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Journal of Technology and Social Science (JTSS, J. Tech. Soc. Sci.)

An international open-access peer-reviewed journal

ISSN 2432-5686



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Home > Archives > Vol.4, No.2

Vol.4, No.2






Middle School Science Education Teaching Aids for Industry 4.0

Yuki Aoki, Takeshi Kase, Kenji Nakamura and Yasushi Yuminaka

Journal of Technology and Social Science, Vol.4, No.2, pp.1-6, 2020.

Abstract: This paper provides an overview of teaching aids the authors developed for middle school science classes using next-generation technology such as virtual reality, augmented reality, and a face-to-face learning management system. Our proposed aids have possibilities for the Internet of Things (IoT), big data (BD), and artificial intelligence (AI), all of which are necessary for the social realization of Industry 4.0.

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Single-Inductor Dual-Output Converters with PWM, Hysteretic, Soft Switching and Current Controls

Yifei Sun, Yasunori Kobori, Minh Tri Tran, Anna Kuwana and Haruo Kobayashi

Journal of Technology and Social Science, Vol.4, No.2, pp.7-32, 2020.

Abstract: This paper reviews some kinds of our investigated single-inductor dual-output (SIDO) DC-DC switching converters with PWM control, ripple-based hysteretic control and soft switching control. First, buck type SIDO converters with PWM control are explained with the exclusive control method. Second, hysteretic controlled SIDO converters with the triangular signal generated by the CR-circuit connected across the inductor, and third, soft-switching SIDO converters with the half/full wave type resonance and with ZVS-PWM resonant control, while last the current controlled converters are presented. The novel technologies of these SIDO converters are described with circuit topologies, operation principles, simulation results and experimental results. Also their comparison is discussed.

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EMI Reduction in Switching Converters with Pseudo Random Analog Noise

Yasunori Kobori, Yifei Sun, Minh Tri Tran, Anna Kuwana and Haruo Kobayashi

Journal of Technology and Social Science, Vol.4, No.2, pp.33-48, 2020.

Abstract: This paper proposes an EMI reduction method by extending spectrum spread using a PLL circuit and frequency modulation of a clock pulse with pseudo analog noise generated by a modified M-sequence circuit. The PLL circuit makes the reference clock to be modulated with non-periodic analog noise supplied from the 3-bit M-sequence circuit. Extended pseudo analog noise is produced by inverting and/or exhanging (swapping) 3-bit signals. Using this modified clock supplied from the PLL circuit for the saw-tooth signal in the switching converter, the spectrum of the PWM pulse is widely spread, and the peak levels of the spectrums of the fundamental frequency and the harmonic frequencies are substantially reduced.

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