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Sample records for acoustic sensor network

  1. Acoustic sensor networks for woodpecker localization

    NASA Astrophysics Data System (ADS)

    Wang, H.; Chen, C. E.; Ali, A.; Asgari, S.; Hudson, R. E.; Yao, K.; Estrin, D.; Taylor, C.

    2005-08-01

    Sensor network technology can revolutionize the study of animal ecology by providing a means of non-intrusive, simultaneous monitoring of interaction among multiple animals. In this paper, we investigate design, analysis, and testing of acoustic arrays for localizing acorn woodpeckers using their vocalizations. Each acoustic array consists of four microphones arranged in a square. All four audio channels within the same acoustic array are finely synchronized within a few micro seconds. We apply the approximate maximum likelihood (AML) method to synchronized audio channels of each acoustic array for estimating the direction-of-arrival (DOA) of woodpecker vocalizations. The woodpecker location is estimated by applying least square (LS) methods to DOA bearing crossings of multiple acoustic arrays. We have revealed the critical relation between microphone spacing of acoustic arrays and robustness of beamforming of woodpecker vocalizations. Woodpecker localization experiments using robust array element spacing in different types of environments are conducted and compared. Practical issues about calibration of acoustic array orientation are also discussed.

  2. On Modeling Eavesdropping Attacks in Underwater Acoustic Sensor Networks.

    PubMed

    Wang, Qiu; Dai, Hong-Ning; Li, Xuran; Wang, Hao; Xiao, Hong

    2016-01-01

    The security and privacy of underwater acoustic sensor networks has received extensive attention recently due to the proliferation of underwater activities. This paper proposes an analytical model to investigate the eavesdropping attacks in underwater acoustic sensor networks. Our analytical framework considers the impacts of various underwater acoustic channel conditions (such as the acoustic signal frequency, spreading factor and wind speed) and different hydrophones (isotropic hydrophones and array hydrophones) in terms of network nodes and eavesdroppers. We also conduct extensive simulations to evaluate the effectiveness and the accuracy of our proposed model. Empirical results show that our proposed model is quite accurate. In addition, our results also imply that the eavesdropping probability heavily depends on both the underwater acoustic channel conditions and the features of hydrophones. PMID:27213379

  3. On Modeling Eavesdropping Attacks in Underwater Acoustic Sensor Networks.

    PubMed

    Wang, Qiu; Dai, Hong-Ning; Li, Xuran; Wang, Hao; Xiao, Hong

    2016-05-18

    The security and privacy of underwater acoustic sensor networks has received extensive attention recently due to the proliferation of underwater activities. This paper proposes an analytical model to investigate the eavesdropping attacks in underwater acoustic sensor networks. Our analytical framework considers the impacts of various underwater acoustic channel conditions (such as the acoustic signal frequency, spreading factor and wind speed) and different hydrophones (isotropic hydrophones and array hydrophones) in terms of network nodes and eavesdroppers. We also conduct extensive simulations to evaluate the effectiveness and the accuracy of our proposed model. Empirical results show that our proposed model is quite accurate. In addition, our results also imply that the eavesdropping probability heavily depends on both the underwater acoustic channel conditions and the features of hydrophones.

  4. On Modeling Eavesdropping Attacks in Underwater Acoustic Sensor Networks

    PubMed Central

    Wang, Qiu; Dai, Hong-Ning; Li, Xuran; Wang, Hao; Xiao, Hong

    2016-01-01

    The security and privacy of underwater acoustic sensor networks has received extensive attention recently due to the proliferation of underwater activities. This paper proposes an analytical model to investigate the eavesdropping attacks in underwater acoustic sensor networks. Our analytical framework considers the impacts of various underwater acoustic channel conditions (such as the acoustic signal frequency, spreading factor and wind speed) and different hydrophones (isotropic hydrophones and array hydrophones) in terms of network nodes and eavesdroppers. We also conduct extensive simulations to evaluate the effectiveness and the accuracy of our proposed model. Empirical results show that our proposed model is quite accurate. In addition, our results also imply that the eavesdropping probability heavily depends on both the underwater acoustic channel conditions and the features of hydrophones. PMID:27213379

  5. A secure communication suite for underwater acoustic sensor networks.

    PubMed

    Dini, Gianluca; Lo Duca, Angelica

    2012-01-01

    In this paper we describe a security suite for Underwater Acoustic Sensor Networks comprising both fixed and mobile nodes. The security suite is composed of a secure routing protocol and a set of cryptographic primitives aimed at protecting the confidentiality and the integrity of underwater communication while taking into account the unique characteristics and constraints of the acoustic channel. By means of experiments and simulations based on real data, we show that the suite is suitable for an underwater networking environment as it introduces limited, and sometimes negligible, communication and power consumption overhead.

  6. A Secure Communication Suite for Underwater Acoustic Sensor Networks

    PubMed Central

    Dini, Gianluca; Duca, Angelica Lo

    2012-01-01

    In this paper we describe a security suite for Underwater Acoustic Sensor Networks comprising both fixed and mobile nodes. The security suite is composed of a secure routing protocol and a set of cryptographic primitives aimed at protecting the confidentiality and the integrity of underwater communication while taking into account the unique characteristics and constraints of the acoustic channel. By means of experiments and simulations based on real data, we show that the suite is suitable for an underwater networking environment as it introduces limited, and sometimes negligible, communication and power consumption overhead. PMID:23202204

  7. Current capability of a matured disposable acoustic sensor network

    NASA Astrophysics Data System (ADS)

    Beale, D. A. R.; Geddes, N. J., II; Hume, A.; Gray, A. J.

    2006-05-01

    In response to the needs of the UK MOD QinetiQ have designed, developed and trialled an ad-hoc, self organising network of acoustic nodes for in-depth deployment that can detect and track military targets in a range of environments and for all types of weapon locating. Research conducted has shown that disposable technologies are sufficiently mature to provide a useful military capability. Work this year has included a 3 month series of trials to exercise the prototype equipment and has provided an indication of in-service capability across a broad range of environments. This paper will discuss the scientific approach that was applied to the development of the equipment, from early laboratory development through to the prototype sensor network deployment in operationally representative environments. Highlights from the trials have been provided. New findings from the fusion of a low cost thermal imager that can be cued by the acoustic network are also discussed.

  8. Localization with a mobile beacon in underwater acoustic sensor networks.

    PubMed

    Lee, Sangho; Kim, Kiseon

    2012-01-01

    Localization is one of the most important issues associated with underwater acoustic sensor networks, especially when sensor nodes are randomly deployed. Given that it is difficult to deploy beacon nodes at predetermined locations, localization schemes with a mobile beacon on the sea surface or along the planned path are inherently convenient, accurate, and energy-efficient. In this paper, we propose a new range-free Localization with a Mobile Beacon (LoMoB). The mobile beacon periodically broadcasts a beacon message containing its location. Sensor nodes are individually localized by passively receiving the beacon messages without inter-node communications. For location estimation, a set of potential locations are obtained as candidates for a node's location and then the node's location is determined through the weighted mean of all the potential locations with the weights computed based on residuals.

  9. A Survey on Underwater Acoustic Sensor Network Routing Protocols.

    PubMed

    Li, Ning; Martínez, José-Fernán; Meneses Chaus, Juan Manuel; Eckert, Martina

    2016-03-22

    Underwater acoustic sensor networks (UASNs) have become more and more important in ocean exploration applications, such as ocean monitoring, pollution detection, ocean resource management, underwater device maintenance, etc. In underwater acoustic sensor networks, since the routing protocol guarantees reliable and effective data transmission from the source node to the destination node, routing protocol design is an attractive topic for researchers. There are many routing algorithms have been proposed in recent years. To present the current state of development of UASN routing protocols, we review herein the UASN routing protocol designs reported in recent years. In this paper, all the routing protocols have been classified into different groups according to their characteristics and routing algorithms, such as the non-cross-layer design routing protocol, the traditional cross-layer design routing protocol, and the intelligent algorithm based routing protocol. This is also the first paper that introduces intelligent algorithm-based UASN routing protocols. In addition, in this paper, we investigate the development trends of UASN routing protocols, which can provide researchers with clear and direct insights for further research.

  10. A Survey on Underwater Acoustic Sensor Network Routing Protocols

    PubMed Central

    Li, Ning; Martínez, José-Fernán; Meneses Chaus, Juan Manuel; Eckert, Martina

    2016-01-01

    Underwater acoustic sensor networks (UASNs) have become more and more important in ocean exploration applications, such as ocean monitoring, pollution detection, ocean resource management, underwater device maintenance, etc. In underwater acoustic sensor networks, since the routing protocol guarantees reliable and effective data transmission from the source node to the destination node, routing protocol design is an attractive topic for researchers. There are many routing algorithms have been proposed in recent years. To present the current state of development of UASN routing protocols, we review herein the UASN routing protocol designs reported in recent years. In this paper, all the routing protocols have been classified into different groups according to their characteristics and routing algorithms, such as the non-cross-layer design routing protocol, the traditional cross-layer design routing protocol, and the intelligent algorithm based routing protocol. This is also the first paper that introduces intelligent algorithm-based UASN routing protocols. In addition, in this paper, we investigate the development trends of UASN routing protocols, which can provide researchers with clear and direct insights for further research. PMID:27011193

  11. A Survey on Underwater Acoustic Sensor Network Routing Protocols.

    PubMed

    Li, Ning; Martínez, José-Fernán; Meneses Chaus, Juan Manuel; Eckert, Martina

    2016-01-01

    Underwater acoustic sensor networks (UASNs) have become more and more important in ocean exploration applications, such as ocean monitoring, pollution detection, ocean resource management, underwater device maintenance, etc. In underwater acoustic sensor networks, since the routing protocol guarantees reliable and effective data transmission from the source node to the destination node, routing protocol design is an attractive topic for researchers. There are many routing algorithms have been proposed in recent years. To present the current state of development of UASN routing protocols, we review herein the UASN routing protocol designs reported in recent years. In this paper, all the routing protocols have been classified into different groups according to their characteristics and routing algorithms, such as the non-cross-layer design routing protocol, the traditional cross-layer design routing protocol, and the intelligent algorithm based routing protocol. This is also the first paper that introduces intelligent algorithm-based UASN routing protocols. In addition, in this paper, we investigate the development trends of UASN routing protocols, which can provide researchers with clear and direct insights for further research. PMID:27011193

  12. Locating Acoustic Events Based on Large-Scale Sensor Networks

    PubMed Central

    Kim, Yungeun; Ahn, Junho; Cha, Hojung

    2009-01-01

    Research on acoustic source localization is actively being conducted to enhance accuracy and coverage. However, the performance is inherently limited due to the use of expensive sensor nodes and inefficient communication methods. This paper proposes an acoustic source localization algorithm for a large area that uses low-cost sensor nodes. The proposed mechanism efficiently handles multiple acoustic sources by removing false-positive errors that arise from the different propagation ranges of radio and sound. Extensive outdoor experiments with real hardware validated that the proposed mechanism could localize four acoustic sources within a 3 m error in a 60 m by 60 m area, where conventional systems could hardly achieve similar performance. PMID:22303155

  13. On the selection of transmission range in underwater acoustic sensor networks.

    PubMed

    Gao, Mingsheng; Foh, Chuan Heng; Cai, Jianfei

    2012-01-01

    Transmission range plays an important role in the deployment of a practical underwater acoustic sensor network (UWSN), where sensor nodes equipping with only basic functions are deployed at random locations with no particular geometrical arrangements. The selection of the transmission range directly influences the energy efficiency and the network connectivity of such a random network. In this paper, we seek analytical modeling to investigate the tradeoff between the energy efficiency and the network connectivity through the selection of the transmission range. Our formulation offers a design guideline for energy-efficient packet transmission operation given a certain network connectivity requirement.

  14. A reverse localization scheme for underwater acoustic sensor networks.

    PubMed

    Moradi, Marjan; Rezazadeh, Javad; Ismail, Abdul Samad

    2012-01-01

    Underwater Wireless Sensor Networks (UWSNs) provide new opportunities to observe and predict the behavior of aquatic environments. In some applications like target tracking or disaster prevention, sensed data is meaningless without location information. In this paper, we propose a novel 3D centralized, localization scheme for mobile underwater wireless sensor network, named Reverse Localization Scheme or RLS in short. RLS is an event-driven localization method triggered by detector sensors for launching localization process. RLS is suitable for surveillance applications that require very fast reactions to events and could report the location of the occurrence. In this method, mobile sensor nodes report the event toward the surface anchors as soon as they detect it. They do not require waiting to receive location information from anchors. Simulation results confirm that the proposed scheme improves the energy efficiency and reduces significantly localization response time with a proper level of accuracy in terms of mobility model of water currents. Major contributions of this method lie on reducing the numbers of message exchange for localization, saving the energy and decreasing the average localization response time.

  15. A Reverse Localization Scheme for Underwater Acoustic Sensor Networks

    PubMed Central

    Moradi, Marjan; Rezazadeh, Javad; Ismail, Abdul Samad

    2012-01-01

    Underwater Wireless Sensor Networks (UWSNs) provide new opportunities to observe and predict the behavior of aquatic environments. In some applications like target tracking or disaster prevention, sensed data is meaningless without location information. In this paper, we propose a novel 3D centralized, localization scheme for mobile underwater wireless sensor network, named Reverse Localization Scheme or RLS in short. RLS is an event-driven localization method triggered by detector sensors for launching localization process. RLS is suitable for surveillance applications that require very fast reactions to events and could report the location of the occurrence. In this method, mobile sensor nodes report the event toward the surface anchors as soon as they detect it. They do not require waiting to receive location information from anchors. Simulation results confirm that the proposed scheme improves the energy efficiency and reduces significantly localization response time with a proper level of accuracy in terms of mobility model of water currents. Major contributions of this method lie on reducing the numbers of message exchange for localization, saving the energy and decreasing the average localization response time. PMID:22666034

  16. A Network Coding Based Hybrid ARQ Protocol for Underwater Acoustic Sensor Networks

    PubMed Central

    Wang, Hao; Wang, Shilian; Zhang, Eryang; Zou, Jianbin

    2016-01-01

    Underwater Acoustic Sensor Networks (UASNs) have attracted increasing interest in recent years due to their extensive commercial and military applications. However, the harsh underwater channel causes many challenges for the design of reliable underwater data transport protocol. In this paper, we propose an energy efficient data transport protocol based on network coding and hybrid automatic repeat request (NCHARQ) to ensure reliability, efficiency and availability in UASNs. Moreover, an adaptive window length estimation algorithm is designed to optimize the throughput and energy consumption tradeoff. The algorithm can adaptively change the code rate and can be insensitive to the environment change. Extensive simulations and analysis show that NCHARQ significantly reduces energy consumption with short end-to-end delay. PMID:27618044

  17. A Network Coding Based Hybrid ARQ Protocol for Underwater Acoustic Sensor Networks.

    PubMed

    Wang, Hao; Wang, Shilian; Zhang, Eryang; Zou, Jianbin

    2016-01-01

    Underwater Acoustic Sensor Networks (UASNs) have attracted increasing interest in recent years due to their extensive commercial and military applications. However, the harsh underwater channel causes many challenges for the design of reliable underwater data transport protocol. In this paper, we propose an energy efficient data transport protocol based on network coding and hybrid automatic repeat request (NCHARQ) to ensure reliability, efficiency and availability in UASNs. Moreover, an adaptive window length estimation algorithm is designed to optimize the throughput and energy consumption tradeoff. The algorithm can adaptively change the code rate and can be insensitive to the environment change. Extensive simulations and analysis show that NCHARQ significantly reduces energy consumption with short end-to-end delay. PMID:27618044

  18. A Network Coding Based Hybrid ARQ Protocol for Underwater Acoustic Sensor Networks.

    PubMed

    Wang, Hao; Wang, Shilian; Zhang, Eryang; Zou, Jianbin

    2016-09-07

    Underwater Acoustic Sensor Networks (UASNs) have attracted increasing interest in recent years due to their extensive commercial and military applications. However, the harsh underwater channel causes many challenges for the design of reliable underwater data transport protocol. In this paper, we propose an energy efficient data transport protocol based on network coding and hybrid automatic repeat request (NCHARQ) to ensure reliability, efficiency and availability in UASNs. Moreover, an adaptive window length estimation algorithm is designed to optimize the throughput and energy consumption tradeoff. The algorithm can adaptively change the code rate and can be insensitive to the environment change. Extensive simulations and analysis show that NCHARQ significantly reduces energy consumption with short end-to-end delay.

  19. A micro-Doppler sonar for acoustic surveillance in sensor networks

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaonian

    Wireless sensor networks have been employed in a wide variety of applications, despite the limited energy and communication resources at each sensor node. Low power custom VLSI chips implementing passive acoustic sensing algorithms have been successfully integrated into an acoustic surveillance unit and demonstrated for detection and location of sound sources. In this dissertation, I explore active and passive acoustic sensing techniques, signal processing and classification algorithms for detection and classification in a multinodal sensor network environment. I will present the design and characterization of a continuous-wave micro-Doppler sonar to image objects with articulated moving components. As an example application for this system, we use it to image gaits of humans and four-legged animals. I will present the micro-Doppler gait signatures of a walking person, a dog and a horse. I will discuss the resolution and range of this micro-Doppler sonar and use experimental results to support the theoretical analyses. In order to reduce the data rate and make the system amenable to wireless sensor networks, I will present a second micro-Doppler sonar that uses bandpass sampling for data acquisition. Speech recognition algorithms are explored for biometric identifications from one's gait, and I will present and compare the classification performance of the two systems. The acoustic micro-Doppler sonar design and biometric identification results are the first in the field as the previous work used either video camera or microwave technology. I will also review bearing estimation algorithms and present results of applying these algorithms for bearing estimation and tracking of moving vehicles. Another major source of the power consumption at each sensor node is the wireless interface. To address the need of low power communications in a wireless sensor network, I will also discuss the design and implementation of ultra wideband transmitters in a three dimensional

  20. An adaptive OFDMA-based MAC protocol for underwater acoustic wireless sensor networks.

    PubMed

    Khalil, Issa M; Gadallah, Yasser; Hayajneh, Mohammad; Khreishah, Abdallah

    2012-01-01

    Underwater acoustic wireless sensor networks (UAWSNs) have many applications across various civilian and military domains. However, they suffer from the limited available bandwidth of acoustic signals and harsh underwater conditions. In this work, we present an Orthogonal Frequency Division Multiple Access (OFDMA)-based Media Access Control (MAC) protocol that is configurable to suit the operating requirements of the underwater sensor network. The protocol has three modes of operation, namely random, equal opportunity and energy-conscious modes of operation. Our MAC design approach exploits the multi-path characteristics of a fading acoustic channel to convert it into parallel independent acoustic sub-channels that undergo flat fading. Communication between node pairs within the network is done using subsets of these sub-channels, depending on the configurations of the active mode of operation. Thus, the available limited bandwidth gets fully utilized while completely avoiding interference. We derive the mathematical model for optimal power loading and subcarrier selection, which is used as basis for all modes of operation of the protocol. We also conduct many simulation experiments to evaluate and compare our protocol with other Code Division Multiple Access (CDMA)-based MAC protocols.

  1. An Adaptive OFDMA-Based MAC Protocol for Underwater Acoustic Wireless Sensor Networks

    PubMed Central

    Khalil, Issa M.; Gadallah, Yasser; Hayajneh, Mohammad; Khreishah, Abdallah

    2012-01-01

    Underwater acoustic wireless sensor networks (UAWSNs) have many applications across various civilian and military domains. However, they suffer from the limited available bandwidth of acoustic signals and harsh underwater conditions. In this work, we present an Orthogonal Frequency Division Multiple Access (OFDMA)-based Media Access Control (MAC) protocol that is configurable to suit the operating requirements of the underwater sensor network. The protocol has three modes of operation, namely random, equal opportunity and energy-conscious modes of operation. Our MAC design approach exploits the multi-path characteristics of a fading acoustic channel to convert it into parallel independent acoustic sub-channels that undergo flat fading. Communication between node pairs within the network is done using subsets of these sub-channels, depending on the configurations of the active mode of operation. Thus, the available limited bandwidth gets fully utilized while completely avoiding interference. We derive the mathematical model for optimal power loading and subcarrier selection, which is used as basis for all modes of operation of the protocol. We also conduct many simulation experiments to evaluate and compare our protocol with other Code Division Multiple Access (CDMA)-based MAC protocols. PMID:23012517

  2. AURP: an AUV-aided underwater routing protocol for underwater acoustic sensor networks.

    PubMed

    Yoon, Seokhoon; Azad, Abul K; Oh, Hoon; Kim, Sunghwan

    2012-01-01

    Deploying a multi-hop underwater acoustic sensor network (UASN) in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address those challenges and achieve the objectives of maximization of data delivery ratio and minimization of energy consumption of underwater sensor nodes, this paper proposes a new underwater routing scheme, namely AURP (AUV-aided underwater routing protocol), which uses not only heterogeneous acoustic communication channels but also controlled mobility of multiple autonomous underwater vehicles (AUVs). In AURP, the total data transmissions are minimized by using AUVs as relay nodes, which collect sensed data from gateway nodes and then forward to the sink. Moreover, controlled mobility of AUVs makes it possible to apply a short-range high data rate underwater channel for transmissions of a large amount of data. To the best to our knowledge, this work is the first attempt to employ multiple AUVs as relay nodes in a multi-hop UASN to improve the network performance in terms of data delivery ratio and energy consumption. Simulations, which are incorporated with a realistic underwater acoustic communication channel model, are carried out to evaluate the performance of the proposed scheme, and the results indicate that a high delivery ratio and low energy consumption can be achieved. PMID:22438740

  3. AURP: An AUV-Aided Underwater Routing Protocol for Underwater Acoustic Sensor Networks

    PubMed Central

    Yoon, Seokhoon; Azad, Abul K.; Oh, Hoon; Kim, Sunghwan

    2012-01-01

    Deploying a multi-hop underwater acoustic sensor network (UASN) in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address those challenges and achieve the objectives of maximization of data delivery ratio and minimization of energy consumption of underwater sensor nodes, this paper proposes a new underwater routing scheme, namely AURP (AUV-aided underwater routing protocol), which uses not only heterogeneous acoustic communication channels but also controlled mobility of multiple autonomous underwater vehicles (AUVs). In AURP, the total data transmissions are minimized by using AUVs as relay nodes, which collect sensed data from gateway nodes and then forward to the sink. Moreover, controlled mobility of AUVs makes it possible to apply a short-range high data rate underwater channel for transmissions of a large amount of data. To the best to our knowledge, this work is the first attempt to employ multiple AUVs as relay nodes in a multi-hop UASN to improve the network performance in terms of data delivery ratio and energy consumption. Simulations, which are incorporated with a realistic underwater acoustic communication channel model, are carried out to evaluate the performance of the proposed scheme, and the results indicate that a high delivery ratio and low energy consumption can be achieved. PMID:22438740

  4. AURP: an AUV-aided underwater routing protocol for underwater acoustic sensor networks.

    PubMed

    Yoon, Seokhoon; Azad, Abul K; Oh, Hoon; Kim, Sunghwan

    2012-01-01

    Deploying a multi-hop underwater acoustic sensor network (UASN) in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address those challenges and achieve the objectives of maximization of data delivery ratio and minimization of energy consumption of underwater sensor nodes, this paper proposes a new underwater routing scheme, namely AURP (AUV-aided underwater routing protocol), which uses not only heterogeneous acoustic communication channels but also controlled mobility of multiple autonomous underwater vehicles (AUVs). In AURP, the total data transmissions are minimized by using AUVs as relay nodes, which collect sensed data from gateway nodes and then forward to the sink. Moreover, controlled mobility of AUVs makes it possible to apply a short-range high data rate underwater channel for transmissions of a large amount of data. To the best to our knowledge, this work is the first attempt to employ multiple AUVs as relay nodes in a multi-hop UASN to improve the network performance in terms of data delivery ratio and energy consumption. Simulations, which are incorporated with a realistic underwater acoustic communication channel model, are carried out to evaluate the performance of the proposed scheme, and the results indicate that a high delivery ratio and low energy consumption can be achieved.

  5. Monitoring Anthropogenic Ocean Sound from Shipping Using an Acoustic Sensor Network and a Compressive Sensing Approach.

    PubMed

    Harris, Peter; Philip, Rachel; Robinson, Stephen; Wang, Lian

    2016-03-22

    Monitoring ocean acoustic noise has been the subject of considerable recent study, motivated by the desire to assess the impact of anthropogenic noise on marine life. A combination of measuring ocean sound using an acoustic sensor network and modelling sources of sound and sound propagation has been proposed as an approach to estimating the acoustic noise map within a region of interest. However, strategies for developing a monitoring network are not well established. In this paper, considerations for designing a network are investigated using a simulated scenario based on the measurement of sound from ships in a shipping lane. Using models for the sources of the sound and for sound propagation, a noise map is calculated and measurements of the noise map by a sensor network within the region of interest are simulated. A compressive sensing algorithm, which exploits the sparsity of the representation of the noise map in terms of the sources, is used to estimate the locations and levels of the sources and thence the entire noise map within the region of interest. It is shown that although the spatial resolution to which the sound sources can be identified is generally limited, estimates of aggregated measures of the noise map can be obtained that are more reliable compared with those provided by other approaches.

  6. A hybrid wireless sensor network for acoustic emission testing in SHM

    NASA Astrophysics Data System (ADS)

    Grosse, Christian; McLaskey, Greg; Bachmaier, Sebastian; Glaser, Steven D.; Krüger, Markus

    2008-03-01

    Acoustic emission techniques (AET) have a lot of potential in structural health monitoring for example to detect cracks or wire breaks. However, the number of actual applications of conventional wired AET on structures is limited due to the expensive and time consuming installation process. Wires are also vulnerable to damage and vandalisms. Wireless systems instead are easy to be attached to structures, scalable and cost efficient. A hybrid sensor network system is presented being able to use any kind of commercial available AE sensor controlled by a sensor node. In addition micro-electro-mechanical systems (MEMS) can be used as sensors measuring for example temperature, humidity or strain. The network combines multi-hop data transmission techniques with efficient data pre-processing in the nodes. The data processing of different sensor data prior to energy consuming radio transmission is an important feature to enable wireless networking. Moreover, clusters of sensor nodes are formed within the network to compare the pre-processed data. In this way it is possible to limit the data transfer through the network and to the sink as well as the amount of data to be reviewed by the owner. In particular, this paper deals with the optimization of the network to record different type of data including AE data. The basic principles of a wireless monitoring system equipped with MEMS sensors is presented along with a first prototype able to record temperature, moisture, strain and other data continuously. The extraction of relevant information out of the recorded AE data in terms of array data processing is presented in a second paper by McLaskey et al. in these proceedings. Using these two techniques, monitoring of large structures in civil engineering becomes very efficient.

  7. Energy balanced strategies for maximizing the lifetime of sparsely deployed underwater acoustic sensor networks.

    PubMed

    Luo, Hanjiang; Guo, Zhongwen; Wu, Kaishun; Hong, Feng; Feng, Yuan

    2009-01-01

    Underwater acoustic sensor networks (UWA-SNs) are envisioned to perform monitoring tasks over the large portion of the world covered by oceans. Due to economics and the large area of the ocean, UWA-SNs are mainly sparsely deployed networks nowadays. The limited battery resources is a big challenge for the deployment of such long-term sensor networks. Unbalanced battery energy consumption will lead to early energy depletion of nodes, which partitions the whole networks and impairs the integrity of the monitoring datasets or even results in the collapse of the entire networks. On the contrary, balanced energy dissipation of nodes can prolong the lifetime of such networks. In this paper, we focus on the energy balance dissipation problem of two types of sparsely deployed UWA-SNs: underwater moored monitoring systems and sparsely deployed two-dimensional UWA-SNs. We first analyze the reasons of unbalanced energy consumption in such networks, then we propose two energy balanced strategies to maximize the lifetime of networks both in shallow and deep water. Finally, we evaluate our methods by simulations and the results show that the two strategies can achieve balanced energy consumption per node while at the same time prolong the networks lifetime.

  8. An Enhanced Energy Balanced Data Transmission Protocol for Underwater Acoustic Sensor Networks

    PubMed Central

    Javaid, Nadeem; Shah, Mehreen; Ahmad, Ashfaq; Imran, Muhammad; Khan, Majid Iqbal; Vasilakos, Athanasios V.

    2016-01-01

    This paper presents two new energy balanced routing protocols for Underwater Acoustic Sensor Networks (UASNs); Efficient and Balanced Energy consumption Technique (EBET) and Enhanced EBET (EEBET). The first proposed protocol avoids direct transmission over long distance to save sufficient amount of energy consumed in the routing process. The second protocol overcomes the deficiencies in both Balanced Transmission Mechanism (BTM) and EBET techniques. EBET selects relay node on the basis of optimal distance threshold which leads to network lifetime prolongation. The initial energy of each sensor node is divided into energy levels for balanced energy consumption. Selection of high energy level node within transmission range avoids long distance direct data transmission. The EEBET incorporates depth threshold to minimize the number of hops between source node and sink while eradicating backward data transmissions. The EBET technique balances energy consumption within successive ring sectors, while, EEBET balances energy consumption of the entire network. In EEBET, optimum number of energy levels are also calculated to further enhance the network lifetime. Effectiveness of the proposed schemes is validated through simulations where these are compared with two existing routing protocols in terms of network lifetime, transmission loss, and throughput. The simulations are conducted under different network radii and varied number of nodes. PMID:27070605

  9. An Enhanced Energy Balanced Data Transmission Protocol for Underwater Acoustic Sensor Networks.

    PubMed

    Javaid, Nadeem; Shah, Mehreen; Ahmad, Ashfaq; Imran, Muhammad; Khan, Majid Iqbal; Vasilakos, Athanasios V

    2016-01-01

    This paper presents two new energy balanced routing protocols for Underwater Acoustic Sensor Networks (UASNs); Efficient and Balanced Energy consumption Technique (EBET) and Enhanced EBET (EEBET). The first proposed protocol avoids direct transmission over long distance to save sufficient amount of energy consumed in the routing process. The second protocol overcomes the deficiencies in both Balanced Transmission Mechanism (BTM) and EBET techniques. EBET selects relay node on the basis of optimal distance threshold which leads to network lifetime prolongation. The initial energy of each sensor node is divided into energy levels for balanced energy consumption. Selection of high energy level node within transmission range avoids long distance direct data transmission. The EEBET incorporates depth threshold to minimize the number of hops between source node and sink while eradicating backward data transmissions. The EBET technique balances energy consumption within successive ring sectors, while, EEBET balances energy consumption of the entire network. In EEBET, optimum number of energy levels are also calculated to further enhance the network lifetime. Effectiveness of the proposed schemes is validated through simulations where these are compared with two existing routing protocols in terms of network lifetime, transmission loss, and throughput. The simulations are conducted under different network radii and varied number of nodes.

  10. An Enhanced Energy Balanced Data Transmission Protocol for Underwater Acoustic Sensor Networks.

    PubMed

    Javaid, Nadeem; Shah, Mehreen; Ahmad, Ashfaq; Imran, Muhammad; Khan, Majid Iqbal; Vasilakos, Athanasios V

    2016-01-01

    This paper presents two new energy balanced routing protocols for Underwater Acoustic Sensor Networks (UASNs); Efficient and Balanced Energy consumption Technique (EBET) and Enhanced EBET (EEBET). The first proposed protocol avoids direct transmission over long distance to save sufficient amount of energy consumed in the routing process. The second protocol overcomes the deficiencies in both Balanced Transmission Mechanism (BTM) and EBET techniques. EBET selects relay node on the basis of optimal distance threshold which leads to network lifetime prolongation. The initial energy of each sensor node is divided into energy levels for balanced energy consumption. Selection of high energy level node within transmission range avoids long distance direct data transmission. The EEBET incorporates depth threshold to minimize the number of hops between source node and sink while eradicating backward data transmissions. The EBET technique balances energy consumption within successive ring sectors, while, EEBET balances energy consumption of the entire network. In EEBET, optimum number of energy levels are also calculated to further enhance the network lifetime. Effectiveness of the proposed schemes is validated through simulations where these are compared with two existing routing protocols in terms of network lifetime, transmission loss, and throughput. The simulations are conducted under different network radii and varied number of nodes. PMID:27070605

  11. Acoustic Source Localization via Distributed Sensor Networks using Tera-scale Optical-Core Devices

    SciTech Connect

    Imam, Neena; Barhen, Jacob; Wardlaw, Michael

    2008-01-01

    For real-time acoustic source localization applications, one of the primary challenges is the considerable growth in computational complexity associated with the emergence of ever larger, active or passive, distributed sensor networks. The complexity of the calculations needed to achieve accurate source localization increases dramatically with the size of sensor arrays, resulting in substantial growth of computational requirements that cannot be met with standard hardware. One option to meet this challenge builds upon the emergence of digital optical-core devices. The objective of this work was to explore the implementation of key building block algorithms used in underwater source localization on an optical-core digital processing platform recently introduced by Lenslet Inc. They investigate key concepts of threat-detection algorithms such as Time Difference Of Arrival (TDOA) estimation via sensor data correlation in the time domain with the purpose of implementation on the optical-core processor. they illustrate their results with the aid of numerical simulation and actual optical hardware runs. The major accomplishments of this research, in terms of computational speedup and numerical accurcy achieved via the deployment of optical processing technology, should be of substantial interest to the acoustic signal processing community.

  12. Maximization of the supportable number of sensors in QoS-aware cluster-based underwater acoustic sensor networks.

    PubMed

    Nguyen, Thi-Tham; Le, Duc Van; Yoon, Seokhoon

    2014-01-01

    This paper proposes a practical low-complexity MAC (medium access control) scheme for quality of service (QoS)-aware and cluster-based underwater acoustic sensor networks (UASN), in which the provision of differentiated QoS is required. In such a network, underwater sensors (U-sensor) in a cluster are divided into several classes, each of which has a different QoS requirement. The major problem considered in this paper is the maximization of the number of nodes that a cluster can accommodate while still providing the required QoS for each class in terms of the PDR (packet delivery ratio). In order to address the problem, we first estimate the packet delivery probability (PDP) and use it to formulate an optimization problem to determine the optimal value of the maximum packet retransmissions for each QoS class. The custom greedy and interior-point algorithms are used to find the optimal solutions, which are verified by extensive simulations. The simulation results show that, by solving the proposed optimization problem, the supportable number of underwater sensor nodes can be maximized while satisfying the QoS requirements for each class.

  13. Secure cooperation of autonomous mobile sensors using an underwater acoustic network.

    PubMed

    Caiti, Andrea; Calabrò, Vincenzo; Dini, Gianluca; Lo Duca, Angelica; Munafò, Andrea

    2012-01-01

    Methodologies and algorithms are presented for the secure cooperation of a team of autonomous mobile underwater sensors, connected through an acoustic communication network, within surveillance and patrolling applications. In particular, the work proposes a cooperative algorithm in which the mobile underwater sensors (installed on Autonomous Underwater Vehicles-AUVs) respond to simple local rules based on the available information to perform the mission and maintain the communication link with the network (behavioral approach). The algorithm is intrinsically robust: with loss of communication among the vehicles the coverage performance (i.e., the mission goal) is degraded but not lost. The ensuing form of graceful degradation provides also a reactive measure against Denial of Service. The cooperative algorithm relies on the fact that the available information from the other sensors, though not necessarily complete, is trustworthy. To ensure trustworthiness, a security suite has been designed, specifically oriented to the underwater scenario, and in particular with the goal of reducing the communication overhead introduced by security in terms of number and size of messages. The paper gives implementation details on the integration between the security suite and the cooperative algorithm and provides statistics on the performance of the system as collected during the UAN project sea trial held in Trondheim, Norway, in May 2011.

  14. Secure Cooperation of Autonomous Mobile Sensors Using an Underwater Acoustic Network

    PubMed Central

    Caiti, Andrea; Calabrò, Vincenzo; Dini, Gianluca; Duca, Angelica Lo; Munafò, Andrea

    2012-01-01

    Methodologies and algorithms are presented for the secure cooperation of a team of autonomous mobile underwater sensors, connected through an acoustic communication network, within surveillance and patrolling applications. In particular, the work proposes a cooperative algorithm in which the mobile underwater sensors (installed on Autonomous Underwater Vehicles—AUVs) respond to simple local rules based on the available information to perform the mission and maintain the communication link with the network (behavioral approach). The algorithm is intrinsically robust: with loss of communication among the vehicles the coverage performance (i.e., the mission goal) is degraded but not lost. The ensuing form of graceful degradation provides also a reactive measure against Denial of Service. The cooperative algorithm relies on the fact that the available information from the other sensors, though not necessarily complete, is trustworthy. To ensure trustworthiness, a security suite has been designed, specifically oriented to the underwater scenario, and in particular with the goal of reducing the communication overhead introduced by security in terms of number and size of messages. The paper gives implementation details on the integration between the security suite and the cooperative algorithm and provides statistics on the performance of the system as collected during the UAN project sea trial held in Trondheim, Norway, in May 2011. PMID:22438748

  15. Secure cooperation of autonomous mobile sensors using an underwater acoustic network.

    PubMed

    Caiti, Andrea; Calabrò, Vincenzo; Dini, Gianluca; Lo Duca, Angelica; Munafò, Andrea

    2012-01-01

    Methodologies and algorithms are presented for the secure cooperation of a team of autonomous mobile underwater sensors, connected through an acoustic communication network, within surveillance and patrolling applications. In particular, the work proposes a cooperative algorithm in which the mobile underwater sensors (installed on Autonomous Underwater Vehicles-AUVs) respond to simple local rules based on the available information to perform the mission and maintain the communication link with the network (behavioral approach). The algorithm is intrinsically robust: with loss of communication among the vehicles the coverage performance (i.e., the mission goal) is degraded but not lost. The ensuing form of graceful degradation provides also a reactive measure against Denial of Service. The cooperative algorithm relies on the fact that the available information from the other sensors, though not necessarily complete, is trustworthy. To ensure trustworthiness, a security suite has been designed, specifically oriented to the underwater scenario, and in particular with the goal of reducing the communication overhead introduced by security in terms of number and size of messages. The paper gives implementation details on the integration between the security suite and the cooperative algorithm and provides statistics on the performance of the system as collected during the UAN project sea trial held in Trondheim, Norway, in May 2011. PMID:22438748

  16. Throughput and Energy Efficiency of a Cooperative Hybrid ARQ Protocol for Underwater Acoustic Sensor Networks

    PubMed Central

    Ghosh, Arindam; Lee, Jae-Won; Cho, Ho-Shin

    2013-01-01

    Due to its efficiency, reliability and better channel and resource utilization, cooperative transmission technologies have been attractive options in underwater as well as terrestrial sensor networks. Their performance can be further improved if merged with forward error correction (FEC) techniques. In this paper, we propose and analyze a retransmission protocol named Cooperative-Hybrid Automatic Repeat reQuest (C-HARQ) for underwater acoustic sensor networks, which exploits both the reliability of cooperative ARQ (CARQ) and the efficiency of incremental redundancy-hybrid ARQ (IR-HARQ) using rate-compatible punctured convolution (RCPC) codes. Extensive Monte Carlo simulations are performed to investigate the performance of the protocol, in terms of both throughput and energy efficiency. The results clearly reveal the enhancement in performance achieved by the C-HARQ protocol, which outperforms both CARQ and conventional stop and wait ARQ (S&W ARQ). Further, using computer simulations, optimum values of various network parameters are estimated so as to extract the best performance out of the C-HARQ protocol. PMID:24217359

  17. Throughput and energy efficiency of a cooperative hybrid ARQ protocol for underwater acoustic sensor networks.

    PubMed

    Ghosh, Arindam; Lee, Jae-Won; Cho, Ho-Shin

    2013-11-08

    Due to its efficiency, reliability and better channel and resource utilization, cooperative transmission technologies have been attractive options in underwater as well as terrestrial sensor networks. Their performance can be further improved if merged with forward error correction (FEC) techniques. In this paper, we propose and analyze a retransmission protocol named Cooperative-Hybrid Automatic Repeat reQuest (C-HARQ) for underwater acoustic sensor networks, which exploits both the reliability of cooperative ARQ (CARQ) and the efficiency of incremental redundancy-hybrid ARQ (IR-HARQ) using rate-compatible punctured convolution (RCPC) codes. Extensive Monte Carlo simulations are performed to investigate the performance of the protocol, in terms of both throughput and energy efficiency. The results clearly reveal the enhancement in performance achieved by the C-HARQ protocol, which outperforms both CARQ and conventional stop and wait ARQ (S&W ARQ). Further, using computer simulations, optimum values of various network parameters are estimated so as to extract the best performance out of the C-HARQ protocol.

  18. An Amplitude-Based Estimation Method for International Space Station (ISS) Leak Detection and Localization Using Acoustic Sensor Networks

    NASA Technical Reports Server (NTRS)

    Tian, Jialin; Madaras, Eric I.

    2009-01-01

    The development of a robust and efficient leak detection and localization system within a space station environment presents a unique challenge. A plausible approach includes the implementation of an acoustic sensor network system that can successfully detect the presence of a leak and determine the location of the leak source. Traditional acoustic detection and localization schemes rely on the phase and amplitude information collected by the sensor array system. Furthermore, the acoustic source signals are assumed to be airborne and far-field. Likewise, there are similar applications in sonar. In solids, there are specialized methods for locating events that are used in geology and in acoustic emission testing that involve sensor arrays and depend on a discernable phase front to the received signal. These methods are ineffective if applied to a sensor detection system within the space station environment. In the case of acoustic signal location, there are significant baffling and structural impediments to the sound path and the source could be in the near-field of a sensor in this particular setting.

  19. Sound-maps of environmentally sensitive areas constructed from Wireless Acoustic Sensors Network data

    NASA Astrophysics Data System (ADS)

    Michailidis, E. T.; Liaperdos, J.; Tatlas, N.-A.; Potirakis, S. M.; Rangoussi, M.

    2016-03-01

    “E-SOUNDMAPS” is a distributed microelectronic system for the sound/acoustic monitoring of areas of environmental interest that is based on an appropriately designed wireless acoustic sensor network (WASN). It involves the automated generation of multi-level sound-maps for environmental assessment of areas of interest. This paper focuses on the method and the software application for the construction of sound-maps, which is developed as part of the integrated “E-SOUNDMAPS” system. The software application periodically produces geographically-referenced, accurate environmental sound information, based on real- field measurement data, and integrates them in the geographic map of the area of interest in a concise and comprehensive manner. Following the field recording of sound and the hierarchical recognition/classification of sound events and corresponding sources, the obtained sound sources characterization tags feed the specific software application. The output is a multilevel soundmap, constructed on the basis of the data and published electronically on the Web, for human inspection and assessment. All necessary steps for handling, archiving, monitoring, visualization and retrieval of sound data are also presented.

  20. Lightweight filter architecture for energy efficient mobile vehicle localization based on a distributed acoustic sensor network.

    PubMed

    Kim, Keonwook

    2013-08-23

    The generic properties of an acoustic signal provide numerous benefits for localization by applying energy-based methods over a deployed wireless sensor network (WSN). However, the signal generated by a stationary target utilizes a significant amount of bandwidth and power in the system without providing further position information. For vehicle localization, this paper proposes a novel proximity velocity vector estimator (PVVE) node architecture in order to capture the energy from a moving vehicle and reject the signal from motionless automobiles around the WSN node. A cascade structure between analog envelope detector and digital exponential smoothing filter presents the velocity vector-sensitive output with low analog circuit and digital computation complexity. The optimal parameters in the exponential smoothing filter are obtained by analytical and mathematical methods for maximum variation over the vehicle speed. For stationary targets, the derived simulation based on the acoustic field parameters demonstrates that the system significantly reduces the communication requirements with low complexity and can be expected to extend the operation time considerably.

  1. Lightweight Filter Architecture for Energy Efficient Mobile Vehicle Localization Based on a Distributed Acoustic Sensor Network

    PubMed Central

    Kim, Keonwook

    2013-01-01

    The generic properties of an acoustic signal provide numerous benefits for localization by applying energy-based methods over a deployed wireless sensor network (WSN). However, the signal generated by a stationary target utilizes a significant amount of bandwidth and power in the system without providing further position information. For vehicle localization, this paper proposes a novel proximity velocity vector estimator (PVVE) node architecture in order to capture the energy from a moving vehicle and reject the signal from motionless automobiles around the WSN node. A cascade structure between analog envelope detector and digital exponential smoothing filter presents the velocity vector-sensitive output with low analog circuit and digital computation complexity. The optimal parameters in the exponential smoothing filter are obtained by analytical and mathematical methods for maximum variation over the vehicle speed. For stationary targets, the derived simulation based on the acoustic field parameters demonstrates that the system significantly reduces the communication requirements with low complexity and can be expected to extend the operation time considerably. PMID:23979482

  2. Acoustic measurement of sediment dynamics in the coastal zones using wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Sudhakaran, A., II; Paramasivam, A.; Seshachalam, S.; A, C.

    2014-12-01

    Analyzing of the impact of constructive or low energy waves and deconstructive or high energy waves in the ocean are very much significant since they deform the geometry of seashore. The deformation may lead to productive result and also to the end of deteriorate damage. Constructive waves results deposition of sediment which widens the beach where as deconstructive waves results erosion which narrows the beach. Validation of historic sediment transportation and prediction of the direction of movement of seashore is essential to prevent unrecoverable damages by incorporating precautionary measurements to identify the factors that influence sediment transportation if feasible. The objective of this study is to propose a more reliable and energy efficient Information and communication system to model the Coastal Sediment Dynamics. Various factors influencing the sediment drift at a particular region is identified. Consequence of source depth and frequency dependencies of spread pattern in the presence of sediments is modeled. Property of source depth and frequency on sensitivity to values of model parameters are determined. Fundamental physical reasons for these sediment interaction effects are given. Shallow to deep water and internal and external wave model of ocean is obtained intended to get acoustic data assimilation (ADA). Signal processing algorithms are used over the observed data to form a full field acoustic propagation model and construct sound speed profile (SSP). The inversions of data due to uncertainties at various depths are compared. The impact of sediment drift over acoustic data is identified. An energy efficient multipath routing scheme Wireless sensor networks (WSN) is deployed for the well-organized communication of data. The WSN is designed considering increased life time, decreased power consumption, free of threats and attacks. The practical data obtained from the efficient system to model the ocean sediment dynamics are evaluated with remote

  3. A hybrid path-oriented code assignment CDMA-based MAC protocol for underwater acoustic sensor networks.

    PubMed

    Chen, Huifang; Fan, Guangyu; Xie, Lei; Cui, Jun-Hong

    2013-11-04

    Due to the characteristics of underwater acoustic channel, media access control (MAC) protocols designed for underwater acoustic sensor networks (UWASNs) are quite different from those for terrestrial wireless sensor networks. Moreover, in a sink-oriented network with event information generation in a sensor field and message forwarding to the sink hop-by-hop, the sensors near the sink have to transmit more packets than those far from the sink, and then a funneling effect occurs, which leads to packet congestion, collisions and losses, especially in UWASNs with long propagation delays. An improved CDMA-based MAC protocol, named path-oriented code assignment (POCA) CDMA MAC (POCA-CDMA-MAC), is proposed for UWASNs in this paper. In the proposed MAC protocol, both the round-robin method and CDMA technology are adopted to make the sink receive packets from multiple paths simultaneously. Since the number of paths for information gathering is much less than that of nodes, the length of the spreading code used in the POCA-CDMA-MAC protocol is shorter greatly than that used in the CDMA-based protocols with transmitter-oriented code assignment (TOCA) or receiver-oriented code assignment (ROCA). Simulation results show that the proposed POCA-CDMA-MAC protocol achieves a higher network throughput and a lower end-to-end delay compared to other CDMA-based MAC protocols.

  4. A Hybrid Path-Oriented Code Assignment CDMA-Based MAC Protocol for Underwater Acoustic Sensor Networks

    PubMed Central

    Chen, Huifang; Fan, Guangyu; Xie, Lei; Cui, Jun-Hong

    2013-01-01

    Due to the characteristics of underwater acoustic channel, media access control (MAC) protocols designed for underwater acoustic sensor networks (UWASNs) are quite different from those for terrestrial wireless sensor networks. Moreover, in a sink-oriented network with event information generation in a sensor field and message forwarding to the sink hop-by-hop, the sensors near the sink have to transmit more packets than those far from the sink, and then a funneling effect occurs, which leads to packet congestion, collisions and losses, especially in UWASNs with long propagation delays. An improved CDMA-based MAC protocol, named path-oriented code assignment (POCA) CDMA MAC (POCA-CDMA-MAC), is proposed for UWASNs in this paper. In the proposed MAC protocol, both the round-robin method and CDMA technology are adopted to make the sink receive packets from multiple paths simultaneously. Since the number of paths for information gathering is much less than that of nodes, the length of the spreading code used in the POCA-CDMA-MAC protocol is shorter greatly than that used in the CDMA-based protocols with transmitter-oriented code assignment (TOCA) or receiver-oriented code assignment (ROCA). Simulation results show that the proposed POCA-CDMA-MAC protocol achieves a higher network throughput and a lower end-to-end delay compared to other CDMA-based MAC protocols. PMID:24193100

  5. Underwater Wireless Sensor Networks: how do acoustic propagation models impact the performance of higher-level protocols?

    PubMed

    Llor, Jesús; Malumbres, Manuel P

    2012-01-01

    Several Medium Access Control (MAC) and routing protocols have been developed in the last years for Underwater Wireless Sensor Networks (UWSNs). One of the main difficulties to compare and validate the performance of different proposals is the lack of a common standard to model the acoustic propagation in the underwater environment. In this paper we analyze the evolution of underwater acoustic prediction models from a simple approach to more detailed and accurate models. Then, different high layer network protocols are tested with different acoustic propagation models in order to determine the influence of environmental parameters on the obtained results. After several experiments, we can conclude that higher-level protocols are sensitive to both: (a) physical layer parameters related to the network scenario and (b) the acoustic propagation model. Conditions like ocean surface activity, scenario location, bathymetry or floor sediment composition, may change the signal propagation behavior. So, when designing network architectures for UWSNs, the role of the physical layer should be seriously taken into account in order to assert that the obtained simulation results will be close to the ones obtained in real network scenarios.

  6. Color filtering localization for three-dimensional underwater acoustic sensor networks.

    PubMed

    Liu, Zhihua; Gao, Han; Wang, Wuling; Chang, Shuai; Chen, Jiaxing

    2015-01-01

    Accurate localization of mobile nodes has been an important and fundamental problem in underwater acoustic sensor networks (UASNs). The detection information returned from a mobile node is meaningful only if its location is known. In this paper, we propose two localization algorithms based on color filtering technology called PCFL and ACFL. PCFL and ACFL aim at collaboratively accomplishing accurate localization of underwater mobile nodes with minimum energy expenditure. They both adopt the overlapping signal region of task anchors which can communicate with the mobile node directly as the current sampling area. PCFL employs the projected distances between each of the task projections and the mobile node, while ACFL adopts the direct distance between each of the task anchors and the mobile node. The proportion factor of distance is also proposed to weight the RGB values. By comparing the nearness degrees of the RGB sequences between the samples and the mobile node, samples can be filtered out. The normalized nearness degrees are considered as the weighted standards to calculate the coordinates of the mobile nodes. The simulation results show that the proposed methods have excellent localization performance and can localize the mobile node in a timely way. The average localization error of PCFL is decreased by about 30.4% compared to the AFLA method.

  7. Color Filtering Localization for Three-Dimensional Underwater Acoustic Sensor Networks

    PubMed Central

    Liu, Zhihua; Gao, Han; Wang, Wuling; Chang, Shuai; Chen, Jiaxing

    2015-01-01

    Accurate localization of mobile nodes has been an important and fundamental problem in underwater acoustic sensor networks (UASNs). The detection information returned from a mobile node is meaningful only if its location is known. In this paper, we propose two localization algorithms based on color filtering technology called PCFL and ACFL. PCFL and ACFL aim at collaboratively accomplishing accurate localization of underwater mobile nodes with minimum energy expenditure. They both adopt the overlapping signal region of task anchors which can communicate with the mobile node directly as the current sampling area. PCFL employs the projected distances between each of the task projections and the mobile node, while ACFL adopts the direct distance between each of the task anchors and the mobile node. The proportion factor of distance is also proposed to weight the RGB values. By comparing the nearness degrees of the RGB sequences between the samples and the mobile node, samples can be filtered out. The normalized nearness degrees are considered as the weighted standards to calculate the coordinates of the mobile nodes. The simulation results show that the proposed methods have excellent localization performance and can localize the mobile node in a timely way. The average localization error of PCFL is decreased by about 30.4% compared to the AFLA method. PMID:25774706

  8. Evaluation of MPEG-7-Based Audio Descriptors for Animal Voice Recognition over Wireless Acoustic Sensor Networks

    PubMed Central

    Luque, Joaquín; Larios, Diego F.; Personal, Enrique; Barbancho, Julio; León, Carlos

    2016-01-01

    Environmental audio monitoring is a huge area of interest for biologists all over the world. This is why some audio monitoring system have been proposed in the literature, which can be classified into two different approaches: acquirement and compression of all audio patterns in order to send them as raw data to a main server; or specific recognition systems based on audio patterns. The first approach presents the drawback of a high amount of information to be stored in a main server. Moreover, this information requires a considerable amount of effort to be analyzed. The second approach has the drawback of its lack of scalability when new patterns need to be detected. To overcome these limitations, this paper proposes an environmental Wireless Acoustic Sensor Network architecture focused on use of generic descriptors based on an MPEG-7 standard. These descriptors demonstrate it to be suitable to be used in the recognition of different patterns, allowing a high scalability. The proposed parameters have been tested to recognize different behaviors of two anuran species that live in Spanish natural parks; the Epidalea calamita and the Alytes obstetricans toads, demonstrating to have a high classification performance. PMID:27213375

  9. Monitoring Anthropogenic Ocean Sound from Shipping Using an Acoustic Sensor Network and a Compressive Sensing Approach †

    PubMed Central

    Harris, Peter; Philip, Rachel; Robinson, Stephen; Wang, Lian

    2016-01-01

    Monitoring ocean acoustic noise has been the subject of considerable recent study, motivated by the desire to assess the impact of anthropogenic noise on marine life. A combination of measuring ocean sound using an acoustic sensor network and modelling sources of sound and sound propagation has been proposed as an approach to estimating the acoustic noise map within a region of interest. However, strategies for developing a monitoring network are not well established. In this paper, considerations for designing a network are investigated using a simulated scenario based on the measurement of sound from ships in a shipping lane. Using models for the sources of the sound and for sound propagation, a noise map is calculated and measurements of the noise map by a sensor network within the region of interest are simulated. A compressive sensing algorithm, which exploits the sparsity of the representation of the noise map in terms of the sources, is used to estimate the locations and levels of the sources and thence the entire noise map within the region of interest. It is shown that although the spatial resolution to which the sound sources can be identified is generally limited, estimates of aggregated measures of the noise map can be obtained that are more reliable compared with those provided by other approaches. PMID:27011187

  10. An ultra-low power and flexible acoustic modem design to develop energy-efficient underwater sensor networks.

    PubMed

    Sánchez, Antonio; Blanc, Sara; Yuste, Pedro; Perles, Angel; Serrano, Juan José

    2012-01-01

    This paper is focused on the description of the physical layer of a new acoustic modem called ITACA. The modem architecture includes as a major novelty an ultra-low power asynchronous wake-up system implementation for underwater acoustic transmission that is based on a low-cost off-the-shelf RFID peripheral integrated circuit. This feature enables a reduced power dissipation of 10 μW in stand-by mode and registers very low power values during reception and transmission. The modem also incorporates clear channel assessment (CCA) to support CSMA-based medium access control (MAC) layer protocols. The design is part of a compact platform for a long-life short/medium range underwater wireless sensor network.

  11. An Ultra-Low Power and Flexible Acoustic Modem Design to Develop Energy-Efficient Underwater Sensor Networks

    PubMed Central

    Sánchez, Antonio; Blanc, Sara; Yuste, Pedro; Perles, Angel; Serrano, Juan José

    2012-01-01

    This paper is focused on the description of the physical layer of a new acoustic modem called ITACA. The modem architecture includes as a major novelty an ultra-low power asynchronous wake-up system implementation for underwater acoustic transmission that is based on a low-cost off-the-shelf RFID peripheral integrated circuit. This feature enables a reduced power dissipation of 10 μW in stand-by mode and registers very low power values during reception and transmission. The modem also incorporates clear channel assessment (CCA) to support CSMA-based medium access control (MAC) layer protocols. The design is part of a compact platform for a long-life short/medium range underwater wireless sensor network. PMID:22969324

  12. Dynamic Agent Classification and Tracking Using an Ad Hoc Mobile Acoustic Sensor Network

    NASA Astrophysics Data System (ADS)

    Friedlander, David; Griffin, Christopher; Jacobson, Noah; Phoha, Shashi; Brooks, Richard R.

    2003-12-01

    Autonomous networks of sensor platforms can be designed to interact in dynamic and noisy environments to determine the occurrence of specified transient events that define the dynamic process of interest. For example, a sensor network may be used for battlefield surveillance with the purpose of detecting, identifying, and tracking enemy activity. When the number of nodes is large, human oversight and control of low-level operations is not feasible. Coordination and self-organization of multiple autonomous nodes is necessary to maintain connectivity and sensor coverage and to combine information for better understanding the dynamics of the environment. Resource conservation requires adaptive clustering in the vicinity of the event. This paper presents methods for dynamic distributed signal processing using an ad hoc mobile network of microsensors to detect, identify, and track targets in noisy environments. They seamlessly integrate data from fixed and mobile platforms and dynamically organize platforms into clusters to process local data along the trajectory of the targets. Local analysis of sensor data is used to determine a set of target attribute values and classify the target. Sensor data from a field test in the Marine base at Twentynine Palms, Calif, was analyzed using the techniques described in this paper. The results were compared to "ground truth" data obtained from GPS receivers on the vehicles.

  13. Distributed sensor networks

    NASA Astrophysics Data System (ADS)

    Lacoss, Richard T.

    1986-09-01

    The Distributed Sensor Networks (DSN) program was aimed at developing distributed target surveillance and tracking methods for systems employing multiple spatially distributed sensors and processing resources. Such systems would be made up of sensors, data bases, and processors distributed throughout an area and interconnected by an appropriate digital data communication system. The hypothesis of the program was that through netting and distributed processing, the information from many sensors could be combined to yield effective surveillance systems. The overall concept called for a mix of sensor types as well as geographically distributed sensors. Surveillance and tracking of low-flying aircraft with ground-based acoustic and imaging sensors was used to develop and evaluate DSN concepts in the light of a specific problem. An experimental DSN testbed system was developed and has been used to test and demonstrate DSN techniques. Small arrays of microphones providing directional information were employed as acoustic sensors and visible TV cameras were used as imaging sensors in the testbed system. The primary accomplishment during this final report period was the demonstration of distributed real time tracking using both TV and acoustic sensors. Tracking was implemented as a geographically decentralized confederacy of autonomous cooperating nodes. Thus the feasibility of this organization has been established for a DSN system containing multiple sensor types as well as distributed nodes.

  14. An acoustic glucose sensor.

    PubMed

    Hu, Ruifen; Stevenson, Adrian C; Lowe, Christopher R

    2012-05-15

    In vivo glucose monitoring is required for tighter glycaemic control. This report describes a new approach to construct a miniature implantable device based on a magnetic acoustic resonance sensor (MARS). A ≈ 600-800 nm thick glucose-responsive poly(acrylamide-co-3-acrylamidophenylboronic acid) (poly(acrylamide-co-3-APB)) film was polymerised on the quartz disc (12 mm in diameter and 0.25 mm thick) of the MARS. The swelling/shrinking of the polymer film induced by the glucose binding to the phenylboronate caused changes in the resonance amplitude of the quartz disc in the MARS. A linear relationship between the response of the MARS and the glucose concentration in the range ≈ 0-15 mM was observed, with the optimum response of the MARS sensor being obtained when the polymer films contained ≈ 20 mol% 3-APB. The MARS glucose sensor also functioned under flow conditions (9 μl/min) with a response almost identical to the sensor under static or non-flow conditions. The results suggest that the MARS could offer a promising strategy for developing a small subcutaneously implanted continuous glucose monitor.

  15. Acoustic Source Localization via Time Difference of Arrival Estimation for Distributed Sensor Networks Using Tera-Scale Optical Core Devices

    DOE PAGES

    Imam, Neena; Barhen, Jacob

    2009-01-01

    For real-time acoustic source localization applications, one of the primary challenges is the considerable growth in computational complexity associated with the emergence of ever larger, active or passive, distributed sensor networks. These sensors rely heavily on battery-operated system components to achieve highly functional automation in signal and information processing. In order to keep communication requirements minimal, it is desirable to perform as much processing on the receiver platforms as possible. However, the complexity of the calculations needed to achieve accurate source localization increases dramatically with the size of sensor arrays, resulting in substantial growth of computational requirements that cannot bemore » readily met with standard hardware. One option to meet this challenge builds upon the emergence of digital optical-core devices. The objective of this work was to explore the implementation of key building block algorithms used in underwater source localization on the optical-core digital processing platform recently introduced by Lenslet Inc. This demonstration of considerably faster signal processing capability should be of substantial significance to the design and innovation of future generations of distributed sensor networks.« less

  16. Acoustic network event classification using swarm optimization

    NASA Astrophysics Data System (ADS)

    Burman, Jerry

    2013-05-01

    Classifying acoustic signals detected by distributed sensor networks is a difficult problem due to the wide variations that can occur in the transmission of terrestrial, subterranean, seismic and aerial events. An acoustic event classifier was developed that uses particle swarm optimization to perform a flexible time correlation of a sensed acoustic signature to reference data. In order to mitigate the effects from interference such as multipath, the classifier fuses signatures from multiple sensors to form a composite sensed acoustic signature and then automatically matches the composite signature with reference data. The approach can classify all types of acoustic events but is particularly well suited to explosive events such as gun shots, mortar blasts and improvised explosive devices that produce an acoustic signature having a shock wave component that is aperiodic and non-linear. The classifier was applied to field data and yielded excellent results in terms of reconstructing degraded acoustic signatures from multiple sensors and in classifying disparate acoustic events.

