IEEJ Transactions on Fundamentals and Materials
Online ISSN : 1347-5533
Print ISSN : 0385-4205
ISSN-L : 0385-4205
Volume 139, Issue 11
Displaying 1-30 of 30 articles from this issue
Special Issue on Frontier of Education in Electrical and Electronic Engineering
Special Issue Paper
  • Hajime Miyauchi, Masako Sazanami
    2019 Volume 139 Issue 11 Pages 463-468
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    Recently, children no longer play outside. Therefore, the athletic ability of children has to declined. We have been doing a workshop to let children have interest in manufacturing and traditional culture continuously. In this study, we devised the active child program that increased the interest in play in addition to the workshop to achieve these aims. We tried two programs. The first one is the theme of Hachiman of the Iwami-kagura. Because of the ogre extermination story with a bow and arrows, it is an electronic craft work lesson including Sports Onigokko and archery game. The second one is four-frame manga. It is the creation of a short story using a matrix LED including a gesture game. In these workshops, we gave a stage of performance to express children's ideas. This is considered to be a logical communication training method including the element of directing.

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  • Tomomi Tanioka, Masayuki Yamauchi, Yoshihiro Masui, Tetsuji Taniguchi, ...
    2019 Volume 139 Issue 11 Pages 469-477
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    This paper examines the effect of our early education for undergraduate students majoring in electronics and computer engineering. In our department in Hiroshima Institute of Technology, we prepare Techno-club program for students who have no idea on how to study but are eager to learn something in their school lives. In the process of development for technology, engineers need to attend meetings, discuss matters, make presentations, and negotiate with people from various countries. It is necessary for engineers to have not only professional knowledge and technical skills but also communication abilities, the ability to think for themselves, and the skills to exchange their ideas to create something new with their colleagues. This program can work as one of the supporting project against a decline in academic standards and also help students find out what they want to do with their friends. Considering the results from first generation students had belonged to Techno-club and entered graduate school, reports on the institutional design, its practical results and comparative analysis are described.

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  • Takahiro Hoshino, Kohei Tomaru, Yuki Ota, Takafumi Komuro, Yoshio Hama ...
    2019 Volume 139 Issue 11 Pages 478-485
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    The new Courses of Study requires that education methods be improved based on active learning. The Courses of Study for science education note the importance of problem-based learning (PBL), in which students perform their own observations and experiments, for increasing students' interest in science. In this paper, we propose problem-based experiments (PBEs), which are educational experiments that adopt the philosophy of PBL to promote students' interest in physics. In PBEs, students formulate hypotheses on problems given by their teacher, and then they test their hypotheses through independent activities such as performing measurements and calculations. Students can consider better ways to solve the problems based on their initial results. To assess the effectiveness of PBEs, we used support software to evaluate experiments on accelerated motion performed by high school students. According to the results of a comprehension test administered during the experiment, students had improved understanding of basic concepts and laws related to energy. Additionally, the results of a questionnaire given after the experiment showed that the PBE increased the interest of over 75% of the students in physics.

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  • Yumiko Abe, Yukihiro Mashiko
    2019 Volume 139 Issue 11 Pages 486-491
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    Synchronized computer mediated communication (SCMC) tools such as text chat and video conference have been used commonly for daily communication in the field of language learning in recent years as technology has increased opportunities for their use. We examined how each application may affect language production by non-native English speakers (NNs) in terms of exchange and interaction. We also examined whether learners expressed different attitudes in each mode of online communication. We used a reciprocal peer review system with an E-voting activity module in Moodle in the context of English learning in international collaborative learning. We paired Philippine and Japanese students of English in text chat and video chat modes of Computer-Supported Collaborative Learning (CSCL). The results suggest that the use of these tools, both text and video, increased the sense of closeness between peer partners. The results show that “fun” was more highly evaluated by the Philippine learners for both modes, whereas the Japanese learners evaluated fun higher in text chat groups. The results of this study also suggest that the Philippine English learners promoted communication with Japanese learners of English, and thus mutual understanding between them deepened.

