Roadmap on optical sensors.

PubMed

Ferreira, Mário F S; Castro-Camus, Enrique; Ottaway, David J; López-Higuera, José Miguel; Feng, Xian; Jin, Wei; Jeong, Yoonchan; Picqué, Nathalie; Tong, Limin; Reinhard, Björn M; Pellegrino, Paul M; Méndez, Alexis; Diem, Max; Vollmer, Frank; Quan, Qimin

2017-08-01

Sensors are devices or systems able to detect, measure and convert magnitudes from any domain to an electrical one. Using light as a probe for optical sensing is one of the most efficient approaches for this purpose. The history of optical sensing using some methods based on absorbance, emissive and florescence properties date back to the 16th century. The field of optical sensors evolved during the following centuries, but it did not achieve maturity until the demonstration of the first laser in 1960. The unique properties of laser light become particularly important in the case of laser-based sensors, whose operation is entirely based upon the direct detection of laser light itself, without relying on any additional mediating device. However, compared with freely propagating light beams, artificially engineered optical fields are in increasing demand for probing samples with very small sizes and/or weak light-matter interaction. Optical fiber sensors constitute a subarea of optical sensors in which fiber technologies are employed. Different types of specialty and photonic crystal fibers provide improved performance and novel sensing concepts. Actually, structurization with wavelength or subwavelength feature size appears as the most efficient way to enhance sensor sensitivity and its detection limit. This leads to the area of micro- and nano-engineered optical sensors. It is expected that the combination of better fabrication techniques and new physical effects may open new and fascinating opportunities in this area. This roadmap on optical sensors addresses different technologies and application areas of the field. Fourteen contributions authored by experts from both industry and academia provide insights into the current state-of-the-art and the challenges faced by researchers currently. Two sections of this paper provide an overview of laser-based and frequency comb-based sensors. Three sections address the area of optical fiber sensors, encompassing both conventional, specialty and photonic crystal fibers. Several other sections are dedicated to micro- and nano-engineered sensors, including whispering-gallery mode and plasmonic sensors. The uses of optical sensors in chemical, biological and biomedical areas are described in other sections. Different approaches required to satisfy applications at visible, infrared and THz spectral regions are also discussed. Advances in science and technology required to meet challenges faced in each of these areas are addressed, together with suggestions on how the field could evolve in the near future.

Roadmap on optical sensors

NASA Astrophysics Data System (ADS)

Ferreira, Mário F. S.; Castro-Camus, Enrique; Ottaway, David J.; López-Higuera, José Miguel; Feng, Xian; Jin, Wei; Jeong, Yoonchan; Picqué, Nathalie; Tong, Limin; Reinhard, Björn M.; Pellegrino, Paul M.; Méndez, Alexis; Diem, Max; Vollmer, Frank; Quan, Qimin

2017-08-01

Sensors are devices or systems able to detect, measure and convert magnitudes from any domain to an electrical one. Using light as a probe for optical sensing is one of the most efficient approaches for this purpose. The history of optical sensing using some methods based on absorbance, emissive and florescence properties date back to the 16th century. The field of optical sensors evolved during the following centuries, but it did not achieve maturity until the demonstration of the first laser in 1960. The unique properties of laser light become particularly important in the case of laser-based sensors, whose operation is entirely based upon the direct detection of laser light itself, without relying on any additional mediating device. However, compared with freely propagating light beams, artificially engineered optical fields are in increasing demand for probing samples with very small sizes and/or weak light-matter interaction. Optical fiber sensors constitute a subarea of optical sensors in which fiber technologies are employed. Different types of specialty and photonic crystal fibers provide improved performance and novel sensing concepts. Actually, structurization with wavelength or subwavelength feature size appears as the most efficient way to enhance sensor sensitivity and its detection limit. This leads to the area of micro- and nano-engineered optical sensors. It is expected that the combination of better fabrication techniques and new physical effects may open new and fascinating opportunities in this area. This roadmap on optical sensors addresses different technologies and application areas of the field. Fourteen contributions authored by experts from both industry and academia provide insights into the current state-of-the-art and the challenges faced by researchers currently. Two sections of this paper provide an overview of laser-based and frequency comb-based sensors. Three sections address the area of optical fiber sensors, encompassing both conventional, specialty and photonic crystal fibers. Several other sections are dedicated to micro- and nano-engineered sensors, including whispering-gallery mode and plasmonic sensors. The uses of optical sensors in chemical, biological and biomedical areas are described in other sections. Different approaches required to satisfy applications at visible, infrared and THz spectral regions are also discussed. Advances in science and technology required to meet challenges faced in each of these areas are addressed, together with suggestions on how the field could evolve in the near future.

Evaluation of a Sensor System for Detecting Humans Trapped under Rubble: A Pilot Study

PubMed Central

Kasai, Ritaro; Cosentino, Sarah; Giacomo, Cimarelli; Mochida, Yasuaki; Yamada, Hiroya; Guarnieri, Michele; Takanishi, Atsuo

2018-01-01

Rapid localization of injured survivors by rescue teams to prevent death is a major issue. In this paper, a sensor system for human rescue including three different types of sensors, a CO2 sensor, a thermal camera, and a microphone, is proposed. The performance of this system in detecting living victims under the rubble has been tested in a high-fidelity simulated disaster area. Results show that the CO2 sensor is useful to effectively reduce the possible concerned area, while the thermal camera can confirm the correct position of the victim. Moreover, it is believed that the use of microphones in connection with other sensors would be of great benefit for the detection of casualties. In this work, an algorithm to recognize voices or suspected human noise under rubble has also been developed and tested. PMID:29534055

An Improved High-Sensitivity Airborne Transient Electromagnetic Sensor for Deep Penetration

PubMed Central

Chen, Shudong; Guo, Shuxu; Wang, Haofeng; He, Miao; Liu, Xiaoyan; Qiu, Yu; Zhang, Shuang; Yuan, Zhiwen; Zhang, Haiyang; Fang, Dong; Zhu, Jun

2017-01-01

The investigation depth of transient electromagnetic sensors can be effectively increased by reducing the system noise, which is mainly composed of sensor internal noise, electromagnetic interference (EMI), and environmental noise, etc. A high-sensitivity airborne transient electromagnetic (AEM) sensor with low sensor internal noise and good shielding effectiveness is of great importance for deep penetration. In this article, the design and optimization of such an AEM sensor is described in detail. To reduce sensor internal noise, a noise model with both a damping resistor and a preamplifier is established and analyzed. The results indicate that a sensor with a large diameter, low resonant frequency, and low sampling rate will have lower sensor internal noise. To improve the electromagnetic compatibility of the sensor, an electromagnetic shielding model for a central-tapped coil is established and discussed in detail. Previous studies have shown that unclosed shields with multiple layers and center grounding can effectively suppress EMI and eddy currents. According to these studies, an improved differential AEM sensor is constructed with a diameter, resultant effective area, resonant frequency, and normalized equivalent input noise of 1.1 m, 114 m2, 35.6 kHz, and 13.3 nV/m2, respectively. The accuracy of the noise model and the shielding effectiveness of the sensor have been verified experimentally. The results show a good agreement between calculated and measured results for the sensor internal noise. Additionally, over 20 dB shielding effectiveness is achieved in a complex electromagnetic environment. All of these results show a great improvement in sensor internal noise and shielding effectiveness. PMID:28106718

Positioning of the sensor cell on the sensing area using cell trapping pattern in incubation type planar patch clamp biosensor.

PubMed

Wang, Zhi-Hong; Takada, Noriko; Uno, Hidetaka; Ishizuka, Toru; Yawo, Hiromu; Urisu, Tsuneo

2012-08-01

Positioning the sensor cell on the micropore of the sensor chip and keeping it there during incubation are problematic tasks for incubation type planar patch clamp biosensors. To solve these problems, we formed on the Si sensor chip's surface a cell trapping pattern consisting of a lattice pattern with a round area 5 μm deep and with the micropore at the center of the round area. The surface of the sensor chip was coated with extra cellular matrix collagen IV, and HEK293 cells on which a chimera molecule of channel-rhodopsin-wide-receiver (ChR-WR) was expressed, were then seeded. We examined the effects of this cell trapping pattern on the biosensor's operation. In the case of a flat sensor chip without a cell trapping pattern, it took several days before the sensor cell covered the micropore and formed an almost confluent state. As a result, multi-cell layers easily formed and made channel current measurements impossible. On the other hand, the sensor chip with cell trapping pattern easily trapped cells in the round area, and formed the colony consisted of the cell monolayer covering the micropore. A laser (473 nm wavelength) induced channel current was observed from the whole cell arrangement formed using the nystatin perforation technique. The observed channel current characteristics matched measurements made by using a pipette patch clamp. Copyright © 2012 Elsevier B.V. All rights reserved.

A Two-Phase Coverage-Enhancing Algorithm for Hybrid Wireless Sensor Networks.

PubMed

Zhang, Qingguo; Fok, Mable P

2017-01-09

Providing field coverage is a key task in many sensor network applications. In certain scenarios, the sensor field may have coverage holes due to random initial deployment of sensors; thus, the desired level of coverage cannot be achieved. A hybrid wireless sensor network is a cost-effective solution to this problem, which is achieved by repositioning a portion of the mobile sensors in the network to meet the network coverage requirement. This paper investigates how to redeploy mobile sensor nodes to improve network coverage in hybrid wireless sensor networks. We propose a two-phase coverage-enhancing algorithm for hybrid wireless sensor networks. In phase one, we use a differential evolution algorithm to compute the candidate's target positions in the mobile sensor nodes that could potentially improve coverage. In the second phase, we use an optimization scheme on the candidate's target positions calculated from phase one to reduce the accumulated potential moving distance of mobile sensors, such that the exact mobile sensor nodes that need to be moved as well as their final target positions can be determined. Experimental results show that the proposed algorithm provided significant improvement in terms of area coverage rate, average moving distance, area coverage-distance rate and the number of moved mobile sensors, when compare with other approaches.

A Two-Phase Coverage-Enhancing Algorithm for Hybrid Wireless Sensor Networks

PubMed Central

Zhang, Qingguo; Fok, Mable P.

2017-01-01

Providing field coverage is a key task in many sensor network applications. In certain scenarios, the sensor field may have coverage holes due to random initial deployment of sensors; thus, the desired level of coverage cannot be achieved. A hybrid wireless sensor network is a cost-effective solution to this problem, which is achieved by repositioning a portion of the mobile sensors in the network to meet the network coverage requirement. This paper investigates how to redeploy mobile sensor nodes to improve network coverage in hybrid wireless sensor networks. We propose a two-phase coverage-enhancing algorithm for hybrid wireless sensor networks. In phase one, we use a differential evolution algorithm to compute the candidate’s target positions in the mobile sensor nodes that could potentially improve coverage. In the second phase, we use an optimization scheme on the candidate’s target positions calculated from phase one to reduce the accumulated potential moving distance of mobile sensors, such that the exact mobile sensor nodes that need to be moved as well as their final target positions can be determined. Experimental results show that the proposed algorithm provided significant improvement in terms of area coverage rate, average moving distance, area coverage–distance rate and the number of moved mobile sensors, when compare with other approaches. PMID:28075365

Development of an Open Source Based Sensor Platform for an Advanced and Comprehensive in-situ DOC Monitoring

NASA Astrophysics Data System (ADS)

Schima, Robert; Goblirsch, Tobias; Paschen, Mathias; Rinke, Karsten; Schelwat, Heinz; Dietrich, Peter; Bumberger, Jan

2016-04-01

The impact of global change, intensive agriculture and complex interactions between humans and the environment show different effects on different scales. However, the desire to obtain a better understanding of ecosystems and process dynamics in nature accentuates the need for observing these processes in higher temporal and spatial resolutions. Especially with regard to the process dynamics and heterogeneity of water catchment areas, a comprehensive monitoring of the ongoing processes and effects remains to be a challenging issue in the field of applied environmental research. Moreover, harsh conditions and a variety of influencing process parameters are representing a particular challenge due to an adaptive in-situ monitoring of vast areas. Today, open source based electronics and cost-effective sensors and sensor components are offering a promising approach to investigate new possibilities of smart phone based mobile data acquisition and comprehensive ad-hoc monitoring of environmental processes. Accordingly, our project aims the development of new strategies for mobile data acquisition and real-time processing of user-specific environmental data, based on a holistic and integrated process. To this end, the concept of our monitoring system covers the data collection, data processing and data integration as well as the data provision within one infrastructure. The whole monitoring system consists of several mobile sensor devices, a smart phone app (Android) and a web service for data processing, data provision and data visualization. The smart phone app allows the configuration of the mobile sensor device and provides some built-in functions such as data visualization or data transmission via e-mail. Besides the measurement of temperature and humidity in air, the mobile sensor device is able to acquire sensor readings for the content of dissolved organic compounds (λ = 254 nm) and turbidity (λ = 860 nm) of surface water based on the developed optical in-situ sensor probe. Here, the miniaturized optical sensor probe allows the monitoring of even shallow water bodies with a depth of less than 5 cm. Compared to common techniques, the inexpensive sensor parts and robust emitting LEDs allow an improved widespread and comprehensive monitoring due to a higher amount of sensor devices. Furthermore, the system consists of a GPS module, a real-time clock and a GSM unit which allow space and time resolved measurements. On October 6th, 2015 an initial experiment was started at the Bode catchment in the Harz region (Germany). Here, the developed DOC and turbidity sensor probes were installed directly at the riverside next to existing sampling points of a large-scaled long-term observation project. The results show a good correspondence between our sensor development and the installed and established instruments. This represents a decisive and cost-effective contribution in the area of environmental research and the monitoring of vast catchment areas.

Intense transient electric field sensor based on the electro-optic effect of LiNbO{sub 3}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Qing, E-mail: yangqing@cqu.edu.cn; Sun, Shangpeng; Han, Rui

2015-10-15

Intense transient electric field measurements are widely applied in various research areas. An optical intense E-field sensor for time-domain measurements, based on the electro-optic effect of lithium niobate, has been studied in detail. Principles and key issues in the design of the sensor are presented. The sensor is insulated, small in size (65 mm × 15 mm × 15 mm), and suitable for high-intensity (<801 kV/m) electric field measurements over a wide frequency band (10 Hz–10 MHz). The input/output characteristics of the sensor were obtained and the sensor calibrated. Finally, an application using this sensor in testing laboratory lightning impulsesmore » and in measuring transient electric fields during switch-on of a disconnector confirmed that the sensor is expected to find widespread use in transient intense electric field measurement applications.« less

Intense transient electric field sensor based on the electro-optic effect of LiNbO3

NASA Astrophysics Data System (ADS)

Yang, Qing; Sun, Shangpeng; Han, Rui; Sima, Wenxia; Liu, Tong

2015-10-01

Intense transient electric field measurements are widely applied in various research areas. An optical intense E-field sensor for time-domain measurements, based on the electro-optic effect of lithium niobate, has been studied in detail. Principles and key issues in the design of the sensor are presented. The sensor is insulated, small in size (65 mm × 15 mm × 15 mm), and suitable for high-intensity (<801 kV/m) electric field measurements over a wide frequency band (10 Hz-10 MHz). The input/output characteristics of the sensor were obtained and the sensor calibrated. Finally, an application using this sensor in testing laboratory lightning impulses and in measuring transient electric fields during switch-on of a disconnector confirmed that the sensor is expected to find widespread use in transient intense electric field measurement applications.

Development of a Cost-Effective Airborne Remote Sensing System for Coastal Monitoring

PubMed Central

Kim, Duk-jin; Jung, Jungkyo; Kang, Ki-mook; Kim, Seung Hee; Xu, Zhen; Hensley, Scott; Swan, Aaron; Duersch, Michael

2015-01-01

Coastal lands and nearshore marine areas are productive and rapidly changing places. However, these areas face many environmental challenges related to climate change and human-induced impacts. Space-borne remote sensing systems may be restricted in monitoring these areas because of their spatial and temporal resolutions. In situ measurements are also constrained from accessing the area and obtaining wide-coverage data. In these respects, airborne remote sensing sensors could be the most appropriate tools for monitoring these coastal areas. In this study, a cost-effective airborne remote sensing system with synthetic aperture radar and thermal infrared sensors was implemented to survey coastal areas. Calibration techniques and geophysical model algorithms were developed for the airborne system to observe the topography of intertidal flats, coastal sea surface current, sea surface temperature, and submarine groundwater discharge. PMID:26437413

Development of a Cost-Effective Airborne Remote Sensing System for Coastal Monitoring.

PubMed

Kim, Duk-jin; Jung, Jungkyo; Kang, Ki-mook; Kim, Seung Hee; Xu, Zhen; Hensley, Scott; Swan, Aaron; Duersch, Michael

2015-09-30

Coastal lands and nearshore marine areas are productive and rapidly changing places. However, these areas face many environmental challenges related to climate change and human-induced impacts. Space-borne remote sensing systems may be restricted in monitoring these areas because of their spatial and temporal resolutions. In situ measurements are also constrained from accessing the area and obtaining wide-coverage data. In these respects, airborne remote sensing sensors could be the most appropriate tools for monitoring these coastal areas. In this study, a cost-effective airborne remote sensing system with synthetic aperture radar and thermal infrared sensors was implemented to survey coastal areas. Calibration techniques and geophysical model algorithms were developed for the airborne system to observe the topography of intertidal flats, coastal sea surface current, sea surface temperature, and submarine groundwater discharge.

Urban heat island impacts on plant phenology: intra-urban variability and response to land cover

NASA Astrophysics Data System (ADS)

Zipper, Samuel C.; Schatz, Jason; Singh, Aditya; Kucharik, Christopher J.; Townsend, Philip A.; Loheide, Steven P., II

2016-05-01

Despite documented intra-urban heterogeneity in the urban heat island (UHI) effect, little is known about spatial or temporal variability in plant response to the UHI. Using an automated temperature sensor network in conjunction with Landsat-derived remotely sensed estimates of start/end of the growing season, we investigate the impacts of the UHI on plant phenology in the city of Madison WI (USA) for the 2012-2014 growing seasons. Median urban growing season length (GSL) estimated from temperature sensors is ˜5 d longer than surrounding rural areas, and UHI impacts on GSL are relatively consistent from year-to-year. Parks within urban areas experience a subdued expression of GSL lengthening resulting from interactions between the UHI and a park cool island effect. Across all growing seasons, impervious cover in the area surrounding each temperature sensor explains >50% of observed variability in phenology. Comparisons between long-term estimates of annual mean phenological timing, derived from remote sensing, and temperature-based estimates of individual growing seasons show no relationship at the individual sensor level. The magnitude of disagreement between temperature-based and remotely sensed phenology is a function of impervious and grass cover surrounding the sensor, suggesting that realized GSL is controlled by both local land cover and micrometeorological conditions.

Effect of embedded printed circuit board (PCB) sensors on the mechanical behavior of glass fiber-reinforced polymer (GFRP) structures

NASA Astrophysics Data System (ADS)

Javdanitehran, M.; Hoffmann, R.; Groh, J.; Vossiek, M.; Ziegmann, G.

2016-06-01

The embedding of dielectric chipless sensors for cure monitoring into fiber-reinforced thermosets allows for monitoring and controlling the curing process and consequently higher quality in production. The embedded sensors remain after the processing in the structure. This affects the integrity of the composite structure locally. In order to investigate these effects on the mechanical behavior of the glass fiber-reinforced polymer (GFRP), sensors made on special low loss substrates are integrated into laminates with different lay-ups and thicknesses using vacuum assisted resin transfer molding (VARTM) method. In a parametric study the size of the sensor is varied to observe its influence on the strength and the stiffness of the laminates according to its lay-up and thickness. The size and orientation of the resin rich areas near sensors as well as the distortion in load bearing area as the consequences of the introduction of the sensors are investigated in conjunction with the strength of the structure. An empirical model is proposed by the authors which involves the previously mentioned factors and is used as a rapid tool for the prediction of the changes in bending and tensile strength of simple structures with embedded sensors. The methodology for model’s calibration as well as the validation of the model against the experimental data of different laminates with distinct lay-ups and thicknesses are presented in this work. Mechanical tests under tensile and bending loading indicate that the reduction of the structure’s strength due to sensor integration can be attributed to the size and the orientation of rich resin zones and depends over and above on the size of distorted load bearing area. Depending on the sensor’s elastic modulus the stiffness of the structure may vary through the introduction of a sensor.

Combining environment and health information systems for the assessment of atmospheric pollution on human health.

PubMed

Skouloudis, Andreas N; Kassomenos, Pavlos

2014-08-01

The use of emerging technologies for environmental monitoring with satellite and in-situ sensors have become essential instruments for assessing the impact of environmental pollution on human health, especially in areas that require high spatial and temporal resolution. This was until recently a rather difficult problem. Regrettably, with classical approaches the spatial resolution is frequently inadequate in reporting environmental causes and health effects in the same time scale. This work examines with new tools different levels of air-quality with sensor monitoring with the aim to associate those with severe health effects. The process established here facilitates the precise representation of human exposure with the population attributed in a fine spatial grid and taking into account environmental stressors of human exposure. These stressors can be monitored with innovative sensor units with a temporal resolution that accurately describes chronic and acute environmental burdens. The current understanding of the situation in densely populated areas can be properly analyzed, before commitments are made for reductions in total emissions as well as for assessing the effects of reduced trans-boundary fluxes. In addition, the data processed here with in-situ sensors can assist in establishing more effective regulatory policies for the protection of vulnerable population groups and the satellite monitoring instruments permit abatement strategies that are close to real-time over large geographical areas. Copyright © 2014 Elsevier B.V. All rights reserved.

High-efficient Unmanned Aircraft System Operations for Ecosystem Assessment

NASA Astrophysics Data System (ADS)

Xu, H.; Zhang, H.

2016-02-01

Diverse national and international agencies support the idea that incorporating Unmanned Aircraft Systems (UAS) into ecosystem assessment will improve the operations efficiency and accuracy. In this paper, a UAS will be designed to monitor the Gulf of Mexico's coastal area ecosystems intelligently and routinely. UAS onboard sensors will capture information that can be utilized to detect and geo-locate areas affected by invasive grasses. Moreover, practical ecosystem will be better assessed by analyzing the collected information. Compared with human-based/satellite-based surveillance, the proposed strategy is more efficient and accurate, and eliminates limitations and risks associated with human factors. State of the art UAS onboard sensors (e.g. high-resolution electro optical camera, night vision camera, thermal sensor etc.) will be used for monitoring coastal ecosystems. Once detected the potential risk in ecosystem, the onboard GPS data will be used to geo-locate and to store the exact coordinates of the affected area. Moreover, the UAS sensors will be used to observe and to record the daily evolution of coastal ecosystems. Further, benefitting from the data collected by the UAS, an intelligent big data processing scheme will be created to assess the ecosystem evolution effectively. Meanwhile, a cost-efficient intelligent autonomous navigation strategy will be implemented into the UAS, in order to guarantee that the UAS can fly over designated areas, and collect significant data in a safe and effective way. Furthermore, the proposed UAS-based ecosystem surveillance and assessment methodologies can be utilized for natural resources conservation. Flying UAS with multiple state of the art sensors will monitor and report the actual state of high importance natural resources frequently. Using the collected data, the ecosystem conservation strategy can be performed effectively and intelligently.

Infrasound Sensor and Porous-Hose Filter Characterization Results

NASA Astrophysics Data System (ADS)

Hart, D. M.; Harris, J. M.

2008-12-01

The Ground-Based Nuclear Explosion Monitoring Research and Development (GNEM R&D) program at Sandia National Laboratories (SNL) is regarded as the primary center for unbiased expertise in testing and evaluation of geophysical sensors and instrumentation for nuclear explosion monitoring. Over the past year much of our work has focused in the area of infrasound sensor characterization through the continuing development of an infrasound sensor characterization test-bed. Our main areas of focus have been in new sensor characterization and understanding the effects of porous-hose filters for reducing acoustic background signals. Three infrasound sensors were evaluated for characteristics of instrument response, linearity and self-noise. The sensors tested were Chaparral Physics model 2.5 low-gain, New Mexico Tech All-Sensor and the Inter-Mountain Labs model SS avalanche sensor. For the infrasound sensors tested, the test results allow us to conclude that two of the three sensors had sufficiently quiet noise floor to be at or below the Acoustic low-noise model from 0.1 to 7 Hz, which make those sensors suitable to explosion monitoring. The other area of focus has been to understand the characteristics of porous-hose filters used at some monitoring sites. For this, an experiment was designed in which two infrasound sensors were co- located. One sensor was connected to a typical porous-hose spatial filter consisting of eight individual hoses covering a 30m aperture and the second sensor was left open to unimpeded acoustic input. Data were collected for several days, power spectrum computed for two-hour windows and the relative gain of the porous-hose filters were estimated by dividing the power spectrum. The porous-hose filter appears to attenuate less than 3 dB (rel 1 Pa**2/Hz) below 0.1 Hz and as much as 25 dB at 1 Hz and between 20 to 10 dB above 10 Hz. Several more experiments will be designed to address the effects of different characteristics of the individual porous-hoses, such as length, number and geometric arrangement. This work directly impacts the Ground-Based Nuclear Explosion Monitoring mission by providing a facility, equipment, and personnel to give the operational monitoring agencies confidence in deployed instrumentation and capability for mission success.

Precisely Controlled Ultrathin Conjugated Polymer Films for Large Area Transparent Transistors and Highly Sensitive Chemical Sensors.

PubMed

Khim, Dongyoon; Ryu, Gi-Seong; Park, Won-Tae; Kim, Hyunchul; Lee, Myungwon; Noh, Yong-Young

2016-04-13

A uniform ultrathin polymer film is deposited over a large area with molecularlevel precision by the simple wire-wound bar-coating method. The bar-coated ultrathin films not only exhibit high transparency of up to 90% in the visible wavelength range but also high charge carrier mobility with a high degree of percolation through the uniformly covered polymer nanofibrils. They are capable of realizing highly sensitive multigas sensors and represent the first successful report of ethylene detection using a sensor based on organic field-effect transistors. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Smart Sensor Demonstration Payload

NASA Technical Reports Server (NTRS)

Schmalzel, John; Bracey, Andrew; Rawls, Stephen; Morris, Jon; Turowski, Mark; Franzl, Richard; Figueroa, Fernando

2010-01-01

Sensors are a critical element to any monitoring, control, and evaluation processes such as those needed to support ground based testing for rocket engine test. Sensor applications involve tens to thousands of sensors; their reliable performance is critical to achieving overall system goals. Many figures of merit are used to describe and evaluate sensor characteristics; for example, sensitivity and linearity. In addition, sensor selection must satisfy many trade-offs among system engineering (SE) requirements to best integrate sensors into complex systems [1]. These SE trades include the familiar constraints of power, signal conditioning, cabling, reliability, and mass, and now include considerations such as spectrum allocation and interference for wireless sensors. Our group at NASA s John C. Stennis Space Center (SSC) works in the broad area of integrated systems health management (ISHM). Core ISHM technologies include smart and intelligent sensors, anomaly detection, root cause analysis, prognosis, and interfaces to operators and other system elements [2]. Sensor technologies are the base fabric that feed data and health information to higher layers. Cost-effective operation of the complement of test stands benefits from technologies and methodologies that contribute to reductions in labor costs, improvements in efficiency, reductions in turn-around times, improved reliability, and other measures. ISHM is an active area of development at SSC because it offers the potential to achieve many of those operational goals [3-5].

Digitally Programmable Analogue Circuits for Sensor Conditioning Systems

PubMed Central

Zatorre, Guillermo; Medrano, Nicolás; Sanz, María Teresa; Aldea, Concepción; Calvo, Belén; Celma, Santiago

2009-01-01

This work presents two current-mode integrated circuits designed for sensor signal preprocessing in embedded systems. The proposed circuits have been designed to provide good signal transfer and fulfill their function, while minimizing the load effects due to building complex conditioning architectures. The processing architecture based on the proposed building blocks can be reconfigured through digital programmability. Thus, sensor useful range can be expanded, changes in the sensor operation can be compensated for and furthermore, undesirable effects such as device mismatching and undesired physical magnitudes sensor sensibilities are reduced. The circuits were integrated using a 0.35 μm standard CMOS process. Experimental measurements, load effects and a study of two different tuning strategies are presented. From these results, system performance is tested in an application which entails extending the linear range of a magneto-resistive sensor. Circuit area, average power consumption and programmability features allow these circuits to be included in embedded sensing systems as a part of the analogue conditioning components. PMID:22412331

Effects of satellite image spatial aggregation and resolution on estimates of forest land area

Treesearch

M.D. Nelson; R.E. McRoberts; G.R. Holden; M.E. Bauer

2009-01-01

Satellite imagery is being used increasingly in association with national forest inventories (NFIs) to produce maps and enhance estimates of forest attributes. We simulated several image spatial resolutions within sparsely and heavily forested study areas to assess resolution effects on estimates of forest land area, independent of other sensor characteristics. We...

Wireless Sensor Networks - Node Localization for Various Industry Problems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Derr, Kurt; Manic, Milos

Fast, effective monitoring following airborne releases of toxic substances is critical to mitigate risks to threatened population areas. Wireless sensor nodes at fixed predetermined locations may monitor such airborne releases and provide early warnings to the public. A challenging algorithmic problem is determining the locations to place these sensor nodes while meeting several criteria: 1) provide complete coverage of the domain, and 2) create a topology with problem dependent node densities, while 3) minimizing the number of sensor nodes. This manuscript presents a novel approach to determining optimal sensor placement, Advancing Front mEsh generation with Constrained dElaunay Triangulation and Smoothingmore » (AFECETS) that addresses these criteria. A unique aspect of AFECETS is the ability to determine wireless sensor node locations for areas of high interest (hospitals, schools, high population density areas) that require higher density of nodes for monitoring environmental conditions, a feature that is difficult to find in other research work. The AFECETS algorithm was tested on several arbitrary shaped domains. AFECETS simulation results show that the algorithm 1) provides significant reduction in the number of nodes, in some cases over 40%, compared to an advancing front mesh generation algorithm, 2) maintains and improves optimal spacing between nodes, and 3) produces simulation run times suitable for real-time applications.« less

Wireless Sensor Networks - Node Localization for Various Industry Problems

DOE PAGES

Derr, Kurt; Manic, Milos

2015-06-01

Fast, effective monitoring following airborne releases of toxic substances is critical to mitigate risks to threatened population areas. Wireless sensor nodes at fixed predetermined locations may monitor such airborne releases and provide early warnings to the public. A challenging algorithmic problem is determining the locations to place these sensor nodes while meeting several criteria: 1) provide complete coverage of the domain, and 2) create a topology with problem dependent node densities, while 3) minimizing the number of sensor nodes. This manuscript presents a novel approach to determining optimal sensor placement, Advancing Front mEsh generation with Constrained dElaunay Triangulation and Smoothingmore » (AFECETS) that addresses these criteria. A unique aspect of AFECETS is the ability to determine wireless sensor node locations for areas of high interest (hospitals, schools, high population density areas) that require higher density of nodes for monitoring environmental conditions, a feature that is difficult to find in other research work. The AFECETS algorithm was tested on several arbitrary shaped domains. AFECETS simulation results show that the algorithm 1) provides significant reduction in the number of nodes, in some cases over 40%, compared to an advancing front mesh generation algorithm, 2) maintains and improves optimal spacing between nodes, and 3) produces simulation run times suitable for real-time applications.« less

Nanoporous Pirani sensor based on anodic aluminum oxide

NASA Astrophysics Data System (ADS)

Jeon, Gwang-Jae; Kim, Woo Young; Shim, Hyun Bin; Lee, Hee Chul

2016-09-01

A nanoporous Pirani sensor based on anodic aluminum oxide (AAO) is proposed, and the quantitative relationship between the performance of the sensor and the porosity of the AAO membrane is characterized with a theoretical model. The proposed Pirani sensor is composed of a metallic resistor on a suspended nanoporous membrane, which simultaneously serves as the sensing area and the supporting structure. The AAO membrane has numerous vertically-tufted nanopores, resulting in a lower measurable pressure limit due to both the increased effective sensing area and the decreased effective thermal loss through the supporting structure. Additionally, the suspended AAO membrane structure, with its outer periphery anchored to the substrate, known as a closed-type design, is demonstrated using nanopores of AAO as an etch hole without a bulk micromachining process used on the substrate. In a CMOS-compatible process, a 200 μm × 200 μm nanoporous Pirani sensor with porosity of 25% was capable of measuring the pressure from 0.1 mTorr to 760 Torr. With adjustment of the porosity of the AAO, the measurable range could be extended toward lower pressures of more than one decade compared to a non-porous membrane with an identical footprint.

X-ray computed microtomography characterizes the wound effect that causes sap flow underestimation by thermal dissipation sensors.

PubMed

Marañón-Jiménez, S; Van den Bulcke, J; Piayda, A; Van Acker, J; Cuntz, M; Rebmann, C; Steppe, K

2018-02-01

Insertion of thermal dissipation (TD) sap flow sensors in living tree stems causes damage of the wood tissue, as is the case with other invasive methods. The subsequent wound formation is one of the main causes of underestimation of tree water-use measured by TD sensors. However, the specific alterations in wood anatomy in response to inserted sensors have not yet been characterized, and the linked dysfunctions in xylem conductance and sensor accuracy are still unknown. In this study, we investigate the anatomical mechanisms prompting sap flow underestimation and the dynamic process of wound formation. Successive sets of TD sensors were installed in the early, mid and end stage of the growing season in diffuse- and ring-porous trees, Fagus sylvatica (Linnaeus) and Quercus petraea ((Mattuschka) Lieblein), respectively. The trees were cut in autumn and additional sensors were installed in the cut stem segments as controls without wound formation. The wounded area and volume surrounding each sensor was then visually determined by X-ray computed microtomography (X-ray microCT). This technique allowed the characterization of vessel anatomical transformations such as tyloses formation, their spatial distribution and quantification of reduction in conductive area. MicroCT scans showed considerable formation of tyloses that reduced the conductive area of vessels surrounding the inserted TD probes, thus causing an underestimation in sap flux density (SFD) in both beech and oak. Discolored wood tissue was ellipsoidal, larger in the radial plane, more extensive in beech than in oak, and also for sensors installed for longer times. However, the severity of anatomical transformations did not always follow this pattern. Increased wound size with time, for example, did not result in larger SFD underestimation. This information helps us to better understand the mechanisms involved in wound effects with TD sensors and allows the provision of practical recommendations to reduce biases associated with wounding in field sap flow measurements. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Flush mounting of thin film sensors

NASA Technical Reports Server (NTRS)

Moore, Thomas C., Sr. (Inventor)

1992-01-01

Flush mounting of a sensor on a surface is provided by first forming a recessed area on the surface. Next, an adhesive bonding mixture is introduced into the recessed area. The adhesive bonding mixture is chosen to provide thermal expansion matching with the surface surrounding the recessed area. A strip of high performance polymeric tape is provided, with the sensor attached to the underside thereof, and the tape is positioned over the recessed area so that it acts as a carrier of the sensor. A shim having flexibility so that it will conform to the surface surrounding the recessed area is placed over the tape, and a vacuum pad is placed over the shim. The area above the surface is then evacuated while holding the sensor flush with the surface during curing of the adhesive bonding mixture. After such curing, the pad, shim, and tape are removed from the sensor, electrical connections for the sensor are provided, after which the remaining space in the recessed area is filled with a polymeric foam.

Microsensor research

NASA Astrophysics Data System (ADS)

Hughes, R. C.; Drebing, C. G.

1990-04-01

The technology that led to very large scale integrated circuits on silicon chips also provides a basis for new microsensors that are small, inexpensive, low power, rugged, and reliable. Two examples of microsensors Sandia is developing that take advantage of this technology are the microelectronic chemical sensor array and the radiation sensing field effect transistor (RADFET). Increasingly, the technology of chemical sensing needs new microsensor concepts. Applications in this area include environmental monitoring, criminal investigations, and state-of-health monitoring, both for equipment and living things. Chemical microsensors can satisfy sensing needs in the industrial, consumer, aerospace, and defense sectors. The microelectronic chemical-sensor array may address some of these applications. We have fabricated six separate chemical gas sensing areas on the microelectronic chemical sensor array. By using different catalytic metals on the gate areas of the diodes, we can selectively sense several gases.

The Disturbing Effect of the Stray Magnetic Fields on Magnetoimpedance Sensors

PubMed Central

Wang, Tao; Zhou, Yong; Lei, Chong; Zhi, Shaotao; Guo, Lei; Li, Hengyu; Wu, Zhizheng; Xie, Shaorong; Luo, Jun; Pu, Huayan

2016-01-01

The disturbing effect of the stray magnetic fields of Fe-based amorphous ribbons on the giant magnetoimpedance (GMI) sensor has been investigated systematically in this paper. Two simple methods were used for examining the disturbing effect of the stray magnetic fields of ribbons on the GMI sensor. In order to study the influence of the stray magnetic fields on the GMI effect, the square-shaped amorphous ribbons were tested in front, at the back, on the left and on the top of a meander-line GMI sensor made up of soft ferromagnetic films, respectively. Experimental results show that the presence of ribbons in front or at the back of GMI sensor shifts the GMI curve to a lower external magnetic field. On the contrary, the presence of ribbons on the left or on the top of the GMI sensor shifts the GMI curve to a higher external magnetic field, which is related to the coupling effect of the external magnetic field and the stray magnetic fields. The influence of the area and angle of ribbons on GMI was also studied in this work. The GMI sensor exhibits high linearity for detection of the stray magnetic fields, which has made it feasible to construct a sensitive magnetometer for detecting the typical stray magnetic fields of general soft ferromagnetic materials. PMID:27763498

Particle sensor array

NASA Technical Reports Server (NTRS)

Buehler, Martin G. (Inventor); Blaes, Brent R. (Inventor); Lieneweg, Udo (Inventor)

1994-01-01

A particle sensor array which in a preferred embodiment comprises a static random access memory having a plurality of ion-sensitive memory cells, each such cell comprising at least one pull-down field effect transistor having a sensitive drain surface area (such as by bloating) and at least one pull-up field effect transistor having a source connected to an offset voltage. The sensitive drain surface area and the offset voltage are selected for memory cell upset by incident ions such as alpha-particles. The static random access memory of the present invention provides a means for selectively biasing the memory cells into the same state in which each of the sensitive drain surface areas is reverse biased and then selectively reducing the reversed bias on these sensitive drain surface areas for increasing the upset sensitivity of the cells to ions. The resulting selectively sensitive memory cells can be used in a number of applications. By way of example, the present invention can be used for measuring the linear energy transfer of ion particles, as well as a device for assessing the resistance of CMOS latches to Cosmic Ray induced single event upsets. The sensor of the present invention can also be used to determine the uniformity of an ion beam.

Enzyme-free monitoring of glucose utilization in stimulated macrophages using carbon nanotube-decorated electrochemical sensor

NASA Astrophysics Data System (ADS)

Madhurantakam, Sasya; Karnam, Jayanth Babu; Rayappan, John Bosco Balaguru; Krishnan, Uma Maheswari

2017-11-01

Carbon nanotubes (CNTs) have been extensively explored for a diverse range of applications due to their unique electrical and mechanical properties. CNT-incorporated electrochemical sensors have exhibited enhanced sensitivity towards the analyte molecule due to the excellent electron transfer properties of CNTs. In addition, CNTs possess a large surface area-to-volume ratio that favours the adhesion of analyte molecules as well as enhances the electroactive area. Most of the electrochemical sensors have employed CNTs as a nano-interface to promote electron transfer and as an immobilization matrix for enzymes. The present work explores the potential of CNTs to serve as a catalytic interface for the enzymeless quantification of glucose. The figure of merits for the enzymeless sensor was comparable to the performance of several enzyme-based sensors reported in literature. The developed sensor was successfully employed to determine the glucose utilization of unstimulated and stimulated macrophages. The significant difference in the glucose utilization levels in activated macrophages and quiescent cells observed in the present investigation opens up the possibilities of new avenues for effective medical diagnosis of inflammatory disorders.

Remotely operable sample-taking appliance, especially for ascertaining radioactivity profiles in contaminated material surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanulik, J.

1983-09-20

A sample-taking appliance comprises several sensors arranged on a turntable like sensor carrier in such a manner that the application areas of the small sensor sponges decrease stepwise from the first to the last sensor. By simple rotation of the turntable the sensors can be brought successively into a working position. The sensor carrier is preferably accommodated in a housing which is open at the bottom and which is raisable and lowerable in the frame of the appliance by, for example, a threaded spindle. The threaded spindle is driven by an electric motor. For each sampling the sensor carrier ismore » lowered until the cell voltage corresponds to a predetermined desired value. This produces sufficiently precise and reproductible measured values of the electrolytic current for ascertaining the removed layer thickness. The appliance makes it possible to take material samples even from locations of high radiation loading. The material layers removed as samples lie concentrically above each other so that the graduation of the application areas comes into full effect and the material samples taken by the small sponges and the radioactivity contained therein are not falsified.« less

The effect of Co-doping on the humidity sensing properties of ordered mesoporous TiO2

NASA Astrophysics Data System (ADS)

Li, Zhong; Haidry, Azhar Ali; Gao, Bin; Wang, Tao; Yao, ZhengJun

2017-08-01

Monitoring of humidity is of utmost importance as it is essential part of almost every process in our life. Many commercial humidity sensors based on metal oxide semiconductors are available in the market, but there is still need to synthesize low-cost, fast and highly sensitive humidity sensors with no interference from background environment. The aim of this work was to fabricate the ordered mesoporous un-doped and Co-doped TiO2 (0.1-5 mol% Co) and to analyze its humidity sensing properties at room temperatures. The ordered mesoporous powders with high specific surface area (SSA) were prepared by multicomponent self-assembly procedure and then spray-coated onto the sensor substrates with interdigitated gold electrodes. The sensors exhibited excellent stability and reproducible resistance change under various relative humidity percentages (9-90% RH) with negligible effect of background environment. For instance, the response to 90% RH at room temperature was about five orders of magnitude (∼1.39 × 105) and the response time (Tres) was ∼24 s. The reaction/recovery times of the sensors were compared with commercial humidity sensor to show that the reaction times in this work are not given by the surface reaction of water vapor on the sensor surfaces, rather these are mainly influenced by the experimental setup. The sensor response increased up to 3 mol% Co-contents and then decreased for 5 mol% Co-contents. Based on the experimental results, the surface reaction of humidity is discussed related to specific surface area, average grain size and cobalt contents to understand the humidity sensing mechanism.

Ammonia sensing using arrays of silicon nanowires and graphene

NASA Astrophysics Data System (ADS)

Fobelets, K.; Panteli, C.; Sydoruk, O.; Li, Chuanbo

2018-06-01

Ammonia (NH3) is a toxic gas released in different industrial, agricultural and natural processes. It is also a biomarker for some diseases. These require NH3 sensors for health and safety reasons. To boost the sensitivity of solid-state sensors, the effective sensing area should be increased. Two methods are explored and compared using an evaporating pool of 0.5 mL NH4OH (28% NH3). In the first method an array of Si nanowires (Si NWA) is obtained via metal-assisted-electrochemical etching to increase the effective surface area. In the second method CVD graphene is suspended on top of the Si nanowires to act as a sensing layer. Both the effective surface area as well as the density of surface traps influences the amplitude of the response. The effective surface area of Si NWAs is 100 × larger than that of suspended graphene for the same top surface area, leading to a larger response in amplitude by a factor of ~7 notwithstanding a higher trap density in suspended graphene. The use of Si NWAs increases the response rate for both Si NWAs as well as the suspended graphene due to more effective NH3 diffusion processes.

Optimization of Emissions Sensor Networks Incorporating Tradeoffs Between Different Sensor Technologies

NASA Astrophysics Data System (ADS)

Nicholson, B.; Klise, K. A.; Laird, C. D.; Ravikumar, A. P.; Brandt, A. R.

2017-12-01

In order to comply with current and future methane emissions regulations, natural gas producers must develop emissions monitoring strategies for their facilities. In addition, regulators must develop air monitoring strategies over wide areas incorporating multiple facilities. However, in both of these cases, only a limited number of sensors can be deployed. With a wide variety of sensors to choose from in terms of cost, precision, accuracy, spatial coverage, location, orientation, and sampling frequency, it is difficult to design robust monitoring strategies for different scenarios while systematically considering the tradeoffs between different sensor technologies. In addition, the geography, weather, and other site specific conditions can have a large impact on the performance of a sensor network. In this work, we demonstrate methods for calculating optimal sensor networks. Our approach can incorporate tradeoffs between vastly different sensor technologies, optimize over typical wind conditions for a particular area, and consider different objectives such as time to detection or geographic coverage. We do this by pre-computing site specific scenarios and using them as input to a mixed-integer, stochastic programming problem that solves for a sensor network that maximizes the effectiveness of the detection program. Our methods and approach have been incorporated within an open source Python package called Chama with the goal of providing facility operators and regulators with tools for designing more effective and efficient monitoring systems. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energys National Nuclear Security Administration under contract DE-NA0003525.

Analyzing the Effects of UAV Mobility Patterns on Data Collection in Wireless Sensor Networks.

PubMed

Rashed, Sarmad; Soyturk, Mujdat

2017-02-20

Sensor nodes in a Wireless Sensor Network (WSN) can be dispersed over a remote sensing area (e.g., the regions that are hardly accessed by human beings). In such kinds of networks, datacollectionbecomesoneofthemajorissues. Getting connected to each sensor node and retrieving the information in time introduces new challenges. Mobile sink usage-especially Unmanned Aerial Vehicles (UAVs)-is the most convenient approach to covering the area and accessing each sensor node in such a large-scale WSN. However, the operation of the UAV depends on some parameters, such as endurance time, altitude, speed, radio type in use, and the path. In this paper, we explore various UAV mobility patterns that follow different paths to sweep the operation area in order to seek the best area coverage with the maximum number of covered nodes in the least amount of time needed by the mobile sink. We also introduce a new metric to formulate the tradeoff between maximizing the covered nodes and minimizing the operation time when choosing the appropriate mobility pattern. A realistic simulation environment is used in order to compare and evaluate the performance of the system. We present the performance results for the explored UAV mobility patterns. The results are very useful to present the tradeoff between maximizing the covered nodes and minimizing the operation time to choose the appropriate mobility pattern.

Analyzing the Effects of UAV Mobility Patterns on Data Collection in Wireless Sensor Networks

PubMed Central

Rashed, Sarmad; Soyturk, Mujdat

2017-01-01

Sensor nodes in a Wireless Sensor Network (WSN) can be dispersed over a remote sensing area (e.g., the regions that are hardly accessed by human beings). In such kinds of networks, data collection becomes one of the major issues. Getting connected to each sensor node and retrieving the information in time introduces new challenges. Mobile sink usage—especially Unmanned Aerial Vehicles (UAVs)—is the most convenient approach to covering the area and accessing each sensor node in such a large-scale WSN. However, the operation of the UAV depends on some parameters, such as endurance time, altitude, speed, radio type in use, and the path. In this paper, we explore various UAV mobility patterns that follow different paths to sweep the operation area in order to seek the best area coverage with the maximum number of covered nodes in the least amount of time needed by the mobile sink. We also introduce a new metric to formulate the tradeoff between maximizing the covered nodes and minimizing the operation time when choosing the appropriate mobility pattern. A realistic simulation environment is used in order to compare and evaluate the performance of the system. We present the performance results for the explored UAV mobility patterns. The results are very useful to present the tradeoff between maximizing the covered nodes and minimizing the operation time to choose the appropriate mobility pattern. PMID:28230727

A linearization time-domain CMOS smart temperature sensor using a curvature compensation oscillator.

PubMed

Chen, Chun-Chi; Chen, Hao-Wen

2013-08-28

This paper presents an area-efficient time-domain CMOS smart temperature sensor using a curvature compensation oscillator for linearity enhancement with a -40 to 120 °C temperature range operability. The inverter-based smart temperature sensors can substantially reduce the cost and circuit complexity of integrated temperature sensors. However, a large curvature exists on the temperature-to-time transfer curve of the inverter-based delay line and results in poor linearity of the sensor output. For cost reduction and error improvement, a temperature-to-pulse generator composed of a ring oscillator and a time amplifier was used to generate a thermal sensing pulse with a sufficient width proportional to the absolute temperature (PTAT). Then, a simple but effective on-chip curvature compensation oscillator is proposed to simultaneously count and compensate the PTAT pulse with curvature for linearization. With such a simple structure, the proposed sensor possesses an extremely small area of 0.07 mm2 in a TSMC 0.35-mm CMOS 2P4M digital process. By using an oscillator-based scheme design, the proposed sensor achieves a fine resolution of 0.045 °C without significantly increasing the circuit area. With the curvature compensation, the inaccuracy of -1.2 to 0.2 °C is achieved in an operation range of -40 to 120 °C after two-point calibration for 14 packaged chips. The power consumption is measured as 23 mW at a sample rate of 10 samples/s.

Intercomparison of cosmic-ray neutron sensors and water balance monitoring in an urban environment

NASA Astrophysics Data System (ADS)

Schrön, Martin; Zacharias, Steffen; Womack, Gary; Köhli, Markus; Desilets, Darin; Oswald, Sascha E.; Bumberger, Jan; Mollenhauer, Hannes; Kögler, Simon; Remmler, Paul; Kasner, Mandy; Denk, Astrid; Dietrich, Peter

2018-03-01

Sensor-to-sensor variability is a source of error common to all geoscientific instruments that needs to be assessed before comparative and applied research can be performed with multiple sensors. Consistency among sensor systems is especially critical when subtle features of the surrounding terrain are to be identified. Cosmic-ray neutron sensors (CRNSs) are a recent technology used to monitor hectometre-scale environmental water storages, for which a rigorous comparison study of numerous co-located sensors has not yet been performed. In this work, nine stationary CRNS probes of type CRS1000 were installed in relative proximity on a grass patch surrounded by trees, buildings, and sealed areas. While the dynamics of the neutron count rates were found to be similar, offsets of a few percent from the absolute average neutron count rates were found. Technical adjustments of the individual detection parameters brought all instruments into good agreement. Furthermore, we found a critical integration time of 6 h above which all sensors showed consistent dynamics in the data and their RMSE fell below 1 % of gravimetric water content. The residual differences between the nine signals indicated local effects of the complex urban terrain on the scale of several metres. Mobile CRNS measurements and spatial simulations with the URANOS neutron transport code in the surrounding area (25 ha) have revealed substantial sub-footprint heterogeneity to which CRNS detectors are sensitive despite their large averaging volume. The sealed and constantly dry structures in the footprint furthermore damped the dynamics of the CRNS-derived soil moisture. We developed strategies to correct for the sealed-area effect based on theoretical insights about the spatial sensitivity of the sensor. This procedure not only led to reliable soil moisture estimation during dry-out periods, it further revealed a strong signal of intercepted water that emerged over the sealed surfaces during rain events. The presented arrangement offered a unique opportunity to demonstrate the CRNS performance in complex terrain, and the results indicated great potential for further applications in urban climate research.

Smart Elasto-Magneto-Electric (EME) Sensors for Stress Monitoring of Steel Cables: Design Theory and Experimental Validation

PubMed Central

Zhang, Ru; Duan, Yuanfeng; Or, Siu Wing; Zhao, Yang

2014-01-01

An elasto-magnetic (EM) and magneto-electric (ME) effect based elasto-magneto-electric (EME) sensor has been proposed recently by the authors for stress monitoring of steel cables with obvious superiorities over traditional elasto-magnetic sensors. For design optimization and engineering application of the EME sensor, the design theory is interpreted with a developed model taking into account the EM coupling effect and ME coupling effect. This model is able to approximate the magnetization changes that a steel structural component undergoes when subjected to excitation magnetic field and external stress, and to simulate the induced ME voltages of the ME sensing unit located in the magnetization area. A full-scale experiment is then carried out to verify the model and to calibrate the EME sensor as a non-destructive evaluation (NDE) tool to monitor the cable stress. The experimental results agree well with the simulation results using the developed model. The proposed EME sensor proves to be feasible for stress monitoring of steel cables with high sensitivity, fast response, and ease of installation. PMID:25072348

Smart elasto-magneto-electric (EME) sensors for stress monitoring of steel cables: design theory and experimental validation.

PubMed

Zhang, Ru; Duan, Yuanfeng; Or, Siu Wing; Zhao, Yang

2014-07-28

An elasto-magnetic (EM) and magneto-electric (ME) effect based elasto-magneto-electric (EME) sensor has been proposed recently by the authors for stress monitoring of steel cables with obvious superiorities over traditional elasto-magnetic sensors. For design optimization and engineering application of the EME sensor, the design theory is interpreted with a developed model taking into account the EM coupling effect and ME coupling effect. This model is able to approximate the magnetization changes that a steel structural component undergoes when subjected to excitation magnetic field and external stress, and to simulate the induced ME voltages of the ME sensing unit located in the magnetization area. A full-scale experiment is then carried out to verify the model and to calibrate the EME sensor as a non-destructive evaluation (NDE) tool to monitor the cable stress. The experimental results agree well with the simulation results using the developed model. The proposed EME sensor proves to be feasible for stress monitoring of steel cables with high sensitivity, fast response, and ease of installation.

A calculation and uncertainty evaluation method for the effective area of a piston rod used in quasi-static pressure calibration

NASA Astrophysics Data System (ADS)

Gu, Tingwei; Kong, Deren; Shang, Fei; Chen, Jing

2018-04-01

This paper describes the merits and demerits of different sensors for measuring propellant gas pressure, the applicable range of the frequently used dynamic pressure calibration methods, and the working principle of absolute quasi-static pressure calibration based on the drop-weight device. The main factors affecting the accuracy of pressure calibration are analyzed from two aspects of the force sensor and the piston area. To calculate the effective area of the piston rod and evaluate the uncertainty between the force sensor and the corresponding peak pressure in the absolute quasi-static pressure calibration process, a method for solving these problems based on the least squares principle is proposed. According to the relevant quasi-static pressure calibration experimental data, the least squares fitting model between the peak force and the peak pressure, and the effective area of the piston rod and its measurement uncertainty, are obtained. The fitting model is tested by an additional group of experiments, and the peak pressure obtained by the existing high-precision comparison calibration method is taken as the reference value. The test results show that the peak pressure obtained by the least squares fitting model is closer to the reference value than the one directly calculated by the cross-sectional area of the piston rod. When the peak pressure is higher than 150 MPa, the percentage difference is less than 0.71%, which can meet the requirements of practical application.

Lightning Current Measurement with Fiber-Optic Sensor

NASA Technical Reports Server (NTRS)

Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.; Mata, Carlos T.; Mata, Angel G.; Snyder, Gary P.

2014-01-01

A fiber-optic current sensor is successfully developed with many potential applications for electric current measurement. Originally developed for in-flight lightning measurement, the sensor utilizes Faraday Effect in an optical fiber. The Faraday Effect causes linear light polarization in a fiber to rotate when the fiber is exposed to a magnetic field. The polarization change is detected using a reflective polarimetric scheme. Forming fiber loops and applying Ampere's law, measuring the total light rotation results in the determination of the total current enclosed. The sensor is conformable to complex structure geometry. It is also non-conductive and immune to electromagnetic interference, saturation or hysteresis. Installation is non-intrusive, and the sensor can be safely routed through flammable areas. Two similar sensor systems are described in this paper. The first system operates at 1310nm laser wavelength and is capable of measuring approximately 300 A - 300 kA, a 60 dB range. Laboratory validation results of aircraft lighting direct and in-direct effect current amplitudes are reported for this sensor. The second system operates at 1550nm wavelength and can measure about 400 A - 400 kA. Triggered-lightning measurement data are presented for this system. Good results are achieved in all cases.

Infrared Thermography Approach for Effective Shielding Area of Field Smoke Based on Background Subtraction and Transmittance Interpolation.

PubMed

Tang, Runze; Zhang, Tonglai; Chen, Yongpeng; Liang, Hao; Li, Bingyang; Zhou, Zunning

2018-05-06

Effective shielding area is a crucial indicator for the evaluation of the infrared smoke-obscuring effectiveness on the battlefield. The conventional methods for assessing the shielding area of the smoke screen are time-consuming and labor intensive, in addition to lacking precision. Therefore, an efficient and convincing technique for testing the effective shielding area of the smoke screen has great potential benefits in the smoke screen applications in the field trial. In this study, a thermal infrared sensor with a mid-wavelength infrared (MWIR) range of 3 to 5 μm was first used to capture the target scene images through clear as well as obscuring smoke, at regular intervals. The background subtraction in motion detection was then applied to obtain the contour of the smoke cloud at each frame. The smoke transmittance at each pixel within the smoke contour was interpolated based on the data that was collected from the image. Finally, the smoke effective shielding area was calculated, based on the accumulation of the effective shielding pixel points. One advantage of this approach is that it utilizes only one thermal infrared sensor without any other additional equipment in the field trial, which significantly contributes to the efficiency and its convenience. Experiments have been carried out to demonstrate that this approach can determine the effective shielding area of the field infrared smoke both practically and efficiently.

High-speed line-scan camera with digital time delay integration

NASA Astrophysics Data System (ADS)

Bodenstorfer, Ernst; Fürtler, Johannes; Brodersen, Jörg; Mayer, Konrad J.; Eckel, Christian; Gravogl, Klaus; Nachtnebel, Herbert

2007-02-01

Dealing with high-speed image acquisition and processing systems, the speed of operation is often limited by the amount of available light, due to short exposure times. Therefore, high-speed applications often use line-scan cameras, based on charge-coupled device (CCD) sensors with time delayed integration (TDI). Synchronous shift and accumulation of photoelectric charges on the CCD chip - according to the objects' movement - result in a longer effective exposure time without introducing additional motion blur. This paper presents a high-speed color line-scan camera based on a commercial complementary metal oxide semiconductor (CMOS) area image sensor with a Bayer filter matrix and a field programmable gate array (FPGA). The camera implements a digital equivalent to the TDI effect exploited with CCD cameras. The proposed design benefits from the high frame rates of CMOS sensors and from the possibility of arbitrarily addressing the rows of the sensor's pixel array. For the digital TDI just a small number of rows are read out from the area sensor which are then shifted and accumulated according to the movement of the inspected objects. This paper gives a detailed description of the digital TDI algorithm implemented on the FPGA. Relevant aspects for the practical application are discussed and key features of the camera are listed.

Sensing sheet: the response of full-bridge strain sensors to thermal variations for detecting and characterizing cracks

NASA Astrophysics Data System (ADS)

Tung, S.-T.; Glisic, B.

2016-12-01

Sensing sheets based on large-area electronics consist of a dense array of unit strain sensors. This new technology has potential for becoming an effective and affordable monitoring tool that can identify, localize and quantify surface damage in structures. This research contributes to their development by investigating the response of full-bridge unit strain sensors to thermal variations. Overall, this investigation quantifies the effects of temperature on thin-film full-bridge strain sensors monitoring uncracked and cracked concrete. Additionally, an empirical formula is developed to estimate crack width given an observed strain change and a measured temperature change. This research led to the understanding of the behavior of full-bridge strain sensors installed on cracked concrete and exposed to temperature variations. It proves the concept of the sensing sheet and its suitability for application in environments with variable temperature.

Highly sensitive long-period fiber-grating strain sensor with low temperature sensitivity

NASA Astrophysics Data System (ADS)

Wang, Yi-Ping; Xiao, Limin; Wang, D. N.; Jin, Wei

2006-12-01

A long-period fiber-grating sensor with a high strain sensitivity of -7.6 pm/μɛ and a low temperature sensitivity of 3.91 pm/°C is fabricated by use of focused CO2 laser beam to carve periodic grooves on a large- mode-area photonic crystal fiber. Such a strain sensor can effectively reduce the cross-sensitivity between strain and temperature, and the temperature-induced strain error obtained is only 0.5 μɛ/°C without using temperature compensation.

Cognitive radio wireless sensor networks: applications, challenges and research trends.

PubMed

Joshi, Gyanendra Prasad; Nam, Seung Yeob; Kim, Sung Won

2013-08-22

A cognitive radio wireless sensor network is one of the candidate areas where cognitive techniques can be used for opportunistic spectrum access. Research in this area is still in its infancy, but it is progressing rapidly. The aim of this study is to classify the existing literature of this fast emerging application area of cognitive radio wireless sensor networks, highlight the key research that has already been undertaken, and indicate open problems. This paper describes the advantages of cognitive radio wireless sensor networks, the difference between ad hoc cognitive radio networks, wireless sensor networks, and cognitive radio wireless sensor networks, potential application areas of cognitive radio wireless sensor networks, challenges and research trend in cognitive radio wireless sensor networks. The sensing schemes suited for cognitive radio wireless sensor networks scenarios are discussed with an emphasis on cooperation and spectrum access methods that ensure the availability of the required QoS. Finally, this paper lists several open research challenges aimed at drawing the attention of the readers toward the important issues that need to be addressed before the vision of completely autonomous cognitive radio wireless sensor networks can be realized.

In situ ozone data for evaluation of the laser absorption spectrometer ozone remote sensor: 1979 southeastern Virginia urban plume study summer field program

NASA Technical Reports Server (NTRS)

Gregory, G. L.; Mcdougal, D. S.; Mathis, J. J., Jr.

1980-01-01

Ozone data from the 1979 Southeastern Virginia Urban Study (SEV-UPS) field program are presented. The SEV-UPS was conducted for evaluation of an ozone remote sensor, the Laser Absorption Spectrometer. During the measurement program, remote-sensor evaluation was in two areas; (1) determination of the remote sensor's accuracy, repeatability, and operational characteristics, and (2) demonstration of the application of remotely sensed ozone data in air-quality studies. Data from six experiments designed to provide in situ ozone data for evaluation of the sensor in area 1, above, are presented. Experiments consisted of overflights of a test area with the remote sensor aircraft while in situ measurements with a second aircraft and selected surface stations provided correlative ozone data within the viewing area of the remote sensor.

0.5 V and 0.43 pJ/bit Capacitive Sensor Interface for Passive Wireless Sensor Systems

PubMed Central

Beriain, Andoni; Gutierrez, Iñigo; Solar, Hector; Berenguer, Roc

2015-01-01

This paper presents an ultra low-power and low-voltage pulse-width modulation based ratiometric capacitive sensor interface. The interface was designed and fabricated in a standard 90 nm CMOS 1P9M technology. The measurements show an effective resolution of 10 bits using 0.5 V of supply voltage. The active occupied area is only 0.0045 mm2 and the Figure of Merit (FOM), which takes into account the energy required per conversion bit, is 0.43 pJ/bit. Furthermore, the results show low sensitivity to PVT variations due to the proposed ratiometric architecture. In addition, the sensor interface was connected to a commercial pressure transducer and the measurements of the resulting complete pressure sensor show a FOM of 0.226 pJ/bit with an effective linear resolution of 7.64 bits. The results validate the use of the proposed interface as part of a pressure sensor, and its low-power and low-voltage characteristics make it suitable for wireless sensor networks and low power consumer electronics. PMID:26343681

0.5 V and 0.43 pJ/bit Capacitive Sensor Interface for Passive Wireless Sensor Systems.

PubMed

Beriain, Andoni; Gutierrez, Iñigo; Solar, Hector; Berenguer, Roc

2015-08-28

This paper presents an ultra low-power and low-voltage pulse-width modulation based ratiometric capacitive sensor interface. The interface was designed and fabricated in a standard 90 nm CMOS 1P9M technology. The measurements show an effective resolution of 10 bits using 0.5 V of supply voltage. The active occupied area is only 0.0045 mm2 and the Figure of Merit (FOM), which takes into account the energy required per conversion bit, is 0.43 pJ/bit. Furthermore, the results show low sensitivity to PVT variations due to the proposed ratiometric architecture. In addition, the sensor interface was connected to a commercial pressure transducer and the measurements of the resulting complete pressure sensor show a FOM of 0.226 pJ/bit with an effective linear resolution of 7.64 bits. The results validate the use of the proposed interface as part of a pressure sensor, and its low-power and low-voltage characteristics make it suitable for wireless sensor networks and low power consumer electronics.

PASTIS 57: Autonomous light sensors for PAI continuous monitoring. Principles, calibration and application to vegetation phenology

NASA Astrophysics Data System (ADS)

Lecerf, R.; Baret, F.; Hanocq, J.; Marloie, O.; Rautiainen, M.; Mottus, M.; Heiskanen, J.; Stenberg, P.

2010-12-01

The LAI (Leaf Area Index) is a key variable to analyze and model vegetation and its interactions with atmosphere and soils. The LAI maps derived from remote sensing images are often validated with non-destructive LAI measures obtained from digital hemispherical photography, LAI-2000 or ceptometer instruments. These methods are expensive and time consuming particularly when human intervention is needed. Consequently it is difficult to acquire overlapping field data and remotely sensed LAI. There is a need of a cheap, autonomous, easy to use ground system to measure foliage development and senescence at least with a daily frequency in order to increase the number of validation sites where vegetation phenology is continuously monitored. A system called PASTIS-57 (PAI Autonomous System from Transmittance Instantaneous Sensors oriented at 57°) devoted to PAI (Plant Area Index) ground measurements was developed to answer this need. PASTIS-57 consists in 6 sensors plugged on one logger that record data with a sampling rate of 1 to few minutes (tunable) with up to 3 months autonomy (energy and data storage). The sensors are plugged to the logger with 2x10m wires, 2x6m wires and 2x2m wires. The distance between each sensor was determined to obtain a representative spatial sampling over a 20m pixel corresponding to an Elementary Sampling Unit (ESU). The PASTIS-57 sensors are made of photodiodes that measure the incoming light in the blue wavelength to maximize the contrast between vegetation and sky and limit multiple scattering effects in the canopy. The diodes are oriented to the north to avoid direct sun light and point to a zenithal angle of 57° to minimize leaf angle distribution and plant clumping effects. The field of view of the diodes was set to ± 20° to take into consideration vegetation cover heterogeneity and to minimize environmental effects. The sensors were calibrated after recording data on a clear view site during a week. After calibration, the sensors were installed on several study sites including a boreal forest in Finland and an agricultural area in southern France. On each study site, several ESUs were equipped with 2 to 4 systems. The sensors were installed along an East-West line and were pointing to the north. A reference system was set up to monitor unobstructed incident radiation field. The results show that the transmitted light recorded by sensors depends on gap fraction and may be used to measure the PAI (Plant Area Index). The time series acquired with the PASTIS-57 show strong correlation with plant phenology. The PAI values were then derived from the measured gap fractions. Advantages and limitations of the system are finally discussed with emphasis on potential operational use within networks of sites.

High speed three-dimensional laser scanner with real time processing

NASA Technical Reports Server (NTRS)

Lavelle, Joseph P. (Inventor); Schuet, Stefan R. (Inventor)

2008-01-01

A laser scanner computes a range from a laser line to an imaging sensor. The laser line illuminates a detail within an area covered by the imaging sensor, the area having a first dimension and a second dimension. The detail has a dimension perpendicular to the area. A traverse moves a laser emitter coupled to the imaging sensor, at a height above the area. The laser emitter is positioned at an offset along the scan direction with respect to the imaging sensor, and is oriented at a depression angle with respect to the area. The laser emitter projects the laser line along the second dimension of the area at a position where a image frame is acquired. The imaging sensor is sensitive to laser reflections from the detail produced by the laser line. The imaging sensor images the laser reflections from the detail to generate the image frame. A computer having a pipeline structure is connected to the imaging sensor for reception of the image frame, and for computing the range to the detail using height, depression angle and/or offset. The computer displays the range to the area and detail thereon covered by the image frame.

Analysis of Mission Effectiveness: Modern System Architecture Tools for Project Developers

DTIC Science & Technology

2017-12-01

operator input and scripted instructions to describe low-level flow. Note that the case study in Chapter IV describes one pass through evaluation...capability of the sensors. A constraint on the case study is that each sensor type must cover the entire operations area. Cost is a function of 53...completed. 5. Assessment This case study focuses on the first recursive refinement phase completed in a multi-phase effort to demonstrate the effects

Biomedical sensor technologies on the platform of mobile phones

NASA Astrophysics Data System (ADS)

Liu, Lin; Liu, Jing

2011-06-01

Biomedical sensors have been widely used in various areas of biomedical practices, which play an important role in disease detection, diagnosis, monitoring, treatment, health management, and so on. However, most of them and their related platforms are generally not easily accessible or just too expensive or complicated to be kept at home. As an alternative, new technologies enabled from the mobile phones are gradually changing such situations. As can be freely available to almost everyone, mobile phone offers a unique way to improve the conventional medical care through combining with various biomedical sensors. Moreover, the established systems will be both convenient and low cost. In this paper, we present an overview on the state-of-art biomedical sensors, giving a brief introduction of the fundamental principles and showing several new examples or concepts in the area. The focus was particularly put on interpreting the technical strategies to innovate the biomedical sensor technologies based on the platform of mobile phones. Some challenging issues, including feasibility, usability, security, and effectiveness, were discussed. With the help of electrical and mechanical technologies, it is expected that a full combination between the biomedical sensors and mobile phones will bring a bright future for the coming pervasive medical care.

