基于斜率判断的灰色周期关联度研究

灰色关联模型从统计序列几何形状的相似程序来判断其紧密程度,传统的灰色关联模型从统计序列的面积、斜率、变化速率等角度来度算其关联程度,这些关联模型受到统计序列横纵坐标(周期和振幅)的双重影响,这在分析统计序列间的单个因素(本文研究仅受周期影响)间的关系时会产生其它因素的干扰。针对这一缺陷,作者根据两条曲线的曲折情况,通过计算各折线的斜率判断曲线的波动周期,提出基于斜率判断的灰色周期关联度。该方法计算简单、判断直观,既可以有效解决上述文献中的问题,又具有传统灰色关联度良好的性质,并通过实例验证该方法的实用性。     

对方案有偏好的区间数多属性灰色关联决策模型

针对属性值以区间数形式给出并且已知方案偏好信息的多属性决策问题,提出了一种灰色关联分析的决策方法。该方法依据一般的灰色关联分析方法的基本思路,给出了该问题的计算步骤,其核心是通过构建并求解一个单目标最优化模型,得到属性权重信息,从而计算出每个方案客观偏好值与主观偏好值的灰色关联系数,进而得到每个方案客观偏好与主观偏好的关联度,根据关联度对所有方案进行排序。最后给出了一个数值例子,结果表明方法简单,有效和易于计算。     

面板数据的灰色矩阵相似关联模型及其应用

根据灰色关联分析的基本思想,在定义了面板数据矩阵表现形式的基础上,以指标为研究对象,从个体和时间两个维度分别衡量了相关因素矩阵与系统特征行为矩阵之间的发展速度指数和增长速度指数的接近程度,并以此作为关联度的度量,将灰色关联分析由传统的向量空间拓展到矩阵空间,提出了面板数据的灰色矩阵相似关联模型,并讨论了其性质。最后以CO₂排放为例,通过测算中部六省2005-2012年碳排放量,建立了中部地区碳排放影响因素的灰色矩阵相似关联模型,实例表明,该模型简单,且具有良好的应用性。     

灰色关联决策方法研究

以灰色决策分析理论为基础,探讨了经典灰色关联决策方法的优势和不足。提出了基于理想方案的最大关联度方法、基于临界方案的最小关联度方法,以及同时考虑理想方案和临界方案的综合关联度方法及其相关概念。建立了灰色区间关联系数公式和灰色区间相对关联系数公式。运用分析技巧,构建了上述3种关联度决策算法。指出了灰色区间关联系数公式和最大关联度方法分别是经典灰色关联系数公式和灰色关联决策方法的推广,而最小关联度方法和综合关联度方法是经典灰色关联决策方法的拓展。文中实例说明了所提出的灰色关联决策方法的合理性及其算法的有效性。     

区域物流需求的灰关联熵分析——以广西北部湾经济区为例

灰关联熵分析法是对传统灰关联分析的一种优化,可以对影响区域物流需求的若干因素进行更为合理的排序.本文以全社会货运量来表征物流需求,根据熵关联度对影响物流需求的7个因素进行排序,分析各个因素对广西北部湾经济区物流需求的影响并提出相关建议.     

灰色周期关联度模型及其应用研究

灰色关联模型从统计序列几何形状的接近性和相似程序来判断其紧密程度,传统的灰色关联模型从统计序列的面积、斜率、变化速率等角度来计算其关联程度,这些关联模型受到统计序列横纵坐标(周期和振幅)的双重影响,这在分析统计序列间的单个因素间的关系时会产生其它因素的干扰。针对这一缺陷,本文提出了周期关联度模型,研究仅受周期因素影响的关联模型,证明该模型只与波形的波动周期和方向有关,不受曲线振幅的影响,且能表示出正负相关性,并应用该模型研究了GDP与居民消费间的周期关联性,取得了良好的效果。     

