Valuation of expansion flexibility in flexible manufacturing system investments using sequential exchange options

In this paper, a valuation approach that modifies traditional discounted cash flow (DCF) methodology is presented to incorporate the option premium of expansion flexibility while evaluating a flexible manufacturing system investment. Expansion flexibility allows for changing the production capacity in response to deviations in demand, while disregarding the assumption that management makes an irrevocable decision based on its future market expectations. Expansion flexibility provides a key strategic advantage by avoiding the large financial commitment at the initial investment stage and enabling investment in a phased manner according to the changes in market conditions. The aim of this paper is to present a thorough valuation methodology that accounts for both the benefits of keeping the option to expand alive and the loss of market share to competing firms if the expansion investment were delayed. In this paper, the value of expansion flexibility is computed using sequential exchange options. The proposed method employs an analytic approximation scheme for valuing American exchange options on dividend-paying assets. A numerical example demonstrates the application of the valuation framework. The options approach that incorporates the expansion flexibility option into the analysis results in a higher value than the standard DCF approach, which ignores the value of the option to expand. We also perform sensitivity analyses to see whether the expansion option increases in value in cases of high uncertainty where management can respond flexibly to new market information, and where the investment analysis ignoring flexibility yields a marginally positive net present value. The results of the proposed valuation framework are presented in comparison with a previous model that ignores the opportunity cost of delaying expansion investment.     

On the lower bound of monitor solutions of maximally permissive supervisors for a subclass α-S3PR of flexible manufacturing systems

Recently, a novel and computationally efficient method – based on a vector covering approach – to design optimal control places and an iteration approach that computes the reachability graph to obtain a maximally permissive liveness enforcing supervisor for FMS (flexible manufacturing systems) have been reported. However, it is unclear as to the relationship between the structure of the net and the minimal number of monitors required. This paper develops a theory to show that the minimal number of monitors required cannot be less than that of basic siphons in α-S³PR (systems of simple sequential processes with resources). This confirms that two of the three controlled systems by Chen et al. are of a minimal monitor configuration since they belong to α-S³PR and their number in each example equals that of basic siphons.     

Customer order management in service oriented holonic manufacturing

One of the most important problems when considering the design of manufacturing systems based on SOA paradigms is the integration of shop floor devices in the business processes at the enterprise level. This paper presents the design and implementation of the Customer Order Management (COM) module based on SOA architecture in the context of holonic manufacturing systems. The COM module is integrating with SOA enabled shop floor devices using industry standards. The implementation leverages a multi agent system suited for industrial applications integrated in a SOA environment capable of dynamic BPEL workflow generation and execution. The prototype consists in a SCA application for core COM module functionality and an extension for NetLogo MAS platform for SOA integration. The COM module interacts with the MES layer using real time events handled by the BPEL process implementation in the execution stage. A web based portal frontend for the COM module has been developed to allow real time tracking of customer orders, providing data about product batch execution and individual progress of each product on the production line.     

Design strategy for reducing manufacturing and assembly complexity of air-breathing Proton Exchange Membrane Fuel Cells (PEMFC)

Conventional flat plate Proton Exchange Membrane fuel cell (PEMFC) designs have been under investigation for the last five decades with the majority of the research being conducted in fluid dynamics of the reactants, membrane chemistry, thermal characteristics, stacking, and electrical properties. By rigidly adhering to design characteristics and material choices (graphite flow plates and metal end plates), conventional fuel cell designs have become bulky, fastener intense designs that have a high degree of manufacturing and assembly complexity. The department of energy has recognized the need for economical and efficient manufacturing practices to further the market penetration and end user adoption of fuel cells. Therefore this paper analyzes air-breathing PEMFC's from the perspective of reducing manufacturing complexity, assembly complexity, and costs. Areas of complexity like the flow plates, end plates, sealing methods have been reassessed and this paper proposes alternatives to component functions, and the commonly employed materials along with an alternate assembly strategy. Prototypes built using the new design strategy achieved about 90% reduction in weight and number of components while enjoying an 80% reduction in costs. The new prototypes also possess a superior form factor, along with a 10-fold increase in power density as compared to conventional designs.     

