博士(工学), 千葉大学

Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Electrical power engineering

Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Electronic devices and equipment

01 Sep. 2014
内閣府, 総合科学技術・イノベーション会議事務局 政策統括官（科学技術・イノベーション担当）付, 上席科学技術政策フェロー

01 Mar. 2013 - 31 Aug. 2014
内閣府, 総合科学技術・イノベーション会議事務局 政策統括官（科学技術・イノベーション担当）付, 上席政策調査員

Mar. 2000
Chiba University, Graduate School, Division of National Science and Technology (except Gakushuin University, Konan University), 人工システム科学専攻

Mar. 1995
Chiba University, Faculty of Engineering, 電気電子工学科

01 Apr. 1988 - 31 Mar. 1991
千葉県立千葉東高等学校

Apr. 2022 - Mar. 2024
エレクトロニクスシミュレーション研究専門委員会幹事, 電子情報通信学会, Society

01 Apr. 2013 - 31 Mar. 2014
基礎・材料・共通部門誌論文委員会Ａ１主査, 電気学会, Society

May 2011 - Apr. 2013
電磁界理論研究専門委員会幹事, 電子情報通信学会, Society

01 Apr. 2012 - 31 Mar. 2013
基礎・材料・共通部門誌論文委員会Ａ１副主査, 電気学会, Society

Apr. 2009 - Mar. 2012
基礎・材料・共通部門誌論文委員会Ａ１幹事, 電気学会, Society

May 2003 - May 2009
電磁界理論研究専門委員会委員, 電子情報通信学会, Society

01 May 2009
英文誌C編集委員会, 電子情報通信学会, Society

Apr. 2006 - Mar. 2008
基礎・材料・共通部門調査運営委員会幹事, 電気学会, Society

Apr. 2005 - Mar. 2008
電磁界理論技術委員会幹事, 電気学会, Society

Apr. 2002 - Mar. 2005
電磁界理論技術委員会幹事補佐, 電気学会, Society

Apr. 2024
日本大気電気学会
入江俊行, 安藤芳晃「VLF 帯伝搬の時間変動を用いた下部電離圏電子密度推定の数値的検証」
日本大気電気学会 学生発表表彰, 入江俊行;安藤芳晃

Mar. 2022
日本大気電気学会
木村、安藤、服部、早川「WLP-FDTD法を用いた地殻変動に伴うULF帯電磁放射の波源電流強度推定の高精度化」
日本大気電気学会 学生発表表彰, 木村亮太
Japan society

Jan. 2020
日本大気電気学会
3次元球座標系FDTD法によるVLF/LF帯大地-電離圏導波管伝搬シミュレーション法の開発
日本大気電気学会 学生発表表彰, 関根健太;安藤芳晃

Mar. 2019
電子情報通信学会
電子情報通信学会エレクトロニクスソサイエティ活動功労表彰
Others

Mar. 2014
電子情報通信学会エレクトロニクスソサイエティ活動功労表彰

Aug. 2007
電気学会
電気学会優秀論文発表賞
Japan society

Mar. 2004
電気学会
電気学会優秀論文発表賞
Japan society

A Numerical Consideration on the Correlation Between Magnitude of Earthquakes and Current Intensity Causing ULF Electromagnetic Wave Emission
Ryota Kimura; Yoshiaki Ando; Leo Kukiyama; Tomoya Masuzawa; Katsumi Hattori; Masashi Hayakawa
Corresponding, Radio Science, American Geophysical Union (AGU), 59, 7, 20 Jul. 2024, Peer-reviwed, Abstract

Numerous studies have reported anomalous ultralow frequency (ULF) electromagnetic fields preceding earthquakes. In this paper, we estimate the current intensity responsible for generating the earthquake‐related ULF fields under the assumption that the origin is a current flowing at the hypocenter and that it has the same frequency dependence for all cases. To estimate current intensity, we perform ULF electromagnetic field simulations with an absorbing boundary condition developed in this study, taking into account the conductivity distribution of the Earth's crust. We analyze 11 earthquakes, including those that occurred in Loma Prieta, Spitak, Guam, Biak, Kagoshima, Iwateken Nairiku Hokubu, Izu swarm, Jammu and Kashmir, Alum Rock, Wenchuan, and L’Aquila. Our results show that, for nine out of the 11 events, there is a positive correlation between current intensity and earthquake magnitude, suggesting that the measured ULF fields originate from seismic activity and supporting our assumptions.
Scientific journal, English

An identification of ambient electron density profile in the lower ionosphere by using a temporal variation of VLF earth-ionosphere waveguide propagation
Toshiyuki Irie; Yoshiaki Ando
Last, 電子情報通信学会論文誌C, J107-C, 5, 217-224, May 2024, Peer-reviwed
Scientific journal, Japanese

WLP-FDTD法を用いた地殻変動に伴うULF帯電磁放射の波源電流強度推定の高精度化
木村亮太; 安藤芳晃; 服部克巳; 早川正士
Corresponding, Journal of Atmospheric Electricity, 41, 2, 52-57, Oct. 2022, Peer-reviwed
Scientific journal, Japanese

Detection of Polar Mesospheric Clouds Utilizing Himawari-8/AHI Full-Disk Images
T. T. Tsuda; Y. Hozumi; K. Kawaura; K. Tatsuzawa; Y. Ando; K. Hosokawa; H. Suzuki; K. T. Murata; T. Nakamura; J. Yue; K. Nielsen
Earth and Space Science, 9, 1, e2021EA002076, Dec. 2021, Peer-reviwed
Scientific journal, English

Horizontal Movement of Polar Mesospheric Clouds Observed From the Himawari-8 Geostationary Meteorological Satellite
Yuta Hozumi; Takuo T. Tsuda; Keisuke Hosokawa; Yoshiaki Ando; Hidehiko Suzuki; Takeshi Murata; Takuji Nakamura
Journal of Geophysical Research, Atmospheres, 126, 19, e2021JD035081, 16 Oct. 2021, Peer-reviwed
Scientific journal, English

Numerical simulation of ULF/SLF/ELF electromagnetic waves propagating in the lithosphere by using WLP-FDTD method
Y. Ando
2019 URSI-Japan Radio Science Meeting, E-2-3, Sep. 2019, Peer-reviwed, Invited
International conference proceedings, English

大学において授業外学習を促すeラーニング教材に関する一検討
安藤
電気学会論文誌Ａ（基礎・材料・共通部門誌）, 電気学会, 138, 4, 147-154, 01 Apr. 2018, Peer-reviwed
Scientific journal, Japanese

An Approximate PML Applied to Cylindrical and Spherical Coordinate Sectors
Y. Ando
IEEE Microw. Wireless Compon. Lett., 28, 9, 741-743, 2018, Peer-reviwed
Scientific journal, English

注入同期のロックレンジを最大化する入力信号波形 -CMOSリングオシレータを例として-
矢部, 西川; 中田; 守川; 関屋; 安藤, 田中
電子情報通信学会論文誌C, 電子情報通信学会, J99-C, 6, 298-313, Jun. 2016, Peer-reviwed
Scientific journal, Japanese

VLF帯大地-電離圏導波管伝搬を用いた電子密度同定問題における適切なパラメタ選択
安藤; 伊藤
電気学会A部門誌, 電気学会, 136, 5, 304-309, 01 May 2016, Peer-reviwed, We consider an problem identifying electron density profile in the lower ionosphere by observing electric fields at the Earths surface in very-low-frequency (VLF) band. The identification problem is one of nonlinear inverse problems, and we solve the problem numerically by using the genetic algorithm in this study. The focus of this study is on appropriate parameters to solve the identification problem by using the VLF (22.2 kHz) wave propagating in the Earth-ionosphere waveguide. Numerical results show that the range of the electron density which can be identified is from 107-108 m-3, appropriate discretization of the solution space along the altitude is 10 km, and a sufficient number of observation points are necessary to mitigate the effect of noise.
Scientific journal, Japanese

A subgridding technique for the CIP method
Yoshiaki Ando; Takashi Hirota
IEEE International Symposium on Electromagnetic Compatibility, Institute of Electrical and Electronics Engineers Inc., 2014-, 801-804, 23 Dec. 2014, In this study, we propose a subgridding technique in the constrained interpolation profile (CIP) method in order to simulate electromagnetic fields in the presence of objects with fine structures. The subgridding technique consists of spatial and temporal interpolations at the interface between main coarse grids and local fine grids. In the present study, we consider a two-dimensional problem with TMz polarization. In order to examine the validation of the proposed method, spatial and temporal interpolation schemes are implemented separately. The numerical results show that both the interpolation schemes operate successfully, and the relative errors are extremely small in wide frequency band.
International conference proceedings, English

