In this thesis, a framework for Quality of Service provisioning in next generation wireless access networks is proposed. The framework aims at providing a differentiated service treatment to real-time (delay-sensitive) and non-real-time (delay-tolerant) multimedia traffic flows at the link layer. Novel techniques such as bandwidth compaction, channel reservation, and channel degradation are proposed. Using these techniques, we develop a call admission control algorithm and a call control block as part of the QoS framework. The performance of the framework is captured through analytical modeling and simulation experiments. By analytical modeling, the average carried traffic and the worst case buffer requirements for real-time and non-real-time calls are estimated. Simulation results show a 21% improvement in call admission probability of real-time calls, and a 17% improvement for non-real-time calls, when bandwidth compaction is employed. The channel reservation technique shows a 12% improvement in call admission probability in comparison with another proposed scheme in the literature.

<p>In the last decade, people have been surrounded by mobile devices such as smartphones, smartwatches, laptops, smart TVs, tablets, and IoT devices. As sensitive personal information such as photos, messages, contact information, schedules, and bank accounts are all stored on mobile devices today, the security and protection of such personal information are becoming more and more important. Today’s mobile devices are equipped with a variety of embedded sensors such as accelerometer, gyroscope, magnetometer, camera, GPS sensor, acoustic sensors, etc. that produce raw data on location, motion, and the environment around us. Based on these sensor data, we propose novel in-air signature authentication technologies on both smartphone and smartwatch in this dissertation. In-air signature authentication, as an essential behavioral biometric trait, has been adopted for identity verification and user authorization, as well as the development of deep neural networks, has vastly facilitated this field. This dissertation examines two challenging problems. One problem is how to deploy machine learning techniques to authenticate user in-air signatures in more convenient, intuitive, and secure ways by using smartphone and smartwatch in daily settings. Another problem is how to deal with the limited computational resources on today’s mobile devices which restrict to use machine learning models due to the substantial computational costs introduced by millions of parameters. </p> <p>To address the two above problems separately, we conduct the following research works. 1) The first work AirSign leverages both in-built acoustic and motion sensors on today’s smartphone for user authentication by signing signatures in the air without requiring any special hardware. This system actively transmits inaudible acoustic signals from the earpiece speaker, receives echoes back through both in-built microphones to “illuminate” signature and hand geometry, and authenticates users according to the unique features extracted from echoes and motion sensors. 2) The second work DeepWatchSign leverages in-built motion sensors on today’s smartwatch for user in-air signature authentication. The system adopts LSTM-AutoEncoder to generate negative signature data automatically from the enrolled signatures and authenticates each user by the deep neural network model. 3) We close this dissertation with an l0-based sparse group lasso approach called MobilePrune which can compress the deep learning models for both desktop and mobile platforms. This approach adopts group lasso penalty to enforce sparsity at the group level to benefit General Matrix Multiply (GEMM) and optimize the l0 norm in an exact manner. We observe the substantial reduction of compression ratio and computational costs for deep learning models. This method also achieves less response delay and battery consumption on mobile devices.</p>

