• Journal of the Korean Society of Marine Environment & Safety
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• v.2 no.1
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• pp.89-95
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• 1996

This paper describes a fuzzy controlled pre-chlorination technique for purifying the pulluted raw water in water purification lants. For the purpose of obtaining the high quality water, the appropriate pre-chlorine dosage rate has to be continuously adjusted according to a change in quality of a intake raw water, weather, solar nergy mount, temperature and etc. Therefore, the method of expressing an expert's empirical knowledge cumulated from his past carrier by fuzzy reasoning and the fuzzy controller design technique is necessary.In this paper fuzzy membership functions and rules accordingto emprircal knowledge and experimental field data were obtained, And also fuzzy cintriller design using four feedforward components for the determination of pre-chlorine dosage rate and four feedback ones for the compensation of its dosage rate with residual chlorine and its change rate, was executed.

• IE interfaces
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• v.16 no.1
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• pp.27-33
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• 2003

The maintenance cost in K Steelworks has been continuously increased in proportion to the production cost. However, there seems to be a possibility of reducing cost through the optimization of maintenance actions. The failure types of the equipment in steelworks ate various with different failure cost. Thus the failure rate and cost of each type of failures should be considered simultaneously when the optimum maintenance period is to be determined. It is considered that the equipment undergoes periodic replacement and a specified number of incomplete preventive maintenance actions are performed during a replacement period. Assuming that the time to failure follows a Weibull distribution, the parameters of the failure rate are estimated using the maximum likelihood estimation. The optimal replacement period is determined to minimize the average cost per unit time. As the result of analysis it is suggested that the existing maintenance period for a hot-rolling equipment can be extended significantly.

• Journal of the Korean Graphic Arts Communication Society
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• v.11 no.1
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• pp.17-29
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• 1993

As inverstigating the influence of monomers and photoinitiator in the polymerization rate of photopolymerization by using IR spectroscopy, photopolymerizations initiated by ultraviolet radiation are characterized by the presence of an autoacceleration in the polymerization rate as the reaction proceeds. The conversion for the end of the autoacceleration varies considerably depending on the monomer and reaction condition which determines coil size and viscosity. In UV curable systems, the autoacceleration begins at only a few percent conversion and continues to 40% in HEA solution and 60% conversion in EHA solution. The polymerization ate in HEA solution increased as follow; DMHA > HCPK > DMPA and could be explained by the interaction between the initiating radical and HEA monomer and the size of the photodissociated radical of initiator. But the tendency of autoacceleration in EHA solution is almost independent on initiator.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.284-286
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• 1994

This paper describes the dielectric characteristics of $SF_6$ gas in non-uniform electric filed under lightning under lightning impulse and oscillating impulse voltages. The breakdown voltage-time characteristics and the breakdown voltage-pressure characteristics are measured over a pressure range extending from 0.1 to 0.5 [MPa] fur the coaxial electrode with a needle protrusion. The curvature radius of needle protrusion is 0.3[mm]. Also, the growth of the predischarge is simultaneously observed. As a result the polarity effect is pronounced, and the breakdowns voltage under the oscillating impulse voltage are higher than those under the lightning impulse voltage. It is found that the breakdown mechanism md predischarge phenomena ate closely related with the polarity and waveforms of the testing voltage.

• Korean Journal of Community Nutrition
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• v.6 no.1
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• pp.16-27
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• 2001

