• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.8
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• pp.34-40
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• 2017

In recent years, global warming has caused abnormal weather phenomena. Unusually cold climates have occurred all around the world, including cold waves in the Northeastern United States, Beijing, China, Southern India, and Pakistan, as well as floods in Chile, Kazakhstan, and Vietnam. China has been experiencing a nationwide heat wave annually since the year 2013, especially in the southern region. In this study, we used Landsat 8 OLI TIRS sensor images from four periods to analyze the characteristics of abnormal high temperature phenomena in Cixi-si, China. Land cover classification was performed using 10 bands of satellite imagery, and the surface temperature was extracted using the 10th thermal band. The results of the land cover classification of the fourth period show the changes of the time series quantitatively. The results of the surface temperature calculation provided both the average overall temperature and the average temperature of individual items. The temperature was found to be highest for buildings, followed by grassland, forest, agricultural land, water systems, and tidal flats in the same period.

• Korean Journal of Plant Resources
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• v.33 no.1
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• pp.1-14
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• 2020

This study was conducted to analyze community structure and species composition of Pinus densiflora for. erecta Stand in Mt. Cheonchuk (653 m). Field survey was carried out from June to September in 2013. 74 plots (20×20 m) were set up, 5 herb layer plots (3×3 m) were constructed for each plot, and there, Diameter at Breast Heigh t(DBH), height, environmental factor, annual growth were measured. Vascular plants were surveyed as following; 66 family, 165 genus, 211 species, 2 sub species, 29 variety, 6 form 248 taxa. Results of cluster analysis for P. densiflora for. erecta forest, 3 communities were divided into; Quercus mongolica (P-1), Quercus variabilis (P-2) and Quercus aliena-Stephanandra incisa (P-3). There were significant environmental factors that organic layer, annual growth, CEC, total total nitrogen, organic matter and pH for each community. As a result of DCA, P-1 and P-2 were distributed large range of environmental factors but relatively limited in P-3. Distributions of herb layer were affected by sand, cation exchange capacity, silt and total nitrogen. Results of MRPP test for herb layer communities, it was significantly analyzed (A=0.003, P<0.008). Species diversity index was highly recorded in P-3 and influenced by cation exchange capacity, total nitrogen, annual growth in consequence of NMS analysis.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.5
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• pp.563-574
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• 2007

There seems to be a consensus among most people that visibility impairment is the most obvious indicator of air pollution. While considerable evidence on the association between air pollution and health outcomes including death and disease have been established, based on industrial complex areas or huge urban cities, time-series, case-crossover and cohort studies, scarce literature exists on the direct evidence for the association between visibility and adverse health outcomes. Our study is assessed the effect of air pollution measured by visibility impairment on respiratory mortality over a period of six years. Relative risks in respiratory deaths were estimated by a Poisson regression model of daily deaths between $1999{\sim}2004$. Daily counts of respiratory deaths as dependent variable was modelled with daily 24-hr mean visibility measurements (kilometers) as independent variable by means of Poisson regression. This model is controlled for confounding factors such as day of weeks, weather variables, seasonal variables and $PM_{10}$. The results in this study is observed the statistically significant association between an inverse health effect and visibility during the study period for respiratory mortality (percentage change in the relative risk for all aged -0.57%, 95% Cl, $-1.01%{\sim}-0.12%$; for $0{\sim}15$ aged -7.12%, 95% Cl, $-13.29%{\sim}-0.51%$; for 65+ aged -0.43%, 95% Cl, $-0.93%{\sim}-0.06%$ per 1 km increased in visibility). The effect size was much reduced during warm season. Visibility impairment resulting from air pollution is strongly associated with respiratory mortality, especially for children may be spent at outdoor. Our result provides a quick and useful indicator for eliciting the contribution of air pollution to the excess risk of respiratory mortality in Seoul, Korea.

• Tunnel and Underground Space
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• v.25 no.2
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• pp.155-167
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• 2015

The thermal-hydrological-mechanical (T-H-M) behavior of rock mass surrounding a high-temperature cavern thermal energy storage (CTES) operated for a period of 30 years has been investigated by TOUGH2-FLAC3D simulator. As a fundamental study for the development of prediction and control technologies for the environmental change and rock mass behavior associated with CTES, the key concerns were focused on the hydrological-thermal multiphase flow and the consequential mechanical behavior of the surrounding rock mass, where the insulator performance was not taken into account. In the present study, we considered a large-scale cylindrical cavern at shallow depth storing thermal energy of $350^{\circ}C$. The numerical results showed that the dominant heat transfer mechanism was the conduction in rock mass, and the mechanical behavior of rock mass was influenced by thermal factor (heat) more than hydrological factor (pressure). The effective stress redistribution, displacement and surface uplift caused by heating of rock and boiling of ground-water were discussed, and the potential of shear failure was quantitatively examined. Thermal expansion of rock mass led to the ground-surface uplift on the order of a few centimeters and the development of tensile stress above the storage cavern, increasing the potential of shear failure.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.2
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• pp.37-55
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• 1997

