• Journal of Korea Foundry Society
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• v.41 no.2
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• pp.127-131
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• 2021

Based on its good compatibility with high-temperature environments, the Ti-48Al-2Cr-2Nb alloy is used for high-temperature materials of industrial equipment. In this study, a Ti-48Al-2Cr-2Nb alloy turbocharger turbine wheel was fabricated by a vacuum centrifugal casting method. The conditions that prevent misrun defects of the turbocharger turbine wheel blade from centrifugal casting using alumina molds were investigated. The microstructure of the alloy prepared by vacuum centrifugal casting was studied by means of optical microscopy (OM), with a micro-Vickers hardness analyzer (HV), by X-ray diffraction (XRD) and by SEM-EDS. The HV and SEM-EDS examinations of the as-cast Ti-48Al-2Cr-2Nb alloy showed that the thickness of the oxide layer (α-case) was typically less than 50 ㎛. At a high preheating temperature of 1,100℃, a moderate RPM of 260, and with an alumina mold with a large gate size, there were almost no misrun defects. Therefore, it was confirmed that a Ti-48Al-2Cr-2Nb alloy turbocharger turbine wheel with fewer misrun defects could be achieved through a high preheating temperature, a moderate RPM, a large gate size and an alumina mold to suppress the formation of alpha-case components.

• Journal of the Ergonomics Society of Korea
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• v.26 no.1
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• pp.71-77
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• 2007

Shoe's size and shape are determined by the last that takes shape of foot because last is the mold of shoe in development and manufacturing process. Then adaptation between foot and shoe is dependent on the last. In mass shoe production, model size is developed in the first place, other sized lasts are made through the grading process based on model size. The most important factor in grading system is grading deviation that must be same amount induced from foot measuring database. At present, most of the last manufacturing companies in korea using 260mm as a standard foot model size. When length grading deviation is 5mm, the ball girth grading deviation is 3.7mm and the ball width grading deviation is 1.2mm. I verified existing grading system by comparing grading results with foot measuring data. Also, I proposed reasonable grading deviation and application method of grading system. From the analysis of foot measuring database, reasonable grading deviations are 1.22mm in ball width and 0.84mm in ankle height in case of length grading deviation is 5mm. I confirmed that the current grading system is very accurate. When we grade last from 230mm to 290mm by current grading system based on model size 260mm, there is grading error over 1mm in the front outside area of foot. This error level of 1mm is no problem in normal walking shoe's last, but it induces adaptation problems in sports and special purposed shoe's last. Therefore using of three standard model size is recommended in grading men's last for reducing grading deviation error under the level of 1mm. It is specifically described as 235mm in 225-245mm, 260mm in 250-270mm, 285mm in 275-295mm. According to the above recommended grading system, it is enough to measure only three foot sizes in case of foot measuring project for men's last development.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.1
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• pp.41-45
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• 2018

As the size of semiconductor chip shrinks, the electronic industry has been paying close attention to fan-out wafer level packaging (FO-WLP) as an emerging solution to accommodate high input and output density. FO-WLP also has several advantages, such as thin thickness and good thermal resistance, compared to conventional packaging technologies. However, one major challenge in current FO-WLP manufacturing process is to control wafer warpage, caused by the difference of coefficient of thermal expansion and Young's modulus among the materials. Wafer warpage induces misalignment of chips and interconnects, which eventually reduces product quality and reliability in high volume manufacturing. In order to control wafer warpage, it is necessary to understand the effect of material properties and design parameters, such as chip size, chip to mold ratio, and carrier thickness, during packaging processes. This paper focuses on the effects of thickness of chip and molding compound on 12" wafer warpage after PMC of EMC using finite element analysis. As a result, the largest warpage was observed at specific thickness ratio of chip and EMC.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.130-134
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• 2016

Due to the need for advanced technologies in the automotive industry, the demand for lighter and safer vehicles has increased. Even though various nonferrous metals, like Aluminum, Magnesium and also Carbon Fiber Reinforced Plastic (CFRP), have been implemented in the automotive industry, a lot of technical research and development is still focused on ferrous metals. In particular, the market volume of High Strength Steel (HSS) parts and Ultra High Strength Steel (UHSS) by hot press forming parts has expanded significantly in all countries' automotive industries. A new tool steel, High Thermal-Conductivity Tool Steel (HTCS), for stamping punches and dies has been developed and introduced by Rovalma Company (Spain), and it is able to support better productivity and quality during hot press forming. The HTCS punches and dies could help to reduce cycle time due to their high thermal conductivity, one of the major factors in hot press forming operation. In this study, test dies were manufactured in order to verify the high thermal conductivity of HTCS material compared to SKD6. In addition, thermal deformation was inspected after the heating and cooling process of hot press forming. After heating and cooling, the test dies were measured by a 3D scanner and compared with the original geometry. The results showed that the thermal deformation and distortion were very small even though the cooling time was reduced by 2 seconds.

