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1

AH Method: a Novel Routine for Vicinity Examination of the Optimum Found with a Genetic Algorithm

Piętak Daniel Andrzej, Bilski Piotr, Napiorkowski Paweł Jan

International Journal of Electronics and Telecommunications

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2022

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Vol. 68. No. 4

695--708

EN

The paper presents a novel heuristic procedure (further called the AH Method) to investigate function shape in the direct vicinity of the found optimum solution. The survey is conducted using only the space sampling collected during the optimization process with an evolutionary algorithm. For this purpose the finite model of point-set is considered. The statistical analysis of the sampling quality based upon the coverage of the points in question over the entire attraction region is exploited. The tolerance boundaries of the parameters are determined for the user-specified increase of the objective function value above the found minimum. The presented test-case data prove that the proposed approach is comparable to other optimum neighborhood examination algorithms. Also, the AH Method requires noticeably shorter computational time than its counterparts. This is achieved by a repeated, second use of points from optimization without additional objective function calls, as well as significant repository size reduction during preprocessing.

2

Analog circuits specification driven testing by the means of digital stream and non-linear estimation model optimized evolutionarily

Golonek T., Chruszczyk Ł.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2020

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Vol. 68, nr 6

1283--1299

EN

The method described in this work allows to determine the optimal distribution of pulses of digital signal as well as the non-linear mathematical model based on a multiple regression statistical analysis, which are specialized to an effective and low-cost testing of functional parameters in analog electronic circuits. The aim of this concept is to simplify the process of analog circuit specification validation and minimize hardware implementation, time and memory requirements during the testing stage. This strategy requires simulations of the analyzed analog electronic circuit; however, this effort is done only once – before the testing stage. Then, validation of circuit specification can be obtained after a quick, very low-cost procedure without time consuming computations and without expensive external measuring equipment usage. The analyzed test signature is a time response of the analog circuit to the stream of digital pulses for which distributions were determined during evolutionary optimization cycles. Besides, evolutionary computations assure determination of the optimal form and size of the non-linear mathematical formula used to estimate specific functional parameters. Generally, the obtained mathematical model has a structure similar to the polynomial one with terms calculated by means of multiple regression procedure. However, a higher ordered polynomial usage makes it possible to reach non-linear estimation model that improves accuracy of circuit parametric identification. It should be noted that all the evolutionary calculations are made only at the before test stage and the main computational effort, for the analog circuit specification test design, is necessary only once. Such diagnosing system is fully synchronized by a global digital signal clock that precisely determines time points of the slopes of input excitation pulses as well as acquired output signature samples. Efficiency of the proposed technique is confirmed by results obtained for examples based on analog circuits used in previous (and other) publications as test benchmarks.

3

An efficient approach for view selection for data warehouse using tree mining and evolutionary computation

Thakare A., Deshpande P.

Computer Science

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2018

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Vol. 19 (4)

431--455

EN

The selection of a proper set of views to materialize plays an important role in database performance. There are many methods of view selection that use different techniques and frameworks to select an efficient set of views for materialization. In this paper, we present a new efficient scalable method for view selection under the given storage constraints using a tree mining approach and evolutionary optimization. The tree mining algorithm is designed to determine the exact frequency of (sub)queries in the historical SQL dataset. The Query Cost model achieves the objective of maximizing the performance benefits from the final view set that is derived from the frequent view set given by the tree mining algorithm. The performance benefit of a query is defined as a function of query frequency, query creation cost, and query maintenance cost. The experimental results show that the proposed method is successful in recommending a solution that is fairly close to an optimal solution.

4

Zastosowanie obliczeń ewolucyjnych w zagadnieniach związanych z analizą sieci hydraulicznych

Handzel Z., Gajer M., Jamróz D.

Elektronika : konstrukcje, technologie, zastosowania

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2015

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Vol. 56, nr 1

56-58

PL

W artykule zaproponowano wykorzystanie algorytmów ewolucyjnych w celu przeprowadzania analizy oczkowych sieci hydraulicznych. Zadaniem algorytmu ewolucyjnego jest wyznaczenie wartości przepływów w poszczególnych gałęziach arbitralnie zadanej sieci hydraulicznej. W artykule zaproponowano sposób kodowania rozwiązań na materiale genetycznym ewoluujących osobników oraz zdefiniowano postać funkcji dopasowania pozwalającej na ocenę rozwiązań odnajdowanych w toku procesów ewolucyjnych.

EN

In the paper we propose to use evolutionary algorithms for the purpose of analysis of hydraulic networks. The aim of evolutionary algorithm is to determine the values of flow in the branches of arbitrarily given hydraulic network. In the paper we propose the way of coding of solutions on genetic material of evolving individuals and we define the fitness function to evaluate solutions found during the process of evolution.

5

Multi-objective optimization with adjusted PSO method on example of cutting process of hardened 18CrMo4 steel

Stryczek R., Pytlak B.

