Preventive replacement policies with products update announcements

Abstract

When we consider the improvement of the functional performances that are released by the new updates of the products, it is an interesting problem to revisit the existing replacement policies. For such a viewpoint, four replacement models with product update announcements, i.e., PUA for abbreviation, are given in this paper: Model 1, the unit is replaced at time T or at PUA over time T. Model 2, the unit is replaced at the Kth failure or at PUA over the Kth failure. By considering both time T and failure K, Models 3 and 4 are obtained based on the approaches of replacement first and last. We obtain the expected cost rates for four models and discuss analytically their optimal replacement policies Further, numerical examples are given when the time for PUA has an exponential distribution.     

Have Japanese People Become Asexual? Love in Japan

This article examines changing romantic relationships in contemporary Japanese society. It specifically investigates whether Japanese people in their twenties and thirties have become asexual; that is, whether they tend to have few sexual experiences or interests. Data were collected through an internet survey; this article uses a subsample of 9,940 respondents. The dependent variables were the number of lovers respondents had during and after junior high school; the independent variable was the respondents’ age. Regression analyses found a clear trend toward asexual behavior among young men (in their twenties and thirties). However, young women are not as asexual as the previous generation. This asexualization of men may have contributed to Japan’s sharply declining marriage and birth rates. If so, other Asian societies may learn lessons from Japan’s experiences in the future.     

Production seat booking system for the combination of make-to-order and make-to-stock products

This study deals with the problem of the production seat booking system. Like an airline or train booking system, customers' orders are assigned a production seat. Using the production seat booking system, inquiries about the delivery for individual orders can be answered quickly. The key issues in the production seat booking system are: (1) In which manufacturing environments are the production seat booking system appropriate and efficient? (2) How should the production seat be set? (3) How should orders be assigned a production seat? A production planning model is formulated for a production seat booking system with a combination of make-to-order and maketo-stock as production environment. Two kinds of variables are set as policy in the model: one is a variable for setting production capacity and the other a variable for assigning orders a production seat. By focusing on the characteristics of market demand, this paper clarifies the following points: (1) How do these policy variables affect the manufactuiring performance? (2) How does the buffer inventory for make-to-stock product affect the degree of the delivery date satisfaction for make-toorder products? (3) Within what range should the two policy variables be set in order to maintain the unfilled-rate of maketo-stock product under the specified level and the degree of delivery date satisfaction for make-to-order products over the specified level? This paper presents a basis for designing for a production seat booking system through a series of numerical experiments.     

Efficient Regularization Parameter Selection Via Information Criteria

In a nonlinear regression model based on a regularization method, selection of appropriate regularization parameters is crucial. Information criteria such as generalized information criterion (GIC) and generalized Bayesian information criterion (GBIC) are useful for selecting the optimal regularization parameters. However, the optimal parameter is often determined by calculating information criterion for all candidate regularization parameters, and so the computational cost is high. One simple method by which to accomplish this is to regard GIC or GBIC as a function of the regularization parameters and to find a value minimizing GIC or GBIC. However, it is unclear how to solve the optimization problem. In the present article, we propose an efficient Newton–Raphson type iterative method for selecting optimal regularization parameters with respect to GIC or GBIC in a nonlinear regression model based on basis expansions. This method reduces the computational time remarkably compared to the grid search and can select more suitable regularization parameters. The effectiveness of the method is illustrated through real data examples.     

Euler characteristic heuristic for approximating the distribution of the largest eigenvalue of an orthogonally invariant random matrix

The Euler characteristic heuristic has been proposed as a method for approximating the upper tail probability of the maximum of a random field with smooth sample path. When the random field is Gaussian, this method is proved to be valid in the sense that the relative approximation error is exponentially smaller. However, very little is known about the validity of the method when the random field is non-Gaussian. In this paper, as a milestone to developing the general theory about the validity of the Euler characteristic heuristic, we examine the Euler characteristic heuristic for approximating the distribution of the largest eigenvalue of an orthogonally invariant non-Gaussian random matrix. In this particular example, if the probability density function of the random matrix converges to zero sufficiently fast at the boundary of its support, the approximation error of the Euler characteristic heuristic is proved to be small and the approximation is valid. Moreover, for several standard orthogonally invariant random matrices, the approximation formula for the distribution of the largest eigenvalue and its asymptotic error are obtained explicitly. Our formulas are practical enough for the purpose of numerical calculations.     

