IEEJ Transactions on Electronics, Information and Systems
Online ISSN : 1348-8155
Print ISSN : 0385-4221
ISSN-L : 0385-4221
Volume 130 , Issue 3
Showing 1-27 articles out of 27 articles from the selected issue
Special Issue on “Medical Engineering and Assistive Technology for Human”
Preface
Special Issue Paper
<Biomedical Engineering>
  • Yohei Nomoto, Kazuhiko Yamashita, Tetsuya Ohya, Hironori Koyama, Masas ...
    2010 Volume 130 Issue 3 Pages 370-375
    Published: March 01, 2010
    Released: March 01, 2010
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    There is the increasing concern of the society to prevent the fall of the aged. The improvement in aged people's the muscular strength of the lower-limb, postural control and walking ability are important for quality of life and fall prevention. The aim of this study was to develop multiple evaluation methods in order to advise for improvement and maintenance of lower limb function between aged and young. The subjects were 16 healthy young volunteers (mean ± S.D: 19.9 ± 0.6 years) and 10 healthy aged volunteers (mean ± S.D: 80.6 ± 6.1 years). Measurement items related to lower limb function were selected from the items which we have ever used. Selected measurement items of function of lower are distance of extroversion of the toe, angle of flexion of the toe, maximum width of step, knee elevation, moving distance of greater trochanter, walking balance, toe-gap force and rotation range of ankle joint. Measurement items summarized by the principal component analysis into lower ability evaluation methods including walking ability and muscle strength of lower limb and flexibility of ankle. The young group demonstrated the factor of 1.6 greater the assessment score of walking ability compared with the aged group. The young group demonstrated the factor of 1.4 greater the assessment score of muscle strength of lower limb compared with the aged group. The young group demonstrated the factor of 1.2 greater the assessment score of flexibility of ankle compared with the aged group. The results suggested that it was possible to assess the lower limb function of aged and young numerically and to advise on their foot function.
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  • Hajime Tsujimura, Hiroya Okazaki, Mitsumi Yamashita, Hideaki Doi, Masa ...
    2010 Volume 130 Issue 3 Pages 376-382
    Published: March 01, 2010
    Released: March 01, 2010
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    Disuse atrophy of various organs related to swallowing functions is one of the causes of swallowing disorders. In the present study, a system to measure swallowing frequency in a nonrestrictive manner over a long period of time was developed. In the present method, a throat microphone is attached to the neck region to record oral sounds. The reliability of the method is confirmed by recognizing 86% of swallowing sounds. Since the interval of swallowing in a complete rest is getting longer according to aging, the swallowing function is possibly getting weaker.
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  • Yuji Ohta, Nobuhisa Motooka, Itiro Siio, Koji Tsukada, Keisuke Kambara
    2010 Volume 130 Issue 3 Pages 383-387
    Published: March 01, 2010
    Released: March 01, 2010
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    Computers become smaller and cheaper from day to day, and the utilization, as daily life equipments, is now becoming ubiquitous. Therefore, it's essential to discuss the development of applications, as well as the installation of ubiquitous computing technologies into our daily living environments. Based on this idea, in order to investigate how ubiquitous computing can be used in the most efficient way, an experimental house, Ocha House, has been constructed in the campus of Ochanomizu university in 2009. In this study, we described the feature of the design of the experimental house and proposed a non-invasive gait monitoring technique as a healthcare application. Specifically, five wireless accelerometers were fixed on the floor of the house, and the floor vibration was measured when the subject walked along the accelerometers. As a result, the floor acceleration intensity was found to surge at the ground contact, and the gait cycle could be detected. By combining the simple acceleration sensors and the housing structures, human motion monitoring would become less invasive.
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  • Mitsuhiro Ogihara, Kenzo Takahashi, Mikio Mori, Shuji Taniguchi, Shozo ...
    2010 Volume 130 Issue 3 Pages 388-393
    Published: March 01, 2010
    Released: March 01, 2010
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    Recently, the digital and LSI based miniaturization technologies drastically have changed the hearing aids from the conventional single function of amplification to multiple functions. However, since the conventional hearing aids mostly control the flat gain at the center of a frequency band divided every octave to recover the auditory loss of users, so that the discontinuous gain tends to deteriorate the hearing quality due to the unnatural saw-teeth figured error. This paper proposes a solution of digital hearing aid which can be independently controlled at each audiogram test frequency and provide superb voice quality with less noise due to continuous variable gain characteristics in a wide dynamic range. The simulation results show the outstanding effect of the proposed scheme in the voice quality improvement which potential hearing aid users have considered to be a key to satisfy them.
