Automating Mappings between Use Case Diagrams and Feature Models for Software Product Lines

Features have been widely used by the product line community to model variability. They represent the common and variable characteristics of the members of a product line. They are very well suited for the configuration of product line members. Outside the product line community, use cases are also widely used to model the functionality of systems at a similar level of abstraction but from a user perspective. Significant work has been done by several authors regarding the possible relationship between these two perspectives of a system. Nonetheless, this has been done in an informal way. In this paper we explore the relationships between these two perspectives and describe a possible approach to automate the transformation from UML use case to feature models

Refinement and variability techniques in model transformation of software requirements

Tese de Doutoramento em Tecnologias e Sistemas de InformaçãoThis thesis begins with analyzing user functional requirements (as use cases) from the perspective of detail. In that sense, it investigates the applicability of the UML (Unified Modeling Language) «include» relationship to the representation of use case refinement and proposes another relationship for that purpose. It also clarifies the process of modeling use cases with UML when refinement is involved and provides for some guidelines in order to conduct that process. Afterwards, the work of this thesis on use case modeling is expanded to the field of SPLs (Software Product Lines) by means of exploring the UML «extend» relationship. It talks about alternative, specialization and option use cases as the representation of the three variability types this thesis proposes to be translated into stereotypes to mark use cases. Then, this thesis incorporates the refinement of logical architectures with variability support from use cases also with variability support in the 4SRS (Four Step Rule Set) transition method for model transformation of analysis artifacts (use cases) into design artifacts (logical architectures represented as UML component diagrams). The model transformation the 4SRS guides in a stepwise way, from use cases into logical architectures, is based on a software development pattern that addresses architecture. This thesis yields a multilevel and multistage pattern classification that grounds the use of that pattern to generate system functional requirements (as logical architectures). Lastly, the 4SRS transition method is modeled with the SPEM (Software & Systems Process Engineering Metamodel) and formalized as a small software development process dedicated at transitioning from the analysis to the design of software. After that, this thesis presents a case study on the automation of the 4SRS and thoroughly elaborates on the transformation rules that support the model transformations of the 4SRS.Esta tese começa por analisar requisitos funcionais de utilizador (enquanto casos de utilização) sob a perspectiva do detalhe. Nesse sentido, esta tese investiga a aplicabilidade da relação UML (Unified Modeling Language) «include» para a representação do refinamento de casos de utilização e propõe outra relação para esse fim. Esta tese também clarifica o processo de modelação de casos de utilização com a UML quando esse processo envolve refinamento e fornece algumas diretrizes para a condução desse processo. De seguida, o trabalho desta tese em modelação de casos de utilização é expandido para o campo das linhas de produtos de software através da exploração da relação UML «extend». Esse trabalho fala de casos de utilização alternativos, de especialização e opcionais como a representação dos três tipos de variabilidade que esta tese propõe que sejam traduzidos em estereótipos para a marcação de casos de utilização. Depois, esta tese incorpora o refinamento de arquitecturas lógicas com suporte à variabilidade a partir de casos de utilização também com suporte à variabilidade no método de transição 4SRS (Four Step Rule Set) para a tranformação de modelos de artefatos de análise (casos de utilização) em modelos de artefatos de design (arquitecturas lógicas representadas como diagramas de components UML). A transformação de modelos que o 4SRS guia por passos, de casos de utilização em arquitecturas lógicas, baseia-se num padrão de desenvolvimento de software que visa arquitetura. Esta tese produz uma classificação multinível e multietapa de padrões, que sustenta a utilização desse padrão na geração de requisitos funcionais de sistema (enquanto arquitecturas lógicas). Por fim, o método de transição 4SRS é modelado com o SPEM (Software & Systems Process Engineering Metamodel) e formalizado como um pequeno processo de desenvolvimento de software dedicado a transitar da análise para o design the software. Depois disso, esta tese apresenta um estudo de caso sobre a automatização do 4SRS e elabora minuciosamente acerca das regras de transformação que apoiam as transformações de modelos do 4SRS

