As humans we find communicating natural and compelling. Over the centuries we have created many innovations which enable and improve communication between people; during the past decade mobile phone networks have brought about a technological revolution in this area. Never before have people been so connected to one another. Today we have the ability to communicate with almost anyone, anytime, anywhere. Our increased connectivity and reachability also leads to new issues and challenges that we need to deal with. When we phone someone we expect an instant connection, and when this does not occur it can be frustrating. On the other hand it is equally disruptive to receive a call when one is busy with an important task or in a situation where communication is inappropriate. Social protocol dictates that we try to minimize such situations for the benefit of others nearby and for ourselves. This management of communications is a constant and difficult task. Using presence – which signals a person’s availability and willingness to communicate – is a solution to this problem. Such information can benefit communication partners by increasing the likelihood of a successful connection and decreasing disruptions. This research addresses the problem of staying connected while keeping control over mobile communications. It adopts a design-science research paradigm, with the primary research artifact being a model for privacy-aware presence management in mobile communications. As part of the model development knowledge contributions are made in several ways. Existing knowledge about the problem area is extended through a quantitative analysis of mobile communications management. This analysis uses a novel survey, collecting useful empirical data for future research. This includes how people currently manage their communications and what features they expect from a potential “call management” system. The examination and use of presence standards, as a foundation for the model, provides a comparison of the main presence technologies available today. A focus on privacy features identifies several shortcomings in standards which, if addressed, can help to improve and make these standards more complete. The model stresses the privacy of potentially sensitive presence information. A unique perspective based on social relationship theories is adopted. The use of relationship groups not only makes logical sense but also assists in the management of presence information and extends existing standards. Finally, the evaluation of the model demonstrates the feasibility of a practical implementation as well the ability to extend the model in next generation mobile networks. Thus the model presents a solid foundation for the development of future services. In these ways the proposed model contributes positively towards balancing efficient mobile communications with the need for privacy-awareness.

University of Macau / Faculty of Science and Technology / Department of Computer and Information Science

MCom / Department of Business Management / Mobile technology is progressively being used to support students’ learning, extending learning and educator-student contact beyond class hours. Mobile technology has been identified as a potential solution to the problem of scarcity of computers to access online learning materials in higher education institutions. The University of Venda distributed tablet personal computers to students so that they could use them for facilitating and enhancing their studies. However, the provision of tablet PCs to students may not be a panacea for quality learning, especially to a population that is not familiar with latest information technologies. The aim of the study was to investigate the use of digital mobile devices (tablet personal computers and smartphones) for enhancing teaching and learning at the University of Venda. The research questions focused on determining the current level of use of mobile devices, how they could be used effectively for teaching and learning; and the perceptions of students and lecturers on mobile devices as tools for teaching and learning. Case study research design was considered most suitable for this study as it involves collecting and reporting descriptive information about a specific environment. Mixed methods approach was applied with data being solicited from a convenient sample of 370 students, 8 lecturers and 1 IT technician at the University. Semi-structured questionnaires were distributed to students. The results of the study indicated that many students are active and spending much time on the different internet activities. The study also found that students prefer mobile learning and spend much time on the internet surfing information. Lecturers found it easy to communicate with the students via emails and social media platforms where they send study materials. Students use their smartphones and tablet PCs to download learning materials. However, many lecturers and students are not making use of the Learning Management System, the Blackboard due to lack of training. The results of the study are to be used to explicate, forecast, and advance the integration of the digital mobile devices for promoting learning and teaching accomplishments and standard competencies at the University of Venda. Recommendations were made on how students and lecturers can effectively use digital mobile devices for teaching and learning.

