• Korean Journal of Remote Sensing
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• v.22 no.6
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• pp.581-593
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• 2006

Various geological thematic maps have been generated by interpolating sparsely sampled ground survey data and geostatistical kriging that can consider spatial correlation between neighboring data has widely been used. This paper applies multi-variate geostatistical algorithms to integrate secondary information with sparsely sampled ground survey data for geological thematic mapping. Simple kriging with local means and kriging with an external drift are applied among several multi-variate geostatistical algorithms. Two case studies for spatial mapping of groundwater level and grain size have been carried out to illustrate the effectiveness of multi-variate geostatistical algorithms. A digital elevation model and IKONOS remote sensing imagery were used as secondary information in two case studies. Two multi-variate geostatistical algorithms, which can account for both spatial correlation of neighboring data and secondary data, showed smaller prediction errors and more local variations than those of ordinary kriging and linear regression. The benefit of applying the multi-variate geostatistical algorithms, however, depends on sampling density, magnitudes of correlation between primary and secondary data, and spatial correlation of primary data. As a result, the experiment for spatial mapping of grain size in which the effects of those factors were dominant showed that the effect of using the secondary data was relatively small than the experiment for spatial mapping of groundwater level.

• Korean Journal of Remote Sensing
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• v.39 no.3
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• pp.257-268
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• 2023

Sea ice plays an important role in Earth's climate by regulating the amount of solar energy absorbed and controlling the exchange of heat and material across the air-sea interface. Its growth, drift, and melting are monitored on a regular basis by satellite observations. However, low-resolution products with passive microwave radiometer have reduced accuracy during summer to autumn when the ice surface changes rapidly. Synthetic aperture radar (SAR) observations are emerging as a powerful complementary, but previous researches have mainly focused on winter ice. In this study, sea ice drift tracking was evaluated and analyzed using SAR images and tracker with global positioning system (GPS) during late summer-early autumn period when ice surface condition changes a lot. The results showed that observational uncertainty increases compared to winter period, however, the correlation coefficient with GPS measurements was excellent at 0.98, and the performance of the ice tracking algorithm was proportional to the sea ice concentration with a correlation coefficient of 0.59 for ice concentrations above 50%.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.2
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• pp.79-87
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• 2009

Pot experiments using sand culture were conducted in 2004 under greenhouse conditions to evaluate the effect of nitrogen deficiency on red pepper biomass. Nitrogen stress was imposed by implementing 6 levels (40% to 140%) of N in Hoagland's nutrient solution for red pepper. Canopy reflectance measurements were made with hand held spectral sensors including $GreenSeeker^{TM}$, $Crop\;Circle^{TM}$, and $Field\;Scout^{TM}$ Chlorophyll meter, and a spectroradiometer as well as Minolta SPAD-502 chlorophyll meter. Canopy reflectance and dry weight of red pepper were measured at five growth stages, the 30th, 40th, 50th, 80th and 120th day after planting(DAT). Dry weight of red pepper affected by nitrogen stress showed large differences between maximum and minimum values at the 120th DAT ranged from 48.2 to $196.6g\;plant^{-1}$, respectively. Several reflectance indices obtained from $GreenSeeker^{TM}$, $Crop\;Circle^{TM}$ and Spectroradiometer including chlorophyll readings were compared for evaluation of red pepper biomass. The reflectance indices such as rNDVI, aNDVI and gNDVI by the $Crop\;Circle^{TM}$ sensor showed the highest correlation coefficient with dry weight of red pepper at the 40th, 50th, and 80th DAT, respectively. Also these reflectance indices at the same growth station was closely correlated with dry weight, yield, and nitrogen uptake of red pepper at the 120th DAT, especially showing the best correlation coefficient at the 80th DAT. From these result, the aNDVI at the 80th DAT can significantly explain for dry weight of red pepper at the 120th DAT as well as for application level of nitrogen fertilizer. Consequently ground remote sensing as a non-destructive real-time assessment of plant nitrogen status was thought to be a useful tool for in season nitrogen management for red pepper providing both spatial and temporal information.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.27-27
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• 2022

본 연구는 본 연구에서는 내륙에 위치한 하천(백제보)과 호소(남양호)를 대상으로 수체반사도를 활용하여 유역특성에 따른 반사도의 변화를 확인하고 Chlorophyll-a(Chl-a)의 농도를 추정하고자 하였다. 각 유역별 특성분석을 위해 제원자료, 토지피복도 및 11개(수소이온농도, 용존산소, BOD, COD, 부유물질, 총질소, 총인, 수온, 전기전도도 및 Chlorophyll-a)의 수질인자 자료를 구축하였다. 백제보는 2016-2017년 유인항공기에 탑재된 초분광센서를 이용하여 반사도를 측정하였고, 남양호는 2020-2021년 초분광센서가 탑재된 Drone과 Sentinel-2 MSI영상으로부터 반사도를 측정하였으며 두 유역 모두 촬영 범위에 대하여 현장샘플링을 실시하였다. 유역특성, 수질인자간 상관성 및 밴드별 상관성 분석을 실시하였다. 수질인자 간 상관성 분석 결과 Chl-a와 광학적 특징이 있는 SS, TOC가 상관성이 높게 나타났으며, 반사도의 경우 Chl-a가 고농도일수록 Near-Infrared, Blue 파장과 상관성이 높게 나타났다. 해당 분석결과를 기반으로 각 유역에 대해 Chl-a Machine-learning 기법과 원격탐사자료를 이용하여 Chl-a의 농도를 산정하였으며 백제보, 남양호 각각 결정계수(R²) 0.80, 0.88의 성능을 보였다. 추후 고해상도 광학위성영상을 통해 유역특성을 고려한 광범위한 지역 규모의 Chl-a의 시공간적 분석이 가능할 것으로 판단된다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.843-848
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• 2002

It is studied on the relationship between the occurrence of red tide and the meteorological factors(precipitation, air temperature, sunshine and winds) in the middle coastal area in the South Sea of Korea. In summer and early-fall which frequently occurred the red tide, the precipitation had directly influence on the occurrence of red tide because it carried the nutritive substances which originated from the land into the coastal areas. Then air temperature kept up generally high values, and sunshine and winds showed not directly the relationship on the occurrence of red tide.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5B
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• pp.437-444
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• 2010

Soil moisture has been recognized as the essential parameter when understanding the complicated relationship between land surface and atmosphere in water and energy recycling system. It has been generally known that it is related with the temperature, wind, evaporation dependent on soil properties, transpiration due to vegetations and other constituents. There is, however, little research concerned about the relationship between soil moisture and these constitutes, thus it is needed to investigate it in detail. We estimated the soil moisture and then compared with field data using the hydrometerological data such as atmospheric temperature, specific humidity, and wind obtained from the Flux tower in Selmacheon, Korea. In the winter season, subterranean temperature showed highly positive correlation with soil moisture while it was negatively correlated from the spring to the fall. Estimation of seasonal soil moisture was compared with field measurements with the correlation of determination, R=0.82, 0.81, 0.82, and 0.96 for spring, summer, fall, and winter, respectively. Comprehensive relationship from this study can supply useful information about the downscaling of soil moisture with relatively large spatial resolutions, and will help to deepen the understanding of the water and energy recycling on the earth's surface.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.505-509
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• 2002

남해 중부해역에서 적조발생과 관련해서 적조 다발월인 여름과 초가을에 기온과 마찬가지로 높은 수온을 유지한다. 또한 많은 강수량에 의하여 부유물질 및 영양염류가 증가하고 염분이 대체로 떨어지는 것을 알 수 있었다. 이때 적조의 bloom으로 인하여 대표적인 영양염류인 질소와 인의 값이 떨어진다. 그리고 적조생물의 사후 미생물 분해 작용이 활발하여 산소의 소모가 증가하여 용존산소가 급격히 떨어지고 화학적산소요구량이 높게 나타나는 것을 알 수 있었다. 즉, 해양인자와의 상관성은 적조의 발생조건인 수온이 적당하며 저염분과 부유물질, 클로로필, 질소, 인이 높게 나타났고 용존산소는 적조생물의 인해 낮게 나타났음을 알수 있었다.

• Korean journal of applied entomology
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• v.52 no.4
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• pp.341-348
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• 2013

We desinged and evaluated a remote-sensing sex pheromone trap for real-time monitoring of Mythimna separata (Lepidoptera: Noctuidae), a migratory insect in Korea. The system consisted of a modified cone-trap with a sex pheromone lure, a sensing module based on light interruption, a signal transmission module based on code division multiple access, a main electronic board for system control, a power supply based on a solar collector, a stainless steel-pole supporting the system, and a signal collection and display system based on an internet web page. The ratio (>92%) of the actual number of insects to the signal number in the remote-sensing trap was improved by sensing only within a limited period at night on the basis of the insect's circadian rhythm, control of signal sensitivity on the basis of sensing software programming, 1-h interval for signal transmission, and adjustment of the signal transmission program. The signal occurrence pattern in the remote-sensing trap was conclusively similar (correlation coefficient, >0.98) to the actual pattern of adult occurrence in the trap. The result indicated that the remote-sensing trap based on the attraction of the sex pheromone lure for M. separata has a promising potential for practical use. Occurrence of M. separata adults was observed several times in 2011 and 2012, and the peaks were sharp.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1541-1555
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• 2022

Red tide has potential to harm marine ecology and aquaculture. Research on detecting red tide using various optical remote sensors has been conducted, but most of existing algorithms for detecting red tide has limitations, especially in shallow coastal waters with high levels of suspended sediment. For enhanced understanding of the optical behavior of red tide waters, analysis on remote sensing reflectance and water constituent is becoming increasingly important. This study analyzed the optical remote sensing data and water quality variables(Chl-a_(Spec), SPM, a_ph, a_d, Turbidity, Chl-a_(HPLC), Dominant species) of red tide waters. The data were collected from ship-based campaigns. In addition to the research on detecting red tide, the remote sensing reflectance and extinction coefficients for mesodinium and cochlodinium species were also analyzed. Through the analysis, it was possible to estimate the red tide chlorophyll concentration based on a specific wavelength of the remote sensing reflectance. The study found that chlorophyll concentration and phytoplankton absorption coefficient were highly correlated(R²=0.9), and that the RE_diff formula provided a more accurate estimate of red tide concentration than the B-G ratio.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1993.05a
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• pp.85-85
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• 1993

The clinical staging system for laryngeal cancers is not sufficient for prognosticator due to different biologic characteristics and their microenvironment according to primary sites. For determining the prognosticators, the authors peformed immunohistochemical staining to EGFR, p53 protein, and pRB in 40 cases of surgically treated squamous cell carcinomas of larynx in our institute during the past 5 years. The results are as followings; 1. The positive expression rate of p53 protein and negative expression rate of pRB showed correlations with clinical parameters. 2. The three-year survival rate for p53 protein positive cases was worse than the p53 protein negative cases. 3. Expression rate of EGFR was not correlated with the clinical parameters. As a conclusion, expression rates of p53 protein and pRB not only reflect well the biologic behavior of laryngeal cancer, but correlate closely with the tumor factors. Therefore they may be useful as the prognosticator to predict the malignant potency of laryngeal squamous cell carcinomas.