• 제목/요약/키워드: Fraction images

검색결과 216건 처리시간 0.026초

Composition and Distribution of Phytoplankton with Size Fraction Results at Southwestern East/Japan Sea

  • Park, Mi-Ok
    • Ocean Science Journal
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    • 제41권4호
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    • pp.301-313
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    • 2006
  • Abundance and distribution of phytoplankton in seawater at southwestern East/Japan Sea near Gampo were investigated by HPLC analysis of photosynthetic pigments during summer of 1999. Detected photosynthetic pigments were chlorophyll a, b, $c_{1+2}$ (Chl a, Chl b, Chl $c_{1+2}$), fucoxanthin (Fuco), prasinoxanthin (Pras), zeaxanthin (Zea), 19'-butanoyloxyfucoxanthin (But-fuco) and beta-carotene (B-Car). Major carotenoid was fucoxanthin (bacillariophyte) and minor carotenoids were Pras (prasinophyte), Zea (cyanophyte) and But-fuco (chrysophyte). Chl a concentrations were in the range of $0.16-8.3\;{\mu}g/land$ subsurface chlorophyll maxima were observed at 0-10m at inshore and 30-50 m at offshore. Thermocline and nutricline tilted to the offshore direction showed a mild upwelling condition. Results from size-fraction showed that contribution from nano+picoplankton at Chl a maximum layer was increased from 18% at inshore to 69% at offshore on average. The maximum contribution from nano+picoplankton was found as 87% at St. E4. It was noteworthy that contribution from nano+picoplanktonic crysophytes and green algae to total biomass of phytoplankton was significant at offshore. Satellite images of sea surface temperature indicated that an extensive area of the East/Japan Sea showed lower temperature ($<18\;^{\circ}C$) but the enhanced Chi a patch was confined to a narrow coastal region in summer, 1999. Exceptionally high flux of low saline water from the Korea/Tsushima Strait seemed to make upwelling weak in summer of 1999 in the study area. Results of comparisons among Chi a from SeaWiFS, HPLC and fluorometric analysis showed that presence of Chi b cause underestimation of Chi a about 30% by fluorometric analysis but overestimation by satellite data about 30-75% compared to HPLC data.

Submandibular sialolithiasis with CT and scintigraphy: CT values and salivary gland excretion in the submandibular glands

  • Ogura, Ichiro;Hayama, Kazuhide;Sue, Mikiko;Oda, Takaaki;Sasaki, Yoshihiko
    • Imaging Science in Dentistry
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    • 제47권4호
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    • pp.227-231
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    • 2017
  • Purpose: Sialolithiasis is one of the most prevalent large obstructive disorders of the submandibular glands. The aim of this study was to investigate submandibular sialolithiasis with computed tomography (CT) and scintigraphy, with a particular focus on the relationship between CT values of the submandibular glands and their excretion rate. Materials and Methods: Fifteen patients with submandibular sialolithiasis who underwent CT and salivary gland scintigraphy were included in this study. The relationship between the CT values of submandibular glands with and without sialoliths and salivary gland excretion measured using salivary gland scintigraphy was statistically analyzed. Dynamic images were recorded on the computer at 1 frame per 20 seconds. The salivary gland excretion fraction was defined as A (before stimulation test [counts/frame]) / B (after stimulation test [counts/frame]) using time-activity curves. Results: The CT values in the submandibular glands with and without sialoliths was $9.9{\pm}44.9$ Hounsfield units(HU) and $34.2{\pm}21.8HU$, respectively (P=.233). Regarding the salivary gland excretion fraction using scintigraphy, the A/B value in the submandibular glands with sialoliths ($1.09{\pm}0.23$) was significantly lower than in the submandibular glands without sialoliths($1.99{\pm}0.57$, P=.000). Conclusion: Assessments of the CT values and the salivary gland excretion fraction using scintigraphy in the submandibular glands seem to be useful tools evaluating submandibular sialolithiasis.

