Magister Scientiae - MSc (Computer Science) / This thesis describes the development cycles of an authoring tool that generalises scenario creation for SignSupport. SignSupport is a mobile communication tool for Deaf people that currently runs on an Android smartphone. The authoring tool is computer-based software that helps a domain expert, with little or no programming skills, design and populate a limited domain conversation scenario between a Deaf person and a hearing person, e.g., when a Deaf patient collects medication at a hospital pharmacy or when a Deaf learner is taking a computer literacy course. SignSupport provides instructions to the Deaf person in signed language videos on a mobile device. The authoring tool enables the creation and population of such scenarios on a computer for subsequent 'playback' on a mobile device. The output of this authoring tool is an XML script, alongside a repository of media les that can be used to render the SignSupport mobile app on any platform. Our concern was to iteratively develop the user interface for the authoring tool, focusing on the domain experts who create the overall flow and content for a given scenario. We had four development iterations, where the rst three were evaluated for usability; for both pharmacy and ICDL course scenarios with purposive sampling. The fourth iteration focused on using the authoring tool to design an ICDL practise mobile app, recording the necessary SASL videos and using an XML parser to render the designs XML script into an Android app. The research conducted herein leveraged multiple approaches to content authoring and generalisation; and further that software generalisation can improve accessibility and a ordability for the ultimate end users. The thesis concludes with a summary of recommendations and lessons learnt.

This thesis proposes a multistage RAKE receiver for use at the base station of a Code Division Multiple Access (CDMA) cellular communications system. This receiver combines the interference rejection capability of multiuser receivers with the robust performance of a RAKE receiver in the presence of multipath interference. Unlike previous multiuser receiver designs, this multistage RAKE receiver requires no a priori information about the time-vary multipath radio channel. The thesis presents a mathematical description of the multistage receiver, and a software simulation of the receiver performance. A wide range of channel models are considered which include the effects of Gaussian noise, multipath propagation, imperfect power control and multiple access interference for the reverse link CDMA channel. Under a wide range of conditions, the multistage RAKE receiver is able to support two to three times as many users as a conventional single stage RAKE receiver. The receiver is also shown to be robust to the near-far problem. / Master of Science

The design of cellular wireless communication systems is influenced by the propagation characteristics of the channel and their effect on transmitted signals. The multipath propagation characteristics of a channel, except under simple transmission conditions, limits the design of emerging cellular systems. Once the propagation conditions are understood, systems can be designed more efficiently in terms of site layout and frequency planning, to reduce deployment costs and improve performance. A software tool for site specific radio propagation prediction is being developed at the Mobile and Portable Radio Group, Virginia Tech. The objective of this research is to develop re-usable program modules that can be utilized to implement several functional features of the software. This thesis describes the raster and vector programming libraries that have been developed during this research. These libraries are utilized in the database module, user interface and graphics module and propagation prediction module of the software. Significant among the capabilities that these libraries provide are the ability to store and retrieve raster and vector data from the database, import measured and predicted data available in standard data formats into the database, obtain user inputs through an interactive mechanism, display images of site specific information at various resolutions, and enable the user to view and analyze measured and predicted data. This thesis also presents the data format, that has been defined during this research, to acquire and import contour and elevation information of buildings. The SISP General Data Format (GDF), that has been developed, to facilitate import of measured and predicted data has also been described. The Hierarchical Data Format (HDF), developed by the National Center for Supercomputing Applications (NCSA), has been adopted to store measured and predicted data in the database. The programming techniques used to retrieve and display data stored in this format are also outlined in this thesis. SISP has been developed on Sun Sparc workstations. Details of the function libraries that have been developed, programming methodologies employed, and data formats that have been defined for site specific and measured and predicted RF data are included in this thesis. / Master of Science

