Houngkamhang, Nongluck

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Integrated Innovative Technology

nongluck.ho@kmitl.ac.th

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Multi-Entropy Feature Extraction With LSTM Networks for Acoustic Emission-Based Railway Crack Localization
(2026-01-01)
Laon, Popphon
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Pourbunthidkul, Supavee
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Rattan, Praphaporn
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Sahavisit, Tanawit
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Suwansin, Wara
Railway infrastructure security is contingent upon the prompt identification of structural anomalies within steel tracks. This research establishes a framework that merges acoustic emission (AE) sensing with advanced machine learning for prompt fracture identification and location. To improve the quality of Raw AE signals, they are first cleaned using Kalman filtering to tackle environmental disturbances and ambiguous readings. The characteristics that arise from entropy comprising approximate entropy, Shannon entropy, and dimensional entropy are derived to delineate the temporal patterns of fracture-induced emissions. Density-based spatial clustering of applications with noise (DBSCAN) is applied to remove outliers during preprocessing. Long short-term memory (LSTM) networks classify crack locations into three anatomical regions: rail head, web, and foot. Experimental validation with 3,000 labeled AE signals (1,000 per class) under laboratory conditions, the full pipeline that integrates Kalman filtering, entropy features, DBSCAN, and an LSTM classifier attains an accuracy of 98.83%. With an entropy-based variant, the accuracy drops to 96.67%, confirming the incremental value of temporal denoising and outlier rejection. While using mel-frequency cepstral coefficient (MFCC) baseline achieves 97.67% accuracy, a deep neural network (DNN) trained on Kalman-filtered, entropy-based, and DBSCAN-processed inputs reaches 96.33% accuracy, underscoring the advantages of temporal modeling for AE. A GRU using the same Kalman-filtered, entropy-based, and DBSCAN-processed inputs, achieves 97.67% accuracy, but trails the LSTM overall. When deployed on actual railway lines with a mobile inspection platform, the system maintained robust performance, correctly identifying 84.67% of cracks at 3 km/h and 80.67% at 5 km/h. The LSTM configuration consistently outperformed all alternative approaches, including the entropy-only variant, MFCC-based method, DNN classifier, and GRU model. This confirms the LSTM’s enhanced capability to capture the temporal dynamics of AE signals, establishing it as the most effective framework for AE-based crack localization in railway structural health monitoring.
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Development of a Serological Dilution Microfluidic Chip for Immunoassay Applications
(2022-07-01)
Thienthong, Therdthai
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Juntasaro, Ekachai
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Khemthongcharoen, Numfon
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Sripumkhai, Witsaroot
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Houngkamhang, Nongluck
This work aims to develop a multiple dilution microfluidic chip that is capable of diluting the human serum by means of two-fold dilution for seven levels from 1:2 to 1:128 with phosphate-buffered saline (PBS) buffer. The dilution in this work is processed in parallel in order to reduce the accumulated errors that the standard pipetting technique generates in the micro-well plate. The serum and PBS buffer are precisely delivered to the micromixers by controlling their flow rates. The dilution is achieved by the passive mixing process for which the serpentine geometry is designed in order to continually generate the Dean vortices along the serpentine microchannel to effectively mix serum and PBS buffer in the microfluidic chip. The prototype of this multiple dilution microfluidic chip is fabricated by using polydimethylsiloxane (PDMS). The dilution-in-parallel capability of this prototype is validated by using the UV-vis absorption method. The results reveal that the measured values of the seven dilution ratios obtained are in good agreement with the exact values. Finally, this prototype is evaluated for serological MOG-IgG detection in order to verify the reliable operation of this multiple dilution microfluidic chip. The prototype can successfully detect MOG-IgG at all volume concentration ratios.
