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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.
221

Workflow and Activity Modeling for Monitoring Surgical Procedures / Modélisation des activités chirurgicales et de leur déroulement pour la reconnaissance des étapes opératoires

Padoy, Nicolas 14 April 2010 (has links)
Le bloc opératoire est au coeur des soins délivrés dans l'hôpital. Suite à de nombreux développements techniques et médicaux, il devient équipé de salles opératoires hautement technologiques. Bien que ces changements soient bénéfiques pour le traitement des patients, ils accroissent la complexité du déroulement des opérations. Ils impliquent également la présence de nombreux systèmes électroniques fournissant de l'information sur les processus chirurgicaux. Ce travail s'intéresse au développement de méthodes statistiques permettant de modéliser le déroulement des processus chirurgicaux et d'en reconnaitre les étapes, en utilisant des signaux présents dans le bloc opératoire. Nous introduisons et formalisons le problème consistant à reconnaitre les phases réalisées au sein d'un processus chirurgical, en utilisant une représentation des chirurgies par une suite temporelle et multi-dimensionnelle de signaux synchronisés. Nous proposons ensuite des méthodes pour la modélisation, la segmentation hors-ligne et la reconnaissance en-ligne des phases chirurgicales. La méthode principale, une variante de modèle de Markov caché étendue par des variables de probabilités de phases, est démontrée sur deux applications médicales. La première concerne les interventions endoscopiques, la cholécystectomie étant prise en exemple. Les phases endoscopiques sont reconnues en utilisant des signaux indiquant l'utilisation des instruments et enregistrés lors de chirurgies réelles. La deuxième application concerne la reconnaissance des activités génériques d'une salle opératoire. Dans ce cas, la reconnaissance utilise de l'information 4D provenant d'un système de reconstruction multi-vues / The department of surgery is the core unit of the patient care system within a hospital. Due to continuous technical and medical developments, such departments are equipped with increasingly high-tech surgery rooms. This provides higher benefits for patient treatment, but also increases the complexity of the procedures' workflow. This also induces the presence of multiple electronic systems providing rich and various information about the surgical processes. The focus of this work is the development of statistical methods that permit the modeling and monitoring of surgical processes, based on signals available in the surgery room. We introduce and formalize the problem of recognizing phases within a workflow, using a representation of interventions in terms of multidimensional time-series formed by synchronized signals acquired over time. We then propose methods for the modeling, offline segmentation and on-line recognition of surgical phases. The main method, a variant of hidden Markov models augmented by phase probability variables, is demonstrated on two medical applications. The first one is the monitoring of endoscopic interventions, using cholecystectomy as illustrative surgery. Phases are recognized using signals indicating tool usage and recorded from real procedures. The second application is the monitoring of a generic surgery room workflow. In this case, phase recognition is performed by using 4D information from surgeries performed in a mock-up operating room in presence of a multi-view reconstruction system
222

Représentation et gestion des connaissances dans les environnements intérieurs mobiles / Knowledge representation and management in indoor mobile environments