权重信息完全未知的灰色多属性群决策方法研究

基于灰色系统理论的思想和方法,探讨了决策方案的属性值为区间灰数、属性权重及各决策人的权威权重完全未知的灰色多属性群决策问题。通过分析,引入了个体理想最优方案向量、理想专家、方案间优势度和方案集中方案间优势比较矩阵等概念。根据区间灰数的本质特征,定义了两区间灰数的新的相离度,构建了基于两区间灰数相离度的灰色区间关联系数公式及灰色关联度。建立了基于投影的特征向量法和模糊互补判断矩阵排序方法的两种决策算法,给出的算法避免了权重的计算。文中实例分析说明了所提出的灰色多属性群决策方法的合理性及其算法的有效性。     

一种新的灰色绝对关联度模型及其应用

为了处理序列曲线间的负相关等问题,并使关联满足一定的性质,基于灰色关联分析的基本思想,本文利用数列曲线的平均相对变化态势构建了一种新的灰色绝对关联度模型,并探讨了模型的唯一性、对称性、相似性、平行性、一致性等性质,而后以新模型对我国及各省市区产业结构的有序度进行了测算,结果表明新模型计算简单,计算量小,更与实际相符。     

基于网络搜索信息的农村水环境质量灰色预测模型

针对农村水环境直接监测数据相对缺乏、间接数据难以有效引入的问题，综合灰色关联分析和预测模型，提出一种基于网络搜索信息的农村水环境质量灰色预测模型。首先，综合考虑数据重要性和可获得性，确定农村水环境相关的搜索关键词清单；然后，采用主成分分析法提取搜索关键词的主要特征，构建初始网络搜索变量，并利用灰色绝对关联度衡量各初始网络搜索变量与水环境质量之间的关联程度。在此基础上，构建不同频率数据的多变量离散灰色模型，将强关联变量的降频数据作为多变量离散灰色模型的驱动因素，从而构建基于网络搜索信息的农村水环境质灰色预测模型。实例分析结果表明，相对于传统灰色模型，引入网络搜索信息可以提高农村水环境预测精度，为农村水环境治理提供决策支持。     

基于灰色关联度分析法的PM2.5影响因素分析

本文主要对中国国家数据库中搜集到的20个主要城市的统计数据,运用灰色综合关联度法进行了系统分析,建立了对PM2.5的影响因素模型。结果表明:各PM2.5的影响因素与PM2.5含量的灰色综合关联度存在显著差异性,其中汽车尾气对于PM2.5的影响程度最为显著,其次分别为工业生产,生活污染和大气污染物,本文根据各影响因素的关联程度,对如何有效控制PM2.5含量提出建议。     

Criteria for selecting a production control philosophy

Logistic objectives constitute a compromise between having short leadtimes and a low volume of work in progress on the one hand and a high resource loading and due date obligation on the other. Miscellaneous production planning approaches offered today provide different combinations of logistic objectives for satisfying a manufacturing strategy. To combine the strength of the various approaches into a unified system, a new approach based on a dynamic and distributed production planning methodology is proposed. To customize the approach, various analyses and specifications have to be made and for that reason some important characteristics and criteria for analysing production control philosophies will be given.     

The social construction of the meaning of acute stressors: a qualitative study of the personal accounts of police officers using a stress counselling service

The police profession is one in which acute stressors are encountered more frequently than in other occupations. Using the personal accounts of 35 police officers attending an in-house stress counselling clinic, the aim of the present study was to provide a qualitative examination of how the institutional context of policing influenced the ways in which acute stressors signified to individual police officers experiencing felt distress. Using the framework of Rational Emotive Behaviour Therapy as an analytical tool, it is argued that beliefs contributing to the experience of felt distress are related to the way in which policing as both an identity and an activity is constructed through the police organizational culture. Not only do these constructions influence the ways in which officers perceive themselves and their environments, but they also operate at the collective level to 'normalize' some emotional responses and to 'pathologize' others which, it is argued, could impact upon the outcomes of interventions such as stress counselling.     

