International Journal of Distributed Sensor Networks The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. CompaRob: The Shopping Cart Assistance Robot Sun, 07 Feb 2016 15:14:49 +0000 Technology has recently been developed which offers an excellent opportunity to design systems with the ability to help people in their own houses. In particular, assisting elderly people in their environments is something that can significantly improve their quality of life. However, helping elderly people outside their usual environment is also necessary, to help them to carry out daily tasks like shopping. In this paper we present a person-following shopping cart assistance robot, capable of helping elderly people to carry products in a supermarket. First of all, the paper presents a survey of related systems that perform this task, using different approaches, such as attachable modules and computer vision. After that, the paper describes in detail the proposed system and its main features. The cart uses ultrasonic sensors and radio signals to provide a simple and effective person localization and following method. Moreover, the cart can be connected to a portable device like a smartphone or tablet, thus providing ease of use to the end user. The prototype has been tested in a grocery store, while simulations have been done to analyse its scalability in larger spaces where multiple robots could coexist. Jorge Sales, Jose V. Martí, Raúl Marín, Enric Cervera, and Pedro J. Sanz Copyright © 2016 Jorge Sales et al. All rights reserved. Modeling of Multihop Wireless Sensor Networks with MAC, Queuing, and Cooperation Sun, 07 Feb 2016 08:57:06 +0000 We present a Markovian decision process (MDP) framework for multihop wireless sensor networks (MHWSNs) to bound the network performance of both energy constrained (EC) networks and energy harvesting (EH) networks, both with and without relay cooperation. The model provides the fundamental performance limit that a MHWSN can theoretically achieve, under the general constraints from medium access control, routing, and energy harvesting. We observe that the analyses for EC and EH networks fall into two branches of MDP theory, which are finite-horizon process and infinite-horizon process, respectively. The performance metrics for EC and EH networks are different. For EC networks, an appropriate metric is the network lifetime; for EH networks, an appropriate metric is, for example, the network throughput. To efficiently solve the models with high dimension, for the EC networks, we propose a novel computational algorithm by taking advantage of the stochastic shortest path structure of the problem; for the EH networks, we propose a dual linear programming based algorithm by considering the sparsity of the transition matrix. Under the unified MDP framework, numerical results demonstrate the advantages of cooperation for the optimal performance, in both EC and EH networks. Jian Lin and Mary Ann Weitnauer Copyright © 2016 Jian Lin and Mary Ann Weitnauer. All rights reserved. A Statistical Approach in Designing an RF-Based Human Crowd Density Estimation System Thu, 04 Feb 2016 09:25:42 +0000 The study of human crowd density estimation (H-CDE) using radio frequency is limited due to the nature of wireless medium and the advancement of visual-based systems. There were two statistical methods, namely, One-Way Analysis of Variance and Design of Experiment applied in designing the H-CDE system. One-Way Analysis of Variance is used to investigate the difference in signal attenuation between dynamic and static crowds. The Design of Experiment is utilized to identify significant crowd properties that affect wireless signal propagation. The significant factors were later trained into the H-CDE algorithm for the purpose of estimating the human crowd density in a defined sector. A sector comprising three placements of 2.4 GHz ZigBee wireless nodes continuously reported the received signal strength indicator to the main node. The results showed that the H-CDE system was 75.00% and 70.83% accurate in detecting the low and medium human crowd density, respectively. A signal path loss propagation model was also proposed to assist in predicting the human crowd density. The human crowd properties verified by using the statistical approach may offer a new side of understanding and estimating the human crowd density. S. Y. Fadhlullah and Widad Ismail Copyright © 2016 S. Y. Fadhlullah and Widad Ismail. All rights reserved. SDN-Based Active Content Networking Sun, 31 Jan 2016 09:34:09 +0000 This paper proposes a Software Defined Networking- (SDN-) based active content networking architecture for future media environments. The proposed architecture aims to provide customized delivery of various types of media content in order to satisfy users’ demand and service requirements. To this end, we have developed an active content processing model which provides in-network content processing through service objects that are integral parts of active content. The main benefits provided