  17. Underwater acoustic wireless sensor networks: advances and future trends in physical, MAC and routing layers.

    PubMed

    Climent, Salvador; Sanchez, Antonio; Capella, Juan Vicente; Meratnia, Nirvana; Serrano, Juan Jose

    2014-01-01

    This survey aims to provide a comprehensive overview of the current research on underwater wireless sensor networks, focusing on the lower layers of the communication stack, and envisions future trends and challenges. It analyzes the current state-of-the-art on the physical, medium access control and routing layers. It summarizes their security threads and surveys the currently proposed studies. Current envisioned niches for further advances in underwater networks research range from efficient, low-power algorithms and modulations to intelligent, energy-aware routing and medium access control protocols. PMID:24399155

  18. Underwater acoustic wireless sensor networks: advances and future trends in physical, MAC and routing layers.

    PubMed

    Climent, Salvador; Sanchez, Antonio; Capella, Juan Vicente; Meratnia, Nirvana; Serrano, Juan Jose

    2014-01-01

    This survey aims to provide a comprehensive overview of the current research on underwater wireless sensor networks, focusing on the lower layers of the communication stack, and envisions future trends and challenges. It analyzes the current state-of-the-art on the physical, medium access control and routing layers. It summarizes their security threads and surveys the currently proposed studies. Current envisioned niches for further advances in underwater networks research range from efficient, low-power algorithms and modulations to intelligent, energy-aware routing and medium access control protocols.

  19. Underwater Acoustic Wireless Sensor Networks: Advances and Future Trends in Physical, MAC and Routing Layers

    PubMed Central

    Climent, Salvador; Sanchez, Antonio; Capella, Juan Vicente; Meratnia, Nirvana; Serrano, Juan Jose

    2014-01-01

    This survey aims to provide a comprehensive overview of the current research on underwater wireless sensor networks, focusing on the lower layers of the communication stack, and envisions future trends and challenges. It analyzes the current state-of-the-art on the physical, medium access control and routing layers. It summarizes their security threads and surveys the currently proposed studies. Current envisioned niches for further advances in underwater networks research range from efficient, low-power algorithms and modulations to intelligent, energy-aware routing and medium access control protocols. PMID:24399155

  20. Time-Efficient High-Rate Data Flooding in One-Dimensional Acoustic Underwater Sensor Networks.

    PubMed

    Kwon, Jae Kyun; Seo, Bo-Min; Yun, Kyungsu; Cho, Ho-Shin

    2015-10-30

    Because underwater communication environments have poor characteristics, such as severe attenuation, large propagation delays and narrow bandwidths, data is normally transmitted at low rates through acoustic waves. On the other hand, as high traffic has recently been required in diverse areas, high rate transmission has become necessary. In this paper, transmission/reception timing schemes that maximize the time axis use efficiency to improve the resource efficiency for high rate transmission are proposed. The excellence of the proposed scheme is identified by examining the power distributions by node, rate bounds, power levels depending on the rates and number of nodes, and network split gains through mathematical analysis and numerical results. In addition, the simulation results show that the proposed scheme outperforms the existing packet train method.

  1. Time-Efficient High-Rate Data Flooding in One-Dimensional Acoustic Underwater Sensor Networks

    PubMed Central

    Kwon, Jae Kyun; Seo, Bo-Min; Yun, Kyungsu; Cho, Ho-Shin

    2015-01-01

    Because underwater communication environments have poor characteristics, such as severe attenuation, large propagation delays and narrow bandwidths, data is normally transmitted at low rates through acoustic waves. On the other hand, as high traffic has recently been required in diverse areas, high rate transmission has become necessary. In this paper, transmission/reception timing schemes that maximize the time axis use efficiency to improve the resource efficiency for high rate transmission are proposed. The excellence of the proposed scheme is identified by examining the power distributions by node, rate bounds, power levels depending on the rates and number of nodes, and network split gains through mathematical analysis and numerical results. In addition, the simulation results show that the proposed scheme outperforms the existing packet train method. PMID:26528983

  2. Design and implementation of low complexity wake-up receiver for underwater acoustic sensor networks

    NASA Astrophysics Data System (ADS)

    Yue, Ming

    This thesis designs a low-complexity dual Pseudorandom Noise (PN) scheme for identity (ID) detection and coarse frame synchronization. The two PN sequences for a node are identical and are separated by a specified length of gap which serves as the ID of different sensor nodes. The dual PN sequences are short in length but are capable of combating severe underwater acoustic (UWA) multipath fading channels that exhibit time varying impulse responses up to 100 taps. The receiver ID detection is implemented on a microcontroller MSP430F5529 by calculating the correlation between the two segments of the PN sequence with the specified separation gap. When the gap length is matched, the correlator outputs a peak which triggers the wake-up enable. The time index of the correlator peak is used as the coarse synchronization of the data frame. The correlator is implemented by an iterative algorithm that uses only one multiplication and two additions for each sample input regardless of the length of the PN sequence, thus achieving low computational complexity. The real-time processing requirement is also met via direct memory access (DMA) and two circular buffers to accelerate data transfer between the peripherals and the memory. The proposed dual PN detection scheme has been successfully tested by simulated fading channels and real-world measured channels. The results show that, in long multipath channels with more than 60 taps, the proposed scheme achieves high detection rate and low false alarm rate using maximal-length sequences as short as 31 bits to 127 bits, therefore it is suitable as a low-power wake-up receiver. The future research will integrate the wake-up receiver with Digital Signal Processors (DSP) for payload detection.

  3. Sensor Network Architectures for Monitoring Underwater Pipelines

    PubMed Central

    Mohamed, Nader; Jawhar, Imad; Al-Jaroodi, Jameela; Zhang, Liren

    2011-01-01

    This paper develops and compares different sensor network architecture designs that can be used for monitoring underwater pipeline infrastructures. These architectures are underwater wired sensor networks, underwater acoustic wireless sensor networks, RF (Radio Frequency) wireless sensor networks, integrated wired/acoustic wireless sensor networks, and integrated wired/RF wireless sensor networks. The paper also discusses the reliability challenges and enhancement approaches for these network architectures. The reliability evaluation, characteristics, advantages, and disadvantages among these architectures are discussed and compared. Three reliability factors are used for the discussion and comparison: the network connectivity, the continuity of power supply for the network, and the physical network security. In addition, the paper also develops and evaluates a hierarchical sensor network framework for underwater pipeline monitoring. PMID:22346669

  4. Sensor network architectures for monitoring underwater pipelines.

    PubMed

    Mohamed, Nader; Jawhar, Imad; Al-Jaroodi, Jameela; Zhang, Liren

    2011-01-01

    This paper develops and compares different sensor network architecture designs that can be used for monitoring underwater pipeline infrastructures. These architectures are underwater wired sensor networks, underwater acoustic wireless sensor networks, RF (radio frequency) wireless sensor networks, integrated wired/acoustic wireless sensor networks, and integrated wired/RF wireless sensor networks. The paper also discusses the reliability challenges and enhancement approaches for these network architectures. The reliability evaluation, characteristics, advantages, and disadvantages among these architectures are discussed and compared. Three reliability factors are used for the discussion and comparison: the network connectivity, the continuity of power supply for the network, and the physical network security. In addition, the paper also develops and evaluates a hierarchical sensor network framework for underwater pipeline monitoring.

  5. A Geometric Modelling Approach to Determining the Best Sensing Coverage for 3-Dimensional Acoustic Target Tracking in Wireless Sensor Networks

    PubMed Central

    Pashazadeh, Saeid; Sharifi, Mohsen

    2009-01-01

    Existing 3-dimensional acoustic target tracking methods that use wired/wireless networked sensor nodes to track targets based on four sensing coverage do not always compute the feasible spatio-temporal information of target objects. To investigate this discrepancy in a formal setting, we propose a geometric model of the target tracking problem alongside its equivalent geometric dual model that is easier to solve. We then study and prove some properties of dual model by exploiting its relationship with algebra. Based on these properties, we propose a four coverage axis line method based on four sensing coverage and prove that four sensing coverage always yields two dual correct answers; usually one of them is infeasible. By showing that the feasible answer can be only sometimes identified by using a simple time test method such as the one proposed by ourselves, we prove that four sensing coverage fails to always yield the feasible spatio-temporal information of a target object. We further prove that five sensing coverage always gives the feasible position of a target object under certain conditions that are discussed in this paper. We propose three extensions to four coverage axis line method, namely, five coverage extent point method, five coverage extended axis lines method, and five coverage redundant axis lines method. Computation and time complexities of all four proposed methods are equal in the worst cases as well as on average being equal to Θ(1) each. Proposed methods and proved facts about capabilities of sensing coverage degree in this paper can be used in all other methods of acoustic target tracking like Bayesian filtering methods. PMID:22423198

  6. Surface acoustic wave (SAW) vibration sensors.

    PubMed

    Filipiak, Jerzy; Solarz, Lech; Steczko, Grzegorz

    2011-01-01

    In the paper a feasibility study on the use of surface acoustic wave (SAW) vibration sensors for electronic warning systems is presented. The system is assembled from concatenated SAW vibration sensors based on a SAW delay line manufactured on a surface of a piezoelectric plate. Vibrations of the plate are transformed into electric signals that allow identification of the sensor and localization of a threat. The theoretical study of sensor vibrations leads us to the simple isotropic model with one degree of freedom. This model allowed an explicit description of the sensor plate movement and identification of the vibrating sensor. Analysis of frequency response of the ST-cut quartz sensor plate and a damping speed of its impulse response has been conducted. The analysis above was the basis to determine the ranges of parameters for vibrating plates to be useful in electronic warning systems. Generally, operation of electronic warning systems with SAW vibration sensors is based on the analysis of signal phase changes at the working frequency of delay line after being transmitted via two circuits of concatenated four-terminal networks. Frequencies of phase changes are equal to resonance frequencies of vibrating plates of sensors. The amplitude of these phase changes is proportional to the amplitude of vibrations of a sensor plate. Both pieces of information may be sent and recorded jointly by a simple electrical unit.

  7. Surface acoustic wave (SAW) vibration sensors.

    PubMed

    Filipiak, Jerzy; Solarz, Lech; Steczko, Grzegorz

    2011-01-01

    In the paper a feasibility study on the use of surface acoustic wave (SAW) vibration sensors for electronic warning systems is presented. The system is assembled from concatenated SAW vibration sensors based on a SAW delay line manufactured on a surface of a piezoelectric plate. Vibrations of the plate are transformed into electric signals that allow identification of the sensor and localization of a threat. The theoretical study of sensor vibrations leads us to the simple isotropic model with one degree of freedom. This model allowed an explicit description of the sensor plate movement and identification of the vibrating sensor. Analysis of frequency response of the ST-cut quartz sensor plate and a damping speed of its impulse response has been conducted. The analysis above was the basis to determine the ranges of parameters for vibrating plates to be useful in electronic warning systems. Generally, operation of electronic warning systems with SAW vibration sensors is based on the analysis of signal phase changes at the working frequency of delay line after being transmitted via two circuits of concatenated four-terminal networks. Frequencies of phase changes are equal to resonance frequencies of vibrating plates of sensors. The amplitude of these phase changes is proportional to the amplitude of vibrations of a sensor plate. Both pieces of information may be sent and recorded jointly by a simple electrical unit. PMID:22247694

  8. Cascading multi-hop reservation and transmission in underwater acoustic sensor networks.

    PubMed

    Lee, Jae-Won; Cho, Ho-Shin

    2014-01-01

    The long propagation delay in an underwater acoustic channel makes designing an underwater media access control (MAC) protocol more challenging. In particular, handshaking-based MAC protocols widely used in terrestrial radio channels have been known to be inappropriate in underwater acoustic channels, because of the inordinately large latency involved in exchanging control packets. Furthermore, in the case of multi-hop relaying in a hop-by-hop handshaking manner, the end-to-end delay significantly increases. In this paper, we propose a new MAC protocol named cascading multi-hop reservation and transmission (CMRT). In CMRT, intermediate nodes between a source and a destination may start handshaking in advance for the next-hop relaying before handshaking for the previous node is completed. By this concurrent relaying, control packet exchange and data delivery cascade down to the destination. In addition, to improve channel utilization, CMRT adopts a packet-train method where multiple data packets are sent together by handshaking once. Thus, CMRT reduces the time taken for control packet exchange and accordingly increases the throughput. The performance of CMRT is evaluated and compared with that of two conventional MAC protocols (multiple-access collision avoidance for underwater (MACA-U) and MACA-U with packet trains (MACA-UPT)). The results show that CMRT outperforms other MAC protocols in terms of both throughput and end-to-end delay.

  9. Cascading multi-hop reservation and transmission in underwater acoustic sensor networks.

    PubMed

    Lee, Jae-Won; Cho, Ho-Shin

    2014-01-01

    The long propagation delay in an underwater acoustic channel makes designing an underwater media access control (MAC) protocol more challenging. In particular, handshaking-based MAC protocols widely used in terrestrial radio channels have been known to be inappropriate in underwater acoustic channels, because of the inordinately large latency involved in exchanging control packets. Furthermore, in the case of multi-hop relaying in a hop-by-hop handshaking manner, the end-to-end delay significantly increases. In this paper, we propose a new MAC protocol named cascading multi-hop reservation and transmission (CMRT). In CMRT, intermediate nodes between a source and a destination may start handshaking in advance for the next-hop relaying before handshaking for the previous node is completed. By this concurrent relaying, control packet exchange and data delivery cascade down to the destination. In addition, to improve channel utilization, CMRT adopts a packet-train method where multiple data packets are sent together by handshaking once. Thus, CMRT reduces the time taken for control packet exchange and accordingly increases the throughput. The performance of CMRT is evaluated and compared with that of two conventional MAC protocols (multiple-access collision avoidance for underwater (MACA-U) and MACA-U with packet trains (MACA-UPT)). The results show that CMRT outperforms other MAC protocols in terms of both throughput and end-to-end delay. PMID:25275349

  10. Improvement of optical and acoustical technologies for the protection: Project IMOTEP: Network of heterogeneous sensor types for the protection of camps or mobile troops

    NASA Astrophysics Data System (ADS)

    Hengy, Sébastien; Laurenzis, Martin; Zimpfer, Véronique; Schneider, Armin

    2014-10-01

    Snipers have emerged as a major threat to troops in recent conflicts. To reduce this menace, the objective of the French- German Research Institute of Saint Louis (ISL) research project "IMOTEP" is to improve the detection of snipers on the battlefield. Our basic approach is to combine several sources of information for a fast and appropriate reaction when an unusual signal (e.g. a flash or a shot) is detected. The project includes several technologies developed at ISL: acoustical detection, fusion of distributed sensor network data, active imaging and 3D audio communication. The protection of camps, convoys or dismounted soldiers rests on a distributed acoustical sensor network that detects and localizes sniper attacks. An early estimation of the threat position is transmitted through a network to an active imaging system in order to confirm and refine this position by 3D imaging. The refined position is then sent to the control center which generates an alert message that displays the threat position using two formats: a tactical map and a 3D audio signal. In addition, the camp is protected by an ad-hoc sensor network used for intruder detection.

  11. An improved DS acoustic-seismic modality fusion algorithm based on a new cascaded fuzzy classifier for ground-moving targets classification in wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Pan, Qiang; Wei, Jianming; Cao, Hongbing; Li, Na; Liu, Haitao

    2007-04-01

    A new cascaded fuzzy classifier (CFC) is proposed to implement ground-moving targets classification tasks locally at sensor nodes in wireless sensor networks (WSN). The CFC is composed of three and two binary fuzzy classifiers (BFC) respectively in seismic and acoustic signal channel in order to classify person, Light-wheeled (LW) Vehicle, and Heavywheeled (HW) Vehicle in presence of environmental background noise. Base on the CFC, a new basic belief assignment (bba) function is defined for each component BFC to give out a piece of evidence instead of a hard decision label. An evidence generator is used to synthesize available evidences from BFCs into channel evidences and channel evidences are further temporal-fused. Finally, acoustic-seismic modality fusion using Dempster-Shafer method is performed. Our implementation gives significantly better performance than the implementation with majority-voting fusion method through leave-one-out experiments.

  12. Frustrated total internal reflection acoustic field sensor

    DOEpatents

    Kallman, Jeffrey S.

    2000-01-01

    A frustrated total internal reflection acoustic field sensor which allows the acquisition of the acoustic field over an entire plane, all at once. The sensor finds use in acoustic holography and acoustic diffraction tomography. For example, the sensor may be produced by a transparent plate with transparent support members tall enough to support one or more flexible membranes at an appropriate height for frustrated total internal reflection to occur. An acoustic wave causes the membrane to deflect away from its quiescent position and thus changes the amount of light that tunnels through the gap formed by the support members and into the membrane, and so changes the amount of light reflected by the membrane. The sensor(s) is illuminated by a uniform tight field, and the reflection from the sensor yields acoustic wave amplitude and phase information which can be picked up electronically or otherwise.

  13. Acoustic optic hybrid (AOH) sensor

    PubMed

    Matthews; Arrieta

    2000-09-01

    The ability of laser vibrometers to receive and process acoustic echoes from the water surface above a submerged target is established and evaluated. Sonar echoes from a submerged target are collected from the water surface by a laser vibrometer. Feasibility of this approach to sensing underwater sound is demonstrated. If the acoustic excitation at an otherwise undisturbed water surface is 195 to 168 dB re: 1 microPa, signal-to-noise ratio (SNR), at the vibrometer output, is shown to range from about 46 to 6 dB. Capillary waves and gravity waves at the water surface are expected and shown to have some destructive effect on the process of echo retrieval. A series of experiments to quantify the surface wave effects is described. The wave experiment results are reported. A successful attempt to acquire echoes from a submerged target over a grid of points for further processing into a three-dimensional image is made and described. The data acquisition and beamforming techniques constitute a three-dimensional, acoustic optic, synthetic aperture sonar (SAS). Beamformed images are included. For an aircraft towing acoustic sensors through the water with a mechanical link, this technique holds the promise of increased safety and improved fuel efficiency. PMID:11008811

  14. Acoustic optic hybrid (AOH) sensor

    PubMed

    Matthews; Arrieta

    2000-09-01

    The ability of laser vibrometers to receive and process acoustic echoes from the water surface above a submerged target is established and evaluated. Sonar echoes from a submerged target are collected from the water surface by a laser vibrometer. Feasibility of this approach to sensing underwater sound is demonstrated. If the acoustic excitation at an otherwise undisturbed water surface is 195 to 168 dB re: 1 microPa, signal-to-noise ratio (SNR), at the vibrometer output, is shown to range from about 46 to 6 dB. Capillary waves and gravity waves at the water surface are expected and shown to have some destructive effect on the process of echo retrieval. A series of experiments to quantify the surface wave effects is described. The wave experiment results are reported. A successful attempt to acquire echoes from a submerged target over a grid of points for further processing into a three-dimensional image is made and described. The data acquisition and beamforming techniques constitute a three-dimensional, acoustic optic, synthetic aperture sonar (SAS). Beamformed images are included. For an aircraft towing acoustic sensors through the water with a mechanical link, this technique holds the promise of increased safety and improved fuel efficiency.

  15. Acoustic Source Localization via Time Difference of Arrival Estimation for Distributed Sensor Networks using Tera-scale Optical-Core Devices

    SciTech Connect

    Imam, Neena; Barhen, Jacob

    2009-01-01

    For real-time acoustic source localization applications, one of the primary challenges is the considerable growth in computational complexity associated with the emergence of ever larger, active or passive, distributed sensor networks. These sensors rely heavily on battery-operated system components to achieve highly functional automation in signal and information processing. In order to keep communication requirements minimal, it is desirable to perform as much processing on the receiver platforms as possible. However, the complexity of the calculations needed to achieve accurate source localization increases dramatically with the size of sensor arrays, resulting in substantial growth of computational requirements that cannot be readily met with standard hardware. One option to meet this challenge builds upon the emergence of digital optical-core devices. The objective of this work was to explore the implementation of key building block algorithms used in underwater source localization on the optical-core digital processing platform recently introduced by Lenslet Inc. This demonstration of considerably faster signal processing capability should be of substantial significance to the design and innovation of future generations of distributed sensor networks.

  16. Acoustic pressure-vector sensor array

    NASA Astrophysics Data System (ADS)

    Huang, Dehua; Elswick, Roy C.; McEachern, James F.

    2001-05-01

    Pressure-vector sensors measure both scalar and vector components of the acoustic field. December 2003 measurements at the NUWC Seneca Lake test facility verify previous observations that acoustic ambient noise spectrum levels measured by acoustic intensity sensors are reduced relative to either acoustic pressure or acoustic vector sensor spectrum levels. The Seneca measurements indicate a reduction by as much as 15 dB at the upper measurement frequency of 2500 Hz. A nonlinear array synthesis theory for pressure-vector sensors will be introduced that allows smaller apertures to achieve narrow beams. The significantly reduced ambient noise of individual pressure-vector elements observed in the ocean by others, and now at Seneca Lake, should allow a nonlinearly combined array to detect significantly lower levels than has been observed in previous multiplicative processing of pressure sensors alone. Nonlinear array synthesis of pressure-vector sensors differs from conventional super-directive algorithms that linearly combine pressure elements with positive and negative weights, thereby reducing the sensitivity of conventional super-directive arrays. The much smaller aperture of acoustic pressure-vector sensor arrays will be attractive for acoustic systems on underwater vehicles, as well as for other applications that require narrow beam acoustic receivers. [The authors gratefully acknowledge the support of ONR and NUWC.

  17. Improved Calibration Of Acoustic Plethysmographic Sensors

    NASA Technical Reports Server (NTRS)

    Zuckerwar, Allan J.; Davis, David C.

    1993-01-01

    Improved method of calibration of acoustic plethysmographic sensors involves acoustic-impedance test conditions like those encountered in use. Clamped aluminum tube holds source of sound (hydrophone) inside balloon. Test and reference sensors attached to outside of balloon. Sensors used to measure blood flow, blood pressure, heart rate, breathing sounds, and other vital signs from surfaces of human bodies. Attached to torsos or limbs by straps or adhesives.

  18. Acoustic sensor array extracts physiology during movement

    NASA Astrophysics Data System (ADS)

    Scanlon, Michael V.

    2001-08-01

    An acoustic sensor attached to a person's neck can extract heart and breath sounds, as well as voice and other physiology related to their health and performance. Soldiers, firefighters, law enforcement, and rescue personnel, as well as people at home or in health care facilities, can benefit form being remotely monitored. ARLs acoustic sensor, when worn around a person's neck, picks up the carotid artery and breath sounds very well by matching the sensor's acoustic impedance to that of the body via a gel pad, while airborne noise is minimized by an impedance mismatch. Although the physiological sounds have high SNR, the acoustic sensor also responds to motion-induced artifacts that obscure the meaningful physiology. To exacerbate signal extraction, these interfering signals are usually covariant with the heart sounds, in that as a person walks faster the heart tends to beat faster, and motion noises tend to contain low frequency component similar to the heart sounds. A noise-canceling configuration developed by ARL uses two acoustic sensor on the front sides of the neck as physiology sensors, and two additional acoustic sensor on the back sides of the neck as noise references. Breath and heart sounds, which occur with near symmetry and simultaneously at the two front sensor, will correlate well. The motion noise present on all four sensor will be used to cancel the noise on the two physiology sensors. This report will compare heart rate variability derived from both the acoustic array and from ECG data taken simultaneously on a treadmill test. Acoustically derived breath rate and volume approximations will be introduced as well. A miniature 3- axis accelerometer on the same neckband provides additional noise references to validate footfall and motion activity.

  19. Energy efficient sensor network implementations

    SciTech Connect

    Frigo, Janette R; Raby, Eric Y; Brennan, Sean M; Kulathumani, Vinod; Rosten, Ed; Wolinski, Christophe; Wagner, Charles; Charot, Francois

    2009-01-01

    In this paper, we discuss a low power embedded sensor node architecture we are developing for distributed sensor network systems deployed in a natural environment. In particular, we examine the sensor node for energy efficient processing-at-the-sensor. We analyze the following modes of operation; event detection, sleep(wake-up), data acquisition, data processing modes using low power, high performance embedded technology such as specialized embedded DSP processors and a low power FPGAs at the sensing node. We use compute intensive sensor node applications: an acoustic vehicle classifier (frequency domain analysis) and a video license plate identification application (learning algorithm) as a case study. We report performance and total energy usage for our system implementations and discuss the system architecture design trade offs.

  20. Lead-free acoustic emission sensors

    SciTech Connect

    Lam, K. H.; Lin, D. M.; Chan, H. L. W.

    2007-11-15

    Acoustic emission (AE) sensors have been fabricated using both soft- and hard-type lead-free (Na{sub 0.5}K{sub 0.5})NbO{sub 3}-based ceramics. The acoustic and electromechanical properties of the ceramics have been determined using the resonance technique. The lead-free AE sensors were calibrated using a laser source and compared to a commercial sensor. A lead zirconate titanate (PZT) 5H ceramics AE sensor has also been fabricated and calibrated for comparison. It was found that the sensitivity of lead-free AE sensors is comparable to that of the lead-based PZT sensor. To evaluate the sensors for potential application, they have been used in the detection of AE in an impact test. The lead-free sensors can reproduce AE signals accurately without giving artifacts and have potential use in commercial AE systems.

  1. Lead-free acoustic emission sensors.

    PubMed

    Lam, K H; Lin, D M; Chan, H L W

    2007-11-01

    Acoustic emission (AE) sensors have been fabricated using both soft- and hard-type lead-free (Na0.5K0.5)NbO3-based ceramics. The acoustic and electromechanical properties of the ceramics have been determined using the resonance technique. The lead-free AE sensors were calibrated using a laser source and compared to a commercial sensor. A lead zirconate titanate (PZT) 5H ceramics AE sensor has also been fabricated and calibrated for comparison. It was found that the sensitivity of lead-free AE sensors is comparable to that of the lead-based PZT sensor. To evaluate the sensors for potential application, they have been used in the detection of AE in an impact test. The lead-free sensors can reproduce AE signals accurately without giving artifacts and have potential use in commercial AE systems.

  2. Ocean current mapping using networked distributed sensors

    NASA Astrophysics Data System (ADS)

    Huang, Chen-Fen; Yang, T. C.; Liu, Jin-Yuan; Burchfield, Tom; Schindall, Jeff

    2012-11-01

    Distributed underwater sensors are expected to provide environmental (oceanographic) monitoring over large areas. As fabrication technology advances, low cost sensors will be available for many applications. The sensors communicate to each other and are networked using acoustic communications. This paper proposes a method for ocean current tomography using distributed networked sensors and presents preliminary experimental results by this approach. Conventional acoustic tomography uses the acoustic sensors distributed on the periphery of an area of interest. Environmental reconstruction requires solving a challenging high dimensional inverse problem, typically requiring substantial computational effort. Given distributed sensors, currents can be constructed locally based on data from neighboring sensors. It is shown using simulated data that results obtained by the proposed method are similar to those obtained by a conventional tomographic method based on peripheral sensors. In addition, one finds that the distributed sensors consume much less energy than that by the conventional tomographic approach. An acoustic communication and networking experiment was conducted near the Sizihwan Bay in Kaohsiung, Taiwan, in May 2011. The communication signals are analyzed to measure currents as a function of space and time. The procedure is simple and can be implemented in real-time using in-buoy processing.

  3. Advanced fiber-optic acoustic sensors

    NASA Astrophysics Data System (ADS)

    Teixeira, João G. V.; Leite, Ivo T.; Silva, Susana; Frazão, Orlando

    2014-09-01

    Acoustic sensing is nowadays a very demanding field which plays an important role in modern society, with applications spanning from structural health monitoring to medical imaging. Fiber-optics can bring many advantages to this field, and fiber-optic acoustic sensors show already performance levels capable of competing with the standard sensors based on piezoelectric transducers. This review presents the recent advances in the field of fiber-optic dynamic strain sensing, particularly for acoustic detection. Three dominant technologies are identified — fiber Bragg gratings, interferometric Mach-Zehnder, and Fabry-Pérot configurations — and their recent developments are summarized.

  4. Characterization Test Report for the Mnemonics-UCS Wireless Surface Acoustic Wave Sensor System

    NASA Technical Reports Server (NTRS)

    Duncan, Joshua J.; Youngquist, Robert C.

    2013-01-01

    The scope of this testing includes the Surface Acoustic Wave Sensor System delivered to KSC: two interrogator (transceiver) systems, four temperature sensors, with wooden mounting blocks, two antennas, two power supplies, network cables, and analysis software. Also included are a number of additional temperature sensors and newly-developed hydrogen sensors

  5. Wireless Multiplexed Surface Acoustic Wave Sensors Project

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C.

    2014-01-01

    Wireless Surface Acoustic Wave (SAW) Sensor is a new technology for obtaining multiple, real-time measurements under extreme environmental conditions. This project plans to develop a wireless multiplexed sensor system that uses SAW sensors, with no batteries or semiconductors, that are passive and rugged, can operate down to cryogenic temperatures and up to hundreds of degrees C, and can be used to sense a wide variety of parameters over reasonable distances (meters).

  6. Acoustic sensors using microstructures tunable with energy other than acoustic energy

    DOEpatents

    Datskos, Panagiotis G.

    2003-11-25

    A sensor for detecting acoustic energy includes a microstructure tuned to a predetermined acoustic frequency and a device for detecting movement of the microstructure. A display device is operatively linked to the movement detecting device. When acoustic energy strikes the acoustic sensor, acoustic energy having a predetermined frequency moves the microstructure, where the movement is detected by the movement detecting device.

  7. Acoustic sensors using microstructures tunable with energy other than acoustic energy

    DOEpatents

    Datskos, Panagiotis G.

    2005-06-07

    A sensor for detecting acoustic energy includes a microstructure tuned to a predetermined acoustic frequency and a device for detecting movement of the microstructure. A display device is operatively linked to the movement detecting device. When acoustic energy strikes the acoustic sensor, acoustic energy having a predetermined frequency moves the microstructure, where the movement is detected by the movement detecting device.

  8. Wireless Sensors Network (Sensornet)

    NASA Technical Reports Server (NTRS)

    Perotti, J.

    2003-01-01

    The Wireless Sensor Network System presented in this paper provides a flexible reconfigurable architecture that could be used in a broad range of applications. It also provides a sensor network with increased reliability; decreased maintainability costs, and assured data availability by autonomously and automatically reconfiguring to overcome communication interferences.

  9. One sensor acoustic emission localization in plates.

    PubMed

    Ernst, R; Zwimpfer, F; Dual, J

    2016-01-01

    Acoustic emissions are elastic waves accompanying damage processes and are therefore used for monitoring the health state of structures. Most of the traditional acoustic emission techniques use a trilateration approach requiring at least three sensors on a 2D domain in order to localize sources of acoustic emission events. In this paper, we present a new approach which requires only a single sensor to identify and localize the source of acoustic emissions in a finite plate. The method proposed makes use of the time reversal principle and the dispersive nature of the flexural wave mode in a suitable frequency band. The signal shape of the transverse velocity response contains information about the propagated paths of the incoming elastic waves. This information is made accessible by a numerical time reversal simulation. The effect of dispersion is reversed and the original shape of the flexural wave is restored at the origin of the acoustic emission. The time reversal process is analyzed first for an infinite Mindlin plate, then by a 3D FEM simulation which in combination results in a novel acoustic emission localization process. The process is experimentally verified for different aluminum plates for artificially generated acoustic emissions (Hsu-Nielsen source). Good and reliable localization was achieved for a homogeneous quadratic aluminum plate with only one measurement. PMID:26372509

  10. Multipurpose Acoustic Sensor for Downhole Fluid Monitoring

    SciTech Connect

    Pantea, Cristian

    2012-05-04

    The projects objectives and purpose are to: (1) development a multipurpose acoustic sensor for downhole fluid monitoring in Enhanced Geothermal Systems (EGS) reservoirs over typical ranges of pressures and temperatures and demonstrate its capabilities and performance for different EGS systems; (2) determine in real-time and in a single sensor package several parameters - temperature, pressure, fluid flow and fluid properties; (3) needed in nearly every phase of an EGS project, including Testing of Injection and Production Wells, Reservoir Validation, Inter-well Connectivity, Reservoir Scale Up and Reservoir Sustainability. (4) Current sensors are limited to operating at lower temperatures, but the need is for logging at high temperatures. The present project deals with the development of a novel acoustic-based sensor that can work at temperatures up to 374 C, in inhospitable environments.

  11. Sensor Authentication in Collaborating Sensor Networks

    SciTech Connect

    Bielefeldt, Jake Uriah

    2014-11-01

    In this thesis, we address a new security problem in the realm of collaborating sensor networks. By collaborating sensor networks, we refer to the networks of sensor networks collaborating on a mission, with each sensor network is independently owned and operated by separate entities. Such networks are practical where a number of independent entities can deploy their own sensor networks in multi-national, commercial, and environmental scenarios, and some of these networks will integrate complementary functionalities for a mission. In the scenario, we address an authentication problem wherein the goal is for the Operator Oi of Sensor Network Si to correctly determine the number of active sensors in Network Si. Such a problem is challenging in collaborating sensor networks where other sensor networks, despite showing an intent to collaborate, may not be completely trustworthy and could compromise the authentication process. We propose two authentication protocols to address this problem. Our protocols rely on Physically Unclonable Functions, which are a hardware based authentication primitive exploiting inherent randomness in circuit fabrication. Our protocols are light-weight, energy efficient, and highly secure against a number of attacks. To the best of our knowledge, ours is the first to addresses a practical security problem in collaborating sensor networks.

  12. Surface acoustic wave oxygen sensor

    NASA Technical Reports Server (NTRS)

    Collman, James P.; Oglesby, Donald M.; Upchurch, Billy T.; Leighty, Bradley D.; Zhang, Xumu; Herrmann, Paul C.

    1994-01-01

    A surface acoustic wave (SAW) device that responds to oxygen pressure was developed by coating a 158 MHz quartz surface acoustic wave (SAW) device with an oxygen binding agent. Two types of coatings were used. One type was prepared by dissolving an oxygen binding agent in a toluene solution of a copolymer containing the axial ligand. A second type was prepared with an oxygen binding porphyrin solution containing excess axial ligand without a polymer matrix. In the polymer based coatings, the copolymer served to provide the axial ligand to the oxygen binding agent and as a coating matrix on the surface of the SAW device. The oxygen sensing SAW device has been shown to bind oxygen following a Langmuir isotherm and may be used to measure the equilibrium constant of the oxygen binding compound in the coating matrix.

  13. Development of an accelerometer-based underwater acoustic intensity sensor.

    PubMed

    Kim, Kang; Gabrielson, Thomas B; Lauchle, Gerald C

    2004-12-01

    An underwater acoustic intensity sensor is described. This sensor derives acoustic intensity from simultaneous, co-located measurement of the acoustic pressure and one component of the acoustic particle acceleration vector. The sensor consists of a pressure transducer in the form of a hollow piezoceramic cylinder and a pair of miniature accelerometers mounted inside the cylinder. Since this sensor derives acoustic intensity from measurement of acoustic pressure and acoustic particle acceleration, it is called a p-a intensity probe. The sensor is ballasted to be nearly neutrally buoyant. It is desirable for the accelerometers to measure only the rigid body motion of the assembled probe and for the effective centers of the pressure sensor and accelerometer to be coincident. This is achieved by symmetric disposition of a pair of accelerometers inside the ceramic cylinder. The response of the intensity probe is determined by comparison with a reference hydrophone in a predominantly reactive acoustic field.

  14. Sustainable coastal sensor networks: technologies and challenges

    NASA Astrophysics Data System (ADS)

    Carapezza, Edward M.; Butman, Jerry; Babb, Ivar; Bucklin, Ann

    2008-04-01

    This paper describes a distributed sensor network for a coastal maritime security system. This concept incorporates a network of small passive and active multi-phenomenological unattended sensors and shore based optical sensors to detect, classify, and track submerged threat objects approaching high value coastal assets, such as ports, harbors, residential, commercial, and military facilities and areas. The network of unattended, in-water sensors perform the initial detection, classification, and coarse tracking and then queues shore based optical laser radar sensors. These shore-based sensors perform a queued sector search to develop a refined track on the submerged threat objects that were initially detected by the unattended sensor network. Potential threat objects include swimmers, small unmanned underwater vehicles (UUV's), small submarines, and submerged barges. All of these threats have the potential to transport threat objects such as explosives, chemical, biological, radiological, and nuclear materials. Reliable systems with low false alarm rates (FAR) are proposed. Tens to hundreds of low cost passive sensors are proposed to be deployed conjunctively with several active acoustic and optical sensors in threat and facility dependant patterns to maximize the detection, tracking and classification of submerged threat objects. The integrated command and control system and novel microbial fuel cells to power these sensor networks are also described.

  15. Fiber based photonic-crystal acoustic sensor

    NASA Astrophysics Data System (ADS)

    Kilic, Onur

    Photonic-crystal slabs are two-dimensional photonic crystals etched into a dielectric layer such as silicon. Standard micro fabrication techniques can be employed to manufacture these structures, which makes it feasible to produce them in large areas, usually an important criterion for practical applications. An appealing feature of these structures is that they can be employed as free-space optical devices such as broadband reflectors. The small thickness of the slab (usually in the vicinity of half a micron) also makes it deflectable. These combined optical and mechanical properties make it possible to employ photonic-crystal slabs in a range of practical applications, including displacement sensors, which in turn can be used for example to detect acoustic waves. An additional benefit of employing a photonic-crystal slab is that it is possible to tailor its optical and mechanical properties by adjusting the geometrical parameters of the structure such as hole radius or shape, pitch, and the slab thickness. By altering the hole radius and pitch, it is possible to make broadband reflectors or sharp transmission filters out of these structures. Adjusting the thickness also affects its deformability, making it possible to make broadband mirrors compliant to acoustic waves. Altering the hole shape, for example by introducing an asymmetry, extends the functionalities of photonic-crystal slabs even further. Breaking the symmetry by introducing asymmetric holes enables polarization-sensitive devices such as retarders, polarization beam splitters, and photonic crystals with additional non-degenerate resonances useful for increased sensitivity in sensors. All these practical advantages of photonic-crystal slabs makes them suitable as key components in micromachined sensor applications. We report one such example of an application of photonic-crystal slabs in the form of a micromachined acoustic sensor. It consists of a Fabry-Perot interferometer made of a photonic

  16. Acoustic modes in fluid networks

    NASA Technical Reports Server (NTRS)

    Michalopoulos, C. D.; Clark, Robert W., Jr.; Doiron, Harold H.

    1992-01-01

    Pressure and flow rate eigenvalue problems for one-dimensional flow of a fluid in a network of pipes are derived from the familiar transmission line equations. These equations are linearized by assuming small velocity and pressure oscillations about mean flow conditions. It is shown that the flow rate eigenvalues are the same as the pressure eigenvalues and the relationship between line pressure modes and flow rate modes is established. A volume at the end of each branch is employed which allows any combination of boundary conditions, from open to closed, to be used. The Jacobi iterative method is used to compute undamped natural frequencies and associated pressure/flow modes. Several numerical examples are presented which include acoustic modes for the Helium Supply System of the Space Shuttle Orbiter Main Propulsion System. It should be noted that the method presented herein can be applied to any one-dimensional acoustic system involving an arbitrary number of branches.

  17. Robust Forecasting for Energy Efficiency of Wireless Multimedia Sensor Networks

    PubMed Central

    Wang, Xue; Ma, Jun-Jie; Ding, Liang; Bi, Dao-Wei

    2007-01-01

    An important criterion of wireless sensor network is the energy efficiency in specified applications. In this wireless multimedia sensor network, the observations are derived from acoustic sensors. Focused on the energy problem of target tracking, this paper proposes a robust forecasting method to enhance the energy efficiency of wireless multimedia sensor networks. Target motion information is acquired by acoustic sensor nodes while a distributed network with honeycomb configuration is constructed. Thereby, target localization is performed by multiple sensor nodes collaboratively through acoustic signal processing. A novel method, combining autoregressive moving average (ARMA) model and radial basis function networks (RBFNs), is exploited to perform robust target position forecasting during target tracking. Then sensor nodes around the target are awakened according to the forecasted target position. With committee decision of sensor nodes, target localization is performed in a distributed manner and the uncertainty of detection is reduced. Moreover, a sensor-to-observer routing approach of the honeycomb mesh network is investigated to solve the data reporting considering the residual energy of sensor nodes. Target localization and forecasting are implemented in experiments. Meanwhile, sensor node awakening and dynamic routing are evaluated. Experimental results verify that energy efficiency of wireless multimedia sensor network is enhanced by the proposed target tracking method.

  18. Protein adsorption to organosiloxane surfaces studied by acoustic wave sensor.

    PubMed

    Cavic, B A; Thompson, M

    1998-10-01

    Surfaces of the two organosiloxanes, polymercaptopropylmethylsiloxane and octaphenylcyclotetrasiloxane, were prepared on the gold electrodes of thickness-shear mode acoustic wave sensors. Compounds containing the siloxane bond are important in the fabrication of medical implants. The flow-through adsorption of the proteins: human serum albumin, alpha-chymotripsinogen A, cytochrome c, fibrinogen, hemoglobin, immunoglobulin G and apo-transferrin to the two siloxane surfaces and a gold electrode were detected by acoustic network analysis. With the exception of minor wash-off by buffer flow, the adsorption of all proteins to the three surfaces is irreversible. Differences observed for the magnitudes of adsorption for the various cases are ascribed to the role played by molecular interactions at the liquid/solid interface. The results confirm that changes in series resonant frequencies caused by macromolecular adsorption differ significantly from the widely accepted "mass based" model usually employed to characterize the response of this type of acoustic wave device.

  19. Modular sensor network node

    DOEpatents

    Davis, Jesse Harper Zehring; Stark, Jr., Douglas Paul; Kershaw, Christopher Patrick; Kyker, Ronald Dean

    2008-06-10

    A distributed wireless sensor network node is disclosed. The wireless sensor network node includes a plurality of sensor modules coupled to a system bus and configured to sense a parameter. The parameter may be an object, an event or any other parameter. The node collects data representative of the parameter. The node also includes a communication module coupled to the system bus and configured to allow the node to communicate with other nodes. The node also includes a processing module coupled to the system bus and adapted to receive the data from the sensor module and operable to analyze the data. The node also includes a power module connected to the system bus and operable to generate a regulated voltage.

  20. Underwater sensor networks: applications, advances and challenges.

    PubMed

    Heidemann, John; Stojanovic, Milica; Zorzi, Michele

    2012-01-13

    This paper examines the main approaches and challenges in the design and implementation of underwater wireless sensor networks. We summarize key applications and the main phenomena related to acoustic propagation, and discuss how they affect the design and operation of communication systems and networking protocols at various layers. We also provide an overview of communications hardware, testbeds and simulation tools available to the research community.

  1. Acoustic emission location on aluminum alloy structure by using FBG sensors and PSO method

    NASA Astrophysics Data System (ADS)

    Lu, Shizeng; Jiang, Mingshun; Sui, Qingmei; Dong, Huijun; Sai, Yaozhang; Jia, Lei

    2016-04-01

    Acoustic emission location is important for finding the structural crack and ensuring the structural safety. In this paper, an acoustic emission location method by using fiber Bragg grating (FBG) sensors and particle swarm optimization (PSO) algorithm were investigated. Four FBG sensors were used to form a sensing network to detect the acoustic emission signals. According to the signals, the quadrilateral array location equations were established. By analyzing the acoustic emission signal propagation characteristics, the solution of location equations was converted to an optimization problem. Thus, acoustic emission location can be achieved by using an improved PSO algorithm, which was realized by using the information fusion of multiple standards PSO, to solve the optimization problem. Finally, acoustic emission location system was established and verified on an aluminum alloy plate. The experimental results showed that the average location error was 0.010 m. This paper provided a reliable method for aluminum alloy structural acoustic emission location.

  2. Programming Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Lopes, Luís; Martins, Francisco; Barros, João

    Sensor networks can be viewed as a collection of tiny, low-cost devices programmed to sense the physical world and that communicate over radio links [12]. The devices are commonly called motes or smart dust [676], in allusion to their computational and sensing capabilities, as well as their increasingly small size.

  3. Acoustic and Seismic Modalities for Unattended Ground Sensors

    SciTech Connect

    Elbring, G.J.; Ladd, M.D.; McDonald, T.S.; Sleefe, G.E.

    1999-03-31

    In this paper, we have presented the relative advantages and complementary aspects of acoustic and seismic ground sensors. A detailed description of both acoustic and seismic ground sensing methods has been provided. Acoustic and seismic phenomenology including source mechanisms, propagation paths, attenuation, and sensing have been discussed in detail. The effects of seismo-acoustic and acousto-seismic interactions as well as recommendations for minimizing seismic/acoustic cross talk have been highlighted. We have shown representative acoustic and seismic ground sensor data to illustrate the advantages and complementary aspects of the two modalities. The data illustrate that seismic transducers often respond to acoustic excitation through acousto-seismic coupling. Based on these results, we discussed the implications of this phenomenology on the detection, identification, and localization objectives of unattended ground sensors. We have concluded with a methodology for selecting the preferred modality (acoustic and/or seismic) for a particular application.

  4. Surface acoustic wave devices for sensor applications

    NASA Astrophysics Data System (ADS)

    Bo, Liu; Xiao, Chen; Hualin, Cai; Mohammad, Mohammad Ali; Xiangguang, Tian; Luqi, Tao; Yi, Yang; Tianling, Ren

    2016-02-01

    Surface acoustic wave (SAW) devices have been widely used in different fields and will continue to be of great importance in the foreseeable future. These devices are compact, cost efficient, easy to fabricate, and have a high performance, among other advantages. SAW devices can work as filters, signal processing units, sensors and actuators. They can even work without batteries and operate under harsh environments. In this review, the operating principles of SAW sensors, including temperature sensors, pressure sensors, humidity sensors and biosensors, will be discussed. Several examples and related issues will be presented. Technological trends and future developments will also be discussed. Project supported by the National Natural Science Foundation of China (Nos. 60936002, 61025021, 61434001, 61574083), the State Key Development Program for Basic Research of China (No. 2015CB352100), the National Key Project of Science and Technology (No. 2011ZX02403-002) and the Special Fund for Agroscientific Research in the Public Interest of China (No. 201303107). M.A.M is additionally supported by the Postdoctoral Fellowship (PDF) program of the Natural Sciences and Engineering Research Council (NSERC) of Canada and the China Postdoctoral Science Foundation (CPSF).

  5. Cooperative implementation of a high temperature acoustic sensor

    NASA Astrophysics Data System (ADS)

    Baldini, S. E.; Nowakowski, Edward; Smith, Herbert G.; Friebele, E. J.; Putnam, Martin A.; Rogowski, Robert; Melvin, Leland D.; Claus, Richard O.; Tran, Tuan; Holben, Milford S., Jr.

    1991-12-01

    The current status and results of a cooperative program aimed at the implementation of a high-temperature acoustic/strain sensor onto metallic structures are reported. The sensor systems that are to be implemented under this program will measure thermal expansion, maneuver loads, aircraft buffet, sonic fatigue, and acoustic emissions in environments that approach 1800 F. The discussion covers fiber development, fabrication of an extrinsic Fabry-Perot interferometer acoustic sensor, sensor mounting/integration, and results of an evaluation of the sensor capabilities.

  6. Cooperative implementation of a high temperature acoustic sensor

    NASA Technical Reports Server (NTRS)

    Baldini, S. E.; Nowakowski, Edward; Smith, Herbert G.; Friebele, E. J.; Putnam, Martin A.; Rogowski, Robert; Melvin, Leland D.; Claus, Richard O.; Tran, Tuan; Holben, Milford S., Jr.

    1991-01-01

    The current status and results of a cooperative program aimed at the implementation of a high-temperature acoustic/strain sensor onto metallic structures are reported. The sensor systems that are to be implemented under this program will measure thermal expansion, maneuver loads, aircraft buffet, sonic fatigue, and acoustic emissions in environments that approach 1800 F. The discussion covers fiber development, fabrication of an extrinsic Fabry-Perot interferometer acoustic sensor, sensor mounting/integration, and results of an evaluation of the sensor capabilities.

  7. Attack detection in unattended sensor networks

    NASA Astrophysics Data System (ADS)

    Wu, Curt; Monnier, Camille; Fry, Gerald; Girod, Lewis; Luke, Jahn

    2010-04-01

    Because sensor networks are often deployed in hostile environments where their security and integrity may be compromised, it is essential to maximize the reliability and trustworthiness of existing and envisioned sensor networks. During operations, the sensor network must be robust to deception, node compromise, and various other attacks, while maintaining the operator's situational awareness regarding the health and integrity of the system. To address these needs, we have designed a Framework to Ensure and Assess Trustworthiness in Sensor systems (FEATS) to identify attacks on sensor system integrity and inform the operator of sensor data trustworthiness. We have developed and validated unsupervised anomaly detection algorithms for sensor data captured from an experimental acoustic sensor platform under a number of attack scenarios. The platform, which contains four audio microphones, was exposed to two physical attacks (audio filtering and audio playback) as well as a live replay attack (replaying live audio data that is captured at a remote location), which is analogous to a wormhole attack in the routing layer. With our unsupervised learning algorithms, we were able to successfully identify the presence of various attacks.

  8. Three-dimensional ocean sensor networks: A survey

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Liu, Yingjian; Guo, Zhongwen

    2012-12-01

    The past decade has seen a growing interest in ocean sensor networks because of their wide applications in marine research, oceanography, ocean monitoring, offshore exploration, and defense or homeland security. Ocean sensor networks are generally formed with various ocean sensors, autonomous underwater vehicles, surface stations, and research vessels. To make ocean sensor network applications viable, efficient communication among all devices and components is crucial. Due to the unique characteristics of underwater acoustic channels and the complex deployment environment in three dimensional (3D) ocean spaces, new efficient and reliable communication and networking protocols are needed in design of ocean sensor networks. In this paper, we aim to provide an overview of the most recent advances in network design principles for 3D ocean sensor networks, with focuses on deployment, localization, topology design, and position-based routing in 3D ocean spaces.

  9. Wide area sensor network

    NASA Astrophysics Data System (ADS)

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

    2006-05-01

    The technical concept for this project has existed since the Chernobyl accident in 1986. A host of Eastern European nations have developed countrywide grid of sensors to monitor airborne radiation. The objective is to build a radiological sensor network for real-time monitoring of environmental radiation levels in order to provide data for warning, and consequentially the assessment of a nuclear event. A network of radiation measuring equipment consisting of gamma, neutron, alpha, and beta counters would be distributed over a large area (preferably on fire station roof tops) and connected by a wireless network to the emergency response center. The networks would be deployed in urban environments and would supply first responders and federal augmentation teams (including those from the U.S. Departments of Energy, Defense, Justice, and Homeland Security) with detailed, accurate information regarding the transport of radioactive environmental contaminants, so the agencies can provide a safe and effective response. A networked sensor capability would be developed, with fixed sensors deployed at key locations and in sufficient numbers, to provide adequate coverage for early warning, and input to post-event emergency response. An overall system description and specification will be provided, including detector characteristics, communication protocols, infrastructure and maintenance requirements, and operation procedures. The system/network can be designed for a specifically identified urban area, or for a general urban area scalable to cities of specified size. Data collected via the network will be transmitted directly to the appropriate emergency response center and shared with multiple agencies via the Internet or an Intranet. The data collected will be managed using commercial off - the - shelf Geographical Information System (GIS). The data will be stored in a database and the GIS software will aid in analysis and management of the data. Unique features of the

  10. Wireless sensor network

    NASA Astrophysics Data System (ADS)

    Perotti, Jose M.; Lucena, Angel R.; Mullenix, Pamela A.; Mata, Carlos T.

    2006-05-01

    Current and future requirements of aerospace sensors and transducers demand the design and development of a new family of sensing devices, with emphasis on reduced weight, power consumption, and physical size. This new generation of sensors and transducers will possess a certain degree of intelligence in order to provide the end user with critical data in a more efficient manner. Communication between networks of traditional or next-generation sensors can be accomplished by a Wireless Sensor Network (WSN) developed by NASA's Instrumentation Branch and ASRC Aerospace Corporation at Kennedy Space Center (KSC), consisting of at least one central station and several remote stations and their associated software. The central station is application-dependent and can be implemented on different computer hardware, including industrial, handheld, or PC-104 single-board computers, on a variety of operating systems: embedded Windows, Linux, VxWorks, etc. The central stations and remote stations share a similar radio frequency (RF) core module hardware that is modular in design. The main components of the remote stations are an RF core module, a sensor interface module, batteries, and a power management module. These modules are stackable, and a common bus provides the flexibility to stack other modules for additional memory, increased processing, etc. WSN can automatically reconfigure to an alternate frequency if interference is encountered during operation. In addition, the base station will autonomously search for a remote station that was perceived to be lost, using relay stations and alternate frequencies. Several wireless remote-station types were developed and tested in the laboratory to support different sensing technologies, such as resistive temperature devices, silicon diodes, strain gauges, pressure transducers, and hydrogen leak detectors.

  11. remote sensor network

    NASA Astrophysics Data System (ADS)

    von Unold, Georg; Junker, Astrid; Altmann, Thomas

    2016-04-01

    High-throughput (HT) plant phenotyping systems enable the quantitative analysis of a variety of plant features in a fully automated fashion. The comprehensive phenomics infrastructure at IPK comprises three LemnaTec conveyor belt-based (plant-to-sensor) systems for the simultaneous analysis of large numbers of individual plants of different sizes. For monitoring of environmental conditions within the plant growth area and soil conditions in individual pots, highly modular and flexible remote sensing devices are required. We present the architecture of a wireless sensor network implemented in the HT plant phenotyping systems at IPK in the frame of the German Plant Phenotyping Network (DPPN). This system comprises 350 soil monitoring modules, each measuring water content, water matrix potential, temperature and electric conductivity. Furthermore small and large sensor platforms enable the continuous monitoring of environmental parameters such as incident photosynthetic active radiation, total radiation balance, relative humidity and CO2 concentration and more. Finally we present an introduction into data management and maintenance."

  12. Underwater Sensor Nodes and Networks

    PubMed Central

    Lloret, Jaime

    2013-01-01

    Sensor technology has matured enough to be used in any type of environment. The appearance of new physical sensors has increased the range of environmental parameters for gathering data. Because of the huge amount of unexploited resources in the ocean environment, there is a need of new research in the field of sensors and sensor networks. This special issue is focused on collecting recent advances on underwater sensors and underwater sensor networks in order to measure, monitor, surveillance of and control of underwater environments. On the one hand, from the sensor node perspective, we will see works related with the deployment of physical sensors, development of sensor nodes and transceivers for sensor nodes, sensor measurement analysis and several issues such as layer 1 and 2 protocols for underwater communication and sensor localization and positioning systems. On the other hand, from the sensor network perspective, we will see several architectures and protocols for underwater environments and analysis concerning sensor network measurements. Both sides will provide us a complete view of last scientific advances in this research field. PMID:24013489

  13. Estimating propagation velocity through a surface acoustic wave sensor

    DOEpatents

    Xu, Wenyuan; Huizinga, John S.

    2010-03-16

    Techniques are described for estimating the propagation velocity through a surface acoustic wave sensor. In particular, techniques which measure and exploit a proper segment of phase frequency response of the surface acoustic wave sensor are described for use as a basis of bacterial detection by the sensor. As described, use of velocity estimation based on a proper segment of phase frequency response has advantages over conventional techniques that use phase shift as the basis for detection.

  14. Sensitive acoustic vibration sensor using single-mode fiber tapers.

    PubMed

    Li, Yi; Wang, Xiaozhen; Bao, Xiaoyi

    2011-05-01

    Optical fiber sensors are a good alternative to piezoelectric devices in electromagnetic sensitive environments. In this study, we reported a fiber acoustic sensor based on single-mode fiber (SMF) tapers. The fiber taper is used as the sensing arm in a Mach-Zehnder interferometer. Benefiting from their micrometer dimensions, fiber tapers have shown higher sensitivities to the acoustic vibrations than SMFs. Under the same conditions, the thinnest fiber taper in this report, with a diameter of 1.7 µm, shows a 20 dB improvement in the signal to noise ratio as compared to that of an SMF. This acoustic vibration sensor can detect the acoustic waves over the frequencies of 30 Hz-40 kHz, which is limited by the acoustic wave generator in experiments. We also discussed the phase changes of fiber tapers with different diameters under acoustic vibrations.

  15. Cloaking of an acoustic sensor using scattering cancellation

    NASA Astrophysics Data System (ADS)

    Guild, Matthew D.; Alù, Andrea; Haberman, Michael R.

    2014-07-01

    In this Letter, a bilaminate acoustic cloak designed using scattering cancellation methods is applied to the case of an acoustic sensor consisting of a hollow piezoelectric shell with mechanical absorption. The bilaminate cloak provides 20-50 dB reduction in scattering strength relative to the uncloaked configuration over the typical range of operation for an acoustic sensor, retains its ability to sensing acoustic pressure signals, and remains within the physical bounds of a passive absorber. Further, the cloak is shown to increase the range of frequencies over which there is nearly perfect phase fidelity between the acoustic signal and the voltage generated by the sensor. The feasibility of achieving the necessary fluid layer properties is demonstrated using sonic crystals with the use of readily available acoustic materials.

  16. Optimizing Voided Piezoelectric Polymers For Acoustic Sensors

    NASA Astrophysics Data System (ADS)

    Arvelo, Juan I.

    2009-07-01

    Polymer piezoelectric materials offer lower density and more flexibility than piezoelectric ceramics for applications where rugged and lightweight acoustic sensors are required. This paper discusses constraints imposed by material stiffness and dielectric constants and aims to derive a generalized closed-form solution for optimizing charged foamed polymers. Optimized solutions are reached in the limits of very large and small void fraction and permittivity ratio. The permittivity ratio is the ratio of the dielectric constants of the polymer and the material that fills the voids. Demonstrations indicate that, in the oblique asymptote, the optimized void fraction becomes equivalent to the permittivity ratio. This effort was conducted under the auspices of the Undersea Warfare Business Area (UWBA) Independent Research & Development (IRAD) Board of the Johns Hopkins University Applied Physics Laboratory (JHU/APL).

  17. High-temperature bulk acoustic wave sensors

    NASA Astrophysics Data System (ADS)

    Fritze, Holger

    2011-01-01

    Piezoelectric crystals like langasite (La3Ga5SiO14, LGS) and gallium orthophosphate (GaPO4) exhibit piezoelectrically excited bulk acoustic waves at temperatures of up to at least 1450 °C and 900 °C, respectively. Consequently, resonant sensors based on those materials enable new sensing approaches. Thereby, resonant high-temperature microbalances are of particular interest. They correlate very small mass changes during film deposition onto resonators or gas composition-dependent stoichiometry changes of thin films already deposited onto the resonators with the resonance frequency shift of such devices. Consequently, the objective of the work is to review the high-temperature properties, the operation limits and the measurement principles of such resonators. The electromechanical properties of high-temperature bulk acoustic wave resonators such as mechanical stiffness, piezoelectric and dielectric constant, effective viscosity and electrical conductivity are described using a one-dimensional physical model and determined accurately up to temperatures as close as possible to their ultimate limit. Insights from defect chemical models are correlated with the electromechanical properties of the resonators. Thereby, crucial properties for stable operation as a sensor under harsh conditions are identified to be the formation of oxygen vacancies and the bulk conductivity. Operation limits concerning temperature, oxygen partial pressure and water vapor pressure are given. Further, application-relevant aspects such as temperature coefficients, temperature compensation and mass sensitivity are evaluated. In addition, approximations are introduced which make the exact model handy for routine data evaluation. An equivalent electrical circuit for high-temperature resonator devices is derived based on the one-dimensional physical model. Low- and high-temperature approximations are introduced. Thereby, the structure of the equivalent circuit corresponds to the Butterworth

  18. Report on the acoustic network arctic deployment

    NASA Astrophysics Data System (ADS)

    Johnson, Mark; Herold, David; Catipovic, Josko

    1995-03-01

    This report describes the March 1994 Arctic deployment undertaken by the Acoustic Telemetry Group of WHOI. The deployment was a part of the 1994 Sea Ice Mechanics Initiative (SIMI) project and was based at the west SIMI camp, approximately 150 Nautical miles north-east of Prudhoe Bay, Alaska. The goal of the deployment was to install a network of six high-performance acoustic modems, developed at WHOI, and to obtain a data set demonstrating the communications and acoustic monitoring capabilities of the network. The six modems in the network were deployed over an area of 22 square km and communicated via radio Ethernet with a computer at the SIMI camp. Each modem had a global positioning system, an acoustic source and an 8 element receiving array. The network was operated in a round-robin broadcast mode (i.e., each modern in turn transmitted a packet of data while the others received). The transmissions were 5000 bits-per-second QPSK with a 15kHz carrier. An extensive data set including raw acoustic data, source localization information, and modem position was collected during the deployment. An additional function of the acoustic network was to communicate with, and track, the Odyssey, an autonomous underwater vehicle operated by the Mff group at the SIMI camp. To this end, the Odyssey was equipped with a Datasonics modem configured for periodic QPSK transmission to the network. A data set was obtained from which both the up-link communication and localization capabilities of the network can be determined.

  19. Packaging of an iron-gallium (Galfenol) nanowire acoustic sensor

    NASA Astrophysics Data System (ADS)

    Jain, Rupal; McCluskey, F. Patrick; Flatau, Alison B.; Stadler, Bethanie J. H.

    2007-04-01

    Packaging is a key issue for the effective working of an iron-gallium (Galfenol) nanowire acoustic sensor for underwater applications. The nanowire acoustic sensor incorporates cilia-like nanowires made of galfenol, a magnetostrictive material, which responds by changing magnetic flux flowing through it due to bending stress induced by the incoming acoustic waves. This stress induced change in the magnetic flux density is detected by a GMR sensor. An effective package should provide a suitably protective environment to these nanowires, while allowing sound waves to reach the nanowires with a minimum level of attenuation. A bio-inspired MEMS package has been designed, analogous to a human-ear cochlea for the nanowire acoustic sensor. In this paper, the process sequence for fabrication of the package is presented. Unlike other microphones, the nanoacoustic sensor has been enclosed in a cavity to allow free movement of the nanowires in a fluid medium. The package also ensures resisting ingression of sea water and salt ions to prevent the corrosion of sensor components. The effect of package material on sensor performance was investigated by conducting experiments on acoustic impedance and attenuation characteristics, and salt water absorption properties. The package filled with silicone oil and molded with polydimethylsiloxane (PDMS) is observed to outperform other packages at all frequencies by minimizing attenuation of the acoustic waves.

  20. An efficient and reliable geographic routing protocol based on partial network coding for underwater sensor networks.

