• Title/Summary/Keyword: constancy

검색결과 206건 처리시간 0.025초

한반도 바람자원의 시공간적 분포 (Spatial and temporal distribution of Wind Resources over Korea)

  • 김도우;변희룡
    • 대기
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    • 제18권3호
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    • pp.171-182
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    • 2008
  • In this study, we analyzed the spatial and temporal distribution of wind resources over Korea based on hourly observational data recorded over a period of 5 years from 457 stations belonging to Korea Meteorological Administration (KMA). The surface and 850 hPa wind data obtained from the Korea Local Analysis and Prediction System (KLAPS) and the Regional Data Assimilation and Prediction System (RDAPS) over a period of 1 year are used as supplementary data sources. Wind speed is generally high over seashores, mountains, and islands. In 62 (13.5%) stations, mean wind speeds for 5 years are greater than $3ms^{-1}$. The effects of seasonal wind, land-sea breeze, and mountain-valley winds on wind resources over Korea are evaluated as follows: First, wind is weak during summer, particularly over the Sobaek Mountains. However, over the coastal region of the Gyeongnam-province, strong southwesterly winds are observed during summer owing to monsoon currents. Second, the wind speed decreases during night-time, particularly over the west coast, where the direction of the land breeze is opposite to that of the large-scale westerlies. Third, winds are not always strong over seashores and highly elevated areas. The wind speed is weaker over the seashore of the Gyeonggi-province than over the other seashores. High wind speed has been observed only at 5 stations out of the 22 high-altitude stations. Detailed information on the wind resources conditions at the 21 stations (15 inland stations and 6 island stations) with high wind speed in Korea, such as the mean wind speed, frequency of wind speed available (WSA) for electricity generation, shape and scale parameters of Weibull distribution, constancy of wind direction, and wind power density (WPD), have also been provided. Among total stations in Korea, the best possible wind resources for electricity generation are available at Gosan in Jeju Island (mean wind speed: $7.77ms^{-1}$, WSA: 92.6%, WPD: $683.9Wm^{-2}$) and at Mt. Gudeok in Busan (mean wind speed: $5.66ms^{-1}$, WSA: 91.0%, WPD: $215.7Wm^{-2}$).

peA 와 KNN를 이용한 3차원 물체인식 (Three Dimensional Object Recognition using PCA and KNN)

  • 이기준
    • 한국콘텐츠학회논문지
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    • 제9권8호
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    • pp.57-63
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    • 2009
  • 기존의 주성분 분석을 이용한 물체 인식 기술은 모델 영상내의 각각의 물체의 대표 값을 만든 후에 실험 영상을 물체 공간에 투영 시켜서 나온 성분과 대표 값의 거리를 비교하여 인식하게 된다. 그러나 단순히 기존의 방법인 point to point 방식인 단순 거리 계산은 오차가 많기 때문에 본 논문에서는 개선된 Class to Class 방식인 k-Nearest Neighbor을 이용하여 몇 개의 연속적인 입력영상에 대해 각 각의 모델영상들을 인식의 단위로 이용하였다. 또한, 물체 인식을 하는데 있어 본 논문에서 제안한 주성분 분석법은 물체 영상 자체를 계산하여 인식하는 게 아니라 물체 영상 공간이라는 고유 공간을 구성한 후에 단지 기여도가 큰 5개의 벡터로만 인식을 수행하기 때문에 자원 축소의 효과까지 얻을 수 있었다.

THE ATTITUDE STABILITY ANALYSIS OF A RIGID BODY WITH MULTI-ELASTIC APPENDAGES AND MULTI-LIQUID-FILLED CAVITIES USING THE CHETAEV METHOD

