EXPRESSING INVENTORY CONTROL POLICY IN THE TURNOVER CURVE

Estimation of the inventory level for an entire class of items is a valuable time saver when control of inventories at the aggregate level, rather than the item level, is of interest. Inventory approximation by location in supply chain network configuration and evaluation of inventory control policy shifts, are two examples of application. In this article, various popular inventory policies are related to a general function known as an inventory turnover curve that expresses inventory levels from the combined demand of multiple items. By knowing some basic item characteristics of representative items in a product class, the type of inventory policy being used, and the current aggregate inventory level, an inventory turnover curve can be constructed. This resulting turnover curve can be used to estimate inventory levels within 4.6%, on the average, of theoretically predicted ones.     

Locating a Biorefinery in Northern Spain: Decision Making and Economic Consequences

Biofuels are emerging as a prominent renewable and sustainable energy sources in developed countries. In this sense, this paper presents a case study in which a biorefinery has to be sited in Northern Spain. Thus, the strategic decision of locating such a facility is deeply investigated through strategic policy evaluation. Then, tactical decisions ranging from purchasing and transportation policies to storage protocols are carried out. Only local and limited biomass can be harvested for supplying the biorefinery through a heterogeneous vehicle fleet. Moreover two different and mutually exclusive storage strategies are evaluated: direct supply from crops to biorefinery and using intermediate-collectors. Additionally, crop exploitation factors and biorefinery sizes are used to generate several scenarios in which the strategic decision of location as well as all the tactic decisions are made. Some mixed integer linear programming models are proposed to figure out all relevant decision problems.The results suggest that the Northwest study area as the best option to locate the biorefinery and recommend the intermediate-collector storage strategy. Moreover, the key information about critical biomass, crops and times are also provided.     

Improving spatial accessibility to regional health systems through facility capacity management

In austerity times, the general interest to reduce costs and improve efficiency levels often resulted into local cuts to public expenditure and profound reorganizations of existing service networks, especially in sectors like healthcare. In Italy, a recent reform prescribed the reconfiguration of time-dependent (i.e. emergency) hospital networks with the aim of improving patients’ accessibility conditions. In order to evaluate the impacts determined by this reorganization, we perform a spatial analysis in which we consider the distance from the closest facility as an accessibility measure. Results obtained from the spatial analysis confirm that users effectively benefit from the reorganization process but also that further improvements are possible, especially for the worst served ones. To this end, we also propose solving a mathematical programming model aiming at redistributing the capacities, i.e. the supply of beds, among the hospitals of the network seeking to maximize users’ accessibility. The realized computational experiments show that averagely better and even more equitable accessibility conditions could be obtained by containing the deriving reorganization costs.     

浅层地温热能在设施农业中的应用研究——以天津市宁河县潘庄镇地区为例

本文介绍了温室冬季供热采用浅层地热能作为热源,地源热泵供热系统作为加热方式的应用研究。本课题旨在通过浅层地热能资源调查研究和地源热泵技术利用适宜性研究,查明天津市宁河县潘庄镇齐心庄村土地开发整理项目区的地温能源分布特征、资源量、地源热泵提取地温热能的适宜性及其各项技术参数,为土地开发整理的综合规划设计、长期发展战略和制定相关管理政策提供依据,实现科学、合理、慎重、有效地提高土地整理后的土地高效利用之目的。分析结果表明,浅层地温供热系统比传统供热系统节能28.8%。实验温室供热系统COP值为3.79,与采用燃煤供热系统的温室相比,温室相对节能47.4%。     

建立适应中小企业特征的信贷组织机构

商业银行传统信贷组织不按企业规模分部门,束缚着信贷部门支持中小企业的积极性,不利于专业化管理。近年来,各商业银行纷纷设立信贷专营机构进行信贷组织管理体制改革,一定程度上提升了服务中小企业的能力,但目前无论理论上还是实践中认识差异较大。作者认为,支持中小企业发展的信贷机构既要体现中小企业融资特点,还要体现组织机构设置原则,更要同商业银行组织机构改革态势保持高度一致,而将流程银行思想引入中小企业信贷组织机构是必然选择。     

