• East Asian mathematical journal
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• 제37권5호
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• pp.591-598
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• 2021

In this paper we study the Cauchy problem for the Chern-Simons gauged O(3) sigma model. We prove the local existence of solutions with low regularity initial data, observing null forms of the system and applying bilinear estimates for wave-Sobolev space H^{s, b}.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.217-217
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• 2015

The objective of this study was mainly to evaluate the water resources potential of Lake Tana Basin (LTB) by using Soil and Water Assessment Tool (SWAT). From SWAT simulation of LTB, about 5236 km2 area of LTB is gauged watershed and the remaining 9878 km2 area is ungauged watershed. For calibration of model parameters, four gauged stations were considered namely: Gilgel Abay, Gummera, Rib, and Megech. The SWAT-CUP built-in techniques, particle swarm optimization (PSO) and generalized likelihood uncertainty estimation (GLUE) method was used for calibration of model parameters and PSO method were selected for the study based on its performance results in four gauging stations. However the level of sensitivity of flow parameters differ from catchment to catchment, the curve number (CN2) has been found the most sensitive parameters in all gauged catchments. To facilitate the transfer of data from gauged catchments to ungauged catchments, clustering of hydrologic response units (HRUs) were done based on physical similarity measured between gauged and ungauged catchment attributes. From SWAT land use/ soil use/slope reclassification of LTB, a total of 142 HRUs were identified and these HRUs are clustered in to 39 similar hydrologic groups. In order to transfer the optimized model parameters from gauged to ungauged catchments based on these clustered hydrologic groups, this study evaluates three parameter transfer schemes: parameters transfer based on homogeneous regions (PT-I), parameter transfer based on global averaging (PT-II), and parameter transfer by considering Gilgel Abay catchment as a representative catchment (PT-III) since its model performance values are better than the other three gauged catchments. The performance of these parameter transfer approach was evaluated based on values of Nash-Sutcliffe efficiency (NSE) and coefficient of determination (R2). The computed NSE values was found to be 0.71, 0.58, and 0.31 for PT-I, PT-II and PT-III respectively and the computed R2 values was found to be 0.93, 0.82, and 0.95 for PT-I, PT-II, and PT-III respectively. Based on the performance evaluation criteria, PT-I were selected for modelling ungauged catchments by transferring optimized model parameters from gauged catchment. From the model result, yearly average stream flow for all homogeneous regions was found 29.54 m3/s, 112.92 m3/s, and 130.10 m3/s for time period (1989 - 2005) for region-I, region-II, and region-III respectively.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.781-786
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• 2009

The thesis shows that we gauged vibration of vehicular load regarding WPC girder bridge and researched into dynamic characteristics(natural frequency, vibration acceleration) of WPC girder bridge. By the basic of that, we researched on vibration serviceability by looking over and being compared to vibration criteria we had before. In the thesis, the gauged vibration made an analysis of vertical acceleration through FFT method and evaluated vibration serviceability about vibration sense the body feels by means of the standard of ISO assessment standard and Meister assessment standard by referring to analysis data. This research on bridge is WPC girder bridge of 90m span, width of 5.5m, and the experiment was gauged by a fluent which is right way and inverse way about dump truck of gross 270kN. Acceleration was located in the middle of 1st span, 2nd span, 3rd span. As a result of appraisal standard of Meister, the vibrations of the bridge have distributed between "Level C, Strongly Perceptible" and "Level B, Disturbing". Also the vibration can be attacked with unpleasant feeling. As a result of appraisal standard of ISO, from vibration influence didn't come to 60s, and reduced comfort boundary in part of most rigorous standard that such a case didn't happen.

• 한국소음진동공학회논문집
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• 제20권4호
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• pp.331-337
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• 2010

The thesis shows that we gauged vibration of vehicular load regarding WPC girder bridge and researched into dynamic characteristics(natural frequency, vibration acceleration) of WPC girder bridge. By the basic of that, we researched on vibration serviceability by looking over and being compared to vibration criteria we had before. In the thesis, the gauged vibration made an analysis of vertical acceleration through FFT method and evaluated vibration serviceability about vibration sense the body feels by means of the standard of ISO assessment standard and Meister assessment standard by referring to analysis data. This research on bridge is WPC girder bridge of 90 m span, width of 5.5 m, and the experiment was gauged by a fluent which is right way and inverse way about dump truck of gross 270 kN. Acceleration was located in the middle of 1st span, 2nd span, 3rd span. As a result of appraisal standard of Meister, the vibrations of the bridge have distributed between "level C, strongly perceptible" and "level B, disturbing". Also the vibration can be attacked with unpleasant feeling. As a result of appraisal standard of ISO, from vibration influence didn't come to 60s, and reduced comfort boundary in part of most rigorous standard that such a case didn't happen.