by the proposed model are high flexibility and creativity to meet the evolving future media environments. Tai-Won Um, Gyu Myoung Lee, and Jinsul Kim Copyright © 2016 Tai-Won Um et al. All rights reserved. CP-ABE with Hidden Policy from Waters Efficient Construction Thu, 28 Jan 2016 16:39:28 +0000 ABE provides a good way for access controlling in cloud computing. However, in many application scenarios, access policies for encryption also should be protected since they may directly contain sensitive information. For example, in smart grid, the access policies may contain the private information about underlying data, data owner or the data recipients, and disclosing some sensitive access policies could result in negative publicity, or loss of market revenue. In this paper, we present a CP-ABE scheme with hidden policy from Waters efficient construction. In our scheme, the access policy is hidden by using the composite order bilinear groups and can be expressed with LSSS. Our scheme is proved CPA secure under four statics assumptions. Zhiwei Wang and Mingjun He Copyright © 2016 Zhiwei Wang and Mingjun He. All rights reserved. QoE-Driven, Energy-Aware Video Adaptation in 5G Networks: The SELFNET Self-Optimisation Use Case Sun, 24 Jan 2016 10:25:40 +0000 Sharp increase of video traffic is expected to account for the majority of traffic in future 5G networks. This paper introduces the SELFNET 5G project and describes the video streaming use case that will be used to demonstrate the self-optimising capabilities of SELFNET’s autonomic network management framework. SELFNET’s framework will provide an advanced self-organizing network (SON) underpinned by seamless integration of Software Defined Networking (SDN), Network Function Virtualization (NFV), and network intelligence. The self-optimisation video streaming use case is going beyond traditional quality of service approaches to network management. A set of monitoring and analysis components will facilitate a user-oriented, quality of experience (QoE) and energy-aware approach. Firstly, novel SON-Sensors will monitor both traditional network state metrics and new video and energy related metrics. The combination of these low level metrics provides highly innovative health of network (HoN) composite metrics. HoN composite metrics are processed via autonomous decisions not only maintaining but also proactively optimising users’ video QoE while minimising the end-to-end energy consumption of the 5G network. This contribution provided a detailed technical overview of this ambitious use case. James Nightingale, Qi Wang, Jose M. Alcaraz Calero, Enrique Chirivella-Perez, Marian Ulbricht, Jesús A. Alonso-López, Ricardo Preto, Tiago Batista, Tiago Teixeira, Maria Joao Barros, and Christiane Reinsch Copyright © 2016 James Nightingale et al. All rights reserved. Resource Aware Routing in Heterogeneous Opportunistic Networks Thu, 21 Jan 2016 14:27:45 +0000 In heterogeneous scenarios, nodes greatly differ with respect to their capabilities and mobility patterns. Moreover, episodic connectivity in opportunistic networks further aggravates the problem of finding a suitable next-hop to obviate unnecessary utilization of network resources. In this paper, we present a Multiattribute Routing Scheme (MARS) based on “Simple Multiattribute Rating Technique” (SMART) that collects samples of vital information about a node’s different characteristics. This stochastic picture of a node behavior in multiple dimensions is then effectively employed in calculating its next-hop fitness. We also devise a method based on learning rules of neural networks which dynamically determines relative importance of each dimension to maximize next-hop utility of a node. With simulations, using synthetic and real mobility traces against well-known utility-based schemes, we show that MARS can achieve better delivery ratios despite introducing limited redundancy within the network. Sadaf Yasmin, Rao Naveed Bin Rais, and Amir Qayyum Copyright © 2016 Sadaf Yasmin et al. All rights reserved. Prefetching Scheme for Massive Spatiotemporal Data in a Smart City Thu, 21 Jan 2016 07:39:09 +0000 Employing user access patterns to develop a prefetching scheme can effectively improve system I/O performance and reduce user access latency. For massive spatiotemporal data, traditional pattern mining methods fail to directly reflect the spatiotemporal correlation and transition rules of user access, resulting in poor prefetching performance. This paper proposed a prefetching scheme based on spatial-temporal attribute prediction, named STAP. It maps the history of user access requests to the spatiotemporal attribute domain by analyzing the characteristics of spatiotemporal data in a smart city. According to the spatial locality and time stationarity of user access, correlation analysis is performed and variation rules are identified for the history of user access requests. Further, the STAP scheme mines the user access patterns and constructs a predictive function to predict the user’s