Dissertations / Theses on the topic 'Mobile Computing, Software Architecture'

Interactions in the style of the ubiquitous computing paradigm are possible today, but only in handcrafted environments within one administrative and technological realm. This thesis describes an architecture (called Continuum), a design that realises the architecture, and a proof-of-concept implementation that brings ubiquitous computing to chaotic environments. Essentially, Continuum enables an ecology at the edge of the network, between users, competing service providers from overlapping administrative domains, competing internet service providers, content providers, and software developers that want to add value to the user experience. Continuum makes the ubiquitous computing functionality orthogonal to other application logic. Existing web applications are augmented for ubiquitous computing with functionality that is dynamically compiled and injected by a middleware proxy into the web pages requested by a web browser at the user?s mobile device. This enables adaptability to environment variability, manageability without user involvement, and expansibility without changes to the mobile. The middleware manipulates self-contained software units with precise functionality (called frames), which help the user interact with contextual services in conjunction with the data to which they are attached. The middleware and frame design explicitly incorporates the possibility of discrepancies between the assumptions of ubiquitous-computing software developers and field realities: multiple administrative domains, unavailable service, unavailable software, and missing contextual information. A framework for discovery and authorisation addresses the chaos inherent to the paradigm through the notion of role assertions acquired dynamically by the user. Each assertion represents service access credentials and contains bootstrapping points for service discovery on behalf of the holding user. A proof-of-concept prototype validates the design, and implements several frames that demonstrate general functionality, including driving discovery queries over multiple service discovery protocols and making equivalences between service types, across discovery protocols.

Os sistemas de modelagem de distribuição provável de espécie são utilizados para identificar regiões onde há maior probabilidade de uma determinada espécie viver, baseado nas características ambientais de localizações onde é conhecido que há presença daquela espécie. Estes sistemas requerem computação de alto desempenho devido à grande quantidade de dados que precisam ser processados para se gerar um modelo com a distribuição provável. Um momento importante do processo de modelagem de distribuição de espécies é a coleta dos dados, no qual os pesquisadores vão a campo para identificar alguns pontos de presença ou ausência, no entanto este processo é feito de forma ainda manual. Este trabalho apresenta uma proposta de automação deste processo por meio da utilização de dispositivos móveis e arquitetura SOA. Historicamente, os sistemas que utilizam arquiteturas orientadas a serviço não consideram fortemente as limitações inerentes aos dispositivos móveis, tais como poder de processamento, capacidade de armazenamento e duração da bateria. A falta de uma infra-estrutura de referência para estes sistemas pode ser apontada como uma das causas deste problema. Assim, é proposta uma infra-estrutura de desenvolvimento para sistemas móveis que utilizam uma arquitetura orientada a serviços voltada à experiência do usuário. Esta infra-estrutura tem especial atenção a como as restrições dos sistemas móveis influenciam tanto a arquitetura de software quanto a apresentação dos serviços para o usuário final. Disserta-se sobre fatores e questões relevantes ao projeto de sistemas de natureza móvel sugerindo a sua consideração durante a elaboração de projetos semelhantes. São propostos também um conjunto de métricas para avaliação do desempenho para a realização de experimentos com o objetivo de validar os aspectos de usabilidade e arquitetura, além de identificar modificações na infra-estrutura proposta.
Species distribution modeling system are used to identify regions where there is the probability to a species survive, based on the environmental characteristics where there is for sure presence of a species. Those systems require high performance computation due the large amount of data that are processed in order to create the distribution model. An important moment of the modeling process is the data collecting, when the researchers go field to identify the localizations of presence or absence, but this process is still done manually. This paper presents a proposal for automating this process through the use of mobile devices and SOA architecture. Historically, systems using service oriented architectures do not consider strongly the limitations of mobile devices such as processing power, storage capacity and duration of battery. The lack of an infrastructure of reference for these systems can be considered one of the causes of this problem. Thus, we propose an infrastructure development for mobile systems using a service-oriented architecture focused on user experience. This infrastructure has special attention to the restrictions of mobile systems influence both the software architecture as the presentation of services to the end user. Mobile related issues are discussed suggesting its consideration during the development of similar projects. Also, it is proposed a set of metrics for performance evaluation to carry out experiments aimed at validating the architecture and usability aspects, and identify changes in the proposed infrastructure.

Currently, smart mobile devices are used for more than just calling and texting. They can run complex applications such as GPS, antivirus, and photo editor applications. Smart devices today offer mobility, flexibility, and portability, but they have limited resources and a relatively weak battery. As companies began creating mobile resource intensive and power intensive applications, they have realized that cloud computing was one of the solutions that they could utilize to overcome smart device constraints. Cloud computing helps decrease memory usage and improve battery life. Mobile cloud computing is a current and expanding research area focusing on methods that allow smart mobile devices to take full advantage of cloud computing. Code offloading is one of the techniques employed in cloud computing with mobile devices. This research compares two dynamic offloading frameworks to determine which one is better in terms of execution time and battery life improvement.

Mobile applications are deployed in highly dynamic environments. Devices have limited resources available and the user context changes frequently. This introduces new requirements for applications, and requires that applications are able to adapt during runtime. In addition, developers must be able to incrementally add new behaviour to applications as required by unanticipated situations. Current approaches to mobile application development and architectures do not properly address these requirements of mobile applications. This work proposes a framework, based on coordination principles, which is able to facilitate the required methods of adaptation. The framework incorporates a methodology and an architecture. The architecture provides significant advantages over previous work in terms of adaptation support. The methodology provides developers with a development process and guidelines whereby adaptive applications may be specified. As new requirements of existing applications emerge, developers can build and deploy additions to applications during runtime. The research has been evaluated through the design of application prototypes. These were built through the use of an implemented toolkit for application development, which is based on the specified methodology. The architecture, methodology and toolkit provide a unifying framework for mobile applications. The work presented in this thesis closes a gap in existing knowledge in the design and execution of distributed mobile applications.

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Financiadora de Estudos e Projetos
The use of large displays for digital signage in collective spaces is increasing for numerous purposes. For most signalling scenarios, the dynamic adjustment of the display contents is desirable. Contextual information related to the site and to the signalling profile of observers may be taken into consideration for the selection of content and for user interaction. Interactions can occur implicitly and transparently, by just mutually identifying users and systems for the selection of the content displayed, or by allowing the explicit data exchange between users and the signalling system. Mobile computing devices and wireless technologies extend the possibilities of interaction with users, creating a complex scenario for the exhibition of public and private data. The dynamic analysis of contextual information, the retrieval and generation of presentation data, and the interaction with users all require significant processing which demonstrate the complexity of encoding a digital signage system. This thesis presents a distributed system and service-based software architecture developed for creating interactive digital signage systems. The architecture allows the centralized, but scalable, creation and management of digital signage systems containing different displays and users. An implementation of the proposed architectural model and software was carried out and the results show its ability to serve the creation of dynamic, flexible and interactive digital signage systems.
O uso de monitores de vídeo como forma de sinalização e apresentação de conteúdos digitais em ambientes de uso coletivo é crescente, com inúmeras finalidades. Além disso, para a maior parte dos cenários de sinalização, o ajuste dinâmico dos conteúdos a apresentar é algo desejável. Informações contextuais, relacionadas ao local de sinalização e ao perfil dos observadores, podem ser levadas em consideração para a seleção de conteúdos e para a interação com usuários. Interações podem ocorrer de forma implícita e transparente, apenas identificando usuários e sistemas mutuamente para a seleção do conteúdo exibido, ou permitindo a troca de dados explícita entre os usuários e o sistema de sinalização. Dispositivos computacionais móveis e tecnologias de comunicação sem fio ampliam as possibilidades de interação com usuários, criando um cenário complexo para exibição de dados públicos e privados. A análise dinâmica de parâmetros de contexto, a obtenção e a geração de conteúdos e a interação com usuários, contudo, requerem processamentos que evidenciam a complexidade da codificação de sistemas de sinalização digital. Este trabalho apresenta uma arquitetura de sistema distribuído e de software baseado em serviços, desenvolvida para a criação de sistemas de sinalização digital interativa. A arquitetura permite a criação e o gerenciamento centralizado, mas escalável, de sistemas de sinalização digital contendo diferentes pontos de apresentação e conjuntos de usuários. Uma implementação do modelo arquitetural e de software proposto foi realizada e os resultados mostram sua capacidade de atender à criação de sistemas de sinalização digital dinâmicos, flexíveis e interativos.

