• Journal of the Korean Geotechnical Society
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• v.40 no.2
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• pp.29-40
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• 2024

This study aimed to evaluate the swelling behavior characteristics of KJ-II buffer blocks by performing numerical analysis of swelling pressure measurement experiments using the nonlinear elasticity model of COMSOL Multiphysics. The analysis was conducted under boundary conditions that included isotropic constraints and water injection pressure, mirroring the experimental settings. Validation of the numerical model was achieved by comparing its outputs with experimental results. The validated model was then used to simulate swelling deformations under unconfined conditions and to analyze swelling pressure as influenced by dry density and the geometric shape of the buffer material. The results accurately represented the swelling deformation observed during the saturation process and demonstrated that swelling pressure increases with higher dry density. Moreover, simulations concerning the geometric shape of the buffer material indicated a markedly faster rate of pressure increase in U-shaped samples compared to cylindrical ones. Analysis suggested that stress manifested preemptively near the internal edges of U-shaped samples during saturation. To enhance the simulation's fidelity to actual buffer material behavior, further refinement of the analysis model using a nonlinear elasticity model is recommended.

• Journal of Korea Technology Innovation Society
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• v.19 no.3
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• pp.417-438
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• 2016

The choice of SMEs between standardization and R&D is one of the strategies of building capabilities for achieving competitive advantages under the liabilities of newness and smallness. This paper provides empirical evidence of Korean SMEs choice between standardization and R&D. We hypothesize two possible impacts of standardization intensity on sales performance; a positive linear and a U-shaped relationship. The analysis of data on 821 Korean SMEs from information and technology, and electricity and electronics industries in 2013 shows an U-shaped relationship between relative standardization intensity over R&D and sales performance.

• The Research Journal of the Costume Culture
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• v.12 no.6 s.53
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• pp.1021-1030
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• 2004

The purpose of this study was to develop and make the head form by setting the region of the head for detailed measurement of the head to make the type of closely fit hat and typifying the head form of Korean women's with each region of the head based on the measurements of each region of the head according characteristics. A total of 285 Korean women's in the age group of 18 to 35 years old. It were measured through the direct measurement method by selecting 67 measurement items. As a result of the findings obtained from cluster analysis could be classified into 3 type. Type 1($46\%$) is U-shaped form, that is high in head height on sides and circumference is smallest, whose facial region and occiput is flattest of three types. Type 2($22.4\%$) is inverted triangle form, that is flat in head ridge, low in head height on sides and wide in the frontal width. Type 3($31.6\%$) is oval form, that is largest in size, has the projected occiput and is of three-dimensional form.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.10a
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• pp.132-136
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• 2004

본 연구는 근육 및 지방세포 분화에 관여하는 leptin, MYF5 및 H-FABP의 3개 기능성 후보 유전자가 한우의 도체특성 및 육질에 미치는 영향을 분석하기 위하여 이들 유전자의 PCR-RFLP marker와 도체형질과의 관련성을 분석하였다. Leptin, MYF5 및 H-FABP 유전자에서 AA, AB 및 BB 3종류의 RFLP 유전자형이 각각 검출되었고 A와 B 대립유전자 빈도는 각각 0.57과 0.43, 0.61과 0.39 그리고 0.90과 0.10으로 추정되었다. 육질 등급에 따라 고급육과 저급육으로 분리 선발한 두 그룹간의 대립유전자 출현빈도를 비교한 결과 leptin과 MYF5 유전자에서 각각 통계적 유의차(P< .05)가 인정되었다. 또한 각 후보유전자의 RFLP marker 유전자형이 도체형질에 미치는 효과를 분석한 결과 leptin 유전자는 등지방 두께 그리고 MYF5유전자는 배장근 단면적에 각각 유의적인 영향(P< .05)을 미치는 것으로 분석되었다. 그러나 H-FABP 유전자는 도체형질들과 유의성이 인정되지 않았다. 따라서, leptin과 MYF5 유전자는 한우의 도체특성 및 육질 개선을 위한 DNA marker로 이용 가능할 것으로 사료된다.

• Journal of the Economic Geographical Society of Korea
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• v.25 no.4
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• pp.629-640
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• 2022

This study analyzed the relationship between local government size and regional economic growth using regional data from 2002 to 2020. By dividing local government expenditure into social development expenditure and economic development expenditure, economic growth and the inverted U-shaped Armey curve were verified, and the optimal size of local government expenditure was examined. In particular, the AMG estimation method considering the cross-sectional dependence and regional heterogeneity existing in the panel data was utilized. As a result of the analysis, it was found that there was an inverted U-shaped relationship between local fiscal expenditure and regional economic growth. When the proportion of total local fiscal expenditure is 7.63% of GRDP and social development expenditure is 3.45%, it is found that the optimal size of expenditure can maximize the regional economic growth rate. Local governments should increase the effectiveness of public expenditure policies by considering these points.

