Showing papers on "Selection (genetic algorithm) published in 1999"

Goal setting and goal striving in consumer behavior.

Abstract: Goals play an essential role in the purposive behavior of consumers, but scholars only recently have begun to examine the motivation for goals, their selection and modification, and their pursuit a...

Interacting Phenotypes and the Evolutionary Process. II. Selection Resulting from Social Interactions.

Abstract: Social interactions often affect the fitness of interactants. Because of this, social selection has been described as a process distinct from other forms of natural selection. Social selection has been predicted to result in different evolutionary dynamics for interacting phenotypes, including rapid or extreme evolution and evolution of altruism. Despite the critical role that social selection plays in theories of social evolution, few studies have measured the force of social selection or the conditions under which this force changes. Here we present a model of social selection acting on interacting phenotypes that can be evaluated independently from the genetics of interacting phenotypes. Our model of social selection is analogous to covariance models of other forms of selection. We observe that an opportunity for social selection exists whenever individual fitness varies as a result of interactions with conspecifics. Social selection occurs, therefore, when variation in fitness due to interac...

Coordination games : complementarities and macroeconomics

Abstract: Introduction 1. Experimental evidence and selection 2. A framework for analysis 3. Technological complementarities 4. Imperfect competition and demand spillovers 5. Thick markets: search and matching 6. Timing of discrete choices 7. Government policy 8. Concluding thoughts References Endnotes.

The gambler's ruin problem, genetic algorithms, and the sizing of populations

Abstract: This paper presents a model to predict the convergence quality of genetic algorithms based on the size of the population. The model is based on an analogy between selection in GAs and one-dimensional random walks. Using the solution to a classic random walk problem---the gambler's ruin---the model naturally incorporates previous knowledge about the initial supply of building blocks (BBs) and correct selection of the best BB over its competitors. The result is an equation that relates the size of the population with the desired quality of the solution, as well as the problem size and difficulty. The accuracy of the model is verified with experiments using additively decomposable functions of varying difficulty. The paper demonstrates how to adjust the model to account for noise present in the fitness evaluation and for different tournament sizes.

Model Selection for Support Vector Machines

Abstract: New functionals for parameter (model) selection of Support Vector Machines are introduced based on the concepts of the span of support vectors and rescaling of the feature space. It is shown that using these functionals, one can both predict the best choice of parameters of the model and the relative quality of performance for any value of parameter.

An international look at selection practices: nation and culture as explanations for variability in practice

Abstract: A survey of 959 organizations in 20 countries was undertaken to assess whether differences in staffing practices are due in part to nation and culture. Cultural differences in uncertainty avoidance and, to a lesser extent, power distance, explained some of the national differences observed in the extensiveness of method use. Implications for understanding the best approaches to selection on a global basis are discussed.

Image matching game method and apparatus

Abstract: An image matching gaming method suitable for use as bonus game on a slot machine is provided. The method includes allowing the player to have an active role in selecting the bonus award. The player is allowed to see all the awards associated with possible selection after his choices have been made.

A practical R&D project-selection scoring tool

Abstract: An improved scoring tool for research and development (R&D) project evaluation and selection is presented that ranks project alternatives based on the criteria of relevance, risk, reasonableness, and return. The scoring algorithm explicitly incorporates tradeoffs among the evaluation criteria and calculates a relative measure of project value by taking into account the fact that value is a function of both merit and cost. Implementation of the selection method in a federal research laboratory is discussed. A comprehensive overview of the R&D project selection literature is included.

The importance of genetic diversity in livestock populations of the future.

