• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1659-1663
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• 1991

A new control design methodology is presented here which is based on a nonlinear time-series reference model. It is indicated by highly nonlinear simulations that such designs successfully stabilize troublesome aircraft maneuvers undergoing large changes in angle of attack as well as large electric power transients due to line faults. In both applications, the nonlinear controller was significantly better than the corresponding linear adaptive controller. For the electric power network, a flexible a.c. transmission system (FACTS) with series capacitor power feedback control is studied. A bilinear auto-regressive moving average (BARMA) reference model is identified from system data and the feedback control manipulated according to a desired reference state. The control is optimized according to a predictive one-step quadratic performance index (J). A similar algorithm is derived for control of rapid changes in aircraft angle of attack over a normally unstable flight regime. In the latter case, however, a generalization of a bilinear time-series model reference includes quadratic and cubic terms in angle of attack. These applications are typical of the numerous plants for which nonlinear adaptive control has the potential to provide significant performance improvements. For aircraft control, significant maneuverability gains can provide safer transportation under large windshear disturbances as well as tactical advantages. For FACTS, there is the potential for significant increase in admissible electric power transmission over available transmission lines along with energy conservation. Electric power systems are inherently nonlinear for significant transient variations from synchronism such as may result for large fault disturbances. In such cases, traditional linear controllers may not stabilize the swing (in rotor angle) without inefficient energy wasting strategies to shed loads, etc. Fortunately, the advent of power electronics (e.g., high-speed thyristors) admits the possibility of adaptive control by means of FACTS. Line admittance manipulation seems to be an effective means to achieve stabilization and high efficiency for such FACTS. This results in parametric (or multiplicative) control of a highly nonlinear plant.

• Journal of Korea Water Resources Association
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• v.33 no.6
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• pp.733-744
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• 2000

Due to the randomness of reservoir inflow and supply demand it is not easy to establish an optimal reservoir operation rule. However, the operation rule can be derived by the implicit stochastic optimization approach using synthetic inflow data with some demand satisfied. In this study the optimal reservoir operation which was reasonably formulated as Linear Tracking model for maximizing the hydro-energy of seven reservoirs system in the Han river was performed by use of the optimal control theory. Here the operation model made to satisfy the 2001st year demand in the capital area inputted the synthetic inflow data generated by multi-site Markov model. Based on the regressions and statistic analyses of the optimal operation results, monthly reservoir operation rules were developed with the seasonal probabilities of the reservoir stages. The comparatively larger dams which would have more controllability such as Hwacheon, Soyanggang, and Chungju had better regressions between the storages and outflows. The effectiveness of the rules was verified by the simulation during actually operating period.period.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.5
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• pp.663-675
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• 1995

It has been proposed that differences in diet between smokers and nonsmokers may partially explain the positive association between cigarette smoking and chronic diseases such as cancer and coronary heart disease. To investigate the potential for this confounding, the authors studied the relation between cigarette smoking and dietary pattern including nutrient intake in 152 Korean elderly people aged 59∼84years. Dietary intake was determined by a 24-hour recall method and a food frequency questionnaire. Male smokers were lighter than nonsmokers and had a lower body mass index(BMI)(p<0.05). But there were no differences in body weight and BMI between female smokers and nonsmokers. Female smokers had lower intakes of energy and carbohydrates than nonsmokers(p<0.05), but in male, smokers and nonsmokers did not show the difference in energy intake. The mean intake of fiber, protein, fat, minerals, and vitamins did not vary significantly by smoking status. However, both male and female smokers consumed fewer fruits than nonsmokers and ate fresh fruits less often than nonsmokers. The total food frequency score which reflect dietary quality of smokers was lower than those of nonsmokers(p<0.05). Male exsmokers' diet were similar to those of smokers, but in female, dietary patterns of exsmokers were similar to those of nonsmokers. These results confirm that elderly smokers have partially different nutrient and food intake patterns from nonsmokers. The decreased ingestion of fruits and less balanced diet by cigarette smokers could contribute to their increased risks of chronic disease compared with those by nonsmokers. The increased ingestion of nutrients and improved nutritional balance in the diet of exsmokers may help to reduce their risks as well.

