Hindawi Publishing

Displaying 201-240 of 1675 results

  • White Papers // Dec 2013

    User Access Control and Authentication System for VoIP Service in Mobile communication environments

    VoIP, which is used to transmit voice data on the Internet, is being welcomed as a replacement for the PSTN. In VoIP, voice data are converted to IP data and transmitted in an ordinary IP network. As a result, it is less expensive than the ordinary telephone network and has...

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  • White Papers // Dec 2013

    Research on Load Balancing in Cloud Computing Based on Marketing Theory

    Though a cloud environment can create the appearance of an endless supply of computing resources, the computing resources are still limited from perspective of cloud management. As the key supporting technologies of future internet, load balancing algorithms and job allocations are main research problems in areas of resource management of...

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  • White Papers // Dec 2013

    Vulnerability Assessment of IPv6 Websites to SQL Injection and Other Application Level Attacks

    Given the proliferation of internet connected devices, IPv6 has been proposed to replace IPv4. Aside from providing a larger address space which can be assigned to internet enabled devices, it has been suggested that the IPv6 protocol offers increased security due to the fact that with the large number of...

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  • White Papers // Dec 2013

    Evolutionary Multiobjective Query Workload Optimization of Cloud Data Warehouses

    With the advent of Cloud databases, query optimizers need to find pareto-optimal set of solutions in terms of response time and monetary cost. The authors' novel approach minimizes both objectives by deploying alternative virtual resources and query plans making use of the virtual resource elasticity of the Cloud. They propose...

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  • White Papers // Nov 2013

    Formal Specification Based Automatic Test Generation for Embedded Network Systems

    Embedded systems have become increasingly connected and communicate with each other, forming large-scaled and complicated network systems. To make their design and testing more reliable and robust, this paper proposes a formal specification language called SENS and a SENS-based automatic test generation tool called TGSENS. The authors' approach is summarized...

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  • White Papers // Nov 2013

    Enhanced ID-Based Authentication Scheme Using OTPin Smart Grid AMI Environment

    In this paper, the authors analyze the vulnerabilities of KL scheme which is an ID-based authentication scheme for AMI network, and propose two kinds of authentication schemes which satisfy forward secrecy as well as security requirements introduced in the previous works. In this paper, they use MDMS which is the...

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  • White Papers // Nov 2013

    Secure Beamforming via Amplify-and-Forward Relays in Machine-to-Machine Communications

    The authors consider the collaborative use of amplify-and-forward relays to forma beamforming system and provide physical layer security for a wireless Machine-To-Machine (M2M) communication network. They investigate two objectives: the achievable secrecy rate maximization subject to the relay power constraint and the relay transmit power minimization under a secrecy rate...

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  • White Papers // Nov 2013

    Introducing WebSocket-Based Real-Time Monitoring System for Remote Intelligent Buildings

    Today, Wireless Sensor Networks (WSNs) in electronic engineering are used in the monitoring of remote intelligent buildings, and the need for emerging web 3.0 is becoming more and more in every aspect of electronic engineering. However, the key challenges of monitoring are the monitoring approaches and storage models of huge...

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  • White Papers // Nov 2013

    Trusted Computing Strengthens Cloud Authentication

    Cloud computing is a new generation of technology which is designed to provide the commercial necessities, solve the IT management issues as well as running the appropriate applications. Another entry on the list of cloud functions which has been handled internally is Identity Access Management (IAM). Companies encounter IAM as...

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  • White Papers // Nov 2013

    Selective Cooperative Transmission in Ad Hoc Networks with Directional Antennas

    In this paper, the authors present a Selective Cooperative Transmission scheme (abbreviated SCT) for ad hoc network with directional antennas that leverages the benefits of directional-only antenna approach and cooperative communication. The main feature of SCT is its adaptability to the channel condition in the network. In other words, when...

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  • White Papers // Nov 2013

    Efficient Resources Provisioning Based on Load Forecasting in Cloud

    Cloud providers should ensure QoS while maximizing resources utilization. One optimal strategy is to timely allocate resources in a fine-grained mode according to application's actual resources demand. The necessary precondition of this strategy is obtaining future load information in advance. The authors propose a multi-step-ahead load forecasting method, KSwSVR, based...

