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.

The effects that cellular (cell) phone conversation may have on pedestrian road-crossing performance is unknown. A series of experiments was conducted using a virtual reality road crossing simulator to examine this issue. The participants were primarily university students aged between 18 and 24 years old, although one study compared a group aged 18 to 24 to a group between 50 and 67 years old. Two experimental situations were used: a gap-choice situation, in which the participants had to choose a gap to cross through; and an infrequency situation, where vehicles were present on only 10% of the trials. Participants were impaired by a simulated phone conversation task when compared to no-conversation task, as evidenced by longer reaction times, slower walking speeds, poorer gap choices, and more cautious behaviours. Most importantly, conversation was related to a decrease in the mean margins of safety, and the participants were hit or nearly hit by vehicles more often when talking. The general performance of the older participants did not differ from that of the younger participants, and both groups were impaired to a similar extent by the conversation task. Participants were found to use irrelevant distance information to inform their gap-choice decisions, a strategy associated with a decrease in safety as the distance between the vehicles increased. It was also found that their use of time-to-arrival information was impaired when engaged in the conversation task. Overall, talking on a cell phone while crossing a road may represent an unnecessary increase in risk; therefore, care should be taken if these two acts are being conducted concurrently.

abstract: ABSTRACT This study evaluated the LoseIt Smart Phone app by Fit Now Inc. for nutritional quality among users during an 8 week behavioral modification weight loss protocol. All participants owned smart phones and were cluster randomized to either a control group using paper and pencil record keeping, a memo group using a memo function on their smart phones, or the LoseIt app group which was composed of the participants who owned iPhones. Thirty one participants completed the study protocol: 10 participants from the LoseIt app group, 10 participants from the memo group, and 11 participants from the paper and pencil group. Food records were analyzed using Food Processor by ESHA and the nutritional quality was scored using the Healthy Eating Index - 2005 (HEI-2005). Scores were compared using One-Way ANOVA with no significant changes in any category across all groups. Non-parametric statistics were then used to determine changes between combined memo and paper and pencil groups and the LoseIt app group as the memo and paper and pencil group received live counseling at biweekly intervals and the LoseIt group did not. No significant difference was found in HEI scores across all categories, however a trend was noted for total HEI score with higher scores among the memo and paper and pencil group participants p=0.091. Conclusion, no significant difference was detected between users of the smart phone app LoseIt and memo and paper and pencil groups. More research is needed to determine the impact of in-person counseling versus user feedback provided with the LoseIt smart phone app. / Dissertation/Thesis / M.S. Nutrition 2011

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.

