Papers - KODERA Sachiko
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SHARM: Segmented Head Anatomical Reference Models Reviewed
E. A. Rashed, M. Al-Shatouri, I. Laakso, S. Kodera, A. Hirata
Biomedical Signal Processing and Control 104 107481 2025.06
Language：English Publishing type：Research paper (scientific journal)
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Recent advances and future perspective in computational bioelectromagnetics for exposure assessments. Reviewed International coauthorship International journal
Yinliang Diao, Wout Joseph, Dragan Poljak, Luca Giaccone, Sachiko Kodera, Ilkka Laakso, Kenichi Yamazaki, Kun Li, Kensuke Sasaki, Emmeric Tanghe, Mario Cvetković, Walid El Hajj, Takashi Hikage, Fatih Kaburcuk, Gernot Schmid, Anna Šušnjara Nejašmić, Thomas Tarnaud, Vitas Anderson, Kenneth R Foster, Theodoros Samaras, Richard A Tell, Soichi Watanabe, Chung-Kwang Chou, Akimasa Hirata
Bioelectromagnetics 46 ( 3 ) e70002 2025.04
Language：English Publishing type：Research paper (scientific journal)
In the last few decades, extensive efforts have been dedicated to developing computational methods for modeling the interaction of the human body with electromagnetic fields (EMFs). These studies are crucial for the establishment of exposure limits in international standards and guidelines for human protection from EMF, as well as for advancing personalized dosimetry assessment for medical applications using EMF. To summarize the state-of-the-art knowledge in this field, the IEEE International Committee on Electromagnetic Safety (ICES) held an International Workshop on Computational Bioelectromagnetics in February 2024. This review summarizes the technical presentations and discussions from the workshop and was contributed by multiple authors, encompassing topics such as the tissue dielectric property measurement, low-frequency and radio-frequency bioelectromagnetic modeling methods, stochastic modeling in electromagnetic-thermal dosimetry, intercomparison studies, and computational uncertainties. The insights gained from this workshop will guide future research and aid in the development of more accurate and reliable exposure assessment methods.
DOI： 10.1002/bem.70002
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Single exposure to near-threshold 5G millimeter wave modifies restraint stress responses in rats Reviewed
A. Matsumoto, I. Endo, E. Ijima, A. Hirata, S. Kodera, M. Ichiba, M. Tokiya, T. Hikage, and H. Masuda
Environmental Health and Preventive Medicine 2025.04
Language：English Publishing type：Research paper (scientific journal)
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Predicting heat-related morbidity in Japan through Integrated meteorological and behavioral factors Reviewed
T. Matsuura, S. Kodera, and A. Hirata
Environmental Challenges 18 101106 2025.04
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Power absorption and temperature rise in deep learning based head models for local radiofrequency exposures Reviewed International coauthorship International journal
Sachiko Kodera, Reina Yoshida, Essam A Rashed, Yinliang Diao, Hiroyuki Takizawa, Akimasa Hirata
Physics in medicine & biology 2025.02
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：IOP publishing
Abstract
Objective: Computational uncertainty and variability of power absorption and temperature rise in humans for radiofrequency (RF) exposure is a critical factor in ensuring human protection. This aspect has been emphasized as a priority. However, accurately modeling head tissue composition and assigning tissue dielectric and thermal properties remains a challenging task. This study investigated the impact of segmentation-based versus segmentation-free models for assessing localized RF exposure. 
Approach: Two computational head models were compared: one employing traditional tissue segmentation and the other leveraging deep learning to estimate tissue dielectric and thermal properties directly from magnetic resonance images. The finite-difference time-domain method and the bioheat transfer equation was solved to assess temperature rise for local exposure. Inter-subject variability and dosimetric uncertainties were analyzed across multiple frequencies.
Main Results: The comparison between the two methods for head modeling demonstrated strong consistency, with differences in peak temperature rise of 7.6±6.4%. The segmentation-free model showed reduced inter-subject variability, particularly at higher frequencies where superficial heating dominates. The maximum relative standard deviation in the inter-subject variability of heating factor was 15.0% at 3 GHz and decreased with increasing frequencies.
