• Journal of the Microelectronics and Packaging Society
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• v.25 no.4
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• pp.9-15
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• 2018

This paper shows the principles and characteristics of the transient liquid phase (TLP) bonding technology for power modules packaging. The power module is semiconductor parts that change and manage power entering electronic devices, and demand is increasing due to the advent of the fourth industrial revolution. Higher operation temperatures and increasing current density are important for the performance of power modules. Conventional power modules using Si chip have reached the limit of theoretical performance development. In addition, their efficiency is reduced at high temperature because of the low properties of Si. Therefore, Si is changed to silicon carbide (SiC) and gallium nitride (GaN). Various methods of bonding have been studied, like Ag sintering and Sn-Au solder, to keep up with the development of chips, one of which is TLP bonding. TLP bonding has the advantages in price and junction temperature over other technologies. In this paper, TLP bonding using various materials and methods is introduced. In addition, new TLP technologies that are combined with other technologies such as metal powder mixing and ultrasonic technology are also reviewed.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.2
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• pp.81-86
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• 2019

Although the localization rate of shipbuilding and marine equipment goods is set to be 70 percent by 2020, but the localization rate of equipment and materials for shipbuilding and marine facilities is currently 10 to 30 percent. For Korea's Big 3 shipbuilders, which build 70 percent of the world's largest shipbuilders, localization of shipbuilding equipment and equipment is an essential factor. In particular, there is a growing need to localize equipment and materials in terms of the number of lead standards and A/S. It is expected that there will be a rapid expansion of LNG carriers in the future, and it is necessary to develop equipment and equipment materials of LNG ships. In this study, the design and manufacture of LNG vessel equipment was conducted. Design and basic performance tests of 4-inch QCDC for LNG bunkering were conducted.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.4
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• pp.17-23
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• 2018

Recently, electric semiconductors became an issue because of efficient use of energy and compaction of electronics. Silicon electric semiconductors are difficult to put into it because of its physical limitations. Hence, the study of WBG (Wideband Gap) semiconductors like SiC and GaN began. These devices received attention because it can be miniaturized and worked at high temperatures over $300^{\circ}C$. WBG MOSFET electric semiconductors can show performance like silicon IGBT. This can solve the current problem of IGBT tail. The current study shows the technical principles and issues related to SiC and GaN power semiconductors. WBG devices can achieve high performance compared to silicon, but its performance can't be fully utilized because of lack in bonding technology. Therefore, this review introduces research on WBG devices and their packaging issues.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.4_2
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• pp.481-490
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• 2021

In the ultrasonic welding machine, when the load fluctuates, the L and C of the piezo element in the oscillation part change. As a result, the resonant frequency is changed, so it is necessary to match the operating frequency of the ultrasonic welding machine to the new resonant frequency. That is, in order to maximize the output of the oscillation unit of the ultrasonic welding machine, it is inevitable to follow the resonance frequency. Accordingly, many methods for following the resonant frequency are being actively studied. In addition, in order to check the effect of external inductance on the operation of the ultrasonic welding machine, The equivalent circuit of the piezo element was analyzed by including the external inductance for resonance in the equivalent circuit of the piezo element, and the method of selecting an appropriate inductance was described. In this paper, we propose a new system that allows the switching frequency of the inverter to tracking the resonance frequency even if the resonance frequency is changed due to the load of the ultrasonic welding machine.

• Journal of the Korea Safety Management & Science
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• v.23 no.1
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• pp.81-94
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• 2021

In SMEs, technological innovation is recognized as an important tool in terms of sustainable growth. This study analyzed the determinants of technological innovation by using the information of the corporate panel DB composed of local SMEs. The internal factors were added with technological innovation capacity and production capacity and the industrial cluster environment was first applied to external factors. Also, whether the industrial cluster environment influences technological innovation through R&D capabilities, the mediating effect was tested with the Sobel Test. Among the internal and external factors, the most important determinant was marketing ability, and a policy was proposed to develop measures to increase R&D capability with mediating effect. Among the technological innovation variables, which are dependent variables, the most determinant factor was the proportion of new product sales. For this, it is considered that additional research such as longitudinal research with the concept of repetition and parallax using the corporate panel DB is necessary.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.4_2
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• pp.491-499
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• 2021

Batteries are widely used for energy storage, such as ESS(Energy Storage System), electric vehicles, electric aircraft, and electric powered ships. Among them, a submarine uses a high power battery for an energy storage. When the battery of a submarine is discharged, a diesel generator generates AC power, and then AC/DC power converter change AC power to DC power for charging the battery. Therefore, in order to lower the current capacity of the diesel generator, it is necessary to use an AC/DC converter with a high input power factor. And, a power converter with a large power capacity must have high stability because it can lead to a major accident when a failure occurs. However, the control algorithm using the traditional PI controller is difficult to satisfy stability and dynamic characteristics. In this paper, we design the high power AC/DC converter with high input power factor for battery charging systems. And, we propose a stable control algorithm. The validity of the proposed method is verified through simulation and experiments.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.3
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• pp.36-42
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• 2022

