International Journal of Distributed Sensor Networks http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Vehicular Delay Tolerant and Sensor Networks: Protocols and Applications Mon, 29 Jun 2015 11:19:58 +0000 http://www.hindawi.com/journals/ijdsn/2015/463539/ Dongkyun Kim, Juan C. Cano, Wei Wang, Floriano De Rango, and Kun Hua Copyright © 2015 Dongkyun Kim et al. All rights reserved. Mobile Sensing and Data Management for Sensor Networks 2014 Mon, 29 Jun 2015 10:54:28 +0000 http://www.hindawi.com/journals/ijdsn/2015/278146/ Jianwei Niu, Lei Shu, Zhangbing Zhou, and Yan Zhang Copyright © 2015 Jianwei Niu et al. All rights reserved. Fast Query-by-Singing/Humming System That Combines Linear Scaling and Quantized Dynamic Time Warping Algorithm Mon, 29 Jun 2015 09:24:35 +0000 http://www.hindawi.com/journals/ijdsn/2015/176091/ We newly propose a query-by-singing/humming (QbSH) system considering both the preclassification and multiple classifier-based method by combining linear scaling (LS) and quantized dynamic time warping (QDTW) algorithm in order to enhance both the matching accuracy and processing speed. This is appropriate for the QbSH of high speed in the huge distributed server environment. This research is novel in the following three ways. First, the processing speed of the QDTW is generally much slower than the LS method. So, we perform the QDTW matching only in case that the matching distance by LS algorithm is smaller than predetermined threshold, by which the entire processing time is reduced while the matching accuracy is maintained. Second, we use the different measurement method of matching distance in LS algorithm by considering the characteristics of reference database. Third, we combine the calculated distances of LS and QDTW algorithms based on score level fusion in order to enhance the matching accuracy. The experimental results with the 2009 MIR-QbSH corpus and the AFA MIDI 100 databases showed that the proposed method reduced the total searching time of reference data while obtaining the higher accuracy compared to the QDTW. Gi Pyo Nam and Kang Ryoung Park Copyright © 2015 Gi Pyo Nam and Kang Ryoung Park. All rights reserved. IUmote: A Framework for the Efficient Modelling, Evaluation, and Deployment of Algorithms and Hardware for Underwater Communications Sun, 28 Jun 2015 14:11:49 +0000 http://www.hindawi.com/journals/ijdsn/2015/358315/ We present an approach for the modelling and simulating of the modem section of underwater sensor networks. The proposal is based on a specially designed modem architecture and the use of simulation tools and models that represent each of the communication elements: the water medium, physical transducers, electronics, and coding/decoding software. The algorithms can be simulated in the modelling environment; this framework does not require recoding and allows the combination of real and modelled elements. In physical terms, the modem engine provides a decoupled pipelined design of the processing path for the algorithms which allows users to run complex algorithms without requiring a highly demanding specific hardware. The proposal includes a methodology that has allowed us to significantly reduce the effort required in the process, from algorithm development to the effective deployment of the system. As a case study, this paper shows its application and results in the evaluation of a multipath and Doppler-shift correction algorithms. Antonio Sanchez, Angel Perles, Pedro Yuste, Juan V. Capella, and Juan Jose Serrano Copyright © 2015 Antonio Sanchez et al. All rights reserved. Wireless Multimedia Sensor Network Based Subway Tunnel Crack Detection Method Sun, 28 Jun 2015 10:24:14 +0000 http://www.hindawi.com/journals/ijdsn/2015/184639/ Subway tunnel cracks directly reflect the structural integrity of a tunnel, and as such the detection of subway tunnel cracks is always an important task in tunnel structure monitoring. This paper presents a convenient, fast, and automated crack detection method based on a wireless multimedia sensor subway tunnel network. This method primarily provides a solution for image acquisition, image detection and identification of cracks. In order to quickly obtain a surface image of the tunnel, we used special train image sensor nodes to provide the high speed and high performance processing capability with a large-capacity battery. The proposed process can significantly reduce the amount of data transmission by compressing the binary image obtained by initial processing of the original image. We transferred the data compressed by the sensor to an appropriate station and uploaded them to a database when the train passes through the station. We also designed a fast, easy to implement fracture identification and detection image processing