• 한국지진공학회논문집
• /
• 제11권4호
• /
• pp.53-63
• /
• 2007

Seismic design codes are developed mainly based on the observation of the behavior of structures in the high seismicity regions where structures may experience significant amount of inelastic deformations and major earthquakes may result in structural damages in a vast area. Therefore, seismic loads are reduced in current design codes for building structures using response modification factors which depend on the ductility capacity and overstrength of a structural system. However, structures in low seismicity regions, subjected to a minor earthquake, will behave almost elastically because of the larger overstrength of structures in low seismicity regions such as Korea. Structures in low seismicity regions may have longer periods since they are designed to smaller seismic loads and main target of design will be minor or moderate earthquakes occurring nearby. Ground accelerations recorded at stations near the epicenter may have somewhat different response spectra from those of distant station records. Therefore, it is necessary to verify if the seismic design methods based on high seismicity would he applicable to low seismicity regions. In this study, the adequacy of design spectra, period estimation and response modification factors are discussed for the seismic design in low seismicity regions. The response modification factors are verified based on the ductility and overstrength of building structures estimated from the farce-displacement relationship. For the same response modification factor, the ductility demand in low seismicity regions may be smaller than that of high seismicity regions because the overstrength of structures may be larger in low seismicity regions. The ductility demands in example structures designed to UBC97 for high, moderate and low seismicity regions were compared. Demands of plastic rotation in connections were much lower in low seismicity regions compared to those of high seismicity regions when the structures are designed with the same response modification factor. Therefore, in low seismicity regions, it would be not required to use connection details with large ductility capacity even for structures designed with a large response modification factor.

• 한국인구학
• /
• 제35권1호
• /
• pp.31-52
• /
• 2012

본 연구는 그 동안 한국에서 시행되고 있는 저출산 관련 주요 정책의 효과성에 대한 분석을 시도하고자 한다. 이를 위해 저출산 관련 시책에 대한 인지도와 경험도를 검토하였으며, 이러한 인지도와 경험도가 자녀의 출산계획에 미치는 영향을 분석하였다. 분석 결과 현존 자녀수를 고려하지 않을 경우 경제적 지원 정책과 양성평등 문화조성에 대한 인지도는 출산계획의 가능성을 높이는 것으로 나타났다. 그러나 이러한 결과는 현존 자녀수별로 분석할 경우 다르게 나타난다. 즉 무자녀 기혼여성들의 경우 저출산 관련 대책들에 따른 자녀출산계획의 차이는 없는 것으로 나타난다. 1자녀 기혼여성의 저출산 관련 지원정책에 대한 인지도가 추가출산계획에 미치는 영향도 모두 통계적으로 유의하지 않은 것으로 나타난다. 2자녀 여성의 경우에도, 저출산 정책에 대한 인지도가 추가출산계획에 미치는 영향은 유의하지 않은 것으로 나타났다. 이러한 결과는 저출산 정책의 이용도의 경우에도 동일한 패턴으로 나타난다. 즉 현존 자녀수를 고려하지 않을 경우 경제적 지원, 일 가정 양립 지원, 양성평등 문화조성 등은 출산계획에 통계적으로 유의한 영향을 주는 것으로 나타난다, 그러나 현존 자녀수별로 분석을 진행할 경우 이러한 변수들의 통계적인 유의성은 사라져 저출산 정책의 이용경험은 모두 출산계획에 유의한 영향을 주지 않는 것으로 나타났다. 이러한 결과는 저출산 정책을 수리할 때 자녀수에 대한 고려가 필수적임을 보여주는 것이다. 이와 함께 저출산 관련 지원정책의 효과가 뚜렷하게 나타나기 위해서는 보다 실질적이고 체계적인 저출산 대책이 지속적으로 추진되어야 한다는 점을 반영한 것으로 보인다.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2002년도 추계 학술발표회 논문집
• /
• pp.35-42
• /
• 2002

