• Journal of the Korean Geotechnical Society
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• v.36 no.2
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• pp.5-15
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• 2020

The liquefaction phenomenon that occurred during the Pohang earthquake (M_L=5.4) brought new awareness to the people about the risk of liquefaction caused by the earthquake. Liquefaction hazard maps with 2 km grid made in 2014 used more than 100,000 borehole data for the whole country, and regions without soil investigation data were produced using interpolation. In the mapping of macro liquefaction hazard for the whole country, the site amplification effect and the ground water level 0 m were considered. Recently, the Ministry of Public Administration and Security (2018) published a new site classification method and amplification coefficient of the common standard for seismic design. Therefore, it is necessary to rewrite the liquefaction hazard map reflecting the revised amplification coefficient. In this study, the results of site classification according to the average shear wave velocity in soils before and after revision were compared in the whole country. Also, liquefaction assessment results were compared in Gangseo-gu, Busan. At this time, two ground accelerations corresponding to the 500 and 1,000 years of return period and two ground water table, 5 m for the average condition and 0 m the extreme condition were applied. In the drawing of liquefaction hazard map, a 500 m grid was applied to secure a resolution higher than the previous 2 km grid. As a result, the ground conditions that were classified as S_C and S_D grounds based on the existing site classification standard were reclassified as S₂, S₃, and S₄ through the revised site classification standard. Also, the result of the Liquefaction assessments with a return period of 500 years and 1,000 years resulted in a relatively overestimation of the LPI applied with the ground amplification factor before revision. And the results of this study have a great influence on the liquefaction assessment, which is the basis of the creation of the regional liquefaction hazard map using the amplification factor.

• Journal of the Korean Geosynthetics Society
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• v.15 no.4
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• pp.71-78
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• 2016

In this study, execution costs of the foundation system are compared with PHC and steel pile in the same soil layers and load condition. Steel piles installed on the thin weathered rock are reduced as 12.5% in comparison with the number of PHC piles. Steel piles installed on the soft rock through weathered rock with 1.7m of thickness reduce the number of piles as 35.7% (STK 400) and 46.4% (STK 490), respectively, in comparison with PHC piles installed on the weathered rock. Also, they reduce the number of piles as 26.5% (STK 400) and 38.8% (STK 490), respectively, in comparison with steel piles (STK 400) installed on the weathered rock. When the thickness of footings is constant, steel piles installed on the soft rock may reduce the area of footings up to 12.2% (STK 400) and 45.4% (STK 490), respectively, in comparison with PHC piles installed on the weathered rock. Total cost of foundation system installed on the soft rock with steel piles (STK 400) increases as 12%, whereas in case of replaced with steel piles (STK 490), it reduces as 16% in comparison with PHC piles installed on the weathered rock. This is because the cost reduction due to the number of piles and footing area is more effective despite high cost of steel piles (STK 490). When the thickness of weathered rock is less than 5m, installing steel piles (STK 490) on the soft rock through it is more economic in comparison with installing PHC piles on the weathered rock.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.8
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• pp.870-876
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• 2005

The multiple regression models which have two factors(population and commercial area) have been used to forecast the water demand in the future. But, the coefficient of population had a negative value because proper regional classification wasn't performed, and it is not reasonable because the population must be a positive factor. So, the regional classification was performed by principal component and cluster analysis to solve the problem. 6 regional characters were transformed into 4 principal components, and the areas were divided into two groups according to cluster analysis which had 4 principal components. The new regression models were made by each group, and the problem was solved. And, the future water demands were estimated by three scenarios(Active, moderate, and passive one). The increase of water demand ore $89.034\;m^3/day$ in active plat $49,077\;m^3/day$ in moderate plan, and $19,996\;m^3/day$ in passive plan. The water supply ability as scenarios is enough in water treatment plant, however, 2 reservoirs among 4 reservoirs don't have enough retention time in all scenarios.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.3
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• pp.286-292
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• 2008