Thesis (Ph.D.)--Indiana University, Dept. of Computer Science, 2006.
"Title from dissertation home page (viewed July 11, 2007)." Source: Dissertation Abstracts International, Volume: 67-08, Section: B, page: 4529. Adviser: Geoffrey C. Fox.

Mobile devices such as smartphones and tablets have become ubiquitous in today's computing landscape. These devices have ushered in entirely new populations of users, and mobile operating systems are now outpacing more traditional "desktop" systems in terms of market share. The applications that run on these mobile devices (often referred to as "apps") have become a primary means of computing for millions of users and, as such, have garnered immense developer interest. These apps allow for unique, personal software experiences through touch-based UIs and a complex assortment of sensors. However, designing and implementing high quality mobile apps can be a difficult process. This is primarily due to challenges unique to mobile development including change-prone APIs and platform fragmentation, just to name a few. in this dissertation we develop techniques that aid developers in overcoming these challenges by automating and improving current software design and testing practices for mobile apps. More specifically, we first introduce a technique, called Gvt, that improves the quality of graphical user interfaces (GUIs) for mobile apps by automatically detecting instances where a GUI was not implemented to its intended specifications. Gvt does this by constructing hierarchal models of mobile GUIs from metadata associated with both graphical mock-ups (i.e., created by designers using photo-editing software) and running instances of the GUI from the corresponding implementation. Second, we develop an approach that completely automates prototyping of GUIs for mobile apps. This approach, called ReDraw, is able to transform an image of a mobile app GUI into runnable code by detecting discrete GUI-components using computer vision techniques, classifying these components into proper functional categories (e.g., button, dropdown menu) using a Convolutional Neural Network (CNN), and assembling these components into realistic code. Finally, we design a novel approach for automated testing of mobile apps, called CrashScope, that explores a given android app using systematic input generation with the intrinsic goal of triggering crashes. The GUI-based input generation engine is driven by a combination of static and dynamic analyses that create a model of an app's GUI and targets common, empirically derived root causes of crashes in android apps. We illustrate that the techniques presented in this dissertation represent significant advancements in mobile development processes through a series of empirical investigations, user studies, and industrial case studies that demonstrate the effectiveness of these approaches and the benefit they provide developers.

Computational offloading advances the deployment of Mobile Edge Computing (MEC) in the next generation communication networks. However, the distributed nature of the mobile users and the complex applications make it challenging to schedule the tasks reasonably among multiple devices. Therefore, by leveraging the idea of Software-Defined Networking (SDN) and Service Composition (SC), we propose a Software-Defined Service Composition model (SDSC). In this model, the SDSC controller is deployed at the edge of the network and composes service in a centralized manner to reduce the latency of the task execution and the traffic on the access links by satisfying the user-specific requirement. We formulate the low latency service composition as a Constraint Satisfaction Problem (CSP) to make it a user-centric approach. With the advent of the SDN, the global view and the control of the entire network are made available to the network controller which is further leveraged by our SDSC approach. Furthermore, the service discovery and the offloading of tasks are designed for MEC environment so that the users can have a complex and robust system. Moreover, this approach performs the task execution in a distributed manner. We also define the QoS model which provides the composition rule that forms the best possible service composition at the time of need. Moreover, we have extended our SDSC model to involve the constant mobility of the mobile devices. To solve the mobility issue, we propose a mobility model and a mobility-aware QoS approach enabled in the SDSC model. The experimental simulation results demonstrate that our approach can obtain better performance than the energy saving greedy algorithm and the random offloading approach in a mobile environment.

La croissance des appareils connectés, principalement due au grand nombre de déploiements de l'internet des objets et à l'émergence des services de cloud mobile, introduit de nouveaux défis pour la conception d'architectures de services dans le Cloud Computing Mobile (CCM) du cloud computing mobile. Nous montrons dans cette thèse comment l'architecture orientée services SOA peut être une solution clé pour fournir des services cloud mobiles distribués et comment la plate-forme OSGi peut être un cadre adaptatif et efficace pour fournir une telle implémentation. Nous adaptons le cadre CCM proposé à différents contextes d'architecture. Le premier est un modèle centré traditionnel, où les appareils mobiles sont réduits à consommer des services. Le second est un modèle distribué où la puissance de l'interaction de mobile à mobile offre des opportunités illimitées de services de valeur, et enfin, l'architecture à trois niveaux est considérée avec l'introduction de la notion de cloudlet. Pour chaque contexte, nous explorons la performance de notre cadre axé sur le service et le comparons à d'autres solutions existantes
The growth of connected devices, mostly due to the large number of internet of things IoT deployments and the emergence of mobile cloud services, introduces new challenges for the design of service architectures in mobile cloud computing MCC. An MCC framework should provide elasticity and scalability in a distributed and dynamic way while dealing with limited environment resources and variable mobile contexts web applications, real-time, enterprise services, mobile to mobile, hostile environment, etc. that may include additional constraints impacting the design foundation of cloud services. We show in this thesis how service-oriented architecture SOA can be a key solution to provide distributed mobile cloud services and how OSGi platform can be an adaptive and efficient framework to provide such implementation. We adapt the proposed MCC framework to different architecture contexts. The first one is a traditional centric model, where mobile devices are reduced to consuming services. The second one is a distributed model where the power of mobile-to-mobile interaction offers unlimited value-services opportunities, and finally, three-tier architecture is considered with the introduction of the cloudlet notion. For each context, we explore the performance of our service-oriented framework, and contrast it with alternative existing solutions

