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A framework for dynamic modelling of railway track switches considering the switch blades,actuators and control systems
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作者 Saikat Dutta Tim Harrison +2 位作者 Christopher Ward Roger Dixon Phil Winship 《Railway Engineering Science》 EI 2024年第2期162-176,共15页
The main contribution of this paper is the development and demonstration of a novel methodology that can be followed to develop a simulation twin of a railway track switch system to test the functionality in a digital... The main contribution of this paper is the development and demonstration of a novel methodology that can be followed to develop a simulation twin of a railway track switch system to test the functionality in a digital environment.This is important because,globally,railway track switches are used to allow trains to change routes;they are a key part of all railway networks.However,because track switches are single points of failure and safety-critical,their inability to operate correctly can cause significant delays and concomitant costs.In order to better understand the dynamic behaviour of switches during operation,this paper has developed a full simulation twin of a complete track switch system.The approach fuses finite element for the rail bending and motion,with physics-based models of the electromechanical actuator system and the control system.Hence,it provides researchers and engineers the opportunity to explore and understand the design space around the dynamic operation of new switches and switch machines before they are built.This is useful for looking at the modification or monitoring of existing switches,and it becomes even more important when new switch concepts are being considered and evaluated.The simulation is capable of running in real time or faster meaning designs can be iterated and checked interactively.The paper describes the modelling approach,demonstrates the methodology by developing the system model for a novel“REPOINT”switch system,and evaluates the system level performance against the dynamic performance requirements for the switch.In the context of that case study,it is found that the proposed new actuation system as designed can meet(and exceed)the system performance requirements,and that the fault tolerance built into the actuation ensures continued operation after a single actuator failure. 展开更多
关键词 Railway track switch Mathematical modelling Redundant actuation Finite element analysis
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Model switching method of multi-hierarchical model predictive control system 被引量:1
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作者 刘琳琳 周立芳 《化工学报》 EI CAS CSCD 北大核心 2012年第4期1132-1139,共8页
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Switching mechanism for TiO_2 memristor and quantitative analysis of exponential model parameters 被引量:1
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作者 王小平 陈敏 沈轶 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第8期598-604,共7页
The memristor, as the fourth basic circuit element, has drawn worldwide attention since its physical implementation was released by HP Labs in 2008. However, at the nano-scale, there are many difficulties for memristo... The memristor, as the fourth basic circuit element, has drawn worldwide attention since its physical implementation was released by HP Labs in 2008. However, at the nano-scale, there are many difficulties for memristor physical realization. So a better understanding and analysis of a good model will help us to study the characteristics of a memristor. In this paper, we analyze a possible mechanism for the switching behavior of a memristor with a Pt/TiO2/Pt structure, and explain the changes of electronic barrier at the interface of Pt/TiO2. Then, a quantitative analysis about each parameter in the exponential model of memristor is conducted based on the calculation results. The analysis results are validated by simulation results. The efforts made in this paper will provide researchers with theoretical guidance on choosing appropriate values for(α, β, χ, γ) in this exponential model. 展开更多
关键词 MEMRISTOR switching behavior electronic barrier exponential model
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Adaptive switching control of discrete time nonlinear systems based on multiple models 被引量:1
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作者 RuiKAN 《控制理论与应用(英文版)》 EI 2004年第1期43-50,共8页
We use the approach of “optimal” switching to design the adaptive control because the design among multiple models is intuitively more practically feasible than the traditional adaptive control in improving the perf... We use the approach of “optimal” switching to design the adaptive control because the design among multiple models is intuitively more practically feasible than the traditional adaptive control in improving the performances. We prove that for a typical class of nonlinear systems disturbed by random noise, the multiple model adaptive switching control based on WLS (Weighted Least Squares) or projected-LS (Least Squares) is stable and convergent. 展开更多
