A Framework for Requirements Decomposition, SLA Management and Dynamic System Reconfiguration

To meet user requirements, systems can be built from Commercial-Off-The-Shelf (COTS) components, potentially from different vendors. However, the gap between the requirements referring to the overall system and the components to build the system from can be large. To close the gap, it is required to decompose the requirements to a level where they can be mapped to components. When the designed system is deployed and ready for operations, its services are sold and pro-vided to customers. One important goal for service providers is to optimize system resource utilization while ensuring the quality of service expressed in the Service Level Agreements (SLAs). For this purpose, the system can be reconfigured dynamically according to the cur-rent workload to satisfy the SLAs while using only necessary resources. To manage the re-configuration of the system at runtime, a set of previously defined patterns called elasticity rules can be used. In elasticity rules, the actions that need to be taken to reconfigure the sys-tem are specified. An elasticity rule is generally invoked by a trigger, which is generated in reaction to a monitoring event. In this thesis, we propose a model-driven management framework which aims at user re-quirements satisfaction, SLA compliance management and enabling dynamic reconfiguration by reusing the design information at runtime. An approach has been developed to derive automatically a valid configuration starting from low level requirements called service configurations. However, the service configurations are far from requirements a user would express. To generate a system configuration from user requirements and alleviate the work of designer, we generate service configurations by de-composing functional user requirements to the level where components can be selected and put together to satisfy the user requirements. We integrated our service configurations gen-erator with the previous configuration generator. In our framework, we reuse the information acquired from system configuration and dimen-sioning to generate elasticity rules offline. We propose a model driven approach to check the compliance of SLAs and generate triggers for invoking applicable elasticity rules when system reconfiguration is required. For handling multiple triggers generated at the same time, we propose a solution to automatically correlate the actions of invoked elasticity rules, when re-quired. The framework consists of a number of metamodels and a set of model transfor-mations. We use the Unified Modeling Language (UML) and its profiling mechanism to de-scribe all the artifacts in the proposed framework. We implement the profiles using Eclipse Modeling Framework (EMF) and Papyrus. To implement the processes, we use the Atlas Transformation Language (ATL). We also use the APIs of the Object Constraint Language (OCL) in the Eclipse environment to develop a tool for checking constraints and generating triggers

Pattern-Based Generation of AMF Configurations

Information Technology service providers aim at attracting customers by providing services that meet a high level of quality. They should not only satisfy functional requirements, but also non-functional requirements. An important non-functional requirement is the level of service availability. Service Availability Forum (SAForum), a consortium of communications and computing companies, has developed a set of services and standard Application Programming Interfaces (APIs) to address the issue of high availability for the Commercial-off-the-shelf (COTS)-based systems and enable portability. Among the services standardized by the SAForum, the Availability Management Framework (AMF) has the important role of ensuring the high availability of an application and its services, by managing the redundant application components deployed on the cluster. To achieve this task, AMF requires a configuration that represents the logical organization of the application components and their services. The design of AMF configurations is a complex and error prone task. Automation of the process is the first step towards improving the quality of such configurations. It also enables exploring different potential solutions for a given set of requirements. An automated approach to generate configurations for applications to deploy on top of the SAForum middleware has been proposed in the context of the MAGIC project. This approach, however, may generate several configurations among which some may not meet the required level of service availability. Therefore, the system designer needs to evaluate the generated configurations using an availability analysis tool to select an appropriate one for deployment. One may want to improve this process by targeting directly in the generation process, the configurations that can guarantee the requested level of service availability. The objective of this thesis is to propose solutions to enhance this configuration generation process and generate configurations that can guarantee the required level of service availability without using advanced analysis tools. For this purpose, we propose configuration design patterns to improve the expected level of service availability and quantitative methods that eliminate some configurations that do not meet the availability requirement. The configuration design patterns improve the expected level of service availability by selecting the best configuration options. The methods estimate service availability for the different possible combinations of software components, which can provide the requested services, taking into account the properties of these components and the behavior of the SAForum middleware. As a proof of concept, we have embedded our proposed solutions into a prototype tool as an eclipse plug-in and validated our work with case studies

