• 제목/요약/키워드: space-time correlation

검색결과 431건 처리시간 0.033초

논문 : Two Color PIV 기법을 이용한 램제트엔진 연소기 특성에 대한 연구 (Papers : A Study on the Characteristics of the Ramjet Engine Combustor using a Two Color PIV Technique)

  • 안규복;윤영빈;정인석;허환일
    • 한국항공우주학회지
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    • 제30권1호
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    • pp.95-104
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    • 2002
  • 램제트 연소기내의 복잡한 고속 유동의 가시화를 위해 two color PIV 기법을 개발하였다. Two color PIV 기법은 두 레이저 빔 사이의 시간 간격을 ㎲ 단위 이하로 조절할 수 있어 고속 유동에의 적용이 가능할 뿐 아니라, 기록된 필름에서의 색분리를 통하여 방향성의 분제를 해결할 수 있으며, 거의 완벽한 cross-correlation이 가능하여 signal-to-noise ratio가 상당히 증가한다는 장점을 갖게 된다. 본 연구에서는 램제트 엔진에 대한 기초 연구로서 양쪽 대칭의 공기 흡입구를 갖는 2차원 형태의 램제트 엔진 연소기를 제작하였고, two color PIV 기법을 이용하여 실험을 수행하였다. 흡입공기의 연소실내 유입각도와 연소시내 도움 위치에 따른 연소실 형상을 바꾸어가며 재순환 영역과 유입공기의 혼합과 같은 유동 특성을 분석하였다. 유입각도는 전체 유동장 뿐 아니라 재순환 영역의 크기와 재순환 영역내의 공기질량비에 상당한 영향을 끼치나, 도움 높이는 재순환 영역에 큰 영향을 주지 않는다는 것을 알 수 있었다.

A Heuristic Method of In-situ Drought Using Mass Media Information

  • Lee, Jiwan;Kim, Seong-Joon
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2020년도 학술발표회
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    • pp.168-168
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    • 2020
  • This study is to evaluate the drought-related bigdata characteristics published from South Korean by developing crawler. The 5 years (2013 ~ 2017) drought-related posted articles were collected from Korean internet search engine 'NAVER' which contains 13 main and 81 local daily newspapers. During the 5 years period, total 40,219 news articles including 'drought' word were found using crawler. To filter the homonyms liken drought to soccer goal drought in sports, money drought economics, and policy drought in politics often used in South Korea, the quality control was processed and 47.8 % articles were filtered. After, the 20,999 (52.2 %) drought news articles of this study were classified into four categories of water deficit (WD), water security and support (WSS), economic damage and impact (EDI), and environmental and sanitation impact (ESI) with 27, 15, 13, and 18 drought-related keywords in each category. The WD, WSS, EDI, and ESI occupied 41.4 %, 34.5 %, 14.8 %, and 9.3 % respectively. The drought articles were mostly posted in June 2015 and June 2017 with 22.7 % (15,097) and 15.9 % (10,619) respectively. The drought news articles were spatiotemporally compared with SPI (Standardized Precipitation Index) and RDI (Reservoir Drought Index) were calculated. They were classified into administration boundaries of 8 main cities and 9 provinces in South Korea because the drought response works based on local government unit. The space-time clustering between news articles (WD, WSS, EDI, and ESI) and indices (SPI and RDI) were tried how much they have correlation each other. The spatiotemporal clusters detection was applied using SaTScan software (Kulldorff, 2015). The retrospective and prospective cluster analyses were conducted for past and present time to understand how much they are intensive in clusters. The news articles of WD, WSS and EDI had strong clusters in provinces, and ESI in cities.

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레지오 에밀리아의 교육 환경 이론과 심리치유 공간 개념 - 어린이 유치원 시설을 중심으로 (A Study on Educational environment Theory of Reggio Emilia and Space Concept for Healing - Focused on the Childcare Facilities)

  • 변지혜;김광호
    • 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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    • 제21권2호
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    • pp.25-33
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    • 2015
  • Purpose: This study is to suggest a direction for comprehensive planning of educational environment in which children's cognitive development and emotional needs are achieved in childcare facilities. The importance of educational environment in childcare facilities has increased since it was discovered that high quality educational environment can not be guaranteed in current childcare facilities while the number of women participating in labor force, hence the number of children spending most of their time in these facilities is rapidly increasing. Methods: Correlation analysis on Reggio Emilia Approach to education environment and Max Luscher's psychological healing theory, and case study. Results: The result of the correlation analysis, the 4 key elements of educational environment and the 4 emotional status have significant relationship. Based on the elements of educational environment in Reggio Emilia Approach, case studies were pursued in 3 different childcare facilities in Korea. Implications: Evaluation of these case studies addresses the important elements to be considered in comprehensive planning of the educational environment in childcare facilities.

