• Journal of Biosystems Engineering
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• v.20 no.4
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• pp.383-389
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• 1995

This study was conducted to develop an automatic nutrient control system for trickle application of nutrient solution. Temperature, electric conductivity(EC). pH and dissolved oxygen(DO) were selected as control variables. A controller using single-chip microcomputer was constructed. An automatic control system for nutrient solution and a controller using single-chip microcomputer with control algorithm were developed. The control system was tested, and could control temperature, EC and pH within the error ranges of $pm 0.2^{circ} pm 0.2mS/cm, pm 0.1pH$, respectively.

• The Korean Journal of Ecology
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• v.21 no.4
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• pp.329-335
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• 1998

The growth of Phytolacca L. grown under three light regimes at three nutrient concentrations was analyzed. The effect of shading treatment on plnat growth was greater than that of nutrient treatment. Plant dry mass increased more than 5-fold during 21 days under 33% and 100% irradiances, whereas that was strongly reduced under 8% irradiance. Net assimilation rate decreased with plant growth irrespective of light and nutrient treatments, though the highest net assimilation rate was shown under 100% irradiance. Under 33% irradiance leaf area in plants supplied with nutrient solution increased to such extent as to compensate reduction in net assimilation rate, whic maintains almost identical growth rate with that under 100% irradiance. The relatonship between total plant nitrogen and leaf nitrogen content was dependent on the growth irradiance. Moreover, leaf nitrogen and specific leaf weight were also changed depending on the light and nutrient conditions. Based on these findings, it is suggested that the adaptive characteristics of Pokeberry plant to light and nutrient conditions may contribute to rapid extension of Pokeberry habital in Korea rocently.

• Journal of Bio-Environment Control
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• v.1 no.2
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• pp.162-168
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• 1992

As the automation of nutrient solution management proceeds in the field of hydroponics, effective supporting systems to manage the nutrient solution by computer become needed. This study was attempt to predict the EC of nutrient solution using the neural networks. The multilayer perceptron consisting of 3 layers with the back propagation learning algorithm was selected for EC prediction, of which nine variables in the input layer were the concentrations of each ion and one variable in the output layer the EC of nutrient solution. The meq unit in ion concentration was selected fir input variable in the input layer. After the 10,000 learning sweeps with 108 sample data, the comparison of predicted and measured ECs for 72 test data showed good agreements with the correlation coefficient of 0.998. In addition, the predicted ECs by neural network showed relatively equal or closer to the measured ones than those by current complicated models.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.595-602
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• 2023

Feed processing methods can substantially enhance the nutrient value of feed. The aim of our study was to compare the effects of mash or crumble feed on growth performance, nutrient digestibility, back-fat thickness, and carcass quality of growing-finishing pigs. In total, 50 ([Landrace × Yorkshire] × Duroc) growing pigs with initial body weight of 46.24 ± 3.57 kg were randomly assigned to two dietary treatment groups. The two dietary treatments were: 1) mash and 2) crumble feed forms for 14 weeks of trials. Five replication pens per treatment, comprised five pigs (2 males and 3 females) each. Growth performance, nutrient digestibility, back-fat thickness, and carcass quality were observed at different weeks. There were no significant differences in growth performance, nutrient digestibility, back-fat thickness, and carcass quality throughout the experimental trial. Further study is required to understand the effects of mash and crumble feed on growing-finishing pigs.

• Nutritional Sciences
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• v.8 no.1
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• pp.56-60
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• 2005

