• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.648-651
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• 2010

Propeller shall have high efficiency and improved aerodynamic characteristics to get the thrust to fly at high speed for the FAR25 turboprop aircraft. That is way Clark-Y airfoil which is used to conventional turboprop aircraft propeller is selected as a blade airfoil. Javaprop program based on the Adkins method is used for aerodynamic design and analysis of propeller, Adkins method is based on the vortex-blade element theory which design the propeller to satisfy the condition for minimum energy loss. Slipstream displacement don't change and consider a rigid body. High efficiency propeller geometry is generated by varying chord length and pitch angle at design point of FAR25 turboprop aircraft. The propeller design results indicate that could be applied to the FAR25 turboprop aircraft, through analysis of propeller aerodynamic characteristics using the CFD(Computational Fluid Dynamic).

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.2
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• pp.94-101
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• 2016

In this paper, aerodynamic effects on the flow field under the wing with varying aspect ratio were investigated by measuring pressures on the lower surface of wing and analysing velocity components using Particle Image Velocimetry at Reynolds numbers of $1.384{\times}10^5$ and $2.306{\times}10^5$. In case of aspect ratio 4.8 which keeps the wing tip at a distance of 80% chord length from the pylon, the vortex from the wing tip influenced the flow field under the wing by reducing static pressures on the lower surface and increasing the velocity in proximity of the wing tip. Throughout the results, it is observed that aerodynamic effects of wing tip on the flow field around pylon under wing become insignificant as the aspect ratio increases.

• Convergence Security Journal
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• v.11 no.5
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• pp.109-120
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• 2011

How meteorological situations have affected human life for survival have been an important element of living or military strategy throughout history. In modern society, overcrowding of cities has brought about many problems. Moreover, high-rise buildings and land cover have been causing abnormal weather conditions. The wind corridor, especially in urban areas has been flowing differently from the dominant weather condition of the surroundings. Therefore, the wind corridor in urban areas can be a main component in protecting major national facilities in urban areas from damage. Especially the wind corridor is a main factor to derive harm from poisonous substances in air. This paper seeks to find out the wind corridor in urban areas and the efficiency of that. In addition to that, it studies how to use the direction to protect major national facilities and areas from damage. It is considered that this study will be useful to make defence project, not only for preventing CBR(chemical, biological, and radiological) terrorism and violent assembly, but also for evacuation of people in case of big accidents or natural disasters.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.5
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• pp.359-366
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• 2017

In this paper, aerodynamic data of the Gaori kite was constructed through the wind tunnel experiment taking into consideration all the angles of attack formed during the flight of the Gaori kite. From this aerodynamic data, we made a morphing analysis of the relative length of the front bridle to the rear bridle required to achieve equilibrium flight as the angle of attack of the Gaori kite or the azimuth angle change. As a result, it was found that the relative length of the front bridle to the rear bridle depends entirely on the chord length of the kite, the relative wind speed and changes morphed according to the angle of attack. Using this information data, one can adjust the relative length of the bridle line to suit the kite attitudes and flight environments handling the kites that maintain optimal flight performance.

• Journal of Korean Medical classics
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• v.20 no.1
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• pp.75-84
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• 2007

본논문천명(本論文闡明) "류경(類經)" 위안등창익의학사상적천원(爲安藤昌益醫學思想的泉源), 종안등창익학습(從安藤昌益學習) "류경(類經)" 적계단래비판(的階段來批判) "류경(類經)", 집중적연구관찰극복계단적전화과정(集中的硏究觀察克服階段的轉化過程). 안등창익(1703-1762)재일본강호시대시개즉독창우진보적사상가야시중의사(安藤昌益(1703-1762)在日本江戶時代是個卽獨創又進步的思想家也是中醫師). 타통과(他通過)'자연진영도(自然眞營道)'등굉대적저술(等宏大的著述), 부근논술료사회철학급자연철학(不僅論述了社會哲學及自然哲學), 이차재일본의학사상난이발현적독특적의학사상급여체계화(而且在日本醫學史上難以發現的獨特的醫學思想給與體系化). 타이유교비판위기초(他以儒敎批判爲基礎), 비판중국의학대유유의적경향(批判中國醫學帶有有醫的傾向), 여후세파(與後世派), 고방파적맥락야부동(古方派的脈絡也不同), 독자제정일본의학(獨自制訂日本醫學). 타대어중국적음양오행설이진퇴론화사행팔기적호성론래대항(他對於中國的陰陽五行設以進退論和四行八氣的互性論來對抗), 대어'내경'적국가유추(analogy)내장관이유기생체적내장관래대치(對於‘內經’的國家類推(analogy)內臟觀以有機生體的內臟觀來對峙). 병차비판숙명론적운기론이제창대소우주론적생태학(ecology)적의학. 이차간래(以此看來), 안등창익적의학사상시이비판'내경'위개단(安藤昌益的醫學思想是以批判‘內經’爲開端). 아문가이통과안등창익적운기론적비판래명백(我們可以通過安藤昌益的運氣論的批判來明白), 타대'내경'적이해시의거장개빈적 "류경"(포괄'도익'화'부익')(他對'內經'的理解是依據張介賓的"類經"(包括'圖翼' 和 '附翼')). 안등창익일방면계승장개빈적운기론영일방면야지유비판적태도. 타주장십기래대체십간(他主張十氣來代替十干), 인위군화여상화시파군신적상하관계정당화(認爲君火與相火是把君臣的上下關係正堂化), 인이반대저양적사고방식(因而反對這樣的思考方式). 병차안등창익부정기성적음운학, 제창자연적운도(提唱自然的韻道), 아문가이확인대어타적사상장개빈적 "류경" 시위중요적기초(我們可以確認對於他的思想張介賓的 "類經" 是爲重要的基礎).

