http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2013 , Hindawi Publishing Corporation . All rights reserved. Tue, 18 Jun 2013 16:00:57 +0000 http://www.hindawi.com/journals/ijdsn/2013/936816/ The rapid adoption of wireless communication and sensors technology has raised the awareness of many laboratories about the field of network embedded system. Most researchers aim to exploit these advances to enable technological assistance of frail persons in smart homes. However, to reach the full potential of applications using network embedded systems such as assistive smart home, scientists need to work toward the creation of support services. In this paper, we present an accurate passive RFID localization technique, which can easily be implemented and deployed in various environments, coupled to a complete human activity recognition model. The goal of this paper is to demonstrate, through concrete experiments, that support services can enable powerful solution to long-lived challenges of the network embedded system community. Particularly, the model exploits qualitative spatial reasoning from RFID localization of objects in the smart home to learn and recognize the basic and instrumental activities of daily living of a resident. Our system was deployed in a real smart home, and the results obtained were quite encouraging. The developed RFID technique gives an average precision of ±14.12 cm, and the recognition algorithm recognizes up to 92% activities. Kevin Bouchard, Dany Fortin-Simard, Sebastien Gaboury, Bruno Bouchard, and Abdenour Bouzouane Copyright © 2013 Kevin Bouchard et al. All rights reserved. Tue, 18 Jun 2013 15:39:30 +0000 http://www.hindawi.com/journals/ijdsn/2013/520507/ Recently, as the information industry and mobile communication technology develop, their study is conducted on the new concept of intelligent structures and maintenance techniques that apply wireless sensor network, USN (Ubiquitous Sensor Network), to social infrastructures such as civil and architectural structures on the basis of the concept of Ubiquitous Computing, which invisibly provides human life with computing, along with mutually cooperating, compromising, and connecting networks to each other by having computers within all objects around us. The purpose of this study is to investigate the capability of wireless communication of sensor node embedded in reinforced concrete structure with a basic experiment on electric wave permeability of sensor node by fabricating molding with variables of concrete thickness and steel bars that are mostly used in constructing structures to determine the feasibility of application to constructing structures with USN. By installing wireless communication module inside the structures, it is possible to communicate to measure the pitch of steel bars and permeability of concrete, by measuring in both directions horizontally and vertically. The magnitude of an electric wave in the range of used frequencies was measured by using Spectrum Analyzer. This electric wave was numerically analyzed and the effective wavelength of frequencies was analyzed by the properties of a frequency band area. As a result of constructing structures with wireless sensors, Plain concrete showed 45 cm for depth of permeability. Reinforced concretes that has pitches of 5 cm showed 37 cm and pitches of 15 cm showed 45 cm for the depth of permeability. This suggests that if the pitch of steel bars was more than 15 cm, it would not affect wireless communication. Byung-Wan Jo, Jung-Hoon Park, and Kwang-Won Yoon Copyright © 2013 Byung-Wan Jo et al. All rights reserved. Tue, 18 Jun 2013 15:00:31 +0000 http://www.hindawi.com/journals/ijdsn/2013/834547/ This paper presents the security evaluation, energy consumption optimization, and spectrum scarcity analysis of artificial noise techniques to increase physical-layer security in Cognitive Wireless Sensor Networks (CWSNs). These techniques introduce noise into the spectrum in order to hide real information. Nevertheless, they directly affect two important parameters in Cognitive Wireless Sensor Networks (CWSNs), energy consumption and spectrum utilization. Both are affected because the number of packets transmitted by the network and the active period of the nodes increase. Security evaluation demonstrates that these techniques are effective against eavesdropper attacks, but also optimization allows for the implementation of these approaches in low-resource networks such as Cognitive Wireless Sensor Networks. In this work, the scenario is formally modeled and the optimization according to the simulation results and the impact analysis over the frequency spectrum are presented. Javier Blesa, Alvaro Araujo, Elena Romero, and Octavio Nieto-Taladriz Copyright © 2013 Javier Blesa et al. All rights reserved. Tue, 18 Jun 2013 14:50:17 +0000 http://www.hindawi.com/journals/ijdsn/2013/692735/ This paper proposes a 