An integrated inventory model involving manufacturing setup cost reduction in compound Poisson process

The collaboration of vendor and buyer is one of the key factors for successful supply chain management. The most common strategy for a cooperative system is to propose an integrated replenishment plan. Almost all inventory models assume that setup cost is deterministic and is not subject to control. However, in many practical situations, setup cost can be reduced at an added investment. The paper assumes that setup cost can be reduced at an added investment and shortage is permitted during the lead time. This article relaxes the assumption that the demand of lead time is deterministic and is assumed to be a compound Poisson process. A model is derived to determine an optimal integrated inventory policy with controllable setup cost. The expected annual integrated total cost function is derived and a solution procedure is established to find out the optimal solution. Finally, a numerical example is provided to illustrate the solution procedure.     

Optimal production and inventory decisions under demand and production disruptions

Unanticipated events may take place and disrupt demand and/or production in a supply chain. Conditional on the type, magnitude and duration of disruptions, changes may be called to revise the original production plan. We analyse different disruption scenarios and propose optimal production–inventory models for products facing demand and production disruptions. To lower the cost, we optimise the production run time, purchasing times and order quantity for the manufacturer. Numerical experiments are conducted to examine the influences of disruption time and magnitude on optimal production and purchasing decisions.     

考虑残次品和碳排放的供应链多级库存的EOQ模型

针对供应链多级库存系统,探析残次品与碳排放对该系统的影响作用与供应链库存持有成本、订购成本、运输成本和检查成本的构成函数,建立多级库存的EOQ模型,提供考虑残次品和碳排放的供应链订货经济批量和库存控制策略,并用算例验证了模型的有效性。     

基于加权求和算法的多目标订货决策模型

基于传统的EOQ模型,研究以制造商碳排放量最小化和制造商利润最大化为目标的多目标优化决策模型。模型中制造商的碳排放量并不是单纯的与订货量呈线性关系,而是考虑每次订货时,运输产生的碳排放量与订货次数呈线性关系,库存产生的碳排放量与库存量呈线性关系。采用加权求和的多目标规划解法对模型进行求解,分析了碳税对多目标决策的影响,发现不同隶属度权重下,多目标决策的订货量、需求和碳排放量均呈现出不一样的变化趋势,说明碳税政策对于企业具有明显的减排效果。对于环保意识强的企业,政府应该采取降低碳税的政策;对于重视经济利益的企业,政府应该增加碳税来减少碳排放量。     

Effects of carbon emission regulations on remanufacturing decisions with limited information of demand distribution

Policy-makers are developing regulation policies to drive down carbon emissions from industries. Independent remanufacturers (IRs), which remanufacture recycled products/components/parts, must manage and evaluate economic costs generated by the production under future carbon emission regulations. We present three optimisation models to determine the remanufacturing quantity that maximises the total profits under three common carbon emission regulation policies: (a) mandatory carbon emissions capacity, (b) carbon tax and (c) cap and trade. These models include sales revenue, remanufacturing cost, disposal cost, inventory holding cost, shortage cost and carbon emission cost. The max–min approach is used to solve the models, which assume limited information on demand distribution. We investigate how the three regulation policies affect remanufacturing decision-making for IRs and we also solve some numerical examples where we vary the magnitudes of incentives, penalties and stringency of constraints to provide implications to policy-makers. The results indicate that remanufacturers should aim to improve yield rate to maximise the profit irrespective of the implemented carbon emissions policy. Policy-makers should prefer the carbon tax policy, if any of the other two policies must be performed, a remanufacturing discount such as a higher carbon emission cap or lower penalty should be implemented to better promote the development of remanufacturers.     

Operational and environmental decisions for a two-stage supply chain under vendor managed consignment inventory partnership

Supply-chain-based organisations are nowadays facing intense pressure to abide to environmental regulatory requirements while they are striving to be responsive to customers’ needs at the least cost possible. As supply chain activities are among the top contributors to carbon emissions, several recent research works have investigated the impact of carbon regulation policies on economic and environmental supply chain performance. This paper presents integrated economic and environmental models for the one-vendor one-buyer supply chain problem under a vendor managed consignment inventory (VMCI) arrangement. Through the developed models, we study the impacts of two carbon reduction policies, namely carbon cap and carbon tax policies, on supply chain wide costs and carbon emissions. We first provide a much simpler and more compact formulation for the basic single-vendor single-buyer supply chain under VMCI agreement. We also present an environmental-based VMCI model where reduction of carbon footprint is considered as the only objective function. We then extend these two basic models to include each of the two carbon emissions reduction policies. We identify structural properties for the optimal solutions of the two hybrid economic and environmental models and propose algorithms to generate optimal solutions. The results of the computational experiments reveal that the implementation of carbon reduction policies, through carbon cap and carbon tax, may call for the adjustment of the vendor’s production and buyer’s delivery quantities to reduce carbon footprint without significantly increasing the operational costs.     

