• 제목/요약/키워드: Urban-Transit

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A Study on Velocity-Brake Force Resulted from Deceleration Signal (감속도 신호에 의한 속도-제동력 고찰)

  • Lee, U-Dong
    • Proceedings of the KIEE Conference
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    • 2003.11c
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    • pp.616-620
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    • 2003
  • Brake action is important in train operation. In case of diesel motor cas, coachs and wagon, the brake system is only act on the stop of train, but it is emphasis on safety and convenience in urban transit system such as EMU, subwar, AGT, etc. Brake of EMU has two types. one is called service brake that is used at normal operation. The other is called emergency brake. it is used at emergency operation. Service brake bring a EMU to a halt through a blending brake that form electronic brake and frictional brake. Generally EMU compose motor car and trailer car. Blending brake bring a EMU to a halt through a blending brake that form electronic brake of motor car and frictional brake of trailer car. Blending braking technology have different characteristics each nations or manufacturing companies. but deceleration command that is parameter decide blending brake. According to deceleration command, electronic brake and frictional brake are applied differently So braking power is different. electronic brake and frictional brake must be used appropriately as deceleration command. Also braking facilities must be stopped EMU more economically and safely through revision of algorism about blending brake according to output diagram. Thus The purpose of paper is to propose blending braking control way as consideration of braking output diagram used deceleration command that influence blending brake of EMU.

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A Study on the Insulation Properties for Stator Form-wound Winding by Thermal Degradation Test (가속 열열화 시험에 의한 고정자 형권 코일의 절연특성에 관한 연구)

  • 채승훈;김상걸;오현석;신철기;왕종배;김기준;이준웅
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.115-118
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    • 2000
  • In case of developing new motor, many examinations was tested to decide a motor efficiency and reliability. To give reliability judgment, traction motor winding insulation was tested by electrical method after appling electrical, heat, mechanical, environmental stress. In this study, stator form-wound winding of traction motor in urban transit E.M.U was tested by accelerative thermal degradation test. Stator form-wound winding was tested on the accelerative degradation composed of heat, vibration, moisture, overvoltage and researched insulation resistance, dielectric loss, partial discharge for insulation degradation properties, evaluated withstand voltage. Degradation temperature was $230[^\circ{C}]$, $250[^\circ{C}]$, $270[^\circ{C}]$, for stator form-wound winding respectively. On the test results of accelerative thermal degradation, insulation properties were relied all temperature until 10 times and expected life was evaluated by the rule of reducing $10[^\circ{C}]$ life into halves. Expected life was 31.8 years. It is guaranteed insulation reliability because of exceeding 25 years life times as considering.

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Theoretical analysis of simply supported channel girder bridges

  • Hu, Hong-Song;Nie, Jian-Guo;Wang, Yu-Hang
    • Structural Engineering and Mechanics
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    • v.56 no.2
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    • pp.241-256
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    • 2015
  • Channel girder bridges that consist of a deck slab and two side beams are good choices for railway bridges and urban rail transit bridges when the vertical clearance beneath the bridge is restricted. In this study, the behavior of simply supported channel girder bridges was theoretical studied based on the theory of elasticity. The accuracy of the theoretical solutions was verified by the finite element analysis. The global bending of the channel girder and the local bending of the deck slab are two contributors to the deformations and stresses of the channel girder. Because of the shear lag effect, the maximum deflection due to the global bending could be amplified by 1.0 to 1.2 times, and the effective width of the deck slab for determining the global bending stresses can be as small as 0.7 of the actual width depending on the width-to-span ratio of the channel girder. The maximum deflection and transversal stress due to the local bending are obtained at the girder ends. For the channel girders with open section side beams, the side beam twist has a negligible effect on the deflections and stresses of the channel girder. Simplified equations were also developed for calculating the maximum deformations and stresses.