CIP Basis Set Method for Electromagnetic Simulation
Yoshiaki Ando; Yusuke Takahashi
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E97C, 1, 26-32, Jan. 2014, Peer-reviwed, This paper presents an application of the constained interpolation profile basis set (CIP-BS) method to electromagnetic fields analyses. Electromagnetic fields can be expanded in terms of multi-dimensional CIP basis functions, and the Galerkin method can then be applied to obtain a system of linear equations. In the present study, we focus on a two-dimensional problem with TMz polarization. In order to examine the precision of the CIP-BS method, TE202 resonant mode in a rectangular cavity is analyzed. The numerical results show that CIP-BS method has better performance than the finite-difference time-domain (FDTD) method when the time step is small. Then an absorbing boundary condition based on the perfectly matched layer (PML) is formulated, and the absorption performance is demonstrated. Finally, the propagation in an inhomogeneous medium is computed by using the proposed method, and it is observed that in the CIP-BS method, smooth variation of material constants is effectively formulated without additional computational costs, and that accurate results are obtained in comparison with the FDTD method even if the permittivity is high.
Scientific journal, English

A Subgridding Technique for the CIP Method
Yoshiaki Ando; Takashi Hirota
2014 INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY, TOKYO (EMC'14/TOKYO), IEEE, 801-804, 2014, Peer-reviwed, In this study, we propose a subgridding technique in the constrained interpolation profile (CIP) method in order to simulate electromagnetic fields in the presence of objects with fine structures. The subgridding technique consists of spatial and temporal interpolations at the interface between main coarse grids and local fine grids. In the present study, we consider a two-dimensional problem with TMz polarization. In order to examine the validation of the proposed method, spatial and temporal interpolation schemes are implemented separately. The numerical results show that both the interpolation schemes operate successfully, and the relative errors are extremely small in wide frequency band.
International conference proceedings, English

Simplified analysis techniques for VLF wave propagation in the earth-ionosphere waveguide
Hitoshi Itoh; Yoshiaki Ando; Masashi Hayakawa
ELECTRICAL ENGINEERING IN JAPAN, WILEY-BLACKWELL, 183, 1, 25-31, Apr. 2013, Peer-reviwed, VLF (very low frequency; 3 to 30 kHz) wave propagation in the earthionosphere waveguide can be simply analyzed by the method developed in this paper. The finite-difference time-domain (FDTD) method is used with a conductivity tensor to model the ionosphere, and the applicability is limited to monotonic cases. The proposed method is compared with the wideband method, and it is concluded that the newly developed method can be used as a VLF wave simulator without errors. Conformal FDTD is also introduced to allow for the curvature of the earth's surface, and we have clarified the difference between two-dimensional modeling in Cartesian coordinates and cylindrical coordinates. (c) 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 183(1): 2531, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22302
Scientific journal, English

A Multi-dimensional CIP-BS Method for Electromagnetic Simulation
Y. Ando; Y. Takahashi
PIERS2012, 2012, Mar. 2012
International conference proceedings, English

A Total-Field/Scattered-Field Boundary for the Multi-Dimensional CIP Method
Yoshiaki Ando; Satoi Murakoshi
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E95C, 1, 115-121, Jan. 2012, Peer-reviwed, A total-field/scattered-field (TF/SF) boundary for the constrained interpolation profile (CIP) method is proposed for multidimensional electromagnetic problems. Incident fields are added to or subtracted from update equations in order to satisfy advection equations into which Maxwell's equations are reduced by means of the directional splitting. Modified incident fields are introduced to take into account electromagnetic fields after advection. The developed TF/SF boundary is examined numerically, and the results show that it operates with good performance. Finally, we apply the proposed TF/SF boundary to a scattering problem, and it can be solved successfully.
Scientific journal, English

VLF帯大地-電離層導波管伝搬の簡易FDTD解析法
伊藤; 安藤; 早川
電気学会Ａ部門誌, 131, 9, 744-749, Sep. 2011, Peer-reviwed
Scientific journal, Japanese

Simplified analysis techniques for VLF wave propagation in the Earth-Ionosphere waveguide
Hitoshi Itoh; Yoshiaki Ando; Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 131, 9, 744-749, 2011, Peer-reviwed, VLF (Very low frequency
3-30 kHz) wave propagation in the Earth-Ionosphere waveguide can be simply analyzed by the method developed in this paper. The finite-difference time-domain (FDTD) method is used with a conductivity tensor to model the Ionosphere, and the applicability is limited in monotonic cases. The proposed method is compared with the wideband one, and it is concluded that the developed method can be used as the VLF wave simulator without errors. Moreover, the conformal FDTD is introduced to consider the curvature of the Earth's surface, and we have clarified the difference between the two-dimensional modeling in the Cartesian coordinates and the cylindrical ones. © 2011 The Institute of Electrical Engineers of Japan.
Scientific journal, Japanese

CIP-BS Method for Solving Maxwell's Equations
Y. Ando; A. Noba; S. Murakoshi
AP-RASC'10, BEFKb, Sep. 2010
International conference proceedings, English

CIP-BS Method for Solving Maxwell's Equations
Y. Ando
URSI EMTS, P1, Aug. 2010
International conference proceedings, English

CIP-BS method for solving maxwell's equations
Yoshiaki Ando; Akira Noba; Satoi Murakoshi
Symposium Digest - 20th URSI International Symposium on Electromagnetic Theory, EMTS 2010, 4P3, 111-113, 2010, The CIP-basis set (CIP-BS) method for electromagnetic fields is developed in this paper. Electromagnetic fields are expanded into linear combinations of basis functions with arbitrarily higher order polynomials and linear equations are obtained by using the Galerkin method. Various schemes of CIPBS method are proposed, and the numerical results show that all of them work successfully. © 2010 IEEE.
International conference proceedings, English

Total-field/Scattered-field Boundary for Multi-dimensional CIP Method
Yoshiaki Ando; Satoi Murakoshi; Masashi Hayakawa
PIERS2009, 4A5, Aug. 2009
International conference proceedings, English

Reconstruction of the global lightning distribution from ELF electromagnetic background signals
A. V. Shvets; M. Hayakawa; M. Sekiguchi; Y. Ando
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 71, 12, 1405-1412, Aug. 2009, Peer-reviwed, The global lightning distribution has been obtained for the first time as the result of an inverse problem for the natural extremely low-frequency (ELF) electromagnetic background signals measured simultaneously at three stations: Lekhta (Karelia, Russia), Moshiri (Hokkaido, Japan), and West Greenwich (Rhode Island, USA). We employed a two-step technique consisting of: (1) inversion of ELF field spectra to a source distance distribution (distance profile) for each station of the network and (2) treating the obtained distance profiles as projections in the tomographic method. The structure of the source distance profiles reconstructed from experimental field spectra, varies during a day in a manner specific for each station, which can be explained generally by the temporal distribution of the sources in the tropical continental areas, so-called world thunderstorm centres (WTCs). The comparison of the obtained source distributions with the satellite data on lightning collected by Optical Transient Detector (OTD) and Lightning Imaging Sensor (LIS) shows satisfactory agreement, which proves that our newly developed inversion technique is a suitable method for mapping global lightning. (C) 2009 Published by Elsevier Ltd.
Scientific journal, English

A Nearly Perfect Total-Field/Scattered-Field Boundary for the One-Dimensional CIP Method
Yoshiaki Ando; Hiroyuki Saito; Masashi Hayakawa
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E91C, 10, 1677-1683, Oct. 2008, Peer-reviwed, A total-field/scattered-field (TF/SF) boundary which is commonly used in the finite-difference time-domain (FDTD) method to illuminate scatterers by plane wades, is developed for use in the constrained interpolation profile (CIP) method. By taking the numerical dispersion into account. the nearly perfect TF/SF boundary can be achieved, which allows us to calculate incident fields containing high frequency components without fictitious scattered fields. First of all. we formulate the TF/SF boundary in the CIP scheme. The numerical dispersion relation is then reviewed. Finally the numerical dispersion is implemented in the TF/SF boundary to estimate deformed incident fields. The performance of the nearly perfect TF/SF boundary is examined by measuring leaked fields in the SF region. and the proposed method drastically diminish the leakage compared with the simple TF/SF boundary.
Scientific journal, English

Characteristics of Japanese winter sprites and their parent lightning as estimated by VHF lightning and ELF transients
Yu Matsudo; Tomoyuki Suzuki; Masashi Hayakawa; Kozo Yamashita; Yoshiaki Ando; Koichiro Michimoto; V. Korepanov
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, PERGAMON-ELSEVIER SCIENCE LTD, 69, 12, 1431-1446, Aug. 2007, Peer-reviwed, Sprites are newly discovered optical emissions in the mesosphere over large thunderstorms. This paper is the observational summary of winter sprites in the Hokuriku area of Japan and their parent lightning in the winter of 2004/ 2005 by using the coordinated optical and electromagnetic (VHF and ELF) measurements in Japan. As the results of optical observations at two stations, we have found that this campaign has yielded a variety of sprite shapes; V-angle shaped structures have been often observed (25%) in addition to columnar structures familiar for us. All of the sprite events are found to be associated with +CG lightning, as seen from the macroscopic information by ELF data at Moshiri. However. examining the microscopic properties of parent lightning as seen from the VHF SAFIR lightning detection network, has suggested very complicated characteristics of parent lightning discharges inducing sprites, as compared with the ELF data. One half of the sprite events are also found to be associated with +CG by the SAFIR observation, but another half has yielded rather new results as compared with earlier results. Four events are definitely associated with -CG and the remaining three events, inter-cloud flashes. The overall picture for Japanese winter sprites and their parent lightning discharges. is significantly different from that for the summer-time, continental sprites. This is indicative of complexity of winter lightning in the Hokuriku area of Japan and this would provide new information on the sprite generation mechanism. (C) 2007 Elsevier Ltd. All rights reserved.
Scientific journal, English

