• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.4
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• pp.107-117
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• 1996

The shift feeling, a driver experiences during gear shifting, is a major factor in manual transmission quality. Recently, the shift feeling has becoming more severe every year in proportion to the higher torque and revolution speed of today's automotive engine. In this paper, first, the diagram of a relation between cone angle, sleeve chamfer angle, and friction coefficient of ring is investigated for easy design of Synchromesh system. And then, methodology to solve the shift problems such as clashing noise and rough shift, ect. by analyzing the synchronization procedure in sequence and by investigating the shift waveform if presented.

• 한국가시화정보학회:학술대회논문집
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• 2004.12a
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• pp.33-40
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• 2004

A 4D-PTV system was constructed. The measurement system consists of three high-speed high-definition cameras(1k x 1k, 2000fps), Nd-Yag laser(2000Hz) and a host computer. The GA-3D-PTV algorithm was used for completing the measurement system. The 4D-PTV is capable of probing the spatial distribution of velocity vectors of the flow field overcoming the temporal resolution of the characteristic turbulence length scales of the measured flow fields. A horizontal impinged jet flow (H/D=7) was measured. The Reynolds number is about 33,000. Spatial temporal evolution of the jet flow was examined and physical properties such as spatial distributions of vorticity and turbulent kinetic energy were obtained with the constructed.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.907-908
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• 2006

The energy storage systems are being widely researched for the electric power. The operations running in a vacuum chamber mainly consists of a composite flywheel rotor, superconductor bearings, a motor/generator and its controller. Among composed the apparatus, the floating magnet bearing consists of the ring-type permanent magnets with epoxy resin impregnation for reinforcement and surface protection. In order to storage as much energy as possible, the flywheel is supposed to be rotated with very high speed. The magnetic field is analyzed by using the Maxwell 2D/3D for the simulations.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.5
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• pp.343-356
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• 1991

An efficient real-time implementation of digital filtering algorithms using a multiprocessor system in a ring network is investigated. The development time and cost for implementing a high speed signal processing system can be considerably reduced because algorithm are implemented in software using commercially available digital signal processors. This method is based on a parallel block processing approach, where a continuously supplied input data is divided into blocks, and the blocks are processed concurrently by being assigned to each processor in the system. This approach not only requires a simple interconnection network but also reduces the number of communications among the processors very much. The data dependency of the blocks to be processed concurrently brings on dependency problems between the processors in the system. A systematic scheduling method has been developed by using a processors which can be used efficiently, the methods for solving dependency problems between the processors are investigated. Implementation procedures and results for FIR, recursive (IIR), and adaptive filtering algorithms are illustrated.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.650-652
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• 2000

Proposed slotless PM machine is constructed without stator winding slots. Its stator magnetic material is in the form of a ring and winding have a toroidal configuration and its rotor consists of a 4-pole Halbach array or radially magnetized PM rotor. Thus, airgap flux density distribution and induced emf waveform are essentially sinusoidal. Open circuit magnetic fields and developed torque of each type are presented from the analytical method and finite element method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.5
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• pp.786-793
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• 1987

This paper describes the design and fabrication of the polysilicon selfaligned bipolar transistor with 1.6\ulcorner epitaxy and SWAMI isolation technologies. This transistor has two levels of polysilicon. Also emitter and adjacent edge of polysilicon base contact of this PSA device are defined by the same mask, and emitter feature size is 2x4 \ulcorner. DC characteristic of the fabricated transistor was evaluated and analyzed for the SPICE input parameters. The minimum propagation delay time per gate of 330 ps at 1mW was obtained with 41 stage CML ring oscillator.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.560-564
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• 2004

The optimal design and combustion analysis of the gas generator for Liquid Rocket Engine (LRE) were performed. A fuel-rich gas generator in open cycle turbopump system was designed for 10ton$_{f}$ in thrust with RP-1/Lox propellant. The optimal design was done for maximizing specific impulse of main combustion chamber with constraints of combustion temperature and power matching required by turbopump system. Design variables were selected as total mass flow rate to gas generator, O/F ratio in gas generator, turbine injection angle, partial admission ratio, and turbine rotational speed. Results of optimal design show the dimension of length, diameter, and contraction ratio of gas generator. Also, the combustion test was conducted to evaluate the performance of injector and combustion chamber. And the effect of the turbulence ring was investigated on the mixing enhancement in the chamber.r.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.5
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• pp.339-343
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• 1999

This paper reports the characteristics of poly-Si TFT unitary CMOS circuits fabricated with various techniques, in order to investigate the optimum process conditions. The active films were deposited by PECVD and LPCVD using $SiH_4\; and\; Si_2H_6$ as source gas, and annealed by SPC and ELA methods. The impurity doping of the oource and drain electrodes was performed by ion implantation and ion shower. In order to investigate the AC characteristics of the poly-Si TFTs processed with various methods, we have examined the current driving characteristics of the polt-Si TFT and the frequency characteristics of 23-stage CMOS ring oscillators. Ithas been observed that the circuits fabricated using $Si_2H_6$ with low-temperature process of ELA exhibit high switching speed and current driving performances, thus suitable for real application of large area electronics.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3184-3186
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• 1999

In this paper, a new structure of fully differential delay cell VCO using quadrature phase for low phase noise and high speed operation is suggested. It is realized by inserting voltage clamp circuit into input pairs of delay cells that include three-control current source having high output impedance. In this reason. this newly designed delay cell for VCO has the low power supply sensitivity so that the phase noise can be reduced. The whole characteristics of VCO were simulated by using HSPICE and SABER. Simulation results show that the phase noise of new VCO is quite small compared with conventional fully differential delay cell VCO and ring oscillator type VCO. It is also very beneficial to low power supply design because of wide tuning range.

• Journal of the Korean Society of Safety
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• v.11 no.4
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• pp.64-71
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• 1996

Detonation phenomena of $C_2H_2$were invesgated using the various shock tube. To study the detonation characteristics according to the composition of $C_2H_2-0_2$$_2$ and $C_2H_2$-air mixtures, the composition were varied from 5 to 90% and 5 to 50% of acetylene each other. A spiral ring was installed in the shock tube to study the effect of obstacles in DDT phenomena. Detonation velocities were measured using the photodiode, and the DDT phenomena was visualized using the high speed schlieren photograph. From the experimental result, it was found that the detonation velocity was most high near the 1. 8times the stoichiometric ratio of acetylene. And from the visualization of DDT phenomena, it was found that the detonation wave was strengthened throuth the pile up of small compression wave of burned gas. And the obstacles in shock tube accelerate the detonation reaction by turblent effect of flammable gas mixture.