Python之禅(英文)

Beautiful is better than ugly. Explicit is better than implicit, Simple is better than complex. Complex is better than complicated Flat is better than nested. Sparse is better than dense. Readability counts.     

Boundary feedback stabilization of a Schr$\＂{o}$dinger equation interconnected with a heat equation

In this paper, we study stabilization for a Schoedinger equation, which is interconnected with a heat equation via boundary coupling. A direct boundary feedback control is adopted. By a detailed spectral analysis, it is found that there are two branches of eigenvalues： one is along the negative real axis, and the other is approaching to a vertical line, which is parallel to the imagine axis. Moreover, it is shown that there is a set of generalized eigenfunctions, which forms a Riesz basis for the energy state space. Finally, the spectrum-determined growth condition is held and the exponential stability of the system is then concluded.     

Identification of FIR systems under difference-driven scheduled quantized observations

In networked system identification, how to effectively use communication resources and improve convergence speed is the focus of attention. However, there is an inherent contradiction between the two tasks. In this paper, the event-driven communication is used to save communication resources for the identification of finite impulse response systems, and the input design is carried out to meet the requirements of convergence speed. First, a difference-driven communication is proposed. Then, the performance of the communication mechanism is analyzed, and the calculation method of its communication rate is given. After that, according to the communication rate and the convergence rate of the identification algorithm, the input design problem is transformed into a constrained optimization problem, and the algorithm for finding the optimal solution is given. In addition, considering the case that the output is quantized by multiple thresholds, the way to calculate its communication rate is given and the influence of threshold number on communication rate is discussed. Finally, the effectiveness of the algorithm is verified by simulation.     

Modeling and Solving Human Arm’s Posture in Reachablity Analysis

Reachability is a key criterion in maintenance design, and human arm is the main object in reachability analysis. The human arm’s DOF is reduced, and applying military standards and human physiological constraints, the simplified arm model of 7-DOF using D-H method is built up. Particle Swarm Optimization (PSO) is used to acquire the shoulder, arm and hand posture with adaptive fitness function. A detailed reachability analysis is accomplished for disassembling the bolts from crank shaft is given as an exam...     

The kinematic analyses of the 3-DOF parallel machine tools

A 3-degree-of-freedom (3-DOF) parallel machine tool based on a tripod mechanism is developed and studied. The kinematics analysis is performed, the workspace is derived, and an analysis on the number of conditions of the Jacobian matrix and manipulability is carried out. A method for error analysis and manipulability is introduced. Hence, the manipulability analysis of the parallel machine tool is accomplished.     

Constructing C~1 Continuous Surface on Irregular Quad Meshes

A new method is proposed for surface construction on irregular quad meshes as extensions to uniform B-spline surfaces. Given a number of control points, which form a regular or irregular quad mesh, a weight function is constructed for each control point. The weight function is defined on a local domain and is C1 continuous. Then the whole surface is constructed by the weighted combination of all the control points. The property of the new method is that the surface is defined by piecewise Cl bi-cubic rational parametric polynomial with each quad face. It is an extension to uniform B-spline surfaces in the sense that its definition is an analogy of the B-spline surface, and it produces a uniform bi-cubic B-spline surface if the control mesh is a regular quad mesh. Examples produced by the new method are also included.     

A new knowledge reduction algorithm for information system

The discernible Boolean matrix of information system is defined. The model of attribute reduction in the form of linear logical equations is established. The necessary and sufficient condition for determining whether the attribute is absolutely necessary, relatively necessary and absolutely superfluous is given. Finally, an elementary knowledge reduction algorithm is proposed.     

分层自组织耦合振荡聚类方法

A self-organization of pulse-coupled oscillators for clustering method is studied and the defectiveness of the method is analyzed.With modification to the method a new clustering method is presented.Experiments indicate the modified method is effective.     

Neural model-based adaptive control for systems with unknown Preisach-type hysteresis

An adaptive control scheme is presented for systems with unknown hysteresis. In order to handle the case where the hysteresis output is unmeasurale, a novel model is firstly developed to describe the characteristic of hysteresis. This model is motivated by Preisach model but implemented by using neural networks (NN). The main advantage is that it is easily used for controller design. Then, the adaptive controller based on the proposed model is presented for a class of SISO nonlinear systems preceded by unknown hysteresis, which is estimated by the proposed model. The hws for model updating and the control hws for the neural adaptive controller are derived from Lyaptmov stability theorem, therefore the semi - global stability of the closed-loop system is guaranteed. At last, the simulation results are illuswated.     

An Algorithm for Determining Database Consistency Under the Closed World Assumption

It is well-known that there are circumstances where applying Reiter's closed world assump-tion (CWA) will lead to logical inconsistencies . In this paper, a new characterization of theCWA consistency is pesented and an algorithm is proposed for determining whether a datalase with-out function symbols is consistent with the CWA. The algorithm is shown to be efficient.     

