to the observed dike volume history, the ratio of erupted to intruded magma, and the deflationary history of the summit magma chamber suggest that most of the magma supplied to the growing dike came from sources near to the eruption through highly conductive conduits. Interpretation is complicated by the presence of multiple source reservoirs, magma vesiculation and cooling, as well as spatial variations in dike-normal stress. Reinflation of the summit magma chamber following the eruption was measured by GPS and accompanied a rise in the level of the Pu'u O'o lava lake. For a spheroidal chamber these data imply a summit magma chamber volume of ??? 20 km3, consistent with recent estimates from seismic

Utilizing Glove-Based Gestures and a Tactile Vest Display for Covert Communications and Robot Control

Science.gov (United States)

2014-06-01

wearing instrumented glove for hand and arm signals. .......................................9 Figure 4. TDS Nomad handheld computer...of a standard tactical glove with accelerometers embedded within each finger, and an accelerometer, gyroscope, and digital compass embedded in the...signal communication were performed by two TDS Nomad GPS-enabled ruggedized handheld computers (one carried by the individual generating hand signals and

Interactive topology optimization on hand-held devices

DEFF Research Database (Denmark)

Aage, Niels; Nobel-Jørgensen, Morten; Andreasen, Casper Schousboe

2013-01-01

This paper presents an interactive topology optimization application designed for hand-held devices running iOS or Android. The TopOpt app solves the 2D minimum compliance problem with interactive control of load and support positions as well as volume fraction. Thus, it is possible to change......OS devices from the Apple App Store, at Google Play for the Android platform, and a web-version can be run from www.topopt.dtu.dk....

Briefing highlights space weather risks to GPS

Science.gov (United States)

Tretkoff, Ernie

2011-07-01

Solar storms, which are expected to increase as the Sun nears the most active phase of the solar cycle, can disrupt a variety of technologies on which society relies. Speakers at a 22 June briefing on Capitol Hill in Washington, D. C., focused on how space weather can affect the Global Positioning System (GPS), which is used in a wide range of industries, including commercial air travel, agriculture, national security, and emergency response. Rocky Stone, chief technical pilot for United Airlines, noted that GPS allows more aircraft to be in airspace, saves fuel, and helps aircraft move safely on runways. “Improvements in space weather forecasting need to be pursued,” he said. Precision GPS has also “changed the whole nature of farming,” said Ron Hatch, Director of Navigation Systems, NavCom Technology/John Deere. GPS makes it possible for tractors to be driven in the most efficient paths and for fertilizer and water to be applied precisely to the areas that most need them. Space weather-induced degradation of GPS signals can cause significant loss to farms that rely on GPS. Elizabeth Zimmerman, Deputy Associate Administrator for the Office of Response and Recovery at the Federal Emergency Management Agency (FEMA), described how FEMA relies on GPS for disaster recovery. The agency is developing an operations plan for dealing with space weather, she said.

Development of GPS survey data management protocols/policy.

Science.gov (United States)

2010-08-01

This project developed a statewide policy and criteria for collecting, analyzing, and managing global position system (GPS) survey data. The research project determined the needs of the Department in adopting the GPS real time kinetic (GPS RTK) stake...

GPS Usage in a Population of Low-Vision Drivers.

Science.gov (United States)

Cucuras, Maria; Chun, Robert; Lee, Patrick; Jay, Walter M; Pusateri, Gregg

2017-01-01

We surveyed bioptic and non-bioptic low-vision drivers in Illinois, USA, to determine their usage of global positioning system (GPS) devices. Low-vision patients completed an IRB-approved phone survey regarding driving demographics and usage of GPS while driving. Participants were required to be active drivers with an Illinois driver's license, and met one of the following criteria: best-corrected visual acuity (BCVA) less than or equal to 20/40, central or significant peripheral visual field defects, or a combination of both. Of 27 low-vision drivers, 10 (37%) used GPS while driving. The average age for GPS users was 54.3 and for non-users was 77.6. All 10 drivers who used GPS while driving reported increased comfort or safety level. Since non-GPS users were significantly older than GPS users, it is likely that older participants would benefit from GPS technology training from their low-vision eye care professionals.

Hand-held and automated breast ultrasound

International Nuclear Information System (INIS)

Bassett, L.W.; Gold, R.H.; Kimme-Smith, C.

1985-01-01

The book is a guide for physicians and technologists who use US as an adjunct to mammography; it carefully outlines the pros and cons of US of the breast and its role in the diagnosis of benign and malignant diseases. After an introduction that discusses the philosophy of breast US, the chapters cover the physics of US and instrumentation (both hand-held transducers as well as automated water path scanners), then proceed to a discussion of the normal breast. Sections on benign disorders, malignant lesions, and pitfalls of diagnosis are followed by quiz cases

Transportation mode recognition using GPS and accelerometer data

NARCIS (Netherlands)

Feng, T.; Timmermans, H.J.P.

2013-01-01

Potential advantages of global positioning systems (GPS) in collecting travel behavior data have been discussed in several publications and evidenced in many recent studies. Most applications depend on GPS information only. However, transportation mode detection that relies only on GPS information

Gestió mapes i GPS

OpenAIRE

Díaz Sañudo, Daniel

2013-01-01

El projecte denominat "Gestor de mapes i GPS" és una aplicació per a dispositius mòbils Android que utilitza l'API v.1 de Google Maps. El proyecto denominado "Gestor de mapas y GPS" es una aplicación para dispositivos móviles Android que utiliza la API v.1 de Google Maps.

Location - Global Positioning System (GPS) Photos

Data.gov (United States)

Army Corps of Engineers, Department of the Army, Department of Defense — Digital photos tagged with GPS location information. The St. Paul District maintains a digital library of over 10,000 GPS photos. Photos are often associated with...

GPS Operations at Olkiluoto, Kivetty and Romuvaara in 2005

International Nuclear Information System (INIS)

Ahola, J.; Ollikainen, M.; Koivula, H.; Jokela, J.

2006-07-01

The GPS based deformation studies has been made at the investigation areas of Posiva since 1995, when the network of ten GPS pillars was established at Olkiluoto. The network of seven GPS pillars was built at Kivetty and Romuvaara during the year 1996. One pillar in each investigation area belongs to the Finnish permanent GPS network, FinnRef. Twenty GPS measurement campaigns have been carried out at Olkiluoto since 1995, and fourteen campaigns at Kivetty and Romuvaara. According to the time series of the GPS results 1/3 of the baselines at Olkiluoto have statistically significant change rates. However, the observed movements are smaller than ± 0.22 mm/a. There are no statistically signicant movements at Kivetty and Romuvaara expect one pillar at Romuvaara. There are five pillars, which have statistically significant horizontal velocities at Olkiluoto. The local velocity components are small but taking into account the standard deviations the largest velocity components seems to be reliable (maximum velocity is - 0.25 mm/a ± 0.025 mm/a). The uniform scale for the GPS measurements made in different years is the basic condition for reliable results in the deformation analyses. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured using EDM instruments simultaneously with the GPS observations. The comparison between the GPS and EDM results to show a possible scale error of the GPS. The GPS network at Olkiluoto was enlarged in 2003. The new pillars were built close to Kuivalahti village and on a small island of Iso Pyrekari, both north from Olkiluoto. According to the geological evidence it is expected that a fracture zone is located between the new stations, thus enabling the determination of possible deformations along the fracture zone. The new pillars have been observed five times since 2003, but the time series are still too short for reliable deformation studies. Including the new pillars the local

Comparison of GLONASS and GPS Time Transfers

Science.gov (United States)

Daly, P.; Koshelyaevsky, N. B.; Lewandowski, W.; Petit, G.; Thomas, C.

1993-01-01

The Russian global space navigation system GLONASS could provide a technique similar to GPS for international time comparison. The main limitation to its use for time transfer is the lack of commercially available time receivers. The University of Leeds built a GPS/GLONASS receiver five years ago and since then has provided continuous information about GLONASS time and its comparison with GPS time. For the last two years the VNIIFTRI and several other Russian time laboratories have used Russian-built GLONASS navigation receivers for time comparisons. Since June 1991, the VNIIFTRI has operated a GPS time receiver which offers, for the first time, an opportunity for the direct comparison of time transfers using GPS and GLONASS. This seven-month experiment shows that even with relatively imprecise data recording and processing, in terms of time metrology, GLONASS can provide continental time transfer at a level of several tens of nanoseconds.

Technology-enabled division of labour: the use of handhelds

NARCIS (Netherlands)

Benders, J.G.J.M.; Schouteten, R.L.J.; Ruijsscher, C. de

2012-01-01

Using the task pool model and data from 15 establishments in the Dutch hospitality industry, this study shows how and why applying handhelds affects the division of labour. These devices allow to split the waiters' jobs into separate tasks which tend to be combined into two separate "sub jobs": the

Technology-enabled division of labour : The use of handhelds

NARCIS (Netherlands)

Benders, J.G.J.M.; Schouteten, R.; de Ruijsscher, C.

2012-01-01

Using the task pool model and data from 15 establishments in the Dutch hospitality industry, this study shows how and why applying handhelds affects the division of labour. These devices allow to split the waiters' jobs into separate tasks which tend to be combined into two separate "sub jobs": the

Development of radiation monitoring and visualization systems for Fukushima. GPS monitoring system, Dose3DMap system, and LED-coupled scintillating fiber detector

International Nuclear Information System (INIS)

Nakao, Noriaki; Kosako, Kazuaki; Kinoshita, Norikazu; Kawaguchi, Masato

2016-01-01

Lands that were contaminated with radioactive elements following the Fukushima Daiichi Nuclear Power Plant accident in 2011 have been decontaminated, and the construction of an interim storage facility for radioactive waste is planned. A GPS monitoring system was developed to concomitantly determine a location and measure the radiation level at the location. Moreover, a mapping system that produces radiation maps at the measurement locations and also predicts post-decontamination radiation maps using the compiled Monte Carlo simulation program was constructed. These systems were used for decontamination planning and estimation of the decontamination effect. An LED-coupled scintillating fiber detector was developed for visually monitoring radiation in real time at the interim storage facility. The LEDs display different colors corresponding to different radiation levels at the measurement locations along the fiber detector, the maximum length of which is 50 m. Thus, the radiation levels at all positions along the length of the detector can be visually monitored in real time. Moreover, it is useful for radiation safety and for risk communication with radiation workers and residents close to the site. (author)

GPS operations at Olkiluoto, Kivetty and Romuvaara in 2010

International Nuclear Information System (INIS)

Kallio, U.; Nyberg, S.; Koivula, H.; Jokela, J.; Poutanen, M.

2011-11-01

The Finnish Geodetic Institute (FGI) has studied crustal deformations in co-operation with the Posiva Oy since 1994, when a network of ten pillars for GPS observations was established at Olkiluoto. In 2010 the local GPS network at Olkiluoto consisted of 14 concrete pillars. The whole network has been measured twice a year in the static GPS campaigns with 24 h sessions. The four new pillars were established in 2010 and the permanent measurements on them will start in 2011. The network of seven GPS pillars was built at Kivetty and Romuvaara during the year 1996. One pillar in each investigation area belongs to the Finnish permanent GPS network, FinnRef. A total of 28 GPS measurement campaigns have been carried out at Olkiluoto since 1995, and 18 campaigns at Kivetty and Romuvaara. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured in connection to the GPS observations using the EDM instrument Kern ME5000 Mekometer. The GPS operations in 2010 included the two GPS campaigns at Olkiluoto, GPS campaigns at Kivetty and Romuvaara, EDM baseline measurements at Olkiluoto, and the control marker measurements with the tachymeter at Olkiluoto. All GPS data history was reprocessed with Bernese GPS software using the new processing strategy tested in 2009. The results were analysed by computing the change rates of the baselines and estimating horizontal velocities for the pillars using the barycenter of the velocities as a reference. In the Olkiluoto inner network 80 percent of the change rates were smaller than 0.10 mm/a. Roughly one fourth of the change rates could be considered as statistically significant (change rate larger than 3 σ. The statistically significant change rates were mainly related to the Olkiluoto permanent station (GPS1) and to the pillar GPS5, which had also the maximum change rate (0.21 ± 0.03 mm/a). In Olkiluoto outer network the maximum and statistically significant change rates are

GPS operations at Olkiluoto, Kivetty and Romuvaara in 2010

Energy Technology Data Exchange (ETDEWEB)

Kallio, U.; Nyberg, S.; Koivula, H.; Jokela, J.; Poutanen, M. [Finnish Geodetic Institute, Masala (Finland)

2011-11-15

The Finnish Geodetic Institute (FGI) has studied crustal deformations in co-operation with the Posiva Oy since 1994, when a network of ten pillars for GPS observations was established at Olkiluoto. In 2010 the local GPS network at Olkiluoto consisted of 14 concrete pillars. The whole network has been measured twice a year in the static GPS campaigns with 24 h sessions. The four new pillars were established in 2010 and the permanent measurements on them will start in 2011. The network of seven GPS pillars was built at Kivetty and Romuvaara during the year 1996. One pillar in each investigation area belongs to the Finnish permanent GPS network, FinnRef. A total of 28 GPS measurement campaigns have been carried out at Olkiluoto since 1995, and 18 campaigns at Kivetty and Romuvaara. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured in connection to the GPS observations using the EDM instrument Kern ME5000 Mekometer. The GPS operations in 2010 included the two GPS campaigns at Olkiluoto, GPS campaigns at Kivetty and Romuvaara, EDM baseline measurements at Olkiluoto, and the control marker measurements with the tachymeter at Olkiluoto. All GPS data history was reprocessed with Bernese GPS software using the new processing strategy tested in 2009. The results were analysed by computing the change rates of the baselines and estimating horizontal velocities for the pillars using the barycenter of the velocities as a reference. In the Olkiluoto inner network 80 percent of the change rates were smaller than 0.10 mm/a. Roughly one fourth of the change rates could be considered as statistically significant (change rate larger than 3 {sigma}. The statistically significant change rates were mainly related to the Olkiluoto permanent station (GPS1) and to the pillar GPS5, which had also the maximum change rate (0.21 {+-} 0.03 mm/a). In Olkiluoto outer network the maximum and statistically significant change rates

The Mobile Surface Contamination Monitor II environmental radiological characterization utilizing GPS/GIS technologies

International Nuclear Information System (INIS)

Wendling, M.A.

1993-05-01

Time, cost, and most importantly quality of data are the three factors to measure the success of field radiological characterizations. The application of coupling radiation detection instrumentation to a GPS receiver has dramatically increased the data quality achievable compared to traditional environmental radiological survey methods. Improvements in verifying adequate spatial coverage of an area while collecting data and at,the same time reducing field time requirements can be realized. Data acquired during the recent implementation of the Mobile Surface Contamination Monitor 11 (MSCM-11) will be presented to demonstrate the advantages of this system over traditional radiological survey methods. The comparison will include time and manpower requirements. Linking the complimentary GPS, GIS and radiation detection technologies on a mobile tractor based platform has provided a tool to provide radiological characterization data faster, cheaper, and better to assist in the Environmental Restoration Mission of the Hanford Site

Continuing medical education and burnout among Danish GPs

DEFF Research Database (Denmark)

Brøndt, Anders; Sokolowski, Ineta; Olesen, Frede

2008-01-01

BACKGROUND: There has been minimal research into continuing medical education (CME) and its association with burnout among GPs. AIM: The aim of this study was to investigate the association between participating in CME and experiencing burnout in a sample of Danish GPs. DESIGN OF STUDY: Cross......-sectional questionnaire study. SETTING: All 458 active GPs in 2004, in the County of Aarhus, Denmark were invited to participate. METHOD: Data on CME activities were obtained for all GPs and linked to burnout which was measured using the Maslach Burnout Inventory - Human Services Survey. The relationship between CME...... activity and burnout was calculated as prevalence ratios (PR) in a generalised linear model. RESULTS: In total, 379 (83.5%) GPs returned the questionnaire. The prevalence of burnout was about 25%, and almost 3% suffered from 'high burnout'. A total of 344 (92.0%) GPs were members of a CME group...

Abdominoplasty and seroma: a prospective randomised study comparing scalpel and handheld electrocautery dissection.

Science.gov (United States)

Marsh, Dan J; Fox, Andreas; Grobbelaar, Adriaan O; Chana, Jagdeep S

2015-02-01

Seroma formation remains a significant problem in abdominoplasty procedures--the cause of which remains to be elucidated. It has been suggested that one of the causative factors for seroma formation is the use of handheld electrocautery as opposed to scalpel for abdominal flap dissection. Prospective trial in 102 consecutive abdominoplasty patients randomised to have abdominal flap dissection with either handheld electrocautery device on 'coagulation setting' or sharp dissection with scalpel and monopolar electrocautery forceps for haemostasis. In all other aspects the surgical technique was identical between the two groups. All drains were removed at 48 h, irrespective of drain volume. Primary outcome measure is postoperative seroma formation on clinical examination, secondary outcome measures are drain volume, weight of tissue removed, effect of liposuction and patient BMI. Both study groups were similar in demographics with no significant difference in weight of tissue excised, BMI, drain output or post operative complictions. There was no significant difference in seroma formation rates between the handheld electrocautery group (17.2%) and the sharp dissection group (20.1%). Overall, the seroma rate was 18.6%. Liposuction to the flanks at the time of abdominoplasty was found to significantly increase the incidence of seroma, compared to patients having abdominoplasty alone. Use of handheld electrocautery rather than scalpel for tissue dissection does not lead to increased seroma formation in abdominoplasty patients. Concomitant liposuction at the time of abdominoplasty increases the risk of seroma formation compared to patients having abdominoplasty alone. Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

GPS Tomography: Water Vapour Monitoring for Germany

Science.gov (United States)

Bender, Michael; Dick, Galina; Wickert, Jens; Raabe, Armin

2010-05-01

Ground based GPS atmosphere sounding provides numerous atmospheric quantities with a high temporal resolution for all weather conditions. The spatial resolution of the GPS observations is mainly given by the number of GNSS satellites and GPS ground stations. The latter could considerably be increased in the last few years leading to more reliable and better resolved GPS products. New techniques such as the GPS water vapour tomography gain increased significance as data from large and dense GPS networks become available. The GPS tomography has the potential to provide spatially resolved fields of different quantities operationally, i. e. the humidity or wet refractivity as required for meteorological applications or the refraction index which is important for several space based observations or for precise positioning. The number of German GPS stations operationally processed by the GFZ in Potsdam was recently enlarged to more than 300. About 28000 IWV observations and more than 1.4 millions of slant total delay data are now available per day with a temporal resolution of 15 min and 2.5 min, respectively. The extended network leads not only to a higher spatial resolution of the tomographically reconstructed 3D fields but also to a much higher stability of the inversion process and with that to an increased quality of the results. Under these improved conditions the GPS tomography can operate continuously over several days or weeks without applying too tight constraints. Time series of tomographically reconstructed humidity fields will be shown and different initialisation strategies will be discussed: Initialisation with a simple exponential profile, with a 3D humidity field extrapolated from synoptic observations and with the result of the preceeding reconstruction. The results are compared to tomographic reconstructions initialised with COSMO-DE analyses and to the corresponding model fields. The inversion can be further stabilised by making use of independent

A hand-held beta imaging probe for FDG.

Science.gov (United States)

Singh, Bipin; Stack, Brendan C; Thacker, Samta; Gaysinskiy, Valeriy; Bartel, Twyla; Lowe, Val; Cool, Steven; Entine, Gerald; Nagarkar, Vivek

2013-04-01

Advances in radiopharmaceuticals and clinical understanding have escalated the use of intraoperative gamma probes in surgery. However, most probes on the market are non-imaging gamma probes that suffer from the lack of ancillary information of the surveyed tissue area. We have developed a novel, hand-held digital Imaging Beta Probe™ (IBP™) to be used in surgery in conjunction with beta-emitting radiopharmaceuticals such as (18)FDG, (131)I and (32)P for real-time imaging of a surveyed area with higher spatial resolution and sensitivity and greater convenience than existing instruments. We describe the design and validation of a hand-held beta probe intended to be used as a visual mapping device to locate and confirm excision of (18)FDG-avid primary tumors and metastases in an animal model. We have demonstrated a device which can generate beta images from (18)FDG avid lesions in an animal model. It is feasible to image beta irradiation in animal models of cancer given (18)FDG. This technology may be applied to clinical mapping of tumors and/or their metastases in the operating room. Visual image depiction of malignancy may aid the surgeon in localization and excision of lesions of interest.

Contribution of various microenvironments to the daily personal exposure to ultrafine particles: Personal monitoring coupled with GPS tracking

Science.gov (United States)

Bekö, Gabriel; Kjeldsen, Birthe Uldahl; Olsen, Yulia; Schipperijn, Jasper; Wierzbicka, Aneta; Karottki, Dorina Gabriela; Toftum, Jørn; Loft, Steffen; Clausen, Geo

2015-06-01

Exposure to ultrafine particles (UFP) may have adverse health effects. Central monitoring stations do not represent the personal exposure to UFP accurately. Few studies have previously focused on personal exposure to UFP. Sixty non-smoking residents living in Copenhagen, Denmark were asked to carry a backpack equipped with a portable monitor, continuously recording particle number concentrations (PN), in order to measure the real-time individual exposure over a period of ˜48 h. A GPS logger was carried along with the particle monitor and allowed us to estimate the contribution of UFP exposure occurring in various microenvironments (residence, during active and passive transport, other indoor and outdoor environments) to the total daily exposure. On average, the fractional contribution of each microenvironment to the daily integrated personal exposure roughly corresponded to the fractions of the day the subjects spent in each microenvironment. The home environment accounted for 50% of the daily personal exposure. Indoor environments other than home or vehicles contributed with ˜40%. The highest median UFP concentration was obtained during passive transport (vehicles). However, being in transit or outdoors contributed 5% or less to the daily exposure. Additionally, the subjects recorded in a diary the periods when they were at home. With this approach, 66% of the total daily exposure was attributable to the home environment. The subjects spent 28% more time at home according to the diary, compared to the GPS. These results may indicate limitations of using diaries, but also possible inaccuracy and miss-classification in the GPS data.

GPS-based system for satellite tracking and geodesy

Science.gov (United States)

Bertiger, Willy I.; Thornton, Catherine L.

1989-01-01

High-performance receivers and data processing systems developed for GPS are reviewed. The GPS Inferred Positioning System (GIPSY) and the Orbiter Analysis and Simulation Software (OASIS) are described. The OASIS software is used to assess GPS system performance using GIPSY for data processing. Consideration is given to parameter estimation for multiday arcs, orbit repeatability, orbit prediction, daily baseline repeatability, agreement with VLBI, and ambiguity resolution. Also, the dual-frequency Rogue receiver, which can track up to eight GPS satellites simultaneously, is discussed.

GPS Test Facility

Data.gov (United States)

Federal Laboratory Consortium — The Global Positioning System (GPS) Test Facility Instrumentation Suite (GPSIS) provides great flexibility in testing receivers by providing operational control of...

Video Browsing on Handheld Devices

Science.gov (United States)

Hürst, Wolfgang

Recent improvements in processing power, storage space, and video codec development enable users now to playback video on their handheld devices in a reasonable quality. However, given the form factor restrictions of such a mobile device, screen size still remains a natural limit and - as the term "handheld" implies - always will be a critical resource. This is not only true for video but any data that is processed on such devices. For this reason, developers have come up with new and innovative ways to deal with large documents in such limited scenarios. For example, if you look at the iPhone, innovative techniques such as flicking have been introduced to skim large lists of text (e.g. hundreds of entries in your music collection). Automatically adapting the zoom level to, for example, the width of table cells when double tapping on the screen enables reasonable browsing of web pages that have originally been designed for large, desktop PC sized screens. A multi touch interface allows you to easily zoom in and out of large text documents and images using two fingers. In the next section, we will illustrate that advanced techniques to browse large video files have been developed in the past years, as well. However, if you look at state-of-the-art video players on mobile devices, normally just simple, VCR like controls are supported (at least at the time of this writing) that only allow users to just start, stop, and pause video playback. If supported at all, browsing and navigation functionality is often restricted to simple skipping of chapters via two single buttons for backward and forward navigation and a small and thus not very sensitive timeline slider.

Web-Based Spatial Training Using Handheld Touch Screen Devices

Science.gov (United States)

Martin-Dorta, Norena; Saorin, Jose Luis; Contero, Manuel

2011-01-01

This paper attempts to harness the opportunities for mobility and the new user interfaces that handheld touch screen devices offer, in a non-formal learning context, with a view to developing spatial ability. This research has addressed two objectives: first, analyzing the effects that training can have on spatial visualisation using the…

Multimodal ophthalmic imaging using handheld spectrally encoded coherence tomography and reflectometry (SECTR)

Science.gov (United States)

Leeburg, Kelsey C.; El-Haddad, Mohamed T.; Malone, Joseph D.; Terrones, Benjamin D.; Tao, Yuankai K.

2018-02-01

Scanning laser ophthalmoscopy (SLO) provides high-speed, noninvasive en face imaging of the retinal fundus. Optical coherence tomography (OCT) is the current "gold-standard" for ophthalmic diagnostic imaging and enables depth-resolved visualization of ophthalmic structures and image-based surrogate biomarkers of disease. We present a compact optical and mechanical design for handheld spectrally encoded coherence tomography and reflectometry (SECTR) for multimodality en face spectrally encoded reflectometry (SER) and cross-sectional OCT imaging. We custom-designed a double-pass telecentric scan lens, which halves the size of 4-f optical relays and allowed us to reduce the footprint of our SECTR scan-head by a factor of >2.7x (volume) over our previous design. The double-pass scan lens was optimized for diffraction-limited performance over a +/-10° scan field. SECTR optics and optomechanics were combined in a compact rapid-prototyped enclosure with dimensions 87 x 141.8 x 137 mm (w x h x d). SECTR was implemented using a custom-built 400 kHz 1050 nm swept-source. OCT and SER were simultaneously digitized on dual input channels of a 4 GS/s digitizer at 1.4 GS/s per channel. In vivo human en face SER and cross-sectional OCT images were acquired at 350 fps. OCT volumes of 1000 B-scans were acquired in 2.86 s. We believe clinical translation of our compact handheld design will benefit point-of-care ophthalmic diagnostics in patients who are unable to be imaged on conventional slit-lamp based systems, such as infants and the bedridden. When combined with multi-volumetric registration methods, handheld SECTR will have advantages in motion-artifact free imaging over existing handheld technologies.

An ultra-wide bandwidth-based range/GPS tight integration approach for relative positioning in vehicular ad hoc networks

International Nuclear Information System (INIS)

Shen, Feng; Cheong, Joon Wayn; Dempster, Andrew G

2015-01-01

Relative position awareness is a vital premise for the implementation of emerging intelligent transportation systems, such as collision warning. However, commercial global navigation satellite systems (GNSS) receivers do not satisfy the requirements of these applications. Fortunately, cooperative positioning (CP) techniques, through sharing the GNSS measurements between vehicles, can improve the performance of relative positioning in a vehicular ad hoc network (VANET). In this paper, while assuming there are no obstacles between vehicles, a new enhanced tightly coupled CP technique is presented by adding ultra-wide bandwidth (UWB)-based inter-vehicular range measurements. In the proposed CP method, each vehicle fuses the GPS measurements and the inter-vehicular range measurements. Based on analytical and experimental results, in the full GPS coverage environment, the new tight integration CP method outperforms the INS-aided tight CP method, tight CP method, and DGPS by 11%, 15%, and 24%, respectively; in the GPS outage scenario, the performance improvement achieves 60%, 65%, and 73%, respectively. (paper)

Contents of GPS Data Files

Energy Technology Data Exchange (ETDEWEB)

Sullivan, John P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carver, Matthew Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Norman, Benjamin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-12-09

There are no very detailed descriptions of most of these instruments in the literature – we will attempt to fix that problem in the future. The BDD instruments are described in [1]. One of the dosimeter instruments on CXD boxes is described in [2]. These documents (or web links to them) and a few others are in this directory tree. The cross calibration of the CXD electron data with RBSP is described in [3]. Each row in the data file contains the data from one time bin from a CXD or BDD instrument along with a variety of parameters derived from the data. Time steps are commandable but 4 minutes is a typical setting. These instruments are on many (but not all) GPS satellites which are currently in operation. The data come from either BDD instruments on GPS Block IIR satellites (SVN41 and 48), or else CXD-IIR instruments on GPS Block IIR and IIR-M satellites (SVN53-61) or CXD-IIF instruments on GPS block IIF satellites (SVN62-73). The CXD-IIR instruments on block IIR and IIR(M) satellites use the same design.

GPS operations at Olkiluoto, Kivetty and Romuvaara in 2008

International Nuclear Information System (INIS)

Kallio, U.; Ahola, J.; Koivula, H.; Jokela, J.; Poutanen, M.

2009-09-01

The GPS based deformation studies have been made at the investigation areas of Posiva since 1995, when the network of ten GPS pillars was established at Olkiluoto. The network of seven GPS pillars was built at Kivetty and Romuvaara during the year 1996. One pillar in each investigation area belongs to the Finnish permanent GPS network, FinnRef. A total of 26 GPS measurement campaigns have been carried out at Olkiluoto since 1995, and 17 campaigns at Kivetty and Romuvaara. According to the time series of the GPS results 1/3 of the baselines at Olkiluoto have statistically significant change rates. However, the observed movements are smaller than 0.20 mm/a. The networks of Kivetty and Romuvaara are quite stable expect one pillar at Romuvaara. There are seven pillars, which have statistically significant horizontal velocities at Olkiluoto. These local velocity components are small but taking into account the standard deviations the largest velocity components seems to be reliably determined. The uniform scale for the GPS measurements made in different years is the basic condition for reliable results in the deformation analyses. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured using EDM instruments in connection to the GPS observations. The comparison between the GPS and EDM results can help to fix a possible scale error of the GPS measurements. The GPS network at Olkiluoto was extended in 2003. The new pillars were built close to Kuivalahti village and on a small island of Iso Pyrekari. According to the geological evidence it is expected that a fracture zone is located between the new stations, thus enabling the determination of possible deformations along the fracture zone. The new pillars have been observed since 2003 and now we have computed the first deformation analysis from the six years data. The local crustal deformations have been studied in GeoSatakunta project, too. This GPS network is

GPS operations at Olkiluoto, Kivetty and Romuvaara in 2007

International Nuclear Information System (INIS)

Ahola, J.; Koivula, H.; Jokela, J.

2008-05-01

The GPS based deformation studies have been made at the investigation areas of Posiva since 1995, when the network of ten GPS pillars was established at Olkiluoto. The network of seven GPS pillars was built at Kivetty and Romuvaara during the year 1996. One pillar in each investigation area belongs to the Finnish permanent GPS network, FinnRef. 24 GPS measurement campaigns have been carried out at Olkiluoto since 1995, and 16 campaigns at Kivetty and Romuvaara. According to the time series of the GPS results 1/3 of the baselines at Olkiluoto have statistically significant change rates. However, the observed movements are smaller than ± 0.20 mm/a. The networks of Kivetty and Romuvaara are quite stabile expect one pillar at Romuvaara. There are five pillars, which have statistically significant horizontal velocities at Olkiluoto. These local velocity components are small but taking into account the standard deviations the largest velocity components seems to be reliably determined (maximum velocity is -0.22 mm/a ± 0.02 mm/a). The uniform scale for the GPS measurements made in different years is the basic condition for reliable results in the deformation analyses. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured using EDM instruments simultaneously with the GPS observations. The comparison between the GPS and EDM results can solve a possible scale error of the GPS. The GPS network at Olkiluoto was extended in 2003. The new pillars were built close to Kuivalahti village and on a small island of Iso Pyrekari. According to the geological evidence it is expected that a fracture zone is located between the new stations, thus enabling the determination of possible deformations along the fracture zone. The new pillars have been observed since 2003, but the time series are still too short for reliable deformation studies. The local crustal deformations have been studied in GeoSatakunta project, too. This

Why GPS makes distances bigger than they are.

Science.gov (United States)

Ranacher, Peter; Brunauer, Richard; Trutschnig, Wolfgang; Van der Spek, Stefan; Reich, Siegfried

2016-02-01

Global navigation satellite systems such as the Global Positioning System (GPS) is one of the most important sensors for movement analysis. GPS is widely used to record the trajectories of vehicles, animals and human beings. However, all GPS movement data are affected by both measurement and interpolation errors. In this article we show that measurement error causes a systematic bias in distances recorded with a GPS; the distance between two points recorded with a GPS is - on average - bigger than the true distance between these points. This systematic 'overestimation of distance' becomes relevant if the influence of interpolation error can be neglected, which in practice is the case for movement sampled at high frequencies. We provide a mathematical explanation of this phenomenon and illustrate that it functionally depends on the autocorrelation of GPS measurement error ( C ). We argue that C can be interpreted as a quality measure for movement data recorded with a GPS. If there is a strong autocorrelation between any two consecutive position estimates, they have very similar error. This error cancels out when average speed, distance or direction is calculated along the trajectory. Based on our theoretical findings we introduce a novel approach to determine C in real-world GPS movement data sampled at high frequencies. We apply our approach to pedestrian trajectories and car trajectories. We found that the measurement error in the data was strongly spatially and temporally autocorrelated and give a quality estimate of the data. Most importantly, our findings are not limited to GPS alone. The systematic bias and its implications are bound to occur in any movement data collected with absolute positioning if interpolation error can be neglected.

Assessing fitness for work: GPs judgment making.

Science.gov (United States)

Foley, Michelle; Thorley, Kevan; Van Hout, Marie-Claire

2013-12-01

The complexity of a fitness for work consultation is well documented. General practitioners (GPs) find that such consultations often create conflict and they feel ill-prepared for the task. We aimed to examine the consultation process in the fitness for work consultation and to report on the response of GPs to two hypothetical consultations of work related sickness absence, one of a psychological and one of a physical nature. Three areas of the consultation were examined; social/family circumstances, workplace history and information required assessing the severity of the condition. We used a randomized design using an online questionnaire completed by 62 GPs located in the Republic of Ireland. Analysis was conducted in NVivo 8 qualitative software using thematic and content analysis techniques. GPs may be expected to collect and consider information relating to social, domestic, financial, lifestyle and workplace factors, including workload, job satisfaction, job strain, work ethic, inter staff relationships and employee support mechanisms. The mode of presentation may trigger specific information seeking in the consultation. GPs may evaluate fitness for work in a variety of ways depending on medical and non-medical factors. Further research should further examine the factors that may influence the GPs decision to prescribe sickness leave.

Jump Training in Youth Soccer Players: Effects of Haltere Type Handheld Loading.

