• Earthquakes and Structures
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• 제24권1호
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• pp.53-64
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• 2023

Earth fissures with several kilometers will inevitably approach or cross the metro line, significantly threatening the safety of the underground structure in the earth fissure site. However, the influence of the earth fissure site's amplification effect on the metro station's dynamic response is still unclear. A representative earth fissure in Xi'an was taken as an example to establish a numerical model of a metro station in the earth fissure site. The dynamic response characteristics of the metro stations at different distances from the earth fissure under various seismic waves were calculated. The results show that the existence of the earth fissure significantly amplifies the dynamic response of the nearby underground structures. The responses of the axial force, shear force, bending moment, normal stress, horizontal displacement, inter-story drift, and relative slip of the metro station were all amplified within a specific influence range. The amplification effect increases with the seismic wave intensity. The amplification effect caused by the earth fissure has relatively weak impacts on the axial shear, shear force, bending movement, normal stress, and horizontal movement; slightly larger impacts on the inter-story drift and acceleration; and a significant impact on the relative slip. The influence ranges of the axial force and normal stress are approximately 20 m. The influence ranges of the acceleration and inter-story drift can reach 30 m. Therefore, the seismic fortification level of the underground structure in the earth fissure site needs to be improved.

• 전력전자학회논문지
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• 제4권2호
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• pp.166-174
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• 1999

최적효율제어를 통한 유도전동기의 효율향상은 에너지 절감측면에서 매우 중요하며 인공신경망을 사용하면 시스템의 특성이 충분히 해석되지 않은 상태에서도 우수한 제어특성을 얻을 수 있다. 본 논문은 유도전동기 구동시스템에서 최적 슬립주파수를 추종하는 실시간 인공신경망 회로를 구성하여 운전효율을 최적화하는 제어방법을 제안한다. 제안된 최적 효율제어기는 인공신경망 제어기에 의해 시스템의 비선형성을 포함하여 전동기의 내부손실이 최소가 되는 운전점을 추종한다. 시뮬레이션과 실험을 통하여 기존의 일정v/f 방식에 비하여 고속 경부하시 경제성 있는 에너지 절감효과를 충분히 확보할 수 있었다.

• Journal of Korean Neurosurgical Society
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• 제29권11호
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• pp.1461-1468
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• 2000

Objective : The aim of this study is to evaluate clinical outcome of anterior screw fixation for type II odontoid fractures for the prliematim of atlanatoaxial mobility. Methods : Between 1995 and 1999, we treated 15 cases of type II odontoid fractures by anterior screw fixation among 44 cases of odontoid fractures. Thece included 14 males and 1 female aged from 23 to 63 years, with a mean age of 39.7 years. The causes of trauma were traffic accident in 13 cases, slip down in 1 and fall down in 1. The fracture type was type II-P in 7 cases, type II-A in 3, type II-N in 2 and type II-A and P in 3. The fracture line was oblique downward and backward in 6 cases, oblique downward and forward in 3 and horizontally in 6. The range of follow up was 4 to 47 months(mean 26.5 months). Results : Adequate reduction and fixation were obtained in 12 cases. Three cases in which fracture type and line were type II-A and oblique downward forward were failed, so posterior transarticular screw fixation was performed. All except 3 failed cases had adequate cervical movement and stability. There were no operative mortality nor morbidity. Conclusion : Anterior screw fixation provides the best anatomical and functional results for type II odontoid fracture with intact transverse ligament when fracture line is horizontal or oblique downward and backward. But it is limited when fracture line is oblique downward and forward.

• 조명전기설비학회논문지
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• 제23권3호
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• pp.45-52
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• 2009

Power line communication or power line carrier (PLC) is a system for carrying data on a conductor and can also used for electric power transmission. Now the powers used in the motor drive system are mostly DC sources. Even AC powers in some systems are generated from DC sources by the inverter. It is can be forecasted that the DC-link PLC technology will be widely used in various industrial fields. In this paper a novel BLDC motor control system using ASK DC-link PLC technology is proposed. The characteristic of this system is that the communication only needs 2 DC lines and there are no additional lines to translate the reference signals. The number of signal cables can be minimized when the DC-link PLC method is applied in the multi motor control system and the slip ring design also can be simplified when this method is applied in rotation machines. The proposed motor control system is clarified by the PSIM and MATLAB simulations and tested through the hardware prototype.

