Browsing by Subject "Steady-state"

Now showing 1 - 3 of 3

Open Access
A Deterministic Analysis of an Online Convex Mixture of Expert Algorithms
(IEEE, 2014-07) Ozkan, H.; Donmez, M. A.; Tunc, S.; Kozat, S. S.
We analyze an online learning algorithm that adaptively combines outputs of two constituent algorithms (or the experts) running in parallel to model an unknown desired signal. This online learning algorithm is shown to achieve (and in some cases outperform) the mean-square error (MSE) performance of the best constituent algorithm in the mixture in the steady-state. However, the MSE analysis of this algorithm in the literature uses approximations and relies on statistical models on the underlying signals and systems. Hence, such an analysis may not be useful or valid for signals generated by various real life systems that show high degrees of nonstationarity, limit cycles and, in many cases, that are even chaotic. In this paper, we produce results in an individual sequence manner. In particular, we relate the time-accumulated squared estimation error of this online algorithm at any time over any interval to the time-accumulated squared estimation error of the optimal convex mixture of the constituent algorithms directly tuned to the underlying signal in a deterministic sense without any statistical assumptions. In this sense, our analysis provides the transient, steady-state and tracking behavior of this algorithm in a strong sense without any approximations in the derivations or statistical assumptions on the underlying signals such that our results are guaranteed to hold. We illustrate the introduced results through examples. © 2012 IEEE.
Open Access
Light-harvesting positively-charged nanocrystals for strong energy transfer to dye molecules
(IEEE, 2008-11) Mutlugün, Evren; Demir, Hilmi Volkan
In this work, water-soluble positively-charged CdSe/ZnS core/shell nanocrystals were presented, serving as light harvester (donor) for strong energy transfer to rhodamine B dye molecules (acceptor) in solution. In accordance with photoluminescence (PL) characterization, the emission of rhodamine B was enhanced at the laser pump wavelength, which may open up possibilities for lasers based on dye molecules pumped at different wavelengths.
Open Access
A new method for the steady-state analysis of periodically excited nonlinear circuits
(Institute of Electrical and Electronics Engineers, 1996-12) Celik, M.; Atalar, Abdullah; Tan, M. A.
We propose a new method for the steady state analysis of periodically excited nonlinear microwave circuits. It is a modified and more efficient form of Newton-Raphson iteration based harmonic balance (HB) technique. It solves the convergence problems of the HB technique at high drive levels. The proposed method makes use of the parametric dependence of the circuit responses on the excitation level. It first computes the derivatives of the complex amplitudes of the harmonics with respect to the excitation level efficiently and then finds the Pade approximants for the amplitudes of the harmonics using these derivatives.