Frequency responses for most of the local seismic sensors in Korea have been roughly checked by mutual comparison of Fourier spectra of seismic records from accelerometer and seismometer, both of which are installed at the same location. Especially, because the frequency content of the seismic energy is usually above 1 Hz for local earthquakes, the reliability of low frequency response could have not been evaluated. Fortunately a recent large earthquake, Ms=7.2 on 02/06/29 containing dominant low frequency energy makes it possible to check the low frequency response of the seismic sensors, especially EpiSensor and JC-V100. Considering two types of sensor pairs, (STS-2 and EpiSensor, JC-V100 and EpiSensor), the low frequency response of EpiSensor is confirmed first by comparison with STS-2 which has proved low frequency response. Second, reliable low frequency limit of instrumentally corrected seismic data from JC-V100 data is estimated to be about 0.03 Hz by comparison with EpiSensor data.

• 한국지진공학회논문집
• /
• 제22권2호
• /
• pp.77-86
• /
• 2018

This study develops an empirical prediction equation of spectral acceleration responses of earthquakes which can induce structural damages. Ground motion records representing hazards of low-to-moderate seismic regions were selected and organized with several influential factors affecting the response spectra. The empirical equation and estimator coefficients for acceleration response spectra were then proposed using a robust nonlinear optimization coupled with a regression analysis. For analytical verification of the prediction equation, response spectra used for low-to-moderate seismic regions were estimated and the predicted results were comparatively evaluated with measured response spectra. As a result, the predicted shapes of response spectra can simulate the graphical shapes of measured data with high accuracy and most of predicted results are distributed inside range of correlation of variation (COV) of 30% from perfectly correlated lines.

• Journal of Advanced Marine Engineering and Technology
• /
• 제24권6호
• /
• pp.110-119
• /
• 2000

In this paper, an experimental study is carried out under the operating conditions of low speed and rapid acceleration in order to investigate and improve the response characteristics of a turbocharged diesel engine with radial turbine driven by exhaust gas. A rapid acceleration for investigating the response performance is applied to the fuel-pump rack of the engine from 0-10% to 0-40% in steps of 10%, and accelerating time of 1, 2 and 3 seconds is applied to the engine. Further experiment for improving the low speed torque and acceleration performance is also performed by means of injecting air into the inlet manifold at compressor exit during the period of low speed and application of a rapid acceleration. The effects of air injection on the response performance are represented at subjected engine speed with the changes of response performance factors such as air injection pressure, air injection period, accelerating rate, accelerating time and load. From the experimental results obtained throughout this study, it is shown that air injection into the inlet manifold at compressor exit is closely related to the improvement of low speed and acceleration performance of a turbocharged diesel engine.

• 한국안광학회지
• /
• 제17권1호
• /
• pp.75-81
• /
• 2012

목적: 양안개방형 자동굴절검사기를 이용하여 완전교정과 저교정 상태에서 실제 일어나는 조절 반응량을 측정하여 조절의 변화를 알아보고자 하였다. 방법: 20~30세($21.14{\pm}2.00$세)의 대학생 79명(남 58명, 여 21명)을 대상으로 타각적 자각적 굴절검사를 실시하여 완전교정은 시력이 1.0일 때, 저교정은 임의적으로 플러스 렌즈를 부가하여 0.8, 0.7, 0.6일 때의 조절 반응량을 5.0 m, 1.0 m, 0.50 m, 0.33 m, 0.25 m에서 측정하였다. 피검사자를 대상으로 주시거리에 따른 1.0, 0.8, 0.7, 0.6 시력 상태에서 조절 반응량의 변화를 비교 분석하였다. 결과: 우안 좌안 모두 완전교정 상태(1.0)가 저교정 상태(0.7) 보다 조절 반응량의 값이 크게 나타났다(p=0.000). 완전교정 상태가 저교정 상태(0.7) 보다 주시거리가 짧아질수록 조절 반응량의 변화가 더 크게 나타났다. 주시거리에 따른 시력과 조절 반응량의 상관관계는 거리가 짧을수록 더 낮게 조사 되었다. 결론: 장시간 근거리 작업은 조절기능에 영향을 줄 수 있으므로 저교정을 하여 눈의 안위를 편안하게 하는 것이 안정피로 증상을 해소하는데 도움이 될 것이다.

