Recent Progress in Technologies for Tactile Sensors.

PubMed

Chi, Cheng; Sun, Xuguang; Xue, Ning; Li, Tong; Liu, Chang

2018-03-22

Over the last two decades, considerable scientific and technological efforts have been devoted to developing tactile sensing based on a variety of transducing mechanisms, with prospective applications in many fields such as human-machine interaction, intelligent robot tactile control and feedback, and tactile sensorized minimally invasive surgery. This paper starts with an introduction of human tactile systems, followed by a presentation of the basic demands of tactile sensors. State-of-the-art tactile sensors are reviewed in terms of their diverse sensing mechanisms, design consideration, and material selection. Subsequently, typical performances of the sensors, along with their advantages and disadvantages, are compared and analyzed. Two major potential applications of tactile sensing systems are discussed in detail. Lastly, we propose prospective research directions and market trends of tactile sensing systems.

A Novel Method to Increase LinLog CMOS Sensors’ Performance in High Dynamic Range Scenarios

PubMed Central

Martínez-Sánchez, Antonio; Fernández, Carlos; Navarro, Pedro J.; Iborra, Andrés

2011-01-01

Images from high dynamic range (HDR) scenes must be obtained with minimum loss of information. For this purpose it is necessary to take full advantage of the quantification levels provided by the CCD/CMOS image sensor. LinLog CMOS sensors satisfy the above demand by offering an adjustable response curve that combines linear and logarithmic responses. This paper presents a novel method to quickly adjust the parameters that control the response curve of a LinLog CMOS image sensor. We propose to use an Adaptive Proportional-Integral-Derivative controller to adjust the exposure time of the sensor, together with control algorithms based on the saturation level and the entropy of the images. With this method the sensor’s maximum dynamic range (120 dB) can be used to acquire good quality images from HDR scenes with fast, automatic adaptation to scene conditions. Adaptation to a new scene is rapid, with a sensor response adjustment of less than eight frames when working in real time video mode. At least 67% of the scene entropy can be retained with this method. PMID:22164083

A Brief Review of the Need for Robust Smart Wireless Sensor Systems for Future Propulsion Systems, Distributed Engine Controls, and Propulsion Health Management

NASA Technical Reports Server (NTRS)

Hunter, Gary W.; Behbahani, Alireza

2012-01-01

Smart Sensor Systems with wireless capability operational in high temperature, harsh environments are a significant component in enabling future propulsion systems to meet a range of increasingly demanding requirements. These propulsion systems must incorporate technology that will monitor engine component conditions, analyze the incoming data, and modify operating parameters to optimize propulsion system operations. This paper discusses the motivation towards the development of high temperature, smart wireless sensor systems that include sensors, electronics, wireless communication, and power. The challenges associated with the use of traditional wired sensor systems will be reviewed and potential advantages of Smart Sensor Systems will be discussed. A brief review of potential applications for wireless smart sensor networks and their potential impact on propulsion system operation, with emphasis on Distributed Engine Control and Propulsion Health Management, will be given. A specific example related to the development of high temperature Smart Sensor Systems based on silicon carbide electronics will be discussed. It is concluded that the development of a range of robust smart wireless sensor systems are a foundation for future development of intelligent propulsion systems with enhanced capabilities.

Using Bayesian Inference Framework towards Identifying Gas Species and Concentration from High Temperature Resistive Sensor Array Data

DOE PAGES

Liu, Yixin; Zhou, Kai; Lei, Yu

2015-01-01

High temperature gas sensors have been highly demanded for combustion process optimization and toxic emissions control, which usually suffer from poor selectivity. In order to solve this selectivity issue and identify unknown reducing gas species (CO, CH 4 , and CH 8 ) and concentrations, a high temperature resistive sensor array data set was built in this study based on 5 reported sensors. As each sensor showed specific responses towards different types of reducing gas with certain concentrations, based on which calibration curves were fitted, providing benchmark sensor array response database, then Bayesian inference framework was utilized to process themore » sensor array data and build a sample selection program to simultaneously identify gas species and concentration, by formulating proper likelihood between input measured sensor array response pattern of an unknown gas and each sampled sensor array response pattern in benchmark database. This algorithm shows good robustness which can accurately identify gas species and predict gas concentration with a small error of less than 10% based on limited amount of experiment data. These features indicate that Bayesian probabilistic approach is a simple and efficient way to process sensor array data, which can significantly reduce the required computational overhead and training data.« less

An Energy-Efficient ASIC for Wireless Body Sensor Networks in Medical Applications.

PubMed

Xiaoyu Zhang; Hanjun Jiang; Lingwei Zhang; Chun Zhang; Zhihua Wang; Xinkai Chen

2010-02-01

An energy-efficient application-specific integrated circuit (ASIC) featured with a work-on-demand protocol is designed for wireless body sensor networks (WBSNs) in medical applications. Dedicated for ultra-low-power wireless sensor nodes, the ASIC consists of a low-power microcontroller unit (MCU), a power-management unit (PMU), reconfigurable sensor interfaces, communication ports controlling a wireless transceiver, and an integrated passive radio-frequency (RF) receiver with energy harvesting ability. The MCU, together with the PMU, provides quite flexible communication and power-control modes for energy-efficient operations. The always-on passive RF receiver with an RF energy harvesting block offers the sensor nodes the capability of work-on-demand with zero standby power. Fabricated in standard 0.18-¿m complementary metal-oxide semiconductor technology, the ASIC occupies a die area of 2 mm × 2.5 mm. A wireless body sensor network sensor-node prototype using this ASIC only consumes < 10-nA current under the passive standby mode, and < 10 ¿A under the active standby mode, when supplied by a 3-V battery.

Identification of Hot Moments and Hot Spots for Real-Time Adaptive Control of Multi-scale Environmental Sensor Networks

NASA Astrophysics Data System (ADS)

Wietsma, T.; Minsker, B. S.

2012-12-01

Increased sensor throughput combined with decreasing hardware costs has led to a disruptive growth in data volume. This disruption, popularly termed "the data deluge," has placed new demands for cyberinfrastructure and information technology skills among researchers in many academic fields, including the environmental sciences. Adaptive sampling has been well established as an effective means of improving network resource efficiency (energy, bandwidth) without sacrificing sample set quality relative to traditional uniform sampling. However, using adaptive sampling for the explicit purpose of improving resolution over events -- situations displaying intermittent dynamics and unique hydrogeological signatures -- is relatively new. In this paper, we define hot spots and hot moments in terms of sensor signal activity as measured through discrete Fourier analysis. Following this frequency-based approach, we apply the Nyquist-Shannon sampling theorem, a fundamental contribution from signal processing that led to the field of information theory, for analysis of uni- and multivariate environmental signal data. In the scope of multi-scale environmental sensor networks, we present several sampling control algorithms, derived from the Nyquist-Shannon theorem, that operate at local (field sensor), regional (base station for aggregation of field sensor data), and global (Cloud-based, computationally intensive models) scales. Evaluated over soil moisture data, results indicate significantly greater sample density during precipitation events while reducing overall sample volume. Using these algorithms as indicators rather than control mechanisms, we also discuss opportunities for spatio-temporal modeling as a tool for planning/modifying sensor network deployments. Locally adaptive model based on Nyquist-Shannon sampling theorem Pareto frontiers for local, regional, and global models relative to uniform sampling. Objectives are (1) overall sampling efficiency and (2) sampling efficiency during hot moments as identified using heuristic approach.

Spectrum Sharing Based on a Bertrand Game in Cognitive Radio Sensor Networks

PubMed Central

Zeng, Biqing; Zhang, Chi; Hu, Pianpian; Wang, Shengyu

2017-01-01

In the study of power control and allocation based on pricing, the utility of secondary users is usually studied from the perspective of the signal to noise ratio. The study of secondary user utility from the perspective of communication demand can not only promote the secondary users to meet the maximum communication needs, but also to maximize the utilization of spectrum resources, however, research in this area is lacking, so from the viewpoint of meeting the demand of network communication, this paper designs a two stage model to solve spectrum leasing and allocation problem in cognitive radio sensor networks (CRSNs). In the first stage, the secondary base station collects the secondary network communication requirements, and rents spectrum resources from several primary base stations using the Bertrand game to model the transaction behavior of the primary base station and secondary base station. The second stage, the subcarriers and power allocation problem of secondary base stations is defined as a nonlinear programming problem to be solved based on Nash bargaining. The simulation results show that the proposed model can satisfy the communication requirements of each user in a fair and efficient way compared to other spectrum sharing schemes. PMID:28067850

Software Defined Networking for Improved Wireless Sensor Network Management: A Survey

PubMed Central

Ndiaye, Musa; Hancke, Gerhard P.; Abu-Mahfouz, Adnan M.

2017-01-01

Wireless sensor networks (WSNs) are becoming increasingly popular with the advent of the Internet of things (IoT). Various real-world applications of WSNs such as in smart grids, smart farming and smart health would require a potential deployment of thousands or maybe hundreds of thousands of sensor nodes/actuators. To ensure proper working order and network efficiency of such a network of sensor nodes, an effective WSN management system has to be integrated. However, the inherent challenges of WSNs such as sensor/actuator heterogeneity, application dependency and resource constraints have led to challenges in implementing effective traditional WSN management. This difficulty in management increases as the WSN becomes larger. Software Defined Networking (SDN) provides a promising solution in flexible management WSNs by allowing the separation of the control logic from the sensor nodes/actuators. The advantage with this SDN-based management in WSNs is that it enables centralized control of the entire WSN making it simpler to deploy network-wide management protocols and applications on demand. This paper highlights some of the recent work on traditional WSN management in brief and reviews SDN-based management techniques for WSNs in greater detail while drawing attention to the advantages that SDN brings to traditional WSN management. This paper also investigates open research challenges in coming up with mechanisms for flexible and easier SDN-based WSN configuration and management. PMID:28471390

Software Defined Networking for Improved Wireless Sensor Network Management: A Survey.

PubMed

Ndiaye, Musa; Hancke, Gerhard P; Abu-Mahfouz, Adnan M

2017-05-04

Wireless sensor networks (WSNs) are becoming increasingly popular with the advent of the Internet of things (IoT). Various real-world applications of WSNs such as in smart grids, smart farming and smart health would require a potential deployment of thousands or maybe hundreds of thousands of sensor nodes/actuators. To ensure proper working order and network efficiency of such a network of sensor nodes, an effective WSN management system has to be integrated. However, the inherent challenges of WSNs such as sensor/actuator heterogeneity, application dependency and resource constraints have led to challenges in implementing effective traditional WSN management. This difficulty in management increases as the WSN becomes larger. Software Defined Networking (SDN) provides a promising solution in flexible management WSNs by allowing the separation of the control logic from the sensor nodes/actuators. The advantage with this SDN-based management in WSNs is that it enables centralized control of the entire WSN making it simpler to deploy network-wide management protocols and applications on demand. This paper highlights some of the recent work on traditional WSN management in brief and reviews SDN-based management techniques for WSNs in greater detail while drawing attention to the advantages that SDN brings to traditional WSN management. This paper also investigates open research challenges in coming up with mechanisms for flexible and easier SDN-based WSN configuration and management.

Advanced end-to-end fiber optic sensing systems for demanding environments

NASA Astrophysics Data System (ADS)

Black, Richard J.; Moslehi, Behzad

2010-09-01

Optical fibers are small-in-diameter, light-in-weight, electromagnetic-interference immune, electrically passive, chemically inert, flexible, embeddable into different materials, and distributed-sensing enabling, and can be temperature and radiation tolerant. With appropriate processing and/or packaging, they can be very robust and well suited to demanding environments. In this paper, we review a range of complete end-to-end fiber optic sensor systems that IFOS has developed comprising not only (1) packaged sensors and mechanisms for integration with demanding environments, but (2) ruggedized sensor interrogators, and (3) intelligent decision aid algorithms software systems. We examine the following examples: " Fiber Bragg Grating (FBG) optical sensors systems supporting arrays of environmentally conditioned multiplexed FBG point sensors on single or multiple optical fibers: In conjunction with advanced signal processing, decision aid algorithms and reasoners, FBG sensor based structural health monitoring (SHM) systems are expected to play an increasing role in extending the life and reducing costs of new generations of aerospace systems. Further, FBG based structural state sensing systems have the potential to considerably enhance the performance of dynamic structures interacting with their environment (including jet aircraft, unmanned aerial vehicles (UAVs), and medical or extravehicular space robots). " Raman based distributed temperature sensing systems: The complete length of optical fiber acts as a very long distributed sensor which may be placed down an oil well or wrapped around a cryogenic tank.

A solar charge and discharge controller for wireless sensor nodes

NASA Astrophysics Data System (ADS)

Dang, Yibo; Shen, Shu

2018-02-01

Aiming at the energy supply problem that restricts the life of wireless sensor nodes, a solar energy charge and discharge controller suitable for wireless sensor nodes is designed in this paper. A Microcontroller is used as the core of the solar charge and discharge controller. The software of the solar charge and discharge controller adopts the C language to realize the program of the main control module. Firstly, the function of monitoring solar panel voltage and lithium battery voltage are simulated by Protel software, and the charge time is tested in cloudy and overcast outdoor environment. The results of the experiment show that our controller meets the power supply demand of wireless sensor nodes.

Multi-hop routing mechanism for reliable sensor computing.

PubMed

Chen, Jiann-Liang; Ma, Yi-Wei; Lai, Chia-Ping; Hu, Chia-Cheng; Huang, Yueh-Min

2009-01-01

Current research on routing in wireless sensor computing concentrates on increasing the service lifetime, enabling scalability for large number of sensors and supporting fault tolerance for battery exhaustion and broken nodes. A sensor node is naturally exposed to various sources of unreliable communication channels and node failures. Sensor nodes have many failure modes, and each failure degrades the network performance. This work develops a novel mechanism, called Reliable Routing Mechanism (RRM), based on a hybrid cluster-based routing protocol to specify the best reliable routing path for sensor computing. Table-driven intra-cluster routing and on-demand inter-cluster routing are combined by changing the relationship between clusters for sensor computing. Applying a reliable routing mechanism in sensor computing can improve routing reliability, maintain low packet loss, minimize management overhead and save energy consumption. Simulation results indicate that the reliability of the proposed RRM mechanism is around 25% higher than that of the Dynamic Source Routing (DSR) and ad hoc On-demand Distance Vector routing (AODV) mechanisms.

Monitoring of physiological parameters from multiple patients using wireless sensor network.

PubMed

Yuce, Mehmet R; Ng, Peng Choong; Khan, Jamil Y

2008-10-01

This paper presents a wireless sensor network system that has the capability to monitor physiological parameters from multiple patient bodies. The system uses the Medical Implant Communication Service band between the sensor nodes and a remote central control unit (CCU) that behaves as a base station. The CCU communicates with another network standard (the internet or a mobile network) for a long distance data transfer. The proposed system offers mobility to patients and flexibility to medical staff to obtain patient's physiological data on demand basis via Internet. A prototype sensor network including hardware, firmware and software designs has been implemented and tested. The developed system has been optimized for power consumption by having the nodes sleep when there is no communication via a bidirectional communication.

A Survey on FPGA-Based Sensor Systems: Towards Intelligent and Reconfigurable Low-Power Sensors for Computer Vision, Control and Signal Processing

PubMed Central

García, Gabriel J.; Jara, Carlos A.; Pomares, Jorge; Alabdo, Aiman; Poggi, Lucas M.; Torres, Fernando

2014-01-01

The current trend in the evolution of sensor systems seeks ways to provide more accuracy and resolution, while at the same time decreasing the size and power consumption. The use of Field Programmable Gate Arrays (FPGAs) provides specific reprogrammable hardware technology that can be properly exploited to obtain a reconfigurable sensor system. This adaptation capability enables the implementation of complex applications using the partial reconfigurability at a very low-power consumption. For highly demanding tasks FPGAs have been favored due to the high efficiency provided by their architectural flexibility (parallelism, on-chip memory, etc.), reconfigurability and superb performance in the development of algorithms. FPGAs have improved the performance of sensor systems and have triggered a clear increase in their use in new fields of application. A new generation of smarter, reconfigurable and lower power consumption sensors is being developed in Spain based on FPGAs. In this paper, a review of these developments is presented, describing as well the FPGA technologies employed by the different research groups and providing an overview of future research within this field. PMID:24691100

A survey on FPGA-based sensor systems: towards intelligent and reconfigurable low-power sensors for computer vision, control and signal processing.

PubMed

García, Gabriel J; Jara, Carlos A; Pomares, Jorge; Alabdo, Aiman; Poggi, Lucas M; Torres, Fernando

2014-03-31

The current trend in the evolution of sensor systems seeks ways to provide more accuracy and resolution, while at the same time decreasing the size and power consumption. The use of Field Programmable Gate Arrays (FPGAs) provides specific reprogrammable hardware technology that can be properly exploited to obtain a reconfigurable sensor system. This adaptation capability enables the implementation of complex applications using the partial reconfigurability at a very low-power consumption. For highly demanding tasks FPGAs have been favored due to the high efficiency provided by their architectural flexibility (parallelism, on-chip memory, etc.), reconfigurability and superb performance in the development of algorithms. FPGAs have improved the performance of sensor systems and have triggered a clear increase in their use in new fields of application. A new generation of smarter, reconfigurable and lower power consumption sensors is being developed in Spain based on FPGAs. In this paper, a review of these developments is presented, describing as well the FPGA technologies employed by the different research groups and providing an overview of future research within this field.

An Efficient Interactive Model for On-Demand Sensing-As-A-Servicesof Sensor-Cloud

PubMed Central

Dinh, Thanh; Kim, Younghan

2016-01-01

This paper proposes an efficient interactive model for the sensor-cloud to enable the sensor-cloud to efficiently provide on-demand sensing services for multiple applications with different requirements at the same time. The interactive model is designed for both the cloud and sensor nodes to optimize the resource consumption of physical sensors, as well as the bandwidth consumption of sensing traffic. In the model, the sensor-cloud plays a key role in aggregating application requests to minimize the workloads required for constrained physical nodes while guaranteeing that the requirements of all applications are satisfied. Physical sensor nodes perform their sensing under the guidance of the sensor-cloud. Based on the interactions with the sensor-cloud, physical sensor nodes adapt their scheduling accordingly to minimize their energy consumption. Comprehensive experimental results show that our proposed system achieves a significant improvement in terms of the energy consumption of physical sensors, the bandwidth consumption from the sink node to the sensor-cloud, the packet delivery latency, reliability and scalability, compared to current approaches. Based on the obtained results, we discuss the economical benefits and how the proposed system enables a win-win model in the sensor-cloud. PMID:27367689

An Efficient Interactive Model for On-Demand Sensing-As-A-Servicesof Sensor-Cloud.

PubMed

Dinh, Thanh; Kim, Younghan

2016-06-28

This paper proposes an efficient interactive model for the sensor-cloud to enable the sensor-cloud to efficiently provide on-demand sensing services for multiple applications with different requirements at the same time. The interactive model is designed for both the cloud and sensor nodes to optimize the resource consumption of physical sensors, as well as the bandwidth consumption of sensing traffic. In the model, the sensor-cloud plays a key role in aggregating application requests to minimize the workloads required for constrained physical nodes while guaranteeing that the requirements of all applications are satisfied. Physical sensor nodes perform their sensing under the guidance of the sensor-cloud. Based on the interactions with the sensor-cloud, physical sensor nodes adapt their scheduling accordingly to minimize their energy consumption. Comprehensive experimental results show that our proposed system achieves a significant improvement in terms of the energy consumption of physical sensors, the bandwidth consumption from the sink node to the sensor-cloud, the packet delivery latency, reliability and scalability, compared to current approaches. Based on the obtained results, we discuss the economical benefits and how the proposed system enables a win-win model in the sensor-cloud.

Large space structures control algorithm characterization

NASA Technical Reports Server (NTRS)

Fogel, E.

1983-01-01

Feedback control algorithms are developed for sensor/actuator pairs on large space systems. These algorithms have been sized in terms of (1) floating point operation (FLOP) demands; (2) storage for variables; and (3) input/output data flow. FLOP sizing (per control cycle) was done as a function of the number of control states and the number of sensor/actuator pairs. Storage for variables and I/O sizing was done for specific structure examples.

Development, implementation, and characterization of a standalone embedded viscosity measurement system based on the impedance spectroscopy of a vibrating wire sensor

NASA Astrophysics Data System (ADS)

Santos, José; Janeiro, Fernando M.; Ramos, Pedro M.

2015-10-01

This paper presents an embedded liquid viscosity measurement system based on a vibrating wire sensor. Although multiple viscometers based on different working principles are commercially available, there is still a market demand for a dedicated measurement system capable of performing accurate, fast measurements and requiring little or no operator training for simple systems and solution monitoring. The developed embedded system is based on a vibrating wire sensor that works by measuring the impedance response of the sensor, which depends on the viscosity and density of the liquid in which the sensor is immersed. The core of the embedded system is a digital signal processor (DSP) which controls the waveform generation and acquisitions for the measurement of the impedance frequency response. The DSP also processes the acquired waveforms and estimates the liquid viscosity. The user can interact with the measurement system through a keypad and an LCD or through a computer with a USB connection for data logging and processing. The presented system is tested on a set of viscosity standards and the estimated values are compared with the standard manufacturer specified viscosity values. A stability study of the measurement system is also performed.

A wireless medical monitoring over a heterogeneous sensor network.

PubMed

Yuce, Mehmet R; Ng, Peng Choong; Lee, Chin K; Khan, Jamil Y; Liu, Wentai

2007-01-01

This paper presents a heterogeneous sensor network system that has the capability to monitor physiological parameters from multiple patient bodies by means of different communication standards. The system uses the recently opened medical band called MICS (Medical Implant Communication Service) between the sensor nodes and a remote central control unit (CCU) that behaves as a base station. The CCU communicates with another network standard (the internet or a mobile network) for a long distance data transfer. The proposed system offers mobility to patients and flexibility to medical staff to obtain patient's physiological data on demand basis via Internet. A prototype sensor network including hardware, firmware and software designs has been implemented and tested by incorporating temperature and pulse rate sensors on nodes. The developed system has been optimized for power consumption by having the nodes sleep when there is no communication via a bidirectional communication.

Key Residential Building Equipment Technologies for Control and Grid Support PART I (Residential)

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

Starke, Michael R; Onar, Omer C; DeVault, Robert C

2011-09-01

Electrical energy consumption of the residential sector is a crucial area of research that has in the past primarily focused on increasing the efficiency of household devices such as water heaters, dishwashers, air conditioners, and clothes washer and dryer units. However, the focus of this research is shifting as objectives such as developing the smart grid and ensuring that the power system remains reliable come to the fore, along with the increasing need to reduce energy use and costs. Load research has started to focus on mechanisms to support the power system through demand reduction and/or reliability services. The powermore » system relies on matching generation and load, and day-ahead and real-time energy markets capture most of this need. However, a separate set of grid services exist to address the discrepancies in load and generation arising from contingencies and operational mismatches, and to ensure that the transmission system is available for delivery of power from generation to load. Currently, these grid services are mostly provided by generation resources. The addition of renewable resources with their inherent variability can complicate the issue of power system reliability and lead to the increased need for grid services. Using load as a resource, through demand response programs, can fill the additional need for flexible resources and even reduce costly energy peaks. Loads have been shown to have response that is equal to or better than generation in some cases. Furthermore, price-incentivized demand response programs have been shown to reduce the peak energy requirements, thereby affecting the wholesale market efficiency and overall energy prices. The residential sector is not only the largest consumer of electrical energy in the United States, but also has the highest potential to provide demand reduction and power system support, as technological advancements in load control, sensor technologies, and communication are made. The prevailing loads based on the largest electrical energy consumers in the residential sector are space heating and cooling, washer and dryer, water heating, lighting, computers and electronics, dishwasher and range, and refrigeration. As the largest loads, these loads provide the highest potential for delivering demand response and reliability services. Many residential loads have inherent flexibility that is related to the purpose of the load. Depending on the load type, electric power consumption levels can either be ramped, changed in a step-change fashion, or completely removed. Loads with only on-off capability (such as clothes washers and dryers) provide less flexibility than resources that can be ramped or step-changed. Add-on devices may be able to provide extra demand response capabilities. Still, operating residential loads effectively requires awareness of the delicate balance of occupants health and comfort and electrical energy consumption. This report is Phase I of a series of reports aimed at identifying gaps in automated home energy management systems for incorporation of building appliances, vehicles, and renewable adoption into a smart grid, specifically with the intent of examining demand response and load factor control for power system support. The objective is to capture existing gaps in load control, energy management systems, and sensor technology with consideration of PHEV and renewable technologies to establish areas of research for the Department of Energy. In this report, (1) data is collected and examined from state of the art homes to characterize the primary residential loads as well as PHEVs and photovoltaic for potential adoption into energy management control strategies; and (2) demand response rules and requirements across the various demand response programs are examined for potential participation of residential loads. This report will be followed by a Phase II report aimed at identifying the current state of technology of energy management systems, sensors, and communication technologies for demand response and load factor control applications for the residential sector. The purpose is to cover the gaps that exist in the information captured by the sensors for energy management system to be able to provide demand response and load factor control. The vision is the development of an energy management system or other controlling enterprise hardware and software that is not only able to control loads, PHEVs, and renewable generation for demand response and load factor control, but also to do so with consumer comforts in mind and in an optimal fashion.« less

Improving the efficiency of dissolved oxygen control using an on-line control system based on a genetic algorithm evolving FWNN software sensor.

PubMed

Ruan, Jujun; Zhang, Chao; Li, Ya; Li, Peiyi; Yang, Zaizhi; Chen, Xiaohong; Huang, Mingzhi; Zhang, Tao

2017-02-01

This work proposes an on-line hybrid intelligent control system based on a genetic algorithm (GA) evolving fuzzy wavelet neural network software sensor to control dissolved oxygen (DO) in an anaerobic/anoxic/oxic process for treating papermaking wastewater. With the self-learning and memory abilities of neural network, handling the uncertainty capacity of fuzzy logic, analyzing local detail superiority of wavelet transform and global search of GA, this proposed control system can extract the dynamic behavior and complex interrelationships between various operation variables. The results indicate that the reasonable forecasting and control performances were achieved with optimal DO, and the effluent quality was stable at and below the desired values in real time. Our proposed hybrid approach proved to be a robust and effective DO control tool, attaining not only adequate effluent quality but also minimizing the demand for energy, and is easily integrated into a global monitoring system for purposes of cost management. Copyright © 2016 Elsevier Ltd. All rights reserved.

Theory research of seam recognition and welding torch pose control based on machine vision

NASA Astrophysics Data System (ADS)

Long, Qiang; Zhai, Peng; Liu, Miao; He, Kai; Wang, Chunyang

2017-03-01

At present, the automation requirement of the welding become higher, so a method of the welding information extraction by vision sensor is proposed in this paper, and the simulation with the MATLAB has been conducted. Besides, in order to improve the quality of robot automatic welding, an information retrieval method for welding torch pose control by visual sensor is attempted. Considering the demands of welding technology and engineering habits, the relative coordinate systems and variables are strictly defined, and established the mathematical model of the welding pose, and verified its feasibility by using the MATLAB simulation in the paper, these works lay a foundation for the development of welding off-line programming system with high precision and quality.

The tip/tilt tracking sensor based on multi-anode photo-multiplier tube

NASA Astrophysics Data System (ADS)

Ma, Xiao-yu; Rao, Chang-hui; Tian, Yu; Wei, Kai

2013-09-01

Based on the demands of high sensitivity, precision and frame rate of tip/tilt tracking sensors in acquisition, tracking and pointing (ATP) systems for satellite-ground optical communications, this paper proposes to employ the multiple-anode photo-multiplier tubes (MAPMTs) in tip/tilt tracking sensors. Meanwhile, an array-type photon-counting system was designed to meet the requirements of the tip/tilt tracking sensors. The experiment results show that the tip/tilt tracking sensors based on MAPMTs can achieve photon sensitivity and high frame rate as well as low noise.

Cold-Rolled Strip Steel Stress Detection Technology Based on a Magnetoresistance Sensor and the Magnetoelastic Effect

PubMed Central

Guan, Ben; Zang, Yong; Han, Xiaohui; Zheng, Kailun

2018-01-01

Driven by the demands for contactless stress detection, technologies are being used for shape control when producing cold-rolled strips. This paper presents a novel contactless stress detection technology based on a magnetoresistance sensor and the magnetoelastic effect, enabling the detection of internal stress in manufactured cold-rolled strips. An experimental device was designed and produced. Characteristics of this detection technology were investigated through experiments assisted by theoretical analysis. Theoretically, a linear correlation exists between the internal stress of strip steel and the voltage output of a magneto-resistive sensor. Therefore, for this stress detection system, the sensitivity of the stress detection was adjusted by adjusting the supply voltage of the magnetoresistance sensor, detection distance, and other relevant parameters. The stress detection experimental results showed that this detection system has good repeatability and linearity. The detection error was controlled within 1.5%. Moreover, the intrinsic factors of the detected strip steel, including thickness, carbon percentage, and crystal orientation, also affected the sensitivity of the detection system. The detection technology proposed in this research enables online contactless detection and meets the requirements for cold-rolled steel strips. PMID:29883387

Cold-Rolled Strip Steel Stress Detection Technology Based on a Magnetoresistance Sensor and the Magnetoelastic Effect.

PubMed

Guan, Ben; Zang, Yong; Han, Xiaohui; Zheng, Kailun

2018-05-21

Driven by the demands for contactless stress detection, technologies are being used for shape control when producing cold-rolled strips. This paper presents a novel contactless stress detection technology based on a magnetoresistance sensor and the magnetoelastic effect, enabling the detection of internal stress in manufactured cold-rolled strips. An experimental device was designed and produced. Characteristics of this detection technology were investigated through experiments assisted by theoretical analysis. Theoretically, a linear correlation exists between the internal stress of strip steel and the voltage output of a magneto-resistive sensor. Therefore, for this stress detection system, the sensitivity of the stress detection was adjusted by adjusting the supply voltage of the magnetoresistance sensor, detection distance, and other relevant parameters. The stress detection experimental results showed that this detection system has good repeatability and linearity. The detection error was controlled within 1.5%. Moreover, the intrinsic factors of the detected strip steel, including thickness, carbon percentage, and crystal orientation, also affected the sensitivity of the detection system. The detection technology proposed in this research enables online contactless detection and meets the requirements for cold-rolled steel strips.

Latest developments for low-power infrared laser-based trace gas sensors for sensor networks

NASA Astrophysics Data System (ADS)

So, Stephen; Thomazy, David; Wang, Wen; Marchat, Oscar; Wysocki, Gerard

2011-09-01

Academic and industrial researchers require ultra-low power, compact laser based trace-gas sensor systems for the most demanding environmental and space-borne applications. Here the latest results from research projects addressing these applications will be discussed: 1) an ultra-compact CO2 sensor based on a continuous wave quantum cascade laser, 2) an ultra-sensitive Faraday rotation spectrometer for O2 detection, 3) a fully ruggedized compact and low-power laser spectrometer, and 4) a novel non-paraxial nonthin multipass cell. Preliminary tests and projection for performance of future sensors based on this technology is presented.

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

PubMed Central

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

2012-01-01

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

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

NASA Astrophysics Data System (ADS)

Klump, J. F.; Robertson, J.

2015-12-01

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

Research-grade CMOS image sensors for demanding space applications

NASA Astrophysics Data System (ADS)

Saint-Pé, Olivier; Tulet, Michel; Davancens, Robert; Larnaudie, Franck; Magnan, Pierre; Corbière, Franck; Martin-Gonthier, Philippe; Belliot, Pierre

2004-06-01

Imaging detectors are key elements for optical instruments and sensors on board space missions dedicated to Earth observation (high resolution imaging, atmosphere spectroscopy...), Solar System exploration (micro cameras, guidance for autonomous vehicle...) and Universe observation (space telescope focal planes, guiding sensors...). This market has been dominated by CCD technology for long. Since the mid-90s, CMOS Image Sensors (CIS) have been competing with CCDs for more and more consumer domains (webcams, cell phones, digital cameras...). Featuring significant advantages over CCD sensors for space applications (lower power consumption, smaller system size, better radiations behaviour...), CMOS technology is also expanding in this field, justifying specific R&D and development programs funded by national and European space agencies (mainly CNES, DGA, and ESA). All along the 90s and thanks to their increasingly improving performances, CIS have started to be successfully used for more and more demanding applications, from vision and control functions requiring low-level performances to guidance applications requiring medium-level performances. Recent technology improvements have made possible the manufacturing of research-grade CIS that are able to compete with CCDs in the high-performances arena. After an introduction outlining the growing interest of optical instruments designers for CMOS image sensors, this talk will present the existing and foreseen ways to reach high-level electro-optics performances for CIS. The developments of CIS prototypes built using an imaging CMOS process and of devices based on improved designs will be presented.

Research-grade CMOS image sensors for demanding space applications

NASA Astrophysics Data System (ADS)

Saint-Pé, Olivier; Tulet, Michel; Davancens, Robert; Larnaudie, Franck; Magnan, Pierre; Corbière, Franck; Martin-Gonthier, Philippe; Belliot, Pierre

2017-11-01

Imaging detectors are key elements for optical instruments and sensors on board space missions dedicated to Earth observation (high resolution imaging, atmosphere spectroscopy...), Solar System exploration (micro cameras, guidance for autonomous vehicle...) and Universe observation (space telescope focal planes, guiding sensors...). This market has been dominated by CCD technology for long. Since the mid- 90s, CMOS Image Sensors (CIS) have been competing with CCDs for more and more consumer domains (webcams, cell phones, digital cameras...). Featuring significant advantages over CCD sensors for space applications (lower power consumption, smaller system size, better radiations behaviour...), CMOS technology is also expanding in this field, justifying specific R&D and development programs funded by national and European space agencies (mainly CNES, DGA, and ESA). All along the 90s and thanks to their increasingly improving performances, CIS have started to be successfully used for more and more demanding applications, from vision and control functions requiring low-level performances to guidance applications requiring medium-level performances. Recent technology improvements have made possible the manufacturing of research-grade CIS that are able to compete with CCDs in the high-performances arena. After an introduction outlining the growing interest of optical instruments designers for CMOS image sensors, this talk will present the existing and foreseen ways to reach high-level electro-optics performances for CIS. The developments of CIS prototypes built using an imaging CMOS process and of devices based on improved designs will be presented.

Pollution source localization in an urban water supply network based on dynamic water demand.

PubMed

Yan, Xuesong; Zhu, Zhixin; Li, Tian

2017-10-27

Urban water supply networks are susceptible to intentional, accidental chemical, and biological pollution, which pose a threat to the health of consumers. In recent years, drinking-water pollution incidents have occurred frequently, seriously endangering social stability and security. The real-time monitoring for water quality can be effectively implemented by placing sensors in the water supply network. However, locating the source of pollution through the data detection obtained by water quality sensors is a challenging problem. The difficulty lies in the limited number of sensors, large number of water supply network nodes, and dynamic user demand for water, which leads the pollution source localization problem to an uncertainty, large-scale, and dynamic optimization problem. In this paper, we mainly study the dynamics of the pollution source localization problem. Previous studies of pollution source localization assume that hydraulic inputs (e.g., water demand of consumers) are known. However, because of the inherent variability of urban water demand, the problem is essentially a fluctuating dynamic problem of consumer's water demand. In this paper, the water demand is considered to be stochastic in nature and can be described using Gaussian model or autoregressive model. On this basis, an optimization algorithm is proposed based on these two dynamic water demand change models to locate the pollution source. The objective of the proposed algorithm is to find the locations and concentrations of pollution sources that meet the minimum between the analogue and detection values of the sensor. Simulation experiments were conducted using two different sizes of urban water supply network data, and the experimental results were compared with those of the standard genetic algorithm.

Homeostasis control of building environment using sensor agent robot

NASA Astrophysics Data System (ADS)

Nagahama, Eri; Mita, Akira

2012-04-01

A human centered system for building is demanded to meet variety of needs due to the diversification and maturation of society. Smart buildings and smart houses have been studied to satisfy this demand. However, it is difficult for such systems to respond flexibly to unexpected events and needs that are caused by aging and complicate emotion changes. With this regards, we suggest "Biofied Buildings". The goal for this research is to realize buildings that are safer, more comfortable and more energy-efficient by embedding adaptive functions of life into buildings. In this paper, we propose a new control system for building environments, focused on physiological adaptation, particularly homeostasis, endocrine system and immune system. Residents are used as living sensors and controllers in the control loop. A sensor agent robot is used to acquire resident's discomfort feeling, and to output hormone-like signals to activate devices to control the environments. The proposed system could control many devices without establishing complicated scenarios. Results obtained from some simulations and the demonstration experiments using an LED lighting system showed that the proposed system were able to achieve robust and stable control of environments without complicated scenarios.

A state observer for using a slow camera as a sensor for fast control applications

NASA Astrophysics Data System (ADS)

Gahleitner, Reinhard; Schagerl, Martin

2013-03-01

This contribution concerns about a problem that often arises in vision based control, when a camera is used as a sensor for fast control applications, or more precisely, when the sample rate of the control loop is higher than the frame rate of the camera. In control applications for mechanical axes, e.g. in robotics or automated production, a camera and some image processing can be used as a sensor to detect positions or angles. The sample time in these applications is typically in the range of a few milliseconds or less and this demands the use of a camera with a high frame rate up to 1000 fps. The presented solution is a special state observer that can work with a slower and therefore cheaper camera to estimate the state variables at the higher sample rate of the control loop. To simplify the image processing for the determination of positions or angles and make it more robust, some LED markers are applied to the plant. Simulation and experimental results show that the concept can be used even if the plant is unstable like the inverted pendulum.

Novel Hybrid Scheduling Technique for Sensor Nodes with Mixed Criticality Tasks.

PubMed

Micea, Mihai-Victor; Stangaciu, Cristina-Sorina; Stangaciu, Valentin; Curiac, Daniel-Ioan

2017-06-26

Sensor networks become increasingly a key technology for complex control applications. Their potential use in safety- and time-critical domains has raised the need for task scheduling mechanisms specially adapted to sensor node specific requirements, often materialized in predictable jitter-less execution of tasks characterized by different criticality levels. This paper offers an efficient scheduling solution, named Hybrid Hard Real-Time Scheduling (H²RTS), which combines a static, clock driven method with a dynamic, event driven scheduling technique, in order to provide high execution predictability, while keeping a high node Central Processing Unit (CPU) utilization factor. From the detailed, integrated schedulability analysis of the H²RTS, a set of sufficiency tests are introduced and demonstrated based on the processor demand and linear upper bound metrics. The performance and correct behavior of the proposed hybrid scheduling technique have been extensively evaluated and validated both on a simulator and on a sensor mote equipped with ARM7 microcontroller.

Open Source Platform Application to Groundwater Characterization and Monitoring

NASA Astrophysics Data System (ADS)

Ntarlagiannis, D.; Day-Lewis, F. D.; Falzone, S.; Lane, J. W., Jr.; Slater, L. D.; Robinson, J.; Hammett, S.

2017-12-01

Groundwater characterization and monitoring commonly rely on the use of multiple point sensors and human labor. Due to the number of sensors, labor, and other resources needed, establishing and maintaining an adequate groundwater monitoring network can be both labor intensive and expensive. To improve and optimize the monitoring network design, open source software and hardware components could potentially provide the platform to control robust and efficient sensors thereby reducing costs and labor. This work presents early attempts to create a groundwater monitoring system incorporating open-source software and hardware that will control the remote operation of multiple sensors along with data management and file transfer functions. The system is built around a Raspberry PI 3, that controls multiple sensors in order to perform on-demand, continuous or `smart decision' measurements while providing flexibility to incorporate additional sensors to meet the demands of different projects. The current objective of our technology is to monitor exchange of ionic tracers between mobile and immobile porosity using a combination of fluid and bulk electrical-conductivity measurements. To meet this objective, our configuration uses four sensors (pH, specific conductance, pressure, temperature) that can monitor the fluid electrical properties of interest and guide the bulk electrical measurement. This system highlights the potential of using open source software and hardware components for earth sciences applications. The versatility of the system makes it ideal for use in a large number of applications, and the low cost allows for high resolution (spatially and temporally) monitoring.

Performance evaluation and modeling of a conformal filter (CF) based real-time standoff hazardous material detection sensor

NASA Astrophysics Data System (ADS)

Nelson, Matthew P.; Tazik, Shawna K.; Bangalore, Arjun S.; Treado, Patrick J.; Klem, Ethan; Temple, Dorota

2017-05-01

Hyperspectral imaging (HSI) systems can provide detection and identification of a variety of targets in the presence of complex backgrounds. However, current generation sensors are typically large, costly to field, do not usually operate in real time and have limited sensitivity and specificity. Despite these shortcomings, HSI-based intelligence has proven to be a valuable tool, thus resulting in increased demand for this type of technology. By moving the next generation of HSI technology into a more adaptive configuration, and a smaller and more cost effective form factor, HSI technologies can help maintain a competitive advantage for the U.S. armed forces as well as local, state and federal law enforcement agencies. Operating near the physical limits of HSI system capability is often necessary and very challenging, but is often enabled by rigorous modeling of detection performance. Specific performance envelopes we consistently strive to improve include: operating under low signal to background conditions; at higher and higher frame rates; and under less than ideal motion control scenarios. An adaptable, low cost, low footprint, standoff sensor architecture we have been maturing includes the use of conformal liquid crystal tunable filters (LCTFs). These Conformal Filters (CFs) are electro-optically tunable, multivariate HSI spectrometers that, when combined with Dual Polarization (DP) optics, produce optimized spectral passbands on demand, which can readily be reconfigured, to discriminate targets from complex backgrounds in real-time. With DARPA support, ChemImage Sensor Systems (CISS™) in collaboration with Research Triangle Institute (RTI) International are developing a novel, real-time, adaptable, compressive sensing short-wave infrared (SWIR) hyperspectral imaging technology called the Reconfigurable Conformal Imaging Sensor (RCIS) based on DP-CF technology. RCIS will address many shortcomings of current generation systems and offer improvements in operational agility and detection performance, while addressing sensor weight, form factor and cost needs. This paper discusses recent test and performance modeling results of a RCIS breadboard apparatus.

An Accurate and Generic Testing Approach to Vehicle Stability Parameters Based on GPS and INS.

PubMed

Miao, Zhibin; Zhang, Hongtian; Zhang, Jinzhu

2015-12-04

With the development of the vehicle industry, controlling stability has become more and more important. Techniques of evaluating vehicle stability are in high demand. As a common method, usually GPS sensors and INS sensors are applied to measure vehicle stability parameters by fusing data from the two system sensors. Although prior model parameters should be recognized in a Kalman filter, it is usually used to fuse data from multi-sensors. In this paper, a robust, intelligent and precise method to the measurement of vehicle stability is proposed. First, a fuzzy interpolation method is proposed, along with a four-wheel vehicle dynamic model. Second, a two-stage Kalman filter, which fuses the data from GPS and INS, is established. Next, this approach is applied to a case study vehicle to measure yaw rate and sideslip angle. The results show the advantages of the approach. Finally, a simulation and real experiment is made to verify the advantages of this approach. The experimental results showed the merits of this method for measuring vehicle stability, and the approach can meet the design requirements of a vehicle stability controller.

A Study of a Handrim-Activated Power-Assist Wheelchair Based on a Non-Contact Torque Sensor

PubMed Central

Nam, Ki-Tae; Jang, Dae-Jin; Kim, Yong Chol; Heo, Yoon; Hong, Eung-Pyo

2016-01-01

Demand for wheelchairs is increasing with growing numbers of aged and disabled persons. Manual wheelchairs are the most commonly used assistive device for mobility because they are convenient to transport. Manual wheelchairs have several advantages but are not easy to use for the elderly or those who lack muscular strength. Therefore, handrim-activated power-assist wheelchairs (HAPAW) that can aid driving power with a motor by detecting user driving intentions through the handrim are being researched. This research will be on HAPAW that judge user driving intentions by using non-contact torque sensors. To deliver the desired motion, which is sensed from handrim rotation relative to a fixed controller, a new driving wheel mechanism is designed by applying a non-contact torque sensor, and corresponding torques are simulated. Torques are measured by a driving wheel prototype and compared with simulation results. The HAPAW prototype was developed using the wheels and a driving control algorithm that uses left and right input torques and time differences are used to check if the non-contact torque sensor can distinguish users’ driving intentions. Through this procedure, it was confirmed that the proposed sensor can be used effectively in HAPAW. PMID:27509508

An intelligent knowledge-based and customizable home care system framework with ubiquitous patient monitoring and alerting techniques.

PubMed

Chen, Yen-Lin; Chiang, Hsin-Han; Yu, Chao-Wei; Chiang, Chuan-Yen; Liu, Chuan-Ming; Wang, Jenq-Haur

2012-01-01

This study develops and integrates an efficient knowledge-based system and a component-based framework to design an intelligent and flexible home health care system. The proposed knowledge-based system integrates an efficient rule-based reasoning model and flexible knowledge rules for determining efficiently and rapidly the necessary physiological and medication treatment procedures based on software modules, video camera sensors, communication devices, and physiological sensor information. This knowledge-based system offers high flexibility for improving and extending the system further to meet the monitoring demands of new patient and caregiver health care by updating the knowledge rules in the inference mechanism. All of the proposed functional components in this study are reusable, configurable, and extensible for system developers. Based on the experimental results, the proposed intelligent homecare system demonstrates that it can accomplish the extensible, customizable, and configurable demands of the ubiquitous healthcare systems to meet the different demands of patients and caregivers under various rehabilitation and nursing conditions.

An Intelligent Knowledge-Based and Customizable Home Care System Framework with Ubiquitous Patient Monitoring and Alerting Techniques

PubMed Central

Chen, Yen-Lin; Chiang, Hsin-Han; Yu, Chao-Wei; Chiang, Chuan-Yen; Liu, Chuan-Ming; Wang, Jenq-Haur

2012-01-01

This study develops and integrates an efficient knowledge-based system and a component-based framework to design an intelligent and flexible home health care system. The proposed knowledge-based system integrates an efficient rule-based reasoning model and flexible knowledge rules for determining efficiently and rapidly the necessary physiological and medication treatment procedures based on software modules, video camera sensors, communication devices, and physiological sensor information. This knowledge-based system offers high flexibility for improving and extending the system further to meet the monitoring demands of new patient and caregiver health care by updating the knowledge rules in the inference mechanism. All of the proposed functional components in this study are reusable, configurable, and extensible for system developers. Based on the experimental results, the proposed intelligent homecare system demonstrates that it can accomplish the extensible, customizable, and configurable demands of the ubiquitous healthcare systems to meet the different demands of patients and caregivers under various rehabilitation and nursing conditions. PMID:23112650

Nanomaterial-enabled Rapid Detection of Water Contaminants.

PubMed

Mao, Shun; Chang, Jingbo; Zhou, Guihua; Chen, Junhong

2015-10-28

Water contaminants, e.g., inorganic chemicals and microorganisms, are critical metrics for water quality monitoring and have significant impacts on human health and plants/organisms living in water. The scope and focus of this review is nanomaterial-based optical, electronic, and electrochemical sensors for rapid detection of water contaminants, e.g., heavy metals, anions, and bacteria. These contaminants are commonly found in different water systems. The importance of water quality monitoring and control demands significant advancement in the detection of contaminants in water because current sensing technologies for water contaminants have limitations. The advantages of nanomaterial-based sensing technologies are highlighted and recent progress on nanomaterial-based sensors for rapid water contaminant detection is discussed. An outlook for future research into this rapidly growing field is also provided. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High Resolution Eddy-Current Wire Testing Based on a Gmr Sensor-Array

NASA Astrophysics Data System (ADS)

Kreutzbruck, Marc; Allweins, Kai; Strackbein, Chris; Bernau, Hendrick

2009-03-01

Increasing demands in materials quality and cost effectiveness have led to advanced standards in manufacturing technology. Especially when dealing with high quality standards in conjunction with high throughput quantitative NDE techniques are vital to provide reliable and fast quality control systems. In this work we illuminate a modern electromagnetic NDE approach using a small GMR sensor array for testing superconducting wires. Four GMR sensors are positioned around the wire. Each GMR sensor provides a field sensitivity of 200 pT/√Hz and a spatial resolution of about 100 μm. This enables us to detect under surface defects of 100 μm in size in a depth of 200 μm with a signal-to-noise ratio of better than 400. Surface defects could be detected with a SNR of up to 10,000. Besides this remarkably SNR the small extent of GMR sensors results in a spatial resolution which offers new visualisation techniques for defect localisation, defect characterization and tomography-like mapping techniques. We also report on inverse algorithms based on either a Finite Element Method or an analytical approach. These allow for accurate defect localization on the urn scale and an estimation of the defect size.

Design of a prototype position actuator for the primary mirror segments of the European Extremely Large Telescope

NASA Astrophysics Data System (ADS)

Jiménez, A.; Morante, E.; Viera, T.; Núñez, M.; Reyes, M.

2010-07-01

European Extremely Large Telescope (E-ELT) based in 984 primary mirror segments achieving required optical performance; they must position relatively to adjacent segments with relative nanometer accuracy. CESA designed M1 Position Actuators (PACT) to comply with demanding performance requirements of EELT. Three PACT are located under each segment controlling three out of the plane degrees of freedom (tip, tilt, piston). To achieve a high linear accuracy in long operational displacements, PACT uses two stages in series. First stage based on Voice Coil Actuator (VCA) to achieve high accuracies in very short travel ranges, while second stage based on Brushless DC Motor (BLDC) provides large stroke ranges and allows positioning the first stage closer to the demanded position. A BLDC motor is used achieving a continuous smoothly movement compared to sudden jumps of a stepper. A gear box attached to the motor allows a high reduction of power consumption and provides a great challenge for sizing. PACT space envelope was reduced by means of two flat springs fixed to VCA. Its main characteristic is a low linear axial stiffness. To achieve best performance for PACT, sensors have been included in both stages. A rotary encoder is included in BLDC stage to close position/velocity control loop. An incremental optical encoder measures PACT travel range with relative nanometer accuracy and used to close the position loop of the whole actuator movement. For this purpose, four different optical sensors with different gratings will be evaluated. Control strategy show different internal closed loops that work together to achieve required performance.

Mixed Traffic Information Collection System based on Pressure Sensor

NASA Astrophysics Data System (ADS)

Liao, Wenzhe; Liu, Mingsheng; Meng, Qingli

The traffic information collection is the base of Intelligent Traffic.At present, there exist mixed traffic situation in urban road in China. This paper researched and implemented a system through collecting the vehicle and bicycle mixed traffic flow parameters based on pressure sensor. According to information collection requirements, we selected pressure sensor, designed the data collection, storage and other hardware circuitries and information processing software. The experiment shows that the system can meet the demand of traffic information collection in the actual.

QUEST: Eliminating Online Supervised Learning for Efficient Classification Algorithms.

PubMed

Zwartjes, Ardjan; Havinga, Paul J M; Smit, Gerard J M; Hurink, Johann L

2016-10-01

In this work, we introduce QUEST (QUantile Estimation after Supervised Training), an adaptive classification algorithm for Wireless Sensor Networks (WSNs) that eliminates the necessity for online supervised learning. Online processing is important for many sensor network applications. Transmitting raw sensor data puts high demands on the battery, reducing network life time. By merely transmitting partial results or classifications based on the sampled data, the amount of traffic on the network can be significantly reduced. Such classifications can be made by learning based algorithms using sampled data. An important issue, however, is the training phase of these learning based algorithms. Training a deployed sensor network requires a lot of communication and an impractical amount of human involvement. QUEST is a hybrid algorithm that combines supervised learning in a controlled environment with unsupervised learning on the location of deployment. Using the SITEX02 dataset, we demonstrate that the presented solution works with a performance penalty of less than 10% in 90% of the tests. Under some circumstances, it even outperforms a network of classifiers completely trained with supervised learning. As a result, the need for on-site supervised learning and communication for training is completely eliminated by our solution.

STTR Phase I: Low-Cost, High-Accuracy, Whole-Building Carbon Dioxide Monitoring for Demand Control Ventilation

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

Hallstrom, Jason O.; Ni, Zheng Richard

This STTR Phase I project assessed the feasibility of a new CO 2 sensing system optimized for low-cost, high-accuracy, whole-building monitoring for use in demand control ventilation. The focus was on the development of a wireless networking platform and associated firmware to provide signal conditioning and conversion, fault- and disruptiontolerant networking, and multi-hop routing at building scales to avoid wiring costs. Early exploration of a bridge (or “gateway”) to direct digital control services was also explored. Results of the project contributed to an improved understanding of a new electrochemical sensor for monitoring indoor CO 2 concentrations, as well as themore » electronics and networking infrastructure required to deploy those sensors at building scales. New knowledge was acquired concerning the sensor’s accuracy, environmental response, and failure modes, and the acquisition electronics required to achieve accuracy over a wide range of CO 2 concentrations. The project demonstrated that the new sensor offers repeatable correspondence with commercial optical sensors, with supporting electronics that offer gain accuracy within 0.5%, and acquisition accuracy within 1.5% across three orders of magnitude variation in generated current. Considering production, installation, and maintenance costs, the technology presents a foundation for achieving whole-building CO 2 sensing at a price point below $0.066 / sq-ft – meeting economic feasibility criteria established by the Department of Energy. The technology developed under this award addresses obstacles on the critical path to enabling whole-building CO 2 sensing and demand control ventilation in commercial retrofits, small commercial buildings, residential complexes, and other highpotential structures that have been slow to adopt these technologies. It presents an opportunity to significantly reduce energy use throughout the United States.« less

Strain Sensors with Adjustable Sensitivity by Tailoring the Microstructure of Graphene Aerogel/PDMS Nanocomposites.

PubMed

Wu, Shuying; Ladani, Raj B; Zhang, Jin; Ghorbani, Kamran; Zhang, Xuehua; Mouritz, Adrian P; Kinloch, Anthony J; Wang, Chun H

2016-09-21

Strain sensors with high elastic limit and high sensitivity are required to meet the rising demand for wearable electronics. Here, we present the fabrication of highly sensitive strain sensors based on nanocomposites consisting of graphene aerogel (GA) and polydimethylsiloxane (PDMS), with the primary focus being to tune the sensitivity of the sensors by tailoring the cellular microstructure through controlling the manufacturing processes. The resultant nanocomposite sensors exhibit a high sensitivity with a gauge factor of up to approximately 61.3. Of significant importance is that the sensitivity of the strain sensors can be readily altered by changing the concentration of the precursor (i.e., an aqueous dispersion of graphene oxide) and the freezing temperature used to process the GA. The results reveal that these two parameters control the cell size and cell-wall thickness of the resultant GA, which may be correlated to the observed variations in the sensitivities of the strain sensors. The higher is the concentration of graphene oxide, then the lower is the sensitivity of the resultant nanocomposite strain sensor. Upon increasing the freezing temperature from -196 to -20 °C, the sensitivity increases and reaches a maximum value of 61.3 at -50 °C and then decreases with a further increase in freezing temperature to -20 °C. Furthermore, the strain sensors offer excellent durability and stability, with their piezoresistivities remaining virtually unchanged even after 10 000 cycles of high-strain loading-unloading. These novel findings pave the way to custom design strain sensors with a desirable piezoresistive behavior.

Effects of the contamination environment on surfaces and materials

NASA Technical Reports Server (NTRS)

Maag, Carl R.

1989-01-01

In addition to the issues that have always existed, demands are being placed on space systems for increased contamination prevention/control. Optical surveillance sensors are required to detect low radiance targets. This increases the need for very low scatter surfaces in the optical system. Particulate contamination levels typically experienced in today's working environments/habits will most likely compromise these sensors. Contamination (molecular and particulate) can also affect the survivability of space sensors in both the natural and hostile space environments. The effects of di-octyl phthalate (DOP) on sensors are discussed.

An Accurate and Generic Testing Approach to Vehicle Stability Parameters Based on GPS and INS

PubMed Central

Miao, Zhibin; Zhang, Hongtian; Zhang, Jinzhu

2015-01-01

With the development of the vehicle industry, controlling stability has become more and more important. Techniques of evaluating vehicle stability are in high demand. As a common method, usually GPS sensors and INS sensors are applied to measure vehicle stability parameters by fusing data from the two system sensors. Although prior model parameters should be recognized in a Kalman filter, it is usually used to fuse data from multi-sensors. In this paper, a robust, intelligent and precise method to the measurement of vehicle stability is proposed. First, a fuzzy interpolation method is proposed, along with a four-wheel vehicle dynamic model. Second, a two-stage Kalman filter, which fuses the data from GPS and INS, is established. Next, this approach is applied to a case study vehicle to measure yaw rate and sideslip angle. The results show the advantages of the approach. Finally, a simulation and real experiment is made to verify the advantages of this approach. The experimental results showed the merits of this method for measuring vehicle stability, and the approach can meet the design requirements of a vehicle stability controller. PMID:26690154

Novel Hybrid Scheduling Technique for Sensor Nodes with Mixed Criticality Tasks

PubMed Central

Micea, Mihai-Victor; Stangaciu, Cristina-Sorina; Stangaciu, Valentin; Curiac, Daniel-Ioan

2017-01-01

Sensor networks become increasingly a key technology for complex control applications. Their potential use in safety- and time-critical domains has raised the need for task scheduling mechanisms specially adapted to sensor node specific requirements, often materialized in predictable jitter-less execution of tasks characterized by different criticality levels. This paper offers an efficient scheduling solution, named Hybrid Hard Real-Time Scheduling (H2RTS), which combines a static, clock driven method with a dynamic, event driven scheduling technique, in order to provide high execution predictability, while keeping a high node Central Processing Unit (CPU) utilization factor. From the detailed, integrated schedulability analysis of the H2RTS, a set of sufficiency tests are introduced and demonstrated based on the processor demand and linear upper bound metrics. The performance and correct behavior of the proposed hybrid scheduling technique have been extensively evaluated and validated both on a simulator and on a sensor mote equipped with ARM7 microcontroller. PMID:28672856

Algorithms for in-season nutrient management in cereals

USDA-ARS?s Scientific Manuscript database

The demand for improved decision making products for cereal production systems has placed added emphasis on using plant sensors in-season, and that incorporate real-time, site specific, growing environments. The objective of this work was to describe validated in-season sensor based algorithms prese...

A Novel Thermal Sensor for the Sensitive Measurement of Chemical Oxygen Demand

PubMed Central

Yao, Na; Liu, Zhuan; Chen, Ying; Zhou, Yikai; Xie, Bin

2015-01-01

A novel rapid methodology for determining the chemical oxygen demand (COD) based on a thermal sensor with a flow injection analysis system was proposed and experimentally validated. The ability of this sensor to detect and monitor COD was based on the degree of enthalpy increase when sodium hypochlorite reacted with the organic content in water samples. The measurement results were correlated with COD and were compared against the conventional method using potassium dichromate. The assay required only 5–7 min rather than the 2 h required for evaluation by potassium dichromate. The linear range was 5–1000 mg/L COD, and the limit of detection was very low, 0.74 mg/L COD. Moreover, this method exhibited high tolerance to chloride ions; 0.015 mol/L chloride ions had no influence on the response. Finally, the sensor was used to detect the COD of different water samples; the results were verified by the standard dichromate method. PMID:26295397

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

PubMed Central

Costa, Daniel G.; Guedes, Luiz Affonso

2010-01-01

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

CMOS based capacitance to digital converter circuit for MEMS sensor

NASA Astrophysics Data System (ADS)

Rotake, D. R.; Darji, A. D.

2018-02-01

Most of the MEMS cantilever based system required costly instruments for characterization, processing and also has large experimental setups which led to non-portable device. So there is a need of low cost, highly sensitive, high speed and portable digital system. The proposed Capacitance to Digital Converter (CDC) interfacing circuit converts capacitance to digital domain which can be easily processed. Recent demand microcantilever deflection is part per trillion ranges which change the capacitance in 1-10 femto farad (fF) range. The entire CDC circuit is designed using CMOS 250nm technology. Design of CDC circuit consists of a D-latch and two oscillators, namely Sensor controlled oscillator (SCO) and digitally controlled oscillator (DCO). The D-latch is designed using transmission gate based MUX for power optimization. A CDC design of 7-stage, 9-stage and 11-stage tested for 1-18 fF and simulated using mentor graphics Eldo tool with parasitic. Since the proposed design does not use resistance component, the total power dissipation is reduced to 2.3621 mW for CDC designed using 9-stage SCO and DCO.

Highly sensitive and selective detection of Al(III) ions in aqueous buffered solution with fluorescent peptide-based sensor.

PubMed

In, Byunggyu; Hwang, Gi Won; Lee, Keun-Hyeung

2016-09-15

A fluorescent sensor based on a tripeptide (SerGluGlu) with a dansyl fluorophore detected selectively Al(III) among 16 metal ions in aqueous buffered solutions without any organic cosolvent. The peptide-based sensor showed a highly sensitive turn on response to aluminium ion with high binding affinity (1.84×10(4)M(-1)) in aqueous buffered solutions. The detection limit (230nM, 5.98ppb) of the peptide-based sensor was much lower than the maximum allowable level (7.41μM) of aluminium ions in drinking water demanded by EPA. The binding mode of the peptide sensor with aluminium ions was characterized using ESI mass spectrometry, NMR titration, and pH titration experiments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Power monitoring and control for large scale projects: SKA, a case study

NASA Astrophysics Data System (ADS)

Barbosa, Domingos; Barraca, João. Paulo; Maia, Dalmiro; Carvalho, Bruno; Vieira, Jorge; Swart, Paul; Le Roux, Gerhard; Natarajan, Swaminathan; van Ardenne, Arnold; Seca, Luis

2016-07-01

Large sensor-based science infrastructures for radio astronomy like the SKA will be among the most intensive datadriven projects in the world, facing very high demanding computation, storage, management, and above all power demands. The geographically wide distribution of the SKA and its associated processing requirements in the form of tailored High Performance Computing (HPC) facilities, require a Greener approach towards the Information and Communications Technologies (ICT) adopted for the data processing to enable operational compliance to potentially strict power budgets. Addressing the reduction of electricity costs, improve system power monitoring and the generation and management of electricity at system level is paramount to avoid future inefficiencies and higher costs and enable fulfillments of Key Science Cases. Here we outline major characteristics and innovation approaches to address power efficiency and long-term power sustainability for radio astronomy projects, focusing on Green ICT for science and Smart power monitoring and control.

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.

Human-centered sensor-based Bayesian control: Increased energy efficiency and user satisfaction in commercial lighting

NASA Astrophysics Data System (ADS)

Granderson, Jessica Ann

2007-12-01

The need for sustainable, efficient energy systems is the motivation that drove this research, which targeted the design of an intelligent commercial lighting system. Lighting in commercial buildings consumes approximately 13% of all the electricity generated in the US. Advanced lighting controls1 intended for use in commercial office spaces have proven to save up to 45% in electricity consumption. However, they currently comprise only a fraction of the market share, resulting in a missed opportunity to conserve energy. The research goals driving this dissertation relate directly to barriers hindering widespread adoption---increase user satisfaction, and provide increased energy savings through more sophisticated control. To satisfy these goals an influence diagram was developed to perform daylighting actuation. This algorithm was designed to balance the potentially conflicting lighting preferences of building occupants, with the efficiency desires of building facilities management. A supervisory control policy was designed to implement load shedding under a demand response tariff. Such tariffs offer incentives for customers to reduce their consumption during periods of peak demand, trough price reductions. In developing the value function occupant user testing was conducted to determine that computer and paper tasks require different illuminance levels, and that user preferences are sufficiently consistent to attain statistical significance. Approximately ten facilities managers were also interviewed and surveyed to isolate their lighting preferences with respect to measures of lighting quality and energy savings. Results from both simulation and physical implementation and user testing indicate that the intelligent controller can increase occupant satisfaction, efficiency, cost savings, and management satisfaction, with respect to existing commercial daylighting systems. Several important contributions were realized by satisfying the research goals. A general model of a daylighted environment was designed, and a practical means of user preference identification was defined. Further, a set of general procedures were identified for the design of human-centered sensor-based decision-analytic systems, and for the identification of the allowable uncertainty in nodes of interest. To confirm generality, a vehicle health monitoring problem was defined and solved using these two procedures. 1'Daylighting' systems use sensors to determine room occupancy and available sunlight, and automatically dim the lights in response.

A novel and lightweight system to secure wireless medical sensor networks.

PubMed

He, Daojing; Chan, Sammy; Tang, Shaohua

2014-01-01

Wireless medical sensor networks (MSNs) are a key enabling technology in e-healthcare that allows the data of a patient's vital body parameters to be collected by the wearable or implantable biosensors. However, the security and privacy protection of the collected data is a major unsolved issue, with challenges coming from the stringent resource constraints of MSN devices, and the high demand for both security/privacy and practicality. In this paper, we propose a lightweight and secure system for MSNs. The system employs hash-chain based key updating mechanism and proxy-protected signature technique to achieve efficient secure transmission and fine-grained data access control. Furthermore, we extend the system to provide backward secrecy and privacy preservation. Our system only requires symmetric-key encryption/decryption and hash operations and is thus suitable for the low-power sensor nodes. This paper also reports the experimental results of the proposed system in a network of resource-limited motes and laptop PCs, which show its efficiency in practice. To the best of our knowledge, this is the first secure data transmission and access control system for MSNs until now.

Accuracy of different sensors for the estimation of pollutant concentrations (total suspended solids, total and dissolved chemical oxygen demand) in wastewater and stormwater.

PubMed

Lepot, Mathieu; Aubin, Jean-Baptiste; Bertrand-Krajewski, Jean-Luc

2013-01-01

Many field investigations have used continuous sensors (turbidimeters and/or ultraviolet (UV)-visible spectrophotometers) to estimate with a short time step pollutant concentrations in sewer systems. Few, if any, publications compare the performance of various sensors for the same set of samples. Different surrogate sensors (turbidity sensors, UV-visible spectrophotometer, pH meter, conductivity meter and microwave sensor) were tested to link concentrations of total suspended solids (TSS), total and dissolved chemical oxygen demand (COD), and sensors' outputs. In the combined sewer at the inlet of a wastewater treatment plant, 94 samples were collected during dry weather, 44 samples were collected during wet weather, and 165 samples were collected under both dry and wet weather conditions. From these samples, triplicate standard laboratory analyses were performed and corresponding sensors outputs were recorded. Two outlier detection methods were developed, based, respectively, on the Mahalanobis and Euclidean distances. Several hundred regression models were tested, and the best ones (according to the root mean square error criterion) are presented in order of decreasing performance. No sensor appears as the best one for all three investigated pollutants.

