As práticas ágeis de desenvolvimento de sistemas de software são, neste trabalho, classificadas sob três aspectos: dependabilidade, domínios do ESSENCE e guidelines para redução de erro humano. A partir dessa classificação, um questionário baseado nas práticas relacionadas aos fatores humanos foi aplicado para desenvolvedores de sistemas de software com diferentes níveis de experiência com o objetivo de avaliar a interferência do ambiente na dependabilidade do sistema de software desenvolvido. O questionário foi respondido por 125 desenvolvedores. Os desenvolvedores foram separados em dois grupos e os grupos foram comparados em relação à percepção de certos guidelines para desenvolvimento de software para cada prática considerada. Os resultados do questionário mostraram que a utilização das práticas ágeis analisadas aumentou fatores que reconhecidamente facilitam a redução do erro humano. / In this work, agile software development practices are categorized using three aspects: reliability, ESSENCEs areas of concern and guidelines for human error reduction. From this categorization, it was applied to software developers with different levels of expertise a questionnaire with practices related to human factors with the goal of evaluating the interference of the environment on the reliability of the developed software. The questionnaire was answered by 125 developers. For every practice considered the developers were separated in two groups and compared in relation to the perception of certain guidelines. The results show that the use of those agile practices increase factors that help reduce human error.

Thesis (DPhil (Informatics))--Cape Peninsula University of Technology, 2018. / Increasingly, organisations in South African and across the world rely on software for various reasons, such as competitiveness and sustainability. The software are either developed in-house or purchased from the shelf. Irrespective of how the software was acquired, they do encounter challenges, from implementation to support, and use stages. The challenges sometimes hinder and are prohibitive to processes and activities that the software is intended to enable and support. Majority of the challenges that are encountered with software are attributed to the fact that they were not tested or appropriately tested before implementation. Some of the challenges has been costly to many organisations, particularly in South Africa. As a result, some organisations have been lacking in their efforts toward growth, competitiveness and sustainability. The challenges manifest from the fact that there are no testing tools and methods that can be easily customised for an organisation’s purposes. As a result, some organisations adopt more tools and methods for the same testing purposes, which has not solved the problem, as the challenges continue among South Africa organisations. Based on the challenges as stated above, this study was undertaken. The aim was to develop a decision support system framework, which can be used for software testing by any organisation, owing to its flexibility for customisation. The interpretivist and inductive approaches were employed. The qualitative methods and the case study design approach were applied. Three South African organisations, a private, public and small to medium enterprise (SME) were used as cases in this study. A set of criteria was used to select the organisations. The analysis of the data was guided by two sociotechnical theories, actor network theory (ANT) and diffusion of innovation (DOI). The theories were complementarily applied because of their different focuses. The actor network theory focuses on actors, which are both human and non-human, heterogeneity of networks, and the relationship between the actors within networks. This includes the interactions that happen at different moments as translated within the heterogeneous networks. Thus, ANT was employed to examine and gain better understanding of the factors that influence software testing in organisations. The DOI focuses on how new (fresh) ideas are diffused in an environment, with particular focus on innovation decision process, which constitute five stages: knowledge, persuasion, decision, implementation and confirmation. Findings from the data analysis of the three cases were further interpreted. Based on the interpretation, a decision support system framework was developed. The framework is intended to be of interest to software developers, software project managers and other stakeholders, most importantly, to provide guide to software testers in their tasks of testing software. Thus, this research is intended to be of interest and benefit to organisations and academic through its theoretical, practical and methodological contribution as detailed in the chapter seven (conclusion). In conclusion, even though this research is rigorous, comprehensive and holistic, there are room for future studies. I would like to propose that future research should be in the areas of measurement of software testing. Also, sociotechnical theories like structuration theory and technology acceptance model should be considered in the analysis of such studies.

