• Journal of the Korean Geophysical Society
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• v.5 no.2
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• pp.87-97
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• 2002

P wave travel-time delays have been analyzed and average travel-time anomalies due to lateral variation of the crustal structure have been calculated at the broad-band earthquake observatories of Korea Meteorology Administration (KMA) using the teleseismic deata collected during the period from 2000 to 2001. Maximum variation in the relative travel-time residuals is almost 1.5 seconds Azimuthal variation in the travel-time residuals is observed to indicate the existence of lateral P velocity heterogeneity beneath the stations with velocity contrasts of -4~4%. The estimated average travel-time delays are ranging from 0.05 to 0.3 seconds at the stations including Seoul, Chuncheon, Kanneung, Uljin, and Ulleung Island showing slow velocity contrasts of 0~4% P through the crust. Faster velocity contrasts of 0~4% have been observed at the stations including Seosan, Taejeon, Daegu, Seoguipo, and Busan showing average travel-time delays ranging from -0.05 to -0.3 seconds.

• Journal of the Daesoon Academy of Sciences
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• v.33
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• pp.179-218
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• 2019

This article examines some important issues in films about new religious movements (NRMs) that express and represent NRMs in sensationalistic ways and criticize them as immoral and antisocial cults. I presented a typology to analyze films about NRMs from the perspective of marginalized religions separated from established religions and also as alternative religions that replace the established religions. In recent times, films about NRMs have changed from being social criticisms that represents NRMs as perpetrators of brainwashing and the need for deprogramming to that of faithful participation and empathetic reflection. Films about NRMs that utilize empathetic reflection, including Wild Wild Country (2018), go beyond the normative, single-perspective formula to enable insiders to conduct self-reflection and outsiders to empathize through openness, varied perspectives with multi-faceted composition and polyphony. In contrast, films about NRMs that adopt the perspective of faithful participation, including The Road to Peace (1984), present a new visual way to unravel the voices of silenced subalterns with alternative religious visions and those who needed relief from the marginalization due to alienation or exclusion from established religions. In the Korean context, these visions are expressed as 'the great transformation into the creation of a paradise of the Later World (後天開闢)' or as 'the resolution of grievances for mutual beneficence (解冤相生).'

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.4
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• pp.334-341
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• 2003

When the pressure tubes(f are in contact with the calandria tube(CT) in the pressurized heavy water reactor(PHWR), the temperature difference between inner and outer wall of W results in a thermal diffusion of hydrogen (deuterium) and hydride blisters are formed on the outer surface of PT. Because the hydride blisters and zirconium matrix are acoustically continuous, it is not easy to distinguish the blisters from the matrix with conventional ultrasonic method. An ultrasonic velocity ratio method was developed to detect small hydride blisters on the zirconium pressure tube. Hydride blisters were grown in the PT specimen using a steady state thermal diffusion device. The flight times of longitudinal echo and reflected shear echo from the outer surface were measured accurately. The velocity ratio of the longitudinal wave to the shear wave was calculated and displayed using contour plot. Compared to the conventional flight time method of longitudinal wave, the velocity ratio method shows superior sensitivity to detect smaller blisters as well as better images for the blister shapes. Detectable limit of the outer shape of the hydride blisters was conservatively estimated as $500{\mu}m$, with the same specifications of ultrasonic transducer used in the actual PHWR pressure tube inspection.

• Journal of the Korean Geophysical Society
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• v.5 no.3
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• pp.165-174
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• 2002

Seismic velocity and attenuation coefficient of the rocks under the broad-band earthquake observatories of the Korea Meteorological Administration have been measured in the laboratory by using very high frequency seismic waves. Estimated P velocities of the rocks range from 3.2 km/s to 5.6 km/s, depending on the rock type, mineral, and weathering, while, the attenuation coefficients vary from 0.06 to 4.3 db/kHz-m. It seems that P velocities is inversely proportional to the attenuation coefficients of the rocks. Average travel-time delays of the broad-band stations seem to be related with the measured P velocities in the laboratory.

