研究者データベース

富岡 智(トミオカ サトシ)
工学研究院 応用量子科学部門 量子生命工学
教授

基本情報

所属

  • 工学研究院 応用量子科学部門 量子生命工学

職名

  • 教授

学位

  • 博士(工学)(北海道大学)

ホームページURL

J-Global ID

研究キーワード

  • 加速器工学   数値電磁界解析   プラズマ理工学   Plasma Physics Numerical Analysis of Electromagnetics Accelerator Engineering   

研究分野

  • エネルギー / 原子力工学
  • 情報通信 / 計算科学
  • エネルギー / 核融合学

所属学協会

  • 応用物理学会   日本原子力学会   日本計算数理工学会   プラズマ・核融合学会   

研究活動情報

論文

  • Arata Hirokami, Samia Heshmat, Satoshi Tomioka
    Mathematics and Computers in Simulation 190 329 - 342 2021年12月 [査読有り]
  • Yuta Nakamura, Taisuke Takayanagi, Tomoki Uesaka, Mehmet Burcin Unlu, Yasutoshi Kuriyama, Yoshihiro Ishi, Tomonori Uesugi, Masanori Kobayashi, Nobuki Kudo, Sodai Tanaka, Kikuo Umegaki, Satoshi Tomioka, Taeko Matsuura
    Medical physics 48 9 5490 - 5500 2021年09月 
    PURPOSE: Ionoacoustics is one of the promising approaches to verify the beam range in proton therapy. However, the weakness of the wave signal remains a main hindrance to its application in clinics. Here we studied the potential use of a fixed-field alternating gradient accelerator (FFA), one of the accelerator candidates for future proton therapy. For such end, magnitude of the pressure wave and range accuracy achieved by the short-pulsed beam of FFA were assessed, using both simulation and experimental procedure. METHODS: A 100 MeV proton beam from the FFA was applied on a water phantom, through the acrylic wall. The beam range measured by the Bragg peak (BP)-ionization chamber (BPC) was 77.6 mm, while the maximum dose at BP was estimated to be 0.35 Gy/pulse. A hydrophone was placed 20 mm downstream of the BP, and signals were amplified and stored by a digital oscilloscope, averaged, and low-pass filtered. Time-of-flight (TOF) and two relative TOF values were analyzed in order to determine the beam range. Furthermore, an acoustic wave transport simulation was conducted to estimate the amplitude of the pressure waves. RESULTS: The range calculated when using two relative TOF was 78.16 ± 0.01 and 78.14 ± 0.01 mm, respectively, both values being coherent with the range measured by the BPC (the difference was 0.5-0.6 mm). In contrast, utilizing the direct TOF resulted in a range error of 1.8 mm. Fivefold and 50-fold averaging were required to suppress the range variation to below 1 mm for TOF and relative TOF measures, respectively. The simulation suggested the magnitude of pressure wave at the detector exceeded 7 Pascal. CONCLUSION: A submillimeter range accuracy was attained with a pulsed beam of about 21 ns from an FFA, at a clinical energy using relative TOF. To precisely quantify the range with a single TOF measurement, subsequent improvement in the measuring system is required.
  • Taisuke Takayanagi, Tomoki Uesaka, Yuta Nakamura, Mehmet Burcin Unlu, Yasutoshi Kuriyama, Tomonori Uesugi, Yoshihiro Ishi, Nobuki Kudo, Masanori Kobayashi, Kikuo Umegaki, Satoshi Tomioka, Taeko Matsuura
    Scientific Reports 10 20385  2020年12月 [査読有り]
     
    AbstractIn contrast to conventional X-ray therapy, proton beam therapy (PBT) can confine radiation doses to tumours because of the presence of the Bragg peak. However, the precision of the treatment is currently limited by the uncertainty in the beam range. Recently, a unique range verification methodology has been proposed based on simulation studies that exploit spherical ionoacoustic waves with resonant frequency (SPIREs). SPIREs are emitted from spherical gold markers in tumours initially introduced for accurate patient positioning when the proton beam is injected. These waves have a remarkable property: their amplitude is linearly correlated with the residual beam range at the marker position. Here, we present proof-of-principle experiments using short-pulsed proton beams at the clinical dose to demonstrate the feasibility of using SPIREs for beam-range verification with submillimetre accuracy. These results should substantially contribute to reducing the range uncertainty in future PBT applications.
  • Daichi Kando, Satoshi Tomioka, Naoki Miyamoto, Ryosuke Ueda
    Applied Science 9 17 3529-1 - 3529-13 2019年08月 [査読有り][通常論文]
     
    In an optical measurement system using an interferometer, a phase extracting technique from interferogram is the key issue. When the object is varying in time, the Fourier-transform method is commonly used since this method can extract a phase image from a single interferogram. However, there is a limitation, that an interferogram including closed-fringes cannot be applied. The closed-fringes appear when intervals of the background fringes are long. In some experimental setups, which need to change the alignments of optical components such as a 3-D optical tomographic system, the interval of the fringes cannot be controlled. To extract the phase from the interferogram including the closed-fringes we propose the use of deep learning. A large amount of the pairs of the interferograms and phase-shift images are prepared, and the trained network, the input for which is an interferogram and the output a corresponding phase-shift image, is obtained using supervised learning. From comparisons of the extracted phase, we can demonstrate that the accuracy of the trained network is superior to that of the Fourier-transform method. Furthermore, the trained network can be applicable to the interferogram including the closed-fringes, which is impossible with the Fourier transform method.
  • Daichi Kando, Satoshi Tomioka
    Electronic Imaging, Image Processing: Algorithms and Systems XVII 2019 11 259-1 - 259-5 2019年02月 [査読有り][通常論文]
  • Satoshi Tomioka, Shusuke Nishiyama, Yutaka Matsumoto, Naoki Miyamoto
    Engineering Analysis with Boundary Elements 106 493 - 504 2019年 [査読有り][通常論文]
  • Arata Hirokami, Satoshi Tomioka
    The 37th JSST Annual International Conference on Simulation Technology 109 - 112 2018年09月 [査読有り][通常論文]
  • 広上新, 富岡智
    電磁界理論研究会 118 67 17 - 22 2018年05月 [査読無し][通常論文]
  • W. Takado, Y. Matsumoto, K. Y. Watanabe, S. Tomioka, S. Oikawa
    PHYSICS OF PLASMAS 24 9 092506:1 - 7 2017年09月 [査読有り][通常論文]
     
    We studied the effects of the broken solenoidal condition of a magnetic field in linear magnetohydrodynamics (MHD) simulations based on a real coordinate system for Large Helical Device plasmas. Artificial errors of various orders in this condition were introduced into linear MHD simulations and compared. Spurious Fourier modes were observed to be dominant because of the error in the condition. We suggested a criterion, which is expressed as the condition that the ratio of the error force to the Lorentz force is much smaller than 100%, for estimating an acceptable limit of the solenoidal condition error through the simulation results. The effects of a large error in the condition of the analysis of a specified single-mode instability were investigated in addition. Adding a large error in the condition resulted in certain undesirable modes becoming dominant, whereas the desirable mode did not dominate. Thus, a large error in the condition can be harmful to analysis with a focus on specified modes. Published by AIP Publishing.
  • Satoshi Tomioka, Shusuke Nishiyama, Naoki Miyamoto, Daichi Kando, Samia Heshmat
    APPLIED OPTICS 56 24 6755 - 6764 2017年08月 [査読有り][通常論文]
     
    Interferometric tomography can reconstruct 3D refractive-index distributions through phase-shift measurements for different beam angles. To reconstruct a complex refractive-index distribution, many projections along different directions are required. For the purpose of increasing the number of the projections, we earlier proposed a beam-angle-controllable interferometer with mechanical stages; however, the quality of reconstructed distribution by conventional algorithms was poor because the background fringes cannot be precisely controlled. To improve the quality, we propose a weighted reconstruction algorithm that can consider projection errors. We demonstrate the validity of the weighted reconstruction through simulations and a reconstruction from experimental data for three candle flames. (C) 2017 Optical Society of America
  • 高堂 渉, 松本 裕, 渡邊 清政, 富岡 智, 及川 俊一
    日本物理学会講演概要集 72.2 132 - 132 一般社団法人 日本物理学会 2017年
  • W. Takado, Y. Matsumoto, K. Y. Watanabe, S. Tomioka, S. Oikawa
    PHYSICS OF PLASMAS 23 10 102509:1 - 5 2016年10月 [査読有り][通常論文]
     
    Here, the vector potential was introduced to a linear magnetohydrodynamics (MHD) simulation code, and the modified and original simulation results were compared. The effects of the broken solenoidal condition on the perturbed magnetic field in linear MHD simulations based on real coordinates were investigated. The results showed that the modified code can successfully remove the error in this condition, and the modified code was confirmed to work appropriately. Incorrect results can be yielded by an error in the condition, especially in analyses of the mode structure. Published by AIP Publishing.
  • Kazunori Zaima, Satoshi Tomioka, Koichi Sasaki
    JAPANESE JOURNAL OF APPLIED PHYSICS 54 8 088005:1 - 3 2015年08月 [査読有り][通常論文]
     
    We applied near-infrared cavity-ringdown absorption spectroscopy to a slender premixed burner flame with the intention of measuring the density of OH radicals. We found that the ringdown frequency was increased by the flame even when the laser wavelength was detuned from absorption lines. The additional ringdown frequency was dependent on the diameter of cavity mirrors, even though the expected spot size of the laser beam inside the cavity was much smaller than the mirror diameter. (C) 2015 The Japan Society of Applied Physics
  • Satoshi Tomioka, Shusuke Nishiyama, Samia Heshmat, Yasuhiro Hashimoto, Kodai Kurita
    COMPUTATIONAL IMAGING XIII 9401 0J01 - 0J10 2015年 [査読有り][通常論文]
     
    This paper presents a method to measure three-dimensional gas temperature distribution without inserting a probe into the gas using techniques of computed tomography and optical interferometry. The temperature distribution can be reconstructed from a set of two-dimensional optical difference images for which the incident angle of each distribution differs. The each optical difference is measured by an interferometer with four mirrors which are movable and rotatable to control the incident angle. The temperature measurement system has two kinds of errors. The first is the error in the reconstruction caused by the limited angle of projection; the direction of the incident angle is limited in a certain region because of the limited arrangements of mirrors. The second is the errors in an evaluation of the projection data, which is the two-dimensional optical difference distribution, which are included in steps to evaluate the optical difference; a carrier frequency detection of background fringe, a carrier component filtering, phase unwrapping and so on. This paper shows improvements of accuracy of the reconstruction by adding a certain projection data to the original data set, and also the improvements of the evaluation of the optical difference using newly developed algorithms to evluate the optical differences.
  • Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama
    INTERNATIONAL JOURNAL OF OPTOMECHATRONICS 8 4 260 - 274 2014年10月 [査読有り][通常論文]
     