Significance: This study highlights the advantages of segmentation-free deep-learning models for RF dosimetry, particularly in reducing inter-subject variability and improving computational efficiency. While the differences between the two models are relatively small compared to overall dosimetric uncertainty, segmentation-free models offer a promising approach for refining individual-specific exposure assessments. These findings contribute to improving the accuracy and consistency of human protection guidelines against RF electromagnetic field exposure.Other Link： https://iopscience.iop.org/article/10.1088/1361-6560/adb935/pdf
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高速高精度脳機能イメージングのための脳波電流源推定精度の数値的評価 Reviewed
新津 正宗，小寺 紗千子，田中 裕士，阪本 卓也，平田 晃正
電子情報通信学会論文誌C 2025.02
Authorship：Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)
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個々人の血流ばらつきを考慮した複合物理解析による知覚温度上昇推定 Invited Reviewed
新井 紀香，湯浅 明子，上原 信太郎，牛澤 一樹，大高 洋平，Chun Ren Phang，後藤 俊幸，平田 晃正，小寺 紗千子
電子情報通信学会論文誌C 2025.01
Authorship：Last author, Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)
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Estimating the perception threshold of electrostimulation and heating for radiofrequency contact current Reviewed
S. Kodera, S. Kimura, S. Uehara, A. Yuasa, K. Ushizawa, Y. Otaka, A. Hirata
IEEE Transactions on Electromagnetic Compatibility Early access 2024.11
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Assessment of whole-body-average SAR for exposure to electromagnetic fields up to 30 GHz using body model with scaled dielectric parameters Reviewed International coauthorship
Y. Diao, S. Kodera, K. Li, and A. Hirata
IEEE Transactions on Electromagnetic Compatibility 2024.11
Language：English Publishing type：Research paper (scientific journal)
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Differential impact of SARS-CoV-2 infection during different outbreak periods on incident diabetes in Japan: a matched cohort study utilizing health insurance claims Reviewed
Akiko Matsumoto, Sachiko Kodera, Tatsuya Matsuura, Yoko Takayama, Yuya Yamada, Akimasa Hirata
Environmental Health and Preventive Medicine 2024.10
Language：English Publishing type：Research paper (scientific journal)
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Electric field envelope focality in superficial brain areas with linear alignment montage in temporal interference stimulation Reviewed International coauthorship
A. Hirata, Y. Akazawa, S. Kodera, N. Otsuru, I. Laakso
Computers in Biology and Medicine 178 108697 2024.08
Language：English
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A novel multivariate time series forecasting dendritic neuron model for COVID-19 pandemic transmission tendency Reviewed International coauthorship
C. Tang, Y. Todo, S. Kodera, R. Sun, A. Shimada, and A. Hirata
Neural Networks 179 106527 2024.07
Language：English Publishing type：Research paper (scientific journal)
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Perceptional Threshold of Electrostimulation and Heating for Intermediate Contact Current Reviewed
A. Hirata, S. Kimura, S. Kodera, S. Uehara, A. Yuasa, K. Ushizawa,Y. Otaka
BioEM 2024 2024.06
Language：English Publishing type：Research paper (international conference proceedings)
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Core temperature rise for whole-body exposure in GHz band at different ambient temperature Reviewed
R. Okuda, S. Kodera, A. Hirata
EMC JAPAN/APEMC OKINAWA 2024.05
Language：English Publishing type：Research paper (international conference proceedings)
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Estimation of number of heatstroke patients with ambient temperature and solar radiation Reviewed
T. Matsuura, S. Kodera, A. Hirata
EMC JAPAN/APEMC OKINAWA 2024.05
Language：English Publishing type：Research paper (international conference proceedings)
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Evaluation of absorbed power density for complex surface Reviewed
S. Kodera, K. Kinoshita, A. Hirata
EMC JAPAN/APEMC OKINAWA 2024.05
Authorship：Lead author Language：English Publishing type：Research paper (international conference proceedings)
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28GHz人体背部ばく露による体温上昇解析 Reviewed
木下 晃太朗，増田 宏，小寺 紗千子
電子情報通信学会論文誌Cショートノート 2024.05
Authorship：Last author, Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)
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Core temperature rise for whole-body exposure in GHz band at different ambient temperature
R. Okuda, S. Kodera, A. Hirata
EMC JAPAN/APEMC OKINAWA 2024.05
Language：English Publishing type：Research paper (international conference proceedings)
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Projection of future heat-related morbidity in three metropolitan prefectures of Japan based on large ensemble simulations of climate change under 2°C global warming scenarios Reviewed
H. Ueta, S. Kodera, S. Sugimoto, A. Hirata
Environmental Research 247 118202 2024.04