Dynamic control of nutrient-removal from industrial wastewater in a sequencing batch reactor, using common and low-cost online sensors.

PubMed

Dries, Jan

2016-01-01

On-line control of the biological treatment process is an innovative tool to cope with variable concentrations of chemical oxygen demand and nutrients in industrial wastewater. In the present study we implemented a simple dynamic control strategy for nutrient-removal in a sequencing batch reactor (SBR) treating variable tank truck cleaning wastewater. The control system was based on derived signals from two low-cost and robust sensors that are very common in activated sludge plants, i.e. oxidation reduction potential (ORP) and dissolved oxygen. The amount of wastewater fed during anoxic filling phases, and the number of filling phases in the SBR cycle, were determined by the appearance of the 'nitrate knee' in the profile of the ORP. The phase length of the subsequent aerobic phases was controlled by the oxygen uptake rate measured online in the reactor. As a result, the sludge loading rate (F/M ratio), the volume exchange rate and the SBR cycle length adapted dynamically to the activity of the activated sludge and the actual characteristics of the wastewater, without affecting the final effluent quality.

Smart monolithic integration of inkjet printed thermal flow sensors with fast prototyping polymer microfluidics

NASA Astrophysics Data System (ADS)

Etxebarria, Ikerne; Elizalde, Jorge; Pacios, Roberto

2016-08-01

There is an increasing demand for built-in flow sensors in order to effectively control microfluidic processes due to the high number of available microfluidic applications. The possible solutions should be inexpensive and easy to connect to both, the microscale features and the macro setup. In this paper, we present a novel approach to integrate a printed thermal flow sensor with polymeric microfluidic channels. This approach is focused on merging two high throughput production processes, namely inkjet printing and fast prototyping technologies, in order to produce trustworthy and low cost devices. These two technologies are brought together to obtain a sensor located outside the microfluidic device. This avoids the critical contact between the sensor material and the fluids through the microchannels that can seriously damage the conducting paths under continuous working regimes. In this way, we ensure reliable and stable operation modes. For this application, a silver nanoparticle based ink and cyclic olefin polymer were used. This flow sensor operates linearly in the range of 0-10 μl min-1 for water and 0-20 μl min-1 for ethanol in calorimetric mode. Switching to anemometric mode, the range can be expanded up to 40 μl min-1.

Design of smart neonatal health monitoring system using SMCC

PubMed Central

Mukherjee, Anwesha; Bhakta, Ishita

2016-01-01

Automated health monitoring and alert system development is a demanding research area today. Most of the currently available monitoring and controlling medical devices are wired which limits freeness of working environment. Wireless sensor network (WSN) is a better alternative in such an environment. Neonatal intensive care unit is used to take care of sick and premature neonates. Hypothermia is an independent risk factor for neonatal mortality and morbidity. To prevent it an automated monitoring system is required. In this Letter, an automated neonatal health monitoring system is designed using sensor mobile cloud computing (SMCC). SMCC is based on WSN and MCC. In the authors’ system temperature sensor, acceleration sensor and heart rate measurement sensor are used to monitor body temperature, acceleration due to body movement and heart rate of neonates. The sensor data are stored inside the cloud. The health person continuously monitors and accesses these data through the mobile device using an Android Application for neonatal monitoring. When an abnormal situation arises, an alert is generated in the mobile device of the health person. By alerting health professional using such an automated system, early care is provided to the affected babies and the probability of recovery is increased. PMID:28261491

Design of smart neonatal health monitoring system using SMCC.

PubMed

De, Debashis; Mukherjee, Anwesha; Sau, Arkaprabha; Bhakta, Ishita

2017-02-01

Automated health monitoring and alert system development is a demanding research area today. Most of the currently available monitoring and controlling medical devices are wired which limits freeness of working environment. Wireless sensor network (WSN) is a better alternative in such an environment. Neonatal intensive care unit is used to take care of sick and premature neonates. Hypothermia is an independent risk factor for neonatal mortality and morbidity. To prevent it an automated monitoring system is required. In this Letter, an automated neonatal health monitoring system is designed using sensor mobile cloud computing (SMCC). SMCC is based on WSN and MCC. In the authors' system temperature sensor, acceleration sensor and heart rate measurement sensor are used to monitor body temperature, acceleration due to body movement and heart rate of neonates. The sensor data are stored inside the cloud. The health person continuously monitors and accesses these data through the mobile device using an Android Application for neonatal monitoring. When an abnormal situation arises, an alert is generated in the mobile device of the health person. By alerting health professional using such an automated system, early care is provided to the affected babies and the probability of recovery is increased.

Microbial BOD sensors based on Zr (IV)-loaded collagen fiber.

PubMed

Zhao, Lei; He, Li; Chen, Shujuan; Zou, Likou; Zhou, Kang; Ao, Xiaolin; Liu, Shuliang; Hu, Xinjie; Han, Guoquan

2017-03-01

Biochemical oxygen demand (BOD) sensors based on Zr (IV)-loaded collagen fiber (ZrCF), a novel material with great porous structure, were developed. This novel material shows adsorbability by microorganisms. Saccharomyces cerevisiae and Escherichia coli were used for the construction of BOD sensors. Factors affecting BOD sensor performance were examined. The ZrCF-based BOD sensor showed different sensitivities and linear response ranges with different biofilm densities. The amount of microorganisms strongly affected the performance of the BOD sensor. Poor permeability of previously reported immobilization carriers were greatly circumvented by ZrCF. The service life of the ZrCF-based BOD sensor was more than 42 days. The immobilized microorganisms can be stored for more than 6 months under 4°C in PB solution. There was good correlation between the results of the sensor method and the standard 5-day BOD method in the determination of pure organic substrates and real water samples. Copyright © 2016 Elsevier Inc. All rights reserved.

A novel solution for car traffic control based on radiometric microwave devices

NASA Astrophysics Data System (ADS)

Soldovieri, Francesco; Denisov, Alexander; Speziale, Victor

2014-05-01

The significant problem of traffic in big cities, connected with huge and building up quantity of automobile cars, demands for novel strategies, based on nonconventional solutions, in order to improve system traffic control, especially at crossroads. As well known, the usual solution is based on the time relay, which requires the installation of a fixed traffic interval (signal light switching) at a crossroad; this solution is low cost, but does not account for the actual traffic conditions. Therefore, in the recent years, attention is towards to new designs, where the monitoring of the and control of traffic is carried out by using various methods including, optical, the infrared, magnetic, radar tracking, acoustical ones. In this work, we discuss the deployment of high sensitivity radiometric systems and radiometers(sensor) in the microwave range [1, 2]. In fact, the radiometer as "sensor" can provide an always updated information about the car traffic in any weather condition and in absence or low visibility conditions. In fact, the radiometric sensor detects the cars thanks to the different behavior of the car roofs which reflect the cold sky whereas the road asphalt is visible as warm object (at around outside temperature). [1] A. G. Denisov, V. P. Gorishnyak, S. E. Kuzmin et al., "Some experiments concerning resolution of 32 sensors passive 8mm wave imaging system," in Proceedings of the International Symposium on Space Terahertz Technology (ISSTT '09), Charlottesville, Va, USA, April 2009. [2] F. Soldovieri, A. Natale, V. Gorishnyak, A. Pavluchenko, A. Denisov, and L. Chen, "Radiometric Imaging for Monitoring and Surveillance Issues," International Journal of Antennas and Propagation, vol. 2013, Article ID 272561, 8 pages, 2013. doi:10.1155/2013/272561.

Microneedle pH Sensor: Direct, Label-Free, Real-Time Detection of Cerebrospinal Fluid and Bladder pH.

PubMed

Mani, Ganesh Kumar; Miyakoda, Kousei; Saito, Asuka; Yasoda, Yutaka; Kajiwara, Kagemasa; Kimura, Minoru; Tsuchiya, Kazuyoshi

2017-07-05

Acid-base homeostasis (body pH) inside the body is precisely controlled by the kidneys and lungs and buffer systems, such that even a minor pH change could severely affect many organs. Blood and urine pH tests are common in day-to-day clinical trials and require little effort for diagnosis. There is always a great demand for in vivo testing to understand more about body metabolism and to provide effective diagnosis and therapy. In this article, we report the simple fabrication of microneedle-based direct, label-free, and real-time pH sensors. The reference and working electrodes were Ag/AgCl thick films and ZnO thin films on tungsten (W) microneedles, respectively. The morphological and structural characteristics of microneedles were carefully investigated through various analytical methods. The developed sensor exhibited a Nernstian response of -46 mV/pH. Different conditions were used to test the sensor to confirm their accuracy and stability, such as various buffer solutions, with respect to time, and we compared the reading with commercial pH electrodes. Besides that, the fabricated microneedle sensor ability is proven by in vivo testing in mouse cerebrospinal fluid (CSF) and bladders. The pH sensor procedure reported here is totally reversible, and results were reproducible after several rounds of testing.

Integrated dynamic and static tactile sensor: focus on static force sensing

NASA Astrophysics Data System (ADS)

Wettels, Nicholas; Pletner, Baruch

2012-04-01

Object grasping by robotic hands in unstructured environments demands a sensor that is durable, compliant, and responsive to static and dynamic force conditions. In order for a tactile sensor to be useful for grasp control in these, it should have the following properties: tri-axial force sensing (two shear plus normal component), dynamic event sensing across slip frequencies, compliant surface for grip, wide dynamic range (depending on application), insensitivity to environmental conditions, ability to withstand abuse and good sensing behavior (e.g. low hysteresis, high repeatability). These features can be combined in a novel multimodal tactile sensor. This sensor combines commercial-off-the-shelf MEMS technology with two proprietary force sensors: a high bandwidth device based on PZT technology and low bandwidth device based on elastomers and optics. In this study, we focus on the latter transduction mechanism and the proposed architecture of the completed device. In this study, an embedded LED was utilized to produce a constant light source throughout a layer of silicon rubber which covered a plastic mandrel containing a set of sensitive phototransistors. Features about the contacted object such as center of pressure and force vectors can be extracted from the information in the changing patterns of light. The voltage versus force relationship obtained with this molded humanlike finger had a wide dynamic range that coincided with forces relevant for most human grip tasks.

FPGA-Based Smart Sensor for Online Displacement Measurements Using a Heterodyne Interferometer

PubMed Central

Vera-Salas, Luis Alberto; Moreno-Tapia, Sandra Veronica; Garcia-Perez, Arturo; de Jesus Romero-Troncoso, Rene; Osornio-Rios, Roque Alfredo; Serroukh, Ibrahim; Cabal-Yepez, Eduardo

2011-01-01

The measurement of small displacements on the nanometric scale demands metrological systems of high accuracy and precision. In this context, interferometer-based displacement measurements have become the main tools used for traceable dimensional metrology. The different industrial applications in which small displacement measurements are employed requires the use of online measurements, high speed processes, open architecture control systems, as well as good adaptability to specific process conditions. The main contribution of this work is the development of a smart sensor for large displacement measurement based on phase measurement which achieves high accuracy and resolution, designed to be used with a commercial heterodyne interferometer. The system is based on a low-cost Field Programmable Gate Array (FPGA) allowing the integration of several functions in a single portable device. This system is optimal for high speed applications where online measurement is needed and the reconfigurability feature allows the addition of different modules for error compensation, as might be required by a specific application. PMID:22164040

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

USGS Publications Warehouse

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

2008-01-01

In response to NASA's announced requirement for Earth hazard monitoring sensor-web technology, a multidisciplinary team involving sensor-network experts (Washington State University), space scientists (JPL), and Earth scientists (USGS Cascade Volcano Observatory (CVO)), is developing a prototype dynamic and scaleable hazard monitoring sensor-web and applying it to volcano monitoring. The combined Optimized Autonomous Space -In-situ Sensor-web (OASIS) will have two-way communication capability between ground and space assets, use both space and ground data for optimal allocation of limited power and bandwidth resources on the ground, and use smart management of competing demands for limited space assets. It will also enable scalability and seamless infusion of future space and in-situ assets into the sensor-web. The prototype will be focused on volcano hazard monitoring at Mount St. Helens, which has been active since October 2004. The system is designed to be flexible and easily configurable for many other applications as well. The primary goals of the project are: 1) integrating complementary space (i.e., Earth Observing One (EO-1) satellite) and in-situ (ground-based) elements into an interactive, autonomous sensor-web; 2) advancing sensor-web power and communication resource management technology; and 3) enabling scalability for seamless infusion of future space and in-situ assets into the sensor-web. To meet these goals, we are developing: 1) a test-bed in-situ array with smart sensor nodes capable of making autonomous data acquisition decisions; 2) efficient self-organization algorithm of sensor-web topology to support efficient data communication and command control; 3) smart bandwidth allocation algorithms in which sensor nodes autonomously determine packet priorities based on mission needs and local bandwidth information in real-time; and 4) remote network management and reprogramming tools. The space and in-situ control components of the system will be integrated such that each element is capable of autonomously tasking the other. Sensor-web data acquisition and dissemination will be accomplished through the use of the Open Geospatial Consortium Sensorweb Enablement protocols. The three-year project will demonstrate end-to-end system performance with the in-situ test-bed at Mount St. Helens and NASA's EO-1 platform. ??2008 IEEE.

Low-cost and disposable pressure sensor mat for non-invasive sleep and movement monitoring applications.

PubMed

Abraham, Jose K; Sullivan, Shawn; Ranganathan, Sridhar

2011-01-01

Sleep has profound effects on the physical and mental well-being of an individual. The National Institutes of Health (NIH) Sleep Disorder Research Plan gives particular emphasis to non-invasive sleep monitoring methods. Older adults experience sleep fragmentation due to sleep disorders. Unobtrusive non-contact monitoring can be the only realistic solution for long term home-based sleep monitoring. The demand for a low-cost and non-invasive sleep monitoring system for in-home use is more than before due to an increasingly stressful life style. Cost and complexity of current sensor elements hinder the development of low-cost sleep monitoring devices for in-home use. This paper presents the design, development and implementation of a low-cost and disposable pressure sensor mat that could be useful for in-home sleep and movement monitoring applications. The sensor mat design is based on a compressible foam sandwiched between two orthogonal arrays of cPaper capacitance sensors. A low-cost conducting paper has been developed for use as the capacitance sensor electrode. Typical mat design uses a 3 mm thick foam with 5 mm row/column grid array shows that it has a measurement resolution of 0.1 PSI pressure. The resolution can be controlled by both modifying properties of the conducting paper and the foam. Since this pressure mat design is based on low-cost paper, the sensor electrodes are disposable or semi-durable and hence it is ideal for the use in point-of-care physiological monitoring, pervasive healthcare and consumer electronic devices.

Integration of piezo-capacitive and piezo-electric nanoweb based pressure sensors for imaging of static and dynamic pressure distribution.

PubMed

Jeong, Y J; Oh, T I; Woo, E J; Kim, K J

2017-07-01

Recently, highly flexible and soft pressure distribution imaging sensor is in great demand for tactile sensing, gait analysis, ubiquitous life-care based on activity recognition, and therapeutics. In this study, we integrate the piezo-capacitive and piezo-electric nanowebs with the conductive fabric sheets for detecting static and dynamic pressure distributions on a large sensing area. Electrical impedance tomography (EIT) and electric source imaging are applied for reconstructing pressure distribution images from measured current-voltage data on the boundary of the hybrid fabric sensor. We evaluated the piezo-capacitive nanoweb sensor, piezo-electric nanoweb sensor, and hybrid fabric sensor. The results show the feasibility of static and dynamic pressure distribution imaging from the boundary measurements of the fabric sensors.

Self-deployable mobile sensor networks for on-demand surveillance

NASA Astrophysics Data System (ADS)

Miao, Lidan; Qi, Hairong; Wang, Feiyi

2005-05-01

This paper studies two interconnected problems in mobile sensor network deployment, the optimal placement of heterogeneous mobile sensor platforms for cost-efficient and reliable coverage purposes, and the self-organizable deployment. We first develop an optimal placement algorithm based on a "mosaicked technology" such that different types of mobile sensors form a mosaicked pattern uniquely determined by the popularity of different types of sensor nodes. The initial state is assumed to be random. In order to converge to the optimal state, we investigate the swarm intelligence (SI)-based sensor movement strategy, through which the randomly deployed sensors can self-organize themselves to reach the optimal placement state. The proposed algorithm is compared with the random movement and the centralized method using performance metrics such as network coverage, convergence time, and energy consumption. Simulation results are presented to demonstrate the effectiveness of the mosaic placement and the SI-based movement.

Optical sensor array platform based on polymer electronic devices

NASA Astrophysics Data System (ADS)

Koetse, Marc M.; Rensing, Peter A.; Sharpe, Ruben B. A.; van Heck, Gert T.; Allard, Bart A. M.; Meulendijks, Nicole N. M. M.; Kruijt, Peter G. M.; Tijdink, Marcel W. W. J.; De Zwart, René M.; Houben, René J.; Enting, Erik; van Veen, Sjaak J. J. F.; Schoo, Herman F. M.

2007-10-01

Monitoring of personal wellbeing and optimizing human performance are areas where sensors have only begun to be used. One of the reasons for this is the specific demands that these application areas put on the underlying technology and system properties. In many cases these sensors will be integrated in clothing, be worn on the skin, or may even be placed inside the body. This implies that flexibility and wearability of the systems is essential for their success. Devices based on polymer semiconductors allow for these demands since they can be fabricated with thin film technology. The use of thin film device technology allows for the fabrication of very thin sensors (e.g. integrated in food product packaging), flexible or bendable sensors in wearables, large area/distributed sensors, and intrinsically low-cost applications in disposable products. With thin film device technology a high level of integration can be achieved with parts that analyze signals, process and store data, and interact over a network. Integration of all these functions will inherently lead to better cost/performance ratios, especially if printing and other standard polymer technology such as high precision moulding is applied for the fabrication. In this paper we present an optical transmission sensor array based on polymer semiconductor devices made by thin film technology. The organic devices, light emitting diodes, photodiodes and selective medium chip, are integrated with classic electronic components. Together they form a versatile sensor platform that allows for the quantitative measurement of 100 channels and communicates wireless with a computer. The emphasis is given to the sensor principle, the design, fabrication technology and integration of the thin film devices.

TAS::89 0927::TAS RECOVERY - The Lean Green Energy Controller Machine

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

Teeter, John; Wang, Gene; Moss, David

Achieving efficiency improvements and providing demand-response programs have been identified as key elements of our national energy initiative. The residential market is the largest, yet most difficult, segment to engage in efforts to meet these objectives. This project developed Energy Management System that engages the consumer and enables Smart Grid services, applications, and business processes to address this need. Our innovative solution provides smart controller providing dynamic optimization of energy consumption for the residential energy consumer. Our solution extends the technical platform to include a cloud based Internet of Things (IoT) aggregation of data sensors and actuators the go beyondmore » energy management and extend to life style services provided through compelling mobile and console based user experiences.« less

RFID sensor-tags feeding a context-aware rule-based healthcare monitoring system.

PubMed

Catarinucci, Luca; Colella, Riccardo; Esposito, Alessandra; Tarricone, Luciano; Zappatore, Marco

2012-12-01

Along with the growing of the aging population and the necessity of efficient wellness systems, there is a mounting demand for new technological solutions able to support remote and proactive healthcare. An answer to this need could be provided by the joint use of the emerging Radio Frequency Identification (RFID) technologies and advanced software choices. This paper presents a proposal for a context-aware infrastructure for ubiquitous and pervasive monitoring of heterogeneous healthcare-related scenarios, fed by RFID-based wireless sensors nodes. The software framework is based on a general purpose architecture exploiting three key implementation choices: ontology representation, multi-agent paradigm and rule-based logic. From the hardware point of view, the sensing and gathering of context-data is demanded to a new Enhanced RFID Sensor-Tag. This new device, de facto, makes possible the easy integration between RFID and generic sensors, guaranteeing flexibility and preserving the benefits in terms of simplicity of use and low cost of UHF RFID technology. The system is very efficient and versatile and its customization to new scenarios requires a very reduced effort, substantially limited to the update/extension of the ontology codification. Its effectiveness is demonstrated by reporting both customization effort and performance results obtained from validation in two different healthcare monitoring contexts.

Wake-up transceivers for structural health monitoring of bridges

NASA Astrophysics Data System (ADS)

Kumberg, T.; Kokert, J.; Younesi, V.; Koenig, S.; Reindl, L. M.

2016-04-01

In this article we present a wireless sensor network to monitor the structural health of a large-scale highway bridge in Germany. The wireless sensor network consists of several sensor nodes that use wake-up receivers to realize latency free and low-power communication. The sensor nodes are either equipped with very accurate tilt sensor developed by Northrop Grumman LITEF GmbH or with a Novatel OEM615 GNSS receiver. Relay nodes are required to forward measurement data to a base station located on the bridge. The base station is a gateway that transmits the local measurement data to a remote server where it can be further analyzed and processed. Further on, we present an energy harvesting system to supply the energy demanding GNSS sensor nodes to realize long term monitoring.

Design details of Intelligent Instruments for PLC-free Cryogenic measurements, control and data acquisition

NASA Astrophysics Data System (ADS)

Antony, Joby; Mathuria, D. S.; Chaudhary, Anup; Datta, T. S.; Maity, T.

2017-02-01

Cryogenic network for linear accelerator operations demand a large number of Cryogenic sensors, associated instruments and other control-instrumentation to measure, monitor and control different cryogenic parameters remotely. Here we describe an alternate approach of six types of newly designed integrated intelligent cryogenic instruments called device-servers which has the complete circuitry for various sensor-front-end analog instrumentation and the common digital back-end http-server built together, to make crateless PLC-free model of controls and data acquisition. These identified instruments each sensor-specific viz. LHe server, LN2 Server, Control output server, Pressure server, Vacuum server and Temperature server are completely deployed over LAN for the cryogenic operations of IUAC linac (Inter University Accelerator Centre linear Accelerator), New Delhi. This indigenous design gives certain salient features like global connectivity, low cost due to crateless model, easy signal processing due to integrated design, less cabling and device-interconnectivity etc.

Cyber-physical system for a water reclamation plant: Balancing aeration, energy, and water quality to maintain process resilience

NASA Astrophysics Data System (ADS)

Zhu, Junjie

Aeration accounts for a large fraction of energy consumption in conventional water reclamation plants (WRPs). Although process operations at older WRPs can satisfy effluent permit requirements, they typically operate with excess aeration. More effective process controls at older WRPs can be challenging as operators work to balance higher energy costs and more stringent effluent limitations while managing fluctuating loads. Therefore, understandings of process resilience or ability to quickly return to original operation conditions at a WRP are important. A state-of-art WRP should maintain process resilience to deal with different kinds of perturbations even after optimization of energy demands. This work was to evaluate the applicability and feasibility of cyber-physical system (CPS) for improving operation at Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) Calumet WRP. In this work, a process model was developed and used to better understand the conditions of current Calumet WRP, with additional valuable information from two dissolved oxygen field measurements. Meanwhile, a classification system was developed to reveal the pattern of historical influent scenario based on cluster analysis and cross-tabulation analysis. Based on the results from the classification, typical process control options were investigated. To ensure the feasibility of information acquisition, the reliability and flexibility of soft sensors were assessed to typical influent conditions. Finally, the process resilience was investigated to better balance influent perturbations, energy demands, and effluent quality for long-term operations. These investigations and evaluations show that although the energy demands change as the influent conditions and process controls. In general, aeration savings could be up to 50% from the level of current consumption; with a more complex process controls, the saving could be up to 70% in relatively steady-state conditions and at least 40% in relatively challenging transient conditions. The soft sensors can provide reliable and flexible performance on target predictions. The plant can still maintain at a similar level of process resilience after 50% aeration saving, even during long-term perturbations. Overall, this work shows that it is well feasible to provide more cost-effective operations at the Calumet WRP, and meanwhile influent perturbations, effluent quality, and process resilience are well in balance.

Robust Operation of Tendon-Driven Robot Fingers Using Force and Position-Based Control Laws

NASA Technical Reports Server (NTRS)

Hargrave, Brian (Inventor); Abdallah, Muhammad E (Inventor); Reiland, Matthew J (Inventor); Diftler, Myron A (Inventor); Strawser, Philip A (Inventor); Platt, Jr., Robert J. (Inventor); Ihrke, Chris A. (Inventor)

2013-01-01

A robotic system includes a tendon-driven finger and a control system. The system controls the finger via a force-based control law when a tension sensor is available, and via a position-based control law when a sensor is not available. Multiple tendons may each have a corresponding sensor. The system selectively injects a compliance value into the position-based control law when only some sensors are available. A control system includes a host machine and a non-transitory computer-readable medium having a control process, which is executed by the host machine to control the finger via the force- or position-based control law. A method for controlling the finger includes determining the availability of a tension sensor(s), and selectively controlling the finger, using the control system, via the force or position-based control law. The position control law allows the control system to resist disturbances while nominally maintaining the initial state of internal tendon tensions.

Bio-inspired sensing and control for disturbance rejection and stabilization

NASA Astrophysics Data System (ADS)

Gremillion, Gregory; Humbert, James S.

2015-05-01

The successful operation of small unmanned aircraft systems (sUAS) in dynamic environments demands robust stability in the presence of exogenous disturbances. Flying insects are sensor-rich platforms, with highly redundant arrays of sensors distributed across the insect body that are integrated to extract rich information with diminished noise. This work presents a novel sensing framework in which measurements from an array of accelerometers distributed across a simulated flight vehicle are linearly combined to directly estimate the applied forces and torques with improvements in SNR. In simulation, the estimation performance is quantified as a function of sensor noise level, position estimate error, and sensor quantity.

A market-based optimization approach to sensor and resource management

NASA Astrophysics Data System (ADS)

Schrage, Dan; Farnham, Christopher; Gonsalves, Paul G.

2006-05-01

Dynamic resource allocation for sensor management is a problem that demands solutions beyond traditional approaches to optimization. Market-based optimization applies solutions from economic theory, particularly game theory, to the resource allocation problem by creating an artificial market for sensor information and computational resources. Intelligent agents are the buyers and sellers in this market, and they represent all the elements of the sensor network, from sensors to sensor platforms to computational resources. These agents interact based on a negotiation mechanism that determines their bidding strategies. This negotiation mechanism and the agents' bidding strategies are based on game theory, and they are designed so that the aggregate result of the multi-agent negotiation process is a market in competitive equilibrium, which guarantees an optimal allocation of resources throughout the sensor network. This paper makes two contributions to the field of market-based optimization: First, we develop a market protocol to handle heterogeneous goods in a dynamic setting. Second, we develop arbitrage agents to improve the efficiency in the market in light of its dynamic nature.

Greenhouse irrigation control system design based on ZigBee and fuzzy PID technology

NASA Astrophysics Data System (ADS)

Zhou, Bing; Yang, Qiliang; Liu, Kenan; Li, Peiqing; Zhang, Jing; Wang, Qijian

In order to achieve the water demand information accurately detect of the greenhouse crop and its precision irrigation automatic control, this article has designed a set of the irrigated control system based on ZigBee and fuzzy PID technology, which composed by the soil water potential sensor, CC2530F256 wireless microprocessor, IAR Embedded Workbench software development platform. And the time of Irrigation as the output .while the amount of soil water potential and crop growth cycle as the input. The article depended on Greenhouse-grown Jatropha to verify the object, the results show that the system can irrigate timely and appropriately according to the soil water potential and water demend of the different stages of Jatropha growth , which basically meet the design requirements. Therefore, the system has broad application prospects in the amount of greenhouse crop of fine control irrigation.

Towards practical implementation of biophotonics-based solutions for cost-effective monitoring of food quality control (Conference Presentation)

NASA Astrophysics Data System (ADS)

Meglinski, Igor; Popov, Alexey; Bykov, Alexander

2017-03-01

Biophotonics-based diagnostic and imaging modalities have been widely used in various applications associated with the non-invasive imaging of the internal structure of a range biological media from a range of cells cultures to biological tissues. With the fast growing interest in food securities there remains strong demand to apply reliable and cost effective biophotonics-based technologies for rapid screening of freshness, internal defects and quality of major agricultural products. In current presentation the results of application of optical coherence tomography (OCT) and encapsulated optical bio-sensors for quantitative assessment of freshness of agricultural products, such as meat and sea foods, are presented, and their further perspectives are discussed.

Energy Efficiency Technology Demonstration Project for Florida Educational Facilities: Occupancy Sensors.

ERIC Educational Resources Information Center

Floyd, David B.; Parker, Danny S.; McIlvaine, Janet E. R.; Sherwin, John R.

A Florida study replaced conventional light switches with passive infrared or ultrasonic sensing systems to control classroom lighting in an elementary school to determine the performance of such controls in saving energy. A before-and-after monitoring protocol was used for 33 classrooms and 7 offices in which electrical demand data were…

Virtual sensor models for real-time applications

NASA Astrophysics Data System (ADS)

Hirsenkorn, Nils; Hanke, Timo; Rauch, Andreas; Dehlink, Bernhard; Rasshofer, Ralph; Biebl, Erwin

2016-09-01

Increased complexity and severity of future driver assistance systems demand extensive testing and validation. As supplement to road tests, driving simulations offer various benefits. For driver assistance functions the perception of the sensors is crucial. Therefore, sensors also have to be modeled. In this contribution, a statistical data-driven sensor-model, is described. The state-space based method is capable of modeling various types behavior. In this contribution, the modeling of the position estimation of an automotive radar system, including autocorrelations, is presented. For rendering real-time capability, an efficient implementation is presented.

A suite of optical fibre sensors for structural condition monitoring

NASA Astrophysics Data System (ADS)

Sun, T.; Grattan, K. T. V.; Carlton, J.

2015-05-01

This paper is to review the research activities at City University London in the development of a range of fibre Bragg grating (FBG)-based sensors, including strain, temperature, relative humidity, vibration and acoustic sensors, with an aim to meet the increasing demands from industry for structural condition monitoring. As a result, arrays of optical fibre sensors have been instrumented into various types of structures, including concrete, limestone, marine propellers, pantograph and electrical motors, allowing for both static and dynamic monitoring and thus enhanced structural reliability and integrity.

Using Sensor Web Processes and Protocols to Assimilate Satellite Data into a Forecast Model

NASA Technical Reports Server (NTRS)

Goodman, H. Michael; Conover, Helen; Zavodsky, Bradley; Maskey, Manil; Jedlovec, Gary; Regner, Kathryn; Li, Xiang; Lu, Jessica; Botts, Mike; Berthiau, Gregoire

2008-01-01

The goal of the Sensor Management Applied Research Technologies (SMART) On-Demand Modeling project is to develop and demonstrate the readiness of the Open Geospatial Consortium (OGC) Sensor Web Enablement (SWE) capabilities to integrate both space-based Earth observations and forecast model output into new data acquisition and assimilation strategies. The project is developing sensor web-enabled processing plans to assimilate Atmospheric Infrared Sounding (AIRS) satellite temperature and moisture retrievals into a regional Weather Research and Forecast (WRF) model over the southeastern United States.

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.

Laser beam welding quality monitoring system based in high-speed (10 kHz) uncooled MWIR imaging sensors

NASA Astrophysics Data System (ADS)

Linares, Rodrigo; Vergara, German; Gutiérrez, Raúl; Fernández, Carlos; Villamayor, Víctor; Gómez, Luis; González-Camino, Maria; Baldasano, Arturo; Castro, G.; Arias, R.; Lapido, Y.; Rodríguez, J.; Romero, Pablo

2015-05-01

The combination of flexibility, productivity, precision and zero-defect manufacturing in future laser-based equipment are a major challenge that faces this enabling technology. New sensors for online monitoring and real-time control of laserbased processes are necessary for improving products quality and increasing manufacture yields. New approaches to fully automate processes towards zero-defect manufacturing demand smarter heads where lasers, optics, actuators, sensors and electronics will be integrated in a unique compact and affordable device. Many defects arising in laser-based manufacturing processes come from instabilities in the dynamics of the laser process. Temperature and heat dynamics are key parameters to be monitored. Low cost infrared imagers with high-speed of response will constitute the next generation of sensors to be implemented in future monitoring and control systems for laser-based processes, capable to provide simultaneous information about heat dynamics and spatial distribution. This work describes the result of using an innovative low-cost high-speed infrared imager based on the first quantum infrared imager monolithically integrated with Si-CMOS ROIC of the market. The sensor is able to provide low resolution images at frame rates up to 10 KHz in uncooled operation at the same cost as traditional infrared spot detectors. In order to demonstrate the capabilities of the new sensor technology, a low-cost camera was assembled on a standard production laser welding head, allowing to register melting pool images at frame rates of 10 kHz. In addition, a specific software was developed for defect detection and classification. Multiple laser welding processes were recorded with the aim to study the performance of the system and its application to the real-time monitoring of laser welding processes. During the experiments, different types of defects were produced and monitored. The classifier was fed with the experimental images obtained. Self-learning strategies were implemented with very promising results, demonstrating the feasibility of using low-cost high-speed infrared imagers in advancing towards a real-time / in-line zero-defect production systems.

Low-cost fabrication of highly sensitive room temperature hydrogen sensor based on ordered mesoporous Co-doped TiO2 structure

NASA Astrophysics Data System (ADS)

Li, Zhong; Haidry, Azhar Ali; Wang, Tao; Yao, Zheng Jun

2017-07-01

The development of cost-effective gas sensors with improved sensing properties and minimum power consumption for room temperature hydrogen leakage monitoring is in increasing demand. In this context, this report focus on the facile fabrication of ordered mesoporous TiO2 via evaporation-induced self-assembly route. With the controlled doping threshold (3%Co-TiO2), the output resistance change to 1000 ppm H2 is ˜4.1 × 103 with the response time of 66 s. The sensor response exhibits power law dependence with an increase in the hydrogen concentration, where the power law coefficient was found not only specific to the kind of target gas but also related to temperature. Further, the effect of structure integrity with doping level and humidity on sensing characteristics is interpreted in terms of variation in surface potential eVS and depletion region w caused by the adsorption of molecular oxygen O2-.

Application of an e-tongue to the analysis of monovarietal and blends of white wines.

PubMed

Gutiérrez, Manuel; Llobera, Andreu; Ipatov, Andrey; Vila-Planas, Jordi; Mínguez, Santiago; Demming, Stefanie; Büttgenbach, Stephanus; Capdevila, Fina; Domingo, Carme; Jiménez-Jorquera, Cecilia

2011-01-01

This work presents a multiparametric system capable of characterizing and classifying white wines according to the grape variety and geographical origin. Besides, it quantifies specific parameters of interest for quality control in wine. The system, known as a hybrid electronic tongue, consists of an array of electrochemical microsensors-six ISFET based sensors, a conductivity sensor, a redox potential sensor and two amperometric electrodes, a gold microelectrode and a microelectrode for sensing electrochemical oxygen demand--and a miniaturized optofluidic system. The test sample set comprised eighteen Catalan monovarietal white wines from four different grape varieties, two Croatian monovarietal white wines and seven bi- and trivarietal mixtures prepared from the Catalan varieties. Different chemometric tools were used to characterize (i.e., Principal Component Analysis), classify (i.e., Soft Independent Modeling Class Analogy) and quantify (i.e., Partial-Least Squares) some parameters of interest. The results demonstrate the usefulness of the multisensor system for analysis of wine.

Enhanced Bank of Kalman Filters Developed and Demonstrated for In-Flight Aircraft Engine Sensor Fault Diagnostics

NASA Technical Reports Server (NTRS)

Kobayashi, Takahisa; Simon, Donald L.

2005-01-01

In-flight sensor fault detection and isolation (FDI) is critical to maintaining reliable engine operation during flight. The aircraft engine control system, which computes control commands on the basis of sensor measurements, operates the propulsion systems at the demanded conditions. Any undetected sensor faults, therefore, may cause the control system to drive the engine into an undesirable operating condition. It is critical to detect and isolate failed sensors as soon as possible so that such scenarios can be avoided. A challenging issue in developing reliable sensor FDI systems is to make them robust to changes in engine operating characteristics due to degradation with usage and other faults that can occur during flight. A sensor FDI system that cannot appropriately account for such scenarios may result in false alarms, missed detections, or misclassifications when such faults do occur. To address this issue, an enhanced bank of Kalman filters was developed, and its performance and robustness were demonstrated in a simulation environment. The bank of filters is composed of m + 1 Kalman filters, where m is the number of sensors being used by the control system and, thus, in need of monitoring. Each Kalman filter is designed on the basis of a unique fault hypothesis so that it will be able to maintain its performance if a particular fault scenario, hypothesized by that particular filter, takes place.

Piezoresistive Sensor with High Elasticity Based on 3D Hybrid Network of Sponge@CNTs@Ag NPs.

PubMed

Zhang, Hui; Liu, Nishuang; Shi, Yuling; Liu, Weijie; Yue, Yang; Wang, Siliang; Ma, Yanan; Wen, Li; Li, Luying; Long, Fei; Zou, Zhengguang; Gao, Yihua

2016-08-31

Pressure sensors with high elasticity are in great demand for the realization of intelligent sensing, but there is a need to develope a simple, inexpensive, and scalable method for the manufacture of the sensors. Here, we reported an efficient, simple, facile, and repeatable "dipping and coating" process to manufacture a piezoresistive sensor with high elasticity, based on homogeneous 3D hybrid network of carbon nanotubes@silver nanoparticles (CNTs@Ag NPs) anchored on a skeleton sponge. Highly elastic, sensitive, and wearable sensors are obtained using the porous structure of sponge and the synergy effect of CNTs/Ag NPs. Our sensor was also tested for over 2000 compression-release cycles, exhibiting excellent elasticity and cycling stability. Sensors with high performance and a simple fabrication process are promising devices for commercial production in various electronic devices, for example, sport performance monitoring and man-machine interfaces.

Small Unmanned Aircraft Systems (SUAS) Flight Plan: 2016-2036. Bridging the Gap Between Tactical and Strategic

DTIC Science & Technology

2016-04-30

Certification. Simulators must be designed to keep pace with changes to SUAS and sensors. As new sensors, aircraft, and control stations are fielded ...insatiable demand continues to drive requirements that greatly out- pace capacity and budgets. To reverse these trends within the context of fiscal...levels requiring Federal Aviation Administration (FAA) mandated training requirements to integrate with manned air vehicles in the National Airspace

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

Auslander, David; Culler, David; Wright, Paul

The goal of the 2.5 year Distributed Intelligent Automated Demand Response (DIADR) project was to reduce peak electricity load of Sutardja Dai Hall at UC Berkeley by 30% while maintaining a healthy, comfortable, and productive environment for the occupants. We sought to bring together both central and distributed control to provide “deep” demand response1 at the appliance level of the building as well as typical lighting and HVAC applications. This project brought together Siemens Corporate Research and Siemens Building Technology (the building has a Siemens Apogee Building Automation System (BAS)), Lawrence Berkeley National Laboratory (leveraging their Open Automated Demand Responsemore » (openADR), Auto-­Demand Response, and building modeling expertise), and UC Berkeley (related demand response research including distributed wireless control, and grid-­to-­building gateway development). Sutardja Dai Hall houses the Center for Information Technology Research in the Interest of Society (CITRIS), which fosters collaboration among industry and faculty and students of four UC campuses (Berkeley, Davis, Merced, and Santa Cruz). The 141,000 square foot building, occupied in 2009, includes typical office spaces and a nanofabrication laboratory. Heating is provided by a district heating system (steam from campus as a byproduct of the campus cogeneration plant); cooling is provided by one of two chillers: a more typical electric centrifugal compressor chiller designed for the cool months (Nov-­ March) and a steam absorption chiller for use in the warm months (April-­October). Lighting in the open office areas is provided by direct-­indirect luminaries with Building Management System-­based scheduling for open areas, and occupancy sensors for private office areas. For the purposes of this project, we focused on the office portion of the building. Annual energy consumption is approximately 8053 MWh; the office portion is estimated as 1924 MWh. The maximum peak load during the study period was 1175 kW. Several new tools facilitated this work, such as the Smart Energy Box, the distributed load controller or Energy Information Gateway, the web-­based DR controller (dubbed the Central Load-­Shed Coordinator or CLSC), and the Demand Response Capacity Assessment & Operation Assistance Tool (DRCAOT). In addition, an innovative data aggregator called sMAP (simple Measurement and Actuation Profile) allowed data from different sources collected in a compact form and facilitated detailed analysis of the building systems operation. A smart phone application (RAP or Rapid Audit Protocol) facilitated an inventory of the building’s plug loads. Carbon dioxide sensors located in conference rooms and classrooms allowed demand controlled ventilation. The extensive submetering and nimble access to this data provided great insight into the details of the building operation as well as quick diagnostics and analyses of tests. For example, students discovered a short-­cycling chiller, a stuck damper, and a leaking cooling coil in the first field tests. For our final field tests, we were able to see how each zone was affected by the DR strategies (e.g., the offices on the 7th floor grew very warm quickly) and fine-­tune the strategies accordingly.« less

Adapting Wireless Technology to Lighting Control and Environmental Sensing

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

Dana Teasdale; Francis Rubinstein; Dave Watson

The high cost of retrofitting buildings with advanced lighting control systems is a barrier to adoption of this energy-saving technology. Wireless technology, however, offers a solution to mounting installation costs since it requires no additional wiring to implement. To demonstrate the feasibility of such a system, a prototype wirelessly-controlled advanced lighting system was designed and built. The system includes the following components: a wirelessly-controllable analog circuit module (ACM), a wirelessly-controllable electronic dimmable ballast, a T8 3-lamp fixture, an environmental multi-sensor, a current transducer, and control software. The ACM, dimmable ballast, multi-sensor, and current transducer were all integrated with SmartMesh{trademark} wirelessmore » mesh networking nodes, called motes, enabling wireless communication, sensor monitoring, and actuator control. Each mote-enabled device has a reliable communication path to the SmartMesh Manager, a single board computer that controls network functions and connects the wireless network to a PC running lighting control software. The ACM is capable of locally driving one or more standard 0-10 Volt electronic dimmable ballasts through relay control and a 0-10 Volt controllable output. The mote-integrated electronic dimmable ballast is designed to drive a standard 3-lamp T8 light fixture. The environmental multi-sensor measures occupancy, light level and temperature. The current transducer is used to measure the power consumed by the fixture. Control software was developed to implement advanced lighting algorithms, including daylight ramping, occupancy control, and demand response. Engineering prototypes of each component were fabricated and tested in a bench-scale system. Based on standard industry practices, a cost analysis was conducted. It is estimated that the installation cost of a wireless advanced lighting control system for a retrofit application is at least 30% lower than a comparable wired system for a typical 16,000 square-foot office building, with a payback period of less than 3 years.« less

Application of a COTS Resource Optimization Framework to the SSN Sensor Tasking Domain - Part I: Problem Definition

NASA Astrophysics Data System (ADS)

Tran, T.

With the onset of the SmallSat era, the RSO catalog is expected to see continuing growth in the near future. This presents a significant challenge to the current sensor tasking of the SSN. The Air Force is in need of a sensor tasking system that is robust, efficient, scalable, and able to respond in real-time to interruptive events that can change the tracking requirements of the RSOs. Furthermore, the system must be capable of using processed data from heterogeneous sensors to improve tasking efficiency. The SSN sensor tasking can be regarded as an economic problem of supply and demand: the amount of tracking data needed by each RSO represents the demand side while the SSN sensor tasking represents the supply side. As the number of RSOs to be tracked grows, demand exceeds supply. The decision-maker is faced with the problem of how to allocate resources in the most efficient manner. Braxton recently developed a framework called Multi-Objective Resource Optimization using Genetic Algorithm (MOROUGA) as one of its modern COTS software products. This optimization framework took advantage of the maturing technology of evolutionary computation in the last 15 years. This framework was applied successfully to address the resource allocation of an AFSCN-like problem. In any resource allocation problem, there are five key elements: (1) the resource pool, (2) the tasks using the resources, (3) a set of constraints on the tasks and the resources, (4) the objective functions to be optimized, and (5) the demand levied on the resources. In this paper we explain in detail how the design features of this optimization framework are directly applicable to address the SSN sensor tasking domain. We also discuss our validation effort as well as present the result of the AFSCN resource allocation domain using a prototype based on this optimization framework.

Microelectromechanical Systems

NASA Technical Reports Server (NTRS)

Gabriel, Kaigham J.

1995-01-01

Micro-electromechanical systems (MEMS) is an enabling technology that merges computation and communication with sensing and actuation to change the way people and machines interact with the physical world. MEMS is a manufacturing technology that will impact widespread applications including: miniature inertial measurement measurement units for competent munitions and personal navigation; distributed unattended sensors; mass data storage devices; miniature analytical instruments; embedded pressure sensors; non-invasive biomedical sensors; fiber-optics components and networks; distributed aerodynamic control; and on-demand structural strength. The long term goal of ARPA's MEMS program is to merge information processing with sensing and actuation to realize new systems and strategies for both perceiving and controlling systems, processes, and the environment. The MEMS program has three major thrusts: advanced devices and processes, system design, and infrastructure.

Monitoring Pest Insect Traps by Means of Low-Power Image Sensor Technologies

PubMed Central

López, Otoniel; Rach, Miguel Martinez; Migallon, Hector; Malumbres, Manuel P.; Bonastre, Alberto; Serrano, Juan J.

2012-01-01

Monitoring pest insect populations is currently a key issue in agriculture and forestry protection. At the farm level, human operators typically must perform periodical surveys of the traps disseminated through the field. This is a labor-, time- and cost-consuming activity, in particular for large plantations or large forestry areas, so it would be of great advantage to have an affordable system capable of doing this task automatically in an accurate and a more efficient way. This paper proposes an autonomous monitoring system based on a low-cost image sensor that it is able to capture and send images of the trap contents to a remote control station with the periodicity demanded by the trapping application. Our autonomous monitoring system will be able to cover large areas with very low energy consumption. This issue would be the main key point in our study; since the operational live of the overall monitoring system should be extended to months of continuous operation without any kind of maintenance (i.e., battery replacement). The images delivered by image sensors would be time-stamped and processed in the control station to get the number of individuals found at each trap. All the information would be conveniently stored at the control station, and accessible via Internet by means of available network services at control station (WiFi, WiMax, 3G/4G, etc.). PMID:23202232

Monitoring pest insect traps by means of low-power image sensor technologies.

PubMed

López, Otoniel; Rach, Miguel Martinez; Migallon, Hector; Malumbres, Manuel P; Bonastre, Alberto; Serrano, Juan J

2012-11-13

Monitoring pest insect populations is currently a key issue in agriculture and forestry protection. At the farm level, human operators typically must perform periodical surveys of the traps disseminated through the field. This is a labor-, time- and cost-consuming activity, in particular for large plantations or large forestry areas, so it would be of great advantage to have an affordable system capable of doing this task automatically in an accurate and a more efficient way. This paper proposes an autonomous monitoring system based on a low-cost image sensor that it is able to capture and send images of the trap contents to a remote control station with the periodicity demanded by the trapping application. Our autonomous monitoring system will be able to cover large areas with very low energy consumption. This issue would be the main key point in our study; since the operational live of the overall monitoring system should be extended to months of continuous operation without any kind of maintenance (i.e., battery replacement). The images delivered by image sensors would be time-stamped and processed in the control station to get the number of individuals found at each trap. All the information would be conveniently stored at the control station, and accessible via Internet by means of available network services at control station (WiFi, WiMax, 3G/4G, etc.).

A comparison of reduced-order modelling techniques for application in hyperthermia control and estimation.

PubMed

Bailey, E A; Dutton, A W; Mattingly, M; Devasia, S; Roemer, R B

1998-01-01

Reduced-order modelling techniques can make important contributions in the control and state estimation of large systems. In hyperthermia, reduced-order modelling can provide a useful tool by which a large thermal model can be reduced to the most significant subset of its full-order modes, making real-time control and estimation possible. Two such reduction methods, one based on modal decomposition and the other on balanced realization, are compared in the context of simulated hyperthermia heat transfer problems. The results show that the modal decomposition reduction method has three significant advantages over that of balanced realization. First, modal decomposition reduced models result in less error, when compared to the full-order model, than balanced realization reduced models of similar order in problems with low or moderate advective heat transfer. Second, because the balanced realization based methods require a priori knowledge of the sensor and actuator placements, the reduced-order model is not robust to changes in sensor or actuator locations, a limitation not present in modal decomposition. Third, the modal decomposition transformation is less demanding computationally. On the other hand, in thermal problems dominated by advective heat transfer, numerical instabilities make modal decomposition based reduction problematic. Modal decomposition methods are therefore recommended for reduction of models in which advection is not dominant and research continues into methods to render balanced realization based reduction more suitable for real-time clinical hyperthermia control and estimation.

On-demand information retrieval in sensor networks with localised query and energy-balanced data collection.

PubMed

Teng, Rui; Zhang, Bing

2011-01-01

On-demand information retrieval enables users to query and collect up-to-date sensing information from sensor nodes. Since high energy efficiency is required in a sensor network, it is desirable to disseminate query messages with small traffic overhead and to collect sensing data with low energy consumption. However, on-demand query messages are generally forwarded to sensor nodes in network-wide broadcasts, which create large traffic overhead. In addition, since on-demand information retrieval may introduce intermittent and spatial data collections, the construction and maintenance of conventional aggregation structures such as clusters and chains will be at high cost. In this paper, we propose an on-demand information retrieval approach that exploits the name resolution of data queries according to the attribute and location of each sensor node. The proposed approach localises each query dissemination and enable localised data collection with maximised aggregation. To illustrate the effectiveness of the proposed approach, an analytical model that describes the criteria of sink proxy selection is provided. The evaluation results reveal that the proposed scheme significantly reduces energy consumption and improves the balance of energy consumption among sensor nodes by alleviating heavy traffic near the sink.

Mathematical calibration procedure of a capacitive sensor-based indexed metrology platform

NASA Astrophysics Data System (ADS)

Brau-Avila, A.; Santolaria, J.; Acero, R.; Valenzuela-Galvan, M.; Herrera-Jimenez, V. M.; Aguilar, J. J.

2017-03-01

The demand for faster and more reliable measuring tasks for the control and quality assurance of modern production systems has created new challenges for the field of coordinate metrology. Thus, the search for new solutions in coordinate metrology systems and the need for the development of existing ones still persists. One example of such a system is the portable coordinate measuring machine (PCMM), the use of which in industry has considerably increased in recent years, mostly due to its flexibility for accomplishing in-line measuring tasks as well as its reduced cost and operational advantages compared to traditional coordinate measuring machines. Nevertheless, PCMMs have a significant drawback derived from the techniques applied in the verification and optimization procedures of their kinematic parameters. These techniques are based on the capture of data with the measuring instrument from a calibrated gauge object, fixed successively in various positions so that most of the instrument measuring volume is covered, which results in time-consuming, tedious and expensive verification and optimization procedures. In this work the mathematical calibration procedure of a capacitive sensor-based indexed metrology platform (IMP) is presented. This calibration procedure is based on the readings and geometric features of six capacitive sensors and their targets with nanometer resolution. The final goal of the IMP calibration procedure is to optimize the geometric features of the capacitive sensors and their targets in order to use the optimized data in the verification procedures of PCMMs.

Automatic start control for a three-phase electric motor using infrared sensors

NASA Astrophysics Data System (ADS)

Echenique Lima, Mario; Ramírez Arenas, Francisco; Rodríguez Pedroza, Griselda

2006-02-01

We introduce equipment for the automatic activation of a three-phase electric motor (1Hp, 3A, 240V AC) using 2 infrared sensors monitored by a Microchip microcontroller PIC16F62x@4Mhz for the control of a filling system. This project was carried out to Fabrica de Chocolates y Dulces Costanzo, where the automatization of cacao grain supply was required for a machine in charge of cleaning the cacao from its rind. This process demanded the monitoring of the filling level to avoid the spill of toasted cacao.

SERS-based pesticide detection by using nanofinger sensors

NASA Astrophysics Data System (ADS)

Kim, Ansoon; Barcelo, Steven J.; Li, Zhiyong

2015-01-01

Simple, sensitive, and rapid detection of trace levels of extensively used and highly toxic pesticides are in urgent demand for public health. Surface-enhanced Raman scattering (SERS)-based sensor was designed to achieve ultrasensitive and simple pesticide sensing. We developed a portable sensor system composed of high performance and reliable gold nanofinger sensor strips and a custom-built portable Raman spectrometer. Compared to the general procedure and previously reported studies that are limited to laboratory settings, our analytical method is simple, sensitive, rapid, and cost-effective. Based on the SERS results, the chemical interaction of two pesticides, chlorpyrifos (CPF) and thiabendazole (TBZ), with gold nanofingers was studied to determine a fingerprint for each pesticide. The portable SERS-sensor system was successfully demonstrated to detect CPF and TBZ pesticides within 15 min with a detection limit of 35 ppt in drinking water and 7 ppb on apple skin, respectively.

Relative-Motion Sensors and Actuators for Two Optical Tables

NASA Technical Reports Server (NTRS)

Gursel, Yekta; McKenney, Elizabeth

2004-01-01

Optoelectronic sensors and magnetic actuators have been developed as parts of a system for controlling the relative position and attitude of two massive optical tables that float on separate standard air suspensions that attenuate ground vibrations. In the specific application for which these sensors and actuators were developed, one of the optical tables holds an optical system that mimics distant stars, while the other optical table holds a test article that simulates a spaceborne stellar interferometer that would be used to observe the stars. The control system is designed to suppress relative motion of the tables or, on demand, to impose controlled relative motion between the tables. The control system includes a sensor system that detects relative motion of the tables in six independent degrees of freedom and a drive system that can apply force to the star-simulator table in the six degrees of freedom. The sensor system includes (1) a set of laser heterodyne gauges and (2) a set of four diode lasers on the star-simulator table, each aimed at one of four quadrant photodiodes at nominal corresponding positions on the test-article table. The heterodyne gauges are used to measure relative displacements along the x axis.

Multi-Axis Force Sensor for Human-Robot Interaction Sensing in a Rehabilitation Robotic Device.

PubMed

Grosu, Victor; Grosu, Svetlana; Vanderborght, Bram; Lefeber, Dirk; Rodriguez-Guerrero, Carlos

2017-06-05

Human-robot interaction sensing is a compulsory feature in modern robotic systems where direct contact or close collaboration is desired. Rehabilitation and assistive robotics are fields where interaction forces are required for both safety and increased control performance of the device with a more comfortable experience for the user. In order to provide an efficient interaction feedback between the user and rehabilitation device, high performance sensing units are demanded. This work introduces a novel design of a multi-axis force sensor dedicated for measuring pelvis interaction forces in a rehabilitation exoskeleton device. The sensor is conceived such that it has different sensitivity characteristics for the three axes of interest having also movable parts in order to allow free rotations and limit crosstalk errors. Integrated sensor electronics make it easy to acquire and process data for a real-time distributed system architecture. Two of the developed sensors are integrated and tested in a complex gait rehabilitation device for safe and compliant control.

Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch.

PubMed

Huang, Tao; Yan, Siyu; Yang, Fan; Pan, Tian; Liu, Jiang

2016-01-19

Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture.

Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch

PubMed Central

Huang, Tao; Yan, Siyu; Yang, Fan; Pan, Tian; Liu, Jiang

2016-01-01

Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture. PMID:26797616

Remote sensing of global croplands for food security

USGS Publications Warehouse

Thenkabail, Prasad S.; Biradar, Chandrashekhar M.; Turral, Hugh; Lyon, John G.

2009-01-01

Increases in populations have created an increasing demand for food crops while increases in demand for biofuels have created an increase in demand for fuel crops. What has not increased is the amount of croplands and their productivity. These and many other factors such as decreasing water resources in a changing climate have created a crisis like situation in global food security. Decision makers in these situations need accurate information based on science. Remote Sensing of Global Croplands for Food Security provides a comprehensive knowledge base in use of satellite sensor-based maps and statistics that can be used to develop strategies for croplands (irrigated and rainfed) and their water use for food security.

Wireless sensing and vibration control with increased redundancy and robustness design.

PubMed

Li, Peng; Li, Luyu; Song, Gangbing; Yu, Yan

2014-11-01

Control systems with long distance sensor and actuator wiring have the problem of high system cost and increased sensor noise. Wireless sensor network (WSN)-based control systems are an alternative solution involving lower setup and maintenance costs and reduced sensor noise. However, WSN-based control systems also encounter problems such as possible data loss, irregular sampling periods (due to the uncertainty of the wireless channel), and the possibility of sensor breakdown (due to the increased complexity of the overall control system). In this paper, a wireless microcontroller-based control system is designed and implemented to wirelessly perform vibration control. The wireless microcontroller-based system is quite different from regular control systems due to its limited speed and computational power. Hardware, software, and control algorithm design are described in detail to demonstrate this prototype. Model and system state compensation is used in the wireless control system to solve the problems of data loss and sensor breakdown. A positive position feedback controller is used as the control law for the task of active vibration suppression. Both wired and wireless controllers are implemented. The results show that the WSN-based control system can be successfully used to suppress the vibration and produces resilient results in the presence of sensor failure.

Optimized autonomous space in-situ sensor web for volcano monitoring

USGS Publications Warehouse

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

2010-01-01

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

RIDES: Robust Intrusion Detection System for IP-Based Ubiquitous Sensor Networks

PubMed Central

Amin, Syed Obaid; Siddiqui, Muhammad Shoaib; Hong, Choong Seon; Lee, Sungwon

2009-01-01

The IP-based Ubiquitous Sensor Network (IP-USN) is an effort to build the “Internet of things”. By utilizing IP for low power networks, we can benefit from existing well established tools and technologies of IP networks. Along with many other unresolved issues, securing IP-USN is of great concern for researchers so that future market satisfaction and demands can be met. Without proper security measures, both reactive and proactive, it is hard to envisage an IP-USN realm. In this paper we present a design of an IDS (Intrusion Detection System) called RIDES (Robust Intrusion DEtection System) for IP-USN. RIDES is a hybrid intrusion detection system, which incorporates both Signature and Anomaly based intrusion detection components. For signature based intrusion detection this paper only discusses the implementation of distributed pattern matching algorithm with the help of signature-code, a dynamically created attack-signature identifier. Other aspects, such as creation of rules are not discussed. On the other hand, for anomaly based detection we propose a scoring classifier based on the SPC (Statistical Process Control) technique called CUSUM charts. We also investigate the settings and their effects on the performance of related parameters for both of the components. PMID:22412321

RIDES: Robust Intrusion Detection System for IP-Based Ubiquitous Sensor Networks.

PubMed

Amin, Syed Obaid; Siddiqui, Muhammad Shoaib; Hong, Choong Seon; Lee, Sungwon

2009-01-01

The IP-based Ubiquitous Sensor Network (IP-USN) is an effort to build the "Internet of things". By utilizing IP for low power networks, we can benefit from existing well established tools and technologies of IP networks. Along with many other unresolved issues, securing IP-USN is of great concern for researchers so that future market satisfaction and demands can be met. Without proper security measures, both reactive and proactive, it is hard to envisage an IP-USN realm. In this paper we present a design of an IDS (Intrusion Detection System) called RIDES (Robust Intrusion DEtection System) for IP-USN. RIDES is a hybrid intrusion detection system, which incorporates both Signature and Anomaly based intrusion detection components. For signature based intrusion detection this paper only discusses the implementation of distributed pattern matching algorithm with the help of signature-code, a dynamically created attack-signature identifier. Other aspects, such as creation of rules are not discussed. On the other hand, for anomaly based detection we propose a scoring classifier based on the SPC (Statistical Process Control) technique called CUSUM charts. We also investigate the settings and their effects on the performance of related parameters for both of the components.

Sensors for rate responsive pacing

PubMed Central

Dell'Orto, Simonetta; Valli, Paolo; Greco, Enrico Maria

2004-01-01

Advances in pacemaker technology in the 1980s have generated a wide variety of complex multiprogrammable pacemakers and pacing modes. The aim of the present review is to address the different rate responsive pacing modalities presently available in respect to physiological situations and pathological conditions. Rate adaptive pacing has been shown to improve exercise capacity in patients with chronotropic incompetence. A number of activity and metabolic sensors have been proposed and used for rate control. However, all sensors used to optimize pacing rate metabolic demands show typical limitations. To overcome these weaknesses the use of two sensors has been proposed. Indeed an unspecific but fast reacting sensor is combined with a more specific but slower metabolic one. Clinical studies have demonstrated that this methodology is suitable to reproduce normal sinus behavior during different types and loads of exercise. Sensor combinations require adequate sensor blending and cross checking possibly controlled by automatic algorithms for sensors optimization and simplicity of programming. Assessment and possibly deactivation of some automatic functions should be also possible to maximize benefits from the dual sensor system in particular conditions. This is of special relevance in patient whose myocardial contractility is limited such as in subjects with implantable defibrillators and biventricular pacemakers. The concept of closed loop pacing, implementing a negative feedback relating pacing rate and the control signal, will provide new opportunities to optimize dual-sensors system and deserves further investigation. The integration of rate adaptive pacing into defibrillators is the natural consequence of technical evolution. PMID:16943981

Microelectromechanical Systems; A DoD Dual Use Technology Industrial Assessment.

DTIC Science & Technology

1995-12-01

systems, • embedded sensors and actuators for condition-based maintenance of machines and vehicles, on-demand amplified structural strength in...will transmit temperature, pressure, and number-of- rotations information to a hand-held receiver used by the maintenance and service personnel. This...automobile industry being the major driver for most micro- machined sensors (pressure, acceleration and oxygen). In 1994 model year Projected Growth

Radiation tolerant compact image sensor using CdTe photodiode and field emitter array (Conference Presentation)

NASA Astrophysics Data System (ADS)

Masuzawa, Tomoaki; Neo, Yoichiro; Mimura, Hidenori; Okamoto, Tamotsu; Nagao, Masayoshi; Akiyoshi, Masafumi; Sato, Nobuhiro; Takagi, Ikuji; Tsuji, Hiroshi; Gotoh, Yasuhito

2016-10-01

A growing demand on incident detection is recognized since the Great East Japan Earthquake and successive accidents in Fukushima nuclear power plant in 2011. Radiation tolerant image sensors are powerful tools to collect crucial information at initial stages of such incidents. However, semiconductor based image sensors such as CMOS and CCD have limited tolerance to radiation exposure. Image sensors used in nuclear facilities are conventional vacuum tubes using thermal cathodes, which have large size and high power consumption. In this study, we propose a compact image sensor composed of a CdTe-based photodiode and a matrix-driven Spindt-type electron beam source called field emitter array (FEA). A basic principle of FEA-based image sensors is similar to conventional Vidicon type camera tubes, but its electron source is replaced from a thermal cathode to FEA. The use of a field emitter as an electron source should enable significant size reduction while maintaining high radiation tolerance. Current researches on radiation tolerant FEAs and development of CdTe based photoconductive films will be presented.

An embedded stress sensor for concrete SHM based on amorphous ferromagnetic microwires.

PubMed

Olivera, Jesús; González, Margarita; Fuente, José Vicente; Varga, Rastislav; Zhukov, Arkady; Anaya, José Javier

2014-10-24

A new smart concrete aggregate design as a candidate for applications in structural health monitoring (SHM) of critical elements in civil infrastructure is proposed. The cement-based stress/strain sensor was developed by utilizing the stress/strain sensing properties of a magnetic microwire embedded in cement-based composite (MMCC). This is a contact-less type sensor that measures variations of magnetic properties resulting from stress variations. Sensors made of these materials can be designed to satisfy the specific demand for an economic way to monitor concrete infrastructure health. For this purpose, we embedded a thin magnetic microwire in the core of a cement-based cylinder, which was inserted into the concrete specimen under study as an extra aggregate. The experimental results show that the embedded MMCC sensor is capable of measuring internal compressive stress around the range of 1-30 MPa. Two stress sensing properties of the embedded sensor under uniaxial compression were studied: the peak amplitude and peak position of magnetic switching field. The sensitivity values for the amplitude and position within the measured range were 5 mV/MPa and 2.5 µs/MPa, respectively.

Multimodal control of sensors on multiple simulated unmanned vehicles.

PubMed

Baber, C; Morin, C; Parekh, M; Cahillane, M; Houghton, R J

2011-09-01

The use of multimodal (speech plus manual) control of the sensors on combinations of one, two, three or five simulated unmanned vehicles (UVs) is explored. Novice controllers of simulated UVs complete a series of target checking tasks. Two experiments compare speech and gamepad control for one, two, three or five UVs in a simulated environment. Increasing the number of UVs has an impact on subjective rating of workload (measured by NASA-Task Load Index), particularly when moving from one to three UVs. Objective measures of performance showed that the participants tended to issue fewer commands as the number of vehicles increased (when using the gamepad control), but, while performance with a single UV was superior to that of multiple UVs, there was little difference across two, three or five UVs. Participants with low spatial ability (measured by the Object Perspectives Test) showed an increase in time to respond to warnings when controlling five UVs. Combining speech with gamepad control of sensors on UVs leads to superior performance on a secondary (respond-to-warnings) task (implying a reduction in demand) and use of fewer commands on primary (move-sensors and classify-target) tasks (implying more efficient operation). STATEMENT OF RELEVANCE: Benefits of multimodal control for unmanned vehicles are demonstrated. When controlling sensors on multiple UVs, participants with low spatial orientation scores have problems. It is proposed that the findings of these studies have implications for selection of UV operators and suggests that future UV workstations could benefit from multimodal control.

Application of ion-sensitive sensors in water quality monitoring.

PubMed

Winkler, S; Rieger, L; Saracevic, E; Pressl, A; Gruber, G

2004-01-01

Within the last years a trend towards in-situ monitoring can be observed, i.e. most new sensors for water quality monitoring are designed for direct installation in the medium, compact in size and use measurement principles which minimise maintenance demand. Ion-sensitive sensors (Ion-Sensitive-Electrode--ISE) are based on a well known measurement principle and recently some manufacturers have released probe types which are specially adapted for application in water quality monitoring. The function principle of ISE-sensors, their advantages, limitations and the different methods for sensor calibration are described. Experiences with ISE-sensors from applications in sewer networks, at different sampling points within wastewater treatment plants and for surface water monitoring are reported. An estimation of investment and operation costs in comparison to other sensor types is given.

