Speeding Up Evolutionary Algorithms through Asymmetric Mutation Operators

2007 ◽  
Vol 15 (4) ◽  
pp. 401-410 ◽  
Author(s):  
Benjamin Doerr ◽  
Nils Hebbinghaus ◽  
Frank Neumann
Keyword(s):  
Lower Bound ◽  
Evolutionary Algorithms ◽  
Upper Bounds ◽  
Point Of View ◽  
Theoretical Point ◽  
Mutation Operator ◽  
Linear Factor ◽  
Mutation Operators ◽  
Variation Operators

Successful applications of evolutionary algorithms show that certain variation operators can lead to good solutions much faster than other ones. We examine this behavior observed in practice from a theoretical point of view and investigate the effect of an asymmetric mutation operator in evolutionary algorithms with respect to the runtime behavior. Considering the Eulerian cycle problem we present runtime bounds for evolutionary algorithms using an asymmetric operator which are much smaller than the best upper bounds for a more general one. In our analysis it turns out that a plateau which both algorithms have to cope with changes its structure in a way that allows the algorithm to obtain an improvement much faster. In addition, we present a lower bound for the general case which shows that the asymmetric operator speeds up computation by at least a linear factor.

scholarly journals BÜCHI COMPLEMENTATION MADE TIGHTER

2006 ◽  
Vol 17 (04) ◽  
pp. 851-867 ◽  
Author(s):  
EHUD FRIEDGUT ◽  
ORNA KUPFERMAN ◽  
MOSHE Y. VARDI
Keyword(s):  
Lower Bound ◽  
Upper Bound ◽  
Blow Up ◽  
Careful Analysis ◽  
Point Of View ◽  
Upper And Lower Bounds ◽  
Theoretical Point ◽  
Infinite Words ◽  
Büchi Automata ◽  
Buchi Automata

The complementation problem for nondeterministic word automata has numerous applications in formal verification. In particular, the language-containment problem, to which many verification problems is reduced, involves complementation. For automata on finite words, which correspond to safety properties, complementation involves determinization. The 2n blow-up that is caused by the subset construction is justified by a tight lower bound. For Büchi automata on infinite words, which are required for the modeling of liveness properties, optimal complementation constructions are quite complicated, as the subset construction is not sufficient. From a theoretical point of view, the problem is considered solved since 1988, when Safra came up with a determinization construction for Büchi automata, leading to a 2O(n log n) complementation construction, and Michel came up with a matching lower bound. A careful analysis, however, of the exact blow-up in Safra's and Michel's bounds reveals an exponential gap in the constants hiding in the O( ) notations: while the upper bound on the number of states in Safra's complementary automaton is n2n, Michel's lower bound involves only an n! blow up, which is roughly (n/e)n. The exponential gap exists also in more recent complementation constructions. In particular, the upper bound on the number of states in the complementation construction of Kupferman and Vardi, which avoids determinization, is (6n)n. This is in contrast with the case of automata on finite words, where the upper and lower bounds coincides. In this work we describe an improved complementation construction for nondeterministic Büchi automata and analyze its complexity. We show that the new construction results in an automaton with at most (0.96n)n states. While this leaves the problem about the exact blow up open, the gap is now exponentially smaller. From a practical point of view, our solution enjoys the simplicity of the construction of Kupferman and Vardi, and results in much smaller automata.

