유역 집중시간 및 저류상수의 이론적 배경과 경험식

이지호,유철상,신지예,Lee, Jiho,Yoo, Chulsang,Sin, Jiye 한국수자원학회 2013 한국수자원학회논문집 Vol.46 No.2

This study proposes proper forms of empirical formulas for the concentration time and storage coefficient based on their theoretical backgrounds and evaluates several existing empirical formulas by comparing them with the formula proposed in this study. Additionally, empirical formulas for the concentration time and storage coefficient of the Chungju Dam basin were derived using the forms proposed by considering their theoretical backgrounds, and compared with exiting empirical formulas. The results derived are summarized as follows. (1) The concentration time of a basin is proportional to the square of the main channel length, but inversely proportional to the channel slope, as the flood flow is generally turbulent. (2) The storage coefficient is proportional to the concentration time. (3) The comparison results with existing empirical formulas for the concentration time indicates that the empirical formulas like the Kirpich, Kraven (I), Kraven (II), California DoT, Kerby, SCS, and Morgali & Linsley are in line with the form proposed in this study. Among existing empirical formulas for the storage coefficient, the Clak, Russell, Sabol and Jung are found to be well matched to this study. (4) The application results to Chungju Dam basin indicates that among empirical formulas for the concentration time, the Jung, Yoon, Kraven (I), and Kraven (II) show relatively similar results to the observed in this study, but the Rziha shows abnormal results. Among the empirical formulas for the storage coefficient, the Yoon and Hong, Jung, Lee, and Yoon show somewhat reasonable results, but the Sabol shows abnormal results. In conclusion, the empirical formulas for the concentration time and storage coefficient developed in Korea are found to reflect the basin characteristics of Korea better.

모수 절약 주기적 자기회귀 모형에 관한 연구

이지호,성병찬,Lee, Jiho,Seong, Byeongchan 한국통계학회 2016 응용통계연구 Vol.29 No.1

This paper proposes a parsimonious periodic autoregressive (PAR) model. The proposed model performance is evaluated through an analysis of Korean unemployment rate series that is compared with existing models. We exploit some common features among each seasonality and confirm it by LR test for the parsimonious PAR model in order to impose a parsimonious structure on the PAR model. We observe that the PAR model tends to be superior to existing seasonal time series models in mid- and long-term forecasts. The proposed parsimonious model significantly improves forecasting performance.

다목적 최적화 기법을 이용한 수위관측망 평가

이지호,주홍준,김형수,전환돈,Lee. JiHo,Joo. HongJun,Kim. HungSoo,Jun. HwanDon 한국방재학회 2014 한국방재학회논문집 Vol.14 No.4

본 연구에서는 남강댐 유역을 대상으로 수위관측소의 수문정보량과 설치목적별 중요도를 고려하여 수위관측망을 평가하였다. 엔트로피 이론을 적용하여 산정된 수문정보량과 설치목적별 중요도를 동시에 고려하기 위해 유클리디언 거리를 이용하여 2개의 목적함수를 통합하였으며, 이를 다목적 최적화 기법을 이용하여 최적관측망을 선정하였다. 최적 수위관측망을 구축하기 위해 대표단위도를 실제 강우-유출 해석을 결과를 바탕으로 유도한 후 확률밀도함수로의 전이를 통해 엔트로피 이론에 적용하였다. 아울러 설치목적별 중요도는 MLIT(2010)에서 조사한 수위관측소별 설치목적을 참조하여 등급을 정량화 하였다. 이를 남강댐에 유역에 적용한 결과 다목적 최적화 기법을 이용하여 수위관측망을 평가한 경우가 엔트로피 이론만을 적용했을 때보다 관측소의 설치목적을 보다 잘 만족함을 확인하였다. 이는 수위관측소의 설치목적별 중요도와 자료의 특성이 동시에 반영된 결과이다. 아울러 대상유역인 남강댐 유역에서는 총 12개의 수위관측소 중 8개의 수위관측소가 필요한 것으로 판단된다. This study has evaluated the stream gauge network which is considered the total hydrological information and the importance class of stream gauge stations, and is applied to Namgang Dam basin. The total hydrological information and the importance class of stream gauge stations are two different physical parameters. We adopt the Euclidean distance method to consider them simultaneously. An equation obtained by the Euclidean distance method is used as the objective function in multiobjective optimization method to determine the optimal combination of the stream gauge stations for satisfying the both criteria: the maximum total amount of the hydrological information and the importance class of stream gauge stations. To evaluate the optimal stream gauge network, the representative unit hydrograph which is derived by real rainfall-runoff analysis is transferred into probability density function for the application of entropy theory concept. The importance class of stream gauge stations is determined by referring the result of MLIT (2010). As result of applying to Namgang Dam basin, The optimal stream gauge network obtained by the suggested method shows more satisfied the importance of stream gauge station purpose than the optimal stream gauge network obtain by the entropy theory only. This result implies that the optimal steam gauge network by the suggested method can consider both the total hydrological information and the importance class of stream gauge station. It is found that Namgang Dam basin needs at least 8 steam gauge stations among 12 steam gauge stations.

