The evolution of the quintessence in various stages of the universe, the radiation, matter-, and quintessence-dominated, is closely related with the tracking behavior and the deceleration parameter of the universe. We gave the explicit relation between the equation-of-state of the quintessence in the epoch of the matter-quintessence equality and the inverse power index of the quintessence poten...

We aimed to examine the extent to which inaccurate assumptions for nuisance parameters used to calculate sample size can affect the power of a randomized controlled trial (RCT). In a simulation study, we separately considered an RCT with continuous, dichotomous or time-to-event outcomes, with associated nuisance parameters of standard deviation, success rate in the control group and survival ra...

There are typically uncertain parameters in power system models. This paper presents a computational method for evaluating the effect of parameter uncertainty on the dynamic behaviors of power systems. The effect of parameter uncertainty is represented by system trajectory or performance bounds around ccepted 23 April 2008 vailable online 5 June 2008 eywords: arameter uncertainty uccessive line...

Fuel cells directly convert chemical energy into electrical power using electrochemical reactions. Solid oxide fuel cell (SOFC) is one of the high-temperature fuel cells that propose a promising future from the standpoint of power generation. In this study, optimization of an SOFC system is performed using Taguchi approach after verification of the model in compare with experimental results. Cu...

Simulations are used to check the probability of detecting a time-varying equilibrium correction by applying the existing tests of no cointegration and parameter constancy. Smooth-transition regressions are chosen to describe the nonlinearity, and the Johansen cointegration test and the Lin and Teräsvirta parameter constancy test are applied. It turns out that both tests perform well separately...

Original scientific paper Accurate estimation of harmonic parameter is an important task in signal processing of power system. A new class of flat-top windows is proposed, which is generated by self-convolutions of the fast-decaying minimum-sidelobe flat-top (FDMS-FT) window in the time-domain. The mainlobe and sidelobe features of the new window are studied. In addition, to improve the flatnes...

In this paper, the different parameter estimation methods such as maximum likelihood method, least square method, weighted least square method, moments method, the method based on quantiles and maximum spacing method for the Weibull distribution which are widely accepted in wind power studies are presented and discussed. The effect of the selecting parameter estimation method on the estimation ...

as is well known, estimating parameters of the tree-parameter weibull distribution is a complicated task and sometimes contentious area with several methods vying for recognition. weibull distribution involves in reliability studies frequently and has many applications in engineering. however estimating the parameters of weibull distribution is crucial in classical ways. this distribution has t...