Architectural level risk assessment

Many companies develop and maintain large-scale software systems for public and financial institutions. Should a failure occur in one of these systems, the impact would be enormous. It is therefore essential, in maintaining a system\u27s quality, to identify any defects early on in the development process in order to prevent the occurrence of failures. However, testing all modules of these systems to identify defects can be very expensive. There is therefore a need for methodologies and tools that support software engineers in identifying the defected and complex software components early on in the development process.;Risk assessment is an essential process for ensuring high quality software products. By performing risk assessment during the early software development phases we can identify complex modules, thus enables us to enhance resource allocation decisions.;To assess the risk of software systems early on in the software\u27s life cycle, we propose an architectural level risk assessment methodology. It uses UML specifications of software systems which are available early on in the software life cycle. It combines the probability of software failures and the severity associated with these failures to estimate software risk factors of software architectural elements (components/connectors), the scenarios, the use cases and systems. As a result, remedial actions to control and improve the quality of the software product can be taken.;We build a risk assessment model which will enable us to identify complex and noncomplex software components. We will be able to estimate programming and service effort, and estimate testing effort. This model will enable us also to identify components with high risk factor which would require the development of effective fault tolerant mechanisms.;To estimate the probability of software failure we introduced and developed a set of dynamic metrics which are used to measure dynamic of software architectural elements from UML static models.;To estimate severity of software failure we propose UML based severity methodology. Also we propose a validation process for both risk and severity methodologies. Finally we propose prototype tool support for the automation of the risk assessment methodology

A Methodology to Support the Maintenance of Object -Oriented Systems Using Impact Analysis.

Object-Oriented (OO) systems are difficult to understand due to the complex nature of the relationships that object-orientation supports. Inheritance, polymorphism, encapsulation, information hiding, aggregation, and association combine to make maintenance of OO systems difficult. Due to the presence of these characteristics in OO systems, maintenance activities on OO systems often have unexpected or unseen effects on the system. These effects can ripple through system components, complicating maintenance and testing of the system. The ability to trace the effects of maintenance provides the maintainer with knowledge that assists in debugging and testing modified and affected components. In this research, we show that the architecture of an OO system provides an effective framework for determining the impact of system changes. We developed the Comparative Software Maintenance (CSM) methodology to support the maintenance of OO systems. Through this methodology, we model relationships and structures, analyze the models to determine components that change as a result of maintenance, and perform impact analysis to determine components that are candidates for re-testing as a result of maintenance activity. The methodology includes a new data model, called Extended Low-Level Software Architecture (ELLSA), that facilitates impact analysis. CSM locates potential side effects, ripple effects, and other effects of maintenance on class structures, methods, and objects. The comprehensive architecture model enables CSM to perform either predictive, pre-modification impact analysis or post-modification impact analysis. The improved impact analysis process found in the methodology determines impact of changes to the component level. We apply the results of impact analysis to determine component level testing requirements. CSM enhances program understanding through the use of ELLSA. It also provides assistance for capturing complex dependencies found in object-oriented code. The methodology is implemented in JFlex. The automation provided by JFlex makes the application of CSM feasible

Métricas 00 aplicadas a código objeto java

Orientador : Márcio Eduardo DelamaroDissertaçao (mestrado) - Universidade Federal do ParanáResumo: Na busca de melhorias no processo de desenvolvimento de software para a obtenção de um produto de qualidade, várias métricas têm sido propostas, com as quais pode-se gerenciar este processo e detectar falhas de projeto. As métricas de software auxiliam na coleta de informação, fornecendo dados qualitativos e quantitativos sobre o processo e o produto de software. Elas identificam onde os recursos são necessários, constituindo assim importante fonte de informação para a. tomada, de decisão. Métricas podem ser aplicadas em diversas fases do desenvolvimento e em diversos produtos intermediários como especificação de requisitos, projeto ou código fonte. Este trabalho mostra a falibilidade de coletar-se algumas métricas de software a partir do código objeto (bytecode) .Java. Tal abordagem pode ser útil em atividades como: teste de programas que utilizam componentes de terceiros, re-engeiiharia e outras nas quais não se tenha acesso ao código fonte. As métricas coletadas a partir do bytecode Java foram aplicadas em um estudo de caso com dois sistemas onde procurou-se relacionar as métricas com a propensão a falhas.Abstract: Searching for improvements in the software development process and aiming at a product with high quality, several metrics, that help to manage the software process and to detect project flaws, have been proposed. Software metrics provide qualitative and quantitative about the software process and the software product. The identify where resources should be allocated, being an important source for decision making. They can be applied in any phase of the development and on different intermediary products as requirement specification, design or source code. This work shows the feasibility of collecting some software metrics directly from Java object programs (Java bytecode). Such an approach can be useful in activities like: testing of third party components, reengineering and others activities where the source code is not available. This approach has been applied in a case study to two Java systems, trying to relate the metrics to the existence of faults

