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Context-aware computing aims at making mobile devices sensitive to the social and physical settings in which they are used. A necessary requirement to achieve this goal is to enable those devices to establish a shared understanding of the desired settings. Establishing a shared understanding entails the need to manipulate sensed data in order to capture a real world situation wholly, conceptually, and meaningfully. Quite often, however, the data acquired from sensors can be inexact, incomplete, and/or uncertain. Inexact sensing arises mostly due to the inherent limitation of sensors to capture a real world phenomenon precisely. Incompleteness is caused by the absence of a mechanism to capture certain real-world aspects; and uncertainty stems from the lack of knowledge about the reliability of the sensing sources, such as their sensing range, accuracy, and resolution. The thesis identifies a set of criteria for a context-aware system to capture dynamic real-world situations. On the basis of these criteria, a distributed architecture is designed, implemented and tested. The architecture consists of Primitive Context Servers, which abstract the acquisition of primitive contexts from physical sensors; Aggregators, to minimise error caused by inconsistent sensing, and to gather correlated primitive contexts pertaining to a particular entity or situation; a Knowledge Base and an Empirical Ambient Knowledge Component, to model dynamic properties of entities with facts and beliefs; and a Composer, to reason about dynamic real-world situations on the basis of sensed data. Two additional components, namely, the Event Handler and the Rule Organiser, are responsible for dynamically generating context rules by associating decision events ? signifying a user?s activity ? with the context in which those decision events are produced. Context-rules are essential elements with which the behaviour of mobile devices can be controlled and useful services can be provided. Four estimation and recognition schemes, namely, Fuzzy Logic, Hidden Markov Models, Dempster-Schafer Theory of Evidence, and Bayesian Networks, are investigated, and their suitability for the implementation of the components of the architecture of the thesis is studied. Subsequently, fuzzy sets are chosen to model dynamic properties of entities. Dempster-Schafer?s combination theory is chosen for aggregating primitive contexts; and Bayesian Networks are chosen to reason about a higher-level context, which is an abstraction of a real-world situation. A Bayesian Composer is implemented to demonstrate the capability of the architecture in dealing with uncertainty, in revising the belief of the Empirical Ambient Knowledge Component, in dealing with the dynamics of primitive contexts and in dynamically defining contextual states. The Composer could be able to reason about the whereabouts of a person in the absence of any localisation sensor. Thermal, relative humidity, light intensity properties of a place as well as time information were employed to model and reason about a place. Consequently, depending on the variety and reliability of the sensors employed, the Composer could be able to discriminate between rooms, corridors, a building, or an outdoor place with different degrees of uncertainty. The Context-Aware E-Pad (CAEP) application is designed and implemented to demonstrate how applications can employ a higher-level context without the need to directly deal with its composition, and how a context rule can be generated by associating the activities (decision events) of a mobile user with the context in which the decision events are produced.

Text in English / The role that locally relevant services and content can play in the development of societies cannot be underestimated. The proliferation of mobile phones in Africa’s developing countries is a significant enabler, which provides access to such locally relevant services and content. Mobile applications have the potential to support the development of the African continent through bolstering the main mechanisms of innovation, inclusion and efficiency. This has been demonstrated by instances of increased literacy, improved access to health care, banking, crowd sourcing and provision of farming and/or agricultural assistance. Successful cases of such mobile-based services include Kenya’s M-Pesa, which has allowed millions of rural people, who do not have access to traditional banking facilities, to send and receive money as well as pay utility bills and school fees. The development of similar innovative and locally relevant mobile-based solutions, which is currently considered to be in its infancy, is key to improving the lives of people in developing countries. This study identifies the essential components of an innovation ecosystem, for the development and presentation of a Mobile Applications Innovation Ecosystem Framework for Botswana. An innovation ecosystem enables effective interaction amongst entrepreneurs, companies, universities, research organisations, investors and government agencies towards maximising economic impact and potential. To gain a practical understanding of the context in which locally relevant mobile-based services can be developed, the study adopted a pragmatic research approach. Through combining the 4Cs Framework for ICT and the systems theory’s Triple Helix Model of Innovation, the study proceeded to develop the framework using a Design Science Research (DSR) methodology. DSR guided the identification of the components, which make up the mobile applications innovation ecosystem within government, industry and higher education sectors, as extracted from the literature review. This process facilitated initial framework designs, which were demonstrated to and evaluated by conveniently sampled stakeholders from relevant helices. Thereafter a synthesised framework was presented for evaluation by knowledgeable professionals from the mobile applications innovation ecosystem. The study contributes to the theoretical knowledgebase by presenting a theoretical framework for understanding ICT4D innovation frameworks and mobile applications / School of Computing / Ph. D. (Information Systems)

