Lifetime and survival data are usually the lives of subjects, units, or systems that has been exposed to multiple risks or modes of failure. In the analysis of the data, however, is common to ignore the modes of failure because they are unknown, they are not recorded, or because the complexity of including them in the modeling. It is of interest knowing when the conclusions might be robust to ignoring the failure modes in the analysis. In particular, it would be useful to characterize situations where it could be safely said that the modes of failure effect on the analysis would be negligible or that failing to include such information could completely invalidate the conclusions drawn from the study. As a first step in identifying when the failure modes have little or large influence on the competing risks model, this article studies two different competing risks models: (a) a model with independent risks; (b) a model derived from a multivariate Weibull with dependence.Key words: competing risks, probability plots, log-location-scale family, Weibull distribution, multivariate Weibull with dependence, lognormal distribution. Caracteristicas de dos modelos con riesgos en competencia y riesgos Weibull. ResumenLos datos de tiempos de falla y sobrevivencia se refieren generalmente a la vida de individuos, unidades o sistemas que han sido expuestos a múltiples riesgos o modos de falla. Sin embargo, en el análisis de los datos es común ignorar los modos de falla porque son desconocidos, no se registran o por la complejidad de la modelación al incluirlos. Es importante, por lo tanto, determinar la robustez del análisis ignorando los modos de falla. En particular, sería útil caracterizar situaciones donde pudiera decirse que el efecto de los modos de falla en el análisis es despreciable o donde no incluir tal información pudiera invalidar completamente las inferencias del estudio. Como un primer paso para identificar cuando los modos de falla tienen poca o mucha influencia en el modelo de riesgos en competencia, este artículo estudia dos modelos de riesgos en competencia: (a) un modelo con riesgos independientes; (b) un modelo derivado de una distribución Weibull multivariada con dependencia.Palabras clave: riesgos en competencia, gráficos de probabilidad, familia de log-localización y escala, distribución Weibull, distribución Weibull multivariada con dependencia, distribución lognormal.

In order to contribute to the lack of statistical anomaly detection and sensibility procedures of the response parameters from international seismic codes, this study presents a comparative analysis between multiple Chilean codes for the seismic design of reinforced concrete buildings. The seismic response and its similar implications to the US codes are studied from a model of a reinforced concrete building in the city of Viña del Mar, Chile. The first study case is the NCh433 Of.96 Mod.2009, the second case is the NCh433 Of.96 Mod.2009 + D.S. 117 and 118, and the third case is the NCh433 Of.96 Mod.2009 + D.S. 60 and 61. The results show that the seismic response does not present great differences, but they show noticeable dependencies between multiple parameters within the three study cases. The third case presents the most oversized values of the response parameters, which require a design against a higher base shear. An analysis of the bio-seismic profile is included, which is a procedure commonly used for buildings in Chile, and its indexes are analyzed with statistical models that provide an easy overview of the data structure. Additionally, a pier wall with an opening, and a pier with a T-shaped wall are selected, which present an increase in the amount of reinforcing steel from the first code case to the third, and then to the second code case.

El padre del estilo cognitivo, Hermann Witkin, así llamado por sus aportaciones al desarrollo de una teoría de los estilos cognitivos de campo-dependencia, campo independencia; fue el primero en conceptualizar una diferenciación cognitiva relacionada con desempeños ante tareas que diferentes personas podían resolver con diferentes estrategías. El diseño de sus situaciones de laboratorio ha trascendido a practicas de enseñanza y de aplicaciones diversas. Este artículo presenta el sentido de estas prácticas y su trascendencia.