A General Approach To Nonparametric Histogram Estimation

We note that some classical functional estimation problems may be reduced to a general unique framework and study an estimator within this general framework that reduces to the classical histogram type estimators in various examples presented. The convergence in probability and the almost complete convergence of this general estimator are studied obtaining convergence conditions which reduce to the classical conditions in each case. Finally, this general framework provides conditions for the convergence of the finite dimensional distributions of the associated empirical process.     

Skuka and the Absurd in Gogol'’s Tale of the ‘Two Ivans’

The present article is devoted to an analysis of Gogol'’s last story from his Ukrainian cycle, “The Story of How Ivan Ivanovich Quarrelled with Ivan Nikiforovich”; it makes use of canonical as well as innovative approaches to Gogol'’s tale in order to explore the significance of the epilogue to an interpretation of the story as a whole. The examination will encompass ideas on the temporal aspects of the narration, the philosophical concept of ennui/skuka, and the possible significance of the camera obscura as the setting for one of the key moments in the story. Whereas the camera obscura is the setting of the quarrel between the two main characters, the story ends with a manifestation of skuka from the narrator: how do these two elements relate to each other, and what do they suggest in terms of the possibility of reaching an all-encompassing interpretation of the ‘Two Ivans’?     

Vygotsky’s Anomalous Spinozism

Abstract

This article exposes sources and influences of Spinoza in some of Vygotsky’s works, keeping in mind its meaning for the creation of a “new man” in Soviet Socialism. We try to understand the features of Vygotsky´s reading of Spinoza in an active dialogue with contemporary studies of 17th-century philosophy and its consequences for a materialist psychology. In this direction, we discuss references to Spinoza done by Vygotsky in the context of the latter’s argumentative style as well as studies of Engels, Plekhanov and Deborin as possible sources in Vygotsky´s approach to Spinoza. Paraphrasing Negri´s take on Spinoza as the “wild anomaly” of the 17th-century, we argue that Vygotsky performed an anomalous reading of Spinoza. In spite of the similarities with Deborin´s view of the modern philosopher, Vygotsky had plans that were more ambitious for Spinozist materialism and determinism. We trace the anomalous way in that the latter´s materialism reveals itself as one of randomness and contingency, against a rigidly structured projection of state, society, or model of human beings. We cannot figure out exactly which “model of man“ Vygotsky had in mind in his take on Spinoza, but we are able to recognize some core aspects in his reasoning. Roughly, these include the unity between mind and body, which can take the most diverse forms in the common body of multitude; the bases of consciousness in the affection; the integration, in the psychological systems, of affect, will, and desire; and the Spinozan ethics as a reference to life.     

Bayesian inference for power law processes with applications in repairable systems

Statistical models for recurrent events are of great interest in repairable systems reliability and maintenance. The adopted model under minimal repair maintenance is frequently a nonhomogeneous Poisson process with the power law process (PLP) intensity function. Although inference for the PLP is generally based on maximum likelihood theory, some advantages of the Bayesian approach have been reported in the literature. In this paper it is proposed that the PLP intensity be reparametrized in terms of (β,η), where β is the elasticity of the mean number of events with respect to time and η is the mean number of events for the period in which the system was actually observed. It is shown that β and η are orthogonal and that the likelihood becomes proportional to a product of gamma densities. Therefore, the family of natural conjugate priors is also a product of gammas. The idea is extended to the case that several realizations of the same PLP are observed along overlapping periods of time. Some Monte Carlo simulations are provided to study the frequentist behavior of the Bayesian estimates and to compare them with the maximum likelihood estimates. The results are applied to a real problem concerning the determination of the optimal periodicity of preventive maintenance for a set of power transformers. Prior distributions are elicited for β and η based on their operational interpretation and engineering expertise.     

Generalized Tobit models: diagnostics and application in econometrics

The standard Tobit model is constructed under the assumption of a normal distribution and has been widely applied in econometrics. Atypical/extreme data have a harmful effect on the maximum likelihood estimates of the standard Tobit model parameters. Then, we need to count with diagnostic tools to evaluate the effect of extreme data. If they are detected, we must have available a Tobit model that is robust to this type of data. The family of elliptically contoured distributions has the Laplace, logistic, normal and Student-t cases as some of its members. This family has been largely used for providing generalizations of models based on the normal distribution, with excellent practical results. In particular, because the Student-t distribution has an additional parameter, we can adjust the kurtosis of the data, providing robust estimates against extreme data. We propose a methodology based on a generalization of the standard Tobit model with errors following elliptical distributions. Diagnostics in the Tobit model with elliptical errors are developed. We derive residuals and global/local influence methods considering several perturbation schemes. This is important because different diagnostic methods can detect different atypical data. We implement the proposed methodology in an R package. We illustrate the methodology with real-world econometrical data by using the R package, which shows its potential applications. The Tobit model based on the Student-t distribution with a small quantity of degrees of freedom displays an excellent performance reducing the influence of extreme cases in the maximum likelihood estimates in the application presented. It provides new empirical evidence on the capabilities of the Student-t distribution for accommodation of atypical data.     

Adoption of technology by the low-income population segment: The low-cost hot water heater case

The employment of means for efficient use of water and energy are being increasingly incentivized, in relation to the sustainability of buildings. In Brazil, there is much concern regarding the difficulty of getting low-income segments of the population to adopt energy-saving technologies. This study provides guidelines for the inclusion of manufactured, low-cost solar water heaters (LCSWH) in low-income housing in combination with environmental education of this segment of the population. Therefore, a group of dwellings located in a low-income community in Campinas SP, Brazil, was selected for installation of LCSWHs, which were assembled and installed by the study population itself, who also participated in environmental awareness workshops. Particularly apparent in the results obtained, was a tendency to reduce energy consumption by using the LCSWH, attributable in part to behavioral changes from environmental awareness; and that the planning, application or organized systematization of knowledge is feasible in low-income housing, provided it is not promoted solely by dependency culture, since the objective is to provide an instrument for self-discovery, mobilization and participation by the population.     

A bus stop shelter evaluated from the user's perspective

This study aims to evaluate the current bus stop shelter model used in Florianópolis, Brazil, through a functional analysis--focused in the relationship between the shelter, the users and their activities--and also to analyse users' perceptions. The methodology consisted of exploratory visits, anthropometric analysis, observation and interviews. The exploratory visit intended to survey the physical characteristics of the shelter (dimensions, materials, colors, displayed information) and its position on the sidewalk. The anthropometric analysis was made to verify whether the dimensions of the shelters were adequate to users' needs. The observation provided data for the analysis of users' behavior, which involved a biomechanical study of their postures, an ownership/occupancy analysis in terms of territoriality and studies about spatial requirements of interpersonal relations (proxemics). The interviews helped to analyze how the user perceives the quality of some of the main functions of the shelter: to provide physical and psychological comfort and to display information about the public transportation system. As a result, the overall conclusion is that shelters do not meet users' needs. Recommendations are provided in order to improve physical and psychological comfort and to display relevant information about the transportation system.