• Journal of Fashion Business
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• v.7 no.2
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• pp.55-68
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• 2003

The purpose of this research is to expand the realm of a button for a decorative purpose through embossing the effect and gravity of a button in fashion by designing the new ceramic buttons which are mainly used for decorative function in costume. In order to acquire a motif for the design, I analyzed several works of Gustav Klimt. As the result, those feature can be classified into the use of decorative lines, mosaic forms, and harmony of golden yellow and black, and it can be applied to buttons and clothes design. The sort of clay used in manufacturing the ceramic buttons was white clay to have high density and to diffuse light well, and press shaping techniques using plaster mold were employed. The baking was performed in an electronic kiln at $800^{\circ}C$ for the first time and at $1250^{\circ}C$ for the second time. Based on wearable designs in 2002/2003 F/W Trend of Interfashion Planning, I made three pieces of dress which could express the button's capability of decoration with effect. This is expressing a simplified form which shows up in details of and yellow and red pink were used to harmonize with golden yellow clothes. As an application of shapes of foliage in I transformed its size and form to be consistent with a jacket and a tube top. To accord with golden beige costume, I made a curve, showing up in Klimt's paintings, with golden color on a circle shape which was also a main motif in his paintings.

• Archives of design research
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• v.16 no.2
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• pp.197-208
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• 2003

A recent trend for product development requires that product design firms participate in every process in cooperations with clients. So, this study proposed an advanced practical management process for product design according to the new trend Because existing processes explain summary steps just including market research, design, engineering, manufacturing., to support the recent trend, an extended process which explains every steps should be prepared. Design development precesses include initial meeting, contact, kick-off meeting, market research, idea sketch, rendering, design drawing, design mock-up, design manual, engineering drawing, ES mock up, mold, manufacturing, and patent. To manage these whole design processes, designers should have abundant knowledge about them. This process has three merits: 1) understanding the whole processes, 2)the unity between design and manufactures, 3)collecting accurate information by market research, 4)elevating design quality. So, designers are able to manage whole product development processes. This practical management process proposes an advanced structure for product design development, and can be accepted for various product design development environments.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1991.10a
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• pp.261-267
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• 1991

다품종소량생산의 특징을 갖고 있는 금형공업에서 컴퓨터통합생산시스템(Computer Integrated Manufacturing System;CIMS)의 실현을 위한 중요한 분야의 하나는 부품설계도면으로부터 최종제품을 생산하는데 필요한 공정계획의 자동화, 즉 컴퓨터를 이용하여 공정계획을 자동적으로 생성하는 자동공정계획시스템(Computer Aided Process Planning;CAPP) 기술의 개발이다. 국내외적으로 CAPP분야의 연구는 컴퓨터 지원에 의한 자동화 기술의 급속한 발전과 더불어 지난 20여년 동안에 기계가공품에 관한 CAPP은 약 150여가지가 개발되었으나, 이는 컴퓨터 지원에 의한 설계의 자동화(Computer Aided Design;CAD)나 컴퓨터 지원에 의한 제조의 자동화(Computer Aided Manufacturing;CAM)분야에 비해 상대적으로 저조한 형편이다. 특히 금형을 대상으로 한 CAPP시스템의 개발은 아직 초기단계에 있기 때문에, 본 연구에서는 사출금형을 대상으로 하여 실용성이 있는 공정설계시스템을 개발함을 목적으로 한다. 일반적으로 공정계획은 "소재로부터 제품을 경제적, 효율적으로 생산하는데 필요한 제조공정의 체계적인 결정"이라고 정의할 수 있다. 공정계획은 제품의 종류와 수량, 재료와 부품의 종류, 보유 생산설비와 제조기술의 수준에 따라 다르나, 공정설계(Process Design)와 작업설계(Operation Design)로 구분할 수 있다. 본 연구에서는 공정계획을 광의의 공정설계로 정의하고, 공정설계와 공정계획을 동의어로 통용토록 한다. 기존의 CAPP시스템의 개발에 관한 기본적인 접근방법은 변성형방법(Variant method), 창성형방법(Generative method) 및 자동화방법(Automatic method)이 있다. 이들 CAPP시스템을 개발할 때 사용하는 기법은 크게 5가지- (1) GT(group Technology) 접근기법, (2) Bottom-up 접근기법, (3) Top-down 접근기법, (4) AI와 전문가시스템(Expert System) 접근기법, (5) 컴퓨터 프로그래밍 언어 - 로 분류할 수 있다. 본 연구에서는 전문가시스템 기법을 도입해서 사출금형 공정계획전문가의 지식과 경험을 획득하여 지식베이스를 구축하고, 전문가시스템 셀(shell)중 CLIPS를 이용하여 자동공정계획시스템인 Mold CAPP을 개발하였다.PP을 개발하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.10
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• pp.1514-1519
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• 2001

