15030600
Support for Distributed Pair Programming in the Transparent Video Facetop
The Transparent Video Facetop is a novel user interface concept that supports not only single-user interactions with a PC, but also close pair collaborations, such as that found in collaborative Web browsing, remote medicine, and in distributed pair programming. In this paper we discuss the use of a novel video-based UI called the Facetop [16] for solving several problems reported to us by teams doing distributed pair programming. Specifically, the Facetop allows a distributed pair to recapture some the facial expressions and face-to-face communications contact lost in earlier distributed sessions. It also allows members of a distributed pair to point conveniently, quickly, and naturally to their shared work, in the same manner (manually) that they do when seated side-by-side. Our results enhance the ability of organizations to do effective XP-style agile development with distributed teams.
2547072
An orthogonal taxonomy for hyperlink anchor generation in video streams using OvalTine
As dynamically linked content follows the progression of statically linked media into the realm of video, new opportunities for link creation become apparent. In this paper we describe a real-time video hypermedia system with user-definable linkage areas, in a distributed collaborative environment. We also investigate the extension of such a system to automated link creation in video streams. In the process, we identify and describe orthogonal issues of hypervideo anchor creation. An example system, OvalTine, has been produced to illustrate several potential uses through configuration of an extended video conferencing application on the SGI O2 platform.
17495706
Fault-tolerance in distributed query processing
Fault-tolerance has long been a feature of database systems, with transactions supporting the structuring of applications so as to ensure continuation of updating applications in spite of machine failures. For read-only queries the perceived wisdom has been that support for fault-tolerance is too expensive to be worthwhile. Distributed query processing is coming to be seen as a promising way of implementing applications that combine structured data and analysis operations in dynamic distributed settings such as computational grids. Such a query may be long-running and having to redo the whole query after a failure may cause problems (e.g. if the result may trigger business or safety critical activities). This work describes and evaluates a new scheme for adding fault-tolerance to distributed query processing through a rollback-recovery mechanism. The high level expression of user requests in a physical algebra offers opportunities for tuning the fault-tolerance provision so as to reduce the cost, and give better performance than employment of generic fault-tolerance mechanisms at the lowest level of query processing. This paper outlines how the publicly-available OGSA-DQP computational grid-based distributed query processing system can be modified to include support for fault-tolerance and presents a performance evaluation which includes measurements of the cost of both protocol overheads and rollback-recovery, for a set of example distributed queries.
1442195
Modeling superscalar processors via statistical simulation
Statistical simulation is a technique for fast performance evaluation of superscalar processors. First, intrinsic statistical information is collected from a single detailed simulation of a program. This information is then used to generate a synthetic instruction trace that is fed to a simple processor model, along with cache and branch prediction statistics. Because of the probabilistic nature of the simulation, it quickly converges to a performance rate. The simplicity and simulation speed make it useful for fast design space exploration; as such, it is a good complement to conventional detailed simulation. The accuracy of this technique is evaluated for different levels of modeling complexity. Both errors and convergence properties are studied in detail. A simple instruction model yields an average error of 8% compared with detailed simulation. A more detailed instruction model reduces the error to 5% but requires about three times as long to converge.
84054
Adapting Multimedia Internet Content for Universal Access
Content delivery over the Internet needs to address both the multimedia nature of the content and the capabilities of the diverse client platforms the content is being delivered to. We present a system that adapts multimedia Web documents to optimally match the capabilities of the client device requesting it. This system has two key components. 1) A representation scheme called the InfoPyramid that provides a multimodal, multiresolution representation hierarchy for multimedia. 2) A customizer that selects the best content representation to meet the client capabilities while delivering the most value. We model the selection process as a resource allocation problem in a generalized rate distortion framework. In this framework, we address the issue of both multiple media types in a Web document and multiple resource types at the client. We extend this framework to allow prioritization on the content items in a Web document. We illustrate our content adaptation technique with a web server that adapts multimedia news stories to clients as diverse as workstations, PDA's and cellular phones.
7544123
Models and Heuristics for Robust Resource Allocation in Parallel and Distributed Computing Systems
This is an overview of the robust resource allocation research efforts that have been and continue to be conducted by the CSU robustness in computer systems group. Parallel and distributed computing systems, consisting of a (usually heterogeneous) set of machines and networks, frequently operate in environments where delivered performance degrades due to unpredictable circumstances. Such unpredictability can be the result of sudden machine failures, increases in system load, or errors caused by inaccurate initial estimation. The research into developing models and heuristics for parallel and distributed computing systems that create robust resource allocations is presented.
32704360
Interactive content-based retrieval of video
We describe a system for content-based retrieval of video that involves a series of query interactions with the user. The proposed approach allows the user, iteratively and selectively, to integrate different feature- and model-based methods of querying in the search process. This allows the user to choose among different retrieved content, features and matching dimensions, and classifiers, as appropriate, given the query objective and interim retrieval results. We investigate several approaches for integrating featureand model-based queries and results in successive query rounds including iterative filtering, score aggregation, and relevance feedback searching. We describe experimental results of applying the interactive content-based retrieval method to an automatically indexed corpus of 11 hours of video.