심전도 게이트 심근관류 Tl-201 SPECT로 측정된 좌심실 기능 및 좌심실 용적의 정확성 (Accuracy of Ventricular Volume and Ejection Fraction Measured by Gated Tl-201 Perfusion Single Photon Emission Tomography)

  • 배문선;문대혁
    • 대한핵의학회지
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    • 제39권2호
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    • pp.94-99
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    • 2005
  • Electrocardiogram-gated single photon omission computed tomography (SPECT) provides valuable information in the assessment of both myocardial perfusion and ventricular function. Tl-201 is a suboptimal isotope for gating. Tl-201 images are more blurred compared with Tc-99m tracers due to the increased amount of scattered photons and use of a smooth filter. The average myocardial count densities are approximately one-half those of conventional technetium tracers. However, Tl-201 is still widely used because of its well-established utility for assessing myocardial perfusion, viability and risk stratification. Gated SPECT with Tl-201 enables us to assess both post-stress and rest left ventricular volume and function. Previous studies with gated Tl-201 SPECT measurements of ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV) have shown high correlation with first-pass radionuclide angiography, gated blood pool scan, Tc-99m-MIBI gated SPECT, contrast ventriculography, echocardiography, and 3-dimensional magnetic resonance imaging. However, problems related to these studies include few agreement data of EDV and ESV, use of a reference method that is likely to have the same systemic errors (gated Tc-99m-MIBI SPECT), and other technical factors related to the count density of gated SPECT. With optimization of gated imaging protocols and more validation studies, gated Tl-201 SPECT would be an accurate method to provide perfusion and function information in patients with coronary artery disease.

잡음이 포함된 측정 자료에 대한 신경망의 DNA 용액 조성비 예측 (Prediction of Composition Ratio of DNA Solution from Measurement Data with White Noise Using Neural Network)

  • 강경희;김민지;이효민
    • Korean Chemical Engineering Research
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    • 제62권1호
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    • pp.118-124
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    • 2024
  • 신경망은 심전도 신호, 망막 영상, 지진파 등 잡음이 포함된 자료의 전처리 작업에 활용되고 있다. 그러나, 잡음의 전처리는 전산시간 증가, 원본 신호의 왜곡등의 문제점을 내포하고 있다. 본 연구에서는 잡음의 전처리 없이 측정 자료를 분석할 수 있는 신경망 구조를 연구하였다. 신경망의 학습 자료로써 잡음이 포함된 DNA 용액의 동역학적 거동을 선정하여, 해당 자료로부터 DNA 용액의 조성비를 예측하고자 하였다. DNA의 동역학 자료에 인위적으로 백색 잡음을 추가하여, 신경망의 예측에 대한 잡음의 영향을 알아보았다. 결과적으로, 잡음의 전처리 없이 O(1)의 신호 대 잡음비 자료로부터 O(0.01)의 오차로 용액의 조성비를 예측할 수 있었다. 이러한 연구 결과는 측정 잡음에 민감하게 영향 받을 수 있는 극미량의 유전병 또는 암세포와 관련된 DNA를 분석을 위한 핵심 인공지능 기술로 활용할 수 있다.

웨이블릿변환과 신경회로를 이용한 동영상의 실시간 전송 (Transmission of Moving Image on the Internet Using Wavelet Transform and Neural Network)

  • 김정하;이학노;남부희
    • 제어로봇시스템학회논문지
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    • 제10권11호
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    • pp.1077-1081
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    • 2004
  • In this Paper we discuss an algorithm for a real-time transmission of moving color image on the TCP/IP network using wavelet transform and neural network. The Image frames received from the camera are two-level wavelet-transformed in the server, and are transmitted to the client on the network. Then, the client performs the inverse wavelet-transform using only the received pieces of each image frame within the prescribed time limit to display the moving images. When the TCP/IP network is busy, only a fraction of each image frame will be delivered. When the line is free, the whole frame of each image will be transferred to the client. The receiver warns the sender of the condition of traffic congestion in the network by sending a special short frame for this specific purpose. The sender can respond to this information of warning by simply reducing the data rate which is adjusted with a neural network or fuzzy logic. In this way we can send a stream of moving images adaptively adjusting to the network traffic condition.

SCV를 장착한 2밸브 Sl 가시화기관의 연소특성에 관한 연구 (A Study of the Combustion Characteristics Using a 2-valve Sl Optically Acessible Engine with SCV)

  • 정구섭;전충환;장영준
    • 대한기계학회논문집B
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    • 제25권12호
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    • pp.1692-1701
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    • 2001
  • This study describes the combustion characteristics under various condition of air excess ratio and ignition timing in a 2-valve SI optically accessible engine with swirl control valve(SCV). It adapted three different types of SCV(open ratio 72.5%, 78%, 59%) to strengthen a swirl flow. Pressure data were acquired using pressure sensor to investigate the effect of swirl flow on combustion, and from these pressure data, IMEP(indicated mean effective pressure) and MFB(mass fraction burnt) were calculated to explain burn rate and flame speed. From acquired flame images, we inspected the flame propagation direction, flame area, and flame centroid. Flame propagation direction showed different tendency between with/without SCV, and flame area with SCV was faster and larger than that of conventional engine. Finally, the representative flame images at each crank angle were acquired by PDF method to verify flame growth process. It is found that strengthened swirl flow is more beneficial for faster and stable combustion.

