Category Archives: Publication

A Dual Model of Open Source License Growth

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Abstract: Every open source project needs to decide on an open source license. This decision is of high economic relevance: Just which license is the best one to help the project grow and attract a community? The most common question is: Should the project choose a restrictive (reciprocal) license or a more permissive one? As an important step towards answering this question, this paper analyses actual license choice and correlated project growth from ten years of open source projects. It provides closed analytical models and finds that around 2001 a reversal in license choice occurred from restrictive towards permissive licenses.

Keywords: Open source; open source license; software license; open source project growth

Reference: Gottfried Hofmann, Dirk Riehle, Carsten Kolassa, Wolfgang Mauerer. “A Dual Model of Open Source License Growth.” In Proceedings of the 9th International Conference on Open Source Systems (OSS 2013). Springer Verlag, 2013, to appear.

The paper is available as a PDF file.

A Model of Product Features in Commercial Open Source Software

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Abstract: Commercial open source software has become an important part of the packaged software product industry. This paper provides a model of individual product features, rather than full-fledged business models, and their perceived value to customers. The model is the result of a three-iteration study, including interview analysis, literature review and the implementation of an empirical survey. Companies can use the feature model to determine their products and business model.

Keywords: Commercial open source; software product features

Reference: Florian Weikert, Dirk Riehle. “A Model of Commercial Open Source Software Product Features.” In Proceedings of the 4th International Conference on Software Business (ICSOB 2013). Springer Verlag, 2013, to appear.

The paper is available as a PDF file.

Planned Inner Source: Code Reuse Across Profit-Center Boundaries (in German)

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Abstract: Wiederverwendung von Softwarekomponenten verspricht, Softwareentwicklung schneller und günstiger zu machen und die Ergebnisqualität zu steigern. Trotz diverser methodischer Ansätze ist es für viele Softwareentwicklungsorganisationen schwierig geblieben, diese Ziele auch nur ansatzweise zu erreichen. Vor diesem Hintergrund bietet „Inner Source“, die Verwendung von Open-Source-Praktiken in der firmeninternen Softwareentwicklung, neue Chancen. Inner-Source-Software ist Software, die innerhalb eines Unternehmens über Profit-Center-Grenzen hinweg in Gemeinschaftsarbeit entwickelt wird und von allen Abteilungen genutzt werden kann. In diesem Artikel stellen wir die bisher gewonnenen Erfahrungen mit Inner-Source-Entwicklung dar, definieren organisatorische Gestaltungsmöglichkeiten und prognostizieren die Entstehung von Inner-Source-Organisationen, einer neuen Form der Organisation für die Wiederverwendung.

Keywords: Open source; inner source; software code reuse; knowledge sharing; firm-internal open source; open collaboration

Reference: Dirk Riehle, Detlef Kips. Geplanter Inner Source: Ein Weg zur Profit-Center-übergreifenden Wiederverwendung. Friedrich-Alexander University Erlangen-Nürnberg Technical Report CS-2012-05. Erlangen, Germany: 2012.

The paper is available as a PDF file.

Developer Belief vs. Reality: The Case of the Commit Size Distribution

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Abstract: The design of software development tools follows from what the developers of such tools believe is true about software development. A key aspect of such beliefs is the size of code contributions (commits) to a software project. In this paper, we show that what tool developers think is true about the size of code contributions is different by more than an order of magnitude from reality. We present this reality, called the commit size distribution, for a large sample of open source and selected closed source projects. We suggest that these new empirical insights will help improve software development tools by aligning underlying design assumptions closer with reality.

Keywords: Commit size; commit size distribution; code contribution; open source; closed source; software engineering; tool usability

Reference: Dirk Riehle, Carsten Kolassa, Michel A. Salim. “Developer Belief vs. Reality: The Case of the Commit Size Distribution.” In Proceedings of Software Engineering 2012 (SE ’12). Springer Verlag, 2012. Page 59-70.

The paper is available as a PDF file. The survey used in the paper is also available as a PDF file.

Business Risks and Governance of Open Source in Software Products (in German)

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Titel: Geschäftsrisiken und Governance von Open-Source in Softwareprodukten

Zusammenfassung: In fast jedem Softwareprodukt, auch in großer Standardsoftware, sind heute Open-Source-Komponenten enthalten. Die Hersteller dieser Software müssen die Geschäftsrisiken, die mit der Integration von Open-Source-Software in kommerzielle Produkte verbunden sind, verstehen und vernünftig managen. Dieser Artikel zeigt ein Modell verschiedener rechtlicher, technischer und sozialer Risiken auf, die durch unkontrollierten Einsatz von Open-Source-Software entstehen und erläutert ausgewählte Erfolgsmethoden der Open-Source-Governance, die von führenden Firmen angewandt werden. Das Modell ist das Analyseergebnis von fünf mit großen deutschen Softwareherstellern geführten Interviews sowie weiterer Literaturrecherche.