Doutoramento em Ciências da Computação
When developing software for autonomous mobile robots, one has to inevitably tackle some kind of perception. Moreover, when dealing with agents that possess some level of reasoning for executing their actions, there is the need to model the environment and the robot internal state in a way that it represents the scenario in which the robot operates. Inserted in the ATRI group, part of the IEETA research unit at Aveiro University, this work uses two of the projects of the group as test bed, particularly in the scenario of robotic soccer with real robots. With the main objective of developing algorithms for sensor and information fusion that could be used e ectively on these teams, several state of the art approaches were studied, implemented and adapted to each of the robot types. Within the MSL RoboCup team CAMBADA, the main focus was the perception of ball and obstacles, with the creation of models capable of providing extended information so that the reasoning of the robot can be ever more e ective. To achieve it, several methodologies were analyzed, implemented, compared and improved. Concerning the ball, an analysis of ltering methodologies for stabilization of its position and estimation of its velocity was performed. Also, with the goal keeper in mind, work has been done to provide it with information of aerial balls. As for obstacles, a new de nition of the way they are perceived by the vision and the type of information provided was created, as well as a methodology for identifying which of the obstacles are team mates. Also, a tracking algorithm was developed, which ultimately assigned each of the obstacles a unique identi er. Associated with the improvement of the obstacles perception, a new algorithm of estimating reactive obstacle avoidance was created. In the context of the SPL RoboCup team Portuguese Team, besides the inevitable adaptation of many of the algorithms already developed for sensor and information fusion and considering that it was recently created, the objective was to create a sustainable software architecture that could be the base for future modular development. The software architecture created is based on a series of di erent processes and the means of communication among them. All processes were created or adapted for the new architecture and a base set of roles and behaviors was de ned during this work to achieve a base functional framework. In terms of perception, the main focus was to de ne a projection model and camera pose extraction that could provide information in metric coordinates. The second main objective was to adapt the CAMBADA localization algorithm to work on the NAO robots, considering all the limitations it presents when comparing to the MSL team, especially in terms of computational resources. A set of support tools were developed or improved in order to support the test and development in both teams. In general, the work developed during this thesis improved the performance of the teams during play and also the e ectiveness of the developers team when in development and test phases.
Durante o desenvolvimento de software para robôs autónomos móveis, e inevitavelmente necessário lidar com algum tipo de perceção. Al em disso, ao lidar com agentes que possuem algum tipo de raciocínio para executar as suas ações, há a necessidade de modelar o ambiente e o estado interno do robô de forma a representar o cenário onde o robô opera. Inserido no grupo ATRI, integrado na unidade de investigação IEETA da Universidade de Aveiro, este trabalho usa dois dos projetos do grupo como plataformas de teste, particularmente no cenário de futebol robótico com robôs reais. Com o principal objetivo de desenvolver algoritmos para fusão sensorial e de informação que possam ser usados eficazmente nestas equipas, v arias abordagens de estado da arte foram estudadas, implementadas e adaptadas para cada tipo de robôs. No âmbito da equipa de RoboCup MSL, CAMBADA, o principal foco foi a perceção da bola e obstáculos, com a criação de modelos capazes de providenciar informação estendida para que o raciocino do robô possa ser cada vez mais eficaz. Para o alcançar, v arias metodologias foram analisadas, implementadas, comparadas e melhoradas. Em relação a bola, foi efetuada uma análise de metodologias de filtragem para estabilização da sua posição e estimação da sua velocidade. Tendo o guarda-redes em mente, foi também realizado trabalho para providenciar informação de bolas no ar. Quanto aos obstáculos, foi criada uma nova definição para a forma como são detetados pela visão e para o tipo de informação fornecida, bem como uma metodologia para identificar quais dos obstáculos são colegas de equipa. Além disso foi desenvolvido um algoritmo de rastreamento que, no final, atribui um identicador único a cada obstáculo. Associado a melhoria na perceção dos obstáculos foi criado um novo algoritmo para realizar desvio reativo de obstáculos. No contexto da equipa de RoboCup SPL, Portuguese Team, al em da inevitável adaptação de vários dos algoritmos j a desenvolvidos para fusão sensorial e de informação, tendo em conta que foi recentemente criada, o objetivo foi criar uma arquitetura sustentável de software que possa ser a base para futuro desenvolvimento modular. A arquitetura de software criada e baseada numa série de processos diferentes e métodos de comunicação entre eles. Todos os processos foram criados ou adaptados para a nova arquitetura e um conjunto base de papeis e comportamentos foi definido para obter uma framework funcional base. Em termos de perceção, o principal foco foi a definição de um modelo de projeção e extração de pose da câmara que consiga providenciar informação em coordenadas métricas. O segundo objetivo principal era adaptar o algoritmo de localização da CAMBADA para funcionar nos robôs NAO, considerando todas as limitações apresentadas quando comparando com a equipa MSL, principalmente em termos de recursos computacionais. Um conjunto de ferramentas de suporte foram desenvolvidas ou melhoradas para auxiliar o teste e desenvolvimento em ambas as equipas. Em geral, o trabalho desenvolvido durante esta tese melhorou o desempenho da equipas durante os jogos e também a eficácia da equipa de programação durante as fases de desenvolvimento e teste.

Ubiquitous computing describes a world in which technology invisibly assist us in our everyday activities. Unfortunately, development of ubiquitous software has fallen behind advances in available hardware and high-speed networking. Subiquitous is a software platform to support the development and deployment of applications in a ubiquitous computing environment. The goal of Subiquitous is to provide flexible support for a variety of ubiquitous application structures and distributions as well as to support the rapid development and zero configuration, user friendly set-up of those applications. The Subiquitous system consists of two basic parts. First, it provides a client-server architecture to support the deployment and communication of Subiquitous applications. Second, it provides an application framework used to build Subiquitous applications. The framework, in collaboration with the Subiquitous server and client, provides service discovery, transparent and flexible communications, code distribution, and application organization. To demonstrate Subiquitous contributions toward the improvement of ubiquitous software, a number of example ubiquitous applications were developed. The examples demonstrate: a) distribution of Subiquitous applications to different devices along the Model-View-Controller separation, b) running of the same application in multiple devices supporting easy communication between devices, c) a resource-server with multiple clients all sharing data from a single location, and d) an existing complex application with a Subiquitous wrapper that supports moving user interaction from one device to another. Each example application requires zero user configuration and includes no more than thirty lines of Subiquitous code to support user interaction across multiple devices in the home.
Master of Science

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

The presence of computer technologies in our daily life is growing by leaps and bounds. One of the recent trends is the use of mobile technologies and cloud services for supporting everyday tasks and the sharing of information between users. The field of education is not absent from these developments and many organizations are adopting Information and Communication Technologies (ICT) in various ways for supporting teaching and learning. The field of Mobile Learning (M-Learning) offers new opportunities for carrying out collaborative educational activities in a variety of settings and situations. The use of mobile technologies for enhancing collaboration provides new opportunities but at the same time new challenges emerge. One of those challenges is discussed in this thesis and it con- cerns with uncertainties related to the dynamic aspects that characterized outdoor M-Learning activities. The existence of these uncertainties force software developers to make assumptions in their developments. However, these uncertainties are the cause of risks that may affect the required outcomes for M-Learning activities. Mitigations mechanisms can be developed and included to reduce the risks’ impact during the different phases of development. However, uncertainties which are present at runtime require adaptation mechanisms to mitigate the resulting risks. This thesis analyzes the current state of the art in self-adaptation in Technology-Enhanced Learning (TEL) and M-Learning. The results of an extensive literature survey in the field and the outcomes of the Geometry Mobile (GEM) research project are reported. A list of uncertainties in collaborative M-Learning activities and the associated risks that threaten the critical QoS outcomes for collaboration are identified and discussed. A detailed elaboration addressing mitigation mechanisms to cope with these problems is elaborated and presented. The results of these efforts provide valuable insights and the basis towards the design of a multi-agent self-adaptive architecture for multiple concerns that is illustrated with a prototype implementation. The proposed conceptual architecture is an initial cornerstone towards the creation of a decentralized distributed self-adaptive system for multiple concerns to guarantee collaboration in M-Learning.

Software mobile agents is a new distributed computing paradigm which was developed to support efficient computing over the Internet. Since its inception there has been a significant research effort to produce concrete agent-based artefacts. This phenomenon resulted in the proliferation of a large number of agent systems, mostly based on proprietary programming languages, each with its own characteristics, peculiarities and assumptions. Hence the agent technology has largely remained hidden and incomprehensible by Internet end users. Moreover the issue of interoperability and integration of agents with existing legacy software has only just started to be addressed by the agent research community in a rather ad hoc way. In this thesis we attempt to design an agent architecture which is independent of any programming language and therefore is directly suitable for Internet end users. The proposed architecture, labelled as Mobile Agent System for Internet Computing (MASIC), addresses several important contemporary issues in agent research. It defines an agent as a container of reusable components that can be copied or moved to other agents. Each agent has a symmetric I/O access control module and is also equipped with associative access collaboration facilities. Additionally every agent contains a navigator module which stores the agent's itinerary plan and provides an interface via which the agent itself or other authorised agents can dynamically adapt the plan to reflect run-time events and constraints. The agent system provides an integrated access control architecture which enables an agent to define customised access control structures that can be fully or partially shared with other agents. Existing access control structures can be combined to create new structures that represent more complex access mechanisms. Agents can discover other agents offering pertinent services via an adaptive, customisable agent discovery architecture incorporated in MASIC. This discovery architecture enables the full interaction of links with queries and supports the definition of access paths which are tightly coupled with access control and. other customised services. MASIC also provides the conceptual architecture of a message-oriented agent communication system integrated with a mobility management scheme. Finally, this thesis presents the design and implementation of a prototype graphical interface which enables the potential user of the system to create, manage and interact with agents in real time. In conclusion the research presented in this thesis aims to provide a comprehensive, language-neutral, secure, collaborative environment within which mobile agents can interact with their peers in order to perform their tasks efficiently while human operators can oversee and manage these activities through a user friendly interface. The architecture is generic in nature as it can support general-purpose, agent-based computations. Its concepts, entities and mechanisms can be fully or partially re-used to provide architectural solutions to challenges in various application domains such as Knowledge Management, the GRID and E-Commerce.

COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
A computação ubíqua aliada ao avanço tecnológico de sensores definiu um novo cenário no qual a integração de diversos recursos computacionais pode contribuir para que um conjunto de serviços e funcionalidades esteja disponível ao usuário sempre que necessário. Um subconjunto desta área é de sistemas sensíveis às atividades realizadas por seus usuários, isto é, sistemas que utilizam informações sobre o que o usuário está fazendo. Nesses sistemas, mecanismos de inferência são essenciais para reconhecer ações do usuário e permitir que o comportamento do sistema se adapte a estas ações. Entretanto, como esses ambientes são caracterizados por uma elevada troca de informações, o desenvolvimento deste tipo de sistema não é uma tarefa trivial e possui como desafios: privacidade, desempenho, complexidade e ambigüidade das informações coletadas. O objetivo deste trabalho é propor uma arquitetura para sistemas de inferências de atividades do usuário. Para atingir esse objetivo, definimos um conjunto de componentes que representam funções especificas do processo de inferência. Com o objetivo de analisar a viabilidade da arquitetura proposta, desenvolvemos, avaliamos e relatamos um protótipo de sistema baseado na arquitetura.
The ubiquitous computing combined with the advance of sensor technology creates a scenario in which the integration of several computing resources is used to keep a set of services and features available to the user whenever necessary. A particular trend in this area is the activity based systems, i.e., systems that are aware of the activity played by the user. In these systems, inference engine is essential to recognize user’s actions and allow the systems to adapt its behavior according to user’s actions. Though, the development of this type of systems is not a trivial task as the high rate of information exchanged brings challenges related to privacy, performance and information management. In this work we propose an architecture for activity inference systems. To achieve this goal, we define a set of components that perform important roles in the inference process. Finally, to show the feasibility of this approach, we designed, implemented and evaluated a system based on the proposed architecture.

With the deployment of Long Term Evolution (LTE) networks, mobile networks will become an important infrastructure component in the cloud ecosystem.  However, in the cloud computing era, traditional routing and switching platforms do not meet the requirements of this new trend, especially in a mobile network environment. With the recent advances in software switches and efficient virtualization using commodity servers, Software Defined Networking (SDN) has emerged as a powerful technology to meet the new requirements for supporting a new generation of cloud service. This thesis describers an experimental investigation of cloud computing, SDN, and a mobile network’s packet core. The design of a mobile network exploiting the evolution of SDN is also presented. The actual implementation consists of a GTP enabled Open vSwitch together with the transparent mode of mobile network SDN evolution. Open vSwitch is a SDN product designed for computer networks. The implementation extends Open vSwitch with an implementation of the GTP protocol. This extension enables Open vSwitch to be an excellent SDN component for mobile networks. In transparent mode, a cloud data center is deployed without making any modification to the existing mobile networks.  In the practical evaluation of the GTP-U tunnel protocol implementation, the measured metrics are UDP and TCP throughput, end-to-end latency and jitter.  Two experiments have been conducted and described in the evaluation chapter. Cloud computing has become one of the hottest Internet topics. It is attractive for the mobile network to adopt cloud computing technology in order to enjoy the benefits of cloud computing. For example, to reduce network construction cost, make the network deployment more flexible, etc. This thesis presents an potential direction for mobile network cloud computing. Since this thesis relies on open source projects, readers may use the results to explore a feasible direction for mobile network cloud computing evolution.
Med utbyggnaden av långa (LTE) Term Evolution nätverk, mobila nätverk kommer blivit en viktig infrastruktur komponent i molnet ekosystemet. Men i cloud computing eran, uppfyller traditionella routing och switching plattformar inte kraven i denna nya trend, särskilt i ett mobilnät miljö. Med de senaste framstegen i programvara växlar och effektiv virtualisering påråvaror servrar, programvarustyrd Nätverk (SDN) har utvecklats till en kraftfull teknik för att möta de nya kraven för att stödja en ny generation av molntjänst. Denna avhandling beskrivarna en försöksverksamhet inriktad undersökning av cloud computing, SDN och ett mobilnät är Packet Core. Utformningen av ett mobilnät utnyttja SDN utveckling presenteras också. Det faktiska genomförandet består av en GTP aktiverad Open Vswitch tillsammans med transparent läge av mobilnätet SDN evolution. Öppna Vswitch är en SDN-produkt avsedd för datornätverk. Genomförandet utökar Open Vswitch med en implementering av GTP-protokollet. Denna uppgradering gör Open Vswitch vara som en utmärkt SDN komponent för mobila nätverk. I transparent läge är ett moln datacenter utplacerade utan göra eventuella ändringar till befintliga mobilnät. I den praktiska utvärderingen av GTP-U tunnel protokollimplementering, de uppmätta mått är UDP och TCP genomströmning, end-to-end-latens, jitter och paketförluster.  Tvåexperiment har utförts i utvärderingen kapitlet. Cloud computing har blivit en av de hetaste av Internet. Således kan framtiden för det mobila nätet ocksåanta teknik cloud computing och dra nytta av cloud computing. Till exempel minska kostnaderna nätbyggnad, gör nätverket distribuera mer flexibla, etc. .. Denna avhandling presenterar en möjlig inriktning för mobilnät cloud computing. Eftersom denna avhandling bygger påopen source-projekt, läsarna använda resultatet av den att utforska möjliga riktning mobilnät cloud computing utveckling.

One recent advance in software technology is the development of software agents that can adapt to changes in their environment and can cooperate and coordinate their activities to complete a given task. Such agents can be distributed over a network. Advances in hardware technology have meant that clusters of workstations can be used to create parallel virtual machines that bring the power of parallel computing to a much wider research and development community. Many software packages are now being developed to utilise such cluster environments. In a cluster, each processor will be multitasking and running other jobs simultaneously with a distributed application that uses a message passing environment such as MPI. A typical application might be a large scale mesh-based computation, such as a finite element code, in which load balancing is equivalent to mesh partitioning. When the load is varying between processors within the cluster, distributing the computation in equal amounts may not deliver the optimum performance. Some machines may be very heavily loaded by other users while other processors may have no such additional load. It may be beneficial to measure current system information and use this information when balancing the load within a single distributed application program. This thesis presents one approach to distributing workload more efficiently in a multi-user distributed environment by using mobile agents to collect system information which is then transmitted to all the MPI tasks. The thesis contains a review of software agents and mesh partitioning together with some numerical experiments and a paper.

Military work-practice is a difficult area of research where paper-based approaches are still extended. This thesis proposes a solution which permits the digitalization of information at the same time as workpractice remains unaltered for soldiers working with maps in the field. For this purpose, a mobile interactive paper-based platform has been developed which permits the users to maintain their current work-flow. The premise of the solution parts from a system consisting of a prepared paper-map, a cellular phone, a desktop computer, and a digital pen with bluetooth connection. The underlying idea is to permit soldiers to take advantage of the information a computerized system can offer, at the same time as the overhead it incurs is minimized. On one hand this implies that the solution must be light-weight, on the other it must retain current working procedures as far as possible. The desktop computer is used to develop new paper-driven applications through the application provided in the development framework, thus allowing the tailoring of applications to the changing needs of military operations. One major component in the application suite is a symbol recognizer which is capable of recognizing symbols parting from a template which can be created in one of the applications. This component permits the digitalization of information in the battlefield by drawing on the paper-map. The proposed solution has been found to be viable, but still there is a need for further development. Furthermore, there is a need to adapt the existing hardware to the requirements of the military to make it usable in a real-world situation.

