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This paper concentrates on a simple and robust control method for the discrete time nonlinear systems to fulfill the requirement of predefined accuracy. A sliding mode control method is designed by introducing equivalent dynamic linearization technique according to the input/output (I/O) information merely. A square-root type error transformation method is presented for the tracking error to be restricted within a preassigned zone. The performance of presented control method is demonstrated through experiments on a nonlinear system. Experiment results show that the presented control method has a superior tracking accuracy compared with PID controller and model-free adaptive control (MFAC). • A novel prescribed performance function is proposed to convert the restricted tracking error into an unrestricted one. • A novel sliding mode control framework with a unconstrained variable is investigated to ensure the tracking error in a prescribed region according to I/O data. • This control method is presented for the discrete-time system, which is easily implemented on the hardware system without numerical approximation. • An experiment is conducted on the SMA system to verify a good performance of this control method. [ABSTRACT FROM AUTHOR]

Rural areas' emergency response capacities are generally weaker when compared to tier one cities and this can have an adverse effect on residents' livelihood and health. Evaluation of rural emergency management is of great significance for improving the rural emergency management capacity. This paper innovatively constructs an evaluation system for the emergency management capabilities with the rural public health emergencies, which includes four dimensions: emergency subject, mechanism, resources and concept. A Projection Pursuit model for objectively processing high-dimensional is constructed, and data from 2010 to 2020 in the rural areas of Xiantao City are selected as samples for empirical research. The results show that: (1) Each dimension of emergency management of public health emergencies contributes more than 20% to the ability. Compared with the other three dimensions, contribution of the emergency concept accounted for the lowest proportion, which was 21.69%, and indicates that this dimension is the key factor restricting the improvement of the emergency management capabilities. (2) From 2010 to 2019, the average annual growth rate of comprehensive emergency management capacity in the rural areas of Xiantao City was 14.9%, and by 2020, the rural emergency management capacity, impacted by the COVID-19 epidemic, grew very rapidly with an annual growth rate of 33.8%. (3) The development of an effective rural emergency management capacity system is not sufficient and unbalanced, which leads to the "barrel effect." This study can provide theoretical guidelines for the evaluation of rural emergency management capabilities, and provide methodological support for similar research in other regions. [ABSTRACT FROM AUTHOR]

This work aims to develop a numerical-analytical framework within the kinematic approach of limit analysis to assess the stability of non-circular tunnel faces under seepage conditions with tensile strength cut-off from a discretization-based perspective. Considering the overestimation of the tensile strength of the soil by the Mohr-Coulomb criterion, a modification based on the concept of tensile strength cut-off is recommended to reduce or eliminate the tensile strength. A modified 3D rotational discretization-based failure mechanism incorporating the tension cut-off is generated point-to-point starting from a real non-circular tunnel face to model the face failure, where the failure surface on the top intersects more rapidly due to the increasing rupture angle in the tensile regime. The seepage towards the non-circular tunnel face is numerically simulated, and then the numerical seepage field is extracted into the 3D discretization-based failure mechanism. Within the kinematic approach, the seepage effect is introduced from two aspects: pore pressure and seepage force. A hybrid optimization routine is employed to search for the maximum required face pressure. The developed framework is validated by comparisons with numerical fluid-mechanical simulations and previous studies. Afterward, parametric analyses are carried out on different seepage conditions, different face pressure distributions, different soil strengths, and different tension cut-off conditions. The developed framework can give insight into the combined effect of the tension cut-off and seepage on the stability of non-circular tunnel faces under various conditions. [ABSTRACT FROM AUTHOR]