Comparative analysis of four stem taper models for Quercus glauca in Mount Halla,Jeju Island,South Korea     

LUMBRES Roscinto Ian Canicosa  LEE Young Jin  CHOI Hyung Soon  KIM Sung Yong  JANG Mi Na  ABINO Azyleah Caizares  SEO Yeon Ok  KIM Chan Soo  PARK Jung Hwan 《山地科学学报》2014,11(2):442-448

This study was conducted to fit the diameter-height data of Quercusglaucain Jeju Island, South Korea to the four commonly used stem taper equations andto evaluate the performance of the four stem taper models using four statistical criteria： Fit index （FI）, root mean square error （RMSE）, bias （）,and absolute mean difference （AMD）. Results showed that the Kozak02stem taper equation provided the best FI（0.9847）, RMSE（1.5745）,（-0.0030 cm） and AMD （1.0990 cm） whileMax and Burkhart model had the poorest performance among the four stem taper models based on the four evaluation statistics （FI ： 0.9793,RMSE ： 1.8272, ： 0.3040 cm and AMD ： 1.3060 cm）. These stem taper equations can serve as a useful tool for forest managers in estimating the diameter outside bark at any given height, merchantable stem volumes and total stem volumesof the standing trees of Quercusglaucain theGotjawal forests located in Mount Halla, Jeju Island, South Korea.  相似文献   

Sediment reworking by a polychaete, <Emphasis Type="Italic">Perinereis aibuhitensis</Emphasis>, in the intertidal sediments of the Gomso Bay,Korea     

Bon Joo Koo  Jaehwan Seo 《Ocean Science Journal》2017,52(4):511-518

Bioturbation, especially sediment reworking by the activities of macroinvertebrates, such as feeding and burrowing, is one of the major processes that affect the physical, chemical, and biological characteristics of marine sediments. Given the importance of sediment reworking, this study was designed to evaluate the sediment reworking rate of a polychaete, Perinereis aibuhitensis, which is dominant in the upper tidal flats on the west coast of Korea, based on quantification of pellet production during spring and fall surveys. The density of individuals was higher in fall than in spring, whereas, due to a difference in the proportion of adults between the two seasons, the morphometric dimensions of the worm and its pellets were significantly longer and heavier in the spring. Hourly pellet production per inhabitant and density were closely related, with pellet production gradually decreasing as density increased. Daily pellet production was much higher in spring than in fall, mostly due to an increase in daytime production. The sediment reworking rate of Perinereis was similar in the two seasons in which observations were made and depended on its density and the sediment reworking rate per individual. The overall sediment reworking rate of Perinereis was 31 mm yr^?1 based on its density in the study area.  相似文献   

Hammer Efficiency and Correction Factors for the TxDOT Texas Cone Penetration Test     

Rozbeh B. Moghaddam  William D. Lawson  James G. Surles  Hoyoung Seo  Priyantha W. Jayawickrama 《Geotechnical and Geological Engineering》2017,35(5):2147-2162

This study analyzes blowcount data from instrumented Texas Cone Penetration (TCP) tests. TCP hammer efficiency, rod length influence on the hammer efficiency, and overburden pressure correction factors for the TCP blowcounts (N_TCP) are explored. Results are compared to published correction factors for the standard penetration test (SPT). The final dataset analyzed for this study consisted of 293 TCP tests from which 135 tests were instrumented. TCP hammer efficiency values for automatic trip hammers ranged from 74 to 101% with an average of 89%. Analyses showed a statistically-significant relationship between the TCP hammer efficiency and the rod length below ground surface. Statistical models were developed for undifferentiated soils, and corresponding rod length correction factors for the TCP test (C_R-TCP) were obtained ranging from 0.90 to 1.00. In a second analysis, the relationship between the overburden pressure and N_TCP was explored and a mathematical expression for the overburden correction factor for the TCP blowcount value (C_N-TCP) was determined. This work represents the first study where corrections to N_TCP are explored, and the outcome of this research benefits the geotechnical engineering community using the TCP test and its associated foundation design method.  相似文献   

Storm surge prediction using an artificial neural network model and cluster analysis   总被引：1，自引：1，他引：0  

