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Search Results: 1 - 10 of 44516 matches for " Ren Hai-Peng "
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A Novel Carrier Waveform Inter-Displacement Modulation Method in Underwater Communication Channel
Hai-Peng Ren,Yang Zhao
Computer Science , 2013,
Abstract: As the main way of underwater wireless communication, underwater acoustic communication is one of the focuses of ocean research. Compared with the free space wireless communication channel, the underwater acoustic channel suffers from more severe multipath effect, the less available bandwidth and the even complex noise. The underwater acoustic channel is one of the most complicated wireless communication channels. To achieve a reliable underwater acoustic communication, Phase Shift Keying (PSK) modulation and Passive Time Reversal Mirror (PTRM) equalization are considered to be a suitable scheme. However, due to the serious distortion of the received signal caused by the channel, this scheme suffers from a high Bit Error Rate (BER) under the condition of the low Signal to Noise Ratio (SNR). To solve this problem, we proposes a Carrier Waveform Inter-Displacement (CWID) modulation method based on the Linear Frequency Modulation (LFM) PSK and PTRM scheme. The new communication scheme reduces BER by increasing the difference from the carrier waveform for different symbols. Simulation results show the effectiveness and superiority of the proposed method.
Inverse-system control of chaos using fuzzy-neural network

Ren Hai-Peng,Liu Ding,

物理学报 , 2002,
Abstract: The Sugeno fuzzy-neural network is employed to establish the inverse system model of chaotic system, and the inverse system method is used to control chaos. The characteristic of this method is to learn the dynamics of a chaotic system and control chaos effectively with the knowledge obtained instead of establishing an analytical model of the chaotic system; moreover, this method does not require the control object to be a stationary point or periodic trajectory. Theoretical analysis and simulations with the Logistic and Henon models prove that this method is effective.
Chaos control based on least square support vector machines

Liu Han,Liu Ding,Ren Hai-Peng,
刘 涵
,刘 丁,任海鹏

物理学报 , 2005,
Abstract: A new chaos control method based on Least-Square Support Vector Machines (LS-SVM) is proposed which has the excellent nonlinearity approximation ability and b etter generalization capability. Many chaotic systems can be composed into a sum of a linear and a nonlinear parts. LS-SVM has been applied in off-line identification of nonlinear part in continuous chaos system, and the identification mode l has been joined in system to compensate nonlinearity. Subsequently a linear st ate feedback controller has been developed to drive chaotic system to desirable points. It is proven by simulations for three representative continuous chaotic systems that the proposed method is effective to control the chaotic system and closed-loop system with state feedback, and the LS-SVM approximator is stable.
Strip Steel Surface Defect Recognition Based on Complex Network Characteristics

REN Hai-Peng,MA Zhan-Feng,

自动化学报 , 2011,
Abstract: A feature extraction method based on the characteristics of dynamic evolution complex networks is proposed for the strip steel surface defect recognition. The extracted features possess displacement, rotation and size invariability, strong anti-interference ability and robustness, therefore they are good classification features for steel surface defect recognition. In order to improve the efficiency of classification, the principal component analysis (PCA) is adopted to reduce the dimension of the feature vector. The directed acyclic graph support vector machine (DAG-SVM) algorithm is used for the defect classification. The experimental results show that this method is of high recognition rate and fast recognition speed.
Bifurcation behaviours of peak current controlled PFC boost converter

Ren Hai-Peng,Liu Ding,
,刘 丁

中国物理 B , 2005,
Abstract: Bifurcation behaviours of the peak current controlled power-factor-correction (PFC) boost converter, including fast-scale instability and low-frequency bifurcation, are investigated in this paper. Conventionally, the PFC converter is analysed in continuous conduction mode (CCM). This prevents us from recognizing the overall dynamics of the converter. It has been pointed out that the discontinuous conduction mode (DCM) can occur in the PFC boost converter, especially in the light load condition. Therefore, the DCM model is employed to analyse the PFC converter to cover the possible DCM operation. By this way, the low-frequency bifurcation diagram is derived, which makes the route from period-double bifurcation to chaos clear. The bifurcation diagrams versus the load resistance and the output capacitance also indicate the stable operation boundary of the converter, which is useful for converter design.
Hopf bifurcation analysis of Chen circuit with direct time delay feedback

