• Journal of the Korean Geographical Society
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• v.39 no.6 s.105
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• pp.845-862
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• 2004

The aim of this study is to investigate distribution characteristics of incised meander cutoff in Gyeonggi and Gangwon Provinces of Central Korea. The density of meander cutoff is highest in the mountain rivers including Naerin and Dongdae flowing on Jeongseon-gun and Inje-gun of Gangwon Province. Most of meander cutoff process has been occurred repeatedly during the Quaternary period, especially concentrated in the period of climatic change between glacial and interglacial stages. In the aspect of the lithology, the density of cutoff is highest in sedimentary rock, but lowest in igneous rock. As for geological structure, its frequency is high at $11{\sim}20km$ westerly away from the Taebaek Mountains, at subsequent channel, lower part of resequent channel, and channels crossing the fault line. The relation between distance from the Taebaek Mountains and altitude is very obvious at the western side of the Taebaek Mountains. The values of altitude, height from riverbed, and stream order are highest at sedimentary rock and lowest at volcanic rock.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.958-964
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• 2010

Histogram Equalization(HE) is one of the well known methods for contrast enhancement. but, it did not applied directly due to side effects such as significant change in brightness or washed out appearance. Many conventional method try to overcome this problem but they did not guarantee various image or depend on user define parameter. In this paper, an Adaptive histogram Compensated Histogram Equalization(ACHE) is proposed for contrast enhancement. ACHE has a parameter that based on median of input image. Histogram of input image is compensated according to parameter. And then finally compensated histogram is equalized. Experimental results show that proposed method suppresses side effects such as detail loss or washed out appearance. Moreover, parameter calculated automatically with low computation complexity. As a result, it could applies FPD directly.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.308-308
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• 2016

기후변화는 하천 수문특성을 변화시켰으며, 이로 인해 홍수와 가뭄과 같은 자연재해로 인한 피해와 발생빈도가 점차 증가하고 있다. 이에 따라 기후변화에 대비한 유역관리를 위해 유역특성을 고려한 정확한 수문예측이 요구되고 있다. 다양한 유역특성 중에서 수문곡선의 감수부는 유역의 토성, 경사, 대수층 특성 등에 영향을 받는다. 하지만 대부분 유출 모의 모형에서는 이를 고려하지 않고 유역 전체가 동일한 감수특성을 가지고 있다고 가정하여 모의를 한다. 이에 본 연구에서는 미계측 유역에서의 유출 모의가 가능한 Soil and Water Assessement Tool(SWAT) 모형을 활용하여 소유역 별 수문곡선의 감수부 특성이 기저유출 모의 결과에 대한 영향을 분석하였다. alpha factor는 SWAT 모형의 다양한 매개변수 중 한가지로 수문곡선의 감수부 특성을 나타내는 매개변수이다. 이에 본 연구에서는 소유역 중에서 실측 유량자료가 활용 가능한 소유역에 대하여 Web-based RECESS를 통해 alpha factor를 직접 산정하였다. 이렇게 산정한 alpha factor를 SWAT 모형에 적용하여 유출 모의를 한 뒤 모의 결과로부터 기저유출을 분리하였다. SWAT 모형의 기본 입력값(default value)을 적용에 따른 기저유출 분리결과와 실측 유량자료로부터 산정된 alpha factor 적용에 따른 기저유출 분리결과를 비교한 결과 실측 유량자료로부터 산정된 alpha factor를 적용 시 기저유출 모의 결과가 실제 기저유출에 더 가까운 값을 나타내었다. 하지만 alpha factor의 산정 방법 특성 상 실측 유량자료 부재시 이를 산정할 수 없다는 한계점이 있다. 이에 실측 유량자료를 이용한 기존의 alpha factor 산정 방법을 대체할 수 있는 alpha factor 산정 방법을 개발한다면 정확한 기저유출 모의가 가능할 것으로 기대된다.

• Journal of Korea Water Resources Association
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• v.53 no.12
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• pp.1109-1117
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• 2020

In this study, results of RUSLE which is most popular equation for estimating sediment and MSDPM and LADMP have been compared and analyzed by applying to real watershed of mountain area. Crop factor (C), preservation factor (P), and soil erosion factor (VM) of RUSLE can be subjectively selected and differently applied. Therefore, effects of those factors were estimated and compared with different values of factors. Furthermore, sediment yield has been estimated by MSDPM and LADMP according to 10, 20, 30, 50, 100, and 200 year return period. From the results, it was found that sediment yield can be resulted with 400% diffrence. And it was also found that MSDPM and LADMP can be applied in mountain area of Korea.

