Wyniki wyszukiwania - Biblioteka Nauki

1

Unearthing a fossil from the history of evolutionary

100%

Fogel D. B.

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1998

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tom Vol. 35, nr 1-4

1-16

EN

All of science relies on past experimentation and hypotheses. Unfortunately, the science of evolutionary computation is hampered by a general lack of awareness of many early efforts in the field. This paper offers a review of one such contribution from 1967 which employed self-adaptation, co-evolution, and assessed the utility of recombination in various settings. The conclusions, reconfirmed in recent literature, indicate that recombination (uniform or one-point crossover) is best applied in non-epistatic settings. Theoretical analysis supported the experimental findings and now raises questions concerning common applications of schema theory to describe the behavior of evolutionary algorithms.

2

An evolutionary method of trajectory planning in collision situations at sea

80%

Śmierzchalski R.

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1998

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tom Vol. 7, no. 1/2

5-32

EN

In a collision situation at sea, the decision support system should help the operator to choose a proper manoeuvre in given circumstances, teach him good practices, and enhance his general intuition on how to behave in similar situations in future. An accepted approach in those cases is a multiple criterion decision problem. In this paper, a modified version of the EP/N (Evolutionary Planner/Navigator) algorithm - has been used as a major component of such a decision support system for computing the near optimum trajectory of a ship in given environment. By taking into account certain boundaries of the manoeuvring region, along with navigation obstacles and other moving ships, the problem of avoiding collisions at sea was reduced to a dynamic optimisation task with static and dynamic constrains. The introduction of a time parameter and moving constrains representing the passing ships is the main distinction of the new system. Sample results, having the form of ship trajectories obtained using the program for typical navigation situations are given.

3

Application of evolutionary algorithms for identification of dual phase lag model parameters

80%

Mochnacki B. , Paruch M.

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2011

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tom Vol. 10, nr 1

189-198

EN

The dual phase lag model (DPLM) based on the generalized form of Fourier law, in particular the introduction of two 'delay times' (relaxation time τq and thermalization time τT) leads to the considered form of energy equation. This equation should be applied in the case of microscale heat transfer modeling. In particular, DPLM constitutes a good approximation of thermal processes which are characterized by extremely short duration (e.g. ultrafast laser pulse), extreme temperature gradients and geometrical features of the domain considered (e.g. thin metal film). In this paper, the identification problem of two of the above mentioned positive constants τq, τT is discussed and the thermal processes proceeding in the domain of thin metal film subjected to a laser beam are analyzed. At the stage of computations connected with the identification problem solution, evolutionary algorithms are used. To solve the problem, additional information concerning the transient temperature distribution on a metal film surface is assumed to be known.

4

Evolutionary algorithms for job-shop scheduling

80%

Mesghouni K. , Hammadi S. , Borne P.

International Journal of Applied Mathematics and Computer Science

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2004

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tom 14

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nr 1

91-103

EN

This paper explains how to use Evolutionary Algorithms (EA) to deal with a flexible job shop scheduling problem, especially minimizing the makespan. The Job-shop Scheduling Problem (JSP) is one of the most difficult problems, as it is classified as an NP-complete one (Carlier and Chretienne, 1988; Garey and Johnson, 1979). In many cases, the combination of goals and resources exponentially increases the search space, and thus the generation of consistently good scheduling is particularly difficult because we have a very large combinatorial search space and precedence constraints between operations. Exact methods such as the branch and bound method and dynamic programming take considerable computing time if an optimum solution exists. In order to overcome this difficulty, it is more sensible to obtain a good solution near the optimal one. Stochastic search techniques such as evolutionary algorithms can be used to find a good solution. They have been successfully used in combinatorial optimization, e.g. in wire routing, transportation problems, scheduling problems, etc. (Banzhaf et al., 1998; Dasgupta and Michalewicz, 1997). Our objective is to establish a practical relationship between the development in the EA area and the reality of a production JSP by developing, on the one hand, two effective genetic encodings, such as parallel job and parallel machine representations of the chromosome, and on the other, genetic operators associated with these representations. In this article we deal with the problem of flexible job-shop scheduling which presents two difficulties: the first is the assignment of each operation to a machine, and the other is the scheduling of this set of operations in order to minimize our criterion (e.g. the makespan).