We are witnessing exponential growth in the number of powerful, multiply-connected, energy-rich stationary and mobile nodes, which will make available a massive pool of computing and communication resources. We claim that cloud computing can provide resilient on-demand computing, and more effective and efficient utilization of potentially infinite array of resources. Current cloud computing systems are primarily built using stationary resources. Recently, principles of cloud computing have been extended to the mobile computing domain aiming to form local clouds using mobile devices sharing their computing resources to run cloud-based services. However, current cloud computing systems by and large fail to provide true on-demand computing due to their lack of the following capabilities: 1) providing resilience and autonomous adaptation to the real-time variation of the underlying dynamic and scattered resources as they join or leave the formed cloud; 2) decoupling cloud management from resource management, and hiding the heterogeneous resource capabilities of participant nodes; and 3) ensuring reputable resource providers and preserving the privacy and security constraints of these providers while allowing multiple users to share their resources. Consequently, systems and consumers are hindered from effectively and efficiently utilizing the virtually infinite pool of computing resources. We propose a platform for mobile cloud computing that integrates: 1) a dynamic real-time resource scheduling, tracking, and forecasting mechanism; 2) an autonomous resource management system; and 3) a cloud management capability for cloud services that hides the heterogeneity, dynamicity, and geographical diversity concerns from the cloud operation. We hypothesize that this would enable 'Collaborative Computing Cloud (C3)' for on-demand computing, which is a dynamically formed cloud of stationary and/or mobile resources to provide ubiquitous computing on-demand. The C3 would support a new resource-infinite computing paradigm to expand problem solving beyond the confines of walled-in resources and services by utilizing the massive pool of computing resources, in both stationary and mobile nodes. In this dissertation, we present a C3 management platform, named PlanetCloud, for enabling both a new resource-infinite computing paradigm using cloud computing over stationary and mobile nodes, and a true ubiquitous on-demand cloud computing. This has the potential to liberate cloud users from being concerned about resource constraints and provides access to cloud anytime and anywhere. PlanetCloud synergistically manages 1) resources to include resource harvesting, forecasting and selection, and 2) cloud services concerned with resilient cloud services to include resource provider collaboration, application execution isolation from resource layer concerns, seamless load migration, fault-tolerance, the task deployment, migration, revocation, etc. Specifically, our main contributions in the context of PlanetCloud are as follows. 1. PlanetCloud Resource Management • Global Resource Positioning System (GRPS): Global mobile and stationary resource discovery and monitoring. A novel distributed spatiotemporal resource calendaring mechanism with real-time synchronization is proposed to mitigate the effect of failures occurring due to unstable connectivity and availability in the dynamic mobile environment, as well as the poor utilization of resources. This mechanism provides a dynamic real-time scheduling and tracking of idle mobile and stationary resources. This would enhance resource discovery and status tracking to provide access to the right-sized cloud resources anytime and anywhere. • Collaborative Autonomic Resource Management System (CARMS): Efficient use of idle mobile resources. Our platform allows sharing of resources, among stationary and mobile devices, which enables cloud computing systems to offer much higher utilization, resulting in higher efficiency. CARMS provides system-managed cloud services such as configuration, adaptation and resilience through collaborative autonomic management of dynamic cloud resources and membership. This helps in eliminating the limited self and situation awareness and collaboration of the idle mobile resources. 2. PlanetCloud Cloud Management Architecture for resilient cloud operation on dynamic mobile resources to provide stable cloud in a continuously changing operational environment. This is achieved by using trustworthy fine-grained virtualization and task management layer, which isolates the running application from the underlying physical resource enabling seamless execution over heterogeneous stationary and mobile resources. This prevents the service disruption due to variable resource availability. The virtualization and task management layer comprises a set of distributed powerful nodes that collaborate autonomously with resource providers to manage the virtualized application partitions.
Ph. D.

We extend the Jinni mobile agent architecture with a multicast network transport layer, an agent-to-agent delegation mechanism and a reflection based Prolog-to-Java interface. To ensure that our agent infrastructure runs efficiently, independently of router-level multicast support, we describe a blackboard based algorithm for locating a randomly roaming agent. As part of the agent-to-agent delegation mechanism, we describe an alternative to code-fetching mechanism for stronger mobility of mobile agents with less network overhead. In the context of direct and reflection based extension mechanisms for Jinni, we describe the design and the implementation of a reflection based Prolog-to-Java interface. The presence of subtyping and method overloading makes finding the most specific method corresponding to a Prolog call pattern fairly difficult. We describe a run-time algorithm which provides accurate handling of overloaded methods beyond Java's reflection package's limitations.

Master of Philosophy (Architecture)
Context-aware computing is a mobile computing paradigm in which applications can discover, use, and take advantage of contextual information, such as the location, tasks and preferences of the user, in order to adapt their behaviour in response to changing operating environments and user requirements. A problem that arises is the inability to respond to contextual information that cannot be classified into any known context. Many context-aware applications require all discovered contextual information to exactly match a type of context, otherwise the application will not react responsively. The ability to learn and recall contexts based on the contextual information discovered has not been very well addressed by previous context-aware applications and research. The aim of this thesis is to develop a component middleware technology for mobile computing devices for the discovery and capture of contextual information, using the situated reasoning concept of constructive memory. The research contribution of this thesis lies in developing a modified architecture for context-aware systems, using a constructive memory model as a way to learn and recall contexts from previous experiences and application interactions. Using a constructive memory model, previous experiences can be induced to construct potential contexts, given a small amount of learning and interaction. The learning process is able to map the many variations of contextual information currently discovered by the user with a predicted type of context based on what the application has stored and seen previously. It only requires a small amount of contextual information to predict a context, something common context-aware systems lack, as they require all information before a type of context is assigned. Additionally, some mechanism to reason about the contextual information being discovered from past application interactions will be beneficial to induce contexts for future experiences.

Mobile cloud computing is an emerging field of research that aims to provide a platform on which intelligent and feature-rich applications are delivered to the user at any time and at anywhere. Computation offload between mobile and cloud plays a key role in this vision and ensures that the integration between mobile and cloud is both seamless and energy-efficient. In this thesis, we develop a suite of energy-aware workload offloading frameworks to accommodate the efficient execution of mobile workflows on a mobile cloud platform. We start by looking at two energy objectives of a mobile cloud platform. While the first objective aims at minimising the overall energy cost of the platform, the second objective aims at the longevity of the platform taking into account the residual battery power of each device. We construct optimisation models for both objectives and develop two efficient algorithms to approximate the optimal solution. According to simulation results, our greedy autonomous offload (GAO) algorithm is able to efficiently produce allocation schemes that are close to optimal. Next, we look at the task allocation problem from a workflow's perspective and develop energy-aware offloading strategies for time-constrained mobile workflows. We demonstrate the effect of software and hardware characteristics have over the offload-efficiency of mobile workflows with a workflow-oriented greedy autonomous offload (WGAO) algorithm, an extension to the GAO algorithm. Thirdly, we propose a novel network I-O model to describe the bandwidth dependencies and allocation problem in mobile networks. This model lays the foundation for further objective developments such as the cost-based and adaptive bandwidth allocation schemes which we also present in this thesis. Lastly, we apply a game theoretical approach to model the non-cooperative behaviour of mobile cloud applications that reside on the same device. Mixed-strategy Nash equilibrium is derived for the offload game which further quantifies the price of anarchy of the system.

International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California
An increasing need among telemetry data analysts for new mechanisms for efficient access to high-speed data in distributed environments has led BBN to develop a new architecture for data analysis. The data sets of concern can be from either real-time or post-test sources. This architecture consists of an expandable suite of tools based upon a data distribution software "backbone" which allows the interchange of high volume data streams among server processes and client workstations. One benefit of this architecture is that it allows one to assemble software systems from a set of off-the-shelf, interoperable software modules. This modularity and interoperability allows these systems to be configurable and customizable, while requiring little applications programming by the system integrator.