• The Journal of Engineering Geology
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• v.6 no.3
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• pp.137-153
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• 1996

The purpose of this study is to investigate the possibilities of identifying and detecting underground cavities using seismic waves recorded by the fixed and mobile stations. During 18 months of field work we recorded chemical explosions near the Bongdarn station. Seismic Stations were installed on the free surface and underground inside the Samba mine. The seismograms at the fixed(lorg-term) seismic station show abrupt change of polarization characteristics which can he associated with the appearance of P-to-S converted phase(PS) at 150 ~ 200 msec after the first P arrival. This result indicates that converted phases are generated very near to the Bongdarn station at a depth of 190m. Shear-wave splitting phenomena have also been observeci The time delay between fast shear(fS) and slow shear(sS) waves ranges between 30 and 60 msec(average is 42 msec). However, exact time delay between the fast and the slow shear waves can not be accurately measured because of the very short time delay and limitation of sampling rate. Chemical explosion experiments were recorded at stations along various paths to contrast the seismic response of areas with and without cavities. The seismograms recorded at the stations installed at cavity areas show an abrupt change of polarization characteristics but not on the other stations. Seismic waves propagating through the cavity are characterized by the attenuation of high frequency waves and predominantly low frequency seismic waves after the S wave arrivals.

• Geophysics and Geophysical Exploration
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• v.12 no.3
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• pp.225-232
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• 2009

As part of seismic experiments investigating crustal velocity structures of the Korean peninsula, permanent (fixed) seismographs of the Korea Meteorological Administration (KMA) network recorded seismic signals from four and eight large explosions in Korean Crustal Research Team (KCRT) profiles shot in 2004 and 2008, respectively. Among the seismograms recorded by 43 velocity sensors and 103 accelerometers at KMA stations distributed throughout the southern Korean Peninsula, 156 records with epicentral distances less than 120 km and high signal-to-noise ratios were analyzed to determine velocity anisotropy of the Pg phase. Relative elevation corrections of -101.6 to 105.3 ms were made using velocity information derived from the 2004 KCRT profile data and differences in elevation between the permanent KMA stations and the temporary stations in the KCRT profiles at the same source-receiver offsets. To remove site effects, receiver-station corrections of -89.6 to 192.2 ms were additionally made to the KMA station data by subtracting the average differences in traveltimes between KMA stations and portable stations at the same offsets for all available shots with different azimuths. With the exception of anomalously fast velocities along trends of the Chugaryeong fault zone and the Okchon fold belt and anomalously slow velocities in the regions of high terrestrial heat near Yeongduk and Ulsan, the analysis of crustal velocity anisotropy using the Pg phase indicates overall isotropy in the southern half of the Korean peninsula.

• Geophysics and Geophysical Exploration
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• v.16 no.1
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• pp.18-26
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• 2013

Shear-wave velocity ($v_s$) structures beneath two seismic stations, JJU and JJB on the flanks of the volcano Halla on Jeju island, Korea, were estimated by receiver-function inversion and H-${\kappa}$ stacking applied to 150 teleseismic events ($M_W{\geq}5.5$) recorded since 2007. $P_S$ waves converted at the Moho discontinuity does not appear clearly for northwesterly back-azimuths ($207{\sim}409^{\circ}$, average $308^{\circ}$) at station JJU and southeasterly back-azimuths ($119{\sim}207^{\circ}C$, average $163^{\circ}$) at station JJB. This may be due to a gradual velocity increase at Moho or heterogeneity within the crust. The $v_s$ models derived by inversion of receiver functions indicate a distinct low velocity layer ($v_s{\leq}3.5km/s$; LVL) within the crust and a gradual increase in $v_s$ in the depth interval of 30 to 40 km. Within the radius of 18 km beneath station JJB, the LVL occurs at depths of 14 ~ 26 km and the 'Moho' ($v_s{\geq}4.3km/s$) is at 34 km depth. Ten kilometers to the west, within the radius of 16 km beneath station JJU, both the LVL and the Moho are significantly shallower, at depths of 14 to 24 km and 30 km, respectively. H-${\kappa}$ analyses for stations JJU and JJB yield estimated crustal thickness of 29 and 33 km and $v_p/v_s$ ratios of 1.64 and 1.75, respectively. The lesser $v_p/v_s$ ratio was derived for rocks nearest to th peak of the volcano.

