International Journal of Distributed Sensor Networks http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Minimized Cost Gateway Deployment in Cyber-Physical Systems Thu, 03 Sep 2015 06:21:55 +0000 http://www.hindawi.com/journals/ijdsn/2015/813656/ Wireless networks have been widely used in Cyber-Physical System (CPS) for data transmission. A CPS usually contains lots of sensors, and these sensors generate massive data. To make use of these data, we have to collect them through wireless communication. Sensors in a certain CPS do not always adopt same wireless technology, and these sensors formed heterogeneous wireless networks. Communication between different types of wireless networks can only be achieved by utilizing wireless gateways. In this paper, we address the problem of gateway placement for satisfying the bandwidth-requirement of each node by using minimum gateways. This problem can be formulated as a variant of Minimum Geometric Disk Cover problem which has been proved NP-complete. In order to solve our problem, one heuristic gateway placement algorithm and one grid-based heuristic algorithm are proposed. The result of simulation demonstrates that the heuristic algorithm can offer a good solution with big probability. Hao Wang, Jianzhong Li, and Hong Gao Copyright © 2015 Hao Wang et al. All rights reserved. An Experimental Performance Evaluation and Compatibility Study of the Bluetooth Low Energy Based Platform for ECG Monitoring in WBANs Wed, 02 Sep 2015 14:00:19 +0000 http://www.hindawi.com/journals/ijdsn/2015/645781/ A long term healthcare monitoring system requires battery operated devices with low-power technologies. Researchers tried to adapt various short-range technologies for Wireless Body Area Networks (WBANs) in ubiquitous health monitoring. The classical Bluetooth is known for its greedy power consumption, IrDA and NFC require line-of-sight conditions, and ANT has weak coexistence features and interference issues. A typical choice remains ZigBee/6LoWPAN over IEEE 802.15.4 based solutions in WBANs because of their low-power consumption. However, the recently proposed Bluetooth Low Energy (BLE) announced more compelling features in various aspects. Only few studies have been published supporting these claims on BLE. In this paper, we present a BLE based remote healthcare monitoring platform and we study its compatibility for ECG monitoring. ECG data requires continuous and real-time transmissions, making it particularly challenging for resource constrained devices. In our system, a BLE112 module from Bluegiga and a BLE USB dongle are used for WBAN. The performance of the system is evaluated experimentally and the results showed good potential of this proposed BLE platform in meeting the main QoS requirements of medical applications in terms of throughput, end-to-end delay, and packet error rate, while staying energy efficient. Farid Touati, Ochirkhand Erdene-Ochir, Waiser Mehmood, Ammad Hassan, Adel Ben Mnaouer, Brahim Gaabab, Mohd Fadlee A. Rasid, and Lazhar Khriji Copyright © 2015 Farid Touati et al. All rights reserved. A Game-Based Secure Localization Algorithm for Mobile Wireless Sensor Networks Tue, 01 Sep 2015 08:21:00 +0000 http://www.hindawi.com/journals/ijdsn/2015/642107/ The issue of node localization is a fundamental problem in wireless sensor networks. Recently, the localization problem for mobile sensor networks in hostile environment has received significant attention. Due to the mobility of the sensor nodes, it is more challenging to achieve node localization in attacked sensor networks than in static ones. To address these challenges, the paper presents a novel game-based secure localization algorithm. The nodes’ strategy level can be indicated through the results of trust evaluation and then by means of constructing reasonable strategy space and payoff function using game theory; all kinds of nodes within the network can achieve the optimal payoffs. The performance of our algorithm is evaluated by extensive simulation experiments. The simulation results show that the localization error of our proposed algorithm is lower than those of the existing ones in attacked environment. Tianyue Bao, Jiangwen Wan, Kefu Yi, and Qiang Zhang Copyright © 2015 Tianyue Bao et al. All rights reserved. Green and Friendly Communication for Sensor Networks Tue, 01 Sep 2015 07:55:16 +0000 http://www.hindawi.com/journals/ijdsn/2015/968167/ Changqiao Xu, Gabriel-Miro Muntean, Liang Zhou, and Xiaohong Jiang Copyright © 2015 Changqiao Xu et al. All rights reserved. Deadline Aware Retransmission Threshold Setting Protocol in Cyber-Physical Systems Tue, 01 Sep 2015 07:41:50 +0000 http://www.hindawi.com/journals/ijdsn/2015/271259/ Many time-sensitive applications impose high requirement on real-time response. There exist many algorithms and routing protocols for efficient data packet delivery. However, previous works set the same retransmission threshold for all the relay nodes along a delivery path. The method decreases the probability of a packet being transmitted through the delivery path within given deadline. In this paper, we focus on finding the optimal retransmission thresholds for the relay nodes, such that the summation of the probability of a packet being transmitted to the next relay node or destination node within the specified deadline is maximized. A distributed greedy algorithm that can be run on sensor node is proposed, which enables the sensor node to adaptively set the optimal retransmission threshold. To avoid dropping the packet forwarded to the destination within given deadline with high probability, we develop a packet dropped protocol based on probabilistic delay bound. Experimental results show that the proposed protocols have better performance. Ran Bi, Jianzhong Li, Hong Gao, and Quan Chen Copyright © 2015 Ran Bi et al. All rights reserved. Model-Based Sensitivity Analysis on Aerosol Optical Thickness Prediction Tue, 01 Sep 2015 06:54:25 +0000 http://www.hindawi.com/journals/ijdsn/2015/326132/ Prediction of aerosol optical thickness (AOT) is important to study worldwide climate changes. Researchers have built multiple AOT prediction models. However, few researches were focused on the validation of input attributes for AOT regression. In this paper, we proposed a support vector regression (SVR) model-based sensitivity analysis approach to order 35 MODIS input attributes according to their sensitivity to prediction outputs. Next, the attribute sensitivity orders are used for feature selection in the context of regression by removing insensitive attribute one at a time or by removing attributes whose sensitive orders are larger than number k. The experimental results based on the collocated data between MODIS and AERONET from 2009 to 2011 showed that the top 10 insensitive attributes can be screened to speed up prediction model computation with very little loss of accuracy. The results also suggested that the top sensitive attributes are the most informative attributes, requiring the highest precision for accurate AOT prediction. Thereby, our approach will be valuable for remote sensing scientists or atmospheric scientists to optimize the design precision of top sensitive attributes in scanning equipment like MODIS and therefore improve AOT retrieval accuracy. Bo Han, Xiaowei Gao, and Xiaohui Cui Copyright © 2015 Bo Han et al. All rights reserved. Modeling and Analyzing CSMA/CA Protocol for Energy-Harvesting Wireless Sensor Networks Tue, 01 Sep 2015 06:10:28 +0000 http://www.hindawi.com/journals/ijdsn/2015/257157/ Well-designed wireless sensor networks (WSNs) usually provide vital support for collecting, processing, and forwarding the real-time information in mission-critical applications where medium access control (MAC) protocols determine the channel access control capabilities and the energy consumption properties of these networks. This paper models the MAC protocol of CSMA/CA using timed automata on the message communication and the energy harvesting and analyzes the protocol through model checking of the major CTL properties. The modeling and analysis of CSMA/CA protocol with the comparative experiments give some performance results and also reveal that timing error may cause deadlock, and the accessibility is satisfied if no deadlock exists. Zhi Chen, Ya Peng, and Wenjing Yue Copyright © 2015 Zhi Chen et al. All rights reserved. Enterprise-Oriented IoT Name Service for Agricultural Product Supply Chain Management Mon, 31 Aug 2015 13:26:05 +0000 http://www.hindawi.com/journals/ijdsn/2015/308165/ Internet of Things (IoT) technologies have a great potential to improve the safety and quality of agricultural products. By providing near continuous monitoring from planting through harvesting and to our homes, IoT technologies are able to provide farm to fork visibility with all of the resulting benefits that accrue from that visibility. Unique identification provides the foundation of these benefits with a name service enabling efficient storage and retrieval of the data associated with each identifier. In this work, we present iotNS, a simple, efficient enterprise-oriented name service designed for agricultural products. The iotNS provides five times faster response than the standard GS1 ONS system. The iotNS has been deployed across five cities to enable the efficient storage and retrieval of information about agricultural products as they are tracked from the farm to the market. The deployment has shown that the visibility provided by iotNS is a