Wireless Sensors and Networks for Advanced Energy Management

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hardy, J.E.

Numerous national studies and working groups have identified low-cost, very low-power wireless sensors and networks as a critical enabling technology for increasing energy efficiency, reducing waste, and optimizing processes. Research areas for developing such sensor and network platforms include microsensor arrays, ultra-low power electronics and signal conditioning, data/control transceivers, and robust wireless networks. A review of some of the research in the following areas will be discussed: (1) Low-cost, flexible multi-sensor array platforms (CO{sub 2}, NO{sub x}, CO, humidity, NH{sub 3}, O{sub 2}, occupancy, etc.) that enable energy and emission reductions in applications such as buildings and manufacturing; (2) Modelingmore » investments (energy usage and savings to drive capital investment decisions) and estimated uptime improvements through pervasive gathering of equipment and process health data and its effects on energy; (3) Robust, self-configuring wireless sensor networks for energy management; and (4) Quality-of-service for secure and reliable data transmission from widely distributed sensors. Wireless communications is poised to support technical innovations in the industrial community, with widespread use of wireless sensors forecasted to improve manufacturing production and energy efficiency and reduce emissions. Progress being made in wireless system components, as described in this paper, is helping bring these projected improvements to reality.« less

Peer-to-peer model for the area coverage and cooperative control of mobile sensor networks

NASA Astrophysics Data System (ADS)

Tan, Jindong; Xi, Ning

2004-09-01

This paper presents a novel model and distributed algorithms for the cooperation and redeployment of mobile sensor networks. A mobile sensor network composes of a collection of wireless connected mobile robots equipped with a variety of sensors. In such a sensor network, each mobile node has sensing, computation, communication, and locomotion capabilities. The locomotion ability enhances the autonomous deployment of the system. The system can be rapidly deployed to hostile environment, inaccessible terrains or disaster relief operations. The mobile sensor network is essentially a cooperative multiple robot system. This paper first presents a peer-to-peer model to define the relationship between neighboring communicating robots. Delaunay Triangulation and Voronoi diagrams are used to define the geometrical relationship between sensor nodes. This distributed model allows formal analysis for the fusion of spatio-temporal sensory information of the network. Based on the distributed model, this paper discusses a fault tolerant algorithm for autonomous self-deployment of the mobile robots. The algorithm considers the environment constraints, the presence of obstacles and the nonholonomic constraints of the robots. The distributed algorithm enables the system to reconfigure itself such that the area covered by the system can be enlarged. Simulation results have shown the effectiveness of the distributed model and deployment algorithms.

The capability of satellite borne remote sensors to measure stratospheric trace constituents. Volume 2: Ozone and aerosol related missions

NASA Technical Reports Server (NTRS)

Keitz, E. L.

1978-01-01

Stratospheric trace constituent measurement requirements are separated into two somewhat overlapping areas. In the first area, it is assumed that the only problem of interest is ozone; its chemistry chain, environmental effects and measurement requirements. In like manner, in the second area it is assumed that the only problem of interest is stratospheric aerosols; their chemistry, effects and measurement requirements.

Fusion of sensor geometry into additive strain fields measured with sensing skin

NASA Astrophysics Data System (ADS)

Downey, Austin; Sadoughi, Mohammadkazem; Laflamme, Simon; Hu, Chao

2018-07-01

Recently, numerous studies have been conducted on flexible skin-like membranes for the cost effective monitoring of large-scale structures. The authors have proposed a large-area electronic consisting of a soft elastomeric capacitor (SEC) that transduces a structure’s strain into a measurable change in capacitance. Arranged in a network configuration, SECs deployed onto the surface of a structure could be used to reconstruct strain maps. Several regression methods have been recently developed with the purpose of reconstructing such maps, but all these algorithms assumed that each SEC-measured strain located at its geometric center. This assumption may not be realistic since an SEC measures the average strain value of the whole area covered by the sensor. One solution is to reduce the size of each SEC, but this would also increase the number of required sensors needed to cover the large-scale structure, therefore increasing the need for the power and data acquisition capabilities. Instead, this study proposes an algorithm that accounts for the sensor’s strain averaging feature by adjusting the strain measurements and constructing a full-field strain map using the kriging interpolation method. The proposed algorithm fuses the geometry of an SEC sensor into the strain map reconstruction in order to adaptively adjust the average kriging-estimated strain of the area monitored by the sensor to the signal. Results show that by considering the sensor geometry, in addition to the sensor signal and location, the proposed strain map adjustment algorithm is capable of producing more accurate full-field strain maps than the traditional spatial interpolation method that considered only signal and location.

Broadband electromagnetic sensors for aircraft lightning research. [electromagnetic effects of lightning on aircraft digital equipment

NASA Technical Reports Server (NTRS)

Trost, T. F.; Zaepfel, K. P.

1980-01-01

A set of electromagnetic sensors, or electrically-small antennas, is described. The sensors are designed for installation on an F-106 research aircraft for the measurement of electric and magnetic fields and currents during a lightning strike. The electric and magnetic field sensors mount on the aircraft skin. The current sensor mounts between the nose boom and the fuselage. The sensors are all on the order of 10 cm in size and should produce up to about 100 V for the estimated lightning fields. The basic designs are the same as those developed for nuclear electromagnetic pulse studies. The most important electrical parameters of the sensors are the sensitivity, or equivalent area, and the bandwidth (or rise time). Calibration of sensors with simple geometries is reliably accomplished by a geometric analysis; all the sensors discussed possess geometries for which the sensitivities have been calculated. For the calibration of sensors with more complex geometries and for general testing of all sensors, two transmission lines were constructed to transmit known pulsed fields and currents over the sensors.

Integrated waveguide and nanostructured sensor platform for surface-enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Pearce, Stuart J.; Pollard, Michael E.; Oo, SweZin; Chen, Ruiqi; Kalsi, Sumit; Charlton, Martin D. B.

2014-01-01

Limitations of current sensors include large dimensions, sometimes limited sensitivity and inherent single-parameter measurement capability. Surface-enhanced Raman spectroscopy can be utilized for environment and pharmaceutical applications with the intensity of the Raman scattering enhanced by a factor of 10. By fabricating and characterizing an integrated optical waveguide beneath a nanostructured precious metal coated surface a new surface-enhanced Raman spectroscopy sensing arrangement can be achieved. Nanostructured sensors can provide both multiparameter and high-resolution sensing. Using the slab waveguide core to interrogate the nanostructures at the base allows for the emission to reach discrete sensing areas effectively and should provide ideal parameters for maximum Raman interactions. Thin slab waveguide films of silicon oxynitride were etched and gold coated to create localized nanostructured sensing areas of various pitch, diameter, and shape. These were interrogated using a Ti:Sapphire laser tuned to 785-nm end coupled into the slab waveguide. The nanostructured sensors vertically projected a Raman signal, which was used to actively detect a thin layer of benzyl mercaptan attached to the sensors.

Decentralized sensor fusion for Ubiquitous Networking Robotics in Urban Areas.

PubMed

Sanfeliu, Alberto; Andrade-Cetto, Juan; Barbosa, Marco; Bowden, Richard; Capitán, Jesús; Corominas, Andreu; Gilbert, Andrew; Illingworth, John; Merino, Luis; Mirats, Josep M; Moreno, Plínio; Ollero, Aníbal; Sequeira, João; Spaan, Matthijs T J

2010-01-01

In this article we explain the architecture for the environment and sensors that has been built for the European project URUS (Ubiquitous Networking Robotics in Urban Sites), a project whose objective is to develop an adaptable network robot architecture for cooperation between network robots and human beings and/or the environment in urban areas. The project goal is to deploy a team of robots in an urban area to give a set of services to a user community. This paper addresses the sensor architecture devised for URUS and the type of robots and sensors used, including environment sensors and sensors onboard the robots. Furthermore, we also explain how sensor fusion takes place to achieve urban outdoor execution of robotic services. Finally some results of the project related to the sensor network are highlighted.

Radiation area monitor device and method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vencelj, Matjaz; Stowe, Ashley C.; Petrovic, Toni

A radiation area monitor device/method, utilizing: a radiation sensor having a directional radiation sensing capability; a rotation mechanism operable for selectively rotating the radiation sensor such that the directional radiation sensing capability selectively sweeps an area of interest; and a processor operable for analyzing and storing a radiation fingerprint acquired by the radiation sensor as the directional radiation sensing capability selectively sweeps the area of interest. Optionally, the radiation sensor includes a gamma and/or neutron radiation sensor. The device/method selectively operates in: a first supervised mode during which a baseline radiation fingerprint is acquired by the radiation sensor; and amore » second unsupervised mode during which a subsequent radiation fingerprint is acquired by the radiation sensor, wherein the subsequent radiation fingerprint is compared to the baseline radiation fingerprint and, if a predetermined difference threshold is exceeded, an alert is issued.« less

Effects of annealing temperature on the H2-sensing properties of Pd-decorated WO3 nanorods

NASA Astrophysics Data System (ADS)

Lee, Sangmin; Lee, Woo Seok; Lee, Jae Kyung; Hyun, Soong Keun; Lee, Chongmu; Choi, Seungbok

2018-03-01

The temperature of the post-annealing treatment carried out after noble metal deposition onto semiconducting metal oxides (SMOs) must be carefully optimized to maximize the sensing performance of the metal-decorated SMO sensors. WO3 nanorods were synthesized by thermal evaporation of WO3 powders and decorated with Pd nanoparticles using a sol-gel method, followed by an annealing process. The effects of the annealing temperature on the hydrogen gas-sensing properties of the Pd-decorated WO3 nanorods were then examined; the optimal annealing temperature, leading to the highest response of the WO3 nanorod sensor to H2, was determined to be 600 °C. Post-annealing at 600 °C resulted in nanorods with the highest surface area-to-volume ratio, as well as in the optimal size and the largest number of deposited Pd nanoparticles, leading to the highest response and the shortest response/recovery times toward H2. The improved H2-sensing performance of the Pd-decorated WO3 nanorod sensor, compared to a sensor based on pristine WO3 nanorods, is attributed to the enhanced catalytic activity, increased surface area-to-volume ratio, and higher amounts of surface defects.

Autonomous management of a recursive area hierarchy for large scale wireless sensor networks using multiple parents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cree, Johnathan Vee; Delgado-Frias, Jose

Large scale wireless sensor networks have been proposed for applications ranging from anomaly detection in an environment to vehicle tracking. Many of these applications require the networks to be distributed across a large geographic area while supporting three to five year network lifetimes. In order to support these requirements large scale wireless sensor networks of duty-cycled devices need a method of efficient and effective autonomous configuration/maintenance. This method should gracefully handle the synchronization tasks duty-cycled networks. Further, an effective configuration solution needs to recognize that in-network data aggregation and analysis presents significant benefits to wireless sensor network and should configuremore » the network in a way such that said higher level functions benefit from the logically imposed structure. NOA, the proposed configuration and maintenance protocol, provides a multi-parent hierarchical logical structure for the network that reduces the synchronization workload. It also provides higher level functions with significant inherent benefits such as but not limited to: removing network divisions that are created by single-parent hierarchies, guarantees for when data will be compared in the hierarchy, and redundancies for communication as well as in-network data aggregation/analysis/storage.« less

The Area Coverage of Geophysical Fields as a Function of Sensor Field-of View

NASA Technical Reports Server (NTRS)

Key, Jeffrey R.

1994-01-01

In many remote sensing studies of geophysical fields such as clouds, land cover, or sea ice characteristics, the fractional area coverage of the field in an image is estimated as the proportion of pixels that have the characteristic of interest (i.e., are part of the field) as determined by some thresholding operation. The effect of sensor field-of-view on this estimate is examined by modeling the unknown distribution of subpixel area fraction with the beta distribution, whose two parameters depend upon the true fractional area coverage, the pixel size, and the spatial structure of the geophysical field. Since it is often not possible to relate digital number, reflectance, or temperature to subpixel area fraction, the statistical models described are used to determine the effect of pixel size and thresholding operations on the estimate of area fraction for hypothetical geophysical fields. Examples are given for simulated cumuliform clouds and linear openings in sea ice, whose spatial structures are described by an exponential autocovariance function. It is shown that the rate and direction of change in total area fraction with changing pixel size depends on the true area fraction, the spatial structure, and the thresholding operation used.

Optical fiber strain sensor for application in intelligent intruder detection systems

NASA Astrophysics Data System (ADS)

Stańczyk, Tomasz; Tenderenda, Tadeusz; Szostkiewicz, Lukasz; Bienkowska, Beata; Kunicki, Daniel; Murawski, Michal; Mergo, Pawel; Nasilowski, Tomasz

2017-10-01

Nowadays technology allows to create highly effective Intruder Detection Systems (IDS), that are able to detect the presence of an intruder within a defined area. In such systems the best performance can be achieved by combining different detection techniques in one system. One group of devices that can be applied in an IDS, are devices based on Fiber Optic Sensors (FOS). The FOS benefits from numerous advantages of optical fibers like: small size, light weight or high sensitivity. In this work we present a novel Microstructured Optical Fiber (MOF) characterized by increased strain sensitivity dedicated to distributed acoustic sensing for intelligent intruder detection systems. By designing the MOF with large air holes in close proximity to a fiber core, we increased the effective refractive index sensitivity to longitudinal strain. The presented fiber can be easily integrated in a floor system in order to detect any movement in the investigated area. We believe that sensors, based on the presented MOF, due to its numerous advantages, can find application in intelligent IDS.

Dust Sensor with Large Detection Area Using Polyimide Film and Piezoelectric Elements

NASA Astrophysics Data System (ADS)

Kobayashi, M.; Okudaira, O.; Kurosawa, K.; Okamoto, T.; Matsui, T.

2016-10-01

We describe the development of dust particles sensor in space with large area (1m × 1m scale). The sensor has just a thin film of polyimide attached with small tips of piezoelectric elements. We performed experiments to characterize the sensor.

Reconfigurable intelligent sensors for health monitoring: a case study of pulse oximeter sensor.

PubMed

Jovanov, E; Milenkovic, A; Basham, S; Clark, D; Kelley, D

2004-01-01

Design of low-cost, miniature, lightweight, ultra low-power, intelligent sensors capable of customization and seamless integration into a body area network for health monitoring applications presents one of the most challenging tasks for system designers. To answer this challenge we propose a reconfigurable intelligent sensor platform featuring a low-power microcontroller, a low-power programmable logic device, a communication interface, and a signal conditioning circuit. The proposed solution promises a cost-effective, flexible platform that allows easy customization, run-time reconfiguration, and energy-efficient computation and communication. The development of a common platform for multiple physical sensors and a repository of both software procedures and soft intellectual property cores for hardware acceleration will increase reuse and alleviate costs of transition to a new generation of sensors. As a case study, we present an implementation of a reconfigurable pulse oximeter sensor.

Cognitive Radio Wireless Sensor Networks: Applications, Challenges and Research Trends

PubMed Central

Joshi, Gyanendra Prasad; Nam, Seung Yeob; Kim, Sung Won

2013-01-01

A cognitive radio wireless sensor network is one of the candidate areas where cognitive techniques can be used for opportunistic spectrum access. Research in this area is still in its infancy, but it is progressing rapidly. The aim of this study is to classify the existing literature of this fast emerging application area of cognitive radio wireless sensor networks, highlight the key research that has already been undertaken, and indicate open problems. This paper describes the advantages of cognitive radio wireless sensor networks, the difference between ad hoc cognitive radio networks, wireless sensor networks, and cognitive radio wireless sensor networks, potential application areas of cognitive radio wireless sensor networks, challenges and research trend in cognitive radio wireless sensor networks. The sensing schemes suited for cognitive radio wireless sensor networks scenarios are discussed with an emphasis on cooperation and spectrum access methods that ensure the availability of the required QoS. Finally, this paper lists several open research challenges aimed at drawing the attention of the readers toward the important issues that need to be addressed before the vision of completely autonomous cognitive radio wireless sensor networks can be realized. PMID:23974152

Unified Compact ECC-AES Co-Processor with Group-Key Support for IoT Devices in Wireless Sensor Networks

PubMed Central

Castillo, Encarnación; López-Ramos, Juan A.; Morales, Diego P.

2018-01-01

Security is a critical challenge for the effective expansion of all new emerging applications in the Internet of Things paradigm. Therefore, it is necessary to define and implement different mechanisms for guaranteeing security and privacy of data interchanged within the multiple wireless sensor networks being part of the Internet of Things. However, in this context, low power and low area are required, limiting the resources available for security and thus hindering the implementation of adequate security protocols. Group keys can save resources and communications bandwidth, but should be combined with public key cryptography to be really secure. In this paper, a compact and unified co-processor for enabling Elliptic Curve Cryptography along to Advanced Encryption Standard with low area requirements and Group-Key support is presented. The designed co-processor allows securing wireless sensor networks with independence of the communications protocols used. With an area occupancy of only 2101 LUTs over Spartan 6 devices from Xilinx, it requires 15% less area while achieving near 490% better performance when compared to cryptoprocessors with similar features in the literature. PMID:29337921

Unified Compact ECC-AES Co-Processor with Group-Key Support for IoT Devices in Wireless Sensor Networks.

PubMed

Parrilla, Luis; Castillo, Encarnación; López-Ramos, Juan A; Álvarez-Bermejo, José A; García, Antonio; Morales, Diego P

2018-01-16

Security is a critical challenge for the effective expansion of all new emerging applications in the Internet of Things paradigm. Therefore, it is necessary to define and implement different mechanisms for guaranteeing security and privacy of data interchanged within the multiple wireless sensor networks being part of the Internet of Things. However, in this context, low power and low area are required, limiting the resources available for security and thus hindering the implementation of adequate security protocols. Group keys can save resources and communications bandwidth, but should be combined with public key cryptography to be really secure. In this paper, a compact and unified co-processor for enabling Elliptic Curve Cryptography along to Advanced Encryption Standard with low area requirements and Group-Key support is presented. The designed co-processor allows securing wireless sensor networks with independence of the communications protocols used. With an area occupancy of only 2101 LUTs over Spartan 6 devices from Xilinx, it requires 15% less area while achieving near 490% better performance when compared to cryptoprocessors with similar features in the literature.

Morphological, structural, and chemical effects in response of novel carbide derived carbon sensor to NH3, N2O, and air.

PubMed

Adu, Kofi W; Li, Qixiu; Desai, Sharvil C; Sidorov, Anton N; Sumanasekera, Gamini U; Lueking, Angela D

2009-01-06

The response of two carbide derived carbons (CDCs) films to NH(3), N(2)O, and room air is investigated by four probe resistance at room temperature and pressures up to 760 Torr. The two CDC films were synthesized at 600 (CDC-600) and 1000 degrees C (CDC-1000) to vary the carbon morphology from completely amorphous to more ordered, and determine the role of structure, surface area, and porosity on sensor response. Sensor response time followed kinetic diameter and indicated a more ordered carbon structure slowed response due to increased tortuosity caused by the formation of graphitic layers at the particle fringe. Steady state sensor response was greater for the less-ordered material, despite its decreased surface area, decreased micropore volume, and less favorable surface chemistry, suggesting carbon structure is a stronger predictor of sensor response than surface chemistry. The lack of correlation between adsorption of the probe gases and sensor response suggests chemical interaction (charge transfer) drive sensor response within the material; N(2)O response, in particular, did not follow simple adsorption behavior. Based on Raman and FTIR characterization, carbon morphology (disorder) appeared to be the determining factor in overall sensor response, likely due to increased charge transfer between gases and carbon defects of amorphous or disordered regions. The response of the amorphous CDC-600 film to NH(3) was 45% without prior oxidation, showing amorphous CDCs have promise as chemical sensors without additional pretreatment common to other carbon sensors.

Skylab program earth resouces experiment package. Volume 4: Sensor performance evaluation (S193 R/S). [radiometer/scatterometer

NASA Technical Reports Server (NTRS)

Kenney, G. P.

1975-01-01

The results of the sensor performance evaluation of the 13.9 GHz radiometer/scatterometer, which was part of the earth resources experiment package on Skylab. Findings are presented in the areas of housekeeping parameters, antenna gain and scanning performance, dynamic range, linearity, precision, resolution, stability, integration time, and transmitter output. Supplementary analyses covering performance anomalies, data stream peculiarities, aircraft sensor data comparisons, scatterometer saturation characteristics, and RF heating effects are reported. Results of the evaluation show that instrument performance was generally as expected, but capability degradations were observed to result from three major anomalies. Conclusions are drawn from the evaluation results, and recommendations for improving the effectiveness of a future program are offered. An addendum describes the special evaluation techniques developed and applied in the sensor performance evaluation tasks.

Environmental Site Characterization for the Wide Area Mine Sensor Demonstration, Aberdeen Proving Ground, October 1988

DTIC Science & Technology

1991-05-01

AD-A237 045 MP I ENVIRONMENTAL SITE CHARACTERIZATION of EFOR THE WIDE AREA MINE SENSOR DEMONSTRATION, ABERDEEN PROVING GROUND , OCTOBER 1988 T- by...Wide Area Mine Sensor Demonstration, Aberdeen Proving Ground , October 1988 6. AUTHOR(S) Bruce M. Sabol, Thomas E. Berry, Ben L. Garnes 7. PERFORMING... Proving Ground (APG), Maryland. This report presents data that characterize terrain and environmental factors expected to affect WAN sensor performance

Decentralized Sensor Fusion for Ubiquitous Networking Robotics in Urban Areas

PubMed Central

Sanfeliu, Alberto; Andrade-Cetto, Juan; Barbosa, Marco; Bowden, Richard; Capitán, Jesús; Corominas, Andreu; Gilbert, Andrew; Illingworth, John; Merino, Luis; Mirats, Josep M.; Moreno, Plínio; Ollero, Aníbal; Sequeira, João; Spaan, Matthijs T.J.

2010-01-01

In this article we explain the architecture for the environment and sensors that has been built for the European project URUS (Ubiquitous Networking Robotics in Urban Sites), a project whose objective is to develop an adaptable network robot architecture for cooperation between network robots and human beings and/or the environment in urban areas. The project goal is to deploy a team of robots in an urban area to give a set of services to a user community. This paper addresses the sensor architecture devised for URUS and the type of robots and sensors used, including environment sensors and sensors onboard the robots. Furthermore, we also explain how sensor fusion takes place to achieve urban outdoor execution of robotic services. Finally some results of the project related to the sensor network are highlighted. PMID:22294927

Hydrogen gas sensing feature of polyaniline/titania (rutile) nanocomposite at environmental conditions

NASA Astrophysics Data System (ADS)

Milani Moghaddam, Hossain; Nasirian, Shahruz

2014-10-01

The resistance-based sensors of polyaniline/titania (rutile) nanocomposite (TPNC) were prepared by spin coating technique onto an epoxy glass substrate with Cu-interdigited electrodes to study their hydrogen (H2) gas sensing features. Our findings are that the change of the surface morphology, porosity and wt% of titania in TPNCs have a significant effect on H2 gas sensing of sensors. All of the sensors had a reproducibility response toward 0.8 vol% H2 gas at room temperature, air pressure and 50% relative humidity. A sensor with 40 wt% of titania nanoparticles had better response/recovery time and the response than other sensors. Moreover, H2 gas sensing mechanism of TPNC sensors based contact areas and the correlation of energy levels between PANI chains and the titania grains were studied.

Detecting Traversable Area and Water Hazards for the Visually Impaired with a pRGB-D Sensor

PubMed Central

Yang, Kailun; Wang, Kaiwei; Cheng, Ruiqi; Hu, Weijian; Huang, Xiao; Bai, Jian

2017-01-01

The use of RGB-Depth (RGB-D) sensors for assisting visually impaired people (VIP) has been widely reported as they offer portability, function-diversity and cost-effectiveness. However, polarization cues to assist traversability awareness without precautions against stepping into water areas are weak. In this paper, a polarized RGB-Depth (pRGB-D) framework is proposed to detect traversable area and water hazards simultaneously with polarization-color-depth-attitude information to enhance safety during navigation. The approach has been tested on a pRGB-D dataset, which is built for tuning parameters and evaluating the performance. Moreover, the approach has been integrated into a wearable prototype which generates a stereo sound feedback to guide visually impaired people (VIP) follow the prioritized direction to avoid obstacles and water hazards. Furthermore, a preliminary study with ten blindfolded participants suggests its effectivity and reliability. PMID:28817069

Observation of rocket pollution with overhead sensors

NASA Astrophysics Data System (ADS)

Fisher, Annette

2011-12-01

The objective of this thesis is to study the dispersal of rocket pollution through remote sensing techniques. Substantial research with remote sensors has been dedicated to observation of volcanic plumes, particulate dispersion, and aircraft contrails with less emphasis on observing rocket launches and the effects on the surrounding environment. This research focuses on observation of rocket exhaust constituents, particularly carbon soot, alumina, and water vapor. The sensors utilized in this thesis have unique capabilities that provide measurements that are likely capable of detecting the rocket exhaust constituents. Methodology and analysis included choosing an appropriate launch vehicle with obtainable launch data and various booster combinations of liquid propellant only or a combination of liquid and solid propellant, prioritizing the data based on launch time versus sensor passing, processing the data, and applying known constituent properties to the data sets where key areas of work in this endeavor. Results of this work demonstrate a unique capability in monitoring man-made pollution and the extent the pollution can spread to surrounding areas.

A small, lightweight multipollutant sensor system for ground-mobile and aerial emission sampling from open area sources

NASA Astrophysics Data System (ADS)

Zhou, Xiaochi; Aurell, Johanna; Mitchell, William; Tabor, Dennis; Gullett, Brian

2017-04-01

Characterizing highly dynamic, transient, and vertically lofted emissions from open area sources poses unique measurement challenges. This study developed and applied a multipollutant sensor and time-integrated sampler system for use on mobile applications such as vehicles, tethered balloons (aerostats) and unmanned aerial vehicles (UAVs) to determine emission factors. The system is particularly applicable to open area sources, such as forest fires, due to its light weight (3.5 kg), compact size (6.75 L), and internal power supply. The sensor system, termed ;Kolibri;, consists of sensors measuring CO2 and CO, and samplers for particulate matter (PM) and volatile organic compounds (VOCs). The Kolibri is controlled by a microcontroller which can record and transfer data in real time through a radio module. Selection of the sensors was based on laboratory testing for accuracy, response delay and recovery, cross-sensitivity, and precision. The Kolibri was compared against rack-mounted continuous emissions monitoring system (CEMs) and another mobile sampling instrument (the ;Flyer;) that has been used in over ten open area pollutant sampling events. Our results showed that the time series of CO, CO2, and PM2.5 concentrations measured by the Kolibri agreed well with those from the CEMs and the Flyer, with a laboratory-tested percentage error of 4.9%, 3%, and 5.8%, respectively. The VOC emission factors obtained using the Kolibri were consistent with existing literature values that relate concentration to modified combustion efficiency. The potential effect of rotor downwash on particle sampling was investigated in an indoor laboratory and the preliminary results suggested that its influence is minimal. Field application of the Kolibri sampling open detonation plumes indicated that the CO and CO2 sensors responded dynamically and their concentrations co-varied with emission transients. The Kolibri system can be applied to various challenging open area scenarios such as fires, lagoons, flares, and landfills.

"Cut-and-Paste" Manufacture of Multiparametric Epidermal Sensor Systems.

PubMed

Yang, Shixuan; Chen, Ying-Chen; Nicolini, Luke; Pasupathy, Praveenkumar; Sacks, Jacob; Su, Becky; Yang, Russell; Sanchez, Daniel; Chang, Yao-Feng; Wang, Pulin; Schnyer, David; Neikirk, Dean; Lu, Nanshu

2015-11-04

Multifunctional epidermal sensor systems (ESS) are manufactured with a highly cost and time effective, benchtop, and large-area "cut-and-paste" method. The ESS made out of thin and stretchable metal and conductive polymer ribbons can be noninvasively laminated onto the skin surface to sense electrophysiological signals, skin temperature, skin hydration, and respiratory rate. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bio-Inspired Stretchable Absolute Pressure Sensor Network

PubMed Central

Guo, Yue; Li, Yu-Hung; Guo, Zhiqiang; Kim, Kyunglok; Chang, Fu-Kuo; Wang, Shan X.

2016-01-01

A bio-inspired absolute pressure sensor network has been developed. Absolute pressure sensors, distributed on multiple silicon islands, are connected as a network by stretchable polyimide wires. This sensor network, made on a 4’’ wafer, has 77 nodes and can be mounted on various curved surfaces to cover an area up to 0.64 m × 0.64 m, which is 100 times larger than its original size. Due to Micro Electro-Mechanical system (MEMS) surface micromachining technology, ultrathin sensing nodes can be realized with thicknesses of less than 100 µm. Additionally, good linearity and high sensitivity (~14 mV/V/bar) have been achieved. Since the MEMS sensor process has also been well integrated with a flexible polymer substrate process, the entire sensor network can be fabricated in a time-efficient and cost-effective manner. Moreover, an accurate pressure contour can be obtained from the sensor network. Therefore, this absolute pressure sensor network holds significant promise for smart vehicle applications, especially for unmanned aerial vehicles. PMID:26729134

Development and evaluation of a lightweight sensor system for aerial emission sampling from open area sources

EPA Science Inventory

A new sensor system for mobile and aerial emission sampling was developed for open area pollutant sources, such as prescribed forest burns. The sensor system, termed “Kolibri”, consists of multiple low-cost air quality sensors measuring CO2, CO, samplers for particulate matter wi...

Development and evaluation of a lightweight sensor system for aerial emission sampling from open area sources (Abstract)

EPA Science Inventory

A new sensor system for mobile and aerial emission sampling was developed for open area pollutant sources, such as prescribed forest burns. The sensor system, termed “Kolibri”, consists of multiple low-cost air quality sensors measuring CO2, CO, samplers for particulate matter wi...

Development and evaluation of a lightweight sensor system for emission sampling from open area sources

EPA Science Inventory

A new sensor system for mobile and aerial emission sampling was developed for open area sources, such as open burning. The sensor system, termed “Kolibri”, consists of multiple low-cost air quality sensors measuring CO2, CO, and black carbon, samplers for particulate matter with ...

High-resolution dynamic pressure sensor array based on piezo-phototronic effect tuned photoluminescence imaging.

PubMed

Peng, Mingzeng; Li, Zhou; Liu, Caihong; Zheng, Qiang; Shi, Xieqing; Song, Ming; Zhang, Yang; Du, Shiyu; Zhai, Junyi; Wang, Zhong Lin

2015-03-24

A high-resolution dynamic tactile/pressure display is indispensable to the comprehensive perception of force/mechanical stimulations such as electronic skin, biomechanical imaging/analysis, or personalized signatures. Here, we present a dynamic pressure sensor array based on pressure/strain tuned photoluminescence imaging without the need for electricity. Each sensor is a nanopillar that consists of InGaN/GaN multiple quantum wells. Its photoluminescence intensity can be modulated dramatically and linearly by small strain (0-0.15%) owing to the piezo-phototronic effect. The sensor array has a high pixel density of 6350 dpi and exceptional small standard deviation of photoluminescence. High-quality tactile/pressure sensing distribution can be real-time recorded by parallel photoluminescence imaging without any cross-talk. The sensor array can be inexpensively fabricated over large areas by semiconductor product lines. The proposed dynamic all-optical pressure imaging with excellent resolution, high sensitivity, good uniformity, and ultrafast response time offers a suitable way for smart sensing, micro/nano-opto-electromechanical systems.

Advanced Sensors and Applications Study (ASAS)

NASA Technical Reports Server (NTRS)

Chism, S. B.; Hughes, C. L.

1976-01-01

The present EOD requirements for sensors in the space shuttle era are reported with emphasis on those applications which were deemed important enough to warrant separate sections. The application areas developed are: (1) agriculture; (2) atmospheric corrections; (3) cartography; (4) coastal studies; (5) forestry; (6) geology; (7) hydrology; (8) land use; (9) oceanography; and (10) soil moisture. For each application area. The following aspects were covered: (1) specific goals and techniques, (2) individual sensor requirements including types, bands, resolution, etc.; (3) definition of mission requirements, type orbits, coverages, etc.; and (4) discussion of anticipated problem areas and solutions. The remote sensors required for these application areas include; (1) camera systems; (2) multispectral scanners; (3) microwave scatterometers; (4) synthetic aperture radars; (5) microwave radiometers; and (6) vidicons. The emphasis in the remote sensor area was on the evaluation of present technology implications about future systems.

Ability of Impedance-Based Health Monitoring To Detect Structural Damage of Propulsion System Components Assessed

NASA Technical Reports Server (NTRS)

Martin, Richard E.; Gyekenyesi, Andrew L.; Sawicki, Jerzy T.; Baaklini, George Y.

2005-01-01

Impedance-based structural-health-monitoring uses piezoelectric (PZT) patches that are bonded onto or embedded in a structure. Each individual patch behaves as both an actuator of the surrounding structural area as well as a sensor of the structural response. The size of the excited area varies with the geometry and material composition of the structure, and an active patch is driven by a sinusoidal voltage sweep. When a PZT patch is subjected to an electric field, it produces a mechanical strain; and when it is stressed, it produces an electric charge. Since the patch is bonded to the structure, driving a patch deforms and vibrates the structure. The structure then produces a localized dynamic response. This structural system response is transferred back to the PZT patch, which in turn produces an electrical response. The electromechanical impedance method is based on the principle of electromechanical coupling between the active sensor and the structure, which allows researchers to assess local structural dynamics directly by interrogating a distributed sensor array. Because of mechanical coupling between the sensor and the host structure, this mechanical effect is picked up by the sensor and, through electromechanical coupling inside the active element, is reflected in electrical impedance measured at the sensor s terminals.

Near-Real-Time Earth Observation Data Supporting Wildfire Management

NASA Astrophysics Data System (ADS)

Ambrosia, V. G.; Zajkowski, T.; Quayle, B.

2013-12-01

During disaster events, the most critical element needed by responding personnel and management teams is situational intelligence / awareness. During rapidly-evolving events such as wildfires, the need for timely information is critical to save lives, property and resources. The wildfire management agencies in the US rely heavily on remote sensing information both from airborne platforms as well as from orbital assets. The ability to readily have information from those systems, not just data, is critical to effective control and damage mitigation. NASA has been collaborating with the USFS to mature and operationalize various asset-information capabilities to effect improved knowledge of fire-prone areas, monitor wildfire events in real-time, assess effectiveness of fire management strategies, and provide rapid, post-fire assessment for recovery operations. Specific examples of near-real-time remote sensing asset utility include daily MODIS data employed to assess fire potential / wildfire hazard areas, and national-scale hot-spot detection, airborne thermal sensor collected during wildfire events to effect management strategies, EO-1 ALI 'pointable' satellite sensor data to assess fire-retardant application effectiveness, and Landsat 8 and other sensor data to derive burn severity indices for post-fire remediation work. These cases of where near-real-time data is used operationally during the previous few fire seasons will be presented.

An integrated biomedical telemetry system for sleep monitoring employing a portable body area network of sensors (SENSATION).

PubMed

Astaras, Alexander; Arvanitidou, Marina; Chouvarda, Ioanna; Kilintzis, Vassilis; Koutkias, Vassilis; Sanchez, Eduardo Monton; Stalidis, George; Triantafyllidis, Andreas; Maglaveras, Nicos

2008-01-01

A flexible, scaleable and cost-effective medical telemetry system is described for monitoring sleep-related disorders in the home environment. The system was designed and built for real-time data acquisition and processing, allowing for additional use in intensive care unit scenarios where rapid medical response is required in case of emergency. It comprises a wearable body area network of Zigbee-compatible wireless sensors worn by the subject, a central database repository residing in the medical centre and thin client workstations located at the subject's home and in the clinician's office. The system supports heterogeneous setup configurations, involving a variety of data acquisition sensors to suit several medical applications. All telemetry data is securely transferred and stored in the central database under the clinicians' ownership and control.

Sensors, Volume 1, Fundamentals and General Aspects

NASA Astrophysics Data System (ADS)

Grandke, Thomas; Ko, Wen H.

1996-12-01

'Sensors' is the first self-contained series to deal with the whole area of sensors. It describes general aspects, technical and physical fundamentals, construction, function, applications and developments of the various types of sensors. This volume deals with the fundamentals and common principles of sensors and covers the wide areas of principles, technologies, signal processing, and applications. Contents include: Sensor Fundamentals, e.g. Sensor Parameters, Modeling, Design and Packaging; Basic Sensor Technologies, e.g. Thin and Thick Films, Integrated Magnetic Sensors, Optical Fibres and Intergrated Optics, Ceramics and Oxides; Sensor Interfaces, e.g. Signal Processing, Multisensor Signal Processing, Smart Sensors, Interface Systems; Sensor Applications, e.g. Automotive: On-board Sensors, Traffic Surveillance and Control, Home Appliances, Environmental Monitoring, etc. This volume is an indispensable reference work and text book for both specialits and newcomers, researchers and developers.

A radar-enabled collaborative sensor network integrating COTS technology for surveillance and tracking.

PubMed

Kozma, Robert; Wang, Lan; Iftekharuddin, Khan; McCracken, Ernest; Khan, Muhammad; Islam, Khandakar; Bhurtel, Sushil R; Demirer, R Murat

2012-01-01

The feasibility of using Commercial Off-The-Shelf (COTS) sensor nodes is studied in a distributed network, aiming at dynamic surveillance and tracking of ground targets. Data acquisition by low-cost (<$50 US) miniature low-power radar through a wireless mote is described. We demonstrate the detection, ranging and velocity estimation, classification and tracking capabilities of the mini-radar, and compare results to simulations and manual measurements. Furthermore, we supplement the radar output with other sensor modalities, such as acoustic and vibration sensors. This method provides innovative solutions for detecting, identifying, and tracking vehicles and dismounts over a wide area in noisy conditions. This study presents a step towards distributed intelligent decision support and demonstrates effectiveness of small cheap sensors, which can complement advanced technologies in certain real-life scenarios.

Evaluation of communication in wireless underground sensor networks

NASA Astrophysics Data System (ADS)

Yu, X. Q.; Zhang, Z. L.; Han, W. T.

2017-06-01

Wireless underground sensor networks (WUSN) are an emerging area of research that promises to provide communication capabilities to buried sensors. In this paper, experimental measurements have been conducted with commodity sensor motes at the frequency of 2.4GHz and 433 MHz, respectively. Experiments are run to examine the received signal strength of correctly received packets and the packet error rate for a communication link. The tests show the potential feasibility of the WUSN with the use of powerful RF transceivers at 433MHz frequency. Moreover, we also illustrate a classification for wireless underground sensor network communication. Finally, we conclude that the effects of burial depth, inter-node distance and volumetric water content of the soil on the signal strength and packet error rate in communication of WUSN.

Deployment of Low-Cost, Carbon Dioxide Sensors throughout the Washington Metropolitan Area - The Capital Climate Initiative

NASA Astrophysics Data System (ADS)

Caine, Kristen M.; Bailey, D. Michelle; Houston Miller, J.

2016-04-01

According to the IPCC from 1995 to 2005, atmospheric carbon dioxide (CO2) concentrations increased by 19 ppm, the highest average growth rate recorded for any decade since measurements began in the 1950s. Due to its ability to influence global climate change, it is imperative to continually monitor carbon dioxide emission levels, particularly in urban areas where some estimate in excess of 75% of total greenhouse gas emissions occur. Although high-precision sensors are commercially available, these are not cost effective for mapping a large spatial area. A goal of this research is to build out a network of sensors that are accurate and precise enough to provide a valuable data tool for accessing carbon emissions from a large, urban area. This publically available greenhouse gas dataset can be used in numerous environmental assessments and as validation for remote sensing products. It will also be a valuable teaching tool for classes at our university and will promote further engagement of K-12 students and their teachers through education and outreach activities. Each of our sensors (referred to as "PiOxides") utilizes a non-dispersive infrared (NDIR) sensor for the detection of carbon dioxide along with a combination pressure/temperature/humidity sensor. The collection of pressure and temperature increases the accuracy and precision of the CO2 measurement. The sensors communicate using a serial interfaces with a Raspberry Pi microcontroller. Each PiOxide is connected to a website that leverages recent developments in open source GIS tools. In this way, data from individual sensors can be followed individually or aggregated to provide real-time, spatially-resolved data of CO2 trends across a broad area. Our goal for the network is to expand across the entire DC/Maryland/Virginia Region through partnerships with private and public schools. We are also designing GHG Bluetooth beacons that may be accessed by mobile phone users in their vicinity. In two additional applications, PiOxides are being deployed as a part of an innovative open networking platform being installed on LED street lights in Washington, DC and in a black spruce forest near Fairbanks, Alaska for the detection of carbon dioxide above thawing permafrost.

Development of autonomous magnetometer rotorcraft for wide area assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roelof Versteeg; Matt Anderson; Les Beard

2010-04-01

Large areas across the United States are potentially contaminated with UXO, with some ranges encompassing tens to hundreds of thousands of acres. Technologies are needed which will allow for cost effective wide area scanning with 1) near 100 % coverage and 2) near 100 % detection of subsurface ordnance or features indicative of subsurface ordnance. The current approach to wide area assessment is a multi-level one, in which medium - altitude fixed wing optical imaging is used for an initial site assessment. This assessment is followed with low altitude manned helicopter based magnetometry. Subsequent to this wide area assessment targetedmore » surface investigations are performed using either towed geophysical sensor arrays or man portable sensors. In order to be an effective tool for small UXO detection, the sensing altitude for magnetic site investigations needs to be on the order of 1 – 3 meters. These altitude requirements mean that manned helicopter surveys will generally only be feasible in large, open and relatively flat terrains. While such surveys are effective in mapping large areas relatively fast there are substantial mobilization/demobilization, staffing and equipment costs associated with these surveys (resulting in costs of approximately $100-$150/acre). In addition, due to the low altitude there are substantial risks to pilots and equipment. Surface towed arrays provide high resolution maps but have other limitations, e.g. in their ability to navigate rough terrain effectively. There is thus a need for other systems which can be used for effective data collection. An UAV (Unmanned Aerial Vehicle) magnetometer platform is an obvious alternative. The motivation behind such a system is that it reduces risk to operators, is lower in initial and Operational and Maintenance (O&M) costs (and can thus potentially be applied to smaller sites) and has the potential of being more effective in terms of detection and possibly characterization (through the use of dynamic acquisition, i.e. survey mission inflight reprioritization). We describe and report on a one year effort with as primary goal to provide a recommendation to SERDP for a path forward in the implementation of one or more autonomous unmanned magnetometer rotorcraft platforms. This recommendation (which is provided in chapter 6) is based on the following three elements a) An assessment on the applicability of autonomous rotorcraft magnetometer systems to the current DoD site inventory, and an initial assessment of which type(s) of autonomous unmanned magnetometer rotorcraft platforms (in terms of performance characteristics such as payload, altitude, obstacle avoidance, production rate and flight time) would be most relevant to this inventory (chapter 3); b) An evaluation of the feasibility of assembling such platforms from commercial components (unmanned rotorcraft, control systems and sensors – both magnetometer sensors and supporting sensors). This evaluation included several highly successful field tests (chapter 4 and 5); c) A recommendation of the path forward, which includes a detailed outline of the efforts required in the design, assembly and testing of different modular platforms (chapter 6)« less

Hybrid architecture for building secure sensor networks

NASA Astrophysics Data System (ADS)

Owens, Ken R., Jr.; Watkins, Steve E.

2012-04-01

Sensor networks have various communication and security architectural concerns. Three approaches are defined to address these concerns for sensor networks. The first area is the utilization of new computing architectures that leverage embedded virtualization software on the sensor. Deploying a small, embedded virtualization operating system on the sensor nodes that is designed to communicate to low-cost cloud computing infrastructure in the network is the foundation to delivering low-cost, secure sensor networks. The second area focuses on securing the sensor. Sensor security components include developing an identification scheme, and leveraging authentication algorithms and protocols that address security assurance within the physical, communication network, and application layers. This function will primarily be accomplished through encrypting the communication channel and integrating sensor network firewall and intrusion detection/prevention components to the sensor network architecture. Hence, sensor networks will be able to maintain high levels of security. The third area addresses the real-time and high priority nature of the data that sensor networks collect. This function requires that a quality-of-service (QoS) definition and algorithm be developed for delivering the right data at the right time. A hybrid architecture is proposed that combines software and hardware features to handle network traffic with diverse QoS requirements.

A Group Neighborhood Average Clock Synchronization Protocol for Wireless Sensor Networks

PubMed Central

Lin, Lin; Ma, Shiwei; Ma, Maode

2014-01-01

Clock synchronization is a very important issue for the applications of wireless sensor networks. The sensors need to keep a strict clock so that users can know exactly what happens in the monitoring area at the same time. This paper proposes a novel internal distributed clock synchronization solution using group neighborhood average. Each sensor node collects the offset and skew rate of the neighbors. Group averaging of offset and skew rate value are calculated instead of conventional point-to-point averaging method. The sensor node then returns compensated value back to the neighbors. The propagation delay is considered and compensated. The analytical analysis of offset and skew compensation is presented. Simulation results validate the effectiveness of the protocol and reveal that the protocol allows sensor networks to quickly establish a consensus clock and maintain a small deviation from the consensus clock. PMID:25120163

Study of optical techniques for the Ames unitary wind tunnels. Part 3: Angle of attack

NASA Technical Reports Server (NTRS)

Lee, George

1992-01-01

A review of optical sensors that are capable of accurate angle of attack measurements in wind tunnels was conducted. These include sensors being used or being developed at NASA Ames and Langley Research Centers, Boeing Airplane Company, McDonald Aircraft Company, Arnold Engineering Development Center, National Aerospace Laboratory of the Netherlands, National Research Council of Canada, and the Royal Aircraft Establishment of England. Some commercial sensors that may be applicable to accurate angle measurements were also reviewed. It was found that the optical sensor systems were based on interferometers, polarized light detector, linear or area photodiode cameras, position sensing photodetectors, and laser scanners. Several of the optical sensors can meet the requirements of the Ames Unitary Plan Wind Tunnel. Two of these, the Boeing interferometer and the Complere lateral effect photodiode sensors are being developed for the Ames Unitary Plan Wind Tunnel.

A coactive interdisciplinary research program with NASA

NASA Technical Reports Server (NTRS)

Rouse, J. W., Jr.

1972-01-01

The applications area of the Texas A&M University remote sensing program consists of a series of coactive projects with NASA/MSC personnel. In each case, the Remote Sensing Center has served to complement and enhance the research capability within the Manned Spacecraft Center. In addition to the applications study area, the Texas A&M University program includes coordinated projects in sensors and data analysis. Under the sensors area, an extensive experimental study of microwave radiometry for soil moisture determination established the effect of soil moisture on the measured brightness temperature for several different soil types. The data analysis area included a project which ERTS-A and Skylab data were simulated using aircraft multispectral scanner measurements at two altitudes. This effort resulted in development of a library of computer programs which provides an operational capability in classification analysis of multispectral data.

Development of n+-in-p large-area silicon microstrip sensors for very high radiation environments - ATLAS12 design and initial results

NASA Astrophysics Data System (ADS)

Unno, Y.; Edwards, S. O.; Pyatt, S.; Thomas, J. P.; Wilson, J. A.; Kierstead, J.; Lynn, D.; Carter, J. R.; Hommels, L. B. A.; Robinson, D.; Bloch, I.; Gregor, I. M.; Tackmann, K.; Betancourt, C.; Jakobs, K.; Kuehn, S.; Mori, R.; Parzefall, U.; Wiik-Fucks, L.; Clark, A.; Ferrere, D.; Gonzalez Sevilla, S.; Ashby, J.; Blue, A.; Bates, R.; Buttar, C.; Doherty, F.; Eklund, L.; McMullen, T.; McEwan, F.; O`Shea, V.; Kamada, S.; Yamamura, K.; Ikegami, Y.; Nakamura, K.; Takubo, Y.; Nishimura, R.; Takashima, R.; Chilingarov, A.; Fox, H.; Affolder, A. A.; Allport, P. P.; Casse, G.; Dervan, P.; Forshaw, D.; Greenall, A.; Wonsak, S.; Wormald, M.; Cindro, V.; Kramberger, G.; Mandic, I.; Mikuz, M.; Gorelov, I.; Hoeferkamp, M.; Palni, P.; Seidel, S.; Taylor, A.; Toms, K.; Wang, R.; Hessey, N. P.; Valencic, N.; Arai, Y.; Hanagaki, K.; Dolezal, Z.; Kodys, P.; Bohm, J.; Mikestikova, M.; Bevan, A.; Beck, G.; Ely, S.; Fadeyev, V.; Galloway, Z.; Grillo, A. A.; Martinez-McKinney, F.; Ngo, J.; Parker, C.; Sadrozinski, H. F.-W.; Schumacher, D.; Seiden, A.; French, R.; Hodgson, P.; Marin-Reyes, H.; Parker, K.; Paganis, S.; Jinnouchi, O.; Motohashi, K.; Todome, K.; Yamaguchi, D.; Hara, K.; Hagihara, M.; Garcia, C.; Jimenez, J.; Lacasta, C.; Marti i Garcia, S.; Soldevila, U.

2014-11-01

We have been developing a novel radiation-tolerant n+-in-p silicon microstrip sensor for very high radiation environments, aiming for application in the high luminosity large hadron collider. The sensors are fabricated in 6 in., p-type, float-zone wafers, where large-area strip sensor designs are laid out together with a number of miniature sensors. Radiation tolerance has been studied with ATLAS07 sensors and with independent structures. The ATLAS07 design was developed into new ATLAS12 designs. The ATLAS12A large-area sensor is made towards an axial strip sensor and the ATLAS12M towards a stereo strip sensor. New features to the ATLAS12 sensors are two dicing lines: standard edge space of 910 μm and slim edge space of 450 μm, a gated punch-through protection structure, and connection of orphan strips in a triangular corner of stereo strips. We report the design of the ATLAS12 layouts and initial measurements of the leakage current after dicing and the resistivity of the wafers.

Ultra-wideband radar sensors and networks

DOEpatents

Leach, Jr., Richard R; Nekoogar, Faranak; Haugen, Peter C

2013-08-06

Ultra wideband radar motion sensors strategically placed in an area of interest communicate with a wireless ad hoc network to provide remote area surveillance. Swept range impulse radar and a heart and respiration monitor combined with the motion sensor further improves discrimination.

Design and Development of a Mobile Sensor Based the Blind Assistance Wayfinding System

NASA Astrophysics Data System (ADS)

Barati, F.; Delavar, M. R.

2015-12-01

The blind and visually impaired people are facing a number of challenges in their daily life. One of the major challenges is finding their way both indoor and outdoor. For this reason, routing and navigation independently, especially in urban areas are important for the blind. Most of the blind undertake route finding and navigation with the help of a guide. In addition, other tools such as a cane, guide dog or electronic aids are used by the blind. However, in some cases these aids are not efficient enough in a wayfinding around obstacles and dangerous areas for the blind. As a result, the need to develop effective methods as decision support using a non-visual media is leading to improve quality of life for the blind through their increased mobility and independence. In this study, we designed and implemented an outdoor mobile sensor-based wayfinding system for the blind. The objectives of this study are to guide the blind for the obstacle recognition and the design and implementation of a wayfinding and navigation mobile sensor system for them. In this study an ultrasonic sensor is used to detect obstacles and GPS is employed for positioning and navigation in the wayfinding. This type of ultrasonic sensor measures the interval between sending waves and receiving the echo signals with respect to the speed of sound in the environment to estimate the distance to the obstacles. In this study the coordinates and characteristics of all the obstacles in the study area are already stored in a GIS database. All of these obstacles were labeled on the map. The ultrasonic sensor designed and constructed in this study has the ability to detect the obstacles in a distance of 2cm to 400cm. The implementation and the results obtained from the interview of a number of blind persons who employed the sensor verified that the designed mobile sensor system for wayfinding was very satisfactory.

End-user perspective of low-cost sensors for outdoor air pollution monitoring.

PubMed

Rai, Aakash C; Kumar, Prashant; Pilla, Francesco; Skouloudis, Andreas N; Di Sabatino, Silvana; Ratti, Carlo; Yasar, Ansar; Rickerby, David

2017-12-31

Low-cost sensor technology can potentially revolutionise the area of air pollution monitoring by providing high-density spatiotemporal pollution data. Such data can be utilised for supplementing traditional pollution monitoring, improving exposure estimates, and raising community awareness about air pollution. However, data quality remains a major concern that hinders the widespread adoption of low-cost sensor technology. Unreliable data may mislead unsuspecting users and potentially lead to alarming consequences such as reporting acceptable air pollutant levels when they are above the limits deemed safe for human health. This article provides scientific guidance to the end-users for effectively deploying low-cost sensors for monitoring air pollution and people's exposure, while ensuring reasonable data quality. We review the performance characteristics of several low-cost particle and gas monitoring sensors and provide recommendations to end-users for making proper sensor selection by summarizing the capabilities and limitations of such sensors. The challenges, best practices, and future outlook for effectively deploying low-cost sensors, and maintaining data quality are also discussed. For data quality assurance, a two-stage sensor calibration process is recommended, which includes laboratory calibration under controlled conditions by the manufacturer supplemented with routine calibration checks performed by the end-user under final deployment conditions. For large sensor networks where routine calibration checks are impractical, statistical techniques for data quality assurance should be utilised. Further advancements and adoption of sophisticated mathematical and statistical techniques for sensor calibration, fault detection, and data quality assurance can indeed help to realise the promised benefits of a low-cost air pollution sensor network. Copyright © 2017 Elsevier B.V. All rights reserved.

Advanced scanners and imaging systems for earth observations. [conferences

NASA Technical Reports Server (NTRS)

1973-01-01

Assessments of present and future sensors and sensor related technology are reported along with a description of user needs and applications. Five areas are outlined: (1) electromechanical scanners, (2) self-scanned solid state sensors, (3) electron beam imagers, (4) sensor related technology, and (5) user applications. Recommendations, charts, system designs, technical approaches, and bibliographies are included for each area.

Pheromone-based coordination strategy to static sensors on the ground and unmanned aerial vehicles carried sensors

NASA Astrophysics Data System (ADS)

Pignaton de Freitas, Edison; Heimfarth, Tales; Pereira, Carlos Eduardo; Morado Ferreira, Armando; Rech Wagner, Flávio; Larsson, Tony

2010-04-01

A current trend that is gaining strength in the wireless sensor network area is the use of heterogeneous sensor nodes in one coordinated overall network, needed to fulfill the requirements of sophisticated emerging applications, such as area surveillance systems. One of the main concerns when developing such sensor networks is how to provide coordination among the heterogeneous nodes, in order to enable them to efficiently respond the user needs. This study presents an investigation of strategies to coordinate a set of static sensor nodes on the ground cooperating with wirelessly connected Unmanned Aerial Vehicles (UAVs) carrying a variety of sensors, in order to provide efficient surveillance over an area of interest. The sensor nodes on the ground are set to issue alarms on the occurrence of a given event of interest, e.g. entrance of a non-authorized vehicle in the area, while the UAVs receive the issued alarms and have to decide which of them is the most suitable to handle the issued alarm. A bio-inspired coordination strategy based on the concept of pheromones is presented. As a complement of this strategy, a utility-based decision making approach is proposed.

Studies of uniformity of 50 μm low-gain avalanche detectors at the Fermilab test beam

NASA Astrophysics Data System (ADS)

Apresyan, A.; Xie, S.; Pena, C.; Arcidiacono, R.; Cartiglia, N.; Carulla, M.; Derylo, G.; Ferrero, M.; Flores, D.; Freeman, P.; Galloway, Z.; Ghassemi, A.; Al Ghoul, H.; Gray, L.; Hidalgo, S.; Kamada, S.; Los, S.; Mandurrino, M.; Merlos, A.; Minafra, N.; Pellegrini, G.; Quirion, D.; Ronzhin, A.; Royon, C.; Sadrozinski, H.; Seiden, A.; Sola, V.; Spiropulu, M.; Staiano, A.; Uplegger, L.; Yamamoto, K.; Yamamura, K.

2018-07-01

In this paper we report measurements of the uniformity of time resolution, signal amplitude, and charged particle detection efficiency across the sensor surface of low-gain avalanche detectors (LGAD). Comparisons of the performance of sensors with different doping concentrations and different active thicknesses are presented, as well as their temperature dependence and radiation tolerance up to 6 × 1014 n/cm2. Results were obtained at the Fermilab test beam facility using 120 GeV proton beams, and a high precision pixel tracking detector. LGAD sensors manufactured by the Centro Nacional de Microelectrónica (CNM) and Hamamatsu Photonics (HPK) were studied. The uniformity of the sensor response in pulse height before irradiation was found to have a 2% spread. The signal detection efficiency and timing resolution in the sensitive areas before irradiation were found to be 100% and 30-40 ps, respectively. A "no-response" area between pads was measured to be about 130 μm for CNM and 170 μm for HPK sensors. After a neutron fluence of 6 × 1014 n/cm2 the CNM sensor exhibits a large gain variation of up to a factor of 2.5 when comparing metalized and non-metalized sensor areas. An irradiated CNM sensor achieved a time resolution of 30 ps for the metalized area and 40 ps for the non-metalized area, while a HPK sensor irradiated to the same fluence achieved a 30 ps time resolution.

Large area thinned planar sensors for future high-luminosity-LHC upgrades

NASA Astrophysics Data System (ADS)

Wittig, T.; Lawerenz, A.; Röder, R.

2016-12-01

Planar hybrid silicon sensors are a well proven technology for past and current particle tracking detectors in HEP experiments. However, the future high-luminosity upgrades of the inner trackers at the LHC experiments pose big challenges to the detectors. A first challenge is an expected radiation damage level of up to 2ṡ 1016 neq/cm2. For planar sensors, one way to counteract the charge loss and thus increase the radiation hardness is to decrease the thickness of their active area. A second challenge is the large detector area which has to be built as cost-efficient as possible. The CiS research institute has accomplished a proof-of-principle run with n-in-p ATLAS-Pixel sensors in which a cavity is etched to the sensor's back side to reduce its thickness. One advantage of this technology is the fact that thick frames remain at the sensor edges and guarantee mechanical stability on wafer level while the sensor is left on the resulting thin membrane. For this cavity etching technique, no handling wafers are required which represents a benefit in terms of process effort and cost savings. The membranes with areas of up to ~ 4 × 4 cm2 and thicknesses of 100 and 150 μm feature a sufficiently good homogeneity across the whole wafer area. The processed pixel sensors show good electrical behaviour with an excellent yield for a suchlike prototype run. First sensors with electroless Ni- and Pt-UBM are already successfully assembled with read-out chips.

Tier-scalable reconnaissance: the challenge of sensor optimization, sensor deployment, sensor fusion, and sensor interoperability

NASA Astrophysics Data System (ADS)

Fink, Wolfgang; George, Thomas; Tarbell, Mark A.

2007-04-01

Robotic reconnaissance operations are called for in extreme environments, not only those such as space, including planetary atmospheres, surfaces, and subsurfaces, but also in potentially hazardous or inaccessible operational areas on Earth, such as mine fields, battlefield environments, enemy occupied territories, terrorist infiltrated environments, or areas that have been exposed to biochemical agents or radiation. Real time reconnaissance enables the identification and characterization of transient events. A fundamentally new mission concept for tier-scalable reconnaissance of operational areas, originated by Fink et al., is aimed at replacing the engineering and safety constrained mission designs of the past. The tier-scalable paradigm integrates multi-tier (orbit atmosphere surface/subsurface) and multi-agent (satellite UAV/blimp surface/subsurface sensing platforms) hierarchical mission architectures, introducing not only mission redundancy and safety, but also enabling and optimizing intelligent, less constrained, and distributed reconnaissance in real time. Given the mass, size, and power constraints faced by such a multi-platform approach, this is an ideal application scenario for a diverse set of MEMS sensors. To support such mission architectures, a high degree of operational autonomy is required. Essential elements of such operational autonomy are: (1) automatic mapping of an operational area from different vantage points (including vehicle health monitoring); (2) automatic feature extraction and target/region-of-interest identification within the mapped operational area; and (3) automatic target prioritization for close-up examination. These requirements imply the optimal deployment of MEMS sensors and sensor platforms, sensor fusion, and sensor interoperability.

Optical fiber sensors for materials and structures characterization

NASA Technical Reports Server (NTRS)

Lindner, D. K.; Claus, R. O.

1991-01-01

The final technical report on Optical Fiber Sensors for Materials and Structures Characterization, covering the period August 1990 through August 1991 is presented. Research programs in the following technical areas are described; sapphire optical fiber sensors; vibration analysis using two-mode elliptical core fibers and sensors; extrinsic Fabry-Perot interferometer development; and coatings for fluorescent-based sensor. Research progress in each of these areas was substantial, as evidenced by the technical publications which are included as appendices.

Tracking the harmonic response of magnetically-soft sensors for wireless temperature, stress, and corrosive monitoring.

PubMed

Ong, Keat G; Grimes, Craig A

2002-09-30

This paper describes the application of magnetically-soft ribbon-like sensors for measurement of temperature and stress, as well as corrosive monitoring, based upon changes in the amplitudes of the higher-order harmonics generated by the sensors in response to a magnetic interrogation signal. The sensors operate independently of mass loading, and so can be placed or rigidly embedded inside nonmetallic, opaque structures such as concrete or plastic. The passive harmonic-based sensor is remotely monitored through a single coplanar interrogation and detection coil. Effects due to the relative location of the sensor are eliminated by tracking harmonic amplitude ratios, thereby, enabling wide area monitoring. The wireless, passive, mass loading independent nature of the described sensor platform makes it ideally suited for long-term structural monitoring applications, such as measurement of temperature and stress inside concrete structures. A theoretical model is presented to explain the origin and behavior of the higher-order harmonics in response to temperature and stress. c2002 Elsevier Science B.V. All rights reserved.

Tracking the harmonic response of magnetically-soft sensors for wireless temperature, stress, and corrosive monitoring

NASA Technical Reports Server (NTRS)

Ong, Keat G.; Grimes, Craig A.

2002-01-01

This paper describes the application of magnetically-soft ribbon-like sensors for measurement of temperature and stress, as well as corrosive monitoring, based upon changes in the amplitudes of the higher-order harmonics generated by the sensors in response to a magnetic interrogation signal. The sensors operate independently of mass loading, and so can be placed or rigidly embedded inside nonmetallic, opaque structures such as concrete or plastic. The passive harmonic-based sensor is remotely monitored through a single coplanar interrogation and detection coil. Effects due to the relative location of the sensor are eliminated by tracking harmonic amplitude ratios, thereby, enabling wide area monitoring. The wireless, passive, mass loading independent nature of the described sensor platform makes it ideally suited for long-term structural monitoring applications, such as measurement of temperature and stress inside concrete structures. A theoretical model is presented to explain the origin and behavior of the higher-order harmonics in response to temperature and stress. c2002 Elsevier Science B.V. All rights reserved.

Easy-to-Fabricate and High-Sensitivity LSPR Type Specific Protein Detection Sensor Using AAO Nano-Pore Size Control

PubMed Central

Kim, Sae-Wan; Lee, Jae-Sung; Lee, Sang-Won; Kang, Byoung-Ho; Kwon, Jin-Beom; Kim, Ok-Sik; Kim, Ju-Seong; Kim, Eung-Soo; Kwon, Dae-Hyuk; Kang, Shin-Won

2017-01-01

In this study, we developed a pore size/pore area-controlled optical biosensor-based anodic aluminum oxide (AAO) nanostructure. As the pore size of AAO increases, the unit cell of AAO increases, which also increases the non-pore area to which the antibody binds. The increase in the number of antibodies immobilized on the surface of the AAO enables effective detection of trace amounts of antigen, because increased antigen-antibody bonding results in a larger surface refractive index change. High sensitivity was thus achieved through amplification of the interference wave of two vertically-incident reflected waves through the localized surface plasmon resonance phenomenon. The sensitivity of the fabricated sensor was evaluated by measuring the change in wavelength with the change in the refractive index of the device surface, and sensitivity was increased with increasing pore-size and non-pore area. The sensitivity of the fabricated sensor was improved and up to 11.8 ag/mL serum amyloid A1 antigen was detected. In addition, the selectivity of the fabricated sensor was confirmed through a reaction with a heterogeneous substance, C-reactive protein antigen. By using hard anodization during fabrication of the AAO, the fabrication time of the device was reduced and the AAO chip was fabricated quickly and easily. PMID:28406469

High-content analysis of single cells directly assembled on CMOS sensor based on color imaging.

PubMed

Tanaka, Tsuyoshi; Saeki, Tatsuya; Sunaga, Yoshihiko; Matsunaga, Tadashi

2010-12-15

A complementary metal oxide semiconductor (CMOS) image sensor was applied to high-content analysis of single cells which were assembled closely or directly onto the CMOS sensor surface. The direct assembling of cell groups on CMOS sensor surface allows large-field (6.66 mm×5.32 mm in entire active area of CMOS sensor) imaging within a second. Trypan blue-stained and non-stained cells in the same field area on the CMOS sensor were successfully distinguished as white- and blue-colored images under white LED light irradiation. Furthermore, the chemiluminescent signals of each cell were successfully visualized as blue-colored images on CMOS sensor only when HeLa cells were placed directly on the micro-lens array of the CMOS sensor. Our proposed approach will be a promising technique for real-time and high-content analysis of single cells in a large-field area based on color imaging. Copyright © 2010 Elsevier B.V. All rights reserved.

Expanding the Detection of Traversable Area with RealSense for the Visually Impaired

PubMed Central

Yang, Kailun; Wang, Kaiwei; Hu, Weijian; Bai, Jian

2016-01-01

The introduction of RGB-Depth (RGB-D) sensors into the visually impaired people (VIP)-assisting area has stirred great interest of many researchers. However, the detection range of RGB-D sensors is limited by narrow depth field angle and sparse depth map in the distance, which hampers broader and longer traversability awareness. This paper proposes an effective approach to expand the detection of traversable area based on a RGB-D sensor, the Intel RealSense R200, which is compatible with both indoor and outdoor environments. The depth image of RealSense is enhanced with IR image large-scale matching and RGB image-guided filtering. Traversable area is obtained with RANdom SAmple Consensus (RANSAC) segmentation and surface normal vector estimation, preliminarily. A seeded growing region algorithm, combining the depth image and RGB image, enlarges the preliminary traversable area greatly. This is critical not only for avoiding close obstacles, but also for allowing superior path planning on navigation. The proposed approach has been tested on a score of indoor and outdoor scenarios. Moreover, the approach has been integrated into an assistance system, which consists of a wearable prototype and an audio interface. Furthermore, the presented approach has been proved to be useful and reliable by a field test with eight visually impaired volunteers. PMID:27879634

A Radar-Enabled Collaborative Sensor Network Integrating COTS Technology for Surveillance and Tracking

PubMed Central

Kozma, Robert; Wang, Lan; Iftekharuddin, Khan; McCracken, Ernest; Khan, Muhammad; Islam, Khandakar; Bhurtel, Sushil R.; Demirer, R. Murat

2012-01-01

The feasibility of using Commercial Off-The-Shelf (COTS) sensor nodes is studied in a distributed network, aiming at dynamic surveillance and tracking of ground targets. Data acquisition by low-cost (<$50 US) miniature low-power radar through a wireless mote is described. We demonstrate the detection, ranging and velocity estimation, classification and tracking capabilities of the mini-radar, and compare results to simulations and manual measurements. Furthermore, we supplement the radar output with other sensor modalities, such as acoustic and vibration sensors. This method provides innovative solutions for detecting, identifying, and tracking vehicles and dismounts over a wide area in noisy conditions. This study presents a step towards distributed intelligent decision support and demonstrates effectiveness of small cheap sensors, which can complement advanced technologies in certain real-life scenarios. PMID:22438713

Chronology of Fabry-Perot Interferometer Fiber-Optic Sensors and Their Applications: A Review

PubMed Central

Islam, Md. Rajibul; Ali, Muhammad Mahmood; Lai, Man-Hong; Lim, Kok-Sing; Ahmad, Harith

2014-01-01

Optical fibers have been involved in the area of sensing applications for more than four decades. Moreover, interferometric optical fiber sensors have attracted broad interest for their prospective applications in sensing temperature, refractive index, strain measurement, pressure, acoustic wave, vibration, magnetic field, and voltage. During this time, numerous types of interferometers have been developed such as Fabry-Perot, Michelson, Mach-Zehnder, Sagnac Fiber, and Common-path interferometers. Fabry-Perot interferometer (FPI) fiber-optic sensors have been extensively investigated for their exceedingly effective, simple fabrication as well as low cost aspects. In this study, a wide variety of FPI sensors are reviewed in terms of fabrication methods, principle of operation and their sensing applications. The chronology of the development of FPI sensors and their implementation in various applications are discussed. PMID:24763250

Pseudo 2-transistor active pixel sensor using an n-well/gate-tied p-channel metal oxide semiconductor field eeffect transistor-type photodetector with built-in transfer gate

NASA Astrophysics Data System (ADS)

Seo, Sang-Ho; Seo, Min-Woong; Kong, Jae-Sung; Shin, Jang-Kyoo; Choi, Pyung

2008-11-01

In this paper, a pseudo 2-transistor active pixel sensor (APS) has been designed and fabricated by using an n-well/gate-tied p-channel metal oxide semiconductor field effect transistor (PMOSFET)-type photodetector with built-in transfer gate. The proposed sensor has been fabricated using a 0.35 μm 2-poly 4-metal standard complementary metal oxide semiconductor (CMOS) logic process. The pseudo 2-transistor APS consists of two NMOSFETs and one photodetector which can amplify the generated photocurrent. The area of the pseudo 2-transistor APS is 7.1 × 6.2 μm2. The sensitivity of the proposed pixel is 49 lux/(V·s). By using this pixel, a smaller pixel area and a higher level of sensitivity can be realized when compared with a conventional 3-transistor APS which uses a pn junction photodiode.

