University of Mary Washington

Displaying 41-80 of 144 results

  • White Papers // Jul 2012

    A Policy-Based Approach to Smart Cloud Services

    Virtualized service models are now emerging and redefining the way information technology is delivered. Managing these services efficiently over the cloud is an open challenge. The authors are developing a policy-based integrated framework for automating acquisition and consumption of Cloud services. They have developed a tool, Smart Cloud Services tool,...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Signal Reflection-Enabled Geographical Routing for Underwater Sensor Networks

    The 3-D nature of the underwater environment has made geographical-routing a popular choice in UnderWater Acoustic Sensor Networks (UW-ASNs). A geographical (geo) routing protocol works by using the position information to find the best route from a source to a destination. These algorithms, often try to minimize the Line-Of-Sight (LOS)...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Providing Location Anonymity in a Multi-Base Station Wireless Sensor Network

    Wireless Sensor Networks (WSNs) often operate in inhospitable environments to serve mission-critical and security sensitive applications that involve hostile adversaries. These adversaries are eager to disrupt the WSN operation. Given the important role that the Base-Station (BS) plays in a WSN, the adversary opts to identify the BS and determine...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Optimized Interconnection of Disjoint Wireless Sensor Network Segments Using K Mobile Data Collectors

    Due to harsh environmental conditions a Wireless Sensor Network (WSN) may suffer from large scale damage where many nodes fail simultaneously and thus the network gets partitioned into several disjoint network segments. Restoring intersegment connectivity is essential to avoid negative effects on the application. Employing Mobile Data Collectors (MDCs), which...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Optimal Frequency Selection for Energy Efficient Underwater Acoustic Networks

    The underwater acoustic channel is characterized by a path loss that is dependent on both the distance and the frequency of communication. Given this dependence, it has been previously demonstrated that for a given communication distance, there is an optimal operating frequency, where conditions for signal propagation and noise are...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Energy-Efficient Cellular Network Operation Via Base Station Cooperation

    The rising cost of energy and increased environmental awareness has sparked a keen interest in the development and deployment of energy-efficient communication technologies. The energy efficiency of cellular networks can be increased significantly by selectively switching off some of the Base Stations (BSs) during periods of low traffic load. In...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Indirect Reciprocity Game Modelling for Secure Wireless Networks

    The authors formulate the wireless security problem as an indirect reciprocity game, and propose a security mechanism that applies the indirect reciprocity principle to suppress attacks in wireless networks. In this system, a large number of nodes cooperate to reject the network access requests from attackers during the punishment periods....

    Provided By University of Mary Washington

  • White Papers // May 2012

    Network Connectivity With Heterogeneous Mobility

    The authors study the issue of Mobile Wireless Network (MWN) connectivity. In particular, they investigate the smallest communication or transmission range of the nodes necessary for connectivity of MWNs, which they call the Critical Transmission Range (CTR). Unlike many of existing studies, however, the mobilities of the nodes are not...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Error Performances of Multiple Access System Using Analog Network Coding

    In this paper, the authors study the error performances of the multiple access system using Analog Network Coding (ANC), where all the users broadcast their data to the relays and destination simultaneously in the first phase, and the relays forward the source messages that have been mixed in the air...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Cooperation Stimulation in Cooperative Communications: An Indirect Reciprocity Game

    The viability of cooperative communications largely depends on the willingness of users to help. However, in future wireless networks where users are rational and pursue different objectives, they will not help relay information for others unless this can improve their own utilities. Therefore, it is very important to study the...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Vehicular Networking for Intelligent and Autonomous Traffic Management

    Traffic congestion has become a daily problem that most people suffer. This not only impacts the productivity of the population but also poses a safety risk. Most of the technologies for intelligent highways focus on safety measures and increased driver awareness, and expect a centralized management for the traffic flow....

