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Population size

The fitness of the best string in an attempt to solve the dipoles problem using a population of [Pg.148]

The success of the algorithm relies on the GA processing many generations solutions can only evolve if evolution is possible. Excessively large populations are especially problematic if evaluation of the fitness function is computationally expensive as it is, for example, in the chemical flowshop problem (section 5.10) in which evaluating the total time required for all chemicals to be processed by the flowshop in a defined order may take far more time than the execution of all other parts of the GA combined. [Pg.149]


Process structures with appropriate quantum or molecular mechanical technique to compute desired properties eg, relative energies, dipole moment, conformer populations, size, shape, etc. [Pg.158]

The impact of chemical pollution on the reproductive success and population sizes of wildlife species is often difficult to assess. In many cases, environmental factors such as habitat restriction, stress due to human intrusion and changes in natural food supplies owing to hunting, fishing and restocking policies may have a significant, even predominant, effect on population size. This makes it difficult to determine to what extent, if any, environmental endocrine disrupters may be contributing to observed effects on reproduction or population size in wildlife species. [Pg.9]

Anthropological research with modern hunter-gatherers suggests an ideal type or model for this kind of society. They were nomadic and exhibited low population size and density—on the order of thirty people per thousand square miles. Paramount in maiiitaining this low size and density was an imperative common to all hunter-gatherer women. A nomad woman had to move herself, all that her family owned (which was very little), and her children at a moments notice. Modern hunters and gatherers often have to walk twenty miles a day, so mothers cannot carry more than one small child. Faced with this restriction, women are careful to space their children so that the two or rarely three children they have... [Pg.72]

The population size of a particular species that can be supported in any given ecosystem depends on the resource needs—ultimately, the energy needs—of that species. [Pg.180]

To include a linear decreasing function of the population size, the second-order cell population inhibition is considered ... [Pg.53]

These may be primary or secondary. Please indicate the minimum important differences, c.f. justification of population size. Please outline methods and timing for assessing, recording, and analysing of efficacy parameters. [Pg.84]

Initially, it was assumed that the HlV-1 population is infinite, evolution is deterministic, and antiretroviral resistance development is definite (Coffin 1995). However, our research amongst others has demonstrated that the effective population size, defined as the average number of HIV variants that produces infectious progeny is relatively small (Leigh Brown 1997 Leigh Brown and Richman 1997 Nijhnis et al. 1998). This can be explained because the majority of virus particles that are produced harbor deleterious mutations resulting in noninfectious virus. Also limited target cell availability and inactivation of potentially infectious viruses by the host... [Pg.301]

Note. If the N dimensions yield very different numerical values, such as 105 3 mmol/L, 0.0034 0.02 meter, and 13200 600 pg/ml, the Euclidian distances are dominated by the contributions due to those dimensions for which the differences A-B, AS, or BS are numerically large. In such cases it is recommended that the individual results are first normalized, i.e., x = (x - Xn,ean)/ 5 t, where Xmean and Sx are the mean and standard deviation over all objects for that particular dimension X, by using option (Transform)/(Normalize) in program DATA. Use option (Transpose) to exchange columns and rows beforehand and afterwards The case presented in sample file SIEVEl.dat is different the individual results are wt-% material in a given size class, so that the physical dimension is the same for all rows. Since the question asked is are there differences in size distribution , normalization as suggested above would distort tbe information and statistics-of-small-numbers artifacts in the poorly populated size classes would become overemphasized. [Pg.371]

FIGURE 5.7 Peregrine population size in Britain (1930-1939 = 100) showing the 1961 population decline and subsequent recovery, together with an outline of pesticide usage (from Ratcliffe 1993). [Pg.125]

Traffic Population Size Sample Size Lead Level ( g/dl) ... [Pg.60]

Daily, G.C., Ehrlich, A.H., and Ehrlich, P.R., 1994, "Optimum Human Population Size," Population and Environment, A Journal of Interdisciplinary Studies 15 469. [Pg.90]

The speed with which adaptations appear, such as, for example, resistance to pesticides, depends on the pressure of selection. When using pesticides, the pressure is practically 100% and, therefore, new characteristics appear very rapidly, in just 2-3 generations. The speed with which resistance appears depends also on the population size of the target species the larger the population, the more probable that resistance will appear in some members of the first generation. The populations of target species are always large otherwise there would be no reason to try to suppress them. Therefore, in each suppressed population, there will inevitably be more resistant individuals. [Pg.118]

Microbial Biotransformation. Microbial population growth and substrate utilization can be described via Monod s (35) analogy with Michaelis-Menten enzyme kinetics (36). The growth of a microbial population in an unlimiting environment is described by dN/dt = u N, where u is called the "specific growth rate and N is microbial biomass or population size. The Monod equation modifies this by recognizing that consumption of resources in a finite environment must at some point curtail the rate of increase (dN/dt) of the population ... [Pg.30]

This formulation is similar to the "second-order" equations used to describe the kinetics of chemical reactions, and u(max)/(Y Ks) can by analogy be termed a second-order biolysis rate constant Kb2, with units /time/(cells/liter) when population sizes N are expressed in cells/liter. [Pg.32]

The magnitude of exposure in a geographic area is a function not only of the amount of pollutant to which a "typical" individual is exposed but also of the size of the population exposed. This is especially important in the calculation of risk for an area or subpopulation. The resulting quantity is a population exposure factor which is the product of the individual pollutant intake level per unit time (average or maximum) multiplied by the population size exposed. [Pg.293]

The progress of the GA depends on the values of several parameters that must be set by the user these include the population size, the mutation rate, and the crossover rate. Choosing the values of these parameters is not the only decision to be made at the start of a run, however. There are tactical decisions to be made about the type of selection method, the type of crossover operator, and the possible use of other techniques to make the algorithm as effective as possible. The choice of values for these parameters and type of crossover or selection can make the difference between a calculation that is no better (or worse) than a conventional calculation and one that is successful. In this section, we consider how to choose parameters to run a successful GA and start with a look at tactics. [Pg.135]

In constructing a GP program, it is necessary not only to define GA-like parameters, such as the population size, the type of crossover, and the number of generations, but also parameters that relate specifically to the components of the candidate programs that the GP will build. These include ... [Pg.164]

A standard GA is used in the experiments and the whole set of experiments was done on-computer (i.e., the actual programmable chip was not used during evolution). The GA parameters follow. Population size is three hundred selection method is fitness proportional with elitism crossover probability equals 0.8 (then 0 in successful runs) mutation probability is 0.1 the maximum number of generations was set to one hundred fifty. [Pg.298]

For the fitness trials, the population size is two hundred initMult is twenty the probability of crossover is 0.8 the rate of elitism is 0.01 the probability of copy mutation is 0.05 the probability of power mutation is 0.05 useSeed is set to true 9 is one hundred. [Pg.306]


See other pages where Population size is mentioned: [Pg.527]    [Pg.54]    [Pg.277]    [Pg.279]    [Pg.73]    [Pg.73]    [Pg.74]    [Pg.302]    [Pg.303]    [Pg.304]    [Pg.305]    [Pg.75]    [Pg.138]    [Pg.18]    [Pg.11]    [Pg.54]    [Pg.123]    [Pg.116]    [Pg.249]    [Pg.675]    [Pg.32]    [Pg.190]    [Pg.120]    [Pg.120]    [Pg.148]    [Pg.304]    [Pg.319]    [Pg.4]    [Pg.65]   
See also in sourсe #XX -- [ Pg.17 , Pg.30 ]

See also in sourсe #XX -- [ Pg.355 ]

See also in sourсe #XX -- [ Pg.12 , Pg.22 ]




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