Home-based rehabilitation has evolved in recent years as a cost-effective and convenient alternative to traditional clinical rehabilitation. Researchers have developed various types of sensors-based rehabilitation systems that incorporate Virtual Reality games aimed to offer the patient an entertaining and beneficial training experience from the comfort of home. This has consequently created the need to design reliable assessment and adaptation mechanisms that are able to measure and analyze the patient's performance and condition, and to accordingly make proper adjustments that conform to the abilities of the patient during the training. In this dissertation, we introduce our context-based adaptive home-based rehabilitation framework (CAHR) that offers the patients a rehabilitation environment that can adapt based on their physical, physiological, and psychological context, while taking into consideration the environmental conditions that may hinder their progress. CAHR is a generic framework that can be implemented to fit any of the upper or lower extremity rehabilitation. However, in this dissertation, we base our modeling and analysis mainly on the wrist. In CAHR, the physical condition of the patient is assessed by a fuzzy logic-based mechanism that uses the various kinematics captured during the training to provide a quantified value which reflects the Quality of Physical Performance of the patient. The rehabilitation task adaptation is achieved based on a special algorithm that defines how the physical training, psychophysiological responses, and environmental conditions must be manipulated in order to match the desired performance target parameters set by the therapist. The simulation results have shown that the proposed adaptation engine can properly adjust the rehabilitation environment based on different simulated performance behavior that might be produced by a patient. In addition, training with a special game that has been designed based on the developed framework has shown improvement in the physical capabilities of two patients suffering from upper extremity impairments.

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Le développement d'applications pour l'informatique pervasive présente un certain nombre de défis pour l'ingénierie des logiciels. En particulier, l'adaptation des applications sensibles au contexte : adaptation à l’environnement (localisation, temps, condition, …), à la connectivité (débit, protocole, …), aux limitations de l'appareil (écran, format de média, …) et même à l’utilisateur (handicap physique, capacité, …). Dans ce contexte où le multimédia, la mobilité des utilisateurs et l'ubiquité des applications se généralisent, les fournisseurs de logiciel souhaitent offrir des applications adaptables (sensibles au contexte). Beaucoup d’efforts ont été consacrés à l’assemblage et au réassemblage de composants, ainsi qu’à l’adaptation fonctionnelle par remplacement ou reconfiguration des composants afin de satisfaire le nouveau besoin ou le nouveau contexte. La problématique que nous abordons dans cette thèse est celle de l’hétérogénéité comportementale ou sémantique des composants. L’objectif est de fournir des mécanismes permettant l’adaptation des flux de données multimédia dans des applications basées composants. Pour cela, l’architecture doit être capable de vérifier la possibilité d’assemblage des composants à partir de leurs manifestes (un manifeste doit contenir les informations techniques d’un composant). L’assemblage peut ne pas se faire pour deux raisons : incompatibilité fonctionnelle et/ou comportementale. Notre travail porte sur la deuxième raison, dans le cas où les interfaces d’un composant ne seront pas compatibles avec celles des composants voisins. Par exemple un composant fournit des images de type PNG, alors que l’autre n’accepte que des images JPEG. La mise en évidence de l’interopérabilité des composants dans un assemblage est une nécessité dans de telles approches. En effet, les architectures logicielles valident les aspects fonctionnels, ce qui n’est pas suffisant pour garantir un assemblage réaliste et remédier aux problèmes d’hétérogénéité des flux de données échangés. Nous proposons, pour mettre en évidence l’interopérabilité et permettre de trouver des solutions aux problèmes d’hétérogénéité, une approche basée modèle appelée MMSA (Meta-model for MultiMedia Software Architecture). Elle permet la description d’architectures logicielles exprimant un système logiciel comme une collection de composants qui manipulent différents types et formats de données et qui interagissent par l’intermédiaire de connecteurs d’adaptation. Nous définissons aussi un profil UML 2.0 pour exprimer et modéliser les nouveaux concepts et contraintes du méta modèle MMSA. La transition vers un profil UML est assurée par les mécanismes d'extension fournis par UML 2.0 afin d'améliorer la vérification et la cohérence des architectures décrites en MMSA. Nous proposons pour assurer la cohérence des applications vis à vis des changements du contexte, une plate-forme d’adaptation dynamique. Cette plate-forme surveille et contrôle l’exécution des applications multimédia afin de détecter les changements éventuels du contexte. En cas d’un changement, la plate-forme cherche les solutions possibles et prend la décision adéquate pour l’adaptation de l’application au nouveau contexte. Ensuite, la plate-forme cherche et choisit les services d’adaptation nécessaires afin de les intégrer dans des connecteurs d’adaptation et les réassembler avec les composants métiers de l’application. Afin d’examiner la projection de MMSA en UML 2.0, les contraintes OCL ont été évaluées dynamiquement sur un modèle de système de surveillance. Nous proposons aux architectes logiciels, un outil qui donne la possibilité de vérifier le modèle d’architecture à chaque modification afin d’assurer sa cohérence structurelle et sémantique. Les différents tests et validations effectués sur les modèles d’architecture garantissent parfaitement notre projection. / The development of