• Journal of The Geomorphological Association of Korea
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• v.20 no.4
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• pp.117-131
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• 2013

2010 eruption of Eyjafjallajokull volcano in Iceland and 2011 Shinmoedake's eruption in Japan evoked concerns from researchers for the possibility of explosion of Baekdusan volcano after long dormancy (repose period). National Emergency Management Administration has tried to evaluate the vulnerability of volcanic disaster and to prepare response to the potential risk and to mitigate the damages from the volcanic eruption, but a few studies have focused on the activities of Baekdusan. This study aims to clarify what the criteria between dormant volcano and active volcano based on geomorphologists' and geologists' researches. Volcanic experts have made a criterion of activeness such as the evidence of volcanic eruption within 10,000 year before present. More rigorous criterion which was made in 1991 by Japanese Meteorological Administration was 2000 years B.P. Both Baekdusan and Hallasan satisfy two criteria, so it is necessary for us to monitor the activity of both volcanoes and to reflect the facts into the curriculum.

• Journal of The Geomorphological Association of Korea
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• v.24 no.2
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• pp.65-78
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• 2017

In this study, stable carbon isotopic analysis (22 specimens) and magnetic susceptibility analysis (23 specimens) were conducted out on the specimens collected from two points (trench DT1, DT2) in the floodplain of Jemincheon(hereinafter the Jemin plain) to reconstruct the Holocene Environments (Period I, Period II, Period III) of the Jemin plain in Gongju, Chungnam. The results were as follows: In Period I (approximately 7,480~4,940 yrs B.P.) and especially around 7,480~7,320 yrs B.P., it was cool-dry and there were two minor climate fluctuations. This period received a continuous flow of sediments, rather than massive amounts of sediments due to abrupt flooding, and therefore, there was almost no soilization process. Period II(approximately 4,940~2,600 yrs B.P.) was also relatively cool-dry. However, in Period II b, unlike I, the minor climate fluctuations were less pronounced. In this period, flooding and desiccation repeated, inducing soilization processes especially around 3,160 yrs B.P. In Stage III (~360 yrs B.P.), it was warm and humid compared to II b. However, in III a, there was no inflow of sediments due to irregular flooding, and in fact, soilization process was more manifested than during II b due to the impact of the desiccation environment. However, there were some mass movements from Bonghwang Mt. (a.s.l. 147m) caused by heavy rains and typhoon during III b (approximately 360 yrs B.P.), thus moving a large amount of debris (i.e. gravel), which resulted in sedimentation.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.359-360
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• 2011

본 논문에서는 고속으로 디지털 홀로그램을 생성할 수 있는 하드웨어구조를 제안하였다. 수정된 컴퓨터 생성 홀로그램(computer-generated hologram, CGH) 알고리즘을 이용하고, 전체 화소에서 홀로그램의 한 화소씩 연산하는 방법을 선택하여 홀로그램 한 화소씩 계산하고 바로 출력 하여 메모리 병목현상을 제거하기 위한 파이프라인 기반의 하드웨어 구조를 제안하였다. CGH 알고리즘을 바탕으로 입력부, 연산부, 및 정규화부로 구성된 디지털 홀로그램 생성기의 구조를 제안하였고, 객체의 화소만 저장하여 반복 사용하기 때문에 메모리의 사용량을 줄일 수 있었다. 제안한 하드웨어는 세로 방향으로 확장을 하여 동작을 병렬화시킬 수 있다. 제안한 하드웨어는 1K의 광원에 대해 HD급 홀로그램을 초당 약 87장을 생성할 수 있었다.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.4
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• pp.383-389
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• 1999

The foraminiferal researches carried out on the bottom sediments of the Korean Yellow Sea were reviewed. They began from the materials collected in the mid-1960. Most of the study materials were obtained from the gravity or piston corers as well as from the grab samplers. However, relatively long cores were obtained by a drilling ship in the mid-1990. The paleoenvironmental and sea-level histories associated with the foraminiferal changes were the main topics of the foraminiferal researches. Micropaleontological characteristics were also revealed. Sediments were supplied through the input of the rivers and streams from the adjacent mainland China and Korean Peninsula since the Holocene. Although the open sea has influenced off Mokpo now, it had influenced off Kunsan in mid-Holocene which was clearly seen from the occurrence of planktonic foraminifera. However, more advanced methods of study adopting geochemistry such as an absolute age estimate, an isotope analysis and an analysis of elements in combination with other fields of studies related with foraminiferal ecology should be applied to foraminiferal researches to reveal marine geological phenomena, such as climatic fluctuations and related marine environmental changes, in more detail. Additionally, it should be kept in mind that paleontolgical research including foraminifera is essential to the understanding of the recent as well as ancient environmental changes of the earth.

