• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.3
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• pp.251-261
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• 2006

The purpose of this study is to quantitatively estimate the settling property for fine-cohesive sediments in Keum Estuary and to evaluate the spatial variation by analyzing and comparing the local and seasonal variation of the settling properties in Keum Estuary with that of the settling properties in the other sites. After the spatial variation of physico-chemical properties such grain size distribution, the percentage of organic contents, mineralogical composition etc is investigated through experiments and analyses, interrelation between the physico-chemical properties and settling velocities and effect that the physico-chemical properties have on the quantitative variation of settling velocities were also analyzed in this study. Experimental results of settling tests shows that settling velocities of Keum Estuary mud vary in the range of two orders of magnitude (from 0.01 to 1mm/sec) over the corresponding concentration range of 0.1 to 80 g/L, and a feature of settling velocity profile is quite different in quantity as compared to those of previous studies with mud of other regions: Saemankuem, Tampa Bay, Sevem Estuary and lake Okeechobee. However, their local and seasonal variabilities within Keum Estuary appear to be insignificant.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.18 no.1
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• pp.1-10
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• 1982

Diffusion processes in tidal swinging coastal waters are studied by releasing one hundred liters of Rhodamine B four times. Dye patches were formed from instantaneous point sources. The patches were sampled with a pump on a tracking boat, and samples were analyzed with fluorospectro-photometer. The patterns of patches were reconstructed and their characteristics were analyzed in terms of variance of concentration, area estimation, and decrease rate of peak concentration. In all of the four experiments, the dye patches were mos시 elongated to the direction of current axis. the elongation rate was 0.34 on the average. Apparent diffusivities were 620 to 3,000 cm super(2) /sec during initial period of 90 minutes. The variance increased by exp(0.047t) on the average, and peak concentration deceased by exp(-0.044t) on the average.

• 한국해양학회지
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• v.25 no.1
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• pp.8-20
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• 1990

A series of pore water data were obtained during the different time over one year period between October 1987 and October 1988, from a site on a muddy intertidal flat, located in the Kyeong-gi Bay, west coast of Korea, The results have revealed that the tidal flat is an environment of active nutrient the subface supplied by the overlying seawater is almost completely removed from the pore water at depth of about 10 cm below the sediment surface. The nutrients such as ammonium and phosphate are produced through this process and subsequently accumulated in the pore water forming steep gradients near the sediment surface. Below the main sulfate redirection zone, a secondary peak of dissolved sulfate was often observed. Greal seasonal variation of the pore water nutrient profiles was observed, which was particularly clear in their maximum concentration as well as in their concentration gradient. The rate constants of sulfate reduction and nutrient regeneration, estimated by using a diagenetic model (Berner, 1980), differ by an order of magnitude between the summer and winter seasons. The difference in sediment temperature may account for most of the calculated variation. The C:N:P ratio, calculated from the pore water nutrient gradients also exhibits a slight seasonal difference. The organic matter being decomposed by sulfate reduction appears to be depleted in depleted in nitrogen, compared to the average marine organic matter.

• Food Science and Preservation
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• v.13 no.2
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• pp.174-179
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• 2006

The objective of the study was to investigate the effect of steaming pressure (0.5, 1.0, and 1.5 bar), steaming time (5, 10, and 15 min), and storage period on Hardness, hardness rate constant and sensory characteristics of Baeksulgi prepared with optimum formula (rice new 100%, water 60%, salt 1.5%, and sugar 15%). Although the hardness was slowly increased during storage period from 0 hr to 8 hr and sharply increased after 12 hr of storage in case of 0.5 bay steam pressure, it was slowly increased after 12 hr storage time in case of steaming pressure at 1.0 ban Hardness rate constant of Baeksulgi was $0.217{\sim}0.184hr^{-1}$ at range of steaming time for $8{\sim}10$ min and pressure at $0.8{\sim}1.0$ bar which was relatively low. Hardness and elasticity of sensory evaluation were increased with the increases in steaming pressure, steaming time, and storage period but cohesiveness was decreased The highest overall preference was steaming pressure at 10 bar, steaming time for 10 min, and storage period for 12 hr. In conclusion, steaming pressure, steaming tim, and storage period influenced Baeksulgi quality such as hardness and sensory characteristics.