Language：English Publishing type：Research paper (scientific journal)
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Compliance assessment of the spatial averaging method for magnetic field leakage from a wireless power transfer system in electric vehicles Invited Reviewed
M. Okada, K. Miwa, S. Kodera, A. Hirata
Applied Sciences 14 ( 7 ) 2672 2024.03
Language：English Publishing type：Research paper (scientific journal)
DOI： 10.3390/app14072672
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Sensitivity of electrocardiogram on electrode-pair locations for wearable devices: Computational analysis of amplitude and waveform distortion Reviewed
K. Sanjo, K. Hebiguchi, C. Tang, E. A. Rashed, S. Kodera, H. Togo, A. Hirata
Biosensors 14 ( 3 ) 153 2024.03
Language：English Publishing type：Research paper (scientific journal)
DOI： 10.3390/bios14030153
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Individual and group-level optimization of electric field in deep brain region during multichannel transcranial electrical stimulation Reviewed
H. Nishimoto, S. Kodera, N. Otsuru, and A. Hirata
Frontiers in Neuroscience 18 1332135 2024.03
Language：English Publishing type：Research paper (scientific journal)
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The thermal sensation threshold and its reliability induced by the exposure to 28 GHz millimeter-wave Reviewed
A. Yuasa, S. Uehara, K. Ushizawa, S. Kodera, N. Arai, A. Hirata, Y. Otaka
Frontiers in Neuroscience 18 1331416 2024.02
Language：English Publishing type：Research paper (scientific journal)
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High-resolution EEG source localization in personalized segmentation-free head model with multi-dipole fitting Reviewed
A. Hirata, M. Niitsu, C. R. Phang, S. Kodera, T. Kida, E. A. Rashed, M. Fukunaga, N. Sadato, and T. Wasaka
Physics in Medicine & Biology 69 ( 5 ) 055013 2024.02
Language：English Publishing type：Research paper (scientific journal)
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Spatially averaged epithelial/absorbed power density for nonplanar skin models exposed to antenna at 10–90 GHz Reviewed International coauthorship
K. Li, S. Kodera, D. Poljak, Y. Diao, K. Sasaki, S. Zhang, M. Yao, A. Kapetanovic, C. Li, T. Wu, T. Liebig, W. Simon, A. Hirata
IEEE Access 2024.01
Language：English Publishing type：Research paper (scientific journal)
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Estimating the perception threshold of electrostimulation and heating for radiofrequency contact current (in press) Reviewed
S. Kodera, S. Kimura, S. Uehara, A. Yuasa, K. Ushizawa, Y. Otaka, A. Hirata
IEEE Transactions on Electromagnetic Compatibility 2024
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Wireless power transfer systems with composite cores for magnetic field shielding with electric vehicles Reviewed International coauthorship
X. Duan, J. Lan, S. Kodera, J. Kirchner, G. Fischer, A. Hirata
IEEE Access 11 144887 - 144901 2023.12
Language：English Publishing type：Research paper (scientific journal)
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核白内障における環境温度の変化に伴う水晶体中ミトコンドリア機能について
武田 峻, 山本 直樹, 初坂 奈津子, 平松 範子, 長井 紀章, 出口 粧央里, 中澤 洋介, 高田 匠, 小寺 紗千子, 平田 晃正, 久保 江理, 佐々木 洋
金沢医科大学雑誌 48 ( 2 ) 89 - 89 2023.12
Language：Japanese Publisher：金沢医科大学医学会
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Association of nuclear cataract prevalence with UV radiation and heat load in lens of older people -five city study-
Kotaro Kinoshita, Sachiko Kodera, Natsuko Hatsusaka, Ryusuke Egawa, Hiroyuki Takizawa, Eri Kubo, Hiroshi Sasaki, Akimasa Hirata
Environmental Science and Pollution Research 30 ( 59 ) 123832 - 123842 2023.11
Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC
Epidemiological studies have reported that the frequency of nuclear cataracts (NUCs) is high among the elderly and in tropical countries. Ultraviolet (UV) irradiation and lens temperature are considered as key physical contributors, although their precise quantification is difficult. The aim of this study is to investigate the association of NUC prevalence with UV irradiation and heat load. First, we assessed the lens temperature using thermodynamic modeling considering the thermophysiological response. We then conducted a multivariate linear regression analysis for the epidemiological analysis of NUC prevalence across five cities. A strong correlation was observed between NUC prevalence and the combined effects of UV irradiation and cumulative equivalent minutes at 43 °C (CEM43°C) derived from the computed lens temperature (adjusted R2 = 0.933, p < 0.0001). Heat load significantly contributed to the prevalence at 52%, surpassing the contributions of UV irradiation (31%) and the decline in DNA repair capacity in the lens (17%). These results suggested that both UV radiation and heat load are associated with NUC, with heat load contributing more. Our findings provided important implications for future interventions, particularly in the context of global warming.
