RWSoftware

Displaying 1-40 of 268 results

  • White Papers // Nov 2014

    Component-Based Specification of Software Product Line Architecture

    Software product lines have known an increasing use over the last years, taking advantage from the important benefits they may bring to software development in terms of time, cost and effort. However, product line approaches remain immature owing to the fact that they still base on traditional design concepts of...

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  • White Papers // Nov 2014

    Dealing with Deviations on Software Process Enactment : Comparison Framework

    Software development is a collective and complex task carried out through the cooperation of human agents and automated tools, this interaction defines the software process. PSEE (Process-centered Software Engineering Environment) are environments designed to support the creation and exploitation of software process models that define the expected behaviors of process...

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  • White Papers // Nov 2014

    Modeling Channel Allocation via BRS: Case of WMNs

    Wireless Mesh Networks (WMNs), is an emerging wireless technology which attracts more and more attention of service providers and enterprises. The main advantage of this new class of network is to offer a flexible and economical way to expand internet access. Their major concern is to improve the flow and...

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  • White Papers // Nov 2014

    Generating FoCaLiZe Specifications from UML Models

    UML is the defacto standard language to graphically describe systems in an object oriented way. Once an application has been modeled, Model Driven Architecture (MDA) techniques can be applied to generate code from such models. Because UML lacks formal basis to analyze and check model consistency, it is pertinent to...

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  • White Papers // Nov 2014

    BiCloud-2M: A Combined Bigraph Maude-based Tool for Cloud Specification and Analysis

    Service availability is a challenging issue in cloud computing. It implies continuous reconfiguration of cloud architecture by adding or removing different resources (virtual machines and services) to ensure the suited quality of service. Thus a main goal in cloud systems design is to model and analyze cloud architecture and its...

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  • White Papers // Nov 2014

    A Highly Adaptive Leader Election Algorithm for Mobile Ad Hoc Networks

    Leader election has been identified as a basic building block in distributed computing. MANETs are distinct from traditional distributed systems as they are dynamic and self-organizing networks because of their dynamic wireless link formation and removal, network partitioning and disconnections, limited bandwidth and energy and highly variable message delay. These...

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  • White Papers // Nov 2014

    Software Component Quality Evaluation

    Component-Based Software Engineering (CBSE) provides for developers the ability to easily reuse and assemble software entities to build complex software. It is based on the composition of prefabricated software entities called components. In this paper, the selection step is very important. It consists of searching and selecting appropriate software components...

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  • White Papers // Nov 2014

    A New Distributed Anonymization Protocol to Satisfy Multiple Data Provider's Privacy Requirements

    Privacy and security concerns are among the main obstacles facing the widespread adoption of this new technology. Data anonymization makes data worthless to anyone except the owner of the data. It is one of the methods for transforming the data in such a way that it prevents identification of key...

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  • White Papers // Nov 2014

    Ontology-Driven and Community-Based Framework for Services Description and Selection of Composite Services

    In this paper, the authors propose OWL DL ontology for web service description which aims at automating selection of composite web services. In this ontology, they identify communities as a mean to organize web services for a given shared domain. They relate concepts of community, service's functionality (atomic abstract service...

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  • White Papers // Nov 2014

    Specifing and Verifing Aspect-Oriented Systems in Rewriting Logic

    Aspect-Oriented (AO) systems have to deal with an important problem which is the management of aspect interaction. In this paper, the authors introduce a first tool, known as AO-Maude, which is based on Maude language for the specification and the verification of the AO systems. The proposed tool relies on...

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  • White Papers // Nov 2014

    A Multi-Objective Hybrid Particle Swarm Optimization-Based Service Identification

    Service identification step is a basic requirement for a detailed design and implementation of services in a Service Oriented Architecture (SOA). Existing methods for service identification ignore the automation capability while providing human based prescriptive guidelines, which mostly are not applicable at enterprise scales. In this paper, the authors propose...

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  • White Papers // Nov 2014

    Formal Specification of Multi-Agent System Architecture

    Multi-Agent Systems (MAS) are an emerging paradigm that has high potentials for developing distributed, open and concurrent complex systems. These systems often need to operate in dynamic environments and face the challenges of handling continuously changing requirements. These aspects increase the complexity of designing MAS. To handle the complexity and...