Afyouni, Imad 17 September 2013 (has links)
Les systèmes d'information mobiles et ambiants liés à la localisation et à la navigation évoluent progressivement vers des environnements à petite échelle. La nouvelle frontière scientifique et technologique concerne les applications qui assistent les utilisateurs dans leurs déplacements et activités au sein d’espaces bâtis dits «indoor» (e.g., aéroports, musées, bâtiments). La recherche présentée par cette thèse développe une représentation de données spatiales d'un environnement «indoor» qui tient compte des dimensions contextuelles centrées sur l'utilisateur et aborde les enjeux de gestion de données mobiles. Un modèle de données «indoor» hiérarchique et sensible au contexte est proposé. Ce modèle intègre différentes dimensions du contexte en plus de la localisation des entités concernées, telles que le temps et les profils des utilisateurs. Ce modèle est basé sur une structure arborescente dans laquelle l'information spatiale est représentée à différents niveaux d'abstraction. Cette conception hiérarchique favorise un traitement adaptatif et efficace des Requêtes Dépendantes de la Localisation (RDL) qui sont considérées comme des éléments clés pour le développement des différentes catégories de services de géolocalisation sensibles au contexte. Un langage de requêtes continues est développé et illustré par des exemples de requêtes RDL. Ce langage exploite le concept des granules spatiales, et permet de représenter les requêtes continues et dépendantes de la localisation en prenant compte des préférences de l'utilisateur au moment de l'exécution.Cette approche de modélisation est complétée par le développement d'une architecture générique pour le traitement continu des requêtes RDL et par la conception et la mise en oeuvre de plusieurs algorithmes qui permettent un traitement efficace des requêtes dépendantes de la localisation sur des objets mobiles en «indoor». Plusieurs algorithmes de traitement continu des requêtes de recherche de chemin hiérarchique et des requêtes de zone appliquées à des objets statiques et/ou en mouvement sont présentés. Ces algorithmes utilisent une approche hiérarchique et incrémentale afin d'exécuter efficacement les requêtes RDL continues. Un prototype encapsulant le modèle de données hiérarchique, les opérateurs et les contraintes introduits dans le langage de requête ainsi que les différents algorithmes et méthodes pour la manipulation de requêtes RDL a été développé comme une extension du SGBD Open Source PostgreSQL. Une étude expérimentale des solutions développées a été menée pour étudier la performance et le passage à l'échelle à l'égard des propriétés intrinsèques des solutions proposées. / The range of applications in ambient information systems progressively evolves from large to small scale environments. This is particularly the case for applications that assist humans in navigation-related activities in indoor spaces (e.g., airports, museums, office buildings). The research presented by this Ph.D. dissertation develops a data and knowledge representation of an indoor environment that takes into account user-centred contextual dimensions and mobile data management issues. We introduce a hierarchical, context-dependent, and feature-based indoor spatial data model. This model takes into account additional contextual dimensions such as time, user profiles, and real-time events. The model is based on a tree structure in which location information is represented at different levels of abstraction. The hierarchical design favours performance and scalability of location-dependent query processing. A query grammar is developed and implemented on top of that model. This query language supports continuous location-dependent queries and takes into account user preferences at execution time. The concept of location granules is introduced at the query execution and presentation levels.This modelling approach is complemented by the development of a generic architecture for continuous query