Wyniki wyszukiwania - BazTech

1

Scaling laws for the FE solutions of induction machines

Nell Martin, Lenz Jonas, Hameyer Kay

Archives of Electrical Engineering

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2019

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Vol. 68, nr 3

677--695

EN

In this paper a scaling approach for the solution of 2D FE models of electric machines is proposed. This allows a geometrical and stator and rotor resistance scaling as well as a rewinding of a squirrel cage induction machine enabling an efficient numerical optimization. The 2D FEM solutions of a reference machine are calculated by a model based hybrid numeric induction machine simulation approach. In contrast to already known scaling procedures for synchronous machines the FEM solutions of the induction machine are scaled in the stator-current-rotor-frequency-plane and then transformed to the torque-speed-map. This gives the possibility to use a new time scaling factor that is necessary to keep a constant field distribution. The scaling procedure is validated by the finite element method and used in a numerical optimization process for the sizing of an electric vehicle traction drive considering the gear ratio. The results show that the scaling procedure is very accurate, computational very efficient and suitable for the use in machine design optimization.

2

The proposal of a evolutionary strategy generating the data structures on a horizontal tree for test

Żukowicz M., Markiewicz M.

Management Systems in Production Engineering

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2016

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nr 3 (23)

145--149

EN

The aim of the article is to present a mathematical definition of the object model, that is known in computer science as TreeList and to show application of this model for design evolutionary algorithm, that purpose is to generate structures based on this object. The first chapter introduces the reader to the problem of presenting data using the TreeList object. The second chapter describes the problem of testing data structures based on TreeList. The third one shows a mathematical model of the object TreeList and the parameters, used in determining the utility of structures created through this model and in evolutionary strategy, that generates these structures for testing purposes. The last chapter provides a brief summary and plans for future research related to the algorithm presented in the article.

PL

Celem artykułu jest prezentacja definicji matematycznego modelu obiektu, który w informatyce znany jest jako TreeList oraz wykorzystanie tego modelu do zaprojektowania algorytmu ewolucyjnego, którego zadaniem jest generowanie struktur opartych na obiekcie TreeList. Pierwszy rozdział wprowadza czytelnika w problem, jakim jest prezentacja danych za pomocą wspomnianego obiektu TreeList. Drugi rozdział opisuje problem testowania struktur danych opartych o TreeList. Rozdział trzeci natomiast prezentuje matematyczny model obiektu TreeList oraz miary, które można wykorzystać w celu określenia użyteczności struktur utworzonych za pomocą wspomnianych obiektów oraz w strategii ewolucyjnej, która generuje te struktury dla potrzeby ich testowania. Ostatni rozdział zawiera krótkie podsumowanie oraz plany przyszłych badań związanych z zaprezentowanym w artykule algorytmem.

3

A finite-buffer queue with a single vacation policy: An analytical study with evolutionary positioning

Woźniak M., Kempa W. M., Gabryel M., Nowicki R. K.

International Journal of Applied Mathematics and Computer Science

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2014

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Vol. 24, no. 4

887--900

EN

In this paper, application of an evolutionary strategy to positioning a GI/M/1/N-type finite-buffer queueing system with exhaustive service and a single vacation policy is presented. The examined object is modeled by a conditional joint transform of the first busy period, the first idle time and the number of packets completely served during the first busy period. A mathematical model is defined recursively by means of input distributions. In the paper, an analytical study and numerical experiments are presented. A cost optimization problem is solved using an evolutionary strategy for a class of queueing systems described by exponential and Erlang distributions.

4

Applicability of Park transformation for the analysis of transient performance during subsynchronous resonances

Kreischer Ch., Kulig S., Göbel C.

Archives of Electrical Engineering

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2013

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Vol. 62, nr 3

401--415

EN

Long transmission lines have to be compensated to enhance the transport of active power. But a wrong design of the compensation may lead to subsynchronous resonances (SSR). For studies often park equivalent circuits are used. The parameters of the models are often determined analytically or by a three-phase short-circuit test. Models with this parameters give good results for frequencies of 50 Hz and 100 Hz resp. 60 Hz and 120 Hz. But SSR occurs at lower frequencies what arises the question of the reliability of the used models. Therefore in this publication a novel method for the determination of Park equivalent circuit parameters is presented. Herein the parameters are determined form time functions of the currents and the electromagnetic moment of the machine calculated by transient finite-element simulations. This parameters are used for network simulations and compared with the finite-element calculations. Compared to the parameters derived by a three-phase short-circuit a significant better accuracy of simulation results can be achieved by the presented method.

