101 research outputs found
PMCV hypersurfaces in non-flat pseudo-Riemannian space forms
In this paper, we prove that PMCV (i.e. \Delta\vec{H} is proportional to
\vec{H}) hypersurface M^n_r of a non-flat pseudo-Riemannian space form
N^{n+1}_s(c) with at most two distinct principal curvatures is minimal or
locally isoparametric, and compute the mean curvature for the isoparametric
ones. As an application, we give full classification results of such
non-minimal Lorentzian hypersurfaces of non-flat Lorentz space forms
LSSANet: A Long Short Slice-Aware Network for Pulmonary Nodule Detection
Convolutional neural networks (CNNs) have been demonstrated to be highly
effective in the field of pulmonary nodule detection. However, existing CNN
based pulmonary nodule detection methods lack the ability to capture long-range
dependencies, which is vital for global information extraction. In computer
vision tasks, non-local operations have been widely utilized, but the
computational cost could be very high for 3D computed tomography (CT) images.
To address this issue, we propose a long short slice-aware network (LSSANet)
for the detection of pulmonary nodules. In particular, we develop a new
non-local mechanism termed long short slice grouping (LSSG), which splits the
compact non-local embeddings into a short-distance slice grouped one and a
long-distance slice grouped counterpart. This not only reduces the
computational burden, but also keeps long-range dependencies among any elements
across slices and in the whole feature map. The proposed LSSG is easy-to-use
and can be plugged into many pulmonary nodule detection networks. To verify the
performance of LSSANet, we compare with several recently proposed and
competitive detection approaches based on 2D/3D CNN. Promising evaluation
results on the large-scale PN9 dataset demonstrate the effectiveness of our
method. Code is at https://github.com/Ruixxxx/LSSANet.Comment: MICCAI 202
Scale-aware Test-time Click Adaptation for Pulmonary Nodule and Mass Segmentation
Pulmonary nodules and masses are crucial imaging features in lung cancer
screening that require careful management in clinical diagnosis. Despite the
success of deep learning-based medical image segmentation, the robust
performance on various sizes of lesions of nodule and mass is still
challenging. In this paper, we propose a multi-scale neural network with
scale-aware test-time adaptation to address this challenge. Specifically, we
introduce an adaptive Scale-aware Test-time Click Adaptation method based on
effortlessly obtainable lesion clicks as test-time cues to enhance segmentation
performance, particularly for large lesions. The proposed method can be
seamlessly integrated into existing networks. Extensive experiments on both
open-source and in-house datasets consistently demonstrate the effectiveness of
the proposed method over some CNN and Transformer-based segmentation methods.
Our code is available at https://github.com/SplinterLi/SaTTCAComment: 11 pages, 3 figures, MICCAI 202
Order matters: How altering the sequence of performance events shapes perceived quality formation
Reputation research often employs rankings which combine both the prominence and perceived quality dimensions of reputation. Though this approach has merit, it neglects nuances in the formation of perceived firm quality – i.e., how stakeholders perceive a firm’s capabilities. Since perceptions are influenced by how information is presented, we posit that the patterns of a firm’s performances – their order and interval – explain variance in perceived quality beyond valence (absolute performance level), alone. We employ two experiments and an archival study to manipulate product ratings and collect perceived quality scores (experimentally), and use trajectory of performance outcomes to predict market valuation as a perceived quality proxy (archivally). Results suggest that while valence matters most for a firm’s perceived quality, presenting identical performance events with distinct orders and intervals changes perceived quality impressions, at least until new information is presented. We enumerate our findings and outline areas for future research on stakeholder perceptions
Inter-Calibration of Satellite Passive Microwave Land Observations from AMSR-E and AMSR2 Using Overlapping FY3B-MWRI Sensor Measurements
The development and continuity of consistent long-term data records from similar overlapping satellite observations is critical for global monitoring and environmental change assessments. We developed an empirical approach for inter-calibration of satellite microwave brightness temperature (Tb) records over land from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) and Microwave Scanning Radiometer 2 (AMSR2) using overlapping Tb observations from the Microwave Radiation Imager (MWRI). Double Differencing (DD) calculations revealed significant AMSR2 and MWRI biases relative to AMSR-E. Pixel-wise linear relationships were established from overlapping Tb records and used for calibrating MWRI and AMSR2 records to the AMSR-E baseline. The integrated multi-sensor Tb record was largely consistent over the major global vegetation and climate zones; sensor biases were generally well calibrated, though residual Tb differences inherent to different sensor configurations were still present. Daily surface air temperature estimates from the calibrated AMSR2 Tb inputs also showed favorable accuracy against independent measurements from 142 global weather stations (R2 ≥ 0.75, RMSE ≤ 3.64 °C), but with slightly lower accuracy than the AMSR-E baseline (R2 ≥ 0.78, RMSE ≤ 3.46 °C). The proposed method is promising for generating consistent, uninterrupted global land parameter records spanning the AMSR-E and continuing AMSR2 missions
Development of finite element models for thermal multiphase flow in deformable porous media with anisotropic full permeability tensor
Bibliography: p. 297-31
An Improved Endmember Selection Method Based on Vector Length for MODIS Reflectance Channels
Endmember selection is the basis for sub-pixel land cover classifications using multiple endmember spectral mixture analysis (MESMA) that adopts variant endmember matrices for each pixel to mitigate errors caused by endmember variability in SMA. A spectral library covering a large number of endmembers can account for endmember variability, but it also lowers the computational efficiency. Therefore, an efficient endmember selection scheme to optimize the library is crucial to implement MESMA. In this study, we present an endmember selection method based on vector length. The spectra of a land cover class were divided into subsets using vector length intervals of the spectra, and the representative endmembers were derived from these subsets. Compared with the available endmember average RMSE (EAR) method, our approach improved the computational efficiency in endmember selection. The method accuracy was further evaluated using spectral libraries derived from the ground reference polygon and Moderate Resolution Imaging Spectroradiometer (MODIS) imagery respectively. Results using the different spectral libraries indicated that MESMA combined with the new approach performed slightly better than EAR method, with Kappa coefficient improved from 0.75 to 0.78. A MODIS image was used to test the mapping fraction, and the representative spectra based on vector length successfully modeled more than 90% spectra of the MODIS pixels by 2-endmember models
A GEO satellite mobile telecommunications system architecture design based on UMTS/S-UMTS
China has begun to consider the plan of establishing its public satellite mobile network (PSMN) due to the national demands. As the result of one earlier research sponsored by the Ministry of Science and Technology of China, a network architecture of the satellite mobile service system, which is compatible to 3GPP/UMTS R4 and bases on appropriate GEO satellite on-board processor modeling, is proposed in this paper, with several new defined functional entities, interfaces, and protocols. The proposed network architecture could act as a basis of further design of the China's PSMN system.Computer Science, Hardware & ArchitectureEngineering, Electrical & ElectronicTelecommunicationsEICPCI-S(ISTP)
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