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  • White Papers // Nov 2014

    K-Maude Definition of Dynamic Software Architecture

    One of the complex issues in developing architectural models of software systems is the capturing of architectures dynamics, i.e., systems for which composition of interacting components, changes at run time. In this paper, the authors argue that it is possible and valuable to provide a Dynamic Software Architecture Meta-model (DySAM)...

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  • White Papers // Nov 2014

    The Wi-STARK Architecture for Resilient Real-Time Wireless Communications

    Networking communications play an important role to secure a dependable and timely operation of distributed and real-time embedded system applications; however, an effective real-time support is not yet properly addressed in the wireless realm. This paper presents Wi-STARK, a novel architecture for resilient and real-time wireless communications within a one-hop...

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  • White Papers // Nov 2014

    Constant Bandwidth Server Revisited

    The Constant Bandwidth Server (CBS) is an algorithm for providing temporal protection and real-time guarantees to real-time sporadic tasks. Recently, an implementation of this algorithm called SCHED-DEADLINE has been included in the Linux kernel. Therefore, the CBS algorithm is now used to serve more generic tasks than do not obey...

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  • White Papers // Nov 2014

    Validation of a Security Metamodel for Development of Cloud Applications

    Development of secure cloud applications requires a supportive approach that should also enable software assessment and certification by different mechanisms. These can assure by independent means that the required security is present. In this paper, the authors present a Core Security Meta-model (CSM) that is the director of a security...

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  • White Papers // Nov 2014

    On Metamodel Superstructures Employing UML Generalization Features

    The authors employ UML generalization features in order to describe multi-level meta-models and their connections. The basic idea is to represent several meta-model levels in one UML and OCL model and to connect the meta-models with (what they call) a superstructure. The advantage of having various levels in one model...

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  • White Papers // Oct 2014

    Software Analytics for MDE Communities

    The MDE research community has grown significantly in size and maturity in the last decade. During these years, a plethora of languages and tools has been proposed to address different challenges of the MDE approach to software development. As the community continues to broaden its expertise, it is worthwhile to...

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  • White Papers // Oct 2014

    Energy Efficiency Embedded Service Lifecycle: Towards an Energy Efficient Cloud Computing Architecture

    Cloud computing aims to streamline the on-demand provisioning of software, hardware, and data to provide flexibility and agility, and economies of scale in IT resource management. The paper argues the need to provide novel methods and tools to support software developers aiming to optimize energy efficiency and minimize the carbon...

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  • White Papers // Oct 2014

    Privacy-Preserving Indoor Localization

    Upcoming Wi-Fi-based localization systems for indoor environments face a conflict of privacy interests: server-side localization violates location privacy of the users, while localization on the user's device forces the localization provider to disclose the details of the system, e.g., sophisticated classification models. The authors show how secure two-party computation can...

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  • White Papers // Oct 2014

    Integrating Run-Time Observations and Design Component Models for Cloud System Analysis

    Run-time models have been proven beneficial in the past for predicting upcoming quality flaws in cloud applications. Observation approaches relate measurements to executed code whereas prediction models oriented towards design components are commonly applied to reflect reconfigurations in the cloud. Levels of abstraction differ between code observations and these prediction...

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  • White Papers // Oct 2014

    Eco-Reports in Clouds

    In this paper, the authors discuss the issues arising from the need of presenting to the user information about the environmental impact of their applications in a cloud environment. Several aspects have to be considered: to make aware the users of the energy consumption and environmental impact of their applications,...

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  • White Papers // Oct 2014

    Eco-Efficient Cloud Resource Monitoring and Analysis

    In this paper, the authors present an enhanced monitoring approach considering the infrastructure of providers' sites and the Virtual Machines (VMs) hosted on physical nodes. It considers the GAMES and the OPTIMIS projects that were both developing methods for energy-aware resource usage. This paper presents an approach for monitoring cloud...

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  • White Papers // Oct 2014

    On Developing Open Source MDE Tools: Our Eclipse Stories and Lessons Learned

    Tool development has always been a fundamental activity of software engineering. Now-a-days, open source is changing the way this is done in many organizations. Traditional ways of doing things are progressively enhanced or even sometimes replaced by new organizational schemes, benefiting as much as possible from the properties of Open...

