• Title/Summary/Keyword: Kite

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The hydrodynamic characteristics of the canvas kite - 2. The characteristics of the triangular canvas kite - (캔버스 카이트의 유체역학적 특성에 관한 연구 - 2. 삼각형 캔버스 카이트의 특성 -)

  • Bae, Bong-Seong;Bae, Jae-Hyun;An, Heui-Chun;Lee, Ju-Hee;Shin, Jung-Wook
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.40 no.3
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    • pp.206-213
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    • 2004
  • As far as an opening device of fishing gears is concerned, applications of a kite are under development around the world. The typical examples are found in the opening device of the stow net on anchor and the buoyancy material of the trawl. While the stow net on anchor has proved its capability for the past 20 years, the trawl has not been wildly used since it has been first introduced for the commercial use only without sufficient studies and thus has revealed many drawbacks. Therefore, the fundamental hydrodynamics of the kite itself need to ne studied further. Models of plate and canvas kite were deployed in the circulating water tank for the mechanical test. For this situation lift and drag tests were performed considering a change in the shape of objects, which resulted in a different aspect ratio of rectangle and trapezoid. The results obtained from the above approaches are summarized as follows, where aspect ratio, attack angle, lift coefficient and maximum lift coefficient are denoted as A, B, $C_L$ and $C_{Lmax}$ respectively : 1. Given the triangular plate, $C_{Lmax}$ was produced as 1.26${\sim}$1.32 with A${\leq}$1 and 38$^{\circ}$B${\leq}$42$^{\circ}$. And when A${\geq}$1.5 and 20$^{\circ}$${\leq}$B${\leq}$50$^{\circ}$, $C_L$ was around 0.85. Given the inverted triangular plate, $C_{Lmax}$ was 1.46${\sim}$1.56 with A${\leq}$1 and 36$^{\circ}$B${\leq}$38$^{\circ}$. And When A${\geq}$1.5 and 22$^{\circ}$B${\leq}$26$^{\circ}$, $C_{Lmax}$ was 1.05${\sim}$1.21. Given the triangular kite, $C_{Lmax}$ was produced as 1.67${\sim}$1.77 with A${\leq}$1 and 46$^{\circ}$B${\leq}$48$^{\circ}$. And when A${\geq}$1.5 and 20$^{\circ}$B${\leq}$50$^{\circ}$, $C_L$ was around 1.10. Given the inverted triangular kite, $C_{Lmax}$ was 1.44${\sim}$1.68 with A${\leq}$1 and 28$^{\circ}$B${\leq}$32$^{\circ}$. And when A${\geq}$1.5 and 18$^{\circ}$B${\leq}$24$^{\circ}$, $C_{Lmax}$ was 1.03${\sim}$1.18. 2. For a model with A=1/2, an increase in B caused an increase in $C_L$ until $C_L$ has reached the maximum. Then there was a tendency of a very gradual decrease or no change in the value of $C_L$. For a model with A=2/3, the tendency of $C_L$ was similar to the case of a model with A=1/2. For a model with A=1, an increase in B caused an increase in $C_L$ until $C_L$ has reached the maximum. And the tendency of $C_L$ didn't change dramatically. For a model with A=1.5, the tendency of $C_L$ as a function of B was changed very small as 0.75${\sim}$1.22 with 20$^{\circ}$B${\leq}$50$^{\circ}$. For a model with A=2, the tendency of $C_L$ as a function of B was almost the same in the triangular model. There was no considerable change in the models with 20$^{\circ}$B${\leq}$50$^{\circ}$. 3. The inverted model's $C_L$ as a function of increase of B reached the maximum rapidly, then decreased gradually compared to the non-inverted models. Others were decreased dramatically. 4. The action point of dynamic pressure in accordance with the attack angle was close to the rear area of the model with small attack angle, and with large attack angle, the action point was close to the front part of the model. 5. There was camber vertex in the position in which the fluid pressure was generated, and the triangular canvas had large value of camber vertex when the aspect ratio was high, while the inverted triangular canvas was versa. 6. All canvas kite had larger camber ratio when the aspect ratio was high, and the triangular canvas had larger one when the attack angle was high, while the inverted triangluar canvas was versa.

