• 공학교육연구
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• 제3권1호
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• pp.42-52
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• 2000

공장 생산설비 자동화 분야는 다양한 기반기술을 응용하는 분야이다. 중소기업의 입장에서 보면, 공장 생산설비 자동화분야와 관련된 많은 애로 사항이 있다. 본 연구에서는 공장 생산설비 자동화 인력의 효율적인 양성을 위하여 자동화 관련분야의 세부과제들을 현장중심으로 도출하여 현장적응력을 향상시킬 수 있는 교육모형을 제시하고 제작하였다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2004년도 춘계 학술대회논문집
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• pp.183-189
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• 2004

The flow and the heat transfer about the cross-flow fin-tube heat exchanger in an out-door unit of a heat pump system has been numerically Investigated. Using the general purpose analysis code, FLUENT, the Navier-Stokes equations and the energy equation are solved for the three dimensional computation domain that encompasses multiple rows of the fin-tube. The temperature on the fin and tube surface is assumed constant but compensated later through the fin efficiency when predicting the heat-transfer rate. The contact resistance is also taken into consideration. The flow and temperature fields for a wide range of inlet velocity and fin-tube arrangements are examined and the results are presented in the paper. The details of the flow are very well captured and the heat transfer rate for a range of inlet velocity is in excellent agreement with the measured data. The flow solution provides the effective permeability and the inertial resistance factor of the heat exchanger if the exchanger were to be approximated by the porous medium. This information is essential in carrying out the global flow field calculation which, in turn, provides the inlet velocity lot the microscopic temperature-field calculation of the heat exchanger unit.

• 지식경영연구
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• 제17권4호
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• pp.77-104
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• 2016

The effective management of R&D employees is critical for a small or medium sized firm's sustainable growth. R&D employees have professional skills and choose expertise-oriented or management-oriented careers in the process of organizational socialization. This study synthetically verifies the direct and indirect effects of R&D employees' social network and self-esteem on their career orientation by organizational commitment based on social network theory and social recognition theory. The research model has been analyzed through structural equation modeling using survey responses from 220 R&D employees at small- and medium-sized firms in Korea. The analysis results show that internal network activities have direct and indirect impacts on organizational commitment and career orientation, but external network activities do not have significant effects on self-esteem, organizational commitment, or career orientation. There is no consensus in prior studies on whether expert orientation and management orientation are distinct concepts. In this study, these two types of orientation are verified as distinct concepts. It is also found that R&D employees' internal network activities are significant factors for a company's growth. A company should implement an educational system of roles and duties using which individuals can pursue career progression. In addition, it is necessary to provide career development programs such as job rotation, mentoring, and career counseling.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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• pp.111-111
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• 2003

Green tea have been widely reported as functional foods because of their various bioactivities. In the present study, we used 3T3-Ll cells model of white adipocytes to clarify whether green tea and its main pharmaceutically effective compounds (EGCG, caffeine and theanine) prevent obesity. Cellular viability, glycerol-3-phosphate dehydrogenase activity, glycerol release and HSL mRNA levels were checked. Glycerol release into the medium was significantly increased by the cells treated with green tea extract. Glycerol release into the medium was significantly increased by the cells treated with green tea extract. Caffeine and theanine from green tea showed some level of lipolytic activity, and glycerol-3-phosphate dehydrogenase activity was remarkably decreased by EGCG. These results suggest that green tea has anti-obesity effect through inhibition of adipogenesis and stimulation of lipolysis. Catechins and theanine of green tea might be the factors responsible for the modulation of lipid metabolism and adipocyte differentiation.

