考虑供应风险的多源应急物资采购双层规划模型

自然灾害频繁发生,事故灾难不断涌现,公共卫生事件猝不及防,社会安全风险交织叠加,给人们的生产和生活带来了巨大的风险和不确定性。在突发事件背景下,考虑应急物资供应中的各类风险,激励多源应急物资的稳定供给,受到党和政府高度重视。应急物资供应有哪些风险,如何规避这些风险,针对多种渠道的采购,如何优化采购结构。这些问题是本论文关注的重点。本文以政府、制造型企业、受灾地区民众为决策主体的三级供应链为基础,构建了上层以整个供应链系统收益最大化为目标函数、下层以供应风险最小化为目标函数的双层规划模型,对不同情景下物资采购订单的分配进行研究。在此基础上,本文以某市洪涝灾害为例进行分析,证明了模型的可行性,并探究了供应风险变化对物资采购订单分配、以及整个供应链系统收益的影响,以期为政府应急物资采购决策提供参考性建议。     

损失规避偏好下的定制件采购决策分析

讨论了有损失规避偏好的按单制造企业所面临的定制件采购决策问题. 由于采购提前 期较长,在产品设计完成之前提前采购,有助于保证顾客订单的按期交货,但是会造成大量呆 滞库存品;在产品设计完成之后进行关键件的采购,会减少呆滞库存量,但是会造成顾客订单 的延期交货. 如何权衡呆滞库存与延期交货,除要考虑各种成本与收益因素之外,还要考虑决 策者的风险偏好. 假定决策者具损失规避效用函数,而且顾客订单不能部分交货条件下,在建 立问题的数学模型之后,讨论了最优采购决策的存在性,分析了损失规避程度、部件需求不确 定性以及部件本身特性对最优采购策略的影响. 分析结果显示,损失规避制造企业的采购行为 在一定的条件下和风险中性、风险规避制造企业不同,也不同于直觉判断. 这将有助于采购策 略、供应契约的设计及供应链的协调管理.     

基于模糊权重的多目标订单分配模型

随着竞争的日益加剧,采购成了影响企业生存和发展的关键因素。在这种情况下,正确的订单分配是成功实行采购的关键。实际上,影响订单分配的许多信息并不是确定的已知条件,例如目标、约束条件和影响权重等。本文通过考虑上述信息的不确定性和模糊性,构建一个包含模糊目标、模糊权重和随机约束的订单分配模型。然后,利用数值算例证明了模型的可解性。最后,指出了未来可能的几个研究方向。     

中断与质量多重风险下的供应链动态采购策略研究

新冠病毒疫情的暴发对全球供应链稳定造成了较大冲击,导致多种风险凸显。本文建立马尔科夫决策模型,研究由两个供应商、一个制造商与两类零售商组成的供应链在应对供需中断与质量多重风险下的多期动态采购决策问题,并比较了检查与延期付款两种质量控制机制对采购决策的影响。研究表明,供应中断风险不会影响延期付款机制下的采购决策,但在检查机制下,供应中断风险越高,越倾向于采购高质量产品;区域需求中断风险与供应中断风险对采购决策的影响是一致的,不同的是区域需求中断会降低整体的采购量。同时,在高质量产品库存较低时,提高检查精度或延长延期付款期,会使得制造商向低质量的供应商采购;而在高质量产品库存较大时,延期付款机制会使制造商向高质量供应商采购,但检查机制下制造商不会改变采购决策。此外,比较检查与延期付款机制可知,在次品率较低时,制造商应选择检查机制,反之则应选延期付款机制,但这种选择会随着中断风险而改变,在中断风险越高时,增加检查精度并不能提高制造商的收益,但延长延期付款期可以提高制造商的收益。     

供应风险下双源采购批发单价拍卖最优设计

考虑多个具有供应风险和成本私有信息的潜在供应商,研究了供应商投标批发单价的最优双源采购拍卖机制设计.首先,针对一般的采购商收益函数,求出了最优的订货量分配规则和供应商投标均衡,并分别与单源采购及对称信息对比,发现双源采购拍卖增加了采购商和供应商的期望利润,不对称信息对供应商有利但对采购商和供应链不利.然后,分别针对报童及垄断环境,进一步分析了双源采购拍卖下的订货分散程度、信息价值和双源采购价值,发现,订货分散程度与供应风险及两个获胜者的利润率贡献相近程度正相关;高成本获胜者比成本较低者索取更高的单位信息租金,导致不对称信息下的订货分散程度比对称信息下低;供应风险越高或投标人数越多时,双源采购价值越大.     