processing. Several algorithms for location dependent query processing over indoor moving objects have been designed and implemented. These algorithms include path searches and range queries applied to both static and moving objects. They are based on an incremental approach in order to execute continuous location-dependent queries.The operators and constraints introduced in the query language and the algorithms for location-dependent query processing have been implemented as a database extension of the open source DBMS PostgreSQL, and where the hierarchical network-based indoor data model has been developed at the logical level. Several experiments have been conducted to evaluate the scalability and performance of the whole framework.
223

Análise de arquiteturas e desenvolvimento de uma plataforma para residências inteligentes. / Architecture analysis and development of framework for intelligent houses.

Bolzani, Caio Augustus Morais 18 December 2009 (has links)
No início do século XX, poucas décadas depois do início da eletrificação das casas, o conceito de uma residência automatizada já era utilizado como símbolo de um futuro livre das tarefas domésticas. No entanto, mesmo com o desenvolvimento de tecnologias de suporte, a automação de residências nunca contemplou uma ampla disseminação e uso. Este trabalho realiza uma análise social, econômica, tecnológica, cultural e de saúde da sociedade, desde o início do século XX até os dias atuais, para entender o comportamento humano relativo ao ambiente residencial e identificar as possíveis causas que não favoreceram a implantação de sistemas de controle e automação nestes ambientes. Ele ainda propõe uma arquitetura de sistemas eletrônicos e computacionais para o ambiente residencial, baseada em um conjunto de requerimentos e de abstrações coerentes com o contexto socioeconômico vigente e factível diante das atuais disponibilidades tecnológicas, a fim de direcionar os esforços na área e fomentar o desenvolvimento de aplicações. Adicionalmente, é apresentada uma plataforma de desenvolvimento hardware, firmware e software , denominada Home Sapiens, cuja concepção, projeto e desenvolvimento foram feitos no contexto desta tese. Baseada em nós de controle distribuídos, ela permite o acesso aos dados provenientes de sensores, a geração de informações de contexto, a identificação de serviços e a manipulação das características do ambiente residencial segundo regras de decisão, planejamento e métodos de aprendizado baseados em técnicas de Inteligência Artificial / In the early twentieth century, a few decades after the beginning of the electrification of houses, the concept of an automated home was used as a symbol of a future free of domestic chores. However, even with the development of supporting technologies, the automation of homes never contemplated a wide dissemination and use. This paper presents an analysis social, economic, technological, cultural and health of society, from the early twentieth century to the present day, to understand human behavior on the residential environment and to identify possible causes that did not favor deployment of control systems and automation in these environments. It also proposes an architecture of computer and electronic systems for the residential environment, based on a set of applications and abstractions consistent with the current socioeconomic context and feasible under the available technology in order to direct efforts in the area and promote the development of applications. Additionally, the implementation of a framework hardware, firmware and software called Home Sapiens is presented, whose conception, design and development were made in the context of this thesis. Based on distributed control nodes, it provides access to data from sensors, the generation of information of context, the identification of services and handling characteristics of the residential environment in accordance with rules of decision, planning and learning methods based on Artificial Intelligence.
224