algorithm that can solve the image identification and detection problem. In real subway field tests, this method provided excellent performance for subway tunnel crack detection, and recognition. Bo Shen, Wen-Yu Zhang, Da-Peng Qi, and Xiao-Yang Wu Copyright © 2015 Bo Shen et al. All rights reserved. RPL Mobility Support for Point-to-Point Traffic Flows towards Mobile Nodes Sun, 28 Jun 2015 10:09:50 +0000 http://www.hindawi.com/journals/ijdsn/2015/470349/ The “routing protocol for low-power and lossy networks” (RPL) from the IETF ROLL working group is a widely used standard to support routing in wireless sensor networks (WSNs). Although the RPL protocol was originally designed with static topologies in mind, recently a number of extensions have been proposed to support traffic flows from mobile nodes towards a static gateway. However, this paper demonstrates that these solutions do not support traffic flows going the other direction, for example, from the gateway towards mobile devices. To remedy this, the paper first analyses the problems that prevent reliable traffic flows towards mobile devices when using RPL. Afterwards, a new mechanism to improve downward route updating is proposed. Our new approach minimizes the probability of connectivity loss by ensuring that the internal state of the static network remains consistent. Our solution is implemented and evaluated using both simulation tools and experimental facilities and it is shown that it improves the end-to-end packet delivery ratio to mobile nodes from 20–30% up to 80% while reducing the overall RPL signalling overhead without the use of location information. David Carels, Eli De Poorter, Ingrid Moerman, and Piet Demeester Copyright © 2015 David Carels et al. All rights reserved. A High Efficient and Real Time Data Aggregation Scheme for WSNs Sun, 28 Jun 2015 08:47:09 +0000 http://www.hindawi.com/journals/ijdsn/2015/261381/ Data aggregation is an important method of improving transmitting efficiency of WSNs, but existing researches have some disadvantages as follows: several periods delay will be generated when filtering messages; the reduplicated messages filtering ratio is low; complex calculations need to be executed; and extra hardware should be added to obtain high performance. To resolve these problems, this paper proposes a real time and high efficient data aggregation scheme (dynamical message list based data aggregation, DMLDA) based on clustering routing algorithm. DMLDA includes three procedures: activating nodes, clustering nodes, and filtering messages. In filtering procedure, a special data structure named dynamic list will be established in every filtering node; it is designed to store messages transmitted by filtering node, and, comparing current message with list’s items, the message’s redundancy can be judged without any delay. To improve the filtering efficiency, the message list can be adjusted dynamically. The three procedures of data aggregation are all introduced, and the filtering method is designed in detail in this paper. At last, a series of experiments are simulated to prove our scheme’s performance, and the advantages are analyzed in theory. Tao Du, Zhe Qu, Qingbei Guo, and Shouning Qu Copyright © 2015 Tao Du et al. All rights reserved. A Balance Privacy-Preserving Data Aggregation Model in Wireless Sensor Networks Sun, 28 Jun 2015 06:50:28 +0000 http://www.hindawi.com/journals/ijdsn/2015/937280/ Wireless sensor networks are always deployed in remote and hostile environments to gather sensitive information, in which sensor nodes are apt to encounter some serious leakage of sensitive data. Hence, privacy-preserving is becoming an increasingly important issue in security data aggregation for wireless sensor networks. In this paper, we propose a balance privacy-preserving data aggregation model (BPDA) based on slicing and mixing technology. Compared to fixed or random slicing, BPDA model gives a balance slicing mechanism to ensure that slice can be sent to the nodes which have lower privacy preservation and enhance the privacy-preserving efficacy. Furthermore, according to the influence of the node degree and energy, three different schemes are presented to keep the privacy-preserving data aggregation balance. Theoretical analysis and simulation show that BPDA model demonstrates a good performance in terms of privacy-preserving efficacy and communication overhead and prolongs the lifetime of network. Changlun Zhang, Chao Li, and Yi Zhao Copyright © 2015 Changlun Zhang et al. All rights reserved. An Optimized Approach for Time-Constrained and Reliable Bursty Data Acquisition in WMSNs Sun, 28 Jun 2015 06:28:37 +0000 http://www.hindawi.com/journals/ijdsn/2015/826937/ In real-time multimedia application that is used to monitor the safety of