711 |
Sistemas de recomendação baseados em contexto físico e socialPEIREIRA, Alysson Bispo 29 June 2016 (has links)
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-07-12T13:47:04Z
No. of bitstreams: 2
license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5)
risethesis.pdf: 1393384 bytes, checksum: f5f2fb9182ce60a9c5d2b0cd95f2893a (MD5) / Made available in DSpace on 2017-07-12T13:47:04Z (GMT). No. of bitstreams: 2
license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5)
risethesis.pdf: 1393384 bytes, checksum: f5f2fb9182ce60a9c5d2b0cd95f2893a (MD5)
Previous issue date: 2016-06-29 / Em meio a grande sobrecarga de dados disponíveis na internet, sistemas de recomendação tornam-se ferramentas indispensáveis para auxiliar usuários no encontro de itens ou conteúdos relevantes. Diversas técnicas de recomendação são aplicadas em diversos tipos de domínios diferentes. Seja na recomendação de filmes, música, amigos, lugares ou notícias, sistemas de recomendação exploram diversas informações disponíveis para aprender as preferências dos usuários e promover recomendações úteis. Uma das estratégias mais utilizadas é a de filtragem colaborativa. A qualidade dessa estratégia depende da quantidade de avaliações disponíveis e da qualidade do algoritmo utilizado para predição de avaliação. Estudos recentes demonstram que informações provenientes de redes sociais podem ser muito úteis para aumentar a precisão das recomendações. Assim como acontece no mundo real, no mundo virtual usuários buscam recomendações e conselhos de amigos antes de comprar um item ou consumir algum serviço, informações desse tipo podem ser úteis para definição do contexto social da recomendação. Além do social, informações físicas e temporais passaram a ser utilizadas para definição do contexto físico de cada recomendação. A companhia, a localização e as condições climáticas são bons exemplos de elementos físicos que levam um usuário a preferir certos itens. Um processo de recomendação que não leve em consideração elementos contextuais pode fazer com que o usuário tenha uma péssima experiência consumindo determina do item recomendado equivocadamente. Esta dissertação tem como objetivo investigar técnicas de filtragem colaborativa que utilizam contexto a fim de realizar recomendações que auxiliem usuários no encontro de itens relevantes. Nesse tipo de técnica, um sistema de recomendação base é utilizando para fornecer recomendações para o usuário alvo. Em seguida, são filtrados apenas os itens considerados relevantes para contextos previamente identificados nas preferências do usuário alvo. As técnicas implementadas foram aplicadas em dois experimentos com duas bases de dados de domínios diferentes: uma base composta por eventos e outra por filmes. Na recomendação de eventos, investigamos o uso de contextos físicos (i.e., tempo e local) e de contextos sociais (i.e., amigos na rede social) associados aos itens sugeridos aos usuários. Na recomendação de filmes, por sua vez, investigamos novamente o uso de contexto social. A partir da aplicação de pós-filtragem em três algoritmos de filtragem colaborativa usados como base, foi possível recomendar itens de forma mais precisa, como demonstrado nos experimentos realizados. / The overload of data available on the internet makes recommendation systems become indispensable tools to assist users in meeting items or relevant content. Several recommendation techniques were has been userd in many different types of domains. Those systems can recommend movies, music, friends, places or news; recommender systems can exploit different information available to learn preferences of users and promote more useful recommendations. The collaborative filtering strategy is one of the most used. The quality of this technique depends on the number of available ratings and the algorithm used to predict. Recent studies show that information from social networks can be very useful to increase the accuracy recommendations. Just as in the real world, the virtual world users ask recommendations and advice from friends before buying an item or consume a service. Furthermore, the context of each rating may be crucial for the definition of new ratings. Location, date time and weather conditions are good examples of useful elements to define what should be the best items to recommend for some user. A recommendation process that does not respect those elements can provide a user a bad experience. This dissertation investigates collaborative filtering techniques based on context, and more specifically techniques based on post-filtering. First, a recommendation system was used to provide recommendations for a specific user. Then, only relevant items according to context preferences for the target user will be recommended. The techniques implemented was applied in two case studies with two different domains databases: one base composed of events and another of movies. In the event of recommendation, we investigated the use of physical contexts (i.e., time and place) and social contexts (i.e., friends in the social network) associated with items suggested to users. On the recommendation of movies, in turn, again we investigated the use of social context. From the application of post-filtering in three collaborative filtering algorithms used as a baseline, it was possible to recommend items more accurately, as demonstrated in the experiments.
