• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.421-435
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• 1998

An empirical formula for estimating duration magnitude(MD)is determined by analyzing 619 epicentral distance-duration data set, obtained from earthquakes of 1989-1998 recorded at the KMA network. Based on two assumptions: 1) observed signal duration decreases with increasing epicentral distance, and 2) seismographs of KMA are set at low-gain and therefore inclusion of sensitivity correction term in the equation is not necessary, scaling predicted duration at epicenter to Tsuboi's local magnitude yielded the duration magnitude equation: MD =2.0292$\times$log$\tau$＋0.00123Δ-1.4017 for 1/0$\leq$ML$\leq$5.0, where $\tau$is total signal duration(sec)and Δis epicentral distance(km). Event by event comparison of ML values against MD estimates for t152 events shows that for events having a same ML the difference in MD estimates reaches as high as 1.1 magnitude units. So, to test the usefulness of the duration magnitude equation, we have calculated ML-MD relations by which duration magnitude estimates are converted to local magnitudes ("predicted" ML, say) which are then compared with the directly determined local magnitude values. Except for events with stations where duration is anomalously reestimates(predicted ML) which are in an agreement within a 0.2 magnitude units with the corresponding ML values. Although this study could gain some insights into magnitudes of the past events, we still need to re-examine all the observables in order to obtain more reliable and precise information about magnitude and hypocenter location. So we will pursue a new local-magnitude scaling, as well as refinement of the duration magnitude equation, starting soon with re-reading the amplitudes-arrival time records of (and hence relocating) 250+earthquakes of 1979-present recorded at the KMA network. Thus, with more reliable and precise earthquake parameters determined we would better understand the recent seismicity and related tectonic process within and adjacent region to the Korean peninsula.peninsula.

• 아동학회지
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• 제38권1호
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• pp.117-126
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• 2017

Objective: The purpose of this study was to investigate young children's nonsymbolic magnitude comparison ability according to ratio limit and task condition. Methods: The participants included 40 3-year-old children, 42 4-year-old children, and 41 5-year-old children recruited from 4 childcare centers located in Seoul, Korea. All magnitude comparison tasks were composed of image material tasks and concrete material tasks. In addition, each magnitude comparison task varied with the ratio of the two quantities; 0.5 ratio, 0.67 ratio, 0.75 ratio. Results and Conclusion: The results revealed that 3-, 4-, and 5-year-old children could perform nonsymbolic magnitude comparison tasks without learning experiences. Also, 3-, 4-, and 5-year-old children could perform concrete material tasks better than image material tasks in nonsymbolic magnitude comparison tasks. Furthermore, children's performance on nonsymbolic magnitude comparison tasks indicated the ratio signature of the approximate number system. Children have a degree of numerical capacity prior to formal mathematics instruction. Also, children were influenced by task conditions or sense stimulus when they processed numerical information. Furthermore, the approximate number system can be used in understanding the ordinality of number.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1997년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Fall 1997
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• pp.94-97
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• 1997

The December 13, 1996 Yeongweol earthquake of magnitude 4.5 was felt almost everywhere in southern part of the Korean Peninsula and Cheju Island, even though not feld in Tsushima Island at other places in Japan near to Korea. Production lines of semiconductor disk in electronic engineering companies of Gumi manufacturing complex were seriously affected by the shake of this earthquake. Total 17 earthquakes of magnitude 4 or above occurred within the area of 50km radius from Yeongweol in the period from the year 1400 to 1996. This group of earthquakes includes 12 events of magnitude 5.0 or above and 3 events of magnitude 6.0 or above. Among these events, 13 earthquakes are historical events of years 1400-1904. Most of them occurred in 15-16 centuries. The February 21, 1596 Jungseon-Pyeongchang event of magnitude 6.5 is the largest one up to now in the area. There are four instrumental earthquakes (years 1905-1996) of magnitude 4.0 or above in this area. An earthquake of magnitude 4.4 occurred on 5th of November, 1919 at almost the same place as the December 13, 1996 earthquake of magnitude 4.5. Thus this event is preceded with the previous one by 77 years.

• 한국멀티미디어학회논문지
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• 제10권6호
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• pp.737-744
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• 2007

This paper proposes the blind watermarking algorithm for digital video based on magnitude modulus subband in wavelet transform domain. After transforming each of frames into wavelet domain, the proposed algorithm divides LH, HL, and HH subbands of 2-level into $3{\times}3$ blocks and calculates average magnitude modulus of all blocks. Then the watermark bit is embedded into a target magnitude modulus comparing with an average magnitude modulus within a block. Experimental results were confirmed that the proposed algorithm has the good robustness against MPEG and frame attacks than the conventional algorithm.

• 한국정보전자통신기술학회논문지
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• 제9권4호
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• pp.414-418
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• 2016

본 논문은 저면적 gradient magnitude 연산을 위한 하드웨어 구조를 제안한다. 하드웨어 복잡도를 줄이기 위해 정사영 벡터의 특징 및 하드웨어 자원 공유기법을 이용했다. 제안된 하드웨어 구조는 gradient magnitude 연산 알고리즘의 변형 없이 구현되었기 때문에 gradient magnitude 데이터 품질의 열화 없이 구현될 수 있다. 제안된 저면적 gradient magnitude 연산 하드웨어는 Altera Quartus II v15.0 환경에서 Altera Cyclone VI (EP4CE115F29C7N) FPGA를 이용하여 구현되었다. 구현 결과, 기존 하드웨어 구조를 이용하여 구현한 연산기와의 비교에서 15%의 logic elements 및 38%의 embedded multiplier 절감 효과가 있음을 확인했다.