Ubiquitous Green Computing Techniques for High Demand Applications in Smart Environments

PubMed Central

Zapater, Marina; Sanchez, Cesar; Ayala, Jose L.; Moya, Jose M.; Risco-Martín, José L.

2012-01-01

Ubiquitous sensor network deployments, such as the ones found in Smart cities and Ambient intelligence applications, require constantly increasing high computational demands in order to process data and offer services to users. The nature of these applications imply the usage of data centers. Research has paid much attention to the energy consumption of the sensor nodes in WSNs infrastructures. However, supercomputing facilities are the ones presenting a higher economic and environmental impact due to their very high power consumption. The latter problem, however, has been disregarded in the field of smart environment services. This paper proposes an energy-minimization workload assignment technique, based on heterogeneity and application-awareness, that redistributes low-demand computational tasks from high-performance facilities to idle nodes with low and medium resources in the WSN infrastructure. These non-optimal allocation policies reduce the energy consumed by the whole infrastructure and the total execution time. PMID:23112621

Ubiquitous green computing techniques for high demand applications in Smart environments.

PubMed

Zapater, Marina; Sanchez, Cesar; Ayala, Jose L; Moya, Jose M; Risco-Martín, José L

2012-01-01

Ubiquitous sensor network deployments, such as the ones found in Smart cities and Ambient intelligence applications, require constantly increasing high computational demands in order to process data and offer services to users. The nature of these applications imply the usage of data centers. Research has paid much attention to the energy consumption of the sensor nodes in WSNs infrastructures. However, supercomputing facilities are the ones presenting a higher economic and environmental impact due to their very high power consumption. The latter problem, however, has been disregarded in the field of smart environment services. This paper proposes an energy-minimization workload assignment technique, based on heterogeneity and application-awareness, that redistributes low-demand computational tasks from high-performance facilities to idle nodes with low and medium resources in the WSN infrastructure. These non-optimal allocation policies reduce the energy consumed by the whole infrastructure and the total execution time.

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.

2012-01-01

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 next generation CO2 sensing technology with performance beyond that presently in use on the 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 (LD) spectrometer based on wavelength modulation spectroscopy (WMS) 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 (O2) channel using a vertical cavity surface emitting laser (VCSEL). Both prototypes are controlled digitally with a field-programmable gate array (FPGA)/microcontroller architecture. Based on the results of the initial instrument development, further prototype development and testing of instruments leveraging the lessons learned were desired. 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. .

Concept and integration of an on-line quasi-operational airborne hyperspectral remote sensing system

NASA Astrophysics Data System (ADS)

Schilling, Hendrik; Lenz, Andreas; Gross, Wolfgang; Perpeet, Dominik; Wuttke, Sebastian; Middelmann, Wolfgang

2013-10-01

Modern mission characteristics require the use of advanced imaging sensors in reconnaissance. In particular, high spatial and high spectral resolution imaging provides promising data for many tasks such as classification and detecting objects of military relevance, such as camouflaged units or improvised explosive devices (IEDs). Especially in asymmetric warfare with highly mobile forces, intelligence, surveillance and reconnaissance (ISR) needs to be available close to real-time. This demands the use of unmanned aerial vehicles (UAVs) in combination with downlink capability. The system described in this contribution is integrated in a wing pod for ease of installation and calibration. It is designed for the real-time acquisition and analysis of hyperspectral data. The main component is a Specim AISA Eagle II hyperspectral sensor, covering the visible and near-infrared (VNIR) spectral range with a spectral resolution up to 1.2 nm and 1024 pixel across track, leading to a ground sampling distance below 1 m at typical altitudes. The push broom characteristic of the hyperspectral sensor demands an inertial navigation system (INS) for rectification and georeferencing of the image data. Additional sensors are a high resolution RGB (HR-RGB) frame camera and a thermal imaging camera. For on-line application, the data is preselected, compressed and transmitted to the ground control station (GCS) by an existing system in a second wing pod. The final result after data processing in the GCS is a hyperspectral orthorectified GeoTIFF, which is filed in the ERDAS APOLLO geographical information system. APOLLO allows remote access to the data and offers web-based analysis tools. The system is quasi-operational and was successfully tested in May 2013 in Bremerhaven, Germany.

Thermal-Performance Instability in Piezoresistive Sensors: Inducement and Improvement

PubMed Central

Liu, Yan; Wang, Hai; Zhao, Wei; Qin, Hongbo; Fang, Xuan

2016-01-01

The field of piezoresistive sensors has been undergoing a significant revolution in terms of design methodology, material technology and micromachining process. However, the temperature dependence of sensor characteristics remains a hurdle to cross. This review focuses on the issues in thermal-performance instability of piezoresistive sensors. Based on the operation fundamental, inducements to the instability are investigated in detail and correspondingly available ameliorative methods are presented. Pros and cons of each improvement approach are also summarized. Though several schemes have been proposed and put into reality with favorable achievements, the schemes featuring simple implementation and excellent compatibility with existing techniques are still emergently demanded to construct a piezoresistive sensor with excellent comprehensive performance. PMID:27886125

Eyeglasses based wireless electrolyte and metabolite sensor platform.

PubMed

Sempionatto, Juliane R; Nakagawa, Tatsuo; Pavinatto, Adriana; Mensah, Samantha T; Imani, Somayeh; Mercier, Patrick; Wang, Joseph

2017-05-16

The demand for wearable sensors has grown rapidly in recent years, with increasing attention being given to epidermal chemical sensing. Here, we present the first example of a fully integrated eyeglasses wireless multiplexed chemical sensing platform capable of real-time monitoring of sweat electrolytes and metabolites. The new concept has been realized by integrating an amperometric lactate biosensor and a potentiometric potassium ion-selective electrode into the two nose-bridge pads of the glasses and interfacing them with a wireless electronic backbone placed on the glasses' arms. Simultaneous real-time monitoring of sweat lactate and potassium levels with no apparent cross-talk is demonstrated along with wireless signal transduction. The electrochemical sensors were screen-printed on polyethylene terephthalate (PET) stickers and placed on each side of the glasses' nose pads in order to monitor sweat metabolites and electrolytes. The electronic backbone on the arms of the glasses' frame offers control of the amperometric and potentiometric transducers and enables Bluetooth wireless data transmission to the host device. The new eyeglasses system offers an interchangeable-sensor feature in connection with a variety of different nose-bridge amperometric and potentiometric sensor stickers. For example, the lactate bridge-pad sensor was replaced with a glucose one to offer convenient monitoring of sweat glucose. Such a fully integrated wireless "Lab-on-a-Glass" multiplexed biosensor platform can be readily expanded for the simultaneous monitoring of additional sweat electrolytes and metabolites.

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.

Simple autonomous Mars walker

NASA Technical Reports Server (NTRS)

Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.

1989-01-01

Under a contract with NASA's Jet Propulsion Laboratory, Martin Marietta has developed several alternative rover concepts for unmanned exploration of the planet Mars. One of those concepts, the 'Walking Beam', is the subject of this paper. This concept was developed with the goal of achieving many of the capabilities of more sophisticated articulated-leg walkers with a much simpler, more robust, less computationally demanding and more power efficient design. It consists of two large-base tripods nested one within the other which alternately translate with respect to each other along a 5-meter beam to propel the vehicle. The semiautonomous navigation system relies on terrain geometry sensors and tacticle feedback from each foot to autonomously select a path which avoids hazards along a route designated from earth. Both mobility and navigation features of this concept are discussed including a top-level description of the vehicle's physical characteristics, deployment strategy, mobility elements, sensor suite, theory of operation, navigation and control processes, and estimated performance.

Chalcogenide glass sensors for bio-molecule detection

NASA Astrophysics Data System (ADS)

Lucas, Pierre; Coleman, Garrett J.; Cantoni, Christopher; Jiang, Shibin; Luo, Tao; Bureau, Bruno; Boussard-Pledel, Catherine; Troles, Johann; Yang, Zhiyong

2017-02-01

Chalcogenide glasses constitute the only class of materials that remain fully amorphous while exhibiting broad optical transparency over the full infrared region from 2-20 microns. As such, they can be shaped into complex optical elements while retaining a clear optical window that encompass the vibrational signals of virtually any molecules. Chalcogenide glasses are therefore ideal materials for designing biological and chemical sensors based on vibrational spectroscopy. In this paper we review the properties of these glasses and the corresponding design of optical elements for bio-chemical sensing. Amorphous chalcogenides offer a very wide compositional landscape that permit to tune their physical properties to match specific demands for the production of optical devices. This includes tailoring the infrared window over specific ranges of wavelength such as the long-wave infrared region to capture important vibrational signal including the "signature region" of micro-organisms or the bending mode of CO2 molecules. Additionally, compositional engineering enables tuning the viscosity-temperature dependence of the glass melt in order to control the rheological properties that are fundamental to the production of glass elements. Indeed, exquisite control of the viscosity is key to the fabrication process of many optical elements such as fiber drawing, lens molding, surface embossing or reflow of microresonators. Optimal control of these properties then enables the design and fabrication of optimized infrared sensors such as Fiber Evanescent Wave Spectroscopy (FEWS) sensors, Whispering Gallery Modes (WGM) micro-resonator sensors, nanostructured surfaces for integrated optics and surface-enhanced processes, or lens molding for focused collection of infrared signals. Many of these sensor designs can be adapted to collect and monitor the vibrational signal of live microorganisms to study their metabolism in controlled environmental conditions. Further materials engineering enable the design of opto-electrophoretic sensors that permit simultaneous capture and detection of hazardous bio-molecules such as bacteria, virus and proteins using a conducting glass that serves as both an electrode and an optical elements. Upon adequate spectral analysis such as Principal Component Analysis (PCA) or Partial Least Square (PLS) regression these devices enable highly selective identification of hazardous microorganism such as different strains of bacteria and food pathogens.

Sensor Management for Applied Research Technologies (SMART)-On Demand Modeling (ODM) Project

NASA Technical Reports Server (NTRS)

Goodman, M.; Blakeslee, R.; Hood, R.; Jedlovec, G.; Botts, M.; Li, X.

2006-01-01

NASA requires timely on-demand data and analysis capabilities to enable practical benefits of Earth science observations. However, a significant challenge exists in accessing and integrating data from multiple sensors or platforms to address Earth science problems because of the large data volumes, varying sensor scan characteristics, unique orbital coverage, and the steep learning curve associated with each sensor and data type. The development of sensor web capabilities to autonomously process these data streams (whether real-time or archived) provides an opportunity to overcome these obstacles and facilitate the integration and synthesis of Earth science data and weather model output. A three year project, entitled Sensor Management for Applied Research Technologies (SMART) - On Demand Modeling (ODM), will develop and demonstrate the readiness of Open Geospatial Consortium (OGC) Sensor Web Enablement (SWE) capabilities that integrate both Earth observations and forecast model output into new data acquisition and assimilation strategies. The advancement of SWE-enabled systems (i.e., use of SensorML, sensor planning services - SPS, sensor observation services - SOS, sensor alert services - SAS and common observation model protocols) will have practical and efficient uses in the Earth science community for enhanced data set generation, real-time data assimilation with operational applications, and for autonomous sensor tasking for unique data collection.

A low power medium access control protocol for wireless medical sensor networks.

PubMed

Lamprinos, I; Prentza, A; Sakka, E; Koutsouris, D

2004-01-01

The concept of a wireless integrated network of sensors, already applied in several sectors of our everyday life, such as security, transportation and environment monitoring, can as well provide an advanced monitor and control resource for healthcare services. By networking medical sensors wirelessly, attaching them in patient's body, we create the appropriate infrastructure for continuous and real-time monitoring of patient without discomforting him. This infrastructure can improve healthcare by providing the means for flexible acquisition of vital signs, while at the same time it provides more convenience to the patient. Given the type of wireless network, traditional medium access control (MAC) protocols cannot take advantage of the application specific requirements and information characteristics occurring in medical sensor networks, such as the demand for low power consumption and the rather limited and asymmetric data traffic. In this paper, we present the architecture of a low power MAC protocol, designated to support wireless networks of medical sensors. This protocol aims to improve energy efficiency by exploiting the inherent application features and requirements. It is oriented towards the avoidance of main energy wastage sources, such as idle listening, collision and power outspending.

A New Cellular Architecture for Information Retrieval from Sensor Networks through Embedded Service and Security Protocols

PubMed Central

Shahzad, Aamir; Landry, René; Lee, Malrey; Xiong, Naixue; Lee, Jongho; Lee, Changhoon

2016-01-01

Substantial changes have occurred in the Information Technology (IT) sectors and with these changes, the demand for remote access to field sensor information has increased. This allows visualization, monitoring, and control through various electronic devices, such as laptops, tablets, i-Pads, PCs, and cellular phones. The smart phone is considered as a more reliable, faster and efficient device to access and monitor industrial systems and their corresponding information interfaces anywhere and anytime. This study describes the deployment of a protocol whereby industrial system information can be securely accessed by cellular phones via a Supervisory Control And Data Acquisition (SCADA) server. To achieve the study goals, proprietary protocol interconnectivity with non-proprietary protocols and the usage of interconnectivity services are considered in detail. They support the visualization of the SCADA system information, and the related operations through smart phones. The intelligent sensors are configured and designated to process real information via cellular phones by employing information exchange services between the proprietary protocol and non-proprietary protocols. SCADA cellular access raises the issue of security flaws. For these challenges, a cryptography-based security method is considered and deployed, and it could be considered as a part of a proprietary protocol. Subsequently, transmission flows from the smart phones through a cellular network. PMID:27314351

A New Cellular Architecture for Information Retrieval from Sensor Networks through Embedded Service and Security Protocols.

PubMed

Shahzad, Aamir; Landry, René; Lee, Malrey; Xiong, Naixue; Lee, Jongho; Lee, Changhoon

2016-06-14

Substantial changes have occurred in the Information Technology (IT) sectors and with these changes, the demand for remote access to field sensor information has increased. This allows visualization, monitoring, and control through various electronic devices, such as laptops, tablets, i-Pads, PCs, and cellular phones. The smart phone is considered as a more reliable, faster and efficient device to access and monitor industrial systems and their corresponding information interfaces anywhere and anytime. This study describes the deployment of a protocol whereby industrial system information can be securely accessed by cellular phones via a Supervisory Control And Data Acquisition (SCADA) server. To achieve the study goals, proprietary protocol interconnectivity with non-proprietary protocols and the usage of interconnectivity services are considered in detail. They support the visualization of the SCADA system information, and the related operations through smart phones. The intelligent sensors are configured and designated to process real information via cellular phones by employing information exchange services between the proprietary protocol and non-proprietary protocols. SCADA cellular access raises the issue of security flaws. For these challenges, a cryptography-based security method is considered and deployed, and it could be considered as a part of a proprietary protocol. Subsequently, transmission flows from the smart phones through a cellular network.

Sensors-network and its application in the intelligent storage security

NASA Astrophysics Data System (ADS)

Zhang, Qingying; Nicolescu, Mihai; Jiang, Xia; Zhang, Ying; Yue, Weihong; Xiao, Weihong

2004-11-01

Intelligent storage systems run on different advanced technologies, such as linear layout, business intelligence and data mining. Security, the basic desire of the storage system, has been focused on with the indraught of multimedia communication technology and sensors" network. Along with the developing of science and the social demands, multifarious alarming system has been designed and improved to be intelligentized, modularized and have network connections. It is of great moment to make the storage, and further more, the logistics system more and more efficient and perfect with modern science and technology. Diversified information on the spot should be caught by different kinds of sensors. Those signals are treated and communicated to the control center to give the further actions. For fire-proofing, broad-spectrum gas sensors, fume sensors, flame sensors and temperature sensors are used to catch the information in their own ways. Once the fire is taken somewhere, the sensors work by the fume, temperature, and flame as well as gas immediately. Meanwhile the intelligent control system starts. It passes the tidings to the center unit. At the same time, it sets those movable walls on to work quickly to obstruct the fire"s spreading. While for guarding the warehouse against theft, cut-off sensors, body sensors, photoelectric sensors, microwave sensors and closed-circuit television as well as electronic clocks are available to monitor the warehouse reasonably. All of those sensors work in a net way. The intelligent control system is made with a digital circuit instead of traditional switch one. This system can work in a better way in many cases. Its reliability is high and the cost is low.

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

PubMed Central

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

2017-01-01

With the combination of micropumps and flow sensors, highly accurate and secure closed-loop controlled micro dosing systems for liquids are possible. Implementing a single stroke based control mode with piezoelectrically driven micro diaphragm pumps can provide a solution for dosing of volumes down to nanoliters or variable average flow rates in the range of nL/min to μL/min. However, sensor technologies feature a yet undetermined accuracy for measuring highly pulsatile micropump flow. Two miniaturizable in-line sensor types providing electrical readout—differential pressure based flow sensors and thermal calorimetric flow sensors—are evaluated for their suitability of combining them with mircopumps. Single stroke based calibration of the sensors was carried out with a new method, comparing displacement volumes and sensor flow volumes. Limitations of accuracy and performance for single stroke based flow control are described. Results showed that besides particle robustness of sensors, controlling resistive and capacitive damping are key aspects for setting up reproducible and reliable liquid dosing systems. Depending on the required average flow or defined volume, dosing systems with an accuracy of better than 5% for the differential pressure based sensor and better than 6.5% for the thermal calorimeter were achieved. PMID:28368344

High temperature and frequency pressure sensor based on silicon-on-insulator layers

NASA Astrophysics Data System (ADS)

Zhao, Y. L.; Zhao, L. B.; Jiang, Z. D.

2006-03-01

Based on silicon on insulator (SOI) technology, a novel high temperature pressure sensor with high frequency response is designed and fabricated, in which a buried silicon dioxide layer in the silicon material is developed by the separation by implantation of oxygen (SIMOX) technology. This layer can isolate leak currents between the top silicon layer for the detecting circuit and body silicon at a temperature of about 200 °C. In addition, the technology of silicon and glass bonding is used to create a package of the sensor without internal strain. A structural model and test data from the sensor are presented. The experimental results showed that this kind of sensor possesses good static performance in a high temperature environment and high frequency dynamic characteristics, which may satisfy the pressure measurement demands of the oil industry, aviation and space, and so on.

Belief Function Based Decision Fusion for Decentralized Target Classification in Wireless Sensor Networks

PubMed Central

Zhang, Wenyu; Zhang, Zhenjiang

2015-01-01

Decision fusion in sensor networks enables sensors to improve classification accuracy while reducing the energy consumption and bandwidth demand for data transmission. In this paper, we focus on the decentralized multi-class classification fusion problem in wireless sensor networks (WSNs) and a new simple but effective decision fusion rule based on belief function theory is proposed. Unlike existing belief function based decision fusion schemes, the proposed approach is compatible with any type of classifier because the basic belief assignments (BBAs) of each sensor are constructed on the basis of the classifier’s training output confusion matrix and real-time observations. We also derive explicit global BBA in the fusion center under Dempster’s combinational rule, making the decision making operation in the fusion center greatly simplified. Also, sending the whole BBA structure to the fusion center is avoided. Experimental results demonstrate that the proposed fusion rule has better performance in fusion accuracy compared with the naïve Bayes rule and weighted majority voting rule. PMID:26295399

A survey of life support system automation and control

NASA Technical Reports Server (NTRS)

Finn, Cory K.

1993-01-01

The level of automation and control necessary to support advanced life support systems for use in the manned space program is steadily increasing. As the length and complexity of manned missions increase, life support systems must be able to meet new space challenges. Longer, more complex missions create new demands for increased automation, improved sensors, and improved control systems. It is imperative that research in these key areas keep pace with current and future developments in regenerative life support technology. This paper provides an overview of past and present research in the areas of sensor development, automation, and control of life support systems for the manned space program, and it discusses the impact continued research in several key areas will have on the feasibility, operation, and design of future life support systems.

A high-temperature shape memory alloy sensor for combustion monitoring and control

NASA Astrophysics Data System (ADS)

Shaw, Greg S.; Snyder, Joseph T.; Prince, Troy S.; Willett, Michael C.

2005-05-01

Innovations in the use of thin film SMA materials have enabled the development of a harsh environment pressure sensor useful for combustion monitoring and control. Development of such active combustion control has been driven by rising fuel costs and environmental pressures. Active combustion control, whether in diesel, spark ignited or turbine engines requires feedback to the engine control system in order to adjust the quantity, timing, and placement of fuel charges. To be fully effective, sensors must be integrated into each engine in a manner that will allow continuous combustion monitoring (turbine engines) or monitoring of each discrete combustion event (diesel and SI engines). To date, the sensors available for detection of combustion events and processes have suffered from one or more of three problems: 1) Low sensitivity: The sensors are unable to provide and adequate signal-to-noise ratio in the high temperature and electrically noisy environment of the engine compartment. Attempts to overcome this difficulty have focused on heat removal and/or temperature compensation or more challenging high temperature electronics. 2) Low reliability: Sensors and/or sensor packages have been unable to withstand the engine environment for extended periods of time. Issues have included gross degradation and more subtle issues such as migration of dopants in semiconductor sensor materials. 3) High cost: The materials that have been used, the package concepts employed, and the required support electronics have all contributed to the high cost of the few sensor systems available. Prices have remained high due to the limited demand associated with the poor reliability and the high price itself. Ternary titanium nickel alloys, with platinum group metal substitution for the nickel, are deposited as thin films on MEMS-based diaphragms and patterned to form strain gages of a standard metal film configuration. The strain induced phase transformation of the SMA is used as a natural signal enhancement. These sensors are maintained at a temperature just in excess of the austenite finish temperature (Af). When the diaphragm is deformed by an applied pressure, the film undergoes the reversible martensite phase transformation. The fraction of the austenite transformed to martensite is a fraction of the applied pressure. The large difference in the resistivity of the two phases results in a very sensitive strain gage, and hence a pressure sensor with a very high gage factor. The combination of the thin film and the fact that the transformation is strain induced (rather than thermally induced) results in a sensor with very high response rate. In fact, the response rate of the sensor has been shown to be strictly a function of the mechanical response of the diaphragm. Unlike other sensor systems, the temperature of the SMA sensor is controlled above the temperature of the local environment. By controlling above the temperature of the environment, the sensor is largely immune to temperature fluctuations that can affect the response of other sensors. This technology has been demonstrated for a variety of target temperature regimes and a variety of pressure regimes. Sensor design and testing to date has ranged from 180C to >500C and design pressures of 50 to 3500 psi, with higher pressures achievable. Characterization has included analysis of the response rate, the temperature sensitivity, reliability, and the effect of gross alloy changes. Sensor performance has also been evaluated in a diesel engine test cell. Ongoing work includes the sensitivity to minor composition changes, sensitivity to film thickness, and extended reliability and engine testing.

Spark ignition timing control system for internal combustion engine with feature of suppression of jerking during engine acceleration

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

Tomisawa, N.

1989-07-04

This patent describes a spark ignition timing control system for an internal combustion engine, it comprises: sensor means monitoring preselected parameters for producing a sensor signal; first means for deriving a spark ignition timing on the basis of data contained in the sensor signal; second means for detecting an engine acceleration demand for producing an accelerating condition indicative signal; and third means, responsive to the accelerating condition indicative signal, for modifying the spark ignition timing derived by the first means after expiration of a first predetermined period of time of occurence of the accelerating condition indicative signal, in such amore » manner that the spark ignition timing is advanced and retarded for suppressing cycle-to-cycle fluctuation of engine speed and for smoothly increasing engine speed.« less

Heterogeneous collaborative sensor network for electrical management of an automated house with PV energy.

PubMed

Castillo-Cagigal, Manuel; Matallanas, Eduardo; Gutiérrez, Alvaro; Monasterio-Huelin, Félix; Caamaño-Martín, Estefaná; Masa-Bote, Daniel; Jiménez-Leube, Javier

2011-01-01

In this paper we present a heterogeneous collaborative sensor network for electrical management in the residential sector. Improving demand-side management is very important in distributed energy generation applications. Sensing and control are the foundations of the "Smart Grid" which is the future of large-scale energy management. The system presented in this paper has been developed on a self-sufficient solar house called "MagicBox" equipped with grid connection, PV generation, lead-acid batteries, controllable appliances and smart metering. Therefore, there is a large number of energy variables to be monitored that allow us to precisely manage the energy performance of the house by means of collaborative sensors. The experimental results, performed on a real house, demonstrate the feasibility of the proposed collaborative system to reduce the consumption of electrical power and to increase energy efficiency.

Minimalistic optic flow sensors applied to indoor and outdoor visual guidance and odometry on a car-like robot.

PubMed

Mafrica, Stefano; Servel, Alain; Ruffier, Franck

2016-11-10

Here we present a novel bio-inspired optic flow (OF) sensor and its application to visual  guidance and odometry on a low-cost car-like robot called BioCarBot. The minimalistic OF sensor was robust to high-dynamic-range lighting conditions and to various visual patterns encountered thanks to its M 2 APIX auto-adaptive pixels and the new cross-correlation OF algorithm implemented. The low-cost car-like robot estimated its velocity and steering angle, and therefore its position and orientation, via an extended Kalman filter (EKF) using only two downward-facing OF sensors and the Ackerman steering model. Indoor and outdoor experiments were carried out in which the robot was driven in the closed-loop mode based on the velocity and steering angle estimates. The experimental results obtained show that our novel OF sensor can deliver high-frequency measurements ([Formula: see text]) in a wide OF range (1.5-[Formula: see text]) and in a 7-decade high-dynamic light level range. The OF resolution was constant and could be adjusted as required (up to [Formula: see text]), and the OF precision obtained was relatively high (standard deviation of [Formula: see text] with an average OF of [Formula: see text], under the most demanding lighting conditions). An EKF-based algorithm gave the robot's position and orientation with a relatively high accuracy (maximum errors outdoors at a very low light level: [Formula: see text] and [Formula: see text] over about [Formula: see text] and [Formula: see text]) despite the low-resolution control systems of the steering servo and the DC motor, as well as a simplified model identification and calibration. Finally, the minimalistic OF-based odometry results were compared to those obtained using measurements based on an inertial measurement unit (IMU) and a motor's speed sensor.

Conformal self-assembled thin films for optical pH sensors

NASA Astrophysics Data System (ADS)

Topasna, Daniela M.; Topasna, Gregory A.; Liu, Minghanbo; Tseng, Ching-Hung

2016-04-01

Simple, reliable, lightweight, and inexpensive thin films based sensors are still in intense development and high demand in many applications such as biomedical, industrial, environmental, military, and consumer products. One important class of sensors is the optical pH sensor. In addition, conformal thin film based sensors extend the range of application for pH optical sensors. We present the results on the fabrication and characterization of optical pH sensing coatings made through ionic self-assembled technique. These thin films are based on the combination of a polyelectrolyte and water-soluble organic dye molecule Direct Yellow 4. A series of films was fabricated and characterized in order to determine the optimized parameters of the polymer and of the organic dye solutions. The optical pH responses of these films were also studied. The transparent films were immersed in solutions at various temperature and pH values. The films are stable when immersed in solutions with pH below 9.0 and temperatures below 90 °C and they maintain their performance after longer immersion times. We also demonstrate the functionality of these coatings as conformal films.

Multifuctional integrated sensors (MFISES).

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

Homeijer, Brian D.; Roozeboom, Clifton

2015-10-01

Many emerging IoT applications require sensing of multiple physical and environmental parameters for: completeness of information, measurement validation, unexpected demands, improved performance. For example, a typical outdoor weather station measures temperature, humidity, barometric pressure, light intensity, rainfall, wind speed and direction. Existing sensor technologies do not directly address the demand for cost, size, and power reduction in multi-paramater sensing applications. Industry sensor manufacturers have developed integrated sensor systems for inertial measurements that combine accelerometers, gyroscopes, and magnetometers, but do not address environmental sensing functionality. In existing research literature, a technology gap exists between the functionality of MEMS sensors and themore » real world applications of the sensors systems.« less

Mathematical models and photogrammetric exploitation of image sensing

NASA Astrophysics Data System (ADS)

Puatanachokchai, Chokchai

Mathematical models of image sensing are generally categorized into physical/geometrical sensor models and replacement sensor models. While the former is determined from image sensing geometry, the latter is based on knowledge of the physical/geometric sensor models and on using such models for its implementation. The main thrust of this research is in replacement sensor models which have three important characteristics: (1) Highly accurate ground-to-image functions; (2) Rigorous error propagation that is essentially of the same accuracy as the physical model; and, (3) Adjustability, or the ability to upgrade the replacement sensor model parameters when additional control information becomes available after the replacement sensor model has replaced the physical model. In this research, such replacement sensor models are considered as True Replacement Models or TRMs. TRMs provide a significant advantage of universality, particularly for image exploitation functions. There have been several writings about replacement sensor models, and except for the so called RSM (Replacement Sensor Model as a product described in the Manual of Photogrammetry), almost all of them pay very little or no attention to errors and their propagation. This is because, it is suspected, the few physical sensor parameters are usually replaced by many more parameters, thus presenting a potential error estimation difficulty. The third characteristic, adjustability, is perhaps the most demanding. It provides an equivalent flexibility to that of triangulation using the physical model. Primary contributions of this thesis include not only "the eigen-approach", a novel means of replacing the original sensor parameter covariance matrices at the time of estimating the TRM, but also the implementation of the hybrid approach that combines the eigen-approach with the added parameters approach used in the RSM. Using either the eigen-approach or the hybrid approach, rigorous error propagation can be performed during image exploitation. Further, adjustability can be performed when additional control information becomes available after the TRM has been implemented. The TRM is shown to apply to imagery from sensors having different geometries, including an aerial frame camera, a spaceborne linear array sensor, an airborne pushbroom sensor, and an airborne whiskbroom sensor. TRM results show essentially negligible differences as compared to those from rigorous physical sensor models, both for geopositioning from single and overlapping images. Simulated as well as real image data are used to address all three characteristics of the TRM.

Direct-write nanoscale printing of nanogranular tunnelling strain sensors for sub-micrometre cantilevers

PubMed Central

Dukic, Maja; Winhold, Marcel; Schwalb, Christian H.; Adams, Jonathan D.; Stavrov, Vladimir; Huth, Michael; Fantner, Georg E.

2016-01-01

The sensitivity and detection speed of cantilever-based mechanical sensors increases drastically through size reduction. The need for such increased performance for high-speed nanocharacterization and bio-sensing, drives their sub-micrometre miniaturization in a variety of research fields. However, existing detection methods of the cantilever motion do not scale down easily, prohibiting further increase in the sensitivity and detection speed. Here we report a nanomechanical sensor readout based on electron co-tunnelling through a nanogranular metal. The sensors can be deposited with lateral dimensions down to tens of nm, allowing the readout of nanoscale cantilevers without constraints on their size, geometry or material. By modifying the inter-granular tunnel-coupling strength, the sensors' conductivity can be tuned by up to four orders of magnitude, to optimize their performance. We show that the nanoscale printed sensors are functional on 500 nm wide cantilevers and that their sensitivity is suited even for demanding applications such as atomic force microscopy. PMID:27666316

CMOS Cell Sensors for Point-of-Care Diagnostics

PubMed Central

Adiguzel, Yekbun; Kulah, Haluk

2012-01-01

The burden of health-care related services in a global era with continuously increasing population and inefficient dissipation of the resources requires effective solutions. From this perspective, point-of-care diagnostics is a demanded field in clinics. It is also necessary both for prompt diagnosis and for providing health services evenly throughout the population, including the rural districts. The requirements can only be fulfilled by technologies whose productivity has already been proven, such as complementary metal-oxide-semiconductors (CMOS). CMOS-based products can enable clinical tests in a fast, simple, safe, and reliable manner, with improved sensitivities. Portability due to diminished sensor dimensions and compactness of the test set-ups, along with low sample and power consumption, is another vital feature. CMOS-based sensors for cell studies have the potential to become essential counterparts of point-of-care diagnostics technologies. Hence, this review attempts to inform on the sensors fabricated with CMOS technology for point-of-care diagnostic studies, with a focus on CMOS image sensors and capacitance sensors for cell studies. PMID:23112587

CMOS cell sensors for point-of-care diagnostics.

PubMed

Adiguzel, Yekbun; Kulah, Haluk

2012-01-01

The burden of health-care related services in a global era with continuously increasing population and inefficient dissipation of the resources requires effective solutions. From this perspective, point-of-care diagnostics is a demanded field in clinics. It is also necessary both for prompt diagnosis and for providing health services evenly throughout the population, including the rural districts. The requirements can only be fulfilled by technologies whose productivity has already been proven, such as complementary metal-oxide-semiconductors (CMOS). CMOS-based products can enable clinical tests in a fast, simple, safe, and reliable manner, with improved sensitivities. Portability due to diminished sensor dimensions and compactness of the test set-ups, along with low sample and power consumption, is another vital feature. CMOS-based sensors for cell studies have the potential to become essential counterparts of point-of-care diagnostics technologies. Hence, this review attempts to inform on the sensors fabricated with CMOS technology for point-of-care diagnostic studies, with a focus on CMOS image sensors and capacitance sensors for cell studies.

Sensor Webs with a Service-Oriented Architecture for On-demand Science Products

NASA Technical Reports Server (NTRS)

Mandl, Daniel; Ungar, Stephen; Ames, Troy; Justice, Chris; Frye, Stuart; Chien, Steve; Tran, Daniel; Cappelaere, Patrice; Derezinsfi, Linda; Paules, Granville;

A Large Area Tactile Sensor Patch Based on Commercial Force Sensors

PubMed Central

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

2011-01-01

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

An Embedded Stress Sensor for Concrete SHM Based on Amorphous Ferromagnetic Microwires

PubMed Central

Olivera, Jesús; González, Margarita; Fuente, José Vicente; Varga, Rastislav; Zhukov, Arkady; Anaya, José Javier

2014-01-01

A new smart concrete aggregate design as a candidate for applications in structural health monitoring (SHM) of critical elements in civil infrastructure is proposed. The cement-based stress/strain sensor was developed by utilizing the stress/strain sensing properties of a magnetic microwire embedded in cement-based composite (MMCC). This is a contact-less type sensor that measures variations of magnetic properties resulting from stress variations. Sensors made of these materials can be designed to satisfy the specific demand for an economic way to monitor concrete infrastructure health. For this purpose, we embedded a thin magnetic microwire in the core of a cement-based cylinder, which was inserted into the concrete specimen under study as an extra aggregate. The experimental results show that the embedded MMCC sensor is capable of measuring internal compressive stress around the range of 1–30 MPa. Two stress sensing properties of the embedded sensor under uniaxial compression were studied: the peak amplitude and peak position of magnetic switching field. The sensitivity values for the amplitude and position within the measured range were 5 mV/MPa and 2.5 μs/MPa, respectively. PMID:25347582

Note: Reliable and non-contact 6D motion tracking system based on 2D laser scanners for cargo transportation.

PubMed

Kim, Young-Keun; Kim, Kyung-Soo

2014-10-01

Maritime transportation demands an accurate measurement system to track the motion of oscillating container boxes in real time. However, it is a challenge to design a sensor system that can provide both reliable and non-contact methods of 6-DOF motion measurements of a remote object for outdoor applications. In the paper, a sensor system based on two 2D laser scanners is proposed for detecting the relative 6-DOF motion of a crane load in real time. Even without implementing a camera, the proposed system can detect the motion of a remote object using four laser beam points. Because it is a laser-based sensor, the system is expected to be highly robust to sea weather conditions.

Note: Reliable and non-contact 6D motion tracking system based on 2D laser scanners for cargo transportation

NASA Astrophysics Data System (ADS)

Kim, Young-Keun; Kim, Kyung-Soo

2014-10-01

Maritime transportation demands an accurate measurement system to track the motion of oscillating container boxes in real time. However, it is a challenge to design a sensor system that can provide both reliable and non-contact methods of 6-DOF motion measurements of a remote object for outdoor applications. In the paper, a sensor system based on two 2D laser scanners is proposed for detecting the relative 6-DOF motion of a crane load in real time. Even without implementing a camera, the proposed system can detect the motion of a remote object using four laser beam points. Because it is a laser-based sensor, the system is expected to be highly robust to sea weather conditions.

Rule-based fault diagnosis of hall sensors and fault-tolerant control of PMSM

NASA Astrophysics Data System (ADS)

Song, Ziyou; Li, Jianqiu; Ouyang, Minggao; Gu, Jing; Feng, Xuning; Lu, Dongbin

2013-07-01

Hall sensor is widely used for estimating rotor phase of permanent magnet synchronous motor(PMSM). And rotor position is an essential parameter of PMSM control algorithm, hence it is very dangerous if Hall senor faults occur. But there is scarcely any research focusing on fault diagnosis and fault-tolerant control of Hall sensor used in PMSM. From this standpoint, the Hall sensor faults which may occur during the PMSM operating are theoretically analyzed. According to the analysis results, the fault diagnosis algorithm of Hall sensor, which is based on three rules, is proposed to classify the fault phenomena accurately. The rotor phase estimation algorithms, based on one or two Hall sensor(s), are initialized to engender the fault-tolerant control algorithm. The fault diagnosis algorithm can detect 60 Hall fault phenomena in total as well as all detections can be fulfilled in 1/138 rotor rotation period. The fault-tolerant control algorithm can achieve a smooth torque production which means the same control effect as normal control mode (with three Hall sensors). Finally, the PMSM bench test verifies the accuracy and rapidity of fault diagnosis and fault-tolerant control strategies. The fault diagnosis algorithm can detect all Hall sensor faults promptly and fault-tolerant control algorithm allows the PMSM to face failure conditions of one or two Hall sensor(s). In addition, the transitions between health-control and fault-tolerant control conditions are smooth without any additional noise and harshness. Proposed algorithms can deal with the Hall sensor faults of PMSM in real applications, and can be provided to realize the fault diagnosis and fault-tolerant control of PMSM.

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.

Development of hardware system using temperature and vibration maintenance models integration concepts for conventional machines monitoring: a case study

NASA Astrophysics Data System (ADS)

Adeyeri, Michael Kanisuru; Mpofu, Khumbulani; Kareem, Buliaminu

2016-03-01

This article describes the integration of temperature and vibration models for maintenance monitoring of conventional machinery parts in which their optimal and best functionalities are affected by abnormal changes in temperature and vibration values thereby resulting in machine failures, machines breakdown, poor quality of products, inability to meeting customers' demand, poor inventory control and just to mention a few. The work entails the use of temperature and vibration sensors as monitoring probes programmed in microcontroller using C language. The developed hardware consists of vibration sensor of ADXL345, temperature sensor of AD594/595 of type K thermocouple, microcontroller, graphic liquid crystal display, real time clock, etc. The hardware is divided into two: one is based at the workstation (majorly meant to monitor machines behaviour) and the other at the base station (meant to receive transmission of machines information sent from the workstation), working cooperatively for effective functionalities. The resulting hardware built was calibrated, tested using model verification and validated through principles pivoted on least square and regression analysis approach using data read from the gear boxes of extruding and cutting machines used for polyethylene bag production. The results got therein confirmed related correlation existing between time, vibration and temperature, which are reflections of effective formulation of the developed concept.

Root Zone Sensors for Irrigation Management in Intensive Agriculture

PubMed Central

Pardossi, Alberto; Incrocci, Luca; Incrocci, Giorgio; Malorgio, Fernando; Battista, Piero; Bacci, Laura; Rapi, Bernardo; Marzialetti, Paolo; Hemming, Jochen; Balendonck, Jos

2009-01-01

Crop irrigation uses more than 70% of the world’s water, and thus, improving irrigation efficiency is decisive to sustain the food demand from a fast-growing world population. This objective may be accomplished by cultivating more water-efficient crop species and/or through the application of efficient irrigation systems, which includes the implementation of a suitable method for precise scheduling. At the farm level, irrigation is generally scheduled based on the grower’s experience or on the determination of soil water balance (weather-based method). An alternative approach entails the measurement of soil water status. Expensive and sophisticated root zone sensors (RZS), such as neutron probes, are available for the use of soil and plant scientists, while cheap and practical devices are needed for irrigation management in commercial crops. The paper illustrates the main features of RZS’ (for both soil moisture and salinity) marketed for the irrigation industry and discusses how such sensors may be integrated in a wireless network for computer-controlled irrigation and used for innovative irrigation strategies, such as deficit or dual-water irrigation. The paper also consider the main results of recent or current research works conducted by the authors in Tuscany (Italy) on the irrigation management of container-grown ornamental plants, which is an important agricultural sector in Italy. PMID:22574047

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.

Network-based production quality control

NASA Astrophysics Data System (ADS)

Kwon, Yongjin; Tseng, Bill; Chiou, Richard

2007-09-01

This study investigates the feasibility of remote quality control using a host of advanced automation equipment with Internet accessibility. Recent emphasis on product quality and reduction of waste stems from the dynamic, globalized and customer-driven market, which brings opportunities and threats to companies, depending on the response speed and production strategies. The current trends in industry also include a wide spread of distributed manufacturing systems, where design, production, and management facilities are geographically dispersed. This situation mandates not only the accessibility to remotely located production equipment for monitoring and control, but efficient means of responding to changing environment to counter process variations and diverse customer demands. To compete under such an environment, companies are striving to achieve 100%, sensor-based, automated inspection for zero-defect manufacturing. In this study, the Internet-based quality control scheme is referred to as "E-Quality for Manufacturing" or "EQM" for short. By its definition, EQM refers to a holistic approach to design and to embed efficient quality control functions in the context of network integrated manufacturing systems. Such system let designers located far away from the production facility to monitor, control and adjust the quality inspection processes as production design evolves.

[Exoskeleton robot system based on real-time gait analysis for walking assist].

PubMed

Xie, Zheng; Wang, Mingjiang; Huang, Wulong; Yong, Shanshan; Wang, Xin'an

2017-04-01

This paper presents a wearable exoskeleton robot system to realize walking assist function, which oriented toward the patients or the elderly with the mild impairment of leg movement function, due to illness or natural aging. It reduces the loads of hip, knee, ankle and leg muscles during walking by way of weight support. In consideration of the characteristics of the psychological demands and the disease, unlike the weight loss system in the fixed or followed rehabilitation robot, the structure of the proposed exoskeleton robot is artistic, lightweight and portable. The exoskeleton system analyzes the user's gait real-timely by the plantar pressure sensors to divide gait phases, and present different control strategies for each gait phase. The pressure sensors in the seat of the exoskeleton system provide real-time monitoring of the support efforts. And the drive control uses proportion-integral-derivative (PID) control technology for torque control. The total weight of the robot system is about 12.5 kg. The average of the auxiliary support is about 10 kg during standing, and it is about 3 kg during walking. The system showed, in the experiments, a certain effect of weight support, and reduction of the pressure on the lower limbs to walk and stand.

A Prototype Land Information Sensor Web: Design, Implementation and Implication for the SMAP Mission

NASA Astrophysics Data System (ADS)

Su, H.; Houser, P.; Tian, Y.; Geiger, J. K.; Kumar, S. V.; Gates, L.

2009-12-01

Land Surface Model (LSM) predictions are regular in time and space, but these predictions are influenced by errors in model structure, input variables, parameters and inadequate treatment of sub-grid scale spatial variability. Consequently, LSM predictions are significantly improved through observation constraints made in a data assimilation framework. Several multi-sensor satellites are currently operating which provide multiple global observations of the land surface, and its related near-atmospheric properties. However, these observations are not optimal for addressing current and future land surface environmental problems. To meet future earth system science challenges, NASA will develop constellations of smart satellites in sensor web configurations which provide timely on-demand data and analysis to users, and can be reconfigured based on the changing needs of science and available technology. A sensor web is more than a collection of satellite sensors. That means a sensor web is a system composed of multiple platforms interconnected by a communication network for the purpose of performing specific observations and processing data required to support specific science goals. Sensor webs can eclipse the value of disparate sensor components by reducing response time and increasing scientific value, especially when the two-way interaction between the model and the sensor web is enabled. The study of a prototype Land Information Sensor Web (LISW) is sponsored by NASA, trying to integrate the Land Information System (LIS) in a sensor web framework which allows for optimal 2-way information flow that enhances land surface modeling using sensor web observations, and in turn allows sensor web reconfiguration to minimize overall system uncertainty. This prototype is based on a simulated interactive sensor web, which is then used to exercise and optimize the sensor web modeling interfaces. The Land Information Sensor Web Service-Oriented Architecture (LISW-SOA) has been developed and it is the very first sensor web framework developed especially for the land surface studies. Synthetic experiments based on the LISW-SOA and the virtual sensor web provide a controlled environment in which to examine the end-to-end performance of the prototype, the impact of various sensor web design trade-offs and the eventual value of sensor webs for a particular prediction or decision support. In this paper, the design, implementation of the LISW-SOA and the implication for the Soil Moisture Active and Passive (SMAP) mission is presented. Particular attention is focused on examining the relationship between the economic investment on a sensor web (space and air borne, ground based) and the accuracy of the model predicted soil moisture, which can be achieved by using such sensor observations. The Study of Virtual Land Information Sensor Web (LISW) is expected to provide some necessary a priori knowledge for designing and deploying the next generation Global Earth Observing System of systems (GEOSS).

Suitability of Smartphone Inertial Sensors for Real-Time Biofeedback Applications.

PubMed

Kos, Anton; Tomažič, Sašo; Umek, Anton

2016-02-27

This article studies the suitability of smartphones with built-in inertial sensors for biofeedback applications. Biofeedback systems use various sensors to measure body functions and parameters. These sensor data are analyzed, and the results are communicated back to the user, who then tries to act on the feedback signals. Smartphone inertial sensors can be used to capture body movements in biomechanical biofeedback systems. These sensors exhibit various inaccuracies that induce significant angular and positional errors. We studied deterministic and random errors of smartphone accelerometers and gyroscopes, primarily focusing on their biases. Based on extensive measurements, we determined accelerometer and gyroscope noise models and bias variation ranges. Then, we compiled a table of predicted positional and angular errors under various biofeedback system operation conditions. We suggest several bias compensation options that are suitable for various examples of use in real-time biofeedback applications. Measurements within the developed experimental biofeedback application show that under certain conditions, even uncompensated sensors can be used for real-time biofeedback. For general use, especially for more demanding biofeedback applications, sensor biases should be compensated. We are convinced that real-time biofeedback systems based on smartphone inertial sensors are applicable to many similar examples in sports, healthcare, and other areas.

Suitability of Smartphone Inertial Sensors for Real-Time Biofeedback Applications

PubMed Central

Kos, Anton; Tomažič, Sašo; Umek, Anton

2016-01-01

This article studies the suitability of smartphones with built-in inertial sensors for biofeedback applications. Biofeedback systems use various sensors to measure body functions and parameters. These sensor data are analyzed, and the results are communicated back to the user, who then tries to act on the feedback signals. Smartphone inertial sensors can be used to capture body movements in biomechanical biofeedback systems. These sensors exhibit various inaccuracies that induce significant angular and positional errors. We studied deterministic and random errors of smartphone accelerometers and gyroscopes, primarily focusing on their biases. Based on extensive measurements, we determined accelerometer and gyroscope noise models and bias variation ranges. Then, we compiled a table of predicted positional and angular errors under various biofeedback system operation conditions. We suggest several bias compensation options that are suitable for various examples of use in real-time biofeedback applications. Measurements within the developed experimental biofeedback application show that under certain conditions, even uncompensated sensors can be used for real-time biofeedback. For general use, especially for more demanding biofeedback applications, sensor biases should be compensated. We are convinced that real-time biofeedback systems based on smartphone inertial sensors are applicable to many similar examples in sports, healthcare, and other areas. PMID:26927125

Low cost attitude control system scanwheel development

NASA Astrophysics Data System (ADS)

Bialke, William; Selby, Vaughn

1991-03-01

In order to satisfy a growing demand for low cost attitude control systems for small spacecraft, development of low cost scanning horizon sensor coupled to a low cost/low power consumption Reaction Wheel Assembly was initiated. This report addresses the details of the versatile design resulting from this effort. Tradeoff analyses for each of the major components are included, as well as test data from an engineering prototype of the hardware.

Low cost attitude control system scanwheel development

NASA Technical Reports Server (NTRS)

Bialke, William; Selby, Vaughn

1991-01-01

In order to satisfy a growing demand for low cost attitude control systems for small spacecraft, development of low cost scanning horizon sensor coupled to a low cost/low power consumption Reaction Wheel Assembly was initiated. This report addresses the details of the versatile design resulting from this effort. Tradeoff analyses for each of the major components are included, as well as test data from an engineering prototype of the hardware.

A Low-Power Wireless Image Sensor Node with Noise-Robust Moving Object Detection and a Region-of-Interest Based Rate Controller

DTIC Science & Technology

2017-03-01

A Low- Power Wireless Image Sensor Node with Noise-Robust Moving Object Detection and a Region-of-Interest Based Rate Controller Jong Hwan Ko...Atlanta, GA 30332 USA Contact Author Email: jonghwan.ko@gatech.edu Abstract: This paper presents a low- power wireless image sensor node for...present a low- power wireless image sensor node with a noise-robust moving object detection and region-of-interest based rate controller [Fig. 1]. The

Secure, Autonomous, Intelligent Controller for Integrating Distributed Sensor Webs

NASA Technical Reports Server (NTRS)

Ivancic, William D.

2007-01-01

This paper describes the infrastructure and protocols necessary to enable near-real-time commanding, access to space-based assets, and the secure interoperation between sensor webs owned and controlled by various entities. Select terrestrial and aeronautics-base sensor webs will be used to demonstrate time-critical interoperability between integrated, intelligent sensor webs both terrestrial and between terrestrial and space-based assets. For this work, a Secure, Autonomous, Intelligent Controller and knowledge generation unit is implemented using Virtual Mission Operation Center technology.

Low Power Operation of Temperature-Modulated Metal Oxide Semiconductor Gas Sensors.

PubMed

Burgués, Javier; Marco, Santiago

2018-01-25

Mobile applications based on gas sensing present new opportunities for low-cost air quality monitoring, safety, and healthcare. Metal oxide semiconductor (MOX) gas sensors represent the most prominent technology for integration into portable devices, such as smartphones and wearables. Traditionally, MOX sensors have been continuously powered to increase the stability of the sensing layer. However, continuous power is not feasible in many battery-operated applications due to power consumption limitations or the intended intermittent device operation. This work benchmarks two low-power, duty-cycling, and on-demand modes against the continuous power one. The duty-cycling mode periodically turns the sensors on and off and represents a trade-off between power consumption and stability. On-demand operation achieves the lowest power consumption by powering the sensors only while taking a measurement. Twelve thermally modulated SB-500-12 (FIS Inc. Jacksonville, FL, USA) sensors were exposed to low concentrations of carbon monoxide (0-9 ppm) with environmental conditions, such as ambient humidity (15-75% relative humidity) and temperature (21-27 °C), varying within the indicated ranges. Partial Least Squares (PLS) models were built using calibration data, and the prediction error in external validation samples was evaluated during the two weeks following calibration. We found that on-demand operation produced a deformation of the sensor conductance patterns, which led to an increase in the prediction error by almost a factor of 5 as compared to continuous operation (2.2 versus 0.45 ppm). Applying a 10% duty-cycling operation of 10-min periods reduced this prediction error to a factor of 2 (0.9 versus 0.45 ppm). The proposed duty-cycling powering scheme saved up to 90% energy as compared to the continuous operating mode. This low-power mode may be advantageous for applications that do not require continuous and periodic measurements, and which can tolerate slightly higher prediction errors.

Protecting muscle ATP: positive roles for peripheral defense mechanisms-introduction.

PubMed

Myburgh, Kathryn H

2004-01-01

Skeletal muscle has evolved an impressive array of mechanisms for peripherally mediated control of ATP homeostasis. Some of these mechanisms are intracellular, and others are extracellular and include influences on the cross-bridge cycle itself and substrate supply. This paper introduces three distinctly different topics that nevertheless all have ATP defense in common. The role of ADP in fatigue is controversial but has recently been more clearly delineated so that an effect on alleviating force declines during extreme fatigue is plausible. AMP plays its role by activating the protein-kinase, AMPK, which is a key sensor of cellular energy stress. AMPK has different isoforms, is not uniformly distributed in the cell, and its activation is carefully controlled. It has multiple effects including improvements in substrate supply for the metabolic pathways producing ATP and inhibition of anabolic processes to further spare ATP. Red blood cells have the capacity to sense hypoxia and to release vasodilators where there is a locally increased demand for blood supply. The papers in this series emphasize the important positive roles of metabolites and sensors of fatigue in the balance between ATP supply and demand.

Ion-Specific Nutrient Management in Closed Systems: The Necessity for Ion-Selective Sensors in Terrestrial and Space-Based Agriculture and Water Management Systems

PubMed Central

Bamsey, Matthew; Graham, Thomas; Thompson, Cody; Berinstain, Alain; Scott, Alan; Dixon, Michael

2012-01-01

The ability to monitor and control plant nutrient ions in fertigation solutions, on an ion-specific basis, is critical to the future of controlled environment agriculture crop production, be it in traditional terrestrial settings (e.g., greenhouse crop production) or as a component of bioregenerative life support systems for long duration space exploration. Several technologies are currently available that can provide the required measurement of ion-specific activities in solution. The greenhouse sector has invested in research examining the potential of a number of these technologies to meet the industry's demanding requirements, and although no ideal solution yet exists for on-line measurement, growers do utilize technologies such as high-performance liquid chromatography to provide off-line measurements. An analogous situation exists on the International Space Station where, technological solutions are sought, but currently on-orbit water quality monitoring is considerably restricted. This paper examines the specific advantages that on-line ion-selective sensors could provide to plant production systems both terrestrially and when utilized in space-based biological life support systems and how similar technologies could be applied to nominal on-orbit water quality monitoring. A historical development and technical review of the various ion-selective monitoring technologies is provided. PMID:23201999

Ion-specific nutrient management in closed systems: the necessity for ion-selective sensors in terrestrial and space-based agriculture and water management systems.

PubMed

Bamsey, Matthew; Graham, Thomas; Thompson, Cody; Berinstain, Alain; Scott, Alan; Dixon, Michael

2012-10-01

The ability to monitor and control plant nutrient ions in fertigation solutions, on an ion-specific basis, is critical to the future of controlled environment agriculture crop production, be it in traditional terrestrial settings (e.g., greenhouse crop production) or as a component of bioregenerative life support systems for long duration space exploration. Several technologies are currently available that can provide the required measurement of ion-specific activities in solution. The greenhouse sector has invested in research examining the potential of a number of these technologies to meet the industry's demanding requirements, and although no ideal solution yet exists for on-line measurement, growers do utilize technologies such as high-performance liquid chromatography to provide off-line measurements. An analogous situation exists on the International Space Station where, technological solutions are sought, but currently on-orbit water quality monitoring is considerably restricted. This paper examines the specific advantages that on-line ion-selective sensors could provide to plant production systems both terrestrially and when utilized in space-based biological life support systems and how similar technologies could be applied to nominal on-orbit water quality monitoring. A historical development and technical review of the various ion-selective monitoring technologies is provided.

Heterogeneous Collaborative Sensor Network for Electrical Management of an Automated House with PV Energy

PubMed Central

Castillo-Cagigal, Manuel; Matallanas, Eduardo; Gutiérrez, Álvaro; Monasterio-Huelin, Félix; Caamaño-Martín, Estefaná; Masa-Bote, Daniel; Jiménez-Leube, Javier

2011-01-01

In this paper we present a heterogeneous collaborative sensor network for electrical management in the residential sector. Improving demand-side management is very important in distributed energy generation applications. Sensing and control are the foundations of the “Smart Grid” which is the future of large-scale energy management. The system presented in this paper has been developed on a self-sufficient solar house called “MagicBox” equipped with grid connection, PV generation, lead-acid batteries, controllable appliances and smart metering. Therefore, there is a large number of energy variables to be monitored that allow us to precisely manage the energy performance of the house by means of collaborative sensors. The experimental results, performed on a real house, demonstrate the feasibility of the proposed collaborative system to reduce the consumption of electrical power and to increase energy efficiency. PMID:22247680

Design and Test of a Soil Profile Moisture Sensor Based on Sensitive Soil Layers.

PubMed

Gao, Zhenran; Zhu, Yan; Liu, Cheng; Qian, Hongzhou; Cao, Weixing; Ni, Jun

2018-05-21

To meet the demand of intelligent irrigation for accurate moisture sensing in the soil vertical profile, a soil profile moisture sensor was designed based on the principle of high-frequency capacitance. The sensor consists of five groups of sensing probes, a data processor, and some accessory components. Low-resistivity copper rings were used as components of the sensing probes. Composable simulation of the sensor’s sensing probes was carried out using a high-frequency structure simulator. According to the effective radiation range of electric field intensity, width and spacing of copper ring were set to 30 mm and 40 mm, respectively. A parallel resonance circuit of voltage-controlled oscillator and high-frequency inductance-capacitance (LC) was designed for signal frequency division and conditioning. A data processor was used to process moisture-related frequency signals for soil profile moisture sensing. The sensor was able to detect real-time soil moisture at the depths of 20, 30, and 50 cm and conduct online inversion of moisture in the soil layer between 0⁻100 cm. According to the calibration results, the degree of fitting ( R ²) between the sensor’s measuring frequency and the volumetric moisture content of soil sample was 0.99 and the relative error of the sensor consistency test was 0⁻1.17%. Field tests in different loam soils showed that measured soil moisture from our sensor reproduced the observed soil moisture dynamic well, with an R ² of 0.96 and a root mean square error of 0.04. In a sensor accuracy test, the R ² between the measured value of the proposed sensor and that of the Diviner2000 portable soil moisture monitoring system was higher than 0.85, with a relative error smaller than 5%. The R ² between measured values and inversed soil moisture values for other soil layers were consistently higher than 0.8. According to calibration test and field test, this sensor, which features low cost, good operability, and high integration, is qualified for precise agricultural irrigation with stable performance and high accuracy.

Quantum gyroscope based on Berry phase of spins in diamond

NASA Astrophysics Data System (ADS)

Song, Xuerui; Wang, Liujun; Diao, Wenting; Duan, Chongdi

2018-02-01

Gyroscope is the crucial sensor of the inertial navigation system, there is always high demand to improve the sensitivity and reduce the size of the gyroscopes. Using the NV center electronic spin and nuclear spin qubits in diamond, we introduce the research of new types of quantum gyroscopes based on the Berry phase shifts of the spin states during the rotation of the sensor systems. Compared with the performance of the traditional MEMS gyroscope, the sensitivity of the new types of quantum gyroscopes was highly improved and the spatial resolution was reduced to nano-scale. With the help of micro-manufacturing technology in the semiconductor industry, the quantum gyroscopes introduced here can be further integrated into chip-scale sensors.

Elements for successful sensor-based process control {Integrated Metrology}

NASA Astrophysics Data System (ADS)

Butler, Stephanie Watts

1998-11-01

Current productivity needs have stimulated development of alternative metrology, control, and equipment maintenance methods. Specifically, sensor applications provide the opportunity to increase productivity, tighten control, reduce scrap, and improve maintenance schedules and procedures. Past experience indicates a complete integrated solution must be provided for sensor-based control to be used successfully in production. In this paper, Integrated Metrology is proposed as the term for an integrated solution that will result in a successful application of sensors for process control. This paper defines and explores the perceived four elements of successful sensor applications: business needs, integration, components, and form. Based upon analysis of existing successful commercially available controllers, the necessary business factors have been determined to be strong, measurable industry-wide business needs whose solution is profitable and feasible. This paper examines why the key aspect of integration is the decision making process. A detailed discussion is provided of the components of most importance to sensor based control: decision-making methods, the 3R's of sensors, and connectivity. A metric for one of the R's (resolution) is proposed to allow focus on this important aspect of measurement. A form for these integrated components which synergistically partitions various aspects of control at the equipment and MES levels to efficiently achieve desired benefits is recommended.

Agent-Based Intelligent Interface for Wheelchair Movement Control

PubMed Central

Barriuso, Alberto L.; De Paz, Juan F.

2018-01-01

People who suffer from any kind of motor difficulty face serious complications to autonomously move in their daily lives. However, a growing number research projects which propose different powered wheelchairs control systems are arising. Despite of the interest of the research community in the area, there is no platform that allows an easy integration of various control methods that make use of heterogeneous sensors and computationally demanding algorithms. In this work, an architecture based on virtual organizations of agents is proposed that makes use of a flexible and scalable communication protocol that allows the deployment of embedded agents in computationally limited devices. In order to validate the proper functioning of the proposed system, it has been integrated into a conventional wheelchair and a set of alternative control interfaces have been developed and deployed, including a portable electroencephalography system, a voice interface or as specifically designed smartphone application. A set of tests were conducted to test both the platform adequacy and the accuracy and ease of use of the proposed control systems yielding positive results that can be useful in further wheelchair interfaces design and implementation. PMID:29751603

Smart Building: Decision Making Architecture for Thermal Energy Management.

PubMed

Uribe, Oscar Hernández; Martin, Juan Pablo San; Garcia-Alegre, María C; Santos, Matilde; Guinea, Domingo

2015-10-30

Smart applications of the Internet of Things are improving the performance of buildings, reducing energy demand. Local and smart networks, soft computing methodologies, machine intelligence algorithms and pervasive sensors are some of the basics of energy optimization strategies developed for the benefit of environmental sustainability and user comfort. This work presents a distributed sensor-processor-communication decision-making architecture to improve the acquisition, storage and transfer of thermal energy in buildings. The developed system is implemented in a near Zero-Energy Building (nZEB) prototype equipped with a built-in thermal solar collector, where optical properties are analysed; a low enthalpy geothermal accumulation system, segmented in different temperature zones; and an envelope that includes a dynamic thermal barrier. An intelligent control of this dynamic thermal barrier is applied to reduce the thermal energy demand (heating and cooling) caused by daily and seasonal weather variations. Simulations and experimental results are presented to highlight the nZEB thermal energy reduction.

Electrophysiological assessment of water stress in fruit-bearing woody plants.

PubMed

Ríos-Rojas, Liliana; Tapia, Franco; Gurovich, Luis A

2014-06-15

Development and evaluation of a real-time plant water stress sensor, based on the electrophysiological behavior of fruit-bearing woody plants is presented. Continuous electric potentials are measured in tree trunks for different irrigation schedules, inducing variable water stress conditions; results are discussed in relation to soil water content and micro-atmospheric evaporative demand, determined continuously by conventional sensors, correlating this information with tree electric potential measurements. Systematic and differentiable patterns of electric potentials for water-stressed and no-stressed trees in 2 fruit species are presented. Early detection and recovery dynamics of water stress conditions can also be monitored with these electrophysiology sensors, which enable continuous and non-destructive measurements for efficient irrigation scheduling throughout the year. The experiment is developed under controlled conditions, in Faraday cages located at a greenhouse area, both in Persea americana and Prunus domestica plants. Soil moisture evolution is controlled using capacitance sensors and solar radiation, temperature, relative humidity, wind intensity and direction are continuously registered with accurate weather sensors, in a micro-agrometeorological automatic station located at the experimental site. The electrophysiological sensor has two stainless steel electrodes (measuring/reference), inserted on the stem; a high precision Keithley 2701 digital multimeter is used to measure plant electrical signals; an algorithm written in MatLab(®), allows correlating the signal to environmental variables. An electric cyclic behavior is observed (circadian cycle) in the experimental plants. For non-irrigated plants, the electrical signal shows a time positive slope and then, a negative slope after restarting irrigation throughout a rather extended recovery process, before reaching a stable electrical signal with zero slope. Well-watered plants presented a continuous signal with daily maximum and a minimum EP of similar magnitude in time, with zero slope. This plant electrical behavior is proposed for the development of a sensor measuring real-time plant water status. Copyright © 2014 Elsevier GmbH. All rights reserved.

High Sensitivity, Low Power Nano Sensors and Devices for Chemical Sensing

NASA Technical Reports Server (NTRS)

Li, Jing; Powell, Dan; Getty, Stephanie; Lu, Yi-Jiang

2004-01-01

The chemical sensor market has been projected to grow to better than $40 billion dollars worldwide within the next 10 years. Some of the primary motivations to develop nanostructured chemical sensors are monitoring and control of environmental pollution; improved diagnostics for consumption; improvement in measurement precision and accuracy; and improved detection limits for Homeland security, battlefield environments, and process and quality control of industrial applications. In each of these applications, there is demand for sensitivity, selectivity and stability of environmental and biohazard detection and capture beyond what is currently commercially available. Nanotechnology offers the ability to work at the molecular level, atom by atom, to create large structures with fundamentally new molecular organization. It is essentially concerned with materials, devices, and systems whose structures and components exhibit novel and significantly improved physical, chemical and biological properties, phenomena, and process control due to their nanoscale size. One such nanotechnology-enabled chemical sensor has been developed at NASA Ames leveraging nanostructures, such as single walled carbon nanotubes (SWNTs) and metal oxide nanobelts or nanowires, as a sensing medium bridging a pair of interdigitated electrodes (IDE) realized through a silicon-based microfabrication and micromachining technique. The DE fingers are fabricated on a silicon substrate using standard photolithography and thin film metallization techniques. It is noteworthy that the fabrication techniques employed are not confined to the silicon substrate. Through spin casting and careful substrate selection (i.e. clothing, glass, polymer, etc.), additional degrees of freedom can be exploited to enhance sensitivity or to conform to unique applications. Both in-situ growth of nanostructured materials and casting of nanostructured dispersions were used to produce analogous chemical sensing devices.

