基于无缺陷退货的网上销售易逝品供应链协调模型

本文针对网上在线销售易逝品的无缺陷退货现象,考虑了供应链的最优订购协调问题。利用一个两阶段动态规划来描述动态市场环境下网上销售商的两次订购行为,在假定在两个销售阶段都发生无缺陷退货现象的前提下,分别建立了集中和分散决策模型,同时设计了价格保护契约以实现供应链的协调运作。最后,利用数值仿真得出了一些重要的管理启示。通过研究发现：（1）当不确定性较大时,网上销售商需要在第1阶段多订购产品以应对需求风险,因此导致了较低的系统期望利润。并且,需求的不确定性越大,供应链协调越有价值。（2）当第1阶段或第2阶段退货率或两阶段退货率都增加时,两个阶段的最优订购量均减小。（3）对于需求波动性较高的产品,顾客的退货率越小或者可服务退货率越大,价值越高（即对供应链系统期望利润的提高越显著）。     

考虑退货价格的易逝品供应链协调性研究

考虑由一个制造商和一个零售商组成的供应链,制造商以批发价格为零售商提供一种易逝品,零售商再以零售价格将产品销售给顾客;零售商以一定的退货价格回收顾客的退货产品,制造商对零售商的顾客退货产品及销售季节结束后的剩余产品进行回收,零售商的退货价格不仅对产品的需求有影响,而且对顾客的退货率也产生影响.在这样的条件下,建立了需求不确定环境下顾客退货及制造商回收的模型,结果表明,制造商简单回收顾客的退货产品和销售季节结束后的剩余产品并不能实现供应链协调,而基于回馈与惩罚策略的制造商回收策略能够实现供应链的协调.最后,给出了供应链协调下的模型优化方法,并以数值实例计算了易逝品供应链协调下的最优退货价格和最优订货量,并分析了各种参数变动对最优退货价格、最优订货量和集中式供应链最优利润的影响.     

考虑跨渠道退货的双渠道供应链最优策略

基于零售商线上线下销售与消费者退货并存的双渠道供应链,构建考虑退货的双渠道供应链定价模型以及考虑跨渠道退货策略的双渠道供应链定价决策模型。通过理论分析和数值实验对比,研究集中决策与分散决策下的零售商最优定价策略以及总利润的变化情况,同时分析在不同退货策略下顾客偏好以及退货率对零售商定价和收益的影响。结果表明：零售商渠道的最优价格设置与顾客对渠道的偏好成正比,与退货率成正比。当顾客对某一渠道偏好程度高时,分散决策下的利润要高于集中决策,并且随着该渠道退货率的提高,这种利润差距会进一步扩大,因此零售商应实施分散决策的渠道策略,鼓励线上线下两个渠道进行竞争,从而获得更大的收益。从仿真结果可以看出,对于一般的服装产品,提供跨渠道退货服务的零售商总利润更高,在一定条件下跨渠道服务水平的投入会增加零售商的收入,但这种投入应该控制在一个合理的水平上,并保持服务与顾客回报之间的正相关关系。     

含有自治复原退货物流的单周期库存问题研究

研究电子商务模式中含有自治复原退货物流的单周期库存控制问题.在考虑退货价对需求影响的基础上,通过引入可再售退货产品率,将退货品分为可再销售和不可再销售两部分进行分析,以销售商的利润最大化为目标,借助报童模型建立了自治复原退货物流下考虑退货价对需求影响的单周期库存模型,分析模型中最优订货量、退货价和利润的求解方法,通过数值分析探讨模型中各参数(退货价对需求的影响因子、退货率、可再售退货率)对利润、最优退货价和订购量大小的影响以及造成这些影响的原因.研究结果发现,商家应该在制定策略时考虑退货价对需求的影响,并大胆地提出和宣传自己的退货政策,以增加顾客对退货价的敏感度,从而获取更多的利润.     

