Lerkvaranyu, Somkiat

Preferred name

Alternative Name

Lerkvaranyu, S.

Main Affiliation

School of Engineering

somkiat.le@kmitl.ac.th

Now showing 1 - 10 of 21

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Automatic indexing system for atmospheric laser radar data
(2002-01-01)
Lerkvaranyu, S.
;
Miyanaga, Y.
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Dejhan, K.
;
Cheevasuvit, F.
;
Mizutani, K.
The purpose of this paper is to design a new method for an automatic indexing system with unsupervised conditions. In this paper, the method of a self-organizing clustering network is adopted. It is used to classify and index a large amount of real atmospheric laser radar data. Initially, the parameters of each cluster will start with random initial values and are adapted with the algorithm. In this paper, six groups are clustered from the given data. It is also shown that some of these indicate quite important atmospheric condition characteristics.
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Extremely Low-Power Fifth-Order Low-Pass Butterworth Filter
(2021-04-01)
Aupithak, Nattharinee
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Torteanchai, Usa
;
Burapattanasiri, Bancha
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Lerkvaranyu, Somkiat
;
Khateb, Fabian
A fifth-order Butterworth low-pass filter using multiple-input operational transconductance amplifiers (OTAs) is proposed in this paper. It is expressed that the number of OTAs that used for realizing fifth-order low-pass filter can be reduced using multiple-input OTA and results to decrease the power consumption and the active area. N-input OTA can be obtained using multiple-input bulk-driven quasi-floating gate technique. Subthreshold technique is used to achieve extremely low power consumption which can be applied to biomedical systems. The proposed topology is simulated using 0.18 standard CMOS process. Simulation results show that the proposed filter has a bandwidth located within 250 Hz, a power consumption of 41 nW and a dynamic range of 61 dB.
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TEC prediction with neural network for equatorial latitude station in Thailand
(2012-01-01)
Watthanasangmechai, Kornyanat
;
Supnithi, Pornchai
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Lerkvaranyu, Somkiat
;
Tsugawa, Takuya
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Nagatsuma, Tsutomu
This paper describes the neural network (NN) application for the prediction of the total electron content (TEC) over Chumphon, an equatorial latitude station in Thailand. The studied period is based on the available data during the low-solar-activity period from 2005 to 2009. The single hidden layer feed-forward network with a back propagation algorithm is applied in this work. The input space of the NN includes the day number, hour number and sunspot number. An analysis was made by comparing the TEC from the neural network prediction (NN TEC), the TEC from an observation (GPS TEC) and the TEC from the IRI-2007 model (IRI-2007 TEC). To obtain the optimum NN for the TEC prediction, the root-mean-square error (RMSE) is taken into account. In order to measure the effectiveness of the NN, the normalized RMSE of the NN TEC computed from the difference between the NN TEC and the GPS TEC is investigated. The RMSE, and normalized RMSE, comparisons for both the NN model and the IRI-2007 model are described. Even with the constraint of a limited amount of available data, the results show that the proposed NN can predict the GPS TEC quite well over the equatorial latitude station. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS).
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Current-Mode Universal First-Order Analog Filter Using CCCIIs
(2023-01-01)
Phatsornsiri, Punnavich
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Torteanchai, Usa
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Wongprommoon, Natapong
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Kumngern, Montree
;
Jongchanachavawat, Wirote
This paper presents a new current-mode first-order universal analog filter using current-controlled current conveyors (CCCIIs). The proposed circuit can realize first-order sections such as all-pass, low-pass, high-pass filters with both non-inverting and inverting transfer functions into single topology. The pole frequency of these filters can be controlled electronically. The output terminals possess high impedance level which is required for cascading of current-mode circuits. The proposed analog filter is verified using SPICE simulation. The CCCII has been simulated using the 0.18 µm CMOS technology with a supply voltage of 1.8 V. The simulation result can show that it agrees well with theory.
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Mixed-Mode Universal Filter Using Differential Difference Transconductance Amplifiers
(2022-01-01)
Suksaibul, Pichai
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Torteanchai, Usa
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Kumngern, Montree
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Jongchanachavawat, Wirote
;
Burapattanasiri, Bancha
This paper presents a new mixed-mode universal biquad filter based on differential difference transconductance amplifiers (DDTAs). This work will be expressed that many filtering functions with electronic control of the natural frequency can be obtained using DDTA-based circuit. The topology provides voltage-mode (VM), current-mode (CM), transimpedance-mode (TIM), transadmittance-mode (TAM) transfer functions into single topology and each transfer function offers five standard filtering functions. The performance of the proposed topology is carried out using PSPICE simulators based on 0.18 μm CMOS technology from TSMC. The simulation result shows that it can confirm the proposed topology.
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Electronically Tunable Differential Difference Current Conveyor Using OTAs
(2021-04-01)
Sukhawit, Chuthitep