In mobile cloud computing (MCC), rich mobile application data is processed at the cloud infrastructure by reliving resource limited mobile devices from computationally complex tasks. However, due to the ubiquitous and mobility nature, providing time critical rich applications over remote cloud infrastructure is a challenging task for mobile application service providers. Therefore, according to the literature, close proximity placement of cloud services has been identified as a way to achieve lower end-to-end access delay and thereby provide a higher quality of experience (QoE) for rich mobile application users. However, providing a higher Quality of Service (QoS) with mobility is still a challenge within close proximity clouds. Access delay to a closely placed cloud tends to be increased over time when users move away from the cloud. However, reactive resource relocation mechanism proposed in literature does not provide a comprehensive mechanism to guarantee the QoS and as well as to minimize service provisioning cost for mobile cloud service providers. As a result, using the benefits of SDN and the data plane programmability with logically centralized controllers, a resource allocation framework was proposed for IaaS mobile clouds with regional datacenters. The user mobility problem was analyzed within SDN-enabled wireless networks and addressed the possible service level agreement violations that could occur with inter-regional mobility. The proposed framework is composed of an optimization algorithm to provide seamless cloud service during user mobility. Further a service provisioning cost minimization criteria was considered during an event of resource allocation and inter-regional user mobility.

This dissertation studies the context-aware application with its proposed algorithms at client side. The required context-aware infrastructure is discussed in depth to illustrate that such an infrastructure collects the mobile user’s context information, registers service providers, derives mobile user’s current context, distributes user context among context-aware applications, and provides tailored services. The approach proposed tries to strike a balance between the context server and mobile devices. The context acquisition is centralized at the server to ensure the usability of context information among mobile devices, while context reasoning remains at the application level. Hence, a centralized context acquisition and distributed context reasoning are viewed as a better solution overall. The context-aware search application is designed and implemented at the server side. A new algorithm is proposed to take into consideration the user context profiles. By promoting feedback on the dynamics of the system, any prior user selection is now saved for further analysis such that it may contribute to help the results of a subsequent search. On the basis of these developments at the server side, various solutions are consequently provided at the client side. A proxy software-based component is set up for the purpose of data collection. This research endorses the belief that the proxy at the client side should contain the context reasoning component. Implementation of such a component provides credence to this belief in that the context applications are able to derive the user context profiles. Furthermore, a context cache scheme is implemented to manage the cache on the client device in order to minimize processing requirements and other resources (bandwidth, CPU cycle, power). Java and MySQL platforms are used to implement the proposed architecture and to test scenarios derived from user’s daily activities. To meet the practical demands required of a testing environment without the impositions of a heavy cost for establishing such a comprehensive infrastructure, a software simulation using a free Yahoo search API is provided as a means to evaluate the effectiveness of the design approach in a most realistic way. The integration of Yahoo search engine into the context-aware architecture design proves how context aware application can meet user demands for tailored services and products in and around the user’s environment. The test results show that the overall design is highly effective,providing new features and enriching the mobile user’s experience through a broad scope of potential applications.

Tese (doutorado)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Ciência da Computação, 2014.
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A computação em nuvem tem sido considerada como uma opção para executar aplicações de alto desempenho. Entretanto, enquanto as plataformas de alto desempenho tradicionais como grid e supercomputadores oferecem um ambiente estável quanto à falha, desempenho e número de recursos, a computação em nuvem oferece recursos sob demanda, geralmente com desempenho imprevisível à baixo custo financeiro. Além disso, em ambiente de nuvem, as falhas fazem parte da sua normal operação. No entanto, as nuvens podem ser combinadas, criando uma federação, para superar os limites de uma nuvem muitas vezes com um baixo custo para os usuários. A federação de nuvens pode ajudar tanto os provedores quanto os usuários das nuvens a atingirem diferentes objetivos tais como: reduzir o tempo de execução de uma aplicação, reduzir o custo financeiro, aumentar a disponibilidade do ambiente, reduzir o consumo de energia, entre outros. Por isso, a federação de nuvens pode ser uma solução elegante para evitar o sub-provisionamento de recursos ajudando os provedores a reduzirem os custos operacionais e a reduzir o número de recursos ativos, que outrora ficariam ociosos consumindo energia, por exemplo. No entanto, a federação de nuvens aumenta as opções de recursos disponíveis para os usuários, requerendo, em muito dos casos, conhecimento em administração de sistemas ou em computação em nuvem, bem como um tempo considerável para aprender sobre as opções disponíveis. Neste contexto, surgem algumas questões, tais como: (a) qual dentre os recursos disponíveis é apropriado para uma determinada aplicação? (b) como os usuários podem executar suas aplicações na nuvem e obter um desempenho e um custo financeiro aceitável, sem ter que modificá-las para atender as restrições do ambiente de nuvem? (c) como os usuários não especialistas em nuvem podem maximizar o uso da nuvem, sem ficar dependente de um provedor? (d) como os provedores podem utilizar a federação para reduzir o consumo de energia dos datacenters e ao mesmo tempo atender os acordos de níveis de serviços? A partir destas questões, este trabalho apresenta uma solução para consolidação de aplicações em nuvem federalizadas considerando os acordos de serviços. Nossa solução utiliza um sistema multi-agente para negociar a migração das máquinas virtuais entres as nuvens. Simulações mostram que nossa abordagem pode reduzir em até 46% o consumo de energia e atender os requisitos de qualidade. Nós também desenvolvemos e avaliamos uma solução para executar uma aplicação de bioinformática em nuvens federalizadas, a custo zero. Nesse caso, utilizando a federação, conseguimos diminuir o tempo de execução da aplicação em 22,55%, considerando o seu tempo de execução na melhor nuvem. Além disso, este trabalho apresenta uma arquitetura chamada Excalibur, que possibilita escalar a execução de aplicações comuns em nuvem. Excalibur conseguiu escalar automaticamente a execução de um conjunto de aplicações de bioinformática em até 11 máquinas virtuais, reduzindo o tempo de execução em 63% e o custo financeiro em 84% quando comparado com uma configuração definida pelos usuários. Por fim, este trabalho apresenta um método baseado em linha de produto de software para lidar com as variabilidades dos serviços oferecidos por nuvens de infraestrutura (IaaS), e um sistema que utiliza deste processo para configurar o ambiente e para lidar com falhas de forma automática. O nosso método utiliza modelo de feature estendido com atributos para descrever os recursos e para selecioná-los com base nos objetivos dos usuários. Experimentos realizados com dois provedores diferentes mostraram que utilizando o nosso processo, os usuários podem executar as suas aplicações em um ambiente de nuvem federalizada, sem conhecer as variabilidades e limitações das nuvens. _______________________________________________________________________________________ ABSTRACT
Cloud computing has been seen as an option to execute high performance computing (HPC) applications. While traditional HPC platforms such as grid and supercomputers offer a stable environment in terms of failures, performance, and number of resources, cloud computing offers on-demand resources generally with unpredictable performance at low financial cost. Furthermore, in cloud environment, failures are part of its normal operation. To overcome the limits of a single cloud, clouds can be combined, forming a cloud federation often with minimal additional costs for the users. A cloud federation can help both cloud providers and cloud users to achieve their goals such as to reduce the execution time, to achieve minimum cost, to increase availability, to reduce power consumption, among others. Hence, cloud federation can be an elegant solution to avoid over provisioning, thus reducing the operational costs in an average load situation, and removing resources that would otherwise remain idle and wasting power consumption, for instance. However, cloud federation increases the range of resources available for the users. As a result, cloud or system administration skills may be demanded from the users, as well as a considerable time to learn about the available options. In this context, some questions arise such as: (a) which cloud resource is appropriate for a given application? (b) how can the users execute their HPC applications with acceptable performance and financial costs, without needing to re-engineer the applications to fit clouds’ constraints? (c) how can non-cloud specialists maximize the features of the clouds, without being tied to a cloud provider? and (d) how can the cloud providers use the federation to reduce power consumption of the clouds, while still being able to give service-level agreement (SLA) guarantees to the users? Motivated by these questions, this thesis presents a SLA-aware application consolidation solution for cloud federation. Using a multi-agent system (MAS) to negotiate virtual machine (VM) migrations between the clouds, simulation results show that our approach could reduce up to 46% of the power consumption, while trying to meet performance requirements. Using the federation, we developed and evaluated an approach to execute a huge bioinformatics application at zero-cost. Moreover, we could decrease the execution time in 22.55% over the best single cloud execution. In addition, this thesis presents a cloud architecture called Excalibur to auto-scale cloud-unaware application. Executing a genomics workflow, Excalibur could seamlessly scale the applications up to 11 virtual machines, reducing the execution time by 63% and the cost by 84% when compared to a user’s configuration. Finally, this thesis presents a software product line engineering (SPLE) method to handle the commonality and variability of infrastructure-as-a-service (IaaS) clouds, and an autonomic multi-cloud architecture that uses this method to configure and to deal with failures autonomously. The SPLE method uses extended feature model (EFM) with attributes to describe the resources and to select them based on the users’ objectives. Experiments realized with two different cloud providers show that using the proposed method, the users could execute their application on a federated cloud environment, without needing to know the variability and constraints of the clouds. _______________________________________________________________________________________ RÉSUMÉ
Le cloud computing a été considéré comme une option pour exécuter des applications de calcul haute performance (HPC). Bien que les plateformes traditionnelles de calcul haute performance telles que les grilles et les supercalculateurs offrent un environnement stable du point de vue des défaillances, des performances, et de la taille des ressources, le cloud computing offre des ressources à la demande, généralement avec des performances imprévisibles mais à des coûts financiers abordables. En outre, dans un environnement de cloud, les défaillances sont perçues comme étant ordinaires. Pour surmonter les limites d’un cloud individuel, plusieurs clouds peuvent être combinés pour former une fédération de clouds, souvent avec des coûts supplémentaires légers pour les utilisateurs. Une fédération de clouds peut aider autant les fournisseurs que les utilisateurs à atteindre leurs objectifs tels la réduction du temps d’exécution, la minimisation des coûts, l’augmentation de la disponibilité, la réduction de la consummation d’énergie, pour ne citer que ceux-là. Ainsi, la fédération de clouds peut être une solution élégante pour éviter le sur-approvisionnement, réduisant ainsi les coûts d’exploitation en situation de charge moyenne, et en supprimant des ressources qui, autrement, resteraient inutilisées et gaspilleraient ainsi de énergie. Cependant, la fédération de clouds élargit la gamme des ressources disponibles. En conséquence, pour les utilisateurs, des compétences en cloud computing ou en administration système sont nécessaires, ainsi qu’un temps d’apprentissage considérable pour maîtrises les options disponibles. Dans ce contexte, certaines questions se posent : (a) Quelle ressource du cloud est appropriée pour une application donnée ? (b) Comment les utilisateurs peuvent-ils exécuter leurs applications HPC avec un rendement acceptable et des coûts financiers abordables, sans avoir à reconfigurer les applications pour répondre aux norms et contraintes du cloud ? (c) Comment les non-spécialistes du cloud peuvent-ils maximiser l’usage des caractéristiques du cloud, sans être liés au fournisseur du cloud ? et (d) Comment les fournisseurs de cloud peuvent-ils exploiter la fédération pour réduire la consommation électrique, tout en étant en mesure de fournir un service garantissant les normes de qualité préétablies ? À partir de ces questions, la presente thèse propose une solution de consolidation d’applications pour la fédération de clouds qui garantit le respect des normes de qualité de service. On utilise un système multi-agents (SMA) pour négocier la migration des machines virtuelles entre les clouds. Les résultats de simulations montrent que notre approche pourrait réduire jusqu’à 46% la consommation totale d’énergie, tout en respectant les exigencies de performance. En nous basant sur la fédération de clouds, nous avons développé et évalué une approche pour exécuter une énorme application de bioinformatique à coût zéro. En outre, nous avons pu réduire le temps d’exécution de 22,55% par rapport à la meilleure exécution dans un cloud individuel. Cette thèse présente aussi une architecture de cloud baptisée « Excalibur » qui permet l’adaptation automatique des applications standards pour le cloud. Dans l’exécution d’une chaîne de traitements de la génomique, Excalibur a pu parfaitement mettre à l’échelle les applications sur jusqu’à 11 machines virtuelles, ce qui a réduit le temps d’exécution de 63% et le coût de 84% par rapport à la configuration de l’utilisateur. Enfin, cette thèse présente un processus d’ingénierie des lignes de produits (PLE) pour gérer la variabilité de l’infrastructure à la demande du cloud, et une architecture multi-cloud autonome qui utilise ce processus pour configurer et faire face aux défaillances de manière indépendante. Le processus PLE utilise le modele étendu de fonction (EFM) avec des attributs pour décrire les ressources et les sélectionner en fonction dês objectifs de l’utilisateur. Les expériences réalisées avec deux fournisseurs de cloud différents montrent qu’em utilisant le modèle proposé, les utilisateurs peuvent exécuter leurs applications dans un environnement de clouds fédérés, sans avoir besoin de connaître les variabilités et contraintes du cloud.

