Journal of Sensors The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. GAECH: Genetic Algorithm Based Energy Efficient Clustering Hierarchy in Wireless Sensor Networks Mon, 17 Aug 2015 14:10:06 +0000 Clustering the Wireless Sensor Networks (WSNs) is the major issue which determines the lifetime of the network. The parameters chosen for clustering should be appropriate to form the clusters according to the need of the applications. Some of the well-known clustering techniques in WSN are designed only to reduce overall energy consumption in the network and increase the network lifetime. These algorithms achieve increased lifetime, but at the cost of overloading individual sensor nodes. Load balancing among the nodes in the network is also equally important in achieving increased lifetime. First Node Die (FND), Half Node Die (HND), and Last Node Die (LND) are the different metrics for analysing lifetime of the network. In this paper, a new clustering algorithm, Genetic Algorithm based Energy efficient Clustering Hierarchy (GAECH) algorithm, is proposed to increase FND, HND, and LND with a novel fitness function. The fitness function in GAECH forms well-balanced clusters considering the core parameters of a cluster, which again increases both the stability period and lifetime of the network. The experimental results also clearly indicate better performance of GAECH over other algorithms in all the necessary aspects. B. Baranidharan and B. Santhi Copyright © 2015 B. Baranidharan and B. Santhi. All rights reserved. Mobile Device Based Dynamic Key Management Protocols for Wireless Sensor Networks Sun, 16 Aug 2015 13:14:16 +0000 In recent years, wireless sensor network (WSN) applications have tended to transmit data hop by hop, from sensor nodes through cluster nodes to the base station. As a result, users must collect data from the base station. This study considers two different applications: hop by hop transmission of data from cluster nodes to the base station and the direct access to cluster nodes data by mobile users via mobile devices. Due to the hardware limitations of WSNs, some low-cost operations such as symmetric cryptographic algorithms and hash functions are used to implement a dynamic key management. The session key can be updated to prevent threats of attack from each communication. With these methods, the data gathered in wireless sensor networks can be more securely communicated. Moreover, the proposed scheme is analyzed and compared with related schemes. In addition, an NS2 simulation is developed in which the experimental results show that the designed communication protocol is workable. Chin-Ling Chen, Chih-Cheng Chen, and De-Kui Li Copyright © 2015 Chin-Ling Chen et al. All rights reserved. Binding Quantum Dots to Silk Biomaterials for Optical Sensing Sun, 16 Aug 2015 13:10:03 +0000 Quantum dots (QDs), have great potential for fabricating optical sensing devices and imaging biomaterial degradation in vivo. In the present study, 2-mercaptoethylamine- (MEA-) and mercaptopropionic acid- (MPA-) capped CdTe-QDs were physically incorporated in silk films that contained a high content (>30%) of crystalline beta-sheet structure. The beta-sheets were induced by the addition of glycerol, water annealing, glycerol/annealing, or treatment with methanol. Incorporation of QDs did not influence the formation of beta-sheets. When the films were extracted with water, most QDs remained associated with the silk, based on the retention of photoluminescence in the silk films and negligible photoluminescence in the extracts. Compared to the solution state, photoluminescence intensity significantly decreased for MEA-QDs but not for MPA-QDs in the silk films, while the emission maximum blue shifted (≈4 nm) slightly for both. Further film digestion using protease XIV, alpha-chymotrypsin, and the combination of the two proteases suggested that QDs may be bound to the silk beta-sheet regions but not the amorphous regions. QDs photoluminescence in silk films was quenched when the concentration of hydrogen peroxide (H2O2) was above 0.2-0.3 mM, indicating the QDs-incorporated silk films can be used to report oxidation potential in solution. Disi Lu, Zhaozhu Zheng, Shaozhe Guo, Cheng Wang, David L. Kaplan, and Xiaoqin Wang Copyright © 2015 Disi Lu et al. All rights reserved. A Low-Power Microcontroller with Accuracy-Controlled Event-Driven Signal Processing Unit for Rare-Event Activity-Sensing IoT Devices Sun, 16 Aug 2015 13:04:27 +0000 A specially designed microcontroller with event-driven sensor data processing unit (EPU) is proposed to provide energy-efficient sensor data acquisition for Internet of Things (IoT) devices in rare-event human activity sensing applications. Rare-event sensing applications using a remotely installed IoT sensor device