• Title/Summary/Keyword: Theory U

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A study on Development of Design Method for Reinforced Railway Roadbed by Geocell (지오셀로 보강된 철도노반의 설계기법 개발에 관한 연구)

  • 심재범;신민호;조삼덕;채영수
    • Proceedings of the KSR Conference
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    • 2002.10a
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    • pp.614-619
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    • 2002
  • Since 1980's in U.S.A and Japan, the studies on increasing the bearing capacity of railway roadbed using geocell have been conducted for repair and reinforcement of railways constructed on soft soils. In this study, the railway roadbed system reinforced with geocells has been analyzed and investigated results of the previous studies were conducted in Korea and other nations, And the method for estimating the railway roadbed thickness was developed based on the equivalent method using the multi-layer theory and the deformation modulus Ev.

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A study on the Valuation of Resistance increase due to any quality at hull roughness (선체조도에서의 저항증가의 평가에 관한 연구)

  • 박명규;김동진;이승호
    • Journal of the Korean Institute of Navigation
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    • v.12 no.3
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    • pp.23-37
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    • 1988
  • This paper deals with the method of determining the drag of hull surface which has any quality of roughness. The method consists mainly of the theoretical point of view, then the theory enables the drag coefficient to be calculated at full scale. The hydrodynamical roughness function of hull surface ${\triangle}U_+$, affected by the hull roughness are considered as to two cases, smooth surface and rough surface case separately. The inadequacy of a single parameter to define hull roughness is discussed and thus an as additional texture parameter is proposed.

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Computational Study on the Isomers of Cyanopolyacetylenes H(C$\equiv$C)nC$\equiv$N (n=1-3)

  • Lee, Seok Jin;Park, Seong U;Lee, Seong Yul
    • Bulletin of the Korean Chemical Society
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    • v.21 no.7
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    • pp.734-740
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    • 2000
  • Density functional theory calculations are presented for the geometrical isomers of the cyanopolyacetylenes H(C≡C)n,,C≡N (n = I-3). The structures, hartmonic frequencies and dipole moments are computed, employing the 6-311G** basis set. The ener gies of barrier to isomerization (exchange of carbon and nitrogen atoms) are also computed in order to estimate the stability of the isomers in interstellar space.

Spectral Element Modeling of an Extended Timoshenko Beam: Variational Approach (변분법을 이용한 확장된 티모센코 보에 대한 스펙트럴 요소 모델링)

  • Lee, Chang-Ho;Lee, U-Sik
    • Proceedings of the KSR Conference
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    • 2008.11b
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    • pp.1403-1406
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    • 2008
  • Periodic lattice structures such as the large space lattice structures and carbon nanotubes may take the extension-transverse shear-bending coupled vibrations, which can be well represented by the extended Timoshenko beam theory. In this paper, the spectrally formulated finite element model (simply, spectral element model) has been developed for extended Timoshenko beams and applied to some typical periodic lattice structures such as the armchair carbon nanotube, the periodic plane truss, and the periodic space lattice beam.

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Buckling Analysis of Laminated Composite Plates Longitudinally Stiffened with U-Shaped Ribs (축방향 압축을 받는 폐단면리브로 보강된 복합적층판의 좌굴 해석연구)

  • Choi, Byung-Ho;Choi, Su-Young;Park, Sang-Kyun
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.3 no.1
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    • pp.29-34
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    • 2012
  • Even though the longitudinally stiffened laminated composite plates with closed section ribs should be an effective system for axially compressed members, the existing researches on the applications of closed-section ribs, especially for the laminated composite plates, are not sufficient. This study is aimed to examine the influence of the sectional stiffness of U-shaped ribs on the buckling modes and strengths of laminated composite plates. Applying the orthotropic plates with eight layers of the layup $[(0^{\circ})_4]_s$ and $[(0^{\circ}/90^{\circ})_2]_s$, 3-dimensional finite element models for the U-rib stiffened plates were setup by using ABAQUS and then a series of eigenvalue analyses were conducted. From the parametric studies, the minimum required ply thicknesses as well as the buckling strengths were presented for the analysis models. The buckling strengths were compared with the theoretical critical stress equation for simply supported plates based on the Classical laminated plate theory. This study will contribute to the future study for evaluating the minimum required stiffness and optimum design of U-rib stiffened plates.

