International Journal of Distributed Sensor Networks The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Energy and Spectrum Efficient Wireless Sensor Networks Mon, 06 Jun 2016 12:33:44 +0000 Gianni Pasolini, George Alexandropoulos, Lorenzo Mucchi, Javier Prieto, and Yuan Shen Copyright © 2016 Gianni Pasolini et al. All rights reserved. An Optimized Data Obtaining Strategy for Large-Scale Sensor Monitoring Networks Mon, 06 Jun 2016 12:05:00 +0000 As the technology of the Internet of Things (IoT) becomes more widely used in large-scale monitoring networks, this paper proposes an optimized obtaining strategy (OFS) for large-scale sensor monitoring networks. First, because of the large-scale features of sensor node network, this paper proposes a large-scale monitoring network area clustering optimization strategy. Second, based on the characteristics of regular changes in the sensed data in large-scale monitoring networks, this paper proposes a strategy for acquiring sensor data based on an adaptive frequency conversion. The OFS optimization strategy can prolong network lifetime, reduce the transmission bandwidth resources, and reduce average energy consumption of the cluster head and network energy consumption. Yan Wang, Junlu Wang, Fengtong Wang, Ling Wang, and Wei Wei Copyright © 2016 Yan Wang et al. All rights reserved. Cooperative Secure Transmission in the Presence of Untrusted Relay Mon, 06 Jun 2016 11:13:53 +0000 Considering a nonregenerative untrusted relay network, we investigate three different secure transmission strategies, for example, noncooperative strategy, conventional amplify-and-forward (AF) strategy, and cooperative jamming (CJ) strategy. To thoroughly assess the secrecy performance achieved by the three strategies, we derive the closed-form expressions for the connection outage probability and secrecy outage probability regarding each strategy. Based on these expressions, the reliability and security tradeoff (RST) is examined to facilitate the design of the transmitting parameters. We then present the closed-form expression for the effective secrecy throughput (EST) and characterize the overall efficiency of these transmission strategies. Furthermore, we conduct the asymptotic analysis for the secrecy throughput, which enables us to determine the optimal transmission strategy under different scenarios. Our analytical and numerical results demonstrate that compared with the noncooperative and AF strategies, the CJ strategy possesses the best performance in terms of RST. Additionally, we also find that the EST performance of the AF strategy is nearly invariable when the quality of the second hop changes. Dechuan Chen, Weiwei Yang, Jianwei Hu, Yueming Cai, and Sen Zhu Copyright © 2016 Dechuan Chen et al. All rights reserved. On Harvesting Energy from Tree Trunks for Environmental Monitoring Mon, 06 Jun 2016 06:28:58 +0000 This work describes an experimental study on the possibilities of harvesting energy from tree trunks in order to power sensor nodes for environmental monitoring, particularly in wild forests. As the trunk of a living tree can be divided into isothermal subvolumes, which are generally referred to as annual rings, and the trunk is a good heat storage material, depending on the tree dimensions and its species, it can potentially offer different temperature gradients according to the tree trunk depths. The hypothesis is to consider the application of this temperature gradient on the faces of a Peltier cell to obtain electrical energy. In order to evaluate this hypothesis, a wireless sensor network was developed for measuring internal temperature of trunks from different trees. The experimental results show that it is possible to obtain a sufficient temperature gradient to harvest energy from tree trunks. Additionally, it is also shown that it is possible to harvest thermal energy during the day and during the night while photovoltaic cell only works under sunlight. Cleonilson P. Souza, Fabrício B. S. Carvalho, Filype A. N. Silva, Hening A. Andrade, Nathália de V. Silva, Orlando Baiocchi, and Ivan Müller Copyright © 2016 Cleonilson P. Souza et al. All rights reserved. OCC-ID: New Broadcasting Service-Based Cloud Model and Image Sensor Communications Sun, 05 Jun 2016 14:11:21 +0000 In recent decades, the main data traffic of mobile communication is based on the RF technology. Even though the efficiency from optimization for utilization or reuse is applied, there is a limitation of increased traffic demand of RF communication. Visible light communication (VLC) is a new technology that can cooperate with RF to address this limitation. The standard for VLC was published in 2011 as IEEE 802.15.7, which defined the specifications for the MAC layer and the PHY layer. This standard was one of the first for this technology. The