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

Fisk, William J.; Sullivan, Douglas

This pilot scale study evaluated the counting accuracy of two people counting systems that could be used in demand controlled ventilation systems to provide control signals for modulating outdoor air ventilation rates. The evaluations included controlled challenges of the people counting systems using pre-planned movements of occupants through doorways and evaluations of counting accuracies when naive occupants (i.e., occupants unaware of the counting systems) passed through the entrance doors of the building or room. The two people counting systems had high counting accuracy accuracies, with errors typically less than 10percent, for typical non-demanding counting events. However, counting errors were highmore » in some highly challenging situations, such as multiple people passing simultaneously through a door. Counting errors, for at least one system, can be very high if people stand in the field of view of the sensor. Both counting system have limitations and would need to be used only at appropriate sites and where the demanding situations that led to counting errors were rare.« less

A Bluetooth-Based Device Management Platform for Smart Sensor Environment

NASA Astrophysics Data System (ADS)

Lim, Ivan Boon-Kiat; Yow, Kin Choong

In this paper, we propose the use of Bluetooth as the device management platform for the various embedded sensors and actuators in an ambient intelligent environment. We demonstrate the ease of adding Bluetooth capability to common sensor circuits (e.g. motion sensor circuit based on a pyroelectric infrared (PIR) sensor). A central logic application is proposed which controls the operation of controller devices, based on values returned by sensors via Bluetooth. The operation of devices depends on rules that are learnt from user behavior using an Elman recurrent neural network. Overall, Bluetooth has shown its potential in being used as a device management platform in an ambient intelligent environment, which allows sensors and controllers to be deployed even in locations where power sources are not readily available, by using battery power.

Assistive acting movement therapy devices with pneumatic rotary-type soft actuators.

PubMed

Wilkening, André; Baiden, David; Ivlev, Oleg

2012-12-01

Inherent compliance and assistive behavior are assumed to be essential properties for safe human-robot interaction. Rehabilitation robots demand the highest standards in this respect because the machine interacts directly with weak persons who are often sensitive to pain. Using novel soft fluidic actuators with rotary elastic chambers (REC actuators), compact, lightweight, and cost-effective therapeutic devices can be developed. This article describes modular design and control strategies for new assistive acting robotic devices for upper and lower extremities. Due to the inherent compliance and natural back-drivability of pneumatic REC actuators, these movement therapy devices provide gentle treatment, whereby the interaction forces between humans and the therapy device are estimated without the use of expensive force/torque sensors. An active model-based gravity compensation based on separated models of the robot and of the individual patient's extremity provides the basis for effective assistive control. The utilization of pneumatic actuators demands a special safety concept, which is merged with control algorithms to provide a sufficient level of safeness and to catch any possible system errors and/or emergency situations. A self-explanatory user interface allows for easy, intuitive handling. Prototypes are very comfortable for use due to several control routines that work in the background. Assistive devices have been tested extensively with several healthy persons; the knee/hip movement therapy device is now under clinical trials at the Clinic for Orthopaedics and Trauma Surgery at the Klinikum Stuttgart.

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.

An Embedded Sensor Node Microcontroller with Crypto-Processors.

PubMed

Panić, Goran; Stecklina, Oliver; Stamenković, Zoran

2016-04-27

Wireless sensor network applications range from industrial automation and control, agricultural and environmental protection, to surveillance and medicine. In most applications, data are highly sensitive and must be protected from any type of attack and abuse. Security challenges in wireless sensor networks are mainly defined by the power and computing resources of sensor devices, memory size, quality of radio channels and susceptibility to physical capture. In this article, an embedded sensor node microcontroller designed to support sensor network applications with severe security demands is presented. It features a low power 16-bitprocessor core supported by a number of hardware accelerators designed to perform complex operations required by advanced crypto algorithms. The microcontroller integrates an embedded Flash and an 8-channel 12-bit analog-to-digital converter making it a good solution for low-power sensor nodes. The article discusses the most important security topics in wireless sensor networks and presents the architecture of the proposed hardware solution. Furthermore, it gives details on the chip implementation, verification and hardware evaluation. Finally, the chip power dissipation and performance figures are estimated and analyzed.

An Embedded Sensor Node Microcontroller with Crypto-Processors

PubMed Central

Panić, Goran; Stecklina, Oliver; Stamenković, Zoran

2016-01-01

Wireless sensor network applications range from industrial automation and control, agricultural and environmental protection, to surveillance and medicine. In most applications, data are highly sensitive and must be protected from any type of attack and abuse. Security challenges in wireless sensor networks are mainly defined by the power and computing resources of sensor devices, memory size, quality of radio channels and susceptibility to physical capture. In this article, an embedded sensor node microcontroller designed to support sensor network applications with severe security demands is presented. It features a low power 16-bitprocessor core supported by a number of hardware accelerators designed to perform complex operations required by advanced crypto algorithms. The microcontroller integrates an embedded Flash and an 8-channel 12-bit analog-to-digital converter making it a good solution for low-power sensor nodes. The article discusses the most important security topics in wireless sensor networks and presents the architecture of the proposed hardware solution. Furthermore, it gives details on the chip implementation, verification and hardware evaluation. Finally, the chip power dissipation and performance figures are estimated and analyzed. PMID:27128925

The role of optical sensors in environmental applications

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

Coulter, S.L.; Klainer, S.M.; Saini, D.

1995-12-31

With the ever increasing regulations and public consciousness on pollution control there is an increasing demand for effective monitors for field use. The specifications for an effective field monitor are that it be an in situ sensor which presents real time data; that data are received without sampling or testing artifacts; and, that there is a low cost associated with running multiple tests. Fiber optic chemical sensors have been designed by FCI Environmental, Inc. which meet these specifications for the detection of hydrocarbons in air, water or soil. Recent developments at FCI Environmental in the field of optic chemical sensorsmore » include the development of a chip level waveguide sensor. With the improvements in the size and function of the sensor, which impacts the manufacturability and cost of the sensors, this new technology presents new opportunities in the fields of in situ monitoring. Current activities in the development of this technology and applications of specific solid-state immunoassay are discussed.« less

[Energy and memory efficient calculation of the accommodation demand in the artificial accommodation system].

PubMed

Nagel, J A; Beck, C; Harms, H; Stiller, P; Guth, H; Stachs, O; Bretthauer, G

2010-12-01

Presbyopia and cataract are gaining more and more importance in the ageing society. Both age-related complaints are accompanied with a loss of the eye's ability to accommodate. A new approach to restore accommodation is the Artificial Accommodation System, an autonomous micro system, which will be implanted into the capsular bag instead of a rigid intraocular lens. The Artificial Accommodation System will, depending on the actual demand for accommodation, autonomously adapt the refractive power of its integrated optical element. One possibility to measure the demand for accommodation non-intrusively is to analyse eye movements. We present an efficient algorithm, based on the CORDIC technique, to calculate the demand for accommodation from magnetic field sensor data. It can be shown that specialised algorithms significantly shorten calculation time without violating precision requirements. Additionally, a communication strategy for the wireless exchange of sensor data between the implants of the left and right eye is introduced. The strategy allows for a one-sided calculation of the demand for accommodation, resulting in an overall reduction of calculation time by 50 %. The presented methods enable autonomous microsystems, such as the Artificial Accommodation System, to save significant amounts of energy, leading to extended autonomous run-times. © Georg Thieme Verlag KG Stuttgart · New York.

Optical Fiber-Based MR-Compatible Sensors for Medical Applications: An Overview

PubMed Central

Taffoni, Fabrizio; Formica, Domenico; Saccomandi, Paola; Di Pino, Giovanni; Schena, Emiliano

2013-01-01

During last decades, Magnetic Resonance (MR)—compatible sensors based on different techniques have been developed due to growing demand for application in medicine. There are several technological solutions to design MR-compatible sensors, among them, the one based on optical fibers presents several attractive features. The high elasticity and small size allow designing miniaturized fiber optic sensors (FOS) with metrological characteristics (e.g., accuracy, sensitivity, zero drift, and frequency response) adequate for most common medical applications; the immunity from electromagnetic interference and the absence of electrical connection to the patient make FOS suitable to be used in high electromagnetic field and intrinsically safer than conventional technologies. These two features further heightened the potential role of FOS in medicine making them especially attractive for application in MRI. This paper provides an overview of MR-compatible FOS, focusing on the sensors employed for measuring physical parameters in medicine (i.e., temperature, force, torque, strain, and position). The working principles of the most promising FOS are reviewed in terms of their relevant advantages and disadvantages, together with their applications in medicine. PMID:24145918

The demand control model and circadian saliva cortisol variations in a Swedish population based sample (The PART study)

PubMed Central

Alderling, Magnus; Theorell, Töres; de la Torre, Bartolomé; Lundberg, Ingvar

2006-01-01

Background Previous studies of the relationship between job strain and blood or saliva cortisol levels have been small and based on selected occupational groups. Our aim was to examine the association between job strain and saliva cortisol levels in a population-based study in which a number of potential confounders could be adjusted for. Methods The material derives from a population-based study in Stockholm on mental health and its potential determinants. Two data collections were performed three years apart with more than 8500 subjects responding to a questionnaire in both waves. In this paper our analyses are based on 529 individuals who held a job, participated in both waves as well as in an interview linked to the second wave. They gave saliva samples at awakening, half an hour later, at lunchtime and before going to bed on a weekday in close connection with the interview. Job control and job demands were assessed from the questionnaire in the second wave. Mixed models were used to analyse the association between the demand control model and saliva cortisol. Results Women in low strain jobs (high control and low demands) had significantly lower cortisol levels half an hour after awakening than women in high strain (low control and high demands), active (high control and high demands) or passive jobs (low control and low demands). There were no significant differences between the groups during other parts of the day and furthermore there was no difference between the job strain, active and passive groups. For men, no differences were found between demand control groups. Conclusion This population-based study, on a relatively large sample, weakly support the hypothesis that the demand control model is associated with saliva cortisol concentrations. PMID:17129377

Switch on or switch off: an optical DNA sensor based on poly(p-phenylenevinylene) grafted magnetic beads.

PubMed

Srinivas, Anupama R Gulur; Peng, Hui; Barker, David; Travas-Sejdic, Jadranka

2012-05-15

There has been an enormous demand for commercial label-free DNA sensors in a diverse range of fields including pre-emptive medicine, diagnostics, environmental monitoring, and food industry. Addressing the need for sensitive, selective and facile DNA sensors, we demonstrate a novel switch on/off sensor design that utilizes sandwich hybridization between photoluminescent anionic conjugated polyelectrolyte (CPE) bound captureprobe coated onto magnetic beads, target and the signaling probe. The hybridization-readout in our sensor was monitored by either fluorescence resonance energy transfer (FRET, switch-on) or superquenching (switch-off) depending on the type of signaling probe used. Moreover recent designs that utilize beads for sensing DNA have been limited towards using electrostatic interactions or intercalation of dyes to observe FRET. To our knowledge this is the first report of a switch on/off sensor utilizing either FRET or superquenching thus providing flexibility for future development of such rapid, facile and sensitive DNA sensors. The FRET-based sensor was investigated by optimizing the reaction parameters and selectivity. A low detection limit of 240 fmol in 2 mL of SSC buffer was achieved. Copyright © 2012 Elsevier B.V. All rights reserved.

A 1 GHz Oscillator-Type Active Antenna

NASA Technical Reports Server (NTRS)

Jordan, Jennifer L.; Scardelletti, Maximilian; Ponchak, George E.

2008-01-01

Wireless sensors are desired for monitoring aircraft engines, automotive engines, industrial machinery, and many other applications. The most important requirement of sensors is that they do not interfere with the environment that they are monitoring. Therefore, wireless sensors must be small, which demands a high level of integration. Sensors that modulate an oscillator active antenna have advantages of small size, high level of integration, and lower packaging cost. Several types of oscillator active antennas have been reported. Ip et al. demonstrated a CPW line fed patch antenna with a feedback loop [1]. No degradation in performance was noticed without a ground plane. A GaAs FET was used in an amplifier/oscillator-based active antenna [2]. An oscillator based on a Cree SiC transistor was designed and characterized in [3]. This paper reports the integration of the SiC Clapp oscillator to a slotline loop antenna.

FPGA-Based Multimodal Embedded Sensor System Integrating Low- and Mid-Level Vision

PubMed Central

Botella, Guillermo; Martín H., José Antonio; Santos, Matilde; Meyer-Baese, Uwe

2011-01-01

Motion estimation is a low-level vision task that is especially relevant due to its wide range of applications in the real world. Many of the best motion estimation algorithms include some of the features that are found in mammalians, which would demand huge computational resources and therefore are not usually available in real-time. In this paper we present a novel bioinspired sensor based on the synergy between optical flow and orthogonal variant moments. The bioinspired sensor has been designed for Very Large Scale Integration (VLSI) using properties of the mammalian cortical motion pathway. This sensor combines low-level primitives (optical flow and image moments) in order to produce a mid-level vision abstraction layer. The results are described trough experiments showing the validity of the proposed system and an analysis of the computational resources and performance of the applied algorithms. PMID:22164069

Fiber sensor for non-contact estimation of vital bio-signs

NASA Astrophysics Data System (ADS)

Sirkis, Talia; Beiderman, Yevgeny; Agdarov, Sergey; Beiderman, Yafim; Zalevsky, Zeev

2017-05-01

Continuous noninvasive measurement of vital bio-signs, such as cardiopulmonary parameters, is an important tool in evaluation of the patient's physiological condition and health monitoring. On the demand of new enabling technologies, some works have been done in arterial pulse monitoring using optical fiber sensors. In this paper, we introduce a novel device based on single mode in-fibers Mach-Zehnder interferometer (MZI) to detect heartbeat, respiration and pulse wave velocity (PWV). The introduced interferometer is based on a new implanted scheme. It replaces the conventional MZI realized by inserting of discontinuities in the fiber to break the total internal reflection and scatter/collect light. The proposed fiber sensor was successfully incorporated into shirt to produce smart clothing. The measurements obtained from the smart clothing could be obtained in comfortable manner and there is no need to have an initial calibration or a direct contact between the sensor and the skin of the tested individual.

FPGA-based multimodal embedded sensor system integrating low- and mid-level vision.

PubMed

Botella, Guillermo; Martín H, José Antonio; Santos, Matilde; Meyer-Baese, Uwe

2011-01-01

Motion estimation is a low-level vision task that is especially relevant due to its wide range of applications in the real world. Many of the best motion estimation algorithms include some of the features that are found in mammalians, which would demand huge computational resources and therefore are not usually available in real-time. In this paper we present a novel bioinspired sensor based on the synergy between optical flow and orthogonal variant moments. The bioinspired sensor has been designed for Very Large Scale Integration (VLSI) using properties of the mammalian cortical motion pathway. This sensor combines low-level primitives (optical flow and image moments) in order to produce a mid-level vision abstraction layer. The results are described trough experiments showing the validity of the proposed system and an analysis of the computational resources and performance of the applied algorithms.

New soil water sensors for irrigation management

USDA-ARS?s Scientific Manuscript database

Effective irrigation management is key to obtaining the most crop production per unit of water applied and increasing production in the face of competing demands on water resources. Management methods have included calculating crop water needs based on weather station measurements, calculating soil ...

Wireless, Room Temperature Volatile Organic Compound Sensor Based on Polypyrrole Nanoparticle Immobilized Ultrahigh Frequency Radio Frequency Identification Tag.

PubMed

Jun, Jaemoon; Oh, Jungkyun; Shin, Dong Hoon; Kim, Sung Gun; Lee, Jun Seop; Kim, Wooyoung; Jang, Jyongsik

2016-12-07

Due to rapid advances in technology which have contributed to the development of portable equipment, highly sensitive and selective sensor technology is in demand. In particular, many approaches to the modification of wireless sensor systems have been studied. Wireless systems have many advantages, including unobtrusive installation, high nodal densities, low cost, and potential commercial applications. In this study, we fabricated radio frequency identification (RFID)-based wireless sensor systems using carboxyl group functionalized polypyrrole (C-PPy) nanoparticles (NPs). The C-PPy NPs were synthesized via chemical oxidation copolymerization, and then their electrical and chemical properties were characterized by a variety of methods. The sensor system was composed of an RFID reader antenna and a sensor tag made from a commercially available ultrahigh frequency RFID tag coated with C-PPy NPs. The C-PPy NPs were covalently bonded to the tag to form a passive sensor. This type of sensor can be produced at a very low cost and exhibits ultrahigh sensitivity to ammonia, detecting concentrations as low as 0.1 ppm. These sensors operated wirelessly and maintained their sensing performance as they were deformed by bending and twisting. Due to their flexibility, these sensors may be used in wearable technologies for sensing gases.

The lucky image-motion prediction for simple scene observation based soft-sensor technology

NASA Astrophysics Data System (ADS)

Li, Yan; Su, Yun; Hu, Bin

2015-08-01

High resolution is important to earth remote sensors, while the vibration of the platforms of the remote sensors is a major factor restricting high resolution imaging. The image-motion prediction and real-time compensation are key technologies to solve this problem. For the reason that the traditional autocorrelation image algorithm cannot meet the demand for the simple scene image stabilization, this paper proposes to utilize soft-sensor technology in image-motion prediction, and focus on the research of algorithm optimization in imaging image-motion prediction. Simulations results indicate that the improving lucky image-motion stabilization algorithm combining the Back Propagation Network (BP NN) and support vector machine (SVM) is the most suitable for the simple scene image stabilization. The relative error of the image-motion prediction based the soft-sensor technology is below 5%, the training computing speed of the mathematical predication model is as fast as the real-time image stabilization in aerial photography.

Carbon nanostructures as immobilization platform for DNA: A review on current progress in electrochemical DNA sensors.

PubMed

Rasheed, P Abdul; Sandhyarani, N

2017-11-15

Development of a sensitive, specific and cost-effective DNA detection method is motivated by increasing demand for the early stage diagnosis of genetic diseases. Recent developments in the design and fabrication of efficient sensor platforms based on nanostructures make the highly sensitive sensors which could indicate very low detection limit to the level of few molecules, a realistic possibility. Electrochemical detection methods are widely used in DNA diagnostics as it provide simple, accurate and inexpensive platform for DNA detection. In addition, the electrochemical DNA sensors provide direct electronic signal without the use of expensive signal transduction equipment and facilitates the immobilization of single stranded DNA (ssDNA) probe sequences on a wide variety of electrode substrates. It has been found that a range of nanomaterials such as metal nanoparticles (MNPs), carbon based nanomaterials, quantum dots (QDs), magnetic nanoparticles and polymeric NPs have been introduced in the sensor design to enhance the sensing performance of electrochemical DNA sensor. In this review, we discuss recent progress in the design and fabrication of efficient electrochemical genosensors based on carbon nanostructures such as carbon nanotubes, graphene, graphene oxide and nanodiamonds. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of robust building energy demand-side control strategy under uncertainty

NASA Astrophysics Data System (ADS)

Kim, Sean Hay

The potential of carbon emission regulations applied to an individual building will encourage building owners to purchase utility-provided green power or to employ onsite renewable energy generation. As both cases are based on intermittent renewable energy sources, demand side control is a fundamental precondition for maximizing the effectiveness of using renewable energy sources. Such control leads to a reduction in peak demand and/or in energy demand variability, therefore, such reduction in the demand profile eventually enhances the efficiency of an erratic supply of renewable energy. The combined operation of active thermal energy storage and passive building thermal mass has shown substantial improvement in demand-side control performance when compared to current state-of-the-art demand-side control measures. Specifically, "model-based" optimal control for this operation has the potential to significantly increase performance and bring economic advantages. However, due to the uncertainty in certain operating conditions in the field its control effectiveness could be diminished and/or seriously damaged, which results in poor performance. This dissertation pursues improvements of current demand-side controls under uncertainty by proposing a robust supervisory demand-side control strategy that is designed to be immune from uncertainty and perform consistently under uncertain conditions. Uniqueness and superiority of the proposed robust demand-side controls are found as below: a. It is developed based on fundamental studies about uncertainty and a systematic approach to uncertainty analysis. b. It reduces variability of performance under varied conditions, and thus avoids the worst case scenario. c. It is reactive in cases of critical "discrepancies" observed caused by the unpredictable uncertainty that typically scenario uncertainty imposes, and thus it increases control efficiency. This is obtainable by means of i) multi-source composition of weather forecasts including both historical archive and online sources and ii) adaptive Multiple model-based controls (MMC) to mitigate detrimental impacts of varying scenario uncertainties. The proposed robust demand-side control strategy verifies its outstanding demand-side control performance in varied and non-indigenous conditions compared to the existing control strategies including deterministic optimal controls. This result reemphasizes importance of the demand-side control for a building in the global carbon economy. It also demonstrates a capability of risk management of the proposed robust demand-side controls in highly uncertain situations, which eventually attains the maximum benefit in both theoretical and practical perspectives.

Preparation of the spacer for narrow electrode gap configuration in ionization-based gas sensor

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

Saheed, Mohamed Shuaib Mohamed; Mohamed, Norani Muti; Burhanudin, Zainal Arif

2012-09-26

Carbon nanotubes (CNTs) have started to be developed as the sensing element for ionization-based gas sensors due to the demand for improved sensitivity, selectivity, stability and other sensing properties beyond what can be offered by the conventional ones. Although these limitations have been overcome, the problems still remain with the conventional ionization-based gas sensors in that they are bulky and operating with large breakdown voltage and high temperature. Recent studies have shown that the breakdown voltage can be reduced by using nanostructured electrodes and narrow electrode gap. Nanostructured electrode in the form of aligned CNTs array with evenly distributed nanotipsmore » can enhance the linear electric field significantly. The later is attributed to the shorter conductivity path through narrow electrode gap. The paper presents the study on the design consideration in order to realize ionization based gas sensor using aligned carbon nanotubes array in an optimum sensor configuration with narrow electrode gap. Several deposition techniques were studied to deposit the spacer, the key component that can control the electrode gap. Plasma spray deposition, electron beam deposition and dry oxidation method were employed to obtain minimum film thickness around 32 {mu}m. For plasma spray method, sand blasting process is required in order to produce rough surface for strong bonding of the deposited film onto the surface. Film thickness, typically about 39 {mu}m can be obtained. For the electron beam deposition and dry oxidation, the film thickness is in the range of nanometers and thus unsuitable to produce the spacer. The deposited multilayer film consisting of copper, alumina and ferum on which CNTs array will be grown was found to be removed during the etching process. This is attributed to the high etching rate on the thin film which can be prevented by reducing the rate and having a thicker conductive copper film.« less

Cyber-physical geographical information service-enabled control of diverse in-situ sensors.

PubMed

Chen, Nengcheng; Xiao, Changjiang; Pu, Fangling; Wang, Xiaolei; Wang, Chao; Wang, Zhili; Gong, Jianya

2015-01-23

Realization of open online control of diverse in-situ sensors is a challenge. This paper proposes a Cyber-Physical Geographical Information Service-enabled method for control of diverse in-situ sensors, based on location-based instant sensing of sensors, which provides closed-loop feedbacks. The method adopts the concepts and technologies of newly developed cyber-physical systems (CPSs) to combine control with sensing, communication, and computation, takes advantage of geographical information service such as services provided by the Tianditu which is a basic geographic information service platform in China and Sensor Web services to establish geo-sensor applications, and builds well-designed human-machine interfaces (HMIs) to support online and open interactions between human beings and physical sensors through cyberspace. The method was tested with experiments carried out in two geographically distributed scientific experimental fields, Baoxie Sensor Web Experimental Field in Wuhan city and Yemaomian Landslide Monitoring Station in Three Gorges, with three typical sensors chosen as representatives using the prototype system Geospatial Sensor Web Common Service Platform. The results show that the proposed method is an open, online, closed-loop means of control.

Cyber-Physical Geographical Information Service-Enabled Control of Diverse In-Situ Sensors

PubMed Central

Chen, Nengcheng; Xiao, Changjiang; Pu, Fangling; Wang, Xiaolei; Wang, Chao; Wang, Zhili; Gong, Jianya

2015-01-01

Realization of open online control of diverse in-situ sensors is a challenge. This paper proposes a Cyber-Physical Geographical Information Service-enabled method for control of diverse in-situ sensors, based on location-based instant sensing of sensors, which provides closed-loop feedbacks. The method adopts the concepts and technologies of newly developed cyber-physical systems (CPSs) to combine control with sensing, communication, and computation, takes advantage of geographical information service such as services provided by the Tianditu which is a basic geographic information service platform in China and Sensor Web services to establish geo-sensor applications, and builds well-designed human-machine interfaces (HMIs) to support online and open interactions between human beings and physical sensors through cyberspace. The method was tested with experiments carried out in two geographically distributed scientific experimental fields, Baoxie Sensor Web Experimental Field in Wuhan city and Yemaomian Landslide Monitoring Station in Three Gorges, with three typical sensors chosen as representatives using the prototype system Geospatial Sensor Web Common Service Platform. The results show that the proposed method is an open, online, closed-loop means of control. PMID:25625906

Location Dependency and Antenna/Body/Sensor-Lead Interaction Effects in a Cell-Phone Based GSM 1800 Telemedicine Link

DTIC Science & Technology

2001-10-25

The error-free requirement of today’s cell - phone based telemedicine systems demands investigations into the potential causes of service degradation...to the handset’s antenna can have on system performance Changes in lead orientation in the near field of the radiating unit ( cell - phone & antenna

Defense Small Business Innovation Research Program (SBIR). Volume 4. Defense Agencies Abstracts of Phase 1 Awards 1987.

DTIC Science & Technology

1988-04-01

DEMANDS THE USE OF THICK HOLOGRAMS. THESE THICK HOLOGRAMS, HOWEVER, SUFFER FROM A NONUNIFORMITY THAT RESULTS FROM FEEDBACK INFLUENCE OF THE PARTLY EXPOSED...CRYOCOOLER FOR SPACE-BASED LONG WAVELENGTH INFRARED SE TOPIC# 3 OFFICE: LONG WAVELENGTH INFRARED ( LWIR ) SENSORS ARE BECOMING INCREASINGLY IMPORTANT...THAT CAN OPERATE UNATTENDED FO1 LONG PERIODS IN SPACE BETWqEEN 20K AND 4K, THUS OPENING THE POSSIBILITY OF OPERATIVE LWIR SENSORS IN THE 10 TO 140

A High Temperature Capacitive Pressure Sensor Based on Alumina Ceramic for in Situ Measurement at 600 °C

PubMed Central

Tan, Qiulin; Li, Chen; Xiong, Jijun; Jia, Pinggang; Zhang, Wendong; Liu, Jun; Xue, Chenyang; Hong, Yingping; Ren, Zhong; Luo, Tao

2014-01-01

In response to the growing demand for in situ measurement of pressure in high-temperature environments, a high temperature capacitive pressure sensor is presented in this paper. A high-temperature ceramic material-alumina is used for the fabrication of the sensor, and the prototype sensor consists of an inductance, a variable capacitance, and a sealed cavity integrated in the alumina ceramic substrate using a thick-film integrated technology. The experimental results show that the proposed sensor has stability at 850 °C for more than 20 min. The characterization in high-temperature and pressure environments successfully demonstrated sensing capabilities for pressure from 1 to 5 bar up to 600 °C, limited by the sensor test setup. At 600 °C, the sensor achieves a linear characteristic response, and the repeatability error, hysteresis error and zero-point drift of the sensor are 8.3%, 5.05% and 1%, respectively. PMID:24487624

Measurement of Rotating Blade Tip Clearance with Fibre-Optic Probe

NASA Astrophysics Data System (ADS)

Cao, S. Z.; Duan, F. J.; Zhang, Y. G.

2006-10-01

This paper described a tip clearance measuring system with fibre-optic probe. The system is based on a novel tip clearance sensor of optical fibre-bundle mounted on the casing, rotating speed synchronization sensor mounted on the rotating shaft, the tip clearance preamplification processing circuit followed by high speed data-acquisition unit. A novel tip clearance sensor of trifurcated optical fibre bundle was proposed and demonstrated. It is independent of material of measured surface but capacitive probe demands target conductive. Measurements can be taken under severe conditions such as ionization. Sensor circuitry and data acquisition circuit were successfully designed. With the help of Rotation synchronized sensor, all the blades can be detected in real-time. Because of fibre-optic sensor, the measuring system has commendably frequency response, which can work well in high rotating speed from 0-15000rpm.The measurement range of tip clearance is 0-3mm with 25um precision.

An On-Demand Emergency Packet Transmission Scheme for Wireless Body Area Networks.

PubMed

Al Ameen, Moshaddique; Hong, Choong Seon

2015-12-04

The rapid developments of sensor devices that can actively monitor human activities have given rise to a new field called wireless body area network (BAN). A BAN can manage devices in, on and around the human body. Major requirements of such a network are energy efficiency, long lifetime, low delay, security, etc. Traffic in a BAN can be scheduled (normal) or event-driven (emergency). Traditional media access control (MAC) protocols use duty cycling to improve performance. A sleep-wake up cycle is employed to save energy. However, this mechanism lacks features to handle emergency traffic in a prompt and immediate manner. To deliver an emergency packet, a node has to wait until the receiver is awake. It also suffers from overheads, such as idle listening, overhearing and control packet handshakes. An external radio-triggered wake up mechanism is proposed to handle prompt communication. It can reduce the overheads and improve the performance through an on-demand scheme. In this work, we present a simple-to-implement on-demand packet transmission scheme by taking into considerations the requirements of a BAN. The major concern is handling the event-based emergency traffic. The performance analysis of the proposed scheme is presented. The results showed significant improvements in the overall performance of a BAN compared to state-of-the-art protocols in terms of energy consumption, delay and lifetime.

An On-Demand Emergency Packet Transmission Scheme for Wireless Body Area Networks

PubMed Central

Al Ameen, Moshaddique; Hong, Choong Seon

2015-01-01

The rapid developments of sensor devices that can actively monitor human activities have given rise to a new field called wireless body area network (BAN). A BAN can manage devices in, on and around the human body. Major requirements of such a network are energy efficiency, long lifetime, low delay, security, etc. Traffic in a BAN can be scheduled (normal) or event-driven (emergency). Traditional media access control (MAC) protocols use duty cycling to improve performance. A sleep-wake up cycle is employed to save energy. However, this mechanism lacks features to handle emergency traffic in a prompt and immediate manner. To deliver an emergency packet, a node has to wait until the receiver is awake. It also suffers from overheads, such as idle listening, overhearing and control packet handshakes. An external radio-triggered wake up mechanism is proposed to handle prompt communication. It can reduce the overheads and improve the performance through an on-demand scheme. In this work, we present a simple-to-implement on-demand packet transmission scheme by taking into considerations the requirements of a BAN. The major concern is handling the event-based emergency traffic. The performance analysis of the proposed scheme is presented. The results showed significant improvements in the overall performance of a BAN compared to state-of-the-art protocols in terms of energy consumption, delay and lifetime. PMID:26690161

Immobilization of pH-sensitive CdTe Quantum Dots in a Poly(acrylate) Hydrogel for Microfluidic Applications

NASA Astrophysics Data System (ADS)

Franke, M.; Leubner, S.; Dubavik, A.; George, A.; Savchenko, T.; Pini, C.; Frank, P.; Melnikau, D.; Rakovich, Y.; Gaponik, N.; Eychmüller, A.; Richter, A.

2017-04-01

Microfluidic devices present the basis of modern life sciences and chemical information processing. To control the flow and to allow optical readout, a reliable sensor material that can be easily utilized for microfluidic systems is in demand. Here, we present a new optical readout system for pH sensing based on pH sensitive, photoluminescent glutathione capped cadmium telluride quantum dots that are covalently immobilized in a poly(acrylate) hydrogel. For an applicable pH sensing the generated hybrid material is integrated in a microfluidic sensor chip setup. The hybrid material not only allows in situ readout, but also possesses valve properties due to the swelling behavior of the poly(acrylate) hydrogel. In this work, the swelling property of the hybrid material is utilized in a microfluidic valve seat, where a valve opening process is demonstrated by a fluid flow change and in situ monitored by photoluminescence quenching. This discrete photoluminescence detection (ON/OFF) of the fluid flow change (OFF/ON) enables upcoming chemical information processing.

Overview of advances in water management in agricultural production:Sensor based irrigation management

USDA-ARS?s Scientific Manuscript database

Technological advances in irrigated agriculture are crucial to meeting the challenge of increasing demand for agricultural products given limited quality and quantity of water resources for irrigation, impacts of climate variability, and the need to reduce environmental impacts. Multidisciplinary ap...

Note: Reliable and non-contact 6D motion tracking system based on 2D laser scanners for cargo transportation

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

Kim, Young-Keun, E-mail: ykkim@handong.edu; Kim, Kyung-Soo

Maritime transportation demands an accurate measurement system to track the motion of oscillating container boxes in real time. However, it is a challenge to design a sensor system that can provide both reliable and non-contact methods of 6-DOF motion measurements of a remote object for outdoor applications. In the paper, a sensor system based on two 2D laser scanners is proposed for detecting the relative 6-DOF motion of a crane load in real time. Even without implementing a camera, the proposed system can detect the motion of a remote object using four laser beam points. Because it is a laser-basedmore » sensor, the system is expected to be highly robust to sea weather conditions.« less

Automatic systems and the low-level wind hazard

NASA Technical Reports Server (NTRS)

Schaeffer, Dwight R.

1987-01-01

Automatic flight control systems provide means for significantly enhancing survivability in severe wind hazards. The technology required to produce the necessary control algorithms is available and has been made technically feasible by the advent of digital flight control systems and accurate, low-noise sensors, especially strap-down inertial sensors. The application of this technology and these means has not generally been enabled except for automatic landing systems, and even then the potential has not been fully exploited. To fully exploit the potential of automatic systems for enhancing safety in wind hazards requires providing incentives, creating demand, inspiring competition, education, and eliminating prejudicial disincentitives to overcome the economic penalties associated with the extensive and riskly development and certification of these systems. If these changes will come about at all, it will likely be through changes in the regulations provided by the certifying agencies.

Bluetooth-based wireless sensor networks

NASA Astrophysics Data System (ADS)

You, Ke; Liu, Rui Qiang

2007-11-01

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

Intrinsic and metal-doped gallium oxide based high-temperature oxygen sensors for combustion processes

NASA Astrophysics Data System (ADS)

Rubio, Ernesto Javier

Currently, there is enormous interest in research, development and optimization of the combustion processes for energy harvesting. Recent statistical and economic analyses estimated that by improving the coal-based firing/combustion processes in the power plants, savings up to $450-500 million yearly can be achieved. Advanced sensors and controls capable of withstanding extreme environments such as high temperatures, highly corrosive atmospheres, and high pressures are critical to such efficiency enhancement and cost savings. For instance, optimization of the combustion processes in power generation systems can be achieved by sensing, monitoring and control of oxygen, which is a measure of the completeness of the process and can lead to enhanced efficiency and reduced greenhouse gas emissions. However, despite the fact that there exists a very high demand for advanced sensors, the existing technologies suffer from poor 'response and recovery times' and 'long-term stability.' Motivated by the aforementioned technological challenges, the present work was focused on high-temperature (≥700 °C) oxygen sensors for application in power generation systems. The objective of the present work is to investigate nanostructured gallium oxide (2O3) based sensors for oxygen sensing, where we propose to conduct in-depth exploration of the role of refractory metal (tungsten, W, in this case) doping into 2O 3 to enhance the sensitivity, selectivity, stability ("3S" criteria) and reliability of such sensors while keeping cost economical. Tungsten (W) doped gallium oxide (2O3) thin films were deposited via rf-magnetron co-sputtering of W-metal and Ga2O3-ceramic targets. Films were produced by varying the sputtering power applied to the W-target in order to achieve variable W content into 2O3 films while substrate temperature was kept constant at 500 °C. Chemical composition, chemical valence states, microstructure and crystal structure of as-grown and post-annealed W-doped 2O3 films were evaluated as a function of W-content. The structural analyses indicate the formation of monoclinic beta-phase 2O3 in as-grown W-doped 2O3 films for all W-content. Thermally induced secondary phase (W-oxide) formation was observed after the annealing process. Chemical analysis demonstrates the increasing W atomic percentage in the films with increasing sputtering power, whereas the main metallic ionic species for the films are W6+ and Ga3+. Evidence of W interdiffusion due to the annealing process is presented, and the mechanism of diffusion is discussed. Surface morphology of the films is also discussed, and the transition to mesoporous surface is observed after annealing. Finally, the oxygen sensor performance evaluation demonstrated that the W-incorporated 2O3 exhibits improved response time compared to intrinsic 2O3 based oxygen sensors.

An Efficient Biometric-Based Algorithm Using Heart Rate Variability for Securing Body Sensor Networks

PubMed Central

Pirbhulal, Sandeep; Zhang, Heye; Mukhopadhyay, Subhas Chandra; Li, Chunyue; Wang, Yumei; Li, Guanglin; Wu, Wanqing; Zhang, Yuan-Ting

2015-01-01

Body Sensor Network (BSN) is a network of several associated sensor nodes on, inside or around the human body to monitor vital signals, such as, Electroencephalogram (EEG), Photoplethysmography (PPG), Electrocardiogram (ECG), etc. Each sensor node in BSN delivers major information; therefore, it is very significant to provide data confidentiality and security. All existing approaches to secure BSN are based on complex cryptographic key generation procedures, which not only demands high resource utilization and computation time, but also consumes large amount of energy, power and memory during data transmission. However, it is indispensable to put forward energy efficient and computationally less complex authentication technique for BSN. In this paper, a novel biometric-based algorithm is proposed, which utilizes Heart Rate Variability (HRV) for simple key generation process to secure BSN. Our proposed algorithm is compared with three data authentication techniques, namely Physiological Signal based Key Agreement (PSKA), Data Encryption Standard (DES) and Rivest Shamir Adleman (RSA). Simulation is performed in Matlab and results suggest that proposed algorithm is quite efficient in terms of transmission time utilization, average remaining energy and total power consumption. PMID:26131666

An Efficient Biometric-Based Algorithm Using Heart Rate Variability for Securing Body Sensor Networks.

PubMed

Pirbhulal, Sandeep; Zhang, Heye; Mukhopadhyay, Subhas Chandra; Li, Chunyue; Wang, Yumei; Li, Guanglin; Wu, Wanqing; Zhang, Yuan-Ting

2015-06-26

Body Sensor Network (BSN) is a network of several associated sensor nodes on, inside or around the human body to monitor vital signals, such as, Electroencephalogram (EEG), Photoplethysmography (PPG), Electrocardiogram (ECG), etc. Each sensor node in BSN delivers major information; therefore, it is very significant to provide data confidentiality and security. All existing approaches to secure BSN are based on complex cryptographic key generation procedures, which not only demands high resource utilization and computation time, but also consumes large amount of energy, power and memory during data transmission. However, it is indispensable to put forward energy efficient and computationally less complex authentication technique for BSN. In this paper, a novel biometric-based algorithm is proposed, which utilizes Heart Rate Variability (HRV) for simple key generation process to secure BSN. Our proposed algorithm is compared with three data authentication techniques, namely Physiological Signal based Key Agreement (PSKA), Data Encryption Standard (DES) and Rivest Shamir Adleman (RSA). Simulation is performed in Matlab and results suggest that proposed algorithm is quite efficient in terms of transmission time utilization, average remaining energy and total power consumption.

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

Fachechi, Alessio; Mainetti, Luca; Palano, Laura

The continuously rising demand for electricity has prompted governments and industries to research more effective energy management systems. The Internet of Things paradigm is a valuable add-on for controlling and managing the energy appliances such as Plug-in Electrical Vehicles (PEV) charging stations. In this paper, we present a Demand Response implementation for PEV charging stations able to use Wireless Sensor Network technologies based on the Constrained Application Protocol (CoAP). We developed a self-service kiosk system by which the user can autonomously swipe his/her credit card and choose the charging station to enable. When a user plugs his/her vehicle to themore » station, s/he subscribes his availability to share a portion of its energy. When the grid requests a contribution from the PEVs, the kiosk sends a CoAP message to the available stations and the energy flow is inverted (Vehicle-to-Grid). At the end of the charging process, the user's credit card gets charged with a discounted bill.« less

Three-Dimensional Printed Poly(vinyl alcohol) Substrate with Controlled On-Demand Degradation for Transient Electronics.

PubMed

Yoon, Jinsu; Han, Jungmin; Choi, Bongsik; Lee, Yongwoo; Kim, Yeamin; Park, Jinhee; Lim, Meehyun; Kang, Min-Ho; Kim, Dae Hwan; Kim, Dong Myong; Kim, Sungho; Choi, Sung-Jin

2018-05-25

Electronics that degrade after stable operation for a desired operating time, called transient electronics, are of great interest in many fields, including biomedical implants, secure memory devices, and environmental sensors. Thus, the development of transient materials is critical for the advancement of transient electronics and their applications. However, previous reports have mostly relied on achieving transience in aqueous solutions, where the transience time is largely predetermined based on the materials initially selected at the beginning of the fabrication. Therefore, accurate control of the transience time is difficult, thereby limiting their application. In this work, we demonstrate transient electronics based on a water-soluble poly(vinyl alcohol) (PVA) substrate on which carbon nanotube (CNT)-based field-effect transistors were fabricated. We regulated the structural parameters of the PVA substrate using a three-dimensional (3D) printer to accurately control and program the transience time of the PVA substrate in water. The 3D printing technology can produce complex objects directly, thus enabling the efficient fabrication of a transient substrate with a prescribed and controlled transience time. In addition, the 3D printer was used to develop a facile method for the selective and partial destruction of electronics.

Parallel robot for micro assembly with integrated innovative optical 3D-sensor

NASA Astrophysics Data System (ADS)

Hesselbach, Juergen; Ispas, Diana; Pokar, Gero; Soetebier, Sven; Tutsch, Rainer

2002-10-01

Recent advances in the fields of MEMS and MOEMS often require precise assembly of very small parts with an accuracy of a few microns. In order to meet this demand, a new approach using a robot based on parallel mechanisms in combination with a novel 3D-vision system has been chosen. The planar parallel robot structure with 2 DOF provides a high resolution in the XY-plane. It carries two additional serial axes for linear and rotational movement in/about z direction. In order to achieve high precision as well as good dynamic capabilities, the drive concept for the parallel (main) axes incorporates air bearings in combination with a linear electric servo motors. High accuracy position feedback is provided by optical encoders with a resolution of 0.1 μm. To allow for visualization and visual control of assembly processes, a camera module fits into the hollow tool head. It consists of a miniature CCD camera and a light source. In addition a modular gripper support is integrated into the tool head. To increase the accuracy a control loop based on an optoelectronic sensor will be implemented. As a result of an in-depth analysis of different approaches a photogrammetric system using one single camera and special beam-splitting optics was chosen. A pattern of elliptical marks is applied to the surfaces of workpiece and gripper. Using a model-based recognition algorithm the image processing software identifies the gripper and the workpiece and determines their relative position. A deviation vector is calculated and fed into the robot control to guide the gripper.

Event-based Sensing for Space Situational Awareness

NASA Astrophysics Data System (ADS)

Cohen, G.; Afshar, S.; van Schaik, A.; Wabnitz, A.; Bessell, T.; Rutten, M.; Morreale, B.

A revolutionary type of imaging device, known as a silicon retina or event-based sensor, has recently been developed and is gaining in popularity in the field of artificial vision systems. These devices are inspired by a biological retina and operate in a significantly different way to traditional CCD-based imaging sensors. While a CCD produces frames of pixel intensities, an event-based sensor produces a continuous stream of events, each of which is generated when a pixel detects a change in log light intensity. These pixels operate asynchronously and independently, producing an event-based output with high temporal resolution. There are also no fixed exposure times, allowing these devices to offer a very high dynamic range independently for each pixel. Additionally, these devices offer high-speed, low power operation and a sparse spatiotemporal output. As a consequence, the data from these sensors must be interpreted in a significantly different way to traditional imaging sensors and this paper explores the advantages this technology provides for space imaging. The applicability and capabilities of event-based sensors for SSA applications are demonstrated through telescope field trials. Trial results have confirmed that the devices are capable of observing resident space objects from LEO through to GEO orbital regimes. Significantly, observations of RSOs were made during both day-time and nighttime (terminator) conditions without modification to the camera or optics. The event based sensor’s ability to image stars and satellites during day-time hours offers a dramatic capability increase for terrestrial optical sensors. This paper shows the field testing and validation of two different architectures of event-based imaging sensors. An eventbased sensor’s asynchronous output has an intrinsically low data-rate. In addition to low-bandwidth communications requirements, the low weight, low-power and high-speed make them ideally suitable to meeting the demanding challenges required by space-based SSA systems. Results from these experiments and the systems developed highlight the applicability of event-based sensors to ground and space-based SSA tasks.

The solution of target assignment problem in command and control decision-making behaviour simulation

NASA Astrophysics Data System (ADS)

Li, Ni; Huai, Wenqing; Wang, Shaodan

2017-08-01

C2 (command and control) has been understood to be a critical military component to meet an increasing demand for rapid information gathering and real-time decision-making in a dynamically changing battlefield environment. In this article, to improve a C2 behaviour model's reusability and interoperability, a behaviour modelling framework was proposed to specify a C2 model's internal modules and a set of interoperability interfaces based on the C-BML (coalition battle management language). WTA (weapon target assignment) is a typical C2 autonomous decision-making behaviour modelling problem. Different from most WTA problem descriptions, here sensors were considered to be available resources of detection and the relationship constraints between weapons and sensors were also taken into account, which brought it much closer to actual application. A modified differential evolution (MDE) algorithm was developed to solve this high-dimension optimisation problem and obtained an optimal assignment plan with high efficiency. In case study, we built a simulation system to validate the proposed C2 modelling framework and interoperability interface specification. Also, a new optimisation solution was used to solve the WTA problem efficiently and successfully.

Thirty Meter Telescope narrow-field infrared adaptive optics system real-time controller prototyping results

NASA Astrophysics Data System (ADS)

Smith, Malcolm; Kerley, Dan; Chapin, Edward L.; Dunn, Jennifer; Herriot, Glen; Véran, Jean-Pierre; Boyer, Corinne; Ellerbroek, Brent; Gilles, Luc; Wang, Lianqi

2016-07-01

Prototyping and benchmarking was performed for the Real-Time Controller (RTC) of the Narrow Field InfraRed Adaptive Optics System (NFIRAOS). To perform wavefront correction, NFIRAOS utilizes two deformable mirrors (DM) and one tip/tilt stage (TTS). The RTC receives wavefront information from six Laser Guide Star (LGS) Shack- Hartmann WaveFront Sensors (WFS), one high-order Natural Guide Star Pyramid WaveFront Sensor (PWFS) and multiple low-order instrument detectors. The RTC uses this information to determine the commands to send to the wavefront correctors. NFIRAOS is the first light AO system for the Thirty Meter Telescope (TMT). The prototyping was performed using dual-socket high performance Linux servers with the real-time (PREEMPT_RT) patch and demonstrated the viability of a commercial off-the-shelf (COTS) hardware approach to large scale AO reconstruction. In particular, a large custom matrix vector multiplication (MVM) was benchmarked which met the required latency requirements. In addition all major inter-machine communication was verified to be adequate using 10Gb and 40Gb Ethernet. The results of this prototyping has enabled a CPU-based NFIRAOS RTC design to proceed with confidence and that COTS hardware can be used to meet the demanding performance requirements.

Geometric Positioning for Satellite Imagery without Ground Control Points by Exploiting Repeated Observation.

PubMed

Ma, Zhenling; Wu, Xiaoliang; Yan, Li; Xu, Zhenliang

2017-01-26

With the development of space technology and the performance of remote sensors, high-resolution satellites are continuously launched by countries around the world. Due to high efficiency, large coverage and not being limited by the spatial regulation, satellite imagery becomes one of the important means to acquire geospatial information. This paper explores geometric processing using satellite imagery without ground control points (GCPs). The outcome of spatial triangulation is introduced for geo-positioning as repeated observation. Results from combining block adjustment with non-oriented new images indicate the feasibility of geometric positioning with the repeated observation. GCPs are a must when high accuracy is demanded in conventional block adjustment; the accuracy of direct georeferencing with repeated observation without GCPs is superior to conventional forward intersection and even approximate to conventional block adjustment with GCPs. The conclusion is drawn that taking the existing oriented imagery as repeated observation enhances the effective utilization of previous spatial triangulation achievement, which makes the breakthrough for repeated observation to improve accuracy by increasing the base-height ratio and redundant observation. Georeferencing tests using data from multiple sensors and platforms with the repeated observation will be carried out in the follow-up research.

Survey of Visual and Force/Tactile Control of Robots for Physical Interaction in Spain

PubMed Central

Garcia, Gabriel J.; Corrales, Juan A.; Pomares, Jorge; Torres, Fernando

2009-01-01

Sensors provide robotic systems with the information required to perceive the changes that happen in unstructured environments and modify their actions accordingly. The robotic controllers which process and analyze this sensory information are usually based on three types of sensors (visual, force/torque and tactile) which identify the most widespread robotic control strategies: visual servoing control, force control and tactile control. This paper presents a detailed review on the sensor architectures, algorithmic techniques and applications which have been developed by Spanish researchers in order to implement these mono-sensor and multi-sensor controllers which combine several sensors. PMID:22303146

Multi-phenomenology Observation Network Evaluation Tool'' (MONET)

NASA Astrophysics Data System (ADS)

Oltrogge, D.; North, P.; Vallado, D.

2014-09-01

Evaluating overall performance of an SSA "system-of-systems" observational network collecting against thousands of Resident Space Objects (RSO) is very difficult for typical tasking or scheduling-based analysis tools. This is further complicated by networks that have a wide variety of sensor types and phenomena, to include optical, radar and passive RF types, each having unique resource, ops tempo, competing customer and detectability constraints. We present details of the Multi-phenomenology Observation Network Evaluation Tool (MONET), which circumvents these difficulties by assessing the ideal performance of such a network via a digitized supply-vs-demand approach. Cells of each sensors supply time are distributed among RSO targets of interest to determine the average performance of the network against that set of RSO targets. Orbit Determination heuristics are invoked to represent observation quantity and geometry notionally required to obtain the desired orbit estimation quality. To feed this approach, we derive the detectability and collection rate performance of optical, radar and passive RF sensor physical and performance characteristics. We then prioritize the selected RSO targets according to object size, active/inactive status, orbit regime, and/or other considerations. Finally, the OD-derived tracking demands of each RSO of interest are levied against remaining sensor supply until either (a) all sensor time is exhausted; or (b) the list of RSO targets is exhausted. The outputs from MONET include overall network performance metrics delineated by sensor type, objects and orbits tracked, along with likely orbit accuracies which might result from the conglomerate network tracking.

Leveraging Aging in Place Through Sensor-Enhanced In-Home Monitoring.

PubMed

Wang, Ju; Wang, Jing; Miao, Hongyu; Marschollek, Michael; Wolf, Klaus-Hendrik; Lynch, Kerry A; Gong, Yang

2018-01-01

Seniors expect to age in place, which means living in their own homes as long as possible with familiar facilities and environments. Due to the capability of continuous and unobtrusive monitoring, the sensor-enhanced in-ho monitoring is regarded as a promising solution to support aging in place. In this paper, by reviewing three influential projects in this field of in-home monitoring for aging in place, we present our opinions and suggestions on the development of informatics-supported aging in place for its practical application in healthcare such as diagnosis and nursing in the era of data science. To promote the practical usage of in-home monitoring in aging, we highlight the gap between demands and available approaches. We conclude that in the next stage we should design demand-oriented system, conduct evidence-based research and accelerate interdisciplinary collaboration.

A MEMS approach to determine the biochemical oxygen demand (BOD) of wastewaters

NASA Astrophysics Data System (ADS)

Recoules, L.; Migaou, A.; Dollat, X.; Thouand, G.; Gue, A. M.; Boukabache, A.

2017-07-01

A MEMS approach to obtain an efficient tool for the evaluation of the biochemical oxygen demand (BOD) of wastewaters is introduced. Its operating principle is based on the measurement of oxygen concentration in water samples containing organic pollutants and specific bacteria. The microsystem has been designed to perform multiple and parallel measurements in a poly-wells microfluidic device. The monitoring of the bacterial activity is ensured by optical sensors incorporated in each well of the fluidic network. By using an optode sensor, it is hereby demonstrated that this approach is efficient to measure organic pollutants by testing different Luria Bertani buffer dilutions. These results also show that it is possible to reduce the duration of measurements from 5 d (BOD5) of the standard approach to few hours, typically 3 h-5 h.

Design and Test of a Soil Profile Moisture Sensor Based on Sensitive Soil Layers

PubMed Central

Liu, Cheng; Qian, Hongzhou; Cao, Weixing; Ni, Jun

2018-01-01

To meet the demand of intelligent irrigation for accurate moisture sensing in the soil vertical profile, a soil profile moisture sensor was designed based on the principle of high-frequency capacitance. The sensor consists of five groups of sensing probes, a data processor, and some accessory components. Low-resistivity copper rings were used as components of the sensing probes. Composable simulation of the sensor’s sensing probes was carried out using a high-frequency structure simulator. According to the effective radiation range of electric field intensity, width and spacing of copper ring were set to 30 mm and 40 mm, respectively. A parallel resonance circuit of voltage-controlled oscillator and high-frequency inductance-capacitance (LC) was designed for signal frequency division and conditioning. A data processor was used to process moisture-related frequency signals for soil profile moisture sensing. The sensor was able to detect real-time soil moisture at the depths of 20, 30, and 50 cm and conduct online inversion of moisture in the soil layer between 0–100 cm. According to the calibration results, the degree of fitting (R2) between the sensor’s measuring frequency and the volumetric moisture content of soil sample was 0.99 and the relative error of the sensor consistency test was 0–1.17%. Field tests in different loam soils showed that measured soil moisture from our sensor reproduced the observed soil moisture dynamic well, with an R2 of 0.96 and a root mean square error of 0.04. In a sensor accuracy test, the R2 between the measured value of the proposed sensor and that of the Diviner2000 portable soil moisture monitoring system was higher than 0.85, with a relative error smaller than 5%. The R2 between measured values and inversed soil moisture values for other soil layers were consistently higher than 0.8. According to calibration test and field test, this sensor, which features low cost, good operability, and high integration, is qualified for precise agricultural irrigation with stable performance and high accuracy. PMID:29883420

Distributed Autonomous Control Action Based on Sensor and Mission Fusion

DTIC Science & Technology

2005-09-01

programmable control algorithm driven by the readings of two pressure switch sensors located on either side of the valve unit. Thus, a micro-controller...and Characterization The process of leak detection and characterization must be accomplished with a set of pressure switch sensors. This sensor...economically supplementing existing widely used pressure switch type sensors which are characterized by prohibitively long inertial lag responses

Design and fabrication of non silicon substrate based MEMS energy harvester for arbitrary surface applications

NASA Astrophysics Data System (ADS)

Balpande, Suresh S.; Pande, Rajesh S.

2016-04-01

Internet of Things (IoT) uses MEMS sensor nodes and actuators to sense and control objects through Internet. IOT deploys millions of chemical battery driven sensors at different locations which are not reliable many times because of frequent requirement of charging & battery replacement in case of underground laying, placement at harsh environmental conditions, huge count and difference between demand (24 % per year) and availability (energy density growing rate 8% per year). Energy harvester fabricated on silicon wafers have been widely used in manufacturing MEMS structures. These devices require complex fabrication processes, costly chemicals & clean room. In addition to this silicon wafer based devices are not suitable for curved surfaces like pipes, human bodies, organisms, or other arbitrary surface like clothes, structure surfaces which does not have flat and smooth surface always. Therefore, devices based on rigid silicon wafers are not suitable for these applications. Flexible structures are the key solution for this problems. Energy transduction mechanism generates power from free surrounding vibrations or impact. Sensor nodes application has been purposefully selected due to discrete power requirement at low duty cycle. Such nodes require an average power budget in the range of about 0.1 microwatt to 1 mW over a period of 3-5 seconds. Energy harvester is the best alternate source in contrast with battery for sensor node application. Novel design of Energy Harvester based on cheapest flexible non silicon substrate i.e. cellulose acetate substrate have been modeled, simulated and analyzed on COMSOL multiphysics and fabricated using sol-gel spin coating setup. Single cantilever based harvester generates 60-75 mV peak electric potential at 22Hz frequency and approximately 22 µW power at 1K-Ohm load. Cantilever array can be employed for generating higher voltage by replicating this structure. This work covers design, optimization, fabrication of harvester and schottky diodes based voltage multiplier.

Design and fabrication of non silicon substrate based MEMS energy harvester for arbitrary surface applications

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

Balpande, Suresh S., E-mail: balpandes@rknec.edu; Pande, Rajesh S.

Internet of Things (IoT) uses MEMS sensor nodes and actuators to sense and control objects through Internet. IOT deploys millions of chemical battery driven sensors at different locations which are not reliable many times because of frequent requirement of charging & battery replacement in case of underground laying, placement at harsh environmental conditions, huge count and difference between demand (24 % per year) and availability (energy density growing rate 8% per year). Energy harvester fabricated on silicon wafers have been widely used in manufacturing MEMS structures. These devices require complex fabrication processes, costly chemicals & clean room. In addition tomore » this silicon wafer based devices are not suitable for curved surfaces like pipes, human bodies, organisms, or other arbitrary surface like clothes, structure surfaces which does not have flat and smooth surface always. Therefore, devices based on rigid silicon wafers are not suitable for these applications. Flexible structures are the key solution for this problems. Energy transduction mechanism generates power from free surrounding vibrations or impact. Sensor nodes application has been purposefully selected due to discrete power requirement at low duty cycle. Such nodes require an average power budget in the range of about 0.1 microwatt to 1 mW over a period of 3-5 seconds. Energy harvester is the best alternate source in contrast with battery for sensor node application. Novel design of Energy Harvester based on cheapest flexible non silicon substrate i.e. cellulose acetate substrate have been modeled, simulated and analyzed on COMSOL multiphysics and fabricated using sol-gel spin coating setup. Single cantilever based harvester generates 60-75 mV peak electric potential at 22Hz frequency and approximately 22 µW power at 1K-Ohm load. Cantilever array can be employed for generating higher voltage by replicating this structure. This work covers design, optimization, fabrication of harvester and schottky diodes based voltage multiplier.« less

Food pathogen detection using Ag nanorod-based surface plasmon resonance sensor

USDA-ARS?s Scientific Manuscript database

Food safety is world-wide issue for protecting public health. Many researchers have been working on development of biosensors for pathogenic bacteria detection. However, current biosensing methods and techniques do not meet the requirement of demanding as a biosensor in terms of sensitivity, speci...

QPA-CLIPS: A language and representation for process control

NASA Technical Reports Server (NTRS)

Freund, Thomas G.

1994-01-01

QPA-CLIPS is an extension of CLIPS oriented towards process control applications. Its constructs define a dependency network of process actions driven by sensor information. The language consists of three basic constructs: TASK, SENSOR, and FILTER. TASK's define the dependency network describing alternative state transitions for a process. SENSOR's and FILTER's define sensor information sources used to activate state transitions within the network. Deftemplate's define these constructs and their run-time environment is an interpreter knowledge base, performing pattern matching on sensor information and so activating TASK's in the dependency network. The pattern matching technique is based on the repeatable occurrence of a sensor data pattern. QPA-CIPS has been successfully tested on a SPARCStation providing supervisory control to an Allen-Bradley PLC 5 controller driving molding equipment.

New generation of the health monitoring system SMS 2001

NASA Astrophysics Data System (ADS)

Berndt, Rolf-Dietrich; Schwesinger, Peter

2001-08-01

The Structure Monitoring System SMS 2001 (applied for patent) represents a modular structured multi-component measurement devise for use under outdoor conditions. Besides usual continuously (static) measurements of e.g. environmental parameters and structure related responses the SMS is able to register also short term dynamic events automatically with measurement frequencies up to 1 kHz. A larger range of electrical sensors is able to be used. On demand a solar based power supply can be realized. The SMS 2001 is adaptable in a wide range, it is space-saving in its geometric structure and can meet very various demands of the users. The system is applicable preferably for small and medium sized concrete and steel structures (besides buildings and bridges also for special cases). It is suitable to support the efficient concept of a controlled life time extension especially in the case of pre-damaged structures. The interactive communication between SMS and the central office is completely remote controlled. Two point or multi-point connections using the internet can be realized. The measurement data are stored in a central data bank. A safe access supported by software modules can be organized in different levels, e.g. for scientific evaluation, service reasons or needs of authorities.

Choosing Sensor Configuration for a Flexible Structure Using Full Control Synthesis

NASA Technical Reports Server (NTRS)

Lind, Rick; Nalbantoglu, Volkan; Balas, Gary

1997-01-01

Optimal locations and types for feedback sensors which meet design constraints and control requirements are difficult to determine. This paper introduces an approach to choosing a sensor configuration based on Full Control synthesis. A globally optimal Full Control compensator is computed for each member of a set of sensor configurations which are feasible for the plant. The sensor configuration associated with the Full Control system achieving the best closed-loop performance is chosen for feedback measurements to an output feedback controller. A flexible structure is used as an example to demonstrate this procedure. Experimental results show sensor configurations chosen to optimize the Full Control performance are effective for output feedback controllers.

SiC Sensors in Extreme Environments: Real-time Hydrogen Monitoring for Energy Plant Applications

NASA Astrophysics Data System (ADS)

Ghosh, Ruby

2008-03-01

Clean, efficient energy production, such as the gasification of coal (syngas), requires physical and chemical sensors for exhaust gas monitoring as well as real-time control of the combustion process. Wide-bandgap semiconducting materials systems can meet the sensing demands in these extreme environments consisting of chemically corrosive gases at high temperature and pressure. We have developed a SiC based micro-sensor for detection of hydrogen containing species with millisecond response at 600 C. The sensor is a Pt-SiO2-SiC device with a dense Pt catalytic sensing film, capable of withstanding months of continuous high temperature operation. The device was characterized in robust sensing module that is compatible with an industrial reactor. We report on the performance of the SiC sensor in a simulated syngas ambient at 370 C containing the common interferants CO2, CH4 and CO [1]. In addition we demonstrate that hours of exposure to >=1000 ppm H2S and 15% water vapor does not degrade the sensor performance. To elucidate the mechanisms responsible for the hydrogen response of the sensor we have modeled the hydrogen adsorptions kinetics at the internal Pt-SiO2 interface, using both the Tempkin and Langmuir isotherms. Under the conditions appropriate for energy plant applications, the response of our sensor is significantly larger than that obtained from ultra-high vacuum electrochemical sensor measurements at high temperatures. We will discuss the role of morphology, at the nano to micro scale, on the enhanced catalytic activity observed for our Pt sensing films in response to a heated hydrogen gas stream at atmospheric pressure. [1] R. Loloee, B. Chorpening, S. Beers & R. Ghosh, Hydrogen monitoring for power plant applications using SiC sensors, Sens. Actuators B:Chem. (2007), doi:10.1016/j.snb.2007.07.118

Novel compact panomorph lens based vision system for monitoring around a vehicle

NASA Astrophysics Data System (ADS)

Thibault, Simon

2008-04-01

Automotive applications are one of the largest vision-sensor market segments and one of the fastest growing ones. The trend to use increasingly more sensors in cars is driven both by legislation and consumer demands for higher safety and better driving experiences. Awareness of what directly surrounds a vehicle affects safe driving and manoeuvring of a vehicle. Consequently, panoramic 360° Field of View imaging can contributes most to the perception of the world around the driver than any other sensors. However, to obtain a complete vision around the car, several sensor systems are necessary. To solve this issue, a customized imaging system based on a panomorph lens will provide the maximum information for the drivers with a reduced number of sensors. A panomorph lens is a hemispheric wide angle anamorphic lens with enhanced resolution in predefined zone of interest. Because panomorph lenses are optimized to a custom angle-to-pixel relationship, vision systems provide ideal image coverage that reduces and optimizes the processing. We present various scenarios which may benefit from the use of a custom panoramic sensor. We also discuss the technical requirements of such vision system. Finally we demonstrate how the panomorph based visual sensor is probably one of the most promising ways to fuse many sensors in one. For example, a single panoramic sensor on the front of a vehicle could provide all necessary information for assistance in crash avoidance, lane tracking, early warning, park aids, road sign detection, and various video monitoring views.

Absorbance Based Light Emitting Diode Optical Sensors and Sensing Devices

PubMed Central

O'Toole, Martina; Diamond, Dermot

2008-01-01

The ever increasing demand for in situ monitoring of health, environment and security has created a need for reliable, miniaturised sensing devices. To achieve this, appropriate analytical devices are required that possess operating characteristics of reliability, low power consumption, low cost, autonomous operation capability and compatibility with wireless communications systems. The use of light emitting diodes (LEDs) as light sources is one strategy, which has been successfully applied in chemical sensing. This paper summarises the development and advancement of LED based chemical sensors and sensing devices in terms of their configuration and application, with the focus on transmittance and reflectance absorptiometric measurements. PMID:27879829

Absorbance Based Light Emitting Diode Optical Sensors and Sensing Devices.

PubMed

O'Toole, Martina; Diamond, Dermot

2008-04-07

The ever increasing demand for in situ monitoring of health, environment and security has created a need for reliable, miniaturised sensing devices. To achieve this, appropriate analytical devices are required that possess operating characteristics of reliability, low power consumption, low cost, autonomous operation capability and compatibility with wireless communications systems. The use of light emitting diodes (LEDs) as light sources is one strategy, which has been successfully applied in chemical sensing. This paper summarises the development and advancement of LED based chemical sensors and sensing devices in terms of their configuration and application, with the focus on transmittance and reflectance absorptiometric measurements.

Moving forward in plant food safety and security through NanoBioSensors: Adopt or adapt biomedical technologies?

PubMed

Sharma, Tarun K; Ramanathan, Rajesh; Rakwal, Randeep; Agrawal, Ganesh K; Bansal, Vipul

2015-05-01

Plant-based foods are integral part of our day-to-day diet. Increasing world population has put forth an ever increasing demand for plant-based foods, and food security remains a major concern. Similarly, biological, chemical, and physical threats to our food and increasing regulatory demands to control the presence of foreign species in food products have made food safety a growing issue. Nanotechnology has already established its roots in diverse disciplines. However, the food industry is yet to harness the full potential of the unique capabilities offered by this next-generation technology. While there might be safety concerns in regards to integration of nanoproducts with our food products, an aspect of nanotechnology that can make remarkable contribution to different elements of the food chain is the use of nanobiosensors and diagnostic platforms for monitoring food traceability, quality, safety, and nutritional value. This brings us to an important question that whether existing diagnostic platforms that have already been well developed for biomedical and clinical application are suitable for food industry or whether the demands of the food industry are altogether different that may not allow adoption/adaptation of the existing technology. This review is an effort to raise this important "uncomfortable" yet "timely" question. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Ubiquitous Sensor Network Platform for Integrating Smart Devices into the Semantic Sensor Web

PubMed Central

de Vera, David Díaz Pardo; Izquierdo, Álvaro Sigüenza; Vercher, Jesús Bernat; Gómez, Luis Alfonso Hernández

2014-01-01

Ongoing Sensor Web developments make a growing amount of heterogeneous sensor data available to smart devices. This is generating an increasing demand for homogeneous mechanisms to access, publish and share real-world information. This paper discusses, first, an architectural solution based on Next Generation Networks: a pilot Telco Ubiquitous Sensor Network (USN) Platform that embeds several OGC® Sensor Web services. This platform has already been deployed in large scale projects. Second, the USN-Platform is extended to explore a first approach to Semantic Sensor Web principles and technologies, so that smart devices can access Sensor Web data, allowing them also to share richer (semantically interpreted) information. An experimental scenario is presented: a smart car that consumes and produces real-world information which is integrated into the Semantic Sensor Web through a Telco USN-Platform. Performance tests revealed that observation publishing times with our experimental system were well within limits compatible with the adequate operation of smart safety assistance systems in vehicles. On the other hand, response times for complex queries on large repositories may be inappropriate for rapid reaction needs. PMID:24945678

A ubiquitous sensor network platform for integrating smart devices into the semantic sensor web.

