記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/MIPRO.2016.7522174

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：HINDAWI LTD  

Cortical dipole imaging has been developed to visualize brain electrical activity in high spatial resolution. It is necessary to solve an inverse problem to estimate the cortical dipole distribution from the scalp potentials. In the present study, the accuracy of cortical dipole imaging was improved by focusing on filtering property of the spatial inverse filter. We proposed an inverse filter that optimizes filtering property using a sigmoid function. The ability of the proposed method was compared with the traditional inverse techniques, such as Tikhonov regularization, truncated singular value decomposition (TSVD), and truncated total least squares (TTLS), in a computer simulation. The proposed method was applied to human experimental data of visual evoked potentials. As a result, the estimation accuracy was improved and the localized dipole distribution was obtained with less noise.

DOI： 10.1155/2016/8404565

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：HINDAWI LTD  

Cortical dipole imaging has been developed to visualize brain electrical activity in high spatial resolution. It is necessary to solve an inverse problem to estimate the cortical dipole distribution from the scalp potentials. In the present study, the accuracy of cortical dipole imaging was improved by focusing on filtering property of the spatial inverse filter. We proposed an inverse filter that optimizes filtering property using a sigmoid function. The ability of the proposed method was compared with the traditional inverse techniques, such as Tikhonov regularization, truncated singular value decomposition (TSVD), and truncated total least squares (TTLS), in a computer simulation. The proposed method was applied to human experimental data of visual evoked potentials. As a result, the estimation accuracy was improved and the localized dipole distribution was obtained with less noise.

DOI： 10.1155/2016/8404565

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

In the existing walking support system, the range of detection is limited, and it is very difficult to detect obstacles such as a step or a hollow. Therefore, we aim at the development of a new walking support system for a visually-impaired person detecting neighboring obstacles by making use of a smartphone which is a high-performance portable information terminal. In this study, we have developed a walking support system combining the orientation sensor of the smartphone and a small distance sensor at the first stage. When we investigated its precision in detecting an obstacle, it was found that the system could detect obstacles which disturbed the walking of a visually-impaired person such as a step and a wall. We will find an appropriate key to detection to improve the detection precision of the system and make further improvements in the system by trial experiments in the future.

DOI： 10.1109/EMBC.2015.7319929

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.17654/FJECMar2015-053-069

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER SCIENCE BV  

To provide speech prostheses for individuals with severe communication impairments, we investigated a classification method for brain computer interfaces (BCIs) using silent speech. Event-related potentials (ERPs) were recorded using scalp electrodes when five subjects imagined the vocalization of Japanese vowels, /a/, /i/, /u/, /e/, and /o/ in order and in random order, while the subjects remained silent and immobilized.
For actualization, we tried to apply relevance vector machine (RVM) and RVM with Gaussian kernel (RVM-G) instead of support vector machine with Gaussian kernel (SVM-G) to reduce the calculation cost in the use of 19 channels, common special patterns (CSPs) filtering, and adaptive collection (AC). Results show that using RVM-G instead of SVM-G reduced the ratio of the number of efficient vectors to the number of training data from 97% to 55%. At this time, the averaged classification accuracies (CAs) using SVM-G and RVM-G were, respectively, 77% and 79%, showing no degradation. However, the calculation cost was more than that using SVM-G because RVM-G necessitates high calculation costs for optimization. Furthermore, results show that CAs using RVM-G were weaker than SVM-G when the training data were few. Additionally, results showed that nonlinear classification was necessary for silent speech classification.
This paper serves as a beginning of feasibility study for speech prostheses using an imagined voice. Although classification for silent speech presents great potential, many feasibility problems remain. (C) 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.asoc.2013.10.023

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

The spatial resolution of scalp potential mapping is limited because of low conductivity of a skull. Cortical dipole layer imaging has been proposed as a method to visualize brain electrical activity with high spatial resolution. According to this method, about 100 electrodes were required to measure whole brain electrical activity. In the present study, we investigated simplified cortical dipole imaging with a small number of electrodes. The density of electrodes and the spatial resolution are in a trade-off relation. Thus, the number of electrodes was reduced by limiting the visualization region of interest, without lowering the density of electrodes. Moreover, independent component analysis was applied to the multiple signal sources to extract an attention signal from the other signals and noise. In simulation, even if the number of electrodes was reduced to 25, the obtained results were almost equivalent to the case with whole brain electrodes. The proposed method was applied to human experimental data of movement-related potential. We confirmed that the proposed method provided high resolution cortical dipole imaging with localized distribution.

DOI： 10.1109/EMBC.2014.6944731

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.11239/jsmbe.51.U-3

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.11239/jsmbe.51.U-2

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本生体工学会  

DOI： 10.11239/jsmbe.51.24

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その他リンク： http://search.jamas.or.jp/link/ui/2013308578

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

Cortical dipole imaging has been proposed as a method to visualize electroencephalogram in high spatial resolution. We investigated the inverse technique of cortical dipole imaging using a truncated total least squares (TTLS). The TTLS is a regularization technique to reduce the influence from both the measurement noise and the transfer matrix error caused by the head model distortion. The estimation of the regularization parameter was also investigated based on L-curve. The computer simulation suggested that the estimation accuracy was improved by the TTLS compared with Tikhonov regularization. The proposed method was applied to human experimental data of visual evoked potentials. We confirmed the TTLS provided the high spatial resolution of cortical dipole imaging.

DOI： 10.1109/EMBC.2013.6610772

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

To provide speech prostheses for individuals with severe communication impairments, we investigated a classification method for brain computer interfaces (BCIs) using silent speech. Event-related potentials (ERPs) obtained when four subjects imagined the vocalization of Japanese vowels, /a/, lit, /u/, /e/, and /o/ in order and in random order while the subjects remained silent and immobilized were recorded using Ill scalp electrodes and 3 reference electrodes. Regarding detection of the imagined voice, some problems occurred by which the related brain geometries and suitable electrodes for classifications differed between subjects. To overcome these problems, we used an adaptive collection that divided ERP data into small elements, performed evaluation relative to the elements, and selected better elements for classification. In earlier reports of studies using the common spatial patterns (CSPs) filter and support vector machines (SI/Ms), the classification accuracies (CAs) were 56-72% for the pairwise classification /a/ vs. /u/ in the case of 63 channel EEG measurement In this study, the CA was improved to 73-92% using the adaptive collection. According to the CA, 19 channel measurements were worse than 111 channel measurements, but 63 channel measurements were slightly worse that 111 channel measurements. Using 63 channel measurements, 73% of CA was achieved for all pairwise combinations of the five vowels. The average of the CAs was 85%. These results show that the proposed method exhibited great potential for use in classification of imagined voice for a speech prosthesis controller.

DOI： 10.1109/CIRAT.2013.6613816

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Institute of Electrical Engineers of Japan  

In clinical situations, the objective evaluation of somatic sensations is expected without a patient's subjective opinions to reduce social problems such as those related to lawsuits for nerve injuries or malingering. In this study, the somatosensory evoked potential (SEP) using the mechanical stimulations of the tactile sensation was measured and analyzed in spatiotemporal domains. The cortical potential mapping projected onto the realistic-shaped model was estimated to improve the spatial resolution of the SEP maps by application of cortical dipole layer imaging. The experimentally obtained results suggest that the spatiotemporal distributions of the SEPs reflect the differences for positions, strengths, and patterns of somatosensory stimulations. © 2013 The Institute of Electrical Engineers of Japan.