mechanism that fosters cooperation and supply chain improvements among the enterprises using the iotNS. Yi Liu, He Wang, Junyu Wang, Kan Qian, Ning Kong, Kaijiang Wang, Lirong Zheng, Yiwei Shi, and Daniel W. Engels Copyright © 2015 Yi Liu et al. All rights reserved. Cloud-Assisted Scalable Video Delivery Solution over Mobile Ad Hoc Networks Mon, 31 Aug 2015 12:49:00 +0000 http://www.hindawi.com/journals/ijdsn/2015/205106/ Cloud computing is promising avenue for supporting high-performance and interactive streaming service. Making use of the clouds to flexibly increase the scale of video service system and provide fast search are key determinants for scalable mobile video streaming in order to ensure smooth playback experience. In this paper, we propose a novel Cloud-assisted Scalable Video Delivery Solution over mobile ad hoc networks (CSVD). CSVD makes use of the clouds to share responsibility for the load of resource management of media server, which supports fast resource searching and enhances system scalability. CSVD designs a new estimation model of resource maintenance scale in terms of quality of service- (QoS-) oriented dynamic balance between supply and demand, in order to economically use the clouds. A novel supplier scheduling algorithm that assigns resource suppliers for fast responding user request in terms of their load and serving capacity is proposed. Extensive tests show how CSVD achieves much better performance results in comparison with other state-of-the-art solutions. Lujie Zhong and Shijie Jia Copyright © 2015 Lujie Zhong and Shijie Jia. All rights reserved. Device-to-Device Users Clustering Based on Physical and Social Characteristics Mon, 31 Aug 2015 12:41:43 +0000 http://www.hindawi.com/journals/ijdsn/2015/165608/ This paper proposes a novel method for device-to-device (D2D) user clustering that allows wireless users in proximity to share common resources to save both system bandwidth and energy resources. The idea at the basis of our proposed cluster formation is to incorporate both social interactions and physical relationships among D2D terminals. Towards this goal, we propose two clustering approaches. The first one is based on the Chinese restaurant process (CRP), whereas the second one enhances the traditional CRP by defining a “distance-dependent Chinese restaurant process” (namely, DCRP). Numerical simulation results demonstrate superiority of our proposed clustering schemes in terms of system throughput, energy consumption, and energy efficiency over the existing schemes that rely only on physical distance. Li Wang, Giuseppe Araniti, Chunyan Cao, Wei Wang, and Yang Liu Copyright © 2015 Li Wang et al. All rights reserved. Compressive-Sensing-Based Video Codec by Autoregressive Prediction and Adaptive Residual Recovery Mon, 31 Aug 2015 12:39:22 +0000 http://www.hindawi.com/journals/ijdsn/2015/562840/ This paper presents a compressive-sensing- (CS-) based video codec which is suitable for wireless video system requiring simple encoders but tolerant, more complex decoders. At the encoder side, each video frame is independently measured by block-based random matrix, and the resulting measurements are encoded into compressed bitstream by entropy coding. Specifically, to reduce the quantization errors of measurements, a nonuniform quantization is integrated into the DPCM-based quantizer. At the decoder side, a novel joint reconstruction algorithm is proposed to improve the quality of reconstructed video frames. Firstly, the proposed algorithm uses the temporal autoregressive (AR) model to generate the Side Information (SI) of video frame, and next it recovers the residual between the original frame and the corresponding SI. To exploit the sparse property of residual with locally varying statistics, the Principle Component Analysis (PCA) is used to learn online the transform matrix adapting to residual structures. Extensive experiments validate that the joint reconstruction algorithm in the proposed codec achieves much better results than many existing methods with consideration of the reconstructed quality and the computational complexity. The rate-distortion performance of the proposed codec is superior to the state-of-the-art CS-based video codec, although there is still a considerable gap between it and traditional video codec. Ran Li, Hongbing Liu, Rui Xue, and Yanling Li Copyright © 2015 Ran Li et al. All rights reserved. Implementing PMIPv6 Protocol Based on Extended Service Set for IEEE 802.11 Infrastructure WLAN Mon, 31 Aug 2015 10:53:43 +0000 http://www.hindawi.com/journals/ijdsn/2015/828906/ With the popularity of IEEE 802.11 based wireless fidelity (Wi-Fi) portable devices, it becomes increasingly significant to support the mobile users carrying Wi-Fi devices