Design and implementation of WoBaLearn - a work-based context-aware mobile learning system / Conception et mise en œuvre du système d’apprentissage mobile contextualisé support du travail professionnel

Zhang, Bingxue 14 November 2014 (has links)
Un intérêt accru a été élevé sur les systèmes d'apprentissage mobiles contextualisé. Ces systèmes visent à fournir les supports d'apprentissage via des appareils mobiles et de les adapter aux besoins spécifiques de l'éducation, les caractéristiques personnelles et les circonstances particulières d'un apprenant ou un groupe d'apprenants interconnectés. L'apprentissage en milieu de travail est une approche essentielle pour promouvoir l'efficacité de travail et d'apprentissage des professionnels. Il est besoin ciblé, personnalisé, juste-à-temps et basé sur la localisation. Ces caractéristiques prédisent que le système d'apprentissage mobile contextualisé peut jouer un rôle dans la promotion de l'efficacité de l'apprentissage en milieu de travail. Cependant, il y a relativement peu de systèmes d'apprentissage mobiles contextualisé proposées pour le développement de l'apprentissage et de la compétence en situation de travail. Cet article propose la conception, la mise en œuvre et l'évaluation d’un système d'apprentissage mobile contextualisé pour le milieu professionnel, nommé WoBaLearn. Plus précisément, dans la thèse, nous avons travailler sur: (1) les théories de l'apprentissage mobile contextualisé et l'apprentissage en milieu de travail; (2) les approches pour la conception d'un système d'apprentissage mobile contextualisé pour le milieu professionnel; et (3) les technologies et les méthodologies de mettre en œuvre et de tester le système d'apprentissage conçu. Les principales contributions de cette thèse sont: 1) Construction d’un modèle de contexte hiérarchique et basé sur une ontologie pour l'apprentissage en milieu de travail Nous avons défini un modèle de contexte initial pour décrire l'information contextuelle de l'apprentissage mobile en milieu de travail, nommé WbML. Ce modèle adopte l'approche hiérarchique, et est construit par l'ontologie. 2) Proposition d’un ensemble de stratégies d'adaptation pour l'apprentissage en milieu de travail et un moteur d'apprentissage pour exécuter ces stratégies Nous avons proposé un ensemble de stratégies d'adaptation. Ces stratégies adapter les supports d'apprentissage en fonction du contexte d’apprentissage actuel. Nous avons proposé également un moteur d'adaptation qui exécute ces stratégies pour mettre en œuvre les adaptations d'apprentissage. 3) Conception de l’architecture d’un système d'apprentissage mobile contextualisé pour le milieu professionnel Combinant avec les bases conceptuelles sur le modèle de contexte, des contenus d'apprentissage, les stratégies d'adaptation et le moteur d'adaptation, nous avons proposé l'architecture de WoBaLearn système qui permet à WoBaLearn de réaliser des services d'apprentissage adaptatif. 4) Mise en œuvre du système et son évaluation avec une étude de cas Nous avons implémenté le système avec les technologies modernes, et mis une étude de cas pour évaluer ce système. Les résultats d'évaluation nous ont fourni la preuve que ce système peut offrir aux professionnels une expérience d'apprentissage satisfaisant et faciliter leurs activités de travail. / Increased interest has been shown in context-aware mobile learning systems. These systems aim to provide learning supports via mobile devices and adapt them to specific educational needs, personal characteristics and particular circumstances of an individual learner or a group of interconnected learners. Work-based learning is a crucial approach to promote professionals’ working and learning efficiency, which is need-targeted, personalized, just-in-time and location-based. These characteristics predict that context-aware mobile learning systems can play a role in promoting the effect of work-based learning. However, relatively few context-aware mobile learning systems are proposed for learning and competence development in work contexts. This dissertation proposes the design, implementation and evaluation of a context-aware mobile system for work-based learning, named WoBaLearn. More specifically, in the dissertation, we worked on: (1) the learning theories related to work-based context-aware mobile learning; (2) the approaches for designing a work-based context-aware mobile learning system; and (3) the technologies and methodologies for implementing and testing the designed system. The main contributions of this thesis are: 1) Proposal of an ontology-based hierarchical context model for work-based learning We defined an initial context model for describing contextual information in work-based mobile learning, named WbML. This model adopts a hierarchical designing approach which classifies con-text into a common layer and a domain layer. This approach improves the reusability of this context model. Also, the WbML context model is built based on ontology for describing context semantically. 2) Design of a set of adaptation strategies for work-based learning and an adaptation engine to execute these strategies We proposed a set of adaptation strategies concerning learning units selection, learning units sequence, learning units navigation, learning partners communication, and learning activities generation. These strategies adapt learning supports depending on professionals’ just-in-time learning con-text. We proposed also an adaptation engine which executes these proposed strategies to implement learning adaptations. 3) Construction of the WoBaLearn architecture Combined with the conceptual design bases about the context model, learning contents, adaptation strategies and adaptation engine, we proposed the system architecture of WoBaLearn which enables the WoBaLearn system to achieve the adaptive learning services. 4) Implementation of WoBaLearn We implemented the proposed system with modern technologies, and set a user study to evaluate it. Evaluation results provided us with the evidence that this system can offer professionals a satisfactory learning experience and facilitate their work activities.
225

