International Journal of Distributed Sensor Networks The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. An Optimized Strategy Coverage Control Algorithm for WSN Wed, 23 Jul 2014 13:37:06 +0000 The problem of using lesser wireless sensor network nodes to achieve coverage and connection of certain areas under given coverage conditions is a priority and hotspot issue of WSN. For this reason, in this paper, an optimized strategy coverage control (OSCC) algorithm is proposed. First of all, a relation mapping model of sensor nodes and target nodes is established by OSCC which is based on geometric figure and related theories, probability theory, converge property, and so forth to complete effective reasoning and calculate certain network models. Secondly, OSCC makes efficient analysis of the calculating results figure out the least number of sensor nodes to cover specific monitoring area. Thirdly, OSCC picks out the optimal routing solution while conducting combinatorial optimization of routing path using ant colony optimization (ACO) algorithm, thus reducing the energy spending of whole network. In the end, this paper verifies OSCC algorithm by simulation experiment and proves it can use least sensor nodes to effectively cover target area. Also, OSCC helps greatly reduce network energy consuming, minimize network resources layout costs, and enhance network life cycle, simultaneously. Zeyu Sun, Weiguo Wu, Huanzhao Wang, Heng Chen, and Wei Wei Copyright © 2014 Zeyu Sun et al. All rights reserved. A Graph Embedding Method Based on Sparse Representation for Wireless Sensor Network Localization Wed, 23 Jul 2014 11:49:58 +0000 In accordance with the problem that the traditional trilateral or multilateral estimation localization method is highly dependent on the proportion of beacon nodes and the measurement accuracy, an algorithm based on kernel sparse preserve projection (KSPP) is proposed in this dissertation. The Gaussian kernel function is used to evaluate the similarity between nodes, and the location of the unknown nodes will be commonly decided by all the nodes within communication radius through selection of sparse preserve projection self-adaptation and maintaining of the topological structure between adjacent nodes. Therefore, the algorithm can effectively solve the nonlinear problem while ranging, and it becomes less affected by the measuring error and beacon nodes quantity. Xiaoyong Yan, Aiguo Song, and Hao Yan Copyright © 2014 Xiaoyong Yan et al. All rights reserved. Adaptive Quantization for Distributed Estimation in Energy-Harvesting Wireless Sensor Networks: A Game-Theoretic Approach Wed, 23 Jul 2014 09:21:31 +0000 The problem of distributed estimation in energy-harvesting wireless sensor networks (EH-WSNs) is studied. In general, the energy state of an energy-harvesting sensor varies dramatically. Existing efforts mainly concentrate on the problem of distributed estimation for battery-powered WSNs, ignoring the crucial issue of energy harvesting. Therefore, the unpredictable energy harvesting, the energy storage device, and energy consumption are modeled in a unified way to jointly address the energy harvesting and distributed estimation problem. In this paper, combining with the classical adaptive distributed estimation scheme, the problem of parameter estimation in EH-WSNs is formulated as a game of complete and perfect information. Each player decides its strategy according to the others’ energy states and actions. The subgame perfect equilibrium (SPE) is derived by backward induction. Simulation results show that the proposed SPE makes full use of the harvested energy and improves the estimation performance. Hua Liu, Guiyun Liu, Yonggui Liu, Lei Mo, and Hongbin Chen Copyright © 2014 Hua Liu et al. All rights reserved. Web Spider Defense Technique in Wireless Sensor Networks Wed, 23 Jul 2014 00:00:00 +0000 Wireless sensor networks (WSNs) are currently widely used in many environments. Some of them gather many critical data, which should be protected from intruders. Generally, when an intruder is detected in the WSN, its connection is immediately stopped. But this way does not let the network administrator gather information about the attacker and/or its purposes. In this paper, we present a bioinspired system that uses the procedure taken by the web spider when it wants to catch its prey. We will explain how all steps performed by the web spider are included in our system and we will detail the algorithm and protocol procedure. A real test bench has been implemented in order to validate our system. It shows the performance for different response times, the CPU and RAM consumption, and the average and maximum values for ping and tracert time responses using constant delay and exponential jitter. Alejandro Canovas, Jaime Lloret, Elsa