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  • White Papers // Oct 2013

    An Embedded Cloud Design for Internet-of-Things

    Internet-of-Things (IoT) consists of interconnected heterogeneous devices that ubiquitously interact with physical world. The devices are often resource constrained in terms of energy, computation, and communication resources. Distributing processing between these heterogeneous devices could yield to better performance and sharing, and extending resources of the devices could yield to more...

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  • White Papers // Oct 2013

    SSE: A Secure Searchable Encryption Scheme for Urban Sensing and Querying

    With the distributed sensors that are deployed to monitor the urban environment in smart cities, the sensed data are overwhelming and beyond the scope of the Wireless Sensor Networks (WSNs) capability. Due to the communication range limits of the sensors, most of these data will be outsourced and stored on...

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  • White Papers // Oct 2013

    A Novel Authentication Scheme for V2I Communication Based on WAVE Unicast Services

    One of the most challenging issues in vehicular network designs is security matter. Particularly, there have been several potential attacks (e.g., message alteration, eavesdropping, privacy violation, and replay) on Vehicle To Infrastructure (V2I) communication. Most previous studies have based on Public Key Infrastructure (PKI) and authentication in broadcast services. By...

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  • White Papers // Oct 2013

    A Novel Web Classification Algorithm Using Fuzzy Weighted Association Rules

    In associative classification method, the rules generated from association rule mining are converted into classification rules. The concept of association rule mining can be extended in web mining environment to find associations between web pages visited together by the internet users in their browsing sessions. The weighted fuzzy association rule...

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  • White Papers // Oct 2013

    On the Anonymity of Identity-Based Encryption

    Anonymity of Identity-Based Encryption (IBE) means that given a cipher-text, one cannot distinguish the target identity from a random identity. In this paper, the authors thoroughly discuss the anonymity of IBE systems. They found that the current definition of anonymity is obscure to describe some IBE systems, such as Gentry...

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  • White Papers // Oct 2013

    A Karaoke System with Real-Time Media Merging and Sharing Functions for a Cloud-Computing-Integrated Mobile Device

    Mobile devices such as Personal Digital Assistants (PDAs), Smartphones, and tablets have increased in popularity and are extremely efficient for work-related, social, and entertainment uses. Popular entertainment services have also attracted substantial attention. Thus, relevant industries have exerted considerable efforts in establishing a method by which mobile devices can be...

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  • White Papers // Oct 2013

    Circuit Implementation, Operation, and Simulation of Multivalued Nonvolatile Static Random Access Memory Using a Resistivity Change Device

    The authors proposed and computationally analyzed a multi-valued, nonvolatile SRAM using a ReRAM. Two reference resistors and a programmable resistor are connected to the storage nodes of a standard SRAM cell. The proposed 9T3R MNV-SRAM cell can store 2 bits of memory. In the storing operation, the recall operation and...

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  • White Papers // Oct 2013

    Enterprise Information Security Management Based on Context-Aware RBAC and Communication Monitoring Technology

    Now-a-days, in the workplace, information technology has an enormous influence on many enterprises. Information technology has an enormous influence in many enterprises. Computers have not only become important devices that people rely on in their daily lives and work, but have also become essential tools for enterprises. More and more...

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  • White Papers // Oct 2013

    Hybrid MAC Scheme for Vehicular Communications

    Vehicular communications have been creating new applications in Intelligent Transportation Systems (ITS) areas by converging Information and Communication Technology (ICT) with automobile and road industries. In this paper, the authors introduce hybrid MAC scheme for vehicular communications which enhances the performance of IEEE 802.11p based communication system. The proposed MAC...

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  • White Papers // Oct 2013

    Reputation Revision Method for Selecting Cloud Services Based on Prior Knowledge and a Market Mechanism

    The trust levels of cloud services should be evaluated to ensure their reliability. The effectiveness of these evaluations has major effects on user satisfaction, which is increasingly important. However, it is difficult to provide objective evaluations in open and dynamic environments because of the possibilities of malicious evaluations, individual preferences,...

