• 한국분무공학회지
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• 제17권2호
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• pp.94-99
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• 2012

The characteristics of spray behavior and injected amount were studied with two types of nozzles for using in a compression ignition engine with dual fuel technology for construction machines. A penetration length of spray tends to shorten due to a decrease of injected amount of a diesel fuel with dual fuel engine application. In order to ignite the gaseous fuel premixed with air during intake process, a diesel fuel, which was compression ignited, needs to penetrate somehow similar depth compared with the case of a diesel fuel-only-injection. In this work, a nozzle with reduced hole diameter and increased number of holes was tested and demonstrated that, compared to diesel 100% case, its penetration lengths are comparable to 74% and 79%, respectively, of those of 100% and 50% supply of a diesel fuel with the baseline nozzle that has four holes and 30.4% increased diameter. This will presumably enhancement the combustion in a dual fuel engine. A design suggestion was also made in this work to achieve similar penetration length of spray with diesel 100% case to prevent combustion from being deteriorated in a dual fuel engine.

• 지역사회간호학회지
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• 제27권4호
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• pp.337-345
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• 2016

Purpose: This study aims at identifying individual- and school-level factors associated with unintentional injuries to Korean adolescents at school by applying multilevel modeling. Methods: From the database of the eleventh Korea Youth Risk Behavior Web-based Survey (KYRBS), the researchers selected 68,043 adolescents from the $7^{th}$ to the $12^{th}$ grades. Data were analyzed using ${\chi}^2$ test for prevalence and multilevel modeling for related factors of unintentional injuries at school. Results: About 22.9 percent of the adolescents had treatment experiences for unintentional injuries at school in the past 12 months. At the individual level, the significant factors associated with unintentional injuries at school included gender, grade, academic achievement, current smoking, alcohol consumption, frequency of high caffeine intake, depression, and relief of fatigue after sleep. At the group level, the significant factors included number of physical education per week and safety education. Conclusion: School based injury prevention programs should be sensitive to both individual- and school-level factors associated with unintentional injury at school among Korean adolescents.

• Preventive Nutrition and Food Science
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• 제7권4호
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• pp.442-446
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• 2002

Differences in dietary habits between Korean smokers and non-smokers were investigated using information obtained from 7,370 adults, aged 20 years and older who participated in the 1998 Korean National Health and Nutrition Sulvey. Dietary habit data including: skipping of meals, meal regularity, meal volume, snacking habits, removing fatty portions before eating foods, and dietary supplement intake were collected using a structured questionnaire by interview. Individual smoking data was also collected by interview as part of the health behavior survey. A Chi-square test was used to test the association between the dietary habits and smoking. 66.9% of the men were smokers (daily current or occasional current), while only 6.7% of women smoked. On average, 34.7% of the subjects were smokers. Smokers were more likely than nonsmokers to engage in the following dietary habits considered unhealthy: skipping breakfast, meal irregularity, large dinners, small breakfasts, frequently eating out, and eating food without removing the fatty portion. Therefore, Korean smokers should be provided education to assist them in making healthy dietary choices such as: eating regular meals, small dinners, and removing fatty Portion of foods. The survey also revealed that a substantial percentage (about 20%) of the subjects were taking some kind of dietary supplement, regardless of smoking status. It is, therefore, alto necessary to inform the general public that a balanced diet is the ideal way to obtain nutrients for optimal health.

• International Journal of Human Ecology
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• 제4권1호
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• pp.71-86
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• 2003

Over the past few decades, changes in patterns of behavior (e.g., diet, smoking, alcohol consumption, and physical activity) have led to major changes in health status, characterized by increases in obesity, Type II diabetes mellitus, cardiovascular disease, and some cancers. This epidemiologic transition is largely the result of rapid increases in immigration to developed countries and rural-urban migration within developing countries, which is usually accompanied by environmental and lifestyle changes. In particular, adoption of “Western” dietary patterns, which tend to be high in fat and low in fruits and vegetables, is of concern since diet is a potent contributor to chronic disease risk. However, until recently, the process by which immigrants and rural-urban migrants adopt the dietary practices predominant in their new environments, known as dietary acculturation, has received very little research attention. Dietary acculturation is multidimensional, dynamic, and complex, and varies considerably depending on a variety of personal, cultural, and environmental characteristics. Therefore, to intervene successfully on the negative aspects of dietary acculturation, it is important to understand the process and identify factors that predispose and enable it to occur. The purpose of this article is to provide a practical model for understanding and investigating the effect of dietary acculturation on food and nutrient intake. Thus, this report 1) gives an overview of acculturation, 2) defines dietary acculturation and presents a model for how it occurs, 3) discusses measurement issues around dietary acculturation,4) reviews the literature on dietary acculturation in Korean Americans; 4) suggests a paradigm for acculturation research; and 5) offers some recommendations for future research in this area.

• 한국치위생학회지
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• 제15권4호
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• pp.593-602
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• 2015

Objectives: The purpose of the study is to investigate the relations between oral health status and subjective oral health recognition in Korean adolescents. Methods: The survey data were extracted from the 2012 Korea National Oral Health Survey from June to November, 2012. The survey consisted of oral checkup data and the oral health interviewing data of 9,981 adolescents(5,335 male, 4,646 female) by proportional distribution. The questionnaire included general objective oral health status and subjective oral health recognition. The subjective oral health recognition consisted of general characteristics of the subjects, oral health status, oral health behavior, and subjective oral health recognition. Results: According to multiple regression analysis for the relations between general characteristics and subjective oral health recognition, subjective health recognition, the influencing factors were gender, age, the number of tooth brushing per day, intake of snacks and carbonated drinks, regular oral examination, decayed teeth (DT), missing teeth (MT,) and DMFT. Conclusions: The routine oral checkup is the most important method to improve the oral health management in the adolescents. The continuing oral health improvement project must be implemented based on the law and will keep the adolescents in good oral health status.

