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Robust and real-time 3D reconstruction with quaternary & octonary gray code fringe projection profilometry and AI-based noise suppression
No full textFringe Projection Profilometry (FPP) was an established technique for non-contact 3D surface reconstruction. This research investigated advancements in FPP, focusing on enhancing both acquisition speed and reconstruction quality. Specifically, the study explored the implementation of higher-base Gray Code (GC) unwrapping methods and the application of Artificial intelligence (AI) for image enhancement.
Octonary Gray Code (OGC) and the Nero AI filter were combined to successfully achieve OGC unwrapping, a task previously considered infeasible. To accelerate acquisition, Quaternary Gray Code (QGC) and Octonary Gray Code (OGC) unwrapping techniques were evaluated, aiming to reduce the number of projected patterns. Real-time object capture was conducted using QGC, and processing efficiency was optimized through algorithmic refinement and Graphical Processing Unit (GPU) acceleration. This optimization resulted in a significant reduction in processing time, achieving an 87.6% decrease from 13.52 seconds to 1.68 seconds for 100 cycles.
Furthermore, the study examined the application of AI-driven image enhancement to improve reconstruction quality. Several AI models, including the Residual Dense Swin Transformer Network (RDSTN), OpenVINO Enhanced Deep Super-Resolution Network (EDSR), Nero AI Image Denoiser, and Canva AI Photo Enhancer, were compared for noise suppression and resolution enhancement. Results demonstrated substantial improvements in both metrics. Notably, the Nero AI Image Denoiser exhibited superior performance, achieving a 93.7% reduction in unwrapping noise, from a maximum absolute error of 200.9 radians to 12.6 radians. This method also preserved finer object details compared to conventional median filtering, which often compromised edge and depth information during noise reduction. In conclusion, this research demonstrated the efficacy of employing higher-base GC and AI-based image processing to significantly enhance the speed and accuracy of FPP, presenting a more robust and efficient 3D reconstruction methodology.Bachelor's degre
Dude, get vaxxed: take a shot against HPV
No full textDude, Get Vaxxed: Take a Shot against HPV is a public health communication campaign that aims to raise awareness about HPV among males aged 21-26 in Singapore, and increase behavioural intention to get vaccinated. Despite its prevalence and severity, HPV in males is greatly overlooked, with past HPV campaigns being largely female-centric. Through literature review, the study identifies a lack of existing HPV routine screening for males and serious health risks such as genital warts and certain cancers in men. Locally, there is also a lack of government initiatives and subsidies for males to get vaccinated. Formative research through (1) a quantitative pre-campaign survey, (2) expert interviews, and (3) focus group discussions uncovered a general lack of awareness of HPV among males in Singapore. Our campaign set out to (1) increase HPV awareness and (2) increase behavioural intent for HPV vaccination. Using a bold, relatable, social-first approach, combined with offline activations, the campaign successfully garnered 50,028 social engagements and $52,950 in PR value. The campaign successfully increased HPV awareness by 60% and a 54% increase in behaviour intention of getting vaccinated, and 1,213 attendees across our activations, with 133 vaccination pledges and 9 vaccine sign-ups within the campaign period. A parliament question was also filed to explore establishing gender-neutral subsidised vaccinations in Singapore. The insights from the campaign can be used to guide future HPV campaigns and drive action towards better public health outcomes.Bachelor's degre
Art in an unending present: depression and ekphrasis in Sara Baume’s A line made by walking
No full textIn the first chapter of Sara Baume’s A Line Made by Walking (2017), the protagonist, Frankie, expresses her frustration with the homogeneous representation of cancer and depression on television, with only one exception, the millionaire speaker, who describes his bodily and perceptual sufferings in a kind of poetic manner that Frankie finds unexpectedly genuine and original. Like him, Frankie is dedicated to using a unique way to speak the complex feelings of being deeply afflicted by depression. This paper examines how the artistic technique of ekphrasis is employed in the novel to offer a new perspective on expressing her own depressive experiences.Nanyang Technological UniversityThis conference paper was supported by NTU Interdisciplinary Graduate Programm
