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1.
为了更好地分析限价指令簿(LOBs)的趋势,文中提出面向LOBs趋势分析的网络集成模型(NEM-LOB).模型融合2个长短期记忆(LSTM)子模型和1个卷积神经网络(CNN)子模型.一个LSTM子模型可通过LOBs的分布信息捕捉全局时间依赖性,另一个LSTM子模型可通过LOBs和订单流的动态信息捕捉全局动态性.CNN子模型通过LOBs的事实信息提取局部特征.最后,结合3个子模型,提取特征以获得预测结果.在FI-2010数据集上的实验表明NEM-LOB通过引入订单流信息,能对LOBs进行更好的趋势分析.  相似文献   
2.
针对整数阶滑模控制在无刷直流电机系统中容易引起的抖振现象,以及无刷直流电机系统的非线性、实时性,设计一种模糊分数阶滑模控制器。在整数阶滑模控制器的基础上,在滑模切换函数中加入分数阶微积分算子,结合系统二阶状态方程和指数趋近律,设计了分数阶滑模控制器,并且通过Lyapunov稳定性原理和分数阶微积分理论证明了系统的稳定性。仿真及试验的结果表明,对比传统的整数阶滑模控制,所提方法可以有效减弱无刷直流电机系统的抖振,具有更好的动静态控制性能。  相似文献   
3.
In this paper, a novel interval type-2 fuzzy fractional order super twisting algorithm (IT2FFOSTA) which is essentially a second order sliding mode controller is presented. The proposed IT2FFOSTA enhances fractional order super twisting algorithm (FOSTA) by taking advantage of an interval type-2 fuzzy fractional order sliding surface (IT2FFOSS) for some classes of fully-actuated and under-actuated nonlinear systems in presence of uncertainty. The FOSTA significantly reduces the amount of chattering and the IT2FFOSS results in decreasing the tracking error, control effort, and chattering level. In order to control under-actuated systems, a hierarchical sliding surface is employed. The multi-tracker optimization algorithm is utilized to adjust the controller’s parameters; this leads to an optimal performance for the IT2FFOSTA. To examine the performance of the IT2FFOSTA, some simulation and experimental tests on three examples of different classes of fully-actuated and under-actuated systems, including ball and plate, inverted pendulum, and ball and beam systems are carried out. The simulation and experimental results demonstrate the superiority of the IT2FFOSTA in reducing the amount of chattering, tracking error, and control effort compared to those of the other control methods.  相似文献   
4.
The present paper deals with global existence of weak solutions of a time-space fractional Landau–Lifshitz–Bloch equation involving the weak Caputo derivative and a fractional Laplacian. We use Faedo–Galerkin method with some commutator estimates in order to prove global existence of weak solutions for the model. The uniqueness is also discussed in a special one dimensional case.  相似文献   
5.
A numerical method to achieve the simultaneous computation of the seepage flows in porous media and the Navier-Stokes flows in the domain occupied purely by a fluid is presented in this paper. The method uses the Darcy-Brinkman equations with the continuous modelling of the interfacial flow velocity, and applies the finite volume method to the spatial discretization and the fractional step method to the numerical simulation of the incompressible fluid. The coupling of the two different flows is realized by the relevant interpolation of the pressure and the flow velocity onto the interface at which permeability and porosity are discontinuous. The interpolation schemes provide simple solutions to overcome the computational instability caused by the discontinuous change in permeability and to avoid having to resolve the considerably thin transition zone near the interface. Numerical analyses of the one-dimensional uniform flow, the lid-driven cavity flow, and the pipe-flow in a porous medium have been carried out. The results have shown that the proposed schemes enable a stable computation and fulfill the accurate and physically realistic numerical solutions.  相似文献   
6.