    PubMed

    Hao, Kun; Jin, Zhigang; Shen, Haifeng; Wang, Ying

    2015-01-01

    Efficient routing protocols for data packet delivery are crucial to underwater sensor networks (UWSNs). However, communication in UWSNs is a challenging task because of the characteristics of the acoustic channel. Network coding is a promising technique for efficient data packet delivery thanks to the broadcast nature of acoustic channels and the relatively high computation capabilities of the sensor nodes. In this work, we present GPNC, a novel geographic routing protocol for UWSNs that incorporates partial network coding to encode data packets and uses sensor nodes' location information to greedily forward data packets to sink nodes. GPNC can effectively reduce network delays and retransmissions of redundant packets causing additional network energy consumption. Simulation results show that GPNC can significantly improve network throughput and packet delivery ratio, while reducing energy consumption and network latency when compared with other routing protocols.

  1. An Efficient and Reliable Geographic Routing Protocol Based on Partial Network Coding for Underwater Sensor Networks

    PubMed Central

    Hao, Kun; Jin, Zhigang; Shen, Haifeng; Wang, Ying

    2015-01-01

    Efficient routing protocols for data packet delivery are crucial to underwater sensor networks (UWSNs). However, communication in UWSNs is a challenging task because of the characteristics of the acoustic channel. Network coding is a promising technique for efficient data packet delivery thanks to the broadcast nature of acoustic channels and the relatively high computation capabilities of the sensor nodes. In this work, we present GPNC, a novel geographic routing protocol for UWSNs that incorporates partial network coding to encode data packets and uses sensor nodes’ location information to greedily forward data packets to sink nodes. GPNC can effectively reduce network delays and retransmissions of redundant packets causing additional network energy consumption. Simulation results show that GPNC can significantly improve network throughput and packet delivery ratio, while reducing energy consumption and network latency when compared with other routing protocols. PMID:26029955

  2. Fiber-optic acoustic-emission sensors and detection

    NASA Astrophysics Data System (ADS)

    Borinski, Jason W.; Clark, Richard L., Jr.; Furrow, A. Paige C.; Duke, John C., Jr.; Horne, Michael R.

    2000-05-01

    Optical fiber sensors are rapidly emerging as viable alternatives to piezoelectric devices as effective means of detecting and quantifying acoustic emission (AE). Compared to traditional piezoelectric-based sensors, optical fiber sensors offer much smaller size, reduced weight, ability to operate at temperatures up to 2000 degrees Celsius, immunity to electromagnetic interference, resistance to corrosive environments, inherent safety within flammable environments, and the ability to multiplex multiple sensors on a single fiber. The authors have investigated low-profile fiber optic- based AE sensors for non-destructive evaluation (NDE) systems. In particular, broadband optical fiber sensors were developed for monitoring acoustic emission for NDE of pressurized composite vessels. The authors conducted experiments by surface attaching sensors to aluminum compact tension specimens using a piezoelectric transducer as a reference sensor. Both the fiber optic and piezoelectric sensors accurately measured a representative acoustic event. The response of the fiber optic AE sensors were also compared to existing piezoelectric sensors during pencil lead break tests on an aluminum panel. The results indicate that optical fiber AE sensors can be used as highly sensitive transducers in many applications where conventional piezoelectric transducers are not suited.

  3. An ontology for sensor networks

    NASA Astrophysics Data System (ADS)

    Compton, Michael; Neuhaus, Holger; Bermudez, Luis; Cox, Simon

    2010-05-01

    Sensors and networks of sensors are important ways of monitoring and digitizing reality. As the number and size of sensor networks grows, so too does the amount of data collected. Users of such networks typically need to discover the sensors and data that fit their needs without necessarily understanding the complexities of the network itself. The burden on users is eased if the network and its data are expressed in terms of concepts familiar to the users and their job functions, rather than in terms of the network or how it was designed. Furthermore, the task of collecting and combining data from multiple sensor networks is made easier if metadata about the data and the networks is stored in a format and conceptual models that is amenable to machine reasoning and inference. While the OGC's (Open Geospatial Consortium) SWE (Sensor Web Enablement) standards provide for the description and access to data and metadata for sensors, they do not provide facilities for abstraction, categorization, and reasoning consistent with standard technologies. Once sensors and networks are described using rich semantics (that is, by using logic to describe the sensors, the domain of interest, and the measurements) then reasoning and classification can be used to analyse and categorise data, relate measurements with similar information content, and manage, query and task sensors. This will enable types of automated processing and logical assurance built on OGC standards. The W3C SSN-XG (Semantic Sensor Networks Incubator Group) is producing a generic ontology to describe sensors, their environment and the measurements they make. The ontology provides definitions for the structure of sensors and observations, leaving the details of the observed domain unspecified. This allows abstract representations of real world entities, which are not observed directly but through their observable qualities. Domain semantics, units of measurement, time and time series, and location and mobility

  4. Distributed estimation of sensors position in underwater wireless sensor network

    NASA Astrophysics Data System (ADS)

    Zandi, Rahman; Kamarei, Mahmoud; Amiri, Hadi

    2016-05-01

    In this paper, a localisation method for determining the position of fixed sensor nodes in an underwater wireless sensor network (UWSN) is introduced. In this simple and range-free scheme, the node localisation is achieved by utilising an autonomous underwater vehicle (AUV) that transverses through the network deployment area, and that periodically emits a message block via four directional acoustic beams. A message block contains the actual known AUV position as well as a directional dependent marker that allows a node to identify the respective transmit beam. The beams form a fixed angle with the AUV body. If a node passively receives message blocks, it could calculate the arithmetic mean of the coordinates existing in each messages sequence, to find coordinates at two different time instants via two different successive beams. The node position can be derived from the two computed positions of the AUV. The major advantage of the proposed localisation algorithm is that it is silent, which leads to energy efficiency for sensor nodes. The proposed method does not require any synchronisation among the nodes owing to being silent. Simulation results, using MATLAB, demonstrated that the proposed method had better performance than other similar AUV-based localisation methods in terms of the rates of well-localised sensor nodes and positional root mean square error.

  5. Artillery localization using networked wireless ground sensors

    NASA Astrophysics Data System (ADS)

    Swanson, David C.

    2002-08-01

    This paper presents the results of an installation of four acoustic/seismic ground sensors built using COTS computers and networking gear and operating on a continuous basis at Yuma Proving Grounds, Arizona. A description of the design can be found as well, which is essentially a Windows 2000 PC with 24-bit data acquisition, GPS timing, and environmental sensors for wind and temperature. A 4-element square acoustic array 1.8m on a side can be used to detect the time and angle of arrival of the muzzle blast and the impact explosion. A 3-component geophone allows the seismic wave direction to be estimated. The 8th channel of the 24-bit data acquisition system has a 1-pulse-per-second time signal from the GPS. This allows acoustic/seismic 'snapshots' to be coherently related from multiple disconnected ground sensor nodes. COTS 2.4 GHz frequency hopping radios (802.11 standard) are used with either omni or yagi antennas depending on the location on the range. Localization of the artillery or impact can be done by using the time and angle of arrival of the waves at 2 or more ground sensor locations. However, this straightforward analysis can be significantly complicated by weather and wind noise and is also the subject of another research contract. This work will present a general description of the COTS ground sensor installation, show example data autonomously collected including agent-based atmospheric data, and share some of the lessons learned from operating a Windows 2000 based system continuously outdoors.

  6. Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors.

    PubMed

    Felis, Ivan; Martínez-Mora, Juan Antonio; Ardid, Miguel

    2016-01-01

    Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. With the aim of optimizing the sensor system, a test bench for the characterization of the sensors has been developed. The sensor response for different piezoelectric materials, geometries, matching layers, and backing layers have been measured and contrasted with FEM simulations and analytical models. The results of these studies lead us to have a design criterion for the construction of specific sensors for the next generation of dark matter bubble chamber detectors (250 L). PMID:27294937

  7. Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors.

    PubMed

    Felis, Ivan; Martínez-Mora, Juan Antonio; Ardid, Miguel

    2016-06-10

    Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. With the aim of optimizing the sensor system, a test bench for the characterization of the sensors has been developed. The sensor response for different piezoelectric materials, geometries, matching layers, and backing layers have been measured and contrasted with FEM simulations and analytical models. The results of these studies lead us to have a design criterion for the construction of specific sensors for the next generation of dark matter bubble chamber detectors (250 L).

  8. Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors

    PubMed Central

    Felis, Ivan; Martínez-Mora, Juan Antonio; Ardid, Miguel

    2016-01-01

    Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. With the aim of optimizing the sensor system, a test bench for the characterization of the sensors has been developed. The sensor response for different piezoelectric materials, geometries, matching layers, and backing layers have been measured and contrasted with FEM simulations and analytical models. The results of these studies lead us to have a design criterion for the construction of specific sensors for the next generation of dark matter bubble chamber detectors (250 L). PMID:27294937

  9. Speaker verification using combined acoustic and EM sensor signal processing

    SciTech Connect

    Ng, L C; Gable, T J; Holzrichter, J F

    2000-11-10

    Low Power EM radar-like sensors have made it possible to measure properties of the human speech production system in real-time, without acoustic interference. This greatly enhances the quality and quantity of information for many speech related applications. See Holzrichter, Burnett, Ng, and Lea, J. Acoustic. SOC. Am . 103 ( 1) 622 (1998). By combining the Glottal-EM-Sensor (GEMS) with the Acoustic-signals, we've demonstrated an almost 10 fold reduction in error rates from a speaker verification system experiment under a moderate noisy environment (-10dB).

  10. Low Bandwidth Vocoding using EM Sensor and Acoustic Signal Processing

    SciTech Connect

    Ng, L C; Holzrichter, J F; Larson, P E

    2001-10-25

    Low-power EM radar-like sensors have made it possible to measure properties of the human speech production system in real-time, without acoustic interference [1]. By combining these data with the corresponding acoustic signal, we've demonstrated an almost 10-fold bandwidth reduction in speech compression, compared to a standard 2.4 kbps LPC10 protocol used in the STU-III (Secure Terminal Unit, third generation) telephone. This paper describes a potential EM sensor/acoustic based vocoder implementation.

  11. Localization of acoustic sensors from passive Green's function estimation.

    PubMed

    Nowakowski, Thibault; Daudet, Laurent; de Rosny, Julien

    2015-11-01

    A number of methods have recently been developed for passive localization of acoustic sensors, based on the assumption that the acoustic field is diffuse. This article presents the more general case of equipartition fields, which takes into account reflections off boundaries and/or scatterers. After a thorough discussion on the fundamental differences between the diffuse and equipartition models, it is shown that the method is more robust when dealing with wideband noise sources. Finally, experimental results show, for two types of boundary conditions, that this approach is especially relevant when acoustic sensors are close to boundaries.

  12. Crack Propagation Analysis Using Acoustic Emission Sensors for Structural Health Monitoring Systems

    DOE PAGES

    Kral, Zachary; Horn, Walter; Steck, James

    2013-01-01

    Aerospace systems are expected to remain in service well beyond their designed life. Consequently, maintenance is an important issue. A novel method of implementing artificial neural networks and acoustic emission sensors to form a structural health monitoring (SHM) system for aerospace inspection routines was the focus of this research. Simple structural elements, consisting of flat aluminum plates of AL 2024-T3, were subjected to increasing static tensile loading. As the loading increased, designed cracks extended in length, releasing strain waves in the process. Strain wave signals, measured by acoustic emission sensors, were further analyzed in post-processing by artificial neural networks (ANN).more » Several experiments were performed to determine the severity and location of the crack extensions in the structure. ANNs were trained on a portion of the data acquired by the sensors and the ANNs were then validated with the remaining data. The combination of a system of acoustic emission sensors, and an ANN could determine crack extension accurately. The difference between predicted and actual crack extensions was determined to be between 0.004 in. and 0.015 in. with 95% confidence. These ANNs, coupled with acoustic emission sensors, showed promise for the creation of an SHM system for aerospace systems.« less

  13. Crack Propagation Analysis Using Acoustic Emission Sensors for Structural Health Monitoring Systems

    PubMed Central

    Horn, Walter; Steck, James

    2013-01-01

    Aerospace systems are expected to remain in service well beyond their designed life. Consequently, maintenance is an important issue. A novel method of implementing artificial neural networks and acoustic emission sensors to form a structural health monitoring (SHM) system for aerospace inspection routines was the focus of this research. Simple structural elements, consisting of flat aluminum plates of AL 2024-T3, were subjected to increasing static tensile loading. As the loading increased, designed cracks extended in length, releasing strain waves in the process. Strain wave signals, measured by acoustic emission sensors, were further analyzed in post-processing by artificial neural networks (ANN). Several experiments were performed to determine the severity and location of the crack extensions in the structure. ANNs were trained on a portion of the data acquired by the sensors and the ANNs were then validated with the remaining data. The combination of a system of acoustic emission sensors, and an ANN could determine crack extension accurately. The difference between predicted and actual crack extensions was determined to be between 0.004 in. and 0.015 in. with 95% confidence. These ANNs, coupled with acoustic emission sensors, showed promise for the creation of an SHM system for aerospace systems. PMID:24023536

  14. Crack propagation analysis using acoustic emission sensors for structural health monitoring systems.

    PubMed

    Kral, Zachary; Horn, Walter; Steck, James

    2013-01-01

    Aerospace systems are expected to remain in service well beyond their designed life. Consequently, maintenance is an important issue. A novel method of implementing artificial neural networks and acoustic emission sensors to form a structural health monitoring (SHM) system for aerospace inspection routines was the focus of this research. Simple structural elements, consisting of flat aluminum plates of AL 2024-T3, were subjected to increasing static tensile loading. As the loading increased, designed cracks extended in length, releasing strain waves in the process. Strain wave signals, measured by acoustic emission sensors, were further analyzed in post-processing by artificial neural networks (ANN). Several experiments were performed to determine the severity and location of the crack extensions in the structure. ANNs were trained on a portion of the data acquired by the sensors and the ANNs were then validated with the remaining data. The combination of a system of acoustic emission sensors, and an ANN could determine crack extension accurately. The difference between predicted and actual crack extensions was determined to be between 0.004 in. and 0.015 in. with 95% confidence. These ANNs, coupled with acoustic emission sensors, showed promise for the creation of an SHM system for aerospace systems. PMID:24023536

  15. Development of combined Opto-Acoustical sensor Modules

    NASA Astrophysics Data System (ADS)

    Enzenhöfer, A.; Anton, G.; Graf, K.; Hößl, J.; Katz, U.; Lahmann, R.; Neff, M.; Richardt, C.

    2012-01-01

    The faint fluxes of cosmic neutrinos expected at very high energies require large instrumented detector volumes. The necessary volumes in combination with a sufficient shielding against background constitute forbidding and complex environments (e.g. the deep sea) as sites for neutrino telescopes. To withstand these environments and to assure the data quality, the sensors have to be reliable and their operation has to be as simple as possible. A compact sensor module design including all necessary components for data acquisition and module calibration would simplify the detector mechanics and ensures the long term operability of the detector. The compact design discussed here combines optical and acoustical sensors inside one module, therefore reducing electronics and additional external instruments for calibration purposes. In this design the acoustical sensor is primary used for acoustic positioning of the module. The module may also be used for acoustic particle detection and marine science if an appropriate acoustical sensor is chosen.First tests of this design are promising concerning the task of calibration. To expand the field of application also towards acoustic particle detection further improvements concerning electromagnetic shielding and adaptation of the single components are necessary.

  16. An Overview of the Sensor Networks

    NASA Astrophysics Data System (ADS)

    Ikegami, Tetsushi

    Recently, the sensor network technology attracts a great deal of attention achieving a safe and comfortable ubiquitous society. The sensor networks are already used in environment and disaster monitoring, medical care, logistics and transportation. This paper aimed to understand the outline of the sensor network technology centering on the wireless sensor network technology.

  17. Constraining shallow slip and tsunami excitation in megathrust ruptures using seismic and ocean acoustic waves recorded on ocean-bottom sensor networks

    NASA Astrophysics Data System (ADS)

    Kozdon, Jeremy E.; Dunham, Eric M.

    2014-06-01

    Great earthquakes along subduction-zone plate boundaries, like the 2011 magnitude 9.0 Tohoku-Oki, Japan, event, deform the seafloor to generate massive tsunamis. Tsunami wave heights near shore are greatest when excitation occurs far offshore near the trench, where water depths are greatest and fault slip is shallow. The Tohoku event, featuring over 30 m of slip near the trench, exemplifies this hazard. Unfortunately the rupture process that far offshore is poorly constrained with land-based geodetic and even most seafloor deformation measurements, and seismic inferences of shallow slip are often nonunique. Here we demonstrate, through dynamic rupture simulations of the Tohoku event, that long-period guided waves in the ocean (specifically, leaking oceanic P-wave modes known as PL waves) can resolve the shallow rupture process and tsunami excitation near the trench. With predicted pressure changes of ∼0.1-1 MPa along most of the seafloor landward of the trench, and periods of several seconds, these PL waves should be observable with ocean-bottom pressure sensors and/or seismometers. With cabled sensor networks like those being deployed offshore Japan and in other subduction zones, these waves could be used to rapidly quantify shallow slip and near-trench seafloor uplift and improve local tsunami early warning systems.

  18. Packaging of an iron-gallium nanowire acoustic sensor

    NASA Astrophysics Data System (ADS)

    DiSabatino, Ronald J., Jr.; McCluskey, F. Patrick; Flatau, Alison B.; Stadler, Bethanie J. H.

    2006-03-01

    The development of packaging for an underwater acoustic sensor is a more complex task than package design for a typical microelectronic device because of the need to simultaneously protect the device from the environment while allowing interaction with it. The goal of this work is to create an underwater acoustic sensor package that will allow sound transmission to the sensor while keeping out moisture and salt ions. A bio-inspired package, based on the hearing mechanisms in fish and other aquatic animals, has been developed for this purpose. The package will ensure reliability in the underwater environment while not interfering with the transmission of sound. The sensor design incorporates magnetostrictive iron-gallium (Galfenol) nanowires. Arrays of cilia-like nanowires mechanically respond to incoming sound waves, thus creating magnetic fields that are sensed by a GMR sensor. The package is designed to contain the nanowires in a fluid medium, leaving them free to move. Materials matching the acoustic impedance of seawater are incorporated to allow sound to penetrate the package. Acoustic properties of various materials were investigated using scanning acoustic microscopy for this application. A fabrication process for the package is presented. The fabrication incorporates a room temperature soldering process that will not harm the sensor during the bonding of package components.

  19. Monitoring of acoustic emission activity using thin wafer piezoelectric sensors

    NASA Astrophysics Data System (ADS)

    Trujillo, Blaine; Zagrai, Andrei; Meisner, Daniel; Momeni, Sepand

    2014-03-01

    Acoustic emission (AE) is a well-known technique for monitoring onset and propagation of material damage. The technique has demonstrated utility in assessment of metallic and composite materials in applications ranging from civil structures to aerospace vehicles. While over the course of few decades AE hardware has changed dramatically with the sensors experiencing little changes. A traditional acoustic emission sensor solution utilizes a thickness resonance of the internal piezoelectric element which, coupled with internal amplification circuit, results in relatively large sensor footprint. Thin wafer piezoelectric sensors are small and unobtrusive, but they have seen limited AE applications due to low signal-to-noise ratio and other operation difficulties. In this contribution, issues and possible solutions pertaining to the utility of thin wafer piezoelectrics as AE sensors are discussed. Results of AE monitoring of fatigue damage using thin wafer piezoelectric and conventional AE sensors are presented.

  20. Optimization of Surface Acoustic Wave-Based Rate Sensors

    PubMed Central

    Xu, Fangqian; Wang, Wen; Shao, Xiuting; Liu, Xinlu; Liang, Yong

    2015-01-01

    The optimization of an surface acoustic wave (SAW)-based rate sensor incorporating metallic dot arrays was performed by using the approach of partial-wave analysis in layered media. The optimal sensor chip designs, including the material choice of piezoelectric crystals and metallic dots, dot thickness, and sensor operation frequency were determined theoretically. The theoretical predictions were confirmed experimentally by using the developed SAW sensor composed of differential delay line-oscillators and a metallic dot array deposited along the acoustic wave propagation path of the SAW delay lines. A significant improvement in sensor sensitivity was achieved in the case of 128° YX LiNbO3, and a thicker Au dot array, and low operation frequency were used to structure the sensor. PMID:26473865

  1. Wireless Sensor Networks: Monitoring and Control

    SciTech Connect

    Hastbacka, Mildred; Ponoum, Ratcharit; Bouza, Antonio

    2013-05-31

    The article discusses wireless sensor technologies for building energy monitoring and control. This article, also, addresses wireless sensor networks as well as benefits and challenges of using wireless sensors. The energy savings and market potential of wireless sensors are reviewed.

  2. Networked Sensor Arrays

    SciTech Connect

    R. J. Tighe

    2002-10-01

    A set of independent radiation sensors, coupled with real-time data telemetry, offers the opportunity to run correlation algorithms for the sensor array as well as to incorporate non-radiological data into the system. This may enhance the overall sensitivity of the sensors and provide an opportunity to project the location of a source within the array. In collaboration with Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories (SNL), we have conducted field experiments to test a prototype system. Combining the outputs of a set of distributed sensors permits the correlation that the independent sensor outputs. Combined with additional information such as traffic patterns and velocities, this can reduce random/false detections and enhance detection capability. The principle components of such a system include: (1) A set of radiation sensors. These may be of varying type and complexity, including gamma and/or neutron detectors, gross count and spectral-capable sensors, and low to high energy-resolution sensors. (2) A set of non-radiation sensors. These may include sensors such as vehicle presence and imaging sensors. (3) A communications architecture for near real-time telemetry. Depending upon existing infrastructure and bandwidth requirements, this may be a radio or hard-wire based system. (4) A central command console to pole the sensors, correlate their output, and display the data in a meaningful form to the system operator. Both sensitivity and selectivity are important considerations when evaluating the performance of a detection system. Depending on the application, the optimization of sensitivity as well as the rejection of ''nuisance'' radioactive sources may or may not be critical.

  3. Modeling of a Surface Acoustic Wave Strain Sensor

    NASA Technical Reports Server (NTRS)

    Wilson, W. C.; Atkinson, Gary M.

    2010-01-01

    NASA Langley Research Center is investigating Surface Acoustic Wave (SAW) sensor technology for harsh environments aimed at aerospace applications. To aid in development of sensors a model of a SAW strain sensor has been developed. The new model extends the modified matrix method to include the response of Orthogonal Frequency Coded (OFC) reflectors and the response of SAW devices to strain. These results show that the model accurately captures the strain response of a SAW sensor on a Langasite substrate. The results of the model of a SAW Strain Sensor on Langasite are presented

  4. Biomimetic smart sensors for autonomous robotic behavior I: acoustic processing

    NASA Astrophysics Data System (ADS)

    Deligeorges, Socrates; Xue, Shuwan; Soloway, Aaron; Lichtenstein, Lee; Gore, Tyler; Hubbard, Allyn

    2009-05-01

    Robotics are rapidly becoming an integral tool on the battlefield and in homeland security, replacing humans in hazardous conditions. To enhance the effectiveness of robotic assets and their interaction with human operators, smart sensors are required to give more autonomous function to robotic platforms. Biologically inspired sensors are an essential part of this development of autonomous behavior and can increase both capability and performance of robotic systems. Smart, biologically inspired acoustic sensors have the potential to extend autonomous capabilities of robotic platforms to include sniper detection, vehicle tracking, personnel detection, and general acoustic monitoring. The key to enabling these capabilities is biomimetic acoustic processing using a time domain processing method based on the neural structures of the mammalian auditory system. These biologically inspired algorithms replicate the extremely adaptive processing of the auditory system yielding high sensitivity over broad dynamic range. The algorithms provide tremendous robustness in noisy and echoic spaces; properties necessary for autonomous function in real world acoustic environments. These biomimetic acoustic algorithms also provide highly accurate localization of both persistent and transient sounds over a wide frequency range, using baselines on the order of only inches. A specialized smart sensor has been developed to interface with an iRobot Packbot® platform specifically to enhance its autonomous behaviors in response to personnel and gunfire. The low power, highly parallel biomimetic processor, in conjunction with a biomimetic vestibular system (discussed in the companion paper), has shown the system's autonomous response to gunfire in complicated acoustic environments to be highly effective.

  5. Network compensation for missing sensors

    NASA Technical Reports Server (NTRS)

    Ahumada, Albert J., Jr.; Mulligan, Jeffrey B.

    1991-01-01

    A network learning translation invariance algorithm to compute interpolation functions is presented. This algorithm with one fixed receptive field can construct a linear transformation compensating for gain changes, sensor position jitter, and sensor loss when there are enough remaining sensors to adequately sample the input images. However, when the images are undersampled and complete compensation is not possible, the algorithm need to be modified. For moderate sensor losses, the algorithm works if the transformation weight adjustment is restricted to the weights to output units affected by the loss.

  6. All-fiber photoacoustic gas sensor with graphene nano-mechanical resonator as the acoustic detector

    NASA Astrophysics Data System (ADS)

    Yanzhen, Tan; Fan, Yang; Jun, Ma; Hoi Lut, Ho; Wei, Jin

    2015-09-01

    We demonstrate an all-optical-fiber photoacoustic (PA) spectrometric gas sensor with a graphene nano-mechanical resonator as the acoustic detector. The acoustic detection is performed by a miniature ferrule-top nano-mechanical resonator with a ˜100-nm-thick, 2.5-mm-diameter multilayer graphene diaphragm. Experimental investigation showed that the performance of the PA gas sensor can be significantly enhanced by operating at the resonance of the grapheme diaphragm where a lower detection limit of 153 parts-per-billion (ppb) acetylene is achieved. The all-fiber PA sensor which is immune to electromagnetic interference and safe in explosive environments is ideally suited for real-world remote, space-limited applications and for multipoint detection in a multiplexed fiber optic sensor network.

  7. Acoustic sensors in the helmet detect voice and physiology

    NASA Astrophysics Data System (ADS)

    Scanlon, Michael V.

    2003-09-01

    The Army Research Laboratory has developed body-contacting acoustic sensors that detect diverse physiological sounds such as heartbeats and breaths, high quality speech, and activity. These sensors use an acoustic impedance-matching gel contained in a soft, compliant pad to enhance the body borne sounds, yet significantly repel airborne noises due to an acoustic impedance mismatch. The signals from such a sensor can be used as a microphone with embedded physiology, or a dedicated digital signal processor can process packetized data to separate physiological parameters from voice, and log parameter trends for performance surveillance. Acoustic sensors were placed inside soldier helmets to monitor voice, physiology, activity, and situational awareness clues such as bullet shockwaves from sniper activity and explosions. The sensors were also incorporated into firefighter breathing masks, neck and wrist straps, and other protective equipment. Heart rate, breath rate, blood pressure, voice and activity can be derived from these sensors (reports at www.arl.army.mil/acoustics). Having numerous sensors at various locations provides a means for array processing to reduce motion artifacts, calculate pulse transit time for passive blood pressure measurement, and the origin of blunt/penetrating traumas such as ballistic wounding. These types of sensors give us the ability to monitor soldiers and civilian emergency first-responders in demanding environments, and provide vital signs information to assess their health status and how that person is interacting with the environment and mission at hand. The Objective Force Warrior, Scorpion, Land Warrior, Warrior Medic, and other military and civilian programs can potentially benefit from these sensors.

  8. High-sensitivity acoustic sensors from nanofibre webs

    NASA Astrophysics Data System (ADS)

    Lang, Chenhong; Fang, Jian; Shao, Hao; Ding, Xin; Lin, Tong

    2016-03-01

    Considerable interest has been devoted to converting mechanical energy into electricity using polymer nanofibres. In particular, piezoelectric nanofibres produced by electrospinning have shown remarkable mechanical energy-to-electricity conversion ability. However, there is little data for the acoustic-to-electric conversion of electrospun nanofibres. Here we show that electrospun piezoelectric nanofibre webs have a strong acoustic-to-electric conversion ability. Using poly(vinylidene fluoride) as a model polymer and a sensor device that transfers sound directly to the nanofibre layer, we show that the sensor devices can detect low-frequency sound with a sensitivity as high as 266 mV Pa-1. They can precisely distinguish sound waves in low to middle frequency region. These features make them especially suitable for noise detection. Our nanofibre device has more than five times higher sensitivity than a commercial piezoelectric poly(vinylidene fluoride) film device. Electrospun piezoelectric nanofibres may be useful for developing high-performance acoustic sensors.

  9. ECS: efficient communication scheduling for underwater sensor networks.

    PubMed

    Hong, Lu; Hong, Feng; Guo, Zhongwen; Li, Zhengbao

    2011-01-01

    TDMA protocols have attracted a lot of attention for underwater acoustic sensor networks (UWSNs), because of the unique characteristics of acoustic signal propagation such as great energy consumption in transmission, long propagation delay and long communication range. Previous TDMA protocols all allocated transmission time to nodes based on discrete time slots. This paper proposes an efficient continuous time scheduling TDMA protocol (ECS) for UWSNs, including the continuous time based and sender oriented conflict analysis model, the transmission moment allocation algorithm and the distributed topology maintenance algorithm. Simulation results confirm that ECS improves network throughput by 20% on average, compared to existing MAC protocols.

  10. ECS: Efficient Communication Scheduling for Underwater Sensor Networks

    PubMed Central

    Hong, Lu; Hong, Feng; Guo, Zhongwen; Li, Zhengbao

    2011-01-01

    TDMA protocols have attracted a lot of attention for underwater acoustic sensor networks (UWSNs), because of the unique characteristics of acoustic signal propagation such as great energy consumption in transmission, long propagation delay and long communication range. Previous TDMA protocols all allocated transmission time to nodes based on discrete time slots. This paper proposes an efficient continuous time scheduling TDMA protocol (ECS) for UWSNs, including the continuous time based and sender oriented conflict analysis model, the transmission moment allocation algorithm and the distributed topology maintenance algorithm. Simulation results confirm that ECS improves network throughput by 20% on average, compared to existing MAC protocols. PMID:22163775

  11. Dual output acoustic wave sensor for molecular identification

    DOEpatents

    Frye, Gregory C.; Martin, Stephen J.

    1991-01-01

    A method of identification and quantification of absorbed chemical species by measuring changes in both the velocity and the attenuation of an acoustic wave traveling through a thin film into which the chemical species is sorbed. The dual output response provides two independent sensor responses from a single sensing device thereby providing twice as much information as a single output sensor. This dual output technique and analysis allows a single sensor to provide both the concentration and the identity of a chemical species or permits the number of sensors required for mixtures to be reduced by a factor of two.

  12. Crack propagation testing using a YCOB acoustic emission sensor

    NASA Astrophysics Data System (ADS)

    Johnson, Joseph A.; Kim, Kyungrim; Zhang, Shujun; Jiang, Xiaoning

    2014-03-01

    Piezoelectric crystals are popular for passive sensors, such as accelerometers and acoustic emission sensors, due to their robustness and high sensitivity. These sensors are widespread in structural health monitoring among civil and industrial structures, but there is little application in high temperature environments (e.g. > 1000°C) due to the few materials that are capable of operating at elevated temperatures. Most piezoelectric materials suffer from a loss of electric properties above temperatures in the 500-700°C range, but rare earth oxyborate crystals, such as Yttrium calcium oxyborate (YCOB), retain their piezoelectric properties above 1000 °C. Our previous research demonstrated that YCOB can be used to detect transient lamb waves via Hsu-Nielsen tests, which replicate acoustic emission waves, up to 1000°C. In this paper, YCOB piezoelectric acoustic emission sensors were tested for their ability to detect crack progression at elevated temperatures. The sensor was fabricated using a YCOB single crystal and Inconel electrodes and wires. The sensor was mounted onto a stainless steel bar substrate, which was machined to include a pre-crack notch. A dynamic load was induced on the bar with a shaker in order to force the crack to advance along the thickness of the substrate. The obtained raw data was processed and analyzed in the frequency domain and compared to the Lamb wave modes that were evaluated in previous Hsu-Nielsen testing for the substrate.

  13. Sensor network based vehicle classification and license plate identification system

    SciTech Connect

    Frigo, Janette Rose; Brennan, Sean M; Rosten, Edward J; Raby, Eric Y; Kulathumani, Vinod K

    2009-01-01

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

  14. Bio-Inspired Micromechanical Directional Acoustic Sensor

    NASA Astrophysics Data System (ADS)

    Swan, William; Alves, Fabio; Karunasiri, Gamani

    Conventional directional sound sensors employ an array of spatially separated microphones and the direction is determined using arrival times and amplitudes. In nature, insects such as the Ormia ochracea fly can determine the direction of sound using a hearing organ much smaller than the wavelength of sound it detects. The fly's eardrums are mechanically coupled, only separated by about 1 mm, and have remarkable directional sensitivity. A micromechanical sensor based on the fly's hearing system was designed and fabricated on a silicon on insulator (SOI) substrate using MEMS technology. The sensor consists of two 1 mm2 wings connected using a bridge and to the substrate using two torsional legs. The dimensions of the sensor and material stiffness determine the frequency response of the sensor. The vibration of the wings in response to incident sound at the bending resonance was measured using a laser vibrometer and found to be about 1 μm/Pa. The electronic response of the sensor to sound was measured using integrated comb finger capacitors and found to be about 25 V/Pa. The fabricated sensors showed good directional sensitivity. In this talk, the design, fabrication and characteristics of the directional sound sensor will be described. Supported by ONR and TDSI.

  15. Theory for a gas composition sensor based on acoustic properties.

    PubMed

    Phillips, Scott; Dain, Yefim; Lueptow, Richard M

    2003-01-01

    Sound travelling through a gas propagates at different speeds and its intensity attenuates to different degrees depending upon the composition of the gas. Theoretically, a real-time gaseous composition sensor could be based on measuring the sound speed and the acoustic attenuation. To this end, the speed of sound was modelled using standard relations, and the acoustic attenuation was modelled using the theory for vibrational relaxation of gas molecules. The concept for a gas composition sensor is demonstrated theoretically for nitrogen-methane-water and hydrogen-oxygen-water mixtures. For a three-component gas mixture, the measured sound speed and acoustic attenuation each define separate lines in the composition plane of two of the gases. The intersection of the two lines defines the gas composition. It should also be possible to use the concept for mixtures of more than three components, if the nature of the gas composition is known to some extent. PMID:14552356

  16. Design and Analysis of Underwater Acoustic Networks with Reflected Links

    NASA Astrophysics Data System (ADS)

    Emokpae, Lloyd

    Underwater acoustic networks (UWANs) have applications in environmental state monitoring, oceanic profile measurements, leak detection in oil fields, distributed surveillance, and navigation. For these applications, sets of nodes are employed to collaboratively monitor an area of interest and track certain events or phenomena. In addition, it is common to find autonomous underwater vehicles (AUVs) acting as mobile sensor nodes that perform search-and-rescue missions, reconnaissance in combat zones, and coastal patrol. These AUVs are to work cooperatively to achieve a desired goal and thus need to be able to, in an ad-hoc manner, establish and sustain communication links in order to ensure some desired level of quality of service. Therefore, each node is required to adapt to environmental changes and be able to overcome broken communication links caused by external noise affecting the communication channel due to node mobility. In addition, since radio waves are quickly absorbed in the water medium, it is common for most underwater applications to rely on acoustic (or sound) rather than radio channels for mid-to-long range communications. However, acoustic channels pose multiple challenging issues, most notably the high transmission delay due to slow signal propagation and the limited channel bandwidth due to high frequency attenuation. Moreover, the inhomogeneous property of the water medium affects the sound speed profile while the signal surface and bottom reflections leads to multipath effects. In this dissertation, we address these networking challenges by developing protocols that take into consideration the underwater physical layer dynamics. We begin by introducing a novel surface-based reflection scheme (SBR), which takes advantage of the multipath effects of the acoustic channel. SBR works by using reflections from the water surface, and bottom, to establish non-line-of-sight (NLOS) communication links. SBR makes it possible to incorporate both line

  17. High-frequency shear-horizontal surface acoustic wave sensor

    SciTech Connect

    Branch, Darren W

    2013-05-07

    A Love wave sensor uses a single-phase unidirectional interdigital transducer (IDT) on a piezoelectric substrate for leaky surface acoustic wave generation. The IDT design minimizes propagation losses, bulk wave interferences, provides a highly linear phase response, and eliminates the need for impedance matching. As an example, a high frequency (.about.300-400 MHz) surface acoustic wave (SAW) transducer enables efficient excitation of shear-horizontal waves on 36.degree. Y-cut lithium tantalate (LTO) giving a highly linear phase response (2.8.degree. P-P). The sensor has the ability to detect at the pg/mm.sup.2 level and can perform multi-analyte detection in real-time. The sensor can be used for rapid autonomous detection of pathogenic microorganisms and bioagents by field deployable platforms.

  18. High-frequency shear-horizontal surface acoustic wave sensor

    SciTech Connect

    Branch, Darren W

    2014-03-11

    A Love wave sensor uses a single-phase unidirectional interdigital transducer (IDT) on a piezoelectric substrate for leaky surface acoustic wave generation. The IDT design minimizes propagation losses, bulk wave interferences, provides a highly linear phase response, and eliminates the need for impedance matching. As an example, a high frequency (.about.300-400 MHz) surface acoustic wave (SAW) transducer enables efficient excitation of shear-horizontal waves on 36.degree. Y-cut lithium tantalate (LTO) giving a highly linear phase response (2.8.degree. P-P). The sensor has the ability to detect at the pg/mm.sup.2 level and can perform multi-analyte detection in real-time. The sensor can be used for rapid autonomous detection of pathogenic microorganisms and bioagents by field deployable platforms.

  19. Vehicle exhaust gas chemical sensors using acoustic wave resonators

    SciTech Connect

    Cernosek, R.W.; Small, J.H.; Sawyer, P.S.; Bigbie, J.R.; Anderson, M.T.

    1998-03-01

    Under Sandia`s Laboratory Directed Research and Development (LDRD) program, novel acoustic wave-based sensors were explored for detecting gaseous chemical species in vehicle exhaust streams. The need exists for on-line, real-time monitors to continuously analyze the toxic exhaust gases -- nitrogen oxides (NOx), carbon monoxide (CO), and hydrocarbons (HC) -- for determining catalytic converter efficiency, documenting compliance to emission regulations, and optimizing engine performance through feedback control. In this project, the authors adapted existing acoustic wave chemical sensor technology to the high temperature environment and investigated new robust sensor materials for improving gas detection sensitivity and selectivity. This report describes one new sensor that has potential use as an exhaust stream residual hydrocarbon monitor. The sensor consists of a thickness shear mode (TSM) quartz resonator coated with a thin mesoporous silica layer ion-exchanged with palladium ions. When operated at temperatures above 300 C, the high surface area film catalyzes the combustion of the hydrocarbon vapors in the presence of oxygen. The sensor acts as a calorimeter as the exothermic reaction slightly increases the temperature, stressing the sensor surface, and producing a measurable deviation in the resonator frequency. Sensitivities as high as 0.44 (ppm-{Delta}f) and (ppm-gas) have been measured for propylene gas, with minimum detectable signals of < 50 ppm of propylene at 500 C.

  20. Environmental Monitoring Using Sensor Networks

    NASA Astrophysics Data System (ADS)

    Yang, J.; Zhang, C.; Li, X.; Huang, Y.; Fu, S.; Acevedo, M. F.

    2008-12-01

    Environmental observatories, consisting of a variety of sensor systems, computational resources and informatics, are important for us to observe, model, predict, and ultimately help preserve the health of the nature. The commoditization and proliferation of coin-to-palm sized wireless sensors will allow environmental monitoring with unprecedented fine spatial and temporal resolution. Once scattered around, these sensors can identify themselves, locate their positions, describe their functions, and self-organize into a network. They communicate through wireless channel with nearby sensors and transmit data through multi-hop protocols to a gateway, which can forward information to a remote data server. In this project, we describe an environmental observatory called Texas Environmental Observatory (TEO) that incorporates a sensor network system with intertwined wired and wireless sensors. We are enhancing and expanding the existing wired weather stations to include wireless sensor networks (WSNs) and telemetry using solar-powered cellular modems. The new WSNs will monitor soil moisture and support long-term hydrologic modeling. Hydrologic models are helpful in predicting how changes in land cover translate into changes in the stream flow regime. These models require inputs that are difficult to measure over large areas, especially variables related to storm events, such as soil moisture antecedent conditions and rainfall amount and intensity. This will also contribute to improve rainfall estimations from meteorological radar data and enhance hydrological forecasts. Sensor data are transmitted from monitoring site to a Central Data Collection (CDC) Server. We incorporate a GPRS modem for wireless telemetry, a single-board computer (SBC) as Remote Field Gateway (RFG) Server, and a WSN for distributed soil moisture monitoring. The RFG provides effective control, management, and coordination of two independent sensor systems, i.e., a traditional datalogger-based wired

  1. Coded acoustic wave sensors and system using time diversity

    NASA Technical Reports Server (NTRS)

    Solie, Leland P. (Inventor); Hines, Jacqueline H. (Inventor)

    2012-01-01

    An apparatus and method for distinguishing between sensors that are to be wirelessly detected is provided. An interrogator device uses different, distinct time delays in the sensing signals when interrogating the sensors. The sensors are provided with different distinct pedestal delays. Sensors that have the same pedestal delay as the delay selected by the interrogator are detected by the interrogator whereas other sensors with different pedestal delays are not sensed. Multiple sensors with a given pedestal delay are provided with different codes so as to be distinguished from one another by the interrogator. The interrogator uses a signal that is transmitted to the sensor and returned by the sensor for combination and integration with the reference signal that has been processed by a function. The sensor may be a surface acoustic wave device having a differential impulse response with a power spectral density consisting of lobes. The power spectral density of the differential response is used to determine the value of the sensed parameter or parameters.

  2. Hybrid architecture for building secure sensor networks

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  3. Cloaking an acoustic sensor with single-negative materials

    SciTech Connect

    Cai, Chen; Zhu, Xue-Feng; Xu, Tao; Zou, Xin-Ye; Liang, Bin; Cheng, Jian-Chun

    2015-07-15

    In this review, a brief introduction is given to the development of acoustic superlens cloaks that allow the cloaked object to receive signals while its presence is not sensed by the surrounding, which can be regarded as “cloaking an acoustic sensor”. Remarkably, the designed cloak consists of single-negative materials with parameters independent of the background medium or the sensor system, which is proven to be a magnifying superlens. This has facilitated significantly the design and fabrication of acoustic cloaks that generally require double-negative materials with customized parameters. Such innovative design has then been simplified further as a multi-layered structure comprising of two alternately arranged complementary media with homogeneous isotropic single-negative materials. Based on this, a scattering analyses method is developed for the numerical simulation of such multi-layered cloak structures, which may serve as an efficient approach for the investigation on such devices.

  4. An invisible acoustic sensor based on parity-time symmetry.

    PubMed

    Fleury, Romain; Sounas, Dimitrios; Alù, Andrea

    2015-01-01

    Sensing an incoming signal is typically associated with absorbing a portion of its energy, inherently perturbing the measurement and creating reflections and shadows. Here, in contrast, we demonstrate a non-invasive, shadow-free, invisible sensor for airborne sound waves at audible frequencies, which fully absorbs the impinging signal, without at the same time perturbing its own measurement or creating a shadow. This unique sensing device is based on the unusual scattering properties of a parity-time (PT) symmetric metamaterial device formed by a pair of electro-acoustic resonators loaded with suitably tailored non-Foster electrical circuits, constituting the acoustic equivalent of a coherent perfect absorber coupled to a coherent laser. Beyond the specific application to non-invasive sensing, our work broadly demonstrates the unique relevance of PT-symmetric metamaterials for acoustics, loss compensation and extraordinary wave manipulation. PMID:25562746

  5. High-fidelity simulation capability for virtual testing of seismic and acoustic sensors

    NASA Astrophysics Data System (ADS)

    Wilson, D. Keith; Moran, Mark L.; Ketcham, Stephen A.; Lacombe, James; Anderson, Thomas S.; Symons, Neill P.; Aldridge, David F.; Marlin, David H.; Collier, Sandra L.; Ostashev, Vladimir E.

    2005-05-01

    This paper describes development and application of a high-fidelity, seismic/acoustic simulation capability for battlefield sensors. The purpose is to provide simulated sensor data so realistic that they cannot be distinguished by experts from actual field data. This emerging capability provides rapid, low-cost trade studies of unattended ground sensor network configurations, data processing and fusion strategies, and signatures emitted by prototype vehicles. There are three essential components to the modeling: (1) detailed mechanical signature models for vehicles and walkers, (2) high-resolution characterization of the subsurface and atmospheric environments, and (3) state-of-the-art seismic/acoustic models for propagating moving-vehicle signatures through realistic, complex environments. With regard to the first of these components, dynamic models of wheeled and tracked vehicles have been developed to generate ground force inputs to seismic propagation models. Vehicle models range from simple, 2D representations to highly detailed, 3D representations of entire linked-track suspension systems. Similarly detailed models of acoustic emissions from vehicle engines are under development. The propagation calculations for both the seismics and acoustics are based on finite-difference, time-domain (FDTD) methodologies capable of handling complex environmental features such as heterogeneous geologies, urban structures, surface vegetation, and dynamic atmospheric turbulence. Any number of dynamic sources and virtual sensors may be incorporated into the FDTD model. The computational demands of 3D FDTD simulation over tactical distances require massively parallel computers. Several example calculations of seismic/acoustic wave propagation through complex atmospheric and terrain environments are shown.

  6. High-Temperature Piezoelectric Crystals for Acoustic Wave Sensor Applications.

    PubMed

    Zu, Hongfei; Wu, Huiyan; Wang, Qing-Ming

    2016-03-01

    In this review paper, nine different types of high-temperature piezoelectric crystals and their sensor applications are overviewed. The important materials' properties of these piezoelectric crystals including dielectric constant, elastic coefficients, piezoelectric coefficients, electromechanical coupling coefficients, and mechanical quality factor are discussed in detail. The determination methods of these physical properties are also presented. Moreover, the growth methods, structures, and properties of these piezoelectric crystals are summarized and compared. Of particular interest are langasite and oxyborate crystals, which exhibit no phase transitions prior to their melting points ∼ 1500 °C and possess high electrical resistivity, piezoelectric coefficients, and mechanical quality factor at ultrahigh temperature ( ∼ 1000 °C). Finally, some research results on surface acoustic wave (SAW) and bulk acoustic wave (BAW) sensors developed using this high-temperature piezoelectric crystals are discussed.

  7. High-Temperature Piezoelectric Crystals for Acoustic Wave Sensor Applications.

    PubMed

    Zu, Hongfei; Wu, Huiyan; Wang, Qing-Ming

    2016-03-01

    In this review paper, nine different types of high-temperature piezoelectric crystals and their sensor applications are overviewed. The important materials' properties of these piezoelectric crystals including dielectric constant, elastic coefficients, piezoelectric coefficients, electromechanical coupling coefficients, and mechanical quality factor are discussed in detail. The determination methods of these physical properties are also presented. Moreover, the growth methods, structures, and properties of these piezoelectric crystals are summarized and compared. Of particular interest are langasite and oxyborate crystals, which exhibit no phase transitions prior to their melting points ∼ 1500 °C and possess high electrical resistivity, piezoelectric coefficients, and mechanical quality factor at ultrahigh temperature ( ∼ 1000 °C). Finally, some research results on surface acoustic wave (SAW) and bulk acoustic wave (BAW) sensors developed using this high-temperature piezoelectric crystals are discussed. PMID:26886982

  8. Dual mode acoustic wave sensor for precise pressure reading

    NASA Astrophysics Data System (ADS)

    Mu, Xiaojing; Kropelnicki, Piotr; Wang, Yong; Randles, Andrew Benson; Chuan Chai, Kevin Tshun; Cai, Hong; Gu, Yuan Dong

    2014-09-01

    In this letter, a Microelectromechanical system acoustic wave sensor, which has a dual mode (lateral field exited Lamb wave mode and surface acoustic wave (SAW) mode) behavior, is presented for precious pressure change read out. Comb-like interdigital structured electrodes on top of piezoelectric material aluminium nitride (AlN) are used to generate the wave modes. The sensor membrane consists of single crystalline silicon formed by backside-etching of the bulk material of a silicon on insulator wafer having variable device thickness layer (5 μm-50 μm). With this principle, a pressure sensor has been fabricated and mounted on a pressure test package with pressure applied to the backside of the membrane within a range of 0 psi to 300 psi. The temperature coefficient of frequency was experimentally measured in the temperature range of -50 °C to 300 °C. This idea demonstrates a piezoelectric based sensor having two modes SAW/Lamb wave for direct physical parameter—pressure readout and temperature cancellation which can operate in harsh environment such as oil and gas exploration, automobile and aeronautic applications using the dual mode behavior of the sensor and differential readout at the same time.

  9. Availability issues in wireless visual sensor networks.

    PubMed

    Costa, Daniel G; Silva, Ivanovitch; Guedes, Luiz Affonso; Vasques, Francisco; Portugal, Paulo

    2014-01-01

    Wireless visual sensor networks have been considered for a large set of monitoring applications related with surveillance, tracking and multipurpose visual monitoring. When sensors are deployed over a monitored field, permanent faults may happen during the network lifetime, reducing the monitoring quality or rendering parts or the entire network unavailable. In a different way from scalar sensor networks, camera-enabled sensors collect information following a directional sensing model, which changes the notions of vicinity and redundancy. Moreover, visual source nodes may have different relevancies for the applications, according to the monitoring requirements and cameras' poses. In this paper we discuss the most relevant availability issues related to wireless visual sensor networks, addressing availability evaluation and enhancement. Such discussions are valuable when designing, deploying and managing wireless visual sensor networks, bringing significant contributions to these networks. PMID:24526301

  10. Availability Issues in Wireless Visual Sensor Networks

    PubMed Central

    Costa, Daniel G.; Silva, Ivanovitch; Guedes, Luiz Affonso; Vasques, Francisco; Portugal, Paulo

    2014-01-01

    Wireless visual sensor networks have been considered for a large set of monitoring applications related with surveillance, tracking and multipurpose visual monitoring. When sensors are deployed over a monitored field, permanent faults may happen during the network lifetime, reducing the monitoring quality or rendering parts or the entire network unavailable. In a different way from scalar sensor networks, camera-enabled sensors collect information following a directional sensing model, which changes the notions of vicinity and redundancy. Moreover, visual source nodes may have different relevancies for the applications, according to the monitoring requirements and cameras' poses. In this paper we discuss the most relevant availability issues related to wireless visual sensor networks, addressing availability evaluation and enhancement. Such discussions are valuable when designing, deploying and managing wireless visual sensor networks, bringing significant contributions to these networks. PMID:24526301

  11. High-sensitivity acoustic sensors from nanofibre webs

    PubMed Central

    Lang, Chenhong; Fang, Jian; Shao, Hao; Ding, Xin; Lin, Tong

    2016-01-01

    Considerable interest has been devoted to converting mechanical energy into electricity using polymer nanofibres. In particular, piezoelectric nanofibres produced by electrospinning have shown remarkable mechanical energy-to-electricity conversion ability. However, there is little data for the acoustic-to-electric conversion of electrospun nanofibres. Here we show that electrospun piezoelectric nanofibre webs have a strong acoustic-to-electric conversion ability. Using poly(vinylidene fluoride) as a model polymer and a sensor device that transfers sound directly to the nanofibre layer, we show that the sensor devices can detect low-frequency sound with a sensitivity as high as 266 mV Pa−1. They can precisely distinguish sound waves in low to middle frequency region. These features make them especially suitable for noise detection. Our nanofibre device has more than five times higher sensitivity than a commercial piezoelectric poly(vinylidene fluoride) film device. Electrospun piezoelectric nanofibres may be useful for developing high-performance acoustic sensors. PMID:27005010

  12. Microstructured polymer optical fibre sensors for opto-acoustic endoscopy

    NASA Astrophysics Data System (ADS)

    Broadway, Christian; Gallego, Daniel; Pospori, Andreas; Zubel, Michal; Webb, David J.; Sugden, Kate; Carpintero, Guillermo; Lamela, Horacio

    2016-04-01

    Opto-acoustic imaging is a growing field of research in recent years, providing functional imaging of physiological biomarkers, such as the oxygenation of haemoglobin. Piezo electric transducers are the industry standard detector for ultrasonics, but their limited bandwidth, susceptibility to electromagnetic interference and their inversely proportional sensitivity to size all affect the detector performance. Sensors based on polymer optical fibres (POF) are immune to electromagnetic interference, have lower acoustic impedance and a reduced Young's Modulus compared to silica fibres. Furthermore, POF enables the possibility of a wideband sensor and a size appropriate to endoscopy. Micro-structured POF (mPOF) used in an interferometric detector has been shown to be an order of magnitude more sensitive than silica fibre at 1 MHz and 3 times more sensitive at 10 MHz. We present the first opto-acoustic measurements obtained using a 4.7mm PMMA mPOF Bragg grating with a fibre diameter of 130 μm and present the lateral directivity pattern of a PMMA mPOF FBG ultrasound sensor over a frequency range of 1-50 MHz. We discuss the impact of the pattern with respect to the targeted application and draw conclusions on how to mitigate the problems encountered.

  13. High-sensitivity acoustic sensors from nanofibre webs.

    PubMed

    Lang, Chenhong; Fang, Jian; Shao, Hao; Ding, Xin; Lin, Tong

    2016-01-01

    Considerable interest has been devoted to converting mechanical energy into electricity using polymer nanofibres. In particular, piezoelectric nanofibres produced by electrospinning have shown remarkable mechanical energy-to-electricity conversion ability. However, there is little data for the acoustic-to-electric conversion of electrospun nanofibres. Here we show that electrospun piezoelectric nanofibre webs have a strong acoustic-to-electric conversion ability. Using poly(vinylidene fluoride) as a model polymer and a sensor device that transfers sound directly to the nanofibre layer, we show that the sensor devices can detect low-frequency sound with a sensitivity as high as 266 mV Pa(-1). They can precisely distinguish sound waves in low to middle frequency region. These features make them especially suitable for noise detection. Our nanofibre device has more than five times higher sensitivity than a commercial piezoelectric poly(vinylidene fluoride) film device. Electrospun piezoelectric nanofibres may be useful for developing high-performance acoustic sensors. PMID:27005010

  14. Autonomic and Coevolutionary Sensor Networking

    NASA Astrophysics Data System (ADS)

    Boonma, Pruet; Suzuki, Junichi

    (WSNs) applications are often required to balance the tradeoffs among conflicting operational objectives (e.g., latency and power consumption) and operate at an optimal tradeoff. This chapter proposes and evaluates a architecture, called BiSNET/e, which allows WSN applications to overcome this issue. BiSNET/e is designed to support three major types of WSN applications: , and hybrid applications. Each application is implemented as a decentralized group of, which is analogous to a bee colony (application) consisting of bees (agents). Agents collect sensor data or detect an event (a significant change in sensor reading) on individual nodes, and carry sensor data to base stations. They perform these data collection and event detection functionalities by sensing their surrounding network conditions and adaptively invoking behaviors such as pheromone emission, reproduction, migration, swarming and death. Each agent has its own behavior policy, as a set of genes, which defines how to invoke its behaviors. BiSNET/e allows agents to evolve their behavior policies (genes) across generations and autonomously adapt their performance to given objectives. Simulation results demonstrate that, in all three types of applications, agents evolve to find optimal tradeoffs among conflicting objectives and adapt to dynamic network conditions such as traffic fluctuations and node failures/additions. Simulation results also illustrate that, in hybrid applications, data collection agents and event detection agents coevolve to augment their adaptability and performance.

  15. Intent-based resource deployment in wireless sensor networks

    NASA Astrophysics Data System (ADS)

    de Mel, Geeth; Pham, Tien; Sullivan, Paul; Grueneberg, Keith; Vasconcelos, Wamberto; Norman, Tim

    2012-06-01

    Information derived from sensor networks plays a crucial role in the success of many critical tasks such as surveillance, and border monitoring. In order to derive the correct information at the right time, sensor data must be captured at desired locations with respect to the operational tasks in concern. Therefore, it is important that at the planning stage of a mission, sensing resources are best placed in the field to capture the required data. For example, consider a mission goal identify snipers, in an operational area before troops are deployed - two acoustic arrays and a day-night video camera are needed to successfully achieve this goal. This is because, if the resources are placed in correct locations, two acoustic arrays could provide direction of the shooter and a possible location by triangulating acoustic data whereas the day-night camera could produce an affirmative image of the perpetrators. In order to deploy the sensing resources intelligently to support the user decisions, in this paper we propose a Semantic Web based knowledge layer to identify the required resources in a sensor network and deploy the needed resources through a sensor infrastructure. The knowledge layer captures crucial information such as resources configurations, their intended use (e.g., two acoustic arrays deployed in a particular formation with day-night camera are needed to identify perpetrators in a possible sniper attack). The underlying sensor infrastructure will assists the process by exposing the information about deployed resources, resources in theatre, and location information about tasks, resources and so on.

  16. Zinc oxide thin film acoustic sensor

    SciTech Connect

    Mohammed, Ali Jasim; Salih, Wafaa Mahdi; Hassan, Marwa Abdul Muhsien; Nusseif, Asmaa Deiaa; Kadhum, Haider Abdullah; Mansour, Hazim Louis

    2013-12-16

    This paper reports the implementation of (750 nm) thickness of Zinc Oxide (ZnO) thin film for the piezoelectric pressure sensors. The film was prepared and deposited employing the spray pyrolysis technique. XRD results show that the growth preferred orientation is the (002) plane. A polycrystalline thin film (close to mono crystallite like) was obtained. Depending on the Scanning Electron Microscopy photogram, the film homogeneity and thickness were shown. The resonance frequency measured (about 19 kHz) and the damping coefficient was calculated and its value was found to be about (2.5538), the thin film be haves as homogeneous for under and over damped. The thin film pressure sensing was approximately exponentially related with frequency, the thin film was observed to has a good response for mechanical stresses also it is a good material for the piezoelectric properties.

  17. Simulation of detection and beamforming with acoustical ground sensors

    NASA Astrophysics Data System (ADS)

    Wilson, D. Keith; Sadler, Brian M.; Pham, Tien

    2002-08-01

    An interactive platform has been developed for simulating the detection and direction-finding performance of battlefield acoustic ground sensors. The simulations use the Acoustic Battlefield Aid (ABFA) as a computational engine to determine the signal propagation and resulting frequency-domain signal characteristics at the receiving sensor array. There are three components to the propagation predictions: the transmission loss (signal attenuation from target to sensor), signal saturation (degree of signal randomization), and signal coherence across the beamforming array. The transmission loss is predicted with a parabolic solution to the wave equation that accounts for sound refraction and ground interactions; signal saturation and coherence are predicted from the theory for line-of-sight wave propagation through turbulence. Based on these calculations, random frequency-domain signal samples are generated. The signal samples are then mixed with noise and fed to the selected detection or beamforming algorithm. After averaging over a number of trials, results are overlaid on a terrain map to show the sensor coverage. Currently available algorithms include the Neyman-Pearson criterion and Bayes risk minimization for detection, and the conventional, MVDR, and MUSIC beamformers. Users can readily add their own algorithms through a 'plug-in' interface. The interface requires only a text file listing the algorithm parameters and defaults, and a Matlab routine or Windows dynamic link library that implements the algorithm.

  18. A micromachined surface acoustic wave sensor for detecting inert gases

    SciTech Connect

    Ahuja, S.; Hersam, M.; Ross, C.; Chien, H.T.; Raptis, A.C.

    1996-12-31

    Surface acoustic wave (SAW) sensors must be specifically designed for each application because many variables directly affect the acoustic wave velocity. In the present work, the authors have designed, fabricated, and tested an SAW sensor for detection of metastable states of He. The sensor consists of two sets of micromachined interdigitated transducers (IDTs) and delay lines fabricated by photolithography on a single Y-cut LiNbO{sub 3} substrate oriented for Z-propagation of the SAWs. One set is used as a reference and the other set employs a delay line coated with a titanium-based thin film sensitive to electrical conductivity changes when exposed to metastable states of He. The reference sensor is used to obtain a true frequency translation in relation to a voltage controlled oscillator. An operating frequency of 109 MHz has been used, and the IDT finger width is 8 {micro}m. Variation in electrical conductivity of the thin film at the delay line due to exposure to He is detected as a frequency shift in the assembly, which is then used as a measure of the amount of metastable He exposed to the sensing film on the SAW delay line. A variation in the He pressure versus frequency shifts indicates the extent of the metastable He interaction.

  19. Robotic vehicle uses acoustic sensors for voice detection and diagnostics

    NASA Astrophysics Data System (ADS)

    Young, Stuart H.; Scanlon, Michael V.

    2000-07-01

    An acoustic sensor array that cues an imaging system on a small tele- operated robotic vehicle was used to detect human voice and activity inside a building. The advantage of acoustic sensors is that it is a non-line of sight (NLOS) sensing technology that can augment traditional LOS sensors such as visible and IR cameras. Acoustic energy emitted from a target, such as from a person, weapon, or radio, will travel through walls and smoke, around corners, and down corridors, whereas these obstructions would cripple an imaging detection system. The hardware developed and tested used an array of eight microphones to detect the loudest direction and automatically setter a camera's pan/tilt toward the noise centroid. This type of system has applicability for counter sniper applications, building clearing, and search/rescue. Data presented will be time-frequency representations showing voice detected within rooms and down hallways at various ranges. Another benefit of acoustics is that it provides the tele-operator some situational awareness clues via low-bandwidth transmission of raw audio data for the operator to interpret with either headphones or through time-frequency analysis. This data can be useful to recognize familiar sounds that might indicate the presence of personnel, such as talking, equipment, movement noise, etc. The same array also detects the sounds of the robot it is mounted on, and can be useful for engine diagnostics and trouble shooting, or for self-noise emanations for stealthy travel. Data presented will characterize vehicle self noise over various surfaces such as tiles, carpets, pavement, sidewalk, and grass. Vehicle diagnostic sounds will indicate a slipping clutch and repeated unexpected application of emergency braking mechanism.

