Now showing 1 - 10 of 24
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Cybersecurity for Industrial Control Systems
    (2024-01-01)
    Chaiyasoonthorn, Sawatsakorn
    ;
    Mitatha, Somsak
    ;
    ; ;
    Sriudomsilp, Theeraporn
    Cyber Vision plays a vital role in promoting a collaborative workflow that enhances synergy between IT and OT, ensuring secure operational production. Partnering with Cisco (Thailand), this study aims to bolster cybersecurity measures in the oil and gas (O&G) industry to protect against external cyber threats. Researchers plan to use Cyber Vision for protocol analysis, intrusion detection, vulnerability assessment, and behavioral analysis, providing valuable insights into the industry's security stance. Adhering to IEC 62443 and NIST 800-82 standards, Cyber Vision ensures the continuous, resilient, and safe operation of industrial processes by maintaining constant visibility into Industrial Control Systems (ICS). It comes pre-integrated with top-tier security information and event management (SIEM) and security orchestration, automation, and response (SOAR) platforms.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Synthesis of electronically tunable multifunction biquad filter using voltage differencing differential input buffered amplifiers
    (2025-02-01)
    Bunrueangsak, Sirigul
    ;
    ; ; ;
    Biquad filters are commonly used in analog circuits for various purposes in signal processing and communication applications. We synthesize an analog active biquad filter with five types of voltage-mode filtering functions. The filter is synthesized using a parallel passive resistor-inductor-capacitor (RLC) network and unity-gain voltage differencing amplifier. A voltage differencing differential input buffered amplifier (VD-DIBA) is the main active component, and the biquad filter has a three-input single-output (TISO) topology. By replacing the passive inductor and resistor with VD-DIBA-based inductance and resistance simulators with a subtractor, the TISO voltage-mode versatile filter is obtained from two VD-DIBAs, one resistor, and two capacitors connected to the ground. The proposed filter can provide five types of voltage-mode filtering functions: inverting bandpass and lowpass responses as well as noninverting band-stop, high-pass, and all-pass responses. The all-pass filter requires no additional active components. The three input voltage nodes have high impedance, and a low-impedance output voltage node facilitates cascade connections without using additional voltage buffers. In addition, the natural frequency and quality factor can be electronically tuned. The quality factor is controlled without disturbing the passband gain and natural frequency. The proposed filter is simulated and verified experimentally in the Personal Simulation Program with Integrated Circuit Emphasis (PSPICE) and through laboratory tests employing VD-DIBAs implemented using commercially available components.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Single Active Element Based Electronically Controllable Capacitance Multiplier
    (2022-07-15) ;
    Huaihongthong, Pintira
    ;
    ; ;
    The realization of capacitance multiplier using the versatile active building block, namely voltage differencing differential difference amplifier (VDDDA) is presented in this paper. The realized capacitance multiplier is very simple consisting of one VDDDA, one MOS resistor (RM) and one grounded capacitor which is attractive for integration. The multiplication factor (KC) of the realized circuit can be electronically controlled via the bias current (IB) and control voltage (VC) without the need of any matching condition of active and passive element. Moreover, the multiplication factor can be adjusted to be more or less than one. The performances of the presented capacitance multiplier are verified through Pspice simulation using CMOS VDDDA in 0.18μm TSMC technology with ±0.9V power supplies. The multiplication factor is designed to be KC=2 by choosing VC=0.85V, IB=50μA and C=30 pF. The simulated multiplication factor is around 1.98. The simulated operational frequency range is around three decades (6.16 kHz-8.91MHz). The performances of the proposed circuit are also verified by the experiment using VDDDA implemented from the commercial ICs, AD830 and LM13700 with ±5V power supplies. The experiment is conducted under the same multiplication factor (KC=2) as the simulation by choosing RM=0.27 kω (1% passive resistor), IB=96.2μA and C=1nF. The experimental multiplication factor is around 2.06. The experimental operational frequency range is around three decades (1kHz-1.25MHz). By adjusting the bias current from 17.67μA to 400 μA, the experimental multiplication factor is controllable from 11.47 to 0.48. The percent deviation of the theoretical and experimental multiplication factor is lower than 5% when the value of bias current is greater than 39μA. These deviations stem from the effect of the parasitic capacitance and resistance in VDDDA. Moreover, the application example of the presented capacitance multiplier as the sinusoidal oscillator is presented. The performances of the presented oscillator verified via the experiment are well consistent with theoretical anticipation.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Single commercially available ic-based electronically controllable voltage-mode first-order multifunction filter with complete standard functions and low output impedance
    (2021-11-01) ;
    Buakhong, Unchittha
    ;
    ;
    Khateb, Fabian
    ;
    Sotner, Roman