Teaching Note—Asserting Social Work’s Role in Developing an Interprofessional Education Project

ABSTRACT

Interprofessional (IP) education is an essential component of today’s health care education. IP education has been recognized and supported for its potential to educate workforce-ready health care clinicians with the knowledge and skills, necessary to collaboratively deliver high-quality, client-centered care. While social work’s reflective, patient-centered, and holistic approach to care is invaluable in addressing healthcare challenges at all levels, social work’s lack of involvement in IP health care team practice is evident in the development of IP education curriculum with other health care disciplines. This article describes how one School of Social Work at a regional public university became part of a longitudinal IP education project in collaboration with a large R-1 research university, creating an IP opportunity for Master’s in Social Work (MSW) students. It also discusses the process taken for social work inclusion in the IP project, an experiential elective course designed to supplement the project, as well as Transformative Learning Theory, the conceptual framework used.     

A model of the species rank-abundance relation for a community in an open habitat

Summary A mathematical model is proposed to describe the relationship between the abundance and the rank of species in order from the most abundant to the least in a community in an open habitat. This model is derived as a corollary of a species-area equation (Kobayashi, 1975) which could be expected in the case where the individuals of each species are uniformly distributed over a habitat area. Numerical simulation reveals that a rank-abundance curve for a universe results in different species-area or species-individual curves according to the spatial distribution of individuals, and that the relative abundance of each species in a sample varies with sample size unless the spatial distribution of individuals is uniform. A species-individual curve obtained bySanders’s (1968) rarefaction method agrees with that observed actually only for the spatially uniform distribution. Change in the pattern of rank-abundance curve with species diversity and with sample size is discussed in relation to the present model.     

日本横滨大同学校之创立

日本横滨大同学校是康有为、梁启超等维新派和孙中山、陈少白等革命派共同创办的华侨子弟教育机构。以前的研究由于资料不足和革命派与维新派的记载互有出入，所以关于大同学校的创办日期众说纷纭，正确的说法应该是分别从“创立”、“开校”两个不同层面来判断。日本大同学校的创立不仅反映了革命派与维新派的不同教育价值观，也折射出清末政治的潮起潮落。     

Renationalisation of space in everyday life in Singapore

As globalisation becomes more and more familiar in our everyday lives, one readily visible phenomenon is the increasing number of migrants from outside the borders of nation states. This influx of migrants inevitably makes societies more complicated racially and culturally, and a ‘multi-racial’ or ‘multi-cultural’ society is no longer the monopoly of migrant societies such as the United States or Australia. This spread of multi-racial and multi-cultural societies in the world, however, does not mean that we have achieved racial and cultural co-existence (among nationals, and needless to say between host society and migrants) without hierarchies. In the face of a constant flow of migrants, both the host states and host societies need to control migrants, to ensure that migrants will co-exist with the host society as the host society wishes. Hierarchy and difference need to be created and maintained by the host society to control the influx of migrants in their everyday life. This paper explores how Singapore society draws a border between itself and female migrant domestic workers. For this purpose, it examines both everyday discourses of Singaporean employers about female migrant domestic workers and the efforts of the Singapore Muslim Converts’ Association to teach such workers to become ‘good Muslims'.     

How to Get a Longer Job? Roles of Human and Social Capital in the Japanese Labor Market

This article investigates the roles of human and social capital played in the Japanese labor market. Our research question is whether they interact to accelerate or decelerate each other to provide first jobs of a long duration. Based on the literature, we focus on the bonding functions of friends and relatives. Using the 2005 Social Stratification and Social Mobility Survey Data, we measure human capital by educational attainment (college education) and social capital by job search methods (using friends or relatives). The dependent variable is the hazard rate of turnover from the first job. We find that social capital especially benefits those with low human capital (high school graduates). When friends or relatives introduce workers to jobs, high school graduates tended to stay longer in their first jobs and had a lower turnover than college graduates did. This means that social capital decelerated effects of human capital. Therefore, in the Japanese labor market, social capital plays a complementary role in mitigating educational disadvantage.