M2 Tidal Current Estimation from One-day Observation Data off the Western and Southern Coasts of Korea     

Lee  Seok  Oh  Kyung-Hee  Jang  Sung-Tae  You  Hak Yoel  Park  Joonsung  Song  Kyu-Min 《Ocean Science Journal》2019,54(1):39-50

Ocean Science Journal - A practical method to estimate the M2 tidal current is proposed based on one-day current observations. In this method, the semi-diurnal constituent, composed of several...  相似文献   

Evaluation of typhoon‐induced rainfall using nonparametric Monte Carlo simulation and locally weighted polynomial regression     

Tae‐Suk Oh  Young‐Il Moon  Hyun‐Han Kwon 《水文研究》2011,25(11):1765-1777

Typhoons in Korea are the major causes of natural disasters in the Korean peninsula. In this study, rainfall generated by typhoons was quantitatively analysed using various statistical methods. First, the frequency analysis of rainfall induced by typhoons was carried out to calculate the design rainfall. Second, the frequency analysis of simulated rainfall derived by nonparametric Monte Carlo simulation (NMCS) was performed to evaluate the uncertainty of rainfall caused by typhoons. Third, the regression relationship between the physical characteristic factors of typhoons and rainfall was established by locally weighted polynomial regression (LWPR), and the characteristic factors of typhoons were simulated. The simulated characteristic factors were then used to estimate rainfall and to calculate the design rainfall by typhoons. Comparative analyses of design rainfalls as estimated using various statistical methods were performed. The LWPR showed good performance in terms of reproducing typhoon characteristics. Therefore, the combined NMCS and LWPR method suggested in this study can be used as a supplementary technique for assessing extreme rainfall with climate change and reflected variability. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

The value of updating ensemble streamflow prediction in reservoir operations     

Hyung‐Il Eum  Young‐Oh Kim 《水文研究》2010,24(20):2888-2899

This study proposes a new monthly ensemble streamflow prediction (ESP) forecasting system that can update the ESP in the middle of a month to reflect the meteorological and hydrological variations during that month. The reservoir operating policies derived from a sampling stochastic dynamic programming model using ESP scenarios updated three times a month were applied to the Geum River basin to measure the value of updated ESP for 21 years with 100 initial storage combinations. The results clearly demonstrate that updating the ESP scenario improves the accuracy of the forecasts and consequently their operational benefit. This study also proves that the accuracy of the ESP scenario, particularly when high flows occur, has a considerable effect on the reservoir operations. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Valuing visitors' economic benefits of public beach access points     

Chi-Ok Oh  Anthony W. Dixon  James W. Mjelde  Jason Draper 《Ocean & Coastal Management》2008,51(12):847-853

An increase in the population of coastal counties and popularity of coastal beaches as tourism destinations create difficulties for management agencies responsible for providing public beach access. The objective of this paper is to determine non-resident visitors to South Carolina beaches economic value for public beach access. Visitors are willing to pay an extra $6.60 per day for additional beach access points and parking or an aggregate of $93 million. Visitors' economic value of public beach access allows decision-makers the ability to better compare management policies in their efforts to provide sufficient public beach access through a target effective strategy.  相似文献   

Thermodynamic characteristics and responses to ENSO of dominant intraseasonal modes in the East Asian summer monsoon     

Hyoeun Oh  Kyung-Ja Ha 《Climate Dynamics》2015,44(7-8):1751-1766

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Evaluation of building period formulas for seismic design     

Oh‐Sung Kwon  Eung Soo Kim 《地震工程与结构动力学》2010,39(14):1569-1583

Building period formulas in seismic design code are evaluated with over 800 apparent building periods from 191 building stations and 67 earthquake events. The evaluation is carried out with the formulas in ASCE 7‐05 for steel and RC moment‐resisting frames, shear wall buildings, braced frames, and other structural types. Qualitative comparison of measured periods and periods calculated from the code formulas shows that the formula for steel moment‐resisting frames generally predicts well the lower bound of the measured periods for all building heights. But the differences between the periods from code formula and measured periods of low‐ to‐medium rise buildings are relatively high. In addition, the periods of essential buildings designed with the importance factor are about 40% shorter than the periods of non‐essential buildings. The code formula for RC moment‐resisting frames describes well the lower bound of measured periods. The formula for braced frames accurately predicts the lower bound periods of low‐to‐medium rise buildings. The formula for shear wall buildings overestimates periods for all building heights. For buildings that are classified as other structural types, the measured building periods can be much shorter than the periods calculated with the code formula. Based on these observations, it is suggested to use C_r factor of 0.015 for shear walls and other structural types. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Dissolved organic phosphorus utilization and alkaline phosphatase activity of the dinoflagellate <Emphasis Type="Italic">Gymnodinium impudicum</Emphasis> isolated from the South Sea of Korea     

Seok Jin Oh  Hyeong Kyu Kwon  Il Hyeon Noh  Han-Soeb Yang 《Ocean Science Journal》2010,45(3):171-178

