• Journal of the Korean Society for Railway
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• v.6 no.3
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• pp.149-155
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• 2003

The development of railway vehicles involves the proper selection of design parameters not only to achieve high speed but also to reduce the vibration of the train. In this study an analytical model of a freight car is developed to find the critical speed. The freight car can generate the snake motion of the lateral and yawing motion of the car body, the bogie, and the wheelset. Numerical analysis for the nonlinear equation motions with 17 degrees of freedom showed the running stability and critical speed due to the snake motion. Also, the vibration modes of the freight car was calculated using ADAMS/RAIL, which showed that the critical speed have the yawing modes of the car body and the bogie. Finally this paper shows that the snake motion of the vehicle can be controlled with the modifications of the design parameters.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.202-212
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• 2010

하천복원설계 절차에 따라 현상태의 유역통합관리 대안 적용 전후에 대한 수리학적 특성을 저수량과 평수량에 대해 HEC-RAS 모형과 RMA2 모형을 이용하여 분석하였으며, 기본적인 수리모형의 계산결과를 바탕으로 목감천 하천설계 구간 4.5 km에 대해 하천의 수리 수문학적 분석을 수행하였다. 그리고 목감천에서의 지배유량을 산정하여 Rosgen의 하천분류법에 의해 하천형태를 분류한 후 경험식에 의한 하천복원설계를 수행하였다. 즉, 하천형태의 분류에 따라 하도 평면형 결정 및 하상경사 예측, 경험식에 의한 하도 단면 및 하상경사의 결정, 사행파장에 의한 여울의 위치를 각각 결정하였다. 목감천 하천복원 설계를 위한 구체적인 상세설계안을 마련하기 위하여 하천복원설계에 필요한 하도 평면형, 하도 종단형, 하도 단면형을 결정하였으며, 상세 설계의 기초자료로 활용한다.

• Journal of the Korean Institute of Rural Architecture
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• v.22 no.4
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• pp.17-25
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• 2020

This preliminary study examines historical background of construction, establishment process, and destroy process for the Goryeo-sa-haeng-guan in Myeong-Ju during the Song Dynasty. The research was conducted based on local journals at that time. The Myeong-Ju is one of the famous port cities for marine trade. The Myeong-Ju had a good relationship with the Goryeo. Especially, the Song Dynasty built the Goryo-sa-haeng-guan for Goryeo envoys and traders to maintained a good partnership with Goryeo. A comprehensive review on records and historical issues of the Goryeo-sa-haeng-guan helps us to understand foreign policy and inter-relationship between Korean and China.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.286-286
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• 2003

• Proceedings of the Korea Water Resources Association Conference
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• 1984.07a
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• pp.57-66
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• 1984

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6B
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• pp.373-378
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• 2012

In this study, a new empirical equation for the transverse dispersion coefficient has been developed based on the theoretical background in river bends. The nonlinear least-square method was applied to determine regression coefficients of the equation. The estimated dispersion coefficients derived by the new equation were compared with observed transverse dispersion coefficients acquired from natural rivers and coefficients calculated by the other existing empirical equations. From a comparison of the existing transverse dispersion equations and the new proposed equation, it appears that the behavior of the existing formula in a relative sense is very much dependent on the friction factor and the river geometry. However, the new proposed equation does not vary widely according to variation of friction factor. Also, it was revealed that the equation proposed in this study becomes an asymptotic curve as the curvature effect increases.

• Journal of Wetlands Research
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• v.10 no.2
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• pp.67-79
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• 2008

The one-dimensional (1D) finite-difference method (FDM) with Abbott-Ionescu scheme and the two-dimensional (2D) finite-volume method (FVM) with an approximate Riemann solver (Osher scheme) for unsteady flow calculation in river are described. The two models have been applied to several problems including flow in a straight channel, flow in a slightly meandering channel and a flow in a meandering channel. The uniform rectangular channel was employed for the purpose of comparing results. A comparison is made between the results of computation on 1D and 2D flows including straight channel, slightly meandering channel and meandering channel application. The implementation of the finite-volume method allows complex boundary geometry represented. Agreement between FVM and FDM results regarding the discharge and stage is considered very satisfactory in straight channel application. It was concluded that a 1D analysis is sufficient if the channel is prismatic and remains straight. For curved (meandering) channels, a 2D or 3D model must be used in order to model the flow accurately.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.415-420
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• 2009

