• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.11 no.3
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• pp.97-107
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• 2006

The nektonic assemblages of upper tidal flat area located in the Jangbong Island, near Incheon, were studied using a fence net from March to November 2001. A total of 49 species were recorded, with a mean abundance and biomass of 489 individuals and 5,170.4 g, respectively. The most abundant species by number were Exopalaemon carinicauda(40.9%) and Johnius grypotus(13.2%). By catch weight the dominant species were Acanthogobius hasta(33.7%), Johnius grypotus(14.6%) and Scomberomorus niphonius(10.2%). The conventional multivariate statistics(Cluster analysis and non-metric Multi-Dimensional Scaling) applied to assess temporal variation in nektonic communities. As a result of cluster analysis and MDS ordination, the faunal group could be divided into spring and summer/autumn dominant species group. The spring species included the pisces Acanthogobius luridus, the crab Macrophthalmus japonicus and the gastropods Bullacta exarata and Lunatia gilva. The summer/autumn species were the pisces J. grypotus, Sardinella zunasi, Konosirus punctatus, Chelon haematocheila, S. niphonius and Takifugu niphobles, the shrimp Metapenaeus joyneri and the cephalopod Loligo beka.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.3
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• pp.211-218
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• 2007

In this study, we investigated the spatial distribution of macrozoobenthos in the estuarine sandy flat, the Bongam tidal flat located in Masan Bay during March, 2004. A total 13 species were identified at 12 stations within the tidal flat. The mean density was $20,267\;ind./m^2$, and mean biomass was $228.1g/m^2$. Dominant species in the Bongam tidal flat were all polychaetes: Prionospio japonicus ($11,716\;ind./m^2$, 57.8%) and Polydora ligni ($3,929\;ind./m^2$, 19.4%) of spionoid polychaete, and Neanthes succinea ($3,425\;ind./m^2$, 16.9%) of nereid polychaete. The most dominant species, P. japonicus distributed evenly all stations in the tidal flat. But N. succinea showed high density at the upper area of the tidal flat. Species diversity index (H') was in the range of 0.6 to 1.2 which is relatively low due to the prominent of P. japonicus and few species richness at each station. The study area was divided into two station groups (group A and B) based on the cluster analysis and MDS ordination, and the spatial distribution of macrozoobenthos on the Bongam tidal flat seemed to be in the influence of exposure duration from tidal levels and specific geological topography.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.2
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• pp.239-245
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• 2014

Purpose : The purpose of this study is to verify the accuracy of dose delivery according to the pitch and roll rotational setup error with 6D robotic couch in Intensity Modulated Radiation Therapy (IMRT) for pelvic region in patients. Materials and Methods : Trilogy(Varian, USA) and 6D robotic couch(ProturaTM 1.4, CIVCO, USA) were used to measure and analyze the rotational setup error of 14 patients (157 setup cases) for pelvic region. The total 157 Images(CBCT 78, Radiography 79) were used to calculate the mean value and the incidence of pitch and roll rotational setup error with Microsoft Office Excel 2007. The measured data (3 mm, 3%) at the reference angle ($0^{\circ}$) without couch rotation of pitch and roll direction was compared to the others at different pitch and roll angles ($1^{\circ}$, $1.5^{\circ}$, $2^{\circ}$, $2.5^{\circ}$) to verify the accuracy of dose delivery by using 2D array ionization chamber (I'mRT Matrixx, IBA Dosimetry, Germany) and MultiCube Phantom(IBA Dosimetry, Germany). Result from the data, gamma index was evaluated. Results : The mean values of pitch and roll rotational setup error were $0.9^{\circ}{\pm}0.7$, $0.5^{\circ}{\pm}0.6$. The maximum values of them were $2.8^{\circ}$, $2.0^{\circ}$. All of the minimum values were zero. The mean values of gamma pass rate at four different pitch angles ($1^{\circ}$, $1.5^{\circ}$, $2^{\circ}$, $2.5^{\circ}$) were 97.75%, 96.65%, 94.38% and 90.91%. The mean values of gamma pass rate at four different roll angles ($1^{\circ}$, $1.5^{\circ}$, $2^{\circ}$, $2.5^{\circ}$) were 93.68%, 93.05%, 87.77% and 84.96%. when the same angles ($1^{\circ}$, $1.5^{\circ}$, $2^{\circ}$) of pitch and roll were applied simultaneously, The mean values of each angle were 94.90%, 92.37% and 87.88%, respectively. Conclusion : As a result of this study, it was able to recognize that the accuracy of dose delivered is lowered gradually as pitch and roll increases. In order to increase the accuracy of delivered dose, therefore, it is recommended to perform IGRT or correct patient's position in the pitch and roll direction, to improve the quality of treatment.