In today’s work place where corporations allow employees to use their own smart phones to access their company’s network and sensitive data, it is essential to ensure the security of said data. When an employee smart phone is compromised, companies will rely on the remote wipe command that attempts to remove sensitive data. In this thesis, we analyze the effectiveness of remote wipe commands on the Apple iPhone and Android model devices and demonstrate how data can be recovered following a remote wipe procedure. We conduct two experiments on each device to verify whether remote wipe is a viable defense mechanism or not. Furthermore, we touch on the subject of mobile forensics used by law enforcement and review methods and techniques used to recover data for use as evidence in criminal cases.

Mobile computation offloading (MCO) can alleviate the hardware limitations of mobile devices by migrating heavy computational tasks from mobile devices to more powerful cloud servers. This can lead to better performance and energy savings for the mobile devices. This thesis considers MCO over stochastic wireless channels when task completion times are subject to hard deadline constraints. Hard deadlines, however, are difficult to meet in conventional computation offloading due to the randomness caused by the wireless channels. In the proposed offloading policies, concurrent local execution (CLE) is used to guarantee task execution time constraints. By sometimes allowing simultaneous local and remote execution, CLE ensures that job deadlines are always satisfied in the face of any unexpected wireless channel conditions. The thesis introduces online optimal algorithms that reduce the remote and local execution overlap so that energy wastage is minimized. Markov processes are used to model the communication channels. MCO is addressed for three different job offloading schemes: continuous, multi-part, and preemptive. In the case of continuous offloading, referred to as 1-Part offloading, the mobile device will upload the entire job in one piece without interruption, when the scheduler decides to do so. In multi-part computation offloading, the job is partitioned into a known number (K) of parts, and each part is uploaded separately. In this offloading mechanism, which is referred to as K-Part Offloading, the upload initiation times of each part must be determined dynamically during runtime, and there may be waiting time periods between consecutive upload parts. Preemptive offloading is a generalization of K-Part Offloading where the number of task upload parts is unknown. In this scheme, a decision to either continue offloading or to temporarily interrupt the offload is made at the start of each time slot. Compared to the conventional contiguous computation offloading, interrupted offloading mechanisms (i.e., K-Part and preemptive offloading) allow the system to adapt when channel conditions change and therefore may result in lower mobile device energy consumption. This energy reduction will be obtained at the expense of having higher computational complexity. In this thesis, for each offloading scheme, an online computation offloading algorithm is introduced by constructing a time-dilated absorbing Markov chain (TDAMC) and applying dynamic programming (DP). These algorithms are shown to be energy-optimal while ensuring that the hard task deadline constraints are always satisfied. The optimality of these algorithms is proved using Markovian decision process stopping theory. Since the computational complexity of the proposed online algorithms, especially in the case of preemptive offloading, can be significant, three simpler and computationally efficient approximation methods are introduced: Markovian Compression (MC), Time Compression (TC), and Preemption Using Continuous Offloading (Preemption-CO). MC and TC reduce the state space of the offloading Markovian process by using a novel notion of geometric similarity or by running an optimal online offloading algorithm in periodic time steps. In Preemption-CO, while a task is offloaded preemptively, the offloading decision at every time-slot is based on non-preemptive calculations. These methods are used alone or in combination to construct practical offloading algorithms. A variety of results are presented that show the tradeoffs between complexity and mobile energy-saving performance for the different algorithms. / Thesis / Doctor of Philosophy (PhD)