• 한국보건간호학회지
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• 제29권2호
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• pp.177-189
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• 2015

Purpose: The purpose of this study was to investigate bone mineral density (BMD) and risk factors related to osteopenia in community people. Methods: The subjects consisted of 145 community people. The variables of osteoporosis knowledge and preventive health promoting behavior were measured using questionnaires. BMD and BMI (body mass index) were measured. Dietary nutrients intake related to osteoporosis was measured using 24hours recall. Data analysis was performed using the SPSS 18.0 program, using mean, standard deviation, ${\chi}^2-test$, t-test, and logistic regression. Results: Eighty six people (59.3%) had an osteopenia. According to normal group and osteopenia group, there was significant difference in gender (${\chi}^2=6.72$, p=.010) and smoking (${\chi}^2=5.18$, p=.023). Predictors of osteopenia group were male (OR=2.65, CI=1.03-8.98), BMI(OR=0.86, CI=0.72-0.96). Conclusion: Health care providers must consider factors that affect osteopenia such as gender, BMI. These results suggest the need to instruct nursing activities and interventions which are beneficial for prevention of osteoporosis.

• 한국자동차공학회논문집
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• 제13권1호
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• pp.9-18
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• 2005

The objective of this study is to analyse the spray characteristics according to the injection duration under the ambient pressure condition, and the injection timing in the visualization engine. In order to investigate the spray behavior, we obtained the spray velocity using the PIV method that has been an useful optical diagnostics technology, and calculated the vorticity from spray velocity component. These results elucidated the relationship between vorticity and entropy which play an important role in the diffusion process for the early injection case and the stratification process for the late injection case. In addition, we quantified the homogeneous diffusion rate of spray using the entropy analysis based on the Boltzmann's statistical thermodynamics. Using these method, it was found that the concentration of spray droplets caused by the increase of injection duration is more effective than the increase of momentum dissipation. We also found that the homogeneous diffusion rate increased as the injection timing moved to the early intake stroke process and BTDC $50^{\circ}$ was the most efficient injection timing for the stratified mixture formation during the compression stroke.

• Journal of Biosystems Engineering
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• 제38권2호
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• pp.129-137
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• 2013

Purpose: Modeling has been used for elucidating the mechanism of complex biosystems. In spite of importance and uniqueness of adolescent calcium (Ca) metabolism characterized by a threshold Ca intake, its regulatory mechanism has not been covered and even not proposed. Hence, this study aims at model-based proposing potential mechanisms regulating adolescent Ca metabolism. Methods: Two different hypothetic mechanisms were proposed. The main mechanism is conceived based on Ca-protein binding which induces renal Ca filtration, while additional mechanism assumed that active renal Ca re-absorption regulated Ca metabolism in adolescents. Mathematical models were developed to represent the proposed mechanism and simulated them whether they could produce adolescent Ca profiles in serum and urine. Results: Simulation showed that both mechanisms resulted in the unique behavior of Ca metabolism in adolescents. Based on the simulation insulin-like growth factor-1 (IGF-1) is suggested as a potential regulator because it is related to both growth, a remarkable characteristic of adolescence, and Ca metabolism including absorption and bone accretion. Then, descriptive modeling is employed to conceptualize the hypothesized mechanisms governing adolescent Ca metabolism. Conclusions: This study demonstrated that modeling is a powerful tool for elucidating an unknown mechanism by simulating potential regulatory mechanisms in adolescent Ca metabolism. It is expected that various analytic applications would be plausible in the study of biosystems, particularly with combination of experimental and modeling approaches.

• 한국초지조사료학회지
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• 제8권3호
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• pp.68-76
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• 1988

The variation of rumination response in steers fed a same amount of orcharugrass hay was investigated. With three steers (6, 12, 24 months) of the Japanese Black Breed, rumination behaviour was measured continuously during a 5 days period by masseter EMG telemetry system. The results are summarized as follows: 1. The average daily rumination time of respective animals were 438,447 and 433 min. with small daily variation both within and among animal. But the rumination time per DM kg of hay consumed varied from 66 to 138 min., and calf spent longer than older calf. 2. Actural chewing time showed small variation, and percentage of actural chewing time spent in rumination time was from 88 to 93% on individual average. 3. The daily number of chewing in rumination was approximately 25,000 to 30,000 with large individual differences. The chews per DM kg intake varied from 3,800 to 9,600, and calf chewed more than older calf. 4. The average rate of chewing per 100 sec. (chewing speed), there was a large difference between animals i.e. 104, 114, 131 respectively, but very little variance between days in individual. 5. No relation between day to day variations in eating time and rumination behavior, but significantly positive correlation was observed in the relation among rumination time, chewing time, No. of boluses and No. of chews. 6. Active time of day in rumination altered considerably day to day, but variation in the amount of rumination per day as expressed by the rumination time was relatively small.

• 한국축산시설환경학회지
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• 제20권4호
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• pp.173-176
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• 2014

This study was conducted to investigate the effect of weaning period on the vocalization frequency of Hanwoo calf. Twelve Hanwoo calves were allocated into 4 groups, control (forced weaning on 90days) and treatment (weaning on 70, 90 and 120days with 5 adaptation days). After weaning, behavior and vocalization of Hanwoo calves were recorded on 3 consecutive days with closed circuit television (DTC-R5254, Digite Co., Ltd., Korea) and digital audio tape recorder (SR-900, Idamtech Co., Ltd., Korea). Vocalization frequency of Hanwoo calf were not significance difference with control and treatment group. Thus, additional studies of feed intake and body weight gain were needed to determine the weaning period of Hanwoo calves.