Effect of Introduction of Fault and Imperfect Debugging on Release Time

One of the most important decisions related to the efficient management of testing phase of software development life cycle is to determine when to stop testing and release the software in the market. Most of the testing processes are imperfect once. In this paper first we have discussed an optimal release time problem for an imperfect faultdebugging model due to Kapur et al considering effect of perfect and imperfect debugging separately on the total expected software cost. Next, we proposed a SRGM incorporating the effect of imperfect fault debugging and error generation. The proposed model is validated on a data set cited in literature and a release time problem is formulated minimizing the expected cost subject to a minimum reliability level to be achieved by the release time using the proposed model. Solution method is discussed to solve such class of problem. A numerical illustration is given for both type of release problem and finally a sensitivity analysis is performed

Software Reliability Growth Model with Partial Differential Equation for Various Debugging Processes

Most Software Reliability Growth Models (SRGMs) based on the Nonhomogeneous Poisson Process (NHPP) generally assume perfect or imperfect debugging. However, environmental factors introduce great uncertainty for SRGMs in the development and testing phase. We propose a novel NHPP model based on partial differential equation (PDE), to quantify the uncertainties associated with perfect or imperfect debugging process. We represent the environmental uncertainties collectively as a noise of arbitrary correlation. Under the new stochastic framework, one could compute the full statistical information of the debugging process, for example, its probabilistic density function (PDF). Through a number of comparisons with historical data and existing methods, such as the classic NHPP model, the proposed model exhibits a closer fitting to observation. In addition to conventional focus on the mean value of fault detection, the newly derived full statistical information could further help software developers make decisions on system maintenance and risk assessment

APPLICATION AND REFINEMENTS OF THE REPS THEORY FOR SAFETY CRITICAL SOFTWARE

With the replacement of old analog control systems with software-based digital control systems, there is an urgent need for developing a method to quantitatively and accurately assess the reliability of safety critical software systems. This research focuses on proposing a systematic software metric-based reliability prediction method. The method starts with the measurement of a metric. Measurement results are then either directly linked to software defects through inspections and peer reviews or indirectly linked to software defects through empirical software engineering models. Three types of defect characteristics can be obtained, namely, 1) the number of defects remaining, 2) the number and the exact location of the defects found, and 3) the number and the exact location of defects found in an earlier version. Three models, Musa's exponential model, the PIE model and a mixed Musa-PIE model, are then used to link each of the three categories of defect characteristics with reliability respectively. In addition, the use of the PIE model requires mapping defects identified to an Extended Finite State Machine (EFSM) model. A procedure that can assist in the construction of the EFSM model and increase its repeatability is also provided. This metric-based software reliability prediction method is then applied to a safety-critical software used in the nuclear industry using eleven software metrics. Reliability prediction results are compared with the real reliability assessed by using operational failure data. Experiences and lessons learned from the application are discussed. Based on the results and findings, four software metrics are recommended. This dissertation then focuses on one of the four recommended metrics, Test Coverage. A reliability prediction model based on Test Coverage is discussed in detail and this model is further refined to be able to take into consideration more realistic conditions, such as imperfect debugging and the use of multiple testing phases

Uso do Kanban em um processo de gestão de demandas de manutenção de software por terceiros para um órgão público federal brasileiro

Monografia (graduação)—Universidade de Brasília, Faculdade UnB Gama, 2015.A publicação do manifesto ágil, em 2001, possibilitou o surgimento de novas metodologias de gerenciamento e desenvolvimento menos engessadas e mais dinâmicas, a exemplo temos os frameworks Kanban e Scrum. Ambos frameworks têm como princípio a entrega constante de produto e a participação constante do cliente no processo. Carente dessa mudança, a indústria de desenvolvimento de software não demorou para avaliar as novas propostas, inclusive órgãos públicos federais. O Kanban e o Scrum podem e devem ser adaptados às necessidades específicas de uma organização. O processo de gestão de manutenção de software se difere do processo de desenvolvimento e, entre suas particularidades, destaca-se o fato desse necessitar de maior flexibilidade para agregar as frequentes mudanças, tanto no escopo da requisição, quanto na sequência de implementação. O framework Kanban vem sendo empregado para auxiliar o processo de gestão, possibilitando otimizar o fluxo de trabalho e permitindo determinar iterações, sem o limite de tempo, o que possibilita alterações nas demandas de acordo com a aceitação da instituição. O Principal objetivo deste trabalho foi apoiar a definição de um processo de gestão de demandas de manutenção de software por terceiros para um órgão do governo federal brasileiro, utilizando o Framework Kanban. A pesquisa empregada foi descritiva. Quanto aos procedimentos, realizou-se pesquisas na literatura de empresas que tenham implementado o Kanban, também se realizou o estudo de duas instituições Públicas (TCU e INEP) que utilizam este framework. Afim de aplicar o Kanban no Ministério X, primeiro foi necessário caracteriza-lo e somente então desenvolver as atividades propostas para implementação. Ao fim, foi possível propor uma modelagem do processo de manutenção, e um quadro kanban adaptado as necessidades do Ministério. A Homologação destes e a conclusão da adaptação do framework está atrelada a trabalhos futuros. ___________________________________________________________________________ ABSTRACTThe agile manifest published in 2001, enabled the surface of new maintenance and development methodologies, less dense and more dynamic. It is possible quote Kanban and Scrum as examples. Both frameworks have as a principle the constant delivery of product and the client’s constant participation in the process. Lacking this change, the software development industry did not take to evaluate the new proposals, including federal government agencies. Kanban and Scrum can and should be adapted to the organization’s specific needs. The software maintenance management process is different from the development process and, among its singularities, highlights the fact that the process needs greater flexibility to aggregate the frequent changes both in the scope of the request, as in the implementation order. Kanban framework has been used to assist the management process, allowing to optimize the workflow and allowing to define iterations, without a time limit, which allows changes in demands according to the acceptance of the institution. The mainly objective is support the definition of a software management process for maintenance demands by third parties in Brazilian federal government, using the Kanban Framework. This research is classified as descriptive. As the procedures, held research in the literature of companies that have implemented the Kanban. Also was conducted a study in two public institutions (TCU and INEP) that use this framework. In order to apply the Kanban in the Ministry X, first was necessary characterizes it and only then carry out the activities proposed for implementation. In the end, was possible to propose a modeling of the maintenance process, and kanban board adapted the Ministry of needs. The approval of these and the completion of the adjustment of the framework is linked to future work