• Journal of Educational Research in Mathematics
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• v.16 no.1
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• pp.25-41
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• 2006

The purpose of this study was to analyze teachers' pedagogical content knowledge (PCK) about area of plane figure and how it was actualized in instruction. As an exploratory, qualitative, and comparative case study, 2 fifth-grade teachers were selected. Semi-structured interviews with the leachers were conducted in order to explore their PCK with regard to the area of plane figure. A total of 14 mathematics instructions were videotaped and transcribed. Teachers' PCK and classroom teaching practices were analyzed in detail into 3 categories: (a) knowledge of mathematics contents, (b) knowledge of students' understanding, and (c) knowledge of instructional methods. As such, this paper provided a detailed description on each teacher's PCK and her teaching practice. The results showed that teachers' PCK had a significant impact on instruction. The teacher who had rich knowledge about the area of plane figure was able to encourage students to understand the concept of area and to or explore the principles behind formula calculating various areas of plane geometry. The results demonstrated the importance of individual components of PCK as well as that of overall level of PCK. Different aspects of teaching practices were observed as to how the teachers had internalized PCK. On the basis of a close relationship between teachers' PCK and their teaching practice, this paper finally raised several implications for teachers' professional development for effective mathematics instruction.

• Journal of Biomedical Engineering Research
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• v.22 no.5
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• pp.449-458
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• 2001

This is a test report of system efficiency for the moving-actuator type Bi-ventricular assist device (AnyHear $t^{MT}$ ) Seoul National University). $AnyHeart^{TM}$), as an energy converter. utilities a brushless DC motor(S/M 566-26A. Sierracin/ Magnedyne, Carlsbad, CA. U.S.A.) generating their pendulous motion in the epicyclic gear train. It is necessary to know about the overall efficiency of the system. The system is subdivided into three parts: motor part, actuator part and blood sac part (including valves, etc.) according to system mechanism. The motor was operated with a variable range of torque. angular speed and width of voltage Pulse In this report. $AnyHeart^{TM}$ is focused on the efficiency of the motor and actuator parts. 4 $\ell/min$ pump output. which is normal condition of $AnyHeart^{TM}$ system, the total system efficiency is 8%, which is composed of 50%, 85% and 17% efficiency (motor Part, actuator Part and blood sac Part) respectively. In the analyzed result. applied input voltage on normal condition of $AnyHeart^{TM}$ is determined. Also speed Profile with considering filling state of blood sac is Provided. In the test of the in vitro mock circulation. some experimental results are Provided to demonstrate the effectiveness of the Presented approach.

• Applied Biological Chemistry
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• v.36 no.5
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• pp.346-351
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• 1993

In present paper, we examined the quality stability of vinegar pickled sardine during storage. The moisture content of all samples showed a little change, while pH and volatile basic nitrogen content of pickled sardine processed with vinegar seasoning solution mixed antioxidants increased during storage at ambient temperature. The viable cell counts and histamine content of vinegar pickled sardine increased very standingly during storage at ambient temperature, while increased vely slowly during cold storage. The thiobarbituric acid value and peroxide value of vinegar pickled sardine prepared without antioxidants increased up to 60 days and then decreased during cold storage. In case of changes in fatty acid composition of vinegar pickled sardine prepared without antioxidants during cold, percentage of polyenes such as 20 : 5 and 22 : 6 decreased. In case of the results for texture profile analysis of vinegar pickled sardine treated with antioxidants during storage at ambient temperature, the hardness and toughness decreased, while the cohesiveness and elasticity showed a little changes. Judging from the results of chemical and sensory evaluation, the product B, sardine pickled in vinegar seasoning solution mixed with antioxidants could be keeped on freshness and retarded on lipid oxidation until 90 days during storage at $5^{\circ}C$.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.2
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• pp.125-133
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• 2014

