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Open AccessEditorial

Wireless Sensor Technologies and Applications

by Feng Xia

Sensors 2009, 9(11), 8824-8830; https://doi.org/10.3390/s91108824 - 4 Nov 2009

Cited by 30 | Viewed by 27775

Abstract

Recent years have witnessed tremendous advances in the design and applications of wirelessly networked and embedded sensors. Wireless sensor nodes are typically low-cost, low-power, small devices equipped with limited sensing, data processing and wireless communication capabilities, as well as power supplies. They leverage [...] Read more.

Recent years have witnessed tremendous advances in the design and applications of wirelessly networked and embedded sensors. Wireless sensor nodes are typically low-cost, low-power, small devices equipped with limited sensing, data processing and wireless communication capabilities, as well as power supplies. They leverage the concept of wireless sensor networks (WSNs), in which a large (possibly huge) number of collaborative sensor nodes could be deployed. As an outcome of the convergence of micro-electro-mechanical systems (MEMS) technology, wireless communications, and digital electronics, WSNs represent a significant improvement over traditional sensors. In fact, the rapid evolution of WSN technology has accelerated the development and deployment of various novel types of wireless sensors, e.g., multimedia sensors. Fulfilling Moore’s law, wireless sensors are becoming smaller and cheaper, and at the same time more powerful and ubiquitous. [...] Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Research

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357 KiB

Open AccessArticle

Feedback Power Control Strategies inWireless Sensor Networks with Joint Channel Decoding

by Andrea Abrardo, Gianluigi Ferrari, Marco Martalò and Fabio Perna

Sensors 2009, 9(11), 8776-8809; https://doi.org/10.3390/s91108776 - 3 Nov 2009

Cited by 4 | Viewed by 15363

Abstract

In this paper, we derive feedback power control strategies for block-faded multiple access schemes with correlated sources and joint channel decoding (JCD). In particular, upon the derivation of the feasible signal-to-noise ratio (SNR) region for the considered multiple access schemes, i.e., the multidimensional [...] Read more.

In this paper, we derive feedback power control strategies for block-faded multiple access schemes with correlated sources and joint channel decoding (JCD). In particular, upon the derivation of the feasible signal-to-noise ratio (SNR) region for the considered multiple access schemes, i.e., the multidimensional SNR region where error-free communications are, in principle, possible, two feedback power control strategies are proposed: (i) a classical feedback power control strategy, which aims at equalizing all link SNRs at the access point (AP), and (ii) an innovative optimized feedback power control strategy, which tries to make the network operational point fall in the feasible SNR region at the lowest overall transmit energy consumption. These strategies will be referred to as “balanced SNR” and “unbalanced SNR,” respectively. While they require, in principle, an unlimited power control range at the sources, we also propose practical versions with a limited power control range. We preliminary consider a scenario with orthogonal links and ideal feedback. Then, we analyze the robustness of the proposed power control strategies to possible non-idealities, in terms of residual multiple access interference and noisy feedback channels. Finally, we successfully apply the proposed feedback power control strategies to a limiting case of the class of considered multiple access schemes, namely a central estimating officer (CEO) scenario, where the sensors observe noisy versions of a common binary information sequence and the AP’s goal is to estimate this sequence by properly fusing the soft-output information output by the JCD algorithm. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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350 KiB

Open AccessArticle

Efficient Aggregation of Multiple Classes of Information in Wireless Sensor Networks

by Xiaoling Qiu, Haiping Liu, Deshi Li, Jennifer Yick, Dipak Ghosal and Biswanath Mukherjee

Sensors 2009, 9(10), 8083-8108; https://doi.org/10.3390/s91008083 - 14 Oct 2009

Cited by 11 | Viewed by 16651

Abstract

Congestion in a Wireless Sensor Network (WSN) can lead to buffer overflow, resource waste and delay or loss of critical information from the sensors. In this paper, we propose the Priority-based Coverage-aware Congestion Control (PCC) algorithm which is distributed, priority-distinct, and [...] Read more.

Congestion in a Wireless Sensor Network (WSN) can lead to buffer overflow, resource waste and delay or loss of critical information from the sensors. In this paper, we propose the Priority-based Coverage-aware Congestion Control (PCC) algorithm which is distributed, priority-distinct, and fair. PCC provides higher priority to packets with event information in which the sink is more interested. PCC employs a queue scheduler that can selectively drop any packet in the queue. PCC gives fair chance to all sensors to send packets to the sink, irrespective of their specific locations, and therefore enhances the coverage fidelity of theWSN. Based on a detailed simulation analysis, we show that PCC can efficiently relieve congestion and significantly improve the system performance based on multiple metrics such as event throughput and coverage fidelity. We generalize PCC to address data collection in a WSN in which the sensor nodes have multiple sensing devices and can generate multiple types of information. We propose a Pricing System that can under congestion effectively collect different types of data generated by the sensor nodes according to values that are placed on different information by the sink. Simulation analysis show that our Pricing System can achieve higher event throughput for packets with higher priority and achieve fairness among different categories. Moreover, given a fixed system capacity, our proposed Pricing System can collect more information of the type valued by the sink. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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2584 KiB

Open AccessArticle

A Unified Multi-Functional Dynamic Spectrum Access Framework: Tutorial, Theory and Multi-GHz Wideband Testbed

by Robert Qiu, Nan Guo, Husheng Li, Zhiqiang Wu, Vasu Chakravarthy, Yu Song, Zhen Hu, Peng Zhang and Zhe Chen

Sensors 2009, 9(8), 6530-6603; https://doi.org/10.3390/s90806530 - 21 Aug 2009

Cited by 19 | Viewed by 20012 | Correction

Abstract

Dynamic spectrum access is a must-have ingredient for future sensors that are ideally cognitive. The goal of this paper is a tutorial treatment of wideband cognitive radio and radar—a convergence of (1) algorithms survey, (2) hardware platforms survey, (3) challenges for multi-function (radar/communications) [...] Read more.

Dynamic spectrum access is a must-have ingredient for future sensors that are ideally cognitive. The goal of this paper is a tutorial treatment of wideband cognitive radio and radar—a convergence of (1) algorithms survey, (2) hardware platforms survey, (3) challenges for multi-function (radar/communications) multi-GHz front end, (4) compressed sensing for multi-GHz waveforms—revolutionary A/D, (5) machine learning for cognitive radio/radar, (6) quickest detection, and (7) overlay/underlay cognitive radio waveforms. One focus of this paper is to address the multi-GHz front end, which is the challenge for the next-generation cognitive sensors. The unifying theme of this paper is to spell out the convergence for cognitive radio, radar, and anti-jamming. Moore’s law drives the system functions into digital parts.From a system viewpoint, this paper gives the first comprehensive treatment for the functions and the challenges of this multi-function (wideband) system. This paper brings together the inter-disciplinary knowledge. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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653 KiB

Open AccessArticle

Design of a Water Environment Monitoring System Based on Wireless Sensor Networks

by Peng Jiang, Hongbo Xia, Zhiye He and Zheming Wang

Sensors 2009, 9(8), 6411-6434; https://doi.org/10.3390/s90806411 - 19 Aug 2009

Cited by 195 | Viewed by 25881

Abstract

A water environmental monitoring system based on a wireless sensor network is proposed. It consists of three parts: data monitoring nodes, data base station and remote monitoring center. This system is suitable for the complex and large-scale water environment monitoring, such as for [...] Read more.