The objective of this research is to compare radio channel impulse response measurements with site-specific radio wave propagation prediction techniques. A wide band spread spectrum measurement system was developed, and desirable measurement locations were selected on the Virginia Tech campus. These measurements are designed togo beyond statistical characterizations of the channel and will aid in determining how the propagation environment is influencing the multi path propagation. The objective is to not only measure the delays and relative powers of multi path components, but to carefully document their angles of arrival and resolve the overall paths that these multipaths had to take to reach the receiver. This information will be used to compare with propagation prediction simulations using the modeled environment, and therefore, provide new insight into the nature of reflection and scattering of radio propagation in typical microcellular environments. As a first step in this endeavor, building surface characterizations are made in order to determine empirical reflection coefficients of common building materials. Propagation experiments have been designed to determine applicability of Fresnel reflection formulas to non-ideal conditions, such as waves that are not perfect plane waves, rough surfaces, etc. This information allows propagation prediction techniques to further quantify the site-specific mobile radio environment and yield more accurate propagation estimates. For this endeavor, Whittemore Hall and Squires Student Center were Chosen to provide reflection measurements from rough stone, glass, and brick surfaces. Detailed descriptions of measurement techniques, analysis and results are included. / Master of Science

University of Macau / Faculty of Social Sciences and Humanities / Department of Communication

Thesis (MPhil (Information Science))--University of Stellenbosch, 2009. / Mobile telephone subscription in developing countries has increased by more than 500 percent since 2005, with Africa experiencing the highest growth rate globally. Amongst Africa’s 306.5 million subscribers, recorded in 2008, an unexpectedly high adoption rate of the technology by poor, often illiterate rural communities is observed. Mobile telephony generally provides African rural users access to electronic communication for the first time. Providing access to communication, information and knowledge, mobile phones present a platform for economic and social interaction in rural Africa. The extent of the resulting positive socio-economic impact on the developing world has lead to mobile telephony increasingly being viewed as a potential development tool for the socio-economic upliftment of the rural poor. This thesis is inspired by the potential for value creation to end users of mobile telephony, leading to the proposition that the rapid expansion of mobile telephony in rural Africa can contribute significantly to the sustainability of these communities’ rural livelihoods. For this proposition to be valid, mobile telephony has to provide value beyond being communication tool. It has to provide value in income generating activities by increasing opportunities for access to financial and social capital with mobile business models appropriate to the rural African context. To assess the appropriateness of mobile value offerings, the rural African context was analyzed using the Sustainable Livelihoods Framework. Through multi-level analysis, the challenges and issues that influence the lives of the rural poor were explored and the dominant livelihood strategies in terms of income generating activities were identified. Apart from agricultural income streams, waged labor, migration and micro-entrepreneurial activities provide non-agricultural income streams. Creating an appropriate mobile business ecosystem for rural Africa requires the collaboration of a complex network of actors within a value constellation to co-produce value for the end users. Three conditional factors were identified for mobile telephony and emerging mobile business models to contribute successfully to sustainable livelihoods: adaptation of the technology by providers, user appropriation to make the technology their own and the assimilation of it into their livelihood strategies. These factors were researched for validation through the study of existing literature and reported case studies. It was found that these three conditional factors were unequivocally met. Firstly, the mobile telecommunication industry active in Africa is seen to successfully adapt and innovate solutions that are relevant to African rural communities’ vulnerabilities and livelihood strategies. Secondly, African mobile phone users have successfully adopted and appropriated mobile telephony to create value for themselves in their livelihood strategies, often independent of external interventions. They are claiming ownership of the technology and not merely using it as a communication tool. Thirdly, by assimilating mobile telephony into their livelihood strategies, value-creation within their income generating activities have been made possible. This value creation is impacting users’ social and financial capital positively. This thesis concludes that mobile telephony and emerging mobile business models are contributing to increasing African rural dwellers’ income generating potential, reducing their vulnerability to shocks, and providing them with a voice; thereby contributing to sustainable rural livelihoods.