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  • White Papers // Oct 2013

    A Novel Cloud Computing Algorithm of Security and Privacy

    Cloud computing provides service of several different service types, namely, Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS). The emergence of cloud computing has simplified the flow of large-scale deployment distributed system of software suppliers; when issuing respective application programs in a...

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  • White Papers // Oct 2013

    Cloud Service Selection Using Multi-Criteria Decision Analysis

    Cloud Computing (CC) has recently been receiving tremendous attention from the IT industry and academic researchers. CC leverages its unique services to cloud customers in a pay-as-you-go, anytime, anywhere manner. Cloud services provide dynamically scalable services through the Internet on demand. Therefore, service provisioning plays a key role in CC....

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  • White Papers // Oct 2013

    Empirical Analysis of Server Consolidation and Desktop Virtualization in Cloud Computing

    Physical server transited to Virtual Server Infrastructure (VSI) and desktop device to Virtual Desktop Infrastructure (VDI) have the crucial problems of server consolidation, virtualization performance, virtual machine density, Total Cost of Ownership (TCO), and Return On Investments (ROI). Besides, how to appropriately choose hypervisor for the desired server/desktop virtualization is...

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  • White Papers // Oct 2013

    Efficient Cluster Head Selection Algorithm for MANET

    In Mobile Ad hoc NETwork (MANET) cluster head selection is considered a gigantic challenge. In wireless sensor network LEACH protocol can be used to select cluster head on the bases of energy, but it is still a dispute in mobile ad hoc networks and especially when nodes are itinerant. In...

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  • White Papers // Oct 2013

    Location Estimation Using Space-Time Signal Processing in RFID Wireless Sensor Networks

    The authors consider Real-Time Locating Systems (RTLS) consisting of Radio Frequency IDentification (RFID) tags and multi-antenna readers to propose a novel location estimation algorithm based on the concept of space-time signature matching for multipath environments. In contrast to previous fingerprint-based approaches that rely on Received Signal Strength (RSS) information only,...

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  • White Papers // Oct 2013

    Secure and Efficient Control Transfer for IoT Devices

    The prevalence of Internet of Things (IoT) requires flexible and fine-grained controls over the IoT devices. Existing works rely on specific controllers or programs to remotely control IoT devices, which is inefficient to support intelligent control in IoT environments. In contrast, utilizing a common portal device, for example, smart phone,...

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  • White Papers // Oct 2013

    Privacy Protection Based Secure Data Transaction Protocol for Smart Sensor Meter in Smart Grid

    A smart grid is a data communications network integrated with an electrical grid that collects and analyzes near-real-time data on power transmission, distribution, and consumption. Currently, smart grid systems are considered to be necessary for improving the monitoring and control of a power distribution infrastructure. Using distributed measurement architecture, it...

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  • White Papers // Sep 2013

    Intrusion Detection Systems Based on Artificial Intelligence Techniques in Wireless Sensor Networks

    Wireless Sensor Networks (WSNs) are distributed in nature where sensor nodes operate independently without any centralized authority. Intrusion Detection System (IDS) is regarded as the second line of defense against network anomalies and threats. IDS play an important role in network security. There are many techniques which are used to...

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  • White Papers // Sep 2013

    FPGA Fault Tolerant Arithmetic Logic: A Case Study Using Parallel-Prefix Adders

    In this paper, the authors examine fault tolerant adder designs implemented on FPGAs which are inspired by the methods of modular redundancy, roving, and gradual degradation. A parallel-prefix adder based upon the Kogge-Stone (KS) configuration is compared with the simple Ripple Carry Adder (RCA) design. The Kogge-Stone (KS) design utilizes...

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  • White Papers // Sep 2013

    Systems Thinking Safety Analysis: Nuclear Security Assessment of Physical Protection System in Nuclear Power Plants

    The dynamical quantification is done in the security of Nuclear Power Plants (NPPs). The time delay is important to the security of the NPPs. How the defense against possible terror attack reacts could be analyzed by some aspects by several external impacts. The political, social, and technological aspects could be...

