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Self-adaptive learning based discrete differential evolution algorithm for solving CJWTA problem

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Journal of Systems Engineering and Electronics 2014年第1期25卷 59-68页

作者： Yu Xue Yi Zhuang Tianquan ni Siru ni Xuezhi Wen College of Computer Science and Technology Nanjing University of Aeronautics and Astronautics School of Computer and Software Nanjing University of Information Science and Technology No.723 Research Institute of China Shipbuilding Industry Corporation

Cooperative jamming weapon-target assignment （CJWTA） problem is a key issue in electronic countermeasures （ECM）. Some symbols which relevant to the CJWTA are defined firstly. Then, a formulation of jamming fitness is presented. Final y, a model of the CJWTA problem is constructed. In order to solve the CJWTA problem efficiently, a self-adaptive learning based discrete differential evolution （SLDDE） algorithm is proposed by introduc-ing a self-adaptive learning mechanism into the traditional discrete differential evolution algorithm. The SLDDE algorithm steers four candidate solution generation strategies simultaneously in the framework of the self-adaptive learning mechanism. Computa-tional simulations are conducted on ten test instances of CJWTA problem. The experimental results demonstrate that the proposed SLDDE algorithm not only can generate better results than only one strategy based discrete differential algorithms, but also outper-forms two algorithms which are proposed recently for the weapon-target assignment problems.

关键词： global optimization self-adaptive discrete differentialevolution weapon-target assignment (WTA) cooperative jamming.

Parametric study on supersonic flutter of angle-ply laminated plates using shear deformable finite element method

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Acta Mechanica Sinica 2011年第5期27卷 749-756页

作者： Wei Xia Qiao ni School of Civil Engineering and Mechanics Huazhong University of Science and Technology430074 Wuhan China MOE Key Laboratory for Strength and VibrationSchool of Aerospace Xi＇an Jiaotong University710049 Xi＇an China

The influence of fiber orientation,flow yaw angle and length-to-thickness ratio on flutter characteristics of angle-ply laminated plates in supersonic flow is studied by finite element *** structural model is established using the Reissner-Mindlin theory in which the transverse shear deformation is *** aerodynamic pressure is evaluated by the quasi-steady first-order piston *** equations of motion are formulated based on the principle of virtual *** the harmonic motion assumption,the flutter boundary is determined by solving a series of complex eigenvalue *** study shows that （1） The flutter dynamic pressure and the coalescence of flutter modes depend on fiber orientation,flow yaw angle and length-to-thickness ratio;（2） The laminated plate with all fibers aligned with the flow direction gives the highest flutter dynamic pressure,but a slight yawing of the flow from the fiber orientation results in a sharp decrease of the flutter dynamic pressure;（3） The angle-ply laminated plate with fiber orientation angle equal to flow yaw angle gives high flutter dynamic pressure,but not the maximum flutter dynamic pressure;（4） With the decrease of length-to-thickness ratio,an adverse effect due to mode transition on the flutter dynamic pressure is found.

关键词： Panel flutter Angle-ply laminates Fiber orientation Flow yaw angle Length-to-thickness ratio

Uniqueness of PL Minimal Surfaces

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Acta Mathematica Sinica,English Series 2007年第6期23卷 961-964页

作者： Yi ni Department of Mathematics Princeton University Princeton New Jersey 08544

Using a standard fact in hyperbolic geometry, we give a simple proof of the uniqueness of PL minimal surfaces, thus filling in a gap in the original proof of Jaco and Rubinstein. Moreover, in order to clarify some ambiguity, we sharpen the definition of PL minimal surfaces, and prove a technical lemma on the Plateau problem in the hyperbolic space.

关键词： PL minimal surface hyperbolic geometry Plateau problem

STABILIZATION OF SWITCHED LINEAR SYSTEMS WITH CONSTRAINED INPUTS

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Journal of Systems Science & Complexity 2012年第1期25卷 60-70页

作者： Wei ni Daizhan CHENG Department of Mathematics School of ScienceNanchang University Key Laboratory of Systems and Control Institute of Systems ScienceChinese Academy of Sciences

The stabilization of switched linear systems with constrained inputs （SLSCI） is considered. The authors design admissible linear state feedbacks and the switching rule which has a minimal dwell time （MDT） to stabilized the system. First, for each subsystem with constrained inputs, a stabilizing linear state feedback and an invariant set of the closed-loop system are simultaneously constructed, such that the input constraints are satisfied if and only if the closed-loop system＇s states lie inside this set. Then, by constructing a quadratic Lyapunov function for each closed-loop subsystem, an MDT is deduced and an MDT-based switching strategy is presented to ensure the stability of the switched system.