• Journal of Animal Science and Technology
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• v.46 no.3
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• pp.301-306
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• 2004

This study was conducted to develop new markers at the region that was related to QTL affecting intramuscular fat and backfat thickness on chromosome 6q28 - 6q32 in pigs. Dozens of repeated sequences were founded using shotgun sequencing of several BAC clones corresponding to that region, of which five new microstellite markers that identified polymorphism were discovered. The mean number of alleles at each locus observed 2.13(KP0290F2), 4.63(KP0248Cll), 7.38(KP1231C91), 2.75(KPI23IC92) and 6.2S(KP1231C93) in 8 breeds(Landrace, Korean native pig, Duroc, Yorkshire, Berkshire, Wuzhishan pig, Xiang pig, Min pig). The average estimated heterozygosity values at each locus varied from 0.2100(KP0290F2) to 0.8304(KPI23IC91) in all populations. In other hand, the average allele of all loci WlL'I within range of 0.4517(Berkshire) and 0.6957 (Yorkshire). Of these markers, KP0248C11, KP1231C91 and KP1231C93 were identified to have optimal number of alleles, high heterozygosity values and low standard deviation values. Especially, KPI23IC91 and KPI231C93 might be considered as a useful marker for genetic mapping and diversity study.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.331-337
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• 2014

Purpose: This is a comparative experimental study on the amount of phoria by the removal time of binocular fusion. In this study, three tests were used for phoria test like Howell test, Thorington test and developed 3D polarizing test. Methods: In this study, it was considered the removal time of binocular fusion for measuring phoria. The three methods were used for measuring quantity of phoria: Howell test, Thorington test and developed 3D Polarizing test. The measurements progressed quickly to avoid eye-strain. So we designed the test charts for marking 3D display modules and the apparatus inserted lenses, like Maddox lens and prism, which are compatible with three phoria tests. The phoria at the moment separation was measured when the binocular fusion was broken through the apparatus and the that at the stable separation was measured when activity of the separated two images like indicated box and figure on horizontal axis stopped. Results: There were statistically significant difference between quantity of phoria at moment separation and that at stable separation. Amount of phoria at moment separation was relatively larger than amount of that at stable separation. In result in exophoria, the quantity of phoria at moment separation was higher than that at stable separation, and in phoria measured by developed 3D polarizing test, it shows the similar results at two condition. Conclusions: For exophoria, the amount of phoria at moment separation of binocular fusion was relatively larger than that at stable separation. The amount of difference between phoria values at moment separation and that at stable separation was alike among three phoria tests. Usually in working, there is no distinction between moment separation and stable separation. But there were definitely the difference between two ways to separate binocular fusion. Therefore, it is need for writing on prescription test name for measuring phoria and condition of separation of binocular fusion.

• Journal of the Korean Geographical Society
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• v.42 no.4
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• pp.488-505
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• 2007

