Au cours des dernières décennies, Internet a connu une révolution et une croissance exponentielle.A la suite de cette croissance, un grand nombre de services web et d’applications ont émergé pour répondre aux différents besoins des consommateurs. En même temps, l’industrie du réseau mobile est devenue omniprésente, ce qui rend la plupart des utilisateurs inséparables de leurs terminaux mobiles. La combinaison de la technologie mobile et des services web fournit un nouveau paradigme appelé services web mobiles. Ainsi, la consommation des services web a` partir des appareils mobiles émerge en proposant plusieurs facilites´ aux utilisateurs et en imposant plus de manipulations de ces services.En effet, afin que les utilisateurs trouvent des services répondant a` leurs besoins, un mécanisme de découverte est nécessaire, par ailleurs, les demandes sont devenues non seulement plus complexes mais aussi plus dynamiques, un service unique qui offre une fonctionnalité simple et primitive est devenu insuffisant pour satisfaire les besoins et les exigences complexes. Par conséquent, la combinaison de multiples services pour fournir un service composite est de plus en plus utilisée demandée. Nous parlons ainsi des mécanismes de découverte et de composition des services web mobiles. Ces deux paradigmes sont mutuellement liés et complémentaires.La découverte et la composition des services web dans un environnement mobile soulèvent plusieurs défis qui n’existent pas dans un environnement classique (non mobile). Parmi ces défis se trouve les contraintes limitées de l’appareil mobile, appelé dans ce travail contexte statique, ainsi que le changement de contexte qui est duˆ principalement a` la mobilité du dispositif, appelé contexte dynamique.Ainsi, l’objet de la présente thèse est de proposer un Framework de composition de services web mobile englobant deux approches complémentaires. Une première approche proposée est consacrée a` la découverte des services web mobiles appelée MobiDisc et une deuxième qui propose une solution a` la problématique de composition dans un contexte dynamique. Notre première approche exploite le contexte statique avec les propriétés de QoS et les préférences´ utilisateurs dans les descriptions sémantiques des services et de la requête utilisateur afin d’augmenter l’exactitude du processus de découverte. Quand a` l’approche de composition, elle met l’accent sur le contexte dynamique qui peut modifier le résultat de la composition. L’objectif est de déterminer la sensibilité des services au contexte dynamique et de générer des plans de composition pour l’utilisateur tries´ selon leurs valeurs de sensibilité globale lui permettant de choisir la meilleure composition. / Over the last two decades, Internet has grown exponentially. causing the emergence of web ser-vices and applications that meet the different needs of the consumers. During the same period, the mobile network industry has become ubiquitous, making most users inseparable from their mobile devices. So the combination of mobile technology and web services provides a new paradigm named mobile web services. Thus, the consumption of web services from mobile devices emerges by offering several facilities to users and requiring greater manipulation of these services such as discovery, composition and execution.Indeed, in order for users to find services that meet their requirements, a discovery mechanism is needed. Since requests have become not only more complex, but also more dynamic, a single service that offers simple and primitive functionality has become insufficient to satisfy the complex requirements. Therefore, the combination of multiple services to provide a composite service is more and more requested. We talk about mobile web service discovery and composition. These two paradigms are mutually linked and complementary.The discovery and composition of web services in a mobile environment raise several challenges that do not exist in a traditional (non-mobile) environment. Among these challenges are the limited constraints of the mobile device, called in this work static context, as well as the change of context which is due mainly to the mobility of the device which called dynamic context.In this thesis we propose a framework for the composition of mobile web services encompassing two complementary approaches. A first proposed approach called MobiDisc, speaking about the discovery of mobile web services and a second that proposes a solution to the problem of composition in a dynamic context. Our first approach uses the static context with QoS properties and user preferences in the semantic descriptions of services and the user query to increase the accuracy of the discovery process. As for the second compositional approach, it focuses on the dynamic context that can modify the composition result. The objective is to determine the sensitivity of the services to the dynamic context and to generate composition plans to the user ordered according to a sensitivity value.

