• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1900-1906
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• 2008

According as zone of life of big city is expanded by new city development etc.., need special skill master plan compensation which can be systematic for wide area traffic problem solution and confusion expense minimization in the metropolitan area because wide area of capital region traffic is gone continuously and continues. Accordingly, Kyonggi Province suggested rapid-transit railway achievement that can connect Seoul Gangnam in 20 minutes with Dongtan new city recently. MLTM(Ministry of Land Transport and Maritime Affaris) announced "Capital region railway network improvement plan research services (2007.12)" result that Gangnam High-speed railway route (Suse $\sim$ Dongtan $\sim$ Pyeongtaek) construction for offer High-speed railway service to capital region and Kyonggi southern part area inhabitantses and need to line capacity tribe solution by Seoul-Busan high-speed railway second-stage and Honam high speed railroad completion. Is judged that need examination about wide area rapid-transit railway combined application operation that take advantage of rail track reserve capacity of High-speed railway for utilization efficiency elevation of country and efficient investment of national finance according as High-speed railway and Gangnam rapid-transit railway route that is suggested in Kyonggi Province are overlaped. Therefore, in this research, I wish to quote investment efficiency plan of railroad business by that different kind's train is run in uniformity track by presenting combined application operation plan and working expenses curtailment effect etc. that is optimized through analysis of roadbed and E & M technology condition, intermediate station plan, train operation planning etc. in case of wide area rapid-transit railway and high-speed railway run combined application.

• Journal of Auto-vehicle Safety Association
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• v.10 no.2
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• pp.6-12
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• 2018

Optimized section shape of aluminum bumper backbeam for enhancing the front high speed crashworthiness was investigated. Front body analysis model of a convertible vehicle was built up and parameter studies were carried out with changing the inner rib shape and the section thickness distribution. First an inner rib shape displaying most efficient structural performance was selected. Next, for the selected section the effect of section thickness combination was examined. Also, a light weighed backbeam section displaying crash performance over the current design was suggested. Finally RCAR front low speed impact analyses were carried out for the optimized models.

• Structural Engineering and Mechanics
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• v.13 no.5
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• pp.505-532
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• 2002

In this study, the analysis of high-speed vehicle-bridge interactions by a simplified 3-dimensional finite element model is performed. Since railroads are constructed mostly as double tracks, there exists eccentricity between the vehicle axle and the neutral axis of cross section of a railway bridge. Therefore, for the more efficient and accurate vehicle-bridge interaction analysis, the analysis model should include the eccentricity of axle loads and the effect of torsional forces acting on the bridge. The investigation into the influences of eccentricity of the vehicle axle loads and vehicle speed on vehicle-bridge interactions are carried out for two cases. In the first case, only one train moves on its track and in the other case, two trains move respectively on their tracks in the opposite direction. From the analysis results of an existing bridge, the efficiency and capability of the simplified 3-dimensional model for practical application can be also verified.

• The KSFM Journal of Fluid Machinery
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• v.7 no.5 s.26
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• pp.43-49
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• 2004

A turbo blower, driven by a high-speed blushless DC motor, was designed as a efficient substitute of a ring blower or a roots blower. Computational analysis and performance tests have been performed to investigate performance characteristics of the blower. Experimental measurements showed that the blower has a good stability margin. This paper gives an outline of design, computational flow analysis and performance test for aerodynamic evaluation of the variable speed turboblower.

• Journal of the Korean Physical Society
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• v.73 no.12
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• pp.1889-1894
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• 2018

An innovative small-scale piezoelectric energy harvester has been proposed to gather wind energy. A conventional horizontal-axis wind power generation has a low generating efficiency at low wind speed. To overcome this weakness, we designed a piezoelectric windmill optimized at low-speed wind. A piezoelectric device having high energy conversion efficiency is used in a small windmill. The maximum output power of the windmill was about 3.14 mW when wind speed was 1.94 m/s. Finally, the output power and the efficiency of the system were compared with a conventional wind power system. This work will be beneficial for the piezoelectric energy harvesting technology to be applied to the real world such as wireless sensor networks (WSN).