The purpose of this study was to investigate the effect of various surface treatment methods on the shear bond strength of orthodontic brackets in vitro. Ninety six specimens, 6 mm in diameter and 5 mm in height, were made with composite resin ($Filtek^{TM}$ Z350 XT, 3M ESPE, USA) and treated with an aging procedure. After aging, the specimens were randomly separated in six groups: (1) control with no surface treatment, (2) 37% phosphoric acid gel, (3) 4% hydrofluoric acid gel, (4) sodium bicarbonate particle abrasion, (5) diamond bur, and (6) 1 W carbon dioxide laser for 5s. The metal brackets were bonded to composite surfaces by means of an orthodontic adhesive (Transbond XT, 3M Unitek, USA). Shear bond strength values were evaluated with a universal testing machine (R&B Inc., Korea). Analysis of variance showed a significant difference between the groups. Group 5 had the highest mean shear bond strength (11.9 MPa), followed by group 6 (11.1 MPa). Among the experimental groups, group 2 resulted in the weakest mean shear bond strength (5.22 MPa). The results of this study suggest that the repair shear bond strength of the aged composite resin was acceptable by surface treatment with a carbon dioxide laser.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.2 no.1
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• pp.132-177
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• 1974

Toe public library may perform a social good only when its objectives are adequate to the community's needs. The present purpose of the public library in the Korean Library Act has no direct concern for our social needs from its very beginning because it was not created in response to our social needs but transplanted from American principles. It is, therefore. difficult to expect socially useful output of our public library programs under the present purpose which may be inadequate to our social tradition and needs. This study purposes to examine validity of the present purpose of the public library in the Korean Library Act, in the light of our community needs and our own library tradition. The methods employed to achieve the purpose of the study are (1) to survey needs of the library frequenters through questionnaire, and interviews with the public librarians in Seoul, (2) to gather the statistical data relevant to, and supporting, the hypothesis, and (3) to compare our social background with that of the United States of which the American purpose, a model for our present purpose, came out. The conclusion is as follows: A. The idea to induce people to pull themselves upward by providing for all the members of the community access to the world's best books shelved in the public library should be abandoned. The reasons are (1) that the idea is alien in our public library tradition, (2) that little demand of the community goes with the idea, and (3) that reading outside the library has come into wide practice, thanks to recent increase in individual income and that in publications. B. That the public library maintains fiction and other recreational reading materials is meaningless in the light of the community needs. These are the two explanations supporting the thesis. (1) The "uplift" theory has proved inoperative and people apparently do not progress from, light fiction to more respectable fare. (2) The conviction that fiction and other recreational reading materials keep the middling classes from the "vicious" entertainments maintaining order in the community by giving them a harmless source of recreation has lost its significance as the modern society provides a number of choices in recreation: television is an obvious example. C. The nature of the informational needs of the community has radically changed, so radically as to require substantial changes in the outlook, collections, and services of the public library, which is :slow in adopting itself to the new social surroundings in Korea. D. 92.2 per Cent of the present frequenters of the public library are high school and college students. Since the library is to meet the existing community needs it should turn its attention to the student group, and develop the means to serve it better, not the "theoretical group of specialists who do not come to "the public library. E. In revision of the purpose of the public library, priority of each objective should be given. The priorities in the last analysis are research and information. culture, recreation in that order.

• Journal of Environmental Policy
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• v.12 no.4
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• pp.71-92
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• 2013

Unlike general public investment projects, when it comes to environmental public investment projects, there is a gap between those who pay the costs, and those who receive the benefits. This is because of the long term nature of environmental investments, which entails that the majority of the costs are paid by the current generation, while the benefits are reaped by future generations. Because of this, when the social discount rate is set at a standard, singular rate, an issue of relative underestimation of the benefits reaped by future generations may occur during the analytic process. This paper begins with the recognition of this problem, and attempts to estimate a suitable social discount rate that can be applied to environmental investment projects. Taking into account recent economic situations, the social discount rate is currently being estimated at between 2.9 ~ 4.9%. Also, this paper used preliminary feasibility studies that took place so far, to analyze the standard pattern of benefit generation. This revealed that alterations in social discount rates can bring significant changes in economic feasibility test results. Simulation results showed that roughly 6% of B/C ratios could be increased by 1%p. resulting in a decrease in social discount rates. Also if we use hyperbolic discount rates, instead of using the current singular rate, there would be a meaningful increase in the benefits for the future generation.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.3
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• pp.303-310
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• 2015