applications for pervasive computing presents a number of challenges for software engineering. In particular, the adaptation of context-aware applications: adapting to the environment (location, time, condition, etc.), connectivity (bit-rate, protocol, etc.), the limitations of the device (screen size media ...) and even the user (physical handicaps, ability, etc.). The programmer is always faced with a complex combination of factors that occur throughout the application. In this context where the multimedia, the mobility of user and the ubiquitous application generalizes, providers want to offer adaptable software applications (context sensitive). Much effort has been devoted to assembly and reassembly of components, thus to the functional adaptation by replacement or reconfiguration of the components in order to satisfy the new need or the new context. The problem we tackle in this thesis is that of semantic and behavioral heterogeneity of components. The objective is to provide mechanisms for adapting multimedia data flows in applications based components, i.e. ensuring the assembly of heterogeneous components. For this, the architecture must be able to check the possibility of assembling components from the manifest (a manifest must contain the technical information of component). The assembly may not accept for two reasons: functional and/or behavioral incompatibility. Our work focuses on the second reason, in case the interfaces of component will not be compatible with the interfaces of adjacent components. For example, it provides images of PNG type, while the other accepts only JPEG images. The taken into account of components interoperability in an assembly is a necessity in such approaches. Indeed, software architectures validate the functional aspects, which is not sufficient to ensure a realistic assembly and to remedy the problems of heterogeneous of data flow exchanged. We propose to take into account the interoperability and to find solutions to problems of heterogeneity, an approach called model MMSA (Meta-Model for Multimedia Software Architecture). It allows the description of software architectures expressing a software system as a collection of components that handle various data types and formats and which interact through connectors to adaptation. We also define a UML 2.0 profile to express and model the new concepts and constraints of MMSA meta-model. The transition to a UML profile is provided by the extension mechanisms provided by UML 2.0 in order to improve the verification and consistency of architectures described in MMSA. We propose for ensure the coherence of applications aim at screw of changing context, a platform of dynamic adaptations. The dynamic adaptation is the process by which a software application is modified in order to take into account a change, be it level of the environment or the application itself, the platform monitors and controls the execution of multimedia applications to detect any change of context. In the event of a change, the platform seeks the possible solutions and takes the appropriate decision to adapt the application to the new context. Then, the platform seeks and selected the services of adaptation necessary in order to integrate them in connectors of adaptation and reassembled with the business components of application. In order to examine the projection of MMSA in UML 2.0, the OCL constraints were dynamically evaluated on a model of monitoring system. We have proposed to the software architects, a tool which gives the possibility of checking the model of architecture to each modification in order to ensure its structural and semantic coherence. The various tests and validations carried out on the models of architecture guarantee our projection perfectly. This visual model supports the creation and the management of models MMSA for software applications.

This thesis is concerned with the development of new mathematical models for the IEEE 802.11??s access mechanisms, with a particular focus on DCF and EDCA. Accurate mathematical models for the DCF and EDCA access mechanisms provide many benefits, such as improved performance analysis, easier network capacity planning, and robust network design. A feature that permeates the work presented in this thesis is the application of our new models to network environments where both saturated and non-saturated traffic sources are present. The scenario in which multiple traffic sources are present is more technically challenging, but provides for a more realistic setting. Our first contribution is the development of a new Markov model for non-saturated DCF in order to predict the network throughput. This model takes into account several details of the protocol that have been hitherto neglected. In addition, we apply a novel treatment of the packet service time within our model. We show how the inclusion of these effects provides more accurate predictions of network throughput than earlier works. Our second contribution is the development of a new analytical model for EDCA, again in order to predict network throughput. Our new EDCA model is based on a replacement of the normal AIFS parameter of EDCA with a new parameter more closely associated with DCF. This novel procedure allows EDCA to be viewed as a modified multi-mode version of DCF. Our third contribution is the simultaneous application of our new Markov models to both the non-saturated and the saturated regime. Hitherto, network throughput predictions for these regimes have required completely separate mathematical models. The convergence property of our model in the two regimes provides a new method to estimate the network capacity of the network. Our fourth contribution relates to predictions for the multimedia capacity of 802.11 networks. Our multimedia capacity analysis, which is based on modifications to our Markov model, is new in that it can be applied to a broad range of quality of service requirements. Finally, we highlight the use of our analysis in the context of emerging location-enabled networks.