The purpose of this study is to determine the prevalence of obesity and to examine the eating habits of elementary school students in Iksan dity. The study was carried out on 292 students(male: 151, female : 141)in May of 1997. The average height and weight of the subjects were 141 cm and 37kg in males and 142 cm and 36kg in females, which were similar to the average of Chonbuk. A Weight/Length Index(WLI), Broca Index, Rohrer Index(RI), Body Mass Index(BMI) and Waist Hip Ratio(WHR) were used as an obesity index to classify degree of obesity. WLI, Broca Index and RI were proper for judging child obesity and strict judgments were conducted in the order of RI, WLI and Brcoa Index. The subjects were classified as 30.8% underweight, 43.5% normal, 8.2% overweight and 17.5% obese by WLI and there were significant differences between height(p＜0.05) and weight(p＜0.01) according to obesity degree among the four groups. 50.3% of the boys and 55.3% of the girls are regularly, and the main reason they didn＇t ate regularly, and the maim reason they didn＇t eat breakfast(78.4%) was due to lack of time. The frequency of snacks were 1-2 times a week(40.4%), fruits(40.4%) from market and supermarket(68.2%). According to the survey 84.6%, 77.45, 78.1%, 69.9%, 59.9% and 86.6% of subjects didn＇t eat meat, fish, soysauce, instant food, sugar and seaweed respectively. Seaweed, meat, and soysauce showed low preferences. 69.5% and 74.75 of the subjects drink milk and ate kimchi respectively. By analyzing eating habits according to the degree of obesity, the rate of skipping breakfast(p＜0.01), and eating meat or fish(p＜0.05) were high in the overweight and obese groups of girls. In the boys case, the rate of not eating food in sugar(p＜0.05) was high in the obese group. Obese children need to correct their eating habit. This reasserts the importance of nutrition education in children though teachers, parents, and dietitions. The findings of this study may be applied to nutrition education to ensure better physical fitness for children.

• Journal of Korean Home Economics Education Association
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• v.34 no.2
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• pp.21-40
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• 2022

This study was conducted to survey students' current eating behavior and nutritional knowledge to provide researchers with basic data that can help students with positive, practical, and healthy eating habits. For this purpose, a self-administered questionnaire was distributed to students of a vocational high school located in Gyeongsangnam-do. A total of 270 questionnaires were collected from a convenience sample and the data were analyzed using SPSS Version 25.0. The results are as follows. First, 57.40% of students lived with "parents," and 55.56% of students' household monthly income levels were "Low." Second, as for the eating behavior of the subjects, the students who ate 'two meals' a day showed the highest at 64.81%, 'one meal' occupied 17.41%, and those who ate one meal a day, 'School cafeteria' was the eating place most frequently mentioned (65.96%). Third, when students were classified based on their nutritional knowledge levels, "High" group comprised 37.78%, "Moderate" group 37.41%, and "Low" group 24.81% of the total students. Regarding the experience of nutrition education, 64.44% answered 'no experience of nutrition education' in the last 12 months, and among the 35.56% of students who had received nutrition education, 72.92% received the education from school teachers. Based on these results, to prevent problems with the eating habits that can occur to vocational high school students, organic cooperation between families, schools, and local communities is required. Furthermore, full support from the government is needed. In addition, more efforts are needed for practice-oriented dietary education so that nutritional knowledge can be converted into correct eating behavior.

• Journal of the Korean Society of Food Culture
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• v.24 no.2
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• pp.224-235
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• 2009

This study aimed to research meal quality and the dietary behaviors of college students for desirable dietary lives and provides basic data for nutritional education by examining polymorphism distribution of the UCP2 gene according to gender, by investigating attitudes in terms of their dietary habits and dietary lives, and by analyzing serum lipid levels and body composition. A survey was conducted with a total of 222 students - 93 male and 129 females. Based on a selfreporting method, the questionnaires were answered over 20 minutes, and UCP2 insertion/deletion gene polymorphism and blood samples were also analyzed. The results showed that the male students and female students had average BMI of 22.50 and $20.73\;kg/m^2$, respectively. According to answers regarding their dietary lives, 51.4% of the students showed 'irregular eating' patterns, which is regarded as something to be corrected. In terms of eating regularity, 51.6% of the male students and 59.7% of the female students had irregular meal schedules. As the most important meal of a day, 64.0% of the students answered 'breakfast' but only 53.6% answered that they ate breakfast everyday. In addition, 39.8% of the male students and 50.4% of the female students ate between meals 'once a day'. When questioned if they were satisfied with their body shape, 17.8 and 45.2% of the male students answered they were 'satisfied' or needed to 'gain weight', respectively, whereas 17.8 and 77.5% of the female students answered they were 'satisfied' or needed to 'lose weight', respectively. The results of the UCP2 gene polymorphism analysis showed that 33.7% of the males belonged to the DI heterozygote group, 64.2% belonged to the DD homozygote group, and 2.1% belonged to the II homozygote group. For the female students, 63.4% belonged to the DI heterozygote group, 35.1% belonged to the DD homozygote group, and 1.5% belonged to the II homozygote group. According to the blood and serum lipid analyses, the male students showed average HDL-cholesterol, LDL-cholesterol, and hemoglobin levels of 57.20, 93.80, and 15.00 mg/dL, respectively, while the female students presented average levels of 56.69, 102.88, and 13.13 mg/dL, respectively. In conclusion, this study found no significant effects in terms of UCP2 gene polymorphisms, but it is suggested that practical plans must be designed that allow college students to use nutritional knowledge in their daily lives, and in particular, nutrition education needs to be develop that would enable female college students to recognize their bodies appropriately and to control their weight in desirable ways.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.4
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• pp.3991-4000
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• 1975

