Software evolution: the lifetime of fine-grained elements

A model regarding the lifetime of individual source code lines or tokens can estimate maintenance effort, guide preventive maintenance, and, more broadly, identify factors that can improve the efficiency of software development. We present methods and tools that allow tracking of each line’s or token’s birth and death. Through them, we analyze 3.3 billion source code element lifetime events in 89 revision control repositories. Statistical analysis shows that code lines are durable, with a median lifespan of about 2.4 years, and that young lines are more likely to be modified or deleted, following a Weibull distribution with the associated hazard rate decreasing over time. This behavior appears to be independent from specific characteristics of lines or tokens, as we could not determine factors that influence significantly their longevity across projects. The programing language, and developer tenure and experience were not found to be significantly correlated with line or token longevity, while project size and project age showed only a slight correlation.

A Prologue of Git and SVN

Version Control Software or Revision Control Software are the most important things in the world of software development. In this paper, we have described two version control tools: Git and Apache Subversion. Git comes as free and open source code management and version control system which is disseminated with the GNU general public license. Apache Subversion abbreviated as SVN is one amongst a software versioning and revision control systems given as open source under Apache License. Git design, its functionality, and usage of Git and SVN are discussed in this paper. The goal of this research paper is to accentuate on GIT and SVN tools, evaluate and compare five version control tools to ascertain their usage and efficacy.

Early Stage Digital Twins for Early Stage Engineering Design

ABSTRACTWhile extensive modelling - both physical and virtual - is imperative to develop right-first-time products, the parallel use of virtual and physical models gives rise to two interrelated issues: the lack of revision control for physical prototypes; and the need for designers to manually inspect, measure, and interpret modifications to either virtual or physical models, for subsequent update of the other. The Digital Twin paradigm addresses similar problems later in the product life-cycle, and while these digital twins, or the “twinning” process, have shown significant value, there is little work to date on their implementation in the earlier design stages. With large prospective benefits in increased product understanding, performance, and reduced design cycle time and cost, this paper explores the concept of using the Digital Twin in early design, including an introduction to digital twinning, examination of opportunities for and challenges of their implementation, a presentation of the structure of Early Stage Twins, and evaluation via two implementation cases.

Oral health impact on competitive sport practice. Literature review

The high standards of performance required by a professional athlete can only be achieved by a totally healthy individual, so that oral health becomes very important. The aim of this article is to describe the relationship between oral health and sports performance and the role that sports dentistry plays in improving it. Food changes, characterized by high carbohydrate consumption, qualitative and quantitative variations of saliva, as well as the need to improve oral hygiene are all aspects to be considered by professional and amateur athletes. Sports Dentistry is the specialty responsible for the study, revision, control, prevention and treatment of orofacial injuries with their manifestations and related diseases, for maintenance of oral health in the athlete, as well as, the dissemination and information of new knowledge related to oral health and sport, applied in the world of sports competition, both amateur and professional, as the study of non-dental injuries that occur during a dentofacial trauma. In the case of professional teams it is recommended that the oral examination be performed before the beginning of the season, as well as periodic monitoring by the dentist which is important to prevent, the appearance of decay, periodontal disease, trauma and other dental pathologies that may interfere with the health and performance of professional athletes.