The Development of Midwater Trawl Net in North Pacific Ocean (북태평양(北太平洋) 중층(中層)트롤그물의 발달(發達))

  • Kwon, Byeong-Guk;Chang, Ho-Young
    • Journal of Fisheries and Marine Sciences Education
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    • v.6 no.1
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    • pp.11-19
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    • 1994
  • The North Pacific midwater trawling which is one of the important fishing methods for Korean fishing industry is working in the Bering Sea and the sea near Kamchaka Peninsula. The catch by Korean midwater trawlers had been recorded about 300 thousands $^{M/_T}$ a year. Six types of midwater trawl net-ordinary midwater trawl net, super-V trawl net, super mesh trawl net, rope trawl net, super plus trawl net and kite trawl net-have been widely used by large trawlers above 1,500gt in size since 1982. Regarding the fishing efficiency, the super plus trawl net and kite trawl net were acknowledged as higher than other nets. Maximum mesh size of super-plus trawl net and kite trawl net ranges about 20m, whereas the length of net about 150m, and high-tech polyethylene is used as the material of rope part. The problems involved in the North Pacific midwater trawl net may be summarized as follows ; (1) The dimension of fishing gear is too big compared with the towing power of trawler. (2) The mesh size of the rope part is too big compared with that of the common netting part. (3) The net is often torn out in the connecting position of the rope part and the netting part. (4) The net is not matched with the trawler and the otter board in many trawlers, so the shape of the trawl gear in the water is instable. (5) The fish school located near head rope, ground rope and side rope in the net recorder is not caught in practice because of the net instability.

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Analysis of Pre-service Elementary School Teachers' Responses to MKT Applying Task - Focused on Kite (MKT 적용과제에 나타난 초등예비교사의 반응 고찰 - 연꼴을 중심으로)

  • Kwon, Sung-Yong
    • School Mathematics
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    • v.14 no.2
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    • pp.255-274
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    • 2012
  • The purpose of this study was to investigate the responses of pre-service elementary school teachers to the task that require to apply mathematics knowledge for teaching and from this investigation to draw some conclusions about teacher education. To do the study, task was to develop teaching materials and devise lesson plan for introducing the concept of plain figure 'kite'. For gathering data, 77 pre-service elementary school teachers were selected from the University of Education located in G city. Several conclusions were drawn as follow: first, task for applying MKT is needed to check whether pre-service teachers can apply. Second, assessment is needed to check what kind of MKT do pre-service elementary school teachers have.

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Effects on hematology and blood biochemistry profile of intramuscular meloxicam injection in Brahminy kite and Barn owl

  • Ratiwan Sitdhibutr;Raveewan Ploypan;Sirawit Subaneg;Chaiyan Kasorndorkbua
    • Journal of Veterinary Science
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    • v.24 no.3
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    • pp.43.1-43.8
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    • 2023
  • Background: Meloxicam is used widely for exotic animal analgesia, but its toxicity in common raptor species in Thailand is unclear. Objectives: This study evaluated the single-dose effect of intramuscular meloxicam in common raptor species in Thailand for short-term and long-term periods. Methods: Twenty-two raptors were administered a single 1 mg/kg dose of meloxicam individually via intramuscular injection. The following were evaluated: clinical appearance, body weight, body condition score, body temperature, fecal appearance, complete blood cell count, and biochemistry panel before (day 0) and after the injection (1, 7, and 30 days). The collected samples were categorized into three groups: Brahminy kite (Haliastur indus) (n = 10), adult Barn owl (Tyto javanica) (n = 4), and juvenile Barn owl (n = 8). Results: None of the raptors in the study groups showed any abnormalities. The hematological profiles were significantly different in the short-term period (day 1 and day 7). The creatinine, aspartate aminotransferase, and creatinine kinase increased in several groups. On the other hand, the packed cell volume decreased in the Brahminy kite and juvenile Barn owl groups. According to the findings, an intramuscular injection of 1 mg/kg meloxicam affected the blood biochemistry panel of the muscle, but the affected raptors recovered within one week. Conclusions: An intramuscular injection of meloxicam at a single 1 mg/kg dose in Brahminy kites and Barn owls was not associated with the morbidity, hepatotoxicity, gastrointestinal toxicity, and nephrotoxicity in the short- and long-term periods.

The characteristics of the flow field around canvas kite using the CFD (CFD를 이용한 범포 주위의 유동장 특성)

  • Bae, Bong-Seong;Bae, Jae-Hyun;An, Heui-Chun;Park, Seong-Wook;Park, Chang-Doo;Jeong, Eui-Cheol
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.42 no.3
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    • pp.169-178
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    • 2006
  • This research aims at establishing the fundamental characteristics of the kite through the analysis of the flow field around various types of kites. The approach of this study were adopted for the analysis; visualization by CFD(computational fluid dynamics). Also, the lift/drag and PIV(particle image velocimetry) tests of kites had been performed in our previous finding. For this situation, models of canvas kite were designed by solidworks(design program) for the CFD test using the same conditions as in the lift/drag tests. And we utilized FloWorks as a CFD analysis program. The results obtained from the above approach are summarized as follows: According to comparison of the measured and analyzed results from mechanical tests, PIV and CFD test, the results of all test were similar. The numerical results of lift-coefficient and drag-coefficient were 5-20% less than those of the tests when attack angle is $10^{\circ},\;20^{\circ}\;and\;30^{\circ}$. In particular, it showed the 20% discrepancy at $40^{\circ}$. The numerical results of the ratio of drag and lift were 8-13% less than those of the tests at $10^{\circ}$ and 10% less than those of the tests at $20^{\circ},\;30^{\circ}\;and\;40^{\circ}$. Pressure distribution gradually became stable at $10^{\circ}$. In particular, the rectangular and triangular types had the centre of the high pressure field towards the leading edge and the inverted triangular type had it towards the trailing edge. The increase of the attack angle resulted in the eddy in order of the rectangular, triangular and inverted triangular type. The magnitude of the eddy followed the same order. The effect of edge-eddy was biggest in the triangular type followed by the rectangular and then the inverted triangular type. The action point of dynamic pressure as a function of the attack angle was close to the rear area of the model with the small attack angle, and with large attack angle, the action point was close to the front part of the model.

