• The Journal of Information Technology
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• v.4 no.3
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• pp.155-163
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• 2001

In this paper, we implemented sigmoid active function which make it difficult to design of the digital neuron networks. Therefore, we designed of the high speed processing of the sigmoid function in order to digital neural networks. we designed of the MAC(Multiplier and Accumulator) operation unit used residue number system without carry propagation for the high speed operation. we designed of MAC operation unit and sigmoid processing unit are proved that it could run of the high speed. On the simulation, the faster than 4.6ns on the each order, we expected that it adapted to the implementation of the high speed digital neural network.

• International Journal of Contents
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• v.7 no.3
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• pp.19-28
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• 2011

This paper presents a fast and practical motion synthesis algorithm for massive number of quadruped animals. The algorithm constructs so called speed maps that contain a set of same style motions but different speed from a single cyclic motion by using IK(Inverse Kinematics) solver. Then, those speed maps are connected each other to form a motion graph. At run time, given a point trajectory that obtained from user specification or simulators, the algorithm retrieves proper speed motions from the graph, and modifies and stitches them together to create a long seamless motion in real time. Since our algorithm mainly targets on the massive quadruped animal motions, the motion graph create wide variety of different size of characters for each trajectory and automatically adjusted synthesized motions without causing artifact such as foot skating. The performance of algorithm is verified through several experiments

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.278-282
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• 2007

The riding comfort and the durability of train are effected by the rail irregularities such as track gauge, superelevation, alignment, longitudinal level, twist, cant and cross level. Inspection and estimation of irregularities are very important to maintain the rail condition. Generally, the EM120 has been utilized to measure the rail irregularities once a month in Korea. However, the EM120 can be operated at night time only, because the inspection speed of EM120 is much slower than the speed of high-speed trains. Also, the EM120 is too slow to inspect effectively for the whole commercial line. Therefore, we have mounted the track inspection system on the High-Speed Rolling Stock 350 eXperimental (HSR350X) and measured the rail irregularities to confirm the condition of a rail while running 300km/h. In this paper, the track inspection system mounted on HSR350X is mainly considered, and the measured results through test run are introduced.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.3
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• pp.63-73
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• 1993

In this paper, fuzzy control algorithm for the speed ratio control of the electro-hydraulic rig type continuously variable transmission(CVT) was proposed and the CVT performance tests were carried out for the optimal operation of the engine simulator. The experimental results for the constant throttle and the acceleration modes showed that the engine can be run on the optimum operating line, representing the power and economy mode, by the fuzzy control of the CVT speed ratio. Comparing the PID control with the fuzzy control, it was found that the fuzzy control showed better performance with the faster rising time and smaller steady state error. The result of this study can be used as basic design materials for developing the transmission control unit of the CVT.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.372-374
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• 2001

An automatic operation of train is executed by an automatic train operation(ATO) system. The main function of ATO system is to control train speed as well as train brake system. So that train can stop at its programed position on platform and run with passenger comfort. In this paper, the gain scheduled control is designed for speed control considering the disturbances. The simulation is executed to verify the speed control performance and to compare its performance with the conventional PI and general Fuzzy control.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.275-280
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• 2003

The Korean high speed train is designed to run at very high speed such as 350km/h. At this time, ballast in roadbed is dispersed by high speed air flow and this hits the substructure of the train. It becomes the factor of damaging the train. To investigate the main factor and possibility of ballast dispersion, the substructure flow is measured by Kiel-Probe Array System at G7 train experiment. And the wind tunnel experiment is performed with ballast in our research. Also CFD analysis is performed by assuming that the flow field is 2D and using simple shaped cross-tie and flat substructure of the train. By comparing the experimental results and CFD analysis, the accuracy of the analysis is checked. They will become the basic research data for the analysis and optimization of train substructure to prevent the ballast dispersion.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.399-403
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• 2002

The transmission system of high speed train serve in the severe condition compared with those of other trains, namely, they have to transmit high power to run with high speed and they have to make maximum use of the limited space. To clarify the strength of gear for Korea High-Speed Train, a bending fatigue test of gear specimen is performed and compare with actual gear's. From this result, specimen test is useful to infer S-N curve and endurance limit of actual gear that much time and expense are consumed.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1270-1275
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• 2006

Korean Train Express (KTX) has opened to commercial traffic since 2004 at maximum speed 300km/h, and Korea High-speed Railway (HSR-350x) was developed by Korean government, several institutes, and related companies. HSR-350x is now being investigated its performance and tested at the high speed line. In 2004 December, HSR-350x was run over 350km/h and proved its running performance. In vehicle system, the faster the vehicle runs, the more vibration increases. To improve the riding comfort of high-speed trains, it needs to devise the vibration absorber. In this paper, we propose the installation of the semi-active damper to the power car of HSR 350x and present the specification and the damping characteristics.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.268-273
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• 2006

The ride comfort is more important in the train speedup. Generally, it is defined as the vehicle vibration. There are many studies on evaluation method of ride comfort for railway. But the ride comfort for Korean high speed train(HSR 350x) has been assessed by statistical method according to UIC 513R. It is very difficult for HSR 350x to run at constant speeds above 310 km/h during 5 minutes required in UIC 513R because of the same operational condition as KTX and the infrastructures. In this paper, the ride index at high speed above 310 km/h has been predicted by using those obtained below 310 km/h and the comfort for HSR 350x has been reviewed in these speeds.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.8
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• pp.139-145
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• 1996

Tapping is one of the most widely used machining operations. There are several methodes of producing external screw threads, e.g. turning, milling with single or multiple cutter, rolling, and grinding, but the methods available for cutting enternal threads are less numerous, and for threads in small holes, tapping is employed almost exclusively. In this study, the tap with the various geometry has been developed in order to tap special workmaterial at considerably higher cutting speed than that of the conventional HSS tap. The experimental tests are run with various cutting speed by using a piezo type tool dynamometer to measure tapping torque. Tapping torque is affected by the design of the tap, which seems to be due to internal friction and shearing of the metal. It is clarified that the process of chip formation strongly depends on rake angle, relief angle, angle of twist.