Assessing the effect of source code characteristics on changeability

Maintenance is the phase of the software lifecycle that comprises any modification after the delivery of an application. Modifications during this phase include correcting faults, improving internal attributes, as well as adapting the application to different environments. As application knowledge and architectural integrity degrade over time, so does the facility with which changes to the application are introduced. Thus, eliminating source code that presents characteristics that hamper maintenance becomes necessary if the application is to evolve. We group these characteristics under the term Source Code Issues. Even though there is support for detecting Source Code Issues, the extent of their harmfulness for maintenance remains unknown. One of the most studied Source Code Issue is cloning. Clones are duplicated code, usually created as programmers copy, paste, and customize existing source code. However, there is no agreement on the harmfulness of clones. This thesis proposes and follows a novel methodology to assess the effect of clones on the changeability of methods. Changeability is the ease with which a source code entity is modified. It is assessed through metrics calculated from the history of changes of the methods. The impact of clones on the changeability of methods is measured by comparing the metrics of methods that contain clones to those that do not. Source code characteristics are then tested to establish whether they are endemic of methods whose changeability decay increase when cloned. In addition to findings on the harmfulness of cloning, this thesis contributes a methodology that can be applied to assess the harmfulness of other Source Code Issues. The contributions of this thesis are twofold. First, the findings answer the question about the harmfulness of clones on changeability by showing that cloned methods are more likely to change, and that some cloned methods have significantly higher changeability decay when cloned. Furthermore, it offers a characterization of such harmful clones. Second, the methodology provides a guide to analyze the effect of Source Code Characteristics in changeability; and therefore, can be adapted for other Source Code Issues

Tracking clones' imprint

Cloning imprint is the lasting effect of cloning on applications. This paper aims to analyze the clone imprint over time, in terms of the extension of cloning, the persistence of clones in methods, and the stability of cloned methods. Such level of detail requires an improvement in the clone tracking algorithms previously proposed, which is also presented. We found that cloned methods are cloned most of their lifetime, cloned methods have a higher density of changes, and that changes in cloned methods tend to be customizations to the clone environment

Evaluating the relation between changeability decay and the characteristics of clones and methods

In this paper we propose a methodology to evaluate if there is a relation between two code characteristics. The methodology is based on relative risk, an epidemiology formula used to analyze the effect of toxic agents in developing diseases. We present a metaphor in which the disease is changeability decay, measured at method level, and the toxic agent is a source code characteristic considered harmful. However, the formula assesses the strength of the relation between any toxic agent and any disease. We apply the methodology to explore cloning as a toxic agent that increases the risk of changeability decay. Cloning is a good agent to analyze given that although there is some evidence of maintainability issues caused by clones, we do not know which clones are harmful, or to what extent. We compare cloning with other possible 'toxic agents', like having high complexity or having high fan-in. We also use the technique to evaluate which clone characteristics (like clone size) may indicate harmful clones, by testing such characteristics as toxic agents. We found that cloning is one of the method characteristics that affects the least changeability decay, and that none of the clone characteristics analyzed are related with changeability decay

Design Principles in Architectural Evolution: a Case Study

We wish to investigate how structural design principles are used in practice, in order to assess the utility and relevance of such principles to the maintenance of large, complex, long-lived, successful systems. In this paper we take Eclipse as the case study and check whether its architecture follows, throughout multiple releases, some principles proposed in the literature

Perdurabilidad empresarial: caso sector administradoras de riesgos profesionales (ARP)

