Association for Computing Machinery

Displaying 5961-6000 of 6273 results

  • White Papers // Jun 2008

    Event-Triggered Location Aware Data Services in Mobile WSNs

    Mobile Wireless Sensor Networks (WSNs) are increasingly deployed in many applications to provide various data services to users. However, existing data service approaches are incapable of efficiently answering some complicated queries in mobile WSNs. In this paper, the authors propose a new event-triggered query model which generalizes many location aware...

    Provided By Association for Computing Machinery

  • White Papers // Jun 2008

    The Second Life of a Sensor: Integrating Real-World Experience in Virtual Worlds Using Mobile Phones

    Virtual world simulators represent one of the latest and most successful frontiers of online entertainment. Among them, Second Life is one of the most popular Internet based virtual worlds in terms of subscribers with over 500,000 active users. A client program called the Second Life Viewer allows its users (Called...

    Provided By Association for Computing Machinery

  • White Papers // Jun 2008

    Mesh Technology Enabling Ubiquitous Wireless Networks

    Today's wireless networking technology provides high data rates. With IEEE 802.11n products, data rates beyond 500 Mb/s are soon feasible for Wireless Local Area Network (WLAN). Due to a standstill in standardization the project IEEE 802.15.3a it was disbanded in 2006. Companies are pushing therefore their own solutions to the...

    Provided By Association for Computing Machinery

  • White Papers // Jun 2008

    Approximate Continuous Querying Over Distributed Streams

    While traditional database systems optimize for performance on one-shot query processing, emerging large-scale monitoring applications require continuous tracking of complex data-analysis queries over collections of physically distributed streams. Thus, effective solutions have to be simultaneously space/time efficient (at each remote monitor site), communication efficient (across the underlying communication network), and...

    Provided By Association for Computing Machinery

  • White Papers // Jun 2008

    The Impact of Spatial Correlation on Routing With Compression in Wireless Sensor Networks

    The efficacy of data aggregation in sensor networks is a function of the degree of spatial correlation in the sensed phenomenon. The recent literature has examined a variety of schemes that achieve greater data aggregation by routing data with regard to the underlying spatial correlation. A well known conclusion from...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Dynamic Routing of Reliability-Differentiated Connections in Optical Burst Switched Networks

    Optical Burst Switching (OBS) is one of the most promising next-generation all-optical data transport paradigms. As networks become increasingly distributed and autonomic, Optical Burst Switching becomes the right choice for the next generation optical Internet. In this paper, the authors propose a mechanism for Dynamic Routing of Reliability-Differentiated Connections (DRRDC)...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Strong Barrier Coverage of Wireless Sensor Networks

    Constructing sensor barriers to detect intruders crossing a randomly-deployed sensor network is an important problem. Early results have shown how to construct sensor barriers to detect intruders moving along restricted crossing paths in rectangular areas. This paper presents a complete solution to this problem for sensors that are distributed according...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Teaching Programming Languages in a Post-Linnaean Age

    Programming language "Paradigms" are a moribund and tedious legacy of a bygone age. Modern language designers pay them no respect, so why does the courses slavishly adhere to them? This paper argues that one should abandon this method of teaching languages, offers an alternative, reconciles an important split in programming...

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  • White Papers // May 2008

    Towards Energy Efficient VoIP Over Wireless LANs

    Wireless LAN (WLAN) radios conserve energy by staying in sleep mode. With real-time applications like VoIP, it is not clear how much energy can be saved by this approach since packets delayed above a threshold are lost. In this work the author proposes the GreenCall algorithm to derive sleep/wakeup schedules...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Finding Popular Categories for RFID Tags

    As RFID tags are increasingly attached to everyday items, it quickly becomes impractical to collect data from every tag in order to extract useful information. In this paper, the authors consider the problem of identifying popular categories of RFID tags out of a large collection of tags, without reading all...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Opportunistic and Cooperative Spatial Multiplexing in MIMO Ad Hoc Networks

    It is important and challenging to develop efficient schemes to coordinate node transmissions in a MIMO-based ad hoc network. In this work, the authors propose a scheme to fully exploit the multiuser diversity and spatial diversity by taking advantage of the meshed topology, while also supporting user transmission quality requirement....