Science.gov (United States)

Rosas, F; Ramirez-Campillo, R; Diaz, D; Abad-Colil, F; Martinez-Salazar, C; Caniuqueo, A; Cañas-Jamet, R; Loturco, I; Nakamura, F Y; McKenzie, C; Gonzalez-Rivera, J; Sanchez-Sanchez, J; Izquierdo, M

2016-12-01

The aim of this study was to compare the effects of a jump training program, with or without haltere type handheld loading, on maximal intensity exercise performance. Youth soccer players (12.1±2.2 y) were assigned to either a jump training group (JG, n=21), a jump training group plus haltere type handheld loading (LJG, n=21), or a control group following only soccer training (CG, n=21). Athletes were evaluated for maximal-intensity performance measures before and after 6 weeks of training, during an in-season training period. The CG achieved a significant change in maximal kicking velocity only (ES=0.11-0.20). Both jump training groups improved in right leg (ES=0.28-0.45) and left leg horizontal countermovement jump with arms (ES=0.32-0.47), horizontal countermovement jump with arms (ES=0.28-0.37), vertical countermovement jump with arms (ES=0.26), 20-cm drop jump reactive strength index (ES=0.20-0.37), and maximal kicking velocity (ES=0.27-0.34). Nevertheless, compared to the CG, only the LJG exhibited greater improvements in all performance tests. Therefore, haltere type handheld loading further enhances performance adaptations during jump training in youth soccer players. © Georg Thieme Verlag KG Stuttgart · New York.

Application of Handheld Tele-ECG for Health Care Delivery in Rural India

Directory of Open Access Journals (Sweden)

Meenu Singh

2014-01-01

Full Text Available Telemonitoring is a medical practice that involves remotely monitoring patients who are not at the same location as the health care provider. The purpose of our study was to use handheld tele-electrocardiogram (ECG developed by Bhabha Atomic Research Center (BARC to identify heart conditions in the rural underserved population where the doctor-patient ratio is low and access to health care is difficult. The objective of our study was clinical validation of handheld tele-ECG as a screening tool for evaluation of cardiac diseases in the rural population. ECG was obtained in 450 individuals (mean age 31.49 ± 20.058 residing in the periphery of Chandigarh, India, from April 2011 to March 2013, using the handheld tele-ECG machine. The data were then transmitted to physicians in Postgraduate Institute of Medical Education and Research (PGIMER, Chandigarh, for their expert opinion. ECG was interpreted as normal in 70% individuals. Left ventricular hypertrophy (9.3% was the commonest abnormality followed closely by old myocardial infarction (5.3%. Patient satisfaction was reported to be ~95%. Thus, it can be safely concluded that tele-ECG is a portable, cost-effective, and convenient tool for diagnosis and monitoring of heart diseases and thus improves quality and accessibility, especially in rural areas.

GPS Modeling and Analysis. Summary of Research: GPS Satellite Axial Ratio Predictions

Science.gov (United States)

Axelrad, Penina; Reeh, Lisa

2002-01-01

This report outlines the algorithms developed at the Colorado Center for Astrodynamics Research to model yaw and predict the axial ratio as measured from a ground station. The algorithms are implemented in a collection of Matlab functions and scripts that read certain user input, such as ground station coordinates, the UTC time, and the desired GPS (Global Positioning System) satellites, and compute the above-mentioned parameters. The position information for the GPS satellites is obtained from Yuma almanac files corresponding to the prescribed date. The results are displayed graphically through time histories and azimuth-elevation plots.

Azimuth selection for sea level measurements using geodetic GPS receivers

Science.gov (United States)

Wang, Xiaolei; Zhang, Qin; Zhang, Shuangcheng

2018-03-01

Based on analysis of Global Positioning System (GPS) multipath signals recorded by a geodetic GPS receiver, GPS Reflectometry (GPS-R) has demonstrated unique advantages in relation to sea level monitoring. Founded on multipath reflectometry theory, sea level changes can be measured by GPS-R through spectral analysis of recorded signal-to-noise ratio data. However, prior to estimating multipath parameters, it is necessary to define azimuth and elevation angle mask to ensure the reflecting zones are on water. Here, a method is presented to address azimuth selection, a topic currently under active development in the field of GPS-R. Data from three test sites: the Kachemak Bay GPS site PBAY in Alaska (USA), Friday Harbor GPS site SC02 in the San Juan Islands (USA), and Brest Harbor GPS site BRST in Brest (France) are analyzed. These sites are located in different multipath environments, from a rural coastal area to a busy harbor, and they experience different tidal ranges. Estimates by the GPS tide gauges at azimuths selected by the presented method are compared with measurements from physical tide gauges and acceptable correspondence found for all three sites.

The Evolution of Global Positioning System (GPS) Technology.

Science.gov (United States)

Kumar, Sameer; Moore, Kevin B.

2002-01-01

Describes technological advances in the Global Positioning System (GPS), which is also known as the NAVSTAR GPS satellite constellation program developed in 1937, and changes in the nature of our world by GPS in the areas of agriculture, health, military, transportation, environment, wildlife biology, surveying and mapping, space applications, and…

Observing Tsunamis in the Ionosphere Using Ground Based GPS Measurements

Science.gov (United States)

Galvan, D. A.; Komjathy, A.; Song, Y. Tony; Stephens, P.; Hickey, M. P.; Foster, J.

2011-01-01

Ground-based Global Positioning System (GPS) measurements of ionospheric Total Electron Content (TEC) show variations consistent with atmospheric internal gravity waves caused by ocean tsunamis following recent seismic events, including the Tohoku tsunami of March 11, 2011. We observe fluctuations correlated in time, space, and wave properties with this tsunami in TEC estimates processed using JPL's Global Ionospheric Mapping Software. These TEC estimates were band-pass filtered to remove ionospheric TEC variations with periods outside the typical range of internal gravity waves caused by tsunamis. Observable variations in TEC appear correlated with the Tohoku tsunami near the epicenter, at Hawaii, and near the west coast of North America. Disturbance magnitudes are 1-10% of the background TEC value. Observations near the epicenter are compared to estimates of expected tsunami-driven TEC variations produced by Embry Riddle Aeronautical University's Spectral Full Wave Model, an atmosphere-ionosphere coupling model, and found to be in good agreement. The potential exists to apply these detection techniques to real-time GPS TEC data, providing estimates of tsunami speed and amplitude that may be useful for future early warning systems.

Inversion of GPS meteorology data

Directory of Open Access Journals (Sweden)

K. Hocke

Full Text Available The GPS meteorology (GPS/MET experiment, led by the Universities Corporation for Atmospheric Research (UCAR, consists of a GPS receiver aboard a low earth orbit (LEO satellite which was launched on 3 April 1995. During a radio occultation the LEO satellite rises or sets relative to one of the 24 GPS satellites at the Earth's horizon. Thereby the atmospheric layers are successively sounded by radio waves which propagate from the GPS satellite to the LEO satellite. From the observed phase path increases, which are due to refraction of the radio waves by the ionosphere and the neutral atmosphere, the atmospheric parameter refractivity, density, pressure and temperature are calculated with high accuracy and resolution (0.5–1.5 km. In the present study, practical aspects of the GPS/MET data analysis are discussed. The retrieval is based on the Abelian integral inversion of the atmospheric bending angle profile into the refractivity index profile. The problem of the upper boundary condition of the Abelian integral is described by examples. The statistical optimization approach which is applied to the data above 40 km and the use of topside bending angle profiles from model atmospheres stabilize the inversion. The retrieved temperature profiles are compared with corresponding profiles which have already been calculated by scientists of UCAR and Jet Propulsion Laboratory (JPL, using Abelian integral inversion too. The comparison shows that in some cases large differences occur (5 K and more. This is probably due to different treatment of the upper boundary condition, data runaways and noise. Several temperature profiles with wavelike structures at tropospheric and stratospheric heights are shown. While the periodic structures at upper stratospheric heights could be caused by residual errors of the ionospheric correction method, the periodic temperature fluctuations at heights below 30 km are most likely caused by atmospheric waves (vertically

Towards Vision-Based Control of a Handheld Micromanipulator for Retinal Cannulation in an Eyeball Phantom

Science.gov (United States)

Becker, Brian C.; Yang, Sungwook; MacLachlan, Robert A.; Riviere, Cameron N.

2012-01-01

Injecting clot-busting drugs such as t-PA into tiny vessels thinner than a human hair in the eye is a challenging procedure, especially since the vessels lie directly on top of the delicate and easily damaged retina. Various robotic aids have been proposed with the goal of increasing safety by removing tremor and increasing precision with motion scaling. We have developed a fully handheld micromanipulator, Micron, that has demonstrated reduced tremor when cannulating porcine retinal veins in an “open sky” scenario. In this paper, we present work towards handheld robotic cannulation with the goal of vision-based virtual fixtures guiding the tip of the cannula to the vessel. Using a realistic eyeball phantom, we address sclerotomy constraints, eye movement, and non-planar retina. Preliminary results indicate a handheld micromanipulator aided by visual control is a promising solution to retinal vessel occlusion. PMID:24649479

GPS queues with heterogeneous traffic classes

NARCIS (Netherlands)

Borst, Sem; Mandjes, M.R.H.; van Uitert, Miranda

2002-01-01

We consider a queue fed by a mixture of light-tailed and heavy-tailed traffic. The two traffic classes are served in accordance with the generalized processor sharing (GPS) discipline. GPS-based scheduling algorithms, such as weighted fair queueing (WFQ), have emerged as an important mechanism for

Performance Analysis of Several GPS/Galileo Precise Point Positioning Models.

Science.gov (United States)

Afifi, Akram; El-Rabbany, Ahmed

2015-06-19

This paper examines the performance of several precise point positioning (PPP) models, which combine dual-frequency GPS/Galileo observations in the un-differenced and between-satellite single-difference (BSSD) modes. These include the traditional un-differenced model, the decoupled clock model, the semi-decoupled clock model, and the between-satellite single-difference model. We take advantage of the IGS-MGEX network products to correct for the satellite differential code biases and the orbital and satellite clock errors. Natural Resources Canada's GPSPace PPP software is modified to handle the various GPS/Galileo PPP models. A total of six data sets of GPS and Galileo observations at six IGS stations are processed to examine the performance of the various PPP models. It is shown that the traditional un-differenced GPS/Galileo PPP model, the GPS decoupled clock model, and the semi-decoupled clock GPS/Galileo PPP model improve the convergence time by about 25% in comparison with the un-differenced GPS-only model. In addition, the semi-decoupled GPS/Galileo PPP model improves the solution precision by about 25% compared to the traditional un-differenced GPS/Galileo PPP model. Moreover, the BSSD GPS/Galileo PPP model improves the solution convergence time by about 50%, in comparison with the un-differenced GPS PPP model, regardless of the type of BSSD combination used. As well, the BSSD model improves the precision of the estimated parameters by about 50% and 25% when the loose and the tight combinations are used, respectively, in comparison with the un-differenced GPS-only model. Comparable results are obtained through the tight combination when either a GPS or a Galileo satellite is selected as a reference.

Performance of GPS-devices for environmental exposure assessment.

Science.gov (United States)

Beekhuizen, Johan; Kromhout, Hans; Huss, Anke; Vermeulen, Roel

2013-01-01

Integration of individual time-location patterns with spatially resolved exposure maps enables a more accurate estimation of personal exposures to environmental pollutants than using estimates at fixed locations. Current global positioning system (GPS) devices can be used to track an individual's location. However, information on GPS-performance in environmental exposure assessment is largely missing. We therefore performed two studies. First, a commute-study, where the commute of 12 individuals was tracked twice, testing GPS-performance for five transport modes and two wearing modes. Second, an urban-tracking study, where one individual was tracked repeatedly through different areas, focused on the effect of building obstruction on GPS-performance. The median error from the true path for walking was 3.7 m, biking 2.9 m, train 4.8 m, bus 4.9 m, and car 3.3 m. Errors were larger in a high-rise commercial area (median error=7.1 m) compared with a low-rise residential area (median error=2.2 m). Thus, GPS-performance largely depends on the transport mode and urban built-up. Although ~85% of all errors were 50 m. Modern GPS-devices are useful tools for environmental exposure assessment, but large GPS-errors might affect estimates of exposures with high spatial variability.

MEMS-based handheld fourier domain Doppler optical coherence tomography for intraoperative microvascular anastomosis imaging.

Directory of Open Access Journals (Sweden)

Yong Huang

Full Text Available To demonstrate the feasibility of a miniature handheld optical coherence tomography (OCT imager for real time intraoperative vascular patency evaluation in the setting of super-microsurgical vessel anastomosis.A novel handheld imager Fourier domain Doppler optical coherence tomography based on a 1.3-µm central wavelength swept source for extravascular imaging was developed. The imager was minimized through the adoption of a 2.4-mm diameter microelectromechanical systems (MEMS scanning mirror, additionally a 12.7-mm diameter lens system was designed and combined with the MEMS mirror to achieve a small form factor that optimize functionality as a handheld extravascular OCT imager. To evaluate in-vivo applicability, super-microsurgical vessel anastomosis was performed in a mouse femoral vessel cut and repair model employing conventional interrupted suture technique as well as a novel non-suture cuff technique. Vascular anastomosis patency after clinically successful repair was evaluated using the novel handheld OCT imager.With an adjustable lateral image field of view up to 1.5 mm by 1.5 mm, high-resolution simultaneous structural and flow imaging of the blood vessels were successfully acquired for BALB/C mouse after orthotopic hind limb transplantation using a non-suture cuff technique and BALB/C mouse after femoral artery anastomosis using a suture technique. We experimentally quantify the axial and lateral resolution of the OCT to be 12.6 µm in air and 17.5 µm respectively. The OCT has a sensitivity of 84 dB and sensitivity roll-off of 5.7 dB/mm over an imaging range of 5 mm. Imaging with a frame rate of 36 Hz for an image size of 1000(lateral×512(axial pixels using a 50,000 A-lines per second swept source was achieved. Quantitative vessel lumen patency, lumen narrowing and thrombosis analysis were performed based on acquired structure and Doppler images.A miniature handheld OCT imager that can be used for intraoperative evaluation of

Ultra-compact swept-source optical coherence tomography handheld probe with motorized focus adjustment (Conference Presentation)

Science.gov (United States)

LaRocca, Francesco; Nankivil, Derek; Keller, Brenton; Farsiu, Sina; Izatt, Joseph A.

2017-02-01

Handheld optical coherence tomography (OCT) systems facilitate imaging of young children, bedridden subjects, and those with less stable fixation. Smaller and lighter OCT probes allow for more efficient imaging and reduced operator fatigue, which is critical for prolonged use in either the operating room or neonatal intensive care unit. In addition to size and weight, the imaging speed, image quality, field of view, resolution, and focus correction capability are critical parameters that determine the clinical utility of a handheld probe. Here, we describe an ultra-compact swept source (SS) OCT handheld probe weighing only 211 g (half the weight of the next lightest handheld SSOCT probe in the literature) with 20.1 µm lateral resolution, 7 µm axial resolution, 102 dB peak sensitivity, a 27° x 23° field of view, and motorized focus adjustment for refraction correction between -10 to +16 D. A 2D microelectromechanical systems (MEMS) scanner, a converging beam-at-scanner telescope configuration, and an optical design employing 6 different custom optics were used to minimize device size and weight while achieving diffraction limited performance throughout the system's field of view. Custom graphics processing unit (GPU)-accelerated software was used to provide real-time display of OCT B-scans and volumes. Retinal images were acquired from adult volunteers to demonstrate imaging performance.

GPS operations at Olkiluoto, Kivetty and Romuvaara in 2006

International Nuclear Information System (INIS)

Ahola, J.; Koivula, H.; Poutanen, M.; Jokela, J.

2007-05-01

The GPS based deformation studies have been made at the investigation areas of Posiva since 1995, when the network of ten GPS pillars was established at Olkiluoto. The network of seven GPS pillars was built at Kivetty and Romuvaara during the year 1996. One pillar in each investigation area belongs to the Finnish permanent GPS network, FinnRef. 22 GPS measurement campaigns have been carried out at Olkiluoto since 1995, and 15 campaigns at Kivetty and Romuvaara. According to the time series of the GPS results 1/3 of the baselines at Olkiluoto have statistically significant change rates. However, the observed movements are smaller than ± 0.22 mm/a. The networks of Kivetty and Romuvaara are quite stabile expect one pillar at Romuvaara. There are five pillars, which have statistically significant horizontal velocities at Olkiluoto. These local velocity components are small but taking into account the standard deviations the largest velocity components seems to be reliably determined (maximum velocity is -0.23 mm/a ± 0.023 mm/a). The uniform scale for the GPS measurements made in different years is the basic condition for reliable results in the deformation analyses. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured using EDM instruments simultaneously with the GPS observations. The comparison between the GPS and EDM results can solve a possible scale error of the GPS. The GPS network at Olkiluoto was extended in 2003. The new pillars were built close to Kuivalahti village and on a small island of Iso Pyrekari. According to the geological evidence it is expected that a fracture zone is located between the new stations, thus enabling the determination of possible deformations along the fracture zone. The new pillars have been observed since 2003, but the time series are still too short for reliable deformation studies. The local crustal deformations have been studied in GeoSatakunta project, too. This

Application of GPS systems on a mobile robot

Science.gov (United States)

Cao, Peter; Saxena, Mayank; Tedder, Maurice; Mischalske, Steve; Hall, Ernest L.

2001-10-01

The purpose of this paper is to describe the use of Global Positioning Systems (GPS) as geographic information and navigational system for a ground based mobile robot. Several low cost wireless systems are now available for a variety of innovative automobile applications including location, messaging and tracking and security. Experiments were conducted with a test bed mobile robot, Bearcat II, for point-to-point motion using a Motorola GPS in June 2001. The Motorola M12 Oncore GPS system is connected to the Bearcat II main control computer through a RS232 interface. A mapping program is used to define a desired route. Then GPS information may be displayed for verification. However, the GPS information is also used to update the control points of the mobile robot using a reinforcement learning method. Local position updates are also used when found in the environment. The significance of the method is in extending the use of GPS to local vehicle control that requires more resolution that is available from the raw data using the adaptive control method.

Quality-Based Backlight Optimization for Video Playback on Handheld Devices

Directory of Open Access Journals (Sweden)

Liang Cheng

2007-01-01

Full Text Available For a typical handheld device, the backlight accounts for a significant percentage of the total energy consumption (e.g., around 30% for a Compaq iPAQ 3650. Substantial energy savings can be achieved by dynamically adapting backlight intensity levels on such low-power portable devices. In this paper, we analyze the characteristics of video streaming services and propose a cross-layer optimization scheme called quality adapted backlight scaling (QABS to achieve backlight energy savings for video playback applications on handheld devices. Specifically, we present a fast algorithm to optimize backlight dimming while keeping the degradation in image quality to a minimum so that the overall service quality is close to a specified threshold. Additionally, we propose two effective techniques to prevent frequent backlight switching, which negatively affects user perception of video. Our initial experimental results indicate that the energy used for backlight is significantly reduced, while the desired quality is satisfied. The proposed algorithms can be realized in real time.

A conceptual application for computer-based procedures for handheld devices

Energy Technology Data Exchange (ETDEWEB)

Sofie, Lunde-Hanssen Linda [Industrial Psychology, Institute for Energy Technology, Halden (Norway)

2014-08-15

This paper describes the concepts and proposed design principles for an application for computer-based procedures (CBPs) for field operators in the nuclear domain (so-called handheld procedures). The concept is focused on the field operators' work with procedures and the communication and coordination between field operators and control room operators. The goal is to overcome challenges with shared situation awareness (SA) in a distributed team by providing effective and usable information design. An iterative design method and user-centred design is used for tailoring the concept to the context of field operations. The resulting concept supports the execution of procedures where close collaboration is needed between control room and field operations, e.g. where particular procedure steps are executed from remote control points and others from the control room. The resulting conceptual application for CBPs on handheld devices is developed for mitigating the SA challenges and designing for usability and ease of use.

A conceptual application for computer-based procedures for handheld devices

International Nuclear Information System (INIS)

Sofie, Lunde-Hanssen Linda

2014-01-01

This paper describes the concepts and proposed design principles for an application for computer-based procedures (CBPs) for field operators in the nuclear domain (so-called handheld procedures). The concept is focused on the field operators' work with procedures and the communication and coordination between field operators and control room operators. The goal is to overcome challenges with shared situation awareness (SA) in a distributed team by providing effective and usable information design. An iterative design method and user-centred design is used for tailoring the concept to the context of field operations. The resulting concept supports the execution of procedures where close collaboration is needed between control room and field operations, e.g. where particular procedure steps are executed from remote control points and others from the control room. The resulting conceptual application for CBPs on handheld devices is developed for mitigating the SA challenges and designing for usability and ease of use

Software Defined GPS Receiver for International Space Station

Science.gov (United States)

Duncan, Courtney B.; Robison, David E.; Koelewyn, Cynthia Lee

2011-01-01

JPL is providing a software defined radio (SDR) that will fly on the International Space Station (ISS) as part of the CoNNeCT project under NASA's SCaN program. The SDR consists of several modules including a Baseband Processor Module (BPM) and a GPS Module (GPSM). The BPM executes applications (waveforms) consisting of software components for the embedded SPARC processor and logic for two Virtex II Field Programmable Gate Arrays (FPGAs) that operate on data received from the GPSM. GPS waveforms on the SDR are enabled by an L-Band antenna, low noise amplifier (LNA), and the GPSM that performs quadrature downconversion at L1, L2, and L5. The GPS waveform for the JPL SDR will acquire and track L1 C/A, L2C, and L5 GPS signals from a CoNNeCT platform on ISS, providing the best GPS-based positioning of ISS achieved to date, the first use of multiple frequency GPS on ISS, and potentially the first L5 signal tracking from space. The system will also enable various radiometric investigations on ISS such as local multipath or ISS dynamic behavior characterization. In following the software-defined model, this work will create a highly portable GPS software and firmware package that can be adapted to another platform with the necessary processor and FPGA capability. This paper also describes ISS applications for the JPL CoNNeCT SDR GPS waveform, possibilities for future global navigation satellite system (GNSS) tracking development, and the applicability of the waveform components to other space navigation applications.

GPS-Aided Video Tracking

Directory of Open Access Journals (Sweden)

Udo Feuerhake

2015-08-01

Full Text Available Tracking moving objects is both challenging and important for a large variety of applications. Different technologies based on the global positioning system (GPS and video or radio data are used to obtain the trajectories of the observed objects. However, in some use cases, they fail to provide sufficiently accurate, complete and correct data at the same time. In this work we present an approach for fusing GPS- and video-based tracking in order to exploit their individual advantages. In this way we aim to combine the reliability of GPS tracking with the high geometric accuracy of camera detection. For the fusion of the movement data provided by the different devices we use a hidden Markov model (HMM formulation and the Viterbi algorithm to extract the most probable trajectories. In three experiments, we show that our approach is able to deal with challenging situations like occlusions or objects which are temporarily outside the monitored area. The results show the desired increase in terms of accuracy, completeness and correctness.

Geomagnetic storm effects on GPS based navigation

Directory of Open Access Journals (Sweden)

P. V. S. Rama Rao

2009-05-01

Full Text Available The energetic events on the sun, solar wind and subsequent effects on the Earth's geomagnetic field and upper atmosphere (ionosphere comprise space weather. Modern navigation systems that use radio-wave signals, reflecting from or propagating through the ionosphere as a means of determining range or distance, are vulnerable to a variety of effects that can degrade the performance of the navigational systems. In particular, the Global Positioning System (GPS that uses a constellation of earth orbiting satellites are affected due to the space weather phenomena.

Studies made during two successive geomagnetic storms that occurred during the period from 8 to 12 November 2004, have clearly revealed the adverse affects on the GPS range delay as inferred from the Total Electron Content (TEC measurements made from a chain of seven dual frequency GPS receivers installed in the Indian sector. Significant increases in TEC at the Equatorial Ionization anomaly crest region are observed, resulting in increased range delay during the periods of the storm activity. Further, the storm time rapid changes occurring in TEC resulted in a number of phase slips in the GPS signal compared to those on quiet days. These phase slips often result in the loss of lock of the GPS receivers, similar to those that occur during strong(>10 dB L-band scintillation events, adversely affecting the GPS based navigation.

High-sensitivity modified Glasgow prognostic score (HS-mGPS) Is superior to the mGPS in esophageal cancer patients treated with chemoradiotherapy

OpenAIRE

Chen, Peng; Fang, Min; Wan, Qiuyan; Zhang, Xuebang; Song, Tao; Wu, Shixiu

2017-01-01

The present study compared the prognostic value of the modified Glasgow prognostic score (mGPS) and high-sensitivity mGPS (HS-mGPS) in unresectable locally advanced esophageal squamous cell carcimona (LAESCC) patients treated with concurrent chemoradiotherapy (CCRT). The baseline data of 163 eligible patients were retrospectively collected. Patients with a C-reactive protein (CRP) ≤ 10 mg/l and albumin ≥ 35 g/l were allocated to mGPS-0 group. Patients with only elevated CRP (> 10 mg/l) were a...

Estimering af brændstofforbrug vha. GPS Data

DEFF Research Database (Denmark)

Andersen, Ove; Lahrmann, Harry; Torp, Kristian

2010-01-01

Det er simpelt og billigt at opsamle GPS målinger fra køretøjer. Når større mængder GPS data indsamles fra et passende antal køretøjer kan dataen bruges til at beregne f.eks. køretider. Det er ligeledes muligt ud fra GPS data at estimere miljøindikatorer så som, hvor aggressivt kører bilister og er...... der nogle vejstrækninger, der har en højere (negativ) miljø påvirkning end andre? I denne artikel præsenterer et forsøg, hvor GPS data anvendes til at estimere brændstofforbruget ved en enkelt tur og for vejnettet generelt. Dette gøres ved at opbygge en database med GPS data. Ud fra disse data gives...

Interseismic Coupling on the Quito Fault System in Ecuador Using New GPS and InSAR Data and Its Implication on Seismic Hazard Assessment.

Science.gov (United States)

Mariniere, J.; Champenois, J.; Nocquet, J. M.; Beauval, C. M.; Audin, L.; Baize, S.; Alvarado, A. P.; Yepes, H. A.; Jomard, H.

2017-12-01

Quito, the capital of Ecuador hosting two million inhabitants lies on an active reverse fault system within the Andes. Regular moderate size earthquakes (M 5) occur on these faults, widely felt within the city and its surrounding. Despite a relatively small magnitude of Mw 5.1, the 2014 August 12 earthquake triggered landslides that killed 4 people, cut off one of the main highways for several weeks and caused the temporary shutdown of the airport. Quantifying the seismic potential of the Quito fault system is therefore crucial for a better preparation and mitigation to seismic risk. Previous work using a limited GPS data set found that the Quito fault accommodates 4 mm/yr of EW shortening (Alvarado et al., 2014) at shallow locking depths (3-7 km). We combine GPS and new InSAR data to extend the previous analysis and better quantify the spatial distribution of locking of the Quito fault. GPS dataset includes new continuous sites operating since 2013. 18 ERS SAR scenes, spanning the 1993-2000 time period and covering an area of 85 km by 30 km, were processed using a Permanent Scatter strategy. We perform a joint inversion of both data set (GPS and InSAR) to infer a new and better-constrained kinematic model of the fault to determine both the slip rate and the locking distribution at depth. We find a highly variable level of locking which changes along strike. At some segments, sharp displacement gradients observed both for GPS and InSAR suggest that the fault is creeping up to the surface, while shallow locking is found for other segments. Previous Probabilistic Seismic Hazard Assessment studies have shown that the Quito fault fully controls the hazard in Quito city (Beauval et al. 2014). The results will be used to improve the forecast of earthquakes on the Quito fault system for PSHA studies.

Handheld Nonlinear Detection of Delamination and Intrusion Faults in Composites, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — In Phase I of the SBIR program, LEEOAT Company will develop a hand-held high-resolution ultrasonic nonlinear imager for non-destructive inspection (NDI) of...

Combining heterogenous features for 3D hand-held object recognition

Science.gov (United States)

Lv, Xiong; Wang, Shuang; Li, Xiangyang; Jiang, Shuqiang

2014-10-01

Object recognition has wide applications in the area of human-machine interaction and multimedia retrieval. However, due to the problem of visual polysemous and concept polymorphism, it is still a great challenge to obtain reliable recognition result for the 2D images. Recently, with the emergence and easy availability of RGB-D equipment such as Kinect, this challenge could be relieved because the depth channel could bring more information. A very special and important case of object recognition is hand-held object recognition, as hand is a straight and natural way for both human-human interaction and human-machine interaction. In this paper, we study the problem of 3D object recognition by combining heterogenous features with different modalities and extraction techniques. For hand-craft feature, although it reserves the low-level information such as shape and color, it has shown weakness in representing hiconvolutionalgh-level semantic information compared with the automatic learned feature, especially deep feature. Deep feature has shown its great advantages in large scale dataset recognition but is not always robust to rotation or scale variance compared with hand-craft feature. In this paper, we propose a method to combine hand-craft point cloud features and deep learned features in RGB and depth channle. First, hand-held object segmentation is implemented by using depth cues and human skeleton information. Second, we combine the extracted hetegerogenous 3D features in different stages using linear concatenation and multiple kernel learning (MKL). Then a training model is used to recognize 3D handheld objects. Experimental results validate the effectiveness and gerneralization ability of the proposed method.

78 FR 27441 - NIJ Evaluation of Hand-Held Cell Phone Detector Devices

Science.gov (United States)

2013-05-10

...The National Institute of Justice (NIJ) is soliciting interest in supplying hand-held cell phone detector devices for participation in an evaluation by the NIJ Corrections Technology Center of Excellence (CXCoE).

Single-Receiver GPS Phase Bias Resolution

Science.gov (United States)

Bertiger, William I.; Haines, Bruce J.; Weiss, Jan P.; Harvey, Nathaniel E.

2010-01-01

Existing software has been modified to yield the benefits of integer fixed double-differenced GPS-phased ambiguities when processing data from a single GPS receiver with no access to any other GPS receiver data. When the double-differenced combination of phase biases can be fixed reliably, a significant improvement in solution accuracy is obtained. This innovation uses a large global set of GPS receivers (40 to 80 receivers) to solve for the GPS satellite orbits and clocks (along with any other parameters). In this process, integer ambiguities are fixed and information on the ambiguity constraints is saved. For each GPS transmitter/receiver pair, the process saves the arc start and stop times, the wide-lane average value for the arc, the standard deviation of the wide lane, and the dual-frequency phase bias after bias fixing for the arc. The second step of the process uses the orbit and clock information, the bias information from the global solution, and only data from the single receiver to resolve double-differenced phase combinations. It is called "resolved" instead of "fixed" because constraints are introduced into the problem with a finite data weight to better account for possible errors. A receiver in orbit has much shorter continuous passes of data than a receiver fixed to the Earth. The method has parameters to account for this. In particular, differences in drifting wide-lane values must be handled differently. The first step of the process is automated, using two JPL software sets, Longarc and Gipsy-Oasis. The resulting orbit/clock and bias information files are posted on anonymous ftp for use by any licensed Gipsy-Oasis user. The second step is implemented in the Gipsy-Oasis executable, gd2p.pl, which automates the entire process, including fetching the information from anonymous ftp

Optical links in handheld multimedia devices

Science.gov (United States)

van Geffen, S.; Duis, J.; Miller, R.

2008-04-01

Ever emerging applications in handheld multimedia devices such as mobile phones, laptop computers, portable video games and digital cameras requiring increased screen resolutions are driving higher aggregate bitrates between host processor and display(s) enabling services such as mobile video conferencing, video on demand and TV broadcasting. Larger displays and smaller phones require complex mechanical 3D hinge configurations striving to combine maximum functionality with compact building volumes. Conventional galvanic interconnections such as Micro-Coax and FPC carrying parallel digital data between host processor and display module may produce Electromagnetic Interference (EMI) and bandwidth limitations caused by small cable size and tight cable bends. To reduce the number of signals through a hinge, the mobile phone industry, organized in the MIPI (Mobile Industry Processor Interface) alliance, is currently defining an electrical interface transmitting serialized digital data at speeds >1Gbps. This interface allows for electrical or optical interconnects. Above 1Gbps optical links may offer a cost effective alternative because of their flexibility, increased bandwidth and immunity to EMI. This paper describes the development of optical links for handheld communication devices. A cable assembly based on a special Plastic Optical Fiber (POF) selected for its mechanical durability is terminated with a small form factor molded lens assembly which interfaces between an 850nm VCSEL transmitter and a receiving device on the printed circuit board of the display module. A statistical approach based on a Lean Design For Six Sigma (LDFSS) roadmap for new product development tries to find an optimum link definition which will be robust and low cost meeting the power consumption requirements appropriate for battery operated systems.

How and Why to Do VLBI on GPS

Science.gov (United States)

Dickey, J. M.

2010-01-01

In order to establish the position of the center of mass of the Earth in the International Celestial Reference Frame, observations of the Global Positioning Satellite (GPS) constellation using the IVS network are important. With a good frame-tie between the coordinates of the IVS telescopes and nearby GPS receivers, plus a common local oscillator reference signal, it should be possible to observe and record simultaneously signals from the astrometric calibration sources and the GPS satellites. The standard IVS solution would give the atmospheric delay and clock offsets to use in analysis of the GPS data. Correlation of the GPS signals would then give accurate orbital parameters of the satellites in the ICRF reference frame, i.e., relative to the positions of the astrometric sources. This is particularly needed to determine motion of the center of mass of the earth along the rotation axis.

Localization system for use in GPS denied environments

Energy Technology Data Exchange (ETDEWEB)

Trueblood, J. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-02-01

The military uses to autonomous platforms to complete missions to provide standoff for the warfighters. However autonomous platforms rely on GPS to provide their global position. In many missions spaces the autonomous platforms may encounter GPS denied environments which limits where the platform operates and requires the warfighters to takes its place. GPS denied environments can occur due to tall building, trees, canyon wall blocking the GPS satellite signals or a lack of coverage. An Inertial Navigation System (INS) uses sensors to detect the vehicle movement and direction its traveling to calculate the vehicle. One of biggest challenges with an INS system is the accuracy and accumulation of errors over time of the sensors. If these challenges can be overcome the INS would provide accurate positioning information to the autonomous vehicle in GPS denied environments and allow them to provide the desired standoff for the warfighters.

