• Korean Journal of Remote Sensing
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• v.25 no.1
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• pp.31-44
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• 2009

The objective of this study was to measure backscattering coefficients of paddy rice using a L-, C-, and X-band scatterometer system with full polarization and various angles during the rice growth period and to relate backscattering coefficients to rice growth parameters. Radar backscattering measurements of paddy rice field using multifrequency (L, C, and X) and full polarization were conducted at an experimental field located in National Academy of Agricultural Science (NAAS), Suwon, Korea. The scatterometer system consists of dual-polarimetric square horn antennas, HP8720D vector network analyzer ($20\;MHz{\sim}20\;GHz$), RF cables, and a personal computer that controls frequency, polarization and data storage. The backscattering coefficients were calculated by applying radar equation for the measured at incidence angles between $20^{\circ}$ and $60^{\circ}$ with $5^{\circ}$ interval for four polarization (HH, VV, HV, VH), respectively. We measured the temporal variations of backscattering coefficients of the rice crop at L-, C-, X-band during a rice growth period. In three bands, VV-polarized backscattering coefficients were higher than hh-polarized backscattering coefficients during rooting stage (mid-June) and HH-polarized backscattering coefficients were higher than VV-, HV/VH-polarized backscattering coefficients after panicle initiation stage (mid-July). Cross polarized backscattering coefficients in X-band increased towards the heading stage (mid-Aug) and thereafter saturated, again increased near the harvesting season. Backscattering coefficients of range at X-band were lower than that of L-, C-band. HH-, VV-polarized ${\sigma}^{\circ}$ steadily increased toward panicle initiation stage and thereafter decreased, and again increased near the harvesting season. We plotted the relationship between backscattering coefficients with L-, C-, X-band and rice growth parameters. Biomass was correlated with L-band hh-polarization at a large incident angle. LAI (Leaf Area Index) was highly correlated with C-band HH- and cross-polarizations. Grain weight was correlated with backscattering coefficients of X-band VV-polarization at a large incidence angle. X-band was sensitive to grain maturity during the post heading stage.

• Journal of Wetlands Research
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• v.23 no.4
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• pp.327-341
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• 2021

The riparian eco-belt is an efficient technique that can reduce non-point pollution sources in the basin and improve ecological connectivity and health. In Korea, a legal system for the construction and management of riparian eco-belts is in operation. However, it is currently excluded that rivers and floodplains in dam reservoir that are advantageous for buffer functions such as control of non-point pollutants and ecological habitats. Accordingly, this study presented and analyzed a plan to select a site for an integrated riparian ecol-belt that comprehensively evaluates the water quality and ecosystem characteristics of each dam floodplain and riparian zone for the Daecheong Dam basin in Geum River watershed. First, the Daecheong Dam basin was divided into 138 sub-basin with GIS, and the riparian zone adjacent to the dam floodplain was analyzed. Sixteen evaluation factors related to the ecosystem and water quality impact that affect the selection of integrated riparian eco-belt were decided, and weights for the importance of each factor were set through AHP analysis. The priority of site suitability was derived by conducting an integrated evaluation by applying weights to sub-basin by floodplains and riparian zone factors. In order to determine whether the sites derived through GIS site analysis are sutiable for actual implementation, five sites were inspected according to three factors: land use, pollution sources, and ecological connectivity. As a result, it was confirmed that all sites were appropriate to apply integrated riparian ecol-belt. It is judged that the riparian eco-belt site analysis technique proposed through this study can be applied as a useful tool when establishing an integrated riparian zone management policy in the future. However, it might be necessary to experiment various evaluation factors and weights for each item according to the characteristics and issues of each dam. Additional research need to be conducted on elaborated conservation and restoration strategies considering the Green-Blue Network aspect, evaluation of ecosystem services, and interconnection between related laws and policy and its improvements.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.9-10
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• 2019

