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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Techniques for Supporting Prediction of Security Breaches in Critical Cloud Infrastructures Using Bayesian Network and Markov Decision Process

January 2015 (has links)
abstract: Emerging trends in cyber system security breaches in critical cloud infrastructures show that attackers have abundant resources (human and computing power), expertise and support of large organizations and possible foreign governments. In order to greatly improve the protection of critical cloud infrastructures, incorporation of human behavior is needed to predict potential security breaches in critical cloud infrastructures. To achieve such prediction, it is envisioned to develop a probabilistic modeling approach with the capability of accurately capturing system-wide causal relationship among the observed operational behaviors in the critical cloud infrastructure and accurately capturing probabilistic human (users’) behaviors on subsystems as the subsystems are directly interacting with humans. In our conceptual approach, the system-wide causal relationship can be captured by the Bayesian network, and the probabilistic human behavior in the subsystems can be captured by the Markov Decision Processes. The interactions between the dynamically changing state graphs of Markov Decision Processes and the dynamic causal relationships in Bayesian network are key components in such probabilistic modelling applications. In this thesis, two techniques are presented for supporting the above vision to prediction of potential security breaches in critical cloud infrastructures. The first technique is for evaluation of the conformance of the Bayesian network with the multiple MDPs. The second technique is to evaluate the dynamically changing Bayesian network structure for conformance with the rules of the Bayesian network using a graph checker algorithm. A case study and its simulation are presented to show how the two techniques support the specific parts in our conceptual approach to predicting system-wide security breaches in critical cloud infrastructures. / Dissertation/Thesis / Masters Thesis Computer Science 2015
92

The Development and Engineering Application of a Fiber Reinforced Hybrid Matrix Composite for Structural Retrofitting and Damage Mitigation

January 2013 (has links)
abstract: Civil infrastructures are susceptible to damage under the events of natural or manmade disasters. Over the last two decades, the use of emerging engineering materials, such as the fiber-reinforced plastics (FRPs), in structural retrofitting have gained significant popularity. However, due to their inherent brittleness and lack of energy dissipation, undesirable failure modes of the FRP-retrofitted systems, such as sudden laminate fracture and debonding, have been frequently observed. In this light, a Carbon-fiber reinforced Hybrid-polymeric Matrix Composite (or CHMC) was developed to provide a superior, yet affordable, solution for infrastructure damage mitigation and protection. The microstructural and micromechanical characteristics of the CHMC was investigated using scanning electron microscopy (SEM) and nanoindentation technique. The mechanical performance, such as damping, was identified using free and forced vibration tests. A simplified analytical model based on micromechanics was developed to predict the laminate stiffness using the modulus profile tested by the nanoindentation. The prediction results were verified by the flexural modulus calculated from the vibration tests. The feasibility of using CHMC to retrofit damaged structural systems was investigated via a series of structural component level tests. The effectiveness of using CHMC versus conventional carbon-fiber reinforced epoxy (CF/ epoxy) to retrofit notch damaged steel beams were tested. The comparison of the test results indicated the superior deformation capacity of the CHMC retrofitted beams. The full field strain distributions near the critical notch tip region were experimentally determined by the digital imaging correlation (DIC), and the results matched well with the finite element analysis (FEA) results. In the second series of tests, the application of CHMC was expanded to retrofit the full-scale fatigue-damaged concrete-encased steel (or SRC) girders. Similar to the notched steel beam tests, the CHMC retrofitted SRC girders exhibited substantially better post-peak load ductility than that of CF/ epoxy retrofitted girder. Lastly, a quasi-static push over test on the CHMC retrofitted reinforced concrete shear wall further highlighted the CHMC's capability of enhancing the deformation and energy dissipating potential of the damaged civil infrastructure systems. Analytical and numerical models were developed to assist the retrofitting design using the newly developed CHMC material. / Dissertation/Thesis / Ph.D. Civil and Environmental Engineering 2013
93

Critical infrastructure protection by advanced modelling, simulation and optimization for cascading failure mitigation and resilience / Protection des Infrastructures Essentielles par Advanced Modélisation, simulation et optimisation pour l’atténuation et résilience de défaillance en cascade

