Delayed failure of software components using stochastic testing

The present research investigates the delayed failure of software components and addresses the problem that the conventional approach to software testing is unlikely to reveal this type of failure. Delayed failure is defined as a failure that occurs some time after the condition that causes the failure, and is a consequence of long-latency error propagation. This research seeks to close a perceived gap between academic research into software testing and industrial software testing practice by showing that stochastic testing can reveal delayed failure, and supporting this conclusion by a model of error propagation and failure that has been validated by experiment. The focus of the present research is on software components described by a request-response model. Within this conceptual framework, a Markov chain model of error propagation and failure is used to derive the expected delayed failure behaviour of software components. Results from an experimental study of delayed failure of DBMS software components MySQL and Oracle XE using stochastic testing with random generation of SQL are consistent with expected behaviour based on the Markov chain model. Metrics for failure delay and reliability are shown to depend on the characteristics of the chosen experimental profile. SQL mutation is used to generate negative as well as positive test profiles. There appear to be few systematic studies of delayed failure in the software engineering literature, and no studies of stochastic testing related to delayed failure of software components, or specifically to delayed failure of DBMS. Stochastic testing is shown to be an effective technique for revealing delayed failure of software components, as well as a suitable technique for reliability and robustness testing of software components. These results provide a deeper insight into the testing technique and should lead to further research. Stochastic testing could provide a dependability benchmark for component-based software engineering

Economic data bank management in a developing nation

This dissertation describes the results of a research project which was undertaken at Loughborough University of Technology. The basic objectives of the research project were: (1) to investigate the management elements required for organising the development of an Economic Data Bank (EDB), with particular emphasis on the requirements of a developing nation; (2) to investigate the sociological, political and technical implications associated with organising the development of an EDB in a developing nation. A theoretical framework was established for this study. This was dene after an extensive search and review of literature was performed in the areas of data and data base management systems, management information systems, and computer technology in general. [Continues.

Vulnerability discovery in multiple version software systems: open source and commercial software systems

Department Head: L. Darrell Whitley.2007 Summer.Includes bibliographical references (pages 80-83).The vulnerability discovery process for a program describes the rate at which the vulnerabilities are discovered. A model of the discovery process can be used to estimate the number of vulnerabilities likely to be discovered in the near future. Past studies have considered vulnerability discovery only for individual software versions, without considering the impact of shared code among successive versions and the evolution of source code. These affecting factors in vulnerability discovery process need to be taken into account estimate the future software vulnerability discovery trend more accurately. This thesis examines possible approaches for taking these factors into account in the previous works. We implemented these factors on vulnerability discovery process. We examine a new approach for quantitatively vulnerability discovery process, based on shared source code measurements among multiple version software system. The applicability of the approach is examined using Apache HTTP Web server and Mysql DataBase Management System (DBMS). The result of this approach shows better goodness of fit than fitting result in the previous researches. Using this revised software vulnerability discovery process, the superposition effect which is an unexpected vulnerability discovery in the previous researches could be determined by software discovery model. The multiple software vulnerability discovery model (MVDM) shows that vulnerability discovery rate is different with single vulnerability discovery model's (SVDM) discovery rate because of newly considered factors. From these result, we create and applied new SVDM for open source and commercial software. This single vulnerability process is examined, and the model testing result shows that SVDM can be an alternative modeling. The modified vulnerability discovery model will be presented for supporting previous researches' weakness, and the theoretical modeling will be discuss for more accurate explanation

Is Your Learned Query Optimizer Behaving As You Expect? A Machine Learning Perspective

The current boom of learned query optimizers (LQO) can be explained not only by the general continuous improvement of deep learning (DL) methods but also by the straightforward formulation of a query optimization problem (QOP) as a machine learning (ML) one. The idea is often to replace dynamic programming approaches, widespread for solving QOP, with more powerful methods such as reinforcement learning. However, such a rapid "game change" in the field of QOP could not pass without consequences - other parts of the ML pipeline, except for predictive model development, have large improvement potential. For instance, different LQOs introduce their own restrictions on training data generation from queries, use an arbitrary train/validation approach, and evaluate on a voluntary split of benchmark queries. In this paper, we attempt to standardize the ML pipeline for evaluating LQOs by introducing a new end-to-end benchmarking framework. Additionally, we guide the reader through each data science stage in the ML pipeline and provide novel insights from the machine learning perspective, considering the specifics of QOP. Finally, we perform a rigorous evaluation of existing LQOs, showing that PostgreSQL outperforms these LQOs in almost all experiments depending on the train/test splits

