• Journal of Wetlands Research
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• v.13 no.3
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• pp.707-720
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• 2011

For the lake case, the detention phenomenon of water body occurs and stays for a long time. Especially, following the layer of water depth direction, the lake body and water quality problems are different from the water quality of river. So according to time, the stream and water quality can be simulated by the 3-Dimensional Model, which can divide water layer for reservoir or lake. The water quality simulation result will become more reliability. For this study, the 3-Dimension Model - EFDC was used to simulate water quality of Unam reservoir in the Sumjin Dam. The HEC-GeoHMS and HEC-HMS Rainfall - Runoff Model based on GIS were used to estimate long-term runoff, and input data was constructed to the observed water level, meteorological data, water temperature, T-N and T-P. In order to apply the EFDC model, water depth was divided into 3 layers and 5,634 grids were extracted. After constructing the grid net, the water quality change of Unam reservoir in time and space was simulated. Overall, long term runoff simulation reflected the actual observed runoff well, through the water quality simulation, according to the pollution factors, the behavior characteristics can be checked, and the simulated water quality can be properly reflected. The function of EFDC has been confirmed, which water quality can be properly simulated. In the near future, to establish countermeasures for Intake Facilities of Watershed and Management, this support which some basic tools can be applied is in expectation.

• The KIPS Transactions:PartC
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• v.17C no.6
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• pp.441-450
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• 2010

Recently, a lot of interest is increased in sensor network which gathers various data through many sensor nodes deployed in wired and wireless network environment. However, because of the limitation in memory, computation, and energy of the sensor nodes, security problem is very important issue. In sensor network, not only the security problem, but also computing power should be seriously considered. In this paper, considering these characteristics, we make the sensor network consist of normal sensor nodes and clusterheaders with enough space and computing power, and propose a group key rekeying scheme adopting PCGR(Predistribution and local Collaborationbased Group Rekeying) for secure group communication. In our proposal, we enhance the security by minimizing the risk to safety of the entire network through verifying the new key value from clusterheader by sensor nodes. That is, to update the group keys, clusterheaders confirm sensor nodes through verifying the information from sensor nodes and send the new group keys back to authentic member nodes. The group keys sent back by the clusterheaders are verified again by sensor nodes. Through this mutual authentication, we can check if clusterheaders are compromised or not. Qualnet simulation result shows that our scheme not only guarantees secure group key rekeying but also decreasesstorage and communication overhead.

• Tunnel and Underground Space
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• v.28 no.3
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• pp.258-276
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• 2018

The accurate and quantitative ground information on the hydraulic conductivity characteristics of rock mass is one of the key factors for evaluation of the hydro-geological behaviour of rock mass around an excavated opening under high water pressure. For tunnel and rock structures in seabed, where the sea acts as an infinite source of water, its importance become greater with increasing construction depth below sea level. In this study, to improve the problems related with poor system configuration and incorrect data acquisition of previous hydraulic packer testing equipment, we newly developed an integrated main frame and 30 bar level waterproof downhole sonde apparatus, which were optimized for deep hydraulic packer test in seabed rock mass. Integration of individual test equipment into one frame allows safe and efficient field testing work on a narrow offshore drilling platform. For the integrated type main frame, it is possible to make precise stepwise control of downhole net injection pressure at intervals of $2.0kg_f/cm^2$ or less with dual hydraulic oil volume controller. To ensure the system performance and the operational stability of the prototype mainframe and downhole sonde apparatus, the field feasibility tests were completed in two research boreholes, and using the developed apparatus, the REV(Representative Elementary Volume) scale deep hydraulic packer tests were successfully carried out at a borehole located in the basalt region, Jeju. In this paper, the characteristics of the new testing apparatus are briefly introduced and also some results from the laboratory and in-situ performance tests are shown.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.168-175
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• 2020

Recently, there has been an increasing need to expand the supply of renewable energy as a solution to greenhouse gas emissions. Therefore, as a measure to promote domestic renewable energy investment and gradual expansion, this study analyzed the investment value of renewable energy projects utilizing the unoccupied spaces of public enterprise's facilities and presented a strategic decision-making framework to support efficient national land development and government measures. The NPV was estimated to be 286 million won if the expansion of the facility was not considered, but it is reasonable to postpone the expansion decision because the value of -130 million won was calculated if the expansion was considered. On the other hand, the real-option value was estimated to be 444 million won, taking SMP uncertainty, expansion, and abandonment options into account, and an additional value of 288 million won was calculated from an analysis of the expansion project using the existing NPV analysis.

