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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.
141

A Distributed Architecture for Computing Context in Mobile Devices

Dargie, Waltenegus 27 May 2006 (has links) (PDF)
Context-aware computing aims at making mobile devices sensitive to the social and physical settings in which they are used. A necessary requirement to achieve this goal is to enable those devices to establish a shared understanding of the desired settings. Establishing a shared understanding entails the need to manipulate sensed data in order to capture a real world situation wholly, conceptually, and meaningfully. Quite often, however, the data acquired from sensors can be inexact, incomplete, and/or uncertain. Inexact sensing arises mostly due to the inherent limitation of sensors to capture a real world phenomenon precisely. Incompleteness is caused by the absence of a mechanism to capture certain real-world aspects; and uncertainty stems from the lack of knowledge about the reliability of the sensing sources, such as their sensing range, accuracy, and resolution. The thesis identifies a set of criteria for a context-aware system to capture dynamic real-world situations. On the basis of these criteria, a distributed architecture is designed, implemented and tested. The architecture consists of Primitive Context Servers, which abstract the acquisition of primitive contexts from physical sensors; Aggregators, to minimise error caused by inconsistent sensing, and to gather correlated primitive contexts pertaining to a particular entity or situation; a Knowledge Base and an Empirical Ambient Knowledge Component, to model dynamic properties of entities with facts and beliefs; and a Composer, to reason about dynamic real-world situations on the basis of sensed data. Two additional components, namely, the Event Handler and the Rule Organiser, are responsible for dynamically generating context rules by associating decision events ? signifying a user?s activity ? with the context in which those decision events are produced. Context-rules are essential elements with which the behaviour of mobile devices can be controlled and useful services can be provided. Four estimation and recognition schemes, namely, Fuzzy Logic, Hidden Markov Models, Dempster-Schafer Theory of Evidence, and Bayesian Networks, are investigated, and their suitability for the implementation of the components of the architecture of the thesis is studied. Subsequently, fuzzy sets are chosen to model dynamic properties of entities. Dempster-Schafer?s combination theory is chosen for aggregating primitive contexts; and Bayesian Networks are chosen to reason about a higher-level context, which is an abstraction of a real-world situation. A Bayesian Composer is implemented to demonstrate the capability of the architecture in dealing with uncertainty, in revising the belief of the Empirical Ambient Knowledge Component, in dealing with the dynamics of primitive contexts and in dynamically defining contextual states. The Composer could be able to reason about the whereabouts of a person in the absence of any localisation sensor. Thermal, relative humidity, light intensity properties of a place as well as time information were employed to model and reason about a place. Consequently, depending on the variety and reliability of the sensors employed, the Composer could be able to discriminate between rooms, corridors, a building, or an outdoor place with different degrees of uncertainty. The Context-Aware E-Pad (CAEP) application is designed and implemented to demonstrate how applications can employ a higher-level context without the need to directly deal with its composition, and how a context rule can be generated by associating the activities (decision events) of a mobile user with the context in which the decision events are produced.
142

Infrastructure mediated sensing

Patel, Shwetak Naran 08 July 2008 (has links)
Ubiquitous computing application developers have limited options for a practical activity and location sensing technology that is easy-to-deploy and cost-effective. In this dissertation, I have developed a class of activity monitoring systems called infrastructure mediated sensing (IMS), which provides a whole-house solution for sensing activity and the location of people and objects. Infrastructure mediated sensing leverages existing home infrastructure (e.g, electrical systems, air conditioning systems, etc.) to mediate the transduction of events. In these systems, infrastructure activity is used as a proxy for a human activity involving the infrastructure. A primary goal of this type of system is to reduce economic, aesthetic, installation, and maintenance barriers to adoption by reducing the cost and complexity of deploying and maintaining the activity sensing hardware. I discuss the design, development, and applications of various IMS-based activity and location sensing technologies that leverage the following existing infrastructures: wireless Bluetooth signals, power lines, and central heating, ventilation, and air conditioning (HVAC) systems. In addition, I show how these technologies facilitate automatic and unobtrusive sensing and data collection for researchers or application developers interested in conducting large-scale in-situ location-based studies in the home.
143

