Publication Showcase

Publication Showcase

Knowledge in Action
Dive into peer-reviewed publications and thought leadership shaping the frontiers of knowledge. This showcase connects you with the insights, data, and discoveries fueling innovation. Whether you’re a researcher staying current, an industry leader spotting trends, or a curious mind digging deeper — this is your portal to fresh thinking.

Draft Genome Sequence of Bacillus tropicus Strain UPM-CREST01, Isolated from the Bulk Paddy Soil at Kampung Gajah, Perak
We characterized the draft genome of the potentially beneficial Bacillus tropicus strain UPM-CREST01, which was isolated from the bulk soil at a paddy cultivation area in Kampung Gajah, Perak, Malaysia. The final draft assembly of 5,252,705 bp, with a G+C content of 35.23%, was found to harbor 5,368 coding sequences, including several plant-growth-promoting genes.
Correction of perspective distortion and intensity errors in projected fringe patterns in phase-measuring deflectometry
The relative pose between the projector and screen in a phase-measuring deflectometry (PMD) setup can result in perspective distortion and intensity errors in the projected fringe patterns. These problems degrade the sinusoidal characteristics of the fringe patterns, thus increasing phase, slope, and height errors in the PMD measurement. To overcome these issues, inverse perspective distortion and intensity modification algorithms were developed and applied to computer-generated fringe patterns before projection. The inverse perspective distortion matrices were obtained using a single image of the projected grid distortion target. The pixel intensities in the generated fringe patterns were modified using the relationship between the generated and captured pixel intensity values in grayscale images of uniform intensity. Experiments were conducted to measure the surface topographies of spherical concave and convex mirrors using a monoscopic PMD setup. Based on the experimental results, the root-mean-squared (RMS) intensity and phase errors in the projected sinusoidal fringe patterns were reduced by about 90% after using the modified fringe patterns compared to the original fringe patterns. When comparing the measured and the theoretical heightmaps, the results in PMD measurement showed an 8% and a 14% reduction of the RMS height errors in concave and convex heightmaps, respectively. The effectiveness of the algorithms in improving the accuracy of projector-based PMD measurement was demonstrated successfully.
Polynomial color compensation model with neural network solver for color-coded fringe patterns in phase-measuring deflectometry
The total image display/projection and image acquisition time in a projector-based phase-measuring deflectometry (PMD) measurement is reduced when color-coded fringe patterns are used since only a single image of the fringe pattern is sufficient to extract phase information using the phase-stepping method. This benefit is, however, offset by the difficulty in resolving various sources of color intensity errors of the fringe patterns in the camera view, such as uneven illumination, color imbalance, color crosstalk, and deviation of color intensity response of the camera and the projector from the calibrated color targets. Thus, a polynomial color compensation model is proposed in this study to compensate for color intensity errors. The model coefficients were estimated using the relationship between the captured and targeted color intensities, which are sequences of monochromatic 8-bit red, green, and blue (RGB) images for projection. The model was applied to modify the color intensities of the generated fringe patterns before projection. The modified color fringe patterns were then used for PMD measurement on spherical concave and convex mirrors. Based on the experimental results, the root-mean-squared (RMS) color intensity errors in R, G, and B channels were reduced by 33.3%, 58.3%, and 36.4%, respectively, after conducting the polynomial color compensation. The RMS phase errors in the fringe patterns were reduced by 71.9%. The RMS height errors and the radius percentage errors of the reconstructed concave and convex heightmaps were 1.87 μm (0.12%) and 1.55 μm (0.17%), respectively. The performance of the proposed polynomial color compensation model in reducing color intensity errors of the captured fringe patterns for accurate PMD measurement was demonstrated successfully.
Evaluations of Low-cost Air Quality Sensors for Particulate Matter (PM2.5) under Indoor and Outdoor Conditions
