• Title/Summary/Keyword: 후지타 방법

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History of solving polynomial equation by paper folding (종이접기를 활용한 방정식 풀이의 역사)

  • CHOI Jaeung;AHN Jeaman
    • Journal for History of Mathematics
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    • v.36 no.1
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    • pp.1-17
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    • 2023
  • Paper folding is a versatile tool that can be used not only as a mathematical model for analyzing the geometric properties of plane and spatial figures but also as a visual method for finding the real roots of polynomial equations. The historical evolution of origami's geometric and algebraic techniques has led to the discovery of definitions and properties that can enhance one's cognitive understanding of mathematical concepts and generate mathematical interest and motivation on an emotional level. This paper aims to examine the history of origami geometry, the utilization of origami for solving polynomial equations, and the process of determining the real roots of quadratic, cubic, and quartic equations through origami techniques.

Evaluation of Resolution Characteristics by Using Chart Device Angle (차트 각도를 이용한 해상력 특성 평가)

  • Min, Jung-Whan;Jeong, Hoi-Woun
    • Journal of radiological science and technology
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    • v.44 no.4
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    • pp.375-380
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    • 2021
  • This study aim was quantitative assessment of MTFs of spectrum of the square wave chart images and Coltman chart images for 0°, 1.7°, 2.2°, 2.9°, 4.1° by using chart method. In general device was AccuRay-650 (DK Medical System, Korea) used, indirect flat panel detector(FPD) Aero (Konica, Japan) used and MATLAB R2019a (MathWorks, USA) used. The result of comparison for each angle of MTF the edge image was highest quantitatively value for MTF finding of showed the best value of 0.1 based on the frequency of 3.5 mm-1, value of 0.1 based on the square wave was frequency of 3.0 mm-1 and value of 0.1 based on the Coltman transform was frequency of 2.4 mm-1. In this study it was significant that the methodology of the international Electro-technical Commission was applied mutandis by using the Fujita method within 2~3°.

Correction Method of Slit Modulation Transfer function on Digital Medical Imaging System (디지털 의료영상에서 슬릿법에 의한 Modulation Transfer Function의 보정방법)

  • Kim, Jung-Min;Jung, Hoi-Woun;Min, Jung-Whan;Im, Eon-Kyung
    • Journal of radiological science and technology
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    • v.29 no.3
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    • pp.133-139
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    • 2006
  • By using CR image pixel data, We examined the way how to calculate the MTF and digital characteristic curve. It can be changed to the text-file(Excel) from a pixel data which was printed with a digital x-ray equipment. In this place, We described the way how to figure out and correct the sharpness of a digital images of the MTF from FUJITA. Excel program was utilized to calculate from radiography of slit. Digital characteristic curve, Line Spread Function, Discrete Fourier Transform, Fast Fourier Transform digital specification curve, were indicated in regular sequence. A big advantage of this method, It can be understood easily and you can get results without costly program and without full knowledge of computer language. It shows many different values by using different correction methods. Therefore we need to be handy with appropriate correction method and we should try many experiments to get a precise MTF figures.

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Study on the Resolution Characteristics by Using Magnetic Resonance Imaging 3.0T (3.0T 자기공명영상을 이용한 해상력 특성에 대한 연구)

  • Min, Jung-Whan;Jeong, Hoi-Woun;Han, Ji-Hyun;Lee, Si-Nae;Han, Song-Yi;Kim, Ki-Won;Kim, Hyun-Soo;Son, Jin-Hyun
    • Journal of radiological science and technology
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    • v.43 no.4
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    • pp.251-257
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    • 2020
  • This study was purpose to quantitative evaluation of edge method of modulation transfer function(MTF) and physical image characteristics of by obtain the optimal edge image by using magnetic resonance imaging(MRI). The MRI equipment was used (MAGNETOM Vida 3.0T MRI, Siemense healthcare system, Germany) and the head/neck matrix shim MR coil were 20 channels(elements) receive coil. The MTF results of showed the best value of 0.294 based on the T2 Nyquist frequency of 1.0 mm-1. The MTF results of showed that the T1 image is 0.160, the T1 CE image is 0.250, T1 Conca2 image is 0.043, and the T1 CE (Concatenation) Conca2 image is 0.190. The T2 image highest quantitatively value for MTF. The physical image characteristics of this study were to that can be used efficiently of the MRI and to present the quantitative evaluation method and physical image characteristics of 3.0T MRI.