Thesis (MComm)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The consumerisation of mobile technology is driving the mobile revolution and enterprises are forced to incorporate mobile solutions into their business processes in order to remain competitive. While there are many benefits relating to the investment in and use of mobile technology, significant risks are also being introduced into the business. The fast pace of technological innovation and the rate of adoption of mobile technology by employees has, however, created an environment where enterprises are deploying mobile solutions on an ad hoc basis. Enterprises are only addressing the risks as they are occurring and resulting in losses. The key contributing factor to this lack of governance and management is the fact that those charged with governance do not understand the underlying mobile technology components. The purpose of this research is to improve the understanding of the underlying components of mobile technology. The research further proposes to use this understanding to identify the significant risks related to mobile technology and to formulate appropriate internal controls to address these risks. The findings of the research identified the following underlying components of mobile technology: mobile devices; mobile infrastructure, data delivery mechanisms and enabling technologies; and mobile applications. Based on an understanding of the components and subcategories of mobile technology, a control framework was used to identify the significant risks related to each component and subcategory. The significant risks identified included both risks to the users (including interoperability, user experience, connectivity and IT support) as well as risks to the enterprise’s strategies (including continuity, security, cost and data ownership). The research concludes by formulating internal controls that the enterprise can implement to mitigate the significant risks. This resulted in two matrixes that serve as quick-reference guides to enterprises in the identification of significant risks at an enterprise specific mobile technology component level, as well as the relevant internal controls to consider. The matrixes also assist enterprises in determining the best mobile solutions to deploy in their business, given their strategies, risk evaluation and control environment. / AFRIKAANSE OPSOMMING: Die mobiele revolusie word deur die verbruiker van mobiele tegnologie aangedryf en, ten einde kompeterend te bly, word ondernemings gedwing om mobiele tegnologie in hul besigheidsprosesse te implementeer. Terwyl daar baie voordele verbonde is aan die investering in en gebruik van mobiele tegnologie, word die besigheid egter ook blootgestel aan wesenlike risiko’s. Die vinnige tempo waarteen mobiele tegnologie ontwikkel en deur werknemers aangeneem word, het egter ʼn omgewing geskep waarin ondernemings mobiele tegnologie op ʼn ad hoc basis ontplooi. Besighede spreek eers die risiko’s aan nadat dit reeds voorgekom het en verliese as gevolg gehad het. Die hoof bydraende faktor tot die tekort aan beheer en bestuur van mobiele tegnologie is die feit dat diegene verantwoordelik vir beheer, nie onderliggend mobiele tegnologie komponente verstaan nie. Die doel van hierdie navorsing is om die begrip van die onderliggende komponente van mobiele tegnologie te verbeter. Die navorsing poog verder om die wesenlike risiko’s verbonde aan mobiele tegnologie te identifiseer en om toepaslike interne beheermaatreëls te formuleer wat die risiko’s sal aanspreek. Die bevindinge van die navorsing het die volgende onderliggende komponente van mobiele tegnologie geïdentifiseer: mobiele toestelle; mobiele infrastruktuur, data afleweringsmeganismes, en bemagtigende tegnologieë; en mobiele toepassings. Gebaseer op ʼn begrip van die komponente en subkategorieë van mobiele tegnologie, is ʼn kontrole raamwerk gebruik om die wesenlike risiko’s verbonde aan elke komponent en subkategorie van die tegnologie, te identifiseer. Die wesenlike risiko’s sluit beide risiko’s vir die gebruiker (insluitend kontinuïteit, gebruikerservaring, konnektiwiteit en IT ondersteuning) sowel as risiko’s vir die onderneming se strategieë (insluitend kontinuïteit, sekuriteit, koste en data eienaarskap) in. Die navorsing sluit af met die formulering van die beheermaatreëls wat geïmplementeer kan word om die wesenlike risiko’s aan te spreek. Dit het gelei tot twee tabelle wat as vinnige verwysingsraamwerke deur ondernemings gebruik kan word in die identifisering van wesenlike risiko’s op ʼn onderneming-spesifieke tegnologie komponentvlak asook die oorweging van relevante interne beheermaatreëls. Die tabelle help ondernemings ook om die beste mobiele tegnologie vir hul besigheid te implementeer, gebaseer op hul strategie, risiko evaluering en beheeromgewing.

M.Tech (Department of Information technology, Faculty of Applied and Computer Science), Vaal University of Technology. / The advancement of technology, particularly in the area of mobile computing, revolutionizes the way business is done in many industries such as the education sector, government sector, financial institutions, retail sector and the way people conduct their daily activities. The current technology provides influential tools for organisations and can significantly influence their operation, structure and approach. The development of mobile computing has created a new innovation for various industries by increasing the availability, frequency and speed of communication between the organisations and the individuals. However, users’ perceptions can play an important role towards the adoption of these new developments. The overriding purpose of this study was to investigate the users’ perceptions on the security of mobile computing in South Africa for adoption of e-applications. The literature review was concentrated on the process of progressive development occurring during the study. To accomplish that goal it became necessary to reach some essential objectives i.e. investigating the users’ perceptions models in literature. For the purpose of the study, it was important to propose a research framework for users’ perceptions on the security of mobile computing with the potential for the adoption of e-applications in South Africa. The research evaluated the proposed framework to establish if there is any relationship between the e-application adoption factors. Furthermore, the hypotheses were tested to determine which factors would influence the adoption of e-applications in South Africa. Technology Adoption Model 2 (TAM2) and Diffusion of Innovation (DOI) provide the theoretical basis for explaining how users perceive e-application services that they access and operate through mobile computing. To achieve that, a quantitative study was conducted with South African residents, with respect to mobile security perceptions; 476 valid questionnaires were received from the participants who were selected non-randomly. Questionnaires were developed from the proposed research framework derived from DOI and TAM2 and the items were adopted from other prior technology adoption studies. Through the use of the survey instrument developed for this study, data were collected in order to address the importance of this study based on the problem statement posed in the first chapter of this dissertation. The valid questionnaires were analysed by using the Statistical Package for the Social Sciences (SPSS), Version 24.0. Reliability analysis, principal component analysis, correlations and multiple linear regression tests were conducted. Among other things this study made sure that ethical considerations are adhered to. The findings revealed positive relationships between perceived usefulness of security mechanisms, perceived ease of use of security mechanisms, subjective norm on security mechanisms, relative advantage of security mechanisms, compatibility of security mechanisms, complexity of security mechanisms, aesthetics of security mechanisms interface and intention to adopt e-applications. Furthermore, subjective norm on security mechanisms was strongly correlated to intention to adopt e-applications, complexity of security mechanisms strongly correlated to perceived usefulness of security mechanisms, relative advantage of security mechanisms and aesthetic of security mechanisms interface strongly correlated to perceived usefulness of security mechanisms. In addition, subjective norm of security mechanisms strongly influence intention to adopt eapplications in South Africa. Also, aesthetics of security mechanisms interface strongly influence both perceived usefulness of security mechanisms and perceived ease of use of security mechanisms. The reason behind it may be interpreted as users nowadays seeing the beauty as the platform to attract and encourage them to use e-applications. Finally, the proposed model analysis and survey evaluation will enable South African organizations to make informed decisions about the use of e-applications services. These findings contribute to a road map for the education sector, government sector, financial institutions, and retail sector as well as to encourage their customers or clients to adopt e-applications.