A Study of the Āyurveda Herbal theory in the 『Suśruta-saṃhitā·Sūtrasthāna』 (Āyurveda(아유르베다)의 약물 지식에 관한 연구 - 『Suśruta-saṃhitā·Sūtrasthāna (수슈르따-상히따·수뜨라스타나)』를 중심으로 -)

  • Seo, Ji-Young;Lee, Byung-Wook;Kim, Hak-Dong;Kim, Ki-Wook
    • The Journal of Korean Medical History
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    • v.27 no.1
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    • pp.135-156
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    • 2014
  • Through a simple translation and analysis of the "Su$\acute{s}$uta-saṃhit$\bar{a}$(The fascinating tales) S$\bar{u}$trasth$\bar{a}$na(The Introduction)", I have summarized the results of the research into the $\bar{A}$yurveda Herbal theory. 1. The title of chapter 40 is "dravya-rasa-guṇa-vip$\bar{a}$ka-vij$\tilde{n}$anīya(Medcation Taste Nature Effects Digestion)", and it states theoretical knowledge on materia medica. It says that 'matter' is the most important thing, and that it decides the curing effect. Although it does acknowledge the reason behind the doctors that emphasized things like 'taste', it mainly has a critical tone. The difference in philosophies and medical theory can be seen when we compare this to the "Caraka-saṃhit$\bar{a}$", 'theory on taste'. 2. The title of chapter 41 is "dravya-vi$\acute{s}$eṣa-vij$\tilde{n}$anīya(A Discussion on the Characteristics of Materia Medica)", and the contents of the chapter have a similar tone to the thoughts of the S$\bar{a}$mkhya(數論派). All 'matter' was created by the combination of the five elements of earth, water, fire, wind, and ether, and the predominant element makes it have an earth, water, fire, wind, or ether nature. Earth has an unmoving and down going nature, and makes the body strong. Water has an irrigating nature, and moistens the tissue and induces secretion and excretion. Fire has an upward-going nature, and improves sight and complexion. Wind relaxes and dries the body, and makes the mind and body agile. Ether gives flexibility, porosity, and candidness. The title of chapter 42 is "rasa-vi$\acute{s}$eṣa-vij$\tilde{n}\bar{a}$nīya(A Discussion on the Types of Rasa(taste))". "Rasa" is an important concept in $\bar{A}$yurveda. Sometimes it is translated as 'one of the seven types of bodily tissue' and seen as chyle, and sometimes it is seen as the tastes that can be felt with the tongue such as spicy, sweet, sour, bitter, salty, and astringent(澁). Volume 1, chapter 42 of the "Caraka-saṃhit$\bar{a}$" is dedicated to the "types of taste", and in chapter 26, it theorizes the concept of 'taste'.

Constructivist Implications of the 9.19 Military Implementation Agreement (9.19 군사합의서의 구성주의적 함의 고찰)

  • Lee, Kang Kyong;Seol, Hyeon Ju
    • Convergence Security Journal
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    • v.20 no.2
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    • pp.101-110
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    • 2020
  • Since the third inter-Korean summit, the inter-Korean summit in Pyongyang and the U.S.-North Korea summit in Singapore and Hanoi, denuclearization negotiations are under way that will determine the fate of the Korean Peninsula. However, the negotiations are stalled and some skepticism is expected due to the conflicting U.S.-North Korea stance over the terms of denuclearization. The reason why it is difficult to realize the complete denuclearization of North Korea is that there are a variety of variables such as the traditional security dilemma in Northeast Asia, the hegemonic competition between the U.S. and China, and the formation of a new cold-war system. At a turning point when three inter-Korean summits and three U.S.-North Korea summits were held in the wake of the 2018 PyeongChang Winter Olympics, North Korea's complete denuclearization has become a must-do historical task for Northeast Asia and world peace beyond the Korean Peninsula. In this sense, the inter-Korean summit in Pyongyang is seen as a historic occasion for presenting a new milestone for the denuclearization of North Korea and the development of inter-Korean relations through the 9.19 Pyongyang Joint Declaration and the Military Agreement. Meanwhile, Constructivism, which has become the main paradigm of international political theory, presents the view that ideological variables such as ideology, history and culture define material factors, identity and interests of state actors, and that the structure of international relations can be changed through interaction. In this study, the historical meaning of the 9.19 Pyongyang Declaration, which is now past its first anniversary, was considered from a constructivist perspective. To this end, the development process of constructivism theory and analysis model and the development process of inter-Korean relations were briefly reviewed, and the military implications of the 9.19 Military Agreement were presented.