• Journal of Korean Philosophical Society
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• v.105
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• pp.291-320
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• 2008

이 글은 2004년 충남대학교 국사학과 한국학술진흥재단 기초학문지원 마을사연구의 공동연구 작업에 의한 연구 성과물이다. 연구 대상 마을인 충남 논산시 노성면 병사리는 17세기 호서지역의 3대거족의 하나인 파평윤씨노종오방파(坡平尹氏魯宗五房派)가 세거했던 마을이다. 이 마을의 대표적인 유학자로는 우암(尤庵) 송시열(宋時烈)과 40년 동문사이인 노서(魯西) 윤선거(尹宣擧)와 그의 아들인 명재(明齋) 윤증(尹拯)이 있고, 그 외 파평윤씨노종오방파의 유서와 전통을 이어갈 수 있도록 토대를 닦은 동토(童土) 윤순거(尹舜擧) 등이 있다. 그리고 이 글의 주제 인물인 둔옹(鈍翁) 윤지(尹指)는 동토(童土) 윤순거(尹舜擧)의 아들이다. 특히 윤지(尹指)는 동토(童土) 선생의 서자로 태어났지만 명재(明齋) 윤증(尹拯)의 뒤를 이어 노종오방파(魯宗五房派)의 종중서당(宗中書堂)인 종학당(宗學堂)의 사장(師長)을 지낸 인물이다. 적서의 차별이 엄연함에도 불구하고, 파평윤씨노종오방파(坡平尹氏魯宗五房派) 자제들의 교육을 총책임지는 막중한 소임을 맡았던 것이다. 그 결과 그가 사장(師長)으로 있는 동안 수많은 과거 급제자들을 배출하였을 뿐만 아니라 선대에 이루어 놓은 가학적 전통을 후세에 전할 수 있는 매개자 역할을 훌륭하게 수행했다. 그러나 그동안 윤지(尹指)의 사장(師長)으로서의 생애와 학문 활동에 대해서는 전연 알려지지 않은 채 베일에 가리어져 왔다. 그러던 중 그의 대표저서인 "둔옹집(鈍翁集)" 이 그의 사후 200 여년 이 지난 1916년에 8대 족손 윤구병(尹龜炳) 윤혜병(尹惠炳) 등에 의해 간행되었다. 이에 그의 학문이 세상에 알려질 수 있는 계기가 되었던 것이다. "둔옹집(鈍翁集)"은 "연소천지문답(演小天地問答")과 동몽문답(童蒙問答) 등 두 편으로 구성된 문집인데, "연소천지문답(演小天地問答)"은 4권 1책, 약 13만 여자 분량으로 그 주요 내용은 한의학과 관련된 내용이 주로 되어 있고, 동몽문답(童蒙問答)은 1권 1책 약 7,600여 자 분량으로 주역(周易)의 기본 구성원리인 음양오행설을 자문자답의 형식을 빌려 소개하고 있다. 이 글의 전반부는 둔옹(鈍翁) 윤지(尹指)의 생애를 소개한 후 중반부 이후부터 그의 음양오행에 대한 이해를 소개하였다. 그리고 파평윤씨노종파 3人(윤선거(尹宣擧) 윤증(尹拯) 윤지(尹指))의 주역 이해를 통해 그들의 가학의 일단을 엿보았다. 다만 이글은 둔옹(鈍翁) 윤지(尹指) 연구의 효시(嚆矢)로써 그의 철학의 구체적인 내용 보다는 그의 생애와 개략적인 학문 활동을 소개하는 것에 초점을 맞추었다. 차후 그의 철학의 핵심이 담겨져 있는 "연소천지문답(演小天地問答)"은 장차 한의학 분야 전공자와의 공동연구를 통해 소개해야 할 것이다.