• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.211-214
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• 2005

There are emerging many eScience applications. More and more scientists want to collaborate on their investigation with international partners without space limitation by using these applications. Since these applications have to analyze the massive raw data, scientists need to send and receive the data in short time. So today's network related requirement is high speed networking. The key point of network performance is transport protocol. We can use TCP and UDP as transport protocol but we use TCP due to the data reliability. However, TCP was designed under low bandwidth network, therefore, general TCP, for example Reno, cannot utilize the whole bandwidth of high capacity network. There are several TCP variants to solve TCP problems related to high speed networking. They can be classified into two groups: loss based TCP and delay based TCP. In this paper, I will compare two approaches of TCP variants and propose a hybrid approach for high speed networking.

• 한국ITS학회 논문지
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• 제14권6호
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• pp.14-20
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• 2015

국토교통부는 2020년까지 수송부문 온실가스 배출량의 감축목표를 34.3%로 설정하였다. 목표달성을 위해 에코드라이빙 교육 및 정보를 제공하고 있으나 배출량 감축효과가 미비하다. 따라서 본 연구는 연료 효율적인 최적주행전략 모형의 개발을 목적으로 하였다. 종단경사도 및 길이가 다양한 도로지형을 생성하고 주행모드를 바탕으로 하는 시나리오별 속도 프로파일을 Comprehensive Modal Emission Model에 적용하여 연료소모량을 산정하였다. 연료소모량이 최소가 되는 시나리오와 속도변화량을 도출하였다. 도출된 시나리오와 속도변화량을 기반으로 최적주행전략 모형을 개발하였다. 개발된 모형을 검증하고자 실차테스트를 수행하여 일반 운전자의 속도 데이터를 수집하였다. 개발된 모형에 의해 생성된 속도 프로파일과 일반운전에 생성된 속도 프로파일을 분석하고 각각 연료소모량을 산정하였다. 최적주행 시 소모된 연료소모량이 일반운전보다 평균 11.8% 감축하는 것으로 분석되었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.185-189
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• 2003

According to opening Seoul-Busan high speed rail line in 2004, we are studying to offer speedily for the parcel service of high speed rail-combined transport as it does, tender the quality freight services within a one and the same high speed train formation. Therefore, we reviewed for various types of HSR-combined transport and suggested to application methods in Korean high speed rail line. Through these kinds of approaches, we are able to expect the fulfillment of customer needs for high speed rail market segments, the profit maximization of future railway operating companies, and enhancement for cost-effective rail network operation of the mixed traffic on infrastructure cost-reduction in national logistics.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.461-464
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• 2011

Rail transport has been considered as an environmental-friendly transport mode compared with other transport modes such as ship, truck, and aircraft. However, rail industry can not avoid a duty of alleviating Greenhouse gases emission owing to the Korean government polices for green growth which is an economic paradigm that simultaneously pursues growth and environmental improvement. The purpose of this research is to develop a methodology of determining an economic speed of freight train to be green freight train by considering fuel cost, environmental cost, and time cost. In the methodology, we first define a cost function based on cost factors and then suggest an economic speed of freight train by deriving a property.

• 한국ITS학회 논문지
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• 제4권1호
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• pp.97-106
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• 2005

도로상에서 과속과 그로 인한 교통사고를 방지하기 위하여 교통안전시설물 뿐만 아니라 여러 가지의 속도저감 장치 및 교통공학적인 운영기법이 적용되고 있다. 그러나 우리나라에서 속도 저감 및 과속방지를 위하여 무작위 속도단속에 치중하여 온 것이 현실이다. 하지만 최근 ITS기술을 접목하여 속도를 운전자에게 표출시켜 운전자 스스로 자신의 속도를 자각하게 하여 차량의 주행속도를 저감시키는 가변속도표출기가 도입되어 있다. 따라서 본 연구에서는 가변속도 표출기의 개념과 사례를 살펴보고 우리나라의 과천에서 설치된 가변속도표출기의 효과를 운영전과 운영중으로 나누어 가변속도표출기가 차량속도 저감에 미치는 영향 분석해 보았다. 또한 다른 속도 저감장치 즉, 속도제한표지, 스쿨죤 안내표지와의 비교를 통한 유효성을 검증하였다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.149-154
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• 2004

