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Predefined-Time Sliding Mode Control with Prescribed Convergent Region

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IEEE/CAA Journal of Automatica Sinica 2022年第5期9卷 934-936页

作者： Ke shao Jinchuan Zheng Tsinghua Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055China School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyHawthornVIC 3122Australia IEEE

Dear editor,K1 In recent years,the finite-time and fixed-time control techniques have drawn much *** letter will present a new method for designing a predefined-time adaptive sliding mode controller with prescribed convergent *** specifically,class function is used to construct the sliding function,and to achieve a real sliding mode,the function is also adopted in designing the adaptive gain without knowing the disturbance’s upper bound(DUB).Compared to the existing finite-time and fixed-time controllers,the key superiority of the proposed method is that the system can converge to a prescribed arbitrarily small region in predefined time irrespective of the initial *** addition,the control signal is bounded along the settling period,where the settling time instance can be estimated without conservation.

关键词： prescribed designing letter

Enhancing wireless sensing via a target-mounted intelligent reflecting surface

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National Science Review 2023年第8期10卷 13-14页

作者： Xiaodan shao Rui Zhang School of Science and Engineering Shenzhen Research Institute of Big Data The Chinese University of Hong Kong Department of Electrical and Computer Engineering National University of Singapore

An intelligent reflecting surface(IRS),or its various equivalents such as an reconfigurable intelligent surface(RIS), is an emerging technology to control radio signal propagation in wireless systems. An IRS is a digitally controlled metasurface consisting of a large number of passive reflecting elements, which are connected to a smart controller to enable dynamic adjustments of the amplitude and/or phase of the incident signal on each element independently [1].

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Infiltration characteristics of non-aqueous phase liquids in undisturbed loessal soil cores

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Journal of Environmental Sciences 2009年第10期21卷 1424-1431页

作者： WANG Yunqiang shao Ming'an State Key Laboratory of Soil Erosion and Dry-land Farming on the Loess Plateau Institute of Soil and Water Conservation Chinese Academy of Sciences Northwest A&F University Yangling 712100 China. Graduate University of Chinese Academy of Sciences Beijing 100049 China

The widespread contamination of soils and aquifers by non-aqueous phase liquids （NAPL）, such as crude oil, poses serious environmental and health hazards globally. Understanding the infiltration characteristics of NAPL in soil is crucial in mitigating or remediating soil contamination. The infiltration characteristics of crude and diesel oils into undisturbed loessal soil cores, collected in polymethyl methacrylate cylindrical columns, were investigated under a constant fluid head （3 era） of either crude oil or diesel oil. The infiltration rate of both crude and diesel oils decreased exponentially as wetting depth increased with time. Soil core size and bulk density both had significant effects on NAPL infiltration through the undisturbed soil cores; a smaller core size or a greater bulk density could reduce oil penetration to depth. Compacting soil in areas susceptible to oil spills may be an effective stratage to reduce contamination. The infiltration of NAPL into soil cores was spatially anisotropic and heterogeneous, thus recording the data at four points on the soil core is a good stratage to improve the accuracy of experimental results. Our results revealed that crude and diesel oils, rather than their components, have a practical value for remediation of contaminated loessal soils.

关键词： crude oil diesel oil soil compaction soil core sample size the Loess Plateau of China

Challenges for China's medical education in the coming post-COVID-19 era

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National Science Review 2020年第10期7卷 1617-1621页

作者： Li shao Weijie Zhao Department of Education of Shanghai Jiao Tong University School of Medicine

The year of 2020 has been overshadowed by the COVID-19 pandemic. Medical workers throughout China have played critical roles in battling severe acute respiratory syndrome-coronavirus 2(SARS-Co V-2) and saving *** whole of society has now fully realized the significance of medical workers and many began to think about medical education in China: How can we further improve medical education for the next generation of clinicians,

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Robust H_∞ control for networked control systems

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Journal of Systems Engineering and Electronics 2008年第5期19卷 1003-1009页

作者： Ma Weiguo shao Cheng Inst. of Advanced Control Technology School of Electronic and Information Engineering Dalian Univ. of Technology Dalian 116024 P. R. China

The robust H∞ control for networked control systems with both stochastic network-induced delay and data packet dropout is studied. When data are transmitted over network, the stochastic data packet dropout process can be described by a two-state Markov chain. The networked control systems with stochastic network-induced delay and data packet dropout are modeled as a discrete time Markov jump linear system with two operation modes. The sufficient condition of robust H∞ control for networked control systems stabilized by state feedback controller is presented in terms of linear matrix inequality. The state feedback controller can be constructed via the solution of a set of linear matrix inequalities. An example is given to verify the effectiveness of the method proposed.

