A statistical parametric approach to speech synthesis based on hidden Markov models (HMMs) has grown in popularity over the last few years. In this approach, spectrum, excitation, and duration of speech are simultaneously modeled by context-dependent HMMs, and speech waveforms are generated from the HMMs themselves. Since December 2002, we have publicly released an open-source software toolkit ...

Stability analysis of nonlinear control systems using Lypunov’s direct method is reported in this paper. A general nonlinear controlled system and two different types of controllers are examined for stability analysis. The first category is the parametric controller. Importance of parametric controllers is illustrated through examples of various engineering systems. A general control algorithm ...

We report on a detailed experimental investigation of interbranch parametric scattering processes in onedimensional semiconductor microcavities. Band dispersion and corresponding far field emission patterns are studied by polarization resolved and power dependence measurements under resonant and non-resonant excitation at normal incidence. We demonstrate the realization of optical parametric os...

We investigate the dynamics of a delayed nonlinear Mathieu equation: ẍ + (δ + εα cos t)x + εγ x = εβx(t − T ) in the neighborhood of δ = 1/4. Three different phenomena are combined in this system: 2:1 parametric resonance, cubic nonlinearity, and delay. The method of averaging (valid for small ε) is used to obtain a slow flow that is analyzed for stability and bifurcations. We show that the 2:1...

The excitation spectrum around the pump-only stationary state of a polariton optical parametric oscillator in semiconductor microcavities is investigated by time-resolved photoluminescence. The response to a weak pulsed perturbation in the vicinity of the idler mode is directly related to the lifetime of the elementary excitations. A dramatic increase of the lifetime is observed for a pump inte...

This study presents an analytical approach to the dynamic problem encountered by a rotating electric machine supported by nonlinear bearings with damping properties subjected to a forcing excitation caused by an unbalanced force and a parametric excitation caused by an axial thrust. The method employed in this analytical study is the Optimal Variational Iteration Method (OVIM), which proves to ...

A model of a multidimensional system, consisting of a chain of nonlinearly coupled chaotic pendula subjected to a chaos-inducing harmonic parametric excitation, is introduced. The nonlinear dynamics of the chain is analyzed with attention to the synchronization phenomena. The control of chaos (suppression and enhancement) through the introduction of a second periodic excitation is investigated,...

We demonstrate the creation of vortices in a macroscopically occupied polariton state formed in a semiconductor microcavity. A weak external laser beam carrying orbital angular momentum (OAM) is used to imprint a vortex on the condensate arising from the polariton optical parametric oscillator (OPO). The vortex core radius is found to decrease with increasing pump power, and is determined by po...

We study the response of a large array of coupled nonlinear oscillators to parametric excitation, motivated by the growing interest in the nonlinear dynamics of microelectromechanical and nanoelectromechanical systems (MEMS and NEMS). Using a multiscale analysis, we derive an amplitude equation that captures the slow dynamics of the coupled oscillators just above the onset of parametric oscilla...

The use of periodic excitation signals in identiication experiments is advocated. With periodic excitation it is possible to separate the driving signals and the disturbances , which for instance implies that the noise properties can be independently estimated. In the paper a non-parametric noise model, estimated directly from the measured data, is used in a compensation strategy applicable to ...