    Phase unwrapping still plays an important role in the optical metrology field. The phase unwrapping process has direct influence on the accuracy of final results. The aim of this article is to evaluate the performance of several well-known phase unwrapping algorithms for noisy phase measurement. The results of the examined algorithms on simulated and real phase data are presented, and the conclusions regarding the performances of each studied algorithm are given.
  • Satoshi Tomioka, Shusuke Nishiyama, Samia Heshmat
    Applied Optics 53 25 5620 - 5631 2014年09月 [査読有り][通常論文]
     
    This paper presents a new method to obtain a wrapped phase distribution from a single interferogram with a spatial carrier modulation. The Fourier transform of the interferogram has three peaks: one is a dc peak around the origin in the Fourier domain, and the other two are carrier peaks that have information of phase modulation by an object placed in the interferometer. Since the wrapped phase can be evaluated by one of the two carrier peaks, the dc peak and the adjoint peak that is the other peak of two carrier peaks should be removed by filters. The proposed filtering process consists of two stages: dc peak filtering and adjoint peak filtering. A spectrum shift filter based on symmetrical characteristics of the spectrum is applied in both stages as a basic filter that can remove most of the undesired spectrum. An additional two filters are applied to remove the remaining spectrum. The new method can automatically isolate the carrier peak, even when the boundary of peaks is not very clear. Numerical evaluations of simulation data and experimental data demonstrate that the proposed method can successfully isolate the carrier peak. (C) 2014 Optical Society of America
  • Satoshi Tomioka, Shusuke Nishiyama
    IMAGE PROCESSING: ALGORITHMS AND SYSTEMS XII 9019 0M1 - 0M10 2014年 [査読有り][通常論文]
     
    In order to measure the optical distance of the object that changes rapidly over time, Fourier transform method is appropriate because it requires only a single interferogram. In the measurements of such fast phenomena, the thermal noise by the camera to record the interferogram results in a significant error and the signal becomes weak owing to the short exposure time of the camera. When the noise level is high, a process to denoise wrapped phase should be added before phase unwrapping in order to obtain an optical distance distribution. The thermal noise has a uniform spatial distribution; however, the signal depends on a profile of the incident wave to the interferometer. This means that the signal to noise ratio has a spatial distribution. This paper proposes the denoising method that can take account of the weight of the data that depends on the signal intensity distribution. In order to determine the denoised phase, two cost functions are examined. One is a complex-valued cost function that can ensure convergence of iterative method to obtain the stationary point; however, it is not proved that both the real part and the imaginary part are minimized at the stationary point. The other is a real-valued cost function that cannot ensure the convergence but it minimizes the cost function at the stationary point. The numerical simulation demonstrates the validity of the weighted denoising and the applicability of the cost functions.
  • Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama
    OPTICAL ENGINEERING 52 10 101910-1 - 8 2013年10月 [査読有り][通常論文]
     
    The growing interest in the applications of digital holography interferometry has led to an increasing demand for reliable phase unwrapping techniques. In digital holography, the phase carries three-dimensional surface information about the object. However, phase mapping is ambiguous as the extracted phase is returned in a form that suffers from 2 pi phase jumps. Furthermore, the presence of noise in the measured data, in which many singular points (SP) are found, often makes general phase unwrapping algorithms fail to produce accurate unwrapped results. Therefore, it is necessary to use a powerful phase unwrapping method to recover the desired smooth phase surface. For this reason, we developed a phase unwrapping algorithm that is applicable to digital hologram maps. The developed algorithm solves the singularity problem caused by SPs as a result of compensating its effect by using rotational and direct compensators. We show a difference in performance between our developed phase unwrapping algorithm and other well known phase unwrapping methods for digital holographic data. In addition, the methods to extract phase information of the object from hologram maps are also investigated. Results show that the developed algorithm gives satisfactory unwrapped results with low computational time cost. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License.
  • Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama
    FRINGE 2013 - 7th International Workshop on Advanced Optical Imaging and Metrology 155 - 160 2013年 [査読有り][通常論文]
  • Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama
    OPTICAL REVIEW 19 6 444 - 450 2012年11月 [査読有り][通常論文]
     
    Three-dimensional (3D) imaging continues to attract much research interest for its wide applications. In 3D shape measurement, the phase carries information about the object. However, phase mapping is ambiguous as the extracted phase is returned in a form that suffers from 2 pi phase jumps. In this case, the phase data must be unwrapped to be fit for use. Furthermore, sometimes the presence of noise in the measured data, in which many singular points (SPs) are found, makes general phase unwrapping algorithms fail to produce accurate unwrapped results. For this reason, we propose a new phase unwrapping method for dynamic 3D shape measurement. The new algorithm is based on compensating the singularity of discontinuity sources. It uses direct compensators for adjoining SP pairs and uses rotational compensators for other SP pairs. The proposed algorithm has been evaluated and compared with past phase unwrapping methods. Results show that the proposed method gives satisfactory unwrapped results with a low computation time.
  • Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama
    Speckle 2012: V International Conference on Speckle Metrology 2012年09月11日 [査読有り]
  • TOMIOKA Satoshi
    Applied Optics 51 21 4984 - 4994 2012年07月 [査読有り][通常論文]
     
    Phase unwrapping for a noisy image suffers from many singular points. Singularity-spreading methods are useful for the noisy image to regularize the singularity. However, the methods have a drawback of distorting phase distribution in a regular area that contains no singular points. When the singular points are confined in some local areas, the regular region is not distorted. This paper proposes a new phase unwrapping algorithm that uses a localized compensator obtained by clustering and by solving Poisson's equation for the localized areas. The numerical results demonstrate that the proposed method can improve the accuracy compared with other singularity-spreading methods. (C) 2012 Optical Society of America
  • Satoshi Tomioka, Shusuke Nishiyama
    COMPUTATIONAL IMAGING X 8296 17_1 - 9 2012年 [査読有り][通常論文]
     
    This study presents a nondestructive three-dimensional (3D) measurement of gas temperature distribution around a heater. The distribution is obtained by a coupling method of optical interferometry and computed tomography (CT). Since the gas temperature is related to refractive index, once a series of two-dimensional (2D) phase modulation that is an integral of refractive index along an optical path is obtained, the 3D gas temperature distribution can be ideally determined in the same way as the widely-used CT to determine a distribution of attenuation factor. However, the series of 2D phase images is not complete; phase images from certain directions cannot be obtained because of limitations of the measurement system. Furthermore, the 2D images of phase modulation are not observed directly, since the interferometer can only detect a 2D image of intensity distribution called fringe pattern. To retrieve the phase modulation from the fringe pattern, both digital holography and phase unwrapping algorithm are applied. To obtain 3D gas temperature distributions with such incomplete data sets, we apply a method using localized compensator for phase unwrapping algorithm to obtain 2D modulation maps, and a maximum-likelihood tomography for a 3D reconstruction. Accuracy of each method is compared with that of conventional methods.
  • HESHMAT Samia, TOMIOKA Satoshi, NISHIYAMA Shusuke
    Applied Optics 50 33 6225 - 6233 2011年11月 [査読有り][通常論文]
     
    Phase unwrapping still plays an important role in many data-processing chains based on phase information. Here, we introduce a new phase unwrapping approach for noisy wrapped phase maps of continuous objects to improve the accuracy and computational time requirements of phase unwrapping using a rotational compensator (RC) method. The proposed algorithm is based on compensating the singularity of discontinuity sources. It uses direct compensation for adjoining singular point (SP) pairs and uses RC for other SP pairs. The performance of the proposed method is tested through both simulated and real wrapped phase data. The proposed algorithm is faster than the original algorithm with the RC and has proved efficiency compared to other phase unwrapping methods. (C) 2011 Optical Society of America
  • TOMIOKA Satoshi, HESHMAT Samia, MIYAMOTO Naoki, NISHIYAMA Shusuke
    Applied Optics 49 25 4735 - 4745 2010年09月 [査読有り][通常論文]
     
    In the process of phase unwrapping for an image obtained by an interferometer or in-line holography, noisy image data may pose difficulties. Traditional phase unwrapping algorithms used to estimate a two-dimensional phase distribution include much estimation error, due to the effect of singular points. This paper introduces an accurate phase-unwrapping algorithm based on three techniques: a rotational compensator, unconstrained singular point positioning, and virtual singular points. The new algorithm can confine the effect of singularities to the local region around each singular point. The phase-unwrapped result demonstrates that accuracy is improved, compared with past methods based on the least-squares approach. (c) 2010 Optical Society of America
  • Satoshi Tomioka, Shusuke Nishiyama
    ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS 34 4 393 - 404 2010年04月 [査読有り][通常論文]
     
    This paper presents a gradient field representation using an analytical regularization of a hypersingular boundary integral equation for a two-dimensional time harmonic wave equation called the Helmholtz equation. The regularization is based on cancelation of the hypersingularity by considering properties of hypersingular elements that are adjacent to a singular node. Advantages to this regularization include applicability to evaluate cornet nodes, no limitation for element size, and reduced computational cost compared to other methods. To demonstrate capability and accuracy, regularization is estimated for a problem about plane wave propagation As a result. it is found that even at a corner node the most. significant error in the proposed method is due to truncation error of non-singular elements in discretization, and error from hypersingular elements is negligibly small. (C) 2009 Elsevier Ltd. All rights reserved.
  • Satoshi Tomioka, Tamotsu Kozaki, Hidenori Takamatsu, Natsuko Noda, Shusuke Nisiyama, Naofumi Kozai, Satoru Suzuki, Seichi Sato
    APPLIED CLAY SCIENCE 47 1-2 65 - 71 2010年01月 [査読有り][通常論文]
     