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  • White Papers // Sep 2013

    Detection and Countermeasure of Node Misbehaviour in Clustered Wireless Sensor Network

    Wireless sensor networks are widely used in many applications like battlefield monitoring, environment monitoring, and so forth. In all of these applications the cooperation among various sensor nodes is needed to forward the data packets to the base station. However, it expends the various resources of a sensor node such...

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  • White Papers // Sep 2013

    Balancing Energy Consumption in Clustered Wireless Sensor Networks

    Clustering in wireless sensor networks is an efficient way to structure and organize the network. It aims at identifying a subset of nodes within the network and binding it to a leader (i.e., cluster head). The leader becomes in charge of specific additional tasks like gathering data from all nodes...

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  • White Papers // Sep 2013

    A Secure Implementation of a Symmetric Encryption Algorithm in White-Box Attack Contexts

    In a white-box context, an adversary has total visibility of the implementation of the cryptosystem and full control over its execution platform. As a countermeasure against the threat of key compromise in this context, a new secure implementation of the symmetric encryption algorithm SHARK is proposed. The general approach is...

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  • White Papers // Sep 2013

    Secure and Efficient Anonymous Authentication Scheme in Global Mobility Networks

    In this paper, the authors examined the previous schemes and security vulnerabilities of the previous schemes. Lee et al.'s and Wu et al.'s scheme was vulnerable to replay attack, cannot achieved perfect forward secrecy, cannot provided anonymity. And Mun et al.'s scheme was vulnerable to replay attack and man-in-the-middle attack,...

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  • White Papers // Sep 2013

    Design of an Evolutionary Approach for Intrusion Detection

    A novel evolutionary approach is proposed for effective intrusion detection based on benchmark datasets. The proposed approach can generate a pool of non-inferior individual solutions and ensemble solutions thereof. The generated ensembles can be used to detect the intrusions accurately. For intrusion detection problem, the proposed approach could consider conflicting...

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  • White Papers // Sep 2013

    An Efficient Processing of Join Queries for Sensor Networks Using Column-Oriented Databases

    Recently, the sensor network area is gaining attention both in the industry and academia. Many applications of sensor network such as vehicle tracking and environmental monitoring require joining sensor data scattered over the network. The main performance criterion for queries in a sensor network is to minimize the battery power...

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  • White Papers // Sep 2013

    An Efficient Cluster Authentication Scheme Based on VANET Environment in M2M Application

    Wireless and mobile sensor network technologies in M2M (Machine-To-Machine) are rapidly applied to the people real life. Thus, in near future, advanced wireless and mobile sensor network in M2M application will be major key factor of the future generation convergence network which is based on the state of the application....

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  • White Papers // Sep 2013

    Framework for Secure Wireless Communication in Wireless Sensor Networks

    With large-scale and rapid development in Wireless Sensor Networks (WSNs), there is great demand to adopt security mechanisms for secure wireless communication. WSNs have many fields of applications that are playing an essential role in increasing productivity and reducing cost. The restricted and constrained nature of sensors along with potentially...

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  • White Papers // Sep 2013

    An Efficient WSN Simulator for GPU-Based Node Performance

    In wireless sensor network, when these sensors are wrongly placed in an observation region, they can quickly run out of batteries or be disconnected. These incidents may result in huge losses in terms of sensing data from numerous sensors and their costs. For this reason, a number of simulators have...

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  • White Papers // Jun 2010

    Analysis and Construction of Full-Diversity Joint Network-LDPC Codes for Cooperative Communications

    Transmit diversity is necessary in harsh environments to reduce the required transmit power for achieving a given error performance at a certain transmission rate. In networks, cooperative communication is a well-known technique to yield transmit diversity and network coding can increase the spectral efficiency. These two techniques can be combined...