• Journal of the Korean Society for Railway
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• v.11 no.2
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• pp.145-150
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• 2008

The objective of this research is to design the roller rig for the maintenances of high-speed train bogies operated on the tracks. Roller rigs have been studied and researched to develop the faster, safer and more efficient railway system. It is to reduce the time of testing vehicles and to make as wide a range of tests available as possible. Therefore, it is very important issue to check and evaluate the dynamic responses of high-speed train after several years of operation. This paper presents a study on the conceptual design and dynamic model to develop the roller rig for the routine maintenances of high-speed trains bogies with maximum speed of 350km/h. ANSYS was used to analyze the wheel/roller's contact behavior of driving axle and ADAMS was used to verify and analyze the dynamic behaviors of roller rig.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.1
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• pp.37-46
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• 2003

The transient responses on arbitrarily interconnected digital transmission lines are analyzed by an efficient node discretization technique. Since the proposed node discretization technique offers an efficient means to discretize transmission lines, the transient waveform at any position on the arbitrarily interconnected lines is easily predicted. Dispersive microstrip multiconductor transmission lines arbitrarily connected are analized for generality. The derivation of frequency-dependent equivalent circuit elements of coupled transmission lines have been carried out by the spectral domain approach(SDA). The effects of variations of excited pulse width on the crosstalks of the high-speed microstrip coupled-lines are also investigated. It has been well known that the crosstalk spike level is monotonously increased when the coupling length and effective permittivity of substrate are increased. In this paper, it is found that the variations of crosstalk level are not further monotonous as shortening the exciting pulse width toward several picosecond. The results are verified by the generalized S-parameter technique.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.3
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• pp.55-64
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• 2004

In this paper, we propose an efficient FFT algorithm for high speed multimedia communication systems, and present its pipeline implementation results. Since the proposed algorithm is based on the radix-4 butterfly unit, the processing rate can be twice as fast as that based on the radix-2$^3$ algorithm. Also, its implementation is more area-efficient than the implementation from conventional radix-4 algorithm due to reduced number of nontrivial multipliers like using the radix-23 algorithm. In order to compare the proposed algorithm with the conventional radix-4 algorithm, the 64-point MDC pipelined FFT processor based on the proposed algorithm was implemented. After the logic synthesis using 0.6${\mu}{\textrm}{m}$ technology, the logic gate count for the processor with the proposed algorithm is only about 70% of that for the processor with the conventional radix-4 algorithm. Since the proposed algorithm can be achieve higher processing rate and better efficiency than the conventional algorithm, it is very suitable for the high speed multimedia communication systems such as WLAN, DAB, DVB, and ADSL/VDSL systems.

• Journal of Information Processing Systems
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• v.7 no.3
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• pp.531-542
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• 2011

In this paper, we propose a new congestion control scheme for high-speed networks. The basic idea of our proposed scheme is to adopt a game theory called, "Minority Game" (MG), to realize a selective reduction of the transmission speed of senders. More concretely, upon detecting any congestion, the scheme starts a game among all senders who are participating in the communication. The losers of the game reduce the transmission speed by a multiplicative factor. MG is a game that has recently attracted considerable attention, and it is known to have a remarkable property so that the number of winners converges to a half the number of players in spite of the selfish behavior of the players to increase its own profit. By using this property of MG, we can realize a fair reduction of the transmission speed, which is more efficient than the previous schemes in which all senders uniformly reduce their transmission speed. The effect of the proposed scheme is evaluated by simulation. The result of simulations indicates that the proposed scheme certainly realizes a selective reduction of the transmission speed. It is sufficiently fair compared to other simple randomized schemes and is sufficiently efficient compared to other conventional schemes.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.3
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• pp.284-291
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• 2006

Recently with the motorizing of electric home appliances and car systems, there is increasing interest in high efficiency electric motors. Thus, the present study described the operating characteristics of coreless AFPM motor that is highly efficient in high speed driving, and discussed its electric characteristics from the perspective of design. In particular, we examined back electromotive force and the magnetic field characteristic in slits, which have significant effects on the characteristic of the motor, and conducted simulation and experiment on control characteristic according to inductance characteristic. This study analyzed torque speed and efficient operation characteristic as well as control characteristic through comparing the result of motor design with the result of output characteristic experiment based on the electric network method. Furthermore, we evaluated vibration and noise that may occur due to the absence of core.