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Demonstrating MAST: an efficient system for point cloud data analytics
No full textThe rapid growth of point cloud (PC) data calls for specialized solutions for data management and analytics. In this paper, we introduce MAST, a prototype system designed for efficient PC data analysis. MAST enables users to perform analytical queries efficiently, incorporating semantic and spatial predicates while ensuring high query accuracy. In this demonstration, we introduce the framework of the system prototype, including the storage layer, preprocessing layer, query processing layer, visualization and user feedback layer. We introduce the user interface of MAST and its workflow, and showcase the end-to-end usage of the MAST system with 2 analytical queries executed on a real PC dataset.Published versio
Protocol for efficient generation of human artery and vein endothelial cells from pluripotent stem cells
No full textBlood vessels permeate all organs and execute myriad roles in health and disease. Here, we present a protocol to efficiently generate human artery and vein endothelial cells (ECs) from pluripotent stem cells within 3-4 days of differentiation. We delineate how to seed human pluripotent stem cells and sequentially differentiate them into primitive streak, lateral mesoderm, and either artery or vein ECs. We differentiate stem cells in defined, serum-free culture media in monolayers, without feeder cells or genetic manipulations.Ministry of Education (MOE)Published versionThis work was supported by NIH Director’s Early Independence Award DP5OD024558 (K.M.L.), NIH R01HL128503 (K.R.-H.), NIH R01HL169787 (E.S.), JDRF Northern California Center of Excellence (K.M.L.), Additional Ventures Innovation Fund (K.M.L.), Additional Ventures Expansion Award (K.M.L. and L.T.A.), Stanford Ludwig Center for Cancer Stem Cell Research and Medicine (K.M.L.), Stanford Beckman Center for Molecular and Genetic Medicine (K.M.L.), ARPA-H HEART 1AY1AX000002-01 (K.M.L.), Stanford Maternal and Child Health Research Institute Transdisciplinary Initiatives Program (K.M.L., L.T.A., and K.R.-H.), HHT Foundation (E.S.), Singapore Ministry of Education Academic Research Fund T2EP30122-0008 (C.C.), Lee Kong Chian School of Medicine Vascular Research Initiative (C.C.), California Institute for Regenerative Medicine TB1-01195 (A.T.N. and A.C.), Stanford School of Medicine Dean’s Postdoctoral Fellowship (Q.Y.), NIH T32GM007276 (Z.A.A.-U.), Stanford Sarafan ChEM-H Chemistry/Biology Interface Training Program (Z.A.A.-U.), and the anonymous, Fickel, and Weintz families (K.M.L.). S.L.Z. was supported by NSF and Stanford Graduate Fellowships and NIH T32GM007790. K.R.-H. is an HHMI Investigator. L.T.A. is a Siebel Investigator and Additional Ventures Catalyst to Independence Fellow. K.M.L. is a Human Frontier Science Program Young Investigator (RGY0069/2019), Packard Foundation Fellow, Pew Scholar, Baxter Foundation Faculty Scholar, and The Anthony DiGenova Endowed Faculty Scholar
Targeting FANCM by antisense oligonucleotides in ALT-positive cancers
No full textEffective therapies for cancers relying on the alternative lengthening of telomeres (ALT) mechanisms are still needed. Here, using CRISPR-Cas9 strategies, we validate FANCM (Fanconi anemia complementation group M) as a crucial target for ALT-associated cancers and demonstrate its importance in both in vitro and in vivo models. We further explore the use of antisense oligonucleotides (ASOs), specifically gapmers, to target FANCM mRNA. We designed and screened several gapmers, identifying effective candidates that potently reduced FANCM expression, which led to an increased ALT activity and telomeric dysfunction, concomitant with a reduced viability of ALT-positive cancer cells. Notably, gapmer 14, one of the identified ASOs, significantly impaired the viability of ALT cells and reduced tumor growth in an ALT-positive liposarcoma xenograft model, highlighting its therapeutic potential. These findings suggest that FANCM-targeting ASOs could represent a promising effective strategy for treating ALT-positive cancers.Ministry of Health (MOH)Nanyang Technological UniversityNational Medical Research Council (NMRC)Published versionThis work was funded or supported by: Singapore Ministry of Health’s National Medical Research Council (NMRC) (Open Fund—Young Individual Research Grant to M.J. [MOH-00534]), grants from Nanyang Technological University (NTU) to A.T.P., and the NTU PhD scholarship to N.L.B.Y
Chalcogenide metasurfaces enabling ultra-wideband detectors from visible to mid-infrared