  • Kuang, Jin-Lu;Kim, Byung-Jin;Lee, Hyun-Woo;Sung, Dan-Keun
    • Journal of Astronomy and Space Sciences
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    • 제15권1호
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    • pp.209-220
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    • 1998
  • The stability problem of steady motion of a rigid body with multi-elastic appendages and multi-liquid-filled cavities, in the presence of no external forces or torque, is considered in this paper. The flexible appendages are modeled as the clamped -free-free-free rectangular plates, or/and as the discrete mass- spring sub-system. The motion of liquid in every single ellipsoidal cavity is modeled as the uniform vortex motion with a finite number of degrees of freedom. Assuming that stationary holonomic constraints imposed on the body allow its rotation about a spatially fixed axis, the equation of motion for such a systematic configuration can be very complex. It consists of a set of ordinary differential equations for the motion of the rigid body, the uniform rotation of the contained liquids, the motion of discrete elastic parts, and a set of partial differential equations for the elastic appendages supplemented by appropriate initial and boundary conditions. In addition, for such a hybrid system, under suitable assumptions, their equations of motion have four types of first integrals, i.e., energy and area, Helmholtz' constancy of liquid - vortexes, and the constant of the Poisson equation of motion. Chetaev's effective method for constructing Liapunov functions in the form of a set of first integrals of the equations of the perturbed motion is employed to investigate the sufficient stability conditions of steady motions of the complete system in the sense of Liapunov, i.e., with respect to the variables determining the motion of the solid body and to some quantities which define integrally the motion of flexible appendages. These sufficient conditions take into account the vortexes of the contained liquids, the vibration of the flexible components, and coupling among the liquid-elasticity solid.

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Potential and Significance of Ammonium Production from Helicobacter pylori

  • KI, Mi-Ran;Yun, Soon-Kyu;Choi, Kyung-Min;Hwang, Se-Young
    • Journal of Microbiology and Biotechnology
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    • 제13권5호
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    • pp.673-679
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    • 2003
  • Glutamine and urea, abundant in body fluids or plasma, yield net ammonium ions upon hydrolysis by ${\gamma}-glutamyl$ transpeptidase (${\gamma}-GTP$) and urease, respectively, and these two enzymes are largely produced from Helicobacter pylori. To investigate bacterial potential of ammonium production, we first quantified those in whole-cell systems and found that the relative ratio of their amounts varied greatly, especially with pH values and the cell's aging. During the H. pylori cultivation, the ratio appeared to be inversely proportional to each other, showing a progressive increase of the ${\gamma}-GTP$ with decreasing of the urease. Under the urease-defective conditions due to low pH or coccoids, the bacterial cells still possessed a considerable amount of ${\gamma}-GTP$, which was found exclusively in the external compartment, therefore, the cell's ammonium production was found to be solely dependent upon glutamine, and the external ammonium concentration was constant without any contribution of urea concentration. Such ammonium constancy would definitely have an adverse effect on the host, because of its absolute requirement for vacuolar degeneration by H. pylori VacA, maximized at approximately 10 mM $NH_4Cl$. It was also found that, by using the metal-saturated membrane vesicles, ammonium ions were likely to be involved in the pH-dependent cation-flux across the H. pylori membrane, where the role of ${\gamma}-GTP$ in ammonium homeostasis around cells was suggested, especially under the hostile conditions against H. pylori.

비전기반 지능형 자동차를 위한 도로 주행 영상 개선 방법 (Road Image Enhancement Method for Vision-based Intelligent Vehicle)

  • 김승규;박대용;최영우
    • 인지과학
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    • 제25권1호
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    • pp.51-71
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    • 2014
  • 본 논문에서는 도로 주행에서 취득한 영상을 개선하는 방법을 제안한다. 일반적인 도로주행 영상은 다양한 조명 환경과 날씨 상태로 인하여 선명하지 못한 영상이 취득되기도 한다. 특히 역광이나 야간에는 품질이 좋은 선명한 영상을 얻기가 더욱 어려우며, 이는 비전기반 지능형 자동차 기술의 응용에 많은 어려움을 준다. 인간의 시각 인지방법은 여러 가지조명 조건을 고려하여 색을 지각한다. 하지만 기존의 영상 개선 방법들은 광원의 위치와 광도, 기하학적 관계를 고려하지 않기 때문에 완벽한 결과를 얻기가 어려우며, 오히려 영상의 질이 떨어지는 경우도 발생한다. 본 논문에서는 이러한 문제점을 해결하기 위해서 1) 주어진 입력 영상의 전처리 과정을 수행한 후, 2) 선명도를 추정하여 색채의 대비를 평가하고, 3) 과대 및 과소평가 결과를 전처리된 영상과 혼합하여 사람이 지각하는 색상과 같이 개선된 영상을 얻는 효과적인 방법을 제안한다. 본 논문에서 제안하는 방법은 시각적으로 개선된 결과를 보여줄 뿐만 아니라 비전기반 지능형 자동차 기술의 한 응용분야인 교통표지판 검출의 전처리 과정으로 적용되어 성능이 향상됨을 확인할 수 있었다.