Eksploatacja i Niezawodność

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2014

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Vol. 16, no. 2

236--245

PL

W pracy zaproponowano zmodyfikowaną metodę optymalizacji wielocząsteczkowej (PSO) dla problemów optymalizacji wielokryterialnej z dyskretną przestrzenią decyzyjną. W metodzie PSO zmieniono sposób określania momentu bezwładności, współczynnika uczenia oraz współczynnika społecznego. Dodatkowo wprowadzono elitaryzm oraz innowacyjny mechanizm hamowania cząstek chroniący je przed przekraczaniem dopuszczalnych granic przestrzeni decyzyjnej. Zaproponowane podejście zostało zweryfikowane na szeregu aktualnych funkcjach testowych oraz problemie optymalizacji procesu skrawania stali 18CrMo4 w stanie zahartowanym, gdzie porównano je z wynikami uzyskanymi za pomocą algorytmów genetycznych (GA). Uzyskane wyniki wskazują, że zaproponowane podejście jest względnie szybkie i wysoce konkurencyjne w stosunku do innych metod optymalizacji. Autorzy uzyskali bardzo różnorodne, zbieżne i w pełnym zakresie przebiegi frontu Pareto w przestrzeni kryteriów. W celu oceny jakości wygenerowanego zbioru Pareto dla każdego z prezentowanych przykładów wyznaczono ocenę opartą na pomiarze entropii oraz wskaźnika jakości IGD.

EN

In this paper a Modified Particle Swarm Optimization (PSO) method for multi-objective (MO) problems with a discrete decision space is proposed. In the PSO method the procedure to determine inertia weight, learning factor and social factor is modified. In addition, both an elitism strategy and innovative deceleration mechanism preventing the particles from going beyond the limits of decision space are introduced. The proposed approach has been applied to a series of currently used test functions as well as to optimization problems connected with finish hard turning operation, where the obtained results have been compared with those obtained by means of Genetic Algorithms (GA). The results indicate that the proposed approach is relatively quick, and thus it is highly competitive with other optimization methods. The authors have obtained a very good diversity, convergence and a maximum range of the Pareto front in the criteria space. In order to assess the quality of the generated Pareto set for each of presented examples, a rating has been determined based on the entropy measurement and inverted generational distance (IGD).

6

Optymalizacja systemów elektroenergetycznych z zastosowaniem obliczeń ewolucyjnych

Gajer M.

Pomiary Automatyka Robotyka

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2013

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R. 17, nr 2

345-350

PL

Tematyka artykułu dotyczy zagadnień związanych z optymalizacją pracy urządzeń wchodzących w skład systemu elektroenergetycznego. W artykule optymalizacja sposobu pracy urządzeń systemu elektroenergetycznego została potraktowana jako optymalizacja wielokryterialna. Głównymi kryteriami branymi pod uwagę podczas poszukiwania rozwiązania są przede wszystkim koszt produkcji energii elektrycznej w rozpatrywanym horyzoncie czasowym oraz całkowita moc termicznych strat przesyłowych powstających w liniach wysokich napięć. Ponadto moc w systemie elektroenergetycznym powinna być zbilansowana, co stanowi kolejne kryterium oceny jakości uzyskiwanych rozwiązań. W celu rozwiązania rozpatrywanego w artykule zagadnienia optymalizacyjnego zaproponowano wykorzystanie techniki obliczeń ewolucyjnych.

EN

The topic of the paper is about the optimization of the mode of work of electrical energetic systems. This kind of optimization is considered as multi-objective optimization. The main criteria that are taken under account are the amount of fuel burnt in energetic blocks in the time unit and total thermal losses in power transmission lines. In the paper in order to solve such multi-objective optimization problem the computational technique base on the use of evolutionary algorithms was implemented.

7

Stimulus with limited band optimization for analogue circuit testing

Golonek T., Jantos P., Rutkowski J.

Metrology and Measurement Systems

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2012

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Vol. 19, nr 1

73-84

EN

The paper presents an analogue circuit testing method that engages the analysis of the time response to a nonperiodic stimulus specialized for the verification of selected specifications. The decision about the current circuit diagnostic state depends on an amplitude spectrum decomposition of the time response measured during the test. A shape of the test excitation spectrum is optimized with the use of a differential evolution algorithm and it allows for achieving maximum fault coverage and the optimal conditions for fault isolation. Genotypes of the evolutionary system encode the amplitude spectrum of candidates for testing stimuli by means of rectangle frequency windows with amplitudes determined evolutionarily.

8

The use of specialized multi-band stimuli for analog circuits testing

Golonek T., Jantos P., Grzechca D.

Elektronika : konstrukcje, technologie, zastosowania

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2011

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Vol. 52, nr 12

47-49

EN

This paper presents the method of an analog functional testing which applies a non-periodic responses analyzing during the testing stage. The difference of energy levels for responses obtained to a pair of optimized stimuli was engaged to a circuit state determination. The proposed testing excitations have multi-band spectra of amplitude densities and they are specialized for investigation of assumed specifications. The amplitude densities of stimuli are optimized by means of evolutionary computations. Each population of evolutionary system consists of real numbered vectors which contain approximation coefficients for spectra of multi-band stimuli candidates.

