Chiwoon Cho

A genetic algorithms simulation approach for the multi-attribute combinatorial dispatching decision problem

This paper presents a genetic algorithms (GA) simulation approach in solving a multi-attribute combinatorial dispatching (MACD) decision problem in a flow shop with multiple processors (FSMP) environment. The simulation is capable of modeling a non-linear and stochastic problem. GA are one of the commonly used metaheuristics and are a proven tool for solving complex optimization problems. The proposed GA simulation approach addresses a complex MACD problem. Its solution quality is illustrated by a case study from a multi-layer ceramic capacitor (MLCC) manufacturing plant. Because GA search results are often sensitive to the search parameters, this research optimized the GA parameters by using regression analysis. Empirical results showed that the GA simulation approach outperformed several commonly used dispatching rules. The improvements are ranging from 33% to 61%. On the other hand, the increased shop-floor-control complexity may hinder the implementation of the system. Finally, future research directions are discussed.

A study on process evaluation and selection model for business process management

Research highlights? We describe a business process evaluation model for BPM. ? A web-based business process evaluation system is also implemented. ? We demonstrate the applicability of fuzzy AHP and BSC in business process evaluation. Currently, BPM is considered as the suitable framework for todays process-centric trends and BPM may result in considerable rewards for companies adopting it. For successful BPM initiative, the selection of suitable processes for BPM is very important. However, it is difficult to evaluate systematically and reasonably business processes for enterprises that plan to introduce BPM. This paper describes a web-based business process evaluation model based on BSC and fuzzy AHP for BPM. A web-based business process evaluation system was implemented and it provides impartial and reasonable results to enterprises or concerned persons that have insufficient experience and knowledge about BPM. Thus, this paper demonstrates the applicability of fuzzy AHP and BSC concepts in business process evaluation and selection for BPM, and provides a systemic guidance in the decision-making process.

Design of a web-based integrated material handling system for manufacturing applications

This paper describes a Web-based system called DESIGNER for the design of integrated material handling systems in a manufacturing environment. DESIGNER models and automates the material handling system design process, including the selection of material handling equipment. For a given application, the system designs the material handling system through three phases. In phase I, the procedure finds the most appropriate material handling equipment type among the alternatives for each material flow link. Knowledge-based rules are employed to retrieve the alternatives for each material flow link. To consider and compare the alternatives, multiple design factors are considered. These factors include both quantitative and qualitative measures. The qualitative measures are converted to numerical measures using fuzzy logic. The concept of fuzzy logic is applied to the knowledge-based rules as sensitivity indices and to evaluation matrices used for the selection of the most suitable material handling equipment through a fuzzy linguistic approach. In phase II, the set of selected equipment for the flow links is checked against redundancy and excess capacity with the objective of minimizing total system cost and improving equipment utilization. In phase III, the set of material handling equipment selected is subjected to economic analysis and, when necessary, adjusted to satisfy budget constraints to ensure feasibility. Because the system developed is Web-based, it is widely accessible to users worldwide. The ease of accessibility will enhance its use by multiple users in the design of real life material handling scenarios.

Simulation study for a proposed segmented automated material handling system design for 300-mm semiconductor fabs

Abstract With the increase in the size and weight of 300-mm wafers, the factory area must be enlarged accordingly. Due to the flow of material over long distances, the elimination of manual wafer handling has become necessary. Consequently, an automated material handling system (AMHS) is required for 300-mm semiconductor manufacturing facilities. The design of an AMHS must not only be capable of meeting numerous complex material handling requirements, but it must also simplify control and reduce capacity loss. In this study, a segmented dual-track bidirectional loop (SDTBL) design for an AMHS is proposed. The configuration is based on a double-loop flow path structure that is divided into non-overlapping segments, each containing a certain number of vehicles operating in bidirectional mode. A transfer buffer is set to enable conversion between segments and connect each independent zone. This structure eliminates congestion and blocking without requiring additional investment by operating vehicles on mutually exclusive tracks. The segmentation strategies and steps for two scenarios are developed in this research, and a simulation is performed to evaluate the performance of each segmented strategy. The simulation results show that the proposed strategies can reduce the cycle time and increase stocker utilization by up to 55.55% and 39.39%, respectively, while the throughput remains the same. The proposed design has great potential for practical application.