Abstract: Farm animal genetic diversity is required to meet current production needs in various environments, to allow sustained genetic improvement, and to facilitate rapid adaptation to changing breeding objectives. Production efficiency in pastoral species is closely tied to the use of diverse genetic types, but greater genetic uniformity has evolved in intensively raised species. In poultry, breeding decisions are directed by a few multinational companies and involve intense selection, the use of distinct production lines, and very large populations. In dairy cattle, the Holstein breed dominates production. Intensive sire selection is leading to relatively rapid inbreeding rates and raises questions about long-term effects of genetic drift. Key questions in management of farm animal genetic diversity involve the distribution of potentially useful quantitative trait locus alleles among global livestock breeds. Experiments with tomato, maize, and mice suggest that favorable alleles can exist in otherwise lowly productive stocks; this cryptic variation may potentially contribute to future selection response. Genetic improvement under relatively intense unidirectional selection may involve both increases in the frequency of favorable additive alleles as well as the progressive breakdown of homeostatic regulatory mechanisms established under the stabilizing selection that is characteristic of natural populations. Recombination among closely linked regulatory loci and new, potentially favorable mutations are possible sources of long-term genetic variation. A greater understanding of the potential that these alternative mechanisms have for supporting long-term genetic improvement and of genetic relationships among global livestock populations are priorities for managing farm animal genetic diversity.

Positive selection on the H3 hemagglutinin gene of human influenza virus A.

Abstract: The hemagglutinin (HA) gene of influenza viruses encodes the major surface antigen against which neutralizing antibodies are produced during infection or vaccination. We examined temporal variation in the HA1 domain of HA genes of human influenza A (H3N2) viruses in order to identify positively selected codons. Positive selection is defined for our purposes as a significant excess of nonsilent over silent nucleotide substitutions. If past mutations at positively selected codons conferred a selective advantage on the virus, then additional changes at these positions may predict which emerging strains will predominate and cause epidemics. We previously reported that a 38% excess of mutations occurred on the tip or terminal branches of the phylogenetic tree of 254 HA genes of influenza A (H3N2) viruses. Possible explanations for this excess include processes other than viral evolution during replication in human hosts. Of particular concern are mutations that occur during adaptation of viruses for growth in embryonated chicken eggs in the laboratory. Because the present study includes 357 HA sequences (a 40% increase), we were able to separately analyze those mutations assigned to internal branches. This allowed us to determine whether mutations on terminal and internal branches exhibit different patterns of selection at the level of individual codons. Additional improvements over our previous analysis include correction for a skew in the distribution of amino acid replacements across codons and analysis of a population of phylogenetic trees rather than a single tree. The latter improvement allowed us to ascertain whether minor variation in tree structure had a significant effect on our estimate of the codons under positive selection. This method also estimates that 75.6% of the nonsilent mutations are deleterious and have been removed by selection prior to sampling. Using the larger data set and the modified methods, we confirmed a large (40%) excess of changes on the terminal branches. We also found an excess of changes on branches leading to egg-grown isolates. Furthermore, 9 of the 18 amino acid codons, identified as being under positive selection to change when we used only mutations assigned to internal branches, were not under positive selection on the terminal branches. Thus, although there is overlap between the selected codons on terminal and internal branches, the codons under positive selection on the terminal branches differ from those on the internal branches. We also observed that there is an excess of positively selected codons associated with the receptor-binding site and with the antibody-combining sites. This association may explain why the positively selected codons are restricted in their distribution along the sequence. Our results suggest that future studies of positive selection should focus on changes assigned to the internal branches, as certain of these changes may have predictive value for identifying future successful epidemic variants.

Estimating the genetic architecture of quantitative traits.

Abstract: Understanding and estimating the structure and parameters associated with the genetic architecture of quantitative traits is a major research focus in quantitative genetics. With the availability of a well-saturated genetic map of molecular markers, it is possible to identify a major part of the structure of the genetic architecture of quantitative traits and to estimate the associated parameters. Multiple interval mapping, which was recently proposed for simultaneously mapping multiple quantitative trait loci (QTL), is well suited to the identification and estimation of the genetic architecture parameters, including the number, genomic positions, effects and interactions of significant QTL and their contribution to the genetic variance. With multiple traits and multiple environments involved in a QTL mapping experiment, pleiotropic effects and QTL by environment interactions can also be estimated. We review the method and discuss issues associated with multiple interval mapping, such as likelihood analysis, model selection, stopping rules and parameter estimation. The potential power and advantages of the method for mapping multiple QTL and estimating the genetic architecture are discussed. We also point out potential problems and difficulties in resolving the details of the genetic architecture as well as other areas that require further investigation. One application of the analysis is to improve genome-wide marker-assisted selection, particularly when the information about epistasis is used for selection with mating.