5

Evolutionary algorithm for economic lot and delivery scheduling problem

80%

Khouja M. , Michalewicz Z. , Vijayaragavan P.

|

1998

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tom Vol. 35, nr 1-4

113-123

EN

The economic lot and delivery scheduling problem (ELDSP) involves a supply chain consisting of a supplier and an assembly facility, where direct shipments are made from one to the other. The supplier produces multiple components on a single machine or a production line. The assembly facility uses these components at a constant rate. The supplier incurs a sequence-independent setup cost and setup time each time the production line is changed over from one component to another. On the other hand, setup costs and times for the assembly facility are negligible. There is also a fixed charge for each delivery. The problem is to find a 'just-in-time' schedule in which one production run of each component and a subsequent delivery of these components to the assembly facility occur in each cycle. The objective is to find the best sequence and cycle duration that minimizes the average cost per unit time of transportation, inventory at both the supplier and the assembly facility, and setup costs at the supplier. In this paper we investigate the usefulness of an evolutionary algorithm for solving this economic lot and delivery scheduling problem.

6

Finite Markov chain results in evolutionary computation : a tour d'horizon

80%

Rudolph G.

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1998

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tom Vol. 35, nr 1-4

67-89

EN

The theory of evolutionary computation has been enhanced rapidly during the last decade. This survey is the attempt to summarize the results regarding the limit and finite time behavior of evolutionary algorithms with finite search spaces and discrete time scale. Results on evolutionary algorithms bevond finite space and discrete time are also presented but with reduced elaboration.

7

Wpływ występowania nisz ewolucyjnych na pracę genetycznego sterownika kotła energetycznego

80%

Wójcik W. , Kalita M. , Smolarz A.

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2008

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tom R. 84, nr 3

225-227

PL

Poniższy artykuł przedstawia próbę zastosowania algorytmów genetycznych w sterowaniu kotłem energetycznym z wykorzystaniem technik niszowania. W pracy przedstawiono wyniki symulacji dla niszowania przystosowania oraz niszowania rangi osobników. Wyniki badań pokazują, że stosowanie niszowania daje korzystne rezultaty, zapobiega oraz pozwala skrócić czas obliczeń.

EN

The paper presents tests of genetic algorithms applying power boiler controller using niche technique. The results show that it allows to prevent premature convergence and reduce computation time.

8

The Cantor set generated by a simple evolutionary model

80%

Karcz-Dulęba I.

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2000

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tom z. 10

29-36

EN

Distributions of traits in a population provide important information about evolution of the population itself. In this paper an analysis of traits distributions in a phenotypic evolution is presented. A very simple model of evolution is under consideration - infinite populations evolve in one dimension space of a bimodal fitness function. The analysis of dynamic behavior of a population yields an interesting result concerning generation of the subsequent distributions. It appears that every normal distribution generates two offspring normal distributions. The evolutionary process initialized with a single normal distribution grows up to 2t normal distributions after t generations. The evolution of normal distributions is described equivalently by evolution of their parameters: means and variances. The evolution of distributions' means resembles fractals generated by an Iterated Function System (IFS). Equations describing the location of distrbutions' means in the next generation define contractive affine transformations. The defined iterative system maps the interval [0,1] into the Cantor set after infinite number of iterations.

9

Application of genetic algorithm and Fourier coefficients (GA-FC) in mechanism synthesis

80%

Starosta R.

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2008

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tom Vol. 46 nr 2

395-411

EN

The paper concerns synthesis of a four-bar linkage as a curve generator. Fourier coefficients of the curvature are applied to represent a closed curve. A genetic algorithm (GA) was adapted to solve the problem. The proposed method was successfully verified by many examples.

PL

Rozważanym zagadnieniem jest synteza czworoboku przegubowego jako generatora krzywej. Zastosowano nowy sposób reprezentowania krzywej zamkniętej za pomocą współczynników Fouriera. Do rozwiązania zadania został zaadaptowany algorytm genetyczny. Proponowana metoda została z sukcesem przetestowana na przykładach.

10

Customized crossover in evolutionary sets of safe ship trajectories

80%

Szłapczyński R. , Szłapczyńska J.

International Journal of Applied Mathematics and Computer Science

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2012

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tom 22

|

nr 4

999-1009

EN

The paper presents selected aspects of evolutionary sets of safe ship trajectories-a method which applies evolutionary algorithms and some of the assumptions of game theory to solving ship encounter situations. For given positions and motion parameters of the ships, the method finds a near optimal set of safe trajectories of all ships involved in an encounter. The method works in real time and the solutions must be returned within one minute, which enforces speeding up the optimisation process. During the development of the method the authors tested various problem-dedicated crossover operators to obtain the best performance. The results of that research are given here. The paper includes a detailed description of these operators as well as statistical simulation results and examples of experiment results.