Design of a BPR-Based information strategy planning (ISP) framework

In this paper we propose a BPR-based Information Strategy Planning (ISP) Framework, which aims to fully incorporate the BPR concept into ISP. Since business processes and information systems (IS) are tightly linked together, business processes need to be reengineered during information systems planning. Five sub-processes are defined in the framework – Business Strategy Analysis, Process Analysis and Redesign, IS Analysis and Modeling, Organization Analysis, and ROI (Return On Investment) Analysis and Integrated Execution Planning of IS. With this framework, it is expected that enterprises will be able to perform more effective, efficient, and strategic IS planning.

The use of a simulation, a hybrid Taguchi, and dual response surface methods in the automated material handling system tool-to-tool strategy for a 300-mm fab

With the increase in the size and weight of 300-mm wafers, manual handling has become difficult and automated material handling systems (AMHS) are necessary. The 300-mm fab requires only one type of vehicle and rail to connect all of the process resources, allowing vehicles to travel directly between intrabay and interbay systems. This type of transportation is a direct tool-to-tool transportation strategy. This paper aims to analyse the impact of direct tool-to-tool transportation. The present study used a discrete-event simulation to create a 300-mm semiconductor manufacturing flow and executed a factorial experiment of three factors based on uniform design, including the direct ratio, the stocker capacity and the number of machine load ports. Finally, using the dual-response surface method, the most important of the three factors and the best performance were determined. The results show promise for the proposed tool-to-tool transportation strategy in solving a practical application. [Received: 9 February 2010; Revised: 6 October 2010; Accepted: 17 November 2010]

Customer Oder Fulfillment Process Analysis with Process Mining: An Industrial Application in a Heavy Manufacturing Company

Under the pressure of the rapid change engendered by the fast growth of information and communication technologies, organizations are required to continuously enhance their business processes in order to defend their market position and maintain their competitive edge. To achieve this, process mining has emerged as a mean to analyze the behavior of companies by extracting process-oriented knowledge from event logs recorded in todays information systems. In this paper, we present an industrial application of process mining in a real customer order fulfillment process of a heavy manufacturing company. This process is characterized by a very long lead time. Event logs from the Shipbuilding Processing Plan Management System of the company are analyzed based on several process mining techniques. We have identified the real as-is process of the customer order fulfillment process and determined what makes this process spending too much time. The outcomes of this case study can be used by the company as a foundation to optimize and improve their processes.

The state-of-the-art of business process mining challenges

Business process mining is a new method that amalgamates business process modelling and analysis with data mining and machine learning techniques, whereby knowledge from event logs stored in todays information system is extracted to automatically construct business process models, identify bottlenecks, and improve the business processes. Since process mining has recently received attention among the research community, there are many challenges. The most important issues have been defined in the process mining manifesto. However, none of the published works investigated, or the defined challenges, have been solved and are still being encountered. Therefore, this paper provides a comprehensive and critical review of the literature in the context of process mining challenges. The contribution of this paper is to increase the maturity of the field of process mining by providing researchers with the state-of-the-art of the most important challenges of process mining.

Mathematical Problems in Emerging Manufacturing Systems Management

1 Institute of Manufacturing Information and Systems, National Cheng Kung University, Tainan 70101, Taiwan 2Department of Transportation and Logistics Management, National Chiao Tung University, Taipei 100, Taiwan 3Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hong Kong 4Department of Industrial Engineering, University of Ulsan, Ulsan 680-749, Republic of Korea 5Bristol Business School, University of the West of England, Bristol BS16 1QY, UK