Use of generalized cross validation for identification of global lightning distribution by using Schumann resonances
Yoshiaki Ando; Masashi Hayakawa
RADIO SCIENCE, AMER GEOPHYSICAL UNION, 42, 2, RS2S16, Jan. 2007, Peer-reviwed, [1] In this paper, generalized cross validation is implemented to solve an inverse problem to identify global lightning distribution from measured Schumann resonance. The inverse problem to identify the lightning distribution as a function of the distance from the observer is formulated in terms of Schumann resonance spectra calculated by the finite difference method. Tikhonov's regularization is introduced for proper inversion, and the optimal parameter for the regularization is evaluated by using the generalized cross validation as an objective estimation. We compared the results obtained in the present paper with the data collected by the Lightning Image Sensor during December 1999, and this comparison shows a better agreement than the previous results.
Scientific journal, English

CIP method for electromagnetic scattering problems
Y. Ando; M. Hayakawa
KJJC2006 Proceedings, 401-404, Sep. 2006, Peer-reviwed
International conference proceedings, English

Total-Field/Scattered-Field boundary condition for CIP method
Y. Ando; M. Hayakawa
PIERS2006-Tokyo Abstracts, 429, Aug. 2006, Peer-reviwed
International conference proceedings, English

Implementation of the perfect matched layer to the CIP method
Yoshiaki Ando; Masashi Hayakawa
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E89C, 5, 645-648, May 2006, Peer-reviwed, The perfect matched layer (PML) is formulated for the use in the constrained interpolation profile (CIP) method. Numerical results are presented to examine the performance of the proposed formulation of the PML in the case of two-dimensional TM wave. The results show that the proposed methods suppress the reflection effectively in comparison with the natural absorbing boundary condition of the CIP method. We have two methods to formulate the PML, and it is shown that the both methods have equal characteristics.
Scientific journal, English

Model modifications in Schumann resonance intensity caused by a localized ionosphere disturbance over the earthquake epicenter
A. P. Nickolaenko; M. Hayakawa; M. Sekiguchi; Y. Ando; K. Ohta
Ann. Geophys., 24, 567-575, Mar. 2006, Peer-reviwed
Scientific journal, English

Implementation of the PML in the CIP Method
Y. Ando; M. Hayakawa
-, Mar. 2006
International conference proceedings, English

Recent studies on Schumann resonance
Yoshiaki Ando; Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 126, 1, 28-30, 2006, Peer-reviwed, Recent studies on Schumann resonance, natural electromagnetic resonance in the Earth-ionosphere shell-cavity, axe summarized briefly.
Scientific journal, English

Finite difference analyses of Schumann resonance and reconstruction of lightning distribution
Y Ando; M Hayakawa; AV Shvets; AP Nickolaenko
RADIO SCIENCE, AMER GEOPHYSICAL UNION, 40, 2, Mar. 2005, Peer-reviwed, This paper deals with the computation of extremely low frequency propagation associated with the Schumann resonance phenomena and the reconstruction algorithm for source lightning location on the basis of measured Schumann resonance data. The finite difference equations are derived in terms of discretized magnetic fields in the spherical coordinates, introducing the azimuthal symmetry for simplicity. The most reliable electron and neutral density models in the atmosphere and the ionosphere can be used to describe extremely low frequency wave propagation. A linear inverse problem for the reconstruction is formulated using the computed spectra as a set of basis functions to identify lightning distributions with respect to the distances from any observatories to the global thunderstorm centers. Numerical experiments allow us to evaluate properties and precision of the solution in the absence or in the presence of noise in the initial spectral data. The inverse problem is applied to the experimental data collected at a field site in Japan, and distribution of global lightning activity is reconstructed for the data covering the period from March to December 1999. The reconstructed data show a reasonable set of distances from the observatory to well-known global thunderstorm centers, and they indicate the seasonal drift of lightning activity. The problems that were involved in solving the inverse problem are also discussed.
Scientific journal, English

Finite difference analyses of Schumann resonance and reconstruction of lightning distribution
Y. Ando; M. Hayakawa
EMC Zurich, 243-246, Feb. 2005, Peer-reviwed
International conference proceedings, English

New ELF observation system at Moshiri, Japan and assessments of acquired data
Y.Ando; P.Maltsev; A.Sukhynyuk; T.Goto; T.Yamauchi; Y.Hobara; M.Sekiguchi; Y.Ikegami; M.Sera; V.Korepanov; M.Hayakawa
J. Atmos. Electr., 25, 1, 29-39, Jan. 2005, Peer-reviwed
Scientific journal, English

Anomalous effect in Schumann resonance phenomena observed in Japan, possibly associated with the Chi-chi earthquake in Taiwan
M Hayakawa; K Ohta; AP Nickolaenko; Y Ando
ANNALES GEOPHYSICAE, EUROPEAN GEOSCIENCES UNION, 23, 4, 1335-1346, 2005, Peer-reviwed, The Schumann resonance phenomenon has been monitored at Nakatsugawa (near Nagoya) in Japan since the beginning of 1999, and due to the occurance of a severe earthquake (so-called Chi-chi earthquake) on 21 September 1999 in Taiwan we have examined our Schumann resonance data at Nakatsugawa during the entire year of 1999. We have found a very anomalous effect in the Schumann resonance, possibly associated with two large land earthquakes (one is the Chi-chi earthquake and another one on 2 November 1999 (Chic-yi earthquake) with a magnitude again greater than 6.0). Conspicuous effects are observed for the larger Chi-chi earthquake, so that we summarize the characteristics for this event. The anomaly is characterized mainly by the unusual increase in amplitude of the fourth Schumann resonance mode and a significant frequency shift of its peak frequency (similar to 1.0Hz) from the conventional value on the B-y magnetic field component which is sensitive to the waves propagating in the NS meridian plane. Anomalous Schumann resonance signals appeared from about one week to a few days before the main shock. Secondly, the goniometric estimation of the arrival angle of the anomalous signal is found to coincide with the Taiwan azimuth (the unresolved dual direction indicates toward South America). Also, the pulsed signals, such as the Q-bursts, were simultaneously observed with the "carrier" frequency around the peak frequency of the fourth Schumann resonance mode. The anomaly for the second event for the Chia-yi earthquake on 2 November had much in common. But, most likely due to a small magnitude, the anomaly appears one day before and lasts until one day after the main shock, with the enhancement at the fourth Schumann resonance mode being smaller in amplitude than the case of the Chi-chi earthquake. Yet, the other characteristics, including the goniometric direction finding result, frequency shift, etc., are nearly the same. Although the emphasis of the present study is made on experimental aspects, a possible generation mechanism for this anomaly is discussed in terms of the ELF radio wave scattered by a conducting disturbance, which is likely to take place in the middle atmosphere over Taiwan. Model computations show that the South American thunderstorms (Amazon basin) play the leading role in maintaining radio signals, leading to the anomaly in the Schumann resonance.
Scientific journal, English

Finite difference analyses of Schumann resonance and reconstruction of lightning distribution
Y. Ando; M. Hayakawa
2004 International Symposium on Antennas and Propagation, 1E2-3, Aug. 2004, Peer-reviwed
International conference proceedings, English

スプライトの連続光学観測システムの構築
松戸, 亀田; 安藤, 早川
高速信号処理応用技術学会, 7, 2, 29-42, Jun. 2004, Peer-reviwed
Scientific journal, Japanese

A 2-dimensional analysis of Schumann resonances by the finite difference method
Y. Ando; M. Hayakawa
Progress in Electromagnetics Research Symposium, 26b-15, Mar. 2004
International conference proceedings, English

Natural Electromagnetic Phenomena and Electromagnetic Theory: A Review
Masashi Hayakawa; Yoshiaki Ando; Katsumi Hattori
The transactions of the Institute of Electrical Engineers of Japan.A, 124, 1, 72-79, 2004, Peer-reviwed, We review the new findings on natural electromagnetic phenomena in the near-Earth environment and will show the importance of electromagnetic analyses in elucidating the essential points of these phenomena. The topics include (1) atmospheric phenomena related to lightning (e.g. mesospheric optical emissions)
(2) seismo-electromagnetic phenomena (electromagnetic phenomena associated with earthquakes and/or volcano eruptions)
(3) plasma and wave phenomena in the Earth's ionosphere and magnetosphere
and (4) electromagnetic or electrodynamic coupling among different regions. We pay our greatest attention to the unsolved essential problems for each subject, and suggest how electromagnetics would contribute to a solution to those problems. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved.
Scientific journal, English