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  • White Papers // May 2008

    Analyzing DISH for Multi-Channel MAC Protocols in Wireless Networks

    For long, node cooperation has been exploited as a data relaying mechanism. However, the wireless channel allows for much richer interaction between nodes. One such scenario is in a multi-channel environment, where transmitter-receiver pairs may make incorrect decisions (e.g., in selecting channels) but idle neighbors could help by sharing information...

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  • White Papers // May 2008

    Improving Sensor Network Immunity Under Worm Attacks: A Software Diversity Approach

    Because of cost and resource constraints, sensor nodes do not have a complicated hardware architecture or operating system to protect program safety. Hence, the notorious buffer-overflow vulnerability that has caused numerous Internet worm attacks could also be exploited to attack sensor networks. The authors call the malicious code that exploits...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    The Capacity and Energy Efficiency of Wireless Ad Hoc Networks With Multi-Packet Reception

    The seminal work by Gupta and Kumar on the scaling laws of wireless ad hoc networks, show that forwarding information from sources to destinations over multihop paths in which each relay is able to transmit or receive at most one packet at a time is not scalable. As a result,...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Mixed Altruistic and Selfish Users in Wireless Mesh Networks: A Game Theoretic Model for Multihop Bandwidth Sharing

    Mesh networking is a feasible and effective way to route between nodes. The reliability and versatility of wireless mesh networks makes it a critical part of the future Wireless Internet. The authors apply a tree routing structure to formulate the multihop relay system topology. Wireless mesh network has a gateway...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    An O(log N) Dominating Set Protocol for Wireless AdHoc Networks Under the Physical Interference Model

    Dealing with interference is one of the primary challenges to solve in the design of protocols for wireless ad-hoc networks. Most of the work in the literature assumes localized or hop-based interference models in which the effect of interference is neglected beyond a certain range from the transmitter. However, interference...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    An Approximation Algorithm for Conflict-Aware Broadcast Scheduling in Wireless Ad Hoc Networks

    Broadcast scheduling is a fundamental problem in wireless ad hoc networks. The objective of a broadcast schedule is to deliver a message from a given source to all other nodes in a minimum amount of time. At the same time, in order for the broadcast to proceed as predicted in...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Complexity in Wireless Scheduling: Impact and Tradeoffs

    It has been an important research topic since 1992 to maximize stability region in constrained queueing systems, which includes the study of scheduling over wireless ad hoc networks. In this paper, the authors propose a framework to study a wide range of existing and future scheduling algorithms and characterize the...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Challenging Benchmark for Location Discovery in Ad Hoc Networks: Foundations and Applications

    The authors have created the first comprehensive and challenging benchmark data set for the ad-hoc Location Discovery (LD). The benchmark is a collection of representative real-life distance measurement data that establishes a common basis for understanding, characterization, evaluation and comparison of the LD algorithms and solvers. It is constructed using...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Rendezvous Design Algorithms for Wireless Sensor Networks With a Mobile Base Station

    Recent research shows that significant energy saving can be achieved in wireless sensor networks with a mobile base station that collects data from sensor nodes via short-range communications. However, a major performance bottleneck of such WSNs is the significantly increased latency in data collection due to the low movement speed...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Dice: A Game Theoretic Framework for Wireless Multipath Network Coding

    Network coding has emerged as a promising approach that enables reliable and efficient end-to-end transmissions in lossy wireless mesh networks. Existing protocols have demonstrated its resilience to packet losses, as well as the ability to integrate naturally with multipath opportunistic routing. However, these heuristics do not take into account the...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Construction Algorithms for k-Connected m-Dominating Sets in Wireless Sensor Networks

    A Connected Dominating Set (CDS) working as a virtual backbone is an effective way to decrease the overhead of routing in a wireless sensor network. Furthermore, a k-Connected m-Dominating Set (kmCDS) is necessary for fault tolerance and routing flexibility. Some approximation algorithms have been proposed to construct a kmCDS. However,...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Delay-Bounded Routing in Vehicular Ad-Hoc Networks

    Ad hoc networks formed by traveling vehicles are envisaged to become a common platform that will support a wide variety of applications, ranging from road safety to advertising and entertainment. The multitude of vehicular applications calls for routing schemes that satisfy user-defined delay requirements while at the same time maintaining...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Toward Stochastic Anatomy of Inter-Meeting Time Distribution Under General Mobility Models