O codificador aritmético binário adaptativo ao contexto adotado (CABAC – Context-based Adaptive Binary Arithmetic Coding) pelo padrão H.264/AVC a partir de perfil Main é o estado-da-arte em termos de eficiência de taxa de bits. Entretanto, o CABAC ocupa 9.6% do tempo total de processamento e seu throughput é limitado pelas dependências de dados no nível de bit (LIN, 2010). Logo, atingir os requisitos de desempenho em tempo real nos níveis mais altos do padrão H.264/AVC se torna uma tarefa árdua em software, sendo necesário então, a aceleração do CABAC através de implementações em hardware. As arquiteturas de hardware encontradas na literatura para o CABAC focam no Codificador Aritmético Binário (BAE - Binary Arithmetic Encoder) enquanto que a Binarização e Modelagem de Contextos (BCM – Binarization and Context Modeling) fica em segundo plano ou nem é apresentada. O BCM e o BAE juntos constituem o CABAC. Esta dissertação descreve detalhadamente o conjunto de algoritmos que compõem o BCM do padrão H.264/AVC. Em seguida, o projeto de uma arquitetura de hardware específica para o BCM é apresentada. A solução proposta é descrita em VHDL e os resultados de síntese mostram que a arquitetura alcança desempenho suficiente, em FPGA e ASIC, para processar vídeos no nível 5 do padrão H.264/AVC. A arquitetura proposta é 13,3% mais rápida e igualmente eficiente em área que os melhores trabalhos relacionados nestes quesitos. / Context-based Adaptive Binary Arithmetic Coding (CABAC) adopted in the H.264/AVC main profile is the state-of-art in terms of bit-rate efficiency. However, CABAC takes 9.6% of the total encoding time and its throughput is limited by bit-level data dependency (LIN, 2010). Moreover, meeting real-time requirement for a pure software CABAC encoder is difficult at the highest levels of the H.264/AVC standard. Hence, speeding up the CABAC by hardware implementation is required. The CABAC hardware architectures found in the literature focus on the Binary Arithmetic Encoder (BAE), while the Binarization and Context Modeling (BCM) is a secondary issue or even absent in the literature. Integrated, the BCM and the BAE constitute the CABAC. This dissertation presents the set of algorithms that describe the BCM of the H.264/AVC standard. Then, a novel hardware architecture design for the BCM is presented. The proposed design is described in VHDL and the synthesis results show that the proposed architecture reaches sufficiently high performance in FPGA and ASIC to process videos in real-time at the level 5 of H.264/AVC standard. The proposed design is 13.3% faster than the best works in these items, while being equally efficient in area.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-08-08T13:11:15Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) tese.pdf: 4855618 bytes, checksum: 717d268b142705bdc8ce106731a257db (MD5) / Made available in DSpace on 2016-08-08T13:11:15Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) tese.pdf: 4855618 bytes, checksum: 717d268b142705bdc8ce106731a257db (MD5) Previous issue date: 2016-03-28 / CAPEs / Proof assistants are software-based tools that are used in the mechanization of proof construction and validation in mathematics and computer science, and also in certified program development. Different such tools are being increasingly used in order to accelerate and simplify proof checking, and the Coq proof assistant is one of the most known and used. Language and automata theory is a well-established area of mathematics, relevant to computer science foundations and information technology. In particular, context-free language theory is of fundamental importance in the analysis, design and implementation of computer programming languages. This work describes a formalization effort, using the Coq proof assistant, of fundamental results of the classical theory of context-free grammars and languages. These include closure properties (union, concatenation and Kleene star), grammar simplification (elimination of useless symbols, inaccessible symbols, empty rules and unit rules), the existence of a Chomsky Normal Form for context-free grammars and the Pumping Lemma for context-free languages. To achieve this, several steps had to be fulfilled, including (i) understanding of the characteristics, importance and benefits of mathematical formalization, specially in computer science, (ii) familiarization with the underlying mathematical theories used in proof assistants, (iii) familiarization with the Coq proof assistant, (iv) review of the strategies used in the informal proofs of the main results of the context-free language theory and finally (iv) selection and adequation of the representation and proof strategies adopted in order the achieve the desired objectives. The result is an important set of libraries covering the main results of context-free language theory, with more than 500 lemmas and theorems fully proved and checked. This is probably the most comprehensive formalization of the classical context-free language theory in the Coq proof assistant done to the present date, and includes the remarkable result that is the formalization of the Pumping Lemma for context-free languages. The perspectives for the further development of this work are diverse and can be grouped in three different areas: inclusion of new devices and results, code extraction and general enhancements of its libraries. / Assistentes de prova são ferramentas de software que são usadas na mecanização da construção e da validação de provas na matemática e na