Hold Safety Inventory Before,At, or After the Fan‐Out Point?

We consider a product sold in multiple variants, each with uncertain demand, produced in a multi‐stage process from a standard (i.e., generic) sub‐assembly. The fan‐out point is defined as the last process stage at which outputs are generic (outputs at every subsequent stage are variant‐specific). Insights gained from an analytical study of the system are used to develop heuristics that determine the stage(s) at which safety inventory should be held. We offer a relatively‐simple heuristic that approaches globally‐optimal results even though it uses only two relatively‐local parameters. We call this the VAPT, or value‐added/processing time heuristic, because it determines whether a (local) stage should hold inventory based only on the value added at that local stage relative to its downstream stage, along with the processing time at that local stage relative to its downstream stage. Another key insight is that, contrary to possible intuition, safety inventory should not always be held at the fan‐out point, although a fan‐out point does hold inventory under a wider range of conditions. We also explore when postponement is most valuable and illustrate that postponement may often be less beneficial than suggested by Lee and Tang (1997).     

Changes in productivity of Spanish university libraries

This paper analyzes productivity growth, technical progress, and efficiency change in a sample of 34 Spanish university libraries between 2003 and 2007. Data envelopment analysis and a Malmquist index are combined with a bootstrap method to provide statistical inference estimators of individual productivity, technical progress, pure efficiency, and scale efficiency scores. To calculate productivity, a three-stage service model has been developed, examining productivity changes in the relationships between the libraries' basic inputs, intermediate outputs, and final outputs. The results indicate a growth in the productivity of the libraries (relationship between basic inputs and intermediate outputs) and in the productivity of the service (relationship between basic inputs and final outputs). The growth in productivity in both relationships is due to technical progress. If the variable representing the use of electronic information resources is removed from the final output, the result is a significant reduction in productivity.     

Manufacturing bill-of-material planning

The bill-of-material BOM in the machine tool industry takes two different forms in design and manufacturing functions: Engineering BOM E BOM , which is used by the design engineer to represent designed product structure; and manufacturing BOM M BOM , which is used by MRPII system for MRP explosion. The designer constructs the E BOM after the product has been designed. Next, the E BOM is transformed into the M BOM by considering assembly sequence and constraints. Constructing a M BOM simply involves compressing the E BOM into a three-level M BOM. Planning of a M BOM still depends primarily on the experience input of a manufacturing engineer and is performed manually. This trial and error and time consuming approach creates an inconsistent method for planning the M BOM. Therefore, in this study, a three-stage M BOM planning method is developed. Stage one plans the initial M BOM, stage two improves the M BOM and stage three tunes the M BOM. Concepts and algorithms of each stage are highlighted in this study. Moreover, an illustration is presented to demonstrate the feasibility of M BOM planning.     

Modelling and controlling product manufacturing systems using bond-graphs and state equations: Continuous systems and discrete systems which can be represented by continuous models

This paper presents an approach to the modelling and control phases involved in a cooperative process of design and management of the manufacturing systems. Modelling the evolution of the production flow, in the different sections of the system, is based upon the use of the bondgraph methodology in order to reach the state formalism which constitutes one of the modern representations of automation. The class of the systems studied ranges from continuous systems to discrete systems, which can be represented by a continuous approach according to the level of approximation required. The first part of this paper is dedicated to the development of generic models associated with the various basic entities of the manufacturing systems. Then, the bondgraph model of any system is obtained by assembling generic models in relation to the implementation of the means of the studied system, thus guaranteeing a representation which is quite close to the engineering sketches. Finally, switching to the state equation is performed systematically with the easiness provided by this formalism while taking into account the causality principle. An application, involving most of the elementary models developed, concludes the paper.     