Uma abordagem ciente de contexto e embasada por feedbacks para o gerenciamento de handovers em ambientes NGN / A context-aware and feedback-based approach for handover management in NGN

Lopes, Roberto Rigolin Ferreira 20 June 2012 (has links)
A evolução da computação móvel melhora a capacidade de comunicação e colaboração das pessoas. Os principais pilares desta transformação são: o desenvolvimento e produção de dispositivos móveis com capacidade multimídia e equipados com duas ou mais interfaces de rede, a disponibilidade de conectividade sem fio ubíqua e a popularização de aplicações sociais online. As redes sociais online merecem destaque pelas funcionalidades que permitem a criação e compartilhamento de conteúdo digital dentro de círculos sociais, também chamado de mídia social. Serviços na web anexam a localização geográfica do dispositivo ao conteúdo digital, criando as chamadas mídias sociais baseadas em localização. Equipadas com seus telefones e tablets, as pessoas estão criando e consumindo mídias sociais em qualquer lugar. Entretanto, é um desafio manter tais dispositivos móveis conectados nos ambientes de rede sem fio atuais e de próxima geração e.g., múltiplos provedores de acesso e múltiplas tecnologias de comunicação. Pesquisas recentes propõem componentes para o gerenciamento de conectividade sem fio que fazem uso simultâneo do contexto de conectividade atual e de um conjunto destes dados coletados no passado. Tais componentes são preditores de mobilidade, mecanismos de handover ou gerenciadores de mobilidade que utilizam dados de contexto de conectividade de forma particular para atingir seus propósitos. Na presente investigação, propomos uma metodologia que orquestra os principais componentes de gerenciamento de conectividade em um laço retro alimentado. Argumentamos que a coleta de dados de contexto de conectividade pode ser projetada como um sistema de sensoreamento, cujo sensores são as interfaces de rede sem fio. Como parte deste sistema de sensoriamento, os círculos sociais podem assistir o gerenciamento de conectividade compartilhando dados de contexto de conectividade. A ideia central é utilizar serviços baseados em localização para compartilhar dados de contexto de conectividade dentro dos círculos sociais. Desta forma, as redes sociais online adicionam escala para o sistema e permite colaboração em volta de dados de contexto recentes, locais, personalizados e sociais. O objetivo é melhorar experiências de conectividade sem fio e.g., métricas de QoS (Quality of Service) como: vazão, latência e qualidade do sinal. Relatamos como os dados de contexto de conectividade são manipulados com um modelo baseado em grafos e métricas como: intensidade do vértice e grau centralidade. Com isso, identificamos áreas com alta densidade de handovers, definimos a reputação dos usuários e revelamos a cobertura das redes. Resultados de experimentos mostram que a colaboração pode melhorar métricas de QoS de ~18 a ~30% se comparado ao uso de um preditor de mobilidade ou um sistema operacional moderno, respectivamente. Esta discussão se desdobra com foco na viabilidade da solução em termos de sobrecarga de armazenamento e consumo de energia. Os promissores resultados experimentais indicam que nossa solução pode melhorar experiências de conectividade sem fio de usuários móveis / The evolution of mobile computing improves communication and collaboration among people. The main pillars of this transformation are: the development and production of mobile devices with multimedia capabilities and equipped with two or more network interfaces, the availability of ubiquitous wireless connectivity and the popularity of online social applications. Online social networks noteworthy features that allow for the creation and sharing of digital content within social circles, also called textit Social Media. Web Services attach the geographic location of the device to the digital content, creating the so-called textit location-based social media. Equipped with their phones and tablets, people are creating and consuming social media anywhere. However, it is a challenge to keep such mobile devices connected in current and next generation wireless network environments textit e.g., multiple ISPs (Internet Service Provider) and multiple communication technologies. Recent researches proposes components for managing wireless connectivity that make simultaneous use of the current and past connectivity context data. Such components are mobility predictors, handovers mechanisms or mobility managers that use connectivity context data in a particular way to achieve its purposes. In this research, we propose feasiable a methodology that orchestrates the main components of the connectivity management in a feedback loop. We argue that the process of gathering connectivity context data can be designed as a sensing system, whose sensors are wireless network interfaces. As part of this sensing system, the social circles may assist the management of connectivity by sharing connectivity context data. The main idea is to use location-based services to share connectivity context data within social circles. Thus, online social networks add scale to the system and enables collaboration around recent, local, and social context data. The goal is to enhance wireless connectivity experiences in terms of QoS ( textit Quality of Service) metrics textit e.g., throughput, latency and signal quality. We report how this data is handled using complex networks metrics e.g., vertexs strength and centrality degree, to identify high density handover areas, define the mobile users reputation and to reveal the networks coverage. Real experiments showed that collaboration can improve QoS metrics from ~18 to ~30% if compared to just use a mobility predictor or a modern operational system, respectively. The discussion unfolds with focus on the collaborations efficiency as function of time, number of users, discovered area size and mobility patterns. The promising experimental results indicate that our solution can enhance mobile users wireless connectivity experiences
226

Análise de arquiteturas e desenvolvimento de uma plataforma para residências inteligentes. / Architecture analysis and development of framework for intelligent houses.