Magnetic Resonance Imaging and Pathologic Correlation of Cerebral Fat Embolism using Oleic Acid

  • Park, Byung-Rae
    • 대한의생명과학회지
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    • 제10권2호
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    • pp.115-120
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    • 2004
  • To investigate the correlation between the magnetic resonance imaging (MRI) of cerebral fat embolism that is induced by injecting oleic acid into 10 cats, and a pathologic diagnosis. Using a microcatheter, 30 ${mu}ell$ of oleic acid was injected into the internal carotid artery of 10 cats. MR T2-weighted image (T2WI), diffusion-weighted image (DWI) and Gadolinium-enhanced T1-weighted image (Gd-enhanced T1WI) were obtained after 30 minutes and 2 hours of embolization. After 30 minutes of the embolization, lesions of very high signal intensity were detected by T2WI in 6 cats, and of slightly high signal intensity in 2 cats; in the remaining 2 cats, signal intensity was normal. DWI showed lesions of very high intensity in 9 cats and of slightly high intensity in one cat. According to the findings of light microscopic examination, infarcted lesions mainly involved the gray matter, but also some white matter. A magnetic resonance imaging diagnosis for cerebral fat embolism that was induced by oleic acid through the internal carotid artery in cats showed high signal intensity on the T2WI and the DWI within an initial 2 hours, and with a well enhancement on the Gd-enhanced T1WI. Considering cellular edema, cerebrovascular injury and extracellular space widening, we assumed pathologically that cytotoxic and vasogenic edema exists at the same time.

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지구통계학을 활용한 지반정보 가시화 기법 개발 (The Development of Technique for the Visualization of Geological Information Using Geostatistics)

  • 송명규;김진하;황제돈;김승렬
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2001년도 봄 학술발표회 논문집
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    • pp.501-508
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    • 2001
  • A graph or topographic map can often convey larger amounts of information in a shorter time than ordinary text-based methods. To visualize information precisely it is necessary to collect all the geological information at design stage, but actually it is almost impossible to bore or explore the entire area to gather the required data. So, tunnel engineers have to rely on the judgement of expert from the limited number of the results of exploration and experiment. In this study, several programs are developed to handle the results of geological investigation with various data processing techniques. The results of the typical case study are also presented. For the electric survey, eleven points are chosen at the valley to measure the resistivity using Schlumberger array. The measured data are interpolated in 3-dimensional space by kriging and the distribution of resistivity are visualized to find weak or fractured zone. The correlation length appears to be around 5 to 20 meter in depth. Regression analyses were performed to find a correlation length. No nugget effect is assumed, and the topographic map, geologic formation, fault zone, joint geometry and the distribution of resistivity are successfully visualized by using the proposed technique.

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e-learning의 학습효과에 영향을 미치는 주요요인에 관한 연구 (A Study on Factors Associated with Effect of e-Learning)

  • 류근호;김병철
    • 한국콘텐츠학회논문지
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    • 제5권2호
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    • pp.53-60
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    • 2005
  • e-teaming은 시간적, 공간적 제약으로부터의 자유스러움으로 인해 전통적 교육의 보조 도구로써, 또는 전통적 교육을 대신해서 이미 많은 부분에서 e-learning이 이루어지고 있다. 본 논문은 e-learning의 중요성과 그것이 차지하는 비중이 상당히 커져 있는 시점에서 e-learning 교육 경험자들이 인터넷 기반 e-learning의 학습효과를 전통적 교육에 비해 어느 정도로 인식하고 있는지에 대한 조사를 수행하였다. 또한 인터넷 기반 e-learning의 학습효과에 대한 요인변수를 도출하고, 인터넷 기반e-loaming의 학습효과로 인식하는 정도가 어떠한 요인에 의해 얼마만큼의 영향을 받고 있는지를 파악하여 제시하였다.

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언덕이 있는 하상유동 계측을 통한 PIV기법의 수력학적 적용연구 (Application of PIV in the Flow Field Over a Fixed Dune Bed)

  • 현범수
    • 한국해양환경ㆍ에너지학회지
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    • 제5권3호
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    • pp.10-15
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    • 2002
  • 반복적으로 나타나는 고정된 이차원 모래언덕에 의하여 생성되는 난류유동장을 해석하기 위하여 PIV 기법을 적용하였다. PIV 기법의 사정을 위하여 LDV 실험자료와 결과를 비교하였는데 유동박리 및 큰 전단유동 영역에까지 좋은 결과를 보여주었다 레이저 시트로 조사된 이차원 단면의 흐름을 이미징 테크닉으로 해석하는 PIV 방법이 갖는 고유의 단점들을 완전히 해결하지는 못하였으나, 전체적으로 LDV 결과와 매우 잘 일치하고 있었으며 특히 Two-point correlation 이나 Quadrant analysis와 같이 고차항까지를 추적할 수 있었다 특히 기존의 일점계측법으로는 해석이 불가능한 순간유동장의 가시화 및 정량화가 가능하였으며 Time-series로 변환시킨 PIV 데이터의 신뢰성도 확인이 가능하였다. 추후 토사이동과 같은 복잡한 유동해석에도 본 기법을 그대로 활용할 수 있으리라 기대한다.