关键词 Multiple model switching control Adaptive control WLS LS Projected LS
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Multi-objective nonlinear model predictive control through switching cost functions and its applications to chemical processes 被引量:1
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作者 何德峰 余世明 俞立 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第10期1662-1669,共8页
This paper proposes a switching multi-objective model predictive control(MOMPC) algorithm for constrained nonlinear continuous-time process systems.Different cost functions to be minimized in MPC are switched to satis... This paper proposes a switching multi-objective model predictive control(MOMPC) algorithm for constrained nonlinear continuous-time process systems.Different cost functions to be minimized in MPC are switched to satisfy different performance criteria imposed at different sampling times.In order to ensure recursive feasibility of the switching MOMPC and stability of the resulted closed-loop system,the dual-mode control method is used to design the switching MOMPC controller.In this method,a local control law with some free-parameters is constructed using the control Lyapunov function technique to enlarge the terminal state set of MOMPC.The correction term is computed if the states are out of the terminal set and the free-parameters of the local control law are computed if the states are in the terminal set.The recursive feasibility of the MOMPC and stability of the resulted closed-loop system are established in the presence of constraints and arbitrary switches between cost functions.Finally,implementation of the switching MOMPC controller is demonstrated with a chemical process example for the continuous stirred tank reactor. 展开更多
关键词 Nonlinear system model predictive control Multi-objective control switched control Continuous stirred tank reactor
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Hierarchical Switching Control of Multiple Models Based on Robust Control Theory 被引量:4
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作者 GAO FENG LI Ke-Qiang LIAN Xiao-Min 《自动化学报》 EI CSCD 北大核心 2006年第3期411-416,共6页
A new hierarchical switching control system of multiple models based on robust control theory is designed for some plant with large uncertainties. The model set and controller set are designed by robust control theory... A new hierarchical switching control system of multiple models based on robust control theory is designed for some plant with large uncertainties. The model set and controller set are designed by robust control theory and the characteristics of robust control system are taken into account. A new kind of switching index function by estimating uncertainty is designed. Furthermore, stability of the closed system is analyzed by the small gain theorem in the sense of exponentially weighted L2 norm. And simulation is done on a plant with both parameter uncertainty and un-modeled dynamics. Both theoretical analysis and simulation results show that this new hierarchical switching control system can control the plant with large uncertainties effectively and has good performance of tracking and stability. 展开更多
关键词 多模式控制 开关控制 自动化系统 鲁棒控制
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Model Reference Adaptive Control for Switched Systems with Closed-loop Reference Model Under Arbitrary Switching
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作者 Hao Yang Jing Xie Jun Zhao 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2019年第3期35-42,共8页
This paper explores the model reference adaptive control problem for a class of switched linear systems under arbitrary switching with no need for the measurability of the system state.Based on the state of reference ... This paper explores the model reference adaptive control problem for a class of switched linear systems under arbitrary switching with no need for the measurability of the system state.Based on the state of reference model and the measurable output error, adaptive laws and controllers are designed for switched systems.Each subsystem may have its individual reference model and controller, which increases the design flexibility.The introduction of the closed-loop reference model is to get a better transient performance of the whole switched systems.A numerical example is provided to verify the effectiveness of the main results. 展开更多
关键词 switchED systems model REFERENCE adaptive control common LYAPUNOV function arbitrary switching the CLOSED-LOOP REFERENCE model
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Adaptive switching control of a class of nonlinear systems based on mixed multiple models
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作者 曹奇敏 张艳霞 《Journal of Beijing Institute of Technology》 EI CAS 2012年第4期504-509,共6页
