231 research outputs found

    Precise Large Deviations For The Total Population Of Heavy-Tailed Subcritical Branching Process With Immigration

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    In this article we focus on the partial sum Sn=X1+⋯+XnS_{n}=X_{1}+\cdots+X_{n} of the subcritical branching process with immigration {Xn}n∈N+\{X_{n}\}_{n\in\mathbb{N_{+}}}, under the condition that one of the offspring ξ\xi or immigration η\eta is regularly varying. The tail distribution of SnS_n is heavily dependent on that of ξ\xi and η\eta, and a precise large deviation probability for SnS_{n} is specified. (i)When the tail of offspring ξ\xi is lighter than immigration η\eta, uniformly for x≥xnx\geq x_{n}, P(Sn−ESn>x)∼c1nP(η>x)P(S_{n}-ES_{n}>x)\sim c_{1}nP(\eta>x) with some constant c1c_{1} and sequence {xn}\{x_{n}\}, where c1c_{1} is only related to the mean of offspring; (ii) When the tail of immigration η\eta is not heavier than offspring ξ\xi, uniformly for x≥xnx\geq x_{n},P(SnESn>x)∼c2nP(ξ>x)P(S_{n} ES_{n}>x)\sim c_{2}nP(\xi>x) with some constant c2c_{2} and sequence {xn}\{x_{n}\}, where c2c_{2} is related to both the mean of offspring and the mean of immigration

    Precise large deviation for stationary sequence of branching process with immigration

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    It is known that there exists the stationary sequence of branching process with immigration {Xn}n∈Z\{X_{n}\}_{n\in\mathbb{Z}} under some conditions (Foster and Williamson (1971)), when the offspring is critical or subcritical. A precise large deviation probability for the partial sum Sn=X1+⋯+XnS_{n}=X_{1}+\cdots+X_{n} is specified, the significant difference is revealed for the critical and subcritical cases.Comment: arXiv admin note: substantial text overlap with arXiv:2405.0407

    Characteristics Analysis of Non-linear Torsional Vibration in Engine and Generator Shafting system

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    To solve the non-linear torsional vibration problem of engine and generator shafting causing body structural vibration and noise in motorized wheel vehicle, where the engine and the generator connected directly. First of all, analysis the characteristics of the shafting system, besides the external shock excitation of engine and generator. Then, through lumped parameter model method, mathematical model of the non-linear torsional vibration was established, which could reflect the dynamic characteristics of the system. Analysis the effect of mechanical parameters and electromagnetic parameters on the shafting. And get the non-linear differential equations of the system torsional vibration, which expresses the relation between structural parameters, electromagnetic parameters and the system dynamic characteristics. And multiple scales method was used to solve the equations. Non-contact measurement method was used in the torsional vibration test. Finally, consistency of the results, indicate that the research method used is reliability and accuracy, and get the critical speed of the shafting torsional vibration
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