The aim of this study researchs status of the nutrient intake between male and female students and the nutrient intake by BMI. This study was done to investigate the body composition and nutrient intakes of 340 college students (170 males, 170 females) in Gyeonggi area. Weight, height, BMI, and blood pressure of these college students were measured Nutrient intake was assessed using the 24-hour recall method, and then calculated using the nutritional evaluation program [CAN Pro 2.0 professional (Korean Nutrition Society, 2002)]. Average height and weight were 176$\pm$5.1 cm, 70.60$\pm$l.l kg in male students and 162.2/$\pm$4.5 cm, 54.4$\pm$7.7 kg in female students respectively. Subjects were divided into three groups by BMI: underweight (less than 18.5), normal weight (18.5 to less than 23), and overweight (more than 23). The ratios of male and female subjects among these groups were 5.3% and 17.6% in underweight, 50% and 65.3% in normal weight, and 44.7% and 17.2% in overweight. Systolic and diastolic blood pressures were 124.0$\pm$1.5 mmHg and 76.1$\pm$14.8 mmHg in males and 1l0.l$\pm$12.9 mmHg and 70.l$\pm$10.8 mmHg in females, all in the normal range. Using nutrient values of the 7th Recommended Dietary Allowanes, the nutrient intake was calculated to Korean RDA (%). Nutrients below 75% Korean RDA were Calcium, Vitamin $B_2$, and Folate and nutrients above 100% RDA were Protein, Fe, Phosphorous, and Vitamin $B_6$. BMI showed positive correlations with body fat (%)(p<0.01) and WHR (p<0.01). Nutritional education is desirable for the improvement of dietary behaviors, body composition and nutrient intake of college students.

• Journal of the Korean Dietetic Association
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• v.11 no.1
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• pp.114-124
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• 2005

The nutritional status of pre-school children is important for both physical growth and functional development. This study investigated the anthropometric, nutrient intakes and dietary quality of the pre-school children living in Asan for planning nutritional education program. The dietary intakes were measured by 2-day 24 hr recall recorded by children's mothers and the anthropometric data were collected by measuring children's weights, heights, and percent body fat at Asan Public Health Center. The children were 161 boys and 129 girls aged 5 and 6 years. When children's nutritional status was determined by their anthropometric status (underweight, normal weight and overweight) determined by z-score (normal range between -1.00 and 1.00), only 1.4% of the children belonged to underweight group while 55.7% and 42.9% belonged to normal and overweight groups, respectively. Significantly higher number of children belonged to overweight group for 5 year-olds. No differences were observed in nutrient intakes, nutrient adequacy ratio (NAR) and index of nutritional quality (INQ) values among nutritional status groups. Intakes of the most nutrients were adequate, but NAR and INQ of calcium and zinc were low. When nutrient intakes, NAR and INQ were compared by sex or age, all nutrient intakes were appropriate except calcium and zinc intakes of 6 year-olds. Nutrient intakes of 5 years were higher than those of 6 years. The mean of nutrient adequacy ratio (MAR) was 0.85 and mean INQ was 1.51 for all participants. The nutritional management program for pre-school children in Asan would be directed differently by age groups and education material should contain contents educating to consume moderate amount of food for 5 year-olds and to increase intake of foods with mineral nutrients such as calcium and zinc for 6 year-olds.

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.277-283
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• 1997

The effect of nutrient concentration and plant growth regulators on rooting of Coleus stem cuttings were investigated. In contrast to sand cutting, the nutrient solution or plant growth regulator treatment increased the root numbers and root length. The concentration of nutrient solution were 1, l/2 and 1/4 strength of the balanced nutrient solution developed by Japanese Horticultural Experimental Station and the highest root growth was obtained from 1/4 strength nutrient concentration. NAA or IBA treatment in culture solution stimulated the rooting and 0.01mg/l of NAA or IBA was effective in root development. Furthermore, days for rooting were shortened and root growth were promoted by mixing nutrient solutions with plant growth regulators and by using cutting with leaves. The rooting of Coleus was observed under microscope and the adventitious root formation initiated at 3 days after cutting with nutrient and auxin mixture.

• Korean Journal of Human Ecology
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• v.16 no.6
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• pp.1231-1241
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• 2007