next access request. Experimental results show that the prefetching scheme is simple yet effective; it achieves a prediction accuracy of 84.3% for access requests and reduces the average data access response time by 44.71% compared with the nonprefetching scheme. Lian Xiong, Zhengquan Xu, Hao Wang, Shan Jia, and Li Zhu Copyright © 2016 Lian Xiong et al. All rights reserved. Deep Belief Networks for Fingerprinting Indoor Localization Using Ultrawideband Technology Thu, 21 Jan 2016 07:07:30 +0000 With the increasing requirement of localization services in indoor environment, indoor localization techniques have drawn a lot of attention. In recent years, fingerprinting localization techniques have been proved to be effective in indoor localization tasks. Due to the complexity and variability of indoor environment, some traditional geometric localization techniques based on time of arrival (TOA), received signal strength (RSS), or direction of arrival (DOA) may cause big position errors. Unlike common geometric localization methods, fingerprinting localization techniques estimate the position of target by creating a pattern matching model or regression model for the measurement. Therefore, a suitable learning model is the key of a fingerprinting location system. This paper presents a fingerprinting based localization technique using deep belief network (DBN) and ultrawideband (UWB) signals in an office environment. Some location-dependent parameters extracted from channel impulse response (CIR) are used as signatures to build the fingerprinting database. The construction of DBN which is based on the fingerprinting database is also discussed in this paper. Experiment results show that, with appropriate fingerprinting database and model structure, the location system can get desired accuracy. Junhai Luo and Huanbin Gao Copyright © 2016 Junhai Luo and Huanbin Gao. All rights reserved. Errors Nature of the Narrowband PLC Transmission in Smart Lighting LV Network Tue, 19 Jan 2016 12:54:46 +0000 This paper presents characteristics of the Frame Error Rate versus Signal to Noise Ratio obtained from Smart Lighting LV network. These characteristics are the results of carrying out many field-trials in three locations. During the one-year tests period lighting systems evolved from the traditional, gas-discharge not individually dimmable system to LED or gas-discharge Smart Lighting system controlled with the use of PLC technology every lamp individually. A different influence of the frame length on the characteristic for the gas-discharge and LED LV networks led to examining the bit errors distribution. The bit errors distribution characteristics of the narrowband PLC transmission over the Smart Metering LV network are also presented in this paper. All the presented data in this work are the results of the long time field-trials, which were verified in the lab conditions. Piotr Kiedrowski Copyright © 2016 Piotr Kiedrowski. All rights reserved. Implementing Smart Factory of Industrie 4.0: An Outlook Tue, 19 Jan 2016 12:22:57 +0000 With the application of Internet of Things and services to manufacturing, the fourth stage of industrialization, referred to as Industrie 4.0, is believed to be approaching. For Industrie 4.0 to come true, it is essential to implement the horizontal integration of inter-corporation value network, the end-to-end integration of engineering value chain, and the vertical integration of factory inside. In this paper, we focus on the vertical integration to implement flexible and reconfigurable smart factory. We first propose a brief framework that incorporates industrial wireless networks, cloud, and fixed or mobile terminals with smart artifacts such as machines, products, and conveyors. Then, we elaborate the operational mechanism from the perspective of control engineering, that is, the smart artifacts form a self-organized system which is assisted with the feedback and coordination blocks that are implemented on the cloud and based on the big data analytics. In addition, we outline the main technical features and beneficial outcomes and present a detailed design scheme. We conclude that the smart factory of Industrie 4.0 is achievable by extensively applying the existing enabling technologies while actively coping with the technical challenges. Shiyong Wang, Jiafu Wan, Di Li, and Chunhua Zhang Copyright © 2016 Shiyong Wang et al. All rights reserved. QoS Model of WSNs Communication in Smart Distribution Grid Tue, 19 Jan 2016 10:27:30 +0000 This paper presents an integrated modeling method providing superior Quality of Service (QoS) for wireless sensor networks (WSNs) which is suitable for smart distribution grid (SDG) communication. Traditional QoS model based on IEEE802.15.4 protocol cannot meet the communication requirements of multipriority data in smart distribution grid. In order to meet the specification of power system communication, a new QoS-enabled medium access control (MAC) model based on unfair competition channel access mechanism (UCCAM) is