Big Chemical Encyclopedia

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

Articles Figures Tables About

Model deterministic models

Currently, the landslide hazard spatial prediction methods can be divided into qualitative methods and quantitative methods. As we all know qualitative forecasting method mainly depends on the subjective experience and the predicted accuracy of qualitative methods is lower than it of quantitative methods. So the qualitative methods have been gradually replaced by the quantitative methods. Quantitative models can be divided into statistic analysis models, deterministic models, probabilistic model, fuzzy information optimization processing and neurd network models. [Pg.813]

To carry out the above mentioned, appear diverse types of models that set up methodologies to represent the system (Bause Kritzinger, 2002 Buzacott Shanthikumar, 1993 Fuqua, 2003 Schryver et al, 2012 Zio Pedroni, 2010). Some of these models are mathematical models, stochastic models, deterministic models, simulation models for discrete events, Markov chains, among others. Each of these models, achieve different representation grades of the system, so its correct selection is relevant to accomplish with the desired objectives. On the other hand, each model possesses different requirements of information and development times, since many times is not possible to apply any model to a specific system. [Pg.1915]

Standard procedures that are used for testing of construction materials are based on square pulse actions or their various combinations. For example, small cyclic loads are used for forecast of durability and failure of materials. It is possible to apply analytical description of various types of loads as IN actions in time and frequency domains and use them as analytical deterministic models. Noise N(t) action as a rule is represented by stochastic model. [Pg.189]

The literature of science is replete with models. This variety enables one to make some interesting observations. Thus, for example, one rarely regards models as unique or absolute, although, through the choice of a specific one (e.g., a differential equation), unique solutions to problems may be obtained. A model is formulated to serve a specific purpose. Some models may be suitable for generalization, others may not be. These generalizations are more profitably made as extrapolations for scientific purposes, and occasionally as useful philosophical observations. A model must be flexible to absorb new information, and, hence, stochastic processes have broader and richer applicability than deterministic models. [Pg.251]

Chang, L., Deterministic Model for Line-Contact Partial Elasto-Hydrodynamic Lubrication, Tribal. Int., Vol. 28, No. 2,1995,pp. 75-84. [Pg.145]

Figure 5.3-19. Deterministic models based on physicochemical models according to the type... [Pg.233]

Model formulation. After the objective of modelling has been defined, a preliminary model is derived. At first, independent variables influencing the process performance (temperature, pressure, catalyst physical properties and activity, concentrations, impurities, type of solvent, etc.) must be identified based on the chemists knowledge about reactions involved and theories concerning organic and physical chemistry, mainly kinetics. Dependent variables (yields, selectivities, product properties) are defined. Although statistical models might be better from a physical point of view, in practice, deterministic models describe the vast majority of chemical processes sufficiently well. In principle model equations are derived based on the conservation law ... [Pg.234]

In general, there is no frequent need to design new batch plants. For all the above listed factors deterministic models for plant design will be of limited significance. Plant retrofitting (replacement of equipment, installation of new equipment, and elimination of old equipment) is more often encountered in the field of batch plants. The uncertainty then is much lower than for the design of new plants. [Pg.506]

In summary, models can be classified in general into deterministic, which describe the system as cause/effect relationships and stochastic, which incorporate the concept of risk, probability or other measures of uncertainty. Deterministic and stochastic models may be developed from observation, semi-empirical approaches, and theoretical approaches. In developing a model, scientists attempt to reach an optimal compromise among the above approaches, given the level of detail justified by both the data availability and the study objectives. Deterministic model formulations can be further classified into simulation models which employ a well accepted empirical equation, that is forced via calibration coefficients, to describe a system and analytic models in which the derived equation describes the physics/chemistry of a system. [Pg.50]

In this fashion, we extend our deterministic model with a prediction horizon of H = 2 to a multi-stage model. The multi-stage tree of the possible outcomes of the demand within this horizon (starting from period i = 1) with four scenarios is shown in Figure 9.5. Each scenario represents the combination fc out of the set of all combinations of the demand outcomes within the horizon. The production decision x has to be taken under uncertainty in all future demands. The decision xj can react to each of the two outcomes of d i, but has to be taken under uncertainty in the demand di. The corrective decisions are explicitly modeled by replacing xj by two variables 2,1 and 2.2 ... [Pg.192]

As a preliminary step, we investigate the result of using a deterministic model, the expected value problem (EV). For the first-stage solution obtained from EV, the objective of the 2S-MILP is EEV = —12.00. [Pg.209]

Wet-weather processes are subject to high variability. A simple deterministic model result in terms of the impacts on the water quality is out of scope. From a modeling point of view, a stochastic description is a realistic solution for producing relevant results. Furthermore, an approach based on a historical rainfall series as model input is needed to establish extreme event statistics for a critical CSO impact that can be compared to a water quality criterion. In terms of CSO design including water quality, this approach is a key point. [Pg.225]

Deterministic vs. stochastic an optimization problem can be based on deterministic parameters assuming certain input data or reflect uncertainty including random variables in the model in value chain management deterministic parameters are the basic assumptions extended models also model specifically uncertain market parameters such as demand and prices as stochastic parameters based on historic distributions in chemical commodities, this approach has some limitations since prices and demand are not normally distributed but depend on many factors such as crude oil prices (also later fig. 37). [Pg.70]

Deterministic models that are non-linear in c will be limited to specific applications. For example, in the generalized IEM (GIEM) model (Tsai and Fox 1995a Tsai and Fox 1998), which is restricted to binary mixing, the mixture fraction appears non-linearly 61... [Pg.286]

