Wyniki wyszukiwania - BazTech

1

Optymalizacja dwukryterialna gazowego systemu przesyłowego

Osiadacz Andrzej J., Niccolo Isoli

Gaz, Woda i Technika Sanitarna

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2020

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Nr 4

2--9

PL

W artykule omówiono zagadnienie optymalizacji gazowego systemu przesyłowego przy wykorzystaniu różnych postaci funkcji celu. Zastosowano funkcje skalarne minimalizujące koszty transportu, maksymalizujące akumulację systemu oraz funkcję dwukryterialną szukającą kompromisu między kryteriami skalarnymi. Badania przeprowadzono na rzeczywistych strukturach systemu przesyłowego.

EN

The article discusses the issues of optimizing the gas transmission system using different forms of objective function. Scalar functions were used to minimize operating costs or maximize accumulation and a bi-criteria function trying to find compromise between both of them. Tests were carried out on real transmission system structures.

2

Recommendations as a result of decision evaluations based on reference examples

Kwiatkowski Włodzimierz

Przegląd Teleinformatyczny

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2019

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T. 7, Nr 1-2 (48)

1--23

EN

The problem of evaluation of decisions is considered, which evaluation consists in selecting from the set of possible decisions those that meet the decision-maker's preferences. The added value of solving this problem lies in the reduction of the number of decisions one can choose. Evaluation of decisions is based on their complete characteristics, rather than on a pre-defined quality indicator. The basis for the quality assessment are given pattern examples of decisions made. These are decisions that the decision maker has found to be exemplary or acceptable. They are used as defining his preferences. The methods proposed in this article concern the ordering and clustering of decisions based on their characteristics. The set of decisions selected by an algorithm is interpreted as recommended for the decision maker. Presented solutions can find a variety of applications, for example in investment planning, routing, diagnostics or searching through multimedia databases.

PL

Rozpatrywany jest problem ewaluacji decyzji polegający na wytypowaniu spośród możliwych decyzji tych, które spełniają preferencje decydenta. Użyteczność rozwiązania problemu polega na zredukowaniu liczby możliwych do wyboru decyzji. Ewaluacja decyzji bazuje na ich kompletnych charakterystykach, a nie na wcześniej zdefiniowanym wskaźniku jakości. Podstawą oceny jakości są wzorcowe przykłady decyzji. Są to decyzje, które decydent uznał za doskonałe lub akceptowalne. Wskazane przez decydenta przykłady są wykorzystywane jako określające jego preferencje. Proponowane w artykule metody dotyczą porządkowania i grupowania decyzji na podstawie ich charakterystyk. Wytypowany zbiór decyzji jest interpretowany jako rekomendowany dla decydenta. Przedstawione rozwiązania mogą znaleźć różnorakie zastosowania, np. w planowaniu inwestycji, trasowaniu, diagnostyce czy przeszukiwaniu multimedialnych baz danych.

3

Higher-order conditions for strict local Pareto minima for problems with partial order introduced by a polyhedral cone

Stasiak A.

Journal of Applied Analysis

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2018

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Vol. 24, nr 1

45--54

EN

Using the definitions of μ-th order lower and upper directional derivatives of vector-valued functions, introduced in Rahmo and Studniarski (J. Math. Anal. Appl. 393 (2012), 212-221), we provide some necessary and sufficient conditions for strict local Pareto minimizers of order μ for optimization problems where the partial order is introduced by a pointed polyhedral cone with non-empty interior.

4

Strukturalna optymalizacja wektorowa narzędzia robota medycznego z wykorzystaniem metody elementów skończonych

Ilewicz G., Nawrat Z.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2016

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Vol. 22, nr 4

234--244

PL

Praca przybliża analizy strukturalne z wykorzystaniem algorytmu metody elementów skończonych, która a priori daje prawidłowe wyniki dla układów o skomplikowanej geometrii, dla której trudno jest uzyskać rozwiązanie analityczne lub dla której przeprowadzenie testów fizycznych jest utrudnione. Eksperymenty numeryczne zostały przeprowadzone dla narzędzia robota kardiochirurgicznego Robin Heart 1, który został przetestowany podczas operacji na zwierzętach. W artykule pokazano wyniki analizy deformacji, częstotliwości drgań własnych oraz optymalizację wektorową mającą na celu określenie ekstremum w oparciu o algorytm genetyczny. Wykorzystano również metodę powierzchni odpowiedzi, globalny front Pareto i metodę elementów skończonych. Zaprezentowany model optymalizacji wielokryteralnej umożliwia uzyskiwanie struktury o minimalnej masie i maksymalnej sztywności oraz odstrajanie układu od częstotliwości bliskich rezonansowym. Przy minimalnym wzroście masy, co skutkuje minimalizacją amplitudy drgań podczas ruchu narzędzia. Celem pracy jest wyjaśnienie zjawiska rezonansu dla wyznaczonych częstotliwości drgań własnych narzędzia do serwisowania sztucznego narządu i wektorów własnych, które przedstawiają kształty deformacji przy pojawieniu się tego negatywnego zjawiska.