have a property of very long event-to-event distance, so that the inaccurate sensor data processing in a certain range of accuracy error is enough to extract appropriate events from the collected sensing data. The proposed signal-to-event converter (S2E) as a preprocessor of the conventional sensor interface extracts a set of atomic events with the specific features of interest and performs an early evaluation for the featured points of the incoming sensor signal. The conventional sensor data processing such as DSPs or software-driven algorithm to classify the meaningful event from the collected sensor data could be accomplished by the proposed event processing unit (EPU). The proposed microcontroller architecture enables an energy efficient signal processing for rare-event sensing applications. The implemented system-on-chip (SoC) including the proposed building blocks is fabricated with additional 7500 NAND gates and 1-KB SRAM tracer in 0.18 um CMOS process, consuming only 20% compared to the conventional sensor data processing method for human hand-gesture detection. Daejin Park, Jonghee M. Youn, and Jeonghun Cho Copyright © 2015 Daejin Park et al. All rights reserved. Automated Space Classification for Network Robots in Ubiquitous Environments Sun, 16 Aug 2015 12:35:45 +0000 Network robots provide services to users in smart spaces while being connected to ubiquitous instruments through wireless networks in ubiquitous environments. For more effective behavior planning of network robots, it is necessary to reduce the state space by recognizing a smart space as a set of spaces. This paper proposes a space classification algorithm based on automatic graph generation and naive Bayes classification. The proposed algorithm first filters spaces in order of priority using automatically generated graphs, thereby minimizing the number of tasks that need to be predefined by a human. The filtered spaces then induce the final space classification result using naive Bayes space classification. The results of experiments conducted using virtual agents in virtual environments indicate that the performance of the proposed algorithm is better than that of conventional naive Bayes space classification. Jiwon Choi, Seoungjae Cho, Phuong Chu, Hoang Vu, Kyhyun Um, and Kyungeun Cho Copyright © 2015 Jiwon Choi et al. All rights reserved. A Study on High Secure and Efficient MANET Routing Scheme Sun, 16 Aug 2015 12:00:56 +0000 In mobile ad hoc networks (MANETs), the more applications we use, the more security is required. In this paper, we propose a high secure and efficient routing scheme that not only satisfies the properties of anonymity, security, authentication, nonrepudiation, and unforgeability that the previous paper achieved for ad hoc networks, but also satisfies other necessary properties such as confidentiality, traceability, and flexibility for multipaths in order to make the ad hoc environment more secure and practicable. Wei-Chen Wu and Horng-Twu Liaw Copyright © 2015 Wei-Chen Wu and Horng-Twu Liaw. All rights reserved. Electrodes Modification Based on Metal-Free Phthalocyanine: Example of Electrochemical Sensors for the Detection of Acetic Acid Sun, 16 Aug 2015 07:04:35 +0000 Electroanalytical properties of tetra-tert-butyl phthalocyanine (PcH2-tBu) modified electrodes are studied by cyclic voltammetry (CV). The modified electrodes are obtained by CV deposition techniques on gold (Au) and glassy carbon (C) screen-printed electrodes (SPEs) and used for the electrochemical detection of acetic acid (AA). Based on the CV experiments, the electrodeposition mechanism is detailed. The modified PcH2-tBu electrodes reveal one oxidation and one reduction peak within the potential window of the working electrodes. In the presence of the analyte (acetic acid), the modified electrodes show sensitivity in the range of 10 mM to 400 mM. For the PcH2-tBu modified Au electrode, a limit of detection (LOD) of 5.89 mM (based on the +0.06 V peak) was obtained while for the PcH2-tBu modified C electrode a LOD of 17.76 mM (based on the +0.07 V peak) was achieved. A signal decay of 17%, based on 20 experiments, is obtained when gold is used as working electrode. If carbon is used as working electrode a value of 7% is attained. A signal decay is observed after more than 50 cycles of experiments and is more pronounced when higher concentrations of acetic acid are used. A mechanism of sensing is proposed at the end. Amadou L. Ndiaye, Alain Pauly, Sebastien Delile, Jérôme Brunet, Christelle Varenne, and Abhishek Kumar Copyright © 2015 Amadou L. Ndiaye et al. All rights reserved. Performance Improvement of Inertial Navigation System by Using Magnetometer with Vehicle Dynamic Constraints Mon, 10 Aug 2015 13:34:21 +0000 A navigation algorithm is proposed to increase the