Esta tese tem o objetivo de definir um processo para análise de requisitos não-funcionais orientado a aspectos denominado PARNAFOA. Este processo utiliza, de maneira integrada, métodos de tratamento de requisitos não-funcionais, baseados no NFR Framework, e métodos orientados a aspectos. Como resultado principal obtém-se um modelo de casos de uso que incorpora novas funções relacionadas aos requisitos não-funcionais. A aplicação do PARNAFOA foi realizada em cinco sistemas de software, com domínios, características e complexidades diversos. A avaliação da aplicação deste processo mostrou que o tratamento dos requisitos não-funcionais, desde as fases iniciais do desenvolvimento dos sistemas de software, complementa o modelo de casos de uso com funções adicionais ou gera restrições de projeto. Se estes requisitos não forem considerados desde o início, a introdução posterior dessas funções pode causar alterações nos modelos consolidados ou as atividades de projeto podem ser realizadas sem considerar as restrições. As aplicações do PARNAFOA e sua conseqüente melhoria, incorporada após sua avaliação, permitiu torná-lo mais flexível do que sua versal inicial. Aplicações futuras, com outros tipos de requisitos não-funcionais, irão permitir o amadurecimento deste processo. / The aim of this thesis is to define an aspect-oriented non-functional requirements analysis process named PARNAFOA. This process applies nonfunctional requirements methods in an integrated manner, based on NFR Framework, and aspect-oriented methods. A use case model that embodies non-functional requirements as new functions is the main result obtained from this process. PARNAFOA application was performed in five software systems, with diverse features, domains and complexities. The evaluation of this process application showed that the treatment of these non-functional requirements, from the early phases of software systems development, complements the use case model with additional new functions or generates project restrictions. If these requirements are not considered from the very beginning, the introduction of these functions at a later phase can generate modifications in consolidated models or project activities, that do not consider these restrictions, can be performed. The PARNAFOA applications and consequent improvement, incorporated after the assessment, allowed it to become more flexible than the initial version. Future applications, with other non-functional requirements types, will provide this process maturity.

Uma das questões mais importantes nas linguagens e arcabouços orientados a aspectos atuais é a expressividade da linguagem ou mecanismo de definição de pointcuts. A expressividade de uma linguagem de pointcuts impacta diretamente a qualidade dos pointcuts, uma propriedade que pode ser decisiva para a eficácia das implementações de aspectos. Neste trabalho, propomos os seletores de pontos de junção como um mecanismo de extensão simples para enriquecer linguagens de pointcut atuais com elementos que fazem o papel de \"novos pointcuts primitivos\". Os seletores de pontos de junção permitem a criação de pointcuts com maior valor semântico. Apesar de existirem mecanismos similares em algumas abordagens existentes, o conceito subjacente não foi claramente definido ou completamente explorado. Apresentamos também uma arquitetura simples para a adição de seletores de pontos de junção a um arcabouço orientado a aspectos existente, e mostramos exemplos do uso de seletores para melhorar a qualidade de pointcuts e facilitar o desenvolvimento de aspectos. / One of the main issues in modern aspect-oriented programming languages and frameworks is the expressiveness of the pointcut language or mechanism. The expressiveness of pointcut languages directly impacts pointcut quality, a property that can be decisive for the effectiveness of aspect implementations. In this work we propose join point selectors as a simple extension mechanism for enriching current pointcut languages with constructs that play the role of \"new primitive pointcuts\". Join point selectors allow the creation of pointcuts with greater semantic value. Although similar mechanisms can be found in some existing approaches, the underlying concept has not yet been clearly defined nor fully explored. We also present a simple architecture for adding join point selectors to an existing aspect-oriented framework, and show examples of usage of join point selectors to enhance the quality of pointcuts and make aspect development easier.