A Distributed Architecture for Computing Context in Mobile Devices

Dargie, Waltenegus 13 June 2006 (has links)
Context-aware computing aims at making mobile devices sensitive to the social and physical settings in which they are used. A necessary requirement to achieve this goal is to enable those devices to establish a shared understanding of the desired settings. Establishing a shared understanding entails the need to manipulate sensed data in order to capture a real world situation wholly, conceptually, and meaningfully. Quite often, however, the data acquired from sensors can be inexact, incomplete, and/or uncertain. Inexact sensing arises mostly due to the inherent limitation of sensors to capture a real world phenomenon precisely. Incompleteness is caused by the absence of a mechanism to capture certain real-world aspects; and uncertainty stems from the lack of knowledge about the reliability of the sensing sources, such as their sensing range, accuracy, and resolution. The thesis identifies a set of criteria for a context-aware system to capture dynamic real-world situations. On the basis of these criteria, a distributed architecture is designed, implemented and tested. The architecture consists of Primitive Context Servers, which abstract the acquisition of primitive contexts from physical sensors; Aggregators, to minimise error caused by inconsistent sensing, and to gather correlated primitive contexts pertaining to a particular entity or situation; a Knowledge Base and an Empirical Ambient Knowledge Component, to model dynamic properties of entities with facts and beliefs; and a Composer, to reason about dynamic real-world situations on the basis of sensed data. Two additional components, namely, the Event Handler and the Rule Organiser, are responsible for dynamically generating context rules by associating decision events ? signifying a user?s activity ? with the context in which those decision events are produced. Context-rules are essential elements with which the behaviour of mobile devices can be controlled and useful services can be provided. Four estimation and recognition schemes, namely, Fuzzy Logic, Hidden Markov Models, Dempster-Schafer Theory of Evidence, and Bayesian Networks, are investigated, and their suitability for the implementation of the components of the architecture of the thesis is studied. Subsequently, fuzzy sets are chosen to model dynamic properties of entities. Dempster-Schafer?s combination theory is chosen for aggregating primitive contexts; and Bayesian Networks are chosen to reason about a higher-level context, which is an abstraction of a real-world situation. A Bayesian Composer is implemented to demonstrate the capability of the architecture in dealing with uncertainty, in revising the belief of the Empirical Ambient Knowledge Component, in dealing with the dynamics of primitive contexts and in dynamically defining contextual states. The Composer could be able to reason about the whereabouts of a person in the absence of any localisation sensor. Thermal, relative humidity, light intensity properties of a place as well as time information were employed to model and reason about a place. Consequently, depending on the variety and reliability of the sensors employed, the Composer could be able to discriminate between rooms, corridors, a building, or an outdoor place with different degrees of uncertainty. The Context-Aware E-Pad (CAEP) application is designed and implemented to demonstrate how applications can employ a higher-level context without the need to directly deal with its composition, and how a context rule can be generated by associating the activities (decision events) of a mobile user with the context in which the decision events are produced.
144

Going Beyond the Desktop Computer with an Attitude

Sokoler, Tomas January 2004 (has links)
This dissertation is based upon the work within a number of research projects, five of which are presented in detail. The work follows the direction of research laid out by the Ubiquitous Computing and Augmented Reality research programs and concerns the broad question of where to go as we seek to take digital technology, and human interactions with this technology, beyond the traditional desktop computer. The work presented takes a design-oriented approach to Human Computer Interaction research. Five prototype systems are presented: Ambient displays for remote awareness, a navigation device providing guidance through tactile cues, a personal device for wastewater plant operators, paper cards enabling control of video playback, and a cell phone that enables you to ‘talk silent’. It is discussed how these prototypes, despite obvious differences, all reflect the same overall attitude towards the role of digital technology. It is an attitude emphasizing that integration of digital technology with everyday human activities means making computational power manifest as part of a larger patchwork of resources. Furthermore, it is an attitude promoting the design of digital technology that leaves the control and initiative with people and their earned ability to take appropriate action when faced with the particularities of the social and physical settings encountered in everyday life beyond the computer screen. In other words, this dissertation brings forward, by using five prototypes as examples, an attitude that encourages us to recognize, embrace, and take advantage of, the fact that human interaction with digital technology takes place, not in a vacuum, but in a rich and diverse world full of many resources for human action other than the digital technology we bring about. / <p>In collaboration with School of Arts and Communication, Malmö University, Sweden.</p>
145

