Feature interactions occur when one feature interferes with the intended operation of another feature. To detect such interactions, each new feature must be tested against existing features. The detected interactions must then be resolved; many existing approaches to resolving interactions require the feature set be prioritized. Unfortunately, the cost to determine a priority ordering for a feature set increases dramatically as the number of features increases. This thesis explores strategies to decrease the cost of prioritizing features, and thus facilitates priority-based solutions to resolving feature interactions. Specifically, this thesis introduces a categorization approach that reduces the complexity of determining priorities for a large set of features by decomposing the prioritization problem. Our categorization approach reduces this cost by using abstraction to divide the system's features into categories based on their main goal or functionality (e.g., block unwanted calls, present call information). Next, in order to detect and resolve the interactions that occur between these seemingly unrelated categories, we identify a set of principles for proper system behaviour that define acceptable behaviour in the global system. For example, a call that should be blocked by a call-screening feature should never result in a voice connection. The categories are then ordered, such that adherence to the principles is optimized. We show that using category priorities, to order a large feature set, correctly resolves interactions between individual features and significantly reduces the cost to determine priority orderings. The four significant contributions that this thesis makes are: 1) the categorization of features, 2) the principles of proper system behaviour, 3) automatic generation of priority orderings for categories, and 4) devising several optimizations that reduce the search space when exploring call simulations during the automatic generation of the priority orderings. These contributions are examined with respect to the telephony domain and result in the identification of 12 feature categories and 9 principles of proper system behaviour. A Prolog model was also created to run call simulations on the categories, using the identified principles as correctness criteria. Our case studies showed the reduced cost of our categorization approach is approximately 1/10^(55) % of the cost of a traditional approach. Given this significant reduction in the cost and the ability of our model to accurately reproduce the manually identified priority orderings, we can confidently argue that our categorization approach was successful. The three main limitations of our categorization approach are: 1) not all features (e.g., 911 features in telephony) can be categorized or some categories will contain a small number of features, 2) the generated priority ordering may still need to be analyzed by a human expert, and 3) the run time for our automatic generation of priority orderings remains factorial with respect to the size of the number of categories. However, these limitations are small in comparison to the savings generated by the categorization approach.

Interactive multimedia sessions combine requirements of traditional telephony services and Internet applications. This requires call setup, call signaling, negotiation, routing, security, and network resources. Seeking to facilitate the use of quality of service (QoS) mechanisms to users of such applications, this thesis presented new signaling architectures that addressed the interaction of the Session Initiation Protocol (SIP) as the session control signaling protocol and current resource management frameworks. The Differentiated Services (DiffServ) architecture is used as the primary example. The new architectures addressed the roles of SIP agents and proxy servers in subjects such as resource negotiation, call authorization, and end-to-end QoS in heterogeneous networks. First, an architecture based on the use of QoS-enhanced SIP proxies and a SIP-based interface between the application and network layers was developed, implemented in a testbed, and performance enhancements demonstrated. Further studying of the Internet Engineering Task Force (IETF) proposal for the integration of SIP and resource management led to the development of a new signaling scheme, Resource management Overlapped with Answering Delay (ROAD). It explores the SIP user agent interaction with the network in a way that takes advantage of parallel user answering delays and reservation delays. An experimental evaluation of the ROAD scheme showed its call setup delay savings and reduced signaling load. Then, on the interaction of SIP and call admission control, an inter-domain call authorization model that implements the concepts of proxies as gate controllers (QoS-enhanced SIP proxies-GC), and that provides call authorization status and adds more granularity to the authorization process is proposed. This model showed to be scalable in terms of the need to add more resources to compensate for the increasing service load on the servers. Finally, an example framework that applies the new signaling architectures to achieve end-to-end QoS in heterogeneous networks is presented.

Thesis (M.S.)--University of Florida, 2002. / Title from title page of source document. Includes vita. Includes bibliographical references.

<p>Communication tools such as text-based instant messaging, voice and video relay services, real-time video chat and mobile SMS and MMS have successfully been used among Deaf people. Several years of field research with a local Deaf community revealed that disadvantaged South African Deaf&nbsp / people preferred to communicate with both Deaf and hearing peers in South African Sign Language as opposed to text. Synchronous video chat and video&nbsp / relay services provided such opportunities. Both types of services are commonly available in developed regions, but not in developing countries like South&nbsp / Africa. This thesis reports on a workaround approach to design and develop an asynchronous video communication tool that adapted synchronous video&nbsp / &nbsp / codecs to store-and-forward video delivery. This novel asynchronous video tool provided high quality South African Sign Language video chat at the&nbsp / expense of some additional latency. Synchronous video codec adaptation consisted of comparing codecs, and choosing one to optimise in order to&nbsp / minimise latency and preserve video quality. Traditional quality of service metrics only addressed real-time video quality and related services. There was no&nbsp / uch standard for asynchronous video communication. Therefore, we also enhanced traditional objective video quality metrics with subjective&nbsp / assessment metrics conducted with the local Deaf community.</p>

No description available.

<p>This thesis explored how hearing and deaf users are brought together into one communication space where interaction between them is a semi-synchronous form of message exchange. The focus of this thesis was the means by which message delivery between two e</p>

Thesis (Ph. D.)--University of Nevada, Reno, 2007. / "May, 2007." Includes bibliographical references (leaves 85-104). Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2007]. 1 microfilm reel ; 35 mm.

Thesis (M.App.Sc.) - Carleton University, 2002. / Includes bibliographical references (p. 157-161). Also available in electronic format on the Internet.

Thesis (M.Sc.) - Carleton University, 2003. / Includes bibliographical references (p. 148-151). Also available in electronic format on the Internet.

Thesis (M.S. in Information Technology Management)--Naval Postgraduate School, March 2005. / Thesis Advisor(s): Dan C. Boger, R. Scott Coté. Includes bibliographical references (p. 134-138). Also available online.