Big Chemical Encyclopedia

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

Articles Figures Tables About

Uncertainty final interval

From (1.26), it is possible either to evaluate a priori the interval of uncertainty after a predetermined amount n of iterations or, given the final interval, to know a priori the number of iterations required to reach it. [Pg.7]

Given the maximum number N of function evaluations, the goal is to minimize the final interval of uncertainty Lp or its reduction ratio a ... [Pg.45]

If neither the number of function evaluations nor the final interval of uncertainty is given, the evaluations can be stopped when the solution is satisfactory - for example when the function is smaller than a specific value. In this case, it is necessary to set up the method to ensure it is efficient independent of the amount of function evaluations. [Pg.46]

Thus far, we have denoted the final interval of uncertainty with Lp even though it would be more correct to denote the maximum final interval of uncertainty by the same symbol. [Pg.46]

The final interval of uncertainty depends on the function. Conversely, the maximum final interval of uncertainty does not change, given the points at which the function is to be evaluated actually, this is the worst final interval achievable by applying the predefined strategy. [Pg.46]

Consider the problem of defining the optimal strategy to minimize the maximum final interval of uncertainty, given the initial interval of uncertainty, and the number of function evaluations. [Pg.46]

This problem can also be investigated in its complementary form given the initial and final ranges of uncertainty, the goal is to find the strategy that minimizes the total amount of function evaluations required to obtain a maximum final interval of uncertainty smaller than the assigned one. [Pg.46]

When only two points are available, their optimal position is easy to find. The two points should be evenly spaced by the center, otherwise the maximum final interval of uncertainty cannot be minimized. Moreover, they should be placed at the minimum acceptable distance d since the closer they are to each other, the smaller the final interval. [Pg.48]

Our problem can now be solved by starting not at the beginning but at the end at the end of the search, after N — 1 function evaluations, the interval of uncertainty is In i and the last function evaluation needs to be positioned. One of the previous points - the identity of which is unknown to us - is already within the interval of uncertainty. To minimize the maximum final interval of uncertainty, Ln, obtained by introducing the last point, t, the last two points should be symmetric with respect to the center of the interval Ln-i and at the minimum distance d (Figure 2.2). [Pg.48]

The final interval of uncertainty In must be larger than or equal to 2 5, otherwise... [Pg.51]

It minimizes the maximum final interval of uncertainty for any function. [Pg.53]

Unfortunately, some of these advantages may also turn out be disadvantages at times too. The Fibonacci method minimizes the maximum final interval of uncertainty only if the required function evaluations are accomplished. [Pg.53]

It is also possible to modify the Fibonacci method to obtain a series that minimizes the maximum final interval of uncertainty when a point is already positioned in the starting interval. In this case, the final interval is not univocally determined by the number of points, but different widths can be obtained depending on the position of the first point and the function to be minimized. [Pg.54]

II. 12-6.88 = 4.24 far from t. Whatever the best point, the final interval of uncertainty after four points is 4.24, vhereas the Fibonacci method yields a final range equal to 4 (or less with a value of d < 1). Nevertheless, if the search is stopped at the third point, the interval of uncertainty is 6.88 for the golden section and 7 for the Fibonacci method, which is only optimized for four points and a value of d = 1. [Pg.55]

OPPTS 860.1500, p. 16, indicates that 3-5 sampling points should be included in the decline trials. For applications close to the normal harvest time, the RAC may be harvested at selected intervals between the time of final application and a normal harvest or slightly delayed harvest. If the application is made long before the normal harvest, then representative plant tissues (including immature RAC) may need to be harvested in order to stretch the harvest period. A single composite sample is all that is required from each selected time point, but two or more samples may be harvested to reduce uncertainty about the actual amount of residue present at each sample time interval. These decline samples should be collected and treated the same as normal RAC samples. The samples should be frozen as soon as possible after collection. The instructions for decline sample collection and handling described in the protocol should be followed closely. [Pg.158]

It is important to remember that sometimes, in spite of the excellent performances of an AMS measurement, the final uncertainty on the true calendar age of a sample is a function of the behaviour of the calibration curve in that time interval a small error on the radiocarbon age does not necessarily correspond to a small, or a unique, calendar span on the BC/AD axis. [Pg.479]

Multidimensional Data Intercomparisons. Estimation of reliable uncertainty intervals becomes quite complex for non-linear operations and for some of the more sophisticated multidimensional models. For this reason, "chemometric" validation, using common, carefully-constructed test data sets, is of increasing importance. Data evaluation intercomparison exercises are thus analogous to Standard Reference Material (SRM) laboratory intercomparisons, except that the final, data evaluation step of the chemical measurement process is being tested. [Pg.70]

Several simulations have been carried out under process parameter uncertainties e.g. in pre-exponential rate constant (ko) and activation energy (Ea). In all case studies we considered 10 time intervals when reactor temperature and switching time are optimized while minimizing the final batch operation time. Results, reported in the value of minimum batch time to obtain the desired product C and the amount of the desired product C at the end of batch operation, from on-line dynamic optimization strategy are also compared with those from the off-line strategy. [Pg.111]

Is there a need to show the uncertainty or confidence interval of the final result of all extrapolations, and/or of each extrapolation step ... [Pg.319]

All contributions and final values of the Lamb shifts in the lowest states of hydrog-like ions 4He+, 14N6+ and 15N6+ are presented in Tables 5, 6 and 7, respectively. The final results for intervals which can be measured are listed in Table 8. The results in Table 8 involve three main sources of uncertainty and we split the uncertainty there and in auxiliary Tables 5—7, respectively ... [Pg.647]

As has already been pointed out, two different methods of calibration have been used in the work so far reported. One can measure in terms of H/3, and in this way determine the ground state Lamb shift. If instead one uses a frequency standard, one can determine the IS Lamb shift by allowing for the other contributions to the measured IS - 2S interval this requires a value of the Rydberg constant from another source. Alternatively, if one assumes the IS Lamb shift known from theory at the level of accuracy of the experiment, one can regard the measurement as a determination of the Rydberg constant. All the most recent work has been in terms of the external standards provided by the tellurium transitions, but these introduce an uncertainty which in the case of the cw experiments dominates the final error. This situation must be... [Pg.879]


See other pages where Uncertainty final interval is mentioned: [Pg.285]    [Pg.2548]    [Pg.46]    [Pg.433]    [Pg.449]    [Pg.109]    [Pg.42]    [Pg.27]    [Pg.44]    [Pg.16]    [Pg.119]    [Pg.122]    [Pg.160]    [Pg.13]    [Pg.53]    [Pg.57]    [Pg.184]    [Pg.48]    [Pg.116]    [Pg.324]    [Pg.420]    [Pg.745]    [Pg.285]    [Pg.116]    [Pg.324]    [Pg.647]    [Pg.2764]   
See also in sourсe #XX -- [ Pg.46 ]




SEARCH



Uncertainty interval

© 2024 chempedia.info