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합성난류경계층이 벽면에서의 변동압력에 미치는 영향 (Effects of Synthetic Turbulent Boundary Layer on Fluctuating Pressure on the Wall)

  • 이영우;이동섭;신구균;홍진숙;임희창
    • 한국가시화정보학회지
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    • 제19권3호
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    • pp.92-98
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    • 2021
  • Large Eddy Simulation (LES) has been popularly applied and used in the last several decades to simulate turbulent boundary layer in the numerical domain. A fully developed turbulent boundary layer has also been applied to predict the complicated wake flow behind bluff bodies. In this study we aimed to generate an artificial turbulent boundary layer, which is based on an exponential correlation function, and generates a series of realistic three-dimensional velocity data in two-dimensional inlet section which are correlated both in space and in time. The results suggest its excellent capability for high Reynolds number flows. To make an effective generation, a hexahedral mesh has been used and Cholesky decomposition was applied to possess suitable turbulent statistics such as the randomness and correlation of turbulent flow. As a result, the flow characteristics in the domain and fluctuating pressure near the wall are very close to those of fully developed turbulent boundary layers.

호텔 식음료공간의 디자인과정에서 영업성 검토에 관한 연구 - N 호텔의 사례를 중심으로- (Interior Design Process for Food & Beverage Facilities of a City Hotel)

  • 김정근
    • 한국실내디자인학회논문집
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    • 제1호
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    • pp.39-45
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    • 1992
  • Today the design is recognized as indispensible part in business activities and it is demanded as one of the management strategies. since the ultimate goal of a hotel lines in the pursuit of profit, it is important that the design of a hotel faithfuly reflects the demands of management at the time of its construction planning. Furthermore, hotel planning undergoes a complicated design phases on a large scale, thus, utilization of a design process that accomodates retional approaches scientific and structural design activities, which will further reduce errors in design steps and pave a way for effective attainment of the target. Especially the management and designers review and confirm the design in relation to the strategic manegiable objective sat the early basic stage. The baseline set here will serve as a direction for the detailed design. In this context, this thesis formulates a reference baseline in dividing the space in view of the overall profitability and is based upon a survey conducted on the correlation between the operation of food and beverage section and the space. First, downtown hotels now take on the role of a public facility to a great extent and the number of Koreans who visit the autxiliary facilities of hotel increases. Second, recently revenue from a food and beverage section is in downtown and the trend is especially obrious at western restaurant, buffet and bar. This necessitates the reevaluation of the business space allocation. Third, sales promotion plan includes diversification, dessection and scaling down of the food and beverage section areas, Fourth, a proper number of seats must be determined in regard to the average area of one seat shown in the survey. Fifth, dense seat arrangement would entail a curtailment rather than a hike in revenue. Sixth, the installation of private dining room is on the rise and in particular, in Japanese and Chinese restaurants. Seventh, business space with declined revenue tends to induce the integration of similar businesses.

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프로이트의 무의식 관점으로 본 공간 속 오브제 의미에 관한 연구 - 2000년 이후의 필립 스탁 작품을 중심으로 - (A Study on the Meaning of object in Space from the Viewpoint of the Unconscious of Freud - Focusing on works by Philippe Starck after 2000 -)

  • 박유미;이찬
    • 한국실내디자인학회논문집
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    • 제17권2호
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    • pp.130-139
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    • 2008
  • We have attached importance to the values of spirit and immateriality. As the age of modernism of rationality ended, human being began to emphasize spiritual and immaterial while accepting multiplicity and diversification in the whole areas of society and culture. Hence interests have increased in another side of human spirit that was oppressed by rational, analytic, reasonable and scientific thinking, which has expanded the inner world of human being to the world of the unconscious. According to these paradigm changes, steady efforts to improve our lives better both materially and spiritually have been made in the areas of art and design. Therefore, the current study aims to examine the meaning of object expressed in space from the viewpoint of the unconscious, focusing on works of designer Philippe Starck after 2000 in which unique, preferential and liking characteristics are expressed well. Philippe Starck is a designer who connects design with our daily lives and formalizes it with creative ideas. Also the study theoretically explored the theory of the unconscious, a concept of Freudianism, based on 'Meaning of Dreams' of Freud, and explained the expressional characteristics and meaning of unconscious desire through his works by putting object in Philippe Starck's space. It aims to grope for the meaning of object as another possibility that can function as a spatial ruling element by analyzing object through expanding the extent of correlation and interpretation between human containing spiritual things and object which is the recognition subject in space of the present time, not a mere concept as substance like in the past, and expression of Starck's unconscious desire based on unconscious theory.