DOI： 10.1541/ieejeiss.133.169

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1541/ieejeiss.132.1798

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

The objective evaluation of somatic sensations is expected without a patient's subjective opinions to reduce social problems such as those related to lawsuits for nerve injuries or malingering. In this study, the somatosensory evoked potential (SEP) using the mechanical stimulations of the tactile sensation was measured and analyzed in spatiotemporal domains. The cortical potential mapping projected onto the realistic-shaped model was estimated to improve the spatial resolution of the SEP maps by application of cortical dipole layer imaging. The experimentally obtained results suggest that the spatiotemporal distributions of the SEPs reflect the differences for positions, strengths, and patterns of somatosensory stimulations.

DOI： 10.1109/EMBC.2012.6347024

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Electrical Engineers of Japan  

Cortical dipole imaging is one of the spatial enhancement techniques from the scalp electroencephalogram. We investigated the dipole imaging for multiple signal sources under time-varying non-uniform noise conditions. The effects of incorporating statistical information of noise into the spatiotemporal inverse filter were examined by computer simulations and experimental studies in three sphere volume conductor model. The parametric projection filter that incorporated with noise covariance was applied to the inverse problem of EEG measurements. The noise covariance matrix was estimated by applying independent component analysis to the scalp potentials. The spatial filter was expanded to apply to the time-varying non-uniform noise conditions such as eye blink artifact. Moreover, multiple dipole distributions were introduced to extract and to visualize individual signal sources. The proposed imaging technique was applied to human experimental data of visual evoked potentials. We obtained reasonable results that coincide to physiological knowledge. © 2011 The Institute of Electrical Engineers of Japan.

DOI： 10.1541/ieejeiss.131.1958

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

Cortical dipole imaging is one of the spatial enhancement techniques from the scalp electroencephalogram. We investigated the cortical dipole imaging for multiple signal sources under time-varying non-uniform noise conditions. The effects of incorporating statistical information of noise into the spatiotemporal inverse filter were examined in three sphere volume conductor model. The parametric projection filter that incorporated with noise covariance was applied to the inverse problem of EEG measurements. The noise covariance matrix was estimated by applying independent component analysis to the scalp potentials. The spatial filter was expanded to apply to the time-varying non-uniform noise conditions such as eye blink artifact. Moreover, multiple dipole distributions were introduced to extract individual signal sources. The proposed imaging technique was applied to human experimental data of visual evoked potentials. © 2011 IEEE.

DOI： 10.1109/NFSI.2011.5936813

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY  

Equivalent cortical dipole layer imaging is proposed for high-resolution electroencephalogram (EEG) visualization. Equivalent dipole layer distribution parallel to the brain surface has been used in previous head models. In the present study, the additional dipole distribution on the median plane is introduced to identify the three-dimensional (3D) position and orientation of dipole sources. The parametric Wiener filter (PWF) using statistical signal and noise information was applied to solve an inverse problem of cortical dipole imaging. Simulations were performed in an inhomogeneous, concentric, three-sphere volume conductor head model under various signal conditions. Cortical dipole imaging provided localized brain electrical activity with better spatial resolution compared to the scalp potential map. These simulation results suggested that the depth and orientation of individual dipole sources could be observed by mapping on both spherical and median planes. We applied the proposed imaging technique to human experimental data of the visual evoked potential (VEP) and obtained reasonable results that coincide with physiological knowledge. (C) 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

DOI： 10.1002/tee.20619

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

In clinical situations, the objective evaluation of somatic sensations is expected without a patient's subjective opinions to reduce social problems such as those related to lawsuits for nerve injuries and malingering. In this study, the somatosensory evoked potential (SEP) using the mechanical stimulations of the tactile sensation was measured and analyzed in spatiotemporal domains. The spatial resolution of SEP maps was improved by application of cortical dipole layer imaging. The experimentally obtained results suggest that the spatiotemporal distributions of the SEPs reflect the differences for positions, strengths, and patterns of somatosensory stimulations.

DOI： 10.1109/IEMBS.2011.6091775

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

We investigated suitable spatial inverse filters for cortical dipole imaging from the scalp electroencephalogram (EEG). The effects of incorporating statistical information of signal and noise into inverse procedures were examined by computer simulations and experimental studies. The parametric projection filter (PPF) and parametric Wiener filter (PWF) were applied to an inhomogeneous three-sphere volume conductor head model. The noise covariance matrix was estimated by applying independent component analysis (ICA) to scalp potentials. The present simulation results suggest that the PPF and the PWF provided excellent performance when the noise covariance was estimated from the differential noise between EEG and the separated signal using ICA and the signal covariance was estimated from the separated signal. Moreover, the spatial resolution of the cortical dipole imaging was improved while the influence of noise was suppressed by including the differential noise at the instant of the imaging and by adjusting the duration of noise sample according to the signal to noise ratio. We applied the proposed imaging technique to human experimental data of visual evoked potential and obtained reasonable results that coincide to physiological knowledge.

DOI： 10.1587/transinf.E93.D.2626

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

We have investigated the suitable spatial filters for inverse estimation of cortical dipole imaging from the scalp electroencephalogram. The effects of incorporating statistical information of noise into inverse procedures were examined by computer simulations and experimental studies. The parametric projection filter (PPF) was applied to an inhomogeneous three-sphere volume conductor head model. The noise covariance matrix was estimated by applying independent component analysis (ICA) to the scalp potentials. Moreover, the sampling method of the noise information was examined for calculating the noise covariance matrix. The simulation results suggest that the spatial resolution was improved while the effect of noise was suppressed by including the separated noise at the time instant of imaging and by adjusting the number of samples according to the signal to noise ratio.

DOI： 10.1109/IEMBS.2009.5334965

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1541/ieejeiss.129.1792

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

The purpose of this study is to support communication of individuals with motor paralysis having difficulty verbally communicating due to illnesses such as Guillain-Barre Syndrome or brain-stem infarction. We have developed and describe a pointing device controlled by DC-coupled electrooculograms (EOGs). The visual angle of the subject is estimated from the amplitude of vertical and horizontal EOGs for determining the two-dimensional pointing position on a PC screen in real time. The eye blinking artifact is reduced using a median filter. Electrode displacement is corrected by considering the potential gradient. Moreover, the position error caused by drift phenomenon is adjusted using head movement based on the vestibule-ocular reflex. The accuracy and operating speed of the proposed method were evaluated among a group of human subjects.

DOI： 10.1109/IEMBS.2009.5334617

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

Suitable spatial filters were explored for inverse estimation of cortical dipole imaging from a scalp electroencephalogram. Computer simulations were used to examine the effects of incorporating statistical information of signal and noise into inverse procedures. Actually, the parametric projection filter (PPF) and parametric Wiener filter (PWF) were applied to an inhomogeneous three-sphere head model. The signal and noise covariance matrices were estimated by applying independent component analysis (ICA) to the scalp potentials. The simulation results described herein suggest that the PPF using differential noise between EEG and separated signal were equivalent to those obtained using the method with actual noise. Moreover, the PWF using separated signals has better performance than traditional inverse techniques.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：電子情報通信学会  

高齢社会では視覚に障害を伴う人の増加が予想され，視覚障害者の生活の質（QOL）を向上させる支援技術を開発することはより重要になる．屋外での歩行支援，屋内での読書支援は特に重要な技術である．本論文では，高齢者や視覚障害者の読書支援を目的として，注視により拡大読書器の動作を制御する支援システムを試作した．拡大読書器の表示を制御する情報を得るため，まず視力と注視特性の関係を明らかにする実験を晴眼者で実施した．その結果，注視点の揺らぎや瞬目の回数が視力と関係をもつことが示唆された．そこで注視点揺らぎと瞬目を制御情報とする注視点制御型拡大読書器を試作した．試作した支援システムは少なくとも白内障の視覚障害者に有効であることが評価実験により示唆された.