decoded operation from emitting light at the receiver in IEEE 802.15.7 is mainly based on the photodetector. However, with the development of image sensors (matrix of photodiodes) on smart devices, the amendment of IEEE 802.15.7 specification is considered. The extension will focus mainly on image sensor communications, named optical camera communications (OCC). In this paper, we analyze the performance of a camera communications system based on different types of image sensor architecture. Then, we suggest OCC-ID, a new application for broadcasting service using camera communications and the cloud model. The proposed architecture is a typical deployment scenario of camera communications. Thithanhnhan Le, Nam-Tuan Le, and Yeong Min Jang Copyright © 2016 Thithanhnhan Le et al. All rights reserved. BigLoc: A Two-Stage Positioning Method for Large Indoor Space Sun, 05 Jun 2016 11:58:06 +0000 With the rapid development of WLAN infrastructure, fingerprint-based positioning using signal strength has become a promising localization solution in indoor space. Commonly fingerprint-based positioning methods face two challenges in large indoor space, one is floor recognition in large building with multifloor, and the other is signal strength variance due to heterogeneous devices and environmental factors. In this paper, we propose a novel two-stage positioning approach to address these challenges of fingerprint-based positioning methods in large indoor space. Firstly, we design a floor-level recognition feature based on WiFi access points and the RSS values to recognize floor. For solving the signal strength variance problem, we propose a new metric to capture the similarity of location fingerprints probability distribution using KL Divergence. To demonstrate the utility of our approach, we have performed comprehensive experiments in a large indoor building. Zengwei Zheng, Yuanyi Chen, Sinong Chen, Lin Sun, and Dan Chen Copyright © 2016 Zengwei Zheng et al. All rights reserved. Strong -Barrier Coverage for One-Way Intruders Detection in Wireless Sensor Networks Thu, 02 Jun 2016 13:15:46 +0000 Intruders detection is one of the very important applications in Wireless Sensor Networks (WSNs). Sometimes detecting intruders is not sufficient; distinguishing whether an intruder is legal or illegal is necessary. Since -barrier coverage is widely used in detecting intruders, a barrier construction algorithm is needed, which can not only detect an intruder but also judge an illegal intruder. An intruder is defined as illegal if and only if it crosses straightly through the monitored region from the special side to another side. On the contrary, it is a legal intruder. To detect an intruder and distinguish whether the intruder is legal or illegal, a strong -barrier coverage algorithm is proposed. The strong -barrier coverage is a local barrier constructing algorithm and can detect any intruder crossing the -barrier with a full probability. The strong -barrier coverage detects all intruders penetrating the annular region for times. What is more, the proposed strong -barrier algorithm can provide a reliable judgement on whether an intruder is legal or illegal, and the constructed -barrier coverage is different from the traditional one-way barrier coverage using binary barriers that are intersected but not overlapped. Some simulation tests show that the proposed algorithm can construct strong -barrier coverage very well. Junhai Luo and Shihua Zou Copyright © 2016 Junhai Luo and Shihua Zou. All rights reserved. Multiagent Semantical Annotation Enhancement Model for IoT-Based Energy-Aware Data Thu, 02 Jun 2016 09:10:39 +0000 The Internet of Things (IoT) is involved in dealing with physical items, gadgets, vehicles, structures, and different things that are inserted into hardware, programming, sensors, and system availability, which empowers these items to gather and trade information. Improving extraction of sensor-based data for energy awareness and then annotating it and converting it into semantically enabled form for analyzing results with the use of improved tools and applications are the focus of this research. However, as the amount of real time data gets huge, it becomes difficult to track results when needed at once. Reconciliation of heterogeneous information sources into an interlinked data is a standout among the most pertinent difficulties for some learning based systems these days. This paper forms suitable elements by a methodology for adjustment of heterogeneous sensor-based Web assets, where different tools and applications like weather detection for self-observing and self-diagnostics use dispersed human specialists and learning. The proposed general model uses a capability of the Semantic Web innovation and concentrates on the part of a semantic adjustment