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  • White Papers // Oct 2014

    On Static and Dynamic Analysis of UML and OCL Transformation Models

    This contribution discusses model transformations in the form of transformation models that connect a source and a target meta-model. The transformation model is statically analyzed within a UML and OCL tool by giving each constraint an individual representation in the underlying class diagram by highlighting the employed model elements. The...

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  • White Papers // Oct 2014

    HybridRank : A Hybrid Content-Based Approach to Mobile Game Recommendations

    The massive number of mobile games available necessitates a technique to help the consumer find the right game at the right time. This paper introduces HybridRank, a novel hybrid algorithm to deliver recommendations for mobile games. This technique is based on a personalized random walk approach, with the incorporation of...

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  • White Papers // Oct 2014

    A Hybrid Strategy for Privacy-Preserving Recommendations for Mobile Shopping

    To calculate recommendations, recommender systems collect and store huge amounts of users' personal data such as preferences, interaction behavior, or demographic information. If these data are used for other purposes or get into the wrong hands, the privacy of the users can be compromised. Thus, service providers are confronted with...

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  • White Papers // Oct 2014

    Towards Testing Model Transformation Chains Using Precondition Construction in Algebraic Graph Transformation

    Complex model-based tools such as code generators are typically designed as chains of model transformations taking as input a model of a software application and transforming it through several intermediate steps and representations. The complexity of intermediate models is such that testing is more conveniently done on the integrated chain,...

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  • White Papers // Sep 2014

    Analytical Modeling of the IEEE 802.11e EDCA Network with Contention Free Burst

    Contention Free Burst (CFB) is a promising burst transmission scheme defined in the IEEE 802.11e Medium Access Control (MAC) protocol to achieve differentiated Quality of Service (QoS) and improve the utilization of the wireless scarce bandwidth. Although modeling and performance analysis of the IEEE 802.11e network have attracted tremendous research...

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  • White Papers // Sep 2014

    Derivation of a Queuing Network Model for Structured P2P Architectures

    Peer-To-Peer (P2P) networks have using commonly used for tasks such as file sharing or file distribution, and for building distributed applications in large scale network. Their performance measures are generally based on simulation methods software such as NS-2, P2PSim, OpenNet, etc. Hence, the absence of a validation of the simulation...

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  • White Papers // Sep 2014

    Applying Data Fragmentation in IEEE 802.15.4: Modeling and Analysis Under Unsaturated Traffic

    The IEEE 802.15.4 standard, which is developed for low rate applications, offers low latency and energy consumption for wireless sensor networks. The use of the standardized slotted Carrier Sense Multiple Access (CSMA/CA), as a channel access mechanism, can, however, lead to wastage of the bandwidth utilization and an additional transmission...

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  • White Papers // Sep 2014

    Mapping OCL Constraints Into CTL-Like Logic and SML for UML Validation

    The UML (Unified Modeling Language) graphical models miss providing some pertinent elements of specification as constraints over objects and operations. To fill this lack, OCL (Object Constraint Language) has been developed by IBM and integrated to UML as a modern and formal modeling language, which is easy to learn and...

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  • White Papers // Sep 2014

    Cross-Layer Energy-Aware Protocol for Wireless Sensor Networks

    The resource limited nature of WSNs requires that protocols implemented on these networks be energy-efficient, scalable and distributed. In this paper, the authors present a novel combined routing and MAC protocol. The protocol achieves energy efficiency by minimizing signaling overhead through stateless routing decisions that are made at the receiver...

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  • White Papers // Sep 2014

    Comparison of Routing Protocols in Wireless Sensor Networks

    Several routing protocols have been proposed to maximize the sensor networks lifetime. However, most of these solutions try to find an energy efficient path and don't account for energy consumption balancing in sensor network. This usually leads to network partitioning. The aim of this paper is to evaluate, analyze and...

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  • White Papers // Sep 2014

    Fairness Improvement of MAC in Wireless Ad Hoc Networks

    There are many Medium Access Control (MAC) protocols proposed to achieve fairness in presence of hidden and/or exposed nodes. In a general approach to address the problem of fairness is proposed. This approach defines a fairness index and the goal is to minimize this fairness index to achieve fairness. In...

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  • White Papers // Sep 2014

    Model-Checking Cloud Systems Using BigMC

    Cloud computing is a promising concept in the IT evolution that has increasingly attracted attention from both industry and academic sectors. However, it has introduced new security problems and obstacles. Since formal methods provide a reliable mathematical basis giving rise to safely analyzable and easily verifiable models, this paper, the...