Ren Hai-Peng,Li Wen-Chao,Liu Ding,

中国物理 B , 2010,
Abstract: Direct time delay feedback can make non-chaotic Chen circuit chaotic. The chaotic Chen circuit with direct time delay feedback possesses rich and complex dynamical behaviours. To reach a deep and clear understanding of the dynamics of such circuits described by delay differential equations, Hopf bifurcation in the circuit is analysed using the Hopf bifurcation theory and the central manifold theorem in this paper. Bifurcation points and bifurcation directions are derived in detail, which prove to be consistent with the previous bifurcation diagram. Numerical simulations and experimental results are given to verify the theoretical analysis. Hopf bifurcation analysis can explain and predict the periodical orbit (oscillation) in Chen circuit with direct time delay feedback. Bifurcation boundaries are derived using the Hopf bifurcation analysis, which will be helpful for determining the parameters in the stabilisation of the originally chaotic circuit.
Breaking chaotic shift key communication via adaptive key identification

Ren Hai-Peng,Han Chong-Zhao,Liu Ding,

中国物理 B , 2008,
Abstract: This paper proposes an adaptive parameter identification method for breaking chaotic shift key communication from the transmitted signal in public channel. The sensitive dependence property of chaos on parameter mismatch is used for chaos adaptive synchronization and parameter identification. An index function about the synchronization error is defined and conjugate gradient method is used to minimize the index function and to search the transmitter's parameter (key). By using proposed method, secure key is recovered from transmitted signal generated by low dimensional chaos and hyper chaos switching communication. Multi-parameters can also be identified from the transmitted signal with noise.
Identification and chaotifying control of a class of system without mathematical model

REN Hai-peng,LIU Ding,
,刘 丁

控制理论与应用 , 2003,
Abstract: Fuzzy neural network (FNN) was proposed to identify the dynamics of a class of non-chaotic system without mathematical model. The result of identification was then used in inverse system method, by which chaotifying control of the system could be implemented. This method was independent of the exact mathematic model of the system to be controlled. It was testified that error of control caused by the identification error was less than the identification error by properly designed control parameters. Simulation results for continuous and discrete systems show the effectiveness of the method.
Tracking control of chaos in the rolling process of a 6-high UC mill

REN Hai-peng,LIU Ding,
,刘 丁

控制理论与应用 , 2002,
Abstract: The tracking control based on exact feedback linearization is proposed to control chaos existing in the rolling process of 6-high UC mill. This approach can control the industrial chaos at arbitrary point or track function input according to requirements of industrial process or technics, and its effectiveness is not subject to noise and model error. Simulation result proves that the approach is effective and feasible.
Partial decoupling control of chaos in permanent magnet synchronous motor

LI Jie,REN Hai-peng,
李 洁

控制理论与应用 , 2005,
Abstract: Permanent magnet synchronous motor(PMSM) demonstrates chaotic phenomena when its parameters are in a certain range of values.Chaos degrades the performance of the motor drive systems;therefore it should be eliminated.The existing methods for chaos control in motor drive systems,whose control objective is limited to periodic orbits or equilibrium points,can not meet the practical requirement.To solve the problem,the partial decoupling control method based on nonlinear feedback is suggested to control the chaos in PMSM.The direct-axis and quadrature-axis stator voltages are used as the manipulated variables,by which the coupling terms in the direct-axis and quadrature-axis stator current equations are decoupled through the nonlinear feedback of the motor's states.As a direct result of the control force,the controlled system has a unique stable equilibrium point,which can be set to any value according to the practical requirement.At any time,once the partial decoupling control is used for the chaotic PMSM,the chaotic motion in PMSM will be stabilized at a predetermined equilibrium point.In this way,the chaos is eliminated in PMSM.The relationship between controlled system responses and control parameters is investigated,which gives guidance for parameter selection.The simulation results show that the theoretical analysis is correct and the method is effective.
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