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  • Minoru Komatsu, Takashi Matsumoto
    2019 Volume 139 Issue 11 Pages 492-497
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    We devised a practice to work in a virtual company on electrical technologies in order to acquire the fundamental competencies for working persons. In this paper, we show the contents of innovation practice on electrical technologies and describe the verification. The constructed practice can be widely applied in education.

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  • Sachiko Morita, Tatsuya Furukawa, Hisao Fukumoto, Masashi Ohchi
    2019 Volume 139 Issue 11 Pages 498-506
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    In our laboratory, a job hunting support system for students has been designed and implemented. The system has many functions that support various aspects of job hunting activities. As a part of the system, we have designed and improved the “Web Based Reception System for Milk Round”. The proposed system helps teachers and students share accurate information about companies, which is very important for job hunting. In this paper, first we have illustrated the conventional reception system for milk round, then we have augmented an E-mail function into the conventional system newly and improved the usability for students using Microsoft Access.

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  • Yuto Misaka, Sachiko Morita, Hisao Fukumoto, Tatsuya Furukawa, Masashi ...
    2019 Volume 139 Issue 11 Pages 507-513
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    It is important to provide the information about job hunting for students at universities. One of the methods to provide the information is to hold joint information exchange meetings for job hunting. When faculties hold meetings, they have to prepare layout sheets to show organizations' booth positions. Spreadsheet programs are usually used to create layout sheets. However, if the number of organizations participating in the meeting increases, it hasn't only taken more time but also made more mistakes to create them. In this study, the authors have developed the system for allocating organizations' booth positions and creating layout sheets based on the organizations' data registered on the web page by using database. Moreover, we have added some functions in order to edit layouts freely and send e-mails. As a result, faculties could correctly create layout sheets in a short time and the workload for preparations has been decreased. This system will be expanded to the creation of other layout sheets.

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  • Hisao Fukumoto, Tatsuya Furukawa, Masashi Ohchi
    2019 Volume 139 Issue 11 Pages 514-520
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    In recent years, the students studying electrical engineering tend to have lower interest in the fields related to electrical machinery and electric power than that in fields such as AI, robotics, and information technologies. On the other hand, the use of renewable energy such as solar power and wind power is rapidly spreading, and an advanced control technology is needed for the electric power system. Therefore, the next generation electric power system called as smart grid or micro grid have greatly attracted attention. It is very important to train engineer familiar with these new electric power systems. The authors have developed a learning support system that can be learned by remote experiment using ICT for the Energy Management System (EMS). This paper describes learning tasks and experimental tasks in the developed system. In addition, we confirmed the educational effects of the developed system.

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Special Issue Technical Note
  • Masaaki Yoshida, Takanobu Maeda, Susumu Nakamura
    2019 Volume 139 Issue 11 Pages 521-525
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    This paper describes the attempt to train electric and electronic system teachers at 3 Mongolian colleges of technology. Most of the teachers teaching specialized subjects at these schools, have not had practical experience doing experiments, so the classes they taught were lecture style, not hands-on style. Moreover, although they studied technology and graduated from domestic universities, they had no experience writing reports detailing experiments, or writing graduate studies. Therefore, they could not understand Kosen's Japanese education style at all, but they hoped to obtain a deeper understanding, as well as acquire teaching skills like those of Japanese Kosen teachers. To satisfy their request, we carried out a teacher training program utilizing our advanced course students. We hope this trial will be a useful opportunity to spread Kosen's education system throughout the world.

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Special Issue on Instrumentation and Measurement Technology for Creating Technological Innovation 2019
Special Issue Paper
  • Takuya Ueda, Katsutoshi Saeki, Jyunichi Neguchi, Takeshi Ohgo, Takehir ...
    2019 Volume 139 Issue 11 Pages 527-532
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    In recent years, in order to prevent conflicts between heavy machinery and people, development of a system using supersonic sensing with high reception feeling and direction controllable has been performed. In the past, we investigated directional control of ultrasonic waves using a multilayer main reflector and a concavo-convex curve sub-reflector. In this paper, we propose dual focal concavo-convex curve sub-reflector and a multilayer main reflector. As a result, the size was reduced by half compared with the conventional reflector, and the detection distance of 4 m or more became possible. It is clarified that directivity control is possible in the range of +38°, -34° to +50°, -58°.

