Estimation of the Scope of Change Propagation in Object- Oriented Programs

When minor modifications need to be made in an object-oriented computer program, they often incur further more changes due to presence of dependency in the codes and the program structure. Yet, to accommodate the required change, there can also be more than one option to carry out the initial modifications. To select the modification option in this context, this thesis proposes a systematic approach to estimate the scope of change propagation of an object-oriented program given some initial modifications. The present Master’s thesis seeks to develop an approach to predict the scope of propagated change through the entities of object-oriented software due to a modification in the software. Despite the previous works that just studied the change propagation in object oriented programs from the aspect of high level entities like classes or from the aspect of UML diagrams, we have studied the finer entities of the object oriented program and the relationships among them. In this regard, this thesis has focused on the calculation of probability of change propagation between each two specific types of entities through the analysis of dependency types among the fundamental entities of object-oriented program and categorization of existing dependencies between each couple of entities. Then, we have defined the priority number concept as a representative scale for the scope of change propagation in software based on the probability rules. The strategy is to first capture the dependency relationships of the entities, pertaining to an object-oriented program via the matrix representation. In this work, we have used Design Structure Matrix to capture and trace dependency among software’s entities. Based on this matrix-based model, the priority number method is proposed and applied to estimate the scope of change propagation by assuming some initial modifications. The core of this method is to estimate the chance of affecting other program entities due to some modified entities and the matrix structure. Finally, the obtained results from a case study have been tested to validate the effectiveness of the change propagation probability numbers and priority number concept

Using requirements and design information to predict volatility in software development

We hypothesise that data about the requirements and design stages of a software development project can be used to make predictions about the subsequent number of development changes that software components will experience. This would allow managers to concentrate time-consuming efforts (such as traceability and staff training) to a few at-risk, cost-effective areas, and may also allow predictions to be made at an earlier stage than is possible using traditional metrics, such as lines of code. Previous researchers have studied links between change-proneness and metrics such as measures of inheritance, size and code coupling. We extend these studies by including measures of requirements and design activity as well. Firstly we develop structures to model the requirements and design processes, and then propose some new metrics based on these models. The structures are populated using data from a case study project and analysed alongside existing complexity metrics to ascertain whether change-proneness can be predicted. Finally we examine whether combining these metrics with existing metrics improves our ability to make predictions about change-proneness. First results show that our metrics can be linked to the quantity of change experienced by components in a software development project (potentially allowing predictions to take place earlier than before) but that best results are obtained by combining existing complexity metrics such as size, or combining existing metrics with our newer metrics.EThOS - Electronic Theses Online ServiceBAE Systems : Engineering and Physical Sciences Research CouncilGBUnited Kingdo