A graphical method for evaluating mixture designs with respect to the slope

Good estimation of the slopes of the mixture response function may be important as well as estimation of mean mixture response. It is possible to evaluate and compare several mixture designs with respect to the slope. A graphical method is proposed that allows us to evaluate a given design's support for the fitted model in terms of slope variance. We can plot variances of slopes along Cox direction or axial direction according to existence of restriction of simplex region or not when comparing several different mixture designs.     

Interaction Effects of the Amount of Practice, Preferred Cane Technique, and Type of Cane Technique Used on Drop-off Detection Performance

This study examined the interaction effects of the amount of practice and the cane technique used in drop-off detection with a sample of 32 adults who were blind. The advantage of the constant contact technique over the two-point touch technique was significantly greater for the less experienced cane users than for the more experienced ones.     

Self-perception of aging and health among older adults in Korea

The way that each individual perceives his or her own aging and health may be a key indicator of adaptation and well-being in old age. This study explored the determinants of self-perception of aging and health using 291 community-dwelling older adults in Korea (mean AGE=69.9). Older individuals with lower levels of education and economic status and various types of health problems (more chronic conditions, greater disability, poorer vision, and greater numbers of sick days) were found to have more negative self-perception of aging and health. In addition, a significant role of psychological factors was observed. For self-perception of health, sense of mastery was found to be a significant factor, and for self-perception of aging, neuroticism was observed to be significant along with sense of mastery. The mediating role of self-perception of health was supported that positive perception of health intervened the adverse effects of health problems on self-perception of aging. The findings demonstrate the important roles of psychological resources and subjective perceptions and suggest a need to consider them when planning interventions.     

Interest rate policies and inflation in interdependent economies: Recent policy dilemmas

This paper examines Federal Reserve Board policies that are premised on a negative short-run association of interest rate movements and the rate of inflation. In particular, econometric evidence is provided, supporting the view that tighter monetary policy appears to raise inflation rates in the short run. Conversely, it is demonstrated that easier monetary policy does not necessarily raise inflation rates in the short run. In the case of uncoordinated monetary restrictiveness, interest rate competition among major countries can produce higher inflation and lower growth than was originally intended.     

Characterizations of the poisson process using,the variance

Let γ(t) be the residual life at time t of the renewal process {A(t), t > 0}, which has F as the common distribution function of the inter-arrival times. In this article we prove that if Var(γ(t)) is constant, then F will be exponentially or geometrically distributed under the assumption F is continuous or discrete respectively. An application and a related example also are given.     

Tests for random time effects and spatial error correlation in panel regression models

We consider a panel model with spatial autocorrelation and heterogeneity across time. Various Lagrange multiplier and likelihood ratio test statistics are developed for testing time effects and spatial effects, jointly, marginally or conditionally. Limiting null distributions of the tests are derived. Size and power performances of the proposed tests are compared by a Monte-Carlo experiment.     

Postretirement work and volunteering by poverty groups informed by role theory

This study uses role theory to examine the association between postretirement work and volunteering among retirees and to determine whether this association varies across poverty status. Data came from the 2012 wave of the Health and Retirement Study (HRS). The sample was restricted to respondents of older retirees (N = 6,619). We found that postretirement work positively influenced volunteering. However, poverty can be a risk factor of volunteering among older retirees. The positive effect of post-retirement work was found to be more significant in the near-poverty group. We provide an empirical foundation to help inform volunteer programs for retirees.     

Types of stressors and bullying perpetration among female adolescents in Korea

ABSTRACT

Research concerning bullying among female adolescents in Korea remains extremely limited. This study examined the impact of three different types of stressors (family stress, friendship stress, and school stress) on bullying perpetration among Korean female adolescents. Five middle schools were randomly selected from 11 schools in Pyeongtaek, Korea. Participants in the study were 374 female students in 7–9th grade. A linear regression analysis based on the different types of stressors was conducted. Findings indicate that family and school related stressors were significantly associated with bullying perpetration. Results supported Bronfenbrenner’s bioecological systems theory. Interventions to decrease family stress and school stress are supported for Korean female adolescents engaged in bullying perpetration.     

Bursts and heavy tails of execution time in business processes

This paper investigates the phenomena and effects of heavy tails of execution time in business processes. We approached the heavy tails as a particular variation of business process execution, and analysed them from empirical data of its execution time. The features and possible causes of the heavy tails were investigated. A workflow simulation was conducted to simulate the heavy tails, in order to evaluate quantitatively their effects to business process performance. The simulation outcomes demonstrate that (1) even a heavy-tailed activity in a business process can cause large variation of end-to-end execution times of the process and (2) there are significant prediction gaps resulted by different assumptions of execution times between an exponential distribution and a heavy-tailed distribution.