Caio Augustus Morais Bolzani 18 December 2009 (has links)
No início do século XX, poucas décadas depois do início da eletrificação das casas, o conceito de uma residência automatizada já era utilizado como símbolo de um futuro livre das tarefas domésticas. No entanto, mesmo com o desenvolvimento de tecnologias de suporte, a automação de residências nunca contemplou uma ampla disseminação e uso. Este trabalho realiza uma análise social, econômica, tecnológica, cultural e de saúde da sociedade, desde o início do século XX até os dias atuais, para entender o comportamento humano relativo ao ambiente residencial e identificar as possíveis causas que não favoreceram a implantação de sistemas de controle e automação nestes ambientes. Ele ainda propõe uma arquitetura de sistemas eletrônicos e computacionais para o ambiente residencial, baseada em um conjunto de requerimentos e de abstrações coerentes com o contexto socioeconômico vigente e factível diante das atuais disponibilidades tecnológicas, a fim de direcionar os esforços na área e fomentar o desenvolvimento de aplicações. Adicionalmente, é apresentada uma plataforma de desenvolvimento hardware, firmware e software , denominada Home Sapiens, cuja concepção, projeto e desenvolvimento foram feitos no contexto desta tese. Baseada em nós de controle distribuídos, ela permite o acesso aos dados provenientes de sensores, a geração de informações de contexto, a identificação de serviços e a manipulação das características do ambiente residencial segundo regras de decisão, planejamento e métodos de aprendizado baseados em técnicas de Inteligência Artificial / In the early twentieth century, a few decades after the beginning of the electrification of houses, the concept of an automated home was used as a symbol of a future free of domestic chores. However, even with the development of supporting technologies, the automation of homes never contemplated a wide dissemination and use. This paper presents an analysis social, economic, technological, cultural and health of society, from the early twentieth century to the present day, to understand human behavior on the residential environment and to identify possible causes that did not favor deployment of control systems and automation in these environments. It also proposes an architecture of computer and electronic systems for the residential environment, based on a set of applications and abstractions consistent with the current socioeconomic context and feasible under the available technology in order to direct efforts in the area and promote the development of applications. Additionally, the implementation of a framework hardware, firmware and software called Home Sapiens is presented, whose conception, design and development were made in the context of this thesis. Based on distributed control nodes, it provides access to data from sensors, the generation of information of context, the identification of services and handling characteristics of the residential environment in accordance with rules of decision, planning and learning methods based on Artificial Intelligence.
227

Composição de serviços em ambientes pervasivos: um modelo de referência. / Services composition in pervasive environments: a reference model.

Juan Carlos Zuñiga Torres 17 June 2013 (has links)
Ambientes Pervasivos são ambientes povoados por diversos dispositivos (sensores, atuadores, etc.) e aplicações de software (locais ou distribuídas) incorporadas nestes ambientes físicos de forma transparente para o usuário. Ambientes deste tipo devem ser capazes de interagir e satisfazer as requisições do usuário de forma autônoma e transparente. Nesse sentido, um dos maiores desafios de pesquisa em ambientes pervasivos é a de estabelecer mecanismos automáticos para compor, de forma dinâmica, funcionalidades que satisfaçam as requisições dos usuários. Nesse sentido, nós partimos da hipótese que mecanismos automáticos de interação entre ambientes e usuários podem ser abordados como um problema de composição automática de serviços em ambientes pervasivos. Portanto, nossa proposta é desenvolver um modelo referência, a partir do qual podem ser implementados sistemas que permitam ao ambiente pervasivo interagir com o usuário de forma natural, automática e dinâmica. Desta forma, o sistema de composição de serviços gerencia e automatiza o processo de resolução de requisições feitas pelo usuário (de forma implícita e/ou explicita) através das funcionalidades (serviços) disponíveis no ambiente ou através de novas funcionalidades criadas pelo processo de composição. Para tal fim, este trabalho apresenta um Modelo de Referência que permita projetar, implementar e avaliar sistemas de composição de serviços que gerenciem e automatizem o processo de interação em diversos tipos de ambientes pervasivos. Nossa proposta traz vantagens como: o baixo acoplamento e a interoperabilidade, isto porque é possível selecionar, integrar e reutilizar de forma eficiente e efetiva serviços heterogêneos provenientes de diversos tipos de dispositivos e/ou aplicações. Além disso, o modelo ontológico WSMO (Web Services Modelling Ontology) nos permite descrever semanticamente as capacidades dos serviços como também as informações contextuais presentes no ambiente, o que torna nosso sistema mais perto de um ambiente pervasivo real como o idealizado por Mark Weiser. / Pervasive environments are populated by several devices (sensors, actuators, etc.) and software applications (local or distributed) incorporated these physical environments transparently to the user. Environments of this type should be able to interact and process user requests autonomously and transparently. In this sense, one of the biggest research challenges in pervasive environments is to establish automatic mechanisms to compose dynamically, features that meet the user requirements. In this sense, we set the hypothesis that automatic mechanisms of interaction between users and environments can be addressed as a problem of automatic composition of services in pervasive environments. Therefore, our proposal is to develop a reference model, from which systems can be implemented to enable the pervasive environment interact with the user in a natural, automatic and dynamic. Thus, the system service composition management and automates the process of resolving requests made by the user (implicitly and / or explicitly) through the functionality (services) available in the environment or through new features created by the process of composition. To this end, this paper presents a Reference Model that allows to design, implement and evaluate systems of composition of services that manage and automate the interaction process in different types of pervasive environments. Our proposal brings benefits such as loose coupling and interoperability, because it is possible to select, integrate and reuse in an efficient and effective heterogeneous services from different types of devices and / or applications. Furthermore, the ontological model WSMO (Web Services Modeling Ontology) allows us to semantically describe the capabilities of the services as well as contextual information in the environment, which makes our system closer to a real pervasive environment as conceived by Mark Weiser.
228