inertial navigation performance of a ground vehicle using magnetic measurements and dynamic constraints. The navigation solutions are estimated based on inertial measurements such as acceleration and angular velocity measurements. To improve the inertial navigation performance, a three-axis magnetometer is used to provide the heading angle, and nonholonomic constraints (NHCs) are introduced to increase the correlation between the velocity and the attitude equation. The NHCs provide a velocity feedback to the attitude, which makes the navigation solution more robust. Additionally, an acceleration-based roll and pitch estimation is applied to decrease the drift when the acceleration is within certain boundaries. The magnetometer and NHCs are combined with an extended Kalman filter. An experimental test was conducted to verify the proposed method, and a comprehensive analysis of the performance in terms of the position, velocity, and attitude showed that the navigation performance could be improved by using the magnetometer and NHCs. Moreover, the proposed method could improve the estimation performance for the position, velocity, and attitude without any additional hardware except an inertial sensor and magnetometer. Therefore, this method would be effective for ground vehicles, indoor navigation, mobile robots, vehicle navigation in urban canyons, or navigation in any global navigation satellite system-denied environment. Daehee Won, Jongsun Ahn, Sangkyung Sung, Moonbeom Heo, Sung-Hyuck Im, and Young Jae Lee Copyright © 2015 Daehee Won et al. All rights reserved. Correcting Air-Pressure Data Collected by MEMS Sensors in Smartphones Thu, 06 Aug 2015 11:19:55 +0000 We present a novel correction method for air-pressure data collected by microelectromechanical pressure sensors embedded in Android-based smartphones, in order to render them usable as meteorological data. The first step of the proposed correction method involves removing the mechanically derived outliers existing beyond the physical limits and those existing outside 3σ, as well as a reduction to the mean sea level pressure using the altitude data from digital elevation models. The second correction step involves classifying data by location and linear-regression analysis utilizing the temperature and humidity sensed by the smartphone to reduce correction errors by performing the analysis according to personalized settings. Air-pressure data obtained from smartphones is subject to several influential factors, depending on the users’ external environment. However, once corrected for spatial location, temperature, and humidity and for individual users after a comprehensive quality control, the corrected air-pressure data was highly reliable as an auxiliary resource for automatic weather stations. Na-Young Kim, Yong-Hyuk Kim, Yourim Yoon, Hyo-Hyuc Im, Reno K. Y. Choi, and Yong Hee Lee Copyright © 2015 Na-Young Kim et al. All rights reserved. The Binding of EGFR to GM1(3) Hosted in Lipid Raft-Like Biomembranes Insighted by Plasmonic Resonance Techniques Thu, 06 Aug 2015 09:47:50 +0000 We exploit Au/SiO2 plasmonic structures to check the effective binding activity of GM1(3) gangliosides hosted in physiological-like biomembranes, in presence of the Epidermal Growth Factor Receptor (EGFR). To this aim, we used bilayers that support the propagation of optical surface plasmon modes (plasmonic transducers, PTs) or guided modes (Plasmon Waveguide Resonators, PWRs). First, we measured the binding of EGFR to GM1(3) by using PTs. Indeed, effective interactions were evidenced, but with faint signals that prevented resolving dissociation kinetics. In order to enhance the optical responses, we turned our attention to PWRs. We first refined the design of a previously adopted Au/SiO2 PWR, finding that the nominal sensitivity is independent on SiO2 thickness but strongly dependent on its residual losses, due typically to a nonoptimal deposition process. We fabricated an improved Au/SiO2 resonator and tested the predicted signal enhancement by monitoring the binding of EGFR to GM3-enriched biomembranes. The measured signal was ~12-fold higher than that one measured using a PT, close to the maximum theoretical enhancement. The higher PWR response enabled us to detect the dissociation of EGFR from GM3, and the value of the apparent dissociation constant of the GM3-EGFR complex could be obtained. Giancarlo Margheri, Silvana Trigari, Stefano Sottini, Riccardo D’Agostino, Tommaso Del Rosso, and Mario Del Rosso Copyright © 2015 Giancarlo Margheri et al. All rights reserved. Bicriteria Optimization in Wireless Sensor Networks: Link Scheduling and Energy Consumption Tue, 04 Aug 2015 11:33:58 +0000 Link scheduling is important for reliable data communication in wireless sensor networks. Previous works mainly