International Journal of Distributed Sensor Networks http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. RCIA: A New Ultralightweight RFID Authentication Protocol Using Recursive Hash Mon, 26 Jan 2015 11:52:56 +0000 http://www.hindawi.com/journals/ijdsn/2015/642180/ RFID is one of the most protuberant systems in the field of ubiquitous computing. Since RFID tags have limited computation capabilities, numerous ultralightweight authentication protocols have been proposed to provide privacy and security. However all the previously proposed ultralightweight mutual authentication protocols have some security apprehensions and are vulnerable to various desynchronization and full disclosure attacks. This paper proposes a new ultralightweight mutual authentication protocol to provide robust confidentiality, integrity, and authentication (RCIA) in a cost effective manner. RCIA introduces a new ultralightweight primitive recursive hash, which efficiently detects the message tempering and also avoids all possible desynchronization attacks. RCIA involves only bitwise operations such as XOR, AND, left rotation, and recursive hash. Performance evaluation illustrates that RCIA requires less resources on tag in terms of on-chip memory, communication cost, and computational operations. Umar Mujahid, M. Najam-ul-Islam, and M. Ali Shami Copyright © 2015 Umar Mujahid et al. All rights reserved. Optimum Power Distance Clustering for the EPC Class-1 Gen2 Standard in RFID Systems Thu, 22 Jan 2015 14:16:42 +0000 http://www.hindawi.com/journals/ijdsn/2015/154064/ Tag collision is one of the main issues impacting the performance of radio-frequency identification (RFID) systems. Several research efforts have been done in order to solve such problem. Current RFID standards, such as EPCGen2 and ISO-18000-7, adopt ALOHA-based protocols as the basis to solve collisions. In recent years, there has been a trend on designing schemes that split the interrogation zone into smaller regions with the aim of improving the system’s performance. In this paper, we evaluate and optimize the performance of ALOHA-based protocols for this new type of partitioning schemes. We establish the guidelines for adapting ALOHA protocols to this new approach in order to exploit the advantages it offers. Thus, we propose a new version of the EPCGen2 standard adapted to the new partitioning schemes, which overcomes its counterpart for the traditional approach, significantly reducing the identification delay, which is the main parameter to optimize in RFID. Leonardo Sanchez and Victor Ramos Copyright © 2015 Leonardo Sanchez and Victor Ramos. All rights reserved. Gossiping with Message Splitting on Structured Networks Thu, 22 Jan 2015 13:47:24 +0000 http://www.hindawi.com/journals/ijdsn/2015/504581/ Gossiping of a single source with multiple messages (by splitting information into pieces) has been treated only for complete graphs, shown to considerably reduce the completion time, that is, the first time at which all network nodes are informed, compared with single-message gossiping. In this paper, gossiping of a single source with multiple messages is treated, for networks modeled as certain structured graphs, wherein upper bounds of the high-probability completion time are established through a novel “dependency graph” technique. The results shed useful insights into the behavior of multiple-message gossiping and can be useful for data dissemination in sensor networks, multihopping content distribution, and file downloading in peer-to-peer networks. Wenxiang Dong, Ying Yang, and Wenyi Zhang Copyright © 2015 Wenxiang Dong et al. All rights reserved. A Topology Control Algorithm for Sensor Networks Based on Robust Optimization Wed, 21 Jan 2015 07:12:51 +0000 http://www.hindawi.com/journals/ijdsn/2015/140709/ In recent years, wireless sensor networks have been widely used in data acquisition, surveillance, event monitoring, and so forth. Topology control is an important issue in designing sensor networks. Considering the uncertainty of distance between nodes, a distributed topology control algorithm named as LRMST, which is based on the local minimum spanning tree (LMST) algorithm, is proposed by applying the 0-1 robust discrete optimization theory. Firstly, when only the cost coefficients are subject to uncertainty, it is proved that the robust counterpart of the 0-1 discrete optimization problem on variables can be solved by solving at most deterministic