    Provided By University of Mary Washington

  • White Papers // May 2012

    A Cheat-Proof Game Theoretic Demand Response Scheme for Smart Grids

    While demand response has achieved promising results on making the power grid more efficient and reliable, the additional dynamics and flexibility brought by demand response also increase the uncertainty and complexity of the centralized load forecast. In this paper, the authors propose a game theoretic demand response scheme that can...

    Provided By University of Mary Washington

  • White Papers // May 2012

    A Binary Classification Framework for Two-Stage Multiple Kernel Learning

    With the advent of kernel methods, automating the task of specifying a suitable kernel has become increasingly important. In this context, the Multiple Kernel Learning (MKL) problem of finding a combination of pre-specified base kernels that is suitable for the task at hand has received significant attention from researchers. In...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Heuristics for Speeding Up Betweenness Centrality Computation

    The authors propose and evaluate two complementary heuristics to speed up exact computation of the shortest-path betweenness centrality. Both heuristics are relatively simple adaptations of the standard algorithm for betweenness centrality. Consequently, they generalize the computation of edge betweenness and most other variants, and can be used to further speed...

    Provided By University of Mary Washington

  • White Papers // May 2012

    On the Sum Secure Degrees of Freedom of Two-Unicast Layered Wireless Networks

    The authors consider a two-unicast layered network where two transmitters wish to have reliable and secure communication with their respective receivers simultaneously, by utilizing a layered network between the transmitters and receivers. The single-layer version of this network is an interference channel, whose capacity is unknown in general; it is...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Throughput and Stability for Relay-Assisted Wireless Broadcast with Network Coding

    The throughput and stability properties of wireless network coding are evaluated for an arbitrary number of terminals exchanging broadcast traffic with the aid of a relay. First, coding and scheduling schemes are derived that minimize the number of transmissions needed for each node to broadcast one packet. For stochastically varying...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Energy Cooperation in Energy Harvesting Wireless Communications

    The authors consider a simple multi-hop communication scenario composed of a source node, a relay node and a destination node where the source and the relay can harvest energy from the nature. Energy required for communication arrives (is harvested) at the transmitter and an unlimited battery stores it before being...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Energy State Amplification in an Energy Harvesting Communication System

    In energy harvesting communication systems, the energy required for message transmission is maintained by an exogenous energy arrival process independent of the message. This links the problem of communication with an energy harvesting transmitter to the problem of communication over state-dependent channels. In particular, if the transmitter has no battery,...

    Provided By University of Mary Washington

  • White Papers // May 2012

    An Outer Bound for the Vector Gaussian CEO Problem

    The authors study the vector Gaussian CEO problem, and provide an outer bound for its rate-distortion region. They obtain their outer bound by evaluating an outer bound for the multi-terminal source coding problem by means of a technique relying on the de Bruijn identity and the properties of the Fisher...

    Provided By University of Mary Washington

  • White Papers // Apr 2012

    DEMB: Cache-Aware Scheduling for Distributed Query Processing

    Leveraging data in distributed caches for large scale query processing applications is becoming more important, given current trends toward building large scalable distributed systems by connecting multiple heterogeneous less powerful machines rather than purchasing expensive homogeneous and very powerful machines. As more servers are added to such clusters, more memory...

    Provided By University of Mary Washington

  • White Papers // Apr 2012

    Privacy Control in Smart Phones Using Semantically Rich Reasoning and Context Modeling

    The authors present their ongoing work on user data and contextual privacy preservation in mobile devices through semantic reasoning. Recent advances in context modeling, tracking and collaborative localization have led to the emergence of a new class of Smartphone applications that can access and share embedded sensor data. Unfortunately, this...

    Provided By University of Mary Washington

  • White Papers // Apr 2012

    A Knowledge-Based Approach to Intrusion Detection Modeling

    Current state of the art Intrusion Detection and Prevention Systems (IDPS) are signature-based systems that detect threats and vulnerabilities by cross-referencing the threat or vulnerability signatures in their databases. These systems are incapable of taking advantage of heterogeneous data sources for analysis of system activities for threat detection. This paper...