• Proceedings of the Korean Quaternary Association Conference
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• 2007.06a
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• pp.6-6
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• 2007

• Journal of the Mineralogical Society of Korea
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• v.8 no.1
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• pp.23-28
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• 1995

그레자이트가 한국에서는 최초로 남동 황해 대륙붕의 준표층 니질퇴적물에서 발견되었다. 이 지역의 수심은 70~80m이며, 표층 퇴적물은 수십cm 두께의 사질과 니질퇴적물이 교호하는 것으로 보아 조류의 영향을 받은 홀로세의 해침에 의하여 형성된 것으로 보인다. 그레자이트 입자는 0.1~2mm의 크기에 구상의 형태로 산출되며 니질퇴적물 내에 산점상으로 산포되어 있거나 0.5cm 정도의 엽리를 형성하고 있다. 이 광물은 강한 자성을 가지고 있으며 육안으로는 검은색을 띄나, 반사현미경하에서는 황백색을 띠며 등방성을 보인다. 그레자이트의 화학조성은 Fe=54.36, S=42.37, As=0.14, Si=2.25 wt.%로서 S=4일 때의 화학식은 Fe2.95S4이다. X-선 회절분석에 의한 단위포의 크기는=9.8635$\AA$, V=959.6$\AA$3이며 밀도는 4.094 gm/cc이다. 이 광물은 산출상태, 조직적 특징 및 수반광물의 종류로 보아 생물의 활동에 의한 환원조건의 니질퇴적물 내에서 자생한 것으로 추정된다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.315-318
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• 2002

낙동강 삼각주의 분포하는 제4기 홀로세 퇴적층 중 북부와 중부, 그리고 남부지역에 해당하는 가덕도 (신항만 조성지역), 범방리 (경마장 조성지역), 양산 (신도시 조성지역)의 조간대 퇴적층에 대한 대자율 연구를 수행하였다. 퇴적층의 층위별 대자율은 입도와 관입저항에 비례하여 대자율도 증가한다. 가덕도의 70여m의 퇴적층 중 20m, 40m의 점토층에서 대자율 변화가 나타나는데 인접한 녹산지역의 연구견과와 비교하면 고환경이 변화되는 지점과 일치한다. 삼각주의 중부에 위치하는 범방리 점토시료는 기반암까지 층위별 대자율이 일정하며, 북부의 양산지역 점토시료는 하부로 갈수록 대자율이 증가하는데 이러한 결과는 시료의 입도 분포와 같은 양상이다. 가덕도 시료와는 달리 모든 점토층이 유사한 대자율을 보여주고 있어 퇴적 동안 환경의 변화는 인지되지 않는다. 이 지역의 시료가 가덕도에 비해 높은 고도에 위치하여 가덕도 시료의 상부 점토에 해당되는 것도 환경변화가 나타나지 않는 이유가 될 수 있다. 따라서 보다 광범위한 지역에 대한 연구가 요구 된다.

• Journal of the Korean Geographical Society
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• v.33 no.2
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• pp.127-142
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• 1998

Unsan alluvial plain is the backmarsh of Seomseokcheon which is a river originated from Chilseongdae(954m) on Mts Taeback, flowing into Donghae in southern Kangreung City, Kangwon Province. The vegetation change, geomorphic develoopment and depositional environment during the late Holocene have been investigated, using the methods such as boring, pollen analysis and radiocarbon dating. Because the deposits fo the study area are mainly consisted of peat and paety sand, they contained many pollen fossils. The peat layer has been sedimented since the high sea-level periods, 3,200 y. BP, and the records of vegetation change until now has well preserved here. According to archeological researches and the results of pollen analysis in east coast of Korea, it is supposed that the prehistoric rice farming in this area has begun since ca. 1,800 y. BP.

• Journal of the Korean Geographical Society
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• v.33 no.2
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• pp.143-163
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• 1998

In order to clarify the depositional environment and sea-level change at Ilsan area including Gawaji and Saemal valley plains, which is located at the right side in downstream of the Han River, boring data, radiocabon dating and diatom analysis were comprehensively investigated. As a result, the palaeogeographies fo this area altered by the transgressions and regressions after 7,000 y. BP could be restored. The high tide sea-level(mean high water level of spring tide) was arrived ca. 7,000y. BP at the valley plain and risen to ca. 5.5m at ca. 5000y. BP. Since then, the sea-level was kept up the same level to ca. 3,200 BP. The descended sea-level to ca. 2,300 BP was risen up to ca. 5.8m in ca. 1,800 y. BP. It is presumed that such a sea-level change as well as the different sediments in quantity supplied from the river basin of the valley plain could be effected to change diversely the depositional environment of the study area and eventually to the prehistoric human life.

• Journal of The Geomorphological Association of Korea
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• v.23 no.3
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• pp.1-11
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• 2016

This study estimated vegetation environment and agricultural activity during the late Holocene inferred from pollen analysis of peat on floodplain of Wangpo-cheon around Neungsan-ri, Buyeo-gun, South Korea. By result of pollen analysis of 28 horizons from Trench NS 1 and NS 4, vegetation environment during 2,300 to 1,700 yr BP was divided into Pollen Zone I (Quercus-Alnus), Pollen Zone II (Quercus-Alnus-Gramineae) and Pollen Zone III (Pinus-NAP-Gramineae). The pollen analysis suggests that agricultural activity in the Buyeo area was widely spread from the early time of the Pre-Iron Age to the late Samhan Age and buckwheat field seem to be built to substitute paddy field during the early time of the Pre-Iron Age.