Steve Ward

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Contemporary pervasive computing environments demand mechanism for coherently addressing high-level user needs despite changing availability of resources. We propose the formalization of goals as the semantic basis for this mechanism, and sketch a system architecture that separates policy-rich goals-level planning code from a policy-neutral component(More)
The NuMesh system defines a high-speed communication sub-strate optimized for off-line routing. By determining possible communication paths at compile time, highly efficient hardware and software constructs can be exploited to yield superior network performance. These communication paths can be independently tuned to allow more utilized paths greater(More)
Cloud systems differ fundamentally in how they offer and charge for resources. While some systems provide a generic programming abstraction at coarse granularity, e.g., a virtual machine rented by the hour, others offer specialized abstractions with fine-grained accounting on a per-request basis. In this paper, we explore Tasklets, an abstraction for(More)
The structural similarity index (SSIM) has been shown to be a superior objective image quality metric. A web-based pilot experiment was conducted with the goal of quantifying, through the use of a sample of human participants, a trend in SSIM values showing when the human visual system can begin to perceive distortions applied to reference images. The just(More)
We describe an approach to automate certain high- level implementation decisions in a pervasive application, allowing them to be postponed until run time. Our system enables a model in which an application programmer can specify the behavior of an adaptive application as a set of open-ended decision points. We formalize decision points as goals, each of(More)
Many standardized hardware communication interfaces offer run-time flexibility and configurability at the cost of efficiency. An alternate approach is the use of a highly-efficient, minimal communication element, with as much communication decision-making as possible done at compile time. NuMesh is a packaging and interconnect technology supporting(More)
We present ChunkStream, a system for efficient streaming and interactive editing of online video. Rather than using a specialized protocol and stream format, ChunkStream makes use of a generic mechanism employing chunks. Chunks are fixed-size arrays that contain a mixture of scalar data and references to other chunks. Chunks allow programmers to expose(More)
We present a middleware platform for assembling pervasive applications that demand fault-tolerance and adaptivity in distributed, dynamic environments. Unlike typical adaptive middleware approaches, in which sophisticated component model semantics are embedded into an existing, underlying platform (e.g., CORBA, COM, EJB), we propose a platform that imposes(More)