|
712 |
Extração de informação contextual utilizando mineração de textos para sistemas de recomendação sensíveis ao contexto / Contextual information extraction using text mining for recommendation systems context sensitiveCamila Vaccari Sundermann 20 March 2015 (has links)
Com a grande variedade de produtos e serviços disponíveis na Web, os usuários possuem, em geral, muita liberdade de escolha, o que poderia ser considerado uma vantagem se não fosse pela dificuldade encontrada em escolher o produto ou serviço que mais atenda a suas necessidades dentro do vasto conjunto de opções disponíveis. Sistemas de recomendação são sistemas que têm como objetivo auxiliar esses usuários a identificarem itens de interesse em um conjunto de opções. A maioria das abordagens de sistemas de recomendação foca em recomendar itens mais relevantes para usuários individuais, não levando em consideração o contexto dos usuários. Porém, em muitas aplicações é importante também considerar informações contextuais para fazer as recomendações. Por exemplo, um usuário pode desejar assistir um filme com a sua namorada no sábado à noite ou com os seus amigos durante um dia de semana, e uma locadora de filmes na Web pode recomendar diferentes tipos de filmes para este usuário dependendo do contexto no qual este se encontra. Um grande desafio para o uso de sistemas de recomendação sensíveis ao contexto é a falta de métodos para aquisição automática de informação contextual para estes sistemas. Diante desse cenário, neste trabalho é proposto um método para extrair informações contextuais do conteúdo de páginas Web que consiste em construir hierarquias de tópicos do conteúdo textual das páginas considerando, além da bag-of-words tradicional (informação técnica), também informações mais valiosas dos textos como entidades nomeadas e termos do domínio (informação privilegiada). Os tópicos extraídos das hierarquias das páginas Web são utilizados como informações de contexto em sistemas de recomendação sensíveis ao contexto. Neste trabalho foram realizados experimentos para avaliação do contexto extraído pelo método proposto em que foram considerados dois baselines: um sistema de recomendação que não considera informação de contexto e um método da literatura de extração de contexto implementado e adaptado para este mestrado. Além disso, foram utilizadas duas bases de dados. Os resultados obtidos foram, de forma geral, muito bons apresentando ganhos significativos sobre o baseline sem contexto. Com relação ao baseline que extrai informação contextual, o método proposto se mostrou equivalente ou melhor que o mesmo. / With the wide variety of products and services available on the web, it is difficult for users to choose the option that most meets their needs. In order to reduce or even eliminate this difficulty, recommender systems have emerged. A recommender system is used in various fields to recommend items of interest to users. Most recommender approaches focus only on users and items to make the recommendations. However, in many applications it is also important to incorporate contextual information into the recommendation process. For example, a user may want to watch a movie with his girlfriend on Saturday night or with his friends during a weekday, and a video store on the Web can recommend different types of movies for this user depending on his context. Although the use of contextual information by recommendation systems has received great focus in recent years, there is a lack of automatic methods to obtain such information for context-aware recommender systems. For this reason, the acquisition of contextual information is a research area that needs to be better explored. In this scenario, this work proposes a method to extract contextual information of Web page content. This method builds topic hierarchies of the pages textual content considering, besides the traditional bag-of-words, valuable information of texts as named entities and domain terms (privileged information). The topics extracted from the hierarchies are used as contextual information in context-aware recommender systems. By using two databases, experiments were conducted to evaluate the contextual information extracted by the proposed method. Two baselines were considered: a recommendation system that does not use contextual information (IBCF) and a method proposed in literature to extract contextual information (\\methodological\" baseline), adapted for this research. The results are, in general, very good and show significant gains over the baseline without context. Regarding the \"methodological\" baseline, the proposed method is equivalent to or better than this baseline.
