Weihua Gui

Central South University, Ch’ang-sha-shih, Hunan, China

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Publications (175)75.35 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Iron precipitation by goethite plays an important role in zinc hydrometallurgy. The ferrous ion concentration, which is a key index for assessing the iron removal rate and process control results, cannot be measured on-line. In this study, an integrated predictive model of the ferrous ion concentration is established by integrating the mechanism model and error compensation model, which is based on data identification. The mechanism model is proposed based on an analysis of the process reaction and considering the reaction unit as a continuous stirred tank reactor model. For unknown parameters in the mechanism model, a double-particle swarm optimization algorithm based on information exchange and dynamic adjustment of the feasible region is developed for optimal selection. To improve the adaptive capability of the integrated model, we propose a model-updating strategy and parameter calibration method based on a sensitivity analysis to accomplish on-line adaptive updating of the predictive model. The simulation results demonstrate that the proposed model can effectively track the variation tendency of the ferrous ion concentration and successfully improve the adaptability of the integrated model.
    Hydrometallurgy 11/2014; · 2.17 Impact Factor
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    ABSTRACT: This paper studies the analysis of parametric stability and decentralized state feedback control of a kind of quantized interconnected systems. The output of each controller is quantized logarithmically before it is input to the subsystem, and the quantized density would affect the stability of the systems. First, a decentralized state feedback controller is designed for interconnected systems without quantization and the corresponding stable region is obtained. Second, for a given controller, the lower bound of the quantization density is evaluated from parameters of local controllers. Finally, the proposed method is applied to coupled inverted pendulums systems which can be viewed as quantized interconnected systems. The simulation results show that by using the proposed quantized controllers, the interconnected inverted pendulum systems are parametrically stabilized.
    Asian Journal of Control 09/2014; · 1.41 Impact Factor
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    ABSTRACT: In the context of liberalized markets, market outcomes generally result from the strategic interactions of all market players. Generation company (Genco), as the distributed players, build their subjective demand evaluations (SDFs) about market for optimal bidding purpose. Due to the differences in terms of data availability and modeling techniques, subjective demand models held by various Gencos are heterogeneous and normally deviate from the real market model as well. The picture of a real electricity market game in Genco’s eye is ‘playing is believing’. Therefore, a question naturally comes to the table: how those SDFs with the heterogeneous manner impact individual player’s decision and game results. To answer this question, this paper relaxes a conventional assumption, commonly used in the classical oligopolistic equilibrium model, that one correct and uniform demand knowledge is shared by all Gencos. The results suggest that the system equilibriums would be influenced by the Gencos’ knowledge about market demand. The economic value of demand information is assessed regarding the system performances.
    International Journal of Electrical Power & Energy Systems 09/2014; 60:182–189. · 3.43 Impact Factor
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    ABSTRACT: In this study, the guaranteed cost control of discrete time uncertain system with both state and input delays is considered. Sufficient conditions for the existence of a memoryless state feedback guaranteed cost control law are given in the bilinear matrix inequality form, which needs much less auxiliary matrix variables and storage space. Furthermore, the design of guaranteed cost controller is reformulated as an optimization problem with a linear objective function, bilinear, and linear matrix inequalities constraints. A nonlinear semi-definite optimization solver—PENLAB is used as a solution technique. A numerical example is given to demonstrate the effectiveness of the proposed method. Copyright © 2014 John Wiley & Sons, Ltd.
    Optimal Control Applications and Methods 08/2014; · 1.06 Impact Factor
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    ABSTRACT: As an effective measurement indicator of bubble stability, bubble size structure is believed to be closely related to flotation performance in copper roughing flotation. Moreover, reagent dosage has a very important influence on bubble size structure. In this paper, a novel reagent dosage predictive control method based on probability density function (PDF) of bubble size is proposed to implement the indices of roughing circuit. Firstly, the froth images captured in the copper roughing are segmented by using a two-pass watershed algorithm. In order to characterize bubble size structure with non-Gaussian feature, an entropy based B-spline estimator is hence investigated to depict the PDF of the bubble size. Since the weights of B-spline are interrelated and related to the reagent dosage, a multi-output least square support vector machine (MLS-SVM) is applied to depict a dynamic relationship between the weights and the reagent dosage. Finally, an entropy based optimization algorithm is proposed to determine reagent dosage in order to implement tracking control for the PDF of the output bubble size. Experimental results can show the effectiveness of the proposed method.