of existing broadly utilized models of information representation to Resource Description Framework (RDF) based semantically rich arrangement. This work is valuable for sorting out and inquiry of the detecting information in the Internet of Things. Kaleem Razzaq Malik, Tauqir Ahmad, Muhammad Farhan, Farhan Ullah, Kashif Amjad, and Shehzad Khalid Copyright © 2016 Kaleem Razzaq Malik et al. All rights reserved. Application of Vehicle Mounted Accelerometers to Measure Pavement Roughness Thu, 02 Jun 2016 05:55:08 +0000 To enhance the efficiency of pavement roughness measurement and reduce the cost, an integrated and wireless transfer based measuring system was developed. The proposed system can obtain vehicles status and location data via wireless acceleration sensors and GPS, calculate the international roughness index (IRI) by power spectral density analysis, and provide reports automatically. This paper presents the architecture of the proposed system, consisting of data collector, car mounted terminal, and information platform. Two wireless communication systems (ZigBee and 3G modules) were utilized to transfer the data and construct network between the components. The information platform implemented an acceleration-IRI model to calculate IRI, and a GPS based distance algorithm was employed to segment the measured road per 1 km. The various results are saved in an Oracle database, displayed on the digital map and made available to the mobile terminal. Several field tests of the prototype system were conducted in Huzhou, Zhejiang province in China. The results show that, compared to the laser roughness testing method, the relative error of this proposed system is less than 10%, which verifies the accuracy, effectiveness, and reliability of the proposed measuring system. Yuchuan Du, Chenglong Liu, Difei Wu, and Siyu Li Copyright © 2016 Yuchuan Du et al. All rights reserved. Leveraging In-Network Caching in Vehicular Network for Content Distribution Wed, 01 Jun 2016 13:24:27 +0000 Information-Centric Networking advocates ubiquitous in-network caching to enhance content distribution. Nonsafety application in vehicular communications is emerging beyond the initial safety application. However, content distribution based on TCP/IP Internet service in vehicular networks suffers from typical issue of low delivery ratio in urban environments, where high buildings block or attenuate the radio propagation as well as short radio coverage range. In order to solve this issue to deliver proximity marketing files, in this paper we propose in-network caching scheme in vehicular networks in accordance with traffic features, in which every vehicle is treated as either a subscriber to request a file or as a cache node to supply other nodes so as to accelerate file transmission effectively. Cache strategy of leave copy everywhere is uncoordinated and distributed, which fits the random and dynamic vehicular network. The performance evaluation is carried out by comparing the proposed scheme with the legacy solution of TCP/IP based scheme using simulation tools of OMNeT++ and Veins and SUMO, which is supplied with real-world urban map associated with random but reasonable traffic routes generated by our designed software for every vehicle. The simulation results validate the proposed scheme in four aspects: robustness resisting obstacle buildings, reliability and scalability in different traffic loads, low utilization ratios of RSUs and Internet resource, and efficiency of cache functions. Haiyan Tian, Yusuke Otsuka, Masami Mohri, Yoshiaki Shiraishi, and Masakatu Morii Copyright © 2016 Haiyan Tian et al. All rights reserved. Beyond the Internet of Things: The Social Networking of Machines Wed, 01 Jun 2016 08:23:16 +0000 Communication is a prerequisite for any form of social activity, including social networking. Nowadays, communication is not reserved only for humans, but machines can also communicate. This paper reviews the state-of-the-art technology in the area of Machine-to-Machine (M2M) communication by comparing the M2M concept with other related research paradigms such as Wireless Sensor Networks, Cyber-Physical Systems, Internet of Things, and Human-Agent Collectives. Furthermore, the paper analyses trends in the interconnecting of machines and identifies an evolutionary path in which future (smart) machines will form mostly or completely autonomous communities bonded through social connections. Such communities—machine social networks—will be formed dynamically, just like human connections, and based on the needs of machines, their context, and state of their environment. Finally, the paper outlines the current evolutionary stage and identifies key research challenges of machine social networking. Marina Pticek, Vedran Podobnik, and Gordan Jezic Copyright © 2016 Marina