Numerical analysis on the propagation of ULF/ELF signals in the lithosphere with highly conductive layers
AV Kulchitsky; Y Ando; M Hayakawa
PHYSICS AND CHEMISTRY OF THE EARTH, PERGAMON-ELSEVIER SCIENCE LTD, 29, 4-9, 495-500, 2004, Peer-reviwed, This paper deals with the numerical analyses on the effect of inhomogencities (highly conductive layers) on the propagation of seismogenic electromagnetic signals in the ULF/ELF range. For simplicity of computations we assume that the geometrical configuration is uniform in one direction, which is possibly consistent with the actual situation. We adopt the frequency domain finite difference method in the computation, and calculate the electric field at points where the fields are measurable. Our numerical results show some significant findings: (1) it is necessary to consider the presence of air region in the lithospheric propagation, (2) there exist characteristic frequencies at which we have the effective response at a point due to the presence of the conductive layer, (3) a site closest to the source does not necessarily show the strongest response, depending on the configuration of the layers. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English

2-D Finite Difference Analyses of Schumann Resonance and Identification of Lightning Distribution
Yoshiaki Ando; Masashi Hayakawa
IEEJ Transactions on Fundamentals and Materials, 124, 12, 1225-1231, 2004, Peer-reviwed, The extremely low frequency propagation associated with Schumann resonance phenomena are calculated numerically by the frequency-domain finite difference method, and distribution of source lightnings is identified by solving an inverse problem using the computed spectra as a set of basis functions. The finite difference equations are formulated in terms of discretized magnetic fields in the Cartesian coordinates adopting a cylindrical shell cavity for simplicity. The most reliable electron and neutral density models in the atmosphere and the ionosphere can be used to take into consideration propagation losses. The inverse problem already developed is applied to the measured data to reconstruct lightning activity distribution as a function of distance from the observation point. The reconstructed data successfully show the lightning active season, time, and distance, which are reasonable in comparison with the earlier reports. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved.
Scientific journal, English

An analysis of excitation of magnetostatic surface waves in an in-plane magnetized YIG film by the integral kernel expansion method
Y Ando; N Guan; K Yashiro; S Ohkawa; M Hayakawa
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 51, 2, 492-499, Feb. 2003, Peer-reviwed, We present,a method to solve a kind of integral equations (we call it the integral kernel expansion method), and apply it to an analysis of excitation of magnetostatic surface-wave/magnetostatic backward-volume-wave modes in a magnetized yttrium-iron-garnet film. The Fourier integral of a normal component of magnetic flux density is derived in terms of an unknown current density flowing in a microstrip transducer. The integral kernel is expanded into a series of the Legendre polynomials and expansion of the unknown current density in terms of appropriate functions reduces the Fourier integral to a system of linear equations with unknown coefficients. Determination of the unknown coefficients allows us to estimate the power of magnetostatic waves, which characterizes the excitation. It is found that our numerical method is superior to the previous conventional method based on an assumed current density. In order to verify the validity of our method, we compare our results with the corresponding experiments, and we have found good agreement between the two.
Scientific journal, English

Theoretical analysis on the penetration of power line harmonic radiation into the ionosphere
Y Ando; M Hayakawa; OA Molchanov
RADIO SCIENCE, AMER GEOPHYSICAL UNION, 37, 6, Nov. 2002, Peer-reviwed, [1] Radiation at the fundamental and higher harmonic frequencies from power lines affects the environment of Earth's ionosphere and magnetosphere, because such radiation may lead to the enhanced electron precipitation into the ionosphere due to wave-particle interactions in the magnetosphere. In this paper we analyze theoretically the penetration of power line radiation, taking into account the presence of the anisotropic, homogeneous ionosphere. The electromagnetic field can be formulated by using the Fourier transform and field distribution obtained by proper deformation of the integral path with consideration of singularities. We calculate the field distribution as a function of altitude and distance from the source. From the numerical results, we can find several new findings: (1) the effect of the radiation from power line is limited in a relatively narrow region below the cutoff frequency of the guided mode in the Earth-ionosphere waveguide, while the region affected by the power line radiation becomes much wider if the guided modes exist, (2) the radiated fields are directed almost horizontally, and (3) the altitude distribution of electromagnetic fields changes at the ion gyrofrequency. Comparison with the observed data shows a good agreement with respect to the region affected by power line radiation.
Scientific journal, English

An analysis of excitation of magnetostatic surface waves in an in-plane magnetized YIG film
Y. Ando; M. Hayakawa
2002 Interim International Symposium on Antennas and Propagation, Yokosuka, Japan, 544-547, Nov. 2002
International conference proceedings, English

An analysis on excitation of magnetostatic surface waves by the measured equation of invariance
Y. Ando; M. Hayakawa
2002 Asia-Pacific Microwave Conference, Kyoto, Japan, WEOF-57, Nov. 2002
International conference proceedings, English

Theoretical analysis on the penetration of power line harmonic radiation into the Ionosphere
Y. Ando; M. Hayakawa
URSI XXVII General Assembly, Maastricht, Netherlands, E7-539, Aug. 2002, Peer-reviwed
International conference proceedings, English

Analysis on Excitation of Magnetostatic Surface Waves by Asymmetric Coplanar Waveguide Transducers
Y. Ando; M. Hayakawa
2001 Asia Pacific Radio Science Conference, B3-2, Aug. 2001
International conference proceedings, English

Theoretical Analysis on the Penetration of Power Line Harmonic Radiation into the Ionosphere
Y. Ando; M. Hayakawa
0, Jul. 2001
International conference proceedings, English

Theoretical Analysis on the Penetration of Power Line Harmonic Radiation into the Ionosphere
Y. Ando; M. Hayakawa
2001 Asia Pacific Radio Science Conference, E9, Jul. 2001
International conference proceedings, English

Excitation of magnetostatic surface waves in an in-plane magnetized YIG film
Y. Ando; M. Hayakawa
IV International Symposium on Electromagnetic Compatibility and Electromagnetic Ecology(EMC-2001), 126-130, Jun. 2001
International conference proceedings, English

Excitation of magnetostatic surface waves in an in-plane magnetized YIG film
Y. Ando; N. Guan; K. Yashiro; S. Ohkawa
2000 Asia-Pacific Microwave Conference Proceedings, 345-348, 2000
International conference proceedings, English

Excitation of magnetostatic surface waves by slot line transducers
Y Ando; N Guan; K Yashiro; S Ohkawa
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E82C, 7, 1123-1128, Jul. 1999, Excitation of magnetostatic surface waves by slot line transducers is analyzed by using the integral kernel expansion method. The Fourier integral for the current density is derived in terms of an unknown normal component of the magnetic flux density in a slot region. The integral kernel is expanded into a series of orthogonal polynomials and then applying Galerkin's method to the resulting equation yields a system of linear equations for the unknown coefficients. Comparison of a numerical result by the present method with an experiment is in good agreement.
Scientific journal, English

Effects of a Metal Plane on MSSW/MSBVW Modes in a YIG Film
Y.Ando; N.Guan; K.Yashiro; S.Ohkawa
INTERMAG '99, -, May 1999
International conference proceedings, English

Excitation of Magnetostatic Surface Waves by Slot Line Transducers
Y.Ando; N.Guan; K.Yashiro; S.Ohkawa
Asia-Pacific Microwave Conference '98, -, Dec. 1998
International conference proceedings, English

Excitation of magnetostatic surface wave by coplanar waveguide transducers
Y Ando; N Guan; K Yashiro; S Ohkawa
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E81C, 12, 1942-1947, Dec. 1998, Peer-reviwed, Excitation of magnetostatic surface waves by coplanar waveguide transducers is analyzed by using the integral kernel expansion method. The Fourier integral for the current density is derived in terms of an unknown normal component of the magnetic flux density on slot region of a coplanar waveguide. The integral kernel is expanded into a series of Legendre polynomials and then applying Galerkin's method to the unknown held reduces the Fourier integral to a system of linear equations for the unknown coefficients. In this process, we should take into account the edge conditions which show nonreciprocal characteristics depending on frequency. The present method shows excellent agreement with experiments.
Scientific journal, English

Excitation of magnetostatic surface waves by coplanar waveguide transducers
Y Ando; N Guan; K Yashiro; S Ohkawa
1997 ASIA-PACIFIC MICROWAVE CONFERENCE PROCEEDINGS, VOLS I-III, CITY UNIVERSITY HONG KONG, 17-20, 1997, Excitation of magnetostatic surface waves by a coplanar waveguide transducer is analyzed by the integral kernel expansion method. An integral equation for an unknown normal component of the magnetic flux density on slot region of a coplanar waveguide is derived through the:Fourier transform. The integral kernel is expanded in terms of orthogonal polynomials and then applying Galerkin's method to the unknown field reduces the integral equation to a system of algebraic equations for the unknown coefficients. The radiation resistance which characterizes the excitation is calculated as a function of frequency, and comparison of the theory with experiments is in good agreement.
International conference proceedings, English

CIP-BS formulation for electromagnetic simulation
TAKAHASHI Yuusuke; ANDO Yoshiaki
15 Nov. 2012, 電気学会研究会資料. EMT, 電磁界理論研究会, 2012, 151, 121-126, Japanese, 10031128996, AN00346578