순천만은 순천시의 남쪽에 위치하여 여수반도와 고흥반도의 사이에 있는 만 지형 형태로 만 전체를 순천만이라고도 하나, 보통 고흥군반도와 여수반도 사이의 만을 여자만이라 하고 만내부에 위치한 여자도라는 섬의 위쪽으로 순천시의 해안하구에 형성된 지역을 순천만이라 일컫는다. 순천만은 순천시에서 유입되는 동천과 이사천 및 해룡천의 하류에 형성되어 있어서 육지부에서 유입되는 퇴적물과 유기물로 인하여 갯벌과 갈대등이 잘 형성된 습지로서 2003년 12월 31일 해양수산부 갯벌 습지보존지역으로 지정되어 관리되고 있으며, 2004년에는 동북아 두루미 보호 국제네트워크에 가입하였고, 2006년 1월 국내 연안습지로는 최초로 람사르협약에 "Suncheon Bay"로 등록되었으며, 2016년 6월에는 람사르습지로 지정된 국내외적으로 중요한 습지이다. 순천만습지에 형성되어 있는 갯벌($28.0km^2$)은 세계 5대 연안습지 중 하나로서, 넓은 사니질 갯벌과 갈대군락이 잘 발달되어 있는 생태계의 보고(寶庫)이자 소중한 생태자원으로서, 순천시에서는 순천만을 자연생태공원으로 지정하여 보호 관리하고 있으며, 각종 자연학습자료들과 영상물들을 갖춘 생태전시관과 갈대숲 탐방로, 용산전망대, 야생화 정원, 담수습지, 갈대정자, 갯벌관찰대 등 사계절 생태체험을 위한 각종 시설들을 잘 갖춰놓고 많은 관광객의 이용할 수 있도록 하고 있다. 갯벌은 바닷가의 넓은 벌판이란 뜻으로서 삼면이 바다인 우리나라는 갯벌의 전체 면적이 약 $2,500km^2$에 달하는데 여기에는 많은 종류의 다양한 생물들이 살아가고 있으며 어민들의 생계에 지대한 영향을 주고있다. 이러한 갯벌은 퇴적된 입자의 구성에 따라 펄갯벌, 모래갯벌, 혼합갯벌 등으로 구별되는데 이에 따라 갯벌 생태계를 구성하고 있는 생물들의 종류도 바뀌게 된다. 순천만갯벌과 여기에 조성되어 있는 습지환경에 따라 확인되고 있는 수산자원으로는 새꼬막, 꼬막, 눈알고둥, 갯고둥, 비툴이고둥, 돌조개, 접시조개, 새알조개, 가무락조개, 바지락, 우럭, 가재붙이, 방게, 칠게, 농게 등의 저서 생물들과 짱뚱어, 문절망둑 등의 어류가 있으며, 해조류로 우뭇가사리 등이 있고, 인근의 어민들의 어업형태는 꼬막 등 패류의 채취나 종패를 뿌려 일정기간 양성하여 수확하는 양식업, 육상부에서 폐염전 등을 활용한 전어나 새우 등을 양식하는 양식업, 수산물을 직접 손이나 간단한 도구를 이용하여 잡는 맨손 어업 형태가 주를 이루고 있는 것으로 나타나고 있다. 이와 같이 국내외적으로 중요할 뿐만 아니라 인근의 어민들의 생계에도 지대한 영향을 미치고 있는 순천만의 습지는 뻘층이 깊고, 분해성 미생물이 다양하게 서식하여 유기물 분해능력이 뛰어나며, 유기영양분이 풍부하여 우리나라에서 가장 질이 좋은 습지로 평가되고 있으나, 순천시 등 순천만 인근에 거주하고 있는 인간의 활동에 따른 간섭에 많은 영향을 받고 있으며, 이에 따라 끊임없는 생태환경이 변화하고 있어서 순천만의 효율적인 보전 및 지속가능한 이용을 위해서는 생태계에서 가장 기본적인 요소인 수 저질 환경의 지속적이고 체계적인 조사 및 관리가 필요하다. 한편, 오염물질의 70% 이상은 하천이나 강을 통해서 해역으로 유입된다고 알려져 있기 때문에 생태계의 보고(寶庫)라고 알려진 순천만의 지속적인 보존 및 관리를 위해서는 유입수계 하천의 수질현황 및 오염물질의 주요 배출원을 파악하고, 이에 대한 저감대책을 수립할 필요가 있다. 따라서 본 연구는 순천만의 수저질 특성과 여기에 유입되는 하천의 수질환경 현황 및 오염원을 파악함으로써 순천만의 보전을 위한 효율적 관리방안을 제시하는 것을 목적으로 수행되었다. 연구의 결과에 따르면, 순천만의 수질평가지수에 의한 등급(WQI)은 III등급으로 나타나고 있으며, 득량만, 광양만 등에 비해 비교적 높은 유기물 및 T-N, T-P의 농도 분포를 보이고 있는 것으로 조사되었다. 이는 순천만에 유입되는 하수종말처리장의 방류수와 도시하수가 유입되어 그대로 방류되고 있는 해룡천 및 연안에 위치한 어촌으로부터 직접 방류되고 있는 일부 정화조 유출수 등, 다양한 원인에 의한 것으로 판단되며 이들의 관리가 부실할 경우 순천만의 갯벌과 습지의 지속가능한 생태환경유지는 쉽지 않다. 따라서 이를 효율적으로 관리하기 위해서는 순천만 연안의 오염물질 방류를 총량관리로 전환하여 철저히 관리하는 것이 필요할 것으로 판단된다.

