Thesis (Ph.D.(Electrical Engineering)--University of Pretoria, 2004. / Summaries in Afrikaans and English. Includes bibliographical references.

The dangers of using a cell phone while driving are well documented, but recently studies have aimed at determining the effect cell phones have on a pedestrians’ walking behaviors. This observational experiment captured video footage of distracted pedestrians, or pedestrians using cell phones, when using two different crosswalks (midblock and intersection) on the campus of Mississippi State University in order to study safety behaviors, such as speed, number of looks, and wait time. Two types of crosswalks were filmed until a sufficient number of pedestrians (N=982) were recorded. All variables (cell phone use, gender, type of crosswalk, presence of car, time of day, and density) significantly influenced speed and number of looks. Gender, type of crosswalk and presence of car all showed significant effects on wait time of pedestrians. Pedestrians observed using earphones were observed to look more and to walk slower than any other level of cell phone use.

No description available.

Performance analysis in cellular networks is the determination of customer orientated grade-of-service parameters, such as call blocking and dropping probabilities, using the methods of stochastic theory. This stochastic theory analysis is built on certain assumptions regarding the arrival and service processes of user-offered calls in a network. In the past, cellular networks were analysed using the classical assumptions, Poisson call arrivals and negative exponential channel holding times, borrowed from earlier fixed network analysis. However, cellular networks are markedly different from fixed networks, in that, they afford the user a unique opportunity: the ability to communicate while on the move. User mobility and various other cellular network characteristics, such as customer-billing, cell· layout and hand·off mechanisms, generally invalidate the use of Poisson arrivals and negative exponential holding times. Recent measurements on live networks substantiate this view. Consequently, over the past few years, there has been a noticeable shift towards using more generalised arrival and service distributions in the performance analysis of cellular networks. However, two shortcomings with the resulting models are that they suffer from state space explosion and / or they represent hand off traffic as a state dependent mean arrival rate (thus ignoring the higher moments of the hand-off arrival process). This thesis's contribution to cellular network analysis is a moment-based approach that avoids full state space description but ensures that the hand-off arrival process is modelled beyond the first moment. The thesis considers a performance analysis model that is based on Poisson new call arrivals, generalised hand-off call arrivals and a variety of channel holding times. The thesis shows that the performance analysis of a cellular network may be loosely decomposed into three parts, a generic cell traffic characterising model, a generic cell traffic blocking model and a quality of service evaluation model. The cell traffic characterising model is employed to determine the mean and variance of hand-off traffic offered by a cell to its neighbour. The cell traffic-blocking model is used to detennine the blocking experienced by the various traffic streams offered to each cell. The quality of service evaluation part is essentially afued-point iteration of the cell traffic characterising and cell traffic blocking parts to determine customer orientated grade-of-service parameters such as blocking and dropping probabilities. The thesis also presents detailed mathematical models for user mobility modelling. Finally, the thesis provides extensive results to validate the proposed analysis and to illustrate the accuracy of the proposed analysis when compared to existing methods. / Thesis (Ph.D.)-University of Natal, Durban, 2000.

While experiencing exponential growth worldwide, Information and Communication Technologies (ICTs) are key factors in business today. The ubiquitous nature of the mobile phone in South Africa and the use of wireless technologies facilitate business in areas where current fixed infrastructure is limited or non-existent, thereby aiding in the development of rural areas. This descriptive study determines what factors will extend the use of mobile phone technology in business. The literature indicates business advantage can be gained from incorporating technology into a strategic framework but in so doing must consider the complexities of the technology and its lifecycle. Currently, e-mail and Internet access would be the most likely applications of data use via Global System for Mobile Communications (GSM). As a technology-based study the methodology used e-mail to deliver a survey targeting staff from the three cellular network operators in Port Elizabeth. The mobile industry and Port Elizabeth were both considered good indicators of technology use and the progression of infrastructure throughout South Africa. The findings indicate that although most mobile phones have the features required by users, the current use of associated data applications is low. Email is the most appropriate application and expected to be significant in 2006. The technology is of strategic importance and can be applied to make idle time productive. Successful use depends on the removal of barriers. In the case of e-mail and Internet access; the most significant of these is the complexity of the initial set-up. Despite the complexity of technology evolution and the challenges of effective business application, substantial gains can be still be realised. Currently, technology is best deployed to meet specialised needs. The expected introduction of third generation technologies herald’s higher data transfer rates, providing the opportunity for more generalised application in business in the immediate future.