Numerical consideration on identification of electron density profile by using VLF wave propagation in the Earth-ionosphere waveguide
ITO Hitoshi; ANDO Yoshiaki
15 Nov. 2012, 電気学会研究会資料. EMT, 電磁界理論研究会, 2012, 175, 43-48, Japanese, 10031129005, AN00346578

An efficient FDTD analysis of VLF wave propagation in the earth-ionosphere waveguide
伊藤 仁; 安藤 芳晃
電子情報通信学会, 21 Jul. 2011, IEICE technical report, 111, 147, 211-215, Japanese, 0913-5685, 40018945133

An efficient FDTD analysis of VLF wave propagation in the earth-ionosphere waveguide
伊藤 仁; 安藤 芳晃
電子情報通信学会, 21 Jul. 2011, IEICE technical report, 111, 148, 211-215, Japanese, 0913-5685, 40018945182

Computational method for electromagnetic field analysis by using CIP-BS
ANDO Yoshiaki; TAKAHASHI Yusuke
11 Nov. 2010, 電気学会研究会資料. EMT, 電磁界理論研究会, 2010, 132, 39-42, Japanese, 10027631824, AN00346578

B-1-46 A Consideration on Effects of Ionospheric Perturbation on VLF propagation by 3D-FDTD method
Machii Noritoyo; Ando Yoshiaki; Hayakawa Masashi
The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2010, Proceedings of the IEICE General Conference, 2010, 1, 46-46, Japanese, 110007883094, AN10471452

C-1-33 Electromagnetic Field Analysis of a Quasi-Multipath Enviroment Using the Mode Matching Method
Horiguchi Masaki; Ando Yoshiaki
近年、多重散乱環境に強い情報伝送方式としてMultiple-Input Multiple-Output(MIMO)が盛んに研究されている。実際にMIMO伝送方式を移動端末に適用した際、端末の特性評価を行うには多重散乱環境を擬似的に構築する必要がある。本研究では、周囲を金属で囲った擬似多重散乱環境をモード整合法[1]によって電磁界解析し、その特性の導出を行う。, The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2010, Proceedings of the IEICE General Conference, 2010, 1, 33-33, Japanese, 110007870949, AN10471452

C-1-17 A Study of Long Propagation Characteristics of the Earth-Ionosphere Waveguide by 2D-FDTD
Obuchi Tatsuya; Ando Yosiaki; Machii Noritoyo; Hayakawa Masashi
The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2010, Proceedings of the IEICE General Conference, 2010, 1, 17-17, Japanese, 110007870933, AN10471452

C-1-15 Analysis of Transmission and Reflection Coefficient for Split-ring Periodic Structure by FDTD Method with CTW incident wave
Higo Eiji; Ando Yoshiaki
The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2010, Proceedings of the IEICE General Conference, 2010, 1, 15-15, Japanese, 110007870931, AN10471452

CS-1-9 CIP-BS Method as an Electromagnetic Field Solver
Noba Akira; Murakoshi Satoi; Ando Yoshiaki
数値電磁界解析においては有限差分時間領域(FDTD)法が一般的に用いられているが、離散化による誤差は常に存在している問題である。一方で、空間の離散間隔を少なくしても精度が保てる手法が存在すれば、同程度の精度でメモリを少なくすることが可能となる。本研究では、新しい電磁界解析の手法としてConstrained Interpolation Prome-Basis Set(CIP-BS)法に着目し、その電磁界解析への応用を目的とする。CIP-BS法は、解を値および微係数に対応した有限のサポートを持つ基底関数系で近似展開する数値計算手法である。本研究ではCIP-BS法を1次元Maxwellの方程式に適用し、様々な時間、空間配置で差分化した計算結果を比較した。, The Institute of Electronics, Information and Communication Engineers, 2010, Proceedings of the IEICE General Conference, "S-32"-"S-33", Japanese, 110007871234, AN10471452

An analysis on perturbations of the Earth-Ionosphere waveguide propagation in the VLF band by using FDTD method
ANDO Yoshiaki; MACHII Noritoyo; HAYAKAWA Masashi
27 Nov. 2009, 電気学会研究会資料. EMT, 電磁界理論研究会, 2009, 124, 79-83, Japanese, 10026374254, AN00346578

C-1-21 2D-CIP solutions for scattering problems using the TF/SF boundary
Murakoshi Satoi; Ando Yoshiaki; Hayakawa Masashi
The Institute of Electronics, Information and Communication Engineers, 02 Sep. 2008, Proceedings of the Society Conference of IEICE, 2008, 1, 21-21, Japanese, 110007101103, AN10489017

太陽フレアによるVLF帯電波伝搬異常の観測結果及びFDTD法による伝搬シミュレーション
轟 悦男; 早川 正士; 安藤 芳晃
10 Mar. 2006, 大気電気研究, 68, 91-92, Japanese, 0286-3405, 10019160570, AA11170358

Analysis on Schumann resonance by FDFD method and identification of global lightning activity distribution
ANDO Yoshiaki; HAYAKAWA Masashi; SHVETS Alexander V.
29 Sep. 2004, 電気学会研究会資料. : The Papers of Technical Meeting on Electromagnetic Theory, IEE Japan. EMT, 電磁界理論研究会, 2004, 90, 55-58, Japanese, 10013609250, AN00346578

Identification of global lightning activity distribution by measuring Schumann resonance
ANDO Yoshiaki; HAYAKAWA Masashi; SHVETS Alexander V.
04 Jun. 2004, 電気学会研究会資料. : The Papers of Technical Meeting on Electromagnetic Theory, IEE Japan. EMT, 電磁界理論研究会, 2004, 40, 19-23, Japanese, 10013270474, AN00346578

地震に伴うVLF/LF大地・電離層導波管伝搬異常の解析
前川 慎光; 安藤 芳晃; 早川 正士
22 Mar. 2004, 大気電気研究, 64, 119-120, Japanese, 0286-3405, 10012964802, AA11170358

A Numerical Analysis on the Effect of Power Line Harmonic Radiation on the Ionosphere
ANDO Yoshiaki; HAYAKAWA Masashi
30 May 2003, 電気学会研究会資料. EMT, 電磁界理論研究会, 2003, 20, 23-26, Japanese, 10012551935, AN00346578

電気理論
文部科学省
Contributor, 第４章 電気機器, 海文堂, Feb. 2023

VLF帯伝搬の電界変動を用いた電子密度同定法の現実的電離圏モデルへの適用
入江俊行; 安藤芳晃
Oral presentation, Japanese, 電子情報通信学会エレクトロニクスシミュレーション研究会
26 Jan. 2024
25 Jan. 2024- 26 Jan. 2024

3次元電磁界シミュレーションを用いた地震に関するULF電磁放射の解析
真野里奈子; 安藤芳晃
Oral presentation, Japanese, 日本大気電気学会第102回研究発表会
07 Jan. 2024
06 Jan. 2024- 07 Jan. 2024

太陽光散乱シミュレーションによる極中間圏雲のパラメタ抽出法の研究
桜谷竜司; 安藤芳晃; 津田卓雄
Oral presentation, Japanese, 日本大気電気学会第102回研究発表会
07 Jan. 2024
06 Jan. 2024- 07 Jan. 2024

VLF帯伝搬の時間変動を用いた下部電離圏電子密度推定の数値的検証
入江俊行; 安藤芳晃
Oral presentation, 日本大気電気学会第102回研究発表会
07 Jan. 2024
06 Jan. 2024- 07 Jan. 2024

Temperature retrieval in the middle atmosphere using Himawari-8/AHI limb- sounding data
津田卓雄; 安藤芳晃; 中川広務; Ward William; 堤雅基; 穂積裕太; 細川敬祐; 村田健史
SGEPSS2023秋季年会
26 Sep. 2023
24 Sep. 2023- 27 Sep. 2023

An identification of electron density profile in the lower ionosphere by using a temporal variation of VLF earth-ionosphere waveguide propagation
Toshiyuki Irie; Yoshiaki Ando
Oral presentation, 3rd International Symposium of Space Science and Radio Engineering
29 Aug. 2023
28 Aug. 2023- 29 Aug. 2023

Simulation of ULF emissions in the Earth's crust by 3-D WLP-FDTD method
Rinako Shinno; Yoshiaki Ando
Oral presentation, Japanese, 電子情報通信学会エレクトロニクスシミュレーション研究会
20 Jul. 2023
20 Jul. 2023- 21 Jul. 2023

A consideration on the identification of electron density in the D-layer using electric field variation of the VLF/LF earth-ionosphere waveguide propagation
入江俊行; 安藤芳晃
Poster presentation, Japanese, Japan Geoscience Union Meeting 2023 (JpGU2023)
22 May 2023
21 May 2023- 26 May 2023

VLF帯大地-電離圏導波管伝搬の時間変動を用いた静穏時下部電離圏の電子密度同定
入江俊行; 安藤芳晃
Oral presentation, Japanese, 電子情報通信学会エレクトロニクスシミュレーション研究会
19 May 2023
19 May 2023- 19 May 2023