La permanencia de las empresas en el tiempo, de manera exitosa, se constituye en un tema de preocupación para el Gobierno, las empresas y la academia de la Administración. Se han realizado varias investigaciones, materializadas en libros, artículos y ponencias, tratando de explicar por qué unas organizaciones perduran y otras desaparecen. Con el objetivo de hacer un aporte a la academia de la Administración en la identificación de elementos que permitan a las empresas pasar de la longevidad a la perdurabilidad, la Facultad de Administración de la Universidad del Rosario viene desarrollando desde el año 2004 estudios encaminados a tal fin. El grupo de investigación ha establecido lo siguiente: Para socializar los hallazgos encontrados, se ha decidido publicar, a través de los documentos de investigación, algunos casos de empresas y sectores en los cuales la permanencia de algunas de aquellas se ha visto afectada por discontinuidades del entorno. De manera puntual, este documento, realizado de forma conjunta por estudiantes de la asignatura Análisis Estratégico Sectorial aplicado al Sector Salud, impartida en la Maestría en Administración en Salud, y el profesor Hugo Alberto Rivera, pretende hacer un aporte a la línea de investigación, y relacionar las características de la definición del concepto “perdurabilidad”, propuestas por la Facultad de Administración de la Universidad del Rosario y lo encontrado en las empresas. El sector estudiado es el de las Administradoras de Riesgos Profesionales. Se toma la decisión de hacer el estudio, dado que a partir de la vigencia de la Ley 100 de 1993 se reglamentaron, con el Decreto 1295 de 1994, los lineamientos administrativos, económicos y asistenciales referentes a la salud de los trabajadores y a los riesgos profesionales, mediante la creación del Sistema General de Riesgos Profesionales. Este sistema surge a partir del Tercer Libro de la Ley 100 y se rige, al igual que los referentes a pensiones y salud, por los principios de unidad, eficiencia, participación, solidaridad e integralidad. En cuanto al principio de la universalidad, o sea, la garantía de la protección para todas las personas sin ninguna discriminación, el Ministerio de Trabajo y Seguridad Social trabaja para ampliar la cobertura de los trabajadores de los sectores informales, deportivos y campesinos. El sistema cubre a los trabajadores dependientes vinculados mediante contrato de trabajo, los trabajadores independientes, los jubilados incorporados a la fuerza laboral y los estudiantes en práctica que deban ejecutar trabajos que signifiquen fuente de ingreso para la respectiva institución, y cuya actividad formativa es requisito para la culminación de sus estudios. El documento contiene una descripción del sector e incluye un análisis estratégico que permite identificar el estado de las empresas estudiadas y los elementos que pueden contribuir a su perdurabilidad

Clones and Macro-Co-Changes

Ideally, any change that modifies the similar parts of a cloned code snippet should be propagated to all its duplicates. In practice however, consistent propagation of changes in clones does not always happen. Current evidence indicates that clone families have a 50% chance of having consistent changes. This paper measures cloning and co-changes at file level as a proxy to assess the frequency of consistent changes. Given that changes to a clone group are not necessarily propagated in the same commit transaction (i.e., late propagations), our analysis uses macro co-changes instead of the traditional definition of co-changes. Macro changes group bursts of changes that are closer among themselves than to other changes, regardless of author or message. Then, macro co-changes are sets of files that change in the same macro changes. Each cloned file is tagged depending on whether any of the files with which it macro co-changes is cloned with it (during the macro change) or not. Contrary to previous results, we discovered that most of the cloned files macro co-change only with files with which they share clones. Thus providing evidence that macro changes are appropriate to study the conjecture of clones requiring co-changes, and indicating that consistent changes might be the norm in cloned code

Propuesta estratégica de mejora en la implementación de los estándares mínimos del sistema de gestión de la seguridad y salud en el trabajo (SG-SST) en la empresa Prosegur para el primer semestre del 2019.

El documento consiste en un análisis de implementación y propuestas estratégicas sobre las acciones y el plan de mejora del Sistema de Gestión de la Seguridad y la Salud en el Trabajo (SG-SST) en la empresa Prosegur S.A para el primer semestre del 2019.The document consists of an analysis of implementation and strategic proposals on the actions and the improvement plan of the Safety and Health at Work Management System (SG-SST) in the company Prosegur S.A for the first semester of 2019

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Rising rural body-mass index is the main driver of the global obesity epidemic in adults

Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities(.)(1,2) This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity(3-6). Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.Peer reviewe