• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.3
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• pp.300-305
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• 2013

The torque was calculated with inductance and iron loss. Because the linkage flux can change the inductance, and q-axis current can change the iron loss. Therefore, precise estimation of torque can achieve with the inductance and iron loss detail calculations. So, in this paper, the d, q-axis inductance was verified through CVCT(Current Vector Control Test) and DCT(Direct Current Test). Also in the iron loss calculation, the prediction of all areas of current magnitude, phase angle and speed was very difficult. And LUT(Look-Up Table) was spent time and resource largely. Therefore, iron loss mathematization was proposed according to current magnitude, phase angle and speed. Also, characteristics of IPMSM were comprised of analyzed and experimental values.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.372-379
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• 2008

In the case of pantograph, three models of HSR350X(G7), KTX-I and KTX-II have been already introduced into the field of domestic high speed train. This thesis intends to explain performance test result of the conditionally purchasing pantograph that is progressing up to now. The pantograph is being developed to localize pantograph that was applied to KTX-I. Also, it consider criteria that applied for verification of design contents and method of dynamic test that verify pantograph's current collecting performance.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.132-139
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• 2011

ATP(Automatic Train Protection) system in railroad signalling system is on-board signalling system which is controlled by train control information such as location and speed of trains. Safety is ensured by transmitting the train control information between on-board and wayside device in the ATP system. When an engineer disregards the speed limit on a tachometer, the train is automatically stopped by the on-board device. Recently, the studies of increasing speed of the train have been developed. Eurobalise in ERTMS/ETCS system is used in case that speed of trains is up to 500[km/h]. A study of safety braking distance is needed by increasing the speed of train in the ATP system. Train data and track data are required to calculate the safety braking distance. The train data includes formations of trains, length of trains, service brake and emergency brake etc. Also, the track data includes slope of track, curve of track, length of track, speed limit etc. In this paper, the speed profile is computed by analyzing the train and track data in the ATP system. It is demonstrated by applying to subway line 2 in Seoulmetro through the on-site test.

• Journal of Information Processing Systems
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• v.16 no.5
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• pp.1064-1073
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• 2020

The general situation of system composition and safety management of high-speed railway terminal is investigated and a comprehensive evaluation index system of operational security is established on the basis of railway laws and regulations and previous research results to evaluate the operational security management of the high-speed railway terminal objectively and scientifically. Index weight is determined by introducing interval eigenvalue method (IEM), which aims to reduce the dependence of judgment matrix on consistency test and improve judgment accuracy. Operational security status of a high-speed railway terminal in northwest China is analyzed using the traditional model of fuzzy comprehensive evaluation, and a general technique idea and references for the operational security evaluation of the high-speed railway terminal are provided. IEM is introduced to determine the weight of each index, overcomes shortcomings of traditional analytic hierarchy process (AHP) method, and improves the accuracy and scientificity of the comprehensive evaluation. Risk factors, such as terrorist attacks, bad weather, and building fires, are intentionally avoided in the selection of evaluation indicators due to the complexity of risk factors in the operation of high-speed railway passenger stations and limitation of the length of the paper. However, such risk factors should be considered in the follow-up studies.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.514-520
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• 2001

A 300Wh class flywheel energy storage system using high Tc superconductor bearings(HTC SFES) is being developed by KIMM and KEPRI. HTC SFES consists of a flywheel rotor, superconductor bearings, a motor/generator and its controller, touch-down bearings, vacuum chamber, etc. Stiffness and damping values of superconductor bearings were experimentally estimated to be 67,700N/m and 29Ns/m respectively. The present HTC SFES was designed to have maximum operating speed of 33000 rpm, which is far above 2 rigid body mode critical speeds of 645rpm and 1,275rpm. Leaf-spring type touch-down bearing were utilized to have the system pass safely through the system critical speeds. It has been experimentally verified that the system can run stably up to 28,000 rpm so that HTC SFES is now expected to reach up to its maximum design speed of 33,000rpm without any difficulties. The Halbach array motor & generator has also been proven its effectiveness on transferring electrical energy to a rotaing composite flywheel in kinetic form.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.4
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• pp.357-364
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• 2011