ciência da computação, e também no desenvolvimento de programas certificados. Diferentes ferramentas estão sendo usadas de forma cada vez mais frequente para acelerar e simplificar a verificação de provas, e o assistente de provas Coq é uma das mais conhecidas e utilizadas. A teoria de linguagens e de autômatos é uma área bem estabelecida da matemática, com relevância para os fundamentos da ciência da computação e a tecnologia da informação. Em particular, a teoria das linguagens livres de contexto é de fundamental importância na análise, no projeto e na implementação de linguagens de programação de computadores. Este trabalho descreve um esforço de formalização, usando o assistente de provas Coq, de resultados fundamentais da teoria clássica das gramáticas e linguagens livres de contexto. Estes incluem propriedades de fechamento (união, concatenação e estrela de Kleene), simplificação gramatical (eliminação de símbolos inúteis, de símbolos inacessíveis, de regras vazias e de regras unitárias), a existência da Forma Normal de Chomsky para gramáticas livres de contexto e o Lema do Bombeamento para linguagens livres de contexto. Para alcançar estes resultados, diversas etapas precisaram ser cumpridas, incluindo (i) o entendimento das características, da importância e dos benefícios da formalização matemática, especialmente na ciência da computação, (ii) a familiarização com as teorias matemáticas fundamentais utilizadas pelos assistentes de provas, (iii) a familiarização com o assistente de provas Coq, (iv) a revisão das estratégias usadas nas provas informais dos principais resultados da teoria das linguagens livres de contexto e, finalmente, (v) a seleção e adequação das estratégias de representação e prova adotadas para permitir o alcance dos resultados pretendidos. O resultado é um importante conjunto de bibliotecas cobrindo os principais resultados da teoria das linguagens livres de contexto, com mais de 500 lemas e teoremas totalmente provados e verificados. Esta é provavelmente a formalização mais abrangente da teoria clássica das linguagens livres de contexto jamais feita no assistente de provas Coq, e inclui o importante resultado que é a formalização do Lema do Bombeamento para linguagens livres de contexto. As perspectivas para novos desenvolvimentos a partir deste trabalho são diversas e podem ser agrupadas em três áreas diferentes: inclusão de novos dispositivos e resultados, extração de código e aprimoramentos gerais das suas bibliotecas.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-02-21T16:47:42Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dvsTeseBiblioteca.pdf: 6571192 bytes, checksum: eb7914e5ffef25b8f01ff92d9a60c164 (MD5) / Made available in DSpace on 2017-02-21T16:47:42Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dvsTeseBiblioteca.pdf: 6571192 bytes, checksum: eb7914e5ffef25b8f01ff92d9a60c164 (MD5) Previous issue date: 2016-07-21 / FACEPE / Traditionally, single-domain recommender systems (SDRS) have achieved good results in recommending relevant items for users in order to solve the information overload problem. However, cross-domain recommender systems (CDRS) have emerged aiming to enhance SDRS by achieving some goals such as accuracy improvement, diversity, addressing new user and new item problems, among others. Instead of treating each domain independently, CDRS use knowledge acquired in a source domain (e.g. books) to improve the recommendation in a target domain (e.g. movies). Likewise SDRS research, collaborative filtering (CF) is considered the most popular and widely adopted approach in CDRS, because its implementation for any domain is relatively simple. In addition, its quality of recommendation is usually higher than that of content-based filtering (CBF) algorithms. In fact, the majority of the cross-domain collaborative filtering RS (CD-CFRS) can give better recommendations in comparison to single domain collaborative filtering recommender systems (SD-CFRS), leading to a higher users’ satisfaction and addressing cold-start, sparsity, and diversity problems. However, CD-CFRS may not necessarily be more accurate than SD-CFRS. On the other hand, context-aware recommender systems (CARS) deal with another relevant topic of research in the recommender systems area, aiming to improve the quality of recommendations too. Different contextual information (e.g., location, time, mood, etc.) can be leveraged in order to provide recommendations that are more suitable and accurate for a user depending on his/her context. In this way, we believe that the integration of techniques developed in isolation (cross-domain and contextaware) can be useful in a variety of situations, in which recommendations can be improved by information from different sources as well as they can be refined by considering specific contextual information. In this thesis, we define a novel formulation of the recommendation problem, considering both the availability of information from different domains (source and target) and the use of contextual information. Based on this formulation, we propose the integration of cross-domain and context-aware approaches for a novel recommender system (CD-CARS). To evaluate the proposed CD-CARS, we performed experimental evaluations through two real datasets with three different contextual dimensions and three distinct domains. The results of these evaluations have showed that the use of context-aware techniques can be considered as a good approach in order to improve the cross-domain recommendation quality in