In current mobile telecommunication networks, databases and the subscriber data is distributed among multiple network domains and database systems. The heterogeneous data storage concept is based on the permanent evolution of the mobile networks and the support of different kinds of network technologies. Dependent on the particular network domain and the dedicated technology, distributed subscriber data has to be accessed via specialised protocols.This thesis proposes a novel software architecture for the next generation profile register (NGPR) - an approach to provide subscriber information using a logically centralised register for subscriber data from several mobile network domains. The NGPR subscriber data model supports a network-independent layer that references to different kinds of network-specific data (such as subscribed services, user related data and run-time data). Appropriate adapters ensure the reusage of network-independent data for several specific mobile core domains or administrative systems. This thesis includes an UMTS interoperability concept for the SS7 (signaling system no. 7) and IP-based domains by utilising the service-oriented architecture (SOA). SOA concepts provide the flexibility to integrate different network-specific domains by data services. The data services (based on web services technology) are supported in a conventional way and by a binary mode in order to improve performance for the telecommunication networks. The service framework of the NGPR manages data services in general and links requests from the mobile domains to relevant subsets of subscriber data. NGPR data services support network-specific and generic interfaces that are proposed within concepts of the next generation networks or UMTS release 6. Based on SOA, the NGPR architecture provides subscriber data convergence and simplified data access. Therefore, several specialised and generic network domains can be directly supported by the network-independent layer of the NGPR. Especially administrative systems and network nodes of closed domains are supposed to take advantage of the interoperability concept and the converged data of the NGPR.

In the context of software engineering for image processing (IP), we consider the notion of reusability of algorithms. In many software tools, an algorithm's implementation often depends on the type of processed data. In a broad definition, discrete digital images may have various forms : classical 2D images, 3D volumes, non-regular graphs, cell complexes, and so on : thus leading to a combinatorial explosion of the theoretical number of implementations. Generic programming (GP) is a framework suited to the development of reusable software tools. We present a programming paradigm based on GP designed for the creation of scientific software such as IP tools. This approach combines the benefits of reusability, expressive power, extensibility, and efficiency. We then propose a software architecture for IP using this programming paradigm based on a generic IP library. The foundations of this framework define essential IP concepts, enabling the development of algorithms compatible with many image types. We finally present a strategy to build high-level tools on top of this library, such as bridges to dynamic languages or graphical user interfaces. This mechanism has been designed to preserve the genericity and efficiency of the underlying software tools, while making them simpler to use and more flexible

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Electrotécnica
This dissertation presents a software architecture called the Distributed Software Architecture for Autonomous Robots (DSAAR), which is designed to provide the fast development and prototyping of multi-robot systems. The DSAAR building blocks allow engineers to focus on the behavioural model of robots and collectives. This architecture is of special interest in domains where several human, robot, and software agents have to interact continuously. Thus, fast prototyping and reusability is a must. DSAAR tries to cope with these requirements towards an advanced solution to the n-humans and m-robots problem with a set of design good practices and development tools. This dissertation will also focus on Human-Robot Interaction, mainly on the subject of teleoperation. In teleoperation human judgement is an integral part of the process, heavily influenced by the telemetry data received from the remote environment. So the speed in which commands are given and the telemetry data is received, is of crucial importance. Using the DSAAR architecture a teleoperation approach is proposed. This approach was designed to provide all entities present in the network a shared reality, where every entity is an information source in an approach similar to the distributed blackboard. This solution was designed to accomplish a real time response, as well as, the completest perception of the robots’ surroundings. Experimental results obtained with the physical robot suggest that the system is able to guarantee a close interaction between users and robot.

