• 설비공학논문집
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• 제29권7호
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• pp.366-372
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• 2017

The objective of this study was to characterize Waveguide-Blow-Cutoff (WBC) array for Electromagnetic Pulse (EMP) shield in air duct or water pipe, the typical pathway of pulse in indoor space with critical electronic device. A numerical investigation with three different WBC designs (circular, rectangular, and hexagonal or honeycomb) was conducted to satisfy recommended shielding effectiveness (SE) levels from 80 dB to 140 dB. Pressure drop between upstream and downstream of EMP shields based on WBC arrays was also investigated to understand air flow feature in air duct of HVAC system. Results showed that honeycomb geometry outperformed other shapes in terms of reducing the depth of EMP shield, thus providing better air flow in duct path with lower local loss coefficient in HVAC system under SE requirements.

• 전자공학회논문지B
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• 제29B권10호
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• pp.27-36
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• 1992

This paper proposes a numerical method of motion planning for manipulators using Foruier series. For a redundant manipulator, we predetermine the trajectories of redundant joints in terms of the Nth partial sum of the fourier series. then the optimal coefficients of the fourier series are searched by the Powell's method. For a nonredundant or redundant manipulator, CS02T-continuous smooth joint trajectory for a point-to-point task can be obtained while considering the frequency response. We apply the proposed method to the 3-link planar manipulator and the PUMA 560 manipulator. To show the validity of the proposed method, we analyze solutions by the Fast Fourier Transform (FFT). Also, several features are discussed to obtain an optimal solution.

• Nuclear Engineering and Technology
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• 제49권1호
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• pp.216-223
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• 2017

In this work, linear and mass attenuation coefficients, effective atomic number and electron density, mean free paths, and half value layer and $10^{th}$ value layer values of barium-bismuth-borosilicate glasses were obtained for 662 keV, 1,173 keV, and 1,332 keV gamma ray energies using MCNP-4C code and XCOM program. Then obtained data were compared with available experimental data. The MCNP-4C code and XCOM program results were in good agreement with the experimental data. Barium-bismuth-borosilicate glasses have good gamma ray shielding properties from the shielding point of view.

• Bulletin of the Korean Chemical Society
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• 제21권12호
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• pp.1227-1232
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• 2000

Near the conical intersection for the 1,2 $^{2}A'$ states of $H_3$ the derivative coupling vector is calculated and analyzed on the plane of internal coordinates, (U,V) or its polar coordinates $(S{\theta})$, based on the squares of the internuclear distances. It is shown that in the vicinity of the conical intersection the derivative coupling vector behaves like ${\theta}/2S$, which is responsible for the sign changes of the real-valued electronic wave function when the nuclear configuration traverses a closed path enclosing a conical intersection. The analytic property of the wave functions is studied and especially the observation of the sign change in the configuration state function (CSF) coefficients of the real-valued electronic wave functions is demonstrated.

• 한국산학기술학회논문지
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• 제19권4호
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• pp.317-328
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• 2018

본 연구에서는 창극공연의 서비스 품질이 공연경험속성 및 관객만족에 미치는 영향을 검증하고, 이 과정에서 서비스 가치 및 전통이미지의 매개효과를 검증하였다. 본 연구의 대상은 서울 지역에서 10월 중 공연된 창극공연을 유료관람한 성인 남녀 211명으로서, 수집된 자료를 이용하여 공분산구조분석을 통해 얻은 경로계수로 모형과 가설 검정을 실시하였다. 검증결과, 관객이 지각하는 창극공연 서비스품질의 공연프로그램 품질, 물리적환경 품질, 상호작용 품질은 공연경험속성에 각각 통계학적으로 유의하게 정(+)의 관계를 보였다. 공연경험속성과 서비스가치, 공연경험속성과 전통이미지 간의 경로계수도 각각 통계학적으로 유의하게 정(+)의 관계를 보였다. 그리고 공연경험속성과 관객만족 간의 경로계수는 정(+)의 관계를 보였고, 서비스가치와 전통이미지, 서비스가치와 관객만족, 전통이미지와 관객만족 간의 경로계수도 각각 통계학적으로 유의하게 정(+)의 관계를 보였다. 결국 본 연구의 모든 가설은 채택되었으며, 본 연구의 결과는 창극공연의 대중화와 현대화, 공연예술산업 차원의 마케팅전략에 있어서, 그 공연 서비스 품질과 경험속성을 반영하여, 관객의 만족에 미치는 영향을 확인하고, 이 과정에서 서비스 가치와 전통이미지의 역할 및 작용을 검증하였다는데 의의가 있다.

