Free vibration and critical speed of moderately thick rotating laminated composite conical shell using generalized differential quadrature method

The generalized differential quadrature method （GDQM） is employed to con- sider the free vibration and critical speed of moderately thick rotating laminated compos- ite conical shells with different boundary conditions developed from the first-order shear deformation theory （FSDT）. The equations of motion are obtained applying Hamilton＇s concept, which contain the influence of the centrifugal force, the Coriolis acceleration, and the preliminary hoop stress. In addition, the axial load is applied to the conical shell as a ratio of the global critical buckling load. The governing partial differential equations are given in the expressions of five components of displacement related to the points ly- ing on the reference surface of the shell. Afterward, the governing differential equations are converted into a group of algebraic equations by using the GDQM. The outcomes are achieved considering the effects of stacking sequences, thickness of the shell, rotating velocities, half-vertex cone angle, and boundary conditions. Furthermore, the outcomes indicate that the rate of the convergence of frequencies is swift, and the numerical tech- nique is superior stable. Three comparisons between the selected outcomes and those of other research are accomplished, and excellent agreement is achieved.

Hybrid tri-memristor hyperchaotic map and application in Wasserstein Generative Adversarial Nets

Inspired by basic circuit connection methods,memristors can also be utilized in the construction of complex discrete chaotic systems.To investigate the dynamical effects of hybrid memristors,we propose two hybrid tri-memristor hyperchaotic(HTMH)mapping structures based on the hybrid parallel/cascade and cascade/parallel operations,respectively.Taking the HTMH mapping structure with hybrid parallel/cascade operation as an example,this map possesses a spatial invariant set whose stability is closely related to the initial states of the memristors.Dynamics distributions and bifurcation behaviours dependent on the control parameters are explored with numerical tools.Specifically,the memristor initial offset-boosting mechanism is theoretically demonstrated,and memristor initial offset-boosting behaviours are numerically verified.The results clarify that the HTMH map can exhibit hyperchaotic behaviours and extreme multistability with homogeneous coexisting infinite attractors.In addition,an FPGA hardware platform is fabricated to implement the HTMH map and generate pseudorandom numbers(PRNs)with high randomness.Notably,the generated PRNs can be applied in Wasserstein generative adversarial nets(WGANs)to enhance training stability and generation capability.

A high-speed true random number generator based on Ag/SiNx/n-Si memristor

The intrinsic variability of memristor switching behavior can be used as a natural source of randomness,this variability is valuable for safe applications in hardware,such as the true random number generator(TRNG).However,the speed of TRNG is still be further improved.Here,we propose a reliable Ag/SiNx/n-Si volatile memristor,which exhibits a typical threshold switching device with stable repeat ability and fast switching speed.This volatile-memristor-based TRNG is combined with nonlinear feedback shift register(NFSR)to form a new type of high-speed dual output TRNG.Interestingly,the bit generation rate reaches a high speed of 112 kb/s.In addition,this new TRNG passed all 15 National Institute of Standards and Technology(NIST)randomness tests without post-processing steps,proving its performance as a hardware security application.This work shows that the SiNx-based volatile memristor can realize TRNG and has great potential in hardware network security.

On first-order theorem proving using generalized odd-superpositions Ⅱ

It is shown that the proof system using odd-superpositions Ⅱ is not complete.The reason leading to this incompleteness is that the use of idempotency rule is neglected.By defining the superpositions of first-order polynomials and zero,the concept of odd-superpositions Ⅱ is extended,and a complete proof system using the extended odd-superpositions Ⅱ is developed.In addition,this proof system is an improvement on remainder method;its completeness demonstrates actually that the remainder method using semantic strategy is still complete.

A novel hyperchaotic map with sine chaotification and discrete memristor

Discrete memristor has become a hotspot since it was proposed recently.However,the design of chaotic maps based on discrete memristor is in its early research stage.In this paper,a memristive seed chaotic map is proposed by combining a quadratic discrete memristor with the sine function.Furthermore,by applying the chaotification method,we obtain a high-dimensional chaotic map.Numerical analysis shows that it can generate hyperchaos.With the increase of cascade times,the generated map has more positive Lyapunov exponents and larger hyperchaotic range.The National Institute of Standards and Technology(NIST)test results show that the chaotic pseudo-random sequence generated by cascading two seed maps has good unpredictability,and it indicates the potential in practical application.