  20. Collaborative Clustering for Sensor Networks

    NASA Technical Reports Server (NTRS)

    Wagstaff. Loro :/; Green Jillian; Lane, Terran

    2011-01-01

    Traditionally, nodes in a sensor network simply collect data and then pass it on to a centralized node that archives, distributes, and possibly analyzes the data. However, analysis at the individual nodes could enable faster detection of anomalies or other interesting events, as well as faster responses such as sending out alerts or increasing the data collection rate. There is an additional opportunity for increased performance if individual nodes can communicate directly with their neighbors. Previously, a method was developed by which machine learning classification algorithms could collaborate to achieve high performance autonomously (without requiring human intervention). This method worked for supervised learning algorithms, in which labeled data is used to train models. The learners collaborated by exchanging labels describing the data. The new advance enables clustering algorithms, which do not use labeled data, to also collaborate. This is achieved by defining a new language for collaboration that uses pair-wise constraints to encode useful information for other learners. These constraints specify that two items must, or cannot, be placed into the same cluster. Previous work has shown that clustering with these constraints (in isolation) already improves performance. In the problem formulation, each learner resides at a different node in the sensor network and makes observations (collects data) independently of the other learners. Each learner clusters its data and then selects a pair of items about which it is uncertain and uses them to query its neighbors. The resulting feedback (a must and cannot constraint from each neighbor) is combined by the learner into a consensus constraint, and it then reclusters its data while incorporating the new constraint. A strategy was also proposed for cleaning the resulting constraint sets, which may contain conflicting constraints; this improves performance significantly. This approach has been applied to collaborative

  1. Surface Acoustic Wave Vibration Sensors for Measuring Aircraft Flutter

    NASA Technical Reports Server (NTRS)

    Wilson, William C.; Moore, Jason P.; Juarez, Peter D.

    2016-01-01

    Under NASA's Advanced Air Vehicles Program the Advanced Air Transport Technology (AATT) Project is investigating flutter effects on aeroelastic wings. To support that work a new method for measuring vibrations due to flutter has been developed. The method employs low power Surface Acoustic Wave (SAW) sensors. To demonstrate the ability of the SAW sensor to detect flutter vibrations the sensors were attached to a Carbon fiber-reinforced polymer (CFRP) composite panel which was vibrated at six frequencies from 1Hz to 50Hz. The SAW data was compared to accelerometer data and was found to resemble sine waves and match each other closely. The SAW module design and results from the tests are presented here.

  2. Real-time GMAW quality classification using an artificial neural network with airborne acoustic signals as inputs

    SciTech Connect

    Matteson, A.; Morris, R.; Tate, R.

    1993-12-31

    The acoustic signal produced by the gas metal arc welding (GMAW) arc contains information about the behavior of the arc column, the molten pool and droplet transfer. It is possible to detect some defect producing conditions from the acoustic signal from the GMAW arc. An intelligent sensor, called the Weld Acoustic Monitor (WAM) has been developed to take advantage of this acoustic information in order to provide real-time quality assessment information for process control. The WAM makes use of an Artificial Neural Network (ANN) to classify the characteristic arc acoustic signals of acceptable and unacceptable welds. The ANN used in the Weld Acoustic Monitor developed its own set of rules for this classification problem by learning a data base of known GMAW acoustic signals.

  3. Mechanisms for Prolonging Network Lifetime in Wireless Sensor Networks

    ERIC Educational Resources Information Center

    Yang, Yinying

    2010-01-01

    Sensors are used to monitor and control the physical environment. A Wireless Sensor Network (WSN) is composed of a large number of sensor nodes that are densely deployed either inside the phenomenon or very close to it [18][5]. Sensor nodes measure various parameters of the environment and transmit data collected to one or more sinks, using…

  4. Following butter flavour deterioration with an acoustic wave sensor.

    PubMed

    Gaspar, Cláudia R B S; Gomes, M Teresa S R

    2012-09-15

    Off-flavours develop naturally in butter and the process is accelerated by heat. An acoustic wave sensor was used to detect the aroma compounds evolved from heated butter and the results have shown that registered marked changes were coincident to odour changes detected by sensory analysis. The flavour compounds have also been analysed by GC/MS for identification. The response of the sensor was fully characterized in terms of the sensitivity to each of the identified compounds, and sensitivities of the system SPME/sensor were compared with the sensitivities of the system SPME/GC/MS. It was found that the sensor analytical system was more sensitive to methylketones than to fatty acids. The SPME/GC/MS system also showed the highest sensitivity to 2-heptanone, followed by 2-nonanone, but third place was occupied by undecanone and butanoic acid, to which the sensor showed moderate sensitivity. 2-heptanone was found to be an appropriate model compound to follow odour changes till the 500 h, and the lower sensitivity of the sensor to butanoic acid showed to be a positive characteristic, as saturation was prevented, and other more subtle changes in the flavour could be perceived.

  5. Modelling the Energy Efficient Sensor Nodes for Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Dahiya, R.; Arora, A. K.; Singh, V. R.

    2015-09-01

    Energy is an important requirement of wireless sensor networks for better performance. A widely employed energy-saving technique is to place nodes in sleep mode, corresponding to low-power consumption as well as to reduce operational capabilities. In this paper, Markov model of a sensor network is developed. The node is considered to enter a sleep mode. This model is used to investigate the system performance in terms of energy consumption, network capacity and data delivery delay.

  6. Soldier detection using unattended acoustic and seismic sensors

    NASA Astrophysics Data System (ADS)

    Naz, P.; Hengy, S.; Hamery, P.

    2012-06-01

    During recent military conflicts, as well as for security interventions, the urban zone has taken a preponderant place. Studies have been initiated in national and in international programs to stimulate the technical innovations for these specific scenarios. For example joint field experiments have been organized by the NATO group SET-142 to evaluate the capability for the detection and localization of snipers, mortars or artillery guns using acoustic devices. Another important operational need corresponds to the protection of military sites or buildings. In this context, unattended acoustic and seismic sensors are envisaged to contribute to the survey of specific points by the detection of approaching enemy soldiers. This paper describes some measurements done in an anechoic chamber and in free field to characterize typical sounds generated by the soldier activities (walking, crawling, weapon handling, radio communication, clothing noises...). Footstep, speech and some specific impulsive sounds are detectable at various distances from the source. Such detection algorithms may be easily merged with the existing weapon firing detection algorithms to provide a more generic "battlefield acoustic" early warning system. Results obtained in various conditions (grassy terrain, gravel path, road, forest) will be presented. A method to extrapolate the distances of detection has been developed, based on an acoustic propagation model and applied to the laboratory measurements.

  7. Langasite Surface Acoustic Wave Sensors: Fabrication and Testing

    SciTech Connect

    Zheng, Peng; Greve, David W.; Oppenheim, Irving J.; Chin, Tao-Lun; Malone, Vanessa

    2012-02-01

    We report on the development of harsh-environment surface acoustic wave sensors for wired and wireless operation. Surface acoustic wave devices with an interdigitated transducer emitter and multiple reflectors were fabricated on langasite substrates. Both wired and wireless temperature sensing was demonstrated using radar-mode (pulse) detection. Temperature resolution of better than ±0.5°C was achieved between 200°C and 600°C. Oxygen sensing was achieved by depositing a layer of ZnO on the propagation path. Although the ZnO layer caused additional attenuation of the surface wave, oxygen sensing was accomplished at temperatures up to 700°C. The results indicate that langasite SAW devices are a potential solution for harsh-environment gas and temperature sensing.

  8. Single-sensor multispeaker listening with acoustic metamaterials.

    PubMed

    Xie, Yangbo; Tsai, Tsung-Han; Konneker, Adam; Popa, Bogdan-Ioan; Brady, David J; Cummer, Steven A

    2015-08-25

    Designing a "cocktail party listener" that functionally mimics the selective perception of a human auditory system has been pursued over the past decades. By exploiting acoustic metamaterials and compressive sensing, we present here a single-sensor listening device that separates simultaneous overlapping sounds from different sources. The device with a compact array of resonant metamaterials is demonstrated to distinguish three overlapping and independent sources with 96.67% correct audio recognition. Segregation of the audio signals is achieved using physical layer encoding without relying on source characteristics. This hardware approach to multichannel source separation can be applied to robust speech recognition and hearing aids and may be extended to other acoustic imaging and sensing applications.

  9. Single-sensor multispeaker listening with acoustic metamaterials.

    PubMed

    Xie, Yangbo; Tsai, Tsung-Han; Konneker, Adam; Popa, Bogdan-Ioan; Brady, David J; Cummer, Steven A

    2015-08-25

    Designing a "cocktail party listener" that functionally mimics the selective perception of a human auditory system has been pursued over the past decades. By exploiting acoustic metamaterials and compressive sensing, we present here a single-sensor listening device that separates simultaneous overlapping sounds from different sources. The device with a compact array of resonant metamaterials is demonstrated to distinguish three overlapping and independent sources with 96.67% correct audio recognition. Segregation of the audio signals is achieved using physical layer encoding without relying on source characteristics. This hardware approach to multichannel source separation can be applied to robust speech recognition and hearing aids and may be extended to other acoustic imaging and sensing applications. PMID:26261314

  10. Physically based simulation model for acoustic sensor robot navigation.

    PubMed

    Kuc, R; Siegel, M W

    1987-06-01

    A computer model is described that combines concepts from the fields of acoustics, linear system theory, and digital signal processing to simulate an acoustic sensor navigation system using time-of-flight ranging. By separating the transmitter/receiver into separate components and assuming mirror-like reflectors, closed-form solutions for the reflections from corners, edges, and walls are determined as a function of transducer size, location, and orientation. A floor plan consisting of corners, walls, and edges is efficiently encoded to indicate which of these elements contribute to a particular pulse-echo response. Sonar maps produced by transducers having different resonant frequencies and transmitted pulse waveforms can then be simulated efficiently. Examples of simulated sonar maps of two floor plans illustrate the performance of the model. Actual sonar maps are presented to verify the simulation results.

  11. Single-sensor multispeaker listening with acoustic metamaterials

    PubMed Central

    Xie, Yangbo; Tsai, Tsung-Han; Konneker, Adam; Popa, Bogdan-Ioan; Brady, David J.; Cummer, Steven A.

    2015-01-01

    Designing a “cocktail party listener” that functionally mimics the selective perception of a human auditory system has been pursued over the past decades. By exploiting acoustic metamaterials and compressive sensing, we present here a single-sensor listening device that separates simultaneous overlapping sounds from different sources. The device with a compact array of resonant metamaterials is demonstrated to distinguish three overlapping and independent sources with 96.67% correct audio recognition. Segregation of the audio signals is achieved using physical layer encoding without relying on source characteristics. This hardware approach to multichannel source separation can be applied to robust speech recognition and hearing aids and may be extended to other acoustic imaging and sensing applications. PMID:26261314

  12. Unique gel-coupled acoustic sensor array monitors human voice and physiology

    NASA Astrophysics Data System (ADS)

    Scanlon, Michael

    2002-11-01

    The health and performance of soldiers, firefighters, and other first responders in strenuous and hazardous environments can be continuously and remotely monitored with body-worn acoustic sensors. The Army Research Laboratory's gel-coupled acoustic physiological monitoring sensor has acoustic impedance properties similar to the skin that facilitate the transmission of body sounds into the sensor pad, yet significantly repel ambient airborne noises due to an impedance mismatch. Acoustic signal processing detects physiological events such as heartbeats, breaths, wheezes, coughs, blood pressure, activity, motion, and voice for communication and automatic speech recognition. Acoustic sensors can be in a helmet or in a strap around the neck, chest, and wrist. Although the physiological sounds have high SNR, the acoustic sensor also responds to motion-induced artifacts that sometimes obscure meaningful physiology. A noise-canceling sensor array configuration helps remove motion noise by using two acoustic sensors on the front sides of the neck and 2 additional acoustic sensors on each wrist. The motion noise detected on all 4 sensors will be dissimilar and out of phase, yet the physiology on all 4 sensors is covariant. Pulse wave transit time between neck and wrist will indicate systolic blood pressure. Data from a firefighter experiment will be presented.

  13. Simultaneous multipoint acoustic emission sensing using fibre acoustic wave grating sensors with identical spectrum

    NASA Astrophysics Data System (ADS)

    Lee, Jung-Ryul; Lee, Seung-Seok; Yoon, Dong-Jin

    2008-08-01

    This paper introduces the development of a simultaneous multipoint acoustic emission (AE) sensing system using a narrowband tuneable laser with high power and fibre acoustic wave grating sensors (FAWGSs). The demodulation technique is the same as that used in existing methods where the narrowband laser peak is tuned to one mid-reflection point in the main lobe of a fibre Bragg grating (FBG) spectrum. However, the sensor head is changed to an FAWGS for which a FBG is installed in a strain-free configuration so that it can detect AE waves in a structure not directly but in the form of a fibre-guided acoustic wave. Therefore since the structural strain cannot make the Bragg wavelength change, multiple FBGs with identical spectrum can be connected with multiple optical paths realized by equal light intensity dividers. The possible temperature difference between the multiple FAWGSs is passively resolved by using short FBGs which provide a wider operating temperature region. Consequently, we can resolve the problem that the FBG spectrum is easily deviated from the lasing wavelength because of the strain. In addition, the simultaneous multipoint sensing capability based on a single laser improves the cost-performance ratio of the optical system as well as reducing the structural inspection time, and enabling in situ health monitoring of real structures exposed to large and dynamic strains. The feasibility of the system is demonstrated in typical applications of in situ structural health monitoring based on AE techniques.

  14. The origin, history and future of fiber-optic interferometric acoustic sensors for US Navy applications

    NASA Astrophysics Data System (ADS)

    Cole, James H.; Bucaro, Joseph A.; Kirkendall, Clay K.; Dandridge, Anthony

    2011-05-01

    Fiber-optic interferometric acoustic sensors were first proposed for US Navy applications 36 years ago. This paper will review the origin, development and deployment of these sensors. Future applications will also be discussed.

  15. Using acoustic sensors to discriminate between nasal and mouth breathing.

    PubMed

    Curran, Kevin; Yuan, Peng; Coyle, Damian

    2012-01-01

    The recommendation to change breathing patterns from the mouth to the nose can have a significantly positive impact upon the general well being of the individual. We classify nasal and mouth breathing by using an acoustic sensor and intelligent signal processing techniques. The overall purpose is to investigate the possibility of identifying the differences in patterns between nasal and mouth breathing in order to integrate this information into a decision support system which will form the basis of a patient monitoring and motivational feedback system to recommend the change from mouth to nasal breathing.

  16. An acoustic vibration sensor based on tapered triple cladding fiber

    NASA Astrophysics Data System (ADS)

    Xu, Hui; Pang, Fufei; Zhao, Shiqi; Chen, Zhenyi; Wang, Tingyun

    2014-05-01

    An acoustic vibration sensor is investigated and demonstrated by using a tapered triple cladding fiber (TCF). It is fabricated by tapering a length of 2 cm TCF which is spliced between two single mode fibers (SMF). The TCF consists of core, inner cladding, middle cladding and outer cladding. After the tapering process, this structure becomes a tapered coaxial fiber coupler which presents a periodic filtering transmission spectrum. The surrounding vibration perturbation can be directly demodulated by intensity detection of the transmission power at a particular wavelength. The experimental result shows that the maximum frequency response of 700 kHz is achieved.

  17. Acoustic Sensors for Fission Gas Characterization in MTR Harsh Environment

    NASA Astrophysics Data System (ADS)

    Very, F.; Rosenkrantz, E.; Fourmentel, D.; Destouches, C.; Villard, J. F.; Combette, P.; Ferrandis, J. Y.

    Our group is now working for more than 15 years, in a close partnership with CEA, on the development of acoustic sensors devoted to the characterization of fission gas release for in-pile experiments in Material Testing Reactor. First of all, we will present the main principle of the method and the result of a first succeed experiment called REMORA 3 used to differentiate helium and fission gas released kinetics under transient operating condition [1]. Then we will present our new researches involving thick film transducers produced by screen-printing process in order to propose piezoelectric structures for harsh temperature and irradiation measurements in new MTR reactor.

  18. Networked sensors for the combat forces

    NASA Astrophysics Data System (ADS)

    Klager, Gene

    2004-11-01

    Real-time and detailed information is critical to the success of ground combat forces. Current manned reconnaissance, surveillance, and target acquisition (RSTA) capabilities are not sufficient to cover battlefield intelligence gaps, provide Beyond-Line-of-Sight (BLOS) targeting, and the ambush avoidance information necessary for combat forces operating in hostile situations, complex terrain, and conducting military operations in urban terrain. This paper describes a current US Army program developing advanced networked unmanned/unattended sensor systems to survey these gaps and provide the Commander with real-time, pertinent information. Networked Sensors for the Combat Forces plans to develop and demonstrate a new generation of low cost distributed unmanned sensor systems organic to the RSTA Element. Networked unmanned sensors will provide remote monitoring of gaps, will increase a unit"s area of coverage, and will provide the commander organic assets to complete his Battlefield Situational Awareness (BSA) picture for direct and indirect fire weapons, early warning, and threat avoidance. Current efforts include developing sensor packages for unmanned ground vehicles, small unmanned aerial vehicles, and unattended ground sensors using advanced sensor technologies. These sensors will be integrated with robust networked communications and Battle Command tools for mission planning, intelligence "reachback", and sensor data management. The network architecture design is based on a model that identifies a three-part modular design: 1) standardized sensor message protocols, 2) Sensor Data Management, and 3) Service Oriented Architecture. This simple model provides maximum flexibility for data exchange, information management and distribution. Products include: Sensor suites optimized for unmanned platforms, stationary and mobile versions of the Sensor Data Management Center, Battle Command planning tools, networked communications, and sensor management software. Details

  19. On computer vision in wireless sensor networks.

    SciTech Connect

    Berry, Nina M.; Ko, Teresa H.

    2004-09-01

    Wireless sensor networks allow detailed sensing of otherwise unknown and inaccessible environments. While it would be beneficial to include cameras in a wireless sensor network because images are so rich in information, the power cost of transmitting an image across the wireless network can dramatically shorten the lifespan of the sensor nodes. This paper describe a new paradigm for the incorporation of imaging into wireless networks. Rather than focusing on transmitting images across the network, we show how an image can be processed locally for key features using simple detectors. Contrasted with traditional event detection systems that trigger an image capture, this enables a new class of sensors which uses a low power imaging sensor to detect a variety of visual cues. Sharing these features among relevant nodes cues specific actions to better provide information about the environment. We report on various existing techniques developed for traditional computer vision research which can aid in this work.

  20. Energy optimization in mobile sensor networks

    NASA Astrophysics Data System (ADS)

    Yu, Shengwei

    Mobile sensor networks are considered to consist of a network of mobile robots, each of which has computation, communication and sensing capabilities. Energy efficiency is a critical issue in mobile sensor networks, especially when mobility (i.e., locomotion control), routing (i.e., communications) and sensing are unique characteristics of mobile robots for energy optimization. This thesis focuses on the problem of energy optimization of mobile robotic sensor networks, and the research results can be extended to energy optimization of a network of mobile robots that monitors the environment, or a team of mobile robots that transports materials from stations to stations in a manufacturing environment. On the energy optimization of mobile robotic sensor networks, our research focuses on the investigation and development of distributed optimization algorithms to exploit the mobility of robotic sensor nodes for network lifetime maximization. In particular, the thesis studies these five problems: 1. Network-lifetime maximization by controlling positions of networked mobile sensor robots based on local information with distributed optimization algorithms; 2. Lifetime maximization of mobile sensor networks with energy harvesting modules; 3. Lifetime maximization using joint design of mobility and routing; 4. Optimal control for network energy minimization; 5. Network lifetime maximization in mobile visual sensor networks. In addressing the first problem, we consider only the mobility strategies of the robotic relay nodes in a mobile sensor network in order to maximize its network lifetime. By using variable substitutions, the original problem is converted into a convex problem, and a variant of the sub-gradient method for saddle-point computation is developed for solving this problem. An optimal solution is obtained by the method. Computer simulations show that mobility of robotic sensors can significantly prolong the lifetime of the whole robotic sensor network while

  1. Fracture of human femur tissue monitored by acoustic emission sensors.

    PubMed

    Aggelis, Dimitrios G; Strantza, Maria; Louis, Olivia; Boulpaep, Frans; Polyzos, Demosthenes; van Hemelrijck, Danny

    2015-01-01

    The study describes the acoustic emission (AE) activity during human femur tissue fracture. The specimens were fractured in a bending-torsion loading pattern with concurrent monitoring by two AE sensors. The number of recorded signals correlates well with the applied load providing the onset of micro-fracture at approximately one sixth of the maximum load. Furthermore, waveform frequency content and rise time are related to the different modes of fracture (bending of femur neck or torsion of diaphysis). The importance of the study lies mainly in two disciplines. One is that, although femurs are typically subjects of surgical repair in humans, detailed monitoring of the fracture with AE will enrich the understanding of the process in ways that cannot be achieved using only the mechanical data. Additionally, from the point of view of monitoring techniques, applying sensors used for engineering materials and interpreting the obtained data pose additional difficulties due to the uniqueness of the bone structure.

  2. Fracture of Human Femur Tissue Monitored by Acoustic Emission Sensors

    PubMed Central

    Aggelis, Dimitrios. G.; Strantza, Maria; Louis, Olivia; Boulpaep, Frans; Polyzos, Demosthenes; van Hemelrijck, Danny

    2015-01-01

    The study describes the acoustic emission (AE) activity during human femur tissue fracture. The specimens were fractured in a bending-torsion loading pattern with concurrent monitoring by two AE sensors. The number of recorded signals correlates well with the applied load providing the onset of micro-fracture at approximately one sixth of the maximum load. Furthermore, waveform frequency content and rise time are related to the different modes of fracture (bending of femur neck or torsion of diaphysis). The importance of the study lies mainly in two disciplines. One is that, although femurs are typically subjects of surgical repair in humans, detailed monitoring of the fracture with AE will enrich the understanding of the process in ways that cannot be achieved using only the mechanical data. Additionally, from the point of view of monitoring techniques, applying sensors used for engineering materials and interpreting the obtained data pose additional difficulties due to the uniqueness of the bone structure. PMID:25763648

  3. Fracture of human femur tissue monitored by acoustic emission sensors.

    PubMed

    Aggelis, Dimitrios G; Strantza, Maria; Louis, Olivia; Boulpaep, Frans; Polyzos, Demosthenes; van Hemelrijck, Danny

    2015-01-01

    The study describes the acoustic emission (AE) activity during human femur tissue fracture. The specimens were fractured in a bending-torsion loading pattern with concurrent monitoring by two AE sensors. The number of recorded signals correlates well with the applied load providing the onset of micro-fracture at approximately one sixth of the maximum load. Furthermore, waveform frequency content and rise time are related to the different modes of fracture (bending of femur neck or torsion of diaphysis). The importance of the study lies mainly in two disciplines. One is that, although femurs are typically subjects of surgical repair in humans, detailed monitoring of the fracture with AE will enrich the understanding of the process in ways that cannot be achieved using only the mechanical data. Additionally, from the point of view of monitoring techniques, applying sensors used for engineering materials and interpreting the obtained data pose additional difficulties due to the uniqueness of the bone structure. PMID:25763648

  4. Querying and tasking in sensor networks

    NASA Astrophysics Data System (ADS)

    Jaikaeo, Chaiporn; Srisathapornphat, Chavalit; Shen, Chien-Chung

    2000-08-01

    With the advancement of hardware technology, it becomes feasible to develop a networked system of pervasive computing platforms that combine programmable general purpose computers with multiple sensing and wireless communication capability. This networked system of programmable sensor nodes, together called a sensor network, poses unique challenges on how information collected by and stored within the sensor network should be queried and accessed, and how concurrent sensing tasks should be programmed from external clients. In this paper, we describe an architecture that facilitates querying and tasking of sensor networks. The key idea to the architecture lies in the development of the Sensor Querying and Tasking Language (SQTL) and the corresponding Sensor Execution Environment (SEE). We model a sensor network as a distributed set of collaborating nodes that carry out querying and tasking activities programmed in SQTL. A frontend node injects a message, that encapsulates an SQTL program, into a sensor node and starts a diffusion computation. A sensor node may diffuse the encapsulated SQTL program to other nodes as dictated by its logic and collaborately perform the specified querying or tasking activity. We will present the SQTL language and demonstrate its applicability using a maximum temperature querying application and a vehicle tracking application.

  5. Time-domain fiber loop ringdown sensor and sensor network

    NASA Astrophysics Data System (ADS)

    Kaya, Malik

    Optical fibers have been mostly used in fiber optic communications, imaging optics, sensing technology, etc. Fiber optic sensors have gained increasing attention for scientific and structural health monitoring (SHM) applications. In this study, fiber loop ringdown (FLRD) sensors were fabricated for scientific, SHM, and sensor networking applications. FLRD biosensors were fabricated for both bulk refractive index (RI)- and surface RI-based DNA sensing and one type of bacteria sensing. Furthermore, the effect of glucose oxidase (GOD) immobilization at the sensor head on sensor performance was evaluated for both glucose and synthetic urine solutions with glucose concentration between 0.1% and 10%. Detection sensitivities of the glucose sensors were achieved as low as 0.05%. For chemical sensing, heavy water, ranging from 97% to 10%, and several elemental solutions were monitored by using the FLRD chemical sensors. Bulk index-based FLRD sensing showed that trace elements can be detected in deionized water. For physical sensing, water and cracking sensors were fabricated and embedded into concrete. A partially-etched single-mode fiber (SMF) was embedded into a concrete bar for water monitoring while a bare SMF without any treatment was directly embedded into another concrete bar for monitoring cracks. Furthermore, detection sensitivities of water and crack sensors were investigated as 10 ml water and 0.5 mm surface crack width, respectively. Additionally fiber loop ringdown-fiber Bragg grating temperature sensors were developed in the laboratory; two sensor units for water, crack, and temperature sensing were deployed into a concrete cube in a US Department of Energy test bed (Miami, FL). Multi-sensor applications in a real concrete structure were accomplished by testing the six FLRD sensors. As a final stage, a sensor network was assembled by multiplexing two or three FLRD sensors in series and parallel. Additionally, two FLRD sensors were combined in series and

  6. AUVs as integrated, adaptive acoustic sensors for ocean exploration

    NASA Astrophysics Data System (ADS)

    Schmidt, Henrik; Edwards, Joseph R.; Liu, Te-Chih; Montanari, Monica

    2001-05-01

    Autonomous underwater vehicles (AUV) are rapidly being transitioned into operational systems for national defense, offshore exploration, and ocean science. AUVs provide excellent sensor platform control, allowing for, e.g., accurate acoustic mapping of seabeds not easily reached by conventional platforms, such as the deep ocean. However, the full potential of the robotic platforms is far from exhausted by such applications. Thus, for example, most seabed-mapping applications use imaging sonar technology, the data volume of which cannot be transmitted back to the operators in real time due to the severe bandwidth limitation of the acoustic communication. The sampling patterns are therefore in general being preprogramed and the data are being stored for postmission analysis. This procedure is therefore associated with indiscriminate distribution of the sampling throughout the area of interest, irrespective of whether features of interest are present or not. However, today's computing technology allows for a significant amount of signal processing and analysis to be performed on the platforms, where the results may then be used for real-time adaptive sampling to optimally concentrate the sampling in area of interest, and compress the results to a few parameters which may be transmitted back to the operators. Such adaptive sensing concepts combining environmental acoustics, signal processing, and robotics are currently being developed for concurrent detection, localization, and classification of buried objects, with application to littoral mine countermeasures, deep ocean seabed characterization, and marine archeology. [Work supported by ONR and NATO Undersea Research Center.

  7. Communication and cooperation in underwater acoustic networks

    NASA Astrophysics Data System (ADS)

    Yerramalli, Srinivas

    In this thesis, we present a study of several problems related to underwater point to point communications and network formation. We explore techniques to improve the achievable data rate on a point to point link using better physical layer techniques and then study sensor cooperation which improves the throughput and reliability in an underwater network. Robust point-to-point communications in underwater networks has become increasingly critical in several military and civilian applications related to underwater communications. We present several physical layer signaling and detection techniques tailored to the underwater channel model to improve the reliability of data detection. First, a simplified underwater channel model in which the time scale distortion on each path is assumed to be the same (single scale channel model in contrast to a more general multi scale model). A novel technique, which exploits the nature of OFDM signaling and the time scale distortion, called Partial FFT Demodulation is derived. It is observed that this new technique has some unique interference suppression properties and performs better than traditional equalizers in several scenarios of interest. Next, we consider the multi scale model for the underwater channel and assume that single scale processing is performed at the receiver. We then derive optimized front end pre-processing techniques to reduce the interference caused during single scale processing of signals transmitted on a multi-scale channel. We then propose an improvised channel estimation technique using dictionary optimization methods for compressive sensing and show that significant performance gains can be obtained using this technique. In the next part of this thesis, we consider the problem of sensor node cooperation among rational nodes whose objective is to improve their individual data rates. We first consider the problem of transmitter cooperation in a multiple access channel and investigate the stability of

  8. Distributed estimation for adaptive sensor selection in wireless sensor networks

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  9. Networked sensors for the objective force

    NASA Astrophysics Data System (ADS)

    Howden, Ellen A.; Brendley, Keith

    2002-08-01

    The technical objectives of this effort are to develop low cost sensor packages optimized for three types of unmanned platforms: UGVs, SUAVs and UGS. Additional goals are to develop robust communications to network these sensor systems throughout complex terrain, develop command and control software tools to incldue mission planning, monitoring, dynamic re-planning, sensor planning and management functions; and to demonstrate a system-of-systems capability when fusing information from these various unmanned sensor systems. These capabilities provide the battlefield commander organic unmanned sensor network assets to compelte his Battlespace Situational Awareness picture for targeting, direct and indirect-fire weapons, and threat avoidance. The networked sensors will provide remote monitoring of areas of interest out to approximately 10km not covered by higher echelon surveillance assets and without placing soldiers in harm's way, will increase unit areas of coverage and will provide near real time BSA and targeting data for early warning to speed decision making and reaction time.

  10. Using Neural Networks for Sensor Validation

    NASA Technical Reports Server (NTRS)

    Mattern, Duane L.; Jaw, Link C.; Guo, Ten-Huei; Graham, Ronald; McCoy, William

    1998-01-01

    This paper presents the results of applying two different types of neural networks in two different approaches to the sensor validation problem. The first approach uses a functional approximation neural network as part of a nonlinear observer in a model-based approach to analytical redundancy. The second approach uses an auto-associative neural network to perform nonlinear principal component analysis on a set of redundant sensors to provide an estimate for a single failed sensor. The approaches are demonstrated using a nonlinear simulation of a turbofan engine. The fault detection and sensor estimation results are presented and the training of the auto-associative neural network to provide sensor estimates is discussed.

  11. Sensor Networks in the Low Lands

    PubMed Central

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

    2010-01-01

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

  12. Secured network sensor-based defense system

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  13. Minimum energy information fusion in sensor networks

    SciTech Connect

    Chapline, G

    1999-05-11

    In this paper we consider how to organize the sharing of information in a distributed network of sensors and data processors so as to provide explanations for sensor readings with minimal expenditure of energy. We point out that the Minimum Description Length principle provides an approach to information fusion that is more naturally suited to energy minimization than traditional Bayesian approaches. In addition we show that for networks consisting of a large number of identical sensors Kohonen self-organization provides an exact solution to the problem of combing the sensor outputs into minimal description length explanations.

  14. Securing radars using secure wireless sensor networking

    NASA Astrophysics Data System (ADS)

    Tahmoush, David

    2014-06-01

    Radar sensors can be viewed as a limited wireless sensor network consisting of radar transmitter nodes, target nodes, and radar receiver nodes. The radar transmitter node sends a communication signal to the target node which then reflects it in a known pattern to the radar receiver nodes. This type of wireless sensor network is susceptible to the same types of attacks as a traditional wireless sensor network, but there is less opportunity for defense. The target nodes in the network are unable to validate the return signal, and they are often uncooperative. This leads to ample opportunities for spoofing and man-in-the-middle attacks. This paper explores some of the fundamental techniques that can be used against a limited wireless network system as well as explores the techniques that can be used to counter them.

  15. Acoustic sensor planning for gunshot location in national parks: a pareto front approach.

    PubMed

    González-Castaño, Francisco Javier; Alonso, Javier Vales; Costa-Montenegro, Enrique; López-Matencio, Pablo; Vicente-Carrasco, Francisco; Parrado-García, Francisco J; Gil-Castiñeira, Felipe; Costas-Rodríguez, Sergio

    2009-01-01

    In this paper, we propose a solution for gunshot location in national parks. In Spain there are agencies such as SEPRONA that fight against poaching with considerable success. The DiANa project, which is endorsed by Cabaneros National Park and the SEPRONA service, proposes a system to automatically detect and locate gunshots. This work presents its technical aspects related to network design and planning. The system consists of a network of acoustic sensors that locate gunshots by hyperbolic multi-lateration estimation. The differences in sound time arrivals allow the computation of a low error estimator of gunshot location. The accuracy of this method depends on tight sensor clock synchronization, which an ad-hoc time synchronization protocol provides. On the other hand, since the areas under surveillance are wide, and electric power is scarce, it is necessary to maximize detection coverage and minimize system cost at the same time. Therefore, sensor network planning has two targets, i.e., coverage and cost. We model planning as an unconstrained problem with two objective functions. We determine a set of candidate solutions of interest by combining a derivative-free descent method we have recently proposed with a Pareto front approach. The results are clearly superior to random seeding in a realistic simulation scenario.

  16. Acoustic Sensor Planning for Gunshot Location in National Parks: A Pareto Front Approach

    PubMed Central

    González-Castaño, Francisco Javier; Alonso, Javier Vales; Costa-Montenegro, Enrique; López-Matencio, Pablo; Vicente-Carrasco, Francisco; Parrado-García, Francisco J.; Gil-Castiñeira, Felipe; Costas-Rodríguez, Sergio

    2009-01-01

    In this paper, we propose a solution for gunshot location in national parks. In Spain there are agencies such as SEPRONA that fight against poaching with considerable success. The DiANa project, which is endorsed by Cabaneros National Park and the SEPRONA service, proposes a system to automatically detect and locate gunshots. This work presents its technical aspects related to network design and planning. The system consists of a network of acoustic sensors that locate gunshots by hyperbolic multi-lateration estimation. The differences in sound time arrivals allow the computation of a low error estimator of gunshot location. The accuracy of this method depends on tight sensor clock synchronization, which an ad-hoc time synchronization protocol provides. On the other hand, since the areas under surveillance are wide, and electric power is scarce, it is necessary to maximize detection coverage and minimize system cost at the same time. Therefore, sensor network planning has two targets, i.e., coverage and cost. We model planning as an unconstrained problem with two objective functions. We determine a set of candidate solutions of interest by combining a derivative-free descent method we have recently proposed with a Pareto front approach. The results are clearly superior to random seeding in a realistic simulation scenario. PMID:22303135

  17. Energy-aware Scheduling of Surveillance in Wireless Multimedia Sensor Networks

    PubMed Central

    Wang, Xue; Wang, Sheng; Ma, Junjie; Sun, Xinyao

    2010-01-01

    Wireless sensor networks involve a large number of sensor nodes with limited energy supply, which impacts the behavior of their application. In wireless multimedia sensor networks, sensor nodes are equipped with audio and visual information collection modules. Multimedia contents are ubiquitously retrieved in surveillance applications. To solve the energy problems during target surveillance with wireless multimedia sensor networks, an energy-aware sensor scheduling method is proposed in this paper. Sensor nodes which acquire acoustic signals are deployed randomly in the sensing fields. Target localization is based on the signal energy feature provided by multiple sensor nodes, employing particle swarm optimization (PSO). During the target surveillance procedure, sensor nodes are adaptively grouped in a totally distributed manner. Specially, the target motion information is extracted by a forecasting algorithm, which is based on the hidden Markov model (HMM). The forecasting results are utilized to awaken sensor node in the vicinity of future target position. According to the two properties, signal energy feature and residual energy, the sensor nodes decide whether to participate in target detection separately with a fuzzy control approach. Meanwhile, the local routing scheme of data transmission towards the observer is discussed. Experimental results demonstrate the efficiency of energy-aware scheduling of surveillance in wireless multimedia sensor network, where significant energy saving is achieved by the sensor awakening approach and data transmission paths are calculated with low computational complexity. PMID:22319289

  18. Distributed acoustic fibre optic sensors for condition monitoring of pipelines

    NASA Astrophysics Data System (ADS)

    Hussels, Maria-Teresa; Chruscicki, Sebastian; Habib, Abdelkarim; Krebber, Katerina

    2016-05-01

    Industrial piping systems are particularly relevant to public safety and the continuous availability of infrastructure. However, condition monitoring systems based on many discrete sensors are generally not well-suited for widespread piping systems due to considerable installation effort, while use of distributed fibre-optic sensors would reduce this effort to a minimum. Specifically distributed acoustic sensing (DAS) is employed for detection of third-party threats and leaks in oil and gas pipelines in recent years and can in principle also be applied to industrial plants. Further possible detection routes amenable by DAS that could identify damage prior to emission of medium are subject of a current project at BAM, which aims at qualifying distributed fibre optic methods such as DAS as a means for spatially continuous monitoring of industrial piping systems. Here, first tests on a short pipe are presented, where optical fibres were applied directly to the surface. An artificial signal was used to define suitable parameters of the measurement system and compare different ways of applying the sensor.

  19. Optoelectronic hybrid fiber laser sensor for simultaneous acoustic and magnetic measurement.

    PubMed

    Wang, Zhaogang; Zhang, Wentao; Huang, Wenzhu; Feng, Shengwen; Li, Fang

    2015-09-21

    An optoelectronic hybrid fiber optic acoustic and magnetic sensor (FOAMS) based on fiber laser sensing is proposed, which can measure acoustic and magnetic field simultaneously. A static magnetic field signal can be carried by an AC Lorentz force, and demodulated in frequency domain together with acoustic signals. Some experiments of acoustic pressure sensitivity, magnetic field sensitivity, and simultaneous acoustic and magnetic measurement on a fabricated FOAMS were carried out. The acoustic pressure sensitivity was about -164.7 dB (0 dB re 1 pm/μPa) and the magnetic field sensitivity was 0.6 dB (0 dB re 1 pm/ (T•A)). The experiment of simultaneous acoustic and magnetic measurement shows that the detections of acoustic and magnetic field have little effect on each other in dynamic range and simultaneously measuring acoustic and magnetic field is feasible. PMID:26406643

  20. Networked sensors: armor for the future force

    NASA Astrophysics Data System (ADS)

    Gowens, John W., II; Eicke, John

    2001-08-01

    The U.S. Army has embarked on an important campaign to field a lighter, more agile force, capable of being deployed in a fraction of the time currently required. The survivability of this force will depend more heavily on the use of integrated command and control capabilities with unsurpassed situational understanding for all levels of command. Arrays of small, low cost sensors will play a key role in detecting, locating, tracking, and identifying targets, particularly in areas where the terrain or other circumstances prevent traditional high performance sensors from providing critical information. Individual sensor types will provide modest performance but with a wide range of sensing modalities. When deployed in large numbers, the data fused from multiple sensing modalities will provide a detailed view of the battlespace over a wide area. A critical element necessary to deploy unattended ground sensor technology is the underlying communications and networking infrastructure. Communication networks will constitute the major challenge to making unattended ground sensors networks practical.

  1. Impact sensor network for detection of hypervelocity impacts on spacecraft

    NASA Astrophysics Data System (ADS)

    Schäfer, Frank; Janovsky, Rolf

    2007-11-01

    With regard to hypervelocity impact detection, a sensor network that can be applied on typical spacecraft structures is under development at Fraunhofer EMI (Ernst-Mach-Institut), supported by OHB-System. For impact detection, acoustic transducers are used. The structure types investigated are a 2 mm thick plate from aluminium alloy and a 49 mm thick sandwich panel with aluminium face-sheets and aluminium honeycomb core. One impact test was performed on each of the panels, which were instrumented with 6 ultrasonic transducers. The signals recorded at the various sensor locations varied with regard to peak amplitude and elapse time of the signal. Using this information and combining it with a localization algorithm, the impact location could be successfully determined. A description of the impact sensor network and the mathematical model to determine the impact location is provided. The impact tests on the spacecraft structure, the response of the sensor network and the analysis performed to determine the impact location are described.

  2. Establishing trust in decentralized smart sensor networks

    NASA Astrophysics Data System (ADS)

    Vagts, H.; Cosar, T.; Beyerer, J.

    2011-06-01

    Smart sensors can gather all kind of information and process it. Cameras are still dominating and smart cameras can offer services for face recognition or person tracking. Operators are building collaborations to cover a larger area, to save costs and to add more and different sensors. Cryptographic methods may achieve integrity and confidentiality between operators, but not trust. Even if a partner or one of his sensors is authenticated, no statements can be made about the quality of the sensor data. Hence, trust must be established between the partners and their sensors. Trust can be built based on past experience. A reputation system collects opinions of operators about the behavior of sensors and calculates trust based on these opinions. Many reputation systems have been proposed, e.g., for authentication of files in peer-topeer networks. This work presents a new reputation system, which is designed to calculate the trustworthiness of smart sensors and smart sensor systems. A new trust model, including functions to calculate and update trust on past experiences, is proposed. When fusing information of multiple sensors, it cannot always be reconstructed, which information led to a bad result. Hence, an approach for fair rating is shown. The proposed system has been realized in a Service-Oriented Architecture for easy integration in existing smart sensor systems, e.g., smart surveillance systems. The model itself can be used in every decentralized heterogeneous smart sensor network.

  3. Reputation-based secure sensor localization in wireless sensor networks.

    PubMed

    He, Jingsha; Xu, Jing; Zhu, Xingye; Zhang, Yuqiang; Zhang, Ting; Fu, Wanqing

    2014-01-01

    Location information of sensor nodes in wireless sensor networks (WSNs) is very important, for it makes information that is collected and reported by the sensor nodes spatially meaningful for applications. Since most current sensor localization schemes rely on location information that is provided by beacon nodes for the regular sensor nodes to locate themselves, the accuracy of localization depends on the accuracy of location information from the beacon nodes. Therefore, the security and reliability of the beacon nodes become critical in the localization of regular sensor nodes. In this paper, we propose a reputation-based security scheme for sensor localization to improve the security and the accuracy of sensor localization in hostile or untrusted environments. In our proposed scheme, the reputation of each beacon node is evaluated based on a reputation evaluation model so that regular sensor nodes can get credible location information from highly reputable beacon nodes to accomplish localization. We also perform a set of simulation experiments to demonstrate the effectiveness of the proposed reputation-based security scheme. And our simulation results show that the proposed security scheme can enhance the security and, hence, improve the accuracy of sensor localization in hostile or untrusted environments.

  4. Reputation-Based Secure Sensor Localization in Wireless Sensor Networks

    PubMed Central

    He, Jingsha; Xu, Jing; Zhu, Xingye; Zhang, Yuqiang; Zhang, Ting; Fu, Wanqing

    2014-01-01

    Location information of sensor nodes in wireless sensor networks (WSNs) is very important, for it makes information that is collected and reported by the sensor nodes spatially meaningful for applications. Since most current sensor localization schemes rely on location information that is provided by beacon nodes for the regular sensor nodes to locate themselves, the accuracy of localization depends on the accuracy of location information from the beacon nodes. Therefore, the security and reliability of the beacon nodes become critical in the localization of regular sensor nodes. In this paper, we propose a reputation-based security scheme for sensor localization to improve the security and the accuracy of sensor localization in hostile or untrusted environments. In our proposed scheme, the reputation of each beacon node is evaluated based on a reputation evaluation model so that regular sensor nodes can get credible location information from highly reputable beacon nodes to accomplish localization. We also perform a set of simulation experiments to demonstrate the effectiveness of the proposed reputation-based security scheme. And our simulation results show that the proposed security scheme can enhance the security and, hence, improve the accuracy of sensor localization in hostile or untrusted environments. PMID:24982940

  5. Langasite Surface Acoustic Wave Gas Sensors: Modeling and Verification

    SciTech Connect

    Zheng, Peng; Greve, David W; Oppenheim, Irving J

    2013-01-01

    We report finite element simulations of the effect of conductive sensing layers on the surface wave velocity of langasite substrates. The simulations include both the mechanical and electrical influences of the conducting sensing layer. We show that three-dimensional simulations are necessary because of the out-of-plane displacements of the commonly used (0, 138.5, 26.7) Euler angle. Measurements of the transducer input admittance in reflective delay-line devices yield a value for the electromechanical coupling coefficient that is in good agreement with the three-dimensional simulations on bare langasite substrate. The input admittance measurements also show evidence of excitation of an additional wave mode and excess loss due to the finger resistance. The results of these simulations and measurements will be useful in the design of surface acoustic wave gas sensors.

  6. Wireless Sensor Array Network DoA Estimation from Compressed Array Data via Joint Sparse Representation.

    PubMed

    Yu, Kai; Yin, Ming; Luo, Ji-An; Wang, Yingguan; Bao, Ming; Hu, Yu-Hen; Wang, Zhi

    2016-05-23

    A compressive sensing joint sparse representation direction of arrival estimation (CSJSR-DoA) approach is proposed for wireless sensor array networks (WSAN). By exploiting the joint spatial and spectral correlations of acoustic sensor array data, the CSJSR-DoA approach provides reliable DoA estimation using randomly-sampled acoustic sensor data. Since random sampling is performed at remote sensor arrays, less data need to be transmitted over lossy wireless channels to the fusion center (FC), and the expensive source coding operation at sensor nodes can be avoided. To investigate the spatial sparsity, an upper bound of the coherence of incoming sensor signals is derived assuming a linear sensor array configuration. This bound provides a theoretical constraint on the angular separation of acoustic sources to ensure the spatial sparsity of the received acoustic sensor array signals. The Cram e ´ r-Rao bound of the CSJSR-DoA estimator that quantifies the theoretical DoA estimation performance is also derived. The potential performance of the CSJSR-DoA approach is validated using both simulations and field experiments on a prototype WSAN platform. Compared to existing compressive sensing-based DoA estimation methods, the CSJSR-DoA approach shows significant performance improvement.

  7. Wireless Sensor Array Network DoA Estimation from Compressed Array Data via Joint Sparse Representation

    PubMed Central

    Yu, Kai; Yin, Ming; Luo, Ji-An; Wang, Yingguan; Bao, Ming; Hu, Yu-Hen; Wang, Zhi

    2016-01-01

    A compressive sensing joint sparse representation direction of arrival estimation (CSJSR-DoA) approach is proposed for wireless sensor array networks (WSAN). By exploiting the joint spatial and spectral correlations of acoustic sensor array data, the CSJSR-DoA approach provides reliable DoA estimation using randomly-sampled acoustic sensor data. Since random sampling is performed at remote sensor arrays, less data need to be transmitted over lossy wireless channels to the fusion center (FC), and the expensive source coding operation at sensor nodes can be avoided. To investigate the spatial sparsity, an upper bound of the coherence of incoming sensor signals is derived assuming a linear sensor array configuration. This bound provides a theoretical constraint on the angular separation of acoustic sources to ensure the spatial sparsity of the received acoustic sensor array signals. The Crame´r–Rao bound of the CSJSR-DoA estimator that quantifies the theoretical DoA estimation performance is also derived. The potential performance of the CSJSR-DoA approach is validated using both simulations and field experiments on a prototype WSAN platform. Compared to existing compressive sensing-based DoA estimation methods, the CSJSR-DoA approach shows significant performance improvement. PMID:27223287

  8. Ultra-wideband radar sensors and networks

    DOEpatents

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

    2013-08-06

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

  9. A lightweight sensor network management system design

    USGS Publications Warehouse

    Yuan, F.; Song, W.-Z.; Peterson, N.; Peng, Y.; Wang, L.; Shirazi, B.; LaHusen, R.

    2008-01-01

    In this paper, we propose a lightweight and transparent management framework for TinyOS sensor networks, called L-SNMS, which minimizes the overhead of management functions, including memory usage overhead, network traffic overhead, and integration overhead. We accomplish this by making L-SNMS virtually transparent to other applications hence requiring minimal integration. The proposed L-SNMS framework has been successfully tested on various sensor node platforms, including TelosB, MICAz and IMote2. ?? 2008 IEEE.

  10. Surface acoustic wave devices as passive buried sensors

    NASA Astrophysics Data System (ADS)

    Friedt, J.-M.; Rétornaz, T.; Alzuaga, S.; Baron, T.; Martin, G.; Laroche, T.; Ballandras, S.; Griselin, M.; Simonnet, J.-P.

    2011-02-01

    Surface acoustic wave (SAW) devices are currently used as passive remote-controlled sensors for measuring various physical quantities through a wireless link. Among the two main classes of designs—resonator and delay line—the former has the advantage of providing narrow-band spectrum informations and hence appears compatible with an interrogation strategy complying with Industry-Scientific-Medical regulations in radio-frequency (rf) bands centered around 434, 866, or 915 MHz. Delay-line based sensors require larger bandwidths as they consists of a few interdigitated electrodes excited by short rf pulses with large instantaneous energy and short response delays but is compatible with existing equipment such as ground penetrating radar (GPR). We here demonstrate the measurement of temperature using the two configurations, particularly for long term monitoring using sensors buried in soil. Although we have demonstrated long term stability and robustness of packaged resonators and signal to noise ratio compatible with the expected application, the interrogation range (maximum 80 cm) is insufficient for most geology or geophysical purposes. We then focus on the use of delay lines, as the corresponding interrogation method is similar to the one used by GPR which allows for rf penetration distances ranging from a few meters to tens of meters and which operates in the lower rf range, depending on soil water content, permittivity, and conductivity. Assuming propagation losses in a pure dielectric medium with negligible conductivity (snow or ice), an interrogation distance of about 40 m is predicted, which overcomes the observed limits met when using interrogation methods specifically developed for wireless SAW sensors, and could partly comply with the above-mentioned applications. Although quite optimistic, this estimate is consistent with the signal to noise ratio observed during an experimental demonstration of the interrogation of a delay line buried at a depth of 5

  11. Gas sensor technology at Sandia National Laboratories: Catalytic gate, Surface Acoustic Wave and Fiber Optic Devices

    SciTech Connect

    Hughes, R.C.; Moreno, D.J.; Jenkins, M.W.; Rodriguez, J.L.

    1993-10-01

    Sandia`s gas sensor program encompasses three separate electronic platforms: Acoustic Wave Devices, Fiber Optic Sensors and sensors based on silicon microelectronic devices. A review of most of these activities was presented recently in a article in Science under the title ``Chemical Microsensors.`` The focus of the program has been on understanding and developing the chemical sensor coatings that are necessary for using these electronic platforms as effective chemical sensors.

  12. Comparison study of time reversal OFDM acoustic communication with vector and scalar sensors

    NASA Astrophysics Data System (ADS)

    Wang, Zhongkang; Zhang, Hongtao; Xie, Zhe

    2012-11-01

    To compare the performance of time reversal orthogonal frequency division multiplexing (OFDM) acoustic communication on vector and scalar sensors, the vector and scalar acoustic fields were modeled. Time reversal OFDM acoustic communication was then simulated for each sensor type. These results are compared with data from the CAPEx'09 experiment. The abilityof particle velocity channels to achieve reliable acoustic communication, as predicted by the model, is confirmed with the experiment data. Experimental results show that vector receivers can reduce the required array size, in comparisonto hydrophone arrays, whileproviding comparable communication performance.

  13. Routing protocols in wireless sensor networks.

    PubMed

    Villalba, Luis Javier García; Orozco, Ana Lucila Sandoval; Cabrera, Alicia Triviño; Abbas, Cláudia Jacy Barenco

    2009-01-01

    The applications of wireless sensor networks comprise a wide variety of scenarios. In most of them, the network is composed of a significant number of nodes deployed in an extensive area in which not all nodes are directly connected. Then, the data exchange is supported by multihop communications. Routing protocols are in charge of discovering and maintaining the routes in the network. However, the appropriateness of a particular routing protocol mainly depends on the capabilities of the nodes and on the application requirements. This paper presents a review of the main routing protocols proposed for wireless sensor networks. Additionally, the paper includes the efforts carried out by Spanish universities on developing optimization techniques in the area of routing protocols for wireless sensor networks. PMID:22291515

  14. Routing Protocols in Wireless Sensor Networks

    PubMed Central

    Villalba, Luis Javier García; Orozco, Ana Lucila Sandoval; Cabrera, Alicia Triviño; Abbas, Cláudia Jacy Barenco

    2009-01-01

    The applications of wireless sensor networks comprise a wide variety of scenarios. In most of them, the network is composed of a significant number of nodes deployed in an extensive area in which not all nodes are directly connected. Then, the data exchange is supported by multihop communications. Routing protocols are in charge of discovering and maintaining the routes in the network. However, the appropriateness of a particular routing protocol mainly depends on the capabilities of the nodes and on the application requirements. This paper presents a review of the main routing protocols proposed for wireless sensor networks. Additionally, the paper includes the efforts carried out by Spanish universities on developing optimization techniques in the area of routing protocols for wireless sensor networks. PMID:22291515

  15. Acoustic Network Localization and Interpretation of Infrasonic Pulses from Lightning

    NASA Astrophysics Data System (ADS)

    Arechiga, R. O.; Johnson, J. B.; Badillo, E.; Michnovicz, J. C.; Thomas, R. J.; Edens, H. E.; Rison, W.

    2011-12-01

    We improve on the localization accuracy of thunder sources and identify infrasonic pulses that are correlated across a network of acoustic arrays. We attribute these pulses to electrostatic charge relaxation (collapse of the electric field) and attempt to model their spatial extent and acoustic source strength. Toward this objective we have developed a single audio range (20-15,000 Hz) acoustic array and a 4-station network of broadband (0.01-500 Hz) microphone arrays with aperture of ~45 m. The network has an aperture of 1700 m and was installed during the summers of 2009-2011 in the Magdalena mountains of New Mexico, an area that is subject to frequent lightning activity. We are exploring a new technique based on inverse theory that integrates information from the audio range and the network of broadband acoustic arrays to locate thunder sources more accurately than can be achieved with a single array. We evaluate the performance of the technique by comparing the location of thunder sources with RF sources located by the lightning mapping array (LMA) of Langmuir Laboratory at New Mexico Tech. We will show results of this technique for lightning flashes that occurred in the vicinity of our network of acoustic arrays and over the LMA. We will use acoustic network detection of infrasonic pulses together with LMA data and electric field measurements to estimate the spatial distribution of the charge (within the cloud) that is used to produce a lightning flash, and will try to quantify volumetric charges (charge magnitude) within clouds.

  16. Robust, Distributed Target Tracking Using Sensor Network

    NASA Astrophysics Data System (ADS)

    Neema, Kartavya

    Distributed target tracking using sensor networks is crucial for supporting a variety of applications such as battlefield monitoring, weather monitoring, and air traffic management. This dissertation presents a problem formulation and solution approach for distributed target tracking, comprising of sensor fusion and sensor target allocation problems, in the presence of faults in the sensor measurements. There are times when an architecture with central node is preferred but other times when distributed is necessary, we seek a distributed case that can approach the attractive features of centralized case. Therefore, we propose that the underlying two-fold goals of the distributed target tracking problem is to: (1) reach a consensus in the allocation decisions across the sensor network, and (2) achieve a consensus in the state estimates across all the sensors in the network. These goals ensure that each sensor node has the same information across the sensor network, and any node can behave as a central node. In the process of achieving our goals, we develop two new algorithms, one for distributed sensor-target allocation and another for distributed sensor fusion. The Dual Phase Consensus Algorithm (DPCA) for distributed sensor target allocation is a real time algorithm that works in two phases. The first phase of DPCA is similar to distributed sequential greedy search that combines the benefits of greedy and consensus algorithms to reach a feasible solution. The second phase iteratively improves the allocation eventually leading toward a global optimum. DPCA converges to a feasible solution at the order of number of sensors, and thus can be useful for implementation in real time systems. For distributed sensor fusion, we extend the state-of-art distributed Kalman filtering technique called Generalized Kalman Consensus Filter (GKCF), and make it robust against faults present in the sensor measurements. We particularly focus on two types of faults: (1) outliers in the

  17. Planning and Scheduling for Environmental Sensor Networks

    NASA Astrophysics Data System (ADS)

    Frank, J. D.

    2005-12-01

    Environmental Sensor Networks are a new way of monitoring the environment. They comprise autonomous sensor nodes in the environment that record real-time data, which is retrieved, analyzed, integrated with other data sets (e.g. satellite images, GIS, process models) and ultimately lead to scientific discoveries. Sensor networks must operate within time and resource constraints. Sensors have limited onboard memory, energy, computational power, communications windows and communications bandwidth. The value of data will depend on when, where and how it was collected, how detailed the data is, how long it takes to integrate the data, and how important the data was to the original scientific question. Planning and scheduling of sensor networks is necessary for effective, safe operations in the face of these constraints. For example, power bus limitations may preclude sensors from simultaneously collecting data and communicating without damaging the sensor; planners and schedulers can ensure these operations are ordered so that they do not happen simultaneously. Planning and scheduling can also ensure best use of the sensor network to maximize the value of collected science data. For example, if data is best recorded using a particular camera angle but it is costly in time and energy to achieve this, planners and schedulers can search for times when time and energy are available to achieve the optimal camera angle. Planning and scheduling can handle uncertainty in the problem specification; planners can be re-run when new information is made available, or can generate plans that include contingencies. For example, if bad weather may prevent the collection of data, a contingent plan can check lighting conditions and turn off data collection to save resources if lighting is not ideal. Both mobile and immobile sensors can benefit from planning and scheduling. For example, data collection on otherwise passive sensors can be halted to preserve limited power and memory

  18. An all fiber-optic sensor for surface acoustic wave measurements

    NASA Technical Reports Server (NTRS)

    Bowers, J. E.; Jungerman, R. L.; Khuri-Yakub, B. T.; Kino, G. S.

    1983-01-01

    A surface acoustic wave (SAW) sensor constructed from single-mode fiber-optic components is described. An analysis of reciprocal and nonreciprocal modes of operation of the sensor is presented. Results from measurements on a variety of SAW devices illustrate the use of the sensor. The amplitude sensitivity is 0.0003 A for an integration time of 0.1 s.

  19. Acoustic target detection and classification using neural networks

    NASA Technical Reports Server (NTRS)

    Robertson, James A.; Conlon, Mark

    1993-01-01

    A neural network approach to the classification of acoustic emissions of ground vehicles and helicopters is demonstrated. Data collected during the Joint Acoustic Propagation Experiment conducted in July of l991 at White Sands Missile Range, New Mexico was used to train a classifier to distinguish between the spectrums of a UH-1, M60, M1 and M114. An output node was also included that would recognize background (i.e. no target) data. Analysis revealed specific hidden nodes responding to the features input into the classifier. Initial results using the neural network were encouraging with high correct identification rates accompanied by high levels of confidence.

  20. JSC Wireless Sensor Network Update

    NASA Technical Reports Server (NTRS)

    Wagner, Robert

    2010-01-01

    Sensor nodes composed of three basic components... radio module: COTS radio module implementing standardized WSN protocol; treated as WSN modem by main board main board: contains application processor (TI MSP430 microcontroller), memory, power supply; responsible for sensor data acquisition, pre-processing, and task scheduling; re-used in every application with growing library of embedded C code sensor card: contains application-specific sensors, data conditioning hardware, and any advanced hardware not built into main board (DSPs, faster A/D, etc.); requires (re-) development for each application.

  1. Embedded and conventional ultrasonic sensors for monitoring acoustic emission during thermal fatigue

    NASA Astrophysics Data System (ADS)

    Trujillo, Blaine; Zagrai, Andrei

    2016-04-01

    Acoustic emission is widely used for monitoring pressure vessels, pipes, critical infrastructure, as well as land, sea and air vehicles. It is one of dominant approaches to explore material degradation under fatigue and events leading to material fracture. Addressing a recent interest in structural health monitoring of space vehicles, a need has emerged to evaluate material deterioration due to thermal fatigue during spacecraft atmospheric reentry. Thermal fatigue experiments were conducted, in which aluminum plates were subjected to localized heating and acoustic emission was monitoring by embedded and conventional acoustic emission sensors positioned at various distances from a heat source. At the same time, surface temperature of aluminum plates was monitored using an IR camera. Acoustic emission counts collected by embedded sensors were compared to counts measured with conventional acoustic emission sensors. Both types of sensors show noticeable increase of acoustic emission activity as localized heating source was applied to aluminum plates. Experimental data demonstrate correlation between temperature increase on the surface of the plates and increase in measured acoustic emission activity. It is concluded that under particular conditions, embedded piezoelectric wafer active sensors can be used for acoustic emission monitoring of thermally-induced structural degradation.

  2. Simulating Operation of a Complex Sensor Network

    NASA Technical Reports Server (NTRS)

    Jennings, Esther; Clare, Loren; Woo, Simon

    2008-01-01

    Simulation Tool for ASCTA Microsensor Network Architecture (STAMiNA) ["ASCTA" denotes the Advanced Sensors Collaborative Technology Alliance.] is a computer program for evaluating conceptual sensor networks deployed over terrain to provide military situational awareness. This or a similar program is needed because of the complexity of interactions among such diverse phenomena as sensing and communication portions of a network, deployment of sensor nodes, effects of terrain, data-fusion algorithms, and threat characteristics. STAMiNA is built upon a commercial network-simulator engine, with extensions to include both sensing and communication models in a discrete-event simulation environment. Users can define (1) a mission environment, including terrain features; (2) objects to be sensed; (3) placements and modalities of sensors, abilities of sensors to sense objects of various types, and sensor false alarm rates; (4) trajectories of threatening objects; (5) means of dissemination and fusion of data; and (6) various network configurations. By use of STAMiNA, one can simulate detection of targets through sensing, dissemination of information by various wireless communication subsystems under various scenarios, and fusion of information, incorporating such metrics as target-detection probabilities, false-alarm rates, and communication loads, and capturing effects of terrain and threat.

  3. Wireless sensor networks for active vibration control in automobile structures

    NASA Astrophysics Data System (ADS)

    Mieyeville, Fabien; Ichchou, Mohamed; Scorletti, Gérard; Navarro, David; Du, Wan

    2012-07-01

    Wireless sensor networks (WSNs) are nowadays widely used in monitoring and tracking applications. This paper presents the feasibility of using WSNs in active vibration control strategies. The method employed here involves active-structural acoustic control using piezoelectric sensors distributed on a car structure. This system aims at being merged with a WSN whose head node collects data and processes control laws so as to command piezoelectric actuators wisely placed on the structure. We will study the feasibility of implementing WSNs in active vibration control and introduce a complete design methodology to optimize hardware/software and control law synergy in mechatronic systems. A design space exploration will be conducted so as to identify the best WSN platform and the resulting impact on control.

