• 자원환경지질
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• 제29권4호
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• pp.509-522
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• 1996

A total of 460 palaeomagnetic samples was collected from the Tertiary Chongja-Ulsan basins and surrounding area in the southeastern part of Korean peninsula. All samples were stepwise demagnetized by either alternating field or thermal method. It was found that most sample-sites have ChRM declination which has been rotated clockwise from the north-south reference direction of Tertiary East Asia, although other two extrusive sample-sites within the Chongja sedimentary basin show counterclockwise rotation of ChRM declination. Fold tests for the site-mean ChRMs of the latter two sites reveal insignificant result and negative result with 95% confidence level, respectively. The amount of the clockwise deflection of declination varies from about $20^{\circ}$ upto about $80^{\circ}$ according to the block to which each sample-site belongs. The amount of the counterclockwise deflection is about $20^{\circ}$. It is concluded that the clockwise ChRM rotation has been caused by dextral simple shearing accompanied by NNW-SSE spreading of the East Sea which has been active until about 16Ma, and that the counterclockwise rotation is a result of sinistral simple shearing associated with WNW-ESE contraction in the Korean Strait-SW Japan region at about 15 Ma.

• 자원환경지질
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• 제29권3호
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• pp.357-367
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• 1996

A total of 113 samples (basalts, tuffs, and siltstones from coal-bearing sediments) was collected from 14 sites of the Tertiary Changgi basin in southeastern Korea, and studied palaeomagnetically. Site-mean declination of the ChRM from 5 sites was found to be deflected clockwise about $30^{\circ}$. Other 5 sites showed no vertical-axis deflection of ChRM direction. In consideration of previous palaeomagnetic data from other Tertiary basins in the vicinity, it is interpreted that the deflection of ChRM directions has been caused by NNW-SSE simple shear associated with the opening of the East Sea, and the time of rotation should be about 16 Ma. Other 2 sites showed counterclockwise deflection of site-mean ChRM. These sites might be located among lager tectonic blocks which were rotating clockwise. AMS (anisotropy of magnetic susceptibility) study revealed $NE{\rightarrow}SW$ directed magnetic lineation at two tuffaceous sites. This might indicate flow direction of tuffs during the time of deposition. Most of the other sites showed load-foliation lying subparallel to the bedding plane. This must have been caused by gravitational loading acted vertically to the strata.

• 융합보안논문지
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• 제7권2호
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• pp.1-8
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• 2007

유한고장수를 가진 비동질적인 포아송 과정에 기초한 모형들에서 잔존 결함 1개당 고장 발생률 (강도함수)은 일반적으로 상수, 혹은 단조증가 및 단조 감소 추세를 가지고 있다. 본 논문에서는 기존의 소프트웨어 신뢰성 모형인 Goel-Okumoto 모형 강도함수를 재조명하고 이 분야에 적용 될수 있는 보다 넓은 왜도와 첨도를 가지는 Burr모형 강도 함수 및 의료정보분야 및 여러 분야에서 널리 사용되는 2모수 카파(Kappa(2)) 분포 모형 강도함수를 제안하여 비교하고자 한다. 수치적인 예에서는 고장 간격시간으로 구성된 NTDS(Naval Tactical Data System)자료를 이용하였고 모수추정 방법은 최우추정법과 일반적인 수치해석 방법인 이분법을 사용하여 모수 추정을 실시하였다. 그리고 모형 설정과 선택 판단기준은 편차 자승합을 이용한 적합도 검정이 사용되었다.

• 한국기계가공학회지
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• 제17권1호
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• pp.122-129
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• 2018

This study conducted a seismic qualification analysis of small savonius style vertical axis wind turbine(VAWT) using finite element method(FEM). The modal analysis was performed on the wind turbine structure to check the occurrence of resonance caused by the rotation of gearbox and windmill blades. Next, it conducted a seismic response spectrum analysis due to horizontal and vertical seismic load of required response spectrum of safe shutdown earthquake with 5 % damping(RRS/SSE 5%) of KS C IEC 61400 and conducted a static analysis due to deadweight and wind load. The total maximum stress of the VAWT structure was calculated by adding the maximum stresses due to each load case using the square root of the sum of the squares(SRSS) method. Finally, the structural safety of the VAWT structure was verified by comparing the total maximum stress and the allowable stress.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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• pp.75-79
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• 2007

To investigate the shear-wave velocity structures of the Korean peninsula, exploded seismic signals were recorded for 120 s along a 294-km WNW-ESE line and 150 s along a 335-km NNW-SSE line in 2002 and 2004, respectively. First arrival times of shear wave were inverted to derive the velocity tomograms. Initial shear-wave 1-D models were built using the initial P-wave velocity models used by Kim et al. and $V_p/V_s$ ratios of the IASP91 model. The raypaths indicate existence of mid-crust interfaces at the depth of 2-3 km and 16 km. The deepest significant interface corresponding to the Moho discontinuity varies in depth from 32 km to 36 km. The refraction velocity along the interface varies from 4.4 km/s to 4.6 km/s. The velocity tomograms also indicate existence of a low-velocity zone at the depth of 7.8 km under the Okchon fold belt.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 특별 심포지엄 논문집
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• pp.43-51
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• 2007

