An integrated production–distribution model for the dynamic location and allocation problem with safety stock optimization

The design and management of a multi-stage production–distribution system is one of the most critical problems in logistics and in facility management. Companies need to be able to evaluate and design different configurations for their logistic networks as quickly as possible. This means coordinating the entire supply chain effectively in order to minimize costs and simultaneously optimize facilities location, the allocation of customer demand to production/distribution centers, the inbound and outbound transportation activities, the product flows between production and/or warehousing facilities, the reverse logistics activities, etc.Full optimization of supply chain is achieved by integrating strategic, tactical, and operational decision-making in terms of the design, management, and control of activities. The cost-based and mixed-integer programming model presented in this study has been developed to support management in making the following decisions: the number of facilities (e.g. warehousing systems, distribution centers), the choice of their locations and the assignment of customer demand to them, and also incorporate tactical decisions regarding inventory control, production rates, and service-level determination in a stochastic environment. This paper presents an original model for the dynamic location–allocation problem with control of customer service level and safety stock optimization. An experimental analysis identifies the most critical factors affecting the logistics cost, and to finish, an industrial application is illustrated demonstrating the effectiveness of the proposed optimization approach.     

On the Problem of Identification in Multiplicative Intensity-Rate Models with Multiple Interactions

In this paper we examine a multiplicative intensity model in which a covariate interacts with two other covariates in the same model. We demonstrate, analytically, that in such situations a log-linear parameterization based on two pairs of baseline levels cannot be transformed, uniquely, to the, otherwise equivalent, multiplicative parameterization. We show that the problem lies in an oversight of the conditional independence between the two covariates interacting with a common third covariate. As a solution, therefore, we propose an approach that takes due account of such dependence. Our proposed approach uses a common baseline level for the three covariates involved in interaction while estimating the corresponding relative intensities. The issues addressed are illustrated with a demographic data set involving the estimation of rates of transition to parenthood.     

VMCI 下基于批发价决策权转移的供应链效率改进研究

本文在VMCI 模式下,考虑销售努力水平对市场需求的影响,研究批发价决策权由供应商转移至零售商的两级供应链效率改进问题。假定零售商决策批发价和销售努力水平,供应商决策寄售量,建立了零售商主导的Stackelberg 博弈模型,证明了集中决策下的最优解和分散决策下的均衡解均存在且唯一,集中决策下的寄售因子大于分散决策下的对应值。随后,引入收入共享与销售努力成本共担契约,论证了系统中寄售因子保持不变、批发价降低,且当契约参数满足一定条件时,可实现帕累托改进,实现供应链的效率改进。最后,分析了契约参数对于系统决策变量及利润的影响。     

Entering new markets: The effect of performance feedback near aspiration and well below and above it

Research summary : This study draws on the resource‐based view and the behavioral theory of the firm to gain new insights about the effect of performance relative to aspiration level (i.e., performance feedback) on the decision to enter new markets. Results show an inverted U‐shaped relationship between performance both below and above aspiration level, and the probability of firms to enter new markets. That is, when firms are well below or well above their aspiration level, they significantly change their behavior. This article develops a theoretical framework to clarify and organize these findings. Managerial summary : This study examines the effect of performance feedback, and particularly, large discrepancies between firm performance and aspiration level on the decision to enter new markets. It provides support to the role of performance feedback in affecting the decision to enter new markets, a factor that has received relatively little attention in the extensive literature that has examined the inducements of such moves. Results show that, as performance falls below or rises above aspiration, a firm's probability of entering new markets increases up to a certain point after which this relationship decreases. This shows that the tendency to enter new markets is different for firms that are in the neighborhood of aspiration level compared to those that are well below or above it. Copyright © 2016 John Wiley & Sons, Ltd.     