    Provided By University of Mary Washington

  • White Papers // Apr 2012

    Buffer-On-Board Memory System

    The design and implementation of the commodity memory architecture has resulted in significant performance and capacity limitations. To circumvent these limitations, designers and vendors have begun to place intermediate logic between the CPU and DRAM. This additional logic has two functions: to control the DRAM and to communicate with the...

    Provided By University of Mary Washington

  • White Papers // Feb 2012

    A Policy Driven Semantic Approach to Data Usage Management

    As the amount of information available on the web has increased, several privacy and security issues around the use of such information have arisen. Government (and private) entities are able to gather and analyze data from several disparate sources with ease. This ability to do large scale analytics of publicly...

    Provided By University of Mary Washington

  • White Papers // Feb 2012

    Understanding Issues in Cloud Forensics: Two Hypothetical Case Studies

    The inevitable vulnerabilities and criminal targeting of cloud environments demand an understanding of how digital forensic investigations of the cloud can be accomplished. The authors present two hypothetical case studies of cloud crimes; child pornography being hosted in the cloud, and a compromised cloud-based website. Their cases highlight shortcomings of...

    Provided By University of Mary Washington

  • White Papers // Feb 2012

    Deaf Cooperation for Secrecy with a Multi-Antenna Helper

    In this paper, the authors investigate the roles of Cooperative Jamming (CJ) and Noise Forwarding (NF) in improving the achievable secrecy rates of a Gaussian WireTap channel (GWT) when the helper node is equipped with multiple antennas. They decompose the channel from the helper to the eavesdropper into two orthogonal...

    Provided By University of Mary Washington

  • White Papers // Feb 2012

    Mapping Parameterized Cyclo-Static Dataflow Graphs Onto Configurable Hardware

    In recent years, parameterized dataflow has evolved as a useful framework for modeling synchronous and cyclo-static graphs in which arbitrary parameters can be changed dynamically. Parameterized dataflow has proven to have significant expressive power for managing dynamics of DSP applications in important ways. However, efficient hardware synthesis techniques for parameterized...

    Provided By University of Mary Washington

  • White Papers // Jan 2012

    AWGN Channel Under Time-Varying Amplitude Constraints With Causal Information at the Transmitter

    The authors consider the classical AWGN channel where the channel input is constrained to an amplitude constraint that stochastically varies at each channel use, independent of the message. This is an abstraction of an energy harvesting transmitter where the code symbol energy at each channel use is determined by an...

    Provided By University of Mary Washington

  • White Papers // Oct 2011

    Optimal Scheduling Over Fading Broadcast Channels With an Energy Harvesting Transmitter

    The authors consider an energy harvesting transmitter sending messages to two users over a fading AWGN broadcast channel. Energy required for communication arrives (is harvested) at the transmitter and a finite capacity battery stores it before being consumed for transmission. Based on a deterministic energy arrival and fading model, they...

    Provided By University of Mary Washington

  • White Papers // Oct 2011

    Optimal Transmission Policies Over Vector Gaussian Broadcast Channels With Energy Harvesting Transmitters

    The authors consider an energy harvesting transmitter sending messages to two users over a vector broadcast channel. Energy required for communication arrives (is harvested) at the transmitter and a finite-capacity battery stores it before being consumed for transmission. Under off-line knowledge of energy arrivals, they obtain the trade-off between the...

    Provided By University of Mary Washington

  • White Papers // Oct 2011

    Teaching Cross-Platform Design and Testing Methods for Embedded Systems Using DICE

    In this paper, the authors present a motivation for deep integration into embedded systems education of testing-driven design and methods for cross-platform and language-independent test suite development. To support these objectives, they introduce instructional applications of DICE (the DSPCAD Integrative Command line Environment), which is a package of utilities that...