Improvement of registration accuracy of a handheld augmented reality system for urban landscape simulation

Directory of Open Access Journals (Sweden)

Tomohiro Fukuda

2014-12-01

Full Text Available The need for visual landscape assessment in large-scale projects for the evaluation of the effects of a particular project on the surrounding landscape has grown in recent years. Augmented reality (AR has been considered for use as a landscape simulation system in which a landscape assessment object created by 3D models is included in the present surroundings. With the use of this system, the time and the cost needed to perform a 3DCG modeling of present surroundings, which is a major issue in virtual reality, are drastically reduced. This research presents the development of a 3D map-oriented handheld AR system that achieves geometric consistency using a 3D map to obtain position data instead of GPS, which has low position information accuracy, particularly in urban areas. The new system also features a gyroscope sensor to obtain posture data and a video camera to capture live video of the present surroundings. All these components are mounted in a smartphone and can be used for urban landscape assessment. Registration accuracy is evaluated to simulate an urban landscape from a short- to a long-range scale. The latter involves a distance of approximately 2000 m. The developed AR system enables users to simulate a landscape from multiple and long-distance viewpoints simultaneously and to walk around the viewpoint fields using only a smartphone. This result is the tolerance level of landscape assessment. In conclusion, the proposed method is evaluated as feasible and effective.

GPS antenna designs

Science.gov (United States)

Laube, Samuel J. P.

1987-05-01

Application of the current GPS NAVSTAR system to civilian service requires that a right hand, circularly polarized, -160 dBW spread spectrum signal be received from an orbiting satellite, where the antenna environment is also moving. This presents a design challenge when inexpensive antennas are desired. The intent of this survey is to provide information on the antennas mentioned and to construct and test prototypes to determine whether the choice made by the industry, the quadrifilar helix, is the best. The helix antenna is currently the low cost standard for GPS. Prototype versions were constructed using 12 gauge wire and subminiature coaxial hardline. The constructed antennas were tested using a signal generator and a reference turnstile. A spectrum analyzer was used to measure the level of the received signal.

Audiovisual Presentations on a Handheld PC are Preferred As an Educational Tool by NICU Parents.

Science.gov (United States)

Alur, P; Cirelli, J; Goodstein, M; Bell, T; Liss, J

2010-01-01

Health literacy is critical for understanding complex medical problems and necessary for the well being of the patient. Printed educational materials (PM) have limitations in explaining the dynamics of a disease process. Multimedia formats may be useful for enhancing the educational process. To evaluate whether a printed format or animation with commentary on a handheld personal computer (PC) is preferred as an educational tool by parents of a baby in the NICU. PARENTS EVALUATED TWO FORMATS: A 1-page illustrated document from the American Heart Association explaining patent ductus arteriosus (PDA) and animation with commentary on a handheld PC that explained the physiology of PDA in 1 minute. The reading grade level of the PM was 8.6 versus 18.6 for the audio portion of the animated presentation. Parents viewed each format and completed a four-item questionnaire. Parents rated both formats and indicated their preference as printed, animation, or both. Forty-six parents participated in the survey. Parents preferred animation over PM (50% vs. 17.4%. p = 0.02); 39.1% expressed that the animation was excellent; whereas 4.3% expressed that the PM was excellent (p0.05). Parents preferred animation on a small screen handheld PC despite a much higher language level. Because handheld PCs are portable and inexpensive, they can be used effectively at the bedside with low-cost animation to enhance understanding of complex disease conditions.

Epidemiology of Handheld Cell Phone Use While Driving: A Study from a South Indian City

Directory of Open Access Journals (Sweden)

Sumanth Mallikarjuna Majgi

2018-01-01

Full Text Available Background: Using cell phones while driving contribute to distractions which can potentially cause minor or major road traffic injuries and also stress among other drivers. With this background, the study was done to ascertain the proportion of handheld cell phone use while driving among road users in Mysore city and also patterns of the use by the day of week, type of road, and type of vehicle. Methods: The study was conducted in Mysore, Karnataka, India. Four stretches of roads were observed thrice daily for 1 week. The total number of vehicles passing through the stretch and the number and characteristics of drivers using hand-held cell was noted. Pearson's Chi-square test was used to ascertain the significance of the difference in proportions. Results: The overall proportion of cell phone users was calculated as 1.41/100 vehicles. The observed use of handheld cell phones was 1.78 times higher on nonbusy roads than busy roads (Χ2 = 25.79, P < 0.0001. More than 50% of the handheld phone users were driving a two wheeler, the proportion being 50.5% in busy roads, and 67% in nonbusy roads. There was no difference in the proportion of cell phone use by time of the day or across different days of the week. Conclusions: The proportion of drivers who use cell phones is found to be relatively lower, and use of cell phones was higher on nonbusy roads.

The use of the AOA TTR-4P GPS receiver in operation at the BIPM for real-time restitution of GPS time

Science.gov (United States)

Thomas, Claudine

1994-01-01

The Global Positioning System is an outstanding tool for the dissemination of time. Using mono-channel C/A-code GPS time receivers, the restitution of GPS time through the satellite constellation presents a peak-to-peak discrepancy of several tens of nanoseconds without SA but may be as high as several hundreds of nanoseconds with SA. As a consequence, civil users are more and more interested in implementing hardware and software methods for efficient restitution of GPS time, especially in the framework of the project of a real-time prediction of UTC (UTCp) which could be available in the form of time differences (UTCp - GPS time). Previous work, for improving the real-time restitution of GPS time with SA, to the level obtained without SA, focused on the implementation of a Kalman filter based on past data and updated at each new observation. An alternative solution relies upon the statistical features of the noise brought about by SA; it has already been shown that the SA noise is efficiently reduced by averaging data from numerous satellites observed simultaneously over a sufficiently long time. This method was successfully applied to data from a GPS time receiver, model AOA TTR-4P, connected to the cesium clock kept at the BIPM. This device, a multi-channel, dual frequency, P-code GPS time receiver, is one of the first TTR-4P units in operation in a civil laboratory. Preliminary comparative studies of this new equipment with conventional GPS time receivers are described in this paper. The results of an experimental restitution of GPS time, obtained in June 1993, are also detailed: 3 to 6 satellites were observed simultaneously with a sample interval of 15 s, an efficient smoothing of SA noise was realized by averaging data on all observed satellites over more than 1 hour. When the GPS system is complete in 1994, 8 satellites will be observable continuously from anywhere in the world and the same level of uncertainty will be obtained using a shorter averaging

Uporaba satelitskih sistemov GPS in GLONASS v geodetski izmeri

OpenAIRE

Oset, Klemen

2015-01-01

V geodetski izmeri GNSS se že nekaj časa za določanje položaja uporabljata hkrati sistema GLONASS in GPS. V diplomski nalogi sta predstavljena GNSS sistema GPS in GLONASS, podobnosti in razlike obeh sistemov ter njune značilnosti pri določitvi položaja. V praktičnem delu naloge so predstavljeni potek meritev, obdelava opazovanj in analiza kakovosti koordinat določenih na osnovi opazovanj GPS, opazovanj GLONASS in skupne uporabe opazovanj GPS in GLONASS.

Mining Significant Semantic Locations from GPS Data

DEFF Research Database (Denmark)

Cao, Xin; Cong, Gao; Jensen, Christian Søndergaard

2010-01-01

With the increasing deployment and use of GPS-enabled devices, massive amounts of GPS data are becoming available. We propose a general framework for the mining of semantically meaningful, significant locations, e.g., shopping malls and restaurants, from such data. We present techniques capable...... of extracting semantic locations from GPS data. We capture the relationships between locations and between locations and users with a graph. Significance is then assigned to locations using random walks over the graph that propagates significance among the locations. In doing so, mutual reinforcement between...

Arctic Tides from GPS on sea-ice

DEFF Research Database (Denmark)

Kildegaard Rose, Stine; Skourup, Henriette; Forsberg, René

2013-01-01

The presence of sea-ice in the Arctic Ocean plays a significant role in the Arctic climate. Sea-ice dampens the ocean tide amplitude with the result that global tidal models perform less accurately in the polar regions. This paper presents, a kinematic processing of global positioning system (GPS....... The results show coherence between the GPS buoy measurements, and the tide model. Furthermore, we have proved that the reference ellipsoid of WGS84, can be interpolated to the tidal defined zero level by applying geophysical corrections to the GPS data....

Mining significant semantic locations from GPS data

DEFF Research Database (Denmark)

Cao, Xin; Cong, Gao; Jensen, Christian S.

2010-01-01

With the increasing deployment and use of GPS-enabled devices, massive amounts of GPS data are becoming available. We propose a general framework for the mining of semantically meaningful, significant locations, e.g., shopping malls and restaurants, from such data. We present techniques capable...... of extracting semantic locations from GPS data. We capture the relationships between locations and between locations and users with a graph. Significance is then assigned to locations using random walks over the graph that propagates significance among the locations. In doing so, mutual reinforcement between...

Performance Analysis of Nomadic Mobile Services on Multi-homed Handheld Devices

NARCIS (Netherlands)

Pawar, P.; van Beijnum, Bernhard J.F.; van Sinderen, Marten J.; Aggarwal, Akshai; De Clercq, Frederic

2007-01-01

Compared to their predecessors, the current generation handheld mobile devices possess higher processing power, increased memory and new multi-homing capabilities. These features combined with the widespread acceptance and use of these devices result in a situation where mobile devices are no longer

Precise Orbit Determination of GPS Satellites Using Phase Observables

Directory of Open Access Journals (Sweden)

Myung-Kook Jee

1997-12-01

Full Text Available The accuracy of user position by GPS is heavily dependent upon the accuracy of satellite position which is usually transmitted to GPS users in radio signals. The real-time satellite position information directly obtained from broadcast ephimerides has the accuracy of 3 x 10 meters which is very unsatisfactory to measure 100km baseline to the accuracy of less than a few mili-meters. There are globally at present seven orbit analysis centers capable of generating precise GPS ephimerides and their orbit quality is of the order of about 10cm. Therefore, precise orbit model and phase processing technique were reviewed and consequently precise GPS ephimerides were produced after processing the phase observables of 28 global GPS stations for 1 day. Initial 6 orbit parameters and 2 solar radiation coefficients were estimated using batch least square algorithm and the final results were compared with the orbit of IGS, the International GPS Service for Geodynamics.

How to use hand-held computers to evaluate wood drying.

Science.gov (United States)

Howard N. Rosen; Darrell S. Martin

1985-01-01

Techniques have been developed to evaluate end generate wood drying curves with hand-held computers (3-5K memory). Predictions of time to dry to a specific moisture content, drying rates, and other characteristics of wood drying curves can be made. The paper describes the development of programs and illustrates their use.

A novel fully integrated handheld gamma camera

International Nuclear Information System (INIS)

Massari, R.; Ucci, A.; Campisi, C.; Scopinaro, F.; Soluri, A.

2016-01-01

In this paper, we present an innovative, fully integrated handheld gamma camera, namely designed to gather in the same device the gamma ray detector with the display and the embedded computing system. The low power consumption allows the prototype to be battery operated. To be useful in radioguided surgery, an intraoperative gamma camera must be very easy to handle since it must be moved to find a suitable view. Consequently, we have developed the first prototype of a fully integrated, compact and lightweight gamma camera for radiopharmaceuticals fast imaging. The device can operate without cables across the sterile field, so it may be easily used in the operating theater for radioguided surgery. The prototype proposed consists of a Silicon Photomultiplier (SiPM) array coupled with a proprietary scintillation structure based on CsI(Tl) crystals. To read the SiPM output signals, we have developed a very low power readout electronics and a dedicated analog to digital conversion system. One of the most critical aspects we faced designing the prototype was the low power consumption, which is mandatory to develop a battery operated device. We have applied this detection device in the lymphoscintigraphy technique (sentinel lymph node mapping) comparing the results obtained with those of a commercial gamma camera (Philips SKYLight). The results obtained confirm a rapid response of the device and an adequate spatial resolution for the use in the scintigraphic imaging. This work confirms the feasibility of a small gamma camera with an integrated display. This device is designed for radioguided surgery and small organ imaging, but it could be easily combined into surgical navigation systems.

A novel fully integrated handheld gamma camera

Energy Technology Data Exchange (ETDEWEB)

Massari, R.; Ucci, A.; Campisi, C. [Biostructure and Bioimaging Institute (IBB), National Research Council of Italy (CNR), Rome (Italy); Scopinaro, F. [University of Rome “La Sapienza”, S. Andrea Hospital, Rome (Italy); Soluri, A., E-mail: alessandro.soluri@ibb.cnr.it [Biostructure and Bioimaging Institute (IBB), National Research Council of Italy (CNR), Rome (Italy)

2016-10-01

In this paper, we present an innovative, fully integrated handheld gamma camera, namely designed to gather in the same device the gamma ray detector with the display and the embedded computing system. The low power consumption allows the prototype to be battery operated. To be useful in radioguided surgery, an intraoperative gamma camera must be very easy to handle since it must be moved to find a suitable view. Consequently, we have developed the first prototype of a fully integrated, compact and lightweight gamma camera for radiopharmaceuticals fast imaging. The device can operate without cables across the sterile field, so it may be easily used in the operating theater for radioguided surgery. The prototype proposed consists of a Silicon Photomultiplier (SiPM) array coupled with a proprietary scintillation structure based on CsI(Tl) crystals. To read the SiPM output signals, we have developed a very low power readout electronics and a dedicated analog to digital conversion system. One of the most critical aspects we faced designing the prototype was the low power consumption, which is mandatory to develop a battery operated device. We have applied this detection device in the lymphoscintigraphy technique (sentinel lymph node mapping) comparing the results obtained with those of a commercial gamma camera (Philips SKYLight). The results obtained confirm a rapid response of the device and an adequate spatial resolution for the use in the scintigraphic imaging. This work confirms the feasibility of a small gamma camera with an integrated display. This device is designed for radioguided surgery and small organ imaging, but it could be easily combined into surgical navigation systems.

PDOP values for simulated GPS/Galileo positioning

DEFF Research Database (Denmark)

Cederholm, Jens Peter

2005-01-01

The paper illustrates satellite coverage and PDOP values for a simulated combined GPS/Galileo system. The designed GPS satellite constellation and the planned Galileo satellite constellation are presented. The combined system is simulated and the number of visible satellites and PDOP values...

Two laboratory methods for the calibration of GPS speed meters

International Nuclear Information System (INIS)

Bai, Yin; Sun, Qiao; Du, Lei; Yu, Mei; Bai, Jie

2015-01-01

The set-ups of two calibration systems are presented to investigate calibration methods of GPS speed meters. The GPS speed meter calibrated is a special type of high accuracy speed meter for vehicles which uses Doppler demodulation of GPS signals to calculate the measured speed of a moving target. Three experiments are performed: including simulated calibration, field-test signal replay calibration, and in-field test comparison with an optical speed meter. The experiments are conducted at specific speeds in the range of 40–180 km h −1 with the same GPS speed meter as the device under calibration. The evaluation of measurement results validates both methods for calibrating GPS speed meters. The relative deviations between the measurement results of the GPS-based high accuracy speed meter and those of the optical speed meter are analyzed, and the equivalent uncertainty of the comparison is evaluated. The comparison results justify the utilization of GPS speed meters as reference equipment if no fewer than seven satellites are available. This study contributes to the widespread use of GPS-based high accuracy speed meters as legal reference equipment in traffic speed metrology. (paper)

Combining GPS measurements and IRI model predictions

International Nuclear Information System (INIS)

Hernandez-Pajares, M.; Juan, J.M.; Sanz, J.; Bilitza, D.

2002-01-01

The free electrons distributed in the ionosphere (between one hundred and thousands of km in height) produce a frequency-dependent effect on Global Positioning System (GPS) signals: a delay in the pseudo-orange and an advance in the carrier phase. These effects are proportional to the columnar electron density between the satellite and receiver, i.e. the integrated electron density along the ray path. Global ionospheric TEC (total electron content) maps can be obtained with GPS data from a network of ground IGS (international GPS service) reference stations with an accuracy of few TEC units. The comparison with the TOPEX TEC, mainly measured over the oceans far from the IGS stations, shows a mean bias and standard deviation of about 2 and 5 TECUs respectively. The discrepancies between the STEC predictions and the observed values show an RMS typically below 5 TECUs (which also includes the alignment code noise). he existence of a growing database 2-hourly global TEC maps and with resolution of 5x2.5 degrees in longitude and latitude can be used to improve the IRI prediction capability of the TEC. When the IRI predictions and the GPS estimations are compared for a three month period around the Solar Maximum, they are in good agreement for middle latitudes. An over-determination of IRI TEC has been found at the extreme latitudes, the IRI predictions being, typically two times higher than the GPS estimations. Finally, local fits of the IRI model can be done by tuning the SSN from STEC GPS observations

Self reported involvement in emergency medicine among GPs in Norway.

Science.gov (United States)

Hjortdahl, Magnus; Zakariassen, Erik; Halvorsen, Peder A

2018-04-10

To examine general practitioners' (GPs') perception of their role in emergency medicine and participation in emergency services including ambulance call outs, and the characteristics of the GPs and casualty clinics associated with the GPs' involvement in emergency medicine. Cross-sectional online survey. General practice. General practitioners in Norway (n = 1002). Proportion of GPs perceiving that they have a large role in emergency medicine, regularly being on call, and the proportion of ambulance callouts with GP participation. Forty six percent of the GPs indicated that they play a large role in emergency medicine, 63 percent of the GPs were regularly on call, and 28 percent responded that they usually took part in ambulance call outs. Multivariable logistic regression analyses indicated that these outcomes were strongly associated with participation in multidisciplinary training. Furthermore, the main outcomes were associated with traits commonly seen at smaller casualty clinics such as those with an absence of nursing personnel and extra physicians, and based on the distance to the hospital. Our findings suggest that GPs play an important role in emergency medicine. Multidisciplinary team training may be important for their continued involvement in prehospital emergencies. Key Points   Health authorities and other stakeholders have raised concerns about general practitioner's (GPs) participation in emergency medicine, but few have studied opinions and perceptions among the GPs themselves.   • Norwegian GPs report playing a large role in emergency medicine, regularly being on call, and taking part in selected ambulance call outs.   • A higher proportion of GPs who took part in team training perceived themselves as playing a large role in emergency medicine, regularly being on call, and taking part in ambulance call outs.   • These outcomes were also associated with attributes commonly seen at smaller casualty clinics.

Mobile satellite communications in the 1990's

Science.gov (United States)

Singh, Jai

1992-07-01

The evolution of Inmarsat global services from a single market and single service of the 1980's to all of the key mobile markets and a wide range of new terminals and services in the 1990's is described. An overview of existing mobile satellite services, as well as new services under implementation for introduction in the near and longer term, including a handheld satellite phone (Inmarsat-P), is provided. The initiative taken by Inmarsat in the integration of its global mobile satellite services with global navigation capability derived from GPS (Global Positioning System) and the GLONASS (Russian GPS) navigation satellite systems and the provision of an international civil overlay for GPS/GLONASS integrity and augmentation is highlighted. To complete the overview of the development of mobile satellite services in the 1990's, the known national and regional mobile satellite system plans and the various recent proposals for both orbiting and geostationary satellite systems for proving handheld satellite phone and/or data messaging services are described.

Near real-time GPS applications for tsunami early warning systems

Directory of Open Access Journals (Sweden)

C. Falck

2010-02-01

Full Text Available GPS (Global Positioning System technology is widely used for positioning applications. Many of them have high requirements with respect to precision, reliability or fast product delivery, but usually not all at the same time as it is the case for early warning applications. The tasks for the GPS-based components within the GITEWS project (German Indonesian Tsunami Early Warning System, Rudloff et al., 2009 are to support the determination of sea levels (measured onshore and offshore and to detect co-seismic land mass displacements with the lowest possible latency (design goal: first reliable results after 5 min. The completed system was designed to fulfil these tasks in near real-time, rather than for scientific research requirements. The obtained data products (movements of GPS antennas are supporting the warning process in different ways. The measurements from GPS instruments on buoys allow the earliest possible detection or confirmation of tsunami waves on the ocean. Onshore GPS measurements are made collocated with tide gauges or seismological stations and give information about co-seismic land mass movements as recorded, e.g., during the great Sumatra-Andaman earthquake of 2004 (Subarya et al., 2006. This information is important to separate tsunami-caused sea height movements from apparent sea height changes at tide gauge locations (sensor station movement and also as additional information about earthquakes' mechanisms, as this is an essential information to predict a tsunami (Sobolev et al., 2007.

This article gives an end-to-end overview of the GITEWS GPS-component system, from the GPS sensors (GPS receiver with GPS antenna and auxiliary systems, either onshore or offshore to the early warning centre displays. We describe how the GPS sensors have been installed, how they are operated and the methods used to collect, transfer and process the GPS data in near real-time. This includes the sensor system design, the communication

Convective towers detection using GPS radio occultations

DEFF Research Database (Denmark)

Biondi, Riccardo; Neubert, Torsten; Syndergaard, S.

the GPS signals penetrate through clouds and allow measurements of atmospheric profiles related to temperature, pressure, and water vapour with high vertical resolution. Using tropical cyclone best track database and data from different GPS RO missions (COSMIC, GRACE, CHAMP, SACC and GPSMET), we selected...

Integrating GIS and GPS in environmental remediation oversight

International Nuclear Information System (INIS)

Kaletsky, K.; Earle, J.R.; Schneider, T.A.

1996-01-01

This paper presents findings on Ohio EPA Office of Federal Facilities Oversight's (OFFO) use of GIS and GPS for environmental remediation oversight at the U.S. Department of Energy's (DOE) Fernald Site. The Fernald site is a former uranium metal production facility within DOE's nuclear weapons complex. Significant uranium contamination of soil and groundwater is being remediated under state and federal regulations. OFFO uses GIS/GPS to enhance environmental monitoring and remediation oversight. These technologies are utilized within OFFO's environmental monitoring program for sample location and parameter selection, data interpretation and presentation. GPS is used to integrate sample data into OFFO's GIS and for permanently linking precise and accurate geographic data to samples and waste units. It is important to identify contamination geographically as all visual references (e.g., buildings, infrastructure) will be removed during remediation. Availability of the GIS allows OFFO to perform independent analysis and review of DOE contractor generated data, models, maps, and designs. This ability helps alleviate concerns associated with open-quotes black boxclose quotes models and data interpretation. OFFO's independent analysis has increased regulatory confidence and the efficiency of design reviews. GIS/GPS technology allows OFFO to record and present complex data in a visual format aiding in stakeholder education and awareness. Presented are OFFO's achievements within the aforementioned activities and some reasons learned in implementing the GIS/GPS program. OFFO's two years of GIS/GPS development have resulted in numerous lessons learned and ideas for increasing effectiveness through the use of GIS/GPS

77 FR 23668 - GPS Satellite Simulator Working Group Notice of Meeting

Science.gov (United States)

2012-04-20

... DEPARTMENT OF DEFENSE Department of the Air Force GPS Satellite Simulator Working Group Notice of... inform the public that the Global Positioning Systems (GPS) Directorate will be hosting an open GPS Satellite Simulator Working Group (SSWG) meeting for manufacturers of GPS constellation simulators utilized...

A low-power CMOS frequency synthesizer for GPS receivers

International Nuclear Information System (INIS)

Yu Yunfeng; Xiao Shimao; Zhuang Haixiao; Ma Chengyan; Ye Tianchun; Yue Jianlian

2010-01-01

A low-power frequency synthesizer for GPS/Galileo L1/E1 band receivers implemented in a 0.18 μm CMOS process is introduced. By adding clock-controlled transistors at latch outputs to reduce the time constant at sensing time, the working frequency of the high-speed source-coupled logic prescaler supplying quadrature local oscillator signals has been increased, compared with traditional prescalers. Measurement results show that this synthesizer achieves an in-band phase noise of -87 dBc/Hz at 15 kHz offset, with spurs less than -65 dBc. The whole synthesizer consumes 6 mA in the case of a 1.8 V supply, and its core area is 0.6 mm 2 . (semiconductor integrated circuits)

Accuracy assessment of high-rate GPS measurements for seismology

Science.gov (United States)

Elosegui, P.; Davis, J. L.; Ekström, G.

2007-12-01

Analysis of GPS measurements with a controlled laboratory system, built to simulate the ground motions caused by tectonic earthquakes and other transient geophysical signals such as glacial earthquakes, enables us to assess the technique of high-rate GPS. The root-mean-square (rms) position error of this system when undergoing realistic simulated seismic motions is 0.05~mm, with maximum position errors of 0.1~mm, thus providing "ground truth" GPS displacements. We have acquired an extensive set of high-rate GPS measurements while inducing seismic motions on a GPS antenna mounted on this system with a temporal spectrum similar to real seismic events. We found that, for a particular 15-min-long test event, the rms error of the 1-Hz GPS position estimates was 2.5~mm, with maximum position errors of 10~mm, and the error spectrum of the GPS estimates was approximately flicker noise. These results may however represent a best-case scenario since they were obtained over a short (~10~m) baseline, thereby greatly mitigating baseline-dependent errors, and when the number and distribution of satellites on the sky was good. For example, we have determined that the rms error can increase by a factor of 2--3 as the GPS constellation changes throughout the day, with an average value of 3.5~mm for eight identical, hourly-spaced, consecutive test events. The rms error also increases with increasing baseline, as one would expect, with an average rms error for a ~1400~km baseline of 9~mm. We will present an assessment of the accuracy of high-rate GPS based on these measurements, discuss the implications of this study for seismology, and describe new applications in glaciology.

GPS-based satellite tracking system for precise positioning

Science.gov (United States)

Yunck, T. P.; Melbourne, W. G.; Thornton, C. L.

1985-01-01

NASA is developing a Global Positioning System (GPS) based measurement system to provide precise determination of earth satellite orbits, geodetic baselines, ionospheric electron content, and clock offsets between worldwide tracking sites. The system will employ variations on the differential GPS observing technique and will use a network of nine fixed ground terminals. Satellite applications will require either a GPS flight receiver or an on-board GPS beacon. Operation of the system for all but satellite tracking will begin by 1988. The first major satellite application will be a demonstration of decimeter accuracy in determining the altitude of TOPEX in the early 1990's. By then the system is expected to yield long-baseline accuracies of a few centimeters and instantaneous time synchronization to 1 ns.

Why do GPs leave direct patient care and what might help to retain them? A qualitative study of GPs in South West England.

Science.gov (United States)

Sansom, Anna; Terry, Rohini; Fletcher, Emily; Salisbury, Chris; Long, Linda; Richards, Suzanne H; Aylward, Alex; Welsman, Jo; Sims, Laura; Campbell, John L; Dean, Sarah G

2018-01-10

To identify factors influencing general practitioners' (GPs') decisions about whether or not to remain in direct patient care in general practice and what might help to retain them in that role. Qualitative, in-depth, individual interviews exploring factors related to GPs leaving, remaining in and returning to direct patient care. South West England, UK. 41 GPs: 7 retired; 8 intending to take early retirement; 11 who were on or intending to take a career break; 9 aged under 50 years who had left or were intending to leave direct patient care and 6 who were not intending to leave or to take a career break. Plus 19 stakeholders from a range of primary care-related professional organisations and roles. Reasons for leaving direct patient care were complex and based on a range of job-related and individual factors. Three key themes underpinned the interviewed GPs' thinking and rationale: issues relating to their personal and professional identity and the perceived value of general practice-based care within the healthcare system; concerns regarding fear and risk, for example, in respect of medical litigation and managing administrative challenges within the context of increasingly complex care pathways and environments; and issues around choice and volition in respect of personal social, financial, domestic and professional considerations. These themes provide increased understanding of the lived experiences of working in today's National Health Service for this group of GPs. Future policies and strategies aimed at retaining GPs in direct patient care should clarify the role and expectations of general practice and align with GPs' perception of their own roles and identity; demonstrate to GPs that they are valued and listened to in planning delivery of the UK healthcare; target GPs' concerns regarding fear and risk, seeking to reduce these to manageable levels and give GPs viable options to support them to remain in direct patient care. © Article author(s) (or their

Present coupling along the Peruvian subduction asperity that devastated Lima while breaking during the 1746 earthquake

Science.gov (United States)

Cavalié, O.; Chlieh, M.; Villegas Lanza, J. C.

2017-12-01

Subduction zone are particularly prone to generating large earthquakes due to its wide lateral extension. In order to understand where, and possibly when, large earthquakes will occur, interseismic deformation observation is a key information because it allows to map asperities that accumulate stress on the plate interface. South American subduction is one of the longest worldwide, running all along the west coast of the continent. Combined with the relatively fast convergence rate between the Nazca plate and the South American continent, Chile and Peru experience regularly M>7.5 earthquakes. In this study, we focused on the Peruvian subduction margin and more precisely on the Central segment containing Lima where the seismic risk is the highest in the country due the large population that lives in the Peruvian capital. On the Central segment (10°S and 15°S), we used over 50 GPS interseismic measurements from campaign and continuous sites, as well as InSAR data to map coupling along the subduction interface. GPS data come from the Peruvian GPS network and InSAR data are from the Envisat satellite. We selected two tracks covering the central segment (including Lima) and with enough SAR image acquisitions between 2003 and 2010 to get a robust deformation estimation. GPS and InSAR data show a consistent tectonic signal with a maximum of surface displacement by the coast: the maximum horizontal velocities from GPS is about 20 mm and InSAR finds 12-13 mm in the LOS component. In addition, InSAR reveals lateral variations along the coast: the maximum motion is measured around Lima (11°S) and fades on either side. By inverting the geodetic data, we were able to map the coupling along the segment. It results in a main asperity where interseismic stress is loading. However, compared the previous published models based on GPS only, the coupling in the central segment seems more heterogeneous. Finally, we compared the deficit of seismic moment accumulating in the

Fundamentals of GPS Receivers A Hardware Approach

CERN Document Server

Doberstein, Dan

2012-01-01

While much of the current literature on GPS receivers is aimed at those intimately familiar with their workings, this volume summarizes the basic principles using as little mathematics as possible, and details the necessary specifications and circuits for constructing a GPS receiver that is accurate to within 300 meters. Dedicated sections deal with the features of the GPS signal and its data stream, the details of the receiver (using a hybrid design as exemplar), and more advanced receivers and topics including time and frequency measurements. Later segments discuss the Zarlink GPS receiver chip set, as well as providing a thorough examination of the TurboRogue receiver, one of the most accurate yet made. Guiding the reader through the concepts and circuitry, from the antenna to the solution of user position, the book’s deployment of a hybrid receiver as a basis for discussion allows for extrapolation of the core ideas to more complex, and more accurate designs. Digital methods are used, but any analogue c...

Exploring female GPs' perceptions about medical leadership.

Science.gov (United States)

Price, Karen; Clearihan, Lynette

2015-06-01

Women are increasingly entering the Australian general practice workforce. This study aims to explore female general practitioners' (GPs') perceptions of possible barriers to leadership and professional roles in the workforce. A purposive, convenience sample of 30 female GPs in active practice was approached in February, 2012. An anonymous, pa-per-based, semi-quantitative survey sought to identify participation and leadership confidence within general practice in a number of professional roles. The top two barriers participants identified for after-hours medical meetings were energy to attend and geographical location. For after-hours care, the top two barriers identified were energy and self-motivation. Few participants aspired to 'leadership' activities. 'Medical mentoring' was most likely to attract them into leadership. It is important female GPs' perspectives are explored in general practice. This small survey suggests further studies are needed in the importance of energy limitations and lack of self-confidence in restricting female GPs' capacity to fully engage in professional roles.

GPS Receivers Use-Case Information : GPS Adjacent Band Compatibility Assessment Workshop

Science.gov (United States)

2014-09-18

Topics 1. Background. 2. Use Case Template. 3. Description of Submitted UseCases from DOT Extended Pos/Nav Working Group. 4. Utilization of UseCase Information. 5. Request of Information for Additional UseCases from GPS Receiver Manufacturer...

Forearc Sliver Translation, a Lack of Arc-Normal Strain Accumulation, and Interplate Thrust Earthquakes: GPS Geodesy in Western Nicaragua

Science.gov (United States)

Turner, H. L.; Mattioli, G. S.; Jansma, P. E.; Styron, R. H.

2007-05-01

We have been investigating the kinematics of the Nicaraguan forearc using campaign GPS measurements of our geodetic network made over the last seven years (Turner et al., 2007). We currently have interseismic velocities for 18 campaign sites and have installed 10 additional sites in the backarc to investigate the nature of the transition from forearc sliver motion to stable Caribbean Plate motion. Our work focusing on the later issue is presented elsewhere at this meeting (Styron et al., 2007). Corrections for modeled coseismic offsets from the Jan. 13, 2001 Mw7.7 earthquake off the coast of El Salvador have been applied to our campaign site velocities. Some of our time-series are also strongly affected by coseismic and postseismic effects of the Oct. 9, 2004 Mw6.9 earthquake off of the coast of Nicaragua. The geodetic effects of this event are being removed from the affected time-series for interseismic velocity analysis. We have also derived interseismic velocities for five continuous GPS sites in the region. Our GPS results confirm previous predictions of northwest transport of a forearc sliver with an average Northwest velocity of ~15 mm yr-1, but show little evidence for an arc- normal component of strain accumulation associated with locking on the subduction interface. However, the amount of seismicity along this section of the Middle America Trench, including several recent large events such as the 1992 Mw7.6 and 2004 Mw6.9 earthquakes, indicates some amount of locking is present. Several possibilities may account for the apparent contradiction between the GPS results and observed seismicity. The locked zone may be too shallow and too far offshore for the arc-normal component to show up in our network, or the arc-normal signal may be masked by post-seismic effects from the 1992 offshore earthquake. If coupling between the downgoing slab and the overriding plate is weak or limited to a small seismogenic zone, then arc-parallel motion of the forearc sliver may

The Weak Link HP-41C hand-held calculator program

Science.gov (United States)

Ross A. Phillips; Penn A. Peters; Gary D. Falk

1982-01-01

The Weak Link hand-held calculator program (HP-41C) quickly analyzes a system for logging production and costs. The production equations model conventional chain saw, skidder, loader, and tandemaxle truck operations in eastern mountain areas. Production of each function of the logging system may be determined so that the system may be balanced for minimum cost. The...

Standardization from a benchtop to a handheld NIR spectrometer using mathematically mixed NIR spectra to determine fuel quality parameters

DEFF Research Database (Denmark)

da Silva, Neirivaldo Cavalcante; Cavalcanti, Claudia Jessica; Honorato, Fernanda Araujo

2017-01-01

spectral responses of fuel samples (gasoline and biodiesel blends) from a high-resolution benchtop Frontier FT-NIR (PerkinElmer) spectrometer and a handheld MicroNIR™1700 (JDSU). These virtual standards can be created by mathematically mixing spectra from the pure solvents present in gasoline or diesel...... to the handheld MicroNIR using virtual standards as transfer samples...

Earth tide effects on kinematic/static GPS positioning in Denmark and Greenland

DEFF Research Database (Denmark)

Xu, G.C.; Knudsen, Per

2000-01-01

A detailed Study of the Earth tide effects on the GPS kinematic/static positioning is presented in this paper by using theoretical Earth tide computation and practical GPS data processing. Tidal effects could reach up to 30 cm in Denmark and Greenland depending on the measuring time...... and the position of reference station. With a baseline less than 80 km, the difference of the Earth tide effects could reach more than 5 mm. So, in precise applications of GPS positioning, the Earth tide effect has to be taken into account even for a relative small local GPS network. Several examples are given...... for demonstrating that the Earth tide effects can be viewed by GPS surveying. They are given through static GPS data static processing, static GPS data kinematic processing, and airborne kinematic GPS data processing. In these cases, the Earth tide effects can be subtracted from the GPS results. The determination...