Deep learning methods for classification of respiratory infectious diseases using infrared spectroscopy data
No full textIn 2019, the SARS-CoV-2 viruses caused the worldwide coronavirus disease (COVID-19) which led to a large number of infected people and also the deaths, meanwhile the global economy suffers a severe downturn due to the spread and adverse effects of COVID-19. To better combat the spread of COVID-19, medical agencies require a faster method to accurately distinguish between positive and negative pharyngeal swab samples for diagnosing coronavirus infections. ATR-FTIR spectroscopy is employed to acquire infrared spectral signals from positive and negative nasopharyngeal swabs, which are then classified using a deep learning model. A new classification method is proposed, based on deep learning models and feature selection and transformation techniques. This method also demonstrates strong performance when tested on FTIR spectral data of positive and negative samples, achieving high mean accuracy, sensitivity, and specificity over 5-fold cross-validation. For the primary spectral data used, the initial CNN model achieves an accuracy of 81.4%, a sensitivity of 71.7%, and a specificity of 90.2%. A
significant performance improvement is observed when using the Chi-square-Test-PLS-CNN model, which achieves better results with an accuracy of 92.5%, a sensitivity of 86.5%, and a specificity of 97.7%. To further enhance classification performance, an early-stopping strategy is applied, leading to the best performance achieved by the improved Chi-square-Test-PLS-CNN model, with an accuracy of 95.6%, a sensitivity of 93.0%, and a specificity of 97.9%.Master's degre
Single-molecule quantification of photoredox activities and dynamics at the nanoscale on multifaceted 2D materials
No full textTwo-dimensional bismuth oxybromide (BiOBr) with multiple facets has been widely used in photocatalytic pollutant degradation and clean energy production. Herein, we used in situ single-molecule fluorescence microscopy to quantify structure-specific photoredox activities of facet-dependent BiOBr. The nanometric-mapping of photoredox reactions (resolution: 20 nm) clearly unveils the catalytic heterogeneity on {001} facet-dominant and {010} facet-dominant BiOBr, respectively (BiOBr-001 and BiOBr-010). The corners of BiOBr nanoplates exhibit the highest photoredox activities, followed by edges and basal planes, which are attributed to the unsaturated coordination sites in corners and edges. BiOBr-001 corners show the photoreduction and photo-oxidation activities of 108.0 ± 11.5 and 654.5 ± 83.2 s−1 mm−2, respectively, which are 1.2 and 3.4 times those of BiOBr-010 corners. Other structures of BiOBr-001 also exhibit superior reactivity to BiOBr-010. Such phenomena are ascribed to shorter charge transfer distance and the existence of high-index facets in BiOBr-001. Bulk activity evaluation further supports the single-molecule analysis. The investigation of temporal activity fluctuation reveals surface restructuring probably accounts for the activity enhancement at the nanoscale under practical reaction conditions. Hence, our study correlates the catalyst structure and reaction dynamics at nanometer resolution, which guides the performance improvement at both single-molecule and ensemble levels.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)Submitted/Accepted versionWe acknowledge the financial support from the Ministry of Education, Singapore, under its Academic Research Fund Tier 1 (No. RG60/21, RG1/23), and the Singapore Agency for Science, Technology and Research (A*STAR) AME YIRG grant (no. A2084c0065) and MTC IRG grant (no. M21K2c0110)
Houseboys and amahs: transformations and continuities in colonial domesticity, 1900–1950
