• Title/Summary/Keyword: 조청

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An Experimental Study on Water-Purification Properties of Porous Concrete Utilizing Recycled Aggregate (재생골재를 사용한 포러스 콘크리트의 수질정화 특성에 관한 실험적 연구)

  • 김정환;조광연;조청휘;이봉춘;박승범
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.925-928
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    • 2001
  • Recently great efforts and investment have been made in order to achieve economical production by applying new methods like minimization of man-Power into construction field. This paper describe the performance of water purification, to which living organisms can adapt, and the physical properties of porous concrete with continuous voids. Although conventional concrete has been regarded as a destroyer of nature, water and air can pass freely through concrete when it is made porous by forming continuous voids. this not only enables plants to vegetables, but also makes it possible for microscopic animals and plants, including bacteria, to attach to and inhabit uneven surface as well as internal voids when the concrete is provided in a natural water area or waterside area. As a result, Porous concrete using recycled aggregate improved the performance of water purification.

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Development of Modeling Tool for Implicit Surface using Parametric Curve (매개변수 곡선을 이용한 음함수 곡면의 모델링 도구 개발)

  • Park, Sangho;Jho, Cheung Woon
    • Journal of Korea Multimedia Society
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    • v.19 no.11
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    • pp.1900-1908
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    • 2016
  • Recent times have seen the introduction of modeling technologies using implicit surface and marching cubes algorithm in the field of computer graphics. Implicit surface modeling is used to express characters or fluid. This study presents a calculation method for the density of curve skeletal primitives using parametric curve and implements an implicit surface modeling tool by utilizing Maya API. Skeletal primitives can be assembled and utilized in character modeling using the implemented modeling tool. Results could be obtained more effectively compared to existing particle-based methods.

Truncation Error Problem of Error Diffusion Method (오차 확산 방법의 절삭 오차 문제)

  • Jho, Cheung-Woon
    • Journal of Advanced Navigation Technology
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    • v.15 no.5
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    • pp.850-856
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    • 2011
  • The error diffusion method is one of the digital halftoning methods that diffuses quantization errors of current processing pixel to neighboring pixels and get a high-quality black-white image. This method has the problematic case which partially increase or decrease summation of diffused errors in the process of diffusing the quantization error. In this paper, we analyze Floyd-Steinberg method, Jarvis-Judice-Ninke method, Stucki method, and Shiau-Fan method as a representative case of error diffusion methods and propose a solution method of this problem.

An Experimental Study on the Mechanical Properties of Fiber Reinforced Permeability Concrete (섬유보강 투수 콘크리트의 역학적 특성에 관한 실험적 연구)

  • 이봉춘;조청휘;박승범
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10a
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    • pp.665-670
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    • 2000
  • In this study mechanical properties of various fiber reinforced permeability concrete mixtures are investigated. Several mixes with fiber kinds(steel fiber, polyprophylen fiber, carbon fiber) and different fiber content(steel fiber : 0.3~0.9vol.%, polyprophylen fiber : 0.1~0.5vol.%, carbon fiber : 0.2~0.7vol.%) were studied. Test results are presented in terms of compressive strength, tensile-flexural strength and load-deflection behavior. The effect of fiber reinforcement does not increase the compressive strength of permeability concrete without fiber. Also, the tensile-flexural strength using various fibers are appeared good strength increase as conventional fiber reinforced concrete. Therefore, use of fiber for permeability concrete is necessary to improve of tensile-flexural properties and deformation performance(toughness).

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A Experimental Study of Flexible Rubber Packing Materials of Precast Concrete Pipeline (프리캐스트 콘크리트 관로용 가요성 지수재의 실험적 연구)

  • Kim, Tae-Hyup;Kim, Kwang-Soo;Hong, Sung-Nam;Park, Sun-Kyu;Cho, Cheong-Hwi;Lee, Jun-Koo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05a
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    • pp.90-93
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    • 2006
  • Buried pipeline is a indispensable factor of leading smoothly a society as a primary role. Recently, as a matter of convenience of construction and the economical purpose, the use of Precast Concrete products quickly increased. But there was various damage forms in a part of joint of Precast Concrete buried pipeline. The purpose of this study is to propose the new type of the flexible rubber packing material (EF) which could resist a permanent deformation of the ground or an earthquake and to investigate its safety together with effectiveness as conducting experiment and analysis.