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Design and Implementation of the Sweble Wikitext Parser: Unlocking the Structured Data of Wikipedia

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Abstract: The heart of each wiki, including Wikipedia, is its content. Most machine processing starts and ends with this content. At present, such processing is limited, because most wiki engines today cannot provide a complete and precise representation of the wiki’s content. They can only generate HTML. The main reason is the lack of well-defined parsers that can handle the complexity of modern wiki markup. This applies to MediaWiki, the software running Wikipedia, and most other wiki engines. This paper shows why it has been so difficult to develop comprehensive parsers for wiki markup. It presents the design and implementation of a parser for Wikitext, the wiki markup language of MediaWiki. We use parsing expression grammars where most parsers used no grammars or grammars poorly suited to the task. Using this parser it is possible to directly and precisely query the structured data within wikis, including Wikipedia. The parser is available as open source from http://sweble.org.

Keywords: Wiki, Wikipedia, Wiki Parser, Wikitext Parser, Parsing Expression Grammar, PEG, Abstract Syntax Tree, AST, WYSIWYG, Sweble.

Reference: Hannes Dohrn and Dirk Riehle. “Design and Implementation of the Sweble Wikitext Parser: Unlocking the Structured Data of Wikipedia.” In Proceedings of the 7th International Symposium on Wikis and Open Collaboration (WikiSym 2011). ACM Press, 2011. Page 72-81.

The paper is available as a PDF file (preprint).

Technical Report on WOM: An Object Model for Wikitext

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Abstract: Wikipedia is a rich encyclopedia that is not only of great use to its contributors and readers but also to researchers and providers of third party software around Wikipedia. However, Wikipedia’s content is only available as Wikitext, the markup language in which articles on Wikipedia are written, and whoever needs to access the content of an article has to implement their own parser or has to use one of the available parser solutions. Unfortunately, those parsers which convert Wikitext into a high-level representation like an abstract syntax tree (AST) define their own format for storing and providing access to this data structure. Further, the semantics of Wikitext are only defined implicitly in the MediaWiki software itself. This situation makes it difficult to reason about the semantic content of an article or exchange and modify articles in a standardized and machine-accessible way. To remedy this situation we propose a markup language, called XWML, in which articles can be stored and an object model, called WOM, that defines how the contents of an article can be read and modified.

Keywords: Wiki, Wikipedia, Wikitext, Wikitext Parser, Open Source, Sweble, Mediawiki, Mediawiki Parser, XWML, HTML, WOM

Reference: Hannes Dohrn and Dirk Riehle. WOM: An Object Model for Wikitext. University of Erlangen, Technical Report CS-2011-05 (July 2011).

The technical report is available as a PDF file.

Controlling and Steering Open Source Projects

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The IEEE just published a short version of the “control points and steering mechanisms” article. Here is the abstract. Please see the original for more details.

Abstract: Open source software has become an important part of the software business. In a 2009 survey, Forrester Research found that 46 percent of all responding enterprises were using or implementing open source software. Moreover, in 2009, the Gartner Group estimated that by 2012, at least 80 percent of all software product firms will use open source software. Thus, it’s important to understand how software product firms depend on open source and how they manage that dependency to meet their business goals. There are three main types of software product firms. [...]

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Lessons Learned from Using Design Patterns in Industry Projects

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Abstract: Design patterns help in the creative act of designing, implementing, and documenting software systems. They have become an important part of the vocabulary of experienced software developers. This article reports about the author’s experiences and lessons learned with using and applying design patterns in industry projects. The article not only discusses how using patterns benefits the design of software systems, but also how firms can benefit further from developing a firm-specific design language and how firms can motivate and educate developers to learn and develop this shared language.

Keywords: Design pattern, pattern language, design language, design communication, design collaboration, design implementation, design documentation.

Reference: Dirk Riehle. “Lessons Learned from Using Design Patterns in Industry Projects.” In Transactions on Pattern Languages of Programming II, LNCS 6510. Springer-Verlag, 2011. Page 1-15.

The paper is available as a PDF file.

Micro-Blogging Adoption in the Enterprise: An Empirical Analysis

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Abstract: Given the increasing interest in using social software for company-internal communication and collaboration, this paper examines drivers and inhibitors of micro-blogging adoption at the workplace. While nearly one in two companies is currently planning to introduce social software, there is no empirically validated research on employees’ adoption. In this paper, we build on previous focus group results and test our research model in an empirical study using Structural Equation Modeling. Based on our findings, we derive recommendations on how to foster adoption. We suggest that micro-blogging should be presented to employees as an efficient means of communication, personal brand building, and knowledge management. In order to particularly promote content contribution, privacy concerns should be eased by setting clear rules on who has access to postings and for how long they will be archived.

Reference: Valentin Schöndienst, Hanna Krasnova, Oliver Günther, and Dirk Riehle. “Micro-Blogging Adoption in the Enterprise: An Empirical Analysis.” In Proceedings of the 10th International Conference on Wirtschaftsinformatik (WI 2011). Page 931-940.

The paper is available in PDF form. You may also like the prior paper “Modeling Micro-Blogging Adoption in the Enterprise” as well as my “patterns of effective tweeting”.