Pticek et al. All rights reserved. A Topology Controlling Scheme Based on Guard Region in Wireless Sensor Network Tue, 31 May 2016 14:44:34 +0000 In dense wireless sensor network, we usually remove the unnecessary communication links by topology control in order to get an energy efficient routing. The channel environment becomes more complex, which results in difficulty to control topology under a mass node distribution according to the accurate interference model. This paper introduces the concept of a guard region, defined as the region around each receiver where interfering transmissions are inhibited to make the topology control. Based on the hard-core process in stochastic geometry, the scheduling of interfering node in guard region and the density of active sensors are achieved theoretically. Then we do the analysis of coverage of receiver; the interference around receiver is computed as main interference in guard region and secondary interference outside guard region. Finally, through Monte-Carlo simulation, the topology model based on guard region is proved to be correct and the influences on coverage under different parameters are analyzed. Xiaojuan Wang, Lin Kang, Jingwen You, and Mei Song Copyright © 2016 Xiaojuan Wang et al. All rights reserved. Smart Grid: ICT Control for Distributed Energy Resources Mon, 30 May 2016 10:30:04 +0000 Jose Ignacio Moreno, Manel Martínez-Ramón, Pedro S. Moura, Javier Matanza, and Gregorio López Copyright © 2016 Jose Ignacio Moreno et al. All rights reserved. lwAKE: A Lightweight Authenticated Key Exchange for Class 0 Devices Mon, 30 May 2016 10:14:20 +0000 Device-to-Device (D2D) communication enables devices in proximity to establish a wireless direct link. However, these devices may be severely constrained in terms of memory, CPU, and processing resources. Hence, a D2D communication with a constrained device implies new challenges as it does not have the resources required to be secured with standard cryptography. We propose lwAKE for class 0 devices (RFC 7228), which uses one-way cryptographic functions and zero-knowledge proofs to provide mutual authentication and a secure key establishment. We specify the protocol using the High Level Protocol Specification Language and then verify the security properties using the model checkers OFMC and CL-AtSe. The significance of the protocol stands in a key reuse for any successive authentication. Experimental results show that this shortened authentication mode reduces the computational load greatly. Juan Jose Echevarria, Jon Legarda, Janire Larrañaga, and Jonathan Ruiz-de-Garibay Copyright © 2016 Juan Jose Echevarria et al. All rights reserved. Enhanced SDIoT Security Framework Models Mon, 30 May 2016 07:07:18 +0000 Following the recent increase in the interest in IoT (Internet of Things) environment, devices that provide various services are being developed. As the diversity, research is required for efficient management of these devices and enhanced security. Previous network environments tend to be dependent on network devices and have difficulties in active processing of variable traffic. Moreover, it is expected that new or variant attacks will increase as packets of various patterns are generated from numerous devices, and hence immense research effort is required in solving this problem. In order to address such problems, this study aims to investigate strategies for establishing a security framework for the configuration of a software-defined IoT environment and efficient provision of security services. Moreover, the service to reduce the overhead involved in security service provision is configured, and a simple test is conducted to verify the feasibility of the proposed model. Seongho Choi and Jin Kwak Copyright © 2016 Seongho Choi and Jin Kwak. All rights reserved. Constructing Maximum-Lifetime Data-Gathering Tree in WSNs Based on Compressed Sensing Sun, 29 May 2016 14:26:35 +0000 Data gathering is one of the most important operations in many wireless sensor networks (WSNs) applications. In order to implement data gathering, a tree structure rooted at the sink is usually defined. In most wireless sensor networks, nodes are powered by batteries with limited energy. Prolonging network lifetime is a critical issue for WSNs. As a technique for signal processing, compressed sensing (CS) is being increasingly applied to wireless sensor networks for saving energy. Compressive sensing can reduce the number of data transmissions and balance the traffic load throughout networks. In this paper, we investigate data gathering in wireless sensor networks using CS and aim at constructing a maximum-lifetime data-gathering tree. The lifetime of the network is defined as the number of data-gathering rounds until the first node depletes its energy. Based on the hybrid-CS