Submitted by Nayara Passos (nayara.passos@ufpe.br) on 2015-03-12T14:07:25Z No. of bitstreams: 2 TESE Juliana de Albuquerque Gonçalves Saraiva.pdf: 2801469 bytes, checksum: 2f35aeb3fe1c0178a717be10adc01c26 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-12T14:07:25Z (GMT). No. of bitstreams: 2 TESE Juliana de Albuquerque Gonçalves Saraiva.pdf: 2801469 bytes, checksum: 2f35aeb3fe1c0178a717be10adc01c26 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2014 / FACEPE, INES / Atualmente, Programao Orientada a Objetos (POO) um dos paradigmas mais utilizados. Complementarmente, a manutenibilidade de software considerada um atributo de software que desempenha um papel importante com relao ao nvel de qualidade. Neste contexto, a Manutenibilidade de Software Orientado a Objetos (MSOO) foi estudada atravs de anos e vrios pesquisadores propuseram um elevado nmero de mtricas para a medir. Como consequncia do nmero e da diversidade de mtricas existentes, alm da no padronizao nas definies e nomenclatura, a tomada de deciso sobre quais mtricas podem ser adotadas para realizar estudos em MSOO difcil. Desta forma, um mapeamento sistemtico foi realizado a fim de encontrar quais mtricas so usadas como indicadores de MSOO. Houve uma seleo inicial de 5175 estudos primrios e 138 artigos foram selecionados, resultando em 568 mtricas encontradas. Analisando as 568 mtricas, foram encontradas inconsistncias na nomenclatura destas mtricas, pois havia mtricas com nomes iguais mas significados diferentes (8 casos envolvendo 17 mtricas) e tambm mtricas com nomes diferentes e significados semelhantes (32 casos envolvendo 214 mtricas). Alm disto, uma categorizao destas mtricas foi proposta, sendo identificadas 7 categorias e 17 subcategorias. Estas categorias representam os cenrios de adoo de mtricas de MSOO. Adicionalmente, um portal web de mtricas foi desenvolvido para fornecer informaes sobre as mtricas para outros pesquisadores e tambm gerar catlogos de mtricas de acordo com o contexto da aplicao das mesmas. Este portal tambm pode ser alimentado sistematicamente por outros pesquisadores que lidam com mtricas de MSOO, fazendo com que os resultados deste trabalho possam representar os primeiros passos para padronizao e compreenso destas mtricas. Por ltimo, um quasi-experimento foi realizado para checar o grau de cobertura do catlogo proposto pela abordagem aqui apresentada quando o mesmo comparado com catlogos sugeridos por especialistas. 90% de cobertura foi obtido e este resultado foi confirmado com 99% de grau de confiana usando o Teste de Wilcoxon. De forma complementar, houve uma pesquisa de opinio para checar se os especialistas acharam catlogo gerado usando a nossa abordagem semelhante ou melhor do que o sugerido por eles. Sendo assim, os resultados da anlise da cobertura dos catlogos pode servir como indcios da utilidade da abordagem proposta para a escolha de mtricas na avaliao de MSOO. / Currently, Object-Oriented Programming (OOP) is one of the most used paradigms. Complementarily, the software maintainability is considered a software attribute that plays an important role in quality level. In this context, the Object-Oriented Software Maintainability (OOSM) has been studied through years, and many researchers have proposed a large number of metrics to measure it. As a consequence of the number and diversity of metrics, beyond the no standardization in metrics definition and naming, the decision-making process about which metrics can be adopted in experiments on OOSM, or even their using in software companies is a difficult task. Therefore, a systematic mapping study was conducted in order to find which metrics are used as indicators in OOSM assessments. There was an initial selection of 5175 primary studies and 138 were selected, resulting in 568 metrics found. Analyzing the 568 metrics, inconsistencies in metrics’ naming were found because there were metrics with the same names but different meanings (8 cases involving 17 metrics) and also, there were metrics with different names, however with similar meanings (32 cases involving 214 metrics). Moreover, a metrics’ categorization has been proposed to facilitate decision-making process about which ones have to be adopted, and 7 categories and 17 subcategories were identified. These categories represent the evaluation scenarios where OOSM metrics should be used. Additionally, a metrics’ web portal was developed to provide information about the metrics collected in this research, and to generate metrics’ catalogs according to the context of their adoption. This portal can also be systematically fed by other researchers that work with OOSM metrics, making the results of this work the first steps towards metrics’ standardization, and the improvement of the metrics’ validation. Finally, a quasi-experiment was conducted to check the coverage index of the catalogs generated using our approach over the catalogs suggested by experts. 90% of coverage was obtained and this result was confirmed with 99% of confidential level using the Wilcoxon Test. Complementarily, a survey was conducted to check the experts’ opinion about the catalog generated by the portal when they were compared by the catalogs suggested by the experts. Thus, the coverage evaluation can be the first evidences of the usefulness of the proposed approach for metrics’ choice in OOSM evaluation.