The transient behaviors of traditional adaptive control may be very poor in general. A practically feasible approach to improve the transient performances is the adoption of adaptive switc- hing control. For a typical... The transient behaviors of traditional adaptive control may be very poor in general. A practically feasible approach to improve the transient performances is the adoption of adaptive switc- hing control. For a typical class of nonlinear systems disturbed by random noises, mixed multiple models consisting of adaptive model and fixed models were considered to design the switching con- trol law. Under certain assumptions, the nonlinear system with the switching control law was proved rigorously to be stable and optimal A simulation example was provided to compare the performance of the switching control and the traditional adaptive control. 展开更多
关键词 adaptive control nonlinear systems switching control multiple models mixed models
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Effects of two types of noise and switching on the asymptotic dynamics of an epidemic model
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作者 徐伟 王喜英 刘新芝 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第5期163-170,共8页
This paper mainly investigates dynamics behavior of HIV (human immunodeficiency virus) infectious disease model with switching parameters, and combined bounded noise and Gaussian white noise. This model is different... This paper mainly investigates dynamics behavior of HIV (human immunodeficiency virus) infectious disease model with switching parameters, and combined bounded noise and Gaussian white noise. This model is different from existing HIV models. Based on stochastic Ito lemma and Razumikhin-type approach, some threshold conditions are established to guarantee the disease eradication or persistence. Results show that the smaller amplitude of bounded noise and R0 〈 1 can cause the disease to die out; the disease becomes persistent if R0 〉 1. Moreover, it is found that larger noise intensity suppresses the prevalence of the disease even if R0 〉 1. Some numerical examples are given to verify the obtained results. 展开更多
关键词 stochastic switched HIV model Razumikhin-type approach EXTINCTION PERMANENCE
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A Switching Method for a Model Reference Robust Control with Unknown High Frequency Gain Sign
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作者 YUAN Li-Na LIN Yan 《自动化学报》 EI CSCD 北大核心 2006年第4期618-623,共6页
The problem of controlling a single-input-single-output plant without prior knowledge of high frequency gain sign is addressed by using the model reference robust control approach.A switching method is proposed based ... The problem of controlling a single-input-single-output plant without prior knowledge of high frequency gain sign is addressed by using the model reference robust control approach.A switching method is proposed based on a monitoring function so that after a finite number of swi- tchings the tracking error converges to zero exponentially.Furthermore,it is shown that if some initial states of the closed-loop system are zero,only one switching is needed. 展开更多
关键词 model following high-frequency gain robust control switching control
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Analysis and modeling of resistive switching mechanism oriented to fault tolerance of resistive memory based on memristor
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作者 黄达 吴俊杰 唐玉华 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第3期602-607,共6页
With the progress of the semiconductor industry, resistive memories, especially the memristor, have drawn increasing attention. The resistive memory based on memrsitor has not been commercialized mainly because of dat... With the progress of the semiconductor industry, resistive memories, especially the memristor, have drawn increasing attention. The resistive memory based on memrsitor has not been commercialized mainly because of data error. Currently, there are more studies focused on fault tolerance of resistive memory. This paper studies the resistive switching mechanism which may have time-varying characteristics. Resistive switching mechanism is analyzed and its respective circuit model is established based on the memristor Spice model. 展开更多
关键词 resistive RAM fault tolerance resistive switching mechanism circuit model
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Analysis and modeling of resistive switching mechanisms oriented to resistive random-access memory
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作者 黄达 吴俊杰 唐玉华 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第3期522-527,共6页
With the progress of the semiconductor industry,the resistive random-access memory(RAM) has drawn increasing attention.The discovery of the memristor has brought much attention to this study.Research has focused on ... With the progress of the semiconductor industry,the resistive random-access memory(RAM) has drawn increasing attention.The discovery of the memristor has brought much attention to this study.Research has focused on the resistive switching characteristics of different materials and the analysis of resistive switching mechanisms.We discuss the resistive switching mechanisms of different materials in this paper and analyze the differences of those mechanisms from the view point of circuitry to establish their respective circuit models.Finally,simulations are presented.We give the prospect of using different materials in resistive RAM on account of their resistive switching mechanisms,which are applied to explain their resistive switchings. 展开更多