The purposes of this research are twofold; 1) to verify spatial differences of tectonic movement using the spatial distribution of earthquakes, and 2) to infer mechanisms that generate spatial accumulation patterns of earthquakes in the Korean Peninsula. The first part of this sequential paper (Park, 2007) argues that the Korean Peninsula consists of four geostructural regions in which tectonic deformation and consequent geomorphological development patterns are different from each other Since this conclusion has been made by terrain analyses alone, it is necessary to verify this suggestion using other independent geophysical data. Because earthquakes are results of movement and deformation of land masses moving in different directions, the distribution of earthquake epicenters may be used to identify the direction and rates of land mass movement. This paper first analysed the spatial distribution of earthquakes using spatial statistics, and then results were compared with the spatial arrangement of geostructural regions. The spatial distribution of earthquakes in the Korean Peninsula can be summarized as the followings; firstly, the intensity of earthquakes shows only weak spatial dependency, and shows large difference even at adjacent regions. Secondly, the epicenter distribution has a clear spatial accumulation pattern, even though the intensity of earthquake shows a random pattern. Thirdly, the high density area of earthquakes shows a clear 'L' shape, passing through Pyeongannam-do, centered at Pyeongyang, and Hwanghae-do, Seosan and Pohang. The correlation coefficient between the density of earthquakes and distance from geostructral region boundaries is much higher than those between the density of fault lines and distance from tectonic division boundaries. Since fault lines and tectonic divisions in the Korean Peninsula are the results of long-term geological development, there is an apparent scale discrepancy to find significant correlations with earthquakes. This result verifies the research hypothesis that the Korean Peninsula is divided into four geostructral regions in which each has its own moving direction and spatial deformation characteristics. The existence of geostructural regions is also supported by the movement parrerns of land masses estimated from the GPS measurements. This conclusion is expected to provide a new perspective to understand the geomorphological developments and the earthquake occurrences in the Korean Peninsula.

• Journal of Soil and Groundwater Environment
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• v.7 no.3
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• pp.3-17
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• 2002

Data analysis of groundwater monitoring wells and geostatistical methods are used to identify the local characteristics of sea water intrusion and the range of sea water intrusion at the southeastern coastal area of Busan, Korea. Rainfall and groundwater level of two monitoring wells show a linear correlation because of the direct groundwater recharge by the precipitation. However, rainfall and electric conductivity have the inverse relationship because of the increase of groundwater. Electric conductivity rapidly increased at 24m depth and exceeded 20,000$\mu\textrm{s}$/cm near 26m depth in the monitoring wells. The variations of groundwater level and electric conductivity show that the interface between sea water and fresh water tends to move upward when groundwater level goes down. In the cross correlation analysis, groundwater level versus rainfall represents the largest cross correlation coefficient in 0 time lag but the cross correlation coefficient of electric conductivity versus rainfall is the largest when the time lag is 9 days. This suggests that the fluctuations of groundwater level respond to rainfall in a short time, but the interface between sea water and fresh water respond very slow to rainfall. Horizontal extents of sea water intrusion are estimated to 14 m from the east of Line 1, and 25 m from the southeast end of Line 2 in the inversion of dipole-dipole profiling data of two survey lines. The data of VES by the Schulumberger array in May and July show lognormal distributions. In the kriged apparent resistivity and earth resistivity distributions, the resistivities of July are increased comparing to those of May. This reflects that the concentration of sea water in aquifer is reduced due to the increased groundwater recharge from the rainfall in June and July. In analyzing the vertical and horizontal apparent resistivities and earth resistivity distributions, the geostatistical methods are very useful to identify the variations of earth resistivity distributions at the coastal area.

• The Journal of the Petrological Society of Korea
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• v.27 no.1
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• pp.1-15
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• 2018

The characteristics of the rock cleavage of Jurassic Geochang granite were analysed using the distribution of microcrack lengths and spacings. The length and spacing-cumulative diagrams for the six directions of rock cleavages were arranged in increasing order ($H2{\rightarrow}R1$) on the density (${\rho}$) of microcrack length. The various parameters were extracted through the combination of above two types of diagrams. The evaluation for the six directions of rock cleavages was performed using the four groups (I~IV) of parameters such as (I) intersection angle (${\alpha}-{\beta}$), exponent difference (${\lambda}_S-{\lambda}_L$), length of line (ol and ll'), length ratio (ol/os and ll'/sl'), mean length ((ss'+ll')/2), area of right-angled triangle (${\Delta}oaa_a^{\prime}$ and ${\Delta}obb_a^{\prime}$) and area difference (${\Delta}obb^{\prime}-{\Delta}oaa^{\prime}$ and ${\Delta}obb_a^{\prime}-{\Delta}oaa_a^{\prime}$), (II) length of line (oa and os) and area (${\Delta}oaa^{\prime}$), (III) length of line (sl') and length ratio (ss'/ll') and (IV) length of line (ob, ss' and ls') and area (${\Delta}obb^{\prime}$, ${\Delta}ll^{\prime}s^{\prime}$, ${\Delta}ss^{\prime}l^{\prime}$ and ⏢ll'ss'). The results of correlation analysis between the values of parameters for three rock cleavages and those for three planes are as follows. The values of parameters for three rock cleavages are in orders of (I) H(hardway, (H1 + H2)/2) < G(grain, (G1 + G2)/2) < R(rift, (R1 + R2)/2), (II) R < G < H, (III) G < H < R and (IV) H < G < R. On the contrary, the values of parameters for three planes are in orders of (I) R' < G' < H', (II) H' < G' < R' and (III and IV) R' < H' < G'. Especially the values of parameters belonging to group I and group II show mutual reverse orders. In conclusion, this type of correlation analysis is useful for discriminating three quarrying planes.