workers and working environment in industrial fields, a burst of multimedia data, such as still images and audio or video streams, generated by multimedia nodes equipped with cameras or microphones on demand, is required to be collected at a server within a specified time bound in a reliable manner. However, due to the limited resources in sensor devices, such as process capability, bandwidth, and energy, it is challengeable to satisfy the time constraints of various real-time multimedia applications. Therefore, we introduce an optimized approach in order to shorten the acquisition period of bursty traffic so that it can satisfy more applications with tighter time constraints. For this purpose, we devise a path reservation scheme for an energy-efficient and time-constrained data transmission and a frame-slot scheduling scheme using two channels that enables the concurrent data transmission. Simulation results show that our proposed approach reduces the bursty data acquisition time and enhances network throughput significantly compared to other ones. Phan Van Vinh and Hoon Oh Copyright © 2015 Phan Van Vinh and Hoon Oh. All rights reserved. A Novel Compression Technique for Multi-Camera Nodes through Directional Correlation Sun, 28 Jun 2015 06:28:35 +0000 http://www.hindawi.com/journals/ijdsn/2015/539838/ A major fraction of multimedia stream contents tends to be redundant and leads to wastage of storage capacity and channel bandwidth. In order to eliminate surplus data, standard video compression algorithms exploit spatial and temporal correlation present in video sequence. However, in case of a multisensor network, intersensor statistical redundancy is the most significant factor in acquiring efficient link utilization as well as making resultant findings valuable to the end user. In this paper, an extension to our previously proposed scheme has been presented to accomplish performance goals of a multisensor environment. Standard MPEG codec has been used to accomplish distributed motion compensation in prespecified directions known as directional correlation. Video frame correlation has been estimated locally at the camera node as well as across different nodes, defined as node communication strategies. Further, receiver feedback assists in quality control after reconstitution by decoder assessment. Results estimated have been analyzed for saving ratios and multimedia quality. Results analysis illustrates increased gains in frame quality and compression saving, achieved through reducing node displacement from the reference node . Saima Shaheen, M. Younus Javed, Muid Mufti, Shehzad Khalid, Aasia Khanum, Shoab A. Khan, and M. Usman Akram Copyright © 2015 Saima Shaheen et al. All rights reserved. Network Utilization Improvement via a Predictive Load Scheduling Scheme in Heterogeneous Wireless Networks Thu, 25 Jun 2015 10:43:30 +0000 http://www.hindawi.com/journals/ijdsn/2015/105769/ In heterogeneous wireless networks (HWNs), the large-coverage cellular networks are usually overlaid with denser small-coverage microcells, wireless local area networks (WLANs), femtocells, and even relays. To prevent unbalanced load distribution in these HWNs from decreasing network utilization and degrading the quality of service (QoS), load scheduling between the overlaid networks is essential and should be reasonably designed. In fact, unbalanced load distribution can be directly reflected by the idle durations of networks and channels. In this paper, a predictive load scheduling scheme is proposed from the point of decreasing the capacity-weighted idle durations of networks and channels. For the proposed scheme, a fairly general HWNs scenario is considered, the scheduling problem is formulated, an iteration-based predictive method is given to obtain the idle duration, and a gradient descent method is derived for the optimal scheduled load. In the simulation, the effectiveness of the idle duration prediction method is validated, and the simulation results show that the proposed load scheduling scheme can greatly improve the network utilization and QoS. Bin Fang and Wuyang Zhou Copyright © 2015 Bin Fang and Wuyang Zhou. All rights reserved. MIMO Radar Adaptive Waveform Design for Extended Target Recognition Thu, 25 Jun 2015 08:51:33 +0000 http://www.hindawi.com/journals/ijdsn/2015/154931/ The problems of multiple-input multiple-output (MIMO) radar adaptive waveform design in additive white Gaussian noise channels and multitarget recognition based on sequential likelihood ratio test are jointly addressed in this paper. Two information-theoretic waveform design strategies, namely, the optimal waveform for maximizing the mutual information (MI) between the extended target impulse response and the target echoes and the optimal waveform for maximizing