    Provided By University of Mary Washington

  • White Papers // Oct 2011

    Vectorization and Mapping of Software Defined Radio Applications on Heterogeneous Multi-Processor Platforms

    A variety of multiprocessor architectures have proliferated even for off-the-shelf computing platforms. To improve performance and productivity for common heterogeneous systems, the authors have developed a workflow to generate efficient solutions. By starting with a formal description of an application and the mapping problem they are able to generate a...

    Provided By University of Mary Washington

  • White Papers // Sep 2011

    Rate-Equivocation Region of Cyclic Shift Symmetric Wiretap Channels

    In this paper, the authors study cyclic shift symmetric wiretap channels in which the channels between Alice and Bob and Alice and Eve are both cyclic shift symmetric. They characterize the rate-equivocation region by determining the optimal selection of rate splitting U and channel prefixing V for these channels. They...

    Provided By University of Mary Washington

  • White Papers // Sep 2011

    Secure Lossy Source Coding With Side Information

    The authors study the problem of secure lossy source coding with side information. In all works on this problem, either the equivocation of the source at the eavesdropper or the equivocation of the legitimate user's reconstruction of the source at the eavesdropper is used as the measure of secrecy. In...

    Provided By University of Mary Washington

  • White Papers // Sep 2011

    Data Structure Choices for On-the-Fly Model Checking of Real-Time Systems

    In this paper, the authors study the performance of sparse-matrix-based data structures to represent clock zones (convex sets of clock values) in an on-the-fly predicate equation system model checker for timed automata. They analyze the impact of replacing the dense Difference Bound Matrix (DBM) with both the linked-list CRDZone and...

    Provided By University of Mary Washington

  • White Papers // Sep 2011

    Deaf Cooperation for Secrecy in Multiple-Relay Networks

    In this paper, the authors investigate the roles of Cooperative Jamming (CJ) and Noise Forwarding (NF) in improving the achievable secrecy rates of a Gaussian WireTap channel (GWT). In particular, they study the role of a deaf helper in confusing the eavesdropper in a GWT channel by either transmitting white...

    Provided By University of Mary Washington

  • White Papers // Aug 2011

    Cellular Traffic Offloading Through WiFi Networks

    Cellular networks are currently facing the challenges of mobile data explosion. High-end mobile phones and laptops double their mobile data traffic every year and this trend is expected to continue given the rapid development of mobile social applications. It is imperative that novel architectures be developed to handle such voluminous...

    Provided By University of Mary Washington

  • White Papers // Aug 2011

    Secure Lossy Transmission of Vector Gaussian Sources

    The authors explain the secure lossy transmission of a vector Gaussian source to a legitimate user in the presence of an eavesdropper, where both the legitimate user and the eavesdropper have vector Gaussian side information. The aim of the transmitter is to describe the source to the legitimate user in...

    Provided By University of Mary Washington

  • White Papers // Aug 2011

    Model-Based Precision Analysis and Optimization for Digital Signal Processors

    Embedded signal processing has witnessed explosive growth in recent years in both scientific and consumer applications, driving the need for complex, high-performance signal processing systems that are largely application driven. In order to efficiently implement these systems on programmable platforms such as Digital Signal Processors (DSPs), it is important to...

    Provided By University of Mary Washington

  • White Papers // Jul 2011

    Generating Linked Data by Inferring the Semantics of Tables

    Vast amounts of information are encoded in structured tables found in documents, on the web, and in spreadsheets or databases. Integrating or searching over this information benefits from understanding its intended meaning. Evidence for a table's meaning can be found in its column headers, cell values, implicit relations between columns,...

    Provided By University of Mary Washington

  • White Papers // Feb 2012

    Understanding Issues in Cloud Forensics: Two Hypothetical Case Studies

    The inevitable vulnerabilities and criminal targeting of cloud environments demand an understanding of how digital forensic investigations of the cloud can be accomplished. The authors present two hypothetical case studies of cloud crimes; child pornography being hosted in the cloud, and a compromised cloud-based website. Their cases highlight shortcomings of...