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  • White Papers // Sep 2014

    Coping with Spoofed PS-Poll Based DoS Attack in IEEE 802.11 Networks

    IEEE 802.11 networks are particularly vulnerable to DoS (Denial of Service) attacks targeting the network availability. In this paper, the authors focus on the PS-Poll based DoS attack, where the attacker spoofs the polling frame on behalf of the client in order to discard the client's buffered packets at the...

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  • White Papers // Sep 2014

    Graph Clustering Evaluation Metrics as Software Metrics

    Graph Clustering Evaluation (GCE) metrics quantify the quality of clusters obtained by graph clustering (community detection) algorithms. In this paper, the authors argue that GCE metrics can be applied on graph representations of software systems in order to evaluate the degree of cohesiveness of software entities. In contrast to widely...

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  • White Papers // Sep 2014

    Feature Models at Run Time: Feature Middleware for Multi-Tenant SaaS Applications

    Software Product Line Engineering (SPLE) techniques revolve around a central variability model which in many cases is a feature model that documents the logical capabilities of the system as features and the variability relationships between them. In more traditional SPLE, this feature model is a result of domain analysis and...

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  • White Papers // Sep 2014

    Approaches for Test Case Generation From UML Diagrams

    Model Based Testing (MBT) is an important approach with many advantages that can reduce the cost and increase the effectiveness and quality of a testing procedure. In MBT, test cases can be derived from different models, also from the popularly used UML diagrams. Different UML diagrams include various important pieces...

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  • White Papers // Aug 2011

    Joint BS Selection and Subcarrier Assignment for Multicell Heterogeneous OFDM Unicasting

    In this paper, the resource allocation is studied for Orthogonal Frequency Division Multiplexing (OFDM) unicasting by multiple Base Stations (BSs). In the considered scenario, each user is restricted to being covered by one BS, i.e., BS selection, while each subcarrier is assigned to at most one user, i.e., subcarrier assignment....

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  • White Papers // Oct 2010

    Low Complexity Joint Channel Estimation and Decoding for LDPC Coded MIMO-OFDM Systems

    In this paper, a joint iterative channel estimation and Low-Density Parity-Check (LDPC) decoding algorithm based on factor graphs and the sum-product algorithm is proposed for Orthogonal Frequency Division Multiplexing (OFDM) systems employing multiple transmit and receive antennas (MIMO). By modeling time-varying frequency-selective fading channels as Auto-Regressive (AR) processes and approximating...

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  • White Papers // May 2011

    Ontology-Based Corpus Generation for Web Comment Analysis

    In the study of technology acceptance the survey and analysis of user opinions is crucial to identify acceptance-relevant factors. In addition to topic-related surveys, which require high user willingness, the World Wide Web poses a huge collection of user discussions and comments to serve as a basis for further analysis....

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  • White Papers // Mar 2011

    Efficient Implementation and Evaluation of Parallel Radio Wave Propagation

    For planning, analysis, and optimization of modern, self organizing radio networks field strength prediction plays an essential role. A huge number of predictions is needed for planning purposes while high quality and level of detail are important as well. In this paper, the authors present a promising ray optical approach...

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  • White Papers // May 2012

    Distributed Compressed Sensing for the MIMO MAC With Correlated Sources

    In this paper, the authors consider the transmission of jointly sparse signals over a MIMO MAC composed of two transmitters and one receiver. Distributed compression is performed at the transmitters using a liner transformation and joint reconstruction at the receiver is enabled using the theory of distributed compressed sensing. The...

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  • White Papers // Jun 2012

    Detecting Irregularities in Blog Comment Language Affecting POS Tagging Accuracy

    Studying technology acceptance requires the survey and analysis of user opinions to identify acceptance-relevant factors. In addition to surveys, Web 2.0 poses a huge collection of user comments regarding different technologies. Extracting acceptance-relevant factors and user opinions from such comments requires the application of Natural Language Processing (NLP) methods, particularly...

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  • White Papers // May 2012

    Dynamic Cell Association for Downlink Sum Rate Maximization in Multi-Cell Heterogeneous Networks

    In this paper, the authors consider a heterogeneous network consisting in several macro nodes and pico nodes. The goal is to associate users, belonging to this network, to one of the nodes, while maximizing the sum rate of all users. They also want to analyze the load balancing achieved by...