the Kullback-Leibler (KL) divergence (or relative entropy), are applied in the multitarget recognition application. For multitarget case, two adaptive waveform design methods for all possible targets based on the current knowledge of each hypothesis are proposed. Method 1 is the probability weighted waveform method. Method 2 is the probability weighted target signature method. The optimal waveform is transmitted and adaptively changed such that a decision is made based on the likelihood ratio after several illuminations. Numerical results demonstrate that the best waveform is the KL divergence-based optimal waveform using Method 1 as it has the lowest average illumination number and the highest correct decision rate for target recognition. By optimally designing and adaptively changing the transmitted waveform, the average number of illuminations required for multitarget recognition can be much reduced. Lulu Wang, Kai-Kit Wong, Hongqiang Wang, and Yuliang Qin Copyright © 2015 Lulu Wang et al. All rights reserved. A Low-Complexity Approach for Improving the Accuracy of Sensor Networks Tue, 23 Jun 2015 10:54:17 +0000 http://www.hindawi.com/journals/ijdsn/2015/521948/ The paper addresses the problem of improving the accuracy of the measurements collected by a sensor network, where simplicity and cost-effectiveness are of utmost importance. An adaptive Bayesian approach is proposed to this aim, which allows improving the accuracy of the delivered estimates with no significant increase in computational complexity. Remarkably, the resulting cooperative algorithm does not require prior knowledge of the (hyper)parameters and is able to provide a “denoised” version of the monitored field without losing accuracy in detecting extreme (less frequent) values, which can be very important for a number of applications. A novel performance metric is also introduced to suitably quantify the capability to both reduce the measurement error and retain highly-informative characteristics at the same time. The performance assessment shows that the proposed approach is superior to a low-complexity competitor that implements a conventional filtering approach. Angelo Coluccia Copyright © 2015 Angelo Coluccia. All rights reserved. Maximizing Throughput with Wireless Spectrum Sensing Network Assisted Cognitive Radios Mon, 22 Jun 2015 12:22:31 +0000 http://www.hindawi.com/journals/ijdsn/2015/195794/ In a cognitive radio network (CRN), secondary users (SUs) utilize primary users (PUs) licensed spectrum in an opportunistic manner. Spectrum sensing is of the utmost importance in CRN to find and use the available spectrum without harmful interference to the PUs. Conventionally, to implement spectrum utilization, SUs are required to sense the primary spectrum first and then transmit data on the available spectrum. In this paper, we propose a dedicated wireless spectrum sensing network (WSSN), eliminating sensing overhead from SUs with the aim of improving achievable throughput. With WSSN assistance, we eliminate sensing time from the SUs frame, hence increasing the transmission time, which maximizes the achievable throughput. Additionally, the sensing duration is increased by deploying a dedicated WSSN, decreasing the probability of false alarm and achieving a targeted high probability of detection. A low probability of false alarm increases the spectrum utilization, improving the achievable throughput, while a high detection probability ensures PUs protection. Moreover, the proposed technique also addresses hidden and exposed terminal problems along with smooth spectrum mobility. Finally, we provide simulation results to demonstrate the proposed techniques, effectiveness. In the results, we have compared the achievable throughput of the proposed scheme with that of conventional CRN. Arbab Waheed Ahmad, Heekwon Yang, and Chankil Lee Copyright © 2015 Arbab Waheed Ahmad et al. All rights reserved. Design and Implementation of Spatial Operators and Energy-Efficient Query Processing Strategy in Wireless Sensor Network Database System Mon, 22 Jun 2015 06:14:15 +0000 http://www.hindawi.com/journals/ijdsn/2015/509471/ Database applications in wireless sensor networks very often demand data collection from sensor nodes of specific target regions. Design and development of spatial query expressions and energy-efficient query processing strategy are important issues for sensor network database systems. The existing sensor network database systems lack the needed sophistication for the space calculation of the target sensor nodes; hence, unnecessary query/data transmissions are required between the sensor nodes and the server. This paper describes our spatial operations and energy-efficient query processing methods that are designed and implemented in our sensor