• 한국해양학회지
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• v.25 no.3
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• pp.135-144
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• 1990

Fish assemblage occupying the surf zone habitat of Taecheon sand beach in Cheonsu Bay was analyzed using monthly samples collected by a beach seine from September 1984 through August 1985. During each sampling period five hauls were completed, one at each 2-hour interval during the spring tide. Of 35 species identified, Favonigobius gymnauchen, Sillago japonica, Konosirus punctatus, Sardinella zunasi and chaenogobius mororana accounted for 79% of the individuals collected, and F. gymnauchen, s. japonica, K. punctatus, S. zunasi and Kareius bicoloratus constituted 67% of the biomass obtained. Overall abundance in terms of numbers and in biomass were 0.13 individuals/m$^2$ and 0.33g/m$^2$, respectively. A larger number of individuals and greater biomass was observed during the warmer months showing significant correlation with water temperature. High abundance of June was related to the occurrence of adult F. gymnauchen. A large number of individuals and great biomass was collected in August and September, a period of high abundance in juveniles of the seasonal species such as S. japonica, K. punctatus and S. zunasi. Temperature and habitat occupation according to life history of the dominant species might be the primary factors of the marked seasonality of the surf zone fish populations in the study area.

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.277-292
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• 2020

The purpose of this study is to propose the possibility of precise surface sedimentary facies classification and a more accurate classification method by generating the large-scale map of surface sedimentary facies based on UAV data and object-based image analysis (OBIA) for Hwang-do tidal flat in Cheonsu bay. The very high resolution UAV data extracted factors that affect the classification of surface sedimentary facies, such as RGB ortho imagery, Digital elevation model (DEM), and tidal channel density, and analyzed the principal components of surface sedimentary facies through statistical analysis methods. Based on principal components, input data to be used for classification of surface sedimentary facies were divided into three cases such as (1) visible band spectrum, (2) topographical elevation and tidal channel density, (3) visible band spectrum and topographical elevation, tidal channel density. The object-based image analysis classification method was applied to map the classification of surface sedimentary facies according to conditions of input data. The surface sedimentary facies could be classified into a total of six sedimentary facies following the folk classification criteria. In addition, the use of visible band spectrum, topographical elevation, and tidal channel density enabled the most effective classification of surface sedimentary facies with a total accuracy of 63.04% and the Kappa coefficient of 0.54.

• Journal of architectural history
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• v.14 no.1 s.41
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• pp.71-87
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• 2005

4 royal palaces are currently remained from capital city (Seoul) of 'Cho-Sun(朝鮮)' period. In these palaces, 'Main hall of Royal Palace(正殿)' is the center of the Royal Palaces. The 'Main hall of Royal Palace' of the Royal Palace was the best building of that time. Therefore there were many studies about the 'Main hall of Royal Palace'. But these studies were individual studies of these 'Main hall of Royal Palace'. Therefore, this study is to analyze and compare 4 'Main hall of Royal Palace' of the Royal palaces. It is to study the proportion regarding the Diameter of the pillar, the Height, the pillar and pillar Interval's Distance, and the arrangement of 'Kong-Po(bracket sets)'. With these studies, it is to prove that the 'Main hall of Royal Palace' is the building which high construction technique of this time is expressed. Result of this study is as followings; First, the proportion of pillar height(H) to its diameter(D) average from H=8.0 to 8.5D. Only the Myeong-Jeong-Jeon omitted the 'Go-Ju(高柱)' in the 'Toi-Kan (退間)' to place Ea-Jwa(御座). Second, Second, the proportion of diameter of the pillar of 'Eoi-Bu-Pyeong-Ju(外部平柱)' and 'Nae-Jin-Go-Ju(內陣高柱)' average D1(Diameter of 'Eoi-Bu-Pyeong-Ju') =0.91D2 (Diameter of 'Nae-Jin-Go-Ju'). In regards to the height, the single floor 'Main hall of Royal Palace' and double floor 'Main hall of Royal Palace' seems to be different. The height proportion of the double floor 'Main hall of royal palace' is H1(Height of 'Eoi-Bu-Pyeong-Ju')=0.34H2(Height of 'Nae-Jin-Go-Ju') and single floor 'Main hall of Royal Palace' has a proportion of H1=0.62H2. Third, in Geun-Jeong-Jeon, with the proportion of height and diameter of the pillar, interval's distance between pillars and diameter, the pillar interval distance and height, of 'Ea-kan(御間)' from the 'Toi-Kan' is different from 'Main hall of Royal Palace'. This is because the structure of 'Toi-Kan' of Geun-Jeong-Jeon is not stable. In order to reinforce this, 'Gui-Go-Ju(隅高柱)' of the Geun-Jeong-Jeon jut out $4{\sim}7%$ more compared to In-Jeong-Jeon. Fourth, when comparing double floor 'Main hall of royal palace' of Geun-Jeong-Jeon and In-Jeong-Jeon, based on distance of 'Eoi-Bu-Pyeong-Ju' and 'Nae-Jin-Go-Ju' of lower level, the 'Sang-Bu-Pyeong-Ju(上部平柱)' of Geun-Jeong-Jeon jut out $4{\sim}7%$ more compared to the In-Jeong-Jeon and also It becomes thicker. Fifth, the arrangement of 'Kong-Po' on the front row of 'Gan(間)' had to do with the change of side 'Gan'. Even though the Geun-Jeong-Jeon and the In-Jeong-Jeon were double floors, the arrangement of the 'Kong-Po' is different because the number of side bay is different.