The topic of this thesis is "Psychosocial effects of the use of mobile phones in children under the age of 12 years." Children in connection with the use of mobile phones are more vulnerable compared to adults regarding the unwilling behavior. Czech public (neither lay nor professional) has not paid sufficient attention to this issue so far. The aim of this work was to monitor attitudes of children to mobile phones, the manner and extent of their use. At last but not at least, it was also the aim to describe the position of mobile service providers to child customers. There was also a market analysis carried out to describe offers, products and services suitable for children. The first part of this thesis describes the current situation in the Czech Republic and is complemented with statistical data of the numbers of mobile phones in the Czech Republic. There are also specifics of children as users of mobile phones mentioned and the risks that are connected to the use of mobile phones, such as reliance on mobile or nomophobia, fears of loss of signal etc. In the following chapters objectives of the research are described, hypotheses and research methodology. The results are shown in graphical form. They are followed by the results of market analysis and expert observations on the issue, the methodology and the research itself. The last part of this thesis is the discussion on the methodology and research results. Research results are also compared and discussed in relation to the literature.

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

Public mobile phone use is often viewed negatively, although the reason for these negative perceptions is unclear. The current study examined perceptions of public mobile phone users in a 2 X 2 factorial design. Participants viewed a staged video of a public conversation that was either face-to-face or over a mobile and later rated their perception of the conversation and target speaker. Two variables were manipulated: whether participants could hear both sides or only one side of the conversation, and whether the conversation took place over a mobile phone or was face-to-face. The results indicated that the one side mobile phone conversation was more noticeable, intrusive, and annoying to overhear compared to the two-sided mobile speaker phone conversation and one side inaudible face-to-face conversation. Additionally, participants indicated that the target speaker in the one side mobile phone conversation was liked less than the target speaker in the mobile speaker phone condition and was perceived as more extroverted when participants could only hear one side of the conversation. The findings from this study are discussed in relation to previous data as to why public mobile phone conversations are generally perceived negatively by others. / Department of Psychological Science

M.Sc.(Eng.), Faculty of Engineering and the Built Environment, 2011 / The main objective of seamless mobility is to enable mobile users to stay connected while roaming across heterogeneous networks. As cellular networks evolve from the third generation Universal Mobile Telecommunication System (UMTS) to the Long Term Evolution (LTE), a new Evolved Packet Core (EPC) will support heterogeneous radio access networks on the same platform. UMTS provides voice services in the circuit switched domain; while LTE operates in the packet switched domain. Cellular network operators thus face the challenge of providing voice services during initial deployment of LTE due to difficulty in mobility between the two domains. Seamless voice handover between packet switched LTE and the circuit switched UMTS network is therefore an important tool in solving this problem. This report investigates the performance of inter-Radio Access Technology voice handover between LTE and UMTS. The schemes evaluated were Voice Call Continuity (VCC) for UMTS to LTE handover and Single Radio Voice Call Continuity (SRVCC) for LTE to UMTS handover. The performance evaluation was done using mathematical models and equations that were derived for the handover service interruption time. The resulting equations were simulated and the output was analysed and compared with the Third Generation Partnership Project (3GPP) specifications.

Thesis (M.M. (ICT Policy and Regulation))--University of the Witwatersrand, Faculty of Commerce, Law and Management, Graduate School of Public and Development Management, 2013. / Cannot copy abstract.