Macias, and Alvaro Suarez Copyright © 2014 Alejandro Canovas et al. All rights reserved. A Method for Distributed Pipeline Burst and Leakage Detection in Wireless Sensor Networks Using Transform Analysis Tue, 22 Jul 2014 09:05:59 +0000 Bursts and leakages have turned out to be one of the most frequent malfunctions in liquid pipeline distribution systems. In recent years, the issue has gained a lot of attention in research community due to associated financial costs, environmental hazards, and safety considerations. Wireless sensor network (WSN) based leakage detection and localization can provide an exceptional level of operational efficiency, safety assurance, and real-time parametric view of the entire pipeline network. In this paper, we propose a transient pressure wave based technique coupled with wavelet analysis to achieve reliable detection and localization of abrupt bursts and leakages. The presented technique uses the information carried in the transient pressure signal. A specific pattern is induced on the pressure traces within the pipeline due to leak; we use wavelet analysis to detect these local singularities. The proposed algorithm is distributed in nature and run on low power sensor nodes. The algorithm is deployed in field on a custom pipeline test bed and performance results are documented for various testing scenarios. A comparison of proposed wavelet technique with other widely used methods has been carried out. The technique provides more than 90% accuracy in a number of deployment scenarios for high noise generating long pipeline networks. Sidra Rashid, Saad Qaisar, Husnain Saeed, and Emad Felemban Copyright © 2014 Sidra Rashid et al. All rights reserved. Proximity-Based Robust Event Detection in Wireless Sensor Networks Tue, 22 Jul 2014 06:14:00 +0000 This paper presents a proximity-based event detection scheme for wireless sensor networks. It is a hybrid scheme in the sense that it takes advantage of both neighbor-based and cluster-based schemes in distinguishing events from false alarms due to faulty nodes. It gives more weights to alarms in closer proximity, while making event decisions at the cluster heads to reduce the communication overhead. The proposed scheme can effectively reduce false alarms while accurately detecting events even for a relatively small event region. Simulation results show that it greatly lessens the tradeoff between event detection accuracy and false alarm rate. Further improvements in performance can be made by removing identified faulty nodes from the network during normal operation. Chan-O Hong and Yoon-Hwa Choi Copyright © 2014 Chan-O Hong and Yoon-Hwa Choi. All rights reserved. A Survey on Three-Dimensional Wireless Ad Hoc and Sensor Networks Mon, 21 Jul 2014 07:50:21 +0000 In parallel with steady research and development in ad hoc and wireless sensor networks, many testbeds have been implemented and deployed in real world. Furthermore, some research works have addressed design issues for deployment in three-dimensional space such as sky or ocean. Since many research challenges in three-dimensional spaces have not been explored yet as much as two dimensional spaces, it is required to define the challenging tasks to provide reliable communication in three-dimensional space. In this survey, we aim to identify the unique properties of communication environments in three-dimensional space and address the overview of the state of the art in this research area. To achieve this, the survey is organized according to two good example networks, airborne ad hoc networks (AANETs) and underwater wireless sensor networks (UWSNs). For each network, we introduce and review the related research works to focus on infrastructure, localization, topology design, and position-based routing. Finally, open research issues are also discussed and presented. Babar Shah and Ki-Il Kim Copyright © 2014 Babar Shah and Ki-Il Kim. All rights reserved. Does Human Finger’s Pressure Sensing Improve User Text Input on Mobile Device? A Study on Input Performance Improvement Based on Human Finger’s Pressure on Mobile Device Mon, 21 Jul 2014 00:00:00 +0000 This paper introduces a pressure-sensitive text input system that provides an easier and faster method for entering Korean in the rapidly expanding smartphone environment. In order to evaluate the effectiveness of the proposed system, a pressure-sensitive text input system is implemented and three Korean input experiments are conducted on mobile phones from the two largest manufacturers in South Korea (Samsung and LG). Whereas conventional Korean input methods used in Samsung and LG mobile phones require multiple touches for entering characters such as double consonants and diphthongs, the pressure-sensitive text input method allows the user to enter them with a single