Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 122-124). Also available in electronic version. Access restricted to campus users.

Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xvi, 188 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: Jean-Michel Guldmann, Dept. of City and Regional Planning. Includes bibliographical references (p. 164-170).

Thesis (M.S.)--University of Florida, 2002. / Title from title page of source document. Document formatted into pages; contains viii, 100 p.; also contains graphics. Includes vita. Includes bibliographical references.

Thesis (M. Sp. Path. St.)--University of Queensland, 2002. / Includes bibliographical references.

Thesis (M.S. in Computer Science)--Naval Postgraduate School, March 2003. / Thesis advisor(s): Shing Man-Tak, Joseph Pruett, Richard Riehle. Includes bibliographical references (p. 249-252). Also available online.

Thesis (M. Sc. (Physics))--Rhodes University, 2003.

This study examines the activity of an online community in developing design creativity. This involved undergraduate Malaysian university students and their tutor from the School of Education, and professional designers in a private online community using the social network site - Facebook - to improve interface design (websites or interactive courseware). Two research processes adapted from different communities - the creative industries and the higher education communities - were applied in the collaboration. Each community embraces distinctive methods, objectives, instruments, rules and roles in producing design. Contradictions and tensions resulting from incorporating these two communities were analysed. In addition, the effect of social interactions on students’ performance, awareness, and perspectives were also investigated. A qualitative approach was utilized and data consisted of online semi-structured questionnaires, face-to-face interviews, field documentation on Facebook, and Facebook chat. The process of analysis is divided into two parts: initial analysis and substantive analysis of four case studies. Thematic (Braun and Clarke, 2006) and comprehensive data treatment (Silverman, 2010) approaches were used to analyse the initial data. Activity systems analysis (Engeström, 1999) was employed in the substantive analysis to explore the contradictions within the collaboration. The results indicate that contradictions occurred due to the new practice introduced by the community of practitioners (the designers). The collision of new practice positioned students in a disequilibrium stage but managed to also improve students’ design outcomes and promote awareness of the importance of producing purposeful design. However it also revealed the importance of both cognitive and emotional support during the process as the harsh nature of the feedback from designers could potentially hinder creativity. The findings of this study contribute to our understanding that the social-cultural process of creativity can be nurtured within higher education through the use of social network sites such as Facebook. It concludes that more research exploring online social interactions between a learning community and a community of practitioners is required in order to better understand the benefits it has to offer for creativity development.

published_or_final_version / Public Health / Master / Master of Public Health

published_or_final_version / Public Health / Master / Master of Public Health

The Internet is dynamically shared by numerous flows of data traffic. Network congestion occurs when the aggregate flow rate persistently exceeds the network capacity, leading to excessive delivery delay and loss of user data. To control network congestion, a flow needs to adapt the sending rate to its inferred level of congestion, and a packet switch needs to report its local level of congestion. In this framework of Internet congestion control, it is important for flows to react promptly against congestion, and robustly against interfering network events resembling congestion. This is challenging due to the highly dynamic interactions of various network components over a global scale. Prior approaches rely predominantly on empirical observations in experiments for constructing and validating designs. However, without a careful, systematic examination of all viable options, more efficient designs may be overlooked. Moreover, experimental results have limited applicability to scenarios beyond the specific experimental settings. In this thesis, I employ a novel, systematic design approach. I formalize the design process of Internet congestion control from a minimal set of empirical observations. I prove the robustness and optimality of the attained design in general settings, and validate these properties in practical experimental settings. First, I develop a systematic method for enhancing the robustness of flows against interfering events resembling congestion. The class of additive-increase-multiplicative-decrease (AIMD) algorithms in Transmission Control Protocol (TCP) is the set of dominant algorithms governing the flow rate adaptation process. Over the present Internet, packet reordering and non-congestive loss occur frequently and are misinterpreted by TCP AIMD as packet loss due to congestion. This leads to underutilization of network resources. With a complete, formal characterization of the design space of TCP AIMD, I formulate designing wireless TCP AIMD as an optimal control problem over this space. The derived optimal algorithm attains a significant performance improvement over existing enhancements in packet-level simulation. Second, I propose a novel design principle, known as pricing-link-by-time (PLT), that specifies how to set the measure of congestion, or “link price”, at a router to provide prompt feedback to flows. Existing feedback mechanisms require sophisticated parameter tuning, and experience drastic performance degradation with improperly tuned parameters. PLT makes parameter tuning a simple, optional process. It increases the link price as the backlog stays above a threshold value, and resets the price once the backlog goes below the threshold. I prove that such a system exhibits cyclic behavior that is robust against changes in network environment and protocol parameters. Moreover, changing the threshold value can control delay without undermining system performance. I validate these analytical results using packet-level simulation. The incremental deployment of various enhancements have made Internet congestion control highly heterogeneous. The final part of the thesis studies this issue by analyzing the competition among flows with heterogeneous robustness against interfering network events. While rigorous theories have been a major vehicle for understanding system designs, the thesis involves them directly in the design process. This systematic design approach can fully exploit the structural characteristics, and lead to generally applicable, effective solutions. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy