• Journal of Aquaculture
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• v.2 no.1
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• pp.21-32
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• 1989

This study was undertaken to understand development stage of ovary and changes of hormone concentrations in the Israeli carp, Cyprinus carpio from Ferbruary to May. The results obtained in these experiments are as follows: 1. Serum LH levels began to increase sharply in March, coinciding with the onset of rapid ovarian development. 2. LH levels were well correlated with changes in gonadosomatic index. 3. Dramatic increase in gonadosomatic index occured during the months of March. 4. Ripe stage(Stage VII) rapidly increase in March. 5. Early perinucleolus oocyte rapidly develop into late perinucleolus oocytes in March. 6. The vitellogenic phase begins as these late perinucleolus oocytes become transformed into early maturing oocytes through the accumulation of yolk. 7. The cytoplasm completely fills with yolk as oocytes reach the late maturing stage. 8. Changes in the microscopic appearances of the ovaries were well correlated with changes in both gonadosomatic index and macroscopic appearance. 9. It is concluded from these observations that LH plays a major role in sexual maturating of the Israeli carp.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.41.1-41.1
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• 2016

We present the physical properties of KIC 6220497 exhibiting multiperiodic pulsations from the Kepler photometry. The light curve synthesis represents that the eclipsing system is a semi-detached Algol with a mass ratio of q=0.243, an orbital inclination of i=77.3 deg, and a temperature difference of ${\Delta}T=3,372K$, in which the detached primary component fills its Roche lobe by ~87% and is about 1.6 times larger than the lobe-filling secondary. To detect reliable pulsation frequencies, we analyzed separately the Kepler light curve at the interval of an orbital period. Multiple frequency analyses of the eclipse-subtracted light residuals reveal 32 frequencies in the range of $0.75-20.22d^{-1}$ with semi-amplitudes between 0.27 and 4.55 mmag. Among these, four frequencies ($f_1$, $f_2$, $f_5$, $f_7$) may be attributed to pulsation modes, while the other frequencies can be harmonic and combination terms. The pulsation constants of 0.16-0.33 d and the period ratios of $P_{pul}/P_{orb}=0.042-0.089$ indicate that the primary component is a ${\delta}$ Sct pulsating star in p modes and, thus, KIC 6220497 is an oscillating eclipsing Algol (oEA) star. The dominant pulsation period of about 0.1174 d is considerably longer than the values given by the empirical relations between the pulsational and orbital periods. The surface gravity of log $g_1=3.78$ is significantly smaller than those of the other oEA stars with similar orbital periods. The pulsation period and the surface gravity of the pulsating primary demonstrate that KIC 6220497 would be the more evolved EB, compared with normal oEA stars.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1268-1277
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• 2008

Recently, the high speed railway comes into the spotlight as the important and convenient traffic infrastructure. In Korea, Kyung-Bu high speed train service began in about 400km section at 2004, and the Ho-Nam high speed railway will be constructed by 2017. The high speed train will run with a design maximum speed of 300-350km/hr. Since the trains are operated at high speed, the differential settlement of subgrade under the rail is able to cause a fatal disaster. Therefore, the differential settlement of the embankment must be controlled with the greatest care. Furthermore, the characteristics and causes of settlements which occurred under construction and post-construction should be investigated. A considerable number of studies have been conducted on the settlement of the natural ground over the past several decades. But little attention has been given to the compression settlement of the embankment. The long-term settlement of compacted fills embankments is greatly influenced by the post-construction wetting. This is called 'hydro collapse' or 'wetting collapse'. This wetting collapse problem for the compressibility of compacted sands, gravels and rockfills, has been recognized by several researchers. For this wetting settlement problem, we showed the test results carried out with 4 fill materials. These tests were performed under the condition that the fill materials were inundated at the first wetting. Subsequently, in this study, we investigated the long-term settlement characteristics of the fill materials under the repeated partial wetting and rising of the ground water table happend by rainfall.