  4. Wireless Sensor Networks for Ambient Assisted Living

    PubMed Central

    Aquino-Santos, Raúl; Martinez-Castro, Diego; Edwards-Block, Arthur; Murillo-Piedrahita, Andrés Felipe

    2013-01-01

    This paper introduces wireless sensor networks for Ambient Assisted Living as a proof of concept. Our workgroup has developed an arrhythmia detection algorithm that we evaluate in a closed space using a wireless sensor network to relay the information collected to where the information can be registered, monitored and analyzed to support medical decisions by healthcare providers. The prototype we developed is then evaluated using the TelosB platform. The proposed architecture considers very specific restrictions regarding the use of wireless sensor networks in clinical situations. The seamless integration of the system architecture enables both mobile node and network configuration, thus providing the versatile and robust characteristics necessary for real-time applications in medical situations. Likewise, this system architecture efficiently permits the different components of our proposed platform to interact efficiently within the parameters of this study. PMID:24351665

  5. Wireless sensor networks for ambient assisted living.

    PubMed

    Aquino-Santos, Raúl; Martinez-Castro, Diego; Edwards-Block, Arthur; Murillo-Piedrahita, Andrés Felipe

    2013-11-29

    This paper introduces wireless sensor networks for Ambient Assisted Living as a proof of concept. Our workgroup has developed an arrhythmia detection algorithm that we evaluate in a closed space using a wireless sensor network to relay the information collected to where the information can be registered, monitored and analyzed to support medical decisions by healthcare providers. The prototype we developed is then evaluated using the TelosB platform. The proposed architecture considers very specific restrictions regarding the use of wireless sensor networks in clinical situations. The seamless integration of the system architecture enables both mobile node and network configuration, thus providing the versatile and robust characteristics necessary for real-time applications in medical situations. Likewise, this system architecture efficiently permits the different components of our proposed platform to interact efficiently within the parameters of this study.

  6. a Low-Power Wireless Sensor Network for Monitoring the Microcrack Initiations in Aerospace Composites

    NASA Astrophysics Data System (ADS)

    Li, Jian; Plotnikov, Yuri; Lin, Wendy W.

    2008-02-01

    A low power wireless sensor network was developed to monitor the microcrack events in aerospace composites. The microcracks in the composites mostly result from a stress loading or temperature and/or humidity cycles. Generally, a single microcrack is too small to be detected by conventional techniques such as X-ray or ultrasonic C-scan. The whole developed sensor network is aimed to capture the released acoustic signals by the microcracking events in real time. It comprises of a receiving station as well as a series of sensor nodes. Each sensor node includes two acoustic emission transducers as well as two signal amplification and data acquisition channels. Much of our development effort has been focused on reducing the power consumption of each node and improving the detection reliability for each event. Each sensor node is battery-powered and works in a sleep mode most of time. Once a microcrack is initiated in the composite, the acoustic signal triggers the node and wakes it up. The node will then react in several microseconds and digitize the signal. The digitized data is sent to the station wirelessly. The developed wireless sensor network system has been validated with microscopy of microcracked samples after temperature and humidity cycling and has proved to be an effective tool for microcracking detection. Furthermore, our low power consumption design and sophisticated wireless transmission mechanism enables a system with great potential for field structural health monitoring applications.

  7. Identification of cavitation signatures using both optical and PZT acoustic sensors

    NASA Astrophysics Data System (ADS)

    Vidakovic, M.; Armakolas, I.; Sun, T.; Carlton, J.; Grattan, K. T. V.

    2015-09-01

    This paper presents the results obtained from monitoring a simulated material cavitation process using both a fibre Bragg grating (FBG)-based acoustic sensor system developed at City University London and a commercial PZT (Piezoelectric Transducer) acoustic sensor, with an aim to identify the cavitation signatures. In the experiment, a sample metal plate with its back surface being instrumented with both sensors is positioned very close to an excitation sonotrode with a standard frequency of 19.5kHz. The data obtained from both sensors are recorded and analyzed, showing a very good agreement.

  8. Investigation of a stall deterrent system utilizing an acoustic stall sensor

    NASA Technical Reports Server (NTRS)

    Bennett, A. G.; Owens, J. K.; Harris, R. L.

    1977-01-01

    A simple rugged acoustic stall sensor which has an output proportional to angle of attack near wing stall has been evaluated on a Cessna 319 aircraft. A sensor position has been found on the wing where the sensor output is only slightly affected by engine power level, yaw angle, flap position and wing roughness. The NASA LRC General Aviation Simulator has been used to evaluate the acoustic sensor output as a control signal for active stall deterrent systems. It has been found that a simple control algorithm is sufficient for stall deterrence.

  9. Investigation of acoustic sensors to detect coconut rhinoceros beetle in Guam

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The coconut rhinoceros beetle, Oryctes rhinoceros, was accidentally introduced into Guam last year and now threatens the Island’s forests and tourist industry. These large insects can be detected easily with acoustic sensors, and procedures are being developed to incorporate acoustic technology int...

  10. Target Coverage in Wireless Sensor Networks with Probabilistic Sensors.

    PubMed

    Shan, Anxing; Xu, Xianghua; Cheng, Zongmao

    2016-01-01

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

  11. Target Coverage in Wireless Sensor Networks with Probabilistic Sensors

    PubMed Central

    Shan, Anxing; Xu, Xianghua; Cheng, Zongmao

    2016-01-01

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

  12. In-Network Processing of Joins in Wireless Sensor Networks

    PubMed Central

    Kang, Hyunchul

    2013-01-01

    The join or correlated filtering of sensor readings is one of the fundamental query operations in wireless sensor networks (WSNs). Although the join in centralized or distributed databases is a well-researched problem, join processing in WSNs has quite different characteristics and is much more difficult to perform due to the lack of statistics on sensor readings and the resource constraints of sensor nodes. Since data transmission is orders of magnitude more costly than processing at a sensor node, in-network processing of joins is essential. In this paper, the state-of-the-art techniques for join implementation in WSNs are surveyed. The requirements and challenges, join types, and components of join implementation are described. The open issues for further research are identified. PMID:23478603

  13. A Stratified Acoustic Model Accounting for Phase Shifts for Underwater Acoustic Networks

    PubMed Central

    Wang, Ping; Zhang, Lin; Li, Victor O. K.

    2013-01-01

    Accurate acoustic channel models are critical for the study of underwater acoustic networks. Existing models include physics-based models and empirical approximation models. The former enjoy good accuracy, but incur heavy computational load, rendering them impractical in large networks. On the other hand, the latter are computationally inexpensive but inaccurate since they do not account for the complex effects of boundary reflection losses, the multi-path phenomenon and ray bending in the stratified ocean medium. In this paper, we propose a Stratified Acoustic Model (SAM) based on frequency-independent geometrical ray tracing, accounting for each ray's phase shift during the propagation. It is a feasible channel model for large scale underwater acoustic network simulation, allowing us to predict the transmission loss with much lower computational complexity than the traditional physics-based models. The accuracy of the model is validated via comparisons with the experimental measurements in two different oceans. Satisfactory agreements with the measurements and with other computationally intensive classical physics-based models are demonstrated. PMID:23669708

  14. Fiber Optic Sensor for Acoustic Detection of Partial Discharges in Oil-Paper Insulated Electrical Systems

    PubMed Central

    Posada-Roman, Julio; Garcia-Souto, Jose A.; Rubio-Serrano, Jesus

    2012-01-01

    A fiber optic interferometric sensor with an intrinsic transducer along a length of the fiber is presented for ultrasound measurements of the acoustic emission from partial discharges inside oil-filled power apparatus. The sensor is designed for high sensitivity measurements in a harsh electromagnetic field environment, with wide temperature changes and immersion in oil. It allows enough sensitivity for the application, for which the acoustic pressure is in the range of units of Pa at a frequency of 150 kHz. In addition, the accessibility to the sensing region is guaranteed by immune fiber-optic cables and the optical phase sensor output. The sensor design is a compact and rugged coil of fiber. In addition to a complete calibration, the in-situ results show that two types of partial discharges are measured through their acoustic emissions with the sensor immersed in oil. PMID:22666058

  15. Integrating Sensors and Social Networks

    NASA Astrophysics Data System (ADS)

    Aggarwal, Charu C.; Abdelzaher, Tarek

    A number of sensor applications in recent years collect data which can be directly associated with human interactions. Some examples of such applications include GPS applications on mobile devices, accelerometers, or location sensors designed to track human and vehicular traffic. Such data lends itself to a variety of rich applications in which one can use the sensor data in order to model the underlying relationships and interactions. It also leads to a number of challenges, since such data may often be private, and it is important to be able to perform the mining process without violating the privacy of the users. In this chapter, we provide a broad survey of the work in this important and rapidly emerging field. We also discuss the key problems which arise in the context of this important field and the corresponding solutions.

  16. Denoising of human speech using combined acoustic and em sensor signal processing

    SciTech Connect

    Ng, L C; Burnett, G C; Holzrichter, J F; Gable, T J

    1999-11-29

    Low Power EM radar-like sensors have made it possible to measure properties of the human speech production system in real-time, without acoustic interference. This greatly enhances the quality and quantify of information for many speech related applications. See Holzrichter, Burnett, Ng, and Lea, J. Acoustic. Soc. Am. 103 (1) 622 (1998). By using combined Glottal-EM- Sensor- and Acoustic-signals, segments of voiced, unvoiced, and no-speech can be reliably defined. Real-time Denoising filters can be constructed to remove noise from the user's corresponding speech signal.

  17. The human immunodeficiency virus reduces network capacity: acoustic noise effect

    PubMed Central

    Tomasi, Dardo; Chang, Linda; de Castro Caparelli, Elisabeth; Telang, Frank; Ernst, Thomas

    2008-01-01

    Increased acoustic noise (AN) during working memory (WM) leads to increased brain activation in healthy individuals, and may have greater impact in human immunodeficiency virus (HIV) patients. Compared to controls, HIV subjects showed reduced AN-activation and lower neuronal marker N-acetylaspartate in prefrontal and parietal cortices. Competing use of the WM network between AN and cognitive load showed lower dynamic range of the hemodynamic responses in prefrontal and parietal cortices in HIV patients. These findings suggest reduced reserve capacity of the WM network in HIV patients and additional stress (e.g. AN) might exhaust the impaired network for more demanding tasks. PMID:16437575

  18. Sensor Anomaly Detection in Wireless Sensor Networks for Healthcare

    PubMed Central

    Haque, Shah Ahsanul; Rahman, Mustafizur; Aziz, Syed Mahfuzul

    2015-01-01

    Wireless Sensor Networks (WSN) are vulnerable to various sensor faults and faulty measurements. This vulnerability hinders efficient and timely response in various WSN applications, such as healthcare. For example, faulty measurements can create false alarms which may require unnecessary intervention from healthcare personnel. Therefore, an approach to differentiate between real medical conditions and false alarms will improve remote patient monitoring systems and quality of healthcare service afforded by WSN. In this paper, a novel approach is proposed to detect sensor anomaly by analyzing collected physiological data from medical sensors. The objective of this method is to effectively distinguish false alarms from true alarms. It predicts a sensor value from historic values and compares it with the actual sensed value for a particular instance. The difference is compared against a threshold value, which is dynamically adjusted, to ascertain whether the sensor value is anomalous. The proposed approach has been applied to real healthcare datasets and compared with existing approaches. Experimental results demonstrate the effectiveness of the proposed system, providing high Detection Rate (DR) and low False Positive Rate (FPR). PMID:25884786

  19. Wireless sensors and sensor networks for homeland security applications

    PubMed Central

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

    2012-01-01

    New sensor technologies for homeland security applications must meet the key requirements of sensitivity to detect agents below risk levels, selectivity to provide minimal false-alarm rates, and response speed to operate in high throughput environments, such as airports, sea ports, and other public places. Chemical detection using existing sensor systems is facing a major challenge of selectivity. In this review, we provide a brief summary of chemical threats of homeland security importance; focus in detail on modern concepts in chemical sensing; examine the origins of the most significant unmet needs in existing chemical sensors; and, analyze opportunities, specific requirements, and challenges for wireless chemical sensors and wireless sensor networks (WSNs). We further review a new approach for selective chemical sensing that involves the combination of a sensing material that has different response mechanisms to different species of interest, with a transducer that has a multi-variable signal-transduction ability. This new selective chemical-sensing approach was realized using an attractive ubiquitous platform of battery-free passive radio-frequency identification (RFID) tags adapted for chemical sensing. We illustrate the performance of RFID sensors developed in measurements of toxic industrial materials, humidity-independent detection of toxic vapors, and detection of chemical-agent simulants, explosives, and strong oxidizers. PMID:23175590

  20. A Fibre Bragg Grating Sensor as a Receiver for Acoustic Communications Signals

    PubMed Central

    Wild, Graham; Hinckley, Steven

    2011-01-01

    A Fibre Bragg Grating (FBG) acoustic sensor is used as a receiver for acoustic communications signals. Acoustic transmissions were generated in aluminium and Carbon Fibre Composite (CFC) panels. The FBG receiver was coupled to the bottom surface opposite a piezoelectric transmitter. For the CFC, a second FBG was embedded within the layup for comparison. We show the transfer function, frequency response, and transient response of the acoustic communications channels. In addition, the FBG receiver was used to detect Phase Shift Keying (PSK) communications signals, which was shown to be the most robust method in a highly resonant communications channel. PMID:22346585

  1. EMMNet: Sensor Networking for Electricity Meter Monitoring

    PubMed Central

    Lin, Zhi-Ting; Zheng, Jie; Ji, Yu-Sheng; Zhao, Bao-Hua; Qu, Yu-Gui; Huang, Xu-Dong; Jiang, Xiu-Fang

    2010-01-01

    Smart sensors are emerging as a promising technology for a large number of application domains. This paper presents a collection of requirements and guidelines that serve as a basis for a general smart sensor architecture to monitor electricity meters. It also presents an electricity meter monitoring network, named EMMNet, comprised of data collectors, data concentrators, hand-held devices, a centralized server, and clients. EMMNet provides long-distance communication capabilities, which make it suitable suitable for complex urban environments. In addition, the operational cost of EMMNet is low, compared with other existing remote meter monitoring systems based on GPRS. A new dynamic tree protocol based on the application requirements which can significantly improve the reliability of the network is also proposed. We are currently conducting tests on five networks and investigating network problems for further improvements. Evaluation results indicate that EMMNet enhances the efficiency and accuracy in the reading, recording, and calibration of electricity meters. PMID:22163551

  2. EMMNet: sensor networking for electricity meter monitoring.

    PubMed

    Lin, Zhi-Ting; Zheng, Jie; Ji, Yu-Sheng; Zhao, Bao-Hua; Qu, Yu-Gui; Huang, Xu-Dong; Jiang, Xiu-Fang

    2010-01-01

    Smart sensors are emerging as a promising technology for a large number of application domains. This paper presents a collection of requirements and guidelines that serve as a basis for a general smart sensor architecture to monitor electricity meters. It also presents an electricity meter monitoring network, named EMMNet, comprised of data collectors, data concentrators, hand-held devices, a centralized server, and clients. EMMNet provides long-distance communication capabilities, which make it suitable suitable for complex urban environments. In addition, the operational cost of EMMNet is low, compared with other existing remote meter monitoring systems based on GPRS. A new dynamic tree protocol based on the application requirements which can significantly improve the reliability of the network is also proposed. We are currently conducting tests on five networks and investigating network problems for further improvements. Evaluation results indicate that EMMNet enhances the efficiency and accuracy in the reading, recording, and calibration of electricity meters.

  3. Acoustic-wave sensor for ambient monitoring of a photoresist-stripping agent

    DOEpatents

    Pfeifer, K.B.; Hoyt, A.E.; Frye, G.C.

    1998-08-18

    The acoustic-wave sensor is disclosed. The acoustic-wave sensor is designed for ambient or vapor-phase monitoring of a photoresist-stripping agent such as N-methylpyrrolidinone (NMP), ethoxyethylpropionate (EEP) or the like. The acoustic-wave sensor comprises an acoustic-wave device such as a surface-acoustic-wave (SAW) device, a flexural-plate-wave (FPW) device, an acoustic-plate-mode (APM) device, or a thickness-shear-mode (TSM) device (also termed a quartz crystal microbalance or QCM) having a sensing region on a surface thereof. The sensing region includes a sensing film for sorbing a quantity of the photoresist-stripping agent, thereby altering or shifting a frequency of oscillation of an acoustic wave propagating through the sensing region for indicating an ambient concentration of the agent. According to preferred embodiments of the invention, the acoustic-wave device is a SAW device; and the sensing film comprises poly(vinylacetate), poly(N-vinylpyrrolidinone), or poly(vinylphenol). 3 figs.

  4. Acoustic-wave sensor for ambient monitoring of a photoresist-stripping agent

    DOEpatents

    Pfeifer, Kent B.; Hoyt, Andrea E.; Frye, Gregory C.

    1998-01-01

    The acoustic-wave sensor. The acoustic-wave sensor is designed for ambient or vapor-phase monitoring of a photoresist-stripping agent such as N-methylpyrrolidinone (NMP), ethoxyethylpropionate (EEP) or the like. The acoustic-wave sensor comprises an acoustic-wave device such as a surface-acoustic-wave (SAW) device, a flexural-plate-wave (FPW) device, an acoustic-plate-mode (APM) device, or a thickness-shear-mode (TSM) device (also termed a quartz crystal microbalance or QCM) having a sensing region on a surface thereof. The sensing region includes a sensing film for sorbing a quantity of the photoresist-stripping agent, thereby altering or shifting a frequency of oscillation of an acoustic wave propagating through the sensing region for indicating an ambient concentration of the agent. According to preferred embodiments of the invention, the acoustic-wave device is a SAW device; and the sensing film comprises poly(vinylacetate), poly(N-vinylpyrrolidinone), or poly(vinylphenol).

  5. Optimizing Retransmission Threshold in Wireless Sensor Networks.

    PubMed

    Bi, Ran; Li, Yingshu; Tan, Guozhen; Sun, Liang

    2016-01-01

    The retransmission threshold in wireless sensor networks is critical to the latency of data delivery in the networks. However, existing works on data transmission in sensor networks did not consider the optimization of the retransmission threshold, and they simply set the same retransmission threshold for all sensor nodes in advance. The method did not take link quality and delay requirement into account, which decreases the probability of a packet passing its delivery path within a given deadline. This paper investigates the problem of finding optimal retransmission thresholds for relay nodes along a delivery path in a sensor network. The object of optimizing retransmission thresholds is to maximize the summation of the probability of the packet being successfully delivered to the next relay node or destination node in time. A dynamic programming-based distributed algorithm for finding optimal retransmission thresholds for relay nodes along a delivery path in the sensor network is proposed. The time complexity is O n Δ · max 1 ≤ i ≤ n { u i } , where u i is the given upper bound of the retransmission threshold of sensor node i in a given delivery path, n is the length of the delivery path and Δ is the given upper bound of the transmission delay of the delivery path. If Δ is greater than the polynomial, to reduce the time complexity, a linear programming-based ( 1 + p m i n ) -approximation algorithm is proposed. Furthermore, when the ranges of the upper and lower bounds of retransmission thresholds are big enough, a Lagrange multiplier-based distributed O ( 1 ) -approximation algorithm with time complexity O ( 1 ) is proposed. Experimental results show that the proposed algorithms have better performance. PMID:27171092

  6. Optimizing Retransmission Threshold in Wireless Sensor Networks

    PubMed Central

    Bi, Ran; Li, Yingshu; Tan, Guozhen; Sun, Liang

    2016-01-01

    The retransmission threshold in wireless sensor networks is critical to the latency of data delivery in the networks. However, existing works on data transmission in sensor networks did not consider the optimization of the retransmission threshold, and they simply set the same retransmission threshold for all sensor nodes in advance. The method did not take link quality and delay requirement into account, which decreases the probability of a packet passing its delivery path within a given deadline. This paper investigates the problem of finding optimal retransmission thresholds for relay nodes along a delivery path in a sensor network. The object of optimizing retransmission thresholds is to maximize the summation of the probability of the packet being successfully delivered to the next relay node or destination node in time. A dynamic programming-based distributed algorithm for finding optimal retransmission thresholds for relay nodes along a delivery path in the sensor network is proposed. The time complexity is OnΔ·max1≤i≤n{ui}, where ui is the given upper bound of the retransmission threshold of sensor node i in a given delivery path, n is the length of the delivery path and Δ is the given upper bound of the transmission delay of the delivery path. If Δ is greater than the polynomial, to reduce the time complexity, a linear programming-based (1+pmin)-approximation algorithm is proposed. Furthermore, when the ranges of the upper and lower bounds of retransmission thresholds are big enough, a Lagrange multiplier-based distributed O(1)-approximation algorithm with time complexity O(1) is proposed. Experimental results show that the proposed algorithms have better performance. PMID:27171092

  7. Networked localization of sniper shots using acoustics

    NASA Astrophysics Data System (ADS)

    Hengy, S.; Hamery, P.; De Mezzo, S.; Duffner, P.

    2011-06-01

    The presence of snipers in modern conflicts leads to high insecurity for the soldiers. In order to improve the soldier's protection against this threat, the French German Research Institute of Saint-Louis (ISL) initiated studies in the domain of acoustic localization of shots. Mobile antennas mounted on the soldier's helmet were initially used for real-time detection, classification and localization of sniper shots. It showed good performances in land scenarios, but also in urban scenarios if the array was in the shot corridor, meaning that the microphones first detect the direct wave and then the reflections of the Mach and muzzle waves. As soon as the acoustic arrays were not near to the shot corridor (only reflections are detected) this solution lost its efficiency and erroneous estimated position were given. In order to estimate the position of the shooter in every kind of urban scenario, ISL started studying time reversal techniques. Knowing the position of every reflective object in the environment (buildings, walls, ...) it should be possible to estimate the position of the shooter. First, a synthetic propagation algorithm has been developed and validated for real scale applications. It has then been validated for small scale models, allowing us to test our time reversal based algorithms in our laboratory. In this paper we discuss all the challenges that are induced by the application of sniper detection using time reversal techniques. We will discuss all the hard points that can be encountered and try to find some solutions in order to optimize the use of this technique.

  8. Group scheduling problems in directional sensor networks

    NASA Astrophysics Data System (ADS)

    Singh, Alok; Rossi, André

    2015-12-01

    This article addresses the problem of scheduling a set of groups of directional sensors arising as a result of applying an exact or a heuristic approach for solving a problem involving directional sensors. The problem seeks a schedule for these groups that minimizes the total energy consumed in switching from one group to the next group in the schedule. In practice, when switching from a group to the next one, active sensors in the new group have to rotate in order to face their working direction. These rotations consume energy, and the problem is to schedule the groups so as to minimize the total amount of energy consumed by all the sensor rotations, knowing the initial angular positions of all the sensors. In this article, it is assumed that energy consumption is proportional to the angular movement for all the sensors. Another problem version is also investigated that seeks to minimize the total time during which the sensor network cannot cover all the targets because active sensors are rotating. Both problems are proved to be ?-hard, and a lower bound for the first problem is presented. A greedy heuristic and a genetic algorithm are also proposed for addressing the problem of minimizing total rotation in the general case. Finally, a local search is also proposed to improve the solutions obtained through a genetic algorithm.

  9. Toward controlling perturbations in robotic sensor networks

    NASA Astrophysics Data System (ADS)

    Banerjee, Ashis G.; Majumder, Saikat R.

    2014-06-01

    Robotic sensor networks (RSNs), which consist of networks of sensors placed on mobile robots, are being increasingly used for environment monitoring applications. In particular, a lot of work has been done on simultaneous localization and mapping of the robots, and optimal sensor placement for environment state estimation1. The deployment of RSNs, however, remains challenging in harsh environments where the RSNs have to deal with significant perturbations in the forms of wind gusts, turbulent water flows, sand storms, or blizzards that disrupt inter-robot communication and individual robot stability. Hence, there is a need to be able to control such perturbations and bring the networks to desirable states with stable nodes (robots) and minimal operational performance (environment sensing). Recent work has demonstrated the feasibility of controlling the non-linear dynamics in other communication networks like emergency management systems and power grids by introducing compensatory perturbations to restore network stability and operation2. In this paper, we develop a computational framework to investigate the usefulness of this approach for RSNs in marine environments. Preliminary analysis shows promising performance and identifies bounds on the original perturbations within which it is possible to control the networks.

  10. Cooperative UAV-Based Communications Backbone for Sensor Networks

    SciTech Connect

    Roberts, R S

    2001-10-07

    The objective of this project is to investigate the use of unmanned air vehicles (UAVs) as mobile, adaptive communications backbones for ground-based sensor networks. In this type of network, the UAVs provide communication connectivity to sensors that cannot communicate with each other because of terrain, distance, or other geographical constraints. In these situations, UAVs provide a vertical communication path for the sensors, thereby mitigating geographic obstacles often imposed on networks. With the proper use of UAVs, connectivity to a widely disbursed sensor network in rugged terrain is readily achieved. Our investigation has focused on networks where multiple cooperating UAVs are used to form a network backbone. The advantage of using multiple UAVs to form the network backbone is parallelization of sensor connectivity. Many widely spaced or isolated sensors can be connected to the network at once using this approach. In these networks, the UAVs logically partition the sensor network into sub-networks (subnets), with one UAV assigned per subnet. Partitioning the network into subnets allows the UAVs to service sensors in parallel thereby decreasing the sensor-to-network connectivity. A UAV services sensors in its subnet by flying a route (path) through the subnet, uplinking data collected by the sensors, and forwarding the data to a ground station. An additional advantage of using multiple UAVs in the network is that they provide redundancy in the communications backbone, so that the failure of a single UAV does not necessarily imply the loss of the network.

  11. Sensor Network Demonstration for In Situ Decommissioning - 13332

    SciTech Connect

    Lagos, L.; Varona, J.; Awwad, A.; Rivera, J.; McGill, J.

    2013-07-01

    individual sensors would be immobilized during the grout pouring activities, a set of nine sensor racks were designed. The 270 sensors provided by Idaho National Laboratory (INL), Mississippi State University (MSU), University of Houston (UH), and University of South Carolina (USC) were secured to these racks based on predetermined locations. Once sensor racks were installed inside the test cube, connected and debugged, approximately 32 cubic yards of special grout material was used to entomb the sensors. MSU provided and demonstrated four types of fiber loop ring-down (FLR) sensors for detection of water, temperature, cracks, and movement of fluids. INL provided and demonstrated time differenced 3D electrical resistivity tomography (ERT), advanced tensiometers for moisture content, and thermocouples for temperature measurements. University of Houston provided smart aggregate (SA) sensors, which detect crack severity and water presence. An additional UH sensor system demonstrated was a Fiber Bragg Grating (FBG) fiber optic system measuring strain, presence of water, and temperature. USC provided a system which measured acoustic emissions during cracking, as well as temperature and pH sensors. All systems were connected to a Sensor Remote Access System (SRAS) data networking and collection system designed, developed and provided by FIU. The purpose of SRAS was to collect and allow download of the raw sensor data from all the sensor system, as well as allow upload of the processed data and any analysis reports and graphs. All this information was made available to the research teams via the Deactivation and Decommissioning Knowledge Management and Information Tool (D and D KM-IT). As a current research effort, FIU is performing an energy analysis, and transferring several sensor systems to a Photovoltaic (PV) System to continuously monitor energy consumption parameters and overall power demands. Also, One final component of this research is focusing on developing an integrated

  12. Target tracking for heterogeneous smart sensor networks

    NASA Astrophysics Data System (ADS)

    Bevington, James E.; McDonnell, Timothy X.

    2001-08-01

    Distributed sensor networks will play a key role in the network centric warfighting environments of the future. We envision a ubiquitous sensing `fabric,' comprising sensors distributed over the terrain and carried on manned and unmanned, terrestrial and airborne vehicles. As a complex `system of systems,' this fabric will need to adapt and self-organize to perform a variety of higher-level tasks such as surveillance and target acquisition. The topology and availability of the sensors will be constantly changing, as will the needs of users as dictated by evolving missions and operational environments. In this work, focusing on the task of target tracking, we address approaches for locating and organizing sensing and processing resources and present algorithms for suitably fusing the observations obtained from a varied and changing set of sensors. Run-time discovery and access of new sensing resources are obtained through the use of Java Jini, treating sensing resources as `services' and viewing higher-level processes such as tracking as clients. Algorithms for fusing generic sensor observations for target tracking are based on the extended Kalman filter, while detection and track initiation are based on a new likelihood projection technique. We present results from an implementation of these concepts in a real- time sensor testbed and discuss lessons learned.

  13. The trade-off characteristics of acoustic and pressure sensors for the NASP

    NASA Technical Reports Server (NTRS)

    Winkler, Martin; Bush, Chuck

    1992-01-01

    Results of a trade study for the development of pressure and acoustic sensors for use on the National Aerospace Plane (NASP) are summarized. Pressure sensors are needed to operate to 100 psia; acoustic sensors are needed that can give meaningful information about a 200 dB sound pressure level (SPL) environment. Both sensors will have to operate from a high temperature of 2000 F down to absolute zero. The main conclusions of the study are the following: (1) Diaphragm materials limit minimum size and maximum frequency response attainable. (2) No transduction is available to meet all the NASP requirements with existing technology. (3) Capacitive sensors are large relative to the requirement, have limited resolution and frequency response due to noise, and cable length is limited to approximately 20 feet. (4) Eddy current sensors are large relative to the requirement and have limited cable lengths. (5) Fiber optic sensors provide the possibility for a small sensor, even though present developments do not exhibit that characteristic. The need to use sapphire at high temperature complicates the design. Present high temperature research sensors suffer from poor resolution. A significant development effort will be required to realize the potential of fiber optics. (6) Short-term development seems to favor eddy current techniques with the penalty of larger size and reduced dynamic range for acoustic sensors. (7) Long-term development may favor fiber optics with the penalties of cost, schedule, and uncertainty.

  14. The trade-off characteristics of acoustic and pressure sensors for the NASP

    NASA Astrophysics Data System (ADS)

    Winkler, Martin; Bush, Chuck

    1992-09-01

    Results of a trade study for the development of pressure and acoustic sensors for use on the National Aerospace Plane (NASP) are summarized. Pressure sensors are needed to operate to 100 psia; acoustic sensors are needed that can give meaningful information about a 200 dB sound pressure level (SPL) environment. Both sensors will have to operate from a high temperature of 2000 F down to absolute zero. The main conclusions of the study are the following: (1) Diaphragm materials limit minimum size and maximum frequency response attainable. (2) No transduction is available to meet all the NASP requirements with existing technology. (3) Capacitive sensors are large relative to the requirement, have limited resolution and frequency response due to noise, and cable length is limited to approximately 20 feet. (4) Eddy current sensors are large relative to the requirement and have limited cable lengths. (5) Fiber optic sensors provide the possibility for a small sensor, even though present developments do not exhibit that characteristic. The need to use sapphire at high temperature complicates the design. Present high temperature research sensors suffer from poor resolution. A significant development effort will be required to realize the potential of fiber optics. (6) Short-term development seems to favor eddy current techniques with the penalty of larger size and reduced dynamic range for acoustic sensors. (7) Long-term development may favor fiber optics with the penalties of cost, schedule, and uncertainty.

  15. A Wireless Sensor Network For Soil Monitoring

    NASA Astrophysics Data System (ADS)

    Szlavecz, K.; Cogan, J.; Musaloiu-Elefteri, R.; Small, S.; Terzis, A.; Szalay, A.

    2005-12-01

    The most spatially complex stratum of a terrestrial ecosystem is its soil. Among the major challenges of studying the soil ecosystem are the diversity and the cryptic nature of biota, and the enormous heterogeneity of the soil substrate. Often this patchiness drives spatial distribution of soil organisms, yet our knowledge on the spatio-temporal patterns of soil conditions is limited. To monitor the environmental conditions at biologically meaningful spatial scales we have developed and deployed a wireless sensor network of thirty nodes. Each node is based on a MICAz mote connected to a custom-built sensor suite that includes a Watermark soil moisture sensor, an Irrometer soil temperature sensor, and sensors capable of recording ambient temperature and light intensity. To assess CO2 production at the ground level a subset of the nodes is equipped with Telaire 6004 CO2 sensor. We developed the software running on the motes from scratch, using the TinyOS development environment. Each mote collects measurements every minute, and stores them persistently in a non-volatile memory. The decision to store data locally at each node enables us to reliably retrieve the data in the face of network losses and premature node failures due to power depletion. Collected measurements are retrieved over the wireless network through a PC-class computer acting as a gateway between the sensor network and the Internet. Considering that motes are battery powered, the largest obstacle hindering long-term sensor network deployments is power consumption. To address this problem, our software powers down sensors between sampling cycles and turns off the radio (the most energy prohibitive mote component) when not in use. By doing so we were able to increase node lifetime by a factor of ten. We collected field data over several weeks. The data was ingested into a SQL Server database, which provides data access through a .NET web services interface. The database provides functions for spatial

  16. Clock Synchronization for Multihop Wireless Sensor Networks

    ERIC Educational Resources Information Center

    Solis Robles, Roberto

    2009-01-01

    In wireless sensor networks, more so generally than in other types of distributed systems, clock synchronization is crucial since by having this service available, several applications such as media access protocols, object tracking, or data fusion, would improve their performance. In this dissertation, we propose a set of algorithms to achieve…

  17. Thick-film acoustic emission sensors for use in structurally integrated condition-monitoring applications.

    PubMed

    Pickwell, Andrew J; Dorey, Robert A; Mba, David

    2011-09-01

    Monitoring the condition of complex engineering structures is an important aspect of modern engineering, eliminating unnecessary work and enabling planned maintenance, preventing failure. Acoustic emissions (AE) testing is one method of implementing continuous nondestructive structural health monitoring. A novel thick-film (17.6 μm) AE sensor is presented. Lead zirconate titanate thick films were fabricated using a powder/sol composite ink deposition technique and mechanically patterned to form a discrete thick-film piezoelectric AE sensor. The thick-film sensor was benchmarked against a commercial AE device and was found to exhibit comparable responses to simulated acoustic emissions.

  18. Fiber-connected position localization sensor networks

    NASA Astrophysics Data System (ADS)

    Pan, Shilong; Zhu, Dan; Fu, Jianbin; Yao, Tingfeng

    2014-11-01

    Position localization has drawn great attention due to its wide applications in radars, sonars, electronic warfare, wireless communications and so on. Photonic approaches to realize position localization can achieve high-resolution, which also provides the possibility to move the signal processing from each sensor node to the central station, thanks to the low loss, immunity to electromagnetic interference (EMI) and broad bandwidth brought by the photonic technologies. In this paper, we present a review on the recent works of position localization based on photonic technologies. A fiber-connected ultra-wideband (UWB) sensor network using optical time-division multiplexing (OTDM) is proposed to realize high-resolution localization and moving the signal processing to the central station. A 3.9-cm high spatial resolution is achieved. A wavelength-division multiplexed (WDM) fiber-connected sensor network is also demonstrated to realize location which is independent of the received signal format.

  19. Distributed Estimation, Coding, and Scheduling in Wireless Visual Sensor Networks

    ERIC Educational Resources Information Center

    Yu, Chao

    2013-01-01

    In this thesis, we consider estimation, coding, and sensor scheduling for energy efficient operation of wireless visual sensor networks (VSN), which consist of battery-powered wireless sensors with sensing (imaging), computation, and communication capabilities. The competing requirements for applications of these wireless sensor networks (WSN)…

  20. Improved fibre optic acoustic sensors for partial discharge in elastomeric insulations

    NASA Astrophysics Data System (ADS)

    Rohwetter, Philipp; Lothongkam, Chaiyaporn; Habel, Wolfgang; Heidmann, Gerd; Pepper, Daniel

    2014-05-01

    Partial discharge in elastomeric high voltage insulations is a major reason for device failure. The special challenges of the high voltage environment limit the use of conventional acoustic emission sensors. Fibre-optic sensors can cope with these challenges thanks to their optical sensing principle and the use of all-dielectric materials. In this contribution, improvements to a previously introduced design of ultrasonic fibre-optic acoustic partial discharge sensors for elastomeric insulations are presented. The improved performance of fibre-optic acoustic sensors in detecting AC partial discharge is demonstrated. Furthermore, their ability to detect low-level damage processes in elastomeric insulation under DC dielectric stress is shown to outperform the highly sensitive electrical detection method.

  1. Investigation of the thickness effect to impedance analysis results AlGaN acoustic sensor

    NASA Astrophysics Data System (ADS)

    Özen, Soner; Bilgiç, Eyüp; Gülmez, Gülay; Şenay, Volkan; Pat, Suat; Korkmaz, Şadan; Mohammadigharehbagh, Reza

    2016-03-01

    In this study, AlGaN acoustic sensors were deposited on aluminum metal substrate by thermionic vacuum arc (TVA) method, for the first time. Impedance analyses of the fabricated acoustic sensors were investigated for the determining of effect of the nano layer thickness. Thickness values are very close to each others. Fabricated sensors have been fabricated from AlGaN deposited on aluminum substrates. Gallium materials are used in many applications for optoelectronic device and semiconductor technology. Thermionic vacuum arc is the deposition technology for the variously materials and applications field. TVA production parameters and some properties of the deposited layers were investigated. TVA is the fast deposition technology for the gallium compounds and doped gallium compounds. Obtained results that AlGaN layer are very promising material for an acoustic sensor but also TVA is proper fast technology for the production.

  2. Sensor placement for municipal water networks.

    SciTech Connect

    Watson, Jean-Paul; Berry, Jonathan W.; Phillips, Cynthia Ann; Boman, Erik Gunnar; Hart, David Blaine; Carr, Robert D.; McKenna, Sean Andrew; Hart, William Eugene; Murray, Regan Elizabeth; Riesen, Lee Ann

    2010-12-01

    We consider the problem of placing a limited number of sensors in a municipal water distribution network to minimize the impact over a given suite of contamination incidents. In its simplest form, the sensor placement problem is a p-median problem that has structure extremely amenable to exact and heuristic solution methods. We describe the solution of real-world instances using integer programming or local search or a Lagrangian method. The Lagrangian method is necessary for solution of large problems on small PCs. We summarize a number of other heuristic methods for effectively addressing issues such as sensor failures, tuning sensors based on local water quality variability, and problem size/approximation quality tradeoffs. These algorithms are incorporated into the TEVA-SPOT toolkit, a software suite that the US Environmental Protection Agency has used and is using to design contamination warning systems for US municipal water systems.

  3. Intruder Activity Analysis under Unreliable Sensor Networks

    SciTech Connect

    Tae-Sic Yoo; Humberto E. Garcia

    2007-09-01

    This paper addresses the problem of counting intruder activities within a monitored domain by a sensor network. The deployed sensors are unreliable. We characterize imperfect sensors with misdetection and false-alarm probabilities. We model intruder activities with Markov Chains. A set of Hidden Markov Models (HMM) models the imperfect sensors and intruder activities to be monitored. A novel sequential change detection/isolation algorithm is developed to detect and isolate a change from an HMM representing no intruder activity to another HMM representing some intruder activities. Procedures for estimating the entry time and the trace of intruder activities are developed. A domain monitoring example is given to illustrate the presented concepts and computational procedures.

  4. Tracking a convoy of multiple targets using acoustic sensor data

    NASA Astrophysics Data System (ADS)

    Damarla, T. R.

    2003-08-01

    In this paper we present an algorithm to track a convoy of several targets in a scene using acoustic sensor array data. The tracking algorithm is based on template of the direction of arrival (DOA) angles for the leading target. Often the first target is the closest target to the sensor array and hence the loudest with good signal to noise ratio. Several steps were used to generate a template of the DOA angle for the leading target, namely, (a) the angle at the present instant should be close to the angle at the previous instant and (b) the angle at the present instant should be within error bounds of the predicted value based on the previous values. Once the template of the DOA angles of the leading target is developed, it is used to predict the DOA angle tracks of the remaining targets. In order to generate the tracks for the remaining targets, a track is established if the angles correspond to the initial track values of the first target. Second the time delay between the first track and the remaining tracks are estimated at the highest correlation points between the first track and the remaining tracks. As the vehicles move at different speeds the tracks either compress or expand depending on whether a target is moving fast or slow compared to the first target. The expansion and compression ratios are estimated and used to estimate the predicted DOA angle values of the remaining targets. Based on these predicted DOA angles of the remaining targets the DOA angles obtained from the MVDR or Incoherent MUSIC will be appropriately assigned to proper tracks. Several other rules were developed to avoid mixing the tracks. The algorithm is tested on data collected at Aberdeen Proving Ground with a convoy of 3, 4 and 5 vehicles. Some of the vehicles are tracked and some are wheeled vehicles. The tracking algorithm results are found to be good. The results will be presented at the conference and in the paper.

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

    PubMed Central

    Ramos, Alex; Filho, Raimir Holanda

    2015-01-01

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

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

    PubMed

    Ramos, Alex; Filho, Raimir Holanda

    2015-01-19

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

  7. Pulse based sensor networking using mechanical waves through metal substrates

    NASA Astrophysics Data System (ADS)

    Lorenz, S.; Dong, B.; Huo, Q.; Tomlinson, W. J.; Biswas, S.

    2013-05-01

    This paper presents a novel wireless sensor networking technique using ultrasonic signal as the carrier wave for binary data exchange. Using the properties of lamb wave propagation through metal substrates, the proposed network structure can be used for runtime transport of structural fault information to ultrasound access points. Primary applications of the proposed sensor networking technique will include conveying fault information on an aircraft wing or on a bridge to an ultrasonic access point using ultrasonic wave through the structure itself (i.e. wing or bridge). Once a fault event has been detected, a mechanical pulse is forwarded to the access node using shortest path multi-hop ultrasonic pulse routing. The advantages of mechanical waves over traditional radio transmission using pulses are the following: First, unlike radio frequency, surface acoustic waves are not detectable outside the medium, which increases the inherent security for sensitive environments in respect to tapping. Second, event detection can be represented by the injection of a single mechanical pulse at a specific temporal position, whereas radio messages usually take several bits. The contributions of this paper are: 1) Development of a transceiver for transmitting/receiving ultrasound pulses with a pulse loss rate below 2·10-5 and false positive rate with an upper bound of 2·10-4. 2) A novel one-hop distance estimation based on the properties of lamb wave propagation with an accuracy of above 80%. 3) Implementation of a wireless sensor network using mechanical wave propagation for event detection on a 2024 aluminum alloy commonly used for aircraft skin construction.

  8. Fuzzy controlled neural network for sensor fusion with adaptability to sensor failure

    NASA Astrophysics Data System (ADS)

    Chen, Judy; Kostrzewski, Andrew A.; Kim, Dai Hyun; Savant, Gajendra D.; Kim, Jeongdal; Vasiliev, Anatoly A.

    1997-10-01

    Artificial neural networks have proven to be powerful tools for sensor fusion, but they are not adaptable to sensor failure in a sensor suite. Physical Optics Corporation (POC) presents a new sensor fusion algorithm, applying fuzzy logic to give a neural network real-time adaptability to compensate for faulty sensors. Identifying data that originates from malfunctioning sensors, and excluding it from sensor fusion, allows the fuzzy neural network to achieve better results. A fuzzy logic-based functionality evaluator detects malfunctioning sensors in real time. A separate neural network is trained for each potential sensor failure situation. Since the number of possible sensor failure situations is large, the large number of neural networks is then fuzzified into a small number of fuzzy neural networks. Experimental results show the feasibility of the proposed approach -- the system correctly recognized airplane models in a computer simulation.

  9. A Network Coding Based Routing Protocol for Underwater Sensor Networks

    PubMed Central

    Wu, Huayang; Chen, Min; Guan, Xin

    2012-01-01

    Due to the particularities of the underwater environment, some negative factors will seriously interfere with data transmission rates, reliability of data communication, communication range, and network throughput and energy consumption of underwater sensor networks (UWSNs). Thus, full consideration of node energy savings, while maintaining a quick, correct and effective data transmission, extending the network life cycle are essential when routing protocols for underwater sensor networks are studied. In this paper, we have proposed a novel routing algorithm for UWSNs. To increase energy consumption efficiency and extend network lifetime, we propose a time-slot based routing algorithm (TSR).We designed a probability balanced mechanism and applied it to TSR. The theory of network coding is introduced to TSBR to meet the requirement of further reducing node energy consumption and extending network lifetime. Hence, time-slot based balanced network coding (TSBNC) comes into being. We evaluated the proposed time-slot based balancing routing algorithm and compared it with other classical underwater routing protocols. The simulation results show that the proposed protocol can reduce the probability of node conflicts, shorten the process of routing construction, balance energy consumption of each node and effectively prolong the network lifetime. PMID:22666045

  10. LONG-TERM MONITORING SENSOR NETWORK

    SciTech Connect

    Stephen P. Farrington; John W. Haas; Neal Van Wyck

    2003-10-16

    Long-term monitoring (LTM) associated with subsurface contamination sites is a key element of Long Term Stewardship and Legacy Management across the Department of Energy (DOE) complex. However, both within the DOE and elsewhere, LTM is an expensive endeavor, often exceeding the costs of the remediation phase of a clean-up project. The primary contributors to LTM costs are associated with labor. Sample collection, storage, preparation, analysis, and reporting can add a significant financial burden to project expense when extended over many years. Development of unattended, in situ monitoring networks capable of providing quantitative data satisfactory to regulatory concerns has the potential to significantly reduce LTM costs. But survival and dependable operation in a difficult environment is a common obstacle to widespread use across the DOE complex or elsewhere. Deploying almost any sensor in the subsurface for extended periods of time will expose it to chemical and microbial degradation. Over the time-scales required for in situ LTM, even the most advanced sensor systems may be rendered useless. Frequent replacement or servicing (cleaning) of sensors is expensive and labor intensive, offsetting most, if not all, of the cost savings realized with unattended, in situ sensors. To enable facile, remote monitoring of contaminants and other subsurface parameters over prolonged periods, Applied Research Associates, Inc has been working to develop an advanced LTM sensor network consisting of three key elements: (1) an anti-fouling sensor chamber that can accommodate a variety of chemical and physical measurement devices based on electrochemical, optical and other techniques; (2) two rapid, cost effective, and gentle means of emplacing sensor packages either at precise locations directly in the subsurface or in pre-existing monitoring wells; and (3) a web browser-based data acquisition and control system (WebDACS) utilizing field-networked microprocessor-controlled smart

  11. Multi Reflection of Lamb Wave Emission in an Acoustic Waveguide Sensor

    PubMed Central

    Schmitt, Martin; Olfert, Sergei; Rautenberg, Jens; Lindner, Gerhard; Henning, Bernd; Reindl, Leonhard Michael

    2013-01-01

    Recently, an acoustic waveguide sensor based on multiple mode conversion of surface acoustic waves at the solid—liquid interfaces has been introduced for the concentration measurement of binary and ternary mixtures, liquid level sensing, investigation of spatial inhomogenities or bubble detection. In this contribution the sound wave propagation within this acoustic waveguide sensor is visualized by Schlieren imaging for continuous and burst operation the first time. In the acoustic waveguide the antisymmetrical zero order Lamb wave mode is excited by a single phase transducer of 1 MHz on thin glass plates of 1 mm thickness. By contact to the investigated liquid Lamb waves propagating on the first plate emit pressure waves into the adjacent liquid, which excites Lamb waves on the second plate, what again causes pressure waves traveling inside the liquid back to the first plate and so on. The Schlieren images prove this multi reflection within the acoustic waveguide, which confirms former considerations and calculations based on the receiver signal. With this knowledge the sensor concepts with the acoustic waveguide sensor can be interpreted in a better manner. PMID:23447010

  12. IR sensors and imagers in networked operations

    NASA Astrophysics Data System (ADS)

    Breiter, Rainer; Cabanski, Wolfgang

    2005-05-01

    "Network-centric Warfare" is a common slogan describing an overall concept of networked operation of sensors, information and weapons to gain command and control superiority. Referring to IR sensors, integration and fusion of different channels like day/night or SAR images or the ability to spread image data among various users are typical requirements. Looking for concrete implementations the German Army future infantryman IdZ is an example where a group of ten soldiers build a unit with every soldier equipped with a personal digital assistant (PDA) for information display, day photo camera and a high performance thermal imager for every unit. The challenge to allow networked operation among such a unit is bringing information together and distribution over a capable network. So also AIM's thermal reconnaissance and targeting sight HuntIR which was selected for the IdZ program provides this capabilities by an optional wireless interface. Besides the global approach of Network-centric Warfare network technology can also be an interesting solution for digital image data distribution and signal processing behind the FPA replacing analog video networks or specific point to point interfaces. The resulting architecture can provide capabilities of data fusion from e.g. IR dual-band or IR multicolor sensors. AIM has participated in a German/UK collaboration program to produce a demonstrator for day/IR video distribution via Gigabit Ethernet for vehicle applications. In this study Ethernet technology was chosen for network implementation and a set of electronics was developed for capturing video data of IR and day imagers and Gigabit Ethernet video distribution. The demonstrator setup follows the requirements of current and future vehicles having a set of day and night imager cameras and a crew station with several members. Replacing the analog video path by a digital video network also makes it easy to implement embedded training by simply feeding the network with

  13. A survey of body sensor networks.

    PubMed

    Lai, Xiaochen; Liu, Quanli; Wei, Xin; Wang, Wei; Zhou, Guoqiao; Han, Guangyi

    2013-01-01

    The technology of sensor, pervasive computing, and intelligent information processing is widely used in Body Sensor Networks (BSNs), which are a branch of wireless sensor networks (WSNs). BSNs are playing an increasingly important role in the fields of medical treatment, social welfare and sports, and are changing the way humans use computers. Existing surveys have placed emphasis on the concept and architecture of BSNs, signal acquisition, context-aware sensing, and system technology, while this paper will focus on sensor, data fusion, and network communication. And we will introduce the research status of BSNs, the analysis of hotspots, and future development trends, the discussion of major challenges and technical problems facing currently. The typical research projects and practical application of BSNs are introduced as well. BSNs are progressing along the direction of multi-technology integration and intelligence. Although there are still many problems, the future of BSNs is fundamentally promising, profoundly changing the human-machine relationships and improving the quality of people's lives. PMID:23615581

  14. A survey of body sensor networks.

    PubMed

    Lai, Xiaochen; Liu, Quanli; Wei, Xin; Wang, Wei; Zhou, Guoqiao; Han, Guangyi

    2013-04-24

    The technology of sensor, pervasive computing, and intelligent information processing is widely used in Body Sensor Networks (BSNs), which are a branch of wireless sensor networks (WSNs). BSNs are playing an increasingly important role in the fields of medical treatment, social welfare and sports, and are changing the way humans use computers. Existing surveys have placed emphasis on the concept and architecture of BSNs, signal acquisition, context-aware sensing, and system technology, while this paper will focus on sensor, data fusion, and network communication. And we will introduce the research status of BSNs, the analysis of hotspots, and future development trends, the discussion of major challenges and technical problems facing currently. The typical research projects and practical application of BSNs are introduced as well. BSNs are progressing along the direction of multi-technology integration and intelligence. Although there are still many problems, the future of BSNs is fundamentally promising, profoundly changing the human-machine relationships and improving the quality of people's lives.

  15. Distributed intelligence in wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Shirgur, Vikram L.; Rao, Vittal S.

    2003-07-01

    With the advent of new wireless standards, faster microprocessors and smart sensors, it has become possible to construct wireless sensor networks with ample processing and communication capability. Our thrust in this paper is toward implementing a collaborative processing system for wireless sensor networks. A number of research groups have developed algorithms for applications such as target tracking and location, environment monitoring, and health monitoring of structures. What has been missing is a distributed sensor processing system which provides a framework for these algorithms to function. The system described here borrows heavily from the parallel processing sphere especially the Parallel Virtual Machine (PVM) system developed by ORNL. To facilitate distribution of computational resources, a new algorithm has been proposed for efficient distribution with the use of minimum system resources, in other words, determining an optimal set of nodes which can handle the distributed computation. For this purpose, we assign costs to the various parameters of interest in the network such as the node energy level, the communication energy cost/complexity and resource availability. We then arrive at a cost function by assigning suitable weights to these costs and choose only those nodes whose cost function evaluates to above a particular threshold value. Implementation of typical feature extraction algorithms such as the Discrete Fourier Transform (DFT) and the Discrete Wavelet Transform (DWT) are discussed.

  16. Serial FBG sensor network allowing overlapping spectra

    NASA Astrophysics Data System (ADS)

    Abbenseth, S.; Lochmann, S.; Ahrens, A.; Rehm, B.

    2016-05-01

    For structure or material monitoring low impact serial fiber Bragg grating (FBG) networks have attracted increasing research interest. Common sensor networks using wavelength division multiplexing (WDM) for FBG interrogation are limited in their efficiency by the spectral width of their light source, the FBG tuning range and the spectral guard bands. Overlapping spectra are strictly forbidden in this case. Applying time division multiplexing (TDM) or active resonator schemes may overcome these restrictions. However, they introduce other substantial disadvantages like signal roundtrip dependency or sophisticated control of active resonating structures. Code division multiplexing (CDM) as a means of FBG interrogation by simple autocorrelation of appropriate codes has been shown to be superior in this respect. However, it came at the cost of a second spectrometer introducing additional equalization efforts. We demonstrate a new serial FBG sensor network utilizing CDM signal processing for efficient sensor interrogation without the need of a second spectrometer and additional state of polarization (SOP) controlling components. It allows overlapping spectra even when all sensing FBGs are positioned at the same centre wavelength and it shows a high degree of insensitivity to SOP. Sequence inversed keyed (SIK) serial signal processing utilizing quasi-orthogonal balanced codes ensures simple and quick sensor interrogation with high signal-to-interference/noise ratio.

  17. A Survey of Body Sensor Networks

    PubMed Central

    Lai, Xiaochen; Liu, Quanli; Wei, Xin; Wang, Wei; Zhou, Guoqiao; Han, Guangyi

    2013-01-01

    The technology of sensor, pervasive computing, and intelligent information processing is widely used in Body Sensor Networks (BSNs), which are a branch of wireless sensor networks (WSNs). BSNs are playing an increasingly important role in the fields of medical treatment, social welfare and sports, and are changing the way humans use computers. Existing surveys have placed emphasis on the concept and architecture of BSNs, signal acquisition, context-aware sensing, and system technology, while this paper will focus on sensor, data fusion, and network communication. And we will introduce the research status of BSNs, the analysis of hotspots, and future development trends, the discussion of major challenges and technical problems facing currently. The typical research projects and practical application of BSNs are introduced as well. BSNs are progressing along the direction of multi-technology integration and intelligence. Although there are still many problems, the future of BSNs is fundamentally promising, profoundly changing the human-machine relationships and improving the quality of people's lives. PMID:23615581

  18. Sensor Network Provides Environmental Data

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The National Biocomputation Center, a joint partnership between the Stanford University School of Medicine's Department of Surgery and NASA's Ames Research Center, is the test bed for much of NASA's research in telemedicine, the remote delivery of medical care. In early 2005, researchers at the National Biocomputation Center formed a spinoff company, Intelesense Technologies, to use the telemedicine sensors to provide integrated global monitoring systems. Intelesense uses the systems to better understand how environments and people are linked, monitor and protect natural resources, predict and adapt to environmental changes, provide for sustainable development, reduce the costs and impacts of natural disasters, and provide an effective and intelligent response to such disasters. Current projects range from protecting the environment to tracking emerging infectious diseases like avian influenza (bird flu) and helping people from around the world connect and interact with each other to better understand their environment and themselves.

  19. Optimal topologies for wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Tillett, Jason C.; Yang, Shanchieh J.; Rao, Raghuveer M.; Sahin, Ferat

    2004-11-01

    Since untethered sensor nodes operate on battery, and because they must communicate through a multi-hop network, it is vital to optimally configure the transmit power of the nodes both to conserve power and optimize spatial reuse of a shared channel. Current topology control algorithms try to minimize radio power while ensuring connectivity of the network. We propose that another important metric for a sensor network topology will involve consideration of hidden nodes and asymmetric links. Minimizing the number of hidden nodes and asymmetric links at the expense of increasing the transmit power of a subset of the nodes may in fact increase the longevity of the sensor network. In this paper we explore a distributed evolutionary approach to optimizing this new metric. Inspiration from the Particle Swarm Optimization technique motivates a distributed version of the algorithm. We generate topologies with fewer hidden nodes and asymmetric links than a comparable algorithm and present some results that indicate that our topologies deliver more data and last longer.

  20. Radiation detection with distributed sensor networks

    NASA Astrophysics Data System (ADS)

    Mielke, Angela M.; Smith, Mark C.; Brennan, Sean M.; Torney, David C.; Jackson, Diana; Karlin, Josh F.; Maccabe, Arthur B.

    2005-05-01

    Given the heightened awareness and response to threats posed to national security, it is important to evaluate, and if possible, improve current measures being taken to ensure our nation"s safety. With terrorism so prevalent in our thoughts, the possible risk of nuclear attacks remains a major concern. Portal monitors are one type of technology that may be used to combat this risk. Their purpose is to detect nuclear materials and, if found, alert first responders to such a discovery. Los Alamos National Laboratory (LANL) is currently working on an alternative to these costly portal monitors through the Distributed Sensor Network (DSN) project. In collaboration with the University of New Mexico (UNM), this project aims to develop distributed networks of heterogeneous sensors with the ability to process data in-situ in order to produce real-time decisions regarding the presence of radioactive material within the network. The focus of the work described in this paper has been the evaluation of current commercial products available for application deployments, as well as the development of a sensor network in simulation to reduce key deployment issues.

  1. Dynamic Privacy Management in Pervasive Sensor Networks

    NASA Astrophysics Data System (ADS)

    Gong, Nan-Wei; Laibowitz, Mathew; Paradiso, Joseph A.

    This paper describes the design and implementation of a dynamic privacy management system aimed at enabling tangible privacy control and feedback in a pervasive sensor network. Our work began with the development of a potentially invasive sensor network (with high resolution video, audio, and motion tracking capabilities) featuring different interactive applications that created incentive for accepting this network as an extension of people's daily social space. A user study was then conducted to evaluate several privacy management approaches - an active badge system for both online and on-site control, on/off power switches for physically disabling the hardware, and touch screen input control. Results from a user study indicated that an active badge for on-site privacy control is the most preferable method among all provided options. We present a set of results that yield insight into the privacy/benefit tradeoff from various sensing capabilities in pervasive sensor networks and how privacy settings and user behavior relate in these environments.

  2. 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.

  3. Gas Main Sensor and Communications Network System

    SciTech Connect

    Hagen Schempf

    2006-05-31

    Automatika, Inc. was contracted by the Department of Energy (DOE) and with co-funding from the Northeast Gas Association (NGA), to develop an in-pipe natural gas prototype measurement and wireless communications system for assessing and monitoring distribution networks. This projected was completed in April 2006, and culminated in the installation of more than 2 dozen GasNet nodes in both low- and high-pressure cast-iron and steel mains owned by multiple utilities in the northeastern US. Utilities are currently logging data (off-line) and monitoring data in real time from single and multiple networked sensors over cellular networks and collecting data using wireless bluetooth PDA systems. The system was designed to be modular, using in-pipe sensor-wands capable of measuring, flow, pressure, temperature, water-content and vibration. Internal antennae allowed for the use of the pipe-internals as a waveguide for setting up a sensor network to collect data from multiple nodes simultaneously. Sensor nodes were designed to be installed with low- and no-blow techniques and tools. Using a multi-drop bus technique with a custom protocol, all electronics were designed to be buriable and allow for on-board data-collection (SD-card), wireless relaying and cellular network forwarding. Installation options afforded by the design included direct-burial and external polemounted variants. Power was provided by one or more batteries, direct AC-power (Class I Div.2) and solar-array. The utilities are currently in a data-collection phase and intend to use the collected (and processed) data to make capital improvement decisions, compare it to Stoner model predictions and evaluate the use of such a system for future expansion, technology-improvement and commercialization starting later in 2006.

  4. Improving the sensitivity of an interferometric fiber optic sensor for acoustic detection in rockfalls

    NASA Astrophysics Data System (ADS)

    Schenato, L.; Palmieri, L.; Autizi, E.; Galtarossa, A.; Pasuto, A.

    2013-12-01

    Being intrinsically EMI free and offering superior hostile environment operation, fiber optic sensor technology represents a valuable alternative to standard sensors technology in landslides monitoring. Here an improved design for a fiber optic sensor to be used for ultrasonic acoustic detection in rockfall monitoring is proposed. Basically, the original sensor consists of a fiber coil tightly wound on an aluminum flanged hollow mandrel that acts as the sensing arm of a Mach-Zehnder interferometer [1]. To further improve sensor sensitivity, the use of a special fiber, with polyimide coating and very large numerical aperture, has been proposed and tested. The polyimide coating, harder and thinner than standard coating, makes the fiber more sensitive to acoustic waves and increase the coupling efficiency between fiber and mandrel. At the same time, a fiber with very large numerical aperture allows for a much smaller bending radius and thus enables the design of a sensor with reduced size, or with the same external size but housing a longer fiber. Part of the research activity has been then focused toward the optimization of the shape and dimensions of the mandrel: to this aim, a large set of numerical simulations has been performed and they are here presented and discussed. The performance assessment gained with new sensors has been carried in a controlled scenario by using a block of trachyte in which the sensors have been screwed in internally threaded chemical anchors housed in holes drilled on one face of the block. Ultrasonic signals have been generated in a repeatable way by dropping a 5-mm-diameter steel ball along a steep slide. Experimental tests, carried out by firstly comparing the performance of a sensor made with special fiber with respect to the original one, have shown an increased sensitivity of almost 35 % in the detected acoustic energy. Further tests, carried out on a sensor with optimized dimensions and made with special fiber, have shown an

  5. Study on high temperature Fabry-Perot fiber acoustic sensor with temperature self-compensation

    NASA Astrophysics Data System (ADS)

    Hu, Pan; Tong, Xinglin; Zhao, Minli; Deng, Chengwei; Guo, Qian; Mao, Yan; Wang, Kun

    2015-09-01

    A Fabry-Perot (F-P) fiber acoustic sensor, which can work under high-temperature harsh environment with temperature self-compensation, is designed and prepared. A condenser was used to maintain the sensor to work in a stable temperature environment. Because of the special structure of the sensor and the function of the condenser, the cavity variation of the sensor caused by changes of external temperature from -10°C to 500°C would not exceed 8 nm. The experimental results show that the sensor has a good frequency response in a range of 1 to 5 kHz and the field experiment results show that it could be used for hydraulic decoking online monitoring by judging the acoustic frequency spectrum.

  6. 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.

  7. Achieving network level privacy in Wireless Sensor Networks.

    PubMed

    Shaikh, Riaz Ahmed; Jameel, Hassan; d'Auriol, Brian J; Lee, Heejo; Lee, Sungyoung; Song, Young-Jae

    2010-01-01

    Full network level privacy has often been categorized into four sub-categories: Identity, Route, Location and Data privacy. Achieving full network level privacy is a critical and challenging problem due to the constraints imposed by the sensor nodes (e.g., energy, memory and computation power), sensor networks (e.g., mobility and topology) and QoS issues (e.g., packet reach-ability and timeliness). In this paper, we proposed two new identity, route and location privacy algorithms and data privacy mechanism that addresses this problem. The proposed solutions provide additional trustworthiness and reliability at modest cost of memory and energy. Also, we proved that our proposed solutions provide protection against various privacy disclosure attacks, such as eavesdropping and hop-by-hop trace back attacks.

