A review and evaluation on constructive heuristics to optimise product mix based on the Theory of Constraints

In this paper, we address the problem of defining the product mix in order to maximise a system's throughput. This problem is well known for being NP-Complete and therefore, most contributions to the topic focus on developing heuristics that are able to obtain good solutions for the problem in a short CPU time. In particular, constructive heuristics are available for the problem such as that by Fredendall and Lea, and by Aryanezhad and Komijan. We propose a new constructive heuristic based on the Theory of Constraints and the Knapsack Problem. The computational results indicate that the proposed heuristic yields better results than the existing heuristic.     

TOC会计

主要介绍TOC的基本原理、TOC会计以及产品组合。     

Framework for understanding the complementary nature of TOC frames: Insights from the product mix dilemma

The product mix problem has been discussed in the management science literature for decades, and in the Theory of Constraints literature since Goldratt and Fox first presented the simple P's and Q's problem. This paper will investigate the product mix dilemma using a variety of Theory of Constraints approaches that complement and extend traditional treatments such as Linear Programming, spreadsheet and graphical approaches. The Theory of Constraints approaches include the product mix algorithm, Five Focusing Steps, Evaporating Cloud and reality trees. The paper will surface insights and draw out implications arising from the use of these different approaches, and show how the choice of Theory of Constraints tool reflects, in essence, a 'framing' of the problem in different ways. We will show that while the various Theory of Constraints frames are complementary in nature, they may also substitute for each other to some degree. As a result, we suggest there is in most cases no one best frame, and the often implicit search for a 'best-fit' frame should be recognized and abandoned. It is argued that there should be greater acceptance of the use of a variety of frames that help us deal with the inevitable ambiguities and complexities that arise in the real world. The application of the framing approach is demonstrated using a real case. Finally, the authors' experience with the use of this and other examples of framing in teaching will be briefly discussed.     

Bi-level multi-objective mathematical model for job-shop scheduling: the application of Theory of Constraints

This study highlights a different systematic approach to the application of Theory of Constraints (TOC). The work describes the decisions involved in the implementation of TOC in a job-shop environment as a bi-level multi-objective mathematical model. On the first level, the decision is made by minimising idle time on the bottleneck to generate the initial schedule. The second level decision is to improve additional performance measurements by applying the multi-objective technique, while maintaining the bottleneck sequence obtained from the first level decision. Moreover, the concept of transfer lot is also adopted in this model to reduce the waiting time on each machine by allowing overlapped operations. The concept of transfer lot is applied as the constraint on earliest starting time for each job on each machine in the proposed mathematical model. Additionally, the machine set up time and product demands are also adopted to make the model practical to use in the real situation. The numerical examples for both single and multiple bottleneck cases are given to demonstrate how this approach works. The commercially available optimiser, the LINGO 10 software package, is used to solve the examples and the result shows how this approach works in practice.     

An algorithm for optimizing joint products decision based on the Theory of Constraints

A particular decision-making process that is needed by most firms who produce joint products is the one requiring an assessment of desirability of further processing joint products beyond the split-off point. The purpose of this paper is to develop an algorithm for optimizing a joint products further processing decision under the theory of constraints. To fit the jointly produced characteristic of joint products and the sequential produced characteristic between each joint product and its further processing product, the algorithm is composed of seven steps. These steps consider every bottleneck resource to the decision-making process by computing a priority ratio to establish its priority sequence. According to the priority sequence of the most constrained resource, the initial master production schedule is developed. Then, the following steps find the best path to reach the optimal solution under the guidance of all bottleneck resources. Due to its accessibility and comprehensibility, the TOC-based algorithm developed by this paper is a practical tool for obtaining the optimal joint products further processing decision.     

基于约束理论的线边库存优化应用

根据约束理论的5个关键步骤,深入分析装配生产线线边库存产生的各个环节,采用相应工具找出最大限制因素.基于持续改善的思想,将瓶颈工序的任务分摊给其他环节,把系统中的限制因素变为非限制因素进而达到企业线边库存水平的优化目标.案例中,试运行装配线每日1.5h成熟度由65%提高至95%.企业的实际应用表明,约束理论在线边库存中的应用提高了企业效率,适用于线边库存的优化管理.     

Emergence,consolidation and dominance of meta-regimes: Exploring the historical evolution of mass production (1765–1972) from the Deep Transitions perspective

Grand environmental and societal challenges have drawn increasing attention to system innovation and socio-technical transitions. A recent Deep Transitions framework has provided a comprehensive theory of the co-evolutionary patterns of multiple socio-technical systems over the last 250 years. However, so far the framework has not been subjected to systematic empirical exploration. In this paper we address this gap by exploring the co-evolutionary model linking niche-level dynamics, transitions in single systems and ‘great surges of development’, as conceptualized by Schot and Kanger (2018) [1]. For this purpose, we conduct a case study on the historical evolution of mass production in the Transatlantic region from 1765 to 1972. Instead of focusing on dominant technologies or common practices the development of mass production is understood as the emergence of a meta-regime, i.e. a set of mutually aligned rules guiding production activities in multiple socio-technical systems. The results broadly confirm the overall model but also enable to extend the Deep Transitions framework by uncovering new mechanisms and patterns in the variation, diffusion and contestation of meta-regimes.