Deriving software design models from a set of business processes

Requirements elicitation is a crucial activity and one of the first steps in software development process. A popular way to capture and describe requirements is through UML use case models. Transforming require- ment specifications into software design models is a complex and error prone software development activity. Software design usually involves several models, each one representing a different perspective. One of those perspectives is the data perspective which can be modeled using a data model. Although of the importance of this model, few works has been done to derive a data model from use case model. The 4SRS (4-Step Rule Set) method generates a logical architecture of a software-based system, based on a use case model. This paper proposes an approach to adapt and extend the 4SRS method in order to generate a data model supporting the generated logical architecture and the elicited requirements based in a set of business process models.This work has been supported by FCT - Fudação para a Ciência e Tecnologia in the scope of the project: PEst-UID/CEC/00319/201

Foundations of systems and properties:methodological support for modeling properties of software-intensive systems

Engineering of software-intensive systems is concerned with the creation and evolution of systems that shall exhibit desired properties in their execution as well as development environment. In this context, the motivation of this thesis, derived from current development practice, was twofold. Firstly, software development methods are increasingly required to extend their scope of applicability towards systems engineering. As a consequence, their modeling approaches must be able to cope with a larger diversity of systems and consequently a larger diversity of properties. But these approaches still need to provide a smooth transition to software modeling. Secondly, non-functional properties, which are largely a result of this implicit systems scope, play a major role in the way we design our software-intensive systems. The conceptual aids of current development methods, however, are still less mature in their explicit support for non-functional properties compared with their ability to support functional ones. The principal objective of this thesis is to contribute toward an improved model-based treatment of non-functional properties in development methods. Because we cannot discuss properties independently of the objects they are ascribed to, this objective amounts to a progression from modeling of software and its properties to modeling of interrelated systems and their properties. To address this aim a philosophy of properties and systems is proposed. The philosophy is expressed as a holistic conceptual model of properties and/of systems. It is complemented with some basic rules, which we call tenets. Tenets formulate how we use the philosophical knowledge. The conceptual model offers the foundations for a more generalized understanding of those fundamentally different types of systems and different types of properties that are relevant in software-intensive systems engineering. The generality of our holistic model draws the benefits from our investigations in the areas of systems science, cognitive science, and basic philosophy. The model helps to scrutinize and make sense of the large amount of data in the literature about "non-functional" issues in software engineering. The model is applicable in the derivation of methodological building blocks that can be incorporated into development methods. The building blocks include (a) a general model to discover stakeholders and properties for a given system, (b) a principled manner to trace the fundamentally different types of properties through hierarchies of systems, and (c) a proposal for the representation of systems, their properties and property traces in the UML. The concrete application of the gained knowledge to software engineering results in a proposal for a context-sensitive, customizable quality attribute model. It also results in a proposal on how to structure quality descriptions of software components. In order for such descriptions to be standardized and possibly tool-automated, this thesis proposes to utilize the Reusable Asset Specification and suggests alternatives for its XML-based representation

MINERVA : Model drIveN and sErvice oRiented framework for the continuous improVement of business process & relAted tools

