Implementation study of wearable sensors for activity recognition systems

PubMed Central

Ghassemian, Mona

2015-01-01

This Letter investigates and reports on a number of activity recognition methods for a wearable sensor system. The authors apply three methods for data transmission, namely ‘stream-based’, ‘feature-based’ and ‘threshold-based’ scenarios to study the accuracy against energy efficiency of transmission and processing power that affects the mote's battery lifetime. They also report on the impact of variation of sampling frequency and data transmission rate on energy consumption of motes for each method. This study leads us to propose a cross-layer optimisation of an activity recognition system for provisioning acceptable levels of accuracy and energy efficiency. PMID:26609413

Dense range map reconstruction from a versatile robotic sensor system with an active trinocular vision and a passive binocular vision.

PubMed

Kim, Min Young; Lee, Hyunkee; Cho, Hyungsuck

2008-04-10

One major research issue associated with 3D perception by robotic systems is the creation of efficient sensor systems that can generate dense range maps reliably. A visual sensor system for robotic applications is developed that is inherently equipped with two types of sensor, an active trinocular vision and a passive stereo vision. Unlike in conventional active vision systems that use a large number of images with variations of projected patterns for dense range map acquisition or from conventional passive vision systems that work well on specific environments with sufficient feature information, a cooperative bidirectional sensor fusion method for this visual sensor system enables us to acquire a reliable dense range map using active and passive information simultaneously. The fusion algorithms are composed of two parts, one in which the passive stereo vision helps active vision and the other in which the active trinocular vision helps the passive one. The first part matches the laser patterns in stereo laser images with the help of intensity images; the second part utilizes an information fusion technique using the dynamic programming method in which image regions between laser patterns are matched pixel-by-pixel with help of the fusion results obtained in the first part. To determine how the proposed sensor system and fusion algorithms can work in real applications, the sensor system is implemented on a robotic system, and the proposed algorithms are applied. A series of experimental tests is performed for a variety of configurations of robot and environments. The performance of the sensor system is discussed in detail.

A triboelectric motion sensor in wearable body sensor network for human activity recognition.

PubMed

Hui Huang; Xian Li; Ye Sun

2016-08-01

The goal of this study is to design a novel triboelectric motion sensor in wearable body sensor network for human activity recognition. Physical activity recognition is widely used in well-being management, medical diagnosis and rehabilitation. Other than traditional accelerometers, we design a novel wearable sensor system based on triboelectrification. The triboelectric motion sensor can be easily attached to human body and collect motion signals caused by physical activities. The experiments are conducted to collect five common activity data: sitting and standing, walking, climbing upstairs, downstairs, and running. The k-Nearest Neighbor (kNN) clustering algorithm is adopted to recognize these activities and validate the feasibility of this new approach. The results show that our system can perform physical activity recognition with a successful rate over 80% for walking, sitting and standing. The triboelectric structure can also be used as an energy harvester for motion harvesting due to its high output voltage in random low-frequency motion.

A depth video sensor-based life-logging human activity recognition system for elderly care in smart indoor environments.

PubMed

Jalal, Ahmad; Kamal, Shaharyar; Kim, Daijin

2014-07-02

Recent advancements in depth video sensors technologies have made human activity recognition (HAR) realizable for elderly monitoring applications. Although conventional HAR utilizes RGB video sensors, HAR could be greatly improved with depth video sensors which produce depth or distance information. In this paper, a depth-based life logging HAR system is designed to recognize the daily activities of elderly people and turn these environments into an intelligent living space. Initially, a depth imaging sensor is used to capture depth silhouettes. Based on these silhouettes, human skeletons with joint information are produced which are further used for activity recognition and generating their life logs. The life-logging system is divided into two processes. Firstly, the training system includes data collection using a depth camera, feature extraction and training for each activity via Hidden Markov Models. Secondly, after training, the recognition engine starts to recognize the learned activities and produces life logs. The system was evaluated using life logging features against principal component and independent component features and achieved satisfactory recognition rates against the conventional approaches. Experiments conducted on the smart indoor activity datasets and the MSRDailyActivity3D dataset show promising results. The proposed system is directly applicable to any elderly monitoring system, such as monitoring healthcare problems for elderly people, or examining the indoor activities of people at home, office or hospital.

A Depth Video Sensor-Based Life-Logging Human Activity Recognition System for Elderly Care in Smart Indoor Environments

PubMed Central

Jalal, Ahmad; Kamal, Shaharyar; Kim, Daijin

2014-01-01

Recent advancements in depth video sensors technologies have made human activity recognition (HAR) realizable for elderly monitoring applications. Although conventional HAR utilizes RGB video sensors, HAR could be greatly improved with depth video sensors which produce depth or distance information. In this paper, a depth-based life logging HAR system is designed to recognize the daily activities of elderly people and turn these environments into an intelligent living space. Initially, a depth imaging sensor is used to capture depth silhouettes. Based on these silhouettes, human skeletons with joint information are produced which are further used for activity recognition and generating their life logs. The life-logging system is divided into two processes. Firstly, the training system includes data collection using a depth camera, feature extraction and training for each activity via Hidden Markov Models. Secondly, after training, the recognition engine starts to recognize the learned activities and produces life logs. The system was evaluated using life logging features against principal component and independent component features and achieved satisfactory recognition rates against the conventional approaches. Experiments conducted on the smart indoor activity datasets and the MSRDailyActivity3D dataset show promising results. The proposed system is directly applicable to any elderly monitoring system, such as monitoring healthcare problems for elderly people, or examining the indoor activities of people at home, office or hospital. PMID:24991942

Dealing with the Effects of Sensor Displacement in Wearable Activity Recognition

PubMed Central

Banos, Oresti; Toth, Mate Attila; Damas, Miguel; Pomares, Hector; Rojas, Ignacio

2014-01-01

Most wearable activity recognition systems assume a predefined sensor deployment that remains unchanged during runtime. However, this assumption does not reflect real-life conditions. During the normal use of such systems, users may place the sensors in a position different from the predefined sensor placement. Also, sensors may move from their original location to a different one, due to a loose attachment. Activity recognition systems trained on activity patterns characteristic of a given sensor deployment may likely fail due to sensor displacements. In this work, we innovatively explore the effects of sensor displacement induced by both the intentional misplacement of sensors and self-placement by the user. The effects of sensor displacement are analyzed for standard activity recognition techniques, as well as for an alternate robust sensor fusion method proposed in a previous work. While classical recognition models show little tolerance to sensor displacement, the proposed method is proven to have notable capabilities to assimilate the changes introduced in the sensor position due to self-placement and provides considerable improvements for large misplacements. PMID:24915181

Smart Sensor Systems for Aerospace Applications: From Sensor Development to Application Testing

NASA Technical Reports Server (NTRS)

Hunter, G. W.; Xu, J. C.; Dungan, L. K.; Ward, B. J.; Rowe, S.; Williams, J.; Makel, D. B.; Liu, C. C.; Chang, C. W.

2008-01-01

The application of Smart Sensor Systems for aerospace applications is a multidisciplinary process consisting of sensor element development, element integration into Smart Sensor hardware, and testing of the resulting sensor systems in application environments. This paper provides a cross-section of these activities for multiple aerospace applications illustrating the technology challenges involved. The development and application testing topics discussed are: 1) The broadening of sensitivity and operational range of silicon carbide (SiC) Schottky gas sensor elements; 2) Integration of fire detection sensor technology into a "Lick and Stick" Smart Sensor hardware platform for Crew Exploration Vehicle applications; 3) Extended testing for zirconia based oxygen sensors in the basic "Lick and Stick" platform for environmental monitoring applications. It is concluded that that both core sensor platform technology and a basic hardware platform can enhance the viability of implementing smart sensor systems in aerospace applications.

Embedded Triboelectric Active Sensors for Real-Time Pneumatic Monitoring.

PubMed

Fu, Xian Peng; Bu, Tian Zhao; Xi, Feng Ben; Cheng, Ting Hai; Zhang, Chi; Wang, Zhong Lin

2017-09-20

Pneumatic monitoring sensors have great demands for power supply in cylinder systems. Here, we present an embedded sliding triboelectric nanogenerator (TENG) in air cylinder as active sensors for position and velocity monitoring. The embedded TENG is composed of a circular poly(tetrafluoroethylene) polymer and a triangular copper electrode. The working mechanism as triboelectric active sensors and electric output performance are systematically investigated. By integrating into the pneumatic system, the embedded triboelectric active sensors have been used for real-time air pressure/flow monitoring and energy storage. Air pressures are measured from 0.04 to 0.12 MPa at a step of 0.02 MPa with a sensitivity of 49.235 V/MPa, as well as airflow from 50 to 250 L/min at a step of 50 L/min with a sensitivity of 0.002 μA·min/L. This work has first demonstrated triboelectric active sensors for pneumatic monitoring and may promote the development of TENG in intelligent pneumatic system.

Inertial navigation sensor integrated obstacle detection system

NASA Technical Reports Server (NTRS)

Bhanu, Bir (Inventor); Roberts, Barry A. (Inventor)

1992-01-01

A system that incorporates inertial sensor information into optical flow computations to detect obstacles and to provide alternative navigational paths free from obstacles. The system is a maximally passive obstacle detection system that makes selective use of an active sensor. The active detection typically utilizes a laser. Passive sensor suite includes binocular stereo, motion stereo and variable fields-of-view. Optical flow computations involve extraction, derotation and matching of interest points from sequential frames of imagery, for range interpolation of the sensed scene, which in turn provides obstacle information for purposes of safe navigation.

A general framework for sensor-based human activity recognition.

PubMed

Köping, Lukas; Shirahama, Kimiaki; Grzegorzek, Marcin

2018-04-01

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

A biomedical sensor system for real-time monitoring of astronauts' physiological parameters during extra-vehicular activities.

PubMed

Fei, Ding-Yu; Zhao, Xiaoming; Boanca, Cosmin; Hughes, Esther; Bai, Ou; Merrell, Ronald; Rafiq, Azhar

2010-07-01

To design and test an embedded biomedical sensor system that can monitor astronauts' comprehensive physiological parameters, and provide real-time data display during extra-vehicle activities (EVA) in the space exploration. An embedded system was developed with an array of biomedical sensors that can be integrated into the spacesuit. Wired communications were tested for physiological data acquisition and data transmission to a computer mounted on the spacesuit during task performances simulating EVA sessions. The sensor integration, data collection and communication, and the real-time data monitoring were successfully validated in the NASA field tests. The developed system may work as an embedded system for monitoring health status during long-term space mission. Copyright 2010 Elsevier Ltd. All rights reserved.

Ultrasonic sensors in urban traffic driving-aid systems.

PubMed

Alonso, Luciano; Milanés, Vicente; Torre-Ferrero, Carlos; Godoy, Jorge; Oria, Juan P; de Pedro, Teresa

2011-01-01

Currently, vehicles are often equipped with active safety systems to reduce the risk of accidents, most of which occur in urban environments. The most prominent include Antilock Braking Systems (ABS), Traction Control and Stability Control. All these systems use different kinds of sensors to constantly monitor the conditions of the vehicle, and act in an emergency. In this paper the use of ultrasonic sensors in active safety systems for urban traffic is proposed, and the advantages and disadvantages when compared to other sensors are discussed. Adaptive Cruise Control (ACC) for urban traffic based on ultrasounds is presented as an application example. The proposed system has been implemented in a fully-automated prototype vehicle and has been tested under real traffic conditions. The results confirm the good performance of ultrasonic sensors in these systems.

Ultrasonic Sensors in Urban Traffic Driving-Aid Systems

PubMed Central

Alonso, Luciano; Milanés, Vicente; Torre-Ferrero, Carlos; Godoy, Jorge; Oria, Juan P.; de Pedro, Teresa

2011-01-01

Currently, vehicles are often equipped with active safety systems to reduce the risk of accidents, most of which occur in urban environments. The most prominent include Antilock Braking Systems (ABS), Traction Control and Stability Control. All these systems use different kinds of sensors to constantly monitor the conditions of the vehicle, and act in an emergency. In this paper the use of ultrasonic sensors in active safety systems for urban traffic is proposed, and the advantages and disadvantages when compared to other sensors are discussed. Adaptive Cruise Control (ACC) for urban traffic based on ultrasounds is presented as an application example. The proposed system has been implemented in a fully-automated prototype vehicle and has been tested under real traffic conditions. The results confirm the good performance of ultrasonic sensors in these systems. PMID:22346596

Multi-sensor physical activity recognition in free-living.

PubMed

Ellis, Katherine; Godbole, Suneeta; Kerr, Jacqueline; Lanckriet, Gert

Physical activity monitoring in free-living populations has many applications for public health research, weight-loss interventions, context-aware recommendation systems and assistive technologies. We present a system for physical activity recognition that is learned from a free-living dataset of 40 women who wore multiple sensors for seven days. The multi-level classification system first learns low-level codebook representations for each sensor and uses a random forest classifier to produce minute-level probabilities for each activity class. Then a higher-level HMM layer learns patterns of transitions and durations of activities over time to smooth the minute-level predictions. [Formula: see text].

Low-Cost Sensor System Design for In-Home Physical Activity Tracking.

PubMed

Nambiar, Siddhartha; Nikolaev, Alexander; Greene, Melissa; Cavuoto, Lora; Bisantz, Ann

2016-01-01

An aging and more sedentary population requires interventions aimed at monitoring physical activity, particularly within the home. This research uses simulation, optimization, and regression analyses to assess the feasibility of using a small number of sensors to track movement and infer physical activity levels of older adults. Based on activity data from the American Time Use Survey and assisted living apartment layouts, we determined that using three to four doorway sensors can be used to effectively capture a sufficient amount of movements in order to estimate activity. The research also identified preferred approaches for assigning sensor locations, evaluated the error magnitude inherent in the approach, and developed a methodology to identify which apartment layouts would be best suited for these technologies.

Low-Cost Sensor System Design for In-Home Physical Activity Tracking

PubMed Central

Nikolaev, Alexander; Greene, Melissa; Cavuoto, Lora; Bisantz, Ann

2016-01-01

An aging and more sedentary population requires interventions aimed at monitoring physical activity, particularly within the home. This research uses simulation, optimization, and regression analyses to assess the feasibility of using a small number of sensors to track movement and infer physical activity levels of older adults. Based on activity data from the American Time Use Survey and assisted living apartment layouts, we determined that using three to four doorway sensors can be used to effectively capture a sufficient amount of movements in order to estimate activity. The research also identified preferred approaches for assigning sensor locations, evaluated the error magnitude inherent in the approach, and developed a methodology to identify which apartment layouts would be best suited for these technologies. PMID:28560118

16 CFR 1211.13 - Inherent force activated secondary door sensors.

Code of Federal Regulations, 2011 CFR

2011-01-01

... sensors. 1211.13 Section 1211.13 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT... § 1211.13 Inherent force activated secondary door sensors. (a) Normal operation test. (1) A force activated door sensor of a door system installed according to the installation instructions shall actuate...

16 CFR 1211.13 - Inherent force activated secondary door sensors.

Code of Federal Regulations, 2014 CFR

2014-01-01

... sensors. 1211.13 Section 1211.13 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT... § 1211.13 Inherent force activated secondary door sensors. (a) Normal operation test. (1) A force activated door sensor of a door system installed according to the installation instructions shall actuate...

16 CFR 1211.13 - Inherent force activated secondary door sensors.

Code of Federal Regulations, 2012 CFR

2012-01-01

... sensors. 1211.13 Section 1211.13 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT... § 1211.13 Inherent force activated secondary door sensors. (a) Normal operation test. (1) A force activated door sensor of a door system installed according to the installation instructions shall actuate...

Extracting aerobic system dynamics during unsupervised activities of daily living using wearable sensor machine learning models.

PubMed

Beltrame, Thomas; Amelard, Robert; Wong, Alexander; Hughson, Richard L

2018-02-01

Physical activity levels are related through algorithms to the energetic demand, with no information regarding the integrity of the multiple physiological systems involved in the energetic supply. Longitudinal analysis of the oxygen uptake (V̇o 2 ) by wearable sensors in realistic settings might permit development of a practical tool for the study of the longitudinal aerobic system dynamics (i.e., V̇o 2 kinetics). This study evaluated aerobic system dynamics based on predicted V̇o 2 data obtained from wearable sensors during unsupervised activities of daily living (μADL). Thirteen healthy men performed a laboratory-controlled moderate exercise protocol and were monitored for ≈6 h/day for 4 days (μADL data). Variables derived from hip accelerometer (ACC HIP ), heart rate monitor, and respiratory bands during μADL were extracted and processed by a validated random forest regression model to predict V̇o 2 . The aerobic system analysis was based on the frequency-domain analysis of ACC HIP and predicted V̇o 2 data obtained during μADL. Optimal samples for frequency domain analysis (constrained to ≤0.01 Hz) were selected when ACC HIP was higher than 0.05 g at a given frequency (i.e., participants were active). The temporal characteristics of predicted V̇o 2 data during μADL correlated with the temporal characteristics of measured V̇o 2 data during laboratory-controlled protocol ([Formula: see text] = 0.82, P < 0.001, n = 13). In conclusion, aerobic system dynamics can be investigated during unsupervised activities of daily living by wearable sensors. Although speculative, these algorithms have the potential to be incorporated into wearable systems for early detection of changes in health status in realistic environments by detecting changes in aerobic response dynamics. NEW & NOTEWORTHY The early detection of subclinical aerobic system impairments might be indicative of impaired physiological reserves that impact the capacity for physical activity

Feasibility testing of a home-based sensor system to monitor mobility and daily activities in Korean American older adults.

PubMed

Chung, Jane; Demiris, George; Thompson, Hilaire J; Chen, Ke-Yu; Burr, Robert; Patel, Shwetak; Fogarty, James

2017-03-01

This study aimed to test feasibility of a home-based sensor system that is designed to assess mobility and daily activity patterns among Korean American older adults (KAOAs; n = 6) and explore sensor technology acceptance among participants. Home-based sensors have the potential to support older adults' desire to remain at home as long as possible. Despite a growing interest in using home-based sensors for older adults, there have been no documented attempts to apply this type of technology to a group of ethnic minority older adults. The study employed descriptive, quantitative and qualitative approaches. The system was deployed for 2 months in four homes of KAOAs. Study procedures included (i) sensor-based data collection, (ii) self-report mobility instruments, (iii) activity logs and (iv) interviews. To explore changes in activity patterns, line graphs and sequence plots were applied to data obtained from a set of sensors. General linear models (GLMs) were used for motion in each space of the home to examine how much variability of activities is explained by several time variables. Sensor data had natural fluctuation over time. Different 24-hr patterns were observed across homes. The GLM estimates showed that effect sizes of the time variables vary across individuals. A hydro sensor deployed in one participant's bathroom inferred various water usage activities. Overall, sensors were acceptable for all participants, despite some privacy concerns. Study findings demonstrate that sensor technology applications could be successfully used longitudinally in a minority population of older adults that is not often targeted as an end-user group for the use of innovative technologies. The use of home-based sensors provides nurses with a useful tool to detect deviations from normal patterns and to achieve proactive care for some groups of older adults. © 2016 John Wiley & Sons Ltd.

Alternative sensor system and MLP neural network for vehicle pedal activity estimation.

PubMed

Wefky, Ahmed M; Espinosa, Felipe; Jiménez, José A; Santiso, Enrique; Rodríguez, José M; Fernández, Alfredo J

2010-01-01

It is accepted that the activity of the vehicle pedals (i.e., throttle, brake, clutch) reflects the driver's behavior, which is at least partially related to the fuel consumption and vehicle pollutant emissions. This paper presents a solution to estimate the driver activity regardless of the type, model, and year of fabrication of the vehicle. The solution is based on an alternative sensor system (regime engine, vehicle speed, frontal inclination and linear acceleration) that reflects the activity of the pedals in an indirect way, to estimate that activity by means of a multilayer perceptron neural network with a single hidden layer.

Hand tremor and activity sensor

NASA Technical Reports Server (NTRS)

Konigsberg, E.

1975-01-01

System detects hand tremor and activity and transmitting signals over distance of at least 3 meters to receiver system. Designed for use in studies of effect of fatigue on individual's judgement or reaction time, sensor is installed within mounting of finger-ring; no external wiring or power source is needed.

Structural integrated sensor and actuator systems for active flow control

NASA Astrophysics Data System (ADS)

Behr, Christian; Schwerter, Martin; Leester-Schädel, Monika; Wierach, Peter; Dietzel, Andreas; Sinapius, Michael

2016-04-01

An adaptive flow separation control system is designed and implemented as an essential part of a novel high-lift device for future aircraft. The system consists of MEMS pressure sensors to determine the flow conditions and adaptive lips to regulate the mass flow and the velocity of a wall near stream over the internally blown Coanda flap. By the oscillating lip the mass flow in the blowing slot changes dynamically, consequently the momentum exchange of the boundary layer over a high lift flap required mass flow can be reduced. These new compact and highly integrated systems provide a real-time monitoring and manipulation of the flow conditions. In this context the integration of pressure sensors into flow sensing airfoils of composite material is investigated. Mechanical and electrical properties of the integrated sensors are investigated under mechanical loads during tensile tests. The sensors contain a reference pressure chamber isolated to the ambient by a deformable membrane with integrated piezoresistors connected as a Wheatstone bridge, which outputs voltage signals depending on the ambient pressure. The composite material in which the sensors are embedded consists of 22 individual layers of unidirectional glass fiber reinforced plastic (GFRP) prepreg. The results of the experiments are used for adapting the design of the sensors and the layout of the laminate to ensure an optimized flux of force in highly loaded structures primarily for future aeronautical applications. It can be shown that the pressure sensor withstands the embedding process into fiber composites with full functional capability and predictable behavior under stress.

CMOS Active Pixel Sensor Star Tracker with Regional Electronic Shutter

NASA Technical Reports Server (NTRS)

Yadid-Pecht, Orly; Pain, Bedabrata; Staller, Craig; Clark, Christopher; Fossum, Eric

1996-01-01

The guidance system in a spacecraft determines spacecraft attitude by matching an observed star field to a star catalog....An APS(active pixel sensor)-based system can reduce mass and power consumption and radiation effects compared to a CCD(charge-coupled device)-based system...This paper reports an APS (active pixel sensor) with locally variable times, achieved through individual pixel reset (IPR).

Alternative Sensor System and MLP Neural Network for Vehicle Pedal Activity Estimation

PubMed Central

Wefky, Ahmed M.; Espinosa, Felipe; Jiménez, José A.; Santiso, Enrique; Rodríguez, José M.; Fernández, Alfredo J.

2010-01-01

It is accepted that the activity of the vehicle pedals (i.e., throttle, brake, clutch) reflects the driver’s behavior, which is at least partially related to the fuel consumption and vehicle pollutant emissions. This paper presents a solution to estimate the driver activity regardless of the type, model, and year of fabrication of the vehicle. The solution is based on an alternative sensor system (regime engine, vehicle speed, frontal inclination and linear acceleration) that reflects the activity of the pedals in an indirect way, to estimate that activity by means of a multilayer perceptron neural network with a single hidden layer. PMID:22319326

Aerospace Sensor Systems: From Sensor Development To Vehicle Application

NASA Technical Reports Server (NTRS)

Hunter, Gary W.

2008-01-01

This paper presents an overview of years of sensor system development and application for aerospace systems. The emphasis of this work is on developing advanced capabilities for measurement and control of aeropropulsion and crew vehicle systems as well as monitoring the safety of those systems. Specific areas of work include chemical species sensors, thin film thermocouples and strain gages, heat flux gages, fuel gages, SiC based electronic devices and sensors, space qualified electronics, and MicroElectroMechanical Systems (MEMS) as well as integrated and multifunctional sensor systems. Each sensor type has its own technical challenges related to integration and reliability in a given application. The general approach has been to develop base sensor technology using microfabrication techniques, integrate sensors with "smart" hardware and software, and demonstrate those systems in a range of aerospace applications. Descriptions of the sensor elements, their integration into sensors systems, and examples of sensor system applications will be discussed. Finally, suggestions related to the future of sensor technology will be given. It is concluded that smart micro/nano sensor technology can revolutionize aerospace applications, but significant challenges exist in maturing the technology and demonstrating its value in real-life applications.

An Intelligent Active Video Surveillance System Based on the Integration of Virtual Neural Sensors and BDI Agents

NASA Astrophysics Data System (ADS)

Gregorio, Massimo De

In this paper we present an intelligent active video surveillance system currently adopted in two different application domains: railway tunnels and outdoor storage areas. The system takes advantages of the integration of Artificial Neural Networks (ANN) and symbolic Artificial Intelligence (AI). This hybrid system is formed by virtual neural sensors (implemented as WiSARD-like systems) and BDI agents. The coupling of virtual neural sensors with symbolic reasoning for interpreting their outputs, makes this approach both very light from a computational and hardware point of view, and rather robust in performances. The system works on different scenarios and in difficult light conditions.

16 CFR § 1211.13 - Inherent force activated secondary door sensors.

Code of Federal Regulations, 2013 CFR

2013-01-01

... sensors. § 1211.13 Section § 1211.13 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER... Standard § 1211.13 Inherent force activated secondary door sensors. (a) Normal operation test. (1) A force activated door sensor of a door system installed according to the installation instructions shall actuate...

Active pixel sensors with substantially planarized color filtering elements

NASA Technical Reports Server (NTRS)

Fossum, Eric R. (Inventor); Kemeny, Sabrina E. (Inventor)

1999-01-01

A semiconductor imaging system preferably having an active pixel sensor array compatible with a CMOS fabrication process. Color-filtering elements such as polymer filters and wavelength-converting phosphors can be integrated with the image sensor.

Passive wireless sensor systems can recognize activites of daily living.

PubMed

Urwyler, Prabitha; Stucki, Reto; Muri, Rene; Mosimann, Urs P; Nef, Tobias

2015-08-01

The ability to determine what activity of daily living a person performs is of interest in many application domains. It is possible to determine the physical and cognitive capabilities of the elderly by inferring what activities they perform in their houses. Our primary aim was to establish a proof of concept that a wireless sensor system can monitor and record physical activity and these data can be modeled to predict activities of daily living. The secondary aim was to determine the optimal placement of the sensor boxes for detecting activities in a room. A wireless sensor system was set up in a laboratory kitchen. The ten healthy participants were requested to make tea following a defined sequence of tasks. Data were collected from the eight wireless sensor boxes placed in specific places in the test kitchen and analyzed to detect the sequences of tasks performed by the participants. These sequence of tasks were trained and tested using the Markov Model. Data analysis focused on the reliability of the system and the integrity of the collected data. The sequence of tasks were successfully recognized for all subjects and the averaged data pattern of tasks sequences between the subjects had a high correlation. Analysis of the data collected indicates that sensors placed in different locations are capable of recognizing activities, with the movement detection sensor contributing the most to detection of tasks. The central top of the room with no obstruction of view was considered to be the best location to record data for activity detection. Wireless sensor systems show much promise as easily deployable to monitor and recognize activities of daily living.

Collegial Activity Learning between Heterogeneous Sensors.

PubMed

Feuz, Kyle D; Cook, Diane J

2017-11-01

Activity recognition algorithms have matured and become more ubiquitous in recent years. However, these algorithms are typically customized for a particular sensor platform. In this paper we introduce PECO, a Personalized activity ECOsystem, that transfers learned activity information seamlessly between sensor platforms in real time so that any available sensor can continue to track activities without requiring its own extensive labeled training data. We introduce a multi-view transfer learning algorithm that facilitates this information handoff between sensor platforms and provide theoretical performance bounds for the algorithm. In addition, we empirically evaluate PECO using datasets that utilize heterogeneous sensor platforms to perform activity recognition. These results indicate that not only can activity recognition algorithms transfer important information to new sensor platforms, but any number of platforms can work together as colleagues to boost performance.

Airborne laser sensors and integrated systems

NASA Astrophysics Data System (ADS)

Sabatini, Roberto; Richardson, Mark A.; Gardi, Alessandro; Ramasamy, Subramanian

2015-11-01

The underlying principles and technologies enabling the design and operation of airborne laser sensors are introduced and a detailed review of state-of-the-art avionic systems for civil and military applications is presented. Airborne lasers including Light Detection and Ranging (LIDAR), Laser Range Finders (LRF), and Laser Weapon Systems (LWS) are extensively used today and new promising technologies are being explored. Most laser systems are active devices that operate in a manner very similar to microwave radars but at much higher frequencies (e.g., LIDAR and LRF). Other devices (e.g., laser target designators and beam-riders) are used to precisely direct Laser Guided Weapons (LGW) against ground targets. The integration of both functions is often encountered in modern military avionics navigation-attack systems. The beneficial effects of airborne lasers including the use of smaller components and remarkable angular resolution have resulted in a host of manned and unmanned aircraft applications. On the other hand, laser sensors performance are much more sensitive to the vagaries of the atmosphere and are thus generally restricted to shorter ranges than microwave systems. Hence it is of paramount importance to analyse the performance of laser sensors and systems in various weather and environmental conditions. Additionally, it is important to define airborne laser safety criteria, since several systems currently in service operate in the near infrared with considerable risk for the naked human eye. Therefore, appropriate methods for predicting and evaluating the performance of infrared laser sensors/systems are presented, taking into account laser safety issues. For aircraft experimental activities with laser systems, it is essential to define test requirements taking into account the specific conditions for operational employment of the systems in the intended scenarios and to verify the performance in realistic environments at the test ranges. To support the

Implementation of accelerometer sensor module and fall detection monitoring system based on wireless sensor network.

PubMed

Lee, Youngbum; Kim, Jinkwon; Son, Muntak; Lee, Myoungho

2007-01-01

This research implements wireless accelerometer sensor module and algorithm to determine wearer's posture, activity and fall. Wireless accelerometer sensor module uses ADXL202, 2-axis accelerometer sensor (Analog Device). And using wireless RF module, this module measures accelerometer signal and shows the signal at ;Acceloger' viewer program in PC. ADL algorithm determines posture, activity and fall that activity is determined by AC component of accelerometer signal and posture is determined by DC component of accelerometer signal. Those activity and posture include standing, sitting, lying, walking, running, etc. By the experiment for 30 subjects, the performance of implemented algorithm was assessed, and detection rate for postures, motions and subjects was calculated. Lastly, using wireless sensor network in experimental space, subject's postures, motions and fall monitoring system was implemented. By the simulation experiment for 30 subjects, 4 kinds of activity, 3 times, fall detection rate was calculated. In conclusion, this system can be application to patients and elders for activity monitoring and fall detection and also sports athletes' exercise measurement and pattern analysis. And it can be expected to common person's exercise training and just plaything for entertainment.

Activity Recognition on Streaming Sensor Data.

PubMed

Krishnan, Narayanan C; Cook, Diane J

2014-02-01

Many real-world applications that focus on addressing needs of a human, require information about the activities being performed by the human in real-time. While advances in pervasive computing have lead to the development of wireless and non-intrusive sensors that can capture the necessary activity information, current activity recognition approaches have so far experimented on either a scripted or pre-segmented sequence of sensor events related to activities. In this paper we propose and evaluate a sliding window based approach to perform activity recognition in an on line or streaming fashion; recognizing activities as and when new sensor events are recorded. To account for the fact that different activities can be best characterized by different window lengths of sensor events, we incorporate the time decay and mutual information based weighting of sensor events within a window. Additional contextual information in the form of the previous activity and the activity of the previous window is also appended to the feature describing a sensor window. The experiments conducted to evaluate these techniques on real-world smart home datasets suggests that combining mutual information based weighting of sensor events and adding past contextual information into the feature leads to best performance for streaming activity recognition.

Front end optimization for the monolithic active pixel sensor of the ALICE Inner Tracking System upgrade

NASA Astrophysics Data System (ADS)

Kim, D.; Aglieri Rinella, G.; Cavicchioli, C.; Chanlek, N.; Collu, A.; Degerli, Y.; Dorokhov, A.; Flouzat, C.; Gajanana, D.; Gao, C.; Guilloux, F.; Hillemanns, H.; Hristozkov, S.; Junique, A.; Keil, M.; Kofarago, M.; Kugathasan, T.; Kwon, Y.; Lattuca, A.; Mager, M.; Sielewicz, K. M.; Marin Tobon, C. A.; Marras, D.; Martinengo, P.; Mazza, G.; Mugnier, H.; Musa, L.; Pham, T. H.; Puggioni, C.; Reidt, F.; Riedler, P.; Rousset, J.; Siddhanta, S.; Snoeys, W.; Song, M.; Usai, G.; Van Hoorne, J. W.; Yang, P.

2016-02-01

ALICE plans to replace its Inner Tracking System during the second long shut down of the LHC in 2019 with a new 10 m2 tracker constructed entirely with monolithic active pixel sensors. The TowerJazz 180 nm CMOS imaging Sensor process has been selected to produce the sensor as it offers a deep pwell allowing full CMOS in-pixel circuitry and different starting materials. First full-scale prototypes have been fabricated and tested. Radiation tolerance has also been verified. In this paper the development of the charge sensitive front end and in particular its optimization for uniformity of charge threshold and time response will be presented.

Low-power sensor module for long-term activity monitoring.

PubMed

Leuenberger, Kaspar; Gassert, Roger

2011-01-01

Wearable sensor modules are a promising approach to collecting data on functional motor activities, both for repeated and long-term assessments, as well as to investigate the transfer of therapy to activities of daily living at home, but have so far either had limited sensing capabilities, or were not laid out for long-term monitoring. This paper presents ReSense, a miniature sensor unit optimized for long-term monitoring of functional activity. Inertial MEMS sensors capture accelerations along six degrees of freedom and a barometric pressure sensor serves as a precise altimeter. Data is written to an integrated memory card. The realized module measures Ø25 × 10 mm, weighs 10 g and can record continuously for 27 h at 25 Hz and over 22 h at 100 Hz. The integrated power-management system detects inactivity and extends the operating time by about a factor of two, as shown by initial 24 h recordings on five energetic healthy adults. The integrated barometric pressure sensor allowed to identify activities incorporating a change in altitude, such as going up/down stairs or riding an elevator. By taking into account data from the inertial sensors during the altitude changes, it becomes possible to distinguish between these two activities.

Monitoring activities of daily living based on wearable wireless body sensor network.

PubMed

Kańtoch, E; Augustyniak, P; Markiewicz, M; Prusak, D

2014-01-01

With recent advances in microprocessor chip technology, wireless communication, and biomedical engineering it is possible to develop miniaturized ubiquitous health monitoring devices that are capable of recording physiological and movement signals during daily life activities. The aim of the research is to implement and test the prototype of health monitoring system. The system consists of the body central unit with Bluetooth module and wearable sensors: the custom-designed ECG sensor, the temperature sensor, the skin humidity sensor and accelerometers placed on the human body or integrated with clothes and a network gateway to forward data to a remote medical server. The system includes custom-designed transmission protocol and remote web-based graphical user interface for remote real time data analysis. Experimental results for a group of humans who performed various activities (eg. working, running, etc.) showed maximum 5% absolute error compared to certified medical devices. The results are promising and indicate that developed wireless wearable monitoring system faces challenges of multi-sensor human health monitoring during performing daily activities and opens new opportunities in developing novel healthcare services.

Vector disparity sensor with vergence control for active vision systems.

PubMed

Barranco, Francisco; Diaz, Javier; Gibaldi, Agostino; Sabatini, Silvio P; Ros, Eduardo

2012-01-01

This paper presents an architecture for computing vector disparity for active vision systems as used on robotics applications. The control of the vergence angle of a binocular system allows us to efficiently explore dynamic environments, but requires a generalization of the disparity computation with respect to a static camera setup, where the disparity is strictly 1-D after the image rectification. The interaction between vision and motor control allows us to develop an active sensor that achieves high accuracy of the disparity computation around the fixation point, and fast reaction time for the vergence control. In this contribution, we address the development of a real-time architecture for vector disparity computation using an FPGA device. We implement the disparity unit and the control module for vergence, version, and tilt to determine the fixation point. In addition, two on-chip different alternatives for the vector disparity engines are discussed based on the luminance (gradient-based) and phase information of the binocular images. The multiscale versions of these engines are able to estimate the vector disparity up to 32 fps on VGA resolution images with very good accuracy as shown using benchmark sequences with known ground-truth. The performances in terms of frame-rate, resource utilization, and accuracy of the presented approaches are discussed. On the basis of these results, our study indicates that the gradient-based approach leads to the best trade-off choice for the integration with the active vision system.

Vector Disparity Sensor with Vergence Control for Active Vision Systems

PubMed Central

Barranco, Francisco; Diaz, Javier; Gibaldi, Agostino; Sabatini, Silvio P.; Ros, Eduardo

2012-01-01

This paper presents an architecture for computing vector disparity for active vision systems as used on robotics applications. The control of the vergence angle of a binocular system allows us to efficiently explore dynamic environments, but requires a generalization of the disparity computation with respect to a static camera setup, where the disparity is strictly 1-D after the image rectification. The interaction between vision and motor control allows us to develop an active sensor that achieves high accuracy of the disparity computation around the fixation point, and fast reaction time for the vergence control. In this contribution, we address the development of a real-time architecture for vector disparity computation using an FPGA device. We implement the disparity unit and the control module for vergence, version, and tilt to determine the fixation point. In addition, two on-chip different alternatives for the vector disparity engines are discussed based on the luminance (gradient-based) and phase information of the binocular images. The multiscale versions of these engines are able to estimate the vector disparity up to 32 fps on VGA resolution images with very good accuracy as shown using benchmark sequences with known ground-truth. The performances in terms of frame-rate, resource utilization, and accuracy of the presented approaches are discussed. On the basis of these results, our study indicates that the gradient-based approach leads to the best trade-off choice for the integration with the active vision system. PMID:22438737

Experiments on active isolation using distributed PVDF error sensors

NASA Technical Reports Server (NTRS)

Lefebvre, S.; Guigou, C.; Fuller, C. R.

1992-01-01

A control system based on a two-channel narrow-band LMS algorithm is used to isolate periodic vibration at low frequencies on a structure composed of a rigid top plate mounted on a flexible receiving plate. The control performance of distributed PVDF error sensors and accelerometer point sensors is compared. For both sensors, high levels of global reduction, up to 32 dB, have been obtained. It is found that, by driving the PVDF strip output voltage to zero, the controller may force the structure to vibrate so that the integration of the strain under the length of the PVDF strip is zero. This ability of the PVDF sensors to act as spatial filters is especially relevant in active control of sound radiation. It is concluded that the PVDF sensors are flexible, nonfragile, and inexpensive and can be used as strain sensors for active control applications of vibration isolation and sound radiation.

Design of inductive sensors for tongue control system for computers and assistive devices.

PubMed

Lontis, Eugen R; Struijk, Lotte N S A

2010-07-01

The paper introduces a novel design of air-core inductive sensors in printed circuit board (PCB) technology for a tongue control system. The tongue control system provides a quadriplegic person with a keyboard and a joystick type of mouse for interaction with a computer or for control of an assistive device. Activation of inductive sensors was performed with a cylindrical, soft ferromagnetic material (activation unit). Comparative analysis of inductive sensors in PCB technology with existing hand-made inductive sensors was performed with respect to inductance, resistance, and sensitivity to activation when the activation unit was placed in the center of the sensor. Optimisation of the activation unit was performed in a finite element model. PCBs with air-core inductive sensors were manufactured in a 10 layers, 100 microm and 120 microm line width technology. These sensors provided quality signals that could drive the electronics of the hand-made sensors. Furthermore, changing the geometry of the sensors allowed generation of variable signals correlated with the 2D movement of the activation unit at the sensors' surface. PCB technology for inductive sensors allows flexibility in design, automation of production and ease of possible integration with supplying electronics. The basic switch function of the inductive sensor can be extended to two-dimensional movement detection for pointing devices.

Active hydrothermal and non-active massive sulfide mound investigation using a new multiparameter chemical sensor

NASA Astrophysics Data System (ADS)

Han, C.; Wu, G.; Qin, H.; Wang, Z.

2012-12-01

Investigation of active hydrothermal mound as well as non-active massive sulfide mound are studied recently. However, there is still lack of in-situ detection method for the non-active massive sulfide mound. Even though Transient ElectroMagnetic (TEM) and Electric Self-potential (SP) methods are good, they both are labour, time and money cost work. We proposed a new multiparameter chemical sensor method to study the seafloor active hydrothermal mound as well as non-active massive sulfide mound. This sensor integrates Eh, S2- ions concentration and pH electrochemical electrodes together, and could found chemical change caused by the active hydrothermal vent, even weak chemical abnormalities by non-active massive sulfide hydrothermal mound which MARP and CTD sometimes cannot detect. In 2012, the 1st Leg of the Chinese 26th cruise, the multiparameter chemical sensor was carried out with the deepsea camera system over the Carlsberg Ridge in Indian Ocean by R/V DAYANGYIHAO. It was shown small Eh and S2- ions concentration abnormal around a site at Northwest Indian ridge. This site was also evidenced by the TV grab. In the 2nd Leg of the same cruise in June, this chemical sensor was carried out with TEM and SP survey system. The chemical abnormalities are matched very well with both TEM and SP survey results. The results show that the multiparameter chemical sensor method not only can detect active hydrothermal mound, but also can find the non-active massive sulfide hydrothermal mound.

RE-DEFINING THE ROLES OF SENSORS IN OBJECTIVE PHYSICAL ACTIVITY MONITORING

PubMed Central

Chen, Kong Y.; Janz, Kathleen F.; Zhu, Weimo; Brychta, Robert J.

