192815 research outputs found
Sort by
OptiNeRF: a spatially optimized neural rendering framework for complex scene reconstruction
No full textNeural rendering techniques aim to generate photorealistic images and accurate 3D geometries from multi-view images but often struggle with efficiency and geometric consistency in complex or dynamic scenes. Optimized Neural Radiance Fields (OptiNeRF) addresses these challenges through several innovations. It uses spatially optimized sampling to focus on points near object surfaces, reducing computation while improving precision. Leveraging the pre-trained Marigold model, it generates depth and normal maps as geometric priors. Sampled points are processed through a hybrid network combining an MLP and a multi-resolution feature grid (MRF), capturing fine details and large-scale structures. To handle varying illumination and complex materials, OptiNeRF introduces adaptive volume rendering (AVR), dynamically adjusting light transparency and scattering. A progressive sampling strategy further focuses computation on regions with high geometric complexity. The loss function incorporates RGB, normal, depth, boundary, and lighting optimization losses, with adaptive weight modulation for geometric priors, ensuring both visual fidelity and geometric consistency even with inaccurate depth/normal estimates. Experiments on dynamic scenes show strong performance, with a PSNR of 32.10 dB, SSIM of 0.936, Chamfer distance of 1.28 × 10−3, training time of 12 h, and rendering speed of 25 FPS, demonstrating high geometric accuracy, realistic rendering, and computational efficiency over conventional methods
Gender Differences in Self-Efficacy and Motivation in Online Peer Assessment
No full textOnline Student Peer Review (OSPR) is increasingly used in higher education to enhance engagement, reflection, and active learning. However, research on gender differences in OSPR remains limited, particularly regarding psychological factors such as self-efficacy and motivation. This study examines gender differences in these constructs during OSPR, with a secondary focus on a teacher-centered, gender-segregated educational context. 56 undergraduate computer science students (24 male, 32 female) participated in a structured, anonymous peer review task. Self-efficacy in evaluating and receiving feedback, along with intrinsic and extrinsic motivation, were measured using validated instruments. Results showed that female students reported significantly higher self-efficacy, particularly in evaluating peer work, while motivation did not differ significantly by gender. Across the sample, intrinsic motivation correlated moderately to strongly with all self-efficacy dimensions, particularly among females. For male students, extrinsic motivation was moderately associated with self-efficacy in receiving feedback. These findings suggest that well-designed OSPR activities can foster confidence and motivation, especially for female students in male-dominated disciplines like computer science. In teacher-centered environments, where feedback is top-down and student autonomy is limited, OSPR offers a valuable way to promote learner agency and engagement. The study contributes to the limited research on gender in OSPR and offers practical insights for designing inclusive online peer review activities in both mixed-gender and gender-segregated settings
FedQuad: Federated Stochastic Quadruplet Learning to Mitigate Data Heterogeneity
No full textFederated Learning (FL) provides decentralised
model training, which effectively tackles problems such as
distributed data and privacy preservation. However, the generalisation of global models frequently faces challenges from
data heterogeneity among clients. This challenge becomes even
more pronounced when datasets are limited in size and class
imbalance. To address data heterogeneity, we propose a novel
method, FedQuad, that explicitly optimises smaller intra-class
variance and larger inter-class variance across clients, thereby
decreasing the negative impact of model aggregation on the global
model over client representations. Our approach minimises the
distance between similar pairs while maximising the distance
between negative pairs, effectively disentangling client data in the
shared feature space. We evaluate our method on the CIFAR10 and CIFAR-100 datasets under various data distributions
and with many clients, demonstrating superior performance
compared to existing approaches. Furthermore, we provide a
detailed analysis of metric learning-based strategies within both
supervised and federated learning paradigms, highlighting their
efficacy in addressing representational learning challenges in
federated settings
The Dangerous Thrill of Destabilisation: Interview with Dr Jacob Engelberg on Cinemas of Bisexual Transgression
No full textSam Button interviews Dr Jacob Engelberg on his new book, Cinemas of Bisexual Transgression. The book argues that the way we look at queer film centres the gay/straight binary and considers what happens when bisexuality breaks the rules
Supporting understanding: comparing conversational interviewing in chatbot vs human-administered patient-reported outcomes for stroke survivors