Context: Early prediction of software cost and quality is important for better software planning and controlling. In early development phases, design complexity metrics are considered as useful indicators of software testing effort and some quality attributes. Although many studies investigate the relationship between design complexity and cost and quality, it is unclear what we have learned from these studies, because no systematic synthesis exists to date. Aim: The research presented in this thesis is intended to contribute for the body of knowledge about cost and quality prediction. A major part of this thesis presents the systematic review that provides detail discussion about state of the art of research on relationship between software design metric and cost and software quality. Method: This thesis starts with a literature review to identify the important complexity dimensions and potential predictors for predicting external software quality attributes are identified. Second, we aggregated Spearman correlation coefficients and estimated odds ratios from univariate logistic regression models from 59 different data sets from 57 primary studies by a tailored meta-analysis approach. At last, it is an attempt to evaluate and explain for disagreement among selected studies. Result: There are not enough studies for quantitatively summarizing relationship between design complexity and development cost. Fault proneness and maintainability is the main focused characteristics that consume 75% total number of studies. Within fault proneness and maintainability studies, coupling and scale are two complexity dimensions that are most frequently used. Vote counting shows evidence about positive impact of some design metrics on these two quality attributes. Meta analysis shows the aggregated effect size of Line of code (LOC) is stronger than those of WMC, RFC and CBO. The aggregated effect sizes of LCOM, DIT and NOC are at trivial to small level. In subgroup analysis, defect collections phase explains more than 50% of observed variation in five out of seven investigated metrics. Conclusions: Coupling and scale metrics are stronger correlated to fault proneness than cohesion and inheritance metrics. No design metrics are stronger single predictors than LOC. We found that there is a strong disagreement between the individual studies, and that defect collection phase is able to partially explain the differences between studies.

Since Web applications are very complex, compared to traditional client/server applications, Web application design with the UML can be obtrusively hard for a modeller. The grounds are that the UML does not define the correct semantics to be able to visualize a web application correctly. This is a qualitative reduction study where we have used interviews and our own experience during the redesign of a UML-modelled e-commerce application with WAE-UML. Using the flow of a case study we have tried to see if we can improve three quality attributes of a complete design. Stakeholder communication reflects the need of unambiguous design artefacts that are easy to understand and that mediate the real message of the use-case. The condition of the design artefacts should provide artefacts that resemble reality and that not are misleading and provide for verification and validation of the requirements. The last attribute maintainability should provide means for easy maintenance and updates. We found that WAE-UML can improve these quality attributes in a design but the impact it has on them is dependent on two major aspects. The first aspect concerns the designers’ judgment of detail in a design. A detailed design can be good considering requirements and use-case traceability and verification, but prohibit communication. Maintainability can also be improved in a detailed design because the diagrams are less abstract and a truer picture of the application. The second aspect is that it depends on the knowledge possessed of the semantics by the people in contact with the design documents. Due to the time aspect the people working in the industry that we interviewed were reluctant to modelling a Web application at all. They thought it would take a long time to learn WAE-UML but also for executing a design phase. / Contact e-mail: miga02@student.bth.se, hean01@student.bth.se