Accessible interaction solution based on confidence for the deployment of pervasive sensitive services in intelligent environments

Vega Barbas, Mario January 2016 (has links)
Services based on the Information and Communications Technologies (ICT) are present more and more in the lives of people. The advancement of ICT in technical and social acceptance terms has led the creation of new models of service provision. These provision models involve further integration with people's activities so that are not only present in their professions or civic space but also in a more intimate areas related to their own identity. So it is now common to find services aware of user's health, their domestic habits, ideology, etc. Therefore, the analysis of existing services must be open out to include other aspects related to the way of being and feeling of their members. This way is possible to ensure both the technical correctness of its features as promoting safe and respectful solutions both of civic rights as the way of being and feeling of its members. From the engineering point of view, the user perspective has historically encompassed under the concept of technological acceptance. Within this field can be interpreted as friendly solutions adapted to users will encourage the acceptance by them. Solution acceptance is desirable although it is difficult to ensure. This difficulty is due to the lack of the number of variables that affect the acceptance of technological solutions and the difficulty of optimizing the known variables. In this thesis it is studied and characterized one of the variables that affect the acceptance of existing services: confidence. Confidence is defined in psychological terms, providing its characterization with the aim of be used in typical methods of engineering. Also different tools are proposed to facilitate the optimization of this confidence in services whose complexity establishes this variable in a basic issue to improve acceptance. Health services deployed in a home have been chosen as working context for this thesis. This scenario presents a number of acceptance restrictions on the technology used to create services and how they manage the acquired user information. It comes to highly sensitive and delocalized services that can affect to the user's perception of the environment, the home, and generate fear or rejection to prevent final adoption as a valid solution. Once defined the generic framework, the main objective of this dissertation is focused on promote the acceptance of new pervasive and personalized health services and their deployment in domestic intelligent environments through a layout that promotes a psychological state of confidence in users. To achieve this goal, a set of results, both conceptual, technological and experimental, have been provided. In particular, it has offered a complete characterization of the feeling of confidence from a viewpoint of engineering and a definition of sensitive or delocalized pervasive service. Furthermore, a method for the inclusion of the Interaction Design discipline in engineering processes of such services through a set of patterns of interaction is offered. Finally, this thesis provides the development of a software architecture to ensure proper deployment of these pervasive sensitive services in intelligent environments in a confident way. Discussion of the results suggests the extension of the deployment model to different services of the Information Society that handle sensitive data both in the context of the digital home and other settings where the user perform everyday activities such as work spaces or schools. The future work lines include the imminent need to apply the results to ongoing developments, within research projects in those the author takes part, and the development of new research lines aimed at creating new spaces and interaction technologies as advanced accessible interfaces, toys of the future, confident visualization systems or security systems based on the condition of the user. / Tjänster baserade på informations- och kommunikationsteknik (IKT) blir allt mer vanligare i människors liv. För att främja acceptansen för IKT i både tekniska och sociala aspekter av människors liv har nya modeller för dessa tjänster skapats. Dessa modeller har en närmare knytning till människors verksamhet så att de inte bara förekommer i deras yrken eller fritid men också i mer intima områden som anknyter till individens egen identitet. Det är nu därför vanligt att hitta tjänster som tar hänsyn till användarens hälsa, vanor, ideologi, etc.  