    Provided By University of Mary Washington

  • White Papers // Jan 2010

    Perfect Omniscience, Perfect Secrecy and Steiner Tree Packing

    The authors consider perfect secret key generation for a "Pair-wise independent network" model in which every pair of terminals share a random binary string, with the strings shared by distinct terminal pairs being mutually independent. The terminals are then allowed to communicate interactively over a public noiseless channel of unlimited...

    Provided By University of Mary Washington

  • White Papers // May 2013

    Non-Asymptotic and Second-Order Achievability Bounds for Source Coding with Side-Information

    In this paper, the authors proved a new non-asymptotic bound on the error probability for the WAK problem. They present a novel achievability bound for the Wyner-Ahlswede-Korner (WAK) problem of lossless source coding with rate-limited side-information. This bound is proved using ideas from channel simulation and channel resolvability. The bound...

    Provided By University of Mary Washington

  • White Papers // Jul 2012

    Gaussian Wiretap Channel With an Amplitude Constraint

    The authors consider the Gaussian wiretap channel with an amplitude constraint, i.e., a peak power constraint, on the channel input. They show that the entire rate-equivocation region of the Gaussian wiretap channel with an amplitude constraint is obtained by discrete input distributions with finite support. They prove this result by...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Energy Cooperation in Energy Harvesting Wireless Communications

    The authors consider a simple multi-hop communication scenario composed of a source node, a relay node and a destination node where the source and the relay can harvest energy from the nature. Energy required for communication arrives (is harvested) at the transmitter and an unlimited battery stores it before being...

    Provided By University of Mary Washington

  • White Papers // Oct 2011

    Optimal Scheduling Over Fading Broadcast Channels With an Energy Harvesting Transmitter

    The authors consider an energy harvesting transmitter sending messages to two users over a fading AWGN broadcast channel. Energy required for communication arrives (is harvested) at the transmitter and a finite capacity battery stores it before being consumed for transmission. Based on a deterministic energy arrival and fading model, they...

    Provided By University of Mary Washington

  • White Papers // Sep 2011

    Rate-Equivocation Region of Cyclic Shift Symmetric Wiretap Channels

    In this paper, the authors study cyclic shift symmetric wiretap channels in which the channels between Alice and Bob and Alice and Eve are both cyclic shift symmetric. They characterize the rate-equivocation region by determining the optimal selection of rate splitting U and channel prefixing V for these channels. They...

    Provided By University of Mary Washington

  • White Papers // Oct 2011

    Optimal Transmission Policies Over Vector Gaussian Broadcast Channels With Energy Harvesting Transmitters

    The authors consider an energy harvesting transmitter sending messages to two users over a vector broadcast channel. Energy required for communication arrives (is harvested) at the transmitter and a finite-capacity battery stores it before being consumed for transmission. Under off-line knowledge of energy arrivals, they obtain the trade-off between the...

    Provided By University of Mary Washington

  • White Papers // Jan 2012

    AWGN Channel Under Time-Varying Amplitude Constraints With Causal Information at the Transmitter

    The authors consider the classical AWGN channel where the channel input is constrained to an amplitude constraint that stochastically varies at each channel use, independent of the message. This is an abstraction of an energy harvesting transmitter where the code symbol energy at each channel use is determined by an...

    Provided By University of Mary Washington

  • White Papers // May 2011

    Wiretap Channels: Roles of Rate Splitting and Channel Prefixing

    Csiszar and Korner's characterization of the rate-equivocation region of a general wiretap channel involves two auxiliary random variables: U, which represents rate splitting and V, which represents channel prefixing. For some channels, one or both of these auxiliary random variables are unnecessary, simplifying the expression and evaluation of the rate-equivocation...

    Provided By University of Mary Washington

  • White Papers // Mar 2011

    Broadcasting With a Battery Limited Energy Harvesting Rechargeable Transmitter

    The authors consider the minimization of the transmission completion time with a battery limited energy harvesting transmitter in a two-user AWGN broadcast channel. The transmitter has fixed number of packets for each receiver and energy is modeled to arrive (be harvested) at the transmitter at random instants. The battery at...