Numerical investigation of perforated polymer microcantilever sensor for contractile behavior of cardiomyocytes

NASA Astrophysics Data System (ADS)

Khoa Nguyen, Trieu; Lee, Dong-Weon; Lee, Bong-Kee

2017-06-01

In this study, a numerical investigation of microcantilever sensors for detecting the contractile behavior of cardiomyocytes (CMs) was performed. Recently, a novel surface-patterned perforated SU-8 microcantilever sensor has been developed for the preliminary screening of cardiac toxicity. From the contractile motion of the CMs cultured on the microcantilever surface, a macroscopic bending of the microcantilever was obtained, which is considered to reflect a physiological change. As a continuation of the previous research, a novel numerical method based on a surface traction model was proposed and verified to further understand the bending behavior of the microcantilevers. Effects of various factors, including surface traction magnitude, focal area of CMs, and stiffness of microcantilever, on the bending displacement were investigated. From static and transient analyses, the focal area was found to be the most crucial factor. In addition, the current result can provide a design guideline for various micromechanical devices based on the same principle.

Collaborative WiFi Fingerprinting Using Sensor-Based Navigation on Smartphones.

PubMed

Zhang, Peng; Zhao, Qile; Li, You; Niu, Xiaoji; Zhuang, Yuan; Liu, Jingnan

2015-07-20

This paper presents a method that trains the WiFi fingerprint database using sensor-based navigation solutions. Since micro-electromechanical systems (MEMS) sensors provide only a short-term accuracy but suffer from the accuracy degradation with time, we restrict the time length of available indoor navigation trajectories, and conduct post-processing to improve the sensor-based navigation solution. Different middle-term navigation trajectories that move in and out of an indoor area are combined to make up the database. Furthermore, we evaluate the effect of WiFi database shifts on WiFi fingerprinting using the database generated by the proposed method. Results show that the fingerprinting errors will not increase linearly according to database (DB) errors in smartphone-based WiFi fingerprinting applications.

Electrochemical sensing of bisphenol using a multilayer graphene nanobelt modified photolithography patterned platinum electrode

NASA Astrophysics Data System (ADS)

Karthick Kannan, Padmanathan; Hu, Chunxiao; Morgan, Hywel; Moshkalev, Stanislav A.; Sekhar Rout, Chandra

2016-09-01

An electrochemical sensor has been developed for the detection of Bisphenol-A (BPA) using photolithographically patterned platinum electrodes modified with multilayer graphene nanobelts (GNB). Compared to bare electrodes, the GNB modified electrode exhibited enhanced BPA oxidation current, due to the high effective surface area and high adsorption capacity of the GNB. The sensor showed a linear response over the concentration range from 0.5 μM-9 μM with a very low limit of detection = 37.33 nM. In addition, the sensor showed very good stability and reproducibility with good specificity, demonstrating that GNB is potentially a new material for the development of a practical BPA electrochemical sensor with application in both industrial and plastic industries.

Collaborative WiFi Fingerprinting Using Sensor-Based Navigation on Smartphones

PubMed Central

Zhang, Peng; Zhao, Qile; Li, You; Niu, Xiaoji; Zhuang, Yuan; Liu, Jingnan

2015-01-01

This paper presents a method that trains the WiFi fingerprint database using sensor-based navigation solutions. Since micro-electromechanical systems (MEMS) sensors provide only a short-term accuracy but suffer from the accuracy degradation with time, we restrict the time length of available indoor navigation trajectories, and conduct post-processing to improve the sensor-based navigation solution. Different middle-term navigation trajectories that move in and out of an indoor area are combined to make up the database. Furthermore, we evaluate the effect of WiFi database shifts on WiFi fingerprinting using the database generated by the proposed method. Results show that the fingerprinting errors will not increase linearly according to database (DB) errors in smartphone-based WiFi fingerprinting applications. PMID:26205269

On the use of RADARSAT-1 for monitoring malaria risk in Kenya

NASA Astrophysics Data System (ADS)

Ross, S. G.; Thomson, M. C.; Pultz, T.; Mbogo, C. M.; Regens, J. L.; Swalm, C.; Githure, J.; Yan, G.; Gu, W.; Beier, J. C.

2002-01-01

The incidence and spread of vector-borne infectious diseases are increasing concerns in many parts of the world. Earth obervation techniques provide a recognised means for monitoring and mapping disease risk as well as correlating environmental indicators with various disease vectors. Because the areas most impacted by vector-borne disease are remote and not easily monitored using traditional, labor intensive survey techniques, high spatial and temporal coverage provided by spaceborne sensors allows for the investigation of large areas in a timely manner. However, since the majority of infectious diseases occur in tropical areas, one of the main barriers to earth observation techniques is persistent cloud-cover. Synthetic Aperture Radar (SAR) technology offers a solution to this problem by providing all-weather, day and night imaging capability. Based on SAR's sensitivity to target moisture conditions, sensors such as RADARSAT-1 can be readily used to map wetland and swampy areas that are conducive to functioning as aquatic larval habitats. Irrigation patterns, deforestation practises and the effects of local flooding can be monitored using SAR imagery, and related to potential disease vector abundance and proximity to populated areas. This paper discusses the contribution of C-band radar remote sensing technology to monitoring and mapping malaria. Preliminary results using RADARSAT-1 for identifying areas of high mosquito (Anopheles gambiae s.l.) abundance along the Kenya coast will be discussed. The authors consider the potential of RADARSAT-1 data based on SAR sensor characteristics and the preliminary results obtained. Further potential of spaceborne SAR data for monitoring vector-borne disease is discussed with respect to future advanced SAR sensors such as RADARSAT-2.

Sensor-driven area coverage for an autonomous fixed-wing unmanned aerial vehicle.

PubMed

Paull, Liam; Thibault, Carl; Nagaty, Amr; Seto, Mae; Li, Howard

2014-09-01

Area coverage with an onboard sensor is an important task for an unmanned aerial vehicle (UAV) with many applications. Autonomous fixed-wing UAVs are more appropriate for larger scale area surveying since they can cover ground more quickly. However, their non-holonomic dynamics and susceptibility to disturbances make sensor coverage a challenging task. Most previous approaches to area coverage planning are offline and assume that the UAV can follow the planned trajectory exactly. In this paper, this restriction is removed as the aircraft maintains a coverage map based on its actual pose trajectory and makes control decisions based on that map. The aircraft is able to plan paths in situ based on sensor data and an accurate model of the on-board camera used for coverage. An information theoretic approach is used that selects desired headings that maximize the expected information gain over the coverage map. In addition, the branch entropy concept previously developed for autonomous underwater vehicles is extended to UAVs and ensures that the vehicle is able to achieve its global coverage mission. The coverage map over the workspace uses the projective camera model and compares the expected area of the target on the ground and the actual area covered on the ground by each pixel in the image. The camera is mounted on a two-axis gimbal and can either be stabilized or optimized for maximal coverage. Hardware-in-the-loop simulation results and real hardware implementation on a fixed-wing UAV show the effectiveness of the approach. By including the already developed automatic takeoff and landing capabilities, we now have a fully automated and robust platform for performing aerial imagery surveys.

A Magnetic Field Sensor Based on a Magnetic Fluid-Filled FP-FBG Structure

PubMed Central

Xia, Ji; Wang, Fuyin; Luo, Hong; Wang, Qi; Xiong, Shuidong

2016-01-01

Based on the characteristic magnetic-controlled refractive index property, in this paper, a magnetic fluid is used as a sensitive medium to detect the magnetic field in the fiber optic Fabry-Perot (FP) cavity. The temperature compensation in fiber Fabry-Perot magnetic sensor is demonstrated and achieved. The refractive index of the magnetic fluid varies with the applied magnetic field and external temperature, and a cross-sensitivity effect of the temperature and magnetic field occurs in the Fabry-Perot magnetic sensor and the accuracy of magnetic field measurements is affected by the thermal effect. In order to overcome this problem, we propose a modified sensor structure. With a fiber Bragg grating (FBG) written in the insert fiber end of the Fabry-Perot cavity, the FBG acts as a temperature compensation unit for the magnetic field measurement and it provides an effective solution to the cross-sensitivity effect. The experimental results show that the sensitivity of magnetic field detection improves from 0.23 nm/mT to 0.53 nm/mT, and the magnetic field measurement resolution finally reaches 37.7 T. The temperature-compensated FP-FBG magnetic sensor has obvious advantages of small volume and high sensitivity, and it has a good prospect in applications in the power industry and national defense technology areas. PMID:27136564

A Magnetic Field Sensor Based on a Magnetic Fluid-Filled FP-FBG Structure.

PubMed

Xia, Ji; Wang, Fuyin; Luo, Hong; Wang, Qi; Xiong, Shuidong

2016-04-29

Based on the characteristic magnetic-controlled refractive index property, in this paper, a magnetic fluid is used as a sensitive medium to detect the magnetic field in the fiber optic Fabry-Perot (FP) cavity. The temperature compensation in fiber Fabry-Perot magnetic sensor is demonstrated and achieved. The refractive index of the magnetic fluid varies with the applied magnetic field and external temperature, and a cross-sensitivity effect of the temperature and magnetic field occurs in the Fabry-Perot magnetic sensor and the accuracy of magnetic field measurements is affected by the thermal effect. In order to overcome this problem, we propose a modified sensor structure. With a fiber Bragg grating (FBG) written in the insert fiber end of the Fabry-Perot cavity, the FBG acts as a temperature compensation unit for the magnetic field measurement and it provides an effective solution to the cross-sensitivity effect. The experimental results show that the sensitivity of magnetic field detection improves from 0.23 nm/mT to 0.53 nm/mT, and the magnetic field measurement resolution finally reaches 37.7 T. The temperature-compensated FP-FBG magnetic sensor has obvious advantages of small volume and high sensitivity, and it has a good prospect in applications in the power industry and national defense technology areas.

Biomimetic MEMS sensor array for navigation and water detection

NASA Astrophysics Data System (ADS)

Futterknecht, Oliver; Macqueen, Mark O.; Karman, Salmah; Diah, S. Zaleha M.; Gebeshuber, Ille C.

2013-05-01

The focus of this study is biomimetic concept development for a MEMS sensor array for navigation and water detection. The MEMS sensor array is inspired by abstractions of the respective biological functions: polarized skylight-based navigation sensors in honeybees (Apis mellifera) and the ability of African elephants (Loxodonta africana) to detect water. The focus lies on how to navigate to and how to detect water sources in desert-like or remote areas. The goal is to develop a sensor that can provide both, navigation clues and help in detecting nearby water sources. We basically use the information provided by the natural polarization pattern produced by the sunbeams scattered within the atmosphere combined with the capability of the honeybee's compound eye to extrapolate the navigation information. The detection device uses light beam reactive MEMS, which are capable to detect the skylight polarization based on the Rayleigh sky model. For water detection we present various possible approaches to realize the sensor. In the first approach, polarization is used: moisture saturated areas near ground have a small but distinctively different effect on scattering and polarizing light than less moist ones. Modified skylight polarization sensors (Karman, Diah and Gebeshuber, 2012) are used to visualize this small change in scattering. The second approach is inspired by the ability of elephants to detect infrasound produced by underground water reservoirs, and shall be used to determine the location of underground rivers and visualize their exact routes.

Chemical Gas Sensors for Aeronautic and Space Applications 2

NASA Technical Reports Server (NTRS)

Hunter, Gary W.; Chen, Liong-Yu; Neudeck, Phil G.; Knight, Dale; Liu, C. C.; Wu, Q. H.; Zhou, H. J.; Makel, Darby; Liu, M.; Rauch, W. A.

1998-01-01

Aeronautic and space applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. Areas of interest include launch vehicle safety monitoring, emission monitoring, and fire detection. This paper discusses the needs of aeronautic and space applications and the point-contact sensor technology being developed to address these needs. The development of these sensors is based on progress in two types of technology: 1) Micromachining and microfabrication technology to fabricate miniaturized sensors. 2) The development of high temperature semiconductors, especially silicon carbide. Sensor development for each application involves its own challenges in the fields of materials science and fabrication technology. The number of dual-use commercial applications of this microfabricated gas sensor technology make this area of sensor development a field of significant interest.

Chemical Gas Sensors for Aeronautics and Space Applications III

NASA Technical Reports Server (NTRS)

Hunter, G. W.; Neudeck, P. G.; Chen, L. Y.; Liu, C. C.; Wu, Q. H.; Sawayda, M. S.; Jin, Z.; Hammond, J.; Makel, D.; Liu, M.;

Chemical Gas Sensors for Aeronautic and Space Applications 2

NASA Technical Reports Server (NTRS)

Hunter, G. W.; Chen, L. Y.; Neudeck, P. G.; Knight, D.; Liu, C. C.; Wu, Q. H.; Zhou, H. J.; Makel, D.; Liu, M.; Rauch, W. A.

1998-01-01

Aeronautic and Space applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. Areas of most interest include launch vehicle safety monitoring emission monitoring and fire detection. This paper discusses the needs of aeronautic and space applications and the point-contact sensor technology being developed to address these needs. The development of these sensor is based on progress two types of technology: 1) Micro-machining and micro-fabrication technology to fabricate miniaturized sensors. 2) The development of high temperature semiconductors, especially silicon carbide. Sensor development for each application involves its own challenges in the fields of materials science and fabrication technology. The number of dual-use commercial applications of this micro-fabricated gas sensor technology make this area of sensor development a field of significant interest.

CoR-MAC: Contention over Reservation MAC Protocol for Time-Critical Services in Wireless Body Area Sensor Networks

PubMed Central

Yu, Jeongseok; Park, Laihyuk; Park, Junho; Cho, Sungrae; Keum, Changsup

2016-01-01

Reserving time slots for urgent data, such as life-critical information, seems to be very attractive to guarantee their deadline requirements in wireless body area sensor networks (WBASNs). On the other hand, this reservation imposes a negative impact on performance for the utilization of a channel. This paper proposes a new channel access scheme referred to as the contention over reservation MAC (CoR-MAC) protocol for time-critical services in wireless body area sensor networks. CoR-MAC uses the dual reservation; if the reserved time slots are known to be vacant, other nodes can access the time slots by contention-based reservation to maximize the utilization of a channel and decrease the delay of the data. To measure the effectiveness of the proposed scheme against IEEE 802.15.4 and IEEE 802.15.6, we evaluated their performances with various performance indexes. The CoR-MAC showed 50% to 850% performance improvement in terms of the delay of urgent and time-critical data according to the number of nodes. PMID:27171085

A Dynamic Infrastructure for Interconnecting Disparate ISR/ISTAR Assets (the ITA Sensor Fabric)

DTIC Science & Technology

2009-07-01

areas of sensor identification, classification, interoperability and sensor data sharing, dissemination and consumability. This paper presents the ITA...sensors in the area of operations. This paper also presents a use case scenario developed in partnership with the U.S. Army Research Laboratory (ARL) and... paper we describe the Fabric, and its application to a simulated representative coalition operation scenario. The Fabric spans the network from the

Cooperative angle-only orbit initialization via fusion of admissible areas

NASA Astrophysics Data System (ADS)

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

2017-05-01

For the short-arc angle only orbit initialization problem, the admissible area is often used. However, the accuracy using a single sensor is often limited. For high value space objects, it is desired to achieve more accurate results. Fortunately, multiple sensors, which are dedicated to space situational awareness, are available. The work in this paper uses multiple sensors' information to cooperatively initialize the orbit based on the fusion of multiple admissible areas. Both the centralized fusion and decentralized fusion are discussed. Simulation results verify the expectation that the orbit initialization accuracy is improved by using information from multiple sensors.

Large-area graphene for sensor applications

NASA Astrophysics Data System (ADS)

Snow, Eric S.

2010-04-01

Graphene represents an important new material with potential Department of Defense sensor applications. At the Naval Research Laboratory we have developed three techniques to produce large-area graphene films. We have used this material to construct chemical and radio-frequency electromagnetic sensors. Here we report the initial results of this effort.

Multistage Security Mechanism For Hybrid, Large-Scale Wireless Sensor Networks

DTIC Science & Technology

2007-06-01

sensor network . Building on research in the areas of the wireless sensor networks (WSN) and the mobile ad hoc networks (MANET), this thesis proposes an...A wide area network consisting of ballistic missile defense satellites and terrestrial nodes can be viewed as a hybrid, large-scale mobile wireless

A Large Area Tactile Sensor Patch Based on Commercial Force Sensors

PubMed Central

Vidal-Verdú, Fernando; Barquero, Maria Jose; Castellanos-Ramos, Julián; Navas-González, Rafael; Sánchez, Jose Antonio; Serón, Javier; García-Cerezo, Alfonso

2011-01-01

This paper reports the design of a tactile sensor patch to cover large areas of robots and machines that interact with human beings. Many devices have been proposed to meet such a demand. These realizations are mostly custom-built or developed in the lab. The sensor of this paper is implemented with commercial force sensors. This has the benefit of a more foreseeable response of the sensor if its behavior is understood as the aggregation of readings from all the individual force sensors in the array. A few reported large area tactile sensors are also based on commercial sensors. However, the one in this paper is the first of this kind based on the use of polymeric commercial force sensing resistors (FSR) as unit elements of the array or tactels, which results in a robust sensor. The paper discusses design issues related to some necessary modifications of the force sensor, its assembly in an array, and the signal conditioning. The patch has 16 × 9 force sensors mounted on a flexible printed circuit board with a spatial resolution of 18.5 mm. The force range of a tactel is 6 N and its sensitivity is 0.6 V/N. The array is read at a rate of 78 frames per second. Finally, two simple application examples are also carried out with the sensor mounted on the forearm of a rescue robot that communicates with the sensor through a CAN bus. PMID:22163910

Is flat fielding safe for precision CCD astronomy?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baumer, Michael; Davis, Christopher P.; Roodman, Aaron

The ambitious goals of precision cosmology with wide-field optical surveys such as the Dark Energy Survey (DES) and the Large Synoptic Survey Telescope (LSST) demand precision CCD astronomy as their foundation. This in turn requires an understanding of previously uncharacterized sources of systematic error in CCD sensors, many of which manifest themselves as static effective variations in pixel area. Such variation renders a critical assumption behind the traditional procedure of flat fielding—that a sensor's pixels comprise a uniform grid—invalid. In this work, we present a method to infer a curl-free model of a sensor's underlying pixel grid from flat-field images,more » incorporating the superposition of all electrostatic sensor effects—both known and unknown—present in flat-field data. We use these pixel grid models to estimate the overall impact of sensor systematics on photometry, astrometry, and PSF shape measurements in a representative sensor from the Dark Energy Camera (DECam) and a prototype LSST sensor. Applying the method to DECam data recovers known significant sensor effects for which corrections are currently being developed within DES. For an LSST prototype CCD with pixel-response non-uniformity (PRNU) of 0.4%, we find the impact of "improper" flat fielding on these observables is negligible in nominal .7'' seeing conditions. Furthermore, these errors scale linearly with the PRNU, so for future LSST production sensors, which may have larger PRNU, our method provides a way to assess whether pixel-level calibration beyond flat fielding will be required.« less

Is flat fielding safe for precision CCD astronomy?

DOE PAGES

Baumer, Michael; Davis, Christopher P.; Roodman, Aaron

2017-07-06

The ambitious goals of precision cosmology with wide-field optical surveys such as the Dark Energy Survey (DES) and the Large Synoptic Survey Telescope (LSST) demand precision CCD astronomy as their foundation. This in turn requires an understanding of previously uncharacterized sources of systematic error in CCD sensors, many of which manifest themselves as static effective variations in pixel area. Such variation renders a critical assumption behind the traditional procedure of flat fielding—that a sensor's pixels comprise a uniform grid—invalid. In this work, we present a method to infer a curl-free model of a sensor's underlying pixel grid from flat-field images,more » incorporating the superposition of all electrostatic sensor effects—both known and unknown—present in flat-field data. We use these pixel grid models to estimate the overall impact of sensor systematics on photometry, astrometry, and PSF shape measurements in a representative sensor from the Dark Energy Camera (DECam) and a prototype LSST sensor. Applying the method to DECam data recovers known significant sensor effects for which corrections are currently being developed within DES. For an LSST prototype CCD with pixel-response non-uniformity (PRNU) of 0.4%, we find the impact of "improper" flat fielding on these observables is negligible in nominal .7'' seeing conditions. Furthermore, these errors scale linearly with the PRNU, so for future LSST production sensors, which may have larger PRNU, our method provides a way to assess whether pixel-level calibration beyond flat fielding will be required.« less

Theoretical analysis of microring resonator-based biosensor with high resolution and free of temperature influence

NASA Astrophysics Data System (ADS)

Jian, Aoqun; Zou, Lu; Tang, Haiquan; Duan, Qianqian; Ji, Jianlong; Zhang, Qianwu; Zhang, Xuming; Sang, Shengbo

2017-06-01

The issue of thermal effects is inevitable for the ultrahigh refractive index (RI) measurement. A biosensor with parallel-coupled dual-microring resonator configuration is proposed to achieve high resolution and free thermal effects measurement. Based on the coupled-resonator-induced transparency effect, the design and principle of the biosensor are introduced in detail, and the performance of the sensor is deduced by simulations. Compared to the biosensor based on a single-ring configuration, the designed biosensor has a 10-fold increased Q value according to the simulation results, thus the sensor is expected to achieve a particularly high resolution. In addition, the output signal of the mathematical model of the proposed sensor can eliminate the thermal influence by adopting an algorithm. This work is expected to have great application potentials in the areas of high-resolution RI measurement, such as biomedical discoveries, virus screening, and drinking water safety.

Wedge imaging spectrometer: application to drug and pollution law enforcement

NASA Astrophysics Data System (ADS)

Elerding, George T.; Thunen, John G.; Woody, Loren M.

1991-08-01

The Wedge Imaging Spectrometer (WIS) represents a novel implementation of an imaging spectrometer sensor that is compact and rugged and, therefore, suitable for use in drug interdiction and pollution monitoring activities. With performance characteristics equal to comparable conventional imaging spectrometers, it would be capable of detecting and identifying primary and secondary indicators of drug activities and pollution events. In the design, a linear wedge filter is mated to an area array of detectors to achieve two-dimensional sampling of the combined spatial/spectral information passed by the filter. As a result, the need for complex and delicate fore optics is avoided, and the size and weight of the instrument are approximately 50% that of comparable sensors. Spectral bandwidths can be controlled to provide relatively narrow individual bandwidths over a broad spectrum, including all visible and infrared wavelengths. This sensor concept has been under development at the Hughes Aircraft Co. Santa Barbara Research Center (SBRC), and hardware exists in the form of a brassboard prototype. This prototype provides 64 spectral bands over the visible and near infrared region (0.4 to 1.0 micrometers ). Implementation issues have been examined, and plans have been formulated for packaging the sensor into a test-bed aircraft for demonstration of capabilities. Two specific areas of utility to the drug interdiction problem are isolated: (1) detection and classification of narcotic crop growth areas and (2) identification of coca processing sites, cued by the results of broad-area survey and collateral information. Vegetation stress and change-detection processing may also be useful in detecting active from dormant airfields. For pollution monitoring, a WIS sensor could provide data with fine spectral and spatial resolution over suspect areas. On-board or ground processing of the data would isolate the presence of polluting effluents, effects on vegetation caused by airborne or other pollutants, or anomalous ground conditions indicative of buried or dumped toxic materials.

Induction of Inflammation In Vivo by Electrocardiogram Sensor Operation Using Wireless Power Transmission.

PubMed

Heo, Jin-Chul; Kim, Beomjoon; Kim, Yoon-Nyun; Kim, Dae-Kwang; Lee, Jong-Ha

2017-12-14

Prolonged monitoring by cardiac electrocardiogram (ECG) sensors is useful for patients with emergency heart conditions. However, implant monitoring systems are limited by lack of tissue biocompatibility. Here, we developed an implantable ECG sensor for real-time monitoring of ventricular fibrillation and evaluated its biocompatibility using an animal model. The implantable sensor comprised transplant sensors with two electrodes, a wireless power transmission system, and a monitoring system. The sensor was inserted into the subcutaneous tissue of the abdominal area and operated for 1 h/day for 5 days using a wireless power system. Importantly, the sensor was encapsulated by subcutaneous tissue and induced angiogenesis, inflammation, and phagocytosis. In addition, we observed that the levels of inflammation-related markers increased with wireless-powered transmission via the ECG sensor; in particular, levels of the Th-1 cytokine interleukin-12 were significantly increased. The results showed that induced tissue damage was associated with the use of wireless-powered sensors. We also investigated research strategies for the prevention of adverse effects caused by lack of tissue biocompatibility of a wireless-powered ECG monitoring system and provided information on the clinical applications of inflammatory reactions in implant treatment using the wireless-powered transmission system.

Induction of Inflammation In Vivo by Electrocardiogram Sensor Operation Using Wireless Power Transmission

PubMed Central

Heo, Jin-Chul; Kim, Beomjoon; Kim, Yoon-Nyun; Kim, Dae-Kwang; Lee, Jong-Ha

2017-01-01

Prolonged monitoring by cardiac electrocardiogram (ECG) sensors is useful for patients with emergency heart conditions. However, implant monitoring systems are limited by lack of tissue biocompatibility. Here, we developed an implantable ECG sensor for real-time monitoring of ventricular fibrillation and evaluated its biocompatibility using an animal model. The implantable sensor comprised transplant sensors with two electrodes, a wireless power transmission system, and a monitoring system. The sensor was inserted into the subcutaneous tissue of the abdominal area and operated for 1 h/day for 5 days using a wireless power system. Importantly, the sensor was encapsulated by subcutaneous tissue and induced angiogenesis, inflammation, and phagocytosis. In addition, we observed that the levels of inflammation-related markers increased with wireless-powered transmission via the ECG sensor; in particular, levels of the Th-1 cytokine interleukin-12 were significantly increased. The results showed that induced tissue damage was associated with the use of wireless-powered sensors. We also investigated research strategies for the prevention of adverse effects caused by lack of tissue biocompatibility of a wireless-powered ECG monitoring system and provided information on the clinical applications of inflammatory reactions in implant treatment using the wireless-powered transmission system. PMID:29240666

A Formal Approach to the Selection by Minimum Error and Pattern Method for Sensor Data Loss Reduction in Unstable Wireless Sensor Network Communications

PubMed Central

Kim, Changhwa; Shin, DongHyun

2017-01-01

There are wireless networks in which typically communications are unsafe. Most terrestrial wireless sensor networks belong to this category of networks. Another example of an unsafe communication network is an underwater acoustic sensor network (UWASN). In UWASNs in particular, communication failures occur frequently and the failure durations can range from seconds up to a few hours, days, or even weeks. These communication failures can cause data losses significant enough to seriously damage human life or property, depending on their application areas. In this paper, we propose a framework to reduce sensor data loss during communication failures and we present a formal approach to the Selection by Minimum Error and Pattern (SMEP) method that plays the most important role for the reduction in sensor data loss under the proposed framework. The SMEP method is compared with other methods to validate its effectiveness through experiments using real-field sensor data sets. Moreover, based on our experimental results and performance comparisons, the SMEP method has been validated to be better than others in terms of the average sensor data value error rate caused by sensor data loss. PMID:28498312

A Formal Approach to the Selection by Minimum Error and Pattern Method for Sensor Data Loss Reduction in Unstable Wireless Sensor Network Communications.

PubMed

Kim, Changhwa; Shin, DongHyun

2017-05-12

There are wireless networks in which typically communications are unsafe. Most terrestrial wireless sensor networks belong to this category of networks. Another example of an unsafe communication network is an underwater acoustic sensor network (UWASN). In UWASNs in particular, communication failures occur frequently and the failure durations can range from seconds up to a few hours, days, or even weeks. These communication failures can cause data losses significant enough to seriously damage human life or property, depending on their application areas. In this paper, we propose a framework to reduce sensor data loss during communication failures and we present a formal approach to the Selection by Minimum Error and Pattern (SMEP) method that plays the most important role for the reduction in sensor data loss under the proposed framework. The SMEP method is compared with other methods to validate its effectiveness through experiments using real-field sensor data sets. Moreover, based on our experimental results and performance comparisons, the SMEP method has been validated to be better than others in terms of the average sensor data value error rate caused by sensor data loss.

Nanosensors and nanomaterials for monitoring glucose in diabetes

PubMed Central

Cash, Kevin J.; Clark, Heather A.

2010-01-01

Worldwide, diabetes is a rapidly growing problem that is managed at the individual level by monitoring and controlling blood glucose levels to minimize the negative effects of the disease. Because of limitations in diagnostic methods, significant research efforts are focused on developing improved methods to measure glucose. Nanotechnology has impacted these efforts by increasing the surface area of sensors, improving the catalytic properties of electrodes and providing nanoscale sensors. Herein, we discuss developments in the past several years on both nanosensors that directly measure glucose as well as nanomaterials that improve glucose sensor function. Finally, we discuss challenges that must be overcome to apply these developments in the clinic. PMID:20869318

Investigation of substrate-mounted thin-film meteoroid sensors for use in large area impact experiments

NASA Technical Reports Server (NTRS)

Carollo, S. F.; Davis, J. M.; Dance, W. E.

1973-01-01

Two types of sensor designs were investigated: (1)a polysulfone dielectric film with vapor-deposited aluminum and gold sensor plates, bonded to a relatively thick aluminum substrate, and (2) an aluminum oxide (A1203) dielectric layer prepared on an aluminum substrate by anodization, with a layer of vapor-deposited aluminum providing one sensor plate and the substrate serving as the other plate. In the first design, specimens were prepared which indicate the state of the art for application of this type of sensor for elements of a meteoroid detection system having an area as large as 10 sq M. Techniques were investigated for casting large-area polysulfone films on the surface of water and for transferring the films from the water. Methods of preparing sensors by layering of films, the deposition of capacitor plates, and sensor film-to-substrate bonding, as well as techniques for making electrical connections to the capacitor plates, were studied.

Space telescope optical telescope assembly/scientific instruments. Phase B: Preliminary design and program definition study. Volume 2A(3): Astrometry

NASA Technical Reports Server (NTRS)

1976-01-01

Wide field measurements, namely, measurements of relative angular separations between stars over a relatively wide field for parallax and proper motion determinations, were made with the third fine guidance sensor. Narrow field measurements, i.e., double star measurements, are accomplished primarily with the area photometer or faint object camera at f/96. The wavelength range required can be met by the fine guidance sensor which has a spectral coverage from 3000 to 7500 A. The field of view of the fine guidance sensor also exceeds that required for the wide field astrometric instrument. Requirements require a filter wheel for the wide field astrometer, and so one was incorporated into the design of the fine guidance sensor. The filter wheel probably would contain two neutral density filters to extend the dynamic range of the sensor and three spectral filters for narrowing effective double star magnitude difference.

Traffic Adaptive Energy Efficient and Low Latency Medium Access Control for Wireless Sensor Networks

NASA Astrophysics Data System (ADS)

Yadav, Rajesh; Varma, Shirshu; Malaviya, N.

2008-05-01

Medium access control for wireless sensor networks has been a very active research area in the recent years. The traditional wireless medium access control protocol such as IEEE 802.11 is not suitable for the sensor network application because these are battery powered. The recharging of these sensor nodes is expensive and also not possible. The most of the literature in the medium access for the sensor network focuses on the energy efficiency. The proposed MAC protocol solves the energy inefficiency caused by idle listening, control packet overhead and overhearing taking nodes latency into consideration based on the network traffic. Simulation experiments have been performed to demonstrate the effectiveness of the proposed approach. The validation of the simulation results of the proposed MAC has been done by comparing it with the analytical model. This protocol has been simulated in Network Simulator ns-2.

Estimation and Fusion for Tracking Over Long-Haul Links Using Artificial Neural Networks

DOE PAGES

Liu, Qiang; Brigham, Katharine; Rao, Nageswara S. V.

2017-02-01

In a long-haul sensor network, sensors are remotely deployed over a large geographical area to perform certain tasks, such as tracking and/or monitoring of one or more dynamic targets. A remote fusion center fuses the information provided by these sensors so that a final estimate of certain target characteristics – such as the position – is expected to possess much improved quality. In this paper, we pursue learning-based approaches for estimation and fusion of target states in longhaul sensor networks. In particular, we consider learning based on various implementations of artificial neural networks (ANNs). Finally, the joint effect of (i)more » imperfect communication condition, namely, link-level loss and delay, and (ii) computation constraints, in the form of low-quality sensor estimates, on ANN-based estimation and fusion, is investigated by means of analytical and simulation studies.« less

Estimation and Fusion for Tracking Over Long-Haul Links Using Artificial Neural Networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Qiang; Brigham, Katharine; Rao, Nageswara S. V.

In a long-haul sensor network, sensors are remotely deployed over a large geographical area to perform certain tasks, such as tracking and/or monitoring of one or more dynamic targets. A remote fusion center fuses the information provided by these sensors so that a final estimate of certain target characteristics – such as the position – is expected to possess much improved quality. In this paper, we pursue learning-based approaches for estimation and fusion of target states in longhaul sensor networks. In particular, we consider learning based on various implementations of artificial neural networks (ANNs). Finally, the joint effect of (i)more » imperfect communication condition, namely, link-level loss and delay, and (ii) computation constraints, in the form of low-quality sensor estimates, on ANN-based estimation and fusion, is investigated by means of analytical and simulation studies.« less

Design, development and fabrication of a Solar Experiment Alignment Sensor (SEAS)

NASA Technical Reports Server (NTRS)

Bancroft, J. R.; Fain, M. Z.; Johnson, D. F.

1971-01-01

The design, development and testing of a laboratory SEAS (Solar Experiment Alignment Sensor) system are presented. The system is capable of overcoming traditional alignment and calibration problems to permit pointing anywhere on the solar disc to an accuracy of five arc seconds. The concept, development and laboratory testing phases of the program are discussed, and particular attention has been given to specific problems associated with selection of materials, and components. The conclusions summarize performance capability and discuss areas for further study including the effects of solar limb darkening and effects of annual variations in the apparent solar diameter.

Calibration of low-cost gas sensors for an urban air quality monitoring network

NASA Astrophysics Data System (ADS)

Scott, A.; Kelley, C.; He, C.; Ghugare, P.; Lehman, A.; Benish, S.; Stratton, P.; Dickerson, R. R.; Zuidema, C.; Azdoud, Y.; Ren, X.

2017-12-01

In a warming world, environmental pollution may be exacerbated by anthropogenic activities, such as climate change and the urban heat island effect, as well as natural phenomena such as heat waves. However, monitoring air pollution at federal reference standards (approximately 1 part per billion or ppb for ambient ozone) is cost-prohibitive in heterogeneous urban areas as many expensive devices are required to fully capture a region's geo-spatial variability. Innovation in low-cost sensors provide a potential solution, yet technical challenges remain to overcome possible imprecision in the data. We present the calibrations of ozone and nitrous dioxide from a low-cost air quality monitoring device designed for the Baltimore Open Air Project. The sensors used in this study are commercially available thin film electrochemical sensors from SPEC Sensor, which are amperometric, meaning they generate current proportional to volumetric fraction of gas. The results of sensor calibrations in the laboratory and field are presented.

A two-ply polymer-based flexible tactile sensor sheet using electric capacitance.

PubMed

Guo, Shijie; Shiraoka, Takahisa; Inada, Seisho; Mukai, Toshiharu

2014-01-29

Traditional capacitive tactile sensor sheets usually have a three-layered structure, with a dielectric layer sandwiched by two electrode layers. Each electrode layer has a number of parallel ribbon-like electrodes. The electrodes on the two electrode layers are oriented orthogonally and each crossing point of the two perpendicular electrode arrays makes up a capacitive sensor cell on the sheet. It is well known that compatibility between measuring precision and resolution is difficult, since decreasing the width of the electrodes is required to obtain a high resolution, however, this may lead to reduction of the area of the sensor cells, and as a result, lead to a low Signal/Noise (S/N) ratio. To overcome this problem, a new multilayered structure and related calculation procedure are proposed. This new structure stacks two or more sensor sheets with shifts in position. Both a high precision and a high resolution can be obtained by combining the signals of the stacked sensor sheets. Trial production was made and the effect was confirmed.

Large-Area All-Textile Pressure Sensors for Monitoring Human Motion and Physiological Signals.

PubMed

Liu, Mengmeng; Pu, Xiong; Jiang, Chunyan; Liu, Ting; Huang, Xin; Chen, Libo; Du, Chunhua; Sun, Jiangman; Hu, Weiguo; Wang, Zhong Lin

2017-11-01

Wearable pressure sensors, which can perceive and respond to environmental stimuli, are essential components of smart textiles. Here, large-area all-textile-based pressure-sensor arrays are successfully realized on common fabric substrates. The textile sensor unit achieves high sensitivity (14.4 kPa -1 ), low detection limit (2 Pa), fast response (≈24 ms), low power consumption (<6 µW), and mechanical stability under harsh deformations. Thanks to these merits, the textile sensor is demonstrated to be able to recognize finger movement, hand gestures, acoustic vibrations, and real-time pulse wave. Furthermore, large-area sensor arrays are successfully fabricated on one textile substrate to spatially map tactile stimuli and can be directly incorporated into a fabric garment for stylish designs without sacrifice of comfort, suggesting great potential in smart textiles or wearable electronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A heuristic for deriving the optimal number and placement of reconnaissance sensors

NASA Astrophysics Data System (ADS)

Nanda, S.; Weeks, J.; Archer, M.

2008-04-01

A key to mastering asymmetric warfare is the acquisition of accurate intelligence on adversaries and their assets in urban and open battlefields. To achieve this, one needs adequate numbers of tactical sensors placed in locations to optimize coverage, where optimality is realized by covering a given area of interest with the least number of sensors, or covering the largest possible subsection of an area of interest with a fixed set of sensors. Unfortunately, neither problem admits a polynomial time algorithm as a solution, and therefore, the placement of such sensors must utilize intelligent heuristics instead. In this paper, we present a scheme implemented on parallel SIMD processing architectures to yield significantly faster results, and that is highly scalable with respect to dynamic changes in the area of interest. Furthermore, the solution to the first problem immediately translates to serve as a solution to the latter if and when any sensors are rendered inoperable.

Design of In Situ Poled Ce(3+)-Doped Electrospun PVDF/Graphene Composite Nanofibers for Fabrication of Nanopressure Sensor and Ultrasensitive Acoustic Nanogenerator.

PubMed

Garain, Samiran; Jana, Santanu; Sinha, Tridib Kumar; Mandal, Dipankar

2016-02-01

We report an efficient, low-cost in situ poled fabrication strategy to construct a large area, highly sensitive, flexible pressure sensor by electrospun Ce(3+) doped PVDF/graphene composite nanofibers. The entire device fabrication process is scalable and enabling to large-area integration. It can able to detect imparting pressure as low as 2 Pa with high level of sensitivity. Furthermore, Ce(3+)-doped PVDF/graphene nanofiber based ultrasensitive pressure sensors can also be used as an effective nanogenerator as it generating an output voltage of 11 V with a current density ∼6 nA/cm(2) upon repetitive application of mechanical stress that could lit up 10 blue light emitting diodes (LEDs) instantaneously. Furthermore, to use it in environmental random vibrations (such as wind flow, water fall, transportation of vehicles, etc.), nanogenerator is integrated with musical vibration that exhibits to power up three blue LEDs instantly that promises as an ultrasensitive acoustic nanogenerator (ANG). The superior sensing properties in conjunction with mechanical flexibility, integrability, and robustness of nanofibers enabled real-time monitoring of sound waves as well as detection of different type of musical vibrations. Thus, ANG promises to use as an ultrasensitive pressure sensor, mechanical energy harvester, and effective power source for portable electronic and wearable devices.

Integration of IEEE 1451 and HL7 exchanging information for patients' sensor data.

PubMed

Kim, Wooshik; Lim, Suyoung; Ahn, Jinsoo; Nah, Jiyoung; Kim, Namhyun

2010-12-01

HL7 (Health Level 7) is a standard developed for exchanging incompatible healthcare information generated from programs or devices among heterogenous medical information systems. At present, HL7 is growing as a global standard. However, the HL7 standard does not support effective methods for treating data from various medical sensors, especially from mobile sensors. As ubiquitous systems are growing, HL7 must communicate with various medical transducers. In the area of sensor fields, IEEE 1451 is a group of standards for controlling transducers and for communicating data from/to various transducers. In this paper, we present the possibility of interoperability between the two standards, i.e., HL7 and IEEE 1451. After we present a method to integrate them and show the preliminary results of this approach.

Dual-core optical fiber based strain sensor for remote sensing in hard-to-reach areas

NASA Astrophysics Data System (ADS)

MÄ kowska, Anna; Szostkiewicz, Łukasz; Kołakowska, Agnieszka; Budnicki, Dawid; Bieńkowska, Beata; Ostrowski, Łukasz; Murawski, Michał; Napierała, Marek; Mergo, Paweł; Nasiłowski, Tomasz

2017-10-01

We present research on optical fiber sensors based on microstructured multi-core fiber. Elaborated sensor can be advantageously used in hard-to-reach areas by taking advantage of the fact, that optical fibers can play both the role of sensing elements and they can realize signal delivery. By using the sensor, it is possible to increase the level of the safety in the explosive endangered areas, e.g. in mine-like objects. As a base for the strain remote sensor we use dual-core fibers. The multi-core fibers possess a characteristic parameter called crosstalk, which is a measure of the amount of signal which can pass to the adjacent core. The strain-sensitive area is made by creating the tapered section, in which the level of crosstalk is changed. Due to this fact, we present broadened conception of fiber optic sensor designing. Strain measurement is realized thanks to the fact, that depending on the strain applied, the power distribution between the cores of dual-core fibers changes. Principle of operation allows realization of measurements both in wavelength and power domain.

50 CFR 218.170 - Specified activity and specified geographical area and effective dates.

Code of Federal Regulations, 2011 CFR

2011-10-01

... site QUTR site Test Vehicle Propulsion Thermal propulsion systemsElectric/Chemical propulsion systems..., classification and localization 05 4520 1510 Non-Navy testing 5 5 5 Acoustic & non-acoustic sensors (magnetic...

Robust snow avalanche detection using machine learning on infrasonic array data

NASA Astrophysics Data System (ADS)

Thüring, Thomas; Schoch, Marcel; van Herwijnen, Alec; Schweizer, Jürg

2014-05-01

Snow avalanches may threaten people and infrastructure in mountain areas. Automated detection of avalanche activity would be highly desirable, in particular during times of poor visibility, to improve hazard assessment, but also to monitor the effectiveness of avalanche control by explosives. In the past, a variety of remote sensing techniques and instruments for the automated detection of avalanche activity have been reported, which are based on radio waves (radar), seismic signals (geophone), optical signals (imaging sensor) or infrasonic signals (microphone). Optical imagery enables to assess avalanche activity with very high spatial resolution, however it is strongly weather dependent. Radar and geophone-based detection typically provide robust avalanche detection for all weather conditions, but are very limited in the size of the monitoring area. On the other hand, due to the long propagation distance of infrasound through air, the monitoring area of infrasonic sensors can cover a large territory using a single sensor (or an array). In addition, they are by far more cost effective than radars or optical imaging systems. Unfortunately, the reliability of infrasonic sensor systems has so far been rather low due to the strong variation of ambient noise (e.g. wind) causing a high false alarm rate. We analyzed the data collected by a low-cost infrasonic array system consisting of four sensors for the automated detection of avalanche activity at Lavin in the eastern Swiss Alps. A comparably large array aperture (~350m) allows highly accurate time delay estimations of signals which arrive at different times at the sensors, enabling precise source localization. An array of four sensors is sufficient for the time resolved source localization of signals in full 3D space, which is an excellent method to anticipate true avalanche activity. Robust avalanche detection is then achieved by using machine learning methods such as support vector machines. The system is initially trained by using characteristic data features from known avalanche and non-avalanche events. Data features are obtained from output signals of the source localization algorithm or from Fourier or time domain processing and support the learning phase of the system. A significantly improved detection rate as well as a reduction of the false alarm rate was achieved compared to previous approaches.

Subsurface material identification and sensor selection

NASA Astrophysics Data System (ADS)

T, H.; Reghunadh, R.; Ramesh, M. V.

2017-12-01

In India, most of the landslides occur during monsoon season and causes huge loss of life and property. Design of an early warning system for highly landslide prone area will reduce losses to a great extent. The in-situ monitoring systems needs deployment of several sensors inside a borehole for monitoring a particular slope. Amrita Center for Wireless Networks and Applications (AmritaWNA), Amrita University has designed, developed and deployed a Wireless Sensor Network (WSN) for real time landslide monitoring using geotechnical instruments and sensors like rain gauge, moisture sensor, piezometer, strain gauge, tilt meter and geophone inside a Deep Earth Probe (DEP) at different locations. These sensors provide point measurements of the subsurface at a higher accuracy. Every landslide prone terrain is unique with respect to its geology, hydrological conditions, meteorological conditions, velocity of movement etc. The decision of installing different geotechnical instruments in a landslide prone terrain is a crucial step to be considered. Rain gauge, moisture sensor, and piezometer are usually used in clay rich areas to sense the moisture and pore pressure values. Geophone and Crack meter are instruments used in rocky areas to monitor cracks and vibrations associated with a movement. Inclinometer and Strain gauge are usually placed inside a casing and can be used in both rocky and soil areas. In order to place geotechnical instruments and sensors at appropriate places Electrical Resistivity Tomography (ERT) method can be used. Variation in electrical resistivity values indicate the changes in composition, layer thickness, or contaminant levels. The derived true resistivity image can be used for identifying the type of materials present in the subsurface at different depths. We have used this method for identifying the type of materials present in our site at Chandmari (Sikkim). Fig 1 shows the typical resistivity values of a particular area in Chandmari site. The results shows that the area has more clay so the placement of moisture sensor and piezometer are required instead of placing geophone, crack meter etc.

A Polygon Model for Wireless Sensor Network Deployment with Directional Sensing Areas

PubMed Central

Wu, Chun-Hsien; Chung, Yeh-Ching

2009-01-01

The modeling of the sensing area of a sensor node is essential for the deployment algorithm of wireless sensor networks (WSNs). In this paper, a polygon model is proposed for the sensor node with directional sensing area. In addition, a WSN deployment algorithm is presented with topology control and scoring mechanisms to maintain network connectivity and improve sensing coverage rate. To evaluate the proposed polygon model and WSN deployment algorithm, a simulation is conducted. The simulation results show that the proposed polygon model outperforms the existed disk model and circular sector model in terms of the maximum sensing coverage rate. PMID:22303159

Design and Characterization of a Built-In CMOS TID Smart Sensor

NASA Astrophysics Data System (ADS)

Agustin, Javier; Gil, Carlos; Lopez-Vallejo, Marisa; Ituero, Pablo

2015-04-01

This paper describes a total ionization dose (TID) sensor that presents the following advantages: it is a digital sensor able to be integrated in CMOS circuits; it has a configurable sensitivity that allows radiation doses ranging from very low to high levels; its interface helps to integrate this design in a multidisciplinary sensor network; and it is self-timed, hence it does not need a clock signal. We designed, implemented and manufactured the sensor in a 0.35 μm CMOS commercial technology. It was irradiated with a 60Co source. This test was used to characterize the sensor in terms of the radiation response up to 575 krad. After irradiation, we monitored the sensor to control charge redistribution and annealing effects for 80 hours. We also exposed our design to meticulous temperature analysis from 0 to 50°C and we studied the acceleration on the annealing phenomena due to high temperatures. Sensor calibration takes into account the results of all tests. Finally we propose to use this sensor in a self-recovery system. The sensor manufactured in this work has an area of 0.047 mm 2, of which 22% is dedicated to measuring radiation. Its energy per conversion is 463 pJ.

Eraser-based eco-friendly fabrication of a skin-like large-area matrix of flexible carbon nanotube strain and pressure sensors

NASA Astrophysics Data System (ADS)

Sahatiya, Parikshit; Badhulika, Sushmee

2017-03-01

This paper reports a new type of electronic, recoverable skin-like pressure and strain sensor, produced on a flexible, biodegradable pencil-eraser substrate and fabricated using a solvent-free, low-cost and energy efficient process. Multi-walled carbon nanotube (MWCNT) film, the strain sensing element, was patterned on pencil eraser with a rolling pin and a pre-compaction mechanical press. This induces high interfacial bonding between the MWCNTs and the eraser substrate, which enables the sensor to achieve recoverability under ambient conditions. The eraser serves as a substrate for strain sensing, as well as acting as a dielectric for capacitive pressure sensing, thereby eliminating the dielectric deposition step, which is crucial in capacitive-based pressure sensors. The strain sensing transduction mechanism is attributed to the tunneling effect, caused by the elastic behavior of the MWCNTs and the strong mechanical interlock between MWCNTs and the eraser substrate, which restricts slippage of MWCNTs on the eraser thereby minimizing hysteresis. The gauge factor of the strain sensor was calculated to be 2.4, which is comparable to and even better than most of the strain and pressure sensors fabricated with more complex designs and architectures. The sensitivity of the capacitive pressure sensor was found to be 0.135 MPa-1.To demonstrate the applicability of the sensor as artificial electronic skin, the sensor was assembled on various parts of the human body and corresponding movements and touch sensation were monitored. The entire fabrication process is scalable and can be integrated into large areas to map spatial pressure distributions. This low-cost, easily scalable MWCNT pin-rolled eraser-based pressure and strain sensor has huge potential in applications such as artificial e-skin in flexible electronics and medical diagnostics, in particular in surgery as it provides high spatial resolution without a complex nanostructure architecture.

Eraser-based eco-friendly fabrication of a skin-like large-area matrix of flexible carbon nanotube strain and pressure sensors.

PubMed

Sahatiya, Parikshit; Badhulika, Sushmee

2017-03-03

This paper reports a new type of electronic, recoverable skin-like pressure and strain sensor, produced on a flexible, biodegradable pencil-eraser substrate and fabricated using a solvent-free, low-cost and energy efficient process. Multi-walled carbon nanotube (MWCNT) film, the strain sensing element, was patterned on pencil eraser with a rolling pin and a pre-compaction mechanical press. This induces high interfacial bonding between the MWCNTs and the eraser substrate, which enables the sensor to achieve recoverability under ambient conditions. The eraser serves as a substrate for strain sensing, as well as acting as a dielectric for capacitive pressure sensing, thereby eliminating the dielectric deposition step, which is crucial in capacitive-based pressure sensors. The strain sensing transduction mechanism is attributed to the tunneling effect, caused by the elastic behavior of the MWCNTs and the strong mechanical interlock between MWCNTs and the eraser substrate, which restricts slippage of MWCNTs on the eraser thereby minimizing hysteresis. The gauge factor of the strain sensor was calculated to be 2.4, which is comparable to and even better than most of the strain and pressure sensors fabricated with more complex designs and architectures. The sensitivity of the capacitive pressure sensor was found to be 0.135 MPa -1 .To demonstrate the applicability of the sensor as artificial electronic skin, the sensor was assembled on various parts of the human body and corresponding movements and touch sensation were monitored. The entire fabrication process is scalable and can be integrated into large areas to map spatial pressure distributions. This low-cost, easily scalable MWCNT pin-rolled eraser-based pressure and strain sensor has huge potential in applications such as artificial e-skin in flexible electronics and medical diagnostics, in particular in surgery as it provides high spatial resolution without a complex nanostructure architecture.

Radar Remote Sensing

NASA Technical Reports Server (NTRS)

Rosen, Paul A.

2012-01-01

This lecture was just a taste of radar remote sensing techniques and applications. Other important areas include Stereo radar grammetry. PolInSAR for volumetric structure mapping. Agricultural monitoring, soil moisture, ice-mapping, etc. The broad range of sensor types, frequencies of observation and availability of sensors have enabled radar sensors to make significant contributions in a wide area of earth and planetary remote sensing sciences. The range of applications, both qualitative and quantitative, continue to expand with each new generation of sensors.

Standards for efficient employment of wide-area motion imagery (WAMI) sensors

NASA Astrophysics Data System (ADS)

Randall, L. Scott; Maenner, Paul F.

2013-05-01

Airborne Wide Area Motion Imagery (WAMI) sensors provide the opportunity for continuous high-resolution surveillance of geographic areas covering tens of square kilometers. This is both a blessing and a curse. Data volumes from "gigapixel-class" WAMI sensors are orders of magnitude greater than for traditional "megapixel-class" video sensors. The amount of data greatly exceeds the capacities of downlinks to ground stations, and even if this were not true, the geographic coverage is too large for effective human monitoring. Although collected motion imagery is recorded on the platform, typically only small "windows" of the full field of view are transmitted to the ground; the full set of collected data can be retrieved from the recording device only after the mission has concluded. Thus, the WAMI environment presents several difficulties: (1) data is too massive for downlink; (2) human operator selection and control of the video windows may not be effective; (3) post-mission storage and dissemination may be limited by inefficient file formats; and (4) unique system implementation characteristics may thwart exploitation by available analysis tools. To address these issues, the National Geospatial-Intelligence Agency's Motion Imagery Standards Board (MISB) is developing relevant standard data exchange formats: (1) moving target indicator (MTI) and tracking metadata to support tipping and cueing of WAMI windows using "watch boxes" and "trip wires"; (2) control channel commands for positioning the windows within the full WAMI field of view; and (3) a full-field-of-view spatiotemporal tiled file format for efficient storage, retrieval, and dissemination. The authors previously provided an overview of this suite of standards. This paper describes the latest progress, with specific concentration on a detailed description of the spatiotemporal tiled file format.

Directly amplified redox sensor for on-chip chemical analysis

NASA Astrophysics Data System (ADS)

Takahashi, Sou; Futagawa, Masato; Ishida, Makoto; Sawada, Kazuaki

2014-03-01

In recent years, many groups have studied redox sensors for chemical analysis. A redox sensor has certain powerful advantages, such as its ability to detect multiple ions inside the sensing area, and its ability to measure concentrations of materials by using voltage and current signals. However, the output current signal of a redox sensor decreases when either concentration or sensing area decreases. Therefore, we propose the use of an amplified redox sensor (ARS) for measuring small current signals. The proposed sensor consists of a working electrode combined with a bipolar transistor. In this study, we fabricated an ARS sensor and performed low-concentration measurements using current signal amplification with an integrated bipolar transistor. The sensor chip successfully detected a potassium ferricyanide (K3[Fe(CN)6]) concentration of as low as 10 µM using cyclic voltammetry.

Development of wireless sensor network for landslide monitoring system

NASA Astrophysics Data System (ADS)

Suryadi; Puranto, Prabowo; Adinanta, Hendra; Tohari, Adrin; Priambodo, Purnomo S.

2017-05-01

A wireless sensor network has been developed to monitor soil movement of some observed areas periodically. The system consists of four nodes and one gateway which installed on a scope area of 0.2 Km2. Each of nodehastwo types of sensor,an inclinometer and an extensometer. An inclinometer sensor is used to measure the tilt of a structure while anextensometer sensor is used to measure the displacement of soil movement. Each of nodeisalso supported by awireless communication device, a solar power supply unit, and a microcontroller unit called sensor module. In this system, there is also gateway module as a main communication system consistinga wireless communication device, power supply unit, and rain gauge to measure the rainfall intensity of the observed area. Each sensor of inclinometer and extensometer isconnected to the sensor module in wiring system but sensor module iscommunicating with gateway in a wireless system. Those four nodes are alsoconnectedeach other in a wireless system collecting the data from inclinometer and extensometer sensors. Module Gateway istransmitting the instruction code to each sensor module one by one and collecting the data from them. Gateway module is an important part to communicate with not only sensor modules but also to the server. This wireless system wasdesigned toreducethe electric consumption powered by 80 WP solar panel and 55Ah battery. This system has been implemented in Pangalengan, Bandung, which has high intensity of rainfall and it can be seen on the website.

Pulse Based Time-of-Flight Range Sensing.

PubMed

Sarbolandi, Hamed; Plack, Markus; Kolb, Andreas

2018-05-23

Pulse-based Time-of-Flight (PB-ToF) cameras are an attractive alternative range imaging approach, compared to the widely commercialized Amplitude Modulated Continuous-Wave Time-of-Flight (AMCW-ToF) approach. This paper presents an in-depth evaluation of a PB-ToF camera prototype based on the Hamamatsu area sensor S11963-01CR. We evaluate different ToF-related effects, i.e., temperature drift, systematic error, depth inhomogeneity, multi-path effects, and motion artefacts. Furthermore, we evaluate the systematic error of the system in more detail, and introduce novel concepts to improve the quality of range measurements by modifying the mode of operation of the PB-ToF camera. Finally, we describe the means of measuring the gate response of the PB-ToF sensor and using this information for PB-ToF sensor simulation.

Sensor Fusion of Position- and Micro-Sensors (MEMS) integrated in a Wireless Sensor Network for movement detection in landslide areas

NASA Astrophysics Data System (ADS)

Arnhardt, Christian; Fernández-Steeger, Tomas; Azzam, Rafig

2010-05-01

Monitoring systems in landslide areas are important elements of effective Early Warning structures. Data acquisition and retrieval allows the detection of movement processes and thus is essential to generate warnings in time. Apart from the precise measurement, the reliability of data is fundamental, because outliers can trigger false alarms and leads to the loss of acceptance of such systems. For the monitoring of mass movements and their risk it is important to know, if there is movement, how fast it is and how trustworthy is the information. The joint project "Sensorbased landslide early warning system" (SLEWS) deals with these questions, and tries to improve data quality and to reduce false alarm rates, due to the combination of sensor date (sensor fusion). The project concentrates on the development of a prototypic Alarm- and Early Warning system (EWS) for different types of landslides by using various low-cost sensors, integrated in a wireless sensor network (WSN). The network consists of numerous connection points (nodes) that transfer data directly or over other nodes (Multi-Hop) in real-time to a data collection point (gateway). From there all the data packages are transmitted to a spatial data infrastructure (SDI) for further processing, analyzing and visualizing with respect to end-user specifications. The ad-hoc characteristic of the network allows the autonomous crosslinking of the nodes according to existing connections and communication strength. Due to the independent finding of new or more stable connections (self healing) a breakdown of the whole system is avoided. The bidirectional data stream enables the receiving of data from the network but also allows the transfer of commands and pointed requests into the WSN. For the detection of surface deformations in landslide areas small low-cost Micro-Electro-Mechanical-Systems (MEMS) and positionsensors from the automobile industries, different industrial applications and from other measurement technologies were chosen. The MEMS-Sensors are acceleration-, tilt- and barometric pressure sensors. The positionsensors are draw wire and linear displacement transducers. In first laboratory tests the accuracy and resolution were investigated. The tests showed good results for all sensors. For example tilt-movements can be monitored with an accuracy of +/- 0,06° and a resolution of 0,1°. With the displacement transducer change in length of >0,1mm is possible. Apart from laboratory tests, field tests in South France and Germany were done to prove data stability and movement detection under real conditions. The results obtained were very satisfying, too. In the next step the combination of numerous sensors (sensor fusion) of the same type (redundancy) or different types (complementary) was researched. Different experiments showed that there is a high concordance between identical sensor-types. According to different sensor parameters (sensitivity, accuracy, resolution) some sensor-types can identify changes earlier. Taking this into consideration, good correlations between different kinds of sensors were achieved, too. Thus the experiments showed that combination of sensors is possible and this could improve the detection of movement and movement rate but also outliers. Based on this results various algorithms were setup that include different statistical methods (outlier tests, testing of hypotheses) and procedures from decision theories (Hurwicz-criteria). These calculation formulas will be implemented in the spatial data infrastructure (SDI) for the further data processing and validation. In comparison with today existing mainly punctually working monitoring systems, the application of wireless sensor networks in combination with low-cost, but precise micro-sensors provides an inexpensive and easy to set up monitoring system also in large areas. The correlation of same but also different sensor-types permits a good data control. Thus the sensor fusion is a promising tool to detect movement more reliable and thus contributes essential to the improvement of Early Warning Systems.

Real-world evaluation of the effectiveness of reversing camera and parking sensor technologies in preventing backover pedestrian injuries.

PubMed

Keall, M D; Fildes, B; Newstead, S

2017-02-01

Backover injuries to pedestrians are a significant road safety issue, but their prevalence is underestimated as the majority of such injuries are often outside the scope of official road injury recording systems, which just focus on public roads. Based on experimental evidence, reversing cameras have been found to be effective in reducing the rate of collisions when reversing; the evidence for the effectiveness of reverse parking sensors has been mixed. The wide availability of these technologies in recent model vehicles provides impetus for real-world evaluations using crash data. A logistic model was fitted to data from crashes that occurred on public roads constituting 3172 pedestrian injuries in New Zealand and four Australian States to estimate the odds of backover injury (compared to other sorts of pedestrian injury crashes) for the different technology combinations fitted as standard equipment (both reversing cameras and sensors; just reversing cameras; just sensors; neither cameras nor sensors) controlling for vehicle type, jurisdiction, speed limit area and year of manufacture restricted to the range 2007-2013. Compared to vehicles without any of these technologies, reduced odds of backover injury were estimated for all three of these technology configurations: 0.59 (95% CI 0.39-0.88) for reversing cameras by themselves; 0.70 (95% CI 0.49-1.01) for both reversing cameras and sensors; 0.69 (95% CI 0.47-1.03) for reverse parking sensors by themselves. These findings are important as they are the first to our knowledge to present an assessment of real-world safety effectiveness of these technologies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Performance and analysis of MAC protocols based on application

NASA Astrophysics Data System (ADS)

Yadav, Ravi; Daniel, A. K.

2018-04-01

Wireless Sensor Network is one of the rapid emerging technology in recent decades. It covers large application area as civilian and military. Wireless Sensor Network primary consists of sensor nodes having low-power, low cost and multifunctional activities to collaborates and communicates via wireless medium. The deployment of sensor nodes are adhoc in nature, so sensor nodes are auto organize themselves in such a way to communicate with each other. The characteristics make more challenging areas on WSNs. This paper gives overview about characteristics of WSNs, Architecture and Contention Based MAC protocol. The paper present analysis of various protocol based on performance.

Nanoporous gold film based SPR sensors for trace chemical detection

NASA Astrophysics Data System (ADS)

Wang, Li; Gong, Xiaoqing; Wan, Xiumei; Lu, Dan-feng; Qi, Zhi-mei

2017-02-01

Thin films of nanoporous gold (NPG) have both localized and propagating surface plasmon resonance (SPR) effects. The propagating SPR effect of NPG film combined with its huge internal surface area makes it applicable as an evanescent wave sensor with high sensitivity. In this work, NPG films with controlled thicknesses were fabricated on glass substrates by sputtering deposition of AuAg films followed by dealloying in nitric acid. By using of the NPG films as the sensing layer, a broadband wavelength-interrogated SPR sensor was prepared for chemical and biological detection. The propagating SPR absorption band in the visible-near infrared region was clearly observed upon exposure of the NPG film to air, and this band was detected to move to longer wavelengths in response to adsorption of molecules within the NPG film. Simulations based on Fresnel equations combined with Bruggeman approximation were carried out for optimizing the propagating SPR property of NPG film. The sensor's performance was investigated using both bisphenol A (BPA) and lead (II) ions as analytes. According to the experimental results, the detection limits of the sensor are 5 nmol·L-1 for BPA and 1 nmol·L-1 for lead (II) ions. The work demonstrated the outstanding applicability of the NPG film based SPR sensor for sensitive environmental monitoring.

Semiconductor acceleration sensor

NASA Astrophysics Data System (ADS)

Ueyanagi, Katsumichi; Kobayashi, Mitsuo; Goto, Tomoaki

1996-09-01

This paper reports a practical semiconductor acceleration sensor especially suited for automotive air bag systems. The acceleration sensor includes four beams arranged in a swastika structure. Two piezoresistors are formed on each beam. These eight piezoresistors constitute a Wheatstone bridge. The swastika structure of the sensing elements, an upper glass plate and a lower glass plate exhibit the squeeze film effect which enhances air dumping, by which the constituent silicon is prevented from breakdown. The present acceleration sensor has the following features. The acceleration force component perpendicular to the sensing direction can be cancelled. The cross-axis sensitivity is less than 3 percent. And, the erroneous offset caused by the differences between the thermal expansion coefficients of the constituent materials can be canceled. The high aspect ratio configuration realized by plasma etching facilitates reducing the dimensions and improving the sensitivity of the acceleration sensor. The present acceleration sensor is 3.9 mm by 3.9 mm in area and 1.2 mm in thickness. The present acceleration sensor can measure from -50 to +50 G with sensitivity of 0.275 mV/G and with non-linearity of less than 1 percent. The acceleration sensor withstands shock of 3000 G.

Theoretical investigation on multilayer nanocomposite-based fiber optic SPR sensor

NASA Astrophysics Data System (ADS)

Shojaie, Ehsan; Madanipour, Khosro; Gharibzadeh, Azadeh; Abbasi, Shabnam

2017-06-01

In this work, a multilayer nanocomposite based fiber optic SPR sensor is considered and especially designed for CO2 gas detection. This proposed fiber sensor consists of fiber core, gold-silver alloy and the absorber layers. The investigation is based on the evaluation of the transmitted-power derived under the transfer matrix method and the multiple-reflection in the sensing area. In terms of sensitivity, the sensor performance is studied theoretically under various conditions related to the metal layer and its gold and silver nanoparticles to form a single alloy film. Effect of additional parameters such as the ratio of the alloy composition and the thickness of the alloy film on the performance of the SPR sensor is studied, as well. Finally, a four-layer structure is introduced to detect carbon dioxide gas. It contains core fiber, gold-silver alloy layer, an absorbent layer of carbon dioxide gas (KOH) and measurement environment. Lower price and size are the main advantages of using such a sensor in compare with commercial (NDIR) gas sensor. Theoretical results show by increasing the metal layer thickness the sensitivity of sensor is increased, and by increasing the ratio of the gold in alloy the sensitivity is decreased.

Zeolite-based Impedimetric Gas Sensor Device in Low-cost Technology for Hydrocarbon Gas Detection

PubMed Central

Reiß, Sebastian; Hagen, Gunter; Moos, Ralf

2008-01-01

Due to increasing environmental concerns the need for inexpensive selective gas sensors is increasing. This work deals with transferring a novel zeolite-based impedimetric hydrocarbon gas sensor principle, which has been originally manufactured in a costly combination of photolithography, thin-film processes, and thick-film processes to a low-cost technology comprising only thick-film processes and one electroplating step. The sensing effect is based on a thin chromium oxide layer between the interdigital electrodes and a Pt-loaded ZSM-5 zeolite film. When hydrocarbons are present in the sensor ambient, the electrical sensor impedance increases strongly and selectively. In the present work, the chromium oxide film is electroplated on Au screen-printed interdigital electrodes and then oxidized to Cr2O3. The electrode area is covered with the screen-printed zeolite. The sensor device is self-heated utilizing a planar platinum heater on the backside. The best sensor performance is obtained at a frequency of 3 Hz at around 350 °C. The good selectivity of the original sensor setup could be confirmed, but a strong cross-sensitivity to ammonia occurs, which might prohibit its original intention for use in automotive exhausts. PMID:27873966

A comprehensive survey of energy-aware routing protocols in wireless body area sensor networks.

