• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.10
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• pp.2773-2778
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• 1994

Tumbling motion is very effective for turbulence enhancement during compression process in the cylinder of 4-valve engines. In this paper the tumble decay mechanism for different intake port configuration were measured using laser Doppler velocimetry. Analysis of the tumble decay mechanism was achieved by means of two non-dimensional parameters, defined as tumble eccentricity and shape factor in tumble velocity profile, in addition to the tumble moment.

• Journal of Nutrition and Health
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• v.41 no.8
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• pp.887-899
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• 2008

Recently the Ministry of Health and Welfare, Republic of Korea, announced the “Dietary Guidelines for Korean Adults (DGKA)”, which includes ten Dietary Goals, six Dietary Guidelines, and twenty-three Action Guidelines. DGKA are developed as the revision of the 2003 Dietary Guidelines for Koreans, targeting adult population. Dietary Guidelines are developed for general purpose as well as for different age groups. They are revised periodically to accommodate changes in diet and health problems of the population. The process of developing new DGKA can be summarized as 1) selection of focus areas, 2) analysis and review of available data for each area selected, and 3) derivation of guidelines based on the analyzed data, and 4) finalizing the guidelines after open discussions among the experts and general public. Five focus areas were selected by examining the Nutrition Goals of the Health Plan 2010 of Korea, soliciting proposals from the experts in the related fields, and reviewing existing and international guidelines. Five areas selected were 1) adequate intake of nutrients and foods, 2) balance of energy intake and physical activities, 3) alcohol intake, 4) food security and nutrition service, and 5) food safety. Adequacy of nutrient and food intakes of the Korean adult population was assessed using 2005 Korea National Health and Nutrition Examination Survey (KNHANES) data. Newly developed Dietary Reference Intakes for Koreans were used as reference values to assess the prevalence of inadequacies and excesses in nutrient intakes. Energy balance was examined with energy intake of 2005 KNHANES survey and results of physical activity questionnaire in the survey. Alcohol intake was also examined using 2005 KNHANES results of dietary intakes as well as the results of questionnaire survey on alcohol intakes. Food security, nutrition services, and food safety were analyzed using various government data and published results on the issues. Ten Dietary Goals and six Dietary Guidelines were developed after data analysis and were subjected to reviews of experts and general public. The final DGKA are: 1) Eat a variety of foods from each food group, 2) Increase physical activity and maintain healthy weight, 3) Eat proper amount of clean foods, 4) Avoid salty foods and try to eat foods with bland taste, 5) Avoid foods with high fat contents and deep-fried foods, and 6) When you drink alcohol, limit the amount. Twenty-three action guidelines are developed in order to achieve these guidelines in actual diet and life among the population. The government is disseminating the guidelines with “337” slogan and emblem. “337” indicates everyone should practice “3” guidelines of promoting good eating practice, “3” guidelines to limit or decrease in your diet, and you should practice them for “7” days a week. The guidelines will be useful in promoting healthy food habits and good nutritional status which will result in decrease nutrition related health problems in Korea.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.469-474
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• 2002

In recent years, modularization of engine parts has increased the application of plastic products in air intake systems. Plastic intake manifolds provide many advantages including reduced weight, contracted cost, and lower intake air temperatures. These manifolds, however, have some weakness when compared with customary aluminium intake manifolds, in that they have low sound transmission loss because of their lower material density. This low transmission loss of plastic intake manifolds causes several problems related to flow noise, especially when the throttle is opened quickly. The physical processes, responsible for this flow noise, include turbulent fluid motion and relative motion of the throttle to the airflow. The former is generated by high-speed airflow in the splits between the throttle valve and the inner-surface of the throttle body and surge-tank, which can be categorized into the quadrupole source. The latter induces the unsteady force on the flow, which can be classified into the dipole source. In this paper, the mechanism of noise generation from the turbulence is only investigated as a preliminary study. Stochastic noise source synthesis method is adopted for the analysis of turbulence-induced, i.e. quadrupole noise by throttle at quick opening state. The method consists of three procedures. The first step corresponds to the preliminary time-averaged Navier-Stokes computation with a $k-\varepsilon$ turbulence model providing mean flow field characteristics. The second step is the synthesis of time-dependent turbulent velocity field associated with quadrupole noise sources. The final step is devoted to the determination of acoustic source terms associated with turbulent velocity. For the first step, we used market available analysis tools such as STAR-CD, the trade names of fluid analysis tools available on the market. The steady state flows at three open angle of throttle valve, i.e. 20, 35 and 60 degree, are numerically analyzed. Then, time-dependent turbulent velocity fields are produced by using the stochastic model and the flow analysis results. Using this turbulent velocity field, the turbulence-originated noise sources, i.e. the self-noise and shear-noise sources are synthesized. Based on these numerical results, it is found that the origin of the turbulent flow and noise might be attributed to the process of formulation and the interaction of two vortex lines formed in the downstream of the throttle valve. These vortex lines are produced by the non-uniform splits between the throttle valve and inner cylinder surface. Based on the analysis, we present the low-noise design of the inner geometry of throttle body.

