• Title/Summary/Keyword: Cave

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Lunar Pit Craters Presumed to be the Entrances of Lava Caves by Analogy to the Earth Lava Tube Pits

  • Hong, Ik-Seon;Yi, Yu;Kim, Eojin
    • Journal of Astronomy and Space Sciences
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    • v.31 no.2
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    • pp.131-140
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    • 2014
  • Lava caves could be useful as outposts for the human exploration of the Moon. Lava caves or lava tubes are formed when the external surface of the lava flows cools more quickly to make a hardened crust over subsurface lava flows. The lava flow eventually ceases and drains out of the tube, leaving an empty space. The frail part of the ceiling of lava tube could collapse to expose the entrance to the lava tubes which is called a pit crater. Several pit craters with the diameter of around 100 meters have been found by analyzing the data of SELENE and LRO lunar missions. It is hard to use these pit craters for outposts since these are too large in scale. In this study, small scale pit craters which are fit for outposts have been investigated using the NAC image data of LROC. Several topographic patterns which are believed to be lunar caves have been found and the similar pit craters of the Earth were compared and analyzed to identify caves. For this analysis, the image data of satellites and aerial photographs are collected and classified to construct a database. Several pit craters analogous to lunar pit craters were derived and a morphological pit crater model was generated using the 3D printer based on this database.

Surgery for a Case of Three-Compartment Trigeminal Schwannoma : Technical Aspects

  • Chung, Jong-Chul;Chung, Seung-Young;Kim, Seong-Min;Park, Moon-Sun
    • Journal of Korean Neurosurgical Society
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    • v.48 no.4
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    • pp.383-387
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    • 2010
  • Complete removal of three-compartment trigeminal schwannomas is a challenge to neurosurgeons. To expand exposure of each compartment, the combination and modification of skull base approaches are necessary. The 61-year-old woman was admitted with chronic headache. Preoperative magnetic resonance imaging showed $47{\times}50{\times}40\;mm$-sized tumor originating primarily in the middle cranial fossa extended to the posterior and the infratemporal fossa. We performed operation in five stage; 1. Zygomatic osteotomy, 2. Inferior temporal fossa plate removal and foramen ovale opening, 3. Cavernous sinus opening, 4. Tailored anterior petrosectomy, 5. Meckel's cave opening. Combination of skull base surgery should be concerned according to the patient. In this study, extradural basal extension with zygomatic osteotomy, interdural posterior extension with tailored anterior petrosectomy, and intracavemous exploration are reasonable options for remodeling three-compartment lesion into a single compartment. Tailoring of bone resection and exploring through natural pathway between meningeal layers accomplish single-stage operation for complete removal of tumors.

A Process Study on the Cave Deposits: Speleothems (동굴(洞窟) 퇴적물(堆積物)의 형성과정(形成過程)에 관한 연구(硏究))

  • Oh, Jong-Woo
    • Journal of the Speleological Society of Korea
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    • no.89
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    • pp.46-58
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    • 2008
  • 동굴 퇴적물의 형성과정은 1단계 기권 (Atmosphere): 빗방울 (H2O) 이 대기중에서 CO2의 혼합으로 산성비 (H2CO2)가 되어 석회암 (CaCO3)에 떨어져서 최초의 용식작용이 시작된다. 2단계 토양권 (Pedosphere): 산성비와 석회암성분이 합쳐 형성된 가용성 화합물 (Ca(HCO3)2)은 식생부식(植生腐植)에 의한 토양 (Humic acidic soils) 에 의해 기반암의 용식이 촉진 되어 지표에는 Karren과 석문 (석문(石門) Natural Bridge), 와지 (Dolines, Sinkholes) 지형을 형성시키고, 암석의 분순물은 지표에 남겨져서 결국 적색풍화토 (Residuum, Risidual Redish Soils) 를 만든다. 3단계 암권 (Lithosphere): 용식작용에 의해 지상에서 지하 로 확대되어진 모암의 균열을 타고, 지하의 공간이 지하수의 유입과 유출에 의해 점차 확대되어 동공형의 Conduites; Voids; Shaft 이라는 특수지형을 형성시키고,동굴의 천정으로부터 나온 Ca(HCO3)2 는 탄산염의 지속적인 분해 공급에 의해 동굴내에는 종류석, 석순, 유착석 (Speleothem)등의 새로운 동굴지형 (Speleoscape)을 조성하게 된다. 4단계 수권 (Hydrosphere): 동굴의 형성작용을 거친 물은 동굴지하수로 잔여 Calcite를 함유한 채로 유출 (Spring) 된다. 동굴을 떠난 잔여 Calcite는 또다시 하천유역에 침전시켜서 석회화 단구형의 집적지형 (Tufa Formation: Tufa Dam, Tufa Flowstone)을 최종적으로 동굴을 나와 외벽 이나 하천의 바닦에 형성하는 과정을 거치면서 카르스트 지형의 발달과정이 1차적인 순환을 마치게 된다.