No full textThis thesis examines the historical transformations within Singapore’s domestic service industry and the colonial home in the first half of the nineteenth century. The historiography of domestic servants in Singapore has charted a narrative of decline and displacement of Chinese male domestic servants during the 1920s to the 1930s. This was set against a central “servant problem” of increasing Chinese politicisation from 1912, which drove male servants out of the service to be replaced by female servants. This research re-examines and challenges this argument in new ways, with a stress on seeking continuity within transformation. It proposes to explore shifting political concerns, rather than consider Chinese politicisation as fixed, thus locating the “servant problem” within the different contexts of master-servant legislation (1910s), the gendered familial household (1920s–1930s), and the political aftermath of the Japanese Occupation (1941–1950). This thesis demonstrates that underlying such shifts in domestic labour structures are powerful continuities, especially seen with how male servitude transformed in new ways during the 1940s yet stayed remarkably stable. This crucially contests the narratives of decline and suggests a rethinking of our domestic servant histories within that central framework of tracing continuity within transformation.Bachelor's degre
Modulation of coacervate coarsening in liquid-liquid phase separation (LLPS)
No full textFrom the Humboldt squid beak proteins, pH responsive self-coacervating peptides were developed as a novel drug delivery system. These peptides are capable of sequestering and releasing cargos, hinting at their biomedical applications. While coacervates are readily internalised by cells, coacervates generally have a hydrodynamic diameter in the range of micrometres. To enable passive targeting of tumours using coacervates requires the understanding of factors affecting coacervate size. In this study, dynamic light scattering (DLS) was used to determine the effect of molecular crowders, bovine serum albumin (BSA) and tocopherol glycerol succinate (TPGS), on GW26 coacervate size, with and without sequestered proteins. Time dependency studies were conducted to understand GW26 coacervate stability over time. Finally, cellular uptake of size modified, protein sequestered GW26 was conducted, showing little effect of coacervate size on GW26 uptake. These results improved our understanding of coacervate size control, enabling potential use as a passively targeting drug delivery system via enhanced permeation and retention effect.Bachelor's degre
Breaking linear scaling relationships in oxygen evolution via dynamic structural regulation of active sites
No full textThe universal linear scaling relationships between the adsorption energies of reactive intermediates limit the performance of catalysts in multi-step catalytic reactions. Here, we show how these scaling relationships can be circumvented in electrochemical oxygen evolution reaction by dynamic structural regulation of active sites. We construct a model Ni-Fe2 molecular catalyst via in situ electrochemical activation, which is able to deliver a notable intrinsic oxygen evolution reaction activity. Theoretical calculations and electrokinetic studies reveal that the dynamic evolution of Ni-adsorbate coordination driven by intramolecular proton transfer can effectively alter the electronic structure of the adjacent Fe active centre during the catalytic cycle. This dynamic dual-site cooperation simultaneously lowers the free energy change associated with O-H bond cleavage and O-O bond formation, thereby disrupting the inherent scaling relationship in oxygen evolution reaction. The present study not only advances the development of molecular water oxidation catalysts, but also provides an unconventional paradigm for breaking the linear scaling relationships in multi-intermediates involved catalysis.Published versionThis work was financially supported by a grant (No. CHI-P2022-04) from Centre for Hydrogen Innovations at National University of Singapore. B.L. acknowledges support from the City University of Hong Kong startup fund (No. 9020003), ITF–RTH - Global STEM Professorship (No. 9446006), and JC STEM Lab of Advanced CO2 Upcycling (No. 9228005). Y.-G.W. acknowledges financial support from the National Natural Science Foundation of China (No. 22022504), NSFC Center for Single-Atom Catalysis (No. 22388102), the Guangdong “Pearl River” Talent Plan (No. 2019QN01L353), and the Science, Technology and Innovation Commission of Shenzhen Municipality (No. JCYJ20210324103608023). X.Z. acknowledges the National Key R&D Program of China (No. 2024YFE0109200)
Optimizing the thiosulfate-mediated zerovalent iron/persulfate activation systems: trade-off between Fe(III)/Fe(II) cycling and quenching effects in environmental remediation