A tabu search heuristic for redesigning a multi-echelon supply chain network over a planning horizon

This paper addresses the problem of redesigning a supply chain network with multiple echelons and commodities. The problem belongs to a comprehensive class of network redesign problems previously introduced in the literature. Redesign decisions comprise the relocation of existing facilities to new sites under an available budget over a finite time horizon, the supply of commodities by upstream facilities, the inventory levels at storage facilities, and the flow of commodities through the network. The problem is modeled as a large-scale mixed-integer linear program. Feasible solutions are obtained by using a tabu search procedure that explores the space of the facility location variables. The latter prescribe the time periods in which changes in the network configuration occur. They are triggered by the setup of new facilities, which operate with capacity transferred from the existing facilities, and by closing the latter upon their entire relocation. As the problem is highly constrained, infeasible solutions with excess budget are allowed during the course of the search process. However, such solutions are penalized for their infeasibility. Computational experiments on realistically sized randomly generated instances indicate that this strategic oscillation scheme used in conjunction with tabu search performs very well.     

白洋港铁水联运车船直取模式研究

白洋港作为长江三峡的核心内陆港,是工业输出港、翻坝转运港和西部出海港,主要服务于白洋工业园区,担当西北地区物流陆水联运的作用。为实现白洋港铁水联运的无缝衔接,在阐述白洋港铁水联运模式及作业流程的基础上,针对白洋港既有铁水联运模式存在的问题,提出白洋港铁水联运车船直取模式,从车船直取模式设施布局及作业流程进行分析,达到压缩无效作业时间、提高白洋港铁水联运效率、释放技术站作业能力等效果,实现白洋港铁水联运效率的提升。     

A supply chain network design considering transportation cost discounts

This study addresses an integrated facility location and inventory allocation problem considering transportation cost discounts. Specifically, this article considers two types of transportation discounts simultaneously: quantity discounts for inbound transportation cost and distance discounts for outbound transportation cost. This study uses an approximation procedure to simplify DC distance calculation details, and develops an algorithm to solve the aforementioned supply chain management (SCM) problems using nonlinear optimization techniques. Numerical studies illustrate the solution procedures and the effects of the model parameters on the SCM decisions and total costs. Results of this study serve as a reference for business managers and administrators.     

Exploring pilgrim satisfaction on facilities for religious events: a case of Ratha Yatra at Puri

This article relates to the annual Ratha Yatra festival at Puri, India, and aims at quantifying the pilgrim perception of the event on three major aspects of every facility – adequacy, quality, and signage – to measure their satisfaction. A questionnaire survey (N?=?680) was conducted, from which a five-factor structure was extracted using exploratory principal component analysis, further examined through partial least squares-path modeling. The final model was found to have significant positive effects on three factors that comprised adequacy and quality of physiological needs, quality of ancillary facilities, and signage. The outcome may be utilized in planning other pilgrim events for achieving a higher pilgrim satisfaction score.     

A two-stage approach to defining an affected community based on the directly affected population and the sense of community

Studies have demonstrated the inadequacy of relying on existing administrative boundaries or simple proximity to define an affected community. The proposal and siting of hazardous facilities can have a range of impacts upon people across wide areas, with some more affected than others as a result of living with the physical impacts of construction or the fear associated with perceived risk. We term those most affected the directly affected population and propose a two-stage model for identifying an affected community which places those most affected at the centre of the definition. The second stage is to identify the relationships those most affected have with the wider elements of the sense of community to discover the existing community or communities which are affected. Illustrated by the siting of a low-level radioactive waste disposal facility at Dounrey in the north of Scotland, we show that elements of the lived community experience may have very different shapes, extents and conflicting interests which pose challenges for their incorporation into a siting process. The two-stage model presented in this paper, by placing those most directly affected at the centre and working from there out into the existing communities, identifies issues early in any siting process to improve their incorporation and amelioration.