The symbolic signs in Ontology and its philosophical development (주자 천도론의 상징부호와 철학적 전개)

  • Kang, jinseok
    • The Journal of Korean Philosophical History
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    • no.23
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    • pp.393-421
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    • 2008
  • This thesis has an intention to reorganize the topic of Ontology that has not unnoticed, investigating the symbolic signs of Zhuxi. The symbols in Ontology visualize in an anthropomorphic form or a form of animals that we can usually find in the nature. The visible symbols have characteristics of the dynamic rather than the stillness. The symbols of human and a horse have developed as different interpretations depending on the relative importance. The movement of stream symbolize the Movement of Daoti that manifests thorough all things in the Dao and have a structure of 'Ti-Xiang-Yong'. The Substance of Metaphysics embodies an action thorough 'Metaphysics' or 'with Metaphysics'. Accordingly, 'a stream' symbolizes 'the Movement of Daoti' in that it manifests the form of Daoti makes body. A kite and a fish symbolize the form of a kite flies up into the sky and the shape of a fish plays in the pond. These not only represent an outlook on the world, but also symbolize the stage of the Movement of Daoti. 'Human', 'a stream', 'a kite' and 'a fish' include activeness, domination, dynamics, manifestation, visibility, naturalness.

The Error Diffusion Halftoning Using Local Adaptive Sharpening Control (국부 적응 샤프닝 조절을 사용한 오차확산 해프토닝)

  • 곽내정;양운모;윤태승;안재형
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.41 no.4
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    • pp.87-92
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    • 2004
  • Digital halftoning is to quantize a grayscale image to binary image. The error diffusion halftoning generates high quality bilevel image. But that also has some defects such as warms effect, sharpening and etc. To reduce these defects, Kite proposed the modified threshold modulation that has a parameter to control sharpening. Nevertheless some degradation left near edges with large luminance change. In this paver, we propose a method to control the parameter in proportional to local edge magnitude. The results of computer simulation show more reductions of the sharpening in the halftone image. Especially there are great improvement of quality near edges with large luminance change.

Developing an Art-based Integration Program for the Korean Schools in the United States

  • Jung, Hyunil
    • International Journal of Advanced Culture Technology
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    • v.6 no.1
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    • pp.1-7
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    • 2018
  • The purpose of this study is to develop an art-based integration program for the Korean schools in the United States to improve students' academic performance and nurture the spirit of the young and can enable students taking art classes to better understand social and cultural phenomena influencing their lives. This study integrates with six other subjects that are language art, math, religion, social studies, and Korean history. Art classes are considered the main vehicle for integrating the entire program using a thematic approach. The methodology of this study is based on the literature research and the information of the place, the Korean School of Columbus, is that the school is one of 124 Korean Schools in the Mid-western states and is located in the northern part of Columbus, Ohio. In this study, I developed an art-based integration program to be connected well with other subjects to help students to make sense of them in the complex societies and to help them to obtain the five goals that are included: First, students will understand about a Korean history and culture through making a kite; Second, they will know that a kite can be used as ways of communication with people and God; Third, they will also know how different types of kites respond to the airflow of the wind; Fourth, they will understand an enjoyable and different way of learning about aspects of Fine art, Bible, Language art, Mathematics, Science, History, and Social studies; Lastly, they will learn how important to cooperate with each other.

무부자 쌍끌이 중층망의 전개성능에 관한 모형실험 - 카이트를 이용한 무부자망의 전개성능 관하여 -

  • 유제범;이주희;권병국;김정문
    • Proceedings of the Korean Society of Fisheries Technology Conference
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    • 2001.10a
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    • pp.35-36
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    • 2001
  • 전보의 무부자망은 해상시험 조업의 결과, 망구의 전개 및 중ㆍ저층에서의 예망수층 조절등이 손쉽게 이루어지는 것이 확인되었으나 뜸줄부가 표층 ∼ 30m에서의 예망수심조절이 어렵다는 것이 확인되었다. 따라서, 무부자망은 망구전개가 F.W(Front weight)의 침강력에 의하여 이루어지므로 어구의 예망수심의 깊이 조절이 한계를 받으므로 이것을 극복하기 위하여 카이트(Kite)를 도입하기로 하고 본 연구를 실시하였다. (중략)

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