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981.
高职机电类专业国家精品课程建设成就研究 总被引:1,自引:0,他引:1
在高职国家精品课建设的引导下,高职院校将校企合作办学模式、工学结合人才培养模式落实到专业课程的建设和教学过程中,形成了符合高职人才培养要求的基于工作过程的课程模式,建成了一批有助于培养职业能力、道德素养和可持续发展能力的国家精品课程.在教学改革方面取得了突破性成果,有效地提高了教学质量. 相似文献
982.
983.
本文分析了档案资源整合对公共服务能力提升所起的作用,并通过构建基于“公共价值理论”的公共服务能力概念框架选取评价指标。与经典的“公共价值理论”相比,结合数字档案资源的特点,创新性地将“工作人员的素质”、“数字档案资源整合”和“档案管理机构协同”增加到“公共价值理论”的指标体系中,丰富了“公共价值理论”在此领域中的内涵。为了验证评价指标,本文采用面对面访谈和座谈会交流的形式对9个市级、3个省级的相关档案管理机构展开调研活动,从档案管理机构的角度论证了本概念模型中各个评价指标的合理性、实用性和有效性。 相似文献
984.
Active Fe-and Mn-loaded MCM-41(Fe–Mn/MCM-41),which was synthesized via a hydrothermal reaction followed by impregnation,is used in the heterogeneous Fenton reaction to degrade methyl orange(MO) in aqueous solution. The synthesized samples were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,N_2 adsorption–desorption isotherm analysis,Fourier transform infrared spectroscopy,and X-ray photoelectron spectroscopy. Compared with Fe/MCM-41 and Mn/MCM-41,Fe–Mn/MCM-41 showed higher activity for MO degradation and mineralization. Effects of various operating parameters,such as pH,Mn content,and H_2O_2 dosage,on the degradation process were subsequently investigated. Results of experiments on the effect of radical scavengers revealed that the degradation of MO could be attributed to oxidation by HO_·. The synergy of Fe and Mn species in the Fenton oxidation process was also explained. 相似文献
985.
Zidong Wang Dong Wang Bo Shen Fuad E. Alsaadi 《Journal of The Franklin Institute》2018,355(1):406-420
In this paper, the centralized security-guaranteed filtering problem is studied for linear time-invariant stochastic systems with multirate-sensor fusion under deception attacks. The underlying system includes a number of sensor nodes with a centralized filter, where each sensor is allowed to be sampled at different rate. A new measurement output model is proposed to characterize both the multiple rates and the deception attacks. By exploiting the lifting technique, the multi-rate sensor system is cast into a single-rate discrete-time system. With a new concept of security level, the aim of this paper is to design a filter such that the filtering error dynamics achieves the prescribed level of the security under deception attacks. By using the stochastic analysis techniques, sufficient conditions are first derived such that the filtering error system is guaranteed to have the desired security level, and then the filter gain is parameterized by using the semi-definite programme method with certain nonlinear constraints. Finally, a numerical simulation example is provided to demonstrate the feasibility of the proposed filtering scheme. 相似文献
986.
Yueyang Li Hamid Reza Karimi Choon Ki Ahn Yuan Xu Dong Zhao 《Journal of The Franklin Institute》2018,355(7):3330-3353
This work deals with the problem of optimal residual generation for fault detection (FD) in linear discrete time-varying (LDTV) systems subject to uncertain observations. By introducing a generalized fault detection filter (FDF) with four parameter matrices as the residual generator, a novel FDF design scheme is formulated as two bi-objective optimization problems such that the sensitivity of residual to fault is enhanced and the robustness of residual to unknown input is simultaneously strengthened. A generalized operator based optimization approach is proposed to deduce solutions to the corresponding optimization problems in operator forms, where the related H∞/H∞ or FD performance index is maximized. With the aid of the addressed methods, the connections among the derived solutions are explicitly announced. The parameter matrices of the FDF are analytically derived via solving simple matrix equations recursively. It is revealed that our proposed results establish an operator-based framework of optimal residual generation for some kinds of linear discrete-time systems. Illustrative examples are given to show the applicability and effectiveness of the proposed methods. 相似文献
987.