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  • White Papers // Jul 2010

    Adaptive Power Allocation in Wireless Sensor Networks with Spatially Correlated Data and Analog Modulation: Perfect and Imperfect CSI

    The authors address the problem of power allocation in a wireless sensor network where distributed sensors amplify and forward their partial and noisy observations of a Gaussian random source to a remote Fusion Center (FC). The FC reconstructs the source based on Linear Minimum Mean-Squared Error (LMMSE) estimation rule. Motivated...

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  • White Papers // Jul 2010

    Size-Based and Direction-Based TCP Fairness Issues in IEEE 802.11 WLANs

    Cross-layer interaction of Distributed Coordination Function (DCF) of 802.11 MAC protocol and TCP transport protocol leads to two types of unfairness. In a mixed traffic scenario, short-lived TCP flows suffer from poor performance compared to the aggressive long-lived flows. Since the main source of Internet traffic is small file web...

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  • White Papers // Jul 2010

    Joint Sensing Period and Transmission Time Optimization for Energy-Constrained Cognitive Radios

    Under interference constraint and energy consumption constraint, to maximize the channel utilization, an Opportunistic Spectrum Access (OSA) strategy for a slotted Secondary User (SU) overlaying an unslotted ON/OFF Continuous Time Markov Chain (CTMC) modeled primary network is proposed. The OSA strategy is investigated via a cross-layer optimization approach, with joint...

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  • White Papers // May 2010

    Reducing the MAC Latency for IEEE 802.11 Vehicular Internet Access

    In an intermittently connected environment, access points are sparsely distributed throughout an area. As mobile users travel along the roadway, they can opportunistically connect, albeit temporarily, to roadside 802.11 (Wi-Fi) APs for Internet access. Networking characteristics of vehicular Internet access in an intermittently connected environment face numerous challenges, such as...

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  • White Papers // Feb 2010

    Opportunistic Relay Selection with Cooperative Macro Diversity

    The authors apply a fully opportunistic relay selection scheme to study cooperative diversity in a semianalytical manner. In their framework, idle Mobile Stations (MSs) are capable of being used as Relay Stations (RSs) and no relaying is required if the direct path is strong. Their relay selection scheme is fully...

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  • White Papers // Feb 2010

    Quality-Aware SCTP in Wireless Networks

    SCTP (Stream Control Transmission Protocol) is a new transport layer protocol that was published as RFC2960 by IETF (the Internet Engineering Task Force) in October 2000 and amended in RFC4960 in September 2007. SCTP provides reliable ordered and unordered transport services. The congestion control and flow control mechanisms for SCTP...

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  • White Papers // Aug 2009

    A Potential Transmitter Architecture for Future Generation Green Wireless Base Station

    Current radio frequency power amplifiers in 3G base stations have very high power consumption leading to a hefty cost and negative environmental impact. In this paper, the authors propose a potential architecture design for future wireless base station. Issues associated with components of the architecture are investigated. The all-digital transmitter...

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  • White Papers // Jun 2009

    Secrecy Capacity of a Class of Broadcast Channels with an Eavesdropper

    The authors study the security of communication between a single transmitter and many receivers in the presence of an eavesdropper for several special classes of broadcast channels. As the first model, they consider the degraded multireceiver wiretap channel where the legitimate receivers exhibit a degradedness order while the eavesdropper is...

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  • White Papers // Dec 2010

    Cross-Layer Design of the Inter-RAT Handover between UMTS and WiMAX

    In future mobile networks, different radio access technologies will have to coexist. IEEE 802.21 MIH (Media-Independent Handover) provides primitive mechanisms that ease the implementation of a seamless vertical handover (inter-RAT handover) between different radio access technologies. However, it does not specify any handover execution mechanism. The first objective of this...

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  • White Papers // Nov 2010

    Effects of Channel Estimation on Multiuser Virtual MIMO-OFDMA Relay-Based Networks

    A practical multiuser cooperative transmission scheme denoted as Virtual Maximum Ratio Transmission (VMRT) for Multiple-Input Multiple-Output-Orthogonal Frequency Division Multiple Access (MIMO-OFDMA) relay-based networks is proposed and evaluated in the presence of a realistic channel estimation algorithm and using Low-Density Parity-Check (LDPC) codes. It is shown that this scheme is robust...