关键词 resistive random-access memory resistive switching mechanism circuit model
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Modeling of Canonical Switching Cell Converter Using Genetic Algorithm
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作者 T.V.Viknesh V.Manikandan 《Computer Modeling in Engineering & Sciences》 SCIE EI 2017年第1期109-116,共8页
The working of Canonical switching cell(CSC)converter was studied and its equivalent circuit during ON and OFF states were obtained.State space model of CSC converter in ON and OFF states were developed using the Kirc... The working of Canonical switching cell(CSC)converter was studied and its equivalent circuit during ON and OFF states were obtained.State space model of CSC converter in ON and OFF states were developed using the Kirchhoff laws.The state space matrices were used to construct the transfer functions of ON&OFF states.The step response of the converter was simulated using MATLAB.The step response curve was obtained using different values of circuit components(L,C1,C2 and RL)and optimized.The characteristic parameters such as rise time,overshoot,settling time,steady state error and stability were determined using the step response curve.The response curve shows that there is no overshoot;the rise time and settling time are very low as expected for a converter and its stability is very high but the amplitude is very.The circuit was tuned to attain the expected amplitude using PID controller with the help of Genetic algorithm.The excellent results of circuits’characteristic parameters are very useful guideline for constructing such CSC converters for DC-DC conversions.The circuit characteristic parameters are useful in constructing such CSC converters for DCDC conversions in driving solar energy using solar panel. 展开更多
关键词 CANONICAL switching CELL CONVERTER STATE-SPACE methods DC-DC CONVERTER step response stability power system modeling switching circuits genetic algorithm PID
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基于Markov-switching GARCH模型的上证50ETF期权定价分析
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作者 闫海波 彭凤娇 《甘肃科学学报》 2023年第1期129-138,共10页
上证50ETF由于其组合资产的对冲,其资产面临的主要是系统风险,通过马尔可夫结构转换GARCH模型(MS-GARCH模型)准确预判上证50ETF波动状态后对其实施风险管理。首先,根据MS-GARCH模型稳态分类方法对上证50ETF波动率划分3个波动区间;其次,... 上证50ETF由于其组合资产的对冲,其资产面临的主要是系统风险,通过马尔可夫结构转换GARCH模型(MS-GARCH模型)准确预判上证50ETF波动状态后对其实施风险管理。首先,根据MS-GARCH模型稳态分类方法对上证50ETF波动率划分3个波动区间;其次,将波动率以滚动窗口形式带入Black-Scholes期权定价模型;最后,运用均方误差、对称平均绝对百分比误差等确定最优模型。实证结果表明:拟合和预测期权价格得到MS-GARCH模型优于GARCH模型。通过准确预判上证50ETF波动状态,在高波动状态情行下可以对上证50ETF提前做好风险管理措施,为金融组合资产系统风险管理提供一个很好的参考依据。 展开更多
关键词 GARCH模型 马尔可夫结构转换GARCH模型 上证50ETF BLACK-SCHOLES期权定价模型
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The Modified Multiple Model Switching Tuning Control Application in AVC
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作者 周烁 李运堂 +1 位作者 孟光 丁汉 《Journal of Shanghai Jiaotong university(Science)》 EI 2007年第1期131-137,共7页
In the complex mechanical vibration environment, the dominant frequency of the system varies remarkably and swiftly under various running conditions, which also characterizes uncertainty and time-variation. It is very... In the complex mechanical vibration environment, the dominant frequency of the system varies remarkably and swiftly under various running conditions, which also characterizes uncertainty and time-variation. It is very impending and important to suppress or isolate the detrimental vibrations related to the above memtoned system with active vibration control (AVC) technology. This paper presented the improved linear quadratic gaussian (LQG) control scheme with a specified filter to realize broadband disturbance/noise attenuation and assure intensive suppression of vibration at the key vibration frequency, then applies and modifies the multiple model switching tuning (MMST) control method by disturbance observation to track the variation of dominant vibration component timely. The effectiveness and superiority of the presented control method were demonstrated by numerical simulation and AVC experiment on a flexible cantilever beam under sweeping excitation. 展开更多
关键词 multiple model switching active vibration control (AVC) disturbance observer
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Markov-Switching Time-Varying Copula Modeling of Dependence Structure between Oil and GCC Stock Markets 被引量:1
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作者 Heni Boubaker Nadia Sghaier 《Open Journal of Statistics》 2016年第4期565-589,共25页