Bonus games for gaming machines with strategy options

Abstract: A gaming machine bonus feature involving the selection of strategy options The player selects strategy options, one at a time, in successive game stages Each of the strategy options is associated with a game activity having a number of possible outcomes After selection of the strategy options, a gaming machine processor determines the outcomes associated with the designated game activity In one embodiment, the game program defines a selection probability for the possible outcomes which may vary in the successive game stages In accordance with another aspect of the present invention, there is provided a gaming machine and method of operating of the gaming machine to execute a game program defining a first and second strategy option Each of the first and second strategy options are associated with a designated game activity The method comprises a first step of selecting, under player control, one of the first and second strategy options The processor identifies the designated game activity associated with the selected strategy option and a number of possible outcomes of the designated game activity Then, the processor selects one of the possible outcomes and the gaming machine displays indicia of the selected outcome

A parameter-less genetic algorithm

Abstract: From the user's point of view, setting the parameters of a genetic algorithm (GA) is far from a trivial task. Moreover, the user is typically not interested in population sizes, crossover probabilities, selection rates, and other GA technicalities. He is just interested in solving a problem, and what he would really like to do, is to hand-in the problem to a blackbox algorithm, and simply press a start button. This paper explores the development of a GA that fulfills this requirement. It has no parameters whatsoever. The development of the algorithm takes into account several aspects of the theory of GAs, including previous research work on population sizing, the schema theorem, building block mixing, and genetic drift.

Cover as a habitat element for temperate ungulates: effects on habitat selection and demography

Abstract: may affect important aspects of ungulate biology such as grouping tendencies (Hirth 1977, Lagory 1986), vigilance behavior (Goldsmith 1990), alarm and flight responses (Lagory 1987), and circadian activity rhythms (Andersen 1989). Cover includes, by definition, anything which veils or conceals, shelters or protects (Webster 1978), and can be both vegetation and topography (Dasmann 1971). Some authors have stated that cover characteristics

A cautiously optimistic vision for marker-assisted breeding.

Abstract: Even though marker-assisted selection now plays a prominent role in the field of plant breeding, examples of successful, practical outcomes are rare. It is clear that DNA markers hold great promise, but realizing that promise remains elusive. Despite innovations like better marker systems and improved genetic mapping strategies, most marker associations are not sufficiently robust for successful marker-assisted selection. In large part this is due to inadequate experimental design. Molecular breeders must reassess their research programs so that DNA marker work leads to useful selection tools and valuable germplasm. As molecular breeders adopt more rigorous experimental guidelines and ambitious goals, they also need to integrate the growing body of knowledge from genomics and bioinformatics.

Comparison of selection strategies for marker-assisted backcrossing of a gene

Abstract: Marker-assisted selection can accelerate recovery of the recurrent parent genome (RPG) in backcross breeding. In this study, computer simulations were used to compare selection strategies with regard to (i) the proportion of the RPG recovered and (ii) the number of marker data points (MDP) required in a backcross programme designed for introgression of one target allele from a donor line into a recipient line. Simulations were performed using a published maize (Zea mays) genetic map consisting of 80 markers. Selection for the target allele was based on phenotypic evaluation. In comparison with a constant population size across all generations, increasing population sizes from generation BC1 to BC3 reduced the number of required MDP by as much as 50% without affecting the proportion of the RPG. A four-stage selection approach, emphasizing in the first generations selection for recombinants on the carrier chromosome of the target allele, reduced the required number of MDP by as much as 75% in comparison to a selection index taking into account all markers across the genome. Adopting the above principles for the design of marker-assisted backcross programmes resulted in substantial savings in the number of MDP required.

