Nonparametrio bayes and empirical bayes estimation of the residual survival function at age t

Nonparametric Bayes and empirical Bayes estimations of the

survival function of a unit of age t (> 0) using Dirichlet

process prior are presented. The proposed empirical Bayes

estimators are found to be “asymptotically optimal” in the sense of Robbins (1955). The performances of the proposed

empirical Bayes estimators are compared with those of certain

rival estimators in terms of relative savings loss, The exact

expressions for Bayes risks are also provided in certain cases.     

Minimum variance unbiased estimation in natural exponential families generated by stable distributions

The class of nature exponential families generated by stable distributions has been introduced in different contexts by several authors. Tweedie (1984) and Jorgensen (1987) studied this class in the context of generalized liner models and exponential dispersion models. Bar-Lev and Enis (1986) introduced this class in the context of the property of reproducibility in natural exponential families and Hougaard (1986) found the distributions in this class to be natural candidates for applications as survival distributions in life tables for heterogeneous populations. In this note, we consider such a class in the context of minimum variance unbiased estimation. For each family in this class, we obtain an explicit expression for the uniformly minimum variance unbiased estimator for the r-th cumlant, the density function, and the reliability function.     

On dual power assignment optimization for biconnectivity

Topology control is an important technology of wireless ad hoc networks to achieve energy efficiency and fault tolerance. In this paper, we study the dual power assignment problem for 2-edge connectivity and 2-vertex connectivity in the symmetric graphical model which is a combinatorial optimization problem from topology control technology.The problem is arisen from the following origin. In a wireless ad hoc network where each node can switch its transmission power between high-level and low-level, how can we establish a fault-tolerantly connected network topology in the most energy-efficient way? Specifically, the objective is to minimize the number of nodes assigned with high power and yet achieve 2-edge connectivity or 2-vertex connectivity.We addressed these optimization problems (2-edge connectivity and 2-vertex connectivity version) under the general graph model in (Wang et al. in Theor. Comput. Sci., 2008). In this paper, we propose a novel approximation algorithm, called Candidate Set Filtering algorithm, to compute nearly-optimal solutions. Specifically, our algorithm can achieve 3.67-approximation ratio for both 2-edge connectivity and 2-vertex connectivity, which improves the existing 4-approximation algorithms for these two cases.     

The Motivational Interpretation of Institutions

Lorsqu'on distingue la motivation de rle de la motivation personnelle sentie, les institutions humaines peuvent ětre analysées sans que l'analyse soit liée a une explication psychologique ou structurelle. La position de ≪ l'individualisme méthodologique ≫ si souvent préconisée par Homans embrouille, à notre point de vue, I'étude des institutions. Pour autant le sociologisme n'est pas un choix forcé. Les relations entre la structure et le sentiment sont seulement brouillées lorsqu'on identifie ≪ structure ≫ et ≪ autorité≫ et lorsqu'on considère que la charge émotive est synonyme de conduite non-structurée. Dans les deux cas, la coloration motivationnelle d'une relation de rôle est une partie du modèle particulier de l'institution.
When role motivation is distinguished from sentient and personal motivation, human institutions are subject to a kind of analysis which is bound neither to psychological nor structural explanation. The position of "methodological individualism," which Homans has argued at length, can be shown to confuse the study of institutions. But sociologism is not for that reason a forced choice. The relations of structure and sentiment are only confused where "authority" is identified with "structure" and positive effect considered to be unstructured behaviour. The motivational colouration of a role-relationship in either case is part of the given pattern of the institution.     

Analysis of ordered covariate effects among groups with repeated measurements

Testing procedures for ordered covariate effects are developed in the repeated measures experiment. The maximum likelihood estimators of covariate effects under the ordered hypothesis are approximated by the isotonic regression of their unconstrained estimators. The asymptotic null distributions of the test statistics are chi-bar-square distributions which are mixtures of chi-square distributions. A Monte-Carlo simulation reveals that the proposed test for ordered covariate effects is seriously more powerful than the usual chi-square test that neglects the information on the order restriction. These testing methods are applied for analyzing the effect of vitamin E diet supplement on growth rate of animals.     

Job stress,daily stress,and depressive symptoms among low-wage workers in Korea: the role of resilience

This study examined the effects of job stress and daily stress on depressive symptoms and the role of resilience as a moderator among low-wage workers in South Korea. Using purposive sampling, we analysed 254 low-wage workers of private-sector organisations in Seoul and Gyeong-gi province. Results indicated that age, self-rated health, job stress, and daily stress were significant predictors of depressive symptoms, and the moderating effect of resilience was significant only for the relationship between daily stress and depressive symptoms. Findings suggest the significance of using different approaches to manage job stress and daily stress, which in turn will affect low-wage workers’ mental health.     

Variable Selection for Naive Bayes Semisupervised Learning

This article deals with a semisupervised learning based on naive Bayes assumption. A univariate Gaussian mixture density is used for continuous input variables whereas a histogram type density is adopted for discrete input variables. The EM algorithm is used for the computation of maximum likelihood estimators of parameters in the model when we fix the number of mixing components for each continuous input variable. We carry out a model selection for choosing a parsimonious model among various fitted models based on an information criterion. A common density method is proposed for the selection of significant input variables. Simulated and real datasets are used to illustrate the performance of the proposed method.     

A parametric approach for measuring the effect of the 10th revision of the international classification of diseases

Summary.  The World Health Organization revises the international classification of diseases about every 10 years to stay abreast of advances in medical science and to compare international health statistics. However, the new revision (i.e. the 10th revision) introduces discontinuities in mortality trends, making it impossible to compare the mortality statistics before and after the revision directly. The US National Center for Health Statistics published comparability ratios to correct the discontinuities between the two sets of mortality data: one coded by the ninth revision and the other by the 10th revision. We propose a parametric two-stage model to produce new comparability ratios and use these ratios to correct the discontinuities. The asymptotic behaviour of the comparability ratios is investigated. Our model not only measures the extent of discontinuities in trends in mortality but also can be used to forecast future mortality. Comparing with the National Center for Health Statistics's ratios, our comparability ratios smooth out the discontinuities better for most causes.     

Estimating the immigration multiplier: an analysis of recent Korean and Filipino immigration to the United States

"This article explores the effect of 'chaining' through the petitioning of relatives on the demand for future immigrant visas [to the United States]. The data for the study come from a 1986 survey of 3,911 respondents from the Philippines and the Republic of Korea who were interviewed in Manila and Seoul just after they had received their U.S. immigrant visas. Analyses are conducted to derive different types of multipliers that may be used in estimating the effects of chain migration.... The empirical results for the Philippines and Korea indicate that the potential for future immigration through the family reunification entitlements of the immigration law is lower than has previously been suggested." This is a revised version of a paper originally presented at the 1987 Annual Meeting of the Population Association of America (see Population Index, Vol. 53, No. 3, Fall 1987, p. 385).