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  • Tsuyoshi Nakayama, Yuka Miyaji, Seishi Kato, Nobuhisa Sakurada, Noriyu ...
    2010 Volume 130 Issue 3 Pages 394-400
    Published: March 01, 2010
    Released: March 01, 2010
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    This paper shows a mobile phone application for supporting persons with higher brain dysfunction (HBD) such as a cognitive disorder, a memory disorder, and an attention-deficit disorder. This application serves them as a schedule manager, an alarm and an instructor of work sequences. The development concept of this application is easy handling and simple display, because persons with HBD are easily bewildered by complex procedures in the work. Five persons with HBD participated in the experiments for assessing the application at the vocational training place. The use of the application resulted in the drastic decrease of the number of errors and the increase of the System Usability Score, indicating that the developed application is useful for persons with HBD especially in performing vocational training tasks such as the use of database software on PC.
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  • Yutaka Suzuki, Mizuya Fukasawa, Takahiro Mori, Osamu Sakata, Asobu Hat ...
    2010 Volume 130 Issue 3 Pages 401-406
    Published: March 01, 2010
    Released: March 01, 2010
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    It is desired to detect stenosis at an early stage to use hemodailysis shunt for longer time. Stethoscope auscultation of vascular murmurs is useful noninvasive diagnostic approach, but an experienced expert operator is necessary. Some experts often say that the high-pitch murmurs exist if the shunt becomes stenosed, and some studies report that there are some features detected at high frequency by time-frequency analysis. However, some of the murmurs are difficult to detect, and the final judgment is difficult. This study proposes a new diagnosis support system to screen stenosis by using vascular murmurs. The system is performed using artificial neural networks (ANN) with the analyzed frequency data by maximum entropy method (MEM). The author recorded vascular murmurs both before percutaneous transluminal angioplasty (PTA) and after. Examining the MEM spectral characteristics of the high-pitch stenosis murmurs, three features could be classified, which covered 85 percent of stenosis vascular murmurs. The features were learnt by the ANN, and judged. As a result, a percentage of judging the classified stenosis murmurs was 100%, and that of normal was 86%.
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  • Akio Nozawa, Keita Karita
    2010 Volume 130 Issue 3 Pages 407-413
    Published: March 01, 2010
    Released: March 01, 2010
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    The objective of this study is to evaluate the effect of daily repetitive mental workload on physiological indices. Especially, the index derived from the nasal skin temperature(NST) measured by the infrared thermography was focused. The NST was the physiological index representing the sympathetic nervous system activity. The NST declines with the sympathetic nervous system's activation. The mental workload causes sympathetic nervous system's activation, so the mental workload can be measured by NST as a declining temperature. We have found that the relationship between the amount of mental workload and the NST declining under time pressure, even more complex stimuli. However, there's no study on evaluating the NST measured for the repetitive mental workload for certain period of time. In this paper, the NST and other physiological indices, which were Fmθ wave component of Electroencephalograms(EEG) and high frequency component(HF) of R-wave interval time series of Electrocardiograms(ECG) were serially measured and evaluated on repetitive mental workload. Significant difference was found between those NST indices in each experiment by paired t-test. A stability of NST as an evaluation index for MWL was proved.
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  • Ryoichi Nakamura, Mikiko Hara, Shigeru Omori, Miyuki Uematsu, Mitsuo U ...
    2010 Volume 130 Issue 3 Pages 414-419
    Published: March 01, 2010
    Released: March 01, 2010
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    To establish safe, precise, and minimally invasive surgery, Computer Aided Surgery (CAS) systems, such as intra-operative imaging and navigation system to detect the location of the target of therapy, and surgical robot system, are very powerful tools. There is strong need to combine these CAS systems for fusion of advanced diagnosis and treatment technologies. In this paper, we introduce our new method to register the intraoperative imaging information, robotic surgery system, and patient using surgical navigation system. Using our Open-MRI navigation system and laser surgery system for neurosurgery, we can make registration between these system and patient precisely. The experimental result shows that the error on the registration between image data and the laser surgery system is low enough to fulfill the requirement of laser surgery system in the use of high-resolution image data. This system realizes the safe, precise and minimally invasive neurosurgery by the combination of intra-operative diagnosis and advanced therapeutic device.