The moderating role of social support in Karasek's job strain model

This paper examines whether social support is a boundary-determining criterion in the job strain model of Karasek (1979). The particular focus is the extent to which different sources of social support, work overload and task control influence job satisfaction, depersonalization and supervisor assessments of work performance. Hypotheses are tested using prospective survey data from 80 clerical staff in a university setting. Results revealed 3-way interactions among levels of support (supervisor, co-worker, non-work), perceived task control and work overload on levels of work performance and employee adjustment (self-report). After controlling for levels of negative affect in all analyses, there was evidence that high levels of supervisor support mitigated against the negative effects of high strain jobs on levels of job satisfaction and reduced reported levels of depersonalization. Moreover, high levels of non-work support and co-worker support also mitigated against the negative effects of high strain jobs on levels of work performance. The results are discussed in terms of the importance of social support networks both at, and beyond, the work context.     

Job insecurity, coping resources and personality dispositions in occupational strain

This paper presents research on the relationships between the work-related stressor of perceived job insecurity and various indicators of occupational strain, taking into account employees' personality dispositions (trait negative and positive affectivity) and coping resources. Respondents were 222 Australian public servants surveyed during organizational restructuring that involved downsizing and threat to job certainty. The research was formulated within an adaptation of Osipow, Doty, and Spokane's (1985) framework of stress-strain-coping that included the possible direct as well as moderating effects of personality dispositions in reporting occupational strain (Parkes, 1990). Findings from hierarchical regression analyses indicate consistent significant independent effects of personality dispositions, coping resources and perceived job insecurity on various indicators of strain. There was also support for the moderating roles of negative affectivity and self-care in the relation between perceived job insecurity and physical strain. Implications for the role of dispositional factors, especially negative affectivity, and the utility of various coping resources in accounting for occupational strain in times of threatened job security are discussed.     

Introduction to Special Section on Sensitivity Analysis and Summary of NCSU/USDA Workshop on Sensitivity Analysis

This guest editorial is a summary of the NCSU/USDA Workshop on Sensitivity Analysis held June 11–12, 2001 at North Carolina State University and sponsored by the U.S. Department of Agriculture's Office of Risk Assessment and Cost Benefit Analysis. The objective of the workshop was to learn across disciplines in identifying, evaluating, and recommending sensitivity analysis methods and practices for application to food‐safety process risk models. The workshop included presentations regarding the Hazard Assessment and Critical Control Points (HACCP) framework used in food‐safety risk assessment, a survey of sensitivity analysis methods, invited white papers on sensitivity analysis, and invited case studies regarding risk assessment of microbial pathogens in food. Based on the sharing of interdisciplinary information represented by the presentations, the workshop participants, divided into breakout sessions, responded to three trigger questions: What are the key criteria for sensitivity analysis methods applied to food‐safety risk assessment? What sensitivity analysis methods are most promising for application to food safety and risk assessment? and What are the key needs for implementation and demonstration of such methods? The workshop produced agreement regarding key criteria for sensitivity analysis methods and the need to use two or more methods to try to obtain robust insights. Recommendations were made regarding a guideline document to assist practitioners in selecting, applying, interpreting, and reporting the results of sensitivity analysis.     

Job stress, job strain, and psychological withdrawal among Dutch university staff: towards a dualprocess model for the effects of occupational stress

This study examined the antecedents of job strain (emotional exhaustion, health complaints) and withdrawal behaviour (e.g. lowered organizational commitment) among a cross-sectional sample of 131 academic staff members of the law department of a large Dutch university. Conservation of resources theory (Hobfoll, 1989) provided the theoretical background for this study. Strains and withdrawal behaviours were expected to be most prominent among those who reported having few resources and/or who reported high job demands. Structural equation modelling revealed that this was indeed the case. As predicted, differential patterns of effects emerged for job demands and job resources. Analysis of the effects of four job-specific stressors revealed that especially the structural aspects of a staff member's teaching task (e.g. the number of students in their classes) contributed strongly to perceived job demands. Theoretical and practical implications of the study are discussed.     