This study was conducted to investigate the nutrient supplement use and its related influencing factors by high school students in Chonbuk area. Self administered questionnaires were collected from 489 (urban: 268, rural: 221). Statistical data analysis was completed using a SPSS v. 10.0 program. The results are summarized as follows. According to the general characteristic of subjects, the job and education level of parents and family monthly income respectively affected the nutrient supplement use of subjects (p<0.001). According to the living area, taking a nutrient supplement of parents and nutritional information respectively affected the nutrient supplement use of subjects (p<0.001). About 42.2% of subjects, who taking a nutrient supplement, responded to take a traditional medicine type, and 24.4% of them a multivitamin. Their mothers were important recommended person. The main reason for taking was 'to recommended from parent' (38.5%) and 'recovery from tiredness' (29.6%). The main reason for not-taking was that they were health, therefore nutrient supplements were not necessary. In the future about 43.7% of urban and 33.9% of rural area responded to take a nutrient supplements (p<0.05). These findings show that the behaviors of nutritional supplement usage by subjects are not reasonable, and their supplement usage tends to be affected by general characteristics. Therefore, nutritional understanding and education that are intended to from reasonable behaviors toward nutritional supplement usage of adolescents should be provided with considering the relationship between general characteristic of subjects and supplement usage.

• Journal of Nutrition and Health
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• v.33 no.4
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• pp.429-437
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• 2000

Contributions of specific foods to absolute intake and between-person variance in 13 nutrients were examined to develop a short food frequency questionnaire (FFQ) for the Korean elderly using dietary data collected by a semiquantitative FFQ with 96 food items. The contributions of specific foods to 90% absolute nutrient intake were measured by assessing their percentage to the total consumption of a nutrient by our samples(n=98). To assess the contribution of the foods to the between-person variance in intake of each specific nutrient, stepwise multiple regression was performed. Cumulative R2 served as the measure of contribution to variation in intake. The most important food source of absolute intake was rice for energy and protein. Important foods of between person variance contribution include bread for energy and pork for protein. Important foods of absolute and variance contribution of nutrient intake were similar for fat(noodles including jajangmyun and kalguksu), calcium(anchovy and milk) and vitamin A (carrot). The number of foods necessary to account for the variation in nutrient intake among older people in Korea differ considerably by nutrient: 18 - 43 and 8-26 foods were accounted for the respective 90 and 80% of absolute intake depending on nutrients. Carbohydrates and vitamin A and C had relatively a few major sources, thus may be assessed well by a small number of foods. Conversely, iron, potassium and B vitamins appear to need longer lists of foods. Fewer numbeer (6 - 12 and 4 - 9) of foods were required for the corresponding percentages of between-person variation for all nutrients. Depending on nutrients, 0.980-0.995 and 0.924-0.987 were respective correlation coefficients of nutrient intakes measured by 96 food items with those by lists of foods for 90% and 80% of absolute intake contribution. These findings suggest that an incomplete food list on the basis of its contribution to absolute and between person variation intakes may still be effective in discriminating among individuals. The results of this study may be useful in the design and use of dietary questionnaire.

• Nutritional Sciences
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• v.6 no.2
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• pp.113-117
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• 2003

Possible correlations between nutrient intake add health status-as assessed by anthropometric measurements, physical performance and biochemical measurements-were investigated, using 514 healthy young men aged 20 years old who had no apparent health problems. The intakes of nutrients were estimated using a three-day dietary recall method. Height and body weight were measured, and body mass index (BMI) was calculated. Physical performance was tested using sit-ups, push-ups, a loom sprint and a 1,500m run. When compared with the Korean recommended dietary allowances (Korean RDA), the subjects nutrient intakes were adequate except for calcium. The intake of calcium was 516.66$\pm$293.43mg/day, which is 73.80 % of the Korean RDA. The subjects averaged 174.51$\pm$7.07cm in height, 68.17$\pm$9.25 kg in body weight and 22.23$\pm$2.16 in BMI. The associations between nutrient intakes and anthropometric measurements, and between nutrient intakes and physical performance, were weak. The intake of vegetable fat was positively correlated to body weight, whereas the intake of carbohydrate was negatively correlated to BMI. The intake of carbohydrate was positively correlated to the level of performance in the loom sprint, and the intake of vegetable Int was positively correlated to the level of performance of sit-ups. No correlation was found between nutrient intakes and the following biochemical measurements of the blood: the levels of glucose, total protein, total cholesterol, triglyceride, hemoglobin and hematocrit. These results suggest that anthropometric measurements and level of physical performance can be associated with energy nutrient intakes, even in moderately active, well-nourished, young men. No correlation was found between nutrient intake and biochemical measurements, probably because all subjects had a reasonably well-balanced diet.