Sung Hyup You  Jang-Won Seo 《Natural Hazards》2009,51(1):97-114

In this study, an artificial neural network model was developed to predict storm surges in all Korean coastal regions, with a particular focus on regional extension. The cluster neural network model (CL-NN) assessed each cluster using a cluster analysis methodology. Agglomerative clustering was used to determine the optimal clustering of 21 stations, based on a centroid-linkage method of hierarchical clustering. Finally, CL-NN was used to predict storm surges in cluster regions. In order to validate model results, sea levels predicted by the CL-NN model were compared with results using conventional harmonic analysis and the artificial neural network model in each region (NN). The values predicted by the NN and CL-NN models were closer to observed data than values predicted using harmonic analysis. Data such as root mean square error and correlation coefficient varied only slightly between CL-NN and NN model results. These findings demonstrate that cluster analysis and the CL-NN model can be used to predict regional storm surges and may be used to develop a forecast system.  相似文献   

Physicochemical characteristics for adsorption of MTBE and cadmium on clay minerals     

Joo-Hyun Sim  Hyung-Joon Seo  Chang-Gyun Kim 《Environmental Earth Sciences》2009,59(3):537-545

Physicochemical characteristics relevant to the adsorption of MTBE and Cd on three types of clay minerals were investigated. The characteristics were examined through batch adsorption tests conducted under various experimental conditions such as adsorption time, ratio of solution-to soil, concentration of solutes, concentration of organic matters, pH, and zeta potential. The adsorption efficiency of MTBE or Cd on three types of clays decreased in response to an increase of the ratio of solution-to-soil; nevertheless, the adsorbed amounts inversely increased. MTBE was adsorbed on clays in an increasing order of vermiculite, bentonite, and CTAB-bentonite. However, Cd was adsorbed in a different order of bentonite, vermiculite, and CTAB-bentonite. The adsorption of MTBE was well fitted with the Freundlich model, whereas the Cd was more closely suited to a Langmuir equation. By adding humic acids of 1 and 5%, MTBE was significantly adsorbed on bentonite and vermiculite, respectively, but beyond that, its adsorption was diminished. In comparison, the adsorption on CTAB-bentonite was increased in proportion to the humic acids addition. Likewise, the addition of humic acids acted to increase the adsorption of Cd regardless of the types of adsorbent, where up to 90% of Cd was removed at pH 10. Further increase of pH declined the degree of zeta potential, while increasing Cd concentration also lowered the zeta potential, which consequently contributes in enhancing the adsorption efficiency of Cd on clays.  相似文献   

Wave prediction in a port using a fully nonlinear Boussinesq wave model   总被引：1，自引：0，他引：1  

Choi Young-Kwang  Seo Seung-Nam  Choi Jin-Yong  Shi Fengyan  Park Kwang-Soon 《海洋学报(英文版)》2019,38(7):36-47

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 Korea. This 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 states. The total number of grid points exceeds 16 millions,making the model computational expensive. To 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 system. Wind wave generation and propagation from the deep water were computed using the SWAN in KOOS. SWAN results provided a boundary condition for the FUNWAVE-TVD forecasting system. To 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 out. It 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.  相似文献   

Hydrological modelling uncertainty analysis for different flow quantiles: a case study in two hydro-geographically different watersheds   总被引：2，自引：2，他引：0  

Getachew Tegegne  Young-Oh Kim  Seung Beom Seo  Youngil Kim 《水文科学杂志》2019,64(4):473-489

This study focuses on analysis of hydrological model parameter uncertainty at varying sub-basin spatial scales. It was found that the variation in sub-basin spatial scale had little influence on the entire flow simulations. However, the different sub-basin spatial scales had a significant impact on the reproduction of the flow quantiles. The coarser sub-basin spatial scale provided a better coverage of most prediction uncertainty in observations. However, the finer sub-basin spatial scale produced the best single simulation output closer to the observations. In general, the optimal sub-basin spatial scales (ratio to the entire watershed size) in the two test watersheds were found to be in the ranges 14–19% and 2–4% for good simulation of high and low flows, respectively. It is therefore worthwhile to put more effort into reproducing different flow quantiles by investigating an appropriate sub-basin spatial scale.  相似文献   

