Showing papers in "Journal of Communications in 2014"

Unmanned Aerial Vehicles for Power Line Inspection: A Cooperative Way in Platforms and Communications

Abstract: The emerging technology of unmanned aerial vehicle (UAV) has become more affordable and practicable for power line inspections. In this paper, we propose a multi-platform UAV system and multi-model communication system for highly efficient power line inspection tasks in China. The different UAVs cooperatively serve as long-distance imaging, short dis- tance imaging and communication relay. The high quality im- age/video is transmitted in realtime to the on-site control station for UAV navigation and far end office for analysis. Our experi- ence shows that the cooperative inspection for multi-UAVs can achieve a much higher efficiency than traditional inspection methods.  Index Terms—UAV, hexrotor, fixed wing, tethered rotor, pow- er line inspection, communication relay, datalink

Smart Home Area Networks Protocols within the Smart Grid Context

Abstract: The Internet of things (IoT) applications are becoming one of the emerging smart grid enabling technologies. Smart home appliances are one the beneficiary of such applications. Machine-to-Machine and Man-to-Machine are the basic IoT communication platforms that enable home appliances to communicate with each other to be more efficiently operated. In a recent search for the IoT communication protocols that are utilized in smart home appliances, there was no inclusive reference that contains and describes the smart home area networks and guides the research and development (R&D) professionals to select the suitable protocol for an application. This paper presents a comprehensive review of the home area network (HAN) communication protocols that are used to enable bidirectional communication between the home owners, utilities and smart home appliances. The paper presents the most utilized HANs wired and wireless communication protocols and discusses their characteristics, advantages and disadvantages.

Cyber Security Analytics: A Stochastic Model for Security Quantification Using Absorbing Markov Chains

Abstract: Most of the current research in security analysis has been centered on identifying threats and vulnerabilities and providing suitable defense mechanisms to improve the robustness of the network and systems. While this approach is attractive, it provides limited insight into understanding the impact these attacks have on the overall security goals of the network and the system. Attack Graph as a model lends itself nicely to the analysis of the security state of a network. Most of the Attack graph based metrics proposed in the literature are one dimensional; however the research community has acknowledged the fact that security needs to be treated as a multidimensional concept. In this paper, we utilize stochastic modeling techniques using Attack graphs to define a complementary suite of quantitative metrics to aid the security engineer in visualizing the current as well as future security state of the network and optimizing the necessary steps to harden the enterprise network from external threats. We present experimental results from applying this model on a sample network to demonstrate the practicality of our approach.

A Novel Weighted Centroid Localization Algorithm Based on RSSI for an Outdoor Environment

Abstract: Location information is one of the most important services in the field of wireless sensor networks (WSNs). Compared to other proposed non-interactive localization algorithms, the weighted centroid localization scheme only uses the received signal strength indication (RSSI), which makes it simple to implement and robust to variations in the propagation environment. In this paper, we propose a weight-compensated weighted centroid localization algorithm based on RSSI for an outdoor environment. By theoretically analyzing, the proposed algorithm has the advantage of lower complexity, little prior information and lower power consumption. The simulation results show that the proposed algorithm is better than AMWCL-RSSI (Anchor_optimized Modified Weighted Centroid Localization based on RSSI) and WCL (Weighted Centroid Localization) in terms of the localization accuracy. Our real experimental results also show that WCWCL-RSSI (Weight-Compensated Weighted Centroid Localization Based on RSSI) is better than WCL in terms of the localization accuracy. 

Cellular Coverage Optimization for Indoor Visible Light Communication and Illumination Networks

Abstract: In visible light communication (VLC) systems, cellular networks are required for large indoor environment and built as a kind of new networks when combining the LED illumination, named communication and illumination networks (CIN). The co-channel interference (CCI) between adjacent cells leads to large areas of communication dead zones. Users covered by access points (APs) within illumination region are not necessarily covered within communication region and vice versa. In order to achieve seamless coverage, it is necessary to mitigate CCI and maximize the effective coverage of communication and illumination synchronously. In this paper, a coverage optimization model is built when APs share the same frequency resources. Genetic algorithm is used for optimizing LED arrangements, semi-angles at half-power and heights, and improving SINR and illuminance in CIN. The results show that the communication and illumination can be approximate seamless coverage after optimization and about 75% communication coverage improvement is achieved when illumination requirement is fulfilled. The solution has a better downlink throughput and complexity than state-of-the-art solutions when cellular coverage is approximate. 