    Control Engineering Practice 08/2014; 29:1–12. · 1.67 Impact Factor
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    ABSTRACT: As an effective measurement of bubble stability, bubble size structure is believed to be closely related to flotation performance. Reagent dosage has a very important influence on bubble size. A novel probability density function (PDF) of bubble size based reagent dosage control method is proposed in the paper. First, froth images acquired by camera with big and tiny blobs are segmented by use of an improved two-pass watershed algorithm. With non-Gaussian features, the PDF of the bubble size is hence approximated by the estimator based on B-spline such that the PDF of the bubble size is characterized by a weight vector of the B-spline. Finally, a PDF-based reagent dosage control algorithm is proposed to make the output PDF track the given PDF according to the linear matrix inequality technique, which is established to solve its stability condition by Lyapunov stability analysis. Experimental results show the effectiveness of the proposed method.
    Asian Journal of Control 03/2014; · 1.41 Impact Factor
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    ABSTRACT: In this paper, an adaptive fault detection scheme based on a recursive principal component analysis (PCA) is proposed to deal with the problem of false alarm due to normal process changes in real process. Our further study is also dedicated to develop a fault isolation approach based on Generalized Likelihood Ratio (GLR) test and Singular Value Decomposition (SVD) which is one of general techniques of PCA, on which the off-set and scaling fault can be easily isolated with explicit off-set fault direction and scaling fault classification. The identification of off-set and scaling fault is also applied. The complete scheme of PCA-based fault diagnosis procedure is proposed. The proposed scheme is first applied to Imperial Smelting Process, and the results show that the proposed strategies can be able to mitigate false alarms and isolate faults efficiently.
    ISA Transactions 01/2014; · 2.26 Impact Factor
  • Source
    Ning Chen, Yutian Liu, Bo Liu, Weihua Gui
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    ABSTRACT: The paper considers the parametric absolute stabilization for interconnected Lurie time-delay systems with polytopic uncertainty. The concept of parametric absolute stabilization characterizes both the existence and the stability of equilibrium in the case of uncertain parameters and reference input shift. First, the existing conditions of parametric stability and the stable region are studied by the change of the uncertain parameters and reference input based on decentralized state feedback. Then, a delay-dependent absolute stability condition in parametric stabilization region for interconnected Lurie time-delay systems with polytopic uncertainties is obtained through a linear matrix inequality method. Finally, an example is given to illustrate the effectiveness of the proposed method.
    Asian Journal of Control 01/2014; 16(1). · 1.41 Impact Factor
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    ABSTRACT: In zinc hydrometallurgy, an advanced copper removal process purifies zinc sulfate solution through a series of chemical reactions with recycled underflow by using zinc powder in zinc hydrometallurgy. This paper focuses on the kinetic modeling of the competitive-consecutive reaction system in the copper removal process, and proposes an adaptive parameter optimal selection strategy for different industrial conditions. In the system model, copper cementation, one of the removal reactions, is described by a surface controlled pseudo-first-order rate equation; cuprous oxide precipitation, the other removal reaction, is described by a shrinking core model of a noncatalytic fluid–solid reaction. Because there are several kinetic parameters in the system model, parameter estimation plays an essential role. Because of the complexity and variation in the practical removal process, the kinetic parameters are usually sensitive to alterations in the process conditions. This work solves the parameter estimation problem using an optimal selection strategy. In the strategy, the industrial conditions are classified adaptively according to the system model performance, then the kinetic parameters are selected optimally by evolutionary and particle swarm optimization algorithms for different industrial conditions. Three different representative industrial data sets are used to test the effectiveness and flexibility of the proposed modeling and parameter optimal selection approach in various situations. Finally, the kinetic model is applied to the soft measurement of the practical copper removal process with underflow, and the results demonstrate that the model effectively captures the trends of the removal reactions.
    Industrial & Engineering Chemistry Research. 11/2013; 52(48):17074–17086.
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    ABSTRACT: Core set inconsistency always causes confusion regarding how to select the proper core set for data reduction in inconsistent decision tables. In this paper, partitions of knowledge granules are introduced to analyze this inconsistency, and it is concluded that there are only three types of effective partitions: those that focus on exact information, those that focus on exact, partial, and negative information and those that focus on exact, partial, negative, and probabilistic information. All useful core sets are calculated systematically by converting the three types of partitions to corresponding discernibility matrices. Then, we define three types of rules, positive, inexact, and confidence rules, based on the three types of partitions. Using these rules, an intelligible rule-based strategy is proposed to select the proper core set for a practical application, which resolves the confusion caused by core set inconsistency and completes the process of data reduction. Experimental analysis and industrial results demonstrate the effectiveness of the selection strategy.
    Information Sciences. 08/2013; 241:138–147.
