• Journal of the Korean Institute of Gas
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• v.21 no.4
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• pp.70-75
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• 2017

This paper presents the FEM analysis results on the deformation behavior safety of automatic cut-off horizontal and conventional vertical gas valves. Based on the FEM analysis, the primary maximum deformation of $4.4{\mu}m$ was formed on the right end side of a valve body when the internal gas pressure was supplied on the screw port and gas discharge port of an automatic cut-off horizontal gas valve. And the secondary maximum deformation of $2.9{\mu}m$ was formed on the end side of safety valve port. This small deformation of an automatic cut-off horizontal gas valve is strongly related to the balanced design of a horizontal gas valve main body, which is composed of a screw part, gas outlet port, port for a stem and spindle shaft assembly, and safety valve port. But, the primary maximum deformation of 0.076mm was formed on the upper part of a conventional automatic cut-off vertical gas valve when the internal gas pressure was supplied on the screw port and gas discharge port. And the secondary maximum deformation of 0.055mm was formed on the left end side of a gas outlet port. This may effect on the sealing clearance of o-ring that is inserted on the groove of an automatic cut-off unit. Thus, this paper recommends an automatic cut-off horizontal gas valve compared with that of a conventional gas valve for a gas leakage free mechanism of a LPG cylinder valve.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.1
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• pp.84-91
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• 2003

The equipment of textiles let off is a part of inspection machine which inspects finished textiles and it checks up textiles through that. This study suggests a method to select the capacity and initial gas pressure of accumulator to control surge rising pressure occurring when suddenly braking action to a desired degree. An accumulator in hydraulic systems is by hydraulic machinery which stores kinetic energy of inertia body during braking. A series of computer simulations were done for the brake action The results of the simulation work were compared with those of experiments.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2295-2296
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• 2008

본 논문에서는 에너지 절감을 위하여 POWER LED 구동회로를 PIR(Pyroelectric Infrared Ray) 센서를 이용하여 ON/OFF 제어를 하였다. POWER LED의 전류 특성을 설명하였으며 설명된 전류 특성을 개선하고자 정전류 유지 회로를 구성하였다. 그리고 인체 감지 센서에서 발생되는 ON/OFF 신호를 증폭시키는 구동 회로를 설계하여 정전류 유지 회로에 직접 결합하는 방식을 제안하였다. 실험한 결과는 POWER LED의 ON 상태시 4Watt, OFF 상태시 0.5Watt를 소비하였으며, 정전류 유지 회로에 의해 POWER LED 구동 전류의 리플이 줄어들어 안정적인 동작을 하는 것으로 나타났다.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.377-380
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• 2001

The vestibular system located in the inner ear controls reflex body posture and movement. It has the semicircular canals sensing an angular acceleration and the otolith organs sensing a linear acceleration. With this organic signal, medical doctor decide if a person has disease or not. To obtain this data, a precision stimular system is considered. Robust control is needed to obtain eye signals induced by off-vertical axis rotation because of an unbalanced load produced by tilting the axis of the system upto 30 degrees. In this study, off-vertical axis rotatory system with visual stimulation system are developed. This system is consisted of head mounted display for generating horizontal, vertical, and three dimensional stimulus patterns. Furthermore wireless recording system using RF modem is considered for noiseless data transmission.

• International Journal of Automotive Technology
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• v.6 no.5
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• pp.483-489
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• 2005

Based on a two-degree of freedom vehicle model, this paper investigates ride comfort for a heavy off-road vehicle mounted a nonlinear hydropneumatic spring, which is influenced by nonlinear stiffness and damping characteristics of the hydropneumatic spring. Especially, the damping force is derived by applying H. Blasius formula in modeling process according to the real physical structure of the hydropneumatic spring, and the established model of nonlinear stiffness characteristics have been validated by experiments. Furthermore, the effects of parameter variations of the hydropneumatic spring, such as initial charge pressure and damping coefficient, on body acceleration, suspension deflection and dynamic tire deflection are also investigated.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.118-126
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• 2003

Digital Manufacturing is a technology facilitating effective developments and agile productions of the product via digital computer models representing physical and logical schema and the behavior of the real manufacturing systems including manufacturing resources, environments and products. For the successful application of this technology, a digital factory as a well-designed and an integrated environment is essential. In this paper, we constructed the sophisticated digital factory of a Korean automotive company's body shop, and conducted precise simulations of unit cell, lines and the whole factory for the collision check, the production flow analysis and the off-line programming. We expect that this digital factory of the body shop helps us achieve great savings in time and cost for many manufacturing preparation activities of the new car development.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1462-1464
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• 1998

Poly-Si TFT(Thin Film Transistor) is a electronic device that can be applied to the field of large area electronics such as AMLCD. We have fabricated the poly-Si TFT with lateral body terminal that is counter-doped body electrode and investigated the electrical characteristics of it. The lateral body terminal being short with s terminal, we have measured the transfer charac (Vg-ld) and the output characteristic (Vd-ld) fabricated devices. The measured result showe only that leakage current in OFF-state was re and Kink effect in ON-state was suppressed bu that in output characteristic curve the output Id was sustained constantly with the output v Vd in the saturation region.

• Journal of applied mathematics & informatics
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• v.15 no.1_2
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• pp.127-146
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• 2004

In this paper we consider a heat flow in an inhomogeneous. body without internal source. There exists special initial and boundary conditions in this system and we intend to find a convenient coefficient of heat conduction for this body so that body cool off as much as possible after definite time. We consider this problem in a general form as an optimal control problem which coefficient of heat conduction is optimal function. Then we replace this problem by another in which we seek to minimize a linear form over a subset of the product of two measures space defined by linear equalities. Then we construct an approximately optimal control.

• International Journal of Safety
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• v.7 no.1
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• pp.26-29
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• 2008

The purpose of this study is the measurement of whole-body vibration for different road surfaces. Experimental measurements were taken on asphalt, cement, and off-road surfaces as defined by ISO 2631-1. Each experiment was conducted under the same set of conditions (measurement duration, times, speed, vehicle type). Measurement duration was 10 minutes and 3 separate measurements were taken on each road surface. Vehicle speed was 60km/h. In accordance with ISO 2631-1, an acceleration sensor is set up between the driver's seat and the human body. For evaluation, RMS(root-mean-square) values were taken as suggested by ISO 2631-1. The results suggest "health guidance caution zones", and the evaluation was based on obtaining the vector sum with "health guidance caution zones".

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.1
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• pp.53-58
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• 2002

New nondestructive inspection (NDI) technique to detect the defect in metal was developed in which an electromagnetic field is induced in a metal by AC current flowing in the magnetic coil and the leak magnetic-flux disturbed by defects is measured using a tape-recorder head with air gap. This technique can be applied in evaluating the location and sizing of surface defects in components of the ferromagnetic body by means of the non-contacting measurement. In this paper, we have applied this technique to the evaluation of two-dimensional surface cracks in ferromagnetic metal, and also investigated the influence of the various frequencies and lift-off. Defects were detected with maximum values in the distribution of voltage and it was found that the maximum values tend to increase with the defect depth. Although the maximum values for defects are affected by the frequency and lift-off, the depth of small defects can be estimated from the linear relationship between the depth and voltage rate$(V_0/V_{ave})$.