• Steel and Composite Structures
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• 제23권6호
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• pp.691-714
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• 2017

Rotating fluid induced vibration and instability of embedded piezoelectric nano-composite separators subjected to magnetic and electric fields is the main contribution of present work. The separator is modeled with cylindrical shell element and the structural damping effects are considered by Kelvin-Voigt model. Single-walled carbon nanotubes (SWCNTs) are used as reinforcement and effective material properties are obtained by mixture rule. The perturbation velocity potential in conjunction with the linearized Bernoulli formula is used for describing the rotating fluid motion. The orthotropic surrounding elastic medium is considered by spring, damper and shear constants. The governing equations are derived on the bases of classical shell theory (CST), first order shear deformation theory (FSDT) and sinusoidal shear deformation theory (SSDT). The nonlinear frequency and critical angular fluid velocity are calculated by differential quadrature method (DQM). The detailed parametric study is conducted, focusing on the combined effects of the external voltage, magnetic field, visco-Pasternak foundation, structural damping and volume percent of SWCNTs on the stability of structure. The numerical results are validated with other published works as well as comparing results obtained by three theories. Numerical results indicate that with increasing volume fraction of SWCNTs, the frequency and critical angular fluid velocity are increased.

• 한국육종학회지
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• 제42권4호
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• pp.351-356
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• 2010

Brachypodium distachyon is rapidly emerged in biological study and has been currently used as a model system for genetics and functional studies for crop improvement and biofuel production. Phosphinothricin (PPT) has been widely used as a selectable agent, which raises ammonium content and induces toxicity in non-transformed plant cells. However PPT selection is not much effective on Brachypodium callus consequently reducing transformation efficiency. In order to identify the efficient conditions of PPT selection, calli obtained from mature seeds of Brachypodium (PI 254867) were cultured on the callus inducing medium (CIM) or regeneration medium (ReM) containing serial dilutions of the PPT (0, 2, 5, 10, and 15 mg/l) in dark or light condition. Callus growth and ammonium content of each treatment were measured 2 weeks after the treatment. Although callus growth and ammonium content did not show much difference in CIM, slow callus growth and increased ammonium accumulation were found in ReM. No significant difference of ammonium accumulation in response to PPT was found between dark and light conditions. In order to identify major factors affecting increased ammonium accumulation, callus was cultured on the media in combined with phytohormones (2,4-D or kinetin) and carbon sources (sucrose or maltose) containing with PPT (5 mg/l). The highest ammonium content in callus was found in the kinetin and maltose media.

• 스마트미디어저널
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• 제12권9호
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• pp.124-133
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• 2023

오늘날의 우리나라는 급격한 경제적 성장과 더불어 국제사회의 일원으로서 문화, 경제, 사회를 함께 공유하고 있다. 특히 2000년대 들어서 지역사회 문화 발전의 노력과 방법으로 지역문화 공연장 건립을 추진해 왔다. 그 결과 많은 자치단체에 중규모 이상의 공연장을 건립하여 시민들의 만족과 관람객 유치를 통해 양적인 증가와 질적인 효과를 동시에 이루는 성과를 만들게 되었다. 하지만 최근 들어 빈번히 발생 되는 재해 및 재난 상황에 많은 관람객이 동 시간대에 사용하는 공간의 안전과 효과적인 피난 계획이 적용되고 있는지에 대한 분석을 본 연구에서 진행하고자 하며, 연구의 내용으로 관람자들의 대피 시뮬레이션을 통하여 공간의 문제점을 파악하고 향후 공연장 설계 시 적용될 수 있는 기초적 자료를 제공하고자 한다.

• 한국농공학회지
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• 제29권4호
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• pp.59-72
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• 1987