최근 선진국가들에서는 전자파 장애 증후군에 관심이 집중되고 있는데, 전자파에 장기 노출 되는 인구에서 뇌암이나 유방암, 백혈병 등의 발생률이 높다는 보고(Kolmodin-Hedman 등, 1988 ; Demers등, 1991)가 있어서 전자제품의 생산업체는 물론이고 사용자에 대해서도 불안한 관심사가 되 어 있다. 전자파가 생체에 미치는 영향은 열적 효과와 비열적 효과에 의한 것으로 구분된다. Microwave는 약 300MHz에서 300GHz 사이(파장 1m에서 1mm사이)의 주파수를 가지는 전자파로서 이온의 운동이나 쌍극자분자(dipole molecule)들을 진동시키므로서 조직에 열이 발생한다. 열이 과도하게 발생하면 세포 단백질이 응고하게 되는 등 일반적으로 생각할 수 있는 고열로 인한 여러 가지 유해환경이 조직 에 조성될 수 있다. 실제로 고전압의 전자파에 노출된 안구의 수정체에 백내장 등의 병변이 발생한 것 으로 보고된 바 있다(Adey,1981). 일반적으로 전자파의 생체에 대한 작용으로는 이렇듯 조직에 흡수 되는 전자파의 에너지에 의한 열작용이 지배적인 것으로 생각되어 왔다. 그러나 초저주파역대(Extre- mely low frequency, EMF)의 변조 및 펄스파 등의 영향에 관해서도 조직의 온도상승으로는 설명할 수 없는 현상이 보고된 바 있다. 이러한 비열적 효과가 신경계에 끼치는 영향에 대해서는 혈액뇌관문 의 투과성 변화(Oscar와 Hawkins, 1977), 뇌종양 발생, 칼슘대사 이상 및 신경전달물질에 대한 영향 등이 주장(Anderson, 1993)되고 있으나 아직 그 분명한 기전이 밝혀져 있지 않은 상태이다. 또한 그 영향의 평가에 서도 일정한 기준이나 지표가 정해지지 않은 실정이다. 그러므로 신경계에 대한 대체적인 소개와 더불어 전자기파의 영향에 대한 이제까지의 보고를 종합 하고 향후 연구의 방향을 소개하고자 한다.> 이온이 공동 첨가제로 더 적합하다.u(30 .angs. )/CoFe(35 .angs. )/NiO(800 .angs. ) 구조를 갖는 spin-valve 박막은 극대 MR비 6.3%, 유효자기장감응도 약 0.5(%/Oe)를 보여 spin-valve head 재료로 적합함을 알 수 있었다.다.다.다.는 각각 148 meV .angs. $^{2}$, 103.8 meV .angs. $^{2}$와 1.77 * $10^{-6}$ erg/cm, 0.67 * $10^{-6}$ erg/cm 였다.다.자 노인들을 영주권자와 귀화 시민권자의 구분없이 하나의 집단으로 간주하고 분석해 왔던 것을 볼 때, 앞으로의 연구는 이론적으로나 방법론적으로 시민권의 유무가 주거형태에 끼치는 영향도 함께 고려해야 할 것이다.에 나타난 인도의 영향은 여성복식과 남성복식에 있어서 서로 유사점과 차이점이 보이는데, 인도의 영향이 여성복식에 있어서 그 빈도가 더 높고, 종류가 더 다양함을 볼 수 있다. 여성복식에 있어서는 12가지의 다양한 인도복식스타일이 나타났으며, 그중 가장 많이 보이는 스타일은 Indian Shirt/Blouse/Smock/ Dress이며, 그 뒤를 이어 Madras, Indian lowery등을 볼 수 있다. 남성복식애 나타난 7가지의 스타일 중에는 Madras가 가장 빈도가 높으며 그외의 스타일들은 그 빈도가 매우 낮음을 볼 수 있다. 인도의 영향의 정도 (Attribution Categories) 있어서는 여성과 남성복식 모두에 있어서 인도에서 직접 수입된(originated) item이 각각 전체의 90%와 81%를 차지하여, 인도복식의 영향은 받았으나 미국내에서 제작된(attributed and connotated) item 보다 휠씬 더 많은 수를 보였다. 인도복식스타일이 가장