comparison to traditional CD-CFRS. / Tradicionalmente, “sistemas de recomendação de domínio único” (SDRS) têm alcançado bons resultados na recomendação de itens relevantes para usuários, a fim de resolver o problema da sobrecarga de informação. Entretanto, “sistemas de recomendação de domínio cruzado” (CDRS) têm surgido visando melhorar os SDRS ao atingir alguns objetivos, tais como: “melhoria de precisão”, “melhor diversidade”, abordar os problemas de “novo usuário” e “novo item”, dentre outros. Ao invés de tratar cada domínio independentemente, CDRS usam conhecimento adquirido em um domínio fonte (e.g. livros) a fim de melhorar a recomendação em um domínio alvo (e.g. filmes). Assim como acontece na área de pesquisa sobre SDRS, a filtragem colaborativa (CF) é considerada a técnica mais popular e amplamente utilizada em CDRS, pois sua implementação para qualquer domínio é relativamente simples. Além disso, sua qualidade de recomendação é geralmente maior do que a dos algoritmos baseados em filtragem de conteúdo (CBF). De fato, a maioria dos “sistemas de recomendação de domínio cruzado” baseados em filtragem colaborativa (CD-CFRS) podem oferecer melhores recomendações em comparação a “sistemas de recomendação de domínio único” baseados em filtragem colaborativa (SD-CFRS), aumentando o nível de satisfação dos usuários e abordando problemas tais como: “início frio”, “esparsidade” e “diversidade”. Entretanto, os CD-CFRS podem não ser mais precisos do que os SD-CFRS. Por outro lado, “sistemas de recomendação sensíveis à contexto” (CARS) tratam de outro tópico relevante na área de pesquisa de sistemas de recomendação, também visando melhorar a qualidade das recomendações. Diferentes informações contextuais (e.g. localização, tempo, humor, etc.) podem ser utilizados a fim de prover recomendações que são mais adequadas e precisas para um usuário dependendo de seu contexto. Desta forma, nós acreditamos que a integração de técnicas desenvolvidas separadamente (de “domínio cruzado” e “sensíveis a contexto”) podem ser úteis em uma variedade de situações, nas quais as recomendações podem ser melhoradas a partir de informações obtidas em diferentes fontes além de refinadas considerando informações contextuais específicas. Nesta tese, nós definimos uma nova formulação do problema de recomendação, considerando tanto a disponibilidade de informações de diferentes domínios (fonte e alvo) quanto o uso de informações contextuais. Baseado nessa formulação, nós propomos a integração de abordagens de “domínio cruzado” e “sensíveis a contexto” para um novo sistema de recomendação (CD-CARS). Para avaliar o CD-CARS proposto, nós realizamos avaliações experimentais através de dois “conjuntos de dados” com três diferentes dimensões contextuais e três domínios distintos. Os resultados dessas avaliações mostraram que o uso de técnicas sensíveis a contexto pode ser considerado como uma boa abordagem a fim de melhorar a qualidade de recomendações de “domínio cruzado” em comparação às recomendações de CD-CFRS tradicionais.

Made available in DSpace on 2014-07-29T14:57:51Z (GMT). No. of bitstreams: 1 dissertacao-rodrigohs.pdf: 1383844 bytes, checksum: b3fda2012ce5a20dc390677f308520e3 (MD5) Previous issue date: 2012-05-29 / Context models that describe dynamic context-aware scenarios usually need to be frequently updated. Some examples of situations that motivate these updates are the appearance of new services and context providers, the mobility of the entities described in these models, among others. Generally, updates on models imply redevelopment of the architectural components of context-aware systems based on these models. However, as these updates in dynamic scenarios tend to be more frequent, it is desirable that they occur at runtime. This dissertation presents an infrastructure for dynamic management of context models based on the fundamentals of complex event processing, or CEP. This infrastructure allows the fundamental abstractions from which a model is built to be updated at runtime. As these updates can impact systems based on the updated models, this dissertation identifies and analyzes these impacts, which are reproduced in a case study that aims to evaluate the proposed infrastructure by demonstrating how it deals with the impacts mentioned. / Modelos contextuais que descrevem cenários de computação sensível ao contexto dinâmicos normalmente precisam ser frequentemente atualizados. Alguns exemplos de situações que motivam essas atualizações são o surgimento de novos serviços e provedores de informações contextuais, a mobilidade das entidades descritas nesses modelos, dentre outros. Normalmente, atualizações em modelos implicam em redesenvolvimento dos componentes arquiteturais dos sistemas sensíveis ao contexto baseados nesses modelos. Porém, como em cenários dinâmicos essas atualizações tendem a ser mais frequentes, é desejável que elas ocorram em tempo de execução. Essa dissertação apresenta uma infraestrutura para gerenciamento dinâmico de modelos de contexto baseada nos fundamentos de processamento complexo de eventos, ou CEP. Essa infraestrutura permite que as abstrações fundamentais a partir das quais um modelo é construído sejam atualizadas em tempo de execução. Como essas atualizações podem causar impactos nos sistemas baseados nos modelos atualizados, essa dissertação identifica e analisa esses impactos, os quais são reproduzidos em um estudo de caso que tem como finalidade avaliar a infraestrutura proposta através da demonstração de como ela lida com os impactos mencionados.