• The Southeast Asian review
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• v.23 no.1
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• pp.169-194
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• 2013

A Korean writer, Yi Soonwon's The Face and a Thai writer, Win Lyovarin's Three Worlds of Rat Ekathet symbolize into literature the historical demonstration which occurred in Korea and Thailand. Comparing the characters in these two works, we come to the conclusion that the background in which people use violence strongly relates with their emotion. The character in The Face commit emotional violence in which receiving education and training and having jostled situation were sprouted as hostility. On the other hand, the characters in Three Worlds of Rat Ekathet show the difference in the sense that they feel a pleasant sensation when they use violence, intoxicated in the power of violence. One thing that two works have in common is that people committing a sin suffer from a guilty conscience and guilty fears when we see the way to treat them. It is how psychological punishment is made by their own. In The Face, the character suffers from psychological punishment in the fear that the other may be aware of his past record when we see the difference to deal with emotional violence. That who committed violence not to be able to open up honorably can never be free from the judgement of conscience out of the law and the sense of guilt continues for his life. However, emotional punishment made by a guilty conscience in Three Worlds of Rat Ekathet has the limited period if sinners make the process of purification which means not committing a fault again. The ultimate way of treating those who committed violence is to forgive them with love and is the process of purification to change violence into non-violence.

• Journal of Korean Library and Information Science Society
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• v.53 no.2
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• pp.241-264
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• 2022

The Studies related to the Gwangju Student Movement which occurred in 1929 have been diversified on research topics since 2018. A number of studies have been conducted on the process of spreading the Gwangju Student Movement abroad. However, those studies show limitations in terms of difficulty in discovering new historical materials and the absence of research methods. Therefore, the researchers have analyzed the process of spreading Gwangju Student Movement abroad as the process of spreading information based on library and information science. The researchers have newly discovered Chinese newspaper records at that times and conducted 2-mode network analysis. The results are as follows: first, 125 Chinese newspaper records were discovered from 16 kinds of newspapers and 104 articles of them were newly discovered; second, the researcher found that there were earlier articles than the first claimed by previous researchers in their studies; third, Newspapers in Beijing, Sacheon, Shanghai, Tianjin, and Honam regions in China mainly reported the first and second joint demonstrations in Seoul and Gwangju. The significance of this study is to expand and diversify the research on the Gwangju Student Movement through network analysis.

• Korean Journal of Legislative Studies
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• v.15 no.2
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• pp.131-158
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• 2009

20 years has passed since June democratization movement of 1987 that made the representative system worked democratically on the basis of free election politics. So far, democratic movement bloc has been elected to government power at least two times. Conservative bloc of old ruling forces made a peaceful re-turn-over and grasped the government power. It looks that electoral democracy has been working very well. But people's distrust in Korean politics is not decreasing. Recently, crisis of representation is discussed. Korean representative system faces the dual tasks. One originates from the delay of institutional reform, another from the change of political circumstances. This paper diagnose the Korean representative democracy of today, focusing on those dual tasks. Especially, it is proposed to reform the present Korean presidentialism of winner-takes-all power structure. It is also to resolve the problem of Korean parliamentary politics deeply depending on the presidency.