VLF帯大地-電離圏導波管伝搬の日変化パタンを用いた静穏時の電離圏下部電子密度の同定
入江俊行,安藤芳晃
Poster presentation, Japanese, 日本大気電気学会第101回研究発表会, 日本大気電気学会, 東京
07 Jan. 2023

Variations in polar mesospheric clouds observed by Himawari-8/AHI
津田卓雄; 三好勉信; 穂積裕太; 安藤芳晃; 細川敬祐; 鈴木秀彦; 村田健史; 中村 卓司
地球電磁気・地球惑星圏学会第152回講演会
06 Nov. 2022
03 Nov. 2022- 07 Nov. 2022

Numerical Simulation of ULF Fields Generated by Subsurface Electric Currents and Examination of the Correlation between Current Intensity and Magnitude of Earthquake
Yoshiaki Ando; Ryota Kimura; Katsumi Hattori; Masashi Hayakawa
Invited oral presentation, English, 2022 URSI-Japan Radio Science Meeting, Invited, International conference
02 Sep. 2022

ひまわり PMC 観測の紹介
津田卓雄; 穂積裕太; 安藤芳晃; 細川敬祐; 鈴木秀彦; 村田健史; 中村卓司; 三好勉信
Oral presentation, Japanese, 宇宙空間からの地球超高層大気観測に関する研究会, Domestic conference
Sep. 2022

WLP-FDTD 法を用いた地殻変動に伴う ULF 帯電磁放射の波源電流強度推定の高精度化
木村亮太; 安藤芳晃; 服部克巳; 早川正士
Oral presentation, Japanese, 大気電気学会誌, Domestic conference
08 Jan. 2022

磁化プラズマをE-J法でモデル化したVLF/LF帯電波の３次元汎用シミュレータの開発
栗原優介; 安藤芳晃
Oral presentation, Japanese, 大気電気学会誌, Domestic conference
07 Jan. 2022

Detection of polar mesospheric clouds utilizing Himawari-8/AHI full-disk images
T. T. Tsuda; Y. Hozumi; Y. Ando; K. Hosokawa; H. Suzuki; K. T. Murata; T. Nakamura; J. Yue; K. Nielsen; Y. Miyoshi
Oral presentation, English, AGU Fall Meeting, International conference
17 Dec. 2021

Structure tracking of polar mesospheric clouds by the meteorological satellite, Himawari-8
Yuta Hozumi; Takuo T. Tsuda; Yoshiaki Ando; Keisuke Hosokawa; Hidehiko Suzuki; Takeshi Murata; Takuji Nakamura
Oral presentation, English, AGU Fall Meeting, International conference
17 Dec. 2021

Numerical estimation of source current intensity causing ULF emission associated with earthquakes and correlation with the earthquake magnitude
Ryota Kimura; Yoshiaki Ando; Masashi Hayakawa; Katsumi Hattori
Poster presentation, English, Japan Geoscience Union Meeting (JpGU), International conference
06 Jun. 2021

静止軌道衛星ひまわりで観測された極中間圏雲の年々変化
白 秉安; 津田 卓雄; 鈴木 秀彦; 穂積 裕太; 安藤 芳晃; 細川 敬祐; 中村 卓司; 村田 健史
Poster presentation, Japanese, Japan Geoscience Union Meeting 2021 (JpGU), Domestic conference
04 Jun. 2021

散乱体が疎に分布した散乱問題におけるCIP-BS法の計算効率の検討
星野, 安藤
Oral presentation, Japanese, 2021年電子情報通信学会総合大会, オンライン, Domestic conference
09 Mar. 2021

WLP-FDTD法を用いた地殻変動に伴うULF帯電磁放射の波源電流強度の推定
木村亮太; 安藤芳晃
Oral presentation, Japanese, 大気電気学会誌, Domestic conference
09 Jan. 2021

VLF/LF帯導波管伝搬のFDTDシミュレーションによる電離圏電子密度同定手法の数値解析
寺山透星; 安藤芳晃
Oral presentation, Japanese, 大気電気学会誌, Domestic conference
08 Jan. 2021

Real-time monitoring of polar mesospheric clouds utilizing Himawari-8 full disk images
津田卓雄; 穂積裕太; 安藤芳晃; 細川敬祐; 鈴木秀彦; 中村卓司; 村田健史
Oral presentation, Japanese, 第148回地球電磁気・地球惑星圏学会講演会, Domestic conference
03 Nov. 2020

Polar mesospheric cloud structure tracking with data from the meteorological satellite Himawari-8
穂積裕太; 津田卓雄; 安藤芳晃; 細川敬祐; 鈴木秀彦; 中村卓司; 村田健史
Oral presentation, Japanese, 第148回地球電磁気・地球惑星圏学会講演会, Domestic conference
03 Nov. 2020

Numerical simulation of polar mesospheric cloud emissions observed by Himawari-8
安藤芳晃; 津田卓雄; 穂積裕太; 細川敬祐; 鈴木秀彦; 中村卓司; 村田健史
Oral presentation, Japanese, 第148回地球電磁気・地球惑星圏学会講演会, Domestic conference
03 Nov. 2020

中間圏雲の発生と磁気圏からの高エネルギー電子降下の関連について
細川敬祐; 津田卓雄; 穂積裕太; 安藤芳晃; 鈴木秀彦; 中村卓司; 村田健史
Oral presentation, Japanese, 第148回地球電磁気・地球惑星圏学会講演会, Domestic conference
03 Nov. 2020

Numerical Analysis on Electromagnetic Wave Propagation in VLF/LFEarth-Ionosphere Waveguide by 3D FDTD Method in the SphericalCoordinates
Tosei Terayama; Yoshiaki Ando
Oral presentation, Japanese, JpGU-AGU Joint Meeting 2020, International conference
Jul. 2020

Numerical simulation of ULF electromagnetic wave propagation in thelithosphere associated with earthquakes by using the WLP-FDTDmethod
Ryota Kimura; Yoshiaki Ando; Katsumi Hattori
Oral presentation, English, JpGU-AGU Joint Meeting2020
Jul. 2020

3次元球座標系FDTD法によるVLF/LF帯大地-電離圏導波管伝搬シミュレーション法の開発
関根, 安藤
Oral presentation, Japanese, 大気電気学会 第97回研究発表会
Jan. 2019

CIP Basis Set Method for Electromagnetic Simulation
Y. Ando
Oral presentation, English, 50th Anniversary International Symposium of Center for Space Science and Radio Engineering, 電気通信大学宇宙・電磁環境研究センター, 電気通信大学, International conference
26 Jun. 2018

VLF/LF帯大地-電離圏導波管伝搬の電磁界シミュレーションと電子密度プロファイル推定の数値検討
安藤, 伊藤
Oral presentation, Japanese, 電気通信大学宇宙・電磁環境研究センター研究集会, 電気通信大学宇宙・電磁環境研究センター, 電気通信大学, Domestic conference
20 Dec. 2012

VLF帯大地-電離層導波管伝搬を用いた電子密度プロファイル同定手法の検討
伊藤, 安藤
Oral presentation, Japanese, 2012年電子情報通信学会総合大会,2012年電子情報通信学会総合大会
Mar. 2012

2次元CIP-BS法における各種個別技術の開発－PMLと不均質媒質中の伝搬－
高橋, 安藤
Oral presentation, Japanese, 2012年電子情報通信学会総合大会,2012年電子情報通信学会総合大会
Mar. 2012

FDTD法を用いたVLF帯大地-電離層導波管伝搬の解析
安藤; 待井, 大渕
Oral presentation, Japanese, 2010年電気学会基礎・材料・共通部門大会, Domestic conference
Sep. 2010

CTW入射波を用いたFDTD法によるsplit-ring周期構造の透過･反射特性の解析
比護, 安藤
Oral presentation, Japanese, 2010年電子情報通信学会総合大会,2010年電子情報通信学会総合大会
Mar. 2010

2次元FDTD法によるVLF帯大地電離層導波管の長距離伝搬の解析
大渕, 安藤; 待井, 早川
Oral presentation, Japanese, 2010年電子情報通信学会総合大会,2010年電子情報通信学会総合大会
Mar. 2010

基底関数展開を用いたCIP法による電磁界解析の検討
野場; 村越, 安藤
Oral presentation, Japanese, 2010年電子情報通信学会総合大会,2010年電子情報通信学会総合大会
Mar. 2010

モード整合法を用いた擬似多重散乱環境の電磁界解析
堀口, 安藤
Oral presentation, Japanese, 2010年電子情報通信学会総合大会,2010年電子情報通信学会総合大会
Mar. 2010

3次元FDTD法によるVLF帯大地・電離層導波管伝搬異常の解析
待井; 安藤, 早川
Oral presentation, Japanese, 2010年電子情報通信学会総合大会,2010年電子情報通信学会総合大会
Mar. 2010

金属平板に周期孔を設けたときのFDTD解析
菅井, 安藤
Oral presentation, Japanese, 平成22年電気学会全国大会,平成22年電気学会全国大会
Mar. 2010

二次元FDFD法における最適なマルチパス環境の作成と評価
淀川, 安藤
Oral presentation, Japanese, 平成22年電気学会全国大会,平成22年電気学会全国大会
Mar. 2010