developed in this paper. The proposed model can ensure that the communication system of WSN provides different Qualities of Service for different priority data. According to different requirements for the communication time, the data of SDG are divided into three types: high priority, middle priority, and low priority data. The state transition of buffering queue data in node is described by a three-dimensional Markov chain model. Delay time, effective throughput rate, and channel collision rate models are developed, respectively, to evaluate communication performance of WSN applied in smart distribution grid. The simulation results show that the proposed model can provide different Qualities of Service for different priority data and is more efficient than the IEEE802.15.4e standard and the traditional methods. Ruju Fang, Jianping Wang, Wei Sun, and Qiyue Li Copyright © 2016 Ruju Fang et al. All rights reserved. Efficient Dynamic Replicated Data Possession Checking in Distributed Cloud Storage Systems Mon, 18 Jan 2016 16:30:16 +0000 More and more organizations outsource their data to remote cloud servers (RCSs). Data owners rent the cloud service providers (CSPs) infrastructure to store their unlimited resources by paying fees metered in month or gigabyte. For increasing the availability and scalability of data, the data owners store their data replicas on multiple servers across multiple data centers. Data owners should ensure that the CSPs actually store all their copies according to the service contract. In this paper, we present an efficient dynamic multicopies possession checking scheme that has the following properties: (1) the data owner uses fully homomorphic encryption (FHE) algorithm to generate multiple copies; (2) the scheme supports data block dynamic operation; (3) the scheme supports third-party auditor’s public validation. Finally, security analysis and experimental results show that our scheme can resist forgery, replacement, and replay attack and perform better than some other related scheme published recently. Jinxia Wei, Jianyi Liu, Ru Zhang, and Xinxin Niu Copyright © 2016 Jinxia Wei et al. All rights reserved. An Improved ARIMA-Based Traffic Anomaly Detection Algorithm for Wireless Sensor Networks Mon, 18 Jan 2016 12:06:32 +0000 Traffic anomaly detection is emerging as a necessary component as wireless networks gain popularity. In this paper, based on the improved Autoregressive Integrated Moving Average (ARIMA) model, we propose a traffic anomaly detection algorithm for wireless sensor networks (WSNs) which considers the particular imbalanced, nonstationary properties of the WSN traffic and the limited energy and computing capacity of the wireless sensors at the same time. We systematically analyze the characteristics of WSN traffic, the causes of WSN abnormal traffic, and the latest related research and development. Specifically, we improve the traditional time series ARIMA model to make traffic prediction and judge the traffic anomaly in a WSN. Simulated and real WSN traffic data gathered from University of North Carolina are used to carry out simulations on Matlab. Simulation results and comparative analyses demonstrate that our proposed WSN traffic anomaly detection scheme has better anomaly detection accuracy than traditional traffic anomaly detection algorithms. Qin Yu, Lyu Jibin, and Lirui Jiang Copyright © 2016 Qin Yu et al. All rights reserved. Application-Driven OAM Framework for Heterogeneous IoT Environments Mon, 18 Jan 2016 06:46:16 +0000 We present a novel approach for providing a comprehensive operational picture of heterogeneous networks by collecting system information from physical, data-link, network and application layers using extended methods and mechanisms for OAM, which take into account particularities of persistent access heterogeneity and IoT. A heterogeneous OAM (H-OAM) framework is proposed with a toolset for streamlined failure detection and isolation, and automated performance measurement and monitoring. The framework combines extended standardized OAM toolsets for physical and data-link layers with multiple well-defined and recognized IP network layer toolsets, which introduces possibilities for a tactical view of the monitored system and quick root cause analysis with unified interpretation and cross-correlation of horizontal and vertical levels. A practical deployment of an H-OAM system is presented and its use is demonstrated in a live mobile IoT testbed environment where performance is a function of a wide variety of physical layer parameters that need to be tuned and monitored by the operator. Results of two concrete usage scenarios performed in cooperation with two largest Slovenian mobile operators demonstrate how continuity check and connectivity verification, and performance diagnostics are conducted for Web-based IoT applications and network services of a live operational environment. Janez Sterle, Urban Sedlar, Miha Rugelj, Andrej Kos, and Mojca Volk Copyright © 2016 Janez Sterle et al. All rights