No full textThermoelectric materials can be designed to support optical resonances across multiple spectral ranges to enable ultra-wideband photodetection. For instance, antimony telluride (Sb2Te3) chalcogenide exhibits interband plasmonic resonances in the visible range and Mie resonances in the mid-infrared (mid-IR) range, while simultaneously possessing large thermoelectric Seebeck coefficients of 178 µV K-1. However, chalcogenide metasurfaces for achieving miniaturized and wavelength-sensitive ultra-wideband detectors have not been explored so far, especially with a single material platform. In this paper, Sb2Te3 metasurface devices are designed and fabricated to achieve ≈97% resonant absorption for enabling photodetectors operating across an ultra-wideband spectrum, from visible to mid-IR. Furthermore, relying on linear polarization-sensitive Sb2Te3 metasurface, the thermoelectric photodetectors with linear polarization-selectivity are demonstrated. This work provides a potential platform toward the portable ultrawide band spectrometers without requiring cryogenic cooling, for environmental sensing applications.Published versionZ.D. and J.K.W.Y. would like to acknowledge the support from A*STAR AME IRG (Project No. A20E5c0093) and National Research Foundation (NRF) via Grant No.NRF-CRP30-2023-0003. In addition, Z.D. would like to acknowledge the funding support from the Agency for Science, Technology and Research (A*STAR) under its Career Development Award grant (Project No.C210112019), MTC IRG (Project No. M21K2c0116 and M22K2c0088), the Quantum Engineering Program 2.0 (Award No. NRF2021-QEP2-03-P09) and DELTA-Q 2.0 (Project No. C230917005). J.K.W.Y. would like to acknowledge the funding support from National Research Funding (NRF) Singapore NRF-CRP20-2017-0001 and NRF-NRFI06-2020-0005. Q.Y.S.W would like to acknowledge funding support from The National Research Foundation, Singapore under NRF-CRP (NRF-CRP26-2021-0004)
A Migrant's 'Femininomenon': examining perceptions and negotiations of gendered workplace dynamics by foreign domestic workers (FDWs) in Singapore
No full textSince the late 1970s, Singapore has growingly relied on the outsourcing of Foreign Domestic Workers (FDWs) to address the increasing “care deficit” in its reproductive sphere. Existing scholarship has largely focused on how Singapore’s legal policies––particularly, how the mandatory live-in arrangement and the exclusion of FDWs from the Employment Act––have exposed them to precarity, exploitation, and abuse by employers. However, beyond a policy-centric analysis, we contend that a gendered perspective is equally crucial in understanding the experiences of FDWs––specifically, how gendered considerations may shape the employer-employee dynamics, including employer-imposed ground rules and the interactions between FDWs and both male and female employers. Through in-depth semi-structured interviews with 19 FDWs, our thesis explores: (1) How do foreign domestic workers (FDWs) perceive workplace gender dynamics in Singapore?, and (2) How do FDWs navigate and negotiate gendered working dynamics?
Drawing on Bourdieu’s concept of habitus and Foucault’s concept of disciplinary power, our findings reveal that workplace dynamics in the household are deeply shaped by gendered considerations of both FDWs and their employers. These gendered dynamics, in turn, reconstruct FDWs as various identities of the familial unit––such as a child, a maternal figure, a prey, or a predator––each carrying distinct gendered motivations and implications on how FDWs are regulated. In response, FDWs develop strategies to navigate and negotiate these gendered dynamics, including avoidance, skill-building opportunities, and the reaffirmation of their femininity within and beyond the workplace.Bachelor's degre
LLM-enabled spatial query with examples
No full textEfficient spatial search is essential for modern information retrieval. Example-based approaches have emerged as alternatives to address the limitations of traditional search engines. This report introduces GeoGPT, an advanced example-based spatial search system enhanced by Large Language Models (LLMs) such as GPT-4 and Llama 2. GeoGPT overcomes the shortcomings of traditional approaches by leveraging LLMs to effectively interpret complex spatial relationships, refine nuanced user queries, and adapt to evolving user intents in real-time. To support robust user interactions, a graphbased data pipeline has been developed to generate synthetic data that closely mirrors real-world user behaviour. This enables precise fine-tuning of LLMs for spatial queries through techniques such as Parameter-Efficient Fine-Tuning (PEFT) and Instructional Tuning.