電磁界解析を用いた周囲環境がRFIDに及ぼす影響の検討
前田, 安藤
Oral presentation, Japanese, 平成22年電気学会全国大会,平成22年電気学会全国大会
Mar. 2010

CIP-BS法の電磁界解析への適用
村越, 安藤
Oral presentation, Japanese, 平成22年電気学会全国大会,平成22年電気学会全国大会
Mar. 2010

FDTD法を用いたVLF帯大地-電離層導波管伝搬異常の解析
安藤; 待井, 早川
Oral presentation, Japanese, 電磁界理論研究会
Nov. 2009

CTW入射波を用いた周期孔のある金属平板に対する透過反射特性のFDTD解析
菅井; 安藤, 早川
Oral presentation, Japanese, 電磁界理論研究会,電磁界理論研究会
May 2009

3次元FDTD法によるELF/VLF帯大地-電離層導波管伝搬の解析
待井; 安藤, 早川
Oral presentation, Japanese, 電磁界理論研究会,電磁界理論研究会
Nov. 2008

CIP法によるTF/SF境界を用いた多次元散乱問題の解法
村越; 安藤, 早川
Oral presentation, Japanese, 電磁界理論研究会
Nov. 2008

CIP法によるTF/SF境界を用いた2次元散乱問題の解法
村越; 安藤, 早川
Oral presentation, Japanese, 電子情報通信学会 ソサイエティ大会,ソサイエティ大会
Sep. 2008

3次元FDTD法によるELF/VLF帯大地-電離層導波管伝搬の解析
待井; 安藤, 早川
Oral presentation, Japanese, 電気学会 基礎・材料・共通部門大会,基礎・材料・共通部門大会
Aug. 2008

超伝導シールド層の接地位置の違いによる相互インダクタンスの変化
柏, 守屋; 宇佐美; 小林; 和田; 安藤; 陳, 水柿
Oral presentation, Japanese, 2007年電子情報通信学会総合大会, Domestic conference
22 Mar. 2007

GAを用いた広帯域マイクロストリップ線路BPFの設計に関する一考察
安藤, 和田; 水柿; 陳, 谷井
Oral presentation, Japanese, 電子情報通信学会マイクロ波研究会,電子情報通信学会マイクロ波研究会
Mar. 2007

1次元CIP法における完全TF/SF境界
齊藤; 安藤, 早川
Oral presentation, Japanese, 電子情報通信学会総合大会,電子情報通信学会総合大会
Mar. 2007

2次元M型CIP法の数値分散に関する検討
安藤, 和田; 水柿; 陳, 早川
Oral presentation, Japanese, 電子情報通信学会総合大会,電子情報通信学会総合大会
Mar. 2007

最適PML導電率プロファイルパラメタ探索の検討
小林; 安藤, 早川
Oral presentation, Japanese, 電子情報通信学会総合大会,電子情報通信学会総合大会
Mar. 2007

適応アレーアンテナを用いた人体頭部曝露低減に関する検討
小坂; 安藤, 早川
Oral presentation, Japanese, 電子情報通信学会総合大会,電子情報通信学会総合大会
Mar. 2007

Natural Electromagnetic Phenomena and Electromagnetic Theory
自然電磁気現象解明と電磁界解析調査専門委員会
Others, English, 自然電磁気現象解明と電磁界解析調査専門委員会,電気学会技術報告 第1065号
Oct. 2006

2次元散乱問題へのCIP法の適用に関する検討
安藤, 早川
Oral presentation, Japanese, 電気学会 電磁界理論研究会,電気学会 電磁界理論研究会
Oct. 2006

CIP法におけるTotal-Field/Scattered-Field境界の適用
安藤, 早川
Oral presentation, Japanese, 電子情報通信学会ソサイエティ大会,電子情報通信学会ソサイエティ大会
Sep. 2006

シューマン共振現象による広域雷分布推定
安藤, 早川
Oral presentation, Japanese, 電気学会 基礎・材料・共通部門大会,平成18年電気学会 基礎・材料・共通部門大会
Aug. 2006

CIP法におけるTotal-Field/Scattered-Field境界の適用
安藤
Oral presentation, Japanese, 電気学会電磁界理論研究会,電磁界理論研究会
May 2006

CIP法のアンテナ解析への適用に関する検討
安藤; 早川
Oral presentation, Japanese, 電気学会電磁界理論研究会,電磁界理論研究会
Nov. 2005

吸収境界条件としてのCIP法と1次元BPL-FDTD法への適用
安藤; 早川
Oral presentation, Japanese, 電子情報通信学会ソサイエティ大会,2005年ソサイエティ大会
Sep. 2005

電力線高調波の電離層への透過の数値解析
安藤; 早川
Oral presentation, Japanese, 電気学会基礎・材料・共通部門大会,基礎・材料・共通部門大会
Aug. 2005

シューマン共振を用いた世界雷分布同定
安藤; 早川
Oral presentation, Japanese, 電気学会基礎・材料・共通部門大会,基礎・材料・共通部門大会
Aug. 2005

有限差分法によるシューマン共振の解析と広域雷活動分布の推定
安藤, 早川
Invited oral presentation, Japanese, 地球惑星科学関連学会2005年合同大会
May 2005

MEI法を用いたマイクロストリップ線路の解析
任田; 安藤, 早川
Oral presentation, Japanese, 日本大気電気学会研究発表会
Jan. 2005

FDTD法による人体が電波伝搬に与える影響の検討
小坂; 安藤, 早川
Oral presentation, Japanese, 日本大気電気学会研究発表会
Jan. 2005

有限差分法によるシューマン共振の解析と広域雷活動分布の推定
安藤; 早川
Oral presentation, Japanese, 日本大気電気学会研究発表会
Jan. 2005

有限差分法によるシューマン共振の解析と広域雷活動位置の推定
安藤, 早川; A.V.Shvets
Oral presentation, Japanese, 電気学会 電磁界理論研究会
Sep. 2004

シューマン共振を用いた広域雷活動位置の推定
安藤, 早川; A. Shvets
Oral presentation, Japanese, 電気学会 電磁界理論研究会
Jun. 2004

有限差分法によるシューマン共振現象の数値解析
安藤, 早川
Oral presentation, Japanese, 大気電気研究
Jan. 2004

電離層電流による地表面付近電磁界の解析
小川; 安藤, 早川
Oral presentation, Japanese, 大気電気研究
Jan. 2004

MEI法を用いたマイクロストリップの不連続部からの放射について
任田; 安藤, 早川
Oral presentation, Japanese, 大気電気研究
Jan. 2004

屈曲部を有する伝送線路からの放射の解析
新保; 安藤, 早川
Oral presentation, Japanese, 大気電気研究
Jan. 2004

Numerical analysis on the propagation of ULF/ELF signals in the lithosphere with highly conductive layers
クルチツキー; 安藤, 早川
Oral presentation, English, 電磁環境研究会, 東京
28 Nov. 2003

Numerical analysis on the propagation of ULF/ELF signals in the Lithosphere with Highly Conductive Layers
A. Kulchitsky; 安藤, 早川
Oral presentation, Japanese, 電気学会 電磁界理論研究会
Nov. 2003

有限差分法を用いたシューマン共振現象の解析
安藤, 早川
Oral presentation, Japanese, 電気学会 電磁界理論研究会
Nov. 2003

電力線高調波の電離層への透過の数値解析
安藤, 早川
Oral presentation, Japanese, 電気学会 電磁界理論研究会
Jul. 2003

電力線高調波の電離層への影響の数値解析
安藤, 早川
Oral presentation, Japanese, 電気学会 電磁界理論研究会
May 2003

電力線高調波の電離層への透過特性
安藤, 早川
Oral presentation, Japanese, 日本大気電気学会第68回研究発表会
Jan. 2003

電力線高調波の電離層への透過特性
安藤, 早川
Oral presentation, Japanese, 電気学会 電磁環境研究会
Jan. 2003

MEI法を用いた静磁表面波の解析
安藤, 早川
Oral presentation, Japanese, 電気学会 電磁界理論研究会
Oct. 2002

MEI法を用いた静磁表面波の解析
安藤, 早川
Oral presentation, Japanese, 電気学会 基礎・材料・共通部門大会
Sep. 2002

電力線高調波の電離層への透過特性
安藤, 早川
Oral presentation, Japanese, 電気学会 基礎・材料・共通部門大会
Sep. 2002

多素子トランスデューサによる静磁表面波の励振
安藤, 官; 八代; 大川, 早川
Oral presentation, Japanese, 2001年 電子情報通信学会 総合大会
Mar. 2001

YIG膜面内に磁化したときの静磁表面波の励振の解析
安藤, 官; 八代, 大川
Oral presentation, Japanese, 電子情報通信学会 2000年 総合大会
Mar. 2000

スロット線路を用いた静磁表面波の励振の解析
安藤, 官; 八代, 大川
Oral presentation, Japanese, 電子情報通信学会 '98 総合大会
Mar. 1998