    Recent discovery of the mixture (power-law and exponential) behavior of inter-meeting time distribution of mobile nodes presents new challenge to the problem of mobility modeling and its effect on the network performance. Existing studies on this problem via the average inter-meeting time become insufficient when the inter-meeting time distribution starts...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Energy Efficient Multi-Path Communication for Time-Critical Applications in Underwater Sensor Networks

    Due to the long propagation delay and high error rate of acoustic channels, it is very challenging to provide reliable data transfer for time-critical applications in an energy-efficient way. On the one hand, traditional retransmission-upon-failure usually introduces very large end-to-end delay, thus is not proper for time-critical services. On the...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Hidden Information and Actions in Multi-Hop Wireless Ad Hoc Networks

    For multi-hop ad hoc networks formed by individually owned nodes, the endpoints can only observe whether or not the end-to-end transaction was successful or not, but not the individual actions of intermediate nodes. Consequently, in the absence of properly designed incentive schemes, rational (i.e., selfish) intermediate nodes may choose to...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Optimal Relay Assignment for Cooperative Communications

    Recently, cooperative communications, in the form of keeping each node with a single antenna and having a node exploit a relay node's antenna, is shown to be a promising approach to achieve spatial diversity. Under this communication paradigm, the choice of relay node plays a significant role in the overall...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Routing in a Cyclic MobiSpace

    A key challenge of routing in Delay Tolerant Networks (DTNs) is to find routes that have high delivery rates and low end-to-end delays. When oracles are not available for future connectivity, opportunistic routing is preferred in DTNs, in which messages are forwarded to nodes with higher delivery probabilities. The authors...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Poster Abstract: Force-Based Geometric Routing

    Routing is the foremost issue in Mobile Ad hoc NETworks (MANETs) and sensor networks. To guarantee delivery and improve performance, most position-based routing protocols are based on face routing, which requires the underlying network to be a planar graph. Localized planar graph construction requires the radio model to be a...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    A Game Approach for Multi-Channel Allocation in Multi-Hop Wireless Networks

    Channel allocation was extensively investigated in the framework of cellular networks, but it was rarely studied in the wireless ad-hoc networks, especially in the multi-hop ad-hoc networks. In this paper, the authors study the competitive multi-radio channel allocation problem in multi-hop wireless networks in detail. They model the channel allocation...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    On Exploiting Diversity and Spatial Reuse in Relay-Enabled Wireless Networks

    Relay-enabled wireless networks (eg. WIMAX 802.16j) represent an emerging trend for the incorporation of multi-hop networking solutions for last-mile broadband access in next generation wireless networks. The adoption of more sophisticated access technologies such as OFDM (Orthogonal Frequency Division Multiplexing) coupled with the relay-induced two-hop nature, provides two key benefits...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Route Recovery in Vertex-Disjoint Multipath Routing for Many-to-One Sensor Networks

    Multipath routing is attractive for load-balancing, fault-tolerance, and security enhancement. However, constructing and maintaining a set of node-disjoint paths between the data source and sink is non-trivial in a dynamic environment. In this paper, the authors study the problem of route recovery in vertex-disjoint multipath routing for sensor networks with...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Fast and Quality-Guaranteed Data Streaming in Resource-Constrained Sensor Networks

    In many emerging applications, data streams are monitored in a network environment. Due to limited communication bandwidth and other resource constraints, a critical and practical demand is to online compress data streams continuously with quality guarantee. Although many data compression and digital signal processing methods have been developed to reduce...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Delegation Forwarding

    Mobile opportunistic networks are characterized by unpredictable mobility, heterogeneity of contact rates and lack of global information. Successful delivery of messages at low costs and delays in such networks is thus challenging. Most forwarding algorithms avoid the cost associated with flooding the network by forwarding only to nodes that are...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    The Networking Shape of Vehicular Mobility

    Mobility is the distinguishing feature of vehicular networks, affecting the evolution of network connectivity over space and time in a unique way. Connectivity dynamics, in turn, determine the performance of networking protocols, when they are employed in vehicle-based, large-scale communication systems. Thus, a key question in vehicular networking is: which...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Position Paper: Practical Foundations for Programming Languages

    A program is a form of expression that conveys an idea, much as does a proof in mathematics. But whereas proofs have only a static significance, as a form of communication, programs also have a dynamic significance, as commands to be executed by a machine. This places very strong demands...

