360 research outputs found
Robustness on distributed coupling networks with multiple dependent links from finite functional components
The rapid advancement of technology underscores the critical importance of
robustness in complex network systems. This paper presents a framework for
investigating the structural robustness of interconnected network models. This
paper presents a framework for investigating the structural robustness of
interconnected network models. In this context, we define functional nodes
within interconnected networks as those belonging to clusters of size greater
than or equal to in the local network, while maintaining at least
significant dependency links. This model presents precise analytical
expressions for the cascading failure process, the proportion of functional
nodes in the stable state, and a methodology for calculating the critical
threshold. The findings reveal an abrupt phase transition behavior in the
system following the initial failure. Additionally, we observe that the system
necessitates higher internal connection densities to avert collapse, especially
when more effective support links are required. These results are validated
through simulations using both Poisson and power-law network models, which
align closely with the theoretical outcomes. The method proposed in this study
can assist decision-makers in designing more resilient reality-dependent
systems and formulating optimal protection strategies
FedA3I: Annotation Quality-Aware Aggregation for Federated Medical Image Segmentation against Heterogeneous Annotation Noise
Federated learning (FL) has emerged as a promising paradigm for training
segmentation models on decentralized medical data, owing to its
privacy-preserving property. However, existing research overlooks the prevalent
annotation noise encountered in real-world medical datasets, which limits the
performance ceilings of FL. In this paper, we, for the first time, identify and
tackle this problem. For problem formulation, we propose a contour evolution
for modeling non-independent and identically distributed (Non-IID) noise across
pixels within each client and then extend it to the case of multi-source data
to form a heterogeneous noise model (i.e., Non-IID annotation noise across
clients). For robust learning from annotations with such two-level Non-IID
noise, we emphasize the importance of data quality in model aggregation,
allowing high-quality clients to have a greater impact on FL. To achieve this,
we propose Federated learning with Annotation quAlity-aware AggregatIon, named
FedA3I, by introducing a quality factor based on client-wise noise estimation.
Specifically, noise estimation at each client is accomplished through the
Gaussian mixture model and then incorporated into model aggregation in a
layer-wise manner to up-weight high-quality clients. Extensive experiments on
two real-world medical image segmentation datasets demonstrate the superior
performance of FedAI against the state-of-the-art approaches in dealing
with cross-client annotation noise. The code is available at
https://github.com/wnn2000/FedAAAI.Comment: Accepted at AAAI'2
Robustness of coupled networks with multiple support from functional components at different scales
Robustness is an essential component of modern network science. Here, we investigate the robustness of coupled networks where the functionality of a node depends not only on its connectivity, here measured by the size of its connected component in its own network, but also the support provided by at least M links from another network. We here develop a theoretical framework and investigate analytically and numerically the cascading failure process when the system is under attack, deriving expressions for the proportion of functional nodes in the stable state, and the critical threshold when the system collapses. Significantly, our results show an abrupt phase transition and we derive the minimum inner and inter-connectivity density necessary for the system to remain active. We also observe that the system necessitates an increased density of links inside and across networks to prevent collapse, especially when conditions on the coupling between the networks are more stringent. Finally, we discuss the importance of our results in real-world settings and their potential use to aid decision-makers design more resilient infrastructure systems
The OX40/OX40L Axis Regulates T Follicular Helper Cell Differentiation: Implications for Autoimmune Diseases
T Follicular helper (Tfh) cells, a unique subset of CD4+ T cells, play an essential role in B cell development and the formation of germinal centers (GCs). Tfh differentiation depends on various factors including cytokines, transcription factors and multiple costimulatory molecules. Given that OX40 signaling is critical for costimulating T cell activation and function, its roles in regulating Tfh cells have attracted widespread attention. Recent data have shown that OX40/OX40L signaling can not only promote Tfh cell differentiation and maintain cell survival, but also enhance the helper function of Tfh for B cells. Moreover, upregulated OX40 signaling is related to abnormal Tfh activity that causes autoimmune diseases. This review describes the roles of OX40/OX40L in Tfh biology, including the mechanisms by which OX40 signaling regulates Tfh cell differentiation and functions, and their close relationship with autoimmune diseases
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