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    ABSTRACT: A novel froth image analysis based production condition recognition method is presented to identify the froth phases under various production conditions. Gabor wavelet transformation is employed to froth image processing firstly due to the ability of Gabor functions in simulating the response of the simple cells in the visual cortex. Successively, the statistical distribution profiles based feature parameters of the Gabor filter responses rather than the conventional mean and variance are extracted to delineate the essential statistical information of the froth images. The amplitude and phase representations of the Gabor filter responses are both taken into account by empirical marginal and joint statistical modeling. At last, a simple learning vector quantization (LVQ) neural network model is used to learn an effective classifier to recognize the froth production conditions. The effectiveness of this method is validated by the real production data on industrial scale from a bauxite dressing plant.
    International Journal of Computational Intelligence Systems 06/2013; 6(5):969-986. · 1.47 Impact Factor
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    ABSTRACT: We propose and investigate a new general model of fuzzy complex network systems described by Takagi-Sugeno (T-S) fuzzy model with time-varying delays. Hybrid synchronization problem is discussed for this general T-S fuzzy complex dynamical network with nondelayed and delayed coupling between nodes. Utilizing Lyapunov-Krasovskii functional method, synchronization stability criteria for the networks are established in terms of linear matrix inequalities (LMIs). These criteria reveal the relationship between coupling matrices with time-varying delays and synchronization stability of the dynamical network. Numerical simulation is provided to illustrate the effectiveness and advantage of derived theoretical results.
    Mathematical Problems in Engineering 05/2013; 2013. · 1.38 Impact Factor
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    ABSTRACT: Generalized traveling salesman problem (GTSP) is an extension of classical traveling salesman problem (TSP), which is a combinatorial optimization problem and an NP-hard problem. In this paper, an efficient discrete state transition algorithm (DSTA) for GTSP is proposed, where a new local search operator named \textit{K-circle}, directed by neighborhood information in space, has been introduced to DSTA to shrink search space and strengthen search ability. A novel robust update mechanism, restore in probability and risk in probability (Double R-Probability), is used in our work to escape from local minima. The proposed algorithm is tested on a set of GTSP instances. Compared with other heuristics, experimental results have demonstrated the effectiveness and strong adaptability of DSTA and also show that DSTA has better search ability than its competitors.
    04/2013;
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    ABSTRACT: As an important indicator of flotation performance, froth texture is believed to be related to operational condition in sulphur flotation process. A novel fault detection method based on froth texture unit distribution (TUD) is proposed to recognize the fault condition of sulphur flotation in real time. The froth texture unit number is calculated based on texture spectrum, and the probability density function (PDF) of froth texture unit number is defined as texture unit distribution, which can describe the actual textual feature more accurately than the grey level dependence matrix approach. As the type of the froth TUD is unknown, a nonparametric kernel estimation method based on the fixed kernel basis is proposed, which can overcome the difficulty when comparing different TUDs under various conditions is impossible using the traditional varying kernel basis. Through transforming nonparametric description into dynamic kernel weight vectors, a principle component analysis (PCA) model is established to reduce the dimensionality of the vectors. Then a threshold criterion determined by the TQ statistic based on the PCA model is proposed to realize the performance recognition. The industrial application results show that the accurate performance recognition of froth flotation can be achieved by using the proposed method.
    Mathematical Problems in Engineering 02/2013; 2013. · 1.38 Impact Factor
  • Guisheng Zhai, Ning Chen, Weihua Gui
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    ABSTRACT: The design of quantised dynamic output feedback for decentralised ℋ∞ control systems is considered with multi-input and multi-output. It is assumed that a decentralised dynamic output feedback has been designed for a decentralised continuous-time LTI system, so that the closed-loop system is stable and a desired ℋ∞ disturbance attenuation level is achieved, and that each channel's measurement outputs are quantised before they are passed to the local controller. We propose a local-output-dependent strategy for updating the quantisers' parameters, so that the overall closed-loop system is asymptotically stable and achieves the same ℋ∞ disturbance attenuation level. Both the pre-designed controllers and the quantisers' parameters are constructed in a decentralised manner, depending on local measurement outputs.
    IET Control Theory and Applications 01/2013; 7(10):1408-1414. · 1.72 Impact Factor
  • Yao Sun, Mei Su, Xing Li, Hui Wang, Weihua Gui
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    ABSTRACT: The stability of a matrix converter is investigated in both motor mode and generator mode. Inspired by the impedance ratio criterion, a general constructive method is proposed to stabilize matrix converter. Based on the analysis, it is possible to change the admittance of matrix converter by modifying the output reference voltage and rectifier modulation vector according to the constructive method. As a result, the instability which is caused by negative impedance could be eliminated. Meanwhile, the stability regions are enlarged. Furthermore, the underlying principles of the constructive method are stated in detail and several instructive examples, which comply with these principles, are demonstrated. The essence of some other existing methods used to improve the stability of matrix converter is unveiled, and the difference and similarity between the existing methods and the proposed ones are also discussed. The correctness and feasibility of the proposed method are verified by simulations, as well as experiments.