Context: Software architecture is an emerging field and progressively more popular in software engineering. Software architecture has become an essential part in development of software systems. Prototyping is possibly one of the most commonly used learning paradigms in software architecture. Hence, it is reasonable to accept some of the requirements that could be expressed as specific quality attributes for developing and comparative analysis of prototype. In this thesis we deal with software architecture based on different prototypes, where the different platforms have been shared canonical within the software architecture. It also has a good potential for performance intensification to analyze the prototype according to the required quality attributes. Objectives: In this study, we investigate the significance of quality attributes such as performance, maintainability and implementation cost of different software platforms. Mainly, it is focused on integration of prototypes in software architecture. We specifically investigate several challenges being faced by the organizations in the maintainability for addressing the challenges in prototype of network management system using software platforms. Methods: In this study, both theoretical and empirical research methods have been applied. In order to accomplish the goal of this thesis, literature review in this research has performed by studying articles from several sources and also performed snowball sampling method to decrease the chance of missing any relevant article. During literature review, we have analyzed learning structure and workflow of prototypes and then incorporated quality attributes by theoretical analysis. In the experiment part, three prototypes were built by deploying different software platforms such as PHP, JSP and Perl. Each of these prototypes was evaluated with respect to maintainability using twenty five surveys from industrial experts, implementation cost in number of hours and performance in terms of response time. Results: As a result of our study, we have identified different challenges in software architecture and practicing in software prototypes by using different software platforms. By this study we analyze the performance, maintainability and implementation cost for different software platforms. Survey has been conducted to recognize challenges and practices in maintainability of prototypes. We have shown the possibility to achieve better quality attributes given to a certain system. Conclusions: There is trade-off, the best implementation alternative depends on how important the different quality attributes are in a certain situation. / +46 455 38 50 00

Background. Maintainability of software products continues to be an area of im- portance and interest both for practice and research. The time used for maintenance usually exceeds 70% of the whole period of software development process. At present, there is a large number of metrics that have been suggested to indicate the main- tainability of a software product. However, there is a gap in validation of proposed source code metrics and the external quality of software maintainability. Objectives. In this thesis, we aim to catalog the proposed metrics for software maintainability. From this catalog we will validate a subset of commonly proposed maintainability indicators. Methods. Through a literature review with a systematic search and selection ap- proach, we collated maintainability metrics from secondary studies on software main- tainability. A subset of commonly metrics identified in the literature review were validated in a retrospective study. The retrospective study used a large open source software "Elastic Search" as a case. We collected internal source code metrics and a proxy for maintainability of the system for 911 bug fixes in 14 version (11 experi- mental samples, 3 are verification samples) of the product. Results. Following a systematic search and selection process, we identified 11 sec- ondary studies on software maintainability. From these studies we identified 290 source code metrics that are claimed to be indicators of the maintainability of a soft- ware product. We used mean time to repair (MTTR) as a proxy for maintainability of a product. Our analysis reveals that for the "elasticsearch" software, the values of the four indicators LOC, CC, WMC and RFC have the strongest correlation with MTTR. Conclusions. In this thesis, we validated a subset of commonly proposed source code metrics for predicting maintainability. The empirical validation using a popu- lar large-scale open source system reveals that some metrics have shown a stronger correlation with a proxy for maintainability in use. This study provides important empirical evidence towards a better understanding of source code attributes and maintainability in practice. However, a single case and a retrospective study are insufficient to establish a cause effect relation. Therefore, further replications of our study design with more diverse cases can increase the confidence in the predictive ability and thus the usefulness of the proposed metrics.

This study assesses how maintainability can be improved by manual and automatic refactoring strategies. Firstly, the structure of the CSS is important and CSS rules should conform to a certain order depending on their purpose. Secondly, dead code makes files unnecessarily large and more difficult to read. Removing dead code is an important step for improving maintenance. These refactoring strategies were taken from the book CSS Refactoring by Lindstrom. The refactoring strategies were tested on a large CSS code base from an ASP.NET application called AktiveraMera. The structure was manually applied by following a step by step process where each CSS rule was classified and sorted into files and folders. For example, rules styling a specific button were put in a file which is then placed in the \emph{component-styles} folder. All these separate files are then concatenated into one file which is then minimized in order to keep it small when it is later served to the user. The divided structure makes it easier for developers to add new component-, structure-, or browser-specific CSS in the correct place. It also makes it easier to keep refactoring limited and the developer knows all rules that are relevant to a certain element are kept in the same place. The new structure introduced some visual regression. It is difficult to assess how much extra time it adds if all visual regression must be remedied, but some of the changes could probably be ignored while fixing the more egregious changes. Either way, some extra work needs to be done but according to interviewed developers it would probably be worth it. The assessment is that the new structure does improve maintainability. The tool CSS-analyser was then used to find and remove duplicated CSS, a form of dead CSS code, in order to reduce the size of the CSS files. Smaller file size (fewer lines of code) is correlated to readability and by extent maintainability since it is less code to read through and understand. However, while the results did show a reduction in file size it did introduce a lot of very obvious visual regression which means a lot more work. In an industry setting there are often time constraints and if something adds more work it might not be a good strategy. The visual regression was akin to a broken website where the entire layout is changed, so it could not be ignored if it was used on the live application in question. Maintainability can be improved by introducing some structure to the CSS code in the form of a folder structure with sorted and classified CSS rules. Removing dead CSS code is difficult to do automatically without introducing website breaking visual regression. It is much more important to make sure the structure of the CSS is good than to directly try to remove dead code, especially since the structure can make other refactoring strategies more effective.