关键词： networked control systems H∞ control Markov jump linear systems linear matrix inequality.

Robust predictive control of polytopic uncertain systems with both state and input delays

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Journal of Systems Engineering and Electronics 2007年第3期18卷 616-621页

作者： Lu Mei shao Huihe Inst. of Automation Shanghai Jiaotong Univ. Shanghai 200030 P. R. China

A robust model predictive control algorithm for discrete linear systems with both state and input delays subjected to constrained input control is presented, where the polytopic uncertainties exist in both state matrices and input matrices. The algorithm optimizes an upper bound with respect to a state feedback control law. The feedback control law is presented based on the construction of a parameter-dependent Lyapunov function. The above optimization problem can be formulated as a LMI-based optimization. The feasibility of the optimization problem guarantees that the algorithm is robustly stable. The simulation results verify the effectiveness of the proposed algorithm.

关键词： predictive control robust control time-delay system linear matrix inequality.

Tests of gravitational symmetries with radio pulsars

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Science China(Physics,Mechanics & Astronomy) 2016年第9期59卷 10-32页

作者： LiJing shao Norbert Wex Max Planck Institute for Gravitational Physics (Albert Einstein Institute) Potsdam-Golm D-14476 Germany School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 China Max-Planck-Institut fur Radioastronomie Bonn D-53121 Germany

Symmetries play important roles in modern theories of physical laws. In this paper, we review several experimental tests of important symmetries associated with the gravitational interaction, including the universality of free fall for self-gravitating bodies,time-shift symmetry in the gravitational constant, local position invariance and local Lorentz invariance of gravity, and spacetime translational symmetries. Recent experimental explorations for post-Newtonian gravity are discussed, of which, those from pulsar astronomy are highlighted. All of these tests, of very different aspects of gravity theories, at very different length scales, favor to very high precision the predictions of the strong equivalence principle(SEP) and, in particular, general relativity which embodies SEP completely. As the founding principles of gravity, these symmetries are motivated to be promoted to even stricter tests in future.

关键词： gravitation radio pulsars spacetime symmetry

Estimation in Discrete Reliability Growth,a Growth Model with Coefficient Condition

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Journal of Systems Science & Complexity 2016年第4期29卷 1112-1122页

作者： shao Xiang FANG Xiangzhong School of Mathematics Science Peking UniversityBeijing 100871China

This paper considers the well known problem of estimating reliability in discrete reliability growth context with sequence of dichotomous success-failure outcomes. More precisely, the authors generalize the simple order relationship constraint with some coefficients. The authors prove that under some mild conditions, the generalized constraint MLE problem can be transformed to a traditional isotonic problem. The authors also study the lower confidence limit estimation of reliability with sample space ranking method. A simulation is conducted to illustrate the superiority of the proposed method.

关键词： Confidence limit discrete reliability growth isotonic regression point estimation

Approximate Conditional Likelihood for Generalized Linear Models with General Missing Data Mechanism

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Journal of Systems Science & Complexity 2017年第1期30卷 139-153页

作者： ZHAO Jiwei shao Jun Department of Biostatistics State University of New York at Buffalo School of Statistics East China Normal University

The generalized linear model is an indispensable tool for analyzing non-Gaussian response data, with both canonical and non-canonical link functions comprehensively used. When missing values are present, many existing methods in the literature heavily depend on an unverifiable assumption of the missing data mechanism, and they fail when the assumption is violated. This paper proposes a missing data mechanism that is as generally applicable as possible, which includes both ignorable and nonignorable missing data cases, as well as both scenarios of missing values in response and *** this general missing data mechanism, the authors adopt an approximate conditional likelihood method to estimate unknown parameters. The authors rigorously establish the regularity conditions under which the unknown parameters are identifiable under the approximate conditional likelihood approach. For parameters that are identifiable, the authors prove the asymptotic normality of the estimators obtained by maximizing the approximate conditional likelihood. Some simulation studies are conducted to evaluate finite sample performance of the proposed estimators as well as estimators from some existing methods. Finally, the authors present a biomarker analysis in prostate cancer study to illustrate the proposed method.

关键词： Asymptotic normality generalized linear model identifiability missing data mechanism,non-canonical link function nonignorable missingness.