• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.733-742
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• 2016

In recent years, gas engines fueled with LNG or synthetic gas have been attracting considerable attention for marine use owing to their potential to facilitate better fuel economy and to reduce emissions. It has been confirmed that gas engines using the Otto cycle, which involves premixed combustion, can satisfy Tier III regulations without the EGR or SCR system. The objective of this study is to acquire simulation technologies for predicting gas engine performances in industrial fields. Using the commercial software BOOST, the simulation is conducted on a gasoline engine rather than a marine engine due to the gasoline engine's easier accessibility. This study consists of two stages. In the first stage published previously, the optimal modeling techniques for representing the behavior of the gas in the intake and exhaust systems were determined. In the current study, we formulated a method to evaluate the combustion and heat transfer processes in the cylinder and to ultimately determine the major performance parameters, given that the analytical model derived from the previous stage has been applied. Through this study, we were able to determine a combustion and heat transfer model and a valve discharge coefficient that are less reliant on empirical data: we were also able to formulate a methodology through which relevant constants are decided. We confirmed that the values of transient cylinder pressure variation, indicated mean effective pressure, and air supply can be successfully predicted using our modeling techniques.

• Korean Journal of Community Nutrition
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• v.17 no.2
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• pp.226-242
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• 2012

Consumption of foods with high energy and low nutrient values has been linked to various health issues including obesity and chronic diseases. This study investigated the high-energy/low-nutrient food consumption status and its relationship with obesity status and intake of energy and nutrients, using the Korea National Health and Nutrition Examination Survey (KNHANES) and the Korea Youth Risk Behavior Web-based Survey (KYRBWS). The prevalence of overweight and obesity among 2-18 year-olds was 8.4% and 10.8% in 2008 and 8.5% and 9.0% in 2009, respectively, in KNHANES. The prevalence of obesity among 12-18 year-olds was 13.9% in 2008 and 11.4% in 2009 in KNHANES, while it was 8.1% in 2008 and 8.2% in 2009 in KYRBWS. Consumption patterns of high-energy/low-nutrient foods were diverse depending on the particular food type. High-energy/low-nutrient foods such as cookies were most often consumed more frequently (2~3 times per week), but fast food type foods were generally consumed less frequently (once per week or less). No significant relationships between highenergy/ low-nutrient food consumption and level of energy and nutrient intakes were found in either datasets. Adolescents who were not obese more frequently consumed ramen (p < 0.001), cookies (p < 0.001) and fast food (p < 0.001) than those who were obese in KYRBWS, however, such relationships were not found in KNHANES. This direction of the relationship could be probably attributed to the cross-sectional nature of the datasets. This study was limited by the cross-sectional nature of the data, therefore, further longitudinal research using various study techniques would be necessary to understand the effects of high-energy/low-nutrient foods on child obesity.

• Analytical Science and Technology
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• v.26 no.3
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• pp.174-181
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• 2013

Pyrifluquinazon is classified with a quinazoline insecticide that regulates food intake by controling the feeding behavior acting on the endocrine or nervous system of pests such as aphids and white fly. To keep safety on pyrifluquinazon residues in agricultural commodities a simple, accurate and rapid analytical method was developed and validated using high performance liquid chromatograph (HPLC-UVD). The pyrifluquinazon residues acidified with 1% formic acid in samples were extracted with acetonitrile and partitioned with hexane subsequently to dichloromethane then purified with silica solid phase extraction (SPE) cartridge. The purified samples were detected using HPLC-UVD. The method was validated using apple and pear spiked with pyrifluquinazon at 0.02, 0.05 and 0.1 mg/kg and hulled rice, pepper, soybean at 0.05 and 0.1 mg/kg. Average recoveries were 70.5~107.9% with relative standard deviation less than 10%. The result of recoveries and overall coefficient of variation of a laboratory results in Gwangju regional FDA and Daejeon regional FDA was followed with Codex guideline (CODEX CAC/GL 40). This method is appropriated at pyrifluquinazon residues determination and will be used as official method of analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5049-5055
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• 2011

The purpose of this study is to emphasis the fact that the oral cavity should be well-managed as it is where the intake of the valuable nutrition for the baby is made, among many other important factors and changes that the pregnant women go through as they prepare for the birth of a human being for 10 months. For this, we surveyed the management of the oral hygiene and the awareness of oral health by the pregnant women. The result showed that the nauseating during the brushing of the teeth and the use of the oral hygienic products varied among different standard of lives with statistical significance. As for the standard of living, those in higher level showed also a higher level of the use, while the middle and low standard of living showed lower level of usage of the oral hygienic products. In case of the dental treatment during the pregnancy, most of the interviewees answered they do not receive dental treatment during pregnancy in the fear of bad influence on the baby and the potential risk of congenital anomaly. The perceived necessity of the education on the oral health was generally high. And, for the contents of such education, they preferred the timing of the dental treatment, the content of the treatment, and misunderstandings regarding the dental treatment.

