• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2000년도 유체기계 연구개발 발표회 논문집
• /
• pp.325-333
• /
• 2000

The aerodynamics of the Wells turbine has been studied using a 3-dimensional, unstructured mesh flow solver for the Reynolds-averaged Navier-Stokes equations. The basic feature of the Wells turbine is that even though the cyclic airflow produces oscillating axial forces on the airfoil blades, the tangential force on the rotor is always in the same direction. Geometry used to define the 3-dimensional numerical grid is based upon that of an experimental test rig. The 3-dimensional Wells turbine model, consisting of approximate 220,000 cells is tested at four axial flow rates. In the calculations the angle of attack has been varied between $10^{\circ}$ and $30^{\circ}$ of blades. Representative results from each case are presented graphically and analyzed. It is concluded that this method holds much promise for future development of Wells turbines.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 춘계학술대회논문집
• /
• pp.1227-1231
• /
• 2001

To provide faster service and to relief the road traffic jam, the increase of service speed of conventional railway has been intensively considered. In this study, we measured and analyzed the vibration ride comfort of Saemaeul Train to evaluate the feasibility of 5km/h speed-up in curves and l0km/h speed-up on straight tracks. Four main lines, such as Honam, Kyungboo, ]anghang, Kyungjeon were chosen as representative lines for speed-up feasibility study. The increase of mean ride comfort index in case of speed-up is 0.5-2㏈. The mean ride comfort index of vertical direction in case of speed-up is 107 ∼110 ㏈ for Honam line, 104 ∼112 ㏈ for Kyungboo line, 108∼112 ㏈ for Janghang line and 105∼108 ㏈ for Kyungjeon line. Through this study, we found that the Saemaul Express has slight margin to increase the service speed from the view point of vibration ride comfort.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2000년도 추계학술대회 논문집
• /
• pp.250-257
• /
• 2000

The speed-up of conventional trains is considered as one of the efficient methods to relieve traffic jam and to increase the capacity of transportation. In this study, we measured and analyzed the ride comfort of a push-pull Saemaeul Train with speed-up of 5km/h in curves and 10km/h on straight tracks as compared with present operation speed of the push-pull Saemaeul Trains. Four main lines-Honam, Kyungboo, Janghang, Kyungjeon- were chosen as representative lines for speed-up feasibility study. The increase of mean ride comfort index in case of speed-up is 0.5-2㏈. The mean ride comfort index of vertical direction in case of speed-up is 107-110㏈ for Honam line, 104-112㏈ for Kyungboo line, 108-112㏈ for Janghang line and 105-108㏈ for Kyungjeon line, which are rather high as compared with German trains of similar grade with maximum vehicle speed of 160km/h.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 추계학술대회논문집A
• /
• pp.475-480
• /
• 2000

The transient dynamic-response analysis of fuel-storage tanks of flying vehicles accelerating in the vertical direction is achieved with finite element method. A fuel-storage tank is a representative example of the fluid-structure interaction problem, in which structure and fluid media interact strongly. For the accurate analysis of this complicated fluid-structure system, we employed ALE(arbitrary Lagrangian-Eulerian) coupling method. Two types of fuel-storage tanks, one with two baffles and the other without baffle, are considered to examine the effect of baffles. The fuel-storage tank with baffles shows more uniform hydrodynamic pressure distribution, resulting effective stress in structural region and faster convergence from transient to steady states. MSC/Dytran, a commercial FEM software for the 3D coupled dynamic analysis, is used for this analysis.

• International Journal of Contents
• /
• 제6권1호
• /
• pp.35-40
• /
• 2010

In recent years, China Digital Media Design related undergraduate education has developed into great dimensions while producing a lot of problems. Now cause of rapid development, Disciplinary Location, Training Objectives and Curriculum require study. Firstly, the paper points out the scope and general process of Digital Media Design through an analysis of properties of digital media industry. Secondly, the paper studies the current status of Digital Media Design-related undergraduate education from the policy of Chinese Ministry of Education and the practice of representative universities. Through questionnaire survey of Digital Media Designers from Beijing, Shanghai and Guangzhou, the paper points out the problems of China Digital Media Design related undergraduate education. Finally, paper brings forward the right direction of new system of China Digital Media Design related undergraduate education.