data-gathering model, we first construct an arbitrary data-gathering tree and then use the random switching decision and optimal parent node selecting strategy to adjust the load of the bottleneck node and prolong the network lifetime. Simulation results show that the proposed algorithm outperforms several existing approaches in terms of network lifetime. Zhengyu Chen, Geng Yang, Lei Chen, and Jian Xu Copyright © 2016 Zhengyu Chen et al. All rights reserved. Distributed Channel-Aware Quantization Based on Maximum Mutual Information Thu, 26 May 2016 14:23:37 +0000 In distributed sensing systems with constrained communication capabilities, sensors’ noisy measurements must be quantized locally before transmitting to the fusion centre. When the same parameter is observed by a number of sensors, the local quantization rules must be jointly designed to optimize a global objective function. In this work we jointly design the local quantizers by maximizing the mutual information as the optimization criterion, so that the quantized measurements carry the most information about the unknown parameter. A low-complexity iterative approach is suggested for finding the local quantization rules. Using the mutual information as the design criterion, we can easily integrate the effect of communication channels in the design and consequently design channel-aware quantization rules. We observe that the optimal design depends on both the measurement and channel noises. Moreover, our algorithm can be used to design quantizers that can be deployed in different applications. We demonstrate the success of our technique through simulating estimation and detection applications, where our method achieves estimation and detection errors as low as when designing for those special purposes. Sahar Movaghati and Masoud Ardakani Copyright © 2016 Sahar Movaghati and Masoud Ardakani. All rights reserved. An Efficient Approach for Stimulating Cooperation among Nodes in Wireless Sensor Networks Thu, 26 May 2016 13:44:03 +0000 A Wireless Sensor Network (WSN), characterized as being self-organizing and multihop, consists of a large number of low-power and low-cost nodes. The cooperation among nodes is the foundation for WSNs to achieve the desired functionalities, such as the delivery or forwarding of packets. However, due to the limited resources such as energy, computational availability, and communication capabilities, there may exist some selfish nodes that refuse to cooperate with others. If the critical masses of nodes do not cooperate in the network, the network would not be able to operate to achieve its functional requirements. To resolve the problem above, we introduce a Win-Stay, Lose-Likely-Shift (WSLLS) approach into a Prisoner’s Dilemma (PD) game framework, and it applies a utility-based function, which is a linear combination of one player’s payoff and its neighbors’ in a game, to evaluate a player’s (i.e., node) performance for a game. Experimental results demonstrate that our approach performs well in stimulating cooperation in different settings under a certain condition with limited information, regardless of the static topologies types of WSNs, initial proportion of cooperation, and the average number of neighbors. Hongyun Xu, Ding Wang, Shigen Shen, Youqun Shi, and Qiying Cao Copyright © 2016 Hongyun Xu et al. All rights reserved. Improving Energy Efficiency in QoS-Constrained Wireless Sensor Networks Thu, 26 May 2016 12:58:52 +0000 Energy saving is often achieved via “squeezing” other application-sensitive Quality of Service (QoS) parameters such as delay and throughput. Accordingly, energy-saving methods must consider those QoS parameters. In this paper, we survey the most recent work on energy efficiency in WSNs and we discuss the impacts of these methods on the QoS provided. Moreover, we propose a novel divide-and-conquer procedure to deal with the trade-off between energy consumption and other QoS parameters. The idea is to tackle a certain source of energy consumption to minimize the drawn energy. Subsequently, this energy-saving method is refined to consider other service qualities. To support the correctness of our claim, three energy-saving methods, taking the QoS issues into consideration, are given as examples. The first method exploits a so-called Fuzzy transform for shrinking the wireless traffic with highly precise lossy data compression. In the second method, the sensing module is targeted by employing reliable virtual sensors. Such sensors compensate the unavailability of main energy-hungry sensors during sleep periods. The third method exploits a self-adaptive mechanism to improve the QoS parameters via deliberately reducing the lifetime below the maximum time and exploiting design-time knowledge. Mohamed Abdelaal, Oliver Theel, Christian Kuka, Peilin