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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Investigation of mechanisms for routing in mobile ad-hoc network

Bakht, Humayun January 2006 (has links)
No description available.
72

Architecture and remote interaction techniques for digital media exchange across 3G mobile devices

Yousef, Kharsim January 2009 (has links)
For users away from the office or home, there is an increasing demand for mobile solutions that offer effective collaborative facilities on the move. The mobile cellular device, or “smart phone”, can offer a ubiquitous platform to deliver such services, provided that its many physical and technological constraints can be overcome. In an effort to better support mobile collaboration, this thesis presents a contributing Mobile Exchange Architecture (MEA) designed to improve upon the capabilities provided by mobile devices to enable synchronous exchange of digital media during a phone conversation using wireless networks and cellular devices. This research includes the design and development of one such MEA in the form of a fully functional Photo-conferencing service, supporting shared remote interaction techniques, simultaneous voice communication and seamless digital media exchange between remote and collocated mobile users. Furthermore, through systematic design, experimental evaluations and field studies we evaluate the effects of different shared remote interaction techniques – 'pointing', 'scaling', 'mixed' and 'hybrid' – assessing the task effort required by users when interacting around shared images across resource constrained mobile devices. This thesis presents a direction for the future development of technologies and methods to enable a new era of scalable always-to-hand mobile collaborative environments.
73

Frequency hopping techniques for digital mobile radio / Simon C. Rockliff

Rockliff, Simon C. (Simon Charles) January 1990 (has links)
Bibliography: leaves [205]-213 / viii, 214 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, 1991
74

An architecture for mobile communications in hazardous situations and physical disasters

Soulahakis, Alexander January 2007 (has links)
Hazardous environmental conditions have always been a threat to human lives around the globe. Human society has seen some of the worst disasters due to accidents, physical phenomena or even cases that humans have created on purpose. The existing infrastructure can guarantee that there are hospitals, markets, mass transportation networks, sophisticated communications networks, and many more to cover all possible needs from a home user to an enterprise company. Unfortunately, the infrastructure has been proven unstable due to rapid environmental changes. The sophisticated networks, as well as the support buildings, can become useless in seconds in the event of a physical phenomenon such as an earthquake, a fire or a flood or even worse in the event of a well organized terrorist attack. The major problems identified are associated with inadequate capacity of the network, equipment vulnerable to physical phenomena and methodologies of disaster recovery that require time and work force to be applied. Modem telecommunication systems are designed in a cost effective way, to support as many users as they can, by using minimum equipment, but they cannot support users in hazardous environments. As a response to this situation we present the development of a novel architecture, which is based on an fast deployed network, infrastructure independent. The proposed network is capable of providing mobile subscribers with messaging and voice services in hazardous environments at the time of the event. Similar studies are based on infrastructure as they are in the need of extra hardware deployment. The novelty of our research is that we combine 802.11 and GSM in order to form a fast deployed network, infrastructure independent. The proposed architecture has two modes of operation: messages only or voice system. This solution benefits from the advantages of a deployed, infrastructure independent Ad Hoc network. This network is able to recover quickly from errors and can survive in hazardous dynamic environments. In addition we benefit from GSM technology using already implemented functions such as encoding/decoding for voice transmission. Combining those two technologies we can deploy a network which satisfies the challenges previously mentioned. While 802.11 handles connectivity and data transfers, GSM is responsible for bit error correction of voice calls and a number of other functions such as messaging and identification. The proposed architecture has been designed and simulated in order to evaluate the network. The evaluation has been separated in two phases. Messaging and voice capabilities of the network have been tested to investigate their performance. In the evaluation we check the factors affecting the network in a hazardous environment and we compare it to other approaches and similar networks. The results prove that the concept of messaging service is valid as the system can operate in hazardous environments. Voice capabilities of the system have been proven to work but further work is needed for maximising the performance and the reliability of the network. The new architecture can form the basis for the next generation emergency telecommunication services.
75

A model for representing the motivational and cultural factors that influence mobile phone usage variety

Van Biljon, Judith Arnoldine 30 November 2006 (has links)
Mobile phone usage involves the mobile phone, the telecommunications system, mobile phone users, and the adoption and use of the system. Mobile communications is a complex and rapidly changing industry consisting of the hardware, software, network and business aspects. Mobile phone users are influenced by demographic, social, cultural and contextual factors that complicate the understanding of mobile phone usage. Advances in technology and market competition drive the addition of new services and features. In contrast, human cognition and attention are more constrained and many users find it difficult to cope with the cognitive demands of mobile phone technology. The aim of this study is to develop a model for representing the influence of motivational needs and cultural factors on mobile phone usage variety. The link between motivational needs and mobile phone usage variety, the cultural factors that influence mobile phone usage variety, as well as usage spaces as an approach to representing usage variety, are researched. The research encompasses a literature study, structured interviews, a pilot study and a survey. The pilot study and survey yielded data about mobile phone usage of university students under the age of 30 in South Africa. The results from the statistical analysis were triangulated with the findings of the literature study and the observations made about mobile phone usage during this two-year period. A final survey was conducted to verify the model. The contribution of this study is a mobile phone technology usage model (MOPTUM) for representing the motivational and cultural factors that influence mobile phone usage variety in such a way that users can use the model to express their mobile phone usage needs in non-technical terms while marketers and designers can use the model to convert the expressed user needs into the features required. MOPTUM draws on concepts and models from sociology, computer-supported cooperative work, human-computer interaction and technology adoption models from the field of marketing. MOPTUM verifies some existing findings on mobile phone usage and then integrates and extends these existing models to provide a new model for understanding the motivational and cultural factors that influence mobile phone usage variety. / Computing / Ph. D. (Computer Science)
76