High power dissipation and on-chip temperature limit performance and affect reliability in modern microprocessors. For servers and data centers, they determine the cooling cost, whereas for handheld and mobile systems, they limit the continuous usage of these systems. For mobile systems, energy consumption affects the battery life. It can not be ignored for desktop and server systems as well, as the contribution of energy continues to go up in organizations’ budgets, influencing strategic decisions, and its implications on the environment are getting appreciated. Intelligent trade-offs involving these quantities are critical to meet the performance demands of many modern applications. Dynamic Voltage and Frequency Scaling (DVFS) offers a huge potential for designing trade-offs involving energy, power, temperature and performance of computing systems. In our work, we propose and evaluate DVFS schemes that aim at minimizing energy consumption while meeting a performance constraint, for both sequential and parallel applications. We propose a Petri net based program performance model, parameterized by application properties, microarchitectural settings and system resource configuration, and use this model to find energy efficient DVFS settings. We first propose a DVFS scheme using this model for sequential programs running on single core multiple clock domain (MCD) processors, and evaluate this on a MCD processor simulator. We then extend this scheme for data parallel (Single Program Multiple Data style) applications, and then generalize it for stream applications as well, and evaluate these two schemes on a full system CMP simulator. Our experimental evaluation shows that the proposed schemes achieve significant energy savings for a small performance degradation.

In this thesis I explore the relationship between the mobile phone and its user and argue that this relationship is crucial in merging the contexts of public and private, the physical and virtual, imagined and real, past and present, author and audience. I view this relationship as crucial to understanding the shift in the role of the audience from passive receivers of content to active producers ('Mobile Produsers'). Further, I argue that the diverse contexts of mobile content production and the definition of the content itself have become the central means by which mobile phone practices are emerging. I draw on anthropology, social science and media studies in order to explore the impact of mobile contexts, content, and use on identity. I propose that this approach allows for a new understanding of mobile practices as a form of spectacle, especially what I refer to as the spectacle of the self. Produsership theory informs an understanding of mobile practices, content production and performance, and the Bahktinian concept of carnival becomes a useful term in analysing the mobile as both performance and spectacle. Through an analysis of mobile content within cinematic culture, social interaction, and mixed media environments I consider the ways in which the mobile functions not only as a tool for positioning the individual, but also as performing an integral part in a multi-user process of mobile content production. In this sense, mobile content can be understood as a map, and the mobile as a compass used by the produser to navigate the mobile?s diverse contexts. Furthermore, I demonstrate that mobile content is collectively constructed while being individually absorbed. It is reflective of both the context and its user and open to constant questioning and interpretation, which is then shared with others. Finally, this thesis explores the notion of being t/here as mode of participating with the mobile in time and space, where one's identity is distributed across virtual and physical spaces, simultaneously locating the user as both here and there (t/here).

University of Macau / Faculty of Business Administration / Department of Management and Marketing

In this thesis I explore the relationship between the mobile phone and its user and argue that this relationship is crucial in merging the contexts of public and private, the physical and virtual, imagined and real, past and present, author and audience. I view this relationship as crucial to understanding the shift in the role of the audience from passive receivers of content to active producers ('Mobile Produsers'). Further, I argue that the diverse contexts of mobile content production and the definition of the content itself have become the central means by which mobile phone practices are emerging. I draw on anthropology, social science and media studies in order to explore the impact of mobile contexts, content, and use on identity. I propose that this approach allows for a new understanding of mobile practices as a form of spectacle, especially what I refer to as the spectacle of the self. Produsership theory informs an understanding of mobile practices, content production and performance, and the Bahktinian concept of carnival becomes a useful term in analysing the mobile as both performance and spectacle. Through an analysis of mobile content within cinematic culture, social interaction, and mixed media environments I consider the ways in which the mobile functions not only as a tool for positioning the individual, but also as performing an integral part in a multi-user process of mobile content production. In this sense, mobile content can be understood as a map, and the mobile as a compass used by the produser to navigate the mobile?s diverse contexts. Furthermore, I demonstrate that mobile content is collectively constructed while being individually absorbed. It is reflective of both the context and its user and open to constant questioning and interpretation, which is then shared with others. Finally, this thesis explores the notion of being t/here as mode of participating with the mobile in time and space, where one's identity is distributed across virtual and physical spaces, simultaneously locating the user as both here and there (t/here).