• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.257-264
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• 2006

In order to evaluate the application of Algae Online Analyzer (AOA), an instrument of automatic measurement of chlorophyll a concentration, was tested and compared with the acetone extraction method on the basis of microscopic counting of phytoplankton in field water (Paltang Reservoir). We simultaneously conducted AOA operation and extraction method with the same water sample, to compare both results of chlorophyll a measurement. Phytoplankton were enumerated by inverted microscope with the Sedgwick-Rafter chamber, and classified into the genus or species. According to the AOA measurement, the diatom most (83.6%) strongly contributed to the total chlorophyll a concentration, followed by chlorophyceae> cyanophyceae>cryptophyceae. Overall, the results of both AOA and extraction method showed a similar trend and significant correlation (r=0.87, n=302, p<0.001), however, there were some differences according to the season and species. In particular, the relationship between AOA Chl-a density of the diatom (r=0.73, p=0.010) and cyrptophyceae (.=0.83, p=0.00154) were siginificant, while chlorophyceae (r= -0.13) and cyanophyceae (r= -0.16) showed no clear relationship during the study period. Although we can not fully understand why there was difference between both mothods, AOA application for alarming algal bloom and water quality management during the algal bloom appears to be very relevant. However, the further study or technical upgrade of AOA measurement is required, especially in the case of low density of phytoplankton or species-specific measurement.

• Korean Journal of Ecology and Environment
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• v.43 no.4
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• pp.471-476
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• 2010

Monthly up-river discharge in the riverine zone analysis resulted in large interannual variations and differences in calcium ($Ca^{2+}$), bicarbonate ($HCO_3^-$), and cations in the lacustrine zone (Lz) of Daecheong Reservoir during the wet year (Wy, 1993) vs. dry year (Dy, 1994). Total up-river discharge in the Wy was four times that of the Dy, and the up-river discharge in July~August of the Wy was eight times greater than that of same period of Dy. Annual water retention time in the Lz showed large difference between the two years. Water residence time (WRT) was minimum when the up-river discharge peaked, whereas the WRT was maximum when the up-river discharge was at minimal condition. This peak discharge from the up-river on early July reduced residence time in the Lz on mid-July~late July. Monthly pattern, based on data of May~November, was similar between the two years, but, but mean retention time in the Wy was 50 days shorter than in the Dy. Such hydrology, up-river discharge, and WRT reduced $Ca^{2+}$, $HCO_3^-$, and cations in the Lz. At low up-river discharge in Wy during April~May, the cation content of Ca+Mg+Na+K averaged 1.17meq $L^{-1}$ (range=1.09-1.26meq $L^{-1}$), but as the up-river discharge increased suddenly, the values decreased. Seasonal fluctuations of $Ca^{2+}$ showed exactly same pattern with bicarbonate ion of $HCO_3^-$. The minimum $Ca^{2+}$ (0.03meq $L^{-1}$) was occurred in the early August of wet year and coincided with the minimum $HCO_3^-$. These results suggest that the magnitude of variation in $Ca^{2+}$, bicarbonate, and cations in the lacustrine zone is directly determined by the peak magnitude of up-river discharge. The magnitude of up-river discharge determined water retention time and the magnitude of ionic dilution in the lacustrine zone, resulting in functional changes of the ecosystem.

• Korean Journal of Health Education and Promotion
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• v.11 no.1
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• pp.43-56
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• 1994

Although the officially confirmed incidence of the acquired immune deficiency syndrome(AIDS) has remained low thus far in Korea, the progression of the pandemic has been rapid, concerned about an eventual increase in transmission. Until a vaccine or cure is found, public information and education remain an important weapon against AIDS. For the year 2000, the current WHO projection is that there will be a cumulative total of 40 million HIV infections in man, woman and children, of which more than 90％ will be in the developing countries. The incerased mortality among adults and children has raised concerns that AIDS may become so devastaing as to reverse positive population growth rates and wipe out entire population. In order to plan for the rising incidence of patient with AIDS, an assessment of AIDS-related cognition and behavior, attitude of the recognized high-risk groups is necessary. Considering that undergraduates have sexuality active and more oriented toward sexual concerns than other ages. Adolescents today are more sexually involved than in the past: The media, including films, music, and television, reinforce sexual concerns by preseating images of highly sexual adolescents. Incidence of both petting and sexual intercourse in higher and occurs at earlier ages, they are important reservoir of AIDS infection. Hence, it has become important to emymerats and describe the knowledge, attitude and behavior of them, I want.. This information will eventually guide the direction of change in public policies and education programs to meet the challenges of AIDS. The objective of this study were to identity Knowledge, Attitude, Experience of Sex and AIDS in Korea. The data were collected by survey at Korean Federation for AIDS Affairs, INC. and J university, K junior college. After October in 1993, surveyed with 507 student during their's college days in Seoul. The questionnaire was designed to provide information on sex and AIDS-related knowledge and attitudes and experience. AIDS-related knowledge was measured by using 26 questions on mode of transmission and AIDS-related attitudes were measured by 7 questions, AIDS-related experience was measured by 5 questions. There were the main dependent variables in our study, In conclusion, students during their university day need to develop AIDS-preventive education programs. Clearly, the many AIDS-prevention educational effort need to be guided by well trained health agents. Financial supports from all sectors (i.e., public and private) of our society are required to achieve that end. Further researches on AIDS-related Knowledge and Attitude and behaviors of undergraduates are needed for the development of comprehensive AIDS prevention programs.