Sabemos que a expressão dos cronotipos resulta de influências genéticas e ambientais. Existem evidências na literatura que nos permitem supor a participação do padrão temporal de exposição ao ciclo claro/escuro natural no estabelecimento dos cronotipos. Neste estudo nosso objetivo principal foi comparar a distribuição de cronotipos de dois grupos que vivem na mesma região rural, mas que apresentam padrões temporais de exposição ao ciclo claro/escuro muito distintos. Ao mesmo tempo, avaliamos a satisfação dos voluntários com seus horários de início de trabalho. Para isso estudamos dois grupos: Grupo de Trabalhadores em Ambiente Aberto (GTAA) e Grupo de Trabalhadores em Ambiente Fechado (GTAF). O GTAA foi composto por 29 voluntários com idade média de 30,8 ± 10,0 anos, enquanto o GTAF foi composto por 20 voluntários com idade média de 30,8 ± 9,8 anos. Aplicamos o questionário de matutinidade e vespertinidade e um questionário sobre os horários de trabalho para todos os voluntários, na maioria das vezes, em suas casas. Medidas das intensidades luminosas dos ambientes de trabalho dos voluntários foram coletadas. Comparamos a pontuação do questionário de cronotipos e a diferença entre o horário em que os voluntários trabalham e o horário em que gostariam de trabalhar entre os dois grupos. Usamos o teste estatístico de Kruskal-Wallis para essas comparações. Fizemos também uma regressão linear entre a pontuação do questionário de matutinidade e vespertinidade e a idade dos voluntários, um coeficiente de correlação foi obtido. Sugerimos com nossos resultados que o contexto fótico associado às naturezas espacial e temporal da ocupação laboral (contexto não-fótico) dos indivíduos pode modular a expressão dos cronotipos. Devido ao contexto fótico associado ao contexto não-fótico dos voluntários, o GTAA parece se ajustar melhor aos seus horários diurnos de trabalho. Finalmente, discutiremos neste trabalho a importância de se contextualizar socialmente a sincronização fótica de humanos para se estudar a expressão dos cronotipos. / It is known that the expression of the chronotypes results from both genetic and environmental influences. There are evidences in the literature which allow us to believe in the participation of the temporal pattern of exposition to the natural light/dark cycle in the establishment of the morningness/eveningness tendencies. In this study, our specific goal was to compare the distribution of the chronotypes in two groups of people sharing the same rural region for living, but with very different temporal patterns of exposition to the light/dark cycle. We also evaluated the satisfaction of the volunteers with their work schedule. Two groups were studied: Indoor Environment Group of workers (IEG) and Outdoor Environment Group (OEG) of workers. The OEG comprised 29 volunteers with average age of 30.8 ± 10.0 years old and the IEG 20 volunteers with average age of 30.8 ± 9.8 years old. We applied the Morningness-Eveningness Questionnaire and other questionnaire about the working time for all volunteers, most of times, in their homes. Measures of the light intensity of the volunteers\' working places were collected. We compared the scores of the questionnaire of chronotypes and the difference between the time in which the volunteers work and the time in which they would like to work, between the two groups. We used the statistic test of Kruskal-Wallis for these comparisons. We also applied a linear regression model between the score of the morningness-eveningness questionnaire and the age of the volunteers, obtaining a correlation coefficient. We suggest with our results that the photic context associated with the spacial and temporal natures of the working occupation, non-photic context, may modulate the expression of peoples\' chronotypes. Because of the photic context associated to the non-photic context of the volunteers, the OEG seems to have a better adjustment to the morning shift. Finaly, we discuss the importance of taking social context in consideration in studies of photic synchronization of humans.