• Research in Community and Public Health Nursing
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• v.11 no.2
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• pp.358-372
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• 2000

The purpose of this study was to describe the way of life (such as smoking habits, alcohol consumption, exercise, duration of sleep, eating habits etc.), physical. psychological and overall health complaints and to identify the relationship between the way of life and health complaints of the nursing students. Data was collected with the self-administered OMI( Okayama Medical Index Health Questionnaire, devised Cornell Medical Index) from 766 nursing students and was analyzed. For data analysis, descriptive statistics and an ANOVA with an SPSS/PC+ program were used. The results were as follows: 1. The mean age of subjects was 21.0557(2.7618) years old in their 1st, 2nd, 3rd and 4th year-classes of nursing departments and college students in 4 regions of Korea. 62.1% of subjects were of the proper body weight, 2.0% were overweight, and 28.3% were underweight. Most subjects did not have a past history of disease, but 1.8% of subjects had experienced a blood transfusion. 2. 28.3% of the subjects had averaged 7 hours of sleep, 98.5% were nonsmokers, 91.2% were nondrinkers, 74.7% of subjects had milk intake sometimes, 53.7% of the subjects had an average salt intake, 49.6% of the subjects usually had a green vegetable intake, 45.4% of the subjects sometimes had fatty food intake, 64.8% of the subjects had good taste, 29.5% of the subjects enjoyed physical exercise. 3. The highest percentages of 'yes' among physical. psychological and overall health complaints were observed in the question 'Do you have gastric pain?'(60.2%), 'Are you confused of disorderly?' (37.2%), 'Physical body was burdensome and fatigued.'(57.3%). 4. The total O.M.I. score ranged from 1 to 89 with an average of 22.91(SD=12.10). A statistically significant difference was observed for the physical. psychological complaints for alcohol consumption. and for the psychological complaints for salt and fatty food intake. These conclusions should provide grounds for future studies of strategies for health promoting lifestyle for nursing students and their health concerns. Further research is required to investigate the life environmental and psychological factors affecting the way of life for nursing students and their health status, to analyze the health behavior of nursing students related with their culture and consciousness. Also epidemiologic research methodology, such as prospective cohort study should be considered to explore the performing process of nursing student's health behavior related with the occurrence of diseases.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.7
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• pp.953-960
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• 2019

The Miller cycle is a diesel engine that has been developed in recent years that it can reduce NOx and improve fuel consumption by reducing the compression ratio through intake valve closing (IVC) time control. The Miller cycle can be divided into the early Miller method of closing the intake valve before the bottom dead center (BDC) and the late Miller method of closing the intake valve after the BDC. At low speeds, the late Miller method is advantageous as it can increase the volumetric efficiency; while at medium and high speeds, the early Miller method is advantageous because of the high internal temperature reduction effect due to the expansion of the intake air during the piston lowering from IVC to BDC. Therefore, in consideration of the ef ects of the early and late Miller methods, it is necessary to adopt the most suitable Miller method for the operating conditions. In this study, a two-stage turbo charge system was applied to four-stroke engines and the process of enhancing the Miller effect through a reduction of the intake and exhaust valve overlap as well as the valve change adjustment mechanism were considered. As a result, the ef ects of fuel consumption and Tmax reduction were confirmed by adopting the Miller cycle with a two-stage supercharge, a reduction of valve overlap, and an increase of suction valve lift.

• Journal of the Korean Society of Food Culture
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• v.14 no.2
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• pp.155-165
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• 1999

The issue of health and nutritional wellbeing becomes one of the utmost concerns for the welfare of the elderly in a society of increased aging populations. This study was conducted to assess nutritional state and to identify possible dietary factors that might influence health and nutritional state of the free living elderly women. Two hundred sixty two elderly women, aged 60-90 who are actively participating in a continuing education program for the elderly in Seoul area, were interviewed using a dietary habit questionnaire and a 24-hour recall. Anthropometric measurements such as heights, weights, body mass index, and tricep skinfolds and dental status were significantly different between the two age groups, <75 and ${\geq}$ 75 years of age. Sixty eight percent of the subjects were using nutritional supplements regularly, in the descending order of vitamin-mineral supplements(40%), botanicals(27.6%), tonic drinks(16%), and health foods(13.2%). For hot beverages, our study subjects drank coffee (33.6%) and green tea (17.9%) frequently, followed by doongulae, job's tears, citron and kyulmyung tea. With regard to micronutrients, vitamin C intake was found to be lower in the group aged over 75 compared to that below 75 (p<0.05). Calcium intake was significantly higher among the elderly with good dental status followed by the groups with gingivitis, denture, and missed teeth with poor chewing abilities (p<0.05). The amount of personal spending money was found to be a significant contributing factor (p<0.05) to the energy and nutrient intake in an individual. The results of the present study can be applied to the identification of the possible factors that might intervene the aging process, to the planning of the nutrition education program, and to the development of health food products for the promotion of health and nutrition of the elderly women.