touch. Experimental results confirm that the proposed pressure-sensitive Korean input method was effective in reducing the number of touches required for entering consonants for Samsung’s text input method (47% reduction) and for entering vowels for LG’s text input method (20% reduction). Yoon Sang Kim and Junho Ko Copyright © 2014 Yoon Sang Kim and Junho Ko. All rights reserved. Adaptive Heterogeneous Network Handoff of Smartphone Based on the Closed Control Loop Sun, 20 Jul 2014 12:03:36 +0000 Owing to complementary characteristics of wireless networks, it is deserved to achieve automatic handoff on the modern smartphone for taking full exploitation of these accessible technologies. In this paper, we have proposed the closed loop model on smartphone switching heterogeneous wireless networks, which is full-client based without requiring additional support from the access points or gateways and modification of the network protocols. It only intuitively takes advantage of user scheme as the feedback adjustment approach to handoff policy. Furthermore, we have analyzed the closed loop handoff model to illustrate and evaluate how the user feedback of the policy acts on adapting to change context. In the experiment, we have evaluated four metrics on the closed loop handoff policy in real smartphone device: performance, energy saving, data offloading, and user experience. Wei Liu, Qiang Li, Yongle Chen, Yongping Xiong, Yubo Deng, and Limin Sun Copyright © 2014 Wei Liu et al. All rights reserved. Recognizing Boundaries in Wireless Sensor Networks Based on Local Connectivity Information Sun, 20 Jul 2014 07:19:18 +0000 This paper develops an efficient and distributed boundary detection algorithm to precisely recognize wireless sensor network (WSN) boundaries using only local connectivity information. Specifically, given any node in a WSN, the proposed algorithm constructs its 2-hop isocontour and locally makes a rough decision on whether this node is suspected to be on boundaries of the WSN by examining the associated 2-hop isocontour. Then, a heuristic operation is performed to refine this decision, with the result that the suspected boundary node set is significantly shrunk. Lastly, tight boundary cycles corresponding to both inner and outer WSN boundaries are derived by searching the suspected boundary node set. Furthermore, regarding WSNs with relatively low node densities, the proposed algorithm is adapted to improve the quality of boundary detection. Even though the proposed algorithm is initially presented under the assumption of the idealized unit disk graph (UDG) model, we further consider the more realistic quasi-UDG (QUDG) model. In addition, a message complexity analysis confirms the energy efficiency of the proposed algorithm. Finally, we carry out a thorough evaluation showing that our algorithm is applicable to both dense and sparse deployments of WSNs and is able to produce accurate results. Baoqi Huang, Wei Wu, Guanglai Gao, and Tao Zhang Copyright © 2014 Baoqi Huang et al. All rights reserved. Solar Energy Harvesting and Management in Wireless Sensor Networks Sun, 20 Jul 2014 00:00:00 +0000 Wireless networks comprise of small devices that are typically deployed in environments where paucity of energy seriously restricts essential operations. The energy source of these devices decreases very quickly during continuous operation and it is pivotal to replace or recharge frequently the power sources. Sometimes, it is very difficult to perform these functions through conventional methods. One attractive solution to this problem is the use of the energy, scattered around us in the environment. The availability of energy from the environment is random and uncertain. In this paper, we present a model, schematically and analytically, for solar energy harvesting with appropriate energy management. We provide analysis and simulations for a solar cell for standard and different irradiance levels. The power of the storage device is also simulated for different times of the day. The proposed model not only scavenges the energy but also assures the connectivity of the network by optimizing the energy consumption. Muhammad Mazhar Abbas, Mohamed A. Tawhid, Khalid Saleem, Zia Muhammad, Nazar Abbas Saqib, Hafiz Malik, and Hasan Mahmood Copyright © 2014 Muhammad Mazhar Abbas et al. All rights reserved. iAMCTD: Improved Adaptive Mobility of Courier Nodes in Threshold-Optimized DBR Protocol for Underwater Wireless Sensor Networks Sun, 20 Jul 2014 00:00:00 +0000 We propose forwarding-function () based routing protocol for underwater sensor networks (UWSNs): improved adaptive mobility of courier nodes in threshold-optimized depth-based-routing (iAMCTD). Unlike existing depth-based acoustic protocols, the proposed protocol exploits network density for time-critical