GPS test range mission planning

Science.gov (United States)

Roberts, Iris P.; Hancock, Thomas P.

The principal features of the Test Range User Mission Planner (TRUMP), a PC-resident tool designed to aid in deploying and utilizing GPS-based test range assets, are reviewed. TRUMP features time history plots of time-space-position information (TSPI); performance based on a dynamic GPS/inertial system simulation; time history plots of TSPI data link connectivity; digital terrain elevation data maps with user-defined cultural features; and two-dimensional coverage plots of ground-based test range assets. Some functions to be added during the next development phase are discussed.

Development of dual sensor hand-held detector

Science.gov (United States)

Sezgin, Mehmet

2010-04-01

In this paper hand-held dual sensor detector development requirements are considered dedicated to buried object detection. Design characteristics of such a system are categorized and listed. Hardware and software structures, ergonomics, user interface, environmental and EMC/EMI tests to be applied and performance test issues are studied. Main properties of the developed system (SEZER) are presented, which contains Metal Detector (MD) and Ground Penetrating Radar (GPR). The realized system has ergonomic structure and can detect both metallic and non-metallic buried objects. Moreover classification of target is possible if it was defined to the signal processing software in learning phase.

Reusable Handheld Electrolytes and Lab Technology for Humans (rHEALTH Sensor), Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The goal of rHEALTH sensor is a universal handheld sensor that can provide rapid, low-cost complete blood count (CBC) with differential, electrolyte analysis, and...

Reusable Handheld Electrolytes and Lab Technology for Humans (rHEALTH Sensor), Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The goal of the rHEALTH sensor is to provide rapid, low-cost, handheld complete blood count (CBC), cell differential counts, electrolyte measurements, and other lab...

GPS Attitude Determination for Launch Vehicles, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Toyon Research Corporation proposes to develop a family of compact, low-cost GPS-based attitude (GPS/A) sensors for launch vehicles. In order to obtain 3-D attitude...

Application and Limitations of GPS Radio Occultation (GPS-RO) Data for Atmospheric Boundary Layer Height Detection over the Arctic.

Science.gov (United States)

Ganeshan, M.; Wu, D. L.

2014-12-01

Due to recent changes in the Arctic environment, it is important to monitor the atmospheric boundary layer (ABL) properties over the Arctic Ocean, especially to explore the variability in ABL clouds (such as sensitivity and feedback to sea ice loss). For example, radiosonde and satellite observations of the Arctic ABL height (and low-cloud cover) have recently suggested a positive response to sea ice loss during October that may not occur during the melt season (June-September). Owing to its high vertical and spatiotemporal resolution, an independent ABL height detection algorithm using GPS Radio Occultation (GPS-RO) refractivity in the Arctic is explored. Similar GPS-RO algorithms developed previously typically define the level of the most negative moisture gradient as the ABL height. This definition is favorable for subtropical oceans where a stratocumulus-topped ABL is often capped by a layer of sharp moisture lapse rate (coincident with the temperature inversion). The Arctic Ocean is also characterized by stratocumulus cloud cover, however, the specific humidity does not frequently decrease in the ABL capping inversion. The use of GPS-RO refractivity for ABL height retrieval therefore becomes more complex. During winter months (December-February), when the total precipitable water in the troposphere is a minimum, a fairly straightforward algorithm for ABL height retrieval is developed. The applicability and limitations of this method for other seasons (Spring, Summer, Fall) is determined. The seasonal, interannual and spatial variability in the GPS-derived ABL height over the Arctic Ocean, as well as its relation to the underlying surface (ice vs. water), is investigated. The GPS-RO profiles are also explored for the evidence of low-level moisture transport in the cold Arctic environment.

Penerapan Teknologi GPS Tracker Untuk Identifikasi Kondisi Traffik Jalan Raya

Directory of Open Access Journals (Sweden)

IM. O. Widyantara

2015-06-01

Full Text Available Real time tracking system technology has been made possible by integrating three technologies, namely global positioning system (GPS, database technologies such as geographic information system (GIS and mobile telecommunications technologies such as general packet radio service (GPRS. This paper has proposed a vehicle tracking mechanism based on GPS tracker to build a real-time traffic information system. A GPS server is built to process data of position and speed of the vehicle for further processed into vehicle traffic information. The Server and GPS tracker is designed to communicate using GPRS services in real time. Furthermore, the server processes the data from the GPS tracker into traffic information such as traffic jam, dense, medium and smoothly. Test results showed that the GPS server is able to visualize the real position of the vehicle and is able to decide the category of traffic information in real time.

GPs' mental wellbeing and psychological resources: a cross-sectional survey.

Science.gov (United States)

Murray, Marylou Anna; Cardwell, Chris; Donnelly, Michael

2017-08-01

The negative impact of work has been the traditional focus of GP surveys. We know little about GP positive mental health and psychological resources. To profile and contextualise GP positive mental health and personal psychological resources. Cross-sectional survey of GPs working in Northern Ireland (NI). A questionnaire comprising the Warwick Edinburgh Mental Wellbeing Scale (WEMWBS) and measures of resilience, optimism, self-efficacy, and hope, and sociodemographic information was posted to 400 GPs randomly selected from a publicly available GP register. The response rate was 55% (n = 221 out of 400). Mean value for GP wellbeing (WEMWBS) was 50.2 (standard deviation [SD] 8) compared to UK vets 48.8 (SD 9), UK teachers 47.2 (SD 9), and the population of NI 50.8 (SD 9). After adjustment for confounding, mean WEMWBS was 2.4 units (95% CI = 0.02 to 4.7) higher in female GPs than males ( P = 0.05), and 4.0 units (95% CI = 0.8 to 7.3) higher in GPs ≥55 years than GPs ≤44 years ( P = 0.02). Optimism was 1.1 units higher in female GPs than male GPs (95% CI = 0.1 to 2.0), and 1.56 units higher in GPs ≥55 years (95% CI = 0.2 to 2.9) than in those ≤44 years. Hope was 3 units higher in GPs ≥55 years (95% CI = 0.4 to 5.7) than in those aged 45-54 years. Correlation between WEMWBS and psychological resources was highest with hope ( r = 0.65, P mental health that are comparable to the local population and better than other occupational groups, such as vets and teachers. Male and younger GPs may have most to gain from wellbeing interventions. © British Journal of General Practice 2017.

77 FR 70421 - GPS Satellite Simulator Control Working Group Meeting

Science.gov (United States)

2012-11-26

... DEPARTMENT OF DEFENSE Department of the Air Force GPS Satellite Simulator Control Working Group Meeting AGENCY: Space and Missile Systems Center, Global Positioning Systems (GPS) Directorate, Department of the Air Force, DoD. ACTION: Meeting Notice. SUMMARY: This meeting notice is to inform GPS...

Outcome prediction in gastroschisis - The gastroschisis prognostic score (GPS) revisited.

Science.gov (United States)

Puligandla, Pramod S; Baird, Robert; Skarsgard, Eric D; Emil, Sherif; Laberge, Jean-Martin

2017-05-01

The GPS enables risk stratification for gastroschisis and helps discriminate low from high morbidity groups. The purpose of this study was to revalidate GPS's characterization of a high morbidity group and to quantify relationships between the GPS and outcomes. With REB approval, complete survivor data from a national gastroschisis registry was collected. GPS bowel injury scoring was revalidated excluding the initial inception/validation cohorts (>2011). Length of stay (LOS), 1st enteral feed days (dFPO), TPN days (dTPN), and aggregate complications (COMP) were compared between low and high morbidity risk groups. Mathematical relationships between outcomes and integer increases in GPS were explored using the entire cohort (2005-present). Median (range) LOS, dPO, and dTPN for the entire cohort (n=849) was 36 (26,62), 13 (9,18), and 27 (20,46) days, respectively. High-risk patients (GPS≥2; n=80) experienced significantly worse outcomes than low risk patients (n=263). Each integer increase in GPS was associated with increases in LOS and dTPN by 16.9 and 12.7days, respectively (pGPS effectively discriminates low from high morbidity risk groups. Within the high risk group, integer increases in GPS produce quantitatively differentiated outcomes which may guide initial counseling and resource allocation. IIb. Copyright © 2017 Elsevier Inc. All rights reserved.

Ionospheric Scintillation Effects on GPS

Science.gov (United States)

Steenburgh, R. A.; Smithtro, C.; Groves, K.

2007-12-01

. Ionospheric scintillation of Global Positioning System (GPS) signals threatens navigation and military operations by degrading performance or making GPS unavailable. Scintillation is particularly active, although not limited to, a belt encircling the earth within 20 degrees of the geomagnetic equator. As GPS applications and users increases, so does the potential for detrimental impacts from scintillation. We examined amplitude scintillation data spanning seven years from Ascension Island, U.K.; Ancon, Peru; and Antofagasta, Chile in the Atlantic/Americas longitudinal sector at as well as data from Parepare, Indonesia; Marak Parak, Malaysia; Pontianak, Indonesia; Guam; and Diego Garcia, U.K.; in the Pacific longitudinal sector. From these data, we calculate percent probability of occurrence of scintillation at various intensities described by the S4 index. Additionally, we determine Dilution of Precision at one minute resolution. We examine diurnal, seasonal and solar cycle characteristics and make spatial comparisons. In general, activity was greatest during the equinoxes and solar maximum, although scintillation at Antofagasta, Chile was higher during 1998 rather than at solar maximum.

PROSPECTIVE EVALUATION OF VISUAL ACUITY AGREEMENT BETWEEN STANDARD EARLY TREATMENT DIABETIC RETINOPATHY STUDY CHART AND A HANDHELD EQUIVALENT IN EYES WITH RETINAL PATHOLOGY.

Science.gov (United States)

Rahimy, Ehsan; Reddy, Sahitya; DeCroos, Francis Char; Khan, M Ali; Boyer, David S; Gupta, Omesh P; Regillo, Carl D; Haller, Julia A

2015-08-01

To evaluate the visual acuity agreement between a standard back-illuminated Early Treatment Diabetic Retinopathy Study (ETDRS) chart and a handheld internally illuminated ETDRS chart. Two-center prospective study. Seventy patients (134 eyes) with retinal pathology were enrolled between October 2012 and August 2013. Visual acuity was measured using both the ETDRS chart and the handheld device by masked independent examiners after best protocol refraction. Examination was performed in the same room under identical illumination and testing conditions. The mean number of letters seen was 63.0 (standard deviation: 19.8 letters) and 61.2 letters (standard deviation: 19.1 letters) for the ETDRS chart and handheld device, respectively. Mean difference per eye between the ETDRS and handheld device was 1.8 letters. A correlation coefficient (r) of 0.95 demonstrated a positive linear correlation between ETDRS chart and handheld device measured acuities. Intraclass correlation coefficient was performed to assess the reproducibility of the measurements made by different observers measuring the same quantity and was calculated to be 0.95 (95% confidence interval: 0.93-0.96). Agreement was independent of retinal disease. The strong correlation between measured visual acuity using the ETDRS and handheld equivalent suggests that they may be used interchangeably, with accurate measurements. Potential benefits of this device include convenience and portability, as well as the ability to assess ETDRS visual acuity without a dedicated testing lane.

Understanding quit decisions in primary care: a qualitative study of older GPs.

Science.gov (United States)

Sansom, Anna; Calitri, Raff; Carter, Mary; Campbell, John

2016-02-19

To investigate the reasons behind intentions to quit direct patient care among experienced general practitioners (GPs) aged 50-60 years. Qualitative study based on semistructured interviews with GPs in the South West region of England. Transcribed interviews were analysed thematically. 23 GPs aged 50-60 years: 3 who had retired from direct patient care before age 60, and 20 who intended to quit direct patient care within the next 5 years. The analysis identified four key themes: early retirement is a viable option for many GPs; GPs have employment options other than undertaking direct patient care; GPs report feeling they are doing an (almost) undoable job; and GPs may have other aspirations that pull them away from practice. Findings from this study confirmed those from earlier research, with high workload, ageing and health, family and domestic life, and organisational change all influencing GPs' decisions about when to retire/quit direct patient care. However, in addition, GPs expressed feelings of insecurity and uncertainty regarding the future of general practice, low morale, and issues regarding accountability (appraisal and revalidation) and governance. Suggestions about how to help retain GPs within the active clinical workforce were offered, covering individual, practice and organisational levels. This research highlights aspects of the current professional climate for GPs that are having an impact on retirement decisions. Any future changes to policy or practice to help retain experienced GPs will benefit from this informed understanding of GPs' views. Key factors to take into account include: making the GP workload more manageable; managing change sympathetically; paying attention to GPs' own health; improving confidence in the future of general practice; and improving GP morale. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

GPS Navigation Above 76,000 km for the MMS Mission

Science.gov (United States)

Winternitz, Luke; Bamford, Bill; Price, Samuel; Long, Anne; Farahmand, Mitra; Carpenter, Russell

2016-01-01

NASA's MMS mission, launched in March of 2015,consists of a controlled formation of four spin-stabilized spacecraft in similar highly elliptic orbits reaching apogee at radial distances of 12and 25 Earth radii in the first and second phases of the mission. Navigation for MMS is achieved independently onboard each spacecraft by processing GPS observables using NASA GSFC's Navigator GPS receiver and the Goddard Enhanced Onboard Navigation System (GEONS) extended Kalman filter software. To our knowledge, MMS constitutes, by far, the highest-altitude operational use of GPS to date and represents the culmination of over a decade of high-altitude GPS navigation research and development at NASA GSFC. In this paper we will briefly describe past and ongoing high-altitude GPS research efforts at NASA GSFC and elsewhere, provide details on the design of the MMS GPS navigation system, and present on-orbit performance data. We extrapolate these results to predict performance in the Phase 2b mission orbit, and conclude with a discussion of the implications of the MMS results for future high-altitude GPS navigation, which we believe to be broad and far-reaching.

Nowcasting the lightning activity in Peninsular Malaysia using the GPS PWV during the 2009 inter-monsoons

Directory of Open Access Journals (Sweden)

Wayan Suparta

2014-05-01

Full Text Available The spatial and temporal radio wave delay of the Global Positioning System (GPS signal can be manipulated to estimate the precipitable water vapor (PWV which favorable for meteorological applications. A rapid change of the water vapor amount was a precondition for the unbalanced atmospheric charges, which noticeably associated with the development of convective cloud as a lightning chamber. According to this fact, GPS derived PWV will be utilized to nowcasting the lightning event for the next couple of hours. The variances of PWV of four-selected station of the Peninsular Malaysia during the past two inter-monsoons events in May and November 2009 were analyzed. To clarify the response, the changes of PWV in hourly Δ (max-min before the lightning event was investigated with minimum value 2 mm and is maintained at least three consecutive hours. There are 177 samples were extracted from this method and 69% of the sample showed the lightning occurrence with an average duration was after the six consecutive hours. The lightning day with 2 mm Δ was also higher than the fair weather of 6.3%. These findings suggest that the GPS data can be proposed further as a guide to nowcast the occurrence of lightning activity.

Gen-2 Hand-Held Optical Imager towards Cancer Imaging: Reflectance and Transillumination Phantom Studies

Directory of Open Access Journals (Sweden)

Anuradha Godavarty

2012-02-01

Full Text Available Hand-held near-infrared (NIR optical imagers are developed by various researchers towards non-invasive clinical breast imaging. Unlike these existing imagers that can perform only reflectance imaging, a generation-2 (Gen-2 hand-held optical imager has been recently developed to perform both reflectance and transillumination imaging. The unique forked design of the hand-held probe head(s allows for reflectance imaging (as in ultrasound and transillumination or compressed imaging (as in X-ray mammography. Phantom studies were performed to demonstrate two-dimensional (2D target detection via reflectance and transillumination imaging at various target depths (1–5 cm deep and using simultaneous multiple point illumination approach. It was observed that 0.45 cc targets were detected up to 5 cm deep during transillumination, but limited to 2.5 cm deep during reflectance imaging. Additionally, implementing appropriate data post-processing techniques along with a polynomial fitting approach, to plot 2D surface contours of the detected signal, yields distinct target detectability and localization. The ability of the gen-2 imager to perform both reflectance and transillumination imaging allows its direct comparison to ultrasound and X-ray mammography results, respectively, in future clinical breast imaging studies.

The reliability and validity of hand-held refractometry water content measures of hydrogel lenses.

Science.gov (United States)

Nichols, Jason J; Mitchell, G Lynn; Good, Gregory W

2003-06-01

To investigate within- and between-examiner reliability and validity of hand-held refractometry water content measures of hydrogel lenses. Nineteen lenses of various nominal water contents were examined by two examiners on two occasions separated by 1 hour. An Atago N2 hand-held refractometer was used for all water content measures. Lenses were presented in a random order to each examiner by a third party, and examiners were masked to any potential lens identifiers. Intraclass correlation coefficients (ICC), 95% limits of agreement, and Wilcoxon signed rank test were used to characterize the within- and between-examiner reliability and validity of lens water content measures. Within-examiner reliability was excellent (ICC, 0.97; 95% limits of agreement, -3.6% to +5.7%), and the inter-visit mean difference of 1.1 +/- 2.4% was not biased (p = 0.08). Between-examiner reliability was also excellent (ICC, 0.98; 95% limits of agreement, -4.1% to +3.9%). The mean difference between examiners was -0.1 +/- 2.1% (p = 0.83). The mean difference between the nominally reported water content and our water content measures was -2.1 +/- 1.7% (p refractometry and is material dependent. Therefore, investigators may need to account for bias when measuring hydrogel lens water content via hand-held refractometry.

En Billig GPS Data Analyse Platform

DEFF Research Database (Denmark)

Andersen, Ove; Christiansen, Nick; Larsen, Niels T.

2011-01-01

Denne artikel præsenterer en komplet software platform til analyse af GPS data. Platformen er bygget udelukkende vha. open-source komponenter. De enkelte komponenter i platformen beskrives i detaljer. Fordele og ulemper ved at bruge open-source diskuteres herunder hvilke IT politiske tiltage, der...... organisationer med et digitalt vejkort og GPS data begynde at lave trafikanalyser på disse data. Det er et krav, at der er passende IT kompetencer tilstede i organisationen....

78 FR 63459 - GPS Satellite Simulator Control Working Group Meeting

Science.gov (United States)

2013-10-24

... DEPARTMENT OF DEFENSE Air Force GPS Satellite Simulator Control Working Group Meeting AGENCY: Department of the Air Force. ACTION: Meeting Notice. SUMMARY: This meeting notice is to inform GPS simulator manufacturers, who supply products to the Department of Defense (DoD), and GPS simulator users, both government...

Sensing and Classifying Impairments of GPS Reception on Mobile Devices

DEFF Research Database (Denmark)

Blunck, Henrik; Kjærgaard, Mikkel Baun; Toftegaard, Thomas Skjødeberg

2011-01-01

Positioning using GPS receivers is a primary sensing modality in many areas of pervasive computing. However, previous work has not considered how people’s body impacts the availability and accuracy of GPS positioning and for means to sense such impacts. We present results that the GPS performance...

GPs' perceptions of resilience training: a qualitative study.

Science.gov (United States)

Cheshire, Anna; Hughes, John; Lewith, George; Panagioti, Maria; Peters, David; Simon, Chantal; Ridge, Damien

2017-10-01

GPs are reporting increasing levels of burnout, stress, and job dissatisfaction, and there is a looming GP shortage. Promoting resilience is a key strategy for enhancing the sustainability of the healthcare workforce and improving patient care. To explore GPs' perspectives on the content, context, and acceptability of resilience training programmes in general practice, in order to build more effective GP resilience programmes. This was a qualitative study of the perspectives of GPs currently practising in England. GPs were recruited through convenience sampling, and data were collected from two focus groups ( n = 15) and one-to-one telephone interviews ( n = 7). A semi-structured interview approach was used and data were analysed using thematic analysis. Participants perceived resilience training to be potentially of value in ameliorating workplace stresses. Nevertheless, uncertainty was expressed regarding how best to provide training for stressed GPs who have limited time. Participants suspected that GPs most likely to benefit from resilience training were the least likely to engage, as stress and being busy worked against engagement. Conflicting views were expressed about the most suitable training delivery method for promoting better engagement. Participants also emphasised that training should not only place the focus on the individual, but also focus on organisation issues. A multimodal, flexible approach based on individual needs and learning aims, including resilience workshops within undergraduate training and in individual practices, is likely to be the optimal way to promote resilience. © British Journal of General Practice 2017.

Hand-held transendoscopic robotic manipulators: A transurethral laser prostate surgery case study.

Science.gov (United States)

Hendrick, Richard J; Mitchell, Christopher R; Herrell, S Duke; Webster, Robert J

2015-11-01

Natural orifice endoscopic surgery can enable incisionless approaches, but a major challenge is the lack of small and dexterous instrumentation. Surgical robots have the potential to meet this need yet often disrupt the clinical workflow. Hand-held robots that combine thin manipulators and endoscopes have the potential to address this by integrating seamlessly into the clinical workflow and enhancing dexterity. As a case study illustrating the potential of this approach, we describe a hand-held robotic system that passes two concentric tube manipulators through a 5 mm port in a rigid endoscope for transurethral laser prostate surgery. This system is intended to catalyze the use of a clinically superior, yet rarely attempted, procedure for benign prostatic hyperplasia. This paper describes system design and experiments to evaluate the surgeon's functional workspace and accuracy using the robot. Phantom and cadaver experiments demonstrate successful completion of the target procedure via prostate lobe resection.

Assessing the role of GPs in Nordic health care systems.

Science.gov (United States)

Quaye, Randolph K

2016-05-03

Purpose This paper examines the changing role of general practitioners (GPs) in Nordic countries of Sweden, Norway and Denmark. It aims to explore the "gate keeping" role of GPs in the face of current changes in the health care delivery systems in these countries. Design/methodology/approach Data were collected from existing literature, interviews with GPs, hospital specialists and representatives of Danish regions and Norwegian Medical Association. Findings The paper contends that in all these changes, the position of the GPs in the medical division of labor has been strengthened, and patients now have increased and broadened access to choice. Research limitations/implications Health care cost and high cancer mortality rates have forced Nordic countries of Sweden, Norway and Denmark to rethink their health care systems. Several attempts have been made to reduce health care cost through market reform and by strenghtening the position of GPs. The evidence suggests that in Norway and Denmark, right incentives are in place to achieve this goal. Sweden is not far behind. The paper has limitations of a small sample size and an exclusive focus on GPs. Practical implications Anecdotal evidence suggests that physicians are becoming extremely unhappy. Understanding the changing status of primary care physicians will yield valuable information for assessing the effectiveness of Nordic health care delivery systems. Social implications This study has wider implications of how GPs see their role as potential gatekeepers in the Nordic health care systems. The role of GPs is changing as a result of recent health care reforms. Originality/value This paper contends that in Norway and Denmark, right incentives are in place to strengthen the position of GPs.

Differences between Practice Patterns of Conventional and Naturopathic GPs in Germany.

Science.gov (United States)

Laux, Gunter; Musselmann, Berthold; Kiel, Marion; Szecsenyi, Joachim; Joos, Stefanie

2016-01-01

Limited evidence exists whether practice patterns of general practitioners (GPs) who have additionally completed training in naturopathy are different from those of conventional GPs. We aimed to assess and compare practice patterns of GPs in conventional and naturopathic GPs. Routine data from 41 GPs (31 with and 11 without additional qualification in NP, respectively) and 180,789 patients, drawn from the CONTinuous morbidity registration Epidemiologic NeTwork (CONTENT)-registry and collected between 2009 and 2014, were used. To assess practice patterns determinants of (non-)phytopharmaceutical prescriptions, referrals and hospitalizations were analyzed using mixed-effects Poisson regression models. As explanatory variables, the qualification of the GP in NM, the age group and sex of the patient, as well as bivariate interactions between these variables were considered. GPs additionally qualified in naturopathy exhibited higher rates of phytopharmaceutical prescriptions (pGPs. This association was not observed with respect to non-phytopharmaceutical prescriptions. However, interaction effects between qualification and age group as well as sex were present with respect to both phytopharmaceutical and non-phytopharmaceutical prescriptions (all pGPs could be subject to certain age groups and sex. However, the magnitude of these differences seem to be rather small.

Maintaining radiation exposures as low as reasonably achievable (ALARA) for dental personnel operating portable hand-held x-ray equipment.

Science.gov (United States)

McGiff, Thomas J; Danforth, Robert A; Herschaft, Edward E

2012-08-01

Clinical experience indicates that newly available portable hand-held x-ray units provide advantages compared to traditional fixed properly installed and operated x-ray units in dental radiography. However, concern that hand-held x-ray units produce higher operator doses than fixed x-ray units has caused regulatory agencies to mandate requirements for use of hand-held units that go beyond those recommended by the manufacturer and can discourage the use of this technology. To assess the need for additional requirements, a hand-held x-ray unit and a pair of manikins were used to measure the dose to a simulated operator under two conditions: exposures made according to the manufacturer's recommendations and exposures made according to manufacturer's recommendation except for the removal of the x-ray unit's protective backscatter shield. Dose to the simulated operator was determined using an array of personal dosimeters and a pair of pressurized ion chambers. The results indicate that the dose to an operator of this equipment will be less than 0.6 mSv y⁻¹ if the device is used according to the manufacturer's recommendations. This suggests that doses to properly trained operators of well-designed, hand-held dental x-ray units will be below 1.0 mSv y⁻¹ (2% of the annual occupational dose limit) even if additional no additional operational requirements are established by regulatory agencies. This level of annual dose is similar to those reported as typical dental personnel using fixed x-ray units and appears to satisfy the ALARA principal for this class of occupational exposures.

Application of Suresight handheld auto-refractometer in refraction screening for infants in Community Health Service Center

Directory of Open Access Journals (Sweden)

Li-Hua Guo

2014-08-01

Full Text Available AIM: To observe the application of Suresight handheld auto-refractometer in measuring diopter of infants in Community Health Service Center. METHODS:Totally 836 cases(1 672 eyesfrom June 2013 to December 2013 were examined diopter of infants by Suresight handheld auto-refractometer in Community Health Service Center. RESULTS: Within 1 672 eyes of 836 infants were examined, 202 eyes were diagnosed ametropia, 38 eyes were suspicious, 240 eyes were transferred to the department of ophthalmology, the referral rate was 14.35%; 172 eyes were diagnosed ametropia, and the diagnosis rate of the referral patients was 71.67%. Among 172 eyes, 46 eyes were provided with corrected glasses, accounting for 2.75% of the number of screening, and 126 eyes were given intensive monitoring, accounting for 7.54% of the number of screening.CONCLUSION: Application of Suresight handheld auto-refractometer in refraction screening for infants in Community Health Service Center is convenient and effective. With two-way referral between community health service center and department of ophthalmology can monitor and intervene vision development of infants much earlier.

The Statistics of GPS

National Research Council Canada - National Science Library

Matsakis, Demetrios

2007-01-01

The Global Positioning System (GPS) is an extremely effective satellite-based system that broadcasts sufficient information for a user to determine time and position from any location on or near the Earth...

A new mobile application for maintenance tasks in photovoltaic installations by using GPS data

International Nuclear Information System (INIS)

Fernández-Pacheco, D.G.; Molina-Martínez, J.M.; Ruiz-Canales, A.; Jiménez, M.

2012-01-01

Highlights: ► Portable and easy-to-use solution to detect possible failures at a PV installation. ► Calculation of solar and photovoltaic parameters by using a mobile device with GPS. ► No software which confers this utility to a mobile device can be found in the market. - Abstract: The application of the Information and Communication Technologies (ICTs) to the photovoltaic (PV) energy sector has increased notably in the last years. This paper presents a new mobile software application for maintenance tasks in PV installations by determining the PV output power of the system, the daily energy production, the clear-sky global solar radiation and other parameters associated with solar position from Global Position Data in handheld devices endowed with Android or Windows Mobile operating systems. The calculation of these parameters permits a technician to know if the PV plant is working properly, since the difference between the PV output power supplied by the installation in a clear-sky day for a determined hourly period and the values estimated by the application should be minimal. In case of fixed installations, the application also permits to determine if the PV module support structures of the installation are correctly oriented. Some comparisons between data supplied by four real PV installations and data calculated by the proposed application were performed for evaluation purposes.

GPS sledovací systém

OpenAIRE

Hofman, Jan

2010-01-01

V práci je popsán základní princip a vlastnosti globálního pozičního systému GPS. Je zde přiblížena problematika určování polohy, rychlosti a nadmořské výšky. Tyto poznatky jsou dále použity pro návrh zařízení, které komunikuje s běžně vyráběným GPS přijímačem a z něj získané informace zpracovává a ukládá do paměti pro pozdější vyhodnocení The keystone and properties of Global Position System (GPS) are described in this thesis. The thesis explains questions of position, speed and elevation...

Effects of Reentry Plasma Sheath on GPS Patch Antenna Polarization Property

Directory of Open Access Journals (Sweden)

L. Zhao

2013-01-01

Full Text Available A plasma sheath enveloping a reentry vehicle would affect performances of on-board antenna greatly, especially the navigation antennas. This paper studies the effects of reentry plasma sheath on a GPS right-hand circularly polarized (RHCP patch antenna polarization property during a typical reentry process. Utilizing the algorithm of finite integration technique, the polarization characteristic of a GPS antenna coated by a plasma sheath is obtained. Results show that the GPS RHCP patch antenna radiation pattern distortions as well as polarization deteriorations exist during the entire reentry process, and the worst polarization mismatch loss between a GPS antenna and RHCP GPS signal is nearly 3 dB. This paper also indicates that measures should be taken to alleviate the plasma sheath for maintaining the GPS communication during the reentry process.

Classification and Visualization of Physical and Chemical Properties of Falsified Medicines with Handheld Raman Spectroscopy and X-Ray Computed Tomography.

Science.gov (United States)

Kakio, Tomoko; Yoshida, Naoko; Macha, Susan; Moriguchi, Kazunobu; Hiroshima, Takashi; Ikeda, Yukihiro; Tsuboi, Hirohito; Kimura, Kazuko

2017-09-01

Analytical methods for the detection of substandard and falsified medical products (SFs) are important for public health and patient safety. Research to understand how the physical and chemical properties of SFs can be most effectively applied to distinguish the SFs from authentic products has not yet been investigated enough. Here, we investigated the usefulness of two analytical methods, handheld Raman spectroscopy (handheld Raman) and X-ray computed tomography (X-ray CT), for detecting SFs among oral solid antihypertensive pharmaceutical products containing candesartan cilexetil as an active pharmaceutical ingredient (API). X-ray CT visualized at least two different types of falsified tablets, one containing many cracks and voids and the other containing aggregates with high electron density, such as from the presence of the heavy elements. Generic products that purported to contain equivalent amounts of API to the authentic products were discriminated from the authentic products by the handheld Raman and the different physical structure on X-ray CT. Approach to investigate both the chemical and physical properties with handheld Raman and X-ray CT, respectively, promise the accurate discrimination of the SFs, even if their visual appearance is similar with authentic products. We present a decision tree for investigating the authenticity of samples purporting to be authentic commercial tablets. Our results indicate that the combination approach of visual observation, handheld Raman and X-ray CT is a powerful strategy for nondestructive discrimination of suspect samples.

GPS Estimates of Integrated Precipitable Water Aid Weather Forecasters

Science.gov (United States)

Moore, Angelyn W.; Gutman, Seth I.; Holub, Kirk; Bock, Yehuda; Danielson, David; Laber, Jayme; Small, Ivory

2013-01-01

Global Positioning System (GPS) meteorology provides enhanced density, low-latency (30-min resolution), integrated precipitable water (IPW) estimates to NOAA NWS (National Oceanic and Atmospheric Adminis tration Nat ional Weather Service) Weather Forecast Offices (WFOs) to provide improved model and satellite data verification capability and more accurate forecasts of extreme weather such as flooding. An early activity of this project was to increase the number of stations contributing to the NOAA Earth System Research Laboratory (ESRL) GPS meteorology observing network in Southern California by about 27 stations. Following this, the Los Angeles/Oxnard and San Diego WFOs began using the enhanced GPS-based IPW measurements provided by ESRL in the 2012 and 2013 monsoon seasons. Forecasters found GPS IPW to be an effective tool in evaluating model performance, and in monitoring monsoon development between weather model runs for improved flood forecasting. GPS stations are multi-purpose, and routine processing for position solutions also yields estimates of tropospheric zenith delays, which can be converted into mm-accuracy PWV (precipitable water vapor) using in situ pressure and temperature measurements, the basis for GPS meteorology. NOAA ESRL has implemented this concept with a nationwide distribution of more than 300 "GPSMet" stations providing IPW estimates at sub-hourly resolution currently used in operational weather models in the U.S.

Soil Moisture Retrieval Based on GPS Signal Strength Attenuation

Directory of Open Access Journals (Sweden)

Franziska Koch

2016-07-01

Full Text Available Soil moisture (SM is a highly relevant variable for agriculture, the emergence of floods and a key variable in the global energy and water cycle. In the last years, several satellite missions have been launched especially to derive large-scale products of the SM dynamics on the Earth. However, in situ validation data are often scarce. We developed a new method to retrieve SM of bare soil from measurements of low-cost GPS (Global Positioning System sensors that receive the freely available GPS L1-band signals. The experimental setup of three GPS sensors was installed at a bare soil field at the German Weather Service (DWD in Munich for almost 1.5 years. Two GPS antennas were installed within the soil column at a depth of 10 cm and one above the soil. SM was successfully retrieved based on GPS signal strength losses through the integral soil volume. The results show high agreement with measured and modelled SM validation data. Due to its non-destructive, cheap and low power setup, GPS sensor networks could also be used for potential applications in remote areas, aiming to serve as satellite validation data and to support the fields of agriculture, water supply, flood forecasting and climate change.

Adaptive RF front-ends for hand-held applications

CERN Document Server

van Bezooijen, Andre; van Roermund, Arthur

2010-01-01

The RF front-end - antenna combination is a vital part of a mobile phone because its performance is very relevant to the link quality between hand-set and cellular network base-stations. The RF front-end performance suffers from changes in operating environment, like hand-effects, that are often unpredictable. ""Adaptive RF Front-Ends for Hand-Held Applications"" presents an analysis on the impact of fluctuating environmental parameters. In order to overcome undesired behavior two different adaptive control methods are treated that make RF frond-ends more resilient: adaptive impedance control,

Ionospheric correction for spaceborne single-frequency GPS based ...