PubMed

de Vera, David Díaz Pardo; Izquierdo, Alvaro Sigüenza; Vercher, Jesús Bernat; Hernández Gómez, Luis Alfonso

2014-06-18

Ongoing Sensor Web developments make a growing amount of heterogeneous sensor data available to smart devices. This is generating an increasing demand for homogeneous mechanisms to access, publish and share real-world information. This paper discusses, first, an architectural solution based on Next Generation Networks: a pilot Telco Ubiquitous Sensor Network (USN) Platform that embeds several OGC® Sensor Web services. This platform has already been deployed in large scale projects. Second, the USN-Platform is extended to explore a first approach to Semantic Sensor Web principles and technologies, so that smart devices can access Sensor Web data, allowing them also to share richer (semantically interpreted) information. An experimental scenario is presented: a smart car that consumes and produces real-world information which is integrated into the Semantic Sensor Web through a Telco USN-Platform. Performance tests revealed that observation publishing times with our experimental system were well within limits compatible with the adequate operation of smart safety assistance systems in vehicles. On the other hand, response times for complex queries on large repositories may be inappropriate for rapid reaction needs.

Development of a home-based training program for post-ward geriatric rehabilitation patients with cognitive impairment: study protocol of a randomized-controlled trail.

PubMed

Bongartz, Martin; Kiss, Rainer; Ullrich, Phoebe; Eckert, Tobias; Bauer, Jürgen; Hauer, Klaus

2017-09-12

Geriatric patients with cognitive impairment (CI) show an increased risk for a negative rehabilitation outcome and reduced functional recovery following inpatient rehabilitation. Despite this obvious demand, evidence-based training programs at the transition from rehabilitation to the home environments are lacking. The aim of this study is to evaluate the efficacy of a feasible and cost-effective home-based training program to improve motor performance and to promote physical activity, specifically-tailored for post-ward geriatric patients with CI. A sample of 101 geriatric patients with mild to moderate stage CI following ward-based rehabilitation will be recruited for a blinded, randomized controlled trial with two arms. The intervention group will conduct a 12 week home-based training, consisting of (1) Exercises to improve strength/power, and postural control; (2) Individual walking trails to enhance physical activity; (3) Implementation of patient-specific motivational strategies to promote behavioral changes. The control group will conduct 12 weeks of unspecific flexibility exercise. Both groups will complete a baseline measurement before starting the program, at the end of the intervention, and after 24 weeks for follow-up. Sensor-based as well as questionnaire-based measures will be applied to comprehensively assess intervention effects. Primary outcomes document motor performance, assessed by the Short Physical Performance Battery, and level of physical activity (PA), as assessed by duration of active episodes (i.e., sum of standing and walking). Secondary outcomes include various medical, psycho-social, various PA and motor outcomes, including sensor-based assessment as well as cost effectiveness. Our study is among the first to provide home-based training in geriatric patients with CI at the transition from a rehabilitation unit to the home environment. The program offers several unique approaches, e.g., a comprehensive and innovative assessment strategy and the integration of individually-tailored motivational strategies. We expect the program to be safe and feasible in geriatric patients with CI with the potential to enhance the sustainability of geriatric rehabilitation programs in patients with CI. International Standard Randomized Controlled Trial (# ISRCTN82378327 ). Registered: August 10, 2015.

Advanced Networks in Dental Rich Online MEDiA (ANDROMEDA)

NASA Astrophysics Data System (ADS)

Elson, Bruce; Reynolds, Patricia; Amini, Ardavan; Burke, Ezra; Chapman, Craig

There is growing demand for dental education and training not only in terms of knowledge but also skills. This demand is driven by continuing professional development requirements in the more developed economies, personnel shortages and skills differences across the European Union (EU) accession states and more generally in the developing world. There is an excellent opportunity for the EU to meet this demand by developing an innovative online flexible learning platform (FLP). Current clinical online systems are restricted to the delivery of general, knowledge-based training with no easy method of personalization or delivery of skill-based training. The PHANTOM project, headed by Kings College London is developing haptic-based virtual reality training systems for clinical dental training. ANDROMEDA seeks to build on this and establish a Flexible Learning Platform that can integrate the haptic and sensor based training with rich media knowledge transfer, whilst using sophisticated technologies such as including service-orientated architecture (SOA), Semantic Web technologies, knowledge-based engineering, business intelligence (BI) and virtual worlds for personalization.

A Wireless Platform for Energy Efficient Building Control Retrofits

DTIC Science & Technology

2012-08-01

University of Illinois at Urbana Champaign UTRC United Technologies Research Center VFD variable frequency drive WSN wireless sensor network ...demonstration area. .............................................................. 16 Table 4. Cost model for wireless sensor network ...buildings with MPC-based whole-building optimal control and (2) reduction in first costs achievable with a wireless sensor network (WSN)-based

Inertial Sensor-Based Touch and Shake Metaphor for Expressive Control of 3D Virtual Avatars

PubMed Central

Patil, Shashidhar; Chintalapalli, Harinadha Reddy; Kim, Dubeom; Chai, Youngho

2015-01-01

In this paper, we present an inertial sensor-based touch and shake metaphor for expressive control of a 3D virtual avatar in a virtual environment. An intuitive six degrees-of-freedom wireless inertial motion sensor is used as a gesture and motion control input device with a sensor fusion algorithm. The algorithm enables user hand motions to be tracked in 3D space via magnetic, angular rate, and gravity sensors. A quaternion-based complementary filter is implemented to reduce noise and drift. An algorithm based on dynamic time-warping is developed for efficient recognition of dynamic hand gestures with real-time automatic hand gesture segmentation. Our approach enables the recognition of gestures and estimates gesture variations for continuous interaction. We demonstrate the gesture expressivity using an interactive flexible gesture mapping interface for authoring and controlling a 3D virtual avatar and its motion by tracking user dynamic hand gestures. This synthesizes stylistic variations in a 3D virtual avatar, producing motions that are not present in the motion database using hand gesture sequences from a single inertial motion sensor. PMID:26094629

Building Intrusion Detection with a Wireless Sensor Network

NASA Astrophysics Data System (ADS)

Wälchli, Markus; Braun, Torsten

This paper addresses the detection and reporting of abnormal building access with a wireless sensor network. A common office room, offering space for two working persons, has been monitored with ten sensor nodes and a base station. The task of the system is to report suspicious office occupation such as office searching by thieves. On the other hand, normal office occupation should not throw alarms. In order to save energy for communication, the system provides all nodes with some adaptive short-term memory. Thus, a set of sensor activation patterns can be temporarily learned. The local memory is implemented as an Adaptive Resonance Theory (ART) neural network. Unknown event patterns detected on sensor node level are reported to the base station, where the system-wide anomaly detection is performed. The anomaly detector is lightweight and completely self-learning. The system can be run autonomously or it could be used as a triggering system to turn on an additional high-resolution system on demand. Our building monitoring system has proven to work reliably in different evaluated scenarios. Communication costs of up to 90% could be saved compared to a threshold-based approach without local memory.

LISA technology development using the UF precision torsion pendulum

NASA Astrophysics Data System (ADS)

Apple, Stephen; Chilton, Andrew; Olatunde, Taiwo; Ciani, Giacomo; Mueller, Guido; Conklin, John

2015-04-01

LISA will directly observe low-frequency gravitational waves emitted by sources ranging from super-massive black hole mergers to compact galactic binaries. A laser interferometer will measure picometer changes in the distances between free falling test masses separated by millions of kilometers. A test mass and its associated sensing, actuation, charge control and caging subsystems are referred to as a gravitational reference sensor (GRS). The demanding acceleration noise requirement for the LISA GRS has motivated a rigorous testing campaign in Europe and a dedicated technology mission, LISA Pathfinder, scheduled for launch in the fall of 2015. At the University of Florida we are developing a nearly thermally noise limited torsion pendulum for testing GRS technology enhancements that may improve the performance and/or reduce the cost of the LISA GRS. This experimental facility is based on the design of a similar facility at the University of Trento, and consists of a vacuum enclosed torsion pendulum that suspends mock-ups of the LISA test masses, surrounded by electrode housings. Some of the technologies that will be demonstrated by this facility include a novel TM charge control scheme based on ultraviolet LEDs, an all-optical TM position and attitude sensor, and drift mode operation. This presentation will describe the design of the torsion pendulum facility, its current acceleration noise performance, and the status of the GRS technologies under development.

The need for separate operational and engineering user interfaces for command and control of airborne synthetic aperture radar systems

NASA Astrophysics Data System (ADS)

Klein, Laura M.; McNamara, Laura A.

2017-05-01

In this paper, we address the needed components to create usable engineering and operational user interfaces (UIs) for airborne Synthetic Aperture Radar (SAR) systems. As airborne SAR technology gains wider acceptance in the remote sensing and Intelligence, Surveillance, and Reconnaissance (ISR) communities, the need for effective and appropriate UIs to command and control these sensors has also increased. However, despite the growing demand for SAR in operational environments, the technology still faces an adoption roadblock, in large part due to the lack of effective UIs. It is common to find operational interfaces that have barely grown beyond the disparate tools engineers and technologists developed to demonstrate an initial concept or system. While sensor usability and utility are common requirements to engineers and operators, their objectives for interacting with the sensor are different. As such, the amount and type of information presented ought to be tailored to the specific application.

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 laser spectrometer enables multi-gas sensors with significantly increased performance over that presently offered in the EMU.

Modification and fixed-point analysis of a Kalman filter for orientation estimation based on 9D inertial measurement unit data.

PubMed

Brückner, Hans-Peter; Spindeldreier, Christian; Blume, Holger

2013-01-01

A common approach for high accuracy sensor fusion based on 9D inertial measurement unit data is Kalman filtering. State of the art floating-point filter algorithms differ in their computational complexity nevertheless, real-time operation on a low-power microcontroller at high sampling rates is not possible. This work presents algorithmic modifications to reduce the computational demands of a two-step minimum order Kalman filter. Furthermore, the required bit-width of a fixed-point filter version is explored. For evaluation real-world data captured using an Xsens MTx inertial sensor is used. Changes in computational latency and orientation estimation accuracy due to the proposed algorithmic modifications and fixed-point number representation are evaluated in detail on a variety of processing platforms enabling on-board processing on wearable sensor platforms.

Intelligent Luminance Control of Lighting Systems Based on Imaging Sensor Feedback

PubMed Central

Liu, Haoting; Zhou, Qianxiang; Yang, Jin; Jiang, Ting; Liu, Zhizhen; Li, Jie

2017-01-01

An imaging sensor-based intelligent Light Emitting Diode (LED) lighting system for desk use is proposed. In contrast to the traditional intelligent lighting system, such as the photosensitive resistance sensor-based or the infrared sensor-based system, the imaging sensor can realize a finer perception of the environmental light; thus it can guide a more precise lighting control. Before this system works, first lots of typical imaging lighting data of the desk application are accumulated. Second, a series of subjective and objective Lighting Effect Evaluation Metrics (LEEMs) are defined and assessed for these datasets above. Then the cluster benchmarks of these objective LEEMs can be obtained. Third, both a single LEEM-based control and a multiple LEEMs-based control are developed to realize a kind of optimal luminance tuning. When this system works, first it captures the lighting image using a wearable camera. Then it computes the objective LEEMs of the captured image and compares them with the cluster benchmarks of the objective LEEMs. Finally, the single LEEM-based or the multiple LEEMs-based control can be implemented to get a kind of optimal lighting effect. Many experiment results have shown the proposed system can tune the LED lamp automatically according to environment luminance changes. PMID:28208781

Intelligent Luminance Control of Lighting Systems Based on Imaging Sensor Feedback.

PubMed

Liu, Haoting; Zhou, Qianxiang; Yang, Jin; Jiang, Ting; Liu, Zhizhen; Li, Jie

2017-02-09

An imaging sensor-based intelligent Light Emitting Diode (LED) lighting system for desk use is proposed. In contrast to the traditional intelligent lighting system, such as the photosensitive resistance sensor-based or the infrared sensor-based system, the imaging sensor can realize a finer perception of the environmental light; thus it can guide a more precise lighting control. Before this system works, first lots of typical imaging lighting data of the desk application are accumulated. Second, a series of subjective and objective Lighting Effect Evaluation Metrics (LEEMs) are defined and assessed for these datasets above. Then the cluster benchmarks of these objective LEEMs can be obtained. Third, both a single LEEM-based control and a multiple LEEMs-based control are developed to realize a kind of optimal luminance tuning. When this system works, first it captures the lighting image using a wearable camera. Then it computes the objective LEEMs of the captured image and compares them with the cluster benchmarks of the objective LEEMs. Finally, the single LEEM-based or the multiple LEEMs-based control can be implemented to get a kind of optimal lighting effect. Many experiment results have shown the proposed system can tune the LED lamp automatically according to environment luminance changes.

California DREAMing: The design of residential demand responsive technology with people in mind

NASA Astrophysics Data System (ADS)

Peffer, Therese Evelyn

Electrical utilities worldwide are exploring "demand response" programs to reduce electricity consumption during peak periods. Californian electrical utilities would like to pass the higher cost of peak demand to customers to offset costs, increase reliability, and reduce peak consumption. Variable pricing strategies require technology to communicate a dynamic price to customers and respond to that price. However, evidence from thermostat and energy display studies as well as research regarding energy-saving behaviors suggests that devices cannot effect residential demand response without the sanction and participation of people. This study developed several technologies to promote or enable residential demand response. First, along with a team of students and professors, I designed and tested the Demand Response Electrical Appliance Manager (DREAM). This wireless network of sensors, actuators, and controller with a user interface provides information to intelligently control a residential heating and cooling system and to inform people of their energy usage. We tested the system with computer simulation and in the laboratory and field. Secondly, as part of my contribution to the team, I evaluated machine-learning to predict a person's seasonal temperature preferences by analyzing existing data from office workers. The third part of the research involved developing an algorithm that generated temperature setpoints based on outdoor temperature. My study compared the simulated energy use using these setpoints to that using the setpoints of a programmable thermostat. Finally, I developed and tested a user interface for a thermostat and in-home energy display. This research tested the effects of both energy versus price information and the context of sponsorship on the behavior of subjects. I also surveyed subjects on the usefulness of various displays. The wireless network succeeded in providing detailed data to enable an intelligent controller and provide feedback to the users. The learning algorithm showed mixed results. The adaptive temperature setpoints saved energy in both annual and summertime simulations. The context in which I introduced the DREAM interface affected behavior, but the type of information displayed did not. The subjects responded that appliance-level feedback and tools that provided choices would be useful in a dynamic tariff environment.

Comprehensive tire-road friction coefficient estimation based on signal fusion method under complex maneuvering operations

NASA Astrophysics Data System (ADS)

Li, L.; Yang, K.; Jia, G.; Ran, X.; Song, J.; Han, Z.-Q.

2015-05-01

The accurate estimation of the tire-road friction coefficient plays a significant role in the vehicle dynamics control. The estimation method should be timely and reliable for the controlling requirements, which means the contact friction characteristics between the tire and the road should be recognized before the interference to ensure the safety of the driver and passengers from drifting and losing control. In addition, the estimation method should be stable and feasible for complex maneuvering operations to guarantee the control performance as well. A signal fusion method combining the available signals to estimate the road friction is suggested in this paper on the basis of the estimated ones of braking, driving and steering conditions individually. Through the input characteristics and the states of the vehicle and tires from sensors the maneuvering condition may be recognized, by which the certainty factors of the friction of the three conditions mentioned above may be obtained correspondingly, and then the comprehensive road friction may be calculated. Experimental vehicle tests validate the effectiveness of the proposed method through complex maneuvering operations; the estimated road friction coefficient based on the signal fusion method is relatively timely and accurate to satisfy the control demands.

Low cost fiber optic sensing of sugar solution

NASA Astrophysics Data System (ADS)

Muthuraju, M. E.; Patlolla, Anurag Reddy; Vadakkapattu Canthadai, Badrinath; Pachava, Vengalrao

2015-03-01

The demand for highly sensitive and reliable sensors to assess the refractive index of liquid get many applications in chemical and biomedical areas. Indeed, the physical parameters such as concentration, pressure and density, etc., can be found using the refractive index of liquid. In contrast to the conventional refractometer for measurement, optical fiber sensor has several advantages like remote sensing, small in size, low cost, immune to EMI etc., In this paper we have discussed determination of refractive index of sugar solution using optical fiber. An intensity modulated low cost plastic fiber optic refractive index sensor has been designed for the study. The sensor is based on principle of change in angle of reflected light caused by refractive index change of the medium surrounding the fiber. The experimental results obtained for the sugar solution of different refractive indices prove that the fiber optic sensor is cable of measuring the refractive indices as well as the concentrations.

3D Reconfigurable MPSoC for Unmanned Spacecraft Navigation

NASA Astrophysics Data System (ADS)

Dekoulis, George

2016-07-01

This paper describes the design of a new lightweight spacecraft navigation system for unmanned space missions. The system addresses the demands for more efficient autonomous navigation in the near-Earth environment or deep space. The proposed instrumentation is directly suitable for unmanned systems operation and testing of new airborne prototypes for remote sensing applications. The system features a new sensor technology and significant improvements over existing solutions. Fluxgate type sensors have been traditionally used in unmanned defense systems such as target drones, guided missiles, rockets and satellites, however, the guidance sensors' configurations exhibit lower specifications than the presented solution. The current implementation is based on a recently developed material in a reengineered optimum sensor configuration for unprecedented low-power consumption. The new sensor's performance characteristics qualify it for spacecraft navigation applications. A major advantage of the system is the efficiency in redundancy reduction achieved in terms of both hardware and software requirements.

Low-cost photonic sensors for carbon dioxide exchange rate measurement

NASA Astrophysics Data System (ADS)

Bieda, Marcin S.; Sobotka, Piotr; Lesiak, Piotr; Woliński, Tomasz R.

2017-10-01

Carbon dioxide (CO2) measurement has an important role in atmosphere monitoring. Usually, two types of measurements are carried out. The first one is based on gas concentration measurement while the second involves gas exchange rate measurement between earth surface and atmosphere [1]. There are several methods which allow gas concentration measurement. However, most of them require expensive instrumentation or large devices (i.e. gas chambers). In order to precisely measure either CO2 concentration or CO2 exchange rate, preferably a sensors network should be used. These sensors must have small dimensions, low power consumption, and they should be cost-effective. Therefore, this creates a great demand for a robust low-power and low-cost CO2 sensor [2,3]. As a solution, we propose a photonic sensor that can measure CO2 concentration and also can be used to measure gas exchange by using the Eddy covariance method [1].

Smart Building: Decision Making Architecture for Thermal Energy Management

PubMed Central

Hernández Uribe, Oscar; San Martin, Juan Pablo; Garcia-Alegre, María C.; Santos, Matilde; Guinea, Domingo

2015-01-01

Smart applications of the Internet of Things are improving the performance of buildings, reducing energy demand. Local and smart networks, soft computing methodologies, machine intelligence algorithms and pervasive sensors are some of the basics of energy optimization strategies developed for the benefit of environmental sustainability and user comfort. This work presents a distributed sensor-processor-communication decision-making architecture to improve the acquisition, storage and transfer of thermal energy in buildings. The developed system is implemented in a near Zero-Energy Building (nZEB) prototype equipped with a built-in thermal solar collector, where optical properties are analysed; a low enthalpy geothermal accumulation system, segmented in different temperature zones; and an envelope that includes a dynamic thermal barrier. An intelligent control of this dynamic thermal barrier is applied to reduce the thermal energy demand (heating and cooling) caused by daily and seasonal weather variations. Simulations and experimental results are presented to highlight the nZEB thermal energy reduction. PMID:26528978

Fault-tolerant cooperative output regulation for multi-vehicle systems with sensor faults

NASA Astrophysics Data System (ADS)

Qin, Liguo; He, Xiao; Zhou, D. H.

2017-10-01

This paper presents a unified framework of fault diagnosis and fault-tolerant cooperative output regulation (FTCOR) for a linear discrete-time multi-vehicle system with sensor faults. The FTCOR control law is designed through three steps. A cooperative output regulation (COR) controller is designed based on the internal mode principle when there are no sensor faults. A sufficient condition on the existence of the COR controller is given based on the discrete-time algebraic Riccati equation (DARE). Then, a decentralised fault diagnosis scheme is designed to cope with sensor faults occurring in followers. A residual generator is developed to detect sensor faults of each follower, and a bank of fault-matching estimators are proposed to isolate and estimate sensor faults of each follower. Unlike the current distributed fault diagnosis for multi-vehicle systems, the presented decentralised fault diagnosis scheme in each vehicle reduces the communication and computation load by only using the information of the vehicle. By combing the sensor fault estimation and the COR control law, an FTCOR controller is proposed. Finally, the simulation results demonstrate the effectiveness of the FTCOR controller.

Multiagent Systems Based Modeling and Implementation of Dynamic Energy Management of Smart Microgrid Using MACSimJX.

PubMed

Raju, Leo; Milton, R S; Mahadevan, Senthilkumaran

The objective of this paper is implementation of multiagent system (MAS) for the advanced distributed energy management and demand side management of a solar microgrid. Initially, Java agent development environment (JADE) frame work is used to implement MAS based dynamic energy management of solar microgrid. Due to unstable nature of MATLAB, when dealing with multithreading environment, MAS operating in JADE is linked with the MATLAB using a middle ware called Multiagent Control Using Simulink with Jade Extension (MACSimJX). MACSimJX allows the solar microgrid components designed with MATLAB to be controlled by the corresponding agents of MAS. The microgrid environment variables are captured through sensors and given to agents through MATLAB/Simulink and after the agent operations in JADE, the results are given to the actuators through MATLAB for the implementation of dynamic operation in solar microgrid. MAS operating in JADE maximizes operational efficiency of solar microgrid by decentralized approach and increase in runtime efficiency due to JADE. Autonomous demand side management is implemented for optimizing the power exchange between main grid and microgrid with intermittent nature of solar power, randomness of load, and variation of noncritical load and grid price. These dynamics are considered for every time step and complex environment simulation is designed to emulate the distributed microgrid operations and evaluate the impact of agent operations.

Multiagent Systems Based Modeling and Implementation of Dynamic Energy Management of Smart Microgrid Using MACSimJX

PubMed Central

Raju, Leo; Milton, R. S.; Mahadevan, Senthilkumaran

2016-01-01

The objective of this paper is implementation of multiagent system (MAS) for the advanced distributed energy management and demand side management of a solar microgrid. Initially, Java agent development environment (JADE) frame work is used to implement MAS based dynamic energy management of solar microgrid. Due to unstable nature of MATLAB, when dealing with multithreading environment, MAS operating in JADE is linked with the MATLAB using a middle ware called Multiagent Control Using Simulink with Jade Extension (MACSimJX). MACSimJX allows the solar microgrid components designed with MATLAB to be controlled by the corresponding agents of MAS. The microgrid environment variables are captured through sensors and given to agents through MATLAB/Simulink and after the agent operations in JADE, the results are given to the actuators through MATLAB for the implementation of dynamic operation in solar microgrid. MAS operating in JADE maximizes operational efficiency of solar microgrid by decentralized approach and increase in runtime efficiency due to JADE. Autonomous demand side management is implemented for optimizing the power exchange between main grid and microgrid with intermittent nature of solar power, randomness of load, and variation of noncritical load and grid price. These dynamics are considered for every time step and complex environment simulation is designed to emulate the distributed microgrid operations and evaluate the impact of agent operations. PMID:27127802

A Micromechanical INS/GPS System for Small Satellites

NASA Technical Reports Server (NTRS)

Barbour, N.; Brand, T.; Haley, R.; Socha, M.; Stoll, J.; Ward, P.; Weinberg, M.

1995-01-01

The cost and complexity of large satellite space missions continue to escalate. To reduce costs, more attention is being directed toward small lightweight satellites where future demand is expected to grow dramatically. Specifically, micromechanical inertial systems and microstrip global positioning system (GPS) antennas incorporating flip-chip bonding, application specific integrated circuits (ASIC) and MCM technologies will be required. Traditional microsatellite pointing systems do not employ active control. Many systems allow the satellite to point coarsely using gravity gradient, then attempt to maintain the image on the focal plane with fast-steering mirrors. Draper's approach is to actively control the line of sight pointing by utilizing on-board attitude determination with micromechanical inertial sensors and reaction wheel control actuators. Draper has developed commercial and tactical-grade micromechanical inertial sensors, The small size, low weight, and low cost of these gyroscopes and accelerometers enable systems previously impractical because of size and cost. Evolving micromechanical inertial sensors can be applied to closed-loop, active control of small satellites for micro-radian precision-pointing missions. An inertial reference feedback control loop can be used to determine attitude and line of sight jitter to provide error information to the controller for correction. At low frequencies, the error signal is provided by GPS. At higher frequencies, feedback is provided by the micromechanical gyros. This blending of sensors provides wide-band sensing from dc to operational frequencies. First order simulation has shown that the performance of existing micromechanical gyros, with integrated GPS, is feasible for a pointing mission of 10 micro-radians of jitter stability and approximately 1 milli-radian absolute error, for a satellite with 1 meter antenna separation. Improved performance micromechanical sensors currently under development will be suitable for a range of micro-nano-satellite applications.

A software sensor model based on hybrid fuzzy neural network for rapid estimation water quality in Guangzhou section of Pearl River, China.

PubMed

Zhou, Chunshan; Zhang, Chao; Tian, Di; Wang, Ke; Huang, Mingzhi; Liu, Yanbiao

2018-01-02

In order to manage water resources, a software sensor model was designed to estimate water quality using a hybrid fuzzy neural network (FNN) in Guangzhou section of Pearl River, China. The software sensor system was composed of data storage module, fuzzy decision-making module, neural network module and fuzzy reasoning generator module. Fuzzy subtractive clustering was employed to capture the character of model, and optimize network architecture for enhancing network performance. The results indicate that, on basis of available on-line measured variables, the software sensor model can accurately predict water quality according to the relationship between chemical oxygen demand (COD) and dissolved oxygen (DO), pH and NH 4 + -N. Owing to its ability in recognizing time series patterns and non-linear characteristics, the software sensor-based FNN is obviously superior to the traditional neural network model, and its R (correlation coefficient), MAPE (mean absolute percentage error) and RMSE (root mean square error) are 0.8931, 10.9051 and 0.4634, respectively.

Chain-Based Communication in Cylindrical Underwater Wireless Sensor Networks

PubMed Central

Javaid, Nadeem; Jafri, Mohsin Raza; Khan, Zahoor Ali; Alrajeh, Nabil; Imran, Muhammad; Vasilakos, Athanasios

2015-01-01

Appropriate network design is very significant for Underwater Wireless Sensor Networks (UWSNs). Application-oriented UWSNs are planned to achieve certain objectives. Therefore, there is always a demand for efficient data routing schemes, which can fulfill certain requirements of application-oriented UWSNs. These networks can be of any shape, i.e., rectangular, cylindrical or square. In this paper, we propose chain-based routing schemes for application-oriented cylindrical networks and also formulate mathematical models to find a global optimum path for data transmission. In the first scheme, we devise four interconnected chains of sensor nodes to perform data communication. In the second scheme, we propose routing scheme in which two chains of sensor nodes are interconnected, whereas in third scheme single-chain based routing is done in cylindrical networks. After finding local optimum paths in separate chains, we find global optimum paths through their interconnection. Moreover, we develop a computational model for the analysis of end-to-end delay. We compare the performance of the above three proposed schemes with that of Power Efficient Gathering System in Sensor Information Systems (PEGASIS) and Congestion adjusted PEGASIS (C-PEGASIS). Simulation results show that our proposed 4-chain based scheme performs better than the other selected schemes in terms of network lifetime, end-to-end delay, path loss, transmission loss, and packet sending rate. PMID:25658394

REVIEW ARTICLE: Sensors for automotive telematics

NASA Astrophysics Data System (ADS)

Turner, J. D.; Austin, L.

2000-02-01

This article reviews the current practice in sensors and sensor applications for automotive and traffic-control systems. Sensors to control engine fuelling, ignition and transmission (known as the powertrain) are reviewed and the likely course of future development is discussed in the light of regulatory and market requirements as well as trends in sensor design and manufacture. Sensor needs for suspension, braking and control of traction are also reviewed and the likely introduction of wheel and tyre sensors to enhance driving safety is discussed. The recent trend towards vehicle-mounted devices to sense the vehicle's environment (such as radar, optical, ultrasound, capacitive and image-based systems) and the implications of the introduction of safety-critical automotive systems such as adaptive cruise control are discussed. Sensors for initiating the deployment of safety systems such as airbags, together with transducers for disconnecting fuel pumps and vehicle batteries in the event of a crash, are reviewed. The paper includes a brief discussion of highway-based sensors for measuring vehicle speed and presence and concludes with a discussion of the likely future developments in the field.

Adapting Wireless Technology to Lighting Control and Environmental Sensing

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

Dana Teasdale; Francis Rubinstein; David S. Watson

Although advanced lighting control systems offer significant energy savings, the high cost of retrofitting buildings with advanced lighting control systems is a barrier to adoption of this energy-saving technology. Wireless technology, however, offers a solution to mounting installation costs since it requires no additional wiring to implement. To demonstrate the feasibility of such a system, a prototype wirelessly-controlled advanced lighting system was designed and built. The system includes the following components: a wirelessly-controllable analog circuit module (ACM), a wirelessly-controllable electronic dimmable ballast, a T8 3-lamp fixture, an environmental multi-sensor, a current transducer, and control software. The ACM, dimmable ballast, multi-sensor,more » and current transducer were all integrated with SmartMesh{trademark} wireless mesh networking nodes, called motes, enabling wireless communication, sensor monitoring, and actuator control. Each mote-enabled device has a reliable communication path to the SmartMesh Manager, a single board computer that controls network functions and connects the wireless network to a PC running lighting control software. The ACM is capable of locally driving one or more standard 0-10 Volt electronic dimmable ballasts through relay control and a 0-10 Volt controllable output, in addition to 0-24 Volt and 0-10 Volt inputs. The mote-integrated electronic dimmable ballast is designed to drive a standard 3-lamp T8 light fixture. The environmental multisensor measures occupancy, light level and temperature. The current transducer is used to measure the power consumed by the fixture. Control software was developed to implement advanced lighting algorithms, including open and closed-loop daylight ramping, occupancy control, and demand response. Engineering prototypes of each component were fabricated and tested in a bench-scale system. Based on standard industry practices, a cost analysis was conducted. It is estimated that the installation cost of a wireless advanced lighting control system for a retrofit application is at least 20% lower than a comparable wired system for a typical 16,000 square-foot office building, with a payback period of less than 3 years. At 30% market penetration saturation, a cumulative 695 Billion kWh of energy could be saved through 2025, a cost savings of $52 Billion.« less

TANDIR: projectile warning system using uncooled bolometric technology

NASA Astrophysics Data System (ADS)

Horovitz-Limor, Z.; Zahler, M.

2007-04-01

Following the demand for affordable, various range and light-weight protection against ATGM's, Elisra develops a cost-effective passive IR system for ground vehicles. The system is based on wide FOV uncooled bolometric sensors with full azimuth coverage and a lightweight processing & control unit. The system design is based on the harsh environmental conditions. The basic algorithm discriminates the target from its clutter and predicts the time to impact (TTI) and the target aiming direction with relation to vehicle. The current detector format is 320*240 pixels and frame rate is 60 Hz, Spectral response is on Far Infrared (8-14μ). The digital video output has 14bit resolution & wide dynamic range. Future goal is to enhance detection performance by using large format uncooled detector (640X480) with improved sensitivity and higher frame rates (up to 120HZ).

Distributed Environment Control Using Wireless Sensor/Actuator Networks for Lighting Applications

PubMed Central

Nakamura, Masayuki; Sakurai, Atsushi; Nakamura, Jiro

2009-01-01

We propose a decentralized algorithm to calculate the control signals for lights in wireless sensor/actuator networks. This algorithm uses an appropriate step size in the iterative process used for quickly computing the control signals. We demonstrate the accuracy and efficiency of this approach compared with the penalty method by using Mote-based mesh sensor networks. The estimation error of the new approach is one-eighth as large as that of the penalty method with one-fifth of its computation time. In addition, we describe our sensor/actuator node for distributed lighting control based on the decentralized algorithm and demonstrate its practical efficacy. PMID:22291525

A fiber optic sensor for on-line non-touch monitoring of roll shape

NASA Astrophysics Data System (ADS)

Guo, Yuan; Qu, Weijian; Yuan, Qi

2009-07-01

Basing on the principle of reflective displacement fibre-optic sensor, a high accuracy non-touch on-line optical fibre sensor for detecting roll shape is presented. The principle and composition of the detection system and the operation process are expatiated also. By using a novel probe of three optical fibres in equal transverse space, the effects of fluctuations in the light source, reflective changing of target surface and the intensity losses in the fibre lines are automatically compensated. Meantime, an optical fibre sensor model of correcting static error based on BP artificial neural network (ANN) is set up. Also by using interpolation method and value filtering to process the signals, effectively reduce the influence of random noise and the vibration of the roll bearing. So the accuracy and resolution were enhanced remarkably. Experiment proves that the resolution is 1μm and the precision can reach to 0.1%. So the system reaches to the demand of practical production process.

Multi Sensor Fusion Using Fitness Adaptive Differential Evolution

NASA Astrophysics Data System (ADS)

Giri, Ritwik; Ghosh, Arnob; Chowdhury, Aritra; Das, Swagatam

The rising popularity of multi-source, multi-sensor networks supports real-life applications calls for an efficient and intelligent approach to information fusion. Traditional optimization techniques often fail to meet the demands. The evolutionary approach provides a valuable alternative due to its inherent parallel nature and its ability to deal with difficult problems. We present a new evolutionary approach based on a modified version of Differential Evolution (DE), called Fitness Adaptive Differential Evolution (FiADE). FiADE treats sensors in the network as distributed intelligent agents with various degrees of autonomy. Existing approaches based on intelligent agents cannot completely answer the question of how their agents could coordinate their decisions in a complex environment. The proposed approach is formulated to produce good result for the problems that are high-dimensional, highly nonlinear, and random. The proposed approach gives better result in case of optimal allocation of sensors. The performance of the proposed approach is compared with an evolutionary algorithm coordination generalized particle model (C-GPM).

A Graphene-Based Resistive Pressure Sensor with Record-High Sensitivity in a Wide Pressure Range

PubMed Central

Tian, He; Shu, Yi; Wang, Xue-Feng; Mohammad, Mohammad Ali; Bie, Zhi; Xie, Qian-Yi; Li, Cheng; Mi, Wen-Tian; Yang, Yi; Ren, Tian-Ling

2015-01-01

Pressure sensors are a key component in electronic skin (e-skin) sensing systems. Most reported resistive pressure sensors have a high sensitivity at low pressures (<5 kPa) to enable ultra-sensitive detection. However, the sensitivity drops significantly at high pressures (>5 kPa), which is inadequate for practical applications. For example, actions like a gentle touch and object manipulation have pressures below 10 kPa, and 10–100 kPa, respectively. Maintaining a high sensitivity in a wide pressure range is in great demand. Here, a flexible, wide range and ultra-sensitive resistive pressure sensor with a foam-like structure based on laser-scribed graphene (LSG) is demonstrated. Benefitting from the large spacing between graphene layers and the unique v-shaped microstructure of the LSG, the sensitivity of the pressure sensor is as high as 0.96 kPa−1 in a wide pressure range (0 ~ 50 kPa). Considering both sensitivity and pressure sensing range, the pressure sensor developed in this work is the best among all reported pressure sensors to date. A model of the LSG pressure sensor is also established, which agrees well with the experimental results. This work indicates that laser scribed flexible graphene pressure sensors could be widely used for artificial e-skin, medical-sensing, bio-sensing and many other areas. PMID:25721159

ISFET sensor evaluation and modification for seawater pH measurement

NASA Astrophysics Data System (ADS)

Martz, T. R.; Johnson, K. S.; Jannasch, H.; Coletti, L.; Barry, J.; Lovera, C.

2008-12-01

In the future, short-term cycles (daily to subannual) and long-term trends (annual and greater) in the carbonate system will be observed by autonomous sensors operating from a variety of platforms (e.g., moorings, profiling floats, AUVs, etc.). Of the four carbonate parameters, pH measurement has the longest history of development - yet robust autonomous sensing techniques remain elusive due to a catalog of technical challenges. Existing commercial sensor technologies generally do not meet the stringent demands of accuracy, long-term stability, low power, pressure tolerance, resistance to biofouling, and ease of use required by the oceanographic community. We report here on some recent advances in Ion Sensitive Field Effect Transistor (ISFET) technology that may open the door for more widespread autonomous seawater pH measurements. Much of our work has focused on applications of the Honeywell Durafet pH sensor, a product designed for industrial process control. Initial results from laboratory testing and deployments in the MBARI test tank and near shore moorings will be presented. Sensor calibration techniques will be addressed. Applications of now-available off-the-shelf sensors including shipboard underway measurement, shallow water mooring deployment, and a gas controlled seawater aquarium for pH perturbation experiments will be discussed. We hope that an ongoing collaboration between MBARI and Honeywell will result in a commercially available product, designed specifically for oceanographic applications, within the next several years.

Wire-positioning algorithm for coreless Hall array sensors in current measurement

NASA Astrophysics Data System (ADS)

Chen, Wenli; Zhang, Huaiqing; Chen, Lin; Gu, Shanyun

2018-05-01

This paper presents a scheme of circular-arrayed, coreless Hall-effect current transformers. It can satisfy the demands of wide dynamic range and bandwidth current in the distribution system, as well as the demand of AC and DC simultaneous measurements. In order to improve the signal to noise ratio (SNR) of the sensor, a wire-positioning algorithm is proposed, which can improve the measurement accuracy based on the post-processing of measurement data. The simulation results demonstrate that the maximum errors are 70%, 6.1% and 0.95% corresponding to Ampère’s circuital method, approximate positioning algorithm and precise positioning algorithm, respectively. It is obvious that the accuracy of the positioning algorithm is significantly improved when compared with that of the Ampère’s circuital method. The maximum error of the positioning algorithm is smaller in the experiment.

An Architecture for Real-Time Interpretation and Visualization of Structural Sensor Data in a Laboratory Environment

NASA Technical Reports Server (NTRS)

Doggett, William; Vazquez, Sixto

2000-01-01

A visualization system is being developed out of the need to monitor, interpret, and make decisions based on the information from several thousand sensors during experimental testing to facilitate development and validation of structural health monitoring algorithms. As an added benefit the system will enable complete real-time sensor assessment of complex test specimens. Complex structural specimens are routinely tested that have hundreds or thousands of sensors. During a test, it is impossible for a single researcher to effectively monitor all the sensors and subsequently interesting phenomena occur that are not recognized until post-test analysis. The ability to detect and alert the researcher to these unexpected phenomena as the test progresses will significantly enhance the understanding and utilization of complex test articles. Utilization is increased by the ability to halt a test when the health monitoring algorithm response is not satisfactory or when an unexpected phenomenon occurs, enabling focused investigation potentially through the installation of additional sensors. Often if the test continues, structural changes make it impossible to reproduce the conditions that exhibited the phenomena. The prohibitive time and costs associated with fabrication, sensoring, and subsequent testing of additional test articles generally makes it impossible to further investigate the phenomena. A scalable architecture is described to address the complex computational demands of structural health monitoring algorithm development and laboratory experimental test monitoring. The researcher monitors the test using a photographic quality 3D graphical model with actual sensor locations identified. In addition, researchers can quickly activate plots displaying time or load versus selected sensor response along with the expected values and predefined limits. The architecture has several key features. First, distributed dissimilar computers may be seamlessly integrated into the information flow. Second, virtual sensors may be defined that are complex functions of existing sensors or other virtual sensors. Virtual sensors represent a calculated value not directly measured by particular physical instrument. They can be used, for example, to represent the maximum difference in a range of sensors or the calculated buckling load based on the current strains. Third, the architecture enables autonomous response to preconceived events, where by the system can be configured to suspend or abort a test if a failure is detected in the load introduction system. Fourth, the architecture is designed to allow cooperative monitoring and control of the test progression from multiple stations both remote and local to the test system. To illustrate the architecture, a preliminary implementation is described monitoring the Stitched Composite Wing recently tested at LaRC.

Micro-controller based air pressure monitoring instrumentation system using optical fibers as sensor

NASA Astrophysics Data System (ADS)

Hazarika, D.; Pegu, D. S.

2013-03-01

This paper describes a micro-controller based instrumentation system to monitor air pressure using optical fiber sensors. The principle of macrobending is used to develop the sensor system. The instrumentation system consists of a laser source, a beam splitter, two multi mode optical fibers, two Light Dependent Resistance (LDR) based timer circuits and a AT89S8252 micro-controller. The beam splitter is used to divide the laser beam into two parts and then these two beams are launched into two multi mode fibers. One of the multi mode fibers is used as the sensor fiber and the other one is used as the reference fiber. The use of the reference fiber is to eliminate the environmental effects while measuring the air pressure magnitude. The laser beams from the sensor and reference fibers are applied to two identical LDR based timer circuits. The LDR based timer circuits are interfaced to a micro-controller through its counter pins. The micro-controller samples the frequencies of the timer circuits using its counter-0 and counter-1 and the counter values are then processed to provide the measure of air pressure magnitude.

Towards a Software Framework to Support Deployment of Low Cost End-to-End Hydroclimatological Sensor Network

NASA Astrophysics Data System (ADS)

Celicourt, P.; Piasecki, M.

2015-12-01

Deployment of environmental sensors assemblies based on cheap platforms such as Raspberry Pi and Arduino have gained much attention over the past few years. While they are more attractive due to their ability to be controlled with a few programming language choices, the configuration task can become quite complex due to the need of having to learn several different proprietary data formats and protocols which constitute a bottleneck for the expansion of sensor network. In response to this rising complexity the Institute of Electrical and Electronics Engineers (IEEE) has sponsored the development of the IEEE 1451 standard in an attempt to introduce a common standard. The most innovative concept of the standard is the Transducer Electronic Data Sheet (TEDS) which enables transducers to self-identify, self-describe, self-calibrate, to exhibit plug-and-play functionality, etc. We used Python to develop an IEEE 1451.0 platform-independent graphical user interface to generate and provide sufficient information about almost ANY sensor and sensor platforms for sensor programming purposes, automatic calibration of sensors data, incorporation of back-end demands on data management in TEDS for automatic standard-based data storage, search and discovery purposes. These features are paramount to make data management much less onerous in large scale sensor network. Along with the TEDS Creator, we developed a tool namely HydroUnits for three specific purposes: encoding of physical units in the TEDS, dimensional analysis, and on-the-fly conversion of time series allowing users to retrieve data in a desired equivalent unit while accommodating unforeseen and user-defined units. In addition, our back-end data management comprises the Python/Django equivalent of the CUAHSI Observations Data Model (ODM) namely DjangODM that will be hosted by a MongoDB Database Server which offers more convenience for our application. We are also developing a data which will be paired with the data autoloading capability of Django and a TEDS processing script to populate the database with the incoming data. The Python WaterOneFlow Web Services developed by the Texas Water Development Board will be used to publish the data. The software suite is being tested on the Raspberry Pi as end node and a laptop PC as the base station in a wireless setting.

Monitoring and Control Interface Based on Virtual Sensors

PubMed Central

Escobar, Ricardo F.; Adam-Medina, Manuel; García-Beltrán, Carlos D.; Olivares-Peregrino, Víctor H.; Juárez-Romero, David; Guerrero-Ramírez, Gerardo V.

2014-01-01

In this article, a toolbox based on a monitoring and control interface (MCI) is presented and applied in a heat exchanger. The MCI was programed in order to realize sensor fault detection and isolation and fault tolerance using virtual sensors. The virtual sensors were designed from model-based high-gain observers. To develop the control task, different kinds of control laws were included in the monitoring and control interface. These control laws are PID, MPC and a non-linear model-based control law. The MCI helps to maintain the heat exchanger under operation, even if a temperature outlet sensor fault occurs; in the case of outlet temperature sensor failure, the MCI will display an alarm. The monitoring and control interface is used as a practical tool to support electronic engineering students with heat transfer and control concepts to be applied in a double-pipe heat exchanger pilot plant. The method aims to teach the students through the observation and manipulation of the main variables of the process and by the interaction with the monitoring and control interface (MCI) developed in LabVIEW©. The MCI provides the electronic engineering students with the knowledge of heat exchanger behavior, since the interface is provided with a thermodynamic model that approximates the temperatures and the physical properties of the fluid (density and heat capacity). An advantage of the interface is the easy manipulation of the actuator for an automatic or manual operation. Another advantage of the monitoring and control interface is that all algorithms can be manipulated and modified by the users. PMID:25365462

Three-Axis Attitude Estimation With a High-Bandwidth Angular Rate Sensor

NASA Technical Reports Server (NTRS)

Bayard, David S.; Green, Joseph J.

2013-01-01

A continuing challenge for modern instrument pointing control systems is to meet the increasingly stringent pointing performance requirements imposed by emerging advanced scientific, defense, and civilian payloads. Instruments such as adaptive optics telescopes, space interferometers, and optical communications make unprecedented demands on precision pointing capabilities. A cost-effective method was developed for increasing the pointing performance for this class of NASA applications. The solution was to develop an attitude estimator that fuses star tracker and gyro measurements with a high-bandwidth angular rotation sensor (ARS). An ARS is a rate sensor whose bandwidth extends well beyond that of the gyro, typically up to 1,000 Hz or higher. The most promising ARS sensor technology is based on a magnetohydrodynamic concept, and has recently become available commercially. The key idea is that the sensor fusion of the star tracker, gyro, and ARS provides a high-bandwidth attitude estimate suitable for supporting pointing control with a fast-steering mirror or other type of tip/tilt correction for increased performance. The ARS is relatively inexpensive and can be bolted directly next to the gyro and star tracker on the spacecraft bus. The high-bandwidth attitude estimator fuses an ARS sensor with a standard three-axis suite comprised of a gyro and star tracker. The estimation architecture is based on a dual-complementary filter (DCF) structure. The DCF takes a frequency- weighted combination of the sensors such that each sensor is most heavily weighted in a frequency region where it has the lowest noise. An important property of the DCF is that it avoids the need to model disturbance torques in the filter mechanization. This is important because the disturbance torques are generally not known in applications. This property represents an advantage over the prior art because it overcomes a weakness of the Kalman filter that arises when fusing more than one rate measurement. An additional advantage over prior art is that, computationally, the DCF requires significantly fewer real-time calculations than a Kalman filter formulation. There are essentially two reasons for this: the DCF state is not augmented with angular rate, and measurement updates occur at the slower gyro rate instead of the faster ARS sampling rate. Finally, the DCF has a simple and compelling architecture. The DCF is exactly equivalent to flying two identical attitude observers, one at low rate and one at high rate. These attitude observers are exactly of the form currently flown on typical three-axis spacecraft.

Sensors and Clinical Mastitis—The Quest for the Perfect Alert

PubMed Central

Hogeveen, Henk; Kamphuis, Claudia; Steeneveld, Wilma; Mollenhorst, Herman

2010-01-01

When cows on dairy farms are milked with an automatic milking system or in high capacity milking parlors, clinical mastitis (CM) cannot be adequately detected without sensors. The objective of this paper is to describe the performance demands of sensor systems to detect CM and evaluats the current performance of these sensor systems. Several detection models based on different sensors were studied in the past. When evaluating these models, three factors are important: performance (in terms of sensitivity and specificity), the time window and the similarity of the study data with real farm data. A CM detection system should offer at least a sensitivity of 80% and a specificity of 99%. The time window should not be longer than 48 hours and study circumstances should be as similar to practical farm circumstances as possible. The study design should comprise more than one farm for data collection. Since 1992, 16 peer-reviewed papers have been published with a description and evaluation of CM detection models. There is a large variation in the use of sensors and algorithms. All this makes these results not very comparable. There is a also large difference in performance between the detection models and also a large variation in time windows used and little similarity between study data. Therefore, it is difficult to compare the overall performance of the different CM detection models. The sensitivity and specificity found in the different studies could, for a large part, be explained in differences in the used time window. None of the described studies satisfied the demands for CM detection models. PMID:22163637

Sensors and clinical mastitis--the quest for the perfect alert.

PubMed

Hogeveen, Henk; Kamphuis, Claudia; Steeneveld, Wilma; Mollenhorst, Herman

2010-01-01

When cows on dairy farms are milked with an automatic milking system or in high capacity milking parlors, clinical mastitis (CM) cannot be adequately detected without sensors. The objective of this paper is to describe the performance demands of sensor systems to detect CM and evaluats the current performance of these sensor systems. Several detection models based on different sensors were studied in the past. When evaluating these models, three factors are important: performance (in terms of sensitivity and specificity), the time window and the similarity of the study data with real farm data. A CM detection system should offer at least a sensitivity of 80% and a specificity of 99%. The time window should not be longer than 48 hours and study circumstances should be as similar to practical farm circumstances as possible. The study design should comprise more than one farm for data collection. Since 1992, 16 peer-reviewed papers have been published with a description and evaluation of CM detection models. There is a large variation in the use of sensors and algorithms. All this makes these results not very comparable. There is a also large difference in performance between the detection models and also a large variation in time windows used and little similarity between study data. Therefore, it is difficult to compare the overall performance of the different CM detection models. The sensitivity and specificity found in the different studies could, for a large part, be explained in differences in the used time window. None of the described studies satisfied the demands for CM detection models.

A smart indoor air quality sensor network

NASA Astrophysics Data System (ADS)

Wen, Jin

2006-03-01

The indoor air quality (IAQ) has an important impact on public health. Currently, the indoor air pollution, caused by gas, particle, and bio-aerosol pollutants, is considered as the top five environmental risks to public health and has an estimated cost of $2 billion/year due to medical cost and lost productivity. Furthermore, current buildings are especially vulnerable for chemical and biological warfare (CBW) agent contamination because the central air conditioning and ventilation system serve as a nature carrier to spread the released agent from one location to the whole indoor environment within a short time period. To assure the IAQ and safety for either new or existing buildings, real time comprehensive IAQ and CBW measurements are needed. With the development of new sensing technologies, economic and reliable comprehensive IAQ and CBW sensors become promising. However, few studies exist that examine the design and evaluation issues related to IAQ and CBW sensor network. In this paper, relevant research areas including IAQ and CBW sensor development, demand control ventilation, indoor CBW sensor system design, and sensor system design for other areas such as water system protection, fault detection and diagnosis, are reviewed and summarized. Potential research opportunities for IAQ and CBW sensor system design and evaluation are discussed.

Use of Local Intelligence to Reduce Energy Consumption of Wireless Sensor Nodes in Elderly Health Monitoring Systems

PubMed Central

Lampoltshammer, Thomas J.; de Freitas, Edison Pignaton; Nowotny, Thomas; Plank, Stefan; da Costa, João Paulo Carvalho Lustosa; Larsson, Tony; Heistracher, Thomas

2014-01-01

The percentage of elderly people in European countries is increasing. Such conjuncture affects socio-economic structures and creates demands for resourceful solutions, such as Ambient Assisted Living (AAL), which is a possible methodology to foster health care for elderly people. In this context, sensor-based devices play a leading role in surveying, e.g., health conditions of elderly people, to alert care personnel in case of an incident. However, the adoption of such devices strongly depends on the comfort of wearing the devices. In most cases, the bottleneck is the battery lifetime, which impacts the effectiveness of the system. In this paper we propose an approach to reduce the energy consumption of sensors' by use of local sensors' intelligence. By increasing the intelligence of the sensor node, a substantial decrease in the necessary communication payload can be achieved. The results show a significant potential to preserve energy and decrease the actual size of the sensor device units. PMID:24618777

The quality of our drinking water: aluminium determination with an acoustic wave sensor.

PubMed

Veríssimo, Marta I S; Gomes, M Teresa S R

2008-06-09

A new methodology based on an inexpensive aluminium acoustic wave sensor is presented. Although the aluminium sensor has already been reported, and the composition of the selective membrane is known, the low detection limits required for the analysis of drinking water, demanded the inclusion of a preconcentration stage, as well as an optimization of the sensor. The necessary coating amount was established, as well as the best preconcentration protocol, in terms of oxidation of organic matter and aluminium elution from the Chelex-100. The methodology developed with the acoustic wave sensor allowed aluminium quantitation above 0.07 mg L(-1). Several water samples from Portugal were analysed using the acoustic wave sensor, as well as by UV-vis spectrophotometry. Results obtained with both methodologies were not statistically different (alpha=0.05), both in terms of accuracy and precision. This new methodology proved to be adequate for aluminium quantitation in drinking water and showed to be faster and less reagent consuming than the UV spectrophotometric methodology.

Use of local intelligence to reduce energy consumption of wireless sensor nodes in elderly health monitoring systems.

PubMed

Lampoltshammer, Thomas J; Pignaton de Freitas, Edison; Nowotny, Thomas; Plank, Stefan; da Costa, João Paulo Carvalho Lustosa; Larsson, Tony; Heistracher, Thomas

2014-03-11

The percentage of elderly people in European countries is increasing. Such conjuncture affects socio-economic structures and creates demands for resourceful solutions, such as Ambient Assisted Living (AAL), which is a possible methodology to foster health care for elderly people. In this context, sensor-based devices play a leading role in surveying, e.g., health conditions of elderly people, to alert care personnel in case of an incident. However, the adoption of such devices strongly depends on the comfort of wearing the devices. In most cases, the bottleneck is the battery lifetime, which impacts the effectiveness of the system. In this paper we propose an approach to reduce the energy consumption of sensors' by use of local sensors' intelligence. By increasing the intelligence of the sensor node, a substantial decrease in the necessary communication payload can be achieved. The results show a significant potential to preserve energy and decrease the actual size of the sensor device units.

Base Stock Policy in a Join-Type Production Line with Advanced Demand Information

NASA Astrophysics Data System (ADS)

Hiraiwa, Mikihiko; Tsubouchi, Satoshi; Nakade, Koichi

Production control such as the base stock policy, the kanban policy and the constant work-in-process policy in a serial production line has been studied by many researchers. Production lines, however, usually have fork-type, join-type or network-type figures. In addition, in most previous studies on production control, a finished product is required at the same time as arrival of demand at the system. Demand information is, however, informed before due date in practice. In this paper a join-type (assembly) production line under base stock control with advanced demand information in discrete time is analyzed. The recursive equations for the work-in-process are derived. The heuristic algorithm for finding appropriate base stock levels of all machines at short time is proposed and the effect of advanced demand information is examined by simulation with the proposed algorithm. It is shown that the inventory cost can decreases with little backlogs by using the appropriate amount of demand information and setting appropriate base stock levels.

Web-Based Interface for Command and Control of Network Sensors

NASA Technical Reports Server (NTRS)

Wallick, Michael N.; Doubleday, Joshua R.; Shams, Khawaja S.

2010-01-01

This software allows for the visualization and control of a network of sensors through a Web browser interface. It is currently being deployed for a network of sensors monitoring Mt. Saint Helen s volcano; however, this innovation is generic enough that it can be deployed for any type of sensor Web. From this interface, the user is able to fully control and monitor the sensor Web. This includes, but is not limited to, sending "test" commands to individual sensors in the network, monitoring for real-world events, and reacting to those events

Real-Time Wireless Data Acquisition System

NASA Technical Reports Server (NTRS)

Valencia, Emilio J.; Perotti, Jose; Lucena, Angel; Mata, Carlos

2007-01-01

Current and future aerospace requirements demand the creation of a new breed of sensing devices, with emphasis on reduced weight, power consumption, and physical size. This new generation of sensors must possess a high degree of intelligence to provide critical data efficiently and in real-time. Intelligence will include self-calibration, self-health assessment, and pre-processing of raw data at the sensor level. Most of these features are already incorporated in the Wireless Sensors Network (SensorNet(TradeMark)), developed by the Instrumentation Group at Kennedy Space Center (KSC). A system based on the SensorNet(TradeMark) architecture consists of data collection point(s) called Central Stations (CS) and intelligent sensors called Remote Stations (RS) where one or more CSs can be accommodated depending on the specific application. The CS's major function is to establish communications with the Remote Stations and to poll each RS for data and health information. The CS also collects, stores and distributes these data to the appropriate systems requiring the information. The system has the ability to perform point-to-point, multi-point and relay mode communications with an autonomous self-diagnosis of each communications link. Upon detection of a communication failure, the system automatically reconfigures to establish new communication paths. These communication paths are automatically and autonomously selected as the best paths by the system based on the existing operating environment. The data acquisition system currently under development at KSC consists of the SensorNet(TradeMark) wireless sensors as the remote stations and the central station called the Radio Frequency Health Node (RFHN). The RFF1N is the central station which remotely communicates with the SensorNet(TradeMark) sensors to control them and to receive data. The system's salient feature is the ability to provide deterministic sensor data with accurate time stamps for both time critical and non-time critical applications. Current wireless standards such as Zigbee(TradeMark) and Bluetooth(Registered TradeMark) do not have these capabilities and can not meet the needs that are provided by the SensorNet technology. Additionally, the system has the ability to automatically reconfigure the wireless communication link to a secondary frequency if interference is encountered and can autonomously search for a sensor that was perceived to be lost using the relay capabilities of the sensors and the secondary frequency. The RFHN and the SensorNet designs are based on modular architectures that allow for future increases in capability and the ability to expand or upgrade with relative ease. The RFHN and SensorNet sensors .can also perform data processing which forms a distributed processing architecture allowing the system to pass along information rather than just sending "raw data points" to the next higher level system. With a relatively small size, weight and power consumption, this system has the potential for both spacecraft and aircraft applications as well as ground applications that require time critical data.

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

Kim, Woohyun; Katipamula, Srinivas; Lutes, Robert G.

This report describes how the intelligent load control (ILC) algorithm can be implemented to achieve peak demand reduction while minimizing impacts on occupant comfort. The algorithm was designed to minimize the additional sensors and minimum configuration requirements to enable a scalable and cost-effective implementation for both large and small-/medium-sized commercial buildings. The ILC algorithm uses an analytic hierarchy process (AHP) to dynamically prioritize the available curtailable loads based on both quantitative (deviation of zone conditions from set point) and qualitative rules (types of zone). Although the ILC algorithm described in this report was highly tailored to work with rooftop units,more » it can be generalized for application to other building loads such as variable-air-volume (VAV) boxes and lighting systems.« less

Thermostatic system of sensor in NIR spectrometer based on PID control

NASA Astrophysics Data System (ADS)

Wang, Zhihong; Qiao, Liwei; Ji, Xufei

2016-11-01

Aiming at the shortcomings of the primary sensor thermostatic control system in the near infrared (NIR) spectrometer, a novel thermostatic control system based on proportional-integral-derivative (PID) control technology was developed to improve the detection precision of the NIR spectrometer. There were five parts including bridge amplifier circuit, analog-digital conversion (ADC) circuit, microcontroller, digital-analog conversion (DAC) circuit and drive circuit in the system. The five parts formed a closed-loop control system based on PID algorithm that was used to control the error between the temperature calculated by the sampling data of ADC and the designed temperature to ensure the stability of the spectrometer's sensor. The experimental results show that, when the operating temperature of sensor is -11°, compared with the original system, the temperature control precision of the new control system is improved from ±0.64° to ±0.04° and the spectrum signal to noise ratio (SNR) is improved from 4891 to 5967.

Observability-Based Guidance and Sensor Placement

NASA Astrophysics Data System (ADS)

Hinson, Brian T.

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

On-Demand Sensor Node Wake-Up Using Solar Panels and Visible Light Communication

PubMed Central

Carrascal, Carolina; Demirkol, Ilker; Paradells, Josep

2016-01-01

To significantly reduce, or eliminate completely, the energy waste caused by the standby (idle) mode of wireless sensor nodes, we propose a novel on-demand wake-up system, which allows the nodes to be put into sleep mode unless their activation is truly necessary. Although there have been many studies proposing RF-based wake-up radio systems, in this work, we develop the first visible light communication (VLC)-based wake-up system. The developed system can extend the existing VLC systems and can be exploited to derive new application areas such as VLC tags. The system uses an off-the-shell indoor solar panel as receptor device of the wake-up signal as well as for energy harvesting purposes, through which it is able to harvest enough energy for its autonomous work. The design, implementation details and the experimental evaluation results are presented, which include flickering characterization and wake-up range evaluations. The results show that the developed system achieve reasonable wake-up distances for indoor environments, mainly where the use of VLC systems are considered. PMID:27011190

On-Demand Sensor Node Wake-Up Using Solar Panels and Visible Light Communication.

PubMed

Carrascal, Carolina; Demirkol, Ilker; Paradells, Josep

2016-03-22

To significantly reduce, or eliminate completely, the energy waste caused by the standby (idle) mode of wireless sensor nodes, we propose a novel on-demand wake-up system, which allows the nodes to be put into sleep mode unless their activation is truly necessary. Although there have been many studies proposing RF-based wake-up radio systems, in this work, we develop the first visible light communication (VLC)-based wake-up system. The developed system can extend the existing VLC systems and can be exploited to derive new application areas such as VLC tags. The system uses an off-the-shell indoor solar panel as receptor device of the wake-up signal as well as for energy harvesting purposes, through which it is able to harvest enough energy for its autonomous work. The design, implementation details and the experimental evaluation results are presented, which include flickering characterization and wake-up range evaluations. The results show that the developed system achieve reasonable wake-up distances for indoor environments, mainly where the use of VLC systems are considered.

The Effect of the Demand Control and Effort Reward Imbalance Models on the Academic Burnout of Korean Adolescents

ERIC Educational Resources Information Center

Lee, Jayoung; Puig, Ana; Lee, Sang Min

2012-01-01

The purpose of this study was to examine the effects of the Demand Control Model (DCM) and the Effort Reward Imbalance Model (ERIM) on academic burnout for Korean students. Specifically, this study identified the effects of the predictor variables based on DCM and ERIM (i.e., demand, control, effort, reward, Demand Control Ratio, Effort Reward…

An Investigation of the Dynamic Response of a Seismically Stable Platform

DTIC Science & Technology

1982-08-01

PAD. The controls on the -9system are of two types. A low frequency tilt control, with a 10 arc second sensitivity, 2-axis tiltmeter as sensor ...Inertial Sensors Structural Analysis Holloman AFB, NiM. Support to this effort includes structural analyses toward active servo frequency band. This report...controlled to maintain a null position of a sensitive height sensor . The 6-degree-of- freedom high frequency controls are based on seismometers as sensors

Automatic and robust extrinsic camera calibration for high-accuracy mobile mapping

NASA Astrophysics Data System (ADS)

Goeman, Werner; Douterloigne, Koen; Bogaert, Peter; Pires, Rui; Gautama, Sidharta

2012-10-01

A mobile mapping system (MMS) is the answer of the geoinformation community to the exponentially growing demand for various geospatial data with increasingly higher accuracies and captured by multiple sensors. As the mobile mapping technology is pushed to explore its use for various applications on water, rail, or road, the need emerges to have an external sensor calibration procedure which is portable, fast and easy to perform. This way, sensors can be mounted and demounted depending on the application requirements without the need for time consuming calibration procedures. A new methodology is presented to provide a high quality external calibration of cameras which is automatic, robust and fool proof.The MMS uses an Applanix POSLV420, which is a tightly coupled GPS/INS positioning system. The cameras used are Point Grey color video cameras synchronized with the GPS/INS system. The method uses a portable, standard ranging pole which needs to be positioned on a known ground control point. For calibration a well studied absolute orientation problem needs to be solved. Here, a mutual information based image registration technique is studied for automatic alignment of the ranging pole. Finally, a few benchmarking tests are done under various lighting conditions which proves the methodology's robustness, by showing high absolute stereo measurement accuracies of a few centimeters.

Flexible Graphene-Based Wearable Gas and Chemical Sensors.

PubMed

Singh, Eric; Meyyappan, M; Nalwa, Hari Singh

2017-10-11

Wearable electronics is expected to be one of the most active research areas in the next decade; therefore, nanomaterials possessing high carrier mobility, optical transparency, mechanical robustness and flexibility, lightweight, and environmental stability will be in immense demand. Graphene is one of the nanomaterials that fulfill all these requirements, along with other inherently unique properties and convenience to fabricate into different morphological nanostructures, from atomically thin single layers to nanoribbons. Graphene-based materials have also been investigated in sensor technologies, from chemical sensing to detection of cancer biomarkers. The progress of graphene-based flexible gas and chemical sensors in terms of material preparation, sensor fabrication, and their performance are reviewed here. The article provides a brief introduction to graphene-based materials and their potential applications in flexible and stretchable wearable electronic devices. The role of graphene in fabricating flexible gas sensors for the detection of various hazardous gases, including nitrogen dioxide (NO 2 ), ammonia (NH 3 ), hydrogen (H 2 ), hydrogen sulfide (H 2 S), carbon dioxide (CO 2 ), sulfur dioxide (SO 2 ), and humidity in wearable technology, is discussed. In addition, applications of graphene-based materials are also summarized in detecting toxic heavy metal ions (Cd, Hg, Pb, Cr, Fe, Ni, Co, Cu, Ag), and volatile organic compounds (VOCs) including nitrobenzene, toluene, acetone, formaldehyde, amines, phenols, bisphenol A (BPA), explosives, chemical warfare agents, and environmental pollutants. The sensitivity, selectivity and strategies for excluding interferents are also discussed for graphene-based gas and chemical sensors. The challenges for developing future generation of flexible and stretchable sensors for wearable technology that would be usable for the Internet of Things (IoT) are also highlighted.