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Fabrication of Al/Au hybrid SERS substrate using laser engraving for rapid detection of melamine and its analogues by hand-held Raman spectrometer
(2024-05-01)
Wongwasuratthakul, Puwasit
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Aumpalop, Weerada
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Chakaja, Chaiwat
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Satapornchai, Pemika
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Eiamsamut, Ploypailin
Surface-enhanced Raman spectroscopy (SERS), combined with a handheld Raman spectrometer, was utilized for the rapid and highly sensitive detection of melamine and its analogues. The investigation focused on the hybrid micro-nano structures of SERS-active substrates, fabricated by laser engraving aluminum (Al) sheets and depositing gold (Au) nanoparticles using magnetron sputtering. The laser engraving frequency was varied to get optimum SERS substrate. The fabricated SERS substrates were tested with rhodamine 6G (R6G) to optimize the Raman signal and subsequently detect melamine and its analogues viz., cyanuric acid, ammeline, ammelide in milk samples. The results demonstrated that a laser frequency of 20 kHz was the optimal condition for fabricating a micro-nano Al template with a depth of 61.21 μm, providing the highest Raman signal for R6G. The limit of detection (LOD) for melamine in mild acid solution and milk samples were determined to be 1x10-5 M and 1x10-4 M, respectively. The laser-engraved Al sheet technique offers a cost-effective approach for SERS substrate fabrication. The integration of the Al/Au hybrid SERS substrate with a hand-held Raman spectrometer demonstrates significant potential for detecting melamine and its analogues in realistic environments.
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PMMA/High-k Self-assembled TiO2 /PMMA Multi-layer Gate Dielectric for P3HT Organic Field Effect Transistors
(2022-01-01)
Inpor, Kroekchai
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Houngkamhang, Nongluck
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Thanachayanont, Chanchana
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Prichanont, Seeroong
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Kayunkid, Navaphun
In this work, a multi-layer structure of poly (methyl methacrylate)/ titanium dioxide/poly (methyl methacrylate) (PMMA/TiO₂ /PMMA; PTP) was proposed as a top-gate insulator for P3HT-based organic field-effect transistors (OFETs). Adding a TiO₂ interlayer as a high dielectric constant (high-k) material into PMMA film enables the modification of the dielectric constant of the multi-layers PTP film. The content of TiO₂ in the PTP film, which can be varied by changing the number of soaking cycles in TiO₂ solution, plays a crucial rule in modifying the dielectric constant of the PTP film. The higher the TiO₂ content used in the PTP film, the higher the dielectric constant of PTP film can be obtained. However, using high TiO₂ content led to a reduction in the dielectric constant of the PTP film due to leakage current induced by the agglomeration of TiO₂. The utilization of the top-gate insulator containing TiO₂ significantly enhanced several P3HT-OFETs characteristics, e.g., an increase in the I<inf>on</inf>/I<inf>off</inf> ratio, and a decrease in the threshold voltage. However, the use of the PTP top-gate insulator with a high content of TiO₂ resulted in regressions in the OFETs characteristics, such as a decrease in carrier mobility and reduction in the I<inf>on</inf>/I<inf>off</inf> ratio. OFETs operating at the optimum conditions of the PTP gate-insulator, with PTP thickness of 225 nm and RMS roughness of 20.0 nm, provided a dielectric constant of 7.13, a threshold voltage of-8.49 V, a saturation mobility of 2.2× 10-4 cm²V-1s-1, I<inf>on</inf>/I<inf>off</inf> ratio of 37.9, and a subthreshold slope of 0.39 V/decade.
