• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.56-60
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• 1996

In most dynamic manufacturing environments today, systems and processes are constantly changing. Simulation tools are required that can accurately model the system in detail, but still be easy to use, and allow rapid model redevelopment to react quickly for system changes. An object-oriented simulation modeling environment is presented to provide flexible modeling capabilities for simulation. Also, when simulating an assembly system, a large number of factors must be considered. Because of such complexities, simulation has been used as the primary method in designing, planning and analyzing. In this paper, the dynamic manufacturing environment is discussed for the assembly system. Also, an application method of simulation tools is presented with the experimental data from the automobile manufacturing shop to improve the productivity effectively.

• Journal of the Korean Operations Research and Management Science Society
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• v.30 no.4
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• pp.15-25
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• 2005

As implied by the terms of IT productivity Paradox, measuring the Information technology contribution to economic performance has been one of the challenging issues to both policy makers and business professionals. As such, diverse attempts with sophisticate analyses have been reported in the literature to analyze the effect of IT contributions. In this paper, we follow Growth Accounting Method to measure the IT contribution effect to manufacturing firm's economic performance in Korea. Various regression methods and statistical analyses are applied with fourteen years of industry Panel data. Using the Cobb-Douglas function, time lag analysis is made to understand IT effect to economic growth. Instead of capturing data from individual firm, industry level data from the National Statistics Bureau is used for IT capital, non-IT capital, and so on. Statistical analysis following the panel unit test and Panel co-integration test was performed to reveal the exact effect of IT contribution to economic performance. Empirical testing results for non-stationary nature of IT investment effect are reported as well as IT contribution to manufacturing industry's economic performance.

• Journal of Korean Medical classics
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• v.26 no.2
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• pp.121-132
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• 2013

Objective : Bambusae Caulis in Liquamen has been used by East Asian doctors who approved efficient clinical effects of it since the early stage of medical history. It is commonly used for lifestyle related diseases including stroke in recent days thanks to the increasing number of manufacturers. However, products from pharmaceutical companies as well as food companies are not classified as Bambusae Caulis in Liquamen but Bamboo vinegar. This study aims to discern disparate manufacturing process. Methods : In this study, original texts were searched to corroborate the correct method to produce Bambusae Caulis in Liquamen. It is essential to inspect the original texts thoroughly in the course of modernizing traditional knowledge. Result : Discrimination between the two substances starts from manufacturing process; Bambusae Caulis in Liquamen is made under the temperature of less then $170^{\circ}C$, containing mild fragrance and sweet taste, and the Bamboo vinegar over $170^{\circ}C$ upto $400^{\circ}C$, carrying strong smoky scent and acidness. Although some researches show conforming clinical actions of both products, still there is a possibility that closer clinical study would reveal their discrepancy. Conclusion : Current use of Bambusae vinegar needs speculation. Authenticity in proper manufacturing process can be attained through passed-on medical texts.

• Journal of Applied Reliability
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• v.16 no.3
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• pp.245-253
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• 2016

Purpose: The purpose of this study is to measure the reliability of complex equipment. Reliability of product is one of the most important factor to achieve competitiveness in the market. While there were many researches for assessing the reliability on components and modules, research on quantitative assessment tool for equipment with many component was little because of equipment's complexity. Methods: In this article, we developed index to assess reliability management system by using IEC 60300 and Reliability Management Tool-kit. With MIR and BARS, we developed reliability index clauses relevant to reliability activities and found weight factor for each clause by survey on experts. Results: The results of this study were as follows; reliability index that can assess both management side and technology side of the company was developed. Conclusion: Using this index, we assessed the reliability of a manufacturing equipment and found out the current reliability level of the manufacturing equipment, and derived improvement points.

• Journal of Korean Society for Quality Management
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• v.41 no.1
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• pp.15-38
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• 2013

Purpose: This study is to search for the core factors of improving business performance of small and medium venture manufacturing company and to do an in-depth analysis of the relations with management performance through systematic approach and to provide implications of importance of the management for the improvement factors for the domestic small and medium venture manufacturing company. Methods: The data have been analyzed via the regression and path analysis using AMOS. Results: this study is absorptive capacity affects the business performance of manufacturing companies. absorptive capacity has the role of the parameters of the Quality Management System and business performance. Conclusion: This study suggests how to run absorptive capacity according to type of management performance, and how to enhance Quality Management System to efficiently promote absorptive capacity in order to grow of management performance. also, this study shows a way to enlarge the valuation standard for management and customer performance reflecting the growth potential of an enterprise in circumstance where the valuation standard focuses on financial performance.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.2
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• pp.166-173
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• 2015

