• 제목, 요약, 키워드: Dropper

검색결과 54건 처리시간 0.046초

DiffServ 네트워크에서 공평성 향상을 위한 TRC Dropper의 성능 분석 (The Performance Analysis of TRC Dropper to improve fairness on DiffServ Networks)

  • 김훈기;홍성화
    • 한국시뮬레이션학회논문지
    • /
    • v.18 no.3
    • /
    • pp.91-102
    • /
    • 2009
  • 평균 윈도우 크기는 평균 처리율과 많은 관계를 가지고 있다. 제안된 dropper는 fairness를 향상시키기 위해 윈도우 크기를 각 플로우의 레벨에 맞게 제어하도록 한다. 경쟁 패킷 드랍은 플로우가 많은 양의 대역폭을 차지하기 위해 동작한다. 경쟁 패킷 드랍 때문에 플로우는 전송 속도를 반으로 줄이게 되며, 이에 따라 코어 링크의 여유 용량이 존재하게 된다. 다른 플로우는 이 새로운 용량을 사용하게 되고, 따라서 다른 플로우는 좋은 처리율을 가지게 된다. 이런 방식으로 TCP의 전송속도를 제어하는 edge router의 새로운 기능 block인 TRC Dropper(Transmission Rate Control Dropper)를 제안한다. 제안한 TRC Dropper를 통하여 플로우들 간에 공평한 대역폭 분배를 실현하여 상대적으로 차별화된 서비스를 제공할 수 있다.

  • PDF

고속선용 드롭퍼 피로분석 연구 (A Study on Fatigue Analysis of Dropper for High Speed Electric Railway)

  • 이태훈;박기범;전용주;류영태;조용현;이기원;박영
    • 한국철도학회:학술대회논문집
    • /
    • /
    • pp.1445-1453
    • /
    • 2009
  • The dropper supports the contact wire and is attached using thimbles and various types of dropper clips on the catenary. Consequently droppers are subject to mechanical loads from friction and buckling during the passage of pantographs. If such mechanical loads occur repeatedly with every passing pantograph, it is possible that the dropper wire will break due to fatigue. In order to investigate failure causes for the high speed line dropper, theoretical analyses and experiments have been carried out. In this paper, mathematical formulas are derived for the prediction of the dropper static load. The measured values in the experiment agree well with the theoretical predictions. And, we performed measurement for the variation of forces on the dropper. To analyze the cause analysis on fracture of dropper wire, we have conducted experiment such as fatigue test of new products, SEM(Scanning Electron Microscope) and EDX(Energy Dispersive X-ray) of fractured specimens in the field. Finally, we also measured the vertical displacements when a pantograph moved at 300km/h under the Korean high speed overhead line.

  • PDF

고속 전차선로 드로퍼에 대한 기계적 하중에 관한 연구 (Mechanical Loads of Dropper for High Speed Electric Railway)

  • 이기천;이태훈;이종우
    • 한국철도학회논문집
    • /
    • v.14 no.3
    • /
    • pp.222-227
    • /
    • 2011
  • 드로퍼는 전차선로에서 여러형태의 클램프로 취부되어 전차선이 수평으로 유지하도록 지지하고, 판토그라프가 통과할 때 굽힘에 대한 기계적 응력에 영향을 받는다. 고속선용 드로퍼의 파단 원인을 조사하기 위해, 이론적 분석 및 시험을 실행하였다. 본 논문에서 사전이도에 의한 드로퍼의 정적 하중을 계산하였고, 시험에서 측정된 값과 유사하였다. 드로퍼 와이어의 파단원인을 분석하기 위해 현장에서 파단된 시료는 SEM 분석을 하였고, 새 시료도 일부 병행하며 시행하였다. 마지막으로, 고속열차가 300km/h로 통과할 때 드로퍼에 대한 동적 하중의 변화를 측정하였다. 기계적 하중이 반복적으로 발생될 때, 드로퍼 와이어는 피로에 의해 파단될 것이다. 이 결과는 고속전차선로 유지보수의 특별 관리와 드로퍼의 수명평가를 하는데 활용될 수 있을 것이다.

전차선로 드롭바 클램프 안전성 확보(I) (Safety Assurance of Dropper Clamp in Overhead Catenary System(I))

  • 이기원;조용현;박영;민병일;권삼영;석창성
    • 한국철도학회:학술대회논문집
    • /
    • /
    • pp.223-226
    • /
    • 2007
  • In the electrical railway, for the improvement of a train speed, it is necessary to study not only the dynamic behaviors of overhead catenary system but the fatigue behaviors of components for a safety assurance according to the increase of vibration level. One of the critical components in the system is a dropper. Therefore, the dynamic force acting on a dropper was measured in the Chungbuk Line and analyzed to figure out the dynamic characteristics the dropper. And in order to assure the safety of dropper clamp and cable, we proposed a test facility as well as test method based on the test results For the further study, we will measure the dynamic forces in the conventional line and high-speed line and make up the test condition, so that the safety of dropper clamps can be assured.