DOI： 10.1007/s11356-023-31079-2
Other Link： https://link.springer.com/article/10.1007/s11356-023-31079-2/fulltext.html
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Excessive whole-body exposure to 28 GHz quasi-millimeter wave induces thermoregulation accompanied by a change in skin blood flow proportion in rats Reviewed
E. Ijima, S. Kodera, A. Hirata, T. Hikage, A. Matsumoto, T. Ishitake, and H. Masuda
Frontiers in Public Health 11 1225896 2023.09
Language：English Publishing type：Research paper (scientific journal)
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Population-level immunity for transient suppression of COVID-19 waves in Japan from April 2021 to September 2022 Reviewed
S. Kodera, H. Ueta, T. Unemi, T. Nakata, A. Hirata
Vaccines 11 ( 9 ) 1457 2023.09
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
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Calculation of electric field induced in the human body for simultaneous exposure to spatially uniform ELF electric and magnetic fields with a phase difference Reviewed
Y. Sekiba, S. Kodera, K. Yamazaki, A. Hirata
IEEE Acccess 11 95455 - 95466 2023.09
Language：English Publishing type：Research paper (scientific journal)
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Computation of whole-body average SAR in realistic human models from 1 to 100 GHz Reviewed International coauthorship
S. Kodera, K. Taguchi, Y. Diao, T. Kashiwa, and A. Hirata
IEEE Transactions on Microwave Theory and Techniques 2023.09
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Computer-aided fast brain function mapping by transcranial magnetic stimulation
K. Hikita, K. Iijima, S. Kodera, S. Ueno, A. Hirata
URSI GASS 2023 2023.08
Language：English Publishing type：Research paper (international conference proceedings) Publisher：URSI GASS
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Optimization of electrode positions for multi-electrodes tES for deep brain stimulations
H. Nishimoto, S. Kodera, A. Hirata
URSI GASS 2023 2023.08
Language：English Publishing type：Research paper (international conference proceedings) Publisher：URSI GASS
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Characteristics of current perception produced by intermediate-frequency contact currents in healthy adults Reviewed
S. Uehara, A. Yuasa, K. Ushizawa, S. Kodera, Y. Kamimura, A. Hirata, Y. Otaka
Frontiers in Neuroscience 17 1145505 2023.04
Language：English Publishing type：Research paper (scientific journal)
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Projection of COVID-19 positive cases considering hybrid immunity: Case study in Tokyo Reviewed
Sachiko Kodera, Akito Takada, Essam A. Rashed, and Akimasa Hirata
Vaccines 11 ( 3 ) 633 2023.03
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Whole-Body Exposure System Using Horn Antennas with Dielectric Lens at 28 GHz
Sachiko Kodera, Norika Miura, Yinliang Diao, Miyako Inoue, Takashi Hikage, Kenji Taguchi, Hiroshi Masuda, Akimasa Hirata
IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology 7 ( 1 ) 65 - 72 2023.03
Publishing type：Research paper (scientific journal)
In the revised international guidelines and standard for human protection from electromagnetic fields, the permissible specific absorption rate (SAR) for whole-body exposure has been extended from 3 or 10 GHz to 300 GHz. The rationale for this revision is the extrapolation from findings of conventional radio-frequency exposure and infrared radiation. However, experiments of whole-body exposure in human subjects are limited to a few studies, which were conducted below 6 GHz. In this study, an exposure system at 28 GHz targeting a wide area of the human back was developed, which consists of two horn antennas with a dielectric lens. The effectiveness of the proposed exposure system was evaluated by computational dosimetry and experiments. The computed power absorption and measured distributions in the wave absorber and the back of the human subject were in good agreement. Under the compliance with the local exposure limits, the whole-body average SAR was 0.35 W/kg, which is comparable to the limit for whole-body exposure of 0.4 W/kg for occupational exposure in the international guidelines and standard. The developed exposure system would be useful to evaluate the thermophysiological response to whole-body exposure above 6 GHz.