Indian Academy of Sciences (India)

A modified ionospheric correction method and the corresponding approximate algorithm for spaceborne single-frequency Global Positioning System (GPS) users are proposed in this study. Single Layer Model (SLM) mapping function for spaceborne GPS was analyzed. SLM mapping functions at different altitudes were ...

Handheld Longwave Infrared Camera Based on Highly-Sensitive Quantum Well Infrared Photodetectors, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — We propose to develop a compact handheld longwave infrared camera based on quantum well infrared photodetector (QWIP) focal plane array (FPA) technology. Based on...

A data-driven design evaluation tool for handheld device soft keyboards.

Directory of Open Access Journals (Sweden)

Matthieu B Trudeau

Full Text Available Thumb interaction is a primary technique used to operate small handheld devices such as smartphones. Despite the different techniques involved in operating a handheld device compared to a personal computer, the keyboard layouts for both devices are similar. A handheld device keyboard that considers the physical capabilities of the thumb may improve user experience. We developed and applied a design evaluation tool for different geometries of the QWERTY keyboard using a performance evaluation model. The model utilizes previously collected data on thumb motor performance and posture for different tap locations and thumb movement directions. We calculated a performance index (PITOT, 0 is worst and 2 is best for 663 designs consisting in different combinations of three variables: the keyboard's radius of curvature (R (mm, orientation (O (°, and vertical location on the screen (L. The current standard keyboard performed poorly (PITOT = 0.28 compared to other designs considered. Keyboard location (L contributed to the greatest variability in performance out of the three design variables, suggesting that designers should modify this variable first. Performance was greatest for designs in the middle keyboard location. In addition, having a slightly upward curve (R = -20 mm and orientated perpendicular to the thumb's long axis (O = -20° improved performance to PITOT = 1.97. Poorest performances were associated with placement of the keyboard's spacebar in the bottom right corner of the screen (e.g., the worst was for R = 20 mm, O = 40°, L =  Bottom (PITOT = 0.09. While this evaluation tool can be used in the design process as an ergonomic reference to promote user motor performance, other design variables such as visual access and usability still remain unexplored.

Integrated INS/GPS Navigation from a Popular Perspective

Science.gov (United States)

Omerbashich, Mensur

2002-01-01

Inertial navigation, blended with other navigation aids, Global Positioning System (GPS) in particular, has gained significance due to enhanced navigation and inertial reference performance and dissimilarity for fault tolerance and anti-jamming. Relatively new concepts based upon using Differential GPS (DGPS) blended with Inertial (and visual) Navigation Sensors (INS) offer the possibility of low cost, autonomous aircraft landing. The FAA has decided to implement the system in a sophisticated form as a new standard navigation tool during this decade. There have been a number of new inertial sensor concepts in the recent past that emphasize increased accuracy of INS/GPS versus INS and reliability of navigation, as well as lower size and weight, and higher power, fault tolerance, and long life. The principles of GPS are not discussed; rather the attention is directed towards general concepts and comparative advantages. A short introduction to the problems faced in kinematics is presented. The intention is to relate the basic principles of kinematics to probably the most used navigation method in the future-INS/GPS. An example of the airborne INS is presented, with emphasis on how it works. The discussion of the error types and sources in navigation, and of the role of filters in optimal estimation of the errors then follows. The main question this paper is trying to answer is 'What are the benefits of the integration of INS and GPS and how is this, navigation concept of the future achieved in reality?' The main goal is to communicate the idea about what stands behind a modern navigation method.

Comparative Geometrical Accuracy Investigations of Hand-Held 3d Scanning Systems - AN Update

Science.gov (United States)

Kersten, T. P.; Lindstaedt, M.; Starosta, D.

2018-05-01

Hand-held 3D scanning systems are increasingly available on the market from several system manufacturers. These systems are deployed for 3D recording of objects with different size in diverse applications, such as industrial reverse engineering, and documentation of museum exhibits etc. Typical measurement distances range from 0.5 m to 4.5 m. Although they are often easy-to-use, the geometric performance of these systems, especially the precision and accuracy, are not well known to many users. First geometrical investigations of a variety of diverse hand-held 3D scanning systems were already carried out by the Photogrammetry & Laser Scanning Lab of the HafenCity University Hamburg (HCU Hamburg) in cooperation with two other universities in 2016. To obtain more information about the accuracy behaviour of the latest generation of hand-held 3D scanning systems, HCU Hamburg conducted further comparative geometrical investigations using structured light systems with speckle pattern (Artec Spider, Mantis Vision PocketScan 3D, Mantis Vision F5-SR, Mantis Vision F5-B, and Mantis Vision F6), and photogrammetric systems (Creaform HandySCAN 700 and Shining FreeScan X7). In the framework of these comparative investigations geometrically stable reference bodies were used. The appropriate reference data was acquired by measurements with two structured light projection systems (AICON smartSCAN and GOM ATOS I 2M). The comprehensive test results of the different test scenarios are presented and critically discussed in this contribution.

Profile of English salaried GPs: labour mobility and practice performance.

Science.gov (United States)

Ding, Alexander; Hann, Mark; Sibbald, Bonnie

2008-01-01

Recent national policy changes have provided greater flexibility in GPs' contracts. One such policy is salaried employment, which offers reduced hours and freedom from out-of-hours and administrative responsibilities, aimed at improving recruitment and retention in a labour market facing regional shortages. To profile salaried GPs and assess their mobility within the labour market. Serial cross-sectional study. All GPs practising in England during the years 1996/1997, 2000/2001, and 2004/2005. Descriptive analyses, logistic regression. Salaried GPs tended to be either younger ( or =65 years), female, or overseas-qualified; they favoured part-time working and personal medical services contracts. Salaried GPs were more mobile than GP principals, and have become increasingly so, despite a trend towards reduced overall mobility in the GP workforce. Practices with salaried GPs scored more Quality and Outcomes Framework points and were located in slightly more affluent areas. Salaried status appears to have reduced limitations in the labour market, leading to better workforce deployment from a GP's perspective. However, there is no evidence to suggest it has relieved inequalities in GP distribution.

Modeling of the Near Field Coupling Between an External Loop and an Implantable Spiral Chip Antennas in Biosensor Systems

Science.gov (United States)

Simons, Rainee N.; Miranda, Felix A.

2006-01-01

In this paper, the near field coupling between an external hand-held loop antenna and an implantable miniature (1x1 mm) printed square spiral chip antenna used in bio-MEMS sensors for contact-less powering and RF telemetry is investigated. The loop and the spiral are inductively coupled and effectively form a transformer. The numerical results include the quasi-stationary magnetic field pattern of the implanted antenna, near zone wave impedance as a function of the radial distance and the values of the lumped elements in the equivalent circuit model for the transformer.

A Fresh Look at the Crystal Violet Lab with Handheld Camera Colorimetry

Science.gov (United States)

Knutson, Theodore R.; Knutson, Cassandra M.; Mozzetti, Abbie R.; Campos, Antonio R.; Haynes, Christy L.; Penn, R. Lee

2015-01-01

Chemical kinetic experiments to determine rate laws are common in high school and college chemistry courses. For reactions involving a color change, rate laws can be determined experimentally using spectrophotometric or colorimetric equipment though this equipment can be cost prohibitive. Previous work demonstrated that inexpensive handheld camera…

Accuracy of velocities from repeated GPS surveys: relative positioning is concerned

Science.gov (United States)

Duman, Huseyin; Ugur Sanli, D.

2016-04-01

Over more than a decade, researchers have been interested in studying the accuracy of GPS positioning solutions. Recently, reporting the accuracy of GPS velocities has been added to this. Researchers studying landslide motion, tectonic motion, uplift, sea level rise, and subsidence still report results from GPS experiments in which repeated GPS measurements from short sessions are used. This motivated some other researchers to study the accuracy of GPS deformation rates/velocities from various repeated GPS surveys. In one of the efforts, the velocity accuracy was derived from repeated GPS static surveys using short observation sessions and Precise Point Positioning mode of GPS software. Velocities from short GPS sessions were compared with the velocities from 24 h sessions. The accuracy of velocities was obtained using statistical hypothesis testing and quantifying the accuracy of least squares estimation models. The results reveal that 45-60 % of the horizontal and none of the vertical solutions comply with the results from 24 h solutions. We argue that this case in which the data was evaluated using PPP should also apply to the case in which the data belonging to long GPS base lengths is processed using fundamental relative point positioning. To test this idea we chose the two IGS stations ANKR and NICO and derive their velocities from the reference stations held fixed in the stable EURASIAN plate. The University of Bern's GNSS software BERNESE was used to produce relative positioning solutions, and the results are compared with those of GIPSY/OASIS II PPP results. First impressions indicate that it is worth designing a global experiment and test these ideas in detail.

Torque Removal Evaluation of Screw in One-Piece and Two-Piece Abutments Tightened with a Handheld screwdriver

Directory of Open Access Journals (Sweden)

Jalil Ghanbarzadeh

2013-12-01

Full Text Available Introduction: Some clinicians use a handheld screw driver instead of a torque wrench to definitively tighten abutment screws. The aim of this study was to compare the removal torque of one-piece and two-piece abutments tightened with a handheld driver and a torque control ratchet. Methods: 40 ITI implants were placed in acrylic blocks and divided into 4 groups. In groups one and two, 10 ITI one-piece abutments (Solid® and in groups three and four, 10 ITI two-piece abutments (Synocta® were placed on the implants. In groups one and three abutments were tightened by 5 experienced males and 5 experienced females using a handheld driver. In groups two and four abutments were tightened using a torque wrench with torque values of 10, 20 and 35 N.cm. Insertion torque and removal torque values of the abutments were measured with a digital torque meter. Results: The insertion torque values (ITVs of males in both abutments were significantly higher than those of females. ITVs in both Solid® and Synocta® abutments tightened with a handheld screwdriver were similar to the torque of 20 N.cm in the torque wrench. Removal torque values (RTVs of solid® abutments were higher than those of synocta® abutments. Conclusion: The one- piece abutments (solid® showed higher RTVs than the two-piece abutments (synocta®. Hand driver does not produce sufficient preload force for the final tightening of the abutment

GPS system simulation methodology

Science.gov (United States)

Ewing, Thomas F.

1993-01-01

The following topics are presented: background; Global Positioning System (GPS) methodology overview; the graphical user interface (GUI); current models; application to space nuclear power/propulsion; and interfacing requirements. The discussion is presented in vugraph form.

Briefing Highlights Vulnerability of GPS to Adverse Space Weather

Science.gov (United States)

Balcerak, Ernie

2011-08-01

Through its effects on GPS and other technologies, space weather can affect a variety of industries, including agriculture, commercial air travel, and emergency response. Speakers focused on these topics at a 22 June briefing on Capitol Hill in Washington, D. C. Solar flares can produce radio bursts that directly interfere with GPS signals. Solar activity can also cause ionospheric disturbances that produce distortions and delays in GPS signals, degrading the accuracy of positioning and navigation systems.

GeoTravel: Harvesting Ambient Geographic Footprints from GPS Trajectories

OpenAIRE

Liew, Li Ching; Goh, Ong Sing

2014-01-01

This study is about harvesting point of interest from GPS trajectories. Trajectories are the paths that moving objects move by follow through space in a function of time while GPS trajectories generally are point-sequences with geographic coordinates, time stamp, speed and heading. User can get information from GPS enable device. For example, user can acquire present location, search the information around them and design driving routes to a destination and thus design travel itineraries. By ...

Greenland ice mass balance from GPS, GRACE and ICESat

DEFF Research Database (Denmark)

Khan, Shfaqat Abbas; Kjær, Kurt H.; Korsgaard, Niels Jákup

Greenland, using stereoscopic coverage by aerial photographs recorded in 1985, and subsequent comparative surface elevation data from ICESat (Ice, Cloud and land Elevation Satellite) and ATM (Airborne Topographic Mapper) supplemented with measurements from GPS and the Gravity Recovery and Climate Experiment...... (GRACE) satellite gravity mission, launched in March, 2002. The GRACE results provide a direct measure of mass loss, while the GPS data are used to monitor crustal uplift caused by ice mass loss close to the GPS sites....

GPS/MEMS IMU/Microprocessor Board for Navigation

Science.gov (United States)

Gender, Thomas K.; Chow, James; Ott, William E.

2009-01-01

A miniaturized instrumentation package comprising a (1) Global Positioning System (GPS) receiver, (2) an inertial measurement unit (IMU) consisting largely of surface-micromachined sensors of the microelectromechanical systems (MEMS) type, and (3) a microprocessor, all residing on a single circuit board, is part of the navigation system of a compact robotic spacecraft intended to be released from a larger spacecraft [e.g., the International Space Station (ISS)] for exterior visual inspection of the larger spacecraft. Variants of the package may also be useful in terrestrial collision-detection and -avoidance applications. The navigation solution obtained by integrating the IMU outputs is fed back to a correlator in the GPS receiver to aid in tracking GPS signals. The raw GPS and IMU data are blended in a Kalman filter to obtain an optimal navigation solution, which can be supplemented by range and velocity data obtained by use of (l) a stereoscopic pair of electronic cameras aboard the robotic spacecraft and/or (2) a laser dynamic range imager aboard the ISS. The novelty of the package lies mostly in those aspects of the design of the MEMS IMU that pertain to controlling mechanical resonances and stabilizing scale factors and biases.

Crustal deformations at permanent GPS sites in Denmark

DEFF Research Database (Denmark)

Khan, Shfaqat Abbas; Knudsen, Per; Tscherning, Carl Christian

2005-01-01

The National Survey and Cadastre (KMS) is responsible for the geodetic definition of the reference network in Denmark. Permanent GPS stations play an important role in the monitoring and maintenance of the geodetic network. During 1998 and 1999 KMS established three permanent GPS station in Denma...

GPS Technology and Human Psychological Research: A Methodological Proposal

Directory of Open Access Journals (Sweden)

Pedro S. A. Wolf

2010-10-01

Full Text Available Animal behaviorists have made extensive use of GPS technology since 1991. In contrast, psychological research has made little use of the technology, even though the technology is relatively inexpensive, familiar, and widespread. Hence, its potential for pure and applied psychological research remains untapped. We describe three methods psychologists could apply to individual differences research, clinical research, or spatial use research. In the context of individual differences research, GPS technology permits us to test hypotheses predicting specific relations among patterns of spatial use and individual differences variables. In a clinical context, GPS technology provides outcome measures that may relate to the outcome of interventions designed to treat psychological disorders that, for example, may leave a person homebound (e.g. Agoraphobia, PTSD, TBI. Finally, GPS technology provides natural measures of spatial use. We, for example, used GPS technology to quantify traffic flow and exhibit use at the Arizona Sonora Desert Museum. Interested parties could easily extend this methodology some aspects of urban planning or business usage.DOI: 10.2458/azu_jmmss.v1i1.74

IceBridge GPS L0 Raw Satellite Navigation Data

Data.gov (United States)

National Aeronautics and Space Administration — The NASA IceBridge GPS L0 Raw Satellite Navigation Data (IPUTG0) data set contains GPS readings, including latitude, longitude, track, ground speed, off distance,...

Physical applications of GPS geodesy: a review.

Science.gov (United States)

Bock, Yehuda; Melgar, Diego

2016-10-01

Geodesy, the oldest science, has become an important discipline in the geosciences, in large part by enhancing Global Positioning System (GPS) capabilities over the last 35 years well beyond the satellite constellation's original design. The ability of GPS geodesy to estimate 3D positions with millimeter-level precision with respect to a global terrestrial reference frame has contributed to significant advances in geophysics, seismology, atmospheric science, hydrology, and natural hazard science. Monitoring the changes in the positions or trajectories of GPS instruments on the Earth's land and water surfaces, in the atmosphere, or in space, is important for both theory and applications, from an improved understanding of tectonic and magmatic processes to developing systems for mitigating the impact of natural hazards on society and the environment. Besides accurate positioning, all disturbances in the propagation of the transmitted GPS radio signals from satellite to receiver are mined for information, from troposphere and ionosphere delays for weather, climate, and natural hazard applications, to disturbances in the signals due to multipath reflections from the solid ground, water, and ice for environmental applications. We review the relevant concepts of geodetic theory, data analysis, and physical modeling for a myriad of processes at multiple spatial and temporal scales, and discuss the extensive global infrastructure that has been built to support GPS geodesy consisting of thousands of continuously operating stations. We also discuss the integration of heterogeneous and complementary data sets from geodesy, seismology, and geology, focusing on crustal deformation applications and early warning systems for natural hazards.

A System to Produce Precise Global GPS Network Solutions for all Geodetic GPS Stations in the World

Science.gov (United States)

Blewitt, G.; Kreemer, C. W.

2010-12-01

We have developed an end-to-end system that automatically seeks and routinely retrieves geodetic GPS data from ~5000 stations (currently) around the globe, reduces the data into unique, daily global network solutions, and produces high precision time series for station coordinates ready for time-series analysis, geophysical modeling and interpretation. Moreover, “carrier range” data are produced for all stations, enabling epoch-by-epoch tracking of individual station motions by precise point positioning for investigation of sub-daily processes, such as post-seismic after-slip and ocean tidal loading. Solutions are computed in a global reference frame aligned to ITRF, and optionally in user-specified continental-scale reference frames that can filter out common-mode signals to enhance regional strain anomalies. We describe the elements of this system, the underlying signal processing theory, the products, operational statistics, and scientific applications of our system. The system is fundamentally based on precise point positioning using JPL's GIPSY OASIS II software, coupled with ambiguity resolution and a global network adjustment of ~300,000 parameters per day using our newly developed Ambizap3 software. The system is designed to easily and efficiently absorb stations that deliver data very late, by recycling prior computations in the network adjustment, such that the resulting network solution is identical to starting from scratch. Thus, it becomes possible to trawl continuously the Internet for late arriving data, or for newly discovered data, and seamlessly update all GPS station time series using the new information content. As new stations are added to the processing archive, automated e-mail requests are made to H.-G. Scherneck's server at Chalmers University to compute ocean loading coefficients used by the station motion model. Rinex file headers are parsed and compared with alias tables in order to infer the correct receiver type and antenna

Kinematic GPS survey as validation of LIDAR strips accuracy

Directory of Open Access Journals (Sweden)

C. Gordini

2006-06-01

Full Text Available As a result of the catastrophic hydrogeological events which occurred in May 1998 in Campania, in the south of Italy, the distinctive features of airborne laser scanning mounted on a helicopter were used to survey the landslides at Sarno and Quindici. In order to survey the entire zone of interest, approximately 21 km2, it was necessary to scan 12 laser strips. Many problems arose during the survey: difficulties in receiving the GPS signal, complex terrain features and unfavorable atmospheric conditions. These problems were investigated and it emerged that one of the most influential factors is the quality of GPS signals. By analysing the original GPS data, the traces obtained by fixing phase ambiguity with an On The Fly (OTF algorithm were isolated from those with smoothed differential GPS solution (DGPS. Processing and analysis of laser data showed that not all the overlapping laser strips were congruent with each other. Since an external survey to verify the laser data accuracy was necessary, it was decided to utilize the kinematic GPS technique. The laser strips were subsequently adjusted, using the kinematic GPS data as reference points. Bearing in mind that in mountainous areas like the one studied here it is not possible to obtain nominal precision and accuracy, a good result was nevertheless obtained with a Digital Terrain Model (DTM of all the zones of interest.

Seasonal and circadian biases in bird tracking with solar GPS-tags

OpenAIRE

Silva, Rafa; Afán, Isabel; Gil, Juan A.; Bustamante, Javier

2017-01-01

Global Positioning System (GPS) tags are nowadays widely used in wildlife tracking. This geolocation technique can suffer from fix loss biases due to poor satellite GPS geometry, that result in tracking data gaps leading to wrong research conclusions. In addition, new solar-powered GPS tags deployed on birds can suffer from a new "battery drain bias" currently ignored in movement ecology analyses. We use a GPS tracking dataset of bearded vultures (Gypaetus barbatus), tracked for several years...

The application of GPS time information in the telemetry ground station

International Nuclear Information System (INIS)

Zhang Songtao; Zhang Yusong; Sun Xiurui

2001-01-01

GPS time information is a kind of practicable information resource that can be shared all over the world. Now it is the most accurate wireless time information. The major of this paper is the application information of GPS time information in telemetry. The main point introduces how to make use of the GPS time information to produce GPS-IRIG-B time code for proving ground and how to send time information to related equipment in telemetry ground station

High-precision coseismic displacement estimation with a single-frequency GPS receiver

Science.gov (United States)

Guo, Bofeng; Zhang, Xiaohong; Ren, Xiaodong; Li, Xingxing

2015-07-01

To improve the performance of Global Positioning System (GPS) in the earthquake/tsunami early warning and rapid response applications, minimizing the blind zone and increasing the stability and accuracy of both the rapid source and rupture inversion, the density of existing GPS networks must be increased in the areas at risk. For economic reasons, low-cost single-frequency receivers would be preferable to make the sparse dual-frequency GPS networks denser. When using single-frequency GPS receivers, the main problem that must be solved is the ionospheric delay, which is a critical factor when determining accurate coseismic displacements. In this study, we introduce a modified Satellite-specific Epoch-differenced Ionospheric Delay (MSEID) model to compensate for the effect of ionospheric error on single-frequency GPS receivers. In the MSEID model, the time-differenced ionospheric delays observed from a regional dual-frequency GPS network to a common satellite are fitted to a plane rather than part of a sphere, and the parameters of this plane are determined by using the coordinates of the stations. When the parameters are known, time-differenced ionospheric delays for a single-frequency GPS receiver could be derived from the observations of those dual-frequency receivers. Using these ionospheric delay corrections, coseismic displacements of a single-frequency GPS receiver can be accurately calculated based on time-differenced carrier-phase measurements in real time. The performance of the proposed approach is validated using 5 Hz GPS data collected during the 2012 Nicoya Peninsula Earthquake (Mw 7.6, 2012 September 5) in Costa Rica. This shows that the proposed approach improves the accuracy of the displacement of a single-frequency GPS station, and coseismic displacements with an accuracy of a few centimetres are achieved over a 10-min interval.

Handheld Delivery System for Modified Boron-Type Fire Extinguishment Agent

Science.gov (United States)

1993-11-01

was to develop and test a handheld portable delivery system for use with the modified boron-type fire extinguishing agent for metal fires . B...BACKGROUND A need exists for an extinguishing agent and accompanying delivery system that are effective against complex geometry metal fires . A modified...agent and its delivery system have proven effective against complex geometry metal fires containing up to 200 pounds of magnesium metal. Further

Handheld microwave bomb-detecting imaging system

Science.gov (United States)

Gorwara, Ashok; Molchanov, Pavlo

2017-05-01

Proposed novel imaging technique will provide all weather high-resolution imaging and recognition capability for RF/Microwave signals with good penetration through highly scattered media: fog, snow, dust, smoke, even foliage, camouflage, walls and ground. Image resolution in proposed imaging system is not limited by diffraction and will be determined by processor and sampling frequency. Proposed imaging system can simultaneously cover wide field of view, detect multiple targets and can be multi-frequency, multi-function. Directional antennas in imaging system can be close positioned and installed in cell phone size handheld device, on small aircraft or distributed around protected border or object. Non-scanning monopulse system allows dramatically decrease in transmitting power and at the same time provides increased imaging range by integrating 2-3 orders more signals than regular scanning imaging systems.

Modular Software for Spacecraft Navigation Using the Global Positioning System (GPS)

Science.gov (United States)

Truong, S. H.; Hartman, K. R.; Weidow, D. A.; Berry, D. L.; Oza, D. H.; Long, A. C.; Joyce, E.; Steger, W. L.

1996-01-01

The Goddard Space Flight Center Flight Dynamics and Mission Operations Divisions have jointly investigated the feasibility of engineering modular Global Positioning SYSTEM (GPS) navigation software to support both real time flight and ground postprocessing configurations. The goals of this effort are to define standard GPS data interfaces and to engineer standard, reusable navigation software components that can be used to build a broad range of GPS navigation support applications. The paper discusses the GPS modular software (GMOD) system and operations concepts, major requirements, candidate software architecture, feasibility assessment and recommended software interface standards. In additon, ongoing efforts to broaden the scope of the initial study and to develop modular software to support autonomous navigation using GPS are addressed,

Observational study of ionospheric irregularities and GPS scintillations associated with the 2012 tropical cyclone Tembin passing Hong Kong

Science.gov (United States)

Yang, Zhe; Liu, Zhizhao

2016-05-01

This study presents the ionospheric responses observed in Hong Kong to a Typhoon, namely, Tembin, from the aspects of the occurrence of ionospheric irregularities and scintillations, using Global Positioning System (GPS) observations from a ground-based GPS scintillation monitoring station in Hong Kong and from GPS receivers on board the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites. The ionospheric irregularities and scintillations are characterized by the rate of total electron content variation index (ROTI) and the amplitude scintillation index S4, respectively. The typhoon Tembin formed over the western North Pacific during 18-30 August 2012 and approached Hong Kong during 24-27 August 2012 with the closest distance 290 km from Hong Kong at around 17 universal time (UT) on 25 August 2012. The ground-based observations indicate that in the nighttime period of 20:00-02:00 local time (LT = UT + 8 h) on 26 August when Tembin passed closely to Hong Kong, the ionospheric irregularities and scintillations of GPS signals were observed in the south of Hong Kong, over the area of 13°N ~ 23°N in latitude and 110°E ~ 120°E in longitude. From the COSMIC observations, it shows that the number of radio occultation scintillation events peaks on 26 August 2012 during the passage of Tembin. Without the presence of strong geomagnetic or solar activity, it is suspected that gravity waves might be generated in the lower atmosphere and likely seed the formation of ionospheric plasma irregularities. This work for the first time from Hong Kong observes the sign of coupling between the lower atmosphere and ionosphere in a tropical cyclone event, combining both ground- and space-based GPS observation data.

CRCP-Acropora spp. distribution in the upper Florida Keys 2013-2015 (NCEI Accession 0157538)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains data from visual surveys by snorkelers using handheld GPS units to map extant live colonies of the threatened corals Acropora palmata and A....

CRCP-Acropora spp. distribution in the upper Florida Keys 2013-2015

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set is derived from visual surveys by snorkelers using handheld GPS units to map extant live colonies of the threatened corals Acropora palmata and A....

GPs' perceptions of workload in England: a qualitative interview study.

Science.gov (United States)

Croxson, Caroline Hd; Ashdown, Helen F; Hobbs, Fd Richard

2017-02-01

GPs report the lowest levels of morale among doctors, job satisfaction is low, and the GP workforce is diminishing. Workload is frequently cited as negatively impacting on commitment to a career in general practice, and many GPs report that their workload is unmanageable. To gather an in-depth understanding of GPs' perceptions and attitudes towards workload. All GPs working within NHS England were eligible. Advertisements were circulated via regional GP e-mail lists and national social media networks in June 2015. Of those GPs who responded, a maximum-variation sample was selected until data saturation was reached. Semi-structured, qualitative interviews were conducted. Data were analysed thematically. In total, 171 GPs responded, and 34 were included in this study. GPs described an increase in workload over recent years, with current working days being long and intense, raising concerns over the wellbeing of GPs and patients. Full-time partnership was generally not considered to be possible, and many participants felt workload was unsustainable, particularly given the diminishing workforce. Four major themes emerged to explain increased workload: increased patient needs and expectations; a changing relationship between primary and secondary care; bureaucracy and resources; and the balance of workload within a practice. Continuity of care was perceived as being eroded by changes in contracts and working patterns to deal with workload. This study highlights the urgent need to address perceived lack of investment and clinical capacity in general practice, and suggests that managing patient expectations around what primary care can deliver, and reducing bureaucracy, have become key issues, at least until capacity issues are resolved. © British Journal of General Practice 2017.

USGS Earthquake Program GPS Use Case : Earthquake Early Warning

Science.gov (United States)

2015-03-12

USGS GPS receiver use case. Item 1 - High Precision User (federal agency with Stafford Act hazard alert responsibilities for earthquakes, volcanoes and landslides nationwide). Item 2 - Description of Associated GPS Application(s): The USGS Eart...

Radiotracking large wilderness mammals: Integration of GPS and Argos technology

Science.gov (United States)

Schwartz, Charles C.; Arthur, Steve M.

1999-01-01

We tested 30 prototype global positioning system (GPS) radiocollars on brown bears (Ursus arctos) over a 3-year period on the Kenai Peninsula, Alaska. Collars were of 2 design types: GPS with an Argos (Argos Data collection and Location System) satellite uplink (n=19) and GPS unites where the data were stored on board (n=10) for retrieval at a later date. All units also contained a conventional VHF (very high frequency) transmitter and weighed 1.7 kg. GPS-Argos united obtained 10-82% of expected GPS fixes, and fix rate declined significantly (Pbears varied more and were lower than fix rates for stationary collars placed in various vegetation types, suggesting that the bear, terrain, and movement all influence both fix and uplink success rate. Application of this new technology to grizzly and brown bear research and comparisons to studies with moose (Alces alces) are discussed.

Handheld Versus Wearable Interaction Design for Professionals - A Case Study of Hospital Service Work

DEFF Research Database (Denmark)

Stisen, Allan; Blunck, Henrik; Kjærgaard, Mikkel Baun

2014-01-01

With the blooming of new available wrist worn devices there are potentials for these to support the work done in many professional domains. One such domain is hospital service work. This paper explores two wearable prototypes with regards to challenges and opportunities to support future hospital...... service work. This explorative study was conducted with 4 experienced hospital orderlies who interacted with an application across two wearable concepts, and one handheld smartphone in five scenarios in a hospital environment. The interaction was video recorded with a chest-mounted video afterwards semi...... structured interviews with each participant was conducted. This study shows that wearable computers can effectively support the maintenance work of the orderlies and has domain specific advantages over the handheld smartphone, e.g., the former support glancing at the task information. Furthermore, we outline...

Data Integration from GPS and Inertial Navigation Systems for Pedestrians in Urban Area

Directory of Open Access Journals (Sweden)

Krzysztof Bikonis

2013-09-01

Full Text Available The GPS system is widely used in navigation and the GPS receiver can offer long-term stable absolute positioning information. The overall system performance depends largely on the signal environments. The position obtained from GPS is often degraded due to obstruction and multipath effect caused by buildings, city infrastructure and vegetation, whereas, the current performance achieved by inertial navigation systems (INS is still relatively poor due to the large inertial sensor errors. The complementary features of GPS and INS are the main reasons why integrated GPS/INS systems are becoming increasingly popular. GPS/INS systems offer a high data rate, high accuracy position and orientation that can work in all environments, particularly those where satellite availability is restricted. In the paper integration algorithm of GPS and INS systems data for pedestrians in urban area is presented. For data integration an Extended Kalman Filter (EKF algorithm is proposed. Complementary characteristics of GPS and INS with EKF can overcome the problem of huge INS drifts, GPS outages, dense multipath effect and other individual problems associated with these sensors.

Routing Unmanned Vehicles in GPS-Denied Environments

OpenAIRE

Sundar, Kaarthik; Misra, Sohum; Rathinam, Sivakumar; Sharma, Rajnikant

2017-01-01

Most of the routing algorithms for unmanned vehicles, that arise in data gathering and monitoring applications in the literature, rely on the Global Positioning System (GPS) information for localization. However, disruption of GPS signals either intentionally or unintentionally could potentially render these algorithms not applicable. In this article, we present a novel method to address this difficulty by combining methods from cooperative localization and routing. In particular, the article...

A Bridge Deflection Monitoring with GPS

Science.gov (United States)

Figurski, M.; Gałuszkiewicz, M.; Wrona, M.

2007-01-01

This paper introduces results of investigation carried on by The Applied Geomatics Section in Military University of Technology. Research includes possibilities of monitoring dynamic behavior of a bridge using high rate GPS data. Whole event was executed with collaboration of The Road and Bridge Management and The Warsaw Geodesy Company. Interdisciplinary approach with this project allows authors to get reliable information about investigating constructions and their respond for true traffic loading detected by GPS receivers. Way of compute data and used software (TRACK) are also shown in this paper.

[Evaluation of accuracy of measuring intraocular pressure by handheld non-contact applanation tonometer].

Science.gov (United States)

Chen, X; Peng, D; Zhou, W; Zhong, Y

1995-06-01

To evaluate the accuracy of measuring intraocular pressure by handheld non-contact applanation tonometer. 58 patients' (113 eyes) intraocular pressure were measured by Keeler, non-contact tonometer and R 900 Goldmann applanation tonometer and the results of measurement of intraocular pressure by the two kinds of tonometers were compared. The mean intraocular pressure measured by non-contact is 16.31 +/- 5.59 mmHg and 17.49 +/- 6.13 mmHg (1 mmHg = 0.1333 kPa) by Goldmann applanation tonometer, respectively. There was no statistical significance to be found (P > 0.05) between the two methods. By linear correlation and regression analysis, a positive correlation was found between the two methods (r = 0.8942, b = 0.8154). The handheld non-contact tonometer has the same accuracy and reliability of measurement of intraocular pressure comparing with Goldmann applanation tonometer, and it can be used in glaucoma clinic and screening.

Handheld pose tracking using vision-inertial sensors with occlusion handling

Science.gov (United States)

Li, Juan; Slembrouck, Maarten; Deboeverie, Francis; Bernardos, Ana M.; Besada, Juan A.; Veelaert, Peter; Aghajan, Hamid; Casar, José R.; Philips, Wilfried

2016-07-01

Tracking of a handheld device's three-dimensional (3-D) position and orientation is fundamental to various application domains, including augmented reality (AR), virtual reality, and interaction in smart spaces. Existing systems still offer limited performance in terms of accuracy, robustness, computational cost, and ease of deployment. We present a low-cost, accurate, and robust system for handheld pose tracking using fused vision and inertial data. The integration of measurements from embedded accelerometers reduces the number of unknown parameters in the six-degree-of-freedom pose calculation. The proposed system requires two light-emitting diode (LED) markers to be attached to the device, which are tracked by external cameras through a robust algorithm against illumination changes. Three data fusion methods have been proposed, including the triangulation-based stereo-vision system, constraint-based stereo-vision system with occlusion handling, and triangulation-based multivision system. Real-time demonstrations of the proposed system applied to AR and 3-D gaming are also included. The accuracy assessment of the proposed system is carried out by comparing with the data generated by the state-of-the-art commercial motion tracking system OptiTrack. Experimental results show that the proposed system has achieved high accuracy of few centimeters in position estimation and few degrees in orientation estimation.

Radiation safety evaluation of a hand-held, battery operated image intensifier

International Nuclear Information System (INIS)

Wilson, O.J.; Young, B.F.