    Provided By University of Mary Washington

  • White Papers // Jun 2010

    Information-Theoretic Analysis of an Energy Harvesting Communication System

    In energy harvesting communication systems, exogenous recharge process supplies energy for the data transmission and arriving energy can be buffered in a battery before consumption. Transmission is interrupted if there is not sufficient energy. The authors address communication with such random energy arrivals in an information-theoretic setting. Based on the...

    Provided By University of Mary Washington

  • White Papers // May 2013

    Binary Energy Harvesting Channel With Finite Energy Storage

    The authors consider the capacity of an energy harvesting communication channel with a finite-sized battery. As an abstraction of this problem, they consider a system where energy arrives at the encoder in multiples of a fixed quantity, and the physical layer is modeled accordingly as a finite discrete alphabet channel...

    Provided By University of Mary Washington

  • White Papers // Sep 2012

    Secure Degrees of Freedom of the Gaussian Wiretap Channel With Helpers

    The secrecy capacity of the canonical Gaussian wiretap channel does not scale with the transmit power, and hence, the secure d.o.f. of the Gaussian wiretap channel with no helpers is zero. It has been known that a strictly positive secure d.o.f. can be obtained in the Gaussian wiretap channel by...

    Provided By University of Mary Washington

  • White Papers // Sep 2011

    Secure Lossy Source Coding With Side Information

    The authors study the problem of secure lossy source coding with side information. In all works on this problem, either the equivocation of the source at the eavesdropper or the equivocation of the legitimate user's reconstruction of the source at the eavesdropper is used as the measure of secrecy. In...

    Provided By University of Mary Washington

  • White Papers // Oct 2009

    A New Achievable Ergodic Secrecy Rate Region for the Fading Multiple Access Wiretap Channel

    The authors give a new achievable ergodic secrecy rate region for the two-user fading multiple access wiretap channel. Their scheme creates a vector channel between the two transmitters and the intended receiver that has full-rank and creates another vector channel between the two transmitters and the eavesdropper whose rank is...

    Provided By University of Mary Washington

  • White Papers // Nov 2009

    Secrecy Capacity Region of the Degraded Compound Multi-Receiver Wiretap Channel

    The authors study the degraded compound multi-receiver wiretap channel, which consists of two groups of users and a group of eavesdroppers. They consider two different communication scenarios. In both scenarios, the transmitter sends two confidential messages, one for each group of users. In the first scenario, both messages need to...

    Provided By University of Mary Washington

  • White Papers // Jan 2013

    The Capacity Region of a Class of Discrete Degraded Interference Channels

    The authors provide a single-letter characterization for the capacity region of a class of Discrete Degraded Interference Channels (DDICs). The class of DDICs considered includes the Discrete Additive Degraded Interference Channel (DADIC) studied by Benzel. They show that for the class of DDICs studied, encoder cooperation does not increase the...

    Provided By University of Mary Washington

  • White Papers // Oct 2010

    Degraded Gaussian MIMO Multi-Receiver Wiretap Channel With Public and Confidential Messages

    The authors study the degraded multi-receiver wiretap channel with public and confidential messages. In this channel, there is a transmitter that wishes to communicate with two legitimate users in the presence of an external eavesdropper. The legitimate users and the eavesdropper satisfy a certain degradation order. In this paper, they...

    Provided By University of Mary Washington

  • White Papers // Sep 2010

    Capacity of a Class of Semi-Deterministic Primitive Relay Channels

    The authors characterize the capacity of a class of primitive relay channels. The primitive relay channel considered in this paper consists of a semi-deterministic broadcast channel to the relay and the decoder. The relay can help the message transmission through an orthogonal finite capacity link to the decoder. They show...