Uma proposta para rastreabilidade no desenvolvimento de software

Orientador: Mario JinoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Rastreabilidade tem sido um tópico de pesquisa no desenvolvimento de software por pelo menos 40 anos, sendo adicionada a muitos padrões, como o DOD-STD-2167A e o IEEE 830-1998. Este último, por exemplo, afirma que uma boa especificação de requisitos de software deve ser rastreável. A rastreabilidade fornece muitos benefícios para projetos de software, tais como: identificação das razões para decisões de design, prevenção de problemas de dependência, identificação de responsabilidades em um projeto, estimação de impacto e de custo de modificações, e medição do progresso de desenvolvimento. Sucintamente, a rastreabilidade permite a geração de um produto de melhor qualidade. Dois principais focos surgiram na literatura nos últimos anos: desenvolvimento baseado em modelo e geração automática de rastros. O primeiro trata da modelagem de rastreabilidade, definindo relações e elementos de um projeto; o segundo trata da descoberta automática de relações entre elementos. Vários conceitos foram definidos até agora, como rastreabilidade bidirecional, rastreabilidade de especificações pré e pós-requisitos, rastreabilidade horizontal e vertical, e rastreabilidade explícita e implícita. Embora haja um consenso geral sobre a maioria dos conceitos relacionados a rastreabilidade, há uma falta de consenso sobre como, e o quê, deve ser rastreado; não há consenso sobre: quais relações são relevantes para os projetos de desenvolvimento de software, quais elementos devem ser rastreados, como as mudanças nos elementos de um projeto afetam as relações existentes, ou como atualizar as relações dadas certas mudanças. Os modelos de rastreabilidade visam responder a essas questões fornecendo um padrão para ser usado como uma guia em projetos de desenvolvimento de software; entretanto, não há consenso sobre o que um modelo deve conter. Existe uma variedade de modelos, cada um considerando diferentes tipos de relações, elementos, e possuindo diferentes focos. Além disso, a maioria dos modelos possui problemas que tornam o seu uso difícil, ou até mesmo impossível; por exemplo, existem modelos que não descrevem - suficientemente ou em nada - as ligações de rastreabilidade que propõem. Este trabalho visa a ajudar nesta questão, fornecendo uma contribuição dupla: um modelo de referência para criar e avaliar modelos de rastreabilidade, e um metamodelo abrangente, construído em cima do modelo de referência, para adicionar rastreabilidade a projetos de desenvolvimento de software. Nosso Modelo de Referência para rastreabilidade define os elementos básicos em um modelo de rastreabilidade e define conjuntos básicos de: ações, tipos de ligações, tipos de artefatos, e processos. Propriedades necessárias para o conjunto de tipos de ligações e o conjunto de tipos de artefatos também são fornecidas. Nosso Metamodelo para rastreabilidade é composto por: um modelo conceitual descrevendo e organizando os elementos de rastreabilidade; um conjunto de tipos de artefatos representando as atividades definidas no Modelo de Referência, além de um conjunto de tipos de artefatos criados para registrar decisões de design; um conjunto de tipos de ligações que modelam diferentes relações de rastreabilidade; e um conjunto de processos para garantir a consistência de projetosAbstract: Traceability has been a topic of research in software development for at least 40 years, being added to many standards, such as the DOD-STD-2167A and the IEEE 830-1998. The latter, for instance, states that a good software requirements specification should be traceable. Traceability provides many benefits to software projects, such as: identification of the reasons for design decisions, avoidance of dependency issues, identification of accountability in a project, estimation of impact and cost of modifications, and measurement of development progress. Succintly, traceability allows the generation of a better quality product. Two main focuses have emerged in the literature in recent years: model-based development and automated trace generation. The former concerns modeling traceability by defining relations and elements in a project; the latter concerns automatic discovery of relations between elements in a project. Several concepts have been defined so far, such as bidirectional traceability, pre and post-requirements specification traceability, horizontal and vertical traceability, and explicit and implicit traceability. While there is general consensus on most concepts related to traceability, there is a lack of consensus on how, and what, should be traced; there is no consensus on which relations are relevant for software development projects, which elements should be traced, how changes in elements of a project affects existing relations, or how to update relations given certain changes. Traceability models aim to answer these questions by providing a standard to be used as a guide in software development projects; however, there is no consensus on what a model should contain. There is a variety of models, each considering different types of relations, elements, and having distinct focuses. Also, the majority of models have issues which makes them difficult or even impossible to use; for instance, there are models which do not describe - sufficiently or at all - traceability links which they propose. This work aims to help in this issue by providing a twofold contribution: a reference model for creating and evaluating traceability models, and a comprehensive metamodel, built on top of the reference model, to add traceability to software development projects. Our Reference Model for traceability defines the basic elements in a traceability model and defines basic sets of: actions, link types, artifact types, and processes. Necessary properties for the sets of link types and artifact types are also provided. Our Metamodel for traceability is composed of: a conceptual model describing and organizing the elements of traceability; a set of artifact types representing the activities of the Reference Model, plus a set of artifact types created to record design decisions; a set of link types modeling different traceability relations; and a set of processes to ensure project consistencyDoutoradoEngenharia de ComputaçãoDoutor em Engenharia Elétrica1142618CAPE