105 research outputs found
Protocol selection for second-order consensus against disturbance
Noticing that both the absolute and relative velocity protocols can solve the
second-order consensus of multi-agent systems, this paper aims to investigate
which of the above two protocols has better anti-disturbance capability, in
which the anti-disturbance capability is measured by the L2 gain from the
disturbance to the consensus error. More specifically, by the orthogonal
transformation technique, the analytic expression of the L2 gain of the
second-order multi-agent system with absolute velocity protocol is firstly
derived, followed by the counterpart with relative velocity protocol. It is
shown that both the L2 gains for absolute and relative velocity protocols are
determined only by the minimum non-zero eigenvalue of Laplacian matrix and the
tunable gains of the state and velocity. Then, we establish the graph
conditions to tell which protocol has better anti-disturbance capability.
Moreover, we propose a two-step scheme to improve the anti-disturbance
capability of second-order multi-agent systems. Finally, simulations are given
to illustrate the effectiveness of our findings
Media impact research: a discrete SIR epidemic model with threshold switching and nonlinear infection forces
The media's coverage has the potential to impact human behavior and aid in the control of emergent infectious diseases. We aim to quantify and evaluate the extent to which media coverage can influence infectious disease control through a mathematical model, thus proposing a switching epidemic model that considers the effect of media coverage. The threshold strategy incorporates media influence only when the number of infected cases surpasses a specific threshold; otherwise, it is disregarded. When conducting qualitative analysis of two subsystems, focusing on the existence and stability of equilibria. Using numerical methods, the codimension-2 bifurcation analysis is adopted here to investigate the various types of equilibria within the switching system that play a vital role in pest control. On the other hand, codimension-1 bifurcation analysis reveals the existence of periodic, chaotic solutions, period-doubling bifurcations, multiple attractors and other complexities within the proposed model, which could pose challenges in disease control. Additionally, the impact of key parameters on epidemic outbreaks is analyzed, such as the initial values of susceptible and infective individuals, and discuss the potential benefits of mass media coverage in preventing emerging infectious diseases. The modeling and analytical techniques developed for threshold control strategies can be applied to other disease control efforts
OnUVS: Online Feature Decoupling Framework for High-Fidelity Ultrasound Video Synthesis
Ultrasound (US) imaging is indispensable in clinical practice. To diagnose
certain diseases, sonographers must observe corresponding dynamic anatomic
structures to gather comprehensive information. However, the limited
availability of specific US video cases causes teaching difficulties in
identifying corresponding diseases, which potentially impacts the detection
rate of such cases. The synthesis of US videos may represent a promising
solution to this issue. Nevertheless, it is challenging to accurately animate
the intricate motion of dynamic anatomic structures while preserving image
fidelity. To address this, we present a novel online feature-decoupling
framework called OnUVS for high-fidelity US video synthesis. Our highlights can
be summarized by four aspects. First, we introduced anatomic information into
keypoint learning through a weakly-supervised training strategy, resulting in
improved preservation of anatomical integrity and motion while minimizing the
labeling burden. Second, to better preserve the integrity and textural
information of US images, we implemented a dual-decoder that decouples the
content and textural features in the generator. Third, we adopted a
multiple-feature discriminator to extract a comprehensive range of visual cues,
thereby enhancing the sharpness and fine details of the generated videos.
Fourth, we constrained the motion trajectories of keypoints during online
learning to enhance the fluidity of generated videos. Our validation and user
studies on in-house echocardiographic and pelvic floor US videos showed that
OnUVS synthesizes US videos with high fidelity.Comment: 14 pages, 13 figures and 6 table
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