  • PDF

사전이도 적용에 따른 드로퍼에 작용하는 하중 예측 (Prediction of the force on the dropper according to the pre-sag)

  • 이기원;조용현;창상훈;김형철
    • 한국철도학회:학술대회논문집
    • /
    • /
    • pp.972-977
    • /
    • 2009
  • For the improvement of a train speed in the conventional line from overhead system point of view, it is necessary to approach not only in the aspect of the increasement of tension for catenary but the application of a pre-sag. A certain tension acting on a dropper is removed when it is slack by the pantograph passing. Right after the pantograph passes, the dynamic force caused by the mass of contact wire acts on the dropper. If the pre-sag is applied to the catenary, the static force on the dropper is increased. For the assurance of the safety for the dropper, it is necessary to predict the dynamic force. The purpose of this study is to predict and analyze the force on the dropper according to the applied pre-sag.

  • PDF

전차선로 드롭바 길이 계산프로그램 개발 (Development of Calcutation Software for Dropper Length)

  • 이기원;권삼영;김주락;장동욱
    • 한국철도학회:학술대회논문집
    • /
    • /
    • pp.421-426
    • /
    • 2003
  • Dropper which can get to suspend contact wire should be installed with a uniform distribution, so that electric locomotive can have good characteristics of current collection. Because dropper distribution is changed according to a circumstances in the construction field, it is hard to calculate and construct a overhead line. Therefore, in this study, a program was developed to calculate the dropper length in the normal and elevation section. Through the program, it is possible to perform a accurate construction of overhead line and contribute to a improvement of current collection as well.

  • PDF

전차선로 드로퍼 클램프 파단 원인 분석 (The Cause Analysis on Fracture of Dropper Clamp in Catenary System)

  • 김정남;권성태;강계명
    • 한국철도학회:학술대회논문집
    • /
    • /
    • pp.909-914
    • /
    • 2004
  • This study investigate the cause analysis on fracture of dropper clamp in catenary system. Dropper clamp is using as a holder between messenger wire and contact wire in catenary system. To analyze the cause analysis on fracture of dropper clamp, we have conducted experiment such as tension withstand strength test, holding strength test of a new products, SEM and EDX of field fractured specimens.

  • PDF

무효 인상 경간에서 드로퍼 길이 계산 기법 (A dropper length calculation method of the elevating span in overlap area)

  • 권삼영;이기원;조용현
    • 한국철도학회:학술대회논문집
    • /
    • /
    • pp.1503-1510
    • /
    • 2011
  • The dropper length calculation method about the normal same encumbrance spans is well known independent to whether the pre-sag is given or not. But, the dropper length calculation method for the elevating span which consists in the end area of a tensioning section and normally consists with overlaps is not well known. In this study, firstly, we investigate the dropper length calculation method about the elevating span whether the insulator is contained in or not, we also recognize the effect of dropper length due to the change of the take-off point. Secondly, we very this calculation method with a catenary sample data and check again with Gyeongbu HSL design data.

  • PDF

전차선 드로퍼 간격에 따른 집전성능 분석 (Study of Current Collection Performance according to Dropper Spacing for Catenary)

  • 권삼영;이기원;창상훈
    • 한국철도학회:학술대회논문집
    • /
    • /
    • pp.310-317
    • /
    • 1999
  • This paper presents study of collection performance according to dropper spacing for catenary Static characteristics analysis, dynamic simulation, stress and wear analysis for different 5 catenary configurations according to dropper spacing are performed. And collection performance for TGV-Nord catenary system is also analyzed in order to compare and evaluate.

  • PDF

고속철도 전차선로 드로퍼 클램프 내구성 기준 정립에 관한 연구 (A Study on Durability Standard Specification of the Dropper Clamp of Catenary for High Speed Railway)

  • 오완식;양인동;박병곤;홍석진;김성철
    • 전기학회논문지
    • /
    • v.66 no.9
    • /
    • pp.1431-1436
    • /
    • 2017
  • The high-speed railway of catenary system, supplies a stable electric power supply to the train by satisfying the special conditions between pantograph and trolley wire, which operates more than 250km/h mutually sliding and feeding electric lines. According to Korean Railway Standard KRS PW 0026-13 (R), the standard for the grip strength of the dropper clamp in conventional line is established, but the high-speed railway line is not yet. When the grip strength of the dropper clamp is detached from the catenary line of the high-speed railway line, various problems may occur, such as damage to the pantograph due to the collision and arcing. In this paper, it is expected to be used as a basic data for establishing the durability criteria of the high-speed railway dropper clamp by verifying the dropper clamp on the Gyeong-bu and Honam high-speed line.