Sequential Hypothesis Tests for Identifying the Minimum Dose with a Threshold Effect

We propose a procedure to identify a lowest dose having greater effect than a threshold dose under the assumption of monotonicity of dose mean response in dose response test. So, we use statistics based on contrasts among sample means and apply a group sequential procedure to our procedure to identify effectively the dose. If we can identify the dose at an early step in the sequential test, since we can terminate the procedure with a few observations, the procedure is useful from an economical point of view. In a simulation studies, we compare the superiority among these procedures based on three contrasts.     

Production and changeover control policies of a class of failure prone buffered flow-shops

This article deals with a stochastic optimal control problem for a class of buffered multi-parts flow-shops manufacturing system. The involved machines are subject to random breakdowns and repairs. The flow-shop under consideration is not completely flexible and hence requires setup time and cost in order to switch the production from a part type to another, this changeover is carried on the whole line. Our objective is to find the production plan and the sequence of setups that minimise the cost function, which penalises inventories/backlogs and setups. A continuous dynamic programming formulation of the problem is presented. Then, a numerical scheme is adopted to solve the obtained optimality conditions equations for a two buffered serial machines two parts case. A complete heuristic policy, based on the numerical observations which describe the optimal policies in system states, is developed. It will be shown that the obtained policy is a combination of a KANBAN/CONWIP and a modified hedging corridor policy. Moreover, based on our observations and existent research studies extension to cover more complex flow-shops is henceforth possible. The robustness of such a policy is illustrated through sensitivity analysis.     

Point-symmetry models and decomposition for collapsed square contingency tables

For square contingency tables with ordered categories, there may be some cases that one wants to analyze them by considering collapsed tables with some adjacent categories combined in the original table. This paper proposes three kinds of new models which have the structure of point-symmetry (PS), quasi point-symmetry and marginal point-symmetry for collapsed square tables. This paper also gives a decomposition of the PS model for collapsed square tables. The father's and his daughter's occupational mobility data are analyzed using new models.     

On the maximum number of constraints for s-symbol balanced arrays of strength t

Several upper bounds on the maximum number of constraints for s-symbol balanced arrays of strength t are given. Some bounds derived here include the results obtained by Rafter and Seiden (1974), Chopra (1982, 1983) and Saha, Mukerjee and Kageyama (1983).     

Child Anger Regulation, Parental Responses to Children's Anger Displays, and Early Child Antisocial Behavior

The display and regulation of child anger in family interaction was coded in a sample of 240 boys and girls at child age 6, and coded using the Specific Affect Coding System. Child antisocial behavior was longitudinally assessed, beginning in kindergarten. Pooled‐ and family‐level analyses were used to assess hazard rates for child anger. Parents’ ability to modulate their own emotions and negative behavior, and children's ability to down‐regulate anger were associated with increased latency for child anger. Hazard for child anger increased as parents’ insensitive and negative responses toward the child cumulated during family interaction. Macro‐level, non‐hazard analyses indicated that chronic levels of child antisocial behavior were associated with the frequency of parental negative behavior, but not with the frequency of child anger. Micro‐level hazard analyses indicated that children's ability to regulate anger was related to chronic levels of child covert but not overt antisocial behavior.     

Optimization problems for consecutive-2-out-of-n:G system

Abstract

This paper considers the optimization problems for a consecutive-2-out-of-n:G system where n is considered to be fixed or random. When the number of components is constant, the optimal number of components and the optimal replacement time are discussed by minimizing the expected cost rates. Furthermore, we focus on the above discussions again when n is a random variable. We give an approximate value of MTTF and propose the preventive replacement policy, respectively.     

Statistical Analysis of Marginal Count Failure Data

Manufacturers want to assess the quality andreliability of their products. Specifically, they want to knowthe exact number of failures from the sales transacted duringa particular month. Information available today is sometimesincomplete as many companies analyze their failure data simplycomparing sales for a total month from a particular departmentwith the total number of claims registered for that given month.This information—called marginal count data—is, thus,incomplete as it does not give the exact number of failures ofthe specific products that were sold in a particular month. Inthis paper we discuss nonparametric estimation of the mean numbersof failures for repairable products and the failure probabilitiesfor nonrepairable products. We present a nonhomogeneous Poissonprocess model for repairable products and a multinomial modeland its Poisson approximation for nonrepairable products. A numericalexample is given and a simulation is carried out to evaluatethe proposed methods of estimating failure probabilities undera number of possible situations.     

Moment estimators for the beta-binomial distribution

A new moment estimator of the dispersion parameter of the beta-binomial distribution is proposed. It is derived by the method of moments which is constrained to satisfy the unbiasedness of the estimating equation. It gives a better performance than those of the usual moment estimators and the stabilized moment estimator proposed by Tamura & Young. The bias of the estimator is smaller than that of the maximum likelihood estimate in a wide range of parameter space.     

Crime news,fear of crime,and mistrust: an examination of protective factors against influences of local crime news

This study investigates interpersonal communication ties and a neighborhood context as moderators of the influences of local crime news on fear of crime and mistrust. Data from a web survey of residents in Chicago show that the relationship between attention to local crime news and fear of crime is weaker for respondents who more frequently communicate with neighbors both intimately and casually and who live in more walkable neighborhoods. Data also indicate that the relationship between local crime news and mistrust is weaker for those who more often communicate with neighbors intimately and live in more walkable neighborhoods. Findings are discussed in terms of protective factors against the negative influences of local crime news.     

Technological progress, income inequality, and fertility

This paper constructs an overlapping-generations model with two different types of technology: modern, which can be accessed only by the skilled, and traditional, which can be accessed by the unskilled. The model described in this paper shows that a rise in the wage premium for skilled workers caused by skill-biased technological changes explains the following key stylized facts: with economic development, the fraction of skilled people increases, the fertility rate declines, and income inequality rises and then falls. The model also explains the observed gradual rises in income inequality in developed countries.