• 제목/요약/키워드: postprocessing

검색결과 232건 처리시간 0.02초

Quantitative Digital Subtraction Angiography in Pediatric Moyamoya Disease

  • Cheon, Jung-Eun
    • Journal of Korean Neurosurgical Society
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    • 제57권6호
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    • pp.432-435
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    • 2015
  • Moyamoya disease is a unique cerebrovascular disorder characterized by idiopathic progressive stenosis at the terminal portion of the internal carotid artery (ICA) and fine vascular network. The aim of this review is to present the clinical application of quantitative digital subtraction angiography (QDSA) in pediatric moyamoya disease. Using conventional angiographic data and postprocessing software, QDSA provides time-contrast intensity curves and then displays the peak time ($T_{max}$) and area under the curve (AUC). These parameters of QDSA can be used as surrogate markers for the hemodynamic evaluation of disease severity and quantification of postoperative neovascularization in moyamoya disease.

KIVA3V와 SWEEP을 이용한 디젤 엔진에서의 soot 총량 및 입자 크기 분포 예측 (Prediction of Soot Emissions and Particle Size distribution by KIVA3V and SWEEP in a diesel engine)

  • 이재서;허강열
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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    • pp.129-132
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    • 2012
  • Computation is performed to predict number density, volume fraction and size distribution of soot particles in typical operating conditions of a diesel engine. KIVA has been integrated with the CMC routine to consider turbulence/chemistry coupling and gas phase kinetics for heat release and soot precursors. The compositions of soot precursors are estimated by tracking Lagrangian particles to consider spatial inhomogeneity and differential diffusion in KIVA. The soot simulator SWEEP is employed as a postprocessing step to calculate conditional and integral quantities of soot particles.

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자동문서판독 후처리를 위한 수정된 n-gram 알고리즘 (A Modified Binary n-gram Algorithm for the postprocessing of the Automatic Document Reading)

  • 김일회;유근호;이철희
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
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    • pp.1352-1355
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    • 1987
  • This Paper proposed the modified binary n-gram algorithm for the contextual post processing system in English sentence. Backward gram was used to correct the first position error in a word. It is not requires additional storage but more times of comparison it allows interactive correction routine. Experiments were implemented using PASCAL language on a micro computer, IBM PC/XT. This algorithm improves the correction rate around $4{\sim}5%$ on a limited experimental environments.

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새로운 연산자를 이용한 통계적인 윤곽선 추출기법 (Statistical Edge Detecting Method Using a New operator.)

  • 이해영;김훈학;이근영
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
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    • pp.1394-1397
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    • 1987
  • It is difficult to detect edge segments from a noisy image since the image have a noise in piratical applications which utilize some type of visual input capability. Hence, the proposed algorithm consists of the modality tests based on parallel statistical tests without a noise removal preprocessing or postprocessing, and the edge detection technique With one-Pixel edge segments in this paper. The algorithm is very reliable and effective in the case of those situations where the Picture is poor quality and low resolution. And it does'nt require thinning operation and thresholding in hand. Experimental comparision With the more conventional techniques when applied to typical low-quality Pictures confirms good capabilities of the algorithm.

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어절 정보를 이용한 한국어 문자 인식 후처리 기법 (A postprocessing method for korean optical character recognition using eojeol information)

  • 이영화;김규성;김영훈;이상조
    • 전자공학회논문지C
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    • 제35C권2호
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    • pp.65-70
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    • 1998
  • In this paper, we will to check and to correct mis-recognized word using Eojeol information. First, we divided into 16 classes that constituents in a Eojeol after we analyzed Korean statement into Eojeol units. Eojeol-Constituent state diagram constructed these constitutents, find the Left-Right Connectivity Information. As analogized the speech of connectivity information, reduced the number of cadidate words and restricted case of morphological analysis for mis-recognition Eojeol. Then, we improved correction speed uisng heuristic information as the adjacency information for Eojeol each other. In the correction phase, construct Reverse-Order Word Dictionary. Using this, we can trace word dictionary regardless of mis-recongnition word position. Its results show that improvement of recognition rate from 97.03% to 98.02% and check rate, reduction of chadidata words and morpholgical analysis cases.

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블록화 현상 제거를 위한 반복임계저역여파기 (Iterative Thresholded Lowpass Filter for Blocking Effect Removal)

  • 김상호;정해묵;이병욱;장규환;유시룡
    • 전자공학회논문지B
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    • 제32B권1호
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    • pp.103-109
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    • 1995
  • In this paper, we propose a postprocessing method that neatly removes blocking effect but retains visually important image details and edges. The iterative thresholded lowpass filter is basically a low pass filter whose ouput depends on three variable elements. I.e. iteration number, threshold value and passband width. The threshold value restricts the difference between the output of the proposed filter and the original input independent of the iteration number. With this property, the iterative thresholded lowpass filter can retain most of the image details while smoothing the block boundaries. The other two variable elements, i.e. iteration number and passband width, can determine the convergence speed of the proposed filter. In this paper, we also propose several adaptive filtering techniques based on the iterative thresholded lowpass filter with their simulation results.

