University of Maryland

Displaying 1-40 of 227 results

  • White Papers // Feb 2012

    Deaf Cooperation for Secrecy With Multiple Antennas at the 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 Maryland

  • White Papers // Feb 2012

    Deaf Cooperation and Relay Selection Strategies for Secure Communication 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 Maryland

  • White Papers // Jan 2012

    Secure Communication in Multiple Relay Networks Through Decode-and-Forward Strategies

    In this paper, the authors first study the Decode-and-Forward strategy for secrecy in a single-relay network. They propose a suboptimal Decode-and-Forward with Zero Forcing (DF/ZF) strategy for which they obtain the optimal power control policy. Next, they consider the multiple relay problem. They propose three different strategies based on DF/ZF....

    Provided By University of Maryland

  • White Papers // Jan 2012

    Formal Specification and Analysis of PCF Protocol in the 802.11 Standard Using Systems of Communicating Machines

    With the widespread usage of the 802.11 protocol, it becomes important to study the protocol operation. In this paper, the authors propose a formal model for the point coordination function of the 802.11 MAC layer using systems of communicating machines. Their goal is to analyze the protocol for safety and...

    Provided By University of Maryland

  • White Papers // Jan 2012

    Towards an Optimal Strategy for WLAN Location Determination Systems

    This paper presents a general analysis for the performance of WLAN location determination systems. In particular, the authors present an analytical method for calculating the average distance error and probability of error of WLAN location determination systems. These expressions are obtained with no assumptions regarding the distribution of signal strength...

    Provided By University of Maryland

  • White Papers // Jan 2012

    Kitsune: Efficient, General-Purpose Dynamic Software Updating for C

    Dynamic Software Updating (DSU) systems allow programs to be updated while running, thereby allowing developers to add features and fix bugs without downtime. This paper introduces Kitsune, a new DSU system for C whose design has three notable features. First, Kitsune's updating mechanism updates the whole program, not individual functions....

    Provided By University of Maryland

  • White Papers // Jan 2012

    Jamming Games for Power Controlled Medium Access With Dynamic Traffic

    Due to the broadcast nature of the wireless medium, wireless networks are highly susceptible to jamming attacks. Such attacks are often studied in a game theoretic framework under the assumption of uninterrupted traffic subject to continuous jamming opportunities. The authors analyze the effect of dynamically changing traffic on jamming games...

    Provided By University of Maryland

  • White Papers // Jan 2012

    Universally-Composable Two-Party Computation in Two Rounds

    Round complexity is a central measure of efficiency, and characterizing the round complexity of various cryptographic tasks is of both theoretical and practical importance. The authors show here a Universally Composable (UC) protocol (in the common reference string model) for two-party computation of any functionality, where both parties receive output,...

    Provided By University of Maryland

  • White Papers // Dec 2011

    Neighbor Discovery in a Wireless Sensor Network: Multipacket Reception Capability and Physical-Layer Signal Processing

    In randomly deployed networks, such as sensor networks, an important problem for each node is to discover its neighbor nodes so that the connectivity amongst nodes can be established. In this paper, the authors consider this problem by incorporating the physical layer parameters in contrast to the most of the...

    Provided By University of Maryland

  • White Papers // Dec 2011

    Chinese Restaurant Game - Part II: Applications to Wireless Networking, Cloud Computing, and Online Social Networking

    In this paper, the authors proposed a new game, called Chinese restaurant game, to analyze the social learning problem with negative network externality. The best responses of agents in the Chinese restaurant game with imperfect signals are constructed through a recursive method, and the influence of both learning and network...

    Provided By University of Maryland

  • White Papers // Oct 2011

    Wiretap Channels: Implications of the More Capable Condition and Cyclic Shift Symmetry

    Characterization of the rate-equivocation region of a general wiretap channel involves two auxiliary random variables: U, for rate splitting and V, for channel prefixing. Evaluation of regions involving auxiliary random variables is generally difficult. In this paper, the authors explore specific classes of wiretap channels for which the expression and...

    Provided By University of Maryland

  • White Papers // Oct 2011

    The Network Stack Trace: Performance Diagnosis for Networked Systems

    Transient network stalls that degrade application performance are frustrating to users and developers alike. Software bugs, network congestion, and intermittent connectivity all have the same symptoms - low throughput, high latency, and user-level timeouts. In this paper, the authors show how an end host can identify the sources of network...

    Provided By University of Maryland

  • White Papers // Sep 2011

    ITree: Efficiently Discovering High-Coverage Configurations Using Interaction Trees

    Software configurability has many benefits, but it also makes programs much harder to test, as in the worst case the program must be tested under every possible configuration. One potential remedy to this problem is Combinatorial Interaction Testing (CIT), in which typically the developer selects a strength t and then...

    Provided By University of Maryland

  • White Papers // Sep 2011

    Evaluating Dynamic Software Update Safety Using Systematic Testing

    Dynamic Software Updating (DSU) systems patch programs on the fly without incurring downtime. To avoid failures due to the updating process itself, many DSU systems employ timing restrictions. However, timing restrictions are theoretically imperfect, and their practical effectiveness is an open question. This paper presents the first significant empirical evaluation...