DCC 모형에서 동태적 상관계수 추정법의 효율성 비교

이지호,성병찬,Lee, Jiho,Seong, Byeongchan 한국통계학회 2015 응용통계연구 Vol.28 No.5

We compare the performance of two representative estimation methods for the dynamic conditional correlation (DCC) GARCH model. The first method is the pairwise estimation which exploits partial information from the paired series, irrespective to the time series dimension. The second is the multi-dimensional estimation that uses full information of the time series. As a simulation for the comparison, we generate a multivariate time series similar to those observed in real markets and construct a DCC GARCH model. As an empirical example, we constitute various portfolios using real KOSPI 200 sector indices and estimate volatility and VaR of the portfolios. Through the estimated dynamic correlations from the simulation and the estimated volatility and value at risk (VaR) of the portfolios, we evaluate the performance of the estimations. We observe that the multi-dimensional estimation tends to be superior to pairwise estimation; in addition, relatively-uncorrelated series can improve the performance of the multi-dimensional estimation.

울산지역 초등학생의 알레르기비염 유병과 면역반응과의 상관성: 환자-대조군 연구

이지호,오인보,김아라,김민호,심창선,김양호,Lee, Jiho,Oh, Inbo,Kim, Ahra,Kim, Minho,Sim, Chang sun,Kim, Yangho 한국환경보건학회 2015 한국환경보건학회지 Vol.41 No.4

Objectives: This study aims to investigate the correlations between the prevalence of allergic rhinitis (AR) and cytokines among elementary school children in an industrial city, Ulsan, South Korea, and to identify major environmental risk factors associated with AR prevalence. Methods: We conducted a case-control study in June 2009 and February 2010 in order to evaluate the relationship between AR and related cytokines. Data on physician-treated prevalence over the past 12 months and potential risk factors for AR were compiled through a questionnaire from a survey of 339 schoolchildren living in different urban environments. Logistic regression analysis was carried out with propensity score matched data (n=180) to assess the influences of cytokines (IL-13, IL-33, IL-4 and IL-5) on AR prevalence and to determine which environmental factors affected AR. Results: In univariate analysis, the AR prevalence was influenced by family history of AR (mother and siblings), environmental factors (odor condition and irritated symptoms of air pollution), and indoor allergens (D. farinae and D. pteronyssinus). The t-test demonstrated that eosinophils, Immunoglobulin E (IgE), and interleukins (IL-13 and IL-5) were statistically significantly different according to treatment of allergic rhinitis over the preceeding 12 months. The results of the multiple logistic regression analysis showed that a statistically significant association between several factors (such as irritated symptoms of air pollution (OR 4.075, CI 1.735-9.568), IL-13 (OR 0.825, CI 0.734-0.928), odor condition (OR 2.409, CI 0.908-6.389), and AR history of siblings (OR 2.217, CI 0.999-4.921)) and the prevalence of AR was found after adjusting for confounders. Conclusion: These results suggest that AR prevalence is significantly associated with cytokine level, genetic background, and outdoor environmental factors. Although living in a polluted area and genetic background can contribute to an increased risk of childhood AR, cytokine level should be considered as an important factor in the treatment of AR in the last 12 months.

다기준의사결정기법을 이용한 도시 중소유역 홍수위험도 평가

이지호(Lee Jiho),전환돈(Jun Hwandon),최종원(Choi Jongwon),박재범(Park Jaebeom) 한국방재학회 2018 한국방재학회논문집 Vol.18 No.2