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  • White Papers // Jan 2012

    Field Strength Prediction for Environment Aware MIMO Channel Models

    For planning, analysis, and optimization of modern, self organizing radio networks field strength prediction plays an essential role. A huge number of predictions is needed for planning purposes while high quality and level of detail are important as well. In this paper, the authors present a flexible ray optical approach...

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  • White Papers // Jan 2012

    Autoregressive Modeling of Frequency Selective Channels for Synchronized OFDM Systems

    In this paper, an Auto-Regressive (AR) channel model for simulating frequency selective channels in synchronized Orthogonal Frequency Division Multiplexing (OFDM) systems is proposed. By frequency domain AR filtering, the number of Rayleigh processes for generating the Channel Frequency Response (CFR) is reduced. Thus, this model is able to achieve a...

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  • White Papers // Feb 2012

    Extended Cyclostationary Signatures for OFDM-Based Cognitive Radio

    Cyclostationary signatures have been shown to be an effective method for OFDM network synchronization and Cognitive Radio coordination. In this paper, an extended method that utilizes cyclostationary signatures for signal parameter identification of OFDM-based Cognitive Radio nodes is presented. The scenario, implemented on a GNU Radio based evaluation platform, shows...

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  • White Papers // Mar 2012

    Upper-Bounding Rate Distortion Functions Based on the Minimum Mean-Square Error

    The authors derive a new upper bound on the rate distortion function for arbitrary memoryless sources, which is based on the relation between mutual information and minimum mean-square error discovered by Guo et al.. This upper bound is in general tighter than the well known upper bound given by the...

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  • White Papers // Nov 2011

    Robust Planning of Green Wireless Networks

    Current methods dealing with the energy efficient wireless network planning problem require a static model. However, bit rate requirements vary and rise over time, users move around and path gain fluctuates. In this paper, robust optimization is applied to deal with demand uncertainty. The authors present a robust optimization model...

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  • White Papers // Jul 2011

    Short Huffman Codes Producing 1s Half of the Time

    The design of the channel part of a digital communication system (e.g., error correction, modulation) is heavily based on the assumption that the data to be transmitted forms a fair bit stream. However, simple source encoders such as short Huffman codes generate bit streams that poorly match this assumption. As...

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  • White Papers // Sep 2011

    Operating LDPC Codes With Zero Shaping Gap

    Unequal transition probabilities between input and output symbols, input power constraints, or input symbols of unequal durations can lead to non-uniform capacity achieving input distributions for communication channels. Using uniform input distributions reduces the achievable rate, which is called the shaping gap. Gallager's idea for reliable communication with zero shaping...

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  • White Papers // Nov 2011

    Zero-Padded Symmetric Conjugate Technique for Intercarrier Interference Cancellation in MIMO-OFDM Systems

    This paper proposes a zero-padded symmetric conjugate self-cancellation technique in Orthogonal Frequency Division Multiplexing (OFDM) systems by padding zero in between two consecutive symbols for mitigating Inter-Carrier Interference (ICI) caused by a frequency offset in MIMO systems. The proposed system is not limited to the real-value channels as required in...

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  • White Papers // Nov 2011

    On the Performance of Cooperative Multihop Communications

    Cooperative communications is a promising technology to improve the performance of wireless networks. In this paper, the authors investigate the performance of a multihop communication system with regenerative relays in terms of Bit Error Rate (BER). They propose low complexity techniques, including a max-min cooperative approach I and II, for...

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  • White Papers // Feb 2011

    Matching Dyadic Distributions to Channels

    Many communication channels with discrete input have non-uniform capacity achieving Probability Mass Functions (PMF). By parsing a stream of independent and equiprobable bits according to a full prefix-free code, a modulator can generate dyadic PMFs at the channel input. In this paper, the authors show that for discrete memoryless channels...

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  • White Papers // Jan 2011

    Increasing Signaling Power Not Necessarily Improves Channel Capacity

    This paper is inspired by the general question of how to choose signaling points from a bounded set such that capacity of the corresponding channel is maximized. Since, subject to peak power constraints capacity achieving distributions become discrete, this question is most relevant for practical application. However, a solution seems...