• Steel and Composite Structures
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• v.27 no.4
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• pp.509-523
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• 2018

This paper presents experimental results on the residual bond-slip behavior of high strength concrete-filled square steel tube (HSCFST) after elevated temperatures. Three parameters were considered in this test: (a) temperature (i.e., $20^{\circ}C$, $200^{\circ}C$, $400^{\circ}C$, $600^{\circ}C$, $800^{\circ}C$); (b) concrete strength (i.e., C60, C70, C80); (c) anchorage length (i.e., 250 mm, 400 mm). A total of 17 HSCFST specimens were designed for push-out test after elevated temperatures. The load-slip curves at the loading end and free end were obtained, in addition, the distribution of steel tube strain and the bond stress along the anchorage length were analyzed. Test results show that the shape of load-slip curves at loading ends and free ends are similar. With the temperature constantly increasing, the bond strength of HSCFST increases first and then decreases; furthermore, the bond strength of HSCFCT proportionally increases with the anchoring length growing. Additionally, the higher the temperature is, the smaller and lower the bond damage develops. The energy dissipation capacity enhances with the concrete strength rasing, while, decreases with the temperature growing. What is more, the strain and stress of steel tubes are exponentially distributed, and decrease from the free end to loading end. According to experimental findings, constitutive formula of the bond slip of HSCFST experienced elevated temperatures is proposed, which fills well with test data.

• Journal of the Korean Geophysical Society
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• v.2 no.3
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• pp.201-208
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• 1999

A high-resolution seismic profile acquired across the middle part of the Pungam Basin, one of the Cretaceous sedimentary basins in Korea, has been interpreted to delineate subsurface geological structures. Boundary faults, intrusive bodies, and unconformity surfaces are identified on the seismic section. Basin fills are divided into five depositional units (Units I, II, III, IV, and V in descending order). The normal faults were formed by transtentional movement along a sinistral strike-slip fault zone. Unconsolidated sediments, a weathered layer, and sedimentary layers overly the Precambrian gneiss. The granite body intruded at the southeastern part contacts the adjacent sedimentary rocks by a near-vertical fault. Granitic intrusions caused tectonic fractures and normal faults of various sizes. An andesitic intrusive body indicates post-depositional magmatic intrusions. Continuous strike-slip movements have deformed basin-filling sediments (Units I and II).

• Journal of the Korea Society of Computer and Information
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• v.23 no.10
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• pp.165-172
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• 2018

This study was conducted to investigate the relationship between life satisfaction of the elderly and their transfer income (public transfer and private transfer income) using the 11th data of the Korea welfare panel study. In the analysis results, the public transfer income was analyzed to have a significantly positive (+) effect on the life satisfaction in the case of the elderly in general households while in the case of the elderly in low income households, private transfer income was analyzed to have a significantly positive (+) effect on life satisfaction. These results suggest that the public transfer income is 1,019,200 won (monthly average 849,000 won) in the case of the elderly in general households, and the public transfer income is found to have an effect to stabilize the income, which can be expected to increase the life satisfaction. However, in the case of the elderly in low income households, it was found to be 5,080,500 won (monthly average 424,000 won), half of the public transfer income of the elderly in general households. In the case of the elderly of low income households, it can be assumed that the private transfer income, which is the "uncomfortable" income source, fills up the unstable income stabilization gap and raises the life satisfaction. As a policy suggestion, first, by supplementing the basic pension system, which is an irrational part of public transfer income for the elderly with low income, it is necessary to design policy alternatives to enable economic stabilization of the elderly in low income households. Second, it is also necessary to actively review the introduction of income deduction plans for the transfer income of family members for the low income elderly households.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.201-204
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• 2015