Organizations are facing several challenges nowadays, one of the most important ones being their ability to react quickly to changes either to their business process (BP) models or to the software implementing them. These changes can come from different sources: external requirements from partners or the market, or new internal requirements for the way that things are carried out by the defined BPs; they may also arise from improvement opportunities detected for the BPs defined, based on BPs execution monitoring and execution evaluation that is done by the organization, and/or its partners and customers. The increasing complexity of both BPs models and the software implementing them, requires the changes needed or the improvements to be carefully weighed against the impact their introduction will have; they ought also to be carried out in a systematic way to assure a successful development. Two key elements are to provide these requirements: the separation of BPs definition from their implementation to minimize the impact of changes in one to the other, and a process to introduce the changes or improvements in the existing BPs and/or software implementing them. Business Process Management (BPM) provides the means for guiding and supporting the modeling, implementation, deployment, execution and evaluation of BPs in an organization, based on the BP lifecycle. The realization of BPs by means of services provides the basis for separating their definition from the technologies implementing them and helps provide a better response to changes in either of the layers defined -definition and implementation of business processes- with minimum impact on the other. Modeling of both BP and services is a key aspect to support this vision, helping provide traceability between elements from one area to the other, so easing the analysis of the impact of changes, among other things. Models have proven to play an important role in the software development process, one of its key uses in the context of BP realization by means of services is that of designing services at a more abstract level than with specific technologies, also promoting reuse by separating services logic from its implementation. MINERVA: Model drIveN & sErvice oRiented framework for the continuous business process improVement & relAted tools is the framework that has been defined in this thesis work; it takes into account all the aspects mentioned, in which the SOC and MDD paradigms are applied to BPs focusing on their continuous improvement, extending an existing BP lifecycle with explicit execution measurement and improvement activities and elements. It is made up of three dimensions: i) conceptual, which defines the concepts that are managed throughout the framework. ii) methodological, which defines a methodology for service oriented development from BPs with automatic generation of SoaML service models from BPMN2 models, along with a continuous improvement process based on execution measurement of the occurrences of BPs in the organization to carry out the improvement effort. iii) tools support for the whole proposal based on several existing tools we have integrated, along with new ones we have developed. The proposals in MINERVA have been validated by means of an experiment and two case studies carried out in the context of real projects in two organizations, from which, as the main result of the applications performed, it can be concluded that MINERVA can be a useful and key guide for the continuous improvement of BPs realized by services and for the development of service oriented systems from BPs, with automatic generation of service models from BP models.Las organizaciones se enfrentan en la actualidad a varios retos, siendo uno de los más importantes su capacidad para reaccionar rápidamente a los cambios ya sea en sus modelos de procesos de negocio (PN) o en el software que los implementa. Estos cambios pueden provenir de distintas fuentes: requisitos externos de socios o del mercado, o nuevos requisitos internos para la forma en que las cosas se llevan a cabo por los PNs definidos; también pueden surgir de las oportunidades de mejora detectadas para los PNs definidos, en base al monitoreo y evaluación de la ejecución de los PNs llevada a cabo por la organización, y/o sus socios y clientes. La creciente complejidad de los modelos de PNs y del software que los implementa, requiere que los cambios o las mejoras sean sopesados cuidadosamente contra el impacto que su introducción tendrá; también deben llevarse a cabo de manera sistemática para asegurar un desarrollo exitoso. Dos elementos son clave para proveer estos requisitos: la separación de la definición de los PNs de su implementación, para minimizar el impacto de los cambios de uno en otro, y un proceso para introducir los cambios o mejoras en los PNs y/o en el software que los implementa. La Gestión de Procesos de Negocio (Business Process Management, BPM) proporciona los medios para guiar y apoyar el modelado, implementación, despliegue, ejecución y evaluación de PNs en una organización, basado en el ciclo de vida de PNs. La realización de PNs con servicios proporciona la base para la separación de su definición de las tecnologías para implementarlos, y ayuda a proporcionar una mejor respuesta a los cambios en cualquiera de las capas definidas -definición e implementación de procesos de negocio- con un impacto mínimo sobre la otra. El modelado de PNs y servicios es un aspecto clave para apoyar esta visión, ayudando a proveer trazabilidad entre los elementos de un área a la otra, por lo tanto facilitando el análisis del impacto de los cambios, entre otras cosas. Los modelos han demostrado jugar un papel importante en el proceso de desarrollo de software, uno de sus usos principales en el contexto de la realización de PNs con servicios es el de diseñar servicios a un nivel más abstracto que con tecnologías específicas, promoviendo la reutilización separando la lógica de los servicios de su implementacion. MINERVA: Model drIveN & sErvice oRiented framework for the continuous business process improVement & relAted tools es el marco que se ha definido en este trabajo de tesis, que toma en cuenta todos los aspectos mencionados, en el cual los paradigmas de Computación Orientada a Servicios (Service Oriented Computing, SOC) y Desarrollo Dirigido por Modelos (Model Driven Development, MDD) se aplican a los PNs con foco en su mejora continua, extendiendo un ciclo de vida PN existente con actividades y elementos explícitos para la medición de la ejecución y mejora de PNs. El marco se compone de tres dimensiones: i) conceptual, que define los conceptos que se manejan en todo el marco. ii) metodológica, que define una metodología para el desarrollo orientado a servicios desde PNs, con generación automática de modelos de servicio en SoaML desde modelos en BPMN2, junto con un proceso de mejora continua basado en la medición de la ejecución de las ocurrencias de los PNs en la organización para llevar a cabo el esfuerzo de mejora. iii) soporte de herramientas para la propuesta completa basado en la integracion de varias herramientas existentes, junto con otras nuevas que hemos desarrollado. Las propuestas de MINERVA han sido validadas por medio de un experimento y dos casos de estudio realizados en el marco de proyectos reales en dos organizaciones, de los cuales, como resultado principal de las aplicaciones realizadas, se puede concluir que MINERVA puede ser una guía útil y clave para la mejora continua de PNs realizados por servicios y para el desarrollo de sistemas orientados a servicios desde PNs, con generación automática de modelos de servicio a partir de modelos de PN