network database system called . With a set of spatial operators based on geometric parameters, such as Envelope, NearBy, Distance, Direction, and set theoretic operators, allows sensor network applications to easily specify the target space of interest. Our energy-efficient query processing strategy implements an in-network query management based on the lowest common ancestor (LCA) algorithm, so that the query processing cost for calculating the target spaces is greatly reduced by avoiding the need of heavy query/data transmissions between the base-station and target nodes. Performance evaluation shows that our proposed design and implementation of spatial query expressions and processing strategy achieve improved energy efficiency for database operations in the wireless sensor network. Chong sok Lim, Jeong-Hoon Lee, Minjee Park, and Soon J. Hyun Copyright © 2015 Chong sok Lim et al. All rights reserved. Wireless Sensor Networks for Agriculture and Forestry Mon, 22 Jun 2015 05:53:44 +0000 http://www.hindawi.com/journals/ijdsn/2015/845364/ Guomo Zhou, Shaojie Tang, Dengsheng Lu, Liang Liu, Jinsong Han, and Wei Dong Copyright © 2015 Guomo Zhou et al. All rights reserved. On Dynamic Video Source Decision in VANETs: An On-Demand Clustering Approach Sun, 21 Jun 2015 12:18:26 +0000 http://www.hindawi.com/journals/ijdsn/2015/436810/ In vehicular ad hoc networks (VANETs), video communication makes a significant contribution to quality of experience (QoE) for people on the road. However, the selection of the video source is an impediment to video delivery due to the high mobility and dynamic topology of VANETs. An improper provider not only leads to frequent interruptions of communications, but the transmission of the invalid video fragments would also result in the waster of precious bandwidth. To address the issue, a novel video source decision scheme, named Cluster and Dynamic Overlay based video delivery over VANETs (CDOV), is proposed in this paper. By the on-demand clustering approach, nodes with the same video requirement/supply and moving features are clustered. Further, in a cluster, an overlay tree is constructed dynamically based on the relation between supply and demand, in which all requesters can find their greedy optimal source easily. In addition, the intracluster communication and head-RSU communication are designed for video streaming over this network structure. Using extensive simulations, the effectiveness of the proposed scheme is demonstrated. Compared with two existing works, the proposed solution is capable of obtaining lower startup latency and higher delivery ratio. Lina Zhu, Changle Li, Yun Chen, and Bingbing Li Copyright © 2015 Lina Zhu et al. All rights reserved. Network Coding versus Replication Based Resilient Techniques to Mitigate Insider Attacks for Smart Metering Sun, 21 Jun 2015 11:43:02 +0000 http://www.hindawi.com/journals/ijdsn/2015/737269/ The main focus of this paper is the resilience of communication protocols for data gathering in distributed, large scale, and dense networks. In our previous work, we have proposed the resilient methods based on random behavior and data replications to improve route diversification, thus to take advantage of redundant network structure. Following these previous methods, we propose in this paper a new resilient method based on network coding techniques to improve resilience in Wireless Sensor Networks (WSNs) for smart metering applications. More precisely, using our resilience metric based on a performance surface, we compare several variants of a well-known gradient based routing protocol with the previous methods (random routing and packet replications) and the new proposed methods (two network coding techniques). The proposed methods outperformed the previous methods in terms of data delivery success even in the presence of high attack intensity. Pierre Brunisholz, Ochirkhand Erdene-Ochir, Mohamed Abdallah, Khalid Qaraqe, Marine Minier, and Fabrice Valois Copyright © 2015 Pierre Brunisholz et al. All rights reserved. Resource Allocation Algorithm Based on Profit Maximization for Crowd Sensing Thu, 18 Jun 2015 11:28:37 +0000 http://www.hindawi.com/journals/ijdsn/2015/264125/ The key to realizing the crowd sensing network is to overcome the resource restrictions of energy, bandwidth, computing, and so on. First of all, due to the number of users and sensor availability will be dynamic change over time, crowd sensing system is difficult to accurately predict and allocate resource to accomplish a specific task. Secondly, there is a need to consider how to choose an effective subset from a large number of users with different sensing ability, so as to allocate the sensing devices in communication resources under the constraint conditions. This paper