reserved. An Efficient Algorithm for Energy Management in Wireless Sensor Networks via Employing Multiple Mobile Sinks Mon, 18 Jan 2016 06:09:44 +0000 Energy saving in wireless sensor networks is a fundamental issue as most sensor nodes are powered by batteries. The deployment of mobile sinks can alleviate the imbalance of energy consumption among sensor nodes, thereby prolonging the network lifetime. In this paper, we study the energy management problem in sensor networks, using multiple mobile sinks. We first formulate the problem as a novel data collection problem and then propose an efficient algorithm for it. The key challenge in the design of the proposed algorithm is how to balance the workload among mobile sinks and the energy consumption among sensor nodes through the control of the movement of mobile sinks. We finally evaluate the performance of the proposed algorithm through experimental simulation. Experimental results show that the proposed algorithm is very promising, which can improve the energy efficiency and the quality of data transmission in the sensor network significantly. Jiugen Shi, Xing Wei, and Wei Zhu Copyright © 2016 Jiugen Shi et al. All rights reserved. Advancing Building Energy Management System to Enable Smart Grid Interoperation Sun, 17 Jan 2016 12:11:21 +0000 With the emerging concept of smart grid, a customer’s building facility is able to consume, generate, and store energy. At the center of the facility, an energy management system is required to perform an efficient energy management and to enable smart grid interoperation. However, the existing EMS is designed only for the management function and does not support the interoperation. To resolve the issue, this paper designs the interoperation function and proposes a new EMS model, named Premises Automation System (PAS), that also inherits the existing management function. To identify functional requirements, we bring out four design aspects out of energy services. Then, we design two categories of interoperable energy services to achieve customer interoperation. To demonstrate the feasibility of PAS, we implement and deploy a testbed in a campus. We conduct experiments with a microgrid scenario and present interesting measurements and findings. Eun-Kyu Lee Copyright © 2016 Eun-Kyu Lee. All rights reserved. Strongly Unforgeable and Efficient Proxy Signature Scheme with Fast Revocation Secure in the Standard Model Sun, 17 Jan 2016 12:06:04 +0000 The existing proxy signature schemes with the proxy revocation function are proven to be malleable and do not possess strong unforgeability. Motivated by these concerns, a new proxy signature scheme with fast revocation is proposed, and it can be proved that the proposed scheme can achieve strong unforgeability in the standard model. By using this scheme, the original signer can generate the delegation warrant for the proxy signer, and at the same time, he/she can perform the immediate revocation to completely terminate the delegation when needed. Analyses show that the proposed scheme satisfies all of the security requirements of proxy signature and has shorter public parameters than the existing ones. Liaojun Pang, Huiyang Zhao, Xia Zhou, and Huixian Li Copyright © 2016 Liaojun Pang et al. All rights reserved. Recent Efficient Iterative Algorithms on Cognitive Radio Cooperative Spectrum Sensing to Improve Reliability and Performance Sun, 17 Jan 2016 11:31:44 +0000 In cognitive radio (CR), cooperative spectrum sensing (CSS) has been extensively explored to be accounted for in a spectrum scanning method that permits secondary users (SUs) or cognitive radio users to utilize discovered spectrum holes caused by the absence of primary users (PUs). This paper focuses on optimality of analytical study on the common soft decision fusion (SDF) CSS based on different iterative algorithms which confirm low total probability of error and high probability of detection in detail. In fact, all steps of genetic algorithm (GA), particle swarm optimization (PSO), and imperialistic competitive algorithm (ICA) will be well mentioned in detail and investigated on cognitive radio cooperative spectrum sensing (CRCSS) method. Then, the performance of CRCSS employing GA-, PSO-, and ICA-based scheme is analysed in MATLAB simulation to show superiority of these schemes over other conventional schemes in terms of detection and error performance with very less complexity. In addition, the ICA-based scheme also reveals noticeable convergence and time running performance in comparison to other techniques. Mohsen Akbari, Ahmed Wasif Reza, Kamarul Ariffin Noordin, Kaharudin Dimyati, Mohsen Riahi Manesh, and Mohammad Nour Hindia Copyright © 2016 Mohsen Akbari et al. All rights reserved. Applications of Cognitive Radio Networks: Recent Advances and Future Directions Thu, 14 Jan 2016 08:40:57 +0000 Sung W. Kim, Miao Pan, Gyanendra Prasad Joshi, Orhan Gazi, Jianhua He, and Marceau Coupechoux Copyright © 2016 Sung W. Kim et al. All rights reserved. Security and Privacy Mechanisms