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Acta Mathematica Scientia 2018年第6期38卷 1655-1677页

作者： zhipeng zhang Institute of Applied Physics and Computational Mathematics Beijing 100088 China Department of Mathematics Nanjing University Nanjing 210093 China

In this paper, we establish the existence of the global weak solutions for the non-homogeneous incompressible magnetohydrodynamic equations with Navier boundary condi-tions for the velocity field and the magnetic field in a bounded domain Ω R^3. Furthermore,we prove that as the viscosity and resistivity coefficients go to zero simultaneously, these weaksolutions converge to the strong one of the ideal nonhomogeneous incompressible magneto-hydrodynamic equations in energy space.

关键词： nonhomogeneous incompressible MHD equations Navier boundary conditions Inviscid and non-resistive limit

Higher-order properties and extensions for indirect MRAC and APPC of linear systems

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Science China(Information Sciences) 2024年第4期67卷 218-238页

作者： Yanjun zhang zhipeng zhang Jian SUN Lei WANG Kangkang zhang National Key Lab of Autonomous Intelligent Unmanned Systems Beijing Institute of Technology Beijing Institute of Technology Chongqing Innovation Center College of Control Science and Engineering Zhejiang University Department of Electrical and Electronic Engineering Imperial College London KIOS Research and Innovation Center of Excellence University of Cyprus

Recently, a reference derived some new higher-order output tracking properties for direct model reference adaptive control(MRAC) of linear time-invariant(LTI) systems: limt→∞ e~((i))(t) = 0, i = 1,..., n~*-1, where n~* and e~((i))(t) denote the relative degree of the system and the i-th derivative of the output tracking error, respectively. However, a naturally arising question involves whether indirect adaptive control(including indirect MRAC and indirect adaptive pole placement control) of LTI systems still has higher-order tracking properties. Such properties have not been reported in the literature. Therefore, this paper provides an affirmative answer to this question. Such higher-order tracking properties are new discoveries since they hold without any additional design conditions and, in particular, without the persistent excitation condition. Given the higher-order properties, a new adaptive control system is developed with stronger tracking features.(1) It can track a reference signal with any order derivatives being unknown.(2) It has higher-order exponential or practical output tracking properties.(3) Finally, it is different from the usual MRAC system, whose reference signal’s derivatives up to the n~* order are assumed to be known. Finally, two simulation examples are provided to verify the theoretical results obtained in this paper.

关键词： higher-order tracking indirect adaptive control model reference adaptive control adaptive pole placement control

Multi-step state-based opacity for unambiguous weighted machines

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Science China(Information Sciences) 2024年第11期67卷 211-221页

作者： zhipeng zhang Chengyi XIA Guoyuan QI Jun FU School of Artificial Intelligence Tiangong University School of Control Science and Engineering Tiangong University State Key Laboratory of Synthetical Automation for Process Industries Northeastern University

Opacity is a central concept in the issue of privacy security and has been studied extensively in fields such as finite automata, probabilistic automata, and stochastic automata. Here, we investigate the problem of validating multi-step opaque properties through unambiguous weighted machines from the perspective of cyber-physical systems. First, the notion of multi-step state-based opacity for unambiguous weighted machines is presented and defined. It includes two variants of delays with a finite K and infinite steps. Subsequently, the weighted state estimate with K(infinite)-step delay is established by abstracting the possible state set that the system could have through these weighted observations. Meanwhile, to keep the observable weighted sequence consistent between the bidirectional observers, the unobserved weights of the reverse weighted machine are assumed to be reserved. Subsequently, the existence conditions are developed, and the corresponding algorithms, termed the weighted bidirectional observer, are generalized to verify these properties. Finally, several numerical examples are illustrated to demonstrate the effectiveness of the proposed method. Taken together, the current approach will be conducive to a deep understanding of the security and privacy of cyber-physical systems.

关键词： logical dynamical systems weighted state machine state estimation opacity cyber physical systems

Compatible-invariant subset analysis of deterministic finite automata via semi-tensor product of matrices approach

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The Journal of China Universities of Posts and Telecommunications 2018年第5期25卷 75-82页

作者： zhang zhipeng Chen Zengqiang Liu Zhongxin College of Computer and Control Engineering Nankai University Tianjin Key Laboratory of Intelligent Robotics Nankai University

The compatible-invariant subset of deterministic finite automata（ DFA） is investigated to solve the problem of subset stabilization under the frameworks of semi-tensor product（ STP） of matrices. The concepts of compatibleinvariant subset and largest compatible-invariant subset are introduced inductively for Moore-type DFA,and a necessary condition for the existence of largest compatible-invariant subset is given. Meanwhile,by using the STP of matrices,a compatible feasible event matrix is defined with respect to the largest compatible-invariant *** on the concept of compatible feasible event matrix,an algorithm to calculate the largest compatible-invariant subset contained in a given subset is proposed. Finally,an illustrative example is given to validate the results.