• Proceedings of the Korean Quaternary Association Conference
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• 2006.11a
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• pp.23-25
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• 2006

제4기 만빙기에서 후빙기 사이의 기후변화는 인류문명에 있어 정착생활 및 농경활동과 더불어 잉여생산물 저장을 위한 토기제작 등과 같은 생활상의 변화를 가져 온 계기가 되었다(F.M. Chambers, 1993; Guoyu Ren, 1998; Mori Y, 2002; Martin Bell et al., 2004). 식물화석, 화분, 식물규소체 등의 대리자료(proxy data)를 이용하여 이시기의 식생환경을 밝히는 것은 고생태복원분야 뿐 아니라 당시의 환경변수들 을 추정하여 인간활동에 어떠한 영향을 미쳤는지에 대한 중요한 정보를 제공해준다. 그러나 홀로세 초기 환경은 인간에게 지대한 영향을 미쳤으나 후기로 올수록 인간 스스로가 환경을 변화시키는 주체가 되었다(Martin Bell et al., 2004). Meyer&Turner(1994)는 인간활동이 자연적인 영향보다 생물구에 시계열적인 변화를 가져왔다고 하였으며, R.B Singh(1995)는 현재뿐 아니라 과거까지 다양한 인위 적인 간섭이 전지구적인 환경변화를 야기 시키는 주된 원인이라고 하였다. 따라서 환경을 복원한다는 것은 바로 그 지역을 생활 터전으로 삼았던 당시 선사인들의 생활상을 간접적으로 들여다 볼 수 있는 기회를 제공해준다. 현재까지 국내 고고학 유적지에서 이루어진 대부분의 발굴조사는 유물과 유구를 토대로 당시 선사인의 생활상을 밝히는데 중점을 두었으나 최근 인간과 영향을 주고 받았을 환경에 관심을 갖고 이를 통해 역으로 인간활동을 추적하려는 다수의 연구들이 제4기학, 고고학, 지리학, 인류학, 생물학, 농학, 기후학 등 다양한 분야에서 학제간 연구로 진행되고 있다(황상일 등, 1999; 조현종, 2000; 김주용 등, 2002; 최정민, 2004; 윤순옥 등, 2005). 그러나 이러한 연구에 있어서 어떠한 대리자료(proxy data)를 어떻게 고고학 유적지에 적절하게 적용시킬 것인지 대리자료의 조성변화나 값의 해석에 있어서 기후인자와 인간영향을 어떻게 분리해 낼 것인지에 대한 문제점이 남는다. 예를 들어 화분분석의 경우 1차적인 환경변화에 따른 식생조성변화를 반영한다. 인간이 활발한 농경활동을 하게 되면서 주변식생을 제거하게 되고, 제거된 나대지에는 재배작물과 잡초들이 자라게 된다. 그리고 이들 화분은 주변 소택지에 퇴적물과 함께 퇴적되어 화분분석 결과 벼과(科)(Gramineae)와 문화지표수종이라 부르는 여뀌속(屬)(Persicaria), 국화과(科)(Composite), 쑥속(屬)(Artemisia), 쐐기풀속(屬)(Urtica) 등의 화분에 있어 확연한 조성변화를 보여준다. 그러나 화분을 이용한 분석은 토탄층이나 유기질 퇴적물이라는 한정된 토양에서만 분석이 가능하며, 조성변화에 있어서 역시 기후와 인간활동의 영향 모두를 반영하기 때문에 이를 구분해 주는 명확한 기준이 필요하다. 따라서 본 연구에서는 이러한 다양한 대리자료 중 고고학 유적지에 적용 가능한 동식물 화석 및 미화석, 지리, 지질학적 자료에 어떠한 것들을 적용할 수 있는지를 살피고, 몇 가지 대리자료를 중심으로 선사인의 농경활동에 대해 살펴보고자 한다.