A water environmental monitoring system based on a wireless sensor network is proposed. It consists of three parts: data monitoring nodes, data base station and remote monitoring center. This system is suitable for the complex and large-scale water environment monitoring, such as for reservoirs, lakes, rivers, swamps, and shallow or deep groundwaters. This paper is devoted to the explanation and illustration for our new water environment monitoring system design. The system had successfully accomplished the online auto-monitoring of the water temperature and pH value environment of an artificial lake. The system's measurement capacity ranges from 0 to 80 °C for water temperature, with an accuracy of ±0.5 °C; from 0 to 14 on pH value, with an accuracy of ±0.05 pH units. Sensors applicable to different water quality scenarios should be installed at the nodes to meet the monitoring demands for a variety of water environments and to obtain different parameters. The monitoring system thus promises broad applicability prospects. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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1272 KiB

Open AccessArticle

High-Resolution Images with Minimum Energy Dissipation and Maximum Field-of-View in Camera-Based Wireless Multimedia Sensor Networks

by Hadi S. Aghdasi, Pouya Bisadi, Mohsen Ebrahimi Moghaddam and Maghsoud Abbaspour

Sensors 2009, 9(8), 6385-6410; https://doi.org/10.3390/s90806385 - 19 Aug 2009

Cited by 10 | Viewed by 14651

Abstract

High-resolution images with wide field of view are important in realizing many applications of wireless multimedia sensor networks. Previous works that generally use multi-tier topology and provide such images by increasing the capabilities of camera sensor nodes lead to an increase in network [...] Read more.

High-resolution images with wide field of view are important in realizing many applications of wireless multimedia sensor networks. Previous works that generally use multi-tier topology and provide such images by increasing the capabilities of camera sensor nodes lead to an increase in network cost. On the other hand, the resulting energy consumption is a considerable issue that has not been seriously considered in previous works. In this paper, high-resolution images with wide field of view are generated without increasing the total cost of network and with minimum energy dissipation. This is achieved by using image stitching in WMSNs, designing a two-tier network topology with new structure, and proposing a camera selection algorithm. In the proposed two-tier structure, low cost camera sensor nodes are used only in the lower-tier and sensor nodes without camera are considered in the upper-tier which decreases total network cost as much as possible. Also, since a simplified image stitching method is implemented and a new algorithm for selecting active nodes is utilized, energy dissipation in the network is decreased by applying the proposed methods. The results of simulations supported the preceding statements. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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310 KiB

Open AccessArticle

Design and Implementation of a SecureWireless Mote-Based Medical Sensor Network

by Kriangsiri Malasri and Lan Wang

Sensors 2009, 9(8), 6273-6297; https://doi.org/10.3390/s90806273 - 11 Aug 2009

Cited by 66 | Viewed by 13508

Abstract

A medical sensor network can wirelessly monitor vital signs of humans, making it useful for long-term health care without sacrificing patient comfort and mobility. For such a network to be viable, its design must protect data privacy and authenticity given that medical data [...] Read more.

A medical sensor network can wirelessly monitor vital signs of humans, making it useful for long-term health care without sacrificing patient comfort and mobility. For such a network to be viable, its design must protect data privacy and authenticity given that medical data are highly sensitive. We identify the unique security challenges of such a sensor network and propose a set of resource-efficient mechanisms to address these challenges. Our solution includes (1) a novel two-tier scheme for verifying the authenticity of patient data, (2) a secure key agreement protocol to set up shared keys between sensor nodes and base stations, and (3) symmetric encryption/decryption for protecting data confidentiality and integrity. We have implemented the proposed mechanisms on a wireless mote platform, and our results confirm their feasibility. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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1585 KiB

Open AccessArticle

LoWMob: Intra-PAN Mobility Support Schemes for 6LoWPAN

by Gargi Bag, Muhammad Taqi Raza, Ki-Hyung Kim and Seung-Wha Yoo

Sensors 2009, 9(7), 5844-5877; https://doi.org/10.3390/s90705844 - 23 Jul 2009

Cited by 65 | Viewed by 14121

Abstract

Mobility in 6LoWPAN (IPv6 over Low Power Personal Area Networks) is being utilized in realizing many applications where sensor nodes, while moving, sense and transmit the gathered data to a monitoring server. By employing IEEE802.15.4 as a baseline for the link layer technology, [...] Read more.

Mobility in 6LoWPAN (IPv6 over Low Power Personal Area Networks) is being utilized in realizing many applications where sensor nodes, while moving, sense and transmit the gathered data to a monitoring server. By employing IEEE802.15.4 as a baseline for the link layer technology, 6LoWPAN implies low data rate and low power consumption with periodic sleep and wakeups for sensor nodes, without requiring them to incorporate complex hardware. Also enabling sensor nodes with IPv6 ensures that the sensor data can be accessed anytime and anywhere from the world. Several existing mobility-related schemes like HMIPv6, MIPv6, HAWAII, and Cellular IP require active participation of mobile nodes in the mobility signaling, thus leading to the mobility-related changes in the protocol stack of mobile nodes. In this paper, we present LoWMob, which is a network-based mobility scheme for mobile 6LoWPAN nodes in which the mobility of 6LoWPAN nodes is handled at the network-side. LoWMob ensures multi-hop communication between gateways and mobile nodes with the help of the static nodes within a 6LoWPAN. In order to reduce the signaling overhead of static nodes for supporting mobile nodes, LoWMob proposes a mobility support packet format at the adaptation layer of 6LoWPAN. Also we present a distributed version of LoWMob, named as DLoWMob (or Distributed LoWMob), which employs Mobility Support Points (MSPs) to distribute the traffic concentration at the gateways and to optimize the multi-hop routing path between source and destination nodes in a 6LoWPAN. Moreover, we have also discussed the security considerations for our proposed mobility schemes. The performance of our proposed schemes is evaluated in terms of mobility signaling costs, end-to-end delay, and packet success ratio. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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1436 KiB

Open AccessArticle

Adjacency Matrix-Based Transmit Power Allocation Strategies in Wireless Sensor Networks

by Luca Consolini, Paolo Medagliani and Gianluigi Ferrari

Sensors 2009, 9(7), 5390-5422; https://doi.org/10.3390/s90705390 - 9 Jul 2009

Cited by 7 | Viewed by 12286

Abstract

In this paper, we present an innovative transmit power control scheme, based on optimization theory, for wireless sensor networks (WSNs) which use carrier sense multiple access (CSMA) with collision avoidance (CA) as medium access control (MAC) protocol. In particular, we focus on schemes [...] Read more.

In this paper, we present an innovative transmit power control scheme, based on optimization theory, for wireless sensor networks (WSNs) which use carrier sense multiple access (CSMA) with collision avoidance (CA) as medium access control (MAC) protocol. In particular, we focus on schemes where several remote nodes send data directly to a common access point (AP). Under the assumption of finite overall network transmit power and low traffic load, we derive the optimal transmit power allocation strategy that minimizes the packet error rate (PER) at the AP. This approach is based on modeling the CSMA/CA MAC protocol through a finite state machine and takes into account the network adjacency matrix, depending on the transmit power distribution and determining the network connectivity. It will be then shown that the transmit power allocation problem reduces to a convex constrained minimization problem. Our results show that, under the assumption of low traffic load, the power allocation strategy, which guarantees minimal delay, requires the maximization of network connectivity, which can be equivalently interpreted as the maximization of the number of non-zero entries of the adjacency matrix. The obtained theoretical results are confirmed by simulations for unslotted Zigbee WSNs. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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405 KiB

Open AccessArticle

On Connected Target Coverage for Wireless Heterogeneous Sensor Networks with Multiple Sensing Units

by Kuei-Ping Shih, Der-Jiunn Deng, Ruay-Shiung Chang and Hung-Chang Chen

Sensors 2009, 9(7), 5173-5200; https://doi.org/10.3390/s90705173 - 30 Jun 2009

Cited by 30 | Viewed by 12302

Abstract

The paper considers the connected target coverage (CTC) problem in wireless heterogeneous sensor networks (WHSNs) with multiple sensing units, termed MU-CTC problem. MU-CTC problem can be reduced to a connected set cover problem and further formulated as an integer linear programming (ILP) problem. [...] Read more.