공학 분야에 있어서 수치 해석적 연구가 많은 주목을 받고 있다. 경제적 측면을 비롯한 다양한 측면에 있어서 모의의 간편성으로 인해 하천에서의 수리학적 거동모의에 수치해석 모의 분석법이 쓰이고 있는데 모의결과의 비교 및 검증을 위해서는 현장 실험 혹은 모형실험이 선행되어야만 한다. 본 연구에서는 강재로 제작된 S자 형태의 만곡부를 두 개 갖고 있는 사행수로 실험 장치를 제작하여 두 가지 유량조건 (30, 60 ${\ell}$/sec.)과 두 가지 하류단 수위조건 (30, 40 cm)에 대하여 수평 2차원 유속분포 자료를 이용하였다. 유속장의 자료는 Sontek사에의 3차원 micro-ADV(Acoustic Doppler Velocimeter)를 이용하여 측정하였다. 주 흐름은 직선구간에서는 중앙에서 최대 유속을 나타내며, 좌우대칭적인 유속분포의 모습을 보이고, 만곡부에서는 수로안쪽을 따라 최대유속이 발생하였다. 이는 만곡부의 정점부분에서의 이차류 발생 및 소멸에 의한 연직방향 유속분포를 통해 발생되는 현상이라 사료된다. 또한 본 연구에서는 2차원 하천해석 상용프로그램인 RAMS (베타버젼)와 SMS를 이용하여 흐름해석을 수행하였다. 실험 자료와의 비교를 통하여 두 가지 상용프로그램의 경우 모두 다소 과대 산정되는 것을 알 수 있었고, 만곡부와 직선부의 유속분포에 대한 모의결과는 RAMS (RAM2)의 결과가 보다 실험결과와 잘 일치하는 것으로 분석되었다. 위와 같은 유속분포의 분석을 통하여 각각의 상용소프트웨어의 적용성을 비교해 보았으며 향후 오염물질 거동해석 모형을 실험수로에 적용하여 그 결과를 비교할 수 있을 것으로 예상한다.

• Journal of Korean Library and Information Science Society
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• v.36 no.3
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• pp.213-231
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• 2005

Yeonhaengrok is a document recorded by one member of the envoy sent to the China from 17 to 19 century. Ik-mo Lee, a member of the envoy, wrote a full explanation of the visit from Nov. 24 1796 to Mar. 7 1797 in his writing $\ulcorner$Byongjin Yeonhaengrok${\lrcorner}$. $\ulcorner$Byongjin Yeonhaengrok${\lrcorner}$, which is omitted in the complete collection of $\ulcorner$Yeonhaengrok${\lrcorner}$, has been newly found at the Family of Suwon Baek's house locating at the Sanggum Vil., Yongsan Town, Jangheung County of Chonnam Province. $\ulcorner$Byongjin Yeonhaengrok${\lrcorner}$ contains an historical meaning that it is an official record of the official envoy that was sent first after the Injong's enthronement in China. This study observed the bibliographical features of $\ulcorner$Byongjin Yeonhaengrok${\lrcorner}$, the time of the transcription, the progress of receiving by the Suwon Baek family. And certified the details of the Byongjin envoy, going and returning between Hanyang and Beijing, staying schedules of the envoy in Beijing.

• Journal of Korea Game Society
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• v.7 no.2
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• pp.61-72
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• 2007

Prohibition Clauses of Business of Money Changing(${\S}32(1)7$) on the Game Industry Promotion Act of 2007 was introduced for the purpose of preventing game from becoming gambling. By making the independent requisite of constituting a crime that there was no criminal punishment former times, it is possible actively to deal with mixing of game and gambling. Prohibition Clauses of Business of Money Changing prevent the material or formless results that are obtained on the use of game from making a business of money change, intermediation of money change, or re-purchase of it. The material or formless results mean points, prizes, game moneys, or game data that is obtained on the abnormal use of a game. Most real money trade of a game item will be pull into the application of Prohibition Clauses of Business of Money Changing on the interpretation of it. Therefore this clauses have a tremendous effect upon the business of sweated workshops and intermediation web sites of game items. None the less Prohibition Clauses of Business of Money Changing will have positive influence to the future of game industry through the separation of game and gambling.