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Photo Collage Rendering From a Single Image (한 장의 영상으로부터 포토 꼴라주 렌더링)

  • Ryoo, Seung-Taek;Park, Jin-Wan;Jho, Cheung-Woon
    • Journal of the Korea Computer Graphics Society
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    • v.11 no.3
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    • pp.23-27
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    • 2005
  • 시간과 공간을 서로 융합하려는 노력들이 현대 화가들의 작업을 통해 여러 가지 다양한 접근 방법이 시도되고 있다. 그중 포토 꼴라주(Photo Collage)를 이용한 작업들은 컴퓨터를 이용한 영상 처리 기술과 상반된 흐름을 가지고 있어 공학적 관점에서 매우 흥미롭다. 본 논문에서는 이러한 포토 꼴라주을 한 장의 사진을 이용하여 나타내고자 한다. 이를 위해 한 장의 사진을 사각 격자로 분할하고 분할된 각 셀들을 이차원 변환(크기변환, 이동, 회전)과 톤의 조절을 통해 구현하였다.

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An Experimental Studyon the Durability of Steel Field Reinforced Concrete Using Silica Fume (실리카흄을 혼입한 강섬유보강 콘크리트의 내구성에 관한 실험적연구)

  • 박승범;홍석주;조청휘;김부일
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.04a
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    • pp.285-291
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    • 1998
  • During recent years, the durability of concrete structures has been considered in concret practice and material research. To preserve the brittleness of concrete as well as energy absorption and impact resistance, amount of fiber usage has greatly increased in the field of public works. Ultra fine powder, silica fume, mixed into concrete, it reduce void of concrete structure. Especially, there's a great effect for strength improvement of concrete by initial pozzolanic reactions. For these reasons, if silica fume mixed into concrete, it decrease the total void by microfilter effect . Pozzolan reaction, between cement particle and silica powder, can elaborate the micro structure of matrix. And so, in this paper, we deal SFRC for the purpose of efficiently using of industrial by-products(silica fume). Also we performed the test for durability such as freeze-thaw resistance and accelerated carbonation of SFRC using silica fume.

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An Experimental Study on the Mechanical Properties of Fiber Reinforced Cement Composites Utilizing by-Products(II) (산업부산물을 활용한 섬유보강 시멘트 복합체의 역학적 특성에 관한 실험적 연구(II))

  • 박승범;윤의식;조청휘
    • Proceedings of the Korea Concrete Institute Conference
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    • 1993.10a
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    • pp.144-149
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    • 1993
  • The results of an experimental study on the manufacture and the mechanical properties of carbon fiber reinforced silica fume.cement composites and light weight fly ash.cement composites are presented in this paper. The CF reinforced silica fume.cement composites using silica fume early strength cement were prepared with Pan-derived or Pitch-derived CF, and Lt. Wt, fly ash.cement composites using fly ash, early strength cement, perlite and a small amount of foaming agent. As the test results show, the flexural strength, toughness and ductility of CF reinforced silica fume .cement composites were remarkably increased by fiber contents. Also, the manufacturing process technology of Lt. Wt. fly ash.cement composites was developed and its optimum mix proportions were proposed. And the compressive and flexural strength of the fly ash.cement composites by hot water cured were improved even more than by moist cured, but are decreased by increasing fly ash replaced ratio for cement.

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An Experimental Study on the Strength and Flexural Toughness of Steel Fiber Reinforced Concrete Using Fly Ash (플라이애쉬를 이용한 강섬유보강콘크리트의 강도 및 휨인성 특성에 관한 실험적 연구)

  • 박승범;조청휘;이봉춘;김정환
    • Proceedings of the Korea Concrete Institute Conference
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    • 1997.10a
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    • pp.345-350
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    • 1997
  • This paper describes an experimental study on the strength and flexural toughness of steel fiber reinforced concrete using fly ash. The fly ash contents were varied from 0% to 20% of cement weight to explore the effect of fly ash addition with steel fiber reinforced concrete. as the result, the tensile strength, flexural strength and flexural toughness were increased remarkably as steel fiber contents were increased to 2.0 vol.%. Also, the steel fiber reinforced concrete containing 10% fly ash developed the highest strength. In the same contents of steel fiber, the flexural toughness characteristics show excellent when fly ash contents were 10% and steel fiber contents were 1.5 vol%.

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Digital Halftoning with Maze Generation Algorithm (미로 생성 알고리즘을 이용한 디지털 하프토닝)

  • Jho, Cheung-Woon
    • Journal of Advanced Navigation Technology
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    • v.13 no.6
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    • pp.984-990
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    • 2009
  • Halftoning is very important image processing techniques in the digital printing industry which is a process of converting a continuous-tone image to bi-level tone image. In this paper we introduce a new digital halftoning method based on maze generation algorithm as a replacement algorithm of halftoning with space-filling curve. Previous error-diffusion methods based on space-filling curve suffer from regular pattern artifacts from uniform scan pattern. We use maze generation algorithm to remove this undesirable pattern of space-filling curve method.

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