• 한국소음진동공학회논문집
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• 제18권7호
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• pp.718-724
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• 2008

A flexible structure submerged in acoustic fluid is affected by its surrounding fluid. In this case, the coupling effects between structures and surrounding fluid have an effect on the submerged structure as external force and change impedance of acoustic domain. Therefore, the coupling effects by its surrounding fluid complicatedly change the characteristics of a submerged structure such as natural frequencies and damping coefficients. In this paper, using the analytic modal equation of a spherical shell surrounded by water and air, the complex changes of damping coefficients and natural frequencies of submerged structures are studied for various external acoustic fluid and structures.

• 정보저장시스템학회논문집
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• 제1권2호
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• pp.132-136
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• 2005

It is widely accepted that the reading mechanism of Super-RENS(super-resolution near field structure) and Super-ROM(super-resolution read only memory) is closely related with non-linear temperature dependent material properties such as refractive indices, phase change. Furthermore, the dynamic change of the temperature distribution also an essential part of reading mechanism of Super-RENS/ROM. Therefore, the knowledge of the temperature distribution as a function a time is one of the important keys to reveal the physics of reading mechanism in Super-RENS/ROM. We calculated time-dependent temperature distribution in a 3-dimensional Super-ROM disk structure when moving laser beam is irradiated. With a help of commercial software FEMLAB which employed finite element method, we simulated the temperature distribution of ROM structure whose pit diameter is 120-nm with 50-nm depth. Energy absorption by moving laser irradiation, time variations of heat transfer processes, heat fluxes, heat transfer ratios, and temperature distributions of the complicate 3-dimensional ROM structure have been obtained.

• 한국세라믹학회지
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• 제36권9호
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• pp.937-945
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• 1999

반응결합 탄화규소(RBSC) 반응관을 보호하기 위하여, 반응결합 탄화규소 기판 위에 탄화규소를 1~10 범위의 입력기체비(${\alpha}=P_{H2}/P_{MTS}=Q_{H2}/Q_{MTS}$)와 1050~1300$^{\circ}C$범위의 증착온도에서 methyltrichlorosilane(MTS)로부터 수소분위기에서 저압화학기상법으로 증착하였다. 1250$^{\circ}C$의 증착온도에서 입력기체비가 감소함에 따라 증착속도는 증가하다가 감소하였다 입력기체비가 높을 때에는 (111) 우선배향성을 나타내고 과립형의 미세구조를 보이며, 입력기체비가 작을 경우에는 (220) 우선배향성을 가지는 마면주상의 미세구조가 관찰되었다. 증착온도가 증가함에 따라 입력기체비와 비슷하게 미세구조의 변화하는결과를 얻었으며, 이러한 결과는 증착기구의 변화와 밀접한 관련이 있다. 일정한 증착온도에서 입력기체비의 조정를 통하여 얻었으며, 이러한 결과는 증착기구의 변화와 밀접한 관련이 있다. 일정한 증착온도에서 입력기체비의 조절을 통하여 과립형과 미면주상의 미세구조를 함께 가지는 복층구조를 연속공정을 통하여 성공적으로 제조하였다.

• 한국전기전자재료학회논문지
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• 제36권6호
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• pp.609-613
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• 2023

In this paper, a 1,200 V Si-based IGBT used in electric vehicles and new energy industries was designed. A field stop IGBT with a separate gate structure, which is the proposed structure, was designed to change trench depth and split gate width variables. Then, the general trench structure and electrical characteristics were compared and analyzed. As a result of conducting the trench depth experiment, it was confirmed that the breakdown voltage was the highest at 6 ㎛, and the on-state voltage drop was the lowest at 3.5 ㎛. In the separate gate width experiment, it was confirmed that the breakdown voltage decreased as the variable increased, and the on-state voltage drop increased. Therefore, it may be seen that it is preferable not to change the width of the separate gate. In addition, experiments show that there is no difference in on-state voltage drop compared to a structure in which a general field stop structure has a separate gate structure. In other words, it is determined that adding a dummy gate with a separate gate structure to the active cell will significantly improve the on-voltage drop characteristics, while confirming that the on-voltage drop does not change, and while having excellent characteristics in terms of breakdown voltage.

• Applied Microscopy
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• 제38권2호
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• pp.73-79
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• 2008

현재 생물학 분야에서 세포 구조를 3차로 구현하기 위해 전자 현미경을 이용하는 연구는 매우 빠르게 발전하고 있다. 최근에는 시료의 구조를 변형시키는 화학 고정법 대신 시료를 빠른 시간 내에 동결고정시킴으로써 구조 변형 없이 세포 3차 구조 구현이 가능해졌다. 이러한 기술의 도입으로 단편이미지로만 세포 구조를 이해해왔던 지금까지와 달리 Cryo-ET를 통해 인위적인 구조 변형 없는 3차 구조 구현이 가능해졌고, 이 기법은 약물전달, 나노 공학 등 여러 학문 분야에 활용됨으로써 학문 발전에 이바지 할 것이다.

• The Journal of Asian Finance, Economics and Business
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• 제8권1호
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• pp.45-52
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• 2021

The capital structure is one of the hot financial topics among researchers and scholars. Its importance comes from the fact that capital structure is closely related to companies' ability to meet different stakeholders' needs. A suitable capital structure will boost the business and create a competitive advantage in the context of fierce competition. Many companies choose an optimal debt level based on the trade-off between interest and debt costs. This study aimed to test the existence of trade-off theory in capital structure, the case of Vietnam's real estate companies, which are growing very fast recently. Instead of considering constant optimal leverage to test the trade-off model, we take advantage of the dynamic capital structure determined by growth opportunities, profitability, tax incentives, tangibility, liquidity, and firm size. The dynamic panel data regression was estimated by the system Generalized Method of Moment (Sys-GMM). The empirical evidence showed that real estate companies listed in the Vietnamese stock market might change their leverage toward a target capital structure determined by influential factors in a long-term perspective. In particular, the debt-to-asset ratio will change by approximately 14 percent, positively, in response to the difference between the current debt-to-asset ratio and the dynamic target debt-to-asset ratio.