The study was conducted to analyze the genetic parameters of somatic cell score (SCS) of Holstein cows, which is an important indicator to udder health. Test-day records of somatic cell counts (SCC) of 305-day lactation design from first to fifth lactations were collected on Holsteins in Korea during 2000 to 2012. Records of animals within 18 to 42 months, 30 to 54 months, 42 to 66 months, 54 to 78 months, and 66 to 90 months of age at the first, second, third, fourth and fifth parities were analyzed, respectively. Somatic cell scores were calculated, and adjusted for lactation production stages by Wilmink's function. Lactation averages of SCS ($LSCS_1$ through $LSCS_5$) were derived by further adjustments of each test-day SCS for five age groups in particular lactations. Two datasets were prepared through restrictions on number of sires/herd and dams/herd, progenies/sire, and number of parities/cow to reduce data size and attain better relationships among animals. All LSCS traits were treated as individual trait and, analyzed through multiple-trait sire models and single trait animal models via VCE 6.0 software package. Herd-year was fitted as a random effect. Age at calving was regressed as a fixed covariate. The mean LSCS of five lactations were between 3.507 and 4.322 that corresponded to a SCC range between 71,000 and 125,000 cells/mL; with coefficient of variation from 28.2% to 29.9%. Heritability estimates from sire models were within the range of 0.10 to 0.16 for all LSCS. Heritability was the highest at lactation 2 from both datasets (0.14/0.16) and lowest at lactation 5 (0.11/0.10) using sire model. Heritabilities from single trait animal model analyses were slightly higher than sire models. Genetic correlations between LSCS traits were strong (0.62 to 0.99). Very strong associations (0.96 to 0.99) were present between successive records of later lactations. Phenotypic correlations were relatively weaker (<0.55). All correlations became weaker at distant lactations. The estimated breeding values (EBVs) of LSCS traits were somewhat similar over the years for a particular lactation, but increased with lactation number increment. The lowest EBV in first lactation indicated that selection for SCS (mastitis resistance) might be better with later lactation records. It is expected that results obtained from these multi-trait lactation model analyses, being the first large scale SCS data analysis in Korea, would create a good starting step for application of advanced statistical tools for future genomic studies focusing on selection for mastitis resistance in Holsteins of Korea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.11
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• pp.1821-1828
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• 2013

This study was conducted to investigate the physicochemical and microbial properties of Makgeolli supplemented with kiwifruit (Actinidia deliciosa). Four hundred grams of kiwifruit were added to 3.1 L of distilled water, followed by 2.0 kg of rice, 40.0 g of Nuruk, and 14.0 g of yeast. The mixed rice solution was then fermented at $28^{\circ}C$ for 6 days to prepare the kiwifruit Makgeolli. The pH values of the kiwifruit Makgeolli decreased from 5.31 to 4.37, but the total acidity values increased from 0.05 to 0.34% during fermentation. The total viable cells ($3.18{\times}10^7$ and $2.88{\times}10^7$, respectively), lactic acid bacteria ($1.51{\times}10^6$ and $1.50{\times}10^6$, respectively), and yeast counts ($1.96{\times}10^7$ and $1.90{\times}10^7$, respectively) of the kiwifruit Makgeolli and control were similar throughout the fermentation process. Glucose was the major free sugar in the control and kiwifruit Makgeolli and significantly decreased during fermentation. Succinic acid was the highest organic acid in both the control (24.6 mg/mL) and kiwifruit Makgeolli (26.3 mg/mL). In a volatile compound analysis, 3-methyl-1-butanol, 2-methyl-1-propanol and ethyl acetate were the major volatile compounds in the kiwifruit Makgeolli.