Analysis of the Economic Feasibility of a Monorail on Mt. Bomun on Daejeon (신교통수단 모노레일의 관광지 도입에 대한 경제적 타당성 분석 -보문산 일대를 중심으로-)

  • Kim, Myungsoo
    • Journal of the Korean Society for Railway
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    • v.16 no.3
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    • pp.226-232
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    • 2013
  • Recently, CO2 reduction policies are being promoted as parts of ESSD(Environmentally Sound and Sustainable Development), and many local governments are interested in monorails as a new means of transport. Here we report on a feasibility study for introducing a monorail system by considering the travel demands in the Mt. Bomun area in Daejeon, based on the area's population. The feasibility of a monorail system on Mt.Bomun varies with respect to the demographic scale, mode shares, and operational distances. The strategies introduced here will help identify any tourist spots where local governments are trying to introduce monorail systems as a new system of transit.

Experimental and numerical investigation of track-bridge interaction for a long-span bridge

  • Zhang, Ji;Wu, Dingjun;Li, Qi;Zhang, Yu
    • Structural Engineering and Mechanics
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    • v.70 no.6
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    • pp.723-735
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    • 2019
  • Track-bridge interaction (TBI) problem often arises from the adoption of modern continuously welded rails. Rail expansion devices (REDs) are generally required to release the intensive interaction between long-span bridges and tracks. In their necessity evaluations, the key techniques are the numerical models and methods for obtaining TBI responses. This paper thus aims to propose a preferable model and the associated procedure for TBI analysis to facilitate the designs of long-span bridges as well as the track structures. A novel friction-spring model was first developed to represent the longitudinal resistance features of fasteners with or without vertical wheel loadings, based on resistance experiments for three types of rail fasteners. This model was then utilized in the loading-history-based TBI analysis for an urban rail transit dwarf tower cable-stayed bridge installed with a RED at the middle. The finite element model of the long-span bridge for TBI analysis was established and updated by the bridge's measured natural frequencies. The additional rail stresses calculated from the TBI model under train loadings were compared with the measured ones. Overall agreements were observed between the measured and the computed results, showing that the proposed TBI model and analysis procedure can be used in further study.

Numerical Analysis of Discharge Flow in Type III Hydrogen Tank with Different Gas Models (Type III 수소 저장 용기에서 가스 모델(gas model)에 따른 배출(discharge) 현상의 수치 해석적 연구)

  • KIM, MOO-SUN;RYU, JOON-HYOUNG;JUNG, SU YEON;LEE, SEONG WOO;CHOI, SUNG WOONG
    • Journal of Hydrogen and New Energy
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    • v.31 no.6
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    • pp.558-563
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    • 2020
  • Hydrogen is attracting attention as an alternative energy source as an eco-friendly fuel without emitting environmental pollutants. In order to use hydrogen as an energy source, technologies such as hydrogen production and storage must be used, and new storage methods are being studied. In this study, the behavior of hydrogen in the storage tank were numerically studied under high-pressure hydrogen discharge conditions in a Type III hydrogen tank. Numerical results were compared with the experimental value and the results were quantitatively analyzed to verify the numerical implementation. With the results of pressure and temperature values under a given discharge condition, the Redich-Kwong gas model showed the adequate models with the smallest error between numerical and experimental results.

A Study on the Effect of Travel Time and Cost by Means on the Mode and Destination Choice of a Commuter by the Household Income Class - Based on the Utility-Based Accessibility Approach - (통행수단별 소요시간과 비용이 가구소득계층별 통근통행자의 수단 및 목적지 선택에 미치는 영향 분석 - 효용기반 접근도 개념에 근거하여 -)

  • Jang, Seongman
    • Journal of Korea Planning Association
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    • v.54 no.1
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    • pp.52-66
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    • 2019
  • Travel is a factor that stimulates the vitality of the urban and is widely used as an indicator of sustainable growth of the region. In Korea, however, no studies has been made to predict changes in traffic and calculate the accessibility of the region by comprehensively considering the socio-economic conditions of the travelers. The purpose of this study is to classify commuters according to the household income and to analyse the traffic characteristics of each class. The analysis results are aggregated into two. First, the analysis of study found different transport characteristics for different income classes. This is the result that underpins the argument of a previous study that suggested that a discriminatory approach is necessary for each income in determining the accessibility of the region. Second, this study calculated utility values differently for each income class based on the transit time and cost required between each zone. Through these measures, transport characteristics were analyzed by income class using indicators that considered transportation infrastructure, and socio-economic conditions of the travelers. This study is meaningful in that it provided the basis for calculating the accessibility that could take into account the activities of the housing consumers in establishing domestic housing policies.

