• Journal of the Korean Geographical Society
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• v.46 no.4
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• pp.414-425
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• 2011

The aim of this research is to infer paleovegetation and paleoclimate in the Hwajeon archeological site of Gwangju city during mid-Holocene through the analysis of pollen, waterlogged woods, and sediments. Between 8200 ~ 6800 years ago, relatively dry climate resulted in a weakened dominance of oak and high diversity of tree genus. During the Holocene climatic optimum period (6800 ~ 5900 years ago), oak forests expanded while wetland areas diminished as warm/humid climate intensified. Between 5900 ~ 4700 years ago, the entire forest area as well as oak climax forests was reduced due to a relatively cool/dry climate. However at the end of this period, oak forests expanded since a favorable climate condition temporarily resumed. Lastly, between 4700 ~ 3300 years ago, oaks dominated but alders were weakened. The density of forest was low because of a relatively dry climate in this period.

• Journal of Korean Society on Water Environment
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• v.26 no.2
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• pp.243-251
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• 2010

Evapotranspiration and rainfall-runoff are the major components of hydrological cycle and thereby the changes of them can directly affect the wetness/dryness or runoff characteristics of basins. In this study the wetness/dryness in Geum river basin are classified by dint of cumulative probability density function of monthly moisture index and the long term changes of them are analyzed based on climatic water balance concept. The drought events in Geum river basin are selected through evaluation of monthly moisture index and the various hydrological properties of them are investigated in detail. Also the trends of time-series of climatic water balance components are examined by Seasonal Kendall test and the variability of hydrological cycle in Geum river basin during the recent decade is inquired. It is judged that the results of this study can be contributed to establishment of the counter plan against the future drought events as the fundamental information.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.263-266
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• 2008

입력신호인 도로표면의 화상 데이터는 낮 시간대의 아스팔트 포장 도로면을 촬영하여 도로표면 상태의 화상을 만들었고, 편광 및 웨이블릿 변화(Wavelet transform)으로 도로 표면을 5가지의 상태(건조, 습윤, 수막, 적설, 동결)로 인식할 수 있는 분류기준절차를 연구하였다. 표면 화상 인식 과정은 편광계수에 의한 젖은 땅으로 분류한 후, 다음으로 젖은 땅을 제외한 나머지는 웨이블릿 패킷 변환을 통해 시간-주파수 분석을 하였다. 또한 영상 템플릿을 이용하여 마른 땅과 빙판의 표준적인 주파수 특성을 분석하여, 마른 땅과 빙판을 구분하였다. 도로표면영상에서 마른 부분과 젖은 부분을 구분한 결과를 정리하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.487-488
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• 2008

The dry and wet flashover characteristics on the contaminated distribution facilities was investigated. The test were carried out on the suspension insulator, line post insulator, lightning arrester, cut off switch, etc. In the dry state, the flashover voltages of facilities contaminated with B, C, D classes are similar to the non-contaminated ones. However, in the wet state, the flashover voltages of facilities contaminated with B, C, D classes are decreased. The flashover voltages of some few facilities show under the standard value. This results indicate that the high humidity may cause the flashover on distribution facilities.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1640-1644
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• 2010

In this study the wetness/dryness in Geum river basin are classified by dint of cumulative probability density function of monthly moisture index and the long term changes of them are analyzed based on climatic water balance concept. The drought events in Geum river basin are selected through evaluation of monthly moisture index and the various hydrological properties of them are investigated in detail. Also the trends of time-series of climatic water balance components are examined by Seasonal Kendall test and the variability of hydrological cycle in Geum river basin during the recent decade is inquired. It is judged that the results of this study can be contributed to establishment of the counter plan against the future drought events as the fundamental information.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.471-471
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• 2015

토양내의 수분흐름을 이해하는 것은 토양수분의 시공간적 분포변화와 유출기작을 규명하는데 매우 중요하다. 본 연구에서는 설마천유역의 작은 사면에서의 장력측정 시스템을 구축하여, 3차원의 흐름방향에 대해 잠재적 흐름구배를 평가하고자 하였다. 또한 흐름구배를 평가하기 위한 일반적 산술적 계산방법인 평균적 흐름구배와 측정시스템의 구조적 영향 및 흐름구배의 공간적 평가 기준을 고려한 계산방법론을 개발하여 비교 평하였다. 3차원의 흐름방향은 사면의 지표경사를 기준으로 x, y, z축을 기준으로 하여, 각 축 방향에 해당하는 흐름구배 값과 흐름방향을 각각 계산하였다. 그 결과, 강우사상에 따른 토양내의 장력변화는 매우 민감하게 변화하였으며, 이에 따른 각 흐름구배 값과 흐름방향의 반응이 빠르게 반응을 하였다. 특히, 습윤, 건조기간동안의 흐름구배의 발달 및 방향이 바뀌는 천이되는 상태인 흐름 굽힘 현상(flow Bending)을 확인하였다.

