K.J. Thurber

Bio: K.J. Thurber is an academic researcher. The author has contributed to research in topics: Video quality & Local area network. The author has an hindex of 3, co-authored 9 publications receiving 131 citations.

Adaptive streaming of MPEG video over IP networks

Abstract: The authors present the design of an adaptive service for streaming MPEG video over a best-effort IP network environment. The adaptive video streaming service exploits the inherent adaptiveness of video applications to perform controlled and graceful adjustments to the perceptual quality of the displayed MPEG video stream in response to fluctuations in the QoS delivered by the three primary components in the end-to-end path of a video stream, i.e., the video server, the network, and the receiver. The design supports multiple video adaptation techniques that can be applied individually or in combination to adapt the transmitted video stream in response to fluctuations in the QoS provided by the underlying system. A novel aspect of the design is a video adaptation algorithm that selects the adaptation delivering the best perceptual quality for the video playback for a given QoS delivered by the underlying infrastructure. They describe a prototype implementation of the adaptive video streaming service and present the results of a performance evaluation of this prototype system.

Source-initiated adaptive routing algorithm (SARA) for autonomous wireless local area networks

Abstract: Conventional routing protocols used in wireline and wireless networks are not designed to operate in an autonomous (or ad hoc) wireless local area network (AWLAN) environment with asymmetric (i.e. unidirectional) links. This paper presents the design of a routing protocol called source-initiated adaptive routing algorithm (SARA), for AWLAN environments that may contain asymmetric links. To allow efficient operation in a symmetric network while ensuring correct operation in asymmetric networks, SARA supports two different modes of protocol operation: one optimized for symmetric networks and the other providing additional capabilities needed for operation in asymmetric networks at a higher cost. The ability of SARA to adapt its mode of operation and optimize its execution for each network environment is one of its major advantages and distinguishes it from existing routing protocols for, wireless networks. Furthermore, within each of its operating modes, SARA supports best-effort as well as policy-based routing.

Traffic control mechanism to support video multicast over IP networks

Abstract: A major impediment to the development of networked video applications is the lack of adequate support for video multicast within the Internet Protocol (IP). This paper presents an approach for extending the capability of IP to support multicast of video streams in a heterogeneous networking environment where there are static variations in the capacities of the links and the video quality needs of the receivers as well as dynamic variations in the available bandwidth of the network links. The approach, called IP extensions for video multicast (IPEVM), uses an innovative traffic control mechanism within the network routers that dynamically adapts the quality of the video to changes in the available network bandwidth while ensuring fair treatment of all traffic contending for the network's best effort service. It also permits an application-selectable mix of resource reservation and adaptive bandwidth management to be used in building networked video applications.

Modeling ATR applications for intelligent execution upon a heterogeneous computing platform

Abstract: The information processing tasks associated with real-time applications (e.g., automatic target recognition, intelligent robotics, information fusion) have very diverse computational requirements that result in different needs for different computing system capabilities. Heterogeneous parallel computing provides a variety of architectural capabilities, orchestrated to perform an application whose tasks have such diverse execution requirements. A key issue that must be addressed in embedding real-time applications on heterogeneous parallel computing architectures is the design of a high-level operating system for selecting algorithms, matching subtasks to processors, and scheduling subtask execution. Essentially, high-level descriptions of an application would be "intelligently executed" by such an operating system. This paper presents on-going research in the development of an Intelligent Operating System, specifically describing the mechanism for the selection of algorithms that functionally satisfy the processing needs of ATR subtasks. The methodology presented here can also be used for other application domains and classes of hardware platforms whose characteristics are similar to those of the applications and platform considered here.

A framework for automated software partitioning and mapping for distributed multiprocessors

Abstract: One of the major impediments to the widespread use of large-scale, distributed memory multiprocessors is the difficulty of efficiently partitioning and mapping application algorithms onto these machines so as to extract a large portion of the machines' peak performance. In this paper, we present the preliminary accomplishments of an ongoing effort aimed at automating the complex tasks of software partitioning and mapping during the: system definition phase of application development for distributed memory multiprocessors. We describe a technique called the Augmented Task Dependency Graph (ATDG) for representing the high-level design of the application software. The ATDG allows one to express functional parallelism as well as data parallelism in a manner that facilitates automated partitioning and mapping. We propose a new strategy for searching through the possible space of design choices for partitioning and mapping. The proposed approach, called hierarchical hybrid search, organizes the search space as a hierarchy of sub-spaces. It permits the use of different search techniques for searching through different search sub-spaces. Examples of search techniques that could be employed in the proposed approach include hill-climbing, simulated annealing, and genetic algorithms.

Real-time or near real-time streaming

Abstract: Methods and apparatuses provide real-time or near real-time streaming of content, specified in one or more playlists, using transfer protocols such as an HTTP compliant protocol. In one embodiment, a method can execute a user application on a client device to present media files and to control presentation of the media files. The method can further run a media serving process on the client device to retrieve a playlist specifying the media files and a media source at which the media files are available, to retrieve the media files from the media source, and to decode the media files retrieved. The media serving process can call the user application to process a custom URL in order to obtain an object referred to by the custom URL.

Playlists for real-time or near real-time streaming

Abstract: Methods and apparatuses for real-time or near real-time streaming of content using transfer protocols such as an HTTP compliant protocol. In one embodiment, a method includes dividing a stream of data, representing the contiguous time based content of a program (e.g. a live video broadcast), into a plurality of distinct media files, and generating a playlist file having a plurality of tags and Universal Resource Indicators (URIs) indicating an order of presentation of the plurality of distinct media files. The plurality of media files and the playlist file can be made available for transmission to a client device which can retrieve the media files using the playlist file.

Real-world experiences with an interactive ad hoc sensor network

Abstract: While it is often suggested that moderate-scale ad hoc sensor networks are a promising approach to solving real-world problems, most evaluations of sensor network protocols have focused on simulation, rather than realworld, experiments. In addition, most experimental results have been obtained in limited scale. This paper describes a practical application of moderate-scale ad hoc sensor networks. We explore several techniques for reducing packet loss, including quality-based routing and passive acknowledgment, and present an empirical evaluation of the effect of these techniques on packet loss and data freshness.

System for providing data to multiple devices and method thereof

Abstract: A system is provided for transmitting data to a plurality of devices. A data source receives data from a video broadcasting source, such as a digital television provides, through a data cable. The data source identifies devices to receive particular sets of data, such as particular programs, from the data cable. The data source identifies particular settings for transmitting to particular devices. The data source adjusts a transmission power to a first device to efficiently provide data reliably to the first device. The data source can assign more or less power for transmitting data to the first device. The data source provides data to the source device using a first data channel. The data source provides data to a second device using a second data channel. The data source receives acknowledgements and control information from the first device and the second device using the second data channel.

Adaptive streaming of MPEG video over IP networks

Abstract: The authors present the design of an adaptive service for streaming MPEG video over a best-effort IP network environment. The adaptive video streaming service exploits the inherent adaptiveness of video applications to perform controlled and graceful adjustments to the perceptual quality of the displayed MPEG video stream in response to fluctuations in the QoS delivered by the three primary components in the end-to-end path of a video stream, i.e., the video server, the network, and the receiver. The design supports multiple video adaptation techniques that can be applied individually or in combination to adapt the transmitted video stream in response to fluctuations in the QoS provided by the underlying system. A novel aspect of the design is a video adaptation algorithm that selects the adaptation delivering the best perceptual quality for the video playback for a given QoS delivered by the underlying infrastructure. They describe a prototype implementation of the adaptive video streaming service and present the results of a performance evaluation of this prototype system.