Diamond: An Improved Fat-tree Architecture for Large- scale Data Centers

Abstract: With the widespread deployment of cloud services, data center networks are developing toward large-scale, multi- path networks. To support the new trend, some novel network architectures have been proposed, and Fat-tree is one of the most promising architecture and gets a lot of attention because it has good performance on aggregate bandwidth with a simple topology. This paper presents Diamond, an improved Fat-tree architecture for large-scale data centers. Diamond replaces all the aggregation switches of Fat-tree with edge switches and connects directly edge switches to core switches. By this alteration, the average route path and End-to-End (ETE) delay in Diamond are 10% less than that in Fat-tree. We design FAR, a simple and high-efficient routing method for Diamond. In FAR, each switch requires only hundreds of route entries to support a large-scale network with tens of thousands servers, and to build FAR routing tables, switches exchange very few messages. Diamond and its FAR routing are verified through OPNET simulations. 

Uncertain Quadratic Minimum Spanning Tree Problem

Abstract: The quadratic minimum spanning tree problem is to find a spanning tree on a graph that minimizes a quadratic objective function of the edge weights. In this paper, the quadratic minimum spanning tree problem is concerned on the graph with edge weights being assumed as uncertain variables. The notion of the uncertain quadratic -minimum spanning tree is introduced by using the uncertain chance constraints. It is shown that the problem of finding an uncertain quadratic - minimum spanning tree can be handled in the framework of the deterministic quadratic minimum spanning tree problem requiring no particular solving methods.

A Survey of MAC Protocols Design Strategies and Techniques in Wireless Ad Hoc Networks

Abstract: Medium access control (MAC) protocols provide a means to nodes to access the wireless medium efficiently and collision free to the best of their ability. In this paper we provide a survey of MAC protocols developed for mobile ad hoc (MANETs) in the past based on certain methods and techniques such as multiple radios, multiple channels and specialized beamforming antennas. We discuss some of the MAC protocols designed for wireless sensor networks (WSNs) and their applicability in a MANET environment. There are some similarities between MANETs and WSN's in general but there is also critical differences between the two that affect the design of MAC protocols for both these networks. Traditionally, MAC protocols have been classified on the basis of two broad categories of contention free and contention based MAC protocols but a number of new algorithms proposed in the recent past merge the two schemes together in a single MAC solution and thus there is a need for a new classification approach. MANETs have their unique constraints and characteristics. In this classification, we will discuss various MAC solutions proposed in the past in the light of these constraints and characteristics. We do not intend to explain each and every protocol since the number of MAC solutions proposed in the past decade or so is very large. The purpose of this article is to give the readers a general idea on the various techniques and methods used in literature to develop MAC protocols for MANETs. The techniques range from algorithmic changes such as cross-layer design to enhancement in hardware such as directional antennas.

Quantum network via partial entangled state

Abstract: In this article we designed a quantum network consists of four nodes using pairs of partial entangled state (Werner-state). The nodes of this network are connected via Dzyaloshiniskii-Moriya (DM) interaction. The entanglement is quantified between all different nodes using Wootters concurrence. It is shown that there is a maximum entangled state generated between two nodes which are connected indirectly. The degree of entanglement depends on the direction of switching the interaction. Index Terms—Entanglement, quantum network, dzyaloshiniskii-Moriya (DM) interaction, Entangled State

Image encryption algorithms based on chaos through dual scrambling of pixel position and bit

Abstract: As the current popular chaos-based image encryption algorithms with the permutation–diffusion structure have security flaws of no immunity to attack. A new image encryption algorithm was proposed based on the analysis of current algorithms, which can well resist the chosen-plaintext and the chosen-ciphertext attacks. The algorithm uses Kent chaotic map to generate key streams, and produces the parameters of the chaotic system and the iteration times according to the characteristics of plaintext pixels and input key. Firstly, the positions of pixels were shuffled totally with the chaotic sequence. Secondly, the 0 and 1 bit positions of image pixels were scrambled by using another chaotic sequence generated by the input key. The experimental results show that the algorithm cannot only resist the chosen plaintext attack and chosen ciphertext attack but also achieve better cryptographic properties,such as key space, statistical analysis.

