Harmfulness of Code Duplication - A Structured Review of the Evidence

Duplication of code has long been thought to decrease changeability of systems, but recently doubts have been expressed whether this is true in general. This is a problem for researchers because it makes the value of research aimed against clones uncertain, and for practitioners as they cannot be sure whether their effort in reducing duplication is well-spent. In this paper we try to shed light on this is-sue by collecting empirical evidence in favor and against the nega-tive effects of duplication on changeability. We go beyond the flat yes/no-question of harmfulness and present an explanatory model to show the mechanisms through which duplication is suspected to affect quality. We aggregate the evidence for each of the causal links in the model. This sheds light on the current state of duplication re-search and helps practitioners choose between the available mitiga-tion strategies

A methodology for the capture and analysis of hybrid data: a case study of program debugging

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Toward Reverse Engineering of VBA Based Excel Spreadsheet Applications

Modern spreadsheet systems can be used to implement complex spreadsheet applications including data sheets, customized user forms and executable procedures written in a scripting language. These applications are often developed by practitioners that do not follow any software engineering practice and do not produce any design documentation. Thus, spreadsheet applications may be very difficult to be maintained or restructured. In this position paper we present in a nutshell two reverse engineering techniques and a tool that we are currently realizing for the abstraction of conceptual data models and business logic models.Comment: In Proceedings of the 2nd Workshop on Software Engineering Methods in Spreadsheets (http://spreadsheetlab.org/sems15/

Teaching programming at a distance: the Internet software visualization laboratory

This paper describes recent developments in our approach to teaching computer programming in the context of a part-time Masters course taught at a distance. Within our course, students are sent a pack which contains integrated text, software and video course material, using a uniform graphical representation to tell a consistent story of how the programming language works. The students communicate with their tutors over the phone and through surface mail. Through our empirical studies and experience teaching the course we have identified four current problems: (i) students' difficulty mapping between the graphical representations used in the course and the programs to which they relate, (ii) the lack of a conversational context for tutor help provided over the telephone, (iii) helping students who due to their other commitments tend to study at 'unsociable' hours, and (iv) providing software for the constantly changing and expanding range of platforms and operating systems used by students. We hope to alleviate these problems through our Internet Software Visualization Laboratory (ISVL), which supports individual exploration, and both synchronous and asynchronous communication. As a single user, students are aided by the extra mappings provided between the graphical representations used in the course and their computer programs, overcoming the problems of the original notation. ISVL can also be used as a synchronous communication medium whereby one of the users (generally the tutor) can provide an annotated demonstration of a program and its execution, a far richer alternative to technical discussions over the telephone. Finally, ISVL can be used to support asynchronous communication, helping students who work at unsociable hours by allowing the tutor to prepare short educational movies for them to view when convenient. The ISVL environment runs on a conventional web browser and is therefore platform independent, has modest hardware and bandwidth requirements, and is easy to distribute and maintain. Our planned experiments with ISVL will allow us to investigate ways in which new technology can be most appropriately applied in the service of distance education

Comprehensibility of UML-based Formal Model – A Series of Controlled Experiments

This paper summarises two controlled experiments conducted on a model that integrates the use of semi-formal notation, the Unified Modelling Language (UML) and a formal notation, B. The experiments assessed the comprehensibility of the model, namely UML-B. The first experiment compared the comprehensibility of a UML-B model and a B model. In the second experiment, the model was compared with an Event-B model, a new generation of B. The experiments assessed the ability of the model to present information and to promote problem domain understanding. The measurement focused on the efficiency in performing the comprehension tasks. The experiments employed a cross-over design and were conducted on third-year and masters students. The results suggest that the integration of semi-formal and formal notations expedites the subjects’ comprehension tasks with accuracy even with limited hours of training