6LoWPAN service model based on the IPv6-based -Anycast communication model. This model is extended into 6LoWPAN service model so that the data-centric services of WSN can be achieved efficiently in the address-centric 6LoWPAN. In the proposed service model, an IPv6 node can obtain multiple network services through one request-response interaction where multiple sensor nodes cooperate to complete all requested network services and they provide their respective network services at the same time. As a result, the delay time is shortened. In addition, the proposed service model avoids the service failure caused by dormant sensor nodes. Since users can only request the network services they are interested in, the redundant data transmission is avoided. The performance parameters of the proposed service model are analyzed, and the data results show that the performance of the proposed service model is better. Xiaonan Wang and Haili Huang Copyright © 2013 Xiaonan Wang and Haili Huang. All rights reserved. Tue, 18 Jun 2013 14:47:02 +0000 http://www.hindawi.com/journals/ijdsn/2013/397926/ Key management in a large portion of ubiquitous sensor networks has been a challenge due to the limited capabilities of their wireless communicating and battery-powered sensors. Moreover, an attacker physically capturing even a few nodes hampers the entire network security by impersonating nodes to inject false data in an undetected manner. To efficiently protect from such impersonating by node capture, we propose a new dynamic key management framework particularly for large-scale clustered sensor networks. In the framework, different keying mechanisms, respectively, secure in-cluster, intercluster, and individual communication by refreshing keys on demand, while adaptively handling node addition and capture. Theoretic analysis and simulation results show that our proposed framework provides higher connectivity and security against impersonating than other existing studies do, for better trade-off with resource overheads. Gowun Jeong, Yong-Ho Seo, and Hyun S. Yang Copyright © 2013 Gowun Jeong et al. All rights reserved. Sun, 16 Jun 2013 12:10:22 +0000 http://www.hindawi.com/journals/ijdsn/2013/737680/ More accurate predictions of energy consumption are a strong motivator for utility providers to deploy a smart grid infrastructure. However, measurements which only reflect the consumption of a household lose the details associated with the behaviour of individual devices. Finding a flexible and efficient way to process these readings is essential. Using standard application techniques to integrate device-oriented sensor networks and data-oriented applications is a serious challenge due to the architectural gap between the different approaches. Additionally, this device-level information should be shared with the end-users in a trusted manner to increase their energy awareness. We propose a novel platform for the smart grid which enables the seamless integration of sensor networks with a service-oriented architecture approach. The platform hides the device-specific details from the applications and transforms data into a device-independent format. Specifically, we present an in-depth description of the architecture of our platform and a full implementation and evaluation of it in a live residential energy management deployment. C. Busemann, V. Gazis, R. Gold, P. Kikiras, A. Leonardi, J. Mirkovic, M. Walther, and H. Ziekow Copyright © 2013 C. Busemann et al. All rights reserved. Sun, 16 Jun 2013 12:01:41 +0000 http://www.hindawi.com/journals/ijdsn/2013/391986/ In wireless sensor networks (WSNs), hierarchical routing protocol is commonly used for energy efficiency. In particular, the TEEN (Threshold sensitive Energy Efficient sensor Network) protocol is used widely as a basic clustered multihop routing protocol. However, energy efficient routing protocols without proper security suffer from many security vulnerabilities. Hence, in this paper, we propose a hybrid key scheme specially for the TEEN protocol: a symmetric key scheme for the intracluster and a public key scheme for the intercluster. The simulation results show that network lifetime of the proposed hybrid key scheme decreases about 8% than the TEEN protocol and about 4% compared with the TEEN protocol with symmetric key scheme. On the other hand, a hybrid key scheme provides better probability of successful transmission than that of the symmetric key scheme. Saewoom Lee, Youngtae Noh, and Kiseon Kim Copyright © 2013 Saewoom Lee et al. All rights reserved. Sat, 15 Jun 2013 17:27:14 +0000 http://www.hindawi.com/journals/ijdsn/2013/852090/ This work presents an offshore pipeline scour monitoring sensor network system based on active thermometry. The system consists of thermal cables, data acquisition unit, and data processing unit. As the thermal cables emit heats, the distributed DS18B20 digital temperature sensors