• Geophysics and Geophysical Exploration
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• v.9 no.2
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• pp.155-162
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• 2006

An abnormal seepage flow, which is mainly caused by the piping, is one of the major reasons for embankment dam failure. A leakage detection is therefore a vital part of an embankment dam's monitoring. Resistivity method, which is an efficient tool to detect leakage zones, has been used all over the world for an embankment dam's monitoring. Although the resistivity method gives us very useful information about the leakage problem, there is no more quantitative interpretation than the low resistivity zones in the 2-dimensional resistivity section are regraded simply as the anomalous seepage zones. Recently, resistivity monitoring technique is applied for the detection of leakage zones. However, its interpretation still remains in the stage of presenting the resistivity ratio itself. An increased seepage flow increases a porosity and an increasing porosity decreases the dam's stability. Therefore, the porosity is one of the major factors for an embankment dam's stability. Based on Archie's experimental formula, we try to evaluate a porosity distribution from the resistivity data which is obtained on the dam's crest. We also attempt to represent a procedure to evaluate a safety index of the embankment dam from the resistivity monitoring data.

• Clean Technology
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• v.24 no.2
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• pp.87-98
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• 2018

Phosphorus (P) is an essential and irreplaceable element for all living organisms, and it is widely used as a fertilizer. Unfortunately, it is estimated that phosphate reservoir is depleted within about 100 years. Sewage sludge ash (SSA) is an alternative resource for P recovery because of its high P content. However, SSA cannot be directly used as a fertilizer due to heavy metals in it and low P bioavailability. Thermochemical treatment with Cl donor is known to reduce heavy metal contents and increase P bioavailability of SSA. Literature review on thermochemical technologies of SSA for the reduction of heavy metals and bioavailability enhancement has been carried out to estimate the status of current P recovery technology and to develop strategic future research plan for P recovery. The review showed that $CaCl_2$ and $MgCl_2$ were the most effective Cl donors and reaction temperature (< $1000^{\circ}C$) was the critical operation condition for the reduction. The removal efficiency depends on the species of heavy metals. Thermochemical technology of SSA for P recovery showed the possibility of commercial application in the near future to overcome the coming crisis of human sustainability by P depletion, but it needs cost effectiveness and more ecofriendly process to reduce energy consumption.

• Journal of Life Science
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• v.17 no.1 s.81
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• pp.97-104
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• 2007

Present study aims to investigate the effect of muddy water on gill and kidney tissues and blood components of Opsariichthys uncirostris amurensis in Imha reservoir. As a result of observing the gill tissues in muddy water with light and scanning electron microscopes, the edema, the exfoliation of epithelial cells and fusion of the secondary lamellae were observed. The space between gill lamellae was irregular, and a lots of muddy debris around the secondary lamellae were observed. In case of kidney tissues, the size of glomerulus was smaller and thickness of basal membrane was broader and the empty space in Bowman's capsule was wider than those of the control. The blood cells of O. uncirostris amurensis in muddy water were increased in number. Of the white blood cells, acidophilic granulocytes were highly distributed, and the shapes were irregular. Among the plasma components, the concentration of TP, ALB, A/G ratio, TG, CHOL, and AST were low, whereas that of the inorganic materials was high. Based on the above results, it is considered that muddy water possibly involves in the decrease of respiratory and excretory rates, giving rise to secondary lesion of tissues.