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  • White Papers // May 2008

    Characterizing 802.11 Wireless Link Behavior

    Since wireless signals propagate through the ether, they are significantly affected by attenuation, fading, multipath, and interference. As a result, it is difficult to measure and understand fundamental wireless network behavior. This creates a challenge for both network researchers, who often rely on simulators to evaluate their work, and network...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Query Distribution Estimation and Predictive Caching in Mobile Ad Hoc Networks

    The problem of data management has been studied widely in the field of mobile ad-hoc networks and pervasive computing. The issue addressed is that finding the data required by a device depends on chance encounter with the source of data. Most existing research has focused on specifying the required data...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Routing Performance Analysis of Human-Driven Delay Tolerant Networks Using the Truncated Levy Walk Model

    The routing performance of Delay Tolerant Networks (DTN) is highly correlated with the distribution of Inter-Contact Times (ICT), the time-period between two successive contacts of the same two mobile nodes. As humans are of-ten carriers of mobile communication devices, studying the patterns of human mobility is an essential tool to...

    Provided By Association for Computing Machinery

  • White Papers // May 2008

    Generic Mobility Simulation Framework (GMSF)

    Vehicular ad-hoc networks with inter-vehicular communications are a prospective technology which contributes to safer and more efficient roads and offers information and entertainment services to mobile users. Since large real-world testbeds are not feasible, research on vehicular ad-hoc networks depends mainly on simulations. Therefore, it is crucial that realistic mobility...

    Provided By Association for Computing Machinery

  • White Papers // Jan 2009

    Abstraction-Guided Synthesis of Synchronization

    The authors present a novel framework for automatic inference of efficient synchronization in concurrent programs, a task known to be difficult and error-prone when done manually. Their framework is based on abstract interpretation and can infer synchronization for infinite state programs. Given a program, a specification, and an abstraction, they...

    Provided By Association for Computing Machinery

  • White Papers // May 2010

    Verifying Safety Properties of Concurrent Heap-Manipulating Programs

    The authors provide a parametric framework for verifying safety properties of concurrent heap-manipulating programs. The framework combines thread-scheduling information with information about the shape of the heap. This leads to verification algorithms that are more precise than existing techniques. The framework also provides a precise shape-analysis algorithm for concurrent programs....

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  • White Papers // Jan 2010

    Static Determination of Quantitative Resource Usage for Higher-Order Programs

    The authors describe a new automatic static analysis for determining upper-bound functions on the use of quantitative resources for strict, higher-order, polymorphic, recursive programs dealing with possibly-aliased data. Their analysis is a variant of Tarjan's manual amortised cost analysis technique. They use a type-based approach, exploiting linearity to allow inference,...

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  • White Papers // Oct 2011

    Growing a Language Environment With Editor Libraries

    Large software projects consist of code written in a multitude of different (possibly domain-specific) languages, which are often deeply interspersed even in single files. While many proposals exist on how to integrate languages semantically and syntactically, the question of how to support this scenario in Integrated Development Environments (IDEs) remains...

    Provided By Association for Computing Machinery

  • White Papers // Aug 2011

    The Road to Feature Modularity

    Modularity of feature representations has been a long standing goal of feature-oriented software development. While some researchers regard feature modules and corresponding composition mechanisms as a modular solution, other researchers have challenged the notion of feature modularity and pointed out that most feature-oriented implementation mechanisms lack proper interfaces and support...

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  • White Papers // Oct 2011

    Variability-Aware Parsing in the Presence of Lexical Macros and Conditional Compilation

    In many projects, lexical pre-processors are used to manage different variants of the project (using conditional compilation) and to define compile-time code transformations (using macros). Unfortunately, while being a simple way to implement variability, conditional compilation and lexical macros hinder automatic analysis, even though such analysis is urgently needed to...

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  • White Papers // Oct 2011

    SugarJ: Library-Based Syntactic Language Extensibility

    Existing approaches to extend a programming language with syntactic sugar often leave a bitter taste, because they cannot be used with the same ease as the main extension mechanism of the programming language-libraries. Sugar libraries are a novel approach for syntactically extending a programming language within the language. A sugar...

