• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.4
• /
• pp.380-388
• /
• 2023

This study estimates the metacentric height (GM) of a model ship by varying the transverse weight distribution, considering the effects of the roll period and moment of inertia, and compares it with the GM values measured by the inclining test. In the process, the relationship between the values is analyzed. Three types of ships-a 7-ton fishing vessel, 20-ton fishing vessel, and KRISO Very Large Crude-oil Carrier (KVLCC)-were used for the experiment and comparison. The roll period and moment of inertia were measured using the free roll decay and swing frame tests, and the GM was measured using inclining test. The estimated GM from the roll period and moment of inertia showed the same trend as the GM measured using the inclining test in the change of the weight distribution. However, the GM values measured using the inclining test were lower. Therefore, additional correction factors or parameters other than the roll period and moment of inertia are necessary for estimating GM. In the future, the relationship between the weight center and the estimated GM will be analyzed to derive the correction factors.

• Journal of The Korean Association For Science Education
• /
• v.19 no.3
• /
• pp.400-408
• /
• 1999

This study investigated the effect of the grouping method in cooperative learning applied to chemistry concept learning. Two grouping methods used were the HML (High-Medium-Low) and the HL/MM (High-Low/Medium-Medium) ability grouping. Three classes (N = 136) at a high school in Seoul were randomly assigned to the control and the treatment groups. Before instruction. the test of attitude toward science instruction, the perception questionnaire of learning environment consisting of three subtests (participation, conflict, and competition), and the questionnaire of self-esteem were administered, and a mid-term examination score was obtained. These scores were used as covariates. After instruction, the three tests administered before instruction and the conceptions test were administered. Two-way ANCOVA results revealed that there was a significant interaction between the treatment and the level of previous achievement. The low-level students in the HL/MM cooperative group performed better than those in the other groups. The cooperative groups, regardless of the grouping methods, exhibited more positive perception than the control group at participation subtest of the perception questionnaire of learning environment.

• Research in Mathematical Education
• /
• v.13 no.1
• /
• pp.5-12
• /
• 2009

Mathematical creativity is the most important factor for the advancement of mathematics. Only creative mind can produce creative results. But not much research work has been done in this direction. The present author has taken a scheme of developing a mathematical creativity test to identify creative children in mathematics and to find the relationships of psychoticism, neuroticism, intelligence, ability to achieve in mathematics and general creativity with mathematical creativity and their composite effect on it over a population of Bengali medium school students. In this approach, Bengali adaptation of English version of the "Verbal Test of Creative Thinking" by Mehdi [Mehdi, B. (1985). Manual of verbal test of creative thinking (revised edition). Agra, India: National Psychological Corporation.] has been completed. Works of adapting intelligence test, developing mathematical creativity test, adapting personality test in Bengali are in process. Relationships are to be found later.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.63 no.2
• /
• pp.119-123
• /
• 2014

In this study, four kinds of specimens of PE(polyethylene)-based insulating materials were prepared for selecting the optimum insulation materials in a wet environment. The specimens were tested by various methods, the anti tracking test, the transmittance test in the water vapor transmittance(WVT) and the abrasion resistive test, etc. The HDPE(high-density polyethylene) specimen was showed excellent property in the tracking resistance test and the lowest transmittance in water vapor transmittance test. In the abrasion resistive test, the LLDPE(linear low-density polyethylene) and MDPE(medium-density Polyethylene) were showed excellent mechanical properties. The value of cut-through resistance for MDPE and HDPE were superior to that for LLDPE and LDPE(low-density polyethylene).

• The Journal of Korean Academy of Prosthodontics
• /
• v.48 no.4
• /
• pp.259-265
• /
• 2010

Purpose: This study was aimed to evaluate the effect of different sizes of $\beta$-TCP/ HA particles on vertical bone augmentation using titanium mesh in the cranium of rabbits. Materials and methods: Six white rabbits weighing 5kg were used. Four circular grooves of 6mm diameter were made by trephine, and five small holes were drilled in the inner surface of each circular gooves. Different sizes of grafts (small 0.3 - 0.5 mm, medium 0.5 - 1.0, large 1.0 - 2.0 mm) were placed respectively in the experimental groups. Titanium mesh (height 3 mm, width 6 mm) was placed. After 8weeks healing period, the rabbits were euthanized, and the specimens were prepared for histological findings. New bone formation and remaining graft area were measured to calculate the ratio of areas occupying the inner space of titanium mesh. Mann-Whitney U-test and Wilcoxon signed rank-test were used for statistical analysis ($\alpha$ = .05). Results: The experimental groups with $\beta$-TCP/HA graft showed a significantly higher new bone formation (P = .003). Comparing different sizes of $\beta$-TCP/HA, there was no statistical difference in terms of new bone formation. The vertical bone formation (i.e. new bone and graft area) was significantly greater in $\beta$-TCP/HA groups (P = .001). In comparison between different sizes of $\beta$-TCP/HA, medium size group had significantly greater area than large particle size group (P = .039). Conclusion: The use of $\beta$-TCP/HA with titanium mesh showed a higher vertical bone formation, particularly the medium sized $\beta$-TCP/HA particles (0.5 - 1.0 mm) produced better results in vertical bone augmentation.

