• Journal of Ocean Engineering and Technology
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• v.11 no.2
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• pp.131-137
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• 1997

The technology of small and medium sized shipbuilding companies is lower relatively to major shipbuilding companies, and should be up-graded from the viewpoint of national economic development. In spite that hul form design is one of the most important elements with respect to shipbuilding technology, small and medium sized shipbuilding companies are incapable of developing hull form. Inorder to support technically such companies hull form development was carried out for G/T 999ton class tanker and D/W 4990ton class tanker which are the typical vessels operating in coastal area. The operating efficiency for the developed hull forms are impeoved by 30% for G/T 999ton class tanker and 24% for D/W 4990 tonclass tanker respectively. The results of hull form development including ship model test and performance analysis are presented in this paper.

• Journal of the Korean Society of Marine Environment & Safety
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• v.3 no.1
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• pp.99-109
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• 1997

The in situ observations and the seawater analyses were conducted in July and August, 1996 for the purpose of describing the characteristics of organic pollution, dissolved oxygen distributions, and the evaluation of water quality in Mokpo harbour. The vertical density distribution of water column was found to be in stable structure with higher water temperature and lower salinity on surface layer at ebb tide in summer. In July, dissolved oxygen was shown to be oversaturated on surface and bottom layers, while in August, which was shown to be oversaturated on surface layer, and to be unsaturated on bottom layer as 68∼93% of saturation percentage. Dissolved oxygen of bottom layer in August was evaluated to be under the regular grades, based on Korean standards of seawater quality. In view of COD, the seawater quality of Mokpo harbour in summer was evaluated to be deteriorated due to organic wastes and graded to be the third class, and TSS of Mokpo harbour in summer was graded to be the second class, based on Korean standards of seawater quality. In particular, COD of surface layer in August was found to be under the regular grades. It is, therefore, necessary to take measures for the control of pollution loads and the proper management of seawater quality in Mokpo harbour. The distribution patterns of DO, COD, VSS and Chlorophyll-a on surface layer along the downstream center line from inner harbour to harbour entrance were similar to one another at ebb tide in August.

• Steel and Composite Structures
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• v.48 no.2
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• pp.191-206
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• 2023

The present research investigates how micromechanical models affect the behavior of Functionally Graded (FG) plates under different boundary conditions. The study employs diverse micromechanical models to assess the effective material properties of a two-phase particle composite featuring a volume fraction of particles that continuously varies throughout the thickness of the plate. Specifically, the research examines the vibrational response of the plate on a Winkler-Pasternak elastic foundation, considering different boundary conditions. To achieve this, the governing differential equations and boundary conditions are derived using Hamilton's principle, which is based on a four-variable shear deformation refined plate theory. Additionally, the Galerkin method is utilized to compute the plate's natural frequencies. The study explores how the plate's natural frequencies are influenced by various micromechanical models, such as Voigt, Reuss, Hashin-Shtrikman bounds, and Tamura, as well as factors such as boundary conditions, elastic foundation parameters, length-to-thickness ratio, and aspect ratio. The research results can provide valuable insights for future analyses of FG plates with different boundaries, utilizing different micromechanical models.

• Steel and Composite Structures
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• v.33 no.3
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• pp.403-432
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• 2019

Axially functionally graded (AFG) beams are a new class of composite structures that have continuous variations in material and/or geometrical parameters along the axial direction. In this study, the exact analytical solutions for the free vibration of AFG and uniform beams with general elastic supports are obtained by using Euler-Bernoulli beam theory. The elastic supports are modeled with linear rotational and lateral translational springs. Moreover, the material and/or geometrical properties of the AFG beams are assumed to vary continuously and together along the length of the beam according to the power-law forms. Accordingly, the accuracy, efficiency and capability of the proposed formulations are demonstrated by comparing the responses of the numerical examples with the available solutions. In the following, the effects of the elastic end restraints and AFG parameters, namely, gradient index and gradient coefficient, on the values of the first three natural frequencies of the AFG and uniform beams are investigated comprehensively. The analytical solutions are presented in tabular and graphical forms and can be used as the benchmark solutions. Furthermore, the results presented herein can be utilized for design of inhomogeneous beams with various supporting conditions.

• School Mathematics
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• v.5 no.4
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• pp.441-457
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• 2003

The purpose of this paper is to compare affective characteristics of mathematically gifted children and average students, by analying self-tests of self-efficacy and attitudes about mathematics. we survey 109 children from Mathematically Gifted Education Institutes located in Busan, and students from 6 elementary schools, each two graded A, B, and C, where schools graded A and B refer to so-called schools with concurrent and general classes and C schools with, semi-special and special classes ones. Those schools are determined through the consideration of geographical, cultural, and environmental conditions of 48 elementary schools under Seobu Educational Office, Busan Metropolitan City. From each of the six schools, a 5th-grade class is selected. That is, 205 students from 6 classes are finally selected. Results of the study can be described as follows. First, mathematically gifted children score higher on whole attitudes about mathematics and interest, preference, and confidence in each subarea than children from schools whose location is classified as A, B, and C. Irrespective of genders, mathematically gifted children are scored higher in the whole attitudes about mathematics than children from schools classified as A, B, and C. Second, mathematically gifted children are higher in score for self-efficacy than children from schools graded A, B, and C. Regardless of gender, mathematically gifted children are scored higher in self-efficacy than other groups of children. But mathematically gifted children's score is not significantly higher than that of children form schools graded A.