problems, where denotes the number of cost coefficients which change in an uncertainty set. Then we present a robust model for the MST problem under distance uncertainty. According to the proved conclusion, an algorithm is proposed to obtain the robust solution of uncertain MST problem by solving only one deterministic MST problem, after which LRMST algorithm is designed when the distance between nodes is affected by uncertainty. Simulation results show that LRMST algorithm tends to select some edges whose estimated distance is slightly longer and obtains the robustness when the distance is uncertain at the expense of less optimal value compared with LMST algorithm. Junfeng Qiao, Sanyang Liu, and Wei Duan Copyright © 2015 Junfeng Qiao et al. All rights reserved. Improving Wi-Fi Indoor Positioning via AP Sets Similarity and Semi-Supervised Affinity Propagation Clustering Tue, 20 Jan 2015 08:14:47 +0000 http://www.hindawi.com/journals/ijdsn/2015/109642/ Indoor localization techniques using Wi-Fi fingerprints have become prevalent in recent years because of their cost-effectiveness and high accuracy. The most common algorithm adopted for Wi-Fi fingerprinting is weighted K-nearest neighbors (WKNN), which calculates K-nearest neighboring points to a mobile user. However, existing WKNN cannot effectively address the problems that there is a difference in observed AP sets during offline and online stages and also not all the K neighbors are physically close to the user. In this paper, similarity coefficient is used to measure the similarity of AP sets, which is then combined with radio signal strength values to calculate the fingerprint distance. In addition, isolated points are identified and removed before clustering based on semi-supervised affinity propagation. Real-world experiments are conducted on a university campus and results show the proposed approach does outperform existing approaches. Xuke Hu, Jianga Shang, Fuqiang Gu, and Qi Han Copyright © 2015 Xuke Hu et al. All rights reserved. An Energy and Latency Aware WSN MAC Protocol for Bidirectional Traffic in Data Collection Sun, 18 Jan 2015 10:48:27 +0000 http://www.hindawi.com/journals/ijdsn/2015/907538/ This paper proposes a new Energy and Latency Aware MAC (ELA-MAC) protocol that provides high energy-efficiency and low latency for data collection applications in wireless sensor networks. In previous research, B-MAC+ avoids the receiver node’s preamble overhearing of B-MAC with short preamble packets including only the destination address and the preamble packet number. However, like B-MAC, B-MAC+ has the sender node’s preamble overhead and communication latency. XY-MAC tries to solve these problems with inserting an early ACK between preamble packets. However, with the independence of each node’s wake-up point, the receiver node’s idle listening duration of XY-MAC is always longer than that of B-MAC+. ELA-MAC spreads collection-request without using an early ACK and delivers collection-response using an early ACK with considering the traffic types such as broadcasting and convergecasting. In this way, energy consumption on both downlink and uplink can be reduced. Besides, the time for collecting data can be shortened on uplink. With the experimental parameter obtained by the energy consumption analysis, the experiment was performed on a real sensor network test bed with various topologies. We obtained the result that ELA-MAC improves the energy efficiency by 12% and 37% compared to B-MAC+ and XY-MAC, respectively, and data collection time by 28% compared to B-MAC+. Ji-Yeon Min, Sang-Hwa Chung, and Yuvin Ha Copyright © 2015 Ji-Yeon Min et al. All rights reserved. A Wireless Pressure Microsensor Fabricated in HTCC Technology for Dynamic Pressure Monitoring in Harsh Environments Wed, 14 Jan 2015 06:23:10 +0000 http://www.hindawi.com/journals/ijdsn/2015/974742/ The partially stabilized zirconia (PSZ) ceramic has wide applications due to its excellent mechanical toughness and chemically inert and electrical properties for fabricating various devices. In this paper, a novel high temperature pressure sensor with the PSZ was designed and fabricated. The sensor was designed based on the small deflection theory, which enables its theoretic pressure-capacitance capability up to 60 bar. HTCC process technology was used to fabricate the sensor, which would realize a completely passive LC resonant circuit integrated on the ceramic substrate. According to the