record temperature information over time. The scour-induced exposure and free spanning can be identified by analyzing the temperature curves. Pipeline exposure and free-spanning experiments were carried out in laboratory, whose results show that the system is able to give overall information about the development of pipeline scour. Difference values analysis reveals the changing patterns of heat transfer behavior for line heat source in sediment and water scenarios. Two features, magnitude and temporal instability, are extracted from temperature curves to better differentiate sediment and water scenarios. Based on these two features, K-means clustering algorithm is adopted for pattern classification of the system, which was implemented in MATLAB and facilitated the automatic detection of the scour monitoring sensor network system. The proposed sensor network has the advantages of low cost, high precision and construction flexiblility, providing a promising approach for offshore pipeline scour monitoring, especially suitable for nearshore environment. Xuefeng Zhao, Weijie Li, Lei Zhou, Gang-Bing Song, Qin Ba, and Jinping Ou Copyright © 2013 Xuefeng Zhao et al. All rights reserved. Thu, 13 Jun 2013 14:50:25 +0000 http://www.hindawi.com/journals/ijdsn/2013/240230/ Wireless sensor networks are susceptible to node replication attacks due to their unattended nature. Existing replicas detection schemes can be further improved in regard of detection probabilities, detection overheads, and the balance of detection overheads among sensor nodes. In this paper, we make the following contributions: first, we point out the unrealistic assumption that the replica node would behave honestly as the benign sensor nodes; thus the existing detection schemes would fail if the replica nodes cheat or collude with the compromised node. Then, we propose a location-binding symmetric key scheme forcing the replica nodes to be inserted only in the vicinity of the compromised node. Later, a detecting scheme is presented to inspect the location claims within the neighborhood. Finally, analysis shows that our scheme helps to detect and defend against replication attacks effectively and efficiently. Extensive simulations are conducted and the results show that the detection overheads are low and evenly distributed among all the sensor nodes. Xiang-yi Chen, Li-xia Meng, and Yong-zhao Zhan Copyright © 2013 Xiang-yi Chen et al. All rights reserved. Wed, 12 Jun 2013 15:10:24 +0000 http://www.hindawi.com/journals/ijdsn/2013/245017/ In order to realize a methodical, effective cooperative stimulation for MANETs and search dynamic trust cooperative stimulation scheme in environment under a high malicious ratio, we have proposed an evolutionary game-based trust cooperative stimulation model for large scale MANETs in this paper. First, the system members' pluralistic behavior for MANETs has been covered by means of constructing the complete multirisk level strategy space. Then a trust-preferential strategy has been built through trust numerical value mapping technology, which achieves the aim that the malicious action is effectively constrained to avoid a low trust level. Furthermore, the mobility probable parameters and information propagation error matrix are introduced into game model, and the convergence condition between optimum strategy which represents payoff maximization principle and trust-preferential strategy is deduced through evolutionary analyzing finally. Both theoretical analysis and simulation experiments have demonstrated that our model can effectively stimulate cooperation among members and meanwhile be robust under the condition where the environment is harsh under a high original malicious ratio in large scale MANETs. Xiao Wang, Yinfeng Wu, Yongji Ren, Renjian Feng, Ning Yu, and Jiangwen Wan Copyright © 2013 Xiao Wang et al. All rights reserved. Wed, 12 Jun 2013 13:52:40 +0000 http://www.hindawi.com/journals/ijdsn/2013/217876/ Data aggregation techniques have been proposed for wireless sensor networks (WSNs) to address the problems presented by the limited resources of sensor nodes. The provision of efficient data aggregation to preserve data privacy is a challenging issue in WSNs. Some existing data aggregation methods for preserving data privacy are CPDA, SMART, the Twin-Key based method, and GP2S. These methods, however, have two limitations. First, the communication cost for network construction is considerably high. Second, they do not support data integrity. There are two methods for supporting data integrity, iCPDA and iPDA. But they have high communication cost due to additional integrity checking messages. To resolve this problem, we propose a novel Hilbert-curve based data aggregation scheme that enforces data privacy and data integrity for WSNs. To minimize communication cost, we utilize a tree-based network structure for constructing networks and