  8. Connectivity, Coverage and Placement in Wireless Sensor Networks

    PubMed Central

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

    2009-01-01

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

  9. 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

  10. New research on MEMS acoustic vector sensors used in pipeline ground markers.

    PubMed

    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°.

  11. Wireless Sensor Network Handles Image Data

    NASA Technical Reports Server (NTRS)

    2008-01-01

    To relay data from remote locations for NASA s Earth sciences research, Goddard Space Flight Center contributed to the development of "microservers" (wireless sensor network nodes), which are now used commercially as a quick and affordable means to capture and distribute geographical information, including rich sets of aerial and street-level imagery. NASA began this work out of a necessity for real-time recovery of remote sensor data. These microservers work much like a wireless office network, relaying information between devices. The key difference, however, is that instead of linking workstations within one office, the interconnected microservers operate miles away from one another. This attribute traces back to the technology s original use: The microservers were originally designed for seismology on remote glaciers and ice streams in Alaska, Greenland, and Antarctica-acquiring, storing, and relaying data wirelessly between ground sensors. The microservers boast three key attributes. First, a researcher in the field can establish a "managed network" of microservers and rapidly see the data streams (recovered wirelessly) on a field computer. This rapid feedback permits the researcher to reconfigure the network for different purposes over the course of a field campaign. Second, through careful power management, the microservers can dwell unsupervised in the field for up to 2 years, collecting tremendous amounts of data at a research location. The third attribute is the exciting potential to deploy a microserver network that works in synchrony with robotic explorers (e.g., providing ground truth validation for satellites, supporting rovers as they traverse the local environment). Managed networks of remote microservers that relay data unsupervised for up to 2 years can drastically reduce the costs of field instrumentation and data rec

  12. Tritium-powered radiation sensor network

    NASA Astrophysics Data System (ADS)

    Litz, Marc S.; Russo, Johnny A.; Katsis, Dimos

    2016-05-01

    Isotope power supplies offer long-lived (100 years using 63Ni), low-power energy sources, enabling sensors or communications nodes for the lifetime of infrastructure. A tritium beta-source (12.5-year half-life) encapsulated in a phosphor-lined vial couples directly to a photovoltaic (PV) to generate a trickle current into an electrical load. An inexpensive design is described using commercial-of-the-shelf (COTS) components that generate 100 μWe for nextgeneration compact electronics/sensors. A matched radiation sensor has been built for long-duration missions utilizing microprocessor-controlled sleep modes, low-power electronic components, and a passive interrupt driven environmental wake-up. The low-power early-warning radiation detector network and isotope power source enables no-maintenance mission lifetimes.

  13. Communal Sensor Network for Adaptive Noise Reduction in Aircraft Engine Nacelles

    NASA Technical Reports Server (NTRS)

    Jones, Kennie H.; Nark, Douglas M.; Jones, Michael G.

    2011-01-01

    Emergent behavior, a subject of much research in biology, sociology, and economics, is a foundational element of Complex Systems Science and is apropos in the design of sensor network systems. To demonstrate engineering for emergent behavior, a novel approach in the design of a sensor/actuator network is presented maintaining optimal noise attenuation as an adaptation to changing acoustic conditions. Rather than use the conventional approach where sensors are managed by a central controller, this new paradigm uses a biomimetic model where sensor/actuators cooperate as a community of autonomous organisms, sharing with neighbors to control impedance based on local information. From the combination of all individual actions, an optimal attenuation emerges for the global system.

  14. Graph-based sensor fusion for classification of transient acoustic signals.

    PubMed

    Srinivas, Umamahesh; Nasrabadi, Nasser M; Monga, Vishal

    2015-03-01

    Advances in acoustic sensing have enabled the simultaneous acquisition of multiple measurements of the same physical event via co-located acoustic sensors. We exploit the inherent correlation among such multiple measurements for acoustic signal classification, to identify the launch/impact of munition (i.e., rockets, mortars). Specifically, we propose a probabilistic graphical model framework that can explicitly learn the class conditional correlations between the cepstral features extracted from these different measurements. Additionally, we employ symbolic dynamic filtering-based features, which offer improvements over the traditional cepstral features in terms of robustness to signal distortions. Experiments on real acoustic data sets show that our proposed algorithm outperforms conventional classifiers as well as the recently proposed joint sparsity models for multisensor acoustic classification. Additionally our proposed algorithm is less sensitive to insufficiency in training samples compared to competing approaches. PMID:25014986

  15. SITRUS: Semantic Infrastructure for Wireless Sensor Networks.

    PubMed

    Bispo, Kalil A; Rosa, Nelson S; Cunha, Paulo R F

    2015-01-01

    Wireless sensor networks (WSNs) are made up of nodes with limited resources, such as processing, bandwidth, memory and, most importantly, energy. For this reason, it is essential that WSNs always work to reduce the power consumption as much as possible in order to maximize its lifetime. In this context, this paper presents SITRUS (semantic infrastructure for wireless sensor networks), which aims to reduce the power consumption of WSN nodes using ontologies. SITRUS consists of two major parts: a message-oriented middleware responsible for both an oriented message communication service and a reconfiguration service; and a semantic information processing module whose purpose is to generate a semantic database that provides the basis to decide whether a WSN node needs to be reconfigurated or not. In order to evaluate the proposed solution, we carried out an experimental evaluation to assess the power consumption and memory usage of WSN applications built atop SITRUS.

  16. SITRUS: Semantic Infrastructure for Wireless Sensor Networks.

    PubMed

    Bispo, Kalil A; Rosa, Nelson S; Cunha, Paulo R F

    2015-01-01

    Wireless sensor networks (WSNs) are made up of nodes with limited resources, such as processing, bandwidth, memory and, most importantly, energy. For this reason, it is essential that WSNs always work to reduce the power consumption as much as possible in order to maximize its lifetime. In this context, this paper presents SITRUS (semantic infrastructure for wireless sensor networks), which aims to reduce the power consumption of WSN nodes using ontologies. SITRUS consists of two major parts: a message-oriented middleware responsible for both an oriented message communication service and a reconfiguration service; and a semantic information processing module whose purpose is to generate a semantic database that provides the basis to decide whether a WSN node needs to be reconfigurated or not. In order to evaluate the proposed solution, we carried out an experimental evaluation to assess the power consumption and memory usage of WSN applications built atop SITRUS. PMID:26528974

  17. SITRUS: Semantic Infrastructure for Wireless Sensor Networks

    PubMed Central

    Bispo, Kalil A.; Rosa, Nelson S.; Cunha, Paulo R. F.

    2015-01-01

    Wireless sensor networks (WSNs) are made up of nodes with limited resources, such as processing, bandwidth, memory and, most importantly, energy. For this reason, it is essential that WSNs always work to reduce the power consumption as much as possible in order to maximize its lifetime. In this context, this paper presents SITRUS (semantic infrastructure for wireless sensor networks), which aims to reduce the power consumption of WSN nodes using ontologies. SITRUS consists of two major parts: a message-oriented middleware responsible for both an oriented message communication service and a reconfiguration service; and a semantic information processing module whose purpose is to generate a semantic database that provides the basis to decide whether a WSN node needs to be reconfigurated or not. In order to evaluate the proposed solution, we carried out an experimental evaluation to assess the power consumption and memory usage of WSN applications built atop SITRUS. PMID:26528974

  18. Modal structural acoustic sensing with minimum number of optimally placed piezoelectric sensors

    NASA Astrophysics Data System (ADS)

    Loghmani, Ali; Danesh, Mohammad; Keshmiri, Mehdi

    2016-02-01

    Structural acoustic sensing is a method of obtaining radiated sound pressure from a vibrating structure using vibration information. Structural acoustic sensing is used in active structural acoustic control for attenuating the sound radiated from a structure. In this paper, a new approach called Modal Structural Acoustic Sensing (MSAS) is proposed for estimating the pressure radiated from a vibrating cylindrical shell using piezoelectric sensors. The motion equations of a cylindrical shell in conjunction with piezoelectric patches are derived based on the Donnel-Mushtari shell theory. The locations of the piezoelectric sensors are optimized by the Genetic Algorithm based on maximizing the observability gramian matrix. The Kirchhoff-Helmholtz integral is used for estimating the sound pressure radiated from the cylindrical shell. Numerical simulations are performed to demonstrate the advantages of the proposed approach in comparison with previous methods such as discrete structural acoustic sensing and distributed modal sensors. Results show that the MSAS can increase the estimation accuracy and decrease the controller dimensionality and the number of required sensors.

  19. Transduction mechanism of acoustic-wave based chemical and biochemical sensors

    NASA Astrophysics Data System (ADS)

    Lucklum, Ralf; Hauptmann, Peter

    2003-11-01

    Acoustic-wave-based sensors are commonly known as mass-sensitive devices. However, acoustic chemical and biochemical sensors also face so-called non-gravimetric effects, especially if they work in a liquid environment. The one-dimensional transmission-line model (TLM) is a powerful tool, which considers the influence of geometric and material properties on the sensor transduction mechanism, most importantly the influence of viscoelastic phenomena. This paper demonstrates the concept of modelling acoustic microsensors on quartz crystal resonators. Particular attention is paid to special cases which allow for simplifications or specific solutions of the TLM, like the acoustic load concept (ALC), the BVD model or the Sauerbrey equation. Deviations from the one-dimensional assumption of the TLM are suspected to significantly contribute to the acoustic sensor response in biosystems. We therefore introduce a generalization of the ALC to get access to two- or three-dimensional effects, which are up to now not considered in the TLM. As examples, signatures of interfacial phenomena or non-uniform films are discussed.

  20. Acoustic emission from magnetic flux tubes in the solar network

    NASA Astrophysics Data System (ADS)

    Vigeesh, G.; Hasan, S. S.

    2013-06-01

    We present the results of three-dimensional numerical simulations to investigate the excitation of waves in the magnetic network of the Sun due to footpoint motions of a magnetic flux tube. We consider motions that typically mimic granular buffeting and vortex flows and implement them as driving motions at the base of the flux tube. The driving motions generates various MHD modes within the flux tube and acoustic waves in the ambient medium. The response of the upper atmosphere to the underlying photospheric motion and the role of the flux tube in channeling the waves is investigated. We compute the acoustic energy flux in the various wave modes across different boundary layers defined by the plasma and magnetic field parameters and examine the observational implications for chromospheric and coronal heating.

  1. The Biological Sensor for Detection of Bacterial Cells in Liquid Phase Based on Plate Acoustic Wave

    NASA Astrophysics Data System (ADS)

    Borodina, Irina; Zaitsev, Boris; Shikhabudinov, Alexander; Guliy, Olga; Ignatov, Oleg; Teplykh, Andrey

    The interactions "bacterial cells - bacteriophages", "bacterial cells - antibodies" and "bacterial cells - mini- antibodies" directly in liquid phase were experimentally investigated with a help of acoustic sensor. The acoustic sensor under study represents two-channel delay line based on the plate of Y-X lithium niobate. One channel of delay line was electrically shorted, the second channel was electrically open. The liquid container was glued on plate surface between transducers of delay line. The dependencies of the change in phase and insertion loss on concentration of bacteriophages, antibodies, and mini- antibodies were obtained for both channels of delay line.

  2. Hierarchical sensor network architecture for stationary smart node supervision

    NASA Astrophysics Data System (ADS)

    Jin, Ming-Hui; Wu, Wen-Jong; Chen, Chun-Kuang; Chen, Yih-Fan; Wen, Chih-Min; Kao, Cheng-Yan; Yu, Shih-An; Lin, Yun-Han; Huang, Jhen-Gang; Rao, Herman; Hsu, Ching-Hsiang; Lee, Chih-Kung

    2004-07-01

    Most wireless sensor networks base their design on an ad hoc (multi-hop) network technology that focus on organizing and maintaining a network formed by a group of moving objects with a communication device in an area with no fixed base stations or access points. Although ad hoc network technologies are capable of constructing a sensor network, the design and implementation of sensor networks for monitoring stationary nodes such as construction sites and nature-disaster-prone areas can be furthered simplified to reduce power consumption and overhead. Based on the nature of immobile nodes, a hierarchical sensor network architecture and its associated communication protocols are proposed in this paper. In this proposed architecture, most elements in the sensor network are designed to be equipped with no functions for message forwarding or channel scheduling. The local control center uses a centralized communication protocol to communicate with each sensor node. The local control center can also use ad hoc network technology to relay the data between each of the sensors. This approach not only minimizes the complexity of the sensor nodes implemented but also significantly reduces the cost, size and power consumption of each sensor node. In addition, the benefit of using ad-hoc network technology is that the local controller retains its routing capabilities. Therefore, power efficiency and communication reliability can be both achieved and maximized by this type of hierarchical sensor network.

  3. Measurement of Plasma Clotting Using Shear Horizontal Surface Acoustic Wave Sensor

    NASA Astrophysics Data System (ADS)

    Nagayama, Tatsuya; Kondoh, Jun; Oonishi, Tomoko; Hosokawa, Kazuya

    2013-07-01

    The monitoring of blood coagulation is important during operation. In this study, a shear horizontal surface acoustic wave (SH-SAW) sensor is applied to monitor plasma clotting. An SH-SAW sensor with a metallized surface for mechanical perturbation detection can detect plasma clotting. As plasma clotting is a gel formation reaction, the SH-SAW sensor detects viscoelastic property changes. On the other hand, an SH-SAW sensor with a free surface for electrical perturbation detection detects only the liquid mixing effect. No electrical property changes due to plasma clotting are obtained using this sensor. A planar electrochemical sensor is also used to monitor plasma clotting. In impedance spectral analysis, plasma clotting is measured. However, in the measurement of time responses, no differences between clotting and nonclotting are obtained. Therefore, the SH-SAW sensor is useful for monitoring plasma clotting.

  4. Acoustic intensity methods and their applications to vector sensor use and design

    NASA Astrophysics Data System (ADS)

    Naluai, Nathan Kahikina

    Applications of acoustic intensity processing methods to vector sensor output signals are investigated for three specific cases: acoustic intensity scattering, spatial correlations of intensities, and conceptual design of a high frequency inertial vector sensor with a novel suspension. An overview of intensity processing is presented and the concept of a complex intensity is illustrated. Measurement techniques for determining the complex intensity spectra from the signals received by a standard acoustic vector sensor are demonstrated. Acoustic intensity processing of signals from SSQ-53D sonobuoys is used to enhance the detection of submerged bodies in bi-static sonar applications. Deep water experiments conducted at Lake Pend Oreille in northern Idaho are described. A submerged body is located between a source and a number of SSQ-53D sonobuoy receivers. Scalar pressure measurements change by less than 0.5 dB when the scattering body is inserted in the field. The phase of the orthogonal intensity component shows repeatable and strong variations of nearly 55°. The classical solution for the spatial correlation of the pressure field is presented. The derivation techniques are expanded to derive previously unsolved analytic forms for the spatial correlations of separated intensity field components based on combinations of the solutions for various pressure and velocity components. Experimental validation of these correlation solutions are performed computationally and in an underwater environment. The computational experiments are designed to test highly controlled variations to the idealized case (e.g. sound field content, transducer phasing issues, additive output noise, etc.) Additional verification is provided from physical tests measuring the correlations between a pair of acoustic vector sensors in a large reverberant tank which is excited acoustically with broadband noise. The results successfully corroborate the derivation methods for correlations of

  5. EFPC: An Environmentally Friendly Power Control Scheme for Underwater Sensor Networks.

    PubMed

    Yang, Qiuling; Su, Yishan; Jin, Zhigang; Yao, Guidan

    2015-01-01

    In oceans, the limited acoustic spectrum resource is heavily shared by marine mammals and manmade systems including underwater sensor networks. In order to limit the negative impact of acoustic signal on marine mammals, we propose an environmentally friendly power control (EFPC) scheme for underwater sensor networks. EFPC allocates transmission power of sensor nodes with a consideration of the existence of marine mammals. By applying a Nash Equilibrium based utility function with a set of limitations to optimize transmission power, the proposed power control algorithm can conduct parallel transmissions to improve the network's goodput, while avoiding interference with marine mammals. Additionally, to localize marine mammals, which is a prerequisite of EFPC, we propose a novel passive hyperboloid localization algorithm (PHLA). PHLA passively localize marine mammals with the help of the acoustic characteristic of these targets. Simulation results show that PHLA can localize most of the target with a relatively small localization error and EFPC can achieve a close goodput performance compared with an existing power control algorithm while avoiding interfering with marine mammals.

  6. Wireless sensor network for monitoring soil moisture and weather conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wireless sensor network (WSN) was developed and deployed in three fields to monitor soil water status and collect weather data for irrigation scheduling. The WSN consists of soil-water sensors, weather sensors, wireless data loggers, and a wireless modem. Soil-water sensors were installed at three...

  7. Contactless Biometrics in Wireless Sensor Network: A Survey

    NASA Astrophysics Data System (ADS)

    Razzak, Muhammad Imran; Khan, Muhammad Khurram; Alghathbar, Khaled

    Security can be enhanced through wireless sensor network using contactless biometrics and it remains a challenging and demanding task due to several limitations of wireless sensor network. Network life time is very less if it involves image processing task due to heavy energy required for image processing and image communication. Contactless biometrics such as face recognition is most suitable and applicable for wireless sensor network. Distributed face recognition in WSN not only help to reduce the communication overload but it also increase the node life time by distributing the work load on the nodes. This paper presents state-of-art of biometrics in wireless sensor network.

  8. Time synchronization in ad-hoc wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Sharma, Nishant

    2013-06-01

    Advances in micro-electronics and developments in the various technologies have given birth to this era of wireless sensor networks. A sensor network is the one which provides information about the surrounding environment by sensing it and clock synchronization in wireless sensor networks plays a vital role to maintain the integrity of entire network. In this paper two major low energy consumption clock synchronization algorithms, Reference Broadcast Synchronization (RBS) and Timing-Sync Protocol for Sensor Networks (TPSN) are simulated, which result in high level of accuracy, reliability, handles substantially greater node densities, supports mobility, and hence perform well under all possible conditions.

  9. A novel compound chaotic block cipher for wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Tong, Xiao-Jun; Wang, Zhu; Liu, Yang; Zhang, Miao; Xu, Lianjie

    2015-05-01

    The nodes of wireless sensor network (WSN) have limited calculation and communication ability. Traditional encryption algorithms need large amounts of resources, so they cannot be applied to the wireless sensor network. To solve this problem, this paper proposes a block cipher algorithm for wireless sensor network based on compound chaotic map. The algorithm adopts Feistel network and constructs a Cubic function including discretized chaotic map, and its key is generated by the compound chaotic sequence. Security and performance tests show that the algorithm has high security and efficiency, low resource depletion. So the novel chaotic algorithm is suitable for the wireless sensor networks.

  10. Acoustic Detection Of Loose Particles In Pressure Sensors

    NASA Technical Reports Server (NTRS)

    Kwok, Lloyd C.

    1995-01-01

    Particle-impact-noise-detector (PIND) apparatus used in conjunction with computer program analyzing output of apparatus to detect extraneous particles trapped in pressure sensors. PIND tester essentially shaker equipped with microphone measuring noise in pressure sensor or other object being shaken. Shaker applies controlled vibration. Output of microphone recorded and expressed in terms of voltage, yielding history of noise subsequently processed by computer program. Data taken at sampling rate sufficiently high to enable identification of all impacts of particles on sensor diaphragm and on inner surfaces of sensor cavities.

  11. A surface-acoustic-wave-based cantilever bio-sensor.

    PubMed

    De Simoni, Giorgio; Signore, Giovanni; Agostini, Matteo; Beltram, Fabio; Piazza, Vincenzo

    2015-06-15

    A scalable surface-acoustic-wave- (SAW-) based cantilevered device for portable bio-chemical sensing applications is presented. Even in the current, proof-of-principle implementation this architecture is shown to outperform commercial quartz-crystal microbalances in terms of sensitivity. Adhesion of analytes on a functionalized surface of the cantilever shifts the resonant frequency of a SAW-generating transducer due to the stress-induced variation of the speed of surface acoustic modes. We discuss the relevance of this approach for diagnostics applications based on miniaturized devices.

  12. Surface acoustic wave/silicon monolithic sensor/processor

    NASA Technical Reports Server (NTRS)

    Kowel, S. T.; Kornreich, P. G.; Nouhi, A.; Kilmer, R.; Fathimulla, M. A.; Mehter, E.

    1983-01-01

    A new technique for sputter deposition of piezoelectric zinc oxide (ZnO) is described. An argon-ion milling system was converted to sputter zinc oxide films in an oxygen atmosphere using a pure zinc oxide target. Piezoelectric films were grown on silicon dioxide and silicon dioxide overlayed with gold. The sputtered films were evaluated using surface acoustic wave measurements, X-ray diffraction, scanning electron microscopy, Auger electron spectroscopy, and resistivity measurements. The effect of the sputtering conditions on the film quality and the result of post-deposition annealing are discussed. The application of these films to the generation of surface acoustic waves is also discussed.

  13. Mobile Networked Sensors for Environmental Observatories

    NASA Astrophysics Data System (ADS)

    Kaiser, W. J.

    2005-12-01

    The development of the first embedded networked sensing (ENS) systems has been rapidly followed by their successful deployment for investigations in environments ranging from forest ecosystems, to rivers and lakes, and to subsurface soil observations. As ENS systems have been deployed, many technology challenges have been successfully addressed. For example, the requirements for local and remote data access and long operating life have been encountered and solved with a novel hierarchical network architecture and unique, low power platforms. This presentation will describe this progress and also the development and applications of a new ENS system addressing the most current challenges: A robotic ENS platform providing precise, reliable, and sustained observation capability with diverse sensing capabilities that may adapt to environmental dynamics. In the development of methods for autonomous observation by networked sensors, many applications have emerged requiring spatially and temporally intensive data sampling. Examples include the mapping of forest understory solar radiation, autonomous acquisition of imaging for plant phenology, and mapping of contaminant concentration in aquatic systems. Common to these applications is the need to actively and continuously configure the location and orientation of sensors for high fidelity mapping of the spatial distribution of phenomena. To address this primary environmental observation need, a new sensing platform, Networked Infomechanical Systems (NIMS) has been developed. NIMS relies on deployed aerial infrastructure (for example, cable suspension systems) in the natural environment to permit robotic devices to precisely and reliably move or remain stationary as required at elevations that may lie directly in or above the forest canopy or within a river or stream. NIMS systems are suspended to allow devices to translate a sensor node horizontally, and also to raise and lower devices. Examples of sensors that are now

  14. Bio-Inspired Miniature Direction Finding Acoustic Sensor

    PubMed Central

    Wilmott, Daniel; Alves, Fabio; Karunasiri, Gamani

    2016-01-01

    A narrowband MEMS direction finding sensor has been developed based on the mechanically coupled ears of the Ormia Ochracea fly. The sensor consists of two wings coupled at the middle and attached to a substrate using two legs. The sensor operates at its bending resonance frequency and has cosine directional characteristics similar to that of a pressure gradient microphone. Thus, the directional response of the sensor is symmetric about the normal axis making the determination of the direction ambiguous. To overcome this shortcoming two sensors were assembled with a canted angle similar to that employed in radar bearing locators. The outputs of two sensors were processed together allowing direction finding with no requirement of knowing the incident sound pressure level. At the bending resonant frequency of the sensors (1.69 kHz) an output voltage of about 25 V/Pa was measured. The angle uncertainty of the bearing of sound ranged from less than 0.3° close to the normal axis (0°) to 3.4° at the limits of coverage (±60°) based on the 30° canted angle used. These findings indicate the great potential to use dual MEMS direction finding sensor assemblies to locate sound sources with high accuracy. PMID:27440657

  15. Bio-Inspired Miniature Direction Finding Acoustic Sensor

    NASA Astrophysics Data System (ADS)

    Wilmott, Daniel; Alves, Fabio; Karunasiri, Gamani

    2016-07-01

    A narrowband MEMS direction finding sensor has been developed based on the mechanically coupled ears of the Ormia Ochracea fly. The sensor consists of two wings coupled at the middle and attached to a substrate using two legs. The sensor operates at its bending resonance frequency and has cosine directional characteristics similar to that of a pressure gradient microphone. Thus, the directional response of the sensor is symmetric about the normal axis making the determination of the direction ambiguous. To overcome this shortcoming two sensors were assembled with a canted angle similar to that employed in radar bearing locators. The outputs of two sensors were processed together allowing direction finding with no requirement of knowing the incident sound pressure level. At the bending resonant frequency of the sensors (1.69 kHz) an output voltage of about 25 V/Pa was measured. The angle uncertainty of the bearing of sound ranged from less than 0.3° close to the normal axis (0°) to 3.4° at the limits of coverage (±60°) based on the 30° canted angle used. These findings indicate the great potential to use dual MEMS direction finding sensor assemblies to locate sound sources with high accuracy.

  16. Bio-Inspired Miniature Direction Finding Acoustic Sensor.

    PubMed

    Wilmott, Daniel; Alves, Fabio; Karunasiri, Gamani

    2016-01-01

    A narrowband MEMS direction finding sensor has been developed based on the mechanically coupled ears of the Ormia Ochracea fly. The sensor consists of two wings coupled at the middle and attached to a substrate using two legs. The sensor operates at its bending resonance frequency and has cosine directional characteristics similar to that of a pressure gradient microphone. Thus, the directional response of the sensor is symmetric about the normal axis making the determination of the direction ambiguous. To overcome this shortcoming two sensors were assembled with a canted angle similar to that employed in radar bearing locators. The outputs of two sensors were processed together allowing direction finding with no requirement of knowing the incident sound pressure level. At the bending resonant frequency of the sensors (1.69 kHz) an output voltage of about 25 V/Pa was measured. The angle uncertainty of the bearing of sound ranged from less than 0.3° close to the normal axis (0°) to 3.4° at the limits of coverage (±60°) based on the 30° canted angle used. These findings indicate the great potential to use dual MEMS direction finding sensor assemblies to locate sound sources with high accuracy. PMID:27440657

  17. Laboratory comparisons of acoustic and optical sensors for microbubble measurement

    NASA Technical Reports Server (NTRS)

    Su, Ming Yang; Todoroff, Douglas; Cartmill, John

    1994-01-01

    This paper presents the results of a recent comparison between three microbubble size spectrum measurement systems. These systems are the light-scattering bubble counter, the photographic bubble-imaging system, and the acoustic resonator array. Good agreement was formed among these three systems over the bubble size range appropriate for each system.

  18. Job-Oriented Basic Skills (JOBS) Program for the Acoustic Sensor Operations Strand.

    ERIC Educational Resources Information Center

    U'Ren, Paula Kabance; Baker, Meryl S.

    An effort was undertaken to develop a job-oriented basic skills curriculum appropriate for the acoustic sensor operations area, which includes members of four ratings: ocean systems technician, aviation antisubmarine warfare operator, sonar technician (surface), and sonar technician (submarine). Analysis of the job duties of the four ratings…

  19. Development of a standing wave apparatus for calibrating acoustic vector sensors and hydrophones.

    PubMed

    Lenhart, Richard D; Sagers, Jason D; Wilson, Preston S

    2016-01-01

    An apparatus was developed to calibrate acoustic hydrophones and vector sensors between 25 and 2000 Hz. A standing wave field is established inside a vertically oriented, water-filled, elastic-walled waveguide by a piston velocity source at the bottom and a pressure-release boundary condition at the air/water interface. A computer-controlled linear positioning system allows a device under test to be precisely located in the water column while the acoustic response is measured. Some of the challenges of calibrating hydrophones and vector sensors in such an apparatus are discussed, including designing the waveguide to mitigate dispersion, understanding the impact of waveguide structural resonances on the acoustic field, and developing algorithms to post-process calibration measurement data performed in a standing wave field. Data from waveguide characterization experiments and calibration measurements are presented and calibration uncertainty is reported. PMID:26827015

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

    PubMed

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

    2013-08-22

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

  1. Multipath routing in wireless sensor networks: survey and research challenges.

    PubMed

    Radi, Marjan; Dezfouli, Behnam; Abu Bakar, Kamalrulnizam; Lee, Malrey

    2012-01-01

    A wireless sensor network is a large collection of sensor nodes with limited power supply and constrained computational capability. Due to the restricted communication range and high density of sensor nodes, packet forwarding in sensor networks is usually performed through multi-hop data transmission. Therefore, routing in wireless sensor networks has been considered an important field of research over the past decade. Nowadays, multipath routing approach is widely used in wireless sensor networks to improve network performance through efficient utilization of available network resources. Accordingly, the main aim of this survey is to present the concept of the multipath routing approach and its fundamental challenges, as well as the basic motivations for utilizing this technique in wireless sensor networks. In addition, we present a comprehensive taxonomy on the existing multipath routing protocols, which are especially designed for wireless sensor networks. We highlight the primary motivation behind the development of each protocol category and explain the operation of different protocols in detail, with emphasis on their advantages and disadvantages. Furthermore, this paper compares and summarizes the state-of-the-art multipath routing techniques from the network application point of view. Finally, we identify open issues for further research in the development of multipath routing protocols for wireless sensor networks.

  2. Environmental Sensor Networks: A revolution in the earth system science?

    NASA Astrophysics Data System (ADS)

    Hart, Jane K.; Martinez, Kirk

    2006-10-01

    Environmental Sensor Networks (ESNs) facilitate the study of fundamental processes and the development of hazard response systems. They have evolved from passive logging systems that require manual downloading, into 'intelligent' sensor networks that comprise a network of automatic sensor nodes and communications systems which actively communicate their data to a Sensor Network Server (SNS) where these data can be integrated with other environmental datasets. The sensor nodes can be fixed or mobile and range in scale appropriate to the environment being sensed. ESNs range in scale and function and we have reviewed over 50 representative examples. Large Scale Single Function Networks tend to use large single purpose nodes to cover a wide geographical area. Localised Multifunction Sensor Networks typically monitor a small area in more detail, often with wireless ad-hoc systems. Biosensor Networks use emerging biotechnologies to monitor environmental processes as well as developing proxies for immediate use. In the future, sensor networks will integrate these three elements ( Heterogeneous Sensor Networks). The communications system and data storage and integration (cyberinfrastructure) aspects of ESNs are discussed, along with current challenges which need to be addressed. We argue that Environmental Sensor Networks will become a standard research tool for future Earth System and Environmental Science. Not only do they provide a 'virtual' connection with the environment, they allow new field and conceptual approaches to the study of environmental processes to be developed. We suggest that although technological advances have facilitated these changes, it is vital that Earth Systems and Environmental Scientists utilise them.

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

    PubMed Central

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

    2013-01-01

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

  4. Multipath Routing in Wireless Sensor Networks: Survey and Research Challenges

    PubMed Central

    Radi, Marjan; Dezfouli, Behnam; Bakar, Kamalrulnizam Abu; Lee, Malrey

    2012-01-01

    A wireless sensor network is a large collection of sensor nodes with limited power supply and constrained computational capability. Due to the restricted communication range and high density of sensor nodes, packet forwarding in sensor networks is usually performed through multi-hop data transmission. Therefore, routing in wireless sensor networks has been considered an important field of research over the past decade. Nowadays, multipath routing approach is widely used in wireless sensor networks to improve network performance through efficient utilization of available network resources. Accordingly, the main aim of this survey is to present the concept of the multipath routing approach and its fundamental challenges, as well as the basic motivations for utilizing this technique in wireless sensor networks. In addition, we present a comprehensive taxonomy on the existing multipath routing protocols, which are especially designed for wireless sensor networks. We highlight the primary motivation behind the development of each protocol category and explain the operation of different protocols in detail, with emphasis on their advantages and disadvantages. Furthermore, this paper compares and summarizes the state-of-the-art multipath routing techniques from the network application point of view. Finally, we identify open issues for further research in the development of multipath routing protocols for wireless sensor networks. PMID:22368490

  5. A supervisory control policy over an acoustic communication network

    NASA Astrophysics Data System (ADS)

    Farhadi, Alireza; Dumon, Jonathan; Canudas-de-Wit, Carlos

    2015-05-01

    This paper presents a supervisory multi-agent control policy over an acoustic communication network subject to imperfections (packet dropout and transmission delay) for localisation of an underwater flow source (e.g., source of chemical pollution, fresh water, etc.) with an unknown location at the bottom of the ocean. A two-loop control policy combined with a coding strategy for reliable communication is presented to perform the above task. A simulator is developed and used to evaluate the trade-offs between quality of communication, transmission delay and control for a fleet of autonomous underwater vehicles supervised over a noisy acoustic communication network by an autonomous surface vessel. It is illustrated that without compensation of the effects of severe random packet dropout, localisation of an unknown underwater flow source is not possible for the condition simulated just by implementing a two-loop control policy. But a two-loop control policy combined with a strategy for reliable communication locates the unknown location of flow source.

  6. Neural network based analysis for chemical sensor arrays

    SciTech Connect

    Hashem, S.; Keller, P.E.; Kouzes, R.T.; Kangas, L.J.

    1995-04-01

    Compact, portable systems capable of quickly identifying contaminants in the field are of great importance when monitoring the environment. In this paper, we examine the effectiveness of using artificial neural networks for real-time data analysis of a sensor array. Analyzing the sensor data in parallel may allow for rapid identification of contaminants in the field without requiring highly selective individual sensors. We use a prototype sensor array which consists of nine tin-oxide Taguchi-type sensors, a temperature sensor, and a humidity sensor. We illustrate that by using neural network based analysis of the sensor data, the selectivity of the sensor array may be significantly improved, especially when some (or all) the sensors are not highly selective.

  7. Fluid loading effects for acoustical sensors in the atmospheres of Mars, Venus, Titan, and Jupiter.

    PubMed

    Leighton, T G

    2009-05-01

    This paper shows that corrections for fluid loading must be undertaken to Earth-based calibrations for planetary probe sensors, which rely on accurate and precise predictions of mechanical vibrations. These sensors include acoustical instrumentation, and sensors for the mass change resulting from species accumulation upon oscillating plates. Some published designs are particularly susceptible (an example leading to around an octave error in the frequency calibration for Venus is shown). Because such corrections have not previously been raised, and would be almost impossible to incorporate into drop tests of probes, this paper demonstrates the surprising results of applying well-established formulations. PMID:19425625

  8. LinkMind: link optimization in swarming mobile sensor networks.

    PubMed

    Ngo, Trung Dung

    2011-01-01

    A swarming mobile sensor network is comprised of a swarm of wirelessly connected mobile robots equipped with various sensors. Such a network can be applied in an uncertain environment for services such as cooperative navigation and exploration, object identification and information gathering. One of the most advantageous properties of the swarming wireless sensor network is that mobile nodes can work cooperatively to organize an ad-hoc network and optimize the network link capacity to maximize the transmission of gathered data from a source to a target. This paper describes a new method of link optimization of swarming mobile sensor networks. The new method is based on combination of the artificial potential force guaranteeing connectivities of the mobile sensor nodes and the max-flow min-cut theorem of graph theory ensuring optimization of the network link capacity. The developed algorithm is demonstrated and evaluated in simulation. PMID:22164070

  9. LinkMind: Link Optimization in Swarming Mobile Sensor Networks

    PubMed Central

    Ngo, Trung Dung

    2011-01-01

    A swarming mobile sensor network is comprised of a swarm of wirelessly connected mobile robots equipped with various sensors. Such a network can be applied in an uncertain environment for services such as cooperative navigation and exploration, object identification and information gathering. One of the most advantageous properties of the swarming wireless sensor network is that mobile nodes can work cooperatively to organize an ad-hoc network and optimize the network link capacity to maximize the transmission of gathered data from a source to a target. This paper describes a new method of link optimization of swarming mobile sensor networks. The new method is based on combination of the artificial potential force guaranteeing connectivities of the mobile sensor nodes and the max-flow min-cut theorem of graph theory ensuring optimization of the network link capacity. The developed algorithm is demonstrated and evaluated in simulation. PMID:22164070

  10. LinkMind: link optimization in swarming mobile sensor networks.

    PubMed

    Ngo, Trung Dung

    2011-01-01

    A swarming mobile sensor network is comprised of a swarm of wirelessly connected mobile robots equipped with various sensors. Such a network can be applied in an uncertain environment for services such as cooperative navigation and exploration, object identification and information gathering. One of the most advantageous properties of the swarming wireless sensor network is that mobile nodes can work cooperatively to organize an ad-hoc network and optimize the network link capacity to maximize the transmission of gathered data from a source to a target. This paper describes a new method of link optimization of swarming mobile sensor networks. The new method is based on combination of the artificial potential force guaranteeing connectivities of the mobile sensor nodes and the max-flow min-cut theorem of graph theory ensuring optimization of the network link capacity. The developed algorithm is demonstrated and evaluated in simulation.

  11. EFPC: An Environmentally Friendly Power Control Scheme for Underwater Sensor Networks

    PubMed Central

    Yang, Qiuling; Su, Yishan; Jin, Zhigang; Yao, Guidan

    2015-01-01

    In oceans, the limited acoustic spectrum resource is heavily shared by marine mammals and manmade systems including underwater sensor networks. In order to limit the negative impact of acoustic signal on marine mammals, we propose an environmentally friendly power control (EFPC) scheme for underwater sensor networks. EFPC allocates transmission power of sensor nodes with a consideration of the existence of marine mammals. By applying a Nash Equilibrium based utility function with a set of limitations to optimize transmission power, the proposed power control algorithm can conduct parallel transmissions to improve the network’s goodput, while avoiding interference with marine mammals. Additionally, to localize marine mammals, which is a prerequisite of EFPC, we propose a novel passive hyperboloid localization algorithm (PHLA). PHLA passively localize marine mammals with the help of the acoustic characteristic of these targets. Simulation results show that PHLA can localize most of the target with a relatively small localization error and EFPC can achieve a close goodput performance compared with an existing power control algorithm while avoiding interfering with marine mammals. PMID:26593922

  12. Wireless surface acoustic wave sensors for displacement and crack monitoring in concrete structures

    NASA Astrophysics Data System (ADS)

    Perry, M.; McKeeman, I.; Saafi, M.; Niewczas, P.

    2016-03-01

    In this work, we demonstrate that wireless surface acoustic wave devices can be used to monitor millimetre displacements in crack opening during the cyclic and static loading of reinforced concrete structures. Sensors were packaged to extend their gauge length and to protect them against brittle fracture, before being surface-mounted onto the tensioned surface of a concrete beam. The accuracy of measurements was verified using computational methods and optical-fibre strain sensors. After packaging, the displacement and temperature resolutions of the surface acoustic wave sensors were 10 μ {{m}} and 2 °C respectively. With some further work, these devices could be retrofitted to existing concrete structures to facilitate wireless structural health monitoring.

  13. A methodology for analyzing an acoustic scene in sensor arrays

    NASA Astrophysics Data System (ADS)

    Man, Hong; Hohil, Myron E.; Desai, Sachi

    2007-10-01

    Presented here is a novel clustering method for Hidden Markov Models (HMMs) and its application in acoustic scene analysis. In this method, HMMs are clustered based on a similarity measure for stochastic models defined as the generalized probability product kernel (GPPK), which can be efficiently evaluated according to a fast algorithm introduced by Chen and Man (2005) [1]. Acoustic signals from various sources are partitioned into small frames. Frequency features are extracted from each of the frames to form observation vectors. These frames are further grouped into segments, and an HMM is trained from each of such segments. An unknown segment is categorized with a known event if its HMM has the closest similarity with the HMM from the corresponding labeled segment. Experiments are conducted on an underwater acoustic dataset from Steven Maritime Security Laboratory, Data set contains a swimmer signature, a noise signature from the Hudson River, and a test sequence with a swimmer in the Hudson River. Experimental results show that the proposed method can successfully associate the test sequence with the swimmer signature at very high confidence, despite their different time behaviors.

  14. Decentralized sensor fusion for Ubiquitous Networking Robotics in Urban Areas.

    PubMed

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

    2010-01-01

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

  15. Decentralized Sensor Fusion for Ubiquitous Networking Robotics in Urban Areas

    PubMed Central

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

    2010-01-01

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

  16. Neural Network-Based Sensor Validation for Turboshaft Engines

    NASA Technical Reports Server (NTRS)

    Moller, James C.; Litt, Jonathan S.; Guo, Ten-Huei

    1998-01-01

    Sensor failure detection, isolation, and accommodation using a neural network approach is described. An auto-associative neural network is configured to perform dimensionality reduction on the sensor measurement vector and provide estimated sensor values. The sensor validation scheme is applied in a simulation of the T700 turboshaft engine in closed loop operation. Performance is evaluated based on the ability to detect faults correctly and maintain stable and responsive engine operation. The set of sensor outputs used for engine control forms the network input vector. Analytical redundancy is verified by training networks of successively smaller bottleneck layer sizes. Training data generation and strategy are discussed. The engine maintained stable behavior in the presence of sensor hard failures. With proper selection of fault determination thresholds, stability was maintained in the presence of sensor soft failures.

  17. Decentralized sensor fusion for Ubiquitous Networking Robotics in Urban Areas.

    PubMed

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

    2010-01-01

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

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

    PubMed

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

    2012-01-01

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

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

    PubMed

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

    2012-01-01

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

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

    PubMed Central

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

    2012-01-01

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

  1. Water quality sensor placement in water networks with budget constraints.

    SciTech Connect

    Walski, Thomas M.; Uber, James G.; Hart, William Eugene; Phillips, Cynthia Ann; Berry, Jonathan W.

    2005-02-01

    In recent years, several integer programming models have been proposed to place sensors in municipal water networks in order to detect intentional or accidental contamination. Although these initial models assumed that it is equally costly to place a sensor at any place in the network, there clearly are practical cost constraints that would impact a sensor placement decision. Such constraints include not only labor costs but also the general accessibility of a sensor placement location. In this paper, we extend our integer program to explicitly model the cost of sensor placement. We partition network locations into groups of varying placement cost, and we consider the public health impacts of contamination events under varying budget constraints. Thus our models permit cost/benefit analyses for differing sensor placement designs. As a control for our optimization experiments, we compare the set of sensor locations selected by the optimization models to a set of manually-selected sensor locations.

  2. GAS MAIN SENSOR AND COMMUNICATIONS NETWORK SYSTEM

    SciTech Connect

    Hagen Schempf, Ph.D.

    2003-02-27

    Automatika, Inc. was contracted by the Department of Energy (DOE) and with co-funding from the New York Gas Group (NYGAS), to develop an in-pipe natural gas prototype measurement and wireless communications system for assessing and monitoring distribution networks. A prototype system was built for low-pressure cast-iron mains and tested in a spider- and serial-network configuration in a live network in Long Island with the support of Keyspan Energy, Inc. The prototype unit combined sensors capable of monitoring pressure, flow, humidity, temperature and vibration, which were sampled and combined in data-packages in an in-pipe master-slave architecture to collect data from a distributed spider-arrangement, and in a master-repeater-slave configuration in serial or ladder-network arrangements. It was found that the system was capable of performing all data-sampling and collection as expected, yielding interesting results as to flow-dynamics and vibration-detection. Wireless in-pipe communications were shown to be feasible and valuable data was collected in order to determine how to improve on range and data-quality in the future.

  3. Fast notification architecture for wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Hahk

    2013-03-01

    In an emergency, since it is vital to transmit the message to the users immediately after analysing the data to prevent disaster, this article presents the deployment of a fast notification architecture for a wireless sensor network. The sensor nodes of the proposed architecture can monitor an emergency situation periodically and transmit the sensing data, immediately to the sink node. We decide on the grade of fire situation according to the decision rule using the sensing values of temperature, CO, smoke density and temperature increasing rate. On the other hand, to estimate the grade of air pollution, the sensing data, such as dust, formaldehyde, NO2, CO2, is applied to the given knowledge model. Since the sink node in the architecture has a ZigBee interface, it can transmit the alert messages in real time according to analysed results received from the host server to the terminals equipped with a SIM card-type ZigBee module. Also, the host server notifies the situation to the registered users who have cellular phone through short message service server of the cellular network. Thus, the proposed architecture can adapt an emergency situation dynamically compared to the conventional architecture using video processing. In the testbed, after generating air pollution and fire data, the terminal receives the message in less than 3 s. In the test results, this system can also be applied to buildings and public areas where many people gather together, to prevent unexpected disasters in urban settings.

  4. Sensor Selection for Target Tracking in Wireless Sensor Networks With Uncertainty

    NASA Astrophysics Data System (ADS)

    Cao, Nianxia; Choi, Sora; Masazade, Engin; Varshney, Pramod K.

    2016-10-01

    In this paper, we propose a multiobjective optimization framework for the sensor selection problem in uncertain Wireless Sensor Networks (WSNs). The uncertainties of the WSNs result in a set of sensor observations with insufficient information about the target. We propose a novel mutual information upper bound (MIUB) based sensor selection scheme, which has low computational complexity, same as the Fisher information (FI) based sensor selection scheme, and gives estimation performance similar to the mutual information (MI) based sensor selection scheme. Without knowing the number of sensors to be selected a priori, the multiobjective optimization problem (MOP) gives a set of sensor selection strategies that reveal different trade-offs between two conflicting objectives: minimization of the number of selected sensors and minimization of the gap between the performance metric (MIUB and FI) when all the sensors transmit measurements and when only the selected sensors transmit their measurements based on the sensor selection strategy. Illustrative numerical results that provide valuable insights are presented.

  5. Integration of acoustical sensors into the KM3NeT optical modules

    SciTech Connect

    Enzenhöfer, A.; Collaboration: KM3NeT Collaboration

    2014-11-18

    The next generation multi-cubic-kilometre water Cherenkov neutrino telescope will be build in the Mediterranean Sea. This telescope, called KM3NeT, is currently entering a first construction phase. The KM3NeT research infrastructure will comprise 690 so-called Detection Units in its final design which will be anchored to the sea bed and held upright by submerged floats. The positions of these Detection Units, several hundred metres in length, and their attached Optical Modules for the detection of Cherenkov light have to be monitored continously to provide the telescope with its desired pointing precision. A standard way to do this is the utilisation of an acoustic positioning system using emitters at fixed positions and receivers distributed along the Detection Units. The KM3NeT neutrino telescope comprises a custom-made acoustic positioning system with newly designed emitters attached to the anchors of the Detection Units and custom-designed receivers attached to the Detection Units. This article describes an approach for a receiver and its performance. The proposed Opto-Acoustical Modules combine the optical sensors for the telescope with the acoustical sensors necessary for the positioning of the module itself. This combination leads to a compact design suited for an easy deployment of the numerous Detection Units. Furthermore, the instrumented volume can be used for scientific analyses such as marine science and acoustic particle detection.

  6. Measurement of cantilever vibration using impedance-loaded surface acoustic wave sensor

    NASA Astrophysics Data System (ADS)

    Oishi, Masaki; Hamashima, Hiromitsu; Kondoh, Jun

    2016-07-01

    In this study, an impedance-loaded surface acoustic wave (SAW) sensor was demonstrated to monitor the vibration frequency. Commercialized pressure sensors and a variable capacitor were chosen as external sensors, which were connected to a reflector on a SAW device. As the reflection coefficient of the reflector depended on the impedance, the echo amplitude was influenced by changes in the impedance of the external sensor. The vibration frequency of the cantilever was determined by monitoring the echo amplitude of the SAW device. Moreover, the attenuation constant of an envelope was estimated. The results of our feasibility study indicate that the impedance-loaded SAW sensor can be applied as a detector for structural health monitoring.

  7. Full bandwidth calibration procedure for acoustic probes containing a pressure and particle velocity sensor.

    PubMed

    Basten, Tom G H; de Bree, Hans-Elias

    2010-01-01

    Calibration of acoustic particle velocity sensors is still difficult due to the lack of standardized sensors to compare with. Recently it is shown by Jacobsen and Jaud [J. Acoust. Soc. Am. 120, 830-837 (2006)] that it is possible to calibrate a sound pressure and particle velocity sensor in free field conditions at higher frequencies. This is done by using the known acoustic impedance at a certain distance of a spherical loudspeaker. When the sound pressure is measured with a calibrated reference microphone, the particle velocity can be calculated from the known impedance and the measured pressure. At lower frequencies, this approach gives unreliable results. The method is now extended to lower frequencies by measuring the acoustic pressure inside the spherical source. At lower frequencies, the sound pressure inside the sphere is proportional to the movement of the loudspeaker membrane. If the movement is known, the particle velocity in front of the loudspeaker can be derived. This low frequency approach is combined with the high frequency approach giving a full bandwidth calibration procedure which can be used in free field conditions using a single calibration setup. The calibration results are compared with results obtained with a standing wave tube.

  8. A self-mixing based ring-type fiber-optic acoustic sensor

    NASA Astrophysics Data System (ADS)

    Wang, Lutang; Wu, Chunxu; Fang, Nian

    2014-07-01

    A novel, simple fiber-optic acoustic sensor consisting of a self-mixing effect based laser source and a ring-type interferometer is presented. With weak external optical feedbacks, the acoustic wave signals can be detected by measuring the changes of oscillating frequency of the laser diode, induced by the disturbances of sensing fiber, with the ring-type interferometer. The operation principles of the sensor system are explored in-depth and the experimental researches are carried out. The acoustic wave signals produced by various actions, such as by pencil broken, mental pin free falling and PZT are detected for evaluating the sensing performances of the experimental system. The investigation items include the sensitivity as well as frequency responses of the sensor system. An experiment for the detection of corona discharges is carried out, which occur in a high-voltage environment between two parallel copper electrodes, under different humidity levels. The satisfied experimental results are obtained. These experimental results well prove that our proposed sensing system has very high sensitivity and excellent high frequency responses characteristics in the detections of weak, high-frequency acoustic wave signals.

  9. Acoustic vibration sensor based on nonadiabatic tapered fibers.

    PubMed

    Xu, Ben; Li, Yi; Sun, Miao; Zhang, Zhen-Wei; Dong, Xin-Yong; Zhang, Zai-Xuan; Jin, Shang-Zhong

    2012-11-15

    A simple and low-cost vibration sensor based on single-mode nonadiabatic fiber tapers is proposed and demonstrated. The environmental vibrations can be detected by demodulating the transmission loss of the nonadiabatic fiber taper. Theoretical simulations show that the transmission loss is related to the microbending of the fiber taper induced by vibrations. Unlike interferometric sensors, this vibration sensor does not need any feedback loop to control the quadrature point to obtain a stable performance. In addition, it has no requirement for the coherence of the light source and is insensitive to temperature changes. Experimental results show that this sensing system has a wide frequency response range from a few hertz to tens of kilohertz with the maximal signal to noise ratio up to 73 dB.

  10. Complex monitoring and alert network for electromagnetic, infrasound, acoustic seismotectonic phenomena

    NASA Astrophysics Data System (ADS)

    -Emilian Toader, Victorin; Moldovan, Iren-Adelina; Constantin, Ionescu

    2014-05-01

    The Romanian seismicity recorded in 2013 three important events: the largest seismic "silence", the shortest sequence of two earthquakes greater than 4.8R in less than 14 days after the "Romanian National Institute for Earth Physics" (NIEP) developed a digital network, and a very high crustal activity in Galati area. We analyze the variations of the telluric currents and local magnetic field, variations of the atmospheric electrostatic field, infrasound, temperature, humidity, wind speed and direction, atmospheric pressure, variations in the earth crust with inclinometers and animal behavior. The general effect is the first high seismic energy discontinuity that could be a precursor factor. Since 1977 Romania did not register any important earthquake that would generate a sense of fear among the population. In parallel with the seismic network NIEP developed a magneto-telluric, bioseismic, VLF and acoustic network. A large frequency spectrum is covered for mechanical vibration, magnetic and electric field with ground and air sensors. Special software was designed for acquisition, analysis and real time alert using internet direct connection, web page, email and SMS. Many examples show the sensitivity of telluric current, infrasound, acoustic records (from air-ground), and the effect of tectonic stress on the magnetic field or ground deformation. The next update of the multidisciplinary monitoring network will include measurement of ionization, radon emission, sky color, solar radiation and extension of infrasound and VL/LF equipment. NOAA Space Weather satellites transmit solar activity magnetic field data, X ray flux, electron, and proton flux information useful for complex analysis.

  11. Automated sensor networks to advance ocean science

    NASA Astrophysics Data System (ADS)

    Schofield, O.; Orcutt, J. A.; Arrott, M.; Vernon, F. L.; Peach, C. L.; Meisinger, M.; Krueger, I.; Kleinert, J.; Chao, Y.; Chien, S.; Thompson, D. R.; Chave, A. D.; Balasuriya, A.

    2010-12-01

    The National Science Foundation has funded the Ocean Observatories Initiative (OOI), which over the next five years will deploy infrastructure to expand scientist’s ability to remotely study the ocean. The deployed infrastructure will be linked by a robust cyberinfrastructure (CI) that will integrate marine observatories into a coherent system-of-systems. OOI is committed to engaging the ocean sciences community during the construction pahse. For the CI, this is being enabled by using a “spiral design strategy” allowing for input throughout the construction phase. In Fall 2009, the OOI CI development team used an existing ocean observing network in the Mid-Atlantic Bight (MAB) to test OOI CI software. The objective of this CI test was to aggregate data from ships, autonomous underwater vehicles (AUVs), shore-based radars, and satellites and make it available to five different data-assimilating ocean forecast models. Scientists used these multi-model forecasts to automate future glider missions in order to demonstrate the feasibility of two-way interactivity between the sensor web and predictive models. The CI software coordinated and prioritized the shared resources that allowed for the semi-automated reconfiguration of assett-tasking, and thus enabled an autonomous execution of observation plans for the fixed and mobile observation platforms. Efforts were coordinated through a web portal that provided an access point for the observational data and model forecasts. Researchers could use the CI software in tandem with the web data portal to assess the performance of individual numerical model results, or multi-model ensembles, through real-time comparisons with satellite, shore-based radar, and in situ robotic measurements. The resulting sensor net will enable a new means to explore and study the world’s oceans by providing scientists a responsive network in the world’s oceans that can be accessed via any wireless network.

  12. Acoustic-sensor-based detection of damage in composite aircraft structures

    NASA Astrophysics Data System (ADS)

    Foote, Peter; Martin, Tony; Read, Ian

    2004-03-01

    Acoustic emission detection is a well-established method of locating and monitoring crack development in metal structures. The technique has been adapted to test facilities for non-destructive testing applications. Deployment as an operational or on-line automated damage detection technology in vehicles is posing greater challenges. A clear requirement of potential end-users of such systems is a level of automation capable of delivering low-level diagnosis information. The output from the system is in the form of "go", "no-go" indications of structural integrity or immediate maintenance actions. This level of automation requires significant data reduction and processing. This paper describes recent trials of acoustic emission detection technology for the diagnosis of damage in composite aerospace structures. The technology comprises low profile detection sensors using piezo electric wafers encapsulated in polymer film ad optical sensors. Sensors are bonded to the structure"s surface and enable acoustic events from the loaded structure to be located by triangulation. Instrumentation has been enveloped to capture and parameterise the sensor data in a form suitable for low-bandwidth storage and transmission.

  13. High-temperature acoustic emission sensing tests using a yttrium calcium oxyborate sensor.

    PubMed

    Johnson, Joseph A; Kim, Kyungrim; Zhang, Shujun; Wu, Di; Jiang, Xiaoning

    2014-05-01

    Piezoelectric materials have been broadly utilized in acoustic emission sensors, but are often hindered by the loss of piezoelectric properties at temperatures in the 500°C to 700°C range or higher. In this paper, a piezoelectric acoustic emission sensor was designed and fabricated using yttrium calcium oxyborate (YCOB) single crystals, followed by Hsu-Nielsen tests for high-temperature (>700°C) applications. The sensitivity of the YCOB sensor was found to have minimal degradation with increasing temperature up to 1000°C. During Hsu-Nielsen tests with a steel bar, this YCOB acoustic sensor showed the ability to detect zero-order symmetric and antisymmetric modes at 30 and 120 kHz, respectively, as well as distinguish a first-order antisymmetric mode at 240 kHz at elevated temperatures up to 1000°C. The frequency characteristics of the signal were verified using a finite-element model and wavelet transformation analysis.

  14. Experimental Results of Underwater Cooperative Source Localization Using a Single Acoustic Vector Sensor

    PubMed Central

    Felisberto, Paulo; Rodriguez, Orlando; Santos, Paulo; Ey, Emanuel; Jesus, Sérgio M.

    2013-01-01

    This paper aims at estimating the azimuth, range and depth of a cooperative broadband acoustic source with a single vector sensor in a multipath underwater environment, where the received signal is assumed to be a linear combination of echoes of the source emitted waveform. A vector sensor is a device that measures the scalar acoustic pressure field and the vectorial acoustic particle velocity field at a single location in space. The amplitudes of the echoes in the vector sensor components allow one to determine their azimuth and elevation. Assuming that the environmental conditions of the channel are known, source range and depth are obtained from the estimates of elevation and relative time delays of the different echoes using a ray-based backpropagation algorithm. The proposed method is tested using simulated data and is further applied to experimental data from the Makai'05 experiment, where 8–14 kHz chirp signals were acquired by a vector sensor array. It is shown that for short ranges, the position of the source is estimated in agreement with the geometry of the experiment. The method is low computational demanding, thus well-suited to be used in mobile and light platforms, where space and power requirements are limited. PMID:23857257

  15. Multipoint dynamically reconfigure adaptive distributed fiber optic acoustic emission sensor (FAESense) system for condition based maintenance

    NASA Astrophysics Data System (ADS)

    Mendoza, Edgar; Prohaska, John; Kempen, Connie; Esterkin, Yan; Sun, Sunjian; Krishnaswamy, Sridhar

    2010-09-01

    This paper describes preliminary results obtained under a Navy SBIR contract by Redondo Optics Inc. (ROI), in collaboration with Northwestern University towards the development and demonstration of a next generation, stand-alone and fully integrated, dynamically reconfigurable, adaptive fiber optic acoustic emission sensor (FAESense™) system for the in-situ unattended detection and localization of shock events, impact damage, cracks, voids, and delaminations in new and aging critical infrastructures found in ships, submarines, aircraft, and in next generation weapon systems. ROI's FAESense™ system is based on the integration of proven state-of-the-art technologies: 1) distributed array of in-line fiber Bragg gratings (FBGs) sensors sensitive to strain, vibration, and acoustic emissions, 2) adaptive spectral demodulation of FBG sensor dynamic signals using two-wave mixing interferometry on photorefractive semiconductors, and 3) integration of all the sensor system passive and active optoelectronic components within a 0.5-cm x 1-cm photonic integrated circuit microchip. The adaptive TWM demodulation methodology allows the measurement of dynamic high frequnency acoustic emission events, while compensating for passive quasi-static strain and temperature drifts. It features a compact, low power, environmentally robust 1-inch x 1-inch x 4-inch small form factor (SFF) package with no moving parts. The FAESense™ interrogation system is microprocessor-controlled using high data rate signal processing electronics for the FBG sensors calibration, temperature compensation and the detection and analysis of acoustic emission signals. Its miniaturized package, low power operation, state-of-the-art data communications, and low cost makes it a very attractive solution for a large number of applications in naval and maritime industries, aerospace, civil structures, the oil and chemical industry, and for homeland security applications.

  16. Learning a detection map for a network of unattended ground sensors.

    SciTech Connect

    Nguyen, Hung D.; Koch, Mark William

    2010-03-01

    We have developed algorithms to automatically learn a detection map of a deployed sensor field for a virtual presence and extended defense (VPED) system without apriori knowledge of the local terrain. The VPED system is an unattended network of sensor pods, with each pod containing acoustic and seismic sensors. Each pod has the ability to detect and classify moving targets at a limited range. By using a network of pods we can form a virtual perimeter with each pod responsible for a certain section of the perimeter. The site's geography and soil conditions can affect the detection performance of the pods. Thus, a network in the field may not have the same performance as a network designed in the lab. To solve this problem we automatically estimate a network's detection performance as it is being installed at a site by a mobile deployment unit (MDU). The MDU will wear a GPS unit, so the system not only knows when it can detect the MDU, but also the MDU's location. In this paper, we demonstrate how to handle anisotropic sensor-configurations, geography, and soil conditions.

  17. A smart sensor system for trace organic vapor detection using a temperature-controlled array of surface acoustic wave vapor sensors, automated preconcentrator tubes, and pattern recognition

    SciTech Connect

    Grate, J.W.; Rose-Pehrsson, S.L.; Klusty, M.; Wohltjen, H.

    1993-05-01

    A smart sensor system for the detection, of toxic organophosphorus and toxic organosulfur vapors at trace concentrations has been designed, fabricated, and tested against a wide variety of vapor challenges. The key features of the system are: An array of four surface acoustic wave (SAW) vapor sensors, temperature control of the vapor sensors, the use of pattern recognition to analyze the sensor data, and an automated sampling system including thermally-desorbed preconcentrator tubes (PCTs).

  18. Data Transport in a Novel Wireless Sensor Network

    SciTech Connect

    Roberts, R S

    2001-06-01

    The deployment and operation of large wireless sensor networks can pose difficult problems, particularly in time critical situations, over large geographic areas, or in rugged terrain. An approach to this problem is to use unmanned air vehicles to first deploy the sensors, and then provide communication services to the sensors. This paper presents a network model that describes the flow of data through such a sensor network. Simulation results are presented that illustrate the behavior of the data flow in steady state and transient conditions.

  19. Wireless Sensor Networks for Environmental Monitoring

    NASA Astrophysics Data System (ADS)

    Liang, X.; Liang, Y.; Navarro, M.; Zhong, X.; Villalba, G.; Li, Y.; Davis, T.; Erratt, N.

    2015-12-01

    Wireless sensor networks (WSNs) have gained an increasing interest in a broad range of new scientific research and applications. WSN technologies can provide high resolution for spatial and temporal data which has not been possible before, opening up new opportunities. On the other hand, WSNs, particularly outdoor WSNs in harsh environments, present great challenges for scientists and engineers in terms of the network design, deployment, operation, management, and maintenance. Since 2010, we have been working on the deployment of an outdoor multi-hop WSN testbed for hydrological/environmental monitoring in a forested hill-sloped region at the Audubon Society of Western Pennsylvania (ASWP), Pennsylvania, USA. The ASWP WSN testbed has continuously evolved and had more than 80 nodes by now. To our knowledge, the ASWP WSN testbed represents one of the first known long-term multi-hop WSN deployments in an outdoor environment. As simulation and laboratory methods are unable to capture the complexity of outdoor environments (e.g., forests, oceans, mountains, or glaciers), which significantly affect WSN operations and maintenance, experimental deployments are essential to investigate and understand WSN behaviors and performances as well as its maintenance characteristics under these harsh conditions. In this talk, based on our empirical studies with the ASWP WSN testbed, we will present our discoveries and investigations on several important aspects including WSN energy profile, node reprogramming, network management system, and testbed maintenance. We will then provide our insight into these critical aspects of outdoor WSN deployments and operations.

