Brute force approach

It can be said that these three main strategies have been applied equally and very often in combination. Basically, the first approach implies the use of a faster computer or a parallel architecture. To some extent it sounds like a brute force approach but the exponential increase of the computer power observed since 1970 has made the hardware solution one of the most popular approaches. The Chemical Abstracts Service (CAS) [10] was among first to use the hardware solution by distributing the CAS database onto several machines. 

Reducing infiltration. Traditional brute force approaches to weather stripping were redesigned to reduce infiltration with less material that contacted a larger surface area. New materials such as thermoplastic elastomers offered additional potential to control for infiltration. But perhaps the most important way to control infiltration is proper installation. 

What strategy should one follow In the classical experiment, one factor is varied at a time, usually over several levels, and a functional relationship between experimental response and factor level is established. The data analysis is carried out after the experiment(s). If several factors are at work, this approach is successful only if they are more or less independent, that is, do not strongly interact. The number of experiments can be sharply increased as in the brute-force approach, but this might be prohibitively expensive if a single production-scale experiment costs five- or six-digit dollar sums. Figure 3.4 explains the problem for the two-factor case. 

Figure 3.4. Optimization approaches. The classical approach fixes all factors except one, which is systematically varied (rows of points in left panel) the real optimum (x) might never be found this way. The brute-force approach would prescribe experiments at all grid points (dotted lines), and then further ones on a finer grid centered on 80/1 2, for example.

As described in Sect. 1, the relevant length scales and time scales are a serious problem for any simulation of polymer melts [12,16-20] and, as discussed, a polymer coil has structures on different distance scales (Fig. 1.2) [17] and relaxations on different time scales. A brute force approach, consisting of a simulation of fully atomistic models of a sufficiently large system over time scales for which thermal equilibration could be reached at practically relevant temperatures, is totally impossible. Useful progress requires a different approach. 

Any approach different from this brute force approach must make compromises, as far as the complete realistic modelling of polymeric materials with all their details is concerned. Different groups tend to make rather different compromises, depending on what features of the problem they consider particularly important. Here we discuss only one approach proposed [28,30, 32,175,176] by the condensed matter theory group at the University of Mainz. This approach follows a rather radical concept, since all fast vibrational motions are completely eliminated, and in addition a description of the local... 

There are two possible solutions to this problem. We may either modify our ansatz for the wavefunction, including terms that depend explicitly on the interelectronic coordinates [26-30], or we may take advantage of the smooth convergence of the correlation-consistent basis sets to extrapolate to the basis-set limit [6, 31-39], In our work, we have considered both approaches as we shall see, they are fully consistent with each other and with the available experimental data. With these techniques, the accurate calculation of AEs is achieved at a much lower cost than with the brute-force approach described in the present section. 

At the other extreme in terms of system size and accuracy stand brute-force approaches such as those based on wavefunctions with explicit interelectronic distances. 

If we wanted to generate the representation matrices of 4, we would find the three elementary transpositions and the identity and then generate the other 20 matrices. On the other hand, we could find the representations of the group S2 in 54. This consists of two matrices, U[ E)] and C/[(12)]. We could then use C/[(23)] and f/[(13)] to generate all of the six elements in S3. We could then use C/[(34)j, f/[(14)], and f/[(24)] to generate the rest of 54. While this may seem at first more time-consuming, it is much more easily automated than the brute force approach. 

No claim for accuracy can be made for brute-force approaches of this sort. It remains, however, that a most instructive link is created in this manner between typical saturated, olefinic, acetylenic, and aromatic hydrocarbons. This is rewarding all the pieces seem to fall in place in a very orderly fashion. 

Besides the use of large volume samples, there are also other "brute force" approaches frequently used since the earlier reports of solid-state Mg NMR, including isotopic enrichment and the use of malefic fields as strong as possible.. 39.42,, 45-52 jg doubt that the increase in the... 

These partial derivatives provide a lot of information (ref. 10). They show how parameter perturbations (e.g., uncertainties in parameter values) affect the solution. Identifying the unimportant parameters the analysis may help to simplify the model. Sensitivities are also needed by efficient parameter estimation procedures of the Gauss - Newton type. Since the solution y(t,p) is rarely available in analytic form, calculation of the coefficients Sj(t,p) is not easy. The simplest method is to perturb the parameter pj, solve the differential equation with the modified parameter set and estimate the partial derivatives by divided differences. This "brute force" approach is not only time consuming (i.e., one has to solve np+1 sets of ny differential equations), but may be rather unreliable due to the roundoff errors. A much better approach is solving the sensitivity equations... 

One may follow the brute-force approach of enumerating fully all possible combinations of 0 - 1 variables for the elements of the y vector. Unfortunately, such an approach grows exponentially in time with respect to its computational effort. For instance, if we consider one hundred 0 - 1 y variables then we would have 2100 possible combinations. 

If the number and type of gaseous species to be detected can be narrowly defined and if they remain invariable, it is possible to use a brute-force approach and to construct a chemical sensor without detailed knowledge of the mechanism of its operation. In such a case, the output of the sensor - be it voltage, current, or any other physical... 

In such cases, one can retreat to the brute force approach of developing a separate calibration for each analyzer. However, for empirical multivariate calibrations, which require a large number of calibration samples each, this approach can become very laborious. Furthermore, if there is a significant cost associated with the collection, preparation, and analysis of calibration standards, the cost of this instrument-specific calibration approach can become prohibitive. 

There are the usual boundary conditions depending on the experiment performed on this system. One possible way to handle all this is simply to write out the whole system as a large linear system, expand that to include the boundary conditions, and solve. This, brute force approach (see below), has in fact been used [138] and can even be reasonably efficient if the number of equations is kept low, by use, for example, of imequal intervals, described in Chap. 7. If the equations in such a system are arranged in the order as above (6.55), it will be found that it is tightly banded, except for the first two rows for the boundary conditions, which may have a number of entries up to the number n used for the current approximation. 

The power of the screening or selection method ultimately delineates the extent to which the sequence space can be explored. Screening usually involves the physical separation of mutants identified on some phenotypic change such as colony size or color. It is essentially a brute force approach that is amenable to amplification by robotics and is limited to identification of mutants in a population of transfected bacteria or cells totaling at most one million and more with typically only a few thousand clones each harboring a different mutant gene. Selection takes advantage... 

The brute-force approach involves the following steps ... 

A classic success case of the brute-force approach is the discovery of Prontosil rubrum , the first sulfonamide type... 

Much is being done to increase the catalytic activity of metals. Certain binary alloys seem to have higher catalytic activity than either of their components separately. Oxides and oxide mixtures have been tried, and electrodes modified by organic or metal-organic molecules hold hope for better catalytic properties. An engineering approach, that has been quite successful (although some may consider it a "brute force" approach) is to increase the roughness of the surface, thus... 

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