aggregating data. To preserve data privacy, we make use of both a seed exchange algorithm and Hilbert-curve based data encryption. To support data integrity, we use an integrity checking algorithm based on the PIR technique by directly communicating between parent and child nodes. Finally, through a performance analysis, we show that our scheme outperforms the existing methods in terms of both energy efficiency and privacy preservation. Yong-Ki Kim, Hyunjo Lee, Min Yoon, and Jae-Woo Chang Copyright © 2013 Yong-Ki Kim et al. All rights reserved. Mon, 10 Jun 2013 17:49:02 +0000 http://www.hindawi.com/journals/ijdsn/2013/120527/ In wireless networks, wireless sniffers are distributed in a region to monitor the activities of users. It can be applied for fault diagnosis, resource management, and critical path analysis. Due to hardware limitations, wireless sniffers typically can only collect information on one channel at a time. Therefore, it is a key topic to optimize the channel selection for sniffers to maximize the information collected, so as to maximize the Quality of Monitoring (QoM) for wireless networks. In this paper, a Multiple-Quantum-Immune-Clone-Algorithm- (MQICA-) based solution was proposed to achieve the optimal channel allocation. The extensive simulations demonstrate that MQICA outperforms the related algorithms evidently with higher monitoring quality, lower computation complexity, and faster convergence. The practical experiment also shows the feasibility of this algorithm. Na Xia, Lina Xu, and Chengchun Ni Copyright © 2013 Na Xia et al. All rights reserved. Mon, 10 Jun 2013 09:38:24 +0000 http://www.hindawi.com/journals/ijdsn/2013/589750/ Yingtao Jiang, Lei Zhang, and Ling Wang Copyright © 2013 Yingtao Jiang et al. All rights reserved. Sun, 09 Jun 2013 18:31:35 +0000 http://www.hindawi.com/journals/ijdsn/2013/358120/ Message delivery in a mobile social network (MSN) is difficult due to the fact that the topology of such network is sparse and unstable. Various routing schemes for MSNs were proposed to make the message delivery robust and efficient. However, little research has been conducted to explore how much delay has to be tolerated for the message delivery from the source to the destination. Since the social relationships among nodes are stable during a certain period of time, it is expected that the delay of message delivery in MSNs could be modeled with a probability model. In this paper, we take the first step to address this issue. We firstly extract three routing models from the existing routing schemes for MSNs and then develop the probability models of the message transmission delay for each abstract routing model. The simulation results show that the theoretical models match very well the simulation trace statistics. Yanqin Zhu, Haojun Zhang, and Qijin Ji Copyright © 2013 Yanqin Zhu et al. All rights reserved. Sun, 09 Jun 2013 15:10:34 +0000 http://www.hindawi.com/journals/ijdsn/2013/102508/ Wireless Sensor Network (WSN) has proved its presence in various real time applications and hence the security of such embedded devices is a vital issue. Certificateless cryptography is one of the recent paradigms to provide security. Certificateless public key cryptography (CL-PKC) deals effectively with the twin issues of certificate management in traditional public key cryptography and key escrow problem in identity-based cryptography. CL-PKC has attracted special attention in the field of information security as it has opened new avenues for improvement in the present security architecture. Recently, Tsai et al. proposed an improved certificateless signature scheme without pairing and claimed that their new construction is secure against different kinds of attacks. In this paper, we present a security analysis of their scheme and our results show that scheme does not have resistance against malicious-KGC attack. In addition, we have found some security flaws in the certificateless signature scheme of Fan et al. and proved the scheme vulnerable to Strong Type I attack. Gaurav Sharma, Suman Bala, and Anil K. Verma Copyright © 2013 Gaurav Sharma et al. All rights reserved. Sun, 09 Jun 2013 11:00:32 +0000 http://www.hindawi.com/journals/ijdsn/2013/784618/ EPCglobal network is used to share product data between trading partners, which was proposed by EPCglobal. Object Name Service (ONS) in EPCglobal framework raises two critical security risks: the authenticity of IP addresses for Physical Markup Language (PML) servers and the privacy of Electronic Product Codes (EPCs). Existing work considers either the IP address authentication or the EPC privacy. In addition, that work mainly relies on cryptographic tools, in which key distribution is not a trivial task and also causes a large amount of computation overhead. In this paper, we make the first attempt to solve those two security risks together without relying cryptography. We propose