Although long-term runoff analysis is important as much as flood analysis in the design of water works, the technological level of the former is relatively lower than that of the latter. In this respect, the precise estimation model for the volume of successive runoff should he developed as soon as possible. Up to now, in Korea, Gajiyama's formula has been widely used in long-term runoff analysis, which has many problems in applying in real situation. On the other hand, in flood analysis, unit hydrograph method has been exclusively used. Therefore, this study aims at trying to apply unit hydrograph method in long-term runoff analysis for the betterment of its estimation. Four test catchment areas were selected ; Maesan area in Namlum river as a representative area of Han river system, Cheongju area in Musim river as one of Geum river system, Hwasun area in Hwasun river as one of Yongsan river system, and Supyung area in Geum river as one of Nakdong river system. In the analysis of unit hydrograph, seperation of effective rainfall was carried out firstly. Considering that effective rainfall and moisture condition of catchrnent area are inside and outside of a phenomenon respectively and the latter is not considered in the analysis, Initial base flow(qb)was selected as an index of moisture condition. At the same time, basic equation(Eq.7) was established, in which qb can take a role as a parameter in relating between cumulative rainfall(P) and cumulative loss of rainfall(Ld). Based on the above equation, computer program for estimation model of qbwas seperately developed according to the range of qb, Developed model was applied to measured hydrographs and hyetographs for total 10 years in 4 test areas and effective rainfall was estimated. Estimation precision of model was checked as shown in Tab- 6 and Fig.8. In the next stage, based on the estimated effective rainfall(R) and runoff(Qd), a runoff distribution ratio was calculated for each teat area using by computerised least square method and used in making unit hydrographs in each test area. Significance of induced hydrographs was tested by checking the relative errors between estimated and measured runoff volume(Tab-9, 10). According to the results, runoff estimation error by unit hydrograph itself was merely 2 or 3 %, but other 2 or 3 % of error proved to be transferred error in the seperation of effective rainfall. In this study, special attentioning point is that, in spite of different river systems and forest conditions of test areas, standardized unit hydrographs for them have very similar curve shape, which can be explained by having similar catchinent characteristics such as stream length, catchinent area, slope, and vegetation intensity. That fact should be treated as important factor ingeneralization of unit hydrograph method.

• 한국전자거래학회지
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• 제24권4호
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• pp.135-149
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• 2019

매출채권보험은 거래상대방의 채무불이행으로 인한 중소기업의 손실 발생위험을 제거하는데 매우 효과적인 수단이며, 기업의 연쇄도산을 막음으로써 경제적으로 국내 중소기업을 보호하는 제도이다. 하지만 이러한 유용성에도 불구하고 중소기업들은 매출채권의 소유권 확인 및 이전 문제, 가입의 복잡성 등으로 현재 활용도가 저조한 실정이다. 이에 본 연구는 매출채권보험의 활성화를 위하여 프라이빗 블록체인(Private blockchain) 기반의 매출채권보험 플랫폼 구축을 제안하였다. 제안된 매출채권보험 플랫폼은 보험 가입의 편의성과 신뢰성 검증에 대한 기존 문제를 해결할 수 있을 것이다. 또한, 블록체인 기술을 기반으로 신속한 거래속도를 확보하고, 네트워크 확장의 용이성과 접근 관리를 통해 중소기업을 위한 매출채권보험 가입 활성화에 도움을 될 것으로 기대한다.

• 디지털융복합연구
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• 제15권5호
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• pp.107-115
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• 2017

최근 스마트 팩토리에 대한 관심이 크게 증가하고 있다. 그러나, 이러한 높은 관심에도 불구하고 정작 어떻게 스마트 팩토리를 구축해야 하는지에 대한 구체적인 가이드라인이 없는 실정이다. 또한 기존의 사례들은 주로 독일을 중심으로한 해외 사례로서 국내에 그대로 적용하기에는 다소의 괴리감이 존재한다. 또한 스마트 팩토리는 기업의 규모와 성격에 따라 구축방식이 상이할 수 있다. 이러한 상황에서 본 연구는 국내 대 중 소기업들을 대상으로 스마트 팩토리 성공구축 사례들을 분석 하였다. 사례분석 결과, 대기업의 경우 일부공장을 대상으로 시범적으로 스마트팩토리를 구축한 후 성공적으로 평가될 시 전체공장으로 확대시키는 전략이 효과적이다. 중소기업의 경우, 낮은 수준의 스마트팩토리 구축레벨에서 높은 수준의 구축레벨로 업그레이드하는 것이 효과적이다. 말하자면 본 연구에서 실시한 스마트 팩토리 성공사례 분석을 통해, 기업들에게 성공적 구축을 위한 실제적인 가이드라인을 제공하고자 한다. 아울러, 본 연구를 통해 제시된 구축전략들은 향후 스마트 팩토리 구축을 고려하고 있는 기업과 정부에게 중요한 함의를 제시하고자 한다.