基于无缺陷退货下的三阶层易逝品供应链的协调性研究

通过将销售努力对需求和退货率的影响引入三阶层易逝品供应链,建立了需求不确定环境下顾客退货及制造商、分销商分级回收模型,指出分散式供应链在三方没有任何缔结契约条件下并不能实现协调,而基于回馈与惩罚策略下逐层回收顾客的退货产品及销售季节结束后的剩余产品能够实现供应链的协调。     

再制造不确定的MR闭环供应链系统建模与仿真研究

为了探讨再制造逆向物流对供应链成员企业以及系统整体的影响,利用控制理论对原产品生产商和下游零售商组成的MR两级闭环供应链系统进行研究,建立随机再制造环境下的系统动态模型,探讨分散决策下生产商与下游零售商之间的闭环供应链运作问题。通过计算机仿真研究MR系统的动态行为和运行规律,分析再制造战略对原产品生产商和下游零售商生产运作的影响,探讨逆向物流的不确定性、回收率以及提前期因素对MR系统经济收益的影响。研究结果表明,当原产品生产商从事废旧产品回收再制造时,其新产品生产环节会因逆向物流的不确定性出现明显波动,这种负面影响会波及到下游零售商,但是相对生产商本身而言,再制造对下游零售商的影响较轻微。从经济层面看,提高产品回收率、降低再制造环节的不确定性可以达到改善系统绩效的目的,尽可能保持新产品生产过程与再制造过程的同步有助于提升成员企业以及系统的总利润。     

基于退款保证的线上零售商体验渠道策略研究

在由制造商和线上零售商组成的O2O供应链中,考虑消费者退货行为,构建了基于退款保证的供应链博弈模型,探究线上零售商选择体验渠道的动机及其影响。研究发现：当线上零售商选择体验渠道策略时,各企业均会改变各自的定价策略,其中制造商会提高批发价格,线上零售商则根据其退货损失来调整零售价格,但体验渠道策略能提升二者的利润水平;随着体验渠道的引入,能够激励部分消费者放弃退货（即退货率降低）,从而有利于提升消费者福利。然而,从利润最大化的视角,线上零售商可能不会有动机选择体验渠道策略,这取决于产品退货率以及产品退货对消费者造成的退货损失,但退款保证能增大线上零售商引入体验渠道的动机。     

企业物流绩效评价指标体系研究

<正>传统的生产加工型企业多注重生产盈利,在企业物流绩效管理方面大多有所欠缺,本文根据企业物流服务企业供应链运作的特性,参考供应链运作参考模型(SCOR),分析与之五个环节相配套的物流服务,建立企业的物流绩效评价指标体系,并阐述了其设计理念、设计原则和设计步骤。     

两阶段价格和需求变动产品的供应链协调

通过建立两阶段动态模型研究了价格和需求变动产品的供应链协调问题。首先建立了集中协调、分散无协调和分散收入共享协调三种模式下供应链的动态规划模型;证明价格和需求变动时供应链在不同模式下存在最优解,应用改进的收入共享契约可以协调供应链系统并取得集中协调供应链系统的绩效,并可实现供应链利润的任意分配;给出了协调契约参数的确定方法;讨论了价格、市场需求风险变化对供应链协调绩效及最优契约参数的影响;通过数值实验分析证明了改进的收入共享契约可以使系统各方共同承担风险及分享利润,使各方绩效达到Pareto最优。     

电子商务企业产品最优定价与退货策略研究

本文分析了电子商务企业退货物流的现状,并回顾了国内外学者关于退货策略和定价的相关研究成果.将退货策略与最优价格引入消费者效用和企业利润的研究之中,基于此构建了消费者效用模型与企业利润模型,给出了最优退货策略与产品价格的组合,分析了不同定价和消费者偏好变化对消费者效用与企业利润的影响.实例研究验证了本文推理的合理性和有效性,为企业决策提供了理论依据和有效方法.     

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.     

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.     

Power,authority and legitimacy

Management, human resources, organization, control, leadership, etc., all seem to be just so many euphemisms for power, and this suggests a discourse of management and organization that calls things by their proper name. This paper on the contrary stresses the need to resolve the concept of ‘power’ itself into more differentiated notions, and proposes that clarification may be derived from distinctions once explicit in the vocabulary of Classical antiquity, but lost in modern European languages. It argues that nothing but confusion in thinking about organizations, management and legitimation can result from the failure to recognize that the phenomena this vocabulary identifies and distinguishes are irreducibly different.     