2011-01-01

Background As physical activity researchers are increasingly using objective portable devices, this review describes current state of the technology to assess physical activity, with a focus on specific sensors and sensor properties currently used in monitors and their strengths and weakness. Additional sensors and sensor properties desirable for activity measurement and best practices for users and developers also are discussed. Best Practices We grouped current sensors into three broad categories for objectively measuring physical activity: associated body movement, physiology, and context. Desirable sensor properties for measuring physical activity and the importance of these properties in relationship to specific applications are addressed, and the specific roles of transducers and data acquisition systems within the monitoring devices are defined. Technical advancements in sensors, microcomputer processors, memory storage, batteries, wireless communication, and digital filters have made monitors more usable for subjects (smaller, more stable, and longer running time) and for researchers (less costly, higher time resolution and memory storage, shorter download time, and user-defined data features). Future Directions Users and developers of physical activity monitors should learn about the basic properties of their sensors, such as range, accuracy, precision, while considering the data acquisition/filtering steps that may be critical to data quality and may influence the desirable measurement outcome(s). PMID:22157770

Laser sensor system documentation.

DOT National Transportation Integrated Search

2017-03-01

Phase 1 of TxDOT Project 0-6873, True Road Surface Deflection Measuring Device, developed a : laser sensor system based on several sensors mounted on a rigid beam. : This sensor system remains with CTR currently, as the project is moving into Phase 2...

Active spectral sensor evaluation under varying conditions

USDA-ARS?s Scientific Manuscript database

Plant stress has been estimated by spectral signature using both passive and active sensors. As optical sensors measure reflected light from a target, changes in illumination characteristics critically affect sensor response. Active sensors are of benefit in minimizing uncontrolled illumination effe...

A 128 x 128 CMOS Active Pixel Image Sensor for Highly Integrated Imaging Systems

NASA Technical Reports Server (NTRS)

Mendis, Sunetra K.; Kemeny, Sabrina E.; Fossum, Eric R.

1993-01-01

A new CMOS-based image sensor that is intrinsically compatible with on-chip CMOS circuitry is reported. The new CMOS active pixel image sensor achieves low noise, high sensitivity, X-Y addressability, and has simple timing requirements. The image sensor was fabricated using a 2 micrometer p-well CMOS process, and consists of a 128 x 128 array of 40 micrometer x 40 micrometer pixels. The CMOS image sensor technology enables highly integrated smart image sensors, and makes the design, incorporation and fabrication of such sensors widely accessible to the integrated circuit community.

A novel design of an automatic lighting control system for a wireless sensor network with increased sensor lifetime and reduced sensor numbers.

PubMed

Mohamaddoust, Reza; Haghighat, Abolfazl Toroghi; Sharif, Mohamad Javad Motahari; Capanni, Niccolo

2011-01-01

Wireless sensor networks (WSN) are currently being applied to energy conservation applications such as light control. We propose a design for such a system called a lighting automatic control system (LACS). The LACS system contains a centralized or distributed architecture determined by application requirements and space usage. The system optimizes the calculations and communications for lighting intensity, incorporates user illumination requirements according to their activities and performs adjustments based on external lighting effects in external sensor and external sensor-less architectures. Methods are proposed for reducing the number of sensors required and increasing the lifetime of those used, for considerably reduced energy consumption. Additionally we suggest methods for improving uniformity of illuminance distribution on a workplane's surface, which improves user satisfaction. Finally simulation results are presented to verify the effectiveness of our design.

Energy Systems Sensor Laboratory | Energy Systems Integration Facility |

Science.gov Websites

NREL Sensor Laboratory Energy Systems Sensor Laboratory The Energy Systems Integration Facility's Energy Systems Sensor Laboratory is designed to support research, development, testing, and evaluation of advanced hydrogen sensor technologies to support the needs of the emerging hydrogen

Active Targets For Capacitive Proximity Sensors

NASA Technical Reports Server (NTRS)

Jenstrom, Del T.; Mcconnell, Robert L.

1994-01-01

Lightweight, low-power active targets devised for use with improved capacitive proximity sensors described in "Capacitive Proximity Sensor Has Longer Range" (GSC-13377), and "Capacitive Proximity Sensors With Additional Driven Shields" (GSC-13475). Active targets are short-distance electrostatic beacons; they generate known alternating electro-static fields used for alignment and/or to measure distances.

Microfluidic electrochemical sensor for on-line monitoring of aerosol oxidative activity.

PubMed

Sameenoi, Yupaporn; Koehler, Kirsten; Shapiro, Jeff; Boonsong, Kanokporn; Sun, Yele; Collett, Jeffrey; Volckens, John; Henry, Charles S

2012-06-27

Particulate matter (PM) air pollution has a significant impact on human morbidity and mortality; however, the mechanisms of PM-induced toxicity are poorly defined. A leading hypothesis states that airborne PM induces harm by generating reactive oxygen species in and around human tissues, leading to oxidative stress. We report here a system employing a microfluidic electrochemical sensor coupled directly to a particle-into-liquid sampler (PILS) system to measure aerosol oxidative activity in an on-line format. The oxidative activity measurement is based on the dithiothreitol (DTT) assay, where, after being oxidized by PM, the remaining reduced DTT is analyzed by the microfluidic sensor. The sensor consists of an array of working, reference, and auxiliary electrodes fabricated in a poly(dimethylsiloxane)-based microfluidic device. Cobalt(II) phthalocyanine-modified carbon paste was used as the working electrode material, allowing selective detection of reduced DTT. The electrochemical sensor was validated off-line against the traditional DTT assay using filter samples taken from urban environments and biomass burning events. After off-line characterization, the sensor was coupled to a PILS to enable on-line sampling/analysis of aerosol oxidative activity. Urban dust and industrial incinerator ash samples were aerosolized in an aerosol chamber and analyzed for their oxidative activity. The on-line sensor reported DTT consumption rates (oxidative activity) in good correlation with aerosol concentration (R(2) from 0.86 to 0.97) with a time resolution of approximately 3 min.

A Wireless Self-Powered Urinary Incontinence Sensor System

NASA Astrophysics Data System (ADS)

Tanaka, Ami; Utsunomiya, Fumiyasu; Douseki, Takakuni

A self-powered urinary incontinence sensor system consisting of a urine-activated coin battery and a wireless transmitter has been developed as an application for wireless biosensor networks. The urine-activated battery makes possible both the sensing of urine leakage and self-powered operation. An intermittent power-supply circuit that uses an electric double-layer capacitor (EDLC) with a small internal resistance suppresses the supply voltage drop due to the large internal resistance of the battery. This circuit and a 1-V surface acoustic wave (SAW) oscillator reduce the power dissipation of a wireless transmitter. The SAW oscillator quickly responds to the on-off control of the power supply, which is suitable for intermittent operation. To verify the effectiveness of the circuit scheme, the authors fabricated a prototype sensor system. When the volume of urine is 0.2 ml, the battery outputs a voltage of over 1.3 V; and the sensor system can transmit signals over a distance of 5 m.

2D-Visualization of metabolic activity with planar optical chemical sensors (optodes)

NASA Astrophysics Data System (ADS)

Meier, R. J.; Liebsch, G.

2015-12-01

Microbia plays an outstandingly important role in many hydrologic compartments, such as e.g. the benthic community in sediments, or biologically active microorganisms in the capillary fringe, in ground water, or soil. Oxygen, pH, and CO2 are key factors and indicators for microbial activity. They can be measured using optical chemical sensors. These sensors record changing fluorescence properties of specific indicator dyes. The signals can be measured in a non-contact mode, even through transparent walls, which is important for many lab-experiments. They can measure in closed (transparent) systems, without sampling or intruding into the sample. They do not consume the analytes while measuring, are fully reversible and able to measure in non-stirred solutions. These sensors can be applied as high precision fiberoptic sensors (for profiling), robust sensor spots, or as planar sensors for 2D visualization (imaging). Imaging enables to detect thousands of measurement spots at the same time and generate 2D analyte maps over a region of interest. It allows for comparing different regions within one recorded image, visualizing spatial analyte gradients, or more important to identify hot spots of metabolic activity. We present ready-to-use portable imaging systems for the analytes oxygen, pH, and CO2. They consist of a detector unit, planar sensor foils and a software for easy data recording and evaluation. Sensors foils for various analytes and measurement ranges enable visualizing metabolic activity or analyte changes in the desired range. Dynamics of metabolic activity can be detected in one shot or over long time periods. We demonstrate the potential of this analytical technique by presenting experiments on benthic disturbance-recovery dynamics in sediments and microbial degradation of organic material in the capillary fringe. We think this technique is a new tool to further understand how microbial and geochemical processes are linked in (not solely) hydrologic

Virtual sensors for active noise control in acoustic-structural coupled enclosures using structural sensing: robust virtual sensor design.

PubMed

Halim, Dunant; Cheng, Li; Su, Zhongqing

2011-03-01

The work was aimed to develop a robust virtual sensing design methodology for sensing and active control applications of vibro-acoustic systems. The proposed virtual sensor was designed to estimate a broadband acoustic interior sound pressure using structural sensors, with robustness against certain dynamic uncertainties occurring in an acoustic-structural coupled enclosure. A convex combination of Kalman sub-filters was used during the design, accommodating different sets of perturbed dynamic model of the vibro-acoustic enclosure. A minimax optimization problem was set up to determine an optimal convex combination of Kalman sub-filters, ensuring an optimal worst-case virtual sensing performance. The virtual sensing and active noise control performance was numerically investigated on a rectangular panel-cavity system. It was demonstrated that the proposed virtual sensor could accurately estimate the interior sound pressure, particularly the one dominated by cavity-controlled modes, by using a structural sensor. With such a virtual sensing technique, effective active noise control performance was also obtained even for the worst-case dynamics. © 2011 Acoustical Society of America

ESAM: Endocrine inspired Sensor Activation Mechanism for multi-target tracking in WSNs

NASA Astrophysics Data System (ADS)

Adil Mahdi, Omar; Wahab, Ainuddin Wahid Abdul; Idris, Mohd Yamani Idna; Znaid, Ammar Abu; Khan, Suleman; Al-Mayouf, Yusor Rafid Bahar

2016-10-01

Target tracking is a significant application of wireless sensor networks (WSNs) in which deployment of self-organizing and energy efficient algorithms is required. The tracking accuracy increases as more sensor nodes are activated around the target but more energy is consumed. Thus, in this study, we focus on limiting the number of sensors by forming an ad-hoc network that operates autonomously. This will reduce the energy consumption and prolong the sensor network lifetime. In this paper, we propose a fully distributed algorithm, an Endocrine inspired Sensor Activation Mechanism for multi target-tracking (ESAM) which reflecting the properties of real life sensor activation system based on the information circulating principle in the endocrine system of the human body. Sensor nodes in our network are secreting different hormones according to certain rules. The hormone level enables the nodes to regulate an efficient sleep and wake up cycle of nodes to reduce the energy consumption. It is evident from the simulation results that the proposed ESAM in autonomous sensor network exhibits a stable performance without the need of commands from a central controller. Moreover, the proposed ESAM generates more efficient and persistent results as compared to other algorithms for tracking an invading object.

Sensor Failure Detection of FASSIP System using Principal Component Analysis

NASA Astrophysics Data System (ADS)

Sudarno; Juarsa, Mulya; Santosa, Kussigit; Deswandri; Sunaryo, Geni Rina

2018-02-01

In the nuclear reactor accident of Fukushima Daiichi in Japan, the damages of core and pressure vessel were caused by the failure of its active cooling system (diesel generator was inundated by tsunami). Thus researches on passive cooling system for Nuclear Power Plant are performed to improve the safety aspects of nuclear reactors. The FASSIP system (Passive System Simulation Facility) is an installation used to study the characteristics of passive cooling systems at nuclear power plants. The accuracy of sensor measurement of FASSIP system is essential, because as the basis for determining the characteristics of a passive cooling system. In this research, a sensor failure detection method for FASSIP system is developed, so the indication of sensor failures can be detected early. The method used is Principal Component Analysis (PCA) to reduce the dimension of the sensor, with the Squarred Prediction Error (SPE) and statistic Hotteling criteria for detecting sensor failure indication. The results shows that PCA method is capable to detect the occurrence of a failure at any sensor.

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.

Active Low Intrusion Hybrid Monitor for Wireless Sensor Networks

PubMed Central

Navia, Marlon; Campelo, Jose C.; Bonastre, Alberto; Ors, Rafael; Capella, Juan V.; Serrano, Juan J.

2015-01-01

Several systems have been proposed to monitor wireless sensor networks (WSN). These systems may be active (causing a high degree of intrusion) or passive (low observability inside the nodes). This paper presents the implementation of an active hybrid (hardware and software) monitor with low intrusion. It is based on the addition to the sensor node of a monitor node (hardware part) which, through a standard interface, is able to receive the monitoring information sent by a piece of software executed in the sensor node. The intrusion on time, code, and energy caused in the sensor nodes by the monitor is evaluated as a function of data size and the interface used. Then different interfaces, commonly available in sensor nodes, are evaluated: serial transmission (USART), serial peripheral interface (SPI), and parallel. The proposed hybrid monitor provides highly detailed information, barely disturbed by the measurement tool (interference), about the behavior of the WSN that may be used to evaluate many properties such as performance, dependability, security, etc. Monitor nodes are self-powered and may be removed after the monitoring campaign to be reused in other campaigns and/or WSNs. No other hardware-independent monitoring platforms with such low interference have been found in the literature. PMID:26393604

Sensor web enables rapid response to volcanic activity

USGS Publications Warehouse

Davies, Ashley G.; Chien, Steve; Wright, Robert; Miklius, Asta; Kyle, Philip R.; Welsh, Matt; Johnson, Jeffrey B.; Tran, Daniel; Schaffer, Steven R.; Sherwood, Robert

2006-01-01

Rapid response to the onset of volcanic activity allows for the early assessment of hazard and risk [Tilling, 1989]. Data from remote volcanoes and volcanoes in countries with poor communication infrastructure can only be obtained via remote sensing [Harris et al., 2000]. By linking notifications of activity from ground-based and spacebased systems, these volcanoes can be monitored when they erupt.Over the last 18 months, NASA's Jet Propulsion Laboratory (JPL) has implemented a Volcano Sensor Web (VSW) in which data from ground-based and space-based sensors that detect current volcanic activity are used to automatically trigger the NASA Earth Observing 1 (EO-1) spacecraft to make highspatial-resolution observations of these volcanoes.

Peptide-based Fluorescent Sensors of Protein Kinase Activity: Design and Applications

PubMed Central

Sharma, Vyas; Wang, Qunzhao; Lawrence, David S.

2009-01-01

Protein kinases control the flow of information through cell-signaling pathways. A detailed analysis of their behavior enhances our ability to understand normal cellular states and to devise therapeutic interventions for diseases. The design and application of “Environmentally-Sensitive”, “Deep-Quench” and “Self-Reporting” sensor systems for studying protein kinase activity are described. These sensors allow real-time activity measurements in a continuous manner for a wide variety of kinases. As these sensors can be adapted from an in vitro screen to imaging kinase activity in living cells, they support both preliminary and later stages of drug discovery. PMID:17881302

A Novel Design of an Automatic Lighting Control System for a Wireless Sensor Network with Increased Sensor Lifetime and Reduced Sensor Numbers

PubMed Central

Mohamaddoust, Reza; Haghighat, Abolfazl Toroghi; Sharif, Mohamad Javad Motahari; Capanni, Niccolo

2011-01-01

Wireless sensor networks (WSN) are currently being applied to energy conservation applications such as light control. We propose a design for such a system called a Lighting Automatic Control System (LACS). The LACS system contains a centralized or distributed architecture determined by application requirements and space usage. The system optimizes the calculations and communications for lighting intensity, incorporates user illumination requirements according to their activities and performs adjustments based on external lighting effects in external sensor and external sensor-less architectures. Methods are proposed for reducing the number of sensors required and increasing the lifetime of those used, for considerably reduced energy consumption. Additionally we suggest methods for improving uniformity of illuminance distribution on a workplane’s surface, which improves user satisfaction. Finally simulation results are presented to verify the effectiveness of our design. PMID:22164114

Sensor Network Infrastructure for a Home Care Monitoring System

PubMed Central

Palumbo, Filippo; Ullberg, Jonas; Štimec, Ales; Furfari, Francesco; Karlsson, Lars; Coradeschi, Silvia

2014-01-01

This paper presents the sensor network infrastructure for a home care system that allows long-term monitoring of physiological data and everyday activities. The aim of the proposed system is to allow the elderly to live longer in their home without compromising safety and ensuring the detection of health problems. The system offers the possibility of a virtual visit via a teleoperated robot. During the visit, physiological data and activities occurring during a period of time can be discussed. These data are collected from physiological sensors (e.g., temperature, blood pressure, glucose) and environmental sensors (e.g., motion, bed/chair occupancy, electrical usage). The system can also give alarms if sudden problems occur, like a fall, and warnings based on more long-term trends, such as the deterioration of health being detected. It has been implemented and tested in a test environment and has been deployed in six real homes for a year-long evaluation. The key contribution of the paper is the presentation of an implemented system for ambient assisted living (AAL) tested in a real environment, combining the acquisition of sensor data, a flexible and adaptable middleware compliant with the OSGistandard and a context recognition application. The system has been developed in a European project called GiraffPlus. PMID:24573309

Sensor network infrastructure for a home care monitoring system.

PubMed

Palumbo, Filippo; Ullberg, Jonas; Stimec, Ales; Furfari, Francesco; Karlsson, Lars; Coradeschi, Silvia

2014-02-25

This paper presents the sensor network infrastructure for a home care system that allows long-term monitoring of physiological data and everyday activities. The aim of the proposed system is to allow the elderly to live longer in their home without compromising safety and ensuring the detection of health problems. The system offers the possibility of a virtual visit via a teleoperated robot. During the visit, physiological data and activities occurring during a period of time can be discussed. These data are collected from physiological sensors (e.g., temperature, blood pressure, glucose) and environmental sensors (e.g., motion, bed/chair occupancy, electrical usage). The system can also give alarms if sudden problems occur, like a fall, and warnings based on more long-term trends, such as the deterioration of health being detected. It has been implemented and tested in a test environment and has been deployed in six real homes for a year-long evaluation. The key contribution of the paper is the presentation of an implemented system for ambient assisted living (AAL) tested in a real environment, combining the acquisition of sensor data, a flexible and adaptable middleware compliant with the OSGistandard and a context recognition application. The system has been developed in a European project called GiraffPlus.

A novel bicistronic sensor vector for detecting caspase-3 activation.

PubMed

Vagner, Tatyana; Mouravlev, Alexandre; Young, Deborah

2015-01-01

Apoptosis is involved in pathological cell death of a wide range of human diseases. One of the most important biochemical markers of apoptosis is activation of caspase-3. Ability to detect caspase-3 activation early in the pathological process is important for determining the timing for interfering with apoptosis initiation and prevention of cell damage. Techniques allowing detection of caspase-3 activity at a single cell level show increased sensitivity, compared to biochemical assays; therefore, we developed a novel bicistronic caspase-3 sensor vector enabling detection of caspase-3 activity in individual cells. We employed green fluorescent protein (GFP) as a reporter for caspase-3 activation in our constructs and assessed the functionality of the generated constructs in transiently transfected Neuro2A and HEK293 cells under basal conditions and following application of okadaic acid (OA) or staurosporine (STS) to induce apoptosis. To ensure responsiveness of the new sensor vector to active caspase-3, we co-transfected the sensor with plasmid(s) overexpressing active caspase-3 and quantified GFP fluorescence using a plate reader. We observed an increase in GFP expression in cells transfected with the new bicistronic caspase-3 sensor in response to both OA and STS. We also showed a significant increase in GFP fluorescence intensity in cells co-expressing the sensor with the plasmid(s) encoding active caspase-3. We generated a novel bicistronic caspase-3 sensor vector which relies on a transcription factor/response element system. The obtained sensor combines high sensitivity of the single cell level detection with the possibility of automated quantification. Copyright © 2015 Elsevier Inc. All rights reserved.

Chemical Sensor Platform for Non-Invasive Monitoring of Activity and Dehydration

PubMed Central

Solovei, Dmitry; Žák, Jaromír; Majzlíková, Petra; Sedláček, Jiří; Hubálek, Jaromír

2015-01-01

A non-invasive solution for monitoring of the activity and dehydration of organisms is proposed in the work. For this purpose, a wireless standalone chemical sensor platform using two separate measurement techniques has been developed. The first approach for activity monitoring is based on humidity measurement. Our solution uses new humidity sensor based on a nanostructured TiO2 surface for sweat rate monitoring. The second technique is based on monitoring of potassium concentration in urine. High level of potassium concentration denotes clear occurrence of dehydration. Furthermore, a Wireless Body Area Network (WBAN) was developed for this sensor platform to manage data transfer among devices and the internet. The WBAN coordinator controls the sensor devices and collects and stores the measured data. The collected data is particular to individuals and can be shared with physicians, emergency systems or athletes' coaches. Long-time monitoring of activity and potassium concentration in urine can help maintain the appropriate water intake of elderly people or athletes and to send warning signals in the case of near dehydration. The created sensor system was calibrated and tested in laboratory and real conditions as well. The measurement results are discussed. PMID:25594591

Wearable sensor glove based on conducting fabric using electrodermal activity and pulse-wave sensors for e-health application.

PubMed

Lee, Youngbum; Lee, Byungwoo; Lee, Myoungho

2010-03-01

Improvement of the quality and efficiency of health in medicine, both at home and the hospital, calls for improved sensors that might be included in a common carrier such as a wearable sensor device to measure various biosignals and provide healthcare services that use e-health technology. Designed to be user-friendly, smart clothes and gloves respond well to the end users for health monitoring. This study describes a wearable sensor glove that is equipped with an electrodermal activity (EDA) sensor, pulse-wave sensor, conducting fabric, and an embedded system. The EDA sensor utilizes the relationship between drowsiness and the EDA signal. The EDA sensors were made using a conducting fabric instead of silver chloride electrodes, as a more practical and practically wearable device. The pulse-wave sensor measurement system, which is widely applied in oriental medicinal practices, is also a strong element in e-health monitoring systems. The EDA and pulse-wave signal acquisition module was constructed by connecting the sensor to the glove via a conductive fabric. The signal acquisition module is then connected to a personal computer that displays the results of the EDA and pulse-wave signal processing analysis and gives accurate feedback to the user. This system is designed for a number of applications for the e-health services, including drowsiness detection and oriental medicine.

Bio-integrated electronics and sensor systems

NASA Astrophysics Data System (ADS)

Yeo, Woon-Hong; Webb, R. Chad; Lee, Woosik; Jung, Sungyoung; Rogers, John A.

2013-05-01

Skin-mounted epidermal electronics, a strategy for bio-integrated electronics, provide an avenue to non-invasive monitoring of clinically relevant physiological signals for healthcare applications. Current conventional systems consist of single-point sensors fastened to the skin with adhesives, and sometimes with conducting gels, which limits their use outside of clinical settings due to loss of adhesion and irritation to the user. In order to facilitate extended use of skin-mounted healthcare sensors without disrupting everyday life, we envision electronic monitoring systems that integrate seamlessly with the skin below the notice of the user. This manuscript reviews recent significant results towards our goal of wearable electronic sensor systems for long-term monitoring of physiological signals. Ultra-thin epidermal electronic systems (EES) are demonstrated for extended use on the skin, in a conformal manner, including during everyday bathing and sleeping activities. We describe the assessment of clinically relevant physiological parameters, such as electrocardiograms (ECG), electromyograms (EMG), electroencephalograms (EEG), temperature, mechanical strain and thermal conductivity, using examples of multifunctional EES devices. Additionally, we demonstrate capability for real life application of EES by monitoring the system functionality, which has no discernible change, during cyclic fatigue testing.

An Embedded Multi-Agent Systems Based Industrial Wireless Sensor Network.

PubMed

Taboun, Mohammed S; Brennan, Robert W

2017-09-14

With the emergence of cyber-physical systems, there has been a growing interest in network-connected devices. One of the key requirements of a cyber-physical device is the ability to sense its environment. Wireless sensor networks are a widely-accepted solution for this requirement. In this study, an embedded multi-agent systems-managed wireless sensor network is presented. A novel architecture is proposed, along with a novel wireless sensor network architecture. Active and passive wireless sensor node types are defined, along with their communication protocols, and two application-specific examples are presented. A series of three experiments is conducted to evaluate the performance of the agent-embedded wireless sensor network.

Toward real time detection of the basic living activity in home using a wearable sensor and smart home sensors.

PubMed

Bang, Sunlee; Kim, Minho; Song, Sa-Kwang; Park, Soo-Jun

2008-01-01

As the elderly people living alone are enormously increasing recently, we need the system inferring activities of daily living (ADL) for maintaining healthy life and recognizing emergency. The system should be constructed with sensors, which are used to associate with people's living while remaining as non intrusive views as possible. To do this, the proposed system use a triaxial accelerometer sensor and environment sensors indicating contact with subject in home. Particularly, in order to robustly infer ADLs, we present component ADL, which is decided with conjunction of human motion together, not just only contacted object identification. It is an important component in inferring ADL. In special, component ADL decision firstly refines misclassified initial activities, which improves the accuracy of recognizing ADL. Preliminary experiments results for proposed system provides overall recognition rate of over 97% over 8 component ADLs, which can be effectively applicable to recognize the final ADLs.

Wearable sensor systems for infants.

PubMed

Zhu, Zhihua; Liu, Tao; Li, Guangyi; Li, Tong; Inoue, Yoshio

2015-02-05

Continuous health status monitoring of infants is achieved with the development and fusion of wearable sensing technologies, wireless communication techniques and a low energy-consumption microprocessor with high performance data processing algorithms. As a clinical tool applied in the constant monitoring of physiological parameters of infants, wearable sensor systems for infants are able to transmit the information obtained inside an infant's body to clinicians or parents. Moreover, such systems with integrated sensors can perceive external threats such as falling or drowning and warn parents immediately. Firstly, the paper reviews some available wearable sensor systems for infants; secondly, we introduce the different modules of the framework in the sensor systems; lastly, the methods and techniques applied in the wearable sensor systems are summarized and discussed. The latest research and achievements have been highlighted in this paper and the meaningful applications in healthcare and behavior analysis are also presented. Moreover, we give a lucid perspective of the development of wearable sensor systems for infants in the future.

Wearable Sensor Systems for Infants

PubMed Central

Zhu, Zhihua; Liu, Tao; Li, Guangyi; Li, Tong; Inoue, Yoshio

2015-01-01

Continuous health status monitoring of infants is achieved with the development and fusion of wearable sensing technologies, wireless communication techniques and a low energy-consumption microprocessor with high performance data processing algorithms. As a clinical tool applied in the constant monitoring of physiological parameters of infants, wearable sensor systems for infants are able to transmit the information obtained inside an infant's body to clinicians or parents. Moreover, such systems with integrated sensors can perceive external threats such as falling or drowning and warn parents immediately. Firstly, the paper reviews some available wearable sensor systems for infants; secondly, we introduce the different modules of the framework in the sensor systems; lastly, the methods and techniques applied in the wearable sensor systems are summarized and discussed. The latest research and achievements have been highlighted in this paper and the meaningful applications in healthcare and behavior analysis are also presented. Moreover, we give a lucid perspective of the development of wearable sensor systems for infants in the future. PMID:25664432

Soldier systems sensor fusion

NASA Astrophysics Data System (ADS)

Brubaker, Kathryne M.

1998-08-01

This paper addresses sensor fusion and its applications in emerging Soldier Systems integration and the unique challenges associated with the human platform. Technology that,provides the highest operational payoff in a lightweight warrior system must not only have enhanced capabilities, but have low power components resulting in order of magnitude reductions coupled with significant cost reductions. These reductions in power and cost will be achieved through partnership with industry and leveraging of commercial state of the art advancements in microelectronics and power sources. As new generation of full solution fire control systems (to include temperature, wind and range sensors) and target acquisition systems will accompany a new generation of individual combat weapons and upgrade existing weapon systems. Advanced lightweight thermal, IR, laser and video senors will be used for surveillance, target acquisition, imaging and combat identification applications. Multifunctional sensors will provide embedded training features in combat configurations allowing the soldier to 'train as he fights' without the traditional cost and weight penalties associated with separate systems. Personal status monitors (detecting pulse, respiration rate, muscle fatigue, core temperature, etc.) will provide commanders and highest echelons instantaneous medical data. Seamless integration of GPS and dead reckoning (compass and pedometer) and/or inertial sensors will aid navigation and increase position accuracy. Improved sensors and processing capability will provide earlier detection of battlefield hazards such as mines, enemy lasers and NBC (nuclear, biological, chemical) agents. Via the digitized network the situational awareness database will automatically be updated with weapon, medical, position and battlefield hazard data. Soldier Systems Sensor Fusion will ultimately establish each individual soldier as an individual sensor on the battlefield.

Sensitivity-Enhanced Wearable Active Voiceprint Sensor Based on Cellular Polypropylene Piezoelectret.

PubMed

Li, Wenbo; Zhao, Sheng; Wu, Nan; Zhong, Junwen; Wang, Bo; Lin, Shizhe; Chen, Shuwen; Yuan, Fang; Jiang, Hulin; Xiao, Yongjun; Hu, Bin; Zhou, Jun

2017-07-19

Wearable active sensors have extensive applications in mobile biosensing and human-machine interaction but require good flexibility, high sensitivity, excellent stability, and self-powered feature. In this work, cellular polypropylene (PP) piezoelectret was chosen as the core material of a sensitivity-enhanced wearable active voiceprint sensor (SWAVS) to realize voiceprint recognition. By virtue of the dipole orientation control method, the air layers in the piezoelectret were efficiently utilized, and the current sensitivity was enhanced (from 1.98 pA/Hz to 5.81 pA/Hz at 115 dB). The SWAVS exhibited the superiorities of high sensitivity, accurate frequency response, and excellent stability. The voiceprint recognition system could make correct reactions to human voices by judging both the password and speaker. This study presented a voiceprint sensor with potential applications in noncontact biometric recognition and safety guarantee systems, promoting the progress of wearable sensor networks.

Characteristics of active spectral sensor for plant sensing

USDA-ARS?s Scientific Manuscript database

Plant stress has been estimated by spectral signature using both passive and active sensors. As optical sensors measure reflected light from a target, changes in illumination conditions critically affect sensor response. Active spectral sensors minimize the illumination effects by producing their ...

Performance Evaluation of State of the Art Systems for Physical Activity Classification of Older Subjects Using Inertial Sensors in a Real Life Scenario: A Benchmark Study

PubMed Central

Awais, Muhammad; Palmerini, Luca; Bourke, Alan K.; Ihlen, Espen A. F.; Helbostad, Jorunn L.; Chiari, Lorenzo

2016-01-01

The popularity of using wearable inertial sensors for physical activity classification has dramatically increased in the last decade due to their versatility, low form factor, and low power requirements. Consequently, various systems have been developed to automatically classify daily life activities. However, the scope and implementation of such systems is limited to laboratory-based investigations. Furthermore, these systems are not directly comparable, due to the large diversity in their design (e.g., number of sensors, placement of sensors, data collection environments, data processing techniques, features set, classifiers, cross-validation methods). Hence, the aim of this study is to propose a fair and unbiased benchmark for the field-based validation of three existing systems, highlighting the gap between laboratory and real-life conditions. For this purpose, three representative state-of-the-art systems are chosen and implemented to classify the physical activities of twenty older subjects (76.4 ± 5.6 years). The performance in classifying four basic activities of daily life (sitting, standing, walking, and lying) is analyzed in controlled and free living conditions. To observe the performance of laboratory-based systems in field-based conditions, we trained the activity classification systems using data recorded in a laboratory environment and tested them in real-life conditions in the field. The findings show that the performance of all systems trained with data in the laboratory setting highly deteriorates when tested in real-life conditions, thus highlighting the need to train and test the classification systems in the real-life setting. Moreover, we tested the sensitivity of chosen systems to window size (from 1 s to 10 s) suggesting that overall accuracy decreases with increasing window size. Finally, to evaluate the impact of the number of sensors on the performance, chosen systems are modified considering only the sensing unit worn at the lower back

An Embedded Multi-Agent Systems Based Industrial Wireless Sensor Network

PubMed Central

Brennan, Robert W.

2017-01-01

With the emergence of cyber-physical systems, there has been a growing interest in network-connected devices. One of the key requirements of a cyber-physical device is the ability to sense its environment. Wireless sensor networks are a widely-accepted solution for this requirement. In this study, an embedded multi-agent systems-managed wireless sensor network is presented. A novel architecture is proposed, along with a novel wireless sensor network architecture. Active and passive wireless sensor node types are defined, along with their communication protocols, and two application-specific examples are presented. A series of three experiments is conducted to evaluate the performance of the agent-embedded wireless sensor network. PMID:28906452

Virtual sensors for active noise control in acoustic-structural coupled enclosures using structural sensing: part II--Optimization of structural sensor placement.

PubMed

Halim, Dunant; Cheng, Li; Su, Zhongqing

2011-04-01

The work proposed an optimization approach for structural sensor placement to improve the performance of vibro-acoustic virtual sensor for active noise control applications. The vibro-acoustic virtual sensor was designed to estimate the interior sound pressure of an acoustic-structural coupled enclosure using structural sensors. A spectral-spatial performance metric was proposed, which was used to quantify the averaged structural sensor output energy of a vibro-acoustic system excited by a spatially varying point source. It was shown that (i) the overall virtual sensing error energy was contributed additively by the modal virtual sensing error and the measurement noise energy; (ii) each of the modal virtual sensing error system was contributed by both the modal observability levels for the structural sensing and the target acoustic virtual sensing; and further (iii) the strength of each modal observability level was influenced by the modal coupling and resonance frequencies of the associated uncoupled structural/cavity modes. An optimal design of structural sensor placement was proposed to achieve sufficiently high modal observability levels for certain important panel- and cavity-controlled modes. Numerical analysis on a panel-cavity system demonstrated the importance of structural sensor placement on virtual sensing and active noise control performance, particularly for cavity-controlled modes.

Compact, self-contained enhanced-vision system (EVS) sensor simulator

NASA Astrophysics Data System (ADS)

Tiana, Carlo

2007-04-01

We describe the model SIM-100 PC-based simulator, for imaging sensors used, or planned for use, in Enhanced Vision System (EVS) applications. Typically housed in a small-form-factor PC, it can be easily integrated into existing out-the-window visual simulators for fixed-wing or rotorcraft, to add realistic sensor imagery to the simulator cockpit. Multiple bands of infrared (short-wave, midwave, extended-midwave and longwave) as well as active millimeter-wave RADAR systems can all be simulated in real time. Various aspects of physical and electronic image formation and processing in the sensor are accurately (and optionally) simulated, including sensor random and fixed pattern noise, dead pixels, blooming, B-C scope transformation (MMWR). The effects of various obscurants (fog, rain, etc.) on the sensor imagery are faithfully represented and can be selected by an operator remotely and in real-time. The images generated by the system are ideally suited for many applications, ranging from sensor development engineering tradeoffs (Field Of View, resolution, etc.), to pilot familiarization and operational training, and certification support. The realistic appearance of the simulated images goes well beyond that of currently deployed systems, and beyond that required by certification authorities; this level of realism will become necessary as operational experience with EVS systems grows.

A multi-agent system architecture for sensor networks.

PubMed

Fuentes-Fernández, Rubén; Guijarro, María; Pajares, Gonzalo

2009-01-01

The design of the control systems for sensor networks presents important challenges. Besides the traditional problems about how to process the sensor data to obtain the target information, engineers need to consider additional aspects such as the heterogeneity and high number of sensors, and the flexibility of these networks regarding topologies and the sensors in them. Although there are partial approaches for resolving these issues, their integration relies on ad hoc solutions requiring important development efforts. In order to provide an effective approach for this integration, this paper proposes an architecture based on the multi-agent system paradigm with a clear separation of concerns. The architecture considers sensors as devices used by an upper layer of manager agents. These agents are able to communicate and negotiate services to achieve the required functionality. Activities are organized according to roles related with the different aspects to integrate, mainly sensor management, data processing, communication and adaptation to changes in the available devices and their capabilities. This organization largely isolates and decouples the data management from the changing network, while encouraging reuse of solutions. The use of the architecture is facilitated by a specific modelling language developed through metamodelling. A case study concerning a generic distributed system for fire fighting illustrates the approach and the comparison with related work.

A Novel Wearable Sensor-Based Human Activity Recognition Approach Using Artificial Hydrocarbon Networks.

PubMed

Ponce, Hiram; Martínez-Villaseñor, María de Lourdes; Miralles-Pechuán, Luis

2016-07-05

Human activity recognition has gained more interest in several research communities given that understanding user activities and behavior helps to deliver proactive and personalized services. There are many examples of health systems improved by human activity recognition. Nevertheless, the human activity recognition classification process is not an easy task. Different types of noise in wearable sensors data frequently hamper the human activity recognition classification process. In order to develop a successful activity recognition system, it is necessary to use stable and robust machine learning techniques capable of dealing with noisy data. In this paper, we presented the artificial hydrocarbon networks (AHN) technique to the human activity recognition community. Our artificial hydrocarbon networks novel approach is suitable for physical activity recognition, noise tolerance of corrupted data sensors and robust in terms of different issues on data sensors. We proved that the AHN classifier is very competitive for physical activity recognition and is very robust in comparison with other well-known machine learning methods.

Evaluation and Improvement of Eddy Current Position Sensors in Magnetically Suspended Flywheel Systems

NASA Technical Reports Server (NTRS)

Dever, Timothy P.; Palazzolo, Alan B.; Thomas, Erwin M., III; Jansen, Ralph H.; McLallin, Kerry (Technical Monitor); Soeder, James (Technical Monitor)

2001-01-01

Eddy current position sensor performance is evaluated for use in a high-speed flywheel development system. The flywheel utilizes a five axis active magnetic bearing system. The eddy current sensors are used for position feedback for the bearing controller. Measured characteristics include sensitivity to multiple target materials and susceptibility to noise from the magnetic bearings and from sensor-to-sensor crosstalk. Improvements in axial sensor configuration and techniques for noise reduction are described.

Monolithic active pixel sensor development for the upgrade of the ALICE inner tracking system

NASA Astrophysics Data System (ADS)

Aglieri, G.; Cavicchioli, C.; Chalmet, P. L.; Chanlek, N.; Collu, A.; Giubilato, P.; Hillemanns, H.; Junique, A.; Keil, M.; Kim, D.; Kim, J.; Kugathasan, T.; Lattuca, A.; Mager, M.; Marin Tobon, C. A.; Marras, D.; Martinengo, P.; Mattiazzo, S.; Mazza, G.; Mugnier, H.; Musa, L.; Pantano, D.; Puggioni, C.; Rousset, J.; Reidt, F.; Riedler, P.; Siddhanta, S.; Snoeys, W.; Usai, G.; van Hoorne, J. W.; Yang, P.; Yi, J.

2013-12-01

ALICE plans an upgrade of its Inner Tracking System for 2018. The development of a monolithic active pixel sensor for this upgrade is described. The TowerJazz 180 nm CMOS imaging sensor process has been chosen as it is possible to use full CMOS in the pixel due to the offering of a deep pwell and also to use different starting materials. The ALPIDE development is an alternative to approaches based on a rolling shutter architecture, and aims to reduce power consumption and integration time by an order of magnitude below the ALICE specifications, which would be quite beneficial in terms of material budget and background. The approach is based on an in-pixel binary front-end combined with a hit-driven architecture. Several prototypes have already been designed, submitted for fabrication and some of them tested with X-ray sources and particles in a beam. Analog power consumption has been limited by optimizing the Q/C of the sensor using Explorer chips. Promising but preliminary first results have also been obtained with a prototype ALPIDE. Radiation tolerance up to the ALICE requirements has also been verified.

Miniature fiber Bragg grating sensor interrogator (FBG-Transceiver) system

NASA Astrophysics Data System (ADS)

Mendoza, Edgar A.; Kempen, Cornelia; Lopatin, Craig

2007-04-01

This paper describes recent progress conducted towards the development of a miniature fiber Bragg grating sensor interrogator (FBG-Transceiver TM) system based on multi-channel integrated optic sensor (InOSense TM) microchip technology. The hybrid InOSense TM microchip technology enables the integration of all of the functionalities, both passive and active, of conventional bench top FBG sensor interrogator systems, packaged in a miniaturized, low power operation, 2-cm x 5-cm package suitable for the long-term structural health monitoring in applications where size, weight, and power are critical for operation. The FBG-Transceiver system uses active optoelectronic components monolithically integrated to the InOSense TM microchip, a microprocessor controlled signal processing electronics board capable of processing the FBG sensors signals related to stress-strain and temperature as well as vibration and acoustics. The FBG-Transceiver TM system represents a new, reliable, highly robust technology that can be used to accurately monitor the status of an array of distributed fiber optic Bragg grating sensors installed in critical infrastructures. Its miniature package, low power operation, and state-of-the-art data communications architecture, all at a very affordable price makes it a very attractive solution for a large number of SHM/NDI applications in aerospace, naval and maritime industry, civil structures like bridges, buildings and dams, the oil and chemical industry, and for homeland security applications. The miniature, cost-efficient FBG-Transceiver TM system is poised to revolutionize the field of structural health monitoring and nondestructive inspection market. The sponsor of this program is NAVAIR under a DOD SBIR contract.

Methods and Systems for Configuring Sensor Acquisition Based on Pressure Steps

NASA Technical Reports Server (NTRS)

DeDonato, Mathew (Inventor)

2015-01-01

Technologies are provided for underwater measurements. A system includes an underwater vessels including: a plurality of sensors disposed thereon for measuring underwater properties; and a programmable controller configured to selectively activate the plurality of sensors based at least in part on underwater pressure. A user may program at what pressure ranges certain sensors are activated to measure selected properties, and may also program the ascent/descent rate of the underwater vessel, which is correlated with the underwater pressure.