Caving Disaster and Oil Spill Removal Adsorbent Mag-Sorbent

  • Soh, Dea-Wha;Soh, Hyun-Jin;Soh, Hyun-Jun;Soh, Hyun-Jae
    • Journal of the Speleological Society of Korea
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    • no.85
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    • pp.28-34
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    • 2008
  • For trying to frontal attack of new solution by fusion of technical tasks and conditions with it's solving methods of the essential tasks of marine resource development and environmental conservation in addition with elements of electronic high-technologies, the magnetic oil spill adsorbent of Mag-Sorbent* has been prepared and proposed to dispose oil spill from the marine disaster for preventing oil pollution by using them and their system with sequentially circular collection of oil spill mag-sorbent powder and fabrics on the electronic equipment like as barge robot for the scheme of sustainable development of environment-friendly technology. Because of recent marine accident occurred at Tae-An cost and earthquake in Sichuan province were very large scale accident of disaster to prevent and manage of them. So, it was verified from the experiment of electronic demonstrator that the skimmer system of oil spill mag-sorbent powder and fabrics prepared was very effective and useful technique to collect oil spill samples on the water surface specially at the closed space of underground cave. At this point, the barge-based electronic remote control was very useful system operating easily on the marine fields but also water level at the small pool to skim it with the environment-friendly system of the disposing marine disaster and preventing oil pollution using magnetic adsorbents of Mag-Sorbent*.

Submarine Behavior Simulation based on 4-DOF Motion Platform and Stereoscopic Multi-Channel Visualization (4자유도 모션 플랫폼을 이용한 잠수함의 운동감 재현과 스테레오 다채널 가시화)

  • Xu, Zhenshun;Han, Soon-Hung
    • Korean Journal of Computational Design and Engineering
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    • v.17 no.5
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    • pp.333-341
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    • 2012
  • Modeling and simulation is important for military training. People can feel perspective when stereoscope images are created using multi-channel visualizations. A submarine oscillates when the submarine is just below the surface of the sea, so that the reconnaissance becomes difficult. Also, the operator should read the information of the target within 6 seconds using the periscope. The operator must have experience. To solve these problems, stereoscopic multi-channel visualization has been tested. The iCAVE system of KAIST provides a large-scale screen, 7 PCs, and 14 projectors to create the stereoscope images. To simulate the motion of a submarine just below the ocean surface, a 4-DOF motion platform is used. The motion data is transmitted to the visual system and the motion platform through the UDP protocol. Variety of weather conditions are created using the Vega Prime software. The stereoscopic multi-channel visualization and the motion platform system created a realistic simulation system.

The Prehistoric Paintings in the Hall of Bulls of the Lascaux Cave are Identified as Arrays of Constellations and Dark Clouds

  • Kim, Kwang-Tae;Kim, Youngsik
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.47.3-48
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    • 2016
  • 프랑스 몽티냑에 위치한 라스코 동굴에는 오늘날까지 발견된 수많은 구석기시대 동굴벽화 가운데 대표적인 그림들을 보존하고 있다. 동굴 벽화는 대략 BC 15,000년 전 것으로 연구되어 왔으며 최근 몇몇 학자들에 의해서 그 가운데 몇몇 그림들이 별자리를 그린 것이라는 이론이 제기되었다. 본 논문에서는 동굴 그림 가운데 황소 전당에 그려진 벽화를 별자리로 동정해 보았다. 그 결과 이것들이 성좌화임을 발견했다. 그림은 흥미롭게도 별자리와 암흑 성간운을 구별했는데 별자리는 윤곽선으로 그린 반면 검은 성간운은 검은 바탕의 그림으로 나타냈다. 그림은 벽화들의 특징과 구도 그리고 배열순서로 볼 때 전천 성좌도를 그린 것으로 동정되었는데 이는 당시 밤하늘에 보이는 별자리들과 암흑 성간운들의 구도와 배열의 일치에서 신뢰할 수 있었다. 벽화에는 황소자리, 플레이아데스, 오리온삼성, 오리온자리-쌍둥이자리, 사자자리-처녀자리-뱀자리, 천칭자리-사수자리-전갈자리가 그려져 있으며, 특히 은하중심의 사수자리에서 고물자리에 이르는 길다란 은하평면상의 검은 암흑성간운들의 특징적 나열을 들판을 뛰어가는 검은색 동물로 나타냈다. 척도를 감안해서 볼 때, 그림의 구도와 배열순서가 밤하늘에 보이는 것과 거의 같다 할만큼 사실적으로 그려져 있어서 구석기인들이 지적능력이 오늘날 현대인들과 다를 바 없는 수준에 이르렀다고 추정된다.