to access the Internet of Things (IoT) so that the communications between the mobile users and the smart objects deployed in the IoT stay uninterrupted when the mobile users are in movement. A scheme using Extended Service Set- (ESS-) based architecture is presented to implement the proxy mobile IPv6 protocol, that is, PMIPv6, for IEEE 802.11 infrastructure Wireless Local Area Networks (WLANs). The key signaling packets together with their time sequences for the mobility management in the proposed scheme are proposed. Moreover, the handoff delay in the proposed scheme is derived, through which the performance of the proposed scheme is analyzed. Numerical analysis indicates that the proposed scheme considerably outperforms the existing scheme that uses the Basic Service Set (BSS) based architecture in terms of handoff delay in the case when the delay between Mobile Access Gateway (MAG) and local mobile anchor (LMA) is relatively large. Deqing Zhu, Lin Xu, Yi-hua Zhu, and Xianzhong Tian Copyright © 2015 Deqing Zhu et al. All rights reserved. Waypoint Graph Based Fast Pathfinding in Dynamic Environment Mon, 31 Aug 2015 09:12:49 +0000 http://www.hindawi.com/journals/ijdsn/2015/238727/ Pathfinding is a fundamental task in many applications including robotics, computer games, and vehicle navigation. Waypoint graph is often used for pathfinding due to its advantage in specifying the space and obstacles in a region. Currently the waypoint graph based pathfinding suffers from large computation overhead and hence long latency in dynamic environment, where the location of obstacles may change. In this paper, we propose a fast approach for waypoint graph based pathfinding in such scenario. We eliminate unnecessary waypoints and edges to make the graph sparse. And then we design a prediction-based local method to handle the dynamic change in the environment. Extensive simulation has been done and the results show that the proposed approach outperforms existing approaches. Weiping Zhu, Daoyuan Jia, Hongyu Wan, Tuo Yang, Cheng Hu, Kechen Qin, and Xiaohui Cui Copyright © 2015 Weiping Zhu et al. All rights reserved. Vehicular Ad Hoc Networks: Architectures, Research Issues, Methodologies, Challenges, and Trends Mon, 31 Aug 2015 09:03:07 +0000 http://www.hindawi.com/journals/ijdsn/2015/745303/ Vehicular ad hoc networks (VANETs) have been quite a hot research area in the last few years. Due to their unique characteristics such as high dynamic topology and predictable mobility, VANETs attract so much attention of both academia and industry. In this paper, we provide an overview of the main aspects of VANETs from a research perspective. This paper starts with the basic architecture of networks, then discusses three popular research issues and general research methods, and ends up with the analysis on challenges and future trends of VANETs. Wenshuang Liang, Zhuorong Li, Hongyang Zhang, Shenling Wang, and Rongfang Bie Copyright © 2015 Wenshuang Liang et al. All rights reserved. Development and Validation of a Portable Human Body Joint Power Test System Mon, 31 Aug 2015 07:26:20 +0000 http://www.hindawi.com/journals/ijdsn/2015/341072/ A portable human body joint power test system was developed using inertial sensor technology and wireless Bluetooth acquisition technology. A detailed description of the internal structure of the system and the data processing method involved is provided. The test system uses the cubic spline interpolation method, which is very convenient for obtaining the maximum peak points of muscle isotonic contraction joint power curves under different loads. Moreover, the system is portable and can be deployed in the classroom and the playground for education and testing. The test system is very useful in many respects, such as athlete selection and daily strength training. We established a model of our subject using a balanced proportion scaling method in the inverse dynamics software AnyBody modeling system. The muscle model uses the Hill muscle model. The data import interface program was written in the parameterized model definition language AnyScript to import data. The raw data was smoothed with a Butterworth low-pass filter. Dumbbell curl simulation was conducted in AnyBody. The results of the simulation and those of the real test system were tested using the paired samples t-test method; the value of Sig was determined to be greater than 0.05, indicating no significant difference and that the data of the test system are valid. Lin Li, Zhongqiu Ji, Ye Xia, and Rui Gong Copyright © 2015 Lin Li et al. All rights reserved. Data Mining for the Internet of Things: Literature Review and Challenges Sun, 30 Aug 2015 12:46:07 +0000 http://www.hindawi.com/journals/ijdsn/2015/431047/ The massive data