• The KSFM Journal of Fluid Machinery
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• v.13 no.6
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• pp.77-82
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• 2010

This study has conducted numerical analysis for lubrication system of transmission for commercial vehicle. The lubrication oil system in transmission can be applied to a large scale commercial vehicle which is over 15tons. The flow rate of lubricating oil has been obtained for each of branch port from the lubrication pipe. The results from numerical simulation are mainly suggested for the mass flow rate of lubrication oil in the rotating main shaft of transmission system. It has been found that the mass flow rate from oil hole increased with an rotating rate of main shaft. The flow characteristic from oil hole has been presented for the lubricating system in the manual transmission.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.409-414
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• 2011

The drivers of commercial vehicle easily feel tired because of a long time driving and bad road condition. Therefore it is very important to make the driver seat comfortable. This paper introduces the suspension system of driver's seat using magnetic force. The combination of linear spring and magnetic force can make nonlinear spring which has optimal stiffness for minimal vibration transmissibility. The vibrations of driver's seat floor are measured in various road condition. And the numerical simulations and experiments are performed to define the optimal parameter of magnetic suspension system.

• Journal of Auto-vehicle Safety Association
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• v.12 no.2
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• pp.21-26
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• 2020

This paper presents an anti-lock braking system for commercial vehicles with pneumatic brake system by using slip ratio. By virtue of system reliability, most commercial vehicles adopt pneumatic brake system. However, pneumatic brake systems control is more difficult than hydraulic systems due to a longer time delay and the system nonlinearity. One of the major factors in generating braking forces is the wheel slip ratio. Accordingly, the proposed ABS strategy employs the slip ratio threshold-based valve on/off control. This threshold-based algorithm is simple but effective to control the pneumatic brake systems. The control performance of the proposed algorithm has been validated via simulation studies using MATLAB/Simulink and Trucksim. The results show ABS by using slip ratio reduces the braking distance and improves vehicle control.

• Journal of the Korea Society of Computer and Information
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• v.14 no.6
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• pp.41-49
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• 2009

In this paper, the multi-camera calibration algorithm for optical motion capture system is proposed. This algorithm performs 1st camera calibration using DLT(Direct linear transformation} method and 3-axis calibration frame with 7 optical markers. And 2nd calibration is performed by waving with a wand of known length(so called wand dance} throughout desired calibration volume. In the 1st camera calibration, it is obtained not only camera parameter but also radial lens distortion parameters. These parameters are used initial solution for optimization in the 2nd camera calibration. In the 2nd camera calibration, the optimization is performed. The objective function is to minimize the difference of distance between real markers and reconstructed markers. For verification of the proposed algorithm, re-projection errors are calculated and the distance among markers in the 3-axis frame and in the wand calculated. And then it compares the proposed algorithm with commercial motion capture system. In the 3D reconstruction error of 3-axis frame, average error presents 1.7042mm(commercial system) and 0.8765mm(proposed algorithm). Average error reduces to 51.4 percent in commercial system. In the distance between markers in the wand, the average error shows 1.8897mm in the commercial system and 2.0183mm in the proposed algorithm.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.1-2
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• 2015

본 논문에서는 ANC 시스템의 빠른 수렴을 위하여 2차 경로 필터를 초기화하는 방법을 제안한다. 대부분의 ANC 시스템에서는 2차 경로 필터를 설계하기 위하여 LMS 알고리즘을 사용한다. 그러나 기존의 방법들은 2차 경로 필터의 초기 계수 값을 0으로 설정하기 때문에 필터의 수렴 시간이 길어진다. 이를 해결하기 위하여 본 논문에서는 미리 구한 계수 값을 2차 경로 필터의 초기값으로 설정하여 필터의 수렴 시간을 줄이는 방법을 제안한다. 제안한 방법을 사용하면 2차 경로 필터의 초기 단계부터 에러가 작게 나타내며, 이에 따라 ANC 시스템의 수렴이 빨라진다. 상용 헤드셋을 이용하여 제안하는 방법을 실험하였으며, 기존 방법보다 빠르게 ANC 시스템이 수렴하는 것을 확인하였다.