In this study, ring-shaped acoustic resonators were proposed to be installed in a silencer to increase the acoustic performance of silencer in the low-frequency range. Evaluation of noise reduction performance of acoustic resonator arrays was carried out by measuring the random-incidence absorption coefficient. It was found that the absorption coefficient of resonator array was measured up to 1 at 125 Hz of 1/3-octave band center frequency. Insertion losses of silencers with ring-shaped acoustic resonator arrays were measured based on ISO 7235. The results were shown that the ring-shaped resonator could increase the insertion loss up to 13 dB without flow, whereas 7 dB when flow speed reached 15 m/s. As increasing the flow speed above 15 m/s, the effect of acoustic resonator decreased due to the effect of nonlinear air damping of the resonator. It was also found that the increment of pressure drop by the presence of resonator arrays was about 9 % at flow speed of 25 m/s.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.3
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• pp.492-497
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• 2015

An overhead rigid conductor system is mainly applied to the subway and recently studies on the rigid system have been conducted for applications such as tunnels of high-speed line and speed improvement of a conventional lines up to 250km/h. Power feeding performance which is the most important in a rigid system can be measured by contact force and characteristics of this contact force are related to the shape and material of the R-BAR. In this paper, we analyze the measurements of contact force, current heating temperature, impedance of a rigid conductor which was developed in Korea, after that we compare static characteristics of home and abroad rigid conductors which have various shapes and materials.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.39-46
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• 2023

In this study, the dynamic behavior of friction bearings of PSC (Pre-Stressed Concrete) box train continuous bridge was numerically analyzed at 10 km/h intervals up to 600 km/h according to the increasing speed of the next-generation high-speed train. A frame model was generated targeting the 40-meter single-span and two-span continuous PSC box bridges in the Gyeongbu High-Speed Railway section. The interaction forces including the inertial mass vehicle model with 38 degrees of freedom and the irregularities of the bridge and track were considered. It was calculated the longitudinal displacement, cumulative sliding distance and displacement speed of the bridge bearings at each running speed so that compared with the dynamic behavior trend analysis of the bridge. In addition, long-term friction test standards were applied to evaluate the durability of friction plates.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.12
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• pp.39-47
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• 2005

An acoustic emission technique is applied to the tensile tests of the plastic specimen under the different test speeds and the structural integrity evaluation of the plastic shell structure. Several AE characteristics are acquired from the tensile tests and they are proven to be useful parameters in evaluating its structural integrity. The results shows that tensile strength has almost constant value over some higher speed region while revealing some increasing tendency in strength as the test speeds up in lower speed region. The crack initiation loads and locations are accurately evaluated during the static compression testing of the plastic shell structures by using acoustic emission technique.

• Journal of Biosystems Engineering
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• v.32 no.6
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• pp.395-402
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• 2007

This study was carried out as basic researches to develop the leaf vegetable harvester. This study was conducted to investigate physical and rheological properties of bundled leaf vegetables with stem (Chinese leek, Crown daisy and Chamnamul) as test materials held and picked-up by a machine. Stress-strain behavior, stress relaxation, and strain recovery for the bundled materials were analyzed using simple Maxwell model. Physical and rheological properties of the materials were investigated by measuring rupture load, deformation and stress experimentally. Also, strain recovery time when unloading was measured using super high speed camera. Recorded recovery time for stress-strain behavior was0.026 s for Chinese leek with liner strain recovery, 0.046 s for Crown daisy and 0.05 s for Chamnamul with non-linear strain recovery. Furthermore, the strain recovery time for permanent deformation was 0.026 s, 0.046 s, and 0.05 s for Chinese Leek, Crown daisy and Chamnamul, respectively. Finally, strain recovery time and strain recovery ratio for the test materials were 0.17 s, 60.4% in Chinese leek, 0.12 s, 55.3% in Crown daisy, 0.15 s, 58.7% in Chamnamul. Here strain recovery time means that how fast the test materials are recovered from initial deformation and strain recovery ratio means how much the test materials are recovered from initial deformation. The above results show that the test materials can be held enough and moved by the belts.