generated by the Internet of Things (IoT) are considered of high business value, and data mining algorithms can be applied to IoT to extract hidden information from data. In this paper, we give a systematic way to review data mining in knowledge view, technique view, and application view, including classification, clustering, association analysis, time series analysis and outlier analysis. And the latest application cases are also surveyed. As more and more devices connected to IoT, large volume of data should be analyzed, the latest algorithms should be modified to apply to big data. We reviewed these algorithms and discussed challenges and open research issues. At last a suggested big data mining system is proposed. Feng Chen, Pan Deng, Jiafu Wan, Daqiang Zhang, Athanasios V. Vasilakos, and Xiaohui Rong Copyright © 2015 Feng Chen et al. All rights reserved. Handling Interservice Time Constraints in Wireless Networks Sun, 30 Aug 2015 12:26:51 +0000 http://www.hindawi.com/journals/ijdsn/2015/280109/ Cyber physical systems collect plenty of information from physical world. This information must be transmitted to the base station immediately to support the making of controlling orders since the physical world keeps transforming rapidly. Such a fact needs the support of real-time transmitting in CPS. Real-time traffic often has some extra QoS requirements. For example, regulating the interservice time, which is the time between two consecutive transmissions of a link, is essential for the real-time traffic in wireless networks. A guarantee of the interservice time of a single user is a precondition to support the normal operating of a system. As far as we know, none of previous work can guarantee the performance on the interservice time. Motivated by this, we design a framework for interservice time guaranteed scheduling. We first define a new capacity region of networks with a strict interservice time guarantee. It is an extension of the well-accepted definition on basic capacity region. Then we propose a novel scheduling policy that is both throughput-optimal and interservice time guaranteed. Simulation results show the policy performs well in interservice time and throughput. Xu Zheng, Jianzhong Li, and Hong Gao Copyright © 2015 Xu Zheng et al. All rights reserved. Online Optimization of Collaborative Web Service QoS Prediction Based on Approximate Dynamic Programming Sun, 30 Aug 2015 12:24:50 +0000 http://www.hindawi.com/journals/ijdsn/2015/452492/ More recently, with the increasing demand of web services on the World Wide Web used in the Internet of Things (IoTs), there has been a growing interest in the study of efficient web service quality evaluation approaches based on prediction strategies to obtain accurate quality-of-service (QoS) values. However, it is obvious that the web service quality changes significantly under the unpredictable network environment. Such changes impose very challenging obstacles to web service QoS prediction. Most of the traditional web service QoS prediction approaches are implemented only using a set of static model parameters with the help of designer’s a priori knowledge. Unlike the traditional QoS prediction approaches, our algorithm in this paper is realized by incorporating approximate dynamic programming- (ADP-) based online parameter tuning strategy into the QoS prediction approach. Through online learning and optimization, the proposed approach provides the QoS prediction with automatic parameter tuning capability, and prior knowledge or identification of the prediction model is not required. Therefore, the near-optimal performance of QoS prediction can be achieved. Experimental studies are carried out to demonstrate the effectiveness of the proposed ADP-based prediction approach. Xiong Luo, Hao Luo, and Xiaohui Chang Copyright © 2015 Xiong Luo et al. All rights reserved. The Study on Media Access Control Protocol for Wireless Network in Library Sun, 30 Aug 2015 11:08:38 +0000 http://www.hindawi.com/journals/ijdsn/2015/792542/ Wireless technology will be widely used in libraries with the development of the mobile network in the near future. This paper focuses on MAC protocol for wireless network based on ultra-wideband band (UWB) to solve the problems of real-time and reliability in the wireless transmitting. According to the particular signal characteristics such as low energy consumption and excellent location, we propose a multichannel MAC protocol (UWBIMAC) based on status-adaptive to choose the channel mechanism. Simulation results show that the protocol had the ability of stronger antijamming, improved network throughput, and provided better average delay performance than IEEE802.15.4 MAC, IEEE802.11 MAC, and other UWBIMAC protocols. This method