@article {1566,
	title = {Open Source Community Processes: Implications on Micro and Macro Level},
	journal = {it {\textendash} Information Technology},
	volume = {55},
	number = {5},
	year = {2013},
	pages = {189-194},
	abstract = {In this paper, we will discuss the existence and form of open source community processes, whether they differ between projects, and whether they have any implications on both micro and macro level. We will take a look at how different processes can impact the work and the resulting quality within projects, as well as on macro or project level outcomes like success or efficiency. We will also present as well as validate a research model to explain process adoption and implications.},
	attachments = {https://flosshub.org/sites/flosshub.org/files/itit.2013.1010.pdf},
	author = {Koch, Stefan}
}
@article {Koch2008345,
	title = {Effort modeling and programmer participation in open source software projects},
	journal = {Information Economics and Policy (Empirical Issues in Open Source Software)},
	volume = {20},
	number = {4},
	year = {2008},
	note = {"Using a two-step approach, first a detailed case study on one project, GNOME, will be undertaken, then a large data set retrieved from a project hosting site, SourceForge.net, will be used to validate the results."

CVS was the main source of data

"e-mails sent to the different project discussion lists were identified as an additional source of information especially on communication and coordination besides the CVS-repository"

basic counts were calculated for developer discussion levels},
	month = {12/2008},
	pages = {345 - 355},
	abstract = {This paper develops models for programmer participation and effort estimation in open source software projects and employs the results to assess the efficiency of open source software creation. Successful development of such models will be important for decision makers of various kinds. We propose hypotheses based on a prior case study on manpower function and effort modeling. A large data set retrieved from a project repository is used to test these hypotheses. The main results are that if Norden-Rayleigh-based approaches are used, they need to be complemented in order to account for the addition of new features during a product life cycle, and that programmer-participation based effort models result in distinctly lower estimations of effort than those based on output metrics, such as lines of code.},
	keywords = {cvs, developers, email, email archives, gnome, lines of code, scm, Software repository mining, source code, sourceforge},
	issn = {0167-6245},
	doi = {DOI: 10.1016/j.infoecopol.2008.06.004},
	url = {http://www.sciencedirect.com/science/article/B6V8J-4SSND1J-1/2/c857fa1493e19aa7fe4297dedb077b3a},
	attachments = {https://flosshub.org/sites/flosshub.org/files/KochEffortModeling.pdf},
	author = {Koch, Stefan}
}
@conference {562,
	title = {Open Source Project Categorization Based on Growth Rate Analysis and Portfolio Planning Methods},
	booktitle = {OSS2008: Open Source Development, Communities and Quality (IFIP 2.13)},
	series = {IFIP International Federation for Information Processing},
	volume = {275/2008},
	year = {2008},
	month = {2008///},
	pages = {375 - 380},
	publisher = {Springer},
	organization = {Springer},
	chapter = {35},
	abstract = {In this paper, we propose to arrive at an assessment and evaluation of open source projects based on an analysis of their growth rates in several aspects. These include code base, developer number, bug reports and downloads. Based on this analysis and assessment, a well-known portfolio planning method, the BCG matrix, is employed for arriving at a very broad classification of open source projects. While this approach naturally results in a loss of detailed information, a top-level categorization is in some domains necessary and of interest.
},
	issn = {978-0-387-09683-4},
	doi = {http://dx.doi.org/10.1007/978-0-387-09684-1_35},
	attachments = {https://flosshub.org/sites/flosshub.org/files/Open\%20Source\%20Project\%20Categorization.pdf},
	author = {Koch, Stefan and Stix, Volker}
}
@conference {624,
	title = {Exploring the Effects of Coordination and Communication Tools on the Efficiency of Open Source Projects using Data Envelopment Analysis},
	booktitle = {OSS2007: Open Source Development, Adoption and Innovation (IFIP 2.13)},
	series = {IFIP International Federation for Information Processing },
	volume = {234/2007},
	year = {2007},
	note = {"based on the date january 8, 2007, we selected the 30 most often downloaded projects from Sourceforge.net"},
	month = {2007///},
	pages = {97 - 108},
	publisher = {Springer},
	organization = {Springer},
	chapter = {8},
	abstract = {In this paper, we propose to explore possible benefits of communication and coordination tools in open source projects using data envelopment analysis (DEA), a general method for efficiency comparisons. DEA offers several advantages: It is a non-parametric optimization method without any need for the user to define any relations between different factors or a production function, can account for economies or diseconwhile omies of scale, and is able to deal with multi-input, multi-output systems in which the factors have different scales. Using a data set of 30 open source project retrieved from SourceForge.net, we demonstrate the application of DEA, showing that the efficiency of the projects is in general relatively high. Regarding the effects of tool employment on the efficiency of projects, the results were surprising: Most of the possible tools, and overall usage, showed a negative relationship to efficiency.