proposes a profit maximization algorithm for resource allocation component in crowd sensing environment. The proposed algorithm not only considers the current profit of crowd sensing service request but also considers the long-term expected profits, so as to ensure long-term maximum profit. The objective function is no longer to minimize the completion time but rather to achieve the target profit maximization. The experimental results show that the new algorithm is feasible and superior to the traditional algorithms. Kun Gao, Bin Wang, and Xinwu Yu Copyright © 2015 Kun Gao et al. All rights reserved. A Fault Diagnosis Scheme for Aircraft Multibranches Wiring Network Based on Matching Algorithm Thu, 18 Jun 2015 11:19:12 +0000 http://www.hindawi.com/journals/ijdsn/2015/158364/ This paper mainly describes a fault diagnosis scheme for aircraft multibranches wiring networks. The background theory is based on the matching algorithm with theoretical reflection waveform and realistic reflection waveform. Firstly, a numerical model with a comprehensive database was built to create the theoretical waveform of the measured wiring network. On the other hand, the realistic reflection waveform of the measured wiring network can be collected by reflectometry detection system. Then, the waveform matching algorithm and fault diagnosis algorithm were applied to detect the fault type and fault location in the measured wiring network. With all the steps above, the fault diagnosis scheme was designed and realized. Finally, a multibranches wiring network, which includes two branches, and one of its branches contains two subbranches with different types of faults, was built to verify the fault diagnosis scheme and the results show that the scheme is an effective way to diagnose faults in multibranches wiring network. Wang Liwen, Zhang Lu, Xu Meng, and Shi Xudong Copyright © 2015 Wang Liwen et al. All rights reserved. Development of a Multisensor Embedded Intelligent Home Environment Monitoring System Based on Digital Signal Processor and Wi-Fi Thu, 18 Jun 2015 11:17:33 +0000 http://www.hindawi.com/journals/ijdsn/2015/171365/ Wi-Fi has been widely adopted by families in Taiwan, for it has the advantage of designing family monitoring systems with its wide usage. Therefore, there are many advantages for designing family monitoring systems. Based on our previous research architecture, we implemented a monitoring system for family environments based on Wi-Fi and sensor technologies. Humidity, gas, smoke, and temperature sensors are applied for designing and developing the intelligent home environment monitoring system in this paper. A system prototype is proposed in this research, and the experimental results are discussed. The results showed that the system is workable and remarkable for environment monitoring. The contribution of this is to propose a framework for future home environment monitoring system developers to refer to. Shang-Liang Chen, Shu-Kai Chang, and Yun-Yao Chen Copyright © 2015 Shang-Liang Chen et al. All rights reserved. A Community Finding Method for Weighted Dynamic Online Social Network Based on User Behavior Thu, 18 Jun 2015 11:12:32 +0000 http://www.hindawi.com/journals/ijdsn/2015/306160/ Revealing the structural features of social networks is vitally important to both scientific research and practice, and the explosive growth of online social networks in recent years has brought us dramatic advances to understand social structures. Here we proposed a community detection approach based on user interaction behavior in weighted dynamic online social networks. We researched interaction behaviors in online social networks and built a directed and unweighted network model in terms of the Weibo following relationships between social individuals at the very beginning. In order to refine the interaction behavior, level one fuzzy comprehensive evaluation model was employed to describe how closely individuals are connected to each other. According to this intimate degree description, weights are tagged to the prior unweighted model we built. Secondly, a heuristic community detection algorithm for dynamic network was provided based on the improved version of modularity called module density. As for the heuristic rule, we chose greedy strategy and merely fed the algorithms with the changed parts within neighboring time slice. Experimental results show that the proposed algorithm can obtain high accuracy and simultaneously get comparatively lower time complexity than some typical algorithms. More importantly, our algorithm needs no a priori conditions. Dongming Chen, Yanlin Dong, Xinyu Huang, Haiyan Chen, and Dongqi Wang Copyright © 2015 Dongming Chen et al. All rights reserved. Comparison of Ontological Subscription and Blocking and Rich