Scheduling algorithms for computer-aided line balancing in printed circuit board assembly

Generalized flexible flow line (GFFL) is a scheduling environment comprising several machine banks which the products visit in the same order but can skip some machine banks. The type of machines in a bank can differ but they are suitable for performing the same manufacturing tasks. To change one product to another demands a set-up operation of the machine. This paper describes several scheduling algorithms for the GFFL problem. The overall structure of these algorithms is similar, consisting of machine allocation and sequencing phases. The algorithms have been integrated into an interactive production scheduling system for electronics assembly. Sample cases are used to illustrate the operation of the system in practice.     

On vendor part delivery dates in a stochastic assembly system

This paper describes the development of a model for the determination of optimal mean part delivery dates in a stochastic assembly system for the objective of minimizing the expected cost of subassembly and part inventory. Parts are assembled at each station to a subassembly. The part delivery and processing times at assembly stations follow known probability distributions. An approximate solution technique based on the optimization of individual stations in isolation is developed. The approximation applies a correction factor, as a function of the variability in part delivery and processing time, cost parameters and number of stations, to the decisions from the single station solutions to compensate for interdependence between stations. Results indicate that this is an effective approach and yields good near-optimal solutions with very little computational effort. Insights regarding the effect of the type of distribution used, random processing times, variance of the distribution used and cost parameter values on part delivery dates are also reported.     

Line balance analyses for system assembly lines in an electronic plant

This research analysed and optimised the assembly line balance of notebook computer system production lines in a major computer plant. The research developed a mathematical model for balancing assembly lines of a specific notebook computer system. Precedence relationship charts were created to enforce the required sequences and ILOG CPLEX software was used to obtain the optimal solution of the task assignments to the workstations. The new task assignments were simulated to verify the improvement recommendations and predict the potential benefits.The estimated improvements include: (1) 5.9% increase in average daily production; (2) 29% decrease in average daily WIP; (3) 67.9% reduction in cycle time; (4) 16.7% reduction in operator headcount over the whole system assembly area. The contributions of this research include: (1) Establishing line balancing mathematical model suitable for notebook computer factories; (2) Optimising the system assembly lines for the subject company; (3) Transferring the line balance modelling and optimisation techniques for company use.     

准时生产方式下混流装配线的调度问题

混流装配线的调度问题是 JIT生产方式中的一个重要问题 .本文建立了多级混流装配线的调度模型 ,其目标是使不同生产级上各零部件的消耗量尽可能保持均匀 ,并用遗传算法和模拟退火进行求解 .试验表明 :遗传算法和模拟退火算法的求解质量比“目标追随法”有所提高     

Multiple criteria approach for solving feeder assignment and assembly sequence problem in PCB assembly

The feeder assignment and assembly sequence problem in printed circuit board (PCB) assembly with the twin objectives of minimizing magazine travel time and minimizing board travel time is presented in this study. The problem uses Dynamic Pick-and-Place (DPP) model where robot arm, board and magazine move together with different speeds based on relative coordinates between consecutive assembled points. The difficulty of the problem is that the feeder assignment depends on assembly sequence and vice versa. A new approach is proposed to improve the existing approaches. The trade-off between two strategies, assembly by area and assembly by component types, can give better results. The numerical experiments proved the efficiency of the new algorithm.     

A multiobjective model and evolutionary algorithms for robust time and space assembly line balancing under uncertain demand

Changes in demand when manufacturing different products require an optimization model that includes robustness in its definition and methods to deal with it. In this work we propose the r-TSALBP, a multiobjective model for assembly line balancing to search for the most robust line configurations when demand changes. The robust model definition considers a set of demand scenarios and presents temporal and spatial overloads of the stations in the assembly line of the products to be assembled. We present two multiobjective evolutionary algorithms to deal with one of the r-TSALBP variants. The first algorithm uses an additional objective to evaluate the robustness of the solutions. The second algorithm employs a novel adaptive method to evolve separate populations of robust and non-robust solutions during the search. Results show the improvements of using robustness information during the search and the outstanding behavior of the adaptive evolutionary algorithm for solving the problem. Finally, we analyze the managerial impacts of considering the r-TSALBP model for the different organization departments by exploiting the values of the robustness metrics.     