This paper is concerned with design, manufacturing and performance test of LIPCA ( Lightweight Piezo- composite Curved Actuator) using a top carbon fiber composite layer with near -zero CTE(coefficient of thermal expansion), a middle PZT ceramic wafer and a bottom glass/epoxy layer with high CTE. The main point of this design is to replace the heavy metal layers of THUNDER by thigh tweight fiber reinforced plastic layers without losing capabilities to generate high force and large displacement. It is possible to save weight up to about 30% if we replace the metallic backing material by the light fiber composite layer. We can also have design flexibility by selecting the fiber direction and the size of prepreg layers. In addition to the lightweight advantage and design flexibility, the proposed device can be manufactured without adhesive layers when we use epoxy resin prepreg system. Glass/epoxy prepregs, a ceramic wafer with electrode surfaces, and a graphite/epoxy prepreg were simply stacked and cured at an elevated temperature (177 $^{circ}C$ after following an autoclave bagging process. It was found that the manufactured composite laminate device had a sufficient curvature after detached from a flat mold. The analysis method of the cure curvature of LIPCA using the classical lamination theory is presented. The predicted curvatures are fairly in agreement with the experimental ones. In order to investigate the merits of LIPCA, a performance test of both LIPCA and THUNDE$^{TM}$ were conducted under the same boundary conditions. From the experimental actuation tests, it was observed that the developed actuator could generate larger actuation displacement than THUNDERT$^{TM}$.

• Journal of Fashion Business
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• v.21 no.5
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• pp.136-150
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• 2017

3D printing has grown tremendously as the most noteworthy new technology in the manufacturing industries. In addition, the rapid development of computer science technology with 3D printing has created a new paradigm called Fractal Geometry, or a new form of digital art. This study explores the formative characteristics of 3D printing jewelry based on presentation of fractal geometry by classification of 3D printing jewelry's morphological types that except for producible shape with traditional mold manufacturing methods. The results of the study are as follows. The morphological characteristics of 3D printed jewelry are divided into their constitutive shapes by the repetition of the unit. The organic shape determined by superposition or overlapping, the systematic shape by distortion caused by distortion, and the variation in scaling by scaling. The formative characteristics, which are drawn from a study on the shape expression of 3D printed jewelry design using fractal geometry, consist of continuity, geometrical characteristics, and exaggeration. Continuity creates a new and self-assigned new space through a recursive structure through a cyclic structure that is formed along a single directional basis. The geometry of the geometry forms a three-dimensional and constructive structure comprised of the same size and structure of the same sized unit under the mathematical order of the geometry of Fractal's geometry. Exaggeration demonstrates the informal beauty and the maximization of the shape by expanding the scaling or superposition of a unit, by scaling the scale or he distortion of the units.

• The Korean Journal of Food And Nutrition
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• v.33 no.3
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• pp.279-286
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• 2020

In this study, the properties of the substances fermented soybean producted by manufacturing with several Aspergillus strains were investigated. The five soybean cultivar that includes miso, jinpung, pyeongwon, cheonga and chamol were used in this experiment. The pH and total acidity were 6.30~6.66%, and 0.27~0.48%, respectively with differences depending on the samples. The color values for L value, a, and b value were 60.28~69.80, 0.64~3.68, and 11.48~31.21, respectively. The amylase activities, protease activities, and amino-type nitrogen of the jinpung samples were the highest among all cultivars. The mold counts the fermented soybean products by cultivars were 6.18~9.14 log CFU/g, and miso was the highest. Free amino acid and organic acid contents were highest in the jinpung and showed different composition depending on each sample. A total of 18 volatile aroma-compounds, including two acids, four alcohols, four ketones, three phenols, one furan, three pyrazines, and one miscellaneous compounds. In conclusion, it is expected that manufacturing A. oligze inoculation fermented soybean products using jinpung cultivar will improve quality.