Bayesian inference for fault based software reliability models given software metrics data

We wish to predict the number of faults N and the time to next failure of a piece of software. Software metrics data are used to estimate the prior mean of N via a Poisson regression model. Given failure time data and a some well known fault based models for interfailure times, we show how to sample the relevant posterior distributions via Gibbs sampling using the package Winbugs. Our approach is illustrated with an example

Bayesian inference for a software reliability model using metrics information.

In this paper, we are concerned with predicting the number of faults N and the time to next failure of a piece of software. Information in the form of software metrics data is used to estimate the prior distribution of N via a Poisson regression model. Given failure time data, and a well known model for software failures, we show how to sample the posterior distribution using Gibbs sampling, as implemented in the package "WinBugs". The approach is illustrated with a practical example

Multiple hypothesis testing and clustering with mixtures of non-central t-distributions applied in microarray data analysis

Multiple testing analysis, based on clustering methodologies, is usually applied in Microarray Data Analysis for comparisons between pair of groups. In this paper, we generalize this methodology to deal with multiple comparisons among more than two groups obtained from microarray expressions of genes. Assuming normal data, we define a statistic which depends on sample means and sample variances, distributed as a non-central t-distribution. As we consider multiple comparisons among groups, a mixture of non-central t-distributions is derived. The estimation of the components of mixtures is obtained via a Bayesian approach, and the model is applied in a multiple comparison problem from a microarray experiment obtained from gorilla, bonobo and human cultured fibroblasts.Clustering, MCMC computation, Microarray analysis, Mixture distributions, Multiple hypothesis testing, Non-central t-distribution

Using weibull mixture distributions to model heterogeneous survival data

In this article we use Bayesian methods to fit a Weibull mixture model with an unknown number of components to possibly right censored survival data. This is done using the recently developed, birth-death MCMC algorithm. We also show how to estimate the survivor function and the expected hazard rate from the MCMA output

Variação diurna do cortisol e sua relação com o estresse: otimismo e estratégias de enfrentamento em mulheres com câncer de mama

O ritmo diurno do cortisol vem sendo visto alterado nos pacientes com câncer. Fatores como o avanço da doença e os níveis de estresse estão sendo considerados para explicar essa condição; contudo, os resultados não são claros. O objetivo deste estudo foi avaliar e determinar se existem diferenças nos níveis de cortisol em mulheres com câncer de mama de diferentes estágios, bem como analisar estratégias de enfrentamento. Foram coletadas amostras de cortisol salival durante dois dias e aplicados questionários psicológicos de estresse percebido, otimismo disposicional e estratégias de enfrentamento a 17 mulheres com câncer de mama em estágio I, II e III. Os resultados mostram que as pacientes com esse câncer nos três estágios apresentam um ritmo diurno de cortisol normal e não se diferenciam significativamente na variável de otimismo. A respeito das variáveis psicológicas, só diferem na variável de otimismo. As estratégias de enfrentamento -espírito de luta e evitação cognitiva- são as variáveis que têm mais influência nos níveis de cortisol e explicam 55% da variação. Discutem-se as implicações desses resultados.El ritmo diurno del cortisol se ha visto alterado en los pacientes con cáncer. Factores como el avance de la enfermedad y los niveles de estrés se han considerado para explicar esta condición; sin embargo, los resultados no son claros. El objetivo de este estudio fue evaluar y determinar si existen diferencias en los niveles de cortisol en mujeres con cáncer de mama en diferentes estadios, y analizar la relación entre los niveles de cortisol y el estrés, el optimismo y las estrategias de afrontamiento. Se recolectaron muestras de cortisol salival durante dos días, y se aplicaron cuestionarios psicológicos de estrés percibido (PSS), optimismo disposicional (LOT-R) y estrategias de afrontamiento (MAC) a 17 mujeres con cáncer de mama en estadio I, II y III. Los resultados muestran que las pacientes con cáncer de mama en los tres estadios presentan un ritmo diurno de cortisol normal y no difieren significativamente en los niveles de cortisol. Respecto a las variables psicológicas, solo difieren en la variable de optimismo. Las estrategias de afrontamiento espíritu de lucha y evitación cognitiva son las variables que tienen más influencia en los niveles de cortisol, y explican un 55% de la varianza. Se discuten las implicaciones de estos resultados.Diurnal cortisol rhythm has been altered in patients with cancer. Factors such as disease progression and stress levels are regarded as possible causes to explain this condition, however results are not clear. The aim of this study was to assess and determine whether there are differences in cortisol levels in women with breast cancer in different stages and analyze the relationship between cortisol levels and stress, optimism and coping strategies. Salivary cortisol samples were collected for two days and psychological questionnaires of perceived stress (PSS), dispositional optimism (LOT-R) and coping strategies (MAC) were administered to 17 breast cancer women in stage I, II and III of the disease. The results show that patients with breast cancer in the three stages have a normal diurnal cortisol rhythm and do not differ significantly in cortisol levels. Regarding the psychological variables, they differ only in optimism. Coping strategies such as fighting spirit and cognitive avoidance are the variables that have more influence on cortisol levels, explaining 55% of variance. The implications of these results are discussed