Model driven language engineering

Modeling is a most important exercise in software engineering and development and one of the current practices is object-oriented (OO) modeling. The Object Management Group (OMG) has defined a standard object-oriented modeling language the Unified Modeling Language (UML). The OMG is not only interested in modeling languages; its primary aim is to enable easy integration of software systems and components using vendor-neutral technologies. This thesis investigates the possibilities for designing and implementing modeling frameworks and transformation languages that operate on models and to explore the validation of source and target models. Specifically, we will focus on OO models used in OMG's Model Driven Architecture (MDA), which can be expressed in terms of UML terms (e.g. classes and associations). The thesis presents the Kent Modeling Framework (KMF), a modeling framework that we developed, and describes how this framework can be used to generate a modeling tool from a model. It then proceeds to describe the customization of the generated code, in particular the definition of methods that allows a rapid and repeatable instantiation of a model. Model validation should include not only checking the well-formedness using OCL constraints, but also the evaluation of model quality. Software metrics are useful means for evaluating the quality of both software development processes and software products. As models are used to drive the entire software development process it is unlikely that high quality software will be obtained using low quality models. The thesis presents a methodology supported by KMF that uses the UML specification to compute the design metrics at an early stage of software development. The thesis presents a transformation language called YATL (Yet Another Transformation Language), which was designed and implemented to support the features provided by OMG's Request For Proposal and the future QVT standard. YATL is a hybrid language (a mix of declarative and imperative constructions) designed to answer the Query/Views/Transformations Request For Proposals issued by OMG and to express model transformations as required by the Model Driven Architecture (MDA) approach. Several examples of model transformations, which have been implemented using YATL and the support provided by KMF, are presented. These experiments investigate different knowledge areas as programming languages, visual diagrams and distributed systems. YATL was used to implement the following transformations: * UML to Java mapping * Spider diagrams to OCL mapping * EDOC to Web ServicesEThOS - Electronic Theses Online ServiceGBUnited Kingdo

Model driven language engineering

Modeling is a most important exercise in software engineering and development and one of the current practices is object-oriented (OO) modeling. The Object Management Group (OMG) has defined a standard object-oriented modeling language the Unified Modeling Language (UML). The OMG is not only interested in modeling languages; its primary aim is to enable easy integration of software systems and components using vendor-neutral technologies. This thesis investigates the possibilities for designing and implementing modeling frameworks and transformation languages that operate on models and to explore the validation of source and target models. Specifically, we will focus on OO models used in OMG's Model Driven Architecture (MDA), which can be expressed in terms of UML terms (e.g. classes and associations). The thesis presents the Kent Modeling Framework (KMF), a modeling framework that we developed, and describes how this framework can be used to generate a modeling tool from a model. It then proceeds to describe the customization of the generated code, in particular the definition of methods that allows a rapid and repeatable instantiation of a model. Model validation should include not only checking the well-formedness using OCL constraints, but also the evaluation of model quality. Software metrics are useful means for evaluating the quality of both software development processes and software products. As models are used to drive the entire software development process it is unlikely that high quality software will be obtained using low quality models. The thesis presents a methodology supported by KMF that uses the UML specification to compute the design metrics at an early stage of software development. The thesis presents a transformation language called YATL (Yet Another Transformation Language), which was designed and implemented to support the features provided by OMG's Request For Proposal and the future QVT standard. YATL is a hybrid language (a mix of declarative and imperative constructions) designed to answer the Query/Views/Transformations Request For Proposals issued by OMG and to express model transformations as required by the Model Driven Architecture (MDA) approach. Several examples of model transformations, which have been implemented using YATL and the support provided by KMF, are presented. These experiments investigate different knowledge areas as programming languages, visual diagrams and distributed systems. YATL was used to implement the following transformations: * UML to Java mapping * Spider diagrams to OCL mapping * EDOC to Web Service