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웨이블릿 압축 동영상의 정칙화 기반 적응적 개선에 관한 연구 (Adaptive Regularized Enhancement of Wavelet Compressed Video)

  • 정정훈;기현종;이성원;백준기
    • 대한전자공학회논문지SP
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    • 제41권4호
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    • pp.39-44
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    • 2004
  • 움직임 보상을 고려한 3차원 웨이블릿 변환은 공간적, 시간적인 상관관계에 중복된 정보를 효과적으로 제거한다. 그러나 웨이블릿 방식으로 압축된 영상이라 하더라도 압축률이 높은 경우 고주파 서브밴드의 변환계수가 상당수 손실되어 압축복원 시에 링 현상과 같은 왜곡이 생긴다. 본 논문에서는 이러한 3차원 웨이블릿의 압축왜곡을 줄이기 위하여 적응적 반복 복원 기법을 사용하는 새로운 알고리듬을 제안하였다. 제안된 적응적 기법에서는 에지의 방향에 따라 서로 다른 고역통과필터를 정칙화 복원에 사용하였다.

HOS를 이용한 통신 채널의 역 모델링에 관한 연구 (A study on the iverse modeling of communication channel by HOS)

  • 임성각;진용옥
    • 한국통신학회논문지
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    • 제21권5호
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    • pp.1274-1282
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    • 1996
  • This paper deals with an inverse modeling of nonminimum phase communication channel utilizing the HOS (High Order Statistics) of the received signal. After the communication channel is separated into the minimum phase and maximum phase components, the inverse modeling is performed independently. The performance superiority is confirmed by monte-carlo computer simulation in comparison with the traditional CMA (Constant Modulus Algorithm) method. By utilizing the proposed algorithm employing the HOS of the received signal, the inverse frequency characteristics of the channel can be obtained withoug transmitted signal in digital communication. This algorithm is required in preprocessing or postprocessing in order to remove the channel effect, and effective in the self adaptive equalizer which can minimize the bit error rate or symbol error rate in the recovry of received signal.

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온-라인 데이터 가시화 프로그램의 개발과 그 적용 (DEVELOPMENT OF ON-LINE DATA VISUALIZATION PROGRAM AND ITS APPLICATION)

  • 강상현;김병수
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2008년도 학술대회
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    • pp.290-296
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    • 2008
  • In this paper development of on-line data visualization program is described and some examples of data postprocessing are shown. The program is written in JAVA language and runs as a JAVA applet on the web browser such as Internet Explorer or Firefox. Remote users can use the program to visualize and analyze their own flow data by accessing the program server through the internet and loading data files in proper formats from their local computers. This paper describes briefly about algorithms for data visualization, structure and available functions of the program, and web sever system. The mechanism of how the JAVA applet can access and process local data files and relevant coding techniques are explained as well. Also explained is what is required for the remote users and client computers to access the program on-line. Some visualization examples performed on a local computer are illustrated by accessing the server remotely.

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Reperfusion Hyperemia Demonstrated on Perfusion MRI: It′s Relationship with Programmed Cell Death

  • 이승구;김동익;김상흠;김시연;인연권
    • 대한자기공명의과학회:학술대회논문집
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    • 대한자기공명의과학회 2001년도 제6차 학술대회 초록집
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    • pp.170-170
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    • 2001
  • Purpose: To evaluate the relationship between reperfusion hyperemia in reversible cerebral ischem and the degree of programmed cell death. Method: We produced the animal models of reversible cerebral ischemia in 10 cats by mean of middle cerebral artery (MCA) occlusion with transorbital approach. MCA was occluded b microvascular clamp for an hour. MR imaging was performed at 0, 1, 2 days after ischemi and reperfusion. Perfusion (PWI) [Contrast enhanced GRE EPI, TR/TE= 1500/40, 40 Phases, 128 matrix, 12 cm FOV] and diffusion (DWI) (SE EPI, b=0, 500, 1000) weighted images were obtained using Philips Intera 1.57 system. rCBV and ADC maps were calculated wi IDL based postprocessing program. Tissue slices were obtained after the last MR imagin TUNEL, Calbin and Acid-Fuscin staining were done for corresponding slices as MR imagin We investigated the differences of degree of apoptosis in the area of reperfusion hyperemia.

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