• Journal of the korean society of oceanography
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• v.39 no.3
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• pp.197-206
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• 2004

Mussel, Mytilus galloprovincialis, was transplanted reciprocally between contaminated site (St. STP) and relatively less contaminated site (St. UB) in Onsan Bay, Korea in order to estimate heavy metal accumulation and release. Transplanted and indigenous mussels were collected 8 times over 108 days deployment at both sites and analyzed for Cd, Cu, Pb and Zn using ICP/MS. Cu and Zn concentration did not show any significant differences between transplanted and indigenous mussels throughout the experiment period, although dissolved Cu and Zn concentrations in seawater were significantly higher at contaminated site. Pb accumulated rapidly, while Cd did not show any accumulation in the mussels transplanted from St. UB to St. STP. These accumulation patterns might reflect the variation of dissolved metal concentration; dissolved Pb concentration was significantly higher in St. STP than St. UB, while dissolved Cd concentration was similar between both sites throughout this experiment. Release of Cd and Pb in the mussels transplanted from St. STP to St. UB was not significant during the transplantation period. The levels and variation of Pb and Cd concentrations in mussels transplanted from St. STP to St. UB were similar to those in the indigenous mussels at St. STP throughout the period. Therefore, Cd and Pb accumulated in indigenous mussels may indicate the integrated metals throughout their lives, not responding to the present status of seawater because the release of accumulated metals in mussels occurs very slowly when the seawater metal levels are lowered. On the other hand, since the transplanted mussels can respond immediately to the levels of metals in seawater, it may be suggested that the present status of heavy metals in seawater can be only acquired from the metal levels of mussels transplanted from clean environments.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.9
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• pp.46-53
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• 2007

The link-fault recovery in the normal Ethernet bridged networks has relied on the Spanning Tree Protocol(STP) or Rapid STP. However, STP can not offer fast error recovery which is needed real-time services such as aircraft. In this paper, we compare automatic protection switching(APS) providing fault-tolerant function in the BcN back bone system with Avionic Full Duplex Switched Ethernet(AFDX) which is recently equipped in the A380 for Airbone Databuses. Also, we propose a link-bypass scheme for improving fault-tolerant performance of the AFDX by connecting switches and bypass fault section when a fault is originated on the link. For comparing and verifying the performance of proposed scheme, we simulated Ethernet, AFDX, APS and proposed AFDX with link-bypass scheme using NS-2. The proposed AFDX with link-bypass scheme can be applied to aircrafts, BcN backbone networks and industrial automatic networks.

• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.778-784
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• 2009

The purpose of this study is to figure out the differences of the inflow rates of Sewage Treatment Plants (STP), invested by public fund or public-private partnership (PPP). This paper finds that the average ratio of sewage inflow according to facility capacities (medium and small scale STP) was either nearly below 30% or above 100% in the first year. As the size of STP increased, there was decrease in the accuracy of demand assumption. This was because the operation time when the ratio of sewage inflow was uniform was different according to the size of STP, whereby the time was short when the STP were small. The design average ratio of sewage inflow was 10% larger than the real average ratio; this was considered overdesigned. In the case of a plant built by the PPP scheme, the average ratio of inflow of the STP before an abolition of MRG was larger than after the abolition of MRG. This may be explained by moral hazard from too much reliance on MRG. After the abolition of MRG, the demand risk of PPP was shifted from a PPP project to a conventional project.

• Analytical Science and Technology
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• v.9 no.4
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• pp.345-354
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• 1996

Algal(II) Multidentate N, O-Schiff base ligands, such as bis(salicylaldehyde) ethylenediimine(SED), bis(salicylaldehyde) propylenediimine(SPD), bis(salicylaldehyde) diethylenetriimine(SDT), bis (salicylaldehyde) triethylenetetraimine(STT) and bis(salicyl-aldehyde)tetraethylenepentaimine(STP) were prepared. Stepwise proton dissociation constants of the Schiff base were measured potentiometrically in ethanol and a mixture of 70% dioxane and 30% $H_2O$. The stability constants of copper(II)-Schiff base complexes were in the order of Cu(II)-SPD${\leq}$Cu(II)-SED~STT${\leq}$Cu(II)-STP. Oxidation-reduction process of the Cu(II)-Schiff base complexes was involved with one-electron reaction.