A Bayesian Framework for Software Regression Testing

Software maintenance reportedly accounts for much of the total cost associated with developing software. These costs occur because modifying software is a highly error-prone task. Changing software to correct faults or add new functionality can cause existing functionality to regress, introducing new faults. To avoid such defects, one can re-test software after modifications, a task commonly known as regression testing. Regression testing typically involves the re-execution of test cases developed for previous versions. Re-running all existing test cases, however, is often costly and sometimes even infeasible due to time and resource constraints. Re-running test cases that do not exercise changed or change-impacted parts of the program carries extra cost and gives no benefit. The research community has thus sought ways to optimize regression testing by lowering the cost of test re-execution while preserving its effectiveness. To this end, researchers have proposed selecting a subset of test cases according to a variety of criteria (test case selection) and reordering test cases for execution to maximize a score function (test case prioritization). This dissertation presents a novel framework for optimizing regression testing activities, based on a probabilistic view of regression testing. The proposed framework is built around predicting the probability that each test case finds faults in the regression testing phase, and optimizing the test suites accordingly. To predict such probabilities, we model regression testing using a Bayesian Network (BN), a powerful probabilistic tool for modeling uncertainty in systems. We build this model using information measured directly from the software system. Our proposed framework builds upon the existing research in this area in many ways. First, our framework incorporates different information extracted from software into one model, which helps reduce uncertainty by using more of the available information, and enables better modeling of the system. Moreover, our framework provides flexibility by enabling a choice of which sources of information to use. Research in software measurement has proven that dealing with different systems requires different techniques and hence requires such flexibility. Using the proposed framework, engineers can customize their regression testing techniques to fit the characteristics of their systems using measurements most appropriate to their environment. We evaluate the performance of our proposed BN-based framework empirically. Although the framework can help both test case selection and prioritization, we propose using it primarily as a prioritization technique. We therefore compare our technique against other prioritization techniques from the literature. Our empirical evaluation examines a variety of objects and fault types. The results show that the proposed framework can outperform other techniques on some cases and performs comparably on the others. In sum, this thesis introduces a novel Bayesian framework for optimizing regression testing and shows that the proposed framework can help testers improve the cost effectiveness of their regression testing tasks

Modelo de calidad para el software orientado a objetos

El software ha obtenido en la actualidad una gran importancia en todos los ámbitos de la vida cotidiana. Es indudable que la calidad del software juega un papel fundamental en todo desarrollo informático, aunque en ocasiones no se le presta la suficiente atención, quizás debido a los relativamente escasos trabajos relacionados con este tema desarrollados hasta la fecha. En el presente trabajo, se plantea la necesidad de un modelo de calidad completo. Para cubrir esta necesidad se presenta un nuevo modelo de calidad, obtenido tras un estudio pormenorizado de los modelos de calidad existentes, centrado en el paradigma orientado a objetos. Este modelo de calidad muestra cómo la calidad del software se descompone en una serie de factores y éstos, a su vez, se descomponen en un conjunto de criterios medibles utilizando medidas. El modelo incluye un amplio conjunto de medidas, diseñadas especialmente para su aplicación dentro del paradigma orientado a objetos. Para completar el modelo, se ha diseñado un sencillo método de aplicación de este modelo de calidad para que pueda ser utilizado de una forma simple por los desarrolladores de sistemas informáticos orientados a objetos. El modelo de calidad definido se ha validado realizando un juego de experimentos. Estos experimentos han consistido en la aplicación del modelo sobre una serie de desarrollos orientados a objetos. Los resultados obtenidos han demostrado su utilidad práctica para determinar tanto la calidad global de los sistemas, como para identificar aquellas partes del sistema susceptibles de ser mejoradas. Con este trabajo, se llena un importante hueco existente en esta área, pues, en primer lugar, no existen modelos de calidad completos para la orientación a objetos. En segundo lugar, aunque hay medidas para la orientación a objetos, no se han asociado a los atributos que determinan la calidad del software, por lo que su utilidad, tal cual fueron definidas, resulta bastante cuestionable. Para finalizar, nunca se ha asociado un modelo de calidad con una método de aplicación, por lo que su utilidad quedaba considerablemente mermada, quedando a expensas de la habilidad y experiencia del Ingeniero del Software que lo utilizara