페이퍼 에레크트로포레시스에 關한 硏究 (제1보) 계란단백의 移動度에 關하여 (Studies on the Paper Electrophoresis, I On the Mobility of Egg Albumin(Ovalbumin))

  • 장세헌;김시중
    • 대한화학회지
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    • 제4권1호
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    • pp.1-6
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    • 1957
  • The mobilities and the electrophoretic phenomena of human serum albumin, and of horse serum albumin, etc., on paper were reported, but there is no information about the mobility and the electrophoretic phenomena of ovalbumin. In this study they are determined and considered at various time durations. The mean value of this mobility is compared with the value determined by the electrophoresis in solution. Also, the mobilities of the electroendosmotic flow, which affect on the mobility seriously, are determined at various time durations. Apparatus and method used, are a closed system type and a method with electrode vessels. It is concluded that: 1) The mobilities of ovalbumin have the nearly constant mobilities at six and eight hours of time durations, but it decreases at ten hours of long time duration. Their mean value is (0.243 ${\pm}$ 0.003)cm./hr./v./cm. toward anode at pH 8.0. 2) Under these experimental conditions, ovalbumin cannot be separated into three fractions (A1, A2, A3) on paper. 3) Most of the factors, which affect on the mobility, are fixed by the initial experimental conditions, but the electroendosmotic flow due to the characteristic capillarity of paper is measured. Then, the mean value of its mobilities shows the good constancy, and the value is (0.073 ${\pm}$ 0.0003)cm/hr./v./cm. toward cathode at pH 8.0. 4) By the above facts, if the same paper and the same experimental conditions are chosen, it may be preferred to determine the mobility of the electroendosmotic flow once time, even when many observations are required.

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조도 변화를 고려한 동영상 색 유동성 저감 알고리즘 (Temporal Color Rolling Suppression Algorithm Considering Time-varying Illuminant)

  • 오현묵;강문기
    • 대한전자공학회논문지SP
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    • 제48권5호
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    • pp.55-62
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    • 2011
  • 본 논문은 조도 변화에 의해 동영상 시퀀스에서 발생하는 주기적인 색상 및 밝기 변화를 저감하기 위한 알고리즘을 제안한다. 밝기 변화가 주기적으로 일어나는 광원 환경에서 동영상을 촬영하는 경우, 노출 시간이 짧아짐에 따라 색상 및 밝기가 주기적으로 변하는 색 유동성 현상, 즉 컬러 롤링 현상(color rolling phenomenon)이 발생한다. 색 유동성 현상이 발생하는 경우 화이트 밸런스 알고리즘을 적용함으로써 개별 프레임의 색상을 보정할 수 있지만, 프레임 간에 발생하는 밝기 차이를 고려하지 않기 때문에 동영상의 밝기가 주기적으로 변하는 문제가 남게 된다. 제안하는 방법에서는 프레임 간에 발생하는 밝기 변화를 추정함으로써 색 유동성 현상으로 인해 나타나는 밝기 및 색상 변화를 보정하는 알고리즘을 제안한다. 이 때, 움직이는 물체에 의해 발생하는 밝기 변화 추정 에러를 줄이기 위해 움직임 검출(motion detection) 방법에 기반하여 색 유동성에 의한 밝기 변화만을 선택적으로 검출하여 보상한다. 또한 이전 밝기 정보를 이용하여 색 유동성에 의한 밝기 변화량을 예측함으로써 실시간 영상 처리에 적합하도록 하였다. 실험 결과를 통해 제안하는 방법을 사용하는 경우 조도 변화에 의한 밝기 변화를 보상함으로써 동영상의 프레임 간 밝기 및 색상의 항상성을 유지하는 것을 확인할 수 있다.