    Provided By University of Mary Washington

  • White Papers // Sep 2010

    Real Interference Alignment for the K-User Gaussian Interference Compound Wiretap Channel

    The authors study the K-user Gaussian interference wiretap channel with N external eavesdroppers. All the transmitters, receivers and eavesdroppers have a single antenna each. They propose an achievable scheme to lower bound the secure degrees of freedom (d.o.f.) for each transmitter-receiver pair. Their approach is based on the (real) interference...

    Provided By University of Mary Washington

  • White Papers // Mar 2009

    Peer-to-Peer File Sharing Game Using Correlated Equilibrium

    Peer-To-Peer (P2P) systems have become more and more popular in nowadays by providing decentralized, self-organizing and fault tolerant file sharing services. As the selfish users do not benefit from providing free service, they tend to download files from other users and yet not to upload for the others, resulting in...

    Provided By University of Mary Washington

  • White Papers // Nov 2012

    Anti Error Propagation Methods for Wireless Uplink Using Network Coding

    Wireless network coding suffers the error propagation issues that may severely degrade the diversity performance. In this paper, the authors develop two power scaling schemes at the relay side and two detection schemes at the receiver side, respectively, to mitigate error propagation in network-coded uplink channel and thus achieve full...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Heuristics for Speeding Up Betweenness Centrality Computation

    The authors propose and evaluate two complementary heuristics to speed up exact computation of the shortest-path betweenness centrality. Both heuristics are relatively simple adaptations of the standard algorithm for betweenness centrality. Consequently, they generalize the computation of edge betweenness and most other variants, and can be used to further speed...

    Provided By University of Mary Washington

  • White Papers // Jan 2013

    Optimization Based Rate Control for Multirate Multicast Sessions

    Multi-rate multicasting, where the receivers of a multicast group can receive service at different rates, is an efficient mode of data delivery for many real-time applications. In this paper, the authors address the problem of achieving rates that maximize the total receiver utility for multi-rate multicast sessions. This problem not...

    Provided By University of Mary Washington

  • White Papers // Jan 2013

    A Simple Rate Control Algorithm for Maximizing Total User Utility

    In this paper, the authors consider the rate control problem with the objective of maximizing the total user utility. It takes into account the possible differences in user requirements, and also provides a framework for achieving a wide range of fairness objectives. They propose a simple algorithm for achieving the...

    Provided By University of Mary Washington

  • White Papers // Oct 2009

    Implementing Information Paths in a Dense Wireless Sensor Network

    In a sensor network with information sources and a sink, the authors assume a single path between every location in the network and the destination. These abstract information paths represent the desired paths for transmission of information. If the number of sensor nodes is large enough to approximate information paths...

    Provided By University of Mary Washington

  • White Papers // Oct 2009

    Tiered Authentication of Multicast Traffic in Wireless Ad-Hoc Networks

    Multicast streams are the dominant application traffic pattern in many mission critical ad-hoc networks. The limited computation and communication resources, the large scale deployment and the unguaranteed connectivity to trusted authorities make known security solutions for wired and single-hop wireless networks inappropriate for such application environment. This paper promotes a...

    Provided By University of Mary Washington

  • White Papers // Dec 2012

    Two-Way and Multiple-Access Energy Harvesting Systems With Energy Cooperation

    The authors study the capacity regions of the Gaussian Two-Way Channel (TWC) and the Gaussian two-user Multiple Access Channel (MAC) with one-way energy transfer. In both scenarios, there are two users powered by energy harvesting devices communicating messages to each other or to an access point. They model these scenarios...

    Provided By University of Mary Washington

  • White Papers // Feb 2013

    Energy Cooperation in Energy Harvesting Two-Way Communications

    In this paper, the authors investigate a two-way communication channel where users can harvest energy from nature and energy can be transferred in one-way from one of the users to the other. Energy required for data transmission is randomly harvested by the users throughout the communication duration and users have...