Three-Dimensional Node Localization Algorithm for WSN Based on Differential RSS Irregular Transmission Model

Abstract: The localization accuracy of the conventional three- dimensional (3D) node localization algorithm based on received signal strength (RSS) is restricted by the random signal strength fluctuation caused by the irregular propagation environments. In this paper, we propose an improved localization algorithm based on a differential RSS distance estimation algorithm to minimize the influence of the path loss exponent error. Furthermore, considering the influence of degree of irregularity (DOI), we propose a new radio model and obtain numerically the relation between DOI and the variation of signal transmission ranges. A spherical shell with certain finite thickness is then used to characterize the transmission range irregularity. The simulation results show the path loss exponent has no effect on localization error in the proposed algorithm. The localization errors for various DOIs are significantly lower than the conventional 3D algorithm for different densities of anchor nodes.

Fast Inter-Mode Decision Algorithm for High-Efficiency Video Coding Based on Textural Features

Abstract: Due to the problems of the new generation of video coding standard HEVC (High-Efficiency Video Coding), such as high computational complexity and the large computation, This paper proposes a fast inter-mode decision algorithm based on image texture features and by using Sobel operator the edge features are extracted from CU which is partitioned by simulation, and then the final partitioning size of CU is determined by the texture features contained in the current CU block of simulation partitioning. By using this method, both of the traverse layers of CU depth and the times of inter predictive coding are reduced. Thus the computational complexity of coding terminal is lowered effectively. The experimental results showed that, compared with inter-mode decision algorithm in HEVC standard, the time of this method is saved 45.35% on average with little loss of coding efficiency and PSNR

Impulsive Noise Cancellation for MIMO Power Line Communications

Abstract: Power line channels are often badly corrupted by impulsive noise. In this paper, an impulsive noise cancellation method for MIMO power line communication is proposed. First, the received signal is transformed into frequency domain and MIMO detection is carried out. Then, the detected signal is transformed back to time domain and the noise estimation can be obtained by subtracting detected signal from the original received signal, the result is the estimation of the noise in time domain. Finally, impulsive noise can be found out from the estimation of the noise by a threshold detector and canceled from the original received signal. The de-noised output is transformed back to space-time domain to repeat the impulsive noise cancellation process until the output is unchanged. Simulation results show that the proposed method can suppress in PLC channel impulsive noise and improve bit-error ratio performance in multi-wire power line communication.  Index Terms— , power line communications; multiple input multiple output; space time block code

Improved artificial fish-swarm algorithm based on adaptive vision for solving the shortest path problem

Abstract: To solve basic artificial fish-swarm algorithm(AFSA)'s drawbacks of low convergence rate in the latter stage, a large amount of computation and easiness of trapping in local optimal solution, caused by the constant vision of the artificial fish, an improved artificial fish-swarm algorithm based on adaptive vision(AVAFSA) was proposed The improved algorithm only adjusted the vision of the preying behavior of artificial fish to make the vision gradually decrease with the increase of the number of iterations of the algorithm When the value became less than half the initial value, it made the value be equal to half the initial value The proposed improved artificial fish swarm algorithm was applied to the static shortest path problem based on road network to provide customers with the best path Simulation results depict the improved algorithm has higher convergence rate, a smaller amount of calculation, and is more accurate and stable than the basic AFSA and ant colony optimization(ACO)

Enhanced performance of SAC-OCDMA system based on SPD detection utilizing EDFA for access networks

Abstract: In this paper, we present the impact of an EDFA (Erbium Doped Fibre Amplifier) for high data rate in Spectral Amplitude Coding Optical Code Division Multiple Access (SAC-OCDMA) networks. A Single photodiode (SPD) detection structure for SACOCDMA system is presented. The SPD detection can be flexibly constructed for any weight and number of users by using a single photodiode. Several advantages of using EDFA for simultaneous noise suppression and improved the signal quality. Thus, these features show the SPD combined with EDFA be a solution to enhance the overall system performance of SAC-OCDMA access networks. Based on the theoretical and simulation evaluation, Modified Double Weight (MDW) code is shown to provide a much better performance compared to existing SAC-OCDMA codes. The ability of the MDW code based SAC-OCDMA system utilizing EDFA to support simultaneous transmissions at different data rate has been successfully established through the simulated results of the (622 Mbps×3 users) at bit error rate of 10. 