This study investigated alkaline phosphatase (APase) activity and dissolved organic and inorganic phosphorus utilization by the harmful dinoflagellate Gymnodinium impudicum (Fraga et Bravo) Hansen et Moestrup isolated from the South Sea of Korea. Under conditions of limited phosphorus, observation of growth kinetics in batch culture yielded a maximum growth rate (μ_max) of 0.41 /day and a half saturation constant (Ks) of 0.71 μM. In time-course experiments, APase was induced as dissolved inorganic phosphorus (DIP) concentrations fell below 0.83 μM, a threshold near the estimated Ks; APase activity increased with further DIP depletion to a maximum of 0.70 pmol/cell/h in the senescent phase. Thus, Ks may be an important index of the threshold DIP concentration for APase induction. G. impudicum utilizes a wide variety of dissolved organic phosphorus compounds in addition to DIP. These results suggest that DIP limitation in the Southern Sea of Korea may have led to the spread of G. impudicum along with the harmful dinoflagellate Cochlodinium polykrikoides in recent years.  相似文献   

The evolution of the Lyα forest effective optical depth following He ii reionization     

James S. Bolton  S. Peng Oh  Steven R. Furlanetto 《Monthly notices of the Royal Astronomical Society》2009,396(4):2405-2418

Three independent observational studies have now detected a narrow  (Δ z ≃ 0.5)  dip centred at   z = 3.2  in the otherwise smooth redshift evolution of the Lyα forest effective optical depth. This feature has previously been interpreted as an indirect signature of rapid photoheating in the intergalactic medium (IGM) during the epoch of He  ii reionization. We examine this interpretation using a semi-analytic model of inhomogeneous He  ii reionization and high-resolution hydrodynamical simulations of the Lyα forest. We instead find that a rapid  (Δ z ≃ 0.2)  boost to the IGM temperature  (Δ T ≃ 10⁴ K)  beginning at   z = 3.4  produces a well understood and generic evolution in the Lyα effective optical depth, where a sudden reduction in the opacity is followed by a gradual, monotonic recovery driven largely by adiabatic cooling in the low-density IGM. This behaviour is inconsistent with the narrow feature in the observational data. If photoheating during He  ii reionization is instead extended over several redshift units, as recent theoretical studies suggest, then the Lyα opacity will evolve smoothly with redshift. We conclude that the sharp dip observed in the Lyα forest effective optical depth is instead most likely due to a narrow peak in the hydrogen photoionization rate around   z = 3.2  , and suggest that it may arise from the modulation of either reprocessed radiation during He  ii reionization, or the opacity of Lyman limit systems.  相似文献   

Effects of Resonances in Corrugated Horn Antennas for a 22-GHz Balancing Radiometer     

DeWachter  E. Murk  A. Straub  C. Haefele  A. Soohyun Ka Jung Jin Oh Kampfer  N. 《Geoscience and Remote Sensing Letters, IEEE》2009,6(1):3-7

The Stratospheric WAter vapor RAdiometer (SWARA) is a microwave radiometer designed for ground-based measurements of water vapor (H₂O) in the middle atmosphere (20 to 80 km), including the stratosphere and mesosphere. The instrument is operating in a noncryogenic balancing calibration mode. Since its deployment, features have been observed in the spectrum which can be attributed to resonant variations of the antenna pattern of the corrugated horn. This paper presents copolar and crosspolar antenna pattern measurements of two sister antennas of the SWARA horn, as well as water vapor measurements from both antennas on the ground-based microwave radiometer MI ddle Atmospheric WAter vapor RA diometer. We show that small irregularities in the frequency spectrum at the -20-dB level are visible in the copolar pattern, which, due to the balancing operation scheme used for the radiometer, lead to features in the spectrum that have the same or even higher brightness temperature as the line of interest.  相似文献   

Development of the AUV ‘ISiMI’ and a free running test in an Ocean Engineering Basin     

Bong-Huan Jun  Jin-Yeong Park  Pan-Mook Lee  Kihun Kim  Jun-Ho Oh 《Ocean Engineering》2009,36(1):2-14

The Korea Ocean Research and Development Institute (KORDI) has developed a small AUV named ISiMI. The mission of ISiMI is to work as a test-bed AUV for the development and validation of various algorithms and instruments required to enhance the AUV's functions. The design concept of ISiMI is that of a vehicle small enough to cruise the Ocean Engineering Basin (OEB) of KORDI and to be handled by one or two people. The downsized design and the cruising ability in its tank enable fast experimental feedback on AUV technologies and a shorter development period for new technologies. This paper presents a review of our research work on the development of ISiMI, with a performance evaluation by simulation and an experimental test. After the design and implementation of ISiMI, including its positioning system in the OEB, are presented, a series of test results in the OEB and discussions of the results are presented, with comparisons of the simulation and experimental outputs.  相似文献