400 research outputs found
Controllability and Observability of Fractional Linear Systems with Two Different Orders
This paper is concerned with the controllability and observability for a class of fractional linear systems with two different orders. The sufficient and necessary conditions for state controllability and state observability of such systems are established. The results obtained extend some existing results of controllability and observability for fractional dynamical systems
Leveraging BEV Representation for 360-degree Visual Place Recognition
This paper investigates the advantages of using Bird's Eye View (BEV)
representation in 360-degree visual place recognition (VPR). We propose a novel
network architecture that utilizes the BEV representation in feature
extraction, feature aggregation, and vision-LiDAR fusion, which bridges visual
cues and spatial awareness. Our method extracts image features using standard
convolutional networks and combines the features according to pre-defined 3D
grid spatial points. To alleviate the mechanical and time misalignments between
cameras, we further introduce deformable attention to learn the compensation.
Upon the BEV feature representation, we then employ the polar transform and the
Discrete Fourier transform for aggregation, which is shown to be
rotation-invariant. In addition, the image and point cloud cues can be easily
stated in the same coordinates, which benefits sensor fusion for place
recognition. The proposed BEV-based method is evaluated in ablation and
comparative studies on two datasets, including on-the-road and off-the-road
scenarios. The experimental results verify the hypothesis that BEV can benefit
VPR by its superior performance compared to baseline methods. To the best of
our knowledge, this is the first trial of employing BEV representation in this
task
Diosgenin inhibits cell proliferation of primary human thyrocytes via downregulation of PI3K/Akt signaling pathway
Purpose: To determine the potential influence of diosgenin on proliferation of human thyrocytes and its possible mechanism.Methods: Primary human thyrocytes were cultured and treated with diosgenin at various time intervals. Anti-proliferative activity was determined by MTT assay. Cell proliferation was evaluated by EdU assay while cell cycle was analyzed using fluorescence-activated cell sorting (FACS) method. Protein expression of p21 (CIP1), p27 (KIP1), cyclins, protein kinase B (Akt), phosphatidylinositol 3 kinase (PI3K) and p-Akt was determined by the western blot.Results: Diosgenin inhibited proliferation of primary human thyrocytes and caused G0/G1 arrest in a concentration-dependent manner. It also downregulated cyclin D1 and phosphorylation of PI3K and Akt, but upregulated p21 and p27.Conclusion: Inhibition of proliferation of primary human thyrocytes by diosgenin occurs viadownregulation of PI3K/Akt signaling pathway. Therefore, diosgenin can be developed as a potential drug for the treatment of thyroid disease.Keywords: Diosgenin, Proliferation, Primary human thyrocytes, PI3K/Akt signaling pathwa
Mutual information measure of visual perception based on noisy spiking neural networks
Note that images of low-illumination are weak aperiodic signals, while mutual information can be used as an effective measure for the shared information between the input stimulus and the output response of nonlinear systems, thus it is possible to develop novel visual perception algorithm based on the principle of aperiodic stochastic resonance within the frame of information theory. To confirm this, we reveal this phenomenon using the integrate-and-fire neural networks of neurons with noisy binary random signal as input first. And then, we propose an improved visual perception algorithm with the image mutual information as assessment index. The numerical experiences show that the target image can be picked up with more easiness by the maximal mutual information than by the minimum of natural image quality evaluation (NIQE), which is one of the most frequently used indexes. Moreover, the advantage of choosing quantile as spike threshold has also been confirmed. The improvement of this research should provide large convenience for potential applications including video tracking in environments of low illumination
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