Get PDFHospitals use patient-reported outcome measurements (PROMs) to monitor stroke survivors post-discharge. Unfortunately, PROM items are prone to misinterpretation. Human-administered PROMs mitigate comprehension issues through conversational interviewing (CI), in which facilitators provide real-time clarification. However, chatbots have not yet adopted CI techniques, raising questions about whether CI-enabled chatbots can effectively support PROM administration. We conducted a controlled experiment with 18 stroke survivors comparing two CI clarification techniques —1) additional examples and 2) reflective prompts —against 3) no clarification (control) administered by both a chatbot and a human facilitator. Our findings demonstrate the feasibility of CI-enabled chatbots, as participants’ responses remained consistent across facilitators and clarification types. Participants exhibited better PROM answer behaviour when using the chatbot, with fewer anecdotal digressions and greater adherence to validated response options. Notably, when receiving CI support, participants stopped asking the human facilitator for clarification. Preferences for clarification varied by question type: participants favoured examples for physical activity questions, while no clarification was preferred for mental health–related items
A personalized social force-based lane-changing model with a new optimizer
Get PDFUnderstanding and replicating driver lane-changing behavior is essential for developing advanced driver assistance systems that align with driver expectations and for constructing dynamic, realistic traffic flow scenarios in autonomous driving tests. This study proposes a two-dimensional, force-based lane-changing dynamics model that represents vehicle motion as acceleration changes under the influence of (surrounding) social forces. The model captures longitudinal and lateral interactions with neighboring vehicles and incorporates personalized parameters to reflect trajectory-level heterogeneity. A temporal attention mechanism is introduced to model the dynamic shift of driver focus during lane change, ensuring continuity in interaction forces. For parameter calibration, AdaP+ is developed, a gradient-based optimizer that integrates Nesterov momentum, decoupled weight decay, and gradient belief within the Adam framework, and improved with a pruning strategy for better initialization and faster convergence. Experimental findings on the HighD dataset demonstrate that the social force lane change model outperforms baselines in both trajectory fitting and behavioral simulation. Gradient-based optimizers, particularly AdaP+, achieve higher precision than swarm intelligence algorithms. Overall, the proposed model accurately replicates complex lane-change dynamics, while the integration of personalized parameters and attention mechanism effectively captures trajectory-level heterogeneity and interaction continuity, with potential to support naturalistic, personalized lane-change trajectory generation in future connected-vehicle settings
Pathways linking socioeconomic circumstances to childhood dental caries: the mediating role of parenting and oral health behaviours before and after Childsmile implementation
Get PDFObjectives: To determine the extent that parenting styles and oral health behaviours mediate the relationship between socioeconomic circumstances (SEC) and childhood dental caries experience: pre−/post-national roll-out in 2011 of Childsmile, the child oral health improvement programme for Scotland. Methods: A longitudinal design linked 2798 participants from Birth Cohort-1 (following from age 10 months in 2005/06 to age 5 years in 2009/10) and 3015 from Birth Cohort-2 (following from age 10 months in 2011 to age 5 years in 2015) of the Growing Up in Scotland study with caries experience at age five from the National Dental Inspection Programme. Two Structural Equation Models (Birth Cohort-1 and 2) tested an a priori framework to explain the social gradient (SEC: Income Poverty, Area-based Deprivation, Household Education, Household Employment) in caries experience, considering proximal behaviours (toothbrushing, cariogenic diet, regular dental attendance) before introducing validated parenting styles (Parental Responsiveness/Demandingness). Results: Models for both the pre−/post-Childsmile cohorts illustrated similar pathways. Dental attendance and parenting had no direct effect on caries experience. Responsiveness partially mediated the SEC-toothbrushing relationship, while demandingness partially mediated the SEC-diet relationship. Cariogenic diet directly increased caries experience prevalence (β = 0.33/0.24), while increased toothbrushing persistently decreased caries (β = −0.18/−0.13). Total mediated effect of SEC decreased from 58.8% to 39.1%, with the largest relative decrease being directly via toothbrushing (9.5%/4.0%). The effect mediated through parenting pathways remained minimal (4.8%/3.5%). Conclusions: Pathways between SEC and childhood caries were unchanged after Childsmile roll-out, with minimal effects from parenting styles. The diminishing SEC effects via toothbrushing may be positively attributed to Childsmile interventions. The persistent unexplained effect of SEC on caries experience highlights the need for equity-focused structural approaches that address broader socioeconomic inequalities
Proteomic insights into troponin elevation following COVID-19 infection
Get PDFBackground: Raised cardiac troponin-I is a common finding in patients hospitalised with acute viral infections, including but not limited to COVID-19. This often occurs in the absence of overt myocardial injury presenting a challenge for interpretation. The mechanisms underlying troponin elevation are uncertain.
