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2. A neural network based selection method for genetic algorithms
- Creator:
- Yalkin, Can and Korkmaz, Erkan
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Genetic algorithms, neural networks, selection, and hybrid algorithms
- Language:
- English
- Description:
- Genetic algorithms (GAs) are stochastic methods that are widely used in search and optimization. The breeding process is the main driving mechanism for GAs that leads the way to find the global optimum. And the initial phase of the breeding process starts with parent selection. The selection utilized in a GA is effective on the convergence speed of the algorithm. A GA can use different selection mechanisms for choosing parents from the population and in many applications the process generally depends on the fitness values of the individuals. Artificial neural networks (ANNs) are used to decide the appropriate parents by the new hybrid algorithm proposed in this study. And the use of neural networks aims to produce better offspring during the GA search. The neural network utilized in this algorithm tries to learn the structural patterns and correlations that enable two parents to produce high-fit offspring. In the breeding process, the first parent is selected based on the fitness value as usual. Then it is the neural network that decides the appropriate mate for the first parent chosen. Hence, the selection mechanism is not solely dependent on the fitness values in this study. The algorithm is tested with seven benchmark functions. It is observed from results of these tests that the new selection method leads genetic algorithm to converge faster.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
3. Darwinismus a portmannismus: střetnutí nesouměřitelných biologických paradigmat?
- Creator:
- Filip Jaroš
- Type:
- model:article and TEXT
- Subject:
- filozofie, philosophy, Portmann, darwinismus, selekce, testovatelnost teorií, paradigma, Darwinism;, selection, stability of theories, 5, and 101
- Language:
- Czech
- Description:
- Tzv. portmannismus je specifický, v biologii kořenící myšlenkový směr, jehož dosah je v současné době omezen převážně na české země. Řada prací ukazuje, že na platformě Portmannových myšlenek vznikla v Čechách originální myšlenková škola. Portmann uznával Darwinovu teorii, upozorňoval však na množství jevů, které si žádají interpretaci nad rámec známých darwinistických mechanismů. Mezi zastánci Portmannovy nauky a hlavním proudem (neo) darwinistů existuje napětí vyrůstající z různých pojetích vědy. Portmannismus je často považován za nauku mířící mimo oblast vědy. Analýza se zabývá oprávněností takových poukazů a zasazuje je do kontextu teorie vědy. Ukazuje, že přes rozdíly v cílech a užitích metodologických prostředků není hranice mezi oběma přístupy ostře dána. Připomíná skutečnost, že od doby přenesení Portmannových myšlenek do českých zemí došlo ke generační obměně jejich nositelů. Portmannismus lze z hledisek teoretických, faktických i sociálních do jisté míry smířit s hlavním proudem vědy., The article examines the possibility of cultivating biology inspired by a biologist A. Portmann. The problem is to some extent limited to the Czech language area, where Portmann’s ideas are relatively well established. The paper analyses the causes of latent tension between so-called Darwinists and Portmannists. It must be emphasized that Portmann did not disregard Darwin’s theory. The article aims to show that Portmann’s ideas transcend traditional Darwinian reduction of life form to adaptive function. Divergence of these schools of thought comes from different opinions on the nature of science. Th e paper shows how the dissimilarities of aims and means of biological exploration lead to different conclusions about living creatures. For research that would grow out of Portmann’s ideas, it is necessary not to consider Darwinism as a competitor, but as a thought-provoking partner for a dialogue., and Filip Jaroš.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
4. Ecophysiological consequences of variability in diapause intensity
- Creator:
- Masaki, Sinzo
- Type:
- article, model:article, and TEXT
- Subject:
- Diapause, intensity, variability, cline, selection, genetics, polymorphism, and seasonal cue
- Language:
- English
- Description:
- Diapause intensity (DI) is a physiological trait represented by the duration of diapause under given conditions of environment. In many species, it is highly variable, probably being controlled by multiple genes and tends to form a cline in response to the latitudinal gradient of selection pressure. DI clines could be established artificially by crossing between lines of a cricket selected for different levels of DI, indicating the importance of genetic factors in the adaptive variation of DI. However, DI may be modified in response to seasonal cues both before and after the onset of diapause. Polymorphism in the intensity of prolonged diapause may split adults of a single population to emerge in different years. A unimodal distribution of DI may also result in polymodal termination of diapause, if DI variation is so large that chilling in one winter is not enough to terminate diapause for all members of a population. Bimodal termination of diapause after overwintering suggests heterogeneity in the final phase of diapause that requires high temperatures in spring. Polymodal termination of diapause subserves a bet-hedging strategy. Variability in DI thus provides insects with an important means of adaptation to their environments changing in space and time.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
5. Egg-dumping behaviour in the seed beetle Acanthoscelides obtectus (Coleoptera: Chrysomelidae: Bruchinae) selected for early and late reproduction
- Creator:
- Šešlija, Darka, Stojković, Biljana, Tucić, Branka, and Tucić, Nikola
- Type:
- article, model:article, and TEXT
- Subject:
- Chrysomelidae, Bruchinae, Acanthoscelides obtectus, egg-dumping, selection, and longevity
- Language:
- English
- Description:
- In the present study the egg dumping behaviour in short (E)- and long (L)-lived lines of the seed beetle Acanthoscelides obtectus was analyzed. Females of the short-lived E line exhibited substantially higher egg dumping than long-lived L line females. We hypothesize that, since cessation of egg dumping enhances longevity, non-dumping females were selectively favoured in the L regime. Our study also produced evidence that the selection regime affected the male's ability to influence female egg-dumping behaviour. The females mated to males from the lines that were selected for extended longevity and of which the females exhibited little egg-dumping dumped fewer eggs. We suggest that in the L selection regime, where offspring produced at the end of the females' reproductive period were recruited to the next generation, selection operated against those males that stimulated female oviposition in the absence of seeds. This is the first study to provide evidence that selection for long-lived insects results in the reduced potency of male seminal products to stimulate female oviposition.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
6. Upper quasi continuous maps and quasi continuous selections
- Creator:
- Matejdes, Milan
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- selection, quasi continuity, minimal usco multifunction, cluster point, and generalized quasi continuity
- Language:
- English
- Description:
- The paper deals with the existence of a quasi continuous selection of a multifunction for which upper inverse image of any open set with compact complement contains a set of the form $(G\setminus I)\cup J$, where $G$ is open and $I$, $J$ are from a given ideal. The methods are based on the properties of a minimal multifunction which is generated by a cluster process with respect to a system of subsets of the form $(G\setminus I)\cup J$.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public