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  • White Papers // Nov 2010

    EDDK: Energy-Efficient Distributed Deterministic Key Management for Wireless Sensor Networks

    Energy efficiency is an essential requirement for wireless sensor networks while security must also be ensured for mission-critical applications. In this paper, the authors present an Energy-efficient Distributed Deterministic Key management scheme (EDDK) for resource-constrained wireless sensor networks. EDDK mainly focuses on the establishment and maintenance of the pairwise keys...

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  • White Papers // Jan 2011

    Full Rate Network Coding via Nesting Modulation Constellations

    Network coding is an effective method to improving relay efficiency, by reducing the number of transmissions required to deliver data from source(s) to destination(s). However, its performance may be greatly degraded by rate mismatch, which is seldom touched in previous works and remains a challenge. In this paper, the authors...

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  • White Papers // Jan 2011

    Power Allocation between Pilot and Data Symbols for MIMO Systems with MMSE Detection under MMSE Channel Estimation

    For Multiple-Input Multiple-Output (MIMO) wireless communication system with Minimum Mean Square Error (MMSE) detection, a new scheme of power allocation between pilot and data symbols is investigated under MMSE channel estimation in this paper. First, the authors propose a novel soft-output MMSE MIMO detector by taking into consideration the channel...

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  • White Papers // Sep 2009

    Intercarrier Interference in OFDM: A General Model for Transmissions in Mobile Environments with Imperfect Synchronization

    InterCarrier Interference (ICI) is an impairment well known to degrade performance of Orthogonal Frequency Division Multiplexing (OFDM) transmissions. It arises from Carrier Frequency Offsets (CFOs), from the Doppler spread due to channel time-variation and, to a lesser extent, from Sampling Frequency Offsets (SFOs). Literature reports several models of ICI due...

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  • White Papers // Jan 2011

    Emergency Handling for MAC Protocol in Human Body Communication

    The Human Body Communication (HBC) is a technology that enables short range data communication using the human body as a medium, like an electrical wire. Thus it removes the need for a traditional antenna. HBC may be used as a type of data communication in Body Area Network (BAN), while...

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  • White Papers // Feb 2010

    ABCDecision: A Simulation Platform for Access Selection Algorithms in Heterogeneous Wireless Networks

    The authors present a simulation platform for access selection algorithms in heterogeneous wireless networks, called "ABCDecision." The simulator implements the different parts of an Always Best Connected (ABC) system, including Access Technology Selector (ATS), Radio Access Networks (RANs), and users. After describing the architecture of the simulator, they show an...

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  • White Papers // Jan 2011

    Iterative Fusion of Distributed Decisions over the Gaussian Multiple-Access Channel Using Concatenated BCH-LDGM Codes

    This paper focuses on the data fusion scenario where N nodes sense and transmit the data generated by a source S to a common destination, which estimates the original information from S more accurately than in the case of a single sensor. This paper joins the upsurge of research interest...

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  • White Papers // Jan 2010

    Performance Analysis of Multibranch Dual-Hop Nonregenerative Relay Systems with EGC in Nakagami-m Channels

    The end-to-end performance of multibranch dual-hop wireless communication systems with nonregenerative relays and Equal Gain Combiner (EGC) at the destination over independent Nakagami-m fading channels is studied. The authors present new closed form expressions for Probability Distribution Function (PDF) and Cumulative Distribution Function (CDF) of end-to-end Signal to Noise Ratio...

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  • White Papers // Dec 2009

    Spreading Code Assignment Strategies for MIMO-CDMA Systems Operating in Frequency-Selective Channels

    Code Division Multiple Access (CDMA) and Multiple Input Multiple Output- (MIMO-) CDMA systems suffer from Multiple Access Interference (MAI) which limits the spectral efficiency of these systems. By making these systems more power efficient, the authors can increase the overall spectral efficiency. This can be achieved through the use of...