5

Localization in Wireless Sensor Networks Using Heuristic Optimization Techniques

Niewiadomska-Szynkiewicz E., Marks M., Kamola M.

Journal of Telecommunications and Information Technology

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2011

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nr 4

55-64

EN

Many applications of wireless sensor networks (WSN) require information about the geographic location of each sensor node. Devices that form WSN are expected to be remotely deployed in large numbers in a sensing field, and to self-organize to perform sensing and acting task. The goal of localization is to assign geographic coordinates to each device with unknown position in the deployment area. Recently, the popular strategy is to apply optimization algorithms to solve the localization problem. In this paper, we address issues associated with the application of heuristic techniques to accurate localization of nodes in a WSN system. We survey and discuss the location systems based on simulated annealing, genetic algorithms and evolutionary strategies. Finally, we describe and evaluate our methods that combine trilateration and heuristic optimization.

6

Learning stable mutation in (1, lambda)ES evolutionary strategy

Prętki P.

Prace Naukowe Politechniki Warszawskiej. Elektronika

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2007

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z. 160

233-240

EN

In this paper the concept of two-dimensional discrete spectral measure is introduced in the context of its application to real-valued evolutionary strategy (1, lambda)ES. The notion of discrete spectral measure makes it possible to uniquely define a class of multivariate heavy-tailed distributions, that have received more and more attention of evolutionary optimization community, recently. In particular, an adaptation procedure known from the class of estimation of distribution algorithms (EDAs) is proposed. The effectiveness of the evolutionary strategy is tested by means of a set popular benchmark functions.

7

Projektowanie topografii systemów VLSI. Cz. 4. Symulowane wyżarzanie, sieci neuronowe

Nagórny Z., Kos A.

Kwartalnik Elektroniki i Telekomunikacji

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2006

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Vol. 52, z. 4

697-727

PL

Niniejsza praca jest czwartą, ostatnią częścią przeglądu metod rozmieszczania modułów, stosowanych podczas projektowania topografii układów VLSI. Modułem jest fragment systemu wyodrębniony ze względu na pełnioną funkcję. Praca jest poświęcona algorytmowi symulowanego wyżarzania oraz sieciom neuronowych. Przedstawiono dokładny opis algorytmu symulowanego wyżarzania oraz sposób zastosowania algorytmu do rozmieszczania modułów. Programy wykorzystujące algorytm symulowanego wyżarzania zostały szczegółowo opisane. W tym celu scharakteryzowano następujące programy rozmieszczania: TimberWolf, MGP, MPG-MS, VPR. Następnie, opisano sposób zastosowania sieci samoorganizującej się oraz sieci Hopfielda w optymalizacji topografii układów VLSI. Przedstawiono rezultaty rozmieszczania modułów otrzymane z użyciem sieci Hopfielda. Następnie, scharakteryzowano inne metody stosowane podczas rozmieszczania modułów: algorytmy genetyczne, strategie ewolucyjne, schemat rozmieszczanie-planowanie topografii-rozmieszczanie, programy dla układów 3D VLSI oraz sprzętowe metody rozwiązania problemu rozmieszczania modułów. Porównano metody rozmieszczania modułów przedstawione w przeglądzie.

EN

The design process of the VLSI circuits requires the use of computer aided design tools. This paper is the fourth part of the survey of the cell placement techniques for digital VLSI circuits. In this part of the survey, the simulated annealing algorithm and neural networks are presented. An application of the simulated annealing algorithm to the cell placement problem is described. Nowadays the tools used for the cell placement, which utilize the presented algorithms are characterized: TimberWolfSC, TimberWolfMC, MGP, MPG-MS, VPR. Then, applications of neural networks to the cell placement problem are described. A self-organizing network and Hopfield network for the cell placement problem are presented. Some circuit layouts generated by using the Hopfield network are presented. Applications of a genetic algorithm, evolutionary strategy, three-stage placement-floorplanning-placement flow and special purpose hardware for the cell placement are described. Tools used for the 3D VLSI cell placement are characterized. Some conclusions concerning described techniques and tools are presented.