• Annual Conference of KIPS
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• 2013.11a
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• pp.1294-1297
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• 2013

본 논문은 기계학습을 통하여 특허문서를 국제 특허 분류(IPC) 기준에 따라 자동으로 분류하는 시스템에 관한 연구로 잠재 의미 색인 기법을 이용하여 분류의 성능을 높일 수 있는 방법을 제안하기 위한 연구이다. 종래 특허문서에 관한 IPC 자동 분류에 관한 연구가 단어 매칭 방식의 색인 기법에 의존해서 이루어진바가 있으나, 현대 기술용어의 발생 속도와 다양성 등을 고려할 때 특허문서들 간의 관련성을 분석하는데 있어서는 단어 자체의 빈도 보다는 용어의 개념에 의한 접근이 보다 효과적일 것이라 판단하여 잠재 의미 색인(LSI) 기법에 의한 분류에 관한 연구를 하게 된 것이다. 실험은 단어 매칭 방식의 색인 기법의 대표적인 자질선택 방법인 정보획득량(IG)과 카이제곱 통계량(CHI)을 이용했을 때의 성능과 잠재 의미 색인 방법을 이용했을 때의 성능을 SVM, kNN 및 Naive Bayes 분류기를 사용하여 분석하고, 그중 가장 성능이 우수하게 나오는 SVM을 사용하여 잠재 의미 색인에서 명사가 해당 용어의 개념적 의미 구조를 구축하는데 기여하는 정도가 어느 정도인지 평가함과 아울러, LSI 기법 이용시 최적의 성능을 나타내는 특이값의 범위를 실험을 통해 비교 분석 하였다. 분석결과 LSI 기법이 단어 매칭 기법(IG, CHI)에 비해 우수한 성능을 보였으며, SVM, Naive Bayes 분류기는 단어 매칭 기법에서는 비슷한 수준을 보였으나, LSI 기법에서는 SVM의 성능이 월등이 우수한 것으로 나왔다. 또한, SVM은 LSI 기법에서 약 3%의 성능 향상을 보였지만 Naive Bayes는 오히려 20%의 성능 저하를 보였다. LSI 기법에서 명사가 잠재적 의미 구조에 미치는 영향은 모든 단어들을 내용어로 한 경우 보다 약 10% 더 향상된 결과를 보여주었고, 특이값의 범위에 따른 성능 분석에 있어서는 30% 수준에 Rank 되는 범위에서 가장 높은 성능의 결과가 나왔다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.363-363
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• 2022

LID 시설에 대한 모니터링은 인력을 활용한 실강우 모니터링을 진행하고 있으나 LID 시설은 소규모 분산형시설로서 인력을 동원한 식생고사, 강우시 모니터링, 현장답사 등 꾸준한 시설확인에 한계가 있으며, LID 시설을 조성한 이후 적정한 유지관리 방법(주기, 빈도, 항목 등)을 인지하지 못하여 막힘현상, 효율저하, 식물고사 등의 문제가 발생한다. 따라서 본연구에서는 딥러닝 분석을 활용하여 강우시 강우모니터링 자료와 LID 시설 내 센서를 통해 측정된 자료를 통해 침투도랑 내 유입수 성상에 대한 예측분석을 수행하였다. 심지 내 LID 시설에 유입되는 오염물질을 예측을 위한 딥러닝 분석을 위해 과거 실강우시 모니터링 자료(TSS, COD, TN, TP)와 대기센서(대기습도, 대기온도, 강수량, 미세먼지) 데이터를 활용하여 딥러닝 모델에 대한 적용가능성 평가를 수행하였다. 측정항목에 대한 상관성 분석을 수행하였으며, 딥러닝 모델은 Tenser Flow를 이용하여 DNN(Deep Neural Network)모델을 활용하여 분석하였다. DNN 모델에 대한 MSE값은 0.31로 분석되었으며, TSS에 대한 평균 50.6mg/L로 분석되었으며, COD 평균 98.7 mg/L로 나타났다. TN의 평균 2.21 mg/L로 분석되었으며, TP 평균 0.67 mg/L로 나타났다. 상관계수분석결과 TSS는 0.53로 분석되었으며, TN과 TP의 상관계수는 0.10, 0.56으로 나타났다. COD의 상관계수는 0.63으로 TSS와 COD, TP에 대한 예측이 된 것으로 분석되었다. 딥러닝을 통한 LID 시설 내 농도변화 예측시 강우시 센서데이터 값은 조밀해야하며 오염물질 농도와 상관성이 높은 항목들에 대해 계측과 실강우 모니터링 자료를 축적하여 미래에 대한 활용성을 높여야 한다.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.11
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• pp.493-504
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• 2023

