Empirical studies of open source evolution

Copyright @ 2008 Springer-VerlagThis chapter presents a sample of empirical studies of Open Source Software (OSS) evolution. According to these studies, the classical results from the studies of proprietary software evoltion, such as Lehman’s laws of software evolution, might need to be revised, if not fully, at least in part, to account for the OSS observations. The book chapter also summarises what appears to be the empirical status of each of Lehman’s laws with respect to OSS and highlights the threads to validity that frequently emerge in these empirical studies. The chapter also discusses related topics for further research

Assault Weapons Revisited: Policy Options for Regulating Rifles, Shotguns, and Other Firearms 20 Years After the Passage of the Assault Weapons Ban

20 years after President Bill Clinton signed the federal assault weapons ban into law in September 1994 and a decade after Congress allowed that law to lapse -- the question of whether and how to regulate particularly lethal firearms is no longer the primary focus of the national gun debate. In the wake of the December 2012 massacre at Sandy Hook Elementary School in Newtown, Connecticut, President Barack Obama, congressional leaders, and gun-violence prevention advocates alike made deterring dangerous people from accessing guns the top legislative priority with a proposal for comprehensive background checks for all gun sales. This shift in focus to prevent dangerous people from accessing guns is appropriate: A broad set of research suggests that such measures are effective in reducing gun violence. Additionally, there is overwhelming support in opinion polls for expanding background checks and similar measures aimed at restricting dangerous people from accessing guns. But the debate persists about whether and how to best regulate assault rifles and other types of firearms that may pose heightened risks to public safety. For more than 20 years, there has generally been only one policy solution offered in this debate: a ban on assault weapons.This report considers how gun laws have evolved to address different classes of firearms and looks more broadly at how federal and state laws treat rifles and shotguns differently than handguns and whether all of those distinctions continue to make sense. It also examines data on the changing nature of gun violence and the increasing use of long guns and assault rifles by criminals, with a focus on Pennsylvania as a case study

Variability and Evolution in Systems of Systems

In this position paper (1) we discuss two particular aspects of Systems of Systems, i.e., variability and evolution. (2) We argue that concepts from Product Line Engineering and Software Evolution are relevant to Systems of Systems Engineering. (3) Conversely, concepts from Systems of Systems Engineering can be helpful in Product Line Engineering and Software Evolution. Hence, we argue that an exchange of concepts between the disciplines would be beneficial.Comment: In Proceedings AiSoS 2013, arXiv:1311.319

Agent-based simulation of open source evolution

We present an agent-based simulation model developed to study how size, complexity and effort relate to each other in the development of open source software (OSS). In the model, many developer agents generate, extend, and re-factor code modules independently and in parallel. This accords with empirical observations of OSS development. To our knowledge, this is the first model of OSS evolution that includes the complexity of software modules as a limiting factor in productivity, the fitness of the software to its requirements, and the motivation of developers. Validation of the model was done by comparing the simulated results against four measures of software evolution (system size, proportion of highly complex modules, level of complexity control work, and distribution of changes) for four large OSS systems. The simulated results resembled the observed data, except for system size: three of the OSS systems showed alternating patterns of super-linear and sub-linear growth, while the simulations produced only super-linear growth. However, the fidelity of the model for the other measures suggests that developer motivation and the limiting effect of complexity on productivity have a significant effect on the development of OSS systems and should be considered in any model of OSS development

System Evolution, Feedback and Compliant Architectures

Proceedings, International Workshop on Feedback and Evolution in Software and Business Processes (FEAST 2000), Imperial College, London. Supported by EPSRCPostprintNon peer reviewe

Intellectual Property and the Prisoner’s Dilemma: A Game Theory Justification of Copyrights, Patents, and Trade Secrets

In this article, I will offer an argument for the protection of intellectual property based on individual self-interest and prudence. In large part, this argument will parallel considerations that arise in a prisoner’s dilemma game. In brief, allowing content to be unprotected in terms of free access leads to a sub-optimal outcome where creation and innovation are suppressed. Adopting the institutions of copyright, patent, and trade secret is one way to avoid these sub-optimal results

Iterative criteria-based approach to engineering the requirements of software development methodologies

Software engineering endeavours are typically based on and governed by the requirements of the target software; requirements identification is therefore an integral part of software development methodologies. Similarly, engineering a software development methodology (SDM) involves the identification of the requirements of the target methodology. Methodology engineering approaches pay special attention to this issue; however, they make little use of existing methodologies as sources of insight into methodology requirements. The authors propose an iterative method for eliciting and specifying the requirements of a SDM using existing methodologies as supplementary resources. The method is performed as the analysis phase of a methodology engineering process aimed at the ultimate design and implementation of a target methodology. An initial set of requirements is first identified through analysing the characteristics of the development situation at hand and/or via delineating the general features desirable in the target methodology. These initial requirements are used as evaluation criteria; refined through iterative application to a select set of relevant methodologies. The finalised criteria highlight the qualities that the target methodology is expected to possess, and are therefore used as a basis for de. ning the final set of requirements. In an example, the authors demonstrate how the proposed elicitation process can be used for identifying the requirements of a general object-oriented SDM. Owing to its basis in knowledge gained from existing methodologies and practices, the proposed method can help methodology engineers produce a set of requirements that is not only more complete in span, but also more concrete and rigorous