could be used in the process of wireless transmission service in the library or other similar scenarios. To a certain extent, it solves the problem of real-time and reliable performance in the process of wireless communication. Wen Zeng, Junsheng Zhang, Ying Li, and Peng Qu Copyright © 2015 Wen Zeng et al. All rights reserved. Context-Aware Recommendation via Graph-Based Contextual Modeling and Postfiltering Sun, 30 Aug 2015 10:04:59 +0000 http://www.hindawi.com/journals/ijdsn/2015/613612/ Context-aware recommender systems generate more relevant recommendations by adapting them to the specific contextual situation of the user and have become one of the most active research areas in the recommender systems. However, there remains a key issue as how contextual information can be used to create intelligent and useful recommender systems. To assist the development and use of context-aware recommendation capabilities, we propose a graph-based framework to model and incorporate contextual information into the recommendation process in an advantageous way. A contextual graph-based relevance measure (CGR) is specifically designed to assess the potential relevance between the target user and the items further used to make an item recommendation. We also propose a probabilistic-based postfiltering strategy to refine the recommendation results as contextual conditions are explicitly given in a query. Depending on the experimental results on the two datasets, the CGR-based method is much superior to the traditional collaborative filtering methods, and the proposed postfiltering method is much effective in context-aware recommendation scenario. Hao Wu, Kun Yue, Xiaoxin Liu, Yijian Pei, and Bo Li Copyright © 2015 Hao Wu et al. All rights reserved. Wireless Vehicular Sensor and Ad Hoc Networks 2015 Sun, 30 Aug 2015 09:54:17 +0000 http://www.hindawi.com/journals/ijdsn/2015/257146/ Deyun Gao, Chuan Heng Foh, Boon-Chong Seet, and Oliver W. W. Yang Copyright © 2015 Deyun Gao et al. All rights reserved. A Dynamic Processing System for Sensor Data in IoT Sun, 30 Aug 2015 09:52:23 +0000 http://www.hindawi.com/journals/ijdsn/2015/750452/ With the development of the Internet of Things (IoT for short), innumerable Wireless Sensor Networks (WSNs) are deployed to capture the information of environmental status in the surrounding physical environment. The data from WSNs, called sensor data, are generated in high frequency. Similar to data of other open-loop applications, for example, network monitoring data, sensor data are heterogeneous, redundant, real-time, massive, and streaming. Hence, sensor data cannot be treated as the IoT business data, which brings complexity and difficulty to information sharing in the open-loop environment. This paper proposes a dynamic sensor data processing (SDP) system to capture and process sensor data continuously on the basis of data streaming technology. Particle Swarm Optimization (PSO) algorithm is employed to train threshold dynamically for data compression avoiding redundancy. With the help of rules setting, the proposed SDP is able to detect exception situations. Meanwhile, the storage models in SQL and NOSQL databases are analyzed and compared trying to seek an appropriate type of database for sensor data storage. The experimental results show that our SDP can compress sensor data through dynamically balancing the accuracy and compression rate and the model on NOSQL database has better performance than the model on SQL database. Minbo Li, Yanling Liu, and Yuanfeng Cai Copyright © 2015 Minbo Li et al. All rights reserved. Enhanced Asymmetric Bilinear Model for Face Recognition Sun, 30 Aug 2015 09:50:56 +0000 http://www.hindawi.com/journals/ijdsn/2015/218514/ Bilinear models have been successfully applied to separate two factors, for example, pose variances and different identities in face recognition problems. Asymmetric model is a type of bilinear model which models a system in the most concise way. But seldom there are works exploring the applications of asymmetric bilinear model on face recognition problem with illumination changes. In this work, we propose enhanced asymmetric model for illumination-robust face recognition. Instead of initializing the factor probabilities randomly, we initialize them with nearest neighbor method and optimize them for the test data. Above that, we update the factor model to be identified. We validate the proposed method on a designed data sample and extended Yale B dataset. The experiment results show that the enhanced asymmetric models give promising results and good recognition accuracies. Wenjuan Gong, Weishan Zhang, Jordi Gonzàlez, Yan Ren, and Zhen Li Copyright © 2015 Wenjuan Gong et al. All rights reserved. Privacy Information Security