|
713 |
Generic Decentralized Self-Adaptive Context-Aware Architecture Model / Generic Decentralized Self-Adaptive Context-Aware Architecture ModelKazzaz, M. Mohanned Unknown Date (has links)
Vývoj v informačním systému neustále zvyšuje nároky na účinnou, efektivní a adaptivní spolupráci mezi komponenty systému, aby se vyrovnal se změnami v systému a zaručil tak nejlepší výkon. K dosažení těchto požadavků byly zavedeny dva hlavní přístupy. Přístup k adaptaci umožňuje informačnímu systému přizpůsobit se změnám v kontextu informací systému a jeho okolního prostředí na základě adaptační strategie. Přístup ke zvyšování informovanosti zase napomáhá sledovat informace o kontextu a rozpoznat změny, které mohou proces adaptace vyvolat. V této práci představujeme obecný kontextově orientovaný model vlastní adaptivní architektury pro podporu softwarového systému s adaptačními funkcemi, které zaručují dostupnost systému, provozní podmínky a výkon. Navíc poskytujeme dvě případové studie v reálném životě jako důkaz konceptu použitelnosti našeho navrhovaného adaptačního přístupu.
|
714 |
Gestion du contexte pour des applications mobiles dédiées aux transportsPopovici, Dana 10 December 2012 (has links)
De nos jours, la façon d’utiliser les applications mobiles dans le domaine des transports offre de nouveaux défis liés aux spécificités de l’environnement, comme la forte mobilité des terminaux, leur répartition, ou encore le réseau instable de communication. La plupart des applications existantes ont des contraintes de fonctionnement qui les rendent inadaptées si les conditions d’exécution évoluent rapidement. Cela rend intéressant l’utilisation d’un cadre unifié de conception et d’exécution, capable de gérer ces applications. Nos travaux portent, dans un premier temps, sur une étude des applications mobiles et de leur comportement, en fonction du contexte d’exécution. Nous considérons le cas des applications dédiées aux transports, conçues pour accompagner et assister un usager dans son déplacement (navigation, sécurité routière, applications des moyens de transports, etc.). Nous identifions les éléments du contexte propres aux applications fortement mobiles et les modélisons. Dans un second temps, nous proposons un cadre dynamique et sensible au contexte, permettant le déploiement de nouveaux services « à la volée » ainsi que leur adaptation pour une meilleure utilisation des ressources dans des milieux très évolutifs. Nous nous focalisons sur le côté réactif, permettant d’adapter le comportement des applications à leurs nouvelles conditions d’utilisation. Les applications sont décomposées en services de base avec un couplage lâche pour une plus grande flexibilité. Nous utilisons une architecture orientée service, qui permet la réutilisation des services communs à plusieurs applications mais aussi la gestion du contexte au travers de services équivalents mais capables de fonctionner dans des conditions différentes.Nous montrons, grâce au prototype de notre plateforme CATS (Context-Aware Transportation Services), d’abord la faisabilité d’une plateforme à services sur des terminaux portables. Nous testons ensuite plusieurs scénarios afin de démontrer la réactivité des adaptations aux changements de contexte. Dans cette thèse nous proposons une vue d’ensemble sur la création et la gestion des applications sensibles au contexte pour le domaine des transports. Le but de notre démarche est d’assurer le bon fonctionnement de l’ensemble des applications d’un utilisateur, malgré les changements dynamiques du contexte. / The use of mobile applications in the transportation domain raises a multitude ofchallenges, related to the specific execution environment: highly mobile and distributed devices, unstable communication networks, etc. Most of the existing applications are not flexible enough to cope with the rapidly changing environment. It would be interesting to provide a unified frame for the design and execution of such applications, offering management capabilities as well. We propose a study of the mobile applications and their behavior in relation with thecontext. We consider a certain type of applications, designed to accompany and assist users on the move (navigation, traffic security, applications related to a means of transport, etc.). We identify the context elements which are characteristic to highly mobile applications and we propose a context model for the transportation domain. In order to handle multiple applications at a time, we propose a dynamic and contextaware framework, capable of deploying services “on the fly”. We consider applications built through the assembly of services, allowing them to adapt to the execution environment and make the best use of the available resources. We focus on the reaction of the applications to the changes in the environment. Applications are built of services and thus benefit from loose coupling, allowing them to be flexible. A service oriented architecture brings further advantages, notably that services can be shared between applications and that a service can have multiple implementations. We manage the adaptation to new conditions of use through equivalent services built for different context situations. The framework that we have proposed, called CATS (Context-Aware Transportation Services), has been tested thanks to a prototype. We were able to prove the feasibility of the framework as well as evaluate several testing scenarios, showing the reactivity of the applications to context changes. This work proposes a complete view of the design and management of context-aware applications for the transport domain. Our goal is to enhance user experience by ensuring the well functioning of his/her applications despite the ever changing context.
