Optimal production-inventory policy for make-to-order versus make-to-stock based on the M/Er/1 queuing model

This paper analyzes a multi-product production / inventory system where demands for each item arrive according to a Poisson process and the production time for each product has an Erlang distribution. The paper proposes an optimality condition that specifies whether each product should be produced make-to-stock or make-to-order. In the event a product should be produced make-to-stock, an approach for computing the optimal base-stock level is proposed. Numerical examples are given for illustrative purpose.     

A comprehensive decision making structure for partitioning of make-to-order, make-to-stock and hybrid products

Manufacturing systems produce their products by making use of three main strategies: make-to-order, make-to-stock and hybrid (combination of MTO and MTS strategies) systems. Hence, several products must be considered and partitioned in terms of many different conflicting criteria, leading to a large set of subjective or ambiguous data. Thus, an effective evaluation approach is essential to improve decision quality. In this paper a comprehensive decision, making structure is proposed to choose the proper strategy for producing the products. It consists of a novel hybrid methodology, which combines analytical hierarchy process (AHP) and technique for order performance by similarity to ideal solution (TOPSIS) for partitioning of products. In this study, the rating of each alternative regarding different criteria (throughout the TOPSIS technique) is described by means of linguistic variables. Furthermore, fuzzy AHP methodology is applied to determine the weights of evaluation criteria. At the end, the effectiveness of the proposed model is demonstrated through a case study.     

The role of the customer order decoupling point in production and supply chain management

In order to compete successfully, operations in any type of firm need to be strategically aligned to the market requirements. This concerns both manufacturing and supply chain operations. The customer order decoupling point (CODP) is getting increasing attention as an important input to the design of manufacturing operations as well as supply chains. This paper investigates the impact of the position and role of the CODP on issues of concern for production and supply chain management. The focus is on the design and strategic planning aspects of the supply chain, and the design of manufacturing planning and control systems. The paper proposes a dual design approach for production and supply chain planning systems; one type of system for operations upstream the CODP and another type of system for downstream operations in order to fully support the characteristics and objectives of each respective part of the supply chain.     

Collaborative production planning with production time windows and order splitting in make-to-order manufacturing

In this paper, we study a generalized production planning problem, that simultaneously investigates the two decisions that play critical roles in most firms, namely, production planning and order splitting and assignment. The problem takes into consideration the production time windows and capacities. We formulate the integrated problem as a linear mixed-integer program with a minimized total cost. A particle swarm optimization-based approach is developed to address the problem. Extensive computational experiments show that the proposed approach outperforms a commercial optimization package. Some managerial insights are also explored and reported. Finally, concluding remarks and future research directions are provided.     

A machine-to-loop assignment and layout design methodology for tandem AGV systems with multiple-load vehicles

In this paper, we propose a design methodology for tandem Automated Guided Vehicle (AGV) systems with multiple-load vehicles. Our goal is to devise a design methodology that can achieve the following objectives in multiple-load tandem AGV designs. The first objective is to achieve the workload-balance between vehicles of different loops. The second objective is to minimize the inter-loop flow. The final objective is to minimize the flow distance. To achieve these objectives, the following problems are studied. First, we conduct simulations to study the relationship between a vehicle's load-carrying capacity and work capacity. This relationship is then considered in the second problem, i.e. the problem of determining the machine content of each loop. A two-stage machine-to-loop assignment method is proposed for solving this problem. At the first stage, an initial machine-to-loop assignment is generated. This initial assignment is then improved at the second stage using Simulated Annealing (SA). The third problem is the problem of determining the layout of machines in each loop. A flow-line design method and SA are adopted for solving this problem. The fourth problem is the layout problem of guide-path loops. To solve this problem, a famous layout method found in the literature is adopted. The last problem includes the problem of determining the best orientation of each loop and the problem of finding the best places to set up transfer stations between adjacent loops. A mathematical programming model that can solve them simultaneously is proposed. Simulations are then conducted to verify the design, and to show that the proposed design methodology is indeed capable of producing good and satisfactory tandem AGV designs with multiple-load AGVs. Finally, it is our hope that the knowledge learned from this study can help us have a better understanding of multiple-load AGV systems and allow us to have successful implementations of similar systems in practice.     

Effects of combining product-centric control and direct digital manufacturing: The case of preparing customized hose assembly kits

The case study presents the effects of combining product-centric control and direct digital manufacturing (DDM) in the preparation of customized assembly kits. The theoretical contribution of the paper is in describing a combinatorial innovation in operations and production management: how to use product-centric control to make DDM highly efficient when there are many generic and partly generic production resources. Evidence is found of many beneficial outcomes such as waste reduction, simplified planning, and improved customer responsiveness for the case of preparing customized assembly kits for hydraulic hoses.     

A two-stage bid-price control for make-to-order revenue management

Capacity control implementations in make-to-order (MTO) revenue management typically are based on bid-prices, which are used to approximate the opportunity cost of accepting a customer request. However, in the face of stochastic demand, this approximation becomes less accurate and the performance of bid-prices may deteriorate. To address this problem, we examine the informational dynamics inherent in MTO capacity control problems and propose a two-stage capacity control approach based on bid-price updates. Updating is realized with neural networks, which are applied to adjust the selection criteria during the booking period with respect to online demand information. Not only is the resulting contribution margin positively influenced by the update, but also the downside risk of performing worse than a naive first-come-first-served policy. Results from computational experiments show that the proposed approach dominates traditional revenue management methods like randomized linear programming with and without resolving in expected contribution margin as well as in risk.     

基于订单生产的车间管理信息系统的设计及实现

从提高车间业务流程的绩效出发，对生产过程控制进行了优化设计，并在此基础上，采用面向对象技术对车间进行了类设计，建立了车间总体信息流框架，详细讨论了其软件实现方法。     

Make-to-order or make-to-stock decision by a novel hybrid approach

This paper presents a strategic decision-making structure to determine whether a particular product should be produced under make-to-order (MTO) or make-to-stock (MTS) strategy. A novel hybrid methodology consisting of strengths, weaknesses, opportunities and threats (SWOT) analysis and analytic hierarchy process (AHP) is proposed. Utilizing AHP in SWOT analysis diminishes one of the main deficiencies of this strategic approach that is the restriction of employing quantitative calculation to evaluate the factors that affect the decision. AHP method improves the quantitative information basis of strategic decision-making processes. The traditional AHP requires exact judgments, but due to the complexity and uncertainty involved in real world decision problems, it is sometimes unrealistic or even impossible to require exact judgments. Consequently, a commonly used decision-making method, fuzzy analytic hierarchy process (FAHP) is suggested. FAHP’s connection to SWOT yields a novel hybrid method for partitioning of MTO/MTS products. At the end, the proposed fuzzy AHP-SWOT methodology is validated through a real case study.     

面向制造业产品订货生产的供应链优化结构模型

随着用户需求的日益多样化和个性化，制造业中面向订货生产的供应链体现出了突出的优势。建立供应链优化的结构模型是进行供应链优化的前提。本文针对现有供应链结构模型存在的不足，建立了面向订货生产的供应链优化结构模型，详细讨论了模型的建立过程，并阐述了该模型所具有的优越性和对环境的快速适应能力，