In order to investigate the velocity structure of the southern part of the Korean peninsula, exploded seismic signals were recorded for 120 s along a 294-km WNW-ESE line and 150 s along a 335-km NNW-SSE line in 2002 and 2004, respectively. Velocity tomograms were derived from inverting P-wave and S-wave first arrival times. The raypaths indicate several midcrust interfaces. The shallowest one is at the approximate depth of $2{\sim}3\;km$ with refraction velocities of approximately Vp=6.0 and Vs=3.5 km/s, respectively. The second one of $15{\sim}17\;km$ depth has refraction velocities of approximately Vp=7.1 and Vs=3.7 km/s, respectively. The deepest significant interface varies in depth from 30.8 km to 36.1 km. The critically refracting Vp of $7.8{\sim}8.1\;km/s$ and Vs of $4.2{\sim}4.6\;km/s$ along this interface which may correspond to the Moho discontinuity. The velocity tomograms show (1) existence of a low-velocity zone centered at $6{\sim}7\;km$ depth under the Okchon fold belt and the Yeongnam massif, (2) extension of the Yeongdon fault down to greater than 10 km, and (3) existence of high-velocity materials under the Gyeongsan basin less than 4.2 km thick.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
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• pp.481-488
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• 2001

The HANARO in-chimney bracket was proposed as a structure which supports the guide tubes of irradiation facilities at the irradiation sites of CT, IR and OR4/5 in HANARO core for the reduction of flow-induced vibration and seismic response of the irradiation facilities. For the evaluation of the structural integrity of the in-chimney bracket, its finite element model is developed. The seismic response analysis was performed for the in-chimney bracket and related reactor structures, under the response spectrum of OBE and SSE. The analysis results show that stress values of the in-chimney bracket and reactor structures for the seismic loads are within the ASME code limits. It is also confirmed that its fatigue usage factor is much less than 1.0. For the verification of the implementation effects of the in-chimney bracket, the vibration level of the guide tube of the instrumented fuel assembly, which is subjected to fluid-induced vibration, was measured and analyzed. The vibration analysis results demonstrate that the vibration level of the instrumented fuel assembly has been remarkably reduced after installing the in-chimney bracket. Therefore, when the in-chimney bracket is installed at the reactor chimney, any damage on the structural integrity is not expected.

• 한국광학회지
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• 제11권5호
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• pp.340-346
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• 2000

최근 모드변환기가 집적된 진행파형 반도체 광증폭기(SSC-TW-SOA)가 광섬유와의 광결합 효율 향상 및 저가격화를 위해 활발히 연구되고 있다. 본 연구에서는 모드변환기의 구조가 단면 반사율에 미치는 영향을 실험 및 이론적으로 조사하였다. SSC-TW-SOA의 유효단면반사율을 낮추기 위해서는 수직 및 수평방향으로 충분히 모드변환을 행하고 동시에 기운단면 구조를 채용하는 것이 매우 효과적임을 이론적 및 실험적으로 확인하였다. 수직 및 수평방향의 모드변환기가 집적된 TW-SOA에 $20\mu\textrm{m}$ 길이의 창구조, $7^{\circ}$기운단면, 1% 무반사 코팅을 도입함으로써 0.1dB 이하의 작은 ASE ripple를 얻을 수 있었다.

• 한국건축시공학회지
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• 제2권4호
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• pp.177-182
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• 2002

The purpose of this study is to develope the strength prediction model by Maturity Method. A maturity function is a mathematical expression to account for the combined effects of time and temperature on the strength development of a cementious mixture. The method of equivalent ages is to use Arrhenius equation which indicates the influence of curing temperature on the initial hydration ratio of cement. For the experimental factors of this study, we selected the concrete mixing of W/C ratio 45, 50, 55 and 60% and curing temperature 5, 10, 20 and $30^{\circ}C$. And we compare and evaluate with logistic model that is existing strength prediction model, because we have to verify adaption possibility of new strength prediction model which is proposed by maturity method. As the results, it is found that investigation of the activation energy that are used to calculate equivalent age is necessary, and new strength prediction model was proved to be more accurate in the strength prediction than logistic model in the early age. Moreover, the use of new model was more reasonable because it has low SSE and high decisive factor.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권6호
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• pp.286-295
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• 2006

This paper presents a design of a real-time software GPS receiver which runs on a PC. The software GPS receiver has advantages over conventional hardware based receivers in terms of flexibility and efficiency in application oriented system design and modification. In odor to reduce the processing time of the software operations in the receiver, a shared memory structure is used with a dynamic data control, and the byte-type IF data is processed through an Open Multi-Processing technique in the mixer and integrator which requires the most computational load. A high speed data acquisition device is used to capture the incoming high-rate IF signals. The FFT-IFFT correlation technique is used for initial acquisition and FLL assisted PLL is used for carrier tracking. All software modules are operated in sequence and are synchronized with pre-defined time scheduling. The performance of the designed software GPS receiver is evaluated by running it in real-time using the real GPS signals.