基于忆阻循环神经网络的层次化状态正则变分自编码器

变分自编码器(VAE)作为一个功能强大的文本生成模型受到越来越多的关注。然而,变分自编码器在优化过程中容易出现后验崩溃,即忽略潜在变量,退化为一个自编码器。针对这个问题,该文提出一种新的变分自编码器模型,通过层次化编码和状态正则方法,可以有效缓解后验崩溃,且相较于基线模型具有更优的文本生成质量。在此基础上,基于纳米级忆阻器,将提出的变分自编码器模型与忆阻循环神经网络(RNN)结合,设计一种基于忆阻循环神经网络的硬件实现方案,即层次化变分自编码忆组神经网络(HVAE-MNN),探讨模型的硬件加速。计算机仿真实验和结果分析验证了该文模型的有效性与优越性。

基于广义忆阻器的超混沌系统的研究与电路实现

基于通用忆阻器模型,设计了一个广义忆阻器并将其引入混沌系统,构建了一个新的四阶忆阻超混沌系统,探究了其动力学特性。首先对新型四阶忆阻超混沌系统的相图、耗散性、李雅普诺夫指数、稳定性等特性进行分析,发现其存在无穷多平衡点集,且比原系统有更高的维度、混沌性以及复杂度。通过进一步分析其动力学现象,发现随着参数和初值的变化,其分岔特性和李雅普诺夫指数反映出多吸引子共存等现象。最后通过数值仿真与模拟电路仿真的相图对比,验证忆阻混沌系统电路的可行性。新系统有着更复杂的非线性行为,因此具有更高的研究价值,同时为忆阻混沌电路的实际应用奠定了基础。

基于广义忆阻器的Lü超混沌系统分析及其应用

引入一个双曲正切的广义压控忆阻器到Lü混沌系统中,增加混沌系统的复杂程度,构建了一个新型的四阶超混沌忆阻系统.采用Lyapunov指数、分岔图等非线性系统分析方法对忆阻系统进行理论分析,验证系统的超混沌特性.研究忆阻系统的动力学行为,对系统参数与初始值的改变进行分析,得到随参数变化引起的分岔与瞬态混沌现象和随初始值变化的吸引子共存现象.电路仿真及硬件电路验证了该忆阻超混沌系统的正确性与物理可实现性.将该忆阻超混沌系统应用于彩色图像加密中,具有良好的密钥敏感性和丰富的动力学特性,与加密算法结合后可用于保密通信领域.

“新一代智能硬件技术”研究生课程的教学探索

硕士研究生课程是硕士研究生培养环节中的重要一环。开设“新一代智能硬件技术”课程可以使学生理解人工智能领域的相关知识,领悟学科交叉的科研思路,培养学生知识融合与学科交叉的能力。“新一代智能硬件技术”课程介绍了人工智能的发展及相应的理论方法,阐述了研究新一代智能硬件技术的意义,聚焦新兴的忆阻电路设计领域,阐明新一代的忆阻存算一体硬件架构,以及忆阻人工神经网络、忆阻类脑神经网络的实现。“新一代智能硬件技术”课程通过使用案例式教学、科研反哺教学的方式,将课程内容趣味性地、有条理地讲授给学生。同时,采用翻转课堂的方式检验学习效果。

基于有源广义忆阻的无感混沌电路研究

采用常见元器件等效实现一个广义忆阻器,进而制作出一个电路特性可靠的非线性电路,有助于忆阻混沌电路的非线性现象的实验展示及其所产生的混沌信号的实际工程应用.基于忆阻二极管桥电路,构建了一种无接地限制的、易物理实现的一阶有源广义忆阻模拟器;由该模拟器并联电容后与RC桥式振荡器线性耦合,实现了一种无电感元件的忆阻混沌电路;建立了无感忆阻混沌电路的动力学模型,开展了相应的耗散性、平衡点、稳定性和动力学行为等分析.结果表明,无感忆阻混沌电路在相空间中存在分布2个不稳定非零鞍焦的耗散区和包含1个不稳定原点鞍点的非耗散区;当元件参数改变时,无感忆阻混沌电路有着共存分岔模式和共存吸引子等非线性行为.研制了实验电路,该电路结构简单、易实际制作,实验测量和数值仿真两者结果一致,验证了理论分析的有效性.