8

Evolution-fuzzy rule based system with parameterized consequences

Czekalski P.

International Journal of Applied Mathematics and Computer Science

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2006

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Vol. 16, no 3

373-385

EN

While using automated learning methods, the lack of accuracy and poor knowledge generalization are both typical problems for a rule-based system obtained on a given data set. This paper introduces a new method capable of generating an accurate rule-based fuzzy inference system with parameterized consequences using an automated, off-line learning process based on multi-phase evolutionary computing and a training data covering algorithm. The presented method consists of the following steps: obtaining an initial set of rules with parameterized consequences using the Michigan approach combined with an evolutionary strategy and a covering algorithm for the training data set; reducing the obtained rule base using a simple genetic algorithm; multi-phase tuning of the fuzzy inference system with parameterized consequences using the Pittsburgh approach and an evolutionary strategy. The paper presents experimental results using popular benchmark data sets regarding system identification and time series prediction, providing a reliable comparison to other learning methods, particularly those based on neuro-fuzzy, clustering and \epsilon-insensitive methods. An examplary fuzzy inference system with parameterized consequences using the Reichenbach implication and the minimum t-norm was implemented to obtain numerical results.

9

Applications of evolutionary strategies in optimal design of mechanical systems

Datoussaid S., Guerlement G., Descamps T.

Foundations of Civil and Environmental Engineering

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2006

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No. 7

35-51

EN

This paper is concerned with the optimization of structural systems. On one hand it concerns the kinematic or dynamic behaviour of multibody systems. On the other hand it concerns the minimum weight desmg of frames according to static and dynamic constraints. The authors first recall the classical form of an optimization problem, whose purpose is to find the set of design variables which minimizes a given objective function while verifying potentialconstraints. After recalling the principal optimization techniques, the evolutionary strategies are presented in detail. They are inspired from the natural evolution: the genes of individuals mutate from generation to generation and the survivings are those being the best fitted to their environment. The analogy with an optimization problem is quite straightforward: a set of design variables can be considered as the genes of an individual and the value of the objective function for this set of design variables represents the fitness for survival of the corresponding individual. Practically, the mutation is performed by modifying the design variables of μ parents, according to a normal distribution with zero as average and gives rise to offsprings whose best μ individuals form the new parent population. The paper gives some indica tions for the choice of the principal parameters or options and explains how to manage the mutation in order to control the speed of convergence. The performances of the evolutionary strategies are then illustrated by three examples: the structural optimization of a two-storey steel frame, the kinematic optimization of a suspension and the dynamic optimization of the comfort of a railway vehicle. Evolutionary strategies, although slower than hill-climbing methods, arc an interesting alternative. They indeed have several advantages: the optimization engine remains completely independent of the simulation one and can be adapted to any field of engineering, they are very robust and converge to global and not local optimal solutions.

10

Strategie ewolucyjne jako uniwersalne narzędzie do rozwiązywania problemów optymalizacyjnych

Gajer M.

Wiadomości Elektrotechniczne

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2005

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nr 6

15--17

PL

Przedstawiono wykorzystanie podstawowych mechanizmów ewolucyjnych w algorytmach genetycznych. Zaprezentowano zastosowanie strategii ewolucyjnej do rozwiązania problemów optymalizacji.

EN

The paper describes using of basie evolutionary mechanisms in genetic algorithms. Using of evolutionary strategy for solving of optimization problems is presented.

11

Heuristic Approaches to the Maximization of the Number of Spanning Trees in Regular Graphs

Sawionek B., Wojciechowski J., Arabas J.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2000

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Vol. 48, nr 4

573-586

EN

The paper deals with a fundamental problem arising in the design of optimal network structures - maximization of the number of spanning trees. To make the problem computationally tractable, we consider a class of regular graphs. The problem is solved with the usage of evolutionary and 2-opt algorithms. The problem-specific genetic operators are introduced. Various experiments with different graphs structures have been performed, the results are reported, and the methods compared. Influence of introducing some preliminary knowledge about the problem on the algorithm effectiveness is studied.