• The Korean Journal of Food And Nutrition
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• v.22 no.4
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• pp.577-586
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• 2009

Aging is associated with decreased energy expenditure, thermogenesis and energy requirements. Maintenance of physical fitness of the elderly has been reported to reduce the rate at which the basal metabolic rate, muscle strength, skeletal muscle mass and bone density deteriorate. Skeletal muscle disease is known to increase the risk of physical disability and psychological problems. This study was conducted to investigate changes in disability, emotional problems, body compositions, obesity indices and nutrient intake levels according to physical fitness with the elderly in rural areas. According to the results, physical fitness was negatively related with Activities of Daily Living(ADL, p<0.05), Instrumental Activities of Daily Living(IADL, p<0.001), Body Mass Index(BMI, p<0.001) and abdominal obesity(p<0.05), while it showed a positive correlation with the General Self Efficacy Scale(GSES)(p<0.001) and nutrient intake(p<0.05). When changes in these factors were compared according to the range of quartile of the Fullerton Advanced Balance Scale(FAB Scale), GSES(Q1=35.3, Q2=43.5, Q3=53.2, Q4=51.9, p<0.001), BMI(Q1=36.1%, Q2=34.7%, Q3=33.2%, Q4=28.6%, p<0.01), abdominal obesity(Q1=1.02, Q2=0.99, Q3=0.97, Q4=0.94, p<0.001) and nutrient intake(Q1=71.1%, Q2=75.4%, Q3=80.6%, Q4=80.2%, p<0.05) differed significantly. Taken together, these results suggested that better physical fitness would lead to a reduction in negative factors including physical disability and obesity indices, but to an increase in positive factors such as GSES and nutrient intake. The results of this study are expected to be used as basic data for the development of programs to promote the health of the elderly in a local society.

• Journal of Nutrition and Health
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• v.28 no.8
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• pp.759-770
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• 1995

This study was conducted to investigate the effect of weight control by use of commercial formula diet and nutrition education on 36 obese women over a period of 6 months. During the study it motivated ways for women to control their weight and improve their health, thus analyzing variables that influence weight control. To help weight control, for the first 3 weeks, along with 1 regular mea, 2-3 liquid formula diets of 135㎉ per pack a day were provided within the 1,200-800㎉ range. For 6 months since then, all 3 meals were taken regularly and it was recommended that energy which is 500㎉ less than energy requirement be taken. To evaluate the effect of weight change by the weight control program, anthropometric measurements, biochemicl parameter, and food behavior are measured. The mean body mass index(BMI) was 30.1$\pm$3.8(25.0-43.6) and it was in the upper 5 percentile of the mean BMI of Korean women. The percent of body fat was significantly reduced from 29.1$\pm$2.4 to 26.4$\pm$2.3, showing that the weight control program induced not only a change in weight but also a change in body composition. The body circumference such as waist and hip circumference and skinfold thickness measurements of biceps, triceps, subscapular and surprailiac were reduced significantly, but the mean waist-to-hip ratio didn't change. Singnificantly improved food behavior score measured by the questionnaire indicated that the weight-contorl program induced the change of the food behavior, as well. Weight loss also induced biochemical parameters of the subject, thus total cholesterol, LDL-Cholesterol, and triglycerol which were in the high range of the normal values were reduced to 20.2%(p<0.01), 22.2%(p<0.01), 25.8%(p<0.01), repectively. HDL-cholesterol didn't change significantly, but the ratio of HDL to total cholesterol increased(p<0.01).