A Privacy-Preserving, Context-Aware, Insider Threat prevention and prediction model (PPCAITPP)

Tekle, Solomon Mekonnen 07 1900 (has links)
The insider threat problem is extremely challenging to address, as it is committed by insiders who are trusted and authorized to access the information resources of the organization. The problem is further complicated by the multifaceted nature of insiders, as human beings have various motivations and fluctuating behaviours. Additionally, typical monitoring systems may violate the privacy of insiders. Consequently, there is a need to consider a comprehensive approach to mitigate insider threats. This research presents a novel insider threat prevention and prediction model, combining several approaches, techniques and tools from the fields of computer science and criminology. The model is a Privacy- Preserving, Context-Aware, Insider Threat Prevention and Prediction model (PPCAITPP). The model is predicated on the Fraud Diamond (a theory from Criminology) which assumes there must be four elements present in order for a criminal to commit maleficence. The basic elements are pressure (i.e. motive), opportunity, ability (i.e. capability) and rationalization. According to the Fraud Diamond, malicious employees need to have a motive, opportunity and the capability to commit fraud. Additionally, criminals tend to rationalize their malicious actions in order for them to ease their cognitive dissonance towards maleficence. In order to mitigate the insider threat comprehensively, there is a need to consider all the elements of the Fraud Diamond because insider threat crime is also related to elements of the Fraud Diamond similar to crimes committed within the physical landscape. The model intends to act within context, which implies that when the model offers predictions about threats, it also reacts to prevent the threat from becoming a future threat instantaneously. To collect information about insiders for the purposes of prediction, there is a need to collect current information, as the motives and behaviours of humans are transient. Context-aware systems are used in the model to collect current information about insiders related to motive and ability as well as to determine whether insiders exploit any opportunity to commit a crime (i.e. entrapment). Furthermore, they are used to neutralize any rationalizations the insider may have via neutralization mitigation, thus preventing the insider from committing a future crime. However, the model collects private information and involves entrapment that will be deemed unethical. A model that does not preserve the privacy of insiders may cause them to feel they are not trusted, which in turn may affect their productivity in the workplace negatively. Hence, this thesis argues that an insider prediction model must be privacy-preserving in order to prevent further cybercrime. The model is not intended to be punitive but rather a strategy to prevent current insiders from being tempted to commit a crime in future. The model involves four major components: context awareness, opportunity facilitation, neutralization mitigation and privacy preservation. The model implements a context analyser to collect information related to an insider who may be motivated to commit a crime and his or her ability to implement an attack plan. The context analyser only collects meta-data such as search behaviour, file access, logins, use of keystrokes and linguistic features, excluding the content to preserve the privacy of insiders. The model also employs keystroke and linguistic features based on typing patterns to collect information about any change in an insider’s emotional and stress levels. This is indirectly related to the motivation to commit a cybercrime. Research demonstrates that most of the insiders who have committed a crime have experienced a negative emotion/pressure resulting from dissatisfaction with employment measures such as terminations, transfers without their consent or denial of a wage increase. However, there may also be personal problems such as a divorce. The typing pattern analyser and other resource usage behaviours aid in identifying an insider who may be motivated to commit a cybercrime based on his or her stress levels and emotions as well as the change in resource usage behaviour. The model does not identify the motive itself, but rather identifies those individuals who may be motivated to commit a crime by reviewing their computer-based actions. The model also assesses the capability of insiders to commit a planned attack based on their usage of computer applications and measuring their sophistication in terms of the range of knowledge, depth of knowledge and skill as well as assessing the number of systems errors and warnings generated while using the applications. The model will facilitate an opportunity to commit a crime by using honeypots to determine whether a motivated and capable insider will exploit any opportunity in the organization involving a criminal act. Based on the insider’s reaction to the opportunity presented via a honeypot, the model will deploy an implementation strategy based on neutralization mitigation. Neutralization mitigation is the process of nullifying the rationalizations that the insider may have had for committing the crime. All information about insiders will be anonymized to remove any identifiers for the purpose of preserving the privacy of insiders. The model also intends to identify any new behaviour that may result during the course of implementation. This research contributes to existing scientific knowledge in the insider threat domain and can be used as a point of departure for future researchers in the area. Organizations could use the model as a framework to design and develop a comprehensive security solution for insider threat problems. The model concept can also be integrated into existing information security systems that address the insider threat problem / Information Science / D. Phil. (Information Systems)
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互動敘事中自動產生符合情境的攝影機規劃 / Context-aware camera planning for interactive storytelling