Selection Improves Drought Tolerance in Tropical Maize Populations: II. Direct and Correlated Responses among Secondary Traits

Abstract: Recurrent selection for drought tolerance for three to eight cycles has increased grain yield (GY) under drought at flowering by 30 to 50% in three lowland tropical maize (Zea mays L.) populations. The relationships among secondary traits as a result of this selection have not been determined, however. The objectives of this study were to measure direct and correlated changes due to selection in secondary traits by evaluating cycles of selection and appropriate check entries at five water-stressed (mean yield 2.35, range 1.01-4.48 Mg ha) and five well-watered environments (mean yield 7.96, range 5.81-10.40 Mg ha). Under drought, changes per cycle with recurrent S selection (P < 0.05) were as follows: GY 12.6%, fertile ears per plant (EPP) 8.9%, grains per fertile ear (GPE) 6.3%, grain number per square meter 12.2%, 1000 grain weight no change, anthesis-silking interval (ASI) -22.0%, days from sowing to 50% anthesis -0.7%, plant height -2.0%, primary tassel branch number -5.9%, and senesced leaf area 2.7%. Responses under well-watered conditions were smaller but generally of the same sign. Grain yield was strongly associated with grain number per square meter in both water-stressed and well-watered environments (r = 0. 96; r = 0.87; P < 0.001). Grain yield, EPP, and GPE were strongly correlated with ASI across entries under drought (r = -0.89, -0.93, -0.90; P < 0.001), though not when water was plentiful. The use of managed stress environments that consistently reveal genetic variation for these traits at specific times during crop development is endorsed for selection purposes.

The application of discrete choice models to wildlife resource selection studies

Abstract: This paper introduces the theory and application of discrete choice models to resource selection studies. Discrete choice models calculate the probability of an individual selecting a resource as a function of the attributes of that resource and all other available resources. The data for these attributes may be continuous or categorical. When availability is the same for all individuals and only two resources are available, the multinomial logit discrete choice model reduces to the logistic model. Discrete choice models and advances in GIS technology give the researcher flexibility in defining resource availability separately for each individual over time and space. The output of the discrete choice approach also provides managers with a tool to explore the effects of potential management actions and provides researchers with new hypotheses deserving of further investigation. To illustrate the application of discrete choice models to resource selection studies, we present a case study of summer diurnal bed site selection by elk (Cervus elaphus) in Custer State Park, South Dakota, United States. The results demonstrate the importance of factors relating to thermal regulation, hiding cover, and potentially forage, in elk bed site selection in this region.

Why biodiversity surveys are good value

Abstract: Article 8 of the Convention on Biological Diversity obliges contracting parties to establish protected areas for conservation. This can be achieved in smaller networks of reserves if their design is based on how well different sites complement one another biologically, rather than on more commonly used criteria, such as species richness or simple availability for acquisition1,2. However, this increase in efficiency3 requires species lists for each candidate site, and obtaining such data can be expensive; for example, a detailed survey of five taxa across 15,000 km2 of forest in Uganda took nearly 100 person-years and cost about US$1 million4,5. Here we ask whether investing in such surveys makes economic sense, or whether conservation agencies would be better advised to continue following more traditional reserve selection procedures, at the cost of having to conserve larger reserve networks.

Switched parasitic elements for antenna diversity

Abstract: Switched parasitic elements provide a useful implementation of antenna pattern diversity. The basic principle is presented with some examples of wire antennas computed using the method of moments. The modeled diversity gain available from selection combining of uncorrelated signals is used to quantify the expected improvement relative to nondiversity antennas. The advantage of the switched parasitic concept is that it is a relatively simple system, which can give the adaptive antenna performance of many branch selection or switched diversity.

Another set of responses and correlated responses to selection on age at reproduction in Drosophila melanogaster.

