• Wind and Structures
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• 제31권1호
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• pp.43-57
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• 2020

Considering the wind barriers induced aerodynamic characteristic variations of both bridge deck and trains, this paper studies the effects of wind barriers on the safety and stability of trains as they run through an urban rail transit cable-stayed bridge which tends to be more vulnerable to wind due to its relatively low stiffness and lightweight. For the bridge equipped with wind barriers of different characteristics, the aerodynamic coefficients of trains and bridge decks are obtained from wind tunnel test firstly. And then, the space vibration equations of the wind-train-bridge system are established using the experimentally obtained aerodynamic coefficients. Through solving the dynamic equations, one can calculate the dynamic responses both the trains and bridge. The results indicate that setting wind barriers can effectively reduce the dynamic responses of both the trains and bridge, even though more wind forces acting on the bridge are caused by wind barriers. In addition, for urban rail transit cable-stayed bridges located in strong wind environment, the wind barriers are recommended to be set with 20% porosity and 2.5 m height according to the calculation results of cases with wind barriers porosity and height varying in two wide ranges, i.e., 10% - 40% and 2.0 m to 4.0 m, respectively.

• 대한토목학회논문집
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• 제2권2호
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• pp.1-10
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• 1982

여객역(旅客驛)이 대개 도심(都心)에 위치(位置)하고 있는 탓으로 도시(都市)의 성장(成長)과 함께 교통혼잡(交通混雜)의 요인(要因)이 되고 있다. 본(本) 연구(硏究)는 부산(釜山)을 예(例)로 하여 여객역(旅客驛)의 입지(立地)에 대한 대안(代案)을 설정(設定)하고 시내통행(市內通行) 및 시외연계(市外連繫) 접근통행별(接近通行別)로 통행발생(通行發生), 통행배분(通行配分), 수단선역(手段選擇), 노선배정(路線配定)의 모의실험(模擬實驗) 과정(過程)을 통하여 여객역(旅客驛)의 입지(立地)가 도시교통체계(都市交通體系)에 미치는 영향(影響)을 비교(比較) 분석(分析)하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권12호
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• pp.5729-5744
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• 2017

Vehicular Ad Hoc Networks (VANET) in the large-scale road section usually have typical characteristics of large number of vehicles and unevenly distribution over geographic spaces. These two inherent characteristics lead to the unsatisfactory performance of VANETs. This poor performance is mainly due to fragile communication link and low dissemination efficiency. We propose a novel routing mechanism to address the issue in the paper, which includes a competition-based routing discovery with priority metrics and a local routing repair strategy. In the routing discovery stage, the algorithm uses adaptive scheme to select a stable route by the priorities of routing metrics, which are the length of each hop, as well as the residual lifetime of each link. Comparisons of different ratios over link length and link stability further show outstanding improvements. In the routing repair process, upstream and downstream nodes also compete for the right to establish repair process and to remain as a member of the active route after repair. Our simulation results confirm the improved performance of the proposed algorithm.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권1호
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• pp.54-60
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• 2012

In this paper, a new permanent-magnet (PM) linear motor is proposed, in which both the magnets and armature windings are placed in the short mover, while the long stator consists of iron core only. Hence, this new PM linear motor can be called a primary permanent-magnet linear motor. It exhibits the advantages of robustness, low cost, high efficiency, high power factor, and high thrust force density. It is especially suitable for long stator applications such as urban rail transit. In this paper, the topology and operation principle of this motor are discussed in detail. The steady-state characteristics including field distributions, flux-linkage, back-EMF, phase inductance and thrust force are investigated. In addition, the technique of skewing stator teeth is adopted to improve the electromagnetic performance. Results from finite element method (FEM) verified the theoretical analysis results.

• 한국자동차공학회논문집
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• 제15권1호
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• pp.38-48
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• 2007

this paper analyses how much acceleration and deceleration of urban rail vehicle should be applied and how to choose an operation mode to minimize energy consumption when train runs between stations within the fixed operation time. The decided operation pattern satisfying the minimum energy consumption becomes a target trajectory and a basis for the controller design criteria. To make this goal it grasps the characteristics of urban rail vehicle, realize operation energy model of urban rail vehicle and verity the accuracy of embodied model the Matlab simulation with the same operation result of real route. It searches for operation pattern to minimize operation energy by changing the acceleration and deceleration on the imaginative route and proposes operation pattern minimizing energy consumption by applying real operation data between stations of Seoul Metropolitan Subway Line 6.

