• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.9-11
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• 2008

When a squirrel cage induction motor is loaded, the electromagnetic noise can increase depending on the load current. It is due to the air gap harmonic fluxes from the rotor current induced during loading. This unfavorable noise can be anticipated by calculating the radial force waves in the air gap, vibration mode shapes of them, and stator core natural frequencies of each mode. With the experimental tests with the different rotor slot numbers, the variation of electromagnetic noise is studied between on-loaded and loaded running.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.170-176
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• 2003

The pantograph for Korean High Speed Train was developed and had been evaluating by through "G7- R＆D for home grown high speed train technology". In this study, a relation in mechanical aspect between the train running speed and the current collecting performance of the pantograph is conducted.'for this study, a measuring system for current collecting performance and mechanical characteristics is developed and installed on the prototype Korean High Speed Train, and measurement is conducted while the train runs on the test track. The measuring system is composed of video monitoring system and telemetry & data processing unit. It monitors whether the hazard behavior in the pantograph is occurs or not, and measures acceleration and vertical contact force between the pan head and catenary. Through this study, evaluation of a mechanical vibration characteristics and trend of the pantograph and a interface performance of pantograph - catenary up to 200㎞/h train speed are facilitated.

• 전기의세계
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• v.17 no.4
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• pp.7-12
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• 1968

In recent years the development of the SCR has made possible the control of the power system. It is one example that the speed control of the induction motor can be done by changing the frequency with the S.C.R. This paper is devoted primarily to a study of the running characteristics of the single phase induction motor through the experimental and theoretical methods when the speed of the motor is controlled by varying the conduction period in current with S.C.R. under the constant frequency. We conclude from the experiments that the adjustment of the phase angle in current is equivalent to the change of the supply voltage to the motor. Therefore, the speed control of the motor such as a fan duty motor is possibly by this methods.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.200-205
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• 2004

The pantograph for Korean High Speed Train was developed and had been evaluating by through 'G7-R&D project for home grown high speed train technology' In this study, in mechanical aspect, the variation trend of contact force between pantograph and catenary according to the train running speed and driving pattern is conducted. A measuring system for current collecting performance and mechanical characteristics is used for this study, developed and installed on the prototype Korean High Speed Train, and physical characteristics were measured while the KHST runs on the test track. Through this study, remarkable trends of variation are found and analyzed from measured acceleration and vertical contact force between the pan head in pantograph and contact wire in catenary system according to the driving pattern and the train raised a running speed up to 300km/h.

• International Journal of Railway
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• v.2 no.4
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• pp.187-192
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• 2009

Running test of the Korean High-Speed Train using remote controlled measuring system have been executed on the high speed track in order to evaluate and verify the performance of the train. In this paper, influencing factors on the contact force which represents dynamic characteristics between the pantograph and contact wire are analyzed, according to the track condition, span type and running condition. By the analytical study on the test data, we figured out that contact force and dynamic characteristics of the pantograph are mainly affected by running behavior of the train and the span distance which the train passes.

• Journal of the Korean Society for Railway
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• v.8 no.4
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• pp.342-347
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• 2005

The Korean High-Speed Train(HSR 350x) had been developed by through 'G7-R&D project' in 1996-2002, and has been testing and evaluating it's reliability on the high-speed line until now. A number of core equipments designed and developed by using domestic technologies were boarded on the HSR 350x. In order to verify the performance of HSR 350x and core equipments such as traction system, brake system and pantograph, sophisticated testing and evaluating procedures should be considered and applied. In this paper, the tested and analysed results about the dynamic characteristics of HSR 350x pantograph are introduced in a view point of the mean contact force and it's variation trend, criterion of current collection, and up-lifting of contact wire when the MSR 350x running up to 350 km/h. Through the test and evaluation, we verified that HSR 350x pantograph had an excellent current collection performance and good dynamic characteristics as it had been designed.

• Journal of the Korean Society for Railway
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• v.10 no.2 s.39
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• pp.112-116
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• 2007

In this paper, we proposed a selection and application recommendations of ZnO arresters for DC electric traction vehicles. To decide the Continuous Operating Voltage($U_C$), the Rated Voltage($U_r$), and the Nominal Discharge Current(In), we measured and analyzed system voltages and surge currents flowing the arrester installed on a DC electric traction vehicle under running state. System voltages measured up to 1,800 V in 1,500 V-system, and surge currents were recorded up to 3 times per a running-service-route and their magnitudes were ranges of $150A{\sim}2kA$. From these results and a standard EN50163, we could proposed $U_C$, $U_r$, and In available for the 1,500 VDC electric traction vehicles.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.5
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• pp.108-126
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• 2023

In this paper, the dynamic hard shoulder running for bus only (HSRFBO) was presented to solve the traffic congestion by increase the capacity in chronic congested sections of highways, and a simulation was performed to evaluate the comparison with the current hard shoulder running for all vehicles(HSRFAV) and median bus only lane and HSR(MBOLHSR). According to the evaluation results, it was evaluated to be more advantageous in terms of traffic flow and safety than the current HSRFAV. In addition, the speed of passing buses is slightly reduced compared to the MBOHSR, but the speed of entering and exiting buses is increased and the speed of buses and cars is greatly improved. Therefore It was analyzed that the efficiency of transport personnel was also improved. In particular, it is expected that traffic flow will be stabilized as the difference in speed between passenger cars and buses will be greatly reduced, and violations of exclusive bus lanes by passenger cars will be greatly reduced. In addition, the operation time of HSR is greatly reduced, so that the original function of the shoulder lane can be maintained as much as possible. As a result, it was analyzed that the risk of accidents was significantly reduced when operating HSRFBO compared to when operating MBOHSR, and cross-conflicts with high accident severity did not occur.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.902-908
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• 2006

We propose a scheme for more efficient navigation in a hierarchical file system. In the proposed scheme, a program running in the background computes the degree of relationship between a current file and others, and builds a list of the most related files. The current relationship metric being used by the program is a linear combination of five parameters: the name, the directory path, the type, the created time, and the last accessed time of a file. A simulated annealing algorithm is used in order to determine the weighting factors of the parameters. A set of experiments were conducted in order to access the effectiveness of the proposed scheme.

• Journal of Magnetics
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• v.17 no.2
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• pp.73-77
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• 2012

We investigate spin transfer torque (STT) in magnetic multilayer structures using micromagnetic simulations. We implement the STT contribution for magnetic multilayer structures in addition to the Landau-Lifshitz-Gilbert (LLG) micromagnetic simulators. In addition to the Sloncewski STT term, the zero, first, and second order field-like terms are also considered as well as the effects of the Oersted field due to the running current are addressed. We determine the switching current densities of the free layer with the exchange biased synthetic ferrimagnetic reference layers for various cases.