    Compacted bentonite, of which the major clay mineral is montmorillonite, is a candidate buffer material for geological disposal of high-level radioactive waste. In this study, a microfocus X-ray computed tomography (micro-CT, X-ray microscope), which enables non-destructive, three-dimensional observation of the interior microstructure of a sample with high resolution (several microns), examined compacted montmorillonite samples under dry and water-saturated states. The images thus obtained were analyzed by a computer code developed for this study to obtain the information on the size and shape of montmorillonite grains in the samples before and after the water saturation. From the results of the image analysis, it can be supposed that the outer montmorillonite sheets of grains swelled and formed a gel, whereas the inner montmorillonite sheets did not change significantly in the water-saturation process. (C) 2008 Elsevier B.V. All rights reserved.
  • Kazuhiro Fujita, Hideki Kawaguchi, Thomas Weiland, Satoshi Tomioka
    IEEE TRANSACTIONS ON NUCLEAR SCIENCE 56 4 2341 - 2350 2009年08月 [査読有り][通常論文]
     
    We present time domain 3-D wake field calculations based on Scattered-field Time Domain Boundary Element Method (S-TDBEM), which is retarded Kirchhoff's boundary integral equations of scattered electromagnetic fields formulated on interior region problem and has no numerical dispersion in all spatial direction. We propose two main types of S-TDBEM schemes: full 3-D scheme for general 3-D geometries and a so-called 2.5-D scheme for transverse wake field calculation in axis-symmetric structures. Several numerical examples are demonstrated for typical accelerator structures: elliptical pillbox and the TESLA 9-cell cavities. The developed 3-D/2.5-D S-TDBEM codes are verified by comparison with the modal analysis and the finite integration technique (FIT) in the numerical examples. Finally, as one of the most meaningful applications of the S-TDBEM, we demonstrate wake field simulations of a curved trajectory bunch with the developed 3-D S-TDBEM code.
  • T. Kamiyama, N. Miyamoto, S. Tomioka, T. Kozaki
    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 605 1-2 91 - 94 2009年06月 [査読有り][通常論文]
     
    Neutron resonance absorption spectroscopy (N-RAS) with a pulsed neutron source can distinguish the dynamics of individual nuclides having resonance peaks on epithermal neutron region. The analyzed internal information of nuclide presence and its effective temperature can be reconstructed as distributions over the object cross-section using computed tomography (CT). Because some of the resonance absorption cross-sections have very large values, N-RAS could match the small neutron pulsed source by its high sensitivity. In this study, we have constructed a new instrument of N-RAS on a compact electron linac neutron source. Resonance absorption measurements and CT imaging with the instrument have succeeded for some kinds of nuclide. (C) 2009 Elsevier B.V. All rights reserved.
  • Kiyanagi Yoshiaki, Kamiyama Takashi, Takada Osamu, Morita Keigo, Iwase Kenji, Suzuki Shun, Furusaka Michihiro, Hiraga Fujio, Tomioka Satoshi, Mishima Kaichiro, Takenaka Nobuyuki, Ino Takashi
    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 600 1 167 - 169 2009年02月21日 [査読有り][通常論文]
  • Takashi Kamiyama, Naoki Miyamoto, Satoshi Tomioka, Tamotsu Kozaki
    IEEE Nuclear Science Symposium Conference Record 1266 - 1270 2009年 [査読有り][通常論文]
     
    Neutron resonance absorption spectroscopy (N-RAS) with a pulsed neutron source can distinguish the dynamics of individual nuclides which have neutron resonance peaks on epithermal neutron region. Because some of the resonance absorption cross sections have very large values, N-RAS could match the small neutron pulse source by its high sensitivity. The analyzed spectra information of nuclide presence and its effective temperature can be reconstructed as distributions over the object cross-section using computer tomography (CT). In this study the projected nuclide densities were obtained from the resonance absorption equation fitting with the series of obtained spectra. Then, we reconstructed the quantitative nuclide density tomogram using the CT technique about them. ©2009 IEEE.
  • T. Kamiyama, N. Miyamoto, S. Tomioka, T. Kozaki
    2009 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-5 1266 - + 2009年 [査読有り][通常論文]
     
    Neutron resonance absorption spectroscopy (N-RAS) with a pulsed neutron source can distinguish the dynamics of individual nuclides which have neutron resonance peaks on epithermal neutron region. Because some of the resonance absorption cross sections hale very large values, N-RAS could match the small neutron pulse source by its high sensitivity. The analyzed spectra information of nuclide presence and its effective temperature can he reconstructed as distributions over the object cross-section using computer tomography (CT). In this study the projected nuclide densities were obtained from the resonance absorption equation fitting with the series of obtained spectra. Then, we reconstructed the quantitative nuclide density tomogram using the CT technique about them.
  • Kazuhiro Fujita, Hideki Kawaguchi, Robert Hampel, Wolfgang F. O. Mueller, Thomas Weiland, Satoshi Tomioka
    IEEE TRANSACTIONS ON NUCLEAR SCIENCE 55 5 2584 - 2591 2008年10月 [査読有り][通常論文]
     
    We present an explicit Time Domain Boundary Element Method (TDBEM) scheme with moving window technique for short-range wake field simulations of long accelerator structures. The proposed scheme is formulated by Kirchhoff's boundary integral equation of the scattered electromagnetic field in interior region problems. Implementation of a moving window technique in the framework of TDBEM is achieved by taking into account the causality and the retardation properties of the boundary integral equation. A parallelization algorithm for this moving window implementation is also proposed. The proposed TDBEM code with the moving window technique is applied to several practical examples of long accelerator structures. Numerical results obtained with the TDBEM code are compared with those of several finite integration codes.
  • Moving Window技術を用いた時間領域境界要素法による粒子加速器航跡場の大規模並列計算
    藤田和広, 川口秀樹, 富岡智
    信学技報 107 1, EMT2007-2 7 - 12 2007年08月 [査読無し][通常論文]
  • Naoki Miyamoto, Shusuke Nisiyama, Satoshi Tomioka, Takeaki Enoto
    OPTICS COMMUNICATIONS 272 1 67 - 72 2007年04月 [査読有り][通常論文]
     
    We utilize nitroanisole, that absorbs infrared (IR) radiation as heat, as an optical modulation device based on a thermal process. The nitroanisole exhibits a thermal lens effect, i.e. a temperature dependent refractive index. Hence, the nitroanisole can induce phase modulation to visible light, in direct response to intensity of the incident IR radiation. The proposed method can be used to obtain the phase modulation distribution that corresponds to the IR intensity distribution, i.e. the IR hologram itself, on the nitroanisole by examining the phase map of visible light that is modulated upon passing through the nitroanisole. The IR wavefront can be reconstructed by calculating extracted IR holograms through the Fresnel transform. It is verified that both the amplitude and the phase of the IR wavefront can be reconstructed accurately by proposed method. (c) 2006 Elsevier B.V. All rights reserved.
  • Kazuhiro Fujita, Hideki Kawaguchi, Shusuke Nishiyama, Satoshi Tomioka, Takeaki Enoto, Igor Zagorodnov, Thomas Weiland
    IEICE TRANSACTIONS ON ELECTRONICS E90C 2 265 - 274 2007年02月 [査読有り][通常論文]
     
    Authors have been working in particle accelerator wake field analysis by using the Time Domain Boundary Element Method (TDBEM). A stable TDBEM scheme was presented and good agreements with conventional wake field analysis of the FDTD method were obtained. On the other hand, the TDBEM scheme still contains difficulty of initial value setting on interior region problems for infinitely long accelerator beam pipe. To avoid this initial value setting, we adopted a numerical model of beam pipes with finite length and wall thickness on open scattering problems. But the use of such finite beam pipe models causes another problem of unwanted scattering fields at the beam pipe edge, and leads to the involvement of interior resonant solutions. This paper presents a modified TDBEM scheme, Scattered-field Time Domain Boundary Element Method (S-TDBEM) to treat the infinitely long beam pipe on interior region problems. It is shown that the S-TDBEM is able to avoid the excitation of the edge scattering fields and the involvement of numerical instabilities caused by interior resonance, which occur in the conventional TDBEM.
  • Satoshi Tomioka, Shusuke Nisiyama, Takeaki Enoto
    IEEE TRANSACTIONS ON EVOLUTIONARY COMPUTATION 11 1 1 - 16 2007年02月 [査読有り][通常論文]
     
    In conventional least square (LS) regressions for nonlinear problems, it is not easy to obtain analytical derivatives with respect to target parameters that comprise a set of normal equations. Even if the derivatives can be obtained analytically or numerically, one must take care to choose the correct initial values for the iterative procedure of solving an equation, because some undesired, locally optimized solutions may also satisfy the normal equation. In the application of genetic algorithms (GAs) for nonlinear LS, it is not necessary to use normal equations, and a GA is also capable of avoiding localized optima. However, convergence of population and reliability of solutions depends on the initial domain of parameters, similarly to the choice of initial values in the abovementioned method using the normal equation. To overcome this disadvantage of applying GAs for nonlinear LS, we propose to use an adaptive domain method (ADM) in which the parameter domain can change dynamically by using several real-coded GAs with short lifetimes. Through an example problem, we demonstrate improvements in terms of both the convergence and the reliability by ADM. A further merit in the proposed method is that it does not require any specialized knowledge about GAs or their tuning. Therefore, the nonlinear LS by ADM with GAs are accessible to general scientists for various applications in many fields.
  • K. Fujita, R. Hampel, W. F. O. Mueller, T. Weiland, H. Kawaguchi, S. Tomioka, T. Enoto
    2007 IEEE PARTICLE ACCELERATOR CONFERENCE, VOLS 1-11 1549 - + 2007年 [査読有り][通常論文]
     
    This paper introduces a new explicit scheme with a moving window option for wake field calculation of long accelerator structures. This scheme is based on a time domain boundary element method (TDBEM) which uses a retarded Kirchhoff boundary integral equation for interior region problems. As a corollary of this boundary integral equation, our approach allows a conformal modeling of a structure and time domain wake field simulation without numerical grid dispersion errors in all spatial directions. The implementation of a moving window technique in the framework of TDBEM is presented and it is shown that this moving window technique allows to significantly reduce memory requirement of the TDBEM scheme in the short range wake field calculation. Several numerical examples are demonstrated for the TESLA 9-cell cavity and tapered collimators. The results of the new TDBEM scheme are compared with those of finite difference codes.
  • N Miyamoto, S Nisiyama, S Tomioka, T Enoto
    OPTICS COMMUNICATIONS 260 1 25 - 29 2006年04月 [査読有り][通常論文]
     