• Structural Engineering and Mechanics
• /
• 제20권4호
• /
• pp.451-463
• /
• 2005

Structural members commonly employed in marine and off-shore structures are usually fabricated from plates and shells. Collision of this class of structures is usually modeled as plate and shell structures subjected to dynamic impact loading. The understanding of the dynamic response and energy transmission of the structures subjected to low velocity impact is useful for the efficient design of this type of structures. The transmissions of transient energy flow and dynamic transient response of these structures under low velocity impact are presented in the paper. The structural intensity approach is adopted to study the elastic transient dynamic characteristics of the plate structures under low velocity impact. The nine-node degenerated shell elements are adopted to model both the target and impactor in the dynamic impact response analysis. The structural intensity streamline representation is introduced to interpret energy flow paths for transient dynamic response of the structures. Numerical results, including contact force and transient energy flow vectors as well as structural intensity stream lines, demonstrate the efficiency of the present approach and attenuating impact effects on this type of structures.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
• /
• pp.228-230
• /
• 2008

The response time characteristic of low voltage liquid crystals (LCs) is investigated and a new simulator for low voltage LCs is proposed. In order to enable low voltage operation, it is important to minimize Vth of LCs and variation of pixel voltage caused by dynamic capacitance operation of LC Display. Because dynamic capacitance variation is much larger for low voltage LC operation compared to that of conventional LC material, it is necessary to make a better model for dynamic capacitance operation. A proposed minimizing Vth of LCs and variation of pixel voltage study results through a new constant charge model improve response characteristics for low voltage LCs operation.

• 전기전자학회논문지
• /
• 제23권2호
• /
• pp.552-556
• /
• 2019

본 논문에서는 전류 제어 회로를 이용하여 load Transient response 특성을 향상시킨 capless LDO(low drop-out) 레귤레이터를 제안하였다. LDO 레귤레이터 내부의 오차증폭기와 패스 트랜지스터 사이에 전류 조절 회로를 두어 전압 라인에 들어오는 전류특성을 개선시켜 기존의 LDO 레귤레이터보다 향상된 transient 응답특성을 갖는다. 제안된 회로는 cadence의 virtuoso, spectre 시뮬레이터를 이용하여 0.18 um 공정에서 특성을 분석하였다. 실험 결과에 따르면, 제안된 회로 구성을 이용한 LDO의 load transient response는 기존 LDO과 비교하여 부하 전류가 rising time인 경우 1.954 us에서 1.378 us, falling time인 경우 19.48 us에서 13.33 us으로 약 29%, 28% 개선된 응답속도를 가진다.

• Clinical and Experimental Reproductive Medicine
• /
• 제14권2호
• /
• pp.101-108
• /
• 1987

In order to evaluate the consistency of the serum estradiol pattern and response and to determine the influence of number of ovary on them in repeat cycles in the same patient, 57 cycles in 24 patients who underwent in Vitro Fertilization-Embryo Transfer or Gamete Intrafallopian Transfer in Seoul National University Hospital. The patients were stimulated by follicular stimulating hormone and human menopausal gonadotropin and classified as high(${\geqq}$400 pg/ml) and low(<400 pg/ml) response group according to preovulatory estradiol concentration and classified as three estradiol patterns (A,G.B) according to Jones criteria. Seventeen(89.5%) of 19 patients in when a high response to ovulation induction in their first cycle showed a high response. 40%(2/5) of the second ovulation induction cycle were low response in the patient whose first cycle resulted resulted in a low response. Serum estradiol pattern in the first ovulation induction cycle tended to be repeated in the second cycle. Women with high response tended to be more likely to have A and G patterns and less likely to have a cancellation than those with low response. One-ovary patients were at higher risk for inadequate ovulation induction response.