This thesis studies the use of the functional reactive programming (FRP) framework reactive-banana in a prototype which simulates a part of a Long-Term Evolution (LTE) base station: the Radio Resource Control connection setup procedure. The investigated problem is to determine whether using this FRP framework leads to an implementation with suitable performance and improved maintainability compared to the current implementation. Enhancing the maintainability of the base station software enables quicker and more efficient maintenance activities, which lead to an improved customer satisfaction. Moreover, it means that less programmers need to work on maintenance, so they can work on developing new products instead. In order to compare the use of the FRP paradigm to the one currently used in the base station implementation, the object-oriented programming (OOP) paradigm, a second prototype using this paradigm was also implemented. Having two prototypes implementing the same designed reference model (which is a simplified version of the Radio Resource Control connection setup procedure) enables a relevant comparison of the two paradigms. The two prototypes were then compared in terms of performance and maintainability. The maintainability evaluation consisted in using both software metrics and experts’ assessment, as this has been proven to be the most efficient way to evaluate software maintainability. Four experts were asked to fill in a questionnaire after reviewing the code of the two implementations. The comparison of the two prototypes indicates that the FRP prototype is more maintainable than the OOP one, but the OOP prototype has better performances than the FRP one. Moreover, the performance of the FRP prototype during the conducted tests indicates that such an implementation of the FRP paradigm is not suitable for a real base station.

Denna rapport har sitt ursprung i det kodefaktoriseringsarbete som utfärdats våren 2013 som examensarbete i dataingenjörsprogrammet vid Örebro Universitet. Arbetet utfärdades på Nethouse i Örebro, och hade stort fokus på koddesign och kodkvalitet. I rapporten diskuteras vilka faktorer som påverkar hur underhållbar och läsbar en kod är, men också hur man på ett rimligt sätt kan utvärdera och mäta kodkvalitet. Den teoretiska biten blandas med den praktiska, där läsaren introduceras för ett flertal metoder, och hur dessa sedan implementerades i det faktiska projektet som Nethouse tillhandahöll. / This report has its origins in the code refactoring work issued in spring 2013 as a Degree Project in the Computer Engineering Programme, at Örebro University. The work took place at Nethouse in Örebro, and had a major focus on code design, and code quality. The report discusses the factors that affect how maintainable and readable a code is, but also how to reasonably evaluate and measure code quality. The theory is mixed with the practical, where the reader is introduced to a variety of methods, and how these were then implemented in the actual project that Nethouse provided.

A Engenharia de Software tem desenvolvido técnicas e métodos para apoiar o desenvolvimento de software confiável, flexível, com baixo custo de desenvolvimento e fácil manutenção. A avaliação da manutenibilidade contribui para fornecer meios para produzir software com alta qualidade. Este trabalho apresenta um experimento controlado para avaliar a manutenibilidade entre as abordagens de web services: RESTful e SOAP-WSDL. Esta avaliação foi conduzida usando 3 programas implementados na linguagem de programação Java e com a mesma arquitetura. Com base na arquitetura projetada, os web services desenvolvidos foram utilizados como objetos em estudos de caso, possibilitando avaliar e comparar a sua manutenibilidade. Os resultados obtidos demonstraram relações entre as informações sobre o custo e a qualidade dos serviços web, que contribuíram para esclarecer os critérios para a obtenção de uma boa relação entre o custo da manutenção e a evolução dos serviços web. Para concluir, os resultados indica que os web services RESTful são mais manuteníveis do lado do servidor, e os web services SOAP-WSDL são mais manuteníveis do lado do cliente. Os estudos realizados no experimento controlado são promissores e podem auxiliar na redução de custo na manutenção dos serviços web, melhorando dessa forma a qualidade do software no geral / Software Engineering has developed techniques and methods to support the development of reliable software, exible, low development cost and easy maintenance. The evaluation of maintainability contributes in this direction, providing the means to produce software with high quality. This paper presents an controlled experiment to evaluate the maintainability between the approaches of web services: RESTful and SOAP-WSDL. This evaluation was conducted using four programs implemented in the Java programming language, using the same architecture. Based on the designed architecture, Web services were developed as objects used in case studies, allowing to evaluate and compare its maintainability. The results showed relationships between the information on the cost and quality of web services, which contributed to clarify the criteria for obtaining a good relationship between the cost of maintenance and evolution of web services. In conclusion, the results indicate the RESTful web services are more maintainable server side in contrast to the SOAP-WSDL web services are more maintainable client side. Studies in controlled experiments are promising and may help reduce the maintenance cost of web services, thus improving overall software quality