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A Contactless Edge-AI Prototype for Simulated Apnea-like Respiratory Suppression and Motion Artifact Detection Using 60 GHz FMCW Radar
(2026-07-01)
Pairoch, Sathit
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Phasukkit, Pattarapong
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Houngkamhang, Nongluck
Sleep-related respiratory disturbances are difficult to monitor continuously outside specialized laboratories because conventional polysomnography is resource-intensive and intrusive. This study presents a contactless edge-AI engineering prototype for detecting controlled voluntary respiratory-motion suppression and motion artifacts using a 60 GHz frequency-modulated continuous-wave radar. The system integrates a 60 GHz radar front end, lightweight local preprocessing, an INT8 one-dimensional convolutional neural network deployed on the Analog Devices MAX78000 CNN accelerator (Analog Devices Thailand, Chon Buri, Thailand), and an event-driven Raspberry Pi Zero 2W gateway for alert transmission. Evaluation was performed using a controlled healthy-volunteer dataset consisting of normal breathing, voluntary breath-holding-induced respiratory suppression, and deliberate motion artifact. The final valid test set contained 270 technically valid 30 s windows balanced across the three classes. The INT8 model achieved an overall accuracy of 92.6% (95% confidence interval: 88.8–95.2%), with a macro-averaged precision, recall, and F1-score of 92.6%, 92.6%, and 92.5%, respectively. Active CNN inference on the MAX78000 consumed 0.152 ± 0.011 mJ and was completed in 5.20 ± 0.11 ms, corresponding to approximately 280-fold lower active inference energy than Python 3.14.6/TensorFlow Lite 2.21.0-based execution on the Raspberry Pi Zero 2W. These results demonstrate the feasibility of privacy-aware, low-power respiratory-pattern classification at the edge. However, the study should be interpreted strictly as an engineering proof-of-concept based on controlled voluntary breathing and movement tasks in healthy volunteers. It is not a clinically validated apnea or obstructive sleep apnea detection system and did not include polysomnography, oxygen saturation measurement, airflow sensing, sleep staging, or diagnosed patient cohorts.
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Demonstration of light absorption and light scattering using smartphones
(2020-01-01)
Malisorn, Khemchira
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Wicharn, Surawut
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Plaipichit, Suwan
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Pipatpanukul, Chinnawut
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Houngkamhang, Nongluck
This paper demonstrates the use of smartphones in an experiment of light absorption and light scattering. The LED display and camera of the smartphone are used as the light source and as the detector, respectively. The color wheel is used to choose the color of the light source to be shone through the sample for analysis. The detector directly measures the intensity of the light that passes through the sample to study light absorption according to the Beer-Lambert law. On the other hand, to investigate the light scattering, the detector orthogonally measures the intensity of the scattered light from the sample. The results of the light absorption correspond to the Beer-Lambert law. The scattered light from the sample is be measured by a smartphone. The experiment is easy to set up, without the need for any further expensive apparatus. We expect that this experiment will be useful for physics teachers to demonstrate light absorption and light scattering in the classroom or in a physics laboratory.
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Mixing-performance evaluation of a multiple dilution microfluidic chip for a human serum dilution process
(2021-09-30)
Thienthong, Therdthai
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Juntasaro, Ekachai
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Sripumkhai, Witsaroot
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Houngkamhang, Nongluck
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Chanasakulniyom, Mayuree
This paper is aimed to propose a numerically designed multiple dilution microfluidic chip that can simultaneously deliver several serum dilutions in parallel. The passive mixing scheme is selected for dilution and achieved by the serpentine mixing channel in which Dean vortices are induced to increase the contact area and time for better diffusion. The mixing performance at the exit of this dilution chip is numerically evaluated using five commonly-used mixing indices with the goal that the homogeneity of the mixture over the exit cross-sectional area of the mixing channel must be greater than 93.319% to fulfill the six-sigma quality control.
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Application of printable antibody ink for solid-phase immobilization of ABO antibody using photoactive hydrogel for surface plasmon resonance imaging
(2020-10-01)
Shrestha, Binit
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Pipatpanukul, Chinnawut
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Houngkamhang, Nongluck
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Brandstetter, Thomas
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Rühe, Jürgen
Biochips for multiplex blood typing through surface plasmon resonance imaging (SPRi) readout have been previously reported based on arrays of red blood cell (RBC) specific ABO antibodies (Abs). Although conventional surfaces, such as CM-dextran, are robust and highly specific, they are time and labor intensive to generate and functionalize. This work investigates the fabrication parameters and performance of printable ink consisting of a photoactive hydrogel precursor and antibody mixture for the fabrication of SPRi array biochip. The solid-phase immobilization of commercially available murine IgM ABO Abs on a SPR sensor chip with a multiplex detection of ABO antigens present on the surface membrane of human RBCs is reported. A quick and simple solid phase immobilization of protein on a SPR sensor chip was attained using the photocrosslinking polymer and microarray printing platform. A high density immobilized probes is obtained which allows high sensitivity, specificity, and surface regeneration. A signal to noise ratio of 22:1 and 25:1 at 5% and 10% immobilized-Ab respectively, is obtained with 5% RBC concentration. The sensor surface can be successfully regenerated for repeated use using DI water. Without loss of function, the Ab-printed chips could be stored up to 3 weeks at 4 °C.
