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Model convergence

The precision of time series predictions far into the future may be limited. Time series analysis requires a relatively large amount of data. Precautions are necessary if the time intervals are not approximately equal (9). However, when enough data can be collected, for example, by an automated process, then time series techniques offer several distinct advantages over more traditional statistical techniques. Time series techniques are flexible, predictive, and able to accommodate historical data. Time series models converge quickly and require few assumptions about the data. [Pg.98]

The experimental errors on the %DE measurements are estimated to be between 1 and 2 %, taking into account a relative long time span and the involvement of different lab-workers. As indicated by Table 2 the best models converge to an RMSEP of 1.5 % to refine the models further the experimental chemical errors have to be thoroughly investigated. [Pg.546]

Figure 4. Hierarchy of the SF models. Similar to the non-SF SR methods, the SF models converge to the exact n-electron wavefunction when the spin-flipping operator 0 includes up to n-tuple excitations. For example, the SF-CCSD model... Figure 4. Hierarchy of the SF models. Similar to the non-SF SR methods, the SF models converge to the exact n-electron wavefunction when the spin-flipping operator 0 includes up to n-tuple excitations. For example, the SF-CCSD model...
All the models converge at very low and very high temperatures but, because they take into account varying degrees of short-range order, they give a different... [Pg.204]

The difference between the Markov model lineshapes and those from the Smoluchowski model is particularly pronounced when the diffusion coefficient is of the order of the quadrupole coupling constant. In the limit of large diffusion coefficients, the two models converge, and in the limit of low diffusion coefficients, the spectra are dominated by small-amplitude oscillations within potential wells, which can be approximately modelled by a suitable Markov model. This work strongly suggests that there could well be cases where analysis of powder pattern lineshapes with a Markov model leads to a fit between experimental and simulated spectra but where the fit model does not necessarily describe the true dynamics in the system. [Pg.6]

FIGURE 5.18 PCR (o), PLS ( ), and simplex () harmonious plots for NIR analysis of moisture in soy samples. The PCR and PLS 1 factor models are in the lower right comer, and the respective models are 8 and 7 factors in the upper left comer. The simplex models converged to RR and GRR models. The RMSEC values are with n — 1 degrees of freedom. [Pg.153]

When studying the stability of the steady-state, time-dependent calculations are needed (see [7]). It can also be used as a simple method to compute the steady-state solution. A time-dependent approach using the Lesaint-Ravian technique for the normal stress components and the Baba-Tabata scheme for the shear stress component is developed by Saramito and Piau ([34]). This method allows one to obtain rapidly stationary solutions of the PTT models. Convergence with mesh refinement is obtained as well as oscillation-free solutions. [Pg.248]

We can conclude that observational cosmology offers strong evidences favoring the existence of processes, determined by new physics, and the experimental physics approaches to their investigation. So modern cosmology and physics beyond the standard model converge in their mutual relationship. [Pg.81]

Under the parameter selections and initialization values described here, the model converges at approximately 5,200 trials. [Pg.368]

In the limits of high and low Dg (high and low pressure) the model outlined here approaches condensed phase controlled burning regimes, independent of Eg. That is, both Eg I and Eg I models converge to the same set of equations. In the low Dg (low pressure) limit, gas conductive heat feedback becomes negligible compared with condensed phase heat release and/or radiative heat feedback, and m and Ts are given by Eqs. (11) and (15) with qc 0 (xg -> >). [Pg.244]

In this example, the matrix F is unstable (eigenvalues= 0,1 ), but = = Hy. Thus, the Kalman filter for this model converges to a steady state, and so the framework in this paper can still be used to devise and characterize appropriate classes of stationary inventory policies for the ARIMA(0,1,1) case. In fact, a detailed treatment of this model is provided in Graves (1999). [Pg.410]

Efforts to differentiate between these two models through statistical analysis of the pentad distributions have been inconclusive. Figure 2.12 summarizes one such investigation with i-1, which concluded that the site epimerization model and the alternating model converged to the same enantiofacial selectivity parameter upon minimization of the RMS (root mean square) error in comparison with the observed pentad populations. If the site epimerization model applies, then... [Pg.55]

The true system whose response we are observing is non-linear, however the model that we are fitting is linear. To what values will the maximum likelihood estimates of the coefficients for the assumed linear model converge "... [Pg.260]

The effectiveness of cell kill by radiation, either in vitro or in vivo, is measured by the cell survival or dose survival curve [7]. In Figure 8.1 are represented the typical curves for cells exposed to X-radiation under N2 and under O2. A number of mathematical models have been used to describe these curves and these have been compared [8, 9]. Most models converge at high doses but they give disparate results at low doses. This is of importance because, whereas doses of 300—3000 rads are routinely used to construct these curves for X-rays, the clinically relevant doses are up to 200 rads, with multiple doses over the period of treatment. Accurate description of the survival curve at low doses is essential for prediction of clinical behavior. Two of the most common models used are the multi-target model where 5 = 1 -(1 - j-jo], and the a model, where... [Pg.184]


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