    We propose the application of nitroanisole as a detector for middle infrared (mid-IR) interferometry or holography. The present experiment utilizes the liquid form of nitroanisole, which has a thermal lens effect. i.e. a temperature dependent refractive index. Since the nitroanisole absorbs IR radiation as heat, it is possible to estimate the IR intensity distribution on the nitroanisole from the diffraction pattern made by visible laser light that is transmitted through the nitroanisole. In this study, the time resolution and the diffraction efficiency of the nitroanisole was measured under various conditions. The experimental results show that the nitroanisole has a time resolution as high as that of a standard video camera, as well as a high diffraction efficiency and the spatial resolution equivalent to that of a conventional IR camera. Furthermore, we confirmed that the phase shift in mid-IR region can be estimated by analyzing the change in the visible diffraction pattern. (c) 2005 Elsevier B.V. All rights reserved.
  • Naoki Miyamoto, Shusuke Nisiyama, Satoshi Tomioka, Takeaki Enoto
    Proceedings of SPIE - The International Society for Optical Engineering 6049 0O.01 - 0O.10 2005年 [査読有り][通常論文]
     
    We propose the application of nitroanisole as a two-dimensional detector for infrared (IR) phase-shifting interferometry. The nitroanisole that is utilized in our experiment is liquid at room temperature and it has significant thermal lens effect, i.e. the refractive index for visible light is dependent on temperature. In addition, we verified by infrared absorption spectroscopy that the nitroanisole has an absorption band around 10.6μm in the IR region. Therefore, the interference fringe pattern that is generated on the nitroanisole by the IR beams may be treated as a phase grating for visible light. A Fresnel diffraction pattern made by visible laser light that is transmitted through the phase grating, i.e. the nitroanisole, can be observed as a superposition of the intensities corresponding to the profile of the phase grating and its harmonic components. Additionally, in response to a shift of the interference fringe on the nitroanisole, the Fresnel diffraction pattern on the observation plane also shifts by an equal amount. Utilizing this characteristic of nitroanisole, we attempted to estimate the IR phase map by applying the phase-shifting method to the diffraction patterns. We conducted an experiment aimed to measure the angle of a wedge of ZnSe, which is an IR transmitting material, and we confirmed the feasibility of obtaining phase measurements in the IR region by this procedure.
  • Identification of Electromagnetic Mode Excited by Electron Beam in Waveguide using Genetic Algorithm
    S. Tomioka, S. Nisiyama, T. Enoto
    Computational Engineering I, --- Advances in Continuum Mechanics and Electro Magnetics ---, Japan Society for Computational Methods in Engineering 251 - 260 2004年 [査読有り][通常論文]
  • Y Ito, Y Katoh, M Kagata, S Nisiyama, S Tomioka, T Enoto
    25TH INTERNATIONAL CONGRESS ON HIGH-SPEED PHOTOGRAPHY AND PHOTONICS 4948 739 - 744 2003年 [査読有り][通常論文]
     
    Ultra high-speed X-ray framing cameras have improved considerably in recent years. Frames with temporal resolution of less than 100 ps are achievable, due to application of the non-linear amplification properties a microchannel plate (MCP). However, in the case of frame resolution under 100 ps, the propagation delay of the shuttering pulse on the MCP poses a significant problem to the maintenance of simultaneity of gated images. In the present research, a method to augment the simultaneity of images is presented. In previous designs, the photocathode was coated onto the MCP input surface. The improved design presented here separates the photocathode from the MCP detector. The transit time of the photoelectrons is varied at each point on the gated electrode is with respect to the MCP detector. Results show that the simultaneity of images is improved with this new design.
  • Atsushi Ota, Satoshi Tomioka, Shusuke Nisiyama, Takeaki Enoto
    Inverse Problems in Engineering Mechanics IV 389 - 398 2003年 [査読有り][通常論文]
     
    This chapter discusses an inverse analysis for the sake of a non-destructive estimation system for a measurement of an inhomogeneous distribution of plasma by scattering field. The inverse analysis is based on two techniques: (1) multi-layered Neural networks (NN) to solve inverse problem, and (2) a boundary element method to solve a direct problem to generate learning data for the NN. In the case of an analysis using simple technique, the learning procedure in NN did not have a good convergence. Hence, two techniques to improve the convergence are proposed: (1) the normalization technique for the input data with consideration of the distribution of amplitude of the input data, and (2) the dividing section technique. It is clarified that combination of these techniques provides a rapid convergence, and leads to the availability of the estimation system. © 2003 Elsevier B.V. All rights reserved.
  • 相対論的電子ビーム断面形状推定のための並列遺伝的アルゴリズムによる逆問題解析
    富岡 智, 西山 修輔, 榎戸 武揚
    計算数理工学論文集 1 33 - 38 2001年07月 [査読有り][通常論文]
  • Y Katoh, Y Ito, N Tomonura, S Tomioka, T Enoto
    24TH INTERNATIONAL CONGRESS ON HIGH-SPEED PHOTOGRAPHY AND PHOTONICS 4183 209 - 216 2001年 [査読有り][通常論文]
     
    In the scanning detector we propose the new system for improving spatial resolution by making sensitivity distribution of a detecting element vary. This can be simply done by only adding the filter with sensitivity distribution in front of a detecting element without requiring the higher density of equipment. In our laboratory, the plasma electron density distribution measurement by the holographic interferometry in far-infrared region has been proceeded. As one of the infrared detection material, we chose HgCdTe, and it was used as a scanning detecting element. As a. verification of this system, we added the infrared filter in the front of HgCdTe, and measured the spatial resolution using a knife edge. For the method for calculating Modulation Transfer Function (MTF) from Edge Response Function (ERF), we also propose the new technique that we name the virtual test chart method. In this technique, we simulates the response corresponded to periodic bar patterns from ERF, and calculates the contrast ratio from this response. From the result of measurement that added the infrared ray filter, the validity of this system was shown. By the simulation and the experiment, the optimum sensitivity distribution was obtained in this system.
  • S Nisiyama, S Tomioka, T Enoto
    INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS 14 1-4 243 - 247 2001年 [査読有り][通常論文]
     
    In this paper, a scattered field Finite-Difference Time-Domain (FD-TD) method is applied to wake-fields computation. In the ordinary FD-TD method or other methods based on the finite difference scheme, the trajectory of a traveling charged particle beam should be along the spatial grid. In the presented method, an arbitrary beam trajectory can be treated since the beam current is not placed on the spatial grid but is considered as an incident field source. Wake potentials of a simple system with a slightly angled beam trajectory are calculated for a demonstration.
  • Y Ito, Y Katoh, M Kagata, S Tomioka, T Enoto
    24TH INTERNATIONAL CONGRESS ON HIGH-SPEED PHOTOGRAPHY AND PHOTONICS 4183 193 - 200 2001年 [査読有り][通常論文]
     
    We propose a method to improve the shuttering characteristics of an ultra high-speed camera that consists of a proximity focused image intensifier (PFII) with an external transparent electrode (ETE). When the shuttering time of several tens of picoseconds is considered, the time delay by the propagation of the shuttering pulse can not be disregarded, and this time delay causes the problems in the system's simultaneity. First, the time of which the image was recorded is different by the place. Second, the time in which the photoelectron reaches the micro channel plate (MCP) input surface is different. For our research, the second problem mentioned above poses an obstacle. To utilize the nonlinear operation of the MCP for smaller gating time, it is necessary that each electron reaches the MCP in same time. Our proposal is to compensate for this second problem by controlling the electric field between the photocathode and the MCP. This is achieved by optimizing the shape of the electrode of the ETE. We show that the variance of arrival time is reduce from 30ps to 5ps using numerical analysis by FDTD method.
  • S Tomioka, S Nisiyama, T Enoto
    INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS 14 1-4 215 - 219 2001年 [査読有り][通常論文]
     
    For the purpose of non-destructive measurement of the cross-sectional shape of an electron beam, we have studied a detection system that is composed of both a number of antennas and a current monitor. The antenna detects an electric field, and the current monitor detects an integral of beam currents. The signals acquired from these detectors are applied as the input of an inverse problem. We adopt the genetic algorithm to simulate the profile measurement as an inverse problem analysis. The results showed that this detection system is partially effective, even though this system is an "ill-posed problem" (i.e. the number of input data parameters is less than the number of parameters to be estimated). We also found that the current monitor, which cannot acquire position-dependent information, is nevertheless useful to accelerate the convergence of sub-optimal beam profiles.
  • S Nisiyama, S Tomioka, T Enoto
    IEEE TRANSACTIONS ON MAGNETICS 36 4 888 - 891 2000年07月 [査読無し][通常論文]
     
    In this paper, me show a finite-difference time-domain (FD-TD) analysis of scattered fields excited by a pulsed beam using point charge responses and convolution. The advantages of this approach are easy handling of arbitrary beam trajectories and waveforms; efficient absorption for excited fields on open boundaries; and small amount of incident field calculation, In addition, we describe the relation between the temporal resolution and the allowable aliasing error since the point charge held as an incident field has very high frequency spectrum.
  • Dual Holographic Interferometry using Nitrobenzene as FIR Phase Detector
    Yoshinori Tsuji, Takeshi Harayama, Keiichi Nomura, Satoshi Tomioka, Takeaki Enoto
    Proc. for Symposium on Advanced Research of Energy Technology 2000 251 - 258 2000年03月 [査読無し][通常論文]
  • Y. Ito, Y. Katoh, M. Kagata, S. Tomioka, T. Enoto
    IEEE Transactions on Magnetics 36 4 1769 - 1773 2000年 [査読有り][通常論文]
     
    We suggest a method to improve the shuttering characteristics of an ultra high-speed camera that consists of a proximity focused image intensifier with a micro channel plate (MCP) and an external transparent electrode (ETE). Over a range of the gating times of the several tens of picoseconds, using this apparatus, there are two obstacles to the system's simultaneity, i.e., accuracy of photographing phenomena. First, the time required for the shuttering pulse to propagate on the electrode creates a time delay between different areas of the image photons passing through the ETE. Second, the photoelectrons do not reach the MCP simultaneously. If we attempt to speed-up the gating time using nonlinear operation of the MCP, the latter problem has an undesirable effect on the resulting image. Our proposal is to compensate for the latter problem and improve the simultaneity of the arrival time of photoelectrons at the MCP input surface by controlling the electric field between the photocathode and the MCP. This is achieved by optimizing the shape of the electrode. Further analysis by FDTD and an electron trajectory tracking method verified that the variance of arrival time is reduced from 30 ps to 5 ps with the altered electrode shape. © 2000 IEEE.
  • Improvement of Temporal Characteristics of Ultra High Speed Framing Camera for Measurement of LINAC Electron Beam
    Yoshihiro Ito, Nobuhisa Tonomura, Yasuto Katoh, Makoto Kagata, Satoshi Tomioka, Takeaki Enoto
    Proc. of the 24th Linear Accelerator Meeting in Japan 401 - 403 1999年07月 [査読無し][通常論文]
  • M Itagaki, S Nisiyama, S Tomioka, T Enoto
    JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY 36 3 273 - 281 1999年03月 [査読有り][通常論文]
     