Over the past few years, there has been a skyrocketing growth in the use of mobile devices. Mobile devices are ushering in a new era of multi-platform media and a new paradigm of “being-always-connected”. The proliferation of mobile devices, the dramatic growth of cloud computing services, the availability of high-speed mobile internet, and the increase in the functionalities and network connectivity of mobile devices, have led to creation of a phenomenon called BYOD (Bring Your Own Device), which allows employees to connect their personal devices to corporate networks. BYOD is identified as one of the top ten technology trends in 2014 that can multiply the size of mobile workforce in organizations. However, it can also serve as a vehicle that transfers cyber security threats associated with personal mobile devices to the organizations. As BYOD opens the floodgates of various device types and platforms into organizations, identifying different sources of cyber security threats becomes indispensable. So far, there are no studies that investigated how user, device and usage characteristics affect individuals’ protective and risky IT behaviors. The goal of this dissertation is to expand the current literature in IS security by accounting for the roles of user, device, and usage characteristics in protective and risky IT behaviors of individuals. In this study, we extend the protection motivation theory by conceptualizing and measuring the risky IT behaviors of individuals and investigating how user, device, and usage characteristics along with the traditional protection motivation factors, influence individuals’ protective and risky IT behaviors. We collected data using an online survey. The results of our study show that individuals tend to engage in different levels of protective and risky IT behaviors on different types of devices. We also found that certain individual characteristics as well as the variety of applications that individuals use on their computing devices, influence their protective and risky IT behaviors.

In der Broschüre wird eine empfohlene Mindestausstattung der mobilen Endgeräte für Lehrkräfte beschrieben. Diese Broschüre soll die Schulträger bei der Umsetzung der »Verordnung des Sächsischen Staatsministeriums für Kultus über Zuweisungen zur Ausstattung der Lehrkräfte mit mobilen Endgeräten zum dienstlichen Gebrauch« (LehrEndFöVO) unterstützen. Redaktionsschluss: 10.02.2021

L'objectif de cette thèse est de contribuer à l'élaboration d'une méthode de test de systèmes mobiles. L'approche développée est fondée sur la description de tests à l'aide de scénarios et leurs vérifications sur une trace d'exécution. Un scénario modélise le comportement et les interactions que l'on souhaite observer entre un ensemble de nœuds. Les caractéristiques des systèmes mobiles nous ont conduit à représenter un scénario sous deux points de vue différents et complémentaires. Un premier représente des événements de communications entre les nœuds et un second représente la topologie des liens entre ces nœuds. Notre approche est décomposée en deux étapes : une étape de spécification des cas de tests à l'aide de scénarios et une étape de vérification de ces scénarios sur des traces d'exécutions. La première consiste à spécifier à l'aide du langage dédié TERMOS les cas de test de l'application mobile à vérifier. Ce langage TERMOS a été mis en œuvre au sein de l'atelier UML Papyrus. À partir des scénarios décrits de manière graphique, nous générons pour chacun d'eux un automate ainsi qu'une séquence de topologie que nous utilisons dans l'étape suivante. La deuxième étape consiste à vérifier chaque scénario sur des traces d'exécutions provenant de l'application à tester. Pour cela un premier outil recherche les occurrences de la séquence de topologie du scénario dans la trace d'exécution. Pour chacune d'entre elles, l'automate est exécuté et conclut à un verdict. L'analyse de l'ensemble des verdicts d'un scénario permet de détecter les fautes présentes dans le système. / The main objective of this thesis is to contribute to elaborating a mobile system test method. The proposed approach is based on test definition using scenarios and their verification on an execution trace. A scenario modelizes the behavior and the interactions we want to achieve on a set of nodes. Considering the characteristics of mobile systems we represented scenarios from two different but complementary points of view. The first represents communication events between nodes and the second represents the link topology between the nodes. Our approach is composed of two steps : a first step to specify the test cases by using scenarios and a second step to verify these scenarios on execution flows. The first step consists in using the dedicated TERMOS language in order to specify the test cases of the mobile application. The TERMOS language has been developed in the UML Papyrus workshop. Based on the graphically defined scenarios, we generate an automaton for each one of them, as well as a sequence of topologies which we will be using in the next step. The second step consists in verifying each scenario by using execution traces from the application to be tested. Therefore a first tool detects scenario topology sequences in the execution flow. For each one of them the automaton is executed and comes out with a verdict. The analysis of all the verdicts of a scenario allows the detection of faults in the system.

