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Wave prediction in a port using a fully nonlinear Boussinesq wave model

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Acta Oceanologica Sinica 2019年第7期38卷 36-47页

作者： Young-Kwang choi Seung-Nam Seo Jin-Yong choi Fengyan Shi Kwang-Soon Park Civil and Architectural Engineering Department KEPCO Engineering and ConstructionGimcheon-si 39660Republic of Korea Task Force for Construction of RV ISABU Support Facility Korea Institute of Ocean Science and TechnologyBusan Metropolitan City 49111Republic of Korea Operational Oceanography Research Center Korea Institute of Ocean Science and TechnologyBusan Metropolitan City 49111Republic of Korea Center for Applied Coastal Research University of DelawareNewark DE 19716USA

A wave forecasting system using FUNWAVE-TVD which is based on the fully nonlinear Boussinesq equations by Chen(2006)was developed to provide an accurate wave prediction in the Port of Busan,South *** system is linked to the Korea Operational Oceanographic System(KOOS)developed by Park et al.(2015).The computational domain covers a region of 9.6 km×7.0 km with a grid size of 2 m in both directions,which is sufficient to resolve short waves and dominant sea *** total number of grid points exceeds 16 millions,making the model computational *** provide real-time forecasting,an interpolation method,which is based on pre-calculated results of FUNWAVE-TVD and SWAN forecasting results at the FUNWAVE-TVD offshore boundary,was used.A total of 45 cases were pre-calculated,which took 71 days on 924 computational cores of a Linux cluster *** wave generation and propagation from the deep water were computed using the SWAN in *** results provided a boundary condition for the FUNWAVE-TVD forecasting *** verify the model,wave observations were conducted at three locations inside the port in a time period of more than 7 months.A model/model comparison between FUNWAVE-TVD and SWAN was also carried *** is found that,FUNWAVE-TVD improves the forecasting results significantly compared to SWAN which underestimates wave heights in sheltered areas due to incorrect physical mechanism of wave diffraction,as well as large wave heights caused by wave reflections inside the port.

关键词： real-time wave forecasting FUNWAVE-TVD SWAN KOOS wave observations wave diffraction

Analysis and Modeling of Propagation in Tunnel at 3.7 and 28 GHz

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Computers, Materials & Continua 2022年第5期71卷 3127-3143页

作者： Md Abdus Samad Dong-You choi Department of Information and Communication Engineering Chosun UniversityGwangju61452Korea Department of Electronics and Telecommunication Engineering International Islamic University ChittagongChittagong4318Bangladesh

In present-day society,train tunnels are extensively used as a means of ***,to ensure safety,streamlined train operations,and uninterrupted internet access inside train tunnels,reliable wave propagation modeling is *** have experimented and measured wave propagation models in a 1674 m long straight train tunnel in South *** measured path loss and the received signal strength were modeled with the Close-In(CI),Floating intercept(FI),CI model with a frequency-weighted path loss exponent(CIF),and alpha-beta-gamma(ABG)models,where the model parameters were determined using minimum mean square error(MMSE)*** measured and the CI,FI,CIF,and ABG modelderived path loss was plotted in graphs,and the model closest to the measured path loss was identified through *** on the measured results,it was observed that every model had a comparatively lower(n<2)path loss exponent(PLE)inside the *** also determined the path loss component’s possible deviation(shadow factor)through a Gaussian distribution considering zero mean and standard deviation calculations of random error *** FI model outperformed all the examined models as it yielded a path loss closer to the measured datasets,as well as a minimum standard deviation of the shadow factor.

关键词： Path loss shadow factor telecommunications train tunnel wave propagation wireless networks

Establishment of a prediction tool for ocular trauma patients with machine learning algorithm

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International Journal of Ophthalmology(English edition) 2021年第12期14卷 1941-1949页

作者： Seungkwon choi Jungyul Park sungwho Park Iksoo Byon Hee-Young choi Department of Ophthalmology Pusan National University HospitalBusan 49241Republic of Korea Biomedical Research Institute of Pusan National University Hospital Busan 49241Republic of Korea Department of Ophthalmology School of MedicinePusan National UniversityBusan 49241Republic of Korea

