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A new procedure for determining the asymptotic stability with probability one of randomtime- delay-controlled quasi-integrable Hamiltonian systems is proposed. Such a system is formulated as continuous-discrete hybrid system and the random time delay is modeled as a Markov jump process. A three-step approximation is taken to simplify such hybrid system: (i) the randomly periodic approximate solution property of the system is used to convert the random time delay control into the control without time delay but with delay time as parameter: (ii) a limit theorem is used to transform the hybrid system with Markov jump parameter into one without jump parameter; and (iii) the stochastic averaging method for quasi-integrable Hamiltonian systems is applied to reduce the system into a set of averaged ltd stochastic differential equations. An approximate expression for the largest Lyapunov exponent of the system is derived from the linearized averaged ltd equations and the necessary and sufficient condition for the asymptotic stability with probability one of the system is obtained. The application and effectiveness of the proposed procedure are demonstrated by using an example of stochastically driven twodegrees- of-freedom networked control system (NCS) with random time delay. [ABSTRACT FROM AUTHOR]

The semi-infinite time optimal control for a class of stochastically excited Markovian jump nonlinear system is investigated. Using stochastic averaging, each form of the system is reduced to a one-dimensional partially averaged Itô equation of total energy. A finite set of coupled dynamical programming equations is then set up based on the stochastic dynamical programming principle and Markovian jump rules, from which the optimal control force is obtained. The stationary response of the optimally controlled system is predicted by solving the Fokker-Planck-Kolmogorov (FPK) equation associated with the fully averaged Itô equation. Two examples are worked out in detail to illustrate the application and effectiveness of the proposed control strategy. [ABSTRACT FROM AUTHOR]

A bounded stochastic optimal semi-active control strategy for random excited hysteretic systems by using MR damper is proposed and illustrated by an example of a single degree-of-freedom hysteretic system. First, the dynamics of MR damper and the hysteretic force are expressed by using the Bouc-Wen model. Then, the system is converted into an equivalent nonlinear non-hysteretic stochastic system, from which the optimal bounded semi-active control law consisting of optimal unbounded control and bang-bang control is derived by using stochastic averaging method and stochastic dynamical programming principle. Finally, the response of optimally controlled system is predicted from solving the Fokker-Planck-Kolmogorov (FPK) equation associated with the fully averaged Itô equation. Numerical results show that the proposed control strategy has high control effectiveness and efficiency. [ABSTRACT FROM AUTHOR]

A modified bounded optimal control strategy for quasi integrable Hamiltonian systems subject to actuator saturation is proposed. First, an n degree-of-freedom (DOF) weakly controlled quasi Hamiltonian system subject to Gaussian white noise excitation is formulated and converted into Itô equations by adding Wong-Zakai correction terms. Then, the averaged Itô stochastic differential equations and dynamical programming equation are derived by using stochastic averaging method and the stochastic dynamical programming principle, respectively. The optimal control law consisting of unbounded optimal control and bounded bang-bang control is obtained from solving the dynamical programming equation. Finally, an example of a two DOF controlled quasi integrable Hamiltonian system is worked out in detail. Numerical results show that the proposed control strategy has high control effectiveness and efficiency and the chattering is reduced significantly comparing with bang-bang control strategy. [ABSTRACT FROM AUTHOR]

Objective: To investigate the association between cytokines and ocular chronic graft-versus-host disease (cGVHD) and identify specific biomarkers for ocular cGVHD to enhance clinical diagnosis, treatment, and evaluation. Methods: A mouse model of cGVHD was established to explore the correlation between cGVHD and serum cytokines. Based on the findings from the animal experiments and literature review, a panel of 16 cytokine combinations was identified. Enzyme-linked immunosorbent assay (ELISA) was used to compare the cytokine concentrations in the serum and tear samples from patients who underwent allogeneic hematopoietic stem cell transplantation from June 2017 to March 2022 at the Medical Center of Hematology, Xinqiao Hospital, Army Medical University. Results: ① Compared with the control group, mice with cGVHD exhibited elevated serum IL-1β, IL-6, IL-8, IL-17, IFN-γ, CX3CL1, CXCL11, CXCL13, CCL11, and CCL19 concentrations (all P <0.05). ② Analysis of the cytokine profiles of the serum and tear samples revealed that compared with patients without ocular cGVHD, those with ocular cGVHD exhibited increased serum IL-8 [ P =0.032, area under the curve (AUC) =0.678]; decreased serum IL-10 ( P =0.030, AUC=0.701) ; elevated IL-8, IFN-γ, CXCL9, and CCL17 in tear samples; and lower IL-10 and CCL19 in tear samples (all P <0.05, all AUC>0.7). Moreover, cytokines in tear samples showed correlations with ocular surface parameters related to ocular cGVHD. Conclusions: Tear fluid demonstrates greater specificity and sensitivity as a biomarker for diagnosing ocular cGVHD than serum biomarkers. Among the identified cytokines in tear samples, IL-8, IL-10, IFN-γ, CXCL9, CCL17, and CCL19 serve as diagnostic biomarkers for ocular cGVHD post-transplantation, offering practical reference value for diagnosis.