focus on how to find the minimum scheduling length but ignore the impact of energy consumption. In this paper, we integrate them together and solve them by multiobjective genetic algorithms. As a contribution, by jointly modeling the route selection and interference-free link scheduling problem, we give a systematical analysis on the relationship between link scheduling and energy consumption. Considering the specific many-to-one communication nature of WSNs, we propose a novel link scheduling scheme based on NSGA-II (Non-dominated Sorting Genetic Algorithm II). Our approach aims to search the optimal routing tree which satisfies the minimum scheduling length and energy consumption for wireless sensor networks. To achieve this goal, the solution representation based on the routing tree, the genetic operations including tree based recombination and mutation, and the fitness evaluation based on heuristic link scheduling algorithm are well designed. Extensive simulations demonstrate that our algorithm can quickly converge to the Pareto optimal solution between the two performance metrics. Jian Chen, Jie Jia, Enliang Dai, Yingyou Wen, and Dazhe Zhao Copyright © 2015 Jian Chen et al. All rights reserved. An Asynchronous Periodic Sequential Pattern Mining Algorithm with Multiple Minimum Item Supports for Ad Hoc Networking Tue, 04 Aug 2015 11:27:56 +0000 The original sequential pattern mining model only considers occurrence frequencies of sequential patterns, disregarding their occurrence periodicity. We propose an asynchronous periodic sequential pattern mining model to discover the sequential patterns that not only occur frequently but also appear periodically. For this mining model, we propose a pattern-growth mining algorithm to mine asynchronous periodic sequential patterns with multiple minimum item supports. This algorithm employs a divide-and-conquer strategy to mine asynchronous periodic sequential patterns in a depth-first manner recursively. We describe the process of algorithm realization and demonstrate the efficiency and stability of the algorithm through experimental results. Xiangzhan Yu, Zhaoxin Zhang, Haining Yu, Feng Jiang, and Wen Ji Copyright © 2015 Xiangzhan Yu et al. All rights reserved. Recent Advances in Security and Privacy for Wireless Sensor Networks Tue, 04 Aug 2015 11:17:04 +0000 Fei Yu, Chin-Chen Chang, Jian Shu, Iftikhar Ahmad, Jun Zhang, and Jose Maria de Fuentes Copyright © 2015 Fei Yu et al. All rights reserved. Heuristic Approach to Select Opportunistic Routing Forwarders (HASORF) to Enhance Throughput for Wireless Sensor Networks Tue, 04 Aug 2015 11:11:30 +0000 Biological schemes provide useful resources for designing adaptive routing protocols for wireless sensor networks (WSNs). The key idea behind using bioinspired routing is to find the optimal path to the destination. Similarly, the idea of opportunistic routing (OR) is to find the least number of hops to deliver the data to the destination. Numerous routing schemes have been proposed in WSNs while targeting various performance goals, such as throughput, delay, and link quality. Recently, OR schemes have come onto the scene in comparison with the traditional routing algorithms. The performance of OR schemes, however, highly depends on the selection of forwarder nodes. In this paper, we consider a chain network topology, where nodes are separated by an equal distance. The throughput of the chain network is analyzed mathematically, and based on the analysis results, a heuristic algorithm is proposed to choose the forwarder nodes. We evaluate the performance of the proposed Heuristic Approach to Select Opportunistic Routing Forwarders (HASORF) by using the ns-2 simulator and compare it with previous schemes, such as random routing, Extremely Opportunistic Routing (ExOR), and Simple Opportunistic Adaptive Routing (SOAR). The empirical results show that our proposed scheme achieves the best performance among them. Yousaf Bin Zikria, Summera Nosheen, Jin-Ghoo Choi, and Sung Won Kim Copyright © 2015 Yousaf Bin Zikria et al. All rights reserved. An ID/Locator Separation Based Group Mobility Management in Wireless Body Area Network Tue, 04 Aug 2015 11:05:49 +0000 Mobility management in wireless sensor network is the most important factor to be considered for applications such as healthcare system. Recently, Identifier (ID)/Locator (LOC) separation based mobility management scheme has been proposed for wireless sensor network. However, it does not perform well in group-based mobility management in wireless body area network, and thus it tends to induce large registration, packet delivery, and handover delays. To overcome these limitations, we propose a group-based mobility management scheme based on ID/LOC separation concept for ID-based communications with