Additionally, GeoGPT features an intuitive user interface with interactive tutorials, intuitive dual-mode functionality, and a user-friendly map. This study lays the foundation for enhancing user experiences and expanding LLM applications in information retrieval across diverse domains.Bachelor's degre
A thesis on digital art market
No full textDigital art has been increasingly popular with the development of blockchain technology. Blockchain technology provides a form of protection for digital art sellers and buyers as it enables verifiable and tamper-proof records of ownership of digital artworks. In addition, it also records the information and transaction history of the artworks and allows public access to the information with exceptional transparency. Hence, it not only offers digital artists a new format to sell and promote their works but also allows researchers to observe the market activities. Thus, in this thesis, I focus on the subset of digital arts with information and transaction histories recorded on the blockchain.
A digital artwork/collectible (e.g., image, video, music) recorded on the blockchain is also called a non-fungible token (NFT). NFTs are becoming an increasingly popular form of art investment, with rocketed market growth in 2021. However, both consumers and sellers face uncertainty in the market activities. Consumers encounter uncertainty when making purchase decisions as there are no established valuation guidelines for NFTs. Sellers confront uncertainty when creating artwork owing to the lack of knowledge about consumer demand. Thus, this thesis investigates two different topics that surround uncertainty in the NFT market.
Chapter 1 examines herding behavior in NFT auctions and the moderating role of visual complexity and familiarity. Auction is one of the most popular selling formats in the NFT market. Given the valuation uncertainty for NFTs, consumers’ bidding tendencies would be influenced by other collectors’ bidding decisions (herding behavior). I build a model on bid continuation probability to capture the herding behavior in the primary auctions. In addition, the visual cues are essential in evaluating the artwork. In this regard, I examine how visual complexity and familiarity affect herding behavior, as these two visual characteristics usually affect both the ease of understanding and recognizing the visual stimulus. I use a computer vision technique to quantify the visual complexity of an NFT, and apply transfer learning to measure its visual familiarity. The findings show that there is herding behavior in NFT auctions, and visual complexity and familiarity both exhibit a U-shape moderating effect on herding tendency. This research further tests the subsequent impact of herding behavior in the primary auctions on the auction winners’ resale decisions. Results suggest that auction winners are more willing to resale the NFT and set a higher price premium when there is stronger herding behavior in the primary auctions. This research contributes to herding, NFT, and creative content production literature, and provides managerial implications for content creators and market platforms to promote sales.
Chapter 2 investigates how sellers can enhance revenue and benefit from introducing consumer uncertainty in product assignment (i.e., probabilistic selling). Probabilistic selling has become an increasingly popular and relevant phenomenon across industries, from traditional online travel agencies (e.g., probabilistic hotel rooms), retailing (e.g., clothing, and cosmetics subscription boxes) to digital gaming (e.g., in-game products), non-fungible tokens (NFTs), etc. However, despite the market prevalence, there is no empirical investigation into the actual benefit of marketers employing probabilistic selling to the best of our knowledge. Leveraging a feature change in an NFT marketplace, this research quantifies the effect of adopting probabilistic selling on sellers’ monthly revenue using three estimators (i.e., two-way fixed effect DiD, staggered DiD, and aggregate synthetic DiD). Results consistently show that probabilistic selling increases adopters’ monthly revenue within the range of 665.869. In addition, this research finds three underlying mechanisms that drive the revenue lift: protection provision on the transparent market, increased market thickness and matches, and enhanced market matching efficiency. At the same time, alternative mechanisms are discussed and ruled out. These findings add to the probabilistic selling, uncertain marketing and NFT literature. This research also provides managerial implications for sellers to increase sales and for market platforms to promote market participation and enhance market matching efficiency.Doctor of Philosoph