Academia and industry expend much effort to predict software defects. Researchers proposed many defect prediction algorithms and metrics. While previous defect prediction techniques often take the author of the code into consideration, none of these techniques build a separate prediction model for each developer. Different developers have different coding styles, commit frequencies, and experience levels, which would result in different defect patterns. When the defects of different developers are combined, such differences are obscured, hurting the prediction performance. This thesis proposes two techniques to improve defect prediction performance: personalized defect prediction and confidence-based hybrid defect prediction. Personalized defect prediction builds a separate prediction model for each developer to predict software defects. Confidence-based hybrid defect prediction combines different models by picking the prediction from the model with the highest confidence. As a proof of concept, we apply the two techniques to classify defects at the file change level. We implement the state-of-the-art change classification as the baseline and compare with the personalized defect prediction approach. Confidence-based defect prediction combines these two models. We evaluate on six large and popular software projects written in C and Java—the Linux kernel, PostgreSQL, Xorg, Eclipse, Lucene and Jackrabbit.

Components are widely seen by software engineers as an important technology to address the "software crisis''. An important aspect of components in other areas of engineering is that system reliability can be estimated from the reliability of the components. We show how commonly proposed methods of reliability estimation and composition for software are inadequate because of differences between the models and the actual software systems, and we show where the assumptions from system reliability theory cause difficulty when applied to software. This thesis provides an approach to reliability that makes it possible, if not currently plausible, to compose component reliabilities so as to accurately and safely determine system reliability. Firstly, we extend previous work on input sub-domains, or partitions, such that our sub-domains can be sampled in a statistically sound way. We provide an algorithm to generate the most important partitions first, which is particularly important when there are an infinite number of input sub-domains. We combine analysis and testing to provide useful reliabilities for the various input sub-domains of a system, or component. This provides a methodology for calculating true reliability for a software system for any accurate statistical distribution of input values. Secondly, we present a calculus for probability density functions that permits accurately modeling the input distribution seen by each component in the system - a critically important issue in dealing with reliability of software components. Finally, we provide the system structuring calculus that allows a system designer to take components from component suppliers that have been built according to our rules and to determine the resulting system reliability. This can be done without access to the actual components. This work raises many issues, particularly about scalability of the proposed techniques and about the ability of the system designer to know the input profile to the level and kind of accuracy required. There are also large classes of components where the techniques are currently intractable, but we see this work as an important first step.

Academia and industry expend much effort to predict software defects. Researchers proposed many defect prediction algorithms and metrics. While previous defect prediction techniques often take the author of the code into consideration, none of these techniques build a separate prediction model for each developer. Different developers have different coding styles, commit frequencies, and experience levels, which would result in different defect patterns. When the defects of different developers are combined, such differences are obscured, hurting the prediction performance. This thesis proposes two techniques to improve defect prediction performance: personalized defect prediction and confidence-based hybrid defect prediction. Personalized defect prediction builds a separate prediction model for each developer to predict software defects. Confidence-based hybrid defect prediction combines different models by picking the prediction from the model with the highest confidence. As a proof of concept, we apply the two techniques to classify defects at the file change level. We implement the state-of-the-art change classification as the baseline and compare with the personalized defect prediction approach. Confidence-based defect prediction combines these two models. We evaluate on six large and popular software projects written in C and Java—the Linux kernel, PostgreSQL, Xorg, Eclipse, Lucene and Jackrabbit.

No description available.

In spite of the fact that software reliability studies have attracted great deal of attention from different disciplines in 1970s, applications of the subject have rarely been involved in the software industry. With the rise of technological advances especially in the military electronics field, reliability of software systems gained importance. In this study, a company in the defense industries is inspected for their abilities and needs regarding software reliability, and an improvement proposal with metrics measurement system is formed. A computer tool is developed for the evaluation of the performance of the improvement proposal. Results obtained via this tool indicate improved abilities in the development of reliable software products.

Thesis (Ph. D. in Software Engineering)--Naval Postgraduate School, Sept. 2004. / Thesis Advisor(s): Luqi. Includes bibliographical references. Also available online.

