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Registros recuperados: 9
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A genetic algorithm for the ligand-protein docking problem Genet. Mol. Biol.
Magalhães,Camila S. de; Barbosa,Hélio J.C.; Dardenne,Laurent E..
We analyzed the performance of a real coded "steady-state" genetic algorithm (SSGA) using a grid-based methodology in docking five HIV-1 protease-ligand complexes having known three-dimensional structures. All ligands tested are highly flexible, having more than 10 conformational degrees of freedom. The SSGA was tested for the rigid and flexible ligand docking cases. The implemented genetic algorithm was able to dock successfully rigid and flexible ligand molecules, but with a decreasing performance when the number of ligand conformational degrees of freedom increased. The docked lowest-energy structures have root mean square deviation (RMSD) with respect to the corresponding experimental crystallographic structure ranging from 0.037 Å to 0.090 Å in the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Ligand-protein docking; Flexible docking; Genetic algorithms.
Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572004000400022
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Artificial intelligence in seeding density optimization and yield simulation for oat AGRIAMBI
Dornelles,Eldair F.; Kraisig,Adriana R.; Silva,José A. G. da; Sawicki,Sandro; Roos-Frantz,Fabricia; Carbonera,Roberto.
ABSTRACT Artificial intelligence may represent an efficient strategy for simulation and optimization of important processes in agriculture. The main goal of the study is to propose the use of artificial intelligence, namely artificial neural networks and genetic algorithms, respectively, in the simulation of oat grain yield and optimization of seeding density, considering the main succession systems of southern Brazil. The study was conducted in a randomized complete block design with four replicates, following a 4 x 2 factorial scheme, for seeding densities (100, 300, 600 and 900 seeds m-2) and oat cultivars (Brisasul and URS Taura), in succession systems of corn/oats and soybean/oats. A multi-layered artificial neural network and a genetic algorithm were...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Avena sativa; Artificial neural networks; Genetic algorithms; Innovation.
Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018000300183
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Does vertical integration reduce investment reluctance in production chains? An agent-based real options approach AgEcon
Balmann, Alfons; Musshoff, Oliver; Larsen, Karin.
This paper uses an agent-based real options approach to analyze whether stronger vertical integration reduces investment reluctance in pork production. A competitive model in which firms identify optimal investment strategies by using genetic algorithms is developed. Two production systems are compared: a perfectly integrated system and a system in which firms produce either the intermediate product (piglets) or the final product (pork). Simulations show that the spot market solution and the perfectly integrated system lead to a very similar production dynamics even with limited information on production capacities. The results suggest that, from a pure real options perspective, spot markets are not significantly inferior to perfectly integrated supply...
Tipo: Working or Discussion Paper Palavras-chave: Real options; Supply chain; Agent-based models; Genetic algorithms; Agribusiness; Agricultural and Food Policy; Agricultural Finance; Institutional and Behavioral Economics; Productivity Analysis.
Ano: 2009 URL: http://purl.umn.edu/59521
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How Smart Should Farms Be Modeled? Behavioral Foundation of Bidding Strategies in Agent-Based Land Market Models AgEcon
Kellermann, Konrad; Balmann, Alfons.
Land markets play a crucial role in agricultural structural change. Because the dynamics of structural change and land markets, respectively, mainly depend on the interactions between individual farms, agent-based modeling (ABM) has been established as a tool for understanding and explaining structural change and land market dynamics. This is particularly so because of ABM's ability to capture heterogeneity, non-convexity and dynamics. Unfortunately, the behavioral foundation of economic actors in ABM, i.e., of the farms, is often specified as ad hoc or simply based on "expert knowledge". In this contribution, the highly-detailed ABM AgriPoliS - which uses a myopic normative behavioral foundation - is coupled with a genetic algorithm (GA) to detect market...
Tipo: Conference Paper or Presentation Palavras-chave: Agent-based modeling; Genetic algorithms; Land markets; Behavioral economics; Land Economics/Use; Q12; C6.
Ano: 2006 URL: http://purl.umn.edu/25446
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Investigation of the three-dimensional lattice HP protein folding model using a genetic algorithm Genet. Mol. Biol.
Custódio,Fábio L.; Barbosa,Hélio J. C.; Dardenne,Laurent E..
An approach to the hydrophobic-polar (HP) protein folding model was developed using a genetic algorithm (GA) to find the optimal structures on a 3D cubic lattice. A modification was introduced to the scoring system of the original model to improve the model's capacity to generate more natural-like structures. The modification was based on the assumption that it may be preferable for a hydrophobic monomer to have a polar neighbor than to be in direct contact with the polar solvent. The compactness and the segregation criteria were used to compare structures created by the original HP model and by the modified one. An islands' algorithm, a new selection scheme and multiple-points crossover were used to improve the performance of the algorithm. Ten sequences,...