忆阻器多涡卷混沌系统及其滑模控制同步

通过在Yang系统中添加具有忆阻器性质的项及其他非线性项,提出了一种忆阻混沌系统。改变该系统的参数及状态变量的初值可得到单涡卷、双涡卷和三涡卷的混沌吸引子。以三涡卷时的系统为例,分析了其动力学特性,研究了该系统与加入了干扰信号的Chen系统的广义同步。应用滑模控制方法设计了同步控制器及参数自适应律,并基于Lyapunov稳定性理论得出了实现同步的充分条件,最后将所提出的同步方法与没有引入滑模控制的方法进行了比较。结果表明两个系统实现了同步,参数得到了准确的估计,且该方法比没有引入滑模控制的方法同步速度更快,抗干扰能力更强。

四阶忆阻考毕兹混沌振荡器研究

通过在三阶考毕兹混沌振荡器中引入一阶广义忆阻器,提出了一种新颖的四阶忆阻考毕兹混沌振荡器,其中一阶广义忆阻器由二极管桥级联一阶RC滤波器构成。建立了忆阻考毕兹混沌振荡器的动力学模型,研究了它的平衡点和稳定性,结果表明:四阶忆阻考毕兹混沌振荡器具有唯一的不稳定鞍焦。进一步开展了依赖于电路元件参数的动力学特性研究。采用理论分析、数值仿真和实验验证相结合的方法,对电路展现出的混沌吸引子、周期极限环等复杂的非线性现象进行了研究,实验结果与数值仿真结果相一致,较好地验证了理论分析结果。

基于忆阻器的数模混合随机数发生器

数字方法实现的混沌随机数发生器存在有限字长效应,无法保证随机数良好的统计特性.本文构建了一类包含最少模拟器件的新数模混合系统,分析了混合系统的非线性动力学行为.利用现场可编程逻辑门阵列和一阶广义忆阻器实现了复杂混沌映射,克服了有限字长效应,构造了稳定的高速混沌随机数发生器,可以产生100 Gbit/s以上速率的随机数.研究表明,数模混合系统的混沌性对元件参数变化不敏感.混合系统易于集成在图像加密、保密通信和雷达波形设计等应用系统中.

基于分数阶忆阻器的混沌电路分析与设计

提出了一种新型的分数阶忆阻混沌电路。首先,建立了分数阶忆阻器的数学模型,通过数值仿真验证了分数阶广义忆阻器满足忆阻器的基本特性。然后,将分数阶广义忆阻器与蔡氏振荡电路相结合,建立了一种基于分数阶广义忆阻器的混沌电路模型。通过稳定性理论,对分数阶系统的稳定性进行了分析。为了进一步研究电路参数对系统动态行为的影响,利用相位图和分岔图等分析了系统随参数变化的动力学特性。结果表明,分数阶忆阻混沌电路会表现出周期和混沌等不同的动力学行为。最后,设计了分数阶忆阻混沌电路的等效电路模型,并进行电路仿真验证。实验结果与数值仿真结果基本一致,表明分数阶忆阻混沌电路具有一定的实际应用价值。

基于忆阻器的矩形波信号发生器

利用忆阻器独特的电路学性质,设计了一个基于忆阻器的新型矩形波信号发生器。电路中不含有分立的电容元件,输出波形频率和幅值精确可调。用PSPICE进行仿真分析,仿真结果验证了该方案的有效性。