    An advanced boundary element formulation has been proposed to solve the neutron diffusion equation (NDE) for a 'nonuniform' system. The continuous spatial distribution of a nuclear constant is assumed to he described using a polynomial function, Part of the constant term in the polynomial is left on the left-hand-side of the NDE, while the remainding is added to the fission source term on the right,hand-side to create a fictitious source. When the neutron flux is also expanded using a polynomial, the boundary integral equation corresponding to the NDE contains a domain integral related to the polynomial source. This domain integral is transformed into an infinite series of boundary integrals, by repeated application of the particular solution for a Poisson-type equation with the polynomial source. In two-dimensional, one-group test calculations for rectangular domains, the orthogonality of Legendre polynomials was used to determine the polynomial expansion coefficients. The results show good agreement with those obtained from finite difference computations in which the nonuniformity was approximated by a large number of material regions.
  • ニトロベンゼンを赤外線の位相情報検出材料として用いた2段ホログラフィー干渉法
    榎戸 武揚, 富岡 智, 原山 武志, 森部 英征
    機能材料 19 3 39 - 47 1999年02月 [査読有り][通常論文]
  • Satoshi Tomioka, Shusuke Nisiyama, Masafumi Itagaki, Takeaki Enoto
    Engineering Analysis with Boundary Elements 23 3 211 - 222 1999年01月 [査読有り][通常論文]
  • A Harmonics Selective Slot Antenna for Beam Position Monitor
    Shusuke Nisiyama, Kenta Itoh, Hiroyasu Itoh, Satoshi Tomioka, Takeaki Enoto
    Proc. of the 23rd Linear Accelerator Meeting in Japan 181 - 183 1998年09月 [査読無し][通常論文]
  • 定在波測定を用いる電子ビーム微細構造パルス幅の計測
    伊藤 裕康, 加賀田 誠, 西山 修輔, 富岡 智, 榎戸 武揚
    プラズマ・核融合学会誌 74 1 29 - 37 1998年01月 [査読有り][通常論文]
  • A New Estimate Method of Micro-pulse Width Using Standing Wave Measurement.
    H. Itoh, S. Nisiyama, N. Ishii, S. Tomioka, T. Enoto
    Proc. 11th Symp. on Accelerator Science and Technology 415 - 417 1997年10月 [査読無し][通常論文]
  • M Itagaki, S Nishiyama, S Tomioka, T Enoto, N Sahashi
    ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS 20 2 113 - 121 1997年09月 [査読有り][通常論文]
     
    The multiple reciprocity boundary element method (MRBEM) has been employed to solve the three-dimensional Helmholtz equation, del(2) phi + k(2) phi = 0. In the present technique, the Helmholtz equation is arranged as del(2) phi + k(0)(2) phi + phi/lambda = 0, where k(0) is an estimate of k and lambda is equal to (k(2) - k(0)(2))(-1). As the term phi/lambda is treated as a source, the power iteration technique with Wielandt's spectral shift is used to find the value of X. The boundary integral equation is formulated with the fundamental solution to del(2) phi + k(0)(2) phi + delta(i) = 0. The domain integral related to the above source is transformed into a series of boundary integrals, with the aid of the higher order fundamental solutions based on the spherical Bessel functions. The eigenvalue k(2) can also be described using only boundary integrals. Test calculations demonstrate that the present technique is efficient for finding k(2) and easier to handle than the conventional determinant search scheme. (C) 1997 Elsevier Science Ltd.
  • M Itagaki, S Tomioka, S Nisiyama, T Enoto
    ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS 20 1 63 - 71 1997年07月 [査読有り][通常論文]
     
    The zero-order and the higher-order fundamental solutions for the 3-D two-group neutron diffusion equations have been derived in such a way that these solutions satisfy the first and the second group equations simultaneously. Each degree of the solutions has a 2 x 2 matrix form based on two types of function, r(p) exp(-iBr) and r(p) exp(-kr). Singularities of type (1/r) are only found at the diagonal components of the zero-order solutions; however, no singularities are found at any components of the higher-order solutions. These solutions can be used for applying the multiple reciprocity boundary element method to 3-D two-group neutron diffusion problems. (C) 1997 Elsevier Science Ltd.
  • 加賀田 誠, 富岡 智, 榎戸 武揚
    電気学会論文誌 117-A 1 22 - 28 1997年01月 [査読有り][通常論文]
  • 電子ビームによって形成される電磁界のスペクトル解析(II)
    伊藤 裕康, 西山 修輔, 石田 崇, 富岡 智, 榎戸 武揚
    Proc. of the 21st Linear Accelerator Meeting in Japan 340 - 342 1996年09月 [査読無し][通常論文]
  • S Nisiyama, S Tomioka, M Kagata, H Itoh, T Enoto
    BOUNDARY ELEMENT METHODS 319 - 326 1996年 [査読無し][通常論文]
  • 電磁界問題の境界要素法における薄い金属板に関する一考察
    西山 修輔, 富岡 智, 加賀田 誠, 伊藤 裕康, 榎戸 武揚
    境界要素法論文集 12 23 - 26 1995年12月 [査読有り][通常論文]
  • 富岡 智, 加賀田 誠, 伊藤 裕康, 西山 修輔, 榎戸 武揚
    電気学会論文誌A 115 11 1098 - 1104 1995年11月 [査読有り][通常論文]
  • ビーム近傍におけるスロットアンテナの数値解析
    西山 修輔, 伊藤 裕康, 富岡 智, 榎戸 武揚
    Proceedings of the 20th Linear Accelerator Meeting in Japan 248 - 250 1995年09月 [査読無し][通常論文]
  • 境界要素法における二次元波動方程式の解の安定性について
    富岡 智, 西山 修輔, 加賀田 誠, 伊藤 裕康, 榎戸 武揚
    境界要素法研究会 第45回例会 1 - 23 1995年03月 [査読無し][通常論文]
  • 富岡 智, 加賀田 誠, 伊藤 裕康, 榎戸 武揚
    電気学会論文誌A 115 1 9 - 16 1995年01月 [査読有り][通常論文]
  • 境界要素法による不均質な波数を有するヘルムホルツ方程式の近似解法
    富岡 智, 加賀田 誠, 伊藤 裕康, 榎戸 武揚
    境界要素法論文集 11 83 - 88 1994年12月 [査読有り][通常論文]
  • 富岡 智, 加賀田 誠, 伊藤 裕康, 榎戸 武揚
    電気学会論文誌. A, 基礎・材料・共通部門誌 = The transactions of the Institute of Electrical Engineers of Japan. A, A publication of Fundamentals and Materials Society 115 1 9 - 16 電気学会 1994年12月 [査読有り][通常論文]
  • Spectrum Analysis of an Electromagnetic Field Generated by LINAC Electron Beams
    Hiroyasu Itoh, Shusuke Nisiyama, Satoshi Tomioka, Takeaki Enoto
    Proceedings of the 1994 International Linac Conference 860 - 862 1994年08月 [査読無し][通常論文]
  • スロットアンテナを用いた電子ライナックのビーム位置モニタ
    西山 修輔, 伊藤 裕康, 富岡 智, 榎戸 武揚
    Proceedings of the 19th Linear Accelerator Meeting in Japan(JAERI-Conf 94-03) 254 - 256 1994年07月 [査読無し][通常論文]
  • An experimental and analytical study of high speed shuttering characteristics of proximity focused image intensifiers
    B. D. Landberg, M. Kagata, S.Tomioka, T. Enoto, I. Fukai
    Int. J. of Applied Electromagnetics in Materials 5 377 - 380 1994年01月 [査読有り][通常論文]
  • Numerical analysis of ultra high-speed shuttering characteristics using finite-difference time-domain method
    M. Kagata, B. D. Landberg, S.Tomioka, T. Enoto, I. Fukai
    Int. J. of Applied Electromagnetics in Materials 5 381 - 384 1994年01月 [査読有り][通常論文]
  • Removing spurious solutions in boundary elemental method for multimedia problems using virtual boundary dividing method
    S.Tomioka, T. Enoto, I. Fukai
    Int. J. of Applied Electromagnetics in Materials 5 357 - 360 1994年01月 [査読有り][通常論文]
  • 富岡 智, 榎戸 武揚
    電気学会論文誌A 113 8 572 - 579 1993年08月 [査読有り][通常論文]
  • 電子ビームにより円筒導波管内に形成される電磁界の周波数解析
    伊藤裕康, 富岡智, 榎戸武揚
    Proceedings of the 18th Linear Accelerator Meeting in Japan 288 - 291 1993年07月 [査読無し][通常論文]
  • スロットアンテナによる電子ビーム測定とその過渡解析
    伊藤 裕康, 富岡 智, 榎戸 武揚
    Proc. on 17th Linear Accelerator Meeting in Japan 207 - 209 1992年09月 [査読無し][通常論文]
  • スロットアンテナを用いた電子ビーム周囲電界の測定
    伊藤裕康, 三浦広土, 富岡智, 榎戸武揚
    電気関係学会北海道支部連合大会 426 - 427 1991年10月 [査読無し][通常論文]
  • スロットアレイアンテナを用いた電子ビーム周囲電界測定
    三浦 広土, 富岡 智, 伊藤 裕康, 榎戸 武揚
    Proc. of the 16th Linear Accelerator Meeting in Japan 263 - 265 1991年09月 [査読無し][通常論文]
  • プラズマを含むファブリ・ペロー共振器の領域分割型境界要素法による解析
    富岡 智, 榎戸 武揚, 深井 一郎
    電気学会 電磁気理論研究会 EMT-87-12 43 - 52 1987年04月 [査読無し][通常論文]

