• 설비공학논문집
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• 제10권1호
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• pp.95-107
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• 1998

Natural convection and radiation heat transfer in a square enclosure containing absorbing, emitting, and isotopically scattering(participating) media is studied numerically using the finite volume method. Various numerical methods are employed to analyze the radiative heat transfer. However, it is very difficult to choose the proper method. In present study, a finite volume method(FVM) and a discrete ordinates method(DOM) are compared in rectangular enclosure. The SIMPLER algorithm is used to solve the momentum and energy equations. Thermal and flow characteristics are investigated according to the variation of radiation parameters such as optical thickness and scattering albedo. The result shows that the accuracy and the computing time of FVM are better than those of DOM in regular geometry.

• 대한기계학회논문집
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• 제16권10호
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• pp.1955-1962
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• 1992

본 연구에서는 무한 원형관 안의 복사에 참여하는 참여가스에 면을 도입시키 면, 참여가스로부터 원형관 벽면으로의 복사 열유속(radiatve heat flux)이 증진 또는 감소되는 현상을 연구하는 데 있다. 참여가스는 흡수, 방사 특성이 온도와 파장에 변하지 않는 회체가스(gray gas)이거나, 화석 연료 연소시 연소가스의 성분이며, 복사 에 참여하는, 수증기와 이산화탄소의 혼합물이다. 편의상, 이 가스를 실제가스(real gas)라 부르기로 한다.도입면은 동축 무한 원형관(coaxial Infinite cylinder)이다. 참여가스의 성분, 계의 직경, 동축 무한 원형관 사이의 직경비, 면의 방사율, 면과 가 스의 온도가 열전달 증진에 미치는 영향을 연구하고자 한다.

• 경영과학
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• 제32권4호
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• pp.155-173
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• 2015

Koreatech has adopted a long-term co-op program called IPP (Industry Professional Practice) to address problems in higher education of Korea since 2012, but it was anticipated to face many difficulties in implementing the program due to lack of relevant experiences in Korea. In this regard, a performance evaluation scheme was urgently required to judge the effectiveness of the Co-op program and improve the operational efficiency at the same time. This study aimed to develop comprehensive performance evaluation criteria for the co-op programs on the basis of Kirkpatrick's four-level performance evaluation model for training programs, and apply it to a real Co-op operation to test its feasibility. For this purpose, thorough review on the training program evaluation literature and in-depth analyses of overseas cases of co-op performance evaluation were conducted. Then, a set of Co-op performance evaluation criteria was developed and applied to the Koreatech's Co-op operation in 2013. Two Co-op student questionnaire surveys were administered before and after Co-op terms to measure students' reactions to the Co-op program (Level 1) and changes in participating students' attitudes and competencies (Level 2). In addition, employment rates of Co-op participating and non-participating students were compared (Level 4). The analysis findings showed that participating students were quite satisfied with their jobs and companies, and the Co-op program was effective to a certain degree at enhancing non-major competencies and attitudes to occupation of students. Together, the employment rate of Co-op participants, particularly in small- and medium-sized companies, grew significantly in comparison with that of non-participants. In the last part, several directions for improving the effectiveness of the Co-op programs were discussed.

• 대한기계학회논문집B
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• 제25권10호
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• pp.1451-1458
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• 2001

The effects of a specularly reflecting surface on the wall heat flux and medium temperature distribution are studied. The system is an infinite square duct enclosing an absorbing and emitting medium. The walls are opaque, and black or gray. The walls emit diffusely but reflect diffusely or speculary. Heat is transferred by the combined effect of conduction and radiation. The radiative heat transfer is analyzed using direct discrete-ordinates method. The parameters under study are conduction, to radiation parameter, optical depth, wall emissivity, and reflection characteristics. The specular reflection and diffuse reflection show sizeable differences when the conduction to radiation parameter is less than around 0.01. The differences appear only either on the side wall heat flux or on the medium temperature profiles for the range of this study. The differences on the side wall heat flux are observed for optical thickness less than around 0.1 However the differences on the medium temperate profiles are found for optical thickness greater than around 1. The difference increase with increasing reflectance. The specular reflection increases the well heat flux gradient along the side wall.

• 한국전자거래학회지
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• 제3권1호
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• pp.95-115
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• 1998

The growth of the internet shopping mall has led to a critical mass of consumers and firms participating in a global online marketplace. This study is devoted to providing a conceptual framework for describing and analyzing the characteristics of internet shopping mall. We proposed a model which classifies internet shopping mall into four types, including (1) general intermediary (2) general direct-sales (3) specialized intermediary (4) specialized direct-sales. Our framework facilitates greater understanding of the internet shopping mall as commercial medium and allows examination of internet shopping mall in terms of the opportunities and challenges firms facing online business.

• 무역학회지
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• 제44권1호
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• pp.221-235
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• 2019

SMEs are experiencing difficulties in doing sales promotion due to the low awareness of the image of the company and the products produced by them in the global market. Therefore, the Government should seek ways to raise awareness of SMEs' image and products. SMEs have to carry out global innovation activities needed to develop new products or new technologies, but they are exposed to limitations of these innovative activities due to the limit of their available resources. Therefore, as a national project, the Ministry of SMEs and Startups and the Small and Medium Business Corporation are doing project for fostering and constructing global shopping mall (independent mall) so that SMEs can strengthen their global innovation activities. The purpose of this paper is to contribute to succeeding in the project for fostering and constructing global shopping mall (independent mall) by studying the case of Zungle Incorporation which operates a global shopping mall and greatly increases exports by participating in this project, and identifying success factors of Zungle Incorporation in doing this project.