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  • White Papers // Jun 2011

    Synchronization via Scheduling: Techniques For Efficiently Managing Shared State

    Shared state access conflicts are one of the greatest sources of error for fine grained parallelism in any domain. Notoriously hard to debug, these conflicts reduce reliability and increase development time. The standard task graph model dictates that tasks with potential conflicting accesses to shared state must be linked by...

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  • White Papers // Mar 2011

    Global Cost Diversity Aware Dispatch Algorithm for Heterogeneous Data Centers

    Large, Internet based companies service user requests from multiple data centers located across the globe. These data centers often house a heterogeneous computing infrastructure and draw electricity from the local electricity market. Reducing the electricity costs of operating these data centers is a challenging problem, and in this paper, the...

    Provided By Association for Computing Machinery

  • White Papers // May 2011

    FACT: A Framework for Adaptive Contention-Aware Thread Migrations

    Thread scheduling in multi-core systems is a challenging problem because cores on a single chip usually share parts of the memory hierarchy, such as last-level caches, prefetchers and memory controllers, making threads running on different cores interfere with each other while competing for these resources. Data center service providers are...

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  • White Papers // Sep 2010

    AKULA: A Toolset for Experimenting and Developing Thread Placement Algorithms on Multicore Systems

    Multi-core processors have become commonplace in both desktop and servers. A serious challenge with multi-core processors is that cores share on and off chip resources such as caches, memory buses, and memory controllers. Competition for these shared resources between threads running on different cores can result in severe and unpredictable...

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  • White Papers // May 2010

    Operating System Support for Mitigating Software Scalability Bottlenecks on Asymmetric Multicore Processors

    Asymmetric Multi-core Processors (AMP) promise higher performance per watt than their symmetric counterparts, and it is likely that future processors will integrate a few fast out-of-order cores, coupled with a large number of simpler, slow cores, all exposing the same Instruction-Set Architecture (ISA). It is well known that one of...

    Provided By Association for Computing Machinery

  • White Papers // Oct 2011

    Preliminary Design of the SAFE Platform

    Safe is a clean-slate design for a secure host architecture. It integrates advances in programming languages, operating systems, and hardware and incorporates formal methods at every step. Though the project is still at an early stage, the authors have assembled a set of basic architectural choices that they believe will...

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  • White Papers // Oct 2008

    Linear Time Membership in a Class of Regular Expressions With Interleaving and Counting

    The extension of Regular Expressions (REs) with an inter-leaving (shuffle) operator has been proposed in many occasions, since it would be crucial to deal with unordered data. However, interleaving badly affects the complexity of basic operations, and, especially, makes membership NP- hard, which is unacceptable for most uses of REs....

    Provided By Association for Computing Machinery

  • White Papers // Oct 2011

    Adaptation-Based Programming in Java

    Writing deterministic programs is often difficult for problems whose optimal solutions depend on unpredictable properties of the programs' inputs. Difficulty is also encountered for problems where the programmer is uncertain about how to best implement certain aspects of a solution. For such problems a mixed strategy of deterministic programming and...

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  • White Papers // Jan 2012

    Representation Systems for Data Exchange

    The notion of representation systems describes structures that are algebraically closed under queries. It has recently been realized that representation systems are highly relevant also in the context of data exchange. The authors extend the notion of representation system to encompass data exchange map-pings and their composition. Seen through this...

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  • White Papers // Mar 2010

    Data Correspondence, Exchange and Repair

    Checking the correspondence between two or more database instances and enforcing it is a procedure widely used in practice without however having been explored from a theoretical perspective. In this paper, the authors formally introduce the data correspondence setting and its associated computational problems: checking the existence of solutions, and...

    Provided By Association for Computing Machinery

  • White Papers // Mar 2011

    Closed World Chasing

    The authors give a new closed world semantics for data exchange called constructible solutions semantics, and argue that this semantics is well suited for answering non-monotonic queries in data exchange. They show that the space of constructible solutions can be represented by conditional tables obtainable trough a novel conditional chase...