coupling principle, noncontact testing is achieved using the designed readout system, with average sensitivity up to 38 kHz Bar−1 presented. Compared to the fabrication and measurement of traditional sensors, excellent packaging process is demonstrated, and the sensor can be completely tested from 0 to 60 bar. Ronghui Gao, Yingping Hong, Huixin Zhang, Wenyi Liu, Ting Liang, Wendong Zhang, and Jijun Xiong Copyright © 2015 Ronghui Gao et al. All rights reserved. A Three-Phase Top- Query Based Distributed Data Collection Scheme in Wireless Sensor Networks Sun, 11 Jan 2015 07:01:10 +0000 http://www.hindawi.com/journals/ijdsn/2015/856507/ We propose a three-phase top- query based distributed data collection scheme which is designed for clustered or multisink wireless sensor networks. The proposed scheme consists of a distributed iterative hard thresholding algorithm and a three-phase top- query algorithm. In the distributed iterative hard thresholding algorithm, the cluster heads or sink nodes reconstruct the compressed data in a distributed and cooperative manner. Meanwhile, the top- query operation in the above algorithm is realized by pruning unnecessary elements among cluster heads or sink nodes in the three-phase top- query algorithm. Simulation results show that there is no obvious difference in the performance of data reconstruction between our proposed scheme and existing compressive sensing theory based data collection schemes. However, both the number of interactions and the amount of transmitted data among cluster heads or sink nodes can be effectively reduced in the proposed scheme. The performance of the proposed scheme is analyzed in detail in this paper to support the claims. Guorui Li, Jingsha He, and Cong Wang Copyright © 2015 Guorui Li et al. All rights reserved. Sensor-Assisted Face Tracking Thu, 08 Jan 2015 07:59:16 +0000 http://www.hindawi.com/journals/ijdsn/2015/173535/ Generally, face detection and tracking focus only on visual data analysis. In this paper, we propose a novel method for face tracking in camera video. By making use of the context metadata captured by wearable sensors on human bodies at the time of video recording, we could improve the performance and efficiency of traditional face tracking algorithms. Specifically, when subjects wearing motion sensors move around in the field of view (FOV) of a camera, motion features collected by those sensors help to locate frames most probably containing faces from the recorded video and thus save large amount of time spent on filtering out faceless frames and cut down the proportion of false alarms. We conduct extensive experiments to evaluate the proposed method and achieve promising results. Dingbo Duan and Jian Ma Copyright © 2015 Dingbo Duan and Jian Ma. All rights reserved. An Efficiency Multiplexing Scheme and Improved Sampling Method for Multichannel Data Acquisition System Tue, 06 Jan 2015 07:25:39 +0000 http://www.hindawi.com/journals/ijdsn/2015/626307/ The paper proposes an efficient multiplexing scheme that is easy to realize synchronous sampling in a multichannel acquisition system with the large number of analogue inputs and different sampling rates. And then, a simple improved sampling control method is also employed to improve the performance. All the technology of implementing the method is by using a low-cost field programmable gate array (FPGA). A sampling lookup table is built by the rule-based synchronous sampling frame structure for the input analogue multiplexers and stored into the internal block RAM resource in the FPGA to reduce the internal wiring resources and optimize the utilization. The improved sampling method obtains several samples in a sampling period and gets the average value as the final output for the sampling channel. In addition, the standard sine wave FFT test method is implemented to test the dynamic parameters of the acquisition channels. The experiment results show that the dynamic performance of the acquisition system is significantly improved. The proposed multiplexing scheme and sampling method can easily be reconfigured for other applications. Chengqun Chu, Yongfeng Ren, Xin Liu, Yongqiu Zheng, and Wei Fang Copyright © 2015 Chengqun Chu et al. All rights reserved. A Handshake Based Ordered Scheduling MAC Protocol for Underwater Acoustic Local Area Networks Thu, 01 Jan 2015 14:17:56 +0000 http://www.hindawi.com/journals/ijdsn/2015/984370/ Underwater acoustic local area networks (UA-LANs) can be used to improve the coverage of an underwater network by introducing a tier of local area communications. Media access control (MAC) is a crucial issue for UA-LANs. Existing MAC protocols for terrestrial WLANs cannot be directly applied to UA-LANs due to the acoustic channel features of limited bandwidth and high and variable propagation delay. In this paper, we propose a handshake based ordered scheduling MAC (HOSM) protocol for UA-LANs. The nodes with data packets to be transmitted first reserve the channel in a channel reservation phase. Then an order list is calculated, and the data packets of these nodes are transmitted according to this order list. We develop a control packets transmission adjustment mechanism to reduce collisions of control packets. The key idea of this mechanism is to utilize the information of propagation delay to adjust the time instant of control packets transmitting. To improve channel utilization, we present a variant Max-Min Ant System algorithm to calculate an optimal order for each data transmission round. Simulation results have confirmed that the proposed protocol can achieve high throughput with low delay and good spatial fairness. Zilong Liao, Deshi Li, and Jian Chen Copyright © 2015 Zilong Liao et al. All rights reserved. Heterogeneous Resource Allocation Algorithm for Ad Hoc Networks with Utility Fairness Thu, 01 Jan 2015 11:52:04 +0000 http://www.hindawi.com/journals/ijdsn/2015/686189/ Resource allocation is expected to be a most important factor especially for heterogeneous applications in wireless ad hoc networks. In this paper, a novel heterogeneous resource allocation algorithm (HRA) is presented for ad hoc networks, supporting both elastic and inelastic traffic. First, by combining the first order Lagrangian method with pseudo utility, the original nonconvex problem is converted into a new convex one. Then, we successfully solve the heterogeneous problem with the dual-based decomposition approach. In addition, we integrate utility fairness into the resource allocation framework, which can adaptively manage the tradeoff between elastic and inelastic flows. Simulations show and prove that HRA converges fast and can achieve the global optimum starting from many different network conditions, such as elastic, inelastic, and hybrid scenario. With both considerations of flow rate and utility fairness, HRA improves the overall network utility and system throughput greatly. Bing-Qing Han, Guo-Fu Feng, and Yi-Fei Chen Copyright © 2015 Bing-Qing Han et al. All rights reserved. Recent Trends in Wireless Sensor Networks with Applications Wed, 31 Dec 2014 12:58:05 +0000 http://www.hindawi.com/journals/ijdsn/2014/912574/ Mohamed A. Tawhid and Hasan Mahmood Copyright © 2014 Mohamed A. Tawhid and Hasan Mahmood. All rights reserved. Sensing, Perceiving, and Understanding Actions Wed, 31 Dec 2014 08:56:19 +0000 http://www.hindawi.com/journals/ijdsn/2014/790210/ Juan Carlos López, María José Santofimia, Jesús Martínez del Rincón, and Scott E. Fahlman Copyright © 2014 Juan Carlos López et al. All rights reserved. Fortifying Intrusion Detection Systems in Dynamic Ad Hoc and Wireless Sensor Networks Mon, 29 Dec 2014 09:48:13 +0000 http://www.hindawi.com/journals/ijdsn/2014/608162/ We investigate three aspects of dynamicity in ad hoc and wireless sensor networks and their impact on the efficiency of intrusion detection systems (IDSs). The first aspect is magnitude dynamicity, in which the IDS has to efficiently determine whether the changes occurring in the network are due to malicious behaviors or or due to normal changing of user requirements. The second aspect is nature dynamicity that occurs when a malicious node is continuously switching its behavior between normal and anomalous to cause maximum network disruption without being detected by the IDS. The third aspect, named spatiotemporal dynamicity, happens when a malicious node moves out of the IDS range before the latter can make an observation about its behavior. The first aspect is solved by defining a normal profile based on the invariants derived from the normal node behavior. The second aspect is handled by proposing an adaptive reputation fading strategy that allows fast redemption and fast capture of malicious node. The third aspect is solved by estimating the link duration between two nodes in dynamic network topology, which allows choosing the appropriate monitoring period. We provide analytical studies