• Progress in Medical Physics
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• v.26 no.2
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• pp.87-92
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• 2015

The gated RapidArc may produce a dosimetric error due to the stop-and-go motion of heavy gantry which can misalign the gantry restart position and reduce the accuracy of important factors in RapidArc delivery such as MLC movement and gantry speed. In this study, the effect of stop-and-go motion in gated RapidArc was analyzed with varying gating window time, which determines the total number of stop-and-go motions. Total 10 RapidArc plans for treatment of liver cancer were prepared. The RPM gating system and the moving phantom were used to set up the accurate gating window time. Two different delivery quality assurance (DQA) plans were created for each RapidArc plan. One is the portal dosimetry plan and the other is MapCHECK2 plan. The respiratory cycle was set to 4 sec and DQA plans were delivered with three different gating conditions: no gating, 1-sec gating window, and 2-sec gating window. The error between calculated dose and measured dose was evaluated based on the pass rate calculated using the gamma evaluation method with 3%/3 mm criteria. The average pass rates in the portal dosimetry plans were $98.72{\pm}0.82%$, $94.91{\pm}1.64%$, and $98.23{\pm}0.97%$ for no gating, 1-sec gating, and 2-sec gating, respectively. The average pass rates in MapCHECK2 plans were $97.80{\pm}0.91%$, $95.38{\pm}1.31%$, and $97.50{\pm}0.96%$ for no gating, 1-sec gating, and 2-sec gating, respectively. We verified that the dosimetric accuracy of gated RapidArc increases as gating window time increases and efforts should be made to increase gating window time during the RapidArc treatment process.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.3
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• pp.157-167
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• 2021

Lead (Pb) is one of the key trace elements, exhibiting a peculiar partitioning behavior into silicate melts in contact with minerals. Partitioning behaviors of Pb between silicate mineral and melt have been known to depend on melt composition and thus, the atomic structures of corresponding silicate liquids. Despite the importance, detailed structural studies of Pb-bearing silicate melts are still lacking due to experimental difficulties. Here, we explored the effect of lead content on the atomic structures, particularly the evolution of silicate networks in Pb-bearing sodium metasilicate ([(PbO)_x(Na₂O)_1-x]·SiO₂) glasses as a model system for trace metal bearing natural silicate melts, using ²⁹Si solid-state nuclear magnetic resonance (NMR) spectroscopy. As the PbO content increases, the ²⁹Si peak widths increase, and the maximum peak positions shift from -76.2, -77.8, -80.3, -81.5, -84.6, to -87.7 ppm with increasing PbO contents of 0, 0.25, 0.5, 0.67, 0.86, and 1, respectively. The ²⁹Si MAS NMR spectra for the glasses were simulated with Gaussian functions for Qⁿ species (SiO₄ tetrahedra with n BOs) for providing quantitative resolution. The simulation results reveal the evolution of each Qⁿ species with varying PbO content. Na-endmember Na₂SiO₃ glass consists of predominant Q² species together with equal proportions of Q¹ and Q³. As Pb replaces Na, the fraction of Q² species tends to decrease, while those for Q¹ and Q³ species increase indicating an increase in disproportionation among Qⁿ species. Simulation results on the ²⁹Si NMR spectrum showed increases in structural disorder and chemical disorder as evidenced by an increase in disproportionation factor with an increase in average cation field strengths of the network modifying cations. Changes in the topological and configurational disorder of the model silicate melt by Pb imply an intrinsic origin of macroscopic properties such as element partitioning behavior.