Wyniki wyszukiwania - BazTech

1

Study of Obstacles Effect on Mobile Network and WLAN Signal Strength

Radhakrishna Kavinesh S., Lee Y. S., You K. Y., Thiruvarasu K. M., Ng S. T.

International Journal of Electronics and Telecommunications

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2023

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Vol. 69, No. 1

155--161

EN

In the era of continuous advancement in wireless technologies, path loss, also known as channel attenuation, is a drop in signal strength from the transmitter to the receiver. Path loss modelling is critical in designing fixed and mobile communication systems for various applications. This paper focuses on the received power (dBm) and free space path loss (FSPL) on various distances and frequencies such as 5240 MHz for wireless local area network (WLAN) and frequency such as 2100 MHz for the mobile network such as Celcom. As a result, able to analyze the correspondence between received power (dBm) and distance of each related frequency and the correspondence between FSPL (dB) and distance of each corresponding frequency and able to analyze the effect of obstacle on received power (dBm) and frequency.

2

Investigate Bending Effect of Wearable GPS Patch Antenna with Denim and Polyester Fabric Substrate

Radhakrishna Kavinesh S., Shakhirul M. S., Lee Y. S., Khairina K. N., Syafiqah A. R. A.

International Journal of Electronics and Telecommunications

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2023

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Vol. 69, No. 2

225--231

EN

In high technologies today, wearable devices have become popular. Wearable technology is a body sensing system that supports application of health observance and tracking through a wearable Global Positioning System (GPS). The design of the patch antennas is highly significant for the brilliance of the wearable patch antennas. This paper focuses on analyzing the bending effect on return loss and frequency between three types of GPS patch antenna. Types of GPS patch antennas that have been designed in this project are with different substrates and different designs. The wearable patch antenna has been designed and analyse using CST software. As a result, able to analysis the reflection coefficient (S11), radiation patterns, and analytical approach for patch antenna bending effect were obtained.

3

Non-thermal plasmas induced electrostatic stress on corneocyte desquamation

Tiwari P. K., Lee Y. S.

Acta of Bioengineering and Biomechanics

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2013

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Vol. 15, no. 2

65--72

EN

The advent of non-thermal plasma brought a breakthrough in exploring its clinical applications in dermatology to bolster tissue generation in the domain of plasma medicine. This study aimed to investigate the effect of non-thermal plasma on the corneocyte of the skin cells, in treating superficial skin diseases via the process of corneocyte desquamation, a probable mechanism for skin cell proliferation. The postulated brick and mortar arrangement of corneocytes in the stratum corneum was modeled consisting of three corneocytes and three corneodesmosomes in a simulation domain of 40.30 × 3.00 μm2 using Maxwell 2D finite element analyzer. The corneocyte desquamation was quantified by the weakening of corneodesmosomes due to electrostatic pressure (~530 MV/m) on the corneodesmosome surface exceeding its tensile strength (~76 MPa). A mathematical model displaying a relationship between the plasma potential and the skin tensile strength is also presented in this investigation. The non-thermal plasma could emerge as a clean and dry therapy to treat superficial skin diseases. Our study propels investigating the interaction of non-thermal plasma with the wet tissue in the deeper layer (dermis) of the skin cells and also, the development of such instruments for a comprehensive skin treatment.

4

Reduced switching in randomized schemes for DC-DC power conversion

Sathiakumar S., Shrivastava Y., Lee Y.S.

Przegląd Elektrotechniczny

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2006

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R. 82, nr 2

123-127

EN

Random switching schemes for power conversion are expected to reduce annoying electromagnetic interference and acoustic noise caused by switching. This is achieved by spreading the spectrum of the switching waveforms in different random schemes reported in the literature and as a result the output characteristics of the converter are altered differently. A comparative study of random pulse width modulated schemes for DC-DC power converter is presented in this paper. The spectral performance of four random schemes for the DC-DC power conversion is studied and their relative merits and demerits are highlighted. A method to reduce the average switching frequency of the random schemes without significantly affecting the output characteristics of the converter is also proposed. The random schemes discussed as well as the proposed schemes are implemented using a laboratory setup with a buck converter driven by the DSP TMS320C240 and the experimental results are presented comparing the performance of different schemes.

PL

Zastosowanie algorytmów modulacji losowej dla przekształtników ma na celu zmniejszenie zakłóceń elektromagnetycznych, jak również szumu akustycznego spowodowanego przełączaniem. Uzyskiwane jest to dzięki rozmyciu widma fali PWM przy użyciu szeregu opisanych w literaturze schematów modulacji losowej. W artykule przedstawiono analizę porównawczą algorytmów losowej modulacji szerokości impulsów dla przekształtników DC-DC. Przestudiowano widma czterech schematów modulacji losowej oraz naświetlono ich wzajemne wady i zalety. Zaproponowano metodę zmniejszenia średniej częstotliwości przełączeń dla losowych modulacji bez znaczącego wpływu na charakterystyki wyjściowe przekształtnika. Algorytmy modulacji losowej jak również metody zaproponowane w artykule zostały zaimplementowane w układzie laboratoryjnym z przekształtnikiem obniżającym napięcie sterowanym za pomocą procesora DSP TMS320C240. Zaprezentowano wyniki badań eksperymentalnych porównujące osiągnięcia różnych algorytmów modulacji.