• IE interfaces
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• v.22 no.1
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• pp.73-84
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• 2009

In this paper, we propose a dispatching algorithm for constructing a Factory Operating System (FOS) which can operate semiconductor fabrication factories more efficiently and effectively. We first define ten dispatching criteria and propose two methods to apply the defined dispatching criteria sequentially and simultaneously (i.e. fixed dispatching architecture). However the fixed type methods cannot apply the criteria adaptively by considering changes in the semiconductor fabrication factories. To overcome this type of weakness, an adaptive dispatching architecture is proposed for applying the dispatching criteria dynamically based on the factory status. The status can be determined by combining evaluation results from the following three status criteria; target movement, workload balance, and utilization rate. Results from the shop floor in past few periods showed that the proposed methodology gives a good performance with respect to the productivity, workload balance, and machine utilization. We can expect that the proposed adaptive dispatching architecture will be used as a useful tool for operating semiconductor fabrication factories more efficiently and effectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.541-542
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• 2006

A micro-size caterpillar mixer has been recently used fur desktop chemical factory and so attractive due to small investment fund for arranging the factory and high efficiency by mixing in sub micro-level region. We report the fabrication of caterpillar mixer and its surface treatment for enhancement of mixing performance. We used the

• Journal of Korean Institute of Industrial Engineers
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• v.43 no.3
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• pp.229-237
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• 2017

Presented in this paper is a case study of constructing a smart factory for aircraft parts. The construction procedure involves four phases. First of all, its management goals are set, and layout design and simulation are carried out in the conceptual design phase. In the detail design phase, operating scenarios for each module are written out, and probable risks are analyzed by expert groups, and then requirements for developing equipments and subsystems are determined with consideration for element technologies and their integration schemes into the smart factory. In the fabrication and installation phase, system development, equipment fabrication and installation are proceeded in a separate manner, and then integrated together subsequently. In the operation and improvement phase, the factory is stabilized, sophisticated and improved constantly during real operation.

• Industrial Engineering and Management Systems
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• v.2 no.1
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• pp.9-27
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• 2003

In a wafer fabrication factory, the completion time of an order is affected by many factors related to the specifics of the order and the status of the system, so is difficult to predict precisely. The level of influence of each factor on the order completion time may also depend on the production system characteristics, such as the rules for releasing and dispatching. This paper presents a method to identify those factors that significantly impact upon the order completion time under various combinations of scheduling rules. Computer simulations and statistical analyses were used to develop effective due date assignment models for improving the due date related performances. The first step of this research was to select the releasing and dispatching rules from those that were cited so frequently in related wafer fabrication factory researches. Simulation and statistical analyses were combined to identify the critical factors for predicting order completion time under various combinations of scheduling rules. In each combination of scheduling rules, two efficient due date assignment models were established by using the regression method for accurately predicting the order due date. Two due date assignment models, called the significant factor prediction model (SFM) and the key factor prediction model (KFM), are proposed to empirically compare the due date assignment rules widely used in practice. The simulation results indicate that SFM and KFM are superior to the other due date assignment rules. The releasing rule, dispatching rule and due date assignment rule have significant impacts on the due date related performances, with larger improvements coming from due date assignment and dispatching rules than from releasing rules.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.939-954
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• 1995

We propose a policy for controlling the release of raw wafers into the semiconductor wafer fabrication lines. The proposed policy exploits up-to-date factory floor information gathered by tracking systems used to calculate the time and amount of a new release to minimize mean flow times and mean tardiness while maintaining the maximum output rates of the system. Extensive computer experiments show that the proposed policy results in significant improvements for the same output rates compared to existing release rules.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.996-999
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• 2008

Aspheric polymer lens fabrication using isothermal compression molding is presented in this paper. Due to increasing definition of an image sensor, higher precision is required by a lens which can be used as a part of an imageforming optical module. Injection molding is a factory standard method for a polymer optical lens. But achievable precision using injection molding has a formidable limitation due to the machining of complex mold structure and melting and cooling down a polymer melt under high pressure condition during forming process. To overcome the precision requirement and limitation using injection molding method, isothermal compression molding is applied to fabrication of a polymer optical lens. The fabrication condition is determined by numerical simulations of temperature distribution and given material properties. Under the found condition, the lens having a high precision can successfully be reproduced and does not show birefringence which results often in optical degradation.

• Journal of Korean Institute of Industrial Engineers
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• v.35 no.4
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• pp.266-279
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• 2009

This paper focuses on the problem of scheduling wafer lots with limited waiting times between pairs of consecutive operations in a semiconductor wafer fabrication facility. For the problem of minimizing total tardiness of orders, we develop a priority rule based scheduling method in which a scheduling decision for an operation is made based on the states of workstations for the operation and its successor or predecessor operation. To evaluate performance of the suggested scheduling method, we perform simulation experiments using real factory data as well as randomly generated data sets. Results of the simulation experiments show that the suggested method performs better than a method suggested in other research and the one that has been used in practice.

• Journal of the Korean housing association
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• v.18 no.4
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• pp.27-35
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• 2007

The use of light steel framing as a method of house construction has increased significantly throughout Japan, United States and Europe. Industrialized unit method are prevailing in developed countries. Unit modular house industry has supported an intensive technical development, and housing systems are now available, which are highly adaptable in form and use. Unit modular house have their own merits and demerits, but the more crucial aspect is that the constant design standard should be applied in each design procedure. It entails the necessity of industrial housing development on the open system basis. This paper describes the general forms of factory product system of unit modular housing system in Korea, United States, Japan. And this study attempts to propose the unit factory product system of which the rate of pre-fabrication is the biggest, that can cope with the demand of user on the basis of open-system.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.84.1-84
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• 2001

Funded by the Singapore National Science and Technology Board (NSTB), CAMTech is collaborating with a Singaporean research institute and two industry partners with the objective to improve electronics assembly processes. The goal of this project is to visualise the behaviour of an electronics assembly industry by simulating, visualising the discrete events of the entire manufacturing processes and observing the flow of materials, size of buffers, and line balancing. The traditional scenario - from the customer placing order for a product to delivery - goes through various phases including manufacturing the product. Several major electronics manufacturing stages can be addressed: fabrication, assembly ...

• Architectural research
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• v.15 no.3
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• pp.167-174
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• 2013

Due to increasing competition of construction companies, it is required to optimize the management of construction projects and "lean" concepts are rapidly spreaded in construction industry. Steel work accounts for a large proportion in construction work, and a variety of attempts to efficiently perform steel work has currently made. And since rebar (Engineer-to-Order) can be engineered through design once order is placed, it gives the great impact on construction, thus, entire management is required. The purpose of this study is to present the method to increase the efficiency of field processing method of steel work in terms of lean construction. Once we examine process of steel work and identify the flow, we would like to analyze which processes should be improved through value analysis approach and present the improvement plans. Also, this study examines cases of field processing and factory processing, and it identifies the waste factors in the procurement process. Finally, this study would like to present the result of analysis from the perspectives of value. The rebar delivery process is divided into several steps and the duration of every step is surveyed. Using duration data, VAT (Value added time) can be calculated for analyzing the efficiency of the process.