The effects of learning and forgetting on the optimal lot size quantity of intermittent production runs

This paper studies the effects of learning and forgetting on the production lot size problem with infinite and finite planning horizons. It is assumed that the determination of the economic manufactured quantity (EMQ) in the succeeding production run is dependent on: (1) the maximum inventory accumulated prior to interruption; (2) the length of the interruption period which incurs total forgetting; and (3) the level of experience in equivalent units remembered at the start-up of the next production run. The optimum operating inventory doctrines is obtained by trading off procurement cost per unit time and the inventory carrying cost per unit time, so that their sum will be a minimum. A numerical example is presented to demonstrate the application of learning and forgetting to the determination of the EMQ.     

Efficient flow control of jobs in assembly lines

This paper addresses the issues of efficient flow control techniques for jobs in assembly lines. We propose a queuing theoretic approach for efficient flow control of jobs. An assembly line performance measure (ALPM) is used as the measure of performance for each assembly line and is denned as the ratio of throughput to total average delay of an assembly line (AL). A performance product criterion (PPC) is used as the performance measure of a cluster of ALs. It is shown that the performance product criterion has a unique maximum in throughput space. Two algorithms are presented to find the maximum of the performance product criterion in two different cases of assembly line environment. In the first algorithm, we attempt to maximize the performance product criterion with respect to the throughputs of the assembly lines in the entire throughput space. The second algorithm maximizes the performance product criterion when the sum of the throughputs of the ALs is fixed. Numerical examples are given as illustrations of the algorithms.     

An investigation of order release and flow time allowance policies for assembly job shops

The effects of a number of essentially different work order release and flow time allowance policies on the assembly order flow times and assembly order due date performance are investigated. Work orders within an assembly order have different routing length. The assembly order flow time is the time that elapses between the release of the first work order and the completion of the last work order of the assembly order. The timing of the release of work orders, and the distribution of the flow time allowance over the work orders in an assembly order were varied, and used systematic computer simulation to investigate the effects on performance. The results show that the best performance is obtained with simultaneous work order release, an average operation flow time allowance equal to the average operation waiting time and equalized flow time allowances per work order in an assembly order.     

Learning in and from projects: the learning modes and a learning capability model

Abstract

The notion of ‘project delivery’ is well embedded in and across the management and organizational sciences literature – generating a narrative that reflects and recognizes the instrumental nature of projects and programmes in strategy execution. Project management, as a distinct and well-established body of research enquiry, has increasingly sought to focus our attention on the impacts of complexity, risk and uncertainty in projects; the corollary being a desideratum to strengthen our theoretical understanding of how insight and learning from projects may influence improvements to organizational efficiency. The wider literature suggests that organizational learning remains a challenging proposition, particularly in the context of organizations operating in environments of high complexity. In this paper, we enhance the conversation on organizational learning through a series of case studies, generating evidence of thirteen ‘learning modes’. The paper proposes that mature organizations tend to exhibit a greater number of learning modes and that there is a tendency to capture and socialize knowledge with a greater emphasis on the context of the learning situation rather than the learning artefact in isolation. The empirical evidence gathered in this paper forms the basis of a capability model, characterized by the thirteen modes of learning. The model intimates that learning occurs, and is more effective, when knowledge and information are enacted in practice through the learning modes which form a nucleus of the organizational learning capability. The research concludes with a 'call to action' that emphasizes the strategic importance of learning practices and routines in project oriented-organizations.     

Single-machine scheduling problems with the effects of learning and deterioration

In this paper, we consider the single-machine scheduling problems with the effects of learning and deterioration. By the effects of learning and deterioration, we mean that job processing times are defined by functions of their starting times and positions in the sequence. It is shown that even with the introduction of learning effect and deteriorating jobs to job processing times, single-machine makespan and sum of completion times (square) minimization problems remain polynomially solvable, respectively. But for the following objective functions: the weighted sum of completion times and the maximum lateness, this paper proves that the WSPT rule and the EDD rule can construct the optimal sequence under some special cases, respectively.     