• 지능정보연구
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• 제10권2호
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• pp.111-131
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• 2004

소프트웨어 유지보수 단계에서는 고객니즈, 마케팅 정책, 법, 제도의 변화 등으로 인한 다양한 시스템 변경 요구를 수용하여야 한다. 그러나, 소프트웨어의 비가시성문제로 인해 새로운 변경 요구사항 발생 시 수정 대상 모듈을 발견하는데 지대한 시간이 요구될 뿐 아니라 모듈의 재 사용을 어렵게 만들어 중복 모듈이 양산 됨으로써 향후 장애의 근원이 되는 악순환이 전개된다. 이에 본 연구에서는 시맨틱 웹(Semantic Web) 기술을 활용하여 이동통신사의 과금/청구 도메인의 관리자와 개발자들이 공유하고 있는 개념과 개념간 관계를 명시적으로 표현하고 이를 이용하여 변경대상 모듈을 쉽게 발견 할 뿐 아니라, 발견된 모듈에 대해 구조적 호출 및 조립 관계를 분석하도록 지원하는 온톨로지 기반 변경 영향 분석 시스템(OntCIA; Ontology based Change Impact Analysis System)을 제시한다. OntCIA는 스트링 매칭과는 근본적으로 다른 의미적 모듈검색을 지원하며 잦은 변경이 요구되는 호출 및 조립 구조 정보는 데이터 베이스에서 관리하고 도메인 지식은 온톨로지로 관리함으로써 유지 보수가 용이한 구조를 가진다.

• 분석과 대안
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• 제6권1호
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• pp.195-222
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• 2022

From the economic development perspective, economic growth should accompany structural improvement in order to meet complex demands from a society. In the context of development economics, economic growth is critically dependent on successful structural advancement. The issue of structural change is also important for advanced economies as the landscape of modern industry is changing fast. Many advanced countries of slow growth are experiencing dawdling changes in industry structure. However, there is no definitive answer to the question of whether there is a causal relationship between structural change and growth. This study empirically assesses the relationship between structural change or 'speed' thereof and economic growth in developed countries of OECD. Rather than looking into the causes of structural changes, this study simply measures structural changes in OECD economies and examines if structural change is really contributing to growth. The reason why this study focuses on advanced countries of OECD is rather obvious; technological innovation and emergence of new industries pressure these countries to restructure their economies to address these new challenges though they are at stages well beyond conventional industrialization. And structural rigidity can always limit growth even in advanced countries. The main results of this study can be summarized as a positive relationship between 'change and growth'. 'Change' in this study refers to changes in the industrial structure based on value-added and was analyzed to have a close positive relationship with economic growth. This result is consistent with arguments of early development economists emphasizing structural upgrade as an indispensable process for growth and development. The result of this study potentially confirms that the main argument of development economics is valid also for advanced economies. One of our results suggests that business/professional services and social services should be main targets for restructuring for advanced economies. The rational may be that rapid convergence of manufacturing and services is a key for structural advancement in the era of new technologies. Obviously, as manufacturing technology and production are standardized, it is difficult to secure international competitiveness through traditional manufacturing alone and the role of R&D, design, logistics, and marketing is becoming more important.

• 한국의류학회지
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• 제30권11호
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• pp.1495-1506
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• 2006

The purposes of this study are to investigate the formation and the change of apparel retail structure historically with the viewpoint that the retail structure is affected by the process of economic development. This study was done by literature research method and the result of this study is the following. The tailor and seamstress shops, the first clothing shops in Korea, were replaced by ready-made shops, because mass production system which had developed with the industrialization of Korea increased the advantage of economy of scale compared to handicrafts individual one. After that, the production system of apparel industry had been efficient continuously, while retail system had not. The retailing of famous brand apparel conducted by exclusive franchise store caused supplier oriented markets where the opinion and the desire of consumers were not reflected. While the retailing of the unknown brand apparel handled by small retail stores were inefficient. As the apparel industry matured in 1990s, various types of new stores appeared such as specialty stores, discount stores, TV home shopping, internet shopping, outlet malls, and big fashion stores in Dongdeamoon. These new stores have features of seeking profits in mass merchandising. As these large retail stores grow, the apparel retail structure of Korea is changing from a fragmented market to a vertically integrated one. This change is shown by the decrease of stores per inhabitants. With the change of environment, the apparel retail system which has lagged behind comparatively is expected to develop into more efficient system based on the large capital investment which raise the advantage of economy of scale.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.177-180
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• 2003

We investigated transmittance, surface characteristics, and resistivity according to bending of ITO(indium tin oxide) film with four other multi-barrier film. Transmission data of ITO film with four ITO films showed there was about large 90% transmission above 550nm wavelength at three multi-barrier structures. But, both-side hard coated structure showed relatively low 75% transmission above 550nm wavelength. And, surface images measured from SEM(scanning electron microscope) showed both-side hard coated structure have a tendency of more roughness. Also, resistivity change of four other multi-barrier film showed there was the lowest change at one-side hardcoated structure. Subsequently, with result of resistivity change according to position, we knew the resistivity change of the center increased rapidly than that of the edge.