La thèse porte sur la quantification d'incertitude de paramètres (Uncertainty Quantification ou UQ) dans le calcul du débit d'absorption spécifique (Specific Absorption Rate ou SAR) de téléphones mobiles. L'impact de l'incertitude, ainsi le manque de connaissances détaillées sur les propriétés électriques des matériaux, les caractéristiques géométriques du système, etc., dans le calcul SAR est quantifiée par trois méthodes de calcul efficaces dites non-intrusives : Transformation non parfumée (Unscented Transformation ou UT), collocation stochastique (Stochastic Collocation ou SC) et polynômes de chaos non-intrusifs (Non-Intrusive Polynomial Chaos ou NIPC).Ces méthodes sont en effet appelées méthodes non intrusives puisque le processus de simulation est tout simplement considéré comme une boîte noire sans que ne soit modifié le code du solveur de simulation. Leurs performances pour les cas de une et deux variables aléatoires sont analysées dans le présent travail. En contraste avec le procédé d'analyse d'incertitude traditionnel (la méthode de Monte Carlo ou MCM), le temps de calcul devient acceptable. Afin de simplifier la procédure UQ pour le cas de plusieurs entrées incertaines, il est démontré que des incertitudes peuvent être combinées de manière à évaluer l'incertitude sur les paramètres de la sortie.Combiner des incertitudes est une approche généralement utilisée dans le domaine des mesures, et ici, il est utilisé dans le calcul du SAR pour la situation complexe. Une des étapes nécessaires dans le cadre de l'analyse d'incertitude est l'analyse de sensibilité (Sensitivity Analysis ou SA), qui vise à quantifier l'importance relative de chaque paramètre d'entrée incertain par rapport à l'incertitude de la sortie. La méthode reposant sur le calcul des indices de sensibilité de Sobol est employée, ces indices étant évalués par un développement en polynômes de chaos, au lieu d'utiliser la méthode de Monte-Carlo dans le calcul SAR. Les résultats des investigations sont présentés et discutés.Afin de faciliter la lecture, des notions élémentaires de débit d'absorption spécifique, de modélisation, d'incertitude dans la modélisation, de théorie des probabilités, et de calcul SAR par l'un des solveurs de simulation sont proposés dans l'Introduction (chapitre 1). Puis l'usage des méthodes non-intrusives UQ telles que UT, SC et NIPC, et l'application de la méthode des indices de Sobol pour l'analyse de sensibilité dans le calcul SAR est présentée dans les chapitres 2 et 3. Dans le chapitre 4, une autre approche d'utilisation des polynômes de chaos est fournie, et elle est utilisée dans le domaine temporel par l'intermédiaire d'un code de différences finies (Finite Difference-Time Domain ou FD-TD). Puisque le code FD-TD dans le solveur de simulation peut en effet être modifié, c'est le développement en polynômes de chaos intrusifs, étudié en détail par un certain nombre de scientifiques déjà, qui est considéré. Dans le chapitre 5, les conclusions et un aperçu des travaux futurs sont fournis. / This thesis focuses on parameter uncertainty quantification (UQ) in specific absorptionrate (SAR) calculation using a computer-aided design (CAD) mobile phone model.The impact of uncertainty, e.g., lack of detailed knowledge about material electricalproperties, system geometrical features, etc., in SAR calculation is quantified by threecomputationally efficient non-intrusive UQ methods: unscented transformation (UT),stochastic collocation (SC) and non-intrusive polynomial chaos (NIPC). They are callednon-intrusive methods because the simulation process is simply considered as a blackboxwithout changing the code of the simulation solver. Their performances for thecases of one and two random variables are analysed. In contrast to the traditionaluncertainty analysis method: Monte Carlo method, the time of the calculation becomesacceptable. To simplify the UQ procedure for the case of multiple uncertain inputs, it isdemonstrated that uncertainties can be combined to evaluate the parameter uncertaintyof the output. Combining uncertainties is an approach generally used in the field ofmeasurement, in this thesis, it is used in SAR calculations in the complex situation. Oneof the necessary steps in the framework of uncertainty analysis is sensitivity analysis (SA)which aims at quantifying the relative importance of each uncertain input parameterwith respect to the uncertainty of the output. Polynomial chaos (PC) based Sobol’indices method whose SA indices are evaluated by PC expansion instead of Monte Carlomethod is used in SAR calculation. The results of the investigations are presented anddiscussed.In order to make the reading easier, elementary notions of SAR, modelling, uncertaintyin modelling, and probability theory are given in introduction (chapter 1). Thenthe main content of this thesis are presented in chapter 2 and chapter 3. In chapter 4,another approach to use PC expansion is given, and it is used in the finite-differencetime-domain (FDTD) code. Since the FDTD code in the simulation solver should bechanged, it is so-called intrusive PC expansion. Intrusive method already investigatedin details in other people’s thesis. In chapter 5, conclusions and future work are given.

The West Virginia Prescription Drug Abuse Quitline (WVPDAQ) is a resource that offers education and support to individuals and families affected by prescription drug abuse. The WVPDAQ began functioning September 11, 2008, through the use of mobile phone and laptop technology. Although some helplines and quitlines use some aspects of remote technology, most function through traditional call center and landline technology, making the WVPDAQ unique. This article describes the process evaluation of the WVPDAQ and outlines both the positive findings and challenges faced by the WVPDAQ. Lessons learned and future recommendations for remote quitline endeavors are also presented. It is hoped that the experiences and information regarding the WVPDAQ presented can provide best-practice insight for public health practitioners and evaluation personnel who are considering using alternative technologies to deliver quitline services.

Malaria significantly contributes to morbidity and mortality rates in Zambia. The currently accepted malaria treatment is artemisinin-based combination therapy (ACT); it is more than 97% effective when the regimen is strictly adhered to. However, the mean ACT adherence rate in sub-Saharan Africa is only approximately 38-48%. Poor pharmacoadherence remains a significant barrier to malaria control and elimination. The purpose of this study was to determine if adherence rates to a six-dose ACT antimalarial treatment differ between patients in Zambia who received short message service (SMS) reminders and those who did not. An experimental, randomized, controlled trial was conducted to collect data from a sample of 96 adult patients with malaria who presented to Fisenge Clinic in the Copperbelt Province of Zambia. Participants were randomly assigned to a control or intervention group. The intervention group received SMS messages to remind them to take their medication according to the regimen. An electronic pillbox was used to measure pharmacoadherence for both groups, and patients were classified as probably adherent or probably non-adherent. Data were analyzed using Chi-square for association between the SMS intervention and pharmacoadherence, and logistic regression used for predictors of adherence. No significant association was found between SMS reminders and pharmacoadherence among malaria patients being treated with ACT when evaluated with respect to those who received the SMS reminders and those who did not (x2=0.19, df=1, p=0.67). Binary logistic regression indicated that there were no variables associated with adherence (p > 0.05). Findings from this study contribute to the research regarding the use of mobile phones to promote adherence. This is the first study of its kind using SMS directly to the patient for ACT adherence in sub-Saharan Africa known to the author. It is possible that the use of the electronic pillbox and/or the novelty of participating in a research study contributed to higher levels of adherence than previously found in this geographical area. While data suggested that there was no association between SMS and adherence, further research is needed to explore the value of this intervention.