AIM:To predict final visual acuity and analyze significant factors influencing open globe injury ***:Prediction models were built using a supervised classification algorithm from Microsoft Azure Machine Learning *** best algorithm was selected to analyze the predicted final visual *** retrospectively reviewed the data of 171 patients with open globe injury who visited the Pusan National University Hospital between January 2010 and July *** then applied cross-validation,the permutation feature importance method,and the synthetic minority over-sampling technique to enhance tool ***:The two-class boosted decision tree model showed the best predictive *** accuracy,precision,recall,F1 score,and area under the receiver operating characteristic curve were 0.925,0.962,0.833,0.893,and 0.971,*** increase the efficiency and efficacy of the prognostic tool,the top 14 features were finally selected using the permutation feature importance method:(listed in the order of importance)retinal detachment,location of laceration,initial visual acuity,iris damage,surgeon,past history,size of the scleral laceration,vitreous hemorrhage,trauma characteristics,age,corneal injury,primary diagnosis,wound location,and lid ***:Here we devise a highly accurate model to predict the final visual acuity of patients with open globe *** tool is useful and easily accessible to doctors and patients,reducing the socioeconomic *** further multicenter verification using larger datasets and external validation,we expect this model to become useful worldwide.

关键词： machine learning ocular trauma open globe injury predictive model vision preservation

Forest insect assemblages attracted to light trap on two high mountains(Mt. Jirisan and Mt. Hallasan) in South Korea

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Journal of Forestry Research 2016年第5期27卷 1203-1210页

作者： Pyae Pyae Thein Sei-Woong choi Department of Environmental Education Mokpo National University

Assemblages of forest insects across two high mountains （Mt. Hallasan： JJ and Mt. Jirisan： JR） in South Korea were compared by collecting insects using an ultraviolet light trap at 20 sites （200-1700 m elevation ranges） from May to October 2013. A total of 2960 individuals, representing 481 species of 10 orders, were collected on JJ, compared with 7080 individuals representing 769 species of 14 orders on JR. The estimated number of species on JJ was 667 compared with 952 on JR. The differentiation among habitats （[3-diversity） was higher on JJ （4.95） than JR （4.33） because of the island characteris- tics of JJ. Six insect orders （Lepidoptera, Coleoptera, Diptera, Hymenoptera, Hemiptera and Trichoptera） were dominant on both mountains, suggesting that the light trap captures represented well the insect fauna and is an effective method for investigating forest insect diversity. We concluded that forest insect assemblages on mountains are mainly affected by the elevation and the dominant forest in each elevation. In addition, the insect fauna on each mountain was differentiated by the habitat, which could be correlated with geological history.

关键词： Island Mainland Species richness Abundance - Nocturnal insects

Regular truss structure model equivalent to continuum structure

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International Journal of Agricultural and Biological Engineering 2015年第5期8卷 151-161页

作者： Won choi JeongJae Lee Seongsoo Yoon Department of Rural Systems Engineering College of Agriculture and Life SciencesSeoul National UniversitySeoul 151-921South Korea Department of Rural Systems Engineering Research Institute of Agriculture and Life SciencesCollege of Agriculture and Life SciencesSeoul National UniversitySeoul 151-921South Korea Department.of Agricultural and Rural Engineering College of AgricultureLife and Environments SciencesChungbuk National UniversityChungbuk 362-763South Korea

It is difficult to solve the structural problems related to agricultural engineering,due to the wide ranges of the means of related variables and complex structural *** these reasons,discrete models are required that are able to replace or simplify solid structure components used in traditional analysis ***,the objective of this study was to develop a regular truss structure model that behaves the same way as a solid *** was assumed that if a unit element consists of truss elements with each hinge at the end of the element and the size of the element is infinitesimal,the stress distribution and displacement field will be constant throughout the domain of the unit ***,the behavior of the truss element was assumed to be in a linear state in a two-dimensional *** law of energy conservation,based on the theory of elasticity,was applied to determine the equilibrium conditions between discretized and solid *** restrictive condition that we obtained revealed that applications are limited to only ideal elastic materials with a Poisson’s ratio of 1 to *** volumetric ratio of the equivalent truss to the continuum structures was 3:1,regardless of the size or number of the *** calculate the internal stress and strain of the unit element,the geometric relationships of each truss member,which has its own role against different stress directions,were *** calculated von Misses stresses were used to verify this *** concentrations,as explained based on Saint Venant’s principle,were also observed in the equivalent truss structure *** main stress paths,indicating the areas where reinforcement bars should be placed,were successfully shown without the requirement that each element be transformed in the direction of principal stress;this was done by eliminating elements with only compressive and near-zero stresses.