[pt] A difusão das redes sem fio IEEE 802.11 e o avanço das técnicas de posicionamento baseadas na força de sinal de rádio frequência (RF) (e.g., sensores, algoritmos de triangulação, etc.) têm motivado o desenvolvimento de aplicações e serviços sensíveis ao contexto e sua localização (Location Based Services). Essas aplicações oferecem vários benefícios para os usuários finais, por exemplo, adaptação às limitações dos dispositivos e da rede sem fio, acesso às informações de localização, ou a capacidade de enviar notificações baseadas na localização ou na proximidade entre os usuários (e.g., Geocaching). Entretanto, há dois desafios principais relacionados ao desenvolvimento e uso de aplicações sensíveis ao contexto: a complexidade em desenvolver os serviços de provisão de contexto e a necessidade de manter a privacidade da informação de contexto (e.g., localização) do usuário. Para auxiliar o desenvolvimento de aplicações sensíveis ao contexto, projetamos e implementamos alguns serviços que constituem o núcleo de uma arquitetura de provisão de contexto, chamada MoCA (Mobile Collaboration Architecture). Esses serviços implementam a coleta, o processamento e a difusão da informação de contexto através de interfaces de comunicação síncronas e baseadas em eventos. A MoCA serviu de base para o desenvolvimento da nossa pesquisa sobre privacidade na qual projetamos um serviço que auxilia o usuário no controle de privacidade das suas informações de contexto, em especial, da sua informação de localização. Como parte do nosso trabalho, definimos um modelo conceitual que serviu de base para o desenvolvimento do serviço de privacidade proposto (a ser utilizado por uma comunidade de usuários) e discutimos alguns requisitos que devem ser levados em conta no projeto de um serviço deste gênero. A maioria destes requisitos delinearam o projeto e implementação do Context Privacy Service (CoPS). Este serviço foi integrado aos serviços de provisão de contexto da arquitetura MoCA. / [en] The widespread dissemination of IEEE 802.11 networks and the enhancement of positioning techniques based on RF signal strength (e.g., sensors, positioning triangulation algorithms, etc) have fostered the development of location-based and context-aware services and applications. These applications offer several benefits to the end-users, e.g. adaptation to the device and wireless network limitations, access to location- specific information, or the ability to send location-specific notifications to other users (e.g., Geocaching). However, there are two main challenges concerning the development and use of context-aware applications: the complexity in developing context provisioning services and the need to guarantee the privacy of the users' context information (e.g., their location). In order to support the development of context-aware applications, we have designed and implemented some services that constitute the core of a context provisioning architecture called MoCA (Mobile Collaboration Architecture). These services implement the gathering, processing and diffusion of context information through synchronous and event-based communication interfaces. MoCA architecture has been used as a basis to the development of our research about privacy in which we have designed a service that aids the end-user in defining the privacy level for his/her contextual information, and in particular for his/her location information. As part of our work, we define the conceptual model underlying our privacy control service (targeted at a community of users) and discuss the most important requirements that should be conside- red in the design of such a service. Most of these requirements have guided the design and implementation of the Context Privacy Service (CoPS). This service has been integrated to the context provisioning services of the MoCA middleware.