書籍

  • エッセンス電気・電子回路
    佐々木 浩一, 富岡 智 (担当:共著)
    共立出版 2013年11月

講演・口頭発表等

  • 屈折率の三次元分布計測法  [招待講演]
    富岡 智
    先進電磁波イメージング研究会 2019年02月 口頭発表(招待・特別)
  • Phase extraction from interferogram using machine learning  [通常講演]
    Daichi Kando, Satoshi Tomioka
    2019 IS&T International Symposium on Electronic Imaging 2019年01月 口頭発表(一般)
  • Direct Flux Method to Solve Flux Distribution of Two-dimensional Poisson's Equation  [通常講演]
    Arata Hirokami, Satoshi Tomioka
    The 37th JSST Annual International Conference on Simulation Technology 2018年09月 口頭発表(一般)
  • Real-time volumetric image generation with CT image deformation driven by displacement of internal fiducial markers  [通常講演]
    Naoki Miyamoto, Naoki Matsumoto, Ryusuke Suzuki, Seishin Takao, Taeko Matsuura, Takaaki Fujii, Shusuke Hirayama, Satoshi Tomioka, Shinichi Shimizu, Kikuo Umegaki, Hiroki Shirato
    2018 AAPM Annual Meeting 2018年 口頭発表(一般)
  • 重みつきコンピュータトモグラフィーの過渡現象への応用  [通常講演]
    富岡 智
    画像計測研究会2017 2017年09月 口頭発表(一般)
  • 磁場のソレノイダル条件を満たす実座標線形MHDシミュレーション  [通常講演]
    高堂渉, 松本裕, 渡邊清政, 富岡智, 及川俊一
    日本原子力学会年会 2017年09月 口頭発表(一般)
  • 摂動磁場のソレノイダル条件の破綻がLHDのMHDシミュレーションに与える影響  [通常講演]
    高堂渉, 松本裕, 渡邊清政, 富岡智, 及川俊一
    日本物理学会秋期大会 2017年09月 口頭発表(一般)
  • Resonance Mode Analysis of Cavity-ringdown Spectroscopy Including Inhomogeneous Medium Using Modified Fundamental Solution  [通常講演]
    Kazutoshi Matsubara, Satoshi Tomioka, Koichi Sasaki
    プラズマプロセッシング研究会・プラズマ材料科学シンポジウム 2017年01月 ポスター発表
  • キャリア成分を含む干渉縞の位相変調部判別法, 応用物理学会秋期学術講演会  [通常講演]
    貫洞大地, 富岡智
    応用物理学会秋期学術講演会 2016年09月 口頭発表(一般)
  • 体内マーカ3次元軌跡の解析による呼吸位相評価を利用した動体追跡放射線治療の患者位置決め/ゲート照射の効率化  [通常講演]
    宮本直樹, 鈴木隆介, 高尾聖心, 松浦妙子, 松崎有華, 藤井孝明, 富岡智, 清水伸一, 梅垣菊男, 白土博樹
    日本医学物理学会学術大会 2016年09月 口頭発表(一般)
  • 時間的変化を伴う測定対象に対する重みつき計算機トモグラフィー再構成アルゴリズム  [通常講演]
    富岡智, 内藤大基, 西山修輔, 宮本直樹, 梅垣菊男
    日本医学物理学会学術大会 2016年09月 口頭発表(一般)
  • 逐次近似型コンピュータトモグラフィー再構成法における雑音の影響  [通常講演]
    富岡 智
    画像計測研究会2015 2016年01月 口頭発表(一般)
  • ヘリオトロンJのNBI加熱に対する再突入粒子の影響  [通常講演]
    岩淵征, 松本裕, 小林進二, 關良輔, 及川俊一, 富岡智
    プラズマ・核融合学会年会 2015年11月 口頭発表(一般)
  • LHD における三次元中性粒子分布モデルを導入した. NBI 加熱および高速イオン速度分布の解析  [通常講演]
    青木慎一郎, 松本裕, 關良輔, 河村学思, 横山雅之, 神尾修治, 長壁正樹, 及川俊一, 富岡智
    プラズマ・核融合学会年会 2015年11月 口頭発表(一般)
  • 橋本康弘, 富岡智, 西山修輔, 佐々木浩一
    応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集 2015年01月
  • Electron Density Measurement of Argon Containing Plasmas by Saturation Spectroscopy  [通常講演]
    S. Nishiyama, H. Wang, S. Tomioka, K. Sasaki
    67th Annual Gaseous Electronics Conference 2014年11月 口頭発表(一般)
  • Mechanism of efficient generation of cavitation bubbles in a sonoplasma production system assisted by a punching metal plate: effect of power deposition  [通常講演]
    Y. Iwata, S. Nishiyama, S. Tomioka, N. Takada, K. Sasaki
    8th International Conference on Reactive Plasmas 2014年 口頭発表(一般)
  • 佐々木 浩一, 岩田 悠史, 西山 修輔, 富岡 智, 高田 昇治
    超音波エレクトロニクスの基礎と応用に関するシンポジウム講演論文集 2013年11月
  • Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama
    FRINGE 2013 - 7th International Workshop on Advanced Optical Imaging and Metrology 2013年09月 口頭発表(一般)
  • 不完全データによる光音響イメージングにおける音源分布推定の精度評価  [通常講演]
    及川 裕, 富岡 智
    第62回理論応用力学講演会 2013年03月 口頭発表(一般)
  • Effect of mirror size in the measurement of OH density by cavity-ringdown absorption spectroscopy in plasma-enhanced premixed burner flame  [通常講演]
    K. Zaima, S. Tomioka, K. Sasaki
    16th International Symposium on Laser-Aided Plasma Diagnostics 2013年 口頭発表(一般)
  • Mechanism of efficient production of standing sonoplasmas with the help of a punching metal plate  [通常講演]
    K. Sasaki, Y. Iwata, S. Tomioka, S. Nishiyama, N. Takada
    66th Annual Gaseous Electronics Conference 2013年 口頭発表(一般)
  • レーザー照射を利用した材料表面周期パターン創製  [通常講演]
    細川雄亮, 赤松義哲, 石岡準也, 谷津茂男, 渡辺精一, 富岡智
    プラズマ・核融合学会第30回年会 2013年 口頭発表(一般)
  • 拡張ウィンドウを用いたバックグラウンドフリンジを含む干渉縞のキャリア 周波数評価  [通常講演]
    橋本康弘, 富岡智, 西山修輔, 佐々木浩一
    2013年応用物理学会秋季学術講演会 2013年 口頭発表(一般)
  • パンチングメタルを有するソノプラズマ生成装置におけるシャドウグラフイメージング  [通常講演]
    岩田 悠史, 西山 修輔, 富岡 智, 高田 昇治, 佐々木 浩一
    第30回プラズマプロセシング研究会 2013年 口頭発表(一般)
  • 光音響CTにおける音源分布推定の精度評価  [通常講演]
    及川 裕, 富岡 智
    画像計測研究会2013 2013年 口頭発表(一般)
  • 佐々木 浩一, 岩田 悠史, 西山 修輔, 富岡 智, 高田 昇治
    超音波エレクトロニクスの基礎と応用に関するシンポジウム講演論文集 2012年11月
  • Investigation of phase unwrapping process for laser induced plasma interferometry  [通常講演]
    Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama
    7th International Conference on Laser Induced Breakdown Spectroscopy 2012年09月 口頭発表(一般)
  • Phase Unwrapping Algorithm Based on Compensation for 3D Shape Measurement  [通常講演]
    Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama
    The 1st International Laser Display Conference 2012年04月 口頭発表(一般)
  • 位相トモグラフィーによる非接触三次元気体温度分布計測  [通常講演]
    富岡 智
    核融合科学研究所画像計測研究会 2011年09月 口頭発表(一般)
  • 放射化二次元摩耗分布計測におけるソース領域パターンニング法と特異値分解法による空間分解能  [通常講演]
    長沢 裕樹, 西山 修輔, 富岡 智, 佐々木 浩一, 加納 豊広, 金子 卓
    第72回応用物理学会学術講演会 2011年08月 口頭発表(一般)
  • ナノ時空間ダイナミクスのその場観察法による物質変換過程の解明  [通常講演]
    柴山 環樹, 谷津 茂男, 渡辺 精一, 伊藤 芳浩, 富岡 智, 西山 修輔
    日本顕微鏡学会 2011年05月 口頭発表(一般)
  • 単結晶シンチレータ中における三次元発光位置特定法  [通常講演]
    西山 修輔, 富岡 智
    第58回応用物理学関係連合講演会 2011年03月 口頭発表(一般)
  • 外部透明電極と光増幅素子を用いた ナノ秒多チャンネルフレーミングカメラ  [通常講演]
    田坂 陽季, 富岡 智, 佐々木 浩一
    プラズマ・核融合学会第27回年会 2010年11月 口頭発表(一般)
  • Copmarison of OTR from rough screen with He-Ne laser  [通常講演]
    Hayato Aki, Shusuke Nishiyama, Satoshi Tomioka
    Proc. of the 7th Annual Meeting of Particle Accelerator Society of Japan 2010年08月 口頭発表(一般)
  • 仮想特異点を用いた二次元位相アンラッピング  [通常講演]
    Samia Heshmat, Shusuke Nishiyama, Satoshi Tomioka
    第57回 応用物理学関係連合講演会 2010年03月 口頭発表(一般)