a scheme, namely, APP (authenticate ONS and protect EPC privacy), to guarantee the authenticity of IP addresses for PML servers as well as EPC privacy and to maintain ultralightweight computation cost. Moreover, we give formal definition of the authenticity and the privacy in ONS context. The security achievements are strictly analyzed and proved. The extensive analysis results justify the applicability of the proposed scheme. Wei Ren, Liangli Ma, and Yi Ren Copyright © 2013 Wei Ren et al. All rights reserved. Thu, 06 Jun 2013 14:17:53 +0000 http://www.hindawi.com/journals/ijdsn/2013/406061/ Wireless sensor networks (WSNs) are subject to various attacks because of the vulnerable environment, limited recourse, and open communication channel. To protect WSNs, in this paper, we present a Secret sharing-based key management (SSKM). SSKM utilizes the advantages of hierarchical architecture and adopts two-level key management and authentication mechanism, which can efficiently protect the allover network communication security and survivability. Different from previous works, the SSKM distributes keys based on secret sharing mechanism by the clustered architecture, which not only localizes the key things but also keeps scalability. The SSKM provides various session keys, the network key for base station (BS) and cluster heads (CHs); the cluster key between the cluster head and member nodes. The SSKM dynamically generates different keys based on different polynomials from BS in different periods which can protect the network from the compromised nodes and reduce the high probability of the common keys. The security analysis shows that the SSKM can prevent several attacks effectively and reduce the energy consumption. Yiying Zhang, Chunying Wu, Jinping Cao, and Xiangzhen Li Copyright © 2013 Yiying Zhang et al. All rights reserved. Thu, 06 Jun 2013 09:37:53 +0000 http://www.hindawi.com/journals/ijdsn/2013/912873/ Body area network (BAN) is an emerging branch of wireless sensor networks for personalized applications in many fields, such as health monitoring. The services in BAN usually have a high requirement on security, especially for the medical diagnosis, which involves private information. With limitations of power and computation capabilities, one of the main challenges to ensure security in BAN is how to generate or distribute a shared key between nodes for lightweight symmetric cryptography. The current research almost exploits the randomness and distinctiveness (characteristics) of physiological signals to solve the key generation problem. However, it needs the help of additional hardware support and has the constraint on positions deployment, to acquire vital signals, which will bring the high cost and hardness to implementation of real system. To avoid the above problems, this paper presents a novel key generation scheme and a key distribution protocol, both of which are only based on wireless modules equipped on sensors. By exploiting the high correlation of received signal strength index (RSSI) between peer-to-peer communications, our scheme can provide a shared symmetric cryptographic key under the presence of an eavesdropper. We conduct experiments on the real Telosb nodes, and the results demonstrate that our proposed methods have a good performance on security. Yang Wu, Yongmei Sun, Lei Zhan, and Yuefeng Ji Copyright © 2013 Yang Wu et al. All rights reserved. Wed, 05 Jun 2013 15:08:00 +0000 http://www.hindawi.com/journals/ijdsn/2013/942347/ Automated Planning has been successfully used in many domains like robotics or transportation logistics. However, building an action model is a difficult and time-consuming task even for domain experts. This paper presents a system, ASRA-AMLA, for automatically generating planning action models from sensor readings. Activity recognition is used to extract the actions that a user performs and the states produced by those actions. Then, the sequences of actions and states are used to infer a planning action model. With this approach, the system can automatically build an action model related to human-centered activities. It allows us to automatically build an assistance system for guiding humans to complete a task using Automated Planning. To test our approach, a new dataset from a kitchen domain has been generated. The tests performed show that our system is capable of extracting actions and states correctly from sensor time series and creating a planning domain used to guide a human to complete a task correctly. Javier Ortiz, Angel García-Olaya, and Daniel Borrajo Copyright © 2013 Javier Ortiz et al. All rights reserved. Wed, 05 Jun 2013 09:27:06 +0000 http://www.hindawi.com/journals/ijdsn/2013/249598/ Water quality refers to the physical, chemical, and biological characteristics of water, and it is a measure of the condition of water relative to any human need or purpose. A particular problem with