Zhang, Yang Gao, Vasilisa Bashlovkina, Daniela Nicklas, and Martin Fränzle Copyright © 2016 Mohamed Abdelaal et al. All rights reserved. Gateway Selection Game in Cyber-Physical Systems Thu, 26 May 2016 06:45:48 +0000 Cyber-Physical Systems (CPSs) obtain the information of the physical world and impact the environment through many different kinds of devices. Usually, devices with different wireless technologies communicate with each other and the external networks through gateways placed in the working area. Different kinds of devices in a CPS may not operate with each other for their own benefit, and the competition will be more intense between different kinds of devices. They will contend for bandwidth of gateways to increase their throughput and avoid transmission delay. In this paper, we formulate this gateway selection situation as a noncooperative game. We investigate the actions of devices when they change their gateway and the result of devices’ competition. We first give a bandwidth allocation model of gateways and propose a distributed algorithm for clients of gateway selection in order to increase the total bandwidth of their own kind. Then we investigate the migration trends of clients, and three theorems about the condition when clients stop migrating are given. We propose examples of gateway selection game with and without Nash Equilibrium. At last section, we give simulation results of gateway selection game. Hao Wang, Jianzhong Li, and Hong Gao Copyright © 2016 Hao Wang et al. All rights reserved. Message Passing Based Time Synchronization in Wireless Sensor Networks: A Survey Thu, 26 May 2016 06:00:21 +0000 Various protocols have been proposed in the area of wireless sensor networks in order to achieve network-wide time synchronization. A large number of proposed protocols in the literature employ a message passing mechanism to make sensor node clocks tick in unison. In this paper, we first classify Message Passing based Time Synchronization (MPTS) protocols and then analyze them based on different metrics. The classification is based on the following three criteria: structure formation of the network affected by the synchronization protocol, frequency of synchronization process (synchronization interval), and synchronization message overhead. Proposed protocols are analyzed and evaluated from different perspectives based on available data. A comparison table of the reviewed protocols is presented according to the evaluation metrics. Finally, some potential methods will be proposed to improve the synchronization process. Mohammad Ali Sarvghadi and Tat-Chee Wan Copyright © 2016 Mohammad Ali Sarvghadi and Tat-Chee Wan. All rights reserved. Efficient and Adaptively Secure Attribute-Based Proxy Reencryption Scheme Wed, 25 May 2016 11:21:00 +0000 Ciphertext-Policy Attribute-Based Proxy Reencryption (CP-ABPRE) has found many practical applications in the real world, because it extends the traditional Proxy Reencryption (PRE) and allows a semitrusted proxy to transform a ciphertext under an access policy to the one with the same plaintext under another access policy. The existing CP-ABPRE schemes were proven secure only in the selective security model, a limited model, which is an unnatural constraint on the attacker. The scheme proved in this model can only be called selectively secure one. However, from a security perspective, the adaptively secure CP-ABPRE scheme is more desirable. In this paper, an adaptively secure CP-ABPRE scheme is proposed, which is based on Waters’ dual system encryption technology. The proposed scheme is constructed in composite order bilinear groups and proven secure under the complexity assumptions of the subgroup decision problem for 3 primes (3P-SDP). Analyses show that our proposal provides higher computational efficiency compared with the existing schemes. Huixian Li and Liaojun Pang Copyright © 2016 Huixian Li and Liaojun Pang. All rights reserved. A Vehicular Cloud-Based Framework for the Intelligent Transport Management of Big Cities Tue, 24 May 2016 09:39:36 +0000 An intelligent transport system (ITS) is intended to streamline the operations of vehicles, manage vehicle traffic, and help drivers with safety and other information, as well as supply convenient applications for passengers. This system is essential for tackling the problems of a big city, like traffic congestion and a lack of a communication infrastructure or traffic engineering, among other factors. With these challenges in mind, we propose a vehicular cloud architecture to assist in the management of large cities. This will create a framework to support different types of services as well as provide storage mechanisms, access, and information management which includes tools for different modes of transport not only for citizens but also for