考虑权力结构及供应商竞争的生鲜供应链决策

考虑消费者新鲜度偏好,研究了两竞争性供应商和单零售商组成的生鲜农产品供应链决策问题.针对供应链的3种权力结构：供应商领导(SS)、无领导(VN)和零售商领导(RS),构建生鲜农产品供应链的两阶段博弈模型.结果表明：1)SS情形下,当两竞争性供应商的产品品质差异值高于临界值时,零售商会向低品质供应商订货;否则,零售商会向高品质供应商订货;2)VN情形下,生鲜农产品品质提升导致批发价格上升,但不一定伴随着销售价格的上升,且产品品质提高导致批发价格上升的阈值大于产品品质导致销售价格上升的阈值;两供应商之间的竞争越激烈,均衡时的批发价也就越低,但零售商边际利润越高;3)RS情形下,供应商提供的生鲜农产品新鲜度越高,零售商获取的该生鲜农产品边际利润也就越高,但竞争供应商边际利润不变.4)3种情形下,当生鲜农产品的品质较低且低于临界值时,VN情形时供应商利润最低,SS情形下供应商获得的利润高于RS情形.     

基于消费者效用的生鲜农产品供应链生鲜度激励机制研究

生鲜供应链整体生鲜度的提升对减少浪费、提高供应链整体盈利水平及社会福利有重要意义。本文基于消费者效用理论研究了两供应商和单一零售商组成的供应链系统，构建了单周期下生鲜农产品生鲜度激励模型，模型以供应商为领导者，采用Stackelberg博弈方法求解得到了均衡状态下供应商、零售商的最优定价策略及供应商新鲜度努力选择。研究结果表明，供应商和零售商利润与消费者价格敏感系数呈反向变化，与新鲜度敏感系数呈同向变化。在价格竞争市场，供应商保鲜努力程度和利润与价格替代率呈反向变化；在生鲜度竞争市场，供应商保鲜努力程度和利润与新鲜度替代率呈同向变化。基于研究结论，厂商及政府应当联手引导消费者的消费观念，尽可能减少由于信息不对称引致的道德风险，在市场价格替代率不变甚至降低的情形下，提高生鲜度替代率，使得消费者的意愿支付价格上升，提高自身讨价还价能力，获取更多利润。     

供应商保鲜努力的生鲜农产品双渠道供应链协调决策研究

在互联网迅猛发展的时代,生鲜农产品双渠道营销模式是供应商的最佳选择,如何发挥双渠道优势,实现渠道共赢是目前研究的热点。以供应商主导的双渠道供应链为研究对象,考虑新鲜度衰减且扰动需求和供应商保鲜努力,对比分析集中和分散决策模型,论证构建协调模型的必要性。从渠道合作和利润最大化的角度出发,设计两部定价契约、批发价协调契约和由成本分担与补偿策略构成的混合协调契约,三种契约均能在一定范围内有效实现供应链协调,提高各成员的利润。最后,对比分析所设计协调契约以认识其本质,并通过数值分析验证其有效性。     

考虑绿色与保鲜努力水平的供应链双渠道同价与异价决策与协调研究

绿色度、新鲜度和定价策略是农产品供应链运作绩效的关键影响因素。考虑绿色与保鲜努力水平双重因素,构建Stackelberg博弈模型,对生鲜农产品供应链双渠道同价与异价决策进行比较,并提出契约协调策略,最后通过算例仿真进行可行性验证。研究发现：（1）同价或异价策略下,最优批发价、最优绿色/保鲜努力水平、市场需求总量以及供应商利润均保持不变,而集中决策下最优努力水平、市场需求量以及供应链总利润均优于分散决策。（2）集中或分散决策下,当线上线下渠道市场占有率失衡时,异价策略更有利于调配渠道销售资源,促使线上线下渠道需求量趋于均衡,零售商利润与供应链总利润均优于同价策略;当线上线下渠道市场占有率均衡时,同价与异价策略均可以采用。（3）“双向成本分摊+收益共享”契约可使最优努力水平达到集中决策水平,同价与异价策略下供应链各主体利润均得到Pareto改善,供应链实现完美协调。     

考虑消费者效用与保鲜的生鲜农产品EOQ模型

针对生鲜农产品新鲜度随时间减小的特点,构造受生鲜农产品新鲜度和零售价格影响的消费者时变效用函数,分析了消费者在不同时刻够买生鲜农产品的效用和数量的变化,并基于此建立了消费者偏好影响需求的生鲜农产品EOQ模型;以提高消费者效用为目的,分析了两种不同保鲜情形下零售商的最优订货决策和最优保鲜投入。研究发现,零售商的最优保鲜投入并不能使消费者效用最大化,满足消费者对生鲜农产品新鲜度的要求必须依靠政府的宏观调控。     