|
715 |
The value of context awareness within information technology audit and governanceLe Roux, Theo January 2020 (has links)
Thesis (MTech (Business Information Systems))--Cape Peninsula University of Technology, 2020 / A shared common understanding or context awareness (CA) of IT Audit and Governance among all the internal stakeholders of a business remains an important factor. This context awareness is needed between the business itself, the IT department, and the Audit and Risk functions of the business.
The research problem states that there is a lack of shared context awareness among all stakeholders when conducting IT audits and implementing IT Governance. To answer the research questions, a case study research strategy was followed using an International Services Group of companies operating from South Africa. The case study offered a diverse group of companies and vast experience in the South African Services, Trading, and Distribution sector. The diversity of this group of companies made it a perfect candidate for understanding context and the value of context in IT when conducting IT audits.
The following research questions were asked: i) What are the factors affecting a shared context understanding among the stakeholders when conducting IT audits and implementing IT Governance? ii) How can a shared context understanding among stakeholders be achieved when conducting IT audits and implementing IT Governance?
The aim of the study was to explore the value of context awareness within IT Audit and Governance in order to identify the value of shared context understanding.
Data collection was done by means of interviews using semi-structured questionnaires and an interview guide. Qualitative data analysis techniques were adopted for this research. The conclusion of the study highlights the importance of a collective understanding of the business’s context in order to obtain alignment in business, IT, and Audit. It refers to the same or a similar understanding of the business processes; this takes time and is unique on all levels.
|
716 |
Mockup - Kontextmedvetet resestöd vid oväntade trafikstörningar i kollektivtrafiken / Mockup - Context-aware travel assistance at unexpected traffic disruptions in public transportSteen, Arvid, Zreim, Ali January 2022 (has links)
In this paper, a mockup application is created to examine how the commuter’s context, with a focus on the train the commuter is on, can be used to suggest individual alternative travel routes to support the commuter in arriving at the requested destination based on minimal delay with consideration of an uncertainty factor. Based on investigations of various travel applications, four different concepts are created that are used in a user survey where commuters can answer questions regarding, alternative travel routes, uncertainty factors and guidance to the requested destination. The purpose of this paper is to investigate how context can be used in a travel application and which information is relevant to the commuter. Based on the context the commuter will receive proposed alternative travel routes in the event of disruptions in public transport to simplify traveling by public transport, which in turn can attract more people to travel by public transport. A concluded user survey consisting of 47 respondents show the user perspective on how a commuter’s context can be used to recommend alternative routes, which contexts are relevant to provide better support for the commuter and which type of information the commuter thinks would best support them / I detta arbete skapas en mockup-applikation för att undersöka hur resenärens kontext, medfokus på tåget resenären befinner sig på, kan användas för att föreslå individanpassade alternativa resvägar som stöd till resenären för att ankomma till begärd destination medminimal försening och osäkerhetsfaktor i åtanke. Utifrån undersökningar av olika reseapplikationer skapas fyra olika koncept som används i en enkätundersökning där resenärer får besvara frågor angående bland annat, alternativa resvägar, osäkerhetsfaktorer och vägledning till begärd destination. Syftet med arbetet är att undersöka hur kontext kan användas i en reseapplikation och vilken information som är relevant för resenären. Utifrån detta ska resenären få förslag på alternativa resvägar vid störningar i kollektivtrafiken för att ge känslan av trygghet och kontroll, samt förenkla kollektivt resande vilket i sin tur kan locka till att fler väljer att resa kollektivt. En genomförd enkätundersökning bestående av 47 respondenter visar användarperspektivet på hur resenärens kontext kan användas för att rekommendera alternativa resvägar, vilka kontexter som är relevanta för att bidra med bättre stöd för resenären samt vilken typ av information anses stödja resenären bäst.