• Journal of Korean Home Economics Education Association
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• v.33 no.1
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• pp.151-167
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• 2021

This study reports on the development of a dietary education program for Korean young adults in single-person households. The 7th National Health and Nutrition Survey (2016-2018) was used to compare and analyze the dietary behavior of single-person households and multi-person households, and an online survey was conducted on 350 young adults (age 19-39 years) living in Seoul. According to the analysis, single-person households had higher rates of breakfast and eating out than multi-person households, and significantly lower average intake of energy and nutrients (p<0.05). In particular, in the case of single-person households, the lower the frequency of cooking at home, the higher the rate of breakfast and the higher the frequency of eating out and delivery food (p<0.05). Based on the survey, a dietary education program for young adults single-person households was developed by applying the DESIGN six-step procedure and social cognitive theory as a conceptual model. The first session consisted of the health and economic benefits of home-cooked meals, the second session of the importance of the breakfast and the effect of exercise in life, the third session of the importance of balanced nutrition and the principles of a healthy diet, the fourth session of food safety and storage, and the fifth session of social dining. Each session was composed of a combination of theoretical lectures to motivate 'more making and eating healthy home-cooked meals' and cooking practice for improving behavioral performance.

• The Journal of the Korea Contents Association
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• v.19 no.8
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• pp.106-114
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• 2019

The study was conducted to investigate the effect of whole-wheat ratio and nutrition information provision on purchasing behavior and consumer intention among individuals in their twenties who lack calcium intake. In the end, this study aims to provide basic data on the development and marketing strategy of customized nutrition-reinforced snacks. Regarding whole wheat ratios, the acceptance of taste of whole wheat flour was highest in ZF but didn't seem significant difference with HF's. The familiarity of taste and flavor (P <0.001), purchase intention (p <0.001) and recommendation intention (p <0.001) were higher in order of ZF, HF and TF. Regarding information provision, familiarity of taste and flavor (P <0.05), purchase intention (p <0.05) and recommendation intention (p <0.05) were higher in order of detailed information group, non - information group and simple information group. Therefore, developing calcium-fortified biscuit, mixing whole wheat flour with normal flour might reduce consumer's resistance, Also, providing detailed information on the degree of fortification of calcium and dietary fiber might cause a synergistic effect on consumption.

• Korean Journal of Community Nutrition
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• v.24 no.4
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• pp.300-308
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• 2019

Objectives: This research was conducted to identify the consumers' food choice factors that affect the consumers' replacement of soft drinks with carbonated water. Methods: The present study used secondary data from a consumer panel survey conducted by the Rural Development Administration of Korea, and the data included the panel members' purchase records based on their monthly spending receipts. The survey asked the participants about their food choice factors and their personal responsibility for their health. This survey included independent variables for the consumers' food purchase factors. As a dependent variable, two types of groups were defined. The replacement group included those people who increased their purchase of carbonated water and decreased their purchase of soft drinks. The non-replacement group included those people who did not change their purchase patterns or they increased their purchase of soft drinks and they decreased their purchase of carbonated water. Logistic regression analysis was conducted to determine the consumers' food choice factors that were associated with replacing soft drinks with carbonated water. Results: The replacement group was significantly associated with (1) a younger age (OR=0.953), (2) being a housewife (OR=2.03), (3) higher income (OR=1.001) and (4) less concern about price (OR=0.819) when purchasing food. This group also showed (5) higher enjoyment (OR=1.328) when choosing food and (6) they took greater responsibly for their personal health (OR=1.233). Conclusions: This research is the first study to mainly focus on soft drinks and carbonated water. The result of this research showed that young, health-conscious consumers with a higher income and who are more interested in food have more possibilities to replace soft drinks with carbonated water. These research findings may be applied to consumers who have characteristics that are similar to the young health-conscious consumers and the results can help to suggest ways to reduce sugar intake and improve public health. However, this research has a limitation due to the application of secondary data. Therefore, a future study is needed to develop detailed survey questions about food choice factors and to extend these factors to all beverages, including soft drinks made with sugar substitutes, so as to reflect the growth of alternative industries that use artificial sweeteners or different types of sugar to make commercially available drinks.