PubMed

Effatparvar, Mehdi; Dehghan, Mehdi; Rahmani, Amir Masoud

2016-09-01

Wireless body area sensor network is a special purpose wireless sensor network that, employing wireless sensor nodes in, on, or around the human body, makes it possible to measure biological parameters of a person for specific applications. One of the most fundamental concerns in wireless body sensor networks is accurate routing in order to send data promptly and properly, and therefore overcome some of the challenges. Routing protocols for such networks are affected by a large number of factors including energy, topology, temperature, posture, the radio range of sensors, and appropriate quality of service in sensor nodes. Since energy is highly important in wireless body area sensor networks, and increasing the network lifetime results in benefiting greatly from sensor capabilities, improving routing performance with reduced energy consumption presents a major challenge. This paper aims to study wireless body area sensor networks and the related routing methods. It also presents a thorough, comprehensive review of routing methods in wireless body area sensor networks from the perspective of energy. Furthermore, different routing methods affecting the parameter of energy will be classified and compared according to their advantages and disadvantages. In this paper, fundamental concepts of wireless body area sensor networks are provided, and then the advantages and disadvantages of these networks are investigated. Since one of the most fundamental issues in wireless body sensor networks is to perform routing so as to transmit data precisely and promptly, we discuss the same issue. As a result, we propose a classification of the available relevant literature with respect to the key challenge of energy in the routing process. With this end in view, all important papers published between 2000 and 2015 are classified under eight categories including 'Mobility-Aware', 'Thermal-Aware', 'Restriction of Location and Number of Relays', 'Link-aware', 'Cluster- and Tree-Based', 'Cross-Layer', 'Opportunistic', and 'Medium Access Control'. We, then, provide a full description of the statistical analysis of each category in relation to all papers, current hybrid protocols, and the type of simulators used in each paper. Next, we analyze the distribution of papers in each category during various years. Moreover, for each category, the advantages and disadvantages as well as the number of issued papers in different years are given. We also analyze the type of layer and deployment of mathematical models or algorithmic techniques in each category. Finally, after introducing certain important protocols for each category, the goals, advantages, and disadvantages of the protocols are discussed and compared with each other.

Selenium nanomaterials: applications in electronics, catalysis and sensors.

PubMed

Chaudhary, Savita; Mehta, S K

2014-02-01

This review provides insights into the synthesis, functionalization, and applications of selenium nanoparticles in electronics, optics, catalysis and sensors. The variation of physicochemical properties such as particle size, surface area, and shape of the selenium nanoparticles and the effect of experimental conditions has also been discussed. An overview has also been provided on the fundamental electrical and optical properties of selenium nanomaterials as well as their utilization in different research fields. The work presents an insight on selenium nanoparticles with interesting properties and their future applications.

Flexible Multiplexed Surface Temperature Sensor

NASA Technical Reports Server (NTRS)

Daryabeigi, Kamran; Dillon-Townes, L. A.; Johnson, Preston B.; Ash, Robert L.

1995-01-01

Unitary array of sensors measures temperatures at points distributed over designated area on surface. Useful in measuring surface temperatures of aerodynamic models and thermally controlled objects. Made of combination of integrated-circuit microchips and film circuitry. Temperature-sensing chips scanned at speeds approaching 10 kHz. Operating range minus 40 degrees C to 120 degrees C. Flexibility of array conforms to curved surfaces. Multiplexer eliminates numerous monitoring cables. Control of acquisition and recording of data effected by connecting array to microcomputers via suitable interface circuitry.

Speedy routing recovery protocol for large failure tolerance in wireless sensor networks.

PubMed

Lee, Joa-Hyoung; Jung, In-Bum

2010-01-01

Wireless sensor networks are expected to play an increasingly important role in data collection in hazardous areas. However, the physical fragility of a sensor node makes reliable routing in hazardous areas a challenging problem. Because several sensor nodes in a hazardous area could be damaged simultaneously, the network should be able to recover routing after node failures over large areas. Many routing protocols take single-node failure recovery into account, but it is difficult for these protocols to recover the routing after large-scale failures. In this paper, we propose a routing protocol, referred to as ARF (Adaptive routing protocol for fast Recovery from large-scale Failure), to recover a network quickly after failures over large areas. ARF detects failures by counting the packet losses from parent nodes, and upon failure detection, it decreases the routing interval to notify the neighbor nodes of the failure. Our experimental results indicate that ARF could provide recovery from large-area failures quickly with less packets and energy consumption than previous protocols.

Radiation area monitor device and method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vencelj, Matjaz; Stowe, Ashley C.; Petrovic, Toni

A radiation area monitor device/method, utilizing: a radiation sensor; a rotating radiation shield disposed about the radiation sensor, wherein the rotating radiation shield defines one or more ports that are transparent to radiation; and a processor operable for analyzing and storing a radiation fingerprint acquired by the radiation sensor as the rotating radiation shield is rotated about the radiation sensor. Optionally, the radiation sensor includes a gamma and/or neutron radiation sensor. The device/method selectively operates in: a first supervised mode during which a baseline radiation fingerprint is acquired by the radiation sensor as the rotating radiation shield is rotated aboutmore » the radiation sensor; and a second unsupervised mode during which a subsequent radiation fingerprint is acquired by the radiation sensor as the rotating radiation shield is rotated about the radiation sensor, wherein the subsequent radiation fingerprint is compared to the baseline radiation fingerprint and, if a predetermined difference threshold is exceeded, an alert is issued.« less

Sensors for Entertainment.

PubMed

Lamberti, Fabrizio; Sanna, Andrea; Rokne, Jon

2016-07-15

Sensors are becoming ubiquitous in all areas of science, technology, and society. In this Special Issue on "Sensors for Entertainment", developments in progress and the current state of application scenarios for sensors in the field of entertainment is explored.

Research on sensor design for internet of things and laser manufacturing

NASA Astrophysics Data System (ADS)

Wang, Tao; Yao, Jianquan; Guo, Ling; Zhang, Yanchun

2010-12-01

In this paper, we will introduce the research on sensor design for IOT (Internet of Things) and laser manufacturing, and supporting the establishment of local area IOT. The main contents include studying on the structure designing of silicon micro tilt sensor, data acquisition and processing, addressing implanted and building Local Area IOT with wireless sensor network technology. At last, it is discussed the status and trends of the Internet of Things from the promoters, watchers, pessimists and doers.

Flexible quality of service model for wireless body area sensor networks.

PubMed

Liao, Yangzhe; Leeson, Mark S; Higgins, Matthew D

2016-03-01

Wireless body area sensor networks (WBASNs) are becoming an increasingly significant breakthrough technology for smart healthcare systems, enabling improved clinical decision-making in daily medical care. Recently, radio frequency ultra-wideband technology has developed substantially for physiological signal monitoring due to its advantages such as low-power consumption, high transmission data rate, and miniature antenna size. Applications of future ubiquitous healthcare systems offer the prospect of collecting human vital signs, early detection of abnormal medical conditions, real-time healthcare data transmission and remote telemedicine support. However, due to the technical constraints of sensor batteries, the supply of power is a major bottleneck for healthcare system design. Moreover, medium access control (MAC) needs to support reliable transmission links that allow sensors to transmit data safely and stably. In this Letter, the authors provide a flexible quality of service model for ad hoc networks that can support fast data transmission, adaptive schedule MAC control, and energy efficient ubiquitous WBASN networks. Results show that the proposed multi-hop communication ad hoc network model can balance information packet collisions and power consumption. Additionally, wireless communications link in WBASNs can effectively overcome multi-user interference and offer high transmission data rates for healthcare systems.

Sensing and Virtual Worlds - A Survey of Research Opportunities

NASA Technical Reports Server (NTRS)

Moore, Dana

2012-01-01

Virtual Worlds (VWs) have been used effectively in live and constructive military training. An area that remains fertile ground for exploration and a new vision involves integrating various traditional and now non-traditional sensors into virtual worlds. In this paper, we will assert that the benefits of this integration are several. First, we maintain that virtual worlds offer improved sensor deployment planning through improved visualization and stimulation of the model, using geo-specific terrain and structure. Secondly, we assert that VWs enhance the mission rehearsal process, and that using a mix of live avatars, non-player characters, and live sensor feeds (e.g. real time meteorology) can help visualization of the area of operations. Finally, tactical operations are improved via better collaboration and integration of real world sensing capabilities, and in most situations, 30 VWs improve the state of the art over current "dots on a map" 20 geospatial visualization. However, several capability gaps preclude a fuller realization of this vision. In this paper, we identify many of these gaps and suggest research directions

Integrated Joule switches for the control of current dynamics in parallel superconducting strips

NASA Astrophysics Data System (ADS)

Casaburi, A.; Heath, R. M.; Cristiano, R.; Ejrnaes, M.; Zen, N.; Ohkubo, M.; Hadfield, R. H.

2018-06-01

Understanding and harnessing the physics of the dynamic current distribution in parallel superconducting strips holds the key to creating next generation sensors for single molecule and single photon detection. Non-uniformity in the current distribution in parallel superconducting strips leads to low detection efficiency and unstable operation, preventing the scale up to large area sensors. Recent studies indicate that non-uniform current distributions occurring in parallel strips can be understood and modeled in the framework of the generalized London model. Here we build on this important physical insight, investigating an innovative design with integrated superconducting-to-resistive Joule switches to break the superconducting loops between the strips and thus control the current dynamics. Employing precision low temperature nano-optical techniques, we map the uniformity of the current distribution before- and after the resistive strip switching event, confirming the effectiveness of our design. These results provide important insights for the development of next generation large area superconducting strip-based sensors.

Optimizing Energy Consumption in Vehicular Sensor Networks by Clustering Using Fuzzy C-Means and Fuzzy Subtractive Algorithms

NASA Astrophysics Data System (ADS)

Ebrahimi, A.; Pahlavani, P.; Masoumi, Z.

2017-09-01

Traffic monitoring and managing in urban intelligent transportation systems (ITS) can be carried out based on vehicular sensor networks. In a vehicular sensor network, vehicles equipped with sensors such as GPS, can act as mobile sensors for sensing the urban traffic and sending the reports to a traffic monitoring center (TMC) for traffic estimation. The energy consumption by the sensor nodes is a main problem in the wireless sensor networks (WSNs); moreover, it is the most important feature in designing these networks. Clustering the sensor nodes is considered as an effective solution to reduce the energy consumption of WSNs. Each cluster should have a Cluster Head (CH), and a number of nodes located within its supervision area. The cluster heads are responsible for gathering and aggregating the information of clusters. Then, it transmits the information to the data collection center. Hence, the use of clustering decreases the volume of transmitting information, and, consequently, reduces the energy consumption of network. In this paper, Fuzzy C-Means (FCM) and Fuzzy Subtractive algorithms are employed to cluster sensors and investigate their performance on the energy consumption of sensors. It can be seen that the FCM algorithm and Fuzzy Subtractive have been reduced energy consumption of vehicle sensors up to 90.68% and 92.18%, respectively. Comparing the performance of the algorithms implies the 1.5 percent improvement in Fuzzy Subtractive algorithm in comparison.

FIRESTORM: a collaborative network suite application for rapid sensor data processing and precise decisive responses

NASA Astrophysics Data System (ADS)

Kaniyantethu, Shaji

2011-06-01

This paper discusses the many features and composed technologies in Firestorm™ - a Distributed Collaborative Fires and Effects software. Modern response management systems capitalize on the capabilities of a plethora of sensors and its output for situational awareness. Firestorm utilizes a unique networked lethality approach by integrating unmanned air and ground vehicles to provide target handoff and sharing of data between humans and sensors. The system employs Bayesian networks for track management of sensor data, and distributed auction algorithms for allocating targets and delivering the right effect without information overload to the Warfighter. Firestorm Networked Effects Component provides joint weapon-target pairing, attack guidance, target selection standards, and other fires and effects components. Moreover, the open and modular architecture allows for easy integration with new data sources. Versatility and adaptability of the application enable it to devise and dispense a suitable response to a wide variety of scenarios. Recently, this application was used for detecting and countering a vehicle intruder with the help of radio frequency spotter sensor, command driven cameras, remote weapon system, portable vehicle arresting barrier, and an unmanned aerial vehicle - which confirmed the presence of the intruder, as well as provided lethal/non-lethal response and battle damage assessment. The completed demonstrations have proved Firestorm's™ validity and feasibility to predict, detect, neutralize, and protect key assets and/or area against a variety of possible threats. The sensors and responding assets can be deployed with numerous configurations to cover the various terrain and environmental conditions, and can be integrated to a number of platforms.

Cu-modified carbon spheres/reduced graphene oxide as a high sensitivity of gas sensor for NO2 detection at room temperature

NASA Astrophysics Data System (ADS)

Su, Zhibin; Tan, Li; Yang, Ruiqiang; Zhang, Yu; Tao, Jin; Zhang, Nan; Wen, Fusheng

2018-03-01

Nitrogen dioxide (NO2) as one of the most serious air pollution is harmful to people's health, therefore high-performance gas sensors is critically needed. Here, Cu-modified carbon spheres/reduced graphene oxide (Cu@CS/RGO) composite have been prepared as NO2 gas sensor material. Carbon sphere in the interlayer of RGO can increase the specific surface area of RGO. Copper nanoparticles decorated on the surface of CS can effectively enhance the adsorption activity of RGO as supplier of free electrons. The experimental results showed that its particular structure improved the gas sensitivity of RGO at different NO2 concentrations at room temperature.

Nanosensors and nanomaterials for monitoring glucose in diabetes.

PubMed

Cash, Kevin J; Clark, Heather A

2010-12-01

Worldwide, diabetes is a rapidly growing problem that is managed at the individual level by monitoring and controlling blood glucose levels to minimize the negative effects of the disease. Because of limitations in diagnostic methods, significant research efforts are focused on developing improved methods to measure glucose. Nanotechnology has impacted these efforts by increasing the surface area of sensors, improving the catalytic properties of electrodes and providing nanoscale sensors. Here, we discuss developments in the past several years on both nanosensors that directly measure glucose and nanomaterials that improve glucose sensor function. Finally, we discuss challenges that must be overcome to apply these developments in the clinic. Copyright © 2010 Elsevier Ltd. All rights reserved.

Intelligent image processing for vegetation classification using multispectral LANDSAT data

NASA Astrophysics Data System (ADS)

Santos, Stewart R.; Flores, Jorge L.; Garcia-Torales, G.

2015-09-01

We propose an intelligent computational technique for analysis of vegetation imaging, which are acquired with multispectral scanner (MSS) sensor. This work focuses on intelligent and adaptive artificial neural network (ANN) methodologies that allow segmentation and classification of spectral remote sensing (RS) signatures, in order to obtain a high resolution map, in which we can delimit the wooded areas and quantify the amount of combustible materials present into these areas. This could provide important information to prevent fires and deforestation of wooded areas. The spectral RS input data, acquired by the MSS sensor, are considered in a random propagation remotely sensed scene with unknown statistics for each Thematic Mapper (TM) band. Performing high-resolution reconstruction and adding these spectral values with neighbor pixels information from each TM band, we can include contextual information into an ANN. The biggest challenge in conventional classifiers is how to reduce the number of components in the feature vector, while preserving the major information contained in the data, especially when the dimensionality of the feature space is high. Preliminary results show that the Adaptive Modified Neural Network method is a promising and effective spectral method for segmentation and classification in RS images acquired with MSS sensor.

Sensors for Entertainment

PubMed Central

Lamberti, Fabrizio; Sanna, Andrea; Rokne, Jon

2016-01-01

Sensors are becoming ubiquitous in all areas of science, technology, and society. In this Special Issue on “Sensors for Entertainment”, developments in progress and the current state of application scenarios for sensors in the field of entertainment is explored. PMID:27428981

Sensor Fusion and Smart Sensor in Sports and Biomedical Applications.

PubMed

Mendes, José Jair Alves; Vieira, Mário Elias Marinho; Pires, Marcelo Bissi; Stevan, Sergio Luiz

2016-09-23

The following work presents an overview of smart sensors and sensor fusion targeted at biomedical applications and sports areas. In this work, the integration of these areas is demonstrated, promoting a reflection about techniques and applications to collect, quantify and qualify some physical variables associated with the human body. These techniques are presented in various biomedical and sports applications, which cover areas related to diagnostics, rehabilitation, physical monitoring, and the development of performance in athletes, among others. Although some applications are described in only one of two fields of study (biomedicine and sports), it is very likely that the same application fits in both, with small peculiarities or adaptations. To illustrate the contemporaneity of applications, an analysis of specialized papers published in the last six years has been made. In this context, the main characteristic of this review is to present the largest quantity of relevant examples of sensor fusion and smart sensors focusing on their utilization and proposals, without deeply addressing one specific system or technique, to the detriment of the others.

Optimal Deployment of Sensor Nodes Based on Performance Surface of Underwater Acoustic Communication

PubMed Central

Choi, Jee Woong

2017-01-01

The underwater acoustic sensor network (UWASN) is a system that exchanges data between numerous sensor nodes deployed in the sea. The UWASN uses an underwater acoustic communication technique to exchange data. Therefore, it is important to design a robust system that will function even in severely fluctuating underwater communication conditions, along with variations in the ocean environment. In this paper, a new algorithm to find the optimal deployment positions of underwater sensor nodes is proposed. The algorithm uses the communication performance surface, which is a map showing the underwater acoustic communication performance of a targeted area. A virtual force-particle swarm optimization algorithm is then used as an optimization technique to find the optimal deployment positions of the sensor nodes, using the performance surface information to estimate the communication radii of the sensor nodes in each generation. The algorithm is evaluated by comparing simulation results between two different seasons (summer and winter) for an area located off the eastern coast of Korea as the selected targeted area. PMID:29053569

Fiber Optic Sensor Embedment Study for Multi-Parameter Strain Sensing

PubMed Central

Drissi-Habti, Monssef; Raman, Venkadesh; Khadour, Aghiad; Timorian, Safiullah

2017-01-01

The fiber optic sensors (FOSs) are commonly used for large-scale structure monitoring systems for their small size, noise free and low electrical risk characteristics. Embedded fiber optic sensors (FOSs) lead to micro-damage in composite structures. This damage generation threshold is based on the coating material of the FOSs and their diameter. In addition, embedded FOSs are aligned parallel to reinforcement fibers to avoid micro-damage creation. This linear positioning of distributed FOS fails to provide all strain parameters. We suggest novel sinusoidal sensor positioning to overcome this issue. This method tends to provide multi-parameter strains in a large surface area. The effectiveness of sinusoidal FOS positioning over linear FOS positioning is studied under both numerical and experimental methods. This study proves the advantages of the sinusoidal positioning method for FOS in composite material’s bonding. PMID:28333117

WO3 nanoparticle-based conformable pH sensor.

PubMed

Santos, Lídia; Neto, Joana P; Crespo, Ana; Nunes, Daniela; Costa, Nuno; Fonseca, Isabel M; Barquinha, Pedro; Pereira, Luís; Silva, Jorge; Martins, Rodrigo; Fortunato, Elvira

2014-08-13

pH is a vital physiological parameter that can be used for disease diagnosis and treatment as well as in monitoring other biological processes. Metal/metal oxide based pH sensors have several advantages regarding their reliability, miniaturization, and cost-effectiveness, which are critical characteristics for in vivo applications. In this work, WO3 nanoparticles were electrodeposited on flexible substrates over metal electrodes with a sensing area of 1 mm(2). These sensors show a sensitivity of -56.7 ± 1.3 mV/pH, in a wide pH range of 9 to 5. A proof of concept is also demonstrated using a flexible reference electrode in solid electrolyte with a curved surface. A good balance between the performance parameters (sensitivity), the production costs, and simplicity of the sensors was accomplished, as required for wearable biomedical devices.

Calculating the Areas of Polygons with a Smartphone Light Sensor

ERIC Educational Resources Information Center

Kapucu, Serkan; Simsek, Mertkan; Öçal, Mehmet Fatih

2017-01-01

This study explores finding the areas of polygons with a smartphone light sensor. A square and an irregular pentagon were chosen as our polygons. During the activity, the LED light was placed at the vertices of our polygons, and the illuminance values of this LED light were detected by the smartphone light sensor. The smartphone was placed on a…

A study to identify research issues in the area of electromagnetic measurements and signal handling of remotely sensed data

NASA Technical Reports Server (NTRS)

1982-01-01

Research issues in the area of electromagnetic measurements and signal handling of remotely sensed data are identified. The following seven issues are discussed; platform/sensor system position and velocity, platform/sensor attitudes and attitude rates, optics and antennas, detectors and associated electronics, sensor calibration, signal handling, and system design.

Staggered scheduling of sensor estimation and fusion for tracking over long-haul links

DOE PAGES

Liu, Qiang; Rao, Nageswara S. V.; Wang, Xin

2016-08-01

Networked sensing can be found in a multitude of real-world applications. Here, we focus on the communication-and computation-constrained long-haul sensor networks, where sensors are remotely deployed over a vast geographical area to perform certain tasks. Of special interest is a class of such networks where sensors take measurements of one or more dynamic targets and send their state estimates to a remote fusion center via long-haul satellite links. The severe loss and delay over such links can easily reduce the amount of sensor data received by the fusion center, thereby limiting the potential information fusion gain and resulting in suboptimalmore » tracking performance. In this paper, starting with the temporal-domain staggered estimation for an individual sensor, we explore the impact of the so-called intra-state prediction and retrodiction on estimation errors. We then investigate the effect of such estimation scheduling across different sensors on the spatial-domain fusion performance, where the sensing time epochs across sensors are scheduled in an asynchronous and staggered manner. In particular, the impact of communication delay and loss as well as sensor bias on such scheduling is explored by means of numerical and simulation studies that demonstrate the validity of our analysis.« less

600 C Logic Gates Using Silicon Carbide JFET's

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Beheim, Glenn M.; Salupo, Carl S.a

2000-01-01

Complex electronics and sensors are increasingly being relied on to enhance the capabilities and efficiency of modernjet aircraft. Some of these electronics and sensors monitor and control vital engine components and aerosurfaces that operate at high temperatures above 300 C. However, since today's silicon-based electronics technology cannot function at such high temperatures, these electronics must reside in environmentally controlled areas. This necessitates either the use of long wire runs between sheltered electronics and hot-area sensors and controls, or the fuel cooling of electronics and sensors located in high-temperature areas. Both of these low-temperature-electronics approaches suffer from serious drawbacks in terms of increased weight, decreased fuel efficiency, and reduction of aircraft reliability. A family of high-temperature electronics and sensors that could function in hot areas would enable substantial aircraft performance gains. Especially since, in the future, some turbine-engine electronics may need to function at temperatures as high as 600 C. This paper reports the fabrication and demonstration of the first semiconductor digital logic gates ever to function at 600 C. Key obstacles blocking the realization of useful 600 C turbine engine integrated sensor and control electronics are outlined.

Polymer Optical Fiber Sensor and the Prediction of Sensor Response Utilizing Artificial Neural Networks

NASA Astrophysics Data System (ADS)

Haroglu, Derya

The global market researches showed that there is a growing trend in the field of polymer optical fiber (POF) and POF sensors. Telecommunications, medicine, defense, aerospace, and automotive are the application areas of fiber optic sensors, where the automotive industry is the most promising application area for innovations in the field of POF sensors. The POF sensors in automobiles are particularly for detection of seat occupancy, and intelligent pedestrian protection systems. This dissertation investigates graded index perfluorinated polymer optical fiber as an intensity modulated intrinsic sensor for application in automotive seat occupancy sensing. Since a fiber optic sensor has a high bandwidth, is small in size, is lightweight, and is immune to electromagnetic interference (EMI) it offers higher performance than that of its electrical based counterparts such as strain gauge, elastomeric bladder, and resistive sensor systems. This makes the fiber optic sensor a potential suitable material for seat occupancy sensing. A textile-based fiber optic sensor was designed to be located in the area beneath the typical seated human's thighs. The pressure interval under which the proposed POF sensor design could perform well was found to be between 0.18 and 0.21 N/cm2, where perfluorinated (PF) graded index (GI) POF (62.5/750 mum) was used as the POF material. In addition, the effect of the automotive seat covering including face material (fabric) and foam backing to the sensor's performance was analyzed. The face fabric structure and the thickness of foam backing were not found to be significant factors to change the sensor results. A research study, survey, was conducted of which purpose was to better understand market demands in terms of sensor performance characteristics for automotive seat weight sensors, as a part of the Quality Function Deployment (QFD) House of Quality analysis. The companies joined the survey agreed on the first 5 most important sensor characteristics: reproducibility, accuracy, selectivity, aging, and resolution. Artificial neural network (ANN), a mathematical model formed by mimicking the human nervous system, was used to predict the sensor response. Qwiknet (version 2.23) software was used to develop ANNs and according to the results of Qwiknet the prediction performances for training and testing data sets were 75%, and 83.33% respectively. In this dissertation, Chapter 1 describes the worldwide plastic optical fiber (POF) and fiber optic sensor markets, and the existing textile structures used in fiber optic sensing design particularly for the applications of biomedical and structural health monitoring (SHM). Chapter 2 provides a literature review in detail on polymer optical fibers, fiber optic sensors, and occupancy sensing in the passenger seats of automobiles. Chapter 3 includes the research objectives. Chapter 4 presents the response of POF to tensile loading, bending, and cyclic tensile loading with discussion parts. Chapter 5 includes an e-mail based survey to prioritize customer needs in a Quality Function Deployment (QFD) format utilizing Analytic Hierarchy Process (AHP) and survey results. Chapter 6 describes the POF sensor design and the behavior of it under pressure. Chapter 7 provides a data analysis based on the experimental results of Chapter 6. Chapter 8 presents the summary of this study and recommendations for future work.

California's transition from conventional snowpack measurements to a developing remote sensing capability for water supply forecasting

NASA Technical Reports Server (NTRS)

Brown, A. J.; Peterson, N.

1980-01-01

California's Snow Survey Program and water supply forecasting procedures are described. A review is made of current activities and program direction on such matters as: the growing statewide network of automatic snow sensors; restrictions on the gathering hydrometeorological data in areas designated as wilderness; the use of satellite communications, which both provides a flexible network without mountaintop repeaters and satisfies the need for unobtrusiveness in wilderness areas; and the increasing operational use of snow covered area (SCA) obtained from satellite imagery, which, combined with water equivalent from snow sensors, provides a high correlation to the volumes and rates of snowmelt runoff. Also examined are the advantages of remote sensing; the anticipated effects of a new input of basin wide index of water equivalent, such as the obtained through microwave techniques, on future forecasting opportunities; and the future direction and goals of the California Snow Surveys Program.

Electronic sensor and actuator webs for large-area complex geometry cardiac mapping and therapy

PubMed Central

Kim, Dae-Hyeong; Ghaffari, Roozbeh; Lu, Nanshu; Wang, Shuodao; Lee, Stephen P.; Keum, Hohyun; D’Angelo, Robert; Klinker, Lauren; Su, Yewang; Lu, Chaofeng; Kim, Yun-Soung; Ameen, Abid; Li, Yuhang; Zhang, Yihui; de Graff, Bassel; Hsu, Yung-Yu; Liu, ZhuangJian; Ruskin, Jeremy; Xu, Lizhi; Lu, Chi; Omenetto, Fiorenzo G.; Huang, Yonggang; Mansour, Moussa; Slepian, Marvin J.; Rogers, John A.

2012-01-01

Curved surfaces, complex geometries, and time-dynamic deformations of the heart create challenges in establishing intimate, nonconstraining interfaces between cardiac structures and medical devices or surgical tools, particularly over large areas. We constructed large area designs for diagnostic and therapeutic stretchable sensor and actuator webs that conformally wrap the epicardium, establishing robust contact without sutures, mechanical fixtures, tapes, or surgical adhesives. These multifunctional web devices exploit open, mesh layouts and mount on thin, bio-resorbable sheets of silk to facilitate handling in a way that yields, after dissolution, exceptionally low mechanical moduli and thicknesses. In vivo studies in rabbit and pig animal models demonstrate the effectiveness of these device webs for measuring and spatially mapping temperature, electrophysiological signals, strain, and physical contact in sheet and balloon-based systems that also have the potential to deliver energy to perform localized tissue ablation. PMID:23150574

Dependable Wireless Sensor Networks for Prognostics and Health Management: A Survey

DTIC Science & Technology

2014-10-02

sensor network has many advantages. First of all, the absence of wires gives sensor networks the ability to cover a large scale surveillance area...system/component health state. Usually, this information is gathered through independent sensors or a wired network of sensors. The use of a wireless

A multi-sensor approach to assess erosion risk in low mountain range landscapes - a comparative case study in western Germany

NASA Astrophysics Data System (ADS)

Seeling, S.; Buddenbaum, H.; Seeger, M.; Löhnertz, M.

2009-04-01

In this presentation we summarize our experience in the derivation of variables for identification of erosion and areas endagered of erosion from different remote sensing sensors. The field study is situated at the "Zemmer-Plateau" (north-east from Trier) and was undertaken to compare the ability of different, passive and active, remote sensing sensors to derive several process parameters of soil erosion in agricultural landscapes. Additionally the added value of sensor combinations was investigated. Backscatter of C-Band microwave instruments is known to be sensitive to soil roughness and surface soil moisture. If landuse and roughness is approximately constant, backscatter is mostly affected by temporal changes in soil moisture. For the test site multitemporal imagery from the ASAR and ERS2 sensors was available. For the identification of areas prone to waterlogging an approach based on principal component analysis was used. Multitemporal imagery from optical sensors like Landsat and SPOT HRV allow the assessment of slow changes within the landscape and annual changes of vegetation cover. We used Landsat imagery from 1975, 1984 and 2000 to map the changes in landuse and associated soil development, multi temporal imagery from SPOT 4 and 5 satellites was used to identify different crop types. Additionally we investigated which areas that are prone to erosion by their topography position, have, due to maladjusted land management, not been protected by vegetation cover during the main annual rainfall season in 2003. Airborne Laser Scanning (ALS) data is well suited for discovering areas susceptible of erosion. Even under forest canopies ALS can provide high-resolution terrain models that can be used for identifying trenches, linear features, steep hills and other terrain features, which trigger erosion or are even results of erosion. ALS-derived DTMs usually have a spatial resolution of about 1 m, while DTMs from other data sources are much coarser. A key problem when working with ALS is finding the echoes that have really been reflected by the ground and not by buildings or vegetation. This is achieved by filtering the last and only return laser points. The investigations were aided be the analyses of two Quickbird datasets. The information layers derived from different sensors were merged into a preliminary erosion information system. This data base allows the identification of areas prone to erosion risk. Furthermore the results allow setting the focus on the most effective methods for further investigations.

Comparative Analysis of EO-1 ALI and Hyperion, and Landsat ETM+ Data for Mapping Forest Crown Closure and Leaf Area Index

PubMed Central

Pu, Ruiliang; Gong, Peng; Yu, Qian

2008-01-01

In this study, a comparative analysis of capabilities of three sensors for mapping forest crown closure (CC) and leaf area index (LAI) was conducted. The three sensors are Hyperspectral Imager (Hyperion) and Advanced Land Imager (ALI) onboard EO-1 satellite and Landsat-7 Enhanced Thematic Mapper Plus (ETM+). A total of 38 mixed coniferous forest CC and 38 LAI measurements were collected at Blodgett Forest Research Station, University of California at Berkeley, USA. The analysis method consists of (1) extracting spectral vegetation indices (VIs), spectral texture information and maximum noise fractions (MNFs), (2) establishing multivariate prediction models, (3) predicting and mapping pixel-based CC and LAI values, and (4) validating the mapped CC and LAI results with field validated photo-interpreted CC and LAI values. The experimental results indicate that the Hyperion data are the most effective for mapping forest CC and LAI (CC mapped accuracy (MA) = 76.0%, LAI MA = 74.7%), followed by ALI data (CC MA = 74.5%, LAI MA = 70.7%), with ETM+ data results being least effective (CC MA = 71.1%, LAI MA = 63.4%). This analysis demonstrates that the Hyperion sensor outperforms the other two sensors: ALI and ETM+. This is because of its high spectral resolution with rich subtle spectral information, of its short-wave infrared data for constructing optimal VIs that are slightly affected by the atmosphere, and of its more available MNFs than the other two sensors to be selected for establishing prediction models. Compared to ETM+ data, ALI data are better for mapping forest CC and LAI due to ALI data with more bands and higher signal-to-noise ratios than those of ETM+ data. PMID:27879906

Comparative Analysis of EO-1 ALI and Hyperion, and Landsat ETM+ Data for Mapping Forest Crown Closure and Leaf Area Index.

PubMed

Pu, Ruiliang; Gong, Peng; Yu, Qian

2008-06-06

In this study, a comparative analysis of capabilities of three sensors for mapping forest crown closure (CC) and leaf area index (LAI) was conducted. The three sensors are Hyperspectral Imager (Hyperion) and Advanced Land Imager (ALI) onboard EO-1 satellite and Landsat-7 Enhanced Thematic Mapper Plus (ETM+). A total of 38 mixed coniferous forest CC and 38 LAI measurements were collected at Blodgett Forest Research Station, University of California at Berkeley, USA. The analysis method consists of (1) extracting spectral vegetation indices (VIs), spectral texture information and maximum noise fractions (MNFs), (2) establishing multivariate prediction models, (3) predicting and mapping pixel-based CC and LAI values, and (4) validating the mapped CC and LAI results with field validated photo-interpreted CC and LAI values. The experimental results indicate that the Hyperion data are the most effective for mapping forest CC and LAI (CC mapped accuracy (MA) = 76.0%, LAI MA = 74.7%), followed by ALI data (CC MA = 74.5%, LAI MA = 70.7%), with ETM+ data results being least effective (CC MA = 71.1%, LAI MA = 63.4%). This analysis demonstrates that the Hyperion sensor outperforms the other two sensors: ALI and ETM+. This is because of its high spectral resolution with rich subtle spectral information, of its short-wave infrared data for constructing optimal VIs that are slightly affected by the atmosphere, and of its more available MNFs than the other two sensors to be selected for establishing prediction models. Compared to ETM+ data, ALI data are better for mapping forest CC and LAI due to ALI data with more bands and higher signal-to-noise ratios than those of ETM+ data.

Evaluation of cost-effective sol-gel-based sensor for monitoring of formaldehyde in workplace environment and cancer risk assessment.

PubMed

Bunkoed, Opas; Thavarungkul, Panote; Thammakhet, Chongdee; Kanatharana, Proespichaya

2013-01-01

Formaldehyde was monitored in the workplace environment of an adhesive manufacturer producing formaldehyde and urea-formaldehyde resin using a cost-effective sol-gel-based sensor. The sensor was first evaluated by comparing its performance to the conventional 2,4-dinitrophynylhydrazine-devivatization method (2,4-DNPH) followed by high-performance liquid chromatography coupled to a UV detector. The formaldehyde concentrations obtained by both techniques were not significantly different. The cost-effective sol-gel-based sensor was then used for monitoring formaldehyde levels in the laboratories, production areas and storage room. Formaldehyde concentrations in this adhesive manufacturer workplace environment were lower than the limit value of, 0.75 ppm for an 8-h time weight average and 2 ppm for a short-term exposure (15 min). However, the cancer risk for employees who worked in the laboratories, (1.7±0.7)×10(-4)-(5±2)×10(-4), were higher than the acceptable cancer risk recommended by the US EPA (10(-6)). Therefore, some precaution should be taken to reduce the risk, such as an increase of ventilation to dilute the levels of formaldehyde and use air cleaners to remove formaldehyde.

Directed Diffusion Modelling for Tesso Nilo National Parks Case Study

NASA Astrophysics Data System (ADS)

Yasri, Indra; Safrianti, Ery

2018-01-01

— Directed Diffusion (DD has ability to achieve energy efficiency in Wireless Sensor Network (WSN). This paper proposes Directed Diffusion (DD) modelling for Tesso Nilo National Parks (TNNP) case study. There are 4 stages of scenarios involved in this modelling. It’s started by appointing of sampling area through GPS coordinate. The sampling area is determined by optimization processes from 500m x 500m up to 1000m x 1000m with 100m increment in between. The next stage is sensor node placement. Sensor node is distributed in sampling area with three different quantities i.e. 20 nodes, 30 nodes and 40 nodes. One of those quantities is choose as an optimized sensor node placement. The third stage is to implement all scenarios in stages 1 and stages 2 on DD modelling. In the last stage, the evaluation process to achieve most energy efficient in the combination of optimized sampling area and optimized sensor node placement on Direct Diffusion (DD) routing protocol. The result shows combination between sampling area 500m x 500m and 20 nodes able to achieve energy efficient to support a forest preventive fire system at Tesso Nilo National Parks.

High-sensitive nitrogen dioxide and ethanol gas sensor using a reduced graphene oxide-loaded double split ring resonator

NASA Astrophysics Data System (ADS)

Singh, Sandeep Kumar; Azad, Prakrati; Akhtar, M. J.; Kar, Kamal K.

2017-08-01

A reduced graphene oxide (rGO) incorporated double split ring resonator (DSRR) portable microwave gas sensor is proposed in this work. The sensor is fabricated using two major steps: the DSRR is fabricated on the FR-4 substrate, which is excited by a high impedance microstrip line. The rGO is synthesized via a chemical route and coated inside the smaller ring of the DSRR. The SEM micrographs reveal crumpled sheets of rGO that provide a large surface area, and the XRD patterns of the as-synthesized rGO reveal the two-dimensional structure of the rGO nanosheets. The sensor performance is measured at room temperature using 100-400 ppm of ethanol and NO2 target gases. At 400 ppm, the sensor reveals a shift of 420 and 390 MHz in the S 21 frequency for NO2 and ethanol gases, respectively. The frequency shifts of 130 and 120 MHz in the S 21 resonance frequency are obtained for NO2 and ethanol gases, respectively, at a very low concentration of 100 ppm. The high sensitivity of the proposed rGO gas sensor is achieved due to the combined effect of the large surface area of the rGO responsible for accommodating more gas molecules, and its increased conductivity due to the transfer of the electron from the rGO. Moreover, an exceedingly short response time is observed for NO2 in comparison to ethanol, which allows the proposed sensor to be used for the selective detection of NO2 in a harsh environment. The overall approach used in this study is quite simple, and has great potential to enhance the gas detection behaviour of rGO.

An Investigation of New Snow Water Equivalence Sensing Modalities

NASA Astrophysics Data System (ADS)

Frolik, J.; Skalka, C.; Wemple, B.

2008-12-01

It is well known that snowpack is highly variable and influenced by a range of factors, including topography and vegetation cover. As such, single point measurements may be viewed as being inadequate to characterize snowpack in a given area. Thus motivated by the desire for distributed sensing, this work presents results of a proof-of-concept investigation for new, low-cost, snow water equivalence (SWE) sensors based on the attenuation of microwave and gamma radiation. First, our work considers the attenuation of microwave signals at 2.4 GHz and 5 GHz due to an accumulating snowpack. These frequencies coincide with those used for common wireless networks and thus our proposed sensor can leverage existing hardware designs which are low-cost and power efficient. Second, we present attenuation data for radiation energy occurring between 500 keV and 1 MeV. These results were obtained utilizing a radiation detector based on Cadmium Zinc Telluride (CZT) technology. The proposed sensor will leverage recent investments such CZT based designs for homeland security applications. We contend that sensors based on these modalities will be low-cost and low-energy and thus readily integrated with wireless sensor network hardware for distributed monitoring. In addition, these sensors will be compact and thus can be placed in locations not feasible for current SWE sensor designs (e.g., snow pillows) or in locations too dangerous for snow course measurements (e.g., areas prone to avalanche). Since neither sensing methods requires contact with the snowpack, these modalities are also immune to snow bridging effects which plague existing designs. We also present preliminary findings of work conducted in a mountainous forested setting in northern New England which examines the influence of forest vegetation on snowpack.

An advanced wide area chemical sensor testbed

NASA Astrophysics Data System (ADS)

Seeley, Juliette A.; Kelly, Michael; Wack, Edward; Ryan-Howard, Danette; Weidler, Darryl; O'Brien, Peter; Colonero, Curtis; Lakness, John; Patel, Paras

2005-11-01

In order to meet current and emerging needs for remote passive standoff detection of chemical agent threats, MIT Lincoln Laboratory has developed a Wide Area Chemical Sensor (WACS) testbed. A design study helped define the initial concept, guided by current standoff sensor mission requirements. Several variants of this initial design have since been proposed to target other applications within the defense community. The design relies on several enabling technologies required for successful implementation. The primary spectral component is a Wedged Interferometric Spectrometer (WIS) capable of imaging in the LWIR with spectral resolutions as narrow as 4 cm-1. A novel scanning optic will enhance the ability of this sensor to scan over large areas of concern with a compact, rugged design. In this paper, we shall discuss our design, development, and calibration process for this system as well as recent testbed measurements that validate the sensor concept.

Integrated single-walled carbon nanotube/microfluidic devices for the study of the sensing mechanism of nanotube sensors.

PubMed

Fu, Qiang; Liu, Jie

2005-07-21

A method to fabricate integrated single-walled carbon nanotube/microfluidic devices was developed. This simple process could be used to directly prepare nanotube thin film transistors within the microfluidic channel and to register SWNT devices with the microfludic channel without the need of an additional alignment step. The microfluidic device was designed to have several inlets that deliver multiple liquid flows to a single main channel. The location and width of each flow in the main channel could be controlled by the relative flow rates. This capability enabled us to study the effect of the location and the coverage area of the liquid flow that contained charged molecules on the conduction of the nanotube devices, providing important information on the sensing mechanism of carbon nanotube sensors. The results showed that in a sensor based on a nanotube thin film field effect transistor, the sensing signal came from target molecules absorbed on or around the nanotubes. The effect from adsorption on metal electrodes was weak.

Analysis on the Effect of Sensor Views in Image Reconstruction Produced by Optical Tomography System Using Charge-Coupled Device.

PubMed

Jamaludin, Juliza; Rahim, Ruzairi Abdul; Fazul Rahiman, Mohd Hafiz; Mohd Rohani, Jemmy

2018-04-01

Optical tomography (OPT) is a method to capture a cross-sectional image based on the data obtained by sensors, distributed around the periphery of the analyzed system. This system is based on the measurement of the final light attenuation or absorption of radiation after crossing the measured objects. The number of sensor views will affect the results of image reconstruction, where the high number of sensor views per projection will give a high image quality. This research presents an application of charge-coupled device linear sensor and laser diode in an OPT system. Experiments in detecting solid and transparent objects in crystal clear water were conducted. Two numbers of sensors views, 160 and 320 views are evaluated in this research in reconstructing the images. The image reconstruction algorithms used were filtered images of linear back projection algorithms. Analysis on comparing the simulation and experiments image results shows that, with 320 image views giving less area error than 160 views. This suggests that high image view resulted in the high resolution of image reconstruction.

PAS kinase as a nutrient sensor in neuroblastoma and hypothalamic cells required for the normal expression and activity of other cellular nutrient and energy sensors.

PubMed

Hurtado-Carneiro, Verónica; Roncero, Isabel; Blazquez, Enrique; Alvarez, Elvira; Sanz, Carmen

2013-12-01

PAS kinase (PASK) is a nutrient sensor that is highly conserved throughout evolution. PASK-deficient mice reveal a metabolic phenotype similar to that described in S6 kinase-1 S6K1-deficient mice that are protected against obesity. Hypothalamic metabolic sensors, such as AMP-activated protein kinase (AMPK) and the mammalian target of rapamycin (mTOR), play an important role in feeding behavior, the homeostasis of body weight, and energy balance. These sensors respond to changes in nutrient levels in the hypothalamic areas involved in feeding behavior and in neuroblastoma N2A cells, and we have recently reported that those effects are modulated by the anorexigenic peptide glucagon-like peptide-1 (GLP-1). Here, we identified PASK in both N2A cells and rat VMH and LH areas and found that its expression is regulated by glucose and GLP-1. High levels of glucose decreased Pask gene expression. Furthermore, PASK-silenced N2A cells record an impaired response by the AMPK and mTOR/S6K1 pathways to changes in glucose levels. Likewise, GLP-1 effect on the activity of AMPK, S6K1, and other intermediaries of both pathways and the regulatory role at the level of gene expression were also blocked in PASK-silenced cells. The absence of response to low glucose concentrations in PASK-silenced cells correlates with increased ATP content, low expression of mRNA coding for AMPK upstream kinase LKB1, and enhanced activation of S6K1. Our findings indicate that, at least in N2A cells, PASK is a key kinase in GLP-1 actions and exerts a coordinated response with the other metabolic sensors, suggesting that PASK might play an important role in feeding behavior.

Woven electrochemical fabric-based test sensors (WEFTS): a new class of multiplexed electrochemical sensors.

PubMed

Choudhary, Tripurari; Rajamanickam, G P; Dendukuri, Dhananjaya

2015-05-07

We present textile weaving as a new technique for the manufacture of miniature electrochemical sensors with significant advantages over current fabrication techniques. Biocompatible silk yarn is used as the material for fabrication instead of plastics and ceramics used in commercial sensors. Silk yarns are coated with conducting inks and reagents before being handloom-woven as electrodes into patches of fabric to create arrays of sensors, which are then laminated, cut and packaged into individual sensors. Unlike the conventionally used screen-printing, which results in wastage of reagents, yarn coating uses only as much reagent and ink as required. Hydrophilic and hydrophobic yarns are used for patterning so that sample flow is restricted to a small area of the sensor. This simple fluidic control is achieved with readily available materials. We have fabricated and validated individual sensors for glucose and hemoglobin and a multiplexed sensor, which can detect both analytes. Chronoamperometry and differential pulse voltammetry (DPV) were used to detect glucose and hemoglobin, respectively. Industrial quantities of these sensors can be fabricated at distributed locations in the developing world using existing skills and manufacturing facilities. We believe such sensors could find applications in the emerging area of wearable sensors for chemical testing.

Low-voltage organic strain sensor on plastic using polymer/high- K inorganic hybrid gate dielectrics

NASA Astrophysics Data System (ADS)

Jung, Soyoun; Ji, Taeksoo; Varadan, Vijay K.

2007-12-01

In this paper, gate-induced pentacene semiconductor strain sensors based on hybrid-gate dielectrics using poly-vinylphenol (PVP) and high-K inorganic, Ta IIO 5 are fabricated on flexible substrates, polyethylene naphthalate (PEN). The Ta IIO 5 gate dielectric layer is combined with a thin PVP layer to obtain very smooth and hydrophobic surfaces which improve the molecular structures of pentacene films. The PVP-Ta IIO 5 hybrid-gate dielectric films exhibit a high dielectric capacitance and low leakage current. The sensors adopting thin film transistor (TFT)-like structures show a significantly reduced operating voltage (~6V), and good device characteristics with a field-effect mobility of 1.89 cm2/V•s, a threshold voltage of -0.5 V, and an on/off ratio of 10 3. The strain sensor, one of the practical applications in large-area organic electronics, was characterized with different bending radii of 50, 40, 30, and 20 mm. The sensor output signals were significantly improved with low-operating voltages.

Highly ordered nanowire arrays on plastic substrates for ultrasensitive flexible chemical sensors.

PubMed

McAlpine, Michael C; Ahmad, Habib; Wang, Dunwei; Heath, James R

2007-05-01

The development of a robust method for integrating high-performance semiconductors on flexible plastics could enable exciting avenues in fundamental research and novel applications. One area of vital relevance is chemical and biological sensing, which if implemented on biocompatible substrates, could yield breakthroughs in implantable or wearable monitoring systems. Semiconducting nanowires (and nanotubes) are particularly sensitive chemical sensors because of their high surface-to-volume ratios. Here, we present a scalable and parallel process for transferring hundreds of pre-aligned silicon nanowires onto plastic to yield highly ordered films for low-power sensor chips. The nanowires are excellent field-effect transistors, and, as sensors, exhibit parts-per-billion sensitivity to NO2, a hazardous pollutant. We also use SiO2 surface chemistries to construct a 'nano-electronic nose' library, which can distinguish acetone and hexane vapours via distributed responses. The excellent sensing performance coupled with bendable plastic could open up opportunities in portable, wearable or even implantable sensors.

Simultaneous Detection of Displacement, Rotation Angle, and Contact Pressure Using Sandpaper Molded Elastomer Based Triple Electrode Sensor

PubMed Central

Sul, Onejae; Lee, Seung-Beck

2017-01-01

In this article, we report on a flexible sensor based on a sandpaper molded elastomer that simultaneously detects planar displacement, rotation angle, and vertical contact pressure. When displacement, rotation, and contact pressure are applied, the contact area between the translating top elastomer electrode and the stationary three bottom electrodes change characteristically depending on the movement, making it possible to distinguish between them. The sandpaper molded undulating surface of the elastomer reduces friction at the contact allowing the sensor not to affect the movement during measurement. The sensor showed a 0.25 mm−1 displacement sensitivity with a ±33 μm accuracy, a 0.027 degree−1 of rotation sensitivity with ~0.95 degree accuracy, and a 4.96 kP−1 of pressure sensitivity. For possible application to joint movement detection, we demonstrated that our sensor effectively detected the up-and-down motion of a human forefinger and the bending and straightening motion of a human arm. PMID:28878166

Simultaneous Detection of Displacement, Rotation Angle, and Contact Pressure Using Sandpaper Molded Elastomer Based Triple Electrode Sensor.

PubMed

Choi, Eunsuk; Sul, Onejae; Lee, Seung-Beck

2017-09-06

In this article, we report on a flexible sensor based on a sandpaper molded elastomer that simultaneously detects planar displacement, rotation angle, and vertical contact pressure. When displacement, rotation, and contact pressure are applied, the contact area between the translating top elastomer electrode and the stationary three bottom electrodes change characteristically depending on the movement, making it possible to distinguish between them. The sandpaper molded undulating surface of the elastomer reduces friction at the contact allowing the sensor not to affect the movement during measurement. The sensor showed a 0.25 mm −1 displacement sensitivity with a ±33 μm accuracy, a 0.027 degree −1 of rotation sensitivity with ~0.95 degree accuracy, and a 4.96 kP −1 of pressure sensitivity. For possible application to joint movement detection, we demonstrated that our sensor effectively detected the up-and-down motion of a human forefinger and the bending and straightening motion of a human arm.

Highly ordered nanowire arrays on plastic substrates for ultrasensitive flexible chemical sensors

NASA Astrophysics Data System (ADS)

McAlpine, Michael C.; Ahmad, Habib; Wang, Dunwei; Heath, James R.

2007-05-01

The development of a robust method for integrating high-performance semiconductors on flexible plastics could enable exciting avenues in fundamental research and novel applications. One area of vital relevance is chemical and biological sensing, which if implemented on biocompatible substrates, could yield breakthroughs in implantable or wearable monitoring systems. Semiconducting nanowires (and nanotubes) are particularly sensitive chemical sensors because of their high surface-to-volume ratios. Here, we present a scalable and parallel process for transferring hundreds of pre-aligned silicon nanowires onto plastic to yield highly ordered films for low-power sensor chips. The nanowires are excellent field-effect transistors, and, as sensors, exhibit parts-per-billion sensitivity to NO2, a hazardous pollutant. We also use SiO2 surface chemistries to construct a `nano-electronic nose' library, which can distinguish acetone and hexane vapours via distributed responses. The excellent sensing performance coupled with bendable plastic could open up opportunities in portable, wearable or even implantable sensors.

Highly ordered nanowire arrays on plastic substrates for ultrasensitive flexible chemical sensors

PubMed Central

McAlpine, Michael C.; Ahmad, Habib; Wang, Dunwei; Heath, James R.

2013-01-01

The development of a robust method for integrating high-performance semiconductors on flexible plastics could enable exciting avenues in fundamental research and novel applications. One area of vital relevance is chemical and biological sensing, which if implemented on biocompatible substrates, could yield breakthroughs in implantable or wearable monitoring systems. Semiconducting nanowires (and nanotubes) are particularly sensitive chemical sensors because of their high surface-to-volume ratios. Here, we present a scalable and parallel process for transferring hundreds of pre-aligned silicon nanowires onto plastic to yield highly ordered films for low-power sensor chips. The nanowires are excellent field-effect transistors, and, as sensors, exhibit parts-per-billion sensitivity to NO2, a hazardous pollutant. We also use SiO2 surface chemistries to construct a ‘nano-electronic nose’ library, which can distinguish acetone and hexane vapours via distributed responses. The excellent sensing performance coupled with bendable plastic could open up opportunities in portable, wearable or even implantable sensors. PMID:17450146

The detection and mapping of oil on a marshy area by a remote luminescent sensor

USGS Publications Warehouse

McFarlane, C.; Watson, R.D.

2005-01-01

Airborne remote sensing can be a cost-effective method for monitoring pollutants in large areas such as occur in oil spills. An opportunity to test a particular method arose when a well ruptured and for 23 days spewed a 90-meter fountain of oil into the air, dispersing the oil over a wide area. The method tested was an airborne luminescence detector with a Fraunhofer Line Discriminator (FLD) which was flown over the affected area 41 days after the well was capped to obtain a map or the deposition pattern. To calibrate the system, samples of Spartina (wire grass) and Phragmites (common reed) were collected from the contaminated area and the oil residues were eluted in cyclohexane and quantitatively analyzed in a fluorescence photometer. Good correlation was observed between the remote sensor (FLD) and the laboratory analysis. Isopleths defining the deposition pattern of oil were drawn from the remote sensing information. A discussion will be presented on the feasibility of using this instrument for similar contamination incidents for cleanup and damage assessment.

Advances in miniature spectrometer and sensor development

NASA Astrophysics Data System (ADS)

Malinen, Jouko; Rissanen, Anna; Saari, Heikki; Karioja, Pentti; Karppinen, Mikko; Aalto, Timo; Tukkiniemi, Kari

2014-05-01

Miniaturization and cost reduction of spectrometer and sensor technologies has great potential to open up new applications areas and business opportunities for analytical technology in hand held, mobile and on-line applications. Advances in microfabrication have resulted in high-performance MEMS and MOEMS devices for spectrometer applications. Many other enabling technologies are useful for miniature analytical solutions, such as silicon photonics, nanoimprint lithography (NIL), system-on-chip, system-on-package techniques for integration of electronics and photonics, 3D printing, powerful embedded computing platforms, networked solutions as well as advances in chemometrics modeling. This paper will summarize recent work on spectrometer and sensor miniaturization at VTT Technical Research Centre of Finland. Fabry-Perot interferometer (FPI) tunable filter technology has been developed in two technical versions: Piezoactuated FPIs have been applied in miniature hyperspectral imaging needs in light weight UAV and nanosatellite applications, chemical imaging as well as medical applications. Microfabricated MOEMS FPIs have been developed as cost-effective sensor platforms for visible, NIR and IR applications. Further examples of sensor miniaturization will be discussed, including system-on-package sensor head for mid-IR gas analyzer, roll-to-roll printed Surface Enhanced Raman Scattering (SERS) technology as well as UV imprinted waveguide sensor for formaldehyde detection.

Humidity effect on organic semiconductor NiPc films deposited at different gravity conditions

NASA Astrophysics Data System (ADS)

Fatima, N.; Ahmed, M. M.; Karimov, Kh. S.; Ahmedov, Kh.

2016-08-01

In this study, thin films of Nickel Phthalocyanine (NiPc) were deposited by centrifugation at high gravity (70g), and also at normal gravity (1g) conditions to fabricate humidity sensors. Ceramic alumina sheet, coated with silver electrodes, having interelectrode distance of 0.2l mm were used to assess the electrical properties of the sensors. Room temperature capacitance and impedance variations were measured as a function of relative humidity ranging from 25% ∼⃒ 95% at 1 kHz frequency. It was observed that sensors fabricated at 70g were more sensitive compared to sensors fabricated at 1g. Sensors fabricated at 70g exhibited 1.8 times decrease in their impedance and1.5 times increase in their capacitance at peak ambient humidity. SEM images showed more roughness for the films deposited at 70g compared to films deposited at 1g. It was assumed that surface irregularities might have increased active surface area of 70g sensors hence changed the electrical response. Impedance-humidity and capacitance-humidity relationships were modeled and a good agreement was observed between experimental and modeled data. Experimental data showed that NiPc films could be useful for instrumentation industry to fabricate organic humidity sensors.

Detection and Classification of UXO Using Unmanned Undersea Electromagnetic Sensing Platforms

NASA Astrophysics Data System (ADS)

Schultz, G.; Keranen, J.; McNinch, J.; Miller, J.

2017-12-01

Important seafloor applications, including mine countermeasures, unexploded ordnance (UXO) surveys, salvage, and underwater hazards, require the detection, geo-registration, and characterization of man-made targets on, or below, the seafloor. Investigations in littoral environments can be time-consuming and expensive due to the challenges of accurately tracking underwater assets, the difficulty of quick or effective site reconnaissance activities, high levels of clutter in nearshore areas, and lack of situational awareness and real-time feedback to operators. Consequently, a high payoff exists for effective methods using sensor and data fusion, feature extraction, and effective payload integration and deployment for improved assessments of littoral infrastructure. We present technology development and demonstration results from multiple technology research, development, and demonstration projects over the last 3 years that have been focused on advancing seafloor target detection, tracking, and classification for specific environmental and defense missions. We focus on challenges overcome in integrating and testing new miniaturized passive magnetic and controlled-source electromagnetic sensors on a variety of remotely and autonomously operated sensing platforms (ROVs, AUVs and bottom crawling systems). In particular, we present aspects of the design, development, and testing of array configurations of miniaturized atomic magnetometers/gradiometers and multi-dimensional electromagnetic (EM) sensor arrays. Results from nearshore (surf zone and marsh in North Carolina) and littoral experiments (bays and reef areas of Florida Gulf and Florida Keys) are presented.

Technical Assessment: Autonomy

DTIC Science & Technology

2015-02-23

low-cost sensors for automotive applications, mobile devices, and video games . If DoD develops CONOPS for lower- performance systems, there is an...advancement in this area is Microsoft’s Kinect technology. While originally designed for the Xbox video game platform, it is now being used or developed for...One area worthy of consideration is applied game theory, which may allow systems to effectively respond to adversary actions. Recommendation 4

Low-power secure body area network for vital sensors toward IEEE802.15.6.

PubMed

Kuroda, Masahiro; Qiu, Shuye; Tochikubo, Osamu

2009-01-01

Many healthcare/medical services have started using personal area networks, such as Bluetooth and ZigBee; these networks consist of various types of vital sensors. These works focus on generalized functions for sensor networks that expect enough battery capacity and low-power CPU/RF (Radio Frequency) modules, but less attention to easy-to-use privacy protection. In this paper, we propose a commercially-deployable secure body area network (S-BAN) with reduced computational burden on a real sensor that has limited RAM/ROM sizes and CPU/RF power consumption under a light-weight battery. Our proposed S-BAN provides vital data ordering among sensors that are involved in an S-BAN and also provides low-power networking with zero-administration security by automatic private key generation. We design and implement the power-efficient media access control (MAC) with resource-constraint security in sensors. Then, we evaluate the power efficiency of the S-BAN consisting of small sensors, such as an accessory type ECG and ring-type SpO2. The evaluation of power efficiency of the S-BAN using real sensors convinces us in deploying S-BAN and will also help us in providing feedbacks to the IEEE802.15.6 MAC, which will be the standard for BANs.

Evaluation of physical properties of different digital intraoral sensors.

PubMed

Al-Rawi, Wisam; Teich, Sorin

2013-09-01

Digital technologies provide clinically acceptable results comparable to traditional films while having other advantages such as the ability to store and manipulate images, immediate evaluation of the image diagnostic quality, possible reduction in patient radiation exposure, and so on. The purpose of this paper is to present the results of the evaluation of the physical design of eight CMOS digital intraoral sensors. Sensors tested included: XDR (Cyber Medical Imaging, Los Angeles, CA, USA), RVG 6100 (Carestream Dental LLC, Atlanta, GA, USA), Platinum (DEXIS LLC., Hatfield, PA, USA), CDR Elite (Schick Technologies, Long Island City, NY, USA), ProSensor (Planmeca, Helsinki, Finland), EVA (ImageWorks, Elmsford, NY, USA), XIOS Plus (Sirona, Bensheim, Germany), and GXS-700 (Gendex Dental Systems, Hatfield, PA, USA). The sensors were evaluated for cable configuration, connectivity interface, presence of back-scattering radiation shield, plate thickness, active sensor area, and comparing the active imaging area to the outside casing and to conventional radiographic films. There were variations among the physical design of different sensors. For most parameters tested, a lack of standardization exists in the industry. The results of this study revealed that these details are not always available through the material provided by the manufacturers and are often not advertised. For all sensor sizes, active imaging area was smaller compared with conventional films. There was no sensor in the group that had the best physical design. Data presented in this paper establishes a benchmark for comparing the physical design of digital intraoral sensors.

Design and development of LED-based irregular leather area measuring machine

NASA Astrophysics Data System (ADS)

Adil, Rehan; Khan, Sarah Jamal

2012-01-01

Using optical sensor array, a precision motion control system in a conveyer follows the irregular shaped leather sheet to measure its surface area. In operation, irregular shaped leather sheet passes on conveyer belt and optical sensor array detects the leather sheet edge. In this way outside curvature of the leather sheet is detected and is then feed to the controller to measure its approximate area. Such system can measure irregular shapes, by neglecting rounded corners, ellipses etc. To minimize the error in calculating surface area of irregular curve to the above mentioned system, the motion control system only requires the footprint of the optical sensor to be small and the distance between the sensors is to be minimized. In the proposed technique surface area measurement of irregular shaped leather sheet is done by defining velocity and detecting position of the move. The motion controller takes the information and creates the necessary edge profile on point-to-point bases. As a result irregular shape of leather sheet is mapped and is then feed to the controller to calculate surface area.

Three-Axis Ground Reaction Force Distribution during Straight Walking.

PubMed

Hori, Masataka; Nakai, Akihito; Shimoyama, Isao

2017-10-24

We measured the three-axis ground reaction force (GRF) distribution during straight walking. Small three-axis force sensors composed of rubber and sensor chips were fabricated and calibrated. After sensor calibration, 16 force sensors were attached to the left shoe. The three-axis force distribution during straight walking was measured, and the local features of the three-axis force under the sole of the shoe were analyzed. The heel area played a role in receiving the braking force, the base area of the fourth and fifth toes applied little vertical or shear force, the base area of the second and third toes generated a portion of the propulsive force and received a large vertical force, and the base area of the big toe helped move the body's center of mass to the other foot. The results demonstrate that measuring the three-axis GRF distribution is useful for a detailed analysis of bipedal locomotion.

Performance enhanced piezoelectric-based crack detection system for high temperature I-beam SHM

NASA Astrophysics Data System (ADS)

Zhang, Chen; Zhang, Haifeng

2017-04-01

This paper proposes an innovative sensing system for high temperature (up to 150°C) I-beam crack detection. The proposed system is based on the piezoelectric effect and laser sensing mechanisms, which is proved to be effective at high temperature environment (up to 150°C). Different from other high temperature SHM approaches, the proposed sensing system is employing a piezoelectric disk as an actuator and a laser vibrometer as a sensor for remote detection. Lab tests are carried out and the vibrational properties are studied to characterize the relationship between crack depth and sensor responses by analyzing the RMS of sensor responses. Instead of utilizing a pair of piezoelectric actuator and sensor, using the laser vibrometer will enable 1) a more flexible detection, which will not be limited to specific area or dimension, 2) wireless sensing, which lowers the risk of operating at high temperature/harsh environment. The proposed sensing system can be applied to engineering structures such as in nuclear power plant reactor vessel and heat pipe structures/systems.

Electrochemical Sensors and Biosensors Based on Nanomaterials and Nanostructures

DOE PAGES

Zhu, Chengzhou; Yang, Guohai; Li, He; ...

2014-10-29

We report that considerable attention has been devoted to the integration of recognition elements with electronic elements to develop electrochemical sensors and biosensors.Various electrochemical devices, such as amperometric sensors, electrochemical impedance sensors, and electrochemical luminescence sensors as well as photoelectrochemical sensors, provide wide applications in the detection of chemical and biological targets in terms of electrochemical change of electrode interfaces. Here, this review focuses on recent advances in electrochemical sensors and biosensors based on nanomaterials and nanostructures during 2013 to 2014. The aim of this effort is to provide the reader with a clear and concise view of new advancesmore » in areas ranging from electrode engineering, strategies for electrochemical signal amplification, and novel electroanalytical techniques used in the miniaturization and integration of the sensors. Moreover, the authors have attempted to highlight areas of the latest and significant development of enhanced electrochemical nanosensors and nanobiosensors that inspire broader interests across various disciplines. Electrochemical sensors for small molecules, enzyme-based biosensors, genosensors, immunosensors, and cytosensors are reviewed herein (Figure 1). Such novel advances are important for the development of electrochemical sensors that open up new avenues and methods for future research. In conclusion, we recommend readers interested in the general principles of electrochemical sensors and electrochemical methods to refer to other excellent literature for a broad scope in this area.(3, 4) However, due to the explosion of publications in this active field, we do not claim that this Review includes all of the published works in the past two years and we apologize to the authors of excellent work, which is unintentionally left out.« less

Influence of the middle ear anatomy on the performance of a membrane sensor in the incudostapedial joint gap.

PubMed

Koch, Martin; Seidler, Hannes; Hellmuth, Alexander; Bornitz, Matthias; Lasurashvili, Nikoloz; Zahnert, Thomas

2013-07-01

There is a great demand for implantable microphones for future generations of implantable hearing aids, especially Cochlea Implants. An implantable middle ear microphone based on a piezoelectric membrane sensor for insertion into the incudostapedial gap is investigated. The sensor is designed to measure the sound-induced forces acting on the center of the membrane. The sensor mechanically couples to the adjacent ossicles via two contact areas, the sensor membrane and the sensor housing. The sensing element is a piezoelectric single crystal bonded on a titanium membrane. The sensor allows a minimally invasive and reversible implantation without removal of ossicles and without additional sensor fixation in the tympanic cavity. This study investigates the implantable microphone sensor and its implantation concept. It intends to quantify the influence of the sensor's insertion position on the achievable microphone sensitivity. The investigation considers anatomical and pathological variations of the middle ear geometry and its space limitations. Temporal bone experiments on a laboratory model show that anatomical and pathological variations of the middle ear geometry can prevent the sensor from being placed optimally within the incudostapedial joint. Beyond scattering of transfer functions due to anatomic variations of individual middle ears there is the impact of variations in the sensor position within the ossicular chain that has a considerable effect on the transfer characteristics of the middle ear microphone. The centering of the sensor between incus and stapes, the direction of insertion (membrane to stapes or to incus) and the effect of additional contact points with surrounding anatomic structures affect the signal yield of the implanted sensor. The presence of additional contact points has a considerably impact on the sensitivity, yet the microphone sensitivity is quite robust against small changes in the positioning of the incus on the sensor. Signal losses can be avoided by adjusting the position of the sensor within the joint. The findings allow the development of an improved surgical insertion technique to ensure maximally achievable signal yield of the membrane sensor in the ISJ and provides valuable knowledge for a future design considerations including sensor miniaturization and geometry. Measurements of the implanted sensor in temporal bone specimens showed a microphone sensitivity in the order of 1 mV/Pa. This article is part of a special issue entitled "MEMRO 2012". Copyright © 2012 Elsevier B.V. All rights reserved.

Experimental Performance of a Micromachined Heat Flux Sensor

NASA Technical Reports Server (NTRS)

Stefanescu, S.; DeAnna, R. G.; Mehregany, M.

1998-01-01

Steady-state and frequency response calibration of a microfabricated heat-flux sensor have been completed. This sensor is batch fabricated using standard, micromachining techniques, allowing both miniaturization and the ability to create arrays of sensors and their corresponding interconnects. Both high-frequency and spatial response is desired, so the sensors are both thin and of small cross-sectional area. Thin-film, temperature-sensitive resistors are used as the active gauge elements. Two sensor configurations are investigated: (1) a Wheatstone-bridge using four resistors; and (2) a simple, two-resistor design. In each design, one resistor (or pair) is covered by a thin layer (5000 A) thermal barrier; the other resistor (or pair) is covered by a thick (5 microns) thermal barrier. The active area of a single resistor is 360 microns by 360 microns; the total gauge area is 1.5 mm square. The resistors are made of 2000 A-thick metal; and the entire gauge is fabricated on a 25 microns-thick flexible, polyimide substrate. Heat flux through the surface changes the temperature of the resistors and produces a corresponding change in resistance. Sensors were calibrated using two radiation heat sources: (1) a furnace for steady-state, and (2) a light and chopper for frequency response.