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  • Satoshi Tsuji, Teruhiko Kohama
    2019 Volume 139 Issue 11 Pages 533-538
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    Smartwatch is one of useful wearable devices. However, the display of smartwatch is small, and the operability is low. A technique of around device interaction (ADI) has attracted attention. In this paper, we propose ToF sensor array on the curved surface to operate a smartwatch using user's back of the hand. The ToF sensor array detect the finger motion on the wide range of user's back of the hand because the sensor is on the curved surface. In addition, the sensor detects the multi-touch and palm motion. Thus, ToF sensor array on curved surface will be useful interface for smartwatch.

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  • Osamu Furukawa
    2019 Volume 139 Issue 11 Pages 539-544
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    Distributed optical fiber sensor based on a peak-frequency change of a spectrum of Brillouin scattering light has been extensively studied since it can measure strain and/or temperature in various applications. The distributed optical fiber sensor observes the spectrum of backscattered light from the specified section according to a spatial resolution and determines strain and/or temperature based on the peak-frequency change of the spectrum. However, the observed spectrum may have two maximum peaks that corresponds to strain and/or temperature included in the specified section of the optical fiber. Overlapped noise by the interrogator system to two peaks on the Brillouin gain spectrum causes false detection of the maximum peak-frequency. Although this false detection may occur, no workarounds has been discussed yet. This paper proposes a workaround by method of ‘peak tracking and trend analysis' that considers the change of peak intensity to determine peak frequency of the spectrum and confirms its effect of preventing false peak detection of Brillouin gain spectrum.

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  • Shouta Kanno, Takeshi Imaike, Akihito Otani
    2019 Volume 139 Issue 11 Pages 545-550
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    We study on a radio communication evaluation system with under-sampling. We show that a components of in-phase and quadrature can be corrected when a difference frequency between carrier signal and local oscillator is high. In addition, we show increasing noise with under-sampling when the difference frequency is higher than sampling frequency.

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  • Takashi Kawamura, Masaaki Fuse, Shigenori Mattori
    2019 Volume 139 Issue 11 Pages 551-557
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    We have proposed of a novel pre-selector for spectrum analyzer used over 100 GHz. This pre-selector is a filter bank embedded band pass filters in a waveguide switch part. Since this filter bank is composed of the waveguide switch, the performance of the waveguide switch decides on the using range of the filter bank. In particular, the broadband of the waveguide joint is needed. In this paper, we proposed expansion method of the frequency range in the waveguide joint with improved chokes. In addition, to confirm an effect of this expansion method, we fabricated and evaluated of the WR-4 band filter bank prototype. As a result, the prototype operated with a relative bandwidth 34% (185 GHz∼260 GHz).

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  • Daiki Yoshida, Tatsuya Furukawa, Hisao Fukumoto, Soudai Kawamura, Masa ...
    2019 Volume 139 Issue 11 Pages 558-564
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    These days, the smartgrid system is suggested as the next power network. The purpose of introducing the smartgrid is to make the power system high performance and environmentally friendly. It is essential to improve the reliability of transmission and distribution lines to achieve that. Then, the photovoltaics systems have been spread, however, it is concerned that the harmonics are generated by the inverter and deteriorate the quality of the power delivery system. The harmonics will be an obstacle to transformers, phase advanced condensers and so on designed in the commercial frequency. Therefore, it is necessary to measure the status of power lines at all times. The authors have designed and developed the small power status sensor for placing in pole switch and measuring power factor and harmonics. The proposed sensor measures voltage and current waveforms and sends the results with single-board computer, which is also put in pole switch, over the Internet. In this study, the authors describe the more downsized sensor's design using finite element method and experiment results with simulated power line.