A geração de produtos de sucesso está associada ao cumprimento dos anseios e desejos dos consumidores. Diversos fatores caracterizam esses anseios, sendo que um grupo de fatores possui especial característica, esse grupo abrange a confiabilidade, a mantenabilidade e a segurança. A gestão desses três fatores implica num olhar profundo em todo ciclo de vida do produto e não somente no projeto, na manufatura, ou na fase de testes funcionais. O projeto que segue busca discutir a implementação de um sistema de gestão para confiabilidade, mantenabilidade e segurança em empresas que desenvolvem produtos com fins lucrativos, mantendo profunda atenção as diretrizes da engenharia simultânea. Serão abordados aspectos dessa implementação, primeiramente definindo o que deve ser gerido, as razões pelas quais se deve buscar essa gestão, em qual estrutura organizacional o mecanismo de gestão deve ser aplicado, quais ferramentas de gestão são pertinentes e como essas ferramentas podem ser implementadas, ressaltando que cuidados merecem atenção e que resultados são esperados. Por fim será apresentado um caso de implementação de uma das ferramentas mais importantes para o sistema de gestão, o sistema FRACAS, \"Failure Reporting, Analysis and Corrective Action System\", que organiza e padroniza a coleta de dados, possibilita análises e fundamenta a tomada de ações de melhoria. Para o desenvolvimento de toda a discussão serão abordados temas diversos como o ciclo de vida dos produtos, projetos, programas, qualidade, sistemas de informação, tecnologias de banco de dados e obviamente confiabilidade, mantenabilidade e segurança. O estudo de caso partirá de um produto já existente que possua dados de campo, seguindo para a construção de um sistema de informação capaz de coletar, organizar, filtrar e pré-analisar as informações. O principal objetivo do trabalho é gerar diretrizes para empresas que desenvolvem produtos que exijam grande esforço de engenharia na otimização de seu processo de decisão, mostrando algumas opções para controlar suas operações, seus programas e projetos no âmbito da confiabilidade, mantenabilidade, disponibilidade e segurança. / The creation of successful products is linked with the ability to reach longings and desires of costumers. Several factors compose these desires and a group of factors have a special characteristic, this group embraces reliability, maintainability and safety. The management of these three factors carries in a deep look of the entire product\'s life cycle and not only in design, manufacture or in functional test phase. The following work intend discuss an implementation of a management system for reliability, maintainability and safety in companies that develop products seeking profit and keeping intense attention to rules from concurrent engineering. Will be discussed aspects of this implementation, firstly defining what should be managed, the reasons to manage, what kind of organizational structure should control this management system, what management tools are relevant and how these tools can be implemented, what special attention any aspect needs and what results are expected. Finally will be presented an implementation case of one of most important tool for the management system, the system FRACAS, \"Failure Reporting, Analysis and Corrective Action System\", that organizes and standardizes the data collection, making some analysis possible and creating basis for the decision making process. During the development of all this discussion a broad number of subjects will be pointed, like product\'s life cycle, designs, projects, quality, information systems, data base technology e obviously reliability, maintainability and safety. The case will start from a preexistent product that already have available field data, following to construction of an information system capable to collect, organize, filter and pre-analyze the information. The main goal of this work is to orientate companies that develop products that demand huge engineering efforts in optimization of making decisions process, showing some options to control their operations, their programs and projects, concerning reliability, maintainability, availability and safety.