• Journal of The Korean Association For Science Education
• /
• v.18 no.1
• /
• pp.61-70
• /
• 1998

This study investigated the effects of grouping (group composition) in cooperative learning strategy upon students' achievement, the attitude toward science instruction, the perception of learning environment, and the self-esteem. Three different groups were used in this study. For the two treatment groups with cooperative learning strategies, High-Medium-Low ability grouping (HML) and High-Low I Medium-Medium ability grouping (HL/MM) were used. For the control group, traditional instruction was used. Before the instructions, the short-version Group Assessment of Logical Thinking, the test of attitudes toward science instruction, the perception questionnaire of learning environment, and the questionnaire of self-esteem were administered, and their scores were used as covariates. Mid-term examination score was used as a blocking variable. After the instructions, a researcher-made achievement test consisting of three subtests (knowledge, understanding, and application), the test of attitude toward science instruction, the perception questionnaire of learning environment, and the questionnaire of self-esteem were administered. The ANCOVA results revealed that there were significant interactions between the instruction and the level of prior achievement although there were no significant differences in all subtest scores of the achievement test. The high-level students in the HL/MM cooperative group performed better than those in the control group and the HML cooperative group. The low-level students in the HL/MM cooperative group also performed better in the subtest of knowledge than those in the other groups. However, the medium-level students in the HML cooperative group scored better than those in the control group and the HL/MM cooperative group. Significant main effect was also found in the perception of learning environment but not in the attitude toward science instruction and self-esteem. The cooperative groups, regardless of grouping, exhibited more positive perception than the control group.

• Korean Journal of Veterinary Research
• /
• v.41 no.2
• /
• pp.167-172
• /
• 2001

The present study was conducted to examine morphological and biological characteristics of 57 strains of Microsporum canis isolated from 110 dogs with dermatophytosis in Taegu, 1999. Isolated strains of M canis were classified into 4 types(A: white-yellow type, B: fluffy type, C: flat type, D: radial groove type) according to their pigmentation and morphology of colonies with typical conidia and hyphae. Some strains of A and B type happened variation by subculture for 6~8 months. The variation strains were classified into 3 types(E, F, G), E type had aberrant macroconidia with typical macroconidia, F type had aberrant hyphae(like dumb-bell) and macroconidia, and G type had no conidia and racket hyphae. All strains showed positive urease test, rice medium growth test and hair perforation test.

• Journal of Korean Academy of Nursing
• /
• v.50 no.6
• /
• pp.863-875
• /
• 2020

Purpose: This study was conducted to develop and test the effects of a program for practice application of intravenous infusion evidence based nursing practice (EBP) guidelines in small and medium-sized hospitals. Methods: A mixed method research design was used, combining non-equivalent control group pre-post test design with qualitative study analysis. The subjects consisted of 55 nurses. The practice application program was developed based on the Advancing Research and Clinical practice through close Collaboration (ARCC) model. Data were collected for analysis in the following areas: nurses' EBP organizational culture and readiness, EBP beliefs, EBP implementation, importance about intravenous infusion, and performance about intravenous infusion, with data assessed using valid and reliable instruments. Patient outcomes were collected from the hospital's medical records. Data were analyzed using t-test, χ2-test, and Shapiro-Wilk test, with qualitative content analysis used for interview data. Results: Following the intervention, nurses' EBP organizational culture and readiness, EBP beliefs, EBP implementation, and performance of intravenous infusion and perceptions of its importance showed significant improvement in the experimental group. Phlebitis rates decreased in the experimental group compared to the control group. Conclusion: This program is effective to improve nurse's perception and practice of evidence based nursing. Therefore we recommend to use this program at same levels of hospitals.

• Corrosion Science and Technology
• /
• v.21 no.3
• /
• pp.230-241
• /
• 2022

Austenitic stainless steel has been widely used because of its good corrosion resistance and mechanical properties. However, intergranular corrosion can occur if the alloy is welded or aged. The objective of this study was to determine intergranular corrosion behaviors of austenitic medium carbon (0.05 wt%) and low carbon (0.02 wt%) stainless steel aged at several conditions. Alloys were evaluated according to ASTM A262 Practice A, ISO 12732 DL-EPR (double loop-electrochemical potentiokinetic reactivation) test, and ASTM A262 Practice C. The degree of sensitization and intergranular corrosion rate were obtained. The relationship between the degree of sensitization and the intergranular corrosion rate showed a very large fluctuation. Such behavior might be related to whether two-dimension tests or three-dimension tests were performed. On the other hand, regardless of carbon content of alloys, when the intergranular corrosion rate increased, the degree of sensitization also increased. However, the DL-EPR test showed a higher sensitivity than the Huey test for differentiating the intergranular corrosion property at a low intergranular corrosion rate, while the Huey test had a higher sensitivity than the DL-EPR test for distinguishing the intergranular corrosion property at a high intergranular corrosion rate.

• Journal of Korea Technology Innovation Society
• /
• v.20 no.3
• /
• pp.546-575
• /
• 2017

This paper investigates the effects of public R&D support on medium-sized firms' R&D investment. The paper collects a panel dataset of Korean manufacturing firms' R&D investment and public support, and employs the DID (difference-in-differences) regression for the test of stimulating or crowding-out effect. Empirical analysis examines how the effect of public R&D support differs between small and medium-sized firms and whether firm size and technological capability moderate the effect in the sample of medium-sized firms. Empirical results show that public R&D support tends to generally stimulate private pure R&D investment for both small and medium-sized firms. Comparing the results for small and medium-sized firms, this paper finds that the stimulating effect is relatively larger and more significant for medium-sized firms, while the effect is not significant for small ones. Furthermore, the paper shows that the stimulating effect of public R&D subsidy on private R&D investment is relatively stronger for medium-sized firms with superior technological competence and the effect of tax support is greater for incompetent firms. These results suggest that public R&D policies and R&D programs, differentiated from those for existing small firms, are necessary for medium-sized firms to stimulate private R&D continuously and formulated carefully by considering firm size, technological capability and growth potential.