소수성 텍스쳐 표면에 충돌한 단일 액적의 퍼짐 및 고착 특성 (Spreading and Deposition Characteristics of a Water Droplet Impacting on Hydrophobic Textured Surfaces)

  • 이재봉;문주현;이성혁
    • 한국분무공학회지
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    • 제17권1호
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    • pp.14-19
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    • 2012
  • The present study conducts experimental investigation on spreading and deposition characteristics of a $4.3{\mu}l$ de-ionized (DI) water droplet impacting upon aluminum (Al 6061) flat and textured surfaces. The micro-textured surface consisted the micro-hole arrays (hole diameter: $125{\mu}m$, hole depth: $125{\mu}m$) fabricated by the conventional micro-computer numerical control (${\mu}$-CNC) milling machine process. We examined the surface effect of texture area fraction ${\varphi}_s$ ranging from 0 to 0.57 and impact velocity of droplet ranging from 0.40 m/s to 1.45 m/s on spreading and deposition characteristics from captured images. We used a high-speed camera to capture sequential images for investigate spreading characteristics and the image sensor to capture image of final equilibrium deposition droplet for analyze spreading diameter and contact angle. We found that the deposition droplet on textured surfaces have different wetting states. When the impact velocity is low, the non-wetting state partially exists, whereas over 0.64 m/s of impact velocity, totally wetting state is more prominent due to the increase kinetic energy of impinging droplet.

ALMA/ACA CO (1-0) observations of group galaxies

  • Lee, Bumhyun;Wang, Jing;Chung, Aeree;Ho, Luis C.;Wang, Ran;Shao, Li;Michiyama, Tomonari;Wang, Shun;Peng, Eric W.;Kilborn, Virginia
    • 천문학회보
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    • 제45권1호
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    • pp.64.1-64.1
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    • 2020
  • Galaxy groups are the place where many galaxies feel the impact of the surroundings (e.g., merging, tidal interaction, ram pressure stripping) before joining bigger structures like (sub)clusters. A significant fraction of galaxies is quenched in the group environment. Such "pre-processing" of galaxies in groups is likely to affect galaxy evolution tremendously. To better understand how environmental processes in galaxy groups affect molecular gas, star formation activity, and galaxy evolution, we carried out CO imaging observations of group galaxies, using the Atacama Compact Array (ALMA/ACA). We selected all the targets that have been detected in the GEMS-HI survey for two groups, making the sample of 40 galaxies (18 galaxies in IC 1459 group and 22 galaxies in NGC 4636 group). Our ALMA/ACA observation is the first CO imaging survey for two groups. In this work, we present CO images of group galaxies, together with their star formation maps and HI images. Our ACA CO data show the asymmetric distribution of molecular gas in some of our samples. We discuss the impact of the group environment on molecular gas and star formation activity.

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SPECT/CT 영상에서 에너지창 기반 산란보정과 CT 기반 산란보정 방법의 정량적 정확성 비교 (The Comparison of Quantitative Accuracy Between Energy Window-Based and CT-Based Scatter Correction Method in SPECT/CT Images)