陳嘉豪, Chan, Ka-Hou Unknown Date (has links)
在互動敘事(Interactive Storytelling)的應用中,適當的攝影機規劃能幫助我們呈現虛擬世界中所發生的故事。在本研究中,我們設計了一個可以讓使用者設計互動敘事的應用平台-IMStory。針對故事創作,我們提供了一個故事腳本的描述語言及其剖析器,當使用者撰寫好互動故事之後,系統便能夠根據故事情境內容及與使用者互動的結果產生出符合情境的自動攝影機規劃系統。在此系統中,我們建立了一個能夠讓攝影機理解故事腳本的關係模型,建立虛擬攝影機組態與「故事情境」間的對應關係,即時找出更能表達當時情境的拍攝方式與架設位置。最後,我們設計了一個場景劇本進行實驗,在實驗中,我們的系統能夠即時因應場景中角色物件的位置作出即時的攝影機規劃,並且能夠配合互動環境中改變的情境參數而使用適合的攝影模組,產生出符合攝影學法則且賦有敘事能力的鏡頭。透過我們的方法,希望能提供一個更加有敘事能力的互動敘事平台。 / In an 3D interactive storytelling system, virtual camera is the key for us to understand what happens in the virtual world. In this thesis, we have designed an intelligent camera planning system for interactive storytelling, in which story plots are influenced by the user’s actions. Since the story flow cannot be determined in advance, it is essential to utilize real-time camera control to express the story for given spatial relationships between characters and objects. A script language and its parser were designed for our storytelling system (IMStory) to describe events in the story as well as the contexts associated with the events to model the properties of a story for camera control. We have developed a camera planning system by mapping contexts parameters into appropriate camera control parameters. We have implemented the 3D interactive storytelling system and demonstrated its capabilities with several examples. The camera planning system is shown to perform in real time, and the generated shots are more expressive in establishing the relation between camera configurations and story context.
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Using Availability Indicators to Enhance Context-Aware Family Communication Applications

Nagel, Kristine Susanne 05 July 2006 (has links)
Family conversation between homes is difficult to initiate at mutually agreeable times as neither participant has exact knowledge of the other's activities or intentions. Whether calling to plan an important family gathering or simply to connect with family members, the question is: Is now a good time to call? People expect friends and family to learn their activity patterns and to minimize interruptions when calling. Can technology provide awareness cues to the caller, even prior to the initiation of the call? This research focuses on sampling the everyday activities of home life to determine environmental factors, which may serve as an indicator for availability. These external factors may be effective for identifying household routines of availability and useful in determining when to initiate conversation across homes. Several workplace studies have shown a person's interruptibility can be reliably assessed and modeled from specific environmental cues; this work looks for similar predictive power in the home. Copresence, location, and activity in the home were investigated as correlates to availability and for their effectiveness within the social protocol of family conversation. These studies indicate there are activities that can be sensed, either in real-time or over some time span, that correlate to self-reported availability. However, the type and amount of information shared is dependent upon individual preferences, social accessibility, and patterns of activities. This research shows friends and family can improve their predictions of when to call if provided additional context, and suggests that abstract representations of either routines or explicit availability status is sufficient and may be preferred by providers. Availability prediction is feasible in the home and useful to those outside the home, but the level of detail to provide in particular situations needs further study. This work has implications for the development of groupware systems, the automatic sensing of activity to deal with interruption, and activity recognition in the home.

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