Classification for Internet of Things Based on Internet Data Sun, 30 Aug 2015 09:40:54 +0000 http://www.hindawi.com/journals/ijdsn/2015/932941/ A lot of privacy protection technologies have been proposed, but most of them are independent and aim at protecting some specific privacy. There is hardly enough deep study into the attributes of privacy. To minimize the damage and influence of the privacy disclosure, the important and sensitive privacy should be a priori preserved if all privacy pieces cannot be preserved. This paper focuses on studying the attributes of the privacy and proposes privacy information security classification (PISC) model. The privacy is classified into four security classifications by PISC, and each classification has its security goal, respectively. Google search engine is taken as the research platform to collect the related data for study. Based on the data from the search engine, we got the security classifications of 53 pieces of privacy. Xiaofeng Lu, Zhaowei Qu, Qi Li, and Pan Hui Copyright © 2015 Xiaofeng Lu et al. All rights reserved. Two-Dimensional Code Based Spatiotemporal Modeling and Its Application in Object Tracing Sun, 30 Aug 2015 09:10:13 +0000 http://www.hindawi.com/journals/ijdsn/2015/527217/ Space-time consistency is of great importance for mapping things from physical world to cyber world, which could be one of the fundamental issues in constructing cyber-physical system (CPS). A two-dimensional code spatiotemporal modeling method is proposed in this paper. We apply the two-dimensional code as an information carrier to store object’s characteristics (object’s ID, attributes, instructions, spatiotemporal data, etc.), the smartphone as a mobile device to obtain the object’s real-time spatiotemporal data with its system time and GPS module; then the object’s spatiotemporal information can be transmitted and stored in a backend server with a database. Meanwhile, the object’s spatiotemporal information can also be inquired by smartphone users and other web users. A use case that applied this proposed method to trace object’s smartphone information is described later, and the result shows that tracing objects with two-dimensional code has many advantages, such as fast reading and transmitting, low cost, and robust, confidential, and strong readability; furthermore, the proposed modeling method keeps the consistency of object’s time and space in CPS. Yanghua Gao, Zhihua Zhang, Huanwen Wang, and Hailiang Lu Copyright © 2015 Yanghua Gao et al. All rights reserved. A Multimodel Based Range Query Processing Algorithm for Information Collection in CPS Sun, 30 Aug 2015 09:09:23 +0000 http://www.hindawi.com/journals/ijdsn/2015/403267/ A multimodel based range query processing algorithm is proposed to solve the information collection task for the CPSs, which utilizes multiple probability models to depict the data distribution of a sensor node. The execution of the multimodel based algorithm consists of two phases, which are the preprocessing phase and the query processing phase. During the preprocessing phase, multiple models are constructed for each node according to their historical data. During the query processing phase, a suitable model is selected from the multiple models with the help of a sampling based algorithm, which is used to process the query. As the multimodel based algorithm needs to sample data from the network, it can waste energy more than that of the single model based algorithm in some cases, which does not sample data from the network. The cost of the multimodel based and single model based algorithm is analyzed. A cost model based algorithm is proposed to select a better algorithm to process a query from the two algorithms. Experimental results show that the cost model based algorithm can save 13.3% energy consumption more than that of the single model based algorithm. Guilin Li, Xing Gao, Longjiang Guo, JunCong Lin, Ying Gao, and Minghong Liao Copyright © 2015 Guilin Li et al. All rights reserved. A Genetic-Algorithm-Based Approach for Task Migration in Pervasive Clouds Sun, 30 Aug 2015 09:01:05 +0000 http://www.hindawi.com/journals/ijdsn/2015/463230/ Pervasive computing is converging with cloud computing which becomes pervasive cloud computing as an emerging computing paradigm. Users can run their applications or tasks in pervasive cloud environment in order to gain better execution efficiency and performance leveraging powerful computing and storage capacities of pervasive clouds through task migration. During task migration, there are possibly a number of conflicting objectives to be considered when making migration decisions, such as less energy consumption and quick response, in order to find an optimal migration path. In this paper, we propose