• 한국물환경학회지
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• 제35권6호
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• pp.481-496
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• 2019

The Ministry of Environment has measured streamflow at eight-day intervals for the estimation of standard flow of the Total Maximum Daily Loads (TMDL) system. This study identified the availability of the partially measured the eight-day interval data for estimating standard flow and found the optimal extension techniques of standard flow. The study area was selected for the Nakbon-A watershed in the Nakdong River, and four streamflow record extension techniques of standard flow were considered: extension, percentile, drainagearea, and regional regression methods. The flow duration curve (FDC) using the eight-day interval streamflow data indicated very high Nash and Sutcliffe Efficiency (NSE) values above 90 % from FDC-II to FDC-VII compared to FDC-VIII, the standard FDC. This result demonstrates that FDC using daily data of three-six cumulative years could represent standard FDC fairly well. For the streamflow record extension techniques of standard flow, the percentile method was selected as the optimal alternative, showing the minimal difference from FDC-VIII. These results validate the availability of the eight-day interval streamflow data in the standard flow estimation and the application of extension techniques. It seems that these results could reduce the uncertainty of partially measured streamflow data for water quantity and quality management.

• 한국물환경학회지
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• 제26권3호
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• pp.532-539
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• 2010

The synthetic unit hydrograph is developed and verified using Nash model and characteristic velocities considering geomorphological dispersion in this present study. Application watersheds are selected 5 subwatersheds of Bocheong basin. The mean and variance of hillslope and stream path length are estimated in each watershed with GIS. Characteristic velocities are calculated using estimated path lengths and moment characteristics of rainfall-runoff data. Characteristic velocities of random devised 7 ungauged watersheds are estimated through regional analysis of chracteristic velocities in guaged watershed. And Nash model parameters and IUH are derived using characteristic velocities and path length in the gauged and ungauged watershed. The result to compare of IUH about gauged watershed and random devised ungauged watershed in application watershed presents coherently hydrologic response characteristics that peak discharge is reduced and peak time is extended. In conclusion, Developed synthetic unit hydrograph in this study expects that it is useful method to estimate runoff discharge for managing of water pollution in ungauged watershed.

• 한국농공학회논문집
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• 제48권5호
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• pp.29-38
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• 2006

Geographic Information System has extended to higher assessment of water resources. GIS linking with hydrological model becomes a trend in water resource assessment modeling. One of the most popular models is SWAT2000 which have effectiveness in multi-purpose processes for predicting the impact of land management practices on water, sediments and chemicals yields in large complex watershed with varying soils, land uses, and management conditions over long period of time. In this study, SWAT2000 model was applied to Gap stream watershed in Daejeon city where TMDL (Total Maximum Daily Load) Regulation would be implanted. The Gap Stream watershed was partitioned into 8 subbasins, however, only 3 out of 8 subbaisns were observed for having practical gauged data on the basis of streamflow from the year of 2002 to 2005. Gauged streamflow data of Indong, Boksu and Hoeduck stations were used for calibration and validation of the SWAT Streamflow simulation. Estimation Efficiency Analysis (COE), Regression Analysis ($R^{2}$), Relative Error (R.E.) were used for comparing observed streamflow data of the 3 subbasins on the daily and monthly basis with estimated streamflow data in order to fix optimized parameters for the best fitted results. COE value for the daily and monthly streamflow was ranged from 0.45 to 0.96. $R^{2}$ values for daily and monthly streamflow ranged from 0.51 to 0.97. R.E. values for total streamflow volume ranged from 3 % to 22.5 %. The accuracy of the model results shows that the SWAT2000 model can be applicable to Korean watersheds like the Gap Stream watershed that needs to be partitioned into a number of subbasins for TMDL regulation.