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Whole-body exposure system using horn antennas with dielectric lens at 28 GHz Reviewed International coauthorship
S. Kodera, N. Miura, Y. Diao, M. Inoue, T. Hikage, K. Taguchi, H. Masuda, and A. Hirata
IEEE Journal of Electromagnetics, RF, and Microwaves in Medicine and Biology 2023.03
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
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幼若雄ラットへの5Gミリ波短時間全身ばく露に対するストレス応答の定量的評価 Reviewed
松本 明子, 遠藤 郁実, 井島 悦子, 平田 晃正, 小寺 紗千子, 市場 正良, 土器屋 美貴子, 増田 宏
日本衛生学雑誌 78 ( Suppl. ) S187 - S187 2023.03
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：(一社)日本衛生学会
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Estimation of the number of heat illness patients in eight metropolitan prefectures of Japan: Correlation with ambient temperature and computed thermophysiological responses Reviewed
A. Takada, S. Kodera, K. Suzuki, M. Nemoto, R. Egawa, H. Takizawa, and A. Hirata
Frontiers in Public Health 11 1061135 2023.02
Language：English Publishing type：Research paper (scientific journal)
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Calculated epithelial/absorbed power density for exposure from antennas at 10–90 GHz : Intercomparison study using a planar skin model Reviewed International coauthorship
K. Li, S. Kodera, D. Poljak, Dragan, Y. Diao, K. Sasaki, A. Susnjara, A. Prokop, K. Taguchi, J. Xi, S. Zhang, M. Yao, G. Sacco, M. Zhadobov, W. EI Hajj, and A. Hirata
2023.01
Language：English Publishing type：Research paper (scientific journal)
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The effects of time window averaged mobility on effective reproduction number of COVID-19 viral variants in urban cities Reviewed
S. Kodera, K. Hikita, E. A. Rashed, A. Hirata
Jounal of Urban Health 100 29 - 39 2023.01
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
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Estimation of mRNA COVID-19 vaccination effectiveness in Tokyo for Omicron variants BA.2 and BA.5 –Effect of social behavior– Reviewed
S. Kodera, Y. Niimi, E. A. Rashed, N. Yoshinaga, M. Toyoda, and A. Hirata
Vaccines 10 ( 11 ) 1820 2022.10
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
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COVID-19 forecasting using new viral variants and vaccination effectiveness models Reviewed
E. A. Rashed, S. Kodera, A. Hirata
Computers in Biology and Medicine 149 105986 2022.08
Language：English Publishing type：Research paper (scientific journal)
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Computation of absorbed power densities in high-resolution head models by considering skin thickness in quasi-millimeter and millimeter wave bands Reviewed
K. Taguchi, S. Kodera, T. Kashiwa, and A. Hirata
IEEE Journal of Electromagnetics, RF, and Microwaves in Medicine and Biology 2022.08
Language：English Publishing type：Research paper (scientific journal)
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Did the Tokyo Olympic Games enhance the transmission of COVID-19? -Interpretation with machine learning- Reviewed International coauthorship
A. Hirata, S. Kodera, Y. Diao, and E. A. Rashed
Computers in Biology and Medicine 146 105548 2022.05
Language：English Publishing type：Research paper (scientific journal)
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次世代通信システムからの人体防護のための数値的評価 Invited Reviewed
小寺紗千子, 田口健治, 佐々木謙介
電子情報通信学会論文誌C J105-C 132 - 138 2022.05
Authorship：Lead author, Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)
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Computed and measured core temperature of patients with heatstroke transported from their homes via ambulance Reviewed
Akito Takada, S. Kodera, H. Togo, M. Shimizu, H. Niwa, T. Ishikura, H. Tanaka, T. Kawahara, and A. Hirata
IEEE Acccess 10 41839 - 41851 2022.04
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Estimation of real-world vaccination effectiveness of mRNA COVID-19 vaccines against delta and omicron variants in Japan Reviewed
S. Kodera, E. A. Rashed, A. Hirata
vaccines 10 ( 3 ) 430 2022.03
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
