76 research outputs found
EdgeCalib: Multi-Frame Weighted Edge Features for Automatic Targetless LiDAR-Camera Calibration
In multimodal perception systems, achieving precise extrinsic calibration
between LiDAR and camera is of critical importance. Previous calibration
methods often required specific targets or manual adjustments, making them both
labor-intensive and costly. Online calibration methods based on features have
been proposed, but these methods encounter challenges such as imprecise feature
extraction, unreliable cross-modality associations, and high scene-specific
requirements. To address this, we introduce an edge-based approach for
automatic online calibration of LiDAR and cameras in real-world scenarios. The
edge features, which are prevalent in various environments, are aligned in both
images and point clouds to determine the extrinsic parameters. Specifically,
stable and robust image edge features are extracted using a SAM-based method
and the edge features extracted from the point cloud are weighted through a
multi-frame weighting strategy for feature filtering. Finally, accurate
extrinsic parameters are optimized based on edge correspondence constraints. We
conducted evaluations on both the KITTI dataset and our dataset. The results
show a state-of-the-art rotation accuracy of 0.086{\deg} and a translation
accuracy of 0.977 cm, outperforming existing edge-based calibration methods in
both precision and robustness
Broad and strong memory CD4(+)and CD8(+)T cells induced by SARS-CoV-2 in UK convalescent individuals following COVID-19
The development of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines and therapeutics will depend on understanding viral immunity. We studied T cell memory in 42 patients following recovery from COVID-19 (28 with mild disease and 14 with severe disease) and 16 unexposed donors, using interferon-Îł-based assays with peptides spanning SARS-CoV-2 except ORF1. The breadth and magnitude of T cell responses were significantly higher in severe as compared with mild cases. Total and spike-specific T cell responses correlated with spike-specific antibody responses. We identified 41 peptides containing CD4+ and/or CD8+ epitopes, including six immunodominant regions. Six optimized CD8+ epitopes were defined, with peptideâMHC pentamer-positive cells displaying the central and effector memory phenotype. In mild cases, higher proportions of SARS-CoV-2-specific CD8+ T cells were observed. The identification of T cell responses associated with milder disease will support an understanding of protective immunity and highlights the potential of including non-spike proteins within future COVID-19 vaccine design
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Doctoral thesis recital (violin)
Piano trio no.1 in D minor, op.49 / Felix Mendelssohn -- Piano trio no.1 in D minor, op.32 / Anton Arensky.Musi
Recommended from our members
Doctoral thesis recital (violin)
Scherzo-Sonatensatz from F.A.E. Sonata / Johannes Brahms -- Sonata no.6 for solo violin / Eugene Ysaye -- Sonata for violin and piano, op.80 / Sergei Prokofiev.Musi
Recommended from our members
Doctoral thesis recital (violin)
Violin sonata no. 8 in G major, op. 30 no. 3 / Ludwig van Beethoven -- Harvest fishermen's song / Zili Li -- Sonata in A major for violin and piano / CeÌsar Franck.Musi
Temporal Response of Mesocarnivores to Human Activity and Infrastructure in Taihang Mountains, Central North China: Shifts in Activity Patterns and Their Overlap
Mesocarnivores play essential roles in terrestrial ecosystems, but anthropocentric disturbances have profoundly transformed their intraguild interactions worldwide. In this study, we explored how a guild of four mesocarnivores (red fox Vulpes vulpes, leopard cat Prionailurus bengalensis, Asian badger Meles leucurus, and hog badger Arctonyx collaris) partition their temporal niche in the temperate montane forests in North China under different human influences. We conducted a systemic camera-trapping survey on the study species in the central Taihang Mountains from 2016 to 2020. With an extensive survey effort of 111,063 camera-days from 187 camera stations, we obtained 10,035 independent detections of the four mesocarnivores and examined the activity patterns of each species under different levels of human disturbance and their overlaps. The results showed that, while the leopard cat and the badgers shifted their activity towards nocturnality, the red fox showed no significant change. The leopard catâs degree of nocturnality varied between growing and non-growing seasons, likely a response to avoid humans and other competitors. However, the activity overlaps between species pairs demonstrated no statistically significant difference, indicating a long-developed coexistence mechanism that is homogenous across the landscape. Demonstrating how mesocarnivores shift activity patterns in response to human risks while partitioning resources, this study enhances our understanding of mesocarnivore behavioral changes and interspecific interactions at humanânature interfaces
A Discontinuous Galerkin Surface Integral Solution for Scattering from Homogeneous Objects with High Dielectric Constant
The discontinuous Galerkin (DG) method for homogeneous bodies has been studied and shown to be an efficient tool for multiscale homogeneous bodies. However, the slow convergence of DG with the block diagonal preconditioner (BDP) is still observed in solving high contrast homogeneous bodies. An efficient preconditioning approach is designed for the DG method in this communication by using the sparsing approach on the near-field matrix of the whole region. The iteration convergence speed of the DG method is improved while the computing resources for constructing the preconditioner are effectively reduced. Numerical experiments demonstrate the capability of the presented DG method for multiscale homogeneous bodies, especially for those with a high dielectric constant.Peer reviewe
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