The stability improvements of dye-sensitized solar cell with natural template for photoanode using lignin extracted from rice husk
No full textIn response to escalating global concerns over environmental pollution, the development of green dye-sensitized solar cells (DSSCs) has emerged as a promising technology for solar energy conversion. This study harnesses the potential of rice husk, an abundant agricultural waste in Indonesia, by extracting lignin through a simple recycling method. Lignin acts as a natural, non-toxic dopant and template for TiO₂ composites, enhancing the stability of the photoanode in DSSCs. A TiO₂ photoanode modified with 5 % lignin achieved a power conversion efficiency (PCE) of 4.81 %. After a 90-day stability test, the TiO2/lignin 5 % composite retained 78 % of its initial PCE, significantly outperforming pristine TiO₂ in terms of short-circuit current density (JSC) and open-circuit voltage (VOC). This improved stability is attributed to increased porosity, better lignin dispersion within the TiO₂ matrix, prevention of agglomeration, enhanced surface area for dye adsorption, and reduced electrolyte leakage. Furthermore, lignin's high thermal stability on the TiO₂ surface provides additional protection against dye degradation and electrolyte evaporation during repeated light exposure.Published versionThe author (Gita Rabelsa) thanks BRIN Research Assistant (No. 60/II/HK/2023) and Degree by Research Program (No. 17/HK/II/ 2023). This research project was funded by Riset dan Inovasi untuk Indonesia Maju or RIIM program LPDP-BRIN (No. 82/II.7/HK/ 2022)
Room-temperature optically detected magnetic resonance of telecom single-photon emitters in GaN
No full textSolid-state defects susceptible of spin manipulation hold great promise for scalable quantum technology. To broaden their utility, operation at room temperature and emission in the telecom wavelength range are desired, eliminating cryogenic requirements and leveraging existing optical fiber infrastructure for the transmission of quantum information. To that end, we report that telecom single-photon emitters (SPEs) in gallium nitride (GaN) exhibit optically detected magnetic resonance (ODMR) at room temperature. The analysis of ODMR as a function of magnetic field orientation enables the determination of the orientation of the spin quantization axis with respect to the GaN crystalline lattice. The optical transitions dynamics are analyzed to gain further insight into the transition rates dominating ODMR. Our findings, coupled with the mature fabrication technology of GaNs, could facilitate the realization of scalable quantum technology.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)National Research Foundation (NRF)This work is supported by Singapore Quantum Engineering Program (NRF2021-QEP2-01-P01, NRF2021-QEP2-01-P02, NRF2022 QEP2-02-P13, NRF2021-QEP2-03-P10), Singapore Ministry of Education Tier 2 Grant (MOE-T2EP50221-0009, MOE-T2EP50222-0018), Agency of Science, Technology, and Research (A*STAR), Singapore, MTC IRG (Project No. M21K2c0116), and by the French government through the National Research Agency (ANR) Project No. ANR-22-CE47-0006-01.1 and in the context of the Plan France 2030 (ANR-22-PETQ-0011)
Single-stage multiport AC–DC–DC converter with reactive power control capability
No full textThis article introduces a single-stage three-port ac–dc–dc converter designed to overcome the limitations observed in conventional two-stage converters used in grid-tied applications with multiple dc sources, such as hybrid energy storage systems and microgrids. Traditional two-stage converters, typically comprising a dc–dc converter followed by a dc–ac inverter, are hindered by the multiple power conversion stages, an excess of components, and an insufficient number of dc ports. To address these issues, a single-stage three-port ac–dc–dc converter is proposed in this article. This converter serves as an interface among two dc ports and one ac port. The employed asymmetric PWM combined with dual-phase-shift modulation allows for the decoupling of reactive power control, bidirectional power transfer, and voltage gain regulation. Optimization efforts have been made to minimize the root mean square value of the leakage inductor current. Validation was achieved through experiments on a 1-kW prototype.Agency for Science, Technology and Research (A*STAR)Submitted/Accepted versionThis work was supported in part by A*STAR under its RIE2025 Manufacturing Trade and Connectivity (MTC) Industry Alignment Fund-Pre-Positioning (IAF-PP), under Award M23L5a0002, and in part by the Shenzhen Science and Technology Plan Project under Grant GJHZ20220913143008016