Overcoming Langage Barrier by Korean Nurses in U.S. Hospital Settings (한국간호사들이 경험한 미국병원에서의 언어장애 극복 과정)

  • 이명선
    • Journal of Korean Academy of Nursing
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    • v.26 no.2
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    • pp.483-496
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    • 1996
  • The purpose of this study was to describe how Korean nurses overcome the language barrier while working in the U.S. hospital settings. Twelve Korean nurses living in New York metropolitan area were asked open-ended, descriptive questions to collect the data. The interviews were done in Korean. All interviews were audiotaped under the permission of the participants and were transcribed verbatim. The data were analyzed using grounded theory analysis. The research process consisted of two phases. In the first phase 8 Korean nurses were interviewed and analyzed. In the second phase, further data were collected to verify categories and working hypotheses that were emerged from the first phase. The results of this study show that all Korean nurses experienced severe psychological stress such as confusion, anxiety, frustration, loss of self-confidence, embarrassment, guilt, depression, anger, and fear. Among the mode of communication such as listening, speaking, leading, and writing, they had the most difficulty in speaking. Speaking ability was especially important for them because of the emphasis of individualism and self-defense in the U.S. Among the verbal communication modes, non-face-to-face communications such as phone conversation and body language were the most difficu1t for them to overcome. It took at least 2 years for the participants to initially overcome the language barrier in U.S. hospitals. After 2-5 years they began to feel comfortable even in non-face-to-face communication. They could actively search for the better place to work after 5 years. They finally felt comfortable in English and in their job almost after 10 years. The factors that influenced the English improvement were ‘the years of clinical experience in Korea’, ‘the decade they came to the U.S.’ ‘coming to U.S. alone or with other Korean nurses’, ‘racial homogeneity or heterogeneity of the working unit’, and ‘the degree of social support’. The strategies Korean nurses used to overcome the language barrier included depending on the written communication, using ‘nunchi’, working and studying hard, and establishing good interpersonal relationships with co-workers. They also employed assertive behavior of the U.S., such as using more explicit verbal language and employing smiles and eye contact with others during the conversation. The results of the study may help Korean nurses and nursing students who try to work in U.S. hospital settings by understanding problems other Korean nurses faced, factors that influenced their English improvement, and strategies they used. They may also help U.S. nurses and administrators in developing and implementing efficient programs for newly employed Korean nurses by understanding major problems and feelings the Korean nurses experienced and strategies they used to overcome the language barriers.

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Nonlinear Relationship Between Technological Entrepreneurship and National Competitiveness: The Moderation Effect of Innovation-driven Economy

  • Yang, Seung-Lin;Kim, Yong-Shin;Chung, Doohee
    • Journal of Technology Innovation
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    • v.27 no.3
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    • pp.113-142
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    • 2019
  • Based on the Knowledge Spillover Theory of Entrepreneurship, this study analyzes the relationship between technological entrepreneurship and national competitiveness. It also analyzes how innovation-driven economy moderates this relationship. Using data on technological entrepreneurship, national competitiveness indexes and economy development stages from 83 countries over 2011 to 2014, this study finds that a ratio of technology-based start-ups in a country has a U-shaped relationship with national competitiveness. this study also finds that countries that are in the innovation-driven economy strengthen this relationship. This finding shows that a higher ratio of technology-based start-ups of a country does not have unconditional positive effects on national competitiveness, thus, related environments and conditions should be elaborately matched. In particular, this finding also implies that policies related to technology-based start-ups should have a proper fit with the level of economic development of the country so that the positive effects of technological entrepreneurship on national competitiveness can be strengthened.

Incorporating Climate Change Scenarios into Water Resources Management (기후 변화를 고려한 수자원 관리 기법)

  • Kim, Yeong-O
    • Journal of Korea Water Resources Association
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    • v.31 no.4
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    • pp.407-413
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    • 1998
  • This study reviewed the recent studies for the climate change impact on water resource systems and applied one of the techniques to a real reservoir system - the Skagit hydropower system in U.S.A. The technique assumed that the climate change results in ±5% change in monthly average and/or standard deviation of the observed inflows for the Skagit system. For each case of the altered average and standard deviation, an optimal operating policy was derived using s SDP(Stochastic Dynamic Programming) model and compared with the operating policy for the non-climate change case. The results showed that the oparating policy of the Skagit system is more sensitive to the change in the streamflow average than that in the streamflow standard deviation. The derived operating policies were also simulated using the synthetic streamflow scenarios and their average annual gains were compared as a performance index. To choose the best operating policy among the derived policies, a Bayesian decision strategy was also presented with an example. Keywords : climate change, reservoir operating policy, stochastic dynamic programming, Bayesian decision theory.

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