• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.8
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• pp.522-528
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• 2000

In this paper, a static synchronous compensator(STATCOM), which in general compensates reactive power, is proposed in order to balance the unbalanced loads. Reference values for the compensation of the unbalanced loads currents are determined by 3-phase circuit analysis result. Also the STATCOM control unit is designed considering the proposed compensation scheme for the unbalanced loads. As a result, the effectiveness of the STATCOM for balancing the load currents is verified by computer simulations.

• Textile Coloration and Finishing
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• v.15 no.3
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• pp.176-184
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• 2003

This research aimed at scrutinizing the dyeability of some solvent dyes on polyester and their light fastness to be exploited as a breakthrough in light fastness where utmost fastness is required such as ultramicrofibers and industrial markets. Dyeability on polyester was mainly evaluated by HT exhaust dyeing according to the general procedure. Light fastness has been tested by a preliminary UV test followed by HT xenon test in compliance with standard SAE J1885, 224 KJ. Fading has been determined quantitatively by evaluating the shade deviation and the strength difference between unexposed and exposed samples by means of CIELab values.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04a
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• pp.337-340
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• 2001

A major impediment in using the Dempster-Shafer evidence combination scheme is its computational complexity, which in general is exponential since DS scheme allows any subsets over the frame of discernment as focal elements. To avoid this problem, we propose a method called approximate evidence combination scheme. This scheme is applied to a few sample applications and the experiment results are compared with those of VBS. The results show that the approximation scheme achieves a great amount of computational speedup and produces belief values within the range of deviation that the expert allows.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.56
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• pp.55-64
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• 2000

There is more than a single quality characteristic and they are often of varying or mixed target types. The purpose of this paper is to develop general strategies for solving the multiple response robust design problem. The desirability function provides an important tool to solve problems that have different types of target since the desirability values all the range between zero and one. Several combinations of arithmetic averages, geometric averages, and standard deviations are used in the various strategies to find the best design point.

• Bulletin of the Korean Chemical Society
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• v.10 no.2
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• pp.196-200
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• 1989

Some s-triazine herbicides, namely simazine, atrazine, and propazine present as trace components in a complex mixture were analyzed by GC/MS and GC/MS/MS methods. Even though monitoring the molecular ions was the best in terms of sensitivity, adequate analysis could not be done when interfering species were present. When doubly charged ions which appeared at characteristic m/z values were monitored, chromatograms were rather free from interference. More importantly, selected reaction monitoring was found to provide a selective means of detection with general applicability.

• Korean Journal of Occupational Health Nursing
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• v.10 no.1
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• pp.41-54
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• 2001

This study was designed to assess the relationship between occupational stress and health status in a study group of 197 workers employed in four newspaper publishing companies, using a self-adminstrative questionnaire. The types of occupation of them were reporters(79), clerical workers(54), and engineers (64). The studies on workers' health have been focused mainly on the physical, chemical, and biological diseases in our country. Therefore, the study of mental health, especially of occupational stress, is to be carried out. I consider stress as a factor having an effect on the health status of the newspaper employees, who have been well known to have high stress due to time pressures. I expect that this research will be helpful not only for understanding of health status by occupation, but also for making clear the issues that have been raised continuously from the previous researches. The results of this study are as follows; 1. The mean values of stress by occupation were statistically significant; the reporters had the highest stress symptom scores, and the engineers had the lowest levels of stress. The mean values of stress symptoms were higher in the workers who had long working hours. 2. The health status by occupation showed significant differences in gastrointestinal systems and in depression. The clerical workers were healthier than the engineers in gastrointestinal systems, and the reporters were more depressed than the engineers in depression. 3. The health status by the general characteristics, there was a statistical significance as for a gender, marital status, and absenteeism in the gastrointestinal systems. The men, the married, and the workers who had not been absent were more healthy. Only absenteeism had an effect on the problems in optical-dermal systems and in oro-fecal systems. Gender, marital status, absenteeism, and working hours were related with health status : the men. the married, the workers who had not been absent, and the workers who had longer working hours were more healthy. In mental stability, gender had a significant effect : the men were more healthy than the women. In general condition, the men, the older, the married, and the workers who had not been absent were more healthy. 4. Stress level had an effect on the health status in the respiratory systems, optical-dermal systems, oro-fecal system, depression, mental stability, general condition, and health condition. The workers who perceived more stress had more problems in their health status. 5. In the results of the multiple regression analyses, age in the respiratory systems, absenteeism in the optical-dermal systems, occupation and absenteeism in the gastrointestinal systems and in the oro-fecal systems, gender in depression and in mental stability, gender, age, absenteeism, and working hours in the general condition, absenteeism in the health condition had an effect on the health status of the workers.

