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)

Les applications contextuelles doivent gérer un flux contenu de contexte selon une logique approprié. Les travaux de recherche en contextualisation se limitent à proposer des plateformes de développement proposant des mécanismes d’adaptation prédéfinie. Cette thèse se propose d’étende l’état de l’art en proposant des nouveaux concepts formant la fondation pour la création d’application contextuelles en adoptant des principes de l’ingénierie logicielle et une décomposition fonctionnelle. Aussi, cela permet l’intégration de comportements contextualisés à des applications non initialement conçus pour cela. La thèse propose une autre manière centrée-contexte permettant de séparer la représentation du contexte de son interprétation, offrant encore plus de flexibilité à la gestion de contexte. Les propositions sont analysées aux lumières d’étude de cas et de simulations. Le résultat de la thèse est l’introduction de nouvelle approche de création d’applications contextuelles qui met en avant le développeur mais aussi l’utilisateur / Context-aware applications must manage a continuous stream of context according to dedicated business logic. Research was limited on proposing frameworks and platforms that have predefined behavior toward applications. This thesis attempts to extend background works by proposing new concepts serving as foundation for a flexible approach for building context-aware applications. The thesis examines the state of the art of context-aware computing, then adopts well-established software design principles and a functional decomposition for designing a reference model for context management enabling seamless integration of context-awareness into applications. Also, the thesis studies the use of context in common applications and proposes a context-centric modeling approach which allows the creation of a graph-based representation where entities are connected to each other through links representing context. Furthermore, the context graph decouples the presentation and the semantics of context, leaving each application to manage the appropriate semantic for their context data. Case studies are conducted for the evaluation of the proposed system in terms of its support for the creation of applications enhanced with context-awareness. A simulation study is performed to analyze the performance properties of the proposed system. The result of this thesis is the introduction of a novel approach for supporting the creation of context-aware applications that supports the integration of context-awareness to existing applications. It empowers developers as well as users to participate in the creation process, thereby reducing usability issues

Les applications Web sont l’épine dorsale des systèmes d’information modernes. L’exposition sur Internet de ces applications engendre continuellement de nouvelles formes de menaces qui peuvent mettre en péril la sécurité de l’ensemble du système d’information. Pour parer à ces menaces, il existe des solutions robustes et riches en fonctionnalités. Ces solutions se basent sur des modèles de détection des attaques bien éprouvés, avec pour chaque modèle, des avantages et des limites. Nos travaux consistent à intégrer des fonctionnalités de plusieurs modèles dans une seule solution afin d’augmenter la capacité de détection. Pour atteindre cet objectif, nous définissons dans une première contribution, une classification des menaces adaptée au contexte des applications Web. Cette classification sert aussi à résoudre certains problèmes d’ordonnancement des opérations d’analyse lors de la phase de détection des attaques. Dans une seconde contribution, nous proposons une architecture de filtrage des attaques basée sur deux modèles d’analyse. Le premier est un module d’analyse comportementale, et le second utilise l’approche d’inspection par signature. Le principal défi à soulever avec cette architecture est d’adapter le modèle d’analyse comportementale au contexte des applications Web. Nous apportons des réponses à ce défi par l’utilisation d’une approche de modélisation des comportements malicieux. Ainsi, il est possible de construire pour chaque classe d’attaque son propre modèle de comportement anormal. Pour construire ces modèles, nous utilisons des classifieurs basés sur l’apprentissage automatique supervisé. Ces classifieurs utilisent des jeux de données d’apprentissage pour apprendre les comportements déviants de chaque classe d’attaques. Ainsi, un deuxième verrou en termes de disponibilité des données d’apprentissage a été levé. En effet, dans une dernière contribution, nous avons défini et conçu une plateforme de génération automatique des données d’entrainement. Les données générées par cette plateforme sont normalisées et catégorisées pour chaque classe d’attaques. Le modèle de génération des données d’apprentissage que nous avons développé est capable d’apprendre "de ses erreurs" d’une manière continue afin de produire des ensembles de données d’apprentissage de meilleure qualité. / Web applications are the backbone of modern information systems. The Internet exposure of these applications continually generates new forms of threats that can jeopardize the security of the entire information system. To counter these threats, there are robust and feature-rich solutions. These solutions are based on well-proven attack detection models, with advantages and limitations for each model. Our work consists in integrating functionalities of several models into a single solution in order to increase the detection capacity. To achieve this objective, we define in a first contribution, a classification of the threats adapted to the context of the Web applications. This classification also serves to solve some problems of scheduling analysis operations during the detection phase of the attacks. In a second contribution, we propose an architecture of Web application firewall based on two analysis models. The first is a behavioral analysis module, and the second uses the signature inspection approach. The main challenge to be addressed with this architecture is to adapt the behavioral analysis model to the context of Web applications. We are responding to this challenge by using a modeling approach of malicious behavior. Thus, it is possible to construct for each attack class its own model of abnormal behavior. To construct these models, we use classifiers based on supervised machine learning. These classifiers use learning datasets to learn the deviant behaviors of each class of attacks. Thus, a second lock in terms of the availability of the learning data has been lifted. Indeed, in a final contribution, we defined and designed a platform for automatic generation of training datasets. The data generated by this platform is standardized and categorized for each class of attacks. The learning data generation model we have developed is able to learn "from its own errors" continuously in order to produce higher quality machine learning datasets .