1987-01-01

A portable, hand-held, fluoroscopic unit intended for medical and industrial use was tested to verify the claim of the manufacturers that the radiation doses to the patient and user are low, and comparable to those received from standard radiographic procedures. The first claim was substantiated but not the second. A number of concerns arising from the use of this unit are discussed

77 FR 25150 - GPS Satellite Simulator Working Group; Notice of Meeting

Science.gov (United States)

2012-04-27

... DEPARTMENT OF DEFENSE Department of the Air Force GPS Satellite Simulator Working Group; Notice of Meeting AGENCY: The United States Air Force, DoD. ACTION: Amending GPS Simulator Working group Meeting Notice. SUMMARY: We are requesting to amend the date of the GPS Simulator Working group meeting notice...

77 FR 25510 - GPS Funds I, et al.; Notice of Application

Science.gov (United States)

2012-04-30

...] GPS Funds I, et al.; Notice of Application April 24, 2012. AGENCY: Securities and Exchange Commission... the Act to invest in certain financial instruments. Applicants: GPS Funds I, GPS Funds II (each a.... FOR FURTHER INFORMATION CONTACT: Laura L. Solomon, Senior Counsel, at (202) 551-6915 or Daniele...

How do GPs recognize needs for palliative care in their patients?

NARCIS (Netherlands)

Claessen, S.J.; Francke, A.L.; Deliens, L.

2012-01-01

Aim: The aim of this study was to explore how GPs in the Netherlands recognize patients’ needs for palliative care. Methods: We conducted qualitative semi-structured interviews with about 25 GPs. These GPs were interviewed about recognition of the needs for palliative care in their patients and how

Using GPS to Detect Imminent Tsunamis

Science.gov (United States)

Song, Y. Tony

2009-01-01

A promising method of detecting imminent tsunamis and estimating their destructive potential involves the use of Global Positioning System (GPS) data in addition to seismic data. Application of the method is expected to increase the reliability of global tsunami-warning systems, making it possible to save lives while reducing the incidence of false alarms. Tsunamis kill people every year. The 2004 Indian Ocean tsunami killed about 230,000 people. The magnitude of an earthquake is not always a reliable indication of the destructive potential of a tsunami. The 2004 Indian Ocean quake generated a huge tsunami, while the 2005 Nias (Indonesia) quake did not, even though both were initially estimated to be of the similar magnitude. Between 2005 and 2007, five false tsunami alarms were issued worldwide. Such alarms result in negative societal and economic effects. GPS stations can detect ground motions of earthquakes in real time, as frequently as every few seconds. In the present method, the epicenter of an earthquake is located by use of data from seismometers, then data from coastal GPS stations near the epicenter are used to infer sea-floor displacements that precede a tsunami. The displacement data are used in conjunction with local topographical data and an advanced theory to quantify the destructive potential of a tsunami on a new tsunami scale, based on the GPS-derived tsunami energy, much like the Richter Scale used for earthquakes. An important element of the derivation of the advanced theory was recognition that horizontal sea-floor motions contribute much more to generation of tsunamis than previously believed. The method produces a reliable estimate of the destructive potential of a tsunami within minutes typically, well before the tsunami reaches coastal areas. The viability of the method was demonstrated in computational tests in which the method yielded accurate representations of three historical tsunamis for which well-documented ground

Acropora Spatial Survey Data of the Upper Florida Keys National Marine Sanctuary 2005 -2007 (NODC Accession 0046934)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Presence or absence of acroporid corals marked by handheld GPS during snorkel or tow surveys of shallow water (5m) reef habitats in the Upper Florida Keys National...

Climatology of GPS signal loss observed by Swarm satellites

Directory of Open Access Journals (Sweden)

C. Xiong

2018-04-01

Full Text Available By using 3-year global positioning system (GPS measurements from December 2013 to November 2016, we provide in this study a detailed survey on the climatology of the GPS signal loss of Swarm onboard receivers. Our results show that the GPS signal losses prefer to occur at both low latitudes between ±5 and ±20° magnetic latitude (MLAT and high latitudes above 60° MLAT in both hemispheres. These events at all latitudes are observed mainly during equinoxes and December solstice months, while totally absent during June solstice months. At low latitudes the GPS signal losses are caused by the equatorial plasma irregularities shortly after sunset, and at high latitude they are also highly related to the large density gradients associated with ionospheric irregularities. Additionally, the high-latitude events are more often observed in the Southern Hemisphere, occurring mainly at the cusp region and along nightside auroral latitudes. The signal losses mainly happen for those GPS rays with elevation angles less than 20°, and more commonly occur when the line of sight between GPS and Swarm satellites is aligned with the shell structure of plasma irregularities. Our results also confirm that the capability of the Swarm receiver has been improved after the bandwidth of the phase-locked loop (PLL widened, but the updates cannot radically avoid the interruption in tracking GPS satellites caused by the ionospheric plasma irregularities. Additionally, after the PLL bandwidth increased larger than 0.5 Hz, some unexpected signal losses are observed even at middle latitudes, which are not related to the ionospheric plasma irregularities. Our results suggest that rather than 1.0 Hz, a PLL bandwidth of 0.5 Hz is a more suitable value for the Swarm receiver.

Climatology of GPS signal loss observed by Swarm satellites

Science.gov (United States)

Xiong, Chao; Stolle, Claudia; Park, Jaeheung

2018-04-01

By using 3-year global positioning system (GPS) measurements from December 2013 to November 2016, we provide in this study a detailed survey on the climatology of the GPS signal loss of Swarm onboard receivers. Our results show that the GPS signal losses prefer to occur at both low latitudes between ±5 and ±20° magnetic latitude (MLAT) and high latitudes above 60° MLAT in both hemispheres. These events at all latitudes are observed mainly during equinoxes and December solstice months, while totally absent during June solstice months. At low latitudes the GPS signal losses are caused by the equatorial plasma irregularities shortly after sunset, and at high latitude they are also highly related to the large density gradients associated with ionospheric irregularities. Additionally, the high-latitude events are more often observed in the Southern Hemisphere, occurring mainly at the cusp region and along nightside auroral latitudes. The signal losses mainly happen for those GPS rays with elevation angles less than 20°, and more commonly occur when the line of sight between GPS and Swarm satellites is aligned with the shell structure of plasma irregularities. Our results also confirm that the capability of the Swarm receiver has been improved after the bandwidth of the phase-locked loop (PLL) widened, but the updates cannot radically avoid the interruption in tracking GPS satellites caused by the ionospheric plasma irregularities. Additionally, after the PLL bandwidth increased larger than 0.5 Hz, some unexpected signal losses are observed even at middle latitudes, which are not related to the ionospheric plasma irregularities. Our results suggest that rather than 1.0 Hz, a PLL bandwidth of 0.5 Hz is a more suitable value for the Swarm receiver.

Diagnosing skin disease in primary care: a qualitative study of GPs' approaches.

Science.gov (United States)

Rübsam, Marie-Luise; Esch, Maximilian; Baum, Erika; Bösner, Stefan

2015-10-01

Skin diseases are a common reason for consulting a GP. This regular occurrence happens despite most GPs' lack of knowledge and training in skin disease. We aimed to explore different diagnostic approaches of GPs in patients presenting with a dermatological problem. In addition, we aimed to identify strategies used by GPs to handle diagnostic uncertainty in these patients. We conducted interviews (20-40 minutes) with 14 GPs using a semi-structured guideline. Recalling encounters with patients with skin disease, GPs described their individual diagnostic strategies. Interviews were taped and transcribed verbatim. Qualitative analysis was conducted by two independent raters using a deductive-inductive approach. We identified several aspects of a complex decision-making process in GPs' diagnostic management of patients with dermatological problems. In the general diagnostic workup, GPs used a broad spectrum of different strategies such as spot diagnosis, stepwise refinement, pattern recognition trigger or test of treatment. GPs reduced diagnostic uncertainty through the identification of red flags, the application of the test of time, therapeutic trials and asking for further advice, including patient referral. GPs encounter a broad range of dermatological problems in their daily work using a variety of strategies in the workup of these patients. However, in a significant number of patients, there remains diagnostic uncertainty that is mainly reduced by specialist referral. Regular training in the diagnosis and treatment of common dermatological diseases should be offered to all GPs. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The covariance of GPS coordinates and frames

International Nuclear Information System (INIS)

Lachieze-Rey, Marc

2006-01-01

We explore, in the general relativistic context, the properties of the recently introduced global positioning system (GPS) coordinates, as well as those of the associated frames and coframes that they define. We show that they are covariant and completely independent of any observer. We show that standard spectroscopic and astrometric observations allow any observer to measure (i) the values of the GPS coordinates at his position (ii) the components of his 4-velocity and (iii) the components of the metric in the GPS frame. This provides this system with a unique value both for conceptual discussion (no frame dependence) and for practical use (involved quantities are directly measurable): localization, motion monitoring, astrometry, cosmography and tests of gravitation theories. We show explicitly, in the general relativistic context, how an observer may estimate his position and motion, and reconstruct the components of the metric. This arises from two main results: the extension of the velocity fields of the probes to the whole (curved) spacetime, and the identification of the components of the observer's velocity in the GPS frame with the (inversed) observed redshifts of the probes. Specific cases (non-relativistic velocities, Minkowski and Friedmann-Lemaitre spacetimes, geodesic motions) are studied in detail

Design about position and display of GPS based on singlechip

Directory of Open Access Journals (Sweden)

WU Dongdong

2016-02-01

Full Text Available GPS is used in ships,vehicles,aircraft and other moving objects.GPS also has the important application in vehicle monitoring system.However,with the expansion of the specialized functions of GPS,its high cost makes so many ordinary consumers unbearable.This paper proposes a simple design of GPS based on singlechip.The design Improves the basic utility functions of system and adds the speed and mileage measurement.GPS module uses the differential technology to improve the positioning accuracy.Therefore,the navigation device is compact,easy to carry and of high precision positioning.Through getting the data of 3D coordinates from the observation point and the factor of position accuracy,the average of which is less than five,indicating that the position accuracy can be improved by differential technology to achieve the desired range.At last,the feasibility of this design is verified through the current data tested in the outdoors.

GPs and end of life decisions : views and experiences

OpenAIRE

Abela, Jurgen

2015-01-01

The views and experiences of GPs with respect to end of life (EoL) care are seldom addressed. The aim of this article is to better understand this aspect of care. A cross-sectional survey of all doctors in the country was designed and set up. The overall response was 396 (39.7%), 160 of which were GPs. 28.7% of GPs received no formal training in palliative medicine. 89.8% of respondents declared that their religion was important in EoL care. 45.3% agreed with the right of a patient to decide ...

Detection of fecal contamination on beef meat surfaces using handheld fluorescence imaging device (HFID)

Science.gov (United States)

Oh, Mirae; Lee, Hoonsoo; Cho, Hyunjeong; Moon, Sang-Ho; Kim, Eun-Kyung; Kim, Moon S.

2016-05-01

Current meat inspection in slaughter plants, for food safety and quality attributes including potential fecal contamination, is conducted through by visual examination human inspectors. A handheld fluorescence-based imaging device (HFID) was developed to be an assistive tool for human inspectors by highlighting contaminated food and food contact surfaces on a display monitor. It can be used under ambient lighting conditions in food processing plants. Critical components of the imaging device includes four 405-nm 10-W LEDs for fluorescence excitation, a charge-coupled device (CCD) camera, optical filter (670 nm used for this study), and Wi-Fi transmitter for broadcasting real-time video/images to monitoring devices such as smartphone and tablet. This study aimed to investigate the effectiveness of HFID in enhancing visual detection of fecal contamination on red meat, fat, and bone surfaces of beef under varying ambient luminous intensities (0, 10, 30, 50 and 70 foot-candles). Overall, diluted feces on fat, red meat and bone areas of beef surfaces were detectable in the 670-nm single-band fluorescence images when using the HFID under 0 to 50 foot-candle ambient lighting.

A BODIPY-Based Fluorescent Probe to Visually Detect Phosgene: Toward the Development of a Handheld Phosgene Detector.

Science.gov (United States)

Sayar, Melike; Karakuş, Erman; Güner, Tuğrul; Yildiz, Busra; Yildiz, Umit Hakan; Emrullahoğlu, Mustafa

2018-03-02

A boron-dipyrromethene (BODIPY)-based fluorescent probe with a phosgene-specific reactive motif shows remarkable selectivity toward phosgene, in the presence of which the nonfluorescent dye rapidly transforms into a new structure and induces a fluorescent response clearly observable to the naked eye under ultraviolet light. Given that dynamic, a prototypical handheld phosgene detector with a promising sensing capability that expedites the detection of gaseous phosgene without sophisticated instrumentation was developed. The proposed method using the handheld detector involves a rapid response period suitable for issuing early warnings during emergency situations. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficacy of Handheld Electronic Visual Supports to Enhance Vocabulary in Children with ASD

Science.gov (United States)

Ganz, Jennifer B.; Boles, Margot B.; Goodwyn, Fara D.; Flores, Margaret M.

2014-01-01

Although electronic tools such as handheld computers have become increasingly common throughout society, implementation of such tools to improve skills in individuals with intellectual and developmental disabilities has lagged in the professional literature. However, the use of visual scripts for individuals with disabilities, particularly those…

Research in Application of Geodetic GPS Receivers in Time Synchronization

Science.gov (United States)

Zhang, Q.; Zhang, P.; Sun, Z.; Wang, F.; Wang, X.

2018-04-01

In recent years, with the development of satellite orbit and clock parameters accurately determining technology and the popularity of geodetic GPS receivers, Common-View (CV) which proposed in 1980 by Allan has gained widespread application and achieved higher accuracy time synchronization results. GPS Common View (GPS CV) is the technology that based on multi-channel geodetic GPS receivers located in different place and under the same common-view schedule to receiving same GPS satellite signal at the same time, and then calculating the time difference between respective local receiver time and GPST by weighted theory, we will obtain the difference between above local time of receivers that installed in different station with external atomic clock. Multi-channel geodetic GPS receivers have significant advantages such as higher stability, higher accuracy and more common-view satellites in long baseline time synchronization application over the single-channel geodetic GPS receivers. At present, receiver hardware delay and surrounding environment influence are main error factors that affect the accuracy of GPS common-view result. But most error factors will be suppressed by observation data smoothing and using of observation data from different satellites in multi-channel geodetic GPS receiver. After the SA (Selective Availability) cancellation, using a combination of precise satellite ephemeris, ionospheric-free dual-frequency P-code observations and accurately measuring of receiver hardware delay, we can achieve time synchronization result on the order of nanoseconds (ns). In this paper, 6 days observation data of two IGS core stations with external atomic clock (PTB, USNO distance of two stations about 6000 km) were used to verify the GPS common-view theory. Through GPS observation data analysis, there are at least 2-4 common-view satellites and 5 satellites in a few tracking periods between two stations when the elevation angle is 15°, even there will be at least

RESEARCH IN APPLICATION OF GEODETIC GPS RECEIVERS IN TIME SYNCHRONIZATION

Directory of Open Access Journals (Sweden)

Q. Zhang

2018-04-01

Full Text Available In recent years, with the development of satellite orbit and clock parameters accurately determining technology and the popularity of geodetic GPS receivers, Common-View (CV which proposed in 1980 by Allan has gained widespread application and achieved higher accuracy time synchronization results. GPS Common View (GPS CV is the technology that based on multi-channel geodetic GPS receivers located in different place and under the same common-view schedule to receiving same GPS satellite signal at the same time, and then calculating the time difference between respective local receiver time and GPST by weighted theory, we will obtain the difference between above local time of receivers that installed in different station with external atomic clock. Multi-channel geodetic GPS receivers have significant advantages such as higher stability, higher accuracy and more common-view satellites in long baseline time synchronization application over the single-channel geodetic GPS receivers. At present, receiver hardware delay and surrounding environment influence are main error factors that affect the accuracy of GPS common-view result. But most error factors will be suppressed by observation data smoothing and using of observation data from different satellites in multi-channel geodetic GPS receiver. After the SA (Selective Availability cancellation, using a combination of precise satellite ephemeris, ionospheric-free dual-frequency P-code observations and accurately measuring of receiver hardware delay, we can achieve time synchronization result on the order of nanoseconds (ns. In this paper, 6 days observation data of two IGS core stations with external atomic clock (PTB, USNO distance of two stations about 6000 km were used to verify the GPS common-view theory. Through GPS observation data analysis, there are at least 2–4 common-view satellites and 5 satellites in a few tracking periods between two stations when the elevation angle is 15°, even

A study of cladding technology on tube wall surface by a hand-held laser torch

International Nuclear Information System (INIS)

Terada, Takaya; Nishimura, Akihiko; Oka, Kiyoshi; Moriyama, Taku; Matsuda, Hiroyasu

2015-01-01

New maintenance technique was proposed using a hand-held laser torch for aging chemical plants and power plants. The hand-held laser torch was specially designed to be able to access limited tubular space in various cases. A composite-type optical fiberscope was composed of a center fiber for beam delivery and surrounded fibers for visible image delivery. Laser irradiation on a work pieces with the best accuracy of filler wire was carried out. And, we found that the optimized wire-feed speed was 2 mm/s in laser cladding. We succeeded to make a line clad on the inner wall of 23 mm tube. This technique was discussed to be applied to the maintenance for cracks or corrosions of tubes in various harsh environments. (author)

Evolving Consumption Patterns of Various Information Media via Handheld Mobile Devices

Directory of Open Access Journals (Sweden)

Nitza Geri

2015-06-01

Full Text Available This study examines diverse information media in order to identify those formats that are most suitable for consumption via handheld mobile devices, namely, smartphones and tablets. The preferences of the users are measured objectively by analyzing actual data of their relative use of handheld mobile devices and personal computing (PC desktop devices, including laptops and notebooks, for consumption of information presented in various formats. Our findings are based on Google Analytics pageview data of five course Websites during a period of three semesters, by 11,557 undergraduate students. M-learning contexts were chosen, since in a learning environment the interests of information providers (i.e., the instructors are in accord with those of the information consumers (i.e., the students, whereas in commercial settings there may be conflicts of interests. Our findings demonstrate that although about 90% of the pageviews were via PC devices, the rate of smartphone use for consuming learning content in diverse information media is gradually increasing as time goes by, whereas the rate of tablet use for these purposes is stagnant. The most promising direction for smartphone development, emanating from the findings, is online video content.

Hand-held indirect calorimeter offers advantages compared with prediction equations, in a group of overweight women, to determine resting energy expenditures and estimated total energy expenditures during research screening.

Science.gov (United States)

Spears, Karen E; Kim, Hyunsook; Behall, Kay M; Conway, Joan M

2009-05-01

To compare standardized prediction equations to a hand-held indirect calorimeter in estimating resting energy and total energy requirements in overweight women. Resting energy expenditure (REE) was measured by hand-held indirect calorimeter and calculated by prediction equations Harris-Benedict, Mifflin-St Jeor, World Health Organization/Food and Agriculture Organization/United Nations University (WHO), and Dietary Reference Intakes (DRI). Physical activity level, assessed by questionnaire, was used to estimate total energy expenditure (TEE). Subjects (n=39) were female nonsmokers older than 25 years of age with body mass index more than 25. Repeated measures analysis of variance, Bland-Altman plot, and fitted regression line of difference. A difference within +/-10% of two methods indicated agreement. Significant proportional bias was present between hand-held indirect calorimeter and prediction equations for REE and TEE (Pvalues and underestimated at higher values. Mean differences (+/-standard error) for REE and TEE between hand-held indirect calorimeter and Harris-Benedict were -5.98+/-46.7 kcal/day (P=0.90) and 21.40+/-75.7 kcal/day (P=0.78); between hand-held indirect calorimeter and Mifflin-St Jeor were 69.93+/-46.7 kcal/day (P=0.14) and 116.44+/-75.9 kcal/day (P=0.13); between hand-held indirect calorimeter and WHO were -22.03+/-48.4 kcal/day (P=0.65) and -15.8+/-77.9 kcal/day (P=0.84); and between hand-held indirect calorimeter and DRI were 39.65+/-47.4 kcal/day (P=0.41) and 56.36+/-85.5 kcal/day (P=0.51). Less than 50% of predictive equation values were within +/-10% of hand-held indirect calorimeter values, indicating poor agreement. A significant discrepancy between predicted and measured energy expenditure was observed. Further evaluation of hand-held indirect calorimeter research screening is needed.

Asset Management of Roadway Signs Through Advanced Technology

Science.gov (United States)

2003-06-01

This research project aims to ease the process of Roadway Sign asset management. The project utilized handheld computer and global positioning system (GPS) technology to capture sign location data along with a timestamp. This data collection effort w...

Hiking and biking with GPS: The Canadian perspective

Science.gov (United States)

Vaníček, Petr

The paper attempts to review and put into perspective the findings of a recent by-invitation-only workshop on GPS held in Ottawa. The workshop brought together both GPS-information suppliers and consumers coming from all walks of life. Some unique exchanges of views took place which are worth bringing to the attention of the geodetic community.

Handheld Multi-Gas Meters Assessment Report

Energy Technology Data Exchange (ETDEWEB)

Williams, Gustavious [Brigham Young Univ., Provo, UT (United States); Wald-Hopkins, Mark David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Obrey, Stephen J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Akhadov, Valida Dushdurova [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-06-27

Handheld multi-gas meters (MGMs) are equipped with sensors to monitor oxygen (O2) levels and additional sensors to detect the presence of combustible or toxic gases in the environment. This report is limited to operational response-type MGMs that include at least four different sensors. These sensors can vary by type and by the monitored chemical. In real time, the sensors report the concentration of monitored gases in the atmosphere near the MGM. In April 2016 the System Assessment and Validation for Emergency Responders (SAVER) Program conducted an operationally-oriented assessment of MGMs. Five MGMs were assessed by emergency responders. The criteria and scenarios used in this assessment were derived from the results of a focus group of emergency responders with experience in using MGMs. The assessment addressed 16 evaluation criteria in four SAVER categories: Usability, Capability, Maintainability, and Deployability.

Pandora's electronic box: GPs reflect upon email communication with their patients

Directory of Open Access Journals (Sweden)

Felicity Goodyear-Smith

2005-11-01

Conclusion Study sample closely mirrored current NZ GP population. Although few GPs emailed with patients, many might once barriers are addressed. GPs had a collective view of the appropriate boundaries for email communication, routine tasks and the transmission of information. GPs would encourage professional debate regarding guidelines for good practice, managing demand and remuneration.

Anti-Jam GPS Antennas for Wearable Dismounted Soldier Navigation Systems

Science.gov (United States)

2016-06-01

GPS antenna, the Novatel GAJT-700M/ L CRPA is currently being considered, as shown in Fig. 6. Fig. 6 A basic 7-element CRPA (right) compared with a...ARL-TR-7670 ● JUNE 2016 US Army Research Laboratory Anti-Jam GPS Antennas for Wearable Dismounted Soldier Navigation Systems...longer needed. Do not return it to the originator. ARL-TR-7670 ● JUNE 2016 US Army Research Laboratory Anti-Jam GPS Antennas for

Advanced sampling techniques for hand-held FT-IR instrumentation

Science.gov (United States)

Arnó, Josep; Frunzi, Michael; Weber, Chris; Levy, Dustin

2013-05-01

FT-IR spectroscopy is the technology of choice to identify solid and liquid phase unknown samples. The challenging ConOps in emergency response and military field applications require a significant redesign of the stationary FT-IR bench-top instruments typically used in laboratories. Specifically, field portable units require high levels of resistance against mechanical shock and chemical attack, ease of use in restrictive gear, extreme reliability, quick and easy interpretation of results, and reduced size. In the last 20 years, FT-IR instruments have been re-engineered to fit in small suitcases for field portable use and recently further miniaturized for handheld operation. This article introduces the HazMatID™ Elite, a FT-IR instrument designed to balance the portability advantages of a handheld device with the performance challenges associated with miniaturization. In this paper, special focus will be given to the HazMatID Elite's sampling interfaces optimized to collect and interrogate different types of samples: accumulated material using the on-board ATR press, dispersed powders using the ClearSampler™ tool, and the touch-to-sample sensor for direct liquid sampling. The application of the novel sample swipe accessory (ClearSampler) to collect material from surfaces will be discussed in some detail. The accessory was tested and evaluated for the detection of explosive residues before and after detonation. Experimental results derived from these investigations will be described in an effort to outline the advantages of this technology over existing sampling methods.

Xsense: using nanotechnology to combine detection methods for high sensitivity handheld explosives detectors

DEFF Research Database (Denmark)

Schmidt, Michael Stenbæk; Kostesha, Natalie; Bosco, Filippo

2010-01-01

In an effort to produce a handheld explosives sensor the Xsense project has been initiated at the Technical University of Denmark in collaboration with a number of partners. Using micro- and nano technological approaches it will be attempted to integrate four detection principles into a single de...

Standard guide to In-Plant performance evaluation of Hand-Held SNM monitors

CERN Document Server

American Society for Testing and Materials. Philadelphia

1999-01-01

1.1 This guide is one of a series on the application and evaluation of special nuclear material (SNM) monitors. Other guides in the series are listed in Section 2, and the relationship of in-plant performance evaluation to other procedures described in the series is illustrated in Fig. 1. Hand-held SNM monitors are described in of Guide C1112, and performance criteria illustrating their capabilities can be found in Appendix X1. 1.2 The purpose of this guide to in-plant performance evaluation is to provide a comparatively rapid procedure to verify that a hand-held SNM monitor performs as expected for detecting SNM or alternative test sources or to disclose the need for repair. The procedure can be used as a routine operational evaluation or it can be used to verify performance after a monitor is calibrated. 1.3 In-plant performance evaluations are more comprehensive than daily functional tests. They take place less often, at intervals ranging from weekly to once every three months, and derive their result fr...

Using GPS to evaluate productivity and performance of forest machine systems

Science.gov (United States)

Steven E. Taylor; Timothy P. McDonald; Matthew W. Veal; Ton E. Grift

2001-01-01

This paper reviews recent research and operational applications of using GPS as a tool to help monitor the locations, travel patterns, performance, and productivity of forest machines. The accuracy of dynamic GPS data collected on forest machines under different levels of forest canopy is reviewed first. Then, the paper focuses on the use of GPS for monitoring forest...

Mapping the Coastline Limits of the Mexican State Sinaloa Using GPS

Science.gov (United States)

Vazquez, G. E.

2007-12-01

This research work presents the delimitation of the coastline limits of Sinaloa (one of the richest states of northwestern Mexico). In order to achieve this big task, it was required to use GPS (Global Positioning System) together with leveling spirit measurements. Based on the appropriate selection of the cited measurement techniques, the objective was to map the Sinaloa's state coastline to have the cartography of approximate 1600 km of littoral. The GPS measurements were performed and referred with respect to a GPS network located across the state. This GPS network consists of at least one first-order-site at each of the sixteen counties that constitute the state, and three to four second-order-sites of the ten counties of the state surrounded by sea. The leveling spirit measurements were referred to local benchmarks pre-established by the Mexican agency SEMARNAT (SEcretaría Del Medio Ambiente y Recursos NATurales). Within the main specifications of the GPS measurements and equipment, we used geodetic-dual-frequency GPS receivers in kinematic mode for both base stations (first and second order sites of the GPS state network) and rover stations (points forming the state littoral) with 5-sec log-rate interval and 10 deg cut-off angle. The GPS data processing was performed using the commercial software Trimble Geomatics Office (TGO) with Double Differences (DD) in post-processing mode. To this point, the field measurements had been totally covered including the cartography (scale 1:1000) and this includes the specifications and appropriate labeling according to the Mexican norm NOM-146-SEMARNAT-2005.

On the Realistic Stochastic Model of GPS Observables: Implementation and Performance

Science.gov (United States)

Zangeneh-Nejad, F.; Amiri-Simkooei, A. R.; Sharifi, M. A.; Asgari, J.

2015-12-01

High-precision GPS positioning requires a realistic stochastic model of observables. A realistic GPS stochastic model of observables should take into account different variances for different observation types, correlations among different observables, the satellite elevation dependence of observables precision, and the temporal correlation of observables. Least-squares variance component estimation (LS-VCE) is applied to GPS observables using the geometry-based observation model (GBOM). To model the satellite elevation dependent of GPS observables precision, an exponential model depending on the elevation angles of the satellites are also employed. Temporal correlation of the GPS observables is modelled by using a first-order autoregressive noise model. An important step in the high-precision GPS positioning is double difference integer ambiguity resolution (IAR). The fraction or percentage of success among a number of integer ambiguity fixing is called the success rate. A realistic estimation of the GNSS observables covariance matrix plays an important role in the IAR. We consider the ambiguity resolution success rate for two cases, namely a nominal and a realistic stochastic model of the GPS observables using two GPS data sets collected by the Trimble R8 receiver. The results confirm that applying a more realistic stochastic model can significantly improve the IAR success rate on individual frequencies, either on L1 or on L2. An improvement of 20% was achieved to the empirical success rate results. The results also indicate that introducing the realistic stochastic model leads to a larger standard deviation for the baseline components by a factor of about 2.6 on the data sets considered.

GPS IPW as a Meteorological Parameter and Climate Global Change Indicator

Science.gov (United States)

Kruczyk, M.; Liwosz, T.

2011-12-01

Paper focuses on comprehensive investigation of the GPS derived IPW (Integrated Precipitable Water, also IWV) as a geophysical tool. GPS meteorology is now widely acknowledged indirect method of atmosphere sensing. First we demonstrate GPS IPW quality. Most thorough inter-technique comparisons of directly measured IPW are attainable only for some observatories (note modest percentage of GPS stations equipped with meteorological devices). Nonetheless we have managed to compare IPW series derived from GPS tropospheric solutions (ZTD mostly from IGS and EPN solutions) and some independent techniques. IPW values from meteorological sources we used are: radiosoundings, sun photometer and input fields of numerical weather prediction model. We can treat operational NWP models as meteorological database within which we can calculate IWV for all GPS stations independently from network of direct measurements (COSMO-LM model maintained by Polish Institute of Meteorology and Water Management was tried). Sunphotometer (CIMEL-318, Central Geophysical Observatory IGF PAS, Belsk, Poland) data seems the most genuine source - so we decided for direct collocation of GPS measurements and sunphotometer placing permanent GPS receiver on the roof of Belsk Observatory. Next we analyse IPW as geophysical parameter: IPW demonstrates some physical effects evoked by station location (height and series correlation coefficient as a function of distance) and weather patterns like dominant wind directions (in case of neighbouring stations). Deficiency of surface humidity data to model IPW is presented for different climates. This inadequacy and poor humidity data representation in NWP model extremely encourages investigating information exchange potential between Numerical Model and GPS network. The second and most important aspect of this study concerns long series of IPW (daily averaged) which can serve as climatological information indicator (water vapour role in climate system is hard to

Strength Measurements in Acute Hamstring Injuries: Intertester Reliability and Prognostic Value of Handheld Dynamometry

NARCIS (Netherlands)

Reurink, Gustaaf; Goudswaard, Gert Jan; Moen, Maarten H.; Tol, Johannes L.; Verhaar, Jan A. N.; Weir, Adam

2016-01-01

Study Design Cohort study, repeated measures. Background Although hamstring strength measurements are used for assessing prognosis and monitoring recovery after hamstring injury, their actual clinical relevance has not been established. Handheld dynamometry (HHD) is a commonly used method of

GPS sekošanas sistēma

OpenAIRE

Striževskis, Andrejs

2011-01-01

Šajā darbā ir izskatītas GPS sekošanas iespējas privātās lietošanas sfērā, aprakstītas kartogrāfijas un navigācijas teorētisko pamatu izvēlētās nodaļas un piedāvāts bezmaksas risinājums, kas dod iespēju izmantot sekošanai GPS ierīces ar datora palīdzību un interneta pieslēgumu bez papildus servisiem, kā arī veidot tam nolūkam navigācijas kartes, piesaistot rastra attēlus Zemes ģeogrāfisko koordinātu sistēmai ar polinomiālās transformācijas palīdzību. Atslēgvārdi: GPS sekošana, GIS, navigāc...

Epidemiology of Handheld Cell Phone Use While Driving: A Study from a South Indian City.

Science.gov (United States)

Majgi, Sumanth Mallikarjuna; AiswaryaLakshmi, A S

2018-01-01

Using cell phones while driving contribute to distractions which can potentially cause minor or major road traffic injuries and also stress among other drivers. With this background, the study was done to ascertain the proportion of handheld cell phone use while driving among road users in Mysore city and also patterns of the use by the day of week, type of road, and type of vehicle. The study was conducted in Mysore, Karnataka, India. Four stretches of roads were observed thrice daily for 1 week. The total number of vehicles passing through the stretch and the number and characteristics of drivers using hand-held cell was noted. Pearson's Chi-square test was used to ascertain the significance of the difference in proportions. The overall proportion of cell phone users was calculated as 1.41/100 vehicles. The observed use of handheld cell phones was 1.78 times higher on nonbusy roads than busy roads ( Χ 2 = 25.79, P phone users were driving a two wheeler, the proportion being 50.5% in busy roads, and 67% in nonbusy roads. There was no difference in the proportion of cell phone use by time of the day or across different days of the week. The proportion of drivers who use cell phones is found to be relatively lower, and use of cell phones was higher on nonbusy roads.

Balancing fast-rotating parts of hand-held machine drive

Science.gov (United States)

Korotkov, V. S.; Sicora, E. A.; Nadeina, L. V.; Yongzheng, Wang

2018-03-01

The article considers the issues related to the balancing of fast rotating parts of the hand-held machine drive including a wave transmission with intermediate rolling elements, which is constructed on the basis of the single-phase collector motor with a useful power of 1 kW and a nominal rotation frequency of 15000 rpm. The forms of balancers and their location are chosen. The method of balancing is described. The scheme for determining of residual unbalance in two correction planes is presented. Measurement results are given in tables.

A Mobile GPS Application: Mosque Tracking with Prayer Time Synchronization

Science.gov (United States)

Hashim, Rathiah; Ikhmatiar, Mohammad Sibghotulloh; Surip, Miswan; Karmin, Masiri; Herawan, Tutut

Global Positioning System (GPS) is a popular technology applied in many areas and embedded in many devices, facilitating end-users to navigate effectively to user's intended destination via the best calculated route. The ability of GPS to track precisely according to coordinates of specific locations can be utilized to assist a Muslim traveler visiting or passing an unfamiliar place to find the nearest mosque in order to perform his prayer. However, not many techniques have been proposed for Mosque tracking. This paper presents the development of GPS technology in tracking the nearest mosque using mobile application software embedded with the prayer time's synchronization system on a mobile application. The prototype GPS system developed has been successfully incorporated with a map and several mosque locations.