• Journal of Preventive Medicine and Public Health
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• v.15 no.1
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• pp.95-110
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• 1982

For the purpose of investigation to identify the quantities of heavy metals contained in the tissues of the Korean people, a series of analyses was conducted with atomic absorption spectrophotometry to measure the amount of lead, cadmium and copper distributed in various tissues, such as brain, liver, kidney, heart, lung, spleen, large intestine, hair, muscle, fat, stomach, costal cartilage, blood and urine, obtained from 30 cadaverous bodies who were believed not exposed to the said heavy metals during their life time either occupationally or therapeutically. 1. Lead content: Inter-individual difference was noted in lead contents in each tissue, vis., the average content of lead in hair was the highest with $14.90{\pm}9.74ppm$. The next was in costal cartilage that contained $5.56{\pm}3.86ppm$. The average contents of lead in liver, kidney and muscle were the lowest in value, showing $1.11{\pm}0.92ppm,\;0.73{\pm}0.48ppm\;and\;0.06{\pm}0.06ppm$, respectively, The lead contents in tissues of children under the age of 10 were significantly lower than those of adults, and the higher values were shown in males than in females in general. The lead contents in most of the tissues such as hair, costal cartilage, kidney, lung, fat, stomach, large intestine, heart, muscle and urine were well correlated with age. 2. Cadmium content: The average content of cadmium in kidney appeared to be the highest of other tissues showing $20.72{\pm}9.82ppm$, and liver came next with the value of $1.17{\pm}0.99ppm$. It was estimated that 83.9% of the total cadmium absorbed into the body was stored in kidney, 4.796 in liver, and the remaining 11.4% was distributed in the rest of the tissues. Cadmium contents in tissues showed difference between both sexes showing higher values in the females than in the males, which was quite contrary to the lead content. Cadmium contents in tissues steadily increased in amount with age, showing a significant correlation with age in all tissues. 3. Copper content: The average content of copper in hair was the highest with $10.36{\pm}2.21ppm$, and liver came next with $6.31{\pm}1.24ppm$. The copper that was absorbed into the body was distributed in each tissue: 29.9% in hair, 18.2% in liver, $5{\sim}11.0%$ in brain, heart and kidney, and $3.0{\sim}3.5%$ in stomach, blood, and lung. The copper contents in tissues of children under the age of 10 showed significantly higher values in liver, kidney, heart and large intestine than those of the adults. The copper contents in brain, costal cartilage and fat were well correlated with age showing the highest correlation coefficient of 0.870 (p<0.01) in brain tissue. There was no difference in copper contents in tissues between both sexes, and the values were, in general, lower than those for Japanese.

• Journal of Biosystems Engineering
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• v.2 no.2
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• pp.37-45
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• 1977

Solar energy is a potential source of power that offers much promise being used for low-temperature applications like drying farm crops, space heating, and water heating for domestic uses. Already much of it are being used for those purpose in foreign countries. However, very little research has been done to determine the possibility of using the solar energy in Korea. This study was conducted to develop the general prediction equation of the total radiation on a horizontal surface in Daejeon area based on 5 years 91972, Jun.1-1976. Dec.31) meteorological data (bright sunshine hours, average total horizontal radiation), and to obtain experimentally the thermal efficiency of solar air and water collectors, which will be used as a basic data of designing flat-plate solar collector system.In addition to the thermal efficiency of the collectorsthe relationship among those factors affecting it such as weather condition, orientation factor, and tilted angle of collector was analyzed. The results of this study were as follows. 1. The general predicted equation of the total radiation on a horizontal surface in Daejeon area based on bright sunshine hours was developed as $H_{av} =(1.546\frac{n}{N}-0.582)H_o$. Predicting the total radiation on a horizontal surface by the above equation was thought to be possible because to values of 0.882 was smaller than any t values at above 0.05 level on the basis of two tailed test of the difference between the calculated and the recorded values. 2.It was observed that optimum tilt angle of the collector in the summer and the autumn drying season was 13 degrees and 51 degrees respectively, these values could be obtained by adding or substracting approximately 25 degrees from the latitude of this area $(36.3^{\circ}N)$ .The relationship between orientation factor and declination of sun at suitable tilt angle of 33 degrees $(s=0.9\O)$ was shown at Fig.4. 3.The thermal efficiency of solar wdter collector was shown 13.4-51. 6% on Aug. 15 (the minimum radiation recorded) and 43.8 ~537% Aug.20 (the maximum radiation recorded), and 13.8~ 46.6 and 44.3~ 49.7 were shown on each corresponding day. 4.The thermal efficiency of the collectors according to the weather condition was shown a big difference of about 10% between the day of the maximum radiation recorded and the minimum, but the differen of efficiency between the air and the water collector was at most 2 ~ 3%. 5. Even if the efficiency of the solar water collector was a little higher than the solar air collector, for drying farm products, the solar air collector was thought to be more effective because the air heated by collector could be directly used for drying them.