|
717 |
Occupancy Sensor System : For Context-aware ComputingHübinette, Daniel January 2007 (has links)
This masters thesis project, "Occupancy Sensor System", was conducted at Kungliga Tekniska Högskolan (KTH), Stockholm, Sweden, during the period 2007-04-24 – 2007-12-17. The goal of the project was to design an occupancy sensor system that determines if there exists more than one person in a defined region. The output of this system is for use in a context-aware system at the KTH Center for Wireless Systems (Wireless@KTH). The system is important because there is a need for specific input to context-aware systems concerning occupancy of spaces and because this thesis has focused on a problem that enables new complex and interesting services. Additionally, the specific problem of determining not only occupancy, but if this occupancy is zero, one, many has not been widely examined previously. The significance of zero occupants indicating an empty room has already been recognized as having economic and environmental value in terms of heating, ventilating, air-conditioning, and lighting. However, there has not been an effort to differentiate between a person being alone or if more than one person is present. A context-aware system might be able to use this later information to infer that a meeting is taking place in a meeting room, a class taking place in a classroom or that an individual is alone in a conference room, class room, etc. Thus enabling context-aware services to change their behavior based upon the differences in these situations. An occupancy sensor system prototype was designed to monitor a boundary by using a thermal detector, gumstix computer, an analog to digital converter prototype board, laptop computer, and a context broker. The testing and evaluation of the system, proved it to be sound. However, there are still further improvements and tests to be made. These improvements include: dynamic configuration of the system, communication between the different system entities, detection algorithms, and code improvements. Tests measuring accuracy of a detection algorithm and determining optimal detector placement need to be performed. The next step is to design applications that use the context information provided from the occupancy sensor system and expand the system to use multiple detectors. / Examensarbetet "Occupancy Sensor System" genomfördes på Kungliga Tekniska Högskolan (KTH), Stockholm, Sverige, under perioden 2007-04-24 – 2007-12-17. Målet med examensarbetet var att designa ett sensorsystem, som avgör om ett rum är befolkat med fler än en person i ett definierat område. Resultatet av detta system är till för användning i ett kontextmedvetet system som finns i KTH Center for Wireless Systems (Wireless@KTH). Systemet är viktigt eftersom det finns ett behov för specifik input till kontextmedvetna system som berör befolkning av rum och eftersom detta examensarbete har fokuserat på ett problem som möjliggör nya komplexa och intressanta tjänster. Dessutom har det inte tidigare undersökts i vidare bemärkelse hur man kan avgöra om ett rum befolkats av noll, en eller flera personer. Betydelsen av att ett rum är obefolkat har redan ansetts ha ekonomiskt och miljöbetingat värde vad gäller uppvärming, ventilation, luftkonditionering och belysning. Däremot har det inte gjorts ansträngningar att differentiera mellan att en ensam person eller flera är närvarande. Ett kontextmedvetet system skulle kunna använda den senare nämnda informationen för att dra slutsatsen att ett möte pågår i ett mötesrum, en lektion är igång i ett klassrum o.s.v. Detta möjliggör i sin tur för kontextmedvetna tjänster att ändra på sina beteenden baserat på skillnaderna i dessa situationer. En prototyp utvecklades för att övervaka en gräns genom användningen av en termisk detektor, gumstixdator, analog till digital signalkonverterare, bärbar dator och en context broker (kontextförmedlare). Testningar och utvärderingar av systemet visade att systemet var dugligt. Flera förbättringar och tester behöver dock göras i framtiden. Dessa förbättringar inkluderar: dynamisk konfiguration av systemet, kommunikation mellan de olika systementiteterna, detektionsalgoritmer och kodförbättringar. Återstående tester inkluderar mätning av en detektionsalgoritms tillförlitlighet samt optimal placering av detektorer. Nästa steg är att utveckla applikationer som använder kontextinformationen från systemet samt att utveckla systemet till att kunna använda flera detektorer.