A model for representing the motivational and cultural factors that influence mobile phone usage variety

Van Biljon, Judith Arnoldine 30 November 2006 (has links)
Mobile phone usage involves the mobile phone, the telecommunications system, mobile phone users, and the adoption and use of the system. Mobile communications is a complex and rapidly changing industry consisting of the hardware, software, network and business aspects. Mobile phone users are influenced by demographic, social, cultural and contextual factors that complicate the understanding of mobile phone usage. Advances in technology and market competition drive the addition of new services and features. In contrast, human cognition and attention are more constrained and many users find it difficult to cope with the cognitive demands of mobile phone technology. The aim of this study is to develop a model for representing the influence of motivational needs and cultural factors on mobile phone usage variety. The link between motivational needs and mobile phone usage variety, the cultural factors that influence mobile phone usage variety, as well as usage spaces as an approach to representing usage variety, are researched. The research encompasses a literature study, structured interviews, a pilot study and a survey. The pilot study and survey yielded data about mobile phone usage of university students under the age of 30 in South Africa. The results from the statistical analysis were triangulated with the findings of the literature study and the observations made about mobile phone usage during this two-year period. A final survey was conducted to verify the model. The contribution of this study is a mobile phone technology usage model (MOPTUM) for representing the motivational and cultural factors that influence mobile phone usage variety in such a way that users can use the model to express their mobile phone usage needs in non-technical terms while marketers and designers can use the model to convert the expressed user needs into the features required. MOPTUM draws on concepts and models from sociology, computer-supported cooperative work, human-computer interaction and technology adoption models from the field of marketing. MOPTUM verifies some existing findings on mobile phone usage and then integrates and extends these existing models to provide a new model for understanding the motivational and cultural factors that influence mobile phone usage variety. / Computing / Ph. D. (Computer Science)
77

The licence as a mechanism to improve performance : the case of Cell C

Dippenaar, Jacques Roché 11 1900 (has links)
The licence is a regulatory tool that regulatory use to assist in their regulatory functions. Licences restricts operator’s’ functions, but also serve as a guideline of acceptable conduct because a licence is a legally binding document containing prescribed conditions that the licencee must meet. If the licencee does not comply with these prescribed obligations and requirements, the licence may be revoked or the licencee may be penalized (Bladwin & Cave 1999). However, in order fro the mechanism of issuing a licence to be an effective mechanism of regulation, the regulator needs to regulate effectively in order to ensure that the licencee’s performance is of acceptable standard. The purpose of this study is to investigate the relationship between issuing a licence and the licencee’s performance; to investigate whether the performance indicators, as defined by ICASA, are adequate, and to develop appropriate performance indicators in order to evaluate Cell C’s performance. Issuing a licence to licencee does not guarantee that the performance of the licencee, such as Cell C, will be effective. Thus, the licencee needs to be evaluated. The case study design has been used for this project. The methodology includes in-dept interviews, documentary analysis, and implementation evaluation research. The report concludes that Cell C has met its licence obligations, that licencing is coupled with effective mechanisms to ensure that the licencee complies with performance requirements, but that, in order for the licencee to improve its performance, effective regulatory intervention is needed. / Communication Science / MA (International Communication)
78

The licence as a mechanism to improve performance : the case of Cell C

Dippenaar, Jacques Roché 11 1900 (has links)
The licence is a regulatory tool that regulatory use to assist in their regulatory functions. Licences restricts operator’s’ functions, but also serve as a guideline of acceptable conduct because a licence is a legally binding document containing prescribed conditions that the licencee must meet. If the licencee does not comply with these prescribed obligations and requirements, the licence may be revoked or the licencee may be penalized (Bladwin & Cave 1999). However, in order fro the mechanism of issuing a licence to be an effective mechanism of regulation, the regulator needs to regulate effectively in order to ensure that the licencee’s performance is of acceptable standard. The purpose of this study is to investigate the relationship between issuing a licence and the licencee’s performance; to investigate whether the performance indicators, as defined by ICASA, are adequate, and to develop appropriate performance indicators in order to evaluate Cell C’s performance. Issuing a licence to licencee does not guarantee that the performance of the licencee, such as Cell C, will be effective. Thus, the licencee needs to be evaluated. The case study design has been used for this project. The methodology includes in-dept interviews, documentary analysis, and implementation evaluation research. The report concludes that Cell C has met its licence obligations, that licencing is coupled with effective mechanisms to ensure that the licencee complies with performance requirements, but that, in order for the licencee to improve its performance, effective regulatory intervention is needed. / Communication Science / MA (International Communication)

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