• IE interfaces
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• v.21 no.2
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• pp.151-160
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• 2008

Defect size distribution is a probability density function for the defects that occur on wafers or glasses during semiconductor/LCD fabrication. It is one of the most important information to estimate manufacturing yield using well-known statistical estimation methods. The defects are detected by automatic optical inspection (AOI) facilities. However, the data that is provided from AOI is not accurate due to resolution of AOI and its defect detection mechanism. It causes distortion of defect size distribution and results in wrong estimation of the manufacturing yield. In this paper, I suggest a size conversion method and a maximum likelihood estimator to overcome the vague defect size information of AOI. The methods are verified by the Monte Carlo simulation that is constructed as similar as real situation.

• IE interfaces
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• v.21 no.3
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• pp.302-311
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• 2008

Efficiency evaluation methods of manufacturing processes have relied on absolute measures such as defective rate and throughput per person, ignoring various process characteristics. To overcome the limitation, we propose an evaluation model which reflects characteristics of each process. It is composed of three measures : utilization, performance, and improvement. The suggested model utilizes a combination of DEA and AHP methods. The proposed method has been applied to efficiency evaluation of cellular phone case manufacturing processes.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.14-20
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• 2015

Molding technologies for plastic microstructures have been extensively investigated during the last two decades, and theoretical and numerical studies on the micro molding process have provided efficient tools for the development of such molding technologies. In this paper, we present a review of numerical simulation methods for the micro molding process. Basic models for a description of the material property, governing equations of the flow and heat transfer during the molding process, and numerical methods will be described. Particularly, numerical simulations for micro injection molding and hot embossing processes will be presented, and their main features noted and compared to those for conventional molding processes.

• Journal of the Korean Society of Safety
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• v.20 no.1 s.69
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• pp.148-152
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• 2005

The purpose of this paper is to investigate risk factors and ergonomically improve the manufacturing lines of compressors for prevention of work-related musculoskeletal disorders, enhancement of productivity, and workers satisfaction We executed questionnaire survey, ergonomic risk factors investigation of manufacturing lines and ergonomic intervention of work methods, workplace and hand tools. The results of the questionnaire showed that $7.9\%$ of respondents were positive in WMSDs symptom survey. In ergonomic evaluation, the analysis methods such as RULA and NIOSH lifting equation were used and 28 processes in the lines were evaluated to be potentially hazardous. We ergonomically improved the processes to reduce potential WMSDs hazards : manual material handling, carts, work tables, transport methods, working posture and hand tools.

• The Korean Journal of Food And Nutrition
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• v.20 no.3
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• pp.276-281
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• 2007

Oddi is a mulberry fruit that has anti-inflammatory and antioxidative effects. This study was carried out to investigate the quality characteristics of mulberry fruit wines manufactured by two different methods. Where they were processed according to the traditional Korean fruit wine methodology(A) or a modified(B). Sensory qualities, physiochemical characteristics, and biochemical activities of the Oddi wines were analyzed. From the results of the sensory evaluation, manufacturing method A showed higher acceptability. However, the two different methods was not significantly different overall. The method A wine had higher brightness(L)(77.65) redness(a), and yellowness(b). As for the antioxidant activities and ACE(angiotensin-converting enzyme) inhibitory abilities of the wines manufacturing method A had greater values.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.193-194
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• 2007

In this paper we present work done by Kodak Graphic-Communications-Group and our partners demonstrating applications where laser direct imaging could replace photolithography in display manufacturing. Such applications range from direct manufacturing (e.g. LCD color-filters) to producing “masters” where manufacturing is done by traditional printing methods (e.g. flexography, Gravure-printing).

• Journal of the Ergonomics Society of Korea
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• v.30 no.4
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• pp.465-472
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• 2011

Objective: The aim of this paper is to introduce ergonomic evaluation methods for agricultural work. Background: Work-related Musculoskeletal Disorders(WMSDs) became a major problem in agriculture industry recently. A number of ergonomics evaluation methods have been developed in order to evaluate the work load for preventing WMSDs. The workload evaluation methods were developed for manufacturing industry. Therefore, these ergonomic evaluation methods were used carefully in agriculture industry because work type in agriculture different from work type in manufacturing. Method: Various references of ergonomic evaluation methods such as OWAS, REBA, RULA, NLE and Snook table have been reviewed for agricultural work. Results: This paper presents the characteristics, the selection and application procedure of ergonomic evaluation methods for agricultural work. Application: These results can be used to provide baseline information for ergonomic evaluation methods.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.2
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• pp.149-156
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• 2011

There is much information of equipment in shop floor because the manufacturing processes are different as the equipment within the manufacturing process is varied. To provide effective process information to MES and other production systems, the DAS requires an equipment monitoring system that takes into account the characteristics of the equipment on the shop floor. In this study, we proposed some methods for collecting the required information about various equipments on a shop floor. The equipments such as CNC can be interfaced with the DAS by using a PLC-based method and a sensor-based interface board can be used to interface general equipments. The proposed methods can be used to collect information on the shop floor in real-time. Moreover these methods are very adaptive and can be easily modified according to the changes made to the shop floor. The information about a real shop floor acquired by employing these methods is saved in a database and the can be provided to a supervisor and MES so that they are aware of the status of the shop floor.

• Journal of Powder Materials
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• v.27 no.6
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• pp.509-519
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• 2020

A well-established characterization method is required in powder bed fusion (PBF) metal additive manufacturing, where metal powder is used. The characterization methods from the traditional powder metallurgy process are still being used. However, it is necessary to develop advanced methods of property evaluation with the advances in additive manufacturing technology. In this article, the characterization methods of powders for metal PBF are reviewed, and the recent research trends are introduced. Standardization status and specifications for metal powder for the PBF process which published by the ISO, ASTM, and MPIF are also covered. The establishment of powder characterization methods are expected to contribute to the metal powder industry and the advancement of additive manufacturing technology through the creation of related databases.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.150-155
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• 2016

To evaluate the autofocusing performance of recent mobile phone cameras, it is necessary to determine the peak position of the center field MTF (Modulation Transfer Function), -known as the through focus MTF- of the module. However, the MTF peak position found by conventional methods deviates from the ideal position due to the focus scanning resolution of mobile phone cameras. This inaccurate peak position results in false judgements of the optical performance, leading to yield losses or customer complaints. An increase in the focus scanning resolution can address this problem, but the manufacturing UPH (Unit per Hour) level will also unfortunately increase as well, resulting in a loss of manufacturing capabilities. In this paper, several fitting models are studied to find an accurate MTF peak position within a short period of time. With an analysis of a large amount of manufacturing data, it is demonstrated that the fitting methods can reduce false judgements and simultaneously increase the capabilities of the manufacturing system.