and simulation experiments to demonstrate the efficiency of the proposed solutions. Abdelouahid Derhab, Abdelghani Bouras, Mustapha Reda Senouci, and Muhammad Imran Copyright © 2014 Abdelouahid Derhab et al. All rights reserved. Link Layer Time-Varying Model for IEEE 802.15.4 Radio in Industrial Environment Mon, 29 Dec 2014 06:35:16 +0000 http://www.hindawi.com/journals/ijdsn/2014/240256/ IEEE 802.15.4 PHY has been widely used in wireless sensor networks. In-depth investigations on the link layer characteristics are important for WSN protocol design. In industrial environments, link reliability is vulnerable to various interferences; therefore, many schemes have been employed for reliability improvements such as multichannel access, frequency hopping, and multipath routing, which put forward the demand on link reliability models. Previous researches mainly focus on distance fading and irregularity of link reliability; however, little work analyses the temporal and frequency variations of the link reliability. The paper proposed a link layer statistical model (LTM) for time-varying of 16 channels based on packet drop rate (PDR) data collected from typical industrial environments. LTM descript packet drop intervals, PDR variation over times, PDR variation between different channels, link level switching probability and interference distribution. And also, a discussion of the influence of IEEE 802.15.4e MAC protocol simulation showed that LTM is closer to the realistic result. This paper provides a new method to model link reliability in industrial environment and is useful to the design of frequency diversity and upper layer protocols. Wan Yadong and Duan Shihong Copyright © 2014 Wan Yadong and Duan Shihong. All rights reserved. Cross-Layer QoS Optimization of Wireless Sensor Network for Smart Grid Sun, 28 Dec 2014 07:27:50 +0000 http://www.hindawi.com/journals/ijdsn/2014/327067/ Wireless Sensor Network (WSN) has been considered as a promising solution for Smart Grid due to the significant advantages over traditional communication technologies. However, as a necessary function for monitoring, diagnosing, and controlling of remote electrical equipment, Quality of Service (QoS) is still a challenging problem in applying WSN in Smart Grid. This paper presents a comprehensive experimental study on optimization of multiobject QoS in cross-layers of WSN protocol. In PHY layer, a Link Quality Estimator is studied for the purpose of evaluating link quality under harsh Smart Grid environments. In MAC layer, a QoS Enhanced MAC algorithm is used to prevent disorderly contentions among nodes and to allocate more channel resources for critical traffic; in NWK layer, a routing algorithm is introduced for multiobject QoS optimization. All the algorithms are cooperated with each other in cross-layer manner to improve end-to-end reliability and latency. In comparison with other counterparts, the proposed algorithms achieve preferable performances. Finally, field experiments were conducted, the result of which showed that the proposed algorithms outperform the ZigBee protocol and the original Distribution Grid wireless communication technology in terms of the QoS performance of critical traffic. Wei Sun and Jianping Wang Copyright © 2014 Wei Sun and Jianping Wang. All rights reserved. Protocols and Architectures for Next-Generation Wireless Sensor Networks Tue, 23 Dec 2014 07:13:48 +0000 http://www.hindawi.com/journals/ijdsn/2014/705470/ Sana Ullah, Joel J. P. C. Rodrigues, Farrukh Aslam Khan, Christos Verikoukis, and Zuqing Zhu Copyright © 2014 Sana Ullah et al. All rights reserved. Efficient Bi-Iterative Method for Source Position and Propagation Speed Estimation Using TDOA Measurements Tue, 23 Dec 2014 00:10:16 +0000 http://www.hindawi.com/journals/ijdsn/2014/689871/ This paper develops an efficient bi-iterative source location and propagation speed estimation method utilizing time difference of arrival (TDOA) measurements. The source location and propagation speed estimation is a nonlinear problem due to the nonlinearity in the TDOA measurement equations. The newly developed bi-iterative method computes the source location and propagation speed alternately. The asymptotic convergence of the new bi-iterative method is theoretically analyzed. First-order perturbation analysis is applied to the newly developed solution to derive its bias and variance. The first-order analytical results show that the proposed method provides