Imaging Radar Applications in the Death Valley Region

NASA Technical Reports Server (NTRS)

Farr, Tom G.

1996-01-01

Death Valley has had a long history as a testbed for remote sensing techniques (Gillespie, this conference). Along with visible-near infrared and thermal IR sensors, imaging radars have flown and orbited over the valley since the 1970's, yielding new insights into the geologic applications of that technology. More recently, radar interferometry has been used to derive digital topographic maps of the area, supplementing the USGS 7.5' digital quadrangles currently available for nearly the entire area. As for their shorter-wavelength brethren, imaging radars were tested early in their civilian history in Death Valley because it has a variety of surface types in a small area without the confounding effects of vegetation. In one of the classic references of these early radar studies, in a semi-quantitative way the response of an imaging radar to surface roughness near the radar wavelength, which typically ranges from about 1 cm to 1 m was explained. This laid the groundwork for applications of airborne and spaceborne radars to geologic problems in and regions. Radar's main advantages over other sensors stems from its active nature- supplying its own illumination makes it independent of solar illumination and it can also control the imaging geometry more accurately. Finally, its long wavelength allows it to peer through clouds, eliminating some of the problems of optical sensors, especially in perennially cloudy and polar areas.

Photodiode area effect on performance of X-ray CMOS active pixel sensors

NASA Astrophysics Data System (ADS)

Kim, M. S.; Kim, Y.; Kim, G.; Lim, K. T.; Cho, G.; Kim, D.

2018-02-01

Compared to conventional TFT-based X-ray imaging devices, CMOS-based X-ray imaging sensors are considered next generation because they can be manufactured in very small pixel pitches and can acquire high-speed images. In addition, CMOS-based sensors have the advantage of integration of various functional circuits within the sensor. The image quality can also be improved by the high fill-factor in large pixels. If the size of the subject is small, the size of the pixel must be reduced as a consequence. In addition, the fill factor must be reduced to aggregate various functional circuits within the pixel. In this study, 3T-APS (active pixel sensor) with photodiodes of four different sizes were fabricated and evaluated. It is well known that a larger photodiode leads to improved overall performance. Nonetheless, if the size of the photodiode is > 1000 μm2, the degree to which the sensor performance increases as the photodiode size increases, is reduced. As a result, considering the fill factor, pixel-pitch > 32 μm is not necessary to achieve high-efficiency image quality. In addition, poor image quality is to be expected unless special sensor-design techniques are included for sensors with a pixel pitch of 25 μm or less.

An approach to improving the signal-to-optical-noise ratio of pulsed magnetic field photonic sensors

NASA Astrophysics Data System (ADS)

Wang, Jiang-ping; Li, Yu-quan

2008-12-01

During last years, interest in pulsed magnetic field sensors has widely increased. In fact, magnetic field measurement has a critical part in various scientific and technical areas. In order to research on pulsed magnetic field characteristic and corresponding measuring and defending means, a sensor with high immunity to electrical noise, high sensitivity, high accuracy and wide dynamic range is needed. The conventional magnetic field measurement system currently use active metallic probes which can disturb the measuring magnetic field and make sensor very sensitive to electromagnetic noise. Photonic magnetic field sensor exhibit great advantages with respect to the electronic ones: a very good galvanic insulation, high sensitivity and very wide bandwidth. Photonic sensing technology is fit for demand of a measure pulsed magnetic field. A type of pulsed magnetic field photonic sensor has been designed, analyzed, and tested. The cross polarization angle in photonic sensor effect on the signal-to-optical-noise ratio is theoretically analyzed in this paper. A novel approach for improving the signal-to-optical-noise ratio of pulsed magnetic field sensors was proposed. The experiments have proved that this approach is practical. The theoretical analysis and simulation results show that the signal-to-optical-noise ratio can potentially be considerably improved by setup suitable for the cross polarization angle.

The Coverage Problem in Video-Based Wireless Sensor Networks: A Survey

PubMed Central

Costa, Daniel G.; Guedes, Luiz Affonso

2010-01-01

Wireless sensor networks typically consist of a great number of tiny low-cost electronic devices with limited sensing and computing capabilities which cooperatively communicate to collect some kind of information from an area of interest. When wireless nodes of such networks are equipped with a low-power camera, visual data can be retrieved, facilitating a new set of novel applications. The nature of video-based wireless sensor networks demands new algorithms and solutions, since traditional wireless sensor networks approaches are not feasible or even efficient for that specialized communication scenario. The coverage problem is a crucial issue of wireless sensor networks, requiring specific solutions when video-based sensors are employed. In this paper, it is surveyed the state of the art of this particular issue, regarding strategies, algorithms and general computational solutions. Open research areas are also discussed, envisaging promising investigation considering coverage in video-based wireless sensor networks. PMID:22163651

Fiber optic sensor based on Mach-Zehnder interferometer for securing entrance areas of buildings

NASA Astrophysics Data System (ADS)

Nedoma, Jan; Fajkus, Marcel; Martinek, Radek; Mec, Pavel; Novak, Martin; Bednarek, Lukas; Vasinek, Vladimir

2017-10-01

Authors of this article focused on the utilization of fiber optic sensors based on interferometric measurements for securing entrance areas of buildings such as windows and doors. We described the implementation of the fiber-optic interferometer (type Mach-Zehnder) into the window frame or door, sensor sensitivity, analysis of the background noise and methods of signal evaluation. The advantage of presented solution is the use of standard telecommunication fiber standard G.652.D, high sensitivity, immunity of sensor to electromagnetic interference (EMI) and passivity of the sensor regarding power supply. Authors implemented the Graphical User Interface (GUI) which offers the possibility of remote monitoring presented sensing solution.

Application of EREP, LANDSAT, and aircraft image data to environmental problems related to coal mining

NASA Technical Reports Server (NTRS)

Amato, R. V.; Russell, O. R.; Martin, K. R.; Wier, C. E.

1975-01-01

Remote sensing techniques were used to study coal mining sites within the Eastern Interior Coal Basin (Indiana, Illinois, and western Kentucky), the Appalachian Coal Basin (Ohio, West Virginia, and Pennsylvania) and the anthracite coal basins of northeastern Pennsylvania. Remote sensor data evaluated during these studies were acquired by LANDSAT, Skylab and both high and low altitude aircraft. Airborne sensors included multispectral scanners, multiband cameras and standard mapping cameras loaded with panchromatic, color and color infrared films. The research conducted in these areas is a useful prerequisite to the development of an operational monitoring system that can be peridically employed to supply state and federal regulatory agencies with supportive data. Further research, however, must be undertaken to systematically examine those mining processes and features that can be monitored cost effectively using remote sensors and for determining what combination of sensors and ground sampling processes provide the optimum combination for an operational system.

Integrating modelling and smart sensors for environmental and human health

PubMed Central

Reis, Stefan; Seto, Edmund; Northcross, Amanda; Quinn, Nigel W.T.; Convertino, Matteo; Jones, Rod L.; Maier, Holger R.; Schlink, Uwe; Steinle, Susanne; Vieno, Massimo; Wimberly, Michael C.

2015-01-01

Sensors are becoming ubiquitous in everyday life, generating data at an unprecedented rate and scale. However, models that assess impacts of human activities on environmental and human health, have typically been developed in contexts where data scarcity is the norm. Models are essential tools to understand processes, identify relationships, associations and causality, formalize stakeholder mental models, and to quantify the effects of prevention and interventions. They can help to explain data, as well as inform the deployment and location of sensors by identifying hotspots and areas of interest where data collection may achieve the best results. We identify a paradigm shift in how the integration of models and sensors can contribute to harnessing ‘Big Data’ and, more importantly, make the vital step from ‘Big Data’ to ‘Big Information’. In this paper, we illustrate current developments and identify key research needs using human and environmental health challenges as an example. PMID:26644778

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

PubMed

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

2017-11-13

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

Ares I Scale Model Acoustic Tests Instrumentation for Acoustic and Pressure Measurements

NASA Technical Reports Server (NTRS)

Vargas, Magda B.; Counter, Douglas D.

2011-01-01

The Ares I Scale Model Acoustic Test (ASMAT) was a development test performed at the Marshall Space Flight Center (MSFC) East Test Area (ETA) Test Stand 116. The test article included a 5% scale Ares I vehicle model and tower mounted on the Mobile Launcher. Acoustic and pressure data were measured by approximately 200 instruments located throughout the test article. There were four primary ASMAT instrument suites: ignition overpressure (IOP), lift-off acoustics (LOA), ground acoustics (GA), and spatial correlation (SC). Each instrumentation suite incorporated different sensor models which were selected based upon measurement requirements. These requirements included the type of measurement, exposure to the environment, instrumentation check-outs and data acquisition. The sensors were attached to the test article using different mounts and brackets dependent upon the location of the sensor. This presentation addresses the observed effect of the sensors and mounts on the acoustic and pressure measurements.

Effects of instrument characteristics on cloud properties retrieved from satellite imagery data

NASA Technical Reports Server (NTRS)

Baldwin, D. G.; Coakley, J. A., Jr.; Zhang, M. S.

1986-01-01

The relationships between sensor resolution and derived cloud properties in satellite remote sensing were studied by comparisons of cloud characteristics determined by spatial coherence analysis of AVHRR and GOES data. The latter data were simulated from 11 microns AVHRR data and were assigned a resolution (8 sq km) half that of the AVHRR. Day and nighttime passes were considered for single-layer maritime cloud systems. Sample radiance vs local standard deviation plots of 1024 points are provided for the same area from AVHRR and GOES-East sensors, demonstrating a qualitative agreement.

A wireless sensor enabled by wireless power.

PubMed

Lee, Da-Sheng; Liu, Yu-Hong; Lin, Chii-Ruey

2012-11-22

Through harvesting energy by wireless charging and delivering data by wireless communication, this study proposes the concept of a wireless sensor enabled by wireless power (WPWS) and reports the fabrication of a prototype for functional tests. One WPWS node consists of wireless power module and sensor module with different chip-type sensors. Its main feature is the dual antenna structure. Following RFID system architecture, a power harvesting antenna was designed to gather power from a standard reader working in the 915 MHz band. Referring to the Modbus protocol, the other wireless communication antenna was integrated on a node to send sensor data in parallel. The dual antenna structure integrates both the advantages of an RFID system and a wireless sensor. Using a standard UHF RFID reader, WPWS can be enabled in a distributed area with a diameter up to 4 m. Working status is similar to that of a passive tag, except that a tag can only be queried statically, while the WPWS can send dynamic data from the sensors. The function is the same as a wireless sensor node. Different WPWSs equipped with temperature and humidity, optical and airflow velocity sensors are tested in this study. All sensors can send back detection data within 8 s. The accuracy is within 8% deviation compared with laboratory equipment. A wireless sensor network enabled by wireless power should be a totally wireless sensor network using WPWS. However, distributed WPWSs only can form a star topology, the simplest topology for constructing a sensor network. Because of shielding effects, it is difficult to apply other complex topologies. Despite this limitation, WPWS still can be used to extend sensor network applications in hazardous environments. Further research is needed to improve WPWS to realize a totally wireless sensor network.

A Wireless Sensor Enabled by Wireless Power

PubMed Central

Lee, Da-Sheng; Liu, Yu-Hong; Lin, Chii-Ruey

2012-01-01

Through harvesting energy by wireless charging and delivering data by wireless communication, this study proposes the concept of a wireless sensor enabled by wireless power (WPWS) and reports the fabrication of a prototype for functional tests. One WPWS node consists of wireless power module and sensor module with different chip-type sensors. Its main feature is the dual antenna structure. Following RFID system architecture, a power harvesting antenna was designed to gather power from a standard reader working in the 915 MHz band. Referring to the Modbus protocol, the other wireless communication antenna was integrated on a node to send sensor data in parallel. The dual antenna structure integrates both the advantages of an RFID system and a wireless sensor. Using a standard UHF RFID reader, WPWS can be enabled in a distributed area with a diameter up to 4 m. Working status is similar to that of a passive tag, except that a tag can only be queried statically, while the WPWS can send dynamic data from the sensors. The function is the same as a wireless sensor node. Different WPWSs equipped with temperature and humidity, optical and airflow velocity sensors are tested in this study. All sensors can send back detection data within 8 s. The accuracy is within 8% deviation compared with laboratory equipment. A wireless sensor network enabled by wireless power should be a totally wireless sensor network using WPWS. However, distributed WPWSs only can form a star topology, the simplest topology for constructing a sensor network. Because of shielding effects, it is difficult to apply other complex topologies. Despite this limitation, WPWS still can be used to extend sensor network applications in hazardous environments. Further research is needed to improve WPWS to realize a totally wireless sensor network. PMID:23443370

Understanding social and behavioral drivers and impacts of air quality sensor use.

PubMed

Hubbell, Bryan J; Kaufman, Amanda; Rivers, Louie; Schulte, Kayla; Hagler, Gayle; Clougherty, Jane; Cascio, Wayne; Costa, Dan

2018-04-15

Lower-cost air quality sensors (hundreds to thousands of dollars) are now available to individuals and communities. This technology is undergoing a rapid and fragmented evolution, resulting in sensors that have uncertain data quality, measure different air pollutants and possess a variety of design attributes. Why and how individuals and communities choose to use sensors is arguably influenced by social context. For example, community experiences with environmental exposures and health effects and related interactions with industry and government can affect trust in traditional air quality monitoring. To date, little social science research has been conducted to evaluate why or how sensors, and sensor data, are used by individuals and communities, or how the introduction of sensors changes the relationship between communities and air quality managers. This commentary uses a risk governance/responsible innovation framework to identify opportunities for interdisciplinary research that brings together social scientists with air quality researchers involved in developing, testing, and deploying sensors in communities. Potential areas for social science research include communities of sensor users; drivers for use of sensors and sensor data; behavioral, socio-political, and ethical implications of introducing sensors into communities; assessing methods for communicating sensor data; and harnessing crowdsourcing capabilities to analyze sensor data. Social sciences can enhance understanding of perceptions, attitudes, behaviors, and other human factors that drive levels of engagement with and trust in different types of air quality data. New transdisciplinary research bridging social sciences, natural sciences, engineering, and design fields of study, and involving citizen scientists working with professionals from a variety of backgrounds, can increase our understanding of air sensor technology use and its impacts on air quality and public health. Published by Elsevier B.V.

Chemical Gas Sensors for Aeronautic and Space Applications

NASA Technical Reports Server (NTRS)

Hunter, Gary W.; Chen, Liang-Yu; Neudeck, Philip G.; Knight, Dak; Liu, Chung-Chiun; Wu, Quing-Hai; Zhou, Huan-Jun

1997-01-01

Aeronautic and space applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. Two areas of particular interest are safety monitoring and emission monitoring. In safety monitoring, detection of low concentrations of hydrogen at potentially low temperatures is important while for emission monitoring the detection of nitrogen oxides, hydrogen, hydrocarbons and oxygen is of interest. This paper discusses the needs of aeronautic and space applications and the point-contact sensor technology being developed to address these needs. The development of these sensors is based on progress in two types of technology: (1) Micromachining and microfabrication technology to fabricate miniaturized sensors. (2) The development of high temperature semiconductors, especially silicon carbide. The detection of each type of gas involves its own challenges in the fields of materials science and fabrication technology. The number of dual-use commercial applications of this microfabricated gas sensor technology make this general area of sensor development a field of significant interest.

Sensor Fusion and Smart Sensor in Sports and Biomedical Applications

PubMed Central

Mendes, José Jair Alves; Vieira, Mário Elias Marinho; Pires, Marcelo Bissi; Stevan, Sergio Luiz

2016-01-01

The following work presents an overview of smart sensors and sensor fusion targeted at biomedical applications and sports areas. In this work, the integration of these areas is demonstrated, promoting a reflection about techniques and applications to collect, quantify and qualify some physical variables associated with the human body. These techniques are presented in various biomedical and sports applications, which cover areas related to diagnostics, rehabilitation, physical monitoring, and the development of performance in athletes, among others. Although some applications are described in only one of two fields of study (biomedicine and sports), it is very likely that the same application fits in both, with small peculiarities or adaptations. To illustrate the contemporaneity of applications, an analysis of specialized papers published in the last six years has been made. In this context, the main characteristic of this review is to present the largest quantity of relevant examples of sensor fusion and smart sensors focusing on their utilization and proposals, without deeply addressing one specific system or technique, to the detriment of the others. PMID:27669260

50 CFR 218.170 - Specified activity and specified geographical area and effective dates.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., and UUV engine noise): Acoustic energy from engines usually from 50 Hz to 10 kHz at SLs less than 170..., classification and localization 05 4520 1510 Non-Navy testing 5 5 5 Acoustic & non-acoustic sensors (magnetic...

50 CFR 218.170 - Specified activity and specified geographical area and effective dates.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., and UUV engine noise): Acoustic energy from engines usually from 50 Hz to 10 kHz at SLs less than 170..., classification and localization 05 4520 1510 Non-Navy testing 5 5 5 Acoustic & non-acoustic sensors (magnetic...

50 CFR 218.170 - Specified activity and specified geographical area and effective dates.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., and UUV engine noise): Acoustic energy from engines usually from 50 Hz to 10 kHz at SLs less than 170..., classification and localization 05 4520 1510 Non-Navy testing 5 5 5 Acoustic & non-acoustic sensors (magnetic...

Freeway travel time estimation using existing fixed traffic sensors : phase 1.

DOT National Transportation Integrated Search

2013-08-01

Freeway travel time is one of the most useful pieces of information for road users and an : important measure of effectiveness (MOE) for traffic engineers and policy makers. In the Greater : St. Louis area, Gateway Guide, the St. Louis Transportation...

Boundary layer measurements using hot-film sensors

NASA Technical Reports Server (NTRS)

Holmes, Harlan K.; Carraway, Debra L.

1986-01-01

Measurements in the aerodynamic boundary layer using heat transfer, hot-film sensors are receiving a significant amount of effort at the Langley Research Center. A description of the basic sensor, the signal conditioning employed, and several manifestations of the sensor are given. Results of a flow reversal sensor development are presented, and future work areas are outlined.

1984-1995 Evolution of Stratospheric Aerosol Size, Surface Area, and Volume Derived by Combining SAGE II and CLAES Extinction Measurements

NASA Technical Reports Server (NTRS)

Russell, Philip B.; Bauman, Jill J.

2000-01-01

This SAGE II Science Team task focuses on the development of a multi-wavelength, multi- sensor Look-Up-Table (LUT) algorithm for retrieving information about stratospheric aerosols from global satellite-based observations of particulate extinction. The LUT algorithm combines the 4-wavelength SAGE II extinction measurements (0.385 <= lambda <= 1.02 microns) with the 7.96 micron and 12.82 micron extinction measurements from the Cryogenic Limb Array Etalon Spectrometer (CLAES) instrument, thus increasing the information content available from either sensor alone. The algorithm uses the SAGE II/CLAES composite spectra in month-latitude-altitude bins to retrieve values and uncertainties of particle effective radius R(sub eff), surface area S, volume V and size distribution width sigma(sub g).

Interference Mitigation Schemes for Wireless Body Area Sensor Networks: A Comparative Survey

PubMed Central

Le, Thien T.T.; Moh, Sangman

2015-01-01

A wireless body area sensor network (WBASN) consists of a coordinator and multiple sensors to monitor the biological signals and functions of the human body. This exciting area has motivated new research and standardization processes, especially in the area of WBASN performance and reliability. In scenarios of mobility or overlapped WBASNs, system performance will be significantly degraded because of unstable signal integrity. Hence, it is necessary to consider interference mitigation in the design. This survey presents a comparative review of interference mitigation schemes in WBASNs. Further, we show that current solutions are limited in reaching satisfactory performance, and thus, more advanced solutions should be developed in the future. PMID:26110407

Remote sensing techniques to assess active fire characteristics and post-fire effects

Treesearch

Leigh B. Lentile; Zachary A. Holden; Alistair M. S. Smith; Michael J. Falkowski; Andrew T. Hudak; Penelope Morgan; Sarah A. Lewis; Paul E. Gessler; Nate C. Benson

2006-01-01

Space and airborne sensors have been used to map area burned, assess characteristics of active fires, and characterize post-fire ecological effects. Confusion about fire intensity, fire severity, burn severity, and related terms can result in the potential misuse of the inferred information by land managers and remote sensing practitioners who require unambiguous...

Wireless sensor platform

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshi, Pooran C.; Killough, Stephen M.; Kuruganti, Phani Teja

A wireless sensor platform and methods of manufacture are provided. The platform involves providing a plurality of wireless sensors, where each of the sensors is fabricated on flexible substrates using printing techniques and low temperature curing. Each of the sensors can include planar sensor elements and planar antennas defined using the printing and curing. Further, each of the sensors can include a communications system configured to encode the data from the sensors into a spread spectrum code sequence that is transmitted to a central computer(s) for use in monitoring an area associated with the sensors.

Demonstration and Methodology of Structural Monitoring of Stringer Runs out Composite Areas by Embedded Optical Fiber Sensors and Connectors Integrated during Production in a Composite Plant.

PubMed

Miguel Giraldo, Carlos; Zúñiga Sagredo, Juan; Sánchez Gómez, José; Corredera, Pedro

2017-07-21

Embedding optical fibers sensors into composite structures for Structural Health Monitoring purposes is not just one of the most attractive solutions contributing to smart structures, but also the optimum integration approach that insures maximum protection and integrity of the fibers. Nevertheless this intended integration level still remains an industrial challenge since today there is no mature integration process in composite plants matching all necessary requirements. This article describes the process developed to integrate optical fiber sensors in the Production cycle of a test specimen. The sensors, Bragg gratings, were integrated into the laminate during automatic tape lay-up and also by a secondary bonding process, both in the Airbus Composite Plant. The test specimen, completely representative of the root joint of the lower wing cover of a real aircraft, is comprised of a structural skin panel with the associated stringer run out. The ingress-egress was achieved through the precise design and integration of miniaturized optical connectors compatible with the manufacturing conditions and operational test requirements. After production, the specimen was trimmed, assembled and bolted to metallic plates to represent the real triform and buttstrap, and eventually installed into the structural test rig. The interrogation of the sensors proves the effectiveness of the integration process; the analysis of the strain results demonstrate the good correlation between fiber sensors and electrical gauges in those locations where they are installed nearby, and the curvature and load transfer analysis in the bolted stringer run out area enable demonstration of the consistency of the fiber sensors measurements. In conclusion, this work presents strong evidence of the performance of embedded optical sensors for structural health monitoring purposes, where in addition and most importantly, the fibers were integrated in a real production environment and the ingress-egress issue was solved by the design and integration of miniaturized connectors compatible with the manufacturing and structural test phases.

Demonstration and Methodology of Structural Monitoring of Stringer Runs out Composite Areas by Embedded Optical Fiber Sensors and Connectors Integrated during Production in a Composite Plant

PubMed Central

Miguel Giraldo, Carlos; Zúñiga Sagredo, Juan; Sánchez Gómez, José; Corredera, Pedro

2017-01-01

Embedding optical fibers sensors into composite structures for Structural Health Monitoring purposes is not just one of the most attractive solutions contributing to smart structures, but also the optimum integration approach that insures maximum protection and integrity of the fibers. Nevertheless this intended integration level still remains an industrial challenge since today there is no mature integration process in composite plants matching all necessary requirements. This article describes the process developed to integrate optical fiber sensors in the Production cycle of a test specimen. The sensors, Bragg gratings, were integrated into the laminate during automatic tape lay-up and also by a secondary bonding process, both in the Airbus Composite Plant. The test specimen, completely representative of the root joint of the lower wing cover of a real aircraft, is comprised of a structural skin panel with the associated stringer run out. The ingress-egress was achieved through the precise design and integration of miniaturized optical connectors compatible with the manufacturing conditions and operational test requirements. After production, the specimen was trimmed, assembled and bolted to metallic plates to represent the real triform and buttstrap, and eventually installed into the structural test rig. The interrogation of the sensors proves the effectiveness of the integration process; the analysis of the strain results demonstrate the good correlation between fiber sensors and electrical gauges in those locations where they are installed nearby, and the curvature and load transfer analysis in the bolted stringer run out area enable demonstration of the consistency of the fiber sensors measurements. In conclusion, this work presents strong evidence of the performance of embedded optical sensors for structural health monitoring purposes, where in addition and most importantly, the fibers were integrated in a real production environment and the ingress-egress issue was solved by the design and integration of miniaturized connectors compatible with the manufacturing and structural test phases. PMID:28754009

Location verification algorithm of wearable sensors for wireless body area networks.

PubMed

Wang, Hua; Wen, Yingyou; Zhao, Dazhe

2018-01-01

Knowledge of the location of sensor devices is crucial for many medical applications of wireless body area networks, as wearable sensors are designed to monitor vital signs of a patient while the wearer still has the freedom of movement. However, clinicians or patients can misplace the wearable sensors, thereby causing a mismatch between their physical locations and their correct target positions. An error of more than a few centimeters raises the risk of mistreating patients. The present study aims to develop a scheme to calculate and detect the position of wearable sensors without beacon nodes. A new scheme was proposed to verify the location of wearable sensors mounted on the patient's body by inferring differences in atmospheric air pressure and received signal strength indication measurements from wearable sensors. Extensive two-sample t tests were performed to validate the proposed scheme. The proposed scheme could easily recognize a 30-cm horizontal body range and a 65-cm vertical body range to correctly perform sensor localization and limb identification. All experiments indicate that the scheme is suitable for identifying wearable sensor positions in an indoor environment.

Determination of the Effective Detector Area of an Energy-Dispersive X-Ray Spectrometer at the Scanning Electron Microscope Using Experimental and Theoretical X-Ray Emission Yields.

PubMed

Procop, Mathias; Hodoroaba, Vasile-Dan; Terborg, Ralf; Berger, Dirk

2016-12-01

A method is proposed to determine the effective detector area for energy-dispersive X-ray spectrometers (EDS). Nowadays, detectors are available for a wide range of nominal areas ranging from 10 up to 150 mm2. However, it remains in most cases unknown whether this nominal area coincides with the "net active sensor area" that should be given according to the related standard ISO 15632, or with any other area of the detector device. Moreover, the specific geometry of EDS installation may further reduce a given detector area. The proposed method can be applied to most scanning electron microscope/EDS configurations. The basic idea consists in a comparison of the measured count rate with the count rate resulting from known X-ray yields of copper, titanium, or silicon. The method was successfully tested on three detectors with known effective area and applied further to seven spectrometers from different manufacturers. In most cases the method gave an effective area smaller than the area given in the detector description.

Infrared fiber-optic fire sensors - Concepts and designs for Space Station applications

NASA Technical Reports Server (NTRS)

Tapphorn, Ralph M.; Porter, Alan R.

1990-01-01

Various design configurations used for testing IR fiber-optic (IFO) fire-sensor concepts are presented. Responsibility measurements conducted to select the best concept are reviewed. The results indicate that IFO fire-sensor systems based on distributed fiber sensors are feasible for future aerospace applications. For Space Station Freedom, these systems offer alternative fire detectors for monitoring areas within equipment or stage compartments where the ventilation may be inadequate for proper operation of smoke detectors. They also allow a large number of areas to be monitored by a single central detector unit, which reduces the associated cost and weight.

Fabrication of Highly Sensitive Nonenzymatic Electrochemical H₂O₂ Sensor Based on Pt Nanoparticles Anchored Reduced Graphene Oxide.

PubMed

Dhara, Keerthy; Ramachandran, T; Nair, Bipin G; Babu, T G Satheesh

2018-06-01

A highly sensitive nonenzymatic hydrogen peroxide (H2O2) sensor was fabricated using platinum nanoparticles decorated reduced graphene oxide (Pt/rGO) nanocomposite. The Pt/rGO nanocomposite was prepared by single-step chemical reduction method. Nanocomposite was characterized by various analytical techniques including Raman spectroscopy, X-ray diffraction, field emission scanning electron microscope and high-resolution transmission electron microscopy. Screen printed electrodes (SPEs) were fabricated and the nanocomposite was cast on the working area of the SPE. Cyclic voltammetry and amperometry demonstrated that the Pt/rGO/SPE displayed much higher electrocatalytic activity towards the reduction of H2O2 than the other modified electrodes. The sensor exhibited wide linear detection range (from 10 μM to 8 mM), very high sensitivity of 1848 μA mM-1 cm-2 and a lower limit of detection of 0.06 μM. The excellent performance of Pt/rGO/SPE sensor were attributed to the reduced graphene oxide being used as an effective matrix to load a number of Pt nanoparticles and the synergistic amplification effect of the two kinds of nanomaterials. Moreover, the sensor showed remarkable features such as good reproducibility, repeatability, long-term stability, and selectivity.

Effect of retransmission and retrodiction on estimation and fusion in long-haul sensor networks

DOE PAGES

Liu, Qiang; Wang, Xin; Rao, Nageswara S. V.; ...

2016-01-01

In a long-haul sensor network, sensors are remotely deployed over a large geographical area to perform certain tasks, such as target tracking. In this work, we study the scenario where sensors take measurements of one or more dynamic targets and send state estimates of the targets to a fusion center via satellite links. The severe loss and delay inherent over the satellite channels reduce the number of estimates successfully arriving at the fusion center, thereby limiting the potential fusion gain and resulting in suboptimal accuracy performance of the fused estimates. In addition, the errors in target-sensor data association can alsomore » degrade the estimation performance. To mitigate the effect of imperfect communications on state estimation and fusion, we consider retransmission and retrodiction. The system adopts certain retransmission-based transport protocols so that lost messages can be recovered over time. Besides, retrodiction/smoothing techniques are applied so that the chances of incurring excess delay due to retransmission are greatly reduced. We analyze the extent to which retransmission and retrodiction can improve the performance of delay-sensitive target tracking tasks under variable communication loss and delay conditions. Lastly, simulation results of a ballistic target tracking application are shown in the end to demonstrate the validity of our analysis.« less

Problems of urban development and growth

NASA Technical Reports Server (NTRS)

Gerlach, A. C.; Wray, J. R.

1972-01-01

The increase in the density of human population in urban areas and the effects on various aspects of the environment are discussed. The application of remote sensors to measure, analyze, and predict urban changes and their environmental impact is described. Examples of urban area mapping by aerial photography are included. The methods which have been developed to acquire, analyze, utilize, and preserve remotely sensed data on urban development are presented.

Printable Silicon Nanomembranes for Solar-Powered, Bi-Directional Phased-Array-Antenna Communication System on Flexible Substrates

DTIC Science & Technology

2013-04-01

Identification (RFID), Large Area Flexible Displays, Electronic Paper, Bio - Sensors , Large Area Conformal and Flexible Antennas, Smart and Interactive Textiles...Lepeshkin, R. W. Boyd, C. Chase, and J. E. Fajardo, “An environmental sensor based on an integrated optical whispering gallery mode disk resonator ...Ubiquitous Sensor Networks (USN), Vehicle Clickers Readers, Real Time Locating Systems, Lighting, Photovoltaics etc. FA9550-11-C-0014 STTR Phase II

Vision-Based Traffic Data Collection Sensor for Automotive Applications

PubMed Central

Llorca, David F.; Sánchez, Sergio; Ocaña, Manuel; Sotelo, Miguel. A.

2010-01-01

This paper presents a complete vision sensor onboard a moving vehicle which collects the traffic data in its local area in daytime conditions. The sensor comprises a rear looking and a forward looking camera. Thus, a representative description of the traffic conditions in the local area of the host vehicle can be computed. The proposed sensor detects the number of vehicles (traffic load), their relative positions and their relative velocities in a four-stage process: lane detection, candidates selection, vehicles classification and tracking. Absolute velocities (average road speed) and global positioning are obtained after combining the outputs provided by the vision sensor with the data supplied by the CAN Bus and a GPS sensor. The presented experiments are promising in terms of detection performance and accuracy in order to be validated for applications in the context of the automotive industry. PMID:22315572

Vision-based traffic data collection sensor for automotive applications.

PubMed

Llorca, David F; Sánchez, Sergio; Ocaña, Manuel; Sotelo, Miguel A

2010-01-01

This paper presents a complete vision sensor onboard a moving vehicle which collects the traffic data in its local area in daytime conditions. The sensor comprises a rear looking and a forward looking camera. Thus, a representative description of the traffic conditions in the local area of the host vehicle can be computed. The proposed sensor detects the number of vehicles (traffic load), their relative positions and their relative velocities in a four-stage process: lane detection, candidates selection, vehicles classification and tracking. Absolute velocities (average road speed) and global positioning are obtained after combining the outputs provided by the vision sensor with the data supplied by the CAN Bus and a GPS sensor. The presented experiments are promising in terms of detection performance and accuracy in order to be validated for applications in the context of the automotive industry.

Sensor networks in the low lands.

PubMed

Meratnia, Nirvana; van der Zwaag, Berend Jan; van Dijk, Hylke W; Bijwaard, Dennis J A; Havinga, Paul J M

2010-01-01

This paper provides an overview of scientific and industrial developments of the last decade in the area of sensor networks in The Netherlands (Low Lands). The goal is to highlight areas in which the Netherlands has made most contributions and is currently a dominant player in the field of sensor networks. On the one hand, motivations, addressed topics, and initiatives taken in this period are presented, while on the other hand, special emphasis is given to identifying current and future trends and formulating a vision for the coming five to ten years. The presented overview and trend analysis clearly show that Dutch research and industrial efforts, in line with recent worldwide developments in the field of sensor technology, present a clear shift from sensor node platforms, operating systems, communication, networking, and data management aspects of the sensor networks to reasoning/cognition, control, and actuation.

A Wireless Embedded Sensor based on Magnetic Higher-order Harmonic Fields: Application to Liquid Pressure Monitoring

PubMed Central

Tan, Ee Lim; Pereles, Brandon D.

2010-01-01

A wireless sensor based on the magnetoelastic, magnetically soft ferromagnetic alloy was constructed for remote measurement of pressure in flowing fluids. The pressure sensor was a rectangular strip of ferromagnetic alloy Fe40Ni38Mo4B18 adhered on a solid polycarbonate substrate and protected by a thin polycarbonate film. Upon excitation of a time-varying magnetic field through an excitation coil, the magnetically soft sensor magnetized and produced higher-order harmonic fields, which were detected through a detection coil. Under varying pressures, the sensor's magnetoelastic property caused a change in its magnetization, altering the amplitudes of the higher-order harmonic fields. A theoretical model was developed to describe the effect of pressure on the sensor's higher order harmonic fields. Experimental observations showed the 2nd order harmonic field generated by the pressure sensor was correlated to the surrounding fluid pressure, consistent with the theoretical results. Furthermore, it was demonstrated that the sensor exhibited good repeatability and stability with minimal drift. Sensors with smaller dimensions were shown to have greater sensitivity but lower pressure range as compared to their larger counterparts. Since the sensor signal was also dependent on the location of the sensor with respect to the excitation/detection coil, a calibration algorithm was developed to eliminate signal variations due to the changing sensor location. Because of its wireless and passive nature, this sensor is useful for continuous and long-term monitoring of pressure at inaccessible areas. For example, sensors with these capabilities are suitable to be used in biomedical applications where permanent implantation and long-term monitoring are needed. PMID:20514363

Improved Testing Capability and Adaptability Through the Use of Wireless Sensors

NASA Technical Reports Server (NTRS)

Solano, Wanda M.

2003-01-01

From the first Saturn V rocket booster (S-II-T) testing in 1966 and the routine Space Shuttle Main Engine (SSME) testing beginning in 1975, to more recent test programs such as the X-33 Aerospike Engine, the Integrated Powerhead Development (IPD) program, and the Hybrid Sounding Rocket (HYSR), Stennis Space Center (SSC) continues to be a premier location for conducting large-scale testing. Central to each test program is the capability for sensor systems to deliver reliable measurements and high quality data, while also providing a means to monitor the test stand area to the highest degree of safety and sustainability. Sensor wiring is routed along piping and through cable trenches, making its way from the engine test area, through the test stand area and to the signal conditioning building before final transfer to the test control center. When sensor requirements lie outside the reach of the routine sensor cable routing, the use of wireless sensor networks becomes particularly attractive due to their versatility and ease of installation. As part of an on-going effort to enhance the testing capabilities of Stennis Space Center, the Test Technology and Development group has found numerous applications for its sensor-adaptable wireless sensor suite. While not intended for critical engine measurements or control loops, in-house hardware and software development of the sensor suite can provide improved testing capability for a range of applications including the safety monitoring of propellant storage barrels and as an experimental test-bed for embedded health monitoring paradigms.

The study of concentration effects of target hybridization on cervical cancer detection using interdigitated electrodes (IDE)

NASA Astrophysics Data System (ADS)

Noriani, C.; Hashim, U.; Azizah, N.

2016-07-01

Human Papilloma Virus (HPV) is a virus from the Papilloma virus family that affects human skin and the moist membranes that line the body, such as the throat, mouth, feet, fingers, nails, anus and cervix [1]. There are over 100 types, of which 40 can affect the genital area. Most known HPV types cause no symptoms to humans. Some, however, can cause verrucae (warts), while a small number can increase the risk of developing several cancers, such as that of the cervix, penis, vagina, anus and oropharynx (oral part of the pharynx - throat cancer). HPV strand 16 and 18 are well known for causing the advanced of Cervical Cancer (CC). Currently, integrated electrodes (IDEs) are implemented in various sensing devices including surface acoustic wave (SAW) sensors, chemical sensors as well as current MEMS biosensors. IDEs have been optimized for a variety of sensing applications including biosensors sensors, acoustic sensors, and chemical sensors. However, optimization for cancer cell detection has yet to be reported. The output signal strength of IDEs is controlled through careful design of the active area, width, and spacing of the electrode fingers the efficiency of DNA nanochip depends mainly on the sequence of the capture probes and the way they are attached to the support [2]. This strategy presented a simple, rapid and sensitive platform for HPV detection and would become a powerful tool for pathogenic microorganisms screening in clinical diagnosis. The coupling procedure must be quick, covalent, and reproducible.

Two-Channel SPR Sensor Combined Application of Polymer- and Vitreous-Clad Optic Fibers

PubMed Central

Wei, Yong; Su, Yudong; Liu, Chunlan; Nie, Xiangfei; Liu, Zhihai; Zhang, Yu; Zhang, Yonghui

2017-01-01

By combining a polymer-clad optic fiber and a vitreous-clad optic fiber, we proposed and fabricated a novel optic fiber surface plasmon resonance (SPR) sensor to conduct two-channel sensing at the same detection area. The traditional optic fiber SPR sensor has many disadvantages; for example, removing the cladding requires corrosion, operating it is dangerous, adjusting the dynamic response range is hard, and producing different resonance wavelengths in the sensing area to realize a multi-channel measurement is difficult. Therefore, in this paper, we skillfully used bare fiber grinding technology and reverse symmetry welding technology to remove the cladding in a multi-mode fiber and expose the evanescent field. On the basis of investigating the effect of the grinding angle on the dynamic range change of the SPR resonance valley wavelength and sensitivity, we combined polymer-clad fiber and vitreous-clad fiber by a smart design structure to realize at a single point a two-channel measurement fiber SPR sensor. In this paper, we obtained a beautiful spectral curve from a multi-mode fiber two-channel SPR sensor. In the detection range of the refractive rate between 1.333 RIU and 1.385 RIU, the resonance valley wavelength of channel Ⅰ shifted from 622 nm to 724 nm with a mean average sensitivity of 1961 nm/RIU and the resonance valley wavelength of channel Ⅱ shifted from 741 nm to 976 nm with a mean average sensitivity of 4519 nm/RIU. PMID:29232841

Two-Channel SPR Sensor Combined Application of Polymer- and Vitreous-Clad Optic Fibers.

PubMed

Wei, Yong; Su, Yudong; Liu, Chunlan; Nie, Xiangfei; Liu, Zhihai; Zhang, Yu; Zhang, Yonghui

2017-12-09

By combining a polymer-clad optic fiber and a vitreous-clad optic fiber, we proposed and fabricated a novel optic fiber surface plasmon resonance (SPR) sensor to conduct two-channel sensing at the same detection area. The traditional optic fiber SPR sensor has many disadvantages; for example, removing the cladding requires corrosion, operating it is dangerous, adjusting the dynamic response range is hard, and producing different resonance wavelengths in the sensing area to realize a multi-channel measurement is difficult. Therefore, in this paper, we skillfully used bare fiber grinding technology and reverse symmetry welding technology to remove the cladding in a multi-mode fiber and expose the evanescent field. On the basis of investigating the effect of the grinding angle on the dynamic range change of the SPR resonance valley wavelength and sensitivity, we combined polymer-clad fiber and vitreous-clad fiber by a smart design structure to realize at a single point a two-channel measurement fiber SPR sensor. In this paper, we obtained a beautiful spectral curve from a multi-mode fiber two-channel SPR sensor. In the detection range of the refractive rate between 1.333 RIU and 1.385 RIU, the resonance valley wavelength of channel Ⅰ shifted from 622 nm to 724 nm with a mean average sensitivity of 1961 nm/RIU and the resonance valley wavelength of channel Ⅱ shifted from 741 nm to 976 nm with a mean average sensitivity of 4519 nm/RIU.

Development of a wireless air pollution sensor package for aerial-sampling of emissions

EPA Science Inventory

A new sensor system for mobile and aerial emission sampling was developed for open area pollutant sources, such as prescribed forest burns. The sensor system, termed “Kolibri”, consists of multiple low-cost air quality sensors measuring CO2, CO, samplers for particulate matter wi...

Peptide-nanocellulose sensor for human neutrophil elastase detection

USDA-ARS?s Scientific Manuscript database

Advances in biosensor technology promise to revolutionize healthcare and diagnosis with noninvasive methods. This is especially the case in the area of sensors for wound healing, where approaches for biochemical and cellular markers are emerging. Nanomaterials with high surface area and biocompatibl...

Packaging optical sensors for the real world

NASA Astrophysics Data System (ADS)

Kachmar, Wayne; Nardone, Kenneth C.

2007-09-01

Optical fiber based sensing has now moved from laboratory demonstrations to actual applications in the real world. This has necessitated an entirely new area of extrusion - the packaging (cabling) of optical fibers and sensor arrays to protect them from the intended environment and installation handling while not masking or attenuating the phenomenon that is being sensed. Although each application presents new and unique challenges, the goal is to create a packaging concept for fiber sensors. Fiber sensing applications can be narrowed down to the five items below: 1. Conventional cable packages 2. Assembled (typically by hand) discrete sensor packages 3. Package enhanced sensors (where the packaging improves the effect of the sensor) 4. Linear sensor installation packaging 5. Scalar packaging (where the cabling adds to the range of the sensor) The above applications can be accomplished in a number of ways, and methods are still being developed in this relatively new science. Some of the new technology methods being explored include: UV cured liquids; Voided space cores; Conventional cable extrusion & its determination of mechanical characteristics. This paper reviews the pluses and minuses of the above methods and how their combination ultimately determines how the fiber or sensor array is to be jacketed in order to meet the specific application requirements. This paper will also review non-standard material characteristics, strength members and their role in measuring strain and stress values along with the overall influence of packaging on optical fibers and sensor arrays.

Imaging the atmosphere using volcanic infrasound recorded on a dense local sensor network

NASA Astrophysics Data System (ADS)

Marcillo, O. E.; Johnson, J. B.; Johnson, R.

2010-12-01

We deployed a 47-node infrasound sensor network around Kilauea’s Halemaumau Vent to image the atmospheric conditions of the near-surface. This active vent is a persistent radiator of energetic infrasound enabling us to probe atmospheric winds and temperatures. This research builds upon a previous experiment that recorded infrasound on a three-node network, to determine relative phase delay and invert for atmospheric wind. The technique developed for this previous analysis assumed the intrinsic sound speed and was able to track the evolution of the average wind field in a large area (around 10 km2) and was largely insensitive to local meteorological effects, caused by topography and vegetation. The results of this previous experiment showed the potential of this technique for atmospheric studies and called for a following experiment with a denser sensor network over a larger area. During the summer 2010, we returned to Kilauea and deployed a 47-sensor network in three different configurations around Kilauea summit and down the volcano’s flanks. Persistent infrasonic tremor was ‘loud’ with excess pressures up to 10 Pa (when scaled to 1 km) and periods of high acoustic emissions that lasted from hours to days. The instrumentation for this experiment was composed of single-channel RefTek RT125A Texan digitizers and InfraNMT infrasound sensors. The Texan digitizers provide high-resolution 24-bit analog to digital conversion and can operate continuously for approximately five days with two D-cell batteries. The InfraNMT sensor is based on a piezo-electric transducer and was developed at the Infrasound Laboratory at New Mexico Tech. This sensor features low power (< 3 mA at 9 V) and flat response between 0.02 to 50 Hz. Three different network topologies were tested during this two-week experiment. For the first and second topologies, the sensors were deployed along established roads on two almost perpendicular sensor lines centered at the Halema’uma’u crater. The furthest sensors were located at ~24 km and ~10 km from the vent respectively. Numerical analysis indicates that these two configurations will be able to probe the atmospheric conditions up to 2 km above the ground. The third topology featured most of the sensors on the summit crater at similar radial distances (2-4 km) and different azimuths. The data collected with the third topology is expected to provide detailed information of the very-local infrasonic field. Each configuration was on the ground and operational for around 84 hours. This full dataset will provide an opportunity to investigate source phenomenology and/or propagation effects of the infrasonic field. Tomographic studies of the atmosphere are expected to provide meteorological data that will be of value for ash and gas propagation models.

Collecting and distributing wearable sensor data: an embedded personal area network to local area network gateway server.

PubMed

Neuhaeuser, Jakob; D'Angelo, Lorenzo T

2013-01-01

The goal of the concept and of the device presented in this contribution is to be able to collect sensor data from wearable sensors directly, automatically and wirelessly and to make them available over a wired local area network. Several concepts in e-health and telemedicine make use of portable and wearable sensors to collect movement or activity data. Usually these data are either collected via a wireless personal area network or using a connection to the user's smartphone. However, users might not carry smartphones on them while inside a residential building such as a nursing home or a hospital, but also within their home. Also, in such areas the use of other wireless communication technologies might be limited. The presented system is an embedded server which can be deployed in several rooms in order to ensure live data collection in bigger buildings. Also, the collection of data batches recorded out of range, as soon as a connection is established, is also possible. Both, the system concept and the realization are presented.

Toward one Giga frames per second--evolution of in situ storage image sensors.

PubMed

Etoh, Takeharu G; Son, Dao V T; Yamada, Tetsuo; Charbon, Edoardo

2013-04-08

The ISIS is an ultra-fast image sensor with in-pixel storage. The evolution of the ISIS in the past and in the near future is reviewed and forecasted. To cover the storage area with a light shield, the conventional frontside illuminated ISIS has a limited fill factor. To achieve higher sensitivity, a BSI ISIS was developed. To avoid direct intrusion of light and migration of signal electrons to the storage area on the frontside, a cross-sectional sensor structure with thick pnpn layers was developed, and named "Tetratified structure". By folding and looping in-pixel storage CCDs, an image signal accumulation sensor, ISAS, is proposed. The ISAS has a new function, the in-pixel signal accumulation, in addition to the ultra-high-speed imaging. To achieve much higher frame rate, a multi-collection-gate (MCG) BSI image sensor architecture is proposed. The photoreceptive area forms a honeycomb-like shape. Performance of a hexagonal CCD-type MCG BSI sensor is examined by simulations. The highest frame rate is theoretically more than 1Gfps. For the near future, a stacked hybrid CCD/CMOS MCG image sensor seems most promising. The associated problems are discussed. A fine TSV process is the key technology to realize the structure.

Synthesis and Applications of Large Area Graphene-Based Electrode Systems

NASA Astrophysics Data System (ADS)

Paul, Rajat Kanti

Graphene is a single sheet of carbon atoms with outstanding electrical and physical properties and being exploited for applications in electronics, sensors, fuel cells, photovoltaics and energy storage. However, practical designs of graphene-based electrode systems and related experimental implementations are required to realize their widespread applications in nano- to bioelectronics. In this dissertation, different graphene-based electrode systems having metallic and semiconducting properties are synthesized optimizing process conditions. Also realized is the potential of the fabricated electrode systems by applying them in practical applications such as sensor devices and fuel cells. The zero bandgap of semimetal graphene still limits its application as an effective field-effect transistor device or a chemiresistor sensor operating at room temperature. It has been shown theoretically and experimentally that graphene nanoribbons (GNRs) or nanomeshes (GNMs) can attain a bandgap that is large enough for a transistor device, and hence would show high sensitivity to various gaseous species or biomolecules. Large-area mono- and bilayer graphene films are synthesized by a simple chemical vapor deposition (CVD) technique depending on the carbon precursors such as methane, acetylene and ethanol, and the results are compared using optical microscopy (OM), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM) and x-ray photoelectron spectroscopy (XPS). A simple reactive ion etching (RIE) combined with well-established nanosphere lithography is performed on the synthesized CVD-grown monolayer graphene platform to fabricate large area GNMs with specific dimension and periodicity. The fabricated GNMs chemiresistor sensor devices show excellent sensitivity towards NO2 and NH 3, significantly higher than their film counterparts. The GNM sensor devices exhibit sensitivities of about 4.32%/ppm (parts-per-million) in NO 2 and 0.71%/ppm in NH3 with estimated limit of detections of 15 ppb (parts-per billion) and 160 ppb, significantly lower than Occupational Safety and Health Administration (OSHA) permissible exposure limits of 5 ppm (NO2) and 50 ppm (NH3), respectively. The demonstrated studies on the sensing properties of graphene nanomesh would essentially lead further improvement of it's sensitivity and selectivity as a potential sensor material. Furthermore, a three-dimensional (3D) carbon electrode in the form of vertically aligned carbon nanotubes (CNTs) on a graphene floor is applied as a supporting electrode for platinum (Pt) nanoflowers electrocatalysts in methanol oxidation as well as in nonenzymatic sensing of blood glucose. Experimental results demonstrate an enhanced efficiency of the 3D graphene-carbon nanotubes hybrid film, as catalyst support, for methanol oxidation with regard to electroactive surface area, forward anodic peak current density, onset oxidation potential, diffusion efficiency and the ratio of forward to backward anodic peak current density (If/Ib). Also, the developed nonenzymatic 3D carbon hybrid sensor responded linearly to the physiological glucose concentration ranging from 1 to 7 mM (R2 = 0.978) with a sensitivity of 11.06 muA mM-1cm-2.

Sensor technology workshop: Structure and goals

NASA Technical Reports Server (NTRS)

Wilson, Barbara A.

1991-01-01

The Astrotech 21 charter for the second of three workshops is described. The purpose was to identify technology needs in the areas of electromagnetic radiation sensors, and to recommend a plan to develop the required capabilities that are not currently available. The panels chosen for this workshop focused specifically on those technologies needed for the Astrotech 21 Program including: gamma ray and x ray sensors, ultraviolet and visible sensors, direct infrared sensors, and heterodyne submillimeter wave sensors.

Long-term Acoustic Real-Time Sensor for Polar Areas (LARA)

DTIC Science & Technology

2013-09-30

Volcano and the Middle Valley Ridge segment in the northeast Pacific Ocean. Both areas have seafloor volcanic eruptions forecast for the near future...Sensor for Polar Areas (LARA) for real-time monitoring of marine mammals, ambient noise levels, seismic activities (e.g., eruption of undersea volcanoes...LARA technology will be useful for real-time monitoring of deep-ocean seismic and volcanic activity (e.g., Dziak et al., 2011) - especially in areas

A Method to have Multi-Layer Thermal Insulation Provide Damage Detection

NASA Technical Reports Server (NTRS)

Woodward, Stanley E.; Taylor, Bryant D.; Jones, Thomas W.; Shams, Qamar A.; Lyons, Frankel; Henderson, Donald

2007-01-01

Design and testing of a multi-layer thermal insulation system that also provides debris and micrometeorite damage detection is presented. One layer of the insulation is designed as an array of passive open-circuit electrically conductive spiral trace sensors. The sensors are a new class of sensors that are electrically open-circuits that have no electrical connections thereby eliminating one cause of failure to circuits. The sensors are powered using external oscillating magnetic fields. Once electrically active, they produce their own harmonic magnetic fields. The responding field frequency changes if any sensor is damaged. When the sensors are used together in close proximity, the inductive coupling between sensors provides a means of telemetry. The spiral trace design using reflective electrically conductive material provides sufficient area coverage for the sensor array to serves as a layer of thermal insulation. The other insulation layers are designed to allow the sensor s magnetic field to permeate the insulation layers while having total reflective surface area to reduce thermal energy transfer. Results of characterizing individual sensors and the sensor array s response to punctures are presented. Results of hypervelocity impact testing using projectiles of 1-3.6 millimeter diameter having speeds ranging from 6.7-7.1 kilometers per second are also presented.

Real-time monitoring of ubiquitous wireless ECG sensor node for medical care using ZigBee

NASA Astrophysics Data System (ADS)

Vijayalakshmi, S. R.; Muruganand, S.

2012-01-01

Sensor networks have the potential to impact many aspects of medical care greatly. By outfitting patients with wireless, wearable vital sign sensors, collecting detailed real-time data on physiological status can be greatly simplified. In this article, we propose the system architecture for smart sensor platform based on advanced wireless sensor networks. An emerging application for wireless sensor networks involves their use in medical care. In hospitals or clinics, outfitting every patient with tiny, wearable wireless vital sign sensors would allow doctors, nurses and other caregivers to continuously monitor the status of their patients. In an emergency or disaster scenario, the same technology would enable medics to more effectively care for a large number of casualties. First responders could receive immediate notifications on any changes in patient status, such as respiratory failure or cardiac arrest. Wireless sensor network is a set of small, autonomous devices, working together to solve different problems. It is a relatively new technology, experiencing true expansion in the past decade. People have realised that integration of small and cheap microcontrollers with sensors can result in the production of extremely useful devices, which can be used as an integral part of the sensor nets. These devices are called sensor nodes. Today, sensor nets are used in agriculture, ecology and tourism, but medicine is the area where they certainly meet the greatest potential. This article presents a medical smart sensor node platform. This article proposes a wireless two-lead EKG. These devices collect heart rate and EKG data and relay it over a short-range (300 m) wireless network to any number of receiving devices, including PDAs, laptops or ambulance-based terminals.

Tracking the Effect of Cathodal Transcranial Direct Current Stimulation on Cortical Excitability and Connectivity by Means of TMS-EEG

PubMed Central

Varoli, Erica; Pisoni, Alberto; Mattavelli, Giulia C.; Vergallito, Alessandra; Gallucci, Alessia; Mauro, Lilia D.; Rosanova, Mario; Bolognini, Nadia; Vallar, Giuseppe; Romero Lauro, Leonor J.

2018-01-01

Transcranial direct current stimulation (tDCS) is increasingly used in both research and therapeutic settings, but its precise mechanisms remain largely unknown. At a neuronal level, tDCS modulates cortical excitability by shifting the resting membrane potential in a polarity-dependent way: anodal stimulation increases the spontaneous firing rate, while cathodal decreases it. However, the neurophysiological underpinnings of anodal/cathodal tDCS seem to be different, as well as their behavioral effect, in particular when high order areas are involved, compared to when motor or sensory brain areas are targeted. Previously, we investigated the effect of anodal tDCS on cortical excitability, by means of a combination of Transcranial Magnetic Stimulation (TMS) and Electroencephalography (EEG). Results showed a diffuse rise of cortical excitability in a bilateral fronto-parietal network. In the present study, we tested, with the same paradigm, the effect of cathodal tDCS. Single pulse TMS was delivered over the left posterior parietal cortex (PPC), before, during, and after 10 min of cathodal or sham tDCS over the right PPC, while recording HD-EEG. Indexes of global and local cortical excitability were obtained both at sensors and cortical sources level. At sensors, global and local mean field power (GMFP and LMFP) were computed for three temporal windows (0–50, 50–100, and 100–150 ms), on all channels (GMFP), and in four different clusters of electrodes (LMFP, left and right, in frontal and parietal regions). After source reconstruction, Significant Current Density was computed at the global level, and for four Broadmann's areas (left/right BA 6 and 7). Both sensors and cortical sources results converge in showing no differences during and after cathodal tDCS compared to pre-stimulation sessions, both at global and local level. The same holds for sham tDCS. These data highlight an asymmetric impact of anodal and cathodal stimulation on cortical excitability, with a diffuse effect of anodal and no effect of cathodal tDCS over the parietal cortex. These results are consistent with the current literature: while anodal-excitatory and cathodal-inhibitory effects are well-established in the sensory and motor domains, both at physiological and behavioral levels, results for cathodal stimulation are more controversial for modulation of exitability of higher order areas. PMID:29867330

Predicting risk of invasive species occurrence - remote-sesning strategies

USDA-ARS?s Scientific Manuscript database

Remote sensing is a means to describe characteristics of an area without physically sampling the area. Remote sensors can be mounted on a satellite, plane, or other airborne structure. Remotely sensed data allow for landscape perspectives on management issues. Sensors measure the electromagnetic ene...

A small, lightweight multipollutant sensor system for ground-mobile and aerial emission sampling from open area sources

EPA Science Inventory

Characterizing highly dynamic, transient, and vertically lofted emissions from open area sources poses unique measurement challenges. This study developed and applied a multipollutant sensor and integrated sampler system for use on mobile applications including tethered balloons ...

Analysis of Multi-Scale Radiometric Data Collected during the Cold Land Processes Experiment-1 (CLPX-1)

NASA Technical Reports Server (NTRS)

Tedesco, M.; Kim, E. J.; Gasiewski, A.; Stankov, B.

2005-01-01

Brightness temperature maps at 18.7 and 37 GHz collected at the Fraser and North Park Meso-Scale Areas during the Cold Land Processes Experiment by the NOAA Polarimetric Scanning Radiometer (PSWA) airborne sensor are analyzed. The Fraser site is mostly covered by forest with a typical snowpack depth of 1 m while North Park has no forest cover and is characterized by patches of shallow snow. We examine histograms of the brightness temperatures at 500 m resolution for both the Fraser and North Park areas. The histograms can be modelled by a log-normal distribution in the case of the Fraser MSA and by a bi-modal distribution in the case of the North Park MSA. The histograms of the brightness temperatures at coarser resolutions are also plotted to study the effects of sensor resolution on the shape of the distribution, on the values of the average brightness temperatures and standard deviations. Finally, the values of brightness temperatures obtained by re-sampling (aggregating) the data at 25 km resolution are compared with the values of the brightness temperatures collected by the Advanced Microwave Scanning Radiometer (AMSR-E) and Special Sensor Microwave/Imager (SSMII) satellite radiometers. The results show that in both areas for sensor footprint larger than 5000 m, the brightness temperatures show a flat distribution and the memory of the initial distribution is lost. The values of the brightness temperatures measured by the satellite radiometers are in good agreement with the values obtained averaging the airborne data, even if some discrepancies occur.

A multi-sensor land mine detection system: hardware and architectural outline of the Australian RRAMNS CTD system

NASA Astrophysics Data System (ADS)

Abeynayake, Canicious; Chant, Ian; Kempinger, Siegfried; Rye, Alan

2005-06-01

The Rapid Route Area and Mine Neutralisation System (RRAMNS) Capability Technology Demonstrator (CTD) is a countermine detection project undertaken by DSTO and supported by the Australian Defence Force (ADF). The limited time and budget for this CTD resulted in some difficult strategic decisions with regard to hardware selection and system architecture. Although the delivered system has certain limitations arising from its experimental status, many lessons have been learned which illustrate a pragmatic path for future development. RRAMNS a similar sensor suite to other systems, in that three complementary sensors are included. These are Ground Probing Radar, Metal Detector Array, and multi-band electro-optic sensors. However, RRAMNS uses a unique imaging system and a network based real-time control and sensor fusion architecture. The relatively simple integration of each of these components could be the basis for a robust and cost-effective operational system. The RRAMNS imaging system consists of three cameras which cover the visible spectrum, the mid-wave and long-wave infrared region. This subsystem can be used separately as a scouting sensor. This paper describes the system at its mid-2004 status, when full integration of all detection components was achieved.

Deployment-based lifetime optimization model for homogeneous Wireless Sensor Network under retransmission.

PubMed

Li, Ruiying; Liu, Xiaoxi; Xie, Wei; Huang, Ning

2014-12-10

Sensor-deployment-based lifetime optimization is one of the most effective methods used to prolong the lifetime of Wireless Sensor Network (WSN) by reducing the distance-sensitive energy consumption. In this paper, data retransmission, a major consumption factor that is usually neglected in the previous work, is considered. For a homogeneous WSN, monitoring a circular target area with a centered base station, a sensor deployment model based on regular hexagonal grids is analyzed. To maximize the WSN lifetime, optimization models for both uniform and non-uniform deployment schemes are proposed by constraining on coverage, connectivity and success transmission rate. Based on the data transmission analysis in a data gathering cycle, the WSN lifetime in the model can be obtained through quantifying the energy consumption at each sensor location. The results of case studies show that it is meaningful to consider data retransmission in the lifetime optimization. In particular, our investigations indicate that, with the same lifetime requirement, the number of sensors needed in a non-uniform topology is much less than that in a uniform one. Finally, compared with a random scheme, simulation results further verify the advantage of our deployment model.

Detection of heavy metal ions in drinking water using a high-resolution differential surface plasmon resonance sensor.

PubMed

Forzani, Erica S; Zhang, Haiqian; Chen, Wilfred; Tao, Nongjian

2005-03-01

We have built a high-resolution differential surface plasmon resonance (SPR) sensor for heavy metal ion detection. The sensor surface is divided into a reference and sensing areas, and the difference in the SPR angles from the two areas is detected with a quadrant cell photodetector as a differential signal. In the presence of metal ions, the differential signal changes due to specific binding of the metal ions onto the sensing area coated with properly selected peptides, which provides an accurate real-time measurement and quantification of the metal ions. Selective detection of Cu2+ and Ni2+ in the ppt-ppb range was achieved by coating the sensing surface with peptides NH2-Gly-Gly-His-COOH and NH2-(His)6-COOH. Cu2+ in drinking water was tested using this sensor.

Low cost, multiscale and multi-sensor application for flooded area mapping

NASA Astrophysics Data System (ADS)

Giordan, Daniele; Notti, Davide; Villa, Alfredo; Zucca, Francesco; Calò, Fabiana; Pepe, Antonio; Dutto, Furio; Pari, Paolo; Baldo, Marco; Allasia, Paolo

2018-05-01

Flood mapping and estimation of the maximum water depth are essential elements for the first damage evaluation, civil protection intervention planning and detection of areas where remediation is needed. In this work, we present and discuss a methodology for mapping and quantifying flood severity over floodplains. The proposed methodology considers a multiscale and multi-sensor approach using free or low-cost data and sensors. We applied this method to the November 2016 Piedmont (northwestern Italy) flood. We first mapped the flooded areas at the basin scale using free satellite data from low- to medium-high-resolution from both the SAR (Sentinel-1, COSMO-Skymed) and multispectral sensors (MODIS, Sentinel-2). Using very- and ultra-high-resolution images from the low-cost aerial platform and remotely piloted aerial system, we refined the flooded zone and detected the most damaged sector. The presented method considers both urbanised and non-urbanised areas. Nadiral images have several limitations, in particular in urbanised areas, where the use of terrestrial images solved this limitation. Very- and ultra-high-resolution images were processed with structure from motion (SfM) for the realisation of 3-D models. These data, combined with an available digital terrain model, allowed us to obtain maps of the flooded area, maximum high water area and damaged infrastructures.

Reconstruction of in-plane strain maps using hybrid dense sensor network composed of sensing skin

NASA Astrophysics Data System (ADS)

Downey, Austin; Laflamme, Simon; Ubertini, Filippo

2016-12-01

The authors have recently developed a soft-elastomeric capacitive (SEC)-based thin film sensor for monitoring strain on mesosurfaces. Arranged in a network configuration, the sensing system is analogous to a biological skin, where local strain can be monitored over a global area. Under plane stress conditions, the sensor output contains the additive measurement of the two principal strain components over the monitored surface. In applications where the evaluation of strain maps is useful, in structural health monitoring for instance, such signal must be decomposed into linear strain components along orthogonal directions. Previous work has led to an algorithm that enabled such decomposition by leveraging a dense sensor network configuration with the addition of assumed boundary conditions. Here, we significantly improve the algorithm’s accuracy by leveraging mature off-the-shelf solutions to create a hybrid dense sensor network (HDSN) to improve on the boundary condition assumptions. The system’s boundary conditions are enforced using unidirectional RSGs and assumed virtual sensors. Results from an extensive experimental investigation demonstrate the good performance of the proposed algorithm and its robustness with respect to sensors’ layout. Overall, the proposed algorithm is seen to effectively leverage the advantages of a hybrid dense network for application of the thin film sensor to reconstruct surface strain fields over large surfaces.

Automatic Multi-sensor Data Quality Checking and Event Detection for Environmental Sensing

NASA Astrophysics Data System (ADS)

LIU, Q.; Zhang, Y.; Zhao, Y.; Gao, D.; Gallaher, D. W.; Lv, Q.; Shang, L.

2017-12-01

With the advances in sensing technologies, large-scale environmental sensing infrastructures are pervasively deployed to continuously collect data for various research and application fields, such as air quality study and weather condition monitoring. In such infrastructures, many sensor nodes are distributed in a specific area and each individual sensor node is capable of measuring several parameters (e.g., humidity, temperature, and pressure), providing massive data for natural event detection and analysis. However, due to the dynamics of the ambient environment, sensor data can be contaminated by errors or noise. Thus, data quality is still a primary concern for scientists before drawing any reliable scientific conclusions. To help researchers identify potential data quality issues and detect meaningful natural events, this work proposes a novel algorithm to automatically identify and rank anomalous time windows from multiple sensor data streams. More specifically, (1) the algorithm adaptively learns the characteristics of normal evolving time series and (2) models the spatial-temporal relationship among multiple sensor nodes to infer the anomaly likelihood of a time series window for a particular parameter in a sensor node. Case studies using different data sets are presented and the experimental results demonstrate that the proposed algorithm can effectively identify anomalous time windows, which may resulted from data quality issues and natural events.

Working Group Report: Sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Artuso, M.; et al.,

Sensors play a key role in detecting both charged particles and photons for all three frontiers in Particle Physics. The signals from an individual sensor that can be used include ionization deposited, phonons created, or light emitted from excitations of the material. The individual sensors are then typically arrayed for detection of individual particles or groups of particles. Mounting of new, ever higher performance experiments, often depend on advances in sensors in a range of performance characteristics. These performance metrics can include position resolution for passing particles, time resolution on particles impacting the sensor, and overall rate capabilities. In additionmore » the feasible detector area and cost frequently provides a limit to what can be built and therefore is often another area where improvements are important. Finally, radiation tolerance is becoming a requirement in a broad array of devices. We present a status report on a broad category of sensors, including challenges for the future and work in progress to solve those challenges.« less

Sensor Compendium - A Snowmass Whitepaper-

DOE Office of Scientific and Technical Information (OSTI.GOV)

Artuso, M.; Battaglia, M.; Bolla, G.

Sensors play a key role in detecting both charged particles and photons for all three frontiers in Particle Physics. The signals from an individual sensor that can be used include ionization deposited, phonons created, or light emitted from excitations of the material. The individual sensors are then typically arrayed for detection of individual particles or groups of particles. Mounting of new, ever higher performance experiments, often depend on advances in sensors in a range of performance characteristics. These performance metrics can include position resolution for passing particles, time resolution on particles impacting the sensor, and overall rate capabilities. In additionmore » the feasible detector area and cost frequently provides a limit to what can be built and therefore is often another area where improvements are important. Finally, radiation tolerance is becoming a requirement in a broad array of devices. We present a status report on a broad category of sensors, including challenges for the future and work in progress to solve those challenges.« less

Capacity Building for Research and Education in GIS/GPS Technology and Systems

DTIC Science & Technology

2015-05-20

In multi- sensor area Wireless Sensor Networking (WSN) fields will be explored. As a step forward the research to be conducted in WSN field is to...Agriculture Using Technology for Crops Scouting in Agriculture Application of Technology in Precision Agriculture Wireless Sensor Network (WSN) in...Cooperative Engagement Capability Range based algorithms for Wireless Sensor Network Self-configurable Wireless Sensor Network Energy Efficient Wireless

Multi-Axis Force/Torque Sensor Based on Simply-Supported Beam and Optoelectronics.

