• Transactions of the Korean Society of Automotive Engineers
• /
• v.13 no.3
• /
• pp.41-47
• /
• 2005

This paper deals with a squeal noise in a brake system. It has been proved that the squeal noise is influenced by the angular misalignment of a disk, disk run-out, with the previously experimental study. In this study, a cause of the noise is examined by using FE analysis program(SAMCEF) and numerical analyses with a derived analytical equation of the disk based on the experimental results. The FE analyses and numerical results show that the squeal noise is due to the disk run-out as the experimental results and the frequency component of the noise equals to that of a disk's bending mode arising from the Hopf bifurcation.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.595-600
• /
• 2004

This paper deals with a cause analysis of a squeal noise in a brake system. It has been proved that the squeal noise is influenced by the angular misalignment of a disk, disk run-out, with the previously experimental study. In this study, a cause of the noise is examined by using FE analysis program(SAMCEF) and numerical analyses with a derived analytical equation of the disk based on the experimental results. The FE analyses and numerical results show that the squeal noise is due to the disk run-out as the experimental results and the frequency component of the noise equals to that of a disk's bending mode arising from the Hopf bifurcation.

• Proceedings of the Korean Information Science Society Conference
• /
• 1998.10c
• /
• pp.390-392
• /
• 1998

기존의 Line Following 알고리즘은 곡선으로 이루어진 영상 패턴을 세선화할 때 두꺼운 분기점을 효과적으로 처리하지 못할 뿐 아니라 폐곡선을 형성하는 부분이 끊어지는 단점이 있어 선분 형태 이외의 일반적인 문자나 이미지 등에 적용하기 어려우므로 Line Following 방식에 근거를 둔 개선된 새로운 세선화 알고리즘을 제안한다. 본 연구에서는 두꺼운 분기점의 문제를 해결하기 위해 선의 모양에 따라 동적으로 변하는 윈도우의 크기를 일정 비율로 조절하고, 폐곡선을 형성한 부분에서는 분기점마다 특정한 tag를 두어 선의 끝을 결정하는 단계에서 tag와 만나는 점에 대해 별도의 처리를 하였다. 이 알고리즘은 기존 알고리즘과 비슷한 처리 속도를 유지하면서도 기존 알고리즘의 단점을 효과적으로 개선하여 곡선이나 복잡한 영상 외에 문자 영상 등에 대해서도 좋은 결과를 보여 주었다.

• The KIPS Transactions:PartB
• /
• v.14B no.6
• /
• pp.413-422
• /
• 2007

This paper addresses a new technique for constructing surface model from a set of wire-frame contours. The most difficult problem of this technique, called contour triangulation, arises when there are many branches on the surface, and causes lots of ambiguities in surface definition process. In this paper, the branching problem is reduced as the surface reconstruction from a set of virtual belts and virtual canyons. To tile the virtual belts, a divide-and-conquer strategy based tiling technique, called the BPA algorithm, is adopted. The virtual canyons are covered naturally by an iterative convex removal algorithm with addition of a center vertex for each branching surface. Compared with most of the previous works reducing the multiple branching problem into a set of tiling problems between contours, our method can handle the problem more easily by transforming it into more simple topology, the virtual belt and the virtual canyon. Furthermore, the proposed method does not involve any set of complicated criteria, and provides a simple and robust algorithm for surface triangulation. The result shows that our method works well even though there are many complicated branches in the object.

• Journal of the Korean Society for Railway
• /
• v.10 no.5
• /
• pp.582-588
• /
• 2007

Since the turnout system in railroad restricts the train speed, the KNR (Korean National Railroad) provides the specification for the speed (130km/h) of the train when the train passes the turnout system. Therefore, the turnout system in pre-existing railroad is necessary to be improved to speed-up for the train. In this study, the dynamic wheel-load field tests have been performed to evaluate the track performance and the roadbed bearing capacity has been examined using numerical analysis at the turnout crossing in the conventional and improved turnout system. The impact factor is estimated using the data sets achieved from the dynamic wheel-load field tests in the conventional and improved turnout system. The stress acting on the roadbed for the improved turnout system is substantially decreased compare to that for the conventional turnout system.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.6 no.2
• /
• pp.107-112
• /
• 2007

A new impedance transforming balun scheme is presented based on the branch-line structure with stubs on the vertical branches. The stubbed vertical branch eliminates the unwanted even mode output and provides only the balanced output of the balun with opposite phase. Also, the use of stubs reduces the branch lengths by two times the stub length, which is useful for the compact balun design.

• KAPE Magazine
• /
• s.124
• /
• pp.6-7
• /
• 2006

한국농촌경제연구원이 11월 25일에 발표한 2007년 1/4분기 축산관측에 따르면 한우육의 경우 전년대비 하락, 젖소는 감소세 유지로 전망했다. 돼지는 산지사육두수 증가로 23~24만원으로 전망, 산란계.육계 모두 사육수는 증가하나 가격은 700~900원 선으로 전망했다. 이에 본지는 축종별 전망의 내용을 요약, 게재한다.

• 해운
• /
• no.10 s.21
• /
• pp.20-24
• /
• 2005

최근 세계해운시장은 조그만 변수에도 급격한 등락을 되풀이하는 등 매우 불안정한 양상을 보이고 있다. 이러한 가운데 금년4/4분기 정기선시황은 약보합세를 보일 것으로 예상되나, 부정기선시황은 상승세를 유지할 것으로 전망됐다. 다음은 한국해양수산개발원이 10월14일 한국선주협회 회의실에서 발표한 2005년도 4/4분기 해운시황전망을 요약하여 정리한 것이다 (편집자 주)

• Journal of the Korean Society for Railway
• /
• v.10 no.6
• /
• pp.735-741
• /
• 2007

A turnout system which permits trains to pass from one track to another is a combination of the switch, the crossing, lead rails which are necessary to connect the switch and the crossing, two guard rails and a switch machine for operating the switch. In Korea, it has been planned to adopt the high speed tilting train which is suitable for the circumstance of Korea and operates at the maximum speed of 180 km/h, at conventional lines by the year of 2010. For the present, the prototype of the tilting train has been fabricated, and has undergoing a trial run. In this study, evaluation of noise around the turnout system induced by the tilting train has been implemented through the field measurements.

• Journal of The Korean Society For Urban Railway
• /
• v.6 no.4
• /
• pp.411-416
• /
• 2018

It is generally not preferable to install a turnout on a sharp curves but it is not desirable for the safety of a train. However, in a mountainous area or a depot where a sufficient space can not be secured to secure a straight line. In this study, in order to analyze the cause of train derailment accident that occurred in the place where turnout is installed in a sharp curves, we performed derailment analysis using line data and accident vehicle data measured at the location where the accident occurred. This derailment coefficient maximum turnout at the start of the track and derailment curve analysis showed that even big enough to cause a derailment as 1.37 in size, which was found to be consistent with the actual site survey results derailment occurred.