    Provided By University of Mary Washington

  • White Papers // May 2012

    Energy State Amplification in an Energy Harvesting Communication System

    In energy harvesting communication systems, the energy required for message transmission is maintained by an exogenous energy arrival process independent of the message. This links the problem of communication with an energy harvesting transmitter to the problem of communication over state-dependent channels. In particular, if the transmitter has no battery,...

    Provided By University of Mary Washington

  • White Papers // Jul 2012

    Gaussian Wiretap Channel With a Batteryless Energy Harvesting Transmitter

    The authors study the Gaussian wiretap channel with an energy harvesting transmitter which does not have a battery to save energy. In the absence of a battery, the necessary transmission energy is maintained by an i.i.d. energy arrival process. They observe that this channel is an instance of the state-dependent...

    Provided By University of Mary Washington

  • White Papers // Feb 2010

    Ergodic Secret Alignment for the Fading Multiple Access Wiretap Channel

    In this paper, the authors provide a new achievable ergodic secrecy rate region for the multiple access wiretap channel in fading. Their achievable scheme is based on repeating each symbol at two fading instances, as in the original ergodic interference alignment technique of Nazer et. al. They choose the channel...

    Provided By University of Mary Washington

  • White Papers // Feb 2011

    Optimal Packet Scheduling in a Multiple Access Channel With Rechargeable Nodes

    In this paper, the authors investigate the optimal packet scheduling problem in a two-user multiple access communication system, where the transmitters are able to harvest energy from the nature. Under a deterministic system setting, they assume that the energy harvesting times and harvested energy amounts are known before the transmission...

    Provided By University of Mary Washington

  • White Papers // Apr 2009

    Outer Bounds for User Cooperation

    The authors obtain a dependence balance based outer bound on the capacity region of the two-user Multiple Access Channel with Generalized Feedback (MAC-GF). They investigate a Gaussian MAC with User-Cooperation (MAC-UC), where each transmitter receives an additive white Gaussian noise corrupted version of the channel input of the other transmitter....

    Provided By University of Mary Washington

  • White Papers // May 2009

    Delay Minimization in Multiple Access Channels

    The authors investigate a delay minimization problem in a multiple access wireless communication system. They consider a discrete-time non-fading Additive White Gaussian Noise (AWGN) multiple access channel. In each slot, bits arrive at the transmitters randomly according to some distribution, which is i.i.d. from user to user and from slot...

    Provided By University of Mary Washington

  • White Papers // Apr 2009

    Secrecy Capacity Region of the Gaussian Multi-Receiver Wiretap Channel

    The authors consider the Gaussian multi-receiver wiretap channel and evaluate its secrecy capacity region. This evaluation requires the identification of underlying auxiliary random variables. For this purpose, they first visit the converse proof of the scalar Gaussian broadcast channel, and show that this proof cannot be extended to this secrecy...

    Provided By University of Mary Washington

  • White Papers // Apr 2009

    On the Rate-Limited Gelfand-Pinsker Problem

    The authors study a rate-limited version of the well known problem of coding for channels with random parameters which was studied by Gelfand and Pinsker. In particular, they consider a state-dependent channel when the transmitter is supplied with the state information at a rate Re. They obtain a new upper...

    Provided By University of Mary Washington

  • White Papers // Apr 2010

    Gaussian MIMO Broadcast Channels with Common and Confidential Messages

    The authors study the two-user Gaussian Multiple-Input Multiple-Output (MIMO) broadcast channel with common and confidential messages. In this channel, the transmitter sends a common message to both users, and a confidential message to each user which is kept perfectly secret from the other user. They obtain the entire capacity region...

    Provided By University of Mary Washington

  • White Papers // Apr 2010

    On Gaussian MIMO Broadcast Channels with Common and Private Messages

    The authors study the Gaussian Multiple-Input Multiple-Output (MIMO) broadcast channel with common and private messages. They first obtain an outer bound for the capacity region of the two-user discrete memoryless broadcast channel with common and private messages. They next show that if jointly Gaussian random variables are sufficient to evaluate...

    Provided By University of Mary Washington