for Sensor Middleware and Application in Internet of Things (IoT) Tue, 12 Jan 2016 13:18:55 +0000 Namje Park, Hongxin Hu, and Qun Jin Copyright © 2016 Namje Park et al. All rights reserved. Mobility Support for Next-Generation Wireless Sensor Networks Tue, 12 Jan 2016 13:16:37 +0000 Guangjie Han, Zhangbing Zhou, Longjun Dong, Joel J. P. C. Rodrigues, and Kamesh Namuduri Copyright © 2016 Guangjie Han et al. All rights reserved. Pilot-Less Time Synchronization for OFDM Systems: Application to Power Line Receivers Tue, 12 Jan 2016 09:26:57 +0000 Power line networks provide high-speed broadband communications without the need for new wirings. However, these networks present a hostile environment for high-speed data communications. The most common modulation method used in such systems is OFDM, since it copes effectively with noise, multipath, fading selectivity, and attenuation. A potential drawback of OFDM is its sensitivity to receiver synchronization imperfections, such as timing and sampling frequency offsets. Although several approaches have been proposed for estimating the time and frequency offset, they are based on the use of pilot sequences that are not available in power line communication standards. More importantly, they focus on isolated algorithms for compensating either time or frequency offsets without providing a complete, low complexity, OFDM receiver architecture that mitigates jointly time and frequency errors. This paper focuses on providing an OFDM receiver architecture that can be compatible with many power line standards. Extensive simulation studies show under realistic channel and noise conditions that the proposed receiver provides enhanced robustness to synchronization imperfections as compared to conventional approaches. Aris S. Lalos, Athanasios Vgenis, Fotios Gioulekas, and Michael Birbas Copyright © 2016 Aris S. Lalos et al. All rights reserved. Two-Layer Hidden Markov Model for Human Activity Recognition in Home Environments Tue, 12 Jan 2016 09:26:04 +0000 Activities of Daily Livings (ADLs) refer to the activities that are carried out by an individual for everyday living. Recognition of ADLs is key element for building intelligent and pervasive environments. We propose a two-layer HMM to build a ADLs recognition model that can represent the mapping between low-level sensor data and high-level activity based on the binary sensor data. We used embedded sensor with appliances or object to get object used sequence data as well as object name, type, interaction time, and location. In the first layer, we use location data of object used sensor to predict the activity class and in the second layer object used sequence data to determine the exact activity. We perform comparison with other activity recognition models using three real datasets to validate the proposed model. The results show that the proposed model achieves significantly better recognition performance than other models. M. Humayun Kabir, M. Robiul Hoque, Keshav Thapa, and Sung-Hyun Yang Copyright © 2016 M. Humayun Kabir et al. All rights reserved. Hybrid Wireless Sensor Networks: Theory and Design Tue, 12 Jan 2016 06:42:37 +0000 Qilian Liang, Tariq S. Durrani, Yiming Pi, and Sherwood W. Samn Copyright © 2016 Qilian Liang et al. All rights reserved. Sink Location Protection Protocols Based on Packet Sending Rate Adjustment Sun, 10 Jan 2016 10:35:04 +0000 Sink location protection is critical to the viability of sensor networks as the central point of failure. Most existing work related to sink location protection focuses on local traffic analysis attack. In this paper, we study the sink location protection problem under a more powerful type of attack, the global traffic analysis attack. In order to hide the sink location, a protocol based on packet sending rate adjustment (SRA) is proposed. By controlling the packet sending rate of each node according to the current number of source nodes, SRA conceals the real traffic volume generated by source nodes and hence disguises the location of the sink. For further reducing the communication cost, we propose a light weight SRA protocol (L-SRA), which protects the sink location while significantly decreasing the communication cost. Performance of both SRA and L-SRA has been validated by theoretical analysis and simulation results. Juan Chen, Zhengkui Lin, Yan Liu, Ying Hu, and Xiaojiang Du Copyright © 2016 Juan Chen et al. All rights reserved. Low Power OFDM Receiver Exploiting Data Sparseness and DFT Symmetry Wed, 06 Jan 2016 13:10:41 +0000 An undersampling technique appropriate for Orthogonal Frequency Division Multiplexing (OFDM) that can be implemented with low complexity hardware is presented. The OFDM receiver can operate in undersampling mode, 75% of the time. One of the advantages of the proposed scheme is the reduction down to the half of the power consumed by the Analog Digital Converter (ADC) and the Fast Fourier Transform (FFT). The FFT memory requirements for sample storage can also be reduced and its operating speed can be