Traditionally the Internet is used for the following applications: FTP, e-mail and Web traffic. However in the recent years the Internet is increasingly supporting emerging applications such as IP telephony, video conferencing and online games. These new applications have different requirements in terms of throughput and delay than traditional applications. For example, interactive multimedia applications, unlike traditional applications, have more strict delay constraints and less strict loss constraints. Unfortunately, the current Internet offers only a best-effort service to all applications without any consideration to the applications specific requirements. In this thesis three existing Active Queue Management (AQM) mechanisms are modified by incorporating into these a control function to condition routers for better Quality of Service (QoS). Specifically, delay is considered as the key QoS metric as it is the most important metric for real-time multimedia applications. The first modified mechanism is Drop Tail (DT), which is a simple mechanism in comparison with most AQM schemes. A dynamic threshold has been added to DT in order to maintain packet queueing delay at a specified value. The modified mechanism is referred to as Adaptive Drop Tail (ADT). The second mechanism considered is Early Random Drop (ERD) and, iii in a similar way to ADT, a dynamic threshold has been used to keep the delay at a required value, the main difference being that packets are now dropped probabilistically before the queue reaches full capacity. This mechanism is referred to as Adaptive Early Random Drop (AERD). The final mechanism considered is motivated by the well known Random Early Detection AQM mechanism and is effectively a multi-threshold version of AERD in which packets are dropped with a linear function between the two thresholds and the second threshold is moveable in order to change the slope of the dropping function. This mechanism is called Multi Threshold Adaptive Early Random Drop (MTAERD) and is used in a similar way to the other mechanisms to maintain delay around a specified level. The main focus with all the mechanisms is on queueing delay, which is a significant component of end-to-end delay, and also on reducing the jitter (delay variation) A control algorithm is developed using an analytical model that specifies the delay as a function of the queue threshold position and this function has been used in a simulation to adjust the threshold to an effective value to maintain the delay around a specified value as the packet arrival rate changes over time. iv A two state Markov Modulated Poisson Process is used as the arrival process to each of the three systems to introduce burstiness and correlation of the packet inter-arrival times and to present sudden changes in the arrival process as might be encountered when TCP is used as the transport protocol and step changes the size of its congestion window. In the investigations it is assumed the traffic source is a mixture of TCP and UDP traffic and that the mechanisms conserved apply to the TCP based data. It is also assumed that this consists of the majority proportion of the total traffic so that the control mechanisms have a significant effect on controlling the overall delay. The three mechanisms are evaluated using a Java framework and results are presented showing the amount of improvement in QoS that can be achieved by the mechanisms over their non-adaptive counterparts. The mechanisms are also compared with each other and conclusions drawn.

This thesis is concerned with the development of new mathematical models for the IEEE 802.11??s access mechanisms, with a particular focus on DCF and EDCA. Accurate mathematical models for the DCF and EDCA access mechanisms provide many benefits, such as improved performance analysis, easier network capacity planning, and robust network design. A feature that permeates the work presented in this thesis is the application of our new models to network environments where both saturated and non-saturated traffic sources are present. The scenario in which multiple traffic sources are present is more technically challenging, but provides for a more realistic setting. Our first contribution is the development of a new Markov model for non-saturated DCF in order to predict the network throughput. This model takes into account several details of the protocol that have been hitherto neglected. In addition, we apply a novel treatment of the packet service time within our model. We show how the inclusion of these effects provides more accurate predictions of network throughput than earlier works. Our second contribution is the development of a new analytical model for EDCA, again in order to predict network throughput. Our new EDCA model is based on a replacement of the normal AIFS parameter of EDCA with a new parameter more closely associated with DCF. This novel procedure allows EDCA to be viewed as a modified multi-mode version of DCF. Our third contribution is the simultaneous application of our new Markov models to both the non-saturated and the saturated regime. Hitherto, network throughput predictions for these regimes have required completely separate mathematical models. The convergence property of our model in the two regimes provides a new method to estimate the network capacity of the network. Our fourth contribution relates to predictions for the multimedia capacity of 802.11 networks. Our multimedia capacity analysis, which is based on modifications to our Markov model, is new in that it can be applied to a broad range of quality of service requirements. Finally, we highlight the use of our analysis in the context of emerging location-enabled networks.