Whereas the necessity for recycling and reuse is being emphasized owing to the depletion of resources and waste disposal problems caused by the continuous development of the industry, the importance of remanufacturing has been highlighted recently. Re-manufacturing involves a series of processes in which failed disposal or aging goods are recovered to a state similar to that of a new product. In this regard, machine tools, which are large structures, can achieve the effect of remanufacturing. Among the various elements constituting the machine tool, the main spindle portion that affects the processing precision is critical. Therefore, this study is conducted to derive improvement measures for the main axis of an old Miller planner via reverse engineering and central composite design, which is one of the core processes of remanufacturing.

• The Research Journal of the Costume Culture
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• v.30 no.5
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• pp.689-702
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• 2022

Global fashion houses have recently incorporated traditional Korean motifs within their inspiration. This trend is an opportunity to showcase the colors of traditional Korean culture by investing in the new design content. Products specifically based on traditional Korean culture are lacking in brand awareness despite the success of Korean content. Accordingly, this study designs cultural products based on Korean folk painting that captures Korean people's satirical sense of humor. Korean folk painting theories are analyzed, from which different types of folk paintings are classified based on research of bibliographies and online documents. Following classification, the results are dataized as different types of folk paintings and their meanings. Furthermore, images of folk paintings are categorized and scanned digitally. The digitized images of the folk paintings are processed through Adobe Photoshop CS for overall layout and Adobe Illustrator CS for detailed designs. Traditional categories of Korean folk paintings are used, including flowers and birds, letters, and study stationery. Using the main elements of the flower and birds category, designs with cultural products such as images of flowers, birds, animals, and fish are produced. The final designs are used to create fashion items that can easily be used for embellishment or self-presentation: a scarf and a necktie. The scarf and the necktie are not only merchandise; they also symbolize the story, humor, and hope that Korean folk paintings once symbolized.

• 한국벤처창업학회:학술대회논문집
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• 2020.11a
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• pp.61-67
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• 2020

현재 글로벌 환경은 빠르게 변화하는 4차 산업혁명의 도래로 산업구조는 물론 사회경제 전반에 걸쳐 거대한 변화에 직면하고 있으며, 미래에 대한 불확실성이 깊어져서 이에 대한 빠른 대응이 필요한 시대가 되었다. 또한 4차 산업의 주축인 디지털 혁명과 코로나 19 팬데믹 사태로 변화의 가속화가 진행되면서 이러한 변화에 얼마나 신속하게 대응하느냐가 생존과 성장의 핵심이 되었다. 본 연구는 기존의 선행 문헌연구를 바탕으로 기술기반 창업기업의 창업가 역량과 기업성과 간의 인과관계를 통합적으로 규명하는 것을 목적으로, 불확실한 경제 상황 속에서 기술창업과 창업가 역량의 중요성을 인식하여 기업성과에 영향을 주는 요소를 분석하고자 한다. 이와 같은 목적을 달성하기 위하여 창업가 역량을 독립변수로 하고, 정부지원활용을 매개로, 창업가 일반적 특성(업종, 업력, 창업경험, 특허보유, CTO인력보유 여부 등)을 조절변수로 하여 기업성과에 미치는 영향에 대한 연구모형을 설정하였다. 연구모형 검증을 위해 대전 대구 지역의 연구개발특구, 산업기술단지, 첨단산업단지, 창업보육센터, 테크노파크등, 기술집접화시설에 입주해 있는 217개 기업을 대상으로 온 오프라인 방식의 설문조사를 실시하였다.

• Korea Trade Review
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• v.46 no.4
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• pp.167-188
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• 2021

This study was carried out to identify the key drivers behind the rapid growth of the cosmetic medical tourism industry in recent years and determine the future growth engines. Unlike previous studies that have focused on cosmetic medical tourism in the United States, Japan, and China, this paper examines the related trends in ASEAN countries, where the interest in cosmetic surgery has recently surged among young people, as part of the efforts to promote the expansion of the industry in this particular region. The results of the empirical study showed that those from the ASEAN region traveling abroad for cosmetic surgery found the medical professional's expertise in cosmetic surgery technology, medical care system, and administrative convenience in relation to communication and accessibility appealing, and this is what led to an intention to visit. As for another process that formed the intention to visit, it was the sociocultural attitudes towards appearance arising from the attractiveness of celebrities, and this had an impact on the intention to visit abroad for cosmetic surgery. Especially it was newly discovered, based on an empirical analysis, that sociocultural attitudes towards the appearance and attractiveness of celebrities could be a key influencing factor when it comes to the intention to visit another country for cosmetic surgery.