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  • White Papers // Mar 2010

    A Precoded OFDMA System with User Cooperation

    A new cooperative scheme for a two-user Orthogonal Frequency Division Multiple Access (OFDMA) uplink communication scenario is proposed. Each user is equipped with one transmit/receive antenna. Before transmission, inter-block linear precoding is introduced to pairs of blocks. The cooperative transmission is implemented in cycles of three time slots. During each...

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  • White Papers // Jan 2010

    Hybrid Wired/Wireless PROFIBUS Architectures: Performance Study Based on Simulation Models

    The problem of providing a hybrid wired/wireless communications for factory automation systems is still an open issue, notwithstanding the fact that already there are some solutions. This paper describes the role of simulation tools on the validation and performance analysis of two wireless extensions for the PROFIBUS protocol. In one...

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  • White Papers // Jan 2011

    Performance Analysis of Ad Hoc Dispersed Spectrum Cognitive Radio Networks Over Fading Channels

    Cognitive radio systems can utilize dispersed spectrum, and thus such approach is known as dispersed spectrum cognitive radio systems. In this paper, the authors first provide the performance analysis of such systems over fading channels. They derive the average symbol error probability of dispersed spectrum cognitive radio systems for two...

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  • White Papers // Mar 2010

    Using Model Checking for Analyzing Distributed Power Control Problems

    Model Checking (MC) is a formal verification technique which has been known and still knows a resounding success in the computer science community. Realizing that the distributed Power Control (PC) problem can be modeled by a timed game between a given transmitter and its environment, the authors wanted to know...

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  • White Papers // Oct 2009

    A MIMO-OFDM Testbed

    The design, implementation, and test of a real-time flexible 2?2 (Multiple Input-Multiple Output-Orthogonal Frequency Division Multiplexing) MIMO-OFDM IEEE 802.16 prototype are presented. For the design, a channel measurement campaign on the 3.5GHz band has been carried out, focusing on outdoor-indoor scenarios. The analysis of measured channels showed that higher capacity...

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  • White Papers // Jan 2010

    A Propagation Environment Modeling in Foliage

    Foliage clutter, which can be very large and mask targets in backscattered signals, is a crucial factor that degrades the performance of target detection, tracking, and recognition. Previous literature has intensively investigated land clutter and sea clutter, whereas foliage clutter is still an open-research area. In this paper, the authors...

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  • White Papers // Apr 2010

    Multiagent Q-Learning for Aloha-Like Spectrum Access in Cognitive Radio Systems

    An Aloha-like spectrum access scheme without negotiation is considered for multiuser and multichannel cognitive radio systems. To avoid collisions incurred by the lack of coordination, each secondary user learns how to select channels according to its experience. MultiAgent Reinforcement Leaning (MARL) is applied for the secondary users to learn good...

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  • White Papers // Aug 2010

    Energy-Efficient Reservation-Based Medium Access Control Protocol for Wireless Sensor Networks

    In Wireless Sensor Networks (WSNs), a robust and energy-efficient Medium Access Control (MAC) protocol is required for high energy efficiency in harsh operating conditions, where node and link failures are common. This paper presents the design of a novel MAC protocol for low-power WSNs. The developed MAC protocol minimizes the...

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  • White Papers // Jan 2011

    Fast Signal Recovery in the Presence of Mutual Coupling Based on New 2-D Direct Data Domain Approach

    Adaptive antenna arrays are strongly affected by the existence of Mutual Coupling (MC) effect between antenna elements; thus, if the effects of MCare ignored, the system performance will not be accurate. Research into compensation for the MC has been mainly based on the idea of using open circuit voltages, firstly...

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  • White Papers // Jul 2009

    Power Allocation Strategies for Distributed Space-Time Codes in Amplify-and-Forward Mode

    The authors consider a wireless relay network with Rayleigh fading channels and apply Distributed Space-Time Coding (DSTC) in Amplify-and-Forward (AF) mode. It is assumed that the relays have statistical Channel State Information (CSI) of the local source-relay channels, while the destination has full instantaneous CSI of the channels. It turns...