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-08-17T14:49:52Z No. of bitstreams: 1 IVO AUGUSTO ANDRADE ROCHA CALADO - DISSERTAÇÃO PPGCC 2010..pdf: 1680910 bytes, checksum: 4450f567f3a50b0c351dd900f342ea2f (MD5) / Made available in DSpace on 2018-08-17T14:49:52Z (GMT). No. of bitstreams: 1 IVO AUGUSTO ANDRADE ROCHA CALADO - DISSERTAÇÃO PPGCC 2010..pdf: 1680910 bytes, checksum: 4450f567f3a50b0c351dd900f342ea2f (MD5) Previous issue date: 2010-03-11 / A disseminação dos diferentes tipos de aplicações multimídia tem possibilitado uma maior interatividade entre usuários nas mais diversas localizações. Contudo, a falta de mecanismos que garantam níveis de qualidade de serviço, no núcleo da Internet, obriga tais aplicações a realizarem um contínuo processo de adaptação dos fluxos multimídia, de forma a atender aos níveis de transmissão disponíveis, tornando esta uma tarefa adicional no desenvolvimento de tais aplicações. Por outro lado, diante da grande heterogeneidade existente tanto em termos de recursos de transmissão disponíveis quanto de requisitos dos terminais envolvidos, a implementação de uma única abordagem de adaptação que dê um suporte satisfatório a todos os cenários mostra-se muitas vezes inviável, fazendo-se necessário a utilização de diferentes abordagens, de acordo com o contexto de utilização. Como consequência tem-se um aumento na complexidade do desenvolvimento. Neste trabalho apresenta-se uma infraestrutura para o desenvolvimento de aplicações multimídia com suporte à adaptação de fluxos. A partir desta infraestrutura, é possível obter uma flexibilização em como o processo de adaptação de fluxos multimídia será realizado, atendendo aos requisitos dos diferentes tipos de aplicações. Neste sentido, de forma a validar a infraestrutura proposta, foi realizado o desenvolvimento de dois estudos de caso visando demonstrar tanto o suporte oferecido ao desenvolvimento de aplicações multimídia quanto à extensibilidade da infraestrutura a partir da inclusão de novos mecanismos de adaptação. / The spread of different kinds of multimedia applications has enabled a powerful interaction between users in diverse locations. However, the best effort service nature of the Internet requires a continuous process of stream adaptation, in order to fetch such differents scenarios of transmission. As a consequence, this additional task should be met in the multimedia application development. On the other hand, according to the great heterogeneity of both transmission resources and terminal requirements, it is impracticable to define a unique adaptation method which be optimal for all scenarios. Therefore, we have an increasing complexity of multimedia application development. This work presents an infrastructure to multimedia application development to support stream adaptation. It provides a flexible way to implement and to use adaptation methods, meeting the requirements of different applications. Within this context, in order to validate the developed work, it was implemented two case studies: how to develop multimedia applications with support of stream adaptation and present the extensibility provided by proposed infrastructure through the dynamic addition of new adaptation methods.

É notável o avanço da utilização de aplicações multimídia nos diversos setores da atividade humana. Independente da área, seja ela educação ou entretenimento, a possibilidade de agregar recursos dinâmicos como áudio e vídeo aos já largamente utilizados como texto e imagem acarreta em benefícios aos usuários destas aplicações. Além disso, com a popularização da Internet, ha uma crescente demanda pela sua execução em ambientes distribuídos. Este trabalho teve como objetivo desenvolver MUSE, um ambiente gráfico para modelagem de aplicações multimídia interativas. Através de uma interface gráfica avançada e de um novo modelo de autoria de alto nível, e possível a criação de sistemas complexos de forma rápida e intuitiva. 0 modelo de autoria proposto neste trabalho e adotado pelo ambiente prevê a possibilidade de os elementos que constituem a aplicação estarem dispersos em uma rede de computadores, permitindo a definição de limiares aceitáveis de atraso e componentes alternativos. Pela grande expressividade do modelo, no entanto, podem ser geradas especificações com inconsistências lógicas e temporais. Por esta razão, o ambiente prove ainda especificações E-LOTOS - uma extensão temporal de LOTOS - utilizadas para fins de analise e verificação, permitindo a validação dos requisitos temporais das aplicações definidas pelo autor. A formalização das especificações através de uma TDF, além de viabilizar sua validação, prove descrições sem ambigüidades, que podem ser alternativamente utilizadas por autores que sejam familiarizados com a técnica de descrição formal. Este trabalho é parte do projeto DAMD (Design de Aplicações Multimídia Distribuídas) dentro do programa PROTEM fase 2, que tem por objetivo fornecer uma metodologia que cubra o ciclo completo das aplicações multimídia distribuídas e que permita a um autor não especializado em métodos formais desenvolver essas aplicações naturalmente. / It is notable the advance of multimedia applications utilization in several fields of human