The paper considers the connected target coverage (CTC) problem in wireless heterogeneous sensor networks (WHSNs) with multiple sensing units, termed MU-CTC problem. MU-CTC problem can be reduced to a connected set cover problem and further formulated as an integer linear programming (ILP) problem. However, the ILP problem is an NP-complete problem. Therefore, two distributed heuristic schemes, REFS (remaining energy first scheme) and EEFS (energy efficiency first scheme), are proposed. In REFS, each sensor considers its remaining energy and its neighbors’ decisions to enable its sensing units and communication unit such that all targets can be covered for the required attributes and the sensed data can be delivered to the sink. The advantages of REFS are its simplicity and reduced communication overhead. However, to utilize sensors’ energy efficiently, EEFS is proposed. A sensor in EEFS considers its contribution to the coverage and the connectivity to make a better decision. To our best knowledge, this paper is the first to consider target coverage and connectivity jointly for WHSNs with multiple sensing units. Simulation results show that REFS and EEFS can both prolong the network lifetime effectively. EEFS outperforms REFS in network lifetime, but REFS is simpler. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

Selective Attention in Multi-Chip Address-Event Systems

by Chiara Bartolozzi and Giacomo Indiveri

Sensors 2009, 9(7), 5076-5098; https://doi.org/10.3390/s90705076 - 26 Jun 2009

Cited by 30 | Viewed by 11736

Abstract

Selective attention is the strategy used by biological systems to cope with the inherent limits in their available computational resources, in order to efficiently process sensory information. The same strategy can be used in artificial systems that have to process vast amounts of [...] Read more.

Selective attention is the strategy used by biological systems to cope with the inherent limits in their available computational resources, in order to efficiently process sensory information. The same strategy can be used in artificial systems that have to process vast amounts of sensory data with limited resources. In this paper we present a neuromorphic VLSI device, the “Selective Attention Chip” (SAC), which can be used to implement these models in multi-chip address-event systems. We also describe a real-time sensory-motor system, which integrates the SAC with a dynamic vision sensor and a robotic actuator. We present experimental results from each component in the system, and demonstrate how the complete system implements a real-time stimulus-driven selective attention model. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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1087 KiB

Open AccessArticle

On the Relevance of Using OpenWireless Sensor Networks in Environment Monitoring

by Antoine B. Bagula, Gordon Inggs, Simon Scott and Marco Zennaro

Sensors 2009, 9(6), 4845-4868; https://doi.org/10.3390/s90604845 - 19 Jun 2009

Cited by 6 | Viewed by 16478

Abstract

This paper revisits the problem of the readiness for field deployments of wireless- sensor networks by assessing the relevance of using Open Hardware and Software motes for environment monitoring. We propose a new prototype wireless sensor network that finetunes SquidBee motes to improve [...] Read more.

This paper revisits the problem of the readiness for field deployments of wireless- sensor networks by assessing the relevance of using Open Hardware and Software motes for environment monitoring. We propose a new prototype wireless sensor network that finetunes SquidBee motes to improve the life-time and sensing performance of an environment monitoring system that measures temperature, humidity and luminosity. Building upon two outdoor sensing scenarios, we evaluate the performance of the newly proposed energy-aware prototype solution in terms of link quality when expressed by the Received Signal Strength, Packet Loss and the battery lifetime. The experimental results reveal the relevance of using the Open Hardware and Software motes when setting up outdoor wireless sensor networks. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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373 KiB

Open AccessArticle

Medium Access Control for Opportunistic Concurrent Transmissions under Shadowing Channels

by In Keun Son, Shiwen Mao and Seung Min Hur

Sensors 2009, 9(6), 4824-4844; https://doi.org/10.3390/s90604824 - 18 Jun 2009

Cited by 6 | Viewed by 14371

Abstract

We study the problem of how to alleviate the exposed terminal effect in multihop wireless networks in the presence of log-normal shadowing channels. Assuming node location information, we propose an extension of the IEEE 802.11 MAC protocol that schedules concurrent transmissions in the [...] Read more.

We study the problem of how to alleviate the exposed terminal effect in multihop wireless networks in the presence of log-normal shadowing channels. Assuming node location information, we propose an extension of the IEEE 802.11 MAC protocol that schedules concurrent transmissions in the presence of log-normal shadowing, thus mitigating the exposed terminal problem and improving network throughput and delay performance. We observe considerable improvements in throughput and delay achieved over the IEEE 802.11 MAC under various network topologies and channel conditions in ns-2 simulations, which justify the importance of considering channel randomness in MAC protocol design for multihop wireless networks. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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282 KiB

Open AccessArticle

Secure Cluster Head Sensor Elections Using Signal Strength Estimation and Ordered Transmissions

by Gicheol Wang and Gihwan Cho

Sensors 2009, 9(6), 4709-4727; https://doi.org/10.3390/s90604709 - 16 Jun 2009

Cited by 10 | Viewed by 15051

Abstract

In clustered sensor networks, electing CHs (Cluster Heads) in a secure manner is very important because they collect data from sensors and send the aggregated data to the sink. If a compromised node is elected as a CH, it can illegally acquire data [...] Read more.

In clustered sensor networks, electing CHs (Cluster Heads) in a secure manner is very important because they collect data from sensors and send the aggregated data to the sink. If a compromised node is elected as a CH, it can illegally acquire data from all the members and even send forged data to the sink. Nevertheless, most of the existing CH election schemes have not treated the problem of the secure CH election. Recently, random value based protocols have been proposed to resolve the secure CH election problem. However, these schemes cannot prevent an attacker from suppressing its contribution for the change of CH election result and from selectively forwarding its contribution for the disagreement of CH election result. In this paper, we propose a modified random value scheme to prevent these disturbances. Our scheme dynamically adjusts the forwarding order of contributions and discards a received contribution when its signal strength is lower than the specified level to prevent these malicious actions. The simulation results have shown that our scheme effectively prevents attackers from changing and splitting an agreement of CH election result. Also, they have shown that our scheme is relatively energy-efficient than other schemes. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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938 KiB

Open AccessArticle

Design and Evaluation of a Wireless Sensor Network Based Aircraft Strength Testing System

by Jian Wu, Shenfang Yuan, Genyuan Zhou, Sai Ji, Zilong Wang and Yang Wang

Sensors 2009, 9(6), 4195-4210; https://doi.org/10.3390/s90604195 - 3 Jun 2009

Cited by 36 | Viewed by 18148

Abstract

The verification of aerospace structures, including full-scale fatigue and static test programs, is essential for structure strength design and evaluation. However, the current overall ground strength testing systems employ a large number of wires for communication among sensors and data acquisition facilities. The [...] Read more.

The verification of aerospace structures, including full-scale fatigue and static test programs, is essential for structure strength design and evaluation. However, the current overall ground strength testing systems employ a large number of wires for communication among sensors and data acquisition facilities. The centralized data processing makes test programs lack efficiency and intelligence. Wireless sensor network (WSN) technology might be expected to address the limitations of cable-based aeronautical ground testing systems. This paper presents a wireless sensor network based aircraft strength testing (AST) system design and its evaluation on a real aircraft specimen. In this paper, a miniature, high-precision, and shock-proof wireless sensor node is designed for multi-channel strain gauge signal conditioning and monitoring. A cluster-star network topology protocol and application layer interface are designed in detail. To verify the functionality of the designed wireless sensor network for strength testing capability, a multi-point WSN based AST system is developed for static testing of a real aircraft undercarriage. Based on the designed wireless sensor nodes, the wireless sensor network is deployed to gather, process, and transmit strain gauge signals and monitor results under different static test loads. This paper shows the efficiency of the wireless sensor network based AST system, compared to a conventional AST system. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

Dynamic Hierarchical Sleep Scheduling for Wireless Ad-Hoc Sensor Networks

by Chih-Yu Wen and Ying-Chih Chen

Sensors 2009, 9(5), 3908-3941; https://doi.org/10.3390/s90503908 - 25 May 2009

Cited by 7 | Viewed by 11368

Abstract

This paper presents two scheduling management schemes for wireless sensor networks, which manage the sensors by utilizing the hierarchical network structure and allocate network resources efficiently. A local criterion is used to simultaneously establish the sensing coverage and connectivity such that dynamic cluster-based [...] Read more.