E. Stochastic Versus Deterministic Models for Circadian Rhythms The Cell-Cycle Clock Newly Discovered Cellular Rhythms... [Pg.253]

Only deterministic models for cellular rhythms have been discussed so far. Do such models remain valid when the numbers of molecules involved are small, as may occur in cellular conditions Barkai and Leibler [127] stressed that in the presence of small amounts of mRNA or protein molecules, the effect of molecular noise on circadian rhythms may become significant and may compromise the emergence of coherent periodic oscillations. The way to assess the influence of molecular noise on circadian rhythms is to resort to stochastic simulations [127-129]. Stochastic simulations of the models schematized in Fig. 3A,B show that the dynamic behavior predicted by the corresponding deterministic equations remains valid as long as the maximum numbers of mRNA and protein molecules involved in the circadian clock mechanism are of the order of a few tens and hundreds, respectively [128]. In the presence of molecular noise, the trajectory in the phase space transforms into a cloud of points surrounding the deterministic limit cycle. [Pg.272]

Rational air pollution control strategies require the establishment of reliable relationships between air quality and emission (Chapter 5). Diffusion models for inert (nonreacting) agents have long been used in air pollution control and in the study of air pollution effects. Major advances have been made in incorporating the complex chemical reaction schemes of photochemical smog in diffusion models for air basins. In addition to these deterministic models, statistical relationships that are based on aerometric data and that relate oxidant concentrations to emission measurements have been determined. [Pg.5]

There are many ways of categorizing air quality models. One differentiation is between statistical and deterministic models. The structure of statistical models is based on the patterns that appear in the extensive measured data. The structure of deterministic models is based on mechanistic principles wherever possible. Most deterministic models contain some degree of empiricism. For example, few models, if any, use turbulent-diffiision formulations that are based on first principles, but rather use measured values of dispersion. The same is true in regard... [Pg.203]

The fundamental elements of deterministic models involve a combination of chemical and meteorologic input, preprocessing with data transmission, logic that describes atmospheric processes, and concentration-field output tables or displays. In addition to deterministic models, there are statistical schemes that relate precursors (or emission) to photo-chemical-oxidant concentrations. Models may be classified according to time and space scales, depending on the purposes for which th are designed. [Pg.678]

Another aspect of matching output to user needs involves presentation of results in a statistical framework—namely, as frequency distributions of concentrations. The output of deterministic models is not directly suited to this task, because it provides a single sample point for each run. Analytic linkages can be made between observed frequency distributions and computed model results. The model output for a particular set of meteorologic conditions can be on the frequency distribution of each station for which observations are available in sufficient sample size. If the model is validated for several different points on the frequency distribution based on today s estimated emission, it can be used to fit a distribution for cases of forecast emission. The fit can be made by relating characteristics of the distribution with a specific set of model predictions. For example, the distribution could be assumed to be log-normal, with a mean and standard deviation each determined by its own function of output concentrations computed for a standardized set of meteorologic conditions. This, in turn, can be linked to some effect on people or property that is defined in terms of the predicted concentration statistics. The diagram below illustrates this process ... [Pg.698]

Figure 4.7 Graphs of two fitted deterministic models of the form y, = Po + Pi ii... Figure 4.7 Graphs of two fitted deterministic models of the form y, = Po + Pi ii...
Write two models that are deterministic (e.g., F = ma). Are there any limiting assumptions behind these deterministic models Are there any situations in which measured values would not be predicted exactly by the deterministic models ... [Pg.68]

Figure 5.1 Graph of the deterministic model = Po + Pi-tw fitted to the results of two experiments at different levels of the factor x,. Figure 5.1 Graph of the deterministic model = Po + Pi-tw fitted to the results of two experiments at different levels of the factor x,.

See other pages where Model deterministic models is mentioned: [Pg.751]    [Pg.157]    [Pg.157]    [Pg.379]    [Pg.385]    [Pg.532]    [Pg.476]    [Pg.198]    [Pg.199]    [Pg.493]    [Pg.116]    [Pg.232]    [Pg.504]    [Pg.90]    [Pg.195]    [Pg.267]    [Pg.186]    [Pg.203]    [Pg.203]    [Pg.204]    [Pg.604]    [Pg.59]    [Pg.60]    [Pg.62]    [Pg.68]   
See also in sourсe #XX -- [ Pg.38 ]




SEARCH



A common description of the deterministic and stochastic models

A deterministic model

Acceleration deterministic model

Analytical models, deterministic

Analytical models, deterministic model formulations

Complex Deterministic Models

Deterministic

Deterministic Compartmental Models

Deterministic Model Formulation

Deterministic Molecular Models

Deterministic Trajectory Models

Deterministic acoustic models, synthesis with

Deterministic and stochastic models

Deterministic global optimization modeling

Deterministic kinetic modeling

Deterministic mixed lubrication model

Deterministic model dietary exposure

Deterministic model dietary exposure estimation

Deterministic modeling

Deterministic modeling techniques

Deterministic models

Deterministic models

Deterministic models boundary conditions

Deterministic models definition

Deterministic models description

Deterministic models theorem

Deterministic synthesis models

Intonation Synthesis with Deterministic Acoustic Models

Mass action kinetic deterministic models

Mathematical model deterministic

Planning deterministic models

Simulation models, deterministic

Simulation models, deterministic model formulations

Stochastic vs. Deterministic Models

© 2024 chempedia.info