• The Journal of the Petrological Society of Korea
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• v.25 no.3
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• pp.169-193
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• 2016

In order to characterize the Neotectonic crustal deformation and current stress field in and around the Korean Peninsula and to interpret their tectonic implications, this paper synthetically analyzes the previous Quaternary fault and focal mechanism solution data and recent geotechnical in-situ stress data and examines the characteristics of crustal deformations and tectonic settings in and around East Asia after the Miocene. Most of the Quaternary fault outcrops in SE Korea occur along major inherited fault zones and show a NS-striking top-to-the-west thrust geometry, indicating that the faults were produced by local reactivation of appropriately oriented preexisting weaknesses under EW-trending pure compressional stress field. The focal mechanism solutions in and around the Korean Peninsula disclose that strike-slip faulting containing some reverse-slip component and reverse-slip faulting are significantly dominant on land and in sea area, respectively. The P-axes are horizontally clustered in ENE-WSW direction, whereas the T-axes are girdle-distributed in NNW direction. The geotechnical in-situ stress data in South Korea also indicate the ENE-trending maximum horizontal stress. The current crustal deformation in the Korean Peninsula is thus characterized by crustal contraction under regional ENE-WSW or E-W compression stress field. Based on the regional stress trajectories in and around East Asia, the current stress regime is interpreted to have resulted from the cooperation of westward shallow subduction of the Pacific Plate and collision of Indian and Eurasian continents, whereas the Philippine Sea plate have not a decisive effect on the stress-regime in the Korean Peninsula due to its high-angle subduction that resulted in dominant crust extension of the back-arc region. It is also interpreted that the Neotectonic crustal deformation and present-day tectonic setting of East Asia commenced with the change of the Pacific Plate motion during 5~3.2 Ma.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.06a
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• pp.62-68
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• 2002

In this paper, we have developed the Up-Convertor for CATV Head/End using 54∼750 MHz. We have individually designed and fabricated the main circuit of Up-converter such as Amplifier, frequency mixer, Voltage Controlled Oscillator(OSC), and we have realized the implementation for System Module in each circuit, so we have achieved a small size, light weight. and we have focused to have a shielding technique in high frequency bandwidth.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.431-432
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• 2017

본 논문은 자유 피스톤 엔진에 적용되는 단상 선형발전기용 전력제어시스템에 관한 연구이다. 자유 피스톤 엔진 선형발전시스템은 피스톤의 움직임을 구속하는 기구가 없기 때문에 기계적 마찰 손실이 적고 상사점 도달 시간이 짧아 에너지 효율측면에서 기존의 피스톤 엔진보다 유리한 기술이다. 하지만, 자유 피스톤 엔진의 경우 초기 기동 할 수 있는 동력원이 필요하며, 단상 선형 발전기의 경우 짧은 스트로크 및 낮은 속도로 인해 인덕턴스가 크게 설계 되어, 높은 인덕턴스로 인한 전류의 위상 지연으로 역률이 낮아지게 되고, 응답성이 떨어지는 문제점을 가지고 있다. 이러한 문제점을 해결하기 위해 본 논문에서는 역률 보상 및 응답성을 높일 수 있는 자유피스톤 엔진용 단상선형발진기용 전력제어시스템을 제안한다.

• Journal of Navigation and Port Research
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• v.33 no.10
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• pp.699-702
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• 2009

Currently many vessels determine an overhead obstruction by a rule of thumb based on their draft for maritime navigation. Therefore they doesn't have a good overhead obstruction clearance because vertical position of vessels varies on time by tidal. As a result, it is occurred maritime accidents that the mainmast of vessels is bumped against overhead facilities. And disaster by global warming and rising sea levels have increased casualties. So we feel keenly the necessity of warning system for not an earthquake but disaster wave such a tsunami. This paper analyzes a precise GPS ephemeris for maritime precise positioning to solve these problems. The precise GPS ephemeris provided by International GNSS service gives a difficulty to real-time application because of its sample interval. This paper proposes an effective interpolation method for real-time application, and it analyzes an accuracy of precise GPS ephemeris through an interpolation method.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.586-587
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• 2012