• Korean Journal of Remote Sensing
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• v.33 no.3
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• pp.287-299
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• 2017

The Southern Volcanic Zone (SVZ) of Chile consists of many volcanoes, including the Mt.Villarrica and Mt.Llaima, and the two volcanoes are covered with snow at the top of Mountain. The purpose of this study is to analyze the relationship between the ice caps and the volcanic activity of the two volcanoes for 25 years by using the satellite image data are available in a time series. A total of 60 Landsat-5 TM and Landsat-7 ETM + data were used for the study from September 1986 to February 2011. Using NDSI (Normalized Difference Snow Index) algorithm and SRTM DEM, snow cover and snowline were extracted. Finally, the snow cover area, lower-snowline, and upper-snowline, which are quantitative indicators of snow cover change, were directly or indirectly affected by volcanic activity, were extracted from the satellite images. The results show that the volcanic activity of Villarrica volcano is more than 55% when the snow cover is less than 20 and the lower-snowline is 1,880 m in Llaima volcano. In addition, when the upper-snowline of the two volcanoes is below -170m, it can be confirmed that the volcano is differentiated with a probability of about 90%. Therefore, the changes in volcanic snowfall are closely correlated with volcanic activity, and it is possible to indirectly deduce volcanic activity by monitoring the snow.

• Clean Technology
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• v.25 no.1
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• pp.33-39
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• 2019

A.C (activated carbon) is mainly used to remove VOCs (volatile organic compounds), however, it has many problems such as fire risk due to increasing of adsorbent surface temperature during VOCs ad/desorption, increased cost by frequent replacement cycles requirement and performance degradation when containing moisture. In order to solve these problems, many researches, hydrophobic zeolite adsorbents, have been reported. In this study, $NH_4{^+}Y$-zeolite was synthesized with Y-zeolite through steam treatment and acid treatment, which is one of the hydrophobic modification methods, to secure high surface area, thermal stability and humidity resistance. The Y, Y-550-HN, Y-600-HN and Y-650-HN had adsorption capacities of $23mg\;g^{-1}$, $38mg\;g^{-1}$, $77mg\;g^{-1}$, $61mg\;g^{-1}$. The change of Si/Al ratio, which is an index to confirm the degree of modification, was confirmed by XRF (X-ray fluorescence spectrometer) analysis. As a result, the adsorbtion performance was improved when Y-zeolite modified, and the Si/Al ratio of Y, Y-550-HN, Y-600-HN, Y-650-HN were increased to 3.1765, 6.6706, 7.3079, and 7.4635, respectively. Whereas it was confirmed that structural crystallization due to high heat treatment temperature affected performance degradation. Therefore, there is an optimal heat treatment temperature of Y-zeolite, optimum modification condition study could be a substitute for activated carbon as a condition for producing an adsorbent having high durability and stability.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.2
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• pp.171-182
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• 2022

InSAR (Interferometry SAR) technique is a technique that uses complex data to obtain phase difference information from two or more SAR image data, and enables high-resolution image extraction, surface change detection, elevation measurement, and glacial change observation. In many countries, research on the InSAR technique is being conducted in various fields of study such as volcanic activity detection, glacier observation in Antarctica, and ground subsidence analysis. In this study, a case of large ground settlement due to groundwater level drawdown during tunnelling was introduced, and ground settlement analyses using InSAR technique and numerical analysis method were compared. The maximum settlement and influence radius estimated by the InSAR technique and numerical method were found to be quite similar, which confirms the reliability of the InSAR technique. Through this case study, it was found that the InSAR technique reliable to use for estimating ground settlement and can be used as a key technology to identify the long-term ground settlement history in the absence of measurement data.

• Korean Journal of Remote Sensing
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• v.37 no.2
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• pp.211-220
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• 2021

Land Surface Temperature (LST) is one of the useful parameters to diagnose the growth and development of crop and to detect crop stress. Unmanned Aerial Vehicle (UAV)-based LST (LSTUAV) can be estimated in the regional spatial scale due to miniaturization of thermal infrared camera and development of UAV. Given that meteorological variable, type of instrument, and surface condition can affect the LSTUAV, the evaluation for accuracy of LSTUAV is required. The purpose of this study is to evaluate the accuracy of LSTUAV using LST measured at ground (LSTGround) under various meteorological conditions and growth phases of garlic crop. To evaluate the accuracy of LSTUAV, Relative humidity (RH), absolute humidity (AH), gust, and vegetation index were considered. Root mean square error (RMSE) after minimizing the bias between LSTUAV and LSTGround was 2.565℃ under above 60% of RH, and it was higher than that of 1.82℃ under the below 60% of RH. Therefore, LSTUAV measurement should be conducted under the below 60% of RH. The error depending on the gust and surface conditions was not statistically significant (p-value < 0.05). LSTUAV had reliable accuracy under the wind speed conditions that allow flight and reflected the crop condition. These results help to comprehend the accuracy of LSTUAV and to utilize it in the agriculture field.