99 research outputs found

    Existence of solutions of a second-order impulsive differential equation

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    Dynamics of an SEIR model with media coverage mediated nonlinear infectious force

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    Media coverage can greatly impact the spread of infectious diseases. Taking into consideration the impacts of media coverage, we propose an SEIR model with a media coverage mediated nonlinear infection force. For this novel disease model, we identify the basic reproduction number using the next generation matrix method and establish the global threshold results: If the basic reproduction number \mathcal{R}_{0} < 1 , then the disease-free equilibrium P0 P_{0} is stable, and the disease dies out. If \mathcal{R}_{0} > 1 , then the endemic equilibrium P P^{*} is stable, and the disease persists. Sensitivity analysis indicates that the basic reproduction number R0 \mathcal{R}_{0} is most sensitive to the population recruitment rate Λ \Lambda and the disease transmission rate β1 \beta _{1}

    Self-Similar Random Process and Chaotic Behavior In Serrated Flow of High Entropy Alloys

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    The statistical and dynamic analyses of the serrated-flow behavior in the nanoindentation of a high-entropy alloy, Al0.5CoCrCuFeNi, at various holding times and temperatures, are performed to reveal the hidden order associated with the seemingly-irregular intermittent flow. Two distinct types of dynamics are identified in the high-entropy alloy, which are based on the chaotic time-series, approximate entropy, fractal dimension, and Hurst exponent. The dynamic plastic behavior at both room temperature and 200 °C exhibits a positive Lyapunov exponent, suggesting that the underlying dynamics is chaotic. The fractal dimension of the indentation depth increases with the increase of temperature, and there is an inflection at the holding time of 10 s at the same temperature. A large fractal dimension suggests the concurrent nucleation of a large number of slip bands. In particular, for the indentation with the holding time of 10 s at room temperature, the slip process evolves as a self-similar random process with a weak negative correlation similar to a random walk

    SurrealDriver: Designing Generative Driver Agent Simulation Framework in Urban Contexts based on Large Language Model

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    Simulation plays a critical role in the research and development of autonomous driving and intelligent transportation systems. However, the current simulation platforms exhibit limitations in the realism and diversity of agent behaviors, which impede the transfer of simulation outcomes to the real world. In this paper, we propose a generative driver agent simulation framework based on large language models (LLMs), capable of perceiving complex traffic scenarios and providing realistic driving maneuvers. Notably, we conducted interviews with 24 drivers and used their detailed descriptions of driving behavior as chain-of-thought prompts to develop a `coach agent' module, which can evaluate and assist driver agents in accumulating driving experience and developing human-like driving styles. Through practical simulation experiments and user experiments, we validate the feasibility of this framework in generating reliable driver agents and analyze the roles of each module. The results show that the framework with full architect decreased the collision rate by 81.04% and increased the human-likeness by 50%. Our research proposes the first urban context driver agent simulation framework based on LLMs and provides valuable insights into the future of agent simulation for complex tasks.Comment: 12 pages, 8 figure

    One-dimensional coordination polymers containing penta-supertetrahedral sulfide clusters linked by dipyridyl ligands

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    通讯作者地址: Feng, PY (通讯作者), Univ Calif Riverside, Dept Chem, Riverside, CA 92521 USA 地址: 1. Univ Calif Riverside, Dept Chem, Riverside, CA 92521 USA 2. Calif State Univ Long Beach, Dept Chem & Biochem, Long Beach, CA 90840 USA 电子邮件地址: [email protected] new one-dimensional coordination polymers [Zn8S(SC6H5)(14).C12H10N2](1), [Zn7CoS(SC6H5)14(.)C(13)H(14)N(2)](2) and [Zn8S(SC6H5)14(.)C(13)H(14)N(2)](3) have been prepared containing penta-supertetrahedral clusters and linear crosslinking dipyridyl ligands; the two complexes show optical transitions with band gaps of similar to 3.44 eV (1) and similar to 3.54 eV (2)
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