    This paper presents the design of a voltage-mode three-input single-output multifunction first-order filter employing commercially available LT1228 IC for easy verification of the proposed circuit by laboratory measurements. The proposed filter is very simple, consisting of a single LT1228 as an active device with two resistors and one capacitor. The output voltage node is low impedance, resulting in an easy cascade-ability with other voltage-mode configurations. The proposed filter provides four filter responses: low-pass filter (LP), high-pass filter (HP), inverting all-pass filter (AP−), and non-inverting all-pass filter (AP+) in the same circuit configuration. The selection of output filter responses can be conducted without additional inverting or double gains, which is easy to be controlled by the digital method. The control of pole frequency and phase response can be conducted electronically through the bias current (I<inf>B</inf>). The matching condition during tuning the phase response with constant voltage gain is not required. Moreover, the pass-band voltage gain of the LP and HP functions can be controlled by adjusting the value of resistors without affecting the pole frequency and phase response. Additionally, the phase responses of the AP filters can be selected as both lagging or leading phase responses. The parasitic effects on the filtering performances were also analyzed and studied. The performances of the proposed filter were simulated and experimented with a ±5 V voltage supply. For the AP+ experimental result, the leading phase response for 1 kHz to 1 MHz frequency changed from 180 to 0 degrees. For the AP− experimental result, the lagging phase response for 1 kHz to 1 MHz frequency changed from 0 to −180 degrees. The design of the quadrature oscillator based on the proposed first-order filter is also included as an application example.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Multi-phase structure electrospun CNF@Ag/Mn/Bi/Fe composite nanofiber enhanced supercapacitor behavior
    (2025-02-15)
    Sinprachim, Tanayt
    ;
    Klompong, Narit
    ;
    Chanlek, Narong
    ;
    Kidkhunthod, Pinit
    ;
    Maensiri, Santi
    This study presents the development of carbon-based multiphase metal oxide nanocomposites (CNF@MO<inf>x</inf>; M = Ag, Mn, Bi, and Fe) incorporating silver, manganese, bismuth, and iron nanoparticles within polyacrylonitrile (PAN)-derived carbon nanofibers. These nanocomposites were fabricated via the electrospinning technique with metal oxide concentrations of 10, 20, and 40 %w. This was followed by annealing in an argon atmosphere. The resulting nanofibers exhibited diameters ranging from 559 to 830 nm, with embedded nanoparticles measuring from 9 to 21 nm. Comprehensive characterization revealed that the nanofibers possessed uniform morphology, high porosity, and robust thermal stability. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) confirmed the valence states of the metal oxides (Ag⁰, Bi³⁺, Mn²⁺, Mn³⁺, Fe²⁺, and Fe³⁺), which are integral to redox reactions and charge storage mechanisms. Among the fabricated composites, CNF@Ag/Mn/Bi/Fe-20 demonstrated the best electrochemical performance, achieving a specific capacitance of 156 F g<sup>−1</sup> at a scan rate of 2 mV s<sup>−1</sup> and outstanding cycling stability with a capacity retention of over 96 % after 1400 charge-discharge cycles. The synergistic combination of double-layer capacitance and pseudocapacitance mechanisms in these nanofibers represents a significant improvement over conventional electrode material. This study highlights CNF@Ag/Mn/Bi/Fe nanocomposites as highly promising candidates for advanced energy storage applications, particularly in supercapacitor technologies.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    A New Method to Synthesise the Sinusoidal Oscillator Based on Series Negative Resistance-Capacitance and its Implementation Using a Single Commercial IC, LT1228
    (2023-01-01)
    Kulapong, Worawut
    ;
    ; ;
    Sotner, Roman
    ;
    An alternative method for synthesising the sinusoidal oscillator based on series negative resistance-capacitance is presented in this paper. The proposed topology is constructed with the series negative resistance-capacitance circuit connected in parallel with a grounded resistor and capacitor. To validate the proposed method, a new grounded series negative resistance-capacitance simulator is also proposed as a subcircuit for synthesising the sinusoidal oscillator. The series negative resistance-capacitance simulator is based on a commercially available integrated circuit (IC), LT1228. The equivalent negative resistance and equivalent negative capacitance can be adjusted electronically using an external DC bias current. The sinusoidal oscillator that is synthesised using the proposed method consists of a single LT1228, two capacitors, and three resistors. The frequency and the condition of the oscillation are orthogonally adjusted. Also, the condition of oscillation is electronically controlled. The amplitude of the sinusoidal waveform is adjustable. In addition, the output voltage node of the proposed oscillator has a low impedance, which allows it to connect to other circuits without using an additional buffer. Both PSPICE simulation and experiment are used to validate the proposed circuits.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Enhancing ICT Literacy and Achievement: A TPACK-Based Blended Learning Model for Thai Business Administration Students
    (2024-05-01)
    Nantha, Cherisa
    ;
    Siripongdee, Kobchai
    ;
    ; ;
