25,970 research outputs found

    WWW Programming using computational logic systems (and the PiLLoW/Ciao library)

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    We discuss from a practical point of view a number of issues involved in writing Internet and WWW applications using LP/CLP systems. We describe Pd_l_oW, a public-domain Internet and WWW programming library for LP/CLP systems which we argüe significantly simplifies the process of writing such applications. Pd_l_oW provides facilities for generating HTML structured documents, producing HTML forms, writing form handlers, accessing and parsing WWW documents, and accessing code posted at HTTP addresses. We also describe the architecture of some application classes, using a high-level model of client-server interaction, active modules. We then propose an architecture for automatic LP/CLP code downloading for local execution, using generic browsers. Finally, we also provide an overview of related work on the topic. The PiLLoW library has been developed in the context of the &- Prolog and CIAO systems, but it has been adapted to a number of popular LP/CLP systems, supporting most of its functionality

    Shared visiting in Equator city

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    In this paper we describe an infrastructure and prototype system for sharing of visiting experiences across multiple media. The prototype supports synchronous co-visiting by physical and digital visitors, with digital access via either the World Wide Web or 3-dimensional graphics

    On Asynchronous Session Semantics

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    This paper studies a behavioural theory of the π-calculus with session types under the fundamental principles of the practice of distributed computing — asynchronous communication which is order-preserving inside each connection (session), augmented with asynchronous inspection of events (message arrivals). A new theory of bisimulations is introduced, distinct from either standard asynchronous or synchronous bisimilarity, accurately capturing the semantic nature of session-based asynchronously communicating processes augmented with event primitives. The bisimilarity coincides with the reduction-closed barbed congruence. We examine its properties and compare them with existing semantics. Using the behavioural theory, we verify that the program transformation of multithreaded into event-driven session based processes, using Lauer-Needham duality, is type and semantic preserving

    Structural health monitoring through dense instrumentation by community participants: the Community Seismic Network and Quake-Catcher Network

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    The Community Seismic Network and Quake-Catcher Network involve participants from communities at large to install low-cost accelerometers in houses and buildings for assessment of shaking intensity due to earthquakes. The seismometers are designed for two types of connec-tions: a USB-connected device which connects to the host’s computer, and a stand-alone sensor-plug-computer device that directly connects to the internet. The three-component sensors report both continuous data and amplitude anomalies in local acceleration to a Cloud computing service consisting of data centers geographically distributed across the continent, or to a distributed computing system. The continuous time series waveform data are being used to evaluate response parameters such as peak acceleration, peak velocity, and inter-story drift values. In addition, modal properties such as fundamental and higher mode frequencies and mode shapes are being computed from small and moderate earthquake data from the building. Building motion is computed for every floor of the building using only earthquake records from a single floor. Visualization models that map the instrumented buildings’ responses have been construct-ed using SketchUp and an associated plug-in to Matlab with recorded shaking data. This data visualization approach is different from other techniques because each building model is customized to show actual data recorded from that building on varying spatial scales, without the need for large-scale parallel computing facilities or complicated software that requires a steep learning curve

    Blackboard Rules for Coordinating Context-aware Applications in Mobile Ad Hoc Networks

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    Thanks to improvements in wireless communication technologies and increasing computing power in hand-held devices, mobile ad hoc networks are becoming an ever-more present reality. Coordination languages are expected to become important means in supporting this type of interaction. To this extent we argue the interest of the Bach coordination language as a middleware that can handle and react to context changes as well as cope with unpredictable physical interruptions that occur in opportunistic network connections. More concretely, our proposal is based on blackboard rules that model declaratively the actions to be taken once the blackboard content reaches a predefined state, but also that manage the engagement and disengagement of hosts and transient sharing of blackboards. The idea of reactiveness has already been introduced in previous work, but as will be appreciated by the reader, this article presents a new perspective, more focused on a declarative setting.Comment: In Proceedings FOCLASA 2012, arXiv:1208.432
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