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룰드 곡면으로 된 임펠러의 5축 황삭 가공에 관한 연구 (A Study on Five-Axis Roughing of Impeller with Ruled Surface)

  • 장동규;임기남;양균의
    • 한국정밀공학회지
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    • 제24권7호
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    • pp.60-68
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    • 2007
  • This paper presents an efficient 5-axis roughing method for centrifugal impeller. The efficient roughing is minimization of cutting time through minimizing tool tilting and rotating motions. To minimized cutting time, machining area is divided into sub-cutting regions using control points on hub curves and shroud curves of blade used to design and analyze centrifugal impeller. For sub-cutting regions, diameters of cutting tools are determined as big as possible. Then, tool paths are generated with the tilting axis and rotating axis of 5-axis machine limited and fixed, which can give more efficient machining speed and machining stability than the conventional methods. Experimental results show that the proposed method is more efficient than the conventional methods to mill with the only one cutting tool without dividing area and the previous methods to mill with simultaneous 5-axis processing with dividing area.

센서 정보를 이용한 객체 추적에 대한 연구 (A study of object trace using sensor information)

  • 김관중
    • 한국산학기술학회논문지
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    • 제14권4호
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    • pp.1921-1925
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    • 2013
  • 본 논문에서는 일정 지역에 내에 진입한 영상 객체에 대한 객체추적 방안을 제안한다. 인식된 객체에 대한 추적은 객체가 특정 지역에 진입할 경우 객체의 이동 패턴을 탐지하기 위해 추적을 수행할 수 있다. 이는 여러 애플리케이션에 적용될 수 있는 것으로 위험 지역 혹은 경계 지역에 비인가 객체의 침입이나 특정 객체의 행동 패턴을 확인하기 위하여 객체의 추적 및 탐색을 수행하는 것이다.

건축기초에서의 매입말뚝 설계기준 및 사례 (Review of Design Guide and Case Study on Bored Prefabricated Piling Method in Architectural Building Foundation)

  • 이원제
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2008년도 추계 학술발표회
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    • pp.549-558
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    • 2008
  • Well known and widely used in urban area and limited installation condition, a low noise and vibration piling method which has being called Bored Prefabricated Piling Method was reviewed in terms of design guide, and introduced a few case as well. Among the areas being applied of that method, a structural guide of architectural foundation was reviewed and compared to civil engineering foundation area to provide wider information for the foundation engineers. With introducing a few case application including pile load testing review especially dynamic testing in normal building foundation work, engineers may have a useful information on the design and construction of the piling method even different engineering area. It may also make enhancement a view of foundation engineering knowledge to various pile foundation area.

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The Birth and Development of High-Rise Buildings in Japan: Focusing on the Historical Development of Height and Floor Area Ratio Regulations

  • Akihiko Osawa
    • 국제초고층학회논문집
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    • 제12권3호
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    • pp.195-201
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    • 2023
  • This paper reviews the history of the birth and development of the skyscraper in Japan, mainly from the perspective of the legal system, and presents the following points: 1) After 1919, building height was limited to 31 m or less, which continued after the war and defined the skyline of Japan's major cities; 2) The 31-meter height limit became a problem during rapid economic growth. With the development of tall building construction technology, the height limit was eliminated, and skyscrapers were born in Japan in the 1960s; 3) Later, the number of skyscrapers increased more rapidly in the post-bubble period after the collapse of the bubble economy in the 2000s than in the boom years of the 1980s, when the floor-area ratio was relaxed for economic uplift and urban renewal. The number of skyscrapers increased rapidly against the backdrop of the deregulation of the floor-area ratio.

한강 하구역의 염분 분포 및 생태환경특성 (Salinity Distribution and Ecological Environment of Han River Estuary)

  • 박경수
    • 한국습지학회지
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    • 제6권1호
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    • pp.149-166
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    • 2004
  • 한강 하구의 염분 및 생태 환경에 관한 연구를 위하여 기존에 발표된 논문과 국립수산과학원의 국가해양환경측정망 자료를 이용하여 한강 하구의 염분 분포 특성을 구명하였으며, 염분과 연관하여 동식물플랑크톤, 저서생물 및 어류플랑크톤의 분포를 논의하였다. 염분의 시공간적 분포를 고려할 때 인천북항 주변 해역은 계절에 무관하게 연중 한강 유입수의 직접적인 영향을 받고 있으며, 담수 유입량이 많은 하계에는 팔미도 해역까지 담수 영향권이 확대되었다. 반면 해수의 직접적인 영향을 받는 상한선은 한강 본류인 경기도 김포시 고촌면 신곡리의 신곡수중보에 이르며, 해침이 상시적으로 발생하는 수역은 이보다 더 하류인 경기도 김포시 하성면 전류리로 판단된다. 동식물플랑크톤의 분포는 담수 및 해수 지역에서 혼재되어 분포하며, 일반적으로 염분의 분포 범위보다 훨씬 광범위한 분포를 보였다. 그러나 기수성 어류플랑크톤은 매우 제한된 수역에 분포하는 반면, 성어는 그 분포범위가 담수에서 해수에 이르는 광범위한 분포를 보였다. 경험적 분석에 의한 한강하구 환경의 문제점은 1)한강 하구 및 유수지역의 개발 압력에 따른 환경 파괴, 2)갯벌 매립에 의한 조간대 상실, 3)군사용 철책에 의한 육수전이환경(陸水轉移環境)의 생태적 단절이 매우 심각하였다.