Objectives: The purpose of this study was to evaluate cobalt concentrations in airborne inhalable, total and respirable dust from manufacturing industries using cobalt. Methods: To compare cobalt concentrations, three types of dust samplers(a 37mm closed cassette sampler, Institute of Occupational Medicine(IOM) sampler, and Aluminum cyclone sampler) were used. The analysis of cobalt concentrations was conducted using AAs based on the NIOSH 7300 method. Results: The geometric mean of cobalt concentration in total dust was $1.47{\mu}g/m^3$, and the rate of excess of the Korean Occupational Exposure Limit(KOEL) was 10.0%. The geometric mean concentrations of cobalt in super alloy manufacturing industries were higher than those in plating industries, and molding operations showed higher exposure levels to cobalt than did other operations. Conclusions: The rate of cobalt concentration in inhalable dust from super alloy manufacturing industries exceeding the Workplace Exposure Limit(WEL) as recommended by the Health & Safety Executive(HSE) was 7.1%, which means proper work environmental management is required through wet work environments. Given that molding operations had higher cobalt concentrations, it is necessary to apply measures such as local exhaust for reducing airborne dust in cobalt manufacture industries.

• Safety and Health at Work
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• v.5 no.2
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• pp.97-105
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• 2014

Background: Prolonged standing has been hypothesized as a vital contributor to discomfort and muscle fatigue in the workplace. The objective of this study was to develop a decision support system that could provide systematic analysis and solutions to minimize the discomfort and muscle fatigue associated with prolonged standing. Methods: The integration of object-oriented programming and a Model Oriented Simultaneous Engineering System were used to design the architecture of the decision support system. Results: Validation of the decision support system was carried out in two manufacturing companies. The validation process showed that the decision support system produced reliable results. Conclusion: The decision support system is a reliable advisory tool for providing analysis and solutions to problems related to the discomfort and muscle fatigue associated with prolonged standing. Further testing of the decision support system is suggested before it is used commercially.

• Elastomers and Composites
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• v.51 no.4
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• pp.301-307
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• 2016

Additive manufacturing (AM), so called 3D Printing is a new manufacturing process and is getting attraction from many industries. There are several methods of 3D printing. Among them fused deposition modeling (FDM) type is most widely used by reason of cheap maintenance, easy operation and variety of polymeric materials. Articles manufactured by 3D printing have weak deposition strength compared with conventionally manufactured products. Deposition strength of FDM type 3D printed article is highly dependent of deposition temperature. Subsequently the nozzle temperature in the FDM type 3D printing is very important and it is controlled by heat source in the 3D printer. Nozzle is connected with heat block and barrel, and heat block contains heat source. Nozzle becomes hot through heat conduction from heat source. Nozzle temperature has been predicted for various thermal boundary conditions by computer simulation and compared with experimental measurement. Nozzle temperature highly depends upon thermal conductivities of heat block and nozzle. Simulation results are good agreement with experiment.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.1
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• pp.52-59
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• 2012

Objectives: The purpose of this study was to evaluate the exposure possibility of by-products during the semiconductor manufacturing processes. Methods: The authors investigated types of chemicals generated during semiconductor manufacturing processes by the qualitative experiment on generation of by-products at the laboratory and a literature survey. Results: By-products due to decomposition of photoresist by UV-light during the photo-lithography process, ionization of arsine during the ion implant process, and inter-reactions of chemicals used at diffusion and deposition processes can be generated in wafer fabrication line. Volatile organic compounds (VOCs) such as benzene and formaldehyde can be generated during the mold process due to decomposition of epoxy molding compound and mold cleaner in semiconductor chip assembly line. Conclusions: Various types of by-products can be generated during the semiconductor manufacturing processes. Therefore, by-products carcinogen such as benzene, formaldehyde, and arsenic as well as chemical substances used during the semiconductor manufacturing processes should be controlled carefully.

• Journal of Aerospace System Engineering
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• v.11 no.4
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• pp.30-35
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• 2017

In this work, a manufacturing and structural test of 1kW class horizontal axis wind turbine blade using natural-fiber composite was performed. The aerodynamic design of blade was performed after investigation on design requirement. The structural design load was investigated after aerodynamic design of blade. And also, structural design of blade was carried out. The structural design of blade was carried out using the simplified methods such as the netting rule and the rule of mixture applied to composite. The structural safety of the designed blade structure is investigated through the various load cases, stress, deformation and buckling analyses using the FEM method. Finally, the blade manufacturing and structural test using natural composite was carried out.