This study was conducted to analyze and determine the formation potential of chlorination DBPs from seven urinary compounds with or without Br$^-$. Three of seven components were kynurenine, indole and uracil that were relatively shown high the formation potential of chlorination DBPs concentrations. The reported results of THMs/DOC with or without Br$^-$ in kynurenine showed that THMs/DOC was detected 86.9 $\mu$g/mg when Br$^-$ was not added, and THMs/DOC was detected 100.8 $\mu$g/mg when Br$^-$ was presented. In indole, THMs/DOC was increased from 6.58 $\mu$g/mg to 31.4 $\mu$g/mg when Br$^-$ was added. Moreover, among them, the highest, second-highest and third-highest HAAs/DOC were shown in kynurenine, uracil and indole respectively. Specially, HAAs/DOC was significantly deceased in kynurenine and indole when Br$^-$ was presented. This was a totally different phenomenon for THMs/DOC. TCAA was dominated in HAAs for kynurenine and indole, and DCAA was also dominated in HAAs for uracil. The highest formation of HANs/DOC was shown in kynurenine whether or not Br$^-$ presented, and DCAN was predominant in HANs. HANs was not formed by chlorination in uracil. In addition, the formation of CH/DOC was relatively low in kynurenine and indole. The formation of CH/DOC was specially high(1,270 $\mu$g/mg) in uracil when Br$^-$ was not added. The formation of CH/DOC was 1,027 $\mu$g/mg in uracil when Br$^-$ was added. The formations of THMs and HAAs were also investigated in kynurenine, indole and uracil when Br$^-$ was presented or not. The formation of THMs/DOC was higher in kynurenine and indole when Br$^-$ was presented. The formation of HAAs/DOC was reduced in kynurenine when Br$^-$ was added. The result could be attributed to higher formation of THMs/DOC in kynurenine when Br$^-$ was added. The formation of HAAs/DOC was also reduced in indole when Br$^-$ was added. To the contrary, this result was not attributed to higher formation of THMs/DOC in indole when Br$^-$ was added.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.4
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• pp.283-288
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• 2013

To evaluate the ability of the submerged plant, Ceratophyllum demersum's (C. demersum) to remove nutrients and to inhibit growth of cyanobacteria, a total of 6 mesocosms were conducted in a batch reactor for 9 days. From the 84 hr of the experiment, C. demersum was stabilized and showed daily cycle trends according to changes in pH and DO levels. The concentration of nutrients, $NH_3{^+}$, $NO_3{^-}$ and $PO_4{^3}$ continuously decreased until 9 days of the experiment, with the rapid decrease in nutrient concentration for the first 24 hours. High correlation coefficient ($r^2{\geq}0.96$, p<0.001) between the amount of C. demersum's biomass per unit area and the nutrients removal level were derived, and greater C. demersum's biomass per unit area showed higher removal efficiency of nutrients. However, there were differences in the C. demersum's activity level between batch reactors with higher and similar density of the C. demersum, but nonetheless water purification effect appears to have a significant influence due to attached algae and microorganisms. The growth rate of harmful cyanobacteria, Microcystis aeruginosa (M. aeruginosa) with C. demersum's density of 2,500 g $fw/m^2$ (100% of cover degree) was 0.31 /day, compared to the growth rate of 0.47 /day for the control group (0% of cover degree). In terms of number of cells, the control group had 1.7 times higher number of cells than the experimental group, proving that C. demersum has the ability to inhibit the growth of harmful cyanobacteria.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.2
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• pp.60-67
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• 2002