11

Phenotypic evolution with a mutation based on symmetric α-stable distributions

80%

Obuchowicz A. , Prętki P.

International Journal of Applied Mathematics and Computer Science

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2004

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tom 14

|

nr 3

289-316

EN

Multidimensional Symmetric α-Stable (SαS) mutations are applied to phenotypic evolutionary algorithms. Such mutations are characterized by non-spherical symmetry for α<2 and the fact that the most probable distance of mutated points is not in a close neighborhood of the origin, but at a certain distance from it. It is the so-called surrounding effect (Obuchowicz, 2001b; 2003b). For α=2, the SαS mutation reduces to the Gaussian one, and in the case of α=1, the Cauchy mutation is obtained. The exploration and exploitation abilities of evolutionary algorithms, using SαS mutations for different α, are analyzed by a set of simulation experiments. The obtained results prove the important influence of the surrounding effect of symmetric α-stable mutations on both the abilities considered.

12

Optymalizacja parametrów metod redukcji bazujących na dekompozycji SVD dla celów redukcji liniowych modeli obiektów sterowania typu MIMO

80%

Rydel M. , Stanisławski W.

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2010

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tom nr 3 (23)

197-220

PL

W pracy przedstawiono zagadnienia związane z redukcją złożonych modeli liniowych z MIMO typu obiektów kontrolnych. Zostały przedstawione podstawowe metody redukcji na podstawie bilansu systemu (metody SVD), a zwłaszcza metod wprowadzania częstotliwości zwężający funkcji. Został omówiony otrzymany model na podstawie modelu strefy jednofazowej rur odparowania kotła BP-1150, wpływ parametrów metod redukcji o błędzie zbliżenia ograniczonej. Została zasugerowana optymalizacja parametrów redukcji za pomocą ewolucyjnych algorytmów. Została zbadana przydatność wielo-i jedno punktowa ewolucji algorytmów redukcji złożonych modeli na przykładzie podsystemów kotła energetycznego.

EN

The paper presents issues connected with the reduction of complex linear models of MIMO type control objects. Basic reduction methods based on a system balance (SVD methods), and especially the methods introducing the frequency tapering functions, have been presented. Based on the model of a one-phase zone of evaporating tubes the BP-1150 boiler, the influence of the parameters of the reduction methods on the approximation error of the reduced model obtained has been discussed. Optimization of the reduction parameters using evolutionary algorithms has been suggested. The usefulness of multi- and single-point evolutionary algorithms for the reduction of complex models based on the example of the power boiler subsystems has been investigated.

13

Evolutionary methods to analogue electronic circuits yield optimization

70%

Jantos P. , Rutkowski J.

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2008

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tom Vol. 56, nr 1

9-16

EN

Evolutionary computing and algorithms are well known tools of optimization that are utilized for various areas of analogue electronic circuits design and diagnosis. This paper presents the possibility of using two evolutionary algorithms - genetic algorithm and evolutionary strategies - for the purpose of analogue circuits yield and cost optimization. Terms: technologic and parametric yield are defined. Procedures of parametric yield optimization, such as a design centring, a design tolerancing, a design centring with tolerancing, are introduced. Basics of genetic algorithm and evolutionary strategies are presented, differences between these two algorithms are high-lighted, certain aspects of implementation are discussed. Effectiveness of both algorithms in parametric yield optimization has been tested on several examples and results have been presented. A share of evolutionary algorithms computation cost in a total optimization cost is analyzed.

14

A new approach to nonlinear modelling of dynamic systems based on fuzzy rules

70%

Bartczuk Ł. , Przybył A. , Cpałka K.

International Journal of Applied Mathematics and Computer Science

|

2016

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tom 26

|

nr 3

603-621

EN

For many practical weakly nonlinear systems we have their approximated linear model. Its parameters are known or can be determined by one of typical identification procedures. The model obtained using these methods well describes the main features of the system's dynamics. However, usually it has a low accuracy, which can be a result of the omission of many secondary phenomena in its description. In this paper we propose a new approach to the modelling of weakly nonlinear dynamic systems. In this approach we assume that the model of the weakly nonlinear system is composed of two parts: a linear term and a separate nonlinear correction term. The elements of the correction term are described by fuzzy rules which are designed in such a way as to minimize the inaccuracy resulting from the use of an approximate linear model. This gives us very rich possibilities for exploring and interpreting the operation of the modelled system. An important advantage of the proposed approach is a set of new interpretability criteria of the knowledge represented by fuzzy rules. Taking them into account in the process of automatic model selection allows us to reach a compromise between the accuracy of modelling and the readability of fuzzy rules.