approximately unbiased source position and propagation speed estimates for low noise levels and the accuracy of these estimates approaches the Cramer-Rao lower bound (CRLB). The extension of the new bi-iterative method to the more general situation where the sensor locations are subject to random errors is also presented. Simulation studies are given to show the good performance of the proposed method. Guo-Hui Zhu, Da-Zheng Feng, and Yan Zhou Copyright © 2014 Guo-Hui Zhu et al. All rights reserved. Multimedia Sensor Networks Tue, 23 Dec 2014 00:10:14 +0000 http://www.hindawi.com/journals/ijdsn/2014/573834/ Li Zhuo, Jie Liang, Zhiyong Wang, and Rong Ding Copyright © 2014 Li Zhuo et al. All rights reserved. Sensing with Mobile Wireless Sensor Networks Mon, 22 Dec 2014 12:56:46 +0000 http://www.hindawi.com/journals/ijdsn/2014/936830/ Zhongwen Guo, Minglu Li, Yu Wang, Lei Chen, and Feng Hong Copyright © 2014 Zhongwen Guo et al. All rights reserved. Decision Fusion Supported by Correlated Auxiliary Data in Wireless Sensor Networks Mon, 22 Dec 2014 08:12:34 +0000 http://www.hindawi.com/journals/ijdsn/2014/319093/ Leakage monitoring is different from sudden incident monitoring because most of the leakage cases involve a slow process that lasts for a long time. During this case monitoring, sensors suffer long exposure to erosion and may lead to errors in the measurement. An approach is proposed to make use of a soft-decision fusion approach according to the Neyman-Pearson criterion to accumulate auxiliary data from multiple sensors. The proposed method optimizes the soft-function and adjusts its range of sensors, which provide auxiliary data to improve the fusion center confidence for making a global decision. The new method encompasses the collection of useful data and weights and combines them according to the corresponding confidence level to make a global decision. In the simulation case of Rayleigh-distributed observations of leakage monitoring, it is proved that the proposed method has a good performance. Yu Bao, Xiexing Miao, Yanqun Zhang, and Aijuan Zhang Copyright © 2014 Yu Bao et al. All rights reserved. Spatial-Temporal Correlative Fault Detection in Wireless Sensor Networks Thu, 18 Dec 2014 00:11:07 +0000 http://www.hindawi.com/journals/ijdsn/2014/709390/ Wireless sensor networks (WSNs) have been used extensively in a range of applications to facilitate real-time critical decision-making and situation monitoring. Accurate data analysis and decision-making rely on the quality of the WSN data that have been gathered. However, sensor nodes are prone to faults and are often unreliable because of their intrinsic natures or the harsh environments in which they are used. Using dust data from faulty sensors not only has negative effects on the analysis results and the decisions made but also shortens the network lifetime and can waste huge amounts of limited valuable resources. In this paper, the quality of a WSN service is assessed, focusing on abnormal data derived from faulty sensors. The aim was to develop an effective strategy for locating faulty sensor nodes in WSNs. The proposed fault detection strategy is decentralized, coordinate-free, and node-based, and it uses time series analysis and spatial correlations in the collected data. Experiments using a real dataset from the Intel Berkeley Research Laboratory showed that the algorithm can give a high level of accuracy and a low false alarm rate when detecting faults even when there are many faulty sensors. Zhiping Kang, Honglin Yu, Qingyu Xiong, and Haibo Hu Copyright © 2014 Zhiping Kang et al. All rights reserved. Cooperative Target Localization and Tracking with Incomplete Measurements Thu, 18 Dec 2014 00:11:05 +0000 http://www.hindawi.com/journals/ijdsn/2014/906764/ This study investigates a problem on target localization and tracking for two cases where either the slant range information of dual stations is lost or the slant range information of one station and the pitch angle information of the other one are missing. The models of cooperative localization with incomplete measurements are presented and the Kalman filtering algorithm is applied for target tracking. For improving tracking precision, a strategy of observers path planning based on the gradient of circular error probability (CEP) is integrated into the Kalman filtering algorithm. Several numerical examples are used to illustrate the tracking performance of the proposed algorithm