Search results for "algorithm."
showing 10 items of 4617 documents
Factors influencing the extent of inbreeding depression: an example from scots pine
1999
Detailed studies suggest that the level of inbreeding depression may vary between populations. In a study of Scots pine from Finland, the level of inbreeding depression was much lower in northern than in southern populations. We have examined theoretically whether population genetic factors, such as the level of selfing, intensity of selection against heterozygotes or homozygotes, level of mutation, a bottleneck, finite population size, or the level of polyembryony could account for this difference. Higher selfing or stronger selection against heterozygotes in the north, both at biologically reasonable levels, appear to produce changes consistent with the observed differences and we conside…
An analysis of the bias of variation operators of estimation of distribution programming
2018
Estimation of distribution programming (EDP) replaces standard GP variation operators with sampling from a learned probability model. To ensure a minimum amount of variation in a population, EDP adds random noise to the probabilities of random variables. This paper studies the bias of EDP's variation operator by performing random walks. The results indicate that the complexity of the EDP model is high since the model is overfitting the parent solutions when no additional noise is being used. Adding only a low amount of noise leads to a strong bias towards small trees. The bias gets stronger with an increased amount of noise. Our findings do not support the hypothesis that sampling drift is …
Scratch detection and removal from static images using simple statistics and genetic algorithms
2002
This paper investigates the removal of line scratches from old movies and gives a twofold contribution. First, it presents simple technique for detecting the scratches, based on an analysis of the statistics of the grey levels. Second, the scratch removal is approached as an optimisation problem, and it is solved by using a genetic algorithm. The method can be classified as a static approach, as it works independently on each single frame of the sequence. It does not require any a-priori knowledge of the absolute position of the scratch, nor an external starting population of chromosomes for the genetic algorithm. The central column of the line scratch once detected is changed with a conven…
Connections with Other Population-Based Approaches
2003
Throughout this book, we have established that scatter search (SS) belongs to the family of population-based metaheuristics. This family also includes the well-known evolutionary algorithms and the approach known as path relinking.
Diversity Management in Memetic Algorithms
2012
In Evolutionary Computing, Swarm Intelligence, and more generally, populationbased algorithms diversity plays a crucial role in the success of the optimization. Diversity is a property of a group of individuals which indicates how much these individuals are alike. Clearly, a group composed of individuals similar to each other is said to have a low diversity whilst a group of individuals dissimilar to each other is said to have a high diversity. In computer science, in the context of population-based algorithms the concept of diversity is more specific: the diversity of a population is a measure of the number of different solutions present, see [239].
A Primer on Memetic Algorithms
2012
Memetic Algorithms (MAs) are population-based metaheuristics composed of an evolutionary framework and a set of local search algorithms which are activated within the generation cycle of the external framework, see [376]. The earliest MA implementation has been given in [621] in the context of the Travelling Salesman Problem (TSP) while an early systematic definition has been presented in [615]. The concept of meme is borrowed from philosophy and is intended as the unit of cultural transmission. In other words, complex ideas can be decomposed into memes which propagate andmutate within a population.Culture, in this way, constantly undergoes evolution and tends towards progressive improvemen…
Color-assortative mating in a color-polymorphic lacertid lizard
2013
Color polymorphisms are common in lizards, which provide an excellent model system to study their evolution and adaptive function. The lacertid genus Podarcis is particularly interesting because it comprises several polymorphic species. Previous studies with lacertid lizards have tried to explain the maintenance of color polymorphisms by correlational selection between color morphs and several phenotypic traits. Particular attention has been paid to their putative role as signals reflecting alternative reproductive strategies under frequency-dependent selection, but the relationship between mating patterns and color polymorphism has not been previously considered. In this study, we use long…
3D inter-subject medical image registration by scatter search
2005
Image registration is a very active research area in computer vision, namely it is used to find a transformation between two images taken under different conditions. Point matching is an image registration approach based on searching for the right pairing of points between the two images. From this matching, the registration transformation we are searching, can be inferred by means of numerical methods. In this paper, we propose a scatter search (SS) algorithm to solve the matching problem. SS is a hybrid metaheuristic with a good trade-off between search space diversification and intensification. On the one hand, diversity is basically introduced from a population-based approach where syst…
0132: Identifying familial hypercholesterolemia from registries of patients with acute myocardial infarction: an algorithm-based approach
2016
Background and aims Familial hypercholesterolemia (FH) is at very high risk of early myocardial infarction (MI). The prevalence of FH, which is estimated to be at least 1:500 in the general population, remains unclear in patients with acute MI. From databases of 2 French regional and nationwide registries of acute MI (RICO and FAST-MI, respectively), we aimed to determine FH prevalence by developing a specific algorithm. Methods and results Consecutive patients with AMI ≤48 hours of onset included 1) in FAST-MI: during a one-month period in 213 institutions at the end of 2005 and 2) in RICO: from January 2001 December 2013 (≈13y), were considered in the 2 databases. The algorithm was adapte…
Context-dependent foraging habitat selection in a farmland raptor along an agricultural intensification gradient
2021
Abstract Gradients of agricultural intensification in agroecosystems may determine uneven resource availability for predators relying on these man-made habitats. In turn, these variations in resource availability may affect predators’ habitat selection patterns, resulting in context-dependent habitat selection. We assessed the effects of gradients of landscape composition and configuration on habitat selection of a colonial farmland bird of prey, the lesser kestrel (Falco naumanni), relying on 76 GPS-tracked nestling-rearing individuals from 10 populations scattered along an agricultural intensification gradient. Analyses were conducted considering two ecological levels of aggregation (the …