Esta tese tem o objetivo de definir um processo para análise de requisitos não-funcionais orientado a aspectos denominado PARNAFOA. Este processo utiliza, de maneira integrada, métodos de tratamento de requisitos não-funcionais, baseados no NFR Framework, e métodos orientados a aspectos. Como resultado principal obtém-se um modelo de casos de uso que incorpora novas funções relacionadas aos requisitos não-funcionais. A aplicação do PARNAFOA foi realizada em cinco sistemas de software, com domínios, características e complexidades diversos. A avaliação da aplicação deste processo mostrou que o tratamento dos requisitos não-funcionais, desde as fases iniciais do desenvolvimento dos sistemas de software, complementa o modelo de casos de uso com funções adicionais ou gera restrições de projeto. Se estes requisitos não forem considerados desde o início, a introdução posterior dessas funções pode causar alterações nos modelos consolidados ou as atividades de projeto podem ser realizadas sem considerar as restrições. As aplicações do PARNAFOA e sua conseqüente melhoria, incorporada após sua avaliação, permitiu torná-lo mais flexível do que sua versal inicial. Aplicações futuras, com outros tipos de requisitos não-funcionais, irão permitir o amadurecimento deste processo. / The aim of this thesis is to define an aspect-oriented non-functional requirements analysis process named PARNAFOA. This process applies nonfunctional requirements methods in an integrated manner, based on NFR Framework, and aspect-oriented methods. A use case model that embodies non-functional requirements as new functions is the main result obtained from this process. PARNAFOA application was performed in five software systems, with diverse features, domains and complexities. The evaluation of this process application showed that the treatment of these non-functional requirements, from the early phases of software systems development, complements the use case model with additional new functions or generates project restrictions. If these requirements are not considered from the very beginning, the introduction of these functions at a later phase can generate modifications in consolidated models or project activities, that do not consider these restrictions, can be performed. The PARNAFOA applications and consequent improvement, incorporated after the assessment, allowed it to become more flexible than the initial version. Future applications, with other non-functional requirements types, will provide this process maturity.

A convergência da Internet com outras redes (telefonia móvel e televisão digital), o surgimento da computação ubíqua e crescente demanda pela computação autônoma, tem favorecido a existência de um ambiente constantemente modificado e altamente dinâmico, caracterizado pelo tratamento e transporte de conteúdo multimídia, heterogeneidade nos recursos, tecnologias de redes e dispositivos de acesso. Este cenário tem exigido a existência de sistemas adaptativos, ou seja, que tenham a capacidade de se adaptar dinamicamente em resposta a mudanças no contexto em que estão inseridos. O projeto de software de sistemas adaptativos que visem atender de forma satisfatória evolução e mudança neste novo ambiente heterogêneo da Internet tem particular relevância e complexidade. Um dos principais desafios é realizar a implementação de comportamentos adaptativos sem entrelaçamento com outras funcionalidades da aplicação, que podem levar a dificuldade de legibilidade e prejudicar a manutenção do código. Este trabalho procura abordar este tema empregando programação orientada a aspectos na especificação e implementação de uma camada de adaptação que atua sobre aplicações multimídia em rede utilizando abordagens de adaptação baseados em servidor. Em particular, através do uso da linguagem AspectJ, é mostrado como promovemos a separação do interesse de adaptabilidade de forma modular para permitir que a camada de adaptação realize configuração estática e dinâmica de processos de transmissão de fluxos multimídia a partir de mecanismos de monitoração do seu ambiente de operação. / The convergence of the Internet with other networks (e.g. Mobile Telecom and Digital Television Networks), the ubiquitous computing raising and the increasing demand on the autonomic computing has favored the existence of a constantly modified and highly dynamic environment. It is characterized by the treatment and transport of multimedia content and resources, network technologies and access devices heterogeneity. This scenario has demanded the existence of adaptive systems, which has the capacity to dynamically adapt based on the context where they are inserted. The software design for adaptive systems, which aim to deal on a satisfactory way the evolution and changes in this new heterogeneous Internet environment, has particular relevance and complexity. One of the main challenges is performing the development of adaptive behaviors without tangled and scattered code along other application functionalities, which could result in code legibly problems, affecting its maintenance. The main purpose of this work is the specification and development of an adaptation layer working in multimedia networked application and using server based adaptation approach, making use of aspect oriented programming. Specifically, through the adoption of the AspectJ language it was showed how the adaptability concern was well modularized by enabling the adaptation layer to perform static and dynamic configuration of the multimedia chains through the monitoring of its operational environment.