战略导向、组织学习对产品创新的影响研究

本文对战略导向影响产品创新的路径进行了研究,发现不同战略导向对学习活动有不同的选择倾向,而不同类型的学习活动也会对产品创新产生不同的影响。本研究不仅弥补了应用性学习与探索性学习研究的不足,也有助于企业引导和利用组织学习来提高产品创新水平,为管理实践提供理论参考。     

Postponement implementation in integrated production and inventory plan under deterioration effects: a case study of a juice producer with limited storage capacity

Abstract

The aim of this study is to develop a production and inventory plan for a fresh apple juice producer. During harvest season, the producer extracts premium juice from freshly picked apples and keeps an inventory of these premium apples in his temperature-controlled storage facility. The producer extracts also regular juice from regular apples purchased from third-party storages. To satisfy future demand, the producer carries inventories of juice and apple. The levels of apple inventories are constrained by the producer’s limited storage space, but he can replenish regular apples. To assist the producer in facing demand uncertainty and deterioration of apples, we develop a production and inventory plan that incorporates postponement to mitigate demand uncertainty. As postponement decisions are shaped by the cost structure of inventories, we integrate in one model the postponement decisions and the deterioration mitigation decisions that can alter the inventory costs. We build multi-period stochastic programming with recourse model to determine juice batch sizes and apple inventories that maximize the producer’s expected profit. The optimal solution illustrates the use of time and form postponements. We discuss the interactions between postponement implementation and decisions to mitigate apples deterioration. We compare the production and inventory plans with and without postponement and with and without apple deterioration. We also present sensitivity analyses for the plan under varying inventory cost and storage space.     

Re-engineering high risk, high complexity industries through multiple level technological learning A case study of the world nuclear power industry

Applying lessons learned at the national, the utility, and the plant level, from selected segments of the world-wide nuclear power industry, might facilitate an environmentally acceptable renaissance of the U.S. nuclear power industry through re-engineering it. Elements of this learning from experience process can be found: (a) at the national level in Europe, Japan, and the U.S., (b) at the utility level in two New York State nuclear power utilities, Niagara Mohawk and New York Power Authority, the Tenessee Valley Authority, and Duke Power and Light in the U.S., in Ontario Hydro in Canada, and in the Electricité de France (EdF) in France, and (c) at the plant level in several of these utilities. At the core of all the continuous quality improvement and re-engineering programs, lies this twofold mission: (a) to insulate society from foreseeable and unacceptably high environmental risks, and (b) to continuously improve the design and management of nuclear technology (including nuclear waste management and environmental risk management systems) by learning, learning how to learn, and learning to learn-how-to-learn, both explicitly and tacitly, through feedback from individual and organizational experience.     

Fuzzy multi-attribute decision-making for grouping of electronic components in process planning

The grouping of objects problem has a wide-range of applications in industry. In electronic assembly planning, grouping components play an important role as they can reduce drastically the number of possible sequences of operations. This paper considers the grouping problem of electronic component families based on their multiple attributes. The difficulty lies with the conflict of criteria when selecting a certain component into a group. In order to overcome this difficulty, the proposed approach introduces the concept of fuzziness, which expresses the degree of concordance on the decision. An example of classification electronic components is presented to illustrate the proposed method.     

