Configuring and Assembling Information Retrieval based Solutions for Software Engineering Tasks.

Information Retrieval (IR) approaches are used to leverage textual or unstructured data generated during the software development process to support various software engineering (SE) tasks (e.g., concept location, traceability link recovery, change impact analysis, etc.). Two of the most important steps for applying IR techniques to support SE tasks are preprocessing the corpus and configuring the IR technique, and these steps can significantly influence the outcome and the amount of effort developers have to spend for these maintenance tasks. We present the use of Genetic Algorithms (GAs) to automatically configure and assemble an IR process to support SE tasks. The approach named IR-GA determines the (near) optimal solution to be used for each step of the IR process without requiring any training. We applied IR-GA on three different SE tasks and the results of the study indicate that IR-GA outperforms approaches previously used in the literature, and that it does not significantly differ from an ideal upper bound that could be achieved by a supervised approach and a combinatorial approach

A Review on Web Page Classification

With the increase in digital documents on the world wide web and an increase in the number of webpages and blogs which are common sources for providing users with news about current events, aggregating and categorizing information from these sources seems to be a daunting task as the volume of digital documents available online is growing exponentially. Although several benefits can accrue from the accurate classification of such documents into their respective categories such as providing tools that help people to find, filter and analyze digital information on the web amongst others. Accurate classification of these documents into their respective categories is dependent on the quality of training dataset which is dependent on the preprocessing techniques. Existing literature in this area of web page classification identified that better document representation techniques would reduce the training and testing time, improve the classification accuracy, precision and recall of classifier. In this paper, we give an overview of web page classification with an in-depth study of the web classification process, while at the same time making awareness of the need for an adequate document representation technique as this helps capture the semantics of document and-also contribute to reduce the problem of high dimensionality

A Review on Web Page Classification

With the increase in digital documents on the world wide web and an increase in the number of webpages and blogs which are common sources for providing users with news about current events, aggregating and categorizing information from these sources seems to be a daunting task as the volume of digital documents available online is growing exponentially. Although several benefits can accrue from the accurate classification of such documents into their respective categories such as providing tools that help people to find, filter and analyze digital information on the web amongst others. Accurate classification of these documents into their respective categories is dependent on the quality of training dataset which is dependent on the preprocessing techniques. Existing literature in this area of web page classification identified that better document representation techniques would reduce the training and testing time, improve the classification accuracy, precision and recall of classifier. In this paper, we give an overview of web page classification with an in-depth study of the web classification process, while at the same time making awareness of the need for an adequate document representation technique as this helps capture the semantics of document and-also contribute to reduce the problem of high dimensionality

From Bugs to Decision Support – Leveraging Historical Issue Reports in Software Evolution

Software developers in large projects work in complex information landscapes and staying on top of all relevant software artifacts is an acknowledged challenge. As software systems often evolve over many years, a large number of issue reports is typically managed during the lifetime of a system, representing the units of work needed for its improvement, e.g., defects to fix, requested features, or missing documentation. Efficient management of incoming issue reports requires the successful navigation of the information landscape of a project. In this thesis, we address two tasks involved in issue management: Issue Assignment (IA) and Change Impact Analysis (CIA). IA is the early task of allocating an issue report to a development team, and CIA is the subsequent activity of identifying how source code changes affect the existing software artifacts. While IA is fundamental in all large software projects, CIA is particularly important to safety-critical development. Our solution approach, grounded on surveys of industry practice as well as scientific literature, is to support navigation by combining information retrieval and machine learning into Recommendation Systems for Software Engineering (RSSE). While the sheer number of incoming issue reports might challenge the overview of a human developer, our techniques instead benefit from the availability of ever-growing training data. We leverage the volume of issue reports to develop accurate decision support for software evolution. We evaluate our proposals both by deploying an RSSE in two development teams, and by simulation scenarios, i.e., we assess the correctness of the RSSEs' output when replaying the historical inflow of issue reports. In total, more than 60,000 historical issue reports are involved in our studies, originating from the evolution of five proprietary systems for two companies. Our results show that RSSEs for both IA and CIA can help developers navigate large software projects, in terms of locating development teams and software artifacts. Finally, we discuss how to support the transfer of our results to industry, focusing on addressing the context dependency of our tool support by systematically tuning parameters to a specific operational setting

Combining Fault Localization with Information Retrieval: an Analysis of Accuracy and Performance for Bug Finding

Debugging is a key activity in the software development process. It has been used extensively by developers to attempt to localize faults, while enhancing the quality and performance of software in general. There has been a significant amount of study in developing and enhancing fault localization techniques, which are used in assisting developers to locate faults within a body of code. However, identifying fault locations using individual techniques is not always effective; combining different techniques, which represent distinct forms of analysis, might help to overcome this issue. There has been a very limited amount of research that suggests that combining more than one approach to fault localization may have benefits, principally because information from different sources is included in the localization process. In this thesis, I attempt to more precisely address the question of whether combining different fault localization techniques can more effectively and efficiently find faults in code, when contrasted with a single technique. To answer this, I have carried out experiments that combine the use of three fault localization techniques: Information Retrieval (IR), Spectrum Based Fault Localization (SBFL), and Text Based Search. These techniques are representative of both dynamic and static fault localization. My hypothesis is that a combination of dynamic and static fault localization analysis can assist developers in better fault localization. I have evaluated the various combinations of techniques in identifying faults against real-world programs, Defects4j, where 395 faults and bug reports have been analyzed. The experimental results demonstrate that the combination of three techniques (SBFL, Text Search, and IR) is the most accurate, with 86.84% accuracy for 343 faults located from a total of 395. This finding contributes positively towards concretely recommending techniques for assisting developers in locating faults in code. Guidelines are provided on which combination of techniques, with maximal accuracy of result, should be applied especially when there is no prior knowledge about the fault