Distinguishing traumatic, vicarious and routine operational stressor exposure and attendant adverse consequences in a sample of police officers

Problems in studying occupational stress within the police service are identified and the paucity of work on operational duties as potential stressors are discussed. The present study reports the results of a factor analysis of operational stressors (N = 601 serving British police officers) that revealed three factors: exposure to death and disaster; violence and injury; sexual crime. These were demonstrated to be reliable scales and were included in logistic regression models together with a range of demographic and psychological variables. Models were applied to men and women separately, which showed there to be different predictors of the likelihood of suffering distress (measured by the General Health Questionnaire, GHQ) in terms of the officer's gender and operational role. Overall the model for women officers was better at predicting psychological distress than that for men. These findings are related to aspects of the police occupational culture. Further discussion is offered that conceptualizes police operational stressors as traumatic, routine and vicarious. Finally, some implications are drawn for the provision of stress intervention in the light of this differentiation.     

Dermal Uptake of 18 Dilute Aqueous Chemicals: In Vivo Disappearance‐Method Measures Greatly Exceed In Vitro‐Based Predictions

Average rates of total dermal uptake (K_up) from short‐term (e.g., bathing) contact with dilute aqueous organic chemicals (DAOCs) are typically estimated from steady‐state in vitro diffusion‐cell measures of chemical permeability (K_p) through skin into receptor solution. Widely used (“PCR‐vitro”) methods estimate K_up by applying diffusion theory to increase K_p predictions made by a physico‐chemical regression (PCR) model that was fit to a large set of K_p measures. Here, K_up predictions for 18 DAOCs made by three PCR‐vitro models (EPA, NIOSH, and MH) were compared to previous in vivo measures obtained by methods unlikely to underestimate K_up. A new PCR model fit to all 18 measures is accurate to within approximately threefold (r = 0.91, p < 10^?5), but the PCR‐vitro predictions (r > 0.63) all tend to underestimate the K_up measures by mean factors (UF, and p value for testing UF = 1) of 10 (EPA, p < 10^?6), 11 (NIOSH, p < 10^?8), and 6.2 (MH, p = 0.018). For all three PCR‐vitro models, log(UF) correlates negatively with molecular weight (r² = 0.31 to 0.84, p = 0.017 to < 10^?6) but not with log(vapor pressure) as an additional predictor (p > 0.05), so vapor pressure appears not to explain the significant in vivo/PCR‐vitro discrepancy. Until this discrepancy is explained, careful in vivo measures of K_up should be obtained for more chemicals, the expanded in vivo database should be compared to in vitro‐based predictions, and in vivo data should be considered in assessing aqueous dermal exposure and its uncertainty.     

Systems Resilience for Multihazard Environments: Definition,Metrics, and Valuation for Decision Making

The United Nations Office for Disaster Risk Reduction reported that the 2011 natural disasters, including the earthquake and tsunami that struck Japan, resulted in $366 billion in direct damages and 29,782 fatalities worldwide. Storms and floods accounted for up to 70% of the 302 natural disasters worldwide in 2011, with earthquakes producing the greatest number of fatalities. Average annual losses in the United States amount to about $55 billion. Enhancing community and system resilience could lead to massive savings through risk reduction and expeditious recovery. The rational management of such reduction and recovery is facilitated by an appropriate definition of resilience and associated metrics. In this article, a resilience definition is provided that meets a set of requirements with clear relationships to the metrics of the relevant abstract notions of reliability and risk. Those metrics also meet logically consistent requirements drawn from measure theory, and provide a sound basis for the development of effective decision‐making tools for multihazard environments. Improving the resiliency of a system to meet target levels requires the examination of system enhancement alternatives in economic terms, within a decision‐making framework. Relevant decision analysis methods would typically require the examination of resilience based on its valuation by society at large. The article provides methods for valuation and benefit‐cost analysis based on concepts from risk analysis and management.     

UNIX系统性能监控简述及shell系统资源统计程序

本文简要阐述了unix系统中(主要以IBM的AIX为例)进行系统性能管理的几种命令行工具,并通过编写shell实例程序,运用其中提到的工具实现系统资源利用率的统计程序,为做好unix系统管理和调优提供参考.