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Frame-Level Accident Recognition via Detection Confidence Aggregation: A Cross-Domain Validation Framework for Thai Roadway Surveillance
(2026-07-01)
Gabbualoy, Somprasonk
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Phasukkit, Pattarapong
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Houngkamhang, Nongluck
Real-time roadway surveillance now leans hard on automated detection. How a model trained in one geographic context actually behaves on another, though, is still underexplored for Southeast Asian deployments. We answer that question for Thai roadway closed-circuit television with a cross-domain validation framework. A YOLOv11n (Ultralytics v8.2.0; Ultralytics, Los Angeles, CA, USA) detector trained with focal loss feeds a confidence-aggregation step that turns per-detection scores into a per-frame accident score, and we put four aggregation operators head-to-head. Reliability comes from DeLong variance estimation paired with non-parametric bootstrap on 1245 Thai frames that carry 23 positive accident events. Under maximum-class aggregation the proposed configuration reaches a frame-level AUROC of 0.959 ± 0.020 across three random seeds. Under top-K aggregation it reaches 0.965 ± 0.018. Per-seed DeLong 95 percent intervals exclude chance performance throughout. We also evaluate three baseline configurations: YOLOv5su comes in at 0.738, YOLOv8n at 0.868, and a Chiang Mai-tuned YOLOv11n variant at 0.918. The architectural progression seen on standard benchmarks therefore carries cleanly into the cross-domain setting. The same Chiang Mai-tuned variant reached an in-domain mAP50 of 0.952 yet only 0.918 cross-region AUROC on a separate Thai region, which is a quiet but clear signal that geographic proximity within a country does not on its own remove distributional shift. Bounding-box localisation appears as a secondary diagnostic because the operational target here is frame-level alerting rather than pixel-precise annotation. Edge deployment optimisation falls outside the present scope. What the work leaves behind is a reproducible baseline and a statistical protocol that follow-up Southeast Asian roadway-safety research can build on.
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A simple and high -performance immobilization technique of membrane protein from crude cell lysate sample for a membrane-based immunoassay application
(2023-01-01)
Khemthongcharoen, Numfon
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Uawithya, Panapat
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Yookong, Nutthapon
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Chanasakulniyom, Mayuree
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Jeamsaksiri, Wutthinan
Membrane proteins are difficult to be extracted and to be coated on the substrate of the immunoassay reaction chamber because of their hydrophobicity. Traditional method to prepare membrane protein sample requires many steps of protein extraction and purification that may lead to protein structure deformation and protein dysfunction. This work proposes a simple technique to prepare and immobilize the membrane protein suspended in an unprocessed crude cell lysate sample. Membrane fractions in crude cell lysate were incorporated with the large unilamellar vesicle (LUV) that was mainly composed of POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) before coating in the polystyrene plate by passive adsorption technique. Immunofluorescence staining and the Enzyme-Linked Immunosorbent Assay (ELISA) examination of a strictly conformation-dependent integral membrane protein, Myelin Oligodendrocyte Glycoprotein (MOG), demonstrate that LUV incorporated cell lysate sample obviously promotes MOG protein immobilization in the microplate well. With LUV incorporation, the dose–response curve of the MOG transfected cell lysate coating plate can be 2–9 times differentiated from that of the untransfected cell lysate coating plate. The LUV incorporated MOG transfected cell lysate can be efficiently coated in the microplate without carbonate/bicarbonate coating buffer assistance.

Houngkamhang, Nongluck

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