    Provided By University of Maryland

  • White Papers // Sep 2011

    Bandwidth Management for Mobile Media Delivery

    Mobile broadband networks such as 3G and WiMAX present unique challenges to media delivery. Rich media applications require high throughput and low end-to-end delay in order to maintain good quality. Due to the inherent noise in congestion signals (delay / loss) on mobile networks, existing bandwidth management approaches are unable...

    Provided By University of Maryland

  • White Papers // Aug 2011

    A Demo of Coco: A Compiler for Monadic Coercions in ML

    Combining monadic computations may induce a significant syntactic overhead. To allow monadic programming in direct style, the authors have developed Coco, a type-based tool that automatically rewrites ML code inserting necessary binds, unit, and morphisms between monads. This tool demonstration will show how to take advantage of Coco to facilitate...

    Provided By University of Maryland

  • White Papers // Aug 2011

    MultiOtter: Multiprocess Symbolic Execution

    Symbolic execution can be an effective technique for exploring large numbers of program paths, but it has generally been applied to programs running in isolation, whose inputs are files or command-line arguments. Programs that take inputs from other programs-servers, for example-have been beyond the reach of symbolic execution. To address...

    Provided By University of Maryland

  • White Papers // Jul 2011

    Motif-Based Topology Design for Efficient Performance by Networks of Mobile Autonomous Vehicles

    Networked systems of autonomous agents have emerged in a variety of applications such as collaborative robotics, mobile sensor networks and disaster relief operations. Complex phenomena are often observed in these systems due to the large number of agents, nonlinear interactions, locality of information transmission, and changes in the connectivity of...

    Provided By University of Maryland

  • White Papers // Jun 2011

    History-Free Sequential Aggregate Signatures

    Aggregation schemes allows to combine several cryptographic values like message authentication codes or signatures into a shorter value such that, despite compression, some notion of unforgeability is preserved. Recently, Eikemeier et al. (SCN 2010) considered the notion of history-free sequential aggregation for message authentication codes, where the sequentially-executed aggregation algorithm...

    Provided By University of Maryland

  • White Papers // Jun 2011

    Towards Shrink-Wrapped Security: Practically Incorporating Context Into Security Services

    The mobile workforce is rapidly increasing, and technological advances make it feasible for these workers to have ubiquitous access to a variety of resources with various protection requirements. The dynamic computing environment of these workers mandates a security paradigm in which security is tightly coupled with a user's current situation....

    Provided By University of Maryland

  • White Papers // Jun 2011

    Universally Composable Synchronous Computation

    In synchronous networks, protocols can achieve security guarantees that are not possible in an asynchronous world: i.e., they can simultaneously achieve input completeness (all honest parties' inputs are included in the computation) and guaranteed termination (honest parties do not "Hang" indefinitely). In practice, truly synchronous networks rarely exist, but synchrony...

    Provided By University of Maryland

  • White Papers // Jun 2011

    Directed Symbolic Execution

    In this paper, the authors study the problem of automatically finding program executions that reach a particular target line. This problem arises in many debugging scenarios; for example, a developer may want to confirm that a bug reported by a static analysis tool on a particular line is a true...

    Provided By University of Maryland

  • White Papers // Jun 2011

    Optimal Packet Scheduling in a Multiple Access Channel With Energy Harvesting Transmitters

    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 Maryland

  • White Papers // Jun 2011

    Multi-Receiver Wiretap Channel With Public and Confidential Messages

    The authors study the 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 transmitter sends a pair of public and confidential messages to each legitimate user. While there...

    Provided By University of Maryland

  • White Papers // May 2011

    Round Optimal Blind Signatures

    All known round optimal (i.e., two-move) blind signature schemes either need a common reference string, rely on random oracles, or assume the hardness of some interactive assumption. At Eurocrypt 2010, Fischlin and Schr?der showed that a broad class of three-move blind signature scheme cannot be instantiated in the standard model...

    Provided By University of Maryland

  • White Papers // May 2011

    Secure Multi-Party Computation of Boolean Circuits With Applications to Privacy in On-Line Marketplaces

    Protocols for generic secure Multi-Party Computation (MPC) come in two forms: they either represent the function being computed as a Boolean circuit or as an arithmetic circuit over a large field. Either type of protocol can be used for any function, but the choice of which type of protocol to...

    Provided By University of Maryland

  • White Papers // May 2011

    Analysis of Explanatory and Predictive Architectures and the Relevance in Explaining the Adoption of IT in SMEs

    This paper critiques the explanatory and predictive architectures of six prominent innovation adoption theories with a view to unraveling their individual capabilities in providing lenses to the understanding of the social and idiosyncratic components of Small and Medium Enterprise (SMEs) in adopting Information Technology (IT). The analysis unravels that the...

