• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.2
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• pp.137-144
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• 2009

In this paper, the signal analysis of eddy current array probe was performed to analyze the electromagnetic characteristics with the variation of FBH(flat bottomed hole) defects size on steam generator tube in NPP(nuclear power plants) using the electromagnetic finite element method. To obtain the electromagnetic characteristic of probes, the governing equation was derived from Maxwell's equations, and the individual problem was analyzed by using the 3-dimensional finite element method. For the simulation FBH defects were used. The depth of FBH defects were 20%, 40%, 60%, 80% and 100% of steam generator(SG) tube thickness, and it was assumed that the defects were located on the tube outside. And the operation frequencies of 100 kHz, 300 kHz and 400 kHz were used. Material of specimen was Inconel 600 which is usually used for SG tubes in NPP. The signal difference could be observed according to the size variation of depth of FBH defects and operation frequencies. The results in this paper can be helpful when the ECT(eddy current testing) signals from EC array probe are evaluated and analyzed.

• Journal of the Korean Society for Library and Information Science
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• v.47 no.3
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• pp.407-435
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• 2013

The purpose of this study is to have the development of special libraries in Korea and produce policy alternatives and current implications as well as to analyze the management evaluation of Korea special libraries in 2011. The evaluation of 39 detailed index scored at 51.8 out of 100. There were five evaluation territory. Among them, the facility environment's score was the highest as 77.3 and manpower was 53.5, library management were 51.0. The information resource and service territory were analyzed under 50 as scored 49.3 and 45.4. Closely look at the detailed index, the highest index was 'user amenity' (96.7) from facility environment and the lowest index was 'participation record of the long-term educational training of library staff' (13.0). This study diagnosed current management of libraries and problem as well as to analyze the result of administration evaluations of special libraries in nation throughout 2012. The institution type of special libraries in Korea is very varied such as central administrative agency, government-funded research institute, local government, and education office in local-affiliated institute, business, private organization, hospital, the press and so on; therefore, the analysis result can be utilize for basic information to provide future special libraries type in order to make differentiated policy making.

• Economic and Environmental Geology
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• v.14 no.3
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• pp.111-122
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• 1981

This study is a model analysis for an effective application of the geophysical prospecting to the investigation of geological structures or useful resources, and the purpose of it is to research a property of the electrical resistivity prospecting, especially by using a Three-Point electrode array method. In using the Three-Point electrode array method, it is theoretically assumed to choose the infinite for a distance between the two current electrodes, however it is impossible in applying to the practical field prospecting. Therefore this study was conducted for determination and presentation of a minimum appropriate distance between the two current electrodes by making a study on prospecting effect in the variation of distance between both the electrodes. In case that the ratios of the distance between the two current electrodes to that between the two potential electrodes are respectively chosen for 40, 400, 5,000, the experimental data of this study showed that the minimum appropriate distance between the two current electrodes is forty times as much as that between two potential electrodes. In order to make clear a problem about prospecting depth which is essential to the data processing, it had been chosen equally to the distance between two potential electrodes. As a result of it, it was shown that the anomaly is appeared along the position of an assumed ore body. Consequently it was found out that the prospecting depth of the Three-Point electrode array method is the same as the distance between the two potential electrodes. From the model experiment on the sheeting ore body(or linear structure) of horizontal, dipping of $30^{\circ}$, $60^{\circ}$ and vertical on the basis of above experimental condition, it was found out that the position and dip of assumed ore body could be inferred from the aspects of the equiresistivity curve. In consequence of performing out the simultaneous Normal and Reversal electrode movement, it was shown that the electrode movement of the Reversal forms the anomaly more clearly than that of Normal when the sheeting ore body is situated obliquely, therefore it could be ascertained that the electrode movement have to be performed simultaneously in the manner of Normal and Reversal. It was also exhibited that the aspect of the equiresistivity curve forms symmetrically when an assumed ore body (or linear structure) is situated horizontally or vertically, that is, symmetrically, and moreover that the aspect of the equiresistivity curve forms unsymmetrically when an assumed ore body (or linear structure) is situated obliquely. On the basis of these experimental analysis it is thought that it can be inferred from the aspect of equiresistivity curve whether an assumed ore body is obliquely situated or not.