Ces travaux s'inscrivent dans le contexte de la gestion de l'énergie électrique dans les applications domestiques 230V - 50Hz. Le niveau de puissance visé se situe aux environs de la centaine de watts, et les structures de conversion utilisent des interrupteurs bidirectionnels bicommandables réalisés aujourd'hui à l'aide d'associations anti-série de composants de type MOS. Malgré les améliorations apportées par certains de ces dispositifs, leur coût de fabrication reste encore élevé et limite leur plus large diffusion sur ce marché partagé avec le triac à ce jour. Nous proposons une architecture de structure bipolaire bidirectionnelle en courant et symétrique en tension appelée BipAC. Le BipAC est une structure verticale bidirectionnelle, contrôlable à la fermeture et à l'ouverture, réalisable sur substrat N (BipAC PNP) ou P (BipAC NPN). Sa faible chute de tension à l'état passant et sa commande ON/OFF avec une seule électrode de référence la rendent intéressante pour des applications spécifiques à faible niveau de courant (<1A). L'étude de la structure BipAC s'appuie sur des simulations physiques 2D effectuées à l'aide du logiciel SentaurusTM. Afin d'améliorer le gain en courant de la structure BipAC initiale, une nouvelle version du BipAC a été proposée et validée par des simulations physiques 2D (de type process et électrique). Ensuite, des masques sont conçus sous le logiciel CadenceTM. La structure initiale est réalisée sur les deux types de substrat et pour deux épaisseurs différentes de chaque type. La fonctionnalité du BipAC est validée par des caractérisations électriques. / This thesis work deals with the design of an AC switch structure for specific ac mains applications 230V - 50 Hz. The targeted power level is about a hundred watts, and the currently used converter circuits make use of bidirectional switches that are realized using anti-series connected MOS transistors. Despite the improvements in performance provided by some of these structures, their fabrication cost is still high and limits their widespread diffusion in a market shared with the triac. We propose a current and voltage bidirectional bipolar device called a BipAC. It can be realized in an N-substrate (PNP BipAC) or a P-substrate (NPN BipAC). It can be controlled both to turn-on and turn-off with respect to a single reference electrode. It exhibits a very low on-state voltage that makes it attractive for specific mains applications with low load current (< 1A rms). The study of the BipAC structure is carried-out using 2D SentaurusTM physical simulations. In order to improve the current gain of the initial BipAC structure, a new version of the BipAC structure is proposed and its operating modes validated using 2D physical simulations (both process and electrical). Masks were then designed under CadenceTM software. The initial BipAC structure is realized on N and P substrates and for two different thicknesses. The operating modes of the monolithic bidirectional BipAC switch were validated through electrical characterizations.