• 한국방재학회 논문집
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• 제11권3호
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• pp.143-150
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• 2011

도시 우수 배수 시스템에서 우수 관거는 개수로 흐름 상태로 가정하여 설계되었기 때문에 맨홀에서의 에너지 손실은 일반적으로 중요하게 고려되지 않았다. 그러나 과부하흐름에서 에너지 손실은 관거의 배수능력을 저하시켜 도심지역의 침수피해를 가중시키는 요인이 된다. 그러므로 과부하 사각형 맨홀 내에서의 수두 손실을 분석할 필요가 있다. 본 연구에서는 FLUENT 6.3 모형을 이용하여 과부하 사각형 합류맨홀에서의 흐름특성을 모의하고 맨홀 내 손실수두의 변화를 계산하여 손실계수를 산정하였다. 또한 실험결과와 수치모의 결과를 비교 및 분석하여 사각형 맨홀에서의 손실계수 산정에 FLUENT 6.3모형의 적용성을 확인하였다. 맨홀 폭(B)과 연결관경(d)의 비(B/d)에 따른 손실계수를 산정하였다. B/d가 증가할수록 사각형 합류 맨홀에서의 손실계수는 증가하였다. 중간 단차 맨홀에서 단차 변화에 따른 손실계수의 변화를 산정하였다. 단차가 5 cm이상 증가하면 맨홀 내 수심과 손실계수가 점진적으로 증가하였으므로 중간 맨홀에서의 적정 단차는 5 cm로 판단된다. 따라서 우수 관거 시스템의 여러 형태의 사각형 맨홀에서의 흐름의 변화 및 손실계수를 예측할 때, Fluent 6.3 모형은 사용 가능하리라 판단된다.

• Current Research on Agriculture and Life Sciences
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• 제1권
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• pp.27-34
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• 1983

소맥(小麥) $F_2$집단(集團)에 있어서 조숙(早熟) 다수성(多收性) 계통(系統)의 효율적(效率的)인 선발(選拔)에 관(關)한 기초자료(基礎資料)를 얻고자 중숙(中熟)${\times}$조숙(早熟)(올밀/새밀), 만숙${\times}$중숙(中熟)(Naphal/청계밀) 두 조합(組合)을 공시(供試)하여 $F_2$집단(集團)의 유전적(遺傳的) 변이(變異)를 조사(調査)하고 경로분석(徑路分析)을 한바 얻어진 결과(結果)는 다음과 같다. 유전변이계수(遺傳變異係數)는 올밀${\times}$새밀 조합(組合)에서는 수획지수(收獲指數), 립수(粒數), 수량(收量), 간장(稈長)의 순(順)으로, Naphal${\times}$청계밀 조합(組合)에서는 수획지수(收獲指數), 간장(稈長), 1,000 립중(粒重)의 순(順)으로 높았다. 유전력(遺傳力)(협의(狹意))은 양조합(兩組合)에서 출수기(出穗期), 성숙기(成熟期), 간장(稈長), 수획지수(收獲指數)가 높았고(0.525~0.808) 립수(粒數), 수량(收量)은 낮았다. 유전획득량(遺傳獲得量)(%)은 출수기(出穗期), 성숙기(成熟期)가 양조합(兩組合)에서 모두 높았고 수량(收量)은 낮았다. 1,000립중(粒重)의 유전획득량(遺傳獲得量)(%)은 Naphal${\times}$청계밀 조합(組合)에서는 높게 나타났다. 수량(收量)과 수수(穗數) 및 립수(粒數)와는 높은 정(正)의 유의상관(有意相關)을 보였고 수량(收量)에 대(對)한 직접효과(直接效果)는 수수(穗數)가 가장 컸고 다음은 립수(粒數)였다.

• 한국산림과학회지
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• 제26권1호
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• pp.13-18
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• 1975

본시험(本試驗)은 죽간재적(竹稈材積)에 영향(影響)하는 형질(形質)을 정확(正確)하게 파악(把握)하기 위(爲)하여 계획(計劃)되었다. 그리고 왕대의 수개형질상호간(數個形質相互間)의 표현형상관(表現型相關), 유전상관(遺傳相關) 및 환경상관(環境相關)을 구명(究明)하고져 공분산분석(共分散分析) 되었으며 Dewey and Lu의 편회귀분석법(偏回歸分析法)으로 각형질(各形質)이 죽간재적(竹稈材積)에 미치는 효과(効果) 즉(即) 경로계수(經路係數)를 산출(算出)하였다. 조사형질(調査形質)은 흉고직경(胸高直徑), 죽간고(竹稈高), 지상고(枝上高), 지하경(地下莖), 절수(節數), 근원직경(根元直徑) 및 죽간재적(竹稈材積)이며 각(各) 형질(形質)의 평균치(平均値), 표준오차(標準誤差), 분산(分散) 및 표준편차(標準偏差)는 제(第)1표(表)와 같고 7개형간(個形間)의 표현형(表現型), 유전(遺傳) 및 환경상관(環境相關)을 분산분석(分散分析)한 결과(結果)는 제(第)2표(表)와 같이 계통간(系統間)에는 고도(高度)의 유의성(有意性)이 인정(認定)되었으나 몇몇 반복간(反覆間)에는 유의성(有意性)이 인정(認定)되지 않았다. 각(各) 형질(形質)의 유전력(遺傳力)을 추정(推定)한바 흉고직경(胸高直徑)과 근원직경(根元直徑)은 유전력(遺傳力)이 높고 기타형질(其他形質)의 유전력(遺傳力)은 제(第)4표(表)에서와 같이 보다 낮으며 환경상관(環境相關)은 표현형상관(表現型相關), 유전상관(遺傳相關)보다 전체적(全體的)으로 낮다. 그리고 죽간재적(竹稈材積)에 대(對)하여 근원직경(根元直徑)과 흉고직경(胸高直徑)은 높은 상관관계(相關關係)를 나타내었다. 형질별(形質別) 상관관계(相關關係), 경로계수(經路係數) 및 죽간재적(竹稈材積)에 미치는 직접(直接), 간접효과(間接効果)는 도표(圖表) 1과 제(第)5표(表)에서 볼 수 있으며 결과적(結果的)으로 본시험(本試驗)에서는 죽간재적수량(竹稈材積收量)은 근원직경(根元直徑)과 흉고직경(胸高直徑)에 의(依)하여 좌우(左右)될 수 있다는 것을 알았다.

