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Indirect hard modeling

Another approach for data processing involves simulation of pure spectra. These model spectra are then taken for a quantitative description of the mixture spectra. This procedure is referred to as indirect hard modelling (IHM). Obviously, changes in line shape, line width, and chemical shift may occur as function of concentration and due to system imperfections which are taken into account by IHM. The peaks are modelled by Voigt-functions with variable Gaussian to exponential ratio. The main advantage of IHM is that it allows a limited physical interpretation of the models. Further, unlike PLS based methods, IHM only requires reference spectra of the pure compounds, reducing the calibration effort drastically. [Pg.53]

The described approaches are often named hard modeling as they rely on physicochemical information that is sample specific. A modification of the hard modehng became available indirect hard modehng (IHM) [23, 24] considers each... [Pg.421]

Note that eq. (36.5) is a collection of many univariate multiple regression models for each wavelength j the multiple regression of the corresponding spectral channel , i.e. Sj, on the concentration matrix C yields a vector of regression coefficients, ky (the yth column of K). For K to be estimable C C must be invertible, i.e. the number of calibration standards should at least be as large as the number of analytes. It is clearly not possible to obtain, directly or indirectly, say 3 pure spectra from recording the spectra of just 1 or 2 standards of known composition. In practice, the condition n>p, or more precisely rank(C)=p, is hardly a restriction. [Pg.354]

Pressure for substitution also existed for the material PVC due to the public PVC discussion and also indirectly due to the DIRECTIVE 2000/53/EC on end-of life vehicles. Distnantlable nndeibody hard shells made of polypropylene are snit-able to solve these problems. However, the design of the nnderbody has to be adapted to the use of a hard shell, which can ultimately only be achieved in combination with a change of model. [Pg.72]

More complex integrated PK/PD models are necessary to link and account for a possible temporal dissociation between the plasma concentration and the observed effect. Four basic attributes may be used to characterize PK/PD models First, the link between measured concentration and the pharmacological response mechanism that mediates the observed effect (direct versus indirect link) second, the response mechanism that mediates the observed effect (direct versus indirect response) third, the information used to establish the link between measured concentration and observed effect (hard versus soft link) and, fourth, the time dependency of the involved PD parameters (time variant versus time invariant) (Danhof et al., 1993 Steimer et al., 1993 Aarons, 1999 Lees et al., 2004). The expanded and early use of PK/PD modeling in drug discovery and development is highly beneficial for increasing the success rate of drug discovery and development and will most likely improve the current state of applied therapeutics. [Pg.101]

The scenario, at first glance, seems to escape the standard experimental approach, namely comparison of the outcome from a set of observations with predictions based on a fittable model The control of all degrees of freedom of a quantum object is hard to achieve. Moreover, any measurement requires the interaction of quantum object and classical meter, and the object is supposed to suffer intolerable back action. However, there is a loophole based on "indirect null-result" measurements [10]. Fortunately enough, there are predictions, stated more than half a century ago, that may be matched with the results of measurements on a well-isolated and available type of microphysical system. A very counterintuitive prediction proclaims The evolution of a measured quantum system becomes slowed down, or, in the extreme, even completely frustrated [11,12]. This prediction, the "quantum Zeno effect" (QZE) [13], has evoked a wealth of theoretical work [14] but very little, and highly controversial experimental evidence. [Pg.10]

In order to maximize the return on the investment required to conduct physical dynamic tests on full-scale structures, system identification methods must be used to allow the data collected during the tests to yield a maximum amount of useful information about the properties of the tested structures. System identification is the inverse problem of using the measured dynamic properties of full-scale or model structures to identify indirectly their important structural characteristics. The system identification literature is quite extensive. Bekey (1970) published an introduction to system identification and Rodeman and Yao (1973) have prepared a bibliography of the literature prior to 1973. Hard and Yao (1977) have also prepared a recent... [Pg.398]

While we are not aware of any hard data to support this assertion, many within the operations research community have argued that one of the reasons for the success of decision support models in supply chain management is the fact that ERP systems have made available the (previously unavailable) data that these models require. This is certainly quite possible. In addition, many stand-alone decision support systems make use of data from ERP systems, but are not integrated with the ERP system and not viewed as ERP decision support systems. This would therefore clearly be an indirect ERP benefit. [Pg.751]

The final phase of the accident sequence and the last link in the chain reaction is costs. All contacts result in some form of loss. Losses could include both direct and indirect costs of the accident. Model 2.7 shows the iceberg effect where the property damage costs could be 60 to 100 times greater than the direct costs. The totally hidden costs of the accident also are losses that are hard to determine, but which exists nevertheless. [Pg.34]

The situation is different for the indirect packing effects. They can be calculated by the ab initio method if a structural model predicts the packing distortions with sufficient precision. Naturally, it will be hard to develop such a geometric-statistical model, but once the geometries are known they may be used as an input for the IGLO calculations and thus for the simulation of the -NMR spectrum. [Pg.63]

The first point is described in Section 11.4 using the thermodynamics theory and in the present section with Palieme s model. The second point is also largely described in the present section, whereas the last point is hard to describe as there is a lack of investigations available in the literature because interfacial adhesion is difficult to evaluate directly. Mainly, an indirect method, such as the evaluation of the mechanical properties is used. [Pg.228]

A collection of hard, identical spheres is the simplest possible model system that undergoes a first order phase transition. For low packing fractions the particles are in a liquid state, but when the packing fractions exceeds a value of 49.4% a ordered solid state becomes more stable. This was first shown in computer simulations by Hoover and Ree [27] in 1968. The experimental realization of a colloidal suspension that closely mimics the phase behavior of hard spheres followed about 20 years later and was a milestone in soft matter physics [28, 29]. More recently the phase transition kinetics of hard sphere colloids has been studied extensively in experiments [5, 30, 31]. However as mentioned in the introduction the interpretation of the data with CNT was rather indirect. [Pg.164]


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See also in sourсe #XX -- [ Pg.421 ]




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Hard-modelling

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