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  • White Papers // Jul 2010

    Approximate Minimum Bit Error Rate Equalization for Fading Channels

    A novel channel equalizer algorithm is introduced for wireless communication systems to combat channel distortions resulting from multipath propagation. The novel algorithm is based on minimizing the Bit Error Rate (BER) using a fast approximation of its gradient with respect to the equalizer coefficients. This approximation is obtained by estimating...

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  • White Papers // Apr 2011

    Peer-to-Peer Jini for Truly Service-Oriented WSNs

    In the past, wireless sensor networks emerged and so did some state-of-the-art applications that ran above them. Most of those applications followed the centralized model and were mainly focused on environmental data gathering, where sensor nodes sensed data from the environment to be sent to an external data server for...

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  • White Papers // Nov 2009

    Cooperative Detection for Primary User in Cognitive Radio Networks

    The authors propose two novel cooperative detection schemes based on the AF (Amplify and Forward) and DF (Decode and Forward) protocols to achieve spatial diversity gains for cognitive radio networks, which are referred to as the AF-CDS, (AF-based Cooperative Detection Scheme) and DF-CDS (DF-based Cooperative Detection Scheme), respectively. Closed-form expressions...

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  • White Papers // Dec 2009

    Experimental Data Collection and Performance Analysis of Outdoor UWB Positioning System Under Static and Mobile Conditions

    A wide variety of semiautonomous systems are emerging in construction, defense, and agricultural applications. A UWB positioning system shows promise in improving navigational capabilities and safety of operations for these systems. This paper describes an outdoor UWB positioning system used to measure the position of the operators of a semiautonomous...

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  • White Papers // May 2009

    Relay Architectures for 3GPP LTE-Advanced

    The Third Generation Partnership Project's Long Term Evolution-Advanced is considering relaying for cost-effective throughput enhancement and coverage extension. While analog repeaters have been used to enhance coverage in commercial cellular networks, the use of more sophisticated fixed relays is relatively new. The main challenge faced by relay deployments in cellular...

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  • White Papers // Nov 2009

    Development of a Testbed for Wireless Underground Sensor Networks

    Wireless Underground Sensor Networks (WUSNs) constitute one of the promising application areas of the recently developed wireless sensor networking techniques. WUSN is a specialized kind of Wireless Sensor Network (WSN) that mainly focuses on the use of sensors that communicate through soil. Recent models for the wireless underground communication channel...

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  • White Papers // Jan 2010

    Cross-Layer Measurement on an IEEE 802.11g Wireless Network Supporting MPEG-2 Video Streaming Applications in the Presence of Interference

    The performance of wireless local area networks supporting video streaming applications, based on MPEG-2 video codec, in the presence of interference is here dealt with. IEEE 802.11g standard wireless networks, that do not support QoS in according with IEEE 802.11e standard, are, in particular, accounted for and Bluetooth signals, additive...

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  • White Papers // Feb 2011

    A Comprehensive Approach to Power Management in Embedded Systems

    Power management is addressed in the context of embedded systems from energy-aware design to energy-efficient implementation. A set of mechanisms specifically conceived for this scenario is proposed, including a power management API defined at the level of user-visible system components, the infrastructure necessary to implement that API (namely, battery monitoring,...

    Provided By Hindawi Publishing

  • White Papers // Jun 2010

    Joint NC-ARQ and AMC for QoS-Guaranteed Mobile Multicast

    In mobile multicast transmissions, the receiver with the worst instantaneous channel condition limits the transmission data rate under the desired Quality-of-Service (QoS) constraints. If Automatic Repeat reQuest (ARQ) schemes are applied, the selection of Adaptive Modulation and Coding (AMC) mode will not necessarily be limited by the worst channel anymore,...

    Provided By Hindawi Publishing

  • White Papers // Jul 2010

    Distributed KDC-Based Random Pairwise Key Establishment in Wireless Sensor Networks

    Key management is a core mechanism to provide secure and reliable communications in Wireless Sensor Networks (WSNs). In large-scale WSNs, due to the resource constraint on sensor nodes, it is still an extremely challenging task to achieve good performance in terms of high network connectivity and strong resilience against sensor...

    Provided By Hindawi Publishing