measuring the condition of water quality at drinking water reservoirs is the requirement of collecting a large number of samples. To handle this problem, we focus on the practical use of two different portable and low-cost approaches for continuous monitoring of water quality: miniboats loaded with sondes with probes and wireless sensor network- (WSN-) based monitoring system. These approaches bring several advantages over traditional monitoring systems in terms of cost, portability, and applicability. Our simulation studies show that these systems can be used to monitor water quality at drinking water reservoirs such as dams and holding ponds. Field tests to prove the effectiveness of the proposed systems are in progress. Gurkan Tuna, Orhan Arkoc, and Kayhan Gulez Copyright © 2013 Gurkan Tuna et al. All rights reserved. Wed, 05 Jun 2013 09:26:57 +0000 http://www.hindawi.com/journals/ijdsn/2013/328747/ Traditionally, Wireless Sensor Networks (WSNs) are used for monitoring an extensive area. In these networks, a centralized server is usually used to collect and store the sensor information. However, new distributed protocols allow connections directly to the WSN nodes without the need of a centralized server. Moreover, these systems are able to establish communications among heterogeneous networks. The new protocols strategy is focused on considering several WSNs as a unique distributed one. This way, a user of the system is able to analyze a process under study as a whole instead of considering it as a set of different subsystems. This is the case in the evaluation of migratory waterbirds’ environment. In this case, it is usual to deploy several WSNs in different breeding areas. They are all interconnected and they measure different environmental parameters. However, this improvement in the data access flexibility may result in a loss of network performance and an increase in network power consumption. Focused on this problem, this paper evaluates different communication protocols: distributed and centralized, in order to determine the best trade-off for environmental monitoring in different migratory areas of waterbirds. D. F. Larios, J. M. Mora-Merchan, E. Personal, J. Barbancho, and C. León Copyright © 2013 D. F. Larios et al. All rights reserved. Tue, 04 Jun 2013 16:40:17 +0000 http://www.hindawi.com/journals/ijdsn/2013/507605/ In wireless sensor networks, a geographical positioning scheme is one of core technologies for sensor applications such as disaster monitoring, environment monitoring, and military services. For this reason, the research for range-free positioning schemes had progressing actively. And a density probability scheme based on the central limit theorem and normal distribution theory has been proposed to improve the location accuracy in nonuniform sensor network environments. The density probability scheme estimates 1-hop distance by using communication between nodes. After that, it estimates the final position of an unknown node. But the density probability scheme has a problem that it has equivalent 1-hop distance for all of nodes in the same area. To overcome this problem, we propose a novel sensor positioning scheme in non-uniform wireless sensor networks. As a result, the proposed scheme ensures the high accuracy of sensor positioning in non-uniform networks. To show the superiority of our proposed scheme, we compare it with the existing scheme such as DV-based position scheme. Our experimental results show that the proposed scheme improves by about 36% sensor positioning accuracy over the existing scheme on average even in non-uniform wireless sensor networks. Junho Park, Hyuk Park, Dong-ook Seong, and Jaesoo Yoo Copyright © 2013 Junho Park et al. All rights reserved. Tue, 04 Jun 2013 08:10:11 +0000 http://www.hindawi.com/journals/ijdsn/2013/216754/ Currently, sensor networks are widely used in various fields. Here secure operations are required for critical applications since the damages are significant if the network is compromised or disrupted. For the security of wireless sensor network, the earlier schemes typically employ asymmetric cryptography. These schemes are, however, often unsuitable for wireless sensor network due to the limited computational power and energy of the sensor nodes. To address this issue, various approaches have been developed, and the random key predistribution approach has been recognized as an effective approach. One shortcoming, however, is that a common key is not guaranteed to be found between any two nodes wanting to communicate. This paper proposes a new robust key predistribution scheme solving this problem, with which the security is not compromised even though the data exchanged between the nodes are tapped by an adversary. This is achieved by using the keys assigned based on the notion of eigenvalue and eigenvector of a square matrix of a pool of keys. Mathematical analysis