Fang, Yiping 02 February 2015 (has links)
Sans cesse croissante complexité et l'interdépendance des infrastructures critiques modernes, avec des environs de risque plus en plus complexes, posent des défis uniques pour leur exploitation sûre, fiable et efficace. L'objectif de la présente thèse est sur la modélisation, la simulation et l'optimisation des infrastructures critiques (par exemple, les réseaux de transmission de puissance) à l'égard de leur vulnérabilité et la résilience aux défaillances en cascade. Cette étude aborde le problème en modélisant infrastructures critiques à un niveau fondamental, en se concentrant sur la topologie du réseau et des modèles de flux physiques dans les infrastructures critiques. Un cadre de modélisation hiérarchique est introduit pour la gestion de la complexité du système. Au sein de ces cadres de modélisation, les techniques d'optimisation avancées (par exemple, non-dominée de tri binaire évolution différentielle (NSBDE) algorithme) sont utilisés pour maximiser à la fois la robustesse et la résilience (capacité de récupération) des infrastructures critiques contre les défaillances en cascade. Plus précisément, le premier problème est pris à partir d'un point de vue de la conception du système holistique, c'est-à-dire certaines propriétés du système, tels que ses capacités de topologie et de liaison, sont redessiné de manière optimale afin d'améliorer la capacité de résister à des défaillances systémiques de système. Les deux modèles de défaillance en cascade topologiques et physiques sont appliquées et leurs résultats correspondants sont comparés. En ce qui concerne le deuxième problème, un nouveau cadre est proposé pour la sélection optimale des mesures appropriées de récupération afin de maximiser la capacité du réseau d’infrastructure critique de récupération à partir d'un événement perturbateur. Un algorithme d'optimisation de calcul pas cher heuristique est proposé pour la solution du problème, en intégrant des concepts fondamentaux de flux de réseau et le calendrier du projet. Exemples d'analyse sont effectués en se référant à plusieurs systèmes de CI réalistes. / Continuously increasing complexity and interconnectedness of modern critical infrastructures, together with increasingly complex risk environments, pose unique challenges for their secure, reliable, and efficient operation. The focus of the present dissertation is on the modelling, simulation and optimization of critical infrastructures (CIs) (e.g., power transmission networks) with respect to their vulnerability and resilience to cascading failures. This study approaches the problem by firstly modelling CIs at a fundamental level, by focusing on network topology and physical flow patterns within the CIs. A hierarchical network modelling technique is introduced for the management of system complexity. Within these modelling frameworks, advanced optimization techniques (e.g., non-dominated sorting binary differential evolution (NSBDE) algorithm) are utilized to maximize both the robustness and resilience (recovery capacity) of CIs against cascading failures. Specifically, the first problem is taken from a holistic system design perspective, i.e. some system properties, such as its topology and link capacities, are redesigned in an optimal way in order to enhance system’s capacity of resisting to systemic failures. Both topological and physical cascading failure models are applied and their corresponding results are compared. With respect to the second problem, a novel framework is proposed for optimally selecting proper recovery actions in order to maximize the capacity of the CI network of recovery from a disruptive event. A heuristic, computationally cheap optimization algorithm is proposed for the solution of the problem, by integrating foundemental concepts from network flows and project scheduling. Examples of analysis are carried out by referring to several realistic CI systems.
94

An information infrastructure design to support home care of warfarin users: problems and possibilities

Larsson, John January 2016 (has links)
The anti-coagulant warfarin is consumed by around 200 000 people in Sweden every year. There are many dose affecting factors, and if the dose is wrong the consequences can be severe. Hence patients are required to regularly have their coagulation ability tested so that the dosage can be adjusted if needed. In this study the dosage regulation processes of warfarin in Swedish home care are examined through a case study, where-after an information infrastructure design is created that could support the identified needs. The proposed design is formed through combining three separate IT-capabilities: a general purpose health care platform, a warfarin specialist software and a medication reminder application. The design was guided by the application of the information infrastructure design rules with the aim of uncovering problems and possibilities associated with this design approach. By applying the information infrastructure design rules a technical architecture could successfully be created. Additionally, information exchange specifications and important decision making points could be identified or solved successfully. However the design rules were found to assume an unlikely level of openness and to lack a focus on organizational and legal factors which make them difficult to apply in practice.
95

