139 research outputs found

    Location based mobile computing - a tuplespace perspective

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    This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2006 IOS PressLocation based or "context aware" computing is becoming increasingly recognized as a vital part of a mobile computing environment. As a consequence, the need for location-management middleware is widely recognized and actively researched. Location-management is frequently offered to the application through a "location API" (e.g. JSR 179) where the mobile unit can find out its own location as coordinates or as "building, floor, room" values. It is then up to the application to map the coordinates into a set of localized variables, e.g. direction to the nearest bookshop or the local timezone. It is the opinion of the authors that a localization API should be more transparent and more integrated: The localized values should be handed to the application directly, and the API for doing so should be the same as the general storage mechanisms. Our proposed middleware for location and context management is built on top of Mobispace. Mobispace is a distributed tuplespace made for mobile units (J2me) where replication between local replicas takes place with a central server (over GPRS) or with other mobile units (using Bluetooth). Since a Bluetooth connection indicates physical proximity to another node, a set of stationary nodes may distribute locality information over Bluetooth connections, and this information may be retrieved through the ordinary tuplespace API. Besides the integration with the general framework for communication and coordination the middleware offers straightforward answers to questions like: Where is node X located? Which nodes are near me? What is the trace of node Y

    Game engines and MAS: tuplespace-based interaction in Unity3D

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    I Game Engines stanno acquisendo sempre più importanza sia in ambito industriale, dove permettono lo sviluppo di applicazioni moderne e videogiochi, sia in ambito di ricerca, in particolare nel contesto dei sistemi multi-agente (MAS). La loro capacità espressiva, unita al supporto di tecnologie e funzionalità innovative, permette la creazione di sistemi moderni e complessi in maniera più efficiente: il loro continuo avanzamento tecnologico li ha portati ad essere una realtà su cui fare affidamento nella produzione di vari applicativi diversi, come applicazioni di realtà aumentata/virtuale/mista, simulazioni immersive, costruzione di mondi virtuali e 3D, ecc. Ciononostante, soffrono la mancanza di proprie astrazioni e meccanismi che possano essere affidabili e utilizzati per aggredire la complessità durante il design di sistemi complessi. Il tentativo di sfruttare le caratteristiche della teoria dei MAS all'interno degli ambienti di sviluppo dei Game Engines procede secondo questa direzione: integrando le astrazioni costituenti i MAS all'interno dei Game Engines, con particolare riferimento ai modelli di coordinazione tra agenti, può portare a nuove soluzioni, riuscendo a risolvere problemi tecnologici grazie all'aiuto degli engine grafici. Questa tesi utilizza il Game Engine Unity3D proponendo due librerie C#, le quali sfruttano una precedente integrazione dello stesso framework con il Prolog per l'abilitazione di un modello di interazione e coordinazione basato su spazi di tuple, utilizzabile tramite l'implementazione di primitive LINDA. Le librerie offrono interfacce di programmazione (API) sfruttabili dai programmatori C# Unity3D per integrare nelle loro creazioni il supporto a tale modello, con una nuova modalità per la gestione della coordinazione tra oggetti in Unity3D e fornisce importanti proprietà, essendo fondamentale nel contesto dei MAS dal punto di vista dell'ingegnerizzazione di sistemi complessi e della gestione delle interazioni tra agenti

    HTTP Mailbox - Asynchronous RESTful Communication

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    We describe HTTP Mailbox, a mechanism to enable RESTful HTTP communication in an asynchronous mode with a full range of HTTP methods otherwise unavailable to standard clients and servers. HTTP Mailbox allows for broadcast and multicast semantics via HTTP. We evaluate a reference implementation using ApacheBench (a server stress testing tool) demonstrating high throughput (on 1,000 concurrent requests) and a systemic error rate of 0.01%. Finally, we demonstrate our HTTP Mailbox implementation in a human assisted web preservation application called "Preserve Me".Comment: 13 pages, 6 figures, 8 code blocks, 3 equations, and 3 table

    KLAIM: A Kernel Language for Agents Interaction and Mobility

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    We investigate the issue of designing a kernel programming language for mobile computing and describe KLAIM, a language that supports a programming paradigm where processes, like data, can be moved from one computing environment to another. The language consists of a core Linda with multiple tuple spaces and of a set of operators for building processes. KLAIM naturally supports programming with explicit localities. Localities are first-class data (they can be manipulated like any other data), but the language provides coordination mechanisms to control the interaction protocols among located processes. The formal operational semantics is useful for discussing the design of the language and provides guidelines for implementations. KLAIM is equipped with a type system that statically checks access rights violations of mobile agents. Types are used to describe the intentions (read, write, execute, etc.) of processes in relation to the various localities. The type system is used to determine the operations that processes want to perform at each locality, and to check whether they comply with the declared intentions and whether they have the necessary rights to perform the intended operations at the specific localities. Via a series of examples, we show that many mobile code programming paradigms can be naturally implemented in our kernel language. We also present a prototype implementaton of KLAIM in Java

    TOTAM: Scoped Tuples for the Ambient

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    Coordination of mobile applications posses a number of issues. Devices should be able to communicate with each other without being connected with each other at the same time while maintaining privacy and limited network traffic. Current tuple based approaches solve these issues partially but none of them solves all of them. We propose a novel tuple space-based approach where tuple spaces are annotated with tuple space descriptors used to determine the scope of a tuple. The novelty of our approach lies in the use of these tuple space descriptors to determine that a tuple should be propagated before it is transmitted. This enhances privacy and decreases the burden on the network traffic in a wide range of applications
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