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비트 - 플레인 영상을 이용한 프랙탈 부호화 기법 (Fractal Coding Method using Bit - plane Image)

  • 김정일;이광배;김현욱
    • 한국정보처리학회논문지
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    • 제5권4호
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    • pp.1057-1065
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    • 1998
  • 본 논문에서는 탐색영역 제한방식과 스케일링 방식을 이용하여 프랙탈 영상 부호화시에 걸리는 시간을 줄이는 새로운 프랙탈 영상 부호화 알로리즘을 제안한다. 먼저, 원영상을 스케일링 방식을 이용해 1/2과 1/4의 크기를 가지는 영상으로 축소한다. 이어서, 1/2 크기를 가지는 레인지 블록들 중에 1/4의 크기를 가지는 도메인 블록과 가장 유사한 블록을 탐색영역 제한방식을 이용해 검색하게 된다. 이와같이 검색된 블록이 부호화에 사용된다. 또한, 비트 플래인 영상을 이용하여 압출율을 향상시키기 위한 알고리즘도 제안한다. 실험 결과, 제안된 알고리즘은 Jacquin의 방법에 비해 복원돈 영상의 화질은 약간 떨어졌으나, 압축율이 향상되고 부호화 시간을 대폭 감소시킬 수 있었다.

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서울메트로 접지설비 표준화 방안 연구 (A Study on the Unification of the Grounding System of SeoulMetro)

  • 김균식;박한용;백유호
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2007년도 춘계학술대회 논문집
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    • pp.1027-1036
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    • 2007
  • Since the opening of the Seoul Metro in 1974, the electric railway passengers have been increased rapidly and as the advanced equipments(OC,PSD) were introduced, additional power facilities were built in a limited area for the comfortable transportation environment. Present grounding system were built according to old Electric equipment standards and all the electric signal, communication and electronic equipments were built only for the purposes of protecting building structure, people and electronic equipments. Grounding system which was additionally built in the limited area caused problems with the building structure and it caused secondary damages when earth fault happens. One of the problems is grounding system of the building structure; grounding system does not work properly since grounding equipments are not separated from each other. So, existing grounding system needs to be improved and unified grounding system in the building should be established. The purposed of this study is to analyze all the grounding systems that had been built in different year and to establish unified grounding system of Seoul Metro.

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국지규모 풍력에너지 평가를 위한 기상 관측 자료의 영향 반경 특성 (Characteristics of Efficient Radius of Meteorological Observation Data to Estimate Regional Wind Energy)

  • 이순환;김민정;이화운
    • 한국대기환경학회지
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    • 제23권5호
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    • pp.585-595
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    • 2007
  • Representative impacts and effectiveness of surface meteorological observation data assimilation were examined in order to use wind resources estimation around southern coastal area of the Korean Peninsula. The data used in study are observational wind and temperature data at 5 and 41 sites of Regional Meteorological Offices and Automatical Weather Systems, respectively. Observation wind speed data tends to show small effective radius with limited area. Especially assimilation impacts of data observed at peninsula type sites like Yeosu play only around the inside of the peninsula. This limited effective radius for wind speed is caused by the strong correlation between topography and wind speed. And the efficient radius for surface air temperature is larger than that of wind. Data assimilation for observational air temperature is useful to increase the accuracy of wind energy estimation. However assimilation of wind data requires special care in its application due to high sensitivity of topographical complexity.

한방 의료행위의 개념과 그 한계 - 법령과 판례를 중심으로 - (The Concept of Practice of Korean Medicine and the Limitations - Focusing on Legislations and Precedents -)

  • 권순조;엄석기
    • 한국의사학회지
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    • 제28권1호
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    • pp.121-133
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    • 2015
  • Objectives : The purpose of this study is to suggest how to interpret the 'practice of Korean Medicine', differentiating it from 'medical practice'. Methods : I analyze the legislations and precedents regarding the practice of Korean Medicine. Results : The Korean Medicine and Pharmaceutics Promotion Act defines 'practice of Korean Medicine' and it clearly differentiates it from the definition of 'medical practice'. However, the scope of this definition is somewhat restricting and it can violate doctors of Korean Medicine's right to equality and their academic freedom. Thus, the application of this definition of the 'practice of Korean Medicine' should be limited to the field of research and development. Meanwhile, criteria of distinguishing 'practice of Korean Medicine' from 'medical practice', which used to make a sharp distinction between Medicine and Korean Medicine by rigorously applying their academic standards, are now focusing more on protecting and improving health of the people. Discussions & Conclusions : I suppose that the distinction between the 'practice of Korean Medicine' and 'medical practice' will be more focused on public health rather than the academic stance of those two medical fields. Meanwhile, in accordance with dualistic medical system, the mutual usage of medical equipment in the area of 'treatment' should be limited while it should be allowed in the area of 'diagnosis' if it satisfies requirements suggested by the Constitutional Court.

영상정보의 저장 공간 관리를 위한 동적/정적 객체 분리 및 시각암호화 메커니즘 (Dynamic / Static Object Segmentation and Visual Encryption Mechanism for Storage Space Management of Image Information)

  • 김진수;박남제
    • 한국멀티미디어학회논문지
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    • 제22권10호
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    • pp.1199-1207
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    • 2019
  • Video surveillance data, which is used for preemptive or post-emptive action against any event or accident, is required for monitoring the location, but is reducing the capacity of the image data by removing intervals for cost reduction and system persistence. Such a video surveillance system is fixed in a certain position and monitors the area only within a limited angle, or monitors only the fixed area without changing the angle. At this time, the video surveillance system that is monitored only within a limited angle shows that the variation object such as the floating population shows different status in the image, and the background of the image maintains a generally constant appearance. The static objects in the image do not need to be stored in all the images, unlike the dynamic objects that must be continuously shot, and occupy a storage space other than the necessary ones. In this paper, we propose a mechanism to analyze the image, store only the small size image for the fixed background, and store it as image data only for variable objects.