EN

The work explains structural analysis using algorithm of finite element method, which gives a priori correct results for systems with complicate geometry for which it is difficult to obtain analytical solution or when conducting physical tests is hampered. Numerical experiments were performed for endoscopic tool of cardiosurgical robot Robin Heart 1, which was tested during the operating experiment on animals. The article shows the results of the analysis of deformation, natural frequency of vibrations, and vectorial optimization aiming at calculations of extremum on the basis of genetic algorithm. Response surface method, global Pareto front, and finite element method were also used. The presented model of vectorial optimization allows to obtain the structure with minimal mass and maximal stiffness and tuning away from frequency that are close to resonant frequency. At minimum mass increase which results in minimizing the amplitude of vibration during movement of the tool. The aim of the work is also to explain of the phenomenon of resonance for the designated vibration natural frequencies of the tool for servicing an artificial organ and eigenvectors which show shapes of deformation as a result of this negative phenomenon.

5

C^1'1 vector optimization problems and Riemann derivatives

Ginchev I., Guerraggio A., Rocca M.

Control and Cybernetics

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2004

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Vol. 33, no 2

259-273

EN

In this paper we introduce a generalized second-order Riemann-type derivative for C^1'1 vector functions and use it to establish necessary and sufficient optimality conditions for vector optimization problems. We show that, these conditions are stronger than those obtained by means of the second-order subdinerential in Clarke sense considered in Guerraggio, Luc (2001) and also to some extent than those obtained in Guerraggio, Luc, Minh (2001).

6

Application of multiple criteria evolutionary algorithms to vector optimisation, decision support and reference point approaches

Szczepański M., Wierzbicki A. P.

Journal of Telecommunications and Information Technology

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2003

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nr 3

16-33

EN

Multiple criteria evolutionary algorithms, being essentially parallel in their character, are a natural instrument of finding a representation of entire Pareto set (set of solutions and outcomes non-dominated in criteria space) for vector optimisation problems. However, it is well known that Pareto sets for problems with more than two criteria might become complicated and their representation very time-consuming. Thus, the application of such algorithms is essentially limited to bi-criteria problems or to vector optimisation problems with more criteria but of simple structure. Even in such cases, there are problems related to various important aspects of vector optimisation, such as the uniformity of representation of Pareto set, stopping tests or the accuracy of representing Pareto set, that are not fully covered by the broad literature on evolutionary algorithms in vector optimisation. These problems and related computational tests and experience are discussed in the paper. In order to apply evolutionary algorithms for decision support, it would be helpful to use them in an interactive mode. However, evolutionary algorithms are in their essence global and of batch type. Nevertheless, it is possible to introduce interactive aspects to evolutionary algorithms by focusing them on a part of Pareto set. The results of experimental tests of such modifications of evolutionary algorithms for vector optimisation are presented in the paper. Another issue related to vector optimisation problems with more than two criteria is the computational difficulty of estimating nadir points of Pareto set. The paper describes the use of diverse variants of evolutionary algorithms to the estimation of nadir points, together with experimental evidence.

7

Order-Lipschitzian properties of multifunctions with applications to stability of efficient points

Bednarczuk E. M.

Control and Cybernetics

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2003

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Vol. 32, no 3

491-502

EN

We define order-Lipschitzian properties of multifunctions and we investigate local upper order-lipschitzness and order-calmness of efficient points of a set depending upon a parameter.

8

Hoelder-like properties of minimal points in vector optimization

Bednarczuk E.

Control and Cybernetics

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2002

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Vol. 31, no 3

423-438

EN

We derive conditions for Hoelder calmness of minimal points of a given set, as a function of a parameter appearing in the description of the set. Different criteria are proved depending on whwther the ordering cone has a nonempty interior or not.

9

Optimality conditions and a classification of duality schemes in vector optimization

El Ghali B.

Control and Cybernetics

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2000

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Vol. 29, no 4

839-860

EN

Vector minimization of a relation F valued in an ordered vector space under a constraint A consists in finding x[0] belongs to A, w[0] belongs to Fx[0] such that w[0] is minimal in FA. To a family of vector minimization problems minimize[x belongs to X] F(x, y), y [belongs to] Y, one associates a Lagrange relation [L(x, [xi], y[0]) = union of sets y belongs to Y(F(x, y)-xi(y)+(y[0]))] where [xi] belongs to an arbitrary class [Xi] of mappings. For this type of problem, there exist several notions of solutions. Some useful characterizations of existential solutions are established and, consequently, some necessary conditions of optimality are derived. One result of intermediate duality is proved with the aid of the scalarization theory. Existence theorems for existential solutions are given and a comparison of several exact duality schemes is established, more precisely in the convex case it is shown that the majority of exact duality schemes can be obtained from one result of S. Dolecki and C. Malivert.

10

Contingent epiderivative and its applications to set-valued optimization

Bednarczuk E., Song W.

Control and Cybernetics

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1998

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Vol. 27, no 3

375-386

EN

In the present paper we give an alternative definition of contingent epiderivative for a set-valued map. We use our concept of contingent epiderivative to formulate necessary and/ or sufficient optimality conditions for a set-valued optimization problem and to study sensivity of a family of parametrized vector optimization problems.