关键词： discrete event dynamical systems (DEDSs) finite automata compatible iuvariant semi-tensor product (STP) compatible feasible eventmatrix

ZERO KINEMATIC VISCOSITY-MAGNETIC DIFFUSION LIMIT OF THE INCOMPRESSIBLE VISCOUS MAGNETOHYDRODYNAMIC EQUATIONS WITH NAVIER BOUNDARY CONDITIONS

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Acta Mathematica Scientia 2021年第5期41卷 1503-1536页

作者： Fucai LI zhipeng zhang Department of Mathematics Nanjing UniversityNanjing 210093China Institute of Applied Physics and Computational Mathematics Beijing 100088China

We investigate the uniform regularity and zero kinematic viscosity-magnetic diffusion limit for the incompressible viscous magnetohydrodynamic equations with the Navier boundary conditions on the velocity and perfectly conducting conditions on the magnetic field in a smooth bounded domain Ω⊂R^(3).It is shown that there exists a unique strong solution to the incompressible viscous magnetohydrodynamic equations in a finite time interval which is independent of the viscosity coefficient and the magnetic diffusivity *** solution is uniformly bounded in a conormal Sobolev space and W^(1,∞)(Ω)which allows us to take the zero kinematic viscosity-magnetic diffusion ***,we also get the rates of convergence in L^(∞)(0,T;L^(2)),L^(∞)(0,T;W^(1,p))(2≤p0.

关键词： incompressible viscous MHD equations ideal incompressible MHD equations Navier boundary conditions zero kinematic viscosity-magnetic diffusion limit

Modeling and reachability of probabilistic finite automata based on semi-tensor product of matrices

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Science China(Information Sciences) 2018年第12期61卷 202-204页

作者： zhipeng zhang Zengqiang CHEN Zhongxin LIU College of Computer and Control Engineering Nankai University Tianjin Key Laboratory of Intelligent Robotics Nankai University

Dear editor,As mathematical models, finite automata have been a powerful synthesis tool for modeling and analyzing discrete event systems where states and events are a finite logical or discrete set. In deterministic finite automata, the successor can be uniquely determined by the predecessor and input event. In other words, it exhibits a deterministic behavior. As a practical and theoretical motivation, probabilistic finite automata (PFAs)

关键词： Modeling and reachability of probabilistic finite automata based on semi-tensor product of matrices

Molecular dynamics study of water molecules nucleation for fine particle removal:Effects of wettability and aggregation modes and comparison with experiment Author links open overlay panel

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Particuology 2024年第8期91卷 106-117页

作者： Junchao Xu zhipeng zhang Li Lv Yunfei zhang Yiming Xie Huaqiang Chu School of Energy and Environment Anhui University of TechnologyMaanshan243002China College of Mechanical and Electrical Engineering China Jiliang UniversityHangzhou310018China

Water vapor nucleation on particle's surface plays an important role in dust removal,cloud formation,and particle ***,the selectivity of nucleation sites and the nucleation characteristic of water molecule on the particle's surface are still unclear,especially for the aggregated *** this paper,the effects of particle wettability and aggregation modes on the selectivity of nucleation sites and the nucleation characteristics were investigated using molecular dynamics *** results were compared with our earlier experimental *** illustrates how the contact angle of clusters,the growth velocity,and the growth duration are all influenced by the interaction coefficient between water and ***,the nucleation sites of water molecules on the particle aggregation surface exhibit a definite *** primary indicator of this selectivity is the preferential nucleation of water molecules at the interfaces of linear chain aggregation particles,at the inner side of non-linear chain aggregation particles,and at the centers of ring *** results are in good agreement with our previous experimental *** significantly,additional research has revealed that subcritical-size clusters typically aggregate on two-particle surfaces spacing when the spacing smaller than the critical cluster size.