• 한국산업정보학회논문지
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• 제8권4호
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• pp.1-7
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• 2003

본 논문에서는 현재 강원도 중소기업들이 기업경쟁력을 높이기 위해 실시하고 있는 품질경영 방안에 대해 연구하였다. 특히 본 연구에서는 공동기술개발 컨소시엄을 실시하고 있는 중소기업을 대상으로 21세기 일류기업으로 발전해 나가기 위해 기업에서 중점적으로 추진하고 있는 품질 경영 추진방안에 대해 조사하였다. 연구수행에 있어서 지방 중소기업들이 공통적으로 겪고 있는 인력부족 및 자금부족으로 인해 기업에서 중점적으로 관심을 갖고 추진하여야 하는 품질경영 전반에 걸쳐 어려움을 겪고 있는 것으로 나타났다. 21세기 지방소재 중소기업이 일류기업으로 발전하기 위한 방안은 기업 내 인력을 지역 대학과 연계하여 주기적인 교육프로그램을 추진할 필요성이 있으며 기업과 관련된 교수 외부전문가(연구원) 등을 적극적으로 활용하여 기업경쟁력 확보를 위한 경영전략을 모색하고 지속적으로 산$.$학$.$관의 유기적인 시스템을 구축할 필요성이 있다. 본 연구의 한계는 조사 대상기업이 강원도에 위치한 제조기업 중에서 컨소시엄 참여기업이기 때문에 현황과 추진활동 차이에 따른 결과의 해석을 일반화하기에는 약간 무리가 있으며, 향후의 연구에서는 컨소시엄 참여기업 만이 아닌 강원도 소재 제조기업 중에서 표본을 추출하거나, 전수조사를 실시하여보다 세밀한 분석이 실시되어질 필요가 있을 것이다.

• 한국정보통신학회논문지
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• 제25권9호
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• pp.1234-1243
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• 2021

본 연구에서는 한국 방산분야에서 정부분야 경쟁력 향상을 위하여 미국의 FMS 제도를 모델로 하여 한국형 G to G 방위산업협력을 위한 국제국방산업협력제도 도입 시, 국방산업협력국가 확산이 어떻게 이루어질 것인지를 Bass 모델을 통해 예측한다. 이를 위해 미국의 FMS에 참여한 국가 데이터를 기반으로 수요국가 확산을 설명할 수 있는 확산계수와 모방계수를 추정하였다. 또한 이 계수들에 대하여 미국과 한국의 정부분야 경쟁력 차이와 종합적인 방산 경쟁력 차이를 적용하여 한국의 상황을 고려한 확산 패턴을 예측하였고, 조기에 확산을 이룰 수 있는 방안을 제시한다. 한국은 국제방산시장에서 모방구매자들에게 상대적인 우위를 점할 수 있을 것으로 보이며, 확산을 조기화하기 위해서는 Medium-High급 무기체계에서의 경쟁력을 High급까지 확장시켜야 하며, 미국의 FMS에서 정부가 주도하지 않는 절충교역 분야인 산업협력을 포함한 대안 제공을 강화하여야 한다.

• Journal of Mechanical Science and Technology
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• 제16권10호
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• pp.1346-1354
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• 2002

The purpose of this work is to study the effects of specularly reflecting wall under the combined radiative and laminar free convective heat transfer in an infinite square duct. An absorbing and emitting gray medium is enclosed by the opaque and diffusely emitting walls. The walls may reflect diffusely or specularly. Boussinesq approximation is used for the buoyancy term. The radiative heat transfer is evaluated using the direct discrete ordinates method. The parameters under considerations are Rayleigh number, conduction to radiation parameter, optical thickness, wall emissivity and reflection mode. The differences caused by the reflection mode on the stream line, and temperature distribution and wall heat fluxes are studied. Some differences are observed for the categories mentioned above if the order of the conduction to radiation parameter is less than order of 10$\^$-3/ fer the range of Rayleigh number studied. The differences at the side wall heat flux distributions are observed as long as the medium is optically thin. As the top wall emissivity decreases, the differences between these two modes are increased. As the optical thickness decreases at the fixed wall emissivity, the differences also increase. The difference of the streamlines or the temperature contours is not as distinct as the side wall heat flux distributions. The specular reflection may alter the fluid motion.

• 대한기계학회논문집B
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• 제27권5호
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• pp.543-552
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• 2003

The effects of a directionally emitting and reflecting dielectric surface on the wall heat flux and medium temperature distribution are studied. The system is an infinite square duct enclosing an absorbing and emitting medium. The emissivity and reflectivity of opaque and gray wall vary with direction. Combined effect of conductive and radiative heat transfer is analyzed using finite difference and the direct discrete-ordinates method. The parameters under study are conduction to radiation parameter, optical depth, refractive index ratio. The results with directional and diffuse properties deviate each other when the conduction to radiation parameter is less than around 0.01. The wall heat flux differs fur optical thickness less than around 0.1. However, the medium temperature profiles differ for optical thickness greater than around 1. Deviations from diffuse property calculations are larger for hot wall with directional property than cold wall with directional property. As n increases from 1.5, the trend changes are observed fur refractive index ratio about n=6.10