• Asian Journal of Turfgrass Science
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• v.7 no.2_3
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• pp.103-112
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• 1993

한국에서의 $C_3$$C_4$CAM 식물의 지리적 분포를 알아보았다. 한국 전체에서 258 군데의 지역에서 모든 초본식물들의 목록을 작성하고 각 식물들의 중요값을 통해 우점종을 결정하였으며 이들 식물의 분류에는 크란츠 해부구조의 존재 관찰을 비롯한 여러가지 방법들을 사용하였다. 이 연구의 결과에 따르면 우리나라의 $C_4$형 초본식물은 총 7개과 92종이었으며 $C_4$식물의 대부분은 화본과 식물이었다. 대한민국에서의 $C_3$와 $C_4$형 초본식물의 분포는 초본식물의 서식지와 관련되어 나타났다. 야외 및 해변의 건조지역에서는 $C_4$형 초본과 조건적 CAM 식물이 주로 서식하고 있는 반면, 습윤 지역에서는 주로 $C_3$형 초본식물이 많이 나타났다. 조사된 총 258개 지역 중에서 잔디가 우점종인 지역은 6개 지역이었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.164-164
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• 2022

대기의 습한 정도는 기상 현상과 밀접한 관계를 가진다. 공기가 건조하면 가뭄이나 산불이, 반대로 습윤하면 홍수나 극한 강우가 내리기 쉽다. 산업화 이후 지구의 평균 기온이 상승하면서, 세계적으로 상대습도가 감소하는 경향성이 보고되고 있다. 이러한 경향이 우리나라에서도 확인되는지 파악하고자, 이 연구에서는 장기간에 걸친 상대습도 관측치가 존재하는 종관기상관측소 6개소의 자료를 분석하였다. 기온은 시간에 따라 증가하고, 포화 수증기압도 그에 따라 증가해온 것으로 나타났다. 하지만, 상대습도의 증감은 포화 수증기압뿐만 아니라 실제 수증기압의 변화에도 민감하게 반응한다. 우리는 실제 수증기압 변화의 원인을 수증기압에 영향을 주는 다양한 기후 변수들의 시계열 자료를 통해 분석해보았다. 우리나라 지역별로 상당한 변동성이 나타났는데, 대표적으로 동해안과 서해안 사이의 차이, 내륙과 해안의 차이에 대해 자세히 발표할 것이다.

• Journal of Oral Medicine and Pain
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• v.30 no.4
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• pp.383-389
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• 2005

Xerostomia is defined as a subjective complaint of dry mouth that may be perceived when there is insufficient mucosal wetting. However, the diagnosis and treatment of xerostomia is not that simple because of the fact that the subjective awareness of dry mouth is not always correlated with a diminution in the flow of saliva and there is always a difference between individuals in salivary flow rates needed for normal oral function. In the present study, the aim was to develop a questionnaire to evaluate the dry mouth symptoms and to analyze its reliability and usability as a diagnostic and analytic tool for xerostomia. The questionnaire which consists of 6 Visual Analogue Scale(VAS) type questions to evaluate the subjective oral dryness and 4 questions to evaluate behavior to avoid oral dryness was developed and administered twice with 1 week's interval to the healthy 88 young adults without dry mouth symptoms(44 males and 44 females; mean age was $25.6{\pm}3.1$ years in male and $24.3{\pm}2.1$ years in female). The results were as follows. 1 The intraclass correlation coefficients of 6 questions to evaluate the subjective oral dryness were as significantly high as 0.767 for the degree of oral dryness at other times of the day, 0.850 for the amount of saliva in the mouth, and 0.791 for the degree of effect on daily life due to oral dryness and as high as 0.563 for the degree of oral dryness at night or on awakening, 0.674 for the degree of oral dryness during eating, and 0.641 for the degree of difficulty in swallowing foods. 2. Cronbach's alpha value of 6 questions was 0.982. It can be concluded that the series of questions to evaluate the subjective oral dryness has high internal consistency. 3. Cohen's kappa values of 4 questions to evaluate behavior to relieve oral dryness were as significantly high as 0.850 for the frequency of keeping a glass of water at the bedside and as high as 0.506 the frequency of awakening during sleeping due to oral dryness, 0.419 for the frequency of sipping liquids to aid in eating dry foods, and 0.407 for the frequency of using a candy or chewing gum due to oral dryness. From the results, it can be concluded that the questionnaire consisting of 6 VAS type questions to evaluate the subjective oral dryness and 4 questions to evaluate behavior to relieve oral dryness has reliability of good to excellent level, and that the series of 6 VAS type questions has significantly high internal consistency to evaluate the subjective oral dryness.

• Restorative Dentistry and Endodontics
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• v.30 no.6
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• pp.435-441
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• 2005

The purpose of this study was to evaluate the effect of increasing application time of single bottle adhesives (SBA) to microtensile bond strength (MTBS) of dried dentin. To expose the superficial dentin surfaces, human molars were sectioned perpendicular to the long axis of tooth. $32\%$ phosphoric acid gels were applied for 15s and rinsed. The teeth were randomly assigned to 3 groups ; S group (Single Bond), O group (One-Step), P group (Prime & Bond NT). Each group was divided to 3 subgroups (W: dentin wipe with wet gauge and light cured immediately, D, dentin dried for 30s and light cured immediately, 30: dentin dried for 30s and light cured after applying SBA for 30s). Composite resin was built up on the dentin surface and sectioned to obtain 20 specimens with $1mm^2$ cross sectional area and the MTBS was measured. For Single Bond, the mean MTBS of S-W and S-30 group were higher than that of S-D group statistically (P<0.05). For One-Step, the mean MTBS of O-D group was statistically lower than that of O-W group (P<0.05). For Prime & Bond NT, the mean MTBS of P-30 group was statistically lower than that of P-D group (P<0.05).