• 한국수자원학회논문집
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• 제56권9호
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• pp.563-574
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• 2023

최근 기후변화로 인해 유역의 기상자료에 대한 반응이 달라지고 있어 강우-유출 모의에 대한 연구는 중요해지고 있다. 아울러 최근 기계학습 기법에 대한 높은 관심으로 이를 통한 강우-유출 모의 역시 활발하게 증가하고 있으나 기계학습 모형이 전통적으로 사용되어온 개념적 모형에 비해 활용성이 높은지는 아직 확실치 않다. 본 연구에서는 개념적 모형인 GR6J와 기계학습 모형인 Random Forest 성능을 한국 전역의 38개 계측 유역에 대해 계측 유역 예측기법과 미계측 유역 예측기법을 이용해 평가하였다. 먼저 계측 유역 적용기법 평가를 위해 각 모형을 관측 일 유량자료에 학습시키고 분리된 평가기간에 대한 모의성능을 비교하였다. 이후 미계측 유역 모의성능 평가를 위해 인접성 기반 지역화 방법을 Leave-One-Out Cross-Validation (LOOCV)을 이용해 평가하였다. 그 결과 계측 유역 평가에서는 Random Forest 기법이 GR6J 모형보다 일관되게 높은 성능을 보였다. 학습된 데이터를 출력 값으로 재생산하도록 구조화되어 있는 기계학습 기법이 개념적 이론을 통한 모형보다 높은 재현성을 갖기 때문으로 판단된다. 하지만 Random Forest 모형의 성능은 미계측 유역의 예측기법으로는 재현되지 않았고 GR6J 모형보다 성능이 더 낮은 것이 확인되었다. 본 연구는 기계학습 모형은 계측 유역의 유출예측에는 적용성이 높을 수 있으나 미계측 유역에 대한 적용가능성은 전통적인 개념적 모형보다 낮을 수 있음을 제시한다.

• 대한한의진단학회지
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• 제17권1호
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• pp.17-28
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• 2013

Objectives A descriptive, comparative study was performed using female college students as experimental subjects. The objective was to compare the pulse waves of experimental subjects having severe menstrual pain and control subjects having minor or no menstrual pain. Methods The subjects of this experiment were female college students and the data were collected from September 2011 to February 2012. During normalcy, these data were gauged a week to ten days after menstruation, and during menstruation, they were gauged two to three days after the start of menstruation, when the menstrual pain was at its peak. Results The results was as follows. 1. Right Chuk Ap of the menstrual period was significantly narrowed than usual period. In comparison of Ap on menstrual pain group and non menstrual pain group, Left Kwan Ap showed significant difference. 2. Left Chon $h_1$ and Right Chuk $h_1$ of the menstrual period was significantly lowered than usual period. Right Kwan $h_1$ was appeared significant difference between menstrual pain group and non menstrual pain group. 3. Left Chon Wm of the menstrual period was appeared significantly short than usual and left Kwan Wm of the menstrual period was appeared significantly long than usual. Conclusions Ap, $h_1$ and Wm of the menstrual period were changed in Qwan and Chuk. Ap, $h_1$ and Wm of the menstrual pain group were appeared significant difference than non menstrual pain group.

• 동의생리병리학회지
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• 제27권2호
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• pp.246-252
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• 2013

A descriptive, comparative study was performed using female college students as experimental subjects. The primary objective was to compare the changes in pulse waves that take place during normalcy and during menstruation. The second objective was to compare the pulse waves of experimental subjects with severe menstrual pain and experimental subjects with minor or no menstrual pain during menstruation and during normalcy. The subjects of this experiment were female college students attending D University, located in Pusan, and the data were collected from September 2011 to February 2012. Their blood circulation index and pulse-wave factors were measured. During normalcy, these data were gauged a week to ten days after menstruation, and during menstruation, they were gauged two to three days after the start of menstruation, when the menstrual pain was at its peak. The results was as follows. In the characteristics of the blood circulation index, the index increased during menstruation, resulting in an increase in only the blood volume of the left ventricle. And the pulse energy of the left Chon, Kwan, Cheok and right Cheok were significantly higher during menstruation. Additionally, the average pulse energy in the left hand was distinctively lower in the menstrual group than in the normalcy group. There is a difference in blood pulse factors between normalcy and during menstruation, as well as a difference in blood pulse factors in experiment group without menstrual pain and experiment group with menstrual pain. These differences were particularly observed in the blood circulation index, pulse energy.