No description available.

Mobile phone use while in the presence of physical conversational partners is a reality in modern day life. Many researchers have investigated how different subgroups use mobile phones and the consequences of such use. The goal of this research was to determine how mobile phones are used in social settings when face-to-face conversations are taking place. The main questions that the research attempted to solve were: (1) If the phone use was related to the conversation at hand, (2) if the intensity of phone use was correlated to how the phone was used, (3) and if phones are used during conversations in different ways depending on the relationships and demographics of the conversational partners. The research was conducted in Malmö, Sweden at bars and cafes´ by administering a semi structured verbal interview on people seen using their cell phones while in face-to-face conversations. Relevant demographic information was recorded as well as five open ended questions. The questions were aimed at understanding how the phone was used, and the phones use in relation to the physical conversation. The research was conducted using the research paradigm of Positivism and the data was analyzed using an Inductive research strategy. Uses and Gratifications theory was the main theory that this research was viewed through. In addition, relevant information was drawn from various psychological theories as well as problematic mobile phone research. The findings show that the majority of phone use is unrelated to the conversations at hand. But often this phone use is re-integrated into the conversation at a later time. It was also found that phone use related to information retrieval was most likely to be related to the face-to-face conversation. Additionally, the data showed that conversational partners that use the phone a lot are highly unlikely to be using the phone in relation to the conversation. The data showed that friends are most likely to not use the phone in relation to the conversation.

This thesis investigates drivers willingness to engage with a mobile phone while driving. Many studies have looked into the effects on driving performance that can result from phone usage, but few studies have directly considered what can encourage or inhibit phone engagement behaviours in the first place. An initial exploratory study (Study 1) was conducted, for which a photo elicitation interview (N=20) was designed and implemented. This aimed to find the extent to which factors influencing phone use transferred from out of the car to the driving environment. In particular, the study aimed to explore whether the driving environment could be considered unique. The results indicated that the high demands placed on the driver by the road environment clearly distinguished it from the other environments and the reported propensity to use a phone seemed to reflect this. Only factors which either changed the level of attention required by the task, such as a change in task demand as a result of changes in the traffic environment, had any substantial influence on willingness to engage. Driving may not be unique in terms of the overall factors influencing phone use but it is unique in the extent to which this particular factor seems to have such a strong bearing on interaction. Building on findings from Study 1, that the demand and attention required seemed to influence willingness to engage, it was noted that Fuller s (2005) Task Capability Interface model would serve as a useful framework for the remainder of the thesis. This model suggests that driver behaviour is dictated by the level of task difficulty perceived; an interaction between task demand and capability. Therefore, the effects these two elements might have on willingness to engage with mobile phones while driving were tested separately in the two remaining studies. Previous research suggested that task demand should comprise a combination of roadway demand and the intended phoning task. Study 2, therefore, experimentally tested the extent to which road demand and phone function intended to be used influenced drivers decisions to engage with their phone. Participants (N=20) viewed video clips of real road environments of varying demand. Rating scales were used by participants to rate their willingness to engage with various phone functions according to the scenario they had just viewed. It was found both roadway demand and phone functionality affected willingness to engage with a mobile phone whilst driving. There was a higher propensity to engage in phone use in road environments perceived to have a lower demand and lower propensity to engage in phone use in the highest demand scenarios. Answering a call was the most likely function to be engaged with by the participants and sending a text message was the least likely. The final study investigated how capability (comprising both phone and driving capability) influenced willingness to engage. Participants (N=40) were required to drive in a simulator under two conditions, simulated low and high road demand. Their willingness to interact with their phones, when faced with a number of phone tasks, was then observed. It was found that driving capability had an effect on willingness to engage in high demand scenarios with the less capable, novice, drivers having a higher propensity to engage with placing a call, sending a text message and reading a text message than the more experienced drivers. Novice drivers were willing to engage with some functions on their phone at possibly inappropriate times. It was further found that, in the simulated low demand road environment, phone capability influenced willingness to engage, with those who were more capable at placing a call and sending a text message found to be more willing to engage with these functions. The research reported in this thesis represents the first attempt in the literature to study, in depth, the factors which can influence phone engagement behaviour while driving. Novel contributions include investigating if factors influencing phone use transferred from out of the car to the driving environment. Further novel contributions included whether the phone function and road demand interact to influence willingness to engage and whether capability can affect phone engagement behaviour while driving. Extending the model developed by Fuller, the thesis offers an original model that describes the factors affecting phone engagement behaviour while driving. Suggestions are proposed for how the findings presented in this thesis can effectively be used and how future work should build on these initial foundations.