Impacts of collaborative investment and inspection policies on the integrated inventory model with defective items

For an imperfect production system, to reduce quality-related costs, a manager may consider investing capital in quality improvement. In general, the investment expense in reducing the defective rate of items is often paid by the vendor. On the other hand, the buyer may inspect the product quality as the order is received which implies it incurs an inspection cost. In a supply chain integrated system, to accomplish global optimisation, the vendor and buyer can agree to jointly invest capital to improve the imperfect production processes, and the buyer can remove the inspection programme as the defective rate reaches a certain low-level. Hence, this paper investigates the impacts of collaborative investment and inspection policies on an integrated inventory model with defective items. The objective of this study is to seek the optimal order quantity, shipping times from the vendor to the buyer per production run, and the defective rate that minimise the joint total cost per unit time. An algorithm is developed to find the optimal solution. Several numerical examples are presented to demonstrate the proposed model and solution procedure, and then several management insights are obtained from the numerical examples.     

Effect of rework,rejects and inspection on lot size with work-in-process inventory

The economic order quantity and economic production quantity models are the most commonly used inventory models in production environments for the calculation of optimum lot size. However, these models are based on the unrealistic assumption that every process produces good quality products every time. Moreover, the impact of inspection is neglected in all extended inventory control models involving work in process inventory. By taking both imperfect production and lot size inspection into consideration, this paper presents a more realistic approach for the modelling of optimum lot size and total cost with a focus on the work in process inventory. A mathematical model is derived for optimum lot size based on the minimisation of the average cost. Our approach incorporates the effect of rework, rejects and inspection on work in process inventory. The significant effect of imperfect production and inspection on optimum lot size is evaluated via numerical examples. In comparison to existing models, the proposed model is a more generalised and flexible form of inventory model for independent demands.     

Increasing the return on investment from federally-funded research and development

Abstract

Each year, the United States invests approximately $495 billion in research and development (R&D) – about a quarter of the total global investment. While the private sector accounts for about 67% of U.S. investment, the Federal government plays a critical role in funding R&D, particularly in areas that address societal needs in which the private sector does not yet have sufficient clear or strong incentive to make the required investments. The Federal government invests approximately $150 billion each year in R&D conducted at Federal laboratories, universities and other research organizations. As Federal R&D investments wind down or are completed, additional work is often still needed to translate the knowledge accrued from that R&D into products and services that will improve lives and provide economic growth. Technology transfer is the process by which existing knowledge, facilities or capabilities developed through R&D are utilised to fulfill public and private need. The transfer of technology from federally-funded R&D to the private sector is crucial to realising the taxpayer’s return on investment in the Federal R&D ecosystem. However, moving innovations from the lab to the market is more than inventing products for people to buy. Technology transfer is about creating jobs and growing the economy; ensuring a strong, secure, and resilient Nation; and improving Americans’ health and environment, fostering the conditions for America to maintain leadership in global innovation.     

基于持续抽检的电力物资多阶段动态采购模型及系统

针对电力物资集中采购模式中由于采购批量大、合同周期长而导致的不稳定供应问题,提出一种多阶段迭代修正式的电力物资动态采购模型,运用持续质量抽检进行供应商动态调整。首先根据经济订购批量模型确定最佳招标批次、划分标包,并设定多阶段招标模式及供应商评价指标体系;同时依托供应商绩效评价系统,获取历史抽检数据并迭代预测各供应商物资质量,通过建立标包份额动态分配模型动态修正供应商供应量。通过具体案例对模型进行了示例和验证,并对产品质量与供货量的关联性进行了敏感性分析,为采购方有效控制物资质量、供应商提高中标率提供了指导。最后,介绍了项目组开发的一个基于移动物联网的电力物资送检系统,为本文所提的评价模型提供了可行的实施环境。     

“双碳”目标下制冷空调行业技术发展的思考

绿色低碳发展已成为全球共识。中国是全球最大的能源消费国,也是全球最大的温室气体排放国。实现碳达峰碳中和是推动中国高质量发展的内在要求,也是国家的重大战略决策。制冷空调行业作为能源消耗和温室气体排放大户,在国家节能减排事业中有着不可或缺的责任和义务。"双碳"目标对行业而言是一场革命性的挑战,将带来全产业生态链的革新和重构。技术创新是制冷空调行业实现"双碳"目标的重要途径,全行业应持续加大技术创新投入力度,以更加节能环保的技术和产品服务于经济和市场需求。为国家层面的"双碳"目标完成做出应有的贡献,也由此推动全行业早日实现由大到强的根本转变。     

新经济时代科技发展与餐具设计

以新经济时代为背景,分析材料科学与信息科学对餐具设计的影响,研究这些科技在餐具设计领域中的具体应用与未来的发展前景,论述了科技与餐具形态表达之间的相互关系,从而启发设计师突破传统设计手法,从应用新科技的角度入手进行设计表达,使餐具产品不仅具有多媒体性,易操控性,还要向人性化、情趣化方向更好地发展,提高人们的生活品质。