50 research outputs found
Complex-Sigmoid Function for Complex-Valued Neural Networks (Dynamical Systems : Theories to Applications and Applications to Theories)
Backbone-based Dynamic Graph Spatio-Temporal Network for Epidemic Forecasting
Accurate epidemic forecasting is a critical task in controlling disease
transmission. Many deep learning-based models focus only on static or dynamic
graphs when constructing spatial information, ignoring their relationship.
Additionally, these models often rely on recurrent structures, which can lead
to error accumulation and computational time consumption. To address the
aforementioned problems, we propose a novel model called Backbone-based Dynamic
Graph Spatio-Temporal Network (BDGSTN). Intuitively, the continuous and smooth
changes in graph structure, make adjacent graph structures share a basic
pattern. To capture this property, we use adaptive methods to generate static
backbone graphs containing the primary information and temporal models to
generate dynamic temporal graphs of epidemic data, fusing them to generate a
backbone-based dynamic graph. To overcome potential limitations associated with
recurrent structures, we introduce a linear model DLinear to handle temporal
dependencies and combine it with dynamic graph convolution for epidemic
forecasting. Extensive experiments on two datasets demonstrate that BDGSTN
outperforms baseline models and ablation comparison further verifies the
effectiveness of model components. Furthermore, we analyze and measure the
significance of backbone and temporal graphs by using information metrics from
different aspects. Finally, we compare model parameter volume and training time
to confirm the superior complexity and efficiency of BDGSTN
Oscillation dynamics underlie functional switching of NF-κB for B-cell activation.
Transcription factor nuclear factor kappa B (NF-κB) shows cooperative switch-like activation followed by prolonged oscillatory nuclear translocation in response to extracellular stimuli. These dynamics are important for activation of the NF-κB transcriptional machinery, however, NF-κB activity regulated by coordinated actions of these dynamics has not been elucidated at the system level. Using a variety of B cells with artificially rewired NF-κB signaling networks, we show that oscillations and switch-like activation of NF-κB can be dissected and that, under some conditions, these two behaviors are separated upon antigen receptor activation. Comprehensive quantitative experiments and mathematical analysis showed that the functional role of switch activation in the NF-κB system is to overcome transient IKK (IκB kinase) activity to amplify nuclear translocation of NF-κB, thereby inducing the prolonged NF-κB oscillatory behavior necessary for target gene expression and B-cell activation
Robustness of oscillatory behavior in correlated networks
Understanding network robustness against failures of network units is useful for preventing large-scale breakdowns and damages in real-world networked systems. The tolerance of networked systems whose functions are maintained by collective dynamical behavior of the network units has recently been analyzed in the framework called dynamical robustness of complex networks. The effect of network structure on the dynamical robustness has been examined with various types of network topology, but the role of network assortativity, or degree–degree correlations, is still unclear. Here we study the dynamical robustness of correlated (assortative and disassortative) networks consisting of diffusively coupled oscillators. Numerical analyses for the correlated networks with Poisson and power-law degree distributions show that network assortativity enhances the dynamical robustness of the oscillator networks but the impact of network disassortativity depends on the detailed network connectivity. Furthermore, we theoretically analyze the dynamical robustness of correlated bimodal networks with two-peak degree distributions and show the positive impact of the network assortativity