考虑保鲜努力与增值服务的生鲜电商供应链最优决策与协调

针对一个生鲜电商与一个生鲜供应商组成的供应链，其中生鲜电商负责销售农产品并提供增值服务，而生鲜供应商负责农产品的保鲜配送。考虑保鲜努力与服务水平均会影响生鲜农产品的市场需求，通过构建集中式与分散式下的生鲜电商供应链决策模型，分析了新鲜度需求弹性、服务需求弹性等因素对最优决策的影响，并对比分析了分散式与集中式决策下的最优决策。在此基础上，设计了"收益共享-双向成本分担"契约，通过合理设计契约参数实现了生鲜电商供应链的完美协调与帕累托改进。最后，进一步深入分析了供应链在协调前后的最优决策变化，并用数值算例进行了考察与验证。研究发现：供应链在协调后必然会提高产品新鲜度与服务水平，但可能会导致更低或更高的生鲜农产品销售价格。当新鲜度需求弹性与服务需求弹性较低时，生鲜电商在协调后会制定相对更低的产品价格，实施"优质低价"策略；而在新鲜度需求弹性或服务需求弹性高于某一水平时，生鲜电商在协调后会制定相对更高的产品价格，实施"优质优价"策略。     

新鲜度信息不对称下生鲜农产品供应链协调

生鲜农产品供应链上下游存在新鲜度信息的不对称性,加剧了耗损。为此,迫切需要研究生产商隐瞒新鲜度信息的生鲜农产品供应链协调。基于Stackelberg博弈,使用单周期报童模型分别构建生产商和零售商的利润函数,分析供应链性质;并提出具体的回购契约形式进行供应链协调。研究认为：一般的批发价格契约下,即使生产商隐瞒农产品新鲜度信息,也不一定损害供应链总收益;回购契约可以保证新鲜度信息共享并协调供应链。最后,通过数值算例验证分析结论的有效性。     

盟员行为偏好下生鲜农产品供应链生鲜努力激励机制与协调研究

本文建立了"合作社+核心企业"模式下两阶段折扣定价的二级生鲜农产品供应链，基于消费者生鲜偏好、价格敏感度对市场需求的影响，选取Nash谈判解作为公平参考点，引入合作社公平偏好理论，研究供应链盟员保鲜投入决策。针对合作社保鲜努力激励，探讨供应链盟员偏好对保鲜努力水平以及收益共享契约激励协调效果的影响。研究发现，消费者生鲜偏好的提高能够促进收益共享契约的激励效果，并且提高合作社公平效用。同时，收益共享契约在第一阶段对保鲜努力水平的激励效果优于第二阶段，而在第二阶段联合使用收益共享和成本分摊能够显著提高该阶段的保鲜投入。     

基于消费者选择行为的生鲜农产品保鲜和定价策略研究

针对生鲜农产品易变质的特性以及消费者偏好的多样性,构建了价格和新鲜度影响下的消费者时变选择模型,基于零售商所面临的初始订货数量变化或潜在市场容量变化,分析了零售商对于生鲜农产品的最优定价及最优保鲜投入。结果表明,当潜在市场容量较小时,零售商通过保鲜所获得的利润增加值、最优定价及最优保鲜投入均随着初始订货量的增加而减小;当潜在市场容量较大时,零售商的保鲜利润增加值和最优定价仍然随着初始订货量的增加而减小,但最优保鲜投入却随着初始订货量的增加而增大。     

零售商主导下促进绿色产品需求的联合研发契约协调研究

针对绿色环保产品价格过高,阻碍其成为主流消费品这一现实问题,在绿色经济背景下,探讨零售商向负责绿色研发成本投入的制造商提供不同联合研发契约时的供应链均衡策略和协调问题。以零售商主导的双边垄断型绿色供应链为研究对象,在考虑消费者环保意识、产品绿色度水平、价格等多种因素影响需求的基础上,分别探讨批发价契约、成本分担契约和两部制契约对绿色产品需求、供应链成员利润及渠道利润的影响。结果表明,成本分担契约无法实现供应链成员利润的Pareta改进;一定条件下,两部制契约可以实现供应链成员利润的双赢,并提高绿色产品的市场需求。此外,虽然消费者环保意识的提高并不总是会带来绿色产品市场需求的增加,但却总是会使得绿色供应链的利润提高;并且较高的消费者环保意识将激励企业追求一个较低的绿色成本系数,从而促使企业积极进行绿色技术创新努力。     

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.     

