Survey of Research on Software Clones

This report summarizes my overview talk on software clone detection research. It first discusses the notion of software redundancy, cloning, duplication, and similarity. Then, it describes various categorizations of clone types, empirical studies on the root causes for cloning, current opinions and wisdom of consequences of cloning, empirical studies on the evolution of clones, ways to remove, to avoid, and to detect them, empirical evaluations of existing automatic clone detector performance (such as recall, precision, time and space consumption) and their fitness for a particular purpose, benchmarks for clone detector evaluations, presentation issues, and last but not least application of clone detection in other related fields. After each summary of a subarea, I am listing open research questions

Software Visualization for Reverse Engineering

This article describes the Bauhaus tool suite as a concrete example for software visua-lization in reverse engineering, re-engineering, and software maintenance. Results from a recent survey on software visualization in these domains are reported. According to this survey, Bauhaus can indeed be considered a typical representative of these domains regarding the way software artifacts are visualized. Specific requirements for software visualizations are drawn from both the specific example and the survey.

Robust Parsing of Cloned Token Sequences

Token-based clone detection techniques are known for theirscalability, high recall, and robustness against syntax errors andincomplete code. They, however, may yield clones that aresyntactically incomplete and they know very little about the syntacticstructure of their reported clones. Hence, their results cannotimmediately be used for automated refactorings or syntactic filtersfor relevance.This paper explores techniques of robust parsing to parse codefragments reported by token-based clone detectors to determine whetherthe clones are syntactically complete and what kind of syntacticelements they contain.This knowledge can be used to improve the precision of token-basedclone detection

06301 Abstracts Collection -- Duplication, Redundancy, and Similarity in Software

From 23.07.06 to 26.07.06, the Dagstuhl Seminar 06301 ``Duplication, Redundancy, and Similarity in Software\u27\u27 was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

The multi-criteria assessment of ecosystem services at a landscape level to support decision-making in regional and landscape planning

The growing pressure on natural resources and biodiversity has led to a widespread acknowledgement of the services nature provides for humans. The appropriate representation of the benefits of sustainable land use in decision-making is still a challenge and tools that facilitate land use planning processes are needed. The dissertation presents a multicriteria assessment approach for a qualitative estimation of regional potentials to provide ecosystem services. This approach has been applied in several case studies in Saxony, Eastern Germany and Brasil. The ecosystem services concept builts the methodological framework for the assessment as it offers a universal approach to evaluate the impact of Land use/ Land cover change (LULCC) on human well-being. Since standardized methodical approaches for ecosystem services assessment at the landscape level are lacking, a particular requirement was to conceive a method that is easily transferable to other case study areas. Further the method should enable the use of existing and easily available environmental data, and it should be transparent for stakeholders and decision makers. The results of our study show that the combination of selected ecosystem services and land cover data such as CORINE Land Cover (CLC) can contribute to regional planning by communicating the effect of LULCC on ecosystem services, especially when applied as an evaluation basis in the tool GISCAME. The approach supports also the assessment of the performance of a region to provide ecosystem services and the comparison of regions towards this aspect. In the discussion section, the limitations of the developed approach are discussed. Main sources of uncertainty are related to coarse land cover data, lacking knowledge on the provision of ecosystem services at a landscape scale, and the difficulty to make relevant the ecosystem services concept in regional planning processes

Comparison and Evaluation of Clone Detection Tools

Many techniques for detecting duplicated source code (software clones) have been proposed in the past. However, it is not yet clear how these techniques compare in terms of recall and precision as well as space and time requirements. This paper presents an experiment that evaluates six clone detectors based on eight large C and Java programs (altogether almost 850 KLOC). Their clone candidates were evaluated by one of the authors as an independent third party. The selected techniques cover the whole spectrum of the state-of-the-art in clone detection. The techniques work on text, lexical and syntactic information, software metrics, and program dependency graphs