基于神经网络的PID控制及其仿真

提出基于神经网络的PID控制方案,利用神经网络的自学习能力对PID控制参数在线整定,使PID控制器具有自适应性.这里采用三层前向网络、动态BP算法,达到了在线实时控制的目的,显示了BP神经网络的PID控制方法很强的鲁棒性,同时也显示了神经网络在解决高度非线性和严重不确定系统方面的潜能.最后用Matlab软件对一个实例进行仿真研究.仿真结果表明,神经网络PID控制器优于传统PID控制器,具有较高的精度和较强的适应性,它可以获得满意的控制效果.     

混沌光学系统的前向神经网络系统辨识研究

为解决混沌光学系统自适应控制所需之控制参考动力学模型问题，以布拉格声光混沌系统的系统辨识为例．研究了利用前向神经网络对混沌光学系统进行系统辩识的可行性。计算机仿真实验发现．在静态ＢＰ算法支持下一结构十分简单的三层ＢＰ前向神经网络（１：４：１）即可在一定的精度范围内完成对布拉格声光混沌系统的系统辨识．此结果表明．三层前向ＢＰ神经网络在静态ＢＰ算法的支持下确是一良好的混沌光学系统辨识器，因而可用来处理混沌光学时间序列以进行混沌光学系统的动力学重构。     

基于优化BP神经网络的PID控制研究与仿真

PID控制要取得较好的控制效果．就必须通过调整好比例、积分和微分三种控制作用，形成控制量中既相互配合又相互制约的关系。优化BP神经网络是一种前向神经元网络，具有学习速率快、振荡小、精度高的优点，将其隐含层单元分别作为比例（P）、积分（I）、微分（D）单元。可以建立参数自学习的PID控制器。仿真结果表明基于优化BP神经网络的PID控制器具有较好的自学习和自适应性。     

PID神经网络在飞控解耦中的仿真研究

在进行飞行控制律设计时,为了获得好的控制品质,有必要对各输出量进行解耦,并且使控制器能根据被控对象动力学特性的改变而自适应调整。为此,介绍了两种PID神经网络解耦控制结构和一种神经网络辨识器,并分别给出了PID神经网络解耦控制器和辨识器的前向算法及反向传播算法;最后分别应用两种解耦方法针对飞机横侧向线性模型进行计算仿真,得到了两种解耦结果;证明了PID神经网络解耦控制的有效性,并比较了两种结构的优缺点。     

基于遗传算法的神经网络自适应控制器的研究

提出了一种基于遗传算法的神经网络自适应控制器的设计方法。该控制器主要由2部分组成，第一部分利用遗传算法搜索出一组神经网络控制器的初始权值，第二部分用历史输入输出数据训练神经网络自适应控制器，经过训练后其达到稳定的控制效果。通过Matlab仿真表明，该控制策略克服了BP算法对初始值敏感的问题，有效提高神经网络的控制效果，和常规PID控制器相比较，超调量小、抗干扰性强和鲁棒性好。     

有源电力滤波器新型神经网络控制方法

基于神经网络理论和瞬时无功功率理论，提出了一种新型有源电力滤波器控制方法，消除了电源电流在负载电流发生突变处产生的锯齿抖动。这种方法实时检测负载电流的二阶导数，判断负载电流是否发生突变。发生突变则采用基于神经网络理论的程序模块进行补偿电流控制。神经网络模块采用离线训练方法，应用误差反向传播(BP)算法，选择前向三层人工神经网络的模型得以实现。这种方法可以应用在单相、三相电力系统的滤波电路中。仿真结果证明了这种算法的有效性。     

神经网络在AMT流量控制中的应用

以ＡＴＭＩ流量控制的三层结构模型为基础，介绍神经网络在接入允许控制中的五种算法－学习控制方法，ｈｙｂｒｉｄ允许方法，移动窗口训练方法，ＢＰＨＴ算法和时间－差分学习方法。讨论基于神经网络的流量测量，流量管理和拥塞控制方法。性能分析结果表明神经网络提供了快速，自适应，简单的智能控制。／     

神经网络在ATM流量控制中的应用

以ATM流量控制的三层结构模型为基础，介绍神经网络在接入允许控制（CAC）中的五种算法——学习控制方法、hybrid允许方法、移动窗口训练方法，BPHT算法和时间-差分学习方法。讨论基于神经网络的流量测量、流量管理和拥塞控制方法。性能分析结果表明神经网络提供了快速、自适应、简单的智能控制。     

神经网络在无人机自动飞行控制系统中的应用

采用神经网络与PID控制相结合的方法，提出了一种基于BP神经网络Kp、Kl、KD参数自学习的PID控制器，较好地解决了传统控制方式对于对象模型过于依赖、参数在线整定困难等问题。同时对BP算法进行了深入分析，引入了神经网络的自适应学习速率和带死区控制，进一步提高了算法的收敛性。利用本文所提出的算法对某型无人机进行控制设计仿真实验，仿真结果表明：该算法在跟踪速率、控制精度上明显优于传统的PID控制器，对无人机具有良好的控制效果。     

一种改进的神经网络自适应控制方法

本文提出了一种改进的神经网络的控制方法，该方法引入一个神经网络辨识器同时作了为神经网络控制器的输出层，从而可以直接通过系统的期望输出和实际输出之差来神经网络控制器的权值，更好地适应对象的非线性和变化。     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

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正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its