applications. In order to tackle flooding, path loss, and propagation latency, we calculate optimal holding time () and use routing metrics: localization-free signal-to-noise ratio (LSNR), signal quality index (SQI), energy cost function (ECF), and depth-dependent function (DDF). Our proposal provides on-demand routing by formulating hard threshold (), soft threshold (), and prime energy limit (). Simulation results verify effectiveness and efficiency of the proposed iAMCTD. N. Javaid, M. R. Jafri, Z. A. Khan, U. Qasim, T. A. Alghamdi, and M. Ali Copyright © 2014 N. Javaid et al. All rights reserved. Selective Sensing and Access Strategy to Maximize Throughput in Cognitive Radio Sensor Network Thu, 17 Jul 2014 08:09:39 +0000 This paper presents a selective spectrum sensing and access strategy in a cognitive radio sensor network (CRSN), in order to maximize the throughput of secondary user (SU) system. An SU senses multiple channels simultaneously via wideband spectrum sensing. To maximize the throughput and reduce the sensing energy consumption, not all of the channels are sensed. The SU selects some channels for spectrum sensing and accesses these channels based on the sensing results. The unselected channels are accessed directly with low transmission power. A selection making algorithm based on partially observable Markov decision process (POMDP) theory is proposed, to make the SU determine which channels are selected for sensing, how long the sensing time, and the transmission powers of channels. An optimal policy and a myopic policy are proposed to solve the proposed POMDP problem. Moreover, an optimization problem is proposed to solve the synchronism problem among the selected channels. Numerical results show that the proposed selective spectrum sensing and access strategy improves the system performance efficiently. Weijun Li, Chao Yang, Zhenquan Wu, Beihai Tan, and Yuli Fu Copyright © 2014 Weijun Li et al. All rights reserved. An Intrusive Analyzer for Hadoop Systems Based on Wireless Sensor Networks Thu, 17 Jul 2014 07:40:44 +0000 Owing to the acceleration of IoT- (Internet of Things-) based wireless sensor networks, cloud-computing services using Big Data are rapidly growing. In order to manage and analyze Big Data efficiently, Hadoop frameworks have been used in a variety of fields. Hadoop processes Big Data as record values by using MapReduce programming in a distributed environment. Through MapReduce, data are stored in a Hadoop file system, and that form is not structured but unstructured. For this, it is not easy to grasp the cause, although inaccurate and unreliable data occur in the process of Hadoop-based MapReduce. As a result, Big Data may lead to a fatal flaw in the system, possibly paralyzing services. There are existing tools that monitor Hadoop systems’ status. However, the status information is not related to inner structure of Hadoop system so it is not easy to analyze Hadoop systems. In this paper, we propose an intrusive analyzer that detects interesting events to occur in distributed processing systems with Hadoop in wireless sensor networks. This tool guarantees a transparent monitor as using the JDI (Java debug interface). Byoung-Jin Bae, Young-Joo Kim, Young-Kuk Kim, Ok-Kyoon Ha, and Yong-Kee Jun Copyright © 2014 Byoung-Jin Bae et al. All rights reserved. Advances in Security and Privacy in Sensor Networks Thu, 17 Jul 2014 00:00:00 +0000 Fatos Xhafa, Jin Li, Duncan S. Wong, and Francesco Palmieri Copyright © 2014 Fatos Xhafa et al. All rights reserved. Modeling the Performance of Faulty Linear Wireless Sensor Networks Wed, 16 Jul 2014 12:59:01 +0000 Wireless sensor networks (WSNs) are used to monitor long linear structures such as pipelines, rivers, railroads, international borders, and high power transmission cables. In this case, a special type of WSN called linear wireless sensor network (LSN) is used. One of the main challenges of using LSNs is the reliability of the connections across the nodes. Faults in a few contiguous nodes may cause the creation of holes (segments where nodes on either end of them cannot reach each other) which will result in dividing the network into multiple disconnected segments. As a result, sensor nodes that are located between holes may not be able to deliver their sensed information which negatively affects the network’s sensing coverage. In this paper, we provide an analysis of the different types of node faults in uniformly deployed LSNs and study their negative impact on the sensing coverage. We develop an analytical model to estimate the sensing coverage in uniformly deployed sensors LSNs in the presence of node faults. We verify the correctness of the developed model by conducting a number of simulation experiments to compare both calculated and simulated results under