Application of wireless sensor network technology in logistics information system

NASA Astrophysics Data System (ADS)

Xu, Tao; Gong, Lina; Zhang, Wei; Li, Xuhong; Wang, Xia; Pan, Wenwen

2017-04-01

This paper introduces the basic concepts of active RFID (WSN-ARFID) based on wireless sensor networks and analyzes the shortcomings of the existing RFID-based logistics monitoring system. Integrated wireless sensor network technology and the scrambling point of RFID technology. A new real-time logistics detection system based on WSN and RFID, a model of logistics system based on WSN-ARFID is proposed, and the feasibility of this technology applied to logistics field is analyzed.

New optical sensor systems for high-resolution satellite, airborne and terrestrial imaging systems

NASA Astrophysics Data System (ADS)

Eckardt, Andreas; Börner, Anko; Lehmann, Frank

2007-10-01

The department of Optical Information Systems (OS) at the Institute of Robotics and Mechatronics of the German Aerospace Center (DLR) has more than 25 years experience with high-resolution imaging technology. The technology changes in the development of detectors, as well as the significant change of the manufacturing accuracy in combination with the engineering research define the next generation of spaceborne sensor systems focusing on Earth observation and remote sensing. The combination of large TDI lines, intelligent synchronization control, fast-readable sensors and new focal-plane concepts open the door to new remote-sensing instruments. This class of instruments is feasible for high-resolution sensor systems regarding geometry and radiometry and their data products like 3D virtual reality. Systemic approaches are essential for such designs of complex sensor systems for dedicated tasks. The system theory of the instrument inside a simulated environment is the beginning of the optimization process for the optical, mechanical and electrical designs. Single modules and the entire system have to be calibrated and verified. Suitable procedures must be defined on component, module and system level for the assembly test and verification process. This kind of development strategy allows the hardware-in-the-loop design. The paper gives an overview about the current activities at DLR in the field of innovative sensor systems for photogrammetric and remote sensing purposes.

Integrated cable vibration control system using wireless sensors

NASA Astrophysics Data System (ADS)

Jeong, Seunghoo; Cho, Soojin; Sim, Sung-Han

2017-04-01

As the number of long-span bridges is increasing worldwide, maintaining their structural integrity and safety become an important issue. Because the stay cable is a critical member in most long-span bridges and vulnerable to wind-induced vibrations, vibration mitigation has been of interest both in academia and practice. While active and semi-active control schemes are known to be quite effective in vibration reduction compared to the passive control, requirements for equipment including data acquisition, control devices, and power supply prevent a widespread adoption in real-world applications. This study develops an integrated system for vibration control of stay-cables using wireless sensors implementing a semi-active control. Arduino, a low-cost single board system, is employed with a MEMS digital accelerometer and a Zigbee wireless communication module to build the wireless sensor. The magneto-rheological (MR) damper is selected as a damping device, controlled by an optimal control algorithm implemented on the Arduino sensing system. The developed integrated system is tested in a laboratory environment using a cable to demonstrate the effectiveness of the proposed system on vibration reduction. The proposed system is shown to reduce the vibration of stay-cables with low operating power effectively.

Observational Constraints on Cloud Feedbacks: The Role of Active Satellite Sensors

NASA Astrophysics Data System (ADS)

Winker, David; Chepfer, Helene; Noel, Vincent; Cai, Xia

2017-11-01

Cloud profiling from active lidar and radar in the A-train satellite constellation has significantly advanced our understanding of clouds and their role in the climate system. Nevertheless, the response of clouds to a warming climate remains one of the largest uncertainties in predicting climate change and for the development of adaptions to change. Both observation of long-term changes and observational constraints on the processes responsible for those changes are necessary. We review recent progress in our understanding of the cloud feedback problem. Capabilities and advantages of active sensors for observing clouds are discussed, along with the importance of active sensors for deriving constraints on cloud feedbacks as an essential component of a global climate observing system.

An Ambulatory System for Gait Monitoring Based on Wireless Sensorized Insoles

PubMed Central

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

2015-01-01

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

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

PubMed

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

2015-07-09

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

Development of Sic Gas Sensor Systems

NASA Technical Reports Server (NTRS)

Hunter, G. W.; Neudeck, P. G.; Okojie, R. S.; Beheim, G. M.; Thomas, V.; Chen, L.; Lukco, D.; Liu, C. C.; Ward, B.; Makel, D.

2002-01-01

Silicon carbide (SiC) based gas sensors have significant potential to address the gas sensing needs of aerospace applications such as emission monitoring, fuel leak detection, and fire detection. However, in order to reach that potential, a range of technical challenges must be overcome. These challenges go beyond the development of the basic sensor itself and include the need for viable enabling technologies to make a complete gas sensor system: electrical contacts, packaging, and transfer of information from the sensor to the outside world. This paper reviews the status at NASA Glenn Research Center of SiC Schottky diode gas sensor development as well as that of enabling technologies supporting SiC gas sensor system implementation. A vision of a complete high temperature microfabricated SiC gas sensor system is proposed. In the long-term, it is believed that improvements in the SiC semiconductor material itself could have a dramatic effect on the performance of SiC gas sensor systems.

Advancing from offline to online activity recognition with wearable sensors.

PubMed

Ermes, Miikka; Parkka, Juha; Cluitmans, Luc

2008-01-01

Activity recognition with wearable sensors could motivate people to perform a variety of different sports and other physical exercises. We have earlier developed algorithms for offline analysis of activity data collected with wearable sensors. In this paper, we present our current progress in advancing the platform for the existing algorithms to an online version, onto a PDA. Acceleration data are obtained from wireless motion bands which send the 3D raw acceleration signals via a Bluetooth link to the PDA which then performs the data collection, feature extraction and activity classification. As a proof-of-concept, the online activity system was tested with three subjects. All of them performed at least 5 minutes of each of the following activities: lying, sitting, standing, walking, running and cycling with an exercise bike. The average second-by-second classification accuracies for the subjects were 99%, 97%, and 82 %. These results suggest that earlier developed offline analysis methods for the acceleration data obtained from wearable sensors can be successfully implemented in an online activity recognition application.

A Multi-Agent System Architecture for Sensor Networks

PubMed Central

Fuentes-Fernández, Rubén; Guijarro, María; Pajares, Gonzalo

2009-01-01

The design of the control systems for sensor networks presents important challenges. Besides the traditional problems about how to process the sensor data to obtain the target information, engineers need to consider additional aspects such as the heterogeneity and high number of sensors, and the flexibility of these networks regarding topologies and the sensors in them. Although there are partial approaches for resolving these issues, their integration relies on ad hoc solutions requiring important development efforts. In order to provide an effective approach for this integration, this paper proposes an architecture based on the multi-agent system paradigm with a clear separation of concerns. The architecture considers sensors as devices used by an upper layer of manager agents. These agents are able to communicate and negotiate services to achieve the required functionality. Activities are organized according to roles related with the different aspects to integrate, mainly sensor management, data processing, communication and adaptation to changes in the available devices and their capabilities. This organization largely isolates and decouples the data management from the changing network, while encouraging reuse of solutions. The use of the architecture is facilitated by a specific modelling language developed through metamodelling. A case study concerning a generic distributed system for fire fighting illustrates the approach and the comparison with related work. PMID:22303172

Intelligent Sensors: An Integrated Systems Approach

NASA Technical Reports Server (NTRS)

Mahajan, Ajay; Chitikeshi, Sanjeevi; Bandhil, Pavan; Utterbach, Lucas; Figueroa, Fernando

2005-01-01

The need for intelligent sensors as a critical component for Integrated System Health Management (ISHM) is fairly well recognized by now. Even the definition of what constitutes an intelligent sensor (or smart sensor) is well documented and stems from an intuitive desire to get the best quality measurement data that forms the basis of any complex health monitoring and/or management system. If the sensors, i.e. the elements closest to the measurand, are unreliable then the whole system works with a tremendous handicap. Hence, there has always been a desire to distribute intelligence down to the sensor level, and give it the ability to assess its own health thereby improving the confidence in the quality of the data at all times. This paper proposes the development of intelligent sensors as an integrated systems approach, i.e. one treats the sensors as a complete system with its own sensing hardware (the traditional sensor), A/D converters, processing and storage capabilities, software drivers, self-assessment algorithms, communication protocols and evolutionary methodologies that allow them to get better with time. Under a project being undertaken at the NASA Stennis Space Center, an integrated framework is being developed for the intelligent monitoring of smart elements. These smart elements can be sensors, actuators or other devices. The immediate application is the monitoring of the rocket test stands, but the technology should be generally applicable to the Intelligent Systems Health Monitoring (ISHM) vision. This paper outlines some fundamental issues in the development of intelligent sensors under the following two categories: Physical Intelligent Sensors (PIS) and Virtual Intelligent Sensors (VIS).

CMOS Active Pixel Sensors for Low Power, Highly Miniaturized Imaging Systems

NASA Technical Reports Server (NTRS)

Fossum, Eric R.

1996-01-01

The complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) technology has been developed over the past three years by NASA at the Jet Propulsion Laboratory, and has reached a level of performance comparable to CCDs with greatly increased functionality but at a very reduced power level.

Wearable PPG sensor based alertness scoring system.

PubMed

Dey, Jishnu; Bhowmik, Tanmoy; Sahoo, Saswata; Tiwari, Vijay Narayan

2017-07-01

Quantifying mental alertness in today's world is important as it enables the person to adopt lifestyle changes for better work efficiency. Miniaturized sensors in wearable devices have facilitated detection/monitoring of mental alertness. Photoplethysmography (PPG) sensors through Heart Rate Variability (HRV) offer one such opportunity by providing information about one's daily alertness levels without requiring any manual interference from the user. In this paper, a smartwatch based alertness estimation system is proposed. Data collected from PPG sensor of smartwatch is processed and fed to machine learning based model to get a continuous alertness score. Utility functions are designed based on statistical analysis to give a quality score on different stages of alertness such as awake, long sleep and short duration power nap. An intelligent data collection approach is proposed in collaboration with the motion sensor in the smartwatch to reduce battery drainage. Overall, our proposed wearable based system provides a detailed analysis of alertness over a period in a systematic and optimized manner. We were able to achieve an accuracy of 80.1% for sleep/awake classification along with alertness score. This opens up the possibility for quantifying alertness levels using a single PPG sensor for better management of health related activities including sleep.

Distributed sensor coordination for advanced energy systems

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

Tumer, Kagan

Motivation: The ability to collect key system level information is critical to the safe, efficient and reliable operation of advanced power systems. Recent advances in sensor technology have enabled some level of decision making directly at the sensor level. However, coordinating large numbers of sensors, particularly heterogeneous sensors, to achieve system level objectives such as predicting plant efficiency, reducing downtime or predicting outages requires sophisticated coordination algorithms. Indeed, a critical issue in such systems is how to ensure the interaction of a large number of heterogenous system components do not interfere with one another and lead to undesirable behavior. Objectivesmore » and Contributions: The long-term objective of this work is to provide sensor deployment, coordination and networking algorithms for large numbers of sensors to ensure the safe, reliable, and robust operation of advanced energy systems. Our two specific objectives are to: 1. Derive sensor performance metrics for heterogeneous sensor networks. 2. Demonstrate effectiveness, scalability and reconfigurability of heterogeneous sensor network in advanced power systems. The key technical contribution of this work is to push the coordination step to the design of the objective functions of the sensors, allowing networks of heterogeneous sensors to be controlled. By ensuring that the control and coordination is not specific to particular sensor hardware, this approach enables the design and operation of large heterogeneous sensor networks. In addition to the coordination coordination mechanism, this approach allows the system to be reconfigured in response to changing needs (e.g., sudden external events requiring new responses) or changing sensor network characteristics (e.g., sudden changes to plant condition). Impact: The impact of this work extends to a large class of problems relevant to the National Energy Technology Laboratory including sensor placement

Hydrogen Research for Spaceport and Space-Based Applications: Hydrogen Sensors and Systems. Part 2

NASA Technical Reports Server (NTRS)

Anderson, Tim; Balaban, Canan

2008-01-01

The activities presented are a broad based approach to advancing key hydrogen related technologies in areas such as fuel cells, hydrogen production, and distributed sensors for hydrogen-leak detection, laser instrumentation for hydrogen-leak detection, and cryogenic transport and storage. Presented are the results from research projects, education and outreach activities, system and trade studies. The work will aid in advancing the state-of-the-art for several critical technologies related to the implementation of a hydrogen infrastructure. Activities conducted are relevant to a number of propulsion and power systems for terrestrial, aeronautics and aerospace applications. Sensor systems research was focused on hydrogen leak detection and smart sensors with adaptive feedback control for fuel cells. The goal was to integrate multifunction smart sensors, low-power high-efficiency wireless circuits, energy harvesting devices, and power management circuits in one module. Activities were focused on testing and demonstrating sensors in a realistic environment while also bringing them closer to production and commercial viability for eventual use in the actual operating environment.

Applications of SPICE for modeling miniaturized biomedical sensor systems

NASA Technical Reports Server (NTRS)

Mundt, C. W.; Nagle, H. T.

2000-01-01

This paper proposes a model for a miniaturized signal conditioning system for biopotential and ion-selective electrode arrays. The system consists of three main components: sensors, interconnections, and signal conditioning chip. The model for this system is based on SPICE. Transmission-line based equivalent circuits are used to represent the sensors, lumped resistance-capacitance circuits describe the interconnections, and a model for the signal conditioning chip is extracted from its layout. A system for measurements of biopotentials and ionic activities can be miniaturized and optimized for cardiovascular applications based on the development of an integrated SPICE system model of its electrochemical, interconnection, and electronic components.

Recent CESAR (Center for Engineering Systems Advanced Research) research activities in sensor based reasoning for autonomous machines

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

Pin, F.G.; de Saussure, G.; Spelt, P.F.

1988-01-01

This paper describes recent research activities at the Center for Engineering Systems Advanced Research (CESAR) in the area of sensor based reasoning, with emphasis being given to their application and implementation on our HERMIES-IIB autonomous mobile vehicle. These activities, including navigation and exploration in a-priori unknown and dynamic environments, goal recognition, vision-guided manipulation and sensor-driven machine learning, are discussed within the framework of a scenario in which an autonomous robot is asked to navigate through an unknown dynamic environment, explore, find and dock at the panel, read and understand the status of the panel's meters and dials, learn the functioningmore » of a process control panel, and successfully manipulate the control devices of the panel to solve a maintenance emergency problems. A demonstration of the successful implementation of the algorithms on our HERMIES-IIB autonomous robot for resolution of this scenario is presented. Conclusions are drawn concerning the applicability of the methodologies to more general classes of problems and implications for future work on sensor-driven reasoning for autonomous robots are discussed. 8 refs., 3 figs.« less

Heimdall System for MSSS Sensor Tasking

NASA Astrophysics Data System (ADS)

Herz, A.; Jones, B.; Herz, E.; George, D.; Axelrad, P.; Gehly, S.

coordinated sensor usage, and tasking schedules driven by catalog improvement goals (reduced overall covariance, etc.). The improved performance also enables more responsive sensor tasking to address external events, newly detected objects, newly detected object activity, and sensor anomalies. Instead of having to wait until the next day's scheduling phase, events can be addressed with new tasking schedules immediately (within seconds or minutes). Perhaps the most important benefit is improved SSA based on an overall improvement to the quality of the space catalog. By driving sensor tasking and scheduling based on predicted Information Gain and other relevant factors, better decisions are made in the application of available sensor resources, leading to an improved catalog and better information about the objects of most interest. The Heimdall software solution provides a configurable, automated system to improve sensor tasking efficiency and responsiveness for SSA applications. The FISST algorithms for Track Prioritization, SSA specific task and resource attributes, Scheduler algorithms, and configurable SSA-specific Figure-of-Merit together provide optimized and tunable scheduling for the Maui Space Surveillance Site and possibly other sites and organizations across the U.S. military and for allies around the world.

Evolutionary Design of Convolutional Neural Networks for Human Activity Recognition in Sensor-Rich Environments.

PubMed

Baldominos, Alejandro; Saez, Yago; Isasi, Pedro

2018-04-23

Human activity recognition is a challenging problem for context-aware systems and applications. It is gaining interest due to the ubiquity of different sensor sources, wearable smart objects, ambient sensors, etc. This task is usually approached as a supervised machine learning problem, where a label is to be predicted given some input data, such as the signals retrieved from different sensors. For tackling the human activity recognition problem in sensor network environments, in this paper we propose the use of deep learning (convolutional neural networks) to perform activity recognition using the publicly available OPPORTUNITY dataset. Instead of manually choosing a suitable topology, we will let an evolutionary algorithm design the optimal topology in order to maximize the classification F1 score. After that, we will also explore the performance of committees of the models resulting from the evolutionary process. Results analysis indicates that the proposed model was able to perform activity recognition within a heterogeneous sensor network environment, achieving very high accuracies when tested with new sensor data. Based on all conducted experiments, the proposed neuroevolutionary system has proved to be able to systematically find a classification model which is capable of outperforming previous results reported in the state-of-the-art, showing that this approach is useful and improves upon previously manually-designed architectures.

An error-based micro-sensor capture system for real-time motion estimation

NASA Astrophysics Data System (ADS)

Yang, Lin; Ye, Shiwei; Wang, Zhibo; Huang, Zhipei; Wu, Jiankang; Kong, Yongmei; Zhang, Li

2017-10-01

A wearable micro-sensor motion capture system with 16 IMUs and an error-compensatory complementary filter algorithm for real-time motion estimation has been developed to acquire accurate 3D orientation and displacement in real life activities. In the proposed filter algorithm, the gyroscope bias error, orientation error and magnetic disturbance error are estimated and compensated, significantly reducing the orientation estimation error due to sensor noise and drift. Displacement estimation, especially for activities such as jumping, has been the challenge in micro-sensor motion capture. An adaptive gait phase detection algorithm has been developed to accommodate accurate displacement estimation in different types of activities. The performance of this system is benchmarked with respect to the results of VICON optical capture system. The experimental results have demonstrated effectiveness of the system in daily activities tracking, with estimation error 0.16 ± 0.06 m for normal walking and 0.13 ± 0.11 m for jumping motions. Research supported by the National Natural Science Foundation of China (Nos. 61431017, 81272166).

Fluidic Sensor Temperature Indicating System.

DTIC Science & Technology

A fluidic sensor temperature indicating system designed by Honeywell Inc was tested on a T56 engine during dynamometer calibration. It was also...based on the sensor being mounted in a T56 engine showed a hot gas temperature drop from 1970F at the sensor entrance to 1760F in the sensor pulsation

iCalm: wearable sensor and network architecture for wirelessly communicating and logging autonomic activity.

PubMed

Fletcher, Richard Ribon; Dobson, Kelly; Goodwin, Matthew S; Eydgahi, Hoda; Wilder-Smith, Oliver; Fernholz, David; Kuboyama, Yuta; Hedman, Elliott Bruce; Poh, Ming-Zher; Picard, Rosalind W

2010-03-01

Widespread use of affective sensing in healthcare applications has been limited due to several practical factors, such as lack of comfortable wearable sensors, lack of wireless standards, and lack of low-power affordable hardware. In this paper, we present a new low-cost, low-power wireless sensor platform implemented using the IEEE 802.15.4 wireless standard, and describe the design of compact wearable sensors for long-term measurement of electrodermal activity, temperature, motor activity, and photoplethysmography. We also illustrate the use of this new technology for continuous long-term monitoring of autonomic nervous system and motion data from active infants, children, and adults. We describe several new applications enabled by this system, discuss two specific wearable designs for the wrist and foot, and present sample data.

Smart healthcare textile sensor system for unhindered-pervasive health monitoring

NASA Astrophysics Data System (ADS)

Rai, Pratyush; Kumar, Prashanth S.; Oh, Sechang; Kwon, Hyeokjun; Mathur, Gyanesh N.; Varadan, Vijay K.; Agarwal, M. P.

2012-04-01

Simultaneous monitoring of physiological parameters- multi-lead Electrocardiograph (ECG), Heart rate variability, and blood pressure- is imperative to all forms of medical treatments. Using an array of signal recording devices imply that the patient will have to be confined to a bed. Textiles offer durable platform for embedded sensor and communication systems. The smart healthcare textile, presented here, is a mobile system for remote/wireless data recording and conditioning. The wireless textile system has been designed to monitor a patient in a non-obstructive way. It has a potential for facilitating point of care medicine and streamlining ambulatory medicine. The sensor systems were designed and fabricated with textile based components for easy integration on textile platform. An innovative plethysmographic blood pressure monitoring system was designed and tested as an alternative to inflatable blood pressure sphygmomanometer. Flexible dry electrodes technology was implemented for ECG. The sensor systems were tested and conditioned to daily activities of patients, which is not permissible with halter type systems. The signal quality was assessed for it applicability to medical diagnosis. The results were used to corroborate smart textile sensor system's ability to function as a point of care system that can provide quality healthcare.

Optical Breath Gas Extravehicular Activity Sensor for the Advanced Portable Life Support System

NASA Technical Reports Server (NTRS)

Wood, William R.; Casias, Miguel E.; Pilgrim, Jeffrey S.; Chullen, Cinda; Campbell, Colin

2016-01-01

The function of the infrared gas transducer used during extravehicular activity (EVA) in the current space suit is to measure and report the concentration of carbon dioxide (CO2) in the ventilation loop. The next generation portable life support system (PLSS) requires highly accurate CO2 sensing technology with performance beyond that presently in use on the International Space Station extravehicular mobility unit (EMU). Further, that accuracy needs to be provided over the full operating pressure range of the suit (3 to 25 psia). Accommodation within space suits demands that optical sensors meet stringent size, weight, and power requirements. A laser diode (LD) sensor based on infrared absorption spectroscopy is being developed for this purpose by Vista Photonics, Inc. Version 1.0 prototype devices were delivered to NASA Johnson Space Center (JSC) in September 2011. The prototypes were upgraded with more sophisticated communications and faster response times to version 2.0 and delivered to JSC in July 2012. The sensors incorporate a laser diode based CO2 channel that also includes an incidental water vapor (humidity) measurement. The prototypes are controlled digitally with an field-programmable gate array microcontroller architecture. Based on the results of the iterative instrument development, further prototype development and testing of instruments were performed leveraging the lessons learned where feasible. The present development extends and upgrades the earlier hardware for the advanced PLSS 2.5 prototypes for testing at JSC. The prototypes provide significantly enhanced accuracy for water vapor measurement and eliminate wavelength drift affecting the earlier versions. Various improvements to the electronics and gas sampling are currently being advanced including the companion development of engineering development units that will ultimately be capable of radiation tolerance. The combination of low power electronics with the performance of a long wavelength

High pressure fiber optic sensor system

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

Guida, Renato; Xia, Hua; Lee, Boon K

2013-11-26

The present application provides a fiber optic sensor system. The fiber optic sensor system may include a small diameter bellows, a large diameter bellows, and a fiber optic pressure sensor attached to the small diameter bellows. Contraction of the large diameter bellows under an applied pressure may cause the small diameter bellows to expand such that the fiber optic pressure sensor may measure the applied pressure.

Secured network sensor-based defense system

NASA Astrophysics Data System (ADS)

Wei, Sixiao; Shen, Dan; Ge, Linqiang; Yu, Wei; Blasch, Erik P.; Pham, Khanh D.; Chen, Genshe

2015-05-01

Network sensor-based defense (NSD) systems have been widely used to defend against cyber threats. Nonetheless, if the adversary finds ways to identify the location of monitor sensors, the effectiveness of NSD systems can be reduced. In this paper, we propose both temporal and spatial perturbation based defense mechanisms to secure NSD systems and make the monitor sensor invisible to the adversary. The temporal-perturbation based defense manipulates the timing information of published data so that the probability of successfully recognizing monitor sensors can be reduced. The spatial-perturbation based defense dynamically redeploys monitor sensors in the network so that the adversary cannot obtain the complete information to recognize all of the monitor sensors. We carried out experiments using real-world traffic traces to evaluate the effectiveness of our proposed defense mechanisms. Our data shows that our proposed defense mechanisms can reduce the attack accuracy of recognizing detection sensors.

Real-Time Performance of a Self-Powered Environmental IoT Sensor Network System.

PubMed

Wu, Fan; Rüdiger, Christoph; Yuce, Mehmet Rasit

2017-02-01

Wireless sensor networks (WSNs) play an increasingly important role in monitoring applications in many areas. With the emergence of the Internet-of-Things (IoT), many more lowpower sensors will need to be deployed in various environments to collect and monitor data about environmental factors in real time. Providing power supply to these sensor nodes becomes a critical challenge for realizations of IoT applications as sensor nodes are normally battery-powered and have a limited lifetime. This paper proposes a wireless sensor network that is powered by solar energy harvesting. The sensor network monitors the environmental data with low-power sensor electronics and forms a network using multiple XBee wireless modules. A detailed performance analysis of the network system under solar energy harvesting has been presented. The sensor network system and the proposed energy-harvesting techniques are configured to achieve a continuous energy source for the sensor network. The proposed energy-harvesting system has been successfully designed to enable an energy solution in order to keep sensor nodes active and reliable for a whole day. The paper also outlines some of our experiences in real-time implementation of a sensor network system with energy harvesting.

Real-Time Performance of a Self-Powered Environmental IoT Sensor Network System

PubMed Central

Wu, Fan; Rüdiger, Christoph; Yuce, Mehmet Rasit

2017-01-01

Wireless sensor networks (WSNs) play an increasingly important role in monitoring applications in many areas. With the emergence of the Internet-of-Things (IoT), many more low-power sensors will need to be deployed in various environments to collect and monitor data about environmental factors in real time. Providing power supply to these sensor nodes becomes a critical challenge for realizations of IoT applications as sensor nodes are normally battery-powered and have a limited lifetime. This paper proposes a wireless sensor network that is powered by solar energy harvesting. The sensor network monitors the environmental data with low-power sensor electronics and forms a network using multiple XBee wireless modules. A detailed performance analysis of the network system under solar energy harvesting has been presented. The sensor network system and the proposed energy-harvesting techniques are configured to achieve a continuous energy source for the sensor network. The proposed energy-harvesting system has been successfully designed to enable an energy solution in order to keep sensor nodes active and reliable for a whole day. The paper also outlines some of our experiences in real-time implementation of a sensor network system with energy harvesting. PMID:28157148

POF-IMU sensor system: A fusion between inertial measurement units and POF sensors for low-cost and highly reliable systems

NASA Astrophysics Data System (ADS)

Leal-Junior, Arnaldo G.; Vargas-Valencia, Laura; dos Santos, Wilian M.; Schneider, Felipe B. A.; Siqueira, Adriano A. G.; Pontes, Maria José; Frizera, Anselmo

2018-07-01

This paper presents a low cost and highly reliable system for angle measurement based on a sensor fusion between inertial and fiber optic sensors. The system consists of the sensor fusion through Kalman filter of two inertial measurement units (IMUs) and an intensity variation-based polymer optical fiber (POF) curvature sensor. In addition, the IMU was applied as a reference for a compensation technique of POF curvature sensor hysteresis. The proposed system was applied on the knee angle measurement of a lower limb exoskeleton in flexion/extension cycles and in gait analysis. Results show the accuracy of the system, where the Root Mean Square Error (RMSE) between the POF-IMU sensor system and the encoder was below 4° in the worst case and about 1° in the best case. Then, the POF-IMU sensor system was evaluated as a wearable sensor for knee joint angle assessment without the exoskeleton, where its suitability for this purpose was demonstrated. The results obtained in this paper pave the way for future applications of sensor fusion between electronic and fiber optic sensors in movement analysis.

Evolutionary Design of Convolutional Neural Networks for Human Activity Recognition in Sensor-Rich Environments

PubMed Central

2018-01-01

Human activity recognition is a challenging problem for context-aware systems and applications. It is gaining interest due to the ubiquity of different sensor sources, wearable smart objects, ambient sensors, etc. This task is usually approached as a supervised machine learning problem, where a label is to be predicted given some input data, such as the signals retrieved from different sensors. For tackling the human activity recognition problem in sensor network environments, in this paper we propose the use of deep learning (convolutional neural networks) to perform activity recognition using the publicly available OPPORTUNITY dataset. Instead of manually choosing a suitable topology, we will let an evolutionary algorithm design the optimal topology in order to maximize the classification F1 score. After that, we will also explore the performance of committees of the models resulting from the evolutionary process. Results analysis indicates that the proposed model was able to perform activity recognition within a heterogeneous sensor network environment, achieving very high accuracies when tested with new sensor data. Based on all conducted experiments, the proposed neuroevolutionary system has proved to be able to systematically find a classification model which is capable of outperforming previous results reported in the state-of-the-art, showing that this approach is useful and improves upon previously manually-designed architectures. PMID:29690587

Highly Portable, Sensor-Based System for Human Fall Monitoring

PubMed Central

Mao, Aihua; Ma, Xuedong; He, Yinan; Luo, Jie

2017-01-01

Falls are a very dangerous situation especially among elderly people, because they may lead to fractures, concussion, and other injuries. Without timely rescue, falls may even endanger their lives. The existing optical sensor-based fall monitoring systems have some disadvantages, such as limited monitoring range and inconvenience to carry for users. Furthermore, the fall detection system based only on an accelerometer often mistakenly determines some activities of daily living (ADL) as falls, leading to low accuracy in fall detection. We propose a human fall monitoring system consisting of a highly portable sensor unit including a triaxis accelerometer, a triaxis gyroscope, and a triaxis magnetometer, and a mobile phone. With the data from these sensors, we obtain the acceleration and Euler angle (yaw, pitch, and roll), which represents the orientation of the user’s body. Then, a proposed fall detection algorithm was used to detect falls based on the acceleration and Euler angle. With this monitoring system, we design a series of simulated falls and ADL and conduct the experiment by placing the sensors on the shoulder, waist, and foot of the subjects. Through the experiment, we re-identify the threshold of acceleration for accurate fall detection and verify the best body location to place the sensors by comparing the detection performance on different body segments. We also compared this monitoring system with other similar works and found that better fall detection accuracy and portability can be achieved by our system. PMID:28902149

Highly Portable, Sensor-Based System for Human Fall Monitoring.

PubMed

Mao, Aihua; Ma, Xuedong; He, Yinan; Luo, Jie

2017-09-13

Falls are a very dangerous situation especially among elderly people, because they may lead to fractures, concussion, and other injuries. Without timely rescue, falls may even endanger their lives. The existing optical sensor-based fall monitoring systems have some disadvantages, such as limited monitoring range and inconvenience to carry for users. Furthermore, the fall detection system based only on an accelerometer often mistakenly determines some activities of daily living (ADL) as falls, leading to low accuracy in fall detection. We propose a human fall monitoring system consisting of a highly portable sensor unit including a triaxis accelerometer, a triaxis gyroscope, and a triaxis magnetometer, and a mobile phone. With the data from these sensors, we obtain the acceleration and Euler angle (yaw, pitch, and roll), which represents the orientation of the user's body. Then, a proposed fall detection algorithm was used to detect falls based on the acceleration and Euler angle. With this monitoring system, we design a series of simulated falls and ADL and conduct the experiment by placing the sensors on the shoulder, waist, and foot of the subjects. Through the experiment, we re-identify the threshold of acceleration for accurate fall detection and verify the best body location to place the sensors by comparing the detection performance on different body segments. We also compared this monitoring system with other similar works and found that better fall detection accuracy and portability can be achieved by our system.

Bluetooth Roaming for Sensor Network System in Clinical Environment.

PubMed

Kuroda, Tomohiro; Noma, Haruo; Takase, Kazuhiko; Sasaki, Shigeto; Takemura, Tadamasa

2015-01-01

A sensor network is key infrastructure for advancing a hospital information system (HIS). The authors proposed a method to provide roaming functionality for Bluetooth to realize a Bluetooth-based sensor network, which is suitable to connect clinical devices. The proposed method makes the average response time of a Bluetooth connection less than one second by making the master device repeat the inquiry process endlessly and modifies parameters of the inquiry process. The authors applied the developed sensor network for daily clinical activities in an university hospital, and confirmed the stabilitya and effectiveness of the sensor network. As Bluetooth becomes a quite common wireless interface for medical devices, the proposed protocol that realizes Bluetooth-based sensor network enables HIS to equip various clinical devices and, consequently, lets information and communication technologies advance clinical services.

Damage Detection Sensor System for Aerospace and Multiple Applications

NASA Technical Reports Server (NTRS)

Williams, M.; Lewis, M.; Gibson, T.; Medelius, P.; Lane, J.

2017-01-01

The damage detection sensory system is an intelligent damage detection ‘skin’ that can be embedded into rigid or flexible structures, providing a lightweight capability for in-situ health monitoring for applications such as spacecraft, expandable or inflatable structures, extravehicular activities (EVA) suits, smart wearables, and other applications where diagnostic impact damage monitoring might be critical. The sensor systems can be customized for detecting location, damage size, and depth, with velocity options and can be designed for particular environments for monitoring of impact or physical damage to a structure. The operation of the sensor detection system is currently based on the use of parallel conductive traces placed on a firm or flexible surface. Several detection layers can be implemented, where alternate layers are arranged in orthogonal direction with respect to the adjacent layers allowing for location and depth calculations. Increased flexibility of the damage detection sensor system designs will also be introduced.

Sensor Systems for Space Life Sciences

NASA Technical Reports Server (NTRS)

Somps, Chris J.; Hines, John W.; Connolly, John P. (Technical Monitor)

1995-01-01

Sensors 2000! (S2K!) is a NASA Ames Research Center engineering initiative designed to provide biosensor and bio-instrumentation systems technology expertise to NASA's life sciences spaceflight programs. S2K! covers the full spectrum of sensor technology applications, ranging from spaceflight hardware design and fabrication to advanced technology development, transfer and commercialization. S2K! is currently developing sensor systems for space biomedical applications on BION (a Russian biosatellite focused on Rhesus Monkey physiology) and NEUROLAB (a Space Shuttle flight devoted to neuroscience). It's Advanced Technology Development-Biosensors (ATD-B) project focuses efforts in five principle areas: biotelemetry Systems, chemical and biological sensors, physiological sensors, advanced instrumentation architectures, and data and information management. Technologies already developed and tested included, application-specific sensors, preamplifier hybrids, modular programmable signal conditioners, power conditioning and distribution systems, and a fully implantable dual channel biotelemeter. Systems currently under development include a portable receiver system compatible with an off-the-shelf analog biotelemeter, a 4 channel digital biotelemetry system which monitors pH, a multichannel, g-processor based PCM biotelemetry system, and hand-held personal monitoring systems. S2K! technology easily lends itself to telescience and telemedicine applications as a front-end measurement and data acquisition device, suitable for obtaining and configuring physiological information, and processing that information under control from a remote location.

An Optical Actuation System and Curvature Sensor for a MR-compatible Active Needle

PubMed Central

Ryu, Seok Chang; Quek, Zhan Fan; Renaud, Pierre; Black, Richard J.; Daniel, Bruce L.; Cutkosky, Mark R.

2015-01-01

A side optical actuation method is presented for a slender MR-compatible active needle. The needle includes an active region with a shape memory alloy (SMA) wire actuator, where the wire generates a contraction force when optically heated by a laser delivered though optical fibers, producing needle tip bending. A prototype, with multiple side heating spots, demonstrates twice as fast an initial response compared to fiber tip heating when 0.8 W of optical power is applied. A single-ended optical sensor with a gold reflector is also presented to measure the curvature as a function of optical transmission loss. Preliminary tests with the sensor prototype demonstrate approximately linear response and a repeatable signal, independent of the bending history. PMID:26509099

Theoretical and experimental investigations of sensor location for optimal aeroelastic system state estimation

NASA Technical Reports Server (NTRS)

Liu, G.

1985-01-01

One of the major concerns in the design of an active control system is obtaining the information needed for effective feedback. This involves the combination of sensing and estimation. A sensor location index is defined as the weighted sum of the mean square estimation errors in which the sensor locations can be regarded as estimator design parameters. The design goal is to choose these locations to minimize the sensor location index. The choice of the number of sensors is a tradeoff between the estimation quality based upon the same performance index and the total costs of installing and maintaining extra sensors. An experimental study for choosing the sensor location was conducted on an aeroelastic system. The system modeling which includes the unsteady aerodynamics model developed by Stephen Rock was improved. Experimental results verify the trend of the theoretical predictions of the sensor location index for different sensor locations at various wind speeds.

Sensor systems for prognostics and health management.

PubMed

Cheng, Shunfeng; Azarian, Michael H; Pecht, Michael G

2010-01-01

Prognostics and health management (PHM) is an enabling discipline consisting of technologies and methods to assess the reliability of a product in its actual life cycle conditions to determine the advent of failure and mitigate system risk. Sensor systems are needed for PHM to monitor environmental, operational, and performance-related characteristics. The gathered data can be analyzed to assess product health and predict remaining life. In this paper, the considerations for sensor system selection for PHM applications, including the parameters to be measured, the performance needs, the electrical and physical attributes, reliability, and cost of the sensor system, are discussed. The state-of-the-art sensor systems for PHM and the emerging trends in technologies of sensor systems for PHM are presented.

Sensor Systems for Prognostics and Health Management

PubMed Central

Cheng, Shunfeng; Azarian, Michael H.; Pecht, Michael G.

2010-01-01

Prognostics and health management (PHM) is an enabling discipline consisting of technologies and methods to assess the reliability of a product in its actual life cycle conditions to determine the advent of failure and mitigate system risk. Sensor systems are needed for PHM to monitor environmental, operational, and performance-related characteristics. The gathered data can be analyzed to assess product health and predict remaining life. In this paper, the considerations for sensor system selection for PHM applications, including the parameters to be measured, the performance needs, the electrical and physical attributes, reliability, and cost of the sensor system, are discussed. The state-of-the-art sensor systems for PHM and the emerging trends in technologies of sensor systems for PHM are presented. PMID:22219686

Preliminary investigations of active pixel sensors in Nuclear Medicine imaging

NASA Astrophysics Data System (ADS)

Ott, Robert; Evans, Noel; Evans, Phil; Osmond, J.; Clark, A.; Turchetta, R.

2009-06-01

Three CMOS active pixel sensors have been investigated for their application to Nuclear Medicine imaging. Startracker with 525×525 25 μm square pixels has been coupled via a fibre optic stud to a 2 mm thick segmented CsI(Tl) crystal. Imaging tests were performed using 99mTc sources, which emit 140 keV gamma rays. The system was interfaced to a PC via FPGA-based DAQ and optical link enabling imaging rates of 10 f/s. System noise was measured to be >100e and it was shown that the majority of this noise was fixed pattern in nature. The intrinsic spatial resolution was measured to be ˜80 μm and the system spatial resolution measured with a slit was ˜450 μm. The second sensor, On Pixel Intelligent CMOS (OPIC), had 64×72 40 μm pixels and was used to evaluate noise characteristics and to develop a method of differentiation between fixed pattern and statistical noise. The third sensor, Vanilla, had 520×520 25 μm pixels and a measured system noise of ˜25e. This sensor was coupled directly to the segmented phosphor. Imaging results show that even at this lower level of noise the signal from 140 keV gamma rays is small as the light from the phosphor is spread over a large number of pixels. Suggestions for the 'ideal' sensor are made.

Sensor-guided threat countermeasure system

DOEpatents

Stuart, Brent C.; Hackel, Lloyd A.; Hermann, Mark R.; Armstrong, James P.

2012-12-25

A countermeasure system for use by a target to protect against an incoming sensor-guided threat. The system includes a laser system for producing a broadband beam and means for directing the broadband beam from the target to the threat. The countermeasure system comprises the steps of producing a broadband beam and directing the broad band beam from the target to blind or confuse the incoming sensor-guided threat.

An efficient management system for wireless sensor networks.

PubMed

Ma, Yi-Wei; Chen, Jiann-Liang; Huang, Yueh-Min; Lee, Mei-Yu

2010-01-01

Wireless sensor networks have garnered considerable attention recently. Networks typically have many sensor nodes, and are used in commercial, medical, scientific, and military applications for sensing and monitoring the physical world. Many researchers have attempted to improve wireless sensor network management efficiency. A Simple Network Management Protocol (SNMP)-based sensor network management system was developed that is a convenient and effective way for managers to monitor and control sensor network operations. This paper proposes a novel WSNManagement system that can show the connections stated of relationships among sensor nodes and can be used for monitoring, collecting, and analyzing information obtained by wireless sensor networks. The proposed network management system uses collected information for system configuration. The function of performance analysis facilitates convenient management of sensors. Experimental results show that the proposed method enhances the alive rate of an overall sensor node system, reduces the packet lost rate by roughly 5%, and reduces delay time by roughly 0.2 seconds. Performance analysis demonstrates that the proposed system is effective for wireless sensor network management.

Sensor system for web inspection

DOEpatents

Sleefe, Gerard E.; Rudnick, Thomas J.; Novak, James L.

2002-01-01

A system for electrically measuring variations over a flexible web has a capacitive sensor including spaced electrically conductive, transmit and receive electrodes mounted on a flexible substrate. The sensor is held against a flexible web with sufficient force to deflect the path of the web, which moves relative to the sensor.

Application of activity sensors for estimating behavioral patterns

USGS Publications Warehouse

Roberts, Caleb P.; Cain, James W.; Cox, Robert D.

