Middleware is increasingly being used to develop and deploy components in large-scale distributed real-time and embedded (DRE) systems, such as the proposed NASA sensor web composed of networked remote sensing satellites, atmospheric, oceanic, and terrestrial sensors. Such a system must perform sequences of autonomous coordination and heterogeneous data manipulation tasks to meet specified goals. For example, accurate weather prediction requires multiple satellites that fly coordinated missions to collect and analyze large quantities of atmospheric and earth surface data. The efficacy and utility of the task sequences are governed by dynamic factors, such as data analysis results, changing goals and priorities, and uncertainties due to changing environmental conditions. One way to implement task sequences in DRE systems is to use component middleware (Heineman & Councill 2001), which automates remoting, lifecycle management, system resource management, and deployment and configuration. In large DRE systems, the sheer number of available components often poses a combinatorial planning problem for identifying component sequences to achieve specified goals. Moreover, the dynamic nature of these systems requires runtime management and modification of deployed components.To support such DRE systems, we have developed a novel computationally efficient algorithm called the Spreading Activation Partial Order Planner (SA-POP) for dynamic (re)planning under uncertainty. Prior research (Srivastava & Kambhampati 1999) identified scaling limitations in earlier AI approaches that combine planning and resource allocation/scheduling in one computational algorithm. To address this problem, we combined SA-POP with a Resource Allocation and Control Engine (RACE), which is a reusable component middleware framework that separates resource allocation and control algorithms from the underlying middleware deployment, configuration, and control mechanisms to enforce quality of service (QoS) requirements (see http://www.dre.vanderbilt.edu/˜schmidt/WCCD.pdf for an overview of RACE). The separation of concerns between
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