In this article is about off grid medium scale Proton Exchange Membrane (PEM) Fuel Cell (FC) Renewable Energy System (FCRES). It is aimed to investigate the elimination of reactive power on the loads fed from the FCRES by using PI-Model Predictive Control (PI-MPC), Fractional PI (PIλ)-Model Predictive Control (PIλ−MPC) and Two-Degree of Freedom PI (2DOFPI)-Model Predictive Controller (2DOFPI-MPC). The effectiveness of these controllers were examined and compared both when controlling reactive power and using different control techniques. The reactive power was attempted to be eliminated using Static Synchronous Compensator (STATCOM). An advanced controller structure has been introduced by controlling capacitor voltages by switching 24 IGBTs in the 5-level inverter within its structure. In this way, the efficiency of the system was increased. The system was simulated in MATLAB/Simulink environment. System consisted of FC, STATCOM, loads, filter, coupling inductance, measurement units and advanced hybrid controllers. In the study, system behavior was also examined in the case of compensation in the system consisting of FCs working off grid.  相似文献   
7.
Molten plastics are characterised with high viscosity and low thermal conductivity. Applying falling film pyrolysis reactor to deal with waste plastics can not only improve heat transfer efficiency, but also solve the flow problem.In this work, the pyrolysis process of molten polypropylene(PP) in a vertical falling film reactor is experimentally studied, and the influence of heating temperature on pyrolysis products is discussed. It has been found that with the temperature increases from 550 ℃ to 625 ℃, the yield of pyrolysis oil decreases from 74.4 wt%(± 2.2 wt%) to53.5 wt%(±1.3 wt%). The major compositions of the pyrolysis oil are C_9, C_(12) and C_(18), and β-scission reactions are predominant. The content of the light fraction C_6-C_(12) of pyrolysis oil is 69.7 wt%. Compared with other pyrolysis reactors, the yield of oil from vertical falling film pyrolysis reactor is slightly higher than that from tubular reactor,equal to that from rotary kiln reactor, and slightly lower than that in medium fluidised-bed reactor.  相似文献   
8.
In this paper, a new tuning method of variable-order fractional fuzzy PID controller (VOFFLC) is proposed for a class of fractional-order and integer-order control plants. Fuzzy logic control (FLC) could easily deal with parameter variations of control system, but the fractional-order parameters are unable to change through this way and it has confined the effectiveness of FLC. Therefore, an attempt is made in this paper to allow all the five parameters of fractional-order PID controller vary along with the transformation of system structure as the outputs of FLC, and the influence of fractional orders λ and μ on control systems has been investigated to make the fuzzy rules for VOFFLC. Four simulation results of different plants are shown to verify the availability of the proposed control strategy.  相似文献   
9.
成品油管道顺序输送计划调度的制定是长距离石油管道运转中最关键的环节之一,制定能够满足上游和下游的需求且保证管道的使用安全性、高效性的计划调度为在调度管理中首要的使命。成品油管道计划调度包括成品油输送批次顺序、批量大小、管道线路的流量、分输站分输的时间等,是比较复杂的决策过程。首先说明了成品油顺序输送,以及介绍了国内外成品油调度计划的研究历史,然后归纳了国内部分学者主要调度方法及模型求解方法,最后描述了中国成品油管道调度计划发展的方向。  相似文献   
10.
如何高效逼真地动态重现书法作品的创作过程日益成为亟需解决的问题,因此文中提出基于主曲线的书法字动态重现方法,解决当前细化算法在提取骨架时存在的无效分支较多、不能保证笔画的连续性和准确性的问题.结合书法字自身结构对主曲线算法进行改进和优化.对书法图像进行骨架提取、骨架追踪、笔顺获取等处理,结合骨架信息和二值图像实现笔画宽度复原,针对笔画宽度存在的“肿瘤”问题,提出“角点剔除法”进行修正,结合HTML5的Canvas绘图技术进行书法字动态书写过程.在模拟数据集上的实验表明,文中算法的书法动态重现取得较好效果.  相似文献   
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