关键词： structural analysis regular mesh equivalent truss structure model discretized element energy method

The Betti Numbers of Real Toric Varieties Associated to Weyl Chambers of Type B

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Chinese Annals of Mathematics,Series B 2017年第6期38卷 1213-1222页

作者： Suyoung choi Boram PARK Hanchul PARK Department of Mathematics Ajou University School of Mathematics Korea Institute for Advanced Study

The authors compute the(rational) Betti number of real toric varieties associated to Weyl chambers of type B, and furthermore show that their integral cohomology is p-torsion free for all odd primes p.

关键词： Real toric variety Real toric manifold Betti number Torsion-free cohomology Root system Weyl chambers Type B Generalized Euler number Springernumber Shellability

Role of kaempferol to increase bioavailability and pharmacokinetics of nifedipine in rats

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Chinese Journal of Natural Medicines 2019年第9期17卷 690-697页

作者： PARK Ji-Won choi Jin-Seok Hazardous Substances Analysis Division Gwangju Regional Office of Food and Drug SafetyGwangju 61012Republic of Korea Department of Medical Management Chodang UniversityJeollanam-do 58530Republic of Korea

Herein,the purpose of this study is to evaluate the effects of kaempferol on bioavailability and pharmacokinetics of nifedipine and its metabolite dehydronifedipine in *** experimental design is based on with or without kaempferol in the oral and intravenous administration of nifedipine in ***,the pharmacokinetic parameters including nifedipine and dehydronifedipine were evaluated in *** in vitro studies of kaempferol were investigated on P-glycoprotein(P-gp)and cytochrome P450(CYP)3A4 *** reduced a 50%inhibitory concentration(IC50)of 8.6μmol·L-1 on CYP3A4 enzyme ***,kaempferol clearly improved the cell internalization of rhodamine-123 in MCF-7/ADR cells overexpressing *** on increased concentrations of kaempferol,the areas under the plasma concentration–time curve(AUC0-∞)and the peak concentration(Cmax)of nifedipine were increased after oral and intravenous ***,the absolute bioavailability(AB)and relative bioavailability(RB)of nifedipine in the presence of kaempferol was significantly higher than those of the control group after oral and intravenous *** of bioavailability of nifedipine by kaempferol may be mainly because of the inhibition of the P-gp-mediated efflux transporter in the small intestine and CYP3A4-mediated metabolism in the small intestine or liver,or both.

关键词： Nifedipine Kaempferol CYP3A4 P-gp Pharmacokinetics Bioavailability

Time-domain channel estimator based on cyclic correlationfor OFDM systems with guard interval

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The Journal of China Universities of Posts and Telecommunications 2008年第2期15卷 26-31页

作者： IM Se-bin choi Hyung-jin Communication Research Center Harbin Institute of Technology

Channel impulse response （CIR） can be estimated on the basis of cyclic correlation in time-domain for orthogonal frequency division multiplexing （OFDM） systems, This article proposes a generalized channel estimation method to reduce the estimation error by taking the average of different CIRs. Channel impulse responses are derived according to the different starting points of cyclic correlation. In addition, an effective CIR length estimation algorithm is also presented. The whole proposed methods are more effective to OFDM systems, especialiy to those with longer cyclic prefix. The analysis and the simulation results verify that the mean square error performance is 4-5 dB better than the conventional schemes under the same conditions.

关键词： CIR OFDM channel estimation mean squareerror (MSE)

ON THE ASYMPTOTIC DYNAMICS OF THE VLASOV-YUKAWA-BOLTZMANN SYSTEM NEAR VACUUM

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Acta Mathematica Scientia 2015年第4期35卷 887-905页

作者： Sun-Ho choi Seung-Yeal HA Department of Mathematical Sciences KAIST Department of Mathematical Sciences and Research Institute of Mathematics Seoul National University

In this pape,~ we study uniform L1-stability and asymptotic completeness of the Vlasov-Yukawa-Boltzmann （V-Y-B） system. For a sufficiently small rand smooth initial data, we show that classical solutions exist globally and satisfy dispersion estimates, uniform L1-stability with respect to initial data and scattering type estimate. We show that the short range nature of interactions due to the Yukawa potential enables us to construct robust Lyapunov type functional to derive scattering states. In the zero mass limit of force carrier particles, we also show that the classical solutions to the V-Y-B system converge to that of the Vlasov-Poisson-Boltzmann （V-P-B） system in any finite time interval

关键词： asymptotic completeness collision operator the Vlasov-Yukawa-Boltzmannsystem uniform L1-stability