Analysis of an Asymmetric Mutation Operator

2010 ◽  
Vol 18 (1) ◽  
pp. 1-26 ◽  
Author(s):  
Thomas Jansen ◽  
Dirk Sudholt
Keyword(s):  
Evolutionary Algorithms ◽  
Random Search ◽  
Mutation Operator ◽  
Asymptotic Results ◽  
Randomized Search Heuristics ◽  
Function Classes ◽  
Search Heuristics ◽  
Speed Up ◽  
Variation Operators ◽  
Randomized Search

Evolutionary algorithms are general randomized search heuristics and typically perform an unbiased random search that is guided only by the fitness of the search points encountered. However, in applications there is often problem-specific knowledge that suggests some additional bias. The use of appropriately biased variation operators may speed up the search considerably. Problems defined over bit strings of finite length often have the property that good solutions have only very few 1-bits or very few 0-bits. A mutation operator tailored toward such situations is studied under different perspectives and in a rigorous way discussing its assets and drawbacks. We consider the runtime of evolutionary algorithms using biased mutations on illustrative example functions as well as on function classes. A comparison with unbiased operators shows on which functions biased mutations lead to a speedup, on which functions biased mutations increase the runtime, and in which settings there is almost no difference in performance. The main focus is on theoretical runtime analysis yielding asymptotic results. These findings are accompanied by the results of empirical investigations that deliver additional insights.

scholarly journals Application of the variation operator in a genetic algorithm for the synthesis of fuzzy controllers

2021 ◽  
Vol 47 (4) ◽  
pp. 92-100
Author(s):  
I. V. Kulikova
Keyword(s):  
Genetic Algorithm ◽  
Control System ◽  
Fuzzy Controller ◽  
Single Point ◽  
Controller Synthesis ◽  
Mutation Operator ◽  
Mutation Operators ◽  
Variation Operator ◽  
Variation Operators ◽  
Best Parameters

Abstract. Objective. This article studies the problem of increasing the efficiency of fuzzy controller synthesis in a control system using a genetic algorithm. The best parameters of the fuzzy controller are selected using the crossing-over and mutation operators in the genetic algorithm. The operation of the mutation operator can lead to the formation of an incorrect set of parameters, which complicates the procedure for synthesizing a fuzzy controller.Methods. Arrays of parameter sets of membership functions, conclusions, and rule weights that are included in the fuzzy controller are compiled using mathematical simulation. The mechanism of operation of single-point and two-point variation operators in the genetic algorithm is described by the simulation modeling.Results. Mathematical models of single-point and two-point variation operators for the genetic algorithm are proposed. The mechanism for changing the values of elements in the array of a set of parameters of a fuzzy controller with one input and output variable is presented.Conclusion. Replacing the mutation operator with the variation operator eliminates the formation of incorrect sets of parameters of the fuzzy controller in the control system.

Timber Auctions in the Context of the Modern Auction Theory

2007 ◽  
pp. 86-94
Author(s):  
A. Manakov
Keyword(s):  
Theoretical Analysis ◽  
Auction Theory ◽  
Point Of View ◽  
Theoretical Point ◽  
English Auction ◽  
Analysis And Evaluation

The article provides theoretical analysis and evaluation of the timber auctions reforms in Russia. The author shows that the mechanism of the "combined auctions", which functioned until recently, is more appropriate from the theoretical point of view (and from the point of view of the Russian practice) as compared to the officially approved format of the English auction.

A novel cryptosystem based on abstract automata and Latin cubes

2015 ◽  
Vol 52 (2) ◽  
pp. 221-232
Author(s):  
Pál Dömösi ◽  
Géza Horváth
Keyword(s):  
Block Cipher ◽  
Finite Automata ◽  
Theoretical Background ◽  
Point Of View ◽  
Theoretical Point ◽  
Transition Matrices ◽  
Encryption And Decryption ◽  
Secret Keys ◽  
Automata Network ◽  
Fully Functioning

In this paper we introduce a novel block cipher based on the composition of abstract finite automata and Latin cubes. For information encryption and decryption the apparatus uses the same secret keys, which consist of key-automata based on composition of abstract finite automata such that the transition matrices of the component automata form Latin cubes. The aim of the paper is to show the essence of our algorithms not only for specialists working in compositions of abstract automata but also for all researchers interested in cryptosystems. Therefore, automata theoretical background of our results is not emphasized. The introduced cryptosystem is important also from a theoretical point of view, because it is the first fully functioning block cipher based on automata network.

