• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.116-124
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• 2006

A model test was carried out, in order to verify the hydrodynamic performances of public 30 feet class sailing yacht. In the initial design stage, the performances and the running attitude of sail yacht including the hull form and sail plan, appendages were estimated by VPP, from which made the representative test conditions. A new experiment system such as captive model device was composed because the running attitude could be changed by wind conditions. The test results show that the minimum resistance is generated in the heeling 20 degree. which was expected in the initial design stage. It is thought to be the useful informations that the keel has an effects on hydrodynamic forces and resistance differences between the upwind and the downwind condition. Also this paper is associated with the state-of-the-art of calculating sailing yacht performance as this is performed in velocity Prediction program (VPP) The VPP results shows a typical shape of a sailing yacht and the designed yacht has the best performance at 120 degree angle of true wind with 20 knots.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.824-831
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• 2005

A model test was carried out, in order to verify the hydrodynamic performances of public 30 feet class sailing yacht. In the initial design stage, the performances and the running attitude of sail yacht including the hull form and sail plan, appendages were estimated by VPP, from which made the representative test conditions. A new experiment system such as captive model device was composed because the running attitude could be changed by wind conditions. The test results show that the minimum resistance is generated in the heeling 20 degree, which was expected in the initial design stage. It is thought to be the useful informations that the keel has an effects on hydrodynamic forces and resistance differences between the upwind and the downwind condition. Also this paper is associated with the state-of-the-art of calculating sailing yacht performance as this is performed in velocity prediction program (VPP). The VPP results shows a typical shape of a sailing yacht and the designed yacht has the best performance at 120 degree angle of true wind with 20 knots.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.4
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• pp.298-304
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• 2003

In this paper a free-form hull design program and performance prediction program for planing boat is introduced. This program enables the designer to do complex geometric hull shape design on a personal computer and accurately to predict power requirements for a given loading and velocity. For a free form design, Bezier curve model is adopted as a basic representation tool of curves and surfaces, and this program has versatile functions to do fairing jobs with a convenient graphical user interface. After creating a hull form the geometric data is provided in a manner compatible with a variety of analysis tools including 'Motion Analysis(by Zarnick)' for prediction of motion characteristics in regular waves, 'Running Attitude (by Savitsky)' for prediction of the running attitude and required power.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.3
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• pp.233-240
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• 2005

A model test was carried out, in order to verify the hydrodynamic performances of public 30 feet class sailing yacht. In the initial design stage, the performances and the running attitude of sail yacht including the hull form and sail plan, appendages were estimated by VPP, from which made the representative test conditions. A new experiment system such as captive model device was composed because the running attitude could be changed by wind conditions. The test results show that the minimum resistance is generated in the heeling 20 degree, which was expected in the initial design stage. It is thought to be the useful informations that the keel has au effects on hydrodynamic forces and resistance differences between the upwind and the downwind condition.

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.123-123
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• 2017

• Journal of Korean Elementary Science Education
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• v.18 no.2
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• pp.79-101
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• 1999

Astronomy is a good area to introduce a student to the study of science. The student often questions what causes the change in seasons, in the day and right, and in the rotation of stars, etc. Attempts to find answers to problems related to these astronomical observations influence the student`s intellectual development. This study is to investigate the effect of running an astronomical observations program on the preservice elementary teachers' astronomy achievement, astronomy teaching efficacy beliefs, and scientific attitude. Students consist of twenty four preservice elementary teachers. Three instruments are used: one is the astronomy achievement test, which is of an essay type, and 5 items. The other is the astronomy teaching efficacy beliefs test, which is of a Likert scale type, and 22 items. Another is the scientific attitude test, which is of the Likert scale type, and 10 items. Data are collected before and after instruction in the astronomical observations program, through the use of these tests. Data are compared. The results are: \circled1There is a significant difference between before and after instructions in the astronomy achievement test(t=11.31, p=000). \circled2There is a significant difference between before and after instructions in the astronomy teaching efficacy beliefs test(t=5.98, p=.000). \circled3There is a significant difference between before and after instructions in the scientific attitude test(t=270, pde. There fore, the a=.013). As a result, running an astronomical observations program has an effect on the preservice elementary teachers' astrono my achievement, astronomy teaching efficacy beliefs, and scientific attituuthor urges the teacher to teach astronomy through the astronomical observations in school.

• Hwankyungkyoyuk
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• v.21 no.2
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• pp.11-24
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• 2008

This research verifies the effect on environmental attitude and knowledge accomplishment by t-test as producing and running programs regarding global warming which is raised as a representative environmental issue subject to 6th grade-elementary students. For this, environmental education programs about global warming for elementary students are developed and applied 15 times by reconstituting classes based on the contents regarding global warming from the text books revised as of 7th course of study. The result is as below. First, some part of contents from social study and science of 6th grade elementary curriculum of 7th course of study was able to be reconstituted to 15 education programs. Secondly, the programs about global warming improved students' environmental attitude Application of the programs about global warming showed significant difference(p<.05) on building environmental attitude as it proved those are effective on both area of recognition level and practice level. The method used on the test had .866's Cronbach alpha modulus value therefore, it obtained reliability. Thirdly, the programs regarding global warming improved students' knowledge accomplishment. As a result of test for knowledge accomplishment which was executed with same method for attitude test, the application of the programs about global warming showed significant difference(p<.05) on improving students' knowledge accomplishment on the global warming therefore, it resulted that the application of the program is effective on knowledge acquirement.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.234-235
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• 2017

In order to improve the frictional resistance of existing high-speed planning hull, a step-like linear transformation has been researched which forms an air layer on the bottom. However, there is a lack of research on the proper position to confirm the effect of Running Attitude and step on each position. In this study, we confirmed the change of the Running Attitude, the effect of the step and the change of the frictional resistance when the step was applied in the longitudinal location.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.5
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• pp.349-355
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• 2014

The resistance test of a high speed craft such as planing ship is performed with a high speed towing carriage instead of ordinary towing carriage because of the speed limitation. In the resistance test using high speed towing carriage, the model ship is fixed to the carriage to restrain the running attitude for enough measuring time. Such method is called fixed model test method. In the fixed model test method, to get the appropriate running attitude, the model test is iteratively repeated until the trim moment and lift force are close to zero. In this research, trim free model test method is investigated to reduce the number of iteration. And, the limitation of towing speed range in the trim free model test method is investigated.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.3
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• pp.335-342
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• 2009

Motion characteristics of a planing craft are sensitively changed according to its weight and longitudinal center of gravity. In this paper, planing craft model tests were performed in calm water for various test conditions and Froude numbers. Sinkage and trim were measured to analyze the relations between the attitudes of a planing craft and the weight and center of gravity of it. Theoretical formula for the prediction of the attitudes of a prismatic planing hull was modified so that it can be applied to the prediction of the attitudes of a non-prismatic planing hull, and the calculation results by the modified formula were in good agreements with the experimental data.