Context: This protocol is as a supplementary document to our review paper that investigates security-related challenges and solutions that have occurred during the past decade (from January 2003 to December 2014). Objectives: The objective of this systematic review is to identify security-related challenges, security goals, and defenses in ubiquitous computing by answering to three main research questions. First, demographic data and trends will be given by analyzing where, when and by whom the research has been carried out. Second, we will identify security goals that occur in ubiquitous computing, along with attacks, vulnerabilities and threats that have motivated the research. Finally, we will examine the differences in addressing security in ubiquitous computing with those in traditional distributed systems. Method: In order to provide an overview of security-related challenges, goals and solutions proposed in the literature, we will use a systematic literature review (SLR). This protocol describes the steps which are to be taken in order to identify papers relevant to the objective of our review. The first phase of the method includes planning, in which we define the scope of our review by identifying the main research questions, search procedure, as well as inclusion and exclusion criteria. Data extracted from the relevant papers are to be used in the second phase of the method, data synthesis, to answer our research questions. The review will end by reporting on the results. Results and conclusions: The expected results of the review should provide an overview of attacks, vulnerabilities and threats that occur in ubiquitous computing and that have motivated the research in the last decade. Moreover, the review will indicate which security goals are gaining on their significance in the era of ubiquitous computing and provide a categorization of the security-related countermeasures, mechanisms and techniques found in the literature. (authors' abstract)

The Transmission Line Matrix (TLM) method is an existing and established mathematical method for conducting computational electromagnetic (CEM) simulations. TLM models Maxwell s equations by discretising the contiguous nature of an environment and its contents into individual small-scale elements and it is a computationally intensive process. This thesis focusses on parallel processing optimisations to the TLM method when considering the opposing ends of the contemporary computing hardware spectrum, namely large-scale computing systems versus small-scale mobile computing devices. Theoretical aspects covered in this thesis are: The historical development and derivation of the TLM method. A discrete random variable (DRV) for rain-drop diameter,allowing generation of a rain-field with raindrops adhering to a Gaussian size distribution, as a case study for a 3-D TLM implementation. Investigations into parallel computing strategies for accelerating TLM on large and small-scale computing platforms. Implementation aspects covered in this thesis are: A script for modelling rain-fields using free-to-use modelling software. The first known implementation of 2-D TLM on mobile computing devices. A 3-D TLM implementation designed for simulating the effects of rain-fields on extremely high frequency (EHF) band signals. By optimising both TLM solver implementations for their respective platforms, new opportunities present themselves. Rain-field simulations containing individual rain-drop geometry can be simulated, which was previously impractical due to the lengthy computation times required. Also, computationally time-intensive methods such as TLM were previously impractical on mobile computing devices. Contemporary hardware features on these devices now provide the opportunity for CEM simulations at speeds that are acceptable to end users, as well as providing a new avenue for educating relevant user cohorts via dynamic presentations of EM phenomena.