• KSTLE International Journal
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• 제7권2호
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• pp.27-34
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• 2006

Knudsen number is the ratio of molecular mean free path versus mm thickness and the criterion to determine the flow form. When its value is lower than 0.01, the flow can be assumed to has no slip boundary condition. And in the case that the value is between 0.01 and 10, then the flow has slip boundary condition at both the adjacent walls. The condition of the air flow between the rotating journal and top foil in the air foil bearing is determined by the rotating speed and load, and the Knudsen number is also varied by those values. Because the molecular mean free path is variable to the pressure and temperature, more exact formulation is necessary to understand and analyze the flow regime. In this study, the analysis considering Knudsen number formulated with those variables (pressure, temperature and mm thickness) was executed. The approximate value was examined using the equation to confirm whether the flow has the slip or no-slip boundary condition. From the analytic investigation, it was decided to range approximately 0.01 to 1.0 and the flow can be supposed to have the slip boundary condition. Under the condition of the slip flow, the static characteristics of the air foil bearing were examined using modified Reynolds equations. The results were compared with those considering no slip condition. It shows that the slip condition makes the flow decelerates and the load carrying capacity decreases compared with no slip condition. And as the bearing number and eccentricity ratio increase, the load carrying capacity also increased at both the cases. From this result, it can be supposed that the bearing torque also increases. In the analysis of the dynamic characteristics, the perturbed Knudsen number was taken into consideration. Because the Knudsen number is expressed as the terms of each variable, the perturbed equation can be simply derived. The results of both cases considering and not considering Knudsen number were compared each other. In the case of the direct terms of the stiffness and damping coefficients, the difference between both cases was little and increased as the bearing number and eccentricity ratio increased. And the cross terms have less or more differences.

• Journal of Korea Trade
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• 제23권6호
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• pp.33-51
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• 2019

Purpose - The purpose of this study is to provide practical implications for Korean companies searching for new market opportunities. From the experimental analysis, the impact of country image on product-country image and purchase intention of Korean products are measured. In addition, this study disaggregates the impacts of country image and product-country image and purchase intention among ethnic groups in South Africa for searching further useful implications. Design/methodology - To examine South African consumers' country image and product-country image towards Korean products, data were collected between June and July 2019 through an online questionnaire, and 335 questionnaires were used for analysis. Firstly, the multivariate analysis was conducted to examine the general tendency of South African consumers' perceptions of country image to Korea, product-country image, and purchase intention among three ethnic group consumers. Then in order to verify the country image model and hypotheses of the study, we analyzed the structural models for each of the three ethnic groups and compared the sizes of the path coefficients for each groups. To compare the difference of path coefficients across ethnic groups, configural invariance, metric invariance, and scalar invariance tests were conducted sequentially. Findings - In the black and white ethnic groups, the country image had a statistically significant impact on product-country image, but it did not affect the purchase intention to Korean products. The product-country image showed a statistically significant impact on the purchase intention to Korean products in both ethnic group. However, in the coloured ethnic group consumer, the country image had a significant effect on the product-country image, but it did not affect the purchase intention of Korean products. In addition, the product-country image did not have a significant influence on the purchase intention of coloured ethnic group consumers unlike black and white ethnic group consumers. The results of this study suggest that even though differences in terms of the impact of CoI on PCI and PI were investigated for the sample of white, coloured, and black respondents, the groups seemed to respond in a reasonably comparable manner. Originality/value - South Africa occupies more than 20% of Africa's total GDP in sub-Saharan Africa and is a hub for Southern African logistics as a hub for Korean companies to enter Africa. However, it is rare to find a study focused on the determinants of consumer behavior in South Africa. In particular, this study disaggregates the impacts of country image and product-country image on consumer behavior across ethnic groups in South Africa. Therefore, this study could provide practical implications for Korean firms which desire to diversify their export markets and pioneer future markets.