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71.
    
Given a most believed value for a quantity together with upper and lower possible deviations from that value, a rectangular distribution might be used to represent state-of-knowledge about the quantity. If the deviations are themselves known by probability distributions, and the value conditioned on the deviations is rectangular, then the marginal distribution of the value is determined by the distributions of the deviations. Here we show under quite general conditions that conversely, given the marginal distribution, the distributions of the deviations are uniquely determined. The case in which the marginal distribution is trapezoidal is studied in some detail.  相似文献   
72.
    
ABSTRACT

We introduce a new parsimonious bimodal distribution, referred to as the bimodal skew-symmetric Normal (BSSN) distribution, which is potentially effective in capturing bimodality, excess kurtosis, and skewness. Explicit expressions for the moment-generating function, mean, variance, skewness, and excess kurtosis were derived. The shape properties of the proposed distribution were investigated in regard to skewness, kurtosis, and bimodality. Maximum likelihood estimation was considered and an expression for the observed information matrix was provided. Illustrative examples using medical and financial data as well as simulated data from a mixture of normal distributions were worked.  相似文献   
73.
    
Well-known estimation methods such as conditional least squares, quasilikelihood and maximum likelihood (ML) can be unified via a single framework of martingale estimating functions (MEFs). Asymptotic distributions of estimates for ergodic processes use constant norm (e.g. square root of the sample size) for asymptotic normality. For certain non-ergodic-type applications, however, such as explosive autoregression and super-critical branching processes, one needs a random norm in order to get normal limit distributions. In this paper, we are concerned with non-ergodic processes and investigate limit distributions for a broad class of MEFs. Asymptotic optimality (within a certain class of non-ergodic MEFs) of the ML estimate is deduced via establishing a convolution theorem using a random norm. Applications to non-ergodic autoregressive processes, generalized autoregressive conditional heteroscedastic-type processes, and super-critical branching processes are discussed. Asymptotic optimality in terms of the maximum random limiting power regarding large sample tests is briefly discussed.  相似文献   
74.
    
ABSTRACT

Panel datasets have been increasingly used in economics to analyze complex economic phenomena. Panel data is a two-dimensional array that combines cross-sectional and time series data. Through constructing a panel data matrix, the clustering method is applied to panel data analysis. This method solves the heterogeneity question of the dependent variable, which belongs to panel data, before the analysis. Clustering is a widely used statistical tool in determining subsets in a given dataset. In this article, we present that the mixed panel dataset is clustered by agglomerative hierarchical algorithms based on Gower's distance and by k-prototypes. The performance of these algorithms has been studied on panel data with mixed numerical and categorical features. The effectiveness of these algorithms is compared by using cluster accuracy. An experimental analysis is illustrated on a real dataset using Stata and R package software.  相似文献   
75.
    
Abstract

With significant segments of the working population involved in shiftwork, there is the possibility of serious health outcomes. There are two possible pathways to ill health. In the biological pathway the body's circadian rhythms are affected, leading to physiological disturbances and the inability to cope. By contrast, the aim of this study is to elucidate a social pathway by which shiftwork may lead to mental ill health. It examines the mediating influence of work-to-family conflict in the association between shiftwork and depression. Gender differences are also investigated. The sample included 2,931 Canadian respondents with a spouse and at least one child living at home. Close to 28% of respondents were involved in some form of shiftwork. Structural equation modelling supported partial mediation through work-to-family conflict. Further analyses found that mediation was supported in sub-samples of male and female respondents. The results, however, suggest that the experience of shiftwork is quite similar for men and women as no significant differences were found between mediating models. Overall, the findings support the social explanation of the effect of shiftwork on mental health, but they do not rule out other social or biological pathways.  相似文献   
76.
    