Modeling market information processing in new product development: An empirical analysis

This research explores the antecedents and consequences of market information processing during the development process of new high-tech products. To this end, we develop and test a conceptual model for market information processing in three generic stages of the new product development (NPD) process (predevelopment, development and commercialization). In addition, we explore the relationships between market information processing, its antecedents, and product advantage and success. We test our model with responses from 166 NPD-managers in Dutch high-tech firms. The findings show that the market information processing variables are related differentially to new product outcomes, even when controlling for product advantage and product newness to the market. In addition, we found that companies can enhance market information processing for new high-tech products by influencing project priority and flexibility to new products, and by reducing interdepartmental conflict.     

Production control for just-in-time tool-and-die manufacturing

The strategy to implement production control varies in different types of manufacturing systems. We address the issue of production control in unit-based manufacturing systems where the production batch size of the final product is one or two, the product is custom designed and is made up of numerous individual components with similar process routeings lor special machine tools, turbines, boilers, tool-and-die, injection moulding equipment, custom fabrication, etc. We have developed algorithms to generate master production schedules in this particular domain of manufacturing systems using the concept of workgroups. We show how a Kanban-based JIT shopfloor control and purchasing system can be implemented in such systems in tandem with an inventory management system by utilizing the concept of demand lists. We also propose a model for practical implementation of production control in this domain. The methodology is illustrated at a tool-and-die plant where a CIM software is used to apply the JIT-based production control. Preliminary results show a significant reduction in lead times. We try to show the relationship between research and industrial applications of productions of production control and how to bridge the gap between them.     

Hypermaps: a representation of perceptions in conflicts

An approach to the modelling of conflicts, which is based upon personal construct psychology, is described. Use is made of the idea of cognitive mapping as a way of representing individual perceptions of a situation, and the relationships between the maps held by individuals who are in conflict are expressed by introducing the concept of ‘hypermaps’. The resulting implications for applications of the hypergame approach in practical studies are discussed     

Developing materials management

It is forecast that in the near future there may be a move towards the conscious development of materials management within manufacturing industry. This development will be based upon management recognition of the significance of materials management, combined with extensive pressure upon the costs and efficiency in the functions which make up the materials management systems. There will be a number of urgent motivating factors, ensuring that solutions are found to overcome any difficulties, and that change takes place to introduce the materials management concept. The final outcome is forecast to be an integration of the materials management function into one group; with the explicit task of, maintaining a constant flow of product, reducing costs where feasible, and improving relationships with both suppliers and other functions within the company.     

Organizational Learning,Innovation and Internationalization: A Complex System Model

Research on organizational learning, innovation and internationalization has traditionally linked these concepts through linear causality, by considering any one of them as the cause of another, an approach that might be considered contradictory and static. This paper aims to clarify these relationships and proposes a dynamic theoretical model that has mutual causality at its core and is based on ideas originating in complexity theory. The final model results from case studies of two clothing sector firms. The authors consider that the three concepts constitute a complex system and can adapt and transcend, as any alteration can take the system to the edge of chaos. Adaptability is fostered by concentration, improvement and discussion. Transcendence is fostered by attention, dialogue and inquiry. The different paces of the two case study companies led their systems to two different models: the incremental complex adaptive system model and the global complex generative system model. The incremental model is characterized by adaptive learning, incremental innovation and low internationalization; and the global system is characterized by generative learning, radical innovation and global internationalization. The paper ends with an exploration of the academic and management implications of the model.     

Leveraging Supply Chain Integration through Planning Comprehensiveness: An Organizational Information Processing Theory Perspective

This study extends prior research on supply chain planning and integration by examining the underlying capabilities by which firms exploit the information they gain from integration activities. We use organizational information processing theory (OIPT) to develop hypotheses that identify the comprehensiveness of an organization's supply chain planning capabilities as an important mediator in the relationship between its supply chain integration activities and its operational performance. Further, our interpretation of OIPT suggests that an organization's usage of technology‐enabled supply chain management systems (SCMS) moderates these effects. Using survey data from 445 global firms, we estimate the corresponding moderated‐mediation structural model. The results indicate that usage of SCMS enables organizations to better utilize the information they gain from external integration efforts (relationships with customers and suppliers), thus improving the comprehensiveness of their supply chain planning capabilities. In contrast, the use of SCMS appears to be a partial substitute for internal integration as a driver of planning comprehensiveness. Most importantly, the results suggest that planning comprehensiveness is a significant generative means by which integration and technology investments produce superior operational performance. These findings provide a richer and more theoretically grounded explanation of relationships between supply chain integration, supply chain planning, and operational performance.     