In the semiconductor and the optical industry a new transport system which can replace the conventional sliding system is required. These systems are driven by magnetic field and conveyer belt. The magnetic field damages semiconductor and contact force scratches the optical lens. The ultrasonic wave driven system can solve these problem. In this paper, the relationship of transporting speed according to the change of flexural beam shape and the effect of transporting speed according to the change of weight and amplification voltage are verified. The vibration behavior of flexural beam in the ultrasonic transport system is experimented using Laser Scanning Vibrometer.

• Journal of Mechanical Science and Technology
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• 제14권8호
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• pp.891-899
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• 2000

The flame speed may be decomposed into the burning speed and the flame transport speed. The flame transport speed is affected considerably by the flow direction, variation rate of flow direction, and flow speed in the combustion chamber. Especially, the flow direction and the variation rate of flow direction at the spark plug location during the ignition period have an important effect on the ignition process and the early flame propagation process. We measured the flow direction component and the variation rate of flow direction with a hot wire probe at the spark plug location. It was shown that the representative flow direction of ignition period is the right-vertical direction of crank shaft and it was used to investigate the variation rate of flow direction.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.721-729
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• 2009

Recently, there has been growing necessity to estimate the future travel demand of high speed train because the circumstance of high speed train service is rapidly changing with the launching of 2011 second stage of Gyeongbu high speed railway(Dongdaegu-Busan) and the completion of 2014 first stage of Honam high speed railway(Yongsan-Gwangju), etc. This study was designed to estimate future travel demand by analyzing the transport performance and train service characteristics of Gyeongbu and Honam line. This study presents the maximum load section and the changed future travel demand, which will be applied to establish a train operation plan.

• 한국통신학회논문지
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• 제18권9호
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• pp.1283-1294
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• 1993

큰 대역폭과 낮은 비트 에러율을 가진 고속망환경에서 기존의 낮은 대역폭과 놀은 비트 에러율을 가진 망환경에서 개발된 트랜스포트 프로토콜을 사용할 경우에 비효율적인 구조와 오버헤드로 인하여 성능이게 크게 저하한다. 따라서 고속망환경에 알맞는 새로운 프로토콜로 HSTP(High Speed Transport Protocol)가 제안되었다. 본 연구는 HSTP의 3가지 에러제어 기법과 TP4의 2가지 에러제어 기법을 이용했을 때의 성능과 HSTP의 rate control을 이용하여 흐름제어를 할 경우의 성능을 시뮬레이션 연구를 통하여 평가, 비교하였다.

• Geomechanics and Engineering
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• 제32권5호
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• pp.483-494
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• 2023

High-speed trains became common nowadays due to the need for fast and safe mean to transport goods and people. However, the use of high-speed trains necessitates the examination of the critical speed, which is the train speed at which the maximum settlement of the railway track occurs. The critical speed and railway track settlement have been investigated considering only one train in previous studies. However, it is normal to have two adjacent trains moving at the same time. This paper aims to understand how the interference of two moving trains affects the settlement and critical speed of ballasted railway track. Calibrated three-dimensional finite element models of railway track subjected to one moving train and two moving trains have been developed to address the aim of the study. It is found that the interference dramatically increases the railway track settlement with a percentage increase ranges between 5 and 100%. It is also found that the percentage increase of the railway track settlement depends on the train speed and the distance between the moving trains. In addition, it is found that the thickness of the ballast layer and the stiffness of the subgrade have minor influence on the percentage increase of the settlement. Importantly, the results of this paper illustrate the importance of the interference of the moving trains on the dynamic response of the railway track. Thus, there is a need to consider the dynamic interaction between the adjacent moving trains in the design of railway track foundation.