The relationships between work characteristics and mental health: examining normal,reversed and reciprocal relationships in a 4-wave study

This longitudinal study examined the causal relationships between job demands, job control and supervisor support on the one hand and mental health on the other. Whereas we assumed that work characteristics affect mental health, we also examined reversed causal relationships (mental health influences work characteristics). Further, the topic of the appropriate time lag for testing causal relationships was addressed. Our hypotheses were tested in a 4-wave study among a heterogeneous sample of 668 Dutch employees using structural equation modelling. The results provide evidence for reciprocal causal relationships between the work characteristics and mental health, although the effects of work characteristics on well-being were causally predominant. The best model fit was found for a 1-year time lag. Compared to earlier—predominantly cross-sectional—results, the present study presents a stronger case for the effects of work characteristics on the development of strain. The results also emphasize the need for a dynamic view of the relationship between work and health; the one-directional viewpoint in many work stress models does not seem to fully capture the relations between work characteristics and well-being.     

An integrated model of supply chain performance evaluation and decision-making using structural equation modelling and fuzzy AHP

This paper aims to propose a comprehensive evaluation tool and decision model, which can help the practitioners to gauge their supply chain performance and guide them in decision-making for further improvements. The model provides a salient notion of integrated supply chain performance evaluation approach distilled from the literature. The five important performance evaluation criteria (supply chain planning performance, supply chain partnership performance, production performance, delivery and logistic performance and customer service and satisfaction performance) and corresponding 19 sub-criteria have been identified. An integrated methodology of structural equation modelling (SEM) and fuzzy analytic hierarchy process (FAHP) have been applied to the proposed model to a real case study of Indian textile–apparel–retail supply chain network.     

基于结构方程模型的政府投资项目代建企业声誉测量实证研究

政府投资项目代建市场正处于发展阶段,所存在的项目管理企业声誉差异较大,为研究声誉机制如何为代建市场带来价值提供了特殊的制度环境。文章确立了包括5个测量因子及19个外显指标的代建企业声誉测量模型,经验证的测量模型更具科学性和可操作性。研究结果显示出组织领导与团队、专业服务质量、工作环境3个因子对声誉的影响力度较大。研究结论旨在将代建企业声誉测量引入代建市场选择机制,从非正式契约层面完善代建企业激励制度设计,实现对代建企业的激励目标,并为其声誉管理提供方向。     

Simultaneous equivariant estimation of the parameters of matrix scale and matrix location-scale models

Eaton and Olkin (1987) discussed the problem of best equivariant estimator of the matrix scale parameter with respect to different scalar loss functions. Edwin Prabakaran and Chandrasekar (1994) developed simultaneous equivariant estimation approach and illustrated the method with examples. The problems considered in this paper are simultaneous equivariant estimation of the parameters of (i) a matrix scale model and (ii) a multivariate location-scale model. By considering matrix loss function (Klebanov, Linnik and Ruhin, 1971) a characterization of matrix minimum risk equivariant (MMRE) estimator of the matrix parameter is obtained in each case. Illustrative examples are provided in which MMRE estimators are obtained with respect to two matrix loss functions.     

泻流分子速度分布的讨论

先导出泻流分子速度分布，然后给出推导理想气体状态方程的一种新的统计方法     

分城乡人口预测中乡-城人口转移技术处理及人口转移预测

针对多区域人口发展方程进行人口预测的乡-城转移人口模式和转移率的处理问题,提出了一个总和乡-城人口转移率的概念与方法,并利用该人口预测方法对我国乡-城转移人口的规模和结构进行预测分析.模拟结果显示,随着人口城镇化水平的提高,2000-2020年内每年的乡-城转移人口为1500万左右,其中将有70%-80%为15-64岁劳动年龄人口,为城镇的发展提供丰富的劳动力资源,同时加剧了农村的人口老龄化.     

Bivariate semi α-Laplace distribution and processes

The Laplace distribution is considered as a better choice for modeling whenever data exhibit high kurtosis and heavier tails than Gaussian tails. Even though this is the case, not much work has been done on bivariate Laplace distribution. In this work, we introduce and study a new class of bivariate distributions called bivariate semi α-Laplace distribution, containing bivariate Laplace distributions. Three characterizations of bivariate semi α-Laplace distribution are obtained. Relation with bivariate semi stable distribution is established. An autoregressive model with bivariate semi α-Laplace marginal distributions is developed.     

轻油部分循环对丙丁烷收率的影响及其应用

油田轻烃回收装置随着原料气气质、气量的变化,丙丁烷的收率普遍偏低。提高丙丁烷的收率成了许多浅冷装置急待解决的问题。轻油部分循环法是方法之一,该方法从脱丁烷塔塔底引一股稳定轻油循环至蒸发器前的管线中,从而对汽液平衡施加影响。本文考虑温度、压力和组成对烃类混合物相平衡的影响,选用SRK真实气体状态方程研究轻油循环掺合比与丙丁烷收率的关系。经计算表明,在温度、压力一定时,只要有轻油循环,丙丁烷的收率就要提高,且随着掺合比的增加而增加,但增幅不尽相同。适宜的掺合比应根据经济分析的结果来确定。在油田气轻烃回收浅冷分离工艺的技术改造中运用轻油部分循环法可有效地提高丙丁烷的收率。     

偶数阶中立型差分方程的线性化振动性

讨论了一类偶数阶线性中立型差分方程所有有界解的振动性,建立了相应的比较定理,得到了线性化振动性的相关结果.     

关于指数Diophantine方程（x^m-1）／（x-1）=y^5

该文证明了：方程（x^m-1）／（x-1）=y^2．x〉1。y〉1，m〉2，没有正整数解（x，y，m）可使m=4（mod5）且m是平方数．