Lead time aggregation: A three-echelon supply chain model

In this paper, destructive effects of upstream aggregated stochastic lead times on the supply chain (SC) performance are analyzed. For this purpose, a three-echelon SC consisting of one producer, one distributor, and one retailer is modeled. Both the producer and distributor face stochastic lead times, which can be also aggregated to create a long unpredictable lead time. In order to scale down shortages at the retailer site, an incentive scheme is proposed to convince the upstream members to increase their reorder points. Applying the coordinated model considerably increases the total profit earned by the whole SC as well as all SC members.     

浅谈结构件涂装屏蔽工艺改进方法

装载机结构件在涂装前需用抛丸的方法,对工件表面进行预处理,增强对油漆的附着力。由于结构件上有工作装置安装孔,且安装孔的粗糙度要求较高(Ra3.2),因此在涂装时机加孔的屏蔽很重要。本文针对已有屏蔽方法在实际应用中存在的一些缺点,分析原因并制定改善措施,改进涂装屏蔽工艺。通过采用橡胶屏蔽轴套与屏蔽钢套结合的屏蔽方法,解决了单一屏蔽方法存在的问题,在一定程度上加快了结构件面漆化进程。     

基于成本的供应链企业中RFID应用与协调研究

以VMI模式的两级供应链为研究对象，通过比较应用RFID前后的供应链成本变化情况，得到RFID应用的约束条件，并设计了上下游企业的成本分担机制，以达到供应链整体的Pareto改进，最后进行算例验证。运用了提前期压缩量与平均库存费用的关系模型来分析库存成本，使得企业通过历史需求数据就能做出判断而不需要预测未来需求，且以平均库存为基数确定库存缩水量，更贴近实际。     

芦子园铅锌矿水文地质条件与地质环境评价

芦子园铅锌矿是"西南三江成矿带"近年取得的重大突破的矿床之一[1]。矿床类型属沉积改造—矽卡岩型铅锌矿床[2]。自探明其铅锌储量以来,对该区水文地质的工作日益增加,因此也取得了一些成果。本文通过对芦子园矿区的水文地质基本特征、含(隔)水层(组)划分、地下水化学特征以及采用富水系数法和水动力学法对矿坑涌水量进行预测来阐明矿区水文地质条件,并且对矿区地质环境进行介绍和评价,提出相应的治理完善的措施,为矿区内安全生产提供科学依据。     

桩基灌注桩工程质量控制

随着我国经济社会的不断发展,基础建设工程显得越来越重要,其中的桩基工程则是保证基础建设工程质量的根本。灌注桩作为常见的桩基施工工程之一,其质量控制一直是桩基工程施工管理中探讨的课题。桩基灌注桩工程质量控制主要是通过加固软基等处理方式来提高基础承载力,为此,必须采取科学而合理的施工工艺,并强化对成桩的质量控制。     

创新引领、产业升级与地区基本实现现代化

产业结构是地区现代化的重要构成要素, 通过产业结构优化升级来实现地区现代化是发达国家和地区的通常做法。 目前我国许多地区已经处于工业化的中后期阶段, 科技创新开始成为引领区域产业结构升级的基本动力。 创新引领产业升级, 当前迫切需要实现从招商引资到招才引智, 从被动利用外资企业技术溢出到主动走出去寻求技术, 从利用后发优势到采取先发战略, 从创新与创业脱节到产学研一体化, 从追求 “大而全” 到形成各具特色的区域产业网络的战略变迁。     

低品位厚矿体电耙出矿底部漏斗式采矿法在峪耳崖金矿的应用

峪耳崖金矿通过进行采矿工艺革新,提出了电耙出矿漏斗式底部结构浅孔留矿采矿法,并详细介绍了该采矿方法的构成要素、采切工程布置、回采步骤以及矿柱回收方法等,具有一定的借鉴和指导意义。     

Facets of operational performance in an emergency room (ER)

This paper, using detailed time measurements of patients complemented by interviews with hospital management and staff, examines three facets of an emergency room’s (ER) operational performance: (1) effectiveness of the triage system in rationing patient treatment; (2) factors influencing ER’s operational performance in general and the trade-offs in flow times, inventory levels (that is the number of patients waiting in the system), and resource utilization; (3) the impacts of potential process and staffing changes to improve the ER’s performance. Specifically, the paper discusses four proposals for streamlining the patient flow: establishing designated tracks (“fast track,” “diagnostic track”), creating a “holding” area for certain type of patients, introducing a protocol that would reduce the load on physicians by allowing a registered nurse to order testing and treatment for some patients, and potentially and in the longer term, moving from non-ER specialist physicians to ER specialists. The paper’s findings are based on analyzing the paths and flow times of close to two thousand patients in the emergency room of the Medical Center of Leeuwarden (MCL), The Netherlands. Using exploratory data analysis the paper presents generalizable findings about the impacts of various factors on ER’s lead-time performance and shows how the proposals fit with well-documented process improvement theories.     

Optimal time phasing and periodicity for MRP with POQ policy

This paper deals with component supply planning for assembly systems where several types of components are ordered from external suppliers to produce a single type of finished product. Actual component lead times are often different from those contracted because of random delays. An MRP approach with periodic order quantity (POQ) policy is used for the supply planning of components. Our aim is to find the optimal values of the order periodicity and planned lead times at the offsetting step of the MRP procedure. The goal is to minimise the sum of the average component holding, finished product backlogging and setup costs. Several theoretical properties of the objective function are proven and an efficient optimization algorithm is developed. The proofs of the explicit form and properties of the objective function as well as the development of the optimization algorithm occupy a large portion of this paper. The method developed can be used for the optimization of time phasing and periodicity for such an MRP system under lead time uncertainties.     

冯营矿煤层卸压带宽度浅析

通过对24121运输巷未施工钻孔巷道煤层瓦斯含量的测定和钻孔漏气深度的测定,得出巷道卸压带宽度规律,为合理选择煤层瓦斯抽采钻孔的封孔深度提供了依据,优化了抽采钻孔布置,实现了对煤层瓦斯抽采钻孔的封孔方法的科学管理。