• Journal of environmental and Sanitary engineering
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• v.15 no.2
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• pp.18-26
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• 2000

In order to improve the quality of Kamju(sikhae), Korean traditional sweat fermentated rice drink, Kamju made with laboratory fermenting from both covered barley malt and that added to commercial $\alpha-amylase$ and commercial sikhae can were investigated and analyzed ad follows 1. The amylase activities in L-malt(laboraory made malt), C-malt(commercial malt) were 25,065 units, 20,498 units at $60^{\circ}C$ and when heating at $60^{\circ}C$ for one hour their heat stability was getting lower and while at $70^{\circ}C$ after 2 hours both their heat stability was under 21%. 2. The external appearance, of all samples, in beating test, flipper, springer and leaker test were excellent and good valued. On the open test of sample can, head space was 7.9~9.0mm, net weight 247~250g, 432~435g, pH 4.96-5.76, Brix 13.2~14.0 and vacuum degree was 29~35cmHg. 3. The sucrose content of sample 1~5 was 8,57~10.01% highest ammount than sample 6(0.91%) 7(0.43%) and maltose content of sample 1~5 was 0.65~1.41% lower than 6 was 7.91% and 7 was 8,36%. The good traditional flavor texture and saccharides components content of glucose of sample 1~5 was 1.09~1.51, 6(3.86%), 7(3.97%), fructose content of sample 1~5 was 0.45~0.95%, 6(2.76%), 7(2.81%), maltotriose and raffinose of sample 1~5 were 0.04~0.291, 6(0.61%), 7(2.81%), and solid content of sample 1~5(3.1~3.8) was lower than 6(10.25%), 7(10.09%). 4. The result of sensory test as measured as lemone yellow of sample 6 and milky of sample 7, and weetness, flavor, color, traditional texture and sensory value for sample 1~5(3.1~3.8) was lower degree than that for 6(4.5), 7(4.0). 5. Among the heavy metals analyzed from sample cans, tin, iron and lead content for sample 1~5 were 31.95~36.71ppm, 5.84~6.39ppm and 0.075~0.09ppm while their content of sample 6.7, tin, 32.91ppm, 32.87ppm, iron 5.51ppm, 5.41ppm and lead, 0.074ppm, 0.079ppm.

• Research in Plant Disease
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• v.15 no.1
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• pp.1-7
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• 2009

Viruses diagnosed on crops including rice plants from farmers or agricultural extension agencies cover the country were 11 species including Broad bean wilt virus 2 (BBWV2) in 2008. Tomato spotted wilt virus (TSWV) was the most important virus having the detection rate of 22.9%. Two viruses of Tomato yellow leaf curl virus (TYLCV) and Tobacco leaf curl virus (TLCV) inducing leaf yellow and curl diseases on tomatoes were occurred newly with the detection rate of 12.2% and 4.0%, respectively, in 2008. Rice stripe virus (RSV) was occurred on 869.5 ha mainly at Jindo and Haenam areas in Jeollanamdo province. At Jindo area, 12 plots were damaged severely with the infected hill rate of 83.8%. At the main production area of oriental melon at Seongju, almost all fruits from whole sale market at Seongju were infected with Cucumber green mottle mosaic virus (CGMMV) as the detection rate of 87%. The areas occurred TSWV in Korea were 25 totally from 2003 including 7 areas newly reported in 2008 including Naju in Jeoallanamdo. TSWV could be reduced as 0.1 % from 5.3% by covering insect proof net in vinyl house after chemical soil sterilization. Tomato yellow leaf curl disease was occurred on April in 2008 at Tongyoung area in Kyeongsangnamdo, and detected continuously at 13 areas, 7 in Kyeongsangnamdo, 4 in Jeollabukdo and 2 in Jejudo. Potato spindle tuber viroid (PSTVd) was occurred abruptly in a confined space of a civil breeding greenhouse and a cultivar evaluation field followed by disuse 17.4 M/T of potato tubers. No PSTVd was detected at 17 fields cultivated the related potatoes to the bred company by RT-PCR.