Similar handwritten Chinese character recognition based on deep neural networks with big data

Abstract: The recognition rates of the traditional similar handwritten Chinese character recognition(SHCCR) systems are not very high due to the restriction of feature extraction methods.In order to improve the recognition accuracy,a new method based on deep neural networks(DNN) was proposed to learn effective features automatically and conduct recognition.The method of how to generate similar handwritten Chinese character sets was introduced.The architecture of the DNN for SHCCR was presented.The performances with respect to different training data scale was compared.The experimental results show that,DNN can learn features automatically and efficiently.The proposed DNN can achieve better performance comparing with support vector machine(SVM) and nearest neighbor classifier(1-NN) based on gradient features.Especially,with the increase of training data the recognition rate of DNN is improved observably,indicating that large training data is crucial for the performance of DNN.

Software Defined Wireless Network Architecture for the Next Generation Mobile Communication: Proposal and Initial Prototype

Abstract: —In this paper, we propose a network architecture and a methodology to implement a network simulator and a system prototype for the software defined wireless networks with the reprogrammable capability brought by a SDWN controller. The software defined wireless network architecture oriented for the 5G network is defined with a multi-tiered cloud controller and the Openflow interface. The implementation architecture of system prototype for the software defined wireless network is based on Openflow. Finally, we evaluate and implement some new features and scenarios as applications and services with the Floodlight controller. The new features and scenarios include the cloud radio access/handover, the radio topology discovery, the extended location monitoring and the energy management. The experiments results show us that the proposed network architecture and the implementation methodology works well in this prototype.

Fuzzy-based Clustering of Web Services' Quality of Service: A Review

Abstract: Clustering has been proposed in numerous researches on web services due to its ability in enhancing computational efficiency. The objective of this paper is to present a review on web services clustering and to propose fuzzy clustering of web services' based on quality of service (QoS). A total of 49 manuscripts, collected from ISI, SCOPUS and Google Scholar indexing databases, were critically reviewed. The review revealed that there is no report has been published before regarding fuzzy-based clustering of web services' QoS. It also revealed the importance of clustering in ensuring the efficiency of web services delivery particularly in their discovery, selection and recommendation processes. The results of the proposed fuzzy clustering can be used as reference to guide requestors to subscribe suitable services. They could also be implemented as the inference components for fuzzy- based web services applications. For future work, the generated clustering results will be implemented in web services QoS monitoring application. Index Terms—Clustering, fuzzy clustering, Fuzzy C-Means, QoS clustering, web services clustering.

A Novel Link Stability and Energy Aware Routing with Tradeoff Strategy in Mobile Ad Hoc Networks

Abstract: Mobile ad hoc networks (MANETs) are self- organizing, rapidly deployable networks without any fixed infrastructure. In MANETs, mobile terminals can move freely, which cause frequent link breakage. Due to the dynamic nature of the network, finding a stable route for transmitting data is a challenging task. In order to adapt to the topological changes and provide some quality of service (QoS), this paper propose a novel link stability and energy aware routing algorithm with tradeoff strategy, and implement it on Ad Hoc On-demand Distance Vector Routing Protocol (AODV), namely NLSEA- AODV. The new protocol sets up routes with high stability in route discovery based on link stability and node energy information, and predict the breaking link in route maintenance. Besides, the routing takes a route stability-hop count tradeoff strategy to select routes with high stability and low hop count. Simulation results show that the new protocol has a better overall performance than original AODV protocol, which improved the network utilization greatly.

OpenSatRelaying: a Hybrid Approach to Real-Time Audio- Video Distribution over the Internet

Abstract:  Abstract—In spite of massive research efforts devoted to the advance of the technologies for large-scale live distribution of audio-video IP streams, no totally satisfying solutions seem to have emerged so far. CDNs are still expensive and P2P-TV systems face substantial delay limitations. As the deployment of a global terrestrial IP multicast infrastructure still looks far, turning the attention to satellite-based multicast would seem a sensible choice. However, the cost of such technology has been a stumbling block until now. That is where the CHARMS architecture comes in. It is designed to take advantage of the formidable properties of the satellite without requiring a generic user to install any sort of satellite receiver or dish. Its cornerstone is the recursive terrestrial relaying of satellite streams a number of properly equipped hosts are able to receive. The present paper relates about the results of the OpenSatRelaying project, aimed at the implementation and testing of the CHARMS architecture.