with the corresponding root mean square error (RMSE) and Cramer-Rao lower bound (CRLB). The Monte Carlo simulation results validate the effectiveness of the presented algorithm. Yi Zhang, Yinya Li, Guoqing Qi, and Andong Sheng Copyright © 2014 Yi Zhang et al. All rights reserved. Evolutionary Optimization Algorithms for Sunlight-Based Positioning Sensor Networks Wed, 17 Dec 2014 06:34:28 +0000 http://www.hindawi.com/journals/ijdsn/2014/564072/ The sunlight intensity-based global positioning system (SGPS) is able to geolocate outdoor objects by means of the sunlight intensity detection. This paper presents the integration of SGPS into a sensor network in order to improve the overall accuracy using evolutionary algorithms. Another contribution of the paper is to theoretically solve both global and relative positioning of the sensors composing the network within the same framework without satellite-based GPS technology. Results show that this approach is promising and has potential to be improved further. Jose Pardeiro, Javier V. Gómez, Alberto Brunete, and Frode Eika Sandnes Copyright © 2014 Jose Pardeiro et al. All rights reserved. 5 G WiFi Signal-Based Indoor Localization System Using Cluster -Nearest Neighbor Algorithm Wed, 17 Dec 2014 00:10:51 +0000 http://www.hindawi.com/journals/ijdsn/2014/247525/ Indoor localization based on existent WiFi signal strength is becoming more and more prevalent and ubiquitous. Unfortunately, the WiFi received signal strength (RSS) is susceptible by multipath, signal attenuation, and environmental changes, which is the major challenge for accurate indoor localization. To overcome these limitations, we propose the cluster -nearest neighbor (KNN) algorithm with 5 G WiFi signal to reduce the environmental interference and improve the localization performance without additional equipment. In this paper, we propose three approaches to improve the performance of localization algorithm. For one thing, we reduce the computation effort based on the coarse localization algorithm. For another, according to the detailed analysis of the 2.4 G and 5 G signal fluctuation, we expand the real-time measurement RSS before matching the fingerprint map. More importantly, we select the optimal nearest neighbor points based on the proposed cluster KNN algorithm. We have implemented the proposed algorithm and evaluated the performance with existent popular algorithms. Experimental results demonstrate that the proposed algorithm can effectively improve localization accuracy and exhibit superior performance in terms of localization stabilization and computation effort. Feng Yu, Minghua Jiang, Jing Liang, Xiao Qin, Ming Hu, Tao Peng, and Xinrong Hu Copyright © 2014 Feng Yu et al. All rights reserved. A Middleware for the Integration of Smart Grid Elements with WSN Based Solutions Tue, 16 Dec 2014 13:57:22 +0000 http://www.hindawi.com/journals/ijdsn/2014/506203/ Currently, electricity distributors make use of various types of equipment divided into levels of automation. This automation enables the integration of elements such as Intelligent Electronic Devices (IEDs) to the supervision of the distribution electrical system, but there is not an appropriate environment to increase the scale of these elements. In this context, the smart grid comes with specifications that allow adding new elements to the intelligence of the power grid operation. However, the cost of communication is still an impediment to the scalability of the integration of these elements into the current structure. In this paper, we propose a middleware that optimizes the communication of this integration using wireless sensor networks (WSN). The goal is to ensure a gradual integration of new elements taking advantage of the increase in the number of sensor nodes in the network due to the scalability of the system itself. The conversion solutions have been used to allow easy communication between the WSN and the smart grid system, and we also have used data aggregation and compression techniques to increase the lifetime of the wireless sensor network. Paulo Régis C. de Araújo, Raimir Holanda, Antonio Wendell de Oliveira Rodrigues, André Luiz Carneiro de Araújo, José de Aguiar Moraes Filho, and João Paolo C. M. Oliveira Copyright © 2014 Paulo Régis C. de Araújo et al. All rights reserved. Hybrid Fingerprinting-EKF Based Tracking Schemes for Indoor Passive Localization Mon, 08 Dec 2014 12:13:20 +0000 http://www.hindawi.com/journals/ijdsn/2014/351523/ This paper investigates a combination of fingerprinting (FP) and extended Kalman filter (EKF) based tracking aiming to tackle conventional problems related to implementation of either tracking or fingerprinting separately. One of the common drawbacks of FP belongs to large data size and consequent large search space. By taking advantage of latest position estimate got from EKF, a virtual surveillance area (VSA) is defined around the estimate. The dimension of this defined surveillance area is much smaller than the size of indoor environment. Consequently, there will be a possibility for FP to be applied in larger areas maintaining the possibility of adding necessary grid points in order to achieve a desired localization performance. Additionally, in order to improve accuracy of ranging, we investigate the impact of a priori knowledge related to the clusters impulse responses and other features; the applied so called soft ranging algorithm for time of arrival (TOA) estimation is modified in order to take advantage of this a priori information and to make its decision variables more accurate. Simulation results show a promising performance improvement via using the proposed hybrid tracking technique and applying a priori information to soft ranging. The tradeoff is along a reasonable increased implementation complexity. Salar Bybordi and Luca Reggiani Copyright © 2014 Salar Bybordi and Luca Reggiani. All rights reserved. Node Replication Attacks in Mobile Wireless Sensor Network: A Survey Mon, 08 Dec 2014 07:45:34 +0000 http://www.hindawi.com/journals/ijdsn/2014/402541/ Mobile wireless sensor networks (MWSNs) comprise a collection of mobile sensor nodes with confined and finite resources. They commonly operate in hostile environments such as battle fields and surveillance zones. Owing to their operating nature, MWSNs are often unattended and generally are not equipped with tamper-resistant tools. With little effort, an adversary may capture the nodes, analyze and replicate them, and surreptitiously insert these replicas at strategic locations within the network. Keeping in view of the above, this paper places an emphasis on this aforementioned attack, known as node replication attack in MWSNs. Specifically, the current state-of-the-art of node replication attack in MWSNs is discussed, where this paper provides a detailed description of various existing detection and prevention mechanisms in literature with an aim to provide better understanding of the factors that need to be considered when designing defence mechanism of node replication attack. A detailed categorization of various detection techniques is provided in the paper with critical discussion on each categorization with respect to its advantages, disadvantages, and various constraints. To conclude the paper, a number of parameters are selected for comparison and analysis of all the existing detection schemes in the literature. Haafizah Rameeza Shaukat, Fazirulhisyam Hashim, Aduwati Sali, and M. Fadlee Abdul Rasid Copyright © 2014 Haafizah Rameeza Shaukat et al. All rights reserved. Container Security Device Chain Network for Safe Railway Transportation Sun, 30 Nov 2014 00:10:31 +0000 http://www.hindawi.com/journals/ijdsn/2014/767802/ The railway is one of the most important facilities for freight logistics. This paper suggests the use of the container security devices (CSDs), which has been adopted for the marine transportation so far, to enhance the security of railway freight transportation. The proposed protocol, CSD Chain Network Protocol (CCNP), was designed for a chain-form network of CSDs, each of which is attached to a container. In CCNP, unauthorized access to freight is reliably reported to the reader deployed at the locomotive. CCNP also cares about the fairness in energy consumption. In a usual chain network, a tag closer to the reader consumes more energy since it ought to forward packets coming from rear tags as well. However, in CCNP, the tag energy consumption for packet forwarding is always the same regardless of the position in a chain owing to an efficient data fusion scheme. In our simulation using QualNet, CCNP reduces the number of disconnections between tags by 59.5% as compared to general chain networks. The energy consumption also decreases by 91.3% of other networks not using an aggregation method. Sungryul Kim, Jeonghyun Kim, and Younghwan Yoo Copyright © 2014 Sungryul Kim et al. All rights reserved.