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その他リンク： http://hdl.handle.net/10191/25910

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：SPRINGER-VERLAG BERLIN  

A number of efforts have been made in the development of high-resolution EEG techniques, which attempt to map spatially distributed brain electrical activity with substantially improved spatial resolution. The objective of this study is to explore suitable spatial filters for inverse estimation of cortical potential imaging from the scalp electroencephalogram. The effects of incorporating statistically signal and noise information into inverse procedures were examined by computer simulations and experimental study. The parametric Weiner filter (PWF) with signal and noise covariance was applied to an inhomogeneous head model under various signal and noise conditions. The present simulation results suggest that, the PWF provides better cortical imaging results than the Tikhonov regularization under the condition of moderate and high correlation between signal and noise distributions. The proposed methods were applied to self-paced movement-related potentials (MRPs). The cortical potential maps estimated by means of PWF were well-localized in the premotor cortex, which is consistent with the hand motor representation.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

We have developed new estimation method for equivalent dipole sources inside of the brain. We have solved an inverse problem that estimated an equivalent dipole-layer distribution from the scalp electroencephalogram by a spatio-temporal inverse filters. In the present study, we estimated the position and moment of equivalent dipole sources from dipole layer distributions. Moreover, we separated each dipole layer distribution using independent component analysis to identify the number, position, and moment of several dipole sources. The performance of the proposed estimation method was evaluated by computer simulation and human experimental studies in an inhomogeneous three-concentric sphere head model. The present simulation results indicated that the equivalent dipole sources were accurately estimated by our methods. We also applied the proposed method to human experimental data of movement-related potentials.

DOI： 10.1109/NFSI-ICFBI.2007.4387681

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SCHATTAUER GMBH-VERLAG MEDIZIN NATURWISSENSCHAFTEN  

Objective: The objective of this study is to explore suitable spatial filters for inverse estimation of cortical equivalent dipole layer imaging from the scalp electroencephalogram. We utilize cortical dipole source imaging to locate the possible generators of scalp-measured movement-related potentials (MRPs) in human.
Methods: The effects of incorporating signal and noise covariance into inverse procedures were examined by computer simulations and experimental study. The parametric projection filter (PPF) and parametric Weiner filter (PWF) were applied to an inhomogeneous three-sphere head model under various noise conditions.
Results: The present simulation results suggest that the PWF incorporating signal information provides better cortical dipole layer imaging results than the PPF and Tikhonov regularization under the condition of moderate and high correlation between signal and noise distributions. On the other hand, the PPF has better performance than other inverse filters under the condition of low correlation between signal and noise distributions. The proposed methods were applied to self-paced MRPs in order to identify the anatomic substrate locations of neural generators. The dipole layer distributions estimated by means of PPF are well-localized as compared with blurred scalp potential maps and dipole layer distribution estimated by Tikhonov regularization. The proposed methods demonstrated that the contralateral premotor cortex was preponderantly activated in relation to movement performance.
Conclusions: In cortical dipole source imaging, the PWF has better performance especially when the correlation between the signal and noise is high. The proposed inverse method was applicable to human experiments of MRPs if the signal and noise covariances were obtained.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

A horizontal and vertical dipole layer model was developed for three dimensional dipole layer imaging of brain electrical activity. Horizontal dipole layer being parallel to the brain surface has been used in previous head models. In the present study, the dipole layer distribution in the sagittal plane was also estimated from the scalp electroencephalogram. The parametric projection filter was applied to an inverse problem in a homogeneous plane head model under various signal conditions. The present simulation results suggest that the depth information of dipole sources could be observed by our method.

DOI： 10.1109/CNE.2007.369651

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

A communication support interface controlled by eye movements and voluntary eye blink has been developed for disabled individuals with motor paralysis who cannot speak. Horizontal and vertical electro-oculograms were measured using two surface electrodes attached above and beside the dominant eye and referring to an earlobe electrode and amplified with AC-coupling in order to reduce the unnecessary drift. Four directional cursor movements -up, down, right, and left- and one selected operation were realized by logically combining the two detected channel signals based on threshold settings specific to the individual. Letter input experiments were conducted on a virtual screen keyboard. The method's usability was enhanced by minimizing the number of electrodes and applying training to both the subject and. the device. As a result, an accuracy of 90.1 +/- 3.6% and a processing speed of 7.7 +/- 1.9 letters/min. were obtained using our method.

DOI： 10.1093/ietisy/e89-d.6.1790

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本ハイパーサーミア学会  

Many heat applicators for hyperthermia have been developed ; however, in treatment of noninvasive cancer they can heat only the body surface. At present, it is difficult to selectively heat deep-seated tumors. It is desirable to develop an applicator with the potential for heating a limited region, but achieving this objective is impossible with present technology. Therefore, our goal is to develop an applicator that can uniformly heat to deep regions of the human body. In this paper, we describe fundamental heating characteristics of an RF hyperthermic system using a rectangular resonant cavity applicator for deep-seated tumors. First, electromagnetic and heat-transfer equations were solved to investigate fundamental heating characteristics of the resonant cavity applicator. In the experiments, a torso-shaped dielectric phantom, which has electrical constants close to human muscle, was used. In comparisons of the measured and calculated results, the tendencies of both heat distributions were in accordance. These results indicated the possibility of heating deep regions ; thus, this applicator has the potential to heat deep-seated tumors.多くの癌温熱治療用加温装置が開発されている. しかしながら,非侵襲な癌温熱治療用加温装置は,人体表面近傍のみの加温が可能である. 現状では,RF波を用いて深部に位置する癌を選択的に加温することは不可能である. 局部加温の可能性を持つ装置を開発することが望ましいが,この目標を達成することは,現状の技術では不可能である. それゆえ,我々は,人体深部までを一様に加温する装置を開発することを目標とした. この論文では,立体空洞共振器をもしいた深部癌温熱治療用RFシステムの基礎的な加温特性について述べる. 初めに,基本加温特性を調べるためにMaxwellの方程式と熱伝導―熱伝達方程式を解いた. 次に, 人体筋肉の電気特性を模した誘電体ファントムを使用し,加温実験を行った. 実験結果と計算結果を比較したところ,深部加温できる傾向は一致した. すなわち,深部癌温熱治療用加温装置としての可能性を持つことが分かった.

DOI： 10.3191/thermalmedicine.22.1

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

Suitable spatial filters were explored for inverse estimation of cortical potential imaging from the scalp electroencephalogram. The effects of incorporating signal and noise covariance into inverse procedures were examined by computer simulations and experimental study. The parametric Wiener filter (PWF) was applied to an inhomogeneous three-sphere head model under various signal and noise conditions. We also examined estimation methods for the signal covariance in PWF. The present simulation results suggest that the PWF with modified matrix transformation method has better performance. The proposed methods were applied to self-paced movement-related potentials in order to identify the anatomic substrate locations of neural generators in realistic-shaped head model. The proposed methods demonstrated that the contralateral premotor cortex was preponderantly activated in relation to movement performance.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

A communication support interface controlled by eye movements and voluntary eye blink has been developed for disabled individuals with motor paralysis who cannot speak. Horizontal and vertical electro-oculograms were measured using two electrodes attached above and beside the dominant eye and referring to an earlobe electrode and amplified with AC-coupling in order to reduce the unnecessary drift. Eight directional cursor movements and one selected operation were realized by logically combining the two detected channel signals based on threshold setting specific to the individuals. As experimental results using a projected screen keyboard, processing speed was improved to 12.1 letters/min. while the accuracy was 90.4%.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

A smart video magnifier for the people with visual disabilities is now being developed to assist their stress-free reading. In a video magnifier, the users watch the monitor screen that is displaying the book page to be read. Eye movement is needed for reading a book. The difficulty of character recognition that is dependent on the environmental conditions is reflected to the eye movement. Accordingly, information on the visibility of the user is extracted as physiological signals accompanied by the gazing motion. These signals are basically used to control the video magnifier. The advantages and usefulness of the adaptive-type video magnifier are discussed in this paper.