  • 김지현;손현수;이주영;박훈희
    • 핵의학기술
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    • 제19권2호
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    • pp.93-101
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    • 2015
  • SPECT영상에서 산란계수는 정량적 계수오차와 영상품질 저하의 요인이다. 이에 다양한 산란보정(Scatter Correction, SC)방법이 연구되어 왔으며, 본 연구에서는 기존의 에너지창(Energy Window, EW) 기반 SC(EWSC)와의 비교로 SPECT/CT에서 사용되는 CT 기반 SC(CTSC)의 정확성을 평가하고자 한다. 중앙에 열소막대(hot rod, 74.0 MBq)를 설정한 Triple line insert 팬텀의 내부에 산란계수의 영향이 없는 기준영상의 획득을 위하여 공기를 채운 후 SPECT /CT영상을 획득하였고, 같은 조건에서 산란계수의 영향을 유도하기 위하여 공기대신 물을 채운 후 SPECT/CT영상을 각각 별도로 획득하였다. 두 조건 모두 Astonish(iterative : 4, subset : 16) 재구성 방법과 CT감쇠보정을 공통 적용하였고, 물을 채운 영상에 비산란보정(NSC), EWSC, CTSC 3가지 유형의 산란보정방법을 사용하였다. EWSC를 위하여 주(=peak) 에너지창(140 keV, 20%) 이외에 보조 에너지창 9개를 추가 설정한 후 영상을 동시 획득하였고, EWSC의 종류는 DPW(dual photopeak window) 10%, DEW (dual energy window)20%, TEW(triple energy window)10%, TEW5.0%, TEW2.5% 5가지를 사용하였다. 일차(primary)계수의 변동이 없는 조건하에, 두 조건의 영상에 VOI를 그려 총계수를 측정한 후 총계수 중 산란계수의 비를 %SF(percent scatter fraction)로 구하고, 공기를 채운 영상을 기준으로 물을 채운 영상과의 계수차이를 %NMSE (per cent normalized mean-square error)로 평가하였다. 공기를 채운 영상을 기준으로 각 산란보정방법이 적용된 물을 채운 영상의 %SF는 NSC 37.44, DPW 27.41, DEW 21.84, TEW10% 19.60, TEW5% 17.02, TEW2.5% 14.68, CTSC 5.57로 CTSC에서 제거된 산란계수가 가장 많았으며, %NMSE는 NSC 35.80, DPW 14.28, DEW 7.81, TEW10% 5.94, TEW5% 4.21, TEW2.5% 2.96, CTSC 0.35로 CTSC에서 가장 낮게 나타났다. SPECT/CT영상에서 실험에 사용된 각 산란보정 방법의 적용은 산란계수의 영향으로 발생된 정량적 계수오차를 개선시킬 수 있었다. 특히, CTSC의 경우 기존의 EWSC방법들과 비교하여 가장 낮은 %NMSE (=0.35)를 보여 비교적 정확한 산란보정이 가능하였다.

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견관절 운동 분율의 측정 (Measurement of shoulder motion fraction and motion ratio)

  • 강영한
    • 대한방사선기술학회지:방사선기술과학
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    • 제29권2호
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    • pp.57-62
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    • 2006
  • 연구 목적: 견관절 운동분율과 운동비의 측정과정을 이해하고, 견갑 흉곽관절과 관절와 상완관절의 운동비의 기준을 제시하고자 함이다. 연구대상 및 방법: 100명의 건강한 대상자를 연령대별(20, 30, 40, 50, 60대)로 20명씩 나누어 각각의 견관절 촬영과 분율을 계산하였다. 견갑극에 수직이고 관절와 면에 평행인 상을 재현하기 위하여 상완이 자연지위일 때 머리 방향 $15^{\circ}$, 90도 거상 시 $19^{\circ}$, 최대 거상 시 $22^{\circ}$로 입사각을 적용하였고, 몸의 회전 각도는 $40^{\circ},\;36^{\circ},\;22^{\circ}$로 시상면에서 외전시키며 촬영하였다. 관절운동 방향에 따른 운동 범위를 확인하기 위해, 측각도계(goniometer)를 이용하여 양측 견관절의 운동범위를 측정하였다. 전운동의 팔의 각도와 방사선 영상의 팔의 각도를 측정하여 상완관절 운동 각도와 견갑 흉곽관절의 운동 각도를 계산하였다. 결 과: 오른팔의 운동 분율은 $90^{\circ}$에서 남자 1.22, 여자 1.70 이었고, 최대 거상 시 1.63, 1.84였다. 왼팔은 $90^{\circ}$에서 1.31, 1.54, 최대 거상 시 각각 1.57, 1.32였다. 오른 우세팔은 $90^{\circ}$에서 1.58, 최대 거상 시 1.43이었고, 왼쪽 우세팔 각각 1.82, 1.94였다. 20대에서는 $90^{\circ}$ 거상 시 1.56, 최대 거상 시 1.52였고, 30대는 1.82, 1.43, 40대는 1.23, 1.16, 50대는 1.80, 1.28, 60대는 1.24, 1.75로 나타났다. 견관절의 운동 특성상 남녀에 따른 운동비, 우세팔과 비우세팔, 연령대에 따른 운동비를 측정하여 비교해 본 결과 유의한 차이가 없었다. 결 론: 견관절 운동 분율의 기준은 견관절의 운동장애를 확인하고 견관절 질환의 치료 후 정상적인 견관절 기능회복 여부를 확인하는데 도움을 줄 수 있을 것이다. 견관절 운동비 측정을 위한 운동 각도를 정확하게 측정할 수 있고, 실제 운동비를 계산할 수 있으면 방사선학적 자세와 입사각 설정에도 유용할 것이다.

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