서천지방의 지상풍 연변화에 관하여 (On the Annual Change of Surface Wind at Seocheon, Korea)

  • 문승의;김백조
    • 한국환경과학회지
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    • 제7권3호
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    • pp.375-382
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    • 1998
  • 우리나라 서해안에 위치한 서천지방 연안에 10m기상 관측탑을 설치하여 1년동안 관측한 바람자료를 사용하여 지상풍의 기초 통계량, 정상도 및 월별 정규성 검정을 조사하였다. 해륙풍과 같은 국지순환의 영향으로 8훨과 9월에 조차 북풍계열이 나타났다. 두 바람성분간의 상관계수는 6월과 9월사이, 10월과 4월사이 기간동안에 각각 양((+)과 음(-)의 값으로 나타났다. 바람의 정상도는 겨울철에 높게.여름철에 낮게 나타났다. 샘플링 시간이 증가함에 따라 S값의 modal이 감소하고 최대 발생빈도값이 5값의 낮은 영역으로의 이동이 뚜렷하게 나타났다. 패도와 초가 첨도에 기초한 월별 정규성 검정으걸 부터 바람의 동서성분은 봄철에. 남북성분은 늦여름과 초가을에 각각 정규분포를 가짐을 알 수 있었다.

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아시안 룩의 탈중심화 현상과 그 기법에 대한 연구 (An Investigation of the Phenomenon of the Decentralization of the Asian Look and its Method)

  • 서봉하
    • 복식
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    • 제61권2호
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    • pp.20-31
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    • 2011
  • Decentralization is an effort to liberalize people from its character of neutralizing or restraining people while indwelling in the previous thought system. Decentralization in fashion is one of the phenomenon of post-modernism fashion, and it is closely related to de-culturalism, crossover, abolition of rank, and etc, and it is in line with Asian look which includes orientalism fashion. The study intends to consider the Phenomenon of Decentralization of Asian Look and its Method depicted in the western fashion. The study focuses on documentary data, and the it is held with the basis of Asian look shown in western fashion. If ideology which influenced the formation of folk costume of Asia, Asian look is the dissolution of such ideology, and post-modern amusement is substituting it. The most conspicuous characteristic of decentralization phenomena of Asian look is pastiche which is a combination and reallocation of external style of many cultural zones and many folk costumes, and it shows mutual irrelevance, and it is a neutral imitation which has internal meaning and humor disappeared. Also, Asian look shows characteristics of parody and irony, which are reversal characteristics of aesthetic value which is expressed through methods of addition, modification, distortion, exaggeration, inversion, dissolution, and etc. Parody which is expressed through imitation regarding previous style shows effect of humor or satire, but its characteristics show that it expresses respect or admiration regarding the original The method of irony is showing sarcasm with ironical method regarding the peculiar style of Asian folk costume, and it pursues unexpected shock and joy, and it is closely related to orientalism fashion. Expansion and constancy of Asian look reflects the interest regarding folk of Asia and Asia, and it is a movement which intends new attempt by abolishing stereotype, and furthermore, it is expressing liberty of humans.

디지털아트에 의한 패션일러스트레이션의 소프트웨어 미학 분석 - 아인슈타인의 상대성이론을 중심으로 - (Aesthetic Analysis of Digital Art Using Fashion Illustration Software - Focusing on Alfred Einstein's Theory of Relativity -)

  • 오은경;곽태기
    • 복식
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    • 제60권3호
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    • pp.26-43
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    • 2010
  • The inflow of digital technology into the art, especially in the Fashion Illustration since 1990, makes the new aesthetics of the beginning of the 21 century which the Software aesthetics can be called. The meeting of technology and the art make us recall a great scientist and artist, Leonardo da Vinci in the Renaissance that the notion of the art and skill was unified, same as the ancient history. This study is purposed to expand the concept of the art for the broad exchange of the digital technology and art and for the extensive expression method of the modern fashion illustration. Having views on science theory of the beginning of the 20 century, Theory of Relativity which had given a lot of influence in the philosophy, the litterature and the art, as well as all the science, it makes a connection with the history of art in the beginning of the 20 century and the story of the digital art in the beginning of the 21 century. Firstly, the Fauvism and 2D is based on the expression of the glowing and bright color by the Principle of constancy of light velocity. Secondly, the Cubism and 3D is associated with the Special theory of relativity in the cyberspace which the space and the time are totally accorded. Thirdly, the Futurism and 4D is compared with the General theory of relativity which contains the material and the gravity. They are gradually evolved into the Interactive art and the Kinetic art by the digital technology in the profound cyberspace.