基于双忆阻混沌电路的分析及应用

设计了一个磁控忆阻器仿真器和一个有源荷控忆阻器仿真器,并基于这两种忆阻器设计了一个新的五维混沌电路系统。对系统进行动力学特性分析,包括平衡点集的求解、稳定性、分岔图、Lyapunov指数谱、共存分岔及多稳定性。结果表明,当参数变化时,系统存在单周期、倍周期及混沌态。特别地,当取不同的初值时,系统出现共存混沌吸引子、共存倍周期和共存单周期的现象。通过分析随初值变化的Lyapunov指数谱与分岔图,表明系统具有多稳定性。对混沌电路进行Multisim电路仿真,仿真结果与Matlab数值仿真一致。此外,用实际器件搭建了硬件电路,该电路结构简单、易于制作,实验结果验证了数值仿真与电路仿真的正确性。最后,基于双忆阻混沌硬件电路实现,设计了一个随机信号发生器。该系统具有良好的初值灵敏性,可以与加密算法相结合,应用在信息加密和保密通信领域。

Exact Distributions of Waiting Time Problems of Mixed Frequencies and Runs in Markov Dependent Trials

We study waiting time problems for first-order Markov dependent trials via conditional probability generating functions. Our models involve α frequency cells and β run cells with prescribed quotas and an additional γ slack cells without quotas. For any given and , in our Model I we determine the waiting time until at least frequency cells and at least run cells reach their quotas. For any given τ ≤ α + β, in our Model II we determine the waiting time until τ cells reach their quotas. Computer algorithms are developed to calculate the distributions, expectations and standard deviations of the waiting time random variables of the two models. Numerical results demonstrate the efficiency of the algorithms.

Electrochemical oxidation of polyethylene glycol in electroplating solution using paraffin composite copper hexacyanoferrate modified (PCCHM) anode

Electrochemical oxidation of polyethylene glycol(PEG) in an acidic(pH 0.18 to 0.42) and high ionic strength electroplating solution was investigated. The electroplating solution is a major source of wastewater in the printing wiring board industry. A paraffin composite copper hexacyanoferrate modified(PCCHM) electrode was used as the anode and a bare graphite electrode was used as the cathode. The changes in PEG and total organic carbon(TOC) concentrations during the course of the reaction were monitored. The efficiency of the PCCHM anode was compared with bare graphite anode and it was found that the former showed significant electrocatalytic property for PEG and TOC removal. Chlorides present in the solution were found to contribute significantly in the overall organic removal process. Short chain organic compounds like acetic acid, oxalic acid, formic acid and ethylene glycol formed during electrolysis were identified by HPLC method. Anode surface area and applied current density were found to influence the electro-oxidation process, in which the former was found to be dominating. Investigations of the kinetics for the present electrochemical reaction suggested that the two stage first-order kinetic model provides a much better representation of the overall mechanism of the process if compared to the generalized kinetic model.

基于广义忆阻器的有源带通滤波器仿真与分析

基于一种广义忆阻器,用其替代有源带通滤波器中的某个电阻,构建一种全新的基于广义忆阻器的有源带通滤波器,并对其进行数学建模及数值仿真。该电路有且仅有一个零平衡点,会产生复杂的非线性动力学行为,譬如混沌、周期、倍周期分岔道路、共存分岔模式等现象。

Structural Reliability Assessment by a Modified Spectral Stochastic Meshless Local Petrov-Galerkin Method

This study presents a new tool for solving stochastic boundary-value problems. This tool is created by modify the previous spectral stochastic meshless local Petrov-Galerkin method using the MLPG5 scheme. This modified spectral stochastic meshless local Petrov-Galerkin method is selectively applied to predict the structural failure probability with the uncertainty in the spatial variability of mechanical properties. Except for the MLPG5 scheme, deriving the proposed spectral stochastic meshless local Petrov-Galerkin formulation adopts generalized polynomial chaos expansions of random mechanical properties. Predicting the structural failure probability is based on the first-order reliability method. Further comparing the spectral stochastic finite element-based and meshless local Petrov-Galerkin-based predicted structural failure probabilities indicates that the proposed spectral stochastic meshless local Petrov-Galerkin method predicts the more accurate structural failure probability than the spectral stochastic finite element method does. In addition, generating spectral stochastic meshless local Petrov-Galerkin results are considerably time-saving than generating Monte-Carlo simulation results does. In conclusion, the spectral stochastic meshless local Petrov-Galerkin method serves as a time-saving tool for solving stochastic boundary-value problems sufficiently accurately.