Site Summary for Blog Posts Thu, 18 Jun 2015 09:42:02 +0000 http://www.hindawi.com/journals/ijdsn/2015/418102/ Information overload and privacy protection become critical issues with blogs. This paper presents the ontological subscription and blocking system (OSBS) using policies, ontologies, and rules to subscribe interesting posts and block unwanted posts. This system also uses rules for automatic conflict detection between polices. The effectiveness of two subscription systems, OSBS and RSS (rich site summary) reader, is compared. The experimental results reveal that the perceived privacy benefits on the novel OSBS are better than the existing RSS reader. The novel OSBS is as good as existing RSS reader from perceived information overload alleviation perspective. Chi-Lun Liu Copyright © 2015 Chi-Lun Liu. All rights reserved. Minimizing the Number of Mobile Chargers to Keep Large-Scale WRSNs Working Perpetually Thu, 18 Jun 2015 08:38:52 +0000 http://www.hindawi.com/journals/ijdsn/2015/782952/ Wireless Rechargeable Sensor Networks, in which mobile chargers (s) are employed to recharge the sensor nodes, have attracted wide attention in recent years. Under proper charging schedules, the s could keep all the sensor nodes working perpetually. Since s can be very expensive, this paper tackles the problem of deciding the minimum number of s and their charging schedules to keep every sensor node working continuously. This problem is NP-hard; we divide it into two subproblems and propose a GCHA (Greedily Construct, Heuristically Assign) scheme to solve them. First, the GCHA greedily addresses a Tour Construction Problem to construct a set of tours to 1-cover the WRSN. Energy of the sensor nodes in each of these tours can be timely replenished by one according to the decision condition derived from a Greedy Charging Scheme (GCS). Second, the GCHA heuristically solves a Tour Assignment Problem to assign these tours to minimum number of s. Then each of the s can apply the GCS to charge along its assigned tours. Simulation results show that, on average, the number of s obtained by the GCHA scheme is less than 1.1 over a derived lower bound and less than 0.5 over related work. Cheng Hu and Yun Wang Copyright © 2015 Cheng Hu and Yun Wang. All rights reserved. Advances in Multimedia Sensor Networks for Health-Care and Related Applications Thu, 18 Jun 2015 08:27:45 +0000 http://www.hindawi.com/journals/ijdsn/2015/596096/ M. Shamim Hossain, Al-Sakib Khan Pathan, Stefan Goebel, Shawon M. Rahman, and Manzur Murshed Copyright © 2015 M. Shamim Hossain et al. All rights reserved. Neuromorphic Sensor Network Platform: A Bioinspired Tool to Grow Applications in Wireless Sensor Networks Wed, 17 Jun 2015 14:09:33 +0000 http://www.hindawi.com/journals/ijdsn/2015/230401/ Wireless Sensor Networks (WSNs) must face the challenge of producing a vast plethora of applications from the least possible number of distributed sensors. In this paper we describe the Neuromorphic Sensor Network (NSN) platform, which implements a bioinspired approach to the development of growing applications in WSNs. NSNs follow an analogy with the neurophysiology of vertebrates, compressing the information coming from sets of sensors in wireless nodes and processing it by means of a set of processing units (PUs) that perform individual general purpose functions. Applications are then constructed through specific connections of these PUs, generating application pathways that allow the reuse of the same distributed NSN to give response to any desired output, thus achieving an application scalability. We illustrate the detailed process of growing applications using the NSN platform through an object tracking tool that mimics the behavior of the vertebrates visual system to detect and track objects. Finally, we describe a real implementation of the NSN platform in a road traffic monitoring and information system currently in operation in the cities of Madrid and Seville (Spain). Mark Richard Wilby, Ana Belén Rodríguez González, Juan José Vinagre Díaz, and Jesús Requena Carrión Copyright © 2015 Mark Richard Wilby et al. All rights reserved. A Novel Energy-Efficient Clustering Based Cooperative Spectrum Sensing for Cognitive Radio Sensor Networks Wed, 17 Jun 2015 08:16:42 +0000 http://www.hindawi.com/journals/ijdsn/2015/198456/ Cognitive radio has been proposed as a promising way to effectively utilize the scarce spectrum resources. A cognitive radio sensor network (CRSN) is a wireless sensor network that is equipped with cognitive radio capability. Clustering is a popular technique that can be applied to wireless sensor networks, although it has been proven to be a challenge to implement it in CRSNs. Moreover, few proposals have successfully applied energy-efficient clustering