It is the aim of this study to investigate the influence of the factors in the sprayer nozzle for the travelling distance and to get nozzle design data in relation to the nozz1e with and without swirl plate. The factors of sprayer nozzle are composed of the spraying pressure, the helical angle of swirl plate, the helical groove depth of swirl plate, the distance of vortex chamber the slope of nozz1e cap, the curvature of nozzle cap and the hole diameter of nozz1e cap. The travelling distance and the size of sprayed particle are experimeted indoors by the factorial arrange-ment according to the 5 each level of the above factors. The results of this stupy are summarized as follows; 1. In the nozzle with swirl p1ate there were remarkable significance among factors each other, while without swirl plate were no significance. 2. The helical angle and groove depth in the nozzle with swirl plate were the highest effective factors. The effect of helical angle was very remarked in the quadratic curve with minium value. 3. The correlation betweenthe travelling distance and the sprayed particle size was no high and under 250 micron in the case with swirl plate, and there was higher correlation in the case without swirl plate. 4. The new ideal development of the swirl plate using of the most effective helical angle and groove depth will probably show the possiblities to make effective travelling distance over 8 meters and more over and to make average particle diameter under 300 micron.

• Journal of Technologic Dentistry
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• v.11 no.1
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• pp.5-22
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• 1989

We investigated 974 male and female students who are in 4th, 5th and 6th year of 8 elementary schools are located win Puan-kun, the farm area of Chollabuk-do, and the results are as follows. 1. Visiting dental clinic in order to be treated for dental caries hold the highest rate as 26.1% of male students and 30.3% of female students. 2. On fear when children visit dental clinic, first, 25.6% of male students and 35.1% of female students mark the highest rate as some what fear. Second, 23.1% of male students represent to be usual and 29.4% of female students represent to be very fear. There fore it speaks for dissimilarity in character between male and female students. 3. On reason of developing dental caries, 62.5% of male students and 55.8% of female students replied that it was developed because they frequently ate the sweet things. 4. Children who pull out decidous teeth alone mark the highest rate as 44.7% of male students and 38.6% of female students. 5. On important thing for ordinary dental health, 56.2% of male students and 58.5% of female students as the highest rate replied that they often brushed their teeth.

• Journal of The Korean Society of Grassland and Forage Science
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• v.1 no.1
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• pp.10-17
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• 1978

The experiment were carried out to determine the rate of regrowth, the changes of carbohydrates contained in the samples right after cutting, plant part for storage of carbohydtates and top-dressing time of ladino clover and orchardgrass. Plants were grown in the simple growth chamber as well as in the fields. The temperature, light intensity and light period were controlled to be 15-20$^{\circ}$, 4,250 Lux, and 15 hours in the simple growth chamber. The results obtained are as follows ; 1. The period of recovery to initial stands after cutting was about 3 weeks in ladino clover and 4-5 weeks in orchard grass in terms of dry matter and carbohydrates. 2. The content of total water-soluble carbohydrates of plant parts was the hightest in stolon of ladino clover and in sheath of orchardgrass, and the lowest in roots of ladino clover and orchardgrass. 3. Cutting resulted in a temporary decrease of total water-soluble carbohydrates in the shoots. Similar trends were observed when the plants were left intact with top-dressing. 4. The top-dressing applied simultalliousely with the cutting was more effective to stimu1ate regrowth than that applied after cutting, however, both of the simultaneous and after cutting application were still better than application prior to cutting.