different network configurations and fault scenarios. In addition, we use this model to demonstrate three design applications that meet with specific performance requirements. Nader Mohamed, Jameela Al-Jaroodi, and Imad Jawhar Copyright © 2014 Nader Mohamed et al. All rights reserved. Real-Time 3D Simulation for the Trawl Fishing Gear Based on Parallel Processing of Sonar Sensor Data Wed, 16 Jul 2014 12:06:37 +0000 A huge and a complex internal computation is required to visualize the underwater geometry of a fishing gear, because each particle of the gear should be calculated with consideration of several force vectors, such as the movements of the fishing vessel, the buoyancy of the gear, and the tension of pulling or pursing acting on the net panels. The internal computation is the main drawback for providing a real-time visualization that takes into account the force vectors and the changes of underwater environments which can be obtained from the multiple sonar sensors. This paper presents a three-dimensional (3D) visualization tool that offers real-time simulations of the trawl fishing gear using parallel processing for the particles applying the force vectors. This tool also offers different underwater geometries for each fishing gear through a multiview display. The tool employs OpenMP APIs and OpenGL libraries to calculate in parallel the particles and to draw the underwater shapes of fishing gears, respectively. This work can be applied to other simulation systems for analyzing the precise model of graphical geometries as well as modeling the underwater shapes of fishing gears. Myeong-Chul Park, Ok-Kyoon Ha, Seok-Wun Ha, and Yong-Kee Jun Copyright © 2014 Myeong-Chul Park et al. All rights reserved. Data Security and Privacy in Cloud Computing Wed, 16 Jul 2014 12:05:24 +0000 Data security has consistently been a major issue in information technology. In the cloud computing environment, it becomes particularly serious because the data is located in different places even in all the globe. Data security and privacy protection are the two main factors of user’s concerns about the cloud technology. Though many techniques on the topics in cloud computing have been investigated in both academics and industries, data security and privacy protection are becoming more important for the future development of cloud computing technology in government, industry, and business. Data security and privacy protection issues are relevant to both hardware and software in the cloud architecture. This study is to review different security techniques and challenges from both software and hardware aspects for protecting data in the cloud and aims at enhancing the data security and privacy protection for the trustworthy cloud environment. In this paper, we make a comparative research analysis of the existing research work regarding the data security and privacy protection techniques used in the cloud computing. Yunchuan Sun, Junsheng Zhang, Yongping Xiong, and Guangyu Zhu Copyright © 2014 Yunchuan Sun et al. All rights reserved. Route Prediction Based Vehicular Mobility Management Scheme for VANET Wed, 16 Jul 2014 09:57:49 +0000 Since improvement of wireless communication, IP based mobility management protocols have been studied to provide seamless communication and mobility management. The vehicular ad hoc network (VANET) is one of mobility management protocols, especially providing seamless connection with inter/intra/inner vehicle communication. However, each vehicle moves fast that causes short-lived connections with Access Router (AR). Based on vehicles’ characteristic, it is hard to provide the availability of IP services in VANET. The most critical issue of the design of scalable routing algorithm is to provide robustness of frequent path disruption caused by vehicles' mobility. In this paper, we pursue the characteristics of vehicles’ mobility and analyze them. With the navigation information which is one of vehicles’ mobility characteristics, we classify the mobility into intrahighway mobility and global mobility management. Furthermore, we propose mobility management scheme based on route prediction in VANET. Handoffs with intrahighway mobility are managed locally and transparency is provided to CHs, while global mobility is managed with Mobile IPv6. Finally, through the numerical analysis, we show that proposed mobility management protocol reduces handoff latency, signaling costs, and packet loss. DaeWon Lee, Yoon-Ho Kim, and HwaMin Lee Copyright © 2014 DaeWon Lee et al. All rights reserved. Histogram Estimation for Optimal Filter Skyline Query Processing in Wireless Sensor Networks Tue, 15 Jul 2014 14:11:32 +0000 The skyline query processing technique plays an increasingly important role for multicriteria decision making applications in wireless