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Search Results: 1 - 10 of 80848 matches for " XingHua Liu "
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Study on Delaunay Triangulation with the Islets Constraints  [PDF]
Dong Wei, Xinghua Liu
Intelligent Information Management (IIM) , 2010, DOI: 10.4236/iim.2010.26045
Abstract: Aiming at Delaunay triangulation with islets constrains in terrain simulation. A general Delaunay triangulation algorithm for constrained data set with islets is proposed. The algorithm firstly constructs Constrained Delaunay Triangulation with constraint polygons which are inner boundary of islets, then according to topological relations within edge, surface, arc segment, applies bidirectional search to find the triangle in islet, lastly it carries on certain corresponding processing to complete the Delaunay triangulation algorithm with islets. The analyses show the algorithm simple, fast speed. The algorithm can be used in 3-D terrain vision.
Asymptotic Stability Analysis and Optimality Algorithm for Uncertain Neutral Systems with Saturation
Xinghua Liu
ISRN Applied Mathematics , 2014, DOI: 10.1155/2014/805798
Abstract: The certain and uncertain neutral systems with time-delay and saturating actuator are considered in this paper. In order to analyse and optimize the system, auxiliary functions are presented based on additive decomposition approach and the relationship among them is discussed. As the novel stability criterion, two sufficient conditions are obtained for asymptotic stability of the neutral systems. Furthermore, the paper gives the stability analysis algorithm and optimality algorithm to optimize the result. Finally, from the two-stage dissolution tank of solid caustic soda in a chemical plant, three numerical examples are implemented to show the effectiveness of the proposed method. 1. Introduction Delay is often inevitable in various practical systems; examples include population ecology [1], steam or water pipes, heat exchanges [2], and many others [3–5]. In the control engineering language, these delays can be categorized as state delay, input or output delay (retarded systems), delay in the state derivative (neutral systems), and so forth. Guaranteeing the stability of systems with delay is one core design objective both in theory and in practice. Particularly, in terms of neutral systems, the focus has mainly been on systems with identical delays in neutral and discrete terms [6–10]. Results also exist that depend only on the size of the discrete delays but not on the size of the neutral delays [11–13]. Besides delays, the saturated controller is apt to cause instability as well. In the presence of actuator saturation, the problem of estimating asymptotic stability regions for linear systems subject to it has been studied by many researches in the past years in [14]. Generally speaking, the existing methods for estimating the stability regions for linear systems with saturating actuators are based on the concept of Lyapunov level set. LMI optimization-based approaches were proposed to estimate the stability regions by using quadratic Lyapunov functions and the Lur’s-type Lyapunov functions in [15–19]. For the studies in response to both issues of delay and saturation, the sufficient conditions for systems with delay and saturated actuator are obtained in [18, 20–22]; Lyapunov-Krasovskii functional is employed to investigate the delay-dependent robust stabilization for uncertain neutral systems with saturated actuators in [20]; a controller is constructed in terms of linear matrix inequalities using descriptor model transformation in [18], just to name a few. However, this paper wants to provide a new method to find the system stability region and
Stability Analysis for Neutral Delay Markovian Jump Systems with Nonlinear Perturbations and Partially Unknown Transition Rates
Xinghua Liu,Hongsheng Xi
Advances in Mathematical Physics , 2013, DOI: 10.1155/2013/592483
Abstract: The problem of exponential stability for the uncertain neutral Markovian jump systems with interval time-varying delays and nonlinear perturbations is investigated in this paper. This study starts from the corresponding nominal systems with known and partially unknown transition rates, respectively. By constructing a novel augmented Lyapunov functional which contains triple-integral terms and fully utilizes the bound of the delay, the delay-range-dependent and rate-dependent exponential stability criteria are developed by the Lyapunov theory, reciprocally convex lemma, and free weighting matrices. Then, the results about nominal systems are extended to the uncertain case. Finally, numerical examples are given to demonstrate the effectiveness of the proposed methods. 1. Introduction Neutral time-delay systems have been the focus of the research community, which are often encountered in such practical situations as distributed networks, population ecology, processes including steam or heat exchanges [1], and robots in contact with rigid environments [2], and so forth. The existence of time delay may cause the instability of the systems, thus making the stability analysis of time-delay systems an interesting topic. Existing results can be roughly classified into two categories, delay-independent criteria and delay-dependent criteria, where the latter is generally regarded as less conservative. In addition, it should be pointed out that the stability of neutral time-delay systems is more difficult to tackle since the derivative of the delayed state is involved. The situation is similar as singular systems [3, 4], whose stability problem is more complicated than that for regular systems because more factors need to be considered. In the past decades, considerable attention has been devoted to the robust delay-independent stability and delay-dependent stability of linear neutral systems, which are mainly obtained based on the Lyapunov-Krasovskii (L-K) method [5–8]. Furthermore, when nonlinear perturbations or parameter uncertainties appear in neutral systems, some results on stability analysis have been also presented [9–14]. Various techniques have been proposed in these papers, for example, model transformation techniques, the improved bounding techniques, and matrix decomposition approaches. In particular, He et al. [14] propose a new method for dealing with time-delay systems, which employs free weighting matrices to express the relationships between the terms in the Newton-Leibniz formula and has brought novel results. However, many complex systems with
A 1-18GHz MICROSTRIP BALUN DOUBLE BALANCED MIXER
1-18GHz微带巴伦双平衡混频器