Employees' perceptions of organizational restructuring: the role of social support

Organizational change and restructuring is often perceived as leading to increased occupational stress, impacting negatively on the psychological well-being of employees. This pragmatic study investigates the role of social support and dispositional affect as moderators of role stress post-restructuring for employees in a public utility company. A total of 176 employees, including 37 managers, 60 graded staff and 78 industrial staff completed a self-report questionnaire, approximately 1 year postrestructuring, retrospectively assessing role conflict, ambiguity, overload and positive and negative feedback pre- and post-restructuring. Results suggested that overall role stress increased for managers/ senior officers and graded staff, but not for industrial staff. Social support was linked with lower role stress, more positive feedback and less negative feedback at post-restructuring. For certain role stressors this impact was moderated by dispositional affect, but the effect was not consistent across occupational groups. Positive affect enhanced the effect of manager support in reducing role conflict for graded staff, and the effect of co-worker support in increasing positive feedback and reducing negative feedback for industrial staff. Findings suggest that managers should pay particular attention to support and feedback for employees during periods of chronic occupational stress following organizational restructuring.     

The Danish psychosocial work environment and symptoms of stress: the main, mediating and moderating role of sense of coherence

The aim of this cross-sectional study was to explore the main, mediating and moderating role of sense of coherence (SOC) on stress symptoms and on the association between perceived psychosocial work environment and stress symptoms. The sample includes 2053 Danish employees from 52 workplaces. Hierarchical regression models were applied for each measure of stress. The results strongly supported the presence of a main effect for SOC. People with high levels of SOC experienced fewer stress symptoms. A mediating effect of SOC was also supported. Thus, SOC in part explained the association between work environment and stress symptoms. In addition, some support for a moderating effect of SOC was found, suggesting that people with higher SOC coped more efficiently with work environmental strain that people with lower SOC. Taken together the regression models explained 11-32% of the variance in stress symptoms. The results suggest that measures of individual factors such as SOC should be included in analyses of the effects of work environmental factors on stress and well-being.     

Control at work: a generalized resource factor for the prevention of musculoskeletal symptoms?

During the last two decades two potent groups of predictors for work-related musculoskeletal problems have been identified: physical work load and poor psychosocial working conditions. However, little is known about their combined effects. In this study the buffering effect of control at work with respect to the negative effects of psychological demands and physical work load on musculoskeletal problems is examined. All study variables were sampled from 431 people working in geriatric nursing homes in Germany by means of questionnaires. Main effects and interactions were tested with multiple regression analysis. The results showed that control buffered the effects of high psychological demands, but not of high physical work load; the buffering effect of control was observed only when physical work load was low. The combined effects of demands and physical work load were over-additive. Thus, the power of different predictors for musculoskeletal symptoms depended on the level of other predictors. This suggests that the efficiency of certain strategies for the prevention of musculoskeletal problems is likely to depend on the level of risk factors, with different strategies being appropriate for different levels of risk.     

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.     

Comparison of Chemical Screening and Ranking Approaches: The Waste Minimization Prioritization Tool versus Toxic Equivalency Potentials

Chemical screening in the United States is often conducted using scoring and ranking methodologies. Linked models accounting for chemical fate, exposure, and toxicological effects are generally preferred in Europe and in product Life Cycle Assessment. For the first time, a comparison is presented in this article of two of the prominent, but structurally different methodologies adopted to help screen and rank chemicals and chemical emissions data. Results for 250 chemicals are presented, with a focus on 12 chemicals of interest in the United Nations Environment Programme's Persistent Organic Pollutants global treaty negotiations. These results help to illustrate the significance of described structural differences and to assess the correlation between the methodologies. The scope of the comparison was restricted here to human health, although the insights would be equally useful in the context of the health of ecosystems. Illustrating the current types of chemical screening and emissions comparison approaches, the relative significance of the scenario and structural differences of the Waste Minimization Prioritization Tool (WMPT) and the Toxic Equivalency Potential (TEP) methodologies are analyzed. The WMPT facilitates comparison in terms of key physical-chemical properties. Measures for Persistence, Bioaccumulation, and Toxicity (PBT) are calculated. Each PBT measure is scored and then these scores are added to provide a single measure of relative concern. TEPs account for chemical fate, multipathway exposure, and toxicity using a model-based approach. This model structure is sometimes considered to provide a less subjective representation of environmental mechanisms, and, hence, an improved basis for screening. Nevertheless, a strong relationship exists between the two approaches and both have their limitations.     

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.