본 연구에서는 다기준의사결정기법인 프로메티(PROMETHEE) 기법과 가중치 산정기법인 엔트로피(Entropy) 기법을 적용하여 도시 중소유역의 홍수위험도를 평가하였다. 도시 중소유역의 홍수위험도 평가와 관련된 지표를 강우, 유출, 지역 요인에 따른 항목으로 구분하였다. 강우 요인으로는 경보강우량, 유출 요인으로 유출수문곡선의 상승부경사, 홍수량 비, 홍수지속시간을 선정하였으며, 지역 요인으로 불투수율, 첨두홍수 기여율, 단위면적당 기여량을 선정하였다. 이에 따라 도시 중소유역인 수영강 20개 소유역을 대상으로 홍수위험도와 가중치를 산정하고 6개, 14개, 6개의 고ㆍ중ㆍ저 홍수위험 구역으로 구분하고 적용성을 검토하였다. 고위험군에 해당하는 14번 소유역은 과거 집중호우로 피해가 발생한 지역으로 본 연구에서 제안한 평가기법이 적용성이 높은 것으로 확인되었다. This study has performed the relative flood risk assessment in the urban small watershed using entropy method and PROMETHEE (Preference Ranking Organizing METHod for Enrichment Evaluations) which is one of the multi criteria decision making method. The evaluation criteria are classified into three categories according to the rainfall and runoff characteristic and regional characteristic. Those are flood warning rainfall, rising curve gradient, flood magnitude ratio, flood duration time, flood contribution rate per unit area, impervious cover rate. Suyeong basin is separated to 20 subbasins and the suggested method is applied to verify its applicability. Out of twenty subbasins, six, fourteen and six basins are evaluated as high risk, medium risk and low risk. The flood occurred in one of high risk subbasins in the past and it is found that the method of this study is higher applicability.

BitLog2: 비트 시프트 연산을 이용한 어텐션 맵의 로그 기반 4 비트 양자화

이지호(Lee Jiho),강우철(Kang Woochul) 한국통신학회 2024 한국통신학회 학술대회논문집 Vol.2024 No.11

추정오차분석을 통한 최적 강우관측망 구축에 대한 연구

이지호(Lee, Jiho),전환돈(Jun, Hwandon) 한국방재학회 2017 한국방재학회논문집 Vol.17 No.1

본 연구에서는 경제적인 강우관측망 구축을 위해 대상유역의 강우관측망의 공간적 특성을 검토하고 면적평균강우량의 추정오차 분석을 통해 최적의 강우관측소 개수 및 위치를 결정하는 방안을 제안하고자 한다. 강우관측망의 공간적 특성은 최근린 지수를 이용하여 평가하였고, 면적평균강우량 산정방법으로는 산술평균법, 티센가중법, 추정이론을 적용하였다. 그 결과 강우관측소의 개수가 적지만 공간분포가 좋은 경우보다 강우관측소의 공간분포가 나쁘지만 개수가 많은 경우가 면적평균강우량의 산정에서 추정오차를 더 발생시켰다. 아울러 새로운 유역에 강우관측망을 구축시 강우관측망의 밀도와 강우관측소의 공간분포 둘 다 고려되어야 함을 확인하였다. 관리적⋅비용적 측면에서 볼 때 공간적 분포가 고려된 강우관측망은 강우관측소의 개수가 적어도 신뢰성 있는 강우자료의 획득이 가능함을 확인하였다. 아울러 대상유역의 경우 20개의 관측소 중 18개를 운영하더라도 현재 정확도를 유지할 수 있는 것으로 분석되었다. 따라서 본 연구에서 제시된 방법론은 최적강우관측망 구축에 있어 강우관측소 개수 결정 및 선정에 적용할 수 있다. To construct the efficient rain gauge network, we examine the spatial distribution characteristics of the rain gauge for study basin and propose the method to determine the optimal number of rain gauge and location by analyzing the estimation error of the AAR(Areal Average Rainfall). The spatial characteristic of the rain gauge network is evaluated by using the NNI(Nearest Neighbor Index), while the arithmetic mean method, Thiessen’s weighting method and the estimation theory are applied to calculate the AAR. As a result, even after re-establishing the rain gauge networks for the study basin, the well distributed networks produce a smaller estimation error compared to a clustered rain gauge network when calculating the AAR. When establishing a new rain gauge network in a watershed, both the density and the spatial distribution of the rain gauge stations must be taken into consideration. Considering the maintenance and financial aspect, it is found that the rain gauge networks with proper spatial distributions are able to obtain a more accurate AAR despite having less rain gauge stations, It is verified that it is possible to maintain the current accuracy level despite maintaining 18 out of 20 of the rain gauge stations. Therefore, the methods suggested in this study can be applied to establish a proper and efficient rain gauge network.

소방차용 더블캡 구조 보강을 위해 멤버가 추가된 Roof Bow 강도 해석 연구

이지호(Jiho Lee),김태호(Taeho Kim),양동욱(Donguk Yang),이용수(Yongsoo Lee) 한국자동차공학회 2024 한국자동차공학회 학술대회 및 전시회 Vol.2024 No.11

온·오프라인 언어재활 프로세스 지원을 위한 인공지능 기반 언어재활 플랫폼 개발

이지호(Jiho Lee),김나연(Nayeon Kim),구하연(Hayeon Ku),이준희(Junhee Lee),설영진(Youngjin Seol),윤장혁(Janghyeok Yoon),하지완(Jiwan Ha),박기수(Ki-Su Park) 한국언어치료학회 2024 한국언어치료학회 학술발표대회 논문집 Vol.2024 No.11