Decentralized real-time simulation of forest machines

NASA Astrophysics Data System (ADS)

Freund, Eckhard; Adam, Frank; Hoffmann, Katharina; Rossmann, Juergen; Kraemer, Michael; Schluse, Michael

2000-10-01

To develop realistic forest machine simulators is a demanding task. A useful simulator has to provide a close- to-reality simulation of the forest environment as well as the simulation of the physics of the vehicle. Customers demand a highly realistic three dimensional forestry landscape and the realistic simulation of the complex motion of the vehicle even in rough terrain in order to be able to use the simulator for operator training under close-to- reality conditions. The realistic simulation of the vehicle, especially with the driver's seat mounted on a motion platform, greatly improves the effect of immersion into the virtual reality of a simulated forest and the achievable level of education of the driver. Thus, the connection of the real control devices of forest machines to the simulation system has to be supported, i.e. the real control devices like the joysticks or the board computer system to control the crane, the aggregate etc. Beyond, the fusion of the board computer system and the simulation system is realized by means of sensors, i.e. digital and analog signals. The decentralized system structure allows several virtual reality systems to evaluate and visualize the information of the control devices and the sensors. So, while the driver is practicing, the instructor can immerse into the same virtual forest to monitor the session from his own viewpoint. In this paper, we are describing the realized structure as well as the necessary software and hardware components and application experiences.

An implantable myoelectric sensor based prosthesis control system.

PubMed

DeMichele, Glenn A; Troyk, Philip R; Kerns, Douglas A; Weir, Richard

2006-01-01

We present progress on the design and testing of an upper-extremity prosthesis control system based on implantable myoelectric sensors. The implant consists of a single silicon chip packaged with transmit and receive coils. Forward control telemetry to, and reverse EMG data telemetry from multiple implants has been demonstrated.

Testing the pyramid truth wavefront sensor for NFIRAOS in the lab

NASA Astrophysics Data System (ADS)

Mieda, Etsuko; Rosensteiner, Matthias; van Kooten, Maaike; Veran, Jean-Pierre; Lardiere, Olivier; Herriot, Glen

2016-07-01

For today and future adaptive optics observations, sodium laser guide stars (LGSs) are crucial; however, the LGS elongation problem due to the sodium layer has to be compensated, in particular for extremely large telescopes. In this paper, we describe the concept of truth wavefront sensing as a solution and present its design using a pyramid wavefront sensor (PWFS) to improve NFIRAOS (Narrow Field InfraRed Adaptive Optics System), the first light adaptive optics system for Thirty Meter Telescope. We simulate and test the truth wavefront sensor function under a controlled environment using the HeNOS (Herzberg NFIRAOS Optical Simulator) bench, a scaled-down NFIRAOS bench at NRC-Herzberg. We also touch on alternative pyramid component options because despite recent high demands for PWFSs, we suffer from the lack of pyramid supplies due to engineering difficulties.

Converging Redundant Sensor Network Information for Improved Building Control

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

Dale Tiller; D. Phil; Gregor Henze

2007-09-30

This project investigated the development and application of sensor networks to enhance building energy management and security. Commercial, industrial and residential buildings often incorporate systems used to determine occupancy, but current sensor technology and control algorithms limit the effectiveness of these systems. For example, most of these systems rely on single monitoring points to detect occupancy, when more than one monitoring point could improve system performance. Phase I of the project focused on instrumentation and data collection. During the initial project phase, a new occupancy detection system was developed, commissioned and installed in a sample of private offices and open-planmore » office workstations. Data acquisition systems were developed and deployed to collect data on space occupancy profiles. Phase II of the project demonstrated that a network of several sensors provides a more accurate measure of occupancy than is possible using systems based on single monitoring points. This phase also established that analysis algorithms could be applied to the sensor network data stream to improve the accuracy of system performance in energy management and security applications. In Phase III of the project, the sensor network from Phase I was complemented by a control strategy developed based on the results from the first two project phases: this controller was implemented in a small sample of work areas, and applied to lighting control. Two additional technologies were developed in the course of completing the project. A prototype web-based display that portrays the current status of each detector in a sensor network monitoring building occupancy was designed and implemented. A new capability that enables occupancy sensors in a sensor network to dynamically set the 'time delay' interval based on ongoing occupant behavior in the space was also designed and implemented.« less

Yeast Based Sensors

NASA Astrophysics Data System (ADS)

Shimomura-Shimizu, Mifumi; Karube, Isao

Since the first microbial cell sensor was studied by Karube et al. in 1977, many types of yeast based sensors have been developed as analytical tools. Yeasts are known as facultative anaerobes. Facultative anaerobes can survive in both aerobic and anaerobic conditions. The yeast based sensor consisted of a DO electrode and an immobilized omnivorous yeast. In yeast based sensor development, many kinds of yeast have been employed by applying their characteristics to adapt to the analyte. For example, Trichosporon cutaneum was used to estimate organic pollution in industrial wastewater. Yeast based sensors are suitable for online control of biochemical processes and for environmental monitoring. In this review, principles and applications of yeast based sensors are summarized.

Recent progress on gas sensor based on quantum cascade lasers and hollow fiber waveguides

NASA Astrophysics Data System (ADS)

Liu, Ningwu; Sun, Juan; Deng, Hao; Ding, Junya; Zhang, Lei; Li, Jingsong

2017-02-01

Mid-infrared laser spectroscopy provides an ideal platform for trace gas sensing applications. Despite this potential, early MIR sensing applications were limited due to the size of the involved optical components, e.g. light sources and sample cells. A potential solution to this demand is the integration of hollow fiber waveguide with novelty quantum cascade lasers.Recently QCLs had great improvements in power, efficiency and wavelength range, which made the miniaturized platforms for gas sensing maintaining or even enhancing the achievable sensitivity conceivable. So that the miniaturization of QCLs and HWGs can be evolved into a mini sensor, which may be tailored to a variety of real-time and in situ applications ranging from environmental monitoring to workplace safety surveillance. In this article, we introduce QCLs and HWGs, display the applications of HWG based on QCL gas sensing and discuss future strategies for hollow fiber coupled quantum cascade laser gas sensor technology.

A Fully Transparent Flexible Sensor for Cryogenic Temperatures Based on High Strength Metallurgical Graphene

PubMed Central

Pawlak, Ryszard; Lebioda, Marcin; Rymaszewski, Jacek; Szymanski, Witold; Kolodziejczyk, Lukasz; Kula, Piotr

2016-01-01

Low-temperature electronics operating in below zero temperatures or even below the lower limit of the common −65 to 125 °C temperature range are essential in medical diagnostics, in space exploration and aviation, in processing and storage of food and mainly in scientific research, like superconducting materials engineering and their applications—superconducting magnets, superconducting energy storage, and magnetic levitation systems. Such electronic devices demand special approach to the materials used in passive elements and sensors. The main goal of this work was the implementation of a fully transparent, flexible cryogenic temperature sensor with graphene structures as sensing element. Electrodes were made of transparent ITO (Indium Tin Oxide) or ITO/Ag/ITO conductive layers by laser ablation and finally encapsulated in a polymer coating. A helium closed-cycle cryostat has been used in measurements of the electrical properties of these graphene-based temperature sensors under cryogenic conditions. The sensors were repeatedly cooled from room temperature to cryogenic temperature. Graphene structures were characterized using Raman spectroscopy. The observation of the resistance changes as a function of temperature indicates the potential use of graphene layers in the construction of temperature sensors. The temperature characteristics of the analyzed graphene sensors exhibit no clear anomalies or strong non-linearity in the entire studied temperature range (as compared to the typical carbon sensor). PMID:28036036

A Fully Transparent Flexible Sensor for Cryogenic Temperatures Based on High Strength Metallurgical Graphene.

PubMed

Pawlak, Ryszard; Lebioda, Marcin; Rymaszewski, Jacek; Szymanski, Witold; Kolodziejczyk, Lukasz; Kula, Piotr

2016-12-28

Low-temperature electronics operating in below zero temperatures or even below the lower limit of the common -65 to 125 °C temperature range are essential in medical diagnostics, in space exploration and aviation, in processing and storage of food and mainly in scientific research, like superconducting materials engineering and their applications-superconducting magnets, superconducting energy storage, and magnetic levitation systems. Such electronic devices demand special approach to the materials used in passive elements and sensors. The main goal of this work was the implementation of a fully transparent, flexible cryogenic temperature sensor with graphene structures as sensing element. Electrodes were made of transparent ITO (Indium Tin Oxide) or ITO/Ag/ITO conductive layers by laser ablation and finally encapsulated in a polymer coating. A helium closed-cycle cryostat has been used in measurements of the electrical properties of these graphene-based temperature sensors under cryogenic conditions. The sensors were repeatedly cooled from room temperature to cryogenic temperature. Graphene structures were characterized using Raman spectroscopy. The observation of the resistance changes as a function of temperature indicates the potential use of graphene layers in the construction of temperature sensors. The temperature characteristics of the analyzed graphene sensors exhibit no clear anomalies or strong non-linearity in the entire studied temperature range (as compared to the typical carbon sensor).

Electronic ferroelectricity in carbon-based systems: from reality of organic conductors to promises of polymers and graphene nano-ribbons

NASA Astrophysics Data System (ADS)

Kirova, Natasha; Brazovskii, Serguei

2014-03-01

Ferroelectricity is a rising demand in fundamental and applied solid state physics. Ferroelectrics are used in microelectronics as active gate materials, in capacitors, electro-optical-acoustic modulators, etc. There is a particular demand for plastic ferroelectrics, e.g. as a sensor for acoustic imaging in medicine and beyond, in shapeable capacitors, etc. Microscopic mechanisms of ferroelectric polarization in traditional materials are typically ionic. In this talk we discuss the electronic ferroelectrics - carbon-based materials: organic crystals, conducting polymers and graphene nano-ribbons. The motion of walls, separating domains with opposite electric polarisation, can be influenced and manipulated by terahertz and infra-red range optics.

Manipulation based on sensor-directed control: An integrated end effector and touch sensing system

NASA Technical Reports Server (NTRS)

Hill, J. W.; Sword, A. J.

1973-01-01

A hand/touch sensing system is described that, when mounted on a position-controlled manipulator, greatly expands the kinds of automated manipulation tasks that can be undertaken. Because of the variety of coordinate conversions, control equations, and completion criteria, control is necessarily dependent upon a small digital computer. The sensing system is designed both to be rugged and to sense the necessary touch and force information required to execute a wide range of manipulation tasks. The system consists of a six-axis wrist sensor, external touch sensors, and a pair of matrix jaw sensors. Details of the construction of the particular sensors, the integration of the end effector into the sensor system, and the control algorithms for using the sensor outputs to perform manipulation tasks automatically are discussed.

Development of A Low-Cost FPGA-Based Measurement System for Real-Time Processing of Acoustic Emission Data: Proof of Concept Using Control of Pulsed Laser Ablation in Liquids.

PubMed

Wirtz, Sebastian F; Cunha, Adauto P A; Labusch, Marc; Marzun, Galina; Barcikowski, Stephan; Söffker, Dirk

2018-06-01

Today, the demand for continuous monitoring of valuable or safety critical equipment is increasing in many industrial applications due to safety and economical requirements. Therefore, reliable in-situ measurement techniques are required for instance in Structural Health Monitoring (SHM) as well as process monitoring and control. Here, current challenges are related to the processing of sensor data with a high data rate and low latency. In particular, measurement and analyses of Acoustic Emission (AE) are widely used for passive, in-situ inspection. Advantages of AE are related to its sensitivity to different micro-mechanical mechanisms on the material level. However, online processing of AE waveforms is computationally demanding. The related equipment is typically bulky, expensive, and not well suited for permanent installation. The contribution of this paper is the development of a Field Programmable Gate Array (FPGA)-based measurement system using ZedBoard devlopment kit with Zynq-7000 system on chip for embedded implementation of suitable online processing algorithms. This platform comprises a dual-core Advanced Reduced Instruction Set Computer Machine (ARM) architecture running a Linux operating system and FPGA fabric. A FPGA-based hardware implementation of the discrete wavelet transform is realized to accelerate processing the AE measurements. Key features of the system are low cost, small form factor, and low energy consumption, which makes it suitable to serve as field-deployed measurement and control device. For verification of the functionality, a novel automatically realized adjustment of the working distance during pulsed laser ablation in liquids is established as an example. A sample rate of 5 MHz is achieved at 16 bit resolution.

Development of a nanowire based titanium needle probe sensor for glucose monitoring

NASA Astrophysics Data System (ADS)

Deshpande, Devesh C.

The need for continuous monitoring of various physiological functions such as blood glucose levels, neural functions and cholesterol levels has fostered the research and development of various schemes of biosensors to sense and help control the respective function. The needs of patients for sensors with minimal discomfort, longer life and better performance have necessitated the development towards smaller and more efficient sensors. In addition, the need for higher functionality from smaller sensors has led to the development of sensors with multiple electrodes, each electrode capable of sensing a different body function. Such multi-electrode sensors need to be fabricated using micro-fabrication processes in order to achieve precise control over the size, shape and placement of the electrodes. Multielectrode sensors fabricated using silicon and polymers have been demonstrated. One physiological function that attracts widespread interest is continuous glucose monitoring in our blood, since Diabetes affects millions of people all over the world. Significant deviations of blood glucose levels from the normal levels of 4-8 mM can cause fainting, coma and damage to the eyes, kidneys, nerves and blood vessels. For chronic patients, continuous monitoring of glucose levels is essential for accurate and timely treatment. A few continuous monitoring sensors are available in the market, but they have problems and cannot replace the strip type one-time glucose monitoring systems as yet. To address this need, large scale research efforts have been targeted towards continuous monitoring. The demand for higher accuracy and sensitivity has motivated researchers to evaluate the use of nanostructures in sensing. The large surface area-to-volume ratio of such structures could enable further miniaturization and push the detection limits, potentially enabling even single molecule detection. This research involved the development of a biocompatible titanium needle probe sensor for glucose monitoring. The working electrode of the sensor comprised of vertically aligned, free standing Au nanowires to utilize the advantages of nanostructures. The sensor was fabricated on biocompatible titanium substrate using Micro/Nano fabrication processes such as Plasma Enhanced Chemical Vapor Deposition (PECVD), Electron Beam Evaporation, Lithography, aligned nanowire growth and wet and plasma etching. Arrays of free-standing nanowires were grown at room temperature and pressure using a novel template based growth process. After fabrication of the sensor, immobilization of an enzyme was carried out on the sensing electrode to ensure selectivity of the sensor to glucose. This was achieved by using self-assembled thiol monolayers and entrapment in a conducting polymer matrix. Glucose oxidase was used for this purpose, which catalyzed the conversion of glucose to gluconic acid, producing hydrogen peroxide in the process. Amperometry was used for glucose detection, in which a constant voltage was applied to the sensor. This potential oxidized the hydrogen peroxide and produced changes in the current which were correlated to the glucose concentration. This dissertation will address the importance of continuous glucose monitoring, current technology and problems faced, the design and fabrication of the sensor and electrochemical sensing to detect glucose levels in solution. Finally, the problems encountered during the process will be discussed and the future work will be detailed.

Multi-Domain SDN Survivability for Agricultural Wireless Sensor Networks.

PubMed

Huang, Tao; Yan, Siyu; Yang, Fan; Liu, Jiang

2016-11-06

Wireless sensor networks (WSNs) have been widely applied in agriculture field; meanwhile, the advent of multi-domain software-defined networks (SDNs) have improved the wireless resource utilization rate and strengthened network management. In recent times, multi-domain SDNs have been applied to agricultural sensor networks, namely multi-domain software-defined wireless sensor networks (SDWSNs). However, when the SDNs controlling agriculture networks suddenly become unavailable, whether intra-domain or inter-domain, sensor network communication is abnormal because of the loss of control. Moreover, there are controller and switch info-updating problems even if the controller becomes available again. To resolve these problems, this paper proposes a new approach based on an Open vSwitch extension for multi-domain SDWSNs, which can enhance agriculture network survivability and stability. We achieved this by designing a connection-state mechanism, a communication mechanism on both L2 and L3, and an info-updating mechanism based on Open vSwitch. The experimental results show that, whether it is agricultural inter-domain or intra-domain during the controller failure period, the sensor switches can enter failure recovery mode as soon as possible so that the sensor network keeps a stable throughput, a short failure recovery time below 300 ms, and low packet loss. Further, the domain can smoothly control the domain network again once the controller becomes available. This approach based on an Open vSwitch extension can enhance the survivability and stability of multi-domain SDWSNs in precision agriculture.

Multi-Domain SDN Survivability for Agricultural Wireless Sensor Networks

PubMed Central

Huang, Tao; Yan, Siyu; Yang, Fan; Liu, Jiang

2016-01-01

Wireless sensor networks (WSNs) have been widely applied in agriculture field; meanwhile, the advent of multi-domain software-defined networks (SDNs) have improved the wireless resource utilization rate and strengthened network management. In recent times, multi-domain SDNs have been applied to agricultural sensor networks, namely multi-domain software-defined wireless sensor networks (SDWSNs). However, when the SDNs controlling agriculture networks suddenly become unavailable, whether intra-domain or inter-domain, sensor network communication is abnormal because of the loss of control. Moreover, there are controller and switch info-updating problems even if the controller becomes available again. To resolve these problems, this paper proposes a new approach based on an Open vSwitch extension for multi-domain SDWSNs, which can enhance agriculture network survivability and stability. We achieved this by designing a connection-state mechanism, a communication mechanism on both L2 and L3, and an info-updating mechanism based on Open vSwitch. The experimental results show that, whether it is agricultural inter-domain or intra-domain during the controller failure period, the sensor switches can enter failure recovery mode as soon as possible so that the sensor network keeps a stable throughput, a short failure recovery time below 300 ms, and low packet loss. Further, the domain can smoothly control the domain network again once the controller becomes available. This approach based on an Open vSwitch extension can enhance the survivability and stability of multi-domain SDWSNs in precision agriculture. PMID:27827971

Evaluation of Smartphone Inertial Sensor Performance for Cross-Platform Mobile Applications

PubMed Central

Kos, Anton; Tomažič, Sašo; Umek, Anton

2016-01-01

Smartphone sensors are being increasingly used in mobile applications. The performance of sensors varies considerably among different smartphone models and the development of a cross-platform mobile application might be a very complex and demanding task. A publicly accessible resource containing real-life-situation smartphone sensor parameters could be of great help for cross-platform developers. To address this issue we have designed and implemented a pilot participatory sensing application for measuring, gathering, and analyzing smartphone sensor parameters. We start with smartphone accelerometer and gyroscope bias and noise parameters. The application database presently includes sensor parameters of more than 60 different smartphone models of different platforms. It is a modest, but important start, offering information on several statistical parameters of the measured smartphone sensors and insights into their performance. The next step, a large-scale cloud-based version of the application, is already planned. The large database of smartphone sensor parameters may prove particularly useful for cross-platform developers. It may also be interesting for individual participants who would be able to check-up and compare their smartphone sensors against a large number of similar or identical models. PMID:27049391

Climate change and peak demand for electricity: Evaluating policies for reducing peak demand under different climate change scenarios

NASA Astrophysics Data System (ADS)

Anthony, Abigail Walker

This research focuses on the relative advantages and disadvantages of using price-based and quantity-based controls for electricity markets. It also presents a detailed analysis of one specific approach to quantity based controls: the SmartAC program implemented in Stockton, California. Finally, the research forecasts electricity demand under various climate scenarios, and estimates potential cost savings that could result from a direct quantity control program over the next 50 years in each scenario. The traditional approach to dealing with the problem of peak demand for electricity is to invest in a large stock of excess capital that is rarely used, thereby greatly increasing production costs. Because this approach has proved so expensive, there has been a focus on identifying alternative approaches for dealing with peak demand problems. This research focuses on two approaches: price based approaches, such as real time pricing, and quantity based approaches, whereby the utility directly controls at least some elements of electricity used by consumers. This research suggests that well-designed policies for reducing peak demand might include both price and quantity controls. In theory, sufficiently high peak prices occurring during periods of peak demand and/or low supply can cause the quantity of electricity demanded to decline until demand is in balance with system capacity, potentially reducing the total amount of generation capacity needed to meet demand and helping meet electricity demand at the lowest cost. However, consumers need to be well informed about real-time prices for the pricing strategy to work as well as theory suggests. While this might be an appropriate assumption for large industrial and commercial users who have potentially large economic incentives, there is not yet enough research on whether households will fully understand and respond to real-time prices. Thus, while real-time pricing can be an effective tool for addressing the peak load problems, pricing approaches are not well suited to ensure system reliability. This research shows that direct quantity controls are better suited for avoiding catastrophic failure that results when demand exceeds supply capacity.

Flexible, Cuttable, and Self-Waterproof Bending Strain Sensors Using Microcracked Gold Nanofilms@Paper Substrate.

PubMed

Liao, Xinqin; Zhang, Zheng; Liang, Qijie; Liao, Qingliang; Zhang, Yue

2017-02-01

Rapid advances in functional sensing electronics place tremendous demands on innovation toward creative uses of versatile advanced materials and effective designs of device structures. Here, we first report a feasible and effective fabrication strategy to integrate commercial abrasive papers with microcracked gold (Au) nanofilms to construct cuttable and self-waterproof crack-based resistive bending strain sensors. Via introducing surface microstructures, the sensitivities of the bending strain sensors are greatly enhanced by 27 times than that of the sensors without surface microstructures, putting forward an alternative suggestion for other flexible electronics to improve their performances. Besides, the bending strain sensors also endow rapid response and relaxation time of 20 ms and ultrahigh stability of >18 000 strain loading-unloading cycles in conjunction with flexibility and robustness. In addition, the concepts of cuttability and self-waterproofness (attain and even surpass IPX-7) of the bending strain sensors have been demonstrated. Because of the distinctive sensing properties, flexibility, cuttability, and self-waterproofness, the bending strain sensors are attractive and promising for wearable electronic devices and smart health monitoring system.

Highly Efficient Gas Sensor Using a Hollow SnO2 Microfiber for Triethylamine Detection.

PubMed

Zou, Yihui; Chen, Shuai; Sun, Jin; Liu, Jingquan; Che, Yanke; Liu, Xianghong; Zhang, Jun; Yang, Dongjiang

2017-07-28

Triethylamine (TEA) gas sensors having excellent response and selectivity are in great demand to monitor the real environment. In this work, we have successfully prepared a hollow SnO 2 microfiber by a unique sustainable biomass conversion strategy and shown that the microfiber can be used in a high-performance gas sensor. The sensor based on the hollow SnO 2 microfiber shows a quick response/recovery toward triethylamine. The response of the hollow SnO 2 microfiber is up to 49.5 when the concentration of TEA gas is 100 ppm. The limit of detection is as low as 2 ppm. Furthermore, the sensor has a relatively low optimal operation temperature of 270 °C, which is lower than those of many other reported sensors. The excellent sensing properties are largely attributed to the high sensitivity provided by SnO 2 and the good permeability and conductivity of the one-dimensional hollow structure. Thus, the hollow SnO 2 microfiber using sustainable biomass as a template is a significant strategy for a unique TEA gas sensor.

Open architecture CMM motion controller

NASA Astrophysics Data System (ADS)

Chang, David; Spence, Allan D.; Bigg, Steve; Heslip, Joe; Peterson, John

2001-12-01

Although initially the only Coordinate Measuring Machine (CMM) sensor available was a touch trigger probe, technological advances in sensors and computing have greatly increased the variety of available inspection sensors. Non-contact laser digitizers and analog scanning touch probes require very well tuned CMM motion control, as well as an extensible, open architecture interface. This paper describes the implementation of a retrofit CMM motion controller designed for open architecture interface to a variety of sensors. The controller is based on an Intel Pentium microcomputer and a Servo To Go motion interface electronics card. Motor amplifiers, safety, and additional interface electronics are housed in a separate enclosure. Host Signal Processing (HSP) is used for the motion control algorithm. Compared to the usual host plus DSP architecture, single CPU HSP simplifies integration with the various sensors, and implementation of software geometric error compensation. Motion control tuning is accomplished using a remote computer via 100BaseTX Ethernet. A Graphical User Interface (GUI) is used to enter geometric error compensation data, and to optimize the motion control tuning parameters. It is shown that this architecture achieves the required real time motion control response, yet is much easier to extend to additional sensors.

Study on robot motion control for intelligent welding processes based on the laser tracking sensor

NASA Astrophysics Data System (ADS)

Zhang, Bin; Wang, Qian; Tang, Chen; Wang, Ju

2017-06-01

A robot motion control method is presented for intelligent welding processes of complex spatial free-form curve seams based on the laser tracking sensor. First, calculate the tip position of the welding torch according to the velocity of the torch and the seam trajectory detected by the sensor. Then, search the optimal pose of the torch under constraints using genetic algorithms. As a result, the intersection point of the weld seam and the laser plane of the sensor is within the detectable range of the sensor. Meanwhile, the angle between the axis of the welding torch and the tangent of the weld seam meets the requirements. The feasibility of the control method is proved by simulation.

Characterizing Graphene-modified Electrodes for Interfacing with Arduino®-based Devices.

PubMed

Arris, Farrah Aida; Ithnin, Mohamad Hafiz; Salim, Wan Wardatul Amani Wan

2016-08-01

Portable low-cost platform and sensing systems for identification and quantitative measurement are in high demand for various environmental monitoring applications, especially in field work. Quantifying parameters in the field requires both minimal sample handling and a device capable of performing measurements with high sensitivity and stability. Furthermore, the one-device-fits-all concept is useful for continuous monitoring of multiple parameters. Miniaturization of devices can be achieved by introducing graphene as part of the transducer in an electrochemical sensor. In this project, we characterize graphene deposition methods on glassy-carbon electrodes (GCEs) with the goal of interfacing with an Arduino-based user-friendly microcontroller. We found that a galvanostatic electrochemical method yields the highest peak current of 10 mA, promising a highly sensitive electrochemical sensor. An Atlas Scientific™ printed circuit board (PCB) was connected to an Arduino® microcontroller using a multi-circuit connection that can be interfaced with graphene-based electrochemical sensors for environmental monitoring.

A Human-Centered Smart Home System with Wearable-Sensor Behavior Analysis

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

Ji, Jianting; Liu, Ting; Shen, Chao

Smart home has recently attracted much research interest owing to its potential in improving the quality of human life. How to obtain user's demand is the most important and challenging task for appliance optimal scheduling in smart home, since it is highly related to user's unpredictable behavior. In this paper, a human-centered smart home system is proposed to identify user behavior, predict their demand and schedule the household appliances. Firstly, the sensor data from user's wearable devices are monitored to profile user's full-day behavior. Then, the appliance-demand matrix is constructed to predict user's demand on home environment, which is extractedmore » from the history of appliance load data and user behavior. Two simulations are designed to demonstrate user behavior identification, appliance-demand matrix construction and strategy of appliance optimal scheduling generation.« less

Sap flow sensors: construction, quality control and comparison.

PubMed

Davis, Tyler W; Kuo, Chen-Min; Liang, Xu; Yu, Pao-Shan

2012-01-01

This work provides a design for two types of sensors, based on the thermal dissipation and heat ratio methods of sap flow calculation, for moderate to large scale deployments for the purpose of monitoring tree transpiration. These designs include a procedure for making these sensors, a quality control method for the final products, and a complete list of components with vendors and pricing information. Both sensor designs were field tested alongside a commercial sap flow sensor to assess their performance and show the importance for quality controlling the sensor outputs. Results show that for roughly 2% of the cost of commercial sensors, self-made sap flow sensors can provide acceptable estimates of the sap flow measurements compared to the commercial sensors.

Multi-mode sensor processing on a dynamically reconfigurable massively parallel processor array

NASA Astrophysics Data System (ADS)

Chen, Paul; Butts, Mike; Budlong, Brad; Wasson, Paul

2008-04-01

This paper introduces a novel computing architecture that can be reconfigured in real time to adapt on demand to multi-mode sensor platforms' dynamic computational and functional requirements. This 1 teraOPS reconfigurable Massively Parallel Processor Array (MPPA) has 336 32-bit processors. The programmable 32-bit communication fabric provides streamlined inter-processor connections with deterministically high performance. Software programmability, scalability, ease of use, and fast reconfiguration time (ranging from microseconds to milliseconds) are the most significant advantages over FPGAs and DSPs. This paper introduces the MPPA architecture, its programming model, and methods of reconfigurability. An MPPA platform for reconfigurable computing is based on a structural object programming model. Objects are software programs running concurrently on hundreds of 32-bit RISC processors and memories. They exchange data and control through a network of self-synchronizing channels. A common application design pattern on this platform, called a work farm, is a parallel set of worker objects, with one input and one output stream. Statically configured work farms with homogeneous and heterogeneous sets of workers have been used in video compression and decompression, network processing, and graphics applications.

NASA Tech Briefs, January 2010

NASA Technical Reports Server (NTRS)

2010-01-01

Topics covered include: Cryogenic Flow Sensor; Multi-Sensor Mud Detection; Gas Flow Detection System; Mapping Capacitive Coupling Among Pixels in a Sensor Array; Fiber-Based Laser Transmitter for Oxygen A-Band Spectroscopy and Remote Sensing; Low-Profile, Dual-Wavelength, Dual-Polarized Antenna; Time-Separating Heating and Sensor Functions of Thermistors in Precision Thermal Control Applications; Cellular Reflectarray Antenna; A One-Dimensional Synthetic-Aperture Microwave Radiometer; Electrical Switching of Perovskite Thin-Film Resistors; Two-Dimensional Synthetic-Aperture Radiometer; Ethernet-Enabled Power and Communication Module for Embedded Processors; Electrically Variable Resistive Memory Devices; Improved Attachment in a Hybrid Inflatable Pressure Vessel; Electrostatic Separator for Beneficiation of Lunar Soil; Amorphous Rover; Space-Frame Antenna; Gear-Driven Turnbuckle Actuator; In-Situ Focusing Inside a Thermal Vacuum Chamber; Space-Frame Lunar Lander; Wider-Opening Dewar Flasks for Cryogenic Storage; Silicon Oxycarbide Aerogels for High-Temperature Thermal Insulation; Supercapacitor Electrolyte Solvents with Liquid Range Below -80 C; Designs and Materials for Better Coronagraph Occulting Masks; Fuel-Cell-Powered Vehicle with Hybrid Power Management; Fine-Water-Mist Multiple-Orientation-Discharge Fire Extinguisher; Fuel-Cell Water Separator; Turbulence and the Stabilization Principle; Improved Cloud Condensation Nucleus Spectrometer; Better Modeling of Electrostatic Discharge in an Insulator; Sub-Aperture Interferometers; Terahertz Mapping of Microstructure and Thickness Variations; Multiparallel Three-Dimensional Optical Microscopy; Stabilization of Phase of a Sinusoidal Signal Transmitted Over Optical Fiber; Vacuum-Compatible Wideband White Light and Laser Combiner Source System; Optical Tapers as White-Light WGM Resonators; EPR Imaging at a Few Megahertz Using SQUID Detectors; Reducing Field Distortion in Magnetic Resonance Imaging; Fluorogenic Cell-Based Biosensors for Monitoring Microbes; A Constant-Force Resistive Exercise Unit; GUI to Facilitate Research on Biological Damage from Radiation; On-Demand Urine Analyzer; More-Realistic Digital Modeling of a Human Body; and Advanced Liquid-Cooling Garment Using Highly Thermally Conductive Sheets.

The research of single intersection sensor signal control based on section data

NASA Astrophysics Data System (ADS)

Liu, Yunxiang; Huang, Yue; Wang, Hao

2016-12-01

Propose a sensing signal intersection control design electronic license based on the design by setting the intersection readers to interact with active electronic tags equipped vehicles, vehicle information obtained on the road section. In the vehicle detection sensor may control the green density as evaluation criteria are extended when the vehicle is higher than the threshold, the green density continuity, whereas the switching phases. Induction showed improved control strategy can achieve real-time traffic signal control effectively in high saturation intersection, to overcome the traditional sensor control failure at high saturation drawbacks and improve the utilization of urban Intersection comparative analysis by simulation.

Arrays of Nano Tunnel Junctions as Infrared Image Sensors

NASA Technical Reports Server (NTRS)

Son, Kyung-Ah; Moon, Jeong S.; Prokopuk, Nicholas

2006-01-01

Infrared image sensors based on high density rectangular planar arrays of nano tunnel junctions have been proposed. These sensors would differ fundamentally from prior infrared sensors based, variously, on bolometry or conventional semiconductor photodetection. Infrared image sensors based on conventional semiconductor photodetection must typically be cooled to cryogenic temperatures to reduce noise to acceptably low levels. Some bolometer-type infrared sensors can be operated at room temperature, but they exhibit low detectivities and long response times, which limit their utility. The proposed infrared image sensors could be operated at room temperature without incurring excessive noise, and would exhibit high detectivities and short response times. Other advantages would include low power demand, high resolution, and tailorability of spectral response. Neither bolometers nor conventional semiconductor photodetectors, the basic detector units as proposed would partly resemble rectennas. Nanometer-scale tunnel junctions would be created by crossing of nanowires with quantum-mechanical-barrier layers in the form of thin layers of electrically insulating material between them (see figure). A microscopic dipole antenna sized and shaped to respond maximally in the infrared wavelength range that one seeks to detect would be formed integrally with the nanowires at each junction. An incident signal in that wavelength range would become coupled into the antenna and, through the antenna, to the junction. At the junction, the flow of electrons between the crossing wires would be dominated by quantum-mechanical tunneling rather than thermionic emission. Relative to thermionic emission, quantum mechanical tunneling is a fast process.

Direct detection of cysteine using functionalized BaTiO3 nanoparticles film based self-powered biosensor.

PubMed

Selvarajan, Sophia; Alluri, Nagamalleswara Rao; Chandrasekhar, Arunkumar; Kim, Sang-Jae

2017-05-15

Simple, novel, and direct detection of clinically important biomolecules have continuous demand among scientific community as well as in market. Here, we report the first direct detection and facile fabrication of a cysteine-responsive, film-based, self-powered device. NH 2 functionalized BaTiO 3 nanoparticles (BT-NH 2 NPs) suspended in a three-dimensional matrix of an agarose (Ag) film, were used for cysteine detection. BaTiO 3 nanoparticles (BT NPs) semiconducting as well as piezoelectric properties were harnessed in this study. The changes in surface charge properties of the film with respect to cysteine concentrations were determined using a current-voltage (I-V) technique. The current response increased with cysteine concentration (linear concentration range=10µM-1mM). Based on the properties of the composite (BT/Ag), we created a self-powered cysteine sensor in which the output voltage from a piezoelectric nanogenerator was used to drive the sensor. The potential drop across the sensor was measured as a function of cysteine concentrations. Real-time analysis of sensor performance was carried out on urine samples by non-invasive method. This novel sensor demonstrated good selectivity, linear concentration range and detection limit of 10µM; acceptable for routine analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

High Reliability Engine Control Demonstrated for Aircraft Engines

NASA Technical Reports Server (NTRS)

Guo, Ten-Huei

1999-01-01

For a dual redundant-control system, which is typical for short-haul aircraft, if a failure is detected in a control sensor, the engine control is transferred to a safety mode and an advisory is issued for immediate maintenance action to replace the failed sensor. The safety mode typically results in severely degraded engine performance. The goal of the High Reliability Engine Control (HREC) program was to demonstrate that the neural-network-based sensor validation technology can safely operate an engine by using the nominal closed-loop control during and after sensor failures. With this technology, engine performance could be maintained, and the sensor could be replaced as a conveniently scheduled maintenance action.

In-line quality control of moving objects by means of spectral-domain OCT

NASA Astrophysics Data System (ADS)

Markl, Daniel; Hannesschläger, Günther; Buchsbaum, Andreas; Sacher, Stephan; Khinast, Johannes G.; Leitner, Michael

2014-08-01

In-line quality control of intermediate and final products is essential in various industries. This may imply determining the thickness of a foil or evaluating the homogeneity of coating applied to a pharmaceutical tablet. Such a qualitative and quantitative monitoring in a depth-resolved manner can be accomplished using optical coherence tomography (OCT). In-line quality control based on OCT requires additional consideration of motion effects for the system design as well as for data interpretation. This study focuses on transverse motion effects that can arise in spectral-domain (SD-) OCT systems. The impact of a transverse movement is analyzed for a constant relative speed difference up to 0.7 m/s between sample and sensor head. In particular, transverse motion is affecting OCT system properties such as the beam displacement (distance between adjacent A-scans) and transverse resolution. These properties were evaluated theoretically and experimentally for OCT images of a resolution target and pharmaceutical film-coated tablets. Both theoretical and experimental analyses highlight the shift of the transverse resolution limiting factor from the optics to the beam displacement above a relative speed difference between sensor head and sample of 0.42 m/s (for the presented SD-OCT setup). Speeds above 0.4 m/s are often demanded when monitoring industrial processes, such as a coating process when producing film-coated tablets. This emphasizes the importance of a fast data acquisition when using OCT as in-line quality control tool.

Integrated control-system design via generalized LQG (GLQG) theory

NASA Technical Reports Server (NTRS)

Bernstein, Dennis S.; Hyland, David C.; Richter, Stephen; Haddad, Wassim M.

1989-01-01

Thirty years of control systems research has produced an enormous body of theoretical results in feedback synthesis. Yet such results see relatively little practical application, and there remains an unsettling gap between classical single-loop techniques (Nyquist, Bode, root locus, pole placement) and modern multivariable approaches (LQG and H infinity theory). Large scale, complex systems, such as high performance aircraft and flexible space structures, now demand efficient, reliable design of multivariable feedback controllers which optimally tradeoff performance against modeling accuracy, bandwidth, sensor noise, actuator power, and control law complexity. A methodology is described which encompasses numerous practical design constraints within a single unified formulation. The approach, which is based upon coupled systems or modified Riccati and Lyapunov equations, encompasses time-domain linear-quadratic-Gaussian theory and frequency-domain H theory, as well as classical objectives such as gain and phase margin via the Nyquist circle criterion. In addition, this approach encompasses the optimal projection approach to reduced-order controller design. The current status of the overall theory will be reviewed including both continuous-time and discrete-time (sampled-data) formulations.

A Novel Energy Efficient Topology Control Scheme Based on a Coverage-Preserving and Sleep Scheduling Model for Sensor Networks

PubMed Central

Shi, Binbin; Wei, Wei; Wang, Yihuai; Shu, Wanneng

2016-01-01

In high-density sensor networks, scheduling some sensor nodes to be in the sleep mode while other sensor nodes remain active for monitoring or forwarding packets is an effective control scheme to conserve energy. In this paper, a Coverage-Preserving Control Scheduling Scheme (CPCSS) based on a cloud model and redundancy degree in sensor networks is proposed. Firstly, the normal cloud model is adopted for calculating the similarity degree between the sensor nodes in terms of their historical data, and then all nodes in each grid of the target area can be classified into several categories. Secondly, the redundancy degree of a node is calculated according to its sensing area being covered by the neighboring sensors. Finally, a centralized approximation algorithm based on the partition of the target area is designed to obtain the approximate minimum set of nodes, which can retain the sufficient coverage of the target region and ensure the connectivity of the network at the same time. The simulation results show that the proposed CPCSS can balance the energy consumption and optimize the coverage performance of the sensor network. PMID:27754405

A Novel Energy Efficient Topology Control Scheme Based on a Coverage-Preserving and Sleep Scheduling Model for Sensor Networks.

PubMed

Shi, Binbin; Wei, Wei; Wang, Yihuai; Shu, Wanneng

2016-10-14

In high-density sensor networks, scheduling some sensor nodes to be in the sleep mode while other sensor nodes remain active for monitoring or forwarding packets is an effective control scheme to conserve energy. In this paper, a Coverage-Preserving Control Scheduling Scheme (CPCSS) based on a cloud model and redundancy degree in sensor networks is proposed. Firstly, the normal cloud model is adopted for calculating the similarity degree between the sensor nodes in terms of their historical data, and then all nodes in each grid of the target area can be classified into several categories. Secondly, the redundancy degree of a node is calculated according to its sensing area being covered by the neighboring sensors. Finally, a centralized approximation algorithm based on the partition of the target area is designed to obtain the approximate minimum set of nodes, which can retain the sufficient coverage of the target region and ensure the connectivity of the network at the same time. The simulation results show that the proposed CPCSS can balance the energy consumption and optimize the coverage performance of the sensor network.

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.

Connected Dominating Set Based Topology Control in Wireless Sensor Networks

ERIC Educational Resources Information Center

He, Jing

2012-01-01

Wireless Sensor Networks (WSNs) are now widely used for monitoring and controlling of systems where human intervention is not desirable or possible. Connected Dominating Sets (CDSs) based topology control in WSNs is one kind of hierarchical method to ensure sufficient coverage while reducing redundant connections in a relatively crowded network.…

An observer-based compensator for distributed delays

NASA Technical Reports Server (NTRS)

Luck, Rogelio; Ray, Asok

1990-01-01

This paper presents an algorithm for compensating delays that are distributed between the sensor(s), controller and actuator(s) within a control loop. This observer-based algorithm is specially suited to compensation of network-induced delays in integrated communication and control systems. The robustness of the algorithm relative to plant model uncertainties has been examined.

Optimal Power Control in Wireless Powered Sensor Networks: A Dynamic Game-Based Approach

PubMed Central

Xu, Haitao; Guo, Chao; Zhang, Long

2017-01-01

In wireless powered sensor networks (WPSN), it is essential to research uplink transmit power control in order to achieve throughput performance balancing and energy scheduling. Each sensor should have an optimal transmit power level for revenue maximization. In this paper, we discuss a dynamic game-based algorithm for optimal power control in WPSN. The main idea is to use the non-cooperative differential game to control the uplink transmit power of wireless sensors in WPSN, to extend their working hours and to meet QoS (Quality of Services) requirements. Subsequently, the Nash equilibrium solutions are obtained through Bellman dynamic programming. At the same time, an uplink power control algorithm is proposed in a distributed manner. Through numerical simulations, we demonstrate that our algorithm can obtain optimal power control and reach convergence for an infinite horizon. PMID:28282945

Long-term monitoring FBG-based cable load sensor

NASA Astrophysics Data System (ADS)

Zhang, Zhichun; Zhou, Zhi; Wang, Chuan; Ou, Jinping

2006-03-01

Stay cables are the main load-bearing components of stayed-cable bridges. The cables stress status is an important factor to the stayed-cable bridge structure safety evaluation. So it's very important not only to the bridge construction, but also to the long-term safety evaluation for the bridge structure in-service. The accurate measurement for cable load depends on an effective sensor, especially to meet the long time durability and measurement demand. FBG, for its great advantage of corrosion resistance, absolute measurement, high accuracy, electro-magnetic resistance, quasi-distribution sensing, absolute measurement and so on, is the most promising sensor, which can cater for the cable force monitoring. In this paper, a load sensor has been developed, which is made up of a bushing elastic supporting body, 4 FBGs uniformly-spaced attached outside of the bushing supporting body, and a temperature compensation FBG for other four FBGs, moreover a cover for protection of FBGs. Firstly, the sensor measuring principle is analyzed, and relationship equation of FBG wavelength shifts and extrinsic load has also been gotten. And then the sensor calibration experiments of a steel cable stretching test with the FBG load sensor and a reference electric pressure sensor is finished, and the results shows excellent linearity of extrinsic load and FBG wavelength shifts, and good repeatability, which indicates that such kind of FBG-based load sensor is suitable for load measurement, especially for long-term, real time monitoring of stay-cables.

A fiber optic temperature sensor based on multi-core microstructured fiber with coupled cores for a high temperature environment

NASA Astrophysics Data System (ADS)

Makowska, A.; Markiewicz, K.; Szostkiewicz, L.; Kolakowska, A.; Fidelus, J.; Stanczyk, T.; Wysokinski, K.; Budnicki, D.; Ostrowski, L.; Szymanski, M.; Makara, M.; Poturaj, K.; Tenderenda, T.; Mergo, P.; Nasilowski, T.

2018-02-01

Sensors based on fiber optics are irreplaceable wherever immunity to strong electro-magnetic fields or safe operation in explosive atmospheres is needed. Furthermore, it is often essential to be able to monitor high temperatures of over 500°C in such environments (e.g. in cooling systems or equipment monitoring in power plants). In order to meet this demand, we have designed and manufactured a fiber optic sensor with which temperatures up to 900°C can be measured. The sensor utilizes multi-core fibers which are recognized as the dedicated medium for telecommunication or shape sensing, but as we show may be also deployed advantageously in new types of fiber optic temperature sensors. The sensor presented in this paper is based on a dual-core microstructured fiber Michelson interferometer. The fiber is characterized by strongly coupled cores, hence it acts as an all-fiber coupler, but with an outer diameter significantly wider than a standard fused biconical taper coupler, which significantly increases the coupling region's mechanical reliability. Owing to the proposed interferometer imbalance, effective operation and high-sensitivity can be achieved. The presented sensor is designed to be used at high temperatures as a result of the developed low temperature chemical process of metal (copper or gold) coating. The hermetic metal coating can be applied directly to the silica cladding of the fiber or the fiber component. This operation significantly reduces the degradation of sensors due to hydrolysis in uncontrolled atmospheres and high temperatures.

Conductive fiber-based ultrasensitive textile pressure sensor for wearable electronics.

PubMed

Lee, Jaehong; Kwon, Hyukho; Seo, Jungmok; Shin, Sera; Koo, Ja Hoon; Pang, Changhyun; Son, Seungbae; Kim, Jae Hyung; Jang, Yong Hoon; Kim, Dae Eun; Lee, Taeyoon

2015-04-17

A flexible and sensitive textile-based pressure sensor is developed using highly conductive fibers coated with dielectric rubber materials. The pressure sensor exhibits superior sensitivity, very fast response time, and high stability, compared with previous textile-based pressure sensors. By using a weaving method, the pressure sensor can be applied to make smart gloves and clothes that can control machines wirelessly as human-machine interfaces. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

HETDEX tracker control system design and implementation

NASA Astrophysics Data System (ADS)

Beno, Joseph H.; Hayes, Richard; Leck, Ron; Penney, Charles; Soukup, Ian

2012-09-01

To enable the Hobby-Eberly Telescope Dark Energy Experiment, The University of Texas at Austin Center for Electromechanics and McDonald Observatory developed a precision tracker and control system - an 18,000 kg robot to position a 3,100 kg payload within 10 microns of a desired dynamic track. Performance requirements to meet science needs and safety requirements that emerged from detailed Failure Modes and Effects Analysis resulted in a system of 13 precision controlled actuators and 100 additional analog and digital devices (primarily sensors and safety limit switches). Due to this complexity, demanding accuracy requirements, and stringent safety requirements, two independent control systems were developed. First, a versatile and easily configurable centralized control system that links with modeling and simulation tools during the hardware and software design process was deemed essential for normal operation including motion control. A second, parallel, control system, the Hardware Fault Controller (HFC) provides independent monitoring and fault control through a dedicated microcontroller to force a safe, controlled shutdown of the entire system in the event a fault is detected. Motion controls were developed in a Matlab-Simulink simulation environment, and coupled with dSPACE controller hardware. The dSPACE real-time operating system collects sensor information; motor commands are transmitted over a PROFIBUS network to servo amplifiers and drive motor status is received over the same network. To interface the dSPACE controller directly to absolute Heidenhain sensors with EnDat 2.2 protocol, a custom communication board was developed. This paper covers details of operational control software, the HFC, algorithms, tuning, debugging, testing, and lessons learned.

Method and System for Controlling a Dexterous Robot Execution Sequence Using State Classification

NASA Technical Reports Server (NTRS)

Sanders, Adam M. (Inventor); Quillin, Nathaniel (Inventor); Platt, Robert J., Jr. (Inventor); Pfeiffer, Joseph (Inventor); Permenter, Frank Noble (Inventor)

2014-01-01

A robotic system includes a dexterous robot and a controller. The robot includes a plurality of robotic joints, actuators for moving the joints, and sensors for measuring a characteristic of the joints, and for transmitting the characteristics as sensor signals. The controller receives the sensor signals, and is configured for executing instructions from memory, classifying the sensor signals into distinct classes via the state classification module, monitoring a system state of the robot using the classes, and controlling the robot in the execution of alternative work tasks based on the system state. A method for controlling the robot in the above system includes receiving the signals via the controller, classifying the signals using the state classification module, monitoring the present system state of the robot using the classes, and controlling the robot in the execution of alternative work tasks based on the present system state.

Self-organizing sensing and actuation for automatic control

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

Cheng, George Shu-Xing

A Self-Organizing Process Control Architecture is introduced with a Sensing Layer, Control Layer, Actuation Layer, Process Layer, as well as Self-Organizing Sensors (SOS) and Self-Organizing Actuators (SOA). A Self-Organizing Sensor for a process variable with one or multiple input variables is disclosed. An artificial neural network (ANN) based dynamic modeling mechanism as part of the Self-Organizing Sensor is described. As a case example, a Self-Organizing Soft-Sensor for CFB Boiler Bed Height is presented. Also provided is a method to develop a Self-Organizing Sensor.

Technologies for Fire and Damage Control and Condition Based Maintenance

DTIC Science & Technology

2011-12-01

sheathing, thermal and acoustic insulation, furnishing, bedding, mattresses, flooring , and wood fibre (paper and cardboard) and plastic packaging...Condition Based Maintenance”. The project objective was to develop an improved understanding of how materials, sensors and sensor systems choices impact the...ultraviolet spectral sensors and an acoustic sensor. The system also has data fusion software that analyses the sensor input and determines if the input

A Method of Data Aggregation for Wearable Sensor Systems

PubMed Central

Shen, Bo; Fu, Jun-Song

2016-01-01

Data aggregation has been considered as an effective way to decrease the data to be transferred in sensor networks. Particularly for wearable sensor systems, smaller battery has less energy, which makes energy conservation in data transmission more important. Nevertheless, wearable sensor systems usually have features like frequently dynamic changes of topologies and data over a large range, of which current aggregating methods can’t adapt to the demand. In this paper, we study the system composed of many wearable devices with sensors, such as the network of a tactical unit, and introduce an energy consumption-balanced method of data aggregation, named LDA-RT. In the proposed method, we develop a query algorithm based on the idea of ‘happened-before’ to construct a dynamic and energy-balancing routing tree. We also present a distributed data aggregating and sorting algorithm to execute top-k query and decrease the data that must be transferred among wearable devices. Combining these algorithms, LDA-RT tries to balance the energy consumptions for prolonging the lifetime of wearable sensor systems. Results of evaluation indicate that LDA-RT performs well in constructing routing trees and energy balances. It also outperforms the filter-based top-k monitoring approach in energy consumption, load balance, and the network’s lifetime, especially for highly dynamic data sources. PMID:27347953

A Flexible and Highly Sensitive Pressure Sensor Based on a PDMS Foam Coated with Graphene Nanoplatelets

PubMed Central

Rinaldi, Andrea; Tamburrano, Alessio; Fortunato, Marco; Sarto, Maria Sabrina

2016-01-01

The demand for high performance multifunctional wearable devices is more and more pushing towards the development of novel low-cost, soft and flexible sensors with high sensitivity. In the present work, we describe the fabrication process and the properties of new polydimethylsiloxane (PDMS) foams loaded with multilayer graphene nanoplatelets (MLGs) for application as high sensitive piezoresistive pressure sensors. The effective DC conductivity of the produced foams is measured as a function of MLG loading. The piezoresistive response of the MLG-PDMS foam-based sensor at different strain rates is assessed through quasi-static pressure tests. The results of the experimental investigations demonstrated that sensor loaded with 0.96 wt.% of MLGs is characterized by a highly repeatable pressure-dependent conductance after a few stabilization cycles and it is suitable for detecting compressive stresses as low as 10 kPa, with a sensitivity of 0.23 kPa−1, corresponding to an applied pressure of 70 kPa. Moreover, it is estimated that the sensor is able to detect pressure variations of ~1 Pa. Therefore, the new graphene-PDMS composite foam is a lightweight cost-effective material, suitable for sensing applications in the subtle or low and medium pressure ranges. PMID:27999251

Flexible Wing Base Micro Aerial Vehicles: Micro Air Vehicles (MAVs) for Surveillance and Remote Sensor Delivery

NASA Technical Reports Server (NTRS)

Ifju, Peter

2002-01-01

Micro Air Vehicles (MAVs) will be developed for tracking individuals, locating terrorist threats, and delivering remote sensors, for surveillance and chemical/biological agent detection. The tasks are: (1) Develop robust MAV platform capable of carrying sensor payload. (2) Develop fully autonomous capabilities for delivery of sensors to remote and distant locations. The current capabilities and accomplishments are: (1) Operational electric (inaudible) 6-inch MAVs with novel flexible wing, providing superior aerodynamic efficiency and control. (2) Vision-based flight stability and control (from on-board cameras).

CHIMERA II - A real-time multiprocessing environment for sensor-based robot control

NASA Technical Reports Server (NTRS)

Stewart, David B.; Schmitz, Donald E.; Khosla, Pradeep K.

1989-01-01

A multiprocessing environment for a wide variety of sensor-based robot system, providing the flexibility, performance, and UNIX-compatible interface needed for fast development of real-time code is addressed. The requirements imposed on the design of a programming environment for sensor-based robotic control is outlined. The details of the current hardware configuration are presented, along with the details of the CHIMERA II software. Emphasis is placed on the kernel, low-level interboard communication, user interface, extended file system, user-definable and dynamically selectable real-time schedulers, remote process synchronization, and generalized interprocess communication. A possible implementation of a hierarchical control model, the NASA/NBS standard reference model for telerobot control system is demonstrated.

Testing new technologies for the LISA Gravitational Reference Senso

NASA Astrophysics Data System (ADS)

Conklin, John; Chilton, Andrew; Olatunde, Taiwo; Apple, Stephen; Ciani, Giacomo; Mueller, Guido

2015-01-01

LISA will directly observe low-frequency gravitational waves emitted by sources ranging from super-massive black hole mergers to compact galactic binaries. A laser interferometer will measure picometer changes in the distances between free falling test masses separated by millions of kilometers. A test mass and its associated sensing, actuation, charge control and caging subsystems are referred to as a gravitational reference sensor (GRS). The demanding acceleration noise requirement of < 3×10-15 m/sec2Hz1/2 for the LISA GRS has motivated a rigorous testing campaign in Europe and a dedicated technology mission, LISA Pathfinder, scheduled for launch in the summer of 2015. At the University of Florida we are developing a nearly thermally noise limited torsion pendulum for testing GRS technology enhancements and for understanding the dozens of acceleration noise sources that affect the performance of the GRS. This experimental facility is based on the design of a similar facility at the University of Trento, and consists of a vacuum enclosed torsion pendulum that suspends mock-ups of the LISA test masses, surrounded by electrode housings. Some of the technologies that will be demonstrated by this facility include a novel TM charge control scheme based on ultraviolet LEDs, an all-optical TM position and attitude sensor, and drift mode operation. This presentation will describe the design of the torsion pendulum facility, its current acceleration noise performance, and the status of the GRS technologies under development.

Organization model for Mobile Wireless Sensor Networks inspired in Artificial Bee Colony

NASA Astrophysics Data System (ADS)

Freire Roberto, Guilherme; Castilho Maschi, Luis Fernando; Pigatto, Daniel Fernando; Jaquie Castelo Branco, Kalinka Regina Lucas; Alves Neves, Leandro; Montez, Carlos; Sandro Roschildt Pinto, Alex

2015-01-01

The purpose of this study is to find a self-organizing model for MWSN based on bee colonies in order to reduce the number of messages transmitted among nodes, and thus reduce the overall consumption energy while maintaining the efficiency of message delivery. The results obtained in this article are originated from simulations carried out with SINALGO software, which demonstrates the effectiveness of the proposed approach. The BeeAODV (Bee Ad-Hoc On Demand Distance Vector) proposed in this paper allows to considerably reduce message exchanges whether compared to AODV (Ad-Hoc On Demand Distance Vector).

An integrated optical sensor for GMAW feedback control

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

Taylor, P.L.; Watkins, A.D.; Larsen, E.D.

1992-08-01

The integrated optical sensor (IOS) is a multifunction feedback control sensor for arc welding, that is computer automated and independent of significant operator interaction. It is based on three major ``off-the-shelf`` components: a charged coupled device (CCD) camera, a diode laser, and a processing computer. The sensor head is compact and lightweight to avoid interference with weld head mobility, hardened to survive the harsh operating environment, and free of specialized cooling and power requirements. The sensor is positioned behind the GMAW torch and measures weld pool position and width, standoff distance, and postweld centerline cooling rate. Weld pool position andmore » width are used in a feedback loop, by the weld controller, to track the weld pool relative to the weld joint, thus allowing compensation for such phenomena as arc blow. Sensor stand off distance is used in a feedback loop to control the contact tip to base metal distance during the welding process. Cooling rate information is used to infer the final metallurgical state of the weld bead and heat affected zone, thereby providing a means of controlling post weld mechanical properties.« less

An integrated optical sensor for GMAW feedback control

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

Taylor, P.L.; Watkins, A.D.; Larsen, E.D.

1992-01-01

The integrated optical sensor (IOS) is a multifunction feedback control sensor for arc welding, that is computer automated and independent of significant operator interaction. It is based on three major off-the-shelf'' components: a charged coupled device (CCD) camera, a diode laser, and a processing computer. The sensor head is compact and lightweight to avoid interference with weld head mobility, hardened to survive the harsh operating environment, and free of specialized cooling and power requirements. The sensor is positioned behind the GMAW torch and measures weld pool position and width, standoff distance, and postweld centerline cooling rate. Weld pool position andmore » width are used in a feedback loop, by the weld controller, to track the weld pool relative to the weld joint, thus allowing compensation for such phenomena as arc blow. Sensor stand off distance is used in a feedback loop to control the contact tip to base metal distance during the welding process. Cooling rate information is used to infer the final metallurgical state of the weld bead and heat affected zone, thereby providing a means of controlling post weld mechanical properties.« less

Novel Approach for Positioning Sensor Lead Wires on SiC-Based Monolithic Ceramic and FRCMC Components/Subcomponents Having Flat and Curved Surfaces

NASA Technical Reports Server (NTRS)

Kiser, J. Douglas; Singh, Mrityunjay; Lei, Jin-Fen; Martin, Lisa C.

1999-01-01

A novel attachment approach for positioning sensor lead wires on silicon carbide-based monolithic ceramic and fiber reinforced ceramic matrix composite (FRCMC) components has been developed. This approach is based on an affordable, robust ceramic joining technology, named ARCJoinT, which was developed for the joining of silicon carbide-based ceramic and fiber reinforced composites. The ARCJoinT technique has previously been shown to produce joints with tailorable thickness and good high temperature strength. In this study, silicon carbide-based ceramic and FRCMC attachments of different shapes and sizes were joined onto silicon carbide fiber reinforced silicon carbide matrix (SiC/ SiC) composites having flat and curved surfaces. Based on results obtained in previous joining studies. the joined attachments should maintain their mechanical strength and integrity at temperatures up to 1350 C in air. Therefore they can be used to position and secure sensor lead wires on SiC/SiC components that are being tested in programs that are focused on developing FRCMCs for a number of demanding high temperature applications in aerospace and ground-based systems. This approach, which is suitable for installing attachments on large and complex shaped monolithic ceramic and composite components, should enhance the durability of minimally intrusive high temperature sensor systems. The technology could also be used to reinstall attachments on ceramic components that were damaged in service.

Recent advances in light-responsive on-demand drug-delivery systems

PubMed Central

Linsley, Chase S; Wu, Benjamin M

2017-01-01

The convergence of wearable sensors and personalized medicine enhance the ability to sense and control the drug composition and dosage, as well as location and timing of administration. To date, numerous stimuli-triggered smart drug-delivery systems have been developed to detect changes in light, pH, temperature, biomolecules, electric field, magnetic field, ultrasound and mechanical forces. This review examines the major advances within the last 5 years for the three most common light-responsive drug delivery-on-demand strategies: photochemical, photoisomerization and photothermal. Examples are highlighted to illustrate progress of each strategy in drug delivery applications, and key limitations are identified to motivate future research to advance this important field. PMID:28088880

Recent advances in light-responsive on-demand drug-delivery systems.

PubMed

Linsley, Chase S; Wu, Benjamin M

2017-02-01

The convergence of wearable sensors and personalized medicine enhance the ability to sense and control the drug composition and dosage, as well as location and timing of administration. To date, numerous stimuli-triggered smart drug-delivery systems have been developed to detect changes in light, pH, temperature, biomolecules, electric field, magnetic field, ultrasound and mechanical forces. This review examines the major advances within the last 5 years for the three most common light-responsive drug delivery-on-demand strategies: photochemical, photoisomerization and photothermal. Examples are highlighted to illustrate progress of each strategy in drug delivery applications, and key limitations are identified to motivate future research to advance this important field.

Highly stretchable and ultrathin nanopaper composites for epidermal strain sensors.

PubMed

Sun, Jingyao; Zhao, Yanan; Yang, Zhaogang; Shen, Jingjing; Cabrera, Eusebio; Lertola, Matthew J; Yang, Willie; Zhang, Dan; Benatar, Avi; Castro, Jose M; Wu, Daming; Lee, L James

2018-08-31

Multifunctional electronics are attracting great interest with the increasing demand and fast development of wearable electronic devices. Here, we describe an epidermal strain sensor based on an all-carbon conductive network made from multi-walled carbon nanotubes (MWCNTs) impregnated with poly(dimethyl siloxane) (PDMS) matrix through a vacuum filtration process. An ultrasonication treatment was performed to complete the penetration of PDMS resin in seconds. The entangled and overlapped MWCNT network largely enhances the electrical conductivity (1430 S m -1 ), uniformity (remaining stable on different layers), reliable sensing range (up to 80% strain), and cyclic stability of the strain sensor. The homogeneous dispersion of MWCNTs within the PDMS matrix leads to a strong interaction between the two phases and greatly improves the mechanical stability (ca. 160% strain at fracture). The flexible, reversible and ultrathin (<100 μm) film can be directly attached on human skin as epidermal strain sensors for high accuracy and real-time human motion detection.

New Research on MEMS Acoustic Vector Sensors Used in Pipeline Ground Markers

PubMed Central

Song, Xiaopeng; Jian, Zeming; Zhang, Guojun; Liu, Mengran; Guo, Nan; Zhang, Wendong

2015-01-01

According to the demands of current pipeline detection systems, the above-ground marker (AGM) system based on sound detection principle has been a major development trend in pipeline technology. A novel MEMS acoustic vector sensor for AGM systems which has advantages of high sensitivity, high signal-to-noise ratio (SNR), and good low frequency performance has been put forward. Firstly, it is presented that the frequency of the detected sound signal is concentrated in a lower frequency range, and the sound attenuation is relatively low in soil. Secondly, the MEMS acoustic vector sensor structure and basic principles are introduced. Finally, experimental tests are conducted and the results show that in the range of 0°∼90°, when r = 5 m, the proposed MEMS acoustic vector sensor can effectively detect sound signals in soil. The measurement errors of all angles are less than 5°. PMID:25609046

Gyrocopter-Based Remote Sensing Platform

NASA Astrophysics Data System (ADS)

Weber, I.; Jenal, A.; Kneer, C.; Bongartz, J.

2015-04-01

In this paper the development of a lightweight and highly modularized airborne sensor platform for remote sensing applications utilizing a gyrocopter as a carrier platform is described. The current sensor configuration consists of a high resolution DSLR camera for VIS-RGB recordings. As a second sensor modality, a snapshot hyperspectral camera was integrated in the aircraft. Moreover a custom-developed thermal imaging system composed of a VIS-PAN camera and a LWIR-camera is used for aerial recordings in the thermal infrared range. Furthermore another custom-developed highly flexible imaging system for high resolution multispectral image acquisition with up to six spectral bands in the VIS-NIR range is presented. The performance of the overall system was tested during several flights with all sensor modalities and the precalculated demands with respect to spatial resolution and reliability were validated. The collected data sets were georeferenced, georectified, orthorectified and then stitched to mosaics.

Oxygen sensor signal validation for the safety of the rebreather diver.

PubMed

Sieber, Arne; L'abbate, Antonio; Bedini, Remo

2009-03-01

In electronically controlled, closed-circuit rebreather diving systems, the partial pressure of oxygen inside the breathing loop is controlled with three oxygen sensors, a microcontroller and a solenoid valve - critical components that may fail. State-of-the-art detection of sensor failure, based on a voting algorithm, may fail under circumstances where two or more sensors show the same but incorrect values. The present paper details a novel rebreather controller that offers true sensor-signal validation, thus allowing efficient and reliable detection of sensor failure. The core components of this validation system are two additional solenoids, which allow an injection of oxygen or diluent gas directly across the sensor membrane.

A Human Serum-Based Enzyme-Free Continuous Glucose Monitoring Technique Using a Needle-Type Bio-Layer Interference Sensor.

PubMed

Seo, Dongmin; Paek, Sung-Ho; Oh, Sangwoo; Seo, Sungkyu; Paek, Se-Hwan

2016-09-24

The incidence of diabetes is continually increasing, and by 2030, it is expected to have increased by 69% and 20% in underdeveloped and developed countries, respectively. Therefore, glucose sensors are likely to remain in high demand in medical device markets. For the current study, we developed a needle-type bio-layer interference (BLI) sensor that can continuously monitor glucose levels. Using dialysis procedures, we were able to obtain hypoglycemic samples from commercial human serum. These dialysis-derived samples, alongside samples of normal human serum were used to evaluate the utility of the sensor for the detection of the clinical interest range of glucose concentrations (70-200 mg/dL), revealing high system performance for a wide glycemic state range (45-500 mg/dL). Reversibility and reproducibility were also tested over a range of time spans. Combined with existing BLI system technology, this sensor holds great promise for use as a wearable online continuous glucose monitoring system for patients in a hospital setting.

Multivariable Sensors for Ubiquitous Monitoring of Gases in the Era of Internet of Things and Industrial Internet.