Methods for ultimate limit state assessment of ships and ship-shaped offshore structures: Part I—Unstiffened plates     

Jeom Kee Paik  Bong Ju Kim  Jung Kwan Seo 《Ocean Engineering》2008,35(2):261-270

The present paper is Part I of a series of three papers prepared by the authors on the methods useful for ultimate limit state assessment of marine structures, that have been developed in the literature during the last few decades. It is considered that such methods are now mature enough to enter day-by-day design and strength assessment practice. The aims of the three papers are to conduct some benchmark studies of such methods on ultimate limit state assessment of (unstiffened) plates, stiffened panels, and hull girders of ships and ship-shaped offshore structures, using some candidate methods such as ANSYS nonlinear finite element analysis (FEA), DNV PULS, ALPS/ULSAP, ALPS/HULL, and IACS common structural rules (CSR) methods. As an illustrative example, an AFRAMAX-class hypothetical double hull oil tanker structure designed by CSR method is studied. In the present paper (Part I), the ultimate limit state assessment of unstiffened plates under combined biaxial compression and lateral pressure loads is emphasized using ANSYS, DNV PULS, and ALPS/ULSAP methods, and their resulting computations are compared. Part II will deal with methods for the ultimate limit state assessment of stiffened panels under combined biaxial compression and lateral pressure using ANSYS, DNV PULS, and ALPS/ULSAP methods, and Part III will treat methods for the progressive collapse analysis of the hull structure using ANSYS, ALPS/HULL, and IACS CSR methods.  相似文献   

Rapid and Accurate Method for Determining 234Th in Seawater: Fe Co-precipitation,UTEVA Extraction,and Micro-precipitation     

Seo  Junhyeong  Seo  Hojong  Hwang  Jeomshik  Kim  Guebuem 《Ocean Science Journal》2021,56(4):378-384

Ocean Science Journal - Thorium-234 (234Th; t1/2 = 24.1&nbsp;days) has been widely used as a tracer of particle settling and organic carbon export in the ocean. However, the use of...  相似文献   

Synthetic high-resolution near-IR spectra of the Sun for planetary data reductions made from ATMOS/Spacelab-3 and Atlas-3 data     

Haingja Seo  Sungwon Hwang  Aeran Jung  Ji Hyun Kim  Joo Hyeon Kim  Kap-Sung Kim  Jinny Lee  Minhwan Jang 《Icarus》2007,192(1):287-295

We have constructed synthetic solar spectra for the 2302-4800 cm⁻¹ (2.08-4.34 μm) range, a spectral range where planetary objects mainly emit reflected sunlight, using ATMOS (Atmospheric Trace Molecule Spectroscopy)/Spacelab-3 and Atlas-3 spectra, of which resolution is 0.01 cm⁻¹. We adopted Voigt line profiles for the modeling of line shapes based on an atlas of line identifications compiled by Geller [Geller, M., 1992. Key to Identification of Solar Features. A High-Resolution Atlas of the Infrared Spectrum of the Sun and the Earth Atmosphere from Space. NASA Reference Publ. 1224, vol. III. NASA, Washington, DC, pp. 1-22], who derived solar line positions and intensities from contaminated high-resolution solar spectra obtained by ATMOS/Spacelab-3. Because the ATMOS spectra in these wavelength ranges are compromised by absorption lines of molecules existing in Earth's high-altitude atmosphere and in the compartment of the spacecraft, the direct use of these high-resolution solar spectra has been inconvenient for the data reductions of planetary spectra. We compared the synthetic solar spectra with the ATMOS spectra, and obtained satisfactory fits for the majority of the solar lines with the exception of abnormal lines, which do not fit with Voigt line profiles. From the model fits, we were able to determine Voigt line parameters for the majority of solar lines; and we made a list of the abnormal lines. We also constructed telluric-line-free solar spectra by manually eliminating telluric lines from the ATMOS spectra and filling the gaps with adjacent continua. These synthetic solar spectra will be useful to eliminate solar continua from spectra of planetary objects to extract their own intrinsic spectral features.  相似文献