PubMed

Noh, Yohan; Bimbo, Joao; Sareh, Sina; Wurdemann, Helge; Fraś, Jan; Chathuranga, Damith Suresh; Liu, Hongbin; Housden, James; Althoefer, Kaspar; Rhode, Kawal

2016-11-17

This paper presents a multi-axis force/torque sensor based on simply-supported beam and optoelectronic technology. The sensor's main advantages are: (1) Low power consumption; (2) low-level noise in comparison with conventional methods of force sensing (e.g., using strain gauges); (3) the ability to be embedded into different mechanical structures; (4) miniaturisation; (5) simple manufacture and customisation to fit a wide-range of robot systems; and (6) low-cost fabrication and assembly of sensor structure. For these reasons, the proposed multi-axis force/torque sensor can be used in a wide range of application areas including medical robotics, manufacturing, and areas involving human-robot interaction. This paper shows the application of our concept of a force/torque sensor to flexible continuum manipulators: A cylindrical MIS (Minimally Invasive Surgery) robot, and includes its design, fabrication, and evaluation tests.

Low Frequency Radar Sensor Observations of Tropical Forests in the Panama Canal Area

NASA Technical Reports Server (NTRS)

Imhoff, M. L.; Lawrence, W.; Condit, R.; Wright, J.; Johnson, P.; Hyer, J.; May, L.; Carson, S.; Smith, David E. (Technical Monitor)

2000-01-01

A synthetic aperture radar sensor operating in 5 bands between 80 and 120 MHz was flown over forested areas in the canal zone of the Republic of Panama in an experiment to measure biomass in heavy tropical forests. The sensor is a pulse coherent SAR flown on a small aircraft and oriented straight down. The doppler history is processed to collect data on the ground in rectangular cells of varying size over a range of incidence angles fore and aft of nadir (+45 to - 45 degrees). Sensor data consists of 5 frequency bands with 20 incidence angles per band. Sensor data for over 12+ sites were collected with forest stands having biomass densities ranging from 50 to 300 tons/ha dry above ground biomass. Results are shown exploring the biomass saturation thresholds using these frequencies, the system design is explained, and preliminary attempts at data visualization using this unique sensor design are described.

Inertial sensor-based methods in walking speed estimation: a systematic review.

PubMed

Yang, Shuozhi; Li, Qingguo

2012-01-01

Self-selected walking speed is an important measure of ambulation ability used in various clinical gait experiments. Inertial sensors, i.e., accelerometers and gyroscopes, have been gradually introduced to estimate walking speed. This research area has attracted a lot of attention for the past two decades, and the trend is continuing due to the improvement of performance and decrease in cost of the miniature inertial sensors. With the intention of understanding the state of the art of current development in this area, a systematic review on the exiting methods was done in the following electronic engines/databases: PubMed, ISI Web of Knowledge, SportDiscus and IEEE Xplore. Sixteen journal articles and papers in proceedings focusing on inertial sensor based walking speed estimation were fully reviewed. The existing methods were categorized by sensor specification, sensor attachment location, experimental design, and walking speed estimation algorithm.

Bioinspired Polarization Imaging Sensors: From Circuits and Optics to Signal Processing Algorithms and Biomedical Applications

PubMed Central

York, Timothy; Powell, Samuel B.; Gao, Shengkui; Kahan, Lindsey; Charanya, Tauseef; Saha, Debajit; Roberts, Nicholas W.; Cronin, Thomas W.; Marshall, Justin; Achilefu, Samuel; Lake, Spencer P.; Raman, Baranidharan; Gruev, Viktor

2015-01-01

In this paper, we present recent work on bioinspired polarization imaging sensors and their applications in biomedicine. In particular, we focus on three different aspects of these sensors. First, we describe the electro–optical challenges in realizing a bioinspired polarization imager, and in particular, we provide a detailed description of a recent low-power complementary metal–oxide–semiconductor (CMOS) polarization imager. Second, we focus on signal processing algorithms tailored for this new class of bioinspired polarization imaging sensors, such as calibration and interpolation. Third, the emergence of these sensors has enabled rapid progress in characterizing polarization signals and environmental parameters in nature, as well as several biomedical areas, such as label-free optical neural recording, dynamic tissue strength analysis, and early diagnosis of flat cancerous lesions in a murine colorectal tumor model. We highlight results obtained from these three areas and discuss future applications for these sensors. PMID:26538682

Inertial Sensor-Based Methods in Walking Speed Estimation: A Systematic Review

PubMed Central

Yang, Shuozhi; Li, Qingguo

2012-01-01

Self-selected walking speed is an important measure of ambulation ability used in various clinical gait experiments. Inertial sensors, i.e., accelerometers and gyroscopes, have been gradually introduced to estimate walking speed. This research area has attracted a lot of attention for the past two decades, and the trend is continuing due to the improvement of performance and decrease in cost of the miniature inertial sensors. With the intention of understanding the state of the art of current development in this area, a systematic review on the exiting methods was done in the following electronic engines/databases: PubMed, ISI Web of Knowledge, SportDiscus and IEEE Xplore. Sixteen journal articles and papers in proceedings focusing on inertial sensor based walking speed estimation were fully reviewed. The existing methods were categorized by sensor specification, sensor attachment location, experimental design, and walking speed estimation algorithm. PMID:22778632

Sensor Networks in the Low Lands

PubMed Central

Meratnia, Nirvana; van der Zwaag, Berend Jan; van Dijk, Hylke W.; Bijwaard, Dennis J. A.; Havinga, Paul J. M.

2010-01-01

This paper provides an overview of scientific and industrial developments of the last decade in the area of sensor networks in The Netherlands (Low Lands). The goal is to highlight areas in which the Netherlands has made most contributions and is currently a dominant player in the field of sensor networks. On the one hand, motivations, addressed topics, and initiatives taken in this period are presented, while on the other hand, special emphasis is given to identifying current and future trends and formulating a vision for the coming five to ten years. The presented overview and trend analysis clearly show that Dutch research and industrial efforts, in line with recent worldwide developments in the field of sensor technology, present a clear shift from sensor node platforms, operating systems, communication, networking, and data management aspects of the sensor networks to reasoning/cognition, control, and actuation. PMID:22163669

Design of Weft Detection System in The Stenter Machine

NASA Astrophysics Data System (ADS)

Gu, Minming; Xu, Xianju; Dai, Wenzhan

2017-12-01

In order to build an effective automatic weft-straightening system, it is important for the sensing device to detect most the possible fabric styles, designs, colours and structures, an optical sensing system that detects the angular orientation of weft threads in a moving web of a textile has been built. It contains an adjustable light source, two lens systems and photodiode sensor array. The sensor array includes 13 radial pattern of photosensitive areas that each generate an electrical signal proportional to the total intensity of the light incident on the area. The moving shadow of a weft thread passing over the area will modulate the output signal. A signal processed circuit was built to do the I/V conversion, amplifying, hardware filtering. An embed micro control system then deals with the information of these signals, calculates the angle of the weft drew. Finally, the experiments were done, the results showed that the weft detection system can deal with the fabric weft skew up to 30° and has achieved good results in the application.

Novel Kalman Filter Algorithm for Statistical Monitoring of Extensive Landscapes with Synoptic Sensor Data

PubMed Central

Czaplewski, Raymond L.

2015-01-01

Wall-to-wall remotely sensed data are increasingly available to monitor landscape dynamics over large geographic areas. However, statistical monitoring programs that use post-stratification cannot fully utilize those sensor data. The Kalman filter (KF) is an alternative statistical estimator. I develop a new KF algorithm that is numerically robust with large numbers of study variables and auxiliary sensor variables. A National Forest Inventory (NFI) illustrates application within an official statistics program. Practical recommendations regarding remote sensing and statistical issues are offered. This algorithm has the potential to increase the value of synoptic sensor data for statistical monitoring of large geographic areas. PMID:26393588

Applications of artificial intelligence to space station: General purpose intelligent sensor interface

NASA Technical Reports Server (NTRS)

Mckee, James W.

1988-01-01

This final report describes the accomplishments of the General Purpose Intelligent Sensor Interface task of the Applications of Artificial Intelligence to Space Station grant for the period from October 1, 1987 through September 30, 1988. Portions of the First Biannual Report not revised will not be included but only referenced. The goal is to develop an intelligent sensor system that will simplify the design and development of expert systems using sensors of the physical phenomena as a source of data. This research will concentrate on the integration of image processing sensors and voice processing sensors with a computer designed for expert system development. The result of this research will be the design and documentation of a system in which the user will not need to be an expert in such areas as image processing algorithms, local area networks, image processor hardware selection or interfacing, television camera selection, voice recognition hardware selection, or analog signal processing. The user will be able to access data from video or voice sensors through standard LISP statements without any need to know about the sensor hardware or software.

Polyacrylonitrile nanofiber as polar solvent N,N-dimethyl formamide sensor based on quartz crystal microbalance technique

NASA Astrophysics Data System (ADS)

Rianjanu, A.; Julian, T.; Hidayat, S. N.; Suyono, E. A.; Kusumaatmaja, A.; Triyana, K.

2018-04-01

Here, we describe an N,N-dimethyl formamide (DMF) vapour sensor fabricated by coating polyacrylonitrile (PAN) nanofiber structured on quartz crystal microbalance (QCM). The PAN nanofiber sensors with an average diameter of 225 nm to 310 nm were fabricated via electrospinning process with different mass deposition on QCM substrate. The nanostructured of PAN nanofiber offers a high specific surface area that improved the sensing performance of nanofiber sensors. Benefiting from that fine structure, and high polymer-solvent affinity between PAN and DMF, the development of DMF sensors presented good response at ambient temperature. Since there is no chemical reaction between PAN nanofiber and DMF vapour, weak physical interaction such absorption and swelling were responsible for the sensing behavior. The results are indicating that the response of PAN nanofiber sensors has more dependency on the nanofiber structure (specific surface area) rather than its mass deposition. The sensor also showed good stability after a few days sensing. These findings have significant implications for developing DMF vapour sensor based on QCM coated polymer nanofibers.

Cost effective spectral sensor solutions for hand held and field applications

NASA Astrophysics Data System (ADS)

Reetz, Edgar; Correns, Martin; Notni, Gunther

2015-05-01

Optical spectroscopy is without doubt one of the most important non-contact measurement principles. It is used in a wide range of applications from bio-medical to industrial fields. One recent trend is to miniaturize spectral sensors to address new areas of application. The most common spectral sensor type is based on diffraction gratings, while other types are based on micro mechanical systems (MEMS) or filter technologies. The authors represent the opinion that there is a potentially wide spread field of applications for spectrometers, but the market limits the range of applications since they cannot keep up with targeted cost requirements for consumer products. The present article explains an alternative approach for miniature multichannel spectrometer to enhance robustness for hand held field applications at a cost efficient price point.

Using a plenoptic sensor to reconstruct vortex phase structures.

PubMed

Wu, Chensheng; Ko, Jonathan; Davis, Christopher C

2016-07-15

A branch point problem and its solution commonly involve recognizing and reconstructing a vortex phase structure around a singular point. In laser beam propagation through random media, the destructive phase contributions from various parts of a vortex phase structure will cause a dark area in the center of the beam's intensity profile. This null of intensity can, in turn, prevent the vortex phase structure from being recognized. In this Letter, we show how to use a plenoptic sensor to transform the light field of a vortex beam so that a simple and direct reconstruction algorithm can be applied to reveal the vortex phase structure. As a result, we show that the plenoptic sensor is effective in detecting branch points and can be used to reconstruct phase distortion in a beam in a wide sense.

Intelligent Wireless Sensor Networks for System Health Monitoring

NASA Technical Reports Server (NTRS)

Alena, Rick

2011-01-01

Wireless sensor networks (WSN) based on the IEEE 802.15.4 Personal Area Network (PAN) standard are finding increasing use in the home automation and emerging smart energy markets. The network and application layers, based on the ZigBee 2007 Standard, provide a convenient framework for component-based software that supports customer solutions from multiple vendors. WSNs provide the inherent fault tolerance required for aerospace applications. The Discovery and Systems Health Group at NASA Ames Research Center has been developing WSN technology for use aboard aircraft and spacecraft for System Health Monitoring of structures and life support systems using funding from the NASA Engineering and Safety Center and Exploration Technology Development and Demonstration Program. This technology provides key advantages for low-power, low-cost ancillary sensing systems particularly across pressure interfaces and in areas where it is difficult to run wires. Intelligence for sensor networks could be defined as the capability of forming dynamic sensor networks, allowing high-level application software to identify and address any sensor that joined the network without the use of any centralized database defining the sensors characteristics. The IEEE 1451 Standard defines methods for the management of intelligent sensor systems and the IEEE 1451.4 section defines Transducer Electronic Datasheets (TEDS), which contain key information regarding the sensor characteristics such as name, description, serial number, calibration information and user information such as location within a vehicle. By locating the TEDS information on the wireless sensor itself and enabling access to this information base from the application software, the application can identify the sensor unambiguously and interpret and present the sensor data stream without reference to any other information. The application software is able to read the status of each sensor module, responding in real-time to changes of PAN configuration, providing the appropriate response for maintaining overall sensor system function, even when sensor modules fail or the WSN is reconfigured. The session will present the architecture and technical feasibility of creating fault-tolerant WSNs for aerospace applications based on our application of the technology to a Structural Health Monitoring testbed. The interim results of WSN development and testing including our software architecture for intelligent sensor management will be discussed in the context of the specific tradeoffs required for effective use. Initial certification measurement techniques and test results gauging WSN susceptibility to Radio Frequency interference are introduced as key challenges for technology adoption. A candidate Developmental and Flight Instrumentation implementation using intelligent sensor networks for wind tunnel and flight tests is developed as a guide to understanding key aspects of the aerospace vehicle design, test and operations life cycle.

Design of autonomous sensor nodes for remote soil monitoring in tropical banana plantation

NASA Astrophysics Data System (ADS)

Tiausas, Francis Jerome G.; Co, Jerelyn; Macalinao, Marc Joseph M.; Guico, Maria Leonora; Monje, Jose Claro; Oppus, Carlos

2017-09-01

Determining the effect of Fusarium oxysporum f. sp. cubense Tropical Race 4 on various soil parameters is essential in modeling and predicting its occurrence in banana plantations. One way to fulfill this is through a sensor network that will continuously and automatically monitor environmental conditions at suspect locations for an extended period of time. A wireless sensor network was developed specifically for this purpose. This sensor network is capable of measuring soil acidity, moisture, temperature, and conductivity. The designed prototype made use of off-the-shelf Parrot Flower Power soil sensor, pH sensor, Bluno Beetle, battery, and 3D-printed materials, catering specifically to the conditions of tropical banana plantations with consideration for sensor node size, communication, and power. Sensor nodes were tested on both simulated tropical environments and on an actual banana plantation in San Jose, General Santos City, Philippines. Challenges were resolved through iterative design and development of prototypes. Several tests including temperature and weather resilience, and structural stress tests were done to validate the design. Findings showed that the WSN nodes developed for this purpose are resilient to high tropical temperatures for up to 12 hours of continuous exposure, are able to withstand compressive forces of up to 8880.6 N, and can reliably collect data automatically from the area 47.96% of the time at an hourly frequency under actual field conditions.

Real-time, wide-area hyperspectral imaging sensors for standoff detection of explosives and chemical warfare agents

NASA Astrophysics Data System (ADS)

Gomer, Nathaniel R.; Tazik, Shawna; Gardner, Charles W.; Nelson, Matthew P.

2017-05-01

Hyperspectral imaging (HSI) is a valuable tool for the detection and analysis of targets located within complex backgrounds. HSI can detect threat materials on environmental surfaces, where the concentration of the target of interest is often very low and is typically found within complex scenery. Unfortunately, current generation HSI systems have size, weight, and power limitations that prohibit their use for field-portable and/or real-time applications. Current generation systems commonly provide an inefficient area search rate, require close proximity to the target for screening, and/or are not capable of making real-time measurements. ChemImage Sensor Systems (CISS) is developing a variety of real-time, wide-field hyperspectral imaging systems that utilize shortwave infrared (SWIR) absorption and Raman spectroscopy. SWIR HSI sensors provide wide-area imagery with at or near real time detection speeds. Raman HSI sensors are being developed to overcome two obstacles present in standard Raman detection systems: slow area search rate (due to small laser spot sizes) and lack of eye-safety. SWIR HSI sensors have been integrated into mobile, robot based platforms and handheld variants for the detection of explosives and chemical warfare agents (CWAs). In addition, the fusion of these two technologies into a single system has shown the feasibility of using both techniques concurrently to provide higher probability of detection and lower false alarm rates. This paper will provide background on Raman and SWIR HSI, discuss the applications for these techniques, and provide an overview of novel CISS HSI sensors focusing on sensor design and detection results.

Miniaturized pH Sensors Based on Zinc Oxide Nanotubes/Nanorods

PubMed Central

Fulati, Alimujiang; Ali, Syed M.Usman; Riaz, Muhammad; Amin, Gul; Nur, Omer; Willander, Magnus

2009-01-01

ZnO nanotubes and nanorods grown on gold thin film were used to create pH sensor devices. The developed ZnO nanotube and nanorod pH sensors display good reproducibility, repeatability and long-term stability and exhibit a pH-dependent electrochemical potential difference versus an Ag/AgCl reference electrode over a large dynamic pH range. We found the ZnO nanotubes provide sensitivity as high as twice that of the ZnO nanorods, which can be ascribed to the fact that small dimensional ZnO nanotubes have a higher level of surface and subsurface oxygen vacancies and provide a larger effective surface area with higher surface-to-volume ratio as compared to ZnO nanorods, thus affording the ZnO nanotube pH sensor a higher sensitivity. Experimental results indicate ZnO nanotubes can be used in pH sensor applications with improved performance. Moreover, the ZnO nanotube arrays may find potential application as a novel material for measurements of intracellular biochemical species within single living cells. PMID:22291545

Visual gas sensors based on dye thin films and resonant waveguide gratings

NASA Astrophysics Data System (ADS)

Davoine, L.; Schnieper, M.; Barranco, A.; Aparicio, F. J.

2011-05-01

A colorimetric sensor that provides a direct visual indication of chemical contamination was developed. The detection is based on the color change of the reflected light after exposure to a gas or a liquid. The sensor is a combination of a chemically sensitive dye layer and a subwavelength grating structure. To enhance the perception of color change, a reference area sealed under a non-contaminated atmosphere is used and placed next to the sensor. The color change is clearly visible by human eyes. The device is based on photonic resonant effects; the visible color is a direct reflection of some incoming light, therefore no additional supplies are needed. This makes it usable as a standalone disposable sensor. The dye thin film is deposited by Plasma enhanced chemical vapor deposition (PECVD) on top of the subwavelength structure. The latter is made by combining a replication process of a Sol-Gel material and a thin film deposition. Lowcost fabrication and compatibility with environments where electricity cannot be used make this device very attractive for applications in hospitals, industries, with explosives and in traffic.

Stretchable Electronic Sensors of Nanocomposite Network Films for Ultrasensitive Chemical Vapor Sensing.

PubMed

Yan, Hong; Zhong, Mengjuan; Lv, Ze; Wan, Pengbo

2017-11-01

A stretchable, transparent, and body-attachable chemical sensor is assembled from the stretchable nanocomposite network film for ultrasensitive chemical vapor sensing. The stretchable nanocomposite network film is fabricated by in situ preparation of polyaniline/MoS 2 (PANI/MoS 2 ) nanocomposite in MoS 2 suspension and simultaneously nanocomposite deposition onto prestrain elastomeric polydimethylsiloxane substrate. The assembled stretchable electronic sensor demonstrates ultrasensitive sensing performance as low as 50 ppb, robust sensing stability, and reliable stretchability for high-performance chemical vapor sensing. The ultrasensitive sensing performance of the stretchable electronic sensors could be ascribed to the synergistic sensing advantages of MoS 2 and PANI, higher specific surface area, the reliable sensing channels of interconnected network, and the effectively exposed sensing materials. It is expected to hold great promise for assembling various flexible stretchable chemical vapor sensors with ultrasensitive sensing performance, superior sensing stability, reliable stretchability, and robust portability to be potentially integrated into wearable electronics for real-time monitoring of environment safety and human healthcare. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Integrated multisensor perimeter detection systems

NASA Astrophysics Data System (ADS)

Kent, P. J.; Fretwell, P.; Barrett, D. J.; Faulkner, D. A.

2007-10-01

The report describes the results of a multi-year programme of research aimed at the development of an integrated multi-sensor perimeter detection system capable of being deployed at an operational site. The research was driven by end user requirements in protective security, particularly in threat detection and assessment, where effective capability was either not available or prohibitively expensive. Novel video analytics have been designed to provide robust detection of pedestrians in clutter while new radar detection and tracking algorithms provide wide area day/night surveillance. A modular integrated architecture based on commercially available components has been developed. A graphical user interface allows intuitive interaction and visualisation with the sensors. The fusion of video, radar and other sensor data provides the basis of a threat detection capability for real life conditions. The system was designed to be modular and extendable in order to accommodate future and legacy surveillance sensors. The current sensor mix includes stereoscopic video cameras, mmWave ground movement radar, CCTV and a commercially available perimeter detection cable. The paper outlines the development of the system and describes the lessons learnt after deployment in a pilot trial.

Community Air Sensor Network (CAIRSENSE) project ...

EPA Pesticide Factsheets

Advances in air pollution sensor technology have enabled the development of small and low cost systems to measure outdoor air pollution. The deployment of a large number of sensors across a small geographic area would have potential benefits to supplement traditional monitoring networks with additional geographic and temporal measurement resolution, if the data quality were sufficient. To understand the capability of emerging air sensor technology, the Community Air Sensor Network (CAIRSENSE) project deployed low cost, continuous and commercially-available air pollution sensors at a regulatory air monitoring site and as a local sensor network over a surrounding ~2 km area in Southeastern U.S. Co-location of sensors measuring oxides of nitrogen, ozone, carbon monoxide, sulfur dioxide, and particles revealed highly variable performance, both in terms of comparison to a reference monitor as well as whether multiple identical sensors reproduced the same signal. Multiple ozone, nitrogen dioxide, and carbon monoxide sensors revealed low to very high correlation with a reference monitor, with Pearson sample correlation coefficient (r) ranging from 0.39 to 0.97, -0.25 to 0.76, -0.40 to 0.82, respectively. The only sulfur dioxide sensor tested revealed no correlation (r 0.5), step-wise multiple linear regression was performed to determine if ambient temperature, relative humidity (RH), or age of the sensor in sampling days could be used in a correction algorihm to im

Synthetic depth data creation for sensor setup planning and evaluation of multi-camera multi-person trackers

NASA Astrophysics Data System (ADS)

Pattke, Marco; Martin, Manuel; Voit, Michael

2017-05-01

Tracking people with cameras in public areas is common today. However with an increasing number of cameras it becomes harder and harder to view the data manually. Especially in safety critical areas automatic image exploitation could help to solve this problem. Setting up such a system can however be difficult because of its increased complexity. Sensor placement is critical to ensure that people are detected and tracked reliably. We try to solve this problem using a simulation framework that is able to simulate different camera setups in the desired environment including animated characters. We combine this framework with our self developed distributed and scalable system for people tracking to test its effectiveness and can show the results of the tracking system in real time in the simulated environment.

Future superconductivity applications in space - A review

NASA Astrophysics Data System (ADS)

Krishen, Kumar; Ignatiev, Alex

High temperature superconductor (HISC) materials and devices can provide immediate applications for many space missions. The in-space thermal environment provides an opportunity to develop, test, and apply this technology to enhance performance and reliability for many applications of crucial importance to NASA. Specifically, the technology development areas include: (1) high current power transmission, (2) microwave components, devices, and antennas, (3) microwave, optical, and infrared sensors, (4) signal processors, (5) submillimeter wave components and systems, (6) ultra stable space clocks, (7) electromagnetic launch systems, and (8) accelerometers and position sensors for flight operations. HTSC is expected to impact NASA's Lunar Bases, Mars exploration, Mission to Earth, and Planetary exploration programs providing enabling and cost-effect technology. A review of the space applications of the HTSC technology is presented. Problem areas in technology development needing special attention are identified.

Electrohydrodynamic inkjet printing of Pd loaded SnO2 nanofibers on a CMOS micro hotplate for low power H2 detection

NASA Astrophysics Data System (ADS)

Wu, Hao; Yu, Jun; Cao, Rui; Yang, Yinghua; Tang, Zhenan

2018-05-01

A high-performance low-power micro hotplate (MHP) hydrogen sensor was fabricated through electrohydrodynamic (EHD) inkjet printing technique. Electrospun Pd loaded SnO2 nanofibers with lengths of 250-850 nm were precisely printed on the suspended central part of an MHP with an area of 100 um × 100 um. The printhead in the printing system was a low-cost metallic needle with an inner diameter of 110 um, which was large enough to prevent clogging by the nanofibers. The printing process was observed by a high-speed camera. Small droplets with diameters of 50-80 um were produced at each ejection by providing a high voltage to the metallic needle. It was found that the bridge-type MHPs used in our experiment can promote the positioning precision due to its bound effect to the droplet. In the gas sensing measurement, the Pd loaded SnO2 MHP gas sensor showed a remarkable response to H2 with a low power of only 9.1 mW. The experiment results demonstrate the excellent adequacy of EHD inkjet printing technique to realize effective mass fabrication of MHP gas sensors or sensor arrays.

Microfabricated sensors for the measurement of electromagnetic fields in biological tissues

NASA Astrophysics Data System (ADS)

Monberg, James; Henning, Albert K.

1995-09-01

Public awareness of the risks of exposure to electromagnetic radiation has grown over the past ten yeras. The effects of power lines on human and animal health have drawn particular attention. Some longitudinal studies of cancer rates near power lines show a significant correlation, while others show a null result. The studies have suffered from inadequate sensors for the measurement of electromagnetic radiation in vivo. In this work, we describe the design, construction, and testing of electrically passive, microfabricated single-pole antennas and coils. These sensors will be used in vivo to study the effects of electromagnetic radiation on animals. Our testing to date has been limited to in vitro studies of the magnetic field probes. Magnetic field pickup coils were fabricated with up to 100 turns, over a length of up to 1000 micrometers . Measurements were carried out with the sensors in air, and in water of various saline concentrations. Magnetic fields were applied using a Helmholtz coil. Both dc and ac fields were applied. The results indicate that small-area measurements of electromagnetic fields in vitro can be made successfully, provided adequate shielding and amplification are used.

Kelvin probe microscopy and electronic transport measurements in reduced graphene oxide chemical sensors

NASA Astrophysics Data System (ADS)

Kehayias, Christopher E.; MacNaughton, Samuel; Sonkusale, Sameer; Staii, Cristian

2013-06-01

Reduced graphene oxide (RGO) is an electronically hybrid material that displays remarkable chemical sensing properties. Here, we present a quantitative analysis of the chemical gating effects in RGO-based chemical sensors. The gas sensing devices are patterned in a field-effect transistor geometry, by dielectrophoretic assembly of RGO platelets between gold electrodes deposited on SiO2/Si substrates. We show that these sensors display highly selective and reversible responses to the measured analytes, as well as fast response and recovery times (tens of seconds). We use combined electronic transport/Kelvin probe microscopy measurements to quantify the amount of charge transferred to RGO due to chemical doping when the device is exposed to electron-acceptor (acetone) and electron-donor (ammonia) analytes. We demonstrate that this method allows us to obtain high-resolution maps of the surface potential and local charge distribution both before and after chemical doping, to identify local gate-susceptible areas on the RGO surface, and to directly extract the contact resistance between the RGO and the metallic electrodes. The method presented is general, suggesting that these results have important implications for building graphene and other nanomaterial-based chemical sensors.

Kelvin probe microscopy and electronic transport measurements in reduced graphene oxide chemical sensors.

PubMed

Kehayias, Christopher E; MacNaughton, Samuel; Sonkusale, Sameer; Staii, Cristian

2013-06-21

Reduced graphene oxide (RGO) is an electronically hybrid material that displays remarkable chemical sensing properties. Here, we present a quantitative analysis of the chemical gating effects in RGO-based chemical sensors. The gas sensing devices are patterned in a field-effect transistor geometry, by dielectrophoretic assembly of RGO platelets between gold electrodes deposited on SiO2/Si substrates. We show that these sensors display highly selective and reversible responses to the measured analytes, as well as fast response and recovery times (tens of seconds). We use combined electronic transport/Kelvin probe microscopy measurements to quantify the amount of charge transferred to RGO due to chemical doping when the device is exposed to electron-acceptor (acetone) and electron-donor (ammonia) analytes. We demonstrate that this method allows us to obtain high-resolution maps of the surface potential and local charge distribution both before and after chemical doping, to identify local gate-susceptible areas on the RGO surface, and to directly extract the contact resistance between the RGO and the metallic electrodes. The method presented is general, suggesting that these results have important implications for building graphene and other nanomaterial-based chemical sensors.

Wafer-scale pixelated detector system

DOEpatents

Fahim, Farah; Deptuch, Grzegorz; Zimmerman, Tom

2017-10-17

A large area, gapless, detection system comprises at least one sensor; an interposer operably connected to the at least one sensor; and at least one application specific integrated circuit operably connected to the sensor via the interposer wherein the detection system provides high dynamic range while maintaining small pixel area and low power dissipation. Thereby the invention provides methods and systems for a wafer-scale gapless and seamless detector systems with small pixels, which have both high dynamic range and low power dissipation.

Bio-implantable passive on-chip RF-MEMS strain sensing resonators for orthopaedic applications

NASA Astrophysics Data System (ADS)

Melik, Rohat; Kosku Perkgoz, Nihan; Unal, Emre; Puttlitz, Christian; Demir, Hilmi Volkan

2008-11-01

One out of ten bone fractures does not heal properly due to improper load distribution and strain profiles during the healing process. To provide implantable tools for the assessment of bone fractures, we have designed novel, bio-implantable, passive, on-chip, RF-MEMS strain sensors that rely on the resonance frequency shift with mechanical deformation. For this purpose, we modeled, fabricated and experimentally characterized two on-chip sensors with high quality factors for in vivo implantation. One of the sensors has an area of ~0.12 mm2 with a quality factor of ~60 and the other has an area of ~0.07 mm2 with a quality factor of ~70. To monitor the mechanical deformation by measuring the change in the resonance frequencies with the applied load, we employed a controllable, point load applying experimental setup designed and constructed for in vitro characterization. In the case of the sensor with the larger area, when we apply a load of 3920 N, we obtain a frequency shift of ~330 MHz and a quality factor of ~76. For the smaller sensor, the frequency shift and the quality factor are increased to 360 MHz and 95, respectively. These data demonstrate that our sensor chips have the capacity to withstand relatively high physiologic loads, and that the concomitant and very large resonant frequency shift with the applied load is achieved while maintaining a high signal quality factor. These experiments demonstrate that these novel sensors have the capacity for producing high sensitivity strain readout, even when the total device area is considerably small. Also, we have demonstrated that our bio-implantable, passive sensors deliver a telemetric, real-time readout of the strain on a chip. Placing two more resonators on the sides of the sensor to serve as transmitter and receiver antennas, we achieved to transfer contactless power and read out loads in the absence of direct wiring to the sensor. With this model, where telemetric measurements become simpler due to the fact that all sensor system is built on the same chip, we obtain a frequency shift of ~190 MHz with an increase in the quality factor from ~38 to ~46 when a load of 3920 N is applied. Therefore, as a first proof of concept, we have demonstrated the feasibility of our on-chip strain sensors for monitoring the mechanical deformation using telemetry-based systems.

Imaging Radar in the Mojave Desert-Death Valley Region

NASA Technical Reports Server (NTRS)

Farr, Tom G.

2001-01-01

The Mojave Desert-Death Valley region has had a long history as a test bed for remote sensing techniques. Along with visible-near infrared and thermal IR sensors, imaging radars have flown and orbited over the area since the 1970's, yielding new insights into the geologic applications of these technologies. More recently, radar interferometry has been used to derive digital topographic maps of the area, supplementing the USGS 7.5' digital quadrangles currently available for nearly the entire area. As for their shorter-wavelength brethren, imaging radars were tested early in their civilian history in the Mojave Desert-Death Valley region because it contains a variety of surface types in a small area without the confounding effects of vegetation. The earliest imaging radars to be flown over the region included military tests of short-wavelength (3 cm) X-band sensors. Later, the Jet Propulsion Laboratory began its development of imaging radars with an airborne sensor, followed by the Seasat orbital radar in 1978. These systems were L-band (25 cm). Following Seasat, JPL embarked upon a series of Space Shuttle Imaging Radars: SIRA (1981), SIR-B (1984), and SIR-C (1994). The most recent in the series was the most capable radar sensor flown in space and acquired large numbers of data swaths in a variety of test areas around the world. The Mojave Desert-Death Valley region was one of those test areas, and was covered very well with 3 wavelengths, multiple polarizations, and at multiple angles. At the same time, the JPL aircraft radar program continued improving and collecting data over the Mojave Desert Death Valley region. Now called AIRSAR, the system includes 3 bands (P-band, 67 cm; L-band, 25 cm; C-band, 5 cm). Each band can collect all possible polarizations in a mode called polarimetry. In addition, AIRSAR can be operated in the TOPSAR mode wherein 2 antennas collect data interferometrically, yielding a digital elevation model (DEM). Both L-band and C-band can be operated in this way, with horizontal resolution of about 5 m and vertical errors less than 2 m. The findings and developments of these earlier investigations are discussed.

Graphical user interface for wireless sensor networks simulator

NASA Astrophysics Data System (ADS)

Paczesny, Tomasz; Paczesny, Daniel; Weremczuk, Jerzy

2008-01-01

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

Ti:LiNbO3 Integrated Optic Electric-Field Sensors based on Electro-Optic Effect

NASA Astrophysics Data System (ADS)

Jung, Hongsik

2016-07-01

The need for electric-field sensing technology has widely increased, playing a critical role in various scientific and technical areas. This article comprehensively reviews and compares Ti:LiNbO3 integrated optic electric-field sensors, including the asymmetric Mach-Zehnder interferometer (MZI), 1 × 2 directional coupler (DC), and Y-fed balanced-bridge Mach-Zehnder interferometer (YBB-MZI), based on the operating principles, the electrical and optical performance, and measurements of each fabricated device. We also discuss future works to improve the sensitivity, operating stability, response speed, and bandwidth.

ShakeMapple : tapping laptop motion sensors to map the felt extents of an earthquake

NASA Astrophysics Data System (ADS)

Bossu, Remy; McGilvary, Gary; Kamb, Linus

2010-05-01

There is a significant pool of untapped sensor resources available in portable computer embedded motion sensors. Included primarily to detect sudden strong motion in order to park the disk heads to prevent damage to the disks in the event of a fall or other severe motion, these sensors may also be tapped for other uses as well. We have developed a system that takes advantage of the Apple Macintosh laptops' embedded Sudden Motion Sensors to record earthquake strong motion data to rapidly build maps of where and to what extent an earthquake has been felt. After an earthquake, it is vital to understand the damage caused especially in urban environments as this is often the scene for large amounts of damage caused by earthquakes. Gathering as much information from these impacts to determine where the areas that are likely to be most effected, can aid in distributing emergency services effectively. The ShakeMapple system operates in the background, continuously saving the most recent data from the motion sensors. After an earthquake has occurred, the ShakeMapple system calculates the peak acceleration within a time window around the expected arrival and sends that to servers at the EMSC. A map plotting the felt responses is then generated and presented on the web. Because large-scale testing of such an application is inherently difficult, we propose to organize a broadly distributed "simulated event" test. The software will be available for download in April, after which we plan to organize a large-scale test by the summer. At a specified time, participating testers will be asked to create their own strong motion to be registered and submitted by the ShakeMapple client. From these responses, a felt map will be produced representing the broadly-felt effects of the simulated event.

A High-Performance Portable Transient Electro-Magnetic Sensor for Unexploded Ordnance Detection.

PubMed

Wang, Haofeng; Chen, Shudong; Zhang, Shuang; Yuan, Zhiwen; Zhang, Haiyang; Fang, Dong; Zhu, Jun

2017-11-17

Portable transient electromagnetic (TEM) systems can be well adapted to various terrains, including mountainous, woodland, and other complex terrains. They are widely used for the detection of unexploded ordnance (UXO). As the core component of the portable TEM system, the sensor is constructed with a transmitting coil and a receiving coil. Based on the primary field of the transmitting coil and internal noise of the receiving coil, the design and testing of such a sensor is described in detail. Results indicate that the primary field of the transmitting coil depends on the diameter, mass, and power of the coil. A higher mass-power product and a larger diameter causes a stronger primary field. Reducing the number of turns and increasing the clamp voltage reduces the switch-off time of the transmitting current effectively. Increasing the cross-section of the wire reduces the power consumption, but greatly increases the coil's weight. The study of the receiving coil shows that the internal noise of the sensor is dominated by the thermal noise of the damping resistor. Reducing the bandwidth of the system and increasing the size of the coil reduces the internal noise effectively. The cross-sectional area and the distance between the sections of the coil have little effect on the internal noise. A less damped state can effectively reduce signal distortion. Finally, a portable TEM sensor with both a transmitting coil (constructed with a diameter, number of turns, and transmitting current of 0.5 m, 30, and 5 A, respectively) and a receiving coil (constructed with a length and resonant frequency of 5.6 cm and 50 kHz, respectively) was built. The agreement between experimental and calculated results confirms the theory used in the sensor design. The responses of an 82 mm mortar shell at different distances were measured and inverted by the differential evolution (DE) algorithm to verify system performance. Results show that the sensor designed in this study can not only detect the 82 mm mortar shell within 1.2 m effectively but also locate the target precisely.

Connectivity, Coverage and Placement in Wireless Sensor Networks

PubMed Central

Li, Ji; Andrew, Lachlan L.H.; Foh, Chuan Heng; Zukerman, Moshe; Chen, Hsiao-Hwa

2009-01-01

Wireless communication between sensors allows the formation of flexible sensor networks, which can be deployed rapidly over wide or inaccessible areas. However, the need to gather data from all sensors in the network imposes constraints on the distances between sensors. This survey describes the state of the art in techniques for determining the minimum density and optimal locations of relay nodes and ordinary sensors to ensure connectivity, subject to various degrees of uncertainty in the locations of the nodes. PMID:22408474

30 CFR 75.1107-4 - Automatic fire sensors and manual actuators; installation; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic fire sensors and manual actuators... § 75.1107-4 Automatic fire sensors and manual actuators; installation; minimum requirements. (a)(1... sensors or equivalent shall be installed for each 50 square feet of top surface area, or fraction thereof...

Community Air Sensor Network (CAIRSENSE) project: Evaluation of low-cost sensor performance in a suburban environment in the southeastern United States

EPA Science Inventory

Advances in air pollution sensor technology have enabled the development of small and low cost systems to measure outdoor air pollution. The deployment of a large number of sensors across a small geographic area would have potential benefits to supplement traditional monitoring n...

Low-cost flexible thin-film detector for medical dosimetry applications.

PubMed

Zygmanski, P; Abkai, C; Han, Z; Shulevich, Y; Menichelli, D; Hesser, J

2014-03-06

The purpose of this study is to characterize dosimetric properties of thin film photovoltaic sensors as a platform for development of prototype dose verification equipment in radiotherapy. Towards this goal, flexible thin-film sensors of dose with embedded data acquisition electronics and wireless data transmission are prototyped and tested in kV and MV photon beams. Fundamental dosimetric properties are determined in view of a specific application to dose verification in multiple planes or curved surfaces inside a phantom. Uniqueness of the new thin-film sensors consists in their mechanical properties, low-power operation, and low-cost. They are thinner and more flexible than dosimetric films. In principle, each thin-film sensor can be fabricated in any size (mm² - cm² areas) and shape. Individual sensors can be put together in an array of sensors spreading over large areas and yet being light. Photovoltaic mode of charge collection (of electrons and holes) does not require external electric field applied to the sensor, and this implies simplicity of data acquisition electronics and low power operation. The prototype device used for testing consists of several thin film dose sensors, each of about 1.5 cm × 5 cm area, connected to simple readout electronics. Sensitivity of the sensors is determined per unit area and compared to EPID sensitivity, as well as other standard photodiodes. Each sensor independently measures dose and is based on commercially available flexible thin-film aSi photodiodes. Readout electronics consists of an ultra low-power microcontroller, radio frequency transmitter, and a low-noise amplification circuit implemented on a flexible printed circuit board. Detector output is digitized and transmitted wirelessly to an external host computer where it is integrated and processed. A megavoltage medical linear accelerator (Varian Tx) equipped with kilovoltage online imaging system and a Cobalt source are used to irradiate different thin-film detector sensors in a Solid Water phantom under various irradiation conditions. Different factors are considered in characterization of the device attributes: energies (80 kVp, 130 kVp, 6 MV, 15 MV), dose rates (different ms × mA, 100-600 MU/min), total doses (0.1 cGy-500 cGy), depths (0.5 cm-20 cm), irradiation angles with respect to the detector surface (0°-180°), and IMRT tests (closed MLC, sweeping gap). The detector response to MV radiation is both linear with total dose (~1-400 cGy) and independent of dose rate (100-600 Mu/min). The sensitivity per unit area of thin-film sensors is lower than for aSi flat-panel detectors, but sufficient to acquire stable and accurate signals during irradiations. The proposed thin-film photodiode system has properties which make it promising for clinical dosimetry. Due to the mechanical flexibility of each sensor and readout electronics, low-cost, and wireless data acquisition, it could be considered for quality assurance (e.g., IMRT, mechanical linac QA), as well as real-time dose monitoring in challenging setup configurations, including large area and 3D detection (multiple planes or curved surfaces).

Low‐cost flexible thin‐film detector for medical dosimetry applications

PubMed Central

Abkai, C.; Han, Z.; Shulevich, Y.; Menichelli, D.; Hesser, J.

2014-01-01

The purpose of this study is to characterize dosimetric properties of thin film photovoltaic sensors as a platform for development of prototype dose verification equipment in radiotherapy. Towards this goal, flexible thin‐film sensors of dose with embedded data acquisition electronics and wireless data transmission are prototyped and tested in kV and MV photon beams. Fundamental dosimetric properties are determined in view of a specific application to dose verification in multiple planes or curved surfaces inside a phantom. Uniqueness of the new thin‐film sensors consists in their mechanical properties, low‐power operation, and low‐cost. They are thinner and more flexible than dosimetric films. In principle, each thin‐film sensor can be fabricated in any size (mm2 – cm2 areas) and shape. Individual sensors can be put together in an array of sensors spreading over large areas and yet being light. Photovoltaic mode of charge collection (of electrons and holes) does not require external electric field applied to the sensor, and this implies simplicity of data acquisition electronics and low power operation. The prototype device use for testing consists of several thin film dose sensors, each of about 1.5 cm×5 cm area, connected to simple readout electronics. Sensitivity of the sensors is determined per unit area and compared to EPID sensitivity, as well as other standard photodiodes. Each sensor independently measures dose and is based on commercially available flexible thin‐film aSi photodiodes. Readout electronics consists of an ultra low‐power microcontroller, radio frequency transmitter, and a low‐noise amplification circuit implemented on a flexible printed circuit board. Detector output is digitized and transmitted wirelessly to an external host computer where it is integrated and processed. A megavoltage medical linear accelerator (Varian Tx) equipped with kilovoltage online imaging system and a Cobalt source are use to irradiate different thin‐film detector sensors in a Solid Water phantom under various irradiation conditions. Different factors are considered in characterization of the device attributes: energies (80 kVp, 130 kVp, 6 MV, 15 MV), dose rates (different ms × mA, 100–600 MU/min), total doses (0.1 cGy‐500 cGy), depths (0.5 cm–20 cm), irradiation angles with respect to the detector surface (0°‐180°), and IMRT tests (closed MLC, sweeping gap). The detector response to MV radiation is both linear with total dose (~1‐400 cGy) and independent of dose rate (100‐600 Mu/min). The sensitivity per unit area of thin‐film sensors is lower than for aSi flat‐panel detectors, but sufficient to acquire stable and accurate signals during irradiations. The proposed thin‐film photodiode system has properties which make it promising for clinical dosimetry. Due to the mechanical flexibility of each sensor and readout electronics, low‐cost, and wireless data acquisition, it could be considered for quality assurance (e.g., IMRT, mechanical linac QA), as well as real‐time dose monitoring in challenging setup configurations, including large area and 3D detection (multiple planes or curved surfaces). PACS number: 87.56.Fc PMID:24710432

ADAPTING FTIR MEASUREMENT TECHNOLOGY TO HOMELAND SECURITY APPLICATIONS

EPA Science Inventory

Open-path Fourier transform infrared (OP-FTIR) sensors have numerous advantages for measuring chemical plumes over wide areas compared to point detection sensors. Extractive FTIR sensors have been used for industrial stack monitoring and are attractive for building ventilation sy...

Motion perception: behavior and neural substrate.

PubMed

Mather, George

2011-05-01

Visual motion perception is vital for survival. Single-unit recordings in primate primary visual cortex (V1) have revealed the existence of specialized motion sensing neurons; perceptual effects such as the motion after-effect demonstrate their importance for motion perception. Human psychophysical data on motion detection can be explained by a computational model of cortical motion sensors. Both psychophysical and physiological data reveal at least two classes of motion sensor capable of sensing motion in luminance-defined and texture-defined patterns, respectively. Psychophysical experiments also reveal that motion can be seen independently of motion sensor output, based on attentive tracking of visual features. Sensor outputs are inherently ambiguous, due to the problem of univariance in neural responses. In order to compute stimulus direction and speed, the visual system must compare the responses of many different sensors sensitive to different directions and speeds. Physiological data show that this computation occurs in the visual middle temporal (MT) area. Recent psychophysical studies indicate that information about spatial form may also play a role in motion computations. Adaptation studies show that the human visual system is selectively sensitive to large-scale optic flow patterns, and physiological studies indicate that cells in the middle superior temporal (MST) area derive this sensitivity from the combined responses of many MT cells. Extraretinal signals used to control eye movements are an important source of signals to cancel out the retinal motion responses generated by eye movements, though visual information also plays a role. A number of issues remain to be resolved at all levels of the motion-processing hierarchy. WIREs Cogni Sci 2011 2 305-314 DOI: 10.1002/wcs.110 For further resources related to this article, please visit the WIREs website Additional Supporting Information may be found in http://www.lifesci.sussex.ac.uk/home/George_Mather/Motion/index.html. Copyright © 2010 John Wiley & Sons, Ltd.

A new approach for river flood extent delineation in rural and urban areas combining RADARSAT-2 imagery and flood recurrence interval data

NASA Astrophysics Data System (ADS)

Tanguy, Marion; Bernier, Monique; Chokmani, Karem

2015-04-01

When a flood hits an inhabited area, managers and services responsible for public safety need precise, reliable and up to date maps of the areas affected by the flood, in order to quickly roll out and to coordinate the adequate intervention and assistance plans required to limit the human and material damages caused by the disaster. Synthetic aperture radar (SAR) sensors are now considered as one of the most adapted tool for flood detection and mapping in a context of crisis management. Indeed, due to their capacity to acquire data night and day, in almost all meteorological conditions, SAR sensors allow the acquisition of synoptic but detailed views of the areas affected by the flood, even during the active phases of the event. Moreover, new generation sensors such as RADARSAT-2, TerraSAR-X, COSMO-SkyMed, are providing very high resolution images of the disaster (down to 1m ground resolution). Further, critical improvements have been made on the temporal repetitivity of acquisitions and on data availability, through the development of satellite constellations (i.e the four COSMO-Skymed or the Sentinel-1A and 1B satellites) and thanks to the implementation of the International Charter "Space and Major Disasters", which guarantees high priority images acquisition and delivery with 4 to 12 hours. If detection of open water flooded areas is relatively straightforward with SAR imagery, flood detection in built-up areas is often associated with important issues. Indeed, because of the side looking geometry of the SAR sensors, structures such as tall vegetation and structures parallel to the satellite direction of travel may produce shadow and layover effects, leading to important over and under-detections of flooded pixels. Besides, the numerous permanent water-surfaces like radar response areas present in built-up environments, such as parking lots, roads etc., may be mixed up with flooded areas, resulting in substantial inaccuracies in the final flood map. In spite of the many efforts recently done toward the improvements of the accuracy of the processing algorithms for flood detection in urban areas with high resolution SAR imagery, these algorithms still encounter difficulties to detect urban flooded pixels with precision. The difficulties do not seem to be only ascribable to the choice of SAR image processing methods, but can also be imputed to the limitations of the SAR imaging technique itself in urban areas. We propose a fully automatic and effective approach for near-real time delineation of urban and rural flooded areas, which combines the capacity of SAR imagery to detect open water areas, and explicit hydrodynamic characteristics of the region affected by the flood, expressed through flood recurrence interval data. This innovative approach has been tested with RADARSAT-2 Fine and Ultrafine Mode images acquired during the 2011 Richelieu River flooding, in Canada. It proved successful in accurately delineating flooding in urban and rural areas, with a RMSE inferior to 2 pixels.

Towards real-time topical detection and characterization of FDG dose infiltration prior to PET imaging.

PubMed

Williams, Jason M; Arlinghaus, Lori R; Rani, Sudheer D; Shone, Martha D; Abramson, Vandana G; Pendyala, Praveen; Chakravarthy, A Bapsi; Gorge, William J; Knowland, Joshua G; Lattanze, Ronald K; Perrin, Steven R; Scarantino, Charles W; Townsend, David W; Abramson, Richard G; Yankeelov, Thomas E

2016-12-01

To dynamically detect and characterize 18 F-fluorodeoxyglucose (FDG) dose infiltrations and evaluate their effects on positron emission tomography (PET) standardized uptake values (SUV) at the injection site and in control tissue. Investigational gamma scintillation sensors were topically applied to patients with locally advanced breast cancer scheduled to undergo limited whole-body FDG-PET as part of an ongoing clinical study. Relative to the affected breast, sensors were placed on the contralateral injection arm and ipsilateral control arm during the resting uptake phase prior to each patient's PET scan. Time-activity curves (TACs) from the sensors were integrated at varying intervals (0-10, 0-20, 0-30, 0-40, and 30-40 min) post-FDG and the resulting areas under the curve (AUCs) were compared to SUVs obtained from PET. In cases of infiltration, observed in three sensor recordings (30 %), the injection arm TAC shape varied depending on the extent and severity of infiltration. In two of these cases, TAC characteristics suggested the infiltration was partially resolving prior to image acquisition, although it was still apparent on subsequent PET. Areas under the TAC 0-10 and 0-20 min post-FDG were significantly different in infiltrated versus non-infiltrated cases (Mann-Whitney, p < 0.05). When normalized to control, all TAC integration intervals from the injection arm were significantly correlated with SUV peak and SUV max measured over the infiltration site (Spearman ρ ≥ 0.77, p < 0.05). Receiver operating characteristic (ROC) analyses, testing the ability of the first 10 min of post-FDG sensor data to predict infiltration visibility on the ensuing PET, yielded an area under the ROC curve of 0.92. Topical sensors applied near the injection site provide dynamic information from the time of FDG administration through the uptake period and may be useful in detecting infiltrations regardless of PET image field of view. This dynamic information may also complement the static PET image to better characterize the true extent of infiltrations.

Wide area sensor network

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Sanjoy; Nix, Tricia; Junker, Robert; Brentano, Josef; Khona, Dhiren

2006-05-01

The technical concept for this project has existed since the Chernobyl accident in 1986. A host of Eastern European nations have developed countrywide grid of sensors to monitor airborne radiation. The objective is to build a radiological sensor network for real-time monitoring of environmental radiation levels in order to provide data for warning, and consequentially the assessment of a nuclear event. A network of radiation measuring equipment consisting of gamma, neutron, alpha, and beta counters would be distributed over a large area (preferably on fire station roof tops) and connected by a wireless network to the emergency response center. The networks would be deployed in urban environments and would supply first responders and federal augmentation teams (including those from the U.S. Departments of Energy, Defense, Justice, and Homeland Security) with detailed, accurate information regarding the transport of radioactive environmental contaminants, so the agencies can provide a safe and effective response. A networked sensor capability would be developed, with fixed sensors deployed at key locations and in sufficient numbers, to provide adequate coverage for early warning, and input to post-event emergency response. An overall system description and specification will be provided, including detector characteristics, communication protocols, infrastructure and maintenance requirements, and operation procedures. The system/network can be designed for a specifically identified urban area, or for a general urban area scalable to cities of specified size. Data collected via the network will be transmitted directly to the appropriate emergency response center and shared with multiple agencies via the Internet or an Intranet. The data collected will be managed using commercial off - the - shelf Geographical Information System (GIS). The data will be stored in a database and the GIS software will aid in analysis and management of the data. Unique features of the system include each node being assigned a health-effect based risk factor. By connecting the nodes on a particular measured isopleth one can define the plume accurately. Radon counts will be provided and used to calculate the alpha counts. The radiological data collected will also be of value under routine conditions, in the absence of a radiological threat, to provide a detailed map of radiation background in the urban environment and complement predictive models of radiation transport. The data can be transferred to the National Atmospheric Release Advisory Center (NARAC) to augment its predictive model, thereby increasing its fidelity. Initially, as a proof of concept, a few nodes will be built for the purpose of demonstrating the concept.

Photosynthetically Driven Cycles Produce Extreme pCO2Variability in a Large Eelgrass Meadow and Readily Measured Proxies Can Be Used to Estimate These Changes

NASA Astrophysics Data System (ADS)

Love, B. A.; O'Brien, C.; Bohlmann, H.

2016-02-01

Declining ocean pH has spurred research into the effects of marine carbonate chemistry on a variety of organisms, but less work has focused on the potential role of organisms in changing local carbonate chemistry. It has been suggested that photosynthetic activity of macrophytes in coastal areas can decrease pCO2, increase pH, and may provide areas of refuge for organisms sensitive to ocean acidification. To assess the effect of a large eelgrass meadow on water chemistry, discreet samples were collected hourly over several 24 hour cycles in Padilla Bay, Washington. Calculated pCO2 ranged from less than 100 ppm to greater than 700 ppm, often over the course of only a few hours. Aragonite saturation, DIC and pH were also highly variable. In -situ sensors, including a YSI glass electrode, a custom built DuraFET sensor and a SeaFET sensor were co-deployed to provide a high frequency record of water chemistry over several months. These data, (discrete samples and sensors) were used to develop a model that estimates pCO2 for the summer season based on readily measured parameters. Tidal height, photosynthetically active radiation and pH can predict pCO2 reasonably well in this environment. We compare the data from the 3 pH sensors and analyze the quality of data and predictions based on each one. A simple theoretical model shows that the large observed and modeled changes in pCO2 and pH (up to 800 ppm CO2 or 1 pH unit per day) match the magnitude of changes expected based on experimentally derived photosynthetic rates, measured light and water depth and that CO2 fluxes from gas exchange are expected to be small compared to photosynthetic fluxes in this environment. This study illustrates how eelgrass meadows do have the potential to create favorable carbonate chemistry, and demonstrates both the temporally variable nature of that effect and the possibility of better understanding when and how long it occurs through relatively simple modeling of the system.

Ultra-wideband impedance sensor

DOEpatents

McEwan, Thomas E.

1999-01-01

The ultra-wideband impedance sensor (UWBZ sensor, or Z-sensor) is implemented in differential and single-ended configurations. The differential UWBZ sensor employs a sub-nanosecond impulse to determine the balance of an impedance bridge. The bridge is configured as a differential sample-and-hold circuit that has a reference impedance side and an unknown impedance side. The unknown impedance side includes a short transmission line whose impedance is a function of the near proximity of objects. The single-ended UWBZ sensor eliminates the reference side of the bridge and is formed of a sample and hold circuit having a transmission line whose impedance is a function of the near proximity of objects. The sensing range of the transmission line is bounded by the two-way travel time of the impulse, thereby eliminating spurious Doppler modes from large distant objects that would occur in a microwave CW impedance bridge. Thus, the UWBZ sensor is a range-gated proximity sensor. The Z-sensor senses the near proximity of various materials such as metal, plastic, wood, petroleum products, and living tissue. It is much like a capacitance sensor, yet it is impervious to moisture. One broad application area is the general replacement of magnetic sensors, particularly where nonferrous materials need to be sensed. Another broad application area is sensing full/empty levels in tanks, vats and silos, e.g., a full/empty switch in water or petroleum tanks.

Ultra-wideband impedance sensor

DOEpatents

McEwan, T.E.

1999-03-16

The ultra-wideband impedance sensor (UWBZ sensor, or Z-sensor) is implemented in differential and single-ended configurations. The differential UWBZ sensor employs a sub-nanosecond impulse to determine the balance of an impedance bridge. The bridge is configured as a differential sample-and-hold circuit that has a reference impedance side and an unknown impedance side. The unknown impedance side includes a short transmission line whose impedance is a function of the near proximity of objects. The single-ended UWBZ sensor eliminates the reference side of the bridge and is formed of a sample and hold circuit having a transmission line whose impedance is a function of the near proximity of objects. The sensing range of the transmission line is bounded by the two-way travel time of the impulse, thereby eliminating spurious Doppler modes from large distant objects that would occur in a microwave CW impedance bridge. Thus, the UWBZ sensor is a range-gated proximity sensor. The Z-sensor senses the near proximity of various materials such as metal, plastic, wood, petroleum products, and living tissue. It is much like a capacitance sensor, yet it is impervious to moisture. One broad application area is the general replacement of magnetic sensors, particularly where nonferrous materials need to be sensed. Another broad application area is sensing full/empty levels in tanks, vats and silos, e.g., a full/empty switch in water or petroleum tanks. 2 figs.

Autonomous collection of dynamically-cued multi-sensor imagery

NASA Astrophysics Data System (ADS)

Daniel, Brian; Wilson, Michael L.; Edelberg, Jason; Jensen, Mark; Johnson, Troy; Anderson, Scott

2011-05-01

The availability of imagery simultaneously collected from sensors of disparate modalities enhances an image analyst's situational awareness and expands the overall detection capability to a larger array of target classes. Dynamic cooperation between sensors is increasingly important for the collection of coincident data from multiple sensors either on the same or on different platforms suitable for UAV deployment. Of particular interest is autonomous collaboration between wide area survey detection, high-resolution inspection, and RF sensors that span large segments of the electromagnetic spectrum. The Naval Research Laboratory (NRL) in conjunction with the Space Dynamics Laboratory (SDL) is building sensors with such networked communications capability and is conducting field tests to demonstrate the feasibility of collaborative sensor data collection and exploitation. Example survey / detection sensors include: NuSAR (NRL Unmanned SAR), a UAV compatible synthetic aperture radar system; microHSI, an NRL developed lightweight hyper-spectral imager; RASAR (Real-time Autonomous SAR), a lightweight podded synthetic aperture radar; and N-WAPSS-16 (Nighttime Wide-Area Persistent Surveillance Sensor-16Mpix), a MWIR large array gimbaled system. From these sensors, detected target cues are automatically sent to the NRL/SDL developed EyePod, a high-resolution, narrow FOV EO/IR sensor, for target inspection. In addition to this cooperative data collection, EyePod's real-time, autonomous target tracking capabilities will be demonstrated. Preliminary results and target analysis will be presented.

Hyperspectral Features of Oil-Polluted Sea Ice and the Response to the Contamination Area Fraction

PubMed Central

Li, Ying; Liu, Chengyu; Xie, Feng

2018-01-01

Researchers have studied oil spills in open waters using remote sensors, but few have focused on extracting reflectance features of oil pollution on sea ice. An experiment was conducted on natural sea ice in Bohai Bay, China, to obtain the spectral reflectance of oil-contaminated sea ice. The spectral absorption index (SAI), spectral peak height (SPH), and wavelet detail coefficient (DWT d5) were calculated using stepwise multiple linear regression. The reflectances of some false targets were measured and analysed. The simulated false targets were sediment, iron ore fines, coal dust, and the melt pool. The measured reflectances were resampled using five common sensors (GF-2, Landsat8-OLI, Sentinel3-OLCI, MODIS, and AVIRIS). Some significant spectral features could discriminate between oil-polluted and clean sea ice. The indices correlated well with the oil area fractions. All of the adjusted R2 values exceeded 0.9. The SPH model1, based on spectral features at 507–670 and 1627–1746 nm, displayed the best fitting. The resampled data indicated that these multi-spectral and hyper-spectral sensors could be used to detect crude oil on the sea ice if the effect of noise and spatial resolution are neglected. The spectral features and their identified changes may provide reference on sensor design and band selection. PMID:29342945

Design and Analysis of Cost-Efficient Sensor Deployment for Tracking Small UAS with Agent-Based Modeling.

PubMed

Shin, Sangmi; Park, Seongha; Kim, Yongho; Matson, Eric T

2016-04-22

Recently, commercial unmanned aerial systems (UAS) have gained popularity. However, these UAS are potential threats to people in terms of safety in public places, such as public parks or stadiums. To reduce such threats, we consider a design, modeling, and evaluation of a cost-efficient sensor system that detects and tracks small UAS. In this research, we focus on discovering the best sensor deployments by simulating different types and numbers of sensors in a designated area, which provide reasonable detection rates at low costs. Also, the system should cover the crowded areas more thoroughly than vacant areas to reduce direct threats to people underneath. This research study utilized the Agent-Based Modeling (ABM) technique to model a system consisting of independent and heterogeneous agents that interact with each other. Our previous work presented the ability to apply ABM to analyze the sensor configurations with two types of radars in terms of cost-efficiency. The results from the ABM simulation provide a list of candidate configurations and deployments that can be referred to for applications in the real world environment.

Design and Analysis of Cost-Efficient Sensor Deployment for Tracking Small UAS with Agent-Based Modeling

PubMed Central

Shin, Sangmi; Park, Seongha; Kim, Yongho; Matson, Eric T.

2016-01-01

Recently, commercial unmanned aerial systems (UAS) have gained popularity. However, these UAS are potential threats to people in terms of safety in public places, such as public parks or stadiums. To reduce such threats, we consider a design, modeling, and evaluation of a cost-efficient sensor system that detects and tracks small UAS. In this research, we focus on discovering the best sensor deployments by simulating different types and numbers of sensors in a designated area, which provide reasonable detection rates at low costs. Also, the system should cover the crowded areas more thoroughly than vacant areas to reduce direct threats to people underneath. This research study utilized the Agent-Based Modeling (ABM) technique to model a system consisting of independent and heterogeneous agents that interact with each other. Our previous work presented the ability to apply ABM to analyze the sensor configurations with two types of radars in terms of cost-efficiency. The results from the ABM simulation provide a list of candidate configurations and deployments that can be referred to for applications in the real world environment. PMID:27110790

Superwetting and aptamer functionalized shrink-induced high surface area electrochemical sensors.

PubMed

Hauke, A; Kumar, L S Selva; Kim, M Y; Pegan, J; Khine, M; Li, H; Plaxco, K W; Heikenfeld, J

2017-08-15

Electrochemical sensing is moving to the forefront of point-of-care and wearable molecular sensing technologies due to the ability to miniaturize the required equipment, a critical advantage over optical methods in this field. Electrochemical sensors that employ roughness to increase their microscopic surface area offer a strategy to combatting the loss in signal associated with the loss of macroscopic surface area upon miniaturization. A simple, low-cost method of creating such roughness has emerged with the development of shrink-induced high surface area electrodes. Building on this approach, we demonstrate here a greater than 12-fold enhancement in electrochemically active surface area over conventional electrodes of equivalent on-chip footprint areas. This two-fold improvement on previous performance is obtained via the creation of a superwetting surface condition facilitated by a dissolvable polymer coating. As a test bed to illustrate the utility of this approach, we further show that electrochemical aptamer-based sensors exhibit exceptional signal strength (signal-to-noise) and excellent signal gain (relative change in signal upon target binding) when deployed on these shrink electrodes. Indeed, the observed 330% gain we observe for a kanamycin sensor is 2-fold greater than that seen on planar gold electrodes. Copyright © 2017 Elsevier B.V. All rights reserved.

Low-power cryptographic coprocessor for autonomous wireless sensor networks

NASA Astrophysics Data System (ADS)

Olszyna, Jakub; Winiecki, Wiesław

2013-10-01

The concept of autonomous wireless sensor networks involves energy harvesting, as well as effective management of system resources. Public-key cryptography (PKC) offers the advantage of elegant key agreement schemes with which a secret key can be securely established over unsecure channels. In addition to solving the key management problem, the other major application of PKC is digital signatures, with which non-repudiation of messages exchanges can be achieved. The motivation for studying low-power and area efficient modular arithmetic algorithms comes from enabling public-key security for low-power devices that can perform under constrained environment like autonomous wireless sensor networks. This paper presents a cryptographic coprocessor tailored to the autonomous wireless sensor networks constraints. Such hardware circuit is aimed to support the implementation of different public-key cryptosystems based on modular arithmetic in GF(p) and GF(2m). Key components of the coprocessor are described as GEZEL models and can be easily transformed to VHDL and implemented in hardware.

A Low Power IoT Sensor Node Architecture for Waste Management Within Smart Cities Context.

PubMed

Cerchecci, Matteo; Luti, Francesco; Mecocci, Alessandro; Parrino, Stefano; Peruzzi, Giacomo; Pozzebon, Alessandro

2018-04-21

This paper focuses on the realization of an Internet of Things (IoT) architecture to optimize waste management in the context of Smart Cities. In particular, a novel typology of sensor node based on the use of low cost and low power components is described. This node is provided with a single-chip microcontroller, a sensor able to measure the filling level of trash bins using ultrasounds and a data transmission module based on the LoRa LPWAN (Low Power Wide Area Network) technology. Together with the node, a minimal network architecture was designed, based on a LoRa gateway, with the purpose of testing the IoT node performances. Especially, the paper analyzes in detail the node architecture, focusing on the energy saving technologies and policies, with the purpose of extending the batteries lifetime by reducing power consumption, through hardware and software optimization. Tests on sensor and radio module effectiveness are also presented.

Flexible and self-powered temperature-pressure dual-parameter sensors using microstructure-frame-supported organic thermoelectric materials.

PubMed

Zhang, Fengjiao; Zang, Yaping; Huang, Dazhen; Di, Chong-an; Zhu, Daoben

2015-09-21

Skin-like temperature- and pressure-sensing capabilities are essential features for the next generation of artificial intelligent products. Previous studies of e-skin and smart elements have focused on flexible pressure sensors, whereas the simultaneous and sensitive detection of temperature and pressure with a single device remains a challenge. Here we report developing flexible dual-parameter temperature-pressure sensors based on microstructure-frame-supported organic thermoelectric (MFSOTE) materials. The effective transduction of temperature and pressure stimuli into two independent electrical signals permits the instantaneous sensing of temperature and pressure with an accurate temperature resolution of <0.1 K and a high-pressure-sensing sensitivity of up to 28.9 kPa(-1). More importantly, these dual-parameter sensors can be self-powered with outstanding sensing performance. The excellent sensing properties of MFSOTE-based devices, together with their unique advantages of low cost and large-area fabrication, make MFSOTE materials possess promising applications in e-skin and health-monitoring elements.

A Low Power IoT Sensor Node Architecture for Waste Management Within Smart Cities Context

PubMed Central

Cerchecci, Matteo; Luti, Francesco; Mecocci, Alessandro; Parrino, Stefano; Peruzzi, Giacomo

2018-01-01

This paper focuses on the realization of an Internet of Things (IoT) architecture to optimize waste management in the context of Smart Cities. In particular, a novel typology of sensor node based on the use of low cost and low power components is described. This node is provided with a single-chip microcontroller, a sensor able to measure the filling level of trash bins using ultrasounds and a data transmission module based on the LoRa LPWAN (Low Power Wide Area Network) technology. Together with the node, a minimal network architecture was designed, based on a LoRa gateway, with the purpose of testing the IoT node performances. Especially, the paper analyzes in detail the node architecture, focusing on the energy saving technologies and policies, with the purpose of extending the batteries lifetime by reducing power consumption, through hardware and software optimization. Tests on sensor and radio module effectiveness are also presented. PMID:29690552

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

PubMed Central

2017-01-01

Underwater sensors provide one of the possibilities to explore oceans, seas, rivers, fish farms and dams, which all together cover most of our planet’s area. Simulators can be helpful to test and discover some possible strategies before implementing these in real underwater sensors. This speeds up the development of research theories so that these can be implemented later. In this context, the current work presents an agent-based simulator for defining and testing strategies for measuring the amount of fish by means of underwater sensors. The current approach is illustrated with the definition and assessment of two strategies for measuring fish. One of these two corresponds to a simple control mechanism, while the other is an experimental strategy and includes an implicit coordination mechanism. The experimental strategy showed a statistically significant improvement over the control one in the reduction of errors with a large Cohen’s d effect size of 2.55. PMID:29137165

Flexible and self-powered temperature-pressure dual-parameter sensors using microstructure-frame-supported organic thermoelectric materials

NASA Astrophysics Data System (ADS)

Zhang, Fengjiao; Zang, Yaping; Huang, Dazhen; di, Chong-An; Zhu, Daoben

2015-09-01

Skin-like temperature- and pressure-sensing capabilities are essential features for the next generation of artificial intelligent products. Previous studies of e-skin and smart elements have focused on flexible pressure sensors, whereas the simultaneous and sensitive detection of temperature and pressure with a single device remains a challenge. Here we report developing flexible dual-parameter temperature-pressure sensors based on microstructure-frame-supported organic thermoelectric (MFSOTE) materials. The effective transduction of temperature and pressure stimuli into two independent electrical signals permits the instantaneous sensing of temperature and pressure with an accurate temperature resolution of <0.1 K and a high-pressure-sensing sensitivity of up to 28.9 kPa-1. More importantly, these dual-parameter sensors can be self-powered with outstanding sensing performance. The excellent sensing properties of MFSOTE-based devices, together with their unique advantages of low cost and large-area fabrication, make MFSOTE materials possess promising applications in e-skin and health-monitoring elements.