},
	keywords = {metadata, sourceforge},
	issn = {978-0-387-72485-0},
	doi = {http://dx.doi.org/10.1007/978-0-387-72486-7_8},
	attachments = {https://flosshub.org/sites/flosshub.org/files/Exploring\%20the\%20Effects\%20Coodination.pdf},
	author = {Koch, Stefan}
}
@article {64,
	title = {Study~of~Available~Tools },
	year = {2007},
	institution = {FLOSSmetrics},
	type = {EU Framework deliverable},
	isbn = {D1.1},
	url = {http://flossmetrics.org/sections/deliverables/docs/deliverables/WP1/D1.1- Study_of_Available_Tools.pdf},
	author = {Antoniades, Ionannis~ and Samoladas, Ioannis and Sowe, Sulayman K. and Gregorio Robles and Koch, Stefan and Fraczek, Ksenia and Hadzisalihovic, Anis}
}
@conference {685,
	title = {Conceptual Modelling as a New Entry in the Bazaar: The Open Model Approach},
	booktitle = {OSS2006: Open Source Systems (IFIP 2.13)},
	series = {IFIP International Federation for Information Processing},
	year = {2006},
	pages = {9 - 20},
	publisher = {Springer},
	organization = {Springer},
	abstract = {The present contribution proposes to transfer the main principles of open source software development to a new context: conceptual modelling; an activity closely related to software development. The goal of the proposed {\textquotedblleft}open model{\textquotedblright} approach is to collaboratively develop reference models for everyone to copy, use and refine in a public process. We briefly introduce conceptual modelling and reference models, discuss the cornerstones of an open modelling process, and propose a procedure for initiating, growing and sustaining an open model project. The paper concludes with a discussion of potential benefits and pitfalls.
},
	doi = {http://dx.doi.org/10.1007/0-387-34226-5_2},
	attachments = {https://flosshub.org/sites/flosshub.org/files/Conceptual\%20Modelling\%20as\%20a\%20New\%20Entry.pdf},
	author = {Koch, Stefan and Strecker, Stefan and Frank, Ulrich}
}
@conference {740,
	title = {Evolution of Open Source Software Systems {\textendash} A Large-Scale Investigation},
	booktitle = {OSS2005: Open Source Systems },
	year = {2005},
	pages = {148-153},
	abstract = {In this paper, the evolution of a large sample of open source software projects will be analysed. The evolution of commercial systems has been an issue that has long been a center of research, thus a coherent theoretical framework of software evolution has been developed and empirically tested. Therefore these results can be used to compare the situation in open source projects to the evolution of commercial projects. This allows to assess whether the underlying software process indeed significantly differs. The data collection methodology relying on a large software repository and the respective source code control systems is described, and an overview on the collected data on several thousand projects is given. The evolutionary behaviour is explored using both a linear and a quadratic model, with the quadratic model significantly outperforming the linear one. The most interesting fact is that while in the mean the growth rate is decreasing over time according to the l...},
	url = {http://pascal.case.unibz.it/handle/2038/863},
	author = {Koch, Stefan}
}
@conference {744,
	title = {Using the Iterated Prisoner{\textquoteright}s Dilemma for Explaining the Evolution of Cooperation in Open Source Communities},
	booktitle = {OSS2005: Open Source Systems },
	year = {2005},
	pages = {186-191},
	abstract = {Software development, and especially open source projects, typically involve repeated interactions between participants and groups of participants. We propose to analyse this situation by means of the standard model for the evolution of cooperation, the iterated prisoner{\textquoteright}s dilemma. The prisoner{\textquoteright}s dilemma is a well-known model for a two-person game, in which each side can choose to either cooperate or defect, and in which the payoffs are arranged in a defined hierarchy (e.g. the highest payoff is achieved by defecting while the other player cooperates). As a first step, the prisoner{\textquoteright}s dilemma needs to be formulated for the open source development model, i.e. what constitutes cooperation, playing defect and payoffs. Then, computer simulations using a population of stochastic reactive strategies can be applied, using a strategy{\textquoteright}s payoff as fitness measure for determining its frequency in the next generation. As a further extension, the effects of misinterpretation of other...},
	url = {http://pascal.case.unibz.it/handle/2038/1559},
	author = {Eckert, Daniel and Koch, Stefan and Mitl{\"o}hner, Johann}
}
@article {1077,
	title = {Profiling an Open Source Project Ecology and Its Programmers},
	journal = {Electronic Markets},
	volume = {14},
	year = {2004},
	month = {6/2004},
	pages = {77 - 88},