关键词： Heterogeneous nucleation Water molecule Wettability Aggregation modes Molecule dynamics

Effect of saline water ionic strength on phosphorus recovery from synthetic swine wastewater

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Journal of Environmental Sciences 2022年第3期34卷 81-91页

作者： zhipeng zhang Bing Li Filicia Wicaksana Wei Yu Brent Young Department of Chemical&Materials Engineering University of AucklandAuckland 1010New Zealand

Declining worldwide phosphate rock reserves has driven a growing interest in exploration of alternative phosphate supplies. This study involved phosphorus recovery from swine wastewater through precipitation of struvite, a valuable slow-release fertiliser. The economic feasibility of this process is highly dependent on the cost of magnesium source. Two different magnesium sources were used for phosphorus recovery: pure magnesium chloride and nanofiltration(NF) saline water retentate. The paper focuses on the impact of ionic strength on phosphorus recovery performance that has not been reported elsewhere. Experimental design with five numerical variables(Mg/P molar ratio, pH, PO_(4)^(3-)-P, NH_(4)^(+)-N, and Ca^(2+) levels) and one categorical variable(type of magnesium source) was used to evaluate the effect of ionic strength on phosphorus removal and struvite purity. The experimental data were analysed using analysis of variance(ANOVA) and principal component analysis(PCA). Results indicated that a magnesium source obtained from NF retentate was as effective as MgCl_(2) for struvite precipitation. It was also revealed that ionic strength had a more positive effect on struvite purity than on phosphorus removal. Within the range of parameters studied in this research, high ionic strength, high p H and wastewater with high phosphate, high ammonium and low calcium contents were found to be the most favourable conditions for struvite precipitation. Findings from this study will be beneficial to determine the feasibility of using high ionic strength saline water, such as NF seawater retentate, as a magnesium source for phosphorus recovery from wastewater that is rich in ammoniumnitrogen and phosphate.

关键词： Phosphorus recovery Struvite Ionic strength Wastewater Nanofiltration retentate

Strong fault prognosability of partially-observed discrete event systems

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Science China(Information Sciences) 2023年第3期66卷 301-302页

作者： Yingrui ZHOU Zengqiang CHEN Zhongxin LIU zhipeng zhang College of Artificial Intelligence Nankai University School of Computer Science and Engineering Tianjin University of Technology

Dear editor, As an important model to analyze cyber-physical systems,the study of discrete event systems has always been prevailing [1–4]. Especially, the problem of fault prognosis becomes a crucial subject for its applications in security and maintenance [5]. In decentralized fault prognosis, the given system can be monitored by several agents and each agent sends its local observation to the global prognoser,

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Multi-UAV Collaborative Mission Planning Method for Self-Organized Sensor Data Acquisition

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Computers, Materials & Continua 2024年第10期81卷 1529-1563页

作者： Shijie Yang Jiateng Yuan zhipeng zhang Zhibo Chen Hanchao zhang Xiaohui Cui School of Information Science and Technology Beijing Forestry UniversityBeijing100083China Engineering Research Center for Forestry-Oriented Intelligent Information Processing of National Forestry and Grassland Administration Beijing100083China State Key Laboratory of Efficient Production of Forest Resources Beijing100083China Division of Biostatistics Department of Population HeathGrossman School of MedicineNew York UniversityNew YorkNY 10016USA

In recent years,sensor technology has been widely used in the defense and control of sensitive areas in cities,or in various scenarios such as early warning of forest fires,monitoring of forest pests and diseases,and protection of endangered *** sensors to collect data and then utilizing unmanned aerial vehicle(UAV)to collect the data stored in the sensors has replaced traditional manual data collection as the dominant *** current strategies for efficient data collection in above scenarios are still imperfect,and the low quality of the collected data and the excessive energy consumed by UAV flights are still the main problems faced in data *** regards this,this paper proposes a multi-UAV mission planning method for self-organized sensor data acquisition by comprehensively utilizing the techniques of self-organized sensor clustering,multi-UAV mission area allocation,and sub-area data acquisition scheme *** improvedα-hop clustering method utilizes the average transmission distance to reduce the size of the collection sensors,and the K-Dimensional method is used to form a multi-UAV cooperative workspace,and then,the genetic algorithm is used to trade-off the speed with the age of information(AoI)of the collected information and the energy consumption to form the multi-UAV data collection operation *** combined optimization scheme in paper improves the performance by 95.56%and 58.21%,respectively,compared to the traditional baseline *** order to verify the excellent generalization and applicability of the proposed method in real scenarios,the simulation test is conducted by introducing the digital elevation model data of the real terrain,and the results show that the relative error values of the proposed method and the performance test of the actual flight of the UAV are within the error interval of±10%.Then,the advantages and disadvantages of the present method with the existing mainstream schemes are tested,and

关键词： Unmanned aerial vehicle sensor self-organization path planning multi-UAV task assignment