and computer simulation reveal that the proposed scheme significantly reduces the overhead required for secure connectivity and energy consumption of sensor nodes compared to the existing approaches. Sung Jin Choi, Kyung Tae Kim, and Hee Yong Youn Copyright © 2013 Sung Jin Choi et al. All rights reserved. Mon, 03 Jun 2013 15:35:46 +0000 http://www.hindawi.com/journals/ijdsn/2013/385471/ In underwater acoustic sensor networks (UASNs), the propagation delay of acoustic signals is much longer than Radio Frequency (RF). There is spatial unfairness problem caused by space-time uncertainty. Hence, the design of Medium Access Control (MAC) is a challenging issue. In underwater, it not only considers transmission time but also takes location into account. In this paper, we propose Response to the Earliest Transmitter of RTS MAC (RET-MAC) protocol to solve the problem. RET-MAC adopts adaptive RTS Contention Phase (RTS CP) to determine the earliest transmitter of RTS. And CTS Delay Phase (CTS DP) is added to postpone sending CTS in order to avoid collision. In addition, we propose CTS back-off mechanism to adjust the length of CTS DP as needed. Contention back-off mechanism is used to reduce network congestion and increase fairness further. The simulation results show that our scheme can achieve higher fairness and throughput; at the same time it also guarantees lower energy consumption and delay. Shuming Xiong, Cheng Yuan, Lixin Tian, and Yongzhao Zhan Copyright © 2013 Shuming Xiong et al. All rights reserved. Sun, 02 Jun 2013 16:32:47 +0000 http://www.hindawi.com/journals/ijdsn/2013/602923/ In industrial contexts, most of process control applications use wired communication networks. The reliability of wired networks is indisputable and extensively demonstrated by several studies in the literature. However, it is important to consider several disadvantages provided by the use of wired technologies, like high deployment and maintenance costs and low network scalability. Although it is difficult to fully replace wired networks, wireless communication protocols have features which could undeniably affect in positive way the production mechanisms in factories. The wireless networks (WNs) are effectively used to detect and exchange information. The main communication protocols, currently available for WNs, however, do not support real-time periodic traffic flows which, as known, mainly characterize industrial networks. In this paper, we will analyze a real-time scheduling algorithm for both periodic and aperiodic traffic management, applied to networks based on IEEE 802.15.4 and Bluetooth, respectively. The main purpose of this research is to reduce, as much as possible, the packet loss on the channel, increasing at the same time the reliability of the wireless technology. Furthermore, the comparison between IEEE 802.15.4 and Bluetooth will allow to identify the more suitable communication protocol for industrial process control systems. Mario Collotta, Giovanni Pau, and Gianfranco Scatà Copyright © 2013 Mario Collotta et al. All rights reserved. Thu, 30 May 2013 11:51:29 +0000 http://www.hindawi.com/journals/ijdsn/2013/652495/ In wireless sensor networks, secure data aggregation is very important for reducing the quantity of data transmitted and prolonging the lifetime of wireless sensor networks. When wireless sensor networks are deployed in untrusted and hostile environments, their nodes are often compromised, which reduces the security and reliability of the transmitted data. Compromised nodes can inject erroneous data, selectively forward data to an adversary, impersonate legal nodes to join routing paths, and disrupt data transmission during the data-aggregation operation. Previous researchers have relied on reputation system to find compromised nodes and prevent attacks during the data-aggregation operation. In this paper, we propose an improved reliable, trust-based, and energy-efficient data-aggregation protocol for wireless sensor networks. We call the protocol the iRTEDA protocol, and it combines the reputation system, residual energy, link availability, and a recovery mechanism to improve secure data aggregation and ensure that the network is secure, reliable, and energy-efficient. Simulations have shown that the iRTEDA protocol exceeds the performances of other protocols from the perspectives of the accuracy of the data, the reliability of the routing path, the consumption of energy, and the lifetime of secure data aggregation. Chen-xu Liu, Yun Liu, and Zhen-jiang Zhang Copyright © 2013 Chen-xu Liu et al. All rights reserved. Wed, 29 May 2013 16:38:37 +0000 http://www.hindawi.com/journals/ijdsn/2013/369502/ With regard to the spread of innovative technologies, wireless sensor networks (WSNs) have great research interest in recent years. Although the WSN service is being facilitated, security related accidents are continuously incurring. In