• Journal of Labour Economics
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• v.24 no.1
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• pp.97-124
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• 2001

Co-residence is a type of intergenerational private transfers of resources: money, time and space. Adult daughters and their elderly parents decide to co-reside, depending on their utility levels before and after co-residence that mainly depend on the health status of the elderly. Therefore, co-residence implies positive net benefits to both parties in the sense that, when they co-reside, elderly parents share childcare and adult daughter provide elderly care. In other words, formal (paid) care can be substituted with informal (unpaid) one. Both marriage and giving births are considered as the major obstacles to labor market attachment of women who bear burdens of home production and childcare. Co-residence can be a solution for married women to avoid career interruption by sharing burdens with their elderly parents. However, most previous studies using the U.S. data on intergenerational private transfers focused on elderly care and have concluded that they reduce government expenditures associated with public subsidies to the elderly. This study focuses on adult daughters and it examines effects of co-residence on labor supply of married women in Korea, who face limited formal childcare programs in terms of both quantity and quality. It applies the Tobit model of married women's labor supply to the data from the Second Wave of the Korean Labor and Income Panel Survey( 1999), in order to investigate effects of co-residence and the work and health status of the co-residing elderly as well as their own health status. Four specifications of the empirical model are tested that each includes co-residence with elderly parents, their gender, or their work and health status. Estimation results show that co-residence, co-residence with female elderly, and co-residence with not-working female elderly have significant positive effects on labor supply of married women while poor health status of co-residing female elderly does not bring about any negative effects. However, co-residence with male elderly, regardless of their work and health status, has no significant effect The results indicate that co-residence is closely related to sharing of home production among female elderly and adult daughters who are married and, through intergenerational private transfers of resources in terms of time, it helps women avoid career interruption.

• Journal of the Korean Geographical Society
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• v.48 no.6
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• pp.897-913
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• 2013

The main purpose of the paper is to examine the spatial characteristics of school choice through residential mobility by conducting a correlation analysis on the relationships between the middle schools' entrance rates to special high schools and the elementary schools' net transfer rates. Analyses are done at both the individual school level and the school catchment area level. Prior to the calculation, the two variables involved in the correlation analysis are transformed via a standardization equation, and the standardized scores are mapped and explored. Both the global and local correlation analyses are done for the standardized variables. Main findings are twofold. First, the global correlation analysis reports that there exists a statistically significant correlation between the two variables at both the analytical levels. Second, albeit the prominent positive correlation at the global level, the local analysis reveals the existence of a considerable level of spatial heterogeneity in terms of bivariate association. While several school catchment areas with very high local correlation coefficients (the HH association type) are popped up, other areas with various types of bivariate association including ones even opposite to the global trend are also observed.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.394-402
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• 2010

The objective of this study was to identify the effects of ozone on the two species in controlled environment. $Sedum$ $kamtschaticum$ and $Hosta$ $longipes$ were exposed in both control and ozone chamber to investigate photosynthesis, antioxidant enzyme activity, visible damage, the number and the size of stomata and the plastogloubuli. Ozone was fumigated in the concentration of $200{\mu}g{\cdot}kg^{-1}$ for 8 hours in a day (from 08:00 AM to 04:00 PM). Firstly, net photosynthesis of two species was decreased after ozone fumigation. Secondly, glutathione reductase activities showed significant difference between control and ozone treatment. Thirdly, visible symptoms of leaves were expressed such as chlorosis, necrosis and decoloration. Also, the size of stoma was significantly decreased in ozone-exposed plants. Furthermore, the intercellular space of $Hosta$ $longipes$ showed increased phenomenon because the mesophyll was collapsed. The number and the size of the plastogloubuli were significantly larger in ozone stress.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.1
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• pp.47-59
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• 2023

Due to climate change and urbanization, abnormally high temperatures and heat waves are expected to increase in urban and deteriorate thermal comfort. Planting of street trees and changing the albedo of urban surfaces are the strategies for mitigating the thermal environment of urban, and both of these strategies affect the exposure and blocking of radiative fluxes to pedestrians. After measuring the shortwave and longwave radiation according to the ground surface with different albedo and the presence of street trees using the CNR4 net radiometer, this study analyzed the relationship between this two strategies in terms of thermal environment mitigation by calculating the MRT(Mean Radiant Temperature) of each environment. As a result of comparing the difference between the downward shortwave radiation measured under the right tree and at the control, the shortwave radiation blocking effect of the tree increased as the downward shortwave radiation increased. During daytime hours (from 11 am to 3 pm), the MRT difference caused by the albedo difference(The albedo of the surfaces are 0.479 and 0.131, respectively.) on surfaces with no tree is approximately 3.58℃. When tree is present, the MRT difference caused by the albedo difference is approximately 0.49℃. In addition, in the case of the light-colored ground surface with high albedo, the surface temperature was low and the range of temperature change was lower than the surrounding surface with low albedo. This result shows that the urban thermal environment can be midigate through the planting of street trees, and that the ground surface with high albedo can be considered for short pedestrians. These results can be utilized in planning street and open space in urban by choosing surfaces with high albedo along with the shading effect of vegetation, considering the use by various users.