increased. Simulations were performed for two Quadrature Amplitude Modulation orders (16-QAM and 32-QAM), two options for the FFT size (1024 and 4096), two alternative input symbol structures for the inverse FFT (IFFT), and several sparseness levels and samples substitution options. The Symbol Error Rate (SER) and image reconstruction examples are used to show that a full reconstruction or a very low error can be achieved. Although the proposed undersampling method is evaluated for wired channel, it can also be used without any modification to wireless Single Input Single Output (SISO) systems (with an expected SER degradation). It can also be used with Multiple Input Multiple Output (MIMO) systems when an appropriate arrangement of the IFFT input symbols is adopted. Nikos Petrellis Copyright © 2016 Nikos Petrellis. All rights reserved. Security Improvement on Biometric Based Authentication Scheme for Wireless Sensor Networks Using Fuzzy Extraction Tue, 05 Jan 2016 07:30:43 +0000 Wireless sensor networks are used to monitor physical or environmental conditions. However, authenticating a user or sensor in wireless sensor networks is more difficult than in traditional networks owing to sensor network characteristics such as unreliable communication networks, resource limitation, and unattended operation. As a result, various authentication schemes have been proposed to provide secure and efficient communication. He et al. suggested a robust biometrics-based user authentication scheme, but Yoon and Kim indicated that their scheme had several security vulnerabilities. The latter then proposed an advanced biometrics-based user authentication scheme; in this paper, we analyze this advanced scheme and perform a cryptanalysis. Our analysis shows that Yoon and Kim’s scheme has various security weaknesses such as a biometric recognition error, a user verification problem, lack of anonymity and perfect forward secrecy, session key exposure by the gateway node, vulnerability to denial of service attacks, and a revocation problem. Therefore, we suggest countermeasures that can be implemented to solve these problems and then propose a security-enhanced biometrics-based user authentication scheme using fuzzy extraction that conforms to the proposed countermeasures. Finally, we conduct a security analysis for the proposed biometrics-based user authentication scheme. Younsung Choi, Youngsook Lee, and Dongho Won Copyright © 2016 Younsung Choi et al. All rights reserved. Unbalanced Threshold Based Distributed Data Collection Scheme in Multisink Wireless Sensor Networks Mon, 04 Jan 2016 09:07:16 +0000 In multisink wireless sensor networks, synchronized data collection among multiple sinks is a significant and challenging task. In this paper, we propose an unbalanced threshold based distributed data collection scheme to reconstruct the synchronized sensed data of the whole sensor network in all sinks. The proposed scheme includes the unbalanced threshold based distributed top- query algorithm and the distributed iterative hard thresholding algorithm. By computing unbalanced thresholds and pruning unnecessary element exchanging, each sink can synchronize the top- aggregated values efficiently via the unbalanced threshold based distributed top- query algorithm. After that, the synchronized sensed data of the whole sensor network can be reconstructed through the distributed iterative hard thresholding algorithm in a distributed and cooperative manner. We show through experiments that the proposed scheme can reduce the interaction times and decrease the number of transmitted data and that of computed data compared to the existing schemes while maintaining the similar data reconstruction accuracy. The communication and computational performances of the proposed scheme are also analyzed in detail in the paper. Guorui Li, Ying Wang, Cong Wang, and Yiying Liu Copyright © 2016 Guorui Li et al. All rights reserved. Towards the Integration between IoT and Cloud Computing: An Approach for the Secure Self-Configuration of Embedded Devices Thu, 31 Dec 2015 15:29:23 +0000 The secure boot-up and setup of Internet of Things (IoT) devices connected over the Cloud represent a challenging open issue. This paper deals with the automatic configuration of IoT devices in a secure way through the Cloud, in order to provide new added-value services. After a discussion on the limits of current IoT and Cloud solutions in terms of secure self-configuration, we present a Cloud-based architecture that allows IoT devices to interact with several federated Cloud providers. In particular, we present two possible scenarios, that is, single Cloud and a federated Cloud environments, interacting with IoT devices and we address specific issues of both. Moreover, we present several design highlights on how to operate considering real open hardware and software products already available in the market. Antonio Puliafito, Antonio Celesti, Massimo Villari, and Maria Fazio Copyright © 2015 Antonio Puliafito et al. All rights reserved.