particular, many activities between mobile devices and sensor nodes take place without too much of protection of privacy information. To avoid these risks in WSN, we do need to devise the privacy care architecture to prevent the private data loss or breach especially in WSN. In this paper, we focus on WSN privacy issues with respect to mobile environments. We also suggest architecture to securely manage private data collected by WSN. It helps to protect the collected private data more efficiently and prevent the private data loss and breach. Kyong-Jin Kim and Seng-Phil Hong Copyright © 2013 Kyong-Jin Kim and Seng-Phil Hong. All rights reserved. Wed, 29 May 2013 09:24:44 +0000 http://www.hindawi.com/journals/ijdsn/2013/176293/ Rerouting has become an important challenge to Wireless Multimedia Sensor Networks (WMSNs) due to the constraints on energy, bandwidth, and computational capabilities of sensor nodes and frequent node and link failures. In this paper, we propose a traffic prediction-based fast rerouting algorithm for use between the cluster heads and a sink node in WMSNs (TPFR). The proposed algorithm uses the autoregressive moving average (ARMA) model to predict a cluster head’s network traffic. When the predicted value is greater than the predefined network traffic threshold, both adaptive retransmission trigger (ART) that contributes to switch to a better alternate path in time and trigger efficient retransmission behaviors are enabled. Performance comparison of TPFR with ant-based multi-QoS routing (AntSensNet) and power efficient multimedia routing (PEMuR) shows that they: (a) maximize the overall network lifespan by load balancing and not draining energy from some specific nodes, (b) provide high quality of service delivery for multimedia streams by switching to a better path towards a sink node in time, (c) reduce useless data retransmissions when node failures or link breaks occur, and (d) maintain lower routing overhead. Zhiyuan Li, Junlei Bi, and Siguang Chen Copyright © 2013 Zhiyuan Li et al. All rights reserved. Tue, 28 May 2013 17:30:18 +0000 http://www.hindawi.com/journals/ijdsn/2013/158569/ Video sensor networks are formed by the joining of heterogeneous sensor nodes, which is frequently reported as video of communication functionally bound to geographical locations. Decomposition of georeferenced video stream presents the expression of video from spatial feature set. Although it has been studied extensively, spatial relations underlying the scenario are not well understood, which are important to understand the semantics of georeferenced video and behavior of elements. Here we propose a method of mapping georeferenced video sequences for geographical scenes and use contextual random graphs to investigate semantic knowledge of georeferenced video, leading to correlation analysis of the target motion elements in the georeferenced video stream. We have used the connections of motion elements, both the correlation and continuity, to present a dynamic structure in time series that reveals clues to the event development of the video stream. Furthermore, we have provided a method for the effective integration of semantic and campaign information. Ultimately, the experimental results show that the provided method offers a better description of georeferenced video elements that cannot be achieved with existing schemes. In addition, it offers a new way of thinking for the semantic description of the georeferenced video scenarios. Jiangfan Feng and Hu Song Copyright © 2013 Jiangfan Feng and Hu Song. All rights reserved. Tue, 28 May 2013 14:44:34 +0000 http://www.hindawi.com/journals/ijdsn/2013/686713/ The key for cooperative collision avoidance (CCA) systems is the real-time and reliable delivery of safety-related messages among vehicles, which include periodical beacons and risk-triggered warning messages. In this paper, we first design a risk-aware dynamic medium-access control (R-MAC) protocol tailored for vehicular CCA applications. In this protocol, each frame is divided into two parts: TDMA segment for transferring beacons and CSMA segment for delivering warning messages. Then, we propose a stochastic model to predict the average total number of potential collisions in a platoon of vehicles, which determines the size of CSMA segment in the R-MAC protocol meticulously. Monte Carlo simulations validate that our model is reliable and practical. The performance of the R-MAC protocol is verified through theoretical analysis and extensive simulations under different traffic scenes. Simulation results show that R-MAC outperforms the traditional IEEE 802.11p protocol in terms of packets delivery rate and transmission delay, as well as the Jain's fairness index of the medium access between beacons and warning messages. Weijie Guo, Liusheng Huang, Long Chen, Hongli Xu, and Chenglin Miao Copyright © 2013 Weijie Guo et al. All rights reserved.