Magister Educationis - MEd / The test context is of paramount importance in language testing as it provides an understanding of the kind of tasks to be included in the test, how these tasks are executed by the test takers and how they can be efficiently administered. The objective of this study was to investigate the extent to which the context of the DR Congo English state examination (ESE) is valid and to come out with some useful suggestions that are likely to improve its validity. Two basic theories, the modern validity theory and the schema theory, informed this study. Weir's (2005) socio-cognitive framework was used to build the validity argument for the evaluation of the English state examination. A mixed method was used where the research design consisted of the combination of both qualitative and quantitative data during the collection and analysis stages. The content document analysis method was used to examine the content of the different state examination papers so as to identify the main features of the test, and the statistic (descriptive) method was used to quantify observations identified in the state examination papers and to evaluate the context validity of the ESE. Three techniques were used to collect the research data: the questionnaire, the test, and the interview. Three main findings of this study were reported: (1) the conditions under which the ESE tasks are performed and the relevance of these tasks to the test domain and characteristics are still far to contribute to the quality of evaluation of high school finalist students; (2) the extent to which the ESE includes tasks that take into consideration the nature of information in the text as well as the knowledge required for completing the task is globally good; (3) the conditions under which the test takes place are poor and these conditions affect the validity of test scores. The study recommends the test developers to approximate test tasks to those students have been exposed to in classroom situations and those they are likely to encounter in real life. It also recommends all the people involved in the administration of the test to adhere to high ethical standards. / South Africa

The technological advances in wireless networks, smart phones, social networks, embedded sensor technologies and the wide spread of mobile devices have exposed customers to number of services. With these advanced technological innovations, computing capability and connectivity, customers look forward to get useful services and information by means of their mobile devices anywhere and at anytime thereby saving time and money. The importance of mobile commerce is increasing every day, since the mobile devices are becoming central part of our lives. One of the challenge here is the ability to reinforce the application behavior by utilizing context information. The analysis and utilization of context information is necessary to build intelligent applications and thereby focusing on less user attention by understanding the current situation. The information about the current location of a mobile customer, the time of request, and personal characteristics like nature of work, profession and economic status are utilized by applications to provide accurate context-aware services. Many of context-aware applications focus mainly on user activity, preferences which are not sufficient to provide context-aware intelligent services. However, there are few works in developing an integrated model for analyzing the context information. Many authors describe the context representation using five elements like who, what, where, when and how to provide a user centric view without emphasizing on the feature of generality and structural representation of context parameters. Since context information takes multiple forms, it is essential and necessary to make broad classification which helps application designers and developers to deal with possible contexts and their impact on application behavior. In addition, the context classification enables to understand complex customer situations due to changing mobile environment. Therefore, it is required to design a model which analyzes the context information of customers in a dynamic environment and hence, provide real time accurate service. The design and development of context-aware mobile commerce services requires a general conceptual model which can handle any type of context information for different applications. Due to the dynamic nature of business environment and also the customer preferences keep emerging, there is a need to develop business model which adapts to changing environment. To understand the current situation of customers in such highly dynamic environments and to enable the business transactions quickly among parties involved, it is essential to construct and analyze an integrated view of information from distinct sources. The adaptation of the provided services based on customer needs depends when the relevant context information is self-described in the form of beliefs. The observations made on combination of context information are deduced into beliefs as a result the decision making time to provide service reduces considerably. The aim of the thesis, is to design and develop a context-aware system which has been applied for mobile commerce environment by considering the customer context information. To do this, we have designed two models: the Context-Information, Observation and Belief (C-IOB)model and the commercial business model. The main function of C-IOB model is to support the application to identify a suitable context-aware service and to execute business transaction for a customer by analyzing the context information in the form of beliefs. We classify the used Context Information(CI)into four types: physical, system, application and social environment. The business model discusses the formal description of participants who are involved in commercial business. The C-IOB model The Context Information, Observation and Belief model deduces beliefs on customer, by combination of available context information during transaction execution or service provision. The beliefs represent the various situations of customers based on specific nature of the applications. The beliefs developed about an entity(e.g. ,person, place, thing) are primitive in most theories of decision making so that applications can use these beliefs to identify and execute context-aware services. The C-IOB model reduces the solution search space, since the knowledge about an entity is organized using cognitive factors, which maps user context information into real world observations and beliefs, as a result the decision making time by the system reduces considerably. The five CI -constructs: who, what, where, when and how enable many types of context information acquisition in our work. The commercial business model A commercial business model mainly involves the formal description of business participants who are involved in commercial business transactions. To meet the growing needs and to fulfill high expectations of customers, it is very important that application designers have to address the issue of building viable business models for commercial environment. The