• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1995.06b
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• pp.1.1-4
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• 1995

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.1
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• pp.63-70
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• 2017

In this paper, we design and fabricate a de-orbiter using drag-sail and evaluate deployment characteristics. Without employing an actuator to deploy, the de-orbiter is activated by the SMA wire based the release mechanism and driven by the restoring force of the tape-spring. For efficient storage and deployment of drag-sail, an origami method of original ISO flasher is chosen and low priced mylar film is used as the material of the drag-sail. In addition, through the fault tree analysis method which is one of the one-shot device reliability evaluation methods, we confirm the reliability of the de-orbiter(0.997572) and the Roller failure has the highest criticality. Finally, we find feasibility of the proposed de-orbiter through the deployment demonstration of drag-sail.

• Proceedings of KOSOMES biannual meeting
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• 2007.11a
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• pp.91-95
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• 2007

It tries to develop a collect system for floating garbage flowed into the sea Based on the study on the characteristics of floating garbage in rainy season, it confirmed the structure and specification of each device and tested its performance on the sea It showed tint the collection device of this system could sweep more than 15 meters of sea area at a time when a ship moves with the efficiency of the spreading device. It means tint it is more efficient in collecting garbage than now in use garbage collecting ships. The water height of the net to which the garbage is finally input maintained more 50cm within the towing speed of 5kt. It indicates tint the garbage input performance is good The collect system of this research showed good performance collecting 200kg of garbage into the net for each test of collecting floating garbage.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.4
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• pp.333-340
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• 1990

The authors carried out a visiualizational model test by the hydrogen bubble method to examine the pattern of the fluid flow besides the simple camber type and plane type otter board in circulation water channel. The experimental conditions are velocity of flow 0.05 and 0.1m/sec, angle of attack 0$^{\circ}$~45$^{\circ}$(5$^{\circ}$step). The results obtained are as follows: 1. In the case of the simple camber type otter board located angle of attack 25$^{\circ}$, vortex at the leading edge was geneated at 1/2 of chord length. 2. Size of the vortex generated in the trailing edge was about 2~3 times larger then that of the leading edge. 3. In the case of the simple camber type otter board located angle of attack 30$^{\circ}$, separation of stream-line at leading edge was generated at 1/3 of chord length. 4. Nearest stream-line in the back side of the simple camber type otter board was bent in the direction of otter board when the angle of attack was 25$^{\circ}$ and 30$^{\circ}$, and in the case of plane type otter board was expanded outside of the flow direction. 6. Area separated of the simple camber type otter board at the angle of attack 30$^{\circ}$ was smaller then that of plane type otter board. 7. Flow speed in the back side of the simple camber type otter board was about 1.4 times faster then that in the front side, and in the case of the plane otter board about 1.2 times faster.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.1-7
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• 1985

Various types of shearing devices which may be a substitute for the conventional beams in stow nets were considered, and then tentatively named "the zonal canvas type of stow net" having the shearing device made of zonal canvas was devised. A 1/3 model of the net was made and experimented at sea. Converted to the full scale, the measured water resistance R(kg) of the net was given by $R=5.6{\times}10^{3}V^{l.5}$ or $R=3.5\frac{d}{l}{\lambda}_b{\lambda}_l\;V^{1.5}$, where V is the water velocity (m/sec), d the diameter of netting bars, l the length of the bars, ${\lambda}_b$ the stretched circumference of net mouth (m), ${\lambda}_l$ the length of net stretched. The net height kept about $83\%$ of the side rope length regardless of the variation of V and the net breadth kept a value over $90\%$ of the head rope length until V reached 1 m/sec. These results were very successful according to expectation, but the conventional netting was requested a further improvement. Therefore, the netting was newly designed to have smaller size of meshes in the vicinity of net mouth and larger hanging ratio breadthwise. With the netting a full scale net was made and experimented by a stern trawler. The experiment gave a net breadth over $95\%$ of the head rope length until V reached 1m/sec and showed no faults in the net. But the net operation by the stern trawler was ascribed an inconvenience to its narrow breadth of stern slip way.

• Journal of the Korean association of regional geographers
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• v.19 no.4
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• pp.787-804
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• 2013

The purpose of this study is to explore the effect of 'World Cafe' conversations for collective intelligence. For this purpose, 'World Cafe' was applied to the class 'presentation and discussion' of university class. To explore the effect of 'World Cafe' conversations for collective intelligence I surveyed the responses of students participating in the class and analyzed results of the survey and class activities. The results are as follows: first, 82 percent of all students were actively involving in the class, second, topics were more discussed through World Cafe class than general discussion class. These results suggest 'World Cafe' class induced active participation of the students in class and have the effect producing the collective intelligence.

• Journal of the Korean Chemical Society
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• v.50 no.5
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• pp.374-384
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• 2006

this study, the teaching methods of three science teachers for lead-iodide precipitation reaction experiment were compared. The difference of 9th grade students' understanding was searched according to the science teachers teaching styles, also. Among the three teachers, Teacher A taught students based on the science textbook and allowed students to think themselves and to get out conclusion by the experiment. Teacher B and Teacher C gave students a lot of explanations related to interpretation of the experiment. The percentage of no response on the experiment report of Teacher A was higher than those of Teacher B and Teacher C. But the students of Teacher B and Teacher C tended to have limited thoughts because of the teachers explanations. In spite of the difference, it was common phenomenon that few students understood concepts through the experiment. A lot of students were interested in the experiment, but it was hard to understand Law of definite proportions according to the experiment.

• The Journal of the Korea Contents Association
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• v.14 no.1
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• pp.56-65
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• 2014

Most of experimental films have different visual techniques and aesthetic values compared to those of narrative films. This difference makes it difficult to understand experimental films. In order to understand in what ways the experimental film has broken with the convention of narrative film, it is important to examine certain structure of experimental film. The important aspect of many experimental films is the way that they have altered the nature of narrative by changing the way that we perceive the succession of image. In particular, The tradition of American Sturcture film has been the contribution of the experimental film to expand the limits of this rule system and evolve a more personal and organic approach to the continuum of film. This approach has been a method of understanding experimental films and still a useful aesthetic tools both reading personal films and making innovative works.

• Journal of Music and Human Behavior
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• v.19 no.1
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• pp.93-112
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• 2022

The purpose of this study was to compare participants' perceived emotion following harmonic changes in music. In this study, 144 participants, aged 19 to 29 years, listened to music online that included low to high harmonic progression in tonal music (major-minor). After listening to each piece of music, participants were asked to rate 4 items using a 7-point Likert scale: emotional potency, arousal, degree to which the harmony impacted the listener's emotions, and listener's preference for the music. There were significant differences between each of the four items upon the level of harmonic progression. When the participants were divided into two groups (i.e., those with a background in music and those with no background in music), there was a significant difference between the groups in terms of emotional potency, but there was no significant interaction effect. This study confirmed that various emotional responses in listeners can be induced by controlling the exogenous variables in musical excerpts. Based on this, it is expected that the harmonic progression level can be provided to the client to be used as an effective therapeutic tool in music therapy intervention.

• Journal of Korea Water Resources Association
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• v.33 no.6
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• pp.805-814
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• 2000

A numerical model based on the boundary element method is employed to describe diffraction of monochromatic water waves due to varying topographies. The model is firstly verified by comparing obtained reflection and transmission coefficients of waves over a trench to those of the eigenfunction expansion method. The model is then used to investigate the Bragg reflection of waves over sinusoidally varying topographies. Calculated reflection coefficients are compared to available laboratory measurements and semi-theoretical results. A reasonably good agreement is observed.served.