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Power absorption and skin temperature rise from simultaneous near-field exposure at 2 and 28 GHz Reviewed International coauthorship
N. Miura, S. Kodera, Y. Diao, J. Higashiyama, Y. Suzuki, and A. Hirata
IEEE Acccess 9 152140 - 152149 2021.11
Language：English Publishing type：Research paper (scientific journal)
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Intercomparison of calculated incident power density and temperature rise for exposure from different antennas at 10–90 GHz Reviewed International coauthorship
K. Li, Y. Diao, K. Sasaki, A. Prokop, D. Poljak, V. Doric, J. Xi, S. Kodera, A. Hirata, and W. El Hajj
IEEE Acccess 9 151654 - 151666 2021.11
Language：English Publishing type：Research paper (scientific journal)
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Social implementation and intervention with estimated morbidity of heat-related illnesses from weather data: A case study from Nagoya City, Japan Reviewed
Sustainable Cities and Society 74 103203 2021.11
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Body core temperature estimation using new compartment model with vital data from wearable devices Reviewed
A. Hirata, T. Miyazawa, R. Uematsu, S. Kodera, Y. Hashimoto, K. Takagahara, Y. Higuchi, H. Togo, T. Kawahara, H. Tanaka
IEEE Acccess 9 124452 - 124462 2021.09
Language：English Publishing type：Research paper (scientific journal)
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Effect of incidence angle on the incident power density definition to correlate skin temperature rise for millimeter wave exposures Reviewed International coauthorship
Y. Diao, K. Li, K. Sasaki, S. Kodera, I. Laakso, W. E. Hajj, and A. Hirata
IEEE Transactions on Electromagnetic Compatibility 63 ( 5 ) 1709 - 1716 2021.08
Language：English Publishing type：Research paper (scientific journal)
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Influence of population density, temperature, and absolute humidity on spread and decay durations of COVID-19: A comparative study of scenarios in China, England, Germany, and Japan Reviewed International coauthorship
Y. Diao, S. Kodera, D. Anzai, J. Gomez-Tames, E. A. Rashed, and A. Hirata
One Health 12 100203 2021.06
Language：English Publishing type：Research paper (scientific journal)
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Human exposure to radiofrequency energy above 6 GHz: review of computational dosimetry studies Invited Reviewed
A. Hirata, S. Kodera, K. Sasaki, J. Gomez-Tames, I. Laakso, A. Wood, S. Watanabe, K. R. Foster
Physics in Medicine & Biology 66 08TR01 2021.04
Language：English Publishing type：Research paper (scientific journal)
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Knowledge discovery from emergency ambulance dispatch during COVID-19: A case study of Nagoya City, Japan Reviewed International coauthorship
E. A. Rashed, S. Kodera, H. Shirakami, R. Kawaguchi, K. Watanabe, and A. Hirata
Jounal of Biomedical Informatics 117 103743 - 103743 2021.03
Language：English Publishing type：Research paper (scientific journal)
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Effect of a lens protein in low-temperature culture of novel immortalized human lens epithelial cells (iHLEC-NY2) Reviewed
N. Yamamoto, S. Takeda, N. Hatsusaka, N. Hiramatsu, N. Nagai, S. Deguchi, Y. Nakazawa, T. Takata, S. Kodera, A. Hirata, E. Kubo, and H. Sasaki
cells 9 2970 2020.12
Language：English Publishing type：Research paper (scientific journal)
DOI： 10.3390/cells9122670
DOI： 10.3390/cells9122670
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Evaluation of SAR and temperature rise in human hand due to contact current from 100 kHz to 100 MHz Reviewed International coauthorship
T. Murakawa, Y. Diao, E. A. Rashed, S. Kodera, Y. Tanaka, Y. Kamimura, S. Kitamura, S. Uehara, Y. Otaka, A. Hirata
IEEE Acccess 200995 - 201004 2020.11
Language：English Publishing type：Research paper (scientific journal)
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A. Hirata, S. Kodera Invited Reviewed
Difference of ICNIRP guidelines and IEEE C95. 1 standard for human protection from radio-frequency exposures
2020 International Symposium on Electromagnetic Compatibility-EMC EUROPE 2020.09