This paper presents two scheduling management schemes for wireless sensor networks, which manage the sensors by utilizing the hierarchical network structure and allocate network resources efficiently. A local criterion is used to simultaneously establish the sensing coverage and connectivity such that dynamic cluster-based sleep scheduling can be achieved. The proposed schemes are simulated and analyzed to abstract the network behaviors in a number of settings. The experimental results show that the proposed algorithms provide efficient network power control and can achieve high scalability in wireless sensor networks. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

A Hybrid Stochastic Approach for Self-Location of Wireless Sensors in Indoor Environments

by Jaime Lloret, Jesus Tomas, Miguel Garcia and Alejandro Canovas

Sensors 2009, 9(5), 3695-3712; https://doi.org/10.3390/s90503695 - 15 May 2009

Cited by 55 | Viewed by 13972

Abstract

Indoor location systems, especially those using wireless sensor networks, are used in many application areas. While the need for these systems is widely proven, there is a clear lack of accuracy. Many of the implemented applications have high errors in their location estimation [...] Read more.

Indoor location systems, especially those using wireless sensor networks, are used in many application areas. While the need for these systems is widely proven, there is a clear lack of accuracy. Many of the implemented applications have high errors in their location estimation because of the issues arising in the indoor environment. Two different approaches had been proposed using WLAN location systems: on the one hand, the so-called deductive methods take into account the physical properties of signal propagation. These systems require a propagation model, an environment map, and the position of the radio-stations. On the other hand, the so-called inductive methods require a previous training phase where the system learns the received signal strength (RSS) in each location. This phase can be very time consuming. This paper proposes a new stochastic approach which is based on a combination of deductive and inductive methods whereby wireless sensors could determine their positions using WLAN technology inside a floor of a building. Our goal is to reduce the training phase in an indoor environment, but, without an loss of precision. Finally, we compare the measurements taken using our proposed method in a real environment with the measurements taken by other developed systems. Comparisons between the proposed system and other hybrid methods are also provided. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

Monitoring Animal Behaviour and Environmental Interactions Using Wireless Sensor Networks, GPS Collars and Satellite Remote Sensing

by Rebecca N. Handcock, Dave L. Swain, Greg J. Bishop-Hurley, Kym P. Patison, Tim Wark, Philip Valencia, Peter Corke and Christopher J. O’Neill

Sensors 2009, 9(5), 3586-3603; https://doi.org/10.3390/s90503586 - 13 May 2009

Cited by 253 | Viewed by 37173

Abstract

Remote monitoring of animal behaviour in the environment can assist in managing both the animal and its environmental impact. GPS collars which record animal locations with high temporal frequency allow researchers to monitor both animal behaviour and interactions with the environment. These ground-based [...] Read more.

Remote monitoring of animal behaviour in the environment can assist in managing both the animal and its environmental impact. GPS collars which record animal locations with high temporal frequency allow researchers to monitor both animal behaviour and interactions with the environment. These ground-based sensors can be combined with remotely-sensed satellite images to understand animal-landscape interactions. The key to combining these technologies is communication methods such as wireless sensor networks (WSNs). We explore this concept using a case-study from an extensive cattle enterprise in northern Australia and demonstrate the potential for combining GPS collars and satellite images in a WSN to monitor behavioural preferences and social behaviour of cattle. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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313 KiB

Open AccessArticle

Deployment Design of Wireless Sensor Network for Simple Multi-Point Surveillance of a Moving Target

by Kazuya Tsukamoto, Hirofumi Ueda, Hitomi Tamura, Kenji Kawahara and Yuji Oie

Sensors 2009, 9(5), 3563-3585; https://doi.org/10.3390/s90503563 - 13 May 2009

Cited by 7 | Viewed by 12039

Abstract

In this paper, we focus on the problem of tracking a moving target in a wireless sensor network (WSN), in which the capability of each sensor is relatively limited, to construct large-scale WSNs at a reasonable cost. We first propose two simple multi-point [...] Read more.

In this paper, we focus on the problem of tracking a moving target in a wireless sensor network (WSN), in which the capability of each sensor is relatively limited, to construct large-scale WSNs at a reasonable cost. We first propose two simple multi-point surveillance schemes for a moving target in a WSN and demonstrate that one of the schemes can achieve high tracking probability with low power consumption. In addition, we examine the relationship between tracking probability and sensor density through simulations, and then derive an approximate expression representing the relationship. As the results, we present guidelines for sensor density, tracking probability, and the number of monitoring sensors that satisfy a variety of application demands. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

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

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

Sensors 2009, 9(5), 3447-3468; https://doi.org/10.3390/s90503447 - 11 May 2009

Cited by 37 | Viewed by 14374

Abstract

TheIP-based Ubiquitous Sensor Network (IP-USN) is an effort to build the “Internet of things”. By utilizing IP for low power networks, we can benefit from existing well established tools and technologies of IP networks. Along with many other unresolved issues, securing IP-USN is [...] Read more.

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

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

Determining the Best Sensing Coverage for 2-Dimensional Acoustic Target Tracking

by Saeid Pashazadeh and Mohsen Sharifi

Sensors 2009, 9(5), 3405-3436; https://doi.org/10.3390/s90503405 - 8 May 2009

Cited by 9 | Viewed by 11987

Abstract

Distributed acoustic target tracking is an important application area of wireless sensor networks. In this paper we use algebraic geometry to formally model 2-dimensional acoustic target tracking and then prove its best degree of required sensing coverage. We present the necessary conditions for [...] Read more.

Distributed acoustic target tracking is an important application area of wireless sensor networks. In this paper we use algebraic geometry to formally model 2-dimensional acoustic target tracking and then prove its best degree of required sensing coverage. We present the necessary conditions for three sensing coverage to accurately compute the spatio-temporal information of a target object. Simulations show that 3-coverage accurately locates a target object only in 53% of cases. Using 4-coverage, we present two different methods that yield correct answers in almost all cases and have time and memory usage complexity of Θ(1). Analytic 4-coverage tracking is our first proposed method that solves a simultaneous equation system using the sensing information of four sensor nodes. Redundant answer fusion is our second proposed method that solves at least two sets of simultaneous equations of target tracking using the sensing information of two different sets of three sensor nodes, and fusing the results using a new customized formal majority voter. We prove that 4-coverage guarantees accurate 2-dimensional acoustic target tracking under ideal conditions. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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1418 KiB

Open AccessArticle

Development of a Sensor Node for Precision Horticulture

by Juan A. López, Fulgencio Soto, Pedro Sánchez, Andrés Iborra, Juan Suardiaz and Juan A. Vera

Sensors 2009, 9(5), 3240-3255; https://doi.org/10.3390/s90503240 - 28 Apr 2009

Cited by 30 | Viewed by 20350

Abstract

This paper presents the design of a new wireless sensor node (GAIA Soil-Mote) for precision horticulture applications which permits the use of precision agricultural instruments based on the SDI-12 standard. Wireless communication is achieved with a transceiver compliant with the IEEE 802.15.4 standard. [...] Read more.