To determine whether nitrogen (N) uptake by phytoplankton below the euphotic zone in the Yellow Sea is considerable, we measured the uptake rates of nitrate and ammonium using $^{15}N$-labeled stable isotope $K^{15}NO_{3}$ and $^{15}NH_{4}Cl$, in May and November 1997 at total 10 stations. Depth-integrated uptake rates of nitrate and ammonium over the euphotic zone during this study ranged from 1.8 to 15.3 mg N $m^{-2}$ $d^{-1}$ and from 5.0 to 132.2 mg N $m^{-2}$ $d^{-1}$, respectively, and ammonium uptake predominated at 9 of 10 stations (1.9-19.4 fold). Depth-integrated uptake rates of nitrate and ammonium over the whole water column ranged from 2.9 to 22.0 mg N $m^{-2}$ $d^{-1}$ and from 15.7 to 175.5 mg N $m^{-2}$ $d^{-1}$, respectively. The significant proportion of whole water column N uptake was attributed to uptake by phytoplankton below the euphotic zone, ranging from 13.0 to 86.2% for nitrate and from 13.8 to 67.8% for ammonium, indicating that phytoplankton N uptake below the euphotic zone is at times considerable in the study area. The results suggest that when phytoplankton below the euphotic zone in the Yellow Sea are again entrained into the euphotic zone by a certain physical forcing such as turbulent mixing and the vertical movement of thermocline, these episodic events may significantly affect the material fluxes within the euphotic zone. Furthermore, the results suggest that a portion of regenerated production estimated from $^{15}N$-ammonium uptake should be included in new production estimates, which otherwise could be underestimated in the Yellow Sea.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.2
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• pp.51-59
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• 2002

The seasonal variation in species composition and abundance distribution of zooplankton was studied in the Seomjin river estuary along the salinity gradients. In this estuary, marine taxa predominated in all seasons and very limited number of freshwater species appeared. The total abundances showed a seasonal fluctuation. The highest total abundance appeared in spring with over 3,000 individuals/m$^3$. In summer, the high abundance was sustained although it decreased a little. The abundance was minimal in fall with about 500 individuals/m$^3$. When the study area was divided into three salinity regimes, oligohaline (salinity less than 5 psu), mesohaline (5${\sim}$18 psu), and polyhaline zone (over 18 psu), the zone of high abundance as well as the composition of zooplankton community in each salinity regime changed seasonally. In fall, marine copepods predominated in oligohaline zone while marine species other than crustaceans dominated in polyhaline zone. However, in winter copepods predominated in all area. In spring and summer, holozoic dinoflagellate Noctiluca scintillans dominated in higher salinity regimes. We listed major copepod species of each salinity regime for each season with the ranges of water temperatures (T) and salinities (S) of their occurrence. T, S's of maximum abundances of those major copepod species were also reported. The observed very wide tolerance ranges of major copepod species for salinity suggested that the concept of 'indicator species' should be used in quantitative context rather than qualitative.

• The Korean Society of Law and Medicine
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• v.17 no.2
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• pp.177-219
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• 2016

A commercial advertisement is not only a way of competition but also a medium of communication. Thus, it is under the constitutional protection of the freedom of business (article 15 of the Constitution) as well as the freedom of press [article 21 (1) of the Constitution]. In terms of the freedom of business or competition, it should be noted that an unfair advertising (false or misleading advertisement) can be regulated as an unfair competition, while any restraint on advertising other than unfair one might be doubted as an unjustifiable restraint of trade. In terms of the freedom of press or communication, it is important that article 21 (2) of the Constitution forbids any kind of (prior) censorship, and the Constitutional Court applies this restriction even to commercial advertising. In this article, the applicability of these schemes to advertising of the so-called learned professions, especially physician, are to be examined, and some proposals for the reformation of the current regulatory regime are to be made. Main arguments of this article can be summarized as follows: First, the current regime which requires advance review of physician advertising as prescribed in article 56 (2) no. 9 of Medical Act should be reformed. It does not mean that the current interpretation of article 21 of the Constitution is agreeable. Though a commercial advertising is a way of communication and can be protected by article 21 (1) of the Constitution, it should not be under the prohibition of censorship prescribed by article 21 (2) of the Constitution. The Constitutional Court adopts the opposite view, however. It is doubtful that physician advertising needs some prior restraint, also. Of course, there exists severe informational asymmetry between physicians and patients and medical treatment might harm the life and health of patients irrevocably, so that medical treatment can be discerned from other services. It is civil and criminal liability for medical malpractice and duty to inform and not regulation on physician advertising, to address these differences or problems. Advance review should be abandoned and repelled, or substituted by more unproblematic way of regulation such as an accreditation of reviewed advertising or a self-regulation preformed by physician association independently from the Ministry of Health and Welfare or any other governmental agencies. Second, the substantive criteria for unfair physician advertising also should correspond that of unfair advertising in general. Some might argue that a learned profession, especially medical practice, is totally different from other businesses. It is performed under the professional ethics and should not persue commercial interest; medical practice in Korea is governed by the National Health Insurance system, the stability of which might be endangered when commercial competition in medical practice be allowed. Medical Act as well as the condition of medical practice market do not exclude competition between physicians. The fact is quite the opposite. Physicians are competing even though under the professional ethics and obligations and all the restrictions provided by the National Health Insurance system. In this situation, regulation on physician advertising might constitute unjustifiable restraint of competition, especially a kind of entry barrier for 'new physicians.'