En analys av befintliga tjänster måste inkludera dessa aspekter men även användarnas känsla av identitet och medlemskap. På detta sätt är det möjligt att säkerställa den tekniska riktigheten hos dessa funktioner som i sin tur borgar för säkra och respektfulla lösningar som tar hänsyn till medlemmarnas medborgerliga rättigheter likväl som deras känsla av identitet och medlemskap. Historiskt sett, och ur ett tekniskt perspektiv, har användarperspektivet omfattats under begreppet teknisk acceptans. Inom detta område har användarvänliga lösningar anpassade till användarna själva uppmuntrat acceptans av dem. Acceptans av lösningar är önskvärt även om det är svårt att säkerställa. Denna svårighet beror på avsaknaden av antalet variabler som påverkar acceptansen av tekniska lösningar och svårigheten att optimera de kända variablerna. I denna avhandling studeras och karaktäriseras en av de variabler som påverkar acceptansen av befintliga tjänster: förtroende. Förtroendet definieras i psykologiska termer med syftet att kunna använda termen i typiska metoder för teknik. Det föreslås också olika verktyg för att underlätta optimering av detta förtroende inom tjänstesektorn. Hälso- och sjukvård i hemmet har valts som scenario för denna avhandling. Detta scenario presenterar ett antal restriktioner med avseende på acceptansen av den teknik som används för att skapa tjänster och hur dessa tjänster hanterar den förvärvade användarinformationen. För användaren är situationen mycket känslig och de erbjudna tjänsterna kan påverka användarens uppfattning av miljön och hemmet och/eller generera rädsla eller avsmak för att acceptera lösningen. När den generiska ramen är etablerad är det huvudsakliga syftet med denna avhandling att främja acceptans av nya tjänster för personlig hälsovård och deras användning i hemmet. Detta skall uppnås genom en layout som främjar ett psykologiskt förtroende hos användarna. För att uppnå detta mål har en uppsättning resultat, både begreppsmässiga, tekniska och experimentella, analyserats. Framför allt har en fullständig karaktärisering gjorts av känslan av förtroende från en teknologisk synvinkel och en definition av en känslig och allomfattande tjänst. Dessutom framläggs en metod för införandet av interaktionsdesign i de aktuella tjänsterna genom ett antal interaktionsmönster. Slutligen behandlar denna avhandling utvecklingen av en mjukvaruarkitektur för att säkerställa en korrekt användning av dessa känsliga tjänster. Resultaten pekar på att distributionsmodellen även kan användas för andra tjänster i informationssamhället där användaren utför vardagliga sysslor, såsom i det digitala hemmet eller andra miljöer (t.ex. skolor och arbetsplatser), där känsliga uppgifter hanteras. De framtida arbetsuppgifterna omfattar det överhängande behovet av att tillämpa resultaten på den pågående utvecklingen av forskningsprojekt som författaren är involverad i. Detta omfattar även utveckling av ny forskning som syftar till att skapa ny interaktionsteknik t.ex. avancerade gränssnitt, framtida leksaker, säkra visualiseringssystem eller säkerhetssystem baserat på användarens hälsa/tillstånd. / <p>This PhD research has been conducted under a double PhD agreement degree between the School of Telecommunications Systems and Engineering (ETSIST) at the Technical University of Madrid (UPM) in Spain and the School of Technology and Health (STH) at the Royal Institute of Technology (KTH) in Sweden.</p><p>QC 20160129</p>
146