Methods: The CISCO-19 (Cardiovascular Imaging in SARS-CoV-19) study (NCT04403607) is a prospective, multicentre cohort study, in which hospitalised PCR-confirmed COVID-19 participants (N=267) underwent multisystem evaluation at enrolment and at 28–60 days. The study incorporated plasma proteomics (SOMAscan V.4.1), cardiovascular MRI and clinical biomarkers. Of these, 211 had baseline plasma proteomic data and 185 completed follow-up sampling. Matched proteomic and imaging data were available for 155 participants (mean age: 55 years (SD 12); 43% female).
Results: A high likelihood of myocarditis was identified in 13.2% (N=21/159) of participants. High-sensitivity troponin-I was modestly elevated at enrolment (median 3 ng/L; IQR 2–6; n=159). Among males (n=90), 9.3% had a high-sensitivity troponin that exceeded 34 ng/L. Among females (n=69), 4.5% exceeded 16 ng/L. Smooth muscle myosin light chain proteins were downregulated at follow-up (log2 fold change −0.12 to −0.6; all adjusted p<0.02) and positively correlated with high-sensitivity troponin-I, but not N-terminal brain natriuretic peptide or cardiac MRI indices (n=155).
Conclusions: Troponin elevation, exemplified here by COVID-19, could reflect systemic vascular injury. Recognising this mechanism may refine interpretation of cardiac biomarkers in viral illness and supports the investigation of vascular injury in future therapeutic strategies and biomedical studies
Rabies, host population structure, and cross-species transmission to the migratory bat Tadarida brasiliensis in Chile
Get PDFAlthough many bat species migrate, the consequences of migration for bat population structure and rabies virus transmission remain poorly understood. Understanding the spatiotemporal dynamics of bat rabies (Lyssavirus rabies) transmission is important to prevent rabies spillovers to dead-end hosts, including humans. Here, focusing on the long-distance migratory Brazilian free-tailed bat (Tadarida brasiliensis) in South America, we identify the extent of host population and rabies virus structure across Chile. The analysis of 112 cytochrome b sequences from T. brasiliensis individuals and 144 rabies virus sequences submitted to the Chilean national rabies surveillance showed a lack of geographic clustering by municipality or region in Chile. This lack of clustering suggests that the migratory behavior of this species might be homogenizing the population structure of T. brasiliensis and its species-specific rabies virus (TbRV-SA). While most rabies virus sequences of T. brasiliensis (92%) corresponded to the TbRV-SA lineage, we also detected T. brasiliensis individuals infected by rabies viruses that are more strongly associated with other bats, including Lasiurus spp., Histiotus spp., and Myotis spp (8%). In contrast, no other bat species were infected by TbRV-SA, suggesting the potential for a predominant asymmetric cross- species transmission observed in Chile. These results suggest that rabies risk could vary according to migratory bat movement patterns and community composition, especially in areas where cross-species transmission may be facilitated. Our study highlights the need to anticipate the spillover risk to humans and domestic animals associated with the long-distance spread of rabies virus in T. brasiliensis, and calls attention to clarify the role of urban areas as potential hotspots for cross-species transmission
Data sources:
Access Repository Dashboard
Do you manage Open Research Online? Become a CORE Member to access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard! 👇