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  • White Papers // Jan 2011

    Fast Radio Wave Propagation Prediction by Heterogeneous Parallel Architectures With Incoherent Memor

    The present correspondence deals with radio wave propagation for urban scenarios on the cell broadband engine. Binary space partitioning trees are used to split the building data into manageable size for the parallel units of the cell. By choosing the size of the tree leafs both data transfer between units...

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  • White Papers // Sep 2010

    Optimization of Cooperative Spectrum Sensing and Implementation on Software Defined Radios

    Reliable detection of primary user activity by spectrum sensing is a crucial issue of cognitive radio systems. The cooperative spectrum sensing is to combine the detection results of multiple cognitive radios in order to maximize the probability of detecting unused spectrum while meeting a required reliability of detecting primary user...

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  • White Papers // Oct 2010

    MIMO Broadcast Channel Rate Region With Linear Precoding at High SNR: No Full Multiplexing Case

    In this paper, the rate region of the two user MIMO Broadcast Channel (BC) with linear filtering at high Signal-to-Noise Ratio (SNR) is studied when time sharing is not available and the transmitter has fewer antennas than the sum of the receiving antennas. To reach the boundary of the rate...

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  • White Papers // Sep 2010

    Throughput, Bit-Cost, Network State Information: Tradeoffs in Cooperative CSMA Protocols

    In wireless local area networks, spatially varying channel conditions result in a severe performance discrepancy between different nodes in the uplink, depending on their position. Both throughput and energy expense are affected. Cooperative protocols were proposed to mitigate these discrepancies. However, additional Network State Information (NSI) from other nodes is...

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  • White Papers // Jun 2010

    Factor Graph Based Detection and Channel Estimation for MIMO-OFDM Systems in Doubly Selective Channel

    Based on the factor graph, a joint channel estimation and detection method is proposed for Orthogonal Frequency Division Multiplexing (OFDM) systems employing multiple transmit and receive antennas (MIMO). Using belief propagation, statistics of the fast varying MIMO multipath channel are utilized in estimating channel coefficients. By proper message scheduling and...

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  • White Papers // Sep 2010

    Generalised Link-Layer Adaptation With Higher-Layer Criteria for Energy-Constrained and Energy-Sufficient Data Terminals

    It has long been recognised that a wireless communication system can be more efficient if link-layer parameters such as modulation order are adapted to the channel conditions. The most common optimising criterion is spectral efficiency (bps/Hertz) subject to very low bit-error constraint. But this criterion is not appropriate for practical...

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  • White Papers // Feb 2010

    A Body-Coupled Communication and Radio Frequency Dual Technology Cooperation Protocol for Body-Area Networks

    Body-Area Networks (BANs) are Wireless Sensor Networks (WSNs) that operate in close proximity to the human body, being used for example for distributed wireless medical body sensors. Current implementations of BANs use standardized Radio Frequency (RF) technologies like IEEE 802.15.4, and do not account the characteristics of the body channel,...

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  • White Papers // Apr 2010

    Performance Evaluation of Sensor Fusion With Side Information

    The efficient evaluation of fusion algorithms becomes particularly important when different fusion schemes have to be compared with respect to an underlying performance metric. In this paper, the authors present explicit expressions for the global error probabilities of sensor fusion with side information for distributed detection applications. In the considered...

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  • White Papers // Mar 2010

    Generalised Water-Filling: Costly Power Optimally Allocated to Sub-Carriers Under a General Concave Performance Function

    A data terminal seeks the optimal power allocation for M sub-carriers under a general concave performance function ("Capacity"), and a per-Watt price. The value to the terminal of one transferred information bit, as well as the noise-normalised channel gains for each sub-carrier are the critical parameters. The authors provide the...

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  • White Papers // Mar 2010

    Simple Decentralised Market-Oriented Allocation of Sub-Channels and Power for Access-Point to Terminal Multi-Carrier Communication

    Common auction formats are well-understood, relatively simple mechanism which have long been used for allocating an indivisible good to the party that values it the most, for such reasons as speed of allocation, discovery of the true "Value" of the object, and fraud prevention. Various auction schemes have been proposed...

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  • White Papers // Jun 2010

    Capacity of General Discrete Noiseless Channels

    This paper concerns the capacity of the discrete noiseless channel introduced by Shannon. A sufficient condition is given for the capacity to be well-defined. For a general discrete noiseless channel allowing non-integer valued symbol weights, it is shown that the capacity - if well-defined - can be determined from the...