a genetic algorithms- (GAs-) based approach which is effective in addressing multiobjective optimization problems. We have performed some preliminary evaluations of the proposed approach which shows quite promising results, using one of the classical genetic algorithms. The conclusion is that GAs can be used for decision making in task migrations in pervasive clouds. Weishan Zhang, Shouchao Tan, Qinghua Lu, Xin Liu, and Wenjuan Gong Copyright © 2015 Weishan Zhang et al. All rights reserved. A Phoenix++ Based New Genetic Algorithm Involving Mechanism of Simulated Annealing Sun, 30 Aug 2015 08:46:51 +0000 http://www.hindawi.com/journals/ijdsn/2015/806708/ Genetic algorithm is easy to fall into local optimal solution. Simulated annealing algorithm may accept nonoptimal solution at a certain probability to jump out of local optimal solution. On the other hand, lack of communication among genes in MapReduce platform based genetic algorithm, the high-performance distributed computing technologies or platforms can further increase the execution efficiency of these traditional genetic algorithms. To this end, we propose a novel Phoenix++ based new genetic algorithm involving mechanism of simulated annealing. Simulated annealing genetic algorithm has two distinctive characteristics. First, it is the synthesis of the conventional genetic algorithm and the simulated annealing algorithm. This characteristic guarantees our proposed algorithm has a higher probability of getting the global optimal solution than traditional genetic algorithms. The other is that our algorithm is a parallel algorithm running on the high-performance parallel platform Phoenix++ instead of a conventional serial genetic algorithm. Phoenix++ implements the MapReduce programming model that processes and generates large data sets with our parallel, distributed algorithm on a cluster. The experiments indicate that the convergence speed of GA algorithm is significantly faster after adding the simulated annealing algorithm on Phoenix++ platform. Luokai Hu, Jin Liu, Chao Liang, Fuchuan Ni, and Hang Chen Copyright © 2015 Luokai Hu et al. All rights reserved. IDUC: An Improved Distributed Unequal Clustering Protocol for Wireless Sensor Networks Sun, 30 Aug 2015 08:41:03 +0000 http://www.hindawi.com/journals/ijdsn/2015/415702/ Due to the imbalanced energy consumption among nodes in wireless sensor networks, some nodes die prematurely, which decreases the network lifetime. To solve this problem, existing clustering protocols usually construct unequal clusters by exploiting uneven competition radius. Taking their imperfection on designing the uneven competition radius and intercluster communication into consideration, this paper proposes an improved distributed unequal clustering protocol (IDUC) for wireless sensor networks, where nodes are energy heterogeneous and scattered unevenly. The cores of IDUC are the formation of unequal cluster topology and the construction of intercluster communication routing tree. Compared with previous protocols, IDUC is suitable for various network scenarios, and it can balance the energy consumption more efficiently and extend the lifetime of networks significantly. Chuanqing Chen, Li Feng, Xin Gu, Jiguo Yu, Dongxiao Yu, and Baogui Huang Copyright © 2015 Chuanqing Chen et al. All rights reserved. An Approach for Prediction of Acute Hypotensive Episodes via the Hilbert-Huang Transform and Multiple Genetic Programming Classifier Sun, 30 Aug 2015 08:36:56 +0000 http://www.hindawi.com/journals/ijdsn/2015/354807/ Acute hypotensive episodes (AHEs) are one of the hemodynamic instabilities with high mortality rate that is frequent among many groups of patients. This study presents a methodology to predict AHE for ICU patients based on big data time series. The experimental data we used is mean arterial pressure (MAP), which is transformed from arterial blood pressure (ABP) data. Then, the Hilbert-Huang transform method was used to calculate patient’s MAP time series and some features, which are the bandwidth of the amplitude modulation, the frequency modulation, and the power of intrinsic mode function (IMF), were extracted. Finally, the multiple genetic programming (Multi-GP) is used to build the classification models for detection of AHE. The methodology is applied in the datasets of the 10th PhysioNet and Computers Cardiology Challenge in 2009 and Multiparameter Intelligent Monitoring for Intensive Care (MIMIC-II). We achieve the accuracy of 83.33% in the training set and 91.89% in the testing set of the 2009 challenge’s dataset and the 84.13% in the training set and 82.41% in the testing set of the MIMIC-II dataset. Dazhi Jiang, Liyu Li, Bo Hu, and Zhun Fan Copyright © 2015 Dazhi Jiang et al. All rights reserved.