• Journal of Astronomy and Space Sciences
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• 제18권3호
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• pp.191-208
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• 2001

We have recently compiled a database of the properties of 192 impact craters, which supercedes previous compilations. Using our database, the impact structures found in North America, Europe and Australia have been examined; these cratonic areas have been relatively stable for considerably long geological periods, and thus have been best preserved. It is confirmed that there is a close correlation between the geological epoch boundaries, the epochs of mass extinctions, antral the "timing" of impacts. In addition, the terrestrial cumulative flux of objects >20km is found to be $1.77{\times}10^{-15}km^{-2}yr^{-1}$, over the last 120 Myr, which is much smaller than the published values in McEwen et al. (1997) and Shoemaker (1998) ($5.6{\pm}2.8{\times}10^{-15}km^{-2}yr^{-1}$. For terrestrial impact structures with D> 50 km, the apparent cumulative flux over the last 2450 Myr is ~50 times smaller than the corresponding value for the Moon. If we assume that the Earth and the Moon suffered the same level of bombardment over this time, this would mean that the actual flux of impacting bodies, capable of making craters with D)50 km, was ~ 50 times larger than the apparent flux estimated from the currently known terrestrial records.

• Communications for Statistical Applications and Methods
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• 제25권2호
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• pp.131-157
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• 2018

We propose a robust event date model to estimate the date of a target event by a combination of individual dates obtained from archaeological artifacts assumed to be contemporaneous. These dates are affected by errors of different types: laboratory and calibration curve errors, irreducible errors related to contaminations, and taphonomic disturbances, hence the possible presence of outliers. Modeling based on a hierarchical Bayesian statistical approach provides a simple way to automatically penalize outlying data without having to remove them from the dataset. Prior information on individual irreducible errors is introduced using a uniform shrinkage density with minimal assumptions about Bayesian parameters. We show that the event date model is more robust than models implemented in BCal or OxCal, although it generally yields less precise credibility intervals. The model is extended in the case of stratigraphic sequences that involve several events with temporal order constraints (relative dating), or with duration, hiatus constraints. Calculations are based on Markov chain Monte Carlo (MCMC) numerical techniques and can be performed using ChronoModel software which is freeware, open source and cross-platform. Features of the software are presented in Vibet et al. (ChronoModel v1.5 user's manual, 2016). We finally compare our prior on event dates implemented in the ChronoModel with the prior in BCal and OxCal which involves supplementary parameters defined as boundaries to phases or sequences.

• 한국주거학회논문집
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• 제26권6호
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• pp.139-146
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• 2015

In this study, the plane type of main building relics of unified Silla period house site which excavated in Gyeongju city after 1990s was classified and the architectural characteristic of them was investigated. The chronology of building relics in Silla capital city site was mostly known as 8-9th century, and by standard of column arrangement, the plane types of them could be classified as grid type, front veranda-grid type, outer column type. The outstanding characteristic of plane is wide span and open front veranda. In most relics the span were over 4 meters, and inner foundations for small post and strip foundation were found between columns. The front veranda added type buildings were composited of enclosed main room and open front veranda, and column arrangement of them dose not fall into line in most case. Thus it thought that the structures of enclosed main room and open front veranda were independent. The interior space of enclosed main room were divided two rooms by partition wall in some case. In this case, one room is enclosed by wall, and the other room has open front side. This plane is considered for the pleasant life in cold winter and hot summer.

• Korea-Australia Rheology Journal
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• 제11권4호
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• pp.279-285
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• 1999

Draw resonance is both an important and interesting instability encountered in various extensional-deformation-dominated polymer processing operations. It is important because of its paramount relevance to the productivity and quality issue in the related industry: and it is interesting because of as yet unanswered questions as to what its cause and origin are in terms of physics involved. Specifically, a short chronological account of the draw resonance research is presented in this paper bringing several previous results together and focusing on the derivation of a new criterion for draw resonance based on the interaction of the traveling times of some kinematic waves propagating along the spinline from the die exit to the take-up position. The new explanation of draw resonance put forward here based on the physics of the system is seen to have wide implications on both theoretical and practical aspects of draw resonance instability. The importance of the role played by spinline tension in determining draw resonance is an example of the former whereas interpretation of the mechanism of the draw resonance eliminator is an example of the latter. Finally, an approximate yet a very fast and convenient method for determining draw resonance is also derived based on the above findings and found to agree well with the exact stability results.

• 한국산림과학회지
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• 제84권1호
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• pp.71-76
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• 1995

본 연구는 강원도에 분포하는 소나무를 대상으로 지리적(地理的) 요인(要因)에 의한 소나무 생장권역(生長圈域)을 구분하는데 목적이 있다. 기초자료로는 생장추로 채취한 공시목편의 직경 연년생장량(連年生長量)의 실측치를 이용하였다. 실측된 연년생장량내의 개체간 변이를 표준화(標準化) 과정을 통해 제거하였고 표준화된 값으로 지역별 평균연대기(平均年代期)를 산출하였다. 지역별 평균연대기들을 집락분석(集落分析)하여 직경의 연년생장 패턴에 따라 생장지역을 구분하였다. 분석결과 영동과 영서지방 소나무의 연년생장 패턴이 지리적 분포와 유사한 경향을 보였다. 또한 영서내륙지방은 지리적 요인에 따른 생장패턴의 변이가 큰 것으로 나타났다.