    Provided By Association for Computing Machinery

  • White Papers // May 2011

    Model Projection: Simplifying Models in Response to Restricting the Environment

    This paper introduces Model Projection. Finite state models such as Extended Finite State Machines are being used in an ever increasing number of software engineering activities. Model projection facilitates model development by specializing models for a specific operating environment. A projection is useful in many design-level applications including specification reuse...

    Provided By Association for Computing Machinery

  • White Papers // Nov 2011

    BNF WAS HERE: What Have We Done About the Unnecessary Diversity of Notation for Syntactic Definitions

    Reusing existing grammar knowledge residing in standards, specifications and manuals for programming languages, faces several challenges. One of the most significant of them is the diversity of syntactic notations: without loss of generality, the authors can state that every single language document uses its own notation, which is more often...

    Provided By Association for Computing Machinery

  • White Papers // May 2010

    Secure Information Flow Analysis for Hardware Design: Using the Right Abstraction for the Job

    Hardware designers need to precisely analyze high-level descriptions for illegal information flows. Language-based information flow analysis can be applied to hardware description languages, but a straight-forward application either conservatively rules out many secure hardware designs, or constrains the designers to work at impractically low levels of abstraction. The authors demonstrate...

    Provided By Association for Computing Machinery

  • White Papers // Jul 2008

    Implementing Fault-Tolerance in Real-Time Programs by Automatic Program Transformations

    The authors present a formal approach to implement fault-tolerance in real-time embedded systems. The initial fault-intolerant system consists of a set of independent periodic tasks scheduled onto a set of fail-silent processors connected by a reliable communication network. They transform the tasks such that, assuming the availability of an additional...

    Provided By Association for Computing Machinery

  • White Papers // Oct 2011

    PREFAIL: A Programmable Tool for Multiple-Failure Injection

    As hardware failures are no longer rare in the era of cloud computing, cloud software systems must "Prevail" against multiple, diverse failures that are likely to occur. Testing software against multiple failures poses the problem of combinatorial explosion of multiple failures. To address this problem, the authors present PreFail, a...

    Provided By Association for Computing Machinery

  • White Papers // Nov 2011

    Efficient Data Race Detection for Distributed Memory Parallel Programs

    In this paper, the authors present a precise data race detection technique for distributed memory parallel programs. The authors' technique, which they call Active Testing, builds on their previous work on race detection for shared memory Java and C programs and it handles programs written using shared memory approaches as...

    Provided By Association for Computing Machinery

  • White Papers // Jun 2011

    NDSeq: Runtime Checking for Nondeterministic Sequential Specifications of Parallel Correctness

    The authors propose to specify the correctness of a program's parallelism using a sequential version of the program with controlled non-determinism. Such a non-deterministic sequential specification allows the correctness of parallel interference to be verified independently of the program's functional correctness, and the functional correctness of a program to be...

    Provided By Association for Computing Machinery

  • White Papers // May 2011

    Symbolic Execution for Software Testing in Practice - Preliminary Assessment

    The authors present results for the "Impact Project Focus Area" on the topic of symbolic execution as used in software testing. Symbolic execution is a program analysis technique introduced in the 70s that has received renewed interest in recent years, due to algorithmic advances and increased availability of computational power...

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  • White Papers // Mar 2011

    Specifying and Checking Semantic Atomicity for Multithreaded Programs

    In practice, it is quite difficult to write correct multi-threaded programs due to the potential for unintended and non-deterministic interference between parallel threads. A fundamental correctness property for such programs is atomicity - a block of code in a program is atomic if, for any parallel execution of the program,...

    Provided By Association for Computing Machinery

  • White Papers // Jul 2011

    Testing Concurrent Programs on Relaxed Memory Models

    High-performance concurrent libraries, such as lock-free data structures and custom synchronization primitives, are notoriously difficult to write correctly. Such code is often implemented without locks, instead using plain loads and stores and low-level operations like atomic compare-and-swaps and explicit memory fences. Such code must run correctly despite the relaxed memory...

    Provided By Association for Computing Machinery

  • White Papers // Nov 2010

    A Trace Simplification Technique for Effective Debugging of Concurrent Programs

    Concurrent programs are notoriously difficult to debug. The authors see two main reasons for this: concurrency bugs are often difficult to reproduce, traces of buggy concurrent executions can be complicated by fine-grained thread interleavings. Recently, a number of efficient techniques have tried to address the former reproducibility problem; however, there...