techniques in CRSNs. Therefore, with the aim of increasing energy efficiency, network lifetime, network stability, and optimal cluster-head selection process, this paper proposes a novel energy-efficient clustering based on cooperative spectrum sensing (ECS) for CRSNs. The proposed ECS scheme utilizes the concept of pairing among sensor nodes and switches between Awake and Sleep modes for energy efficiency. A comprehensive simulation in MATLAB was carried out to validate the proposed method. The simulation results show that, compared with conventional methods, the proposed method is more energy efficient and that the overall CRSN’s lifetime is prolonged. Ashish Rauniyar and Soo Young Shin Copyright © 2015 Ashish Rauniyar and Soo Young Shin. All rights reserved. Convergence Rate Estimate of Distributed Localization Algorithms in Wireless Sensor Networks Tue, 16 Jun 2015 12:16:03 +0000 http://www.hindawi.com/journals/ijdsn/2015/523285/ Localization is one of the most important problems in wireless sensor networks. In this paper, we investigate the convergence rate estimate problem of a distributed localization algorithm which approximately formulates the localization problem as the convex feasibility problem including the consistent case and the inconsistent case. Although existing works established optimal consensus convergence analysis for this algorithm, they did not provide the convergence rate estimate. In this paper, we mainly show that for the consistent case the convergence rate of the optimal consensus will be exponential under some basic conditions, while for the inconsistent case we provide a necessary condition for the optimal consensus and a convergence rate estimate inequality. Furthermore, numerical examples are also provided to validate the established convergence and convergence rate results. Shujuan Pang Copyright © 2015 Shujuan Pang. All rights reserved. Fuzzy System of Irrigation Applied to the Growth of Habanero Pepper (Capsicum chinense Jacq.) under Protected Conditions in Yucatan, Mexico Tue, 16 Jun 2015 08:07:09 +0000 http://www.hindawi.com/journals/ijdsn/2015/123543/ Agriculture is the largest user of water worldwide by using about 70 percent of total consumption. The world food production depends on the availability of water, considering factors such as demographic and climate change, so the use of efficient irrigation is necessary to apply the correct amount of water to crops. The traditional irrigation systems generally program their scheme based on measurements made at Class A evaporimeter pan. In this paper an irrigation scheme defined by an algorithm that automates the amount of water supplied is presented, it considers the consumption of habanero pepper crop, and a fuzzy system evaluates the necessary duration of irrigation. The climatic variables considered are temperature, relative humidity, and soil moisture. The algorithm was programmed in a microcontroller Atmel 328p included in Arduino platform, with the addition of a ZigBee wireless system that allows for monitoring through a PC. The climatic variables were inserted into the fuzzy system by sets of trapezoidal and triangular form and a Mamdani type inference mechanism in which the knowledge of an expert is registered through the fuzzy rules. The system was applied to a habanero pepper crop at Conkal Institute of Technology in Yucatan, Mexico. Martha Rocio Ceballos, Juan Luis Gorricho, Oscar Palma Gamboa, Mónica Karel Huerta, David Rivas, and Mayra Erazo Rodas Copyright © 2015 Martha Rocio Ceballos et al. All rights reserved. Analysis and Solutions to 3G Gateway Issues in Agriculture WSNs Tue, 16 Jun 2015 07:56:57 +0000 http://www.hindawi.com/journals/ijdsn/2015/306801/ Wireless sensor networks (WSN) are used extensively in various important areas of agriculture. Many of the associated activities involve the transmission of data or control commands through gateways that connect the servers to 3G networks. In this paper, we investigate the issues caused by Radio Resource Control (RRC) state transitions, which introduce high sudden delays in TCP packets. The packets that are subjected to these delays are then usually retransmitted because of timeouts. Further, the recently recommended TCP retransmission timer settings (RFC6298) reduce the initial retransmission timeout (RTO) from the previous three seconds to one second, further exacerbating the phenomenon of SYN packet retransmission, because a SYN packet is always the first packet to trigger the RRC state to change. We conduct a number of tests to examine the phenomenon and analyze the effect of this spurious retransmission timeout. Consequently, we propose recommendations for improvement. Zhihui Ge, Wei Liu, Tao Shen Li, and Jin Ye Copyright © 2015 Zhihui Ge et al. All rights reserved.