|
718 |
Single fathers' experience of fatherhoodVan Zyl, Izelle 08 April 2010 (has links)
In recent years various factors have contributed to the dissolution of the traditional family and the subsequent emergence of alternative family systems like the single parent family. Single parent families have become a reality in our society, a fact reflected by statistics which indicate an increase in the occurrence of single parent families over the last couple of years. However, the single parent family is still mostly perceived as consisting of the mother and her children, rather than the father and his children. Research narratives seem to support the single-parenthood-equals-single-motherhood plot in that there is an abundance of single parent accounts in the literature that mostly tell the stories of single mothers. Thus, fathers who find themselves in the position of single father seem to be marginalised in society and stories regarding their experiences are few and far between. The aim of this project was to explore and describe how single fathers in South Africa experience fatherhood by focussing on their personal narratives. Therefore the research inquiry for this project took the form of a narrative inquiry which provides a way to understand people’s experiences by privileging their stories. The researcher conducted unstructured interviews with participants to produce languaged data which were analysed using a narrative analysis strategy. A narrative analysis aims to investigate not merely the content of the story, but rather the story itself and the way in which it is told within a specific cultural and historical context. Hopefully, in the telling, listening and retelling of their stories these fathers’ voices will become more pronounced in the research narratives and thus contribute to the body of knowledge pertaining to single fatherhood. Copyright / Dissertation (MA)--University of Pretoria, 2008. / Psychology / Unrestricted
|
719 |
Personalised assistance for fuel-efficient drivingGilman, Ekaterina, Keskinarkaus, Anja, Tamminen, Satu, Pirttikangas, Susanna, Röning, Juha, Riekki, Jukka 18 November 2020 (has links)
Recent advances in technology are changing the way how everyday activities are performed. Technologies in the traffic domain provide diverse instruments of gathering and analysing data for more fuel-efficient, safe, and convenient travelling for both drivers and passengers. In this article, we propose a reference architecture for a context-aware driving assistant system. Moreover, we exemplify this architecture with a real prototype of a driving assistance system called Driving coach. This prototype collects, fuses and analyses diverse information, like digital map, weather, traffic situation, as well as vehicle information to provide drivers in-depth information regarding their previous trip along with personalised hints to improve their fuel-efficient driving in the future. The Driving coach system monitors its own performance, as well as driver feedback to correct itself to serve the driver more appropriately.
