Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Parametric models only

On this level, no entities of type MACRO or FORMAL PARAMETER and ROUTINE are available. [Pg.155]


In terms of models, they fall into three categories parametric, nonparametric, and semiparametric. A parametric model only contains a finite number of parameters. One of the simplest examples of a parametric statistical model is the following ... [Pg.188]

Probably the first major publication of a process model for the autoclave curing process is one by Springer and Loos [14]. Their model is still the basis, in structure if not in detail, for many autoclave cure models. There is little information about results obtained by the use of this model only instructions on how to use it for trial and error cure cycle development. Lee [16], however, used a very similar model, modified to run on a personal computer, to do a parametric study on variables affecting the autoclave cure. A cure model developed by Pursley was used by Kays in parametric studies for thick graphite epoxy laminates [18]. Quantitative data on the reduction in cure cycle time obtained by Kays was not available, but he did achieve about a 25 percent reduction in cycle time for thick laminates based on historical experience. A model developed by Dave et al. [17] was used to do parametric studies and develop general rules for the prevention of voids in composites. Although the value of this sort of information is difficult to assess, especially without production trials, there is a potential impact on rejection rates. [Pg.455]

Usually, a mathematical model simulates a process behavior, in what can be termed a forward problem. The inverse problem is, given the experimental measurements of behavior, what is the structure A difficult problem, but an important one for the sciences. The inverse problem may be partitioned into the following stages hypothesis formulation, i.e., model specification, definition of the experiments, identifiability, parameter estimation, experiment, and analysis and model checking. Typically, from measured data, nonparametric indices are evaluated in order to reveal the basic features and mechanisms of the underlying processes. Then, based on this information, several structures are assayed for candidate parametric models. Nevertheless, in this book we look only into various aspects of the forward problem given the structure and the parameter values, how does the system behave ... [Pg.451]

This chapter endeavors to show that a population PK/PD approach to the analysis of count data can be a valuable addition to the pharmacometrician s toolkit. Nonlinear mixed effects modeling does not need to be relegated to the analysis of continuously valued variables only. The opportunity to integrate disease progression, subject level covariates, and exposure-response models in the analysis of count data provides an important foundation for understanding and quantifying drug effect. Such parametric models are invaluable as input into clinical trial and development path simulation projects. [Pg.717]

The procedures outlined above have a practical use, but it should be realized that the parametric models are almost entirely empirical. Experimental uncertainties are also involved since solubility measurements are not very accurate. Solubility loops described by the models only indicate the limits of compatibility and always Include doubtful observations. [Pg.210]

A semiclassical model to calculate the probability pvl that a molecule follows a diabatic pathway, by retaining the electronic stmcture of the initial electronic state as it passes through an avoided crossing, was developed independently in 1932 by Landau and by Zener.154 In the Landau Zener model, the nuclear movements are described classically, that is, nuclear motion enters parametrically and only a single reaction coordinate, as shown in diagram in Figure 2.27, is considered. In the Landau Zener expression given in Equation 2.53 ... [Pg.69]

As recalled above, the SoS r-nuclide abundance distribution is obtained by subtracting from the observed SoS abundances those predicted to originate from the s-process. These predictions are classically based on a parametric model, referred to as the canonical exponential model initially developed by [33], and which has received some refinements over the years (e.g. [34]). This model assumes that stellar material composed only of iron nuclei is subjected to neutron densities and temperatures that remain constant over the whole... [Pg.297]

Chapters 3 and 4 presented two Bayesian methods to handle output-only measurements if the excitation can be modeled by stochastic process with a prescribed parametric model. [Pg.189]

Changing the size of the square in parametric modeling, on the other hand, only requires you to change the dimension. [Pg.166]

Note that it depends on the number of sensors and where they are placed whether parametric faults can be isolated. Under the assumption of a single fault hypothesis and N given sensors, the maximum number of parameter faults that can be isolated is equal to 2 — 1. However, often, the number of sensors, N, is less than the number of component parameters, p, so that the FSM is not quadratic. Some component parameters may have the same component fault signature (in some modes) so that faults in these parameters cannot be isolated by inspection of the all-mode FSM. Clearly, additional sensors may improve the isolability of faults. But detectors can be placed in a model only for those variables that are accessible by real sensors in the real system. Even if quantities can be measured, cost considerations may suggest to limit the number of real sensors. For illustration, inspection of ARRs (4.6)-(4.8) yields the FSM in Table 4.1. [Pg.76]

Magnetic dipole-derived intensity, which requires no parity mixing, is calculated in absolute units from the matrix elements of the magnetic moment operator and requires no additional parametrization. For d-d spectra, this source is generally unimportant. However, for f-f spectra, magnetic dipole-derived intensity must be included. As the electric dipole model only provides a relative intensity scale, a scaling parameter for the two sources must be introduced. [Pg.672]

The approaches discussed so far suggest that silica aerogels have complexly networked structures that the final properties depend not only on the topological features but also on the process parameters. For certain, most of the authors used density as the single most important physical property in their analysis. Hence, the models and proposed theories could only provide an estimate of the real values. Nevertheless, both the cellular foam and parametric models revealed a certain... [Pg.54]

Psychology The associations between the cumulative effects of seven benzodiazepines and the risk of fall-related injuries were assessed in a cohort study in 23,765 new users of benzodiazepines, aged 65 years and older, in Canada, between 1990 and 1994 [4 ]. Only users of a particular benzodiazepine (alprazolam, bromazepam, chlordiazepoxide, clonazepam, flurazepam, lorazepam and temazepam) were included in this study. The authors used both conventional parametric models (ciurent exposure, unweighted sum of past exposures) and the novel, flexible weighted cumulative exposure models. This study highlighted the importance of recognising that the effects of some benzodiazepines may cumulate over time. [Pg.55]

Parametric models are more or less white box or first principle models. They consist of a set of equations that express a set of quantities as explicit functions of several independent variables, known as parameters . Parametric models need exact information about the inner stmcture and have a limited number of parameters. For instance, for the description of the dynamics, the order of the system should be known. Therefore, for these models, process knowledge is required. Examples are state space models and (pulse) transfer functions. Non-parametric models have many parameters and need little information about the inner stmcture. For instance, for the dynamics, only the relevant time horizon shoirld be known. By their stmcture, they are predictive by nature. These models are black box and can be constructed simply from experimental data. Examples are step and pulse response functions. [Pg.21]

In this book, we have only considered using MCMC methods to find the posterior probability distribution for a given parametric model. Carlin and Chib (1995) noted that MCMC approach is so flexible and easy to use that the class of candidate models... [Pg.269]


See other pages where Parametric models only is mentioned: [Pg.166]    [Pg.155]    [Pg.166]    [Pg.155]    [Pg.187]    [Pg.244]    [Pg.138]    [Pg.228]    [Pg.92]    [Pg.40]    [Pg.538]    [Pg.184]    [Pg.246]    [Pg.538]    [Pg.735]    [Pg.3992]    [Pg.81]    [Pg.189]    [Pg.77]    [Pg.325]    [Pg.92]    [Pg.3]    [Pg.281]    [Pg.175]    [Pg.74]    [Pg.162]    [Pg.166]    [Pg.76]    [Pg.446]    [Pg.8]    [Pg.298]    [Pg.433]    [Pg.168]    [Pg.250]    [Pg.89]   


SEARCH



Parametric

Parametric Model

Parametric modeling

Parametrization

Parametrized Model

© 2024 chempedia.info