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.     

Job strain and psychotropic drug use among white-collar workers

The main objective of this study was to measure the association between simultaneous exposure to high psychological demand and low decision latitude at work and the use of psychotropic drugs among white-collar workers. A second objective was to determine whether social support at work modified this association. A cross-sectional study was performed that included 2786 workers from the public sector in the Greater Quebec City area. A self-administered questionnaire was used in order to evaluate psychological demand, decision latitude and social support at work. Psychotropic drug use was measured over a period of 2 days. The prevalence of psychotropic drug use among the participants was found to be 3.9%, even though 20.5% were exposed to job strain. The association between job strain and psychotropic drug use, after adjustment for social support at work, age, gender, education, family income, employment status, occupation, stressful life events, cigarette smoking, alcohol consumption and physical activity, was statistically significant (odds ratio: 4.5, 95% CI 1.7?12.2). Social support did not appear to modify this association. The results of this study suggest that job strain might be a determinant of psychotropic drug use among white collar workers. Social support at work does not appear, however, to modify this association.     

Role clarity, work overload and organizational support: multilevel evidence of the importance of support

The present study extended the demands-control-support model used in occupational stress research in two ways. First, it hypothesized that role clarity (i.e. role ambiguity), like control, would moderate the relationship between demands and psychological strain. Second, the study assessed support (from leaders) as a macro characteristic of the work-group environment. Data were drawn from a large study of US army soldiers, the study sample consisting of 1786 lower enlisted male soldiers. The inclusion of support as a work-group characteristic lead to a multilevel test of the model. A three-way multilevel interaction among work demands, role clarity and support was observed. As predicted, the relationship between demands and psychological strain was moderated by role clarity; however, this moderating relationship was found only when work-group support was high.     

Leadership, levels of analysis, and déjà vu: Modest proposals for taxonomy and cladistics coupled with replication and visualization

In the inaugural issue of LQ's Yearly Review of Leadership, Hunt and Dodge (2000, p. 442) note that, “Within the last two decades, one of the crucial developments in organizational research in general, and in leadership research specifically, is the articulation of specific levels of analysis and their implications for theory building, measurement, and observation.” Their original observations are updated by extending the inferential logic of Yammarino, Dionne, Chun and Dansereau (2005) to determine if any increase in the utilization of a level of analysis perspective has occurred in the last five years. The possible evolution of leadership theory and analysis is discussed, especially with reference to Relational Leadership Theory, Leader–Member Exchange, and Individualized Dyadic Theory. Proposals incorporating taxonomic and visualization tools as a means to help bridge the stakeholder gap are also offered.     

Information Frictions in Trade

It is costly to learn about market conditions elsewhere, especially in developing countries. This paper examines how such information frictions affect trade. Using data on regional agricultural trade in the Philippines, I first document a number of observed patterns in trade flows and prices that suggest the presence of information frictions. I then incorporate information frictions into a perfect competition trade model by embedding a process whereby heterogeneous producers engage in a costly sequential search process to determine where to sell their produce. I show that introducing information frictions reconciles the theory with the observed patterns in the data. Structural estimation of the model finds that information frictions are quantitatively important: roughly half the observed regional price dispersion is due to information frictions. Furthermore, incorporating information frictions improves the out‐of‐sample predictive power of the model.     

The Economics of Density: Evidence From the Berlin Wall

This paper develops a quantitative model of internal city structure that features agglomeration and dispersion forces and an arbitrary number of heterogeneous city blocks. The model remains tractable and amenable to empirical analysis because of stochastic shocks to commuting decisions, which yield a gravity equation for commuting flows. To structurally estimate agglomeration and dispersion forces, we use data on thousands of city blocks in Berlin for 1936, 1986, and 2006 and exogenous variation from the city's division and reunification. We estimate substantial and highly localized production and residential externalities. We show that the model with the estimated agglomeration parameters can account both qualitatively and quantitatively for the observed changes in city structure. We show how our quantitative framework can be used to undertake counterfactuals for changes in the organization of economic activity within cities in response, for example, to changes in the transport network.     

Modelling end-of-life product recovery chains - a case study

European Union legislation, and existing national legislation of many European countries, mandates that manufacturers take back and recover their electronic and electrical equipment. If manufacturers are to comply with legislation, models need to be developed for these activities. Whilst infrastructural and technological deficits exist and must be addressed, so too must the organization of recovery, from a business perspective. In this paper, models of resource recovery are presented and a case study described.