This paper proposes a Markov-switching copula model to examine the presence of regime change in the time-varying dependence structure between oil price changes and stock market returns in six GCC countries. The margin... This paper proposes a Markov-switching copula model to examine the presence of regime change in the time-varying dependence structure between oil price changes and stock market returns in six GCC countries. The marginal distributions are assumed to follow a long-memory model while the copula parameters are supposed to evolve according to the Markov-switching process. Furthermore, we estimate the Value-at-Risk (VaR) based on the proposed approach. The empirical results provide evidence of three regime changes, representing precrisis, financial crisis and post-crisis, in the dependence structure between energy and GCC stock markets. In particular, in the pre- and post-crisis regimes, there is no dependence, while in the crisis regime, there is significant tail dependence. For OPEC countries, we find lower tail dependence whereas in non-OPEC countries, we see upper tail dependence. VaR experiments show that the Markov-switching time- varying copula model performs better than the time-varying copula model. 展开更多
关键词 Time-Varying Copulas Markov-switching model Oil Price Changes GCC Stock Markets VAR
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Dynamic Hedging Based on Markov Regime-Switching Dynamic Correlation Multivariate Stochastic Volatility Model
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作者 王宜峰 《Journal of Donghua University(English Edition)》 EI CAS 2017年第3期475-478,共4页
It is important to consider the changing states in hedging.The Markov regime-switching dynamic correlation multivariate stochastic volatility( MRS-DC-MSV) model was proposed to solve this issue. DC-MSV model and MRS-D... It is important to consider the changing states in hedging.The Markov regime-switching dynamic correlation multivariate stochastic volatility( MRS-DC-MSV) model was proposed to solve this issue. DC-MSV model and MRS-DC-MSV model were used to calculate the time-varying hedging ratios and compare the hedging performance. The Markov chain Monte Carlo( MCMC) method was used to estimate the parameters. The results showed that,there were obviously two economic states in Chinese financial market. Two models all did well in hedging,but the performance of MRS-DCMSV model was better. It could reduce risk by nearly 90%. Thus,in the hedging period,changing states is a factor that cannot be neglected. 展开更多
关键词 volatility return Correlation multivariate neglected deviation stochastic switching stock Gibbs
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我国股指期货的推出对股票现货市场波动的影响研究--基于Markov-Switching-GARCH模型 被引量:12
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作者 华仁海 张朋 《南方经济》 CSSCI 2012年第10期115-122,共8页
为研究我国沪深300股指期货推出对股票现货市场波动性的影响,本文采用Markov-switching-GARCH模型进行了实证分析。之前的文章主要通过引入虚拟变量的方法研究股指期货推出对股票现货市场波动性的影响,由于它是采用外生变量刻画波动变化... 为研究我国沪深300股指期货推出对股票现货市场波动性的影响,本文采用Markov-switching-GARCH模型进行了实证分析。之前的文章主要通过引入虚拟变量的方法研究股指期货推出对股票现货市场波动性的影响,由于它是采用外生变量刻画波动变化的,因此不能反映波动的结构变化,而Markov-sw itching-GARCH模型采用Markov状态转换的GARCH模型,通过内生的方式识别不同的波动状态,这克服了现有研究中的不足。研究结果表明:Markov-switching-GARCH模型能够较好地刻画收益波动的结构变化;沪深300股指期货的引入并没有加剧现货市场波动,相反减缓了现货市场的波动,提高了股票现货市场的稳定性。 展开更多
关键词 股指期货 股票现货 波动性 Markov-switching-GARCH模型
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Nonlinear Auto-Companding Method for Behavioral Modeling of Switched-Current Circuits
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作者 王伟 曾璇 +2 位作者 陶俊 苏仰峰 唐璞山 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第12期1254-1261,共8页
A wavelet collocation method with nonlinear auto companding is proposed for behavioral modeling of switched current circuits.The companding function is automatically constructed according to the initial error distri... A wavelet collocation method with nonlinear auto companding is proposed for behavioral modeling of switched current circuits.The companding function is automatically constructed according to the initial error distribution obtained through approximating the input output function of the SI circuit by conventional wavelet collocation method.In practical applications,the proposed method is a general purpose approach,by which both the small signal effect and the large signal effect are modeled in a unified formulation to ease the process of modeling and simulation.Compared with the published modeling approaches,the proposed nonlinear auto companding method works more efficiently not only in controlling the error distribution but also in reducing the modeling errors.To demonstrate the promising features of the proposed method,several SI circuits are employed as examples to be modeled and simulated. 展开更多
关键词 wavelet collocation method behavioral modeling switched current circuits nonlinear auto companding
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基于Markov-switching-GARCH模型的股指期货与现货市场的相关性影响分析 被引量:5
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作者 陈静思 叶德磊 顾京 《云南财经大学学报》 CSSCI 北大核心 2014年第6期95-101,共7页
通过能识别和捕捉内生性波动状态的Markov-switching-GARCH模型来改进含有虚拟变量的GARCH模型中不能很好地刻画外生性结构变化的不足,选取沪深300股指期货作为参照对现货市场的波动性影响进行分析。实证研究显示:该模型能够较好地刻画... 通过能识别和捕捉内生性波动状态的Markov-switching-GARCH模型来改进含有虚拟变量的GARCH模型中不能很好地刻画外生性结构变化的不足,选取沪深300股指期货作为参照对现货市场的波动性影响进行分析。实证研究显示:该模型能够较好地刻画现货市场收益率的结构变化,反映了股指期货的推出不仅没有加剧现货市场的波动,反而减弱了现货市场的波动程度,使得市场流入的有效信息得到增强,市场运行效率整体得到明显提升。 展开更多
关键词 股指期货 波动性 Markov-switching-GARCH模型 影响
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