Comparing and calibrating discrepancy measures for Bayesian model selection

Different approaches have been considered in the literatur e for the problem of Bayesian model selection. Recently, a new method was introduced and analys ed in De la Horra (2008) by minimizing the posterior expected discrepancy between the set of data and the Bayesian model, where the chi-square discrepancy was used. In this article, several discrepancy measures are considered and compared by simulation, and it is obtained th at the chi-square discrepancy is reasonable to use. Then, an easy method for calibrating disc repancies is proposed, and the behaviour of this approach is studied on simulated data. Fin ally, a set of real data is analysedPeer Reviewe

Analysis of ESG disclosures in Pillar 3 reports: a text mining approach

La divulgación de información prudencial sobre los riesgos ambientales, sociales y de gobernanza (ASG) será obligatoria, a partir de junio de 2022, para las grandes empresas con valores negociados en un mercado regulado de cualquier Estado miembro. Este artículo trata de evaluar el grado de preparación de las entidades financieras europeas para este requerimiento mediante la aplicación de técnicas de minería de textos para analizar los informes prudenciales, comúnmente denominados informes de Pilar 3, correspondientes al período 2019-2020, de la mayoría de las entidades financieras significativas que están bajo la supervisión directa del BCE, con el fin de evaluar el nivel de concienciación de estas entidades en relación con la materialidad de los riesgos ASG. Al aplicar una sencilla taxonomía de términos basada en léxicos y expresiones regulares, mediante una herramienta que hemos desarrollado, somos capaces de identificar fragmentos relevantes con un alto nivel de precisión, a partir de la búsqueda de diferentes combinaciones de conceptos dentro de la taxonomía de términos. Los resultados indican que, aunque hay un mayor conocimiento de los riesgos ASG y se aprecia un aumento significativo en las instituciones más pequeñas (aquellas con activos por debajo de 30.000 millones de euros), el nivel de detalle incluido es generalmente bajo y la introducción de las nuevas divulgaciones obligatorias ASG debería tener un impacto significativo en el nivel de divulgación de información en esta área.Disclosure of prudential information on environmental, social and governance (ESG) risks will become mandatory from June, 2022 for large institutions with securities traded on a regulated market of any Member State. This paper tries to assess how prepared European financial institutions are for this requirement and applies text mining techniques to analyse the prudential reports, commonly referred to as Pillar 3 reports, for 2019 and 2020 of most of the significant banks under the ECB direct supervision in order to evaluate the level of awareness of these institutions in relation to the materiality of ESG risks. By applying a simple taxonomy of terms based on lexicons and regular expressions using a tool that we have developed, we are able to identify relevant excerpts with a high level of precision searching for different combinations of concepts within the taxonomy of terms. The results indicate that although there is an increased awareness of the ESG risks, with a significant increase in smaller institutions (those with less tan 30 billion in assets), the level of detail included is generally low and the introduction of the new ESG mandatory disclosures should have a significant impact on the level of disclosures in this area

Identidade narrativa e plasticidade cerebral: algumas propostas pedagógicas

Os novos recursos da sociedade da informação, juntamente com os novos conhecimentos sobre o desenvolvimento humano e sobre o funcionamento do cérebro, oferecem uma nova perspectiva sobre os processos de construção da identidade e abrem novas possibilidades ao sujeito no seu processo de autoformação e autodeterminação. A construção narrativa da identidade e a plasticidade neuronal remetem para uma antropologia da complexidade que deve ter em consideração tanto as condições de risco, de incerteza e de racionalidade incompleta através das quais se vai configurando a identidade do sujeito, como as novas possibilidades de realização pessoal que estas representam. Por isso, apresentamos algumas propostas pedagógicas que poderão coadjuvar a realização das promessas da plasticidade e da narratividade.Les nouvelles ressources de la société de l’information et les nouvelles connaissances sur le développement humaine et le fonctionnement du cerveau offrent une nouvelle perspective sur les processus d’autoformation et d’autodétermination du sujet. La construction narrative de l’identité et la plasticité neuronale demandent une anthropologie de la complexité qui doit considérer les conditions de risque, d’incertitude et de rationalité incomplète dans lesquelles l’identité du sujet se configure, aussi que des nouvelles possibilités de réalisation personnelle qu’elles représentent. En suivant ces nouvelles perspectives on présentent quelques proposes pédagogiques qui peut coadjuver la réalisation des promesses de la plasticité et de la narrativité.The information society resources, together with the new knowledge about human development and brain functioning, offer a new overview on identity formation processes. Moreover, they open new possibilities concerning the subject’s autoformation and autodetermination. Narrative identity and neuronal plasticity appeal to anthropology of complexity, which must take into account the risks, uncertainty and incomplete rationality conditions trough which identity is configured, as well as the new possibilities of personal fulfilment they represent. Following this new perspective, we present some pedagogical proposals that we think may contribute to the accomplishment of narrative and plasticity promises