2016-01-01

The increasing use of Global Positioning System (GPS) collars in habitat selection studies provides large numbers of precise location data points with reduced field effort. However, inclusion of activity sensors in many GPS collars also grants the potential to remotely estimate behavioral state. Thus, only using GPS collars to collect location data belies their full capabilities. Coupling behavioral state with location data would allow researchers and managers to refine habitat selection models by using diel behavioral state changes to partition fine-scale temporal shifts in habitat selection. We tested the capability of relatively unsophisticated GPS-collar activity sensors to estimate behavior throughout diel periods using free-ranging female elk (Cervus canadensis) in the Jemez Mountains of north-central New Mexico, USA, 2013–2014. Collars recorded cumulative number of movements (hits) per 15-min recording period immediately preceding GPS fixes at 0000, 0600, 1200, and 1800 hr. We measured diel behavioral patterns of focal elk, categorizing active (i.e., foraging, traveling, vigilant, grooming) and inactive (i.e., resting) states. Active behaviors (foraging, traveling) produced more average hits (0.87 ± 0.69 hits/min, 4.0 ± 2.2 hits/min, respectively; 95% CI) and inactive (resting) behavior fewer hits (−1.1 ± 0.61 95% CI). We differentiated active and inactive behavioral states with a bootstrapped threshold of 5.9 ± 3.9 hits/15-min recording period. Mean cumulative activity-sensor hits corresponded with observed diel behavioral patterns: hits increased during crepuscular (0600, 1800 hr) observations when elk were most active (0000–0600 hr: d = 0.19; 1200–1800 hr: d = 0.64) and decreased during midday and night (0000 hr, 1200 hr) when elk were least active (1800–0000 hr: d = −0.39; 0600–1200 hr: d = −0.43). Even using relatively unsophisticated GPS-collar activity sensors, managers can

Magnetic force driven six degree-of-freedom active vibration isolation system using a phase compensated velocity sensor.

PubMed

Kim, Yongdae; Kim, Sangyoo; Park, Kyihwan

2009-04-01

A six-axis active vibration isolation system (AVIS) is developed using voice coil actuators. Point contact configuration is employed to have an easy assembly of eight voice coil actuators to an upper and a base plates. The velocity sensor, using an electromagnetic principle that is commonly used in the vibration control, is investigated since its phase lead characteristic causes an instability problem for a low frequency vibration. The performances of the AVIS are investigated in the frequency domain and finally validated by comparing with the passive isolation system using the atomic force microscope images.

Surface-Electrochemical Sensor for the Measurement of Anti-Cholinesterase Activity

NASA Astrophysics Data System (ADS)

Matsuura, Hiroaki; Sato, Yukari; Yabuki, Soichi; Sawaguchi, Takahiro; Mizutani, Fumio

An organophosphorus pesticide, ethylthiometon (0.01-0.2 ppm) was determined by using a surface-electrochemical sensor system: the monolayer formation (chemisorption)-reductive desorption of thiocholine was applied to monitor the activity change of cholinesterase caused by the pesticide.

Monolithic Active Pixel Sensors

NASA Astrophysics Data System (ADS)

Lutz, P.

In close collaboration with the group from Strasbourg, Saclay has been developing fast monolithic active pixel sensors for future vertex detectors. This presentation gives some recent results from the MIMOSA serie, emphazising the participation of the group.

High-power fiber optic cable with integrated active sensors for live process monitoring

NASA Astrophysics Data System (ADS)

Blomster, Ola; Blomqvist, Mats; Bergstrand, Hans; Pålsson, Magnus

2012-03-01

In industrial applications using high-brilliance lasers at power levels up to and exceeding 20 kW and similarly direct diode lasers of 10 kW, there is an increasing demand to continuously monitor component status even in passive components such as fiber-optic cables. With fiber-optic cables designed according to the European Automotive Industry fiber standard interface there is room for integrating active sensors inside the connectors. In this paper we present the integrated active sensors in the new Optoskand QD fiber-optic cable designed to handle extreme levels of power losses, and how these sensors can be employed in industrial manufacturing. The sensors include photo diodes for detection of scattered light inside the fiber connector, absolute temperature of the fiber connector, difference in temperature of incoming and outgoing cooling water, and humidity measurement inside the fiber connector. All these sensors are connected to the fiber interlock system, where interlock break enable functions can be activated when measured signals are higher than threshold levels. It is a very fast interlock break system as the control of the signals is integrated in the electronics inside the fiber connector. Also, since all signals can be logged it is possible to evaluate what happened inside the connector before the interlock break instance. The communication to the fiber-optic connectors is via a CAN interface. Thus it is straightforward to develop the existing laser host control to also control the CAN-messages from the QD sensors.

Intelligence Control System for Landfills Based on Wireless Sensor Network

NASA Astrophysics Data System (ADS)

Zhang, Qian; Huang, Chuan; Gong, Jian

2018-06-01

This paper put forward an intelligence system for controlling the landfill gas in landfills to make the landfill gas (LFG) exhaust controllably and actively. The system, which is assigned by the wireless sensor network, were developed and supervised by remote applications in workshop instead of manual work. An automatic valve control depending on the sensor units embedded is installed in tube, the air pressure and concentration of LFG are detected to decide the level of the valve switch. The paper also proposed a modified algorithm to solve transmission problem, so that the system can keep a high efficiency and long service life.

Toward seamless wearable sensing: Automatic on-body sensor localization for physical activity monitoring.

PubMed

Saeedi, Ramyar; Purath, Janet; Venkatasubramanian, Krishna; Ghasemzadeh, Hassan

2014-01-01

Mobile wearable sensors have demonstrated great potential in a broad range of applications in healthcare and wellness. These technologies are known for their potential to revolutionize the way next generation medical services are supplied and consumed by providing more effective interventions, improving health outcomes, and substantially reducing healthcare costs. Despite these potentials, utilization of these sensor devices is currently limited to lab settings and in highly controlled clinical trials. A major obstacle in widespread utilization of these systems is that the sensors need to be used in predefined locations on the body in order to provide accurate outcomes such as type of physical activity performed by the user. This has reduced users' willingness to utilize such technologies. In this paper, we propose a novel signal processing approach that leverages feature selection algorithms for accurate and automatic localization of wearable sensors. Our results based on real data collected using wearable motion sensors demonstrate that the proposed approach can perform sensor localization with 98.4% accuracy which is 30.7% more accurate than an approach without a feature selection mechanism. Furthermore, utilizing our node localization algorithm aids the activity recognition algorithm to achieve 98.8% accuracy (an increase from 33.6% for the system without node localization).

Pulse-driven magnetoimpedance sensor detection of cardiac magnetic activity.

PubMed

Nakayama, Shinsuke; Sawamura, Kenta; Mohri, Kaneo; Uchiyama, Tsuyoshi

2011-01-01

This study sought to establish a convenient method for detecting biomagnetic activity in the heart. Electrical activity of the heart simultaneously induces a magnetic field. Detection of this magnetic activity will enable non-contact, noninvasive evaluation to be made. We improved the sensitivity of a pulse-driven magnetoimpedance (PMI) sensor, which is used as an electric compass in mobile phones and as a motion sensor of the operation handle in computer games, toward a pico-Tesla (pT) level, and measured magnetic fields on the surface of the thoracic wall in humans. The changes in magnetic field detected by this sensor synchronized with the electric activity of the electrocardiogram (ECG). The shape of the magnetic wave was largely altered by shifting the sensor position within 20 mm in parallel and/or perpendicular to the thoracic wall. The magnetic activity was maximal in the 4th intercostals near the center of the sterna. Furthermore, averaging the magnetic activity at 15 mm in the distance between the thoracic wall and the sensor demonstrated magnetic waves mimicking the P wave and QRS complex. The present study shows the application of PMI sensor in detecting cardiac magnetic activity in several healthy subjects, and suggests future applications of this technology in medicine and biology.

Evaluation of FNS control systems: software development and sensor characterization.

PubMed

Riess, J; Abbas, J J

1997-01-01

Functional Neuromuscular Stimulation (FNS) systems activate paralyzed limbs by electrically stimulating motor neurons. These systems have been used to restore functions such as standing and stepping in people with thoracic level spinal cord injury. Research in our laboratory is directed at the design and evaluation of the control algorithms for generating posture and movement. This paper describes software developed for implementing FNS control systems and the characterization of a sensor system used to implement and evaluate controllers in the laboratory. In order to assess FNS control algorithms, we have developed a versatile software package using Lab VIEW (National Instruments, Corp). This package provides the ability to interface with sensor systems via serial port or A/D board, implement data processing and real-time control algorithms, and interface with neuromuscular stimulation devices. In our laboratory, we use the Flock of Birds (Ascension Technology Corp.) motion tracking sensor system to monitor limb segment position and orientation (6 degrees of freedom). Errors in the sensor system have been characterized and nonlinear polynomial models have been developed to account for these errors. With this compensation, the error in the distance measurement is reduced by 90 % so that the maximum error is less than 1 cm.

A CMOS active pixel sensor for retinal stimulation

NASA Astrophysics Data System (ADS)

Prydderch, Mark L.; French, Marcus J.; Mathieson, Keith; Adams, Christopher; Gunning, Deborah; Laudanski, Jonathan; Morrison, James D.; Moodie, Alan R.; Sinclair, James

2006-02-01

Degenerative photoreceptor diseases, such as age-related macular degeneration and retinitis pigmentosa, are the most common causes of blindness in the western world. A potential cure is to use a microelectronic retinal prosthesis to provide electrical stimulation to the remaining healthy retinal cells. We describe a prototype CMOS Active Pixel Sensor capable of detecting a visual scene and translating it into a train of electrical pulses for stimulation of the retina. The sensor consists of a 10 x 10 array of 100 micron square pixels fabricated on a 0.35 micron CMOS process. Light incident upon each pixel is converted into output current pulse trains with a frequency related to the light intensity. These outputs are connected to a biocompatible microelectrode array for contact to the retinal cells. The flexible design allows experimentation with signal amplitudes and frequencies in order to determine the most appropriate stimulus for the retina. Neural processing in the retina can be studied by using the sensor in conjunction with a Field Programmable Gate Array (FPGA) programmed to behave as a neural network. The sensor has been integrated into a test system designed for studying retinal response. We present the most recent results obtained from this sensor.

Handheld chemiresistive gas sensor readout system

NASA Astrophysics Data System (ADS)

Joubert, Trudi-Heleen; du Toit, Jurie; Mkwakikunga, Bonex; Bosscha, Peter

2016-02-01

Low-cost and non-invasive diabetes diagnosis is increasingly important [1], and this paper presents a handheld readout system for chemiresistive gas sensors in a breath acetone diagnostic application. The sensor contains reference and detection devices, used for the detection of gas concentration. Fabrication is by dropcasting a metaloxide nanowire solution onto gold interdigitated electrodes, which had been manufactured on silicon. The resulting layer is a wide bandgap n-type semiconductor material sensitive to acetone, producing a change in resistance between the electrode terminals [2]. Chemiresistive sensors typically require temperatures of 300-500 °C, while variation of sensing temperature is also employed for selective gas detection. The nano-structured functional material requires low temperatures due to large surface area, but heating is still required for acceptable recovery kinetics. Furthermore, UV illumination improves the sensor recovery [3], and is implemented in this system. Sensor resistances range from 100 Ω to 50 MΩ, while the sensor response time require a sampling frequency of 10Hz. Sensor resistance depends on temperature, humidity, and barometric pressure. The GE CC2A23 temperature sensor is used over a range of -10°C to 60°C, the Honeywell HIH5031 humidity sensor operates up to 85% over this temperature range, and the LPS331AP barometric pressure sensor measures up to 1.25 bar. Honeywell AWM43300V air flow sensors monitor the flow rate up to 1000 sccm. An LCD screen displays all the sensor data, as well as real time date and time, while all measurements are also logged in CSV-format. The system operates from a rechargeable battery.

Improved thermal neutron activation sensor for detection of bulk explosives

NASA Astrophysics Data System (ADS)

McFee, John E.; Faust, Anthony A.; Andrews, H. Robert; Clifford, Edward T. H.; Mosquera, Cristian M.

2012-06-01

Defence R&D Canada - Suffield and Bubble Technology Industries have been developing thermal neutron activation (TNA) sensors for detection of buried bulk explosives since 1994. First generation sensors, employing an isotopic source and NaI(Tl) gamma ray detectors, were deployed by Canadian Forces in 2002 as confirmation sensors on the ILDS teleoperated, vehicle-mounted, multi-sensor anti-tank landmine detection systems. The first generation TNA could detect anti-tank mines buried 10 cm or less in no more than a minute, but deeper mines and those significantly displaced horizontally required considerably longer times. Mines as deep as 30 cm could be detected with long counting times (1000 s). The second generation TNA detector is being developed with a number of improvements aimed at increasing sensitivity and facilitating ease of operation. Among these are an electronic neutron generator to increase sensitivity for deeper and horizontally displaced explosives; LaBr3(Ce) scintillators, to improve time response and energy resolution; improved thermal and electronic stability; improved sensor head geometry to minimize spatial response nonuniformity; and more robust data processing. This improved sensitivity can translate to either decreased counting times, decreased minimum detectable explosive quantities, increased maximum sensor-to-target displacement, or a trade off among all three. Experiments to characterize the performance of the latest generation TNA in detecting buried landmines and IEDs hidden in culverts were conducted during 2011. This paper describes the second generation system. The experimental setup and methodology are detailed and preliminary comparisons between the performance of first and second generation systems are presented.

Global Positioning System Synchronized Active Light Autonomous Docking System

NASA Technical Reports Server (NTRS)

Howard, Richard T. (Inventor); Book, Michael L. (Inventor); Bryan, Thomas C. (Inventor); Bell, Joseph L. (Inventor)

1996-01-01

A Global Positioning System Synchronized Active Light Autonomous Docking System (GPSSALADS) for automatically docking a chase vehicle with a target vehicle comprising at least one active light emitting target which is operatively attached to the target vehicle. The target includes a three-dimensional array of concomitantly flashing lights which flash at a controlled common frequency. The GPSSALADS further comprises a visual tracking sensor operatively attached to the chase vehicle for detecting and tracking the target vehicle. Its performance is synchronized with the flash frequency of the lights by a synchronization means which is comprised of first and second internal clocks operatively connected to the active light target and visual tracking sensor, respectively, for providing timing control signals thereto, respectively. The synchronization means further includes first and second Global Positioning System receivers operatively connected to the first and second internal clocks, respectively, for repeatedly providing simultaneous synchronization pulses to the internal clocks, respectively. In addition, the GPSSALADS includes a docking process controller means which is operatively attached to the chase vehicle and is responsive to the visual tracking sensor for producing commands for the guidance and propulsion system of the chase vehicle.

Global Positioning System Synchronized Active Light Autonomous Docking System

NASA Technical Reports Server (NTRS)

Howard, Richard (Inventor)

1994-01-01

A Global Positioning System Synchronized Active Light Autonomous Docking System (GPSSALADS) for automatically docking a chase vehicle with a target vehicle comprises at least one active light emitting target which is operatively attached to the target vehicle. The target includes a three-dimensional array of concomitantly flashing lights which flash at a controlled common frequency. The GPSSALADS further comprises a visual tracking sensor operatively attached to the chase vehicle for detecting and tracking the target vehicle. Its performance is synchronized with the flash frequency of the lights by a synchronization means which is comprised of first and second internal clocks operatively connected to the active light target and visual tracking sensor, respectively, for providing timing control signals thereto, respectively. The synchronization means further includes first and second Global Positioning System receivers operatively connected to the first and second internal clocks, respectively, for repeatedly providing simultaneous synchronization pulses to the internal clocks, respectively. In addition, the GPSSALADS includes a docking process controller means which is operatively attached to the chase vehicle and is responsive to the visual tracking sensor for producing commands for the guidance and propulsion system of the chase vehicle.

Structural health monitoring system for bridges based on skin-like sensor

NASA Astrophysics Data System (ADS)

Loupos, Konstantinos; Damigos, Yannis; Amditis, Angelos; Gerhard, Reimund; Rychkov, Dmitry; Wirges, Werner; Schulze, Manuel; Lenas, Sotiris-Angelos; Chatziandreoglou, Christos; Malliou, Christina M.; Tsaoussidis, Vassilis; Brady, Ken; Frankenstein, Bernd

2017-09-01

Structural health monitoring activities are of primal importance for managing transport infrastructure, however most SHM methodologies are based on point-based sensors that have limitations in terms of their spatial positioning requirements, cost of development and measurement range. This paper describes the progress on the SENSKIN EC project whose objective is to develop a dielectric-elastomer and micro-electronics-based sensor, formed from a large highly extensible capacitance sensing membrane supported by advanced microelectronic circuitry, for monitoring transport infrastructure bridges. Such a sensor could provide spatial measurements of strain in excess of 10%. The actual sensor along with the data acquisition module, the communication module and power electronics are all integrated into a compact unit, the SENSKIN device, which is energy-efficient, requires simple signal processing and it is easy to install over various surface types. In terms of communication, SENSKIN devices interact with each other to form the SENSKIN system; a fully distributed and autonomous wireless sensor network that is able to self-monitor. SENSKIN system utilizes Delay-/Disruption-Tolerant Networking technologies to ensure that the strain measurements will be received by the base station even under extreme conditions where normal communications are disrupted. This paper describes the architecture of the SENSKIN system and the development and testing of the first SENSKIN prototype sensor, the data acquisition system, and the communication system.

Integration of OLEDs in biomedical sensor systems: design and feasibility analysis

NASA Astrophysics Data System (ADS)

Rai, Pratyush; Kumar, Prashanth S.; Varadan, Vijay K.

2010-04-01

Organic (electronic) Light Emitting Diodes (OLEDs) have been shown to have applications in the field of lighting and flexible display. These devices can also be incorporated in sensors as light source for imaging/fluorescence sensing for miniaturized systems for biomedical applications and low-cost displays for sensor output. The current device capability aligns well with the aforementioned applications as low power diffuse lighting and momentary/push button dynamic display. A top emission OLED design has been proposed that can be incorporated with the sensor and peripheral electrical circuitry, also based on organic electronics. Feasibility analysis is carried out for an integrated optical imaging/sensor system, based on luminosity and spectrum band width. A similar study is also carried out for sensor output display system that functions as a pseudo active OLED matrix. A power model is presented for device power requirements and constraints. The feasibility analysis is also supplemented with the discussion about implementation of ink-jet printing and stamping techniques for possibility of roll to roll manufacturing.

Optical fiber sensors: Systems and applications. Volume 2

NASA Astrophysics Data System (ADS)

Culshaw, Brian; Dakin, John

State-of-the-art fiber-optic (FO) sensors and their applications are described in chapters contributed by leading experts. Consideration is given to interferometers, FO gyros, intensity- and wavelength-based sensors and optical actuators, Si in FO sensors, point-sensor multiplexing principles, and distributed FO sensor systems. Also examined are chemical, biochemical, and medical sensors; physical and chemical sensors for process control; FO-sensor applications in the marine and aerospace industries; FO-sensor monitoring systems for security and safety, structural integrity, NDE, and the electric-power industry; and the market situation for FO-sensor technology. Diagrams, drawings, graphs, and photographs are provided.

New virtual sonar and wireless sensor system concepts

NASA Astrophysics Data System (ADS)

Houston, B. H.; Bucaro, J. A.; Romano, A. J.

2004-05-01

Recently, exciting new sensor array concepts have been proposed which, if realized, could revolutionize how we approach surface mounted acoustic sensor systems for underwater vehicles. Two such schemes are so-called ``virtual sonar'' which is formulated around Helmholtz integral processing and ``wireless'' systems which transfer sensor information through radiated RF signals. The ``virtual sonar'' concept provides an interesting framework through which to combat the dilatory effects of the structure on surface mounted sensor systems including structure-borne vibration and variations in structure-backing impedance. The ``wireless'' concept would eliminate the necessity of a complex wiring or fiber-optic external network while minimizing vehicle penetrations. Such systems, however, would require a number of advances in sensor and RF waveguide technologies. In this presentation, we will discuss those sensor and sensor-related developments which are desired or required in order to make practical such new sensor system concepts, and we will present several underwater applications from the perspective of exploiting these new sonar concepts. [Work supported by ONR.

Investigations on the influence of breathing on brain activity using optical sensors

NASA Astrophysics Data System (ADS)

Rao, Mandavilli M.; Blazek, Vladimir; Schmitt, Hans J.

1997-05-01

In recent years investigation and understanding of the brain activity is receiving much attention. Such investigations are generally confined to few select premier research institutions where expensive and sophisticated facilities like EEG, PET, FMRI, etc. are available. Of late optical sensors are receiving much attention for biomedical applications because they are relatively simple in construction, easy to use and comparatively inexpensive. Among the biomedical optical sensors, photophlethysmographic (PPG) measuring systems have a unique position. They function as transcutaneous registration of blood volume changes in the near skin blood vessels. By recording the signals from the supply to the left and right lobes of the brain in the cerebral cortex. The oxygen content in the arterary blood flow to the brain will naturally have an important role to play in the activity of the brain. It is suggested that by positioning sensitive temperature sensors in the nostrils of a subject, one could monitor his breathing activity. By recording the outputs rom these temperature sensor for several hours, it has been noticed that the breathing activity of a subject will change from one nostril to another periodically. Besides, it has also been observed that any sudden fluctuations in the breathing pattern is accompanied by changes in the blood flow to the brain as monitored by PPG optical sensors mounted on the temples of a subject. An attempt is made to understand such events.

Concept of electro-optical sensor module for sniper detection system

NASA Astrophysics Data System (ADS)

Trzaskawka, Piotr; Dulski, Rafal; Kastek, Mariusz

2010-10-01

The paper presents an initial concept of the electro-optical sensor unit for sniper detection purposes. This unit, comprising of thermal and daylight cameras, can operate as a standalone device but its primary application is a multi-sensor sniper and shot detection system. Being a part of a larger system it should contribute to greater overall system efficiency and lower false alarm rate thanks to data and sensor fusion techniques. Additionally, it is expected to provide some pre-shot detection capabilities. Generally acoustic (or radar) systems used for shot detection offer only "after-the-shot" information and they cannot prevent enemy attack, which in case of a skilled sniper opponent usually means trouble. The passive imaging sensors presented in this paper, together with active systems detecting pointed optics, are capable of detecting specific shooter signatures or at least the presence of suspected objects in the vicinity. The proposed sensor unit use thermal camera as a primary sniper and shot detection tool. The basic camera parameters such as focal plane array size and type, focal length and aperture were chosen on the basis of assumed tactical characteristics of the system (mainly detection range) and current technology level. In order to provide costeffective solution the commercially available daylight camera modules and infrared focal plane arrays were tested, including fast cooled infrared array modules capable of 1000 fps image acquisition rate. The daylight camera operates as a support, providing corresponding visual image, easier to comprehend for a human operator. The initial assumptions concerning sensor operation were verified during laboratory and field test and some example shot recording sequences are presented.

Electric-field sensors for bullet detection systems

NASA Astrophysics Data System (ADS)

Vinci, Stephen; Hull, David; Ghionea, Simon; Ludwig, William; Deligeorges, Socrates; Gudmundsson, Thorkell; Noras, Maciej

2014-06-01

Research and experimental trials have shown that electric-field (E-field) sensors are effective at detecting charged projectiles. E-field sensors can likely complement traditional acoustic sensors, and help provide a more robust and effective solution for bullet detection and tracking. By far, the acoustic sensor is the most prevalent technology in use today for hostile fire defeat systems due to compact size and low cost, yet they come with a number of challenges that include multipath, reverberant environments, false positives and low signal-to-noise. Studies have shown that these systems can benefit from additional sensor modalities such as E-field sensors. However, E-field sensors are a newer technology that is relatively untested beyond basic experimental trials; this technology has not been deployed in any fielded systems. The U.S. Army Research Laboratory (ARL) has conducted live-fire experiments at Aberdeen Proving Grounds (APG) to collect data from E-field sensors. Three types of E-field sensors were included in these experiments: (a) an electric potential gradiometer manufactured by Quasar Federal Systems (QFS), (b) electric charge induction, or "D-dot" sensors designed and built by the Army Research Lab (ARL), and (c) a varactor based E-field sensor prototype designed by University of North Carolina-Charlotte (UNCC). Sensors were placed in strategic locations near the bullet trajectories, and their data were recorded. We analyzed the performance of each E-field sensor type in regard to small-arms bullet detection capability. The most recent experiment in October 2013 allowed demonstration of improved versions of the varactor and D-dot sensor types. Results of new real-time analysis hardware employing detection algorithms were also tested. The algorithms were used to process the raw data streams to determine when bullet detections occurred. Performance among the sensor types and algorithm effectiveness were compared to estimates from acoustics signatures

Active Temperature Compensation Using a High-Temperature, Fiber Optic, Hybrid Pressure and Temperature Sensor

NASA Astrophysics Data System (ADS)

Fielder, Robert S.; Palmer, Matthew E.; Davis, Matthew A.; Engelbrecht, Gordon P.

2006-01-01

Luna Innovations has developed a novel, fiber optic, hybrid pressure-temperature sensor system for extremely high-temperature environments that is capable of reliable operation up to 1050 °C. This system is based on the extremely high-temperature fiber optic sensors already demonstrated during previous work. The novelty of the sensors presented here lies in the fact that pressure and temperature are measured simultaneously with a single fiber and a single transducer. This hybrid approach will enable highly accurate active temperature compensation and sensor self-diagnostics not possible with other platforms. Hybrid pressure and temperature sensors were calibrated by varying both pressure and temperature. Implementing active temperature compensation resulted in a ten-fold reduction in the temperature-dependence of the pressure measurement. Sensors were tested for operability in a relatively high neutron dose environment up to 6.9×1017 n/cm2. In addition to harsh environment survivability, fiber optic sensors offer a number of intrinsic advantages for space nuclear power applications including extremely low mass, immunity to electromagnetic interference, self diagnostics / prognostics, and smart sensor capability. Deploying fiber optic sensors on future space exploration missions would provide a substantial improvement in spacecraft instrumentation. Additional development is needed, however, before these advantages can be realized. This paper will highlight recent demonstrations of fiber optic sensors in environments relevant to space nuclear applications. Successes and lessons learned will be highlighted. Additionally, development needs will be covered which will suggest a framework for a coherent plan to continue work in this area.

Multi-sensor calibration of low-cost magnetic, angular rate and gravity systems.

PubMed

Lüken, Markus; Misgeld, Berno J E; Rüschen, Daniel; Leonhardt, Steffen

2015-10-13

We present a new calibration procedure for low-cost nine degrees-of-freedom (9DOF) magnetic, angular rate and gravity (MARG) sensor systems, which relies on a calibration cube, a reference table and a body sensor network (BSN). The 9DOF MARG sensor is part of our recently-developed "Integrated Posture and Activity Network by Medit Aachen" (IPANEMA) BSN. The advantage of this new approach is the use of the calibration cube, which allows for easy integration of two sensor nodes of the IPANEMA BSN. One 9DOF MARG sensor node is thereby used for calibration; the second 9DOF MARG sensor node is used for reference measurements. A novel algorithm uses these measurements to further improve the performance of the calibration procedure by processing arbitrarily-executed motions. In addition, the calibration routine can be used in an alignment procedure to minimize errors in the orientation between the 9DOF MARG sensor system and a motion capture inertial reference system. A two-stage experimental study is conducted to underline the performance of our calibration procedure. In both stages of the proposed calibration procedure, the BSN data, as well as reference tracking data are recorded. In the first stage, the mean values of all sensor outputs are determined as the absolute measurement offset to minimize integration errors in the derived movement model of the corresponding body segment. The second stage deals with the dynamic characteristics of the measurement system where the dynamic deviation of the sensor output compared to a reference system is Sensors 2015, 15 25920 corrected. In practical validation experiments, this procedure showed promising results with a maximum RMS error of 3.89°.

Sensors 2000! Program: Advanced Biosensor and Measurement Systems Technologies for Spaceflight Research and Concurrent, Earth-Based Applications

NASA Technical Reports Server (NTRS)

Hines, J.

1999-01-01

Sensors 2000! (S2K!) is a specialized, integrated projects team organized to provide focused, directed, advanced biosensor and bioinstrumentation systems technology support to NASA's spaceflight and ground-based research and development programs. Specific technology thrusts include telemetry-based sensor systems, chemical/ biological sensors, medical and physiological sensors, miniaturized instrumentation architectures, and data and signal processing systems. A concurrent objective is to promote the mutual use, application, and transition of developed technology by collaborating in academic-commercial-govemment leveraging, joint research, technology utilization and commercialization, and strategic partnering alliances. Sensors 2000! is organized around three primary program elements: Technology and Product Development, Technology infusion and Applications, and Collaborative Activities. Technology and Product Development involves development and demonstration of biosensor and biotelemetry systems for application to NASA Space Life Sciences Programs; production of fully certified spaceflight hardware and payload elements; and sensor/measurement systems development for NASA research and development activities. Technology Infusion and Applications provides technology and program agent support to identify available and applicable technologies from multiple sources for insertion into NASA's strategic enterprises and initiatives. Collaborative Activities involve leveraging of NASA technologies with those of other government agencies, academia, and industry to concurrently provide technology solutions and products of mutual benefit to participating members.

The Radio Frequency Health Node Wireless Sensor System

NASA Technical Reports Server (NTRS)

Valencia, J. Emilio; Stanley, Priscilla C.; Mackey, Paul J.

2009-01-01

The Radio Frequency Health Node (RFHN) wireless sensor system differs from other wireless sensor systems in ways originally intended to enhance utility as an instrumentation system for a spacecraft. The RFHN can also be adapted to use in terrestrial applications in which there are requirements for operational flexibility and integrability into higher-level instrumentation and data acquisition systems. As shown in the figure, the heart of the system is the RFHN, which is a unit that passes commands and data between (1) one or more commercially available wireless sensor units (optionally, also including wired sensor units) and (2) command and data interfaces with a local control computer that may be part of the spacecraft or other engineering system in which the wireless sensor system is installed. In turn, the local control computer can be in radio or wire communication with a remote control computer that may be part of a higher-level system. The remote control computer, acting via the local control computer and the RFHN, cannot only monitor readout data from the sensor units but can also remotely configure (program or reprogram) the RFHN and the sensor units during operation. In a spacecraft application, the RFHN and the sensor units can also be configured more nearly directly, prior to launch, via a serial interface that includes an umbilical cable between the spacecraft and ground support equipment. In either case, the RFHN wireless sensor system has the flexibility to be configured, as required, with different numbers and types of sensors for different applications. The RFHN can be used to effect realtime transfer of data from, and commands to, the wireless sensor units. It can also store data for later retrieval by an external computer. The RFHN communicates with the wireless sensor units via a radio transceiver module. The modular design of the RFHN makes it possible to add radio transceiver modules as needed to accommodate additional sets of wireless sensor

Active Self-Testing Noise Measurement Sensors for Large-Scale Environmental Sensor Networks

PubMed Central

Domínguez, Federico; Cuong, Nguyen The; Reinoso, Felipe; Touhafi, Abdellah; Steenhaut, Kris

2013-01-01

Large-scale noise pollution sensor networks consist of hundreds of spatially distributed microphones that measure environmental noise. These networks provide historical and real-time environmental data to citizens and decision makers and are therefore a key technology to steer environmental policy. However, the high cost of certified environmental microphone sensors render large-scale environmental networks prohibitively expensive. Several environmental network projects have started using off-the-shelf low-cost microphone sensors to reduce their costs, but these sensors have higher failure rates and produce lower quality data. To offset this disadvantage, we developed a low-cost noise sensor that actively checks its condition and indirectly the integrity of the data it produces. The main design concept is to embed a 13 mm speaker in the noise sensor casing and, by regularly scheduling a frequency sweep, estimate the evolution of the microphone's frequency response over time. This paper presents our noise sensor's hardware and software design together with the results of a test deployment in a large-scale environmental network in Belgium. Our middle-range-value sensor (around €50) effectively detected all experienced malfunctions, in laboratory tests and outdoor deployments, with a few false positives. Future improvements could further lower the cost of our sensor below €10. PMID:24351634

Optical Breath Gas Extravehicular Activity Sensor for the Advanced Portable Life Support System

NASA Technical Reports Server (NTRS)

Wood, William R.; Casias, Miguel E.; Pilgrim, Jeffrey S.; Chullen, Cinda; Campbell, Colin

2016-01-01

The infrared gas transducer used during extravehicular activity (EVA) in the extravehicular mobility unit (EMU) measures and reports the concentration of carbon dioxide (CO2) in the ventilation loop. It is nearing its end of life and there are a limited number remaining. Meanwhile, the next generation advanced portable life support system (PLSS) now being developed requires CO2 sensing technology with performance beyond that presently in use. A laser diode (LD) spectrometer based on wavelength modulation spectroscopy (WMS) is being developed to address both applications by Vista Photonics, Inc. Accommodation within space suits demands that optical sensors meet stringent size, weight, and power requirements. Version 1.0 devices were delivered to NASA Johnson Space Center (JSC) in 2011. The sensors incorporate a laser diode based CO2 channel that also includes an incidental water vapor (humidity) measurement. The prototypes are controlled digitally with a field-programmable gate array (FPGA)/microcontroller architecture. Version 2.0 devices with improved electronics and significantly reduced wetted volumes were delivered to JSC in 2012. A version 2.5 upgrade recently implemented wavelength stabilized operation, better humidity measurement, and much faster data analysis/reporting. A wholly reconfigured version 3.0 will maintain the demonstrated performance of earlier versions while being backwards compatible with the EMU and offering a radiation tolerant architecture.

Sensor Technologies for Intelligent Transportation Systems

PubMed Central

Guerrero-Ibáñez, Juan; Zeadally, Sherali

2018-01-01

Modern society faces serious problems with transportation systems, including but not limited to traffic congestion, safety, and pollution. Information communication technologies have gained increasing attention and importance in modern transportation systems. Automotive manufacturers are developing in-vehicle sensors and their applications in different areas including safety, traffic management, and infotainment. Government institutions are implementing roadside infrastructures such as cameras and sensors to collect data about environmental and traffic conditions. By seamlessly integrating vehicles and sensing devices, their sensing and communication capabilities can be leveraged to achieve smart and intelligent transportation systems. We discuss how sensor technology can be integrated with the transportation infrastructure to achieve a sustainable Intelligent Transportation System (ITS) and how safety, traffic control and infotainment applications can benefit from multiple sensors deployed in different elements of an ITS. Finally, we discuss some of the challenges that need to be addressed to enable a fully operational and cooperative ITS environment. PMID:29659524

Sensor Technologies for Intelligent Transportation Systems.

PubMed

Guerrero-Ibáñez, Juan; Zeadally, Sherali; Contreras-Castillo, Juan

2018-04-16

Modern society faces serious problems with transportation systems, including but not limited to traffic congestion, safety, and pollution. Information communication technologies have gained increasing attention and importance in modern transportation systems. Automotive manufacturers are developing in-vehicle sensors and their applications in different areas including safety, traffic management, and infotainment. Government institutions are implementing roadside infrastructures such as cameras and sensors to collect data about environmental and traffic conditions. By seamlessly integrating vehicles and sensing devices, their sensing and communication capabilities can be leveraged to achieve smart and intelligent transportation systems. We discuss how sensor technology can be integrated with the transportation infrastructure to achieve a sustainable Intelligent Transportation System (ITS) and how safety, traffic control and infotainment applications can benefit from multiple sensors deployed in different elements of an ITS. Finally, we discuss some of the challenges that need to be addressed to enable a fully operational and cooperative ITS environment.

Phase discriminating capacitive array sensor system

NASA Technical Reports Server (NTRS)

Vranish, John M. (Inventor); Rahim, Wadi (Inventor)

1993-01-01

A phase discriminating capacitive sensor array system which provides multiple sensor elements which are maintained at a phase and amplitude based on a frequency reference provided by a single frequency stabilized oscillator. Sensor signals provided by the multiple sensor elements are controlled by multiple phase control units, which correspond to the multiple sensor elements, to adjust the sensor signals from the multiple sensor elements based on the frequency reference. The adjustment made to the sensor signals is indicated by output signals which indicate the proximity of the object. The output signals may also indicate the closing speed of the object based on the rate of change of the adjustment made, and the edges of the object based on a sudden decrease in the adjustment made.

Multi-Sensor Calibration of Low-Cost Magnetic, Angular Rate and Gravity Systems

PubMed Central

Lüken, Markus; Misgeld, Berno J.E.; Rüschen, Daniel; Leonhardt, Steffen

2015-01-01

We present a new calibration procedure for low-cost nine degrees-of-freedom (9DOF) magnetic, angular rate and gravity (MARG) sensor systems, which relies on a calibration cube, a reference table and a body sensor network (BSN). The 9DOF MARG sensor is part of our recently-developed “Integrated Posture and Activity Network by Medit Aachen” (IPANEMA) BSN. The advantage of this new approach is the use of the calibration cube, which allows for easy integration of two sensor nodes of the IPANEMA BSN. One 9DOF MARG sensor node is thereby used for calibration; the second 9DOF MARG sensor node is used for reference measurements. A novel algorithm uses these measurements to further improve the performance of the calibration procedure by processing arbitrarily-executed motions. In addition, the calibration routine can be used in an alignment procedure to minimize errors in the orientation between the 9DOF MARG sensor system and a motion capture inertial reference system. A two-stage experimental study is conducted to underline the performance of our calibration procedure. In both stages of the proposed calibration procedure, the BSN data, as well as reference tracking data are recorded. In the first stage, the mean values of all sensor outputs are determined as the absolute measurement offset to minimize integration errors in the derived movement model of the corresponding body segment. The second stage deals with the dynamic characteristics of the measurement system where the dynamic deviation of the sensor output compared to a reference system is corrected. In practical validation experiments, this procedure showed promising results with a maximum RMS error of 3.89°. PMID:26473873

Sensor Webs as Virtual Data Systems for Earth Science

NASA Astrophysics Data System (ADS)

Moe, K. L.; Sherwood, R.

2008-05-01

The NASA Earth Science Technology Office established a 3-year Advanced Information Systems Technology (AIST) development program in late 2006 to explore the technical challenges associated with integrating sensors, sensor networks, data assimilation and modeling components into virtual data systems called "sensor webs". The AIST sensor web program was initiated in response to a renewed emphasis on the sensor web concepts. In 2004, NASA proposed an Earth science vision for a more robust Earth observing system, coupled with remote sensing data analysis tools and advances in Earth system models. The AIST program is conducting the research and developing components to explore the technology infrastructure that will enable the visionary goals. A working statement for a NASA Earth science sensor web vision is the following: On-demand sensing of a broad array of environmental and ecological phenomena across a wide range of spatial and temporal scales, from a heterogeneous suite of sensors both in-situ and in orbit. Sensor webs will be dynamically organized to collect data, extract information from it, accept input from other sensor / forecast / tasking systems, interact with the environment based on what they detect or are tasked to perform, and communicate observations and results in real time. The focus on sensor webs is to develop the technology and prototypes to demonstrate the evolving sensor web capabilities. There are 35 AIST projects ranging from 1 to 3 years in duration addressing various aspects of sensor webs involving space sensors such as Earth Observing-1, in situ sensor networks such as the southern California earthquake network, and various modeling and forecasting systems. Some of these projects build on proof-of-concept demonstrations of sensor web capabilities like the EO-1 rapid fire response initially implemented in 2003. Other projects simulate future sensor web configurations to evaluate the effectiveness of sensor-model interactions for producing

Human Activity Recognition from Body Sensor Data using Deep Learning.

PubMed

Hassan, Mohammad Mehedi; Huda, Shamsul; Uddin, Md Zia; Almogren, Ahmad; Alrubaian, Majed

2018-04-16

In recent years, human activity recognition from body sensor data or wearable sensor data has become a considerable research attention from academia and health industry. This research can be useful for various e-health applications such as monitoring elderly and physical impaired people at Smart home to improve their rehabilitation processes. However, it is not easy to accurately and automatically recognize physical human activity through wearable sensors due to the complexity and variety of body activities. In this paper, we address the human activity recognition problem as a classification problem using wearable body sensor data. In particular, we propose to utilize a Deep Belief Network (DBN) model for successful human activity recognition. First, we extract the important initial features from the raw body sensor data. Then, a kernel principal component analysis (KPCA) and linear discriminant analysis (LDA) are performed to further process the features and make them more robust to be useful for fast activity recognition. Finally, the DBN is trained by these features. Various experiments were performed on a real-world wearable sensor dataset to verify the effectiveness of the deep learning algorithm. The results show that the proposed DBN outperformed other algorithms and achieves satisfactory activity recognition performance.

Adaptive sensor-fault tolerant control for a class of multivariable uncertain nonlinear systems.

PubMed

Khebbache, Hicham; Tadjine, Mohamed; Labiod, Salim; Boulkroune, Abdesselem

2015-03-01

This paper deals with the active fault tolerant control (AFTC) problem for a class of multiple-input multiple-output (MIMO) uncertain nonlinear systems subject to sensor faults and external disturbances. The proposed AFTC method can tolerate three additive (bias, drift and loss of accuracy) and one multiplicative (loss of effectiveness) sensor faults. By employing backstepping technique, a novel adaptive backstepping-based AFTC scheme is developed using the fact that sensor faults and system uncertainties (including external disturbances and unexpected nonlinear functions caused by sensor faults) can be on-line estimated and compensated via robust adaptive schemes. The stability analysis of the closed-loop system is rigorously proven using a Lyapunov approach. The effectiveness of the proposed controller is illustrated by two simulation examples. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Airport Remote Tower Sensor Systems

NASA Technical Reports Server (NTRS)

Papasin, Richard; Gawdiak, Yuri; Maluf, David A.; Leidich, Christopher; Tran, Peter B.