DOI： 10.1109/IEMBS.2006.259900

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

A communication support interface controlled by eye movements and voluntary eye blink has been developed for disabled individuals with motor paralysis who cannot speak. Horizontal and vertical electro-oculograms were measured using two electrodes attached above and beside the dominant eye and referring to an earlobe electrode and amplified with AC-coupling in order to reduce the unnecessary drift. Eight directional cursor movements and one selected operation were realized by logically combining the two detected channel signals based on threshold setting specific to the individuals. As experimental results using a projected screen keyboard, processing speed was improved to 12.1 letters/min. while the accuracy was 90.4%.

DOI： 10.1109/IEMBS.2006.259914

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER-VERLAG BERLIN  

A communication support interface controlled by eye movements and voluntary eye blink has been developed for disabled individuals with motor paralysis who cannot speak. Horizontal and vertical electro-oculograms were measured using two surface electrodes attached above and beside the dominant eye and referring to an earlobe electrode and amplified with AC-coupling in order to reduce the unnecessary drift. Four directional cursor movements -up, down, right, and left- and one selected operation were realized by logically combining the two detected channel signals based on threshold settings specific to the individual. Letter input experiments were conducted on a virtual screen keyboard. As a result, operatablility, accuracy, and processing speed were improved using our method.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SCRIPTA TECHNICA-JOHN WILEY & SONS  

One of the methods of generating physical random numbers is the use of electrical signals. Previously, when random numbers have been generated from electrical signals, a threshold value has been imposed on the signal level and "0" and "1" have been assigned depending on whether this threshold value was exceeded. In the present paper, the lowest bit of an A-D converter is used so as to demonstrate that high-speed generation of random numbers, which is not achievable by the conventional method, is now possible. Further, it is demonstrated that random numbers can be generated by fluctuations of an oscillator instead by a special noise generator. (c) 2006 Wiley Periodicals, Inc.

DOI： 10.1002/ecjc.20215

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER-VERLAG BERLIN  

A communication support interface controlled by eye movements and voluntary eye blink has been developed for disabled individuals with motor paralysis who cannot speak. Horizontal and vertical electro-oculograms were measured using two surface electrodes attached above and beside the dominant eye and referring to an earlobe electrode and amplified with AC-coupling in order to reduce the unnecessary drift. Four directional cursor movements -up, down, right, and left- and one selected operation were realized by logically combining the two detected channel signals based on threshold settings specific to the individual. Letter input experiments were conducted on a virtual screen keyboard. As a result, operatablility, accuracy, and processing speed were improved using our method.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

We explored suitable estimation method for equivalent dipole sources in the brain. In a previous study, we solved an inverse problem that estimated an equivalent dipole-layer distribution from the scalp electroencephalogram by a spatio-temporal inverse filters constructed with parametric projection filter. In the present study, we estimated equivalent dipole sources from dipole layer distributions. Moreover, to identify the number, position, and moment of equivalent dipole sources, we separated each dipole layer distribution using independent component analysis (ICA). The performance of the proposed estimation method was evaluated by computer simulation and human experimental studies in an inhomogeneous three-concentric sphere head model. The present simulation results indicated that the equivalent dipole sources was accurately estimated by ICA and dipole imaging. We also applied the proposed method to human visual evoked potential.

DOI： 10.1109/IEMBS.2006.259907

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

We explored suitable estimation method for equivalent dipole sources in the brain. In a previous study, we solved an inverse problem that estimated an equivalent dipole-layer distribution from the scalp electroencephalogram by a spatio-temporal inverse filters constructed with parametric projection filter. In the present study, we estimated equivalent dipole sources from dipole layer distributions. Moreover, to identify the number, position, and moment of equivalent dipole sources, we separated each dipole layer distribution using independent component analysis (ICA). The performance of the proposed estimation method was evaluated by computer simulation and human experimental studies in an inhomogeneous three-concentric sphere head model. The present simulation results indicated that the equivalent dipole sources was accurately estimated by ICA and dipole imaging. We also applied the proposed method to human visual evoked potential.

DOI： 10.1109/IEMBS.2006.259907

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：International Society for Bioelectromagnetism  

The objective of this study is to explore suitable spatial filters for inverse estimation of cortical equivalent dipole layer imaging from the scalp electroencephalogram. The effects of incorporating signal and noise covariance into inverse procedures were examined by computer simulations and experimental study. The parametric projection filter (PPF) and parametric Weiner filter (PWF) were applied to an inhomogeneous three-sphere head model under various noise conditions. The present simulation results suggest that the PWF has better performance especially when the correlation between the signal and noise is high. The proposed methods were applied to self-paced movement-related potentials in order to identify the anatomic substrate locations of neural generators. The proposed methods demonstrated that the contralateral premotor cortex was preponderantly activated in relation to movement performance.

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：電子情報通信学会  

物理乱数を生成する方法の一つとして，電気信号を用いることが挙げられる．従来は，電気信号から乱数を発生させる場合，信号のレベルに関ししきい値を設けそれを超えるか超えないかを判定し"0"，"1"を割り付ける方法などが取られてきた．本論文では，A-D変換器の最下位ビットを用いることによって，従来法では実現が困難であった乱数の高速生成が可能であることを示した．更に，特殊な雑音発生器を用いずに，発振器の揺らぎによって乱数を生成することが可能であることを示した．

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その他リンク： http://hdl.handle.net/10191/8288

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：International Society for Bioelectromagnetism  

The objective of this study is to explore suitable spatial filters for inverse estimation of cortical equivalent dipole layer imaging from the scalp electroencephalogram. The effects of incorporating signal and noise covariance into inverse procedures were examined by computer simulations and experimental study. The parametric projection filter (PPF) and parametric Weiner filter (PWF) were applied to an inhomogeneous three-sphere head model under various noise conditions. The present simulation results suggest that the PWF has better performance especially when the correlation between the signal and noise is high. The proposed methods were applied to self-paced movement-related potentials in order to identify the anatomic substrate locations of neural generators. The proposed methods demonstrated that the contralateral premotor cortex was preponderantly activated in relation to movement performance.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SCRIPTA TECHNICA-JOHN WILEY & SONS  

The authors previously published a physical method for the generation of random numbers by a variable capacitance parametron, which can generate uniform random numbers without periodicity. It is considered possible to generate random numbers with an ordinary oscillator if the oscillation frequency is made unstable. As a method of introducing instability, frequency modulation of an LC oscillator with shot noise is considered. The present paper describes experiments with an LC oscillator to which shot noise is applied. An evaluation of statistical randomness (FIPS 140-2) is carried out for the generated number sequence as cryptographic random numbers. It is shown that generation of random numbers is possible. (C) 2005 Wiley Periodicals, Inc.

DOI： 10.1002/ecjc.20149

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出版者・発行元：The Society of Life Support Engineering  

DOI： 10.5136/lifesupport.17.Supplement_38

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：電子情報通信学会  

筆者らは先に,周期性のない一様乱数を発生する物理乱数発生法として「可変容量パラメトロンによる物理的乱数発生法」を発表した.一般の発振器でも発振周波数を不安定にすれば乱数を発生できると考えられる.不安定にする方法としてLC発振回路をショット雑音で周波数変調することを考えた.本論文では,実際にショット雑音を印加したLC発振回路で実験を行い,生成された数字列について暗号用乱数としての統計的乱数性(FIPS140-2)の評価を行い,乱数の発生が可能であることを示した.