Air quality (AQ) monitoring is crucial for maintaining human health and well-being, whether outdoors or indoors. Particulate matter (PM) is among the most critical parameters that must be routinely monitored. Traditional reference particulate analyzers are expensive and difficult to deploy on a large scale, leading to poor spatial and temporal AQ information. However, the reliability and accuracy of these sensors are yet to be established. This study is aimed at assessing the performance of five low-cost sensors by comparing them with a particulate reference analyzer for AQ monitoring in accordance with the United States Environmental Protection Agency (US EPA)-recommended guidelines. The sensors were tested for indoor and outdoor environments using simple linear regress
Elevation of secondary metabolites production through light-emitting diodes (LEDs) illumination in protocorm-like bodies (PLBs) of Dendrobium hybrid orchid rich in phytochemicals with therapeutic effects
Gas-chromatography-mass-spectrometry revealed the presence of various bioactive compounds with anticancer properties in protocorm-like-body (PLB) cultures of a Dendrobium hybrid orchid (Dendrobium Enopi x Dendrobium Pink Lady). Pre-illumination of red fluorescent light lessened the stimulating effects of light-emitting diodes (LEDs) on secondary metabolites production among in vitro PLB cultures, possibly due to habituation. The highest flavonoid content of 16.79 μmol/ g of fresh weight (FW) was achieved under blue-red (1:1) LED for PLBs pre-treated with white LED for more than 3 subculture cycles. Phenolics content significantly reduced as PLBs pre-cultured under red fluorescent light for 2 subculture cycles were exposed to LED illuminations, where far red LED resulted in the lowest total phenolic content (18.85 μmol/ g FW). High intensity green LED (16.9 μmol/s) enhanced the accumulation of phenolics while amino acids such as L-leucine, glycine and proline exhibited no significant stimulating effect for secondary metabolites production.
A Subthreshold Operation Series-Parallel Charge Pump Incorporating Dynamic Source-Fed Oscillator for Wide-Input-Voltage Energy Harvesting Application
This work proposes a CMOS reconfigurable charge pump (CP) for a low-voltage energy harvesting system. It utilizes the low effective resistance from the parallel CP to enhance its power conversion efficiency (PCE). The CP exhibits an adaptive configuration with different stages depending on the input voltage, changing its voltage conversion ratio (VCR) to limit the output voltage under 1.8-V. Additionally, this work develops a novel dynamic source-fed oscillator that modulates the oscillating frequency by utilizing a dynamic source for the ring-voltage controlled oscillator (RVCO). The independent source from the RVCO and the clock-generating units from the proposed technique permit the implementation of frequency modulation without affecting the clock amplitude. Fabricated in 65-nm CMOS
A Fully Integrated CMOS Tri-Band Ambient RF Energy Harvesting System for IoT Devices
This article presents a fully integrated tri-band RF energy harvesting system (RFEH) in 65-nm CMOS technology. The system is designed to harvest ambient RF energies at 900 MHz, 1.9 GHz, and 2.4 GHz through a tri-band impedance matching network (IMN), cross-coupled differential-drive (CCDD) rectifier, and an output voltage monitoring circuit to limit the rectified output voltage to 3.3 V. The system achieves a power conversion efficiency (PCE) of over 30 % across all three frequency bands with a peak of 42.8 %. Furthermore, the system exhibits a peak sensitivity of -20 dBm at an output DC voltage of 1
A Reconfigurable Hybrid RF Front-End Rectifier for Dynamic PCE Enhancement of Ambient RF Energy Harvesting Systems
This paper presents a reconfigurable hybrid Radio Frequency (RF) rectifier designed to efficiently convert AC RF power to DC voltages for an energy harvesting system. The proposed reconfigurable rectifier adopts the advantage of low conduction loss in the switch-connected rectifier and low reverse current loss in the diode-connection rectifier topology to enhance its power conversion efficiency (PCE). Capable of reconfiguring into different rectifier topologies, the proposed circuit can reconfigure into a switch-based cross-coupling differential drive (CCDD) at low input power and a diode-based hybrid rectifier at higher input power for a wide dynamic range operation. Designed and implemented on a CMOS 65 nm technology, the post-layout result records a peak PCE of 88.7% and a wide PCE dynamic range (PDR) of 16 dBm for PCE >40%. The proposed circuit also demonstrates a −21 dBm sensitivity output across a 1 MΩ output load.
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