• Journal of Korea Technology Innovation Society
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• v.21 no.1
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• pp.454-490
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• 2018

This paper examined the nonlinear relationships between external knowledge sources and the innovation performance of SMEs (small and medium-sized enterprises). Using 3,218 firm-year panel data in South Korea, this study found that increasing the number of external knowledge channels out of the value chain increases radical innovation. Meanwhile, increasing the number of external knowledge channels within the value chain increases the incremental innovation. Further, the external sources of knowledge both out of and in the value chain had inverted U-shaped relationships on radical and incremental innovation respectively. This finding implies that a mechanism of diminishing returns works in the relationship between the external sources of knowledge and innovation. The study also identified the synergistic effects between the external sources of knowledge out of the value chain and within the value chain, and confirmed that the synergistic effects strengthen the linear mechanism between the external sources of knowledge and innovation. In addition, this study found that the sources of knowledge both out of and within the value chain positively moderate the relationships between R&D investment and radical innovation of SMEs.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.319-320
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• 2011

Lax-Wendroff 기법을 기반의 천수방정식에 대한 유한요소 모형을 낙동강 상류부 단호교 지역에 적용하였다. 모형의 검증을 위하여 이동경계에 대한 Thacker (1981)의 정확해와 침수-노출 기법(wet-dry scheme)을 이용한 본 모형의 수치해를 비교하여 대체로 잘 일치함을 알게 되었다. 또한, U자형 만곡부를 포함한 수로의 흐름에 적용하여, 기존의 수리실험 결과, 수치모의 결과와 비교하고, 모형의 적용 가능성을 확인하였다. 낙동강 상류지역에 위치한 단호교 지역에 본 모형을 적용하고, 이를 기존 유한차분법에 의한 수치해와 비교하였다.

• Journal of the Korean Vacuum Society
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• v.4 no.2
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• pp.124-134
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• 1995

포항가속기연구소에서는 PLS 2-GeV 선형가속기 클라이스트론의 교체 및 보수시에 사용하기 위하여, 80 MW급 S-band의 도파관 밸브를 개발중에 있다. PLS형 도파관 밸브는 결합수단 없이 대전력을 전송할 수 있는 구조로 설계되어, 전력전송에 대한 제한을 받지 않는 특징을 갖는다. 본 도파관 밸브의 주요구성부는 밀착구동체를 갖는 U자형 도파관부, 두 개의 H-코너가 부착된 진공함, 그리고 두 개의 Viton O-링이 장착된 진공기밀판으로 이루어져 있다. 시제품용 도파관 밸브의 특성조사 결과, 펄스폭 3.5 $\mu$sec, 반복율 30 Hz에서 65MW의 전력전송을 얻을 수 있었다. 본 논문에서는 PLS도파관 밸브의 설계 개념, 기계적 특성 및 가공의 순으로 자세히 논할 것이며, 또한 현재까지의 실험결과 및 앞으로의 계획에 대하여 보고하기로 한다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.839-840
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• 2015

IPM(Interior Permanent Magnet) 모터는 마그네틱 토크와 릴럭턴스 토크를 이용하는 모터이다. 이런 IPM 모터에 쓰이는 영구 자석 중 희토류 자석은 온도에 취약한 특성이 있어 낮은 온도에 비해 높은 온도에서 더 쉽게 불가역감자가 발생할 수 있다. 또한 페라이트자석에 비해 상대적으로 가격이 비싸 희토류 저감 IPM 모터 개발이 지속적으로 진행되고 있다. 따라서 본 논문에서는 희토류 저감 IPM 동기모터의 영구자석 위치를 변화한 3가지 U자형 2층 IPM 모터 모델을 선정하여 회전자 전류의 크기 및 위상 그리고 약자속 제어를 고려한 불가역 감자 특성을 비교 및 분석하였다. 이렇게 분석한 결과를 바탕으로 IPM 설계 시 불가역감자에 강인한 설계 방법에 대하여 고찰하였다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.1 s.232
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• pp.35-45
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• 2005

TR-E2 configuration designed by Bell Textron was tested in KARI 1-m wind tunnel. To explore aerodynamic characteristics for the given configuration, a $12\%$ scaled model was fabricated and tested. Wind tunnel test for TR-E2 had been performed by changing the incidence angles of wing and deflection angles of control surfaces. Test result showed that the lower wing incidence angle has more favorable lift to drag ratio compared with original design. Longitudinal and directional characteristics of TR-E2 were found to be stable for the pitch and yaw motions. However, the lateral stability of TR-E2 is not stable for certain control surface deflection.