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その他リンク： http://hdl.handle.net/10191/20264

記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

In the present study, we explore suitable spatio-temporal filters for inverse estimation of an equivalent dipole-layer distribution from the scalp electroencephalogram (EEG) for imaging of brain electric sources. We propose a time-varying parametric projection filter (tPPF) for the spatio-temporal EEG analysis. The performance of this tPPF algorithm was evaluated by computer simulation studies. An inhomogeneous three-concentric-spheres model was used in the present simulation study to represent the head volume conductor. An equivalent dipole layer was used to represent equivalently brain electric sources and estimated from the scalp potentials. The tPPF filter was tested to remove time-varying noise such as instantaneous artifacts caused by eyes-blink. The present simulation results indicate that the proposed time-variant tPPF method provides enhanced performance in rejecting time-varying noise, as compared with the time-invariant parametric projection filter.

DOI： 10.1109/TBME.2004.824142

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

A communication interface controlled by eye movements and voluntary eye blink has been developed for disabled individuals who have motor paralysis and therefore cannot speak. Horizontal and vertical electro-oculograms were measured using two surface electrodes referring to an earlobe electrode. Four directional cursor movements and one selection were realized by logically combining the detected two channel signals. Virtual input experiments were conducted on a virtual screen keyboard. Its usability and accuracy were improved using our proposed method.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：ELSEVIER SCIENCE BV  

We explore suitable spatiotemporal filters for inverse estimation of an equivalent cortical dipole layer (DL) distribution from the scalp electroencephalogram (EEG) for imaging of brain electric sources. We have previously developed the parametric projection filter (PPF)-based cortical dipole layer imaging technique, which allows estimating cortical dipole layer inverse solutions in the presence of noise covariance. We have expanded the PPF to the time-varying filter in order to handle the spatiotemporally varying nature of brain electrical activity. The present simulation results indicate that the estimation error is reduced substantially by taking the spatiotemporal properties of the noise into consideration, such as eye-blink artefacts, and the proposed time-variant PPF method provides enhanced performance in rejecting time-varying noise. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ics.2004.05.149

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：ELSEVIER SCIENCE BV  

We explore suitable spatiotemporal filters for inverse estimation of an equivalent cortical dipole layer (DL) distribution from the scalp electroencephalogram (EEG) for imaging of brain electric sources. We have previously developed the parametric projection filter (PPF)-based cortical dipole layer imaging technique, which allows estimating cortical dipole layer inverse solutions in the presence of noise covariance. We have expanded the PPF to the time-varying filter in order to handle the spatiotemporally varying nature of brain electrical activity. The present simulation results indicate that the estimation error is reduced substantially by taking the spatiotemporal properties of the noise into consideration, such as eye-blink artefacts, and the proposed time-variant PPF method provides enhanced performance in rejecting time-varying noise. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ics.2004.05.149

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SCHATTAUER GMBH-VERLAG MEDIZIN NATURWISSENSCHAFTEN  

Objectives: The objective of this study was to explore suitable spatial filters for inverse estimation of cortical potentials from the scalp electroencephalogram. The effect of incorporating noise covariance into inverse procedures was examined by computer simulations and tested in human experiment.
Methods: The parametric projection filter, which allows inverse estimation with the presence of information on the noise, was applied to an inhomogeneous three-concentric-sphere model under various noise conditions in order to estimate the cortical potentials from the scalp potentials. The method for determining the optimum regularization parameter, which can be applied for parametric inverse techniques, is also discussed.
Results. Human visual evoked potential experiment was carried out to examine the performance of the proposed restoration method. The parametric projection filter gave more localized inverse solution of cortical potential distribution than the truncated SVD and Tikhonov regularization.
Conclusion: The present simulation results suggest that incorporation of information on the noise covariance allows better estimation of cortical potentials, than inverse solutions without knowledge about the noise covariance, when the correlation between the signal and noise is low.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

The objective of this study was to explore suitable spatial filters for inverse estimation of cortical potentials from the scalp electroencephalogram. The effect of incorporating noise covariance into inverse procedures was examined by computer simulations. The parametric projection filter, which allows inverse estimation with the presence of information on the noise covariance, was applied to an inhomogeneous three-concentric-sphere model under various noise conditions in order to estimate the cortical potentials from the scalp potentials. The present simulation results suggest that incorporation of information on the noise covariance allows better estimation of cortical potentials, than inverse solutions without knowledge about the noise covariance. when the correlation between the signal and noise is low. The method for determining the optimum regularization parameter, which can be applied for parametric inverse techniques, is also discussed.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SCRIPTA TECHNICA-JOHN WILEY & SONS  

In the present study, a random number generator which physically produces nonperiodic uniform random number was developed using the parametron principle. The parametron is an oscillation circuit at one-half of the excited frequency. The phase of the parametron cannot be predicted because it depends on the noise in the parametron circuit. The random number was generated by detecting the unpredictable phase. The randomness of the data generated by the present method was confirmed by the spatial distribution and by statistical random tests. (C) 2002 Wiley Periodicals, Inc.

DOI： 10.1002/ecjc.10040

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：電子情報通信学会  

本論文では,周期性のない一様乱数を発生する物理乱数生成法として,パラメトロンの原理に注目した.パラメトロンは,励振した周波数の2分の1で発振を起こす回路であり,その位相は回路内に存在する雑音によって決定されるため予測することができない.この予測不可能な位相を検出することによって,乱数を発生させる装置を開発した.度数分布と統計的乱数検定より,本方式で生成された乱数が一様であることを確認した.

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その他リンク： http://hdl.handle.net/10191/20247

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

The objective of this study is to explore suitable spatial filters for inverse estimation of cortical equivalent dipole layer imaging from the scalp electroencephalogram. The effects of incorporating signal and noise covariance into inverse procedures were examined by computer simulations. The parametric projection filter (PPF) and parametric Weiner filter (PWF) were applied to an ideal 3D head model under various noise conditions. The present simulation results suggest that the PPF has better performance than the PWF, when the correlation between the signal And noise is low, and the PWF performs better than the PPF when the correlation is high.

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3191/thermalmedicine.17.231

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER  

In the present study, spatial filters for inverse estimation of an equivalent dipole layer from the scalp-recorded potentials have been explored for their suitability in achieving high-resolution electroencephalogram (EEG) imaging. The performance of the parametric projection filter (PPF), which we propose to use for high-resolution EEG imaging, has been evaluated by computer simulations in the presence of a priori information on noise. An inhomogeneous three-concentric-sphere head model was used in the present simulation study to represent the head volume conductor. An equivalent dipole layer was used to model brain electric sources and estimated From the scalp potentials. Various noise conditions were simulated and the parametric projection filter was compared with standard regularization procedures such as the truncated singular value decomposition (TSVD) and the Tikhonov regularization (TKNV). The present simulation results suggest that the proposed method performs better than that of commonly used inverse regularization techniques, such as the general inverse using the TSVD and the TKNV, when the correlation between the original source distribution and the noise distribution is low, and performs similarly when the correlation is high. A method for determining the optimum regularization parameter, which can be applied to parametric inverse techniques, has also been developed. (C) 2001 Biomedical Engineering Society.