不同模式农地整治前后农户生计资本变化研究

研究目的：探讨不同模式农地整治对农户生计资本水平和结构的影响及其差异。研究方法：组合赋权法,耦合协调度,双重差分模型。研究结果：农地整治后,整治区户均生计资本总指数和生计资本耦合协调度分别增加0.106 3和0.091 2,其中新型经营主体主导模式项目区分别增加0.143 3和0.129 6,政府主导模式项目区分别增加0.078 1和0.061 9,而同期未整治区分别增加0.010 4和0.006 4,说明农地整治是提高农户生计资本水平和改善农户生计结构的有效途径,且新型经营主体主导模式的农地整治的作用效果大于政府主导模式。研究结论：应继续加大农地综合整治项目投资力度,创新农地整治实施模式,以提升农户生计资本水平和改善农户生计资本结构。     

Can smallholder farmers adapt to climate variability,and how effective are policy interventions? Agent‐based simulation results for Ethiopia

Climate variability with unexpected droughts and floods causes serious production losses and worsens food security, especially in Sub‐Saharan Africa. This study applies stochastic bioeconomic modeling to analyze smallholder adaptation to climate and price variability in Ethiopia. It uses the agent‐based simulation package Mathematical Programming‐based Multi‐Agent Systems (MPMAS) to capture nonseparable production and consumption decisions at household level, considering livestock and eucalyptus sales for consumption smoothing, as well as farmer responses to policy interventions. We find the promotion of new maize and wheat varieties to be an effective adaptation option, on average, especially when accompanied by policy interventions such as credit and fertilizer subsidy. We also find that the effectiveness of available adaptation options is quite different across the heterogeneous smallholder population in Ethiopia. This implies that policy assessments based on average farm households may mislead policy makers to adhere to interventions that are beneficial on average albeit ineffective in addressing the particular needs of poor and food insecure farmers.     

激光对抗微光夜视仪研究综述

激光技术逐渐应用于现代军事方面,凭借其亮度高、成本低、指向性好的特点,可以很好地压制和破坏夜视仪等成像设备,提高我军夜间作战能力和防护能力,具有很高的应用价值。掌握其发展现状,可以加快相应激光压制设备的研制,改进应对激光的防护措施,具有重要意义。为此,本文调研近几年相关文献,总结研究进展,发现近相关研究集中于激光对抗微光夜视仪的损伤机理、效果评估和反制措施等三个方面。损伤机理方面针对夜视仪不同组件的损伤有大量分析;效果评估方面聚焦于数字图像处理方式改进评估手段;反制措施方面提出了多种防强光结构的夜视仪传感器。     

关于地方财政体制改革几个疑点问题的认识

当前地方财政体制改革中亟需破解的一些疑点问题地方财政体制改革必须坚持一体化分税制的目标,而在一体化的分税制框架内可给予各地自主选择空间和允许存在不同的过渡模式;取消乡级财政的条件已经基本成熟,把取消乡级财政作为地方财政层次改革的突破口,在完善配套措施后,考虑在全国推广“省管县”体制。一级政府一级财政”和“事权与财权统一”仍应是财政体制改革应遵循的基本理念。     

重庆市农村居民收入对消费的影响研究

在概述国内外关于收入与消费关系的研究现状的基础上,以重庆市为研究对象,分析收入在影响农村居民消费方面的作用.通过运用实证分析方法,分析不同收入阶层对消费的需求,发现收入差距是制约消费水平的重要因素.因此,促进农民增收,适当缩小不同收入阶层的收入差距,对于增加消费具有重要的意义.     

居民生态补偿支付意愿与支付水平影响因素分析——以黄河下游为例

文章以Probit、Tobit回归模型为主要工具,利用来自黄河流域下游山东省464份调查问卷的数据,研究了影响居民生态补偿的支付意愿与支付水平的主要因素。研究表明:影响居民生态补偿支付意愿与支付水平的因素并不完全相同。对生态环境问题的关注程度和性别因素显著影响居民的生态补偿支付意愿,但显著影响居民的生态补偿支付水平的因素是对黄河上游生态环境重要性的认识;另外,显著影响居民生态补偿支付意愿与支付水平的共同因素是对保护黄河上游生态环境需要大量投入的知晓程度和居民年收入。