@proceedings {roblesestimating,
	title = {Estimating Development Effort in Free/Open Source Software Projects by Mining Software Repositories: A Case Study of OpenStack},
	year = {2014},
	month = {05/2014},
	abstract = {Because of the distributed and collaborative nature of free/open source software (FOSS) projects, the development effort invested in a project is usually unknown, even after the software has been released. However, this information is becoming of major interest, especially - but not only- because of the growth in the number of companies for which FOSS has become relevant for their business strategy. In this paper we present a novel approach to estimate effort by considering data from source code management repositories. We apply our model to the OpenStack project, a FOSS
project with more than 1,000 authors, in which several tens of companies cooperate. Based on data from its repositories and together with the input from a survey answered by more than 100 developers, we show that the model offers a simple, but sound way of obtaining software development estimations
with bounded margins of error.},
	keywords = {effort estimation, openstack},
	url = {http://gsyc.urjc.es/~grex/repro/2014-msr-effort/msr14-robles-estimating-effort.pdf},
	attachments = {https://flosshub.org/sites/flosshub.org/files/msr14-robles-estimating-effort.pdf},
	author = {Gregorio Robles and Gonz{\'a}lez-Barahona, Jesus M and Cervig{\'o}n, Carlos and Capiluppi, Andrea}
}
@conference {Robles:2014:EDE:2597073.2597107,
	title = {Estimating Development Effort in Free/Open Source Software Projects by Mining Software Repositories: A Case Study of OpenStack},
	booktitle = {Proceedings of the 11th Working Conference on Mining Software Repositories},
	series = {MSR 2014},
	year = {2014},
	pages = {222{\textendash}231},
	publisher = {ACM},
	organization = {ACM},
	address = {New York, NY, USA},
	abstract = {Because of the distributed and collaborative nature of free / open source software (FOSS) projects, the development effort invested in a project is usually unknown, even after the software has been released. However, this information is becoming of major interest, especially ---but not only--- because of the growth in the number of companies for which FOSS has become relevant for their business strategy. In this paper we present a novel approach to estimate effort by considering data from source code management repositories. We apply our model to the OpenStack project, a FOSS project with more than 1,000 authors, in which several tens of companies cooperate. Based on data from its repositories and together with the input from a survey answered by more than 100 developers, we show that the model offers a simple, but sound way of obtaining software development estimations with bounded margins of error.
},
	keywords = {effort estimation, free software, mining software repositories, open source, openstack},
	isbn = {978-1-4503-2863-0},
	doi = {10.1145/2597073.2597107},
	url = {http://doi.acm.org/10.1145/2597073.2597107},
	attachments = {https://flosshub.org/sites/flosshub.org/files/robles_0.pdf},
	author = {Gregorio Robles and Gonz{\'a}lez-Barahona, Jes{\'u}s M. and Cervig{\'o}n, Carlos and Capiluppi, Andrea and Izquierdo-Cort{\'a}zar, Daniel}
}
@proceedings {1450,
	title = {Exploring the Role of Commercial Stakeholders in Open Source Software Evolution},
	volume = {378},
	year = {2012},
	month = {09/2012},
	pages = {178-200},
	publisher = {IFIP AICT},
	abstract = {It has been lately established that a major success or failure factor of an OSS project is whether or not it involves a commercial company, or more extremely, when a project is managed by a commercial software corporation. As documented recently, the success of the Eclipse project can be largely attributed to IBM{\textquoteright}s project management, since the upper part of the developer hierarchy is dominated by its staff. This paper reports on the study of the evolution of three different Open Source (OSS) projects {\textemdash} the Eclipse and jEdit IDEs and the Moodle e-learning system {\textemdash} looking at whether they have benefited from the contribution of commercial companies. With the involvement of commercial companies, it is found that OSS projects achieve sustained productivity, increasing amounts of output produced and intake of new developers. It is also found that individual and commercial contributions show similar stages: developer intake, learning effect, sustained contributions and, finally, abandonment of the project. This preliminary evidence suggests that a major success factor for OSS is the involvement of a commercial company, or more radically, when project management is in hands of a commercial entity.},