    IEEE Transactions on Power Electronics 01/2013; 28(1):418-431. · 5.73 Impact Factor
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    ABSTRACT: This paper investigates the decentralized stabilization of large scale feedforward nonlinear systems via saturated delayed feedback. A class of saturated delayed controllers is first proposed for the single-input feedforward nonlinear systems: an appropriate normal form rather than the homogeneous property of feedforward systems is depended on, and a small parameter contained in the normal form is assigned into the control law. By tuning the small parameter, the control design allows an arbitrarily large input delay. This scheme is then extended to the setting of decentralized feedforward nonlinear systems. The effectiveness of the suggested algorithm is verified by simulations.
    Control and Decision Conference (CCDC), 2013 25th Chinese; 01/2013
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    ABSTRACT: In this paper, the Hammerstein fault prediction modeling based on least squares support vector machines (LS-SVM) is presented for the prediction the key parameters of the imperial smelting furnace (ISF). ISF is a nonlinear, multi-input and multi-output (MIMO) system that is difficult to model by the classical methods. Due to the particularly simple structure of the Hammerstein model and the generalization performance of LS-SVM, a Hammerstein model using LS-SVM is built and applied to the ISF. The simulation research shows this model adapts well to the change of parameters, provides accurate prediction and is with desirable application value.
    Control and Decision Conference (CCDC), 2013 25th Chinese; 01/2013
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    ABSTRACT: Laboratory tests were carried out to study the breakage kinetics of diasporic bauxite and determine its breakage distribution function. Non-first order breakage with different deceleration rates for different size intervals is found, which is most probably caused by the heterogeneity of the ore. Piecewise linearization method is proposed to describe the non-first order breakage according to its characteristics. In the method, grinding time is divided into several intervals and breakage is assumed to be first order in each interval. So, the breakage rates are calculated by taking the product of the last interval as feed and then established as a function of particle size and grinding time. Based on the predetermined breakage rate function, the breakage distribution of the ore is back-calculated from the experimental data using the population balance model (PBM). Finally, the obtained breakage parameters are validated and the simulated data are in good agreement with the experimental data. The obtained breakage distribution and the method for breakage rate description are both significant for modeling the full scale ball milling process of bauxite.
    Chinese Journal of Chemical Engineering. 12/2012; 20(6):1198–1205.
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    Canxun Du, Weihua Gui, Zhikun Hu
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    ABSTRACT: Hydroturbines are the key asset in hydroelectric power stations, and their monitoring and diagnosis play an important role in the asset management and maintenance. Hydraulic pressure fluctuation is inevitable during the operation of hydroturbines. It has nonstationarity during transient processes. The hydraulic pressure fluctuation signal measured in the draft tube of an axial-flow hydroturbine during a start-up transient process is analyzed based on ensemble empirical mode decomposition and Hilbert spectrum. The frequency components and their time evolution with the operating conditions are identified. A dominant low frequency component waxing and waning around a constant smaller than the rated rotating frequency exists throughout the transient process, indicating the possible occurrence of vortex core. Both the amplitude and the frequency are time varying, and are closely related to the operating conditions, especially the guide vane opening and switch, but they are not dominated by the speed. The closure and opening of guide vane and the on-off switching of hydroturbine can result in large amplitude pressure fluctuation, even the pressure surges or impulses in draft tube, which may excite the resonance of some parts and destroy the operating stability. The Hilbert spectrum based on ensemble empirical mode decomposition is suitable to analyze the nonstationary hydraulic pressure fluctuation signals of low frequency.
    09/2012;

Publication Stats

261 Citations
75.35 Total Impact Points

Institutions

  • 2002–2014
    • Central South University
      • School of Information Science and Engineering
      Ch’ang-sha-shih, Hunan, China
  • 2011
    • Nanyang Technological University
      • School of Electrical and Electronic Engineering
      Singapore, Singapore
  • 2010
    • University of Duisburg-Essen
      Essen, North Rhine-Westphalia, Germany
  • 2006
    • CSR Zhuzhou Electric Locomotive Research Institute
      Chu-chou-shih, Hunan, China
  • 1994–2000
    • Central South University of Forestry and Technology
      Ch’ang-sha-shih, Hunan, China