<p>The increasing complexity in the development of a configurable real-time system has emerged new principles of software techniques, such as aspect-oriented software development and component-based software development. These techniques allow encapsulation of the system's crosscutting concerns and increase the modularity of the software. The properties of a component that influences the systems performance or semantics are specified separately in entities called aspects, while basic functionality of the property still remains in the component. </p><p>When building a real-time system, different sets of configurations of aspects and components can be combined, resulting in different configurations of the system. The temporal behavior of the system changes and a way to ensure the predictability of the system is needed. </p><p>This thesis presents a tool for aspect-level worst-case execution time analysis, which gives a priori information about the temporal behavior of the system, before the process of composing aspects with components.</p>

<p>Rising complexity in the development of real-time systems has made it crucial to have reusable components and a more flexible way of configuring these components into a coherent system. Aspect-oriented system development (AOSD) is a technique that allows one to put a system’s crosscutting concerns into"modules"that are called aspects. Applying AOSD in real-time and embedded system development one can expect reductions in the complexity of the system design and development. </p><p>A problem with AOSD in its current form is that it does not support predictability in the time domain. Hence, in order to use AOSD in real-time system development, we need to provide ways of analyzing temporal behavior of aspects, components and resulting system (made from weaving aspects and components). Aspect analyzer is a tool that computes the worst-case execution time (WCET) for a set of components and aspects, thus, enabling support for predictability in the time domain of aspect-oriented real-time software. </p><p>A limitation of the aspect analyzer, until now, were that no verification had been made whether the aspect analyzer would produce WCET values that were close to the measured or computed (with another WCET analysis technique) WCET of an aspect-oriented real-time system. Therefore, in this thesis we perform a verification of the correctness of the aspect analyzer using a number of different methods for WCET analysis. These investigations of the correctness of the output from the aspect analyzer gave confidence to the automated WCET analysis. In addition, performing this verification led to the identification of the steps necessary to compute the WCETs of a piece of program, when using a third party tool, which gives the ability to write accurate input files for the aspect analyzer.</p>

<p>During the last years the need for real-time database services has increased due to the growing number of data-intensive applications needing to enforce real-time constraints. The COMponent-based Embedded real-Time database (COMET) is a real-time database developed to meet these demands. COMET is developed using the AspeCtual COmponent-based Real-time system Development (ACCORD) design method, and consists of a number of components and aspects, which can be composed into a number of different configurations depending on system demands, e.g., Quality of Service (QoS) management can be used in unpredictable environments. </p><p>In embedded systems with requirementson high up-time it may not be possible to temporarily shut down the system for reconfiguration. Instead it is desirable to enable dynamic reconfiguration of the system, exchanging components during run-time. This in turn sets demands on the feedback control of the system to adjust to these new conditions, since a new time variant system has been created. </p><p>This thesis project implements improvements in COMET to create a more stable database suitable for further development. A mechanism for dynamic reconfiguration of COMET is implemented, thus, enabling components and aspects to be swapped during run-time. Adaptive feedback control algorithms are also implemented in order to better adjust to workload variations and database reconfiguration.</p>