PubMed

Potyrailo, Radislav A

2016-10-12

Modern gas monitoring scenarios for medical diagnostics, environmental surveillance, industrial safety, and other applications demand new sensing capabilities. This Review provides analysis of development of new generation of gas sensors based on the multivariable response principles. Design criteria of these individual sensors involve a sensing material with multiresponse mechanisms to different gases and a multivariable transducer with independent outputs to recognize these different gas responses. These new sensors quantify individual components in mixtures, reject interferences, and offer more stable response over sensor arrays. Such performance is attractive when selectivity advantages of classic gas chromatography, ion mobility, and mass spectrometry instruments are canceled by requirements for no consumables, low power, low cost, and unobtrusive form factors for Internet of Things, Industrial Internet, and other applications. This Review is concluded with a perspective for future needs in fundamental and applied aspects of gas sensing and with the 2025 roadmap for ubiquitous gas monitoring.

Cross-Layer Algorithms for QoS Enhancement in Wireless Multimedia Sensor Networks

NASA Astrophysics Data System (ADS)

Saxena, Navrati; Roy, Abhishek; Shin, Jitae

A lot of emerging applications like advanced telemedicine and surveillance systems, demand sensors to deliver multimedia content with precise level of QoS enhancement. Minimizing energy in sensor networks has been a much explored research area but guaranteeing QoS over sensor networks still remains an open issue. In this letter we propose a cross-layer approach combining Network and MAC layers, for QoS enhancement in wireless multimedia sensor networks. In the network layer a statistical estimate of sensory QoS parameters is performed and a nearoptimal genetic algorithmic solution is proposed to solve the NP-complete QoS-routing problem. On the other hand the objective of the proposed MAC algorithm is to perform the QoS-based packet classification and automatic adaptation of the contention window. Simulation results demonstrate that the proposed protocol is capable of providing lower delay and better throughput, at the cost of reasonable energy consumption, in comparison with other existing sensory QoS protocols.

Analyte-driven switching of DNA charge transport: de novo creation of electronic sensors for an early lung cancer biomarker.

PubMed

Thomas, Jason M; Chakraborty, Banani; Sen, Dipankar; Yu, Hua-Zhong

2012-08-22

A general approach is described for the de novo design and construction of aptamer-based electrochemical biosensors, for potentially any analyte of interest (ranging from small ligands to biological macromolecules). As a demonstration of the approach, we report the rapid development of a made-to-order electronic sensor for a newly reported early biomarker for lung cancer (CTAP III/NAP2). The steps include the in vitro selection and characterization of DNA aptamer sequences, design and biochemical testing of wholly DNA sensor constructs, and translation to a functional electrode-bound sensor format. The working principle of this distinct class of electronic biosensors is the enhancement of DNA-mediated charge transport in response to analyte binding. We first verify such analyte-responsive charge transport switching in solution, using biochemical methods; successful sensor variants were then immobilized on gold electrodes. We show that using these sensor-modified electrodes, CTAP III/NAP2 can be detected with both high specificity and sensitivity (K(d) ~1 nM) through a direct electrochemical reading. To investigate the underlying basis of analyte binding-induced conductivity switching, we carried out Förster Resonance Energy Transfer (FRET) experiments. The FRET data establish that analyte binding-induced conductivity switching in these sensors results from very subtle structural/conformational changes, rather than large scale, global folding events. The implications of this finding are discussed with respect to possible charge transport switching mechanisms in electrode-bound sensors. Overall, the approach we describe here represents a unique design principle for aptamer-based electrochemical sensors; its application should enable rapid, on-demand access to a class of portable biosensors that offer robust, inexpensive, and operationally simplified alternatives to conventional antibody-based immunoassays.

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

NASA Technical Reports Server (NTRS)

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

2011-01-01

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

Flow Control in Wells Turbines for Harnessing Maximum Wave Power.

PubMed

Lekube, Jon; Garrido, Aitor J; Garrido, Izaskun; Otaola, Erlantz; Maseda, Javier

2018-02-10

Oceans, and particularly waves, offer a huge potential for energy harnessing all over the world. Nevertheless, the performance of current energy converters does not yet allow us to use the wave energy efficiently. However, new control techniques can improve the efficiency of energy converters. In this sense, the plant sensors play a key role within the control scheme, as necessary tools for parameter measuring and monitoring that are then used as control input variables to the feedback loop. Therefore, the aim of this work is to manage the rotational speed control loop in order to optimize the output power. With the help of outward looking sensors, a Maximum Power Point Tracking (MPPT) technique is employed to maximize the system efficiency. Then, the control decisions are based on the pressure drop measured by pressure sensors located along the turbine. A complete wave-to-wire model is developed so as to validate the performance of the proposed control method. For this purpose, a novel sensor-based flow controller is implemented based on the different measured signals. Thus, the performance of the proposed controller has been analyzed and compared with a case of uncontrolled plant. The simulations demonstrate that the flow control-based MPPT strategy is able to increase the output power, and they confirm both the viability and goodness.

Flow Control in Wells Turbines for Harnessing Maximum Wave Power

PubMed Central

Garrido, Aitor J.; Garrido, Izaskun; Otaola, Erlantz; Maseda, Javier

2018-01-01

Oceans, and particularly waves, offer a huge potential for energy harnessing all over the world. Nevertheless, the performance of current energy converters does not yet allow us to use the wave energy efficiently. However, new control techniques can improve the efficiency of energy converters. In this sense, the plant sensors play a key role within the control scheme, as necessary tools for parameter measuring and monitoring that are then used as control input variables to the feedback loop. Therefore, the aim of this work is to manage the rotational speed control loop in order to optimize the output power. With the help of outward looking sensors, a Maximum Power Point Tracking (MPPT) technique is employed to maximize the system efficiency. Then, the control decisions are based on the pressure drop measured by pressure sensors located along the turbine. A complete wave-to-wire model is developed so as to validate the performance of the proposed control method. For this purpose, a novel sensor-based flow controller is implemented based on the different measured signals. Thus, the performance of the proposed controller has been analyzed and compared with a case of uncontrolled plant. The simulations demonstrate that the flow control-based MPPT strategy is able to increase the output power, and they confirm both the viability and goodness. PMID:29439408

Knowledge base and sensor bus messaging service architecture for critical tsunami warning and decision-support

NASA Astrophysics Data System (ADS)

Sabeur, Z. A.; Wächter, J.; Middleton, S. E.; Zlatev, Z.; Häner, R.; Hammitzsch, M.; Loewe, P.

2012-04-01

The intelligent management of large volumes of environmental monitoring data for early tsunami warning requires the deployment of robust and scalable service oriented infrastructure that is supported by an agile knowledge-base for critical decision-support In the TRIDEC project (TRIDEC 2010-2013), a sensor observation service bus of the TRIDEC system is being developed for the advancement of complex tsunami event processing and management. Further, a dedicated TRIDEC system knowledge-base is being implemented to enable on-demand access to semantically rich OGC SWE compliant hydrodynamic observations and operationally oriented meta-information to multiple subscribers. TRIDEC decision support requires a scalable and agile real-time processing architecture which enables fast response to evolving subscribers requirements as the tsunami crisis develops. This is also achieved with the support of intelligent processing services which specialise in multi-level fusion methods with relevance feedback and deep learning. The TRIDEC knowledge base development work coupled with that of the generic sensor bus platform shall be presented to demonstrate advanced decision-support with situation awareness in context of tsunami early warning and crisis management.

Weld Nugget Temperature Control in Thermal Stir Welding

NASA Technical Reports Server (NTRS)

Ding, R. Jeffrey (Inventor)

2014-01-01

A control system for a thermal stir welding system is provided. The control system includes a sensor and a controller. The sensor is coupled to the welding system's containment plate assembly and generates signals indicative of temperature of a region adjacent and parallel to the welding system's stir rod. The controller is coupled to the sensor and generates at least one control signal using the sensor signals indicative of temperature. The controller is also coupled to the welding system such that at least one of rotational speed of the stir rod, heat supplied by the welding system's induction heater, and feed speed of the welding system's weld material feeder are controlled based on the control signal(s).

Flexible and disposable plasmonic refractive index sensor using nanoimprint lithography

NASA Astrophysics Data System (ADS)

Mohapatra, Saswat; Moirangthem, Rakesh S.

2018-03-01

Nanostructure based plasmonic sensors are highly demanding in various areas due to their label-free and real-time detection capability. In this work, we developed an inexpensive flexible plasmonic sensor using optical disc nanograting via soft UV-nanoimprint lithography (UV-NIL). The polydimethylsiloxane (PDMS) stamp was used to transfer the nanograting structure from digital versatile discs (DVDs) to flexible and transparent polyethylene terephthalate (PET) substrate. Further, the plasmonic sensing substrate was obtained after coating a gold thin film on the top of the imprinted sample. The surface plasmon resonance (SPR) modes excited on gold coated nanograting structure appeared as a dip in the reflectance spectra measured at normal incident of white light in ambient air medium. Electromagnetic simulation based on finite element method (FEM) was used to understand and analyze the excited SPR modes and it is a very close agreement with the experimental results. The bulk refractive index (RI) sensing was performed by the sensor chip using water-glycerol mixture with different concentrations. Experimentally, the bulk RI sensitivity was found to be 797+/-17 nm/RIU.

A Field Programmable Gate Array-Based Reconfigurable Smart-Sensor Network for Wireless Monitoring of New Generation Computer Numerically Controlled Machines

PubMed Central

Moreno-Tapia, Sandra Veronica; Vera-Salas, Luis Alberto; Osornio-Rios, Roque Alfredo; Dominguez-Gonzalez, Aurelio; Stiharu, Ion; de Jesus Romero-Troncoso, Rene

2010-01-01

Computer numerically controlled (CNC) machines have evolved to adapt to increasing technological and industrial requirements. To cover these needs, new generation machines have to perform monitoring strategies by incorporating multiple sensors. Since in most of applications the online Processing of the variables is essential, the use of smart sensors is necessary. The contribution of this work is the development of a wireless network platform of reconfigurable smart sensors for CNC machine applications complying with the measurement requirements of new generation CNC machines. Four different smart sensors are put under test in the network and their corresponding signal processing techniques are implemented in a Field Programmable Gate Array (FPGA)-based sensor node. PMID:22163602

A field programmable gate array-based reconfigurable smart-sensor network for wireless monitoring of new generation computer numerically controlled machines.

PubMed

Moreno-Tapia, Sandra Veronica; Vera-Salas, Luis Alberto; Osornio-Rios, Roque Alfredo; Dominguez-Gonzalez, Aurelio; Stiharu, Ion; Romero-Troncoso, Rene de Jesus

2010-01-01

Computer numerically controlled (CNC) machines have evolved to adapt to increasing technological and industrial requirements. To cover these needs, new generation machines have to perform monitoring strategies by incorporating multiple sensors. Since in most of applications the online Processing of the variables is essential, the use of smart sensors is necessary. The contribution of this work is the development of a wireless network platform of reconfigurable smart sensors for CNC machine applications complying with the measurement requirements of new generation CNC machines. Four different smart sensors are put under test in the network and their corresponding signal processing techniques are implemented in a Field Programmable Gate Array (FPGA)-based sensor node.

Sensor fault detection and recovery in satellite attitude control

NASA Astrophysics Data System (ADS)

Nasrolahi, Seiied Saeed; Abdollahi, Farzaneh

2018-04-01

This paper proposes an integrated sensor fault detection and recovery for the satellite attitude control system. By introducing a nonlinear observer, the healthy sensor measurements are provided. Considering attitude dynamics and kinematic, a novel observer is developed to detect the fault in angular rate as well as attitude sensors individually or simultaneously. There is no limit on type and configuration of attitude sensors. By designing a state feedback based control signal and Lyapunov stability criterion, the uniformly ultimately boundedness of tracking errors in the presence of sensor faults is guaranteed. Finally, simulation results are presented to illustrate the performance of the integrated scheme.

Gaming control using a wearable and wireless EEG-based brain-computer interface device with novel dry foam-based sensors

PubMed Central

2012-01-01

A brain-computer interface (BCI) is a communication system that can help users interact with the outside environment by translating brain signals into machine commands. The use of electroencephalographic (EEG) signals has become the most common approach for a BCI because of their usability and strong reliability. Many EEG-based BCI devices have been developed with traditional wet- or micro-electro-mechanical-system (MEMS)-type EEG sensors. However, those traditional sensors have uncomfortable disadvantage and require conductive gel and skin preparation on the part of the user. Therefore, acquiring the EEG signals in a comfortable and convenient manner is an important factor that should be incorporated into a novel BCI device. In the present study, a wearable, wireless and portable EEG-based BCI device with dry foam-based EEG sensors was developed and was demonstrated using a gaming control application. The dry EEG sensors operated without conductive gel; however, they were able to provide good conductivity and were able to acquire EEG signals effectively by adapting to irregular skin surfaces and by maintaining proper skin-sensor impedance on the forehead site. We have also demonstrated a real-time cognitive stage detection application of gaming control using the proposed portable device. The results of the present study indicate that using this portable EEG-based BCI device to conveniently and effectively control the outside world provides an approach for researching rehabilitation engineering. PMID:22284235

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.

Metal-Insulator-Metal-Based Plasmonic Metamaterial Absorbers at Visible and Infrared Wavelengths: A Review.

PubMed

Ogawa, Shinpei; Kimata, Masafumi

2018-03-20

Electromagnetic wave absorbers have been investigated for many years with the aim of achieving high absorbance and tunability of both the absorption wavelength and the operation mode by geometrical control, small and thin absorber volume, and simple fabrication. There is particular interest in metal-insulator-metal-based plasmonic metamaterial absorbers (MIM-PMAs) due to their complete fulfillment of these demands. MIM-PMAs consist of top periodic micropatches, a middle dielectric layer, and a bottom reflector layer to generate strong localized surface plasmon resonance at absorption wavelengths. In particular, in the visible and infrared (IR) wavelength regions, a wide range of applications is expected, such as solar cells, refractive index sensors, optical camouflage, cloaking, optical switches, color pixels, thermal IR sensors, IR microscopy and gas sensing. The promising properties of MIM-PMAs are attributed to the simple plasmonic resonance localized at the top micropatch resonators formed by the MIMs. Here, various types of MIM-PMAs are reviewed in terms of their historical background, basic physics, operation mode design, and future challenges to clarify their underlying basic design principles and introduce various applications. The principles presented in this review paper can be applied to other wavelength regions such as the ultraviolet, terahertz, and microwave regions.

Metal-Insulator-Metal-Based Plasmonic Metamaterial Absorbers at Visible and Infrared Wavelengths: A Review

PubMed Central

Ogawa, Shinpei; Kimata, Masafumi

2018-01-01

Electromagnetic wave absorbers have been investigated for many years with the aim of achieving high absorbance and tunability of both the absorption wavelength and the operation mode by geometrical control, small and thin absorber volume, and simple fabrication. There is particular interest in metal-insulator-metal-based plasmonic metamaterial absorbers (MIM-PMAs) due to their complete fulfillment of these demands. MIM-PMAs consist of top periodic micropatches, a middle dielectric layer, and a bottom reflector layer to generate strong localized surface plasmon resonance at absorption wavelengths. In particular, in the visible and infrared (IR) wavelength regions, a wide range of applications is expected, such as solar cells, refractive index sensors, optical camouflage, cloaking, optical switches, color pixels, thermal IR sensors, IR microscopy and gas sensing. The promising properties of MIM-PMAs are attributed to the simple plasmonic resonance localized at the top micropatch resonators formed by the MIMs. Here, various types of MIM-PMAs are reviewed in terms of their historical background, basic physics, operation mode design, and future challenges to clarify their underlying basic design principles and introduce various applications. The principles presented in this review paper can be applied to other wavelength regions such as the ultraviolet, terahertz, and microwave regions. PMID:29558454

Performance monitoring algorithm for optimizing electrical power generated by using photovoltaic system

NASA Astrophysics Data System (ADS)

Pradeep, M. V. K.; Balbir, S. M. S.; Norani, M. M.

2016-11-01

Demand for electricity in Malaysia has seen a substantial hike in light of the nation's rapid economic development. The current method of generating electricity is through the combustion of fossil fuels which has led to the detrimental effects on the environment besides causing social and economic outbreaks due to its highly volatile prices. Thus the need for a sustainable energy source is paramount and one that is quickly gaining acceptance is solar energy. However, due to the various environmental and geographical factors that affect the generation of solar electricity, the capability of solar electricity generating system (SEGS) is unable to compete with the high conversion efficiencies of conventional energy sources. In order to effectively monitor SEGS, this study is proposing a performance monitoring system that is capable of detecting drops in the system's performance for parallel networks through a diagnostic mechanism. The performance monitoring system consists of microcontroller connected to relevant sensors for data acquisition. The acquired data is transferred to a microcomputer for software based monitoring and analysis. In order to enhance the interception of sunlight by the SEGS, a sensor based sun tracking system is interfaced to the same controller to allow the PV to maneuver itself autonomously to an angle of maximum sunlight exposure.

Optimized star sensors laboratory calibration method using a regularization neural network.

PubMed

Zhang, Chengfen; Niu, Yanxiong; Zhang, Hao; Lu, Jiazhen

2018-02-10

High-precision ground calibration is essential to ensure the performance of star sensors. However, the complex distortion and multi-error coupling have brought great difficulties to traditional calibration methods, especially for large field of view (FOV) star sensors. Although increasing the complexity of models is an effective way to improve the calibration accuracy, it significantly increases the demand for calibration data. In order to achieve high-precision calibration of star sensors with large FOV, a novel laboratory calibration method based on a regularization neural network is proposed. A multi-layer structure neural network is designed to represent the mapping of the star vector and the corresponding star point coordinate directly. To ensure the generalization performance of the network, regularization strategies are incorporated into the net structure and the training algorithm. Simulation and experiment results demonstrate that the proposed method can achieve high precision with less calibration data and without any other priori information. Compared with traditional methods, the calibration error of the star sensor decreased by about 30%. The proposed method can satisfy the precision requirement for large FOV star sensors.

Plasmonic Waveguide Coupled Ring Cavity for a Non-Resonant Type Refractive Index Sensor.

PubMed

Kwon, Soon-Hong

2017-11-03

Sensitive refractive index sensors with small footprints have been studied to allow the integration of a large number of sensors into a tiny chip for bio/chemical applications. In particular, resonant-type index sensors based on various micro/nanocavities, which use a resonant wavelength dependence on the refractive index of the analyte, have been developed. However, the spectral linewidth of the resonance, which becomes the resolution limit, is considerably large in plasmonic cavities due to the large absorption loss of metals. Therefore, there is demand for a new type of plasmonic refractive index sensor that is not limited by the linewidth of the cavity. We propose a new type of plasmonic index sensors consisting of a channel waveguide and a ring cavity. Two emissions from the ring cavity in both directions of the waveguide couple with a reflection phase difference depending on the length of a closed right arm with a reflecting boundary. Therefore, the output power dramatically and sensitively changes as a function of the refractive index of the analyte filling the waveguide.

An Electromagnetic/Capacitive Composite Sensor for Testing of Thermal Barrier Coatings

PubMed Central

Ren, Yuan; Pan, Mengchun; Chen, Dixiang; Tian, Wugang

2018-01-01

Thermal barrier coatings (TBCs) can significantly reduce the operating temperature of the aeroengine turbine blade substrate, and their testing technology is very urgently demanded. Due to their complex multi-layer structure, it is hard to evaluate TBCs with a single function sensor. In this paper, an electromagnetic/capacitive composite sensor is proposed for the testing of thermal barrier coatings. The dielectric material is tested with planar capacitor, and the metallic material is tested with electromagnetic coils. Then, the comprehensive test and evaluation of thermal barrier coating system can be realized. The sensor is optimized by means of theoretical and simulation analysis, and the interaction between the planar capacitor and the electromagnetic coil is studied. The experimental system is built based on an impedance analyser and multiplex unit to evaluate the performance of the composite sensor. The transimpedances and capacitances are measured under different coating parameters, such as thickness and permittivity of top coating as well as bond layer conductivity. The experimental results agree with the simulation analysis, and the feasibility of the sensor is proved. PMID:29783746

Plasmonic Waveguide Coupled Ring Cavity for a Non-Resonant Type Refractive Index Sensor

PubMed Central

Kwon, Soon-Hong

2017-01-01

Sensitive refractive index sensors with small footprints have been studied to allow the integration of a large number of sensors into a tiny chip for bio/chemical applications. In particular, resonant-type index sensors based on various micro/nanocavities, which use a resonant wavelength dependence on the refractive index of the analyte, have been developed. However, the spectral linewidth of the resonance, which becomes the resolution limit, is considerably large in plasmonic cavities due to the large absorption loss of metals. Therefore, there is demand for a new type of plasmonic refractive index sensor that is not limited by the linewidth of the cavity. We propose a new type of plasmonic index sensors consisting of a channel waveguide and a ring cavity. Two emissions from the ring cavity in both directions of the waveguide couple with a reflection phase difference depending on the length of a closed right arm with a reflecting boundary. Therefore, the output power dramatically and sensitively changes as a function of the refractive index of the analyte filling the waveguide. PMID:29099740

Two-layer wireless distributed sensor/control network based on RF

NASA Astrophysics Data System (ADS)

Feng, Li; Lin, Yuchi; Zhou, Jingjing; Dong, Guimei; Xia, Guisuo

2006-11-01

A project of embedded Wireless Distributed Sensor/Control Network (WDSCN) based on RF is presented after analyzing the disadvantages of traditional measure and control system. Because of high-cost and complexity, such wireless techniques as Bluetooth and WiFi can't meet the needs of WDSCN. The two-layer WDSCN is designed based on RF technique, which operates in the ISM free frequency channel with low power and high transmission speed. Also the network is low cost, portable and moveable, integrated with the technologies of computer network, sensor, microprocessor and wireless communications. The two-layer network topology is selected in the system; a simple but efficient self-organization net protocol is designed to fit the periodic data collection, event-driven and store-and-forward. Furthermore, adaptive frequency hopping technique is adopted for anti-jamming apparently. The problems about power reduction and synchronization of data in wireless system are solved efficiently. Based on the discussion above, a measure and control network is set up to control such typical instruments and sensors as temperature sensor and signal converter, collect data, and monitor environmental parameters around. This system works well in different rooms. Experiment results show that the system provides an efficient solution to WDSCN through wireless links, with high efficiency, low power, high stability, flexibility and wide working range.

Chemical Sensors Based on Metal Oxide Nanostructures

NASA Technical Reports Server (NTRS)

Hunter, Gary W.; Xu, Jennifer C.; Evans, Laura J.; VanderWal, Randy L.; Berger, Gordon M.; Kulis, Mike J.; Liu, Chung-Chiun

2006-01-01

This paper is an overview of sensor development based on metal oxide nanostructures. While nanostructures such as nanorods show significan t potential as enabling materials for chemical sensors, a number of s ignificant technical challenges remain. The major issues addressed in this work revolve around the ability to make workable sensors. This paper discusses efforts to address three technical barriers related t o the application of nanostructures into sensor systems: 1) Improving contact of the nanostructured materials with electrodes in a microse nsor structure; 2) Controling nanostructure crystallinity to allow co ntrol of the detection mechanism; and 3) Widening the range of gases that can be detected by using different nanostructured materials. It is concluded that while this work demonstrates useful tools for furt her development, these are just the beginning steps towards realizati on of repeatable, controlled sensor systems using oxide based nanostr uctures.

Si light-emitting device in integrated photonic CMOS ICs

NASA Astrophysics Data System (ADS)

Xu, Kaikai; Snyman, Lukas W.; Aharoni, Herzl

2017-07-01

The motivation for integrated Si optoelectronics is the creation of low-cost photonics for mass-market applications. Especially, the growing demand for sensitive biochemical sensors in the environmental control or medicine leads to the development of integrated high resolution sensors. Here CMOS-compatible Si light-emitting device structures are presented for investigating the effect of various depletion layer profiles and defect engineering on the photonic transition in the 1.4-2.8 eV. A novel Si device is proposed to realize both a two-terminal Si-diode light-emitting device and a three-terminal Si gate-controlled diode light-emitting device in the same device structure. In addition to the spectral analysis, differences between two-terminal and three-terminal devices are discussed, showing the light emission efficiency change. The proposed Si optical source may find potential applications in micro-photonic systems and micro-optoelectro-mechanical systems (MOEMS) in CMOS integrated circuitry.

Data management for biofied building

NASA Astrophysics Data System (ADS)

Matsuura, Kohta; Mita, Akira

2015-03-01

Recently, Smart houses have been studied by many researchers to satisfy individual demands of residents. However, they are not feasible yet as they are very costly and require many sensors to be embedded into houses. Therefore, we suggest "Biofied Building". In Biofied Building, sensor agent robots conduct sensing, actuation, and control in their house. The robots monitor many parameters of human lives such as walking postures and emotion continuously. In this paper, a prototype network system and a data model for practical application for Biofied Building is pro-posed. In the system, functions of robots and servers are divided according to service flows in Biofield Buildings. The data model is designed to accumulate both the building data and the residents' data. Data sent from the robots and data analyzed in the servers are automatically registered into the database. Lastly, feasibility of this system is verified through lighting control simulation performed in an office space.

Testing low cost OEM CO2 sensors for outdoor ecological studies

NASA Astrophysics Data System (ADS)

Macintyre, C. M.; Risk, D. A.

2011-12-01

IR (Infrared) gas sensors are used extensively in CO2 research but price and power requirement often limits low-cost distributed sensing. In the past three years, sensors have been introduced to the industrial market at prices as low as $100 US for air-handling and automotive application. These inexpensive sensors are small in size, and have low power demand making them potentially ideal for low-cost distributed deployments. However, the sensors are only tested and calibrated for indoor use and for industrial standards and may not show their true potential for outdoor ecological studies. This poster summarizes the results of a sensor inter-comparison test, to document functionality, response time, electrical noise, precision, and accuracy, under varying moistures and temperatures broadly representative of a wide range of outdoor settings. The three selected sensors were placed in a closed loop system with a valving system using a LiCor Li-7000 as reference, controlled by a CR1000 datalogger that controlled CO2 and moisture concentrations content within the cell on the basis of LiCor readings. To achieve different temperatures, the tests were repeated at room temperature, inside a freezer (-18°C) and incubator (40°C). The tests involved repeatedly stepping the sensors from 2000 ppm CO2 to 400 ppm CO2 in 200 ppm or 400 ppm increments, at various moisture contents, and under the various temperature regimes. Vaisala 222 and 343 sensors were also part of the test group as comparators, as both are used widely in ecological research. The OEM sensors displayed good linearity, fast response time, and results comparable to Vaisala probes. In most cases the sensors performed beyond our expectations with notably less electrical noise than the Vaisala sensors and excellent power thriftiness. Some sensors showed better response to extreme moisture and temperature conditions. Provided that suitable protective embodiments were built around them, and that they are deployed in an environment suiting their tolerance limits, most of the tested sensors would be suitable as low-cost alternatives to sensors currently being sold for outdoor ecological studies.

Description of New Inflatable/Rigidizable Hexapod Structure Testbed for Shape and Vibration Control

NASA Technical Reports Server (NTRS)

Adetona, O.; Keel, L. H.; Horta, L. G.; Cadogan, D. P.; Sapna, G. H.; Scarborough, S. E.

2002-01-01

Larger and more powerful space based instruments are needed to meet increasingly sophisticated scientific demand. To support this need, concepts for telescopes with apertures of 100 meters are being investigated, but the required technologies are not in hand today. Due to the capacity limits of launch vehicles, the idea of deploying, erecting, or inflating large structures in space is being considered. Recently, rigidization concepts of large inflatable structures have demonstrated the capability of weight reductions of up to 50% from current concepts with packaging efficiencies near 80%. One of the important aspects of inflatable structures is vibration mitigation and line-of-sight control. Such control tasks are possible only after actuators/sensors are properly integrated into a rigidizable concept. To study these issues, we have developed an inflatable/rigidizable hexapod structure testbed. The testbed integrates state of the art piezo-electric self-sensing actuators into an inflatable/rigidizable structure and a flat membrane reflector. Using this testbed, we plan to experimentally demonstrate achievable vibration and line-of-sight control. This paper contains a description of the testbed and an outline of the test plan.

Roadmap on optical sensors.

PubMed

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

2017-08-01

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

Roadmap on optical sensors

NASA Astrophysics Data System (ADS)

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

2017-08-01

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

Joint Energy Supply and Routing Path Selection for Rechargeable Wireless Sensor Networks.

PubMed

Tang, Liangrui; Cai, Jinqi; Yan, Jiangyu; Zhou, Zhenyu

2018-06-17

The topic of network lifetime has been attracting much research attention because of its importance in prolonging the standing operation of battery-restricted wireless sensor networks, and the rechargeable wireless sensor network has emerged as a promising solution. In this paper, we propose a joint energy supply and routing path selection algorithm to extend the network lifetime based on an initiative power supply. We develop a two-stage energy replenishment strategy to supplement the energy consumption of nodes as much as possible. Furthermore, the influence of charging factors on the selection of next-hop nodes in data routing is considered. The simulation results show that our algorithm effectively prolong the network lifetime, and different demands of network delay and energy consumption can be obtained by dynamically adjusting parameters.

Design and implementation of visual-haptic assistive control system for virtual rehabilitation exercise and teleoperation manipulation.

PubMed

Veras, Eduardo J; De Laurentis, Kathryn J; Dubey, Rajiv

2008-01-01

This paper describes the design and implementation of a control system that integrates visual and haptic information to give assistive force feedback through a haptic controller (Omni Phantom) to the user. A sensor-based assistive function and velocity scaling program provides force feedback that helps the user complete trajectory following exercises for rehabilitation purposes. This system also incorporates a PUMA robot for teleoperation, which implements a camera and a laser range finder, controlled in real time by a PC, were implemented into the system to help the user to define the intended path to the selected target. The real-time force feedback from the remote robot to the haptic controller is made possible by using effective multithreading programming strategies in the control system design and by novel sensor integration. The sensor-based assistant function concept applied to teleoperation as well as shared control enhances the motion range and manipulation capabilities of the users executing rehabilitation exercises such as trajectory following along a sensor-based defined path. The system is modularly designed to allow for integration of different master devices and sensors. Furthermore, because this real-time system is versatile the haptic component can be used separately from the telerobotic component; in other words, one can use the haptic device for rehabilitation purposes for cases in which assistance is needed to perform tasks (e.g., stroke rehab) and also for teleoperation with force feedback and sensor assistance in either supervisory or automatic modes.

A Secure Routing Protocol for Wireless Sensor Networks Considering Secure Data Aggregation.

PubMed

Rahayu, Triana Mugia; Lee, Sang-Gon; Lee, Hoon-Jae

2015-06-26

The commonly unattended and hostile deployments of WSNs and their resource-constrained sensor devices have led to an increasing demand for secure energy-efficient protocols. Routing and data aggregation receive the most attention since they are among the daily network routines. With the awareness of such demand, we found that so far there has been no work that lays out a secure routing protocol as the foundation for a secure data aggregation protocol. We argue that the secure routing role would be rendered useless if the data aggregation scheme built on it is not secure. Conversely, the secure data aggregation protocol needs a secure underlying routing protocol as its foundation in order to be effectively optimal. As an attempt for the solution, we devise an energy-aware protocol based on LEACH and ESPDA that combines secure routing protocol and secure data aggregation protocol. We then evaluate its security effectiveness and its energy-efficiency aspects, knowing that there are always trade-off between both.

A Secure Routing Protocol for Wireless Sensor Networks Considering Secure Data Aggregation

PubMed Central

Rahayu, Triana Mugia; Lee, Sang-Gon; Lee, Hoon-Jae

2015-01-01

The commonly unattended and hostile deployments of WSNs and their resource-constrained sensor devices have led to an increasing demand for secure energy-efficient protocols. Routing and data aggregation receive the most attention since they are among the daily network routines. With the awareness of such demand, we found that so far there has been no work that lays out a secure routing protocol as the foundation for a secure data aggregation protocol. We argue that the secure routing role would be rendered useless if the data aggregation scheme built on it is not secure. Conversely, the secure data aggregation protocol needs a secure underlying routing protocol as its foundation in order to be effectively optimal. As an attempt for the solution, we devise an energy-aware protocol based on LEACH and ESPDA that combines secure routing protocol and secure data aggregation protocol. We then evaluate its security effectiveness and its energy-efficiency aspects, knowing that there are always trade-off between both. PMID:26131669

Advanced model-based FDIR techniques for aerospace systems: Today challenges and opportunities

NASA Astrophysics Data System (ADS)

Zolghadri, Ali

2012-08-01

This paper discusses some trends and recent advances in model-based Fault Detection, Isolation and Recovery (FDIR) for aerospace systems. The FDIR challenges range from pre-design and design stages for upcoming and new programs, to improvement of the performance of in-service flying systems. For space missions, optimization of flight conditions and safe operation is intrinsically related to GNC (Guidance, Navigation & Control) system of the spacecraft and includes sensors and actuators monitoring. Many future space missions will require autonomous proximity operations including fault diagnosis and the subsequent control and guidance recovery actions. For upcoming and future aircraft, one of the main issues is how early and robust diagnosis of some small and subtle faults could contribute to the overall optimization of aircraft design. This issue would be an important factor for anticipating the more and more stringent requirements which would come in force for future environmentally-friendlier programs. The paper underlines the reasons for a widening gap between the advanced scientific FDIR methods being developed by the academic community and technological solutions demanded by the aerospace industry.

Virtual environment assessment for laser-based vision surface profiling

NASA Astrophysics Data System (ADS)

ElSoussi, Adnane; Al Alami, Abed ElRahman; Abu-Nabah, Bassam A.

2015-03-01

Oil and gas businesses have been raising the demand from original equipment manufacturers (OEMs) to implement a reliable metrology method in assessing surface profiles of welds before and after grinding. This certainly mandates the deviation from the commonly used surface measurement gauges, which are not only operator dependent, but also limited to discrete measurements along the weld. Due to its potential accuracy and speed, the use of laser-based vision surface profiling systems have been progressively rising as part of manufacturing quality control. This effort presents a virtual environment that lends itself for developing and evaluating existing laser vision sensor (LVS) calibration and measurement techniques. A combination of two known calibration techniques is implemented to deliver a calibrated LVS system. System calibration is implemented virtually and experimentally to scan simulated and 3D printed features of known profiles, respectively. Scanned data is inverted and compared with the input profiles to validate the virtual environment capability for LVS surface profiling and preliminary assess the measurement technique for weld profiling applications. Moreover, this effort brings 3D scanning capability a step closer towards robust quality control applications in a manufacturing environment.

Applications of Payload Directed Flight

NASA Technical Reports Server (NTRS)

Ippolito, Corey; Fladeland, Matthew M.; Yeh, Yoo Hsiu

2009-01-01

Next generation aviation flight control concepts require autonomous and intelligent control system architectures that close control loops directly around payload sensors in manner more integrated and cohesive that in traditional autopilot designs. Research into payload directed flight control at NASA Ames Research Center is investigating new and novel architectures that can satisfy the requirements for next generation control and automation concepts for aviation. Tighter integration between sensor and machine requires definition of specific sensor-directed control modes to tie the sensor data directly into a vehicle control structures throughout the entire control architecture, from low-level stability- and control loops, to higher level mission planning and scheduling reasoning systems. Payload directed flight systems can thus provide guidance, navigation, and control for vehicle platforms hosting a suite of onboard payload sensors. This paper outlines related research into the field of payload directed flight; and outlines requirements and operating concepts for payload directed flight systems based on identified needs from the scientific literature.'

Welding technology transfer task/laser based weld joint tracking system for compressor girth welds

NASA Technical Reports Server (NTRS)

Looney, Alan

1991-01-01

Sensors to control and monitor welding operations are currently being developed at Marshall Space Flight Center. The laser based weld bead profiler/torch rotation sensor was modified to provide a weld joint tracking system for compressor girth welds. The tracking system features a precision laser based vision sensor, automated two-axis machine motion, and an industrial PC controller. The system benefits are elimination of weld repairs caused by joint tracking errors which reduces manufacturing costs and increases production output, simplification of tooling, and free costly manufacturing floor space.

Embedded Acoustic Sensor Array for Engine Fan Noise Source Diagnostic Test: Feasibility of Noise Telemetry via Wireless Smart Sensors

NASA Technical Reports Server (NTRS)

Zaman, Afroz; Bauch, Matthew; Raible, Daniel

2011-01-01

Aircraft engines have evolved into a highly complex system to meet ever-increasing demands. The evolution of engine technologies has primarily been driven by fuel efficiency, reliability, as well as engine noise concerns. One of the sources of engine noise is pressure fluctuations that are induced on the stator vanes. These local pressure fluctuations, once produced, propagate and coalesce with the pressure waves originating elsewhere on the stator to form a spinning pressure pattern. Depending on the duct geometry, air flow, and frequency of fluctuations, these spinning pressure patterns are self-sustaining and result in noise which eventually radiate to the far-field from engine. To investigate the nature of vane pressure fluctuations and the resulting engine noise, unsteady pressure signatures from an array of embedded acoustic sensors are recorded as a part of vane noise source diagnostics. Output time signatures from these sensors are routed to a control and data processing station adding complexity to the system and cable loss to the measured signal. "Smart" wireless sensors have data processing capability at the sensor locations which further increases the potential of wireless sensors. Smart sensors can process measured data locally and transmit only the important information through wireless communication. The aim of this wireless noise telemetry task was to demonstrate a single acoustic sensor wireless link for unsteady pressure measurement, and thus, establish the feasibility of distributed smart sensors scheme for aircraft engine vane surface unsteady pressure data transmission and characterization.

Statistical-QoS Guaranteed Energy Efficiency Optimization for Energy Harvesting Wireless Sensor Networks

PubMed Central

Cheng, Wenchi; Zhang, Hailin

2017-01-01

Energy harvesting, which offers a never-ending energy supply, has emerged as a prominent technology to prolong the lifetime and reduce costs for the battery-powered wireless sensor networks. However, how to improve the energy efficiency while guaranteeing the quality of service (QoS) for energy harvesting based wireless sensor networks is still an open problem. In this paper, we develop statistical delay-bounded QoS-driven power control policies to maximize the effective energy efficiency (EEE), which is defined as the spectrum efficiency under given specified QoS constraints per unit harvested energy, for energy harvesting based wireless sensor networks. For the battery-infinite wireless sensor networks, our developed QoS-driven power control policy converges to the Energy harvesting Water Filling (E-WF) scheme and the Energy harvesting Channel Inversion (E-CI) scheme under the very loose and stringent QoS constraints, respectively. For the battery-finite wireless sensor networks, our developed QoS-driven power control policy becomes the Truncated energy harvesting Water Filling (T-WF) scheme and the Truncated energy harvesting Channel Inversion (T-CI) scheme under the very loose and stringent QoS constraints, respectively. Furthermore, we evaluate the outage probabilities to theoretically analyze the performance of our developed QoS-driven power control policies. The obtained numerical results validate our analysis and show that our developed optimal power control policies can optimize the EEE over energy harvesting based wireless sensor networks. PMID:28832509

Statistical-QoS Guaranteed Energy Efficiency Optimization for Energy Harvesting Wireless Sensor Networks.

PubMed

Gao, Ya; Cheng, Wenchi; Zhang, Hailin

2017-08-23

Energy harvesting, which offers a never-ending energy supply, has emerged as a prominent technology to prolong the lifetime and reduce costs for the battery-powered wireless sensor networks. However, how to improve the energy efficiency while guaranteeing the quality of service (QoS) for energy harvesting based wireless sensor networks is still an open problem. In this paper, we develop statistical delay-bounded QoS-driven power control policies to maximize the effective energy efficiency (EEE), which is defined as the spectrum efficiency under given specified QoS constraints per unit harvested energy, for energy harvesting based wireless sensor networks. For the battery-infinite wireless sensor networks, our developed QoS-driven power control policy converges to the Energy harvesting Water Filling (E-WF) scheme and the Energy harvesting Channel Inversion (E-CI) scheme under the very loose and stringent QoS constraints, respectively. For the battery-finite wireless sensor networks, our developed QoS-driven power control policy becomes the Truncated energy harvesting Water Filling (T-WF) scheme and the Truncated energy harvesting Channel Inversion (T-CI) scheme under the very loose and stringent QoS constraints, respectively. Furthermore, we evaluate the outage probabilities to theoretically analyze the performance of our developed QoS-driven power control policies. The obtained numerical results validate our analysis and show that our developed optimal power control policies can optimize the EEE over energy harvesting based wireless sensor networks.

Automated Construction of Node Software Using Attributes in a Ubiquitous Sensor Network Environment

PubMed Central

Lee, Woojin; Kim, Juil; Kang, JangMook

2010-01-01

In sensor networks, nodes must often operate in a demanding environment facing restrictions such as restricted computing resources, unreliable wireless communication and power shortages. Such factors make the development of ubiquitous sensor network (USN) applications challenging. To help developers construct a large amount of node software for sensor network applications easily and rapidly, this paper proposes an approach to the automated construction of node software for USN applications using attributes. In the proposed technique, application construction proceeds by first developing a model for the sensor network and then designing node software by setting the values of the predefined attributes. After that, the sensor network model and the design of node software are verified. The final source codes of the node software are automatically generated from the sensor network model. We illustrate the efficiency of the proposed technique by using a gas/light monitoring application through a case study of a Gas and Light Monitoring System based on the Nano-Qplus operating system. We evaluate the technique using a quantitative metric—the memory size of execution code for node software. Using the proposed approach, developers are able to easily construct sensor network applications and rapidly generate a large number of node softwares at a time in a ubiquitous sensor network environment. PMID:22163678

Automated construction of node software using attributes in a ubiquitous sensor network environment.

PubMed

Lee, Woojin; Kim, Juil; Kang, JangMook

2010-01-01

In sensor networks, nodes must often operate in a demanding environment facing restrictions such as restricted computing resources, unreliable wireless communication and power shortages. Such factors make the development of ubiquitous sensor network (USN) applications challenging. To help developers construct a large amount of node software for sensor network applications easily and rapidly, this paper proposes an approach to the automated construction of node software for USN applications using attributes. In the proposed technique, application construction proceeds by first developing a model for the sensor network and then designing node software by setting the values of the predefined attributes. After that, the sensor network model and the design of node software are verified. The final source codes of the node software are automatically generated from the sensor network model. We illustrate the efficiency of the proposed technique by using a gas/light monitoring application through a case study of a Gas and Light Monitoring System based on the Nano-Qplus operating system. We evaluate the technique using a quantitative metric-the memory size of execution code for node software. Using the proposed approach, developers are able to easily construct sensor network applications and rapidly generate a large number of node softwares at a time in a ubiquitous sensor network environment.

Smart Cruise Control: UAV sensor operator intent estimation and its application

NASA Astrophysics Data System (ADS)

Cheng, Hui; Butler, Darren; Kumar, Rakesh

2006-05-01

Due to their long endurance, superior mobility and the low risk posed to the pilot and sensor operator, UAVs have become the preferred platform for persistent ISR missions. However, currently most UAV based ISR missions are conducted through manual operation. Event the simplest tasks, such as vehicle tracking, route reconnaissance and site monitoring, need the sensor operator's undivided attention and constant adjustment of the sensor control. The lack of autonomous behaviour greatly limits of the effectiveness and the capability of UAV-based ISR, especially the use of a large number of UAVs simultaneously. Although fully autonomous UAV based ISR system is desirable, it is still a distant dream due to the complexity and diversity of combat and ISR missions. In this paper, we propose a Smart Cruise Control system that can learn UAV sensor operator's intent and use it to complete tasks automatically, such as route reconnaissance and site monitoring. Using an operator attention model, the proposed system can estimate the operator's intent from how they control the sensor (e.g. camera) and the content of the imagery that is acquired. Therefore, for example, from initially manually controlling the UAV sensor to follow a road, the system can learn not only the preferred operation, "tracking", but also the road appearance, "what to track" in real-time. Then, the learnt models of both road and the desired operation can be used to complete the task automatically. We have demonstrated the Smart Cruise Control system using real UAV videos where roads need to be tracked and buildings need to be monitored.

Operation tools with dielectric elastomer pressure sensors

NASA Astrophysics Data System (ADS)

Böse, Holger; Müller, Dominik; Ehrlich, Johannes

2017-04-01

New sensors based on dielectric elastomers have recently been shown to exhibit high sensitivity for compression loads. The basic design of these sensors exhibits two profiled surfaces coated with electrode layers between which an elastomer film with the counter-electrode is confined. All components of the sensor are prepared with silicone whose stiffness can be varied in a wide range. Depending on the details of the sensor design, various effects contribute to the enhancement of the capacitance. The intermediate elastomer film is stretched upon compression, the elastomer profiles are deformed and the electrode layers on the elastomer profiles and in the elastomer film approach each other. Beside the detection of pressure, such sensors can also be used for operation tools in human-machine interfaces. To demonstrate this potential, a touch pad with six pressure-sensitive fields is presented. The corresponding sensors integrated in the touch fields detect the exerted forces of the finger, show them on a display and control the brightness of some LEDs. As a second example, the integration of sensor-based control fields on an automotive steering wheel is shown. Finally, the sensors can also be used in fabrics to control arbitrary functions of wearable electronic devices.

Measurement and Control System Based on Wireless Senor Network for Granary

NASA Astrophysics Data System (ADS)

Song, Jian

A wireless measurement and control system for granary is developed for the sake of overcoming the shortcoming of the wired measurement and control system such as complex wiring and low anti-interference capacity. In this system, Zigbee technology is applied with Zigbee protocol stack development platform by TI, and wireless senor network is used to collect and control the temperature and the humidity. It is composed of the upper PC, central control node based on CC2530, sensor nodes, sensor modules and the executive device. The wireless sensor node is programmed by C language in IAR Embedded Workbench for MCS-51 Evaluation environment. The upper PC control system software is developed based on Visual C++ 6.0 platform. It is shown by experiments that data transmission in the system is accurate and reliable and the error of the temperature and humidity is below 2%, meeting the functional requirements for the granary measurement and control system.

Ultra-Precision Measurement and Control of Angle Motion in Piezo-Based Platforms Using Strain Gauge Sensors and a Robust Composite Controller

PubMed Central

Liu, Lei; Bai, Yu-Guang; Zhang, Da-Li; Wu, Zhi-Gang

2013-01-01

The measurement and control strategy of a piezo-based platform by using strain gauge sensors (SGS) and a robust composite controller is investigated in this paper. First, the experimental setup is constructed by using a piezo-based platform, SGS sensors, an AD5435 platform and two voltage amplifiers. Then, the measurement strategy to measure the tip/tilt angles accurately in the order of sub-μrad is presented. A comprehensive composite control strategy design to enhance the tracking accuracy with a novel driving principle is also proposed. Finally, an experiment is presented to validate the measurement and control strategy. The experimental results demonstrate that the proposed measurement and control strategy provides accurate angle motion with a root mean square (RMS) error of 0.21 μrad, which is approximately equal to the noise level. PMID:23860316

Nature inspired capacitive sensor with unique and unclonable characteristic

NASA Astrophysics Data System (ADS)

Karuthedath, C. B.; Schwesinger, N.

2018-02-01

Background of this paper is the development of sensors showing a nature like characteristic. The sensor is able to detect excitations on inertia bases and operates capacitive. It consists of a miniaturized interdigitated electrode structure on a printed circuit board, a flexible and conductive membrane of PDMS located in a certain distance above and a certain number of steel balls fixed on top of the membrane. The steel ball distribution is random and the conductivity of the membrane is not homogeneous across the membrane. Due to this double random distribution, no sensor equals the other, although the external geometry is equal. The overall size of the sensor is 4.7mm x 4.7mm x 1.7mm. Tilt, acceleration or magnetic fields are capable of causing forces on the steel balls and therefore relative movements between the membrane and the electrode structures. Due to this movement, capacity changes of the arrangement are measurable. This paper describes besides the fabrication of conductive membranes the preparation of regarding sensors. Process technology makes cloning of the sensors impossible. Although all process steps are suited for mass production, no sensor equals the other. Measurements with these sensors prove that each sensor reacts differently to the same excitation. Calculations of the Intra-Concordance-Coefficient show the similarity of the sensors for equal excitations. On the other hand, the maximum Inter-Concordance-Coefficient reveals the differences of such sensors very clearly. Such a characteristic, i.e. equal reaction to equal excitation and an output of significantly different signals allows considering each sensor as a unique device. The sensors obviously behave like receptors in natural organisms. These unusual properties of uniqueness and impossibility to clone make the sensors very interesting for highly secure identification demands. In combination with a very simple measurement procedure, the sensors are an attractive hardware base for technical security solutions.

Distributed and Modular CAN-Based Architecture for Hardware Control and Sensor Data Integration

PubMed Central

Losada, Diego P.; Fernández, Joaquín L.; Paz, Enrique; Sanz, Rafael

2017-01-01

In this article, we present a CAN-based (Controller Area Network) distributed system to integrate sensors, actuators and hardware controllers in a mobile robot platform. With this work, we provide a robust, simple, flexible and open system to make hardware elements or subsystems communicate, that can be applied to different robots or mobile platforms. Hardware modules can be connected to or disconnected from the CAN bus while the system is working. It has been tested in our mobile robot Rato, based on a RWI (Real World Interface) mobile platform, to replace the old sensor and motor controllers. It has also been used in the design of two new robots: BellBot and WatchBot. Currently, our hardware integration architecture supports different sensors, actuators and control subsystems, such as motor controllers and inertial measurement units. The integration architecture was tested and compared with other solutions through a performance analysis of relevant parameters such as transmission efficiency and bandwidth usage. The results conclude that the proposed solution implements a lightweight communication protocol for mobile robot applications that avoids transmission delays and overhead. PMID:28467381

Distributed and Modular CAN-Based Architecture for Hardware Control and Sensor Data Integration.

PubMed

Losada, Diego P; Fernández, Joaquín L; Paz, Enrique; Sanz, Rafael

2017-05-03

In this article, we present a CAN-based (Controller Area Network) distributed system to integrate sensors, actuators and hardware controllers in a mobile robot platform. With this work, we provide a robust, simple, flexible and open system to make hardware elements or subsystems communicate, that can be applied to different robots or mobile platforms. Hardware modules can be connected to or disconnected from the CAN bus while the system is working. It has been tested in our mobile robot Rato, based on a RWI (Real World Interface) mobile platform, to replace the old sensor and motor controllers. It has also been used in the design of two new robots: BellBot and WatchBot. Currently, our hardware integration architecture supports different sensors, actuators and control subsystems, such as motor controllers and inertial measurement units. The integration architecture was tested and compared with other solutions through a performance analysis of relevant parameters such as transmission efficiency and bandwidth usage. The results conclude that the proposed solution implements a lightweight communication protocol for mobile robot applications that avoids transmission delays and overhead.

Do job demands and job control affect problem-solving?

PubMed

Bergman, Peter N; Ahlberg, Gunnel; Johansson, Gun; Stoetzer, Ulrich; Aborg, Carl; Hallsten, Lennart; Lundberg, Ingvar

2012-01-01

The Job Demand Control model presents combinations of working conditions that may facilitate learning, the active learning hypothesis, or have detrimental effects on health, the strain hypothesis. To test the active learning hypothesis, this study analysed the effects of job demands and job control on general problem-solving strategies. A population-based sample of 4,636 individuals (55% women, 45% men) with the same job characteristics measured at two times with a three year time lag was used. Main effects of demands, skill discretion, task authority and control, and the combined effects of demands and control were analysed in logistic regressions, on four outcomes representing general problem-solving strategies. Those reporting high on skill discretion, task authority and control, as well as those reporting high demand/high control and low demand/high control job characteristics were more likely to state using problem solving strategies. Results suggest that working conditions including high levels of control may affect how individuals cope with problems and that workplace characteristics may affect behaviour in the non-work domain.

Controlling the COD removal of an A-stage pilot study with instrumentation and automatic process control.

PubMed

Miller, Mark W; Elliott, Matt; DeArmond, Jon; Kinyua, Maureen; Wett, Bernhard; Murthy, Sudhir; Bott, Charles B

2017-06-01

The pursuit of fully autotrophic nitrogen removal via the anaerobic ammonium oxidation (anammox) pathway has led to an increased interest in carbon removal technologies, particularly the A-stage of the adsorption/bio-oxidation (A/B) process. The high-rate operation of the A-stage and lack of automatic process control often results in wide variations of chemical oxygen demand (COD) removal that can ultimately impact nitrogen removal in the downstream B-stage process. This study evaluated the use dissolved oxygen (DO) and mixed liquor suspended solids (MLSS) based automatic control strategies through the use of in situ on-line sensors in the A-stage of an A/B pilot study. The objective of using these control strategies was to reduce the variability of COD removal by the A-stage and thus the variability of the effluent C/N. The use of cascade DO control in the A-stage did not impact COD removal at the conditions tested in this study, likely because the bulk DO concentration (>0.5 mg/L) was maintained above the half saturation coefficient of heterotrophic organisms for DO. MLSS-based solids retention time (SRT) control, where MLSS was used as a surrogate for SRT, did not significantly reduce the effluent C/N variability but it was able to reduce COD removal variation in the A-stage by 90%.

Research and Experiments on a Unipolar Capacitive Voltage Sensor

PubMed Central

Zhou, Qiang; He, Wei; Li, Songnong; Hou, Xingzhe

2015-01-01

Voltage sensors are an important part of the electric system. In service, traditional voltage sensors need to directly contact a high-voltage charged body. Sensors involve a large volume, complex insulation structures, and high design costs. Typically an iron core structure is adopted. As a result, ferromagnetic resonance can occur easily during practical application. Moreover, owing to the multilevel capacitor divider, the sensor cannot reflect the changes of measured voltage in time. Based on the electric field coupling principle, this paper designs a new voltage sensor; the unipolar structure design solves many problems of traditional voltage sensors like the great insulation design difficulty and high costs caused by grounding electrodes. A differential signal input structure is adopted for the detection circuit, which effectively restrains the influence of the common-mode interference signal. Through sensor modeling, simulation and calculations, the structural design of the sensor electrode was optimized, miniaturization of the sensor was realized, the voltage division ratio of the sensor was enhanced, and the phase difference of sensor measurement was weakened. The voltage sensor is applied to a single-phase voltage class line of 10 kV for testing. According to the test results, the designed sensor is able to meet the requirements of accurate and real-time measurement for voltage of the charged conductor as well as to provide a new method for electricity larceny prevention and on-line monitoring of the power grid in an electric system. Therefore, it can satisfy the development demands of the smart power grid. PMID:26307992

Wavefront sensorless adaptive optics ophthalmoscopy in the human eye

PubMed Central

Hofer, Heidi; Sredar, Nripun; Queener, Hope; Li, Chaohong; Porter, Jason

2011-01-01

Wavefront sensor noise and fidelity place a fundamental limit on achievable image quality in current adaptive optics ophthalmoscopes. Additionally, the wavefront sensor ‘beacon’ can interfere with visual experiments. We demonstrate real-time (25 Hz), wavefront sensorless adaptive optics imaging in the living human eye with image quality rivaling that of wavefront sensor based control in the same system. A stochastic parallel gradient descent algorithm directly optimized the mean intensity in retinal image frames acquired with a confocal adaptive optics scanning laser ophthalmoscope (AOSLO). When imaging through natural, undilated pupils, both control methods resulted in comparable mean image intensities. However, when imaging through dilated pupils, image intensity was generally higher following wavefront sensor-based control. Despite the typically reduced intensity, image contrast was higher, on average, with sensorless control. Wavefront sensorless control is a viable option for imaging the living human eye and future refinements of this technique may result in even greater optical gains. PMID:21934779

Energy Harvesting Hybrid Acoustic-Optical Underwater Wireless Sensor Networks Localization.

PubMed

Saeed, Nasir; Celik, Abdulkadir; Al-Naffouri, Tareq Y; Alouini, Mohamed-Slim

2017-12-26

Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs) is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS) based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB) is derived for localization accuracy of the proposed technique.

Energy Harvesting Hybrid Acoustic-Optical Underwater Wireless Sensor Networks Localization

PubMed Central

Saeed, Nasir; Celik, Abdulkadir; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

2017-01-01

Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs) is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS) based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB) is derived for localization accuracy of the proposed technique. PMID:29278405

Integrated optical sensor

DOEpatents

Watkins, Arthur D.; Smartt, Herschel B.; Taylor, Paul L.

1994-01-01

An integrated optical sensor for arc welding having multifunction feedback control. The sensor, comprising generally a CCD camera and diode laser, is positioned behind the arc torch for measuring weld pool position and width, standoff distance, and post-weld centerline cooling rate. Computer process information from this sensor is passed to a controlling computer for use in feedback control loops to aid in the control of the welding process. Weld pool position and width are used in a feedback loop, by the weld controller, to track the weld pool relative to the weld joint. Sensor standoff distance is used in a feedback loop to control the contact tip to base metal distance during the welding process. Cooling rate information is used to determine the final metallurgical state of the weld bead and heat affected zone, thereby controlling post-weld mechanical properties.

Integrated optical sensor

DOEpatents

Watkins, A.D.; Smartt, H.B.; Taylor, P.L.

1994-01-04

An integrated optical sensor for arc welding having multifunction feedback control is described. The sensor, comprising generally a CCD camera and diode laser, is positioned behind the arc torch for measuring weld pool position and width, standoff distance, and post-weld centerline cooling rate. Computer process information from this sensor is passed to a controlling computer for use in feedback control loops to aid in the control of the welding process. Weld pool position and width are used in a feedback loop, by the weld controller, to track the weld pool relative to the weld joint. Sensor standoff distance is used in a feedback loop to control the contact tip to base metal distance during the welding process. Cooling rate information is used to determine the final metallurgical state of the weld bead and heat affected zone, thereby controlling post-weld mechanical properties. 6 figures.

The benefits of soft sensor and multi-rate control for the implementation of Wireless Networked Control Systems.

PubMed

Mansano, Raul K; Godoy, Eduardo P; Porto, Arthur J V

2014-12-18

Recent advances in wireless networking technology and the proliferation of industrial wireless sensors have led to an increasing interest in using wireless networks for closed loop control. The main advantages of Wireless Networked Control Systems (WNCSs) are the reconfigurability, easy commissioning and the possibility of installation in places where cabling is impossible. Despite these advantages, there are two main problems which must be considered for practical implementations of WNCSs. One problem is the sampling period constraint of industrial wireless sensors. This problem is related to the energy cost of the wireless transmission, since the power supply is limited, which precludes the use of these sensors in several closed-loop controls. The other technological concern in WNCS is the energy efficiency of the devices. As the sensors are powered by batteries, the lowest possible consumption is required to extend battery lifetime. As a result, there is a compromise between the sensor sampling period, the sensor battery lifetime and the required control performance for the WNCS. This paper develops a model-based soft sensor to overcome these problems and enable practical implementations of WNCSs. The goal of the soft sensor is generating virtual data allowing an actuation on the process faster than the maximum sampling period available for the wireless sensor. Experimental results have shown the soft sensor is a solution to the sampling period constraint problem of wireless sensors in control applications, enabling the application of industrial wireless sensors in WNCSs. Additionally, our results demonstrated the soft sensor potential for implementing energy efficient WNCS through the battery saving of industrial wireless sensors.

Printed organo-functionalized graphene for biosensing applications.

PubMed

Wisitsoraat, A; Mensing, J Ph; Karuwan, C; Sriprachuabwong, C; Jaruwongrungsee, K; Phokharatkul, D; Daniels, T M; Liewhiran, C; Tuantranont, A

2017-01-15

Graphene is a highly promising material for biosensors due to its excellent physical and chemical properties which facilitate electron transfer between the active locales of enzymes or other biomaterials and a transducer surface. Printing technology has recently emerged as a low-cost and practical method for fabrication of flexible and disposable electronics devices. The combination of these technologies is promising for the production and commercialization of low cost sensors. In this review, recent developments in organo-functionalized graphene and printed biosensor technologies are comprehensively covered. Firstly, various methods for printing graphene-based fluids on different substrates are discussed. Secondly, different graphene-based ink materials and preparation methods are described. Lastly, biosensing performances of printed or printable graphene-based electrochemical and field effect transistor sensors for some important analytes are elaborated. The reported printed graphene based sensors exhibit promising properties with good reliability suitable for commercial applications. Among most reports, only a few printed graphene-based biosensors including screen-printed oxidase-functionalized graphene biosensor have been demonstrated. The technology is still at early stage but rapidly growing and will earn great attention in the near future due to increasing demand of low-cost and disposable biosensors. Copyright © 2016 Elsevier B.V. All rights reserved.

Blood pulse wave velocity and pressure sensing via fiber based and free space based optical sensors

NASA Astrophysics Data System (ADS)

Sirkis, Talia; Beiderman, Yevgeny; Agdarov, Sergey; Beiderman, Yafim; Zalevsky, Zeev

2017-02-01

Continuous noninvasive measurement of vital bio-signs, such as cardiopulmonary parameters, is an important tool in evaluation of the patient's physiological condition and health monitoring. On the demand of new enabling technologies, some works have been done in continuous monitoring of blood pressure and pulse wave velocity. In this paper, we introduce two techniques for non-contact sensing of vital bio signs. In the first approach the optical sensor is based on single mode in-fibers Mach-Zehnder interferometer (MZI) to detect heartbeat, respiration and pulse wave velocity (PWV). The introduced interferometer is based on a new implanted scheme. It replaces the conventional MZI realized by inserting of discontinuities in the fiber to break the total internal reflection and scatter/collect light. The proposed fiber sensor was successfully incorporated into shirt to produce smart clothing. The measurements obtained from the smart clothing could be obtained in comfortable manner and there is no need to have an initial calibration or a direct contact between the sensor and the skin of the tested individual. In the second concept we show a remote noncontact blood pulse wave velocity and pressure measurement based on tracking the temporal changes of reflected secondary speckle patterns produced in human skin when illuminated by a laser beams. In both concept experimental validation of the proposed schemes is shown and analyzed.

A new torsion pendulum for testing enhancements to the LISA Gravitational Reference Sensor

NASA Astrophysics Data System (ADS)

Conklin, John; Chilton, A.; Ciani, G.; Mueller, G.; Olatunde, T.; Shelley, R.

2014-01-01

The Laser Interferometer Space Antenna (LISA), the most mature concept for observing gravitational waves from space, consists of three Sun-orbiting spacecraft that form a million km-scale equilateral triangle. Each spacecraft houses two free-floating test masses (TM), which are protected from disturbing forces so that they follow pure geodesics in spacetime. A single test mass together with its housing and associated components is referred to as a gravitational reference sensor (GRS). Laser interferometry is used to measure the minute variations in the distance between these free-falling TMs, caused by gravitational waves. The demanding acceleration noise requirement of 3E-15 m/sec^2Hz^1/2 for the LISA GRS has motivated a rigorous testing campaign in Europe and a dedicated technology mission, LISA Pathfinder, scheduled for launch in 2015. Recently, efforts have begun in the U.S. to design and assemble a new, nearly thermally noise limited torsion pendulum for testing GRS technology enhancements and for understanding the dozens of acceleration noise sources that affect the performance of the GRS. This experimental facility is based on the design of a similar facility at the University of Trento, and will consist of a vacuum enclosed torsion pendulum that suspends mock-ups of the LISA test masses, surrounded by electrode housings. The GRS technology enhancements under development include a novel TM charge control scheme based on ultraviolet LEDs, simplified capacitive readout electronics, and a six degree-of-freedom, all-optical TM sensor. This presentation will describe the design of the torsion pendulum facility, its expected performance, and the potential technology enhancements.

High-performance multi-channel fiber-based absolute distance measuring interferometer system

NASA Astrophysics Data System (ADS)

Deck, Leslie L.

2009-08-01

I describe the principle of operation and performance of a fiber-based absolute distance measuring interferometer system with 60 independent simultaneous channels. The system was designed for demanding applications requiring passive, electrically immune sensors with an extremely long MTTF. In addition to providing better than 0.3nm measurement repeatability at 5KHz for all channels, the system demonstrated absolute distance uncertainty of less than 5nm over a 500 micron measurement range.

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. This study is the first to use wearable sensors in unsupervised activities of daily living in combination with novel machine learning algorithms to investigate the aerobic system dynamics with the potential to contribute to models of functional health status and guide future individualized health care in the normal population.

Method for Reading Sensors and Controlling Actuators Using Audio Interfaces of Mobile Devices

PubMed Central

Aroca, Rafael V.; Burlamaqui, Aquiles F.; Gonçalves, Luiz M. G.

2012-01-01

This article presents a novel closed loop control architecture based on audio channels of several types of computing devices, such as mobile phones and tablet computers, but not restricted to them. The communication is based on an audio interface that relies on the exchange of audio tones, allowing sensors to be read and actuators to be controlled. As an application example, the presented technique is used to build a low cost mobile robot, but the system can also be used in a variety of mechatronics applications and sensor networks, where smartphones are the basic building blocks. PMID:22438726

Method for reading sensors and controlling actuators using audio interfaces of mobile devices.

PubMed

Aroca, Rafael V; Burlamaqui, Aquiles F; Gonçalves, Luiz M G

2012-01-01

This article presents a novel closed loop control architecture based on audio channels of several types of computing devices, such as mobile phones and tablet computers, but not restricted to them. The communication is based on an audio interface that relies on the exchange of audio tones, allowing sensors to be read and actuators to be controlled. As an application example, the presented technique is used to build a low cost mobile robot, but the system can also be used in a variety of mechatronics applications and sensor networks, where smartphones are the basic building blocks.

Contact position sensor using constant contact force control system

NASA Technical Reports Server (NTRS)

Sturdevant, Jay (Inventor)

1995-01-01

A force control system (50) and method are provided for controlling a position contact sensor (10) so as to produce a constant controlled contact force therewith. The system (50) includes a contact position sensor (10) which has a contact probe (12) for contacting the surface of a target to be measured and an output signal (V.sub.o) for providing a position indication thereof. An actuator (30) is provided for controllably driving the contact position sensor (10) in response to an actuation control signal (I). A controller (52) receives the position indication signal (V.sub.o) and generates in response thereto the actuation control signal (I) so as to provide a substantially constant selective force (F) exerted by the contact probe (12). The actuation drive signal (I) is generated further in response to substantially linear approximation curves based on predetermined force and position data attained from the sensor (10) and the actuator (30).