This paper presents the design of a new wireless sensor node (GAIA Soil-Mote) for precision horticulture applications which permits the use of precision agricultural instruments based on the SDI-12 standard. Wireless communication is achieved with a transceiver compliant with the IEEE 802.15.4 standard. The GAIA Soil-Mote software implementation is based on TinyOS. A two-phase methodology was devised to validate the design of this sensor node. The first phase consisted of laboratory validation of the proposed hardware and software solution, including a study on power consumption and autonomy. The second phase consisted of implementing a monitoring application in a real broccoli (Brassica oleracea L. var Marathon) crop in Campo de Cartagena in south-east Spain. In this way the sensor node was validated in real operating conditions. This type of application was chosen because there is a large potential market for it in the farming sector, especially for the development of precision agriculture applications. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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803 KiB

Open AccessArticle

Anchor-Free Localization Method for Mobile Targets in Coal Mine Wireless Sensor Networks

by Zhongmin Pei, Zhidong Deng, Shuo Xu and Xiao Xu

Sensors 2009, 9(4), 2836-2850; https://doi.org/10.3390/s90402836 - 21 Apr 2009

Cited by 43 | Viewed by 16540

Abstract

Severe natural conditions and complex terrain make it difficult to apply precise localization in underground mines. In this paper, an anchor-free localization method for mobile targets is proposed based on non-metric multi-dimensional scaling (Multi-dimensional Scaling: MDS) and rank sequence. Firstly, a coal mine [...] Read more.

Severe natural conditions and complex terrain make it difficult to apply precise localization in underground mines. In this paper, an anchor-free localization method for mobile targets is proposed based on non-metric multi-dimensional scaling (Multi-dimensional Scaling: MDS) and rank sequence. Firstly, a coal mine wireless sensor network is constructed in underground mines based on the ZigBee technology. Then a non-metric MDS algorithm is imported to estimate the reference nodes’ location. Finally, an improved sequence-based localization algorithm is presented to complete precise localization for mobile targets. The proposed method is tested through simulations with 100 nodes, outdoor experiments with 15 ZigBee physical nodes, and the experiments in the mine gas explosion laboratory with 12 ZigBee nodes. Experimental results show that our method has better localization accuracy and is more robust in underground mines. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

A Novel Intra-body Sensor for Vaginal Temperature Monitoring

by Joel J. P. C. Rodrigues, João Caldeira and Binod Vaidya

Sensors 2009, 9(4), 2797-2808; https://doi.org/10.3390/s90402797 - 21 Apr 2009

Cited by 24 | Viewed by 20333

Abstract

Over the years some medical studies have tried to better understand the internal behavior of human beings. Many researchers in this domain have been striving to find relationships between intra-vaginal temperature and certain female health conditions, such as ovulation and fertile period since [...] Read more.

Over the years some medical studies have tried to better understand the internal behavior of human beings. Many researchers in this domain have been striving to find relationships between intra-vaginal temperature and certain female health conditions, such as ovulation and fertile period since woman’s intra-vaginal temperature is one of the body parameters most preferred in such studies. However, due to lack of a appropriate technology, medical research devoted to studying correlations of such body parameters with certain womans’ body phenomena could not obtain better results. This article presents the design and implementation of a novel intra-body sensor for acquisition and monitoring of intra-vaginal temperatures. This novel intra-body sensor provides data collection that is used for studying the relation between temperature variations and female health conditions, such as anticipation and monitoring of the ovulation period, detection of pregnancy contractions, preterm labor prevention, etc.. The motivation for this work focuses on the development of this new intra-body sensor that will represent a major step in medical technology. The novel sensor was tested and validated on hospitalized women as well as normal healthy women. Finally our medical team has attested to the accuracy, usability and performance of this novel intra-body sensor. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

Adapting Mobile Beacon-Assisted Localization in Wireless Sensor Networks

by Guodong Teng, Kougen Zheng and Wei Dong

Sensors 2009, 9(4), 2760-2779; https://doi.org/10.3390/s90402760 - 20 Apr 2009

Cited by 27 | Viewed by 16230

Abstract

The ability to automatically locate sensor nodes is essential in many Wireless Sensor Network (WSN) applications. To reduce the number of beacons, many mobile-assisted approaches have been proposed. Current mobile-assisted approaches for localization require special hardware or belong to centralized localization algorithms involving [...] Read more.

The ability to automatically locate sensor nodes is essential in many Wireless Sensor Network (WSN) applications. To reduce the number of beacons, many mobile-assisted approaches have been proposed. Current mobile-assisted approaches for localization require special hardware or belong to centralized localization algorithms involving some deterministic approaches due to the fact that they explicitly consider the impreciseness of location estimates. In this paper, we first propose a range-free, distributed and probabilistic Mobile Beacon-assisted Localization (MBL) approach for static WSNs. Then, we propose another approach based on MBL, called Adapting MBL (A-MBL), to increase the efficiency and accuracy of MBL by adapting the size of sample sets and the parameter of the dynamic model during the estimation process. Evaluation results show that the accuracy of MBL and A-MBL outperform both Mobile and Static sensor network Localization (MSL) and Arrival and Departure Overlap (ADO) when both of them use only a single mobile beacon for localization in static WSNs. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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367 KiB

Open AccessArticle

Availability and End-to-end Reliability in Low Duty Cycle MultihopWireless Sensor Networks

by Jukka Suhonen, Timo D. Hämäläinen and Marko Hännikäinen

Sensors 2009, 9(3), 2088-2116; https://doi.org/10.3390/s90302088 - 20 Mar 2009

Cited by 24 | Viewed by 16435

Abstract

A wireless sensor network (WSN) is an ad-hoc technology that may even consist of thousands of nodes, which necessitates autonomic, self-organizing and multihop operations. A typical WSN node is battery powered, which makes the network lifetime the primary concern. The highest energy efficiency [...] Read more.

A wireless sensor network (WSN) is an ad-hoc technology that may even consist of thousands of nodes, which necessitates autonomic, self-organizing and multihop operations. A typical WSN node is battery powered, which makes the network lifetime the primary concern. The highest energy efficiency is achieved with low duty cycle operation, however, this alone is not enough. WSNs are deployed for different uses, each requiring acceptable Quality of Service (QoS). Due to the unique characteristics of WSNs, such as dynamic wireless multihop routing and resource constraints, the legacy QoS metrics are not feasible as such. We give a new definition to measure and implement QoS in low duty cycle WSNs, namely availability and reliability. Then, we analyze the effect of duty cycling for reaching the availability and reliability. The results are obtained by simulations with ZigBee and proprietary TUTWSN protocols. Based on the results, we also propose a data forwarding algorithm suitable for resource constrained WSNs that guarantees end-to-end reliability while adding a small overhead that is relative to the packet error rate (PER). The forwarding algorithm guarantees reliability up to 30% PER. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

Spatial Forecast of Landslides in Three Gorges Based On Spatial Data Mining

by Xianmin Wang and Ruiqing Niu

Sensors 2009, 9(3), 2035-2061; https://doi.org/10.3390/s90302035 - 18 Mar 2009

Cited by 52 | Viewed by 17062

Abstract

The Three Gorges is a region with a very high landslide distribution density and a concentrated population. In Three Gorges there are often landslide disasters, and the potential risk of landslides is tremendous. In this paper, focusing on Three Gorges, which has a [...] Read more.