The Govan Mbeki Mathematics Development Unit (GMMDU) provides additional mathematics content to learners via mathematics workshops and DVDs. Mathematics is presented in PPT format. The prominence of feature phone usage has been confirmed amongst learners in socio-economic disadvantaged schools, specifically those learners participating in the GMMDU mathematics workshops. Feature phones typically contain limited device resources such as memory, battery power, and network resources. Distributed computing provides the potential to facilitate a new class of mobile applications with the provision of off-device resources. The objective of this research was the design of an architecture using Cloud Computing for the provision of mathematics in the form of PPT slides to feature phones. The capabilities of typical feature phones were reviewed as well as various distributed computing architectures that demonstrate potential benefit to the mobile environment. An Architecture using Cloud Computing for Content Provision (AC3P) was subsequently designed and applied as a proof of concept to facilitate the provision of mathematics in the form of PPT slides to feature phones. The application of AC3P was evaluated for efficiency and effectiveness. It was demonstrated that the application of AC3P provided efficient and effective provision of PPT to feature phones. The successful application of AC3P provided evidence that Cloud Computing may be used to facilitate the provision of mathematics content to feature phones. It is evident that AC3P may be applied in domains other than the provision of mathematics.

New technologies related to mobility, such as smartphones and tablets, once again push companies to reconsider their IT system. New services can be provided externally (to customers, partners or the general public) as well as internally (to employees) and existing ones have to be reconsidered to fit new devices and new ways of using IT. This important evolution implies that new technologies and new components are integrated in the IT system. Those components are characterized by a high volatility: they are subject to trend effects, they evolve quickly to follow the terminals market and thus their lifetime is far from guaranteed. This study focuses on new uses brought by mobile technologies and that modern companies can benefit from, and then, based on several market products, proposes a set of software architecture patterns that correspond to the different possible implementation of mobility in the IT system.

Current technologies for creating distributed simulations or virtual environments are too limited in terms of scalability and flexibility, particularly in the areas of network saturation, distribution of VR scenes, and co-ordination of large systems of active objects. This thesis proposes the use of mobile and distributed computing technology to alleviate some of these limitations. A study of contemporary technologies for distributed simulation and networked virtual environments has been made, examining the benefits and drawbacks of different techniques. The main theory that has been investigated is that processing of a global simulation space should be spread over a network of computers, the principle of locality cutting the network bandwidth required. Using a prototype language for distributed graph processing, which fully supports mobile programming, experimental systems have been developed to demonstrate the use of distributed processing in creating large-scale virtual environments. The working examples created show that the ideas proposed for distribution of interactive virtual environments are valid, and that mobile programming techniques provide a new direction of development for the field of simulation. A more detailed summary of the work is given in Appendix D. Five publications to date (shown overleaf) have resulted from my involvement in the work, and a number of others have resulted from the overall project.

The major motivation for self-adaptive computing systems is the self-adjustment of the software according to a changing environment. Adaptive computing systems can add, remove, and replace their own components in response to changes in the system itself and in the operating environment of a software system. Although these systems may provide a certain degree of confidence against new environments, their structural and behavioral changes should be validated after adaptation occurs at runtime. Testing dynamically adaptive systems is extremely challenging because both the structure and behavior of the system may change during its execution. After self adaptation occurs in autonomic software, new components may be integrated to the software system. When new components are incorporated, testing them becomes vital phase for ensuring that they will interact and behave as expected. When self adaptation is about removing existing components, a predefined test set may no longer be applicable due to changes in the program structure. Investigating techniques for dynamically updating regression tests after adaptation is therefore necessary to ensure such approaches can be applied in practice. We propose a model-driven approach that is based on change propagation for synchronizing a runtime test model for a software system with the model of its component structure after dynamic adaptation. A workflow and meta-model to support the approach was provided, referred to as Test Information Propagation (TIP). To demonstrate TIP, a prototype was developed that simulates a reductive and additive change to an autonomic, service-oriented healthcare application. To demonstrate the generalization of our TIP approach to be instantiated into the domain of up-to-date runtime testing for self-adaptive software systems, the TIP approach was applied to the self-adaptive JPacman 3.0 system. To measure the accuracy of the TIP engine, we consider and compare the work of a developer who manually identifyied changes that should be performed to update the test model after self-adaptation occurs in self-adaptive systems in our study. The experiments show how TIP is highly accurate for reductive change propagation across self-adaptive systems. Promising results have been achieved in simulating the additive changes as well.

Android application development has been of interest since the first Android smartphone was released. Applications are constantly getting more complex as well as smartphone hardware is getting better. New ways of developing Android applications are developed with time. There is Model View Presenter architecture that is the most used for android applications now and new View InteractorPresenter Entity Router architecture that is becoming more popular. But there is no empirical data to compare these architectures to understand what architecture will fit better for developing new applications. This thesis aims to compare the MVP and the VIPER android architectures using a few important metrics like maintainability, modifiability, testability, and performance. Results will answer what architecture is better for developing different types of projects. VIPERarchitecture showed better performance results and maintenance metrics comparison shows that both architectures have advantages and disadvantages.

In algorithmic computing, the program follows a predefined set of rules – the algorithm. The analyst/designer of the program analyzes the intended tasks of the program, defines the rules for its expected behaviour and programs the implementation. The creators of algorithmic software must therefore foresee, identify and implement all possible cases for its behaviour in the future application! However, what if the problem is not fully defined? Or the environment is uncertain? What if situations are too complex to be predicted? Or the environment is changing dynamically? In many such cases algorithmic computing fails. In such situations, the software needs an additional degree of freedom: Autonomy! Autonomy allows software to adapt to partially defined problems, to uncertain or dynamically changing environments and to situations that are too complex to be predicted. As more and more applications – such as autonomous cars and planes, adaptive power grid management, survivable networks, and many more – fall into this category, a gradual switch from algorithmic computing to autonomic computing takes place. Autonomic computing has become an important software engineering discipline with a rich literature, an active research community, and a growing number of applications.:Introduction 5 1 A Process Data Based Autonomic Optimization of Energy Efficiency in Manufacturing Processes, Daniel Höschele 9 2 Eine autonome Optimierung der Stabilität von Produktionsprozessen auf Basis von Prozessdaten, Richard Horn 25 3 Assuring Safety in Autonomous Systems, Christian Rose 41 4 MAPE-K in der Praxis - Grundlage für eine mögliche automatische Ressourcenzuweisung, in der Cloud Michael Schneider 59

This report presents the results of a thesis project that surveys and designs about the issue “Feature Model for Adaptive Computing”. In this project, there are two main issues, first one is about the Feature Modeling, and the second is how to use this Feature Modeling for adaptive computing.

In this thesis report, at the beginning, we present the problem we expected to solve and introduce some background information, including the knowledge of feature model and adaptive computing. Then we explain our solution and evaluate this solution. At the end of this report, we give a short conclusion about our thesis project and feature work.

This work is an investigation of how a software architecture can be changed in order to improve the support of the creation of a customised user interface. The parts of Symbian OS that are of interest for the work are described in detail. Then a comparison of the user interfaces of four different mobile devices is made, in order to get a picture of what the interfaces of such devices could look like. Also presented in the work is a modified reference architecture that supports customisation of all the features that have been identified in the comparison. Finally, the authors discuss how well the new architecture supports customisation of the user interface compared to the original Symbian OS architecture.