An Analysis of the Effectiveness of Social Path Using the Space Syntax Technique (Space syntax 기법을 활용한 Social Path 효과분석)

  • Choi, Sung Taek;Lee, Hyang Sook;Choo, Sang Ho;Jang, Jin Young;Kim, Su Jae
    • Journal of Korean Society of Transportation
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    • v.33 no.2
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    • pp.192-203
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    • 2015
  • Pedestrians not only walk along pedestrian pathways, but also choose unusual routes such as passing through buildings or crossing large scale open spaces. This study defines these unusual paths as social path, and includes them into one of the pedestrian road categories. Previous pedestrian accessibility and route choice studies could not evaluate correctly the space connectivity or optimal route because the social path was not considered properly. Therefore, this study analyzes the effectiveness of the social path in view of space connectivity focused on Coex and Seoul stations in Seoul, which are representative transit oriented development(TOD) areas. Global integration, which is widely used in network analysis, is selected (as performance index) to identify the space hierarchy and define new pedestrian links. The study results show that the network connectivity is improved especially in the main streets and social paths. This study demonstrated that the social path should be considered in finding the pedestrian optimal route from the practical perspective.

Classification of Multi-modal Transfer Center Considering the Regional and Functional Characteristics (지역 및 기능적 특성을 고려한 복합환승시설 유형분류)

  • Kim, Tae-Gyun;Lee, Sam-Su;Byun, Wan-Hee
    • Land and Housing Review
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    • v.4 no.1
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    • pp.89-98
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    • 2013
  • In recent years, it was recognized that aurban policy paradigm of sustainable urban growth management and transportation policies have been shifted : from the era of automobile-oriented policy to the era of public transport policy. Against this backdrop, the introduction of the multi-modal transfer center is very consequential. Therefore, it is necessary for the introduction of wide-area and local-centric transfer facilities, as well as the center of the country-led national backbone transfer center. This study was applicable at the multi-modal transfer center plans to introduce guidelines to provide transit facilities, considering the regional and functional characteristics to classify the types of multi-modal transfer center. The final types of multi-modal transfer center were classified into six, and by considering the combination of the criteria to be classified. The multi-modal transfer center type classification based on the case analysis of the types of facilities at domestic and abroad. If the data of multi-modal transfer are accumulated continuously, can expect a more reliable type classification.

Identifying Key Factors to Affect Taxi Travel Considering Spatial Dependence: A Case Study for Seoul (공간 상관성을 고려한 서울시 택시통행의 영향요인 분석)

  • Lee, Hyangsook;Kim, Ji yoon;Choo, Sangho;Jang, Jin young;Choi, Sung taek
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.18 no.5
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    • pp.64-78
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    • 2019
  • This paper explores key factors affecting taxi travel using global positioning system(GPS) data in Seoul, Korea, considering spatial dependence. We first analyzed the travel characteristics of taxis such as average travel time, average travel distance, and spatial distribution of taxi trips according to the time of the day and the day of the week. As a result, it is found that the most taxi trips were generated during the morning peak time (8 a.m. to 9 a.m.) and after the midnight (until 1 a.m.) on weekdays. The average travel distance and travel time for taxi trips were 5.9 km and 13 minutes, respectively. This implies that taxis are mainly used for short-distance travel and as an alternative to public transit after midnight in a large city. In addition, we identified that taxi trips were spatially correlated at the traffic analysis zone(TAZ) level through the Moran's I test. Thus, spatial regression models (spatial-lagged and spatial-error models) for taxi trips were developed, accounting for socio-demographics (such as the number of households, the number of elderly people, female ratio to the total population, and the number of vehicles), transportation services (such as the number of subway stations and bus stops), and land-use characteristics (such as population density, employment density, and residential areas) as explanatory variables. The model results indicate that these variables are significantly associated with taxi trips.