The Complexity of Recognition in the Single-Layered PLN Network with Feedback Connections

Regarding a single-layered PLN network with feedback connections as an associative memory network,the complexity of recognitions is discussed.We have the main result:if the size of the network N is m,then the complexity of recognition is an exponential function of m.The necessary condition under which the complexity of recognition is polynomial is given.     

基于杂波特性的自动跟踪起始试验统计方法

Two test statistics based on clutter characteristics are derived. A tentative track is confirmed when the track-is-on-clutter hypothesis is rejected. A constant and known false track rate results when the assumptions of the null hypothesis are true. The first test statistic is based on the clutter density. A high probability of target detection is resulted when the expected distance to the nearest target peak is less than the expected distance to the nearest clutter peak. The second test statistic is based on the clutter amplitude. A high probability of target detection is resulted when the expected amplitude of the target peak is greater than the expected amplitude of clutter peaks. The behavior of the clutter-based test statistics is compared with the target visibility method, using simulated data. All track initiation methods are applied using a track updater based on probabilistic data association (PDA), extended to incorporate peak amplitude information, which is available.     

同时镇定一族带有不确定参数的多输入非线性系统

Simultaneous stabilization for a collection of multi-input nonlinear systems with uncertain parameters is dealt with in this paper. A systematic method for obtaining a control Lyapunov function (CLF) is presented by solving the Lyapunov equation. A sufficient condition that a quadratic CLF is a common CLF for these systems is acquired. A continuous state feedback is designed to simultaneously stabilize these systems. Finally, the effectiveness of the proposed scheme is illustrated by a simulation example.     

Sliding mode control with disturbance observer for a class of nonlinear systems

This paper is concerned with the stabilization problem for a class of nonlinear systems with disturbance. The disturbance model is unknown and the first derivative of disturbance is bounded. Firstly, a general disturbance observer is proposed to estimate disturbance approximatively. Secondly, since the bound of the disturbance observer error is unknown, an adaptive sliding mode controller is designed to guarantee that the state of system asymptotically converges to zero and the unknown bound can be adjusted by an adaptive law. Finally, an example is given to illustrate the effectiveness of the proposed method.     

Stability analysis for an Euler-Bernoulli beam under local internal control and boundary observation

An Euler-Bernoulli beam system under the local internal distributed control and boundary point observation is studied. An infinite-dimensional observer for the open-loop system is designed. The closed-loop system that is non- dissipative is obtained by the estimated state feedback. By a detailed spectral analysis, it is shown that there is a set of generalized eigenfunctions, which forms a Riesz basis for the state space. Consequently, both the spectrum-determined growth condition and exponential stability are concluded.     

Function Definition Language FDL and its implementation

A Function Definition Language(FDL)is presented.Though designed for describing specifications.FDL is also a general-purpose functional programming language.It uses context-free language as data type,supports pattern matching definition of functions,offers several function definition forms,and is executable.It is shown that FDL has strong expressiveness,is easy to use and describes algorithms concisely and naturally.An interpreter of FDL is introduced.Experiments and discussion are included.     

Normalized Exponential Neural Networks

In this paper,the normalized exponential neural network(ENN)is studied.It is proved that ENN is a universal approximator.The stability relation between systems and neural networks working as controllers is investigated.The results show that when designing a system,one should firstly Consider system stability rather than controller stability,Accordingly,a new hybrid learning algorithm is presented,and it is proved that this algorithm eventually converge to equilibria.     

REMARKS ON JOHN DISKS

Let D■R2 be a Jordan domain,D*=R2\D,the exterior of D.In this article,the authors obtained the following results:(1)If D is a John disk,then D is an outer linearly locally connected domain;(2)If D* is a John disk,then D is an inner linearly locally connected domain;(3)A homeomorphism f:R 2 →R 2 is a quasiconformal mapping if and only if f(D)is a John disk for any John disk D■R 2 ;and(4)If D is a bounded quasidisk,then D is a John disk,and there exists an unbounded quasidisk which is not a John disk.     

采样系统鲁棒稳定性分析的新方法

The lifting technique is now the most popular tool for dealing with sampled-data control systems. However, for the robust stability problem the system norm is not preserved by the lifting as expected. And the result is generally conservative under the small gain condition. The reason for the norm difference by the lifting is that the state transition operator in the lifted system is zero in this case. A new approach to the robust stability analysis is proposed. It is to use an equivalent discrete-time uncertainty to replace the continuous-time uncertainty. Then the general discretized method can be used for the robust stability problem, and it is not conservative. Examples are given in the paper.     

Fixed-parameter tractability of disjunction-free default reasoning

In this paper,the parameter which is the source of the complexity of disjunctionfree default reasoning is determined.It is shown that when the value of this parameter is fixed,the disjunction-free default reasoning can be solved time bounded by a polynomial whose degree does not depend on the parameter.Consequently,disjunction-free default reasoning is fixed parameter tractable.