TLAD 2010 Proceedings:8th international workshop on teaching, learning and assesment of databases (TLAD)

This is the eighth in the series of highly successful international workshops on the Teaching, Learning and Assessment of Databases (TLAD 2010), which once again is held as a workshop of BNCOD 2010 - the 27th International Information Systems Conference. TLAD 2010 is held on the 28th June at the beautiful Dudhope Castle at the Abertay University, just before BNCOD, and hopes to be just as successful as its predecessors.The teaching of databases is central to all Computing Science, Software Engineering, Information Systems and Information Technology courses, and this year, the workshop aims to continue the tradition of bringing together both database teachers and researchers, in order to share good learning, teaching and assessment practice and experience, and further the growing community amongst database academics. As well as attracting academics from the UK community, the workshop has also been successful in attracting academics from the wider international community, through serving on the programme committee, and attending and presenting papers.This year, the workshop includes an invited talk given by Richard Cooper (of the University of Glasgow) who will present a discussion and some results from the Database Disciplinary Commons which was held in the UK over the academic year. Due to the healthy number of high quality submissions this year, the workshop will also present seven peer reviewed papers, and six refereed poster papers. Of the seven presented papers, three will be presented as full papers and four as short papers. These papers and posters cover a number of themes, including: approaches to teaching databases, e.g. group centered and problem based learning; use of novel case studies, e.g. forensics and XML data; techniques and approaches for improving teaching and student learning processes; assessment techniques, e.g. peer review; methods for improving students abilities to develop database queries and develop E-R diagrams; and e-learning platforms for supporting teaching and learning

Development of a knowledge-based system for the repair and maintenance of concrete structures

PhD ThesisInformation Technology (IT) can exploit strategic opportunities for new ways of facilitating information and data exchange and the exchange of expert and specialist opinions in any field of engineering. Knowledge-Based Systems are sophisticated computer programs which store expert knowledge on specific subject and are applied to a broad range of engineering problems. Integrated Database applications have facilitated the essential capability of storing data to overcome an increasing information malaise. Integrating these areas of Information Technology (IT) can be used to bring a group of experts in any field of engineering closer together by allowing them to communicate and exchange information and opinions. The central feature of this research study is the integration of these hitherto separate areas of Information Technology (IT). In this thesis an adaptable Graphic User Interface Centred application comprising a Knowledge-Based Expert System (DEMARECEXPERT), a Database Management System (REPCON) and Evaluation program (ECON) alongside visualisation technologies is developed to produce an innovative platform which will facilitate and encourage the development of knowledge in concrete repair. Diagnosis, Evaluation, MAintenance and REpair of Concrete structures (DEMAREQ is a flexible application which can be used in four modes of Education, Diagnostic, Evaluation and Evolution. In the educational mode an inexperienced user can develop a better understanding of the repair of concrete technology by navigating through a database of textual and pictorial data. In the diagnostic mode, pictures and descriptive information taken from the database and performance of the expert system (DEMAREC-EXPERT) are used in a way that makes problem solving and decision making easier. The DEMAREC-EXPERT system is coupled to the REPCON (as an independent database) in order to provide the user with recommendations related to the best course required for maintenance and in the selection of materials and methods for the repair of concrete. In the evaluation mode the conditions observed are described in unambiguous terms that can be used by the user to be able to take engineering and management actions for the repair and maintenance of the structure. In the evolution mode of the application, the nature of distress, repair and maintenance of concrete structures within the extent of the database management system has been assessedT. he new methodology of data/usere valuation could have wider implications in many knowledge rich areas of expertise. The benefit of using REPCON lies in the enhanced levels of confidence which can be attributed to the data and to contribution of that data. Effectively, REPCON is designed to model a true evolution of a field of expertise but allows that expertise to move on in faster and more structured manner. This research has wider implications than within the realm of concrete repair. The methodology described in this thesis is developed to provide tecýnology transfer of information from experts, specialists to other practitioners and vice versa and it provides a common forum for communication and exchange information between them. Indeed, one of the strengths of the system is the way in which it allows the promotion and relegation of knowledge according to the opinion of users of different levels of ability from expert to novice. It creates a flexible environment in which an inexperienced user can develop his knowledge in maintenance and concrete repair structures. It is explained how an expert and a specialist can contribute his experience and knowledge towards improving and evolving the problem solving capability of the application