Investigación en Progreso: Estudio del Comportamiento Dinámico del Diseño de Sistemas de Información basado en Redes Complejas

La medición de sistemas de información es una de las tareas más importantes dentro de la Ingeniería del Software ya que permite caracterizarlos y estudiarlos eficientemente. Se han desarrollado decenas de métricas aunque principalmente orientadas a aspectos estáticos. Este proyecto tiene como objetivo desarrollar un proceso de análisis que permita estudiar y evaluar el comportamiento dinámico de un sistema software desde el punto de vista del diseño de sistemas

An Analysis of Early Software Reliability Improvement Techniques

This research explores early life cycle software reliability prediction models or techniques to predict the reliability of software prior to writing code, and a method for increasing or improving the reliability of software products early in the development life cycle. Five prediction models and two development techniques are examined. Each model is statically analyzed in terms of availability of data early in the life cycle, ease of data collection, and whether data is currently collected. One model and the two techniques satisfied those requirements and are further analyzed for their ability to predict or improve software reliability. While the researchers offer no significant statistical results of the model\u27s ability to predict software reliability, important conclusions are drawn about the cost and time savings of using inspections as a means of improving software reliability. The results indicate that the current software development paradigm needs to be changed to use the Cleanroom Software Development Process for fixture software development. This proactive approach to developing reliable software saves development and testing costs. One obvious benefit of this research is that cost savings realized earlier in the software development cycle have a dramatic effect on making software development practices better and more efficient

System design and the cost of architectural complexity

Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 159-166).Many modern systems are so large that no one truly understands how they work. It is well known in the engineering community that architectural patterns (including hierarchies, modules, and abstraction layers) should be used in design because they play an important role in controlling complexity. These patterns make a system easier to evolve and keep its separate portions within the bounds of human understanding so that distributed teams can operate independently while jointly fashioning a coherent whole. This study set out to measure the link between architectural complexity (the complexity that arises within a system due to a lack or breakdown of hierarchy or modularity) and a variety of costs incurred by a development organization. A study was conducted within a successful software firm. Measures of architectural complexity were taken from eight versions of their product using techniques recently developed by MacCormack, Baldwin, and Rusnak. Significant cost drivers including defect density, developer productivity, and staff turnover were measured as well. The link between cost and complexity was explored using a variety of statistical techniques. Within this research setting, we found that differences in architectural complexity could account for 50% drops in productivity, three-fold increases in defect density, and order-of-magnitude increases in staff turnover. Using the techniques developed in this thesis, it should be possible for firms to estimate the financial cost of their complexity by assigning a monetary value to the decreased productivity, increased defect density, and increased turnover it causes. As a result, it should be possible for firms to more accurately estimate the potential dollar-value of refactoring efforts aimed at improving architecture.by Daniel J. Sturtevant.Ph.D

A Study on Software Testability and the Quality of Testing in Object-Oriented Systems

Software testing is known to be important to the delivery of high-quality systems, but it is also challenging, expensive and time-consuming. This has motivated academic and industrial researchers to seek ways to improve the testability of software. Software testability is the ease with which a software artefact can be effectively tested. The first step towards building testable software components is to understand the factors – of software processes, products and people – that are related to and can influence software testability. In particular, the goal of this thesis is to provide researchers and practitioners with a comprehensive understanding of design and source code factors that can affect the testability of a class in object oriented systems. This thesis considers three different views on software testability that address three related aspects: 1) the distribution of unit tests in relation to the dynamic coupling and centrality of software production classes, 2) the relationship between dynamic (i.e., runtime) software properties and class testability, and 3) the relationship between code smells, test smells and the factors related to smells distribution. The thesis utilises a combination of source code analysis techniques (both static and dynamic), software metrics, software visualisation techniques and graph-based metrics (from complex networks theory) to address its goals and objectives. A systematic mapping study was first conducted to thoroughly investigate the body of research on dynamic software metrics and to identify issues associated with their selection, design and implementation. This mapping study identified, evaluated and classified 62 research works based on a pre-tested protocol and a set of classification criteria. Based on the findings of this study, a number of dynamic metrics were selected and used in the experiments that were then conducted. The thesis demonstrates that by using a combination of visualisation, dynamic analysis, static analysis and graph-based metrics it is feasible to identify central classes and to diagrammatically depict testing coverage information. Experimental results show that, even in projects with high test coverage, some classes appear to be left without any direct unit testing, even though they play a central role during a typical execution profile. It is contended that the proposed visualisation techniques could be particularly helpful when developers need to maintain and reengineer existing test suites. Another important finding of this thesis is that frequently executed and tightly coupled classes are correlated with the testability of the class – such classes require larger unit tests and more test cases. This information could inform estimates of the effort required to test classes when developing new unit tests or when maintaining and refactoring existing tests. An additional key finding of this thesis is that test and code smells, in general, can have a negative impact on class testability. Increasing levels of size and complexity in code are associated with the increased presence of test smells. In addition, production classes that contain smells generally require larger unit tests, and are also likely to be associated with test smells in their associated unit tests. There are some particular smells that are more significantly associated with class testability than other smells. Furthermore, some particular code smells can be seen as a sign for the presence of test smells, as some test and code smells are found to co-occur in the test and production code. These results suggest that code smells, and specifically certain types of smells, as well as measures of size and complexity, can be used to provide a more comprehensive indication of smells likely to emerge in test code produced subsequently (or vice versa in a test-first context). Such findings should contribute positively to the work of testers and maintainers when writing unit tests and when refactoring and maintaining existing tests

Contribution to Quality-driven Evolutionary Software Development process for Service-Oriented Architectures

The quality of software is a key element for the successful of a system. Currently, with the advance of the technology, consumers demand more and better services. Models for the development process have also to be adapted to new requirements. This is particular true in the case of service oriented systems (domain of this thesis), where an unpredictable number of users can access to one or several services. This work proposes an improvement in the models for the software development process based on the theory of the evolutionary software development. The main objective is to maintain and improve the quality of software as long as possible and with the minimum effort and cost. Usually, this process is supported on methods known in the literature as agile software development methods. Other key element in this thesis is the service oriented software architecture. Software architecture plays an important role in the quality of any software system. The Service oriented architecture adds the service flexibility, the services are autonomous and compact assets, and they can be improved and integrated with better facility. The proposed model in this thesis for evolutionary software development makes emphasis in the quality of services. Therefore, some principles of evolutionary development are redefined and new processes are introduced, such as: architecture assessment, architecture recovery and architecture conformance. Every new process will be evaluated with case studies considering quality aspects. They have been selected according to the market demand, they are: the performance, security and evolutionability. Other aspects could be considered of the same way than the three previous, but we believe that these quality attributes are enough to demonstrate the viability of our proposal