15

Heuristic algorithms for optimization of task allocation and result distribution in peer-to-peer computing systems

70%

Chmaj G. , Walkowiak K. , Tarnawski M. , Kucharzak M.

International Journal of Applied Mathematics and Computer Science

|

2012

|

tom 22

|

nr 3

733-748

EN

Recently, distributed computing system have been gaining much attention due to a growing demand for various kinds of effective computations in both industry and academia. In this paper, we focus on Peer-to-Peer (P2P) computing systems, also called public-resource computing systems or global computing systems. P2P computing systems, contrary to grids, use personal computers and other relatively simple electronic equipment (e.g., the PlayStation console) to process sophisticated computational projects. A significant example of the P2P computing idea is the BOINC (Berkeley Open Infrastructure for Network Computing) project. To improve the performance of the computing system, we propose to use the P2P approach to distribute results of computational projects, i.e., results are transmitted in the system like in P2P file sharing systems (e.g., BitTorrent). In this work, we concentrate on offline optimization of the P2P computing system including two elements: scheduling of computations and data distribution. The objective is to minimize the system OPEX cost related to data processing and data transmission. We formulate an Integer Linear Problem (ILP) to model the system and apply this formulation to obtain optimal results using the CPLEX solver. Next, we propose two heuristic algorithms that provide results very close to an optimum and can be used for larger problem instances than those solvable by CPLEX or other ILP solvers.

16

Evolutionary sets of safe ship trajectories: development of the method

70%

Szłapczyński R. , Szłapczyńska J.

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2010

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tom nr 6

EN

The Evolutionary Sets of Safe Ship Trajectories is a method solving ship encounter situations. The method combines evolutionary approach to planning ship trajectory with some of the assumption of game theory. For given positions and motion parameters the method finds a near optimal set of safe trajectories of all ships involved in an encounter. The version presented here is an updated one and its authors have tested extensively various problem-dedicated specialized operators as well as various formulas for fitness function to obtain best effects. In the course of this process it turned out that classic evolutionary mechanisms had to be modified for better performance. Also, intuitional fitness function directly resembling goal function has been replaced with a more complex one, which includes additional COLREGS-compliance factors.

PL

Ewolucyjne zbiory bezpiecznych trajektorii statków to metoda rozwiązywania potencjalnych sytuacji kolizyjnych, łącząca podejście ewolucyjne z wybranymi założeniami teorii gier. Dla zadanych pozycji i parametrów ruchu statków metoda znajduje zbiór bezpiecznych trajektorii wszystkich statków biorących udział w spotkaniu. Omawiana jest tu druga, zaktualizowana wersja metody, przy której tworzeniu autorzy testowali różne operatory i funkcje przystosowania w celu osiągnięcia jak najlepszych wyników. W trakcie tego procesu, dla poprawienia wydajności zmieniono klasyczne mechanizmy ewolucyjne. Ponadto pierwotnie stosowana funkcja celu została zastąpiona bardziej złożoną, uwzględniającą dodatkowe kary za naruszanie prawideł MPDM.

17

Application of evolutionary algorithms to identification of diagnostic inverse models

60%

Urbanek G.

|

2006

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tom nr 2(38)

57-60

EN

Determination of two-stage models with auxiliary signals is one of possible method of inverse models identification based on examples. First stage of this diagnostic model can be a classifier based on selected features that classifies examples to predefined auxiliary signals classes. The efficiency of the model identified in this way depends on set of the selected features. The proposed method of evolutionary search of relevant features set and the obtained results of the research were described in the paper.

PL

Jedną z metod identyfikacji odwrotnych modeli diagnostycznych na podstawie przykładów jest wyznaczanie ich jako modeli dwustopniowych z użyciem sygnałów dodatkowych. Pierwszy stopień takiego modelu może być rozpatrywany jako klasyfikator, który na podstawie wybranych cech sygnałów diagnostycznych klasyfikuje przykłady do klas zdefiniowanych w przestrzeni cech sygnałów dodatkowych. Jakość tak identyfikowanego modelu zależy w głównej mierze od użytego zbioru cech sygnałów diagnostycznych. W artykule przedstawiono zaproponowaną metodę ewolucyjnego poszukiwania zbioru cech relewantnych oraz wybrane wyniki przeprowadzonych badań.

