共查询到19条相似文献,搜索用时 49 毫秒
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基于Duffing振子的天然气管道泄漏检测方法 总被引:2,自引:0,他引:2
针对天然气管道泄漏因泄漏声波信号信噪比(SNR)过低而难于检测的问题,研究了基于Duffing振子的天然气管道泄漏检测方法。该方法将待检测数据输入Duffing振子系统,以振子系统的状态转化实现非周期信号中周期信号的检测。为了更好地提高Duffing振子的检测性能,在Duffing振子设计阶段,以随机共振的有关理论为基础,通过对系统输出信噪比的优化来实现Duffing振子的参数设计。基于实际天然气管道泄漏数据的测试结果表明,所提出方法可在低信噪比(-68dB)的情况下有效检测出泄漏,具有较好的检测性能。 相似文献
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基于多维Hermite多项式的经典均相混沌展开,考察了Duffing振子随机最优多项式控制的正交展开方法,阐明了多项式系数演化与振子系统反应、最优控制力概率特性之间的联系.系统输入采用Karhunen-Loève展开表现的随机地震动.为降低混求解规模,引入位移-速度范数准则,发展了自适应混沌多项式展开策略.同时,基于Lyapunov稳定条件设计控制器的控制增益参数.数值算例分析表明,受控后系统位移和加速度的均方特征得到改善、振子系统的非线性程度减小,基于混沌多项式展开的最优控制方法能明显降低系统的随机涨落和显著改善系统的非线性反应性态. 相似文献
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《中国测试》2019,(11):101-107
针对当前对低压电力线载波通信调制信号识别过程中出现选取特征困难、选取特征不恰当、识别准确率低的问题,提出特征选择——支持向量机(support vector machine, SVM)的调制信号识别方法。通过采集电力线载波通信芯片发送的调制信号样值,经预处理去噪、滤波后选取调制信号多个特征,使用特征选择工具——FEAST,从多个特征集中找出最能标识数据特征集的特征子集,利用SVM方法对特征子集进行判决归类,并将分类识别后的结果与传统神经网络进行比较。仿真结果表明,所提出的方法选取特征与原有方法相比更为简单准确,其识别准确率较传统神经网络有明显提升,调制信号识别准确率达到98%以上,且收敛速度相比更快,可为多特征下低压电力线载波通信调制信号识别提供参考。 相似文献
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The Duffing oscillator under combined periodic and random excitations is investigated by a simple technique. The system response is separated into the deterministic and random parts governed by two coupled differential equations. The couple relation is expressed through varying on time coefficients which are approximately replaced by their averaging values over one period. This simplification yields that the two coupled differential equations can be solved by averaging and equivalent linearization methods. The mean-square response of the system is compared with the numerical results obtained by the finite element and Monte Carlo simulation methods. The results obtained show the interaction between the periodic and random excitations on the system response. 相似文献
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This study carried out investigations on the bifurcation characteristics of a Duffing–Van der Pol (DVDP) oscillator subjected to white noise excitations. Dynamical (or D-) bifurcations are characterised by dramatic changes in the dynamical behaviour leading to topological changes in the phase portrait. An additional mode of bifurcation - phenomenological (or P-) bifurcation, is observed in stochastically excited systems when the stationary joint probability density function of the state variables undergo topological changes in the probability space. While D-bifurcation analysis is quantified in terms of the sign changes in the largest Lyapunov exponent, P-bifurcation analysis is usually qualitative and through visual inspection. In this study, a new quantitative measure for P-bifurcations based on the Shannon entropy is proposed. A comparison of the parameter regimes of the noisy DVDP oscillator identified by the three bifurcation methodologies have been presented. 相似文献
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《Probabilistic Engineering Mechanics》1999,14(1-2):83-95
This paper discusses the random response of a non-linear Duffing oscillator subjected to a periodic excitation with random phase modulation. Effects of uncertainty in the periodic excitation and level of the system non-linearity on the response moments and non-Gaussian nature of the response caused by both the system non-linearity and the non-Gaussian loading are investigated. Results are presented in terms of the second- and the fourth-order moments as well as the excess factor of the response and some results are compared with those from the Monte Carlo simulation. An iterated linearisation technique is proposed to improve the accuracy of the numerical results for strongly non-linear systems. 相似文献
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The purpose of this paper is to approximate the dynamics of a non-linear oscillator with multiple static equilibrium excited by a white noise. An approach based on asymptotic expansions of dynamical systems driven by weak random perturbations is introduced. To illustrate the method, the Duffing oscillator with two symmetric potential wells is considered. An equivalent locally linear oscillator, which provides a good approximation of the dynamics of the studied oscillator, is obtained. This last approximation can be considered as a local linearization. 相似文献