An Advanced Data Warehouse for Integrating Large Sets of GPS Data

DEFF Research Database (Denmark)

Andersen, Ove; Krogh, Benjamin Bjerre; Thomsen, Christian

2014-01-01

GPS data recorded from driving vehicles is available from many sources and is a very good data foundation for answering traffic related queries. However, most approaches so far have not considered combining GPS data from many sources into a single data warehouse. Further, the integration of GPS...... data with fuel consumption data (from the so-called CAN bus in the vehicles) and weather data has not been done. In this paper, we propose a data warehouse design for handling GPS data, fuel consumption data, and weather data. The design is fully implemented in a running system using the Postgre...

GPS Time Synchronization in School-Network Cosmic Ray Detectors

Science.gov (United States)

Berns, H.-G.; Burnett, T. H.; Gran, R.; Wilkes, R. J.

2004-06-01

The QuarkNet DAQ card for school-network cosmic ray detectors provides a low-cost alternative to using standard particle and nuclear physics fast pulse electronics modules. The board, which can be produced at a cost of less than $500.00 (USD), produces trigger time and pulse edge time data for 2- to 4-fold coincidence levels via a universal RS232 serial port interface, usable with any PC. Individual detector stations, each consisting of four scintillation counter modules, front-end electronics, and a GPS receiver, produce a stream of data in form of ASCII text strings in identifiable set of formats for different functions. The card includes a low-cost GPS receiver module, which permits time-stamping event triggers to about 50 nanosecond accuracy in UTC between widely separated sites. The technique used for obtaining precise GPS time employs the 1PPS signal, which is not normally available to users of the commercial GPS module. We had the stock model slightly custom-modified to access this signal. The method for deriving time values was adapted from methods developed for the K2K long-baseline neutrino experiment. Performance of the low-cost GPS module used is compared to that of a more expensive unit with known quality.

NONLINEAR FILTER METHOD OF GPS DYNAMIC POSITIONING BASED ON BANCROFT ALGORITHM

Institute of Scientific and Technical Information of China (English)

ZHANGQin; TAOBen-zao; ZHAOChao-ying; WANGLi

2005-01-01

Because of the ignored items after linearization, the extended Kalman filter (EKF) becomes a form of suboptimal gradient descent algorithm. The emanative tendency exists in GPS solution when the filter equations are ill-posed. The deviation in the estimation cannot be avoided. Furthermore, the true solution may be lost in pseudorange positioning because the linearized pseudorange equations are partial solutions. To solve the above problems in GPS dynamic positioning by using EKF, a closed-form Kalman filter method called the two-stage algorithm is presented for the nonlinear algebraic solution of GPS dynamic positioning based on the global nonlinear least squares closed algorithm--Bancroft numerical algorithm of American. The method separates the spatial parts from temporal parts during processing the GPS filter problems, and solves the nonlinear GPS dynamic positioning, thus getting stable and reliable dynamic positioning solutions.

Transport on prescription: How can GPs contribute to the promotion of active transport?

Science.gov (United States)

Pistoll, Chance; Furler, John

2017-10-01

Active transport (ie walking, cycling, using public transport) can play a part in reducing non-communicable diseases (NCDs). Very little is known about how general practitioners (GPs) can contribute to promoting active transport. We explored GPs' ideas around active transport, and potential barriers and facilitators to its promotion in the clinical setting. Using a maximal variation sample, we conducted 10 semi-structured interviews with GPs in Victoria, Australia. The socioecological model informed data collection and analysis. The idea of active transport resonated with GPs. Limited awareness around active transport and safety concerns regarding commuter cycling were barriers to clinical promotion. GPs believed patients' health, cultural norms, socioeconomic position and access to supportive environments could facilitate participation. Future efforts should prioritise awareness of active transport among GPs. The perspectives of GPs would be valuable to policymakers, particularly in designing programs to mitigate inequalities around active transport access and use.

Vähemalt kolm hunti saavad veel GPS-kaelused / Madis Filippov

Index Scriptorium Estoniae

Filippov, Madis

2011-01-01

Esimene Eesti hunt sai kaela GPS-seadme, mis hakkab edastama teavet looma toitumise ja elupiirkonna kohta, lähiajal on plaanis samasuguse seadme paigaldamine veel vähemalt kolmele hundile. GPS loomadel

A Forward GPS Multipath Simulator Based on the Vegetation Radiative Transfer Equation Model.

Science.gov (United States)

Wu, Xuerui; Jin, Shuanggen; Xia, Junming

2017-06-05

Global Navigation Satellite Systems (GNSS) have been widely used in navigation, positioning and timing. Nowadays, the multipath errors may be re-utilized for the remote sensing of geophysical parameters (soil moisture, vegetation and snow depth), i.e., GPS-Multipath Reflectometry (GPS-MR). However, bistatic scattering properties and the relation between GPS observables and geophysical parameters are not clear, e.g., vegetation. In this paper, a new element on bistatic scattering properties of vegetation is incorporated into the traditional GPS-MR model. This new element is the first-order radiative transfer equation model. The new forward GPS multipath simulator is able to explicitly link the vegetation parameters with GPS multipath observables (signal-to-noise-ratio (SNR), code pseudorange and carrier phase observables). The trunk layer and its corresponding scattering mechanisms are ignored since GPS-MR is not suitable for high forest monitoring due to the coherence of direct and reflected signals. Based on this new model, the developed simulator can present how the GPS signals (L1 and L2 carrier frequencies, C/A, P(Y) and L2C modulations) are transmitted (scattered and absorbed) through vegetation medium and received by GPS receivers. Simulation results show that the wheat will decrease the amplitudes of GPS multipath observables (SNR, phase and code), if we increase the vegetation moisture contents or the scatters sizes (stem or leaf). Although the Specular-Ground component dominates the total specular scattering, vegetation covered ground soil moisture has almost no effects on the final multipath signatures. Our simulated results are consistent with previous results for environmental parameter detections by GPS-MR.

Horses for Courses: Designing a GPS Tracking Data Collection

DEFF Research Database (Denmark)

Reinau, Kristian Hegner; Harder, Henrik; Overgård, Christian Hansen

2014-01-01

and practical experiences from a number of GPS tracking projects into a practical guideline. Researchers can use this model as a starting point when designing a GPS tracking data collection. The authors hope that the model can constitute a first step towards the development of best practice....

Backyard Botany: Using GPS Technology in the Science Classroom

Science.gov (United States)

March, Kathryn A.

2012-01-01

Global Positioning System (GPS) technology can be used to connect students to the natural world and improve their skills in observation, identification, and classification. Using GPS devices in the classroom increases student interest in science, encourages team-building skills, and improves biology content knowledge. Additionally, it helps…

Application of GPS in a high precision engineering survey network

International Nuclear Information System (INIS)

Ruland, R.; Leick, A.

1985-04-01

A GPS satellite survey was carried out with the Macrometer to support construction at the Stanford Linear Accelerator Center (SLAC). The network consists of 16 stations of which 9 stations were part of the Macrometer network. The horizontal and vertical accuracy of the GPS survey is estimated to be 1 to 2 mm and 2 to 3 mm respectively. The horizontal accuracy of the terrestrial survey, consisting of angles and distances, equals that of the GPS survey only in the ''loop'' portion of the network. All stations are part of a precise level network. The ellipsoidal heights obtained from the GPS survey and the orthometric heights of the level network are used to compute geoid undulations. A geoid profile along the linac was computed by the National Geodetic Survey in 1963. This profile agreed with the observed geoid within the standard deviation of the GPS survey. Angles and distances were adjusted together (TERRA), and all terrestrial observations were combined with the GPS vector observations in a combination adjustment (COMB). A comparison of COMB and TERRA revealed systematic errors in the terrestrial solution. A scale factor of 1.5 ppM +- .8 ppM was estimated. This value is of the same magnitude as the over-all horizontal accuracy of both networks. 10 refs., 3 figs., 5 tabs

A New Indoor Positioning System Architecture Using GPS Signals.

Science.gov (United States)

Xu, Rui; Chen, Wu; Xu, Ying; Ji, Shengyue

2015-04-29

The pseudolite system is a good alternative for indoor positioning systems due to its large coverage area and accurate positioning solution. However, for common Global Positioning System (GPS) receivers, the pseudolite system requires some modifications of the user terminals. To solve the problem, this paper proposes a new pseudolite-based indoor positioning system architecture. The main idea is to receive real-world GPS signals, repeat each satellite signal and transmit those using indoor transmitting antennas. The transmitted GPS-like signal can be processed (signal acquisition and tracking, navigation data decoding) by the general receiver and thus no hardware-level modification on the receiver is required. In addition, all Tx can be synchronized with each other since one single clock is used in Rx/Tx. The proposed system is simulated using a software GPS receiver. The simulation results show the indoor positioning system is able to provide high accurate horizontal positioning in both static and dynamic situations.

Comparison of Wearable Optical See-through and Handheld Devices as Platform for an Augmented Reality Museum Guide

DEFF Research Database (Denmark)

Serubugo, Sule; Skantarova, Denisa; Nielsen, Lasse Kjærsgård

2017-01-01

Self-service guides are a common way of providing information about artworks exhibited in museums. Modern advances in handheld mobile applications and wearable optical see-through devices that use augmented reality offer new ways of designing museum guides that are more engaging and interactive...... than traditional self-service guides such as written descriptions or audio guides. In this study we compare wearable (smart glasses) and handheld (smartphone) devices as a platform for an augmented reality museum guide. We have developed a museum guide for both a smartphone and smart glasses that can...... of potentials of these platforms as augmented reality museum guides and suggest promising future work....

Cryospheric monitoring with new low power RTK dGPS systems

Science.gov (United States)

Martinez, K.; Hart, J. K.; Bragg, G. M.; Curry, J. S.

2017-12-01

Differential GPS is often used to measure the movement of glaciers. It requires data to be recorded at a fixed base station as well as the moving rover unit, followed by post-processing in order to compute the rover's positions. The typical dGPS units used consume considerable power and the recording times are often around one hour per reading. While this provides very precise (typically millimetre) precision it comes at a cost of power used and the data is rather large to send offsite regularly. Real-time kinematic modes of dGPS are typically used for rapid mapping and autonomous vehicles. New devices are lower cost and smaller size. They also provide a fix within a few minutes, which can be transmitted home. We describe the design, deployment and preliminary results of two tracking systems to monitor ice movement. The first used a normal GPS and Iridium satellite messaging to track the movement of a Greenland iceberg which calved from the Nattivit Apusiiat glacier (south west Greenland). This system followed the iceberg as it flowed 660 km south along the coast of Greenland. The second system was installed in Iceland to track the movement of glaciers using 2 different dGPS systems. A low power ARM Cortex M4-based controller ran Python code to schedule dGPS activity periodically and gather fixes. An Iridium short messaging unit (Rockblock) was used to transmit RTK location fixes. The aim was to experiment with the use of RTK dGPS as an alternative to recordings to measure how the glaciers responded to small scale changes in temperature and precipitation throughout the year.

Positioning performance of the NTCM model driven by GPS Klobuchar model parameters

Science.gov (United States)

Hoque, Mohammed Mainul; Jakowski, Norbert; Berdermann, Jens

2018-03-01

Users of the Global Positioning System (GPS) utilize the Ionospheric Correction Algorithm (ICA) also known as Klobuchar model for correcting ionospheric signal delay or range error. Recently, we developed an ionosphere correction algorithm called NTCM-Klobpar model for single frequency GNSS applications. The model is driven by a parameter computed from GPS Klobuchar model and consecutively can be used instead of the GPS Klobuchar model for ionospheric corrections. In the presented work we compare the positioning solutions obtained using NTCM-Klobpar with those using the Klobuchar model. Our investigation using worldwide ground GPS data from a quiet and a perturbed ionospheric and geomagnetic activity period of 17 days each shows that the 24-hour prediction performance of the NTCM-Klobpar is better than the GPS Klobuchar model in global average. The root mean squared deviation of the 3D position errors are found to be about 0.24 and 0.45 m less for the NTCM-Klobpar compared to the GPS Klobuchar model during quiet and perturbed condition, respectively. The presented algorithm has the potential to continuously improve the accuracy of GPS single frequency mass market devices with only little software modification.

Hand-held cell phone use while driving legislation and observed driver behavior among population sub-groups in the United States

OpenAIRE

Rudisill, Toni M.; Zhu, Motao

2017-01-01

Abstract Background Cell phone use behaviors are known to vary across demographic sub-groups and geographic locations. This study examined whether universal hand-held calling while driving bans were associated with lower road-side observed hand-held cell phone conversations across drivers of different ages (16–24, 25–59, ≥60 years), sexes, races (White, African American, or other), ruralities (suburban, rural, or urban), and regions (Northeast, Midwest, South, and West). Methods Data from the...

LADOTD GPS technology management plan.

Science.gov (United States)

2012-02-01

Over many years, Global Positioning System (GPS) technology has been adopted by different sections within the Louisiana : Department of Transportation and Development (DOTD), with no uniform standards for accuracy, operation, hardware, or : software....

Real-time GPS Signal Simulator

Data.gov (United States)

National Aeronautics and Space Administration — With a minimal FTE investment and no additional procurement funds, the development of a low fidelity orbital GPS Signal simulator would is possible.  This IRAD...

Effects of a Driver Cellphone Ban on Overall, Handheld, and Hands-Free Cellphone Use While Driving: New Evidence from Canada.

Science.gov (United States)

Carpenter, Christopher S; Nguyen, Hai V

2015-11-01

We provide new evidence on the effects of increasingly common driver cellphone bans on self-reported overall, handheld, and hands-free cellphone use while driving by studying Ontario, Canada, which instituted a 3-month education campaign in November 2009 followed by a binding driver cellphone ban in February 2010. Using residents of Alberta as a control group in a difference-in-differences framework, we find visual and regression-based evidence that Ontario's cellphone ban significantly reduced overall and handheld cellphone use. We also find that the policies significantly increased hands-free cellphone use. The reductions in overall and handheld use are driven exclusively by women, whereas the increases in hands-free use are much larger for men. Our results provide the first direct evidence that cellphone bans have the unintended effect of inducing substitution to hands-free devices. Copyright © 2014 John Wiley & Sons, Ltd.

GPs' attitudes, beliefs and behaviours regarding exercise for chronic knee pain: a questionnaire survey.

Science.gov (United States)

Cottrell, Elizabeth; Foster, Nadine E; Porcheret, Mark; Rathod, Trishna; Roddy, Edward

2017-06-17

The aim of this study was to investigate general practitioners' (GPs) attitudes, beliefs and behaviours regarding the use of exercise for patients with chronic knee pain (CKP) attributable to osteoarthritis. Primary care GPs in the UK. 5000 GPs, randomly selected from Binley's database, were mailed a cross-sectional questionnaire survey. GPs' attitudes and beliefs were investigated using attitude statements, and reported behaviours were identified using vignette-based questions. GPs were invited to report barriers experienced when initiating exercise with patients with CKP RESULTS: 835 (17%) GPs responded. Overall, GPs were positive about general exercise for CKP. 729 (87%) reported using exercise, of which, 538 (74%) reported that they would use both general and local (lower limb) exercises. However, only 92 (11% of all responding) GPs reported initiating exercise in ways aligning with best-evidence recommendations. 815 (98%) GPs reported barriers in using exercise for patients with CKP, most commonly, insufficient time in consultations (n=419; 51%) and insufficient expertise (n=337; 41%). While GPs' attitudes and beliefs regarding exercise for CKP were generally positive, initiation of exercise was often poorly aligned with current recommendations, and barriers and uncertainties were reported. GPs' use of exercise may be improved by addressing the key barriers of time and expertise, by developing a pragmatic approach that supports GPs to initiate individualised exercise, and/or by other professionals taking on this role. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Exploring the Limits of High Altitude GPS for Future Lunar Missions

Science.gov (United States)

Ashman, Benjamin W.; Parker, Joel J. K.; Bauer, Frank H.; Esswein, Michael

2018-01-01

An increasing number of spacecraft are relying on the Global Positioning System (GPS) for navigation at altitudes near or above the GPS constellation itself - the region known as the Space Service Volume (SSV). While the formal definition of the SSV ends at geostationary altitude, the practical limit of high-altitude space usage is not known, and recent missions have demonstrated that signal availability is sufficient for operational navigation at altitudes halfway to the moon. This paper presents simulation results based on a high-fidelity model of the GPS constellation, calibrated and validated through comparisons of simulated GPS signal availability and strength with flight data from recent high-altitude missions including the Geostationary Operational Environmental Satellite 16 (GOES-16) and the Magnetospheric Multiscale (MMS) mission. This improved model is applied to the transfer to a lunar near-rectilinear halo orbit (NRHO) of the class being considered for the international Deep Space Gateway concept. The number of GPS signals visible and their received signal strengths are presented as a function of receiver altitude in order to explore the practical upper limit of high-altitude space usage of GPS.

Rapid and automatic chemical identification of the medicinal flower buds of Lonicera plants by the benchtop and hand-held Fourier transform infrared spectroscopy

Science.gov (United States)

Chen, Jianbo; Guo, Baolin; Yan, Rui; Sun, Suqin; Zhou, Qun

2017-07-01

With the utilization of the hand-held equipment, Fourier transform infrared (FT-IR) spectroscopy is a promising analytical technique to minimize the time cost for the chemical identification of herbal materials. This research examines the feasibility of the hand-held FT-IR spectrometer for the on-site testing of herbal materials, using Lonicerae Japonicae Flos (LJF) and Lonicerae Flos (LF) as examples. Correlation-based linear discriminant models for LJF and LF are established based on the benchtop and hand-held FT-IR instruments. The benchtop FT-IR models can exactly recognize all articles of LJF and LF. Although a few LF articles are misjudged at the sub-class level, the hand-held FT-IR models are able to exactly discriminate LJF and LF. As a direct and label-free analytical technique, FT-IR spectroscopy has great potential in the rapid and automatic chemical identification of herbal materials either in laboratories or in fields. This is helpful to prevent the spread and use of adulterated herbal materials in time.

[Quality of life of women GPs in Auvergne].

Science.gov (United States)

Mathonnat, Marie Dolorès; Filloux, Isabelle; Tanguy, Gilles; Eschalier, Bénédicte; Pereira, Bruno; Vorilhon, Philippe

2013-10-01

The medical profession is feminising. In parallel, the importance of quality of life (QOL) must be addressed. Family practice needs personal investment and availability. This profession can have repercussions on womens' QOL. The objective of the study was to compare female GPs QOL to other women with the comparable socioprofessional status. The secondary objective was to study the influence of factors, such as workplace and work methods. Comparative cross-sectional study. A self-assessed questionnaire, sent by post to 394 female general practitioners in Auvergne, each was asked to recruit one woman (non-GP), with similar age and socioprofessional status. A total of 148 female GPs (37.6%) and 122 non-GPs responded. The global score of QOL was lower in the GP group, noticeably showing a poorer QOL in the relational and material areas. The professional QOL was similar between the 2 groups. The study did not find a significant difference concerning the QOL in its physical and psychological dimensions. The main negative factors influencing the QOL were: age; isolation of the occupation; living alone; and liberal occupation. Working in a rural area did not influence the QOL. The profession of GPs remains demanding, and the female GP feels a poorer QOL. Nevertheless, they seem to like their job and they feel fulfilled. The uneasiness comes essentially from the lack of free time, and from low financial income. Working in association seems to be a first step to improve the QOL of female GPs. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Radio-tracking large wilderness mammals: integration of GPS and Argos technologies

Science.gov (United States)

Schwartz, Charles C.; Arthur, Steve M.

1999-01-01

We tested 30 prototype global positioning system (GPS) radiocollars on brown bears (Ursus arctos) over a 3-year period on the Kenai Peninsula, Alaska. Collars were of 2 design types: GPS units with an Argos (Argos Data collection and Location System) satellite uplink (n = 19) and GPS units where the data were stored on board (n = 10) for retrieval at a later date. All units also contained a conventional VHF (very high frequency) transmitter and weighed 1.7 kg. GPS-Argos units obtained 10-82% of expected GPS fixes, and fix rate declined significantly (P bears varied more and were lower than fix rates for stationary collars placed in various vegetation types, suggesting that the bear, terrain, and movement all influence both fix and uplink success rate. Application of this new technology to grizzly and brown bear research and comparisons to studies with moose (Alces alces) are discussed.

Accelerometer and GPS Analysis of Trail Use and Associations With Physical Activity.

Science.gov (United States)

Tamura, Kosuke; Wilson, Jeffrey S; Puett, Robin C; Klenosky, David B; Harper, William A; Troped, Philip J

2018-03-26

Concurrent use of accelerometers and global positioning system (GPS) data can be used to quantify physical activity (PA) occurring on trails. This study examined associations of trail use with PA and sedentary behavior (SB) and quantified on trail PA using a combination of accelerometer and GPS data. Adults (N = 142) wore accelerometer and GPS units for 1-4 days. Trail use was defined as a minimum of 2 consecutive minutes occurring on a trail, based on GPS data. We examined associations between trail use and PA and SB. On trail minutes of light-intensity, moderate-intensity, and vigorous-intensity PA, and SB were quantified in 2 ways, using accelerometer counts only and with a combination of GPS speed and accelerometer data. Trail use was positively associated with total PA, moderate-intensity PA, and light-intensity PA (P GPS and accelerometer data for quantifying on trail activity may be more accurate than accelerometer data alone and is useful for classifying intensity of activities such as bicycling.

Water vapour tomography using GPS phase observations: Results from the ESCOMPTE experiment

Science.gov (United States)

Nilsson, T.; Gradinarsky, L.; Elgered, G.

2007-10-01

Global Positioning System (GPS) tomography is a technique for estimating the 3-D structure of the atmospheric water vapour using data from a dense local network of GPS receivers. Several current methods utilize estimates of slant wet delays between the GPS satellites and the receivers on the ground, which are difficult to obtain with millimetre accuracy from the GPS observations. We present results of applying a new tomographic method to GPS data from the Expériance sur site pour contraindre les modèles de pollution atmosphérique et de transport d'emissions (ESCOMPTE) experiment in southern France. This method does not rely on any slant wet delay estimates, instead it uses the GPS phase observations directly. We show that the estimated wet refractivity profiles estimated by this method is on the same accuracy level or better compared to other tomographic methods. The results are in agreement with earlier simulations, for example the profile information is limited above 4 km.

GPs' Perceptions of Cardiovascular Risk and Views on Patient Compliance

DEFF Research Database (Denmark)

Barfoed, Benedicte Marie Lind; Jarbøl, Dorte Ejg; Paulsen, Maja Skov

2015-01-01

Objective. General practitioners' (GPs') perception of risk is a cornerstone of preventive care. The aims of this interview study were to explore GPs' professional and personal attitudes and experiences regarding treatment with lipid-lowering drugs and their views on patient compliance. Methods....... The material was drawn from semistructured qualitative interviews. We sampled GPs purposively from ten selected practices, ensuring diversity of demographic, professional, and personal characteristics. The GPs were encouraged to describe examples from their own practices and reflect on them and were informed...... that the focus was their personal attitudes and experiences. Systematic text condensation was applied for analysis in order to uncover the concepts and themes. Results. The analysis revealed the following 3 main themes: (1) use of cardiovascular guidelines and risk assessment tools, (2) strategies for managing...

Applying GPS to enhance understanding of transport-related physical activity.

Science.gov (United States)

Duncan, Mitch J; Badland, Hannah M; Mummery, W Kerry

2009-09-01

The purpose of the paper is to review the utility of the global positioning system (GPS) in the study of health-related physical activity. The paper draws from existing literature to outline the current work performed using GPS to examine transport-related physical activity, with a focus on the relative utility of the approach when combined with geographic information system (GIS) and other data sources including accelerometers. The paper argues that GPS, especially when used in combination with GIS and accelerometery, offers great promise in objectively measuring and studying the relationship of numerous environmental attributes to human behaviour in terms of physical activity and transport-related activity. Limitations to the use of GPS for the purpose of monitoring health-related physical activity are presented, and recommendations for future avenues of research are discussed.

Detection of fecal contamination on beef meat surfaces using handheld fluorescence imaging device (HFID)

Science.gov (United States)

Current meat inspection in slaughter plants, for food safety and quality attributes including potential fecal contamination, is conducted through by visual examination human inspectors. A handheld fluorescence-based imaging device (HFID) was developed to be an assistive tool for human inspectors by ...

Deformation analysis of Aceh April 11th 2012 earthquake using GPS observation data

Science.gov (United States)

Maulida, Putra; Meilano, Irwan; Sarsito, Dina A.; Susilo

2015-04-01

This research tries to estimate the co-seismic deformation of intraplate earthquake occurred off northern Sumatra coast which is about 100-200 km southwest of Sumatrasubduction zone. The earthquake mechanism was strike-slip with magnitude 8.6 and triggering aftershock with magnitude 8.2 two hours later. We estimated the co-seismic deformation by using the GPS (Global Positioning System) continuous data along western Sumatra coast. The GPS observation derived from Sumatran GPS Array (SuGAr) and Geospatial Information Agency (BIG). For data processing we used GPS Analyze at Massachusetts Institute of Technology (GAMIT) software and Global Kalman Filter (GLOBK) to estimate the co-seismic deformation. From the GPS daily solution, the result shows that the earthquake caused displacement for the GPS stations in Sumatra. GPS stations in northern Sumatra showed the displacement to the northeast with the average displacement was 15 cm. The biggest displacement was found at station BSIM which is located at Simeuleu Island off north west Sumatra coast. GPS station in middle part of Sumatra, the displacement was northwest. The earthquake also caused subsidence for stations in northern Sumatra, but from the time series there was not sign of subsidence was found at middle part of Sumatra. In addition, the effect of the earthquake was worldwide and affected the other GPS Stations around Hindia oceanic.

Economic influences on GPs' decisions to provide out-of-hours care.

Science.gov (United States)

Geue, Claudia; Skåtun, Diane; Sutton, Matt

2009-01-01

Introduction of the new general medical services contract offered UK general practices the option to discontinue providing out-of-hours (OOH) care. This aimed to improve GP recruitment and retention by offering a better work-life balance, but put primary care organisations under pressure to ensure sustainable delivery of these services. Many organisations arranged this by re-purchasing provision from individual GPs. To analyse which factors influence an individual GP's decision to re-provide OOH care when their practice has opted out. Cross-sectional questionnaire survey. Rural and urban general practices in Scotland, UK. A postal survey was sent to all GPs working in Scotland in 2006, with analyses weighted for differential response rates. Analysis included logistic regression of individuals' decisions to re-provide OOH care based on personal characteristics, work and non-work time commitments, income from other sources, and contracting primary care organisation. Of the 1707 GPs in Scotland whose practice had opted out, 40.6% participated in OOH provision. Participation rates of GPs within primary care organisations varied from 16.7% to 74.7%. Males with young children were substantially more likely to participate than males without children (odds ratio [OR] 2.44, 95% confidence interval [CI] = 1.36 to 4.40). GPs with higher-earning spouses were less likely to participate. This effect was reinforced if GPs had spouses who were also GPs (OR 0.52, 95% CI = 0.37 to 0.74). GPs with training responsibilities (OR 1.36, 95% CI = 1.09 to 1.71) and other medical posts (OR 1.38, 95% CI = 1.09 to 1.75) were more likely to re-provide OOH services. The opportunity to opt out of OOH care has provided flexibility for GPs to raise additional income, although primary care organisations vary in the extent to which they offer these opportunities. Examining intrinsic motivation is an area for future study.

Seasonal and circadian biases in bird tracking with solar GPS-tags.

Directory of Open Access Journals (Sweden)

Rafa Silva

Full Text Available Global Positioning System (GPS tags are nowadays widely used in wildlife tracking. This geolocation technique can suffer from fix loss biases due to poor satellite GPS geometry, that result in tracking data gaps leading to wrong research conclusions. In addition, new solar-powered GPS tags deployed on birds can suffer from a new "battery drain bias" currently ignored in movement ecology analyses. We use a GPS tracking dataset of bearded vultures (Gypaetus barbatus, tracked for several years with solar GPS tags, to evaluate the causes and triggers of fix and data retrieval loss biases. We compare two models of solar GPS tags using different data retrieval systems (Argos vs GSM-GPRS, and programmed with different duty cycles. Neither of the models was able to accomplish the duty cycle programed initially. Fix and data retrieval loss rates were always greater than expected, and showed non-random gaps in GPS locations. Number of fixes per month of tracking was a bad criterion to identify tags with smaller biases. Fix-loss rates were four times higher due to battery drain than due to poor GPS satellite geometry. Both tag models were biased due to the uneven solar energy available for the recharge of the tag throughout the annual cycle, resulting in greater fix-loss rates in winter compared to summer. In addition, we suggest that the bias found along the diurnal cycle is linked to a complex three-factor interaction of bird flight behavior, topography and fix interval. More fixes were lost when vultures were perching compared to flying, in rugged versus flat topography. But long fix-intervals caused greater loss of fixes in dynamic (flying versus static situations (perching. To conclude, we emphasize the importance of evaluating fix-loss bias in current tracking projects, and deploying GPS tags that allow remote duty cycle updates so that the most appropriate fix and data retrieval intervals can be selected.

Evaluation of a focussed protocol for hand-held echocardiography and computer-assisted auscultation in detecting latent rheumatic heart disease in scholars.

Science.gov (United States)

Zühlke, Liesl J; Engel, Mark E; Nkepu, Simpiwe; Mayosi, Bongani M

2016-08-01

Introduction Echocardiography is the diagnostic test of choice for latent rheumatic heart disease. The utility of echocardiography for large-scale screening is limited by high cost, complex diagnostic protocols, and time to acquire multiple images. We evaluated the performance of a brief hand-held echocardiography protocol and computer-assisted auscultation in detecting latent rheumatic heart disease with or without pathological murmur. A total of 27 asymptomatic patients with latent rheumatic heart disease based on the World Heart Federation criteria and 66 healthy controls were examined by standard cardiac auscultation to detect pathological murmur. Hand-held echocardiography using a focussed protocol that utilises one view - that is, the parasternal long-axis view - and one measurement - that is, mitral regurgitant jet - and a computer-assisted auscultation utilising an automated decision tool were performed on all patients. The sensitivity and specificity of computer-assisted auscultation in latent rheumatic heart disease were 4% (95% CI 1.0-20.4%) and 93.7% (95% CI 84.5-98.3%), respectively. The sensitivity and specificity of the focussed hand-held echocardiography protocol for definite rheumatic heart disease were 92.3% (95% CI 63.9-99.8%) and 100%, respectively. The test reliability of hand-held echocardiography was 98.7% for definite and 94.7% for borderline disease, and the adjusted diagnostic odds ratios were 1041 and 263.9 for definite and borderline disease, respectively. Computer-assisted auscultation has extremely low sensitivity but high specificity for pathological murmur in latent rheumatic heart disease. Focussed hand-held echocardiography has fair sensitivity but high specificity and diagnostic utility for definite or borderline rheumatic heart disease in asymptomatic patients.

Indoor/Outdoor Seamless Positioning Using Lighting Tags and GPS Cellular Phones for Personal Navigation

Science.gov (United States)

Namie, Hiromune; Morishita, Hisashi

The authors focused on the development of an indoor positioning system which is easy to use, portable and available for everyone. This system is capable of providing the correct position anywhere indoors, including onboard ships, and was invented in order to evaluate the availability of GPS indoors. Although the performance of GPS is superior outdoors, there has been considerable research regarding indoor GPS involving sensitive GPS, pseudolites (GPS pseudo satellite), RFID (Radio Frequency IDentification) tags, and wireless LAN .However, the positioning rate and the precision are not high enough for general use, which is the reason why these technologies have not yet spread to personal navigation systems. In this regard, the authors attempted to implement an indoor positioning system using cellular phones with built-in GPS and infrared light data communication functionality, which are widely used in Japan. GPS is becoming increasingly popular, where GPGGS sentences of the NMEA outputted from the GPS receiver provide spatiotemporal information including latitude, longitude, altitude, and time or ECEF xyz coordinates. As GPS applications grow rapidly, spatiotemporal data becomes key to the ubiquitous outdoor and indoor seamless positioning services at least for the entire area of Japan, as well as to becoming familiar with satellite positioning systems (e.g. GPS). Furthermore, the authors are also working on the idea of using PDAs (Personal Digital Assistants), as cellular phones with built-in GPS and PDA functionality are also becoming increasingly popular.

A Demonstration of GPS Landslide Monitoring Using Online Positioning User Service (OPUS)

Science.gov (United States)

Wang, G.

2011-12-01

Global Positioning System (GPS) technologies have been frequently applied to landslide study, both as a complement, and as an alternative to conventional surveying methods. However, most applications of GPS for landslide monitoring have been limited to the academic community for research purposes. High-accuracy GPS has not been widely equipped in geotechnical companies and used by technicians. The main issue that limits the applications of GPS in the practice of high-accuracy landslide monitoring is the complexity of GPS data processing. This study demonstrated an approach using the Online Positioning User Service (OPUS) (http://www.ngs.noaa.gov/OPUS) provided by the National Geodetic Survey (NGS) of National Oceanic and Atmospheric Administration (NOAA) to process GPS data and conduct long-term landslide monitoring in the Puerto Rico and Virgin Islands Region. Continuous GPS data collected at a creeping landslide site during two years were used to evaluate different scenarios for landslide surveying: continuous or campaign, long duration or short duration, morning or afternoon (different weather conditions). OPUS uses Continuously Operating Reference Station (CORS) managed by NGS (http://www.ngs.noaa.giv/CORS/) as references and user data as a rover to solve a position. There are 19 CORS permanent GPS stations in the Puerto Rico and Virgin Islands region. The dense GPS network provides a precise and reliable reference frame for subcentimeter-accuracy landslide monitoring in this region. Our criterion for the accuracy was the root-mean-square (RMS) of OPUS solutions over a 2-year period with respect to true landslide displacement time series overt the same period. The true landslide displacements were derived from a single-baseline (130 m) GPS processing by using 24-hour continuous data. If continuous GPS surveying is performed in the field, then OPUS static processing can provide 0.6 cm horizontal and 1.1 cm vertical precision with few outliers. If repeated

[Comfort and discomfort: the role of emotions in GPs' prescription practices].

Science.gov (United States)

Henriksen, Kristin; Hansen, Ebba Holme

2005-12-05

The role of emotions in GPs' prescribing has been ignored. The present article describes 20 GPs' reflections about what precedes comfort and discomfort in prescribing situations. In-depth interviews were done with 20 GPs who contributed with examples on an open comfort-discomfort scale. Analysis of the data was inspired by grounded theory. The GPs experienced a broad spectrum of emotions when prescribing. In every prescribing situation, conditions could pull towards both comfort and discomfort. Comfort appeared when the indication was correct and the patient's condition was serious, when the patient experienced the problem as serious, when the situation was acute and the medicine effective, and when the GP experienced himself as competent. Medicines were placed between comfort and discomfort when prescribing was perceived as indifferent, unproblematic and easy, when the GP was concerned about inflicting a sick role on the patients, and when patients were not convinced about the appropriateness of the medication. Discomfort appeared when there was a great risk of dependence, when GPs experienced and gave in to pressure, when they had to convince patients, and when they prescribed addictive medicine regularly. The totality of conditions in the situation determined the emotional state in the prescribing situation. The GPs' emotions reflected how they evaluated the appropriateness of their prescribing. This should be taken advantage of in rational pharmacotherapy. Future interventions should address both the rationality of GPs and their emotions.