• Spatial Information Research
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• v.11 no.2
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• pp.101-117
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• 2003

High resolution satellite image analysis has been recognized as an effective technique for monitoring local land-cover and atmospheric changes. In this study, a new high resolution map for land-cover was generated using both high-resolution IKONOS image and conventional land-use mapping. Fuzzy classification method was applied to classify land-cover, with minimum operator used as a tool for joint membership functions. In separateness analysis, the values were not great for all bands due to discrepancies in spectral reflectance by seasonal variation. The land-cover map generated in this study revealed that conifer forests and farm land in the ground and tidal flat and beach in the ocean were highly changeable. The kappa coefficient was 0.94% and the overall accuracy of classification was 95.0%, thus suggesting a overall high classification accuracy. Accuracy of classification in each class was generally over 90%, whereas low classification accuracy was obtained for classes of mixed forest, river and reservoir. This may be a result of the changes in classification, e.g. reclassification of paddy field as water area after water storage or mixed use of several classification class due to similar spectral patterns. Seasonal factors should be considered to achieve higher accuracy in classification class. In conclusion, firstly, IKONOS image are used to generated a new improved high resolution land-cover map. Secondly, IKONOS image could serve as useful complementary data for decision making when combined with GIS spatial data to produce land-use map.

• Journal of the Korean earth science society
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• v.38 no.2
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• pp.161-171
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• 2017

Observed ground motions are composed of three factors such as, seismic source, attenuation, and site amplification effect. Among them, the site amplification characteristics should be considered significantly when estimating seismic source and attenuation characteristics with more confidence. The site effect is also necessary when estimating not only seismic hazard in seismic design engineering but also rock mechanical properties. This study uses the method of H/V spectral ratio of observed ground motion between target site and reference site called a reference site method. In addition to using the vertical Fourier spectrum of the reference site, we try out the horizontal Fourier spectrum as a new method in this study. We analyze H/V spectral ratio of six ground motions respectively, observed at four sites close to Yedang Reservoir. We then compare site amplification effects at each site using 3 kinds of seismic energies including S waves, Coda waves energy, and background noise. The results suggest that each site showed similar site amplification patterns in S waves and Coda waves energy. However, the site amplification of background noise shows much different characteristics from those of S waves and Coda wave energy, which suggests that the background noises at each site have their own developing mechanism. Each station shows its own characteristics of specific resonance frequency and site amplification properties in low, high and specific resonance frequency ranges. Comparison of the method used in this study to the others that used different methods can provide us with more information about the dynamic amplification of a site characteristics and site classification.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.4
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• pp.279-286
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• 2018

In the civil works, the measurement of earth-volume is one of the important elements in the estimation of the reasonable construction cost. Related studies mainly used GPS (Global Positioning System) or total station to obtain information on civil work areas. However, these methods are difficult to implement in inaccessible areas. Therefore, the aim of this paper is to use the UAV (Unmanned Aerial Vehicle) to measure the earth-volume. The study area is located in a reservoir construction site in Sangju-si, Gyeongsangbuk-do, Republic of Korea. We compared the earth-volume amounts acquired by UAV-based surveying to ones acquired by total station-based and GPS-based surveying, respectively. In the site, the amount of earth-volume acquired by GPS was $147,286.79m^3$. The amount of earth-volume acquired by total station was $147,286.79m^3$, which is the 96.13% accuracy compared to the GPS-based surveying. The earth-volume obtained by UAV was $143,997.05m^3$ when measured without GCPs (Ground Control Points), $147,251.71m^3$ with 4 GCPs measurement, and $146,963.81m^3$ with 7 GCPs measurement. Compared to the GPS-based surveying, 97.77%, 99.98%, and 99.78% accuracies were obtained from the UAV-based surveying without GCP, 4 GCPs, and 7 GCPs, respectively. Therefore, it can be confirmed that the UAV-based surveying can be used for the earth-volume measurement.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.288-294
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• 2013

Recently, sustainable production of biofuel using algal biomass is being pursued because of its enormous potential. First and foremost, securing superior strains to develop an efficient production system for algal biodiesel through screening or genetic improvement of microalgae is necessary. The genus of Botryococcus is regarded as one of the superior microalgae for biodiesel production due to its ability to accumulate high amounts of lipids and hydrocarbons. However, its low growth rate is a bottleneck for large-scale production and commercialization. The purpose of this study is to obtain indigenous Botryococcus strains which possess high lipid content and biomass productivity. The Botryococcus sp. was isolated from the Seobu Reservoir in Jeju Island and identified as Botryococcus sudeticus J2 by comparative analysis of 18s rRNA gene and ITS regions. The biomass productivity and lipid content of B. sudeticus J2 were 0.116 g $L^{-1}day^{-1}$ and 40.1% of dry wt., respectively. This was higher than the value of B. braunii UTEX 572, which is widely regarded as a superior strain among Botryococcus species. The relatively high growth rate of B. sudeticus J2 was achieved under a light intensity of 240 ${\mu}mol$ photons $m^{-2}s^{-1}$ with ambient air spargingwhen compared to 120 ${\mu}mol$ photons $m^{-2}s^{-1}$ with 2% $CO_2$ supply. In summary, it is likely that the isolated B. sudeticus J2 can be used for the mass cultivation and biodiesel production.