Tipo: Info:eu-repo/semantics/article Palavras-chave: HP model; Genetic algorithms; Protein folding.
Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572004000400023
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Multiple model approach to modelling of Escherichia coli fed-batch cultivation extracellular production of bacterial phytase Electron. J. Biotechnol.
Roeva,Olympia; Pencheva,Tania; Tzonkov,Stoyan; Arndt,Michael; Hitzmann,Bernd; Kleist,Sofia; Miksch,Gerchard; Friehs,Karl; Flaschel,Erwin.
The paper presents the implementation of multiple model approach to modelling of Escherichia coli BL21(DE3)pPhyt109 fed-batch cultivation processes for an extracellular production of bacterial phytase. Due to the complex metabolic pathways of microorganisms, the accurate modelling of bioprocesses is rather difficult. Multiple model approach is an alternative concept which helps in modelling and control of complex processes. The main idea is the development of a model based on simple submodels for the purposes of further high quality process control. The presented simulations of E. coli fed-batch cultivation show how the process could be divided into different functional states and how the model parameters could be obtained easily using genetic algorithms....
Tipo: Journal article Palavras-chave: Genetic algorithms; Modelling; Multiple model approach.
Ano: 2007 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582007000400012
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Optimierung unter Unsicherheit mit Hilfe stochastischer Simulation und Genetischer Algorithmen – dargestellt anhand der Optimierung des Produktionsprogramms eines Brandenburger Marktfruchtbetriebes AgEcon
Musshoff, Oliver; Hirschauer, Norbert.
Optimization has been recognized as a powerful tool in teaching and research for a long time. In spite of its well known problem solving capacity, some methodological obstacles have persisted over the years. The main problem is that stochastic variables and their correlations cannot be adequately accounted for within traditional optimization procedures. In this paper, we develop a methodological mix of stochastic simulation and a heuristic optimization procedure which has become known as genetic algorithms. The simulation part of the mix allows for the consideration of complex information such as stochastic processes; the genetic algorithms-part ensures that the method remains manageable in terms of required time and resources. We demonstrate the decision...
Tipo: Journal Article Palavras-chave: Optimization; Optimal production program; Stochastic simulation; Genetic algorithms; Uncertainty; Stochastic processes; Farm Management; Risk and Uncertainty.
Ano: 2004 URL: http://purl.umn.edu/97454
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Reworking the Standard Model of Competitive Markets: The Role of Fuzzy Logic and Genetic Algorithms in Modelling Complex Non-Linear Economic System AgEcon
Smith, Peter.
Some aspects of economic systems (eg, nonlinearity, qualitative variables) are intractable when incorporated into models. The widespread practice of excluding them (or greatly limiting their role) produces deviations of unknown size and form between the resulting models and the reality they purport to represent. To explore this issue, and the extent to which a change in methodology can improve tractability, a combination of two techniques, fuzzy logic and genetic algorithms, was applied to the problem of how the sellers in a freely competitive market, if initially trading at different prices, can find their way to supply/demand equilibrium. A multi-agent model was used to simulate the evolution of autonomously- learnt rule-governed behaviour, (i), under...
Tipo: Working or Discussion Paper Palavras-chave: Competition; Markets; Walrasian Crier; Equilibrium; Fuzzy logic; Genetic algorithms; Evolutionary algorithms; Industrial Organization.
Ano: 2004 URL: http://purl.umn.edu/30569
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The Spatial Agent-based Competition Model (SpAbCoM) AgEcon
Graubner, Marten.
The paper presents a detailed documentation of the underlying concepts and methods of the Spatial Agent-based Competition Model (SpAbCoM). For instance, SpAbCoM is used to study firms’ choices of spatial pricing policy (GRAUBNER et al., 2011a) or pricing and location under a framework of multi-firm spatial competition and two-dimensional markets (GRAUBNER et al., 2011b). While the simulation model is briefly introduced by means of relevant examples within the corresponding papers, the present paper serves two objectives. First, it presents a detailed discussion of the computational concepts that are used, particularly with respect to genetic algorithms (GAs). Second, it documents SpAbCoM and provides an overview of the structure of the simulation model and...
Tipo: Working or Discussion Paper Palavras-chave: Agent-based modelling; Genetic algorithms; Spatial pricing; Location model; Agent-basierte Modellierung; Genetische Algorithmen; Räumliche Preissetzung; Standortmodell; Agribusiness; Agricultural Finance; Demand and Price Analysis; Y90.
Ano: 2011 URL: http://purl.umn.edu/109915
Registros recuperados: 9
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