Secure enclave technology has during the last decade emerged as an important hardware security primitive in server computer cores, and increasingly also in chips intended for consumer devices like mobile phones and PCs. The Linux Confidential Compute Consortium has taken a leading role in defining the host APIs for enclave access (e.g. OpenEnclave APIs). Earlier solutions for security isolation in mobile phones relied on so called Trusted Execution Environments, which are similar in hardware isolation, but serve primarily OEM device security use-cases, and the environments are access controlled by remote trust roots (code signatures). This thesis examines the security requirements for enclaves, visible through APIs and SDKs. An augmented IDE / SDK interface that accounts for security, including legacy considerations present with TEEs is also proposed. This thesis also attempts to improve developer experience related to development of trusted application by providing a tight integration with IDE and an expressive way to select methods which can be carved out of an existing rust application into a seperate trusted application. Furthermore, this thesis also discusses some common pitfalls while developing code for trusted applications and attempts to mitigate several of the discussed risks. The work plan includes a background study on existing TEE and enclave SDKs, a novel SDK augmentation that accounts for the features listed above, and a prototype implementation that highlights the enclave security needs beyond mere isolated execution. An IDE plugin is also implemented, that exemplifies how software engineers (with potentially limited security knowledge) can implement a trusted application service with enclave support such that the end result (enclave code) will run without information leakage or interface security problems. / Säker enklavteknologi har under S senaste decenniet framstått som en viktig hårdvarusäkerhets primitiv i serverdatorkärnor och i allt högre grad även i chips avsedda för konsumentenheter som mobiltelefoner och datorer. Linux Confidential Compute Consortium har tagit en ledande roll i att definiera värdAPI:erna för enklavåtkomst (t.ex. OpenEnclave APIs). Tidigare lösningar för säkerhetsisolering i mobiltelefoner förlitade sig på så kallade Trusted Execution Environments, som liknar hårdvaruisolering, men som i första hand tjänar OEMenhetssäkerhetsanvändning, och miljöerna är åtkomstkontrollerade av fjärrstyrda förtroenderötter (kodsignaturer). Denna avhandling undersöker säkerhetskraven för enklaver, synliga genom API:er och SDK:er. Ett utökat IDE/SDK-gränssnitt som står för säkerhet, inklusive äldre överväganden som finns med TEE, föreslås också. Detta examensarbete försöker också förbättra utvecklarupplevelsen relaterad till utveckling av betrodda applikationer genom att tillhandahålla en tät integration med IDE och ett uttrycksfullt sätt att välja metoder som kan skäras ut ur en befintlig rostapplikation till en separat betrodd applikation. Dessutom diskuterar denna avhandling också några vanliga fallgropar samtidigt som man utvecklar kod för betrodda applikationer och försöker mildra flera av de diskuterade riskerna. Arbetsplanen inkluderar en bakgrundsstudie av befintliga TEE- och enklav-SDK:er, en ny SDK-förstärkning som står för funktionerna som anges ovan, och en prototypimplementering som belyser enklavens säkerhetsbehov utöver enbart isolerad exekvering. En IDE-plugin är också implementerad, som exemplifierar hur mjukvaruingenjörer (med potentiellt begränsad säkerhetskunskap) kan implementera en betrodd applikationstjänst med enklavstöd så att slutresultatet (enklavkoden) kommer att köras utan informationsläckage eller gränssnittssäkerhetsproblem.

The Quality of Service (QoS) routing approach is gaining an increasing interest in the Internet community due to the new emerging Internet applications such as real-time multimedia applications. These applications require better levels of quality of services than those supported by best effort networks. Therefore providing such services is crucial to many real time and multimedia applications which have strict quality of service requirements regarding bandwidth and timeliness of delivery. QoS routing is a major component in any QoS architecture and thus has been studied extensively in the literature. Scalability is considered one of the major issues in designing efficient QoS routing algorithms due to the high cost of QoS routing both in terms of computational effort and communication overhead. Localized quality of service routing is a promising approach to overcome the scalability problem of the conventional quality of service routing approach. The localized quality of service approach eliminates the communication overhead because it does not need the global network state information. The main aim of this thesis is to contribute towards the localised routing area by proposing and developing some new models and algorithms. Toward this goal we make the following major contributions. First, a scalable and efficient QoS routing algorithm based on a localised approach to QoS routing has been developed and evaluated. Second, we have developed a path selection technique that can be used with existing localized QoS routing algorithms to enhance their scalability and performance. Third, a scalable and efficient hierarchical QoS routing algorithm based on a localised approach to QoS routing has been developed and evaluated.

