• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.417-419
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• 2016

Internet of things(IoT) services should be available to provide unattended operation in a remote area, long battery life, low-cost infrastructure, two-way communication platform. Urban transit in Busan is made up of the wire-based infrastructure except for voice infrastructure of transmit/receive and new data infrastructure is required for Internet of things(IoT) services. Urban transit environments in Busan were analyzed in order to apply LoRa Wireless Network(the standard communication way of IoT) and proposes a building after a Disaster Evacuation System.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.1
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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.

• Journal of the Korea Society of Computer and Information
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• v.10 no.3 s.35
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• pp.209-217
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• 2005

In this paper, we propose hierarchical inter-domain load balanced QoS routing in a large scale of network. And a scheme of calculating resources' costs for precomputation schemes in hierarchical routing is proposed. and a scheme for selecting a path among multiple precomputed paths is proposed. We also propose a QoS routing scheme for transit and intra traffic in a large scale of domain-based network. For a domain in the network, the routing scheme first precomputes K multiple paths between all pairs of ingress and egress border routers while considering balancing of the expected load then selects paths with the probability of path selection. The routing scheme combines inter and intra domain routings seamlessly and uses the same cost calculation scheme.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.310-315
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• 2006

In several years, the geographic information system has been being applied into various departments, i.e. estate, transportation, prevention against disasters, agriculture, environment, etc. Especially, it is very useful for us to manage the infrastructures of urban transit which are scattered and located in the vast areas of city. But, in the 2D geographic information system, it is impossible to manage the various inner facilities of stations which are in the same spatial location on GIS. Then, the 3D station management system has been developed for the efficient management of station facilities in urban transit. Through this system, from the virtual cyberspace of station on PC, we can move and go to any places of station we want without going to the station fields. So, we can manage the various information of location information, basis information, maintenance information about the inner facilities such as architectural structures, machinery facilities, electronic equipments. And, this system is also connected with the drawings and technical documents in each facilities. So, we're sure, this system will improve the efficiency of maintenance work and information management of stations.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1380-1386
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• 2012

It is important to consider supply voltage stability in case of design and construction of a substation at electric railway because a urban transit is operated by electricity and it is driven simultaneous in the same section. This paper study on variation of the dynamic characteristic of supply voltage according to the track environment and spatial distribution as driving of urban transits. Simulation tool, TOM(Train Operations Model) software is used to ensure stability of feeder system being used around the world. As results of simulation, voltage of the contact wire is in limits on driving operation diagram of urban transits. Also, it has confirmed that there is a correlation the phase current, depending on the speed of urban transit and track environment like vertical gradients and curve radius.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.501-504
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• 2001

We used time-of-flight method to analyse transport properties of charge carrier which is produced by X-ray exposure. It is the research of charge transport and specific property of trap that is performed in direct digital x-ray image receptor. But the results shows us different measurement value of electron and charge drift mobility and it is difficult to precise analysis about charge transport properties and trap mechanism. We measured transit time and drift mobility of charge carriers using time-of-fight method to evaluate the correlation of a-Se thickness change and electric field. We made a testing glass with a-Se of 470 ${\mu}{\textrm}{m}$ thickness on corning glass using thermoevaporation method and built Au electrode with 300nm, 2$\phi$ on both sides of a-Se. As a result of this experiment, electron and hole transit time was each 229.17 $\mu$s and 8.737 $\mu$s at 10V/${\mu}{\textrm}{m}$ electric field and Drift mobility was each 0.00174 $\textrm{cm}^2$/V.s, 0.04584 $\textrm{cm}^2$/V.s.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.2
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• pp.196-200
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• 2013

In this paper, the design of PRT vehicle power supply system is discussed. Since there is no power feeding line facilities in PRT system under development, the PRT vehicle must have its own energy storage device on board. For the energy storage device, ultra-capacitor bank is applied due to its fast charging capability and long life time. Charging the Ultra-capacitor bank is performed by wireless inductive power transfer system. The capacitor bank is charged up in less than 10 seconds when the vehicle is traveling by passenger stations. In this paper the design of the ultra-capacitor bank and the wireless inductive power transfer system for the PRT vehicle are discussed. Tests are conducted for the both system and the result shows the efficiency of the wireless inductive power transfer system is higher than 80%.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.5
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• pp.65-70
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• 2015

Lightning is one of hazards affecting the rapid-transit railway system. There are two effects, which are direct lightning surge to electric car line and induced lightning surge. Protection methods for the direct lightning surge are studied with various occasions, however, study of induced lightning surge is insufficient in spite of a large or small effects. In this paper, it is analysed the way that serge voltage is induced to electric car line by lightning strikes. By modeling the propagation process and the coupling phenomenon of electromagnetic wave produced by lightning strikes, it is achieved to make integrative circuit model combined with existing electric car model. The study is conducted into three different waveform of electromagnetic wave produced by lightning; rectangular wave, double exponential distribution wave, triangle wave. It is also simulated that the inducing serge is coupled to electric car line in an arbitrary location. The simulation results in that, when rapidly changing rectangular wave is supplied, maximum power is induced to electric car line.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.1 s.232
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• pp.124-131
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• 2005

BOM(Bill of Materials) is a list or description of raw materials, parts and assemblies that define a product. Although it is very important for maintenance information system of urban transit, it has problems that the size of database, inaccuracy and the flexibility which is measured as the number of updating records in accordance with added new product or engineering change. To solve these, we divide BOM to a master BOM and various function BOM constructed from the master BOM. That is the component based BOM management system, which is mutually independent and integrated efficiently using component technology. Consequently, after defining the component based master BOM, it is easy to manage the data structure, even restruct, in case there is a need for change of environment or data.

• Journal of Urban Science
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• v.7 no.2
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• pp.1-9
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• 2018

In this study, Analysis of DRT model and contribustion based on the case of local governments adopting the Demand Responsive Transit(DRT) in order to provide transportation in public transportation service weak area. Based on the case of Yeoju Area, the contribution of the DRT was analyzed. The DRT model was established as a fixed and call type model with taxi and bus transportation. Based on the results of the happy taxi service in Yeoju Area in 2016, the contribution of DRT was analyzed. According to the happy taxi performance of Yeoju city, it was introduced to 27 villages, and operated 4,188 times. And 9,111 people used it and Yeoju Area supported about 53 million Won. The contribution of local governments was analyzed in terms of local government, users, and social aspects. On local government aspects, we analyzed the budget cuts and complaints resolution. On the user aspects, we analyzed waiting time reduction, walking time reduction, travel time reduction, comfort, punctuality, and stability. On social aspects, we analyzed taxi and regional economy activation, and convenience of mobility.