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.2
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• pp.125-131
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• 2017

'Saeyoung', a winter triticale (X Triticosecale Wittmack) for forage, was developed at the Department of Rice and Winter Cereal Crop, NICS, RDA in 2012. The cultivar 'Saeyoung' has narrow and long leaves of light green color, middle size and thin culm, and a medium grain of brown color. The heading date and yellow ripe stage of 'Saeyoung' was May 3 and May 27, which were similar to check cultivar 'Shinyoung', respectively. 'Saeyoung' showed a little stronger in cold tolerance and a little weaker in resistance to lodging than the check, and wet injury, powdery mildew, and leaf rust were similar to those of the check cultivar. The forage fresh and dry matter yields of 'Saeyoung' at milk-ripe stages were 47.2 and $15.6MT\;ha^{-1}$, respectively, which was 9% and 4% higher than those of the check. The crude protein content of 'Saeyoung' was 0.4% lower than 6.8% of the check, while was higher than the check cultivar 'Shinyoung' in neutral detergent fiber, acid detergent fiber. Total digestible nutrients of 'Saeyoung' was also 3% lower than 62.8% of the check cultivar. It showed grain yield of $4.1MT\;ha^{-1}$, which was 11% higher than that of the check. 'Saeyoung' is recommended for fall sowing forage crops in areas in which average daily minimum mean temperatures in January are higher than $-10^{\circ}C$.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.6
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• pp.374-385
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• 2013

Sediment particle motions have been numerically simulated over a sinusoidal ripple. Turbulent boundary layer flows are generated by Large Eddy Simulation, and the sediment particle motions are simulated using Lagrangian particle tracking method. Two unsteady flow conditions are used in the experiment by employing two different wave amplitudes while keeping other conditions such as wave period same. As expected, the amount of suspended sediment particles is clearly dependent on the wave amplitude as it is increasing with increasing flow intensity. However, it is also observed that the pattern of suspension may be different as well due to the only different condition caused by wave amplitude. Specially, the time of maximum sediment suspension within the wave period is not coincident between the two cases because sediment suspension is strongly affected by the existence of turbulent eddies that are formed at different times over the ripple between the two cases as well. The role of these turbulent eddies on sediment suspension is important as it is also confirmed in previous researches. However, it is also found the time of these eddies' formation may also dependent on the wave amplitude over rippled beds. Therefore, it has been proved that various flow as well as geometric conditions under waves has to be considered in order to have better understanding on the sediment suspension process over ripples. In addition, it is found that high turbulent energy and strong upward flow velocities occur during the time of eddy formation, which also supports high suspension rate at these time steps. The results indicate that the relationship between the structure of flows and bedforms has to be carefully examined in studying sediment suspension at coastal regions.