Graffiti als Version und Subversion–Praxen kultureller Re-Regulierung und die Möglichkeit von Gratiforschung

2010 ◽  
Vol 55 (2) ◽  
pp. 11-25 ◽  
Author(s):  
Bernd Dollinger
Keyword(s):  
Social Life ◽  
Point Of View ◽  
Theoretical Point ◽  
Research Practice ◽  
Wird Eine ◽  
Multiple Perspectives

Der Beitrag geht von Versuchen aus, integrative Perspektiven einer überaus heterogenen Graffitiforschung zu bestimmen. In Auseinandersetzung insbesondere mit Bruno Latours Ansatz des »Iconoclash« wird eine kulturtheoretische Referenz bestimmt, die Graffiti als Version identifiziert, d. h. als semiotisch orientierte Veränderung räumlich situierter Ordnungs- und Regulierungspraxen. Ihnen kann, wenn auch nicht zwingend, eine subversive Qualität zukommen. Durch die Ausrichtung am Konzept einer Version wird beansprucht, Forderungen einer normativ weitgehend abstinenten, nicht-essentialistischen und für komplexe Fragen der Identitäts- und Raumpolitik offenen Forschungspraxis einzulösen.<br><br>The contribution attempts to integrate multiple perspectives of current largely heterogeneous graffiti scholarship. Referring to Bruno Latour’s concept »iconoclash«, we discuss graffiti from a cultural-theoretical point of view as a »version«. It appears as a semiotically oriented modification of spatially situated practices that regulate social life. Often, but not necessarily, these practices involve subversive qualities. The concept of »version« facilitates a non-normative and non-essentialist strategy of research. This enables an explorative research practice in which the complex matters of identity and space politics that are associated with graffiti can be addressed.

scholarly journals How Digital Inclusion Increase Opportunities for Young People: Case of NEETs from Bulgaria, Romania and Turkey

2021 ◽  
Vol 13 (14) ◽  
pp. 7894
Author(s):  
Gabriela Neagu ◽  
Muhammet Berigel ◽  
Vladislava Lendzhova
Keyword(s):  
Data Analysis ◽  
Rural Areas ◽  
Secondary Data ◽  
Point Of View ◽  
Multidimensional Analysis ◽  
Theoretical Point ◽  
Digital Inclusion ◽  
Virtual Mobility ◽  
Alternative Research ◽  
High Share

This paper examines the perspectives of rural NEETs in the information society. Our analysis focuses on the situation of three European countries—Bulgaria, Romania, and Turkey—characterized by a high share of rural areas and a population of NEETs. From a methodological point of view, we use alternative research methods (secondary data analysis) with statistical methods (simple linear regression). From a theoretical point of view, we will opt for a multidimensional analysis perspective: the theory of digital divide, digital inclusion, virtual mobility, etc. Through data analysis, we expect to obtain a more complete and detailed picture of the ICT situation in rural areas (level of digital skills, level of digital inclusion) to demonstrate the importance of ICT in optimizing virtual mobility for the living conditions of the population, especially the NEET population.

scholarly journals Verbena officinalis Verbenaceae (Lamiales): a new plant model system for phyllotaxis research

2021 ◽  
Author(s):  
Beata Zagórska-Marek ◽  
Magdalena Turzańska ◽  
Klaudia Chmiel
Keyword(s):  
Vascular System ◽  
Cumulative Effect ◽  
Point Of View ◽  
Theoretical Point ◽  
Inflorescence Axis ◽  
Organ Identity ◽  
Lateral Organ ◽  
Complex Relationships ◽  
Secondary Transitions