Language：English Publishing type：Research paper (international conference proceedings)
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Correlation between estimated thermoregulatory responses and pacing in athletes during marathon Reviewed International coauthorship
S. Kodera, T. Kamiya, T. Miyazawa, A. Hirata
IEEE Acccess 173079 - 173091 2020.09
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Model-based approach for analyzing prevalence of nuclear cataracts in elderly residents Reviewed International coauthorship
S. Kodera, A. Hirata, F. Miura, E. A. Rashed, N. Hatsusaka, N. Yamamoto, E. Kubo, and H. Sasaki
Computers in Biology and Medicine 126 104009 2020.09
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
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Correlation between COVID-19 morbidity and mortality rates in Japan and local population density, temperature, and absolute humidity Reviewed
S. Kodera, E. A. Rashed, and A. Hirata
International Journal of Environmental Research and Public Health 17 5477 2020.07
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
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Influence of absolute humidity and population density on COVID-19 spread and decay durations: Multi-prefecture study in Japan Reviewed
E. A. Rashed, S. Kodera, J. Gomez-Tames, and A. Hirata
International Journal of Environmental Research and Public Health 17 5354 2020.07
Language：English Publishing type：Research paper (scientific journal)
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Estimation of time-course core temperature and water loss in realistic adult and child models with urban micrometeorology prediction Reviewed
T. Kamiya, R. Onishi, S. Kodera, and A. Hirata
International Journal of Environmental Research and Public Health 16 5097 2019.12
Language：English Publishing type：Research paper (scientific journal)
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Estimation of heat-related morbidity from weather data: A computational study in three prefectures of Japan over 2013–2018 Reviewed
S. Kodera, T. Nishimura, E. Rashed, K. Hasegawa, I. Takeuchi, R. Egawa, H. Sasaki, and A. Hirata
Environment International 130 104907 2019.09
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
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Permissible SA and Radiant Exposure for Brief Exposure in GHz Region
Sachiko Kodera, Akimasa Hirata
EMC Europe 2019 - 2019 International Symposium on Electromagnetic Compatibility 1020 - 1024 2019.09
Language：English Publishing type：Research paper (international conference proceedings) Publisher：Institute of Electrical and Electronics Engineers Inc.
The specific absorption rate (SAR) averaged over 10 g of tissue is used as a physical quantity to prevent local temperature elevation in the international guidelines for constant exposure to radio-frequency electromagnetic fields. The averaging time of SAR is set to 6 min for local exposure. The ICNIRP public consultation document introduced a new physical quantity, absorbed power density (APD), as the basic restriction above 6 GHz. In addition, the limit for the specific absorption (SA) and absorbed energy density (AED) were set to avoid heating for brief exposures (shorter than the averaging time of 6 min). If all the energy for the averaging time of 6 min for continuous wave are concentrated into short duration and multiple pulse exposures, the local temperature elevation for the pulse(s) may exceeds that of exposure at almost constant exposure although it satisfies the limit for the SAR/APD. The purpose of this study is to determine how best to set the metric in order to limit temperature rise from brief exposures. We first confirmed that the peak temperature elevation for brief pulse exceeds the steady-state temperature for continuous exposure. We then proposed the limit energy density from the regression curve depending on the exposure duration of brief-pulse(s). The time course of temperature elevation in the multi-layer cube model was computed for typical scenarios of multiple pulses exposures. The SA and AED based on the regression curve can be used as a metric to prevent excess temperature elevation for different brief exposure scenario.