  • プラズマ振動周波数測定によるプラズマ密度計測  [通常講演]
    高橋 俊文, 西山 修輔, 富岡 智, 日野 友明
    第26回プラズマ・核融合学会年会 2009年12月 口頭発表(一般)
  • 分光法を用いたアルゴン励起原子温度測定  [通常講演]
    本家 翼, 西山 修輔, 富岡 智, 日野 友明
    第50回真空に関する連合講演会 2009年10月 口頭発表(一般)
  • 分光法を用いたアルゴン励起原子温度測定  [通常講演]
    本家 翼, 西山 修輔, 富岡 智, 日野 友明
    第25回プラズマ・核融合学会年会 2008年12月 口頭発表(一般)
  • 圧縮ベントナイトに対して得られた X線マイクロCT画像の解析  [通常講演]
    富岡 智, 西山 修輔, 小崎 完, 佐藤 正知
    可視化情報学会論文集 2008年10月 口頭発表(一般)
  • 富岡 智, 西山 修輔, 小崎 完, 佐藤 正知
    可視化情報学会誌. Suppl. = Journal of the Visualization Society of Japan 2008年09月
  • 小池 隆太郎, 小崎 完, 高松 英則, 野田 菜摘子, 北市 雅敏, 富岡 智, 西山 修輔, 佐藤 正知
    可視化情報学会誌. Suppl. = Journal of the Visualization Society of Japan 2008年09月
  • 小池 隆太郎, 小崎 完, 高松 英則, 野田 菜摘子, 北市 雅敏, 富岡 智, 西山 修輔, 佐藤 正知
    可視化情報学会誌 2008年
  • 高エネルギー粒子加速器における曲線軌道荷電粒子ビーム航跡場の時間領域境界要素解析  [通常講演]
    藤田 和広, 富岡 智, 川口 秀樹, 日野 友明
    日本原子力学会北海道支部第25回研究発表会 2007年12月 口頭発表(一般)
  • Microstructural image of dry and water-saturated compacted bentonite samples observed with X-ray micro CT  [招待講演]
    Satoshi Tomioka, Tamotsu Kozaki, Hidenori Takamatsu, Natsuko Noda, Shusuke Nisiyama, Naofumi Kozai, Satoru Suzuki, Seichi Sato
    Workshop on long-term performance of smectitic clays embedding canisters with highly radioactive waste 2007年11月 口頭発表(一般)
  • 高松 英則, 野田 菜摘子, 小崎 完, 北市 雅敏, 富岡 智, 佐藤 正知
    粘土科学討論会講演要旨集 2007年09月
  • 粗い金属表面を用いる遷移放射光強度分布の特性  [通常講演]
    宮本 伸之, 北川 広貴, 西山 修輔, 富岡 智, 榎戸 武揚
    日本原子力学会北海道支部第24回研究発表会 2006年12月 口頭発表(一般)
  • 中赤外光計測を目的とした熱吸収型可視位相変調素子の空間分解能  [通常講演]
    富岡 智, 宮本 直樹, 西山 修輔, 榎戸 武揚
    第6回核融合エネルギー連合講演会 2006年06月 口頭発表(一般)
  • 遺伝的アルゴリズムによる汎用非線形最小二乗法  [通常講演]
    富岡 智, 西山 修輔, 榎戸 武揚
    第4回 HSSワークショップ 2006年03月 口頭発表(一般)
  • Infrared phase-shifting interferometer using the nitroanisole as a two-dimensional detector  [通常講演]
    Naoki Miyamoto, Shusuke Nisiyama, Satoshi Tomioka, Takeaki Enoto
    Optomechatronic Sensors and Instrumentation 2005年12月 口頭発表(一般)
  • 赤外画像可視化を利用した屈折率の測定  [通常講演]
    阿部 謙一, 宮本 直樹, 北川 広貴, 西山 修輔, 富岡 智, 榎戸 武揚
    日本原子力学会北海道支部第23回研究発表会 2005年12月 口頭発表(一般)
  • 時間領域境界要素法における行列方程式の反復解法に関する検討  [通常講演]
    藤田和広, 川口秀樹, 富岡智, 榎戸武揚
    平成17年度 電気・情報関連学会北海道支部連合大会 2005年10月 口頭発表(一般)
  • ニトロアニソールを用いた赤外線ホログラフィによる赤外画像の可視化  [通常講演]
    宮本 直樹, 西山 修輔, 富岡 智, 榎戸 武揚
    核融合科学研究所画像計測研究会 2005年08月 口頭発表(一般)
  • 遺伝的アルゴリズムによる重畳波形分離  [通常講演]
    大槻 孝之, 西山 修輔, 富岡 智, 榎戸 武揚
    日本原子力学会北海道支部第22回研究発表会 2004年12月 口頭発表(一般)
  • 新規カルバゾール置換ポリアセチレンの物理特性とデバイス応用  [通常講演]
    牧垣 太郎, 小塚 心尋, 宮坂 淳史, 富岡 智, 榎戸 武揚, 田畑 昌祥
    第53回高分子学会討論会予稿集 2004年09月 口頭発表(一般)
  • 遺伝的アルゴリズムを用いた逆問題解析による相対論的電子ビーム断面形状の推定  [通常講演]
    大槻 孝之, 西山 修輔, 富岡 智, 榎戸 武揚
    日本原子力学会北海道支部第21回研究発表会 2003年12月 口頭発表(一般)
  • 富岡 智, 西山 修輔, 北川 広貴, 榎戸 武揚
    工学・工業教育研究講演会講演論文集 2003年09月
  • 初年度学生に対する簡単な実験を通した知的好奇心の啓発  [通常講演]
    富岡 智, 西山 修輔, 北川 広貴, 榎戸 武揚
    平成15年度 工学・工業教育研究講演会講演論文集 2003年09月 口頭発表(一般)
  • 遺伝的アルゴリズムを用いた相対論的電子ビーム分布の推定  [通常講演]
    大槻孝之, 西山修輔, 富岡智, 榎戸武揚
    核融合科学研究所画像計測研究会 2003年08月 口頭発表(一般)
  • The use of BEM and NN system to estimate density distribution of plasma  [通常講演]
    A. Ota, S. Tomioka, S. Nisiyama, T. Enoto
    International Symposium on Inverse Problems in Engineering Mechanics 2003 2003年02月 口頭発表(一般)
  • 光増幅素子の光電面放出電子のエネルギー特性の評価  [通常講演]
    岡田直之, 西山修輔, 富岡智, 榎戸武揚
    日本原子力学会北海道支部第20回研究発表会 2002年12月 口頭発表(一般)
  • An improvement method of the simultaneity of images on ultra high speed x-ray framing camera with the gated microchannel plate detector  [通常講演]
    Yoshihiro Ito, Yasuto Katoh, Makoto Kagata, Shusuke Nisiyama, Satoshi Tomioka, Takeaki Enoto
    The International Society for Optical Engineering / 25th International Congress on High-Speed Photography and Photonics 2002年 口頭発表(一般)
  • 赤外線二次元検出用液晶の温度・電界依存性の研究  [通常講演]
    宮本 直樹, 西山 修輔, 富岡 智, 榎戸 武揚
    日本原子力学会北海道支部第19回研究発表会 2001年12月 口頭発表(一般)
  • 赤外線実時間二段ホログラフィ干渉法の向上に関する研究  [通常講演]
    野村 啓一, 宮本 直樹, 逵 由典, 富岡 智, 榎戸 武揚
    電気関係学会北海道支部連合大会 2001年10月 口頭発表(一般)
  • Scattered field FD-TD analysis for wake-fields computation  [通常講演]
    S. Nisiyama, S.Tomioka, T. Enoto
    Proc. of 10th Int. Symp. on Simulation and Design of Applied Electromagnetics and Mechanics 2001年 口頭発表(一般)
  • 電子ビームによる放射電磁界への近傍金属の影響  [通常講演]
    杉山 耕太郎, 西山 修輔, 富岡 智, 榎戸 武揚
    日本原子力学会北海道支部第18回研究発表会 2000年12月 口頭発表(一般)
  • ニトロベンゼンを遠赤外線二次元検出材料として用いた二段ホログラフィー干渉法  [通常講演]
    原山 武志, 榎戸 武揚, 富岡 智
    日本原子力学会北海道支部 第17回研究発表会 1999年12月 口頭発表(一般)
  • 分布ソースを有する3次元ポアッソン方程式の多重相反境界要素法解析  [通常講演]
    四方純, 板垣正文, 富岡智, 榎戸武揚
    日本原子力学会北海道支部 第16回研究発表会 1998年12月 口頭発表(一般)
  • 超高速度フレームカメラのMTF特性の解析  [通常講演]
    加藤 靖人, 風間 信幸, 今井 応介, 富岡 智, 榎戸 武揚
    高速度撮影とフォトニクスに関する総合シンポジウム1997 1997年12月 口頭発表(一般)
  • FD-TD法による超高速駒取りカメラのシャッタリング特性の解析  [通常講演]
    加賀田 誠, 富岡 智, 榎戸 武揚
    高速度撮影とフォトニクスに関する総合シンポジウム1995 1995年12月 口頭発表(一般)
  • 遠赤外領域ホログラフィ干渉法を目的としたHgCdTe赤外線検出器の空間解像度の改善  [通常講演]
    竹内 久美子, 山下 靖二, 富岡 智, 榎戸 武揚
    プラズマ核融合学会第11回年会 1994年03月 口頭発表(一般)
  • FD-TD法を用いる電子線加速器電子ビームの作る電磁界解析  [通常講演]
    伊藤裕康, 西山修輔, 富岡智, 榎戸武揚
    日本原子力学会北海道支部第11回研究発表会 1993年12月 口頭発表(一般)
  • CO_2レーザ干渉体系を用いるHgCdTe赤外線検出器のMTF特性の測定度の改善  [通常講演]
    竹内 久美子, 富岡 智, 榎戸 武揚
    電気関係学会北海道支部連合大会 1993年10月 口頭発表(一般)
  • FD-TD法による超高速カメラシャッタリング特性の解析  [通常講演]
    榎戸武揚, 富岡智, 加賀田誠, 町谷顕
    プラズマ・核融合学会第9回秋季講演会 1992年10月 口頭発表(一般)
  • 超高速度撮影装置の開発と核融合プラズマ計測への応用  [通常講演]
    榎戸 武揚, 木村 雅紀, 富岡 智, 春山 和郎, 深井 一郎, 遠藤 彰, 吉田 貴彦
    北海道核融合連絡者会議第1回研究報告書 1988年 口頭発表(一般)
  • 分布を持つプラズマを含む開放型共振器に対する境界要素法適用の試み  [通常講演]
    富岡 智, 榎戸 武揚, 深井 一郎
    日本原子力学会北海道支部第5回研究発表会 1987年12月 口頭発表(一般)
  • 境界要素法による開放型共振器の領域分割問題の解析  [通常講演]
    富岡 智, 榎戸 武揚, 深井 一郎
    日本原子力学会北海道支部第4回研究発表会 1986年12月 口頭発表(一般)
  • 境界要素法による領域分割問題の解析  [通常講演]
    富岡 智, 深井 一郎, 榎戸 武揚
    電気関係学会北海道支部連合大会 1986年10月 口頭発表(一般)