location-based routing to reduce the number of control messages. In the proposed scheme, each sensor device has a globally unique device identifier (GDID) which contains the information of its home network domain. For handover support, each access gateway maintains its home GDID register (HGR) and visiting GDID register (VGR) which are used to keep the GDID-locator (LOC) mappings for primary mobile devices in the distributed manner. Besides, in the proposed scheme, only the coordinator will send Router Solicitation and Router Advertisement messages to reduce the control messages further. By numerical analysis, we show that the proposed scheme can significantly reduce the registration, packet delivery, and handover delays, compared to the existing schemes. Moneeb Gohar, Jin-Ghoo Choi, and Seok-Joo Koh Copyright © 2015 Moneeb Gohar et al. All rights reserved. A Novel Bioinspired Multiobjective Optimization Algorithm for Designing Wireless Sensor Networks in the Internet of Things Tue, 04 Aug 2015 10:33:45 +0000 The design of wireless sensor networks (WSNs) in the Internet of Things (IoT) faces many new challenges that must be addressed through an optimization of multiple design objectives. Therefore, multiobjective optimization is an important research topic in this field. In this paper, we develop a new efficient multiobjective optimization algorithm based on the chaotic ant swarm (CAS). Unlike the ant colony optimization (ACO) algorithm, CAS takes advantage of both the chaotic behavior of a single ant and the self-organization behavior of the ant colony. We first describe the CAS and its nonlinear dynamic model and then extend it to a multiobjective optimizer. Specifically, we first adopt the concepts of “nondominated sorting” and “crowding distance” to allow the algorithm to obtain the true or near optimum. Next, we redefine the rule of “neighbor” selection for each individual (ant) to enable the algorithm to converge and to distribute the solutions evenly. Also, we collect the current best individuals within each generation and employ the “archive-based” approach to expedite the convergence of the algorithm. The numerical experiments show that the proposed algorithm outperforms two leading algorithms on most well-known test instances in terms of Generational Distance, Error Ratio, and Spacing. Jun Huang, Liqian Xu, Cong-cong Xing, and Qiang Duan Copyright © 2015 Jun Huang et al. All rights reserved. A Self-Adaptive Wireless Sensor Network Coverage Method for Intrusion Tolerance Based on Trust Value Mon, 03 Aug 2015 13:19:40 +0000 The sensor is quite easily attacked or invaded during the process of the node coverage optimization. It is a great challenge to make sure that the wireless sensor network could still carry out a secure communication and reliable coverage under the condition of being attacked. Therefore, this paper proposes a network coverage method for intrusion tolerance based on trust value of nodes by combining the trust value model with the reliable coverage optimization. It first estimates trust value of nodes through which to regulate the perception radius and decision-making radius. Furthermore, this algorithm also combines the classical methods of wireless network coverage, such as GSO and PSO, to realize the networks coverage of invasive tolerant sensor. After comparing with the conventional single cover mechanism, it can improve the security and coverage rate of network under the condition of invasion. The simulation results verify the effectiveness of the algorithm. Zuo Chen, Xue Li, Bing Yang, and Qian Zhang Copyright © 2015 Zuo Chen et al. All rights reserved. Survey of Security Technologies on Wireless Sensor Networks Mon, 03 Aug 2015 12:13:20 +0000 Because of their low cost and adaptability, wireless sensor networks are widely used in civil, military, and commercial fields and other fields. However, since the sensor node in the calculation of the capacity, battery capacity, and storage capacity are restricted by the limitations and inherent characteristics of the sensor networks, compared to traditional networks, which makes wireless sensor networks face more security threats. This paper summarized research progress of sensor network security issues as three aspects, key management, authentication, and secure routing, analyzed and commented on these results advantages and disadvantages and pointed out the future direction of the hot research field. Qiuwei Yang, Xiaogang Zhu, Hongjuan Fu, and Xiqiang Che Copyright © 2015 Qiuwei Yang et al. All rights reserved. Accurately Identifying New QoS Violation Driven by High-Distributed Low-Rate Denial of Service Attacks Based on Multiple Observed Features Mon, 03 Aug 2015 12:09:44 +0000 We propose using multiple observed features of network traffic to identify new