• Journal of Korea Water Resources Association
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• v.53 no.12
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• pp.1159-1172
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• 2020

This study applied deep convolution neural network based on U-Net and SegNet using long period weather radar data to very short-term rainfall prediction. And the results were compared and evaluated with the translation model. For training and validation of deep neural network, Mt. Gwanak and Mt. Gwangdeoksan radar data were collected from 2010 to 2016 and converted to a gray-scale image file in an HDF5 format with a 1km spatial resolution. The deep neural network model was trained to predict precipitation after 10 minutes by using the four consecutive radar image data, and the recursive method of repeating forecasts was applied to carry out lead time 60 minutes with the pretrained deep neural network model. To evaluate the performance of deep neural network prediction model, 24 rain cases in 2017 were forecast for rainfall up to 60 minutes in advance. As a result of evaluating the predicted performance by calculating the mean absolute error (MAE) and critical success index (CSI) at the threshold of 0.1, 1, and 5 mm/hr, the deep neural network model showed better performance in the case of rainfall threshold of 0.1, 1 mm/hr in terms of MAE, and showed better performance than the translation model for lead time 50 minutes in terms of CSI. In particular, although the deep neural network prediction model performed generally better than the translation model for weak rainfall of 5 mm/hr or less, the deep neural network prediction model had limitations in predicting distinct precipitation characteristics of high intensity as a result of the evaluation of threshold of 5 mm/hr. The longer lead time, the spatial smoothness increase with lead time thereby reducing the accuracy of rainfall prediction The translation model turned out to be superior in predicting the exceedance of higher intensity thresholds (> 5 mm/hr) because it preserves distinct precipitation characteristics, but the rainfall position tends to shift incorrectly. This study are expected to be helpful for the improvement of radar rainfall prediction model using deep neural networks in the future. In addition, the massive weather radar data established in this study will be provided through open repositories for future use in subsequent studies.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.3
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• pp.464-477
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• 2013

There is a great need to develop a training program proven to change behavior and improve knowledge. The purpose of this study was to evaluate employee hygiene knowledge, hygiene practice, and cleanliness, before and after HACCP system implementation at one small-size restaurant. The efficiency of the system was analyzed using time-temperature control after implementation of u-HACCP$^{(R)}$. The employee hygiene knowledge and practices showed a significant improvement (p<0.05) after HACCP system implementation. In non-heating processes, such as seasoned lettuce, controlling the sanitation of the cooking facility and the chlorination of raw ingredients were identified as the significant CCP. Sanitizing was an important CCP because total bacteria were reduced 2~4 log CFU/g after implementation of HACCP. In bean sprouts, microbial levels decreased from 4.20 logCFU/g to 3.26 logCFU/g. There were significant correlations between hygiene knowledge, practice, and microbiological contamination. First, personnel hygiene had a significant correlation with 'total food hygiene knowledge' scores (p<0.05). Second, total food hygiene practice scores had a significant correlation (p<0.05) with improved microbiological qualities of lettuce salad. Third, concerning the assessment of microbiological quality after 1 month, there were significant (p<0.05) improvements in times of heating, and the washing and division process. On the other hand, after 2 months, microbiological was maintained, although only two categories (division process and kitchen floor) were improved. This study also investigated time-temperature control by using ubiquitous sensor networks (USN) consisting of an ubi reader (CCP thermometer), an ubi manager (tablet PC), and application software (HACCP monitoring system). The result of the temperature control before and after USN showed better thermal management (accuracy, efficiency, consistency of time control). Based on the results, strict time-temperature control could be an effective method to prevent foodborne illness.