Electrically controlled drug release from nanostructured polypyrrole coated on titanium

NASA Astrophysics Data System (ADS)

Sirivisoot, Sirinrath; Pareta, Rajesh; Webster, Thomas J.

2011-02-01

Previous studies have demonstrated that multi-walled carbon nanotubes grown out of anodized nanotubular titanium (MWNT-Ti) can be used as a sensing electrode for various biomedical applications; such sensors detected the redox reactions of certain molecules, specifically proteins deposited by osteoblasts during extracellular matrix bone formation. Since it is known that polypyrrole (PPy) can release drugs upon electrical stimulation, in this study antibiotics (penicillin/streptomycin, P/S) or an anti-inflammatory drug (dexamethasone, Dex), termed PPy[P/S] or PPy[Dex], respectively, were electrodeposited in PPy on titanium. The objective of the present study was to determine if such drugs can be released from PPy on demand and (by applying a voltage) control cellular behavior important for orthopedic applications. Results showed that PPy films possessed nanometer-scale roughness as analyzed by atomic force microscopy. X-ray photoelectron spectroscopy confirmed the presence of P/S and Dex encapsulated within the PPy films. Results from cyclic voltammetry showed that 80% of the drugs were released on demand when sweep voltages were applied for five cycles at a scan rate of 0.1 V s - 1. Furthermore, osteoblast (bone-forming cells) and fibroblast (fibrous tissue-forming cells) adhesion were determined on the PPy films. Results showed that PPy[Dex] enhanced osteoblast adhesion after 4 h of culture compared to plain Ti. PPy-Ti (with or without anionic drug doping) inhibited fibroblast adhesion compared to plain Ti. These in vitro results confirmed that electrodeposited PPy[P/S] and PPy[Dex] can release drugs on demand to potentially fight bacterial infection, reduce inflammation, promote bone growth or reduce fibroblast functions, further implicating the use of such materials as implant sensors.

End-User Tools Towards AN Efficient Electricity Consumption: the Dynamic Smart Grid

NASA Astrophysics Data System (ADS)

Kamel, Fouad; Kist, Alexander A.

2010-06-01

Growing uncontrolled electrical demands have caused increased supply requirements. This causes volatile electrical markets and has detrimental unsustainable environmental impacts. The market is presently characterized by regular daily peak demand conditions associated with high electricity prices. A demand-side response system can limit peak demands to an acceptable level. The proposed scheme is based on energy demand and price information which is available online. An online server is used to communicate the information of electricity suppliers to users, who are able to use the information to manage and control their own demand. A configurable, intelligent switching system is used to control local loads during peak events and mange the loads at other times as necessary. The aim is to shift end user loads towards periods where energy demand and therefore also prices are at the lowest. As a result, this will flatten the load profile and avoiding load peeks which are costly for suppliers. The scheme is an endeavour towards achieving a dynamic smart grid demand-side-response environment using information-based communication and computer-controlled switching. Diffusing the scheme shall lead to improved electrical supply services and controlled energy consumption and prices.

LoRa Mobile-To-Base-Station Channel Characterization in the Antarctic.

PubMed

Gaelens, Johnny; Van Torre, Patrick; Verhaevert, Jo; Rogier, Hendrik

2017-08-18

Antarctic conditions demand that wireless sensor nodes are operational all year round and that they provide a large communication range of several tens of kilometers. LoRa technology operating in sub-GHz frequency bands implements these wireless links with minimal power consumption. The employed chirp spread spectrum modulation provides a large link budget, combined with the excellent radio-wave propagation characteristics in these bands. In this paper, an experimental wireless link from a mobile vehicle which transmits sensor data to a base station is measured and analyzed in terms of signal-to-noise ratio and packet loss. These measurements confirm the usefulness of LoRa technology for wireless sensor systems in polar regions. By deploying directional antennas at the base station, a range of up to 30 km is covered in case of Line-of-Sight radio propagation in both the 434 and 868 MHz bands. Varying terrain elevation is shown to be the dominating factor influencing the propagation, sometimes causing the Line-of-Sight path to be obstructed. Tropospheric radio propagation effects were not apparent in the measurements.

LoRa Mobile-To-Base-Station Channel Characterization in the Antarctic

PubMed Central

Gaelens, Johnny; Van Torre, Patrick; Verhaevert, Jo

2017-01-01

Antarctic conditions demand that wireless sensor nodes are operational all year round and that they provide a large communication range of several tens of kilometers. LoRa technology operating in sub-GHz frequency bands implements these wireless links with minimal power consumption. The employed chirp spread spectrum modulation provides a large link budget, combined with the excellent radio-wave propagation characteristics in these bands. In this paper, an experimental wireless link from a mobile vehicle which transmits sensor data to a base station is measured and analyzed in terms of signal-to-noise ratio and packet loss. These measurements confirm the usefulness of LoRa technology for wireless sensor systems in polar regions. By deploying directional antennas at the base station, a range of up to 30 km is covered in case of Line-of-Sight radio propagation in both the 434 and 868 MHz bands. Varying terrain elevation is shown to be the dominating factor influencing the propagation, sometimes causing the Line-of-Sight path to be obstructed. Tropospheric radio propagation effects were not apparent in the measurements. PMID:28820477

Design of a Water Environment Monitoring System Based on Wireless Sensor Networks

PubMed Central

Jiang, Peng; Xia, Hongbo; He, Zhiye; Wang, Zheming

2009-01-01

A water environmental monitoring system based on a wireless sensor network is proposed. It consists of three parts: data monitoring nodes, data base station and remote monitoring center. This system is suitable for the complex and large-scale water environment monitoring, such as for reservoirs, lakes, rivers, swamps, and shallow or deep groundwaters. This paper is devoted to the explanation and illustration for our new water environment monitoring system design. The system had successfully accomplished the online auto-monitoring of the water temperature and pH value environment of an artificial lake. The system's measurement capacity ranges from 0 to 80 °C for water temperature, with an accuracy of ±0.5 °C; from 0 to 14 on pH value, with an accuracy of ±0.05 pH units. Sensors applicable to different water quality scenarios should be installed at the nodes to meet the monitoring demands for a variety of water environments and to obtain different parameters. The monitoring system thus promises broad applicability prospects. PMID:22454592

Non-electrical-power temperature-time integrating sensor for RFID based on microfluidics

NASA Astrophysics Data System (ADS)

Schneider, Mike; Hoffmann, Martin

2011-06-01

The integration of RFID tags into packages offers the opportunity to combine logistic advantages of the technology with monitoring different parameters from inside the package at the same time. An essential demand for enhanced product safety especially in pharmacy or food industry is the monitoring of the time-temperature-integral. Thus, completely passive time-temperature-integrators (TTI) requiring no battery, microprocessor nor data logging devices are developed. TTI representing the sterilization process inside an autoclave system is a demanding challenge: a temperature of at least 120 °C have to be maintained over 45 minutes to assure that no unwanted organism remains. Due to increased temperature, the viscosity of a fluid changes and thus the speed of the fluid inside the channel increases. The filled length of the channel represents the time temperature integral affecting the system. Measurements as well as simulations allow drawing conclusions about the influence of the geometrical parameters of the system and provide the possibility of adaptation. Thus a completely passive sensor element for monitoring an integral parameter with waiving of external electrical power supply and data processing technology is demonstrated. Furthermore, it is shown how to adjust the specific TTI parameters of the sensor to different applications and needs by modifying the geometrical parameters of the system.

Harsh environment sensor development for advanced energy systems

NASA Astrophysics Data System (ADS)

Romanosky, Robert R.; Maley, Susan M.

2013-05-01

Highly efficient, low emission power systems have extreme conditions of high temperature, high pressure, and corrosivity that require monitoring. Sensing in these harsh environments can provide key information that directly impacts process control and system reliability. To achieve the goals and demands of clean energy, the conditions under which fossil fuels are converted into heat and power are harsh compared to traditional combustion/steam cycles. Temperatures can extend as high as 1600 Celsius (°C) in certain systems and pressures can reach as high as 5000 pounds per square inch (psi)/340 atmospheres (atm). The lack of suitable measurement technology serves as a driver for the innovations in harsh environment sensor development. Two major considerations in the development of harsh environments sensors are the materials used for sensing and the design of the sensing device. This paper will highlight the U.S. Department of Energy's, Office of Fossil Energy and National Energy Technology Laboratory's Program in advanced sensing concepts that are aimed at addressing the technology needs and drivers through the development of new sensor materials and designs capable of withstanding harsh environment conditions. Recent developments with harsh environment sensors will be highlighted and future directions towards in advanced sensing will be introduced.

NASA Programs in Advanced Sensors and Measurement Technology for Aeronautical Applications

NASA Technical Reports Server (NTRS)

Conway, Bruce A.

2004-01-01

There are many challenges facing designers and operators of our next-generation aircraft in meeting the demands for efficiency, safety, and reliability which are will be imposed. This paper discusses aeronautical sensor requirements for a number of research and applications areas pertinent to the demands listed above. A brief overview will be given of aeronautical research measurements, along with a discussion of requirements for advanced technology. Also included will be descriptions of emerging sensors and instrumentation technology which may be exploited for enhanced research and operational capabilities. Finally, renewed emphasis of the National Aeronautics and Space Administration in advanced sensor and instrumentation technology development will be discussed, including project of technology advances over the next 5 years. Emphasis on NASA efforts to more actively advance the state-of-the-art in sensors and measurement techniques is timely in light of exciting new opportunities in airspace development and operation. An up-to-date summary of the measurement technology programs being established to respond to these opportunities is provided.

The Development of Metal Oxide Chemical Sensing Nanostructures

NASA Technical Reports Server (NTRS)

Hunter, G. W.; VanderWal,R. L.; Xu, J. C.; Evans, L. J.; Berger, G. M.; Kulis, M. J.

2008-01-01

This paper discusses sensor development based on metal oxide nanostructures and microsystems technology. While nanostructures such as nanowires show significant potential as enabling materials for chemical sensors, a number of significant technical challenges remain. This paper discusses development to address each of these technical barriers: 1) Improved contact and integration of the nanostructured materials with microsystems in a sensor structure; 2) Control of nanostructure crystallinity to allow control of the detection mechanism; and 3) Widening the range of gases that can be detected by fabricating multiple nanostructured materials. A sensor structure composed of three nanostructured oxides aligned on a single microsensor has been fabricated and tested. Results of this testing are discussed and future development approaches are suggested. It is concluded that while this work lays the foundation for further development, these are the beginning steps towards realization of repeatable, controlled sensor systems using oxide based nanostructures.

Architecture for distributed actuation and sensing using smart piezoelectric elements

NASA Astrophysics Data System (ADS)

Etienne-Cummings, Ralph; Pourboghrat, Farzad; Maruboyina, Hari K.; Abrate, Serge; Dhali, Shirshak K.

1998-07-01

We discuss vibration control of a cantilevered plate with multiple sensors and actuators. An architecture is chosen to minimize the number of control and sensing wires required. A custom VLSI chip, integrated with the sensor/actuator elements, controls the local behavior of the plate. All the actuators are addressed in parallel; local decode logic selects which actuator is stimulated. Downloaded binary data controls the applied voltage and modulation frequency for each actuator, and High Voltage MOSFETs are used to activate them. The sensors, which are independent adjacent piezoelectric ceramic elements, can be accessed in a random or sequential manner. An A/D card and GPIB interconnected test equipment allow a PC to read the sensors' outputs and dictate the actuation procedure. A visual programming environment is used to integrate the sensors, controller and actuators. Based on the constitutive relations for the piezoelectric material, simple models for the sensors and actuators are derived. A two level hierarchical robust controller is derived for motion control and for damping of vibrations.

Integrated control of landscape irrigation and rainwater harvesting for urban water management

NASA Astrophysics Data System (ADS)

Lee, J. H.; Dhakal, B.; Noh, S.; Seo, D. J.

2016-12-01

Demand for freshwater is increasing rapidly in large and fast-growing urban areas such as the Dallas-Fort Worth Metroplex (DFW). With almost complete reliance on surface water, water supply for DFW is limited by the available storage in the reservoir systems which is now subject to larger variability due to climate change. Landscape irrigation is estimated to account for nearly one-third of all residential water use in the US and as much as 60% in dry climate areas. In landscape irrigation, a large portion of freshwater is commonly lost by sub-optimal practices. If practiced over a large area, one may expect optimized smart irrigation to significantly reduce urban freshwater demand. For increasing on-site water supply, rainwater harvesting (RHW) is particularly attractive in that it conserves potable water while reducing stormwater runoff. Traditional static RWH methods, however, have limited success due to the inefficient water usage. If, on the other hand, lawn irrigation and rainwater harvesting can be optimized as an integrated operation and controlled adaptively to the feedback from the environmental sensors, weather conditions and forecast, one may expect the combined benefits for water conservation and stormwater management to be larger. In this work, we develop a prototype system for integrated control of lawn irrigation and RWH for water conservation and stormwater management, and assess and demonstrate the potential impact and value of the system. For in-situ evaluation, we deploy a wireless sensor network consisting of low-cost off-the-shelf sensors and open-sourced components, and collect observations of temperature, humidity, soil moisture, and solar radiation at the test site at the UTA community garden in Arlington, Texas. We assess the health of the lawn grass using normalized vegetation index (NDVI) from the time lapse images at the site. In this poster, we describe the approach and share the initial results.

Development of zirconia based phosphors for application in lighting and as luminescent bioprobes =

NASA Astrophysics Data System (ADS)

Soares, Maria Rosa Nunes

The strong progress evidenced in photonic and optoelectronic areas, accompanied by an exponential development in the nanoscience and nanotechnology, gave rise to an increasing demand for efficient luminescent materials with more and more exigent characteristics. In this field, wide band gap hosts doped with lanthanide ions represent a class of luminescent materials with a strong technological importance. Within wide band gap material, zirconia owns a combination of physical and chemical properties that potentiate it as an excellent host for the aforementioned ions, envisaging its use in different areas, including in lighting and optical sensors applications, such as pressure sensors and biosensors. Following the demand for outstanding luminescent materials, there is also a request for fast, economic and an easy scale-up process for their production. Regarding these demands, laser floating zone, solution combustion synthesis and pulsed laser ablation in liquid techniques are explored in this thesis for the production of single crystals, nanopowders and nanoparticles of lanthanides doped zirconia based hosts. Simultaneously, a detailed study of the morphological, structural and optical properties of the produced materials is made. The luminescent characteristics of zirconia and yttria stabilized zirconia (YSZ) doped with different lanthanide ions (Ce3+ (4f1), Pr3+ (4f2), Sm3+ (4f5), Eu3+ (4f6), Tb3+ (4f8), Dy3+ (4f9), Er3+ (4f11), Tm3+ (4f12), Yb3+ (4f13)) and co-doped with Er3+,Yb3+ and Tm3+,Yb3+ are analysed. Besides the Stokes luminescence, the anti- Stokes emission upon infrared excitation (upconversion and black body radiation) is also analysed and discussed. The comparison of the luminescence characteristics in materials with different dimensions allowed to analyse the effect of size in the luminescent properties of the dopant lanthanide ions. The potentialities of application of the produced luminescent materials in solid state light, biosensors and pressure sensors are explored taking into account their studied characteristics.

The relationships among nurses' job characteristics and attitudes toward web-based continuing learning.

PubMed

Chiu, Yen-Lin; Tsai, Chin-Chung; Fan Chiang, Chih-Yun

2013-04-01

The purpose of this study was to explore the relationships between job characteristics (job demands, job control and social support) and nurses' attitudes toward web-based continuing learning. A total of 221 in-service nurses from hospitals in Taiwan were surveyed. The Attitudes toward Web-based Continuing Learning Survey (AWCL) was employed as the outcome variables, and the Chinese version Job Characteristic Questionnaire (C-JCQ) was administered to assess the predictors for explaining the nurses' attitudes toward web-based continuing learning. To examine the relationships among these variables, hierarchical regression was conducted. The results of the regression analysis revealed that job control and social support positively associated with nurses' attitudes toward web-based continuing learning. However, the relationship of job demands to such learning was not significant. Moreover, a significant demands×job control interaction was found, but the job demands×social support interaction had no significant relationships with attitudes toward web-based continuing learning. Copyright © 2013 Elsevier Ltd. All rights reserved.

Web-based remote sensing of building energy performance

NASA Astrophysics Data System (ADS)

Martin, William; Nassiopoulos, Alexandre; Le Cam, Vincent; Kuate, Raphaël; Bourquin, Frédéric

2013-04-01

The present paper describes the design and the deployment of an instrumentation system enabling the energy monitoring of a building in a smart-grid context. The system is based on a network of wireless low power IPv6 sensors. Ambient temperature and electrical power for heating are measured. The management, storage, visualisation and treatment of the data is done through a web-based application that can be deployed as an online web service. The same web-based framework enables the acquisition of distant measured data such as those coming from a nearby weather station. On-site sensor and weather station data are then adequately treated based on inverse identification methods. The algorithms aim at determining the parameters of a numerical model suitable for a short-time horizon prediction of indoor climate. The model is based on standard multi-zone modelling assumptions and takes into account solar, airflow and conductive transfers. It was specially designed to render accurately inertia effects that are used in a demand-response strategy. All the hardware or software technologies that are used in the system are open and low cost so that they comply with the constraints of on-site deployment in buildings. The measured data as well as the model predictions can be accessed ubiquously through the web. This feature enables to consider a wide range of energy management applications at the disctrict, city or national level. The entire system has been deployed and tested in an experimental office building in Angers, France. It demonstrates the potential of ICT technologies to enable remotely controlled monitoring and surveillance in real time.

An interactive control algorithm used for equilateral triangle formation with robotic sensors.

PubMed

Li, Xiang; Chen, Hongcai

2014-04-22

This paper describes an interactive control algorithm, called Triangle Formation Algorithm (TFA), used for three neighboring robotic sensors which are distributed randomly to self-organize into and equilateral triangle (E) formation. The algorithm is proposed based on the triangular geometry and considering the actual sensors used in robotics. In particular, the stability of the TFA, which can be executed by robotic sensors independently and asynchronously for E formation, is analyzed in details based on Lyapunov stability theory. Computer simulations are carried out for verifying the effectiveness of the TFA. The analytical results and simulation studies indicate that three neighboring robots employing conventional sensors can self-organize into E formations successfully regardless of their initial distribution using the same TFAs.

An Interactive Control Algorithm Used for Equilateral Triangle Formation with Robotic Sensors

PubMed Central

Li, Xiang; Chen, Hongcai

2014-01-01

This paper describes an interactive control algorithm, called Triangle Formation Algorithm (TFA), used for three neighboring robotic sensors which are distributed randomly to self-organize into and equilateral triangle (E) formation. The algorithm is proposed based on the triangular geometry and considering the actual sensors used in robotics. In particular, the stability of the TFA, which can be executed by robotic sensors independently and asynchronously for E formation, is analyzed in details based on Lyapunov stability theory. Computer simulations are carried out for verifying the effectiveness of the TFA. The analytical results and simulation studies indicate that three neighboring robots employing conventional sensors can self-organize into E formations successfully regardless of their initial distribution using the same TFAs. PMID:24759118

Dynamic Feed Control For Injection Molding

DOEpatents

Kazmer, David O.

1996-09-17

The invention provides methods and apparatus in which mold material flows through a gate into a mold cavity that defines the shape of a desired part. An adjustable valve is provided that is operable to change dynamically the effective size of the gate to control the flow of mold material through the gate. The valve is adjustable while the mold material is flowing through the gate into the mold cavity. A sensor is provided for sensing a process condition while the part is being molded. During molding, the valve is adjusted based at least in part on information from the sensor. In the preferred embodiment, the adjustable valve is controlled by a digital computer, which includes circuitry for acquiring data from the sensor, processing circuitry for computing a desired position of the valve based on the data from the sensor and a control data file containing target process conditions, and control circuitry for generating signals to control a valve driver to adjust the position of the valve. More complex embodiments include a plurality of gates, sensors, and controllable valves. Each valve is individually controllable so that process conditions corresponding to each gate can be adjusted independently. This allows for great flexibility in the control of injection molding to produce complex, high-quality parts.

Force/torque and tactile sensors for sensor-based manipulator control

NASA Technical Reports Server (NTRS)

Vanbrussel, H.; Belieen, H.; Bao, Chao-Ying

1989-01-01

The autonomy of manipulators, in space and in industrial environments, can be dramatically enhanced by the use of force/torque and tactile sensors. The development and future use of a six-component force/torque sensor for the Hermes Robot Arm (HERA) Basic End-Effector (BEE) is discussed. Then a multifunctional gripper system based on tactile sensors is described. The basic transducing element of the sensor is a sheet of pressure-sensitive polymer. Tactile image processing algorithms for slip detection, object position estimation, and object recognition are described.

Characterization of Industrial Coolant Fluids and Continuous Ageing Monitoring by Wireless Node-Enabled Fiber Optic Sensors.

PubMed

Sachat, Alexandros El; Meristoudi, Anastasia; Markos, Christos; Sakellariou, Andreas; Papadopoulos, Aggelos; Katsikas, Serafim; Riziotis, Christos

2017-03-11

Environmentally robust chemical sensors for monitoring industrial processes or infrastructures are lately becoming important devices in industry. Low complexity and wireless enabled characteristics can offer the required flexibility for sensor deployment in adaptable sensing networks for continuous monitoring and management of industrial assets. Here are presented the design, development and operation of a class of low cost photonic sensors for monitoring the ageing process and the operational characteristics of coolant fluids used in an industrial heavy machinery infrastructure. The chemical, physical and spectroscopic characteristics of specific industrial-grade coolant fluids were analyzed along their entire life cycle range, and proper parameters for their efficient monitoring were identified. Based on multimode polymer or silica optical fibers, wide range (3-11) pH sensors were developed by employing sol-gel derived pH sensitive coatings. The performances of the developed sensors were characterized and compared, towards their coolants' ageing monitoring capability, proving their efficiency in such a demanding application scenario and harsh industrial environment. The operating characteristics of this type of sensors allowed their integration in an autonomous wireless sensing node, thus enabling the future use of the demonstrated platform in wireless sensor networks for a variety of industrial and environmental monitoring applications.

Characterization of Industrial Coolant Fluids and Continuous Ageing Monitoring by Wireless Node—Enabled Fiber Optic Sensors

PubMed Central

El Sachat, Alexandros; Meristoudi, Anastasia; Markos, Christos; Sakellariou, Andreas; Papadopoulos, Aggelos; Katsikas, Serafim; Riziotis, Christos

2017-01-01

Environmentally robust chemical sensors for monitoring industrial processes or infrastructures are lately becoming important devices in industry. Low complexity and wireless enabled characteristics can offer the required flexibility for sensor deployment in adaptable sensing networks for continuous monitoring and management of industrial assets. Here are presented the design, development and operation of a class of low cost photonic sensors for monitoring the ageing process and the operational characteristics of coolant fluids used in an industrial heavy machinery infrastructure. The chemical, physical and spectroscopic characteristics of specific industrial-grade coolant fluids were analyzed along their entire life cycle range, and proper parameters for their efficient monitoring were identified. Based on multimode polymer or silica optical fibers, wide range (3–11) pH sensors were developed by employing sol-gel derived pH sensitive coatings. The performances of the developed sensors were characterized and compared, towards their coolants’ ageing monitoring capability, proving their efficiency in such a demanding application scenario and harsh industrial environment. The operating characteristics of this type of sensors allowed their integration in an autonomous wireless sensing node, thus enabling the future use of the demonstrated platform in wireless sensor networks for a variety of industrial and environmental monitoring applications. PMID:28287488

Novel eye-safe line scanning 3D laser-radar

NASA Astrophysics Data System (ADS)

Eberle, B.; Kern, Tobias; Hammer, Marcus; Schwanke, Ullrich; Nowak, Heinrich

2014-10-01

Today, the civil market provides quite a number of different 3D-Sensors covering ranges up to 1 km. Typically these sensors are based on single element detectors which suffer from the drawback of spatial resolution at larger distances. Tasks demanding reliable object classification at long ranges can be fulfilled only by sensors consisting of detector arrays. They ensure sufficient frame rates and high spatial resolution. Worldwide there are many efforts in developing 3D-detectors, based on two-dimensional arrays. This paper presents first results on the performance of a recently developed 3D imaging laser radar sensor, working in the short wave infrared (SWIR) at 1.5 μm. It consists of a novel Cadmium Mercury Telluride (CMT) linear array APD detector with 384x1 elements at a pitch of 25 μm, developed by AIM Infrarot Module GmbH. The APD elements are designed to work in the linear (non-Geiger) mode. Each pixel will provide the time of flight measurement, and, due to the linear detection mode, allowing the detection of three successive echoes. The resolution in depth is 15 cm, the maximum repetition rate is 4 kHz. We discuss various sensor concepts regarding possible applications and their dependence on system parameters like field of view, frame rate, spatial resolution and range of operation.

Biocompatible enzymatic roller pens for direct writing of biocatalytic materials: "do-it-yourself" electrochemical biosensors.

PubMed

Bandodkar, Amay J; Jia, Wenzhao; Ramírez, Julian; Wang, Joseph

2015-06-03

The development of enzymatic-ink-based roller pens for direct drawing of biocatalytic sensors, in general, and for realizing renewable glucose sensor strips, in particular, is described. The resulting enzymatic-ink pen allows facile fabrication of high-quality inexpensive electrochemical biosensors of any design by the user on a wide variety of surfaces having complex textures with minimal user training. Unlike prefabricated sensors, this approach empowers the end user with the ability of "on-demand" and "on-site" designing and fabricating of biocatalytic sensors to suit their specific requirement. The resulting devices are thus referred to as "do-it-yourself" sensors. The bio-active pens produce highly reproducible biocatalytic traces with minimal edge roughness. The composition of the new enzymatic inks has been optimized for ensuring good biocatalytic activity, electrical conductivity, biocompati-bility, reproducible writing, and surface adherence. The resulting inks are characterized using spectroscopic, viscometric, electrochemical, thermal and microscopic techniques. Applicability to renewable blood glucose testing, epidermal glucose monitoring, and on-leaf phenol detection are demonstrated in connection to glucose oxidase and tyrosinase-based carbon inks. The "do-it-yourself" renewable glucose sensor strips offer a "fresh," reproducible, low-cost biocatalytic sensor surface for each blood test. The ability to directly draw biocatalytic conducting traces even on unconventional surfaces opens up new avenues in various sensing applications in low-resource settings and holds great promise for diverse healthcare, environmental, and defense domains. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DNA as Sensors and Imaging Agents for Metal Ions

PubMed Central

Xiang, Yu

2014-01-01

Increasing interests in detecting metal ions in many chemical and biomedical fields have created demands for developing sensors and imaging agents for metal ions with high sensitivity and selectivity. This review covers recent progress in DNA-based sensors and imaging agents for metal ions. Through both combinatorial selection and rational design, a number of metal ion-dependent DNAzymes and metal ion-binding DNA structures that can selectively recognize specific metal ions have been obtained. By attaching these DNA molecules with signal reporters such as fluorophores, chromophores, electrochemical tags, and Raman tags, a number of DNA-based sensors for both diamagnetic and paramagnetic metal ions have been developed for fluorescent, colorimetric, electrochemical, and surface Raman detections. These sensors are highly sensitive (with detection limit down to 11 ppt) and selective (with selectivity up to millions-fold) toward specific metal ions. In addition, through further development to simplify the operation, such as the use of “dipstick tests”, portable fluorometers, computer-readable discs, and widely available glucose meters, these sensors have been applied for on-site and real-time environmental monitoring and point-of-care medical diagnostics. The use of these sensors for in situ cellular imaging has also been reported. The generality of the combinatorial selection to obtain DNAzymes for almost any metal ion in any oxidation state, and the ease of modification of the DNA with different signal reporters make DNA an emerging and promising class of molecules for metal ion sensing and imaging in many fields of applications. PMID:24359450

Enhanced Sensitivity of Gas Sensor Based on Poly(3-hexylthiophene) Thin-Film Transistors for Disease Diagnosis and Environment Monitoring

PubMed Central

Cavallari, Marco R.; Izquierdo, José E. E.; Braga, Guilherme S.; Dirani, Ely A. T.; Pereira-da-Silva, Marcelo A.; Rodríguez, Estrella F. G.; Fonseca, Fernando J.

2015-01-01

Electronic devices based on organic thin-film transistors (OTFT) have the potential to supply the demand for portable and low-cost gadgets, mainly as sensors for in situ disease diagnosis and environment monitoring. For that reason, poly(3-hexylthiophene) (P3HT) as the active layer in the widely-used bottom-gate/bottom-contact OTFT structure was deposited over highly-doped silicon substrates covered with thermally-grown oxide to detect vapor-phase compounds. A ten-fold organochloride and ammonia sensitivity compared to bare sensors corroborated the application of this semiconducting polymer in sensors. Furthermore, P3HT TFTs presented approximately three-order higher normalized sensitivity than any chemical sensor addressed herein. The results demonstrate that while TFTs respond linearly at the lowest concentration values herein, chemical sensors present such an operating regime mostly above 2000 ppm. Simultaneous alteration of charge carrier mobility and threshold voltage is responsible for pushing the detection limit down to units of ppm of ammonia, as well as tens of ppm of alcohol or ketones. Nevertheless, P3HT transistors and chemical sensors could compose an electronic nose operated at room temperature for a wide range concentration evaluation (1–10,000 ppm) of gaseous analytes. Targeted analytes include not only biomarkers for diseases, such as uremia, cirrhosis, lung cancer and diabetes, but also gases for environment monitoring in food, cosmetic and microelectronics industries. PMID:25912354

Comprehensive Performance Study of Magneto Cantilevers as a Candidate Model for Biological Sensors used in Lab-on-a-Chip Applications

PubMed Central

Saberkari, Hamidreza; Ghavifekr, Habib Badri; Shamsi, Mousa

2015-01-01

In recent years, demand for biological sensors which are capable of fast and accurate detection of minor amounts of pathogens in real-time form has been intensified. Acoustic wave (AW) devices whose performance is determined by mass sensitivity parameters and quality factor are used in biological sensors as platforms with high quality. Yet, current AW devices are facing many challenges such as the low value of their quality factor in practical applications and also their difficulty to use in liquids. The main focus of this article is to study on the magnetostrictive sensors which include milli/microcantilever (MSMC) type. In comparison with AW devices, MSMC has a lot of advantages; (1) its actuation and sensing unit is wirelessly controlled. (2) Its fabrication process is easy. (3) It works well in liquids. (4) It has a high-quality factor (in the air > 500). Simulation results demonstrate that the amount of quality factor depends on environment properties (density and viscosity), MSMC geometry, and its resonant behavior of harmonic modes. PMID:26120566

Active disturbance rejection control for output force creep characteristics of ionic polymer metal composites

NASA Astrophysics Data System (ADS)

Xiong, Yan; Chen, Yang; Sun, Zhiyong; Hao, Lina; Dong, Jie

2014-07-01

Ionic polymer metal composites (IPMCs) are a type of electroactive polymer (EAP) that can be used as both sensors and actuators. An IPMC has enormous potential application in the field of biomimetic robotics, medical devices, and so on. However, an IPMC actuator has a great number of disadvantages, such as creep and time-variation, making it vulnerable to external disturbances. In addition, the complex actuation mechanism makes it difficult to model and the demand of the control algorithm is laborious to implement. In this paper, we obtain a creep model of the IPMC by means of model identification based on the method of creep operator linear superposition. Although the mathematical model is not approximate to the IPMC accurate model, it is accurate enough to be used in MATLAB to prove the control algorithm. A controller based on the active disturbance rejection control (ADRC) method is designed to solve the drawbacks previously given. Because the ADRC controller is separate from the mathematical model of the controlled plant, the control algorithm has the ability to complete disturbance estimation and compensation. Some factors, such as all external disturbances, uncertainty factors, the inaccuracy of the identification model and different kinds of IPMCs, have little effect on controlling the output block force of the IPMC. Furthermore, we use the particle swarm optimization algorithm to adjust ADRC parameters so that the IPMC actuator can approach the desired block force with unknown external disturbances. Simulations and experimental examples validate the effectiveness of the ADRC controller.

Selected examples of intelligent (micro) sensor systems: state-of-the-art and tendencies

NASA Astrophysics Data System (ADS)

Hauptmann, Peter R.

2006-03-01

The capability of intelligent sensors to have more intelligence built into them continues to drive their application in areas including automotive, aerospace and defense, industrial, intelligent house and wear, medical and homeland security. In principle it is difficult to overestimate the importance of intelligent (micro) sensors or sensor systems within advanced societies but one characteristic feature is the global market for sensors, which is now about 20 billion annually. Therefore sensors or sensor systems play a dominant role in many fields from the macro sensor in manufacturing industry down to the miniaturized sensor for medical applications. The diversity of sensors precludes a complete description of the state-of-the-art; selected examples will illustrate the current situation. MEMS (microelectromechanical systems) devices are of special interest in the context of micro sensor systems. In past the main requirements of a sensor were in terms of metrological performance. The electrical (or optical) signal produced by the sensor needed to match the measure relatively accurately. Such basic functionality is no longer sufficient. Data processing near the sensor, the extraction of more information than just the direct sensor information by signal analysis, system aspects and multi-sensor information are the new demands. A shifting can be observed away from aiming to design perfect single-function transducers and towards the utilization of system-based sensors as system components. In the ideal case such systems contain sensors, actuators and electronics. They can be realized in monolithic, hybrid or discrete form—which kind is used depends on the application. In this article the state-of-the-art of intelligent sensors or sensor systems is reviewed using selected examples. Future trends are deduced.

End-To-End performance test of the LINC-NIRVANA Wavefront-Sensor system.

NASA Astrophysics Data System (ADS)

Berwein, Juergen; Bertram, Thomas; Conrad, Al; Briegel, Florian; Kittmann, Frank; Zhang, Xiangyu; Mohr, Lars

2011-09-01

LINC-NIRVANA is an imaging Fizeau interferometer, for use in near infrared wavelengths, being built for the Large Binocular Telescope. Multi-conjugate adaptive optics (MCAO) increases the sky coverage and the field of view over which diffraction limited images can be obtained. For its MCAO implementation, Linc-Nirvana utilizes four total wavefront sensors; each of the two beams is corrected by both a ground-layer wavefront sensor (GWS) and a high-layer wavefront sensor (HWS). The GWS controls the adaptive secondary deformable mirror (DM), which is based on an DSP slope computing unit. Whereas the HWS controls an internal DM via computations provided by an off-the-shelf multi-core Linux system. Using wavefront sensor data collected from a prior lab experiment, we have shown via simulation that the Linux based system is sufficient to operate at 1kHz, with jitter well below the needs of the final system. Based on that setup we tested the end-to-end performance and latency through all parts of the system which includes the camera, the wavefront controller, and the deformable mirror. We will present our loop control structure and the results of those performance tests.

An insula-frontostriatal network mediates flexible cognitive control by adaptively predicting changing control demands

PubMed Central

Jiang, Jiefeng; Beck, Jeffrey; Heller, Katherine; Egner, Tobias

2015-01-01

The anterior cingulate and lateral prefrontal cortices have been implicated in implementing context-appropriate attentional control, but the learning mechanisms underlying our ability to flexibly adapt the control settings to changing environments remain poorly understood. Here we show that human adjustments to varying control demands are captured by a reinforcement learner with a flexible, volatility-driven learning rate. Using model-based functional magnetic resonance imaging, we demonstrate that volatility of control demand is estimated by the anterior insula, which in turn optimizes the prediction of forthcoming demand in the caudate nucleus. The caudate's prediction of control demand subsequently guides the implementation of proactive and reactive attentional control in dorsal anterior cingulate and dorsolateral prefrontal cortices. These data enhance our understanding of the neuro-computational mechanisms of adaptive behaviour by connecting the classic cingulate-prefrontal cognitive control network to a subcortical control-learning mechanism that infers future demands by flexibly integrating remote and recent past experiences. PMID:26391305

Communications and information research: Improved space link performance via concatenated forward error correction coding

NASA Technical Reports Server (NTRS)

Rao, T. R. N.; Seetharaman, G.; Feng, G. L.

1996-01-01

With the development of new advanced instruments for remote sensing applications, sensor data will be generated at a rate that not only requires increased onboard processing and storage capability, but imposes demands on the space to ground communication link and ground data management-communication system. Data compression and error control codes provide viable means to alleviate these demands. Two types of data compression have been studied by many researchers in the area of information theory: a lossless technique that guarantees full reconstruction of the data, and a lossy technique which generally gives higher data compaction ratio but incurs some distortion in the reconstructed data. To satisfy the many science disciplines which NASA supports, lossless data compression becomes a primary focus for the technology development. While transmitting the data obtained by any lossless data compression, it is very important to use some error-control code. For a long time, convolutional codes have been widely used in satellite telecommunications. To more efficiently transform the data obtained by the Rice algorithm, it is required to meet the a posteriori probability (APP) for each decoded bit. A relevant algorithm for this purpose has been proposed which minimizes the bit error probability in the decoding linear block and convolutional codes and meets the APP for each decoded bit. However, recent results on iterative decoding of 'Turbo codes', turn conventional wisdom on its head and suggest fundamentally new techniques. During the past several months of this research, the following approaches have been developed: (1) a new lossless data compression algorithm, which is much better than the extended Rice algorithm for various types of sensor data, (2) a new approach to determine the generalized Hamming weights of the algebraic-geometric codes defined by a large class of curves in high-dimensional spaces, (3) some efficient improved geometric Goppa codes for disk memory systems and high-speed mass memory systems, and (4) a tree based approach for data compression using dynamic programming.

Space based optical staring sensor LOS determination and calibration using GCPs observation

NASA Astrophysics Data System (ADS)

Chen, Jun; An, Wei; Deng, Xinpu; Yang, Jungang; Sha, Zhichao

2016-10-01

Line of sight (LOS) attitude determination and calibration is the key prerequisite of tracking and location of targets in space based infrared (IR) surveillance systems (SBIRS) and the LOS determination and calibration of staring sensor is one of the difficulties. This paper provides a novel methodology for removing staring sensor bias through the use of Ground Control Points (GCPs) detected in the background field of the sensor. Based on researching the imaging model and characteristics of the staring sensor of SBIRS geostationary earth orbit part (GEO), the real time LOS attitude determination and calibration algorithm using landmark control point is proposed. The influential factors (including the thermal distortions error, assemble error, and so on) of staring sensor LOS attitude error are equivalent to bias angle of LOS attitude. By establishing the observation equation of GCPs and the state transition equation of bias angle, and using an extend Kalman filter (EKF), the real time estimation of bias angle and the high precision sensor LOS attitude determination and calibration are achieved. The simulation results show that the precision and timeliness of the proposed algorithm meet the request of target tracking and location process in space based infrared surveillance system.

New Approaches to Exciting Exergame-Experiences for People with Motor Function Impairments.

PubMed

Eckert, Martina; Gómez-Martinho, Ignacio; Meneses, Juan; Martínez, José-Fernán

2017-02-12

The work presented here suggests new ways to tackle exergames for physical rehabilitation and to improve the players' immersion and involvement. The primary (but not exclusive) purpose is to increase the motivation of children and adolescents with severe physical impairments, for doing their required exercises while playing. The proposed gaming environment is based on the Kinect sensor and the Blender Game Engine. A middleware has been implemented that efficiently transmits the data from the sensor to the game. Inside the game, different newly proposed mechanisms have been developed to distinguish pure exercise-gestures from other movements used to control the game (e.g., opening a menu). The main contribution is the amplification of weak movements, which allows the physically impaired to have similar gaming experiences as the average population. To test the feasibility of the proposed methods, four mini-games were implemented and tested by a group of 11 volunteers with different disabilities, most of them bound to a wheelchair. Their performance has also been compared to that of a healthy control group. Results are generally positive and motivating, although there is much to do to improve the functionalities. There is a major demand for applications that help to include disabled people in society and to improve their life conditions. This work will contribute towards providing them with more fun during exercise.

New Approaches to Exciting Exergame-Experiences for People with Motor Function Impairments

PubMed Central

Eckert, Martina; Gómez-Martinho, Ignacio; Meneses, Juan; Martínez, José-Fernán

2017-01-01

The work presented here suggests new ways to tackle exergames for physical rehabilitation and to improve the players’ immersion and involvement. The primary (but not exclusive) purpose is to increase the motivation of children and adolescents with severe physical impairments, for doing their required exercises while playing. The proposed gaming environment is based on the Kinect sensor and the Blender Game Engine. A middleware has been implemented that efficiently transmits the data from the sensor to the game. Inside the game, different newly proposed mechanisms have been developed to distinguish pure exercise-gestures from other movements used to control the game (e.g., opening a menu). The main contribution is the amplification of weak movements, which allows the physically impaired to have similar gaming experiences as the average population. To test the feasibility of the proposed methods, four mini-games were implemented and tested by a group of 11 volunteers with different disabilities, most of them bound to a wheelchair. Their performance has also been compared to that of a healthy control group. Results are generally positive and motivating, although there is much to do to improve the functionalities. There is a major demand for applications that help to include disabled people in society and to improve their life conditions. This work will contribute towards providing them with more fun during exercise. PMID:28208682

A Hybrid TDMA/CSMA-Based Wireless Sensor and Data Transmission Network for ORS Intra-Microsatellite Applications

PubMed Central

Wang, Long; Liu, Yong; Yin, Zengshan

2018-01-01

To achieve launch-on-demand for Operationally Responsive Space (ORS) missions, in this article, an intra-satellite wireless network (ISWN) is presented. It provides a wireless and modularized scheme for intra-spacecraft sensing and data buses. By removing the wired data bus, the commercial off-the-shelf (COTS) based wireless modular architecture will reduce both the volume and weight of the satellite platform, thus achieving rapid design and cost savings in development and launching. Based on the on-orbit data demand analysis, a hybrid time division multiple access/carrier sense multiple access (TDMA/CSMA) protocol is proposed. It includes an improved clear channel assessment (CCA) mechanism and a traffic adaptive slot allocation method. To analyze the access process, a Markov model is constructed. Then a detailed calculation is given in which the unsaturated cases are considered. Through simulations, the proposed protocol is proved to commendably satisfy the demands and performs better than existing schemes. It helps to build a full-wireless satellite instead of the current wired ones, and will contribute to provide dynamic space capabilities for ORS missions. PMID:29757243

A Hybrid TDMA/CSMA-Based Wireless Sensor and Data Transmission Network for ORS Intra-Microsatellite Applications.

PubMed

Wang, Long; Liu, Yong; Yin, Zengshan

2018-05-12

To achieve launch-on-demand for Operationally Responsive Space (ORS) missions, in this article, an intra-satellite wireless network (ISWN) is presented. It provides a wireless and modularized scheme for intra-spacecraft sensing and data buses. By removing the wired data bus, the commercial off-the-shelf (COTS) based wireless modular architecture will reduce both the volume and weight of the satellite platform, thus achieving rapid design and cost savings in development and launching. Based on the on-orbit data demand analysis, a hybrid time division multiple access/carrier sense multiple access (TDMA/CSMA) protocol is proposed. It includes an improved clear channel assessment (CCA) mechanism and a traffic adaptive slot allocation method. To analyze the access process, a Markov model is constructed. Then a detailed calculation is given in which the unsaturated cases are considered. Through simulations, the proposed protocol is proved to commendably satisfy the demands and performs better than existing schemes. It helps to build a full-wireless satellite instead of the current wired ones, and will contribute to provide dynamic space capabilities for ORS missions.

Seamless positioning and navigation by using geo-referenced images and multi-sensor data.

PubMed

Li, Xun; Wang, Jinling; Li, Tao

2013-07-12

Ubiquitous positioning is considered to be a highly demanding application for today's Location-Based Services (LBS). While satellite-based navigation has achieved great advances in the past few decades, positioning and navigation in indoor scenarios and deep urban areas has remained a challenging topic of substantial research interest. Various strategies have been adopted to fill this gap, within which vision-based methods have attracted growing attention due to the widespread use of cameras on mobile devices. However, current vision-based methods using image processing have yet to revealed their full potential for navigation applications and are insufficient in many aspects. Therefore in this paper, we present a hybrid image-based positioning system that is intended to provide seamless position solution in six degrees of freedom (6DoF) for location-based services in both outdoor and indoor environments. It mainly uses visual sensor input to match with geo-referenced images for image-based positioning resolution, and also takes advantage of multiple onboard sensors, including the built-in GPS receiver and digital compass to assist visual methods. Experiments demonstrate that such a system can greatly improve the position accuracy for areas where the GPS signal is negatively affected (such as in urban canyons), and it also provides excellent position accuracy for indoor environments.

Seamless Positioning and Navigation by Using Geo-Referenced Images and Multi-Sensor Data

PubMed Central

Li, Xun; Wang, Jinling; Li, Tao

2013-01-01

Ubiquitous positioning is considered to be a highly demanding application for today's Location-Based Services (LBS). While satellite-based navigation has achieved great advances in the past few decades, positioning and navigation in indoor scenarios and deep urban areas has remained a challenging topic of substantial research interest. Various strategies have been adopted to fill this gap, within which vision-based methods have attracted growing attention due to the widespread use of cameras on mobile devices. However, current vision-based methods using image processing have yet to revealed their full potential for navigation applications and are insufficient in many aspects. Therefore in this paper, we present a hybrid image-based positioning system that is intended to provide seamless position solution in six degrees of freedom (6DoF) for location-based services in both outdoor and indoor environments. It mainly uses visual sensor input to match with geo-referenced images for image-based positioning resolution, and also takes advantage of multiple onboard sensors, including the built-in GPS receiver and digital compass to assist visual methods. Experiments demonstrate that such a system can greatly improve the position accuracy for areas where the GPS signal is negatively affected (such as in urban canyons), and it also provides excellent position accuracy for indoor environments. PMID:23857267

A cost-effective intelligent robotic system with dual-arm dexterous coordination and real-time vision

NASA Technical Reports Server (NTRS)

Marzwell, Neville I.; Chen, Alexander Y. K.

1991-01-01

Dexterous coordination of manipulators based on the use of redundant degrees of freedom, multiple sensors, and built-in robot intelligence represents a critical breakthrough in development of advanced manufacturing technology. A cost-effective approach for achieving this new generation of robotics has been made possible by the unprecedented growth of the latest microcomputer and network systems. The resulting flexible automation offers the opportunity to improve the product quality, increase the reliability of the manufacturing process, and augment the production procedures for optimizing the utilization of the robotic system. Moreover, the Advanced Robotic System (ARS) is modular in design and can be upgraded by closely following technological advancements as they occur in various fields. This approach to manufacturing automation enhances the financial justification and ensures the long-term profitability and most efficient implementation of robotic technology. The new system also addresses a broad spectrum of manufacturing demand and has the potential to address both complex jobs as well as highly labor-intensive tasks. The ARS prototype employs the decomposed optimization technique in spatial planning. This technique is implemented to the framework of the sensor-actuator network to establish the general-purpose geometric reasoning system. The development computer system is a multiple microcomputer network system, which provides the architecture for executing the modular network computing algorithms. The knowledge-based approach used in both the robot vision subsystem and the manipulation control subsystems results in the real-time image processing vision-based capability. The vision-based task environment analysis capability and the responsive motion capability are under the command of the local intelligence centers. An array of ultrasonic, proximity, and optoelectronic sensors is used for path planning. The ARS currently has 18 degrees of freedom made up by two articulated arms, one movable robot head, and two charged coupled device (CCD) cameras for producing the stereoscopic views, and articulated cylindrical-type lower body, and an optional mobile base. A functional prototype is demonstrated.

Highly Sensitive Bulk Silicon Chemical Sensors with Sub-5 nm Thin Charge Inversion Layers.

PubMed

Fahad, Hossain M; Gupta, Niharika; Han, Rui; Desai, Sujay B; Javey, Ali

2018-03-27

There is an increasing demand for mass-producible, low-power gas sensors in a wide variety of industrial and consumer applications. Here, we report chemical-sensitive field-effect-transistors (CS-FETs) based on bulk silicon wafers, wherein an electrostatically confined sub-5 nm thin charge inversion layer is modulated by chemical exposure to achieve a high-sensitivity gas-sensing platform. Using hydrogen sensing as a "litmus" test, we demonstrate large sensor responses (>1000%) to 0.5% H 2 gas, with fast response (<60 s) and recovery times (<120 s) at room temperature and low power (<50 μW). On the basis of these performance metrics as well as standardized benchmarking, we show that bulk silicon CS-FETs offer similar or better sensing performance compared to emerging nanostructures semiconductors while providing a highly scalable and manufacturable platform.

High-Temperature Gas Sensor Array (Electronic Nose) Demonstrated

NASA Technical Reports Server (NTRS)

Hunter, Gary W.

2002-01-01

The ability to measure emissions from aeronautic engines and in commercial applications such as automotive emission control and chemical process monitoring is a necessary first step if one is going to actively control those emissions. One single sensor will not give all the information necessary to determine the chemical composition of a high-temperature, harsh environment. Rather, an array of gas sensor arrays--in effect, a high-temperature electronic "nose"--is necessary to characterize the chemical constituents of a diverse, high-temperature environment, such as an emissions stream. The signals produced by this nose could be analyzed to determine the constituents of the emission stream. Although commercial electronic noses for near-room temperature applications exist, they often depend significantly on lower temperature materials or only one sensor type. A separate development effort necessary for a high-temperature electronic nose is being undertaken by the NASA Glenn Research Center, Case Western Reserve University, Ohio State University, and Makel Engineering, Inc. The sensors are specially designed for hightemperature environments. A first-generation high-temperature electronic nose has been demonstrated on a modified automotive engine. This nose sensor array was composed of sensors designed for hightemperature environments fabricated using microelectromechanical-systems- (MEMS-) based technology. The array included a tin-oxide-based sensor doped for nitrogen oxide (NOx) sensitivity, a SiC-based hydrocarbon (CxHy) sensor, and an oxygen sensor (O2). These sensors operate on different principles--resistor, diode, and electrochemical cell, respectively--and each sensor has very different responses to the individual gases in the environment. A picture showing the sensor head for the array is shown in the photograph on the left and the sensors installed in the engine are shown in the photograph on the right. Electronics are interfaced with the sensors for temperature control and signal conditioning, and packaging designed for high temperatures is necessary for the array to survive the engine environment.

Implementation of a High-Speed FPGA and DSP Based FFT Processor for Improving Strain Demodulation Performance in a Fiber-Optic-Based Sensing System

NASA Technical Reports Server (NTRS)

Farley, Douglas L.

2005-01-01

NASA's Aviation Safety and Security Program is pursuing research in on-board Structural Health Management (SHM) technologies for purposes of reducing or eliminating aircraft accidents due to system and component failures. Under this program, NASA Langley Research Center (LaRC) is developing a strain-based structural health-monitoring concept that incorporates a fiber optic-based measuring system for acquiring strain values. This fiber optic-based measuring system provides for the distribution of thousands of strain sensors embedded in a network of fiber optic cables. The resolution of strain value at each discrete sensor point requires a computationally demanding data reduction software process that, when hosted on a conventional processor, is not suitable for near real-time measurement. This report describes the development and integration of an alternative computing environment using dedicated computing hardware for performing the data reduction. Performance comparison between the existing and the hardware-based system is presented.

Hall-Effect Based Semi-Fast AC On-Board Charging Equipment for Electric Vehicles

PubMed Central

Milanés-Montero, María Isabel; Gallardo-Lozano, Javier; Romero-Cadaval, Enrique; González-Romera, Eva

2011-01-01

The expected increase in the penetration of electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) will produce unbalanced conditions, reactive power consumption and current harmonics drawn by the battery charging equipment, causing a great impact on the power quality of the future smart grid. A single-phase semi-fast electric vehicle battery charger is proposed in this paper. This ac on-board charging equipment can operate in grid-to-vehicle (G2V) mode, and also in vehicle-to-grid (V2G) mode, transferring the battery energy to the grid when the vehicle is parked. The charger is controlled with a Perfect Harmonic Cancellation (PHC) strategy, contributing to improve the grid power quality, since the current demanded or injected has no harmonic content and a high power factor. Hall-effect current and voltage transducers have been used in the sensor stage to carry out this control strategy. Experimental results with a laboratory prototype are presented. PMID:22163697

Hall-effect based semi-fast AC on-board charging equipment for electric vehicles.

PubMed

Milanés-Montero, María Isabel; Gallardo-Lozano, Javier; Romero-Cadaval, Enrique; González-Romera, Eva

2011-01-01

The expected increase in the penetration of electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) will produce unbalanced conditions, reactive power consumption and current harmonics drawn by the battery charging equipment, causing a great impact on the power quality of the future smart grid. A single-phase semi-fast electric vehicle battery charger is proposed in this paper. This ac on-board charging equipment can operate in grid-to-vehicle (G2V) mode, and also in vehicle-to-grid (V2G) mode, transferring the battery energy to the grid when the vehicle is parked. The charger is controlled with a Perfect Harmonic Cancellation (PHC) strategy, contributing to improve the grid power quality, since the current demanded or injected has no harmonic content and a high power factor. Hall-effect current and voltage transducers have been used in the sensor stage to carry out this control strategy. Experimental results with a laboratory prototype are presented.

Controllable rectification of the axial expansion in the thermally driven artificial muscle

NASA Astrophysics Data System (ADS)

Yue, Donghua; Zhang, Xingyi; Yong, Huadong; Zhou, Jun; Zhou, You-He

2015-09-01

At present, the concept of artificial muscle twisted by polymers or fibers has become a hot issue in the field of intelligent material research according to its distinguishing advantages, e.g., high energy density, large-stroke, non-hysteresis, and inexpensive. The axial thermal expansion coefficient is an important parameter which can affect its demanding applications. In this letter, a device with high accuracy capacitive sensor is constructed to measure the axial thermal expansion coefficient of the twisted carbon fibers and yarns of Kevlar, and a theoretical model based on the thermal elasticity and the geometrical features of the twisted structure are also presented to predict the axial expansion coefficient. It is found that the calculated results take good agreements with the experimental data. According to the present experiment and analyses, a method to control the axial thermal expansion coefficient of artificial muscle is proposed. Moreover, the mechanism of this kind of thermally driven artificial muscle is discussed.

The Benefits of Soft Sensor and Multi-Rate Control for the Implementation of Wireless Networked Control Systems

PubMed Central

Mansano, Raul K.; Godoy, Eduardo P.; Porto, Arthur J. V.

2014-01-01

Recent advances in wireless networking technology and the proliferation of industrial wireless sensors have led to an increasing interest in using wireless networks for closed loop control. The main advantages of Wireless Networked Control Systems (WNCSs) are the reconfigurability, easy commissioning and the possibility of installation in places where cabling is impossible. Despite these advantages, there are two main problems which must be considered for practical implementations of WNCSs. One problem is the sampling period constraint of industrial wireless sensors. This problem is related to the energy cost of the wireless transmission, since the power supply is limited, which precludes the use of these sensors in several closed-loop controls. The other technological concern in WNCS is the energy efficiency of the devices. As the sensors are powered by batteries, the lowest possible consumption is required to extend battery lifetime. As a result, there is a compromise between the sensor sampling period, the sensor battery lifetime and the required control performance for the WNCS. This paper develops a model-based soft sensor to overcome these problems and enable practical implementations of WNCSs. The goal of the soft sensor is generating virtual data allowing an actuation on the process faster than the maximum sampling period available for the wireless sensor. Experimental results have shown the soft sensor is a solution to the sampling period constraint problem of wireless sensors in control applications, enabling the application of industrial wireless sensors in WNCSs. Additionally, our results demonstrated the soft sensor potential for implementing energy efficient WNCS through the battery saving of industrial wireless sensors. PMID:25529208

A Time Tree Medium Access Control for Energy Efficiency and Collision Avoidance in Wireless Sensor Networks

PubMed Central

Lee, Kilhung

2010-01-01

This paper presents a medium access control and scheduling scheme for wireless sensor networks. It uses time trees for sending data from the sensor node to the base station. For an energy efficient operation of the sensor networks in a distributed manner, time trees are built in order to reduce the collision probability and to minimize the total energy required to send data to the base station. A time tree is a data gathering tree where the base station is the root and each sensor node is either a relaying or a leaf node of the tree. Each tree operates in a different time schedule with possibly different activation rates. Through the simulation, the proposed scheme that uses time trees shows better characteristics toward burst traffic than the previous energy and data arrival rate scheme. PMID:22319270

Studies of prototype DEPFET sensors for the Wide Field Imager of Athena

NASA Astrophysics Data System (ADS)

Treberspurg, Wolfgang; Andritschke, Robert; Bähr, Alexander; Behrens, Annika; Hauser, Günter; Lechner, Peter; Meidinger, Norbert; Müller-Seidlitz, Johannes; Treis, Johannes

2017-08-01

The Wide Field Imager (WFI) of ESA's next X-ray observatory Athena will combine a high count rate capability with a large field of view, both with state-of-the-art spectroscopic performance. To meet these demands, specific DEPFET active pixel detectors have been developed and operated. Due to the intrinsic amplification of detected signals they are best suited to achieve a high speed and low noise performance. Different fabrication technologies and transistor geometries have been implemented on a dedicated prototype production in the course of the development of the DEPFET sensors. The main modifications between the sensors concern the shape of the transistor gate - regarding the layout - and the thickness of the gate oxide - regarding the technology. To facilitate the fabrication and testing of the resulting variety of sensors the presented studies were carried out with 64×64 pixel detectors. The detector comprises a control ASIC (Switcher-A), a readout ASIC (VERITAS- 2) and the sensor. In this paper we give an overview on the evaluation of different prototype sensors. The most important results, which have been decisive for the identification of the optimal fabrication technology and transistor layout for subsequent sensor productions are summarized. It will be shown that the developments result in an excellent performance of spectroscopic X-ray DEPFETs with typical noise values below 2.5 ENC at 2.5 μs/row.

Engine control system having fuel-based adjustment

DOEpatents

Willi, Martin L [Dunlap, IL; Fiveland, Scott B [Metamora, IL; Montgomery, David T [Edelstein, IL; Gong, Weidong [Dunlap, IL

2011-03-15

A control system for an engine having a cylinder is disclosed having an engine valve configured to affect a fluid flow of the cylinder, an actuator configured to move the engine valve, and an in-cylinder sensor configured to generate a signal indicative of a characteristic of fuel entering the cylinder. The control system also has a controller in communication with the actuator and the sensor. The controller is configured to determine the characteristic of the fuel based on the signal and selectively regulate the actuator to adjust a timing of the engine valve based on the characteristic of the fuel.

Progress of Mimetic Enzymes and Their Applications in Chemical Sensors.

PubMed

Yang, Bin; Li, Jianping; Deng, Huan; Zhang, Lianming

2016-11-01

The need to develop innovative and reformative approaches to synthesize chemical sensors has increased in recent years because of demands for selectivity, stability, and reproducibility. Mimetic enzymes provide an efficient and convenient method for chemical sensors. This review summarizes the application of mimetic enzymes in chemical sensors. Mimetic enzymes can be classified into five categories: hydrolases, oxidoreductases, transferases, isomerases, and induced enzymes. Potential and recent applications of mimetic enzymes in chemical sensors are reviewed in detail, and the outlook of profound development has been illustrated.

A New Controller for a Smart Walker Based on Human-Robot Formation

PubMed Central

Valadão, Carlos; Caldeira, Eliete; Bastos-Filho, Teodiano; Frizera-Neto, Anselmo; Carelli, Ricardo

2016-01-01

This paper presents the development of a smart walker that uses a formation controller in its displacements. Encoders, a laser range finder and ultrasound are the sensors used in the walker. The control actions are based on the user (human) location, who is the actual formation leader. There is neither a sensor attached to the user’s body nor force sensors attached to the arm supports of the walker, and thus, the control algorithm projects the measurements taken from the laser sensor into the user reference and, then, calculates the linear and angular walker’s velocity to keep the formation (distance and angle) in relation to the user. An algorithm was developed to detect the user’s legs, whose distances from the laser sensor provide the information necessary to the controller. The controller was theoretically analyzed regarding its stability, simulated and validated with real users, showing accurate performance in all experiments. In addition, safety rules are used to check both the user and the device conditions, in order to guarantee that the user will not have any risks when using the smart walker. The applicability of this device is for helping people with lower limb mobility impairments. PMID:27447634

Simple laser vision sensor calibration for surface profiling applications

NASA Astrophysics Data System (ADS)

Abu-Nabah, Bassam A.; ElSoussi, Adnane O.; Al Alami, Abed ElRahman K.

2016-09-01

Due to the relatively large structures in the Oil and Gas industry, original equipment manufacturers (OEMs) have been implementing custom-designed laser vision sensor (LVS) surface profiling systems as part of quality control in their manufacturing processes. The rough manufacturing environment and the continuous movement and misalignment of these custom-designed tools adversely affect the accuracy of laser-based vision surface profiling applications. Accordingly, Oil and Gas businesses have been raising the demand from the OEMs to implement practical and robust LVS calibration techniques prior to running any visual inspections. This effort introduces an LVS calibration technique representing a simplified version of two known calibration techniques, which are commonly implemented to obtain a calibrated LVS system for surface profiling applications. Both calibration techniques are implemented virtually and experimentally to scan simulated and three-dimensional (3D) printed features of known profiles, respectively. Scanned data is transformed from the camera frame to points in the world coordinate system and compared with the input profiles to validate the introduced calibration technique capability against the more complex approach and preliminarily assess the measurement technique for weld profiling applications. Moreover, the sensitivity to stand-off distances is analyzed to illustrate the practicality of the presented technique.

An ultra low-power and traffic-adaptive medium access control protocol for wireless body area network.

PubMed

Ullah, Sana; Kwak, Kyung Sup

2012-06-01

Wireless Body Area Network (WBAN) consists of low-power, miniaturized, and autonomous wireless sensor nodes that enable physicians to remotely monitor vital signs of patients and provide real-time feedback with medical diagnosis and consultations. It is the most reliable and cheaper way to take care of patients suffering from chronic diseases such as asthma, diabetes and cardiovascular diseases. Some of the most important attributes of WBAN is low-power consumption and delay. This can be achieved by introducing flexible duty cycling techniques on the energy constraint sensor nodes. Stated otherwise, low duty cycle nodes should not receive frequent synchronization and control packets if they have no data to send/receive. In this paper, we introduce a Traffic-adaptive MAC protocol (TaMAC) by taking into account the traffic information of the sensor nodes. The protocol dynamically adjusts the duty cycle of the sensor nodes according to their traffic-patterns, thus solving the idle listening and overhearing problems. The traffic-patterns of all sensor nodes are organized and maintained by the coordinator. The TaMAC protocol is supported by a wakeup radio that is used to accommodate emergency and on-demand events in a reliable manner. The wakeup radio uses a separate control channel along with the data channel and therefore it has considerably low power consumption requirements. Analytical expressions are derived to analyze and compare the performance of the TaMAC protocol with the well-known beacon-enabled IEEE 802.15.4 MAC, WiseMAC, and SMAC protocols. The analytical derivations are further validated by simulation results. It is shown that the TaMAC protocol outperforms all other protocols in terms of power consumption and delay.

A Human Serum-Based Enzyme-Free Continuous Glucose Monitoring Technique Using a Needle-Type Bio-Layer Interference Sensor

PubMed Central

Seo, Dongmin; Paek, Sung-Ho; Oh, Sangwoo; Seo, Sungkyu; Paek, Se-Hwan

2016-01-01

The incidence of diabetes is continually increasing, and by 2030, it is expected to have increased by 69% and 20% in underdeveloped and developed countries, respectively. Therefore, glucose sensors are likely to remain in high demand in medical device markets. For the current study, we developed a needle-type bio-layer interference (BLI) sensor that can continuously monitor glucose levels. Using dialysis procedures, we were able to obtain hypoglycemic samples from commercial human serum. These dialysis-derived samples, alongside samples of normal human serum were used to evaluate the utility of the sensor for the detection of the clinical interest range of glucose concentrations (70–200 mg/dL), revealing high system performance for a wide glycemic state range (45–500 mg/dL). Reversibility and reproducibility were also tested over a range of time spans. Combined with existing BLI system technology, this sensor holds great promise for use as a wearable online continuous glucose monitoring system for patients in a hospital setting. PMID:27669267

Study on dynamic response measurement of the submarine pipeline by full-term FBG sensors.

PubMed

Zhou, Jinghai; Sun, Li; Li, Hongnan

2014-01-01

The field of structural health monitoring is concerned with accurately and reliably assessing the integrity of a given structure to reduce ownership costs, increase operational lifetime, and improve safety. In structural health monitoring systems, fiber Bragg grating (FBG) is a promising measurement technology for its superior ability of explosion proof, immunity to electromagnetic interference, and high accuracy. This paper is a study on the dynamic characteristics of fiber Bragg grating (FBG) sensors applied to a submarine pipeline, as well as an experimental investigation on a laboratory model of the pipeline. The dynamic response of a submarine pipeline under seismic excitation is a coupled vibration of liquid and solid interaction. FBG sensors and strain gauges are used to monitor the dynamic response of a submarine pipeline model under a variety of dynamic loading conditions and the maximum working frequency of an FBG strain sensor is calculated according to its dynamic strain responses. Based on the theoretical and experimental results, it can be concluded that FBG sensor is superior to strain gauge and satisfies the demand of dynamic strain measurement.

Study on Dynamic Response Measurement of the Submarine Pipeline by Full-Term FBG Sensors

PubMed Central

Zhou, Jinghai; Sun, Li; Li, Hongnan

2014-01-01

The field of structural health monitoring is concerned with accurately and reliably assessing the integrity of a given structure to reduce ownership costs, increase operational lifetime, and improve safety. In structural health monitoring systems, fiber Bragg grating (FBG) is a promising measurement technology for its superior ability of explosion proof, immunity to electromagnetic interference, and high accuracy. This paper is a study on the dynamic characteristics of fiber Bragg grating (FBG) sensors applied to a submarine pipeline, as well as an experimental investigation on a laboratory model of the pipeline. The dynamic response of a submarine pipeline under seismic excitation is a coupled vibration of liquid and solid interaction. FBG sensors and strain gauges are used to monitor the dynamic response of a submarine pipeline model under a variety of dynamic loading conditions and the maximum working frequency of an FBG strain sensor is calculated according to its dynamic strain responses. Based on the theoretical and experimental results, it can be concluded that FBG sensor is superior to strain gauge and satisfies the demand of dynamic strain measurement. PMID:24971391