2001-01-01

Remote Tower Sensor Systems (RTSS) are proof-of-concept prototypes being developed by NASA/Ames Research Center (NASA/ARC) with collaboration with the FAA (Federal Aviation Administration) and NOAA (National Oceanic Atmospheric Administration). RTSS began with the deployment of an Airport Approach Zone Camera System that includes real-time weather observations at San Francisco International Airport. The goal of this research is to develop, deploy, and demonstrate remotely operated cameras and sensors at several major airport hubs and un-towered airports. RTSS can provide real-time weather observations of airport approach zone. RTSS will integrate and test airport sensor packages that will allow remote access to realtime airport conditions and aircraft status.

Image sensor system with bio-inspired efficient coding and adaptation.

PubMed

Okuno, Hirotsugu; Yagi, Tetsuya

2012-08-01

We designed and implemented an image sensor system equipped with three bio-inspired coding and adaptation strategies: logarithmic transform, local average subtraction, and feedback gain control. The system comprises a field-programmable gate array (FPGA), a resistive network, and active pixel sensors (APS), whose light intensity-voltage characteristics are controllable. The system employs multiple time-varying reset voltage signals for APS in order to realize multiple logarithmic intensity-voltage characteristics, which are controlled so that the entropy of the output image is maximized. The system also employs local average subtraction and gain control in order to obtain images with an appropriate contrast. The local average is calculated by the resistive network instantaneously. The designed system was successfully used to obtain appropriate images of objects that were subjected to large changes in illumination.

Solid-State Gas Sensors: Sensor System Challenges in the Civil Security Domain.

PubMed

Müller, Gerhard; Hackner, Angelika; Beer, Sebastian; Göbel, Johann

2016-01-20

The detection of military high explosives and illicit drugs presents problems of paramount importance in the fields of counter terrorism and criminal investigation. Effectively dealing with such threats requires hand-portable, mobile and affordable instruments. The paper shows that solid-state gas sensors can contribute to the development of such instruments provided the sensors are incorporated into integrated sensor systems, which acquire the target substances in the form of particle residue from suspect objects and which process the collected residue through a sequence of particle sampling, solid-vapor conversion, vapor detection and signal treatment steps. Considering sensor systems with metal oxide gas sensors at the backend, it is demonstrated that significant gains in sensitivity, selectivity and speed of response can be attained when the threat substances are sampled in particle as opposed to vapor form.

Active-Pixel Image Sensor With Analog-To-Digital Converters

NASA Technical Reports Server (NTRS)

Fossum, Eric R.; Mendis, Sunetra K.; Pain, Bedabrata; Nixon, Robert H.

1995-01-01

Proposed single-chip integrated-circuit image sensor contains 128 x 128 array of active pixel sensors at 50-micrometer pitch. Output terminals of all pixels in each given column connected to analog-to-digital (A/D) converter located at bottom of column. Pixels scanned in semiparallel fashion, one row at time; during time allocated to scanning row, outputs of all active pixel sensors in row fed to respective A/D converters. Design of chip based on complementary metal oxide semiconductor (CMOS) technology, and individual circuit elements fabricated according to 2-micrometer CMOS design rules. Active pixel sensors designed to operate at video rate of 30 frames/second, even at low light levels. A/D scheme based on first-order Sigma-Delta modulation.

Detection of Cardiopulmonary Activity and Related Abnormal Events Using Microsoft Kinect Sensor.

PubMed

Al-Naji, Ali; Chahl, Javaan

2018-03-20

Monitoring of cardiopulmonary activity is a challenge when attempted under adverse conditions, including different sleeping postures, environmental settings, and an unclear region of interest (ROI). This study proposes an efficient remote imaging system based on a Microsoft Kinect v2 sensor for the observation of cardiopulmonary-signal-and-detection-related abnormal cardiopulmonary events (e.g., tachycardia, bradycardia, tachypnea, bradypnea, and central apnoea) in many possible sleeping postures within varying environmental settings including in total darkness and whether the subject is covered by a blanket or not. The proposed system extracts the signal from the abdominal-thoracic region where cardiopulmonary activity is most pronounced, using a real-time image sequence captured by Kinect v2 sensor. The proposed system shows promising results in any sleep posture, regardless of illumination conditions and unclear ROI even in the presence of a blanket, whilst being reliable, safe, and cost-effective.

Detection of Cardiopulmonary Activity and Related Abnormal Events Using Microsoft Kinect Sensor

PubMed Central

Chahl, Javaan

2018-01-01

Monitoring of cardiopulmonary activity is a challenge when attempted under adverse conditions, including different sleeping postures, environmental settings, and an unclear region of interest (ROI). This study proposes an efficient remote imaging system based on a Microsoft Kinect v2 sensor for the observation of cardiopulmonary-signal-and-detection-related abnormal cardiopulmonary events (e.g., tachycardia, bradycardia, tachypnea, bradypnea, and central apnoea) in many possible sleeping postures within varying environmental settings including in total darkness and whether the subject is covered by a blanket or not. The proposed system extracts the signal from the abdominal-thoracic region where cardiopulmonary activity is most pronounced, using a real-time image sequence captured by Kinect v2 sensor. The proposed system shows promising results in any sleep posture, regardless of illumination conditions and unclear ROI even in the presence of a blanket, whilst being reliable, safe, and cost-effective. PMID:29558414

Recognition physical activities with optimal number of wearable sensors using data mining algorithms and deep belief network.

PubMed

Al-Fatlawi, Ali H; Fatlawi, Hayder K; Sai Ho Ling

2017-07-01

Daily physical activities monitoring is benefiting the health care field in several ways, in particular with the development of the wearable sensors. This paper adopts effective ways to calculate the optimal number of the necessary sensors and to build a reliable and a high accuracy monitoring system. Three data mining algorithms, namely Decision Tree, Random Forest and PART Algorithm, have been applied for the sensors selection process. Furthermore, the deep belief network (DBN) has been investigated to recognise 33 physical activities effectively. The results indicated that the proposed method is reliable with an overall accuracy of 96.52% and the number of sensors is minimised from nine to six sensors.

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.

A simulation environment for assisting system design of coherent laser doppler wind sensor for active wind turbine pitch control

NASA Astrophysics Data System (ADS)

Shinohara, Leilei; Pham Tran, Tuan Anh; Beuth, Thorsten; Umesh Babu, Harsha; Heussner, Nico; Bogatscher, Siegwart; Danilova, Svetlana; Stork, Wilhelm

2013-05-01

In order to assist a system design of laser coherent Doppler wind sensor for active pitch control of wind turbine systems (WTS), we developed a numerical simulation environment for modeling and simulation of the sensor system. In this paper we present this simulation concept. In previous works, we have shown the general idea and the possibility of using a low cost coherent laser Doppler wind sensing system for an active pitch control of WTS in order to achieve a reduced mechanical stress, increase the WTS lifetime and therefore reduce the electricity price from wind energy. Such a system is based on a 1.55μm Continuous-Wave (CW) laser plus an erbium-doped fiber amplifier (EDFA) with an output power of 1W. Within this system, an optical coherent detection method is chosen for the Doppler frequency measurement in megahertz range. A comparatively low cost short coherent length laser with a fiber delay line is used for achieving a multiple range measurement. In this paper, we show the current results on the improvement of our simulation by applying a Monte Carlo random generation method for positioning the random particles in atmosphere and extend the simulation to the entire beam penetrated space by introducing a cylindrical co-ordinate concept and meshing the entire volume into small elements in order to achieve a faster calculation and gain more realistic simulation result. In addition, by applying different atmospheric parameters, such as particle sizes and distributions, we can simulate different weather and wind situations.

Battery management system with distributed wireless sensors

DOEpatents

Farmer, Joseph C.; Bandhauer, Todd M.

2016-02-23

A system for monitoring parameters of an energy storage system having a multiplicity of individual energy storage cells. A radio frequency identification and sensor unit is connected to each of the individual energy storage cells. The radio frequency identification and sensor unit operates to sense the parameter of each individual energy storage cell and provides radio frequency transmission of the parameters of each individual energy storage cell. A management system monitors the radio frequency transmissions from the radio frequency identification and sensor units for monitoring the parameters of the energy storage system.

Modular Bayesian Networks with Low-Power Wearable Sensors for Recognizing Eating Activities

PubMed Central

Kim, Kee-Hoon

2017-01-01

Recently, recognizing a user’s daily activity using a smartphone and wearable sensors has become a popular issue. However, in contrast with the ideal definition of an experiment, there could be numerous complex activities in real life with respect to its various background and contexts: time, space, age, culture, and so on. Recognizing these complex activities with limited low-power sensors, considering the power and memory constraints of the wearable environment and the user’s obtrusiveness at once is not an easy problem, although it is very crucial for the activity recognizer to be practically useful. In this paper, we recognize activity of eating, which is one of the most typical examples of a complex activity, using only daily low-power mobile and wearable sensors. To organize the related contexts systemically, we have constructed the context model based on activity theory and the “Five W’s”, and propose a Bayesian network with 88 nodes to predict uncertain contexts probabilistically. The structure of the proposed Bayesian network is designed by a modular and tree-structured approach to reduce the time complexity and increase the scalability. To evaluate the proposed method, we collected the data with 10 different activities from 25 volunteers of various ages, occupations, and jobs, and have obtained 79.71% accuracy, which outperforms other conventional classifiers by 7.54–14.4%. Analyses of the results showed that our probabilistic approach could also give approximate results even when one of contexts or sensor values has a very heterogeneous pattern or is missing. PMID:29232937

Modular Bayesian Networks with Low-Power Wearable Sensors for Recognizing Eating Activities.

PubMed

Kim, Kee-Hoon; Cho, Sung-Bae

2017-12-11

Recently, recognizing a user's daily activity using a smartphone and wearable sensors has become a popular issue. However, in contrast with the ideal definition of an experiment, there could be numerous complex activities in real life with respect to its various background and contexts: time, space, age, culture, and so on. Recognizing these complex activities with limited low-power sensors, considering the power and memory constraints of the wearable environment and the user's obtrusiveness at once is not an easy problem, although it is very crucial for the activity recognizer to be practically useful. In this paper, we recognize activity of eating, which is one of the most typical examples of a complex activity, using only daily low-power mobile and wearable sensors. To organize the related contexts systemically, we have constructed the context model based on activity theory and the "Five W's", and propose a Bayesian network with 88 nodes to predict uncertain contexts probabilistically. The structure of the proposed Bayesian network is designed by a modular and tree-structured approach to reduce the time complexity and increase the scalability. To evaluate the proposed method, we collected the data with 10 different activities from 25 volunteers of various ages, occupations, and jobs, and have obtained 79.71% accuracy, which outperforms other conventional classifiers by 7.54-14.4%. Analyses of the results showed that our probabilistic approach could also give approximate results even when one of contexts or sensor values has a very heterogeneous pattern or is missing.

Multiagent robotic systems' ambient light sensor

NASA Astrophysics Data System (ADS)

Iureva, Radda A.; Maslennikov, Oleg S.; Komarov, Igor I.

2017-05-01

Swarm robotics is one of the fastest growing areas of modern technology. Being subclass of multi-agent systems it inherits the main part of scientific-methodological apparatus of construction and functioning of practically useful complexes, which consist of rather autonomous independent agents. Ambient light sensors (ALS) are widely used in robotics. But speaking about swarm robotics, the technology which has great number of specific features and is developing, we can't help mentioning that its important to use sensors on each robot not only in order to help it to get directionally oriented, but also to follow light emitted by robot-chief or to help to find the goal easier. Key words: ambient light sensor, swarm system, multiagent system, robotic system, robotic complexes, simulation modelling

The application of micromachined sensors to manned space systems

NASA Technical Reports Server (NTRS)

Bordano, Aldo; Havey, Gary; Wald, Jerry; Nasr, Hatem

1993-01-01

Micromachined sensors promise significant system advantages to manned space vehicles. Vehicle Health Monitoring (VHM) is a critical need for most future space systems. Micromachined sensors play a significant role in advancing the application of VHM in future space vehicles. This paper addresses the requirements that future VHM systems place on micromachined sensors such as: system integration, performance, size, weight, power, redundancy, reliability and fault tolerance. Current uses of micromachined sensors in commercial, military and space systems are used to document advantages that are gained and lessons learned. Based on these successes, the future use of micromachined sensors in space programs is discussed in terms of future directions and issues that need to be addressed such as how commercial and military sensors can meet future space system requirements.

Simulating optoelectronic systems for remote sensing with SENSOR

NASA Astrophysics Data System (ADS)

Boerner, Anko

2003-04-01

The consistent end-to-end simulation of airborne and spaceborne remote sensing systems is an important task and sometimes the only way for the adaptation and optimization of a sensor and its observation conditions, the choice and test of algorithms for data processing, error estimation and the evaluation of the capabilities of the whole sensor system. The presented software simulator SENSOR (Software ENvironment for the Simulation of Optical Remote sensing systems) includes a full model of the sensor hardware, the observed scene, and the atmosphere in between. It allows the simulation of a wide range of optoelectronic systems for remote sensing. The simulator consists of three parts. The first part describes the geometrical relations between scene, sun, and the remote sensing system using a ray tracing algorithm. The second part of the simulation environment considers the radiometry. It calculates the at-sensor radiance using a pre-calculated multidimensional lookup-table taking the atmospheric influence on the radiation into account. Part three consists of an optical and an electronic sensor model for the generation of digital images. Using SENSOR for an optimization requires the additional application of task-specific data processing algorithms. The principle of the end-to-end-simulation approach is explained, all relevant concepts of SENSOR are discussed, and examples of its use are given. The verification of SENSOR is demonstrated.

Piezoelectric Active Humidity Sensors Based on Lead-Free NaNbO₃ Piezoelectric Nanofibers.

PubMed

Gu, Li; Zhou, Di; Cao, Jun Cheng

2016-06-07

The development of micro-/nano-scaled energy harvesters and the self-powered sensor system has attracted great attention due to the miniaturization and integration of the micro-device. In this work, lead-free NaNbO₃ piezoelectric nanofibers with a monoclinic perovskite structure were synthesized by the far-field electrospinning method. The flexible active humidity sensors were fabricated by transferring the nanofibers from silicon to a soft polymer substrate. The sensors exhibited outstanding piezoelectric energy-harvesting performance with output voltage up to 2 V during the vibration process. The output voltage generated by the NaNbO₃ sensors exhibited a negative correlation with the environmental humidity varying from 5% to 80%, where the peak-to-peak value of the output voltage generated by the sensors decreased from 0.40 to 0.07 V. The sensor also exhibited a short response time, good selectively against ethanol steam, and great temperature stability. The piezoelectric active humidity sensing property could be attributed to the increased leakage current in the NaNbO₃ nanofibers, which was generated due to proton hopping among the H₃O⁺ groups in the absorbed H₂O layers under the driving force of the piezoelectric potential.

A Brief Overview of NASA Glenn Research Center Sensor and Electronics Activities

NASA Technical Reports Server (NTRS)

Hunter, Gary W.

2012-01-01

Aerospace applications require a range of sensing technologies. There is a range of sensor and sensor system technologies being developed using microfabrication and micromachining technology to form smart sensor systems and intelligent microsystems. Drive system intelligence to the local (sensor) level -- distributed smart sensor systems. Sensor and sensor system development examples: (1) Thin-film physical sensors (2) High temperature electronics and wireless (3) "lick and stick" technology. NASA GRC is a world leader in aerospace sensor technology with a broad range of development and application experience. Core microsystems technology applicable to a range of application environmentS.

Intelligent Sensors: Strategies for an Integrated Systems Approach

NASA Technical Reports Server (NTRS)

Chitikeshi, Sanjeevi; Mahajan, Ajay; Bandhil, Pavan; Utterbach, Lucas; Figueroa, Fernando

2005-01-01

This paper proposes the development of intelligent sensors as an integrated systems approach, i.e. one treats the sensors as a complete system with its own sensing hardware (the traditional sensor), A/D converters, processing and storage capabilities, software drivers, self-assessment algorithms, communication protocols and evolutionary methodologies that allow them to get better with time. Under a project being undertaken at the Stennis Space Center, an integrated framework is being developed for the intelligent monitoring of smart elements. These smart elements can be sensors, actuators or other devices. The immediate application is the monitoring of the rocket test stands, but the technology should be generally applicable to the Intelligent Systems Health Monitoring (ISHM) vision. This paper outlines progress made in the development of intelligent sensors by describing the work done till date on Physical Intelligent Sensors (PIS) and Virtual Intelligent Sensors (VIS).

Sensor system for fuel transport vehicle

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

Earl, Dennis Duncan; McIntyre, Timothy J.; West, David L.

An exemplary sensor system for a fuel transport vehicle can comprise a fuel marker sensor positioned between a fuel storage chamber of the vehicle and an access valve for the fuel storage chamber of the vehicle. The fuel marker sensor can be configured to measure one or more characteristics of one or more fuel markers present in the fuel adjacent the sensor, such as when the marked fuel is unloaded at a retail station. The one or more characteristics can comprise concentration and/or identity of the one or more fuel markers in the fuel. Based on the measured characteristics ofmore » the one or more fuel markers, the sensor system can identify the fuel and/or can determine whether the fuel has been adulterated after the marked fuel was last measured, such as when the marked fuel was loaded into the vehicle.« less

Fluorescent sensors reporting the activity of ammonium transceptors in live cells

DOE PAGES

De Michele, Roberto; Ast, Cindy; Loqué, Dominique; ...

2013-07-02

Ammonium serves as key nitrogen source and metabolic intermediate, yet excess causes toxicity. Ammonium uptake is mediated by ammonium transporters, whose regulation is poorly understood. While transport can easily be characterized in heterologous systems, measuring transporter activity in vivo remains challenging. Here we developed a simple assay for monitoring activity in vivo by inserting circularly-permutated GFP into conformation-sensitive positions of two plant and one yeast ammonium transceptors (‘AmTrac’ and ‘MepTrac’). Addition of ammonium to yeast cells expressing the sensors triggered concentration-dependent fluorescence intensity (FI) changes that strictly correlated with the activity of the transporter. Fluorescence-based activity sensors present a novelmore » technology for monitoring the interaction of the transporters with their substrates, the activity of transporters and their regulation in vivo, which is particularly valuable in the context of analytes for which no radiotracers exist, as well as for cell-specific and subcellular transport processes that are otherwise difficult to track.« less

Vibration welding system with thin film sensor

DOEpatents

Cai, Wayne W; Abell, Jeffrey A; Li, Xiaochun; Choi, Hongseok; Zhao, Jingzhou

2014-03-18

A vibration welding system includes an anvil, a welding horn, a thin film sensor, and a process controller. The anvil and horn include working surfaces that contact a work piece during the welding process. The sensor measures a control value at the working surface. The measured control value is transmitted to the controller, which controls the system in part using the measured control value. The thin film sensor may include a plurality of thermopiles and thermocouples which collectively measure temperature and heat flux at the working surface. A method includes providing a welder device with a slot adjacent to a working surface of the welder device, inserting the thin film sensor into the slot, and using the sensor to measure a control value at the working surface. A process controller then controls the vibration welding system in part using the measured control value.

Solid-State Gas Sensors: Sensor System Challenges in the Civil Security Domain

PubMed Central

Müller, Gerhard; Hackner, Angelika; Beer, Sebastian; Göbel, Johann

2016-01-01

The detection of military high explosives and illicit drugs presents problems of paramount importance in the fields of counter terrorism and criminal investigation. Effectively dealing with such threats requires hand-portable, mobile and affordable instruments. The paper shows that solid-state gas sensors can contribute to the development of such instruments provided the sensors are incorporated into integrated sensor systems, which acquire the target substances in the form of particle residue from suspect objects and which process the collected residue through a sequence of particle sampling, solid-vapor conversion, vapor detection and signal treatment steps. Considering sensor systems with metal oxide gas sensors at the backend, it is demonstrated that significant gains in sensitivity, selectivity and speed of response can be attained when the threat substances are sampled in particle as opposed to vapor form. PMID:28787865

Novel Corrosion Sensor for Vision 21 Systems

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

Heng Ban; Bharat Soni

2007-03-31

Advanced sensor technology is identified as a key component for advanced power systems for future energy plants that would have virtually no environmental impact. This project intends to develop a novel high temperature corrosion sensor and subsequent measurement system for advanced power systems. Fireside corrosion is the leading mechanism for boiler tube failures and has emerged to be a significant concern for current and future energy plants due to the introduction of technologies targeting emissions reduction, efficiency improvement, or fuel/oxidant flexibility. Corrosion damage can lead to catastrophic equipment failure, explosions, and forced outages. Proper management of corrosion requires real-time indicationmore » of corrosion rate. However, short-term, on-line corrosion monitoring systems for fireside corrosion remain a technical challenge to date due to the extremely harsh combustion environment. The overall goal of this project is to develop a technology for on-line fireside corrosion monitoring. This objective is achieved by the laboratory development of sensors and instrumentation, testing them in a laboratory muffle furnace, and eventually testing the system in a coal-fired furnace. This project successfully developed two types of sensors and measurement systems, and successful tested them in a muffle furnace in the laboratory. The capacitance sensor had a high fabrication cost and might be more appropriate in other applications. The low-cost resistance sensor was tested in a power plant burning eastern bituminous coals. The results show that the fireside corrosion measurement system can be used to determine the corrosion rate at waterwall and superheater locations. Electron microscope analysis of the corroded sensor surface provided detailed picture of the corrosion process.« less

Genetically encoded proton sensors reveal activity-dependent pH changes in neurons.

PubMed

Raimondo, Joseph V; Irkle, Agnese; Wefelmeyer, Winnie; Newey, Sarah E; Akerman, Colin J

2012-01-01

The regulation of hydrogen ion concentration (pH) is fundamental to cell viability, metabolism, and enzymatic function. Within the nervous system, the control of pH is also involved in diverse and dynamic processes including development, synaptic transmission, and the control of network excitability. As pH affects neuronal activity, and can also itself be altered by neuronal activity, the existence of tools to accurately measure hydrogen ion fluctuations is important for understanding the role pH plays under physiological and pathological conditions. Outside of their use as a marker of synaptic release, genetically encoded pH sensors have not been utilized to study hydrogen ion fluxes associated with network activity. By combining whole-cell patch clamp with simultaneous two-photon or confocal imaging, we quantified the amplitude and time course of neuronal, intracellular, acidic transients evoked by epileptiform activity in two separate in vitro models of temporal lobe epilepsy. In doing so, we demonstrate the suitability of three genetically encoded pH sensors: deGFP4, E(2)GFP, and Cl-sensor for investigating activity-dependent pH changes at the level of single neurons.

ALPIDE, the Monolithic Active Pixel Sensor for the ALICE ITS upgrade

NASA Astrophysics Data System (ADS)

Mager, M.; ALICE Collaboration

2016-07-01

A new 10 m2 inner tracking system based on seven concentric layers of Monolithic Active Pixel Sensors will be installed in the ALICE experiment during the second long shutdown of LHC in 2019-2020. The monolithic pixel sensors will be fabricated in the 180 nm CMOS Imaging Sensor process of TowerJazz. The ALPIDE design takes full advantage of a particular process feature, the deep p-well, which allows for full CMOS circuitry within the pixel matrix, while at the same time retaining the full charge collection efficiency. Together with the small feature size and the availability of six metal layers, this allowed a continuously active low-power front-end to be placed into each pixel and an in-matrix sparsification circuit to be used that sends only the addresses of hit pixels to the periphery. This approach led to a power consumption of less than 40 mWcm-2, a spatial resolution of around 5 μm, a peaking time of around 2 μs, while being radiation hard to some 1013 1 MeVneq /cm2, fulfilling or exceeding the ALICE requirements. Over the last years of R & D, several prototype circuits have been used to verify radiation hardness, and to optimize pixel geometry and in-pixel front-end circuitry. The positive results led to a submission of full-scale (3 cm×1.5 cm) sensor prototypes in 2014. They are being characterized in a comprehensive campaign that also involves several irradiation and beam tests. A summary of the results obtained and prospects towards the final sensor to instrument the ALICE Inner Tracking System are given.

Active Sensor for Microwave Tissue Imaging with Bias-Switched Arrays.

PubMed

Foroutan, Farzad; Nikolova, Natalia K

2018-05-06

A prototype of a bias-switched active sensor was developed and measured to establish the achievable dynamic range in a new generation of active arrays for microwave tissue imaging. The sensor integrates a printed slot antenna, a low-noise amplifier (LNA) and an active mixer in a single unit, which is sufficiently small to enable inter-sensor separation distance as small as 12 mm. The sensor’s input covers the bandwidth from 3 GHz to 7.5 GHz. Its output intermediate frequency (IF) is 30 MHz. The sensor is controlled by a simple bias-switching circuit, which switches ON and OFF the bias of the LNA and the mixer simultaneously. It was demonstrated experimentally that the dynamic range of the sensor, as determined by its ON and OFF states, is 109 dB and 118 dB at resolution bandwidths of 1 kHz and 100 Hz, respectively.

Noise activated bistable sensor based on chaotic system with output defined by temporal coding and firing rate

NASA Astrophysics Data System (ADS)

Korneta, Wojciech; Gomes, Iacyel

2017-11-01

Traditional bistable sensors use external bias signal to drive its response between states and their detection strategy is based on the output power spectral density or the residence time difference (RTD) in two sensor states. Recently, the noise activated nonlinear dynamic sensors driven only by noise based on RTD technique have been proposed. Here, we present experimental results of dc voltage measurements by noise-driven bistable sensor based on electronic Chua's circuit operating in a chaotic regime where two single scroll attractors coexist. The output of the sensor is quantified by the proportion of the time the sensor stays in one state to the total observation time and by the spike-count rate with spikes defined by crossings between attractors. The relationship between the stimuli and particular observable for different noise intensities is obtained, the usefulness of each coding scheme is discussed, and the optimal noise intensity for detection is indicated. It is shown that the obtained relationship is the same for any observation time when population coding is used. The optimal time window for both detection and the number of units in population coding is found. Our results may be useful for analyses and understanding of the neural activity and in designing bistable storage elements at length scales where thermal fluctuations drastically increase and the effect of noise must be taken into consideration.

Wearable Networked Sensing for Human Mobility and Activity Analytics: A Systems Study.

PubMed

Dong, Bo; Biswas, Subir

2012-01-01

This paper presents implementation details, system characterization, and the performance of a wearable sensor network that was designed for human activity analysis. Specific machine learning mechanisms are implemented for recognizing a target set of activities with both out-of-body and on-body processing arrangements. Impacts of energy consumption by the on-body sensors are analyzed in terms of activity detection accuracy for out-of-body processing. Impacts of limited processing abilities in the on-body scenario are also characterized in terms of detection accuracy, by varying the background processing load in the sensor units. Through a rigorous systems study, it is shown that an efficient human activity analytics system can be designed and operated even under energy and processing constraints of tiny on-body wearable sensors.

Characterization of Dutch dairy farms using sensor systems for cow management.

PubMed

Steeneveld, W; Hogeveen, H

2015-01-01

To improve cow management in large dairy herds, sensors have been developed that can measure physiological, behavioral, and production indicators on individual cows. Recently, the number of dairy farms using sensor systems has increased. It is not known, however, to what extent sensor systems are used on dairy farms, and the reasons why farmers invest or not in sensor systems are unclear. The first objective of this study was to give an overview of the sensor systems currently used in the Netherlands. The second objective was to investigate the reasons for investing or not investing in sensor systems. The third objective was to characterize farms with and without sensor systems. A survey was developed to investigate first, the reasons for investing or not in sensor systems and, then, how the sensor systems are used in daily cow management. The survey was sent to 1,672 Dutch dairy farmers. The final data set consisted of 512 dairy farms (response rate of 30.6%); 202 farms indicated that they had sensor systems and 310 farms indicated that they did not have sensor systems. A wide variety of sensor systems was used on Dutch dairy farms; those for mastitis detection and estrus detection were the most-used sensor systems. The use of sensor systems was different for farms using an automatic milking system (AMS) and a conventional milking system (CMS). Reasons for investing were different for different sensor systems. For sensor systems attached to the AMS, the farmers made no conscious decision to invest: they answered that the sensors were standard in the AMS or were bought for reduced cost with the AMS. The main reasons for investing in estrus detection sensor systems were improving detection rates, gaining insights into the fertility level of the herd, improving profitability of the farm, and reducing labor. Main reasons for not investing in sensor systems were economically related. It was very difficult to characterize farms with and without sensor systems. Farms

Wearable motion sensors to continuously measure real-world physical activities.

PubMed

Dobkin, Bruce H

2013-12-01

Rehabilitation for sensorimotor impairments aims to improve daily activities, walking, exercise, and motor skills. Monitoring of practice and measuring outcomes, however, is usually restricted to laboratory-based procedures and self-reports. Mobile health devices may reverse these confounders of daily care and research trials. Wearable, wireless motion sensor data, analyzed by activity pattern-recognition algorithms, can describe the type, quantity, and quality of mobility-related activities in the community. Data transmission from the sensors to a cell phone and the Internet enable continuous monitoring. Remote access to laboratory quality data about walking speed, duration and distance, gait asymmetry and smoothness of movements, as well as cycling, exercise, and skills practice, opens new opportunities to engage patients in progressive, personalized therapies with feedback about the performance. Clinical trial designs will be able to include remote verification of the integrity of complex physical interventions and compliance with practice, as well as capture repeated, ecologically sound, ratio scale outcome measures. Given the progressively falling cost of miniaturized wearable gyroscopes, accelerometers, and other physiologic sensors, as well as inexpensive data transmission, sensing systems may become as ubiquitous as cell phones for healthcare. Neurorehabilitation can develop these mobile health platforms for daily care and clinical trials to improve exercise and fitness, skills learning, and physical functioning.

Individually Identifiable Surface Acoustic Wave Sensors, Tags and Systems

NASA Technical Reports Server (NTRS)

Hines, Jacqueline H. (Inventor); Solie, Leland P. (Inventor); Tucker, Dana Y. G. (Inventor); Hines, Andrew T. (Inventor)

2017-01-01

A surface-launched acoustic wave sensor tag system for remotely sensing and/or providing identification information using sets of surface acoustic wave (SAW) sensor tag devices is characterized by acoustic wave device embodiments that include coding and other diversity techniques to produce groups of sensors that interact minimally, reducing or alleviating code collision problems typical of prior art coded SAW sensors and tags, and specific device embodiments of said coded SAW sensor tags and systems. These sensor/tag devices operate in a system which consists of one or more uniquely identifiable sensor/tag devices and a wireless interrogator. The sensor device incorporates an antenna for receiving incident RF energy and re-radiating the tag identification information and the sensor measured parameter(s). Since there is no power source in or connected to the sensor, it is a passive sensor. The device is wirelessly interrogated by the interrogator.

Steel bridge fatigue crack detection with piezoelectric wafer active sensors

NASA Astrophysics Data System (ADS)

Yu, Lingyu; Giurgiutiu, Victor; Ziehl, Paul; Ozevin, Didem; Pollock, Patrick

2010-04-01

Piezoelectric wafer active sensors (PWAS) are well known for its dual capabilities in structural health monitoring, acting as either actuators or sensors. Due to the variety of deterioration sources and locations of bridge defects, there is currently no single method that can detect and address the potential sources globally. In our research, our use of the PWAS based sensing has the novelty of implementing both passive (as acoustic emission) and active (as ultrasonic transducers) sensing with a single PWAS network. The combined schematic is using acoustic emission to detect the presence of fatigue cracks in steel bridges in their early stage since methods such as ultrasonics are unable to quantify the initial condition of crack growth since most of the fatigue life for these details is consumed while the fatigue crack is too small to be detected. Hence, combing acoustic emission with ultrasonic active sensing will strengthen the damage detection process. The integration of passive acoustic emission detection with active sensing will be a technological leap forward from the current practice of periodic and subjective visual inspection, and bridge management based primarily on history of past performance. In this study, extensive laboratory investigation is performed supported by theoretical modeling analysis. A demonstration system will be presented to show how piezoelectric wafer active sensor is used for acoustic emission. Specimens representing complex structures are tested. The results will also be compared with traditional acoustic emission transducers to identify the application barriers.

Sensor-integrated polymer actuators for closed-loop drug delivery system

NASA Astrophysics Data System (ADS)

Xu, Han; Wang, Chunlei; Kulinsky, Lawrence; Zoval, Jim; Madou, Marc

2006-03-01

This work presents manufacturing and testing of a closed-loop drug delivery system where drug release is achieved by an electrochemical actuation of an array of polymeric valves on a set of drug reservoirs. The valves are based on bi-layer structures made of polypyrrole/gold in the shape of a flap that is hinged on one side of a valve seat. Drugs stored in the underlying chambers are released by bending the bi-layer flaps back with a small applied bias. These polymeric valves simultaneously function as both drug release components and biological/chemical sensors responding to a specific biological or environmental stimulus. The sensors may send signals to the control module to realize closed-loop control of the drug release. In this study a glucose sensor has been integrated with the polymeric actuators through immobilization of glucose oxidase(GOx) within polypyrrole(PPy) valves. Sensitivities per unit area of the integrated glucose sensor have been measured and compared before and after the actuation of the sensor/actuator PPy/DBS/GOx film. Other sensing parameters such as linear range and response time were discussed as well. Using an array of these sensor/actuator cells, the amount of released drug, e.g. insulin, can be precisely controlled according to the surrounding glucose concentration detected by the glucose sensor. Activation of these reservoirs can be triggered either by the signal from the sensor, or by the signal from the operator. This approach also serves as the initial step to use the proposed system as an implantable drug delivery platform in the future.

Phosphatase activity of the voltage-sensing phosphatase, VSP, shows graded dependence on the extent of activation of the voltage sensor

PubMed Central

Sakata, Souhei; Okamura, Yasushi

2014-01-01

The voltage-sensing phosphatase (VSP) consists of a voltage sensor and a cytoplasmic phosphatase region, and the movement of the voltage sensor is coupled to the phosphatase activity. However, its coupling mechanisms still remain unclear. One possible scenario is that the phosphatase is activated only when the voltage sensor is in a fully activated state. Alternatively, the enzymatic activity of single VSP proteins could be graded in distinct activated states of the voltage sensor, and partial activation of the voltage sensor could lead to partial activation of the phosphatase. To distinguish between these two possibilities, we studied a voltage sensor mutant of zebrafish VSP, where the voltage sensor moves in two steps as evidenced by analyses of charge movements of the voltage sensor and voltage clamp fluorometry. Measurements of the phosphatase activity toward phosphatidylinositol 4,5-bisphosphate revealed that both steps of voltage sensor activation are coupled to the tuning of phosphatase activities, consistent with the idea that the phosphatase activity is graded by the magnitude of the movement of the voltage sensor. PMID:24277865

Phosphatase activity of the voltage-sensing phosphatase, VSP, shows graded dependence on the extent of activation of the voltage sensor.

PubMed

Sakata, Souhei; Okamura, Yasushi

2014-03-01

The voltage-sensing phosphatase (VSP) consists of a voltage sensor and a cytoplasmic phosphatase region, and the movement of the voltage sensor is coupled to the phosphatase activity. However, its coupling mechanisms still remain unclear. One possible scenario is that the phosphatase is activated only when the voltage sensor is in a fully activated state. Alternatively, the enzymatic activity of single VSP proteins could be graded in distinct activated states of the voltage sensor, and partial activation of the voltage sensor could lead to partial activation of the phosphatase. To distinguish between these two possibilities, we studied a voltage sensor mutant of zebrafish VSP, where the voltage sensor moves in two steps as evidenced by analyses of charge movements of the voltage sensor and voltage clamp fluorometry. Measurements of the phosphatase activity toward phosphatidylinositol 4,5-bisphosphate revealed that both steps of voltage sensor activation are coupled to the tuning of phosphatase activities, consistent with the idea that the phosphatase activity is graded by the magnitude of the movement of the voltage sensor.

Optimal Sensor Placement for Measuring Physical Activity with a 3D Accelerometer

PubMed Central

Boerema, Simone T.; van Velsen, Lex; Schaake, Leendert; Tönis, Thijs M.; Hermens, Hermie J.

2014-01-01

Accelerometer-based activity monitors are popular for monitoring physical activity. In this study, we investigated optimal sensor placement for increasing the quality of studies that utilize accelerometer data to assess physical activity. We performed a two-staged study, focused on sensor location and type of mounting. Ten subjects walked at various walking speeds on a treadmill, performed a deskwork protocol, and walked on level ground, while simultaneously wearing five ProMove2 sensors with a snug fit on an elastic waist belt. We found that sensor location, type of activity, and their interaction-effect affected sensor output. The most lateral positions on the waist belt were the least sensitive for interference. The effect of mounting was explored, by making two subjects repeat the experimental protocol with sensors more loosely fitted to the elastic belt. The loose fit resulted in lower sensor output, except for the deskwork protocol, where output was higher. In order to increase the reliability and to reduce the variability of sensor output, researchers should place activity sensors on the most lateral position of a participant's waist belt. If the sensor hampers free movement, it may be positioned slightly more forward on the belt. Finally, sensors should be fitted tightly to the body. PMID:24553085

Optical seismic sensor systems and methods

DOEpatents

Beal, A. Craig; Cummings, Malcolm E.; Zavriyev, Anton; Christensen, Caleb A.; Lee, Keun

2015-12-08

Disclosed is an optical seismic sensor system for measuring seismic events in a geological formation, including a surface unit for generating and processing an optical signal, and a sensor device optically connected to the surface unit for receiving the optical signal over an optical conduit. The sensor device includes at least one sensor head for sensing a seismic disturbance from at least one direction during a deployment of the sensor device within a borehole of the geological formation. The sensor head includes a frame and a reference mass attached to the frame via at least one flexure, such that movement of the reference mass relative to the frame is constrained to a single predetermined path.

Annotating smart environment sensor data for activity learning.

PubMed

Szewcyzk, S; Dwan, K; Minor, B; Swedlove, B; Cook, D

2009-01-01

The pervasive sensing technologies found in smart homes offer unprecedented opportunities for providing health monitoring and assistance to individuals experiencing difficulties living independently at home. In order to monitor the functional health of smart home residents, we need to design technologies that recognize and track the activities that people perform at home. Machine learning techniques can perform this task, but the software algorithms rely upon large amounts of sample data that is correctly labeled with the corresponding activity. Labeling, or annotating, sensor data with the corresponding activity can be time consuming, may require input from the smart home resident, and is often inaccurate. Therefore, in this paper we investigate four alternative mechanisms for annotating sensor data with a corresponding activity label. We evaluate the alternative methods along the dimensions of annotation time, resident burden, and accuracy using sensor data collected in a real smart apartment.

Precise nanoliter fluid handling system with integrated high-speed flow sensor.

PubMed

Haber, Carsten; Boillat, Marc; van der Schoot, Bart

2005-04-01

A system for accurate low-volume delivery of liquids in the micro- to nanoliter range makes use of an integrated miniature flow sensor as part of an intelligent feedback control loop driving a micro-solenoid valve. The flow sensor is hydraulically connected with the pressurized system liquid in the dispensing channel and located downstream from the pressure source, above the solenoid valve. The sensor operates in a differential mode and responds in real-time to the internal flow-pulse resulting from the brief opening interval of the solenoid valve leading to a rapid ejection of a fluid droplet. The integral of the flow-pulse delivered by the sensor is directly proportional to the volume of the ejected droplet from the nozzle. The quantitative information is utilized to provide active control of the effectively dispensed or aspirated volume by adjusting the solenoid valve accordingly. This process significantly enhances the precision of the fluid delivery. The system furthermore compensates automatically for any changes in the viscosity of the dispensed liquid. The data delivered by the flow sensor can be saved and backtracked in order to confirm and validate the aspiration and dispensing process in its entirety. The collected dispense information can be used for quality control assessments and automatically be made part of an electronic record.

Active State Model for Autonomous Systems

NASA Technical Reports Server (NTRS)

Park, Han; Chien, Steve; Zak, Michail; James, Mark; Mackey, Ryan; Fisher, Forest

2003-01-01

The concept of the active state model (ASM) is an architecture for the development of advanced integrated fault-detection-and-isolation (FDI) systems for robotic land vehicles, pilotless aircraft, exploratory spacecraft, or other complex engineering systems that will be capable of autonomous operation. An FDI system based on the ASM concept would not only provide traditional diagnostic capabilities, but also integrate the FDI system under a unified framework and provide mechanism for sharing of information between FDI subsystems to fully assess the overall health of the system. The ASM concept begins with definitions borrowed from psychology, wherein a system is regarded as active when it possesses self-image, self-awareness, and an ability to make decisions itself, such that it is able to perform purposeful motions and other transitions with some degree of autonomy from the environment. For an engineering system, self-image would manifest itself as the ability to determine nominal values of sensor data by use of a mathematical model of itself, and selfawareness would manifest itself as the ability to relate sensor data to their nominal values. The ASM for such a system may start with the closed-loop control dynamics that describe the evolution of state variables. As soon as this model was supplemented with nominal values of sensor data, it would possess self-image. The ability to process the current sensor data and compare them with the nominal values would represent self-awareness. On the basis of self-image and self-awareness, the ASM provides the capability for self-identification, detection of abnormalities, and self-diagnosis.

Identifying compensatory movement patterns in the upper extremity using a wearable sensor system.

PubMed

Ranganathan, Rajiv; Wang, Rui; Dong, Bo; Biswas, Subir

2017-11-30

Movement impairments such as those due to stroke often result in the nervous system adopting atypical movements to compensate for movement deficits. Monitoring these compensatory patterns is critical for improving functional outcomes during rehabilitation. The purpose of this study was to test the feasibility and validity of a wearable sensor system for detecting compensatory trunk kinematics during activities of daily living. Participants with no history of neurological impairments performed reaching and manipulation tasks with their upper extremity, and their movements were recorded by a wearable sensor system and validated using a motion capture system. Compensatory movements of the trunk were induced using a brace that limited range of motion at the elbow. Our results showed that the elbow brace elicited compensatory movements of the trunk during reaching tasks but not manipulation tasks, and that a wearable sensor system with two sensors could reliably classify compensatory movements (~90% accuracy). These results show the potential of the wearable system to assess and monitor compensatory movements outside of a lab setting.