This thesis seeks to advance the field of microrobotics by leveraging Bayesian principles and computational tools to design system parameters for information gain and microrobot propulsion. Inspired by living cells, the development of mobile robots on the micron scale (microrobots) promises new capabilities for advancing human health, renewable energy, and environmental sustainability. To help pave the way towards this goal we develop practical recipes for applying computational and analytical tools to physics-based dynamical models of our microrobot experiments. We apply methods of criticism and validation to identify robust models for the motion of magnetic particles at curved interfaces, and identify optimal conditions for propulsion in our model system. We then develop tools for identifying optimal experimental conditions for most efficiently learning model parameters. By studying microscale actuation in depth, we seek to provide a roadmap of how to apply these computational tools to other microrobot design challenges, accelerating the scientific process. In Chapter 1, we focus on the actuation of magnetic particles adsorbed at curved liquid interfaces by external fields, a phenomenon that can be utilized for applications such as droplet mixing or propulsion. To optimize these behaviors, the development and validation of predictive models are essential. We employ Bayesian data analysis as a principled approach to infer model parameters from experimental observations, assess the capabilities of candidate models, and select the most plausible among them. Specifically, we identify and validate a dynamical model which accounts for the effects of gravity and tilting of the particle, a Janus sphere, at the interface. We show how this favored model can predict complex particle trajectories with micron-level accuracy across the range of driving fields considered. Chapter 2 builds on this modeling to develop the optimal properties of a mobile liquid droplet, driven by an adsorbed magnetic particle. This configuration enables the design of responsive emulsions, which can be actuated by a magnetic field. This work develops the properties of such a swimmer and validates our findings with an experimental realization of a ferromagnetic ellipsoid adsorbed onto a stationary water droplet in decane. Accounting for geometric differences, the model developed in the previous chapter is demonstrated to be accurate for this new system. We find that the configuration of the magnetic moment of our ellipsoid prohibits swimming of the assembly, but if it can be modified during fabrication, propulsion is possible. In Chapter 3 we show how automated experiments based on Bayesian inference and design can accurately and efficiently characterize another microscale propulsion system, the acoustic field within resonant chambers used to propel acoustic nanomotors. Repeated cycles of observation, inference, and design are guided by a physical model that describes the rate at which levitating particles approach the nodal plane. We show how this iterative process serves to discriminate between competing hypotheses and efficiently converges to accurate parameter estimates using only a few automated experiments. This work demonstrates how Bayesian methods can learn the parameters of nonlinear hierarchical models used to describe video microscopy data of active colloids. Finally, the forward-looking perspective in Chapter 4 illustrates how best to leverage these techniques and models to provide a path forward for self-guided microrobots. Existing microrobots based on field-driven particles rely on knowledge of the particle position and the target destination to control particle motion through fluid environments. These external control strategies are challenged by limited information and global actuation, where a common field directs multiple robots with unknown positions. We discuss how time-varying magnetic fields can be used to encode self-guided behaviors of magnetic particles conditioned on local environmental cues. Programming these behaviors is framed as a design problem: we seek to identify the design variables (e.g. particle shape, magnetization, elasticity, stimuli-response) that achieve the desired performance in a given environment. We discuss strategies for accelerating the design process using the methods developed in this thesis—including automated experiments, computational models, and statistical inference—as well as other approaches such as machine learning. Based on the current understanding of field-driven particle dynamics and existing capabilities for particle fabrication and actuation, we argue that self-guided microrobots with potentially transformative capabilities are close at hand. This research offers a unique contribution by demonstrating the practicality and efficiency of Bayesian computational methods in microrobot design, and provides a template that is applicable anywhere that physics-based dynamical models can be used to guide experimental effort.

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Supply planning is one of the key steps in an apartment building constructionproject, due to the repetitive nature of these projects where the constructionpace therefore has a crucial importance. However, if the working forceplanning and the materials planning are often acknowledged as important,the equipment supply planning can happen to be considered as secondary.Therefore less effort has been put in the tools used to make this planning.This master thesis is the result of a work in collaboration with the methodsdepartment at Eiffage Construction Habitat, one of the most important Frenchconstruction companies. It presents the implementation of a tool that automatesan important part of the equipment supply planning in order to gain efficiencyduring this planning process and to be able to focus deeper on the keyissues of the project. This tool allows to drastically reduce the time spentduring the supply planning for the equipment of the structural phase, bothregarding vertical works (walls and columns) and horizontal works (floors,beams and balconies). Along with making the planning more efficient, itallows to standardize the output documents and facilitate the work of theother departments with whom the methods department collaborates. Resultingfrom a case study and an internal survey, the implemented tool relies onthe Microsoft Visual Basic for Applications technology, allowing to staywithin the users’ range of mastered software, therefore improving the adoptionpotential of the tool. The results analysis showed a great satisfaction from theusers, both regarding the abilities of the tool and its form. / Resursplaneringen är ett av de viktigaste stegen i ett projekt för byggandeav flerbostadshus på grund av den repetitiva karaktären hos dessa projektdär bygghastigheten därför har en avgörande betydelse. Men om arbetskraftsplaneringenoch materialplaneringen ofta ses som viktiga kan planeringenav utrustningsförsörjningen råka betraktas som sekundär. Därför har mindreansträngningar lagts på de verktyg som används för att göra denna planering.Detta examensarbete är resultatet av ett arbete i samarbete med metodavdelningenvid Eiffage Construction Habitat, ett av de viktigaste franska byggföretagen.Arbetet presenterar implementeringen av ett verktyg som automatiseraren viktig del av planeringen av utrustningsförsörjningen för att få effektivitetunder denna planeringsprocess och för att kunna fokusera djupare på deviktigaste frågorna i projektet. Detta verktyg gör det möjligt att drastisktminska den tid som spenderas under leveransplaneringen för konstruktionsfasensutrustning, både när det gäller vertikala arbeten (väggar och pelare)och horisontella arbeten (golv, balkar och balkonger). Tillsammans med atteffektivisera planeringen möjliggör det att standardisera utdata och underlättaarbetet för de andra avdelningar som metodavdelningen samarbetar med.Till följd av ett studiefall och en intern undersökning är det implementeradeverktyget beroende av Microsoft Visual Basic for Applications-tekniken,vilket gör det möjligt att hålla sig till denprogramvara som användarnashar tillgång till och kan behärska, , vilket förbättrar möjligheter för attverktyget ska accepteras och använda verktyget. Resultatanalysen visade enstor tillfredsställelse från användarna, både vad gäller kan leverera och hurgränssnittet till användaren är utformat.