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  • Taiyo Matsumura, Hiroki Seta, Takashi Ono, Satoru Takahashi, Akira Sum ...
    2019 Volume 139 Issue 11 Pages 565-572
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    In this paper, we proposed a method for automatic detection of urination based on the measurement results by the ultrasonic residual urine instrument. We also proposed a method to visualize the voiding pattern by an approximate curve. From this, while reducing the work burden of patients with lower urinary tract symptoms and assistants, it is possible to efficiently carry out the diagnosis of the doctor and the coordination of the urination care team and lead the patient in the direction of urination independence.

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  • Taiyo Matsumura, Kiyoyuki Kugenuma, Akito Eijima, Takashi Ono
    2019 Volume 139 Issue 11 Pages 573-578
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    We aim to establish an examination method that can determine the apnea condition. So far, we have conducted experiments simulating OSAS and CSAS, measured chest and abdomen amplitudes with a depth sensor, and overlaid each waveform to visually grasp the characteristics of OSAS and CSAS. However, it is difficult to determine the characteristics of SAS visually from the waveform, because the actual screening test of SAS takes a long time. In this paper, we propose a method to automatically detect OSAS and CSAS from measured chest and abdomen amplitude waveforms.

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  • Hayato Matsuura, Tota Mizuno, Kota Akehi, Marzieh Aliabadi Farahani, K ...
    2019 Volume 139 Issue 11 Pages 579-584
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    In this research, we proposed a new input method which improved the problem of conventional character input method in smart devices. In this system only the acceleration sensor of smart devices has been utilized. Also, it has a simple and distinctive wrist movement input method. We proposed four types of input operations which are divided depending on whether the operation speed is fast or slow. The average discrimination rate was 90% in case of fast and 70% in case of slow.

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  • Hiroto Seki, Takashi Izumi, Hiroyuki Hosono
    2019 Volume 139 Issue 11 Pages 585-595
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    The objective of this study is to reduce rear-end vehicle collisions caused by human errors. In order to achieve this objective, we studied a technique to detect preceding vehicles with image processing using a monocular in-vehicle camera and a computer. As an image characteristic for vehicle detection, we adopt the shadow underneath vehicle. Furthermore, in order to detect the shadow with high precision, we study shadow tracking. In this paper, we describe a technique for vehicle tracking on the basis of the shadow underneath vehicle.

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  • Shuji Sayama
    2019 Volume 139 Issue 11 Pages 596-602
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    In stormy weather due to typhoon approaching the Kanto district, I have observed sea clutter containing a target (ship) using an X-band radar with a frequency of 9.41GHz, a beamwidth of 1.0°, a pulsewidth of 0.5µs, and a pulse-repetition frequency of 1,600Hz. To estimate the sea clutter amplitude statistics, I have used partial Q-Q plot. The partial Q-Q plot is as follows : locate the maximum value on the histogram of observed data and find the point on Q-Q plot corresponding to the maximum value. Fit the approximate line to this point and the nearest ones on both sides by least squares method. Adding a neighbor point on the right side of these ones, fit it similarly, and then adding a neighbor point on the left side of these ones, fit it similarly. Repeat them and select the approximate line giving the smallest RMSE (Root Mean Square Error). I have found that the sea clutter amplitudes obey the log-Weibull distribution with the shape parameters of c=21.13 for entire data and c=17.80 to 32.26 for data within the beam width of an antenna. When sea clutter contains a target, it is found that the partial Q-Q plot is more rigorous fit of the distribution to the data than maximum log-likelihood method.

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  • Shuji Sayama
    2019 Volume 139 Issue 11 Pages 603-609
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    I have observed sea clutter containing a target (ship) using an X-band radar with a frequency of 9.41GHz, a beamwidth of 1.0°, a pulsewidth of 0.5µs, and a pulse-repetition frequency of 1,600Hz. To investigate the sea clutter amplitude statistics, I introduce the Akaike Information Criterion (AIC). I have found that the sea clutter amplitudes obey the Weibull distribution with the shape parameter of c=2.83 for entire data and the log-normal, Weibull, and log-Weibull distributions with the shape parameters of σ=0.439, c=2.76 to 4.59, and c=8.09 to 10.42, respectively, for data within the beam width of an antenna. The number of the smallest AIC (MAIC) of the log-normal, Weibull, and log-Weibull distributions to data are 1, 18, and 2, respectively, from 21 range sweep numbers. I have used a circuit to convert Weibull to Rayleigh distributions and a Cell-Averaging (CA) LOG/CFAR circuit. It is found that ship is detected and sea clutter is suppressed with improvement of 31.43dB by CFAR processing.