From tailoring to appropriation support: Negotiating groupware usage

Pipek, V. (Volkmar) 21 January 2005 (has links)
Abstract This thesis contributes to the field of collaborative information systems and Computer-Supported Cooperative Work (CSCW). It extends the notion of technological support for design activities "in use" beyond providing the flexibility to tailor collaborative software, to provide means to support the appropriation process of these tools in their application fields. Two long-term studies on the evolution of usages of collaborative software in a German authority and in a network of freelancers in the field of consulting form the foundation of this work. Based on the experience there, it was possible to identify user activities that drive the appropriation process and to establish a perspective on the appropriation of a Groupware as a social process. Appropriation can be described as a collaborative effort of end users, who perform "appropriation activities" to make sense of the software in their work context. Besides activities to configure the software to fit into the technological, organisational and individual work context of the users ('Tailoring'), there is a larger area of technology-related communication, demonstration and negotiation activities aimed at establishing a shared understanding of how a software artefact works and what it can contribute to the shared work context. The mutual shaping of the technology and organisational contexts resemble an ongoing design process that end users perform largely without any involvement of professional developers. This perspective is the guiding line for developing means for "Appropriation Support", i.e., means to support the appropriation activities that end users perform. To inform the design of appropriation support measures and functions, current approaches that capture the collaborative dimensions of tailoring, and the necessities of 'discourse ergonomics' for technology-related online communication are explored. The trend to work with a tool 'infrastructure' instead of monolithic Groupware tools is a complicating yet important secondary consideration here, since it demonstrates the necessity to offer support 'beyond one tool' to support a use-oriented perspective on appropriation. The resulting idea of 'Use Discourse Environments' as a main concept for appropriation support which captures the activities of communication, demonstration and negotiation as well as the activity of tailoring (where possible) was implemented and evaluated in two prototypes that refer to the application fields of the initial studies. The idea of integrating online discourse, tool representations and tailoring facilities served as a guideline for the use discourse both in an event notification service as well as in the 'Online Future Workshop' that addressed a shared inter-organisational software development infrastructure. Based on the evaluations, design recommendations for appropriation support are made, and the problematic nature of appropriation activities as 'infrastructural work' versus the 'productive work' that end users consider their main area of work is addressed. The thesis concludes with a vision of collaborative software tools that do not only provide their original services, but also address end users as a 'virtual community of technology practice'.
96

Impact des infrastructures de transport sur la croissance économique : le cas du Maroc / Impact of transport infrastructure on economic growth : the case of Morocco

Oulmakki, Ouail 16 October 2015 (has links)
Les infrastructures de transport sont des biens publics dont l'importance a été démontrée dans la littérature économique depuis les travaux fondateurs des nouvelles théories de la croissance endogène, de la nouvelle économie géographique, ainsi que les études empiriques menées dans plusieurs pays. Notre travail de recherche s'intéresse aux infrastructures de transport dans les pays en développement (PED) avec une application au cas du Maroc.La thèse se présente en deux parties, la première met en évidence le rôle des infrastructures de transport dans l'économie à travers une revue de la littérature théorique et empirique ainsi que la présentation des différentes approches économétriques de modélisation du capital public. Nous étudions le cas du Maroc à travers une étude économétrique par un modèle vectoriel à correction d'erreur permettant d'analyser les relations dynamiques à long terme entre capital public et PIB ainsi que les effets de causalité. Puis, nous démontrons avec un modèle autorégressif l'impact des investissements autoroutiers sur le PIB/hab et l'amélioration de l'accessibilité.La deuxième partie de la thèse s'intéresse aux effets des infrastructures de transport sur la croissance des 16 régions marocaines et les disparités entre ces régions sous l'effet du capital public routier et autoroutier. Nous nous basons dans notre recherche, sur les travaux de Charlot (1999) et Charlot et Schmitt (2002) sur les régions françaises, sur les travaux de Marquez, Ramajo et Hewings (2011) s'intéressant au rôle du capital public sur la croissance régionale des provinces espagnoles, ainsi que sur de l'étude de Malyadi (2011) pour le cas du Maroc. Du point de vue théorique, notre approche se situe au croisement des théories de la croissance endogène et de la nouvelle économie géographique.La progression de la thèse se fait dans un ordre décroissant en termes d'espace étudié, partant du cadre national au cadre régional en terminant par un cas local de l'industrie automobile au Maroc pour explorer les liens entre infrastructure de transport et industrialisation régionale / Transport infrastructures are public goods. Their importance is demonstrated in the literature since the seminal works of the endogenous growth theory, new economic geography, as well as empirical studies conducted in several countries. Our research focuses on the transport infrastructure in developing countries with an application to the case of Morocco. This thesis is divided in two parts. The first one highlights the role of transport infrastructure in the economy through a review of theoretical and empirical literature and the presentation of different econometric modeling approaches. Then, we study the case of Morocco by using econometric approach of vector error correction model to analyze the long-term dynamic relationships between GDP, public capital and the causality effects. Then, we demonstrate with an autoregressive model the impact of highway investments on GDP / capita and improving accessibility. The second part of our research focuses on the effects of transport infrastructure on the economic growth of 16 Moroccan regions, and the differences between these regions as a result of road and highway public capital allocation. We follow in our research Charlot (1999), Charlot and Schmitt (2002) on French regions, and Marquez, Ramajo and Hewings (2011) applied on Spanish provinces. After, we study the evolution of urban primacy in Morocco by focusing our analysis to the structural role of transport infrastructure. We use gravity models to explore spatial interactions between Moroccan regions. Finally, we are interested in the region of Tangier in Morocco. We study the case of the Tangier-Med port as transport infrastructure. We analyze the impacts of this port on the economic dynamics of this region and the location of productive activities.
97