The Three Gorges is a region with a very high landslide distribution density and a concentrated population. In Three Gorges there are often landslide disasters, and the potential risk of landslides is tremendous. In this paper, focusing on Three Gorges, which has a complicated landform, spatial forecasting of landslides is studied by establishing 20 forecast factors (spectra, texture, vegetation coverage, water level of reservoir, slope structure, engineering rock group, elevation, slope, aspect, etc). China-Brazil Earth Resources Satellite (Cbers) images were adopted based on C4.5 decision tree to mine spatial forecast landslide criteria in Guojiaba Town (Zhigui County) in Three Gorges and based on this knowledge, perform intelligent spatial landslide forecasts for Guojiaba Town. All landslides lie in the dangerous and unstable regions, so the forecast result is good. The method proposed in the paper is compared with seven other methods: IsoData, K-Means, Mahalanobis Distance, Maximum Likelihood, Minimum Distance, Parallelepiped and Information Content Model. The experimental results show that the method proposed in this paper has a high forecast precision, noticeably higher than that of the other seven methods. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

A Tabu Search WSN Deployment Method for Monitoring Geographically Irregular Distributed Events

by Nadjib Aitsaadi, Nadjib Achir, Khaled Boussetta and Guy Pujolle

Sensors 2009, 9(3), 1625-1643; https://doi.org/10.3390/s90301625 - 9 Mar 2009

Cited by 41 | Viewed by 13868

Abstract

In this paper, we address the Wireless Sensor Network (WSN) deployment issue. We assume that the observed area is characterized by the geographical irregularity of the sensed events. Formally, we consider that each point in the deployment area is associated a differentiated detection [...] Read more.

In this paper, we address the Wireless Sensor Network (WSN) deployment issue. We assume that the observed area is characterized by the geographical irregularity of the sensed events. Formally, we consider that each point in the deployment area is associated a differentiated detection probability threshold, which must be satisfied by our deployment method. Our resulting WSN deployment problem is formulated as a Multi-Objectives Optimization problem, which seeks to reduce the gap between the generated events detection probabilities and the required thresholds while minimizing the number of deployed sensors. To overcome the computational complexity of an exact resolution, we propose an original pseudo-random approach based on the Tabu Search heuristic. Simulations show that our proposal achieves better performances than several other approaches proposed in the literature. In the last part of this paper, we generalize the deployment problem by including the wireless communication network connectivity constraint. Thus, we extend our proposal to ensure that the resulting WSN topology is connected even if a sensor communication range takes small values. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

A Novel Energy-Efficient MAC Aware Data Aggregation Routing in Wireless Sensor Networks ^#

by Frank Yeong-Sung Lin, Hong-Hsu Yen and Shu-Ping Lin

Sensors 2009, 9(3), 1518-1533; https://doi.org/10.3390/s90301518 - 4 Mar 2009

Cited by 13 | Viewed by 15135

Abstract

Embedding data-aggregation capabilities into sensor nodes of wireless networks could save energy by reducing redundant data flow transmissions. Existing research describes the construction of data aggregation trees to maximize data aggregation times in order to reduce data transmission of redundant data. However, aggregation [...] Read more.

Embedding data-aggregation capabilities into sensor nodes of wireless networks could save energy by reducing redundant data flow transmissions. Existing research describes the construction of data aggregation trees to maximize data aggregation times in order to reduce data transmission of redundant data. However, aggregation of more nodes on the same node will incur significant collisions. These MAC (Media Access Control) layer collisions introduce additional data retransmissions that could jeopardize the advantages of data aggregation. This paper is the first to consider the energy consumption tradeoffs between data aggregation and retransmissions in a wireless sensor network. By using the existing CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) MAC protocol, the retransmission energy consumption function is well formulated. This paper proposes a novel non-linear mathematical formulation, whose function is to minimize the total energy consumption of data transmission subject to data aggregation trees and data retransmissions. This solution approach is based on Lagrangean relaxation, in conjunction with optimization-based heuristics. From the computational experiments, it is shown that the proposed algorithms could construct MAC aware data aggregation trees that are up to 59% more energy efficient than existing data aggregation algorithms. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

Detection of Activities by Wireless Sensors for Daily Life Surveillance: Eating and Drinking

by Sen Zhang, Marcelo H. Ang, Jr., Wendong Xiao and Chen Khong Tham

Sensors 2009, 9(3), 1499-1517; https://doi.org/10.3390/s90301499 - 3 Mar 2009

Cited by 56 | Viewed by 15382

Abstract

This paper introduces a two-stage approach to the detection of people eating and/or drinking for the purposes of surveillance of daily life. With the sole use of wearable accelerometer sensor attached to somebody’s (man or a woman) wrists, this two-stage approach consists of [...] Read more.

This paper introduces a two-stage approach to the detection of people eating and/or drinking for the purposes of surveillance of daily life. With the sole use of wearable accelerometer sensor attached to somebody’s (man or a woman) wrists, this two-stage approach consists of feature extraction followed by classification. At the first stage, based on the limb’s three dimensional kinematics movement model and the Extended Kalman Filter (EKF), the realtime arm movement features described by Euler angles are extracted from the raw accelerometer measurement data. In the latter stage, the Hierarchical Temporal Memory (HTM) network is adopted to classify the extracted features of the eating/drinking activities based on the space and time varying property of the features, by making use of the powerful modelling capability of HTM network on dynamic signals which is varying with both space and time. The proposed approach is tested through the real eating and drinking activities using the three dimensional accelerometers. Experimental results show that the EKF and HTM based two-stage approach can perform the activity detection successfully with very high accuracy. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

Sink-oriented Dynamic Location Service Protocol for Mobile Sinks with an Energy Efficient Grid-Based Approach

by Hyeonjae Jeon, Kwangjin Park, Dae-Joon Hwang and Hyunseung Choo

Sensors 2009, 9(3), 1433-1453; https://doi.org/10.3390/s90301433 - 3 Mar 2009

Cited by 22 | Viewed by 16266

Abstract

Sensor nodes transmit the sensed information to the sink through wireless sensor networks (WSNs). They have limited power, computational capacities and memory. Portable wireless devices are increasing in popularity. Mechanisms that allow information to be efficiently obtained through mobile WSNs are of significant [...] Read more.

Sensor nodes transmit the sensed information to the sink through wireless sensor networks (WSNs). They have limited power, computational capacities and memory. Portable wireless devices are increasing in popularity. Mechanisms that allow information to be efficiently obtained through mobile WSNs are of significant interest. However, a mobile sink introduces many challenges to data dissemination in large WSNs. For example, it is important to efficiently identify the locations of mobile sinks and disseminate information from multi-source nodes to the multi-mobile sinks. In particular, a stationary dissemination path may no longer be effective in mobile sink applications, due to sink mobility. In this paper, we propose a Sink-oriented Dynamic Location Service (SDLS) approach to handle sink mobility. In SDLS, we propose an Eight-Direction Anchor (EDA) system that acts as a location service server. EDA prevents intensive energy consumption at the border sensor nodes and thus provides energy balancing to all the sensor nodes. Then we propose a Location-based Shortest Relay (LSR) that efficiently forwards (or relays) data from a source node to a sink with minimal delay path. Our results demonstrate that SDLS not only provides an efficient and scalable location service, but also reduces the average data communication overhead in scenarios with multiple and moving sinks and sources. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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201 KiB

Open AccessArticle

A New Method for Node Fault Detection in Wireless Sensor Networks

by Peng Jiang

Sensors 2009, 9(2), 1282-1294; https://doi.org/10.3390/s90201282 - 24 Feb 2009

Cited by 163 | Viewed by 16176

Abstract

Wireless sensor networks (WSNs) are an important tool for monitoring distributed remote environments. As one of the key technologies involved in WSNs, node fault detection is indispensable in most WSN applications. It is well known that the distributed fault detection (DFD) scheme checks [...] Read more.