sensor networks. The technique of saving energy to prolong the lifetime of sensor nodes is one of the dominating challenges to resource-constrained wireless sensor networks. In this paper, we propose an energy-efficient skyline query processing algorithm, called the histogram filter based algorithm (HFA), to efficiently retrieve skyline results from a sensor network. First, we use historical data at the base station to construct histograms for further estimating the probability density distributions of the sensor data. Second, the dominance probability of each tuple is computed based on the histograms, and the optimal tuple which has the largest possibility of dominance/filtering capability is obtained using in-network aggregation approach. After that, the base station broadcasts the optimized tuple as the global filter to each sensor node. Then, the tuples which do not satisfy the skyline query semantics are discarded to avoid unnecessary data transmissions. An extensive experimental study demonstrates that the proposed HFA algorithm performs more efficiently than existing algorithms on reducing data transmissions during skyline query processing, which saves the energy and prolongs the lifetime of wireless sensor networks. Haixiang Wang, Jiping Zheng, Baoli Song, and Yongge Wang Copyright © 2014 Haixiang Wang et al. All rights reserved. for Helping People with Different Disabilities Tue, 15 Jul 2014 12:23:40 +0000 This paper introduces a monitoring and navigation system to help people with disabilities (). The proposed system is based on wireless sensor networks. In the system, each disabled person uses a handheld smart phone device. Three types of disabilities are studied in this paper: (1) blind, (2) deaf, and (3) on wheelchair. We experimented with a three-floor university building. Sensor nodes and cameras are scattered in all rooms and hallways. Smart phones are used to communicate with the sensor nodes to take instructions to navigate through the appropriate path. Dijkstra’s algorithm is used for navigation. also monitors the disabled person while navigating. The proposed system is compared to a baseline reference experiment. Results show improvement of 34% compared to the baseline reference experiment. Wael Hosny Fouad Aly Copyright © 2014 Wael Hosny Fouad Aly. All rights reserved. Wireless Sensor Networks Energy Effectively Distributed Target Detection Tue, 15 Jul 2014 12:05:21 +0000 The target detection is a kind of very important application of wireless sensor networks. In this paper, we propose an energy effective distributed multisensor target detection method, which is different from the existing single sensor target detection methods, and target is detected by multisensor cooperation scheme. The first algorithm presents a method of the time series discretization to solve the distance of the target detected by the first connected node. The detected information is aggregated in the aggregating node, and the optimal path by the second algorithm is built up to transmit the aggregated packets to the sink. According to the simulation results, the probability of the single node target detection is compared with that of the multisensor collaborative target detection, and the influence of the weight coefficient on average node energy consumption is analyzed. Furthermore, we provide the optimal data sampling period of target detection data. Xiaogang Qi, Peng Wei, Lifang Liu, Mande Xie, and Guoyong Cai Copyright © 2014 Xiaogang Qi et al. All rights reserved. A Framework for Obesity Control Using a Wireless Body Sensor Network Tue, 15 Jul 2014 11:52:08 +0000 Low-cost low-power consumption small wireless sensor devices have empowered the development of wireless body area networks (WBANs). In WBANs many sensors are attached to human body for sensing particular health related information to improve healthcare and quality of life. Obesity is one of the most common problems all over the world, which is amongst main causes of cardiovascular diseases. In this research, we explore hardware and software architecture of WBAN for obesity monitoring. The proposed framework consists of few sensor nodes that monitor body motion, calories calculator, and a personal server running on a personal smart phone or a personal computer. The focus of this research is to make obesity patients easier to get rid of this disease. Nabil Ali Alrajeh, Jaime Lloret, and Alejandro Canovas Copyright © 2014 Nabil Ali Alrajeh et al. All rights reserved. Load Balanced Routing for Lifetime Maximization in Mobile Wireless Sensor Networks Tue, 15 Jul 2014 09:05:41 +0000 Challenge of efficient protocol design for energy constrained wireless sensor networks is addressed through application specific cross-layer designs. This design approach along with strong design assumptions limits