不同突发事件下进口原油采购策略

石油对经济生活的重要性不言而喻,中国原油的高对外依存度及集中的进口来源区域引起我们对能源安全的广泛关注,如何有效最小化国际原油价格波动和供应短缺或中断带来的风险,制定突发事件影响下的最佳采购策略是我们必需关注的焦点,但目前结合突发事件的采购策略研究还不足。论文通过采用符合中国原油进口习惯的月度数据,建立了突发事件下的CVaR模型,综合考虑价格波动、供应中断造成的GDP冲击和战略石油储备因素,分析三种不同突发事件情景下的原油进口采购策略。研究表明：当预期中东区域出现危机时,非洲和欧洲/俄罗斯是增加采购量的理想选择,若迪拜价格波动不剧烈,亚太采购量也可适当增加;对于仅仅只有价格变动,动用战略石油储备降低风险有限,只有当供给中断时,动用战略储备才能发挥巨大的降低风险,更好的减少对国民经济冲击的作用。本文在最小化原油进口风险值且同时考虑进口来源多样化、风险、成本及价格变动率的情况下,构建的基于CVaR的应急原油进口采购策略模型,丰富了该领域的研究成果,为中国原油进口采购策略提供了具体可操作的参考。     

考虑不确定履约率的全局鲁棒供应组合决策研究

生产和采购的全球化为供应链企业带来了更多的复杂性与不确定性。收集全面信息和使用有效的工具是控制决策风险、减少不确定性危害的有效途径。在供应商选择与订单分配管理中,供应商履约率是影响企业供应组合决策的主要因素,如何对其进行定量刻画是迫切需要解决的问题。已有的研究通常是由期望方法或鲁棒方法来刻画履约率。然而,期望履约率法往往忽略了履约率的波动性,从而造成需求损失;而鲁棒履约率法通常存在过于保守、退化过于迅速两个缺点,使企业承担不必要的成本。本文研究供应商选择与订单分配决策问题,使用全局鲁棒优化的两个不确定集合来刻画供应商履约率,同时给出了这一问题的确定性鲁棒表达和一种多项式时间求解算法。最后,通过仿真实验证实本文的全局鲁棒优化模型可克服期望模型和一般鲁棒模型的缺点。本文提出的算法能有效求解本文全局鲁棒优化等价确定性问题,为企业的供应商选择和订单分配决策提供更为灵活精确的辅助工具。     

考虑供应风险的竞合供应链决策研究

随着供应链的全球化和商业环境的瞬息万变，如何应对供应风险，是企业运作管理中需考虑的核心问题之一.本文采用建模分析法研究了近年来运作实践中新出现的一种风险应对策略——与对手合作，并建立了如下供应链竞合模型：模型考虑一个产品制造商需向一个具有随机中断风险的供应商采购某种核心零部件以制成产品，并与对手在市场上展开竞争，其中对手是一个能够自己生产该零件并制成产品的集成制造商；在供应商的供应中断发生后，产品制造商可以从竞争对手处对零部件进行补货.研究发现，在上游供应商获得订单且发生供应中断的前提下，两个制造商之间的补货合作一定会达成，这意味着补货合作选项具有风险应对效应.然而从总体上看，依赖于市场潜能、供应的可靠性、产品间的替代性以及成本的大小，两个制造商之间的竞争与合作既可能共存，也可能互斥(即只竞争不合作或只合作不竞争).除此之外，区别于既往文献的经典研究结论——“下游企业紧急补货选项的存在使具有供应风险的(上游)主供应商获得的订货量减少”,本文在引入供应链竞合之后却发现：补货合作选项的存在竟然会使具有供应风险的上游供应商获得的订货量增加，即两个制造商之间的合作具有向上的溢出效应.而且本文还发现，与没有合作选项的情形相比，合作的存在使两个制造商投放到市场的产品总量增加，即两个竞争性制造商之间的补货合作还具有向下的溢出效应——降低了市场价格从而提高了消费者剩余.     

Web混合模式下面向订单装配的生产管理系统

本文介绍了一种面向订单装配的制造企业生产管理系统的实现方案,通过运用计算机网络、数据库处理和现代企业管理技术开发出集企业订单处理、生产计划控制、采购处理和财务处理等功能于一体的面向订单装配的生产管理系统.充分利用B/S、C/S混合模式的优点,克服了目前单一模式下的缺陷,能及时有效地实现企业内部各部门之间以及企业和客户之间的信息互动,对制造企业动态应对市场,及时准确地掌握信息资源并做出正确的生产计划决策,具有重要意义.本文具体介绍了Web混合模式下面向订单装配的生产管理系统构建方案和系统基本功能.     

REAL模型在内部控制制度设计中的运用实例

本文运用REAL模型,分别对企业的业务过程、信息过程和管理过程的风险进行分析,并针对业务过程的采购/付款过程、信息过程和管理过程的风险,用REAL模型来有效地进行内部控制设计。     

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.