正负试看效应下网络视频平台的内容提供策略选择

基于网络视频的消费行为特征,在正负试看效应下建立了考虑消费者学习成本和预期认知的网络视频平台收益模型,分析不同情况下的平台收益和策略选择。研究发现:当平台不提供免费试看时,若消费者学习成本较小,付费策略的收益大于免费策略的收益。当平台提供试看时,若学习成本较大,正负试看效应下平台提供试看的收益均大于不提供试看的收益。试看效应为正向时,若学习成本较小,平台应该选择付费策略;若学习成本较大,平台应选择试看策略;若学习成本适中且预期认知较高,平台应选择免费策略。试看效应为负向时,无论消费者预期认知和学习成本如何变化,平台均不会选择试看策略,但提供试看不一定为最劣选择。此外,当消费者预期认知较低且学习成本较小时,负向试看效应下的平台收益大于正向试看效应下的平台收益。     

Learning strategies of workers in the knowledge-creating company

This study presents a critical examination of Nonaka and Takeuchi's theory about knowledge-creating companies (1995), taken as one example of contemporary management theories concerning innovation and learning. Two main questions are investigated. First, how is the learning of workers organized in the knowledge creation theory? Second, how is their learning related to the work they perform? Answers to these questions are sought from case-study research into work-related learning projects (Poell 1998) and from theoretical notions about learning networks in various work types (Van der Krogt 1998). Our first conclusion is that Nonaka and Takeuchi seem to assume that workers will learn only within the boundaries set by management. They do not, however, take into account that workers organize a great deal of learning themselves, frequently irrespective of management expectations. Second, Nonaka and Takeuchi expect workers to learn according to rigid bureaucratic principles in a work context emphasizing innovation. The theory of knowledge creation does not show how these contrary principles might be successfully integrated.     

Development of simulation-based production execution system in a shipyard: a case study for a panel block assembly shop

The management of a panel block shop in a shipyard is a complex process that entails the largest amount of work and in which many decisions are involved. Shipbuilders have considered the process as a bottleneck since every panel for every ship must be processed through the shop. The objective of this research is to carry out a materials flow analysis to maximise process productivity and to place simulation optimisation technology in the hands of decision makers, such as production planners and supervisors. In this article, a production execution planning system is proposed for panel block operations utilising discrete-event simulation and simulated annealing. The simulation model was validated using a real production scenario and the comparison showed a very favourable agreement between the actual panel shop and the simulation model. The proposed system supports production planners by general dispatching rules and optimisation to make better scheduling decisions on the shop floor. The system will provide a complete schedule that is at least as clear and accurate as any schedule currently obtained.     

基于产业结构优化的经济增长方式转变——作用机理及其测度

经济增长方式转变是由高级生产要素的生产和流动所引致的国民经济中一系列生产函数配置方式由低级向高级的动态演变过程,产业结构优化体现在发生配置方式变革的产业内部和产业之间各种生产函数的结构性调整,两者可归结为要素配置结构变革在不同层面上的体现。以要素配置结构变革为桥梁,从产业结构合理化和高级化角度研究经济增长方式转变的机理,并对大道定理进行拓展,认为产业结构优化与经济增长方式转变之间相互推动,使经济增长过程表现出阶段性的动态演变路径。基于此,从产业结构的微观要素配置层面和宏观动态演进层面构建判别经济增长方式转变的衡量体系,并指出经济增长方式转变取决于政府诱导性结构变迁手段和市场内生性结构变迁动力间的兼容程度。     

地方高校本科生学习状态自评量表的设计研究

目的:编制适用于本科生学习状态的测评量表,并检验其效度和信度。方法:在文献研究与理论研究的基础上,运用头脑风暴法、深度访谈法,结合多年的教学经验设计初始量表。采用分层随机整群抽样的方法对海南省某地方高校的本科生进行现场匿名调查。采用临界比率法、相关分析对量表条目的区分度进行分析;采用探索性因子分析对量表进行效度检验;采用内部一致性信度与分半信度对量表进行信度检验。结果:共发放652份问卷,回收有效问卷608份,有效问卷回收率为93.25%。经探索性因子分析,最终提取了5个因子,共包含28个条目,能解释总方差的56.99%。该量表的总Cronbach'sα系数为0.962,总分半信度为0.868。各维度的α系数均在0.8以上,分半信度均在0.74以上。结论:设计的本科生学习状态测评量表具有良好的效度和信度,能有效测量海南省某高校的本科生学习状态,也能为其他高校测量本科生学习状态提供参考依据。