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Why is Geomancy an Important Research Topic for the Korean Geographers\ulcorner (왜 풍수는 중요한 연구주제인가\ulcorner)

  • 윤홍기
    • Journal of the Korean Geographical Society
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    • v.36 no.4
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    • pp.343-355
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    • 2001
  • Geomancy (feng-shui in Chinese and Pungsu in Korean) has had a significant impact on the Korean culture and is still practiced by many Koreans. This art is thought to have originated from the early Chinese people's search for an ideal site for preparing a cave dwelling. Ever since geomancy was introduced to Korea, it has been a crucial factor in the development of the Korean cultural landscape and the Korean geomentality. The current tendency of avoiding research into geomancy by the Korean geographers might have developed from their desire to avoid wrongly labeling themselves as geomancers and their discipline as geomancy studies. The geographer\`s aim of studying geomancy is not to prove the truthfulness of geomantic doctrines, but is to document and explain the impact of geomancy on the Korean culture.

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A Study on the Status Analysis of Cut Slope in Gyeongnam Region (경남지역 절취사면의 현황분석에 관한 연구)

  • Park, Jin-Kyu;Park, Choon-Sik;Jang, Jeong-Wook
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.862-869
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    • 2005
  • This study examined 233 cut slopes in Gyeongnam region; evaluated hazards and slope conditions involved in the slope; and determined the priority order for reinforcement. The conclusions are summarized in the following. (1) The slopes that need reinforcement or maintenance are 153, accounting for 65.6% of the entire slopes. Slopes with a length of $0{\sim}200m$ account for 70.9%; slopes with a height of $10{\sim}20m$ account for over 50%. (2) Slopes with slope of more than 1:0.5 account for 70.9% of the entire slopes. The steepness of the slope is owing to more rock slopes than soil slopes. (3) The percentages of rock slopes, soil slopes, complex slopes mixed with rocks and soil, and slopes comprised of igneous rocks are 54.4%, 24.9%, 20.7%, and 54.1%, respectively. (4) In the rock area occurred cave-in, plain failure, wedge failure, and overturning failure, in order. Slopes with volcanic rocks are the most unstable, while sedimentary rocks and metamorphic rocks are relatively stable. (5) When the slope height is over 20m, low grade slopes are more than 80%; leading to the conclusion that the higher the slope height is, the more unstable the slope is.

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Seismic Analyses of Soil Pressure against Embedded Mat Foundation and Pile Displacements for a Building in Moderate Seismic Area (중진지역 건축물의 묻힌온통기초에 작용하는 토압과 말 뚝변위에 대한 지진해석)

  • Kim, Yong-Seok
    • Journal of the Earthquake Engineering Society of Korea
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    • v.21 no.1
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    • pp.69-76
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    • 2017
  • Seismic analyses of a pile under a large rigid basement foundation embedded in the homogeneous soil layer were performed practically by a response displacement method assuming a sinusoidal wave form. However, it is hard to take into account the characteristics of a large mat foundation and a heterogeneous soil layer with the response displacement method. The response displacement method is relevant to the 2D problems for longitudinal structures such as tunnel, underground cave structure, etc., but might not be relevant with isolated foundations for building structures. In this study, seismic pile analysis by a pseudo 3D finite element method was carried out to compare numerical results with results of the response displacement method considering 3D characteristics of a foundation-soil system which is important for the building foundation analyses. Study results show that seismic analyses results of a response displacement method are similar to those of a pseudo 3D numerical method for stiff and dense soil layers, but they are too conservative for a soft soil layer inducing large soil pressures on the foundation wall and large pile displacements due to ignored foundation rigidity and resistance.

A Study on the Feature of Plan Type and Space Composition of the Siheyuan Housing in China (중국 사합원의 평면유형과 공간구성의 특징에 관한 개괄적 연구)

  • 최장순
    • Journal of the Korean housing association
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    • v.14 no.5
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    • pp.19-26
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    • 2003
  • The purpose of this paper is to examine and analyse the features of plan type and space composition of the Siheyuan(courtyard house) which is one of the most remarkable types of the traditional dwellings in China. With the passage of time this house developed into one of the chinese house style. The technique of Siheyuan's spatial composition goes so far back in the New Stone Age. The relics of this are the colony layout, the system of four sides, the layout type of a palace, the picture of lacquered ware, the pictured brick, the earthenware of house type, the cave painting, the paintings of painters and others. The fundamental spatial conception of it arranges one or more courtyards to compose, sometimes in a very complex way, a general walled compound. The main longitudinal axis is mainly north-south, but the chief buildings, or halls are always placed transversely to it. These rectangular buildings mayor may not connect, by means of open galleries variously planned, with rows of smaller buildings flanking the courtyards on both sides. On this system, enlargement is never carried out by adding to height, but by continual duplication of existing units, and growth in breadth or preferably depth. The need for family security is thought to have led to the development of this rectangular houses with walls mainly blank on the outside, defensible entrances, and public service facilities in the center of the houses.