A Wearable Context-Aware ECG Monitoring System Integrated with Built-in Kinematic Sensors of the Smartphone.

PubMed

Miao, Fen; Cheng, Yayu; He, Yi; He, Qingyun; Li, Ye

2015-05-19

Continuously monitoring the ECG signals over hours combined with activity status is very important for preventing cardiovascular diseases. A traditional ECG holter is often inconvenient to carry because it has many electrodes attached to the chest and because it is heavy. This work proposes a wearable, low power context-aware ECG monitoring system integrated built-in kinetic sensors of the smartphone with a self-designed ECG sensor. The wearable ECG sensor is comprised of a fully integrated analog front-end (AFE), a commercial micro control unit (MCU), a secure digital (SD) card, and a Bluetooth module. The whole sensor is very small with a size of only 58 × 50 × 10 mm for wearable monitoring application due to the AFE design, and the total power dissipation in a full round of ECG acquisition is only 12.5 mW. With the help of built-in kinetic sensors of the smartphone, the proposed system can compute and recognize user's physical activity, and thus provide context-aware information for the continuous ECG monitoring. The experimental results demonstrated the performance of proposed system in improving diagnosis accuracy for arrhythmias and identifying the most common abnormal ECG patterns in different activities. In conclusion, we provide a wearable, accurate and energy-efficient system for long-term and context-aware ECG monitoring without any extra cost on kinetic sensor design but with the help of the widespread smartphone.

Development of Sensors for Ceramic Components in Advanced Propulsion Systems. Phase 2; Temperature Sensor Systems Evaluation

NASA Technical Reports Server (NTRS)

Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

1994-01-01

The 'development of sensors for ceramic components in advanced propulsion systems' program is divided into two phases. The objectives of Phase 1 were to analyze, evaluate and recommend sensor concepts for the measurement of surface temperature, strain and heat flux on ceramic components for advanced propulsion systems. The results of this effort were previously published in NASA CR-182111. As a result of Phase 1, three approaches were recommended for further development: pyrometry, thin-film sensors, and thermographic phosphors. The objective of Phase 2 were to fabricate and conduct laboratory demonstration tests of these systems. Six materials, mutually agreed upon by NASA and Pratt & Whitney, were investigated under this program. This report summarizes the Phase 2 effort and provides conclusions and recommendations for each of the categories evaluated.

Smart sensor systems for human health breath monitoring applications.

PubMed

Hunter, G W; Xu, J C; Biaggi-Labiosa, A M; Laskowski, D; Dutta, P K; Mondal, S P; Ward, B J; Makel, D B; Liu, C C; Chang, C W; Dweik, R A

2011-09-01

Breath analysis techniques offer a potential revolution in health care diagnostics, especially if these techniques can be brought into standard use in the clinic and at home. The advent of microsensors combined with smart sensor system technology enables a new generation of sensor systems with significantly enhanced capabilities and minimal size, weight and power consumption. This paper discusses the microsensor/smart sensor system approach and provides a summary of efforts to migrate this technology into human health breath monitoring applications. First, the basic capability of this approach to measure exhaled breath associated with exercise physiology is demonstrated. Building from this foundation, the development of a system for a portable asthma home health care system is described. A solid-state nitric oxide (NO) sensor for asthma monitoring has been identified, and efforts are underway to miniaturize this NO sensor technology and integrate it into a smart sensor system. It is concluded that base platform microsensor technology combined with smart sensor systems can address the needs of a range of breath monitoring applications and enable new capabilities for healthcare.

Allegany Ballistics Lab: sensor test target system

NASA Astrophysics Data System (ADS)

Eaton, Deran S.

2011-06-01

Leveraging the Naval Surface Warfare Center, Indian Head Division's historical experience in weapon simulation, Naval Sea Systems Command commissioned development of a remote-controlled, digitally programmable Sensor Test Target as part of a modern, outdoor hardware-in-the-loop test system for ordnance-related guidance, navigation and control systems. The overall Target system design invokes a sciences-based, "design of automated experiments" approach meant to close the logistical distance between sensor engineering and developmental T&E in outdoor conditions over useful real world distances. This enables operating modes that employ broad spectrum electromagnetic energy in many a desired combination, variably generated using a Jet Engine Simulator, a multispectral infrared emitter array, optically enhanced incandescent Flare Simulators, Emitter/Detector mounts, and an RF corner reflector kit. As assembled, the recently tested Sensor Test Target prototype being presented can capably provide a full array of useful RF and infrared target source simulations for RDT&E use with developmental and existing sensors. Certain Target technologies are patent pending, with potential spinoffs in aviation, metallurgy and biofuels processing, while others are variations on well-established technology. The Sensor Test Target System is planned for extended installation at Allegany Ballistics Laboratory (Rocket Center, WV).

Optimal Sensor Selection for Health Monitoring Systems

NASA Technical Reports Server (NTRS)

Santi, L. Michael; Sowers, T. Shane; Aguilar, Robert B.

2005-01-01

Sensor data are the basis for performance and health assessment of most complex systems. Careful selection and implementation of sensors is critical to enable high fidelity system health assessment. A model-based procedure that systematically selects an optimal sensor suite for overall health assessment of a designated host system is described. This procedure, termed the Systematic Sensor Selection Strategy (S4), was developed at NASA John H. Glenn Research Center in order to enhance design phase planning and preparations for in-space propulsion health management systems (HMS). Information and capabilities required to utilize the S4 approach in support of design phase development of robust health diagnostics are outlined. A merit metric that quantifies diagnostic performance and overall risk reduction potential of individual sensor suites is introduced. The conceptual foundation for this merit metric is presented and the algorithmic organization of the S4 optimization process is described. Representative results from S4 analyses of a boost stage rocket engine previously under development as part of NASA's Next Generation Launch Technology (NGLT) program are presented.

Effects of Activation Energy to Transient Response of Semiconductor Gas Sensor

NASA Astrophysics Data System (ADS)

Fujimoto, Akira; Ohtani, Tatsuki

The smell classifiable gas sensor will be desired for many applications such as gas detection alarms, process controls for food production and so on. We have tried to realize the sensor using transient responses of semiconductor gas sensor consisting of tin dioxide and pointed out that the sensor gave us different transient responses for kinds of gas. Results of model calculation showed the activation energy of chemical reaction on the sensor surface strongly depended on the transient response. We tried to estimate the activation energies by molecular orbital calculation with SnO2 Cluster. The results show that there is a liner relationship between the gradient of the transient responses and activation energies for carboxylic and alcoholic gases. Transient response will be predicted from activation energy in the same kind of gas and the smell discrimination by single semiconductor gas sensor will be realized by this relationship.

Vertebrate gravity sensors as dynamic systems

NASA Technical Reports Server (NTRS)

Ross, M. D.

1985-01-01

This paper considers verterbrate gravity receptors as dynamic sensors. That is, it is hypothesized that gravity is a constant force to which an acceleration-sensing system would readily adapt. Premises are considered in light of the presence of kinocilia on hair cells of vertebrate gravity sensors; differences in loading of the sensors among species; and of possible reduction in loading by inclusion of much organic material in otoconia. Moreover, organic-inorganic interfaces may confer a piezoelectric property upon otoconia, which increase the sensitivity of the sensory system to small accelerations. Comparisons with man-made accelerometers are briefly taken up.

Chemical sensor system

DOEpatents

Darrow, Christopher B.; Satcher, Jr., Joe H.; Lane, Stephen M.; Lee, Abraham P.; Wang, Amy W.

2002-01-01

An implantable chemical sensor system for medical applications is described which permits selective recognition of an analyte using an expandable biocompatible sensor, such as a polymer, that undergoes a dimensional change in the presence of the analyte. The expandable polymer is incorporated into an electronic circuit component that changes its properties (e.g., frequency) when the polymer changes dimension. As the circuit changes its characteristics, an external interrogator transmits a signal transdermally to the transducer, and the concentration of the analyte is determined from the measured changes in the circuit. This invention may be used for minimally invasive monitoring of blood glucose levels in diabetic patients.

Onboard Image Processing System for Hyperspectral Sensor

PubMed Central

Hihara, Hiroki; Moritani, Kotaro; Inoue, Masao; Hoshi, Yoshihiro; Iwasaki, Akira; Takada, Jun; Inada, Hitomi; Suzuki, Makoto; Seki, Taeko; Ichikawa, Satoshi; Tanii, Jun

2015-01-01

Onboard image processing systems for a hyperspectral sensor have been developed in order to maximize image data transmission efficiency for large volume and high speed data downlink capacity. Since more than 100 channels are required for hyperspectral sensors on Earth observation satellites, fast and small-footprint lossless image compression capability is essential for reducing the size and weight of a sensor system. A fast lossless image compression algorithm has been developed, and is implemented in the onboard correction circuitry of sensitivity and linearity of Complementary Metal Oxide Semiconductor (CMOS) sensors in order to maximize the compression ratio. The employed image compression method is based on Fast, Efficient, Lossless Image compression System (FELICS), which is a hierarchical predictive coding method with resolution scaling. To improve FELICS’s performance of image decorrelation and entropy coding, we apply a two-dimensional interpolation prediction and adaptive Golomb-Rice coding. It supports progressive decompression using resolution scaling while still maintaining superior performance measured as speed and complexity. Coding efficiency and compression speed enlarge the effective capacity of signal transmission channels, which lead to reducing onboard hardware by multiplexing sensor signals into a reduced number of compression circuits. The circuitry is embedded into the data formatter of the sensor system without adding size, weight, power consumption, and fabrication cost. PMID:26404281

Transparent Stretchable Self-Powered Patchable Sensor Platform with Ultrasensitive Recognition of Human Activities.

PubMed

Hwang, Byeong-Ung; Lee, Ju-Hyuck; Trung, Tran Quang; Roh, Eun; Kim, Do-Il; Kim, Sang-Woo; Lee, Nae-Eung

2015-09-22

Monitoring of human activities can provide clinically relevant information pertaining to disease diagnostics, preventive medicine, care for patients with chronic diseases, rehabilitation, and prosthetics. The recognition of strains on human skin, induced by subtle movements of muscles in the internal organs, such as the esophagus and trachea, and the motion of joints, was demonstrated using a self-powered patchable strain sensor platform, composed on multifunctional nanocomposites of low-density silver nanowires with a conductive elastomer of poly(3,4-ethylenedioxythiophene):polystyrenesulfonate/polyurethane, with high sensitivity, stretchability, and optical transparency. The ultra-low-power consumption of the sensor, integrated with both a supercapacitor and a triboelectric nanogenerator into a single transparent stretchable platform based on the same nanocomposites, results in a self-powered monitoring system for skin strain. The capability of the sensor to recognize a wide range of strain on skin has the potential for use in new areas of invisible stretchable electronics for human monitoring. A new type of transparent, stretchable, and ultrasensitive strain sensor based on a AgNW/PEDOT:PSS/PU nanocomposite was developed. The concept of a self-powered patchable sensor system integrated with a supercapacitor and a triboelectric nanogenerator that can be used universally as an autonomous invisible sensor system was used to detect the wide range of strain on human skin.

Development of chipless, wireless current sensor system based on giant magnetoimpedance magnetic sensor and surface acoustic wave transponder.

PubMed

Kondalkar, Vijay V; Li, Xiang; Park, Ikmo; Yang, Sang Sik; Lee, Keekeun

2018-02-05

A chipless, wireless current sensor system was developed using a giant magnetoimpedance (GMI) magnetic sensor and one-port surface acoustic wave (SAW) reflective delay line for real-time power monitoring in a current-carrying conductor. The GMI sensor has a high-quality crystalline structure in each layer, which contributes to a high sensitivity and good linearity in a magnetic field of 3-16 Oe. A 400 MHz RF energy generated from the interdigital transducer (IDT)-type reflector on the one-port SAW delay line was used as an activation source for the GMI magnetic sensor. The one-port SAW delay line replaces the presently existing transceiver system, which is composed of thousands of transistors, thus enabling chipless and wireless operation. We confirmed a large variation in the amplitude of the SAW reflection peak with a change in the impedance of the GMI sensor caused by the current flow through the conductor. Good linearity and sensitivity of ~0.691 dB/A were observed for currents in the range 1-12 A. Coupling of Mode (COM) modeling and impedance matching analysis were also performed to predict the device performance in advance and these were compared with the experimental results.

Evaluation of a Microbial Sensor as a Tool for Antimicrobial Activity Test of Cosmetic Preservatives.

PubMed

Gomyo, Hideyuki; Ookawa, Masaki; Oshibuchi, Kota; Sugamura, Yuriko; Hosokawa, Masahito; Shionoiri, Nozomi; Maeda, Yoshiaki; Matsunaga, Tadashi; Tanaka, Tsuyoshi

2015-01-01

For high-throughput screening of novel cosmetic preservatives, a rapid and simple assay to evaluate the antimicrobial activities should be developed because the conventional agar dilution method is time-consuming and labor-intensive. To address this issue, we evaluated a microbial sensor as a tool for rapid antimicrobial activity testing. The sensor consists of an oxygen electrode and a filter membrane that holds the test microorganisms, Staphylococcus aureus and Candida albicans. The antimicrobial activity of the tested cosmetic preservative was evaluated by measuring the current increases corresponding to the decreases in oxygen consumption in the microbial respiration. The current increases detected by the sensor showed positive correlation to the concentrations of two commercially used preservatives, chlorphenesin and 2-phenoxyethanol. The same tendency was also observed when a model cosmetic product was used as a preservative solvent, indicating the feasibility in practical use. Furthermore, the microbial sensor and microfluidic flow-cell was assembled to achieve sequential measurements. The sensor system presented in this study could be useful in large-scale screening experiments.

The tsunami service bus, an integration platform for heterogeneous sensor systems

NASA Astrophysics Data System (ADS)

Haener, R.; Waechter, J.; Kriegel, U.; Fleischer, J.; Mueller, S.

2009-04-01

components remain unchanged, components can be maintained and evolved independently on each other and service functionality as a whole can be reused. In GITEWS the functional integration pattern was adopted by applying the principles of an Enterprise Service Bus (ESB) as a backbone. Four services provided by the so called Tsunami Service Bus (TSB) which are essential for early warning systems are realized compliant to services specified within the Sensor Web Enablement (SWE) initiative of the Open Geospatial Consortium (OGC). 3. ARCHITECTURE The integration platform was developed to access proprietary, heterogeneous sensor data and to provide them in a uniform manner for further use. Its core, the TSB provides both a messaging-backbone and -interfaces on the basis of a Java Messaging Service (JMS). The logical architecture of GITEWS consists of four independent layers: • A resource layer where physical or virtual sensors as well as data or model storages provide relevant measurement-, event- and analysis-data: Utilizable for the TSB are any kind of data. In addition to sensors databases, model data and processing applications are adopted. SWE specifies encoding both to access and to describe these data in a comprehensive way: 1. Sensor Model Language (SensorML): Standardized description of sensors and sensor data 2. Observations and Measurements (O&M): Model and encoding of sensor measurements • A service layer to collect and conduct data from heterogeneous and proprietary resources and provide them via standardized interfaces: The TSB enables interaction with sensors via the following services: 1. Sensor Observation Service (SOS): Standardized access to sensor data 2. Sensor Planning Service (SPS): Controlling of sensors and sensor networks 3. Sensor Alert Service (SAS): Active sending of data if defined events occur 4. Web Notification Service (WNS): Conduction of asynchronous dialogues between services • An orchestration layer where atomic services are composed and

System approach to distributed sensor management

NASA Astrophysics Data System (ADS)

Mayott, Gregory; Miller, Gordon; Harrell, John; Hepp, Jared; Self, Mid

2010-04-01

Since 2003, the US Army's RDECOM CERDEC Night Vision Electronic Sensor Directorate (NVESD) has been developing a distributed Sensor Management System (SMS) that utilizes a framework which demonstrates application layer, net-centric sensor management. The core principles of the design support distributed and dynamic discovery of sensing devices and processes through a multi-layered implementation. This results in a sensor management layer that acts as a System with defined interfaces for which the characteristics, parameters, and behaviors can be described. Within the framework, the definition of a protocol is required to establish the rules for how distributed sensors should operate. The protocol defines the behaviors, capabilities, and message structures needed to operate within the functional design boundaries. The protocol definition addresses the requirements for a device (sensors or processes) to dynamically join or leave a sensor network, dynamically describe device control and data capabilities, and allow dynamic addressing of publish and subscribe functionality. The message structure is a multi-tiered definition that identifies standard, extended, and payload representations that are specifically designed to accommodate the need for standard representations of common functions, while supporting the need for feature-based functions that are typically vendor specific. The dynamic qualities of the protocol enable a User GUI application the flexibility of mapping widget-level controls to each device based on reported capabilities in real-time. The SMS approach is designed to accommodate scalability and flexibility within a defined architecture. The distributed sensor management framework and its application to a tactical sensor network will be described in this paper.

Ultrasensitive surveillance of sensors and processes

DOEpatents

Wegerich, Stephan W.; Jarman, Kristin K.; Gross, Kenneth C.

2001-01-01

A method and apparatus for monitoring a source of data for determining an operating state of a working system. The method includes determining a sensor (or source of data) arrangement associated with monitoring the source of data for a system, activating a method for performing a sequential probability ratio test if the data source includes a single data (sensor) source, activating a second method for performing a regression sequential possibility ratio testing procedure if the arrangement includes a pair of sensors (data sources) with signals which are linearly or non-linearly related; activating a third method for performing a bounded angle ratio test procedure if the sensor arrangement includes multiple sensors and utilizing at least one of the first, second and third methods to accumulate sensor signals and determining the operating state of the system.

Ultrasensitive surveillance of sensors and processes

DOEpatents

Wegerich, Stephan W.; Jarman, Kristin K.; Gross, Kenneth C.

1999-01-01

A method and apparatus for monitoring a source of data for determining an operating state of a working system. The method includes determining a sensor (or source of data) arrangement associated with monitoring the source of data for a system, activating a method for performing a sequential probability ratio test if the data source includes a single data (sensor) source, activating a second method for performing a regression sequential possibility ratio testing procedure if the arrangement includes a pair of sensors (data sources) with signals which are linearly or non-linearly related; activating a third method for performing a bounded angle ratio test procedure if the sensor arrangement includes multiple sensors and utilizing at least one of the first, second and third methods to accumulate sensor signals and determining the operating state of the system.

EDITORIAL: Sensors and sensing systems

NASA Astrophysics Data System (ADS)

Dewhurst, Richard; Tian, Gui Yun

2008-02-01

Sensors are very important for measurement science and technology. They serve as a vital component in new measurement techniques and instrumentation systems. Key qualities of a good sensor system are high resolution, high reliability, low cost, appropriate output for a given input (good sensitivity), rapid response time, small random error in results, and small systematic error. Linearity is also useful, but with the advent of lookup tables and software, it is not as important as it used to be. In the last several years, considerable effort around the world has been devoted to a wide range of sensors from nanoscale sensors to sensor networks. Collectively, these vast and multidisciplinary efforts are developing important technological roadmaps to futuristic sensors with new modalities, significantly enhanced effectiveness and integrated functionality (data processing, computation, decision making and communications). When properly organized, they will have important relevance to life science and security applications, e.g. the sensing and monitoring of chemical, biological, radiological and explosive threats. A special feature in this issue takes a snapshot of some recent developments that were first presented at an international conference, the 2007 IEEE International Conference on Networking, Sensing and Control (ICNSC). The conference discussed recent developments, from which a few papers have since been brought together in this special feature. Gas sensing for environmental monitoring remains a topical subject, and two papers deal with this issue. One is concerned with the exploitation of nanostructured Au-doped cobalt oxyhydroxide-based carbon monoxide sensors for fire detection at its earlier stages (Zhuiykov and Dowling), whilst another examines the role of oxygen in high temperature hydrogen sulfide detection using MISiC sensors (Weng et al). Again for environmental monitoring, another paper deals with accurate sound source localization in a reverberant

Optimization of wireless Bluetooth sensor systems.

PubMed

Lonnblad, J; Castano, J; Ekstrom, M; Linden, M; Backlund, Y

2004-01-01

Within this study, three different Bluetooth sensor systems, replacing cables for transmission of biomedical sensor data, have been designed and evaluated. The three sensor architectures are built on 1-, 2- and 3-chip solutions and depending on the monitoring situation and signal character, different solutions are optimal. Essential parameters for all systems have been low physical weight and small size, resistance to interference and interoperability with other technologies as global- or local networks, PC's and mobile phones. Two different biomedical input signals, ECG and PPG (photoplethysmography), have been used to evaluate the three solutions. The study shows that it is possibly to continuously transmit an analogue signal. At low sampling rates and slowly varying parameters, as monitoring the heart rate with PPG, the 1-chip solution is the most suitable, offering low power consumption and thus a longer battery lifetime or a smaller battery, minimizing the weight of the sensor system. On the other hand, when a higher sampling rate is required, as an ECG, the 3-chip architecture, with a FPGA or micro-controller, offers the best solution and performance. Our conclusion is that Bluetooth might be useful in replacing cables of medical monitoring systems.

MicroSensors Systems: detection of a dismounted threat

NASA Astrophysics Data System (ADS)

Davis, Bill; Berglund, Victor; Falkofske, Dwight; Krantz, Brian

2005-05-01

The Micro Sensor System (MSS) is a layered sensor network with the goal of detecting dismounted threats approaching high value assets. A low power unattended ground sensor network is dependant on a network protocol for efficiency in order to minimize data transmissions after network establishment. The reduction of network 'chattiness' is a primary driver for minimizing power consumption and is a factor in establishing a low probability of detection and interception. The MSS has developed a unique protocol to meet these challenges. Unattended ground sensor systems are most likely dependant on batteries for power which due to size determines the ability of the sensor to be concealed after placement. To minimize power requirements, overcome size limitations, and maintain a low system cost the MSS utilizes advanced manufacturing processes know as Fluidic Self-Assembly and Chip Scale Packaging. The type of sensing element and the ability to sense various phenomenologies (particularly magnetic) at ranges greater than a few meters limits the effectiveness of a system. The MicroSensor System will overcome these limitations by deploying large numbers of low cost sensors, which is made possible by the advanced manufacturing process used in production of the sensors. The MSS program will provide unprecedented levels of real-time battlefield information which greatly enhances combat situational awareness when integrated with the existing Command, Control, Communications, Computers, Intelligence, Surveillance and Reconnaissance (C4ISR) infrastructure. This system will provide an important boost to realizing the information dominant, network-centric objective of Joint Vision 2020.

A Tactile Sensor Network System Using a Multiple Sensor Platform with a Dedicated CMOS-LSI for Robot Applications.

PubMed

Shao, Chenzhong; Tanaka, Shuji; Nakayama, Takahiro; Hata, Yoshiyuki; Bartley, Travis; Nonomura, Yutaka; Muroyama, Masanori

2017-08-28

Robot tactile sensation can enhance human-robot communication in terms of safety, reliability and accuracy. The final goal of our project is to widely cover a robot body with a large number of tactile sensors, which has significant advantages such as accurate object recognition, high sensitivity and high redundancy. In this study, we developed a multi-sensor system with dedicated Complementary Metal-Oxide-Semiconductor (CMOS) Large-Scale Integration (LSI) circuit chips (referred to as "sensor platform LSI") as a framework of a serial bus-based tactile sensor network system. The sensor platform LSI supports three types of sensors: an on-chip temperature sensor, off-chip capacitive and resistive tactile sensors, and communicates with a relay node via a bus line. The multi-sensor system was first constructed on a printed circuit board to evaluate basic functions of the sensor platform LSI, such as capacitance-to-digital and resistance-to-digital conversion. Then, two kinds of external sensors, nine sensors in total, were connected to two sensor platform LSIs, and temperature, capacitive and resistive sensing data were acquired simultaneously. Moreover, we fabricated flexible printed circuit cables to demonstrate the multi-sensor system with 15 sensor platform LSIs operating simultaneously, which showed a more realistic implementation in robots. In conclusion, the multi-sensor system with up to 15 sensor platform LSIs on a bus line supporting temperature, capacitive and resistive sensing was successfully demonstrated.

Development and evaluation of a lightweight sensor system ...

EPA Pesticide Factsheets

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 with diameter of 2.5 µm or less (PM2.5), and volatile organic compounds (VOCs). This extended abstract, intended for oral presentation or poster presentation at this summer's AWMA conference, presents some of the first verification data from laboratory and burn calibration of a newly developed sensor and sampler system for ground and aerial sampling.

Impact of Sensor Misplacement on Dynamic Time Warping Based Human Activity Recognition using Wearable Computers.

PubMed

Kale, Nimish; Lee, Jaeseong; Lotfian, Reza; Jafari, Roozbeh

2012-10-01

Daily living activity monitoring is important for early detection of the onset of many diseases and for improving quality of life especially in elderly. A wireless wearable network of inertial sensor nodes can be used to observe daily motions. Continuous stream of data generated by these sensor networks can be used to recognize the movements of interest. Dynamic Time Warping (DTW) is a widely used signal processing method for time-series pattern matching because of its robustness to variations in time and speed as opposed to other template matching methods. Despite this flexibility, for the application of activity recognition, DTW can only find the similarity between the template of a movement and the incoming samples, when the location and orientation of the sensor remains unchanged. Due to this restriction, small sensor misplacements can lead to a decrease in the classification accuracy. In this work, we adopt DTW distance as a feature for real-time detection of human daily activities like sit to stand in the presence of sensor misplacement. To measure this performance of DTW, we need to create a large number of sensor configurations while the sensors are rotated or misplaced. Creating a large number of closely spaced sensors is impractical. To address this problem, we use the marker based optical motion capture system and generate simulated inertial sensor data for different locations and orientations on the body. We study the performance of the DTW under these conditions to determine the worst-case sensor location variations that the algorithm can accommodate.

Active imaging system performance model for target acquisition

NASA Astrophysics Data System (ADS)

Espinola, Richard L.; Teaney, Brian; Nguyen, Quang; Jacobs, Eddie L.; Halford, Carl E.; Tofsted, David H.

2007-04-01

The U.S. Army RDECOM CERDEC Night Vision & Electronic Sensors Directorate has developed a laser-range-gated imaging system performance model for the detection, recognition, and identification of vehicle targets. The model is based on the established US Army RDECOM CERDEC NVESD sensor performance models of the human system response through an imaging system. The Java-based model, called NVLRG, accounts for the effect of active illumination, atmospheric attenuation, and turbulence effects relevant to LRG imagers, such as speckle and scintillation, and for the critical sensor and display components. This model can be used to assess the performance of recently proposed active SWIR systems through various trade studies. This paper will describe the NVLRG model in detail, discuss the validation of recent model components, present initial trade study results, and outline plans to validate and calibrate the end-to-end model with field data through human perception testing.

Ferroelectric thin-film active sensors for structural health monitoring

NASA Astrophysics Data System (ADS)

Lin, Bin; Giurgiutiu, Victor; Yuan, Zheng; Liu, Jian; Chen, Chonglin; Jiang, Jiechao; Bhalla, Amar S.; Guo, Ruyan

2007-04-01

Piezoelectric wafer active sensors (PWAS) have been proven a valuable tool in structural health monitoring. Piezoelectric wafer active sensors are able to send and receive guided Lamb/Rayleigh waves that scan the structure and detect the presence of incipient cracks and structural damage. In-situ thin-film active sensor deposition can eliminate the bonding layer to improve the durability issue and reduce the acoustic impedance mismatch. Ferroelectric thin films have been shown to have piezoelectric properties that are close to those of single-crystal ferroelectrics but the fabrication of ferroelectric thin films on structural materials (steel, aluminum, titanium, etc.) has not been yet attempted. In this work, in-situ fabrication method of piezoelectric thin-film active sensors arrays was developed using the nano technology approach. Specification for the piezoelectric thin-film active sensors arrays was based on electro-mechanical-acoustical model. Ferroelectric BaTiO3 (BTO) thin films were successfully deposited on Ni tapes by pulsed laser deposition under the optimal synthesis conditions. Microstructural studies by X-ray diffractometer and transmission electron microscopy reveal that the as-grown BTO thin films have the nanopillar structures with an average size of approximately 80 nm in diameter and the good interface structures with no inter-diffusion or reaction. The dielectric and ferroelectric property measurements exhibit that the BTO films have a relatively large dielectric constant, a small dielectric loss, and an extremely large piezoelectric response with a symmetric hysteresis loop. The research objective is to develop the fabrication and optimum design of thin-film active sensor arrays for structural health monitoring applications. The short wavelengths of the micro phased arrays will permit the phased-array imaging of smaller parts and smaller damage than is currently not possible with existing technology.

Active thermal isolation for temperature responsive sensors

NASA Technical Reports Server (NTRS)

Martinson, Scott D. (Inventor); Gray, David L. (Inventor); Carraway, Debra L. (Inventor); Reda, Daniel C. (Inventor)

1994-01-01

The detection of flow transition between laminar and turbulent flow and of shear stress or skin friction of airfoils is important in basic research for validation of airfoil theory and design. These values are conventionally measured using hot film nickel sensors deposited on a polyimide substrate. The substrate electrically insulates the sensor and underlying airfoil but is prevented from thermally isolating the sensor by thickness constraints necessary to avoid flow contamination. Proposed heating of the model surface is difficult to control, requires significant energy expenditures, and may alter the basic flow state of the airfoil. A temperature responsive sensor is located in the airflow over the specified surface of a body and is maintained at a constant temperature. An active thermal isolator is located between this temperature responsive sensor and the specific surface of the body. The total thickness of the isolator and sensor avoid any contamination of the flow. The temperature of this isolator is controlled to reduce conductive heat flow from the temperature responsive sensor to the body. This temperature control includes (1) operating the isolator at the same temperature as the constant temperature of the sensor; and (2) establishing a fixed boundary temperature which is either less than or equal to, or slightly greater than the sensor constant temperature. The present invention accordingly thermally isolates a temperature responsive sensor in an energy efficient, controllable manner while avoiding any contamination of the flow.

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

Semiautonomous Avionics-and-Sensors System for a UAV

NASA Technical Reports Server (NTRS)

Shams, Qamar

2006-01-01

Unmanned Aerial Vehicles (UAVs) autonomous or remotely controlled pilotless aircraft have been recently thrust into the spotlight for military applications, for homeland security, and as test beds for research. In addition to these functions, there are many space applications in which lightweight, inexpensive, small UAVS can be used e.g., to determine the chemical composition and other qualities of the atmospheres of remote planets. Moreover, on Earth, such UAVs can be used to obtain information about weather in various regions; in particular, they can be used to analyze wide-band acoustic signals to aid in determining the complex dynamics of movement of hurricanes. The Advanced Sensors and Electronics group at Langley Research Center has developed an inexpensive, small, integrated avionics-and-sensors system to be installed in a UAV that serves two purposes. The first purpose is to provide flight data to an AI (Artificial Intelligence) controller as part of an autonomous flight-control system. The second purpose is to store data from a subsystem of distributed MEMS (microelectromechanical systems) sensors. Examples of these MEMS sensors include humidity, temperature, and acoustic sensors, plus chemical sensors for detecting various vapors and other gases in the environment. The critical sensors used for flight control are a differential- pressure sensor that is part of an apparatus for determining airspeed, an absolute-pressure sensor for determining altitude, three orthogonal accelerometers for determining tilt and acceleration, and three orthogonal angular-rate detectors (gyroscopes). By using these eight sensors, it is possible to determine the orientation, height, speed, and rates of roll, pitch, and yaw of the UAV. This avionics-and-sensors system is shown in the figure. During the last few years, there has been rapid growth and advancement in the technological disciplines of MEMS, of onboard artificial-intelligence systems, and of smaller, faster, and

Optoelectronic Sensor System for Guidance in Docking

NASA Technical Reports Server (NTRS)

Howard, Richard T.; Bryan, Thomas C.; Book, Michael L.; Jackson, John L.

2004-01-01

The Video Guidance Sensor (VGS) system is an optoelectronic sensor that provides automated guidance between two vehicles. In the original intended application, the two vehicles would be spacecraft docking together, but the basic principles of design and operation of the sensor are applicable to aircraft, robots, vehicles, or other objects that may be required to be aligned for docking, assembly, resupply, or precise separation. The system includes a sensor head containing a monochrome charge-coupled- device video camera and pulsed laser diodes mounted on the tracking vehicle, and passive reflective targets on the tracked vehicle. The lasers illuminate the targets, and the resulting video images of the targets are digitized. Then, from the positions of the digitized target images and known geometric relationships among the targets, the relative position and orientation of the vehicles are computed. As described thus far, the VGS system is based on the same principles as those of the system described in "Improved Video Sensor System for Guidance in Docking" (MFS-31150), NASA Tech Briefs, Vol. 21, No. 4 (April 1997), page 9a. However, the two systems differ in the details of design and operation. The VGS system is designed to operate with the target completely visible within a relative-azimuth range of +/-10.5deg and a relative-elevation range of +/-8deg. The VGS acquires and tracks the target within that field of view at any distance from 1.0 to 110 m and at any relative roll, pitch, and/or yaw angle within +/-10deg. The VGS produces sets of distance and relative-orientation data at a repetition rate of 5 Hz. The software of this system also accommodates the simultaneous operation of two sensors for redundancy

CMOS Active-Pixel Image Sensor With Simple Floating Gates

NASA Technical Reports Server (NTRS)

Fossum, Eric R.; Nakamura, Junichi; Kemeny, Sabrina E.

1996-01-01

Experimental complementary metal-oxide/semiconductor (CMOS) active-pixel image sensor integrated circuit features simple floating-gate structure, with metal-oxide/semiconductor field-effect transistor (MOSFET) as active circuit element in each pixel. Provides flexibility of readout modes, no kTC noise, and relatively simple structure suitable for high-density arrays. Features desirable for "smart sensor" applications.

Distributed estimation for adaptive sensor selection in wireless sensor networks

NASA Astrophysics Data System (ADS)

Mahmoud, Magdi S.; Hassan Hamid, Matasm M.

2014-05-01

Wireless sensor networks (WSNs) are usually deployed for monitoring systems with the distributed detection and estimation of sensors. Sensor selection in WSNs is considered for target tracking. A distributed estimation scenario is considered based on the extended information filter. A cost function using the geometrical dilution of precision measure is derived for active sensor selection. A consensus-based estimation method is proposed in this paper for heterogeneous WSNs with two types of sensors. The convergence properties of the proposed estimators are analyzed under time-varying inputs. Accordingly, a new adaptive sensor selection (ASS) algorithm is presented in which the number of active sensors is adaptively determined based on the absolute local innovations vector. Simulation results show that the tracking accuracy of the ASS is comparable to that of the other algorithms.

Circuits and Systems for Low-Power Miniaturized Wireless Sensors

NASA Astrophysics Data System (ADS)

Nagaraju, Manohar

The field of electronic sensors has witnessed a tremendous growth over the last decade particularly with the proliferation of mobile devices. New applications in Internet of Things (IoT), wearable technology, are further expected to fuel the demand for sensors from current numbers in the range of billions to trillions in the next decade. The main challenges for a trillion sensors are continued miniaturization, low-cost and large-scale manufacturing process, and low power consumption. Traditional integration and circuit design techniques in sensor systems are not suitable for applications in smart dust, IoT etc. The first part of this thesis demonstrates an example sensor system for biosignal recording and illustrates the tradeoffs in the design of low-power miniaturized sensors. The different components of the sensor system are integrated at the board level. The second part of the thesis demonstrates fully integrated sensors that enable extreme miniaturization of a sensing system with the sensor element, processing circuitry, a frequency reference for communication and the communication circuitry in a single hermetically sealed die. Design techniques to reduce the power consumption of the sensor interface circuitry at the architecture and circuit level are demonstrated. The principles are used to design sensors for two of the most common physical variables, mass and pressure. A low-power wireless mass and pressure sensor suitable for a wide variety of biological/chemical sensing applications and Tire Pressure Monitoring Systems (TPMS) respectively are demonstrated. Further, the idea of using high-Q resonators for a Voltage Controlled Oscillator (VCO) is proposed and a low-noise, wide bandwidth FBAR-based VCO is presented.

Electric fish as natural models for technical sensor systems

NASA Astrophysics Data System (ADS)

von der Emde, Gerhard; Bousack, Herbert; Huck, Christina; Mayekar, Kavita; Pabst, Michael; Zhang, Yi

2009-05-01

Instead of vision, many animals use alternative senses for object detection. Weakly electric fish employ "active electrolocation", during which they discharge an electric organ emitting electrical current pulses (electric organ discharges, EOD). Local EODs are sensed by electroreceptors in the fish's skin, which respond to changes of the signal caused by nearby objects. Fish can gain information about attributes of an object, such as size, shape, distance, and complex impedance. When close to the fish, each object projects an 'electric image' onto the fish's skin. In order to get information about an object, the fish has to analyze the object's electric image by sampling its voltage distribution with the electroreceptors. We now know a great deal about the mechanisms the fish use to gain information about objects in their environment. Inspired by the remarkable capabilities of weakly electric fish in detecting and recognizing objects with their electric sense, we are designing technical sensor systems that can solve similar sensing problems. We applied the principles of active electrolocation to devices that produce electrical current pulses in water and simultaneously sense local current densities. Depending on the specific task, sensors can be designed which detect an object, localize it in space, determine its distance, and measure certain object properties such as material properties, thickness, or material faults. We present first experiments and FEM simulations on the optimal sensor arrangement regarding the sensor requirements e. g. localization of objects or distance measurements. Different methods of the sensor read-out and signal processing are compared.

Multi-sensor Navigation System Design

DOT National Transportation Integrated Search

1971-03-01

This report treats the design of naviggation systems that collect data from two or more on-board measurement subsystems and precess this data in an on-board computer. Such systems are called Multi-sensor Navigation Systems. : The design begins with t...

Flexible piezoelectric nanogenerator in wearable self-powered active sensor for respiration and healthcare monitoring

NASA Astrophysics Data System (ADS)

Liu, Z.; Zhang, S.; Jin, Y. M.; Ouyang, H.; Zou, Y.; Wang, X. X.; Xie, L. X.; Li, Z.

2017-06-01

A wearable self-powered active sensor for respiration and healthcare monitoring was fabricated based on a flexible piezoelectric nanogenerator. An electrospinning poly(vinylidene fluoride) thin film on silicone substrate was polarized to fabricate the flexible nanogenerator and its electrical property was measured. When periodically stretched by a linear motor, the flexible piezoelectric nanogenerator generated an output open-circuit voltage and short-circuit current of up to 1.5 V and 400 nA, respectively. Through integration with an elastic bandage, a wearable self-powered sensor was fabricated and used to monitor human respiration, subtle muscle movement, and voice recognition. As respiration proceeded, the electrical output signals of the sensor corresponded to the signals measured by a physiological signal recording system with good reliability and feasibility. This self-powered, wearable active sensor has significant potential for applications in pulmonary function evaluation, respiratory monitoring, and detection of gesture and vocal cord vibration for the personal healthcare monitoring of disabled or paralyzed patients.

A civil structural monitoring system based on fiber grating sensors

NASA Astrophysics Data System (ADS)

Zhang, Yan; Cai, Haiwen; Pastore, Robert; Ju, Jing; Zeng, Debing; Yin, Zhifan; Cui, Hong-Liang

2003-08-01

Optical fiber sensors based on Fiber Bragg Grating (FBG) technology have found many applications in the area of civil structural monitoring systems, such as in bridge monitoring and maintenance. FBG sensors can measure the deformation, overload and cracks on bridge with a high sensitivity. In this paper we report on our recent work a structural monitoring system using FBG sensors. Basic theoretical background and design of the system is described here, including the light source, FBG sensors, demodulator sensors, signal detection and processing schemes. The system will be installed on a major arch bridge currently under construction in Shanghai, China for long-term in situ health monitoring. The system schematic arrangement on the bridge is introduced in brief. Simulation experiments in the laboratory were carried out to test the performance of FBG strain sensors. The sensor response shows excellent linearity against the strain imposed on it. Traffic and overload monitoring on bridge using FBG sensors is also discussed and planned for the near future.

Electro-optical rendezvous and docking sensors

NASA Technical Reports Server (NTRS)

Tubbs, David J.; Kesler, Lynn O.; Sirko, Robert J.

1991-01-01

Electro-optical sensors provide unique and critical functionality for space missions requiring rendezvous, docking, and berthing. McDonnell Douglas is developing a complete rendezvous and docking system for both manned and unmanned missions. This paper examines our sensor development and the systems and missions which benefit from rendezvous and docking sensors. Simulation results quantifying system performance improvements in key areas are given, with associated sensor performance requirements. A brief review of NASA-funded development activities and the current performance of electro-optical sensors for space applications is given. We will also describe current activities at McDonnell Douglas for a fully functional demonstration to address specific NASA mission needs.

Active Optical Sensors for Tree Stem Detection and Classification in Nurseries

PubMed Central

Garrido, Miguel; Perez-Ruiz, Manuel; Valero, Constantino; Gliever, Chris J.; Hanson, Bradley D.; Slaughter, David C.