18

Pewne metody hybrydowe w jednokryterialnej optymalizacji konstrukcji

60%

Krenich S.

|

2011

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tom R. 108, z. 4-M/1

255-262

PL

W artykule przedstawiono metody optymalizacji hybrydowej i ich zastosowanie dla optymalizacji jednokryterialnej. W badaniach przeprowadzono testy z użyciem metod hybrydowych zbudowanych na podstawie turniejowego algorytmu ewolucyjnego (AE) oraz wybranych kilku metod sekwencyjnych (AS), tj. metody zmiennej tolerancji (FT), zmiennej metryki (VM), metody poszukiwań prostych (DS), metody sympleksu (SX). Przeprowadzono obliczenia dla przykładowego testu numerycznego oraz dla mechanizmu dźwigniowego chwytaka siłowego. Badania wykazały, iż połączenie metod poszukiwania globalnego (AE) przestrzeni rozwiązań z metodami przeszukiwania lokalnego (AS) prowadziło z reguły do uzyskiwania lepszych rozwiązań, przy niewielkim zwiększeniu czasu obliczeń. Ogólny algorytm tej metody ma charakter uniwersalny i może być stosowany do różnych obliczeń optymalizacyjnych.

EN

The paper presents an approach to single criteria optimization using hybrid methods. Based on tournament evolutionary algorithms (AE) and four sequential methods (AS) like a flexible tolerance method (FT), a variable matrix method (VM), a direct search method (DS), a symplex method (SX), the hybrid algorithm was implemented. During calculations two optimization problems were considered. The first one is the numerical test with several constraints and the second example deals with optimization of a robot gripper mechanism. The obtained results indicate that the combination of global and local search methods yields better results with a small increase of computation time. The algorithm of the proposed method has a universal character and can be used for wide range of optimization problems.

19

Optymalizacja rozpływu mocy w liniach wysokich napięć z wykorzystaniem algorytmu ewolucyjnego

60%

Gajer M.

|

2010

|

tom R. 86, nr 8

239-243

PL

W artykule zaproponowano wykorzystanie techniki obliczeniowej opartej na algorytmach ewolucyjnych do optymalizacji rozpływu mocy w liniach wysokich napięć. Celem rozważanej optymalizacji jest wyznaczenie wartości mocy przesyłanej za pomocą poszczególnych linii, tak aby suma mocy strat przesyłowych występujących w rozważanych liniach wysokich napięć była możliwie jak najmniejsza. Na podstawie przeprowadzonych eksperymentów numerycznych wykazano, że algorytm ewolucyjny wykorzystujący kodowanie bezpośrednio oparte na liczbach rzeczywistych jest skutecznym narzędziem optymalizacyjnym, które może znaleźć szerokie zastosowania w obszarze elektroenergetyki.

EN

The paper proposes the use of a computational technique based on evolutionary algorithms to optimize the power flow in high-voltage transmission lines. The purpose of the above mentioned optimization is to minimize the transmission losses in high-voltage lines. Based on the results of the numerical experiments we proved that the evolutionary algorithm with a coding system based directly on real numbers can be an effective optimization tool, which can be broadly implemented in the domain of electro-energetic systems.

20

Efficient variable partitioning method for functional decomposition

60%

Rawski M.

|

2007

|

tom Vol. 53, No 1

63-81

EN

In recent years the functional decomposition has found an application in many fields of modern engineering and science, such as combinational and sequential logic synthesis for VLSI systems, pattern analysis, knowledge discovery, machine learning, decision systems, data bases, data mining etc. However, its practical usefulness for very complex systems has been limited by the lack of an efficient method for selecting the appropriate input variable partitioning. This is an NP-hard problem and thus heuristic methods have to be used to efficiently and effectively search for optimal or near-optimal solutions. In this paper, a heuristic method for the input variable partitioning is discussed. The method is based on an application of evolutionary algorithms, what allows exploring the possible solution space of problem while keeping the high-quality solutions in this reduced space. The experimental results show that the proposed heuristic method is able to construct an optimal or near optimal solution very efficiently even for large systems. It is much faster than the systematic method while delivering results of comparable quality.