关键词： Constrained inputs dwell time stabilization switched linear system.

Solutions without a maximum mass limit of the general relativistic field equations for neutron stars

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Science China(Physics,Mechanics & Astronomy) 2011年第7期54卷 1304-1308页

作者： ni Jun Department of Physics Tsinghua University Beijing 100084 China

We have investigated the general relativistic field equations for neutron *** find that there are solutions for the equilibriummass distribution without a maximum mass *** solutions correspond to stars with a void inside their *** thesesolutions,the mass density and pressure increase first from zero at the inner radius to a peak and then decrease to zero at the *** the change of the void boundary,the mass and particle number of the star can approach *** stars withlarge masses can remain stable and do not collapse into black holes.

关键词： neutron stars Tolman-Oppenheimer-Volkoff equations general relativistic field equations

Introduction to advances in the study of supercritical geofluids

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Science China Earth Sciences 2023年第10期66卷 2391-2394页

作者： Huaiwei ni School of Earth and Space Sciences University of Science and Technology of ChinaHefei230026China Key Laboratory of Crust-Mantle Materials and Environments&Center for Excellence in Comparative Planetology Chinese Academy of SciencesHefei230026China

The role of supercritical geofluids has received increasing attention in frontier research of geological processes in the deep Earth(ni,2020).Supercritical geofluids(hereafter referred to as supercritical fluids)are a special type of fluids permitted by complete miscibility between rock components(e.g.,silicates,carbonates,and sulfates)and water under high conditions of temperature and pressure.

关键词： fluids hereafter frontier

Modeling of solid oxide fuel cells

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Science Bulletin 2016年第17期61卷 1311-1312页

作者： Meng ni Department of Building and Real Estate The Hong Kong Polytechnic University

Solid oxide fuel cell(SOFC)is a high temperature(800-1000℃)power source,which can directly convert the chemical energy of a fuel into electrical energy via electrochemical *** the energy conversion process is straightforward,the electric efficiency of SOFC(>50%)is considerably higher than that of conventional heat engines(<40%).Compared with low temperature fuel cells,such as proton exchange membrane fuel

关键词： SOFC considerably proton PEMFC stack convert electrolysis alkaline battery kinetics

Extension of Isometries on the Unit Sphere of L^p Spaces

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Acta Mathematica Sinica,English Series 2012年第6期28卷 1197-1208页

作者： Dong ni TAN Department of Mathematics Tianjin University of Technology School of Mathematical Science Nankai University

In this paper we study the isometric extension problem and show that every surjective isometry between the unit spheres of L^p（μ）（1 〈 p 〈∞, p ≠ 2） and a Banach space E can be extended to a linear isometry from L^p（μ） onto E, which means that if the unit sphere of E is （metrically） isometric to the unit sphere of L^P（μ）, then E is linearly isometric to L^p（μ）. We also prove that every surjective 1-Lipschitz or anti-l-Lipschitz map between the unit spheres of L^p（μ1, H1） and L^p（μ2, H2） must be an isometry and can be extended to a linear isometry from L^p（μ2, H2） to L^p（μ2, H2）, where H1 and H2 are Hilbert spaces.

关键词： Tingley's problem 1-Lipschitz anti-l-Lipschitz isometry isometric extension

Output Feedback H~∞ Control for a Class of Nonlinear Stochastic Systems

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Acta Mathematicae Applicatae Sinica 2010年第2期26卷 251-266页

作者： Yuan-Hua ni Key Laboratory of Systems and Control Institute of Systems Science Academy of Mathematics and SystemsScience Chinese Academy of Sciences Beijing 100190 China

This paper deals with the output feedback H∞ control problem for a class of nonlinear stochastic systems. Based on the latest developed theory of stochastic dissipation, a notable result about the nonlinear H∞ output feedback control of deterministic system is generalized to the stochastic case. Finally, in the cases of state feedback and output feedback, two families of controllers are provided respectively.

关键词： H∞ control stochastic nonlinear systems Hamilton-Jacobi-Isaacs equations output feedback