Multisensor fusion for 3-D defect characterization using wavelet basis function neural networks

NASA Astrophysics Data System (ADS)

Lim, Jaein; Udpa, Satish S.; Udpa, Lalita; Afzal, Muhammad

2001-04-01

The primary objective of multi-sensor data fusion, which offers both quantitative and qualitative benefits, has the ability to draw inferences that may not be feasible with data from a single sensor alone. In this paper, data from two sets of sensors are fused to estimate the defect profile from magnetic flux leakage (MFL) inspection data. The two sensors measure the axial and circumferential components of the MFL. Data is fused at the signal level. If the flux is oriented axially, the samples of the axial signal are measured along a direction parallel to the flaw, while the circumferential signal is measured in a direction that is perpendicular to the flaw. The two signals are combined as the real and imaginary components of a complex valued signal. Signals from an array of sensors are arranged in contiguous rows to obtain a complex valued image. A boundary extraction algorithm is used to extract the defect areas in the image. Signals from the defect regions are then processed to minimize noise and the effects of lift-off. Finally, a wavelet basis function (WBF) neural network is employed to map the complex valued image appropriately to obtain the geometrical profile of the defect. The feasibility of the approach was evaluated using the data obtained from the MFL inspection of natural gas transmission pipelines. Results show the effectiveness of the approach.

Flexible phosphor sensors: a digital supplement or option to rigid sensors.

PubMed

Glazer, Howard S

2014-01-01

An increasing number of dental practices are upgrading from film radiography to digital radiography, for reasons that include faster image processing, easier image access, better patient education, enhanced data storage, and improved office productivity. Most practices that have converted to digital technology use rigid, or direct, sensors. Another digital option is flexible phosphor sensors, also called indirect sensors or phosphor storage plates (PSPs). Flexible phosphor sensors can be advantageous for use with certain patients who may be averse to direct sensors, and they can deliver a larger image area. Additionally, sensor cost for replacement PSPs is considerably lower than for hard sensors. As such, flexible phosphor sensors appear to be a viable supplement or option to direct sensors.

Detection of Steel Fatigue Cracks with Strain Sensing Sheets Based on Large Area Electronics

PubMed Central

Yao, Yao; Glisic, Branko

2015-01-01

Reliable early-stage damage detection requires continuous monitoring over large areas of structure, and with sensors of high spatial resolution. Technologies based on Large Area Electronics (LAE) can enable direct sensing and can be scaled to the level required for Structural Health Monitoring (SHM) of civil structures and infrastructure. Sensing sheets based on LAE contain dense arrangements of thin-film strain sensors, associated electronics and various control circuits deposited and integrated on a flexible polyimide substrate that can cover large areas of structures. This paper presents the development stage of a prototype strain sensing sheet based on LAE for crack detection and localization. Two types of sensing-sheet arrangements with size 6 × 6 inch (152 × 152 mm) were designed and manufactured, one with a very dense arrangement of sensors and the other with a less dense arrangement of sensors. The sensing sheets were bonded to steel plates, which had a notch on the boundary, so the fatigue cracks could be generated under cyclic loading. The sensors within the sensing sheet that were close to the notch tip successfully detected the initialization of fatigue crack and localized the damage on the plate. The sensors that were away from the crack successfully detected the propagation of fatigue cracks based on the time history of the measured strain. The results of the tests have validated the general principles of the proposed sensing sheets for crack detection and identified advantages and challenges of the two tested designs. PMID:25853407

Development of Autonomous Magnetometer Rotorcraft For Wide Area Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mark D. McKay; Matthew O. Anderson

2011-08-01

Large areas across the United States and internationally are potentially contaminated with unexploded ordinance (UXO), with some ranges encompassing tens to hundreds of thousands of acres. Technologies are needed which will allow for cost effective wide area scanning with (1) near 100% coverage and (2) near 100% detection of subsurface ordnance or features indicative of subsurface ordnance. The current approach to wide area assessment is a multi-level one, in which medium - altitude fixed wing optical imaging is used for an initial site assessment. This assessment is followed with low altitude manned helicopter based magnetometry. Subsequent to this wide areamore » assessment targeted surface investigations are performed using either towed geophysical sensor arrays or man portable sensors. In order to be an effective tool for small UXO detection, the sensing altitude for magnetic site investigations needs to be on the order of 1 to 3 meters. These altitude requirements mean that manned helicopter surveys will generally only be feasible in large, open and relatively flat terrains. While such surveys are effective in mapping large areas relatively fast there are substantial mobilization/demobilization, staffing and equipment costs associated with these surveys, resulting in costs of approximately $100-$150/acre. In addition, due to the low altitude there are substantial risks to pilots and equipment. Surface towed arrays provide highresolution maps but have other limitations, e.g. in their ability to navigate rough terrain effectively. Thus there is a need for other systems, which can be used for effective data collection. An Unmanned Aerial Vehicle (UAV) magnetometer platform is an obvious alternative. The motivation behind such a system is that it reduces risk to operators, is lower in initial and Operational and Maintenance (O&M) costs (and can thus potentially be applied to smaller sites) and has the potential of being more effective in terms of detection and possibly characterization (through the use of dynamic acquisition, i.e. survey mission in-flight reprioritization).« less

Ultra-high gain diffusion-driven organic transistor.

PubMed

Torricelli, Fabrizio; Colalongo, Luigi; Raiteri, Daniele; Kovács-Vajna, Zsolt Miklós; Cantatore, Eugenio

2016-02-01

Emerging large-area technologies based on organic transistors are enabling the fabrication of low-cost flexible circuits, smart sensors and biomedical devices. High-gain transistors are essential for the development of large-scale circuit integration, high-sensitivity sensors and signal amplification in sensing systems. Unfortunately, organic field-effect transistors show limited gain, usually of the order of tens, because of the large contact resistance and channel-length modulation. Here we show a new organic field-effect transistor architecture with a gain larger than 700. This is the highest gain ever reported for organic field-effect transistors. In the proposed organic field-effect transistor, the charge injection and extraction at the metal-semiconductor contacts are driven by the charge diffusion. The ideal conditions of ohmic contacts with negligible contact resistance and flat current saturation are demonstrated. The approach is general and can be extended to any thin-film technology opening unprecedented opportunities for the development of high-performance flexible electronics.

Ultra-high gain diffusion-driven organic transistor

NASA Astrophysics Data System (ADS)

Torricelli, Fabrizio; Colalongo, Luigi; Raiteri, Daniele; Kovács-Vajna, Zsolt Miklós; Cantatore, Eugenio

2016-02-01

Emerging large-area technologies based on organic transistors are enabling the fabrication of low-cost flexible circuits, smart sensors and biomedical devices. High-gain transistors are essential for the development of large-scale circuit integration, high-sensitivity sensors and signal amplification in sensing systems. Unfortunately, organic field-effect transistors show limited gain, usually of the order of tens, because of the large contact resistance and channel-length modulation. Here we show a new organic field-effect transistor architecture with a gain larger than 700. This is the highest gain ever reported for organic field-effect transistors. In the proposed organic field-effect transistor, the charge injection and extraction at the metal-semiconductor contacts are driven by the charge diffusion. The ideal conditions of ohmic contacts with negligible contact resistance and flat current saturation are demonstrated. The approach is general and can be extended to any thin-film technology opening unprecedented opportunities for the development of high-performance flexible electronics.

Dual-hole Photonic Crystal Fiber Intermodal Interference based Refractometer

NASA Astrophysics Data System (ADS)

Liu, Feng; Guo, Xuan; Zhang, Qing; Fu, Xinghu

2017-12-01

A refractive-index (RI) sensor and its sensing characteristics based on intermodal interference of dual-hole Polarization Maintaining Photonic Crystal Fiber (PM-PCF) are demonstrated in this letter. The sensor works from the interference between LP01 and LP11 modes of hydrofluoric acid etched PM-PCF. The influence of corrosion zone radius on the RI sensing sensitivity is also discussed. Via choosing a 2.5 cm etched PM-PCF(the etched area radius is 27.5 μm) and 650 nm laser, the sensor exhibits the RI sensitivity of 7.48 V/RIU. The simple sensor structure and inexpensive demodulation method can make this technology for online refractive index measurement in widespread areas.

Wireless body sensor networks for health-monitoring applications.

PubMed

Hao, Yang; Foster, Robert

2008-11-01

Current wireless technologies, such as wireless body area networks and wireless personal area networks, provide promising applications in medical monitoring systems to measure specified physiological data and also provide location-based information, if required. With the increasing sophistication of wearable and implantable medical devices and their integration with wireless sensors, an ever-expanding range of therapeutic and diagnostic applications is being pursued by research and commercial organizations. This paper aims to provide a comprehensive review of recent developments in wireless sensor technology for monitoring behaviour related to human physiological responses. It presents background information on the use of wireless technology and sensors to develop a wireless physiological measurement system. A generic miniature platform and other available technologies for wireless sensors have been studied in terms of hardware and software structural requirements for a low-cost, low-power, non-invasive and unobtrusive system.

Mobile Carbon Monoxide Monitoring System Based on Arduino-Matlab for Environmental Monitoring Application

NASA Astrophysics Data System (ADS)

Azieda Mohd Bakri, Nur; Junid, Syed Abdul Mutalib Al; Razak, Abdul Hadi Abdul; Idros, Mohd Faizul Md; Karimi Halim, Abdul

2015-11-01

Nowadays, the increasing level of carbon monoxide globally has become a serious environmental issue which has been highlighted in most of the country globally. The monitoring of carbon monoxide content is one of the approaches to identify the level of carbon monoxide pollution towards providing the solution for control the level of carbon monoxide produced. Thus, this paper proposed a mobile carbon monoxide monitoring system for measuring the carbon monoxide content based on Arduino-Matlab General User Interface (GUI). The objective of this project is to design, develop and implement the real-time mobile carbon monoxide sensor system and interfacing for measuring the level of carbon monoxide contamination in real environment. Four phases or stages of work have been carried out for the accomplishment of the project, which classified as sensor development, controlling and integrating sensor, data collection and data analysis. As a result, a complete design and developed system has been verified with the handheld industrial standard carbon monoxide sensor for calibrating the sensor sensitivity and measurement in the laboratory. Moreover, the system has been tested in real environments by measuring the level of carbon monoxide in three different lands used location; industrial area; residential area and main road (commercial area). In this real environment test, the industrial area recorded the highest reading with 71.23 ppm and 82.59 ppm for sensor 1 and sensor 2 respectively. As a conclusion, the mobile realtime carbon monoxide system based on the Arduino-Matlab is the best approach to measure the carbon monoxide concentration in different land-used since it does not require a manual data collection and reduce the complexity of the existing carbon monoxide level concentration measurement practise at the same time with a complete data analysis facilities.

Site characterization and analysis penetrometer system

NASA Astrophysics Data System (ADS)

Heath, Jeff

1995-04-01

The site characterization and analysis penetrometer system (SCAPS) with laser induced fluorescence (LIF) sensors is being demonstrated as a quick field screening technique to determine the physical and chemical characteristics of subsurface soil and contaminants at hazardous waste sites SCAPS is a collaborative development effort of the Navy, Army, and Air Force under the Tri-Service SCAPS Program. The current SCAPS configuration is designed to quickly and cost-effectively distinguish areas contaminated with petroleum products (hydrocarbons) from unaffected areas.

Optical sensor array platform based on polymer electronic devices

NASA Astrophysics Data System (ADS)

Koetse, Marc M.; Rensing, Peter A.; Sharpe, Ruben B. A.; van Heck, Gert T.; Allard, Bart A. M.; Meulendijks, Nicole N. M. M.; Kruijt, Peter G. M.; Tijdink, Marcel W. W. J.; De Zwart, René M.; Houben, René J.; Enting, Erik; van Veen, Sjaak J. J. F.; Schoo, Herman F. M.

2007-10-01

Monitoring of personal wellbeing and optimizing human performance are areas where sensors have only begun to be used. One of the reasons for this is the specific demands that these application areas put on the underlying technology and system properties. In many cases these sensors will be integrated in clothing, be worn on the skin, or may even be placed inside the body. This implies that flexibility and wearability of the systems is essential for their success. Devices based on polymer semiconductors allow for these demands since they can be fabricated with thin film technology. The use of thin film device technology allows for the fabrication of very thin sensors (e.g. integrated in food product packaging), flexible or bendable sensors in wearables, large area/distributed sensors, and intrinsically low-cost applications in disposable products. With thin film device technology a high level of integration can be achieved with parts that analyze signals, process and store data, and interact over a network. Integration of all these functions will inherently lead to better cost/performance ratios, especially if printing and other standard polymer technology such as high precision moulding is applied for the fabrication. In this paper we present an optical transmission sensor array based on polymer semiconductor devices made by thin film technology. The organic devices, light emitting diodes, photodiodes and selective medium chip, are integrated with classic electronic components. Together they form a versatile sensor platform that allows for the quantitative measurement of 100 channels and communicates wireless with a computer. The emphasis is given to the sensor principle, the design, fabrication technology and integration of the thin film devices.

Sensing Models and Sensor Network Architectures for Transport Infrastructure Monitoring in Smart Cities

NASA Astrophysics Data System (ADS)

Simonis, Ingo

2015-04-01

Transport infrastructure monitoring and analysis is one of the focus areas in the context of smart cities. With the growing number of people moving into densely populated urban metro areas, precise tracking of moving people and goods is the basis for profound decision-making and future planning. With the goal of defining optimal extensions and modifications to existing transport infrastructures, multi-modal transport has to be monitored and analysed. This process is performed on the basis of sensor networks that combine a variety of sensor models, types, and deployments within the area of interest. Multi-generation networks, consisting of a number of sensor types and versions, are causing further challenges for the integration and processing of sensor observations. These challenges are not getting any smaller with the development of the Internet of Things, which brings promising opportunities, but is currently stuck in a type of protocol war between big industry players from both the hardware and network infrastructure domain. In this paper, we will highlight how the OGC suite of standards, with the Sensor Web standards developed by the Sensor Web Enablement Initiative together with the latest developments by the Sensor Web for Internet of Things community can be applied to the monitoring and improvement of transport infrastructures. Sensor Web standards have been applied in the past to pure technical domains, but need to be broadened now in order to meet new challenges. Only cross domain approaches will allow to develop satisfying transport infrastructure approaches that take into account requirements coming form a variety of sectors such as tourism, administration, transport industry, emergency services, or private people. The goal is the development of interoperable components that can be easily integrated within data infrastructures and follow well defined information models to allow robust processing.

Adaptation of ion beam technology to microfabrication of solid state devices and transducers

NASA Technical Reports Server (NTRS)

Topich, J. A.

1977-01-01

It was found that ion beam texturing of silicon surfaces can be used to increase the effective surface area of MOS capacitors. There is, however, a problem with low dielectric breakdown. Preliminary work was begun on the fabrication of ion implanted resistors on textured surfaces and the potential improvement of wire bond strength by bonding to a textured surface. In the area of ion beam sputtering, the techniques for sputtering PVC were developed. A PVC target containing valinomycin was used to sputter an ion selective membrane on a field effect transistor to form a potassium ion sensor.

Fabrication of a Horizontal and a Vertical Large Surface Area Nanogap Electrochemical Sensor

PubMed Central

Hammond, Jules L.; Rosamond, Mark C.; Sivaraya, Siva; Marken, Frank; Estrela, Pedro

2016-01-01

Nanogap sensors have a wide range of applications as they can provide accurate direct detection of biomolecules through impedimetric or amperometric signals. Signal response from nanogap sensors is dependent on both the electrode spacing and surface area. However, creating large surface area nanogap sensors presents several challenges during fabrication. We show two different approaches to achieve both horizontal and vertical coplanar nanogap geometries. In the first method we use electron-beam lithography (EBL) to pattern an 11 mm long serpentine nanogap (215 nm) between two electrodes. For the second method we use inductively-coupled plasma (ICP) reactive ion etching (RIE) to create a channel in a silicon substrate, optically pattern a buried 1.0 mm × 1.5 mm electrode before anodically bonding a second identical electrode, patterned on glass, directly above. The devices have a wide range of applicability in different sensing techniques with the large area nanogaps presenting advantages over other devices of the same family. As a case study we explore the detection of peptide nucleic acid (PNA)−DNA binding events using dielectric spectroscopy with the horizontal coplanar device. PMID:27983655

Leica ADS40 Sensor for Coastal Multispectral Imaging

NASA Technical Reports Server (NTRS)

Craig, John C.

2007-01-01

The Leica ADS40 Sensor as it is used for coastal multispectral imaging is presented. The contents include: 1) Project Area Overview; 2) Leica ADS40 Sensor; 3) Focal Plate Arrangements; 4) Trichroid Filter; 5) Gradient Correction; 6) Image Acquisition; 7) Remote Sensing and ADS40; 8) Band comparisons of Satellite and Airborne Sensors; 9) Impervious Surface Extraction; and 10) Impervious Surface Details.

Wide area detection system: Conceptual design study. [using television and microelectronic technology

NASA Technical Reports Server (NTRS)

Hilbert, E. E.; Carl, C.; Goss, W.; Hansen, G. R.; Olsasky, M. J.; Johnston, A. R.

1978-01-01

An integrated sensor for traffic surveillance on mainline sections of urban freeways is described. Applicable imaging and processor technology is surveyed and the functional requirements for the sensors and the conceptual design of the breadboard sensors are given. Parameters measured by the sensors include lane density, speed, and volume. The freeway image is also used for incident diagnosis.

Optical fiber bundle displacement sensor using an ac-modulated light source with subnanometer resolution and low thermal drift

NASA Astrophysics Data System (ADS)

Shimamoto, Atsushi; Tanaka, Kohichi

1995-09-01

An optical fiber bundle displacement sensor with subnanometer order resolution and low thermal drift is proposed. The setup is based on a carrier amplifier system and involves techniques to eliminate fluctuation in the light power of the source. The achieved noise level of the sensor was 0.03 nm/ \\radical Hz \\end-radical . The stability was estimated by comparing the outputs of two different sensors from the same target for 4 ks (67 min). The relative displacements between the fiber bundle ends of the two sensors and the target surface varied in the area of 400 nm depending on the ambient temperature variation at 2 deg C. However, the difference in output between the two sensor systems is within 2 nm for more than 1 hour of measurement. It is expected that it would be reduced to within the area of 0.1 nm if the ambient temperature were controlled to within +/-0.1 deg C. It is concluded that the stability of the sensors is sufficiently good to be used with nanotechnological instruments.

Census Cities Project and atlas of urban and regional change

NASA Technical Reports Server (NTRS)

Wray, J. R.

1970-01-01

The research design and imagery utilization for urban applications of remote sensing are reviewed, including the combined use of sensor and census data and aircraft and spacecraft sensor platforms. The related purposes of the Census Cities Project are elucidated: (1) to assess the role of remote sensors on high altitude platforms for comparative study of urban areas; (2) to detect changes in selected U.S. urban areas between the 1970 census and the time of launching of an earth-orbiting sensor platform prior to next census; (3) to test the satellite sensor platform utility to monitor urban change and serve as a control for sensor image interpretation; (4) to design an information system for incorporating graphic sensor data with census-type data gathered by traditional techniques; (5) to identify and to design user-oriented end-products or information services; and (6) to ascertain what organizational capability would be needed to provide such services on a continuing basis. A need to develop not only a spatial data information system, but also a methodology for detecting and interpreting change is implied.

Investigation of a fiber optic surface plasmon spectroscopy in conjunction with conductivity as an in situ method for simultaneously monitoring changes in dissolved organic carbon and salinity in coastal waters.

PubMed

Kim, Yoon-Chang; Cramer, Jeffrey A; Booksh, Karl S

2011-10-21

A combination surface plasmon resonance (SPR) and conductivity sensor array was developed and implemented to demonstrate the ability to differentiate among changes in dissolved organic carbon (DOC) and salinity in coastal water. The array is capable of achieving sufficient spatial and temporal data density to better understand the cycling and fate of terrestrial DOC in coastal areas. DOC is the second largest source of bioreactive carbon in the environment and plays a key role in mediating microbial activity and generation of atmospheric CO(2). In the coastal areas, the salinity is also an important property in many applications, such as leak detection for landfill liners, saltwater intrusion to drinking water, marine environment monitoring, and seasonal climate prediction. Conductivity sensors are the industry standard for determining salinity in ocean systems. However, both conductivity and refractive index sensors, such as SPR spectroscopy based sensors, respond to salinity and DOC levels. To demonstrate the capability of the SPR sensor and a conductivity sensor to collect complimentary data useful in discrimination of salinity and DOC in coastal zone water, conductivity, SPR, and temperature data were collected during passage from the Juan de Fuca ridge area returning to the University of Washington docks.

Design of Secure ECG-Based Biometric Authentication in Body Area Sensor Networks

PubMed Central

Peter, Steffen; Pratap Reddy, Bhanu; Momtaz, Farshad; Givargis, Tony

2016-01-01

Body area sensor networks (BANs) utilize wireless communicating sensor nodes attached to a human body for convenience, safety, and health applications. Physiological characteristics of the body, such as the heart rate or Electrocardiogram (ECG) signals, are promising means to simplify the setup process and to improve security of BANs. This paper describes the design and implementation steps required to realize an ECG-based authentication protocol to identify sensor nodes attached to the same human body. Therefore, the first part of the paper addresses the design of a body-area sensor system, including the hardware setup, analogue and digital signal processing, and required ECG feature detection techniques. A model-based design flow is applied, and strengths and limitations of each design step are discussed. Real-world measured data originating from the implemented sensor system are then used to set up and parametrize a novel physiological authentication protocol for BANs. The authentication protocol utilizes statistical properties of expected and detected deviations to limit the number of false positive and false negative authentication attempts. The result of the described holistic design effort is the first practical implementation of biometric authentication in BANs that reflects timing and data uncertainties in the physical and cyber parts of the system. PMID:27110785

Design of Secure ECG-Based Biometric Authentication in Body Area Sensor Networks.

PubMed

Peter, Steffen; Reddy, Bhanu Pratap; Momtaz, Farshad; Givargis, Tony

2016-04-22

Body area sensor networks (BANs) utilize wireless communicating sensor nodes attached to a human body for convenience, safety, and health applications. Physiological characteristics of the body, such as the heart rate or Electrocardiogram (ECG) signals, are promising means to simplify the setup process and to improve security of BANs. This paper describes the design and implementation steps required to realize an ECG-based authentication protocol to identify sensor nodes attached to the same human body. Therefore, the first part of the paper addresses the design of a body-area sensor system, including the hardware setup, analogue and digital signal processing, and required ECG feature detection techniques. A model-based design flow is applied, and strengths and limitations of each design step are discussed. Real-world measured data originating from the implemented sensor system are then used to set up and parametrize a novel physiological authentication protocol for BANs. The authentication protocol utilizes statistical properties of expected and detected deviations to limit the number of false positive and false negative authentication attempts. The result of the described holistic design effort is the first practical implementation of biometric authentication in BANs that reflects timing and data uncertainties in the physical and cyber parts of the system.

Design and construction of smart cane using infrared laser-based tracking system

NASA Astrophysics Data System (ADS)

Wong, Chi Fung; Phitagragsakul, Narikorn; Jornsamer, Patcharaporn; Kaewmeesri, Pimsin; Jantakot, Pimsunan; Locharoenrat, Kitsakorn

2018-06-01

Our work is aimed to design and construct the smart cane. The infrared laser-based sensor was used as a distance detector and Arduino board was used as a microcontroller. On the other hand, Bluetooth was used as a wireless communicator and MP3 module together with the headset were used as a voice alert player. Our smart cane is a very effective device for the users under the indoor guidance. That is, the obstacle was detectable 3,000 cm away from the blind people. The white cane was assembled with the laser distance sensor and distance alert sensor served as the compact and light-weight device. Distance detection was very fast and precise when the smart cane was tested for the different obstacles, such as human, wall and wooden table under the indoor area.

Implantable self-reset CMOS image sensor and its application to hemodynamic response detection in living mouse brain

NASA Astrophysics Data System (ADS)

Yamaguchi, Takahiro; Takehara, Hiroaki; Sunaga, Yoshinori; Haruta, Makito; Motoyama, Mayumi; Ohta, Yasumi; Noda, Toshihiko; Sasagawa, Kiyotaka; Tokuda, Takashi; Ohta, Jun

2016-04-01

A self-reset pixel of 15 × 15 µm2 with high signal-to-noise ratio (effective peak SNR ≃64 dB) for an implantable image sensor has been developed for intrinsic signal detection arising from hemodynamic responses in a living mouse brain. For detecting local conversion between oxyhemoglobin (HbO) and deoxyhemoglobin (HbR) in brain tissues, an implantable imaging device was fabricated with our newly designed self-reset image sensor and orange light-emitting diodes (LEDs; λ = 605 nm). We demonstrated imaging of hemodynamic responses in the sensory cortical area accompanied by forelimb stimulation of a living mouse. The implantable imaging device for intrinsic signal detection is expected to be a powerful tool to measure brain activities in living animals used in behavioral analysis.

Technology for robotic surface inspection in space

NASA Technical Reports Server (NTRS)

Volpe, Richard; Balaram, J.

1994-01-01

This paper presents on-going research in robotic inspection of space platforms. Three main areas of investigation are discussed: machine vision inspection techniques, an integrated sensor end-effector, and an orbital environment laboratory simulation. Machine vision inspection utilizes automatic comparison of new and reference images to detect on-orbit induced damage such as micrometeorite impacts. The cameras and lighting used for this inspection are housed in a multisensor end-effector, which also contains a suite of sensors for detection of temperature, gas leaks, proximity, and forces. To fully test all of these sensors, a realistic space platform mock-up has been created, complete with visual, temperature, and gas anomalies. Further, changing orbital lighting conditions are effectively mimicked by a robotic solar simulator. In the paper, each of these technology components will be discussed, and experimental results are provided.

Automatic integration of data from dissimilar sensors

NASA Astrophysics Data System (ADS)

Citrin, W. I.; Proue, R. W.; Thomas, J. W.

The present investigation is concerned with the automatic integration of radar and electronic support measures (ESM) sensor data, and with the development of a method for the automatical integration of identification friend or foe (IFF) and radar sensor data. On the basis of the two considered proojects, significant advances have been made in the areas of sensor data integration. It is pointed out that the log likelihood approach in sensor data correlation is appropriate for both similar and dissimilar sensor data. Attention is given to the real time integration of radar and ESM sensor data, and a radar ESM correlation simulation program.

Compact survey and inspection day/night image sensor suite for small unmanned aircraft systems (EyePod)

NASA Astrophysics Data System (ADS)

Bird, Alan; Anderson, Scott A.; Linne von Berg, Dale; Davidson, Morgan; Holt, Niel; Kruer, Melvin; Wilson, Michael L.

2010-04-01

EyePod is a compact survey and inspection day/night imaging sensor suite for small unmanned aircraft systems (UAS). EyePod generates georeferenced image products in real-time from visible near infrared (VNIR) and long wave infrared (LWIR) imaging sensors and was developed under the ONR funded FEATHAR (Fusion, Exploitation, Algorithms, and Targeting for High-Altitude Reconnaissance) program. FEATHAR is being directed and executed by the Naval Research Laboratory (NRL) in conjunction with the Space Dynamics Laboratory (SDL) and FEATHAR's goal is to develop and test new tactical sensor systems specifically designed for small manned and unmanned platforms (payload weight < 50 lbs). The EyePod suite consists of two VNIR/LWIR (day/night) gimbaled sensors that, combined, provide broad area survey and focused inspection capabilities. Each EyePod sensor pairs an HD visible EO sensor with a LWIR bolometric imager providing precision geo-referenced and fully digital EO/IR NITFS output imagery. The LWIR sensor is mounted to a patent-pending jitter-reduction stage to correct for the high-frequency motion typically found on small aircraft and unmanned systems. Details will be presented on both the wide-area and inspection EyePod sensor systems, their modes of operation, and results from recent flight demonstrations.

An Outline of Data Aggregation Security in Heterogeneous Wireless Sensor Networks.

PubMed

Boubiche, Sabrina; Boubiche, Djallel Eddine; Bilami, Azzedine; Toral-Cruz, Homero

2016-04-12

Data aggregation processes aim to reduce the amount of exchanged data in wireless sensor networks and consequently minimize the packet overhead and optimize energy efficiency. Securing the data aggregation process is a real challenge since the aggregation nodes must access the relayed data to apply the aggregation functions. The data aggregation security problem has been widely addressed in classical homogeneous wireless sensor networks, however, most of the proposed security protocols cannot guarantee a high level of security since the sensor node resources are limited. Heterogeneous wireless sensor networks have recently emerged as a new wireless sensor network category which expands the sensor nodes' resources and capabilities. These new kinds of WSNs have opened new research opportunities where security represents a most attractive area. Indeed, robust and high security level algorithms can be used to secure the data aggregation at the heterogeneous aggregation nodes which is impossible in classical homogeneous WSNs. Contrary to the homogeneous sensor networks, the data aggregation security problem is still not sufficiently covered and the proposed data aggregation security protocols are numberless. To address this recent research area, this paper describes the data aggregation security problem in heterogeneous wireless sensor networks and surveys a few proposed security protocols. A classification and evaluation of the existing protocols is also introduced based on the adopted data aggregation security approach.

Community Air Sensor Network (CAIRSENSE) Project: Lower Cost, Continuous Ambient Monitoring Methods

EPA Science Inventory

Advances in air pollution sensor technology have enabled the development of small and low cost systems to measure outdoor air pollution. The deployment of numerous sensors across a small geographic area would have potential benefits to supplement existing monitoring networks and ...

Flexible three-dimensional electrochemical glucose sensor with improved sensitivity realized in hybrid polymer microelectromechanical systems technique.

PubMed

Patel, Jasbir N; Gray, Bonnie L; Kaminska, Bozena; Gates, Byron D

2011-09-01

Continuous glucose monitoring for patients with diabetes is of paramount importance to avoid severe health conditions resulting from hypoglycemia or hyperglycemia. Most available methods require an invasive setup and a health care professional. Handheld devices available on the market also require finger pricking for every measurement and do not provide continuous monitoring. Hence, continuous glucose monitoring from human tears using a glucose sensor embedded in a contact lens has been considered as a suitable option. However, the glucose concentration in human tears is very low in comparison with the blood glucose level (1/10-1/40 concentration). We propose a sensor that solves the sensitivity problem in a new way, is flexible, and is constructed onto the oxygen permeable contact lens material. To achieve such sensitivity while maintaining a small sensor footprint suitable for placement in a contact lens, we increased the active electrode area by using three-dimensional (3-D) electrode micropatterning. Fully flexible 3-D electrodes were realized utilizing ordered arrays of pillars with different shapes and heights. We successfully fabricated square and cylindrical pillars with different height (50, 100, and 200 μm) and uniform metal coverage to realize sensor electrodes. The increased surface area produces high amperometric current that increases sensor sensitivity up to 300% using 200 μm tall square pillars. The sensitivity improvement closely follows the improvement in the surface area of the electrode. The proposed flexible glucose sensors with 3-D microstructure electrodes are more sensitive to lower glucose concentrations and generate higher current signal than conventional glucose sensors. © 2011 Diabetes Technology Society.

A Fuzzy-Based Approach for Sensing, Coding and Transmission Configuration of Visual Sensors in Smart City Applications

PubMed Central

Costa, Daniel G.; Collotta, Mario; Pau, Giovanni; Duran-Faundez, Cristian

2017-01-01

The advance of technologies in several areas has allowed the development of smart city applications, which can improve the way of life in modern cities. When employing visual sensors in that scenario, still images and video streams may be retrieved from monitored areas, potentially providing valuable data for many applications. Actually, visual sensor networks may need to be highly dynamic, reflecting the changing of parameters in smart cities. In this context, characteristics of visual sensors and conditions of the monitored environment, as well as the status of other concurrent monitoring systems, may affect how visual sensors collect, encode and transmit information. This paper proposes a fuzzy-based approach to dynamically configure the way visual sensors will operate concerning sensing, coding and transmission patterns, exploiting different types of reference parameters. This innovative approach can be considered as the basis for multi-systems smart city applications based on visual monitoring, potentially bringing significant results for this research field. PMID:28067777

A Fuzzy-Based Approach for Sensing, Coding and Transmission Configuration of Visual Sensors in Smart City Applications.

PubMed

Costa, Daniel G; Collotta, Mario; Pau, Giovanni; Duran-Faundez, Cristian

2017-01-05

The advance of technologies in several areas has allowed the development of smart city applications, which can improve the way of life in modern cities. When employing visual sensors in that scenario, still images and video streams may be retrieved from monitored areas, potentially providing valuable data for many applications. Actually, visual sensor networks may need to be highly dynamic, reflecting the changing of parameters in smart cities. In this context, characteristics of visual sensors and conditions of the monitored environment, as well as the status of other concurrent monitoring systems, may affect how visual sensors collect, encode and transmit information. This paper proposes a fuzzy-based approach to dynamically configure the way visual sensors will operate concerning sensing, coding and transmission patterns, exploiting different types of reference parameters. This innovative approach can be considered as the basis for multi-systems smart city applications based on visual monitoring, potentially bringing significant results for this research field.

Method for remote detection of trace contaminants

DOEpatents

Simonson, Robert J.; Hance, Bradley G.

2003-09-09

A method for remote detection of trace contaminants in a target area comprises applying sensor particles that preconcentrate the trace contaminant to the target area and detecting the contaminant-sensitive fluorescence from the sensor particles. The sensor particles can have contaminant-sensitive and contaminant-insensitive fluorescent compounds to enable the determination of the amount of trace contaminant present in the target are by relative comparison of the emission of the fluorescent compounds by a local or remote fluorescence detector. The method can be used to remotely detect buried minefields.

Oxygen sensor for monitoring gas mixtures containing hydrocarbons

DOEpatents

Ruka, Roswell J.; Basel, Richard A.

1996-01-01

A gas sensor measures O.sub.2 content of a reformable monitored gas containing hydrocarbons H.sub.2 O and/or CO.sub.2, preferably in association with an electrochemical power generation system. The gas sensor has a housing communicating with the monitored gas environment and carries the monitored gas through an integral catalytic hydrocarbon reforming chamber containing a reforming catalyst, and over a solid electrolyte electrochemical cell used for sensing purposes. The electrochemical cell includes a solid electrolyte between a sensor electrode that is exposed to the monitored gas, and a reference electrode that is isolated in the housing from the monitored gas and is exposed to a reference gas environment. A heating element is also provided in heat transfer communication with the gas sensor. A circuit that can include controls operable to adjust operations via valves or the like is connected between the sensor electrode and the reference electrode to process the electrical signal developed by the electrochemical cell. The electrical signal varies as a measure of the equilibrium oxygen partial pressure of the monitored gas. Signal noise is effectively reduced by maintaining a constant temperature in the area of the electrochemical cell and providing a monitored gas at chemical equilibria when contacting the electrochemical cell. The output gas from the electrochemical cell of the sensor is fed back into the conduits of the power generating system.

Oxygen sensor for monitoring gas mixtures containing hydrocarbons

DOEpatents

Ruka, R.J.; Basel, R.A.

1996-03-12

A gas sensor measures O{sub 2} content of a reformable monitored gas containing hydrocarbons, H{sub 2}O and/or CO{sub 2}, preferably in association with an electrochemical power generation system. The gas sensor has a housing communicating with the monitored gas environment and carries the monitored gas through an integral catalytic hydrocarbon reforming chamber containing a reforming catalyst, and over a solid electrolyte electrochemical cell used for sensing purposes. The electrochemical cell includes a solid electrolyte between a sensor electrode that is exposed to the monitored gas, and a reference electrode that is isolated in the housing from the monitored gas and is exposed to a reference gas environment. A heating element is also provided in heat transfer communication with the gas sensor. A circuit that can include controls operable to adjust operations via valves or the like is connected between the sensor electrode and the reference electrode to process the electrical signal developed by the electrochemical cell. The electrical signal varies as a measure of the equilibrium oxygen partial pressure of the monitored gas. Signal noise is effectively reduced by maintaining a constant temperature in the area of the electrochemical cell and providing a monitored gas at chemical equilibria when contacting the electrochemical cell. The output gas from the electrochemical cell of the sensor is fed back into the conduits of the power generating system. 4 figs.

View angle effects on relationships between leaf area index in wheat and vegetation indices

NASA Astrophysics Data System (ADS)

Chen, H.; Li, W.; Huang, W.; Niu, Z.

2016-12-01

The effects of plant types and view angles on the canopy-reflected spectrum can not be ignored in the estimation of leaf area index (LAI) using remote sensing vegetation indices. While vegetation indices derived from nadir-viewing remote sensors are insufficient in leaf area index (LAI) estimation because of its misinterpretation of structural characteristecs, vegetation indices derived from multi-angular remote sensors have potential to improve detection of LAI. However, view angle effects on relationships between these indices and LAI for low standing crops (i.e. wheat) has not been fully evaluated and thus limits them to applied for consistent and accurate monitoring of vegetation. View angles effects of two types of winter wheat (wheat 411, erectophile; and wheat 9507, planophile) on relationship between LAI and spectral reflectance are assessed and compared in this study. An evaluation is conducted with in-situ measurements of LAI and bidirectional reflectance in the principal plane from -60° (back-scattering direction ) ot 60° (forward scattering direction) in the growth cycle of winter wheat. A variety of vegetation indices (VIs) published are calculated by BRDF. Additionally, all combinations of the bands are used in order to calculate Normalized difference Spectral Indices (NDSI) and Simple Subtraction Indices (SSI). The performance of the above indices along with raw reflectance and reflectance derivatives on LAI estimation are examined based on a linearity comparison. The results will be helpful in further developing multi-angle remote sensing models for accurate LAI evaluation.

Informatics for multi-disciplinary ocean sciences

NASA Astrophysics Data System (ADS)

Pearlman, Jay; Delory, Eric; Pissierssens, Peter; Raymond, Lisa; Simpson, Pauline; Waldmann, Christoph; Williams 3rd, Albert; Yoder, Jim

2014-05-01

Ocean researchers must work across disciplines to provide clear and understandable assessments of the state of the ocean. With advances in technology, not only in observation, but also communication and computer science, we are in a new era where we can answer questions at the time and space scales that are relevant to our state of the art research needs. This presentation will address three areas of the informatics of the end-to-end process: sensors and information extraction in the sensing environment; using diverse data for understanding selected ocean processes; and supporting open data initiatives. A National Science Foundation funded Ocean Observations Research Coordination Network (RCN) is addressing these areas from the perspective of improving interdisciplinary research. The work includes an assessment of Open Data Access with a paper in preparation. Interoperability and sensors is a new activity that couples with European projects, COOPEUS and NeXOS, in looking at sensors and related information systems for a new generation of measurement capability. A working group on synergies of in-situ and satellite remote sensing is analyzing approaches for more effective use of these measurements. This presentation will examine the steps forward for data exchange and for addressing gaps in communication and informatics.

A flexible dual-mode proximity sensor based on cooperative sensing for robot skin applications

NASA Astrophysics Data System (ADS)

Huang, Ying; Cai, Xia; Kan, Wenqing; Qiu, Shihua; Guo, Xiaohui; Liu, Caixia; Liu, Ping

2017-08-01

A flexible dual-mode proximity sensor has been designed and implemented, which is capable of combining capacitive-resistive detection in this paper. The capacitive type proximity sensor detecting is defined as mode-C, and the resistive type proximity sensor detecting is defined as mode-R. The characteristics of the proximity sensor are as follows: (1) the theoretical mode is developed which indicates that this proximity sensor can reflect proximity information accurately; (2) both sensing modes are vertically integrated into a sandwich-like chip with an 8 mm × 12 mm unit area. The thickness of a mode-R sensing material (graphene nanoplatelets) and mode-C dielectric (the mixture of carbon black and silicone rubber) is 1 mm and 2.5 mm, respectively; (3) for mode-R, the linearity of temperature-resistance curve can achieve 0.998 in the temperature range from 25°C to 65°C. And for mode-C, various materials can be successfully detected with fast response and high reversibility. Meanwhile, the study compensated the influence of object temperature to ensure mode-C properly works. A cooperative sensing test shows that R-C dual modes sense effectively which can enlarge the sensing distance compared with the single mode proximity sensor. The fabrication of this sensor is convenient, and the integrity of a flexible sandwich-like structure based on dual modes is beneficial to form arrays, which is suitable to be used in skin-like sensing applications.

Recent progress in graphene-material-based optical sensors.

PubMed

Deng, Xianghua; Tang, Hao; Jiang, Jianhui

2014-11-01

Graphene material has been widely used for optical sensors owing to its excellent properties, including high-energy transfer efficiency, large surface area, and great biocompatibility. Different analytes such as nucleic acids, proteins, and small molecules can be detected by graphene-material-based optical sensors. This review provides a comprehensive discussion of graphene-material-based optical sensors focusing on detection mechanisms and biosensor designs. Challenges and future perspectives for graphene-material-based optical sensors are also presented.

Faulty node detection in wireless sensor networks using a recurrent neural network

NASA Astrophysics Data System (ADS)

Atiga, Jamila; Mbarki, Nour Elhouda; Ejbali, Ridha; Zaied, Mourad

2018-04-01

The wireless sensor networks (WSN) consist of a set of sensors that are more and more used in surveillance applications on a large scale in different areas: military, Environment, Health ... etc. Despite the minimization and the reduction of the manufacturing costs of the sensors, they can operate in places difficult to access without the possibility of reloading of battery, they generally have limited resources in terms of power of emission, of processing capacity, data storage and energy. These sensors can be used in a hostile environment, such as, for example, on a field of battle, in the presence of fires, floods, earthquakes. In these environments the sensors can fail, even in a normal operation. It is therefore necessary to develop algorithms tolerant and detection of defects of the nodes for the network of sensor without wires, therefore, the faults of the sensor can reduce the quality of the surveillance if they are not detected. The values that are measured by the sensors are used to estimate the state of the monitored area. We used the Non-linear Auto- Regressive with eXogeneous (NARX), the recursive architecture of the neural network, to predict the state of a node of a sensor from the previous values described by the functions of time series. The experimental results have verified that the prediction of the State is enhanced by our proposed model.

Unobtrusive Monitoring of Neonatal Brain Temperature Using a Zero-Heat-Flux Sensor Matrix.

PubMed

Atallah, Louis; Bongers, Edwin; Lamichhane, Bishal; Bambang-Oetomo, Sidarto

2016-01-01

The temperature of preterm neonates must be maintained within a narrow window to ensure their survival. Continuously measuring their core temperature provides an optimal means of monitoring their thermoregulation and their response to environmental changes. However, existing methods of measuring core temperature can be very obtrusive, such as rectal probes, or inaccurate/lagging, such as skin temperature sensors and spot-checks using tympanic temperature sensors. This study investigates an unobtrusive method of measuring brain temperature continuously using an embedded zero-heat-flux (ZHF) sensor matrix placed under the head of the neonate. The measured temperature profile is used to segment areas of motion and incorrect positioning, where the neonate's head is not above the sensors. We compare our measurements during low motion/stable periods to esophageal temperatures for 12 preterm neonates, measured for an average of 5 h per neonate. The method we propose shows good correlation with the reference temperature for most of the neonates. The unobtrusive embedding of the matrix in the neonate's environment poses no harm or disturbance to the care work-flow, while measuring core temperature. To address the effect of motion on the ZHF measurements in the current embodiment, we recommend a more ergonomic embedding ensuring the sensors are continuously placed under the neonate's head.

Organic-on-silicon complementary metal-oxide-semiconductor colour image sensors.

PubMed

Lim, Seon-Jeong; Leem, Dong-Seok; Park, Kyung-Bae; Kim, Kyu-Sik; Sul, Sangchul; Na, Kyoungwon; Lee, Gae Hwang; Heo, Chul-Joon; Lee, Kwang-Hee; Bulliard, Xavier; Satoh, Ryu-Ichi; Yagi, Tadao; Ro, Takkyun; Im, Dongmo; Jung, Jungkyu; Lee, Myungwon; Lee, Tae-Yon; Han, Moon Gyu; Jin, Yong Wan; Lee, Sangyoon

2015-01-12

Complementary metal-oxide-semiconductor (CMOS) colour image sensors are representative examples of light-detection devices. To achieve extremely high resolutions, the pixel sizes of the CMOS image sensors must be reduced to less than a micron, which in turn significantly limits the number of photons that can be captured by each pixel using silicon (Si)-based technology (i.e., this reduction in pixel size results in a loss of sensitivity). Here, we demonstrate a novel and efficient method of increasing the sensitivity and resolution of the CMOS image sensors by superposing an organic photodiode (OPD) onto a CMOS circuit with Si photodiodes, which consequently doubles the light-input surface area of each pixel. To realise this concept, we developed organic semiconductor materials with absorption properties selective to green light and successfully fabricated highly efficient green-light-sensitive OPDs without colour filters. We found that such a top light-receiving OPD, which is selective to specific green wavelengths, demonstrates great potential when combined with a newly designed Si-based CMOS circuit containing only blue and red colour filters. To demonstrate the effectiveness of this state-of-the-art hybrid colour image sensor, we acquired a real full-colour image using a camera that contained the organic-on-Si hybrid CMOS colour image sensor.

Organic-on-silicon complementary metal–oxide–semiconductor colour image sensors

PubMed Central

Lim, Seon-Jeong; Leem, Dong-Seok; Park, Kyung-Bae; Kim, Kyu-Sik; Sul, Sangchul; Na, Kyoungwon; Lee, Gae Hwang; Heo, Chul-Joon; Lee, Kwang-Hee; Bulliard, Xavier; Satoh, Ryu-Ichi; Yagi, Tadao; Ro, Takkyun; Im, Dongmo; Jung, Jungkyu; Lee, Myungwon; Lee, Tae-Yon; Han, Moon Gyu; Jin, Yong Wan; Lee, Sangyoon

2015-01-01

Complementary metal–oxide–semiconductor (CMOS) colour image sensors are representative examples of light-detection devices. To achieve extremely high resolutions, the pixel sizes of the CMOS image sensors must be reduced to less than a micron, which in turn significantly limits the number of photons that can be captured by each pixel using silicon (Si)-based technology (i.e., this reduction in pixel size results in a loss of sensitivity). Here, we demonstrate a novel and efficient method of increasing the sensitivity and resolution of the CMOS image sensors by superposing an organic photodiode (OPD) onto a CMOS circuit with Si photodiodes, which consequently doubles the light-input surface area of each pixel. To realise this concept, we developed organic semiconductor materials with absorption properties selective to green light and successfully fabricated highly efficient green-light-sensitive OPDs without colour filters. We found that such a top light-receiving OPD, which is selective to specific green wavelengths, demonstrates great potential when combined with a newly designed Si-based CMOS circuit containing only blue and red colour filters. To demonstrate the effectiveness of this state-of-the-art hybrid colour image sensor, we acquired a real full-colour image using a camera that contained the organic-on-Si hybrid CMOS colour image sensor. PMID:25578322

Development of a spatial decision support system for flood risk management in Brazil that combines volunteered geographic information with wireless sensor networks

NASA Astrophysics Data System (ADS)

Horita, Flávio E. A.; Albuquerque, João Porto de; Degrossi, Lívia C.; Mendiondo, Eduardo M.; Ueyama, Jó

2015-07-01

Effective flood risk management requires updated information to ensure that the correct decisions can be made. This can be provided by Wireless Sensor Networks (WSN) which are a low-cost means of collecting updated information about rivers. Another valuable resource is Volunteered Geographic Information (VGI) which is a comparatively new means of improving the coverage of monitored areas because it is able to supply supplementary information to the WSN and thus support decision-making in flood risk management. However, there still remains the problem of how to combine WSN data with VGI. In this paper, an attempt is made to investigate AGORA-DS, which is a Spatial Decision Support System (SDSS) that is able to make flood risk management more effective by combining these data sources, i.e. WSN with VGI. This approach is built over a conceptual model that complies with the interoperable standards laid down by the Open Geospatial Consortium (OGC) - e.g. Sensor Observation Service (SOS) and Web Feature Service (WFS) - and seeks to combine and present unified information in a web-based decision support tool. This work was deployed in a real scenario of flood risk management in the town of São Carlos in Brazil. The evidence obtained from this deployment confirmed that interoperable standards can support the integration of data from distinct data sources. In addition, they also show that VGI is able to provide information about areas of the river basin which lack data since there is no appropriate station in the area. Hence it provides a valuable support for the WSN data. It can thus be concluded that AGORA-DS is able to combine information provided by WSN and VGI, and provide useful information for supporting flood risk management.

Automated Image Intelligence Adaptive Sensor Management System for High Altitude Long Endurance UAVs in a Dynamic and Anti-Access Area Denial Environment

NASA Astrophysics Data System (ADS)

Kim, Gi Young

The problem we investigate deals with an Image Intelligence (IMINT) sensor allocation schedule for High Altitude Long Endurance UAVs in a dynamic and Anti-Access Area Denial (A2AD) environment. The objective is to maximize the Situational Awareness (SA) of decision makers. The value of SA can be improved in two different ways. First, if a sensor allocated to an Areas of Interest (AOI) detects target activity, then the SA value will be increased. Second, the SA value increases if an AOI is monitored for a certain period of time, regardless of target detections. These values are functions of the sensor allocation time, sensor type and mode. Relatively few studies in the archival literature have been devoted to an analytic, detailed explanation of the target detection process, and AOI monitoring value dynamics. These two values are the fundamental criteria used to choose the most judicious sensor allocation schedule. This research presents mathematical expressions for target detection processes, and shows the monitoring value dynamics. Furthermore, the dynamics of target detection is the result of combined processes between belligerent behavior (target activity) and friendly behavior (sensor allocation). We investigate these combined processes and derive mathematical expressions for simplified cases. These closed form mathematical models can be used for Measures of Effectiveness (MOEs), i.e., target activity detection to evaluate sensor allocation schedules. We also verify these models with discrete event simulations which can also be used to describe more complex systems. We introduce several methodologies to achieve a judicious sensor allocation schedule focusing on the AOI monitoring value. The first methodology is a discrete time integer programming model which provides an optimal solution but is impractical for real world scenarios due to its computation time. Thus, it is necessary to trade off the quality of solution with computation time. The Myopic Greedy Procedure (MGP) is a heuristic which chooses the largest immediate unit time return at each decision epoch. This reduces computation time significantly, but the quality of the solution may be only 95% of optimal (for small size problems). Another alternative is a multi-start random constructive Hybrid Myopic Greedy Procedure (H-MGP), which incorporates stochastic variation in choosing an action at each stage, and repeats it a predetermined number of times (roughly 99.3% of optimal with 1000 repetitions). Finally, the One Stage Look Ahead (OSLA) procedure considers all the 'top choices' at each stage for a temporary time horizon and chooses the best action (roughly 98.8% of optimal with no repetition). Using OSLA procedure, we can have ameliorated solutions within a reasonable computation time. Other important issues discussed in this research are methodologies for the development of input parameters for real world applications.

Ultrasensitive quartz crystal microbalance sensors for detection of M13-Phages in liquids.

PubMed

Uttenthaler, E; Schräml, M; Mandel, J; Drost, S

2001-12-01

Quartz crystal microbalance (QCM) sensors are widely used for determining liquid properties or probing interfacial processes. For some applications the sensitivity of the QCM sensors typically used (5-20 MHz) is limited compared with other biosensor methods. In this study ultrasensitive QCM sensors with resonant frequencies from 39 to 110 MHz for measurements in the liquid phase are presented. The fundamental sensor effect of a QCM is the decrease of the resonant frequency of an oscillating quartz crystal due to the binding of mass on a coated surface during the measurement. The sensitivity of QCM sensors increases strongly with an increasing resonant frequency and, therefore, with a decreasing thickness of the sensitive area. The new kind of ultrasensitive QCM sensors used in this study is based on chemically milled shear mode quartz crystals which are etched only in the center of the blank, forming a thin quartz membrane with a thick, mechanically stable outer ring. An immunoassay using a virus specific monoclonal antibody and a M13-Phage showed an increase in the signal to noise ratio by a factor of more than 6 for 56 MHz quartz crystals compared with standard 19 MHz quartz crystals, the detection limit was improved by a factor of 200. Probing of acoustic properties of glycerol/water mixtures resulted in an increase in sensitivity, which is in very good agreement with theory. Chemically milled QCM sensors strongly improve the sensitivity in biosensing and probing of acoustic properties and, therefore, offer interesting new application fields for QCM sensors.

High-Sensitivity Encoder-Like Micro Area-Changed Capacitive Transducer for a Nano-g Micro Accelerometer

PubMed Central

Zheng, Panpan; Liu, Jinquan; Li, Zhu; Liu, Huafeng

2017-01-01

Encoder-like micro area-changed capacitive transducers are advantageous in terms of their better linearity and larger dynamic range compared to gap-changed capacitive transducers. Such transducers have been widely applied in rectilinear and rotational position sensors, lab-on-a-chip applications and bio-sensors. However, a complete model accounting for both the parasitic capacitance and fringe effect in area-changed capacitive transducers has not yet been developed. This paper presents a complete model for this type of transducer applied to a high-resolution micro accelerometer that was verified by both simulations and experiments. A novel optimization method involving the insertion of photosensitive polyimide was used to reduce the parasitic capacitance, and the capacitor spacing was decreased to overcome the fringe effect. The sensitivity of the optimized transducer was approximately 46 pF/mm, which was nearly 40 times higher than that of our previous transducer. The displacement detection resolution was measured as 50 pm/√Hz at 0.1 Hz using a precise capacitance detection circuit. Then, the transducer was applied to a sandwich in-plane micro accelerometer, and the measured level of the accelerometer was approximately 30 ng/√Hz at 1Hz. The earthquake that occurred in Taiwan was also detected during a continuous gravity measurement. PMID:28930176

A Fatigue Measuring Protocol for Wireless Body Area Sensor Networks.

PubMed

Akram, Sana; Javaid, Nadeem; Ahmad, Ashfaq; Khan, Zahoor Ali; Imran, Muhammad; Guizani, Mohsen; Hayat, Amir; Ilahi, Manzoor

2015-12-01

As players and soldiers preform strenuous exercises and do difficult and tiring duties, they are usually the common victims of muscular fatigue. Keeping this in mind, we propose FAtigue MEasurement (FAME) protocol for soccer players and soldiers using in-vivo sensors for Wireless Body Area Sensor Networks (WBASNs). In FAME, we introduce a composite parameter for fatigue measurement by setting a threshold level for each sensor. Whenever, any sensed data exceeds its threshold level, the players or soldiers are declared to be in a state of fatigue. Moreover, we use a vibration pad for the relaxation of fatigued muscles, and then utilize the vibrational energy by means of vibration detection circuit to recharge the in-vivo sensors. The induction circuit achieves about 68 % link efficiency. Simulation results show better performance of the proposed FAME protocol, in the chosen scenarios, as compared to an existing Wireless Soccer Team Monitoring (WSTM) protocol in terms of the selected metrics.

Multi-Axis Force/Torque Sensor Based on Simply-Supported Beam and Optoelectronics

PubMed Central

Noh, Yohan; Bimbo, Joao; Sareh, Sina; Wurdemann, Helge; Fraś, Jan; Chathuranga, Damith Suresh; Liu, Hongbin; Housden, James; Althoefer, Kaspar; Rhode, Kawal

2016-01-01

This paper presents a multi-axis force/torque sensor based on simply-supported beam and optoelectronic technology. The sensor’s main advantages are: (1) Low power consumption; (2) low-level noise in comparison with conventional methods of force sensing (e.g., using strain gauges); (3) the ability to be embedded into different mechanical structures; (4) miniaturisation; (5) simple manufacture and customisation to fit a wide-range of robot systems; and (6) low-cost fabrication and assembly of sensor structure. For these reasons, the proposed multi-axis force/torque sensor can be used in a wide range of application areas including medical robotics, manufacturing, and areas involving human–robot interaction. This paper shows the application of our concept of a force/torque sensor to flexible continuum manipulators: A cylindrical MIS (Minimally Invasive Surgery) robot, and includes its design, fabrication, and evaluation tests. PMID:27869689

Wireless Sensing Opportunities for Aerospace Applications

NASA Technical Reports Server (NTRS)

Wilson, William; Atkinson, Gary

2007-01-01

Wireless sensors and sensor networks is an emerging technology area with many applications within the aerospace industry. Integrated vehicle health monitoring (IVHM) of aerospace vehicles is needed to ensure the safety of the crew and the vehicle, yet often high costs, weight, size and other constraints prevent the incorporation of instrumentation onto spacecraft. This paper presents a few of the areas such as IVHM, where new wireless sensing technology is needed on both existing vehicles as well as future spacecraft. From ground tests to inflatable structures to the International Space Station, many applications could receive benefits from small, low power, wireless sensors. This paper also highlights some of the challenges that need to overcome when implementing wireless sensor networks for aerospace vehicles.

Routing Protocols in Wireless Sensor Networks

PubMed Central

Villalba, Luis Javier García; Orozco, Ana Lucila Sandoval; Cabrera, Alicia Triviño; Abbas, Cláudia Jacy Barenco

2009-01-01

The applications of wireless sensor networks comprise a wide variety of scenarios. In most of them, the network is composed of a significant number of nodes deployed in an extensive area in which not all nodes are directly connected. Then, the data exchange is supported by multihop communications. Routing protocols are in charge of discovering and maintaining the routes in the network. However, the appropriateness of a particular routing protocol mainly depends on the capabilities of the nodes and on the application requirements. This paper presents a review of the main routing protocols proposed for wireless sensor networks. Additionally, the paper includes the efforts carried out by Spanish universities on developing optimization techniques in the area of routing protocols for wireless sensor networks. PMID:22291515

Report of the sensor readout electronics panel

NASA Technical Reports Server (NTRS)

Fossum, Eric R.; Carson, J.; Kleinhans, W.; Kosonocky, W.; Kozlowski, L.; Pecsalski, A.; Silver, A.; Spieler, H.; Woolaway, J.

1991-01-01

The findings of the Sensor Readout Electronics Panel are summarized in regard to technology assessment and recommended development plans. In addition to two specific readout issues, cryogenic readouts and sub-electron noise, the panel considered three advanced technology areas that impact the ability to achieve large format sensor arrays. These are mega-pixel focal plane packaging issues, focal plane to data processing module interfaces, and event driven readout architectures. Development in each of these five areas was judged to have significant impact in enabling the sensor performance desired for the Astrotech 21 mission set. Other readout issues, such as focal plane signal processing or other high volume data acquisition applications important for Eos-type mapping, were determined not to be relevant for astrophysics science goals.

Routing protocols in wireless sensor networks.

PubMed

Villalba, Luis Javier García; Orozco, Ana Lucila Sandoval; Cabrera, Alicia Triviño; Abbas, Cláudia Jacy Barenco

2009-01-01

The applications of wireless sensor networks comprise a wide variety of scenarios. In most of them, the network is composed of a significant number of nodes deployed in an extensive area in which not all nodes are directly connected. Then, the data exchange is supported by multihop communications. Routing protocols are in charge of discovering and maintaining the routes in the network. However, the appropriateness of a particular routing protocol mainly depends on the capabilities of the nodes and on the application requirements. This paper presents a review of the main routing protocols proposed for wireless sensor networks. Additionally, the paper includes the efforts carried out by Spanish universities on developing optimization techniques in the area of routing protocols for wireless sensor networks.

Small Pitch Transition-Edge Sensors with Broadband High Spectral Resolution for Solar Physics

NASA Technical Reports Server (NTRS)

Smith, S. J.; Adams, J. S.; Eckart, M. E.; Smith, Adams; Bailey, C. N.; Bandler, S. R.; Chevenak, J. A.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.;

Fast Uncooled Low Density FPA of VPD PbSe for Applications in Hyperspectral Imagery

DTIC Science & Technology

2009-10-01

Marañosa (ITM-CIDA). Area de Optronica y Acustica Unidad de Sensores y Micro-Nano Tecnologia Arturo Soria, 289 E-28033 Madrid, Spain ABSTRACT...ADDRESS(ES) Instituto Tecnologico de la Marañosa (ITM-CIDA). Area de Optronica y Acustica Unidad de Sensores y Micro-Nano Tecnologia Arturo Soria, 289

30 CFR 75.371 - Mine ventilation plan; contents.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., accumulations of methane-air mixtures, and other gases, dusts, and fumes in the worked-out area (see § 75.334(f... sensors are installed. (ii) The locations (designated areas) where dust measurements would be made in the... with §§ 75.350(c) and 75.350(d)(5). (mm) The location of any diesel-discriminating sensor, and...

Metal nanostructures for non-enzymatic glucose sensing.

PubMed

Tee, Si Yin; Teng, Choon Peng; Ye, Enyi

2017-01-01

This review covers the recent development of metal nanostructures in electrochemical non-enzymatic glucose sensing. It highlights a variety of nanostructured materials including noble metals, other transition metals, bimetallic systems, and their hybrid with carbon-based nanomaterials. Particularly, attention is devoted to numerous approaches that have been implemented for improving the sensors performance by tailoring size, shape, composition, effective surface area, adsorption capability and electron-transfer properties. The correlation of the metal nanostructures to the glucose sensing performance is addressed with respect to the linear concentration range, sensitivity and detection limit. In overall, this review provides important clues from the recent scientific achievements of glucose sensor nanomaterials which will be essentially useful in designing better and more effective electrocatalysts for future electrochemical sensing industry. Copyright © 2016 Elsevier B.V. All rights reserved.

Linear polarizer local characterizations by polarimetric imaging for applications to polarimetric sensors for torque measurement for hybrid cars

NASA Astrophysics Data System (ADS)

Georges, F.; Remouche, M.; Meyrueis, P.

2011-06-01

Usually manufacturer's specifications do not deal with the ability of linear sheet polarizers to have a constant transmittance function over their geometric area. These parameters are fundamental for developing low cost polarimetric sensors(for instance rotation, torque, displacement) specifically for hybrid car (thermic + electricity power). It is then necessary to specially characterize commercial polarizers sheets to find if they are adapted to this kind of applications. In this paper, we present measuring methods and bench developed for this purpose, and some preliminary characterization results. We state conclusions for effective applications to hybrid car gearbox control and monitoring.

Designing and Testing Energy Harvesters Suitable for Renewable Power Sources

NASA Astrophysics Data System (ADS)

Synkiewicz, B.; Guzdek, P.; Piekarski, J.; Zaraska, K.

2016-01-01

Energy harvesters convert waste power (heat, light and vibration) directly to electric power . Fast progress in their technology, design and areas of application (e.g. “Internet of Things”) has been observed recently. Their effectiveness is steadily growing which makes their application to powering sensor networks with wireless data transfer reasonable. The main advantage is the independence from wired power sources, which is especially important for monitoring state of environmental parameters. In this paper we describe the design and realization of a gas sensor monitoring CO level (powered by TEG) and two, designed an constructed in ITE, autonomous power supply modules powered by modern photovoltaic cells.

Spectroscopic study of Pbs nano-structured layer prepared by Pld utilized as a Hall-effect magnetic sensor

NASA Astrophysics Data System (ADS)

Atwa, D. M.; Aboulfotoh, N.; El-magd, A. Abo; Badr, Y.

2013-10-01

Lead sulfide (PbS) nano-structured films have been grown on quartz substrates using PLD technique. The deposited films were characterized by several structural techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Selected-area electron diffraction patterns (SAED). The results prove the formation of cubic phase of PbS nanocrystals. Elemental analysis of the deposited films compared to the bulk target was obtained via laser induced fluorescence of the produced plasma particles and the energy dispersive X-ray "EDX" technique. The Hall coefficient measurements indicate an efficient performance of the deposited films as a magnetic sensor.

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

PubMed Central

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

2017-01-01

Recently, there has been increasing interest in studying the task coordination of aerial and ground robots. When a robot begins navigation in an unknown area, it has no information about the surrounding environment. Accordingly, for robots to perform tasks based on location information, they need a simultaneous localization and mapping (SLAM) process that uses sensor information to draw a map of the environment, while simultaneously estimating the current location of the robot on the map. This paper aims to present a localization method based in cooperation between aerial and ground robots in an indoor environment. The proposed method allows a ground robot to reach accurate destination by using a 2.5D elevation map built by a low-cost RGB-D (Red Green and Blue-Depth) sensor and 2D Laser sensor attached onto an aerial robot. A 2.5D elevation map is formed by projecting height information of an obstacle using depth information obtained by the RGB-D sensor onto a grid map, which is generated by using the 2D Laser sensor and scan matching. Experimental results demonstrate the effectiveness of the proposed method for its accuracy in location recognition and computing speed. PMID:29186843

Diffraction-based optical sensor detection system for capture-restricted environments

NASA Astrophysics Data System (ADS)

Khandekar, Rahul M.; Nikulin, Vladimir V.

2008-04-01

The use of digital cameras and camcorders in prohibited areas presents a growing problem. Piracy in the movie theaters results in huge revenue loss to the motion picture industry every year, but still image and video capture may present even a bigger threat if performed in high-security locations. While several attempts are being made to address this issue, an effective solution is yet to be found. We propose to approach this problem using a very commonly observed optical phenomenon. Cameras and camcorders use CCD and CMOS sensors, which include a number of photosensitive elements/pixels arranged in a certain fashion. Those are photosites in CCD sensors and semiconductor elements in CMOS sensors. They are known to reflect a small fraction of incident light, but could also act as a diffraction grating, resulting in the optical response that could be utilized to identify the presence of such a sensor. A laser-based detection system is proposed that accounts for the elements in the optical train of the camera, as well as the eye-safety of the people who could be exposed to optical beam radiation. This paper presents preliminary experimental data, as well as the proof-of-concept simulation results.

An Effective Terrain Aided Navigation for Low-Cost Autonomous Underwater Vehicles.

PubMed

Zhou, Ling; Cheng, Xianghong; Zhu, Yixian; Dai, Chenxi; Fu, Jinbo

2017-03-25

Terrain-aided navigation is a potentially powerful solution for obtaining submerged position fixes for autonomous underwater vehicles. The application of terrain-aided navigation with high-accuracy inertial navigation systems has demonstrated meter-level navigation accuracy in sea trials. However, available sensors may be limited depending on the type of the mission. Such limitations, especially for low-grade navigation sensors, not only degrade the accuracy of traditional navigation systems, but further impact the ability to successfully employ terrain-aided navigation. To address this problem, a tightly-coupled navigation is presented to successfully estimate the critical sensor errors by incorporating raw sensor data directly into an augmented navigation system. Furthermore, three-dimensional distance errors are calculated, providing measurement updates through the particle filter for absolute and bounded position error. The development of the terrain aided navigation system is elaborated for a vehicle equipped with a non-inertial-grade strapdown inertial navigation system, a 4-beam Doppler Velocity Log range sensor and a sonar altimeter. Using experimental data for navigation performance evaluation in areas with different terrain characteristics, the experiment results further show that the proposed method can be successfully applied to the low-cost AUVs and significantly improves navigation performance.