The Republic of Korea is located far from the boundary of the earthquake plate, and the intra-plate earthquake occurring in these areas is generally small in size and less frequent than the interplate earthquake. Nevertheless, as a result of investigating and analyzing earthquakes that occurred on the Korean Peninsula between the past two years and 1904 and earthquakes that occurred after observing recent earthquakes on the Korean Peninsula, it was found that of a magnitude of 9. In this paper, the Korean Peninsula Historical Earthquake Record (2 years to 1904) published by the National Meteorological Research Institute is used to analyze the relationship between earthquakes on the Korean Peninsula and statistical self-similarity. In addition, the problem solved through this paper was the first to investigate the relationship between earthquake data occurring on the Korean Peninsula and statistical self-similarity. As a result of measuring the degree of self-similarity of earthquakes on the Korean Peninsula using three quantitative estimation methods, the self-similarity parameter H value (0.5 < H < 1) was found to be above 0.8 on average, indicating a high degree of self-similarity. And through graph visualization, it can be easily figured out in which region earthquakes occur most often, and it is expected that it can be used in the development of a prediction system that can predict damage in the event of an earthquake in the future and minimize damage to property and people, as well as in earthquake data analysis and modeling research. Based on the findings of this study, the self-similar process is expected to help understand the patterns and statistical characteristics of seismic activities, group and classify similar seismic events, and be used for prediction of seismic activities, seismic risk assessments, and seismic engineering.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.762-768
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• 2015

This study examined the integration value of a low level pilotis space, a component that has been often selected as an essential planning element of the recent high-rise apartment complex, and compared the main outdoor unit spaces with that of an average integration value of the individual complexes. Furthermore, this study provided the preliminary data for the next level of research, which is the observation of the pilotis space usage behaviors and the frequency of utilization. The results of this present research are as follows. First, from the main outdoor unit spaces of the high-rise apartment complexes including the pilotis space, a 'complex entrance' or a 'plaza' space showed the highest integration value. Second, the spatial integration value of a pilotis space in a high-rise apartment complex was generally lower that of the integration value of other main outdoor units. Third, from the pilotis spaces of the high-rise apartment complex, those with a 'projecting entry access + pilotis addition type' that did not provide an access to the individual units, had the lowest space utilization rate by the inhabitants; thus, had a high likelihood of the spaces becoming used for illegitimate activities or becoming vacant.

• Journal of the Korean Society of Radiology
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• v.16 no.5
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• pp.603-609
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• 2022

The dose distribution in the human body was evaluated and analyzed through dosimetry data using water phantom, ionization chamber and simulated by Monte Carlo simulation for ^99mTc and ¹⁸F sources, which are frequently used in the nuclear medicine in this study. As a result of this study, it was found that the dose decreased exponentially as the distance from the radioisotope increased, and it particularly showed a tendency to decrease sharply when the radioisotope was separated by 5 cm. It means that a large amount of dose is delivered to an organ located within 4 cm of source's movement path when a source uptake in the human body. Numerically, it was formed in the rage of 0.16 to 2.16 pC/min for ^99mTc and 0.49 to 9.29 pC/min for ¹⁸F. In addition, the energy transfer coefficient calculated using the result was found to be similar to the measured value and the simulation value in the range of 0.240 to 0.260. Especially, when the measured data and the simulation value were compared, there was a difference is within 2%, so the reliability of the data was secured. In this study, the distribution of radiation generated from a source was calculated to quantitatively evaluate the internal dose by radioisotopes. It presented reliable results through comparative analysis of the measurement value and simulation value. Above all, it has a great significance to the point that it was presented by directly measuring the distribution of radiation in the human body.

• Clinical and Experimental Pediatrics
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• v.50 no.1
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• pp.40-46
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• 2007

Purpose : This study assessed the long term survival rate and long term complications of patients who had a modified Fontan operation for functionally univentricular cardiac anomaly. Methods : Between June 1986 and December 2000, 302 patients with a functional single ventricle underwent surgical interventions and were followed up until February 2006. The mean follow-up period was $8.3{\pm}5.3years$ (range 3.5-18 years). Their median age was 2.4 years at the Fontan operation. The survival rate, the incidence and the risk factor of late complications were evaluated retrospectively. Results : The verall survival rate was 91 percent at 5 years and 87 percent at 10 years. In multivariate analysis, early calendar year of operation and significant regurgitation were risk factors of death. The surviving patients showed NYHA functional class I in 82 percent, class II in 15 percent, and class III in 3 percent. Redo Fontan operations were necessary in 8.8 percent of patients at average $12.8{\pm}3.6years$ after initial Fontan operation. The most common cause of Fontan conversion was atrial arrhythmia. The incidence of thromboembolic events was 9.3% and these complications were associated with the occurrence of atrial tachyarrhythmia. Supraventricular tachycardia including atrial flutter or fibrillation were reported on the follow-up examination by 11.2 percent of survivors after $8.4{\pm}5.6years$. Atriopulmonary connection showed higher rates of late tachycardia than lateral tunnel operation. Conclusions : This study revealed that the recent survival rate of Fontan type operation was satisfactory, but the occurrence of late complications after a Fontan type operation increased with the longer survival. There is a need for strict follow up and early treatment of late complications in patients who had a Fontan operation.