• Journal of the korean society of oceanography
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• v.36 no.1
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• pp.1-8
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• 2001

An in-situ four-electrode contact resistivity probe system was designed, and field-tested in submarine sediments. Seismic survey was also performed to support and compare the results of electric survey. The probe was designed to be driven to selected depths below the seafloor using a Vibracore system. The four insulated electrodes were, spaced equidistant across the wedge, were extended beyond the probe tip to minimize effects of sediment disturbance by the wedge insertion. In-situ measurements of resistivity were recorded on board by precision electronic equipment consisting of signal generators and processors, and by temperature-monitoring systems. Overall limits of Uncertainty at respective depths below the seafloor are up to ${\pm}$10 of the measured values. Best estimates of conductivity are considered to be ${\pm}$3 percent of the reported values. Resistivity measurements were made at six sites in carbonate sediments to a maximum depth of penetration of about 5 m. Average values of conductivity range between 0.88 and 1.21 mho/m. The results show the seabed is composed of alternating layers of relatively high-conductivity material (0.8 to 1.4 mho/m) in thicknesses of more or less one meter and layers about 30 cm thick having relatively low conductivities (0.4 to 0.8 mho/m).

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.1
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• pp.31-44
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• 1989

In the vinyl house cultivation, the water consumption, evapotnanspirafion ratio, growth condifion by the growing stages and yields of tomato and cucumber were investigated when they cultivated by nutriculture, rice hull charcoal culture and NFF culture. The results obtained are summarized as follows: 1. The mean air temperature in the vinyl house during the experimental perica j was 1.9$^{\circ}$C higher than the outdoor air temperature, the rrnocirnum and minimum air temperature in the vinyl house was 4.6C and 1.7$^{\circ}$C higher than the outdoor temperature, respectively, and the mean daily evaporation in the vinyl house during the experimental period was 4.3rnm that is 02rnrn more than the outdoor evaporation 2. In the tomato cultivation, the growth of rice hull charcoal culture was the best among the three methods, and the growth of NFT culture and nutriculture were worse than the soil cultivation which is standard, and among the nutriculture, the growth of EC 1.3m.mho plot was the best. 3. In the cucumber cultivation, the growth of rice hull charcoal culture was the best, and while the growth condition of NFT culture was worse than the standard soil cultivation, the growth of nutriculture was better than the standard soil cultivation, and the growth of EC 1.3m.mho plot was the highest among the different treatments in the nutriculture. 4. In the tomato cultivation, the total water consumption of rice hull charcoal culture plot was 1107.5rnm which is the highest amount among the three methods, and in the nutriculture, the total water consumption of EC 1.3m.mho plot was 22lAmm which is the highest among the three different treatments. 5. In the cucumber cultivation, the total water consumption of rice hull charcoal culture was 11762rnm which is the highest, and the total water consumption of EC 1.3m.mho plot was 284.9rnm which is more than the 278.9mm of EC 1.Smmho plot and 262.9mm of EC 1.7rnmho plot. 6. The crop coefficient(Kc) of tomato was 0.82 in NFT culture, 4.67 in rice hull charcoar culture and 0.86~0.91 in nutriculture. 7. The crop coefficient(Kc) of cucumber was higher than tomato as 1.13 in NFT culture, 520 in rice hull charcoal culture and 1.08~1.19 in nutriculture. 8. The evapotranspiration ratio in the mid and late season were higher than the beginning and elongation stage, and the average evaportranspiration ratio of tomato and cucumber was 3.81 and 424, respectively, in the rice hull charcoal culture plot. 9. In the tomato cultivation, the total yield per plant of rice bull charcoal culture was 1443.Og which is the highest, and in the nutriculture, their yields were worse because of the damage of downy nidew disease. 10. In the cucumber cultivation, the total yield per plant of rice hull charcoal culture was 1965.7g which is the highest, and while the yield of NFT culture was ahout 25% lower than the stadard soil cultivation, the yield of nutriculture was higher than the standard soil cultivation, and among the treatments in the nutriculture, the yield of EC 1.3m.mho plot was the highest.

• Bulletin of the Korean Chemical Society
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• v.18 no.1
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• pp.120-121
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• 1997

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.368-372
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• 2014

The most widely used scheme for detecting loss of excitation on generator is used to sense apparent impedance from generator terminals. This paper presents loss of excitation algorithm using DFT filter based negative offset mho elements for generator field protection. It's algorithm includes two negative mho characteristics looking in the generator. The generator control system was modeled by PSCAD/EMTDC software, and then the proposed algorithm was tested by the collecting relaying signals from selected the generator model. From simulation results, the loss of excitation algorithm can be used to field protection for generator.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.322-326
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• 2014

Recently, the LOE(loss of excitation) incidents are occurred in domestic synchronous generator frequently, the synchronous generator protection system has been much attention for the LOE protection of the incidents that threats synchronous generators and power systems. This paper was showed the characteristics and practices of distance relay that widely used LOE protection relaying in generator. Firstly, the operating characteristics and the impedance locus for LOE of the generator protection were introduced. Even if the conventional simulation program is used for modeling, but it is difficult to implement a LOE modeling and simulation of synchronous generator. So, the LOE relay operation data collected from thermal power plant and nuclear power plant in real fields were analyzed. By reviewing the applications of GE Mho relays, the reliability of LOE for synchronous generator protection in domestic were improved.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.8
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• pp.1326-1333
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• 2016