• 한국자동차공학회논문집
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• 제18권2호
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• pp.14-23
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• 2010

This paper analyzes braking performance of ABS with Sliding Mode Controller, which is designed in this research and compared with that of a commercial ABS-ECU only. HILS system for this paper has an existing hydraulic brake line with an ECU of commercial passenger vehicle and it is designed to be cooperated with Sliding Mode Controller and hydraulic line. This paper shows the simulation results to meet the target slip ratio on the various road conditions and displays the performance with Sliding Mode Controller has an improvement than a commercial ABS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.612-615
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• 2003

In this paper, a design of radiation detector for gamma column scanner is introduced. Distillation column is important unit in Petro-chemical industries, and its on-line diagnose is very important. To get density profile measured by the radiation transmitted through column is well method for on-line diagnose as gamma scanning. For this purpose radiation detection circuit, radiation source and mechanical system for moving source and detector are required. Conventional radiation detection circuit for this application is sensitive to electric noise because of interface between the radiation circuit and the controller for mechanical system. The radiation detection system introduced here is using loop coil instead of slip ring to remove contact noise. Radiation detection system designed here for gamma scanning consist of BGO detector, high voltage circuit, PHA circuit and FSK modem. The BGO detector is used as radiation sensor, high voltage circuit and peak height analysis circuit is essential to process the signal generated from BGO detector. Micro controller convert measured data into ASCII data. FSK modem transmit ASCII data. Transmitted ASCH data is picked up in antenna coil and processed for combined function with mechanical system. This method gives good result by isolating the controlling circuit of mechanical system from radiation detecting circuit which is sensitive to noise.

• 암석학회지
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• 제23권2호
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• pp.75-103
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• 2014

한반도 남동부 일원에는 주요 지질구조선(양산단층대, 울산단층, 연일구조선, 오천단층계 등)을 따라 제4기 단층들이 도처에 분포하고 있으며, 이들의 기하와 운동학적 특징은 한반도의 제4기 지각변형사와 현생응력상태 등을 이해하는 데 중요한 정보들을 제공한다. 이번 연구에서는 진티단층, 모화단층, 수성지2단층 그리고 왕산단층을 대상으로 대자율이방성 방법을 적용하여 단층가우지의 미세구조를 분석하고 단층의 운동감각을 해석하였으며, 그 결과를 바탕으로 단층암의 미세구조 발달과정과 제4기 응력장에 대해 논의하였다. 대자율이방성 측정을 통해 구해진 자기미세구조로부터 단층의 운동감각을 분석한 결과, 왕산단층을 제외한 나머지 세 단층은 모두 역이동성이 우세한 단층운동에 의한 미세구조가 발달되어 있다. 단층면에 거의 평행한 편평형의 미세구조가 발달하는 점과 이방성정도가 클수록 편평형의 정도가 증가하는 특징에 근거할 때, 단층가우지의 미세구조는 점진적인 변형에 의한 최종응력변형이 기록된 것으로 해석된다. 또한, 최후기에 재활된 역단층운동으로 기존의 단층가우지 내에 존재하는 미세구조들은 모두 지워지고 최후기의 운동에 의한 미세구조만이 기록된 것으로 판단된다. 단층가우지의 자기미세구조 분석을 통해 유추된 운동감각으로부터 구해진 고응력장은 동북동-서남서 방향의 압축력이며, 이 응력장은 지진원 메커니즘, 수압파쇄시험 그리고 단층 지구조분석결과를 통해 구해진 한반도 남동부의 고응력장과 부합된다. 결론적으로 한반도 일원은 제4기 동안 동-서 내지 동북동-서남서 방향의 압축성 응력장이 지배적이었던 것으로 해석된다.

• 한국결정성장학회지
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• 제9권6호
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• pp.535-541
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• 1999

Low-dislocation-density large-diameter GaAs single crystals with low-residual-strain have been strongly required. We have developed dislocation-free 3-inch Si doped GaAs crystals for photonic devices, and low-dislocation-density low-residual-strain 4-inch to 6-inch semi-insulating GaAs crystals for electronic devices by Vertical Bridgman(VB) technique. We confirmed that VB substrates with low-residual-strain have higher resistance against slip-line generation during MBE process. VB-GaAs single crystals show uniform radial profile of resistivity reflecting to the flat solid-liquid interface during the crystal growth. Uniformity of micro-resistivity of VB-GaAs substrate is much better than of the LEC-GaAs substrate, which is due to the low-dislocation-density of VB-GaAs single crystals.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.37-42
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• 2004

This paper presents a simple method to estimate fully plastic crack tip stresses of unequally notched specimen based on the equilibrium condition of the least upper bounds for plane strain deformation fields. The method is applied to unequally notched specimens under bending and tension. For various notch angle the limit loads and crack tip stresses are estimated from the present method and compared with results from finite element limit analyses.

• 한국자동차공학회논문집
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• 제6권2호
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• pp.1-11
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• 1998

The 4WS system is usually developed to improve the maneuverability at low speed and the straight line stability at high speed, but it is found to have the severe understeer characteristics at high speed. Therefore a 4WS vehicle requires to turn the steering wheel much more than a 2WS vehicle at high speeds even a driver goes through the same curved road. In this study, to enhance the cornering performance of the 4WS vehicle at high speed, a DYC 4WS system is proposed based on the nonlinear 4WS system and direct yaw moment control system. Especially the proposed DYC 4WS system is able to realize a zero side slip angle for vehicles and a cornering performance similar to the 2WS vehicle at high speed.