    Provided By Association for Computing Machinery

  • White Papers // Aug 2009

    Asserting and Checking Determinism for Multithreaded Programs

    The trend towards processors with more and more parallel cores is increasing the need for software that can take advantage of parallelism. The most widespread method for writing parallel software is to use explicit threads. Writing correct multi-threaded programs, however, has proven to be quite challenging in practice. The key...

    Provided By Association for Computing Machinery

  • White Papers // Jun 2009

    A Randomized Dynamic Program Analysis Technique for Detecting Real Deadlocks

    The authors present a novel dynamic analysis technique that finds real deadlocks in multi-threaded programs. Their technique runs in two stages. In the first stage, they use an imprecise dynamic analysis technique to find potential deadlocks in a multi-threaded program by observing an execution of the program. In the second...

    Provided By Association for Computing Machinery

  • White Papers // Oct 2010

    Efficient Modular Glass Box Software Model Checking

    Glass box software model checking incorporates novel techniques to identify similarities in the state space of a model checker and safely prune large numbers of redundant states without explicitly checking them. It is significantly more efficient than other software model checking approaches for checking certain kinds of programs and program...

    Provided By Association for Computing Machinery

  • White Papers // Oct 2008

    Efficient Software Model Checking of Soundness of Type Systems

    This paper presents novel techniques for checking the soundness of a type system automatically using a software model checker. The authors' idea is to systematically generate every type correct intermediate program state (within some finite bounds), execute the program one step forward if possible using its small step operational semantics,...

    Provided By Association for Computing Machinery

  • White Papers // Jun 2011

    Handles Revisited: Optimising Performance and Memory Costs in a Real-Time Collector

    Compacting garbage collectors must update all references to objects they move. Updating is a lengthy operation but the updates must be transparent to the mutator. The consequence is that no space can be reclaimed until all references have been updated which, in a real-time collector, must be done incrementally. One...

    Provided By Association for Computing Machinery

  • White Papers // Jan 2011

    A Semantics for Lazy Assertions

    Lazy functional programming languages need lazy assertions to ensure that assertions preserve the meaning of programs. Examples in this paper demonstrate that previously proposed lazy assertions nonetheless break basic semantic equivalences, because they include a non-deterministic disjunction combinator. The objective of this paper is to determine "Correct" definitions for lazy...

    Provided By Association for Computing Machinery

  • White Papers // Apr 2010

    Santa Claus: Formal Analysis of a Process-Oriented Solution

    With the commercial development of multi-core processors, the challenges of writing multi-threaded programs to take advantage of these new hardware architectures are becoming more and more pertinent. Concurrent programming is necessary to achieve the performance that the hardware offers. Traditional approaches present concurrency as an advanced topic: they have proven...

    Provided By Association for Computing Machinery

  • White Papers // Feb 2011

    End-User Feature Labeling: A Locally-Weighted Regression Approach

    When intelligent interfaces, such as intelligent desktop assistants, email classifiers, and recommender systems, customize themselves to a particular end user, such customizations can decrease productivity and increase frustration due to inaccurate predictions - especially in early stages, when training data is limited. The end user can improve the learning algorithm...

    Provided By Association for Computing Machinery

  • White Papers // May 2010

    A Visual Tool for Using Design Patterns as Pattern Languages

    Design patterns document successful solutions to recurrent problems in a specific software development domain. However, finding the patterns one need can be difficult, often requiring the designer to comprehend a long narrative description to understand the benefits, implications and trade-offs of each pattern and of its relationships with others. In...

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  • White Papers // Jul 2010

    Factors Affecting the Use of Genetic Algorithms in Test Suite Augmentation

    Test suite augmentation techniques are used in regression testing to help engineers identify code elements affected by changes, and generate test cases to cover those elements. Researchers have created various approaches to identify affected code elements, but only recently have they considered integrating, with this task, approaches for generating test...

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  • White Papers // Aug 2011

    Trouble Shooting Interactive Web Sessions in a Home Environment

    Home clients can use their access to the Internet for different purposes such as file sharing via P2P applications, gaming, or Web browsing; the last one is the focus of this work. When browsing the Web, the time elapsed between the click on a URL and the rendering of the...

    Provided By Association for Computing Machinery