high-distributed low-rate quality of services (QoS) violation so that detection accuracy may be further improved. For the multiple observed features, we choose F feature in TCP packet header as a microscopic feature and, P feature and D feature of network traffic as macroscopic features. Based on these features, we establish multistream fused hidden Markov model (MF-HMM) to detect stealthy low-rate denial of service (LDoS) attacks hidden in legitimate network background traffic. In addition, the threshold value is dynamically adjusted by using Kaufman algorithm. Our experiments show that the additive effect of combining multiple features effectively reduces the false-positive rate. The average detection rate of MF-HMM results in a significant 23.39% and 44.64% improvement over typical power spectrum density (PSD) algorithm and nonparametric cumulative sum (CUSUM) algorithm. Jian Kang, Mei Yang, and Junyao Zhang Copyright © 2015 Jian Kang et al. All rights reserved. A Review on Sensor Network Issues and Robotics Mon, 03 Aug 2015 06:40:39 +0000 The interaction of distributed robotics and wireless sensor networks has led to the creation of mobile sensor networks. There has been an increasing interest in building mobile sensor networks and they are the favored class of WSNs in which mobility plays a key role in the execution of an application. More and more researches focus on development of mobile wireless sensor networks (MWSNs) due to its favorable advantages and applications. In WSNs robotics can play a crucial role, and integrating static nodes with mobile robots enhances the capabilities of both types of devices and enables new applications. In this paper we present an overview on mobile sensor networks in robotics and vice versa and robotic sensor network applications. Ji Hyoung Ryu, Muhammad Irfan, and Aamir Reyaz Copyright © 2015 Ji Hyoung Ryu et al. All rights reserved. Research on Handoff Delay and Mobility Management Cost of Mobility Protocols in Wireless Sensor Networks Mon, 03 Aug 2015 06:38:56 +0000 An appropriate network model and some suitable performance evaluation criterions including handoff delay and mobility management cost were proposed in this paper. And in this base the performance of Mobile IP protocol and various micromobility protocols was comprehensively compared and investigated. The research results show that the performance is mainly influenced by two factors which are route update methods of mobility support protocols and mobile network parameters. The route update time and mobility management cost of micromobility protocol are obviously shorter than that of Mobile IP. In all researched micromobility protocols, the route update method of Mobile IP Regional Registration protocol has the optimal performance. A. Q. Zhao and Y. Hu Copyright © 2015 A. Q. Zhao and Y. Hu. All rights reserved. Trust-Aware and Low Energy Consumption Security Topology Protocol of Wireless Sensor Network Mon, 03 Aug 2015 06:35:20 +0000 Wireless sensor network (WSN) is a kind of distributed and self-organizing networks, in which the sensor nodes have limited communication bandwidth, memory, and limited energy. The topology construction of this network is usually vulnerable when attacked by malicious nodes. Besides, excessive energy consumption is a problem that can not be ignored. Therefore, this paper proposes a secure topology protocol of WSN which is trust-aware and of low energy consumption, called TLES. The TLES considers the trust value as an important factor affecting the behavior of node. In detail, the TLES would take trust value, residual energy of the nodes, and node density into consideration when selecting cluster head nodes. Then, TLES constructs these cluster head nodes by choosing the next hop node according to distance to base station (BS), nodes’ degrees, and residual energy, so as to establish a safe, reliable, and energy saving network. Experimental results show that the algorithm can effectively isolate the malicious node in the network and reduce the consumption of energy of the whole network. Zuo Chen, Min He, Wei Liang, and Kai Chen Copyright © 2015 Zuo Chen et al. All rights reserved. Sequence Alignment with Dynamic Divisor Generation for Keystroke Dynamics Based User Authentication Sun, 02 Aug 2015 13:47:36 +0000 Keystroke dynamics based authentication is one of the prevention mechanisms used to protect one’s account from criminals’ illegal access. In this authentication mechanism, keystroke dynamics are used to capture patterns in a user typing behavior. Sequence alignment is shown to be one of effective algorithms for keystroke dynamics based authentication, by comparing the sequences of keystroke data to detect imposter’s anomalous sequences. In previous research, static divisor has been used for sequence generation