Wireless sensor networks (WSNs) are an important tool for monitoring distributed remote environments. As one of the key technologies involved in WSNs, node fault detection is indispensable in most WSN applications. It is well known that the distributed fault detection (DFD) scheme checks out the failed nodes by exchanging data and mutually testing among neighbor nodes in this network., but the fault detection accuracy of a DFD scheme would decrease rapidly when the number of neighbor nodes to be diagnosed is small and the node’s failure ratio is high. In this paper, an improved DFD scheme is proposed by defining new detection criteria. Simulation results demonstrate that the improved DFD scheme performs well in the above situation and can increase the fault detection accuracy greatly. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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341 KiB

Open AccessArticle

Energy Efficient Sensor Scheduling with a Mobile Sink Node for the Target Tracking Application

by Suhinthan Maheswararajah, Saman Halgamuge and Malin Premaratne

Sensors 2009, 9(2), 696-716; https://doi.org/10.3390/s90100696 - 23 Jan 2009

Cited by 8 | Viewed by 11669

Abstract

Measurement losses adversely affect the performance of target tracking. The sensor network’s life span depends on how efficiently the sensor nodes consume energy. In this paper, we focus on minimizing the total energy consumed by the sensor nodes whilst avoiding measurement losses. Since [...] Read more.

Measurement losses adversely affect the performance of target tracking. The sensor network’s life span depends on how efficiently the sensor nodes consume energy. In this paper, we focus on minimizing the total energy consumed by the sensor nodes whilst avoiding measurement losses. Since transmitting data over a long distance consumes a significant amount of energy, a mobile sink node collects the measurements and transmits them to the base station. We assume that the default transmission range of the activated sensor node is limited and it can be increased to maximum range only if the mobile sink node is out-side the default transmission range. Moreover, the active sensor node can be changed after a certain time period. The problem is to select an optimal sensor sequence which minimizes the total energy consumed by the sensor nodes. In this paper, we consider two different problems depend on the mobile sink node’s path. First, we assume that the mobile sink node’s position is known for the entire time horizon and use the dynamic programming technique to solve the problem. Second, the position of the sink node is varied over time according to a known Markov chain, and the problem is solved by stochastic dynamic programming. We also present sub-optimal methods to solve our problem. A numerical example is presented in order to discuss the proposed methods’ performance. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

Wireless Monitoring of Automobile Tires for Intelligent Tires

by Ryosuke Matsuzaki and Akira Todoroki

Sensors 2008, 8(12), 8123-8138; https://doi.org/10.3390/s8128123 - 9 Dec 2008

Cited by 110 | Viewed by 24243

Abstract

This review discusses key technologies of intelligent tires focusing on sensors and wireless data transmission. Intelligent automobile tires, which monitor their pressure, deformation, wheel loading, friction, or tread wear, are expected to improve the reliability of tires and tire control systems. However, in [...] Read more.

This review discusses key technologies of intelligent tires focusing on sensors and wireless data transmission. Intelligent automobile tires, which monitor their pressure, deformation, wheel loading, friction, or tread wear, are expected to improve the reliability of tires and tire control systems. However, in installing sensors in a tire, many problems have to be considered, such as compatibility of the sensors with tire rubber, wireless transmission, and battery installments. As regards sensing, this review discusses indirect methods using existing sensors, such as that for wheel speed, and direct methods, such as surface acoustic wave sensors and piezoelectric sensors. For wireless transmission, passive wireless methods and energy harvesting are also discussed. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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284 KiB

Open AccessArticle

A Passive Wireless Temperature Sensor for Harsh Environment Applications

by Ya Wang, Yi Jia, Qiushui Chen and Yanyun Wang

Sensors 2008, 8(12), 7982-7995; https://doi.org/10.3390/s8127982 - 8 Dec 2008

Cited by 104 | Viewed by 24764

Abstract

High temperature sensors capable of operating in harsh environments are needed in order to prevent disasters caused by structural or system functional failures due to increasing temperatures. Most existing temperature sensors do not satisfy the needs because they require either physical contact or [...] Read more.

High temperature sensors capable of operating in harsh environments are needed in order to prevent disasters caused by structural or system functional failures due to increasing temperatures. Most existing temperature sensors do not satisfy the needs because they require either physical contact or a battery power supply for signal communication, and furthermore, neither of them can withstand high temperatures nor rotating applications. This paper presents a novel passive wireless temperature sensor, suitable for working in harsh environments for high temperature rotating component monitoring. A completely passive LC resonant telemetry scheme, relying on a frequency variation output, which has been applied successfully in pressure, humidity and chemical measurement, is integrated with a unique high-k temperature sensitive ceramic material, in order to measure the temperatures without contacts, active elements, or power supplies within the sensor. In this paper, the high temperature sensor design and performance analysis are conducted based on mechanical and electrical modeling, in order to maximize the sensing distance, the Q factor and the sensitivity. In the end, the sensor prototype is fabricated and calibrated successfully up to 235ºC, so that the concept of temperature sensing through passive wireless communication is proved. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

TinyONet: A Cache-Based Sensor Network Bridge Enabling Sensing Data Reusability and Customized Wireless Sensor Network Services

by Eui-Hyun Jung and Yong-Jin Park

Sensors 2008, 8(12), 7930-7950; https://doi.org/10.3390/s8127930 - 5 Dec 2008

Cited by 5 | Viewed by 13033

Abstract

In recent years, a few protocol bridge research projects have been announced to enable a seamless integration of Wireless Sensor Networks (WSNs) with the TCP/IP network. These studies have ensured the transparent end-to-end communication between two network sides in the node-centric manner. Researchers [...] Read more.

In recent years, a few protocol bridge research projects have been announced to enable a seamless integration of Wireless Sensor Networks (WSNs) with the TCP/IP network. These studies have ensured the transparent end-to-end communication between two network sides in the node-centric manner. Researchers expect this integration will trigger the development of various application domains. However, prior research projects have not fully explored some essential features for WSNs, especially the reusability of sensing data and the data-centric communication. To resolve these issues, we suggested a new protocol bridge system named TinyONet. In TinyONet, virtual sensors play roles as virtual counterparts of physical sensors and they dynamically group to make a functional entity, Slice. Instead of direct interaction with individual physical sensors, each sensor application uses its own WSN service provided by Slices. If a new kind of service is required in TinyONet, the corresponding function can be dynamically added at runtime. Beside the data-centric communication, it also supports the node-centric communication and the synchronous access. In order to show the effectiveness of the system, we implemented TinyONet on an embedded Linux machine and evaluated it with several experimental scenarios. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

An Energy-Efficient Secure Routing and Key Management Scheme for Mobile Sinks in Wireless Sensor Networks Using Deployment Knowledge

by Le Xuan Hung, Ngo Trong Canh, Sungyoung Lee, Young-Koo Lee and Heejo Lee

Sensors 2008, 8(12), 7753-7782; https://doi.org/10.3390/s8127753 - 3 Dec 2008

Cited by 8 | Viewed by 13582

Abstract

For many sensor network applications such as military or homeland security, it is essential for users (sinks) to access the sensor network while they are moving. Sink mobility brings new challenges to secure routing in large-scale sensor networks. Previous studies on sink mobility [...] Read more.