• Journal of Korean society of Dental Hygiene
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• v.10 no.2
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• pp.255-268
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• 2010

Objectives : In the field of dental hygiene, infections pose a serious problem. This issue has left many patients and dental staff exposed to microbes with potentially far-reaching effects. The purpose of this study was to find solutions which could improve Dental health policies and promote improved methods for the control of infections. This survey was conducted between March 3, 2008 and March 30, 2008, in the metropolitan area. The research was carried out in dental clinics and dental hygienists were surveyed through a questionnaire. Methods : Collected data was examined using the SPSS 14.0 program, using frequency, mean and standard deviation analysis, T-test, one-way ANOVA, Scheffe's test and Duncan's test. Further analysis was given using Logistic Regression. Results : The Performance of Infection Control by dental hygienists in Dental Clinics was shown at $2.96{\pm}0.42$. Disinfection, sterilization and the wearing of masks is high at $3.65{\pm}0.64$, $3.64{\pm}0.65$. The perception of the importance of infection control is higher among dental hygienists than dentists. Of the dental hygienists surveyed, 83.9% were exposed to at least one accident while at work. Age and years of experience were important in relation to infection control practices. The rate of infections and the number of accidents experienced related to the dental hygienists performance of infection control. The performance of infection control is influenced by the dental hygienists own perceptions, and the perceptions of their dentists. The dental hygienist's working conditions and their beliefs related to infection control were shown to influence their performance of infection control practices. Conclusion : At the conclusion of this investigation, it was determined that systematic refresher training of infection control should be delivered through further education and various media. Dental health care workers should be encouraged to practice these action items presented in the training. For successful implementation of infection control in every dental health-care setting, it is highly demanded that effective safe-guard tools, strategic support and standardized action items against infection problems are developed.

• The Journal of the Korea Contents Association
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• v.17 no.10
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• pp.307-321
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• 2017

This study examined the developmental changes of adolescent personality regarding personality traits of Big 5 model in 2,260 middle and high school students. We found that there was a difference in the developmental change of personality 5 factor according to sex and grade. In addition, we investigated the timing and characteristics of adolescent problem behavior by analyzing the sub - factors of neurosis. Analysis was used for One-Way ANOVA. if there is significant differences we proceeded post hoc tests. The results of this study are as follows; first, The five personality traits of the adolescents showed differences according to gender. The girls were higher than boys in the Openness, Conscientiousness and Extraversion. In contrast, the boys were higher than girls in the Neuroticism. Second, There was a difference in the characteristics of five personality traits of adolescents according to grade. Third, Gender-specific developmental grade tendency characteristics of adolescent personality trait shows a different pattern in gender. Especially, in the analysis by gender and grade boys showed that personality traits prominent in the middle school Grade 2. likewise, girls showed that personality traits prominent in the high school Grade 3. Then, associated with Neuroticism the Externalizing behavior problems was found to be expressed in the middle school Grade 1 and 2. likewise, the Internalizing behavior problems was found to be expressed in high school Grade 3. Therefore, this study was able to determine the current developmental change in personality traits adolescence of our country. Also it found that mental health problems can be a different expression depending on gender and grade.

• Analytical Science and Technology
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• v.18 no.1
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• pp.5-12
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• 2005

It has been established that soft error of high precision electronic circuits can be induced by alpha particles emitted from the naturally occurring radioactive impurities such as U, and Th. As the electronic circuits have recently become lower dimension and higher density, these alpha-particle emitting radioactive impurities have to be strictly controlled. The aim of this study is to develop of NAA (Neutron Activation Analysis) and gamma-spectrometry to improve the analytical sensitivity and precision of U and Th. A new NAA method has been established using the HTS (Hydrulic transfer system) irradiation facility which has been used to produce radioisotopes for industries and medicines instead of the PTS (pneumatic transfer system) irradiation facility which has been used in general NAA. When the ultratrace impurities have to be analyzed by NAA, background gamma-ray spectra induced from $^{222}Rn$ and its progenies in air is serious problem. This unstable background has been eliminated or stabilized by the use of a nitrogen purging system. Ultra trace amounts of U (0.1 ng/g) and Th (0.01 ng/g) in high purity silica used for EMC could be analyzed by the use of HTS-NAA and low background gamma-spectrometry.