コプラナー型MSSW S/Nエンハンサ
安藤, 官; 八代, 大川
Oral presentation, Japanese, 電子情報通信学会 '97 総合大会,
Mar. 1997

コプラナー型 MSSW S/Nエンハンサ
安藤, 官; 八代, 大川
Oral presentation, Japanese, 電子情報通信学会 '97 総合大会,
Mar. 1997

Electromagnetic Wave Engineering
Present
The University of Electro-Communications

Electromagnetism Ⅰ
Present
The University of Electro-Communications

Advanced Transmission Engineering
Present
The University of Electro-Communications

宇宙通信工学
The University of Electro-Communications

電子工学工房
The University of Electro-Communications

総合コミュニケーション科学
The University of Electro-Communications

電子情報通信学会

IEEE

The Institute of Electrical Engineers of Japan

地殻変動に伴う電磁雑音の電磁界解析法確立とメカニズム解明への貢献
安藤 芳晃
日本学術振興会, 科学研究費助成事業 基盤研究(C), 電気通信大学, 基盤研究(C), 23K03789
Apr. 2023 - Mar. 2026

静止軌道衛星ひまわりを活用した夜光雲の特性量推定と地上光学連携観測による検証
津田 卓雄; 安藤 芳晃; 穂積 裕太; 鈴木 秀彦; 西山 尚典; 野澤 悟徳; 斎藤 徳人; 川原 琢也; 細川 敬祐
日本学術振興会, 科学研究費助成事業 基盤研究(B), 電気通信大学, 基盤研究(B), ひまわり 8 号による全球輝度画像データから夜光雲を自動検出する手法の開発を進めた. 輝度値の小さい (暗い) 夜光雲も検出する為に, 背景光成分に含まれる大気分子のレイリー散乱光成分を再現・除去した後に閾値判定で夜光雲/極中間圏雲による散乱光を抽出する方法を考案し, 検出感度を向上させた. 本手法で自動検出した夜光雲データの検証として, 夜光雲観測で実績のある NASA の低軌道人工衛星 Aeronomy of Ice in the Mesosphere (AIM) の夜光雲観測データと比較した結果, 非常に良い一致が見られ, 本手法の十分な有効性が示された. 以上の研究成果について論文として纏め, 学術雑誌にて発表した [Tsuda et al., ESS, 2022]. 並行して, ひまわり 8 号で観測される夜光雲構造の時空間変動を解析し, 夜光雲の構造追跡を行うことで, 背景大気の風速 (追跡風速) を推定する手法の開発も進めた. 推定手法の検証として, 推定した追跡風速の平均成分が中間圏界面付近 (夜光雲発生領域) の基本的な平均風速と概ね一致することを確認し, 本手法の妥当性が示された. 追跡風速の変動成分 (大気波動成分) については, 1 日 (24 時間) 周期成分, 半日 (12 時間) 周期成分に加え, 14.8 時間周期成分が観測された. このような夜光雲の地方時変動特性の観測は, ひまわり 8 号の静止軌道を活かした独自の観測であり, 夜光雲観測に新しい視点を提供する意義があると考える. 以上の研究成果について論文として纏め, 学術雑誌にて発表した [Hozumi et al., JGR, 2021]., 21H01144
Apr. 2021 - Mar. 2025

Development of numerical simulation of ULF electromagnetic wave propagation in the lithosphere and its application to global electromagnetic environment problems
安藤 芳晃
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), Douglas-Gunn(DG)アルゴリズムに基づくWeighted Laguerre Polynomial - Finite Difference Time Domain (WLP-FDTD)法の効率的解法について、精度良く求めるためのパラメタのチューニングを行った。DGアルゴリズムは摂動項を取り入れることによる誤差が生じるが、特に本研究で行う波源からの距離が波長に比べて極めて短い場合に誤差が大きいことが分かった。これを解消するためには、WLP関数の伸縮を決めるスケールパラメタを大きくとり、また結果として展開次数を多くすることで誤差を軽減できることが判明した。特に、大気を含む導電率が小さい媒質が存在することでスケールパラメタを数千、展開次数を数十万ととる必要があることが分かった。これらについては計算量が多くなるものの、並列化によって計算時間は短縮できるので大きな問題ではないと言える。 また開発したWLP-FDTD法を用いた地殻変動に伴う電磁放射の検討であるが、2次元解析で引き続き行っており、これによって電磁放射を引き起こす波源電流強度が地震の規模（マグニチュード）と相関をもつことが分かった。11のイベントについて解析を行い、9のイベントで良い相関が得られたと言える。精度よいシミュレーションのためにはいくつか克服すべき点があった。一つは吸収境界条件の開発であり、Perfectly Matched Layer (PML)だけでは低周波側での吸収性能が悪いことが判明した。低周波数でも性能よく動作する「不均一メッシュ＋PML複合吸収境界条件」を開発した。克服すべき点のもう一つは地下導電率構造のモデル化であり、現時点で最も広範囲で精度のよいグローバル導電率モデルを導入し、この不確定性をカバーできるシミュレーションを確立した。, 20K04412
Apr. 2020 - Mar. 2023

Development of a global and real-time monitoring method for electron density profiles of the lower ionosphere by using the VLF/LF wave propagation
Ando Yoshiaki
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), A numerical consideration on a monitoring method of electron density profile in sub-ionospheric layer has been performed. A numerical method to model the VLF/LF earth-ionosphere waveguide propagation was developed. Then, an identification of electron density profile in the sub-ionosphere, which is based on the genetic algorithm, was developed. We verified a validity of our proposed method for the problem where an ionospheric perturbation exists 500km away from a transmitter and observation points are distributed over 1,000km X 100km, and confirmed that the method successfully works with sufficient precision., 17K06295
Apr. 2017 - Mar. 2021

Development of Detection and Monitoring Technique for Crustal Movement Preparation Process and Underground Flow by Sea-Land Integrated Electromagnetic Observation Network
Hattori Katsumi; SONODA Jun; MAEDA Takashi; TANBO Toshiya; SATO Toshinori; MIYAUCHI Takahiro
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Chiba University, Grant-in-Aid for Scientific Research (A), In this research, the followings have been coordinated and executed; 1) Construction of the integrated electromagnetic observation network in Boso area and ocean bottom electromagnetic measurements off Boso, 2) Development of signal processing methods such as signal discrimination, time series analysis, and statistical evaluation, 3) MT exploration of the Boso Peninsula to understanding the underground structure, 4) Elucidation of the physical mechanism of seismo-electromagnetic signals by rock experiments, sand box experiments, and computer simulations, 5) Investigation on correlation among mechanical, seismological, electromagnetic phenomena.
We found the statistical significance between sizable earthquake and ULF magnetic or Ionospheric anomalous changes and assessed them as precursors of the earthquake. That is, we found out the existence of precursory phenomena in earthquake preparation process and it is possible to develop the short-term earthquake forecast technology using them., 26249060
01 Apr. 2014 - 31 Mar. 2018

A study on computational electromagnetics for global electromagnetic compatibility
Ando Yoshiaki
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), In this research, simulation techniques for natural electromagnetic phenomena are developed. First, I developed a perfectly matched layer (PML) to absorb waves at boundaries of a computational domain with the shape of spherical sectors. The numerical measurements show that the developed PML has effective absorbing performance. Second, I developed an identification method of electron density profile in the D-region of the ionosphere by using the VLF/LF waveguide propagation simulation. If the identification parameters are appropriate, approximated profiles can be obtained. Third, the weighted Laguerre polynomial finite difference time domain (WLP-FDTD) method was considered as an effective simulation for electromagnetic wave propagation in the lithosphere. The WLP-FDTD method shows extremely high performance for the simulation, and is about 3000 times faster than the conventional FDTD method., 26420224
Apr. 2014 - Mar. 2018

Study of seismo-electromagnetic phenomena (lithosphere-atmosphere-ionosphere coupling)
HAYAKAWA Masashi; ANDO Yoshiaki; OHTA Kenji; HATTORI Katsumi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (B), The main results can be summarized as follows. (1)Data collection and analysis of observational data in Japan Two important physical parameters are studied extensively : (1)ULF emissions and (2)ionospheric perturbations associated with earthquakes. Event studies have been performed for the 2004 Niigata earthquake, for which we have observed clear precursory effect of ULF emissions as determined by direction finding at Nagoya and we could detect clear precursory ionospheric perturbations on the JJY-Kochi path. Another large earthquake, Indonesia Sumatra earthquake was studied ; we could identify both ULF emissions and ionospheric perturbations for this earthquake. Further, a statistical study further on the correlation between ionospheric perturbations and earthquakes has been undertaken with a good success. (2)VLF observation in Italy, Greece and Taiwan and the data analysis The VLF observations in these three countries are going good, and we have been continuing the data analysis. (3)Study of lithosphere-atmosphere-ionosphere coupling We have suggested the atmospheric gravity waves as the most likely candidate for this coupling, as evidenced from the spectral analysis of VLF amplitude fluctuation. Our extensive ground-based data have been coordinated with the French DEMETER satellite data to study further the mechanism of lithosphere-atmosphere-ionosphere coupling., 15403012
2003 - 2005