Orientadores: Mario Jino, Adalberto Nobiato Crespo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-25T04:04:06Z (GMT). No. of bitstreams: 1 Silva_OdairJacintoda_M.pdf: 2238493 bytes, checksum: 120710575da3bbe9052b22a2df5a3a07 (MD5) Previous issue date: 2014 / Resumo: Diversos estudos publicados indicam que a capacidade preditiva dos modelos de confiabilidade de software, que utilizam a informação da cobertura observada durante os testes, é melhor do que a capacidade preditiva dos modelos baseados no domínio do tempo. E, por isso, têm sido propostos por pesquisadores da área como uma alternativa aos modelos baseados no domínio do tempo. Entretanto, para chegar a uma conclusão sobre a superioridade desta classe de modelos é necessário avaliar a sua sensibilidade a variações do perfil operacional. Uma qualidade desejável dos modelos de confiabilidade de software é a de que sua capacidade preditiva não seja afetada por variações no perfil operacional de um software. Esta dissertação avalia, por meio de um experimento, o comportamento de dois modelos de confiabilidade de software que se baseiam na informação de cobertura do código: "Modelo Binomial Baseado em Cobertura" e "Modelo de Falhas Infinitas Baseado em Cobertura". O experimento aplica os modelos nos dados de falhas observados durante a execução de um programa em três perfis operacionais estatisticamente distintos. Adicionalmente, seis modelos de confiabilidade de software tradicionais são utilizados para estimar a confiabilidade do software utilizando os mesmos dados de falhas. Os modelos escolhidos foram: Musa-Okumoto, Musa Básico, Littlewood-Verral Linear, Littlewood-Verral Quadrático, Jelinski-Moranda e Geométrico. Os resultados mostram que a capacidade preditiva dos modelos "Modelo Binomial Baseado em Cobertura" e "Modelo de Falhas Infinitas Baseado em Cobertura" não é afetada com a variação do perfil operacional do software. O mesmo resultado não foi observado nos modelos de confiabilidade de software baseados no domínio do tempo, ou seja, a alteração do perfil operacional influencia a capacidade preditiva desses modelos. Um resultado observado, por exemplo, é de que nenhum dos modelos tradicionais pôde ser utilizado para estimar a confiabilidade do software aplicando os dados de falhas gerados por um dos perfis operacionais / Abstract: Several published studies indicate that the predictive ability of the software reliability models using test coverage information observed during the tests is better than the predictive ability of models based on time domain. And, therefore, have been proposed by researchers as an alternative to models based on time domain. However, to reach a conclusion about the superiority of this class of models is necessary to evaluate their sensitivity to variations in operational profile. A desirable quality of software reliability models is that their predictive ability is not affected by variations in the operational profile of a program. This dissertation analyzes by means of an experiment, the sensitivity of two software reliability models based on code coverage information: "Binomial Model Based on Coverage" and "Infinite Failure Model Based on Coverage". The experiment applies the models to data failures observed during the execution of a program according to three statistically distinct operational profiles. Additionally, six traditional software reliability models were used to estimate the reliability using the same software failure data. The models selected were: Musa-Okumoto, Musa Basic, Littlewood-Verrall Linear, Quadratic Littlewood-Verrall, Jelinski-Moranda and Geometric. The results show that the predictive ability of the models "Binomial Model Based on Coverage" and "Infinite Failure Model Based on Coverage" is not affected by varying the operational profile of the software. The same result was not observed in software reliability models based on time domain, i.e., changing the operational profile influences the predictive ability of these models. A result observed for example is that none of the traditional models could be used to estimate the software reliability using the fault data set generated by one of the operational profiles / Mestrado / Engenharia de Computação / Mestre em Engenharia Elétrica

We present the Hadley model, a formal descriptive model of input and output for modern computer operating systems. Our model is intentionally inspired by the Open Systems Interconnection model of networking; I/O as a process is defined as a set of translations between a set of computer-sensible forms, or layers, of information. To illustrate an initial application domain, we discuss the utility of the Hadley model and a potential associated I/O system as a tool for digital forensic investigators. To illustrate practical uses of the Hadley model we present the Hadley Specification Language, an essentially functional language designed to allow the translations that comprise I/O to be written in a concise format allowing for relatively easy verifiability. To further illustrate the utility of the language we present a read/write Microsoft DOS FAT12 and read-only Linux ext2 file system specification written in the new format. We prove the correctness of the read-only side of these descriptions. We present test results from operation of our HSL-driven system both in user mode on stored disk images and as part of a Linux kernel module allowing file systems to be read. We conclude by discussing future directions for the research.