PL

W artykule opisano metodę funkcjonalnego testowania elektronicznych układów analogowych wykorzystującą analizę aperiodycznych odpowiedzi układu na wielopasmowe pobudzenia specjalizowane. Klasyfikacja poziomu wybranych specyfikacji obwodu jest dokonywana na podstawie oceny wartości różnicy energii otrzymanych dla pary zoptymalizowanych pobudzeń testujących. W celu osiągnięcia wysokiej skuteczności izolacji stanów obwodu testowanego, funkcje gęstości widmowych pobudzeń specjalizowanych są optymalizowane na etapie przed testowym w toku ewolucji różnicowej. Populacja osobników systemu ewolucyjnego zawiera zestawy rzeczywistych współczynników aproksymujących funkcje kodujące potencjalne spektra częstotliwościowe pobudzeń.

9

Analysis of semantic modularity for genetic programming

Krawiec K., Wieloch B.

Foundations of Computing and Decision Sciences

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2009

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Vol. 34, No. 4

265-285

EN

In this paper we analyze the properties of functional modularity, a concept introduced in [14] for detecting and measuring modularity in problems of automatic program synthesis, in particular by means of genetic programming. The basic components of functional modularity approach are subgoals - entities that embody module's semantic - and monotonicity, a measure for assessing subgoals' potential utility for searching for good modules. For a given subgoal and a sample of solutions decomposed into parts and contexts according to module definition, monotonicity measures the correlation of distance between semantics of solution's part and the fitness of the solution. The central tenet of this approach is that highly monotonous subgoals can be used to decompose the task and improve search convergence. In the experimental part we investigate the properties of functional modularity using eight instances of problems of Boolean function synthesis. The results show that monotonicity varies depending on problem's structure of modularity and correctly identifies good subgoals, potentially enabling automatic program decomposition.

10

An agent-based, self-tuning, population learning algorithm for the resource constrained project scheduling

Jędrzejowicz P., Ratajczak-Ropel E.

Foundations of Computing and Decision Sciences

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2007

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Vol. 32, No. 3

213-225

EN

The authors propose an agent-based population-learning algorithm (PLA) designed for solving the RCPSP and the MRCPSP. The paper contains problem formulation and a description of the proposed implementation of the PLA. The resulting multiple-agent system has been implemented using the JABAT environment designed with a view to facilitate development of a-teams. To validate the approach a computational experiment has been earned out. It has involved instances obtained from the available benchmark data sets. Results of the experiment show that the proposed implementation can serve as an effective tool for solving the resource-constrained project scheduling problems.

11

Ewolucyjny dobór częstotliwości sygnałów testujących z rozmytą inicjalizacją systemu

Golonek T., Grzechca D., Rutkowski J.

Elektronika : konstrukcje, technologie, zastosowania

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2007

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Vol. 48, nr 11

72-75

PL

Przedstawiono ewolucyjną metodę optymalizacji zestawu częstotliwości dla sinusoidalnych pobudzeń, testujących analogowe układy elektroniczne. Proponowana technika wykorzystuje zbiory niejednoznaczności i zmodyfikowany algorytm genetyczny z funkcją przystosowania wykorzystującą zestaw reguł eksperckich systemu rozmytego oraz metodą ważoną. Prezentowane rozwiązanie pozwala uzystać wysoką skuteczność dla praktycznych obwodów z uwzględnieniem rozrzutu tolerancyjnego i błędów pomiarowych. Algorytm został zaimplementowany z wykorzystaniem procesora wbudowanego MicroBlaze na platformie Virtex4 ML-401.

EN

The evolutionary technique of test frequencies selection for analog sinusoidal stimuli set is described in this paper. The proposed method bases on ambiguity set concept and evolutionary algorithm that has been executed for fuzzy and weighted fitness functions. The proposed approach to analog testing allows to achieve high efficiency for practical circuits under test with tolerance dispersions and test inaccuracies presence. Optimization system has been implemented with the use of the MicroBlaze embedded processor on Virtex4 ML-401 platform.

12

Niching mechanisms in evolutionary computations

Kowalczuk Z., Białaszewski T.

International Journal of Applied Mathematics and Computer Science

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2006

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Vol. 16, no 1

59-84

EN

Different types of niching can be used in genetic algorithms (GAs) or evolutionary computations (ECs) to sustain the diversity of the sought optimal solutions and to increase the effectiveness of evolutionary multi-objective optimization solvers. In this paper four schemes of niching are proposed, which are also considered in two versions with respect to the method of invoking: a continuous realization and a periodic one. The characteristics of these mechanisms are discussed, while as their performance and effectiveness are analyzed by considering exemplary multi-objective optimization tasks both of a synthetic and an engineering (FDI) design nature.