	abstract = {While many successful and well-known open source projects produce output of high quality, a general assessment of this development paradigm is still missing. In this paper, an online community of both small and large, successful and failed projects and their programmers is analysed mainly using the version-control data of each project, also according to their productivity and estimation of expended effort. As the results show, there are indeed significant differences between this cooperative development model and the commercial organization of work in the areas explored. Both open source software projects in their size and their programmers{\textquoteright} effort differ significantly, and the evolution of projects{\textquoteright} size over time seems in part to contradict the laws of software evolution proposed for commercial systems. Both the inequality of effort distribution between programmers and an increasing number of developers in a project do not lead to a decrease in productivity, opposing Brooks{\textquoteright}s Law. Effort estimation based on the COCOMO model for commercial organizations shows a large amount of effort expended for the projects, while a more general Norden-Rayleigh modeling shows a distinctly smaller expenditure. This proposes that either a highly efficient development is achieved by this self-organizing cooperative and highly decentralized form of work, or that the participation of users besides programming tasks is enormous and constitutes an economic factor of large proportions. },
	keywords = {affiliation network, brooks law, cocomo, effort estimation, evolution, productivity, project success, scm, size, time, version control},
	issn = {1422-8890},
	doi = {10.1080/10196780410001675031},
	author = {Koch, Stefan}
}
@proceedings {131,
	title = {Remote analysis and measurement of libre software systems by means of the CVSanaly tool},
	year = {2004},
	address = {Edinburgh, Scotland},
	abstract = {Libre (free, open source) software is one of the paradigmatic cases where heavy use of telematic tools and user-driven software development are key points. This paper proposes a methodology for measuring and analyzing remotely big libre software projects using publicly-available data from their version control repositories. By means of a tool called CVSAnalY that has been implemented following this methodology, measurements and analyses can be made in an automatic and non-intrusive way, providing real-time and historical data about the project and its contributors.},
	attachments = {https://flosshub.org/sites/flosshub.org/files/robles-koch-barahona_cvsanaly.pdf},
	author = {Gregorio Robles and Koch, Stefan and Jesus M. Gonzalez-Barahona}
}
@article {1117,
	title = {Effort, co-operation and co-ordination in an open source software project: GNOME},
	journal = {Information Systems Journal},
	volume = {12},
	year = {2002},
	note = {"Also retrieved by a Perl script were the postings to the relevant discussion lists including the sender, the subject, time and complete text. For analysis of the posting behaviour of the programmers, the short name that each programmer uses for checkins had to be matched to the full name or email address used for postings. For 175 persons, this has been possible using several regular expressions with human check-up."},
	month = {01/2002},
	pages = {27 - 42},
	abstract = {This paper presents results from research into open source projects from a software engineering perspective. The research methodology employed relies on public data retrieved from the CVS repository of the GNOME project and relevant discussion groups. This methodology is described, and results concerning the special characteristics of open source software development are given. These data are used for a first approach to estimating the total effort to be expended.},
	keywords = {cvs, discussion, effort estimation, gnome},
	issn = {1365-2575},
	doi = {10.1046/j.1365-2575.2002.00110.x},
	author = {Koch, Stefan and Schneider, Georg}
}
@article {flosswp6,
	title = {Results From Software Engineering Research Into Open Source Development Projects Using Public Data},
	number = {22},
	year = {2000},
	institution = {Diskussionspapiere zum T{\"a}tigkeitsfeld Informationsverarbeitung und Informationswirtschaft},
	type = {Discussion Paper},
	abstract = {This paper presents first results from research into open source projects from a software engineering perspective. The research methodology employed relies on public data retrieved from the CVS-repository of the GNOME project and relevant discussion groups. This methodology is described in detail and some of the results concerning the special characteristics of open source software development are given.},
	attachments = {https://flosshub.org/sites/flosshub.org/files/koch-ossoftwareengineering.pdf},
	author = {Koch, Stefan and Schneider Georg}
}