자동차 산업에 있어서 반도체 기술발전과 더불어 차량 내 기능들이 효율성, 경제성 및 친환경적인 관심을 고려하여 기계식 방식에서 전력전자식 방식으로 대체되고 있는 실정이다. 엔진의 연비를 향상시키기 위해서는 엔진의 연소효율을 개선하거나, 엔진에서 발생되는 손실을 줄이는 것이 필요한데, VVA(Variable Valve Actuation, 가변 밸브 작동) 기술은 엔진 흡기 유동 강화, 펌핑 손실 저감, 기계적 마찰 손실 저감등을 통해 엔진의 연비를 향상시킬 수 있다. 또한 VVA 엔진을 장착한 차량은 차량의 발진 응답성이 향상되고, 배기가스 배출량을 줄일 수 있어 친환경 저연비 차량을 실현하는데 핵심 차량부품기술이다. 최근까지 차량의 전동기 구동의 경우 DC모터 방식이 많이 적용되어 왔으나 DC모터의 내구성 및 효율 등의 이유로 BLDC모터로 바뀌고 있는 추세이다. 본 논문에서는 이와 같은 VVA 기구의 적용을 위하여 BLDC모터 제어기를 개발하였다.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.235-242
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• 2010

Two moderate earthquakes with local magnitude 4.9 and 5.0 at the Yellow Sea area occurred successively around Hong island on March 22, 2003 and Baengnyeong island on March 30, 2003, respectively, close to the Korean Peninsula. Focal mechanisms by the waveform inversion analysis are strike slip faulting with a thrust component for the March 22 event, and normal faulting for the March 30 event. The direction of P-axes of two events were ENE-WSW which were similar to previous studies on that of P-axes in and around the Korean Peninsula. Moment magnitudes determined by the waveform inversion analysis were 4.7 and 4.5, respectively, whereas those determined by spectral analysis were 4.8 and 4.6, respectively. As regards the March 22 event, regional stress by combined tectonic forces from compressions of plates colliding to the Eurasian plate, rather than mere local stress, was indicated. However, it was estimated that the March 30 event took place when the weak zone generated from the existing collision zone was reactivated when subjected to local stress in the tensile direction. This seismological observation indirectly supports the idea that the collision zone may extend to the Korean Peninsula.

• Journal of Biosystems Engineering
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• v.12 no.1
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• pp.45-52
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• 1987

In order to improve the thermal efficiency of an internal combustion engine, various ignition timing control systems were examined and the best one was chosen. The parts used for the systems were a microcomputer system with DAS, 8 bit output port (D-FLIP FLOP), three types of isolation circuit, two types of ignition timing pulse generator, three types of switching circuit and two types of high voltage ignition circuit. Most systems did not operate well due to the effects of electromagnetic waves and surge currents occurring when the ignition began or ended with resulting high voltage. The best ignition timing control system was found to be the combination of (microcomputer system)-(ignition timing pulse generator using step motor position control pick-up)-(switching circuit using TR logic)-(high voltage ignition circuit using CDI).

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.91-96
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• 2020

The 33-mode dielectric and piezoelectric properties of Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 piezoelectric single crystals were measured under large electric field and compressive stress. The phase transition from the low temperature rhombohedral to the high temperature tetragonal structure was observed in the range of 110~140℃, and the Curie temperature changing to the cubic structure was about 165℃. The polarization change according to the compressive stress and electric field was measured. Relative dielectric constant was calculated from the slope of the polarization curve applied to the electric field, and the calculated relative dielectric constant increased as the applied stress increased, and the relative dielectric constant decreased as the applied electric field increased. The strain according to the compressive stress and electric field change was measured, the piezoelectric constant was calculated from the slope of the curve, and the phase transition according to the application of pressure was confirmed. In the case of practical application as an underwater or medical ultrasonic actuator, it is necessary to properly design the magnitude of the compressive stress applied to the device and the DC bias in order to maintain linear driving.