DOI： 10.1114/1.1366674

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

The restoration of biomedical images that have been blurred due to body movement are discussed. The observation system for these images is described using a mathematical operator and coordinate transformations. And a band-suppressed restoration filter composed of a series of such operators is proposed for improving the quality of images. In addition, redundancy is introduced into these restoration filters in order to suppress additive noise. The proposed method is applied to blurred X-ray images of a bone model of the elbow joint. The optimum position and number of markers, which are attached to the subject as a reference signal, are also discussed.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SCHATTAUER GMBH-VERLAG MEDIZIN NATURWISSENSCHAFTEN  

The restoration of X-ray images that have been blurred due to body movement are discussed. The observation system for these images is described using a mathematical model, and several restoration filters composed of a series of such models are proposed. These filters restore band-suppressed approximations of the original images. In addition, redundancy is introduced into these restoration filters in order to suppress additive noise. These filters are expanded to be applicable not only to parallel translations, but also to rotations by coordinate transformation. The proposed methods are applied to blurred X-ray images of a bone model of the elbow joint. The parameters of the restoration filter are estimated using a marker attached to the subject as a reference signal.

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.11239/jsmbe1963.38.102

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

The objective of this study was to explore suitable spatial filters for inverse estimation of cortical equivalent dipole layer from the scalp EEG The performance of the Weiner filter and the projection filter as a restoration filter was examined by computer simulations. The parametric Weiner filter (PWF) and the parametric projection filter (PPF) were applied to an idealized 3D head model under the various noise conditions in order to estimate the dipole layer distribution from scalp potentials. The PPF and PWF algorithms were compared with commonly used inverse regularization techniques, such as the general inverse using the truncated singular value decomposition (TSVD) and the Tikhonov regularization (TKNV), The present simulation results suggest that the PWF and PPF perform better than that of the TSVD and the TKNV in the condition of edge-concentrated non- uniform noise when the correlation between the signal and noise is low.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

In the present paper we shall examine the real-time restoration of biomedical signals under additive noises. Biomedical signals measured by instruments such as catheter manometers, ambulatory electrocardiographs and thermo-dilution sensors are susceptible to distortion and noise. Therefore, such signals must be restored to their original states. In the present study, nonstationary biomedical signals are observed and described using a mathematical model, and several restoration filters that are composed of a series of applications of this model are proposed. These filters restored band-limited approximations of the original signals in real-time. In addition, redundancy is introduced into these restoration filters in order to suppress additive noise. Finally, an optimum filter that accounts for restoration error and additive noise is proposed.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

In this paper we examined the restoration of X-ray images blurred by body motion. We described the observation of these images with a mathematical model and proposed several restoration filters composed of series of such models. These filters restored band-suppressed approximations of the original images in real-time. Furthermore, we introduced redundancy into these restoration filters in order to suppress the additive noise. We applied these methods to blurred X-ray images of an elbow bone model. The parameters of the restoration Filter were estimated by using a marker attached to the subject as a reference signal.

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

CiNii Article

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本ハイパーサーミア学会  

組織内癌温熱療法の一つである針電極によるRF加温の場合, 加温領域が狭いという問題があった.本研究では, 加温対象に食塩水を注入し, 導電率を高めることによって, 加温領域を拡大することを試みた.切離した豚の肝臓を対象として加温実験を行った結果, 食塩水の濃度が高いほど, また針電極の直径が太いほど加温領域が拡大した.Interstitial hyperthermia by using a needle electrode has problem that heating range is too narrow to apply for massive tissues. In this study, we tried to extend the heating range by using high-conductivity saline pouring into the heating object. In experiments of RF power heating using pig livers, the higher salt concentration or the thicker the diameter of the needle electrode, the wider the heating range.

DOI： 10.3191/thermalmedicine.13.68

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その他リンク： http://search.jamas.or.jp/link/ui/1999206321

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3191/thermalmedicine.12.401

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本ハイパーサーミア学会  

本研究では, 腹腔鏡を使用した手術を想定し, 変形可能な電極を内部RF加温のアプリケータとした腹部臓器の癌温熱治療を実現するための基礎的加温特性を調べることを目的とする.加温電極として変形自由度が大きい金属製の鎖状のものを用い, 折り返して設置した場合, 螺旋状に設置した場合, 放射状に設置した場合, および重ね合わせて設置した場合の加温特性を調べた.生体と電気的特性が等価なファントムを対象として加温を行った結果, 不関電極に平行になるように重ね合わせて設置することにより, 電極の直径の範囲で集中的な加温を実現することができた.<BR>腹腔鏡手術を想定して, 変形自由度の大きい鎖電極を加温電極として用いた内部加温法に関する基礎実験を行った.鎖電極を4種類の形状にした加温実験を行った結果, 不関電極と平行になるように鎖電極を重ね合わせて配置することによって, 一枚の平面状電極と同様に, 電極に挾まれた領域を均一に加温することができ, 癌組織のみを有効に加温できる可能性を示した.<BR>今後の課題として, 更に加温特性が良好で変形自由度が大きい電極を選定すること, および動物実験により加温特性を確認することなどがあげられる.

DOI： 10.3191/thermalmedicine.12.393

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その他リンク： https://jlc.jst.go.jp/DN/JALC/00083435454?from=CiNii

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

Adapting the principle of parametron oscillation, a small implantable temperature sensor requiring no internal power supply is described. Since this sensor's oscillation frequency is half that of the excitation frequency, the oscillated signal can be measured from the reception side, free of any signal, interference, simply by positioning the sensor and the excitation antenna so that; 1) they are separated up to 95 cm in the air; 2) a 41 cm gap, the phantom equivalent of the thickness of the human abdomen maintain between them. In the temperature-dependent quartz resonator sensor, oscillation occurs only when frequency and temperature correspond. The excitation power is then adjusted so that the frequency bandwidth narrows. As a result, the margin of error in measuring the temperature is minimized; (+/- 0.07 degrees C).

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

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記述言語：日本語   出版者・発行元：Japanese Society for Thermal Medicine  

リエントラント型空洞共振器アプリケータは, 2つのリエントラントを内部に持つ空洞共振器によって構成される癌温熱治療用アプリケータである.本アプリケータによれば, 被加温体の中心に円柱状の高温領域を発生させ得ることが数値解析によって確認されている.本論文では, 実際に加温実験を行い, 直径24cm, 厚さ12cmまでの円筒型の均質ファントムに対して中心部が集中的に加温されることを示した.また, 集中加温を実現するためには, ファントムの厚さをリエントラント間隔の40%程度に保ち, 電界集中具の直径をファントムの厚さの1.5倍程度に大きくし, かつ高周波電力増幅器と空洞共振器の結合を臨界状態にする必要があることを示した.

DOI： 10.3191/thermalmedicine.12.401

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

When measuring the ejection fraction for the evaluation of the ventricular pumping function by means of the thermodilution technique, the slow response a conventional thermistor has caused it to be considered unsuitable, and fast thermistors have been proposed as an alternative. However, in this paper we propose improving the time-domain response of a conventional thermistor using a signal processing technique composed of a series of first-order high-pass filters which is known as the natural observation system. We considered the rise time of the thermistor in response to a step temperature change to effect correction for the measurement of the ejection fraction. The coefficients of the natural observation system were calculated by minimizing the square error between the step-response signal of the thermistor and the band-limited reference signal. In an experiment using a model ventricle, the thermodilution curve obtained from a conventional thermistor was improved using the proposed technique, thus enabling successful measurement of the ejection fraction of the ventricles.