• Korean Journal of Heritage: History & Science
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• v.56 no.1
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• pp.142-160
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• 2023

The position of the people who participated in the Bapyo Ritual held in the reign of King Sejong and the corresponding costumes were examined. The king, who was the executive body of the ritual, wore Myeon-Bok, a court dress, and Myeon-Bok was Gujang-Bok made of Jang-wha on Guryu-Pyeongcheongwan. Crown princes, royal families, and government officials wore Oryang-Gwan and Jekraeui, which were Jobok. The crown princes' Joboks were changed from Oryang-Gwan to Wukryang-Gwan in the dynasty year 10 of King Sejong, and in the year of King Munjong's accession, Myeon-Bok was received, and after King Danjong, the crown princes wore Palryu-Pyeongcheongwan and Chiljang-Bok. Diplomats and Jongsagwan who were the envoys wore Sangbok. A Sangbok worn by the diplomat was Samo with Danryeong, Seo-Dae, and Hyeopgeum-Hwa, and a Sangbok worn by Jongsagwan was Samo, Danryeong, Heukgak-Dae, and Heukpi-Hwa. Byulgam, who served as an attendant to the king in the king's close quarters, wore Gongbok and Sangbok. Gongbok consisted of Ja-Geon, Danryeong and Heukpi-Hwa, and Sangbok consisted of orange color Cho-Rip, Jikryeong, Joa, and Heukpi-Hwa. The person holding San, Gae , Sujeongjang, and Geumwolbu wore Ja-Geon and Cheong-Ui, and Seon wore Pimoja and Hong-Ui. Siwigun wore armor and helmets equipped with weapons. Among court musicians, Aksa's costumes consisted of Bokdu, Bigongbok, Geumdonghyeokdae, Bibaekdaedae, and Opiri, and Aksaeng's one composed of Gaechaek, Bisuransam, Hyupgo, Mal, Maldae, and Opiri. As a result of the above, the process of ceremonial clothes becoming uniform clothes in the reign of King Sejong was confirmed. The king and lower-ranking officials such as crown princes, government officials, diplomats, Byulgam, armies for ceremonial weaponry, and court musicians participating in the Bapyo Ritual wore the highest grade of ceremonial clothes for each class. King Sejong had repeated discussions to build a nation based on Confucianism, and arranged each rite and corresponding costume, and the Bapyo Ritual costume was also systematically prepared for each position. The ceremonial clothing organized during the reign of King Sejong was regulated in Yejon and became the basis for continuing to the late Joseon Dynasty.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.59-59
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• 2017

무인 헬리콥터의 양력을 개선하기 위한 익형 설계 단계로서 두꺼운 익형(V1505A)과 얇고 처진 익형(V2008B)의 기본 두 익형의 특성을 예측하는데 있어 회전하는 블레이드의 현실적 조건을 반영한 3D 모델을 마련하고 성능을 예측하였다. Fluent를 이용한 400 mm 선형모델의 시뮬레이션에서는 V1505A 익형은 높은 받음각에서 안정적인 특성을 보인 반면 V2008B는 비교적 높은 동력효율 특성을 보였으나, 높은 받음각에서는 실속 이후 양력이 급락하는 특성을 나타낸다. 형성된 노드 수는 약 870,000개로 하였다. 시위길이 135 mm인 익형 V2008B의 형상은 ANSYS (Fluent v16.2)를 이용해 반경(길이) 1,502 (1,380) mm 의 로터 블레이드를 구성하였다. 충분하지 않은 유동장이 익형 표면에서의 유동의 영향에 영향을 주지 않도록 직경 20 m의 원방경계(far field)를 형성하였다. 사용된 매쉬의 형태는 정사면체 형태로 로터 표면으로부터의 첫 번째 두께 높이는 0.001 m이고 10개의 층으로 형성하였다. 정지 비행하는 헬리콥터의 상태를 가정하여 회전좌표계를 이용하여 정상상태의 유동을 해석하고 사용된 난류모델은 넓은 영역에서의 유동을 고려하여 Realizable $k-{\varepsilon}$ 모델을 사용하였다. 내측그립 받음각 $6{\sim}22^{\circ}$에 대하여 현실적인 회전속도를 연동하여 600~1000 rpm을 적용하였다. 반복수(iteration)는 2000으로 하여 잔차값(residual)이 충분히 수렴하도록 하였다. 전체적으로 실제 헬리콥터가 발휘하는 양력보다는 낮은 수치로 예측되었으며 모델 및 해석 조건에 대한 검토가 필요해 보인다. 양력 값은 받음각 $10^{\circ}$에서 자중(약 68 kgf)을 극복하였고 받음각 $12^{\circ}$에 유상하중 20 kgf을 발휘하며 888 N의 양력을 보였다, 이어 받음각 $22^{\circ}$에서 실속 현상이 발생하였다. 받음각이 증가함에 따라 항력 역시 증가하였으며 받음각 $12^{\circ}$에서 121 N이었고 실속에 이르며 항력은 갑자기 증가할 것으로 예측된다. 본 연구는 변이 익형 개발의 선행 단계로 기본 익형에 대한 공력특성을 CFD 시뮬레이션을 통하여 예측하였다. 예측 값은 현실적 실험방법을 통하여 검증이 되어야 하며 이후 변이익형에 대한 예측과 설계가 가능하다.