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Author: search.filters.author.Pirajnanchai, ViroteStart date: 2020

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    Lifespan Estimation of Closed-Circuit Television (CCTV) Systems Using Weibull Modeling
    (2026-02-01)
    Chutchavong, Vanvisa
    ;
    Pirajnanchai, Virote
    ;
    Doungpan, Satawat
    ;
    Kasettakarn, Witchapon
    ;
    Phungtua-eng, Thanapol
    Ensuring the availability and reliability of electronic components or materials during operation necessitates conducting a sampling inspection of their lifespan. This is particularly crucial when comparing equipment or materials deployed in various areas with diverse environments, conditions, and situations. Many studies rely on one-method parameter estimation methods, which fall short in identifying the two explicit parameters of the Weibull distribution. Moreover, inaccurate parameter estimation methods impede the attainment of reliable analysis results. Consequently, this paper introduces three analytical estimation methods to determine the parameters of the Weibull distribution. The accuracy of these methods is evaluated using the mean square error (MSE). Furthermore, we utlized the Kolmogorov–Smirnov and Anderson–Darling test on real datasets, confirming that the data follow a Weibull distribution. Simulation results indicate that the maximum likelihood estimate outperforms the other estimators by minimizing the MSE and yielding optimal parameters. These optimal parameters were then applied to real CCTV datasets, demonstrating a good fit and enabling assessment of CCTV lifespan through the mean time to failure, which is estimated to be 6.6 years. This holds true even when the equipment operates in environments with different conditions and situations.
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    Synthesis of Video Gain Equalizer via Distributed circuits
    (2025-01-01)
    Chutchavong, Vanvisa
    ;
    Pirajnanchai, Virote
    ;
    Rattanathanawan, Pongpan
    ;
    Ngammongkolwong, Sudasawan
    ;
    Puntapa, Vorawut
    This paper presents a linear luminance and chrominance gain equalizer in video waveform transmission. Practically, the distributed devices have physical characteristics similar to the transmission line. Therefore, it can be employed to function in approximately as a passive lumped element. For this purpose, a novel transformation can be realized on equalizer using commemorated passive and active filters with uniformly distributed URC lines. In this paper we introduce two types of gain equalizers. The first type consists of resistive, conductive and capacitive, known as uniform GCR elements. The second type approximated by the uniformly distributed RC transfer function. As the results the proposed gain equalizer prove in equalizing both the luminance and chrominance gain distortions correction. From the simulation results, it is shown that the proposed distributed circuit gives good amplitude chrominance characteristic for both types of luminance gain equalizers.
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    Design of Luminance-Chrominance Gain Equalizer Using Uniformly Distributed RC Circuits
    (2024-01-01)
    Chutchavong, Vanvisa
    ;
    Pirajnanchai, Virote
    ;
    Doungpan, Satawat
    ;
    Ngammongkolwong, Sudasawan
    ;
    Rattanathanawan, Pongpan
    The propose of this paper is to design the luminance-chrominance gain equalizer use in the video waveform transmission. As it is known, the conventional measurement and gain corrector of chrominance distortion equipment is not so simple. This network corrector has to use fillers and delay time to separate the luminance signal and chrominance signal by means of low-pass and high-pass filter in connection. Here in, we deploy the uniformly distributed RC circuit (URC). We introduce two types of equalizers. The first type is to correct the luminance signal without deteriorating the chrominance signal. The second type is designed to correct the chrominance signal with no effect to luminance signal. Both equalizers comprise of a few gain amplifiers and URC circuits. From the simulation results, it is shown that the frequency response of gain equalizer given good effective in correcting video signal distortion. We also introduce the modulated sine-squared pulse test signal for measuring and correcting the amount of low gain and high gain of the chrominance signal.
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    Synthesis of Crossover Network Using O′Shea′s Transformation via URC
    (2024-01-01)
    Janchitrapongvej, Kanok
    ;
    Chutchavong, Vanvisa
    ;
    Doungpan, Satawat
    ;
    Ngammongkolwong, Sudasawan
    ;
    Rattanathanawan, Pongpan
    This paper describes method of synthesis two-way cross-over network, namely low-pass filter and high-pass filter. Firstly, we introduce synthesis method of obtain all-pass filter. We introduce O′Shea′s transformation P(s) = cosh√SRC and Wyndrum′s transformation W(s) = tanh√SRC via uniformly distributed RC (URC) network. After obtaining a desired all-pass filter, as an elementary process. We construct low-pass filter and high-pass filter by means of all-pass filter basis. Simulation results MATLAB are carried out and stability are also investigated.