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：JAPANESE SOCIETY FOR ARTIFICIAL ORGANS  

時間周波数解析の手法(Wigner-ViUe法)を用いて、SJM弁閉鎖音の実験的解析を行った。閉鎖音の時間周波数分布は1.3～1.5KHzに最大ピークを有し、5KHzまで達していたが、周波数が高くなるほどパワー減弱した。弁サイズを大きくすると1.5～3KHzの領域の出現時間がやや延長した。擬似血栓の付着により、3～5KHzの領域のパワーの減弱が認められた。擬似血栓を大きくすると、1,5～3KHzの領域のパワーの減弱も認められ、さらにその出現時間も短縮し、最終的には、1KHzをピークとする連続性の周波数分布を認めるだけとなった。本法によるSJM弁閉鎖音の解析は、血栓付着により、1.5～5KHzの周波数域のパワーの減弱とともに分布出現時間の短縮も認められ、弁機能不全を早期に、より明確に判断できる可能性があると考えられた。

DOI： 10.11392/jsao1972.23.151

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その他リンク： http://search.jamas.or.jp/link/ui/1994219293

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：I E E E  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRON INFO COMMUN ENG  

We use the B spline function and apply the Oslo algorithm to minimize the number of control points in electrocardiogram (ECG) waveform compression under the limitation of evaluation indexes. This method is based on dynamic programming matching to transfer the control points of a reference ECG waveform to the succeeding ECG waveforms. This reduces the execution time for beat-to-beat processing. We also reduced the processing time at several compression stages. When the difference percent normalized root mean square difference is around 10, our method gives the highest compression ratio at a sampling frequency of 250 Hz.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRON INFO COMMUN ENG  

The pressure waveforms indicated on a catheter manometer system are subject to serious distortion due to the resonance of the catheter itself, or the compliance of a particular transducer. Although several methods have been proposed for improving those characteristics, they have never been put into practice. We have focused on the transfer function of the catheter manometer, and made a pilot system, using the natural observation method. This method has been suggested as a means of studying the structure of the instantaneous waveform. In this manner, we were able to increase the bandwidth in the frequency domain and reduce the ringing in the time domain. Correction was performed automatically, using a step wave. Reproduction of the waveform with a flushing device, was a task of equal simplicity, that allowed us to estimate the system parameters so that the response waveform became step-like. In the experiment, our system provided distortion-free left-ventricular pressure waveform measurements and exact evaluation of the cardiac pumping system. The values obtained came much closer to the original figures arrived at by the catheter-tip manometer system.

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：JAPANESE SOCIETY FOR ARTIFICIAL ORGANS  

実験的に圧及び回路内液の性状の違いがSJM弁閉鎖音周波数特性に与える影響をFFT法を用いて検討した。回路内に水を充填した場合0.8及び2.5KHzにピークを有した。グリセリンでは0.7及び2.1KHzにピークを有したが、2.1KHzのピークと3.0KHz以上の高周波数域で水の場合より減衰した。グリセリンを充填し閉鎖圧を50から150mmHgまで変化させたが、周波数特性に変化を認めなかった。フィブリン糊をSJM弁輪に付着させると、水、グリセリンともに0.7から2.5KHzの間のピークは各々減衰し平坦化する傾向を示した。以上よりSJM弁閉鎖音周波数特性は閉鎖圧の影響は受けないが、回路内液の影響を受けると考えられた。フィブリン糊の付着により、水及びグリセリンで同様の変化を示し、これは血栓付着による一般的な変化と考えられた。臨床においては、シミュレーターと臨床の共通性と差を念頭におき検討すべきと考えられた。

DOI： 10.11392/jsao1972.21.635

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：JAPANESE SOCIETY FOR ARTIFICIAL ORGANS  

シミュレーターを用いてSJM弁閉鎖音の周波数特性を検討し、臨床例と比較した。録音した閉鎖音はデジタル化、FFT処理を行いパワースペクトル曲線で表わした。正常のSJM弁閉鎖音は0.6KHz付近にピークを有し、7KHz付近まで徐々に減衰した。また1.2、1.8、2.4、3.6KHz付近等に小さなピークを有し、SJM弁閉鎖音の固有周波数0.6KHzの高調波が現われると考えられた。正常と考えられる臨床例でも、小さなピークは認めないものの、0.6KHz付近にピークを有する同様の波形を呈した。疑血栓としてフィブリン糊を付着させたSJM弁閉鎖音のスペクトル曲線では、正常弁に比べ0.6～3KHzのパワーの減衰を来した。臨床例では、肺動脈弁位血栓弁の閉鎖音や、脳血栓症を来した僧帽弁位SJM弁の閉鎖音でも同様の所見が認められた。この領域のパワーの減衰がSJM弁の血栓付着を予測する指標になると考えられた。

DOI： 10.11392/jsao1972.20.915

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その他リンク： http://search.jamas.or.jp/link/ui/1992029100

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Society for Medical and Biological Engineering  

The ambulatory ECG system has been used not only in detecting arrhythmia but also in the diagnosis of myocardial ischemia. Therefore, it is necessary to reproduce ECG waveforms as accurately as possible. However, ambulatory ECG waveforms which are in clinical use are apt to be distorted because the frequency responses do not satisfy the AHA (American Heart Association) recommendation which is well accepted as the standard of the conventional ECG system. An improvement of frequency response is reported here using a compensation circuit, whose theory is based on the natural observation method. Since our system is adjusted with square waveforms and composed of a simple analog circuit, it can be compensated easily in real time. In this paper, our newly developed system and various improved ECG signals are presented and compared with conventional ECG signals. As a result, we could obtain less distorted waveforms than from commercially available devices. This new approach enables us to obtain diagnostic information of the distortion-free ST segment in ECG waveforms.

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記述言語：日本語   出版者・発行元：JAPANESE SOCIETY FOR ARTIFICIAL ORGANS  

僧帽弁位SJM弁11例について閉鎖音周波数スペクトルをfast Fourier transform (FFT)により検討した。閉鎖音は左第6肋間鎖骨中線で行い、1 KHz high pass filterを通過させた後、デジタル化しFFT処理を行なった。9例で2葉の閉鎖音は分離して記録されたが、そのPower spectrum curveは1 KHzにピークを有し5～7KHzまで徐々に減衰しプラトーとなった。術後8年4ケ月の1例で2.5KHz付近に、術後4年6ケ月の1例で1.5KHz付近にdipを認めた。これらは大動脈、肺動脈弁位sJM弁閉鎖音の特徴と類似しており、僧帽弁位においても同一手法で血栓弁を早期発見できる可能性があると考えられた。

DOI： 10.11392/jsao1972.19.382

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記述言語：日本語   出版者・発行元：JAPANESE SOCIETY FOR ARTIFICIAL ORGANS  

SJM弁閉鎖音周波数スペクトルをfast Fourier transform (FFT)法により検討した。閉鎖音の録音は第三肋間胸骨左縁で行い、A-Dコンバーターにてデジタル化した後、1KHz high pass filterを通過させFFT処理を行った。4例の正常と考えられた大動脈弁位SJM弁の閉鎖音は1.2KHz付近にピークを持ち、その後7.5KHzまで緩やかに減衰した。これに対し間歇的開放位固定をきたした肺動脈弁位SJM弁の1例と、1葉の開放角が低下した肺動脈弁位及び大動脈弁位SJM弁のそれぞれ1例では、2.5KHz付近に深いdipを認めた。血栓弁の早期発見の上でこの2.5KHz付近のdip形成は重要な意義を持つと考えられる。

DOI： 10.11392/jsao1972.18.694

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.11239/jsmbe1963.26.133

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記述言語：日本語   掲載種別：記事・総説・解説・論説等（大学・研究所紀要）   出版者・発行元：計測自動制御学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

新潟大学工学部福祉人間工学科は新潟県視覚障害者福祉協会と協力して,平成15年より新潟駅南キャンパスにおいて「視覚障害者のためのパソコン講習」を開始し,現在までに12回実施してきた.本稿では新潟大学の地域貢献の取り組みのひとつであるこの講習会について報告する.