A Practical Approach for Load Balancing in LTE Networks

Abstract: Load imbalance among multi-cell has tremendous impact on the network performance. The previous researches on load balancing place focus on maximizing the load balancing index of the network and cannot always guarantee the best performance of network's key performance indicators (KPIs). In this paper, taking both the network resource limitation and users' data rate demand into account, we aim to simultaneously optimize both the load balancing index and network average load for quality-of-service (QoS) requirements services, while maximizing the network utility for other services. Moreover, we proposed a practical algorithm with low complexity. Comparing with the previous methods, simulation results show that the proposed method can achieve better network performances, such as lower new call blocking rate and higher network resource utilization. Index Terms—LTE, multi-cell, load balancing (LB), quality-of- service (QoS), multi-objective optimization problem

Study on Denial of Service against Underwater Acoustic Networks

Abstract: In ocean exploration and other maritime engineering, UAN (Underwater Acoustic Networks) is bound to play more important roles. Thinking of the serious environment UAN operates, safety and security must be guaranteed first. Among the possible attacks against UAN, DoS (Denial of Service) is a class of commonly-used methods. The basic procedures of different DoS attacks are analyzed and some of the DoS attacks against UAN are simulated to investigate their effects to lower the performances of UAN. Flooding, wormholes and selective forwarding attacks against UAN are studied via simulation. At last, some recommendations are given to improve the security performance of UAN based upon the results of simulations.

Application of EMD Denoising Approach in Noisy Blind Source Separation

Abstract: Blind Source Separation (BSS) algorithms based on the noise-free model are not applicable when the Signal Noise Ratio (SNR) is low In view of this situation, our solution is to denoise the mixtures with additive white Gaussian noise firstly, and then use BSS algorithms This paper proposes a piecewise Empirical Mode Decomposition (EMD) thresholding approach to denoise mixtures with strong noise This approach can distinguish the noise-dominated IMFs and signal-dominated IMFs, and then respectively apply different thresholdings methods Simulation results show that compared with the Wavelet denoising, the proposed approach has a better denoising performance, and can remarkably enhance the separation performance of BSS algorithms, especially when the signal SNR is low

New Remapping Strategy for PDCCH Scheduling for LTE-Advanced Systems

Abstract: In LTE-A, efficient Physical Downlink Control Channel (PDCCH) scheduling is fundamental to ensuring not only users' Quality of Service (QoS) but also bursty data channels. However, the limited resource available for PDCCH has proven to be a major issue that hampers users' scheduling. By principle, every user equipment (UE) admitted into the network is expected to be scheduled by the control channel prior to gaining access to data channel's resources (i.e. Physical Resource Blocks-PRBs). However, the limited PDCCH resources in traditional systems usually result to some UEs being deprived from accessing PRBs because they have not been scheduled for resource access by PDCCH. This situation is a major connectivity challenge in LTE-A systems. As such, we have proposed a new remapping strategy for PDCCH resource scheduling based on linear transformation matrix. Our scheme remaps the users' search spaces using a transformation function derived from their previous search spaces and the available resources in order to efficiently address PDCCH resource utilization issue. Extensive simulation results show that our new scheme is able to reduce UEs' average blocking probability and as well improve PDCCH resource utilization. Notwithstanding this enhancement, our scheme still maintains the decoding procedure and search space concept in LTE-A systems. Terms — Physical downlink control channel (PDDCH), aggregation level, search space, control channel element, u ser equipment (UE).

Uneven clustering routing protocol based on dynamic partition for wireless sensor network

Abstract: To solve the "hot spots" problem caused by uneven load energy, a novel distributed clustering routing protocol was proposed. Its core is an uneven clustering routing protocol based on dynamic partition(UCDP). In UCDP, the entire network's energy consumption is balanced by dynamic partitioning, making the regions closer to the sink node with smaller nodes, which can preserve some energy for inter-region data forwarding. Considering the distance factor and residual energy factor for uneven clustering in each region, cluster-heads and region-heads work together in UCDP. Via the combination of single-hop and multi-hop, DBUP has established an optimal energy-balanced routing protocol. Simulation results show that UCDP has good stability, and significantly prolongs the network life.