• The Magazine of the IEIE
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• v.33 no.8 s.267
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• pp.23-31
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• 2006

본 고에서는 IPv4/IPv6 연동 환경에서 고려해야 할 차세대 보안 기술들에 대해 기술한다. IPv6는 국내외로 2008년부터 본격적으로 도입되기 시작하여 2010년에는 상용망 구축이 활발해 질 것으로 예상되며, 기존 IPv4와의 연동에 대한 요구는 2020년까지는 지속적으로 유지될 것으로 보인다. 이때 반드시 연구가 선행되어야 할 것 중의 하나는 보안 문제로 현재 표준화 관점과 망 운영 관점에서 분석하고 이를 해결하기 위한 연구가 진행중이다. 본 고에서는 이를 IPv6 프로토콜 보안 문제와 IPv4/IPv6 연동 보안 문제로 나누어 분석하고, 실제 방화벽 등에서 이러한 보안 문제를 해결하기 위한 방법 등을 기술한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7A
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• pp.741-747
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• 2004

This paper will discuss the Design and Implementation of common Backplane for TDM/Data System. Transmission performance of over 10Gbps in proposed commom or converged backplane architecture was discussed and demonstrated using readily available components.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05a
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• pp.117-124
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• 1996

원전의 상용 부하추종운전 능력을 위한 노심 제어기법인 Mode K를 개발하고, 이를 차세대원전의 제1주기 주기초에 적용하여 일일 부하추종운전을 수행할 때의 노심 거동을 ONED94 전산코드로 모사 계산하였다. 계산 결과, 단순하면서도 유연한 형태의 붕산 농도 변화를 수용하면서 제어봉으로 출력분포 및 반응도를 동시에 제어하는 Mode K 제어 논리가 잘 작동하였으며, PbXb운전에 비하여 액체 폐기물 생성량이 30%까지 감소하였다.

• Proceedings of the Korean Society for Information Management Conference
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• 2011.08a
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• pp.53-58
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• 2011

빠르게 진화하는 상용 웹 사이트들의 검색 및 인터페이스 기술과 달리 도서관의 OPAC 시스템은 그 변화를 빨리 수용하지 못해 그 결과로 OPAC 사용에 있어 이용자들은 불편을 느끼고 있다. 이처럼 도서관 OPAC의 진보적인 개발이 시급한 실정에서 등장한 개념이 '차세대 OPAC'이다. 본 연구는 차세대 OPAC의 특성을 열거하여 핵심 항목으로 구성 된 체크리스트를 개발하고 향후 이를 이용하여 대학도서관에서의 차세대 OPAC 적용 현황을 평가 분석하는 도구로 사용하고자 하였다. 본 논문에서는 최종적인 연구의 초기단계로 차세대 OPAC에 관한 선행연구 분석을 통해 체크리스트 예비 항목을 작성하는 것으로 제한한다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.566-573
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• 2017

The chine of high speed vessels does not only play a role in changing position when planing but also helps balancing the hull. It also has a great influence on resistance performance. However, designing a chine requires a lot of experience because it is influenced by various factors such as displacement, transom shape, draft and width. Such a design is not based on an empirical formula, but the purpose of this study is to provide basic guidelines regarding the shape of chine through calculation. This design was developed using Yacht-one, a commercial design program, and analysis was performed using Star-CCM+, also a commercial analysis program. Analysis of the hull selected in this study was carried out by Dynamic Fluid Body Interaction (DFBI) method. Analysis of the chine was carried out at chine angles of 15, 16, 17, and 19degrees, at a speed of 30knots. The result indicated that the highest trim occurred at 16 degrees among the four chine angles considered, and the highest heave occurred at 15degree. In terms of resistance performance, minimum resistance was observed at 16 degrees. Consequently, for minimum ship resistance, it is necessary to complete calculations in accordance with the chine angles, ${\pm}2$ degrees from the initial chine angle, which should be carried out a the design stage.