from the keystroke data, which is a number used to divide a time difference of keystroke data into an equal-length subinterval. After the division, the subintervals are mapped to alphabet letters to form sequences. One major drawback of this static divisor is that the amount of data for this subinterval generation is often insufficient, which leads to premature termination of subinterval generation and consequently causes inaccurate sequence alignment. To alleviate this problem, we introduce sequence alignment of dynamic divisor (SADD) in this paper. In SADD, we use mean of Horner’s rule technique to generate dynamic divisors and apply them to produce the subintervals with different length. The comparative experimental results with SADD and other existing algorithms indicate that SADD is usually comparable to and often outperforms other existing algorithms. Jiacang Ho and Dae-Ki Kang Copyright © 2015 Jiacang Ho and Dae-Ki Kang. All rights reserved. Distributed Software-Attestation Defense against Sensor Worm Propagation Sun, 02 Aug 2015 13:46:52 +0000 Wireless sensor networks are vulnerable to sensor worm attacks in which the attacker compromises a few nodes and makes these compromised nodes initiate worm spread over the network, targeting the worm infection of the whole nodes in the network. Several defense mechanisms have been proposed to prevent worm propagation in wireless sensor networks. Although these proposed schemes use software diversity technique for worm propagation prevention under the belief that different software versions do not have common vulnerability, they have fundamental drawback in which it is difficult to realize the aforementioned belief in sensor motes. To resolve this problem, we propose on-demand software-attestation based scheme to defend against worm propagation in sensor network. The main idea of our proposed scheme is to perform software attestations against sensor nodes in on-demand manner and detect the infected nodes by worm, resulting in worm propagation block in the network. Through analysis, we show that our proposed scheme defends against worm propagation in efficient and robust manner. Through simulation, we demonstrate that our proposed scheme stops worm propagation at the reasonable overhead while preventing a majority of sensor nodes from being infected by worm. Jun-Won Ho Copyright © 2015 Jun-Won Ho. All rights reserved. B-iTRS: A Bio-Inspired Trusted Routing Scheme for Wireless Sensor Networks Sun, 02 Aug 2015 13:44:47 +0000 In WSNs, routing algorithms need to handle dynamical changes of network topology, extra overhead, energy saving, and other requirements. Therefore, routing in WSNs is an extremely interesting and challenging issue. In this paper, we present a novel bio-inspired trusted routing scheme (B-iTRS) based on ant colony optimization (ACO) and Physarum autonomic optimization (PAO). For trust assessment, B-iTRS monitors neighbors’ behavior in real time, receives feedback from Sink, and then assesses neighbors’ trusts based on the acquired information. For routing scheme, each node finds routes to the Sink based on ACO and PAO. In the process of path finding, B-iTRS senses the load and trust value of each node and then calculates the link load and link trust of the found routes to support the route selection. Moreover, B-iTRS also assesses the route based on PAO to maintain the route table. Simulation results show how B-iTRS can achieve the effective performance compared to existing state-of-the-art algorithms. Mingchuan Zhang, Ruijuan Zheng, Qingtao Wu, Wangyang Wei, Xiuling Bai, and Haixia Zhao Copyright © 2015 Mingchuan Zhang et al. All rights reserved. A Novel Digital Certificate Based Remote Data Access Control Scheme in WSN Sun, 02 Aug 2015 13:42:10 +0000 A digital certificate based remote data access control scheme is proposed for safe authentication of accessor in wireless sensor network (WSN). The scheme is founded on the access control scheme on the basis of characteristic expression (named CEB scheme). Data is divided by characteristics and the key for encryption is related to characteristic expression. Only the key matching with characteristic expression can decrypt the data. Meanwhile, three distributed certificate detection methods are designed to prevent the certificate from being misappropriated by hostile anonymous users. When a user starts query, the key access control method can judge whether the query is valid. In this case, the scheme can achieve public certificate of users and effectively protect query privacy as well. The security analysis and experiments show that the proposed scheme is superior in communication overhead, storage overhead, and detection probability. Wei Liang, Zhiqiang Ruan, Hongbo Zhou, and Yong Xie Copyright © 2015 Wei Liang et al. All