• Proceedings of the Korea Contents Association Conference
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• 2016.05a
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• pp.167-168
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• 2016

수업시간에 강의 듣고, 집에서 숙제를 하는 방식은 더 이상 학습자의 학습동기를 이끌지 못하고, 효과적인 수업이 이루어 질 수 없다. 수업시간에는 학생들의 적극적 상호작용이, 집에서는 인터넷 환경을 통한 핵심 강의식 내용을 미리 듣고 수업 활동에 임하는 플립러닝에 대한 영어과 수업의 도입이 필요하나 이에 대한 연구가 충분하지 않은 실정이다. 이에, 본 연구를 통해 영어수업(독해중심)에서의 플립러닝 활용 수업 모형을 개발하고, 이를 현장에 적용 후 수정 보완하여 대학 영어수업에서의 플립러닝 정착 및 발전을 도모한다.

• Imaging Science in Dentistry
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• v.46 no.3
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• pp.211-216
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• 2016

Purpose: The use of electronic tools in teaching is growing rapidly in all fields, and there are many options to choose from. We present one such platform, Learning Catalytics$^{TM}$ (LC) (Pearson, New York, NY, USA), which we utilized in our oral and maxillofacial radiology course for second-year dental students. Materials and Methods: The aim of our study was to assess the correlation between students' performance on course exams and self-assessment LC quizzes. The performance of 354 predoctoral dental students from 2 consecutive classes on the course exams and LC quizzes was assessed to identify correlations using the Spearman rank correlation test. The first class was given in-class LC quizzes that were graded for accuracy. The second class was given out-of-class quizzes that were treated as online self-assessment exercises. The grading in the self-assessment exercises was for participation only and not accuracy. All quizzes were scheduled 1-2 weeks before the course examinations. Results: A positive but weak correlation was found between the overall quiz scores and exam scores when the two classes were combined (P<0.0001). A positive but weak correlation was likewise found between students' performance on exams and on in-class LC quizzes (class of 2016) (P<0.0001) as well as on exams and online LC quizzes (class of 2017) (P<0.0001). Conclusion: It is not just the introduction of technological tools that impacts learning, but also their use in enabling an interactive learning environment. The LC platform provides an excellent technological tool for enhancing learning by improving bidirectional communication in a learning environment.

• The Journal of Korean Academic Society of Nursing Education
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• v.21 no.1
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• pp.141-149
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• 2015

Purpose: This study was carried out to describe the process and evaluation of a critical thinking class for new community health practitioners. Methods: The case study design was used to develop and evaluate a critical thinking class for 46 participants in the community health practitioners training program. The class was held two hours a week for 8 weeks. Critical thinking disposition was tested before and after the class and critical skill was graded according to the final test score. Data analysis was performed using descriptive statistics and paired t-tests using SPSS WIN 20.0. Results: Clinical critical thinking competences were identified through the literature review. The case situations with questions guiding the problem-solving process were developed and used for group discussion. Critical thinking disposition of participants was determined to have increased slightly after having taken the class. 17.4% of the participants had a competency level high enough to solve a problem and half of them stayed at the level of understanding of critical thinking. Compared with the class's satisfaction with the relevance to their jobs, the satisfaction with the learning method and instructor was high. Conclusion: The findings of this research will serve as the basis for developing critical thinking classes for community health nurses in order to improve their critical thinking competence.

• Fisheries and Aquatic Sciences
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• v.11 no.3
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• pp.125-132
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• 2008

The development of a fish that functionally provides both antioxidant and fat-reducing effects is an important goal in nutrition and aquaculture research. Dietary conjugated linoleic acid(CLA) can be successfully incorporated in fish muscle and viscera, but CLA and carotenoids have not been evaluated in such fish. An 8 weeks growth trial was conducted using rainbow trout, and all fish were fed twice daily with experimental diets containing graded amounts of CLA(1% and 5%). At the end of the experiment, the daily growth index, feed conversion rate, lipid class, and fatty acid composition were determined. Dietary CLA did not enhance the growth parameters of rainbow trout but did improve the feed conversion rate. The muscular polar lipid content decreased during the feeding period, while the content was stable in the viscera. In addition, a diet high in CLA decreased the polyunsaturated fatty acid content, but had no effect on the content of monounsaturated and saturated fatty acid in muscle.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.533-536
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• 2007

The LiDAR data structure has the potential for modeling in three dimensions because the LiDAR data can represent voxels with z value under certain defined conditions. Therefore, it is possible to classify the physical damaged degree of vegetation by forest fire as using the LiDAR data because the physical loss of canopy height and width by forest fire can be relative to an amount of points reached to the ground through the canopy of damaged forest. On the other hand, biological damage of vegetation by forest fire can be explained using the NDVI (Normalized Difference Vegetation Index) which show vegetation vitality. In this study, we graded the damaged degree of vegetation by forest fire in Yangyang-Gun of South Korea using the LiDAR data for physical grading and digital aerial photograph including Red, Green, Blue and Near Infra-Red bands for biological grading. The LiDAR data was classified into 2 classes, of which one was Serious Physical Damaged (SPD) and the other was Light Physical Damaged (LPD) area. The NDVI was also classified into 2 classes which are Serious Biological Damaged (SBD) and Light Biological Damaged (LBD) area respectively. With each 2 classes ofthe LiDAR data and NDVI, the damaged area by forest fire was graded into 4 degrees like damaged class 1,2,3 and 4 grade. As a result of this study, 1 graded area was the broadest and next was the 3 grade. With this result, we could know that the burned area by forest fire in Yangyang-Gun was damaged rather biologically because the NDVI in 1 and 3 grade appeared low value whereas the LiDAR data in 1 and 3 grade included light physical damage like the LPD.