|
720 |
Context dependency analysis in ubiquitous computing / Analyse de dépendance contexte dans ubiquitous computingBaloch, Raheel Ali 17 February 2012 (has links)
Pour fournir aux utilisateurs des services personnalisés d'adaptation en utilisant uniquement les ressources informatiques accessibles dans un environnement de cloud computing, les applications contexte, conscients besoin d'assimiler à la fois le contexte accessible et dérivés, c'est à dire une combinaison de plus d'un senti données et d'informations dans l'environnement. Contexte des données de dépendance, la dépendance qui se pose entre le contexte des données du producteur et du consommateur, peut se présenter dans un système en raison de nombreuses raisons. Mais comme le nombre de dépendances de contexte pour une augmentation des services, la plus complexe, le système devient à gérer. La thèse aborde les questions de la façon d'identifier les dépendances de contexte, représentent des dépendances de contexte tels, puis les réduire dans un système. Dans la première partie de la thèse, nous présentons deux approches efficaces pour déterminer les relations de dépendance entre les différents services du contexte dans l'environnement informatique ubiquitaire pour aider à mieux analyser les services omniprésents. Une approche est basée sur la théorie des graphes, et nous avons utilisé le tri topologique pour déterminer les dépendances de contexte. La deuxième approche est basée sur la résolution des réseaux de contraintes qui détermine si une entité est affectée lorsque l'état d'une certaine entité autre a changé son état, c.-à-détermination de la nature dynamique de la dépendance contexte. Dans la deuxième partie de la thèse, nous présentons un mode de représentation des dépendances de contexte au sein d'un système. Notre modèle qui représente les dépendances de contexte est basé sur la théorie des ensembles et la logique des prédicats du premier ordre. Le modèle de représentation contexte de dépendance représente également d'autres sources pour l'acquisition de contexte qui peuvent être utilisés dans une affaire dans laquelle les producteurs contexte privilégiées ne sont pas disponibles pour desservir le contexte souhaité pour le consommateur un contexte pertinent, pas plus. En outre, nous essayons de réduire les dépendances de contexte en présentant l'idée du contexte de profil, qui est basé sur la proposition d'un cadre ouvert pour l'acquisition de contexte, la gestion et la distribution. Cette approche heuristique est basée sur l'idée d'utiliser les nœuds mobiles dans un réseau ad hoc avec superposition de plus de ressources que le producteur lui-même contexte pour stocker diverses informations contextuelles sous la bannière du contexte profil, et en outre, fournir le contexte profil au lieu de chaque contexte individuellement sur la base sur les requêtes des nœuds reçoivent des consommateurs contexte. Réunissant les informations de contexte et de mises à jour de contexte à partir de diverses sources, le soutien aux décisions contexte, conscients peut être mis en œuvre efficacement dans un environnement mobile en s'attaquant aux problèmes de dépendance en utilisant le contexte contexte profil / To provide users with personalized adaptive services only using the accessible computing resources in a cloud environment, context aware applications need to assimilate both the accessed and derived context, i.e. a combination of more than one sensed data and information in the environment. Context data dependency, dependency that arises between the context data producer and consumer, may get introduced in a system due to numerous reasons. But as the number of context dependencies for a service increases, the more complex the system becomes to manage. The thesis addresses issues of how to identify context dependencies, represent such context dependencies and then reduce them in a system. In the first part of the thesis, we present two efficient approaches to determine context dependency relations among various services in ubiquitous computing environment to help better analyse the pervasive services. One approach is based on graph theory, and we have used the topological sort to determine the context dependencies. The second approach is based on solving constraint networks which determines whether an entity is affected when the state of a certain other entity has its state changed, i.e. determining the dynamic nature of context dependency. In the second part of the thesis, we present a mode for representation of context dependencies within a system. Our model that represents context dependencies is based on set theory and first-order predicate logic. The context dependency representation model also represents alternative sources for context acquisition that can be utilized in a case in which the preferred context producers are not available to service the desired context to the relevant context consumer any more. Further, we try to reduce the context dependencies by presenting the idea of profile context, which is based on the proposal of an open framework for context acquisition, management and distribution. This heuristic approach is based on the idea of utilizing mobile nodes in an ad hoc overlay network with more resources than the context producer itself to store various contextual information under the banner of profile context, and further, provide profile context instead of each context individually based on the queries the nodes receive from the context consumers. Bringing together the context information and context updates from various sources, support for context aware decisions can be implemented efficiently in a mobile environment by addressing the issues of context dependency using profile context
|
Page generated in 0.0587 seconds