The common-envelope process is a complicated phase in binary evolution. A lot of effort has been dedicated to study the common-envelope stage, but many questions related to this process are yet to be answered. If one member of the binary survives the common-envelope phase, the binary will emerge as a white dwarf accompanied by a low-mass main sequence star in close orbit, often referred as a post common-envelope binary (PCEB). SDSS J0745+2631 is among the list of newly found PCEBs from the Sloan Digital Sky Survey (SDSS). This star is proposed to be a strong eclipsing system candidate due to the ellipsoidal modulation in its light curve. In this work, we aim to confirm the eclipsing nature of SDSS J0745+2631 and to determine the stellar and orbital parameters using the software Binary Maker 3.0 (BM3.0). We detected the primary eclipse in the light curve of SDSS J0745+2631 in our follow-up observation from January 2014 using the ULTRASPEC instrument at the Thai National Observatory. The data obtained on 7th and 8th January 2014 in g filter show an evident drop in brightness during the eclipse of the white dwarf, but this eclipse is less prominent in the data taken on the next night using a clear filter. According to our preliminary model, we find that SDSS J0745+2631 hosts a rather hot white dwarf with an effective temperature of 11500K. The companion star is a red dwarf star with a temperature of 3800K and radius of 0.3100 $R_{\odot}$. The red dwarf star almost fills its Roche lobe, causing a large ellipsoidal modulation. The mass ratio of the binary given by the Binary Maker 3.0 (BM3.0) model is M2/M1 = 0.33.

• Journal of the Korean Geotechnical Society
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• v.20 no.1
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• pp.91-99
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• 2004

Researches on the induced trench method using compressible materials such as clay, mud, straw have been performed to reduce the load acting on buried conduits under a high fill in USA and Canada. And in-situ tests on load reductionmethod using EPS block as a compressible inclusion have been performed in Japan and Norway. Using a EPS block as a compressible materials can have various benefits such as cost-effective design, enlargement of safety and easy construction of structure under high fills. This paper analyzes the arching material function of EPS which can result in reduction of earth pressure by arching effect in Corrugated Steel Pipe. A series of tests were conducted to evaluate the reduction of earth pressure on conduits using EPS. Based on field test it is found that the magnitude of vertical earth pressure on conduits was reduced to about 35∼40% compared with conventional flexible conduit systems.

• Journal of the Korea Concrete Institute
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• v.13 no.2
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• pp.139-145
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• 2001

One of ways to make high-strength concrete is for the mix contain particles graded down to the finest size : this is achieved by the use of fly ash, silica fume which fills the spaces between the cement particle and between the aggregate and the cement particles. And, the mix needs a sufficient workability. This is achieved by the use of a superplasticizer. This study is to investigate frost resistance of high-strength concrete at early age, with ratio of tensile strength and recovery of compressive strength, when high-strength concrete is placed in cold climates. According to this study, it is necessary to ensure 4 % of air content, 5 kgf/$\textrm{cm}^2$ of tensile strength, at least, for frost resistance of high-strength concrete at early age.

• Strategy21
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• s.44
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• pp.103-141
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• 2018

As the South China Sea maritime dispute illustrates, when considering the place where maritime claims occur, states do not have many choices to respond to maritime claims in which disputed areas are located far away from the land and are surrounded by the sea. As Mearsheimer (2014) points out, the sea stops power projection. Therefore, in order to adopt coercive as well as peaceful settlement policies to deal with maritime claims, states need to overcome obstacles (the sea) to project power. It means that if states want to conduct a specific foreign policy action, such as negotiating maritime borderlines or arguing sovereignty on islands, they need a tool (naval power) to coerce or to persuade the opponent. However, there are lack of research that studies maritime claims from the perspective of naval power. This research project fills this gap based on naval power. How do relative levels of naval power and (dis) parities of naval power influence the occurrence of MIDs over maritime claims? Naval power is a constitutive element during maritime claims. If disputants over maritime claims have required naval power to project their capability, it means that they have the capability to apply various ways, such as aggressive options including MIDs, to accomplish their goals. So, I argue that when two claimants have enough naval power to project their capabilities, the likelihood of MIDs over maritime claims increases. Given that one or both states have a certain level of naval power, how does relative naval power between two claimants influence the management of maritime claims? Based on the power transition theory, I argue that when the disparities of relative naval power between claimants becomes distinctive, militarized conflicts surrounding maritime territory are less probable. Based on the ICOW project which codes maritime claims from 1900 to 2001, the empirical results of the Poisson models show if both claimants have projectable naval power, the occurrence of MIDs over maritime claims increases. In addition, the result shows that when disputants maintain similar relative naval powers, they are more likely to initiate MIDs over maritime claims. To put it differently, if naval capabilities' gap between two claimants becomes larger, the probability of the occurrence of MIDs decreases.