• Korean Journal of Community Nutrition
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• v.10 no.1
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• pp.101-110
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• 2005

This survey was carried out to obtain the information concerning nutritional status, including factors of food habits and nutrient intake of the long-lived elderly men and women living in Ganghwa-gun. In order to assess the quality of dietary intake among the elderly, a survey was conducted during December 2003 of 103 subjects who were over 85 years of age. Dietary nutrient intake data were obtained through the 24 hr recall method. Chi-square test and t-test were the main data analysis method. Their dietary habits such as three meals a day and a regular meal time have shown that they have generally good eating habits. Average daily calorie intake ($\%$ RDA) was 1233.2 kcal ($68.8\%$) for male and 1215.8 kcal ($75.8\%$) for female which were lower than the Recommended Dietary Allowances (RDA) for Koreans. Energy intake of females got closer to RDA than that of male. Protein intake was 49.3 g for male and 46.9 g for female (which was $82.3\%$ RDA for male and $85.1\%$ RDA for female) for elderly person, the proportion of animal protein to total protein intake were $45.2\%$ for male and $39.0\%$ for female. Average CPF ratio of energy intake for both male and female were 68.7 : 16.1 : 15.2 and 69.6 : 15.4 : 15.0. SFA : MUFA : PUFA ratio of the subject was 0.78 : 1.03 : 1.00 for male and 0.64 : 0.92 : 1.00 for female. Calcium intakes for both males and females were 321.3 mg and 377.2 mg. Vitamin A was the nutrient found to be least sufficient. Mean daily intakes of most of the vitamins and minerals for both males and females were lower than RDA except vitamin C and Zn for female, especially $\%$ RDAs of vitamin A, Ca for male and vitamin A for females were less than $50\%$ of RDA. In conclusion, long-lived elderly in Ganghwa areas did not consume enough nutrients quantitatively as well as qualitatively, especially Ca, Fe, vitamin A, vitamin $B_2$ and vitamin E. These results suggest that nutritional guidelines for older Koreans should focus on the maintenance of adequate energy intake. In addition, selection of foods with high protein and calcium, such as dairy food, should be emphasized, particularly in the long-lived elderly.

• Investigative Magnetic Resonance Imaging
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• v.11 no.2
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• pp.95-102
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• 2007

Purpose: To acquire high-resolution spiral-scan images at higher magnetic field, high homogeneous magnetic field is needed. Field inhomogeneity mapping and in-vivo shimming are important for rapid imaging such as spiral-scan imaging. The rapid scanning sequences are very susceptible to inhomogeneity. In this paper, we proposed a higher-order shimming method to obtain homogeneous magnetic field. Materials and Methods: To reduce measurement time for field inhomogeneity mapping, simultaneous axial/ sagittal, and coronal acquisitions are done using multi-slice based Fast Spin echo sequence. Acquired field inhomogeneity map is analyzed using the spherical harmonic functions, and shim currents are obtained by the multiplication of the pseudo-inverse of the field pattern with the inhomogeneity map. Results: Since the field inhomogeneity is increasing in proportion to the magnetic field, higher order shimming to reduce the inhomogeneity becomes more important in high field imaging. The shimming technique in which axial, sagittal, and coronal section inhomogeneity maps are obtained in one scan is developed, and the shimming method based on the analysis of spherical harmonics of the imhomogenity map is applied. The proposed technique is applicable to a localized shimming as well. High resolution spiral-scan imaging was successfully obtained with the proposed higher order shimming. Conclusion: Proposed pulse sequence for rapid measurement of inhomogeneity map and higher order shimming based on the inhomogeneity map work very well at 3 Tesla MRI system. With the proposed higher order shimming and localized higher order shimming techniques, high resolution spiral-scan images are successfully obtained at 3 T MRI system.