2014-01-01

Active optical sensing (LIDAR and light curtain transmission) devices mounted on a mobile platform can correctly detect, localize, and classify trees. To conduct an evaluation and comparison of the different sensors, an optical encoder wheel was used for vehicle odometry and provided a measurement of the linear displacement of the prototype vehicle along a row of tree seedlings as a reference for each recorded sensor measurement. The field trials were conducted in a juvenile tree nursery with one-year-old grafted almond trees at Sierra Gold Nurseries, Yuba City, CA, United States. Through these tests and subsequent data processing, each sensor was individually evaluated to characterize their reliability, as well as their advantages and disadvantages for the proposed task. Test results indicated that 95.7% and 99.48% of the trees were successfully detected with the LIDAR and light curtain sensors, respectively. LIDAR correctly classified, between alive or dead tree states at a 93.75% success rate compared to 94.16% for the light curtain sensor. These results can help system designers select the most reliable sensor for the accurate detection and localization of each tree in a nursery, which might allow labor-intensive tasks, such as weeding, to be automated without damaging crops. PMID:24949638

Active optical sensors for tree stem detection and classification in nurseries.

PubMed

Garrido, Miguel; Perez-Ruiz, Manuel; Valero, Constantino; Gliever, Chris J; Hanson, Bradley D; Slaughter, David C

2014-06-19

Active optical sensing (LIDAR and light curtain transmission) devices mounted on a mobile platform can correctly detect, localize, and classify trees. To conduct an evaluation and comparison of the different sensors, an optical encoder wheel was used for vehicle odometry and provided a measurement of the linear displacement of the prototype vehicle along a row of tree seedlings as a reference for each recorded sensor measurement. The field trials were conducted in a juvenile tree nursery with one-year-old grafted almond trees at Sierra Gold Nurseries, Yuba City, CA, United States. Through these tests and subsequent data processing, each sensor was individually evaluated to characterize their reliability, as well as their advantages and disadvantages for the proposed task. Test results indicated that 95.7% and 99.48% of the trees were successfully detected with the LIDAR and light curtain sensors, respectively. LIDAR correctly classified, between alive or dead tree states at a 93.75% success rate compared to 94.16% for the light curtain sensor. These results can help system designers select the most reliable sensor for the accurate detection and localization of each tree in a nursery, which might allow labor-intensive tasks, such as weeding, to be automated without damaging crops.

Distributed Localization of Active Transmitters in a Wireless Sensor Network

DTIC Science & Technology

2012-03-01

Distributed Localization of Active Transmitters in a Wireless Sensor Network THESIS Oba L. Vincent, 2nd Lieutenant, USAF AFIT/GE/ENG/12-41 DEPARTMENT...protection in the United States. AFIT/GE/ENG/12-41 Distributed Localization of Active Transmitters in a Wireless Sensor Network THESIS Presented to the...Transmitters in a Wireless Sensor Network Oba L. Vincent, B.S.E.E. 2nd Lieutenant, USAF Approved: /signed/ 29 Feb 2012 Maj. Mark D. Silvius, Ph.D. (Chairman

Activity classification using realistic data from wearable sensors.

PubMed

Pärkkä, Juha; Ermes, Miikka; Korpipää, Panu; Mäntyjärvi, Jani; Peltola, Johannes; Korhonen, Ilkka

2006-01-01

Automatic classification of everyday activities can be used for promotion of health-enhancing physical activities and a healthier lifestyle. In this paper, methods used for classification of everyday activities like walking, running, and cycling are described. The aim of the study was to find out how to recognize activities, which sensors are useful and what kind of signal processing and classification is required. A large and realistic data library of sensor data was collected. Sixteen test persons took part in the data collection, resulting in approximately 31 h of annotated, 35-channel data recorded in an everyday environment. The test persons carried a set of wearable sensors while performing several activities during the 2-h measurement session. Classification results of three classifiers are shown: custom decision tree, automatically generated decision tree, and artificial neural network. The classification accuracies using leave-one-subject-out cross validation range from 58 to 97% for custom decision tree classifier, from 56 to 97% for automatically generated decision tree, and from 22 to 96% for artificial neural network. Total classification accuracy is 82 % for custom decision tree classifier, 86% for automatically generated decision tree, and 82% for artificial neural network.

Bonding techniques for hybrid active pixel sensors (HAPS)

NASA Astrophysics Data System (ADS)

Bigas, M.; Cabruja, E.; Lozano, M.

2007-05-01

A hybrid active pixel sensor (HAPS) consists of an array of sensing elements which is connected to an electronic read-out unit. The most used way to connect these two different devices is bump bonding. This interconnection technique is very suitable for these systems because it allows a very fine pitch and a high number of I/Os. However, there are other interconnection techniques available such as direct bonding. This paper, as a continuation of a review [M. Lozano, E. Cabruja, A. Collado, J. Santander, M. Ullan, Nucl. Instr. and Meth. A 473 (1-2) (2001) 95-101] published in 2001, presents an update of the different advanced bonding techniques available for manufacturing a hybrid active pixel detector.

Integrating soft sensor systems using conductive thread

NASA Astrophysics Data System (ADS)

Teng, Lijun; Jeronimo, Karina; Wei, Tianqi; Nemitz, Markus P.; Lyu, Geng; Stokes, Adam A.

2018-05-01

We are part of a growing community of researchers who are developing a new class of soft machines. By using mechanically soft materials (MPa modulus) we can design systems which overcome the bulk-mechanical mismatches between soft biological systems and hard engineered components. To develop fully integrated soft machines—which include power, communications, and control sub-systems—the research community requires methods for interconnecting between soft and hard electronics. Sensors based upon eutectic gallium alloys in microfluidic channels can be used to measure normal and strain forces, but integrating these sensors into systems of heterogeneous Young’s modulus is difficult due the complexity of finding a material which is electrically conductive, mechanically flexible, and stable over prolonged periods of time. Many existing gallium-based liquid alloy sensors are not mechanically or electrically robust, and have poor stability over time. We present the design and fabrication of a high-resolution pressure-sensor soft system that can transduce normal force into a digital output. In this soft system, which is built on a monolithic silicone substrate, a galinstan-based microfluidic pressure sensor is integrated with a flexible printed circuit board. We used conductive thread as the interconnect and found that this method alleviates problems arising due to the mechanical mismatch between conventional metal wires and soft or liquid materials. Conductive thread is low-cost, it is readily wetted by the liquid metal, it produces little bending moment into the microfluidic channel, and it can be connected directly onto the copper bond-pads of the flexible printed circuit board. We built a bridge-system to provide stable readings from the galinstan pressure sensor. This system gives linear measurement results between 500-3500 Pa of applied pressure. We anticipate that integrated systems of this type will find utility in soft-robotic systems as used for wearable

Remote environmental sensor array system

NASA Astrophysics Data System (ADS)

Hall, Geoffrey G.

This thesis examines the creation of an environmental monitoring system for inhospitable environments. It has been named The Remote Environmental Sensor Array System or RESA System for short. This thesis covers the development of RESA from its inception, to the design and modeling of the hardware and software required to make it functional. Finally, the actual manufacture, and laboratory testing of the finished RESA product is discussed and documented. The RESA System is designed as a cost-effective way to bring sensors and video systems to the underwater environment. It contains as water quality probe with sensors such as dissolved oxygen, pH, temperature, specific conductivity, oxidation-reduction potential and chlorophyll a. In addition, an omni-directional hydrophone is included to detect underwater acoustic signals. It has a colour, high-definition and a low-light, black and white camera system, which it turn are coupled to a laser scaling system. Both high-intensity discharge and halogen lighting system are included to illuminate the video images. The video and laser scaling systems are manoeuvred using pan and tilt units controlled from an underwater computer box. Finally, a sediment profile imager is included to enable profile images of sediment layers to be acquired. A control and manipulation system to control the instruments and move the data across networks is integrated into the underwater system while a power distribution node provides the correct voltages to power the instruments. Laboratory testing was completed to ensure that the different instruments associated with the RESA performed as designed. This included physical testing of the motorized instruments, calibration of the instruments, benchmark performance testing and system failure exercises.

A Tactile Sensor Network System Using a Multiple Sensor Platform with a Dedicated CMOS-LSI for Robot Applications †

PubMed Central

Shao, Chenzhong; Tanaka, Shuji; Nakayama, Takahiro; Hata, Yoshiyuki; Bartley, Travis; Muroyama, Masanori

2017-01-01

Robot tactile sensation can enhance human–robot communication in terms of safety, reliability and accuracy. The final goal of our project is to widely cover a robot body with a large number of tactile sensors, which has significant advantages such as accurate object recognition, high sensitivity and high redundancy. In this study, we developed a multi-sensor system with dedicated Complementary Metal-Oxide-Semiconductor (CMOS) Large-Scale Integration (LSI) circuit chips (referred to as “sensor platform LSI”) as a framework of a serial bus-based tactile sensor network system. The sensor platform LSI supports three types of sensors: an on-chip temperature sensor, off-chip capacitive and resistive tactile sensors, and communicates with a relay node via a bus line. The multi-sensor system was first constructed on a printed circuit board to evaluate basic functions of the sensor platform LSI, such as capacitance-to-digital and resistance-to-digital conversion. Then, two kinds of external sensors, nine sensors in total, were connected to two sensor platform LSIs, and temperature, capacitive and resistive sensing data were acquired simultaneously. Moreover, we fabricated flexible printed circuit cables to demonstrate the multi-sensor system with 15 sensor platform LSIs operating simultaneously, which showed a more realistic implementation in robots. In conclusion, the multi-sensor system with up to 15 sensor platform LSIs on a bus line supporting temperature, capacitive and resistive sensing was successfully demonstrated. PMID:29061954

Electro-active sensor, method for constructing the same; apparatus and circuitry for detection of electro-active species

NASA Technical Reports Server (NTRS)

Buehler, Martin (Inventor)

2009-01-01

An electro-active sensor includes a nonconductive platform with a first electrode set attached with a first side of a nonconductive platform. The first electrode set serves as an electrochemical cell that may be utilized to detect electro-active species in solution. A plurality of electrode sets and a variety of additional electrochemical cells and sensors may be attached with the nonconductive platform. The present invention also includes a method for constructing the aforementioned electro-active sensor. Additionally, an apparatus for detection and observation is disclosed, where the apparatus includes a sealable chamber for insertion of a portion of an electro-active sensor. The apparatus allows for monitoring and detection activities. Allowing for control of attached cells and sensors, a dual-mode circuitry is also disclosed. The dual-mode circuitry includes a switch, allowing the circuitry to be switched from a potentiostat to a galvanostat mode.

A Sensor System for Detection of Hull Surface Defects

PubMed Central

Navarro, Pedro; Iborra, Andrés; Fernández, Carlos; Sánchez, Pedro; Suardíaz, Juan

2010-01-01

This paper presents a sensor system for detecting defects in ship hull surfaces. The sensor was developed to enable a robotic system to perform grit blasting operations on ship hulls. To achieve this, the proposed sensor system captures images with the help of a camera and processes them in real time using a new defect detection method based on thresholding techniques. What makes this method different is its efficiency in the automatic detection of defects from images recorded in variable lighting conditions. The sensor system was tested under real conditions at a Spanish shipyard, with excellent results. PMID:22163590

Anti-sleepiness sensor systems for sober mental condition

NASA Astrophysics Data System (ADS)

Han, Won Heum; Jung, Hyung Sik; Lee, Hyo Gun

2011-05-01

The anti-sleepiness sensor systems have been devised for soldier's sober mental condition. These systems judge whether the soldier is sleepy or not, on one hand by monitoring open or closed eyes, on the other hand by measuring the heart blood beat and rate on the carotid of human's neck. They reasonably adopt one of the following methods such as optical, mechanical, magnetic impedance and piezoelectric sensor and so on. In this paper, the characteristics of those sensors are compared to one another and subsequently the suitable ones are proposed from the viewpoint of measurement and judgment reliability.; as a sensor to directly monitor the soldier's open/closed eyes the IR (Infrared) sensor is recommended, which is equipped on glasses (so called the anti-sleepiness glasses), and as a sensor to measure the heart beat and rate of blood vein, the piezoelectric PMN-PT crystal sensor mounted on a necklace turns out to be the most suitable owing to its high sensitivity (i.e. the anti-sleepiness necklace). These systems and relevant ideas are also applicable to the civilian usage, namely to the student preparing an examination as well as to the car-driver for safety.

Complex Human Activity Recognition Using Smartphone and Wrist-Worn Motion Sensors.

PubMed

Shoaib, Muhammad; Bosch, Stephan; Incel, Ozlem Durmaz; Scholten, Hans; Havinga, Paul J M

2016-03-24

The position of on-body motion sensors plays an important role in human activity recognition. Most often, mobile phone sensors at the trouser pocket or an equivalent position are used for this purpose. However, this position is not suitable for recognizing activities that involve hand gestures, such as smoking, eating, drinking coffee and giving a talk. To recognize such activities, wrist-worn motion sensors are used. However, these two positions are mainly used in isolation. To use richer context information, we evaluate three motion sensors (accelerometer, gyroscope and linear acceleration sensor) at both wrist and pocket positions. Using three classifiers, we show that the combination of these two positions outperforms the wrist position alone, mainly at smaller segmentation windows. Another problem is that less-repetitive activities, such as smoking, eating, giving a talk and drinking coffee, cannot be recognized easily at smaller segmentation windows unlike repetitive activities, like walking, jogging and biking. For this purpose, we evaluate the effect of seven window sizes (2-30 s) on thirteen activities and show how increasing window size affects these various activities in different ways. We also propose various optimizations to further improve the recognition of these activities. For reproducibility, we make our dataset publicly available.

Complex Human Activity Recognition Using Smartphone and Wrist-Worn Motion Sensors

PubMed Central

Shoaib, Muhammad; Bosch, Stephan; Incel, Ozlem Durmaz; Scholten, Hans; Havinga, Paul J. M.

2016-01-01

The position of on-body motion sensors plays an important role in human activity recognition. Most often, mobile phone sensors at the trouser pocket or an equivalent position are used for this purpose. However, this position is not suitable for recognizing activities that involve hand gestures, such as smoking, eating, drinking coffee and giving a talk. To recognize such activities, wrist-worn motion sensors are used. However, these two positions are mainly used in isolation. To use richer context information, we evaluate three motion sensors (accelerometer, gyroscope and linear acceleration sensor) at both wrist and pocket positions. Using three classifiers, we show that the combination of these two positions outperforms the wrist position alone, mainly at smaller segmentation windows. Another problem is that less-repetitive activities, such as smoking, eating, giving a talk and drinking coffee, cannot be recognized easily at smaller segmentation windows unlike repetitive activities, like walking, jogging and biking. For this purpose, we evaluate the effect of seven window sizes (2–30 s) on thirteen activities and show how increasing window size affects these various activities in different ways. We also propose various optimizations to further improve the recognition of these activities. For reproducibility, we make our dataset publicly available. PMID:27023543

Energy storage management system with distributed wireless sensors

DOEpatents

Farmer, Joseph C.; Bandhauer, Todd M.

2015-12-08

An energy storage system having a multiple different types of energy storage and conversion devices. Each device is equipped with one or more sensors and RFID tags to communicate sensor information wirelessly to a central electronic management system, which is used to control the operation of each device. Each device can have multiple RFID tags and sensor types. Several energy storage and conversion devices can be combined.

A practical indoor context-aware surveillance system with multi-Kinect sensors

NASA Astrophysics Data System (ADS)

Jia, Lili; You, Ying; Li, Tiezhu; Zhang, Shun

2014-11-01

In this paper we develop a novel practical application, which give scalable services to the end users when abnormal actives are happening. Architecture of the application has been presented consisting of network infrared cameras and a communication module. In this intelligent surveillance system we use Kinect sensors as the input cameras. Kinect is an infrared laser camera which its user can access the raw infrared sensor stream. We install several Kinect sensors in one room to track the human skeletons. Each sensor returns the body positions with 15 coordinates in its own coordinate system. We use calibration algorithms to calibrate all the body positions points into one unified coordinate system. With the body positions points, we can infer the surveillance context. Furthermore, the messages from the metadata index matrix will be sent to mobile phone through communication module. User will instantly be aware of an abnormal case happened in the room without having to check the website. In conclusion, theoretical analysis and experimental results in this paper show that the proposed system is reasonable and efficient. And the application method introduced in this paper is not only to discourage the criminals and assist police in the apprehension of suspects, but also can enabled the end-users monitor the indoor environments anywhere and anytime by their phones.

Wireless network system based multi-non-invasive sensors for smart home

NASA Astrophysics Data System (ADS)

Issa Ahmed, Rudhwan

There are several techniques that have been implemented for smart homes usage; however, most of these techniques are limited to a few sensors. Many of these methods neither meet the needs of the user nor are cost-effective. This thesis discusses the design, development, and implementation of a wireless network system, based on multi-non-invasive sensors for smart home environments. This system has the potential to be used as a means to accurately, and remotely, determine the activities of daily living by continuously monitoring relatively simple parameters that measure the interaction between users and their surrounding environment. We designed and developed a prototype system to meet the specific needs of the elderly population. Unlike audio-video based health monitoring systems (which have associated problems such as the encroachment of privacy), the developed system's distinct features ensure privacy and are almost invisible to the occupants, thus increasing the acceptance levels of this system in household environments. The developed system not only achieved high levels of accuracy, but it is also portable, easy to use, cost-effective, and requires low data rates and less power compared to other wireless devices such as Wi-Fi, Bluetooth, wireless USB, Ultra wideband (UWB), or Infrared (IR) wireless. Field testing of the prototype system was conducted at different locations inside and outside of the Minto Building (Centre for Advanced Studies in Engineering at Carleton University) as well as other locations, such as the washroom, kitchen, and living room of a prototype apartment. The main goal of the testing was to determine the range of the prototype system and the functionality of each sensor in different environments. After it was verified that the system operated well in all of the tested environments, data were then collected at the different locations for analysis and interpretation in order to identify the activities of daily living of an occupant.

Toward sensor-based context aware systems.

PubMed

Sakurai, Yoshitaka; Takada, Kouhei; Anisetti, Marco; Bellandi, Valerio; Ceravolo, Paolo; Damiani, Ernesto; Tsuruta, Setsuo

2012-01-01

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

Improving activity recognition using a wearable barometric pressure sensor in mobility-impaired stroke patients.

PubMed

Massé, Fabien; Gonzenbach, Roman R; Arami, Arash; Paraschiv-Ionescu, Anisoara; Luft, Andreas R; Aminian, Kamiar

2015-08-25

Stroke survivors often suffer from mobility deficits. Current clinical evaluation methods, including questionnaires and motor function tests, cannot provide an objective measure of the patients' mobility in daily life. Physical activity performance in daily-life can be assessed using unobtrusive monitoring, for example with a single sensor module fixed on the trunk. Existing approaches based on inertial sensors have limited performance, particularly in detecting transitions between different activities and postures, due to the inherent inter-patient variability of kinematic patterns. To overcome these limitations, one possibility is to use additional information from a barometric pressure (BP) sensor. Our study aims at integrating BP and inertial sensor data into an activity classifier in order to improve the activity (sitting, standing, walking, lying) recognition and the corresponding body elevation (during climbing stairs or when taking an elevator). Taking into account the trunk elevation changes during postural transitions (sit-to-stand, stand-to-sit), we devised an event-driven activity classifier based on fuzzy-logic. Data were acquired from 12 stroke patients with impaired mobility, using a trunk-worn inertial and BP sensor. Events, including walking and lying periods and potential postural transitions, were first extracted. These events were then fed into a double-stage hierarchical Fuzzy Inference System (H-FIS). The first stage processed the events to infer activities and the second stage improved activity recognition by applying behavioral constraints. Finally, the body elevation was estimated using a pattern-enhancing algorithm applied on BP. The patients were videotaped for reference. The performance of the algorithm was estimated using the Correct Classification Rate (CCR) and F-score. The BP-based classification approach was benchmarked against a previously-published fuzzy-logic classifier (FIS-IMU) and a conventional epoch-based classifier (EPOCH

Towards Autonomous Inspection of Space Systems Using Mobile Robotic Sensor Platforms

NASA Technical Reports Server (NTRS)

Wong, Edmond; Saad, Ashraf; Litt, Jonathan S.

2007-01-01

The space transportation systems required to support NASA's Exploration Initiative will demand a high degree of reliability to ensure mission success. This reliability can be realized through autonomous fault/damage detection and repair capabilities. It is crucial that such capabilities are incorporated into these systems since it will be impractical to rely upon Extra-Vehicular Activity (EVA), visual inspection or tele-operation due to the costly, labor-intensive and time-consuming nature of these methods. One approach to achieving this capability is through the use of an autonomous inspection system comprised of miniature mobile sensor platforms that will cooperatively perform high confidence inspection of space vehicles and habitats. This paper will discuss the efforts to develop a small scale demonstration test-bed to investigate the feasibility of using autonomous mobile sensor platforms to perform inspection operations. Progress will be discussed in technology areas including: the hardware implementation and demonstration of robotic sensor platforms, the implementation of a hardware test-bed facility, and the investigation of collaborative control algorithms.

Validation of mercury tip-switch and accelerometer activity sensors for identifying resting and active behavior in bears

USGS Publications Warehouse

Jasmine Ware,; Rode, Karyn D.; Pagano, Anthony M.; Bromaghin, Jeffrey F.; Robbins, Charles T.; Joy Erlenbach,; Shannon Jensen,; Amy Cutting,; Nicole Nicassio-Hiskey,; Amy Hash,; Owen, Megan A.; Heiko Jansen,

2015-01-01

Activity sensors are often included in wildlife transmitters and can provide information on the behavior and activity patterns of animals remotely. However, interpreting activity-sensor data relative to animal behavior can be difficult if animals cannot be continuously observed. In this study, we examined the performance of a mercury tip-switch and a tri-axial accelerometer housed in collars to determine whether sensor data can be accurately classified as resting and active behaviors and whether data are comparable for the 2 sensor types. Five captive bears (3 polar [Ursus maritimus] and 2 brown [U. arctos horribilis]) were fitted with a collar specially designed to internally house the sensors. The bears’ behaviors were recorded, classified, and then compared with sensor readings. A separate tri-axial accelerometer that sampled continuously at a higher frequency and provided raw acceleration values from 3 axes was also mounted on the collar to compare with the lower resolution sensors. Both accelerometers more accurately identified resting and active behaviors at time intervals ranging from 1 minute to 1 hour (≥91.1% accuracy) compared with the mercury tip-switch (range = 75.5–86.3%). However, mercury tip-switch accuracy improved when sampled at longer intervals (e.g., 30–60 min). Data from the lower resolution accelerometer, but not the mercury tip-switch, accurately predicted the percentage of time spent resting during an hour. Although the number of bears available for this study was small, our results suggest that these activity sensors can remotely identify resting versus active behaviors across most time intervals. We recommend that investigators consider both study objectives and the variation in accuracy of classifying resting and active behaviors reported here when determining sampling interval.

Active control for vibration suppression in a flexible beam using a modal domain optical fiber sensor

NASA Technical Reports Server (NTRS)

Cox, D. E.; Lindner, D. K.

1991-01-01

An account is given of the use of a modal-domain (MD) fiber-optic sensor as an active control system component for vibration suppression, whose output is proportional to the integral of the axial strain along the optical fiber. When an MD sensor is attached to, or embedded in, a flexible structure, it senses the strain in the structure along its gage length. On the basis of the present integration of the sensor model into a flexible-structure model, it becomes possible to design a control system with a dynamic compensator which adds damping to the low-order modes of the flexible structure. This modeling procedure has been experimentally validated.

A Fault Tolerant System for an Integrated Avionics Sensor Configuration

NASA Technical Reports Server (NTRS)

Caglayan, A. K.; Lancraft, R. E.

1984-01-01

An aircraft sensor fault tolerant system methodology for the Transport Systems Research Vehicle in a Microwave Landing System (MLS) environment is described. The fault tolerant system provides reliable estimates in the presence of possible failures both in ground-based navigation aids, and in on-board flight control and inertial sensors. Sensor failures are identified by utilizing the analytic relationships between the various sensors arising from the aircraft point mass equations of motion. The estimation and failure detection performance of the software implementation (called FINDS) of the developed system was analyzed on a nonlinear digital simulation of the research aircraft. Simulation results showing the detection performance of FINDS, using a dual redundant sensor compliment, are presented for bias, hardover, null, ramp, increased noise and scale factor failures. In general, the results show that FINDS can distinguish between normal operating sensor errors and failures while providing an excellent detection speed for bias failures in the MLS, indicated airspeed, attitude and radar altimeter sensors.

Reconfigurable Sensor Monitoring System

NASA Technical Reports Server (NTRS)

Alhorn, Dean C. (Inventor); Dutton, Kenneth R. (Inventor); Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

2017-01-01

A reconfigurable sensor monitoring system includes software tunable filters, each of which is programmable to condition one type of analog signal. A processor coupled to the software tunable filters receives each type of analog signal so-conditioned.

Active Wireless System for Structural Health Monitoring Applications.

PubMed

Perera, Ricardo; Pérez, Alberto; García-Diéguez, Marta; Zapico-Valle, José Luis

2017-12-11

The use of wireless sensors in Structural Health Monitoring (SHM) has increased significantly in the last years. Piezoelectric-based lead zirconium titanate (PZT) sensors have been on the rise in SHM due to their superior sensing abilities. They are applicable in different technologies such as electromechanical impedance (EMI)-based SHM. This work develops a flexible wireless smart sensor (WSS) framework based on the EMI method using active sensors for full-scale and autonomous SHM. In contrast to passive sensors, the self-sensing properties of the PZTs allow interrogating with or exciting a structure when desired. The system integrates the necessary software and hardware within a service-oriented architecture approach able to provide in a modular way the services suitable to satisfy the key requirements of a WSS. The framework developed in this work has been validated on different experimental applications. Initially, the reliability of the EMI method when carried out with the proposed wireless sensor system is evaluated by comparison with the wireless counterpart. Afterwards, the performance of the system is evaluated in terms of software stability and reliability of functioning.

Transparent Fingerprint Sensor System for Large Flat Panel Display.

PubMed

Seo, Wonkuk; Pi, Jae-Eun; Cho, Sung Haeung; Kang, Seung-Youl; Ahn, Seong-Deok; Hwang, Chi-Sun; Jeon, Ho-Sik; Kim, Jong-Uk; Lee, Myunghee

2018-01-19

In this paper, we introduce a transparent fingerprint sensing system using a thin film transistor (TFT) sensor panel, based on a self-capacitive sensing scheme. An armorphousindium gallium zinc oxide (a-IGZO) TFT sensor array and associated custom Read-Out IC (ROIC) are implemented for the system. The sensor panel has a 200 × 200 pixel array and each pixel size is as small as 50 μm × 50 μm. The ROIC uses only eight analog front-end (AFE) amplifier stages along with a successive approximation analog-to-digital converter (SAR ADC). To get the fingerprint image data from the sensor array, the ROIC senses a capacitance, which is formed by a cover glass material between a human finger and an electrode of each pixel of the sensor array. Three methods are reviewed for estimating the self-capacitance. The measurement result demonstrates that the transparent fingerprint sensor system has an ability to differentiate a human finger's ridges and valleys through the fingerprint sensor array.

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

PubMed

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

2014-01-01

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

Spectrum-modulating fiber-optic sensors for aircraft control systems

NASA Technical Reports Server (NTRS)

Beheim, Glenn; Fritsch, Klaus

1987-01-01

A family of fiber-optic sensors for aircraft engine control systems is described. Each of these sensors uses a spectrum-modulation method to obtain an output which is largely independent of the fiber link transmissivity. A position encoder is described which uses a code plate to digitally modulate the sensor output spectrum. Also described are pressure and temperature sensors, each of which uses a Fabry-Perot cavity to modulate the sensor output spectrum as a continuous function of the measurand. A technique is described whereby a collection of these sensors may be effectively combined to perform a number of the measurements which are required by an aircraft-engine control system.

Third-generation imaging sensor system concepts

NASA Astrophysics Data System (ADS)

Reago, Donald A.; Horn, Stuart B.; Campbell, James, Jr.; Vollmerhausen, Richard H.

1999-07-01

Second generation forward looking infrared sensors, based on either parallel scanning, long wave (8 - 12 um) time delay and integration HgCdTe detectors or mid wave (3 - 5 um), medium format staring (640 X 480 pixels) InSb detectors, are being fielded. The science and technology community is now turning its attention toward the definition of a future third generation of FLIR sensors, based on emerging research and development efforts. Modeled third generation sensor performance demonstrates a significant improvement in performance over second generation, resulting in enhanced lethality and survivability on the future battlefield. In this paper we present the current thinking on what third generation sensors systems will be and the resulting requirements for third generation focal plane array detectors. Three classes of sensors have been identified. The high performance sensor will contain a megapixel or larger array with at least two colors. Higher operating temperatures will also be the goal here so that power and weight can be reduced. A high performance uncooled sensor is also envisioned that will perform somewhere between first and second generation cooled detectors, but at significantly lower cost, weight, and power. The final third generation sensor is a very low cost micro sensor. This sensor can open up a whole new IR market because of its small size, weight, and cost. Future unattended throwaway sensors, micro UAVs, and helmet mounted IR cameras will be the result of this new class.

Force Sensing Resistor (FSR): a brief overview and the low-cost sensor for active compliance control

NASA Astrophysics Data System (ADS)

Sadun, A. S.; Jalani, J.; Sukor, J. A.

2016-07-01

Force Sensing Resistors (FSR) sensors are devices that allow measuring static and dynamic forces applied to a contact surface. Their range of responses is basically depending on the variation of its electric resistance. In general, Flexiforce and Interlink are two common types of FSR sensors that are available, cheap and easily found in the market. Studies have shown that the FSR sensors are usually applied for robotic grippers and for biomechanical fields. This paper provides a brief overview of the application of the FSR sensors. Subsequently, two different set of experiments are carried out to test the effectiveness of the Flexiforce and Interlink sensors. First, the hardness detector system (Case Study A) and second, the force-position control system (Case Study B). The hardware used for the experiment was developed from low-cost materials. The results revealed that both FSR sensors are sufficient and reliable to provide a good sensing modality particularly for measuring force. Apart from the low-cost sensors, essentially, the FSR sensors are very useful devices that able to provide a good active compliance control, particularly for the grasping robotic hand.

Nanowire humidity optical sensor system based on fast Fourier transform technique

NASA Astrophysics Data System (ADS)

Rota-Rodrigo, S.; Pérez-Herrera, R.; Lopez-Aldaba, A.; López Bautista, M. C.; Esteban, O.; López-Amo, M.

2015-09-01

In this paper, a new sensor system for relative humidity measurements based on its interaction with the evanescent field of a nanowire is presented. The interrogation of the sensing head is carried out by monitoring the fast Fourier transform phase variations of one of the nanowire interference frequencies. This method is independent of the signal amplitude and also avoids the necessity of tracking the wavelength evolution in the spectrum, which can be a handicap when there are multiple interference frequency components with different sensitivities. The sensor is operated within a wide humidity range (20%-70% relative humidity) with a maximum sensitivity achieved of 0.14rad/% relative humidity. Finally, due to the system uses an optical interrogator as unique active element, the system presents a cost-effective feature.

Optical detection system for MEMS-type pressure sensor

NASA Astrophysics Data System (ADS)

Sareło, K.; Górecka-Drzazga, A.; Dziuban, J. A.

2015-07-01

In this paper a special optical detection system designed for a MEMS-type (micro-electro-mechanical system) silicon pressure sensor is presented. The main part of the optical system—a detection unit with a perforated membrane—is bonded to the silicon sensor, and placed in a measuring system. An external light source illuminates the membrane of the pressure sensor. Owing to the light reflected from the deflected membrane sensor, the optical pattern consisting of light points is visible, and pressure can be estimated. The optical detection unit (20   ×   20   ×   20.4 mm3) is fabricated using microengineering techniques. Its dimensions are adjusted to the dimensions of the pressure sensor (5   ×   5 mm2 silicon membrane). Preliminary tests of the optical detection unit integrated with the silicon pressure sensor are carried out. For the membrane sensor from 15 to 60 µm thick, a repeatable detection of the differential pressure in the range of 0 to 280 kPa is achieved. The presented optical microsystem is especially suitable for the pressure measurements in a high radiation environment.

Smart spectroscopy sensors: II. Narrow-band laser systems

NASA Astrophysics Data System (ADS)

Matharoo, Inderdeep; Peshko, Igor

2013-03-01

This paper describes the principles of operation of a miniature multifunctional optical sensory system based on laser technology and spectroscopic principles of analysis. The operation of the system as a remote oxygen sensor has been demonstrated. The multi-component alarm sensor has been designed to recognise gases and to measure gas concentration (O2, CO2, CO, CH4, N2O, C2H2, HI, OH radicals and H2O vapour, including semi-heavy water), temperature, pressure, humidity, and background radiation from the environment. Besides gas sensing, the same diode lasers are used for range-finding and to provide sensor self-calibration. The complete system operates as an inhomogeneous sensory network: the laser sensors are capable of using information received from environmental sensors for improving accuracy and reliability of gas concentration measurement. The sources of measurement errors associated with hardware and algorithms of operation and data processing have been analysed in detail.

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

Alkali metals in addition to acidic pH activate the EvgS histidine kinase sensor in Escherichia coli.

PubMed

Eguchi, Yoko; Utsumi, Ryutaro

2014-09-01

Two-component signal transduction systems (TCSs) in bacteria perceive environmental stress and transmit the information via phosphorelay to adjust multiple cellular functions for adaptation. The EvgS/EvgA system is a TCS that confers acid resistance to Escherichia coli cells. Activation of the EvgS sensor initiates a cascade of transcription factors, EvgA, YdeO, and GadE, which induce the expression of a large group of acid resistance genes. We searched for signals activating EvgS and found that a high concentration of alkali metals (Na(+), K(+)) in addition to low pH was essential for the activation. EvgS is a histidine kinase, with a large periplasmic sensor region consisting of two tandem PBPb (bacterial periplasmic solute-binding protein) domains at its N terminus. The periplasmic sensor region of EvgS was necessary for EvgS activation, and Leu152, located within the first PBPb domain, was involved in the activation. Furthermore, chimeras of EvgS and PhoQ histidine kinases suggested that alkali metals were perceived at the periplasmic sensor region, whereas the cytoplasmic linker domain, connecting the transmembrane region and the histidine kinase domain, was required for low-pH perception. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

A wearable sensor for unobtrusive, long-term assessment of electrodermal activity.

PubMed

Poh, Ming-Zher; Swenson, Nicholas C; Picard, Rosalind W

2010-05-01

Electrodermal activity (EDA) is a sensitive index of sympathetic nervous system activity. Due to the lack of sensors that can be worn comfortably during normal daily activity and over extensive periods of time, research in this area is limited to laboratory settings or artificial clinical environments. We developed a novel, unobtrusive, nonstigmatizing, wrist-worn integrated sensor, and present, for the very first time, a demonstration of long-term, continuous assessment of EDA outside of a laboratory setting. We evaluated the performance of our device against a Food and Drug Administration (FDA) approved system for the measurement of EDA during physical, cognitive, as well as emotional stressors at both palmar and distal forearm sites, and found high correlations across all the tests. We also evaluated the choice of electrode material by comparing conductive fabric with Ag/AgCl electrodes and discuss the limitations found. An important result presented in this paper is evidence that the distal forearm is a viable alternative to the traditional palmar sites for EDA measurements. Our device offers the unprecedented ability to perform comfortable, long-term, and in situ assessment of EDA. This paper opens up opportunities for future investigations that were previously not feasible, and could have far-reaching implications for diagnosis and understanding of psychological or neurological conditions.

Implementation of Sensor and Control Designs for Bioregenerative Systems

NASA Technical Reports Server (NTRS)

Rodriguez, Pedro R. (Editor)

1990-01-01

The goal of the Spring 1990 EGM 4001 Design class was to design, fabricate, and test sensors and control systems for a closed loop life support system (CLLSS). The designs investigated were to contribute to the development of NASA's Controlled Ecological Life Support System (CELSS) at Kennedy Space Center (KSC). Designs included a seed moisture content sensor, a porous medium wetness sensor, a plant health sensor, and a neural network control system. The seed group focused on the design and implementation of a sensor that could detect the moisture content of a seed batch. The porous medium wetness group concentrated on the development of a sensor to monitor the amount of nutrient solution within a porous plate incorporating either infrared reflectance or thermal conductance properties. The plant health group examined the possibility of remotely monitoring the health of the plants within the Biomass Production Chamber (BPC) using infrared reflectance properties. Finally, the neural network group concentrated on the ability to use parallel processing in order to control a robot arm and analyze the data from the health sensor to detect regions of a plant.

Recognition of military-specific physical activities with body-fixed sensors.

PubMed

Wyss, Thomas; Mäder, Urs

2010-11-01

The purpose of this study was to develop and validate an algorithm for recognizing military-specific, physically demanding activities using body-fixed sensors. To develop the algorithm, the first group of study participants (n = 15) wore body-fixed sensors capable of measuring acceleration, step frequency, and heart rate while completing six military-specific activities: walking, marching with backpack, lifting and lowering loads, lifting and carrying loads, digging, and running. The accuracy of the algorithm was tested in these isolated activities in a laboratory setting (n = 18) and in the context of daily military training routine (n = 24). The overall recognition rates during isolated activities and during daily military routine activities were 87.5% and 85.5%, respectively. We conclude that the algorithm adequately recognized six military-specific physical activities based on sensor data alone both in a laboratory setting and in the military training environment. By recognizing type of physical activities this objective method provides additional information on military-job descriptions.

A Decision Support System for Evaluating Systems of Undersea Sensors and Weapons

DTIC Science & Technology

2015-12-01

distribution is unlimited A DECISION SUPPORT SYSTEM FOR EVALUATING SYSTEMS OF UNDERSEA SENSORS AND WEAPONS by Team Mental Focus Cohort 142O...A DECISION SUPPORT SYSTEM FOR EVALUATING SYSTEMS OF UNDERSEA SENSORS AND WEAPONS 5. FUNDING NUMBERS 6. AUTHOR(S) Systems Engineering Cohort...undersea weapons, it requires the supporting tools to evaluate and predict the effectiveness of these system concepts. While current naval minefield

Commercial Applications Multispectral Sensor System

NASA Technical Reports Server (NTRS)

Birk, Ronald J.; Spiering, Bruce

1993-01-01

NASA's Office of Commercial Programs is funding a multispectral sensor system to be used in the development of remote sensing applications. The Airborne Terrestrial Applications Sensor (ATLAS) is designed to provide versatility in acquiring spectral and spatial information. The ATLAS system will be a test bed for the development of specifications for airborne and spaceborne remote sensing instrumentation for dedicated applications. This objective requires spectral coverage from the visible through thermal infrared wavelengths, variable spatial resolution from 2-25 meters; high geometric and geo-location accuracy; on-board radiometric calibration; digital recording; and optimized performance for minimized cost, size, and weight. ATLAS is scheduled to be available in 3rd quarter 1992 for acquisition of data for applications such as environmental monitoring, facilities management, geographic information systems data base development, and mineral exploration.

Real-Time Sensor Validation System Developed for Reusable Launch Vehicle Testbed

NASA Technical Reports Server (NTRS)

Jankovsky, Amy L.

1997-01-01

A real-time system for validating sensor health has been developed for the reusable launch vehicle (RLV) program. This system, which is part of the propulsion checkout and control system (PCCS), was designed for use in an integrated propulsion technology demonstrator testbed built by Rockwell International and located at the NASA Marshall Space Flight Center. Work on the sensor health validation system, a result of an industry-NASA partnership, was completed at the NASA Lewis Research Center, then delivered to Marshall for integration and testing. The sensor validation software performs three basic functions: it identifies failed sensors, it provides reconstructed signals for failed sensors, and it identifies off-nominal system transient behavior that cannot be attributed to a failed sensor. The code is initiated by host software before the start of a propulsion system test, and it is called by the host program every control cycle. The output is posted to global memory for use by other PCCS modules. Output includes a list indicating the status of each sensor (i.e., failed, healthy, or reconstructed) and a list of features that are not due to a sensor failure. If a sensor failure is found, the system modifies that sensor's data array by substituting a reconstructed signal, when possible, for use by other PCCS modules.

Battery system with temperature sensors

DOEpatents

Wood, Steven J.; Trester, Dale B.

2012-11-13

A battery system to monitor temperature includes at least one cell with a temperature sensing device proximate the at least one cell. The battery system also includes a flexible member that holds the temperature sensor proximate to the at least one cell.

Fiber Bragg grating strain sensors to monitor and study active volcanoes

NASA Astrophysics Data System (ADS)

Sorrentino, Fiodor; Beverini, Nicolò; Carbone, Daniele; Carelli, Giorgio; Francesconi, Francesco; Gambino, Salvo; Giacomelli, Umberto; Grassi, Renzo; Maccioni, Enrico; Morganti, Mauro

2016-04-01

Stress and strain changes are among the best indicators of impending volcanic activity. In volcano geodesy, borehole volumetric strain-meters are mostly utilized. However, they are not easy to install and involve high implementation costs. Advancements in opto-electronics have allowed the development of low-cost sensors, reliable, rugged and compact, thus particularly suitable for field application. In the framework of the EC FP7 MED-SUV project, we have developed strain sensors based on the fiber Bragg grating (FBG) technology. In comparison with previous implementation of the FBG technology to study rock deformations, we have designed a system that is expected to offer a significantly higher resolution and accuracy in static measurements and a smooth dynamic response up to 100 Hz, implying the possibility to observe seismic waves. The system performances are tailored to suit the requirements of volcano monitoring, with special attention to power consumption and to the trade-off between performance and cost. Preliminary field campaigns were carried out on Mt. Etna (Italy) using a prototypal single-axis FBG strain sensor, to check the system performances in out-of-the-lab conditions and in the harsh volcanic environment (lack of mains electricity for power, strong diurnal temperature changes, strong wind, erosive ash, snow and ice during the winter time). We also designed and built a FBG strain sensor featuring a multi-axial configuration which was tested and calibrated in the laboratory. This instrument is suitable for borehole installation and will be tested on Etna soon.