• Journal of Korean Home Economics Education Association
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• v.34 no.1
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• pp.113-129
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• 2022

This study evaluated the dietary habits and dietary quality of the Korean elderly according to muscle strength status. This study was conducted on the elderly aged over 65 years who participated in the 2014-2018 Korea National Health and Nutrition Examination Survey. Subjects were classified into the normal muscle strength group(n=2,000) and the low muscle strength group(n=1,273) according to the handgrip strength. There was a significant difference in general characteristics, diet habits, and health behavior according to the muscle strength status. The normal muscle strength group had a higher total score of KHEI and a subtotal score of 「adequacy」 items. But there was not significant difference in the 「moderation」 items. For the 「balance of energy intake」 items, the normal muscle strength group had a higher subtotal score than the low muscle strength group only in among women. The prevalence of low muscle strength decreased in the highest quartile of the adjusted KHEI total score(p for trend=0.08). As a result of this study, it was found that KHEI was significantly associated with muscle strength. This study result can be used to provide dietary guidelines for the improvement of muscle strength in the elderly based on each item of KHEI and sex.

• Journal of the Korean Society of Food Culture
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• v.25 no.3
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• pp.285-295
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• 2010

The purpose of this study was to compare the awareness of dietary patterns and health of full-time and employed housewives. The investigation gathered information on general characteristics, dietary lifestyle, nutritional status, and health by questionnaire as well as anthropometric measurements. The subjects included housewives living in Seoul and Gyeonggi Province (86 full-time and 127 working housewives) during November 2009 to January 2010. The average age, height, and weight of the housewives were $45.8{\pm}7.6\;yr$, $161.0{\pm}8.4\;cm$, and $55.7{\pm}6.3\;kg$, respectively. The average monthly income of the households was 3 million to 5 million won (31.4% full-time and 37.0% working housewives), and their average food expense was 200,000 to 500,000 won (46.5% full-time and 48.1% working housewives). More than 90% of the studied homes were nuclear families and the most common number of children was 2 to 3 (79.1% full-time and 76.4% working housewives). The ratio of employed housewives who ate regular meals was 35.4%, but that of the full-time housewives was 48.2% (p<0.05). Of the working housewives, 7.1% never ate breakfast and the primary reason for skipping breakfast was 'busy in the morning' (61.1%). The type of food that the housewives preferred when eating out was Korean food, both for the full-time and employed housewives (76.0%). All the housewives overate calories and the full-time housewives ate more protein, fat, vitamin A, vitamin B1, vitamin B6, niacin, vitamin C, vitamin E, folic acid, and cholesterol than the employed housewives (p<0.05). Both the full-time and employed housewives were more satisfied with supper than with other meals. About 30.6% of the full-time and 33.9% of the working housewives had no interest in health, but answered that regular exercise was very important for health (33.3% full-time and 39.7% working housewives). In conclusion, working housewives have poor dietary habits and nutrient intakes, thus substantial measures to improve these problems are urgently needed.

• Journal of Animal Science and Technology
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• v.66 no.1
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• pp.135-144
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• 2024

The objective of this study was to investigate the influence of feeding frequency on a sow's reproductive performance and stress response during gestation. A total of twenty multiparous sows (Yorkshire × Landrace) were used in a completely randomized design based on their parity, body weight (BW), and backfat thickness (BFT), and the sows were allotted to two different feeding systems: 1) once daily feeding (OF) and 2) twice daily feeding (TF) in corn-soybean meal based diets. The gestation diet was formulated to contain 3,265 kcal of metabolizable energy (ME) / kg, 12.90% of crude protein (CP), and 0.75 % of total lysine. The lactation diet was formulated to contain 3,265 kcal of ME / kg, 16.80% of CP, and 1.08% of total lysine and provided ad libitum during lactation. In gestation, sow BFT and BF changes were not affected by feeding frequency, but higher BW and BW gain from day 35 to 90 and day 35 to 110 were observed in OF sow (p < 0.10). In lactation, feeding frequency did not influence on BW, BW gain, BFT, BF changes, average daily feed intake, and wean-to-estrus interval. Also, there were no differences in litter size, litter weight and piglet weight in lactating sows. OF sows had higher (p < 0.05; p < 0.10) protein, solid-not-fat, and total solid concentrations in colostrum compared to TF sows, while OF sows had a lower (p < 0.05) lactose concentration in colostrum compared to TF sows. Sows in OF showed significantly lower average daily water consumption (ADWC) from day 35 to 110 of gestation (p < 0.05). While there were no significant differences in stereotypic behaviors and salivary cortisol levels during gestation between treatments, the OF sows showed less time spending on the activity at day 105 (p < 0.05). In conclusion, reduced feeding frequency increased BW gain during gestation, decreased activation time, and changed the colostrum composition. This information may contribute to the understanding of the physiological and behavioral change of gestating sows by manipulating feeding frequency.