  20. Wireless sensor network for irrigation application in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wireless sensor network was deployed in a cotton field to monitor soil water status for irrigation. The network included two systems, a Decagon system and a microcontroller-based system. The Decagon system consists of soil volumetric water-content sensors, wireless data loggers, and a central data...

  1. Wireless sensor network effectively controls center pivot irrigation of sorghum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Robust automatic irrigation scheduling has been demonstrated using wired sensors and sensor network systems with subsurface drip and moving irrigation systems. However, there are limited studies that report on crop yield and water use efficiency resulting from the use of wireless networks to automat...

  2. Bluetooth Roaming for Sensor Network System in Clinical Environment.

    PubMed

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

    2015-01-01

    A sensor network is key infrastructure for advancing a hospital information system (HIS). The authors proposed a method to provide roaming functionality for Bluetooth to realize a Bluetooth-based sensor network, which is suitable to connect clinical devices. The proposed method makes the average response time of a Bluetooth connection less than one second by making the master device repeat the inquiry process endlessly and modifies parameters of the inquiry process. The authors applied the developed sensor network for daily clinical activities in an university hospital, and confirmed the stabilitya and effectiveness of the sensor network. As Bluetooth becomes a quite common wireless interface for medical devices, the proposed protocol that realizes Bluetooth-based sensor network enables HIS to equip various clinical devices and, consequently, lets information and communication technologies advance clinical services. PMID:26262038

  3. Bluetooth Roaming for Sensor Network System in Clinical Environment.

    PubMed

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

    2015-01-01

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

  4. Method and apparatus for measuring surface changes, in porous materials, using multiple differently-configured acoustic sensors

    DOEpatents

    Hietala, Susan Leslie; Hietala, Vincent Mark; Tigges, Chris Phillip

    2001-01-01

    A method and apparatus for measuring surface changes, such as mass uptake at various pressures, in a thin-film material, in particular porous membranes, using multiple differently-configured acoustic sensors.

  5. A new capnograph based on an electro acoustic sensor.

    PubMed

    Folke, M; Hök, B

    2008-01-01

    End tidal carbon dioxide measurements with an electro acoustic capnograph prototype have been demonstrated. The aim of this study was to verify that it is possible to obtain an adequate capnogram using the prototype and to investigate the influence of ambient temperature and humidity variations. By simultaneous measurements with a reference capnograph, on subjects performing exercise, hypo- and hyperventilation, P(ET)CO(2) readings from the reference were compared with the output signal from the prototype. The capnogram from the prototype correlated well with the reference in terms of breath time. The first parts of the expiration and inspiration phases were steeper for the reference than the prototype. The output signal from the prototype correlated well with the reference P(ET)CO(2) readings with a correlation coefficient of 0.93 at varied temperature and relative humidity. PMID:17846809

  6. A cantilever based optical fiber acoustic sensor fabricated by femtosecond laser micromachining

    NASA Astrophysics Data System (ADS)

    Liu, Jie; Yuan, Lei; Huang, Jie; Xiao, Hai

    2016-04-01

    In this paper, we present a pure silica micro-cantilever based optical fiber sensor for acoustic wave detection. The cantilever is directly fabricated by fs laser micromachining on an optical fiber tip functioning as an inline Fabry-Perot interferometer (FPI). The applied acoustic wave pressurizes the micro-cantilever beam and the corresponding dynamic signals can be probed by the FPI. The thickness, length, and width of the micro-cantilever beam can be flexibly designed and fabricated so that the sensitivity, frequency response, and the total measurement range can be varied to fit many practical applications. Experimental results will be presented and analyzed. Due to the assembly free fabrication of the fs-laser, multiple micro-cantilever beams could be potentially fabricated in/on a single optical fiber for quasi-distributed acoustic mapping with high spatial resolution.

  7. Source Localization with Acoustic Sensor Arrays Using Generative Model Based Fitting with Sparse Constraints

    PubMed Central

    Velasco, Jose; Pizarro, Daniel; Macias-Guarasa, Javier

    2012-01-01

    This paper presents a novel approach for indoor acoustic source localization using sensor arrays. The proposed solution starts by defining a generative model, designed to explain the acoustic power maps obtained by Steered Response Power (SRP) strategies. An optimization approach is then proposed to fit the model to real input SRP data and estimate the position of the acoustic source. Adequately fitting the model to real SRP data, where noise and other unmodelled effects distort the ideal signal, is the core contribution of the paper. Two basic strategies in the optimization are proposed. First, sparse constraints in the parameters of the model are included, enforcing the number of simultaneous active sources to be limited. Second, subspace analysis is used to filter out portions of the input signal that cannot be explained by the model. Experimental results on a realistic speech database show statistically significant localization error reductions of up to 30% when compared with the SRP-PHAT strategies. PMID:23202021

  8. GAS MAIN SENSOR AND COMMUNICATIONS NETWORK SYSTEM

    SciTech Connect

    Hagen Schempf

    2004-09-30

    Automatika, Inc. was contracted by the Department of Energy (DOE) and with co-funding from the New York Gas Group (NYGAS), to develop an in-pipe natural gas prototype measurement and wireless communications system for assessing and monitoring distribution networks. In Phase II of this three-phase program, an improved prototype system was built for low-pressure cast-iron and high-pressure steel (including a no-blow installation system) mains and tested in a serial-network configuration in a live network in Long Island with the support of Keyspan Energy, Inc. The experiment was carried out in several open-hole excavations over a multi-day period. The prototype units (3 total) combined sensors capable of monitoring pressure, flow, humidity, temperature and vibration, which were sampled and combined in data-packages in an in-pipe master-repeater-slave configuration in serial or ladder-network arrangements. It was verified that the system was capable of performing all data-sampling, data-storage and collection as expected, yielding interesting results as to flow-dynamics and vibration-detection. Wireless in-pipe communications were shown to be feasible and the system was demonstrated to run off in-ground battery- and above-ground solar power. The remote datalogger access and storage-card features were demonstrated and used to log and post-process system data. Real-time data-display on an updated Phase-I GUI was used for in-field demonstration and troubleshooting.

  9. Defense applications of disposable organic sensor networks

    NASA Astrophysics Data System (ADS)

    Beale, Dean A. R.; Hume, Andrew L.; Hodges, Ruth N.; Calloway, Vince P.; Kimber, Steve D.

    2004-11-01

    The nature of many current Intelligence, Surveillance, Target Acquisition and Reconnaissance (ISTAR) sensor systems requires that they are controlled at an operational or strategic level. The trend towards asymmetric/urban warfare has created the necessity for tactical commanders to be empowered with a similar ISTAR capability but over a reduced area. The variable temporal, spatial and cost constraints imposed by each scenario requires an adaptable organic sensory system to be developed to support the tactical commander. Unmanned Disposable Organic Sensor Networks (DOSNs) are promising to provide sensory solutions in many tactical situations. However in order to develop a suitable DOSN it is necessary to identify the optimum realisation to meet the tactical commanders requirements. In this paper the work conducted by QinetiQ for elements of the UK MOD is discussed. This includes: 1) A method for assessing the value of each specific realisation of a DOSN against a range of scenarios. 2) Description of models used to generate an understanding of the capability of DOSN systems. 3) Description of an experimental DOSN system with associated trial results and plans to validate the models discussed above. The technical approach employed could also be used to assess the applicability of DOSN systems across a range of other military ISTAR requirements.

  10. A novel optimal sensitivity design scheme for yarn tension sensor using surface acoustic wave device.

    PubMed

    Lei, Bingbing; Lu, Wenke; Zhu, Changchun; Liu, Qinghong; Zhang, Haoxin

    2014-08-01

    In this paper, we propose a novel optimal sensitivity design scheme for the yarn tension sensor using surface acoustic wave (SAW) device. In order to obtain the best sensitivity, the regression model between the size of the SAW yarn tension sensor substrate and the sensitivity of the SAW yarn tension sensor was established using the least square method. The model was validated too. Through analyzing the correspondence between the regression function monotonicity and its partial derivative sign, the effect of the SAW yarn tension sensor substrate size on the sensitivity of the SAW yarn tension sensor was investigated. Based on the regression model, a linear programming model was established to gain the optimal sensitivity of the SAW yarn tension sensor. The linear programming result shows that the maximum sensitivity will be achieved when the SAW yarn tension sensor substrate length is equal to 15 mm and its width is equal to 3mm within a fixed interval of the substrate size. An experiment of SAW yarn tension sensor about 15 mm long and 3mm wide was presented. Experimental results show that the maximum sensitivity 1982.39 Hz/g was accomplished, which confirms that the optimal sensitivity design scheme is useful and effective.

  11. Surface Acoustic Wave Ammonia Sensors Based on ST-cut Quartz under Periodic Al Structure

    PubMed Central

    Hsu, Cheng-Liang; Shen, Chi-Yen; Tsai, Rume-Tze; Su, Ming-Yau

    2009-01-01

    Surface acoustic wave (SAW) devices are key components for sensing applications. SAW propagation under a periodic grating was investigated in this work. The theoretical method used here is the space harmonic method. We also applied the results of SAW propagation studied in this work to design a two-port resonator with an Al grating on ST-cut quartz. The measured frequency responses of the resonator were similar to the simulation ones. Then, the chemical interface of polyaniline/WO3 composites was coated on the SAW sensor for ammonia detection. The SAW sensor responded to ammonia gas and could be regenerated using dry nitrogen. PMID:22399951

  12. Contributed Review: Recent developments in acoustic energy harvesting for autonomous wireless sensor nodes applications.

    PubMed

    Khan, Farid Ullah; Khattak, Muhammad Umair

    2016-02-01

    Rapid developments in micro electronics, micro fabrication, ultra-large scale of integration, ultra-low power sensors, and wireless technology have greatly reduced the power consumption requirements of wireless sensor nodes (WSNs) and make it possible to operate these devices with energy harvesters. Likewise, other energy harvesters, acoustic energy harvesters (AEHs), have been developed and are gaining swift interest in last few years. This paper presents a review of AEHs reported in the literature for the applications of WSNs. Based on transduction mechanism, there are two types of AEHs: piezoelectric acoustic energy harvesters (PEAEHs) and electromagnetic acoustic energy harvesters (EMAEHs). The reported AEHs are mostly characterized under the sound pressure level (SPL) that ranges from 45 to 161 dB. The range for resonant frequency of the produced AEHs is from 146 Hz to 24 kHz and these produced 0.68 × 10(-6) μW to 30 mW power. The maximum power (30 mW) is produced by a PEAEH, when the harvester is subjected to a SPL of 161 dB and 2.64 kHz frequency. However, for EMAEHs, the maximum power reported is about 1.96 mW (at 125 dB and 143 Hz). Under the comparable SPLs, the power production by the reported EMAEHs is relatively better than that of PEAEHs, moreover, due to lower resonant frequency, the EMAEHs are more feasible for the low frequency band acoustical environment. PMID:26931827

  13. A Finite Element Model of a MEMS-based Surface Acoustic Wave Hydrogen Sensor

    PubMed Central

    EL Gowini, Mohamed M.; Moussa, Walied A.

    2010-01-01

    Hydrogen plays a significant role in various industrial applications, but careful handling and continuous monitoring are crucial since it is explosive when mixed with air. Surface Acoustic Wave (SAW) sensors provide desirable characteristics for hydrogen detection due to their small size, low fabrication cost, ease of integration and high sensitivity. In this paper a finite element model of a Surface Acoustic Wave sensor is developed using ANSYS12© and tested for hydrogen detection. The sensor consists of a YZ-lithium niobate substrate with interdigital electrodes (IDT) patterned on the surface. A thin palladium (Pd) film is added on the surface of the sensor due to its high affinity for hydrogen. With increased hydrogen absorption the palladium hydride structure undergoes a phase change due to the formation of the β-phase, which deteriorates the crystal structure. Therefore with increasing hydrogen concentration the stiffness and the density are significantly reduced. The values of the modulus of elasticity and the density at different hydrogen concentrations in palladium are utilized in the finite element model to determine the corresponding SAW sensor response. Results indicate that with increasing the hydrogen concentration the wave velocity decreases and the attenuation of the wave is reduced. PMID:22205865

  14. Damage detection using the signal entropy of an ultrasonic sensor network

    NASA Astrophysics Data System (ADS)

    Rojas, E.; Baltazar, A.; Loh, K. J.

    2015-07-01

    Piezoelectric ultrasonic sensors used to propagate guided waves can potentially be implemented to inspect large areas in engineering structures. However, the inherent dispersion and noise of guided acoustic signals, multiple echoes in the structure, as well as a lack of an approximate or exact model, limit their use as a continuous structural health monitoring system. In this work, the implementation of a network of piezoelectric sensors randomly placed on a plate-like structure to detect and locate artificial damage is studied. A network of macro fiber composite (MFC) sensors working in a pitch-catch configuration was set on an aluminum thin plate 1.9 mm in thickness. Signals were analyzed in the time-scale domain using the discrete wavelet transform. The objectives of this work were threefold, namely to first develop a damage index based on the entropy distribution using short time wavelet entropy of the ultrasonic waves generated by a sensor network, second to determine the performance of an array of spare MFC sensors to detect artificial damage, and third to implement a time-of-arrival (TOA) algorithm on the gathered signals for damage location of an artificial circular discontinuity. Our preliminary test results show that the proposed methodology provides sufficient information for damage detection, which, once combined with the TOA algorithm, allows localization of the damage.

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

    PubMed

    Halim, Dunant; Cheng, Li; Su, Zhongqing

    2011-04-01

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

  16. IJA: an efficient algorithm for query processing in sensor networks.

    PubMed

    Lee, Hyun Chang; Lee, Young Jae; Lim, Ji Hyang; Kim, Dong Hwa

    2011-01-01

    One of main features in sensor networks is the function that processes real time state information after gathering needed data from many domains. The component technologies consisting of each node called a sensor node that are including physical sensors, processors, actuators and power have advanced significantly over the last decade. Thanks to the advanced technology, over time sensor networks have been adopted in an all-round industry sensing physical phenomenon. However, sensor nodes in sensor networks are considerably constrained because with their energy and memory resources they have a very limited ability to process any information compared to conventional computer systems. Thus query processing over the nodes should be constrained because of their limitations. Due to the problems, the join operations in sensor networks are typically processed in a distributed manner over a set of nodes and have been studied. By way of example while simple queries, such as select and aggregate queries, in sensor networks have been addressed in the literature, the processing of join queries in sensor networks remains to be investigated. Therefore, in this paper, we propose and describe an Incremental Join Algorithm (IJA) in Sensor Networks to reduce the overhead caused by moving a join pair to the final join node or to minimize the communication cost that is the main consumer of the battery when processing the distributed queries in sensor networks environments. At the same time, the simulation result shows that the proposed IJA algorithm significantly reduces the number of bytes to be moved to join nodes compared to the popular synopsis join algorithm. PMID:22319375

  17. A Novel Cooperative Opportunistic Routing Scheme for Underwater Sensor Networks.

    PubMed

    Ghoreyshi, Seyed Mohammad; Shahrabi, Alireza; Boutaleb, Tuleen

    2016-01-01

    Increasing attention has recently been devoted to underwater sensor networks (UWSNs) because of their capabilities in the ocean monitoring and resource discovery. UWSNs are faced with different challenges, the most notable of which is perhaps how to efficiently deliver packets taking into account all of the constraints of the available acoustic communication channel. The opportunistic routing provides a reliable solution with the aid of intermediate nodes' collaboration to relay a packet toward the destination. In this paper, we propose a new routing protocol, called opportunistic void avoidance routing (OVAR), to address the void problem and also the energy-reliability trade-off in the forwarding set selection. OVAR takes advantage of distributed beaconing, constructs the adjacency graph at each hop and selects a forwarding set that holds the best trade-off between reliability and energy efficiency. The unique features of OVAR in selecting the candidate nodes in the vicinity of each other leads to the resolution of the hidden node problem. OVAR is also able to select the forwarding set in any direction from the sender, which increases its flexibility to bypass any kind of void area with the minimum deviation from the optimal path. The results of our extensive simulation study show that OVAR outperforms other protocols in terms of the packet delivery ratio, energy consumption, end-to-end delay, hop count and traversed distance. PMID:26927118

  18. A Novel Cooperative Opportunistic Routing Scheme for Underwater Sensor Networks.

    PubMed

    Ghoreyshi, Seyed Mohammad; Shahrabi, Alireza; Boutaleb, Tuleen

    2016-01-01

    Increasing attention has recently been devoted to underwater sensor networks (UWSNs) because of their capabilities in the ocean monitoring and resource discovery. UWSNs are faced with different challenges, the most notable of which is perhaps how to efficiently deliver packets taking into account all of the constraints of the available acoustic communication channel. The opportunistic routing provides a reliable solution with the aid of intermediate nodes' collaboration to relay a packet toward the destination. In this paper, we propose a new routing protocol, called opportunistic void avoidance routing (OVAR), to address the void problem and also the energy-reliability trade-off in the forwarding set selection. OVAR takes advantage of distributed beaconing, constructs the adjacency graph at each hop and selects a forwarding set that holds the best trade-off between reliability and energy efficiency. The unique features of OVAR in selecting the candidate nodes in the vicinity of each other leads to the resolution of the hidden node problem. OVAR is also able to select the forwarding set in any direction from the sender, which increases its flexibility to bypass any kind of void area with the minimum deviation from the optimal path. The results of our extensive simulation study show that OVAR outperforms other protocols in terms of the packet delivery ratio, energy consumption, end-to-end delay, hop count and traversed distance.

  19. A Novel Cooperative Opportunistic Routing Scheme for Underwater Sensor Networks

    PubMed Central

    Ghoreyshi, Seyed Mohammad; Shahrabi, Alireza; Boutaleb, Tuleen

    2016-01-01

    Increasing attention has recently been devoted to underwater sensor networks (UWSNs) because of their capabilities in the ocean monitoring and resource discovery. UWSNs are faced with different challenges, the most notable of which is perhaps how to efficiently deliver packets taking into account all of the constraints of the available acoustic communication channel. The opportunistic routing provides a reliable solution with the aid of intermediate nodes’ collaboration to relay a packet toward the destination. In this paper, we propose a new routing protocol, called opportunistic void avoidance routing (OVAR), to address the void problem and also the energy-reliability trade-off in the forwarding set selection. OVAR takes advantage of distributed beaconing, constructs the adjacency graph at each hop and selects a forwarding set that holds the best trade-off between reliability and energy efficiency. The unique features of OVAR in selecting the candidate nodes in the vicinity of each other leads to the resolution of the hidden node problem. OVAR is also able to select the forwarding set in any direction from the sender, which increases its flexibility to bypass any kind of void area with the minimum deviation from the optimal path. The results of our extensive simulation study show that OVAR outperforms other protocols in terms of the packet delivery ratio, energy consumption, end-to-end delay, hop count and traversed distance. PMID:26927118

  20. Development of a multi-channel piezoelectric acoustic sensor based on an artificial basilar membrane.

    PubMed

    Jung, Youngdo; Kwak, Jun-Hyuk; Lee, Young Hwa; Kim, Wan Doo; Hur, Shin

    2013-12-20

    In this research, we have developed a multi-channel piezoelectric acoustic sensor (McPAS) that mimics the function of the natural basilar membrane capable of separating incoming acoustic signals mechanically by their frequency and generating corresponding electrical signals. The McPAS operates without an external energy source and signal processing unit with a vibrating piezoelectric thin film membrane. The shape of the vibrating membrane was chosen to be trapezoidal such that different locations of membrane have different local resonance frequencies. The length of the membrane is 28 mm and the width of the membrane varies from 1 mm to 8 mm. Multiphysics finite element analysis (FEA) was carried out to predict and design the mechanical behaviors and piezoelectric response of the McPAS model. The designed McPAS was fabricated with a MEMS fabrication process based on the simulated results. The fabricated device was tested with a mouth simulator to measure its mechanical and piezoelectrical frequency response with a laser Doppler vibrometer and acoustic signal analyzer. The experimental results show that the as fabricated McPAS can successfully separate incoming acoustic signals within the 2.5 kHz-13.5 kHz range and the maximum electrical signal output upon acoustic signal input of 94 dBSPL was 6.33 mVpp. The performance of the fabricated McPAS coincided well with the designed parameters.

  1. Development of a Multi-Channel Piezoelectric Acoustic Sensor Based on an Artificial Basilar Membrane

    PubMed Central

    Jung, Youngdo; Kwak, Jun-Hyuk; Lee, Young Hwa; Kim, Wan Doo; Hur, Shin

    2014-01-01

    In this research, we have developed a multi-channel piezoelectric acoustic sensor (McPAS) that mimics the function of the natural basilar membrane capable of separating incoming acoustic signals mechanically by their frequency and generating corresponding electrical signals. The McPAS operates without an external energy source and signal processing unit with a vibrating piezoelectric thin film membrane. The shape of the vibrating membrane was chosen to be trapezoidal such that different locations of membrane have different local resonance frequencies. The length of the membrane is 28 mm and the width of the membrane varies from 1 mm to 8 mm. Multiphysics finite element analysis (FEA) was carried out to predict and design the mechanical behaviors and piezoelectric response of the McPAS model. The designed McPAS was fabricated with a MEMS fabrication process based on the simulated results. The fabricated device was tested with a mouth simulator to measure its mechanical and piezoelectrical frequency response with a laser Doppler vibrometer and acoustic signal analyzer. The experimental results show that the as fabricated McPAS can successfully separate incoming acoustic signals within the 2.5 kHz–13.5 kHz range and the maximum electrical signal output upon acoustic signal input of 94 dBSPL was 6.33 mVpp. The performance of the fabricated McPAS coincided well with the designed parameters. PMID:24361926

  2. Acoustic power measurement of high-intensity focused ultrasound transducer using a pressure sensor.

    PubMed

    Zhou, Yufeng

    2015-03-01

    The acoustic power of high-intensity focused ultrasound (HIFU) is an important parameter that should be measured prior to each treatment to guarantee effective and safe outcomes. A new calibration technique was developed that involves estimating the pressure distribution, calculating the acoustic power using an underwater pressure blast sensor, and compensating the contribution of harmonics to the acoustic power. The output of a clinical extracorporeal HIFU system (center frequency of ~1 MHz, p+ = 2.5-57.2 MPa, p(-) = -1.8 to -13.9 MPa, I(SPPA) = 513-22,940 W/cm(2), -6 dB size of 1.6 × 10 mm: lateral × axial) was measured using this approach and then compared with that obtained using a radiation force balance. Similarities were found between each method at acoustic power ranging from 18.2 W to 912 W with an electrical-to-acoustic conversion efficiency of ~42%. The proposed method has advantages of low weight, smaller size, high sensitivity, quick response, high signal-to-noise ratio (especially at low power output), robust performance, and easy operation of HIFU exposimetry measurement.

  3. Acoustic power measurement of high-intensity focused ultrasound transducer using a pressure sensor.

    PubMed

    Zhou, Yufeng

    2015-03-01

    The acoustic power of high-intensity focused ultrasound (HIFU) is an important parameter that should be measured prior to each treatment to guarantee effective and safe outcomes. A new calibration technique was developed that involves estimating the pressure distribution, calculating the acoustic power using an underwater pressure blast sensor, and compensating the contribution of harmonics to the acoustic power. The output of a clinical extracorporeal HIFU system (center frequency of ~1 MHz, p+ = 2.5-57.2 MPa, p(-) = -1.8 to -13.9 MPa, I(SPPA) = 513-22,940 W/cm(2), -6 dB size of 1.6 × 10 mm: lateral × axial) was measured using this approach and then compared with that obtained using a radiation force balance. Similarities were found between each method at acoustic power ranging from 18.2 W to 912 W with an electrical-to-acoustic conversion efficiency of ~42%. The proposed method has advantages of low weight, smaller size, high sensitivity, quick response, high signal-to-noise ratio (especially at low power output), robust performance, and easy operation of HIFU exposimetry measurement. PMID:25659300

  4. NATO TG-25 joint field experiment in distributed sensor networks

    NASA Astrophysics Data System (ADS)

    Mays, Brian; Vu, Hao; Srour, Nino

    2003-09-01

    NATO's Task Group (TG-25) on acoustic and seismic sensing is responsible for assessing the potential technologies that can be cooperatively developed and shared within NATO's countries to provide effective, robust and low-cost battlefield sensor systems. The primary applications will be detection and/or classification of ground troops, ground vehicles, airborne vehicles, artillery and sniper. TG-25 has 3 main objectives: (1) to establish acoustic and seismic standards and data exchange procedures, (2) to compare, analyze, exchange, and develop analytical techniques, computational models and signal processing algorithms, and (3) to plan and conduct joint field experiments. In this paper, we discuss participation in the joint NATO field experiment conducted in France in October 2002. The experiment's goal is to demonstrate interoperability of unattended ground sensors from various participating nations. Results of the experiments will be briefed and discussed. Keywords: TG-25, unattended ground sensor, vehicle tracking

  5. Robust Networking Architecture and Secure Communication Scheme for Heterogeneous Wireless Sensor Networks

    ERIC Educational Resources Information Center

    McNeal, McKenzie, III.

    2012-01-01

    Current networking architectures and communication protocols used for Wireless Sensor Networks (WSNs) have been designed to be energy efficient, low latency, and long network lifetime. One major issue that must be addressed is the security in data communication. Due to the limited capabilities of low cost and small sized sensor nodes, designing…

  6. The Use of Artificial Neural Networks to Estimate Speech Intelligibility from Acoustic Variables: A Preliminary Analysis.

    ERIC Educational Resources Information Center

    Metz, Dale Evan; And Others

    1992-01-01

    A preliminary scheme for estimating the speech intelligibility of hearing-impaired speakers from acoustic parameters, using a computerized artificial neural network to process mathematically the acoustic input variables, is outlined. Tests with 60 hearing-impaired speakers found the scheme to be highly accurate in identifying speakers separated by…

  7. Design of a Thermoacoustic Sensor for Low Intensity Ultrasound Measurements Based on an Artificial Neural Network.

    PubMed

    Xing, Jida; Chen, Jie

    2015-01-01

    In therapeutic ultrasound applications, accurate ultrasound output intensities are crucial because the physiological effects of therapeutic ultrasound are very sensitive to the intensity and duration of these applications. Although radiation force balance is a benchmark technique for measuring ultrasound intensity and power, it is costly, difficult to operate, and compromised by noise vibration. To overcome these limitations, the development of a low-cost, easy to operate, and vibration-resistant alternative device is necessary for rapid ultrasound intensity measurement. Therefore, we proposed and validated a novel two-layer thermoacoustic sensor using an artificial neural network technique to accurately measure low ultrasound intensities between 30 and 120 mW/cm2. The first layer of the sensor design is a cylindrical absorber made of plexiglass, followed by a second layer composed of polyurethane rubber with a high attenuation coefficient to absorb extra ultrasound energy. The sensor determined ultrasound intensities according to a temperature elevation induced by heat converted from incident acoustic energy. Compared with our previous one-layer sensor design, the new two-layer sensor enhanced the ultrasound absorption efficiency to provide more rapid and reliable measurements. Using a three-dimensional model in the K-wave toolbox, our simulation of the ultrasound propagation process demonstrated that the two-layer design is more efficient than the single layer design. We also integrated an artificial neural network algorithm to compensate for the large measurement offset. After obtaining multiple parameters of the sensor characteristics through calibration, the artificial neural network is built to correct temperature drifts and increase the reliability of our thermoacoustic measurements through iterative training about ten seconds. The performance of the artificial neural network method was validated through a series of experiments. Compared to our previous

  8. Design of a Thermoacoustic Sensor for Low Intensity Ultrasound Measurements Based on an Artificial Neural Network.

    PubMed

    Xing, Jida; Chen, Jie

    2015-06-23

    In therapeutic ultrasound applications, accurate ultrasound output intensities are crucial because the physiological effects of therapeutic ultrasound are very sensitive to the intensity and duration of these applications. Although radiation force balance is a benchmark technique for measuring ultrasound intensity and power, it is costly, difficult to operate, and compromised by noise vibration. To overcome these limitations, the development of a low-cost, easy to operate, and vibration-resistant alternative device is necessary for rapid ultrasound intensity measurement. Therefore, we proposed and validated a novel two-layer thermoacoustic sensor using an artificial neural network technique to accurately measure low ultrasound intensities between 30 and 120 mW/cm2. The first layer of the sensor design is a cylindrical absorber made of plexiglass, followed by a second layer composed of polyurethane rubber with a high attenuation coefficient to absorb extra ultrasound energy. The sensor determined ultrasound intensities according to a temperature elevation induced by heat converted from incident acoustic energy. Compared with our previous one-layer sensor design, the new two-layer sensor enhanced the ultrasound absorption efficiency to provide more rapid and reliable measurements. Using a three-dimensional model in the K-wave toolbox, our simulation of the ultrasound propagation process demonstrated that the two-layer design is more efficient than the single layer design. We also integrated an artificial neural network algorithm to compensate for the large measurement offset. After obtaining multiple parameters of the sensor characteristics through calibration, the artificial neural network is built to correct temperature drifts and increase the reliability of our thermoacoustic measurements through iterative training about ten seconds. The performance of the artificial neural network method was validated through a series of experiments. Compared to our previous

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

    NASA Astrophysics Data System (ADS)

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

    2005-03-01

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

  10. A Wireless Seismoacoustic Sensor Network for Monitoring Activity at Volcano Reventador, Ecuador

    NASA Astrophysics Data System (ADS)

    Welsh, M.; Werner-Allen, G.; Lorincz, K.; Marcillo, O.; Ruiz, M.; Johnson, J.; Lees, J. M.

    2005-12-01

    We developed a wireless sensor network for monitoring seismoacoustic activity at Volcano Reventador, Ecuador. Wireless sensor networks are a new technology and our group is among the first to apply them to monitoring volcanoes. The small size, low power, and wireless communication capabilities can greatly simplify deployments of large sensor arrays. The network consisted of 16 wireless sensor nodes, each outfitted with an 8 MHz CPU (TI MSP430) and a 2.4 GHz IEEE 802.15.4 radio (Chipcon CC2420) with data rates up to 80 Kbps. Each node acquired acoustic and seismic data at 24-bit resolution, with a microphone and either a single-axis geophone or triaxial short-period seismometer. Each node is powered by two D-cell batteries with a lifetime of about 1 week, and measures 18 x 10 x 8 cm. Nodes were distributed radially from the vent over a 3 km aperture. Control and data messages are relayed via radio to a base station node, with inter-node distances of up to 420 m. The base station transmits data using a FreeWave radio modem, via a repeater, to a laptop located 4 km from the deployment site. Each node samples continuous sensor data and a simple event-detection algorithm is used to trigger data collection. When a sensor detects an event, it relays a short message to the base station via radio. If several nodes report an event within a short time interval, the last 60 seconds of data is downloaded from each node in turn. One of the sensor nodes is programmed to transmit continuous data; due to limited radio bandwidth, it is not possible to collect continuous data from all nodes in the array. A GPS receiver and time synchronization protocol is used to establish a global timebase across all sensor nodes.

  11. Study of data fusion algorithms applied to unattended ground sensor network

    NASA Astrophysics Data System (ADS)

    Pannetier, B.; Moras, J.; Dezert, Jean; Sella, G.

    2014-06-01

    In this paper, data obtained from wireless unattended ground sensor network are used for tracking multiple ground targets (vehicles, pedestrians and animals) moving on and off the road network. The goal of the study is to evaluate several data fusion algorithms to select the best approach to establish the tactical situational awareness. The ground sensor network is composed of heterogeneous sensors (optronic, radar, seismic, acoustic, magnetic sensors) and data fusion nodes. The fusion nodes are small hardware platforms placed on the surveillance area that communicate together. In order to satisfy operational needs and the limited communication bandwidth between the nodes, we study several data fusion algorithms to track and classify targets in real time. A multiple targets tracking (MTT) algorithm is integrated in each data fusion node taking into account embedded constraint. The choice of the MTT algorithm is motivated by the limit of the chosen technology. In the fusion nodes, the distributed MTT algorithm exploits the road network information in order to constrain the multiple dynamic models. Then, a variable structure interacting multiple model (VS-IMM) is adapted with the road network topology. This algorithm is well-known in centralized architecture, but it implies a modification of other data fusion algorithms to preserve the performances of the tracking under constraints. Based on such VS-IMM MTT algorithm, we adapt classical data fusion techniques to make it working in three architectures: centralized, distributed and hierarchical. The sensors measurements are considered asynchronous, but the fusion steps are synchronized on all sensors. Performances of data fusion algorithms are evaluated using simulated data and also validated on real data. The scenarios under analysis contain multiple targets with close and crossing trajectories involving data association uncertainties.

  12. A wireless demodulation system for passive surface acoustic wave torque sensor

    NASA Astrophysics Data System (ADS)

    Ji, Xiaojun; Fan, Yanping; Qi, Hongli; Chen, Jing; Han, Tao; Cai, Ping

    2014-12-01

    Surface acoustic wave (SAW) resonators are utilized as torque sensors for their passive and wireless features. However, the response of a SAW torque sensor is difficult to detect because of the transient response duration and interruption of channel noise, which limit the application of SAW torque sensors. The sensitive mechanism and response function of a passive wireless SAW torque sensor are analyzed in this study. A novel demodulation system involving both hardware and software is developed for the SAW torque sensor. A clipping amplifier is utilized in the hardware to widen the dynamic response range and increase the length of the valid signal. Correlation extension and centroid algorithms are designed to lengthen the received signal and improve the estimation accuracy of the center frequency of the response signal, respectively. Meanwhile, a fast binary search algorithm is proposed to accelerate the scanning cycle according to the developed response function. Finally, the SAW torque sensor demodulation system is set up and SAW resonators with high sensitivity are fabricated on a quartz substrate. The presented demodulation system is tested, and a standard deviation of 0.28 kHz is achieved. This value is much smaller than that of classic and modern spectrum estimation methods. The sensitivity of resonance frequency shift versus torque on the shaft of the assembled senor is 2.03 kHz/Nm; the coefficient of determination is 0.999, and the linearity is 0.87%. Experimental results verify the validity and feasibility of the proposed SAW torque sensor demodulation system.

  13. AEGIS: A Lightweight Firewall for Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Hossain, Mohammad Sajjad; Raghunathan, Vijay

    Firewalls are an essential component in today's networked computing systems (desktops, laptops, and servers) and provide effective protection against a variety of over-the-network security attacks. With the development of technologies such as IPv6 and 6LoWPAN that pave the way for Internet-connected embedded systems and sensor networks, these devices will soon be subject to (and need to be defended against) similar security threats. As a first step, this paper presents Aegis, a lightweight, rule-based firewall for networked embedded systems such as wireless sensor networks. Aegis is based on a semantically rich, yet simple, rule definition language. In addition, Aegis is highly efficient during operation, runs in a transparent manner from running applications, and is easy to maintain. Experimental results obtained using real sensor nodes and cycle-accurate simulations demonstrate that Aegis successfully performs gatekeeping of a sensor node's communication traffic in a flexible manner with minimal overheads.

  14. Mobility in free-space optics based wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Ghosh, Anjan K.; Verma, Pramode; Huck, Robert C.

    2009-05-01

    This paper proposes an FSO-based mobile sensor network that is not subject to RF interference common to wireless sensor networks. FSO-based mobile sensor networks can potentially be used in a battlefield where security of communication, including freedom from susceptibility to enemy-induced jamming, is important. The paper discusses the design of nodes containing multiple transceivers composed of LEDs and photo detectors. Results of initial experiments are included. The work reported in this paper is part of an ongoing investigation on mobile FSO networks, including the design of efficient protocols that can allow the mobile sensor nodes to function as a mesh network permitting information exchange among nodes directly and, possibly, through an intermediate node.

  15. Feasibility study of complex wavefield retrieval in off-axis acoustic holography employing an acousto-optic sensor

    PubMed Central

    Rodríguez, Guillermo López; Weber, Joshua; Sandhu, Jaswinder Singh; Anastasio, Mark A.

    2011-01-01

    We propose and experimentally demonstrate a new method for complex-valued wavefield retrieval in off-axis acoustic holography. The method involves use of an intensity-sensitive acousto-optic (AO) sensor, optimized for use at 3.3 MHz, to record the acoustic hologram and a computational method for reconstruction of the object wavefield. The proposed method may circumvent limitations of conventional implementations of acoustic holography and may facilitate the development of acoustic-holography-based biomedical imaging methods. PMID:21669451

  16. A Mobile Sensor Network System for Monitoring of Unfriendly Environments

    PubMed Central

    Song, Guangming; Zhou, Yaoxin; Ding, Fei; Song, Aiguo

    2008-01-01

    Observing microclimate changes is one of the most popular applications of wireless sensor networks. However, some target environments are often too dangerous or inaccessible to humans or large robots and there are many challenges for deploying and maintaining wireless sensor networks in those unfriendly environments. This paper presents a mobile sensor network system for solving this problem. The system architecture, the mobile node design, the basic behaviors and advanced network capabilities have been investigated respectively. A wheel-based robotic node architecture is proposed here that can add controlled mobility to wireless sensor networks. A testbed including some prototype nodes has also been created for validating the basic functions of the proposed mobile sensor network system. Motion performance tests have been done to get the positioning errors and power consumption model of the mobile nodes. Results of the autonomous deployment experiment show that the mobile nodes can be distributed evenly into the previously unknown environments. It provides powerful support for network deployment and maintenance and can ensure that the sensor network will work properly in unfriendly environments.

  17. Algorithm for heart rate extraction in a novel wearable acoustic sensor.

    PubMed

    Chen, Guangwei; Imtiaz, Syed Anas; Aguilar-Pelaez, Eduardo; Rodriguez-Villegas, Esther

    2015-02-01

    Phonocardiography is a widely used method of listening to the heart sounds and indicating the presence of cardiac abnormalities. Each heart cycle consists of two major sounds - S1 and S2 - that can be used to determine the heart rate. The conventional method of acoustic signal acquisition involves placing the sound sensor at the chest where this sound is most audible. Presented is a novel algorithm for the detection of S1 and S2 heart sounds and the use of them to extract the heart rate from signals acquired by a small sensor placed at the neck. This algorithm achieves an accuracy of 90.73 and 90.69%, with respect to heart rate value provided by two commercial devices, evaluated on more than 38 h of data acquired from ten different subjects during sleep in a pilot clinical study. This is the largest dataset for acoustic heart sound classification and heart rate extraction in the literature to date. The algorithm in this study used signals from a sensor designed to monitor breathing. This shows that the same sensor and signal can be used to monitor both breathing and heart rate, making it highly useful for long-term wearable vital signs monitoring.

  18. Passive wireless surface acoustic wave sensors for monitoring sequestration sites CO2 emission

    SciTech Connect

    Wang, Yizhong; Chyu, Minking; Wang, Qing-Ming

    2013-02-14

    University of Pittsburgh’s Transducer lab has teamed with the U.S. Department of Energy’s National Energy Technology Laboratory (DOE NETL) to conduct a comprehensive study to develop/evaluate low-cost, efficient CO2 measuring technologies for geological sequestration sites leakage monitoring. A passive wireless CO2 sensing system based on surface acoustic wave technology and carbon nanotube nanocomposite was developed. Surface acoustic wave device was studied to determine the optimum parameters. Delay line structure was adopted as basic sensor structure. CNT polymer nanocomposite was fabricated and tested under different temperature and strain condition for natural environment impact evaluation. Nanocomposite resistance increased for 5 times under pure strain, while the temperature dependence of resistance for CNT solely was -1375ppm/°C. The overall effect of temperature on nanocomposite resistance was -1000ppm/°C. The gas response of the nanocomposite was about 10% resistance increase under pure CO2 . The sensor frequency change was around 300ppm for pure CO2 . With paralyne packaging, the sensor frequency change from relative humidity of 0% to 100% at room temperature decreased from over 1000ppm to less than 100ppm. The lowest detection limit of the sensor is 1% gas concentration, with 36ppm frequency change. Wireless module was tested and showed over one foot transmission distance at preferred parallel orientation.

  19. Research progress in the key device and technology for fiber optic sensor network

    NASA Astrophysics Data System (ADS)

    Liu, Deming; Sun, Qizhen; Lu, Ping; Xia, Li; Sima, Chaotan

    2016-03-01

    The recent research progress in the key device and technology of the fiber optic sensor network (FOSN) is introduced in this paper. An architecture of the sensor optical passive network (SPON), by employing hybrid wavelength division multiplexing/time division multiplexing (WDM/TDM) techniques similar to the fiber communication passive optical network (PON), is proposed. The network topology scheme of a hybrid TDM/WDM/FDM (frequency division multiplexing) three-dimension fiber optic sensing system for achieving ultra-large capacity, long distance, and high resolution sensing performance is performed and analyzed. As the most important device of the FOSN, several kinds of light source are developed, including the wideband multi-wavelength fiber laser operating at C band, switchable and tunable 2 μm multi-wavelength fiber lasers, ultra-fast mode-locked fiber laser, as well as the optical wideband chaos source, which have very good application prospects in the FOSN. Meanwhile, intelligent management techniques for the FOSN including wideband spectrum demodulation of the sensing signals and real-time fault monitoring of fiber links are presented. Moreover, several typical applications of the FOSN are also discussed, such as the fiber optic gas sensing network, fiber optic acoustic sensing network, and strain/dynamic strain sensing network.

  20. Composite nanowire networks for biological sensor platforms

    NASA Astrophysics Data System (ADS)

    Jabal, Jamie Marie Francisco

    The main goal of this research is to design, fabricate, and test a nanomaterial-based platform adequate for the measurement of physiological changes in living cells. The two primary objectives toward this end are (1) the synthesis and selection of a suitable nanomaterial and (2) the demonstration of cellular response to a direct stimulus. Determining a useful nanomaterial morphology and behavior within a sensor configuration presented challenges based on cellular integration and access to electrochemical characterization. The prospect for feasible optimization and eventual scale-up in technology were also significant. Constraining criteria are that the nanomaterial detector must (a) be cheap and relatively easy to fabricate controllably, (b) encourage cell attachment, (c) exhibit consistent wettability over time, and (d) facilitate electrochemical processes. The ultimate goal would be to transfer a proof-of-principle and proof-of-design for a whole-cell sensor technology that is cost effective and has a potential for hand-held packaging. Initial tasks were to determine an effective and highly-functional nanomaterial for biosensors by assessing wettability, morphology and conductivity behavior of several candidate materials: gallium nitride nanowires, silicon dioxide nanosprings and nanowires, and titania nanofibers. Electrospinning poly(vinyl pyrrolidone)-coated titania nano- and microfibers (O20 nm--2 microm) into a pseudo-random network is controllable to a uniformity of 1--2° in contact angle. The final electrode can be prepared with a precise wettability ranging from partial wetting to ultrahydrophobic (170°) on a variety of substrates: glass, indium tin oxide, silicon, and aluminum. Fiber mats exhibit excellent mechanical stability against rinsing, and support the incubation of epithelial (skin) and pancreatic cells. Impedance spectroscopy on the whole-cell sensor shows resistive changes attributed to cell growth as well as complex frequency

  1. A Survey on Virtualization of Wireless Sensor Networks

    PubMed Central

    Islam, Md. Motaharul; Hassan, Mohammad Mehedi; Lee, Ga-Won; Huh, Eui-Nam

    2012-01-01

    Wireless Sensor Networks (WSNs) are gaining tremendous importance thanks to their broad range of commercial applications such as in smart home automation, health-care and industrial automation. In these applications multi-vendor and heterogeneous sensor nodes are deployed. Due to strict administrative control over the specific WSN domains, communication barriers, conflicting goals and the economic interests of different WSN sensor node vendors, it is difficult to introduce a large scale federated WSN. By allowing heterogeneous sensor nodes in WSNs to coexist on a shared physical sensor substrate, virtualization in sensor network may provide flexibility, cost effective solutions, promote diversity, ensure security and increase manageability. This paper surveys the novel approach of using the large scale federated WSN resources in a sensor virtualization environment. Our focus in this paper is to introduce a few design goals, the challenges and opportunities of research in the field of sensor network virtualization as well as to illustrate a current status of research in this field. This paper also presents a wide array of state-of-the art projects related to sensor network virtualization. PMID:22438759

  2. A survey on virtualization of Wireless Sensor Networks.

    PubMed

    Islam, Md Motaharul; Hassan, Mohammad Mehedi; Lee, Ga-Won; Huh, Eui-Nam

    2012-01-01

    Wireless Sensor Networks (WSNs) are gaining tremendous importance thanks to their broad range of commercial applications such as in smart home automation, health-care and industrial automation. In these applications multi-vendor and heterogeneous sensor nodes are deployed. Due to strict administrative control over the specific WSN domains, communication barriers, conflicting goals and the economic interests of different WSN sensor node vendors, it is difficult to introduce a large scale federated WSN. By allowing heterogeneous sensor nodes in WSNs to coexist on a shared physical sensor substrate, virtualization in sensor network may provide flexibility, cost effective solutions, promote diversity, ensure security and increase manageability. This paper surveys the novel approach of using the large scale federated WSN resources in a sensor virtualization environment. Our focus in this paper is to introduce a few design goals, the challenges and opportunities of research in the field of sensor network virtualization as well as to illustrate a current status of research in this field. This paper also presents a wide array of state-of-the art projects related to sensor network virtualization. PMID:22438759

  3. A survey on virtualization of Wireless Sensor Networks.

    PubMed

    Islam, Md Motaharul; Hassan, Mohammad Mehedi; Lee, Ga-Won; Huh, Eui-Nam

    2012-01-01

    Wireless Sensor Networks (WSNs) are gaining tremendous importance thanks to their broad range of commercial applications such as in smart home automation, health-care and industrial automation. In these applications multi-vendor and heterogeneous sensor nodes are deployed. Due to strict administrative control over the specific WSN domains, communication barriers, conflicting goals and the economic interests of different WSN sensor node vendors, it is difficult to introduce a large scale federated WSN. By allowing heterogeneous sensor nodes in WSNs to coexist on a shared physical sensor substrate, virtualization in sensor network may provide flexibility, cost effective solutions, promote diversity, ensure security and increase manageability. This paper surveys the novel approach of using the large scale federated WSN resources in a sensor virtualization environment. Our focus in this paper is to introduce a few design goals, the challenges and opportunities of research in the field of sensor network virtualization as well as to illustrate a current status of research in this field. This paper also presents a wide array of state-of-the art projects related to sensor network virtualization.

  4. Provenance-Enabled Integration of Sensor Network Data

    NASA Astrophysics Data System (ADS)

    Pinheiro da Silva, P.; McGuinness, D. L.

    2014-12-01

    Ontology design in support of sensor networks requires deep scientific and technical knowledge. For instance, sensor network ontologies may define concepts rich enough to describe the selection of sensor locations that are driven by both scientific use cases, such as proximity to a physical entity, and technical requirements, such as wireless coverage. Our work in collaboration with IBM and the FUND for Lake George is set within the context of the Jefferson Project that aims to monitor, analyze, and understand observation and simulation data in support of decision making concerning the ecosystem of Lake George, NY. We have designed a Human-Aware Sensor Network Ontology (HASNet-O) that we believe is broadly reusable. We will highlight its contributions, describe its relationships to well used ontologies, and demonstrate it in action in the Jefferson Project. The ontology leverages best in class foundational ontologies including OBOE, VSTO, and PROV. One of the reasons HASNet-O is reusable is because it uses a provenance perspective to generalize what initially looked like sensor-specific terms that can be more accurately viewed as provenance terms. For example, we observe that the Activity concept from the PROV language, a W3C provenance standard, can be used to explain complete sensor lifecycles by describing how a network operates including how human interventions may interfere with the quality of the sensor network data, even for highly automated networks. We further observe that Observation activities, which are at the core of most sensor network ontologies, are not described in terms of deployments. In fact, Deployment activities are rarely documented in sensor data/metadata although Observation instances can only occur during the lifetime of Deployment instances. Our analysis of network ontologies in light of provenance knowledge includes a discussion about relationships. For instance, relationships between sensors and data are well-established provenance

  5. Bio-Inspired Stretchable Absolute Pressure Sensor Network.

    PubMed

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

    2016-01-02

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

  6. Bio-Inspired Stretchable Absolute Pressure Sensor Network

    PubMed Central

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

    2016-01-01

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

  7. Bio-Inspired Stretchable Absolute Pressure Sensor Network.

    PubMed

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

    2016-01-01

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

  8. Implementation of Surface Acoustic Wave Vapor Sensor Using Complementary Metal-Oxide-Semiconductor Amplifiers

    NASA Astrophysics Data System (ADS)

    Chiu, Chia-Sung; Chang, Ching-Chun; Ku, Chia-Lin; Peng, Kang-Ming; Jeng, Erik S.; Chen, Wen-Lin; Huang, Guo-Wei; Wu, Lin-Kun

    2009-04-01

    A surface acoustic wave (SAW) vapor sensor is presented in this work. A SAW delay line oscillator on quartz substrate with the high gain complementary metal-oxide-semiconductor (CMOS) amplifier using a two-poly-two-metal (2P2M) 0.35 µm process was designed. The gain of the CMOS amplifier and its total power consumption are 20 dB and 70 mW, respectively. The achieved phase noise of this SAW oscillator is -150 dBc/Hz at 100 kHz offset. The sensing is successfully demonstrated by a thin poly(epichlorohydrin) (PECH) polymer film on a SAW oscillator with alcohol vapor. This two-in-one sensor unit includes the SAW device and the CMOS amplifier provides designers with comprehensive model for using these components for sensor circuit fabrication. Furthermore it will be promising for future chemical and biological sensing applications.

  9. Response mechanism for surface acoustic wave gas sensors based on surface-adsorption.

    PubMed

    Liu, Jiansheng; Lu, Yanyan

    2014-04-16

    A theoretical model is established to describe the response mechanism of surface acoustic wave (SAW) gas sensors based on physical adsorption on the detector surface. Wohljent's method is utilized to describe the relationship of sensor output (frequency shift of SAW oscillator) and the mass loaded on the detector surface. The Brunauer-Emmett-Teller (BET) formula and its improved form are introduced to depict the adsorption behavior of gas on the detector surface. By combining the two methods, we obtain a theoretical model for the response mechanism of SAW gas sensors. By using a commercial SAW gas chromatography (GC) analyzer, an experiment is performed to measure the frequency shifts caused by different concentration of dimethyl methylphosphonate (DMMP). The parameters in the model are given by fitting the experimental results and the theoretical curve agrees well with the experimental data.

  10. CMOS: Efficient Clustered Data Monitoring in Sensor Networks

    PubMed Central

    2013-01-01

    Tiny and smart sensors enable applications that access a network of hundreds or thousands of sensors. Thus, recently, many researchers have paid attention to wireless sensor networks (WSNs). The limitation of energy is critical since most sensors are battery-powered and it is very difficult to replace batteries in cases that sensor networks are utilized outdoors. Data transmission between sensor nodes needs more energy than computation in a sensor node. In order to reduce the energy consumption of sensors, we present an approximate data gathering technique, called CMOS, based on the Kalman filter. The goal of CMOS is to efficiently obtain the sensor readings within a certain error bound. In our approach, spatially close sensors are grouped as a cluster. Since a cluster header generates approximate readings of member nodes, a user query can be answered efficiently using the cluster headers. In addition, we suggest an energy efficient clustering method to distribute the energy consumption of cluster headers. Our simulation results with synthetic data demonstrate the efficiency and accuracy of our proposed technique. PMID:24459444

  11. Collaborative Supervised Learning for Sensor Networks

    NASA Technical Reports Server (NTRS)

    Wagstaff, Kiri L.; Rebbapragada, Umaa; Lane, Terran

    2011-01-01

    Collaboration methods for distributed machine-learning algorithms involve the specification of communication protocols for the learners, which can query other learners and/or broadcast their findings preemptively. Each learner incorporates information from its neighbors into its own training set, and they are thereby able to bootstrap each other to higher performance. Each learner resides at a different node in the sensor network and makes observations (collects data) independently of the other learners. After being seeded with an initial labeled training set, each learner proceeds to learn in an iterative fashion. New data is collected and classified. The learner can then either broadcast its most confident classifications for use by other learners, or can query neighbors for their classifications of its least confident items. As such, collaborative learning combines elements of both passive (broadcast) and active (query) learning. It also uses ideas from ensemble learning to combine the multiple responses to a given query into a single useful label. This approach has been evaluated against current non-collaborative alternatives, including training a single classifier and deploying it at all nodes with no further learning possible, and permitting learners to learn from their own most confident judgments, absent interaction with their neighbors. On several data sets, it has been consistently found that active collaboration is the best strategy for a distributed learner network. The main advantages include the ability for learning to take place autonomously by collaboration rather than by requiring intervention from an oracle (usually human), and also the ability to learn in a distributed environment, permitting decisions to be made in situ and to yield faster response time.

  12. Melatonin action in a midbrain vocal-acoustic network

    PubMed Central

    Feng, Ni Y.; Bass, Andrew H.

    2014-01-01

    Melatonin is a well-documented time-keeping hormone that can entrain an individual's physiology and behavior to the day–night cycle, though surprisingly little is known about its influence on the neural basis of social behavior, including vocalization. Male midshipman fish (Porichthys notatus) produce several call types distinguishable by duration and by daily and seasonal cycles in their production. We investigated melatonin's influence on the known nocturnal- and breeding season-dependent increase in excitability of the midshipman's vocal network (VN) that directly patterns natural calls. VN output is readily recorded from the vocal nerve as a ‘fictive call’. Five days of constant light significantly increased stimulus threshold levels for calls electrically evoked from vocally active sites in the medial midbrain, supporting previous findings that light suppresses VN excitability, while 2-iodomelatonin (2-IMel; a melatonin analog) implantation decreased threshold. 2-IMel also increased fictive call duration evoked from medial sites as well as lateral midbrain sites that produced several-fold longer calls irrespective of photoregime or drug treatment. When stimulus intensity was incrementally increased, 2-IMel increased duration only at lateral sites, suggesting that melatonin action is stronger in the lateral midbrain. For animals receiving 5 days of constant darkness, known to increase VN excitability, systemic injections of either of two mammalian melatonin receptor antagonists increased threshold and decreased duration for calls evoked from medial sites. Our results demonstrate melatonin modulation of VN excitability and suggest that social context-dependent call types differing in duration may be determined by neuro-hormonal action within specific regions of a midbrain vocal-acoustic network. PMID:24265429

  13. Energy Efficient Cluster Based Scheduling Scheme for Wireless Sensor Networks

    PubMed Central

    Srie Vidhya Janani, E.; Ganesh Kumar, P.

    2015-01-01

    The energy utilization of sensor nodes in large scale wireless sensor network points out the crucial need for scalable and energy efficient clustering protocols. Since sensor nodes usually operate on batteries, the maximum utility of network is greatly dependent on ideal usage of energy leftover in these sensor nodes. In this paper, we propose an Energy Efficient Cluster Based Scheduling Scheme for wireless sensor networks that balances the sensor network lifetime and energy efficiency. In the first phase of our proposed scheme, cluster topology is discovered and cluster head is chosen based on remaining energy level. The cluster head monitors the network energy threshold value to identify the energy drain rate of all its cluster members. In the second phase, scheduling algorithm is presented to allocate time slots to cluster member data packets. Here congestion occurrence is totally avoided. In the third phase, energy consumption model is proposed to maintain maximum residual energy level across the network. Moreover, we also propose a new packet format which is given to all cluster member nodes. The simulation results prove that the proposed scheme greatly contributes to maximum network lifetime, high energy, reduced overhead, and maximum delivery ratio. PMID:26495417

  14. Naming, location tracking, synchronizing, and aggregating wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Bijoy, Rajathilagam; Jayaraj, Br.; Rangan, P. Venkat

    2005-11-01

    The growth in utilization of sensor networks in every field of science has compelled the research community to device a common addressing technique for sensor networks. To achieve this, we propose an addressing and naming scheme for sensors based on a hierarchical model of the sensor network in this paper. We show that, the complete scheme allows accessing and tracking sensor devices by names and inherently facilitates data aggregation. We study the performance of and optimize the hierarchical architecture and use algorithms for bounding timing delays, width and height. Finally, we suggest a gateway-based architecture to establish a secure layer above the routing protocol to perform safe communication and location tracking. From our analysis it is seen that the methodology can be adopted for various scenarios like disaster areas, habitat monitoring, target tracking, medical monitoring, battlefield, etc.

  15. Geographic wormhole detection in wireless sensor networks.

    PubMed

    Sookhak, Mehdi; Akhundzada, Adnan; Sookhak, Alireza; Eslaminejad, Mohammadreza; Gani, Abdullah; Khurram Khan, Muhammad; Li, Xiong; Wang, Xiaomin

    2015-01-01

    Wireless sensor networks (WSNs) are ubiquitous and pervasive, and therefore; highly susceptible to a number of security attacks. Denial of Service (DoS) attack is considered the most dominant and a major threat to WSNs. Moreover, the wormhole attack represents one of the potential forms of the Denial of Service (DoS) attack. Besides, crafting the wormhole attack is comparatively simple; though, its detection is nontrivial. On the contrary, the extant wormhole defense methods need both specialized hardware and strong assumptions to defend against static and dynamic wormhole attack. The ensuing paper introduces a novel scheme to detect wormhole attacks in a geographic routing protocol (DWGRP). The main contribution of this paper is to detect malicious nodes and select the best and the most reliable neighbors based on pairwise key pre-distribution technique and the beacon packet. Moreover, this novel technique is not subject to any specific assumption, requirement, or specialized hardware, such as a precise synchronized clock. The proposed detection method is validated by comparisons with several related techniques in the literature, such as Received Signal Strength (RSS), Authentication of Nodes Scheme (ANS), Wormhole Detection uses Hound Packet (WHOP), and Wormhole Detection with Neighborhood Information (WDI) using the NS-2 simulator. The analysis of the simulations shows promising results with low False Detection Rate (FDR) in the geographic routing protocols. PMID:25602616

  16. Geographic wormhole detection in wireless sensor networks.

    PubMed

    Sookhak, Mehdi; Akhundzada, Adnan; Sookhak, Alireza; Eslaminejad, Mohammadreza; Gani, Abdullah; Khurram Khan, Muhammad; Li, Xiong; Wang, Xiaomin

    2015-01-01

    Wireless sensor networks (WSNs) are ubiquitous and pervasive, and therefore; highly susceptible to a number of security attacks. Denial of Service (DoS) attack is considered the most dominant and a major threat to WSNs. Moreover, the wormhole attack represents one of the potential forms of the Denial of Service (DoS) attack. Besides, crafting the wormhole attack is comparatively simple; though, its detection is nontrivial. On the contrary, the extant wormhole defense methods need both specialized hardware and strong assumptions to defend against static and dynamic wormhole attack. The ensuing paper introduces a novel scheme to detect wormhole attacks in a geographic routing protocol (DWGRP). The main contribution of this paper is to detect malicious nodes and select the best and the most reliable neighbors based on pairwise key pre-distribution technique and the beacon packet. Moreover, this novel technique is not subject to any specific assumption, requirement, or specialized hardware, such as a precise synchronized clock. The proposed detection method is validated by comparisons with several related techniques in the literature, such as Received Signal Strength (RSS), Authentication of Nodes Scheme (ANS), Wormhole Detection uses Hound Packet (WHOP), and Wormhole Detection with Neighborhood Information (WDI) using the NS-2 simulator. The analysis of the simulations shows promising results with low False Detection Rate (FDR) in the geographic routing protocols.

  17. Geographic Wormhole Detection in Wireless Sensor Networks

    PubMed Central

    Sookhak, Mehdi; Akhundzada, Adnan; Sookhak, Alireza; Eslaminejad, Mohammadreza; Gani, Abdullah; Khurram Khan, Muhammad; Li, Xiong; Wang, Xiaomin

    2015-01-01

    Wireless sensor networks (WSNs) are ubiquitous and pervasive, and therefore; highly susceptible to a number of security attacks. Denial of Service (DoS) attack is considered the most dominant and a major threat to WSNs. Moreover, the wormhole attack represents one of the potential forms of the Denial of Service (DoS) attack. Besides, crafting the wormhole attack is comparatively simple; though, its detection is nontrivial. On the contrary, the extant wormhole defense methods need both specialized hardware and strong assumptions to defend against static and dynamic wormhole attack. The ensuing paper introduces a novel scheme to detect wormhole attacks in a geographic routing protocol (DWGRP). The main contribution of this paper is to detect malicious nodes and select the best and the most reliable neighbors based on pairwise key pre-distribution technique and the beacon packet. Moreover, this novel technique is not subject to any specific assumption, requirement, or specialized hardware, such as a precise synchronized clock. The proposed detection method is validated by comparisons with several related techniques in the literature, such as Received Signal Strength (RSS), Authentication of Nodes Scheme (ANS), Wormhole Detection uses Hound Packet (WHOP), and Wormhole Detection with Neighborhood Information (WDI) using the NS-2 simulator. The analysis of the simulations shows promising results with low False Detection Rate (FDR) in the geographic routing protocols. PMID:25602616

  18. Topology optimisation for energy management in underwater sensor networks

    NASA Astrophysics Data System (ADS)

    Jha, Devesh K.; Wettergren, Thomas A.; Ray, Asok; Mukherjee, Kushal

    2015-09-01

    In general, battery-powered sensors in a sensor network are operable as long as they can communicate sensed data to a processing node. In this context, a sensor network has two competing objectives: (1) maximisation of the network performance with respect to the probability of successful search for a specified upper bound on the probability of false alarms, and (2) maximisation of the network's operable life. As both sensing and communication of data consume battery energy at the sensing nodes of the sensor network, judicious use of sensing power and communication power is needed to improve the lifetime of the sensor network. This paper presents an adaptive energy management policy that will optimally allocate the available energy between sensing and communication at each sensing node to maximise the network performance subject to specified constraints. Under the assumptions of fixed total energy allocation for a sensor network operating for a specified time period, the problem is reduced to synthesis of an optimal network topology that maximises the probability of successful search (of a target) over a surveillance region. In a two-stage optimisation, a genetic algorithm-based meta-heuristic search is first used to efficiently explore the global design space, and then a local pattern search algorithm is used for convergence to an optimal solution. The results of performance optimisation are generated on a simulation test bed to validate the proposed concept. Adaptation to energy variations across the network is shown to be manifested as a change in the optimal network topology by using sensing and communication models for underwater environment. The approximate Pareto-optimal surface is obtained as a trade-off between network lifetime and probability of successful search over the surveillance region.