An Effective Terrain Aided Navigation for Low-Cost Autonomous Underwater Vehicles

PubMed Central

Zhou, Ling; Cheng, Xianghong; Zhu, Yixian; Dai, Chenxi; Fu, Jinbo

2017-01-01

Terrain-aided navigation is a potentially powerful solution for obtaining submerged position fixes for autonomous underwater vehicles. The application of terrain-aided navigation with high-accuracy inertial navigation systems has demonstrated meter-level navigation accuracy in sea trials. However, available sensors may be limited depending on the type of the mission. Such limitations, especially for low-grade navigation sensors, not only degrade the accuracy of traditional navigation systems, but further impact the ability to successfully employ terrain-aided navigation. To address this problem, a tightly-coupled navigation is presented to successfully estimate the critical sensor errors by incorporating raw sensor data directly into an augmented navigation system. Furthermore, three-dimensional distance errors are calculated, providing measurement updates through the particle filter for absolute and bounded position error. The development of the terrain aided navigation system is elaborated for a vehicle equipped with a non-inertial-grade strapdown inertial navigation system, a 4-beam Doppler Velocity Log range sensor and a sonar altimeter. Using experimental data for navigation performance evaluation in areas with different terrain characteristics, the experiment results further show that the proposed method can be successfully applied to the low-cost AUVs and significantly improves navigation performance. PMID:28346346

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

PubMed

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

2017-11-25

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

Engineering works and the tidal Chesapeake

NASA Technical Reports Server (NTRS)

Hargis, W. J., Jr.

1972-01-01

The tidal tributaries of the ocean and coastal areas of the mid-Atlantic region and the ecological significance of engineering projects are discussed. The effects of engineering works on maritime environments and resources, with the Chesapeake Bay as the area of prime interest are examined. Significant engineering projects, both actual and proposed, are described. The conflict of navigational demands and maintenance of an estuarine environment for commercial and sport fishing and recreation is described. Specific applications of remote sensors for analyzing ecological conditions of the bay are included.

Fiber Bragg Grating Sensors for the Oil Industry.

PubMed

Qiao, Xueguang; Shao, Zhihua; Bao, Weijia; Rong, Qiangzhou

2017-02-23

With the oil and gas industry growing rapidly, increasing the yield and profit require advances in technology for cost-effective production in key areas of reservoir exploration and in oil-well production-management. In this paper we review our group's research into fiber Bragg gratings (FBGs) and their applications in the oil industry, especially in the well-logging field. FBG sensors used for seismic exploration in the oil and gas industry need to be capable of measuring multiple physical parameters such as temperature, pressure, and acoustic waves in a hostile environment. This application requires that the FBG sensors display high sensitivity over the broad vibration frequency range of 5 Hz to 2.5 kHz, which contains the important geological information. We report the incorporation of mechanical transducers in the FBG sensors to enable enhance the sensors' amplitude and frequency response. Whenever the FBG sensors are working within a well, they must withstand high temperatures and high pressures, up to 175 °C and 40 Mpa or more. We use femtosecond laser side-illumination to ensure that the FBGs themselves have the high temperature resistance up to 1100 °C. Using FBG sensors combined with suitable metal transducers, we have experimentally realized high- temperature and pressure measurements up to 400 °C and 100 Mpa. We introduce a novel technology of ultrasonic imaging of seismic physical models using FBG sensors, which is superior to conventional seismic exploration methods. Compared with piezoelectric transducers, FBG ultrasonic sensors demonstrate superior sensitivity, more compact structure, improved spatial resolution, high stability and immunity to electromagnetic interference (EMI). In the last section, we present a case study of a well-logging field to demonstrate the utility of FBG sensors in the oil and gas industry.

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

NASA Astrophysics Data System (ADS)

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

2017-05-01

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

Bias estimation for moving optical sensor measurements with targets of opportunity

NASA Astrophysics Data System (ADS)

Belfadel, Djedjiga; Osborne, Richard W.; Bar-Shalom, Yaakov

2014-06-01

Integration of space based sensors into a Ballistic Missile Defense System (BMDS) allows for detection and tracking of threats over a larger area than ground based sensors [1]. This paper examines the effect of sensor bias error on the tracking quality of a Space Tracking and Surveillance System (STSS) for the highly non-linear problem of tracking a ballistic missile. The STSS constellation consists of two or more satellites (on known trajectories) for tracking ballistic targets. Each satellite is equipped with an IR sensor that provides azimuth and elevation to the target. The tracking problem is made more difficult due to a constant or slowly varying bias error present in each sensor's line of sight measurements. It is important to correct for these bias errors so that the multiple sensor measurements and/or tracks can be referenced as accurately as possible to a common tracking coordinate system. The measurements provided by these sensors are assumed time-coincident (synchronous) and perfectly associated. The line of sight (LOS) measurements from the sensors can be fused into measurements which are the Cartesian target position, i.e., linear in the target state. We evaluate the Cramér-Rao Lower Bound (CRLB) on the covariance of the bias estimates, which serves as a quantification of the available information about the biases. Statistical tests on the results of simulations show that this method is statistically efficient, even for small sample sizes (as few as two sensors and six points on the (unknown) trajectory of a single target of opportunity). We also show that the RMS position error is significantly improved with bias estimation compared with the target position estimation using the original biased measurements.

Mountainous Ecosystem Sensor Array (MESA): a mesh sensor network for climate change research in remote mountainous environments

NASA Astrophysics Data System (ADS)

Robinson, P. W.; Neal, D.; Frome, D.; Kavanagh, K.; Davis, A.; Gessler, P. E.; Hess, H.; Holden, Z. A.; Link, T. E.; Newingham, B. A.; Smith, A. M.

2013-12-01

Developing sensor networks robust enough to perform unattended in the world's remote regions is critical since these regions serve as important benchmarks that lack anthropogenic influence. Paradoxically, the factors that make these remote, natural sites challenging for sensor networking are often what make them indispensable for climate change research. The MESA (Mountainous Ecosystem Sensor Array) project has faced these challenges and developed a wireless mesh sensor network across a 660 m topoclimatic gradient in a wilderness area in central Idaho. This sensor array uses advances in sensing, networking, and power supply technologies to provide near real-time synchronized data covering a suite of biophysical parameters used in ecosystem process models. The 76 sensors in the network monitor atmospheric carbon dioxide concentration, humidity, air and soil temperature, soil water content, precipitation, incoming and outgoing shortwave and longwave radiation, snow depth, wind speed and direction, and leaf wetness at synchronized time intervals ranging from two minutes to two hours and spatial scales from a few meters to two kilometers. We present our novel methods of placing sensors and network nodes above, below, and throughout the forest canopy without using meteorological towers. In addition, we explain our decision to use different forms of power (wind and solar) and the equipment we use to control and integrate power harvesting. Further, we describe our use of the network to sense and quantify its own power use. Using examples of environmental data from the project, we discuss how these data may be used to increase our understanding of the effects of climate change on ecosystem processes in mountainous environments. MESA sensor locations across a 700 m topoclimatic gradient at the University of Idaho Taylor Wilderness Research Station.

Soldier Protection Benchmark Evaluation (SPBE) Physiological Data Collection and Analysis, Fort Greely, Alaska, 17 September-5 October 2012

DTIC Science & Technology

2013-08-19

different protective gear configurations. Data from the sensors supplied by MIT LL were analyzed to assess the effects of the various configurations on the...dotted lines. 24 21 Example of moving an accelerometer around various axes to demonstrate the effect of gravity on accelerometer measurements. 25...specifically in the areas of modularity, scalability, mission-tailoring, and equipment weight. Typically this equipment has been measured for effects

Sensors, Volume 4, Thermal Sensors

NASA Astrophysics Data System (ADS)

Scholz, Jorg; Ricolfi, Teresio

1996-12-01

'Sensors' is the first self-contained series to deal with the whole area of sensors. It describes general aspects, technical and physical fundamentals, construction, function, applications and developments of the various types of sensors. This volume describes the construction and applicational aspects of thermal sensors while presenting a rigorous treatment of the underlying physical principles. It provides a unique overview of the various categories of sensors as well as of specific groups, e.g. temperature sensors (resistance thermometers, thermocouples, and radiation thermometers), noise and acoustic thermometers, heat-flow and mass-flow sensors. Specific facettes of applications are presented by specialists from different fields including process control, automotive technology and cryogenics. This volume is an indispensable reference work and text book for both specialists and newcomers, researchers and developers.

Expected accuracy of proximal and distal temperature estimated by wireless sensors, in relation to their number and position on the skin.

PubMed

Longato, Enrico; Garrido, Maria; Saccardo, Desy; Montesinos Guevara, Camila; Mani, Ali R; Bolognesi, Massimo; Amodio, Piero; Facchinetti, Andrea; Sparacino, Giovanni; Montagnese, Sara

2017-01-01

A popular method to estimate proximal/distal temperature (TPROX and TDIST) consists in calculating a weighted average of nine wireless sensors placed on pre-defined skin locations. Specifically, TPROX is derived from five sensors placed on the infra-clavicular and mid-thigh area (left and right) and abdomen, and TDIST from four sensors located on the hands and feet. In clinical practice, the loss/removal of one or more sensors is a common occurrence, but limited information is available on how this affects the accuracy of temperature estimates. The aim of this study was to determine the accuracy of temperature estimates in relation to number/position of sensors removed. Thirteen healthy subjects wore all nine sensors for 24 hours and reference TPROX and TDIST time-courses were calculated using all sensors. Then, all possible combinations of reduced subsets of sensors were simulated and suitable weights for each sensor calculated. The accuracy of TPROX and TDIST estimates resulting from the reduced subsets of sensors, compared to reference values, was assessed by the mean squared error, the mean absolute error (MAE), the cross-validation error and the 25th and 75th percentiles of the reconstruction error. Tables of the accuracy and sensor weights for all possible combinations of sensors are provided. For instance, in relation to TPROX, a subset of three sensors placed in any combination of three non-homologous areas (abdominal, right or left infra-clavicular, right or left mid-thigh) produced an error of 0.13°C MAE, while the loss/removal of the abdominal sensor resulted in an error of 0.25°C MAE, with the greater impact on the quality of the reconstruction. This information may help researchers/clinicians: i) evaluate the expected goodness of their TPROX and TDIST estimates based on the number of available sensors; ii) select the most appropriate subset of sensors, depending on goals and operational constraints.

Expected accuracy of proximal and distal temperature estimated by wireless sensors, in relation to their number and position on the skin

PubMed Central

Longato, Enrico; Garrido, Maria; Saccardo, Desy; Montesinos Guevara, Camila; Mani, Ali R.; Bolognesi, Massimo; Amodio, Piero; Facchinetti, Andrea; Sparacino, Giovanni

2017-01-01

A popular method to estimate proximal/distal temperature (TPROX and TDIST) consists in calculating a weighted average of nine wireless sensors placed on pre-defined skin locations. Specifically, TPROX is derived from five sensors placed on the infra-clavicular and mid-thigh area (left and right) and abdomen, and TDIST from four sensors located on the hands and feet. In clinical practice, the loss/removal of one or more sensors is a common occurrence, but limited information is available on how this affects the accuracy of temperature estimates. The aim of this study was to determine the accuracy of temperature estimates in relation to number/position of sensors removed. Thirteen healthy subjects wore all nine sensors for 24 hours and reference TPROX and TDIST time-courses were calculated using all sensors. Then, all possible combinations of reduced subsets of sensors were simulated and suitable weights for each sensor calculated. The accuracy of TPROX and TDIST estimates resulting from the reduced subsets of sensors, compared to reference values, was assessed by the mean squared error, the mean absolute error (MAE), the cross-validation error and the 25th and 75th percentiles of the reconstruction error. Tables of the accuracy and sensor weights for all possible combinations of sensors are provided. For instance, in relation to TPROX, a subset of three sensors placed in any combination of three non-homologous areas (abdominal, right or left infra-clavicular, right or left mid-thigh) produced an error of 0.13°C MAE, while the loss/removal of the abdominal sensor resulted in an error of 0.25°C MAE, with the greater impact on the quality of the reconstruction. This information may help researchers/clinicians: i) evaluate the expected goodness of their TPROX and TDIST estimates based on the number of available sensors; ii) select the most appropriate subset of sensors, depending on goals and operational constraints. PMID:28666029

Cooperation among wirelessly connected static and mobile sensor nodes for surveillance applications.

PubMed

de Freitas, Edison Pignaton; Heimfarth, Tales; Vinel, Alexey; Wagner, Flávio Rech; Pereira, Carlos Eduardo; Larsson, Tony

2013-09-25

This paper presents a bio-inspired networking strategy to support the cooperation between static sensors on the ground and mobile sensors in the air to perform surveillance missions in large areas. The goal of the proposal is to provide low overhead in the communication among sensor nodes, while allocating the mobile sensors to perform sensing activities requested by the static ones. Simulations have shown that the strategy is efficient in maintaining low overhead and achieving the desired coordination.

Naval sensor data database (NSDD)

NASA Astrophysics Data System (ADS)

Robertson, Candace J.; Tubridy, Lisa H.

1999-08-01

The Naval Sensor Data database (NSDD) is a multi-year effort to archive, catalogue, and disseminate data from all types of sensors to the mine warfare, signal and image processing, and sensor development communities. The purpose is to improve and accelerate research and technology. Providing performers with the data required to develop and validate improvements in hardware, simulation, and processing will foster advances in sensor and system performance. The NSDD will provide a centralized source of sensor data in its associated ground truth, which will support an improved understanding will be benefited in the areas of signal processing, computer-aided detection and classification, data compression, data fusion, and geo-referencing, as well as sensor and sensor system design.

Applying Sensor Networks to Evaluate Air Pollutant Emissions from Fugitive and Area Sources

EPA Science Inventory

This is a presentation to be given at Duke University's Wireless Intelligent Sensor Network workshop on June 5, 2013. The presentation discusses the evaluation of a low cost carbon monoxide sensor network applied at a recent forest fire study and also evaluated against a referen...

Visibility of children behind 2010-2013 model year passenger vehicles using glances, mirrors, and backup cameras and parking sensors.

PubMed

Kidd, David G; Brethwaite, Andrew

2014-05-01

This study identified the areas behind vehicles where younger and older children are not visible and measured the extent to which vehicle technologies improve visibility. Rear visibility of targets simulating the heights of a 12-15-month-old, a 30-36-month-old, and a 60-72-month-old child was assessed in 21 2010-2013 model year passenger vehicles with a backup camera or a backup camera plus parking sensor system. The average blind zone for a 12-15-month-old was twice as large as it was for a 60-72-month-old. Large SUVs had the worst rear visibility and small cars had the best. Increases in rear visibility provided by backup cameras were larger than the non-visible areas detected by parking sensors, but parking sensors detected objects in areas near the rear of the vehicle that were not visible in the camera or other fields of view. Overall, backup cameras and backup cameras plus parking sensors reduced the blind zone by around 90 percent on average and have the potential to prevent backover crashes if drivers use the technology appropriately. Copyright © 2014 Elsevier Ltd. All rights reserved.

Status of HVCMOS developments for ATLAS

NASA Astrophysics Data System (ADS)

Perić, I.; Blanco, R.; Casanova Mohr, R.; Ehrler, F.; Guezzi Messaoud, F.; Krämer, C.; Leys, R.; Prathapan, M.; Schimassek, R.; Schöning, A.; Vilella Figueras, E.; Weber, A.; Zhang, H.

2017-02-01

This paper describes the status of the developments made by ATLAS HVCMOS and HVMAPS collaborations. We have proposed two HVCMOS sensor concepts for ATLAS pixels—the capacitive coupled pixel detector (CCPD) and the monolithic detector. The sensors have been implemented in three semiconductor processes AMS H18, AMS H35 and LFoundry LFA15. Efficiency of 99.7% after neutron irradiation to 1015 neq/cm2W has been measured with the small area CCPD prototype in AMS H18 technology. About 84% of the particles are detected with a time resolution better than 25 ns. The sensor was implemented on a low resistivity substrate. The large area demonstrator sensor in AMS H35 process has been designed, produced and successfully tested. The sensor has been produced on different high resistivity substrates ranging from 80 Ωcm to more than 1 kΩ. Monolithic- and hybrid readout are both possible. In August 2016, six different monolithic pixel matrices for ATLAS with a total area of 1 cm2 have been submitted in LFoundry LFA15 process. The matrices implement column drain and triggered readout as well as waveform sampling capability on pixel level. Design details will be presented.

Enhanced technologies for unattended ground sensor systems

NASA Astrophysics Data System (ADS)

Hartup, David C.

2010-04-01

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

Region-Based Collision Avoidance Beaconless Geographic Routing Protocol in Wireless Sensor Networks.

PubMed

Lee, JeongCheol; Park, HoSung; Kang, SeokYoon; Kim, Ki-Il

2015-06-05

Due to the lack of dependency on beacon messages for location exchange, the beaconless geographic routing protocol has attracted considerable attention from the research community. However, existing beaconless geographic routing protocols are likely to generate duplicated data packets when multiple winners in the greedy area are selected. Furthermore, these protocols are designed for a uniform sensor field, so they cannot be directly applied to practical irregular sensor fields with partial voids. To prevent the failure of finding a forwarding node and to remove unnecessary duplication, in this paper, we propose a region-based collision avoidance beaconless geographic routing protocol to increase forwarding opportunities for randomly-deployed sensor networks. By employing different contention priorities into the mutually-communicable nodes and the rest of the nodes in the greedy area, every neighbor node in the greedy area can be used for data forwarding without any packet duplication. Moreover, simulation results are given to demonstrate the increased packet delivery ratio and shorten end-to-end delay, rather than well-referred comparative protocols.

Region-Based Collision Avoidance Beaconless Geographic Routing Protocol in Wireless Sensor Networks

PubMed Central

Lee, JeongCheol; Park, HoSung; Kang, SeokYoon; Kim, Ki-Il

2015-01-01

Due to the lack of dependency on beacon messages for location exchange, the beaconless geographic routing protocol has attracted considerable attention from the research community. However, existing beaconless geographic routing protocols are likely to generate duplicated data packets when multiple winners in the greedy area are selected. Furthermore, these protocols are designed for a uniform sensor field, so they cannot be directly applied to practical irregular sensor fields with partial voids. To prevent the failure of finding a forwarding node and to remove unnecessary duplication, in this paper, we propose a region-based collision avoidance beaconless geographic routing protocol to increase forwarding opportunities for randomly-deployed sensor networks. By employing different contention priorities into the mutually-communicable nodes and the rest of the nodes in the greedy area, every neighbor node in the greedy area can be used for data forwarding without any packet duplication. Moreover, simulation results are given to demonstrate the increased packet delivery ratio and shorten end-to-end delay, rather than well-referred comparative protocols. PMID:26057037

A Capacitance-To-Digital Converter for MEMS Sensors for Smart Applications.

PubMed

Pérez Sanjurjo, Javier; Prefasi, Enrique; Buffa, Cesare; Gaggl, Richard

2017-06-07

The use of MEMS sensors has been increasing in recent years. To cover all the applications, many different readout circuits are needed. To reduce the cost and time to market, a generic capacitance-to-digital converter (CDC) seems to be the logical next step. This work presents a configurable CDC designed for capacitive MEMS sensors. The sensor is built with a bridge of MEMS, where some of them function with pressure. Then, the capacitive to digital conversion is realized using two steps. First, a switched-capacitor (SC) preamplifier is used to make the capacitive to voltage (C-V) conversion. Second, a self-oscillated noise-shaping integrating dual-slope (DS) converter is used to digitize this magnitude. The proposed converter uses time instead of amplitude resolution to generate a multibit digital output stream. In addition it performs noise shaping of the quantization error to reduce measurement time. This article shows the effectiveness of this method by measurements performed on a prototype, designed and fabricated using standard 0.13 µm CMOS technology. Experimental measurements show that the CDC achieves a resolution of 17 bits, with an effective area of 0.317 mm², which means a pressure resolution of 1 Pa, while consuming 146 µA from a 1.5 V power supply.

A Capacitance-To-Digital Converter for MEMS Sensors for Smart Applications

PubMed Central

Pérez Sanjurjo, Javier; Prefasi, Enrique; Buffa, Cesare; Gaggl, Richard

2017-01-01

The use of MEMS sensors has been increasing in recent years. To cover all the applications, many different readout circuits are needed. To reduce the cost and time to market, a generic capacitance-to-digital converter (CDC) seems to be the logical next step. This work presents a configurable CDC designed for capacitive MEMS sensors. The sensor is built with a bridge of MEMS, where some of them function with pressure. Then, the capacitive to digital conversion is realized using two steps. First, a switched-capacitor (SC) preamplifier is used to make the capacitive to voltage (C-V) conversion. Second, a self-oscillated noise-shaping integrating dual-slope (DS) converter is used to digitize this magnitude. The proposed converter uses time instead of amplitude resolution to generate a multibit digital output stream. In addition it performs noise shaping of the quantization error to reduce measurement time. This article shows the effectiveness of this method by measurements performed on a prototype, designed and fabricated using standard 0.13 µm CMOS technology. Experimental measurements show that the CDC achieves a resolution of 17 bits, with an effective area of 0.317 mm2, which means a pressure resolution of 1 Pa, while consuming 146 µA from a 1.5 V power supply. PMID:28590425

Nanomaterials for Sensor Applications

DOE PAGES

Márquez, Francisco; Morant, Carmen

2015-01-15

A large part of the advances in nanotechnology have been directed towards the development of highspeed electronics, more efficient catalysts, and sensors. This latter group of applications has great relevance and unprecedented development potential for the coming years. Some of the main objectives for the development of sensors have focused on making more sensitive, effective and specific sensing devices. The improvement of these systems and the increase of specificity are clearly associated with a decrease in size of the components, which can lead to obtaining more rapid action, almost in real time. Nanomaterials currently used in sensor development include amore » long list of nanostructured systems, as for example: Metal nanotubes, nanowires, nanofibers, nanocomposites, nanorods, nanoparticles, nanostructured polymers, and different allotropes of carbon as carbon nanotubes, graphene or fullerenes, among others [1]. These nanomaterials are characterized by having unique physicochemical properties, including high electrical and thermal conductivity, extremely high surface area/volume ratio, high mechanical strength and even excellent catalytic properties [1] [2]. These materials, may exhibit relevant physicochemical behavior, such as quantization or electronic confinement effects, which can be used in the development of all kinds of sensors [2]. So far, sensors have been developed for determination and quantification of gases, radiation, biomolecules, microorganisms, etc. [2] [3]. The sensors developed so far usually use the system lock and key, wherein the selective receptor (lock) is selectively anchored to the analyte of interest (or key). This system has great limitations when analyzing the analyte in the presence of other analytes, which can alter the sensitivity or specificity of the measure, as occurs in sensors used in biomedical applications [3] [4]. One possible solution is based on the development of sensor arrays, consisting of a combination of different and specific sensors, which may enable simultaneous measurements of one or more analytes in a less favorable environment [5] in these cases. These sensors are now a reality, although there is still a long way to go before the levels of precision and accuracy are reached. Future challenges for the development and commercialization of efficient sensors are mainly focused on improving the specificity, reproducibility, and the ability to detect trace levels. We hope that in the coming years nanotechnology and nanomaterials allow reaching previously unimaginable advances in the development of these systems.« less

Source Separation of Heartbeat Sounds for Effective E-Auscultation

NASA Astrophysics Data System (ADS)

Geethu, R. S.; Krishnakumar, M.; Pramod, K. V.; George, Sudhish N.

2016-03-01

This paper proposes a cost effective solution for improving the effectiveness of e-auscultation. Auscultation is the most difficult skill for a doctor, since it can be acquired only through experience. The heart sound mixtures are captured by placing the four numbers of sensors at appropriate auscultation area in the body. These sound mixtures are separated to its relevant components by a statistical method independent component analysis. The separated heartbeat sounds can be further processed or can be stored for future reference. This idea can be used for making a low cost, easy to use portable instrument which will be beneficial to people living in remote areas and are unable to take the advantage of advanced diagnosis methods.

Human Subcutaneous Tissue Response to Glucose Sensors: Macrophages Accumulation Impact on Sensor Accuracy.

PubMed

Rigla, Mercedes; Pons, Belén; Rebasa, Pere; Luna, Alexis; Pozo, Francisco Javier; Caixàs, Assumpta; Villaplana, Maria; Subías, David; Bella, Maria Rosa; Combalia, Neus

2018-04-01

Subcutaneous (s.c.) glucose sensors have become a key component in type 1 diabetes management. However, their usability is limited by the impact of foreign body response (FBR) on their duration, reliability, and accuracy. Our study gives the first description of human acute and subacute s.c. response to glucose sensors, showing the changes observed in the sensor surface, the inflammatory cells involved in the FBR and their relationship with sensor performance. Twelve obese patients (seven type 2 diabetes) underwent two abdominal biopsies comprising the surrounding area where they had worn two glucose sensors: the first one inserted 7 days before and the second one 24 h before biopsy procedure. Samples were processed and studied to describe tissue changes by two independent pathologists (blind regarding sensor duration). Macrophages quantification was studied by immunohistochemistry methods in the area surrounding the sensor (CD68, CD163). Sensor surface changes were studied by scanning electron microscopy. Seven-day continuous glucose monitoring records were considered inaccurate when mean absolute relative difference was higher than 10%. Pathologists were able to correctly classify all the biopsies regarding sensor duration. Acute response (24 h) was characterized by the presence of neutrophils while macrophages were the main cell involved in subacute inflammation. The number of macrophages around the insertion hole was higher for less accurate sensors compared with those performing more accurately (32.6 ± 14 vs. 10.6 ± 1 cells/0.01 mm 2 ; P < 0.05). The accumulation of macrophages at the sensor-tissue interface is related with decrease in accuracy of the glucose measure.

Effects of electrode surface structure on the mechanoelectrical transduction of IPMC sensors

NASA Astrophysics Data System (ADS)

Palmre, Viljar; Pugal, David; Kim, Kwang

2014-03-01

This study investigates the effects of electrode surface structure on the mechanoelectrical transduction of IPMC sensors. A physics-based mechanoelectrical transduction model was developed that takes into account the electrode surface profile (shape) by describing the polymer-electrode interface as a Koch fractal structure. Based on the model, the electrode surface effects were experimentally investigated in case of IPMCs with Pd-Pt electrodes. IPMCs with different electrode surface structures were fabricated through electroless plating process by appropriately controlling the synthesis parameters and conditions. The changes in the electrode surface morphology and the corresponding effects on the IPMC mechanoelectrical transduction were examined. Our experimental results indicate that increasing the dispersion of Pd particles near the membrane surface, and thus the polymer-electrode interfacial area, leads to a higher peak mechanoelectrically induced voltage of IPMC. However, the overall effect of the electrode surface structure is relatively low compared to the electromechanical transduction, which is in good agreement with theoretical prediction.

Sun-view angle effects on reflectance factors of corn canopies

NASA Technical Reports Server (NTRS)

Ranson, K. J.; Daughtry, C. S. T.; Biehl, L. L.; Bauer, M. E.

1985-01-01

The effects of sun and view angles on reflectance factors of corn (Zea mays L.) canopies ranging from the six leaf stage to harvest maturity were studied on the Purdue University Agronomy Farm by a multiband radiometer. The two methods of acquiring spectral data, the truck system and the tower systrem, are described. The analysis of the spectral data is presented in three parts: solar angle effects on reflectance factors viewed at nadir; solar angle effects on reflectance factors viewed at a fixed sun angle; and both sun and view angles effect on reflectance factors. The analysis revealed that for nadir-viewed reflectance factors there is a strong solar angle dependence in all spectral bands for canopies with low leaf area index. Reflectance factors observed from the sun angle at different view azimuth angles showed that the position of the sensor relative to the sun is important in determining angular reflectance characteristics. For both sun and view angles, reflectance factors are maximized when the sensor view direction is towards the sun.

Towards Efficient Wireless Body Area Network Using Two-Way Relay Cooperation.

PubMed

Waheed, Maham; Ahmad, Rizwan; Ahmed, Waqas; Drieberg, Micheal; Alam, Muhammad Mahtab

2018-02-13

The fabrication of lightweight, ultra-thin, low power and intelligent body-borne sensors leads to novel advances in wireless body area networks (WBANs). Depending on the placement of the nodes, it is characterized as in/on body WBAN; thus, the channel is largely affected by body posture, clothing, muscle movement, body temperature and climatic conditions. The energy resources are limited and it is not feasible to replace the sensor's battery frequently. In order to keep the sensor in working condition, the channel resources should be reserved. The lifetime of the sensor is very crucial and it highly depends on transmission among sensor nodes and energy consumption. The reliability and energy efficiency in WBAN applications play a vital role. In this paper, the analytical expressions for energy efficiency (EE) and packet error rate (PER) are formulated for two-way relay cooperative communication. The results depict better reliability and efficiency compared to direct and one-way relay communication. The effective performance range of direct vs. cooperative communication is separated by a threshold distance. Based on EE calculations, an optimal packet size is observed that provides maximum efficiency over a certain link length. A smart and energy efficient system is articulated that utilizes all three communication modes, namely direct, one-way relay and two-way relay, as the direct link performs better for a certain range, but the cooperative communication gives better results for increased distance in terms of EE. The efficacy of the proposed hybrid scheme is also demonstrated over a practical quasi-static channel. Furthermore, link length extension and diversity is achieved by joint network-channel (JNC) coding the cooperative link.

Full-field acoustomammography using an acousto-optic sensor.

PubMed

Sandhu, J S; Schmidt, R A; La Rivière, P J

2009-06-01

In this Letter the authors introduce a wide-field transmission ultrasound approach to breast imaging based on the use of a large area acousto-optic (AO) sensor. Accompanied by a suitable acoustic source, such a detector could be mounted on a traditional mammography system and provide a mammographylike ultrasound projection image of the compressed breast in registration with the x-ray mammogram. The authors call the approach acoustography. The hope is that this additional information could improve the sensitivity and specificity of screening mammography. The AO sensor converts ultrasound directly into a visual image by virtue of the acousto-optic effect of the liquid crystal layer contained in the AO sensor. The image is captured with a digital video camera for processing, analysis, and storage. In this Letter, the authors perform a geometrical resolution analysis and also present images of a multimodality breast phantom imaged with both mammography and acoustography to demonstrate the feasibility of the approach. The geometric resolution analysis suggests that the technique could readily detect tumors of diameter of 3 mm using 8.5 MHz ultrasound, with smaller tumors detectable with higher frequency ultrasound, though depth penetration might then become a limiting factor. The preliminary phantom images show high contrast and compare favorably to digital mammograms of the same phantom. The authors have introduced and established, through phantom imaging, the feasibility of a full-field transmission ultrasound detector for breast imaging based on the use of a large area AO sensor. Of course variations in attenuation of connective, glandular, and fatty tissues will lead to images with more cluttered anatomical background than those of the phantom imaged here. Acoustic coupling to the mammographically compressed breast, particularly at the margins, will also have to be addressed.

Full-field acoustomammography using an acousto-optic sensor

PubMed Central

Sandhu, J. S.; Schmidt, R. A.; La Rivière, P. J.

2009-01-01

In this Letter the authors introduce a wide-field transmission ultrasound approach to breast imaging based on the use of a large area acousto-optic (AO) sensor. Accompanied by a suitable acoustic source, such a detector could be mounted on a traditional mammography system and provide a mammographylike ultrasound projection image of the compressed breast in registration with the x-ray mammogram. The authors call the approach acoustography. The hope is that this additional information could improve the sensitivity and specificity of screening mammography. The AO sensor converts ultrasound directly into a visual image by virtue of the acousto-optic effect of the liquid crystal layer contained in the AO sensor. The image is captured with a digital video camera for processing, analysis, and storage. In this Letter, the authors perform a geometrical resolution analysis and also present images of a multimodality breast phantom imaged with both mammography and acoustography to demonstrate the feasibility of the approach. The geometric resolution analysis suggests that the technique could readily detect tumors of diameter of 3 mm using 8.5 MHz ultrasound, with smaller tumors detectable with higher frequency ultrasound, though depth penetration might then become a limiting factor. The preliminary phantom images show high contrast and compare favorably to digital mammograms of the same phantom. The authors have introduced and established, through phantom imaging, the feasibility of a full-field transmission ultrasound detector for breast imaging based on the use of a large area AO sensor. Of course variations in attenuation of connective, glandular, and fatty tissues will lead to images with more cluttered anatomical background than those of the phantom imaged here. Acoustic coupling to the mammographically compressed breast, particularly at the margins, will also have to be addressed. PMID:19610321

A MAPS Based Micro-Vertex Detector for the STAR Experiment

DOE PAGES

Schambach, Joachim; Anderssen, Eric; Contin, Giacomo; ...

2015-06-18

For the 2014 heavy ion run of RHIC a new micro-vertex detector called the Heavy Flavor Tracker (HFT) was installed in the STAR experiment. The HFT consists of three detector subsystems with various silicon technologies arranged in 4 approximately concentric cylinders close to the STAR interaction point designed to improve the STAR detector’s vertex resolution and extend its measurement capabilities in the heavy flavor domain. The two innermost HFT layers are placed at radii of 2.8 cm and 8 cm from the beam line. These layers are constructed with 400 high resolution sensors based on CMOS Monolithic Active Pixel Sensormore » (MAPS) technology arranged in 10-sensor ladders mounted on 10 thin carbon fiber sectors to cover a total silicon area of 0.16 m 2. Each sensor of this PiXeL (“PXL”) sub-detector combines a pixel array of 928 rows and 960 columns with a 20.7 μm pixel pitch together with front-end electronics and zero-suppression circuitry in one silicon die providing a sensitive area of ~3.8 cm 2. This sensor architecture features 185.6 μs readout time and 170 mW/cm 2 power dissipation. This low power dissipation allows the PXL detector to be air-cooled, and with the sensors thinned down to 50 μm results in a global material budget of only 0.4% radiation length per layer. A novel mechanical approach to detector insertion allows us to effectively install and integrate the PXL sub-detector within a 12 hour period during an on-going multi-month data taking period. The detector requirements, architecture and design, as well as the performance after installation, are presented in this paper.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schambach, Joachim; Anderssen, Eric; Contin, Giacomo

For the 2014 heavy ion run of RHIC a new micro-vertex detector called the Heavy Flavor Tracker (HFT) was installed in the STAR experiment. The HFT consists of three detector subsystems with various silicon technologies arranged in 4 approximately concentric cylinders close to the STAR interaction point designed to improve the STAR detector’s vertex resolution and extend its measurement capabilities in the heavy flavor domain. The two innermost HFT layers are placed at radii of 2.8 cm and 8 cm from the beam line. These layers are constructed with 400 high resolution sensors based on CMOS Monolithic Active Pixel Sensormore » (MAPS) technology arranged in 10-sensor ladders mounted on 10 thin carbon fiber sectors to cover a total silicon area of 0.16 m 2. Each sensor of this PiXeL (“PXL”) sub-detector combines a pixel array of 928 rows and 960 columns with a 20.7 μm pixel pitch together with front-end electronics and zero-suppression circuitry in one silicon die providing a sensitive area of ~3.8 cm 2. This sensor architecture features 185.6 μs readout time and 170 mW/cm 2 power dissipation. This low power dissipation allows the PXL detector to be air-cooled, and with the sensors thinned down to 50 μm results in a global material budget of only 0.4% radiation length per layer. A novel mechanical approach to detector insertion allows us to effectively install and integrate the PXL sub-detector within a 12 hour period during an on-going multi-month data taking period. The detector requirements, architecture and design, as well as the performance after installation, are presented in this paper.« less

Data Assimilation and verification based on GEO microwave observations

NASA Astrophysics Data System (ADS)

He, J.

2017-12-01

THE frequency band from 50 to 56 GHz has been used to retrieve atmospheric temperature profiles through radiometric measurements at and near absorption maxima. Sensors working around 50-56 GHz are now only available on low earth orbit (LEO), and are still lacked in the geostationary earth orbit (GEO) application. Compared with LEO sounding, sensors working in GEO orbit can continuously monitor the full earth disk and perform. The Geostationary Interferometric Microwave Sounder (GIMS) is a synthetic aperture microwave sounder working in time-sharing sampling mode with a rotating circular antenna array. Real-time forecasting for short-term meteorological phenomena such as tropical cyclones, which is one of the most important natural disasters that cause severe damage in coastal areas around the world. Furthermore, since information available in microwave band is different from that available in visible/ infrared frequency, microwave sensor in GEO orbit can complement the existing sensors in GEO orbit that work in visible/infrared frequency to determine vertical temperature distribution and thus help investigate inner structure of tropical cyclone. As we know, a lot of improvement of WRFDA has been realized, such as radar data and LEO microwave data. It has the ability of providing initial conditions for the WRF model and assessing observing system. However, one major constraint of WRFDA is the ability of assimilating GEO microwave observations into the assimilation model and verify how the GIMS sensor effect the output data of model, especially for synthetic aperture microwave sounder. So, for my group, we focus on surface pressure and precipitation in hurricane and typhoon areas based on WRF and WRFDA model, and also, combine polar-orbit observations and geostationary microwave simulations to improve the tracking accuracy.

Multiscale Hierarchical Design of a Flexible Piezoresistive Pressure Sensor with High Sensitivity and Wide Linearity Range.

PubMed

Shi, Jidong; Wang, Liu; Dai, Zhaohe; Zhao, Lingyu; Du, Mingde; Li, Hongbian; Fang, Ying

2018-05-30

Flexible piezoresistive pressure sensors have been attracting wide attention for applications in health monitoring and human-machine interfaces because of their simple device structure and easy-readout signals. For practical applications, flexible pressure sensors with both high sensitivity and wide linearity range are highly desirable. Herein, a simple and low-cost method for the fabrication of a flexible piezoresistive pressure sensor with a hierarchical structure over large areas is presented. The piezoresistive pressure sensor consists of arrays of microscale papillae with nanoscale roughness produced by replicating the lotus leaf's surface and spray-coating of graphene ink. Finite element analysis (FEA) shows that the hierarchical structure governs the deformation behavior and pressure distribution at the contact interface, leading to a quick and steady increase in contact area with loads. As a result, the piezoresistive pressure sensor demonstrates a high sensitivity of 1.2 kPa -1 and a wide linearity range from 0 to 25 kPa. The flexible pressure sensor is applied for sensitive monitoring of small vibrations, including wrist pulse and acoustic waves. Moreover, a piezoresistive pressure sensor array is fabricated for mapping the spatial distribution of pressure. These results highlight the potential applications of the flexible piezoresistive pressure sensor for health monitoring and electronic skin. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Outline of Data Aggregation Security in Heterogeneous Wireless Sensor Networks

PubMed Central

Boubiche, Sabrina; Boubiche, Djallel Eddine; Bilami, Azzedine; Toral-Cruz, Homero

2016-01-01

Data aggregation processes aim to reduce the amount of exchanged data in wireless sensor networks and consequently minimize the packet overhead and optimize energy efficiency. Securing the data aggregation process is a real challenge since the aggregation nodes must access the relayed data to apply the aggregation functions. The data aggregation security problem has been widely addressed in classical homogeneous wireless sensor networks, however, most of the proposed security protocols cannot guarantee a high level of security since the sensor node resources are limited. Heterogeneous wireless sensor networks have recently emerged as a new wireless sensor network category which expands the sensor nodes’ resources and capabilities. These new kinds of WSNs have opened new research opportunities where security represents a most attractive area. Indeed, robust and high security level algorithms can be used to secure the data aggregation at the heterogeneous aggregation nodes which is impossible in classical homogeneous WSNs. Contrary to the homogeneous sensor networks, the data aggregation security problem is still not sufficiently covered and the proposed data aggregation security protocols are numberless. To address this recent research area, this paper describes the data aggregation security problem in heterogeneous wireless sensor networks and surveys a few proposed security protocols. A classification and evaluation of the existing protocols is also introduced based on the adopted data aggregation security approach. PMID:27077866

Acoustic Emission of Large PRSEUS Structures (Pultruded Rod Stitched Efficient Unitized Structure)

NASA Technical Reports Server (NTRS)

Horne, Michael R.; Juarez, Peter D.

2016-01-01

In the role of structural health monitoring (SHM), Acoustic Emission (AE) analysis is being investigated as an effective method for tracking damage development in large composite structures under load. Structures made using Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) for damage tolerant, light, and economical airframe construction are being pursued by The Boeing Company and NASA under the Environmentally Responsible Aircraft initiative (ERA). The failure tests of two PRSEUS substructures based on the Boeing Hybrid Wing Body fuselage concept were conducted during third quarter 2011 and second quarter 2015. One fundamental concern of these tests was determining the effectiveness of the stitched integral stiffeners to inhibit damage progression. By design, severe degradation of load carrying capability should not occur prior to Design Ultimate Load (DUL). While minor damage prior to DUL was anticipated, the integral stitching should not fail since this would allow a stiffener-skin delamination to progress rapidly and alter the transfer of load into the stiffeners. In addition, the stiffeners should not fracture because they are fundamental to structural integrity. Getting the best information from each AE sensor is a primary consideration because a sparse network of sensors is implemented. Sensitivity to stiffener-contiguous degradation is supported by sensors near the stiffeners, which increases the coverage per sensor via AE waveguide actions. Some sensors are located near potentially critical areas or "critical zones" as identified by numerical analyses. The approach is compared with the damage progression monitored by other techniques (e.g. ultrasonic C-scan).

Design of a WSN for the Sampling of Environmental Variability in Complex Terrain

PubMed Central

Martín-Tardío, Miguel A.; Felicísimo, Ángel M.

2014-01-01

In-situ environmental parameter measurements using sensor systems connected to a wireless network have become widespread, but the problem of monitoring large and mountainous areas by means of a wireless sensor network (WSN) is not well resolved. The main reasons for this are: (1) the environmental variability distribution is unknown in the field; (2) without this knowledge, a huge number of sensors would be necessary to ensure the complete coverage of the environmental variability and (3) WSN design requirements, for example, effective connectivity (intervisibility), limiting distances and controlled redundancy, are usually solved by trial and error. Using temperature as the target environmental variable, we propose: (1) a method to determine the homogeneous environmental classes to be sampled using the digital elevation model (DEM) and geometric simulations and (2) a procedure to determine an effective WSN design in complex terrain in terms of the number of sensors, redundancy, cost and spatial distribution. The proposed methodology, based on geographic information systems and binary integer programming can be easily adapted to a wide range of applications that need exhaustive and continuous environmental monitoring with high spatial resolution. The results show that the WSN design is perfectly suited to the topography and the technical specifications of the sensors, and provides a complete coverage of the environmental variability in terms of Sun exposure. However these results still need be validated in the field and the proposed procedure must be refined. PMID:25412218

A smart indoor air quality sensor network

NASA Astrophysics Data System (ADS)

Wen, Jin

2006-03-01

The indoor air quality (IAQ) has an important impact on public health. Currently, the indoor air pollution, caused by gas, particle, and bio-aerosol pollutants, is considered as the top five environmental risks to public health and has an estimated cost of $2 billion/year due to medical cost and lost productivity. Furthermore, current buildings are especially vulnerable for chemical and biological warfare (CBW) agent contamination because the central air conditioning and ventilation system serve as a nature carrier to spread the released agent from one location to the whole indoor environment within a short time period. To assure the IAQ and safety for either new or existing buildings, real time comprehensive IAQ and CBW measurements are needed. With the development of new sensing technologies, economic and reliable comprehensive IAQ and CBW sensors become promising. However, few studies exist that examine the design and evaluation issues related to IAQ and CBW sensor network. In this paper, relevant research areas including IAQ and CBW sensor development, demand control ventilation, indoor CBW sensor system design, and sensor system design for other areas such as water system protection, fault detection and diagnosis, are reviewed and summarized. Potential research opportunities for IAQ and CBW sensor system design and evaluation are discussed.

Nanometric Integrated Temperature and Thermal Sensors in CMOS-SOI Technology.

PubMed

Malits, Maria; Nemirovsky, Yael

2017-07-29

This paper reviews and compares the thermal and noise characterization of CMOS (complementary metal-oxide-semiconductor) SOI (Silicon on insulator) transistors and lateral diodes used as temperature and thermal sensors. DC analysis of the measured sensors and the experimental results in a broad (300 K up to 550 K) temperature range are presented. It is shown that both sensors require small chip area, have low power consumption, and exhibit linearity and high sensitivity over the entire temperature range. However, the diode's sensitivity to temperature variations in CMOS-SOI technology is highly dependent on the diode's perimeter; hence, a careful calibration for each fabrication process is needed. In contrast, the short thermal time constant of the electrons in the transistor's channel enables measuring the instantaneous heating of the channel and to determine the local true temperature of the transistor. This allows accurate "on-line" temperature sensing while no additional calibration is needed. In addition, the noise measurements indicate that the diode's small area and perimeter causes a high 1/ f noise in all measured bias currents. This is a severe drawback for the sensor accuracy when using the sensor as a thermal sensor; hence, CMOS-SOI transistors are a better choice for temperature sensing.

An intelligent surveillance platform for large metropolitan areas with dense sensor deployment.

PubMed

Fernández, Jorge; Calavia, Lorena; Baladrón, Carlos; Aguiar, Javier M; Carro, Belén; Sánchez-Esguevillas, Antonio; Alonso-López, Jesus A; Smilansky, Zeev

2013-06-07

This paper presents an intelligent surveillance platform based on the usage of large numbers of inexpensive sensors designed and developed inside the European Eureka Celtic project HuSIMS. With the aim of maximizing the number of deployable units while keeping monetary and resource/bandwidth costs at a minimum, the surveillance platform is based on the usage of inexpensive visual sensors which apply efficient motion detection and tracking algorithms to transform the video signal in a set of motion parameters. In order to automate the analysis of the myriad of data streams generated by the visual sensors, the platform's control center includes an alarm detection engine which comprises three components applying three different Artificial Intelligence strategies in parallel. These strategies are generic, domain-independent approaches which are able to operate in several domains (traffic surveillance, vandalism prevention, perimeter security, etc.). The architecture is completed with a versatile communication network which facilitates data collection from the visual sensors and alarm and video stream distribution towards the emergency teams. The resulting surveillance system is extremely suitable for its deployment in metropolitan areas, smart cities, and large facilities, mainly because cheap visual sensors and autonomous alarm detection facilitate dense sensor network deployments for wide and detailed coverage.

Comparison of SO2 and NO2 observations from OMI and OMPS from 2012 to 2016

NASA Astrophysics Data System (ADS)

Wang, Y.; Wang, J.; Xu, X.; Yang, K.

2017-12-01

Both Sulfur dioxide (SO2) and nitrogen dioxide (NO2) are precursors of PM2.5 which has significant impacts on human health. We compare observations from Ozone Monitoring Instrument (OMI) which has data gap due to row anomaly and Ozone Mapping Profiler Suite (OMPS) that is currently the only operational UV satellite sensor providing contiguous daily global coverage. In this study, we examine changes of SO2 and NO2 in several polluted regions and see both upward trends and downward trends in different areas but trends observed by the two sensors are consistent in general. Some of these upward and downward trends are associated with economic development and implementation of emission control policy. In addition, we analyzed probability distribution function of SO2 and NO2 from the two sensors and how row anomaly effect the intercomparison.

Graphene-multiwall carbon nanotube-gold nanocluster composites modified electrode for the simultaneous determination of ascorbic acid, dopamine, and uric acid.

PubMed

Liu, Xiaofang; Wei, Shaping; Chen, Shihong; Yuan, Dehua; Zhang, Wen

2014-08-01

In this paper, graphene-multiwall carbon nanotube-gold nanocluster (GP-MWCNT-AuNC) composites were synthesized and used as modifier to fabricate a sensor for simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The electrochemical behavior of the sensor was investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The combination of GP, MWCNTs, and AuNCs endowed the electrode with a large surface area, good catalytic activity, and high selectivity and sensitivity. The linear response range for simultaneous detection of AA, DA, and UA at the sensor were 120-1,701, 2-213, and 0.7-88.3 μM, correspondingly, and the detection limits were 40, 0.67, and 0.23 μM (S/N=3), respectively. The proposed method offers a promise for simple, rapid, selective, and cost-effective analysis of small biomolecules.

Wafer-scale epitaxial graphene on SiC for sensing applications

NASA Astrophysics Data System (ADS)

Karlsson, Mikael; Wang, Qin; Zhao, Yichen; Zhao, Wei; Toprak, Muhammet S.; Iakimov, Tihomir; Ali, Amer; Yakimova, Rositza; Syväjärvi, Mikael; Ivanov, Ivan G.

2015-12-01

The epitaxial graphene-on-silicon carbide (SiC-G) has advantages of high quality and large area coverage owing to a natural interface between graphene and SiC substrate with dimension up to 100 mm. It enables cost effective and reliable solutions for bridging the graphene-based sensors/devices from lab to industrial applications and commercialization. In this work, the structural, optical and electrical properties of wafer-scale graphene grown on 2'' 4H semi-insulating (SI) SiC utilizing sublimation process were systemically investigated with focus on evaluation of the graphene's uniformity across the wafer. As proof of concept, two types of glucose sensors based on SiC-G/Nafion/Glucose-oxidase (GOx) and SiC-G/Nafion/Chitosan/GOx were fabricated and their electrochemical properties were characterized by cyclic voltammetry (CV) measurements. In addition, a few similar glucose sensors based on graphene by chemical synthesis using modified Hummer's method were also fabricated for comparison.

Performance of Social Network Sensors during Hurricane Sandy

PubMed Central

Kryvasheyeu, Yury; Chen, Haohui; Moro, Esteban; Van Hentenryck, Pascal; Cebrian, Manuel

2015-01-01

Information flow during catastrophic events is a critical aspect of disaster management. Modern communication platforms, in particular online social networks, provide an opportunity to study such flow and derive early-warning sensors, thus improving emergency preparedness and response. Performance of the social networks sensor method, based on topological and behavioral properties derived from the “friendship paradox”, is studied here for over 50 million Twitter messages posted before, during, and after Hurricane Sandy. We find that differences in users’ network centrality effectively translate into moderate awareness advantage (up to 26 hours); and that geo-location of users within or outside of the hurricane-affected area plays a significant role in determining the scale of such an advantage. Emotional response appears to be universal regardless of the position in the network topology, and displays characteristic, easily detectable patterns, opening a possibility to implement a simple “sentiment sensing” technique that can detect and locate disasters. PMID:25692690

Pioneer Design of Non-contact Synchronized Measurement Devices Using Electric and Magnetic Field Sensors

DOE PAGES

Yao, Wenxuan; Zhang, Yingchen; Liu, Yong; ...

2017-04-10

Traditional synchrophasors rely on CTs and PTs physically connected to transmission lines or buses to acquire input signals for phasor measurement. However, it is challenging to install and maintain traditional phasor measurement units in some remote areas due to lack of facilities. Since transmission lines naturally generate alternating electrical and magnetic fields in the surrounding atmosphere, this paper presents two innovative designs for non-contact synchronized measurement devices (NCSMD), including an electric field sensor based non-contact SMD (E-NCSMD) and a magnetic field sensor based non-contact SMD (M-NCSMD). Compared with conventional synchrophasors, E-NCSMD and M-NCSMD are much more flexible to be deployedmore » and have much lower costs, making E-NCSMDs and M-NCSMD highly accessible and useful for a wide array of phasor measurement applications. Laboratory and field experiment results verified the effectiveness of the designs of both E-NCSMD and M-NCSMD.« less

Suborbital Science Program: Dryden Flight Research Center

NASA Technical Reports Server (NTRS)

DelFrate, John

2008-01-01

This viewgraph presentation reviews the suborbital science program at NASA Dryden Flight Research Center. The Program Objectives are given in various areas: (1) Satellite Calibration and Validation (Cal/val)--Provide methods to perform the cal/val requirements for Earth Observing System satellites; (2) New Sensor Development -- Provide methods to reduce risk for new sensor concepts and algorithm development prior to committing sensors to operations; (3) Process Studies -- Facilitate the acquisition of high spatial/temporal resolution focused measurements that are required to understand small atmospheric and surface structures which generate powerful Earth system effects; and (4) Airborne Networking -- Develop disruption-tolerant networking to enable integrated multiple scale measurements of critical environmental features. Dryden supports the NASA Airborne Science Program and the nation in several elements: ER-2, G-3, DC-8, Ikhana (Predator B) & Global Hawk and Reveal. These are reviewed in detail in the presentation.

Democratization of Nanoscale Imaging and Sensing Tools Using Photonics

PubMed Central

2015-01-01

Providing means for researchers and citizen scientists in the developing world to perform advanced measurements with nanoscale precision can help to accelerate the rate of discovery and invention as well as improve higher education and the training of the next generation of scientists and engineers worldwide. Here, we review some of the recent progress toward making optical nanoscale measurement tools more cost-effective, field-portable, and accessible to a significantly larger group of researchers and educators. We divide our review into two main sections: label-based nanoscale imaging and sensing tools, which primarily involve fluorescent approaches, and label-free nanoscale measurement tools, which include light scattering sensors, interferometric methods, photonic crystal sensors, and plasmonic sensors. For each of these areas, we have primarily focused on approaches that have either demonstrated operation outside of a traditional laboratory setting, including for example integration with mobile phones, or exhibited the potential for such operation in the near future. PMID:26068279

Construction and laboratory test of the fiber optic rotational seismograph FOSREM for rotational seismology area of interest

NASA Astrophysics Data System (ADS)

Kurzych, Anna; Jaroszewicz, Leszek R.; Kowalski, Jerzy K.

2017-05-01

A relatively young field of study named Rotational Seismology caused a highly interest in an investigation of rotational movements generated by earthquakes, explosions, and ambient vibrations. It includes a wide range of scientific branches. However, this field needs to apply appropriate rotational sensors which should fulfill restrict technical requirements. The presented in this work system FOSREM (Fibre-Optic System for Rotational Events and Phenomena Monitoring) seems to be a promising rotational sensor for such investigation. FOSREM works by measuring the Sagnac effect and generally consists of two basic elements: optical sensor and electronic part. Regarding to its theoretical sensitivity equals 2·10-8 rad/s/Hz1/2, it enables to measure rotation in a wide range of signal amplitude (10-8 rad/s ÷ 10 rad/s) and frequency (DC ÷ 328.12 Hz). Moreover, FOSREM is mobile and remotely controlled via Internet using a special designed software.

Characterization, monitoring, and sensor technology crosscutting program: Technology summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-06-01

The purpose of the Characterization, Monitoring, and Sensor Technology Crosscutting Program (CMST-CP) is to deliver appropriate characterization, monitoring, and sensor technology (CMST) to the Office of Waste Management (EM-30), the Office of Environmental Restoration (EM-40), and the Office of Facility Transition and Management (EM-60). The technology development must also be cost effective and appropriate to EM-30/40/60 needs. Furthermore, the required technologies must be delivered and implemented when needed. Accordingly, and to ensure that available DOE and other national resources are focused an the most pressing needs, management of the technology development is concentrated on the following Focus Areas: Contaminant Plumemore » Containment and Remediation (PFA); Landfill Stabilization (LSFA); High-Level Waste Tank Remediation (TFA); Mixed Waste Characterization, Treatment, and Disposal (MWFA); and Facility Deactivation, Decommissioning, and Material Disposition (FDDMDFA). Brief descriptions of CMST-CP projects funded in FY95 are presented.« less

Toward RADSCAT measurements over the sea and their interpretation

NASA Technical Reports Server (NTRS)

Claassen, J. P.; Fung, A. K.; Wu, S. T.; Chan, H. L.

1973-01-01

Investigations into several areas which are essential to the execution and interpretation of suborbital observations by composite radiometer - scatterometer sensor (RADSCAT) are reported. Experiments and theory were developed to demonstrate the remote anemometric capability of the sensor over the sea through various weather conditions. It is shown that weather situations found in extra tropical cyclones are useful for demonstrating the all weather capability of the composite sensor. The large scale fluctuations of the wind over the sea dictate the observational coverage required to correlate measurements with the mean surface wind speed. Various theoretical investigations were performed to establish a premise for the joint interpretation of the experiment data. The effects of clouds and rains on downward radiometric observations over the sea were computed. A method of predicting atmospheric attenuation from joint observations is developed. In other theoretical efforts, the emission and scattering characteristics of the sea were derived. Composite surface theories with coherent and noncoherent assumptions were employed.

Performance of social network sensors during Hurricane Sandy.

PubMed

Kryvasheyeu, Yury; Chen, Haohui; Moro, Esteban; Van Hentenryck, Pascal; Cebrian, Manuel

2015-01-01

Information flow during catastrophic events is a critical aspect of disaster management. Modern communication platforms, in particular online social networks, provide an opportunity to study such flow and derive early-warning sensors, thus improving emergency preparedness and response. Performance of the social networks sensor method, based on topological and behavioral properties derived from the "friendship paradox", is studied here for over 50 million Twitter messages posted before, during, and after Hurricane Sandy. We find that differences in users' network centrality effectively translate into moderate awareness advantage (up to 26 hours); and that geo-location of users within or outside of the hurricane-affected area plays a significant role in determining the scale of such an advantage. Emotional response appears to be universal regardless of the position in the network topology, and displays characteristic, easily detectable patterns, opening a possibility to implement a simple "sentiment sensing" technique that can detect and locate disasters.

Pioneer Design of Non-contact Synchronized Measurement Devices Using Electric and Magnetic Field Sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao, Wenxuan; Zhang, Yingchen; Liu, Yong

Traditional synchrophasors rely on CTs and PTs physically connected to transmission lines or buses to acquire input signals for phasor measurement. However, it is challenging to install and maintain traditional phasor measurement units in some remote areas due to lack of facilities. Since transmission lines naturally generate alternating electrical and magnetic fields in the surrounding atmosphere, this paper presents two innovative designs for non-contact synchronized measurement devices (NCSMD), including an electric field sensor based non-contact SMD (E-NCSMD) and a magnetic field sensor based non-contact SMD (M-NCSMD). Compared with conventional synchrophasors, E-NCSMD and M-NCSMD are much more flexible to be deployedmore » and have much lower costs, making E-NCSMDs and M-NCSMD highly accessible and useful for a wide array of phasor measurement applications. Laboratory and field experiment results verified the effectiveness of the designs of both E-NCSMD and M-NCSMD.« less

Democratization of Nanoscale Imaging and Sensing Tools Using Photonics.

PubMed

McLeod, Euan; Wei, Qingshan; Ozcan, Aydogan

2015-07-07

Providing means for researchers and citizen scientists in the developing world to perform advanced measurements with nanoscale precision can help to accelerate the rate of discovery and invention as well as improve higher education and the training of the next generation of scientists and engineers worldwide. Here, we review some of the recent progress toward making optical nanoscale measurement tools more cost-effective, field-portable, and accessible to a significantly larger group of researchers and educators. We divide our review into two main sections: label-based nanoscale imaging and sensing tools, which primarily involve fluorescent approaches, and label-free nanoscale measurement tools, which include light scattering sensors, interferometric methods, photonic crystal sensors, and plasmonic sensors. For each of these areas, we have primarily focused on approaches that have either demonstrated operation outside of a traditional laboratory setting, including for example integration with mobile phones, or exhibited the potential for such operation in the near future.

Material for surface-enhanced Raman spectroscopy, and SER sensors and method for preparing same

NASA Technical Reports Server (NTRS)

Farquharson, Stuart (Inventor); Nelson, Chad (Inventor); Lee, Yuan-Hsiang (Inventor)

2003-01-01

Metal-doped sol-gel materials, suitable for use as sensors for surface-enhanced Raman spectroscopic analysis for trace chemical detection, are produced by effecting gelation and solvent removal of a doped sol-gel under mild temperature conditions. At least in certain instances reaction and drying will desirably be effected in an oxygen-starved environment. The metal of the sol-gel material functions, when irradiated, to produce a plasmon field for interaction with molecules of an analyte in contact therewith, increasing by orders of magnitude Raman photons that are generate by excitation radiation, and the method allows matching of the metal and metal particle size to a wavelength of light (or incident radiation, e.g., laser radiation) to generate surface plasmons. The porosity of the sol-gel material dramatically increases the surface area, and thereby the amount of metal exposed for analyte interaction. The sensors provided may be in the form of glass vials, fiber optics, multi-well micro-sample plates, etc., having surface coatings of the doped sol-gel material, to provide sampling systems for use in a Raman instrument.

An Effective 3D Shape Descriptor for Object Recognition with RGB-D Sensors

PubMed Central

Liu, Zhong; Zhao, Changchen; Wu, Xingming; Chen, Weihai

2017-01-01

RGB-D sensors have been widely used in various areas of computer vision and graphics. A good descriptor will effectively improve the performance of operation. This article further analyzes the recognition performance of shape features extracted from multi-modality source data using RGB-D sensors. A hybrid shape descriptor is proposed as a representation of objects for recognition. We first extracted five 2D shape features from contour-based images and five 3D shape features over point cloud data to capture the global and local shape characteristics of an object. The recognition performance was tested for category recognition and instance recognition. Experimental results show that the proposed shape descriptor outperforms several common global-to-global shape descriptors and is comparable to some partial-to-global shape descriptors that achieved the best accuracies in category and instance recognition. Contribution of partial features and computational complexity were also analyzed. The results indicate that the proposed shape features are strong cues for object recognition and can be combined with other features to boost accuracy. PMID:28245553

γ-irradiation induced zinc ferrites and their enhanced room-temperature ammonia gas sensing properties

NASA Astrophysics Data System (ADS)

Raut, S. D.; Awasarmol, V. V.; Ghule, B. G.; Shaikh, S. F.; Gore, S. K.; Sharma, R. P.; Pawar, P. P.; Mane, R. S.

2018-03-01

Zinc ferrite (ZnFe2O4) nanoparticles (NPs), synthesized using a facile and cost-effective sol-gel auto-combustion method, were irradiated with 2 and 5 kGy γ-doses using 60Co as a radioactive source. Effect of γ-irradiation on the structure, morphology, pore-size and pore-volume and room-temperature (300 K) gas sensor performance has been measured and reported. Both as-synthesized and γ-irradiated ZnFe2O4 NPs reveal remarkable gas sensor activity to ammonia in contrast to methanol, ethanol, acetone and toluene volatile organic gases. The responses of pristine, 2 and 5 kGy γ-irradiated ZnFe2O4 NPs are respectively 55%, 66% and 81% @100 ppm concentration of ammonia, signifying an importance of γ-irradiation for enhancing the sensitivity, selectivity and stability of ZnFe2O4 NPs as ammonia gas sensors. Thereby, due to increase in surface area and crystallinity on γ-doses, the γ-irradiation improves the room-temperature ammonia gas sensing performance of ZnFe2O4.

Summary of Research 2000: Department of Oceanography

DTIC Science & Technology

2001-12-01

Castro, R., A. S. Mascarenhas, R. Durazo and C. Collins, "Variaci6n estacional de la temperatura y salinidad en la entrada del Golfo de California...AREAS: Sensors , Battlespace Environments KEYWORDS: Littoral, Acoustics, Nowcast, Shelfbreak Fronts NAVAL POSTGRADUATE SCHOOL OAO TEST-BAN TREATY...Organization. DoD KEY TECHNOLOGY AREAS: Sensors KEYWORDS: Nuclear Test-Ban Treaty Monitoring OCEAN ACOUSTIC FEDERATION: CALIFORNIA CURRENT MONITORING

The Node Deployment of Intelligent Sensor Networks Based on the Spatial Difference of Farmland Soil.

PubMed

Liu, Naisen; Cao, Weixing; Zhu, Yan; Zhang, Jingchao; Pang, Fangrong; Ni, Jun

2015-11-11

Considering that agricultural production is characterized by vast areas, scattered fields and long crop growth cycles, intelligent wireless sensor networks (WSNs) are suitable for monitoring crop growth information. Cost and coverage are the most key indexes for WSN applications. The differences in crop conditions are influenced by the spatial distribution of soil nutrients. If the nutrients are distributed evenly, the crop conditions are expected to be approximately uniform with little difference; on the contrary, there will be great differences in crop conditions. In accordance with the differences in the spatial distribution of soil information in farmland, fuzzy c-means clustering was applied to divide the farmland into several areas, where the soil fertility of each area is nearly uniform. Then the crop growth information in the area could be monitored with complete coverage by deploying a sensor node there, which could greatly decrease the deployed sensor nodes. Moreover, in order to accurately judge the optimal cluster number of fuzzy c-means clustering, a discriminant function for Normalized Intra-Cluster Coefficient of Variation (NICCV) was established. The sensitivity analysis indicates that NICCV is insensitive to the fuzzy weighting exponent, but it shows a strong sensitivity to the number of clusters.

In-Containment Signal Acquisition and Data Transmission via Power Lines within High Dose Areas of Nuclear Power Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mueller Steffen; Wibbing Sascha; Weigel Robert

2015-07-01

Signal acquisition and data transmission for innovative sensor systems and networks inside the containment of nuclear power plants (NPPs) is still a challenge with respect to safety, performance, reliability, availability, and costs. This especially applies to equipment upgrades for existing plants, special measurements, but also for new builds. This paper presents a novel method for efficient and cost-effective sensor signal acquisition and data transmission via power lines, in order to cope with the disadvantages of common system architectures that often suffer from poor signal integrity due to raw data transmissions via long cables, huge efforts and costs for installation, andmore » low flexibility with respect to maintenance and upgrades. A transmitter-receiver architecture is proposed that allows multiplexing of multiple sensor inputs for unidirectional point-to-point transmission by superimposing information signals on existing AC or DC supply lines, but also on active and inactive sensor wires, or spare cables, using power line communication (PLC) technology. Based on commercial off-the-shelf (COTS) electronic parts, a radiation hard transmitter hardware is designed to operate in harsh environment within the containment during full plant operation. The system's modular approach allows application specific trade-offs between redundancy and throughput regarding data transmission, as well as various sensor input front-ends which are compatible with state of the art systems. PLC technology eliminates the need for costly installation of additional cables and wall penetrations, while providing a complementary and diverse communication technology for upgrades of existing systems. At the receiver side in low dose areas, signals are extracted from the power line, demodulated, and de-multiplexed, in order to regain the original sensor signal information and provide it either in analog or digital output format. Successful laboratory qualification tests, field trails, and a demonstrator setup installation within a NPP verify the overall performance of the proposed system. (authors)« less

Sensor-Aware Recognition and Tracking for Wide-Area Augmented Reality on Mobile Phones

PubMed Central

Chen, Jing; Cao, Ruochen; Wang, Yongtian

2015-01-01

Wide-area registration in outdoor environments on mobile phones is a challenging task in mobile augmented reality fields. We present a sensor-aware large-scale outdoor augmented reality system for recognition and tracking on mobile phones. GPS and gravity information is used to improve the VLAD performance for recognition. A kind of sensor-aware VLAD algorithm, which is self-adaptive to different scale scenes, is utilized to recognize complex scenes. Considering vision-based registration algorithms are too fragile and tend to drift, data coming from inertial sensors and vision are fused together by an extended Kalman filter (EKF) to achieve considerable improvements in tracking stability and robustness. Experimental results show that our method greatly enhances the recognition rate and eliminates the tracking jitters. PMID:26690439

Sensor-Aware Recognition and Tracking for Wide-Area Augmented Reality on Mobile Phones.

PubMed

Chen, Jing; Cao, Ruochen; Wang, Yongtian

2015-12-10

Wide-area registration in outdoor environments on mobile phones is a challenging task in mobile augmented reality fields. We present a sensor-aware large-scale outdoor augmented reality system for recognition and tracking on mobile phones. GPS and gravity information is used to improve the VLAD performance for recognition. A kind of sensor-aware VLAD algorithm, which is self-adaptive to different scale scenes, is utilized to recognize complex scenes. Considering vision-based registration algorithms are too fragile and tend to drift, data coming from inertial sensors and vision are fused together by an extended Kalman filter (EKF) to achieve considerable improvements in tracking stability and robustness. Experimental results show that our method greatly enhances the recognition rate and eliminates the tracking jitters.

The Integrated Radiation Mapper Assistant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlton, R.E.; Tripp, L.R.

1995-03-01

The Integrated Radiation Mapper Assistant (IRMA) system combines state-of-the-art radiation sensors and microprocessor based analysis techniques to perform radiation surveys. Control of the survey function is from a control station located outside the radiation thus reducing time spent in radiation areas performing radiation surveys. The system consists of a directional radiation sensor, a laser range finder, two area radiation sensors, and a video camera mounted on a pan and tilt platform. THis sensor package is deployable on a remotely operated vehicle. The outputs of the system are radiation intensity maps identifying both radiation source intensities and radiation levels throughout themore » room being surveyed. After completion of the survey, the data can be removed from the control station computer for further analysis or archiving.« less

Influence of IR sensor technology on the military and civil defense

NASA Astrophysics Data System (ADS)

Becker, Latika

2006-02-01

Advances in basic infrared science and developments in pertinent technology applications have led to mature designs being incorporated in civil as well as military area defense systems. Military systems include both tactical and strategic, and civil area defense includes homeland security. Technical challenges arise in applying infrared sensor technology to detect and track targets for space and missile defense. Infrared sensors are valuable due to their passive capability, lower mass and power consumption, and their usefulness in all phases of missile defense engagements. Nanotechnology holds significant promise in the near future by offering unique material and physical properties to infrared components. This technology is rapidly developing. This presentation will review the current IR sensor technology, its applications, and future developments that will have an influence in military and civil defense applications.