• Journal of Korean Society of Water Science and Technology
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• v.26 no.6
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• pp.53-59
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• 2018

Water pollution is drastically increasing day by day, because of the enhancement in use of livestock, urban sewage detergents and fertilizers. Moreover increase in concentration of phosphorous and nitrogen contained in sewage, leads to green tide problem in the rivers and causes marine pollution. For this problem to solve, several technologies are being researched and developed. Among them, this experiment is a study on Bench-scale STP based on internationally certified sewage treatment equipment by MEPC. 227(64) of IMO. The purpose of this study is to compare the biological treatment efficiency of phosphorus of Bench-scale STP. The ratio of C : N : P was set to 10 : 5 : 3 and 10 : 3 : 1 as the operating conditions. And the operation cycle was set to anoxic(mixed) 70 min - aeration 50 min (70-50), anoxic(mixed) 90 min - aeration 60 min (90-60). As a result, the phosphorous treatment efficiency was 88% at average, and the treatment efficiency was steady at 90-60 better than 70-50. The efficiency of the bench-scale STP has been verified through this experiment and additional experiments are required to derive the optimal operating conditions.

• KEPCO Journal on Electric Power and Energy
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• v.7 no.1
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• pp.51-52
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• 2021

지상변압기는 수용가에 직접적으로 전력을 공급하는 역할을 수행하며 저압 선로의 고장으로부터 계통을 보호하기 위한 보호장치를 구비한다. 본 기술지원은 지상변압기의 STP 미동작에 따른 화재원인을 분석하고 적정동작범위를 제안한다.

• Korean Journal of Ecology and Environment
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• v.34 no.2 s.94
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• pp.126-132
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• 2001

Urbanization and population increase result in the construction of STPs (Sewage Treatment Plants). Discharge from STPs greatly influences on the water quality in the stream which receives discharges. The decision of STP location should be considered with the discharge capacity of STP and self-purification of river in the water quality perspectively. In this study, a change of dissolved oxygen (DO) in a river being affected by STP discharge was simulated by the STELLA model. Minimum DO was 4.98 ppm in 42.6 km downstream of STP. Approximately, it takes 8days to recover the DO by the self-purification and this location is 340 km down-stream from the STP. If the model run for the consideration of the self-purification without phytoplankton algorithms, minimum DO was 4.92 ppm. It took 0.25 day longer to be the minimum DO than that with the phytoplankton functions. Without the phytoplankton algorithm, it took 11days to recover the DO. This proves the importance of phytoplankton in the self-purification processes. Additionally, the effect of adjacent STP discharge should be considered in the construction of new STP.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.6
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• pp.647-655
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• 2008

Sewer Rehabilitation Project (SRP) is planed, designed and constructed to perform its intended performance as sewerage delivery systems. Recently, a subject of performance evaluation methodology development for SRP has become a great deal of concern among researchers in Korea. From the view point of Sewage Treatment Plant (STP), however, the estimation of improvement efficiency for SRP is in lack of reliability due to the fact that affections for the treatment efficiency and operating condition are not reflected on SRP design and construction. In this study, statistical methodology was used in the analysis of data, which are taken during 1,186 days ($1^{st}$ Jan. 2005 - $31^{th}$ Mar. 2008) from the influent, effluent and operating conditions of full-scale STP($25,000m^3/d$). Then the effect of SRP on the influent characteristics and operating conditions changing was compared and evaluated. Results from the statistical evaluation show that SRP causes characteristic changes in influent and exerts a significant effect especially on the performance of STP.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.5
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• pp.719-726
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• 1999

Multiconductor transmission line(MTL) equations are solved by FDTD method to examine the coupling between incident electromagnetic fields and multiconductor transmission lines. The measurement of induced voltages on UTP Category 5 and STP Category 5 cables which are used as LAN cables is carried out using a TEM cell where uniform and strong TEM fields can be established. The comparison between measured and simulated results shows good agreement. It is also found that grounding of shield foil at both terminations and small grounding resistance give good shielding effects for STP Category 5.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.123-126
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• 2005

STP gets to have different network performance, depending on the configuration method of topology. Accordingly, for efficient network environment, it is necessary to make the optimum topology. This paper proposed a way to make the optimum topology for construction of efficient network among switches on ethernet: the optimum topology was made by calculating the time the switches in the same domain receive the frame transmitted from the root switch, using a mathematical model. And it analyzed the performance of the topology depending on the location of the root switch. As a result of analyzing the performance, this study came to the conclusion that it would be effective to locate the root switch in the center of the square network.