Adaptive reuse of Libre software systems for supporting on-line collaboration

In this paper, the adaptive reuse of Plone; an open source content management system is described. In one instance, Plone has been used as the backbone of a collaboration and communication support infrastructure within a large research project. In the other, Plone has been used as the main web-presence of a specialist group of the British Computer Society. This paper analyses the benefits and problems of reusing Plone to support collaboration. Based on this reuse experience, a more systematic approach to supporting Plone reuse is proposed. This approach takes into account the special case of reuse support relevant to open source software developments

Migrating ExcelForms to the .NET framework

ExcelForms is a front end Excel-based application that supports Forms/3, a research language based on the spreadsheet paradigm, end-user software engineering features. The old implementation of ExcelForms performed poorly, and was considered unstable, not robust, and not scalable enough for our users' needs. This project addresses these issues by implementing ExcelForms on the .NET framework

Interactive, visual fault localization support for end-user programmers

End-user programmers are writing an unprecedented number of programs, primarily using languages and environments that incorporate a number of interactive and visual programming techniques. To help these users debug these programs, we have developed an entirely visual, interactive approach to fault localization. This paper presents the approach. We also present the results of a think-aloud study that examined the interactive, human-centric issues that arise in end-user debugging using a fault localization strategy. Our results provide insights into the contributions such strategies can make to the end-user debugging process.Keywords: visual fault localization, debugging, end-user software engineering, slicing, form-based visual programs, testing, end-user programmin

Scaling up an end-user dependability framework for spreadsheets

The WYSIWYT (What You See is What You Test) methodology applies formal analysis and testing techniques to the spreadsheet paradigm. So far the methodology has been applied to a research spreadsheet prototype, Forms/3. However, this prototype lacks the mathematical libraries, referential functions, ranges, and macros of commercial spreadsheets like Excel and Lotus 1-2-3. Study subjects are also accustomed to the grid-like interface of commercial spreadsheet packages and many spreadsheets of interest are available in the Excel file format. This project addresses these areas by implementing WYSIWYT in Microsoft Excel and Gnumeric

Scaling up an end-user dependability framework for spreadsheets

The WYSIWYT (What You See is What You Test) methodology applies formal analysis and testing techniques to the spreadsheet paradigm. So far the methodology has been applied to a research spreadsheet prototype, Forms/3. However, this prototype lacks the mathematical libraries, referential functions, ranges, and macros of commercial spreadsheets like Excel and Lotus 1-2-3. Study subjects are also accustomed to the grid-like interface of commercial spreadsheet packages and many spreadsheets of interest are available in the Excel file format. This project addresses these areas by implementing WYSIWYT in Microsoft Excel and Gnumeric

Automated model-based spreadsheet debugging

Spreadsheets are interactive data organization and calculation programs that are developed in spreadsheet environments like Microsoft Excel or LibreOffice Calc. They are probably the most successful example of end-user developed software and are utilized in almost all branches and at all levels of companies. Although spreadsheets often support important decision making processes, they are, like all software, prone to error. In several cases, faults in spreadsheets have caused severe losses of money. Spreadsheet developers are usually not educated in the practices of software development. As they are thus not familiar with quality control methods like systematic testing or debugging, they have to be supported by the spreadsheet environment itself to search for faults in their calculations in order to ensure the correctness and a better overall quality of the developed spreadsheets. This thesis by publication introduces several approaches to locate faults in spreadsheets. The presented approaches are based on the principles of Model-Based Diagnosis (MBD), which is a technique to find the possible reasons why a system does not behave as expected. Several new algorithmic enhancements of the general MBD approach are combined in this thesis to allow spreadsheet users to debug their spreadsheets and to efficiently find the reason of the observed unexpected output values. In order to assure a seamless integration into the environment that is well-known to the spreadsheet developers, the presented approaches are implemented as an extension for Microsoft Excel. The first part of the thesis outlines the different algorithmic approaches that are introduced in this thesis and summarizes the improvements that were achieved over the general MBD approach. In the second part, the appendix, a selection of the author's publications are presented. These publications comprise (a) a survey of the research in the area of spreadsheet quality assurance, (b) a work describing how to adapt the general MBD approach to spreadsheets, (c) two new algorithmic improvements of the general technique to speed up the calculation of the possible reasons of an observed fault, (d) a new concept and algorithm to efficiently determine questions that a user can be asked during debugging in order to reduce the number of possible reasons for the observed unexpected output values, and (e) a new method to find faults in a set of spreadsheets and a new corpus of real-world spreadsheets containing faults that can be used to evaluate the proposed debugging approaches

Test Reuse in the Spreadsheet Paradigm

end users to perform many important tasks. Despite their perceived simplicity, spreadsheets often contain faults. Furthermore, users modify their spreadsheets frequently, which can render previously correct spreadsheets faulty. To address this problem, we previously introduced a visual approach by which users can systematically test their spreadsheets, see where new tests are required after changes, and request automated generation of potentially useful test inputs. To date, however, this approach has not taken advantage of previously developed test cases, which means that users of the approach cannot benefit, when re-testing following changes, from prior testing efforts. We have therefore been investigating ways to add support for test re-use into our spreadsheet testing methodology. In this paper we present a test re-use strategy for spreadsheets, and the algorithms that implement it, and describe their integration into our spreadsheet testing methodology. We report results of a case study examining the application of this strategy