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Full-Text Articles in Engineering
Thread Transparency In Information Flow Middleware, Rainer Koster, Andrew P. Black, Jie Huang, Jonathan Walpole, Calton Pu
Thread Transparency In Information Flow Middleware, Rainer Koster, Andrew P. Black, Jie Huang, Jonathan Walpole, Calton Pu
Computer Science Faculty Publications and Presentations
Existing middleware is based on control-flow centric interaction models such as remote method invocations, poorly matching the structure of applications that process continuous information flows. Difficulties cultiesin building this kind of application on conventional platforms include flow-specific concurrency and timing requirements, necessitating explicit management of threads, synchronization, and timing by the application programmer. We propose Infopipes as a high-level abstraction for information flows, and we are developing a middleware framework that supports this abstraction. Infopipes transparently handle complexities associated with control flow and multi-threading. From high-level configuration descriptions the platform determines what parts of a pipeline require separate threads or …
Quality Of Service Semantics For Multimedia Database Systems, Jonathan Walpole, Charles Krasic, Ling Liu, David Maier, Calton Pu, Dylan Mcnamee, David Steere
Quality Of Service Semantics For Multimedia Database Systems, Jonathan Walpole, Charles Krasic, Ling Liu, David Maier, Calton Pu, Dylan Mcnamee, David Steere
Computer Science Faculty Publications and Presentations
Quality of service (QoS) support has been a hot research topic in multimedia databases, and multimedia systems in general, for the past several years. However, there remains little consensus on how QoS support should be provided. At the resource-management level, systems designers are still debating the suitability of reservation- based versus adaptive QoS management. The design of higher system layers is less clearly understood, and the specification of QoS requirements in domain-specific terms is still an open research topic. To address these issues, we propose a QoS model for multimedia databases. The model covers the specification of user-level QoS preferences …
A Player For Adaptive Mpeg Video Streaming Over The Internet, Jonathan Walpole, Rainer Koster, Shanwei Cen, Crispin Cowan, David Maier, Dylan Mcnamee, Calton Pu, David Steere, Liujin Yu
A Player For Adaptive Mpeg Video Streaming Over The Internet, Jonathan Walpole, Rainer Koster, Shanwei Cen, Crispin Cowan, David Maier, Dylan Mcnamee, Calton Pu, David Steere, Liujin Yu
Computer Science Faculty Publications and Presentations
This paper describes the design and implementation of a real-time, streaming, Internet video and audio player. The player has a number of advanced features including dynamic adaptation to changes in available bandwidth, latency and latency variation; a multi-dimensional media scaling capability driven by user-specified quality of service (QoS) requirements; and support for complex content comprising multiple synchronized video and audio streams. The player was developed as part of the QUASAR t project at Oregon Graduate Institute, is freely available, and serves as a testbed for research in adaptive resource management and QoS control.
Script-Based Qos Specifications For Multimedia Presentations, Richard Staehli, Jonathan Walpole
Script-Based Qos Specifications For Multimedia Presentations, Richard Staehli, Jonathan Walpole
Computer Science Faculty Publications and Presentations
Multimedia presentations can convey information not only by the sequence of events but by their timing. The correctness of such presentations thus depends on the timing of events as well as their sequence and content. This paper introduces a formal specification language for playback of real-time presentations. The main contribution of this language is a quality of service (QOS) specification that relaxes resolution and synchronization requirements for playback. Our definitions give a precise meaning to the correctness of a presentation. This specification language will form the basis for a QOS interface for reservation of operating system resources.