• 대한안전경영과학회:학술대회논문집
• /
• 대한안전경영과학회 2011년도 추계학술대회
• /
• pp.695-716
• /
• 2011

In the future, smartphone convergences are not only based on the on/offline integration, but also with the integration between mobile communications and broadcasts. Therefore, there is a need to search for new direction of mobile device that enables variety user applications that are different from the existing size and application issue. The aim of this reserch is to improve user interface of smartphone's functional attribute. The survey results in this paper showed that the most preferable attribute of smartphone among the 8 was the wireless internet 25.3%, followed by messaging 20% and application 19.8%, which totaled to 62.5%. But the samples used were mostly limited to those aged 20 through 30. So the results are not considered as a representative preference of all smartphone users, and should be considered otherwise before materializing them to a product. Therefore, for the more liable results the further research should be conducted to gather data from a variety of users of all ages, and the functional attribute should be analysed through QFD.

• 정보보호학회논문지
• /
• 제26권3호
• /
• pp.757-767
• /
• 2016

패스워드 인증은 가장 대표적인 사용자 인증 기법이며 그 중에서 특히 문자 기반 패스워드가 가장 많이 사용되고 있다. 그러나 사용자들이 선택하는 패스워드가 갖는 취약성으로 인하여 사용자로 하여금 강한 패스워드 생성을 유도하기 위해 많은 웹사이트에서는 패스워드 강도를 측정하는 패스워드 미터를 제공하고 있다. 하지만 여기에는 패스워드 미터결과가 일관되지 않고, 정확하지 않은 강도로 피드백하는 문제가 있다. 이에 본 논문에서는 패스워드 미터의 문제점에 대해 알아보며 패스워드 미터의 개선 방향을 제시하고자 한다.

• 대한안전경영과학회지
• /
• 제12권3호
• /
• pp.303-313
• /
• 2010

As more and more the social environment change, the companies try to improve industrial structure. The role of enterprise changed direction from position power to communication power. Social contributed activity - representative of social responsible activities in companies - is means of communication with the community and new marketing strategy. The most important element of successful social contributed activity is member's volunteering minds. Volunteer mind based on practical behavioral philosophy. This is right people for company. In this paper, we discussed company social responsibility and suggested standard guide line for voluntary record reflection when the company hire new employees.

• Bulletin of the Korean Chemical Society
• /
• 제34권2호
• /
• pp.510-514
• /
• 2013

The structural change of Nafion polymer electrolyte membrane (PEM) induced by hot-pressing, which is one of the representative procedures for preparing membrane-electrode-assembly for low temperature fuel cells, was investigated by $^2H$ nuclear magnetic resonance (NMR) spectroscopy. The hydrophilic channels were asymmetrically flattened and more aligned in the membrane plane than along the hot-pressing direction. The average O-$^2H$ director of $^2H_2O$ in polymer electrolyte membrane was employed to extract the structural information from the $^2H$ NMR peak splitting data. The dependence of $^2H$ NMR data on water contents was systematically analyzed for the first time. The approach presented here can be used to understand the chemicals' behavior in nano-spaces, especially those reshaping and functioning interactively with the chemicals in the wet and/or mixed state.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2010년도 학술발표회
• /
• pp.1179-1183
• /
• 2010

본 연구에서는 하천유역에 대한 호우의 대표 이동방향을 결정하였다. 대상유역으로는 내성천 유역을 고려하였으며, 101개의 호우사상을 선정하여 각각의 호우사상별로 방향적 특성을 분석하였다. von Mises 분포의 주방향을 이용하여 모든 호우사상의 대표 이동방향을 결정하고, 이를 이용하여 내성천 유역에 대한 호우 대표 이동방향을 결정하였다. 아울러 호우 발생특성별(장마, 태풍, 대류성 강우)로 호우의 방향적 특성을 분류하여 각각의 특성이 구분될 수 있도록 하였다. 적용 결과, 태풍에 의한 호우의 이동방향은 기존 연구결과와 유사하게 주로 북동 방향으로 진행되었으며, 장마와 대류성 강우에 의한 호우가 대표방향 결정에 가장 큰 영향력을 갖는 것으로 나타났다. 아울러 대상유역에 대한 호우의 대표 이동방향은 mode의 특성이 뚜렷하게 한 방향으로 나타나며, 내성천 유역의 경우 대표 호우 이동방향은 59.45도로 결정되었다. 이러한 결과는 한반도에 발생하는 강우의 특성과도 잘 부합하는 것으로 판단된다.