• Journal of the Korean Society of Industry Convergence
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• v.10 no.4
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• pp.221-226
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• 2007

Viscous flow around a front end cooling fan of the car is numerically investigated. The Navier-Stokes equations and the continuity equation are solved in the flow domain. The Reynolds stresses are modelled using the $k-{\varepsilon}$ turbulence model. The governing equations are discretized with the Finite Volume Method. The pressure and the velocity are linked with the SIMPLE algorithm. Flow and pressure characteristics around the fan are investigated. The pressure sharply increases through the fan blade. Pressure variations on the pressure and suction sides of the fan are well represened in the calculations. The flow streamlines in the blade passage are nearly parallel to the blade, but the slope of streamlines increases near the tip.

• International Journal of Automotive Technology
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• v.5 no.3
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• pp.173-180
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• 2004

An intensive study was conducted for the crash worthy structural design of the recently developed Korean High Speed Train (KHST). Two main design concepts were set up to protect both crews and passengers from serious injury in heavy collision accidents, and to reduce damage to the train itself in light collision accidents. A collision against a movable 15-ton rigid obstacle at 110 kph was selected from train accident investigations as the accident scenario for the heavy collisions. A train-to-train collision at the relative velocity of 16 kph was used for the light collision. The crashworthiness behaviors of KHST were numerically evaluated using FEM. Analysis results using 1-D collision dynamics model of the full rake consist and 3-D shell element model of the front end structure showed good crashworthy responses in a viewpoint of structural design. Occupant analyses and sled tests demonstrated that KHST performed well enough to protect occupants under the considered accident scenarios. Finally our numerical approaches were evaluated by a real scale collision test.

• Journal of Advanced Navigation Technology
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• v.4 no.1
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• pp.1-10
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• 2000

When the magnetron is employed as a radar transmitter source, the receiver needs to detect the frequency and the phase of the transmitting signal for the coherent operation. The local oscillator frequency is tuned for the stable intermediate frequency and the coherent oscillator generates the stable signal which is phase-locked to the transmitting signal. In this paper, we designed and implemented the receiver front-end including AFC(Automatic Frequency Control) circuit, STALO(Stable Local Oscillator) and COHO (Coherent Oscillator) unit.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.732-737
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• 2004

TTX(Tilting Train Express), which has improved traveling performance on curved track, is being designed in cope with future railway circumstance. Nowadays, in the world, many efforts are focussed on railway safety. Especially, a variety of researches on train crashworthiness have been conducted. As a part of these efforts, some equipments on TTX are designed to reduce fatalities and casualties in crash accidents. This paper introduces impact energy absorbtion characteristics on the initial design of the front end structure. Some comments are made briefly for improvement of initial structural design and future following researches.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.231-233
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• 2005

For the low-power design of the mobile multimedia system architecture, this paper modeling the mobile multimedia system and analysis the power consumption profile about the whole communication environment. The mobile system model consist of air interface, RIP front-end, base-band processing module and human interface. For the result of power consumption profile analysis, the power consumption of multimedia processing is above 60% compare to the whole power consumption in mobile multimedia system. To minimize the power consumption in processing module which consumes the large power, this paper proposed the Microscopic DVS technique which applies the optimum voltage for the each multimedia frame. For the simulation result, proposed power minimization technique reduce the power consumption about 30%.

• Journal of Mechanical Science and Technology
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• v.15 no.2
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• pp.180-191
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• 2001

The widely used spot welded sections of automobiles(hat and double hat shaped section members) absorb most of the energy in a front-end collision. The sections were tested with respect to axial static(10mm/min) and quasi-static(1000mm/min) loads. Based on these test results, specimens with various thicknesses, width ratios and spot weld pitches on the flange were tested at high impact velocity(7.19m/sec and 7.94m/sec) which simulates an actual car crash. Characteristics of collapse have been reviewed and structures for optimal energy absorbing capacity is suggested.

• Journal of the Korean Society for Railway
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• v.1 no.1 s.1
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• pp.1-9
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• 1998

Described in this paper is the result of a study on collision analysis of TGV-K using 1-dimensional model for crashworthy design. Crashworthy design of the front end is very important because majority of the impact energy (more than 70%) is absorbed by the crush of the front end when the train is collided with an obstacle like a tank lorry. Guideline for the crashworthy design can be described from the collision analysis of the whole train using a 1-dimensional model. Since the headstock of TGV-K is not designed in a crashworthy point of view, a conceptual design of the headstock to improve crashworthiness is suggested and evaluated using 1-dimensional collision analysis. The suggested design, which adopts an energy absorber and a crashworthy headstock, shows a good behaviour on the accident scenario of SNCF (collision at 110 km/h against a movable rigid mass of 15 ton).

• Journal of the Korea Society for Simulation
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• v.21 no.2
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• pp.41-50
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• 2012

In this study we first explain details of the semiconductor manufacturing processes and cluster tools. Then we discuss the problems in current fab layout and cluster tool architecture. As a solution to these problems, we propose the ILE (In-Line EFEM) architecture in which wafer movements are conducted through interconnected EFEMs (Equipment Front End Modules) instead of AMHS (Automated Material Handling System). Then we model the pilot ILE system using discrete event simulation and analyze the cycle time. Finally we compare three different scenarios of equipment layout in the ILE system in terms of cycle time.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.2
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• pp.52-56
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• 2012

Recently, the pedestrian protection regulations of Europe and Japan are becoming more stringent. However, it is difficult to evaluate the performance of protection because each regulation has different test conditions such as dummy, impact speed and so on. In this study, we construct a finite element model of pedestrian lower legform impactor prescribed in EEVC (European Experimental Vehicle Committee) W/G 10, and performed a impact analysis between the impactor and the front end module of vehicle. The simulations are carried out by using LS-DYNA3D, which is a well-known nonlinear dynamic simulation software. The analysis results according to various impact location show the impact characteristics of the lower legform.

• Proceedings of the KSPS conference
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• 1996.10a
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• pp.464-467
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• 1996

This paper aims to exploit inter/intra-speaker phoneme sub-class variations as criteria for adaptation in a phoneme recognition system based on a novel neural network architecture. Using a subcluster neural network design based on the One-Class-in-One-Network (OCON) feed forward subnets, similar to those proposed by Kung (2) and Jou (1), joined by a common front-end layer. the idea is to adapt only the neurons within the common front-end layer of the network. Consequently resulting in an adaptation which can be concentrated primarily on the speakers vocal characteristics. Since the adaptation occurs in an area common to all classes, convergence on a single class will improve the recognition of the remaining classes in the network. Results show that adaptation towards a phoneme, in the vowel sub-class, for speakers MDABO and MWBTO Improve the recognition of remaining vowel sub-class phonemes from the same speaker