This paper investigates the tracking consensus problem for the second-order leader systems by designing fractional-order observer, where a periodic sampled-based data event-triggered control is employed. In order to track the position information of leader, observers for followers are designed by fractional-order system, where only the relative position information is available. Furthermore, in the process of observers design, a sampled-based event-triggered strategy is proposed so that observers use the event-triggered sampled-data, to reduce the overall load of the network. In our proposed event-triggered strategy, the event detection only works at every sampling time instant which determines whether the sampled-data should be discarded or used. Under this control strategy, the Zeno-behavior is absolutely excluded since the minimum of inter-event times is inherently lower bounded by one sampling period. It is found that the followers can track state of the leader if fractional-order observers are appropriately designed and relevant parameters are properly selected. By using the generalized Nyquist stability criterion, a necessary and sufficient condition for the observer tracking consensus of the second-order leader systems is derived. The results show that the real and imaginary parts of the eigenvalues of the augmented Laplacian matrix, and fractional-order α of observer play a vital role in reaching consensus. 相似文献
988.
Shigen Gao Hairong Dong Bin Ning Hongwei Wang 《Journal of The Franklin Institute》2018,355(13):5452-5474
In this paper, a novel error-driven nonlinear feedback technique is designed for partially constrained errors fuzzy adaptive observer-based dynamic surface control of a class of multiple-input-multiple-output nonlinear systems in the presence of uncertainties and interconnections. There is no requirements that the states are available for the controller design by constructing fuzzy adaptive observer, which can online identify the unmeasurable states using available output information only. By transforming partial tracking errors into new error variables, partially constrained tracking errors can be guaranteed to be confined in pre-specified performance regions. The feature of the error-driven nonlinear feedback technique is that the feedback gain self-adjusts with varying tracking errors, which prevents high-gain chattering with large errors and guarantees disturbance attenuation with small errors. Based on a new non-quadratic Lyapunov function, it is proved that the signals in the resulted closed-loop system are kept bounded. Simulation and comparative results are given to demonstrate the effectiveness of the proposed method. 相似文献
989.
The terminal iterative learning control is designed for nonlinear systems based on neural networks. A terminal output tracking error model is obtained by using a system input and output algebraic function as well as the differential mean value theorem. The radial basis function neural network is utilized to construct the input for the system. The weights are updated by optimizing an objective function and an auxiliary error is introduced to compensate the approximation error from the neural network. Both time-invariant input case and time-varying input case are discussed in the note. Strict convergence analysis of proposed algorithm is proved by the Lyapunov like method. Simulations based on train station control problem and batch reactor are provided to demonstrate the effectiveness of the proposed algorithms. 相似文献
990.
Zhanqiang Zhang Chunxia Dou Dong Yue Bo Zhang Wei Luo 《Journal of The Franklin Institute》2018,355(17):8874-8890
To achieve the frequency restoration (FR) and accurate reactive power sharing (RPS) in islanded microgrids (MGs), an improved P-f droop control is proposed. Firstly, the inverter impedance, whose value is set by the virtual impedance method, is used to minimize the impact of line resistance on powers coupling and RPS. Then, in order to restore the frequency of distributed generations (DGs) to the rated value, the reference is changed for compensating the frequency deviation (FD) caused by loads change. And the fast FR rate is achieved under a large constant k. Besides, in order to eliminate the inaccuracy of RPS caused by voltages difference (VD), the line voltage drop (LVD) is used to compensate the voltage droop characteristics. The use of voltage feedback ensures that the obtained voltage is desired after the LVD compensation. Finally, the simulation in RT-LAB indicates the effectiveness of proposed method in an islanded MG model. 相似文献