application of protocols in universal scenarios and affects their practicality. With proliferation of embedded mobile sensors in consumer devices, a changed application paradigm requires generic protocols capable of managing greater device heterogeneousness and mobility. In this paper, we propose a novel lifetime maximization protocol for mobile sensor networks with uncontrolled mobility considering residual energy, traffic load, and mobility of a node. The protocol being generic is equally applicable to heterogeneous, homogenous, static, and mobile sensor networks. It can handle event driven as well as continuous traffic flow applications. Simulation results show that proposed scheme outperforms minimum hop routing and greedy forwarding in terms of network lifetime, data packet latency, and load balance while maintaining comparable throughput. Saifullah Khalid, Ashraf Masood, Faisal Bashir Hussain, Haider Abbas, and Abdul Ghafoor Copyright © 2014 Saifullah Khalid et al. All rights reserved. Locating Anchors in WSN Using a Wearable IMU-Camera Tue, 15 Jul 2014 06:39:37 +0000 Localization in a wireless sensor network (WSN) becomes important for many modern applications, like landslide detection, precision agriculture, health care, and so forth. The more precise the position of an anchor node is, the more accurate the localization of a sensor node can be measured. Since the Global Positioning System (GPS) device cannot work properly indoor, some existing localization methods configure anchor nodes in a manual fashion. However, neither applying GPS modules nor manually configuring anchor nodes is suitable for a WSN and especially artificial errors of manual configuration may be propagated and affect the results of localization. In this paper, we propose an alternative method to estimate anchor node locations in an indoor environment. We collect the Received Signal Strength Indicator (RSSI) data from the anchor node when human is walking around them. Meanwhile, we use a wearable IMU-camera device to assist the moving trajectory estimation. We implement a monocular Visual Odometry with a human walking model to estimate moving trajectories. An Unscented Kalman Filter (UKF) is used to estimate the anchor node location by fusing the RSSI data and moving trajectory. The experiment results show that the proposed method has lower estimation error when locating anchors. Jwu-Sheng Hu, Yu-Lun Huang, and Chin-Yuan Tseng Copyright © 2014 Jwu-Sheng Hu et al. All rights reserved. REALFLOW: Reliable Real-Time Flooding-Based Routing Protocol for Industrial Wireless Sensor Networks Tue, 15 Jul 2014 00:00:00 +0000 Wireless technologies have been increasingly applied in industrial automation systems due to flexible installation, mobility, and cost reduction. Unlike traditional wireless sensor networks (WSNs), industrial wireless sensor networks (IWSNs), when expanding from wireless monitoring to wireless control, have more stringent requirements on reliability, real-time performance, and robustness in a number of industrial applications. Successive transmission failures or deadline misses in these applications may severely degrade the control quality and result in serious economic losses and safety problems. Therefore, when deploying IWSNs in harsh industrial environments, to achieve reliable and deterministic end-to-end transmissions is critically important. In this paper, we explain the primary challenges of designing appropriate routing protocols and present a reliable real-time flooding-based routing protocol for IWSNs (REALFLOW). Instead of traditional routing tables, related node lists are generated in a simple distributed manner, serving for packet forwarding. A controlled flooding mechanism is applied to improve both reliability and real-time performance. A seamless transition in the event of topology change can be achieved by REALFLOW. Performance evaluations via simulations verify that significant improvements of reliability, real-time performance, and network recovery time can be achieved by REALFLOW, compared with traditional routing protocols. Kan Yu, Zhibo Pang, Mikael Gidlund, Johan Åkerberg, and Mats Björkman Copyright © 2014 Kan Yu et al. All rights reserved. Underwater Image Gathering by Utilizing Stationary and Movable Sensor Nodes: Towards Observation of Symbiosis System in the Coral Reef of Okinawa Mon, 14 Jul 2014 12:04:57 +0000 This paper describes the underwater data collection utilizing stationary sensor node and movable sensor node. We consider applying the system to investigate the conditions of marine ecosystem around the coral reef at Okinawa, Japan. The framework and fundamental design of our proposed underwater information gathering system under development are introduced. It is also reported the development of the prototypes of the