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  • Kazuhiro Tamura, Takamasa Shimada, Yoichi Saito
    2010 Volume 130 Issue 3 Pages 420-427
    Published: March 01, 2010
    Released: March 01, 2010
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    In psychiatry, the sleep stage is one of the most important evidence for diagnosing mental disease. However, when doctor diagnose the sleep stage, much labor and skill are required, and a quantitative and objective method is required for more accurate diagnosis. For this reason, an automatic diagnosis system must be developed. In this paper, we propose an automatic sleep stage diagnosis method by using Self Organizing Maps (SOM). Neighborhood learning of SOM makes input data which has similar feature output closely. This function is effective to understandable classifying of complex input data automatically. We applied Elman-type feedback SOM to EEG of not only normal subjects but also subjects suffer from disease. The spectrum of characteristic waves in EEG of disease subjects is often different from it of normal subjects. So, it is difficult to classifying EEG of disease subjects with the rule for normal subjects. On the other hand, Elman-type feedback SOM Classifies the EEG with features which data include and classifying rule is made automatically, so even the EEG with disease subjects is able to be classified automatically. And this Elman-type feedback SOM has context units for diagnosing sleep stages considering contextual information of EEG. Experimental results indicate that the proposed method is able to achieve sleep stage judgment along with doctor's diagnosis.
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<Systems, Instrument, Control>
  • Hirotoshi Asano, Naoki Sakamoto, Akio Nozawa, Hideto Ide
    2010 Volume 130 Issue 3 Pages 428-432
    Published: March 01, 2010
    Released: March 01, 2010
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    This study is aimed for the development of the quantitative measurement technology of the transient awakening degree fall based on a facial skin temperature change. Generally the characteristic change that accepted sleepiness levels such as eye blink rhythm or the movement of lips by an awakening degree fall appears in the face expression. On the other hand, the facial skin temperature changes by the action of the autonomous nervous system with the awakening degree fall significantly. In this study, we demanded the relevance that there was between this face skin temperature change and a face expression change. And we tried the construction of the model that estimated awakening degree based on a change pattern of the time and space of the facial skin temperature. We used a hierarchical model neural network for the modeling. We learned an explanation variable, face expression evaluation value as a purpose variable by the change pattern of the time and space of the facial skin thermal image. Concretely Speaking, we measured a heat picture, the number of cardiac beats, and facial expression evaluation. And we presumed the facial expression evaluation value from the facial skin temperature using the model. As a result of the experiment, the proposed model showed a possibility that it could presume in the stage of 1 to 3 of a facial expression evaluation value.
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<Intelligence, Robotics>
  • Yusuke Aoki, Kenta Kaneko, Masami Oyamada, Yuuki Takachi, Kohji Masuda
    2010 Volume 130 Issue 3 Pages 433-441
    Published: March 01, 2010
    Released: March 01, 2010
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    We propose a probe scanning support system based on force/visual servoing control for robotic echography. First, we have designed and formulated its inverse kinematics the construction of mechanism. Next, we have developed a scanning method of the ultrasound probe on body surface to construct visual servo system based on acquired echogram by the standalone medical robot to move the ultrasound probe on patient abdomen in three-dimension. The visual servo system detects local change of brightness in time series echogram, which is stabilized the position of the probe by conventional force servo system in the robot, to compensate not only periodical respiration motion but also body motion. Then we integrated control method of the visual servo with the force servo as a hybrid control in both of position and force. To confirm the ability to apply for actual abdomen, we experimented the total system to follow the gallbladder as a moving target to keep its position in the echogram by minimizing variation of reaction force on abdomen. As the result, the system has a potential to be applied to automatic detection of human internal organ.
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<Media Information, User Interface>
  • Tetsuya Yonezawa, Kohichi Ogata, Kohei Matsumoto, Suguru Hirase, Kazuy ...
    2010 Volume 130 Issue 3 Pages 442-449
    Published: March 01, 2010
    Released: March 01, 2010
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    We have developed an eye-gaze interface system. The purpose of this system is to develop an easy to use system for spreading to ordinary people as well as people with motor-disabilities of upper limbs. Our system uses a compact video camera and a Windows PC equipped with a frame grabber.
    This system detects the eye-gaze position on a computer display through the detection of the center of the iris from a captured eye image. When a user gazes at a peripheral point on the display, eye-gaze detection has slightly poorer accuracy because of influences of inner and outer corners of the eye. In this paper, we propose two new procedures to overcome the problem. We show the evaluation of these procedures through the comparing experiments on the accuracy of the eye-gaze estimation.
