• Title/Summary/Keyword: velocity encoding

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Measurement of Flow Velocity and Flow Visualization with MR PC Image (MR PC 영상을 이용한 유체 흐름 분석)

  • Kim, S.J.;Lee, D.H.;Min, B.G.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.05
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    • pp.127-130
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    • 1997
  • Phase-contrast(PC) methods have been used for quantitative measurements of velocity and volume flow rate. In addition, phase contrast cine magnetic resonance imaging (MRI) combines the flow dependent contrast of PC MRI with the ability of cardiac cine imaging to produce images throughout the cardiac cycle. In this method, the through-plane velocity has been encoded generally. However, the accuracy of the flow data can be reduced by the effect of flow direction, finite slice thickness, resolution, pulsatile flow pattern, and so on. In this study we calculated the error caused by misalignment of tomographic plane and flow directon. To reduce this error and encode the velocity for more complex flow, we suggested 3 directional velocity encoding method.

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Velocity Measurement System Design Based on Quantization Error Constraint

  • Katsunori, Shida;Toyonori, Matsuda
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.86.1-86
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    • 2001
  • Combined with a counter, wheel or strip encoders which have equally divided markers are one of frequent measuring choices towards various applications in terms of cost, simplicity, and diversity of measurements, e.g., measuring displacement, velocity, acceleration, and so on. Often, velocity is measured by counting the series of reference clocks for a period of time which sensor-carrying device took for traveling two adjacent encoding markers. Quantizaion error of such that the disturbance caused by quantization error is under control. This paper identifies design issues, developes theory, and proposes a paradigm to design a velocity measurement system such ...

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On a Study of Measurement Method of Utterance Velocity for the Reduction of Transmission Rate in CELP Vocoder. (LSP 파라미터를 이용한 발성측정법)

  • 장경아;배명진
    • Proceedings of the IEEK Conference
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    • 2000.11d
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    • pp.199-202
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    • 2000
  • Speaking Rate has variety depends on the situation and habit of speakers. It has been many studied about speaking rate In speaker recognition. The study of speaking rate in speech recognition is one of considerable matter when It is recognized the speakers and it is measured by many speech data base and complicate estimation for accuracy. In this paper, conventional vocoder process the speech signal when encoding and transmitting without regard to speaking rate so in order to apply the speaking rate for vocoder It should be considered the simpler algorithm and less computation amount than the conventional method of speaking rate used In speech recognition. We proposed the speaking rate algorithm which is used the simple parameter with Line Spectrum Pair (LSP). The proposed peaking rate method is measured by the information of LSP in speech. We measured the variety rate of phenomenon about utterances which have different velocity, respectively. As a result, It has distinct variation rate of phenomenon between utterances uttered fast and slow and the rate is 42.8% higher in case of uttered fast than in case of uttered slow.

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Blood Flow Measurement with Phase Contrast MRI According to Flip Angle in the Ascending Aorta (위상대조도 MRI에서 숙임각에 따른 상행대동맥의 혈류 측정)

  • Kim, Moon Sun;Kweon, Dae Cheol
    • Journal of the Korean Magnetics Society
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    • v.26 no.4
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    • pp.142-148
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    • 2016
  • To evaluate the effect of flip angle on flow rate measurements obtained with phase contrast MRI according to the flip angle degree in ascending aorta and velocity encoding (VENC) was (150 m/s). 1.5T MRI in patients 17 (female: 8, male: 9, mean age $57.9{\pm}15.4$) as a target by applying a non-breath holding techniques to flip angle VENC (150 cm/s) in each of the ascending aorta was measured by changing $20^{\circ}$, $30^{\circ}$ and $40^{\circ}$. Blood was obtained a peak velocity, average velocity, net forward volume, net forward volume/body surface area. Ascending aorta from average velocity (AV) measured the average value of the flip angle $20^{\circ}$ (9.87 cm/s), $30^{\circ}$ (9.6 cm/s) and $40^{\circ}$ (10.05 cm/s). Blood flow VENC in was blood flow change in flip angle change was high most blood flow measurement when the flip angle $30^{\circ}$ in VENC, crouching each blood flow is also proportional to the increases in the $20^{\circ}$ to $40^{\circ}$ and was increased, the deviation of the peak velocity and the average velocity is the smallest deviation from the flip angle $30^{\circ}$. Flip angle $20^{\circ}$, $30^{\circ}$ and $40^{\circ}$ in peak velocity, average velocity, net forward volume, net forward volume/body surface area was no statistically significant difference (p > .05). Blood flow velocity and blood flow is measured by applying to adjust the flip angle accurately calculate the blood flow is important information for diagnosis and treatment of cardiovascular diseases, and can help in the examination on the blood flow measurement.