sensory node and movable sensor node. Basic examinations utilizing such prototype at underwater environment are also described. This paper also describes experimental results of image gathering from via wireless local area network communication. Our future trials based on the current developmental situation are also discussed. Kuniaki Kawabata, Fumiaki Takemura, Tsuyoshi Suzuki, Kei Sawai, Eisuke Kuraya, Satoru Takahashi, Hideyuki Yamashiro, Naoko Isomura, and Jianru Xue Copyright © 2014 Kuniaki Kawabata et al. All rights reserved. Voltage-Aware Time Synchronization for Wireless Sensor Networks Mon, 14 Jul 2014 09:55:19 +0000 The low-cost crystal oscillators in wireless sensor networks are prone to be affected by their working conditions such as voltage, temperature, and humidity. Such effect is often ignored by existing time synchronization solutions that typically assume the frequency error of a given node to be constant and hence adopt frequent timestamp exchanges, resulting in high energy consumptions. We propose a novel voltage-aware time synchronization (VATS) scheme that is inspired by the fact that the clock skew is highly correlated to voltage supplies. VATS features a two-phase process: (i) it first estimates the clock skew and updates the frequency error autonomously based on the local voltage level; (ii) it then adjusts the resynchronization intervals dynamically according to a given synchronization error controlling factor and the synchronization error accumulating rate to balance the calibration accuracy and cost. Since VATS leverages voltage measurements to assist clock skew estimation, it does not require frequent timestamp exchanges as in traditional schemes. Extensive simulation results illustrate the superior performance of the proposed method in terms of calculation accuracy, robustness, and reduced timestamp exchanges for energy saving. Meng Jin, Dingyi Fang, Xiaojiang Chen, Zhe Yang, Chen Liu, and Xiaoyan Yin Copyright © 2014 Meng Jin et al. All rights reserved. Spectrum Distribution in Cognitive Radio: Error Correcting Codes Perspective Mon, 14 Jul 2014 00:00:00 +0000 Cognitive radio is a growing zone in wireless communication which offers an opening in complete utilization of incompetently used frequency spectrum: deprived of crafting interference for the primary (authorized) user, the secondary user is indorsed to use the frequency band. Though, scheming a model with the least interference produced by the secondary user for primary user is a perplexing job. In this study we proposed a transmission model based on error correcting codes dealing with a countable number of pairs of primary and secondary users. However, we obtain an effective utilization of spectrum by the transmission of the pairs of primary and secondary users’ data through the linear codes with different given lengths. Due to the techniques of error correcting codes we developed a number of schemes regarding an appropriate bandwidth distribution in cognitive radio. Syed Azmat Hussain, Tariq Shah, Naveed Ahmed Azam, Antonio Aparecido de Andrade, and Aqdas Naveed Malik Copyright © 2014 Syed Azmat Hussain et al. All rights reserved. PAuthKey: A Pervasive Authentication Protocol and Key Establishment Scheme for Wireless Sensor Networks in Distributed IoT Applications Sun, 13 Jul 2014 00:00:00 +0000 Wireless sensor Networks (WSNs) deployed in distributed Internet of Things (IoT) applications should be integrated into the Internet. According to the distributed architecture, sensor nodes measure data, process, exchange information, and perform collaboratively with other sensor nodes and end-users, which can be internal or external to the network. In order to maintain the trustworthy connectivity and the accessibility of distributed IoT, it is important to establish secure links for end-to-end communication with a strong pervasive authentication mechanism. However, due to the resource constraints and heterogeneous characteristics of the devices, traditional authentication and key management schemes are not effective for such applications. This paper proposes a pervasive lightweight authentication and keying mechanism for WSNs in distributed IoT applications, in which the sensor nodes can establish secured links with peer sensor nodes and end-users. The established authentication scheme PAuthKey is based on implicit certificates and it provides application level end-to-end security. A comprehensive description for the scenario based behavior of the protocol is presented. With the performance evaluation and the security analysis, it is justified that the proposed scheme is viable to deploy in the resource constrained WSNs. Pawani Porambage, Corinna Schmitt, Pardeep Kumar, Andrei Gurtov, and Mika Ylianttila Copyright © 2014 Pawani Porambage et al. All rights reserved.