commercial vehicles and emergency services like ambulances. In addition, it will be possible to increase the capacity for abstraction to meet information needs through the use of vehicular networks and the integration of VANETs with other networks, so as to provide relevant information for the monitoring and management of an intelligent transport system. Rodolfo I. Meneguette Copyright © 2016 Rodolfo I. Meneguette. All rights reserved. Online Ensemble Using Adaptive Windowing for Data Streams with Concept Drift Tue, 24 May 2016 08:39:19 +0000 Data streams, which can be considered as one of the primary sources of what is called big data, arrive continuously with high speed. The biggest challenge in data streams mining is to deal with concept drifts, during which ensemble methods are widely employed. The ensembles for handling concept drift can be categorized into two different approaches: online and block-based approaches. The primary disadvantage of the block-based ensembles lies in the difficulty of tuning the block size to provide a tradeoff between fast reactions to drifts. Motivated by this challenge, we put forward an online ensemble paradigm, which aims to combine the best elements of block-based weighting and online processing. The algorithm uses the adaptive windowing as a change detector. Once a change is detected, a new classifier is built replacing the worst one in the ensemble. By experimental evaluations on both synthetic and real-world datasets, our method performs significantly better than other ensemble approaches. Yange Sun, Zhihai Wang, Haiyang Liu, Chao Du, and Jidong Yuan Copyright © 2016 Yange Sun et al. All rights reserved. A Flexible and Scalable Architecture for Real-Time ANT+ Sensor Data Acquisition and NoSQL Storage Mon, 23 May 2016 14:10:25 +0000 Wireless Personal or Body Area Networks (WPANs or WBANs) are the main mechanisms to develop healthcare systems for an ageing society. Such systems offer monitoring, security, and caring services by measuring physiological body parameters using wearable devices. Wireless sensor networks allow inexpensive, continuous, and real-time updates of the sensor data, to the data repositories via an Internet. A great deal of research is going on with a focus on technical, managerial, economic, and social health issues. The technical obstacles, which we encounter, in general, are better methodologies, architectures, and context data storage. Sensor communication, data processing and interpretation, data interchange format, data transferal, and context data storage are sensitive phases during the whole process of body parameter acquisition until the storage. ANT+ is a proprietary (but open access) low energy protocol, which supports device interoperability by mutually agreeing upon device profile standards. We have implemented a prototype, based upon ANT+ enabled sensors for a real-time scenario. This paper presents a system architecture, with its software organization, for real-time message interpretation, event-driven based real-time bidirectional communication, and schema flexible storage. A computer user uses it to acquire and to transmit the data using a Windows service to the context server. Nadeem Qaisar Mehmood, Rosario Culmone, and Leonardo Mostarda Copyright © 2016 Nadeem Qaisar Mehmood et al. All rights reserved. Parallel Irregular Fusion Estimation Based on Nonlinear Filter for Indoor RFID Tracking System Mon, 23 May 2016 11:35:57 +0000 In practical RFID tracking systems, usually it is impossible that the readers are placed right with a “grid” structure, so effective estimation method is required to obtain the accurate trajectory. Due to the data-driven mechanism, measurement of RFID system is sampled irregularly; therefore the traditional recursive estimation may fail from to sampling point. Moreover, because the distribution density of the readers is nonuniform and multiple measurements might be implemented simultaneously, fusion of estimations also needs to be considered. In this paper, an irregular estimation strategy with parallel structure was developed, where the dynamic model update and states fusion estimation were processed synchronously to achieve real-time indoor RFID tracking. Two nonlinear estimation methods were proposed based on the extended Kalman filter (EKF) and unscented Kalman filter (UKF), respectively. The tracking performances were compared, and the simulation results show that the developed UKF method got lower covariance in indoor RFID tracking while the EKF one cost less calculating time. Xue-Bo Jin, Chao Dou, Ting-li Su, Xiao-fen Lian, and Yan Shi Copyright © 2016 Xue-Bo Jin et al. All rights reserved. Waterfalls Partial Aggregation in Wireless Sensor Networks Mon, 23 May 2016 09:13:31 +0000 In wireless sensor networks (WSNs), energy saving is a critical