Homogenization of material properties in additively manufactured structures

Additive manufacturing transforms material into three-dimensional parts incrementally, layer by layer or path by path. Subject to the build direction and machine resolution, an additively manufactured part deviates from its design model in terms of both geometry and mechanical performance. In particular, the material inside the fabricated part often exhibits spatially varying material distribution (heterogeneity) and direction dependent behavior (anisotropy), indicating that the design model is no longer a suitable surrogate to consistently estimate the mechanical performance of the printed component.We propose a new two-stage approach to modeling and estimating effective elastic properties of parts fabricated by fused deposition modeling (FDM) process. First, we construct an implicit representation of an effective mesoscale geometry–material model of the printed structure that captures the details of the particular process and published material information. This representation of mesoscale geometry and material of the printed structure is then homogenized at macro scale through a solution of an integral equation formulated using Green’s function. We show that the integral equation can be converted into a system of linear equations that is symmetric and positive definite and can be solved efficiently using conjugate gradient method and Fourier transform. The computed homogenized properties are validated by both finite element method and experiment results. The proposed two-stage approach can be used to estimate other effective material properties in a variety of additive manufacturing processes, whenever a similar effective mesoscale geometry–material model can be constructed.     

Planning and Sequencing Heuristics for Feature-Based Control of Holonic Machining Equipment

The intelligent manufacturing system program was proposed by Japan in 1989. Five participating regions—Australia, Canada, the European Community, Japan, and the United States—currently are involved in developing 21st century manufacturing technology through an investment of US $1.2 billion over 10 years. Korea joined the program and will start work on one of the six ongoing projects, holonic manufacturing systems (HMSs). The objective of the paper is to develop the control architecture of the holonic machining unit (HMU) for construction of the HMSs and to present some planning and sequencing heuristics for feature-based control of the HMU. Further, the paper provides the HMU's functionality using the IDEF0 function modeling method. The basic operation of the decision maker among the HMU's functions is to determine an efficient feature sequence in real time from the nonlinear feature graph used to represent a process plan. To this end, two methodologies are applied sequentially to managing a nonlinear process plan: removal of the OR nodes and then grouping and sequencing the features in the feature graph. Markov chain theory is used to compute the path preference indicator for removing the OR nodes, that is, for selecting the best path among those surrounded by OR nodes. The resulting graph is the AND graph, from which the feature type nodes are formed into sequenced groups. The CNC codes associated with the features in each group are combined and downloaded to the CNC machine. The development of the methodologies can help manufacturers efficiently cope with unexpected failures encountered during computer-automated machining.     

Zn-5%Al RE合金镀液的浸润性及其对表面质量的影响

从表面浸润的基本原理出发，分析了Ｚｎ ５％ Ａｌ ＲＥ合金镀液的浸润性。采用预先合金化的含稀土母合金、洁净的前处理、高效的助镀剂是提高浸润性消除光斑缺陷的必要条件；合金镀液的成分、温度、表面氧化状况也均会对浸润性产生很大的影响。必须严格控制工艺参数，精心操作，科学管理，才能获得好的表面质量     

Enabling multi-use, multi-tool models of manufacturing systems through an experimental frame expert system

A significant shortcoming of traditional modeling methodologies is the limited access they provide for decision-makers who are not modeling specialists. This paper presents an expert system approach to address this shortcoming. An expert system called the experimental frame expert system (EFES) was developed for this purpose within an advanced modeling environment for manufacturing systems. EFES reduces the dependence upon modeling specialists, and thus, makes models, both analytical and simulation, more accessible to decision-makers. This is accomplished by using two knowledge bases, one related to the manufacturing system specific symptoms and problems, and the other to system analysis and optimization tools. This paper presents the dissertation research effort that led to development of these two knowledge bases as well as the EFES framework within the advanced modeling environment.     

A virtual factory based approach to on-line simulation and scheduling for an FMS and a case study

The recent years have witnessed a revolution in computing capabilities. At the same time, modern manufacturing systems are becoming increasingly complex and capital-intensive. Here, we propose a virtual factory wherein an efficient prototyping testbed will be provided. It will be possible to develop detailed models to support system design and operation, to test different system configurations. Besides, It will be possible to manipulate all system features which impact performance, and to see the results of these manipulations, all without disrupting the actual system. This paper is one among very few that tries to represent the virtual factory in an analytic form so that many existing mathematical analyses can be applied. New pseudo resources can be added to form a new virtual environment, and control policy designed by engineers will be evaluated before being issued. Since a state-transition sequence of the virtual factory from the initial state to the final state can be seen as a schedule of the modeled system. An effective schedule of the processing can be obtained by using an A* based search algorithm, namely, Limited-Expansion A algorithm.     

先进电子制造技术的发展

依据先进制造技术的特点，系统论述先进电子制造技术，探讨在现代大制造环境下所涉及的电子设计技术和电子制造技术的等相关理论、方法、技术和最新发展。