It is important to clear the fault and prevent resulting in damage to power system. Although the frequency of generator internal fault is relatively low, it can lead to incalculable damage to power system as well as generator. Especially, loss of field on generator can cause the generator to lose synchronism for a short time if it is not removed promptly. Therefore, it is needed to conduct research on loss of field relay for detecting or clearing the loss of field. However, the setting of the relay may vary in generator operator or engineer, and the relay is not coordinated well with other elements associated with loss of field. In this paper, we address specifically the coordination of positive offset mho loss of field relay which is one of the protection schemes for loss of field. Computer simulations are performed by using ElectroMagnetic Transients Program-Restructured Version (EMTP-RV) based on actual data.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.2
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• pp.169-175
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• 1986

This study was carried out to evaluate the water quality of spring waters in Pusan area (see Fig. 1). In this experiment, one hundred and forty water samples were collected at 20 stations from July to December 1985. Range and mean value of constituents of the samples were as follows ; pH 6.2-8.2, 7.07 ; water temperature $4.0-23.5^{\circ}C,\;15.9^{\circ}C$ ; electrical conductivity $0.228{\times}10^{2}-2.125{\times}10^2{\mu}{\mho}/cm,\;0.860{\times}10^2{\mu}{\mho}/cm$; chloride ion 3.28-19.3mg/l, 6.81mg/l ; nitrite-nitrogen ND-0.221 mg/l, 0.017mg/l ; nitrate-nitrogen ND-6.779mg/l, 0.877 mg/l ; phosphate-phosphorus ND-0.105mg/l, 0.021mg/l ; silicate-silicious 2.12-22.70mg/l, 9.04mg/l, respectively. Especially, electrical conductivity, chloride ion, nitrite-nitrogen, nitrate-nitrogen, and silicate-silicious of the station 11 (Millakdong) were higher than those of others as $1.815{\times}10^2{\mu}{\mho}/cm$, 13.5mg/l, 0.076mg/l, 4.772mg/l and 14.07mg/l. Range and geometric mean value of total coliform and fecal coliform MPN's of the samples were 0-1,500/100ml, 13-470/100ml and 0-460/100ml, 2-32/100ml. Composition of coliform was $26.37\%$ Escherichia coli group, $21.98\%$ Citrobacter freundii group, $37.36%$ Entrobacter aerogenes group and $14.29\%$ others.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.6
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• pp.538-544
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• 1985

This study was carried cut to evaluate the water quality of spring waters in Pusan area(see Fig. 1). In this experiment, twenty-five water samples were collected from 5 stations from December 1983 to August 1984. Range and mean values of constituents of the samples are as follows: pH $5.80{\sim}7.25$, 6.60; water temperature $6.0{\sim}23.0^{\circ}C,\;12.9^{\circ}C$; total residue $33.0{\sim}325mg/l$, 121.2mg/l; alkalinity $4.75{\sim}51.6mg/l$, 24.1mg/l; hardness $9.47{\sim}85.0mg/l$, 30.3mg/l; electrical conductivity $0.495{\sim}2.750{\times}^2{mu}{\mho}/cm,\;1.239{\times}10^2{\mu}{\mho}/cm$;turbidity $0.54{\sim}7.80$NTU, 2.04NTU; $KMnO_4$ consumed $0.51{\sim}8.47mg/l$, 1.96mg/l; chloride ion $4.91{\sim}36.0mg/l$, 12.55mg/l; fluoride ion ND-0.30ppm, 0.08ppm; nitrate-nitrogen ND-8.94mg/l, 1.94m:g/l; nitrite-nirogen ND-0.10mg/l, 0.03mg/l; ammonia-nitrogen ND-0.16mg/l, 0.03mg/l: phosphate-phosphorus ND-0.09mg/l, 0.03mg/l; silicate-silicious $0.42{\sim}22.7ng/l$, 7.96mg/l; copper ND-10.5ppb, 2.46ppb; lead ND-22.7ppb, 3.54ppb; zinc ND-103ppb, 21.33ppb; iron $20.3{\sim}2,800ppb$, 801.72ppb, respectively. Arsenic, cyan, cadmium, manganese, mercury, chrome and phenol were not detected. Total residue, electrical conductivity, turbidity and chloride ion of station 1 (Milrakdong) were higher than others as 178.1mg/l, $2.127{\times}10^2{\mu}{\mho}/cm$, 3.16NTU and 16.32mg/l. The concentration of silicious had a great influence on precipitation. The concentration of fluoride ion of spring waters was lower as 0.08ppm than the criterion for drinking water as 1ppm, while iron was exceed 2.7 times as 801.72ppb.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.3
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• pp.103-108
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• 1980

The contents of inorganic conservative constituents in Nagdong River water were determined at Mulgeum where the intake station for Busan city water is located. Samples were taken at intervals of one hour from 7 a.m. to 7 p.m. at spring and neap tides of every month from January 1979 to April 1980. Annual ranges and means of the chemical constituents were as follows: electrical conductivity $99-912\mu\mho/cm,\;200\mu\mho/cm;$ chlorides 6.0-256 ppm, 17.2 ppm; sulfates 4.1-37.9 ppm, 23.5 ppm; calcium 4.2-28 ppm, 13 ppm; magnesium 2.2-23 ppm, 5.6 ppm; sodium 5,0-126 ppm, 14 ppm; and potassium 1.2-10.8 ppm, 2.6 ppm respectively. At several times in this period, the concentrations of chloride ion exceeded 150 ppm that is the criteria for drinking water. The chloride ion concentration was higher at spring tides than that at neap tides and the contents of inorganic conservative constituents were higher in winter than those in summer. The chloride ion concentration showed the highest value at Mulgeum about 4 hors after the high water in Busan harbour.

• East Asian mathematical journal
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• v.22 no.2
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• pp.195-205
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• 2006

Using the notion of anti fuzzy points and its besideness to and non-quasi-coincidence with a fuzzy set, new concepts of an anti fuzzy subgroup are introduced and their inter-relations are investigated.