• Geotechnical Engineering
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• v.12 no.5
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• pp.17-26
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• 1996

The undrained behavior of Asan marine soil was investigated by using an automated triaxial testing device. The stress-strain behavior at the preand postfailure state of marine soil under undrained compression and eatension conditions was compared with the behavior of pure silt, pure clay and the overall behavior of Asan marine soil was predicted with the modified Camflay model and the bounding surface model. The marine soil sampled in Asan bay area was clayey silts with 70oA silt-30% clay content and the testing samples were prepared in both undisturbed and remolded conditions. All samples are normally consolidated with 400 kPa of effective mean confining pressure and each sample is unloaded to 200, 100, 67 kPa, respectively. And then the shear test was performed with different confining pressure. According to experimental results, there exists an unique failure line whose slope is lower than silt's and higher than clay's. It is identified that the undrained shear strength of normally consolidated samples increases after crossing the phase transformation line because of volume dilation tendency which is not seen in clay. Overconsolidated samples show different soil behavior compared with pure silt due to its tendency of change in volume. It is also found that the overall behavior of Asan marine soil cannot be predicted precisely with the modified Cam-clay model and the bounding surface model.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.5
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• pp.383-392
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• 2011

The basic research of the estuarine circulation at Gyeong-Gi bay has not been well studied up to now, although coastal development pressures have been continuously increased. To understand the oceanographic phenomena at the Han River estuary, it's essential to understand the propagation characteristic of tidal wave which is the strongest external forcing in this region. In this study, we investigate the tidal wave propagation characteristics along the 3 major channels using observation data and numerical model. It is found that 3 channels are all hyper-synchronous and the most important physical factor controlling the tidal wave propagation is topographical convergence of estuary shape and friction. The result of analytic solution at ideal channel considering the topographical convergence and friction show that the contribution of physical role of convergence and friction varies at 3 different channel. And the ratio of convergence and friction at Yeomha channel is four times larger than Seokmo channel. Because of this effect, the location of maximum amplitude at Yeomha channel is showed up downward than Seokmo channel. The ratio of decreasing amplitude and increasing phase per unit distance between stations is bigger than Seokmo channel. Although 3 major channel show a hyper-synchronous pattern, Yeomha shows more frictionally dominant channel and Seokmo channel is more dominantly affected by convergence effect.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.842-851
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• 1998

Development and growth of Acartia steueri from Ilkwang Bay, southeastern coast of Korea, were determined under various temperatures and food condition (Isochrysis galbana and Dunaliella salina) in the laboratory. Relationship between egg hatching time ($D_E$, day) and temperature (T, $^{\circ}C$) was $D_E=744(T+3.5)^{-1.97}$. Mean hatching success was $88.4\%$ in temperature range of $8.4\~26.2^{\circ}C$. This suggests that A. steueri may be adapted to the temperature ranges in temperate regions. Post-embryonic development pattern was equiproportional rather than isochronal, with longer stage duration of copepodites than that of the nauplii. Stage duration of NI was the shortest of all developmental stages, while the duration of NII was the longest in duration of the other nauplii. Male was morphologically distinguished from female in CIV stage, and male was developed faster than female. Median development time at a given temperature was calculated from the Belehradek equation by proper multiplication of proportional constant for embryonic development. Body carbon weight at $19.1^{\circ}C$ was increased exponentially with time. Mean specific growth rate of nauplii (0.200 $d^{-1}$), except for NI stage, was not significantly different from that of copepodites (0.190 $d^{-1}$), with the lowest rate in NVI stage (0.107 $d^{-1}$), probably due to energy consumption for metamorphosis rather than somatic growth. The results suggest that although the development pattern determined in this study was not identical with Uye's result for A. steueri (e.g. Uye, 1980b), median development time may be applicable to calculate the stage duration of A. steueri in this study area.