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Burapattanasiri, Bancha
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Torteanchai, Usa
;
Lerkvaranyu, Somkiat
;
Knobnob, Boonying
This paper presents a new electronically tunable differential difference current conveyor (DDCC) using operational transconductance amplifiers (OTAs). Unlike conventional DDCC, the proposed DDCC offers current gain between z- and x-terminal that can be controlled electronically by bias currents. The DDCC-based OTA can be investigated both simulation and experiment tests. The proposed DDCC is used to implement a quadrature oscillator to confirm workability.
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The variation of critical frequency of E layer over Chumphon, Thailand
(2013-12-09)
Wongcharoen, Poramintra
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Kenpankho, Prasert
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Sepsirisuk, Kasemsuk
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Supnithi, Pornchai
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Noppanakeepong, Suthichai
In this research paper presents the observed critical frequency of E layer (foE) over Chumphon, Thailand which is located at nearly the magnetic equator (lat. 10.72° long. 99.37° dip. 3°) during September 2004 to August 2005. The foE is one of essential parameters in the International Reference Ionsphere (IRI) model. We investigate the variation of the observed foE by comparing to the Sun spot number, ionospheric index, and 10.7 cm. flux. Due to essentially of accurate IRI model can be used to applied in communication such as it may be implied tendency of phenomena in E layer effect on high frequency communication over Chumphon, Thailand. © 2013 IEEE.
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An Ultralow-Power 0.5-V MI-OTA-Based Universal Filter for Efficient Low-Frequency Signal Processing
(2026-01-01)
Kulej, Tomasz
;
Kumngern, Montree
;
Khateb, Fabian
;
Lerkvaranyu, Somkiat
This work introduces novel universal filters implemented using multiple-input operational transconductance amplifiers (MI-OTAs). The MI-OTA is specifically designed for a minimal 0.5-V supply, achieving nano-watt level power dissipation, which positions the design as highly viable for demanding ultralow-power systems. The architecture employs a subthreshold, multiple-input, bulk-driven MOS configuration. This design not only extends the operational input voltage range but concurrently ensures minimal voltage and power consumption. The primary filter topology utilizes five MI-OTAs and two grounded capacitors to concurrently deliver all five standard filtering responses—low-pass, high-pass, band-pass, band-stop, and all-pass filter—from a single, fixed circuit structure. By integrating a sixth MI-OTA, the architecture becomes reconfigurable for operation in both voltage-mode (VM) and transimpedance-mode (TIM). This versatility yields both non-inverting and inverting transfer functions for all five fundamental responses, resulting in a total of 20 distinct output functions. This multifunctionality and power efficiency make the proposed designs exceptionally well-suited for low-frequency applications, such as bio-signal processing and sophisticated sensor interfacing circuits. Furthermore, a key feature is that the filter's natural frequency is electronically tunable across all responses. The MI-OTA was designed and simulated in Cadence Virtuoso, utilizing the TSMC 65-nm (1P9M) CMOS process. The device occupies a modest silicon footprint of 125 μm × 92 μm. Simulation results confirm a power dissipation of 150 nW at a 177-Hz cutoff frequency under the 0.5-V supply. Post-layout simulations verified the expected circuit performance. Finally, experimental validation was conducted using a discrete-component MI-OTA-based circuit built with the LM13700, thereby confirming the filter's correct operation.
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Atmospheric boundary layer observation by ground-based lidar at KMITL, Thailand (13° N, 100° E)
(2001-01-01)
Lerkvaranyu, Somkiat
;
Dejhan, Kobchai
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Cheevasuvit, Fusak
;
Itabe, Toshikasu
;
Mizutani, Kohei
Tropospheric aerosols effects on climate in directly through various cloud formation, the lidar has been used to study the composition of many particles mixing in the atmosphere including to study the aerosol and cloud. Currently, it has many types of lidar systems depending on the purpose of measurements. In this report, the ground-based lidar system was established at King Mongkut's Institute of Technology Ladkrabang (KMITL), THAILAND to study and measure the aerosol in boundary layer and cirrus clouds in the tropopause region. The aerosol measurement is in the form of scattering ratio whereas the signal depolarization has been applied to identify layers of cirrus clouds. The lidar system consists of laser source (Nd:YAG) with second harmonic wavelength, 28 cm Schmidt-Cassegrain telescope, photomultiplier tube (PMT) and data acquisition system.
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Multiple-Input Multiple-Output Universal Filter Using DDTAs
(2022-01-01)
Suksaibul, Pichai
;
Torteanchai, Usa
;
Manman, Somsak
;
Jongchanachavawat, Wirote
;
Kumngern, Montree
This paper presents a multiple-input multiple-output universal biquadratic filter using differential difference transconductance amplifiers. The variant filtering responses can be obtained by appropriately applying input signals and appropriately choosing output terminals. The voltage-mode filter possesses both high-input and low-output impedances. The proposed filter provides five standard filtering responses. The natural frequency can be controlled electronically, and the quality factor can be controlled orthogonally. The performance of the proposed filter is confirmed using PSPICE simulation based on 0.18 µm CMOS technology from TSMC.
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Lerkvaranyu, Somkiat

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