32,290 research outputs found

    A distributed Real-Time Java system based on CSP

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    CSP is a fundamental concept for developing software for distributed real time systems. The CSP paradigm constitutes a natural addition to object orientation and offers higher order multithreading constructs. The CSP channel concept that has been implemented in Java deals with single- and multi-processor environments and also takes care of the real time priority scheduling requirements. For this, the notion of priority and scheduling has been carefully examined and as a result it was reasoned that priority scheduling should be attached to the communicating channels rather than to the processes. In association with channels, a priority based parallel construct is developed for composing processes: hiding threads and priority indexing from the user. This approach simplifies the use of priorities for the object oriented paradigm. Moreover, in the proposed system, the notion of scheduling is no longer connected to the operating system but has become part of the application instead

    PALS/PRISM Software Design Description (SDD): Ver. 0.51

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    This Software Design Description (SDD) provides detailed information on the architecture and coding for the PRISM C++ library (version 0.51). The PRISM C++ library supports consistent information sharing and in- teractions between distributed components of networked embedded systems, e.g. avionics. It is designed to reduce the complexity of the networked sys- tem by employing synchronous semantics provided by the architectural pat- tern called a Physically-Asynchronous Logically-Synchronous (PALS) system.unpublishednot peer reviewe

    Predictable migration and communication in the Quest-V multikernal

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    Quest-V is a system we have been developing from the ground up, with objectives focusing on safety, predictability and efficiency. It is designed to work on emerging multicore processors with hardware virtualization support. Quest-V is implemented as a ``distributed system on a chip'' and comprises multiple sandbox kernels. Sandbox kernels are isolated from one another in separate regions of physical memory, having access to a subset of processing cores and I/O devices. This partitioning prevents system failures in one sandbox affecting the operation of other sandboxes. Shared memory channels managed by system monitors enable inter-sandbox communication. The distributed nature of Quest-V means each sandbox has a separate physical clock, with all event timings being managed by per-core local timers. Each sandbox is responsible for its own scheduling and I/O management, without requiring intervention of a hypervisor. In this paper, we formulate bounds on inter-sandbox communication in the absence of a global scheduler or global system clock. We also describe how address space migration between sandboxes can be guaranteed without violating service constraints. Experimental results on a working system show the conditions under which Quest-V performs real-time communication and migration.National Science Foundation (1117025

    Intelligent Integrated Management for Telecommunication Networks

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    As the size of communication networks keeps on growing, faster connections, cooperating technologies and the divergence of equipment and data communications, the management of the resulting networks gets additional important and time-critical. More advanced tools are needed to support this activity. In this article we describe the design and implementation of a management platform using Artificial Intelligent reasoning technique. For this goal we make use of an expert system. This study focuses on an intelligent framework and a language for formalizing knowledge management descriptions and combining them with existing OSI management model. We propose a new paradigm where the intelligent network management is integrated into the conceptual repository of management information called Managed Information Base (MIB). This paper outlines the development of an expert system prototype based in our propose GDMO+ standard and describes the most important facets, advantages and drawbacks that were found after prototyping our proposal

    Timed Automata Semantics for Analyzing Creol

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    We give a real-time semantics for the concurrent, object-oriented modeling language Creol, by mapping Creol processes to a network of timed automata. We can use our semantics to verify real time properties of Creol objects, in particular to see whether processes can be scheduled correctly and meet their end-to-end deadlines. Real-time Creol can be useful for analyzing, for instance, abstract models of multi-core embedded systems. We show how analysis can be done in Uppaal.Comment: In Proceedings FOCLASA 2010, arXiv:1007.499

    A distributed agent architecture for real-time knowledge-based systems: Real-time expert systems project, phase 1

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    We propose a distributed agent architecture (DAA) that can support a variety of paradigms based on both traditional real-time computing and artificial intelligence. DAA consists of distributed agents that are classified into two categories: reactive and cognitive. Reactive agents can be implemented directly in Ada to meet hard real-time requirements and be deployed on on-board embedded processors. A traditional real-time computing methodology under consideration is the rate monotonic theory that can guarantee schedulability based on analytical methods. AI techniques under consideration for reactive agents are approximate or anytime reasoning that can be implemented using Bayesian belief networks as in Guardian. Cognitive agents are traditional expert systems that can be implemented in ART-Ada to meet soft real-time requirements. During the initial design of cognitive agents, it is critical to consider the migration path that would allow initial deployment on ground-based workstations with eventual deployment on on-board processors. ART-Ada technology enables this migration while Lisp-based technologies make it difficult if not impossible. In addition to reactive and cognitive agents, a meta-level agent would be needed to coordinate multiple agents and to provide meta-level control
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