• 한국제4기학회지
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• 제16권1호
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• pp.29-36
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• 2002

설악산 서사면에 자라는 소나무 24본을 이용하여 317년(A.D.1682~A.D.1998)간의 5월 강수량을 복원하였다. 과거 317년 중 1690~1710년, 1745~1755년, 1847~1853년 기간이 5월 강수량이 적었던 것으로 나타났으며, 1715~1733년, 1835~1845년 기간은 다우기로 나타났다. 이중 1835~1845년 기간은 중부 내륙 연륜기후 복원자료에서도 다우기로 나타났던 기간으로 이 기간의 다우현상은 우리나라에서 광범위하게 발생되었음을 알 수 있었ㄷ. 100년 단위별 강수량 비교에서 20세기 5월 강수량이 18세기,19세기와 차이가 없었다. 전 기간에 걸친 5월 강수량 주기는 2~4년으로 장주기보다 단주기 변화가 잘 나타났다.

• 한국제4기학회지
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• 제15권1호
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• pp.47-52
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• 2001

설악산 백담산장 (해발고 400m) 지역에서 자라는 소나무를 이용하여 141년 (A.D. 1858∼1998)간의 나무나이테(연륜) 연대기를 작성하여 4월∼8월 총강수량을 복원하였다. 복원한 결과 1880∼1887년, 1893∼1901년, 1922∼1938년은 건조기로 나타났으며, 1906∼1918년은 습윤기로 나타났다. 장기간 변동으로 보았을 때, 19세기말과 20세기초는 20세기 후반기보다 건조하였다. 전기간에 걸친 가뭄주기는 4.14년과 3.16년으로 분석되어 장주기보다 단주기 변화가 우세하였다.

• 한국문헌정보학회지
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• 제33권3호
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• pp.63-86
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• 1999

본고는 소장데이터용 MARC 포맷의 일반적 특성과 개발현황에 대해 살펴보고, 아울러 MARC 포맷의 3요소로 일컬어지는 구조와, 내용표지법, 레코드의 내용을 이미 개발된 USMARC과 KORMARC 포맷을 중심으로 분석하였다. 레코드의 구조와 내용표지법은 서지용 및 전거용포맷과 대부분 동일하다. 데이터필드는 기본적으로 기능별블록으로 구분되어 있으나, 현재는 0XX, 5XX, 8XX 필드만이 사용되고 있다. 008 필드의 레코드 내용에는 수서와 보유정책 등 자료의 소장에 관련된 요소들이 추가되어 있다. 가변길이필드의 내용은 번호와 코드, 주기, 소재와 접근, 소장데이터 필드 등으로 구성되며, 특히 소장데이터필드는 다시 캡션과 패턴, 권호와 연대, 문장형식소장정보 자료정보 등의 필드로 구성된다. 본고에서는 각 필드별로 그 내용을 구체적으로 분석하고 있다.

• 한국안전학회지
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• 제28권1호
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• pp.137-143
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• 2013

Cultural heritage passing down to posterity is a global concern. But there are many culture heritage that not remained to now disappeared by various disasters. It is told that disaster is learnt from disaster. The most fundamental task in disaster prevention is to collect and analyze cases of accidents so as not to repeat a disaster. In other words, an analysis of various disaster-related materials and their countermeasures in the Joseon period is an actual condition-based phenomenological methodology used to prevent disasters at cultural properties today. In this context, it is important to collect histories of disasters in the Joseon period, to extract disaster-related historical data and to categorize the data to build a disaster literature database. This study has produced [Database of Disasters in the Joseon Era], a collection of articles on fire outbreaks based on The Annals and The Daily Records belonging to the Memory of the World. On the basis of this chronology, human and property damages caused by fires in Joseon have been examined, identified by districts, as well as disaster technologies, have been analyzed. It has also built disaster vulnerability maps in the Joseon Dynasty Era.

• 한국환경복원기술학회지
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• 제14권2호
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• pp.1-10
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• 2011

Six pine trees (Pinus densiflora S. et Z.) at the Euilimji Lake Park in Jecheon were collected to investigate tree ages, growth decline pattern and the years of death. Tree-ring measurement was carried out using the Lintab with a resolution of 0.01mm. Tree age were 80-176 years. Cross-dating between the tree-ring series of each tree and the local chronology from Worak Mountain resulted that four and two trees died in 1998 and 1999, respectively. Three dead trees had only formed earlywood in the outermost tree ring and the others had incomplete latewood. Therefore, it was proven that the former trees died between spring and early summer, whereas the later ones died during late summer and/or autumn. The simultaneous deaths of trees suggest the insect damage and/or drought may be the crucial reason of the death, but frequent reaction woods, which were formed by leaning stem, and scars formed by physical damage may also contribute to the death.