For many sensor network applications such as military or homeland security, it is essential for users (sinks) to access the sensor network while they are moving. Sink mobility brings new challenges to secure routing in large-scale sensor networks. Previous studies on sink mobility have mainly focused on efficiency and effectiveness of data dissemination without security consideration. Also, studies and experiences have shown that considering security during design time is the best way to provide security for sensor network routing. This paper presents an energy-efficient secure routing and key management for mobile sinks in sensor networks, called SCODEplus. It is a significant extension of our previous study in five aspects: (1) Key management scheme and routing protocol are considered during design time to increase security and efficiency; (2) The network topology is organized in a hexagonal plane which supports more efficiency than previous square-grid topology; (3) The key management scheme can eliminate the impacts of node compromise attacks on links between non-compromised nodes; (4) Sensor node deployment is based on Gaussian distribution which is more realistic than uniform distribution; (5) No GPS or like is required to provide sensor node location information. Our security analysis demonstrates that the proposed scheme can defend against common attacks in sensor networks including node compromise attacks, replay attacks, selective forwarding attacks, sinkhole and wormhole, Sybil attacks, HELLO flood attacks. Both mathematical and simulation-based performance evaluation show that the SCODEplus significantly reduces the communication overhead, energy consumption, packet delivery latency while it always delivers more than 97 percent of packets successfully. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

Large Scale Environmental Monitoring through Integration of Sensor and Mesh Networks

by Raja Jurdak, Abdelhamid Nafaa and Alessio Barbirato

Sensors 2008, 8(11), 7493-7517; https://doi.org/10.3390/s8117493 - 24 Nov 2008

Cited by 21 | Viewed by 12911

Abstract

Monitoring outdoor environments through networks of wireless sensors has received interest for collecting physical and chemical samples at high spatial and temporal scales. A central challenge to environmental monitoring applications of sensor networks is the short communication range of the sensor nodes, which [...] Read more.

Monitoring outdoor environments through networks of wireless sensors has received interest for collecting physical and chemical samples at high spatial and temporal scales. A central challenge to environmental monitoring applications of sensor networks is the short communication range of the sensor nodes, which increases the complexity and cost of monitoring commodities that are located in geographically spread areas. To address this issue, we propose a new communication architecture that integrates sensor networks with medium range wireless mesh networks, and provides users with an advanced web portal for managing sensed information in an integrated manner. Our architecture adopts a holistic approach targeted at improving the user experience by optimizing the system performance for handling data that originates at the sensors, traverses the mesh network, and resides at the server for user consumption. This holistic approach enables users to set high level policies that can adapt the resolution of information collected at the sensors, set the preferred performance targets for their application, and run a wide range of queries and analysis on both real-time and historical data. All system components and processes will be described in this paper. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessArticle

A Mobile Sensor Network System for Monitoring of Unfriendly Environments

by Guangming Song, Yaoxin Zhou, Fei Ding and Aiguo Song

Sensors 2008, 8(11), 7259-7274; https://doi.org/10.3390/s8117259 - 14 Nov 2008

Cited by 48 | Viewed by 16908

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Review

Jump to: Editorial, Research, Other

267 KiB

Open AccessReview

Connectivity, Coverage and Placement in Wireless Sensor Networks

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

Sensors 2009, 9(10), 7664-7693; https://doi.org/10.3390/s91007664 - 28 Sep 2009

Cited by 146 | Viewed by 22525

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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Open AccessReview

An Overview on Wireless Sensor Networks Technology and Evolution

by Chiara Buratti, Andrea Conti, Davide Dardari and Roberto Verdone

Sensors 2009, 9(9), 6869-6896; https://doi.org/10.3390/s90906869 - 31 Aug 2009

Cited by 458 | Viewed by 40165

Abstract

Wireless sensor networks (WSNs) enable new applications and require non-conventional paradigms for protocol design due to several constraints. Owing to the requirement for low device complexity together with low energy consumption (i.e., long network lifetime), a proper balance between communication and signal/data processing [...] Read more.

Wireless sensor networks (WSNs) enable new applications and require non-conventional paradigms for protocol design due to several constraints. Owing to the requirement for low device complexity together with low energy consumption (i.e., long network lifetime), a proper balance between communication and signal/data processing capabilities must be found. This motivates a huge effort in research activities, standardization process, and industrial investments on this field since the last decade. This survey paper aims at reporting an overview of WSNs technologies, main applications and standards, features in WSNs design, and evolutions. In particular, some peculiar applications, such as those based on environmental monitoring, are discussed and design strategies highlighted; a case study based on a real implementation is also reported. Trends and possible evolutions are traced. Emphasis is given to the IEEE 802.15.4 technology, which enables many applications of WSNs. Some example of performance characteristics of 802.15.4-based networks are shown and discussed as a function of the size of the WSN and the data type to be exchanged among nodes. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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1578 KiB

Open AccessReview

Piezoelectric and Magnetoelectric Thick Films for Fabricating Power Sources in Wireless Sensor Nodes

by Shashank Priya, Jungho Ryu, Chee-Sung Park, Josiah Oliver, Jong-Jin Choi and Dong-Soo Park

Sensors 2009, 9(8), 6362-6384; https://doi.org/10.3390/s90806362 - 17 Aug 2009

Cited by 72 | Viewed by 19075

Abstract

In this manuscript, we review the progress made in the synthesis of thick film-based piezoelectric and magnetoelectric structures for harvesting energy from mechanical vibrations and magnetic field. Piezoelectric compositions in the system Pb(Zr,Ti)O₃–Pb(Zn_1/3Nb_2/3)O₃ (PZNT) have shown [...] Read more.

In this manuscript, we review the progress made in the synthesis of thick film-based piezoelectric and magnetoelectric structures for harvesting energy from mechanical vibrations and magnetic field. Piezoelectric compositions in the system Pb(Zr,Ti)O₃–Pb(Zn_1/3Nb_2/3)O₃ (PZNT) have shown promise for providing enhanced efficiency due to higher energy density and thus form the base of transducers designed for capturing the mechanical energy. Laminate structures of PZNT with magnetostrictive ferrite materials provide large magnitudes of magnetoelectric coupling and are being targeted to capture the stray magnetic field energy. We analyze the models used to predict the performance of the energy harvesters and present a full system description. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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192 KiB

Open AccessReview

Distributed Joint Source-Channel Coding in Wireless Sensor Networks

by Xuqi Zhu, Yu Liu and Lin Zhang

Sensors 2009, 9(6), 4901-4917; https://doi.org/10.3390/s90604901 - 22 Jun 2009

Cited by 18 | Viewed by 17472

Abstract

Considering the fact that sensors are energy-limited and the wireless channel conditions in wireless sensor networks, there is an urgent need for a low-complexity coding method with high compression ratio and noise-resisted features. This paper reviews the progress made in distributed joint source-channel [...] Read more.

Considering the fact that sensors are energy-limited and the wireless channel conditions in wireless sensor networks, there is an urgent need for a low-complexity coding method with high compression ratio and noise-resisted features. This paper reviews the progress made in distributed joint source-channel coding which can address this issue. The main existing deployments, from the theory to practice, of distributed joint source-channel coding over the independent channels, the multiple access channels and the broadcast channels are introduced, respectively. To this end, we also present a practical scheme for compressing multiple correlated sources over the independent channels. The simulation results demonstrate the desired efficiency. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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1091 KiB

Open AccessReview

Energy Options for Wireless Sensor Nodes

by Chris Knight, Joshua Davidson and Sam Behrens

Sensors 2008, 8(12), 8037-8066; https://doi.org/10.3390/s8128037 - 8 Dec 2008

Cited by 175 | Viewed by 22682

Abstract

Reduction in size and power consumption of consumer electronics has opened up many opportunities for low power wireless sensor networks. One of the major challenges is in supporting battery operated devices as the number of nodes in a network grows. The two main [...] Read more.

Reduction in size and power consumption of consumer electronics has opened up many opportunities for low power wireless sensor networks. One of the major challenges is in supporting battery operated devices as the number of nodes in a network grows. The two main alternatives are to utilize higher energy density sources of stored energy, or to generate power at the node from local forms of energy. This paper reviews the state-of-the art technology in the field of both energy storage and energy harvesting for sensor nodes. The options discussed for energy storage include batteries, capacitors, fuel cells, heat engines and betavoltaic systems. The field of energy harvesting is discussed with reference to photovoltaics, temperature gradients, fluid flow, pressure variations and vibration harvesting. Full article

(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)

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