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<Speech and Image Processing, Recognition>
  • Hiroyuki Nagashima, Tetsumi Harakawa, Kunio Doi
    2010 Volume 130 Issue 3 Pages 450-457
    Published: March 01, 2010
    Released: March 01, 2010
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    We developed a computerized scheme for proper adjustment of display grayscale in brain diffusion-weighted magnetic resonance images (DWI) with acute ischemic stroke by using thalamic signal intensity on concurrent images (b0 image). In our computerized scheme, the gray level of b0 image was first normalized, and the brain region was segmented using thresholding and labeling techniques. The lateral inclination in b0 image was then corrected semi-automatically by rotating and shifting. Each of the thalamic positions was determined by using the coordinate information in the brain region. The average signal intensity of the thalamus was measured on the region of interest (ROI) selected, and the thalamus in one side with the low signal intensity was selected. The display grayscale in DWI was finally adjusted by using the signal intensity of the selected thalamus. The thalamus positions in all cases were confirmed to be included in the thalamic outline. In 30 training cases, the average error between the thalamic signal intensity obtained from the manual selection and the computerized scheme were 1.8%±1.5, and in 30 testing cases, 1.3%±1.2. Our computerized scheme has a potential in the determination of the display grayscale of brain DWI, and would be useful to radiologists in decision-making for radiological diagnosis.
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Special Issue Letter
<Biomedical Engineering>
  • Yasuhiro Ogoshi, Akio Nakai, Yoshinori Mitsuhashi, Chikahiro Araki
    2010 Volume 130 Issue 3 Pages 458-459
    Published: March 01, 2010
    Released: March 01, 2010
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    For a speech therapist, the breathing method is one of the important techniques to train a person who has difficulty in speaking. Insufficient number of therapists makes it difficult to apply these breath training methods widely. Therefore, development of a new breath training method will be mandatory. With this reason, a new training system is developed and described in this paper. In this new method, expiration pattern of a speech therapist analyzing through an air flow sensor is constructed into visual graphic image in order to recognize expiration pattern easily. With experimental use of this system to without handicapped trainees, they could successfully imitate trainer's pronunciation easily. A person who has difficulty in speaking will be able to learn easily how to do expiration for speaking through visual pattern.
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Paper
<Biomedical Engineering>
  • Kengo Kondo, Makoto Yamakawa, Tsuyoshi Shiina
    2010 Volume 130 Issue 3 Pages 460-467
    Published: March 01, 2010
    Released: March 01, 2010
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    For the purpose of diagnosing ischemic heart disease by detection of malfunction area and cancer tumor by detection of hard area, 3-D tissue motion must be correctly evaluated. So far various methods of measuring multidimensional displacement have been developed. Most of present techniques are restricted to one-dimensional measurement of tissue displacement such as myocardial stain-rate imaging. Although lateral modulation method enables us to attain high-accuracy measurement of lateral displacement as well as axial direction by generating lateral oscillating RF signals, the method causes distorted RF far from center of aperture. As a result, the method is not suited to sector scan which is used for myocardial examination. We propose a method to solve the problem by using 2-D modulation with the virtual hyperbolic beam forming and detection of 2-D displacement vector. The feasibilities of the proposed method were evaluated by numerically simulating the left ventricle short-axis imaging of cylindrical myocardial model. The volume strain image obtained by the proposed method clearly depicted the hard infarction area where conventional multi-beam Doppler imaging could not.
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<Systems, Instrument, Control>
  • Yuji Hamada, Yoshitsugu Sawa, Yukio Goto, Hiroyuki Kumazawa
    2010 Volume 130 Issue 3 Pages 468-475
    Published: March 01, 2010
    Released: March 01, 2010
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    In ad-hoc network such as inter-vehicle communication (IVC) system, safety applications that vehicles broadcast the information such as car velocity, position and so on periodically are considered. In these applications, if there are many vehicles broadcast data in a communication area, congestion incurs a problem decreasing communication reliability. We propose autonomous distributed transmit power control method to keep high communication reliability. In this method, each vehicle controls its transmit power using feed back control. Furthermore, we design a communication protocol to realize the proposed method, and we evaluate the effectiveness of proposed method using computer simulation.
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<Media Information, User Interface>
  • Yuta Shimoe, Kazuhiko Hamamoto, Kiyoshi Nosu, Koji Ogawa
    2010 Volume 130 Issue 3 Pages 476-482
    Published: March 01, 2010
    Released: March 01, 2010
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    This paper describes the design guideline of webs that use avatars and pictograms to promote nonverbal communication smoothly in a virtual space. The shops for clothes, consumer electronic, and furniture are constructed in the virtual space. The web sites using the avatar and the pictogram for shopping were examined. To investigate the usability, three kinds of the web layered structures were examined. The screen layout evaluation by the eyeball movement measurement was also carried out.