Abstract: Ageing is the decline in survival probability and fertility later in adult life. It can evolve through mutation accumulation and pleiotropy. Artificial selection by age at reproduction is a useful method for detecting the effects of pleiotropy, and for producing lines that differ in their rate of ageing for further analysis. However, the approach has encountered difficulties from gene-environment interaction and inadvertent selection. We have produced a new set of selection lines in Drosophila melanogaster, breeding from either 'young' or 'old' adults, and avoiding some of the difficulties present in previous studies. Breeding from older adults resulted in an evolutionary increase in survival but, contrary to all previous studies using this method, in no increase in late-life fertility. The increase in survival was accompanied by an evolutionary decline in fertility early in adult life, confirming the importance of pleiotropy in the evolution of ageing. Contrary to previous studies, there were no correlated responses to selection in the pre-adult period; development time, larval competitive ability and adult size achieved did not differ between the lines from the two selection regimes.

Forming teams: an analytical approach

Abstract: The selection of multi-functional teams is a key issue in problem solving. Currently there are no papers in the literature that discuss analytical approaches to forming teams. Furthermore, no comprehensive model exists to prioritize team membership based on customer requirements or product characteristics. To deal with the underlying complexities of the team selection process, a methodology for team formation is developed. The methodology is based on the Analytical Hierarchy Process (AHP) approach and the Quality Function Deployment (QFD) method. A QFD planning matrix is used to organize the factors considered in the team selection. The importance measure for each team member is determined with the AHP approach. A mathematical programming model is developed to determine the composition of a team. The methodology developed in this paper is tested by the selection of teams in concurrent engineering. A detailed discussion of the model implementation and hov/ to reduce the number of comparisons in the AHP pro...

Natural selection on thermogenic capacity of high-altitude deer mice.

Abstract: Adaptive explanations that rely on physiological arguments are common, but tests of hypotheses about the significance of whole-animal physiological performance (e.g., aerobic capacities) are rare. We studied phenotypic selection on the thermogenic capacity (i.e., maximal rate of oxygen consumption [VO2 max] elicited via cold exposure) of high-altitude (~3800 m) deer mice (Peromyscus maniculatus). A high VO2 max equates to a high capacity for heat production and should favor survival in the cold environments prevalent at high altitude. Strong directional selection favored high VO2 max, at least in one year. The selection for increased VO2 max is consistent with predictions derived from incorporating our physiological data into a biophysical model. During another year, we found weak evidence of selection for decreased body mass. Nonlinear selection was not significant for any of the selection episodes we studied. The strong directional selection for VO2 max that we observed suggests that-given ample genetic variation-aerobic metabolism and perhaps endothermy may have evolved rapidly on the geological time scale.

The coffee-machine system: how international selection really works

Abstract: The literature on expatriate selection tends to present lists of criteria, with the implicit assumption that the process is formal and rational. The limited empirical work there is in this area suggests that these criteria have little impact on selection in practice. This paper argues that a deeper understanding of selection systems is needed and presents research showing the outcomes of different kinds of systems, suggesting that closed, informal systems predominate and outlining the practical and research implications of such systems.

Critical issues affecting an ERP implementation : Entreprise computing

Abstract: Implementing an ERP causes massive change that needs to be carefully managed to reap the benefits of an ERP solution. Critical issues that must be carefully considered to ensure successful implementation include commitment from top management, reengineering of the existing processes, integration of the ERP with other business information systems, selection and management of consultants and employees, and training of employees on the new system.

Subset selection for improved parameter estimation in on-line identification of a synchronous generator

Abstract: This paper examines subset selection for nonlinear least squares parameter estimation, and applies the methodology to a test system previously studied in the power system literature, involving the on-line identification of a synchronous generator model with many parameters. Subset selection partitions the parameters into well-conditioned and ill-conditioned subsets. We show for the test system that fixing the ill-conditioned parameters to prior estimates (even if these prior estimates are substantially in error), and estimating only the remaining parameters, significantly improves the performance of the estimation algorithm and greatly enhances the quality of the estimated parameters. It is shown that attempts to estimate all of the model parameters, as done in the original work with this test system, can yield extremely unreliable results.