• 대한교통학회:학술대회논문집
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• 대한교통학회 1996년도 제3회 한-중 국제학술회의
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• pp.131-137
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• 1996

This paper discusses the necessity, strategy and objectives of the rail transportation recently developed in Shanghai. The objective should not be regarded just as a term project, but should be taken as an urgent mission with the 21st century, Shanghai should possess a network of about 100km of rail transport lines. To this end, the following measures are suggested : grade separation of all lines on elevated structures ; developing the rail car industries ; full utilization of all available transportation facilities ; optimizing the use of the space resources of highways ; bringing into play the initiatives of all parties concerned. Recently, it has become a popular consensus that the development of high-speed, safe, punctual, comfortable, non-pollution rail transport with large capacity is the best and only solution to Shanghai urban transportation. In this respect, this dissertation deals with the development strategy for current Shanghai rail construction, together with the infractructure in Shanghai, positioning the developing target; meanwhile, some proposals and solutions to hit this target will be put forward for the reference of leaders and experts.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.273-276
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• 2004

Dynamic model of the Korea standardized rubber-tired AGT light rail vehicle, and boundary conditions between vehicle and infrastructures (running track, guidance rail) were defined to analyze vehicular vibration behaviors occurred at the worst condition for straight running track. Using the commercialized software RecurDyn, resultant forces and vibration accelerations of car body and bogies were analyzed. Based on the Korea performance test criteria for urban transit, vertical and lateral vibration of car body were calculated and evaluated as wearing condition of guide wheels. And resultant forces between bogie guidance frame and guide rail in straight running track were analyzed. As the results, the Korea standardized rubber-tired AGT light rail vehicle satisfied the performance criteria and design requirement .

• 한국철도학회논문집
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• 제9권1호
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• pp.95-101
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• 2006

Light rail transit system has many characteristics of better accessibility, frequency service, low construction cost, reduced air pollution and medium-capacity public transport etc. Light rail transit system as a urban transportation system has been growing worldwide since the late 20th century. More than 300 cities around the world have light railway systems. Many medium-size cities in domestic site is planning the construction of light railway. This paper describes the development strategies for the light rail transit industry.

• Tribology and Lubricants
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• 제28권1호
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• pp.19-26
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• 2012

Rolling contact fatigue of an urban railway wheel was analysed during its rolling. A FEM analysis was performed using a 3D modelling of rail and wheel, considering the slope of the rail and nonlinear isotropic and kinematic hardening behavior of the rail and the wheel. The maximum von-Mises stress and contact pressure between the rail and wheel were 656.9 MPa and 1111.4 MPa, respectively, under axial load of 85 kN with friction coefficient of 0. The fatigue initiation life prediction relationships by strain-lifetime (${\varepsilon}$-N) and Smith-Watson-Topper method were drawn for the wheel steel as follows: $N_i=7.35{\times}10^6{\times}SWT^{-3.56}$ and $N_i=5.41{\times}10^{-9}{\times}(\frac{{\Delta}{\varepsilon}}{2})^{-5.77}$. The fatigue lifetimes of the wheel due to rolling contact were determined to be infinite by ${\varepsilon}$-N and SWT methods.

• 시스템엔지니어링학술지
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• 제7권2호
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• pp.13-19
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• 2011

A LRT(Light Rail Transit) is one of the Future Urban Railway Development Project. The project's goal is to reduce a transportation congestion in the center of the city. New transportation is intensely required in order to overcome a limit of the ground transportation that is the existing public transportation, A LRT(Light Rail Transit) construction project to be based on an unmanned driving system is the large composition system that a vehicle, a signal, communication, electric, track etc. were organically integrated as echo-friendly urban transportation systems. It also put a huge budget, which is a large-scale infrastructure projects. It is international trend that Light Rail Transit projects apply a technique in System Engineering for a schedule, cost, quality elevations, and to approach in viewpoints of life-cycle from initial construction steps to operation, abolition. This paper intends to analyze RAM requirements taking into consideration ISO/IEC 15288 throughout life-cycle from concept, design, manufacture, operation and maintenance to the final phase, decommissioning, and the study seeks to suggest directions of efficient use to domestic LRT projects.