AbstractPhyllotactic diversity and developmental transitions between phyllotactic patterns are not fully understood. The plants studied so far, such as Magnolia, Torreya or Abies, are not suitable for experimental work, and the most popular model plant, Arabidopsis thaliana, does not show sufficient phyllotactic variability. It has been found that in common verbena (Verbena officinalis L.), a perennial, cosmopolitan plant, phyllotaxis differs not only between growth phases in primary transitions but also along the indeterminate inflorescence axis in a series of multiple secondary transitions. The latter are no longer associated with the change in lateral organ identity, and the sequence of phyllotactic patterns is puzzling from a theoretical point of view. Data from the experiments in silico, confronted with empirical observations, suggest that secondary transitions might be triggered by the cumulative effect of fluctuations in the continuously decreasing bract primordia size. The most important finding is that the changes in the primary vascular system, associated with phyllotactic transitions, precede those taking place at the apical meristem. This raises the question of the role of the vascular system in determining primordia initiation sites, and possibly challenges the autonomy of the apex. The results of this study highlight the complex relationships between various systems that have to coordinate their growth and differentiation in the developing plant shoot. Common verbena emerges from this research as a plant that may become a new model suitable for further studies on the causes of phyllotactic transitions.

scholarly journals Modeling and theoretical description of magnetic hybrid materials—bridging from meso- to macro-scales

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Andreas M. Menzel ◽  
Hartmut Löwen
Keyword(s):  
Colloidal Particles ◽  
Colloidal Particle ◽  
Theoretical Description ◽  
Point Of View ◽  
Material Behavior ◽  
Theoretical Point ◽  
Mechanical Stiffness ◽  
Theoretical Approaches ◽  
Theoretical Predictions ◽  
Particle Level

Abstract Magnetic gels and elastomers consist of magnetic or magnetizable colloidal particles embedded in an elastic polymeric matrix. Outstanding properties of these materials comprise reversible changes in their mechanical stiffness or magnetostrictive distortions under the influence of external magnetic fields. To understand such types of overall material behavior from a theoretical point of view, it is essential to characterize the substances starting from the discrete colloidal particle level. It turns out that the macroscopic material response depends sensitively on the mesoscopic particle arrangement. We have utilized and developed several theoretical approaches to this end, allowing us both to reproduce experimental observations and to make theoretical predictions. Our hope is that both these paths help to further stimulate the interest in these fascinating materials.

The expectation marker of course in a cross-linguistic perspective

2004 ◽  
Vol 4 (1) ◽  
pp. 13-43 ◽  
Author(s):  
Anne-Marie Simon-Vandenbergen ◽  
Karin Aijmer
Keyword(s):  
English Learners ◽  
Native Speakers ◽  
Point Of View ◽  
Theoretical Point ◽  
Pragmatic Markers ◽  
Semantic Fields ◽  
Explanatory Account ◽  
Semantics And Pragmatics ◽  
Multilingual Corpus ◽  
Core Meaning

The study of of course presented in this article has an applied, a descriptive and a theoretical aim. Since of course proves to be very frequent in English, learners will need to know what meanings the item has and in what pragmatic contexts it is used. It has indeed been shown that some learners tend to use of course in contexts where it is felt by native speakers to be inappropriate. In order to explain such inappropriate uses we need detailed descriptions of the semantics and pragmatics of of course. From a theoretical point of view such multifunctional items raise the question of whether semantic polysemy or pragmatic polysemy is the best explanatory account. It is argued in this paper that empirical cross-linguistic work can contribute to providing answers to all three research questions. First, the study of correspondences and differences between languages with regard to the meanings and uses of pragmatic markers is a necessary step in the explanation of learner problems. Second, the bidirectional approach to equivalents, which involves going back and forth from sources to translations, enables us to show to what extent the equivalents have partially overlapping pragmatic functions. An in-depth comparison of the semantic fields in which the translation equivalents operate is the ultimate goal. Third, the translation method helps to see to what extent a core meaning account is justified. In this paper three languages are brought into the picture, viz. English, Swedish and Dutch. The cross-linguistic data have been gathered from three translation corpora, i.e. the English-Swedish Parallel Corpus, the Oslo Multilingual Corpus and the Namur Triptic Corpus.

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