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記述言語：日本語   掲載種別：記事・総説・解説・論説等（商業誌、新聞、ウェブメディア）   出版者・発行元：株式会社エイチ．ケイコネクション  

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記述言語：日本語   掲載種別：記事・総説・解説・論説等（商業誌、新聞、ウェブメディア）   出版者・発行元：高松機械工業株式会社  

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記述言語：日本語   出版者・発行元：社団法人日本生体医工学会  

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記述言語：日本語   出版者・発行元：社団法人日本生体医工学会  

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記述言語：日本語   出版者・発行元：社団法人日本生体医工学会  

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記述言語：日本語   出版者・発行元：社団法人日本生体医工学会  

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記述言語：日本語  

J-GLOBAL

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記述言語：英語   出版者・発行元：日本ハイパーサーミア学会  

Many heat applicators for hyperthermia have been developed ; however, in treatment of noninvasive cancer they can heat only the body surface. At present, it is difficult to selectively heat deep-seated tumors. It is desirable to develop an applicator with the potential for heating a limited region, but achieving this objective is impossible with present technology. Therefore, our goal is to develop an applicator that can uniformly heat to deep regions of the human body. In this paper, we describe fundamental heating characteristics of an RF hyperthermic system using a rectangular resonant cavity applicator for deep-seated tumors. First, electromagnetic and heat-transfer equations were solved to investigate fundamental heating characteristics of the resonant cavity applicator. In the experiments, a torso-shaped dielectric phantom, which has electrical constants close to human muscle, was used. In comparisons of the measured and calculated results, the tendencies of both heat distributions were in accordance. These results indicated the possiblility of heating deep regions ; thus, this applicator has the potential to heat deep-seated tumors.多くの癌温熱治療用加温装置が開発されている. しかしながら. 非侵襲な癌温熱治療用加温装置は, 人体表面近傍のみの加温が可能である. 現状では, RF波を用いて深部に位置する癌を選択的に加温することは不可能である.局部加温の可能性を持つ装置を開発することが望ましいが, この目標を達成することは, 現状の技術では不可能である. それゆえ, 我々は, 人体深部までを一様に加温する装置を開発することを目標とした.この論文では, 立体空洞共振器を用いた深部癌温熱治療用RFシステムの基礎的な加温特性について述べる. 初めに, 基本加温特性を調べるためにMaxwellの方程式と熱伝導―熱伝達方程式を解いた. 次に, 人体筋肉の電気特性を模した誘電体ファントムを使用し, 加温実験を行った. 実験結果と計算結果を比較したところ, 深部加温できる傾向は一致した. すなわち, 深部癌温熱治療用加温装置としての可能性を持つことが分かった.

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記述言語：日本語   出版者・発行元：社団法人日本生体医工学会  

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記述言語：日本語   出版者・発行元：社団法人日本生体医工学会  

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記述言語：日本語  

J-GLOBAL

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記述言語：日本語  

J-GLOBAL

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

聴覚に異常が見られた場合や補聴器をフィツティングする際の聴覚検査では,一般的に聴性脳幹反応(ABR)などの脳波検査が行われる.通常,ABRを検出するためには,被検者に1,000回以上聴覚刺激を与えなければならない.本研究では. ABRがfar-field ootentials であることを考慮し,多チャネル化することにより刺激回数を減らすことを考えた.また,一刺激毎のデータを統計的に検証することにより,加算平均処理の精度向上を図った.頭頂近傍9チャネルでABRを検出する実験を行った.刺激後10msのデータを一刺激毎に評価し,選別したデータのみで加算平均した結果,加算目数が少ないにも関わらず,従来の加算平均処理のABR波形と同等の結果を得ることができた.

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その他リンク： http://search.jamas.or.jp/link/ui/2004071040

記述言語：日本語   出版者・発行元：社団法人日本生体医工学会  

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記述言語：日本語   出版者・発行元：社団法人日本生体医工学会  

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記述言語：日本語   出版者・発行元：社団法人日本生体医工学会  

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記述言語：日本語   出版者・発行元：社団法人日本生体医工学会  

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記述言語：日本語   出版者・発行元：社団法人日本生体医工学会  

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記述言語：日本語   出版者・発行元：社団法人日本生体医工学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

In the present study, random number generator, which physically produces non-periodic uniform random number, was developed using the principle of parametron. The parametron is the oscillation circuit of one half of the excited frequency. The phase of the parametron cannot predict because it is decided by the noise in the parametron circuit. The random number was generated by detecting the unpredictable phase. The randomness of the data generated by the present method was confirmed by the space distribution and statistical random tests.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

脳波として観測される頭皮電位から, ダイポールイメージング手法を用いて脳内の信号源つまりダイポールソースを推定する方法を提案した.ダイポールイメージングは, 頭皮電位から脳内に設置した仮想ダイポール層上の信号強度分布を推定するという逆問題を解くための手法であり, 信号源の数, 方向に制約条件がないという利点を持つ.本研究では, コンピュータシミュレーションにより, 脳内深度の異なる複数のダイポール層信号強度分布から, 3次元上の強度分布を解析することで, 信号源の位置, モーメントを推定した.

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その他リンク： http://search.jamas.or.jp/link/ui/2002160648

記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

生体深部の癌組織に対する局所加温を目的とした空洞共振器アプリケータが開発されている.更に人体の厚さを模した被加温体に対して深部加温を実現するため, 共振器内の上下にある二つの突起(リエントラント)の内の上部を共振器から切り離し, リエントラントの距離を近づけることにより, 被加温体を集中的に加温する方法が考案された.本研究では, 電磁界解析と熱伝導解析の解法を差分法で統一し, 改良型リエントラントを用いた空洞共振器アプリケータの数値解析を行った.加温実験結果との比較を行った結果, 温度の絶対値には違いが見られたが, 周辺部分と中央付近の温度が〓くなるという温度分布の傾向は同様の結果が得られた.今後, 共振器モデルに見合った格子生成を行うことにより, より有効な加温装置の設計が可能であることが示唆された.

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記述言語：日本語   出版者・発行元：(一社)日本ハイパーサーミア学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

音響分析や音声認識を目的とした, 聴覚機構のモデル化に関する研究が行われている. 数学的に整備された変換理論を用いた正規型自然観測フィルタによる疑似聴覚フィルタが提案されているが, 人の聴覚機構が有する非線形な信号処理を実現していない。本研究では, 正規型自然観側フィルタの1次の基本構成要素を2次へと拡張し, 非線形性を持たせた聴覚機構モデルを提案する。具体的には2次のフィルタに尖鋭度Qを導入し, 入力音圧レベルによりフィルタの特性を変化させることにより, より人の聴覚機構に近いモデルを構成した.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

観測された画像は観測系の影響によって劣化を受けている場合が多い. 本研究では観測系の構造は既知で, 劣化の程度を表すパラメータは未知である場合, 観測画像からもとの画像を復元することを問題とする. 時系列信号の帯城制限されたものを復元する有限項の復元フィルタが提案されている. この復元フィルタを2次元に拡張し, 画像を対象とした復元フィルタを構成する. シミュレーションによって本復元フィルタの有効性を確認する.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

観測された画像は観測系の影響によって劣化を受けている場合が多い.本研究では劣化関数は既知で,劣化の程度を表すパラメータは未知である場合において,劣化画像からもとの画像を復元することを検討する.原画像は推定されたパラメータより復元されるが,推定値には誤差が含まれる.そこで推定誤差を補うために2次元自然観測法を適用する.また,原画像が既知であるステップ状の画像を基準画像として用いて,劣化パラメータ及び復元フィルタの係数を推定する.シミュレーション実験によって空間不変のバターワース型,ガウス型及びSinc関数型の推定誤差による影響について考察し,本手法の有効性を確かめる.

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