Characterization of a Paenibacillus woosongensis ${\beta}$-Xylosidase/${\alpha}$-Arabinofuranosidase Produced by Recombinant Escherichia coli

  • Kim, Yeon-A;Yoon, Ki-Hong
    • Journal of Microbiology and Biotechnology
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    • v.20 no.12
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    • pp.1711-1716
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    • 2010
  • A gene encoding the ${\beta}$-xylosidase/${\alpha}$-arabinofuranosidase (XylC) of Paenibacillus woosongensis was cloned into Escherichia coli. This xylC gene consisted of 1,425 nucleotides, encoding a polypeptide of 474 amino acid residues. The deduced amino acid sequence exhibited an 80% similarity with those of both Clostridium stercorarium ${\beta}$-xylosidase/${\alpha}$-N-arabinosidase and Bacillus cellulosilyticus ${\alpha}$-arabinofuranosidase, belonging to the glycosyl hydrolase family 43. The structural gene was subcloned with a C-terminal His-tag into a pET23a(+) expression vector. The His-tagged XylC, purified from a cell-free extract of a recombinant E. coli BL21(DE3) Codon Plus carrying a xylC gene by affinity chromatography, was active on para-nitrophenyl-${\alpha}$-arabinofuranoside (pNPA) as well as para-nitrophenyl-${\beta}$-xylopyranoside (pNPX). However, the enzymatic activities for the substrates were somewhat incongruously influenced by reaction pHs and temperatures. The enzyme was also affected by various chemicals at different levels. SDS (5 mM) inhibited the enzymatic activity for pNPX, while enhancing the enzymatic activity for pNPA. Enzyme activity was also found to be inhibited by addition of pentose or hexose. The Michaelis constant and maximum velocity of the purified enzyme were determined for hydrolysis of pNPX and pNPA, respectively.

Motion Style Transfer using Variational Autoencoder (변형 자동 인코더를 활용한 모션 스타일 이전)

  • Ahn, Jewon;Kwon, Taesoo
    • Journal of the Korea Computer Graphics Society
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    • v.27 no.5
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    • pp.33-43
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    • 2021
  • In this paper, we propose a framework that transfers the information of style motions to content motions based on a variational autoencoder network combined with a style encoding in the latent space. Because we transfer a style to a content motion that is sampled from a variational autoencoder, we can increase the diversity of existing motion data. In addition, we can improve the unnatural motions caused by decoding a new latent variable from style transfer. That improvement was achieved by additionally using the velocity information of motions when generating next frames.

Diffusion Tensor Imaging and Cerebrospinal Fluid Flow Study of Cine Phase Contrast in Normal Cervical Spinal Cords (정상인 경수에 대한 확산텐서영상과 PC기법을 이용한 뇌척수액 속도 측정에 관한 연구)

  • Son, B.K.;Kwak, S.Y.;Han, Y.H.;Yoo, J.S.;Kim, O.H.;Ko, H.Y.;Mun, C.W.
    • Investigative Magnetic Resonance Imaging
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    • v.17 no.2
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    • pp.123-132
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    • 2013
  • Purpose : We report the results of the various parameters of diffusion tensor imaging (DTI) and CSF flow study of the cervical spinal cord using magnetic resonance (MR) imaging techniques. Materials and Methods: Intramedullary FA and MD were measured in the gray matter and posterior cord of the white matter and both lateral cords of the white matter at the C2-3, C4-5, C5-6 spinal levels. For the CSF flow study, velocity encoding was obtained at the C2-3, C4-5, C5-6 spinal levels. Results: There was a significant difference of the FA and MD between the white matter and gray matter (p < 0.05). The FA of the gray matter was significantly different according to the cervical spinal cord levels (p < 0.05). Otherwise, the FA and MD parameters were not significantly different (p > 0.05). The mean peak systolic velocity and mean peak diastolic velocity were $5.18{\pm}2.00cm/sec$ and $-7.32{\pm}3.18cm/sec$, respectively from C2 to C6 spinal cords. There was no significant difference in these velocities among the cervical spinal cord (p > 0.05). Conclusion: This basic information about DTI and CSF dynamics of the cervical spinal cord may be useful for assessing cervical spinal cord abnormalities using MR imaging.