• Nutrition Research and Practice
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• v.14 no.3
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• pp.262-275
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• 2020

BACKGROUND/OBJECTIVES: Evidence-based customized nutritional interventions are required for effective treatment of moderate to severe obese children and adolescents. SUBJECTS/METHODS: Sixty six (64.1% of 103) of the eligible participants who joined the usual care or physical activity group in the clinic were involved in 16-week intervention. Customized nutritional intervention was implemented for each participant based on a nutrition care process (NCP) model. Sociodemographic assessment, anthropometrics data, health- and dietary-related behaviors, and dietary intake of the study subjects were assessed at baseline and follow-up. All participants engaged in 30-minute nutritional sessions on a monthly basis. RESULTS: After 16 weeks, there were significant improvements in body composition [BMI (-0.8 ± 0.9, P < 0.05), BMI z-score (-0.3 ± 0.2, P < 0.001), body fat (kg) (-1.3 ± 2.1, P < 0.05), and body fat (%)(-1.5 ± 1.9, P < 0.05)] as well as macronutrient intake [total energy intake (kcal) (-563.7 ± 656.8, P < 0.05), energy (%) (-26.5 ± 30.0, P < 0.05) and fat (g) (-28.3 ± 40.6, P < 0.05)] in the adherent group than the non-adherent group. The SOC was higher in both groups after the intervention (P < 0.001). CONCLUSIONS: Our results highlight the positive effects of an evidence-based approach as a multidisciplinary intervention for people-centered nutritional care and weight management.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.5
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• pp.426-437
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• 2007

off-design conditions, supersonic air inlets often encounter the problem of aerodynamic instability, called inlet buzz, which causes the significant degradation of the engine performance. An experimental and numerical study was conducted to investigate the phenomenon of supersonic inlet buzz on a generic, axisymmetric, external-compression inlet with a single-surface center-body. It is understood the mechanism of buzz onset as proving that the origin of buzz is the flow choking induced by separation at the intake throat. Also it is observed the intermittent and continuous buzz mode as area ratio varies and understood the transition process through this study. The buzz frequency become to be higher as decreasing the area ratio, but for each area ratio, the frequency of pressure oscillation is the same at all points of intake.

• The Korean Journal of Food And Nutrition
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• v.27 no.4
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• pp.570-580
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• 2014

The purpose of this study was to investigate the effect of calcium (Ca) and vitamin D (vit. D) levels on metabolism of various minerals such as Ca, P, Mg, Fe, Zn, Cu, and Cr. The comparison was made on the rats that were placed on diet containing powdered skim milk with different Ca and vit. D levels for 5 weeks. A total of 42 5-week-old Sprague-Dawley rats were divided into 7 groups as follows: Control group consisted of normal Ca and normal vit. D (0.5% Ca, 1,000 IU vit. D); Experimental groups were divided into low (0.25%) and high (1.0%) calcium levels; and vit. D group was divided into low (10 IU), normal (1,000 IU), and high (5,000 IU) subgroups. The weight gain and food efficiency ratios of the rats were not significantly different with increasing dietary Ca levels. The absorption rates of 7 minerals (Ca, P, Mg, Fe, Zn, Cu, and Cr) were significantly decreased with increasing dietary Ca levels. Also, fecal excretion of P significantly increased with increasing dietary vit. D levels (p<0.05), and urine excretion of Fe was significantly increased with increasing dietary vit. D levels (p<0.001). The result indicated that higher Ca intake affected on bioavailability of other minerals, due to interactions among minerals in the process of intestinal absorption. However, vitamin D intake had no effect on bioavailability of several minerals. Therefore, it could be suggested that adequate Ca intake is important for balance of the minerals.

• Parasites, Hosts and Diseases
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• v.48 no.3
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• pp.219-224
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• 2010

This study has been conducted to estimate the occurrence of Cryptosporidium oocysts in water supplies in the Metropolitan area of Seoul, South Korea, for 10 years from 2000 to 2009. Water samples were collected quarterly at 6 intakes in the Han River and its largest stream and 6 conventional Water Treatment Plants (WTPs) serving drinking water for 10 million people of Seoul. Cryptosporidium oocysts were found in 22.5% of intake water samples and arithmetic mean was 0.65 oocysts/10 L (range 0-22 oocysts/10 L). Although the annual mean of oocyst number was as low as 0.04-1.90 oocysts/10 L, 3 peaks in 2004 and 2007 were observed and the pollution level was a little higher in winter. The lowest density was observed at Paldang intake and the pollution level increased at Kuui and Jayang intakes. At the end of the largest stream, oocysts were found in 70% of collected samples (mean 5.71 oocysts/10 L) and it seemed that its joining the Han River resulted in the increase at Kuui intake and downstream. Oocyst removal by physical process exceeded 2.0-2.3 log and then all finished water samples collected at 6 WTPs were negative for Cryptosporidium in each 100 L sample for 10 years. These results suggested that domestic wastewater from the urban region could be a source of Cryptosporidium pollution and separating sewage systems adjacent to the intakes could be meaningful for some intakes having weakness related to parasitological water quality.