In this thesis, we compare the energy efficiency of various strategies of mobile computation offloading over stochastic transmission channels where the task completion time is subject to a latency constraint. In the proposed methods, finite-state Markov chains are used to model the wireless channels between the mobile devices and the remote servers. We analyze the mechanisms of efficient mobile computation offloading under both soft and hard latency constraints. For the case of soft latency constraint, the task completion could miss the deadline below a specified probability threshold. On the other hand, under a hard deadline constraint, the task execution result must be available at the mobile device before the deadline. In order to make sure the task completes before the hard deadline, the hard deadline constraint approach requires concurrent execution in both local and cloud in specific circumstances. The closed-form solutions are often obtained using the broad Markov processes. The GE (Gilbert-Elliott) model is a more efficient method for demonstrating how the Markov chain’s structure can be used to compute the best offload initiation (Hekmati et al., 2019a).The effectiveness of the algorithms is studied under various deadline constraints and offloading methods. In this thesis, six algorithms are assessed in various scenarios. 1) Single user optimal (Zhang et al., 2013), 2) LARAC (Lagrangian Relaxation Based Aggregated Cost) (Zhang et al., 2014), 3) OnOpt (Online Optimal) algorithm (Hekmati et al., 2019a), 4) Water-Filling With Equilibrium (WF-Equ), 5) Water-Filling With Exponentiation (WFExp) (Teymoori et al., 2021), 6) MultiOPT (Multi-Decision Online Optimal). The experiment demonstrates that the studied algorithms perform dramatically different in the same setting. The various types of deadline restrictions also affect how efficiently the algorithms use energy. The experiment also highlights the trade-off between computational complexities and mobile energy savings (Teymoori et al., 2021).

I detta projekt studerade vi digitala påminnelser för ungdomar. En serie fältstudier utfördes vilka visade att digitala påminnelser var väldigt användbara för denna demografiska grupp. Vidare, en digital påminnelse-prototyp, RemindMe, föreslogs och implementerades, och dess användbarhet fastställdes i avslutande användartest. / n this project digital reminders for youths were studied. A series of field studies were conducted where digital reminders were shown to be highly useful for this demographic. Also, a digital reminder prototype, RemindMe, was proposed and implemented, and its usefulness shown through concluding field tests.

Yes / Purpose – This study aims to examine the impact of mobile interactivity dimensions (active control, personalization, ubiquitous connectivity, connectedness, responsiveness, and synchronicity) on customer engagement. Design/methodology/approach – A quantitative field survey study was conducted to collect the required data from actual users of mobile shopping in three countries: Jordan, the United Kingdom (UK) and Saudi Arabia. Findings – The results are based on structural equation modelling and support the impact of five dimensions of mobile interactivity: active control, personalization, ubiquitous connectivity, responsiveness, and synchronicity. Research limitations/implications – This study only considered the shopping activities conducted by mobile channels, while other channels (e.g. online channels, traditional channels, and social media shopping channels) are not considered. Furthermore, the current model does not consider the impact of personal factors (e.g. technology readiness, self-efficacy, user experience). The results of the current study present a foundation that can guide marketers and practitioners in the area of mobile shopping. Originality/value – This study enriches the current understanding of the impact of mobile interactivity on mobile shopping, as well as how mobile interactivity can enhance the level of customer engagement.

This thesis addresses the paucity of research on network mobility with a taxonomy and a quantitative comparison on a real test bed of existing and forthcoming network mobility solutions. Broadly, network mobility solutions can be divided into two broad categories, intra-domain and inter-domain solutions. The two are distinct enough to warrant separate solutions. Network mobility solutions can also be divided into four catogories according to their implementation, (i) Mobile IP-based solutions, (ii) Mobile IP Mobile Routing, (iii) intra-domain routing protocols, and (iv) Mobile IP Foreign Agent-based solutions. This latter division by implementation serves as a useful starting point for a discussion and study of these protocols. The qualitative and quantitive comparisons presented here yield two "winning" solutions, Mobile IP with Network Address Translation (NAT) and Mobile IP Mobile Routing, both based on Mobile IP, the draft standard for Internet mobility. The two were chosen because they are the only solutions fit for production networks, not necessarily because they are the best performing solutions. Indeed, nearly all of the other solutions are promising alternatives and some, such as mobile ad hoc network (MANET) routing protocols and the solutions based on the next generation Internet (IPv6) version of Mobile IP, are particularly so. One of the solutions uses a novel extension for Mobile IP, the Multiple Home Address extension, developed and specified in this thesis, that turns a Mobile IP mobile node into a mobile router able to support dynamically sizing mobile networks while using the existing Mobile IP infrastructure. / Master of Science

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