Service-oriented Geoprocessing in Spatial Data Infrastructures

Müller, Matthias 19 May 2016 (has links) (PDF)
Many of the ongoing activities towards establishing SDI on a regional, national, and international level are focused on data sharing and dissemination. Next to data access and visualisation, data processing is a third important pillar of GIS which can generate new insights by creating derived data or conducting computational analyses on original data sets. Within today’s largely data-centric SDI, two major challenges were identified that stand in the way of ubiquitous geoprocessing: The ability to use and exchange implementations of geoprocessing functions as freely as geographic data and the ability to describe, communicate and catalogue existing functionality on the Web. This thesis evaluates the moving code approach as an alternative to client–server processing in a distributed SDI. While classical client–server configurations move pieces of data between remote processing services, data services, and clients over the network, moving code setups consider the transfer of portable software components to the location of data or the location of computing resources. To exchange implementations of geoprocessing functions at a larger scale, a Web based code sharing architecture is proposed. For improved descriptions of geoprocessing functions, WPS process descriptions are suggested as an interface description language. They are enhanced by a hierarchical profiling approach that permits different levels of granularity in the functional descriptions.
98

Interoperable Information Exchange, Resource Discovery, and Service Quality Monitoring Across Virtual Organizations in Distributed Research Infrastructures

Kálmán, Tibor 08 November 2016 (has links)
No description available.
99

Aide à l'exploration des propriétés structurelles d'un réseau de transport : conception d'un modèle pour l'analyse, la visualisation et l'exploration d'un réseau de transport / Support for exploration of the structural properties of transportation network : designing a model for analysis, visualization and exploration of a transportation network

Mermet, Eric 04 March 2011 (has links)
Un réseau de transport est un objet géographique complexe possédant plusieurs dimensions : géométrique, topologique, métrique et relationnelle. À partir de ces dimensions, il est possible d'effectuer une analyse se situant entre l'analyse descriptive des composantes issues des bases de données et l'analyse fonctionnelle reposant sur des paramètres anthropiques. Cette analyse dite structurelle permet de mettre en évidence certaines propriétés du réseau sans contexte d'usage. Elle est basée sur la construction et l'analyse d'indicateurs basés sur les relations proposées par le réseau : les indicateurs relationnels. Ils mettent en évidence ses potentialités relationnelles ; c'est à dire en quoi celui-ci par sa structure etl'organisation spatiale et topologique de ses composantes prédispose à la mise en relation plus ou moins aisée de lieux de l'espace. Notre travail consiste en la conception d'un modèle pour l'analyse et l'exploration des propriétés structurelles d'un réseau de transport. Ce type d'analyse engendre une complexité combinatoire liée au nombre de relations sur le réseau, une complexité algorithmique liée aux calculs des indicateurs et une complexité visuelle liée à la difficulté de mettre en valeur des informations. Le modèle proposé vise à faciliter à l'utilisateur l'analyse exploratoire des propriétés structurelles du réseau par la création de cartes exploratoires. Notre modèle comprend deux parties. La première permet de réaliser des cartes statiques d'exploration. La seconde permet la combinaison visuelle de cartes en s'appuyant sur un langage graphique. Les deux aspects du modèle ont été développés dans un prototype logiciel baptisé GeoGraphLab / A transportation network is a complex spatial system characterized by four dimension types : geometric, topological, metric and relational. Thanks to these dimensions, it is possible to perform analysis situated in between the descriptive analysis of components from databases and functional analysis based on anthropogenic parameters. This analysis called structural helps to emphasize some properties of the network without usage context. It is established on the construction and analysis of indicators based on the relationship generated by the network: the relational indicators. They highlight their relational possibilities ; ie how their structure and spatial organization and topology of their components predispose to connect places in space in more or less easy way. Our work consists of designing a model for analysis and exploration of the structural properties of a transportation network. This type of analysis leads to a combinatorial complexity related to the number of relationships within the network, algorithmic complexity related to the calculation of indicators and visual complexity related to the difficulty to emphasize information. The proposed model aims to supply the user with the exploratory analysis of structural properties of the network by creating exploratory maps. Our model is composed of two parts. The first one allows to prepare static maps of exploration. The second one enables the visual combination of maps based on a graphic language. Both aspects of the model were developed in a prototype software called GeoGraphLab
100

Création d'un outil d'évaluation des coûts des infrastructures municipales souterraines selon différents facteurs d'influences

Fréchette, Richard January 2018 (has links) (PDF)
No description available.

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