Assessing the data challenges of climate-related disclosures in European banks: a text mining study

El Grupo Intergubernamental de Expertos sobre el Cambio Climático (IPCC) estima que se debe alcanzar el objetivo de cero emisiones netas a escala global para el año 2050. A fin de conseguirlo, muchas empresas privadas se han comprometido a lograr las cero emisiones netas para 2050. El Comité Directivo de Datos Climáticos (CDSC) está trabajando en una iniciativa para crear un repositorio digital central global de divulgaciones climáticas que intente abordar los desafíos de datos actuales. Este documento evalúa el progreso de las instituciones financieras europeas en sus esfuerzos por superar los desafíos de datos descritos por el CDSC. Utilizando un enfoque de minería de textos, junto con la aplicación de modelos de lenguaje de gran tamaño (LLM) para la verificación de contexto, calculamos un Índice de Divulgación de Gases de Efecto Invernadero (GHGDI), analizando 23 divulgaciones muy específicas presentes en los informes ESG comprendidos entre 2019 y 2021 y pertenecientes a la mayoría de los bancos significativos bajo supervisión directa del BCE. Posteriormente se compara este índice con la puntuación otorgada por el Carbon Disclosure Project (CDP). Los resultados indican una correlación moderada entre aquellas instituciones que no informan al CDP cuando se les solicita y un bajo GHGDI. Las instituciones con una puntuación alta, por su parte, no guardan necesariamente correlación con un GHGDI alto.The Intergovernmental Panel on Climate Change (IPCC) estimates that global net-zero should be achieved by 2050. To this end, many private firms are pledging to reach net-zero emissions by 2050. The Climate Data Steering Committee (CDSC) is working on an initiative to create a global central digital repository of climate disclosures, which aims to address the current data challenges. This paper assesses the progress within European financial institutions towards overcoming the data challenges outlined by the CDSC. Using a text-mining approach, coupled with the application of commercial Large Language Models (LLM) for context verification, we calculate a Greenhouse Gas Disclosure Index (GHGDI), by analysing 23 highly granular disclosures in the ESG reports between 2019 and 2021 of most of the significant banks under the ECB’s direct supervision. This index is then compared with the CDP score. The results indicate a moderate correlation between institutions not reporting to CDP upon request and a low GHGDI. Institutions with a high CDP score do not necessarily correlate with a high GHGDI

Documenting Paintings with Gigapixel Photography

[EN] Digital photographic capture of pictorial artworks with gigapixel resolution (around 1000 megapixels or greater) is a novel technique that is beginning to be used by some important international museums as a means of documentation, analysis, and dissemination of their masterpieces. This line of research is extremely interesting, not only for art curators and scholars but also for the general public. The results can be disseminated through online virtual museum displays, offering a detailed interactive visualization. These virtual visualizations allow the viewer to delve into the artwork in such a way that it is possible to zoom in and observe those details, which would be negligible to the naked eye in a real visit. Therefore, this kind of virtual visualization using gigapixel images has become an essential tool to enhance cultural heritage and to make it accessible to everyone. Since today's professional digital cameras provide images of around 40 megapixels, obtaining gigapixel images requires some special capture and editing techniques. This article describes a series of photographic methodologies and equipment, developed by the team of researchers, that have been put into practice to achieve a very high level of detail and chromatic fidelity, in the documentation and dissemination of pictorial artworks. The result of this research work consisted in the gigapixel documentation of several masterpieces of the Museo de Bellas Artes of Valencia, one of the main art galleries in Spain. The results will be disseminated through the Internet, as will be shown with some examples.This research was carried out within the Research Project entitled Captura fotografica de resolucion gigapixel para la documentacion y divulgacion del patrimonio pictorico (01/01/19-01/01/21), reference SP20180066. Project funded with the help of Primeros Proyectos de Investigacion (PAID-06-18), Vicerrectorado de Investigacion,Innovacion y Transferencia de la Universitat Politecnica de Valencia (UPV), Valencia, Spain.Cabezos Bernal, PM.; Rodríguez Navarro, P.; Gil Piqueras, T. (2021). Documenting Paintings with Gigapixel Photography. Journal of imaging. 7(8):1-20. https://doi.org/10.3390/jimaging70801561207