Threshold-based method for elevating the system's constraint under theory of constraints

The principal tenet of theory of constraints (TOC) is that there is at least one constraint in each system that limits the ability of achieving higher levels of performance relative to its goal. Maximum utilisation of the constraint leads to maximum output of the system. However, activation of a non-constraint resource at 100% of its capacity does not increase output. Therefore, some resources are not fully utilised. In this paper, the authors use the left capacity of a non-constraint resource (NC) to elevate the system's constraint. It is assumed that the capacity-constrained resource (CCR) is a continuous time Markov process having a two-dimensional state space. The work in the NC is interruptible, allowing a worker in the NC to switch to CCR. The switch from NC to CCR would occur when the queue of waiting parts in the CCR becomes ‘too long’ and vice versa, when there are few parts in the CCR. Returning to the NC from the CCR may require some ‘re-orientation time’ on the part of the switched worker. The goal is to find the maximum output of CCR subject to the time-average number of workers in the NC must be greater than a pre-specified value.     

碳氢制冷剂应用于汽车空调的可行性分析

本文分析了碳氢制冷剂作为汽车空调制冷工质的优势和汽车空调中使用碳氢制冷剂的危险性,综合国内外的研究,得出汽车空调中使用碳氢制冷剂有很高的安全性,对比了R290、R600a的混合物和R12的性能,从理论上验证了用碳氢制冷剂替代R12作为汽车空调循环工质的可行性,计算了一些品牌汽车的空调系统碳氢制冷剂的理论充灌量,为碳氢制冷剂在汽车空调中的应用提供了参考.     

MCT的概念及其在工厂管理中的应用

介绍了生产制造击期的概念及其计算方法，讨论了在工厂管理中如何应用ＭＣＴ。     

聚苯胺的合成优化及其电化学性能研究

运用正交试验法研究了温度、酸浓度、氧化剂配比、金属离子掺杂对乳液聚合聚苯胺性能的影响,结果表明,反应最佳条件为NH4S2O8(m=1.5g):An=3:5、HCl浓度1.2mol/L、反应温度20℃、掺杂离子为Fe3+。不同条件下合成的掺杂态聚苯胺经红外、电导率测定以及循环性能测试,证明,掺杂聚苯胺具有较好的电化学性能。     

Closed-form analytical results for condition-based maintenance

Preventive maintenance is applied to improve the device availability or decrease the repair costs when the device failures are in deterioration (or aging) phase. Preventive maintenance can be made more efficient by periodic monitoring wherein the state of deterioration can be assessed. This leads to the notion of condition-based maintenance. In this paper, we study the condition-based maintenance, and derive closed-form expressions of system availability when the device undergoes both deterioration as well as Poisson type failures. These closed-form solutions enable us to find faster algorithms to determine the optimal inspection policy.     

生产系统业务和制造流程再造的层次化方法

运用约束理论的思想,结合Petri网建模工具,提出了一种生产系统再造的流程结构优化和瓶颈优化的层次化方法,并对如何运用时间Petri网模型寻找和消除约束进行了探讨.这一方法有助于有效确定再造的重点,明确再造范围,从而提高再造的成功率.最后介绍了这个方法在企业的应用.     

Achilles’ heel strategy: identifying and leveraging a competitor’s weakest point

Significant developments in military strategy over the past century have had little impact, if any, on business strategy. This article focuses on the military paradigm shift from brute-force frontal confrontation as practised in the First World War to shrewd identification of weaknesses in the adversary’s rear. To apply this insight in the business world, we present a methodology focusing on the weakest link: the Achilles’ heel. We apply this methodology in identifying the adversary’s Achilles’ heel and attacking it. We aim to avoid attacking the competitor’s front namely its products in the marketplace through painful head-to-head attrition price and advertising wars. Instead, we propose a new attack strategy – focusing on the adversary’s weakest link. The study integrates a new military insight, specifically from an approach called operational theory, with an insight from the theory of constraints. The sophistication of the Achilles’ heel strategy makes it particularly effective for small players – David competing with large Goliaths. We present a methodology: identifying the Achilles’ heel; deciding whether or not to attack it; and tailoring an Achilles’ heel strategy. The theory is illustrated by numerous business and military applications.     

Working time constraints in operational fixed job scheduling

In this study we consider the operational fixed job scheduling problem under working time limitations. The problem has several practical implications in both production and service operations; however the relevant research is scarce. We analyse pre-emptive and non pre-emptive versions of the problem and its special cases. We provide polynomial-time algorithms for some special cases. We show that the non pre-emptive jobs problem is strongly NP-hard, and propose a branch-and-bound algorithm that employs efficient bounding procedures and dominance properties. We conduct a numerical experiment to observe the effects of parameters on the quality of the solution. The results of our computational tests for the branch-and-bound algorithm reveal that our algorithm can solve the instances with up to 100 jobs in reasonable times. To the best of our knowledge our branch-and-bound algorithm is the first optimisation attempt to solve the problem.     

订单生产优先权的确定方法研究

订货型生产企业中,生产优先权的确定是制订生产排程的关键问题。约束理论、线性规划理论和层次分析法均从不同角度给出了确定优先权的原理和方法。以生产战略理论为指导,以上述理论与方法为基础,提出了确定生产优先权的新方法－－战略生产排程方式,并给出了应用实例。     

Theory of constraints: is it a theory and a good one?

In this study, we attempted to advance the academic dialogue towards establishing TOC as a formal operations management theory, so it can continue improving practice. We link the component parts of the TOC and map the theoretical arrangement to the consensual definitional components and properties of a theory. Also, we examine whether TOC satisfy the virtues of a good theory (uniqueness, parsimony, conservation, generalisability, fecundity, internal consistency, empirical riskiness, and abstraction). Consequently, a practical outcome of our study stems from demonstrating the utility of the goodness criteria as a useful instrument for examining future theories in the field of operations. From a practitioner's standpoint, by establishing a strong theoretical foundation for TOC, we assist managers deploying it to gain better understanding of TOC elements and ultimately avoid implementation failures. Also, we increase the credibility of TOC in the eyes of senior executives. The study concludes by sketching new avenues for future research that have industrial relevance for successful TOC implementation efforts.     

制约理论在管理会计中的应用一例

制约理论是当今美国和欧洲比较流行的一套管理哲理和持续改进方法。通过实际案例，根据Goldratt的5个关键步骤，找到系统的制约，利用开发和释放制约从而使系统的整体能力得以提高。     

基于TOC理论生产流程的改造

基于约束理论、生产作业与管理的原理对G公司生产流程进行分析,找出该企业生产流程中目前存在的问题,利用约束理论的相关知识与概念提出改善G公司生产流程基本途径.