Expression of Human Liver 3,4-Catechol estrogens UDP-Glucuronosyltransferase cDNA in COS 1 Cells

  • Ahn, Mee-Ryung;Owens, Ida-S.;Sheen, Yhun-Yhong
    • Archives of Pharmacal Research
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    • v.20 no.5
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    • pp.465-470
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    • 1997
  • The human cDNA clone UDPGTh2, encoding a liver UDP-glucuronosyltransferase (UDPGT), was isolated from a .gamma.gt 11 cDNA library by hybridization to mouse transferase cDNA clone, UDPGTm1. The two clones had 74% nlicleotide sequence identities in the coding region. UDPGTh2 encoded a 529 amino acid protein with an amino terminus membrane-insertion signal peptide and a carboxyl terminus membrane-spanning region. In order to establish substrate specificity, the clone was inserted into the pSVL vector (pUDPGTh2) and expressed in COS 1 cells. Sixty potential substrates were tested using cells transfected with pUDPGTh2. The order of relative substrate activity was as follows: 4-hydroxyestrone > estriol >2-hydroxyestriol > 4-hydroxyestradiol > $6{\alpha}$-hydroxyestradiol >$5{\alpha}$-androstane-$3{\alpha}$, $11{\beta}$, $17{\beta}$-triol=5${\beta}$-androstane-$3{\alpha}$ ${\beta}$, $17{\beta}$-triol. There were only trace amounts of gulcuronidation of 2-hydroxyestradiol and 2-hydroxyestrone, and in contrast to other cloned transferase, no gulcuronidation of either the primary estrogens and androgens (estrone, $17{\beta}$estradiol/testosterone, androsterone) or any of the exogenous substrates tested was detected. A lineweaver-Burk plot of the effect of 4-hydroxystrone concentration on the velocity of glucuronidation showed an apparent Km of $13{\mu}M$. The unique specificity of this transferase might play an important role in regulating the level and activity of these potent and active estrogen metabolites.

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Sensitivity Optimization of MEMS Gyroscope for Magnet-gyro Guidance System (자기-자이로 유도 장치를 위한 MEMS형 자이로의 민감도 최적화)

  • Lee, Inseong;Kim, Jaeyong;Jung, Eunkook;Jung, Kyunghoon;Kim, Jungmin;Kim, Sungshin
    • The Journal of Korea Robotics Society
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    • v.8 no.1
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    • pp.29-36
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    • 2013
  • This paper presents a sensitivity optimization of a MEMS (microelectromechanical systems) gyroscope for a magnet-gyro system. The magnet-gyro system, which is a guidance system for a AGV (automatic or automated guided vehicle), uses a magnet positioning system and a yaw gyroscope. The magnet positioning system measures magnetism of a cylindrical magnet embedded on the floor, and AGV is guided by the motion direction angle calculated with the measured magnetism. If the magnet positioning system does not measure the magnetism, the AGV is guided by using angular velocity measured with the gyroscope. The gyroscope used for the magnet-gyro system is usually MEMS type. Because the MEMS gyroscope is made from the process technology in semiconductor device fabrication, it has small size, low-power and low price. However, the MEMS gyroscope has drift phenomenon caused by noise and calculation error. Precision ADC (analog to digital converter) and accurate sensitivity are needed to minimize the drift phenomenon. Therefore, this paper proposes the method of the sensitivity optimization of the MEMS gyroscope using DEAS (dynamic encoding algorithm for searches). For experiment, we used the AGV mounted with a laser navigation system which is able to measure accurate position of the AGV and compared result by the sensitivity value calculated by the proposed method with result by the sensitivity in specification of the MEMS gyroscope. In experimental results, we verified that the sensitivity value through the proposed method can calculate more accurate motion direction angle of the AGV.

Artifacts due to Retrograde Flow in the Artery and Their Elimination in 2D TOF MR Angiography (2D TOF 자기공명 혈관조영술에서 동맥혈류의 역류로 인한 영상훼손과 이의 제거)

  • Jung, K.J.;Lee, J.K.;Kim, S.K.;Park, S.H.
    • Investigative Magnetic Resonance Imaging
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    • v.5 no.1
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    • pp.38-42
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    • 2001
  • Dark band artifacts are often observed in angiograms of arteries obtained by 2D time-of-flight (TOF) angiography with saturation of veins by presaturation RF pulses. At some arteries the arterial blood velocity varies in a triphasic pattern during a cardiac cycle. The arterial blood, that is saturated by presaturation RF pulses in the saturation band, can flow back into the imaging slice during the retrograde flow phase of the triphasic variation. When such saturated retrograde flow occurs during the acquisition of the central part of the K space, a signal void can result in base images and consequently dark band artifacts can appear in angiograms. This phenomenon is experimentally demonstrated by varying the gap between the imaging slice and the saturation band. Furthermore, a new pulse sequence is proposed to eliminate the dark band artifacts by changing the profile of the saturation band front a rectangle to a ramp.

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