Sensor Selection and Chemo-Sensory Optimization: Toward an Adaptable Chemo-Sensory System

PubMed Central

Vergara, Alexander; Llobet, Eduard

2011-01-01

Over the past two decades, despite the tremendous research on chemical sensors and machine olfaction to develop micro-sensory systems that will accomplish the growing existent needs in personal health (implantable sensors), environment monitoring (widely distributed sensor networks), and security/threat detection (chemo/bio warfare agents), simple, low-cost molecular sensing platforms capable of long-term autonomous operation remain beyond the current state-of-the-art of chemical sensing. A fundamental issue within this context is that most of the chemical sensors depend on interactions between the targeted species and the surfaces functionalized with receptors that bind the target species selectively, and that these binding events are coupled with transduction processes that begin to change when they are exposed to the messy world of real samples. With the advent of fundamental breakthroughs at the intersection of materials science, micro- and nano-technology, and signal processing, hybrid chemo-sensory systems have incorporated tunable, optimizable operating parameters, through which changes in the response characteristics can be modeled and compensated as the environmental conditions or application needs change. The objective of this article, in this context, is to bring together the key advances at the device, data processing, and system levels that enable chemo-sensory systems to “adapt” in response to their environments. Accordingly, in this review we will feature the research effort made by selected experts on chemical sensing and information theory, whose work has been devoted to develop strategies that provide tunability and adaptability to single sensor devices or sensory array systems. Particularly, we consider sensor-array selection, modulation of internal sensing parameters, and active sensing. The article ends with some conclusions drawn from the results presented and a visionary look toward the future in terms of how the field may evolve. PMID

Sensor selection and chemo-sensory optimization: toward an adaptable chemo-sensory system.

PubMed

Vergara, Alexander; Llobet, Eduard

2011-01-01

Over the past two decades, despite the tremendous research on chemical sensors and machine olfaction to develop micro-sensory systems that will accomplish the growing existent needs in personal health (implantable sensors), environment monitoring (widely distributed sensor networks), and security/threat detection (chemo/bio warfare agents), simple, low-cost molecular sensing platforms capable of long-term autonomous operation remain beyond the current state-of-the-art of chemical sensing. A fundamental issue within this context is that most of the chemical sensors depend on interactions between the targeted species and the surfaces functionalized with receptors that bind the target species selectively, and that these binding events are coupled with transduction processes that begin to change when they are exposed to the messy world of real samples. With the advent of fundamental breakthroughs at the intersection of materials science, micro- and nano-technology, and signal processing, hybrid chemo-sensory systems have incorporated tunable, optimizable operating parameters, through which changes in the response characteristics can be modeled and compensated as the environmental conditions or application needs change. The objective of this article, in this context, is to bring together the key advances at the device, data processing, and system levels that enable chemo-sensory systems to "adapt" in response to their environments. Accordingly, in this review we will feature the research effort made by selected experts on chemical sensing and information theory, whose work has been devoted to develop strategies that provide tunability and adaptability to single sensor devices or sensory array systems. Particularly, we consider sensor-array selection, modulation of internal sensing parameters, and active sensing. The article ends with some conclusions drawn from the results presented and a visionary look toward the future in terms of how the field may evolve.

CMOS-MEMS Chemiresistive and Chemicapacitive Chemical Sensor System

NASA Astrophysics Data System (ADS)

Lazarus, Nathan S.

Integrating chemical sensors with testing electronics is a powerful technique with the potential to lower power and cost and allow for lower system limits of detection. This thesis explores the possibility of creating an integrated sensor system intended to be embedded within respirator cartridges to notify the user that hazardous chemicals will soon leak into the face mask. For a chemical sensor designer, this application is particularly challenging due to the need for a very sensitive and cheap sensor that will be exposed to widely varying environmental conditions during use. An octanethiol-coated gold nanoparticle chemiresistor to detect industrial solvents is developed, focusing on characterizing the environmental stability and limits of detection of the sensor. Since the chemiresistor was found to be highly sensitive to water vapor, a series of highly sensitive humidity sensor topologies were developed, with sensitivities several times previous integrated capacitive humidity sensors achieved. Circuit techniques were then explored to reduce the humidity sensor limits of detection, including the analysis of noise, charge injection, jitter and clock feedthrough in a charge-based capacitance measurement (CBCM) circuit and the design of a low noise Colpitts LC oscillator. The characterization of high resistance gold nanoclusters for capacitive chemical sensing was also performed. In the final section, a preconcentrator, a heater element intended to release a brief concentrated pulse of analate, was developed and tested for the purposes of lowering the system limit of detection.

Motion and ranging sensor system for through-the-wall surveillance system

NASA Astrophysics Data System (ADS)

Black, Jeffrey D.

2002-08-01

A portable Through-the-Wall Surveillance System is being developed for law enforcement, counter-terrorism, and military use. The Motion and Ranging Sensor is a radar that operates in a frequency band that allows for surveillance penetration of most non-metallic walls. Changes in the sensed radar returns are analyzed to detect the human motion that would typically be present during a hostage or barricaded suspect scenario. The system consists of a Sensor Unit, a handheld Remote Display Unit, and an optional laptop computer Command Display Console. All units are battery powered and a wireless link provides command and data communication between units. The Sensor Unit is deployed close to the wall or door through which the surveillance is to occur. After deploying the sensor the operator may move freely as required by the scenario. Up to five Sensor Units may be deployed at a single location. A software upgrade to the Command Display Console is also being developed. This software upgrade will combine the motion detected by multiple Sensor Units and determine and track the location of detected motion in two dimensions.

Multidimensional System Analysis of Electro-Optic Sensors with Sampled Deterministic Output.

DTIC Science & Technology

1987-12-18

System descriptions of scanning and staring electro - optic sensors with sampled output are developed as follows. Functions representing image...to complete the system descriptions. The results should be useful for designing electro - optic sensor systems and correcting data for instrumental...effects and other experimental conditions. Keywords include: Electro - optic system analysis, Scanning sensors, Staring sensors, Spatial sampling, and Temporal sampling.

An evaluation of three-dimensional sensors for the extravehicular activity helper/retreiver

NASA Technical Reports Server (NTRS)

Magee, Michael

1993-01-01

The Extravehicular Activity Retriever/Helper (EVAHR) is a robotic device currently under development at the NASA Johnson Space Center that is designed to fetch objects or to assist in retrieving an astronaut who may have become inadvertently de-tethered. The EVAHR will be required to exhibit a high degree of intelligent autonomous operation and will base much of its reasoning upon information obtained from one or more three-dimensional sensors that it will carry and control. At the highest level of visual cognition and reasoning, the EVAHR will be required to detect objects, recognize them, and estimate their spatial orientation and location. The recognition phase and estimation of spatial pose will depend on the ability of the vision system to reliably extract geometric features of the objects such as whether the surface topologies observed are planar or curved and the spatial relationships between the component surfaces. In order to achieve these tasks, accurate sensing of the operational environment and objects in the environment will therefore be critical. The qualitative and quantitative results of empirical studies of three sensors that are capable of providing three-dimensional information to the EVAHR, but using completely different hardware approaches are documented. The first of these devices is a phase shift laser with an effective operating range (ambiguity interval) of approximately 15 meters. The second sensor is a laser triangulation system designed to operate at much closer range and to provide higher resolution images. The third sensor is a dual camera stereo imaging system from which range images can also be obtained. The remainder of the report characterizes the strengths and weaknesses of each of these systems relative to quality of data extracted and how different object characteristics affect sensor operation.

Transparent Fingerprint Sensor System for Large Flat Panel Display

PubMed Central

Seo, Wonkuk; Pi, Jae-Eun; Cho, Sung Haeung; Kang, Seung-Youl; Ahn, Seong-Deok; Hwang, Chi-Sun; Jeon, Ho-Sik; Kim, Jong-Uk

2018-01-01

In this paper, we introduce a transparent fingerprint sensing system using a thin film transistor (TFT) sensor panel, based on a self-capacitive sensing scheme. An armorphousindium gallium zinc oxide (a-IGZO) TFT sensor array and associated custom Read-Out IC (ROIC) are implemented for the system. The sensor panel has a 200 × 200 pixel array and each pixel size is as small as 50 μm × 50 μm. The ROIC uses only eight analog front-end (AFE) amplifier stages along with a successive approximation analog-to-digital converter (SAR ADC). To get the fingerprint image data from the sensor array, the ROIC senses a capacitance, which is formed by a cover glass material between a human finger and an electrode of each pixel of the sensor array. Three methods are reviewed for estimating the self-capacitance. The measurement result demonstrates that the transparent fingerprint sensor system has an ability to differentiate a human finger’s ridges and valleys through the fingerprint sensor array. PMID:29351218

Functionalized active-nucleus complex sensor

DOEpatents

Pines, Alexander; Wemmer, David E.; Spence, Megan; Rubin, Seth

2003-11-25

A functionalized active-nucleus complex sensor that selectively associates with one or more target species, and a method for assaying and screening for one or a plurality of target species utilizing one or a plurality of functionalized active-nucleus complexes with at least two of the functionalized active-nucleus complexes having an attraction affinity to different corresponding target species. The functionalized active-nucleus complex has an active-nucleus and a targeting carrier. The method involves functionalizing an active-nucleus, for each functionalized active-nucleus complex, by incorporating the active-nucleus into a macromolucular or molecular complex that is capable of binding one of the target species and then bringing the macromolecular or molecular complexes into contact with the target species and detecting the occurrence of or change in a nuclear magnetic resonance signal from each of the active-nuclei in each of the functionalized active-nucleus complexes.

SVM-based multi-sensor fusion for free-living physical activity assessment.

PubMed

Liu, Shaopeng; Gao, Robert X; John, Dinesh; Staudenmayer, John; Freedson, Patty S

2011-01-01

This paper presents a sensor fusion method for assessing physical activity (PA) of human subjects, based on the support vector machines (SVMs). Specifically, acceleration and ventilation measured by a wearable multi-sensor device on 50 test subjects performing 13 types of activities of varying intensities are analyzed, from which the activity types and related energy expenditures are derived. The result shows that the method correctly recognized the 13 activity types 84.7% of the time, which is 26% higher than using a hip accelerometer alone. Also, the method predicted the associated energy expenditure with a root mean square error of 0.43 METs, 43% lower than using a hip accelerometer alone. Furthermore, the fusion method was effective in reducing the subject-to-subject variability (standard deviation of recognition accuracies across subjects) in activity recognition, especially when data from the ventilation sensor was added to the fusion model. These results demonstrate that the multi-sensor fusion technique presented is more effective in assessing activities of varying intensities than the traditional accelerometer-alone based methods.

CardioGuard: A Brassiere-Based Reliable ECG Monitoring Sensor System for Supporting Daily Smartphone Healthcare Applications

PubMed Central

Kwon, Sungjun; Kim, Jeehoon; Kang, Seungwoo; Lee, Youngki; Baek, Hyunjae

2014-01-01

Abstract We propose CardioGuard, a brassiere-based reliable electrocardiogram (ECG) monitoring sensor system, for supporting daily smartphone healthcare applications. It is designed to satisfy two key requirements for user-unobtrusive daily ECG monitoring: reliability of ECG sensing and usability of the sensor. The system is validated through extensive evaluations. The evaluation results showed that the CardioGuard sensor reliably measure the ECG during 12 representative daily activities including diverse movement levels; 89.53% of QRS peaks were detected on average. The questionnaire-based user study with 15 participants showed that the CardioGuard sensor was comfortable and unobtrusive. Additionally, the signal-to-noise ratio test and the washing durability test were conducted to show the high-quality sensing of the proposed sensor and its physical durability in practical use, respectively. PMID:25405527

Implantable medical sensor system

DOEpatents

Darrow, Christopher B.; Satcher, Jr., Joe H.; Lane, Stephen M.; Lee, Abraham P.; Wang, Amy W.

2001-01-01

An implantable chemical sensor system for medical applications is described which permits selective recognition of an analyte using an expandable biocompatible sensor, such as a polymer, that undergoes a dimensional change in the presence of the analyte. The expandable polymer is incorporated into an electronic circuit component that changes its properties (e.g., frequency) when the polymer changes dimension. As the circuit changes its characteristics, an external interrogator transmits a signal transdermally to the transducer, and the concentration of the analyte is determined from the measured changes in the circuit. This invention may be used for minimally invasive monitoring of blood glucose levels in diabetic patients.

Active polymer materials for optical fiber CO2 sensors

NASA Astrophysics Data System (ADS)

Wysokiński, Karol; Filipowicz, Marta; Stańczyk, Tomasz; Lipiński, Stanisław; Napierała, Marek; Murawski, Michał; Nasiłowski, Tomasz

2017-04-01

CO2 optical fiber sensors based on polymer active materials are presented in this paper. Ethyl cellulose was proven to be a good candidate for a matrix material of the sensor, since it gives porous, thick and very sensitive layers. Low-cost sensors based on polymer optical fibers have been elaborated. Sensors have been examined for their sensitivity to CO2, temperature and humidity. Response time during cyclic exposures to CO2 have been also determined. Special layers exhibiting irreversible change of color during exposure to carbon dioxide have been developed. They have been verified for a possible use in smart food packaging.

All-fiber, long-active-length Fabry-Perot strain sensor.

PubMed

Pevec, Simon; Donlagic, Denis

2011-08-01

This paper presents a high-sensitivity, all-silica, all-fiber Fabry-Perot strain-sensor. The proposed sensor provides a long active length, arbitrary length of Fabry-Perot cavity, and low intrinsic temperature sensitivity. The sensor was micro-machined from purposely-developed sensor-forming fiber that is etched and directly spliced to the lead-in fiber. This manufacturing process has good potential for cost-effective, high-volume production. Its measurement range of over 3000 µε, and strain-resolution better than 1 µε were demonstrated by the application of a commercial, multimode fiber-based signal processor.

Sensor system for buried waste containment sites

DOEpatents

Smith, Ann Marie; Gardner, Bradley M.; Kostelnik, Kevin M.; Partin, Judy K.; Lancaster, Gregory D.; Pfeifer, May Catherine

2000-01-01

A sensor system is disclosed for a buried waste containment site having a bottom wall barrier and/or sidewall barriers, for containing hazardous waste. The sensor system includes one or more sensor devices disposed in one or more of the barriers for detecting a physical parameter either of the barrier itself or of the physical condition of the surrounding soils and buried waste, and for producing a signal representing the physical parameter detected. Also included is a signal processor for receiving signals produced by the sensor device and for developing information identifying the physical parameter detected, either for sounding an alarm, displaying a graphic representation of a physical parameter detected on a viewing screen and/or a hard copy printout. The sensor devices may be deployed in or adjacent the barriers at the same time the barriers are deployed and may be adapted to detect strain or cracking in the barriers, leakage of radiation through the barriers, the presence and leaking through the barriers of volatile organic compounds, or similar physical conditions.

System Wide Joint Position Sensor Fault Tolerance in Robot Systems Using Cartesian Accelerometers

NASA Technical Reports Server (NTRS)

Aldridge, Hal A.; Juang, Jer-Nan

1997-01-01

Joint position sensors are necessary for most robot control systems. A single position sensor failure in a normal robot system can greatly degrade performance. This paper presents a method to obtain position information from Cartesian accelerometers without integration. Depending on the number and location of the accelerometers. the proposed system can tolerate the loss of multiple position sensors. A solution technique suitable for real-time implementation is presented. Simulations were conducted using 5 triaxial accelerometers to recover from the loss of up to 4 joint position sensors on a 7 degree of freedom robot moving in general three dimensional space. The simulations show good estimation performance using non-ideal accelerometer measurements.

A hybrid active/passive exhaust noise control system for locomotives.

PubMed

Remington, Paul J; Knight, J Scott; Hanna, Doug; Rowley, Craig

2005-01-01

A prototype hybrid system consisting of active and passive components for controlling far-field locomotive exhaust noise has been designed, assembled, and tested on a locomotive. The system consisted of a resistive passive silencer for controlling high-frequency broadband noise and a feedforward multiple-input, multiple-output active control system for suppressing low-frequency tonal noise. The active system used ten roof-mounted bandpass speaker enclosures with 2-12-in. speakers per enclosure as actuators, eight roof-mounted electret microphones as residual sensors, and an optical tachometer that sensed locomotive engine speed as a reference sensor. The system was installed on a passenger locomotive and tested in an operating rail yard. Details of the system are described and the near-field and far-field noise reductions are compared against the design goal.

Transparent silicon strip sensors for the optical alignment of particle detector systems

NASA Astrophysics Data System (ADS)

Blum, W.; Kroha, H.; Widmann, P.

1996-02-01

Modern large-area precision tracking detectors require increasing accuracy for the alignment of their components. A novel multi-point laser alignment system has been developed for such applications. The position of detector components with respect to reference laser beams is monitored by semi-transparent optical position sensors which work on the principle of silicon strip photodiodes. Two types of custom designed transparent strip sensors, based on crystalline and on amorphous silicon as active material, have been studied. The sensors are optimized for the typical diameters of collimated laser beams of 3-5 mm over distances of 10-20 m. They provide very high position resolution, on the order of 1 μm, uniformly over a wide measurement range of several centimeters. The preparation of the sensor surfaces requires special attention in order to achieve high light transmittance and minimum distortion of the traversing laser beams. At selected wavelengths, produced by laser diodes, transmission rates above 90% have been achieved. This allows to position more than 30 sensors along one laser beam. The sensors will be equipped with custom designed integrated readout electronics.

Wireless energizing system for an automated implantable sensor.

PubMed

Swain, Biswaranjan; Nayak, Praveen P; Kar, Durga P; Bhuyan, Satyanarayan; Mishra, Laxmi P

2016-07-01

The wireless drive of an automated implantable electronic sensor has been explored for health monitoring applications. The proposed system comprises of an automated biomedical sensing system which is energized through resonant inductive coupling. The implantable sensor unit is able to monitor the body temperature parameter and sends back the corresponding telemetry data wirelessly to the data recoding unit. It has been observed that the wireless power delivery system is capable of energizing the automated biomedical implantable electronic sensor placed over a distance of 3 cm from the power transmitter with an energy transfer efficiency of 26% at the operating resonant frequency of 562 kHz. This proposed method ensures real-time monitoring of different human body temperatures around the clock. The monitored temperature data have been compared with a calibrated temperature measurement system to ascertain the accuracy of the proposed system. The investigated technique can also be useful for monitoring other body parameters such as blood pressure, bladder pressure, and physiological signals of the patient in vivo using various implantable sensors.

Wireless energizing system for an automated implantable sensor

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

Swain, Biswaranjan; Nayak, Praveen P.; Kar, Durga P.

The wireless drive of an automated implantable electronic sensor has been explored for health monitoring applications. The proposed system comprises of an automated biomedical sensing system which is energized through resonant inductive coupling. The implantable sensor unit is able to monitor the body temperature parameter and sends back the corresponding telemetry data wirelessly to the data recoding unit. It has been observed that the wireless power delivery system is capable of energizing the automated biomedical implantable electronic sensor placed over a distance of 3 cm from the power transmitter with an energy transfer efficiency of 26% at the operating resonantmore » frequency of 562 kHz. This proposed method ensures real-time monitoring of different human body temperatures around the clock. The monitored temperature data have been compared with a calibrated temperature measurement system to ascertain the accuracy of the proposed system. The investigated technique can also be useful for monitoring other body parameters such as blood pressure, bladder pressure, and physiological signals of the patient in vivo using various implantable sensors.« less

Dual-Actuator Active Vibration-Control System

NASA Technical Reports Server (NTRS)

Kascak, Albert F.; Kiraly, Louis J.; Montague, Gerald T.; Palazzolo, Alan B.; Manchala, Daniel

1994-01-01

Dual-actuator active vibration-control (DAAVC) system is developmental system of type described in "Active Vibration Dampers for Rotating Machinery" (LEW-15427). System features sensors and actuators positioned and oriented at bearings to measure and counteract vibrations of shaft along either of two axes perpendicular to axis of rotation. Effective in damping vibrations of helicopter-engine test stand, making it safer to operate engine at speeds near and above first resonance of engine/test-stand system. Opens new opportunities for engine designers to draw more power from engine, and concept applicable to other rotating machines.

Fiber-optic push-pull sensor systems

NASA Technical Reports Server (NTRS)

Gardner, David L.; Brown, David A.; Garrett, Steven L.

1991-01-01

Fiber-optic push-pull sensors are those which exploit the intrinsically differential nature of an interferometer with concommitant benefits in common-mode rejection of undesired effects. Several fiber-optic accelerometer and hydrophone designs are described. Additionally, the recent development at the Naval Postgraduate School of a passive low-cost interferometric signal demodulator permits the development of economical fiber-optic sensor systems.

Optical Breath Gas Sensor for Extravehicular Activity Application

NASA Technical Reports Server (NTRS)

Wood, William R.; Casias, Miguel E.; Vakhtin, Andrei B.; Pilgrim, Jeffrey S.; Chullen, Cinda; Falconi, Eric A.; McMillin, Summer

2013-01-01

The function of the infrared gas transducer used during extravehicular activity in the current space suit is to measure and report the concentration of carbon dioxide (CO2) in the ventilation loop. The next generation portable life support system (PLSS) requires next generation CO2 sensing technology with performance beyond that presently in use on the Space Shuttle/International Space Station extravehicular mobility unit (EMU). Accommodation within space suits demands that optical sensors meet stringent size, weight, and power requirements. A laser diode spectrometer based on wavelength modulation spectroscopy is being developed for this purpose by Vista Photonics, Inc. Two prototype devices were delivered to NASA Johnson Space Center (JSC) in September 2011. The sensors incorporate a laser diode-based CO2 channel that also includes an incidental water vapor (humidity) measurement and a separate oxygen channel using a vertical cavity surface emitting laser. Both prototypes are controlled digitally with a field-programmable gate array/microcontroller architecture. The present development extends and upgrades the earlier hardware to the Advanced PLSS 2.0 test article being constructed and tested at JSC. Various improvements to the electronics and gas sampling are being advanced by this project. The combination of low power electronics with the performance of a long wavelength laser spectrometer enables multi-gas sensors with significantly increased performance over that presently offered in the EMU.

A Prototype Flood Early Warning SensorWeb System for Namibia

NASA Astrophysics Data System (ADS)

Sohlberg, R. A.; Mandl, D.; Frye, S. W.; Cappelaere, P. G.; Szarzynski, J.; Policelli, F.; van Langenhove, G.

2010-12-01

During the past two years, there have been extensive floods in the country of Namibia, Africa which have affected up to a quarter of the population. Via a collaboration between a group funded by the Earth Science Technology Office (ESTO) at NASA that has been performing various SensorWeb prototyping activities for disasters, the Department of Hydrology in Namibia and the United Nations Space-based Information for Disaster and Emergency Response (UN-SPIDER) , experiments were conducted on how to apply various satellite resources integrated into a SensorWeb architecture along with in-situ sensors such as river gauges and rain gauges into a flood early warning system. The SensorWeb includes a global flood model and a higher resolution basin specific flood model. Furthermore, flood extent and status is monitored by optical and radar types of satellites and integrated via some automation. We have taken a practical approach to find out how to create a working system by selectively using the components that provide good results. The vision for the future is to combine this with the country side dwelling unit data base to create risk maps that provide specific warnings to houses within high risk areas based on near term predictions. This presentation will show some of the highlights of the effort thus far plus our future plans.

Electron beam diagnostic system using computed tomography and an annular sensor

DOEpatents

Elmer, John W.; Teruya, Alan T.

2014-07-29

A system for analyzing an electron beam including a circular electron beam diagnostic sensor adapted to receive the electron beam, the circular electron beam diagnostic sensor having a central axis; an annular sensor structure operatively connected to the circular electron beam diagnostic sensor, wherein the sensor structure receives the electron beam; a system for sweeping the electron beam radially outward from the central axis of the circular electron beam diagnostic sensor to the annular sensor structure wherein the electron beam is intercepted by the annular sensor structure; and a device for measuring the electron beam that is intercepted by the annular sensor structure.

Replaceable Sensor System for Bioreactor Monitoring

NASA Technical Reports Server (NTRS)

Mayo, Mike; Savoy, Steve; Bruno, John

2006-01-01

A sensor system was proposed that would monitor spaceflight bioreactor parameters. Not only will this technology be invaluable in the space program for which it was developed, it will find applications in medical science and industrial laboratories as well. Using frequency-domain-based fluorescence lifetime technology, the sensor system will be able to detect changes in fluorescence lifetime quenching that results from displacement of fluorophorelabeled receptors bound to target ligands. This device will be used to monitor and regulate bioreactor parameters including glucose, pH, oxygen pressure (pO2), and carbon dioxide pressure (pCO2). Moreover, these biosensor fluorophore receptor-quenching complexes can be designed to further detect and monitor for potential biohazards, bioproducts, or bioimpurities. Biosensors used to detect biological fluid constituents have already been developed that employ a number of strategies, including invasive microelectrodes (e.g., dark electrodes), optical techniques including fluorescence, and membrane permeable systems based on osmotic pressure. Yet the longevity of any of these sensors does not meet the demands of extended use in spacecraft habitat or bioreactor monitoring. It was therefore necessary to develop a sensor platform that could determine not only fluid variables such as glucose concentration, pO2, pCO2, and pH but can also regulate these fluid variables with controlled feedback loop.

What Does Big Data Mean for Wearable Sensor Systems?

PubMed Central

Lovell, N. H.; Yang, G. Z.; Horsch, A.; Lukowicz, P.; Murrugarra, L.; Marschollek, M.

2014-01-01

Summary Objectives The aim of this paper is to discuss how recent developments in the field of big data may potentially impact the future use of wearable sensor systems in healthcare. Methods The article draws on the scientific literature to support the opinions presented by the IMIA Wearable Sensors in Healthcare Working Group. Results The following is discussed: the potential for wearable sensors to generate big data; how complementary technologies, such as a smartphone, will augment the concept of a wearable sensor and alter the nature of the monitoring data created; how standards would enable sharing of data and advance scientific progress. Importantly, attention is drawn to statistical inference problems for which big datasets provide little assistance, or may hinder the identification of a useful solution. Finally, a discussion is presented on risks to privacy and possible negative consequences arising from intensive wearable sensor monitoring. Conclusions Wearable sensors systems have the potential to generate datasets which are currently beyond our capabilities to easily organize and interpret. In order to successfully utilize wearable sensor data to infer wellbeing, and enable proactive health management, standards and ontologies must be developed which allow for data to be shared between research groups and between commercial systems, promoting the integration of these data into health information systems. However, policy and regulation will be required to ensure that the detailed nature of wearable sensor data is not misused to invade privacies or prejudice against individuals. PMID:25123733

A closed-loop system for frequency tracking of piezoresistive cantilever sensors

NASA Astrophysics Data System (ADS)

Wasisto, Hutomo Suryo; Zhang, Qing; Merzsch, Stephan; Waag, Andreas; Peiner, Erwin

2013-05-01

A closed loop circuit capable of tracking resonant frequencies for MEMS-based piezoresistive cantilever resonators is developed in this work. The proposed closed-loop system is mainly based on a phase locked loop (PLL) circuit. In order to lock onto the resonant frequency of the resonator, an actuation signal generated from a voltage-controlled oscillator (VCO) is locked to the phase of the input reference signal of the cantilever sensor. In addition to the PLL component, an instrumentation amplifier and an active low pass filter (LPF) are connected to the system for gaining the amplitude and reducing the noise of the cantilever output signals. The LPF can transform a rectangular signal into a sinusoidal signal with voltage amplitudes ranging from 5 to 10 V which are sufficient for a piezoactuator input (i.e., maintaining a large output signal of the cantilever sensor). To demonstrate the functionality of the system, a self-sensing silicon cantilever resonator with a built-in piezoresistive Wheatstone bridge is fabricated and integrated with the circuit. A piezoactuator is utilized for actuating the cantilever into resonance. Implementation of this closed loop system is used to track the resonant frequency of a silicon cantilever-based sensor resonating at 9.4 kHz under a cross-sensitivity test of ambient temperature. The changes of the resonant frequency are interpreted using a frequency counter connected to the system. From the experimental results, the temperature sensitivity and coefficient of the employed sensor are 0.3 Hz/°C and 32.8 ppm/°C, respectively. The frequency stability of the system can reach up to 0.08 Hz. The development of this system will enable real-time nanoparticle monitoring systems and provide a miniaturization of the instrumentation modules for cantilever-based nanoparticle detectors.

Wireless Integrated Microelectronic Vacuum Sensor System

NASA Technical Reports Server (NTRS)

Krug, Eric; Philpot, Brian; Trott, Aaron; Lawrence, Shaun

2013-01-01

NASA Stennis Space Center's (SSC's) large rocket engine test facility requires the use of liquid propellants, including the use of cryogenic fluids like liquid hydrogen as fuel, and liquid oxygen as an oxidizer (gases which have been liquefied at very low temperatures). These fluids require special handling, storage, and transfer technology. The biggest problem associated with transferring cryogenic liquids is product loss due to heat transfer. Vacuum jacketed piping is specifically designed to maintain high thermal efficiency so that cryogenic liquids can be transferred with minimal heat transfer. A vacuum jacketed pipe is essentially two pipes in one. There is an inner carrier pipe, in which the cryogenic liquid is actually transferred, and an outer jacket pipe that supports and seals the vacuum insulation, forming the "vacuum jacket." The integrity of the vacuum jacketed transmission lines that transfer the cryogenic fluid from delivery barges to the test stand must be maintained prior to and during engine testing. To monitor the vacuum in these vacuum jacketed transmission lines, vacuum gauge readings are used. At SSC, vacuum gauge measurements are done on a manual rotation basis with two technicians, each using a handheld instrument. Manual collection of vacuum data is labor intensive and uses valuable personnel time. Additionally, there are times when personnel cannot collect the data in a timely fashion (i.e., when a leak is detected, measurements must be taken more often). Additionally, distribution of this data to all interested parties can be cumbersome. To simplify the vacuum-gauge data collection process, automate the data collection, and decrease the labor costs associated with acquiring these measurements, an automated system that monitors the existing gauges was developed by Invocon, Inc. For this project, Invocon developed a Wireless Integrated Microelectronic Vacuum Sensor System (WIMVSS) that provides the ability to gather vacuum

Sense, decide, act, communicate (SDAC): next generation of smart sensor systems

NASA Astrophysics Data System (ADS)

Berry, Nina; Davis, Jesse; Ko, Teresa H.; Kyker, Ron; Pate, Ron; Stark, Doug; Stinnett, Regan; Baker, James; Cushner, Adam; Van Dyke, Colin; Kyckelhahn, Brian

2004-09-01

The recent war on terrorism and increased urban warfare has been a major catalysis for increased interest in the development of disposable unattended wireless ground sensors. While the application of these sensors to hostile domains has been generally governed by specific tasks, this research explores a unique paradigm capitalizing on the fundamental functionality related to sensor systems. This functionality includes a sensors ability to Sense - multi-modal sensing of environmental events, Decide - smart analysis of sensor data, Act - response to environmental events, and Communication - internal to system and external to humans (SDAC). The main concept behind SDAC sensor systems is to integrate the hardware, software, and networking to generate 'knowledge and not just data'. This research explores the usage of wireless SDAC units to collectively make up a sensor system capable of persistent, adaptive, and autonomous behavior. These systems are base on the evaluation of scenarios and existing systems covering various domains. This paper presents a promising view of sensor network characteristics, which will eventually yield smart (intelligent collectives) network arrays of SDAC sensing units generally applicable to multiple related domains. This paper will also discuss and evaluate the demonstration system developed to test the concepts related to SDAC systems.

UHF wearable battery free sensor module for activity and falling detection.

PubMed

Nam Trung Dang; Thang Viet Tran; Wan-Young Chung

2016-08-01

Falling is one of the most serious medical and social problems in aging population. Therefore taking care of the elderly by detecting activity and falling for preventing and mitigating the injuries caused by falls needs to be concerned. This study proposes a wearable, wireless, battery free ultra-high frequency (UHF) smart sensor tag module for falling and activity detection. The proposed tag is powered by UHF RF wave from reader and read by a standard UHF Electronic Product Code (EPC) Class-1 Generation-2 reader. The battery free sensor module could improve the wearability of the wireless device. The combination of accelerometer signal and received signal strength indication (RSSI) from a reader in the passive smart sensor tag detect the activity and falling of the elderly very successfully. The fabricated smart sensor tag module has an operating range of up to 2.5m and conducting in real-time activity and falling detection.

Sensor-Based Human Activity Recognition in a Multi-user Scenario

NASA Astrophysics Data System (ADS)

Wang, Liang; Gu, Tao; Tao, Xianping; Lu, Jian

Existing work on sensor-based activity recognition focuses mainly on single-user activities. However, in real life, activities are often performed by multiple users involving interactions between them. In this paper, we propose Coupled Hidden Markov Models (CHMMs) to recognize multi-user activities from sensor readings in a smart home environment. We develop a multimodal sensing platform and present a theoretical framework to recognize both single-user and multi-user activities. We conduct our trace collection done in a smart home, and evaluate our framework through experimental studies. Our experimental result shows that we achieve an average accuracy of 85.46% with CHMMs.

Got Point Clouds: Characterizing Canopy Structure With Active and Passive Sensors

NASA Astrophysics Data System (ADS)

Popescu, S. C.; Malambo, L.; Sheridan, R.; Putman, E.; Murray, S.; Rooney, W.; Rajan, N.

2016-12-01

Unmanned Aerial Systems (UAS) provide the means to acquire highly customized aerial data at local scale with a multitude of sensors. UAS allow us to obtain affordably repeated observations of canopy structure for agricultural and natural resources applications by using passive optical sensors, such as cameras and photogrammetric techniques, and active sensors, such as lidar (Light Detection and Ranging). The objectives of this presentation are to: (1) offer a brief overview of UAS used for agriculture and natural resources studies, (2) describe experiences in conducting agriculture phenotyping and forest vegetation measurements, and (3) give details on the methodology developed for image and lidar data processing for characterizing the three dimensional structure of plant canopies. The UAS types used for this purpose included rotary platforms, such as quadcopters, hexacopters, and octocopters, with a payload capacity of up to 19 lbs. The sensors that collected data over two crop seasons include multispectral cameras in the visible color spectrum and near infrared, and UAS-lidar. For ground reference data we used terrestrial lidar scanners and field measurements. Results comparing UAS and terrestrial measurements show high correlation and open new areas of scientific investigation of crop canopies previously not possible with affordable techniques.

Sensor network based vehicle classification and license plate identification system

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

Frigo, Janette Rose; Brennan, Sean M; Rosten, Edward J

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

Integrated IR sensors

NASA Astrophysics Data System (ADS)

Tom, Michael; Trujillo, Edward

1994-06-01

Integrated infrared (IR) sensors which exploit modular avionics concepts can provide features such as operational flexibility, enhanced stealthiness, and ease of maintenance to meet the demands of tactical, airborne sensor systems. On-board, tactical airborne sensor systems perform target acquisition, tracking, identification, threat warning, missile launch detection, and ground mapping in support of situation awareness, self-defense, navigation, target attack, weapon support, and reconnaissance activities. The use of sensor suites for future tactical aircraft such as US Air Force's multirole fighter require a blend of sensor inputs and outputs that may vary over time. It is expected that special-role units of these tactical aircraft will be formed to conduct tasks and missions such as anti-shipping, reconnaissance, or suppression of enemy air defenses.

On the Use of Sensor Fusion to Reduce the Impact of Rotational and Additive Noise in Human Activity Recognition

PubMed Central

Banos, Oresti; Damas, Miguel; Pomares, Hector; Rojas, Ignacio

2012-01-01

The main objective of fusion mechanisms is to increase the individual reliability of the systems through the use of the collectivity knowledge. Moreover, fusion models are also intended to guarantee a certain level of robustness. This is particularly required for problems such as human activity recognition where runtime changes in the sensor setup seriously disturb the reliability of the initial deployed systems. For commonly used recognition systems based on inertial sensors, these changes are primarily characterized as sensor rotations, displacements or faults related to the batteries or calibration. In this work we show the robustness capabilities of a sensor-weighted fusion model when dealing with such disturbances under different circumstances. Using the proposed method, up to 60% outperformance is obtained when a minority of the sensors are artificially rotated or degraded, independent of the level of disturbance (noise) imposed. These robustness capabilities also apply for any number of sensors affected by a low to moderate noise level. The presented fusion mechanism compensates the poor performance that otherwise would be obtained when just a single sensor is considered. PMID:22969386

On the use of sensor fusion to reduce the impact of rotational and additive noise in human activity recognition.

PubMed

Banos, Oresti; Damas, Miguel; Pomares, Hector; Rojas, Ignacio

2012-01-01

The main objective of fusion mechanisms is to increase the individual reliability of the systems through the use of the collectivity knowledge. Moreover, fusion models are also intended to guarantee a certain level of robustness. This is particularly required for problems such as human activity recognition where runtime changes in the sensor setup seriously disturb the reliability of the initial deployed systems. For commonly used recognition systems based on inertial sensors, these changes are primarily characterized as sensor rotations, displacements or faults related to the batteries or calibration. In this work we show the robustness capabilities of a sensor-weighted fusion model when dealing with such disturbances under different circumstances. Using the proposed method, up to 60% outperformance is obtained when a minority of the sensors are artificially rotated or degraded, independent of the level of disturbance (noise) imposed. These robustness capabilities also apply for any number of sensors affected by a low to moderate noise level. The presented fusion mechanism compensates the poor performance that otherwise would be obtained when just a single sensor is considered.

Sensor Selection and Optimization for Health Assessment of Aerospace Systems

NASA Technical Reports Server (NTRS)

Maul, William A.; Kopasakis, George; Santi, Louis M.; Sowers, Thomas S.; Chicatelli, Amy

2007-01-01

Aerospace systems are developed similarly to other large-scale systems through a series of reviews, where designs are modified as system requirements are refined. For space-based systems few are built and placed into service. These research vehicles have limited historical experience to draw from and formidable reliability and safety requirements, due to the remote and severe environment of space. Aeronautical systems have similar reliability and safety requirements, and while these systems may have historical information to access, commercial and military systems require longevity under a range of operational conditions and applied loads. Historically, the design of aerospace systems, particularly the selection of sensors, is based on the requirements for control and performance rather than on health assessment needs. Furthermore, the safety and reliability requirements are met through sensor suite augmentation in an ad hoc, heuristic manner, rather than any systematic approach. A review of the current sensor selection practice within and outside of the aerospace community was conducted and a sensor selection architecture is proposed that will provide a justifiable, dependable sensor suite to address system health assessment requirements.

Sensor Selection and Optimization for Health Assessment of Aerospace Systems

NASA Technical Reports Server (NTRS)

Maul, William A.; Kopasakis, George; Santi, Louis M.; Sowers, Thomas S.; Chicatelli, Amy

2008-01-01

Aerospace systems are developed similarly to other large-scale systems through a series of reviews, where designs are modified as system requirements are refined. For space-based systems few are built and placed into service these research vehicles have limited historical experience to draw from and formidable reliability and safety requirements, due to the remote and severe environment of space. Aeronautical systems have similar reliability and safety requirements, and while these systems may have historical information to access, commercial and military systems require longevity under a range of operational conditions and applied loads. Historically, the design of aerospace systems, particularly the selection of sensors, is based on the requirements for control and performance rather than on health assessment needs. Furthermore, the safety and reliability requirements are met through sensor suite augmentation in an ad hoc, heuristic manner, rather than any systematic approach. A review of the current sensor selection practice within and outside of the aerospace community was conducted and a sensor selection architecture is proposed that will provide a justifiable, defendable sensor suite to address system health assessment requirements.

Fast Low-Cost Multiple Sensor Readout System

DOEpatents

Carter-Lewis, David; Krennich, Frank; Le Bohec, Stephane; Petry, Dirk; Sleege, Gary

2004-04-06

A low resolution data acquisition system is presented. The data acquisition system has a plurality of readout modules serially connected to a controller. Each readout module has a FPGA in communication with analog to digital (A/D) converters, which are connected to sensors. The A/D converter has eight bit or lower resolution. The FPGA detects when a command is addressed to it and commands the A/D converters to convert analog sensor data into digital data. The digital data is sent on a high speed serial communication bus to the controller. A graphical display is used in one embodiment to indicate if a sensor reading is outside of a predetermined range.

Thermal protection system ablation sensor

NASA Technical Reports Server (NTRS)

Gorbunov, Sergey (Inventor); Martinez, Edward R. (Inventor); Scott, James B. (Inventor); Oishi, Tomomi (Inventor); Fu, Johnny (Inventor); Mach, Joseph G. (Inventor); Santos, Jose B. (Inventor)

2011-01-01

An isotherm sensor tracks space vehicle temperatures by a thermal protection system (TPS) material during vehicle re-entry as a function of time, and surface recession through calibration, calculation, analysis and exposed surface modeling. Sensor design includes: two resistive conductors, wound around a tube, with a first end of each conductor connected to a constant current source, and second ends electrically insulated from each other by a selected material that becomes an electrically conductive char at higher temperatures to thereby complete an electrical circuit. The sensor conductors become shorter as ablation proceeds and reduced resistance in the completed electrical circuit (proportional to conductor length) is continually monitored, using measured end-to-end voltage change or current in the circuit. Thermocouple and/or piezoelectric measurements provide consistency checks on local temperatures.

A Multiple Sensor Machine Vision System Technology for the Hardwood

Treesearch