rights reserved. Parking Query in Vehicular Delay-Tolerant Networks with Privacy Protection Based on Secure Multiparty Computation Sun, 02 Aug 2015 12:59:38 +0000 Within vehicular delay-tolerant network, conflict exists in the scenario of which two vehicles happen to choose the same parking space. To solve this problem, two protocols are proposed, respectively, which are called privacy protection protocol based on secure multiparty computation and routing protocol based on angle and density. The proposed methods prevent the leaking of privacy information of the vehicles involved during the parking space seeking process and improve the performance of the transmission ratio and reduce the transmission delay by unifying the directions of messages and choosing the vehicle of the highest distribution density as the next hop. The results of the simulation show the efficiency of our method. Haiping Huang, Juan Feng, Dan Sha, Jia Xu, and Hua Dai Copyright © 2015 Haiping Huang et al. All rights reserved. Sensor Networks Hierarchical Optimization Model for Security Monitoring in High-Speed Railway Transport Hub Sun, 02 Aug 2015 12:39:50 +0000 We consider the sensor networks hierarchical optimization problem in high-speed railway transport hub (HRTH). The sensor networks are optimized from three hierarchies which are key area sensors optimization, passenger line sensors optimization, and whole area sensors optimization. Case study on a specific HRTH in China showed that the hierarchical optimization method is effective to optimize the sensor networks for security monitoring in HRTH. Zhengyu Xie and Yong Qin Copyright © 2015 Zhengyu Xie and Yong Qin. All rights reserved. Intrusion Detection Algorithm for Mitigating Sinkhole Attack on LEACH Protocol in Wireless Sensor Networks Sun, 02 Aug 2015 12:38:43 +0000 In wireless sensor network (WSN), the sensors are deployed and placed uniformly to transmit the sensed data to a centralized station periodically. So, the major threat of the WSN network layer is sinkhole attack and it is still being a challenging issue on the sensor networks, where the malicious node attracts the packets from the other normal sensor nodes and drops the packets. Thus, this paper proposes an Intrusion Detection System (IDS) mechanism to detect the intruder in the network which uses Low Energy Adaptive Clustering Hierarchy (LEACH) protocol for its routing operation. In the proposed algorithm, the detection metrics, such as number of packets transmitted and received, are used to compute the intrusion ratio (IR) by the IDS agent. The computed numeric or nonnumeric value represents the normal or malicious activity. As and when the sinkhole attack is captured, the IDS agent alerts the network to stop the data transmission. Thus, it can be a resilient to the vulnerable attack of sinkhole. Above all, the simulation result is shown for the proposed algorithm which is proven to be efficient compared with the existing work, namely, MS-LEACH, in terms of minimum computational complexity and low energy consumption. Moreover, the algorithm was numerically analyzed using TETCOS NETSIM. Ranjeeth Kumar Sundararajan and Umamakeswari Arumugam Copyright © 2015 Ranjeeth Kumar Sundararajan and Umamakeswari Arumugam. All rights reserved. A Data Processing Middleware Based on SOA for the Internet of Things Sun, 02 Aug 2015 12:37:48 +0000 The Internet of Things (IoT) emphasizes on connecting every object around us by leveraging a variety of wireless communication technologies. Heterogeneous data fusion is widely considered to be a promising and urgent challenge in the data processing of the IoT. In this study, we first discuss the development of the concept of the IoT and give a detailed description of the architecture of the IoT. And then we design a middleware platform based on service-oriented architecture (SOA) for integration of multisource heterogeneous information. New research angle regarding flexible heterogeneous information fusion architecture for the IoT is the theme of this paper. Experiments using environmental monitoring sensor data derived from indoor environment are performed for system validation. Through the theoretical analysis and experimental verification, the data processing middleware architecture represents better adaptation to multisensor and multistream application scenarios in the IoT, which improves heterogeneous data utilization value. The data processing middleware based on SOA for the IoT establishes a solid foundation of integration and interaction for diverse networks data among heterogeneous systems in the future, which simplifies the complexity of integration process and improves reusability of components in the system. Feng Wang, Liang Hu, Jin Zhou, and Kuo Zhao Copyright © 2015 Feng Wang et al. All rights reserved.