• Nutrition Research and Practice
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• v.14 no.2
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• pp.134-142
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• 2020

BACKGROUND/OBJECTIVES: North Korean refugees (NKRs) in South Korea are a unique population as they must adapt in a new country with similar cultural traits but different social, political, and economic systems, but little research has been conducted on diet and nutrition in this population. This study examined food security, dietary behaviors, and nutrient intakes among adult NKRs living in South Korea and compared them to those of South Koreans. SUBJECTS/METHODS: The subjects were 139 adult NKRs (25 men, 114 women) living in the Seoul metropolitan area, and 417 age- and sex- matched South Korean controls (SKCs; 75 men, 342 women) selected from the Korea National Health and Nutrition Examination Survey (KNHANES). Food security and dietary behaviors (meal skipping, eating-out, meals with family, nutrition education and counseling, and nutrition label knowledge and utilization) were obtained using self-administered questionnaires. Nutrient intakes were assessed by 24-hr recall. The statistical analysis was performed using IBM SPSS ver. 23.0. RESULTS: In South Korea, food security had improved over the previous 12 months, but remained significantly poorer for NKR women than SKC women. Meal skipping was three times more frequent than for SKCs and eating-out was rare. Average energy intake was 1,509 kcal for NKR men and 1,344 kcal for NKR women, which was lower than those of SKCs (2,412 kcal and 1,789 kcal, respectively). Significantly more NKRs (men 24.0%, women 21.9%) showed simultaneously deficient intake in energy, calcium, iron, vitamin A, and riboflavin than SKCs (men 2.7% (P = 0.003), women 7.0% (P < 0.001)). NKR women had a significantly higher index of nutrient quality (INQ) for some nutrients than SK women. CONCLUSIONS: This study reports significant differences in food security, dietary behaviors, and nutrient intakes between NKRs and SKCs. Generally, NKRs reported lower intakes despite improved food security, but relatively good INQs across nutrients. Further research is needed to understand processes of food choice and consumption among NKRs to provide appropriate support aimed at improving diets.

• The Korean Journal of Community Living Science
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• v.20 no.1
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• pp.19-32
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• 2009

The purpose of this study was to examine household food insecurity and the associations of food insecurity with socioeconomic characteristics, food behaviors, health status and nutrient intake among elderly people in a rural area. This study included 191 elderly people (mean age = $72.0{\pm}7.4$) in Jeollabuk-do, Jangsu-gun. House food insecurity was measured using an adapted version of the USDA short form household food insecurity scale, and nutrient intake measured by a 24-hour dietary recall. Only 15.2% of the subjects were in food-insecure households, 84.8% of the elderly households were food-secure. The food-insecure households were significantly lower in the number of family, frequency of shopping, and perceived health status than the food-secure households. In addition, they had serious tooth problems and NSI (Nutrition Screening Index) scores. Food-insecure households were significantly lower in most areas of nutrient intake (energy, protein, fat, Ca, P, Fe, K, Na, Zn, Vit. $B_2$, niacin, Vit. E), and also lower in nutrient intake compared to dietary reference intake (energy, protein, P, Fe, K, Na, Vit. $B_1$, Vit. $B_2$, niacin, Vit. E). These results suggest that the household food insecurity measures used in this study were an important indicator of nutritional well-being among elderly persons in the rural area. Food insecurity should be considered an important issue to public health and food service programs should be expanded for food-insecure households in rural areas.

• Journal of Powder Materials
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• v.26 no.6
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• pp.487-492
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• 2019

Titanium dioxide (TiO₂) is a typical inorganic material that has an excellent photocatalytic property and a high refractive index. It is used in water/air purifiers, solar cells, white pigments, refractory materials, semiconductors, etc.; its demand is continuously increasing. In this study, anatase and rutile phase titanium dioxide is prepared using hydroxyl and carboxyl; the titanium complex and its mechanism are investigated. As a result of analyzing the phase transition characteristics by a heat treatment temperature using a titanium complex having a hydroxyl group and a carboxyl group, it is confirmed that the material properties were different from each other and that the anatase and rutile phase contents can be controlled. The titanium complexes prepared in this study show different characteristics from the titania-formation temperatures of the known anatase and rutile phases. It is inferred that this is due to the change of electrostatic adsorption behavior due to the complexing function of the oxygen sharing point, which crystals of the TiO₆ structure share.