activity. Independent from the area, whether education or entertainment, the possibility to aggregate dynamic resources like audio and video to the ones already widely used like text and image results in benefits to the users of such applications. Besides, with the popularization of the Internet, there is an increasing demand for their execution in distributed environments. This work presents MUSE, a graphical environment for modeling interactive multimedia applications. Through an advanced graphic interface and a new high-level authoring model, it is possible to create complex systems in a fast and intuitive way. The authoring model proposed in this work and adopted by the tool deals with media objects distributed in a computer network, allowing the definition of acceptable delay thresholds and alternative media objects. Due to the large expressiveness of the model, however, specifications can be generated with logical and temporary inconsistencies. For this reason, the tool also provides E-LOTOS specifications used with the purpose of analyzing and verifying the applications aiming at validating the temporal requirements defined by the author. The formalization of the specifications by means of a TDF, beyond making their validation possible, provides descriptions free of ambiguities, which may be alternatively used by authors familiarized with the formal description technique. This work is part of DAMD (Distributed Multimedia Applications Design) project, sponsored by the Brazilian research council. Its main objectives are to provide a methodology to completely cover the distributed multimedia applications development cycle and to allow authors who are not expert in formal methods to easily develop their applications.

É notável o avanço da utilização de aplicações multimídia nos diversos setores da atividade humana. Independente da área, seja ela educação ou entretenimento, a possibilidade de agregar recursos dinâmicos como áudio e vídeo aos já largamente utilizados como texto e imagem acarreta em benefícios aos usuários destas aplicações. Além disso, com a popularização da Internet, ha uma crescente demanda pela sua execução em ambientes distribuídos. Este trabalho teve como objetivo desenvolver MUSE, um ambiente gráfico para modelagem de aplicações multimídia interativas. Através de uma interface gráfica avançada e de um novo modelo de autoria de alto nível, e possível a criação de sistemas complexos de forma rápida e intuitiva. 0 modelo de autoria proposto neste trabalho e adotado pelo ambiente prevê a possibilidade de os elementos que constituem a aplicação estarem dispersos em uma rede de computadores, permitindo a definição de limiares aceitáveis de atraso e componentes alternativos. Pela grande expressividade do modelo, no entanto, podem ser geradas especificações com inconsistências lógicas e temporais. Por esta razão, o ambiente prove ainda especificações E-LOTOS - uma extensão temporal de LOTOS - utilizadas para fins de analise e verificação, permitindo a validação dos requisitos temporais das aplicações definidas pelo autor. A formalização das especificações através de uma TDF, além de viabilizar sua validação, prove descrições sem ambigüidades, que podem ser alternativamente utilizadas por autores que sejam familiarizados com a técnica de descrição formal. Este trabalho é parte do projeto DAMD (Design de Aplicações Multimídia Distribuídas) dentro do programa PROTEM fase 2, que tem por objetivo fornecer uma metodologia que cubra o ciclo completo das aplicações multimídia distribuídas e que permita a um autor não especializado em métodos formais desenvolver essas aplicações naturalmente. / It is notable the advance of multimedia applications utilization in several fields of human activity. Independent from the area, whether education or entertainment, the possibility to aggregate dynamic resources like audio and video to the ones already widely used like text and image results in benefits to the users of such applications. Besides, with the popularization of the Internet, there is an increasing demand for their execution in distributed environments. This work presents MUSE, a graphical environment for modeling interactive multimedia applications. Through an advanced graphic interface and a new high-level authoring model, it is possible to create complex systems in a fast and intuitive way. The authoring model proposed in this work and adopted by the tool deals with media objects distributed in a computer network, allowing the definition of acceptable delay thresholds and alternative media objects. Due to the large expressiveness of the model, however, specifications can be generated with logical and temporary inconsistencies. For this reason, the tool also provides E-LOTOS specifications used with the purpose of analyzing and verifying the applications aiming at validating the temporal requirements defined by the author. The formalization of the specifications by means of a TDF, beyond making their validation possible, provides descriptions free of ambiguities, which may be alternatively used by authors familiarized with the formal description technique. This work is part of DAMD (Distributed Multimedia Applications Design) project, sponsored by the Brazilian research council. Its main objectives are to provide a methodology to completely cover the distributed multimedia applications development cycle and to allow authors who are not expert in formal methods to easily develop their applications.