Οντολογίες στο απανταχού υπολογίζειν και σε κινητές εφαρμογές έχοντας επίγνωση του περιβάλλοντος / Ontologies in context-aware ubiquitous and mobile computing

Χριστοπούλου, Ελένη 14 October 2013 (has links)
Σε αυτή τη διδακτορική διατριβή μελετήσαμε τις δυνατότητες αξιοποίησης των οντολογιών στην αναπαράσταση γνώσης σε συστήματα απανταχού και κινητού υπολογίζειν. / In this thesis we studied the use of ontologies for knowledge representation in ubiquitous and mobile computing.
147

Effective partial ontology mapping in a pervasive computing environment

Kong, Choi-yu., 江采如. January 2004 (has links)
published_or_final_version / abstract / Computer Science and Information Systems / Master / Master of Philosophy
148

Information du Contexte comme une Ressource : Une Approche Orientée Service pour la Sensibilité au Contexte

Romero, Daniel 04 July 2011 (has links) (PDF)
Aujourd'hui, les environnements ubiquitaires font partie de notre vie quotidienne. À la maison, au travail, dans les voitures, dans les hôtels, les supermarchés et autres espaces publiques, nous rencontrons des technologies qui visent à rendre notre vie plus simple et plus facile d'une façon transparente. Durant ces dernières années, le potentiel de ces environnements a été de plus en plus exploité, notamment avec l'avènement et l'utilisation généralisée des smartphones. Ce type de dispositifs permet l'exécution d'applications qui ont la capacité de s'adapter parfaitement à l'état courant de l'environnement. De telles applications, appelées "applications sensibles au contexte", bénéficient de l'information du contexte et des services qui sont présents dans leur environnement pour améliorer et changer automatiquement leur comportement. Toutefois, ces adaptations nécessitent une intégration d'informations qui doit être effectuée en tenant compte de l'hétérogénéité en termes de dispositifs, de plateformes d'exécution, et de protocoles de communication ainsi que la mobilité des applications de sorte que les différentes responsabilités de l'adaptation peuvent être distribuées. Pour faire face à ces défis, et compte tenu des limitations des solutions existantes, nous fournissons deux contributions majeures dans cette dissertation. Tout d'abord nous introduisons l'intergiciel SPACES comme une solution d'intégration des informations contextuelles et ensuite nous définissons le paradigme de "boucles de contrôle ubiquitaires" pour adapter les applications sensibles au contexte. En particulier, dans SPACES, nous définissons un méta-modèle inspiré du style architectural REST (REpresentational State Transfer) pour favoriser l'échange des informations contextuelles en tant que ressources, ce qui représente le fondement de notre approche. Ensuite, nous définissons les connecteurs SPACES pour modulariser les différents concepts et préoccupations identifiés par le méta-modèle. Ces connecteurs sont conçus en utilisant les principes de la programmation orientée composant et ils sont incorporés dans le modèle Service Component Architecture (SCA) pour être utilisés dans différents types d'applications, et ainsi indépendamment des applications sensibles au contexte. Grâce à la définition de SPACES, nous sommes en mesure d'élaborer la seconde contribution de la dissertation--i.e., les boucles de contrôle ubiquitaires. Inspiré par les concepts de l'informatique autonome, les boucles de contrôle offre la flexibilité nécessaire pour intégrer de nouveaux participants dans le processus d'adaptation (par exemple, des applications sensibles au contexte, des services et des systèmes existants) tout en fournissant un support pour la mobilité et l'intégration de nouveaux mécanismes de communication en cas de besoin. Dans le noyau des boucles de contrôle ubiquitaires--i.e., la prise de décision-- nous employons des techniques de programmation par contraintes pour optimiser la configuration courante de l'application en intégrant des critères qui garantissent une meilleure expérience à l'utilisateur final, tels que les coûts associés à l'adaptation, les ressources consommées ou encore la qualité de service offerte par la nouvelle configuration. Enfin, nous validons notre proposition avec trois études de cas: Tout d'abord une politique de Caching or Off-Loading, dans laquelle le comportement de l'application est modifiée lors de l'exécution, ensuite TRACK.ME, une plateforme pour effectuer des expérimentations scientifiques et enfin DIGIHOME, une plateforme pour la création des maisons intelligentes. Ces scénarios démontrent la pertinence de notre approche lorsque différents types de dispositifs, des protocoles et des technologies de mise en œuvre sont impliqués dans le processus d'adaptation.
149