Study on the Physical Imaging Characteristics by Using Magnetic Resonance Imaging 1.5T (1.5T 자기공명영상을 이용한 물리적 영상 특성에 대한 연구)

  • Min, Jung-Whan;Jeong, Hoi-Woun;Han, Ji-Hyun;Lee, Si-Nae;Park, Jang-Ho;Kim, Ki-Won;Kim, Hyun-Soo
    • Journal of radiological science and technology
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    • v.42 no.5
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    • pp.329-334
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    • 2019
  • This study was purpose to quantitative evaluation of noise power spectrum(NPS) and studied the quantitative evaluation and characteristics of modulation transfer function(MTF) by obtain the optimal edge image by using Coil in magnetic resonance imaging(MRI) equipment through Fujita theory using edge method. The MRI equipment was used (Tim AVANTO 1.5T, Siemense healthcare system, Germany) and the head matrix coil were 12channels(elements) receive coil. The NPS results of showed the best value of 0.004 based on the T2 Nyquist frequency of $1.0mm^{-1}$, and the MTF results of showed that the T1 and T2 values were generally better than the T1 CE and T1 CE FC values. The characteristics of this study were to explain the characteristic method of image quality evaluation in general. To present the quantitative evaluation process and results in the evaluation of MRI image characteristics in radiology.

Evaluation of the Resolution Characteristics by Using American College of Radiology Phantom for Magnetic Resonance Imaging (자기공명영상에서 ACR 팬텀을 이용한 해상력 특성 평가)

  • Min, Jung-Whan;Jeong, Hoi-Woun;Han, Ji-Hyun;Lee, Si-Nae;Kim, Min-Ji;Kim, Seung-Chul
    • Journal of radiological science and technology
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    • v.45 no.1
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    • pp.11-17
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    • 2022
  • This study was purpose to quantitative assessment of the resolution characteristics by using American college of radiology(ACR) phantom for magnetic resonance imaging (MRI). The MRI equipment was used (Achiva 3.0T MRI, Philips system, Netherlands) and the head/neck matrix shim SENSE head coil were 32 channels(elements) receive MR coil. And the MRI equipment was used (Discovery MR 750, 3.0T MRI, GE medical system, America) and the head/neck matrix shim MC 3003G-32R 32-CH head coil were receive MR coil. As for the modulation transfer function(MTF) comparison result by using ACR magnetic resonance imaging phantom, the MTF value of the ACR standard T2 image in GE equipment is 0.199 when the frequency is 1.0 mm-1 and the MTF value of the hospital T2 image in Philips equipment is 0.528. It was used efficiently by using a general sequence more than the standard sequence method using the ACR phantom. In addition it is significant that the quantitative quality assurance evaluation method for resolution characteristics was applied mutatis mutandis, and the result values of the physical image characteristics of the 3.0T MRI device were presented.

Quantitative Evaluation of the Corticospinal Tract Segmented by Using Co-registered Functional MRI and Diffusion Tensor Tractography (정상인에서 기능적 뇌 자기공명영상과 확산텐서영상 합성기법을 이용한 피질척수로의 위치에 따른 정량적 분석)

  • Jang, Sung-Ho;Hong, Ji-Heon;Byun, Woo-Mok;Hwang, Chang-Ho;Yang, Dong-Seok
    • Investigative Magnetic Resonance Imaging
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    • v.13 no.1
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    • pp.40-46
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    • 2009
  • Purpose : The purpose of this study was to investigate the quantitative evaluation of the corticospinal tract (CST) at the multiple levels by using functional MRI (fMRI) co-registered to diffusion tensor tractography (DTT). Materials and Methods : Ten normal subjects without any history of neurological disorder participated in this study. fMRI was performed at 1.5 T MR scanner using hand grasp-release movement paradigm. DTT was performed by using DtiStudio on the basis of fiber assignment continuous tracking algorithm (FACT). The seed region of interest (ROI) was drawn in the area of maximum fMRI activation during the motor task of hand grasp-release movement on a 2-D fractional anisotropy (FA) color map, and the target ROI was drawn in the cortiocospinal portion of anterior lower pons. We have drawn five ROIs for the measurement of FA and apparent diffusion coefficient (ADC) along the corona radiata (CR) down to the medulla. Results : The contralateral primary sensorimotor cortex (SM1) was mainly found to be activated in all subjects. DTT showed that tracts originated from SM1 and ran to the medulla along the known pathway of the CST. In all subjects, FA values of the CST were higher at the level of the midbrain and posterior limb of internal capsule (PLIC) than the level of others. Conclusion : Our study showed that co-registered fMRI and DTT has elucidated the state of CST on 3-D and analyzed the quantitative values of FA and ADC at the multiple levels. We conclude that co-registered fMRI and DTT may be applied as a useful tool for clarifying and investigating the state of CST in the patients with brain injury.

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