Liu Xinghua,
刘兴华

电子与信息学报 , 1988,
Abstract: A multi-octave microstrip balun double balanced mixer has been developed. This mixer which is consisted of a broad-band balun and a diode ring exhibits extremely encouraging performance. Within the multi-octave bandwidth from 1 to 18 GHz, the average DSB noise figure is 6 dB, and the maximum DSB noise figure is 8.7 dB, and both LO-RF and LO-IF isolations are more than 15 dB.
Classification of Single Traveling Wave Solutions to the Generalized Strong Nonlinear Boussinesq Equation without Dissipation Terms in P = 1  [PDF]
Xinghua Du
Journal of Applied Mathematics and Physics (JAMP) , 2014, DOI: 10.4236/jamp.2014.23006
Abstract:

By the complete discrimination system for polynomial method, we obtained the classification of single traveling wave solutions to the generalized strong nonlinear Boussinesq equation without dissipation terms in p=1.

A Study on Classification and Mapping of TM DataSupported by GIS
基于GIS的TM数据分类及辅助制图研究

Liu Xinghua,
刘行华

遥感学报 , 1992,
Abstract: Based on the analysis of TM imagery covering the loess hilly land and desert land, layer classification and GIS-aided classification have been carried out respectively. After fuzzy reasoning and interactive editing of the classification results, the ' pure" remote sensing thematic data can be used as the dynamic information source for updating of GIS data-base, and mapping activities can be done with the help of GIS.
A covering theory of special relativity
Daqing Liu,Xinghua Li,Yanshen Wang
Physics , 2011, DOI: 10.4006/1.3589801
Abstract: Under the assumption of closed-path velocity of light invariant, we show both the general expression of velocity of light in an ordinary inertial reference frame and the generalized Lorentz transformation between the ordinary inertial reference frame and the absolute (privileged) reference frame. Although such assumption can not determine theory ambiguously, some significant results can still be obtained by the assumption. Furthermore, the study shows that the relativity of simultaneity is not a universal concept.
Electronic structure and fluorescent property of endohedral terbium fullerenes
Dayong Sun,Ziyang Liu,Xinghua Guo,Wenguo Xu,Shuying Liu
Chinese Science Bulletin , 1997, DOI: 10.1007/BF02882646
Abstract:
Dimerization reaction of C60
Dayong Sun,Ziyang Liu,Xinghua Guo,Yuequan Sun,Shuying Liu
Chinese Science Bulletin , 1997, DOI: 10.1007/BF03182633
Abstract:
Production, extraction and characterization of dilutetium fullerenes
Chunyan Hao,Xinghua Guo,Ziyang Liu,Shuying Liu
Chinese Science Bulletin , 1997, DOI: 10.1007/BF02882542
Abstract:
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