Thermal Modeling and Analysis of Cloud Data Storage Systems

Abstract: An explosive increment of data and a variety of data analysis make it indispensable to lower power and cooling costs of cloud datacenters. To address this issue, we investigate the thermal impact of I/O access patterns on data storage systems. Firstly, we conduct some preliminary experiments to study the thermal behavior of a data storage node. The experimental results show that disks have ignorable thermal impacts as processors to outlet temperatures of storage nodes. We raise an approach to model the outlet temperature of a storage node. The thermal models generated by our approach gains a precision error less than 6%. Next, we investigate the thermal impact of data placement strategies on storage systems. We compare the cooling cost of storage systems governed by different data placement schemes. Our study shows that evenly distributing the data leads to highest outlet temperature for the sake of shortest execution time and energy efficiency. According to the energy consumption of various data placement schemes, we propose a thermal-ware energy-efficient data placement strategy. We further show that this work can be extended to analyze the cooling cost of data centers with massive storage capacity. Big data, which is composed of a collection of huge and complex data sets, has been positioned as must have commodity and resource in industry, government, and academia. Processing big data requires a large-scale storage system, which increases both power and cooling costs. In this study, we investigate the thermal behavior of real storage systems and their I/O access patterns, which offer a guideline of building energy-efficient cloud storage systems. The cooling consumption of data centers can be considerably reduced by using an efficient thermal management for storage systems. However, disk is not considered in traditional thermal models for data centers. In this paper, we investigate the thermal impact of hard disks and propose a thermal modeling approach for storage systems. In addition, we estimate the outlet temperature of a storage server by applying the proposed

Research on reconfigurable information communication basal network architecture

Abstract: Based on the thinking of network reconfiguration, the reconfigurable information communication basal network architecture was proposed, and then the network atomic capacity theory, polymorphic addressing and routing mechanism, network reconfiguration mechanism and the secure manageability and controllability mechanism were put forward respectively The architecture would provide a resolution for current and future applications with different quality of services, flexible and expansible function, universal inter-connection, heterogeneous convergence, manageability and controllability, which also supports the compatible evolution with current internet and is feasible to be implemented on a large scale

Survey of wireless channel measurement and characterization for high-speed railway scenarios

Abstract: The conducted measurement campaigns, domestic and overseas, were presented. Meanwhile, proposals and standard channel models from the international standardization organization were reviewed. The large-scale and small-scale fading characteristics of High-Speed Railway wireless channels were adequately compared, and it is found that the channel parameters depend on the propagation environment and the distance between the transmitter and receiver. Moreover, due to difficulties encountered in realistic channel measurements, theoretical channel characterization methods were analyzed. Finally, open research issues were presented.

A review on intelligent base stations cooperation management techniques for greener lte cellular networks

Abstract: —Energy efficiency in wireless networks has become the most compelling challenge for researchers, equipment vendors, and mobile operators not only to reduce operational costs but also to reduce the environmental effects and to make cellular networks more environmentally friendly. There have been many attempts to achieve appropriate solutions to this issue. In this paper, we provide an extensive overview of the intelligent cooperation management techniques (switching cell, cell zooming, heterogeneous networks, and mobile operator cooperation) that have been considered to save energy and we highlight the principles of the operation, energy savings, advantages, and shortcomings of each technique. We conclude this review with several open issues and potential research topics in this field.

The Security of Physical Layer in Cognitive Radio Networks

Abstract: —Cognitive Radio (CR) is a novel technology that promises to solve the lack of spectrum by allowing secondary users to use licensed band, so that they can coexist with primary users without causing interference to their communications. With the development of CR, extending to the level of network, cognitive radio networks (CRNs) emerge as the times require. Nowadays the operational aspects of CRN are being explored vigorously, and several potential security challenges for cognitive radio have gained lots of attention. In this paper, we explore the security issues on physical layer for cognitive radio networks. First, we give a brief overview of the CRNs, then we review several existing secure threats to the physical layer in CRNs and we propose a new kind of security problem. Next, we discuss the related countermeasures on how to defend against these attacks. Subsequently, we conduct an evaluation of these countermeasures, and make some future works for secure CRNs. At last, we make the conclusion.