The Social Lives of Products: Analyzing Product Demography for Management Theory and Practice

Abstract

Despite the centrality of products in many strategic and managerial theoretical frameworks, little is known systematically about how and why specific products come and go from markets. We argue that narrowing this gap will likely enhance management theory, and we propose that research on product demography—the social lives of products—is a promising way to proceed. For organizing various theoretical ideas used in prior studies, we offer a classification framework. It defines four broad theoretical perspectives on product demography: market rationality, firm rationality, organizational bounded rationality, and institutional rationality. We also outline an approach to product demography that studies empirically the rates of product launch, growth, and withdrawal using stochastic models and data on all products ever appearing in bounded industrial domains. Finally, we discuss the challenges presented by such a fragmented approach to research on product demography and propose a generic research program intended to avoid stagnation.     

可变产能的按订单装配系统库存和生产决策研究

本文基于一个ATO 生产商的实践,考虑一个需求不确定并具有子装配件的单周期ATO 系统,为了应对较长的采购提前期和有限产能的挑战,生产商可以在得到确定的需求之前提前采购零件,装配子装配件以至于最终产品。由于产品物料清单结构中存在子装配件作为可选的中间件,因此完全使用零件和使用子装配件装配最终产品的不同,造成装配能力在时间上具有可变性。我们对此问题建立了利润最大化模型,分析在上述ATO 环境中的最优库存和生产决策。通过一系列最优解的性质,我们得到了该问题的有效解决方法。     

共性技术VS专用性技术:基于三阶段非合作博弈的供应商研发决策

本文针对面向多制造商的供应商研发决策问题,分别构造了供应商在选择共性技术和专用性技术研发决策情形下与两个制造商组成的三阶段非合作博弈模型,得到了供应商在这两种情形下各自的最优研发决策,通过对这两种最优决策情形下供应商最优研发程度比较,给出了这两种情形下供应商研发程度相等的条件和各自的占优区间。论文进一步讨论了供应商单位成本、制造商单位成本、最终产品替代率、单位研发成本变动对这两种情形下供应商最优研发决策的影响,并给出了相应的数值解,表明采用不同技术研发决策时供应商最优研发程度与制造商单位成本存在显著差异,即:采用共技术性研发决策时,与两个制造商单位成本负相关;采用专用性技术研发决策时,与面向专用性的制造商单位成本正相关,无专用性面向的制造商单位成本负相关。     

New views and visions on product structures

Abstract

The paper deals with different viewpoints in product structuring knowledge. Special interest is paid to a new viewpoint called control structure. The necessity for such a concept is based on the penetration of product oriented manufacturing systems (factories, workshops and cells) together with the related distribution of production management decision making. Control structure is an aggregated control oriented viewpoint on the product structure hiding the details of the work operations and materials requirements at the lower levels of decision making. Thus control structures are also intended for the integration and loosely coupled co-ordination of control units. The paper also strongly advocates the application of interactive graphics in the manipulation of product structure information. A practical system developed is demonstrated as a vehicle for implementing the concepts introduced.     

Development of sustainable platform for modular product family: a case study

Abstract

Defining product platform architecture is a critical issue to design and develop product variants. Different factors are highly dependent on the architecture type, such as number of variants, to measure modularity level, component commonality, market demand, etc. It is directly related to manage product portfolios and setting up business plan of a company. Before defining a product platform, whether it is modular or integral product designers need to follow specific design guidelines and checklists. This research mainly focuses on to define the platform architecture as well as provides necessary design guidelines and checklists for the product designers. It also highlights an example product of a case company with the objective to clarify/validate the proposed product design approach. In conclusion, this paper outlines the findings from this research and proposed some critical questions need to be answered within the scope of future research potentials.     