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5G communications systems and radiofrequency exposure limits Invited International coauthorship
K. R. Foster, S. Kodera, and A. Hirata
IEEE Future Networks Tech Focus 3 ( 2 ) 2019.09
Language：English Publishing type：Research paper (scientific journal)
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Different thermoregulatory responses of people from tropical and temperate zones: A computational study Reviewed
T. Kamiya, S. Kodera, K. Hasegawa, R. Egawa, H. Sasaki, and A. Hirata
Building and Environment 159 106152 2019.07
Language：English Publishing type：Research paper (scientific journal)
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Setting exposure guidelines and product safety standards for radio-frequency exposure at frequencies above 6 GHz: brief review Invited Reviewed
A. Hirata, D. Funahashi, and S. Kodera
Annals of Telecommunications 74 17 - 24 2019.01
Language：English Publishing type：Research paper (scientific journal)
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Area-averaged transmitted power density at skin surface as metric to estimate surface temperature elevation Reviewed International coauthorship
D. Funahashi, A. Hirata, S. Kodera, and K. R. Foster
IEEE Acccess 6 77665 - 77674 2018.11
Language：English Publishing type：Research paper (scientific journal)
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Temperature rise for brief radio-frequency exposure below 6 GHz Reviewed International coauthorship
S. Kodera, A. Hirata, D. Funahashi, S. Watanabe, K. Jokela, and R. J. Croft
IEEE Acccess 6 65737 - 65746 2018.10
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
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Comparison of thermal response for RF exposure in human and rat models Reviewed
S. Kodera and A. Hirata
International Journal of Environmental Research and Public Health 15 ( 10 ) 2320 2018.10
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Risk evaluation of heat stroke with multiphysics computation and its application Invited Reviewed International coauthorship
A. Hirata, K. Hasegawa, S. Kodera, I. Laakso, R. Egawa, Y. Horie, N. Yazaki, K. Taguchi, T. Kashiwa
The Institute of Electtrical Enginieers of Japan 138 ( 6 ) 288 - 294 2018.06
Language：Japanese Publishing type：Research paper (scientific journal)
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Risk management of heatstroke based on fast computation of temperature and water loss using weather data for exposure to ambient heat and solar radiation Reviewed International coauthorship
K. Kojima, A. Hirata, K. Hasegawa, S. Kodera, I. Laakso, D. Sasaki, T. Yamashita, R. Egawa, Y. Horie, N. Yazaki, S. Kowata, K. Taguchi, and T, Kashiwa
IEEE Acccess 6 3774 - 3785 2018.01
Language：English Publishing type：Research paper (scientific journal)
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Temperature elevation in the human brain and skin with thermoregulation during exposure to RF energy Reviewed International coauthorship
S. Kodera, J. Gomez-Tames, and A. Hirata
BioMedical Engineering OnLine 17 ( 1 ) 1 - 17 2018.01
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
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太陽光および暑熱同時ばく露に対する熱中症リスク評価シミュレータの開発 Reviewed
西尾渉, 小寺紗千子, 平田晃正, 佐々木大輔, 山下毅, 江川隆輔, 小林広明, 曽根秀昭
電子情報通信学会論文誌C J100-C ( 5 ) 208 - 216 2017.05
Language：Japanese Publishing type：Research paper (scientific journal)
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ラット脳局所ばく露マルチフィジクス解析の高精度化 Reviewed
小寺紗千子, 森本涼太, 平田晃正, 増田宏, 有馬卓司, 渡辺聡一
電子情報通信学会論文誌C J100-C ( 5 ) 200 - 207 2017.05
Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)
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Accurate Multi-physics Analysis of Temperature Elevation in Rat Brain for Localized Microwave Exposure Reviewed
S. Kodera, R. Morimoto, A. Hirata, H. Masuda, T. Arima, S. Watanabe
J100-C ( 5 ) 200 - 207 2017.05
Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)
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Multiphysics and thermal response models to improve accuracy of local temperature estimation in rat cortex under microwave exposure Reviewed
S. Kodera, J. Gomez-Tames, A. Hirata, H. Masuda, T. Arima, and S. Watanabe
International Journal of Environmental Research and Public Health 14 ( 4 ) 358 2017.03
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Dominant factors for influencing whole-body average SAR due to far-field exposure in whole-body resonance frequency and GHz regions Reviewed
A. Hirata, S. Kodera, J. Wang, and O. Fujiwara
Bioelectromagnetics 28 484 - 487 2007.09
Language：English Publishing type：Research paper (scientific journal)
DOI： 10.1002/bem.20335
DOI： 10.1002/bem.20335
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FDTD calculation of whole-body average SAR in adult and child models for frequencies from 30 MHz to 3 GHz Invited Reviewed
J. Wang, O. Fujiwara, S. Kodera, and S. Watanabe
Physics in Medicine & Biology 51 ( 17 ) 4119 - 4128 2006.09
Language：English Publishing type：Research paper (scientific journal)
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