A Framework to Support Opportunistic Groups in Context-Aware Applications

deFreitas, Adrian A. 01 May 2016 (has links)
Context-aware computing utilizes information about users and/or their environments in order to provide relevant information and services. To date, however, most context-aware applications only take advantage of contexts that can either be produced on the device they are running on, or on external devices that are known beforehand. While there are many application domains where sharing context is useful and/or necessary, creating these applications is currently difficult because there is no easy way for devices to share information without 1) explicitly directing them to do so, or 2) through some form of advanced user coordination (e.g., sharing credentials and/or IP addresses, installing and running the same software). This makes these techniques useful when the need to share context is known a priori, but impractical for the one time, opportunistic encounters which make up the majority of users’ lives. To address this problem, this thesis presents the Group Context Framework (GCF), a software framework that allows devices to form groups and share context with minimal prior coordination. GCF lets devices openly discover and request context from each other. The framework then lets devices intelligently and autonomously forms opportunistic groups and work together without requiring either the application developer or the user to know of these devices beforehand. GCF supports use cases where devices only need to share information once or spontaneously. Additionally, the framework provides standardized mechanisms for applications to collect, store, and share context. This lets devices form groups and work together, even when they are performing logically separate tasks (i.e., running different applications). Through the development of GCF, this thesis identifies the conceptual and software abstractions needed to support opportunistic groups in context-aware applications. As part of our design process, we looked at current contextsharing applications, systems, and frameworks, and developed a conceptual model that identifies the most common conditions that cause users/devices to form a group. We then created a framework that supports grouping across this entire model. Through the creation of four prototype systems, we show how the ability to form opportunistic groups of devices can increase users and devices’ access to timely information and services. Finally, we had 20 developers evaluate GCF, and verified that the framework supports a wide range of existing and novel use cases. Collectively, this thesis demonstrates the utility of opportunistic groups in context-aware computing, and highlights the critical challenges that need to be addressed to make opportunistic context sharing both practical and usable in real-world settings. The contributions of this thesis are: 1. A conceptual model, based on an analysis of prior literature, which describes the conditions under which users and/or devices form and work in groups. 2. An implementation of the Group Context Framework, which highlights the software abstractions and architecture needed to support all of the group types identified in our conceptual model. 3. A demonstration of the value of opportunistic groups in context aware computing, through the creation of four major systems and numerous smaller applications. 4. A validation of GCF’s robustness, through an examination of 65 ideas submitted by 20 developers. 5. An examination of the challenges associated with utilizing opportunistic groups in context-aware applications, based on our own experiences using GCF, as well as from issues raised by developers from academia and industry.
150

Supporting human interpretation and analysis of activity captured through overhead video

Romero, Mario January 2009 (has links)
Many disciplines spend considerable resources studying behavior. Tools range from pen-and-paper observation to biometric sensing. A tool's appropriateness depends on the goal and justification of the study, the observable context and feature set of target behaviors, the observers' resources, and the subjects' tolerance to intrusiveness. We present two systems: Viz-A-Vis and Tableau Machine. Viz-A-Vis is an analytical tool appropriate for onsite, continuous, wide-coverage and long-term capture, and for objective, contextual, and detailed analysis of the physical actions of subjects who consent to overhead video observation. Tableau Machine is a creative artifact for the home. It is a long-lasting, continuous, interactive, and abstract Art installation that captures overhead video and visualizes activity to open opportunities for creative interpretation. We focus on overhead video observation because it affords a near one-to-one correspondence between pixels and floor plan locations, naturally framing the activity in its spatial context. Viz-A-Vis is an information visualization interface that renders and manipulates computer vision abstractions. It visualizes the hidden structure of behavior in its spatiotemporal context. We demonstrate the practicality of this approach through two user studies. In the first user study, we show an important search performance boost when compared against standard video playback and against the video cube. Furthermore, we determine a unanimous user choice for overviewing and searching with Viz-A-Vis. In the second study, a domain expert evaluation, we validate a number of real discoveries of insightful environmental behavior patterns by a group of senior architects using Viz-A-Vis. Furthermore, we determine clear influences of Viz-A-Vis over the resulting architectural designs in the study. Tableau Machine is a sensing, interpreting, and painting artificial intelligence. It is an Art installation with a model of perception and personality that continuously and enduringly engages its co-occupants in the home, creating an aura of presence. It perceives the environment through overhead cameras, interprets its perceptions with computational models of behavior, maps its interpretations to generative abstract visual compositions, and renders its compositions through paintings. We validate the goal of opening a space for creative interpretation through a study that included three long-term deployments in real family homes. / <p>QC 20160405</p>

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