Investigating the effect of product variants,and demand distributions on the optimal demand supply network setup

In today's marketplace, consumers are looking for product variety and low prices. In this paper, we investigate how product variation and demand distributions affect demand supply network optimality in a real-life based setting. The research methodology was based on a novel Petri net formulation, which employs reachability analysis to demand supply network optimisation. We found that in our case study localised final assembly is justified with one or two product variants, but a centralised production should be favoured with three or more product variants. We also noted the sensitivity of this result to transport cost/inventory carrying cost tradeoff.     

Distributing a Product Line in a Decentralized Supply Chain

Although there is a rich literature on single product distribution in decentralized supply chains, the incentive problems that arise in distributing a product line have largely not been investigated. In practice, most manufacturers distribute a line of products with different features and qualities and not just a single product. Consider a manufacturer who distributes a product line through competing downstream retailers. In this setting, we investigate how and why the retailers' price and inventory decisions deviate from the centrally optimal decisions. Due to substitution between different product variants, as well as between different retailers, the incentive problems associated with distributing a product line are more complicated than that of distributing a single product. We characterize retailers' incentive distortions under a residual‐claimancy contract, and construct contracts that achieve channel coordination. We show that retail price floors or inventory buybacks, appropriately tailored to each product variant, are among the contracts that can achieve coordination. Using numerical simulations, we demonstrate how the optimal contract terms (such as wholesale prices and buyback prices) for each variant are influenced by the parameters of an underlying consumer choice model.     

基于BOM/Petri网的业务过程工作流模型的设计与实现

基于BOM /Petri的建模方法在生产制造领域得到了广泛的应用和发展。业务过程的管理与生产制造过程有着许多相似之处,本文将生产制造过程BOM和Petri网技术应用于工作流建模,给出了定义和分析方法,对工作流的动态建模进行了论证。最合结合实例实现了计算机的模拟仿真。     

Quality versus variance: a plea for a different focus and terminology

Much has been written about quality assurance in medical practice over the past 15 years. Medicine suddenly found itself trying to design systems that ensured that medicine was being practiced according to standards of quality when it had neither a definition of its product nor defined standards of practice. Consequently, early quality assurance programs focused primarily on documentation of patient care. As the process matured, it evolved to generic screens, with tolerances and outliers. The theory was that the quality of medical care was enhanced by physicians who practiced within often artificially established norms and was diminished by physicians who practiced outside those same norms. It was much like saying that the quality of manufacturing a new car could be improved by reducing all systems down to one of closely standardizing, observing, and documenting how each individual assembly worker put on a lock nut and then holding each worker independently accountable for the final quality of the care. Physicians felt they were being held responsible for conforming to a rigid set of poorly designed and retrospectively applied standards. Moreover, they were held accountable for applying those standards to all practice situations. Understandably, physicians felt at the mercy of nonphysician quality assurance "detectives" in hospitals and became increasingly suspicious of nurses and administrators, who were perceived as abusing the system at the expense of the physicians. Because of these inadequacies of the earlier quality assurance programs, paranoia among physicians about the quality assurance process remains rampant today. The use of blind outcome scores and practice patterns in credentialing and the reporting of these data to databanks have reinforced the paranoia.(ABSTRACT TRUNCATED AT 250 WORDS)     

Drivers and Performance Outcomes of Supplier Innovation Generation in Customer–Supplier Relationships: The Role of Power‐Dependence

While innovations generated by supply channel relationships, as opposed to individual partners, play an increasingly important role in the success of all supply chain partners, there has been a dearth of research in the literature on how supply chain relationships cultivate the process of such innovation generation. We explore supplier market knowledge acquisition, relationship learning, systems collaboration, and technological uncertainty as antecedents of supplier innovation generation, which is in turn hypothesized to positively affect the relationship performance of the supplier. Furthermore, supplier dependence on the buyer is investigated as a moderator of the effects of such antecedents on supplier innovation generation. Empirical tests, which used a sample of 236 Taiwanese executives, supported most of the hypotheses, and some implications of the results are discussed.