<p>Increasing complexity of real-time systems and demands for enabling their configurability and tailorability are strong motivations for applying new software engineering principles such as aspect-oriented and component-based software development. The integration of these two techniques into real-time systems development would enable: (i) efficient system configuration from the components in the component library based on the system requirements, (ii) easy tailoring of components and/or a system for a specific application by changing the behavior (code) of the component by aspect weaving, and (iii) enhanced flexibility of the real-time and embedded software through the notion of system configurability and component tailorability.</p><p>In this thesis we focus on applying aspect-oriented and component-based software development to real-time system development. We propose a novel concept of aspectual component-based real-time system development (ACCORD). ACCORD introduces the following into real-time system development: (i) a design method that assumes the decomposition of the real-time system into a set of components and a set of aspects, (ii) a real-time component model denoted RTCOM that supports aspect weaving while enforcing information hiding, (iii) a method and a tool for performing worst-case execution time analysis of different configurations of aspects and components, and (iv) a new approach to modelling of real-time policies as aspects.</p><p>We present a case study of the development of a configurable real-time database system, called COMET, using ACCORD principles. In the COMET example we show that applying ACCORD does have an impact on the real-time system development in providing efficient configuration of the real-time system. Thus, it could be a way for improved reusability and flexibility of real-time software, and modularization of crosscutting concerns.</p><p>In connection with development of ACCORD, we identify criteria that a design method for component-based real-time systems needs to address. The criteria include a well-defined component model for real-time systems, aspect separation, support for system configuration, and analysis of the composed real-time system. Using the identified set of criteria we provide an evaluation of ACCORD. In comparison with other approaches, ACCORD provides a distinct classification of crosscutting concerns in the real-time domain into different types of aspects, and provides a real-time component model that supports weaving of aspects into the code of a component, as well as a tool for temporal analysis of the weaved system.</p> / Report code: LiU-TEK-LIC-2003:23.

Our main focus in this thesis is on providing guidelines, methods, and tools for design, configuration, and analysis of configurable and reusable real-time software, developed using a combination of aspect-oriented and component-based software development. Specifically, we define a reconfigurable real-time component model (RTCOM) that describes how a real-time component, supporting aspects and enforcing information hiding, could efficiently be designed and implemented. In this context, we outline design guidelines for development of real-time systems using components and aspects, thereby facilitating static configuration of the system, which is preferred for hard real-time systems. For soft real-time systems with high availability requirements we provide a method for dynamic system reconfiguration that is especially suited for resourceconstrained real-time systems and it ensures that components and aspects can be added, removed, or exchanged in a system at run-time. Satisfaction of real-time constraints is essential in the real-time domain and, for real-time systems built of aspects and components, analysis is ensured by: (i) a method for aspectlevel worst-case execution time analysis; (ii) a method for formal verification of temporal properties of reconfigurable real-time components; and (iii) a method for maintaining quality of service, i.e., the specified level of performance, during normal system operation and after dynamic reconfiguration. We have implemented a tool set with which the designer can efficiently configure a real-time system to meet functional requirements and analyze it to ensure that non-functional requirements in terms of temporal constraints and available memory are satisfied. In this thesis we present a proof-of-concept implementation of a configurable embedded real-time database, called COMET. The implementation illustrates how our methods and tools can be applied, and demonstrates that the proposed solutions have a positive impact in facilitating efficient development of families of realtime systems.

We discuss the design and analysis of a code generator for C++, implemented in the Umple model-oriented programming technology. Umple adds UML constructs and patterns to various base programming languages such as Java and PhP. Umple code generators create code for those constructs, which can include UML associations and state machines, as well as patterns such as immutable and singleton. Base language methods are passed through unchanged along with the generated code. Creating a C++ code generator for Umple posed many challenges, all of which are discussed in this thesis: We had to focus on the appropriate C++ idioms and stylistic conventions to follow. We followed a test-driven development process to ensure that the resulting code was correct. To evaluate the work, we compared our C++ generator with those in other tools such as ArgoUML and IBM Rational Software Architect. We conclude that our C++ generator is superior in many ways to these widely used tools because it is more complete and generates better quality code.