business model describes how an enterprise or an organization captures and delivers economical value to customers. In particular, the customers play major role in transactions execution and hence understanding and identifying the needs of customer is an important issue in building the business model for commercial purpose. Mobile Commerce Environment Mobile commerce environment (MCE) is one of the specific forms of commercial business model. It deals with transactions like purchases with the objective of supplying commodities like goods and services to customers using mobile devices. A Mobile commerce environment is established by considering set of customers, vendors and bankers, who are involved in commercial business activities like buying of electronic goods and services. The environment is based on certain factors like the type of customers, the type of transactions and the type of electronic products involved in purchasing. M-commerce is one of the most effective and useful ways of conducting business as the customers are constantly using mobile devices and it significantly assists customers in making transactions anywhere, anytime and thereby improving the customer satisfaction. C-IOB model based mobile commerce environment Mobile commerce applications are required to be flexible, in providing services due to inherent anytime and anywhere paradigm. The traditional systems during commercial business transactions, take large time to search the right product, which leads to more utilization of device resources like memory and computational power. In addition, the users are striked with more information which is not significant. Therefore, there is a need to design applications, which identify the customer requirements by acquiring the context information from distinct sources and thereby providing timely and specific information or services to the customer. Hence, to adapt services based on various situations, it is required to develop a systematic approach for representation and utilization of context information modified to special characteristics of mobile commerce applications. The mobile commerce environment uses C-IOB model for analyzing the relevant context information of customers and the context based beliefs helps to identify a suitable service for an end customer, thereby reducing mobile transaction execution time and providing customer benefits. The simulation environment consists of 10,000 electronic products which are categorized based on technical and commercial features. The simulation is carried out with ten mobile commerce transactions, the database consists of information about500 customers and 100vendors who deal with electronic products selling and10bankersfor money transactions. The customer context information is acquired from physical, system, application and social environment. When customers ends are quest for a service, the current context information is acquired, a set of observations is formulated and belief is deduced. The customer is provided with relevant information or service based on deduced belief. The simulation exhaustively tests the working of the system for mobile commerce transactions under different context environments. Some of the case studies are designed by applying the C-IOB model which includes placing the purchase order for the product, money transfer and after sales service. In summary, we have developed a context-aware system by using C-IOB model and also the design of commercial business model. To evaluate the performance of the system, we have incorporated context-awareness aspect for 10 business transactions applied to mobile commerce. The proposed system using C-IOB model provides customer required services as accurately as possible. The system has the capability to adapt to real time situation of customer needs, thereby enhancing the customer satisfaction. The simulation results have shown that the time to execute mobile commerce transactions is less using context based beliefs compared to context unaware approach. The accuracy of the system with belief based approach is higher than without context information. The customer benefits in business transaction are also enhanced by our design approach.

Diversos pesquisadores vêm investigando métodos e técnicas para tornar possível às pessoas anotarem vídeos de modo transparente. A anotação pode ser realizada com a fala, com o uso de tinta digital ou algum outro meio que possa ser capturado enquanto a pessoa assiste ao vídeo. Tais anotações podem ser compartilhadas com outras pessoas, que podem estar assistindo ao mesmo vídeo em um mesmo instante ou em momentos diferentes, sendo interessante ainda que as anotações possam ser realizadas por várias pessoas de modo colaborativo. O paradigma Watch-and-Comment (WaC) propõe a captura transparente de anotações multimodais de usuários enquanto os mesmos assistem e comentam um vídeo. Como resultado desse processo, é gerado um vídeo digital interativo integrando o conteúdo original às anotações realizadas. Esta dissertação tem por objetivo explorar conceitos de computação ubíqua, redes sociais, redes peer-to-peer e TV interativa na proposta de um modelo arquitetural de ciência de informações de contexto para aplicações definidas segundo o paradigma WaC. O modelo explora a integração de um serviço ao paradigma, que auxilie ou forneça alternativas para que aplicações, do momento da captura ao acesso das anotações, utilizem informações de contexto do usuário, do vídeo e das anotações. O modelo também auxilia no estudo de colaboração entre usuários que realizam anotações em vídeos. Outra contribuição da dissertação é a prototipação de aplicações para avaliar e refinar o modelo proposto. São apresentadas extensões para a aplicação WaCTool, considerando o uso de redes sociais e de alternativas para a anotação em vídeos / Researchers have been investigating methods and techniques to allow people to annotate videos ubiquitously. Annotations can be made using voice, digital ink or some other media that can be captured while a person watches a video. These annotations can be shared with other people, who can be watching a video on the same time or at a different one. Also, these annotations can be made by many people collaboratively. The Watch-and-Comment (WaC) paradigm aims at capturing multimodal annotations in an ubiquitous way, while users watch and comment some video. As a result, an interactive digital video is generated combining the original content and the annotations. The work reported on this thesis explores concepts such as ubiquitous computing, social networks, peer-to-peer networks and interactive digital TV, to propose an architectural context-aware model to the applications defined by WaC paradigm. The model proposes the integration of a new service to the paradigm, supporting applications on the annotation process by offering capture alternatives and using context information from user, video and annotations. Also, the model provides a study in collaborative annotation process. Another contribution of this thesis is the prototypes built to evaluate and upgrade the proposed model. The prototypes are extensions from WaCTool, considering the use of social networks and alternatives to annotate in videos