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  • Shuji Sayama
    2019 Volume 139 Issue 11 Pages 610-617
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    I have observed sea clutter containing a target (ship) using an S-band radar with a frequency of 3.05GHz, a beamwidth of 1.8°, a pulsewidth of 0.5µs, and a pulse-repetition frequency of 1,600Hz. To investigate the sea clutter amplitude statistics, I use partial Q-Q plot. I have found that the sea clutter amplitudes obey the Weibull distribution with the shape parameter of c=3.18 for entire data and the Weibull and log-Weibull distributions with the shape parameters of c=3.05 to 4.36 and c=11.84 to 11.95, respectively, for data within the beam width of an antenna. The number of the largest log-likelihood of the Weibull and log-Weibull distributions to data are 9 and 2, respectively, from 11 range sweep numbers. I have used the Weibull/CFAR (Constant False Alarm Rate) circuit which is modified a Cell-Averaging (CA) LIN/CFAR circuit. It is found that ship is detected and sea clutter is suppressed with improvement of 40.82dB by Weibull/CFAR.

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  • Shuji Sayama, Seishiro Ishii
    2019 Volume 139 Issue 11 Pages 618-624
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    We have observed sea clutter using an S-band radar with a frequency of 3.05GHz, a beamwidth of 1.8°, a pulsewidth of 0.5µs, and a pulse-repetition frequency of 1,600Hz. To estimate sea clutter amplitude statistics, We introduce new three-parameter log-Weibull distribution and the Minimum Description Length (MDL) principle. We have found that the sea clutter amplitude obey the three-parameter log-Weibull distribution with the shape parameter of c=24.42 for entire data and the log-normal, Weibull, log-Weibull, and three-parameter log-Weibull distributions with the shape parameters of σ=0.183 to 0.215, c=6.17 to 7.81, c=30.16 to 32.58, and c=21.20 to 87.31, respectively, for data within the beam width of an antenna. The number of best fit of the log-normal, Weibull, log-Weibull, and three-parameter log-Weibull distributions to data are 2, 4, 2, and 4, respectively, from 12 range sweep numbers. It is found that location parameter of the three-parameter log-Weibull distribution works effectively.

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  • Takeshi Imaike, Yuki Umezu
    2019 Volume 139 Issue 11 Pages 625-631
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    In this paper, we examined the phase noise residual effect of sampling clock in fully digital phase noise measurement. When measuring the phase noise of the oscillator, it is necessary to prepare a reference oscillator (REF) in addition to the DUT. Although the frequency of the DUT and REF is the same in the phase noise measurement using the conventional PLL, the frequency of the DUT and the REF is different because the PLL is not used in the fully digital phase noise measurement. In particular, it is clarified that fatal measurement error occurs when the frequency of the measured oscillator and the reference oscillator are different.

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Special Issue Letter
  • Shusuke Otake, Mana Kubota, Tota Mizuno, Hirotoshi Asano
    2019 Volume 139 Issue 11 Pages 632-633
    Published: November 01, 2019
    Released on J-STAGE: November 01, 2019
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    This research assesses the effect of autonomic nerve on wavelength bandwidth. In red light and blue light, broad wavelength band light becomes 4 times as wide as narrow wavelength band light. We regulate to impress as the same color between broad wavelength band and narrow wavelength band. Horizontal illuminance of their light is 17lx at subject’s eye. This experiment measures skin temperature and electrocardiogram as autonomic nerve indices. In red light, wavelength bandwidth affects sympathetic nerve and parasympathetic nerve. In blue light, wavelength bandwidth does not affect sympathetic nerve and affects the parasympathetic nerve. This result suggests the possibility that wavelength bandwidth affect autonomic nerve.

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