issue. Many research works have been undertaken to save energy. Data aggregation is one of the schemes that save energy by reducing the amount of data transmission. Normally, researchers focus on saving energy by aggregating multiple data or turning to achieving short transmission delay in data aggregation; few of them are concerned with network lifetime. This work achieves an optimum network lifetime by balancing energy consumption among nodes in network. Here, we propose a waterfalls partial aggregation, controlled by a set of waterfalls pushing rate vectors. The first contribution of this paper is to propose a waterfalls partial aggregation and to model it with queuing theory. The second contribution is that the optimum network lifetime is achieved mathematically and a near optimum algorithm is proposed for a given transmission delay. The results are compared with existing energy efficient algorithms and the evaluation results show the efficiency of proposed algorithm. Wuyungerile Li, Bing Jia, Shunsuke Saruwatari, and Takashi Watanabe Copyright © 2016 Wuyungerile Li et al. All rights reserved. MHM: A Multiple Handshaking MAC Protocol for Underwater Acoustic Sensor Networks Sun, 22 May 2016 09:30:45 +0000 Underwater acoustic sensor networks (UWASNs) are effective tools for exploring and observing the ocean. Due to the nonnegligible physical restrictions of the underwater acoustic communication, most MAC protocols applied in the existing terrestrial wireless networks become inapplicable. In this paper, we propose a multiple handshaking MAC protocol for UWASNs called multihandshaking MAC (MHM). Using the method of multiple handshaking and competitive mechanism of control packets, our protocol is proposed to make the contending nodes share the underwater acoustic channel much more fairly and more efficiently. The main idea of MHM is to allow multiple nodes to transmit and receive data packets at the same time without packet collisions. We also propose a competitive mechanism of control packets, which can guarantee that there will not be data collisions in the process of multiple packet transmissions. Simulation results show that our protocol can achieve better performance, including throughput, delay, and fairness. Wen Lin and Keyu Chen Copyright © 2016 Wen Lin and Keyu Chen. All rights reserved. Performance Analysis of M2M Sensor Networks Wed, 18 May 2016 10:24:08 +0000 The average symbol error probability (ASEP) and outage probability (OP) performance of mobile-to-mobile (M2M) senor networks employing transmit antenna selection (TAS) and selection combining (SC) over N-Nakagami fading channels are investigated in this paper. Based on the moment generating function (MGF) approach, the exact ASEP expressions are derived for several modulation schemes. The exact closed-form OP expressions are also presented. Then, the ASEP and OP performance under different conditions are evaluated through numerical simulations to confirm the accuracy of the analysis. The simulation results show that the number of antennas, the fading coefficient, and the number of cascaded components have an important influence on the ASEP and OP performance. Jingjing Wang, Lingwei Xu, Xinli Dong, Wei Shi, and Qiuna Niu Copyright © 2016 Jingjing Wang et al. All rights reserved. An Azimuth-Based Dead-End Avoiding Routing Mechanism for Providing Reliable IP Connectivity in Multihop Wireless Networks Wed, 18 May 2016 07:05:54 +0000 In a multihop wireless network, such as a wireless sensor network (WSN), with nodes being aware of their locations, the geographic routing scheme is an effective way of delivering packets to their destinations because of its 1-hop beacon broadcasting based routing related information exchange operation. The routing information obtained via 1-hop beaconing is local in the sense that it is just 1-hop compared to the multihop end-to-end routing. Hence, at some point, packets may experience no more place to be forwarded to (i.e., dead-ends). In this paper, we propose a geographical routing mechanism adopting the concept of the azimuth to reduce the possibility of packets confronting dead-ends. In other words, the node with a packet to be forwarded to the final destination figures out the next-hop node by utilizing the azimuth of the destination as a routing metric. Besides, we propose additional routing metrics for stable next-hop node selection to provide reliable IP connectivity. In order to validate the performance of the proposed routing mechanism, we evaluate its performance through the NS-2 based simulations and show that our mechanism outperforms the other schemes in terms of the packet delivery success rate, the end-to-end delay, and the number of dead-end encounters. Hyun Yu and Sanghyun Ahn Copyright © 2016 Hyun Yu and Sanghyun Ahn. All rights reserved.