• Journal of Animal Science and Technology
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• v.48 no.6
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• pp.759-766
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• 2006

This study was conducted to investigate the genetic correlations among the traits used to select young bulls and proven bulls in Hanwoo Performance and Progeny Test Program in Korea. For the estimation of heritabilities and correlations among the growth traits of bulls and carcass traits of progeny steers, 2,532 records of performance tested bull calves and 1,819 records of progeny tested steers were collected from Livestock Improvement Main Center (LIMC), National Agricultural Cooperative Federation (NACF). Fixed effects of mixed model for each traits were selected by using stepwise regression analysis and prior values of variance components were estimated by MTDFREML. The prior values of variance components were estimated with pairwise 2 traits model followed by single trait analysis. The estimated heritability of backfat thickness(BF), dressing percentage(DP), loin-eye muscle area(LMA), marbling score(MS) and weight at 12 months(WT12) was 0.51, 0.32, 0.27, 0.33, 0.50 and 0.26, respectively. Genetic correlation of WT12 of bull calves with backfat thickness, carcass weight and loin-eye muscle area of steers was positive correlation as 0.05, 0.35 and 0.21, respectively. However genetic correlation of WT12 with DP and MS showed negative correlation as 󰠏0.09 and 󰠏0.27, respectively and these negative genetic correlations implies that bulls that may be superior in carcass traits can be lost at the first step of selection and current selection method should be modified to solve this problem.

• Journal of Elementary Mathematics Education in Korea
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• v.9 no.1
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• pp.65-84
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• 2005

The purpose of this study was to analyze the contents and designs of the developed 22 teaching and programs for the gifted students in elementary mathematics. The focus of the analysis were the participants and the characteristics of the contents, and were to reflect them on the areas of the 7th elementary mathematics curriculum and Renzulli's Enrichment Triad Model. The results of the study as follows: First, the programs for the low grade gifted students are very few compared to those of the high grade students. For earlier development of the young gifted students, we need to develop more programs for the young gifted students. Second, there are many programs in the area of geometry, whereas few programs are developed in the area of measurement. We need to develop programs in the various areas such as measurement, probability and statistics, and patterns and representations. Third, most programs do not follow the steps of the Renzulli's Enrichment Triad Model, and the frequency of appearance of the steps are the 1st, 2nd, and 3rd enrichments, sequentially. We need to develop hierarchical programs in which the sequency and relations are well orchestrated. Fourth, the frequency of appearance is as follows as sequentially: types of exploration of topics, creative problem solving, using materials, project types, and types of games and puzzles. In the development of structure of the program, the following factors should be considered: name of the chapter, overview of the chapter, objectives, contents by steps, evaluation, reading materials, and extra materials.

• The Journal of the Korea Contents Association
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• v.17 no.7
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• pp.113-123
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• 2017

This research is designed to review the systems thinking and STEAM theory while ascertaining the effects of the classroom application of the STEAM programs based on systems thinking appropriate for studying climate change. The systems thinking based STEAM program has been developed by researchers and experts, who had participated in expert meetings in a continued manner. The program was applied to science classes over the course of eight weeks. Therefore, the application effects of the systems thinking based STEAM program were analyzed in students' systems thinking, STEAM semantics survey, and students' academic achievement. The findings are as follows. First, the test group has shown a statistically meaningful difference in the systems thinking analysis compared to the control group in the four subcategories of 'Systems Analysis', 'Personal Mastery', 'Shared Vision' and 'Team Learning' except for 'Mental Model'. Second, in the pre- and post-knowledge tests, the independent sample t-test results in the areas of science, technology, engineering, art and mathematics show statistically meaningful differences compared to the control group. Third, in the academic performance test regarding climate change, the test group displayed higher achievement than the control group. In conclusion, the system-based STEAM program is considered appropriate to enhance amalgamative thinking skills based on systems thinking. In addition, the program is expected to improve creative thinking and problem-solving abilities by offering new ideas based on climate change science.

• School Mathematics
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• v.15 no.4
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• pp.759-783
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• 2013

Both curriculum and textbooks play an important role in the process of didactical transposition from mathematics as a science to school mathematics. The 2009 revised national curriculum for mathematics introduced the system of grade-band, so its achievement criteria for mathematical contents tend to be addressed more and less generally in the curriculum. We need to investigate whether the achievement criteria were applied meaningfully in elementary textbooks for mathematics. This study aims to recognize the connection between the curriculum and the textbooks and make a suggestion for composing the following curriculum and its textbooks. To do this, we analyzed the mathematics textbooks for 1~2 grades in relation to the mathematical contents as per reconstructed one of curriculum achievement criteria, the mathematical terms and symbols, and the mathematical processes -mathematical problem solving, mathematical reasoning, mathematical communication. Based this analysis, futhermore, this study includes some didactical discussions and implications for development of mathematics textbooks in 3~4 and 5~6 grade-bands.