Thesis (Ph.D.)--University of Texas at Dallas, 2008. / Includes vita. Includes bibliographical references.

Thesis (Ph. D.)--Computing, Georgia Institute of Technology, 2006. / Schwan, Karsten, Committee Chair ; Ramachandran, Kishore, Committee Member ; Ahamad, Mustaque, Committee Member ; Yalamanchili, Sudhakar, Committee Member ; Howe, W. Gerry, Committee Member. Vita. Includes bibliographical references.

Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.

Thesis (M.S.)--University of Texas at Dallas, 2008. / Includes vita. Includes bibliographical references (leaves 57-61)

Advances in computer technology such as faster processors, better data compression schemes, and cheaper audio and video devices have made it possible to integrate multimedia into the computing environment. Desktop conferencing evolved as a plausible result of this multimedia revolution. The bandwidth granted for these conferencing applications is restricted in most cases by the speed of the modem device connected to the network. Poor performance of multimedia conferencing over the Internet can be attributed to two main factors: local and remote induced effects. Local effects are induced by bandwidth sharing between different media components, operating system limitations, or poor design. Remote effects include all Internet related problems such as unfairness, nonguaranteed quality of service, congestion, etc. Both effects are addressed in this study and some solutions are proposed. The primary goal is to maintain audio quality and prevent video from degrading audio performance. We study characteristics of video and audio traffic sources of conferencing applications following the H.323 set of standards defined by the International Telecommunication Union (ITU). The media traffic uses the Real-time Transport Protocol (RTP) and User Datagram Protocol (UDP) as their transport vehicle over IP network protocol. Tradeoffs involved in the choice of multimedia traffic parameters are presented. Our measurements were carried out on audio and video codecs defined in G.723.1 and H.263 specifications respectively, both drafted by the ITU. This dissertation investigates traffic multiplexing issues at the host, and the interaction of conferencing media components as they are multiplexed locally in a shared bandwidth transport medium. Lack of appropriate multiplexing algorithms can lead to one or more media components oversubscribing to the shared bandwidth and penalizing other participants. These local effects can contribute significantly to traffic delay or abuse of the network bandwidth. We propose the “bit rate adjuster” (BRA) algorithm and use it the network bandwidth. We propose the “bit rate adjuster” (BRA) algorithm and use it for regulating media flow. The algorithm compensates for video local effects induced by packet preparation or processing to allow for better audio performance. A new performance qualifier is introduced and used in the evaluation process. Further on the remote side, we investigate reactive mechanisms used to recover media flow performance degradation caused by shared bandwidth traffic effects. We overview feedback mechanisms based on the Real-time Control Protocol (RTCP). We uncover its limitation on applications connected to the Internet through narrow bandwidth pipes. We propose an alternative approach that predicts and prevents the loss of audio packets before it occurs based on local computation of audio jitter. We also propose a mechanism that recovers audio traffic from jitter and latency effects introduced by the Internet shared medium. These approaches improve the audio performance significantly in multimedia conferencing sessions. / Graduate

In order to avoid repeating the patterns of past failed technology initiatives, eschew various types of paralyzing blame cultures, capitalize on the momentum offered by outside stakeholder interest, and maintain the agency to stay consistent with our own techno-theories and pedagogies, this study develops a model writing program administrators (WPAs) can utilize in order to create sustainable programmatic technology inclusion (SPTI) in their First Year Composition (FYC) programs. In order to achieve this, this study uses a national survey of FYC stakeholders and interviews and focus groups with FYC directors, instructors, and students at three different institutional types to explore the comprehensiveness and usefulness of Dickie Selfe's framework of a three-step process and three additional complications from Sustainable Computer Environments. The findings from this research are then paired with Kristie Fleckenstein et al.'s "ecology of mind" from "A Portable Ecology" to create a sustainability-focused constellation of interrelated and interdependent ecologies that can serve as a model for WPAs to embed in their own institutional contexts and employ in their FYC programs. / A Dissertation submitted to the Department of English in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester, 2014. / August 11, 2014. / Technology-inclusion, Writing Program Administration / Includes bibliographical references. / Michael Neal, Professor Directing Dissertation; Sherry Southerland, University Representative; Kathleen Blake Yancey, Committee Member; Leigh Edwards, Committee Member.

In July 2013, the social media Facebook campaign, Save the Miami-Dade Public Libraries (SMDPL) sought to influence the Miami-Dade County Mayor and Board of County Commissioners to reverse proposed budget cuts and maintain existing library funding levels. In this study, I examined the SMDPL campaign by conducting a discourse analysis of Facebook discussions that included posts, comments and any artifacts referenced such as other websites, mainstream media, public official memoranda and public documents, among others. I examined the expressions of value and the policymaking process using Moore's Creating Public Value Theory. This study found that Creating Public Value offered an examination of public institutions as subsets of public sector governance. The study found that discourse is an element of the public value created that resulted in expression of public value outcomes and operational capacity for communities. However the study also found that public library advocates missed opportunities to demonstrate rather than assert, specific public library values. Information sharing using social network sites can be important sources of what a community values in their libraries and their public sector institutions. Future research could examine how these values influence the actions of public officials and the discourse can become a source of examining what all types of communities' value in libraries. / A Dissertation submitted to the School of Information in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Spring Semester 2016. / April 4, 2016. / advocacy, discourse analysis, Facebook, public libraries, public policy, social network sites / Includes bibliographical references. / Lorraine Mon, Professor Directing Dissertation; Stephen McDowell, University Representative; Charles R. McClure, Committee Member; Marcia A. Mardis, Committee Member.

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