Le développement d'applications sur réseaux mobiles ad hoc présente des contraintes liées à la mobilité des terminaux, à la nature décentralisée des manets, et aux ressources limitées, et nécessite donc la mise en place d'une algorithmique nouvelle. Cette thèse propose des algorithmes permettant la mise en place d'un système de partage de données sur manet : - un algorithme de création de grappes de terminaux mobiles stables dans le temps, qui présente l'avantage de ne pas utiliser de ressources réseaux (utilisation informations inter-couches). - un algorithme de réplication de données pro-actif, qui maintien un nombre de répliques k proportionnel au nombre de terminaux présents et les place sur les terminaux les plus susceptibles de les utiliser. Cela augmente la disponibilité et la fiabilité du service. - un algorithme de gestion de cache, qui maintient le nombre de répliques au minimum permettant un usage efficace du réseau et offrant une bonne disponibilité. D'une part, il élimine les données utilisées le moins récemment et dont le nombre de répliques est supérieur à k. D'autre part, il diminue la charge réseau en éliminant les répliques de données non utilisées par leur hôte.

La gestion des perturbations des flux de production (problèmes d'approvisionnement, défaillances des ressources, problèmes de qualité...) est une problèmatique importante lors du pilotage de systèmes de production. Les architectures de pilotage existantes offrent peu de concepts à la fois spécifiquement dédiés et suffisament génériques pour permettre de gérer une variété de types de perturbations. Dans ce contexte, l'immunité biologique représente un système naturellement capable de réagir et de s'adapter aux menaces qui guettent l'organisme hôte. Nous nous inspirons des principes de fonctionnement de ce système pour identifier les principales caractéritiques d'une architecture distribuée de pilotage. Cette architecture met en oeuvre des fonctions suffisamment génériques et spécifiquement dédiées à la gestion des perturbations, telles que les fonctions de détection, d'identification et de réaction aux perturbations. Cette architecture est réalisée grâce à la technologie des systèmes multi-agents, et permet en plus de capitaliser les connaissances sur les perturbations en vue d'une réalisation future

Mobile applications can benefit from increased awareness of the device's context. Unfortunately, existing solutions for inferring context require special purpose sensors or beacons on the mobile devices or in the physical environment. This requirement significantly limits the deployment of these solutions. In this thesis, I argue that mobile devices can infer a substantial amount of their context by leveraging their existing wireless interfaces to monitor ambient radio sources, such as GSM cell towers or WiFi access points. I focus on two important problems in context-aware computing: localization of mobile devices and detecting proximity between mobile devices for authentication purposes. Specifically, I present an accurate localization system based on fingerprinting of GSM signals. I show that the key to more accurate GSM localization is the use of wide signal strength fingerprints that include readings from a large number of base stations. Next, I present a method that addresses the key drawback of fingerprint-based localization systems - the need to collect extensive measurements to train the system in every target environment. Finally, I show how radio environment sensing can be used to secure the communication of devices that come within close proximity. Removing the need for additional hardware on the mobile devices and in the physical environment renders the approach that I present amenable for widespread deployment.

Our increasing reliance on mobile devices has given rise to a new class of software applications (i.e., mobile apps). Tens of thousands of developers have developed hundreds of thousands of mobile apps that are available across multiple platforms. These apps are used by millions of people around the world every day. However, most software engineering research has been performed on large desktop or server applications. We believe that research efforts must begin to examine mobile apps. Mobile apps are rapidly growing, yet they differ from traditionally-studied desktop/server applications. In this thesis, we examine such apps by performing three quantitative studies. First, we study differences in the size of the code bases and development teams of desktop/server applications and mobile apps. We then study differences in the code, dependency and churn properties of mobile apps from two different mobile platforms. Finally, we study the impact of size, coupling, cohesion and code reuse on the quality of mobile apps. Some of the most notable findings are that mobile apps are much smaller than traditionally-studied desktop/server applications and that most mobile apps tend to be developed by only one or two developers. Mobile app developers tend to rely heavily on functionality provided by the underlying mobile platform through platform-specific APIs. We find that Android app developers tend to rely on the Android platform more than BlackBerry app developers rely on the BlackBerry platform. We also find that defects in Android apps tend to be concentrated in a small number of files and that files that depend on the Android platform tend to have more defects. Our results indicate that major differences exist between mobile apps and traditionally-studied desktop/server applications. However, the mobile apps of two different mobile platforms also differ. Further, our results suggest that mobile app developers should avoid excessive platform dependencies and focus their testing efforts on source code files that rely heavily on the underlying mobile platform. Given the widespread use of mobile apps and the lack of research surrounding these apps, we believe that our results will have significant impact on software engineering research. / Thesis (Master, Computing) -- Queen's University, 2013-01-24 10:15:56.086