その他活動・業績

特許

  • 加納 豊広, 金子 卓, 萩原 康正, 宮田 学, 富岡 智, 西山 修輔  株式会社デンソー, 国立大学法人北海道大学  201203099047387679
  • 金子 卓, 加納 豊広, 宮田 学, 萩原 康正, 富岡 智, 西山 修輔  株式会社デンソー, 国立大学法人北海道大学  201203030562144517

受賞

  • 2007年 プラズマ・核融合学会賞 貢献賞
  • 2007年 JSPF Award for Notable Contribution to our communitiy

共同研究・競争的資金等の研究課題

  • 文部科学省:科学研究費補助金(基盤研究(C))
    研究期間 : 2015年 -2017年 
    代表者 : 富岡 智
  • 文部科学省:科学研究費補助金(基盤研究(C))
    研究期間 : 2012年 -2014年 
    代表者 : 富岡 智, 西山 修輔
     
    本研究で検討している気体温度の三次元計測では、複数の方向から測定した干渉画像を計算機にて三次元分布を再構成する。そのためには投影方向が可変の干渉計のハードウェアおよび、それを処理するためのソフトウェア群が必要であり、本年度はこれら両面の改善を行った。ハードウェアについては、計測時間の短縮を図った。いままでは、一連の計測データを得るために数十分の計測時間を要していた。これは、干渉画像が振動に弱いため、投影方向を変えるたびに発生する干渉計を構成しているミラーの振動の計測への影響を抑えるために、振動が収まった後に計測していためである。この計測時間を短縮するために、幾つかの検討を行った結果、投影方向を連続的に変えながら、干渉画像を取り込む方法に変更し、振動が計測に与える影響を取り除くために、画像の撮影時間をサブミリ秒に短くした。以上により、計測時間は数十秒と短縮することができた。ソフトウェアは、干渉画像から位相画像を求めるための処理、複数の位相画像から屈折率の三次元分布再構成処理に大別される。位相画像を求めるには、雑音除去、位相情報を含むキャリア周辺信号の抽出、位相連結の三つの手順が必要である。本年度は、位相連結に特化した雑音除去方法の開発、ロバストなキャリア周辺信号の抽出方法の開発、位相アンラッピング手法の高速化を行った。三次元分布再構成については、高精度化のための体系変更のシミュレーションを行った。可変干渉計から得られる計測データは、通常のコンピュータトモグラフィーと異なり、全ての投影方向からのデータを得ることができず、一部の投影データが欠落してしまい、三次元再構成の精度が悪くなることが解っている。これを改善するために、欠落している投影方向の範囲に、方向が固定の投影データを一つだけ取り込むことにより精度の向上ができないかを検討し、この方法が有効であることが示された。
  • 文部科学省:科学研究費補助金(基盤研究(C))
    研究期間 : 2009年 -2011年 
    代表者 : 富岡 智, 西山 修輔, 加美山 隆, 坂下 弘人
     
    気体の温度分布や液体の濃度分布を測定する場合、熱電対等のセンサーを挿入すると測定対象の状態が変わってしまうため、正しい測定ができない。本研究では、光をプローブとした干渉法による位相計測とコンピュータトモグラフィーの組み合わせによる、位相トモグラフィーを用いて三次元かつ非接触な屈折率分布計測を検討した。これにより発熱体周辺の気体の温度を求め、理論値と比べ定性的に妥当な結果が得られた。
  • 文部科学省:科学研究費補助金(基盤研究(C))
    研究期間 : 2005年 -2007年 
    代表者 : 富岡 智, 榎戸 武揚, 西山 修輔
     
    分子の結合状態は原子核の周辺の電子の状態で決まり、この状態はシュレディンガー方程式と呼ばれる未知固有値を含む偏微分方程式によって表わされ、一般に、摂動を用いた近似的な数値解法が用いられる。本研究では、シュレディンガー方程式を積分表現し、電子の分布を表す波動関数を固有関数展開(既知の固有関数が任意の重みの重ね合わせ)を用い、その展開係数(重み)をシュレディンガー方程式が満足するように決定する。さらにこの固有関数群にある条件を満足するように選ぶことにより、領域積分を級数和に変換する手法を検討した。この方法では、通常の偏微分方程式の解法に必要な格子が不要であること、さらに領域積分も不要であることから、いずれの計算過程にも離散化による近似を含まないのが特徴である。展開係数の決定には、研究の前半では、生物の進化を模擬した遺伝的アルゴリズムを用いた。遺伝的アルゴリズムは、解探索アルゴリズムであり、展開係数を染色体とみなし、染色体の集合の中で方程式を満足しやすい個体同士により新たな子孫を生成し、最終的に方程式をほぼ満足する個体(展開係数)を決定する。これらの組合せにより、水素原子のような球対称のポテンシャルにおいて解を決定できることが示せた。また、電界中の水素原子のような非球対称問題についても、固有関数の積の領域積分が近似のない級数和へ変換可能なことを示した。さらに、遺伝的アルゴリズムを用いなくても、連立一次方程式として方程式を解く方法も判り、これにより高速な計算が可能となった。しかし、複数電子の問題までは残念ながら解決には至っていない。一方で、遺伝的アルゴリズムも染色体の定義域を自動的に変更できるアルゴリズムを開発した。これは、本研究での目的である非線形方程式の解法に限らず、不連続関数へのフィッティング問題でさえ、有効であることが判った。
  • 文部科学省:科学研究費補助金(奨励研究(A))
    研究期間 : 2000年 -2001年 
    代表者 : 富岡 智
     
    本研究の目的は、電子ビームから放出されるパルス状電磁界の時間プロファイル測定である。このパルスは2.85GHzの加速周波数とその高調波より構成されており、それらの複素スペクトルを測定すれば、元の時間プロファイルを決定できる。複素スペクトルとは各成分の振幅の絶対値と位相を表している。通常の計測法では、各成分の絶対値のみしか分からないが、二つの周波数成分を同時に計測し、さらに、この一方に移相器(遅波回路)を挿入することにより、二つの周波数成分間の位相差が計測できる。本研究では、この測定に、共振周波数を自由に選ぶことが出来、さらに複数の周波数成分を同時にフィルタリング(選択)することも出来る開放型共振器を採用した。開放型共振器には、電磁波の入射ポートを設け、大きな出力を得るために、出力検出用の四本のモノポールアンテナを直接共振器に挿入した。挿入した四本のアンテナは、各々、基本波(2.85GHz)、第二、第三、第四高調波を主として検出する位置に設置した。このうち、第四高調波は出力が弱く複素スペクトルの計測は不可能であった。これらのアンテナの内の、基本波の出力に移相器を挿入し、他の高調波成分の一つの出力と合成し、その位相遅れを計測した。また、各々の成分単体の出力を計測した。なお、入力ポートから各アンテナまでの位相遅れについても、同様の方法で計測し、各周波数成分は入力ポートにおける複素振幅に換算できる。以上により、基本波から第三高調波までではあるが、複素スペクトルを求め、加速器の時間プロファイルを求めることができた。この結果は、他の計測法との定量的な比較は行ってはいないが、定性的には妥当な結果を示していた。本来は、加速器からの放射電磁界は第五高調波程度まで延びているため充分な精度の計測はできなかったが、本研究で提案した複素スペクトルの計測法は、実現可能な手法であることが示された。
  • Measurement of infrared light
    研究期間 : 1999年
  • Inverse problem using genetic algorithm
    研究期間 : 1999年
  • 文部科学省:科学研究費補助金(奨励研究(A))
    研究期間 : 1997年 -1998年 
    代表者 : 富岡 智
     
    今年度の研究成果を、信号取得に関するハードウェアと、信号処理に関する分散処理を行う逆問題解析ソフトウェアに分けて、以下に記す。・信号取得系(ハードウェア)昨年度評価を行ったスロットアンテナの他、今年度は、開放型共振器の試作・評価を線形加速器を用いて行った。開放型共振器の特徴として、鏡面間隔を実験をしながら変更することができ、複数の周波数を選択的に検出すること挙げられる。実験結果から昨年度行った解析と定性的に一致することが確認でき、さらに、その出力は十分であることが分かった。ただし、装置がスロットアンテナに比べて、若干大規模になるため、現在のところ、スロットアンテナとバンドパスフィルタを組み合わせた体系の方が有望である。また、バンドパスフィルタとの組合せにより、複数の周波数成分の位相差の検出の可能性を見出した。このことは、開放型共振器が断面内分布のみならず、軸方向分布のプロファイルモニターへの応用の可能性を示している。・信号処理系(ソフトウェア)昨年度、完成させた遺伝的アルゴリズムに加え、新たにカルマンフィルタ、疑似データ生成系を新たに作成し、総合評価を行った。カルマンフィルタによる測定誤差の軽減により、遺伝的アルゴリズムの推定の効率を高めることが確認できた。一方、ほぼ正しい推定はできているが稀に特異な解に収束する場合があらわれた。本システムは、推定すべきパラメータ数が測定データ数より多いため、評価関数により最適なものを選んでいるが、その評価関数の選び方にさらなる工夫が必要であることを示している。残念ながら、これについては今後の検討課題である。また、遺伝的アルゴリズムのさらに内側では、境界要素法を用いているが、この境界要素法の高精度化、開放領域問題への新たなアプローチを開発し、その成果を公表した。
  • 文部科学省:科学研究費補助金(奨励研究(A))
    研究期間 : 1992年 -1992年 
    代表者 : 富岡 智
  • Relativistic electron beam measurement
    研究期間 : 1992年
  • Plasma diagnostics using electromagnetic wave
    研究期間 : 1990年

教育活動情報

主要な担当授業

  • 医理工画像工学
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 医理工学院
    キーワード : スペクトル、フーリエ変換、畳み込み積分、レスポンス関数、画像情報処理、雑音除去フィルター、コンピュータトモグラフィー(CT)、核磁気共鳴画像法(MRI)、超音波計測法 spectrum, Fourier transform, convolution integral, response function, image processing, noise reduction filter, computer tomography, magnetic resonance imaging, ultrasonography
  • 画像工学特論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 工学院
    キーワード : スペクトル、フーリエ変換、畳み込み積分、レスポンス関数、画像情報処理、雑音除去フィルター、コンピュータトモグラフィー(CT)、核磁気共鳴画像法(MRI)、超音波計測法
  • 画像工学特論
    開講年度 : 2021年
    課程区分 : 博士後期課程
    開講学部 : 工学院
    キーワード : スペクトル、フーリエ変換、畳み込み積分、レスポンス関数、画像情報処理、雑音除去フィルター、コンピュータトモグラフィー(CT)、核磁気共鳴画像法(MRI)、超音波計測法
  • コンピュータ演習
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : コンピュータ、プログラム、数値計算
  • 電気・電子回路
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 線形受動回路,複素インピーダンス,周波数特性,過渡現象,トランジスタ回路,ダイオード回路,オペアンプ回路
  • 情報学 Ⅰ
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 情報活用,情報社会,情報科学,プログラミング,データサイエンス
  • 制御・電気工学演習
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 制御工学、電気工学、電磁気学
  • 一般教育演習(フレッシュマンセミナー)
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 量子ビーム、プラズマ、触媒、ナノ材料

大学運営

委員歴

  • 2001年 - 現在   日本計算数理工学会   委員   日本計算数理工学会
  • 1999年 - 現在   プラズマ・核融合学会   電子化小委員会委員   プラズマ・核融合学会


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