Hand-held tidal breathing nasal nitric oxide measurement--a promising targeted case-finding tool for the diagnosis of primary ciliary dyskinesia

DEFF Research Database (Denmark)

Marthin, June Kehlet; Nielsen, Kim Gjerum

2013-01-01

BACKGROUND: Nasal nitric oxide (nNO) measurement is an established first line test in the work-up for primary ciliary dyskinesia (PCD). Tidal breathing nNO (TB-nNO) measurements require minimal cooperation and are potentially useful even in young children. Hand-held NO devices are becoming...... increasingly widespread for asthma management. Therefore, we chose to assess whether hand-held TB-nNO measurements reliably discriminate between PCD, and Healthy Subjects (HS) and included Cystic Fibrosis (CF) patients as a disease control group known to have intermediate nNO levels. METHODS: In this cross...... sectional, single centre, single occasion, proof-of-concept study in children and adults with PCD and CF, and in HS we compared feasibility, success rates, discriminatory capacity, repeatability and agreement between a hand-held electrochemical device equipped with a nNO software application sampling...

Ethics support for GPs: what should it look like?

Science.gov (United States)

Clark-Grill, Monika

2016-03-01

INTRODUCTION Ethics support services for hospital clinicians have become increasingly common globally but not as yet in New Zealand. However, an initiative to change this is gathering momentum. Its slogan 'Clinical ethics is everyone's business' indicates that the aim is to encompass all of health care, not just the hospital sector. General Practitioners (GPs) deal with ethical issues on a daily basis. These issues are often quite different from ethical issues in hospitals. To make future ethics support relevant for primary care, local GPs were interviewed to find out how they might envisage ethics support services that could be useful to them. METHODS A focus group interview with six GPs and semi-structured individual interviews with three GPs were conducted. Questions included how they made decisions on ethical issues at present, what they perceived as obstacles to ethical reflection and decision-making, and what support might be helpful. FINDINGS Three areas of ethics support were considered potentially useful: Formal ethics education during GP training, access to an ethicist for assistance with analysing an ethical issue, and professional guidance with structured ethics conversations in peer groups. CONCLUSION The complex nature of general practice requires GPs to be well educated and supported for handling ethical issues. The findings from this study could serve as input to the development of ethics support services. KEYWORDS General practice; primary care; ethics; support; education.

On the issues of probability distribution of GPS carrier phase observations

Science.gov (United States)

Luo, X.; Mayer, M.; Heck, B.

2009-04-01

In common practice the observables related to Global Positioning System (GPS) are assumed to follow a Gauss-Laplace normal distribution. Actually, full knowledge of the observables' distribution is not required for parameter estimation by means of the least-squares algorithm based on the functional relation between observations and unknown parameters as well as the associated variance-covariance matrix. However, the probability distribution of GPS observations plays a key role in procedures for quality control (e.g. outlier and cycle slips detection, ambiguity resolution) and in reliability-related assessments of the estimation results. Under non-ideal observation conditions with respect to the factors impacting GPS data quality, for example multipath effects and atmospheric delays, the validity of the normal distribution postulate of GPS observations is in doubt. This paper presents a detailed analysis of the distribution properties of GPS carrier phase observations using double difference residuals. For this purpose 1-Hz observation data from the permanent SAPOS

Assessment of 3D hydrologic deformation using GRACE and GPS

Science.gov (United States)

Watson, C. S.; Tregoning, P.; Fleming, K.; Burgette, R. J.; Featherstone, W. E.; Awange, J.; Kuhn, M.; Ramillien, G.

2009-12-01

Hydrological processes cause variations in gravitational potential and surface deformations, both of which are detectable with ever increasing precision using space geodetic techniques. By comparing the elastic deformation computed from continental water load estimates derived from the Gravity Recovery and Climate Experiment (GRACE), with three-dimensional surface deformation derived from GPS observations, there is clear potential to better understand global to regional hydrological processes, in addition to acquiring further insight into the systematic error contributions affecting each space geodetic technique. In this study, we compare elastic deformation derived from water load estimates taken from the CNES, CSR, GFZ and JPL time variable GRACE fields. We compare these surface displacements with those derived at a global network of GPS sites that have been homogeneously reprocessed in the GAMIT/GLOBK suite. We extend our comparison to include a series of different GPS solutions, with each solution only subtly different based on the methodology used to down weight the height component in realizing site coordinates on the terrestrial reference frame. Each of the GPS solutions incorporate modeling of atmospheric loading and utilization of the VMF1 and a priori zenith hydrostatic delays derived via ray tracing through ECMWF meteorological fields. The agreement between GRACE and GPS derived deformations is not limited to the vertical component, with excellent agreement in the horizontal component across areas where large hydrologic signals occur over broad spatial scales (with correlation in horizontal components as high as 0.9). Agreement is also observed at smaller scales, including across Europe. These comparisons assist in understanding the magnitude of current error contributions within both space geodetic techniques. With the emergence of homogeneously reprocessed GPS time series spanning the GRACE mission, this technique offers one possible means of

Survey reveals public open to ban on hand-held cell phone use and texting.

Science.gov (United States)

2013-01-01

A study performed by the Bureau of Transportation Statistics (BTS) reveals that the public is open to a ban on hand-held cell phone use while driving. The study is based on data from 2009s Omnibus Household Survey (OHS), which is administered by B...

Development of GPS data remote retrieval system using wireless LAN

Directory of Open Access Journals (Sweden)

Koichiro Doi

2012-11-01

Full Text Available A remote retrieval system, using a wireless LAN, was developed to retrieve dual-frequency GPS data. The system consists of a ground observation unit (comprising a dual-frequency GPS logger and a data transmission unit and a data retrieval unit. In this system, we use the ZigBee communication protocol to transmit control commands (2.4 GHz, 250 Kbps and a wireless LAN communication to transmit GPS data (2.4 GHz, 54 Mbps. Data of every 30 seconds to transmit to the data retrieval unit are re-sampled from 1-second data at 00 UT each day. We conducted three data-transmission tests with the system: (1 a ground data retrieval test, (2 a data retrieval test from the atmosphere of a few hundred meters high using a small unmanned aircraft, and (3 actual GPS-data retrieval tests from a GPS buoy deployed on sea ice at Nisi-no-ura Cove, Syowa Station, Antarctica. In test (1, we successfully received all the data from the ground observation unit when situated at distances of less than 400 m from the data retrieval unit. In test (2, we obtained approximately 24.5 MB of data from the aircraft at heights of less than 250 m. In test (3, we obtained approximately 23.5 MB of data from the GPS buoy within 10 minutes. The proposed system has the advantage of enabling continuous measurements without aborting the measurement at the data retrievals.

Algorithms for a hand-held miniature x-ray fluorescence analytical instrument

International Nuclear Information System (INIS)

Elam, W.T.; Newman, D.; Ziemba, F.

1998-01-01

The purpose of this joint program was to provide technical assistance with the development of a Miniature X-ray Fluorescence (XRF) Analytical Instrument. This new XRF instrument is designed to overcome the weaknesses of spectrometers commercially available at the present time. Currently available XRF spectrometers (for a complete list see reference 1) convert spectral information to sample composition using the influence coefficients technique or the fundamental parameters method. They require either a standard sample with composition relatively close to the unknown or a detailed knowledge of the sample matrix. They also require a highly-trained operator and the results often depend on the capabilities of the operator. In addition, almost all existing field-portable, hand-held instruments use radioactive sources for excitation. Regulatory limits on such sources restrict them such that they can only provide relatively weak excitation. This limits all current hand-held XRF instruments to poor detection limits and/or long data collection times, in addition to the licensing requirements and disposal problems for radioactive sources. The new XRF instrument was developed jointly by Quantrad Sensor, Inc., the Naval Research Laboratory (NRL), and the Department of Energy (DOE). This report describes the analysis algorithms developed by NRL for the new instrument and the software which embodies them

Evaluating the performance of a low-cost GPS in precision agriculture applications

DEFF Research Database (Denmark)

Jensen, Kjeld; Larsen, Morten; Simonsen, Tom

2012-01-01

Field Robots are often equipped with a Real Time Kinematic (RTK) GPS to obtain precise positioning. In many precision agriculture applications, however, the robot operates in semi-structured environments like orchards and row crops, where local sensors such as computer vision and laser range...... scanners can produce accurate positioning relative to the crops. GPS is then primarily needed for robust inter-row navigation. This work evaluates a new low-cost GPS. Static tests were used to test the absolute accuracy. To test the GPS in a precision agriculture environment it was installed on a robot...

Effect of forest canopy on GPS-based movement data

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Nicholas J. DeCesare; John R. Squires; Jay A. Kolbe

2005-01-01

The advancing role of Global Positioning System (GPS) technology in ecology has made studies of animal movement possible for larger and more vagile species. A simple field test revealed that lengths of GPS-based movement data were strongly biased (Pof forest canopy. Global Positioning System error added an average of 27.5% additional...

Stochastic Analysis of Differential GPS Surveys for Earth Dam ...

African Journals Online (AJOL)

In GPS measurement, we try to model not just the deterministic part of the measurement but also try to account for their stochastic behavior using the measurement variance-covariance matrix. The variance-covariance matrices are computed as part of a least squares adjustment. In this study, the results of GPS survey by ...

Learning Motivation and Adaptive Video Caption Filtering for EFL Learners Using Handheld Devices

Science.gov (United States)

Hsu, Ching-Kun

2015-01-01

The aim of this study was to provide adaptive assistance to improve the listening comprehension of eleventh grade students. This study developed a video-based language learning system for handheld devices, using three levels of caption filtering adapted to student needs. Elementary level captioning excluded 220 English sight words (see Section 1…

The use of civilian-type GPS receivers by the military and their vulnerability to jamming

Directory of Open Access Journals (Sweden)

Ludwig Combrinck

2012-05-01

Full Text Available We considered the impact of external influences on a GPS receiver and how these influences affect the capabilities of civilian-type GPS receivers. A standard commercial radio frequency signal generator and passive GPS antenna were used to test the sensitivity of GPS to intentional jamming; the possible effects of the terrain on the propagation of the jamming signal were also tested. It was found that the high sensitivity of GPS receivers and the low strength level of GPS satellite signals combine to make GPS receivers very vulnerable to intentional jamming or unintentional radio frequency interference. Terrain undulation was used to shield GPS antennas from the direct line-of-sight of the jamming antenna and this indicated that terrain characteristics can be used to mitigate the effects of jamming. These results illuminate the vulnerability of civilian-type GPS receivers to the possibility and the ease of disablement and establish the foundation for future work.

Attitudes of GPs towards Older Adults Psychology Services in the Scottish Highlands.

Science.gov (United States)

Todman, Jonathan P F; Law, Jim; MacDougall, Andrew

2011-01-01

The mental health of older adults is of increasing concern in an aging population and GPs are frequently the gatekeepers to specialist mental health services. Psychotherapy, social interventions and bibliotherapy all have an evidence-base for treating depression and anxiety in the elderly, as does pharmacological treatment. However, the referral rate from GPs for an Older Adults Clinical Psychology service in the Scottish Highlands in the months prior to the study had been very low and the reasons for this were not clear. General practitioners may have felt that depression and anxiety are 'understandable' in older adults and are therefore unsuitable for treatment, or they may have felt that psycho-pharmacotherapy treatments are more effective than the psychotherapy treatment options. Alternatively, local issues associated with the remote location of many NHS Highland GP practices and patients may have prevented them referring. Therefore, the current study aimed to elicit the therapeutic preferences of Highland GPs, the perceived availability of these options and an estimate of the prevalence of older adults in the area suffering from mild or moderate mental health problems. Questionnaires including brief quantitative and qualitative questions were sent to all 284 GPs in the area with 119 (46%) were completed and returned. Responses from GPs suggested that many patients with depression or anxiety may not be referred. The GPs indicated that social therapeutic options are seen to be as effective as pharmacological options and more effective than other psychological and bibliotherapy options. However, GPs indicated that they were substantially more likely to prescribe pharmacological options than other forms of therapy. The GPs suggested that lower waiting times and a more localised service would increase the likelihood of a referral being made. The current study suggests that low awareness of psychological service provision among GPs may have resulted in fewer

Real-Time Vehicle Data Logging System Using GPS And GSM

OpenAIRE

Win Minn Thet; MyoMaung Maung; Hla Myo Tun

2015-01-01

Abstract This paper proposes and implements a low cost Vehicle Data Logging System using GPS and GSM. This system allows a user to trace the present and past positions recorded in SD card. This system also reads the current position of the vehicle using GPS the data is sent via GSM service from the GSM network. The vehicles position including the driving speed the UTC time and data are stored in the SD card for live and past tracking. All of that GPS data is sent to PIC 18F4520 by the Uni...

The Integration of GPS Navigator Device with Vehicles Tracking System for Rental Cars Firms

OpenAIRE

Omarah O. Alharaki; Fahad S. Alaieri; Akram M. Zeki

2010-01-01

The aim of this research is to integrate the GPS tracking system (tracking device and web-based application) with GPS navigator for rental cars, allowing the company to use various applications to monitor and manage the cars. This is enable the firms and customers to communicate with each other via the GPS navigator. The system should be developed by applying new features in GPS tracking application devices in vehicles. This paper also proposes new features that can be applied to the GPS Navi...

A comparison between different error modeling of MEMS applied to GPS/INS integrated systems.

Science.gov (United States)

Quinchia, Alex G; Falco, Gianluca; Falletti, Emanuela; Dovis, Fabio; Ferrer, Carles

2013-07-24

Advances in the development of micro-electromechanical systems (MEMS) have made possible the fabrication of cheap and small dimension accelerometers and gyroscopes, which are being used in many applications where the global positioning system (GPS) and the inertial navigation system (INS) integration is carried out, i.e., identifying track defects, terrestrial and pedestrian navigation, unmanned aerial vehicles (UAVs), stabilization of many platforms, etc. Although these MEMS sensors are low-cost, they present different errors, which degrade the accuracy of the navigation systems in a short period of time. Therefore, a suitable modeling of these errors is necessary in order to minimize them and, consequently, improve the system performance. In this work, the most used techniques currently to analyze the stochastic errors that affect these sensors are shown and compared: we examine in detail the autocorrelation, the Allan variance (AV) and the power spectral density (PSD) techniques. Subsequently, an analysis and modeling of the inertial sensors, which combines autoregressive (AR) filters and wavelet de-noising, is also achieved. Since a low-cost INS (MEMS grade) presents error sources with short-term (high-frequency) and long-term (low-frequency) components, we introduce a method that compensates for these error terms by doing a complete analysis of Allan variance, wavelet de-nosing and the selection of the level of decomposition for a suitable combination between these techniques. Eventually, in order to assess the stochastic models obtained with these techniques, the Extended Kalman Filter (EKF) of a loosely-coupled GPS/INS integration strategy is augmented with different states. Results show a comparison between the proposed method and the traditional sensor error models under GPS signal blockages using real data collected in urban roadways.

Hand-held spectrophotometer design for textile fabrics

Science.gov (United States)

Böcekçi, Veysel Gökhan; Yıldız, Kazım

2017-09-01

In this study, a hand-held spectrophotometer was designed by taking advantage of the developments in modern optoelectronic technology. Spectrophotometer devices are used to determine the color information from the optic properties of the materials. As an alternative to a desktop spectrophotometer device we have implemented, it is the first prototype, low cost and portable. The prototype model designed for the textile industry can detect the color tone of any fabric. The prototype model consists of optic sensor, processor, display floors. According to the color applied on the optic sensor, it produces special frequency information on its output at that color value. In Arduino type processor, the frequency information is evaluated by the program we have written and the color tone information between 0-255 ton is decided and displayed on the screen.

An investigation of airborne GPS/INS for high accuracy position and velocity determination

Energy Technology Data Exchange (ETDEWEB)

Sun, H.; Cannon, M.E. [Calgary Univ., AB (Canada). Dept. of Geomatics Engineering; Owen, T.E.; Meindl, M.A. [Sandia National Labs., Albuquerque, NM (United States)

1993-12-31

An airborne test using a differential GPS-INS system in a Twin Otter was conducted by Sandia National Laboratories to assess the feasibility of using the integrated system for cm-level position and cm/s velocity. The INS is a miniaturized ring-laser gyro IMU jointly developed by Sandia and Honeywell while the GPS system consists of the NovAtel GPSCard{trademark}. INS position, velocity and attitude data were computed using Sandia`s SANDAC flight computer system and logged at 4 Hz and GPS data was acquired at a 1 Hz rate. The mission was approximately 2.5 hours in duration and the aircraft reached separations of up to 19 km from the base station. The data was post-processed using a centralized Kalman filter approach in which the double differenced carrier phase measurements are used to update the INS data. The INS position is in turn used to detect and correct GPS carrier phase cycle slips and also to bridge GPS outages. Results are presented for the GPS-only case and also for integrated GPS/INS.

Variability in GPS sources

NARCIS (Netherlands)

Jauncey, DL; King, EA; Bignall, HE; Lovell, JEJ; Kedziora-Chudczer, L; Tzioumis, AK; Tingay, SJ; Macquart, JP; McCulloch, PM

2003-01-01

Flux density monitoring data at 2.3 and 8.4 GHz is presented for a sample of 33 southern hemisphere GPS sources, drawn from the 2.7 GHz Parkes survey. This monitoring data, together with VLBI monitoring data, shows that a small fraction of these sources, similar to10%, vary. Their variability falls

Rail inspection system based on iGPS

Science.gov (United States)

Fu, Xiaoyan; Wang, Mulan; Wen, Xiuping

2018-05-01

Track parameters include gauge, super elevation, cross level and so on, which could be calculated through the three-dimensional coordinates of the track. The rail inspection system based on iGPS (indoor/infrared GPS) was composed of base station, receiver, rail inspection frame, wireless communication unit, display and control unit and data processing unit. With the continuous movement of the inspection frame, the system could accurately inspect the coordinates of rail; realize the intelligent detection and precision measurement. According to principle of angle intersection measurement, the inspection model was structured, and detection process was given.

A statistical study of GPS loss of lock caused by ionospheric disturbances

Science.gov (United States)

Tsugawa, T.; Nishioka, M.; Otsuka, Y.; Saito, A.; Kato, H.; Kubota, M.; Nagatsuma, T.; Murata, K. T.

2010-12-01

Two-dimensional total electron content (TEC) maps have been derived from ground-based GPS receiver networks and applied to studies of various ionospheric disturbances since mid-1990s. For the purpose of monitoring and researching ionospheric disturbances which can degrade GNSS navigations and cause loss-of-lock on GNSS signals, National Institute of Information and Communications Technology (NICT), Japan has developed TEC maps over Japan using the dense GPS network, GEONET, which consists of more than 1,200 GPS receivers and is operated by Geophysical Survey Institute, Japan. Currently, we are providing two-dimensional maps of absolute TEC, detrended TEC with 60, 30, 15-minute window, rate of TEC change index (ROTI), and loss-of-lock (LOL) on GPS signal over Japan. These data and quick-look maps since 1997 are archived and available in the website of NICT (http://wdc.nict.go.jp/IONO/). Recently developed GPS receiver networks in North America and Europe make it possible to obtain regional TEC maps with higher spatial and temporal resolution than the global weighted mean TEC maps in the IONEX format provided by several institutes such as International GNSS Service (IGS) and another global TEC map provided by MIT Haystack observatory. Recently, we have also developed the regional TEC maps over North America and Europe. These data and quick-look maps are also available in the NICT website. In this presentation, we will show some severe ionospheric events such as high latitude storm-time plasma bubbles and storm enhanced density events observed over Japan using the GPS-TEC database. These events cause loss-of-lock of GPS signals and large GPS positioning errors. We also discuss about the statistical characteristics of LOL on the GPS signal caused by ionospheric disturbances.

Mobility assessment of a rural population in the Netherlands using GPS measurements.

Science.gov (United States)

Klous, Gijs; Smit, Lidwien A M; Borlée, Floor; Coutinho, Roel A; Kretzschmar, Mirjam E E; Heederik, Dick J J; Huss, Anke

2017-08-09

The home address is a common spatial proxy for exposure assessment in epidemiological studies but mobility may introduce exposure misclassification. Mobility can be assessed using self-reports or objectively measured using GPS logging but self-reports may not assess the same information as measured mobility. We aimed to assess mobility patterns of a rural population in the Netherlands using GPS measurements and self-reports and to compare GPS measured to self-reported data, and to evaluate correlates of differences in mobility patterns. In total 870 participants filled in a questionnaire regarding their transport modes and carried a GPS-logger for 7 consecutive days. Transport modes were assigned to GPS-tracks based on speed patterns. Correlates of measured mobility data were evaluated using multiple linear regression. We calculated walking, biking and motorised transport durations based on GPS and self-reported data and compared outcomes. We used Cohen's kappa analyses to compare categorised self-reported and GPS measured data for time spent outdoors. Self-reported time spent walking and biking was strongly overestimated when compared to GPS measurements. Participants estimated their time spent in motorised transport accurately. Several variables were associated with differences in mobility patterns, we found for instance that obese people (BMI > 30 kg/m 2 ) spent less time in non-motorised transport (GMR 0.69-0.74) and people with COPD tended to travel longer distances from home in motorised transport (GMR 1.42-1.51). If time spent walking outdoors and biking is relevant for the exposure to environmental factors, then relying on the home address as a proxy for exposure location may introduce misclassification. In addition, this misclassification is potentially differential, and specific groups of people will show stronger misclassification of exposure than others. Performing GPS measurements and identifying explanatory factors of mobility patterns may assist

GPS-based household interview survey for the Cincinnati, Ohio Region.

Science.gov (United States)

2012-02-01

Methods for Conducting a Large-Scale GPS-Only Survey of Households: Past Household Travel Surveys (HTS) in the United States have only piloted small subsamples of Global Positioning Systems (GPS) completes compared with 1-2 day self-reported travel i...

The future of GPS-based electric power system measurements, operation and control

Energy Technology Data Exchange (ETDEWEB)

Rizy, D.T. [Oak Ridge National Lab., TN (United States); Wilson, R.E. [Western Area Power Administration, Golden, CO (United States); Martin, K.E.; Litzenberger, W.H. [Bonneville Power Administration, Portland, OR (United States); Hauer, J.F. [Pacific Northwest National Lab., Richland, WA (United States); Overholt, P.N. [Dept. of Energy, Washington, DC (United States); Sobajic, D.J. [Electric Power Research Inst., Palo Alto, CA (United States)

1998-11-01

Much of modern society is powered by inexpensive and reliable electricity delivered by a complex and elaborate electric power network. Electrical utilities are currently using the Global Positioning System-NAVSTAR (GPS) timekeeping to improve the network`s reliability. Currently, GPS synchronizes the clocks on dynamic recorders and aids in post-mortem analysis of network disturbances. Two major projects have demonstrated the use of GPS-synchronized power system measurements. In 1992, the Electric Power Research Institute`s (EPRI) sponsored Phase Measurements Project used a commercially available Phasor Measurements Unit (PMU) to collect GPS-synchronized measurements for analyzing power system problems. In 1995, Bonneville Power Administration (BPA) and Western Area Power Administration (WAPA) under DOE`s and EPRI`s sponsorship launched the Wide Area Measurements (WAMS) project. WAMS demonstrated GPS-synchronized measurements over a large area of their power networks and demonstrated the networking of GPS-based measurement systems in BPA and WAPA. The phasor measurement technology has also been used to conduct dynamic power system tests. During these tests, a large dynamic resistor was inserted to simulate a small power system disturbance.

Implementasi Sistem Pelacakan Kendaraan Bermotor Menggunakan Gps Dan Gprs Dengan Integrasi Googlemap

Directory of Open Access Journals (Sweden)

Yazid Dul Muchlisin

2011-07-01

Full Text Available Abstract— Vehicle tracking system using GPS and GPRS integration googlemap provide information that is maximized with the technology of GPS (Global Positioning System receiver which can indicate the position of the vehicle with the map and the ability of the appointment of direction and position coordinates (x, y or latitude, longitude textually and visual at any location. Vehicle tracking system is built using equipment GIS (Geographic Information System and dedicated to smartphones which support Global Positioning System (GPS, as well as portable computers, using General Packet Radio Service (GPRS as a connection to the internet. The hardware used is a smartphone that supports GPS with supporting tools used are GoogleMaps, Notepad + +, NetBeans IDE 6.5.1, Mysql, Java (J2ME, PHP, JavaScript. The results of this system in the form of tracking system capable of monitoring the movement of vehicles on an ongoing position by utilizing GPS and GPRS as the sender of the wireless data and Internet connections.   Keywords— GIS, GPS, GPRS, googlemaps, J2ME,

A Java-based tool for creating KML files from GPS waypoints

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Kinnicutt, P. G.; Rivard, C.; Rimer, S.

2008-12-01

Google Earth provides a free tool with powerful capabilities for visualizing geoscience images and data. Commercial software tools exist for doing sophisticated digitizing and spatial modeling , but for the purposes of presentation, visualization and overlaying aerial images with data Google Earth provides much of the functionality. Likewise, with current technologies in GPS (Global Positioning System) systems and with Google Earth Plus, it is possible to upload GPS waypoints, tracks and routes directly into Google Earth for visualization. However, older technology GPS units and even low-cost GPS units found today may lack the necessary communications interface to a computer (e.g. no Bluetooth, no WiFi, no USB, no Serial, etc.) or may have an incompatible interface, such as a Serial port but no USB adapter available. In such cases, any waypoints, tracks and routes saved in the GPS unit or recorded in a field notebook must be manually transferred to a computer for use in a GIS system or other program. This presentation describes a Java-based tool developed by the author which enables users to enter GPS coordinates in a user-friendly manner, then save these coordinates in a Keyhole MarkUp Language (KML) file format, for visualization in Google Earth. This tool either accepts user-interactive input or accepts input from a CSV (Comma Separated Value) file, which can be generated from any spreadsheet program. This tool accepts input in the form of lat/long or UTM (Universal Transverse Mercator) coordinates. This presentation describes this system's applicability through several small case studies. This free and lightweight tool simplifies the task of manually inputting GPS data into Google Earth for people working in the field without an automated mechanism for uploading the data; for instance, the user may not have internet connectivity or may not have the proper hardware or software. Since it is a Java application and not a web- based tool, it can be installed on one

Exploring field-of-view non-uniformities produced by a hand-held spectroradiometer

Directory of Open Access Journals (Sweden)

Tamir Caras

2011-01-01

Full Text Available The shape of a spectroradiometer’s field of view (FOV affects the way spectral measurements are acquired. Knowing this property is a prerequisite for the correct use of the spectrometer. If the substrate is heterogeneous, the ability to accurately know what is being measured depends on knowing the FOV location, shape, spectral and spatial sensitivity. The GER1500 is a hand-held spectrometer with a fixed lens light entry slit and has a laser guide that allows control over the target by positioning the entire unit. In the current study, the FOV of the GER1500 was mapped and analysed. The spectral and spatial non-uniformities of the FOV were examined and were found to be spectrally independent. The relationship between the FOV and the built-in laser guide was tested and found to have a linear displacement dependent on the distance to the target. This allows an accurate prediction of the actual FOV position. A correction method to improve the agreement between the expected and measured reflectance over heterogeneous targets was developed and validated. The methods described are applicable and may be of use with other hand-held spectroradiometers.

GPS-derived crustal deformation in Azerbaijan

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Safarov, Rafig; Mammadov, Samir; Kadirov, Fakhraddin

2017-04-01

Crustal deformations of the Earth's crust in Azerbaijan were studied based on GPS measurements. The GPS velocity vectors for Azerbaijan, Iran, Georgia, and Armenia were used in order to estimate the deformation rates. It is found that compression is observable along the Greater Caucasus, in Gobustan, the Kura depression, Nakhchyvan Autonomous Republic, and adjacent areas of Iran. The axes of compression/contraction of the crust in the Greater Caucasus region are oriented in the S-NE direction. The maximum strain rate is observed in the zone of mud volcanism at the SHIK site (Shykhlar), which is marked by a sharp change in the direction of the compression axes (SW-NE). It is revealed that the deformation field also includes the zones where strain rates are very low. These zones include the Caspian-Guba and northern Gobustan areas, characterized by extensive development of mud volcanism. The extension zones are confined to the Lesser Caucasus and are revealed in the Gyadabei (GEDA) and Shusha (SHOU) areas. The analysis of GPS data for the territory of Azerbaijan and neighboring countries reveals the heterogeneous patterns of strain field in the region. This fact suggests that the block model is most adequate for describing the structure of the studied region. The increase in the number of GPS stations would promote increasing the degree of detail in the reconstructions of the deformation field and identifying the microplate boundaries.It is concluded that the predominant factor responsible for the eruption of mud volcanoes is the intensity of gasgeneration processes in the earth's interior, while deformation processes play the role of a trigger. The zone of the epicenters of strong earthquakes is correlated to the gradient zone in the crustal strain rates.

Absolute GPS Positioning Using Genetic Algorithms

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Ramillien, G.

A new inverse approach for restoring the absolute coordinates of a ground -based station from three or four observed GPS pseudo-ranges is proposed. This stochastic method is based on simulations of natural evolution named genetic algorithms (GA). These iterative procedures provide fairly good and robust estimates of the absolute positions in the Earth's geocentric reference system. For comparison/validation, GA results are compared to the ones obtained using the classical linearized least-square scheme for the determination of the XYZ location proposed by Bancroft (1985) which is strongly limited by the number of available observations (i.e. here, the number of input pseudo-ranges must be four). The r.m.s. accuracy of the non -linear cost function reached by this latter method is typically ~10-4 m2 corresponding to ~300-500-m accuracies for each geocentric coordinate. However, GA can provide more acceptable solutions (r.m.s. errors < 10-5 m2), even when only three instantaneous pseudo-ranges are used, such as a lost of lock during a GPS survey. Tuned GA parameters used in different simulations are N=1000 starting individuals, as well as Pc=60-70% and Pm=30-40% for the crossover probability and mutation rate, respectively. Statistical tests on the ability of GA to recover acceptable coordinates in presence of important levels of noise are made simulating nearly 3000 random samples of erroneous pseudo-ranges. Here, two main sources of measurement errors are considered in the inversion: (1) typical satellite-clock errors and/or 300-metre variance atmospheric delays, and (2) Geometrical Dilution of Precision (GDOP) due to the particular GPS satellite configuration at the time of acquisition. Extracting valuable information and even from low-quality starting range observations, GA offer an interesting alternative for high -precision GPS positioning.

What keeps Melbourne GPs satisfied in their jobs?

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Walker, Kate Anne; Pirotta, Marie

2007-10-01

Workforce shortages make it important to promote job satisfaction and career longevity in general practitioners. We aimed to investigate strategies that maintain and improve Melbourne (Victoria) GP job satisfaction. A postal survey of a random selection of The Royal Australian College of General Practitioners vocationally recognised GPs (N=860). Open ended answers were coded according to themes and compared between genders. Thirty-eight percent of surveyed GPs responded. The mean satisfaction score was 50 out of 70 (SD 9). Women GPs were more satisfied than men with life-work balance (pwork and intellectual stimulation. Strategies to improve GP satisfaction were increased pay, reduced paperwork, and improved administrative systems. General practitioners were satisfied with their jobs due to the intrinsic qualities of their work and workplace. Decreasing the administrative burden, increasing remuneration and improving practice supports may improve metropolitan GP job satisfaction.

GPS-based tracking system for TOPEX orbit determination

Science.gov (United States)

Melbourne, W. G.

1984-01-01

A tracking system concept is discussed that is based on the utilization of the constellation of Navstar satellites in the Global Positioning System (GPS). The concept involves simultaneous and continuous metric tracking of the signals from all visible Navstar satellites by approximately six globally distributed ground terminals and by the TOPEX spacecraft at 1300-km altitude. Error studies indicate that this system could be capable of obtaining decimeter position accuracies and, most importantly, around 5 cm in the radial component which is key to exploiting the full accuracy potential of the altimetric measurements for ocean topography. Topics covered include: background of the GPS, the precision mode for utilization of the system, past JPL research for using the GPS in precision applications, the present tracking system concept for high accuracy satellite positioning, and results from a proof-of-concept demonstration.

Implementation Of Code And Carrier Tracking Loops For Software GPS Receivers

Directory of Open Access Journals (Sweden)

Win Kay Khaing

2015-06-01

Full Text Available Abstract GPS is playing in very important role in our modern mobile societies. Software approach is very flexible rather than the traditional hardware receivers. The soft-GPS receiver includes two portions hardware and software. In hardware portion an antenna filter down-converter from RF Radio Frequency to IF Intermediate Frequency and an ADC Analog to Digital Converter are included. In software portion signal processing such as acquisition tracking and navigation that runs on general purpose processor is included. The GPS signal is taken from N-FUELS Full Educational Library of Signals for Navigation signal simulator. The heart of soft-GPS receiver is the synchronization processes such as acquisition and tracking. In tracking there are two main loops for code and carrier tracking. The objective of this paper is to analyse and find the optimum discriminator function for the code tracking loop in soft-GPS receivers. The delay lock loop DLL is a well-known technique to track the codes for GNSS spread spectrum systems. This paper also presents non-coherent square law DLLs and the impacts of some parameters on DLL discriminators such as number of samples per chip early-late spacing different C No values where C denotes the signal power and No is the noise spectral density and the impact of with or without front-end device. The results of discriminator outputs are illustrated by using S-curves. Testing results with the real GPS signal are also described. This optimized discriminator functions can be implemented in any soft-GPS receivers.

75 FR 43206 - In the Matter of Certain Wireless Communications System Server Software, Wireless Handheld...

Science.gov (United States)

2010-07-23

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-706] In the Matter of Certain Wireless Communications System Server Software, Wireless Handheld Devices and Battery Packs: Notice of Commission... United States after importation of certain wireless communications system server software, wireless...

Applying Hand-Held 3D Printing Technology to the Teaching of VSEPR Theory

Science.gov (United States)

Dean, Natalie L.; Ewan, Corrina; McIndoe, J. Scott

2016-01-01

The use of hand-held 3D printing technology provides a unique and engaging approach to learning VSEPR theory by enabling students to draw three-dimensional depictions of different molecular geometries, giving them an appreciation of the shapes of the building blocks of complex molecular structures. Students are provided with 3D printing pens and…

Retained satellite information influences performance of GPS devices in a forested ecosystem

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