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  • White Papers // Jul 2012

    Reachability of the Capacity in Parallel Quantised Channels

    Based upon profound knowledge about wireless communication systems that was gathered during the past decades, modelling biological systems analogously has become more and more popular. Although the assumptions about the latter are sometimes less reliable than those about technical systems, some models have proven useful in explaining the behaviour of...

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  • White Papers // May 2012

    Mesh-DHT: A Locality-Based Distributed Look-Up Structure for Wireless Mesh Networks

    Distributed Hash Tables (DHTs) offer an elegant and fully distributed solution for reliably storing and retrieving data. Wireless Mesh Networks (WMNs) envision a fully decentralized fashion, and as such require efficient decentralized mechanisms for service discovery, mobility support and data storage and retrieval. Hence, DHTs and WMNs seem to complement...

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  • White Papers // May 2012

    On the Performance of Cellular Network Deployments in TV Whitespaces

    In this paper, the authors analyze the prospects of deploying a cellular network in the TV whitespaces. They study the challenges of planning for a large-scale transmitter network that is constrained by an interference-to-primary regulation. For this purpose they derive a novel methodology to maximize the downlink capacity at the...

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  • White Papers // Oct 2012

    Rate Selection Analysis Under Semi-Persistent Scheduling in LTE Networks

    Upcoming LTE networks have basically two different modes for scheduling data in the down-link by the base station. Dynamic scheduling brings the advantage of exploiting instantaneous channel state information while it puts on the other hand a significant burden on the system in terms of overhead and computation requirements. Especially...

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  • White Papers // Oct 2012

    The Outage Performance of Realtime Transmission in Multiple Asynchronous Relays Enhanced OFDM System

    This paper considers the outage performance of multiple relays transmission in Orthogonal Frequency Division Multiplexing (OFDM) systems. Relaying has been suggested in general to improve the reliability of wireless systems significantly and is therefore a candidate for wireless industrial communication systems that need to meet tough latency and outage requirements....

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  • White Papers // Jan 2013

    On the Outage Probability and Effective Capacity of Multiple Decode-and-Forward Relay System

    This paper investigates the quality-of-service performance of multiple decode-and-forward relay system. In particular, the authors study the outage probability and effective capacity performance of the system based on average channel gain. First, a closed-form expression of outage probability is derived which is more concise than the previous work. Second, they...

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  • White Papers // Aug 2012

    Distributed TV Spectrum Allocation for Cognitive Cellular Network Under Game Theoretical Framework

    This paper proposes efficient schemes for wireless cellular base stations to utilize TV white spectrum (such base stations referred to as white base stations - WBS), so that WBSes can provide good services to their end terminals without violating the incumbent TV services. In particular, the authors consider two complementary...

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  • White Papers // Apr 2012

    Multi-Level Parallelism for Time-And Cost-Efficient Parallel Discrete Event Simulation on GPUs

    Developing complex technical systems requires a systematic exploration of the given design space in order to identify optimal system configurations. However, studying the effects and interactions of even a small number of system parameters often requires an extensive number of simulation runs. This in turn results in excessive runtime demands...

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  • White Papers // Mar 2012

    Know Thy Simulation Model: Analyzing Event Interactions for Probabilistic Synchronization in Parallel Simulations

    Efficiently scheduling and synchronizing parallel event execution constitutes the fundamental challenge in parallel discrete event simulation. Existing synchronization algorithms typically do not analyze event interactions within the simulation model - mainly to minimize runtime overhead and complexity. However, the authors argue that disregarding event interactions results in a lack of...

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  • White Papers // May 2011

    Predicting Runtime Performance Bounds of Expanded Parallel Discrete Event Simulations

    Predicting and analyzing runtime performance characteristics is a vital step in the development process of parallel discrete event simulations. For instance, model developers need to identify and eliminate performance bottlenecks within a simulation model in order to derive a model structure that aids parallel execution. Similarly, developers of parallel simulation...

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  • White Papers // May 2010

    A Game-Theoretic Approach to Routing Under Adversarial Conditions

    The authors present a game-theoretic framework for modeling and solving routing problems in dynamically changing networks. The model covers the aspects of reactivity and non-termination, and it is motivated by quality-of-service provisioning in cognitive radio networks where data transmissions are interfered by primary systems. More precisely, they propose an infinite...

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