  19. Intelligent Wireless Sensor Networks for System Health Monitoring

    NASA Technical Reports Server (NTRS)

    Alena, Rick

    2011-01-01

    Wireless sensor networks (WSN) based on the IEEE 802.15.4 Personal Area Network (PAN) standard are finding increasing use in the home automation and emerging smart energy markets. The network and application layers, based on the ZigBee 2007 Standard, provide a convenient framework for component-based software that supports customer solutions from multiple vendors. WSNs provide the inherent fault tolerance required for aerospace applications. The Discovery and Systems Health Group at NASA Ames Research Center has been developing WSN technology for use aboard aircraft and spacecraft for System Health Monitoring of structures and life support systems using funding from the NASA Engineering and Safety Center and Exploration Technology Development and Demonstration Program. This technology provides key advantages for low-power, low-cost ancillary sensing systems particularly across pressure interfaces and in areas where it is difficult to run wires. Intelligence for sensor networks could be defined as the capability of forming dynamic sensor networks, allowing high-level application software to identify and address any sensor that joined the network without the use of any centralized database defining the sensors characteristics. The IEEE 1451 Standard defines methods for the management of intelligent sensor systems and the IEEE 1451.4 section defines Transducer Electronic Datasheets (TEDS), which contain key information regarding the sensor characteristics such as name, description, serial number, calibration information and user information such as location within a vehicle. By locating the TEDS information on the wireless sensor itself and enabling access to this information base from the application software, the application can identify the sensor unambiguously and interpret and present the sensor data stream without reference to any other information. The application software is able to read the status of each sensor module, responding in real-time to changes of

  20. ZigBee wireless sensor network for environmental monitoring system

    NASA Astrophysics Data System (ADS)

    Chai, Shun-qi; Ji, Lei; Wu, Hong

    2009-11-01

    ZigBee is a new close-up, low-complexity, low-power, low data rate, low-cost wireless networking technology, mainly used for short distance wireless transmission. It is based on IEEE802.15.4 standards, thousands of tiny sensors form a network through mutual coordination to communications. This paper introduces the ZigBee wireless sensor networks in environmental monitoring applications. The hardware design, including microprocessor, data acquisition, antenna and peripheral circuits of the chips, and through software design composed ZigBee mesh network that can make data acquisition and communication. This network has low power consumption, low cost, the effective area is big, and information transfers reliable merits. And have confirmed the network's communication applicability by the Serial Com Assistant, also testified the network have very good pragmatism by the NS2 emulation the network's operation.

  1. Estimating cetacean population density using fixed passive acoustic sensors: an example with Blainville's beaked whales.

    PubMed

    Marques, Tiago A; Thomas, Len; Ward, Jessica; DiMarzio, Nancy; Tyack, Peter L

    2009-04-01

    Methods are developed for estimating the size/density of cetacean populations using data from a set of fixed passive acoustic sensors. The methods convert the number of detected acoustic cues into animal density by accounting for (i) the probability of detecting cues, (ii) the rate at which animals produce cues, and (iii) the proportion of false positive detections. Additional information is often required for estimation of these quantities, for example, from an acoustic tag applied to a sample of animals. Methods are illustrated with a case study: estimation of Blainville's beaked whale density over a 6 day period in spring 2005, using an 82 hydrophone wide-baseline array located in the Tongue of the Ocean, Bahamas. To estimate the required quantities, additional data are used from digital acoustic tags, attached to five whales over 21 deep dives, where cues recorded on some of the dives are associated with those received on the fixed hydrophones. Estimated density was 25.3 or 22.5 animals/1000 km(2), depending on assumptions about false positive detections, with 95% confidence intervals 17.3-36.9 and 15.4-32.9. These methods are potentially applicable to a wide variety of marine and terrestrial species that are hard to survey using conventional visual methods.

  2. Development of an Acoustic Sensor for On-Line Gas Temperature Measurement in Gasifiers

    SciTech Connect

    Peter Ariessohn; Hans Hornung

    2006-01-15

    This project was awarded under U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL) Program Solicitation DE-PS26-02NT41422 and specifically addresses Technical Topical Area 2-Gasification Technologies. The project team includes Enertechnix, Inc. as the main contractor and ConocoPhillips Company as a technical partner, who also provides access to the SG Solutions Gasification Facility (formerly Wabash River Energy Limited), host for the field-testing portion of the research. Since 1989 the U.S. Department of Energy has supported development of advanced coal gasification technology. The Wabash River and TECO IGCC demonstration projects supported by the DOE have demonstrated the ability of these plants to achieve high levels of energy efficiency and extremely low emissions of hazardous pollutants. However, a continuing challenge for this technology is the tradeoff between high carbon conversion which requires operation with high internal gas temperatures, and limited refractory life which is exacerbated by those high operating temperatures. Attempts to control internal gas temperature so as to operate these gasifiers at the optimum temperature have been hampered by the lack of a reliable technology for measuring internal gas temperatures. Thermocouples have serious survival problems and provide useful temperature information for only a few days or weeks after startup before burning out. For this reason, the Department of Energy has funded several research projects to develop more robust and reliable temperature measurement approaches for use in coal gasifiers. Enertechnix has developed a line of acoustic gas temperature sensors for use in coal-fired electric utility boilers, kraft recovery boilers, cement kilns and petrochemical process heaters. Acoustic pyrometry provides several significant advantages for gas temperature measurement in hostile process environments. First, it is non-intrusive so survival of the measurement components is not a

  3. SensorKit: An End-to-End Solution for Environmental Sensor Networking

    NASA Astrophysics Data System (ADS)

    Silva, F.; Graham, E.; Deschon, A.; Lam, Y.; Goldman, J.; Wroclawski, J.; Kaiser, W.; Benzel, T.

    2008-12-01

    Modern day sensor network technology has shown great promise to transform environmental data collection. However, despite the promise, these systems have remained the purview of the engineers and computer scientists who design them rather than a useful tool for the environmental scientists who need them. SensorKit is conceived of as a way to make wireless sensor networks accessible to The People: it is an advanced, powerful tool for sensor data collection that does not require advanced technological know-how. We are aiming to make wireless sensor networks for environmental science as simple as setting up a standard home computer network by providing simple, tested configurations of commercially-available hardware, free and easy-to-use software, and step-by-step tutorials. We designed and built SensorKit using a simplicity-through-sophistication approach, supplying users a powerful sensor to database end-to-end system with a simple and intuitive user interface. Our objective in building SensorKit was to make the prospect of using environmental sensor networks as simple as possible. We built SensorKit from off the shelf hardware components, using the Compact RIO platform from National Instruments for data acquisition due to its modular architecture and flexibility to support a large number of sensor types. In SensorKit, we support various types of analog, digital and networked sensors. Our modular software architecture allows us to abstract sensor details and provide users a common way to acquire data and to command different types of sensors. SensorKit is built on top of the Sensor Processing and Acquisition Network (SPAN), a modular framework for acquiring data in the field, moving it reliably to the scientist institution, and storing it in an easily-accessible database. SPAN allows real-time access to the data in the field by providing various options for long haul communication, such as cellular and satellite links. Our system also features reliable data storage

  4. Designing Sensor Networks by a Generalized Highly Optimized Tolerance Model

    NASA Astrophysics Data System (ADS)

    Miyano, Takaya; Yamakoshi, Miyuki; Higashino, Sadanori; Tsutsui, Takako

    A variant of the highly optimized tolerance model is applied to a toy problem of bioterrorism to determine the optimal arrangement of hypothetical bio-sensors to avert epidemic outbreak. Nonlinear loss function is utilized in searching the optimal structure of the sensor network. The proposed method successfully averts disastrously large events, which can not be achieved by the original highly optimized tolerance model.

  5. Combine harvester monitor system based on wireless sensor network

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A measurement method based on Wireless Sensor Network (WSN) was developed to monitor the working condition of combine harvester for remote application. Three JN5139 modules were chosen for sensor data acquisition and another two as a router and a coordinator, which could create a tree topology netwo...

  6. Random set tracking and entropy based control applied to distributed sensor networks

    NASA Astrophysics Data System (ADS)

    Stein, David; Witkoskie, James; Theophanis, Stephen; Kuklinski, Walter

    2007-04-01

    This paper describes an integrated approach to sensor fusion and resource management applicable to sensor networks. The sensor fusion and tracking algorithm is based on the theory of random sets. Tracking is herein considered to be the estimation of parameters in a state space such that for a given target certain components, e.g., position and velocity, are time varying and other components, e.g., identifying features, are stationary. The fusion algorithm provides at each time step the posterior probability density function, known as the global density, on the state space, and the control algorithm identifies the set of sensors that should be used at the next time step in order to minimize, subject to constraints, an approximation of the expected entropy of the global density. The random set approach to target tracking models association ambiguity by statistically weighing all possible hypotheses and associations. Computational complexity is managed by approximating the posterior Global Density using a Gaussian mixture density and using an approach based on the Kulbach-Leibler metric to limit the number of components in the Gaussian mixture representation. A closed form approximation of the expected entropy of the global density, expressed as a Gaussian mixture density, at the next time step for a given set of proposed measurements is developed. Optimal sensor selection involves a search over subsets of sensors, and the computational complexity of this search is managed by employing the Mobius transformation. Field and simulated data from a sensor network comprised of multiple range radars, and acoustic arrays, that measure angle of arrival, are used to demonstrate the approach to sensor fusion and resource management.

  7. Real-time method for establishing a detection map for a network of sensors

    SciTech Connect

    Nguyen, Hung D; Koch, Mark W; Giron, Casey; Rondeau, Daniel M; Russell, John L

    2012-09-11

    A method for establishing a detection map of a dynamically configurable sensor network. This method determines an appropriate set of locations for a plurality of sensor units of a sensor network and establishes a detection map for the network of sensors while the network is being set up; the detection map includes the effects of the local terrain and individual sensor performance. Sensor performance is characterized during the placement of the sensor units, which enables dynamic adjustment or reconfiguration of the placement of individual elements of the sensor network during network set-up to accommodate variations in local terrain and individual sensor performance. The reconfiguration of the network during initial set-up to accommodate deviations from idealized individual sensor detection zones improves the effectiveness of the sensor network in detecting activities at a detection perimeter and can provide the desired sensor coverage of an area while minimizing unintentional gaps in coverage.

  8. Research Trends in Wireless Visual Sensor Networks When Exploiting Prioritization

    PubMed Central

    Costa, Daniel G.; Guedes, Luiz Affonso; Vasques, Francisco; Portugal, Paulo

    2015-01-01

    The development of wireless sensor networks for control and monitoring functions has created a vibrant investigation scenario, where many critical topics, such as communication efficiency and energy consumption, have been investigated in the past few years. However, when sensors are endowed with low-power cameras for visual monitoring, a new scope of challenges is raised, demanding new research efforts. In this context, the resource-constrained nature of sensor nodes has demanded the use of prioritization approaches as a practical mechanism to lower the transmission burden of visual data over wireless sensor networks. Many works in recent years have considered local-level prioritization parameters to enhance the overall performance of those networks, but global-level policies can potentially achieve better results in terms of visual monitoring efficiency. In this paper, we make a broad review of some recent works on priority-based optimizations in wireless visual sensor networks. Moreover, we envisage some research trends when exploiting prioritization, potentially fostering the development of promising optimizations for wireless sensor networks composed of visual sensors. PMID:25599425

  9. Acoustic-wave sensor apparatus for analyzing a petroleum-based composition and sensing solidification of constituents therein

    DOEpatents

    Spates, J.J.; Martin, S.J.; Mansure, A.J.

    1997-08-26

    An acoustic-wave sensor apparatus and method are disclosed. The apparatus for analyzing a normally liquid petroleum-based composition includes at least one acoustic-wave device in contact with the petroleum-based composition for sensing or detecting the presence of constituents (e.g. paraffins or petroleum waxes) therein which solidify upon cooling of the petroleum-based composition below a cloud-point temperature. The acoustic-wave device can be a thickness-shear-mode device (also termed a quartz crystal microbalance), a surface-acoustic-wave device, an acoustic-plate-mode device or a flexural plate-wave device. Embodiments of the present invention can be used for measuring a cloud point, a pour point and/or a freeze point of the petroleum-based composition, and for determining a temperature characteristic of each point. Furthermore, measurements with the acoustic-wave sensor apparatus can be made off-line by using a sample having a particular petroleum-based composition; or in-situ with the petroleum-based composition contained within a pipeline or storage tank. The acoustic-wave sensor apparatus has uses in many different petroleum technology areas, including the recovery, transport, storage, refining and use of petroleum and petroleum-based products. 7 figs.

  10. Acoustic-wave sensor apparatus for analyzing a petroleum-based composition and sensing solidification of constituents therein

    DOEpatents

    Spates, James J.; Martin, Stephen J.; Mansure, Arthur J.

    1997-01-01

    An acoustic-wave sensor apparatus and method. The apparatus for analyzing a normally liquid petroleum-based composition includes at least one acoustic-wave device in contact with the petroleum-based composition for sensing or detecting the presence of constituents (e.g. paraffins or petroleum waxes) therein which solidify upon cooling of the petroleum-based composition below a cloud-point temperature. The acoustic-wave device can be a thickness-shear-mode device (also termed a quartz crystal mircrobalance), a surface-acoustic-wave device, an acoustic-plate-mode device or a flexural plate-wave device. Embodiments of the present invention can be used for measuring a cloud point, a pour point and/or a freeze point of the petroleum-based composition, and for determining a temperature characteristic of each point. Furthermore, measurements with the acoustic-wave sensor apparatus can be made off-line by using a sample having a particular petroleum-based composition; or in-situ with the petroleum-based composition contained within a pipeline or storage tank. The acoustic-wave sensor apparatus has uses in many different petroleum technology areas, including the recover transport, storage, refining and use of petroleum and petroleum-based products.

  11. The application of Shuffled Frog Leaping Algorithm to Wavelet Neural Networks for acoustic emission source location

    NASA Astrophysics Data System (ADS)

    Cheng, Xinmin; Zhang, Xiaodan; Zhao, Li; Deng, Aideng; Bao, Yongqiang; Liu, Yong; Jiang, Yunliang

    2014-04-01

    When using acoustic emission to locate the friction fault source of rotating machinery, the effects of strong noise and waveform distortion make accurate locating difficult. Applying neural network for acoustic emission source location could be helpful. In the BP Wavelet Neural Network, BP is a local search algorithm, which falls into local minimum easily. The probability of successful search is low. We used Shuffled Frog Leaping Algorithm (SFLA) to optimize the parameters of the Wavelet Neural Network, and the optimized Wavelet Neural Network to locate the source. After having performed the experiments of friction acoustic emission's source location on the rotor friction test machine, the results show that the calculation of SFLA is simple and effective, and that locating is accurate with proper structure of the network and input parameters.

  12. OGC standards for end-to-end sensor network integration

    NASA Astrophysics Data System (ADS)

    Headley, K. L.; Broering, A.; O'Reilly, T. C.; Toma, D.; Del Rio, J.; Bermudez, L. E.; Zedlitz, J.; Johnson, G.; Edgington, D.

    2010-12-01

    Many sensor networks have been deployed to monitor Earth's environment, and more are planned for the future. Environmental sensors have continuously improved by becoming smaller, cheaper, more intelligent, and more reliable. But due to the large number of sensor manufacturers and accompanying protocols, integrating diverse sensors into observing systems is not straightforward, requiring development of driver software and manual tedious configuration. Use of standard protocols and formats can improve and automate the process of sensor installation, operation, and data processing. The Open Geospatial Consortium's Sensor Web Enablement (SWE) initiative defines standards which make sensors available over the Web through standardized formats and Web Service interfaces by hiding the heterogeneity of sensor protocols from the application layer. Current SWE standards do not deal with actual sensor protocols, and the connection between sensors and SWE services is usually established by manually adapting the internals of the SWE service implementation to the specific sensor interface. Such sensor "drivers" have to be built for each kind of sensor interface, which leads to extensive efforts in developing large-scale systems. To tackle this issue we have developed a model for Sensor Interface Descriptors (SID) which enables the declarative description of sensor interfaces, including the definition of the communication protocol, sensor commands, processing steps and metadata association. The model is designed as a profile and extension of OGC SWE's Sensor Model Language standard. In this model, a SID is defined in XML for each kind of sensor protocol. SID instances for particular sensor types can be reused in different scenarios and can be shared among user communities. A SID interpreter can be built which translates between various sensor protocols and SWE protocols, hence closing the described interoperability gap. The SID interpreter is independent of any particular sensor

  13. Optimization of Capacitive Acoustic Resonant Sensor Using Numerical Simulation and Design of Experiment

    PubMed Central

    Haque, Rubaiyet Iftekharul; Loussert, Christophe; Sergent, Michelle; Benaben, Patrick; Boddaert, Xavier

    2015-01-01

    Optimization of the acoustic resonant sensor requires a clear understanding of how the output responses of the sensor are affected by the variation of different factors. During this work, output responses of a capacitive acoustic transducer, such as membrane displacement, quality factor, and capacitance variation, are considered to evaluate the sensor design. The six device parameters taken into consideration are membrane radius, backplate radius, cavity height, air gap, membrane tension, and membrane thickness. The effects of factors on the output responses of the transducer are investigated using an integrated methodology that combines numerical simulation and design of experiments (DOE). A series of numerical experiments are conducted to obtain output responses for different combinations of device parameters using finite element methods (FEM). Response surface method is used to identify the significant factors and to develop the empirical models for the output responses. Finally, these results are utilized to calculate the optimum device parameters using multi-criteria optimization with desirability function. Thereafter, the validating experiments are designed and deployed using the numerical simulation to crosscheck the responses. PMID:25894937

  14. Investigation of phononic crystals for dispersive surface acoustic wave ozone sensors

    NASA Astrophysics Data System (ADS)

    Westafer, Ryan S.

    The object of this research was to investigate dispersion in surface phononic crystals (PnCs) for application to a newly developed passive surface acoustic wave (SAW) ozone sensor. Frequency band gaps and slow sound already have been reported for PnC lattice structures. Such engineered structures are often advertised to reduce loss, increase sensitivity, and reduce device size. However, these advances have not yet been realized in the context of surface acoustic wave sensors. In early work, we computed SAW dispersion in patterned surface structures and we confirmed that our finite element computations of SAW dispersion in thin films and in one dimensional surface PnC structures agree with experimental results obtained by laser probe techniques. We analyzed the computations to guide device design in terms of sensitivity and joint spectral operating point. Next we conducted simulations and experiments to determine sensitivity and limit of detection for more conventional dispersive SAW devices and PnC sensors. Finally, we conducted extensive ozone detection trials on passive reflection mode SAW devices, using distinct components of the time dispersed response to compensate for the effect of temperature. The experimental work revealed that the devices may be used for dosimetry applications over periods of several days.

  15. Towards an Optimal Energy Consumption for Unattended Mobile Sensor Networks through Autonomous Sensor Redeployment

    PubMed Central

    Jia, Jie; Wen, Yingyou; Zhao, Dazhe

    2014-01-01

    Energy hole is an inherent problem caused by heavier traffic loads of sensor nodes nearer the sink because of more frequent data transmission, which is strongly dependent on the topology induced by the sensor deployment. In this paper, we propose an autonomous sensor redeployment algorithm to balance energy consumption and mitigate energy hole for unattended mobile sensor networks. First, with the target area divided into several equal width coronas, we present a mathematical problem modeling sensor node layout as well as transmission pattern to maximize network coverage and reduce communication cost. And then, by calculating the optimal node density for each corona to avoid energy hole, a fully distributed movement algorithm is proposed, which can achieve an optimal distribution quickly only by pushing or pulling its one-hop neighbors. The simulation results demonstrate that our algorithm achieves a much smaller average moving distance and a much longer network lifetime than existing algorithms and can eliminate the energy hole problem effectively. PMID:24949494

  16. Software structure for broadband wireless sensor network system

    NASA Astrophysics Data System (ADS)

    Kwon, Hyeokjun; Oh, Sechang; Yoon, Hargsoon; Varadan, Vijay K.

    2010-04-01

    Zigbee Sensor Network system has been investigating for monitoring and analyzing the data measured from a lot of sensors because the Zigbee Sensor Network has several advantages of low power consumption, compact size, and multi-node connection. However, it has a disadvantage not to be able to monitor the data measured from sensors at the remote area such as other room that is located at other city. This paper describes the software structure to compensate the defect with combining the Zigbee Sensor Network and wireless LAN technology for remote monitoring of measured sensor data. The software structure has both benefits of Zigbee Sensor Network and the advantage of wireless LAN. The software structure has three main software structures. The first software structure consists of the function in order to acquire the data from sensors and the second software structure is to gather the sensor data through wireless Zigbee and to send the data to Monitoring system by using wireless LAN. The second part consists of Linux packages software based on 2440 CPU (Samsung corp.), which has ARM9 core. The Linux packages include bootloader, device drivers, kernel, and applications, and the applications are TCP/IP server program, the program interfacing with Zigbee RF module, and wireless LAN program. The last part of software structure is to receive the sensor data through TCP/IP client program from Wireless Gate Unit and to display graphically measured data by using MATLAB program; the sensor data is measured on 100Hz sampling rate and the measured data has 10bit data resolution. The wireless data transmission rate per each channel is 1.6kbps.

  17. Developing a robust wireless sensor network structure for environmental sensing

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Oroza, C.; Glaser, S. D.; Bales, R. C.; Conklin, M. H.

    2013-12-01

    The American River Hydrologic Observatory is being strategically deployed as a real-time ground-based measurement network that delivers accurate and timely information on snow conditions and other hydrologic attributes with a previously unheard of granularity of time and space. The basin-scale network involves 18 sub-networks set out at physiographically representative locations spanning the seasonally snow-covered half of the 5000 km2 American river basin. Each sub-network, covering about a 1-km2 area, consists of 10 wirelessly networked sensing nodes that continuously measure and telemeter temperature, and snow depth; plus selected locations are equipped with sensors for relative humidity, solar radiation, and soil moisture at several depths. The sensor locations were chosen to maximize the variance sampled for snow depth within the basin. Network design and deployment involves an iterative but efficient process. After sensor-station locations are determined, a robust network of interlinking sensor stations and signal repeaters must be constructed to route sensor data to a central base station with a two-way communicable data uplink. Data can then be uploaded from site to remote servers in real time through satellite and cell modems. Signal repeaters are placed for robustness of a self-healing network with redundant signal paths to the base station. Manual, trial-and-error heuristic approaches for node placement are inefficient and labor intensive. In that approach field personnel must restructure the network in real time and wait for new network statistics to be calculated at the base station before finalizing a placement, acting without knowledge of the global topography or overall network structure. We show how digital elevation plus high-definition aerial photographs to give foliage coverage can optimize planning of signal repeater placements and guarantee a robust network structure prior to the physical deployment. We can also 'stress test' the final network

  18. Monitoring Induced Seismicity with Acoustic-Emission Sensors : The Calibration Problem

    NASA Astrophysics Data System (ADS)

    Plenkers, K.; Kwiatek, G.

    2012-12-01

    We study the effect that an uncalibrated acoustic-emission (AE) sensor has on source parameters using data of the JAGUARS project. The JAGUARS project recorded mining-induced seismicity in Mponeng Gold mine in Carletonville, South Africa in the frequency range 1 kHz < f < 180 kHz combining AE-sensors and accelerometers. Advanced monitoring of induced seismicity in underground structures sometimes includes today the use of high-frequency (f >> 1 kHz) AE monitoring systems. High-frequency monitoring allows the detection of seismic fractures on the centimeter scale and provides therefore important information about the migration of instabilities in the rock. Whereas the temporal-spatial analysis of seismic events recorded with AE sensors provides stable results, the analysis of source parameters including the estimation of magnitudes remains more challenging, because AE sensors are normally not well calibrated and exploit resonance frequencies to allow for high sensitivity. In our study the AE sensors are first calibrated in the frequency range 1kHz to 17 kHz relative to the well calibrated accelerometer. The calibration is possible due to the close employment of both sensor types, which allows to extract the sensor response (including the coupling effect) using signal deconvolution. We estimate three main resonance frequencies at about 2.5 kHz, 6 kHz and 10 kHz. Furthermore we calculate the directivity effect of the AE-sensor that influences the amplitude of the signal by up to - 15 dB. Second, we calculate the effect of the instrument response on the calculation of magnitude, magnitude-frequency distribution and static source parameters. We study magnitudes, magitude-frequency distributions and static source parameters using both the calibrated sensors, as well as the uncalibrated AE sensors. We show the significant uncertainty that is indroduced owing to the AE sensor response and conclude that source parameters often have high uncertainties and are not reliable

  19. Mobile Sensor Networks for Inspection Tasks in Harsh Industrial Environments

    PubMed Central

    Mulder, Jacob; Wang, Xinyu; Ferwerda, Franke; Cao, Ming

    2010-01-01

    Recent advances in sensor technology have enabled the fast development of mobile sensor networks operating in various unknown and sometimes hazardous environments. In this paper, we introduce one integrative approach to design, analyze and test distributed control algorithms to coordinate a network of autonomous mobile sensors by utilizing both simulation tools and a robotic testbed. The research has been carried out in the context of the mobile sensing project, PicoSmart, in the northern provinces of the Netherlands for the inspection of natural gas pipelines. PMID:22294889

  20. Mobile sensor networks for inspection tasks in harsh industrial environments.

    PubMed

    Mulder, Jacob; Wang, Xinyu; Ferwerda, Franke; Cao, Ming

    2010-01-01

    Recent advances in sensor technology have enabled the fast development of mobile sensor networks operating in various unknown and sometimes hazardous environments. In this paper, we introduce one integrative approach to design, analyze and test distributed control algorithms to coordinate a network of autonomous mobile sensors by utilizing both simulation tools and a robotic testbed. The research has been carried out in the context of the mobile sensing project, PicoSmart, in the northern provinces of the Netherlands for the inspection of natural gas pipelines.

  1. Dynamic Load Balancing Data Centric Storage for Wireless Sensor Networks

    PubMed Central

    Song, Seokil; Bok, Kyoungsoo; Kwak, Yun Sik; Goo, Bongeun; Kwak, Youngsik; Ko, Daesik

    2010-01-01

    In this paper, a new data centric storage that is dynamically adapted to the work load changes is proposed. The proposed data centric storage distributes the load of hot spot areas to neighboring sensor nodes by using a multilevel grid technique. The proposed method is also able to use existing routing protocols such as GPSR (Greedy Perimeter Stateless Routing) with small changes. Through simulation, the proposed method enhances the lifetime of sensor networks over one of the state-of-the-art data centric storages. We implement the proposed method based on an operating system for sensor networks, and evaluate the performance through running based on a simulation tool. PMID:22163472

  2. Comparison of Event Detection Methods for Centralized Sensor Networks

    NASA Technical Reports Server (NTRS)

    Sauvageon, Julien; Agogiono, Alice M.; Farhang, Ali; Tumer, Irem Y.

    2006-01-01

    The development of an Integrated Vehicle Health Management (IVHM) for space vehicles has become a great concern. Smart Sensor Networks is one of the promising technologies that are catching a lot of attention. In this paper, we propose to a qualitative comparison of several local event (hot spot) detection algorithms in centralized redundant sensor networks. The algorithms are compared regarding their ability to locate and evaluate the event under noise and sensor failures. The purpose of this study is to check if the ratio performance/computational power of the Mote Fuzzy Validation and Fusion algorithm is relevant compare to simpler methods.

  3. A distributed general multi-sensor cardinalized probability hypothesis density (CPHD) filter for sensor networks

    NASA Astrophysics Data System (ADS)

    Datta Gupta, S.; Nannuru, S.; Coates, M.; Rabbat, M.

    2015-05-01

    We develop a distributed cardinalized probability hypothesis density (CPHD) filter that can be deployed in a sensor network to process the measurements of multiple sensors that make conditionally independent measurements. In contrast to the majority of the related work, which involves performing local filter updates and then exchanging data to fuse the local intensity functions and cardinality distributions, we strive to approximate the update step that a centralized multi-sensor CPHD filter would perform.

  4. Enhanced Sensitive Love Wave Surface Acoustic Wave Sensor Designed for Immunoassay Formats

    PubMed Central

    Puiu, Mihaela; Gurban, Ana-Maria; Rotariu, Lucian; Brajnicov, Simona; Viespe, Cristian; Bala, Camelia

    2015-01-01

    We report a Love wave surface acoustic wave (LW-SAW) immunosensor designed for the detection of high molecular weight targets in liquid samples, amenable also for low molecular targets in surface competition assays. We implemented a label-free interaction protocol similar to other surface plasmon resonance bioassays having the advantage of requiring reduced time analysis. The fabricated LW-SAW sensor supports the detection of the target in the nanomolar range, and can be ultimately incorporated in portable devices, suitable for point-of-care testing (POCT) applications. PMID:25951337

  5. Enhanced sensitive love wave surface acoustic wave sensor designed for immunoassay formats.

    PubMed

    Puiu, Mihaela; Gurban, Ana-Maria; Rotariu, Lucian; Brajnicov, Simona; Viespe, Cristian; Bala, Camelia

    2015-05-05

    We report a Love wave surface acoustic wave (LW-SAW) immunosensor designed for the detection of high molecular weight targets in liquid samples, amenable also for low molecular targets in surface competition assays. We implemented a label-free interaction protocol similar to other surface plasmon resonance bioassays having the advantage of requiring reduced time analysis. The fabricated LW-SAW sensor supports the detection of the target in the nanomolar range, and can be ultimately incorporated in portable devices, suitable for point-of-care testing (POCT) applications.

  6. Integrated acoustic emission/vibration sensor for detecting damage in aircraft drive train components

    NASA Astrophysics Data System (ADS)

    Godínez-Azcuaga, Valery F.; Ozevin, Didem; Finlayson, Richard D.; Anastasopoulos, Athanasios; Tsimogiannis, Apostolos

    2007-04-01

    Diaphragm-type couplings are high misalignment torque and speed transfer components used in aircrafts. Crack development in such couplings, or in the drive train in general, can lead to component failure that can bring down an aircraft. Real time detection of crack formation and growth is important to prevent such catastrophic failures. However, there is no single Nondestructive Monitoring method available that is capable of assessing the early stages of crack growth in such components. While vibration based damage identification techniques are used, they cannot detect cracks until they reach a considerable size, which makes detection of the onset of cracking extremely difficult. Acoustic Emission (AE) can detect and monitor early stage crack growth, however excessive background noise can mask acoustic emissions produced by crack initiation. Fusion of the two mentioned techniques can increase the accuracy of measurement and minimize false alarms. However, a monitoring system combining both techniques could prove too large and heavy for the already restricted space available in aircrafts. In the present work, we will present a newly developed integrated Acoustic Emission/Vibration (AE/VIB) combined sensor which can operate in the temperature range of -55°F to 257°F and in high EMI environment. This robust AE/VIB sensor has a frequency range of 5 Hz-2 kHz for the vibration component and a range of 200-400 kHz for the acoustic emission component. The sensor weight is comparable to accelerometers currently used in flying aircraft. Traditional signal processing approaches are not effective due to high signal attenuation and strong background noise conditions, commonly found in aircraft drive train systems. As an alternative, we will introduce a new Supervised Pattern Recognition (SPR) methodology that allows for simultaneous processing of the signals detected by the AE/VIB sensor and their classification in near-real time, even in these adverse conditions. Finally, we

  7. Optical Fiber Networks for Remote Fiber Optic Sensors

    PubMed Central

    Fernandez-Vallejo, Montserrat; Lopez-Amo, Manuel

    2012-01-01

    This paper presents an overview of optical fiber sensor networks for remote sensing. Firstly, the state of the art of remote fiber sensor systems has been considered. We have summarized the great evolution of these systems in recent years; this progress confirms that fiber-optic remote sensing is a promising technology with a wide field of practical applications. Afterwards, the most representative remote fiber-optic sensor systems are briefly explained, discussing their schemes, challenges, pros and cons. Finally, a synopsis of the main factors to take into consideration in the design of a remote sensor system is gathered. PMID:22666011

  8. Optical fiber networks for remote fiber optic sensors.

    PubMed

    Fernandez-Vallejo, Montserrat; Lopez-Amo, Manuel

    2012-01-01

    This paper presents an overview of optical fiber sensor networks for remote sensing. Firstly, the state of the art of remote fiber sensor systems has been considered. We have summarized the great evolution of these systems in recent years; this progress confirms that fiber-optic remote sensing is a promising technology with a wide field of practical applications. Afterwards, the most representative remote fiber-optic sensor systems are briefly explained, discussing their schemes, challenges, pros and cons. Finally, a synopsis of the main factors to take into consideration in the design of a remote sensor system is gathered. PMID:22666011

  9. Application of a novel optical fiber sensor to detection of acoustic emissions by various damages in CFRP laminates

    NASA Astrophysics Data System (ADS)

    Wu, Qi; Yu, Fengming; Okabe, Yoji; Kobayashi, Satoshi

    2015-01-01

    In this research, we applied a novel optical fiber sensor, phase-shifted fiber Bragg grating balanced sensor with high sensitivity and broad bandwidth, to acoustic emission (AE) detection in carbon fiber reinforced plastics (CFRPs). AE signals generated in the tensile testing of angle-ply and cross-ply CFRP laminates were both detected by the novel optical fiber sensor and traditional PZT sensors. The cumulative hits detected by both sensors coincided after applying simple data processing to eliminate the noise, and clearly exhibited Kaiser effect and Felicity effect. Typical AE signals detected by both sensors were discussed and were tried to relate to micro CFRP damages observed via microscope. These results demonstrate that this novel optical fiber sensor can reliably detect AE signals from various damages. It has the potential to be used in practical AE detection, as an alternative to the piezoelectric PZT sensor.

  10. Networking of optical fiber sensors for extreme environments

    NASA Astrophysics Data System (ADS)

    Peters, Kara

    2016-04-01

    One of the major benefits of optical fiber sensors for applications to structural health monitoring and other structural measurements is their inherent multiplexing capabilities, meaning that a large number of sensing locations can be achieved with a single optical fiber. It has been well demonstrated that point wise sensors can be multiplexed to form sensor networks or optical fibers integrated with distributed sensing techniques. The spacing between sensing locations can also be tuned to match different length scales of interest. This article presents an overview of directions to adapt optical fiber sensor networking techniques into new applications where limitations such as available power or requirements for high data acquisition speeds are a driving factor. In particular, the trade-off between high fidelity sensor information vs. rapid signal processing or data acquisition is discussed.

  11. Wireless thermal sensor network with adaptive low power design.

    PubMed

    Lee, Ho-Yin; Chen, Shih-Lun; Chen, Chiung-An; Huang, Hong-Yi; Luo, Ching-Hsing

    2007-01-01

    There is an increasing need to develop flexible, reconfigurable, and intelligent low power wireless sensor network (WSN) system for healthcare applications. Technical advancements in micro-sensors, MEMS devices, low power electronics, and radio frequency circuits have enabled the design and development of such highly integrated system. In this paper, we present our proposed wireless thermal sensor network system, which is separated into control and data paths. Both of these paths have their own transmission frequencies. The control path sends the power and function commands from computer to each sensor elements by 2.4GHz RF circuits and the data path transmits measured data by 2.4GHz in sensor layer and 60GHz in higher layers. This hierarchy architecture would make reconfigurable mapping and pipeline applications on WSN possibly, and the average power consumption can be efficiently reduced about 60% by using the adaptive technique. PMID:18003354

  12. Standards-Based Wireless Sensor Networking Protocols for Spaceflight Applications

    NASA Technical Reports Server (NTRS)

    Wagner, Raymond S.

    2010-01-01

    Wireless sensor networks (WSNs) have the capacity to revolutionize data gathering in both spaceflight and terrestrial applications. WSNs provide a huge advantage over traditional, wired instrumentation since they do not require wiring trunks to connect sensors to a central hub. This allows for easy sensor installation in hard to reach locations, easy expansion of the number of sensors or sensing modalities, and reduction in both system cost and weight. While this technology offers unprecedented flexibility and adaptability, implementing it in practice is not without its difficulties. Recent advances in standards-based WSN protocols for industrial control applications have come a long way to solving many of the challenges facing practical WSN deployments. In this paper, we will overview two of the more promising candidates - WirelessHART from the HART Communication Foundation and ISA100.11a from the International Society of Automation - and present the architecture for a new standards-based sensor node for networking and applications research.

  13. Debonding detection using a self-calibration sensor network

    NASA Astrophysics Data System (ADS)

    Li, Fucai; Murayama, Hideaki; Kageyama, Kazuro; Meng, Guang; Ohsawa, Isamu; Shirai, Takehiro

    2010-06-01

    Adhesively bonded joints between two plates are gradually receiving increasing acceptance in safety-critical structures, and therefore methods for nondestructive evaluation (NDE) of adhesive joints have drawn much attention. In this paper, specimens with lap splice joints are prepared for the purpose of guided-wave-based debonding damage detection. Fibre optic Doppler (FOD) sensors are used to acquire guided ultrasonic waves propagating in two kinds of bonded specimens, namely aluminium and carbon fibre reinforced plastic (CFRP) assemblies. To overcome the drawbacks of sensor networks in conventional structural health monitoring systems, a self-calibration sensor network is constructed based on elastic analyses of the bonded structures. By using the proposed sensor network, both the baseline measurement and the defect-related guided wave signals can be acquired in one excitation experiment. Moreover, complicated signal interpretation is also avoided by using the simplest feature, arrival time, of the ultrasonic wave signals.

  14. A small low-power networked and versatile sensor interface

    NASA Astrophysics Data System (ADS)

    Vincent, Peter S.; McMahon, Phillip J.; Muscat, Richard F.; Zeve, Ladislav; Wilson, Alan R.

    2007-01-01

    Defence Science and Technology Organisation (DSTO) has developed a low power RS485 sensor network that can be hardware configured at design time from a number of modules, depending on its final application. The core predesigned module includes network communications, microprocessor control and digital input/output. A number of analogue sensor interface modules can easily be added to this core. In addition, the software is also of modular design consisting of a set of core operating routines and a set of routines for controlling sensor operations that can be downloaded or upgraded in the field. Prime consideration in this development has been given to the need for small size, low weight, low power and versatility of operation. The hardware is based around the Texas Instruments MSP430® micro-controller. This paper will present some of the considerations leading to the design and examples of applications of the sensor network.

  15. Voronoi-based localisation algorithm for mobile sensor networks

    NASA Astrophysics Data System (ADS)

    Guan, Zixiao; Zhang, Yongtao; Zhang, Baihai; Dong, Lijing

    2016-11-01

    Localisation is an essential and important part in wireless sensor networks (WSNs). Many applications require location information. So far, there are less researchers studying on mobile sensor networks (MSNs) than static sensor networks (SSNs). However, MSNs are required in more and more areas such that the number of anchor nodes can be reduced and the location accuracy can be improved. In this paper, we firstly propose a range-free Voronoi-based Monte Carlo localisation algorithm (VMCL) for MSNs. We improve the localisation accuracy by making better use of the information that a sensor node gathers. Then, we propose an optimal region selection strategy of Voronoi diagram based on VMCL, called ORSS-VMCL, to increase the efficiency and accuracy for VMCL by adapting the size of Voronoi area during the filtering process. Simulation results show that the accuracy of these two algorithms, especially ORSS-VMCL, outperforms traditional MCL.

  16. Multiple image sensor data fusion through artificial neural networks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With multisensor data fusion technology, the data from multiple sensors are fused in order to make a more accurate estimation of the environment through measurement, processing and analysis. Artificial neural networks are the computational models that mimic biological neural networks. With high per...

  17. 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.…

  18. A new sparse design method on phased array-based acoustic emission sensor for partial discharge detection

    NASA Astrophysics Data System (ADS)

    Xie, Qing; Cheng, Shuyi; Lü, Fangcheng; Li, Yanqing

    2014-03-01

    The acoustic detecting performance of a partial discharge (PD) ultrasonic sensor array can be improved by increasing the number of array elements. However, it will increase the complexity and cost of the PD detection system. Therefore, a sparse sensor with an optimization design can be chosen to ensure good acoustic performance. In this paper, first, a quantitative method is proposed for evaluating the acoustic performance of a square PD ultrasonic array sensor. Second, a method of sparse design is presented to combine the evaluation method with the chaotic monkey algorithm. Third, an optimal sparse structure of a 3 × 3 square PD ultrasonic array sensor is deduced. It is found that, under different sparseness and sparse structure, the main beam width of the directivity function shows a small variation, while the sidelobe amplitude shows a bigger variation. For a specific sparseness, the acoustic performance under the optimal sparse structure is close to that using a full array. Finally, some simulations based on the above method show that, for certain sparseness, the sensor with the optimal sparse structure exhibits superior positioning accuracy compared to that with a stochastic one. The sensor array structure may be chosen according to the actual requirements for an actual engineering application.

  19. Mobile sensor network noise reduction and recalibration using a Bayesian network

    NASA Astrophysics Data System (ADS)

    Xiang, Y.; Tang, Y.; Zhu, W.

    2016-02-01

    People are becoming increasingly interested in mobile air quality sensor network applications. By eliminating the inaccuracies caused by spatial and temporal heterogeneity of pollutant distributions, this method shows great potential for atmospheric research. However, systems based on low-cost air quality sensors often suffer from sensor noise and drift. For the sensing systems to operate stably and reliably in real-world applications, those problems must be addressed. In this work, we exploit the correlation of different types of sensors caused by cross sensitivity to help identify and correct the outlier readings. By employing a Bayesian network based system, we are able to recover the erroneous readings and recalibrate the drifted sensors simultaneously. Our method improves upon the state-of-art Bayesian belief network techniques by incorporating the virtual evidence and adjusting the sensor calibration functions recursively.Specifically, we have (1) designed a system based on the Bayesian belief network to detect and recover the abnormal readings, (2) developed methods to update the sensor calibration functions infield without requirement of ground truth, and (3) extended the Bayesian network with virtual evidence for infield sensor recalibration. To validate our technique, we have tested our technique with metal oxide sensors measuring NO2, CO, and O3 in a real-world deployment. Compared with the existing Bayesian belief network techniques, results based on our experiment setup demonstrate that our system can reduce error by 34.1 % and recover 4 times more data on average.

  20. A wireless demodulation system for passive surface acoustic wave torque sensor.

    PubMed

    Ji, Xiaojun; Fan, Yanping; Qi, Hongli; Chen, Jing; Han, Tao; Cai, Ping

    2014-12-01

    Surface acoustic wave (SAW) resonators are utilized as torque sensors for their passive and wireless features. However, the response of a SAW torque sensor is difficult to detect because of the transient response duration and interruption of channel noise, which limit the application of SAW torque sensors. The sensitive mechanism and response function of a passive wireless SAW torque sensor are analyzed in this study. A novel demodulation system involving both hardware and software is developed for the SAW torque sensor. A clipping amplifier is utilized in the hardware to widen the dynamic response range and increase the length of the valid signal. Correlation extension and centroid algorithms are designed to lengthen the received signal and improve the estimation accuracy of the center frequency of the response signal, respectively. Meanwhile, a fast binary search algorithm is proposed to accelerate the scanning cycle according to the developed response function. Finally, the SAW torque sensor demodulation system is set up and SAW resonators with high sensitivity are fabricated on a quartz substrate. The presented demodulation system is tested, and a standard deviation of 0.28 kHz is achieved. This value is much smaller than that of classic and modern spectrum estimation methods. The sensitivity of resonance frequency shift versus torque on the shaft of the assembled senor is 2.03 kHz/Nm; the coefficient of determination is 0.999, and the linearity is 0.87%. Experimental results verify the validity and feasibility of the proposed SAW torque sensor demodulation system. PMID:25554317

  1. Dynamic high throughput screening of chemical libraries using acoustic-wave sensor system

    NASA Astrophysics Data System (ADS)

    Potyrailo, Radislav A.; May, Ralph J.

    2002-03-01

    We report a novel sensor-based high throughput screening (HTS) system for identification and quantitation of volatile substances in combinatorial chemical libraries. The measurement method employs a combination of a periodic introduction of a minute amount of a liquid sample into the HTS system, rapid evaporation of volatile components in the sample at room temperature, and dynamic measurement of a generated vapor pulse. These measurements are performed using an array of four 10 MHz acoustic-wave thickness-shear mode sensors coated with different chemically sensitive films. Developed HTS system is applied for screening of multiple samples such as those created in combinatorial chemical libraries of catalyst candidates in an industrially important arene oxidation process. The temporal modulation of the concentration of analyte vapors and measurement of both the temporal profile and the magnitude of the response improves sensor selectivity and makes possible robust identification and quantitation of arene oxidation components such as cresol and benzoquinone in multicomponent combinatorial mixtures with reduced number of sensors in the array. Different solvents such as water, acetonitrile, benzene, and toluene do not alter the response of sensors to analytes. Depending on the gas flow rate, quantitative measurements are performed 10-150 s after the sample introduction and provide significant throughput advantage over gas-chromatographic instruments. Determinations of mixtures of analytes in a variety of solvents are performed using multivariate locally weighted regression. This data analysis method provides the root mean squared error of prediction of less than 2 μg when measurements of cresol and benzoquinone amounts ranging from 0 to 50 μg are performed in 2 μL samples. This method of dynamic sensor-based measurements allows for instrument miniaturization and increases the usefulness of the instrument in space-limited applications. Upon operation of multiple

  2. Probabilistic Assessment of High-Throughput Wireless Sensor Networks.

    PubMed

    Kim, Robin E; Mechitov, Kirill; Sim, Sung-Han; Spencer, Billie F; Song, Junho

    2016-01-01

    Structural health monitoring (SHM) using wireless smart sensors (WSS) has the potential to provide rich information on the state of a structure. However, because of their distributed nature, maintaining highly robust and reliable networks can be challenging. Assessing WSS network communication quality before and after finalizing a deployment is critical to achieve a successful WSS network for SHM purposes. Early studies on WSS network reliability mostly used temporal signal indicators, composed of a smaller number of packets, to assess the network reliability. However, because the WSS networks for SHM purpose often require high data throughput, i.e., a larger number of packets are delivered within the communication, such an approach is not sufficient. Instead, in this study, a model that can assess, probabilistically, the long-term performance of the network is proposed. The proposed model is based on readily-available measured data sets that represent communication quality during high-throughput data transfer. Then, an empirical limit-state function is determined, which is further used to estimate the probability of network communication failure. Monte Carlo simulation is adopted in this paper and applied to a small and a full-bridge wireless networks. By performing the proposed analysis in complex sensor networks, an optimized sensor topology can be achieved. PMID:27258270

  3. Probabilistic Assessment of High-Throughput Wireless Sensor Networks

    PubMed Central

    Kim, Robin E.; Mechitov, Kirill; Sim, Sung-Han; Spencer, Billie F.; Song, Junho

    2016-01-01

    Structural health monitoring (SHM) using wireless smart sensors (WSS) has the potential to provide rich information on the state of a structure. However, because of their distributed nature, maintaining highly robust and reliable networks can be challenging. Assessing WSS network communication quality before and after finalizing a deployment is critical to achieve a successful WSS network for SHM purposes. Early studies on WSS network reliability mostly used temporal signal indicators, composed of a smaller number of packets, to assess the network reliability. However, because the WSS networks for SHM purpose often require high data throughput, i.e., a larger number of packets are delivered within the communication, such an approach is not sufficient. Instead, in this study, a model that can assess, probabilistically, the long-term performance of the network is proposed. The proposed model is based on readily-available measured data sets that represent communication quality during high-throughput data transfer. Then, an empirical limit-state function is determined, which is further used to estimate the probability of network communication failure. Monte Carlo simulation is adopted in this paper and applied to a small and a full-bridge wireless networks. By performing the proposed analysis in complex sensor networks, an optimized sensor topology can be achieved. PMID:27258270

  4. Probabilistic Assessment of High-Throughput Wireless Sensor Networks.

    PubMed

    Kim, Robin E; Mechitov, Kirill; Sim, Sung-Han; Spencer, Billie F; Song, Junho

    2016-01-01

    Structural health monitoring (SHM) using wireless smart sensors (WSS) has the potential to provide rich information on the state of a structure. However, because of their distributed nature, maintaining highly robust and reliable networks can be challenging. Assessing WSS network communication quality before and after finalizing a deployment is critical to achieve a successful WSS network for SHM purposes. Early studies on WSS network reliability mostly used temporal signal indicators, composed of a smaller number of packets, to assess the network reliability. However, because the WSS networks for SHM purpose often require high data throughput, i.e., a larger number of packets are delivered within the communication, such an approach is not sufficient. Instead, in this study, a model that can assess, probabilistically, the long-term performance of the network is proposed. The proposed model is based on readily-available measured data sets that represent communication quality during high-throughput data transfer. Then, an empirical limit-state function is determined, which is further used to estimate the probability of network communication failure. Monte Carlo simulation is adopted in this paper and applied to a small and a full-bridge wireless networks. By performing the proposed analysis in complex sensor networks, an optimized sensor topology can be achieved.

  5. Converging Redundant Sensor Network Information for Improved Building Control

    SciTech Connect

    Dale Tiller; D. Phil; Gregor Henze; Xin Guo

    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-plan 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.

  6. Detection of cells captured with antigens on shear horizontal surface-acoustic-wave sensors.

    PubMed

    Hao, Hsu-Chao; Chang, Hwan-You; Wang, Tsung-Pao; Yao, Da-Jeng

    2013-02-01

    Techniques to separate cells are widely applied in immunology. The technique to separate a specific antigen on a microfluidic platform involves the use of a shear horizontal surface-acoustic-wave (SH-SAW) sensor. With specific antibodies conjugated onto the surface of the SH-SAW sensors, this technique can serve to identify specific cells in bodily fluids. Jurkat cells, used as a target in this work, provide a model of cells in small abundance (1:1000) for isolation and purification with the ultimate goal of targeting even more dilute cells. T cells were separated from a mixed-cell medium on a chip (Jurkat cells/K562 cells, 1/1000). A novel microchamber was developed to capture cells during the purification, which required a large biosample. Cell detection was demonstrated through the performance of genetic identification on the chip.

  7. Open Hardware: A Role to Play in Wireless Sensor Networks?

    PubMed Central

    Fisher, Roy; Ledwaba, Lehlogonolo; Hancke, Gerhard; Kruger, Carel

    2015-01-01

    The concept of the Internet of Things is rapidly becoming a reality, with many applications being deployed within industrial and consumer sectors. At the ‘thing’ level—devices and inter-device network communication—the core technical building blocks are generally the same as those found in wireless sensor network implementations. For the Internet of Things to continue growing, we need more plentiful resources for building intelligent devices and sensor networks. Unfortunately, current commercial devices, e.g., sensor nodes and network gateways, tend to be expensive and proprietary, which presents a barrier to entry and arguably slows down further development. There are, however, an increasing number of open embedded platforms available and also a wide selection of off-the-shelf components that can quickly and easily be built into device and network gateway solutions. The question is whether these solutions measure up to built-for-purpose devices. In the paper, we provide a comparison of existing built-for-purpose devices against open source devices. For comparison, we have also designed and rapidly prototyped a sensor node based on off-the-shelf components. We show that these devices compare favorably to built-for-purpose devices in terms of performance, power and cost. Using open platforms and off-the-shelf components would allow more developers to build intelligent devices and sensor networks, which could result in a better overall development ecosystem, lower barriers to entry and rapid growth in the number of IoT applications. PMID:25803706

  8. Open hardware: a role to play in wireless sensor networks?

    PubMed

    Fisher, Roy; Ledwaba, Lehlogonolo; Hancke, Gerhard; Kruger, Carel

    2015-03-20

    The concept of the Internet of Things is rapidly becoming a reality, with many applications being deployed within industrial and consumer sectors. At the 'thing' level-devices and inter-device network communication-the core technical building blocks are generally the same as those found in wireless sensor network implementations. For the Internet of Things to continue growing, we need more plentiful resources for building intelligent devices and sensor networks. Unfortunately, current commercial devices, e.g., sensor nodes and network gateways, tend to be expensive and proprietary, which presents a barrier to entry and arguably slows down further development. There are, however, an increasing number of open embedded platforms available and also a wide selection of off-the-shelf components that can quickly and easily be built into device and network gateway solutions. The question is whether these solutions measure up to built-for-purpose devices. In the paper, we provide a comparison of existing built-for-purpose devices against open source devices. For comparison, we have also designed and rapidly prototyped a sensor node based on off-the-shelf components. We show that these devices compare favorably to built-for-purpose devices in terms of performance, power and cost. Using open platforms and off-the-shelf components would allow more developers to build intelligent devices and sensor networks, which could result in a better overall development ecosystem, lower barriers to entry and rapid growth in the number of IoT applications.

  9. Consistent Steering System using SCTP for Bluetooth Scatternet Sensor Network

    NASA Astrophysics Data System (ADS)

    Dhaya, R.; Sadasivam, V.; Kanthavel, R.

    2012-12-01

    Wireless communication is the best way to convey information from source to destination with flexibility and mobility and Bluetooth is the wireless technology suitable for short distance. On the other hand a wireless sensor network (WSN) consists of spatially distributed autonomous sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants. Using Bluetooth piconet wireless technique in sensor nodes creates limitation in network depth and placement. The introduction of Scatternet solves the network restrictions with lack of reliability in data transmission. When the depth of the network increases, it results in more difficulties in routing. No authors so far focused on the reliability factors of Scatternet sensor network's routing. This paper illustrates the proposed system architecture and routing mechanism to increase the reliability. The another objective is to use reliable transport protocol that uses the multi-homing concept and supports multiple streams to prevent head-of-line blocking. The results show that the Scatternet sensor network has lower packet loss even in the congestive environment than the existing system suitable for all surveillance applications.

  10. Open hardware: a role to play in wireless sensor networks?

    PubMed

    Fisher, Roy; Ledwaba, Lehlogonolo; Hancke, Gerhard; Kruger, Carel

    2015-01-01

    The concept of the Internet of Things is rapidly becoming a reality, with many applications being deployed within industrial and consumer sectors. At the 'thing' level-devices and inter-device network communication-the core technical building blocks are generally the same as those found in wireless sensor network implementations. For the Internet of Things to continue growing, we need more plentiful resources for building intelligent devices and sensor networks. Unfortunately, current commercial devices, e.g., sensor nodes and network gateways, tend to be expensive and proprietary, which presents a barrier to entry and arguably slows down further development. There are, however, an increasing number of open embedded platforms available and also a wide selection of off-the-shelf components that can quickly and easily be built into device and network gateway solutions. The question is whether these solutions measure up to built-for-purpose devices. In the paper, we provide a comparison of existing built-for-purpose devices against open source devices. For comparison, we have also designed and rapidly prototyped a sensor node based on off-the-shelf components. We show that these devices compare favorably to built-for-purpose devices in terms of performance, power and cost. Using open platforms and off-the-shelf components would allow more developers to build intelligent devices and sensor networks, which could result in a better overall development ecosystem, lower barriers to entry and rapid growth in the number of IoT applications. PMID:25803706

  11. Distributed Sensor Fusion for Scalar Field Mapping Using Mobile Sensor Networks.

    PubMed

    La, Hung Manh; Sheng, Weihua

    2013-04-01

    In this paper, autonomous mobile sensor networks are deployed to measure a scalar field and build its map. We develop a novel method for multiple mobile sensor nodes to build this map using noisy sensor measurements. Our method consists of two parts. First, we develop a distributed sensor fusion algorithm by integrating two different distributed consensus filters to achieve cooperative sensing among sensor nodes. This fusion algorithm has two phases. In the first phase, the weighted average consensus filter is developed, which allows each sensor node to find an estimate of the value of the scalar field at each time step. In the second phase, the average consensus filter is used to allow each sensor node to find a confidence of the estimate at each time step. The final estimate of the value of the scalar field is iteratively updated during the movement of the mobile sensors via weighted average. Second, we develop the distributed flocking-control algorithm to drive the mobile sensors to form a network and track the virtual leader moving along the field when only a small subset of the mobile sensors know the information of the leader. Experimental results are provided to demonstrate our proposed algorithms.

  12. Automated Negotiation for Resource Assignment in Wireless Surveillance Sensor Networks

    PubMed Central

    de la Hoz, Enrique; Gimenez-Guzman, Jose Manuel; Marsa-Maestre, Ivan; Orden, David

    2015-01-01

    Due to the low cost of CMOS IP-based cameras, wireless surveillance sensor networks have emerged as a new application of sensor networks able to monitor public or private areas or even country borders. Since these networks are bandwidth intensive and the radioelectric spectrum is limited, especially in unlicensed bands, it is mandatory to assign frequency channels in a smart manner. In this work, we propose the application of automated negotiation techniques for frequency assignment. Results show that these techniques are very suitable for the problem, being able to obtain the best solutions among the techniques with which we have compared them. PMID:26610512

  13. Automated Negotiation for Resource Assignment in Wireless Surveillance Sensor Networks.

    PubMed

    de la Hoz, Enrique; Gimenez-Guzman, Jose Manuel; Marsa-Maestre, Ivan; Orden, David

    2015-01-01

    Due to the low cost of CMOS IP-based cameras, wireless surveillance sensor networks have emerged as a new application of sensor networks able to monitor public or private areas or even country borders. Since these networks are bandwidth intensive and the radioelectric spectrum is limited, especially in unlicensed bands, it is mandatory to assign frequency channels in a smart manner. In this work, we propose the application of automated negotiation techniques for frequency assignment. Results show that these techniques are very suitable for the problem, being able to obtain the best solutions among the techniques with which we have compared them.

  14. Time Synchronization in Hierarchical TESLA Wireless Sensor Networks

    SciTech Connect

    Jason L. Wright; Milos Manic

    2009-08-01

    Time synchronization and event time correlation are important in wireless sensor networks. In particular, time is used to create a sequence events or time line to answer questions of cause and effect. Time is also used as a basis for determining the freshness of received packets and the validity of cryptographic certificates. This paper presents secure method of time synchronization and event time correlation for TESLA-based hierarchical wireless sensor networks. The method demonstrates that events in a TESLA network can be accurately timestamped by adding only a few pieces of data to the existing protocol.

  15. Impedance analysis of nano thickness layered AlGaN acoustic sensor deposited by thermionic vacuum arc

    NASA Astrophysics Data System (ADS)

    Özen, Soner; Bilgiç, Eyüp; Gülmez, Gülay; Şenay, Volkan; Pat, Suat; Korkmaz, Şadan; Mohammadigharehbagh, Reza

    2016-03-01

    In this study, AlGaN acoustic sensor was deposited on aluminum metal substrate by thermionic vacuum arc (TVA) method for the first time. Gallium materials are used in many applications for optoelectronic device and semiconductor technology. Thermionic vacuum arc is the deposition technology for the variously materials and applications field. The thickness of the acoustic sensor is in deposited as nano layer. Impedance analyses were realized. Also, TVA production parameters and some properties of the deposited layers were investigated. TVA is a fast deposition technology for the gallium compounds and doped gallium compounds. Obtained results show that AlGaN materials are very promising materials. Moreover, these acoustic sensors have been produced by TVA technology.

  16. Distributed Detection of Wormhole Attacks in Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    de Graaf, Rennie; Hegazy, Islam; Horton, Jeffrey; Safavi-Naini, Reihaneh

    Sensors in a wireless sensor network depend on their neighbours to route their messages. Yet, routing protocols in wireless sensor network are vulnerable to different types of attacks. In this paper, we consider the wormhole attack in which the adversary diverts traffic from one part of the network to another part by introducing a low cost tunnel between the two parts. We introduce a distributed intrusion detection system that monitors the communication in the network and propose a criterion for the placement of intrusion detection nodes. The intrusion detection system searches for violations of that criterion to detect wormholes of length above a certain minimum value. We evaluate the effectiveness of our system in a simulated environment. The experiments show that our system can detect 100% of the wormholes that are beyond the communication range of the intrusion detection nodes. Finally, we discuss our results and show directions for future work.

  17. Semantic Visualization of Wireless Sensor Networks for Elderly Monitoring

    NASA Astrophysics Data System (ADS)

    Stocklöw, Carsten; Kamieth, Felix

    In the area of Ambient Intelligence, Wireless Sensor Networks are commonly used for user monitoring purposes like health monitoring and user localization. Existing work on visualization of wireless sensor networks focuses mainly on displaying individual nodes and logical, graph-based topologies. This way, the relation to the real-world deployment is lost. This paper presents a novel approach for visualization of wireless sensor networks and interaction with complex services on the nodes. The environment is realized as a 3D model, and multiple nodes, that are worn by a single individual, are grouped together to allow an intuitive interface for end users. We describe application examples and show that our approach allows easier access to network information and functionality by comparing it with existing solutions.

  18. Aircraft IR/acoustic detection evaluation. Volume 2: Development of a ground-based acoustic sensor system for the detection of subsonic jet-powered aircraft

    NASA Technical Reports Server (NTRS)

    Kraft, Robert E.

    1992-01-01

    The design and performance of a ground-based acoustic sensor system for the detection of subsonic jet-powered aircraft is described and specified. The acoustic detection system performance criteria will subsequently be used to determine target detection ranges for the subject contract. Although the defined system has never been built and demonstrated in the field, the design parameters were chosen on the basis of achievable technology and overall system practicality. Areas where additional information is needed to substantiate the design are identified.

  19. [Advances in sensor node and wireless communication technology of body sensor network].

    PubMed

    Lin, Weibing; Lei, Sheng; Wei, Caihong; Li, Chunxiang; Wang, Cang

    2012-06-01

    With the development of the wireless communication technology, implantable biosensor technology, and embedded system technology, Body Sensor Network (BSN) as one branch of wireless sensor networks and important part of the Internet of things has caught more attention of researchers and enterprises. This paper offers the basic concept of the BSN and analyses the related research. We focus on sensor node and wireless communication technology from perspectives of technology challenges, research advance and development trend in the paper. Besides, we also present a relative overview of domestic and overseas projects for the BSN. PMID:22826960

  20. Wireless Sensor Networks Energy-Efficient MAC Protocol

    NASA Astrophysics Data System (ADS)

    Lijuan, Du; Yuanpeng, Wang; WeiPeng, Jing

    This paper presents a new wireless sensor network energy-efficient MAC protocol, ES-MAC protocol, and shows the results of simulation experiments. During the transmission the nodes do not send ACK packages while use a small amount of new information packets, so they can reduce unnecessary energy loss and wasted time. The theoretical analysis and simulation results show that ES-MAC protocol reduces energy consumption while reducing network latency and improving network throughput.