• 한국지진공학회논문집
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• 제18권1호
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• pp.29-36
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• 2014

In industrial facilities sites, the conventional method determining the earthquake magnitude (M) using earthquake ground-motion records is generally not applicable due to the poor quality of data. Therefore, a new methodology is proposed for determining the earthquake magnitude in real-time based on the amplitude measures of the ground-motion acceleration mostly from S-wave packets with the higher signal-to-ratios, given the Vs30 of the site. The amplitude measures include the bracketed cumulative parameters and peak ground acceleration (As). The cumulative parameter is either CAV (Cumulative Absolute Velocity) with 100 SPS (sampling per second) or BSPGA (Bracketed Summation of the PGAs) with 1 SPS. The arithmetic equations to determine the earthquake magnitude are derived from the CAV(BSPGA)-As-M relations. For the application to broad ranges of earthquake magnitude and distance, the multiple relations of CAV(BSPGA)-As-M are derived based on worldwide earthquake records and successfully used to determine the earthquake magnitude with a standard deviation of ${\pm}0.6M$.

• 한국자동차공학회논문집
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• 제15권6호
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• pp.108-113
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• 2007

This study aims to find equivalent comfort contours, reciprocal of frequency weighting curves, for vertical steering wheel vibration. Psychophysical responses were measured from twelve male subjects by using magnitude estimation of relative discomfort due to vertical steering wheel vibrations of magnitude of 0.1 to 1.58 $m/s^2$ in the frequency range of 4 to 250 Hz. Relative discomfort were estimated with a reference vibration of 0.4 $m/s^2$ at 31.5 Hz. Equivalent comfort contours were produced from the median of sensation magnitudes judged by twelve subjects, which showed variation in the shapes with increase of vibration magnitude. A shape of the contour came close to the perception threshold curve with decrease of vibration magnitude. When the vibration magnitude increases, the shape changed close to those in the references of Hong and et al (2003). It is also recommended frequency weighting curves for vertical steering wheel vibration must be expressed as a function of vibration magnitude as well as frequency.

• Earthquakes and Structures
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• 제25권5호
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• pp.325-342
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• 2023

The damping modification factor (DMF) is used to modify the 5%-damped response spectrum to produce spectral values that correspond to other necessary damping ratios for seismic design. The DMF has been the subject of numerous studies, and it has been discovered that seismological parameters like magnitude and distance can have an impact on it. However, DMF formulations incorporating these seismological parameters cannot be directly applied to seismic design because these parameters are not specified in the present seismic codes. The goal of this study is to develop a formulation for the DMF that can be directly applied in seismic design and that takes the effects of magnitude, distance, and site conditions into account. To achieve this goal, 16660 ground motions with magnitudes ranging from 4 to 9 and epicentral distances ranging from 10 to 200 km are used to systematically study the effects of magnitude, distance, and site conditions on the DMF. Furthermore, according to the knowledge that magnitude and distance affect the DMF primarily by changing the spectral shape, a spectral shape factor is adopted to reflect influences of magnitude and distance, and a new formulation for the DMF incorporating the spectral shape factor is developed. In comparison to the current formulations, the proposed formulation provides a more accurate prediction of the DMF and can be employed directly in seismic design.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1995년도 추계학술대회논문집
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• pp.13-17
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• 1995

A Psychophysical scaling method called magnitude estimation is frequently used to evaluate human sensation to physical stimuli. This paper described the procedure of magnitude estimation data analysis which consists of four modulus; reponse space, CMM(Cross-Modality Matdhing)/merge, standardization, scale building & data analysis method. This procedure is being developed as an expert system in which the four analysis modulus are programmed so that a novice user can perform the analysis.

• 지구물리
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• 제4권1호
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• pp.47-55
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• 2001

한반도를 중심으로 32～44°N, 123～133°E 사이에서 발생한 지진 중 M_0와 함께 m_b 또는 M_s가 결정된 50개의 계기지진을 이용하여 실체파(m_b), 표면파(M_b), 또는 둘 다로부터 지진 모멘트(M_0)를 계산하는 환산식을 개발하였다. 진원깊이 70km 이상은 심발지진으로, 이하는 천발지진으로 분류하였으며, M_0의 단위는 dyne-cm이다. 표면파규모의 경우 심발지진이 천발지진보다 큰 지진모멘트를 갖는 것으로 나타났다. 심발지진과 천발지진 환산식에 수반된 표준편차는 모멘트 규모로 각각 0.25과 0.16이며 그 관계식은 각각 다음과 같다. (심발지진) (천발지진) 실체파규모의 경우 환산식은 진원깊이에 크게 영향을 받지 않는 것으로 나타났다. 환산식에 수반된 표준편차는 모멘트 규모로 0.28이며 그 관계식은 다음과 같다. 실체파와 표면파가 동시에 결정된 경우 새로운 규모 을 정의하여 별도의 환산식을 구했다. 천발지진만이 분석에 이용되었으며, 환산식에 수반된 표준편차는 모멘트 규모로 0.14이고 그 관계식은 다음과 같다. 이상의 분석결과는 한반도 및 인근 지역의 지진 크기를 하나의 지진규모, 즉 모멘트 규모로 통일하는데 이용될 수 있다.