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Your search keyword '"Kou, K.P."' showing total 16 results
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16 results on '"Kou, K.P."'

12. Probability density function solution of nonlinear oscillators subjected to multiplicative Poisson pulse excitation on velocity

Author

Zhu, H.T., Er, G.K., Iu, V.P., and Kou, K.P.

Subjects
Combinatorial probabilities -- Research, Geometric probabilities -- Research, Probabilities -- Research, Oscillators (Electronics) -- Mechanical properties, Oscillators (Electronics) -- Testing, Poisson processes -- Research, Speed -- Research, Dynamic testing -- Methods, Science and technology
Abstract

The stationary probability density function (PDF) solution of the stochastic responses is derived for nonlinear oscillators subjected to both additive and multiplicative Poisson white noises. The PDF solution is governed by the generalized Fokker--Planck--Kolmogorov (FPK) equation and obtained with the exponential-polynomial closure (EPC) method, which was originally proposed for solving the FPK equation. The extended EPC solution procedure is presented for the case of Poisson pulses in this paper. In order to evaluate the effectiveness of the solution procedure, nonlinear oscillators are investigated under multiplicative Poisson white noise excitation on velocity and additive Poisson white noise excitation. Both weakly and strongly nonlinear oscillators are considered, respectively. In the numerical analysis, both the unimodal and bimodal stationary PDFs of oscillator responses are obtained with the EPC method and Monte Carlo simulation. Compared with the simulation results, good agreement is achieved with the presented solution procedure in the case of the polynomial degree being 6, especially in the tail regions of the PDFs of the system responses. [DOI: 10.1115/1.4000385] Keywords: nonlinear, oscillator, generalized FPK equation, probability density function, Poisson white noise

Published
2010

13. Probabilistic solution of nonlinear oscillators under external and parametric Poisson impulses

Author

Er, G.K., Zhu, H.T., Iu, V.P., and Kou, K.P.

Subjects
Monte Carlo method -- Analysis, Aerodynamics -- Analysis, Oscillators (Electronics) -- Properties, Oscillators (Electronics) -- Analysis, Aerospace and defense industries, Business
Abstract

This paper deals with the stationary probability density function solution of the dynamic response for nonlinear oscillators excited by Poisson impulses. The probability density function solution is governed by the generalized Fokker--Planck--Kolmogorov equation. The exponential-polynomial closure method is used to obtain an approximate solution to the generalized Fokker--Planck--Kolmogorov equation. To evaluate the effectiveness of the exponential-polynomial closure method in the case of Poisson excitations, Duffing oscillators, van der Pol oscillators, and an additional nonlinear oscillator excited by external and parametric Poisson impulses with different levels of nonlinearity in stiffness and damping are studied. The numerical results show good agreement with the probability distribution obtained with Monte Carlo simulations including the tail regions, which is of significance for reliability analyses. DOI: 10.2514/1.36556

Published
2008

16. Trip-pair based clustering model for urban mobility of bus passengers in Macao

Author

Ku, W.K., Kou, K.P., Lam, S.H., and Wong, K.I.

Abstract

ABSTRACTPublic transit is a major mode of urban mobility in Macao, a compact and populous city in China. Public transit ridership is related to round-the-clock shift-based work arrangements in the gaming industry. Smartcards that are used in transit fare collection are a vital data source for understanding the travel patterns and characteristics of transit passengers. However, transactional information from single data sources is fragmented, hindering the extraction of mobility patterns. We proposed a trip-pair-based clustering model that extracts the within-day mobility patterns of bus riders. DBSCAN is employed to filter scattered trips and hierarchical agglomerative clustering to identify clusters. Using a six-month smartcard dataset from Macao, categories of bus passengers were identified. Travel patterns exist with irregular, one-way, and round-trip passengers, and shift workers. The unique shift-based work-life and mixed travel modes in Macao can serve as an example of dense and compact city travel for smart cities.

Published
2023
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