• 한국환경과학회지
• /
• 제27권6호
• /
• pp.425-436
• /
• 2018

To establish initial response scenarios for nuclear accidents around the Kori nuclear power plants, the potential for radionuclide diffusion was estimated using numerical experiments and statistical techniques. This study used the numerical model WRF (Weather Research and Forecasting) and FLEXPART (Flexible Particle dispersion model) to calculate the three-dimensional wind field and radionuclide dispersion, respectively. The wind patterns observed at Gijang, near the plants, and at meteorological sites in Busan, were reproduced and applied to estimates of seasonally averaged wind fields. The distribution of emitted radionuclides are strongly associated with characteristics of topography and synoptic wind patterns over nuclear power plants. Since the terrain around the power plants is complex, estimates of radionuclide distribution often produce unexpected results when wind data from different sites are used in statistical calculations. It is highly probable that in the summer and autumn, radionuclides move south-west, towards the downtown metropolitan area. This study has clear limitations in that it uses the seasonal wind field rather than the daily wind field.

• 한국자기공명학회논문지
• /
• 제16권2호
• /
• pp.91-102
• /
• 2012

Metabolomics is the systematic identification and quantification of all metabolites in an organism or biological sample. NMR has been used as a major application tool in plant metabolomics such as quality control, chemotaxonomy, and analysis of genetically modified plants. Herbal medicines are the important therapeutics and are used to manage common diseases such as cold, inflammation, pain, heart diseases, liver cirrhosis, diabetes and central nerve system diseases. Herb plants include various kinds of species such as geranium, mint, and thyme and so on and contain different kinds of metabolites. We performed NMR-based metabolomics study on the seven different species of herb plants using $^1H$ NMR experiments and OPLS-DA to understand the correlation between the classification of herb plants and their metabolite contents. This study showed clear metabolic discrimination among various herb plants. This metabolmics study found several diagnostic NMR signals which are able to be used as bio-markers for identification of the specific herb plants among various species. Clear metabolic discrimination of herb plants suggests three chemotaxonomic groups of herb species.

• 대한치과기공학회지
• /
• 제33권4호
• /
• pp.495-503
• /
• 2011

Purpose: The purpose of this study was to obtain data that can be utilized in the planning of oral health education plan, by surveying the correlation between oral health knowledge, attitude, and behavior among high grade students elementary school in some regions of the metropolitan. Methods: The subject of this study through the survey of the recognition of the oral health, a questionnaire survey was conducted for 548 male and female students who were in the 4th, 5th, 6th grade of elementary school in some regions of the metropolitan. Statistical analysis was conducted using the SPSS 12.0 with t-test, ANOVA, and correlation. Results: Knowledge of oral health was very high. Correct attitudes and positive behavior were indicated. There was a significant difference in oral health knowledge according to school year and parents' dental condition(P<.05). The student one recording oral health behavior degree where the oral health knowledge is high appears highly, considers statistically the difference which it was visible. Positive correlation was significantly observed among oral health knowledge, attitudes, and behavior. Especially, attitudes and toothbrush method were highly correlated(r=.853). Conclusion: Oral health program through the elementary school students and their parents for the development of proper oral health care education programs continue to be made should be considered.

• 한국지역사회생활과학회지
• /
• 제20권2호
• /
• pp.157-168
• /
• 2009

This study was carried out to investigate the effect of eating behavior, physical status and tendency of eating disorder on the right eating habit. The subjects of this study were 324 middle school students and 340 high school students in Osan city GyeongGi province. The average of weight and height in the middle and high school students were 48.7kg, 160.0cm and 56.8kg, 164.8cm respectively. In PIBW values, 92.9% of middle school students and 99.1% of high school students were almost close to the average. The 28.5% of high school and 21.5% of middle school students were aware of themselves as overweight. The risk of eating disorders in high school students(16.4%) were higher than that in middle school students(4.9%). Moreover, the risk of eating disorders in girls high school students(19.3%) was significantly higher than those of middle school students(5.2%) (p<0.001). The thought of food problems were realized in 57.4% of in high school students and in 39.9% of in middle school students. The intake of food group frequency, middle school students ate more fruit than high school students(p<0.01). Boys ate more frequently soy beans (p<0.05) and algae(p<0.1) than girls in high school students. The meat intake was more frequent in high school students, but the eggs and milk were more in middle school students. The boys' intakes of fish and milk were more often than the girls' in high school students. Eating disorders and food intake frequency scores were closely correlated with weights(PIBW and the gap of ideal. weight with real weight). In conclusion, the education about realizing exact healthy body shape and how to modify behavior to prevent eating disorders should be planned since junior high school. Especially in high school girls, the variety food intake education would be needed. Proper recognition of the weight is required for good food intake and for prevent eating disorders.

• Corrosion Science and Technology
• /
• 제7권6호
• /
• pp.362-369
• /
• 2008

The impact abrasion behavior of high manganese steel is investigated under three kinds of impact energy in acid hematite ore slurry by using a modified MLD-10 impact abrasion tester. Through the SEM observation of the worn surface and the optical metallographic analysis of the cross-sectional samples, the corrosive impact abrasion mechanisms of the steel under different impact energies are studied. In acid-hematite slurry, the variations of impact energies would result in synchronous transformation of the impact abrasion properties and mechanisms of the high manganese steel in the corrosive condition, as led different corrosive impact abrasion mechanism under different impact energies.