Adaptation-Aware Architecture Modeling and Analysis of Energy Efficiency for Software Systems

This thesis presents an approach for the design time analysis of energy efficiency for static and self-adaptive software systems. The quality characteristics of a software system, such as performance and operating costs, strongly depend upon its architecture. Software architecture is a high-level view on software artifacts that reflects essential quality characteristics of a system under design. Design decisions made on an architectural level have a decisive impact on the quality of a system. Revising architectural design decisions late into development requires significant effort. Architectural analyses allow software architects to reason about the impact of design decisions on quality, based on an architectural description of the system. An essential quality goal is the reduction of cost while maintaining other quality goals. Power consumption accounts for a significant part of the Total Cost of Ownership (TCO) of data centers. In 2010, data centers contributed 1.3% of the world-wide power consumption. However, reasoning on the energy efficiency of software systems is excluded from the systematic analysis of software architectures at design time. Energy efficiency can only be evaluated once the system is deployed and operational. One approach to reduce power consumption or cost is the introduction of self-adaptivity to a software system. Self-adaptive software systems execute adaptations to provision costly resources dependent on user load. The execution of reconfigurations can increase energy efficiency and reduce cost. If performed improperly, however, the additional resources required to execute a reconfiguration may exceed their positive effect. Existing architecture-level energy analysis approaches offer limited accuracy or only consider a limited set of system features, e.g., the used communication style. Predictive approaches from the embedded systems and Cloud Computing domain operate on an abstraction that is not suited for architectural analysis. The execution of adaptations can consume additional resources. The additional consumption can reduce performance and energy efficiency. Design time quality analyses for self-adaptive software systems ignore this transient effect of adaptations. This thesis makes the following contributions to enable the systematic consideration of energy efficiency in the architectural design of self-adaptive software systems: First, it presents a modeling language that captures power consumption characteristics on an architectural abstraction level. Second, it introduces an energy efficiency analysis approach that uses instances of our power consumption modeling language in combination with existing performance analyses for architecture models. The developed analysis supports reasoning on energy efficiency for static and self-adaptive software systems. Third, to ease the specification of power consumption characteristics, we provide a method for extracting power models for server environments. The method encompasses an automated profiling of servers based on a set of restrictions defined by the user. A model training framework extracts a set of power models specified in our modeling language from the resulting profile. The method ranks the trained power models based on their predicted accuracy. Lastly, this thesis introduces a systematic modeling and analysis approach for considering transient effects in design time quality analyses. The approach explicitly models inter-dependencies between reconfigurations, performance and power consumption. We provide a formalization of the execution semantics of the model. Additionally, we discuss how our approach can be integrated with existing quality analyses of self-adaptive software systems. We validated the accuracy, applicability, and appropriateness of our approach in a variety of case studies. The first two case studies investigated the accuracy and appropriateness of our modeling and analysis approach. The first study evaluated the impact of design decisions on the energy efficiency of a media hosting application. The energy consumption predictions achieved an absolute error lower than 5.5% across different user loads. Our approach predicted the relative impact of the design decision on energy efficiency with an error of less than 18.94%. The second case study used two variants of the Spring-based community case study system PetClinic. The case study complements the accuracy and appropriateness evaluation of our modeling and analysis approach. We were able to predict the energy consumption of both variants with an absolute error of no more than 2.38%. In contrast to the first case study, we derived all models automatically, using our power model extraction framework, as well as an extraction framework for performance models. The third case study applied our model-based prediction to evaluate the effect of different self-adaptation algorithms on energy efficiency. It involved scientific workloads executed in a virtualized environment. Our approach predicted the energy consumption with an error below 7.1%, even though we used coarse grained measurement data of low accuracy to train the input models. The fourth case study evaluated the appropriateness and accuracy of the automated model extraction method using a set of Big Data and enterprise workloads. Our method produced power models with prediction errors below 5.9%. A secondary study evaluated the accuracy of extracted power models for different Virtual Machine (VM) migration scenarios. The results of the fifth case study showed that our approach for modeling transient effects improved the prediction accuracy for a horizontally scaling application. Leveraging the improved accuracy, we were able to identify design deficiencies of the application that otherwise would have remained unnoticed