    Provided By University of Maryland

  • White Papers // May 2011

    Adaptive Transmission Policies for Energy Harvesting Wireless Nodes in Fading Channels

    In this paper, the authors consider a single-user communication system, where an energy harvesting transmitter communicates with a receiver over a fading wireless channel. They design adaptive transmission policies that adapt to the random energy arrivals at the transmitter and random fluctuations in the channel, in order to maximize the...

    Provided By University of Maryland

  • White Papers // May 2011

    LeechLock: Preventing Selfish Clients in the BitTorrent Protocol

    Although the BitTorrent protocol incentivizes sharing by increasing a peer's download rate, tools have demonstrated that the tit-for-tat mechanism alone is insufficient to prevent peers from downloading content without reciprocation. The authors propose an enhancement to the BitTorrent protocol, called Leechlock, which uses globally shared tables to track peers' ratings...

    Provided By University of Maryland

  • White Papers // Apr 2011

    CloudFuice: A flexible Cloud-Based Data Integration System

    The advent of cloud computing technologies shows great promise for web engineering and facilitates the development of flexible, distributed, and scalable web applications. Data integration can notably benefit from cloud computing because integrating web data is usually an expensive task. This paper introduces CloudFuice, a data integration system that follows...

    Provided By University of Maryland

  • White Papers // Apr 2011

    Dynamic Enforcement of Knowledge-Based Security Policies

    This paper explores the idea of knowledge-based security policies, which are used to decide whether to answer queries over secret data based on an estimation of the querier's (possibly increased) knowledge given the results. Limiting knowledge is the goal of existing information release policies that employ mechanisms such as noising,...

    Provided By University of Maryland

  • White Papers // Apr 2011

    Virtual MeshTest - Improving Wireless Network Testbed Using Virtualization and Migration Algorithm

    There are several laboratory-based mobile wireless testbeds such as the MeshTest and the CMU wireless emulator. These testbeds provide powerful computing network platforms for users who want to perform controlled, repeatable, mobile experiments in the lab. However, such systems can only use 10-15 nodes in an experiment. The Virtual Mesh...

    Provided By University of Maryland

  • White Papers // Apr 2011

    Neural Network to Identify Individuals at Health Risk

    The risk of diseases such as heart attack and high blood pressure could be reduced by adequate physical activity. However, even though majority of general population claims to perform some physical exercise, only a minority exercises enough to keep a healthy living style. Thus, physical inactivity has become one of...

    Provided By University of Maryland

  • White Papers // Mar 2011

    Image Ranking and Retrieval Based on Multi-Attribute Queries

    The authors propose a novel approach for ranking and retrieval of images based on multi-attribute queries. Existing image retrieval methods train separate classifiers for each word and heuristically combine their outputs for retrieving multiword queries. Moreover, these approaches also ignore the interdependencies among the query terms. In contrast, they propose...

    Provided By University of Maryland

  • White Papers // Mar 2011

    Constructing Inverted Files on a Cluster of Multicore Processors Near Peak I/O Throughput

    The authors develop a new strategy for processing a collection of documents on a cluster of multicore processors to build the inverted files at almost the peak I/O throughput of the underlying system. The algorithm is based on a number of novel techniques including: A high-throughput pipelined strategy that produces...

    Provided By University of Maryland

  • White Papers // Feb 2011

    Partitioning Detection and Connectivity Restoration Algorithm for Wireless Sensor Actor Networks

    Recently, Wireless Sensor and Actor Networks have been receiving a growing attention from the research community because of their suitability for critical applications. Maintaining inter-actor connectivity becomes extremely crucial in such situations where actors have to quickly plan optimal coordinated response to detected events. Failure of critical actor partitions the...

    Provided By University of Maryland

  • White Papers // Feb 2011

    Managing the Quality of Virtualized Services

    Managing the quality of virtualized services that are delivered on the cloud is very challenging. Such services are often composed of smaller components that are assembled on an as-needed basis. In this paper, the authors propose a framework to measure and semi-automatically track quality delivered by a Virtualized service delivery...

    Provided By University of Maryland

  • White Papers // Jan 2011

    Retrofitting Security in COTS Software With Binary Rewriting

    The authors present a practical tool for inserting security features against low-level software attacks into third-party, proprietary or otherwise binary-only software. They are motivated by the inability of software users to select and use low-overhead protection schemes when source code is unavailable to them, by the lack of information as...

    Provided By University of Maryland

  • White Papers // Jan 2011

    Position Paper: Dynamically Inferred Types for Dynamic Languages

    Over the past few years the authors have been developing Diamondback Ruby (DRuby), a tool that brings static type inference to Ruby, a dynamically typed, object-oriented language. Developing DRuby required creating a Ruby front-end, which was extremely challenging: like other dynamic languages, Ruby has a complex, yet poorly documented syntax...

    Provided By University of Maryland

  • White Papers // Jan 2011

    Using Data for Systemic Financial Risk Management

    The recent financial collapse has laid bare the inadequacies of the information infrastructure supporting the US financial system. Technical challenges around large-scale data systems interact with significant economic forces involving innovation, transparency, confidentiality, complexity, and organizational change, to create a very difficult problem. The post-crisis reform legislation has created a...

    Provided By University of Maryland