• 수산해양교육연구
• /
• 제18권2호
• /
• pp.183-193
• /
• 2006

The aim of this research is to present the fundamental data of the tangible school operation in order to get Specialized High Schools in Computer fixed firmly and developed. This project was made by analyzing and thorough investigations how teachers and students think of their school lives, curriculum, future guidances, and the pursuing directions of the school. And that is based on understanding Specialized High Schools distinguished from the traditional Business High Schools. In order to develop the Specialized High School Related Computer as the model of the Specialized High School in Korea, it is important that the government trains the teachers who give students satisfactions. Also for the prospective future of the Specialized High School Related Computer, it is necessary that a good curriculum are developed in detail and the superior students are accepted in their entrance. Also, the students brought by the good teachers will contribute to Korean computer industries. So then, the Specialized High School Related Computer will be dispersed as training computer talents.

• 한국과학교육학회지
• /
• 제25권5호
• /
• pp.624-633
• /
• 2005

본 연구는 그래프 능력과 과학 탐구 능력 및 과학 학업 성취도의 상관 관계를 알아본 것이다. 그래프 능력과 과학 탐구 능력인 정적인 .41의 상관을 보였으며 이러한 결과는 선행연구의 결과들을 지지하는 것이다. 또한 그래프 능력은 과학 학업 성취도와 거의 통계적으로 상관이 없는 것으로 밝혀졌다. 그래프는 과학 학습에서 중요한 의사소통의 도구이다. 또한 그래프 능력은 과학 탐구 능력과 어느 정도 상관관계도 보이고 있다. 따라서 고등학생들의 그래프 능력의 부족한 부분을 신장시켜 과학 학습에 장애가 되지 않도록 해야 될 것이다.

• East Asian mathematical journal
• /
• 제31권4호
• /
• pp.483-503
• /
• 2015

While some studies have examined the concave and convex regular polygons respectively, very little work has been done to integrate and restructure polygon shapes. Therefore, this study aims to systematically reclassify the regular polygons on the through a comprehensive analysis of previous studies on the convex and concave regular polygons. For this study, the polygon's consistency with respect to the number of sides and angles was examined. Second, the consistency on the number of diagonals was also examined. Third, the size of the interior and exterior angels of regular polygons was investigated in order to discover the consistent properties. Fourth, the consistency concerning the area in regular polygons was inspected. Last, the consistency of the central figure number in the "k-th" regular polygons was examined. Given these examinations, this study suggests a way to create a concave regular polygon from a convex regular polygon.

• Journal of Communications and Networks
• /
• 제8권4호
• /
• pp.391-400
• /
• 2006

With the on-going wireless access technologies, the Internet has become accessible anytime anywhere. In wireless networks, link errors significantly degrade the performance of the transmission control protocol (TCP). To cope with this issue, this paper improves the recently-proposed terrestrial REFWA (T-REFWA) scheme by adding a new error recovery mechanism to its original design. In the T-REFWA scheme, senders are acknowledged with appropriate sending rates at which an efficient and fair utilization of network resources can be achieved. As the feedback values are computed independently of link errors, senders can keep transmitting data at high rates even in case of link error occurrences. Using this feature, the proposed error recovery mechanism can achieve high throughput in environments with high bit error rates. The throughput is further improved by disabling the exponential back-off algorithm of TCP so that long idle times are avoided in case of link errors. We show through simulations that the proposed method improves TCP performance in high bit error rates. Compared with several TCP variants, the proposed error recovery scheme exhibits higher link utilization and guarantees system fairness for different bit error rates.

• 대한화학회지
• /
• 제46권4호
• /
• pp.345-353
• /
• 2002

이 연구의 목적은 일반고와 과학고 학생들의 정신용량과 산화 환원 개녀 이해 정도가 산화 환원 반응식 완결 문제의 성취도에 미치는 영향을 분석하여 이러한 화학문제 해결에 대한 효과적인 학습 지도 방안 마련에 도움을 주고자 하는데 있다. 이를 위해 일반고 학생92명과 과학고 학생 57명을 연구대상으로 선정하여 정신용량검사, 산화 환원 개념 검사, 산화 환원 반응식 완결 검사를 실시하고 성취도를 미치는 영향을 분석하였다. 일반고 학생들은 정신용량이 클수록 산화 환원반응식 완결에서의 성취도가 증가하는 경향을 보였으나 과학고 학생들은 정신용량에 따른 성취도 차이가 없었다. 산화 환원개념 이해 정도를 분석한 결과, 일반고 학생들은 개념 이해 정독 전반적으로 매우 낮았으나 과학고 학생들은 비교적 높았다. 일반고 학생들은 개념을 부분적으로 이해한 학생들의 성취도는 개념을 이해하지 못한 학생들의 성취도보다 높게 나타났고 개념을 이해하지 못한 학생들은 정신용량이 클수록 성취도가 증가하였다. 과학고 학생들은 개념 이해 정도가 높을수록 성취도가 높게 나타났다. 산화 환원 개념을 완전하게 이해한 학생은 일반고와 과학고에 관계없이 그리고 문항 유형에 관계없이 높게 성취도를 나타냈음을 알 수 있었다