No full textThe remediation of organic-contaminated water is a critical environmental challenge, and iron-based persulfate (PS) activation processes have emerged as a promising solution. However, the introduction of reductive sulfur species, while accelerating the Fe(III)/Fe(II) redox cycle, may also quench reactive species, potentially compromising the efficiency of Fenton-like systems. Here we systematically investigate the trade-off between accelerated Fe(III)/Fe(II) cycling and quenching effects in the zerovalent iron/PS (ZVI/PS) system using thiosulfate (TSF) as an activator. Our results show that low-level TSF (0.03-1.00 mmol/L) effectively facilitated the removal of naphthalene (Nap) and atrazine (ATZ), respectively. This enhancement is attributed to accelerated ZVI dissolution and FeSx formation, which promote the Fe(III)/Fe(II) cycle, with Fe(IV) was identified as the primary active species. However, high-level TSF (>1.0 mmol/L) drastically reduced Nap removal due to PS consumption and active species elimination. The optimal TSF dosage of 0.20 mmol/L (TSF/PS molar ratio of 1:10) demonstrated robust organic pollutant degradation, achieving a 22-fold increase in the rate constant (kobs) for Nap removal and 0.47-7.5-fold increases for ATZ removal. These findings highlight the potential of the TSF-ZVI/PS system as a versatile and efficient solution for degrading a wide range of organic pollutants, including PAHs and herbicides, in water treatment applications.Submitted/Accepted versionThis study was supported by Jiangxi Provincial Key Laboratory of Environmental Pollution Control (No. 2023SSY02011), the Natural Science Foundation of Jiangxi Province (No. 20242BAB20108 and 20212BAB203026) and Key Research and Development Program of Jiangxi Province (20232BBG70010)
Stable and highly emissive infrared Yb-doped perovskite quantum cutters engineered by machine learning
No full textQuantum cutting (QC) is an appealing energy conversion process wherein a single high-energy photon is transformed into two lower-energy photons. This process holds great promise in enabling applications in low-energy illumination and quantum communications .1, 2
Yb doping is an effective possibility to achieve QC in perovskite nanocrystals (NCs) thanks to the favored Yb3+ cooperation and the ionic nature of perovskites.3-5 However, currently, all Yb-doped perovskite quantum cutters are capped with conventional highly-dynamic binding oelylamine (OAm) and oleic acid (OA) ligands pair, which suffer from severe stability problems and hinder their potential applications in optoelectronics and communications.6
Recently, zwitterionic molecules, that carry both cation and anion functional groups, have shown great potential in preserving structural integrity as well as excellent quantum efficiency of perovskite NCs due to the multiple-functional groups chelating effect and eliminated proton exchange process.7-9 However, few works have been reported on the Yb doped perovskite NCs with strong binding zwitterionic type ligands. Developing an in-situ synthesis method with stronger binding ligands is pressing for perovskite quantum cutters.
Here, we present the first demonstration of achieving a high NIR PLQY close to the QC limit alongside exceptional stability in Yb-doped perovskite NCs. We developed an in-situ phosphine oxide synthesis route to prepare robust and highly efficient Yb doped perovskite CsPbCl3 NCs through zwitterionic type 3-(N,N-Dimethylpalmitylammonio)propanesulfonate (ASC-16) ligands. Tri-n-octylphosphine oxide (TOPO) was employed to assist the dissolution of YbCl3·6H2O precursor, which plays a critical role for effective Yb doping.
Moreover, we replaced the traditional trial-and-error approach involving time- and labor-intensive experimentation using Bayesian Optimization (BO) to optimize for NIR photoluminescence quantum yield (PLQY) through QC process. Across only 2 iterations of the active learning process, we were able to rapidly discover NCs with ultrahigh NIR PLQY close to QC limit (~192±5%), which is one of the highest for Yb doped perovskite NCs ever reported. Due to the strong coordination between zwitterionic ligands and NCs’ surface revealed by density functional theory (DFT) calculations, the prepared Yb doped CsPbCl3 perovskite NCs exhibits greatly improved stability under high UV laser flux, continuous annealing, and also long-term colloidal storage stability even at Singapore’s humid environment (at least three months). Our work not only provides an in-depth understanding of the surface modification of doped NCs, but also facilitates efforts to study the fundamental physics behind QC and NIR quantum communications