• Journal of Nutrition and Health
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• v.26 no.2
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• pp.164-173
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• 1993

This study was aimed to investigate whether abdominal obesity is associated with non-insulin dependednt diabetes. The distribution of body fat patterns was observed in 181 female patients with diabetes, aged 33 to 83 years, living in the Taegu area, Korea. The following anthropometric measuremetns were made on all participants from October 1 to November 25, 1991 : weight, height ; waist and hip circumferences in standing position. The waist hip circumference ratio was used as an index of abdominal obesity. The results were as follows; 1) The mean fasting blood glucose of diabetic subjects was 145$\pm$50.3mg/dl and the mean duration of diabetes was 4.7$\pm$7.5 years. 2) Obese subjects above the ideal body weight body weight of 120% in the investigation are presently 52%, but 63% of subjects were reported to be obese in the past. The mean BMI of the subjects is 24.57$\pm$3.15 and the past mean BMI was 27.13$\pm$3.26. One year after reaching their highest body weight, 47% of the subjects developed diabetes. Two years after reaching their peak body weight, 74% of diabetic subjects developed diabetes. 3) Using the waist-hip circumference ratio, subjects beloing to the upper body obesity(WHR>0.84) were 65.5%. 4) The average daily energy intake did not differ between the obese and non-obese diabetic subjects, whether they were assessed with BMI or with RBW. 5) The average daily energy intake was higher in the upper body obesity subjects than in the lower body obesity subjects. 6) Diabetics withing the regular exercise group had lower fasting blood glucose levels than the non-regular exercise group. Exercise did not effect the RBW, BMI, and WHR. 7) The waist-to-hip circumference ratio correlated significantly in positive with waist-circumference, but did not correlated with hip-circumference. Therefore, WHR may depended on the increased accumulation of abdominal fat in female diabetics. In conclusion, these findings suggest that caloric intake is more associated with abdominal fat accumulation in diabetic women. Blood glucose concentration is independently effected by exercise, and exercise does not affect the WHR. Therefore, control of caloric intake and development of specific exercises to change the WHR seems important for controling diabetes in female subjects.

• Journal of Nutrition and Health
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• v.31 no.3
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• pp.333-342
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• 1998

To assess the nutrient intake and diet quality of Korean adults living in rural area, dietary survey with one day 24 -hour recall method was given to 2037 subjects over 30 years of age living in Yeoncho-gun, Kyungki province of Korea, together with health survey. The mean daily energy intake was 1583 kcal, with 65.4% of energy intake being supplied by carbohydrate, 15.9% by protein and 18.7% by fat. Eighty percents of total food intake were supplied by vegetable food and the rest in the form of animal food . As well as insufficiencies in calcium and iron intake, the bioabailability of calcium and iron is considered to have been low because most of those intakes came form plant origins. For most nutrients except phosporous, proportions of subjects with intake levels less than 75% of RDA was over 40% and highest in the elderly. Those proportion of low intake among female were higher than those among male. The mean adequacy ration(MAR) , an index of overall dietary quality was 0.62 for females and 0.68 for males and decreased with increase of age. The indexes of nutritional quality (INQ) were over 1 for most nutrients except 0.06 of vitamin A, 0.73 of calcium and 0.85 of vitamin C, Nutrient intake levels less than 75% of RDA may be appropriate as a criteria for insufficiency of nutrient intake. Based on these results, it is evident that some of adults in rural areas did not consume enough nutrients, especially vitamin A, calcium and vitamin B$_2$, and that the dietary intake of female and the elderly was not adequate .