    The COVID-19 pandemic has heightened the need for 21st century skills, particularly computer and ICT literacy (CICT) in Thailand. This study aimed to develop a TPACK (Technological Pedagogical and Content Knowledge)-based blended learning model (BLM) to enhance CICT skills and academic performance among 179 Business Administration (BA) undergraduates in the 2022 academic year Computer and Information Applications course. Research instruments were designed and evaluated by experts. Over 18 weeks, qualitative and quantitative data were collected, with the qualitative data undergoing content analysis. Descriptive statistics were used to analyze quantitative data, comparing pretests, post-tests, and 2-week retests using a repeated measure ANOVA. One-sample t-tests were used to assess the model’s impact on CICT skills. The results showed a significant score improvement between tests, with the highest mean being seen in the 2-week retest. The BA-TPACK model significantly enhanced CICT skills, exceeding 80%. The students expressed high satisfaction, with the BA-TPACK model effectively enhancing CICT skills and academic achievement, recommending its integration into future computer and information courses. This study’s contribution lies in addressing the pressing need for CICT skills in the ‘new normal’. By developing and implementing a BLM grounded in the TPACK framework, this study not only enhances students’ CICT proficiency but also fills a crucial gap in the literature regarding effective pedagogical approaches to foster 21st century skills.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Feasibility of integrating small-scale liquefied natural gas (LNG) terminal with combined cycle power plant to reduce carbon emissions and costs for data centers
    (2025-06-01) ;
    Sukjai, Yanin
    ;
    Rajoo, Srithar
    ;
    ;
    Global data centers are projected to consume 2–3% of global electricity and contribute 8% of carbon emissions by 2030, driven by the rising demand for 5G. In Southeast Asia's tropical climate, cooling data centers presents a challenge, as power plant efficiency drops by 10–20% during summer, when ambient temperatures reach 35–40°C. This study introduces a novel system that integrates a small-scale liquefied natural gas (LNG) receiving terminal with a combined cycle power plant (CCPP) and a data center, designed specifically for tropical climates. The system harnesses LNG cold energy through three configurations: intermediate fluid vaporizer (IFV), Rankine cycle (RC), and direct expansion cycle (DEC), to optimize electricity generation and chilled water production. By reducing the gas turbine inlet temperature from 35°C to 22°C, the system boosts power output by 12.22% and thermal efficiency by 3.84%. Nighttime cooling supports a 3,048-rack data center, resulting in annual savings of $5.50 million and a reduction of 20,304 tons of CO₂ emissions. Switching to gas power plants during summer further increases savings to $7.75 million and cuts emissions by 29,104 tons. An economic analysis shows a payback period of 2.30 years and an internal rate of return (IRR) of 69%. This integrated approach offers an efficient, cost-effective, and environmentally sustainable solution for power generation and data center operation in hot climates.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Single VDDDA-Based Lossy Inductance Simulator for Application to Sinusoidal Oscillator
    (2023-01-01) ; ;
    Sotner, Roman
    ;
    This work presents the design of a new grounded lossy inductance simulator. The proposed circuit emulates an inductor in parallel with a negative resistor, making it applicable to the design of a sinusoidal oscillator. The proposed simulator comprises a voltage differencing differential difference amplifier (VDDDA), a resistor, and a grounded capacitor. The proposed active inductor necessitates no essential matching criteria for passive elements. The equivalent inductance and negative resistance can be controlled electronically. Moreover, the parallel RLC and negative resistance configuration-based sinusoidal oscillator is designed as an example of its application. The oscillation frequency and condition are adjusted orthogonally. The performance of the proposed simulator circuit and the sinusoidal oscillator is evaluated using Pspice simulation and experimentation with VDDDA built from ICs AD830 and LM13700. The simulation and experimental results validate the behavior of the theory.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Electronically Tunable TISO Voltage-Mode Universal Filter Using Two LT1228s
    (2022-01-01)
    Wai, May Phu Pwint
    ;
    ; ; ;
    This study aims to design an electronically tunable voltage-mode (VM) universal filter utilizing commercially available LT1228 integrated circuits (ICs) with three-input and single-output (TISO) configuration. With the procedure based on two integrator loop filtering structures, the proposed filter consists of two LT1228s, four resistors, and two grounded capacitors. It realizes five filter output responses: low-pass, all-pass, band-reject, band-pass, and high-pass functions. By selecting input voltage signals, each output responses can be achieved without changing the circuit architecture. The natural angular frequency can be controlled electronically. The input voltage nodes Vin1 and Vin3 possess high impedance. The output node has low impedance, so it can be cascaded to other circuits. The performance of the proposed filter is corroborated by PSpice simulation and hardware implementation which support the theoretical assumptions. The result shows that the range of total harmonic distortion (THD) is lower than 1%, and that the higher the temperature is, the lower the natural angular frequency is.