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<Speech and Image Processing, Recognition>
  • Junpei Tsujino, Hiroaki Kudo, Tetsuya Matsumoto, Yoshinori Takeuchi, N ...
    2010 Volume 130 Issue 3 Pages 483-489
    Published: March 01, 2010
    Released: March 01, 2010
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    We perceive a contour on the boundary of the regions with the different properties. However, we can also perceive the contour when there is no such physical difference. We call such a contour a subjective contour. Some researches proposed the methods of generating inner contours of overlapping objects using the model for generating a subjective contour. In this study, we try to improve the degree of allowable overlapping by using the energy minimization and the combinatorial optimization. In the pairing process, we defined an energy terms based on the properties in which an object forms convex closure and its contour is smooth. The system selects the optimal pairs of vertices by the combinatorial optimization based on the energy function composed with the energy terms. We conducted experiments on images of leaves and show the proposed method can generate inner contours of overlapping objects with one or both ends hidden or in which the background can be seen, for which the conventional method can't easily generate inner contours.
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  • Satoru Nagatomo, Junichiro Hayashi, Seiji Hata
    2010 Volume 130 Issue 3 Pages 490-495
    Published: March 01, 2010
    Released: March 01, 2010
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    The accuracy of 3D measurement using stereo method depends strongly on the accuracy of calibration. But, it's very difficult to keep optical systems exactly the same with the calibration condition. For this reason, the measuring system that uses stereo method needs calibration work again and again. To solve this problem, we proposed “relative stereo method” so far. Relative stereo method shows an impressively high accuracy in relative distance, and has a good tolerance to calibration error. However, relative stereo method needs enough length between the camera and measuring objects, so relative stereo method has errors in close range measuring. Therefore, this paper presents a new 3D measurement method which solves the problem of relative stereo method and has a good tolerance to calibration error.
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<Information Processing, Software>
  • Yoshiyuki Anan, Toyoshiro Nakashima, Kazunori Iwata, Hiroshi Yonemitsu ...
    2010 Volume 130 Issue 3 Pages 496-502
    Published: March 01, 2010
    Released: March 01, 2010
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    In this paper, we propose an errors estimation model for embedded software development projects and implement a model visual tool for processing projects with upper and lower limits from estimated errors. The models are derived by multiple regression analysis, because this way is well known and easily used by developers. In addition, we perform evaluate to conform the models effectiveness.
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  • Satoshi Nishimura, Mutsuo Sano, Katsuo Ikeda
    2010 Volume 130 Issue 3 Pages 503-509
    Published: March 01, 2010
    Released: March 01, 2010
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    We propose and implement a new stackable filesystem to backup data on a network in realtime, and discuss the basic performance. Conventional mirroring technologies utilize the mirroring function on the device layer or need a special filesystem, the allocation of the disk and the specific format of the filesystem are needed, and so the filesystem allocation is fixed. Therefore, when a backup operation is required for new services, mirroring in the device layer or the special filesystem cannot be implemented. The proposed stackable filesystem realize the backup functions without changing the device and filesystem allocations by the VFS mechanism. So it enables the realtime network backup. Moreover, it advances the throughput of reading and writing by making the NFS system function invoked from the inside of the filesystem. We developed this filesystem, and evaluated the performance from the viewpoint of throughput, system call speed and CPU loads. The results show that there is no problem in the viewpoint of the performance compared with the conventional filesystem, and the throughput of the read and write of GMFS is 2.0 times faster than conventional mirroring filesystem.
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<Energy, Environment and Sustainability>
  • Kazuto Yukita, Takuya Ota, Koji Fujimoto, Yasuyuki Goto, Katuhiro Ichi ...
    2010 Volume 130 Issue 3 Pages 510-518
    Published: March 01, 2010
    Released: March 01, 2010
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    This paper proposes a method to improve the load frequency control in a power system with distributed generation (DG). DG is assumed to include photovoltaic generation, wind power generation, fuel cells and etc. In this paper, a simulation is performed using a microgrid model or island model that is composed of a storage system with either wind power generation or photovoltaic generation system as the DG.
    The effectiveness of load frequency control (LFC) using a storage system is examined using a power transmission simulator. The model for the experiment has been composed of inverter, battery, synchronous generator and load. Using this model, the comparison examination was done in respect of output setting control and the case in which the PI control was used. As a result, when the output set-point control using power demand estimation method is executed, the control characteristic is very excellent.
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Letter
<Softcomputing, Learning>
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