• Korean Journal of Veterinary Research
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• v.17 no.2
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• pp.63-71
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• 1977

During the period of March, 1976 to December, 1976, 48 raw milk samples were taken from dairy cows at 48 different dairy farms in Korea analyzed by gas liquid chromatography to determine the seasonal variation of the amount of organochlorine pesticide residues. At the same time 80 market milk, 10 beef and 10 pork samples were analyed by the same procedure for checking residual levels. The results were summarized as follows; 1. Milk samples from 17 dairy farms (36 per cent of tatal) were shown to be contaminated with various organochlorine pesticides. The residua lrate of ${\gamma}-BHC$ in tested samples were 44per cent (14 sam ples) that of aldrine was 28 per cent (9 samples) and those of pp'-DDT, dieldrin and heptachlor were 9.3 percent (3 samples) respectively. 2. In raw milk pp'-DDT, ${\gamma}-BHC$, aldrin, dieldrin and heptachlor were detected, and aldrin, dieldrin and heptachlor were detected in the market milk. Any kinds of organochlorine pesticides were not detected in beef samples but dieldrin and heptachlor were detected in pork samples. Average residual values of aldrin, dieldrin and heptachlor in the market milk were 0.0077 ppm (0.0000~1.1100 ppm), 0.0001ppm (0.0000~0.0500 ppm) and 0.0008 ppm (0.0000~2.0520 ppm), respectively, and those of dieldrin and heptachlor in pork samples were 0.0010 ppm (0.0000~0.0100 ppm) and 0.0033 ppm (0.0000~0.0330 ppm). respectively. 3. Residues of organochlorine pesticides in raw milk were extremely variable; in fact pp'-DDT was detected in milk samples from A, B, C and D districts and endrin was not detected from all districts. The ${\gamma}-BHC$ and dieldrin were detected at the district of A, C and D, aldrin at the districts of A and C and heptachlor at the districts of both A and D. 4. Seasonal trends of residual values of organochlorine pesticides were, in general, noticeable. The residual level was much higher in Spring than in other seasons and showed the tendeney of decrease from spring through summer and autumn generally; in the case of pp'-DDT average residual values were 0.0121 ppm in spring, 0.0022 ppm in summer and not detected in autumn. But in winter ${\gamma}-BHC$ and aldrin residues were increased a little. Residual values in raw milk (when cow are fed on hay and silage) were appeared higher in winter than the other seasons. 5. Residues of organochlorine pesticides in raw milk were not related in respect to hygienic conditions of dairy farms pp'-DDT and heptachlor were, in general, detected in all farms and aldrin was more detected in milk from well sanitated farms than poor sanitated ones.

• Journal of the Korean earth science society
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• v.37 no.1
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• pp.52-61
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• 2016

The purpose of the study was to create a probabilistic seismic hazard map using the input data that reflected the seismo-tectonic characteristics of the Korean Peninsula by applying USGS program (Harmsen (2008). The program was partly modified for the purpose of this study. The uncertainty of input parameters given by specialists was reflected in calculating the seismic hazard values by logic tree method. The general pattern of PGA was quite sensitive and similar to the shape of areal source. The probabilistic seismic hazard map showed the contour distribution of peak acceleration (%g) with 10% probability of exceedance in 5, 10, 20, 50, 100, 250, and 500 years. The result showed that the peak ground acceleration (PGA) values of the northern peninsula were almost half values of the southern peninsula except Hwanghae province. The general trend of the hazard map extended in the direction of NW-SE from Whanghae province to south-eastern regions of the peninsula. The values in northern part of Kangwon province were relatively lower than other areas in the southern peninsula. The maps produced through this study are considered valuable in regulating the seismic safety of the major facilities in the Korean Peninsula.