ABSTRACT

Current research on return to work (RTW) for employees with common mental disorders suffers from two limitations. First, research mostly focuses on the influence of resources during the absence period ignoring the resources which may facilitate sustainable RTW, i.e. employees continuing to work and thrive at work post-return. Second, research tends to view the work and non-work domains separately and fails to consider the interaction of resources at the individual, group, leader and organisational levels, once back at work. In the present position paper, we present an integrated framework and a preliminary definition of sustainable RTW. Based on current occupational health psychology theory and existing research on RTW, we develop ten propositions for the resources in and outside work, which may promote sustainable RTW. In addition to the individual, group, leader, and organisational levels, we also argue for the importance of the overarching context, i.e. the societal context and the culture and legislation that may promote sustainable RTW. Our framework raises new questions that need to be addressed to enhance our understanding of how key stakeholders can support employees with common mental health disorders staying and thriving at work.  相似文献   
77.
    
ABSTRACT

Illegitimate tasks are tasks that violate norms for what the employee should do as part of the job, and have been found to harm employees’ well-being. The current research uses a mixed methods design to examine the role of attributions on the two types of illegitimate tasks: unreasonable and unnecessary tasks. A sample of 432 engineers described a specific illegitimate task that was assigned to them, the attributions they made and their response. They also completed a quantitative questionnaire. Results from both the qualitative (event level) and quantitative (person level) portions of our study portray differences in the attributions made to unreasonable and unnecessary tasks, as well as differential negative effects on employees’ emotions. In addition, hostile attribution bias was found to moderate the relationship between illegitimate tasks and negative emotions, particularly for unreasonable tasks. This supports the theoretical basis for illegitimate tasks because unreasonable tasks pose a potentially greater risk to the employee’s self-worth than unnecessary tasks that are more often assigned at random.  相似文献   
78.
    
Listeria monocytogenes is a leading cause of hospitalization, fetal loss, and death due to foodborne illnesses in the United States. A quantitative assessment of the relative risk of listeriosis associated with the consumption of 23 selected categories of ready‐to‐eat foods, published by the U.S. Department of Health and Human Services and the U.S. Department of Agriculture in 2003, has been instrumental in identifying the food products and practices that pose the greatest listeriosis risk and has guided the evaluation of potential intervention strategies. Dose‐response models, which quantify the relationship between an exposure dose and the probability of adverse health outcomes, were essential components of the risk assessment. However, because of data gaps and limitations in the available data and modeling approaches, considerable uncertainty existed. Since publication of the risk assessment, new data have become available for modeling L. monocytogenes dose‐response. At the same time, recent advances in the understanding of L. monocytogenes pathophysiology and strain diversity have warranted a critical reevaluation of the published dose‐response models. To discuss strategies for modeling L. monocytogenes dose‐response, the Interagency Risk Assessment Consortium (IRAC) and the Joint Institute for Food Safety and Applied Nutrition (JIFSAN) held a scientific workshop in 2011 (details available at http://foodrisk.org/irac/events/ ). The main findings of the workshop and the most current and relevant data identified during the workshop are summarized and presented in the context of L. monocytogenes dose‐response. This article also discusses new insights on dose‐response modeling for L. monocytogenes and research opportunities to meet future needs.  相似文献   
79.
    

There are production situations where a production facility (e.g. a machine) is used intermittently to produce lot sizes of certain products. Upon completion of production run, the facility may not be available for a random amount of time due to several reasons, such as: the facility needs to be maintained and the maintenance time is random due to unforeseen circumstances; or that the facility is leased by different manufacturers and the demand for the facility is random. As a result of machine unavailability, stock-out situations might arise. This paper extends the work of Abboud et al . (2000, Computers and Operations Research , 27 , 335-351) by assuming learning and forgetting in production. A new mathematical model is developed with numerical examples and sensitivity analysis provided. Furthermore, this paper determines how the overall inventory cost is influenced by the nature of the random variable that represents the unavailability time of the production facility.  相似文献   
80.
This work presents a case study of how a design chain, with more than three tiers of organisations (customer, manufacturer, and supplier), can involve its members in the early stages of the design and development process to meet their needs more effectively. A vertical design chain model, consisting of strategy, process and information levels, is adopted to elucidate how a computer company can provide for different customers and use various suppliers to create synergy within the design chain. The results of this study demonstrate that the re-engineering of cross organisation product design flow, product data management software applications and the integration of information from various parties are critical to the early involvement in a vertical design chain. Based on this case study, the proposed early involvement model can shorten the time taken to develop new products and considerably reduce the number of engineering changes for various manufacturers.  相似文献   
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