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<p>Next-generation (Next-Gen) mobile applications, Extended Reality (XR), which encompasses Virtual/Augmented/Mixed Reality (VR/AR/MR), promise to revolutionize how people interact with technology and the world, ushering in a new era of immersive experiences. However, the hardware capacity of mobile devices will not grow proportionally with the escalating resource demands of the mobile apps due to their battery constraint. To bridge the gap, edge computing has emerged as a promising approach. It is further boosted by emerging 5G cellular networks, which promise low latency and high bandwidth. However, realizing the full potential of edge computing faces several fundamental challenges.</p> <p><br></p> <p>In this thesis, we first discuss a set of fundamental design challenges in supporting Next-Gen mobile applications via edge computing. These challenges extend across the three key system components involved — mobile clients, edge servers, and cellular networks. We then present how we address several of these challenges, including (1) how to coordinate mobile clients and edge servers to achieve stringent QoE requirements for Next-Gen apps; (2) how to optimize energy consumption of running Next-Gen apps on mobile devices to ensure long-lasting user experience; and (3) how to model and generate control-plane traffic of cellular networks to enable innovation on mobile network architectural design to support Next-Gen apps not only over 4G but also over 5G and beyond.</p> <p><br></p> <p>First, we present how to optimize the latency in edge-assisted XR system via the mobile-client and edge-server co-design. Specifically, we exploit key insights about frame similarity in VR to build the first multiplayer edge-assisted VR design, Coterie. We demonstrate that compared with the prior work on single-player VR, Coterie reduces the per-player network load by 10.6X−25.7X, and can easily support 4 players for high-quality VR apps on Pixel 2 over 802.11ac running at 60 FPS and under 16ms responsiveness without exhausting the finite wireless bandwidth.</p> <p><br></p> <p>Second, we focus on the energy perspective of running Next-Gen apps on mobile devices. We study a major limitation of a classic and de facto app energy management technique, reactive energy-aware app adaptation, which was first proposed two decades ago. We propose, design, and validate a new solution, the first proactive energy-aware app adaptation, that effectively tackles the limitation and achieves higher app QoE while meeting a given energy drain target. Compared with traditional approaches, our proactive solution improves the QoE by 44.8% (Pixel 2) and 19.2% (Moto Z3) under low power budget.</p> <p><br></p> <p>Finally, we delve into the third system component, cellular networks. To facilitate innovation in mobile network architecture to better support Next-Gen apps, we characterize and model the control-plane traffic of cellular networks, which has been mostly overlooked by prior work. To model the control-plane traffic, we first prove that traditional probability distributions that have been widely used for modeling Internet traffic (e.g., Poisson, Pareto, and Weibull) cannot model the control-plane traffic due to the much higher burstiness and longer tails in the cumulative distributions of the control-plane traffic. We then propose a two-level state-machine-based traffic model based on the Semi-Markov model. We finally validate that the synthesized traces by using our model achieve small differences compared with the real traces, i.e., within 1.7%, 4.9% and 0.8%, for phones, connected cars, and tablets, respectively. We also show that our model can be easily adjusted from LTE to 5G, enabling further research on control-plane design and optimization for 4G/5G and beyond.</p>

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M. Tech. (Department of Information and Communication Technology, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Mobile devices are rapidly becoming a key computing platform, transforming how people access business and personal information. Accessing business and personal data using mobile devices requires authentication that is secure. The world is rapidly becoming connected and all users of mobile devices need to be clear regarding individual data security. As a result, biometrics for mobile devices has come into existence. Biometric technology can be applied on mobile devices to improve the trustworthiness of wireless services. Furthermore, it is of great importance and necessary to start paying attention to and investing in mobile biometric technologies, as they are quickly turning into tools of choice for productivity. In the literature review, it shows that few studies measured the acceptance of biometric authentication technology on mobile devices. This study seeks to find out the perceptions as to the acceptance of biometric authentication technology on mobile devices. TAM2 was used as the foundation for generating the hypothesis and developing the conceptual framework for this study. This quantitative study used a survey-based questionnaire to collect data from 305 participants. The simple random sampling technique was used to select participants for this study. The response rate was 98% of the expected population, which was a total of 302 valid responses. A descriptive analysis was deployed to provide a description of respondents’ demographic characteristics. SPSS was used to compute the multiple regressions in order to evaluate the research hypotheses. The findings of this study revealed that perceived humanness, perceived interactivity, perceived social presence, perceived ease of use and subjective social norm, and perceived usefulness and trust are important determinants of customers’ intention to accept and use mobile biometric devices. It was found that reliability is a good predictor of trust. On the other hand privacy, identity theft and combining data are also important determinants of trust. This work can be used to strengthen biometric authentication technology in-cooperation with mobile devices for simplicity of use. Since most mobile devices are used for personal and business information, further research on the acceptance of biometric authentication technology on mobile devices is needed.