Search-Based Software Maintenance and Testing

2012 - 2013In software engineering there are many expensive tasks that are performed during development and maintenance activities. Therefore, there has been a lot of e ort to try to automate these tasks in order to signi cantly reduce the development and maintenance cost of software, since the automation would require less human resources. One of the most used way to make such an automation is the Search-Based Software Engineering (SBSE), which reformulates traditional software engineering tasks as search problems. In SBSE the set of all candidate solutions to the problem de nes the search space while a tness function di erentiates between candidate solutions providing a guidance to the optimization process. After the reformulation of software engineering tasks as optimization problems, search algorithms are used to solve them. Several search algorithms have been used in literature, such as genetic algorithms, genetic programming, simulated annealing, hill climbing (gradient descent), greedy algorithms, particle swarm and ant colony. This thesis investigates and proposes the usage of search based approaches to reduce the e ort of software maintenance and software testing with particular attention to four main activities: (i) program comprehension; (ii) defect prediction; (iii) test data generation and (iv) test suite optimiza- tion for regression testing. For program comprehension and defect prediction, this thesis provided their rst formulations as optimization problems and then proposed the usage of genetic algorithms to solve them. More precisely, this thesis investigates the peculiarity of source code against textual documents written in natural language and proposes the usage of Genetic Algorithms (GAs) in order to calibrate and assemble IR-techniques for di erent software engineering tasks. This thesis also investigates and proposes the usage of Multi-Objective Genetic Algorithms (MOGAs) in or- der to build multi-objective defect prediction models that allows to identify defect-prone software components by taking into account multiple and practical software engineering criteria. Test data generation and test suite optimization have been extensively investigated as search- based problems in literature . However, despite the huge body of works on search algorithms applied to software testing, both (i) automatic test data generation and (ii) test suite optimization present several limitations and not always produce satisfying results. The success of evolutionary software testing techniques in general, and GAs in particular, depends on several factors. One of these factors is the level of diversity among the individuals in the population, which directly a ects the exploration ability of the search. For example, evolutionary test case generation techniques that employ GAs could be severely a ected by genetic drift, i.e., a loss of diversity between solutions, which lead to a premature convergence of GAs towards some local optima. For these reasons, this thesis investigate the role played by diversity preserving mechanisms on the performance of GAs and proposed a novel diversity mechanism based on Singular Value Decomposition and linear algebra. Then, this mechanism has been integrated within the standard GAs and evaluated for evolutionary test data generation. It has been also integrated within MOGAs and empirically evaluated for regression testing. [edited by author]XII n.s

Towards a holistic framework for software artefact consistency management

A software system is represented by different software artefacts ranging from requirements specifications to source code. As the system evolves, artefacts are often modified at different rates and times resulting in inconsistencies, which in turn can hinder effective communication between stakeholders, and the understanding and maintenance of systems. The problem of the differential evolution of heterogeneous software artefacts has not been sufficiently addressed to date as current solutions focus on specific sets of artefacts and aspects of consistency management and are not fully automated. This thesis presents the concept of holistic artefact consistency management and a proof-of-concept framework, ACM, which aim to support the consistent evolution of heterogeneous software artefacts while minimising the impact on user choices and practices and maximising automation. The ACM framework incorporates traceability, change impact analysis, change detection, consistency checking and change propagation mechanisms and is designed to be extensible. The thesis describes the design, implementation and evaluation of the framework, and an approach to automate trace link creation using machine learning techniques. The framework evaluation uses six open source systems and suggests that managing the consistency of heterogeneous artefacts may be feasible in practical scenarios

Configuring Topic Models for Software Engineering Tasks in TraceLab

A number of approaches in traceability link recovery and other software engineering tasks incorporate topic models, such as Latent Dirichlet Allocation (LDA). Although in theory these topic models can produce very good results if they are configured properly, in reality their potential may be undermined by improper calibration of their parameters (e.g., number of topics, hyper-parameters), which could potentially lead to sub-optimal results. In our previous work we addressed this issue and proposed LDA-GA, an approach that uses Genetic Algorithms (GA) to find a near-optimal configuration of parameters for LDA, which was shown to produce superior results for traceability link recovery and other tasks than reported ad-hoc configurations. LDA-GA works by optimizing the coherence of topics produced by LDA for a given dataset. In this paper, we instantiate LDA-GA as a TraceLab experiment, making publicly available all the implemented components, the datasets and the results from our previous work. In addition, we provide guidelines on how to extend our LDA-GA approach to other IR techniques and other software engineering tasks using existing TraceLab components

Configuring topic models for software engineering tasks in tracelab

Abstract—A number of approaches in traceability link recovery and other software engineering tasks incorporate topic models, such as Latent Dirichlet Allocation (LDA). Although in theory these topic models can produce very good results if they are configured properly, in reality their potential may be undermined by improper calibration of their parameters (e.g., number of topics, hyper-parameters), which could potentially lead to sub-optimal results. In our previous work we addressed this issue and proposed LDA-GA, an approach that uses Genetic Algorithms (GA) to find a near-optimal configuration of parameters for LDA, which was shown to produce superior results for traceability link recovery and other tasks than reported ad-hoc configurations. LDA-GA works by optimizing the coherence of topics produced by LDA for a given dataset. In this paper, we instantiate LDA-GA as a TraceLab experiment, making publicly available all the implemented components, the datasets and the results from our previous work. In addition, we provide guidelines on how to extend our LDA-GA approach to other IR techniques and other software engineering tasks using existing TraceLab components. Index Terms—Configurable, TraceLab, experiments, LDA, genetic algorithm, traceabilit