	author = {Capiluppi, Andrea and Stol, Klaas-Jan and Boldyreff, Cornelia}
}
@article {1418,
	title = {Effort estimation of FLOSS projects: a study of the Linux kernel},
	journal = {Empirical Software Engineering},
	year = {2011},
	pages = {1-29},
	abstract = {Empirical research on Free/Libre/Open Source Software (FLOSS) has shown that developers tend to cluster around two main roles: {\textquotedblleft}core{\textquotedblright} contributors differ from {\textquotedblleft}peripheral{\textquotedblright} developers in terms of a larger number of responsibilities and a higher productivity pattern. A further, cross-cutting characterization of developers could be achieved by associating developers with {\textquotedblleft}time slots{\textquotedblright}, and different patterns of activity and effort could be associated to such slots. Such analysis, if replicated, could be used not only to compare different FLOSS communities, and to evaluate their stability and maturity, but also to determine within projects, how the effort is distributed in a given period, and to estimate future needs with respect to key points in the software life-cycle (e.g., major releases). This study analyses the activity patterns within the Linux kernel project, at first focusing on the overall distribution of effort and activity within weeks and days; then, dividing each day into three 8-hour time slots, and focusing on effort and activity around major releases. Such analyses have the objective of evaluating effort, productivity and types of activity globally and around major releases. They enable a comparison of these releases and patterns of effort and activities with traditional software products and processes, and in turn, the identification of company-driven projects (i.e., working mainly during office hours) among FLOSS endeavors. The results of this research show that, overall, the effort within the Linux kernel community is constant (albeit at different levels) throughout the week, signalling the need of updated estimation models, different from those used in traditional 9am{\textendash}5pm, Monday to Friday commercial companies. It also becomes evident that the activity before a release is vastly different from after a release, and that the changes show an increase in code complexity in specific time slots (notably in the late night hours), which will later require additional maintenance efforts.},
	keywords = {complexity, effort estimation, Effort models, mining software repositories, open source software},
	issn = {1573-7616},
	doi = {10.1007/s10664-011-9191-7},
	url = {http://www.springerlink.com/content/612r616k8t52m867/fulltext.html},
	author = {Capiluppi, Andrea and Izquierdo-Cort{\'a}zar, Daniel}
}
@article {1099,
	title = {Evidences in the evolution of OS projects through Changelog Analyses},
	journal = {Proceedings of the 3rd ICSE Workshop on Open Source},
	year = {2003},
	note = {"In this study we concentrate on a very large sample (406 projects) selected randomly from an OS portal[20]" (freshmeat)

"We define three clusters of projects: {\textquoteright}large{\textquoteright} projects as long as they are based on more than 1000KB(40KLOC)..."},
	pages = {19-24},
	abstract = {Most empirical studies about Open Source (OS) projects or products are vertical and usually deal with the flagship, successful projects. There is a substantial lack of horizontal studies to shed light on the whole population of projects, including failures. This paper presents a horizontal study aimed at characterizing OS projects. We analyze a sample of around 400 projects from a popular OS project repository. Each project is characterized by a number of attributes. We analyze these attributes statically and over time. The main results show that few projects are capable of attracting a meaningful community of developers. The majority of projects is made by few (in many cases one) person with a very slow pace of evolution. We then try to observe how many projects count on a substantial number of developers, and analyze those projects more deeply. The goal is to achieve a better insight in the dynamics of open source development. The initial results of this analysis, especially growth in code size and tendency to stability in modularity, seem to be in line with traditional close source development.},
	keywords = {classification, freshmeat, loc, modularity, repository, size, sloc, source code},
	url = {http://hdl.handle.net/10552/1037},
	attachments = {https://flosshub.org/sites/flosshub.org/files/capiluppi2003.pdf},
	author = {Capiluppi, Andrea}
}
