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Wyszukujesz frazę "Optimization" wg kryterium: Temat


Tytuł:
Structural weight minimization of high speed vehicle-passenger catamaran by genetic algorithm
Autorzy:
Sekulski, Z.
Tematy:
ship structure
optimization
topology optimization
sizing optimization
genetic algorithm
Pokaż więcej
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:
https://bibliotekanauki.pl/articles/258678.pdf  Link otwiera się w nowym oknie
Opis:
Reduction of hull structural weight is the most important aim in the design of many ship types. But the ability of designers to produce optimal designs of ship structures is severely limited by the calculation techniques available for this task. Complete definition of the optimal structural design requires formulation of size-topology-shape-material optimization task unifying optimization problems from four areas and effective solution of the problem. So far a significant progress towards solution of this problem has not been achieved. In other hand in recent years attempts have been made to apply genetic algorithm (GA) optimization techniques to design of ship structures. An objective of the paper was to create a computer code and investigate a possibility of simultaneous optimization of both topology and scantlings of structural elements of large spacial sections of ships using GA. In the paper GA is applied to solve the problem of structural weight minimisation of a high speed vehicle-passenger catamaran with several design variables as dimensions of the plate thickness, longitudinal stiffeners and transverse frames and spacing between longitudinals and transversal members. Results of numerical experiments obtained using the code are presented. They shows that GA can be an efficient optimization tool for simultaneous design of topology and sizing high speed craft structures.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bainite transformation time model optimization for Austempered Ductile Iron with the use of heuristic algorithms
Autorzy:
Olejarczyk-Wożeńska, Izabela
Opaliński, Andrzej
Mrzygłód, Barbara
Regulski, Krzysztof
Kurowski, Wojciech
Tematy:
heuristic optimization
bainite
ADI
Particle Swarm Optimization
Evolutionary Optimization Algorithm
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Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:
https://bibliotekanauki.pl/articles/29520068.pdf  Link otwiera się w nowym oknie
Opis:
The paper presents the application of heuristic optimization methods in identifying the parameters of a model for bainite transformation time in ADI (Austempered Ductile Iron). Two algorithms were selected for parameter optimization – Particle Swarm Optimization and Evolutionary Optimization Algorithm. The assumption of the optimization process was to obtain the smallest normalized mean square error (objective function) between the time calculated on the basis of the identified parameters and the time derived from the experiment. As part of the research, an analysis was also made in terms of the effectiveness of selected methods, and the best optimization strategies for the problem to be solved were selected on their basis.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measuring diversity of socio-cognitively inspired ACO search
Autorzy:
Świderska, Ewelina
Lenaerts, Tom
Samson, Dana
Łasisz, Jakub
Byrski, Aleksander
Kisiel-Dorohinicki, Marek
Nowé, Ann
Indurkhya, Bipin
Wydawca:
Springer
Opis:
In our recent research, we implemented an enhancement of Ant Colony Optimization incorporating the socio-cognitive dimension of perspective taking. Our initial results suggested that increasing the diversity of ant population - introducing different pheromones, different species and dedicated inter-species relations - yielded better results. In this paper, we explore the diversity issue by introducing novel diversity measurement strategies for ACO. Based on these strategies we compare both classic ACO and its socio-cognitive variation.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Composite semi-infinite optimization
Autorzy:
Dentcheva, D.
Ruszczyński, A.
Tematy:
semi-infinite optimization
nonsmooth optimization
composite optimization
stochastic programming
stochastic dominance
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Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Powiązania:
https://bibliotekanauki.pl/articles/970266.pdf  Link otwiera się w nowym oknie
Opis:
We consider a semi-infinite optimization problem in Banach spaces, where both the objective functional and the constraint operator are compositions of convex nonsmooth mappings and differentiable mappings. We derive necessary optimality conditions for these problems. Finally, we apply these results to non-convex stochastic optimization problems with stochastic dominance constraints, generalizing earlier results.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hybrid optimization process applied to tuning of Dynamic Matrix Control: atudy case with DC motor
Autorzy:
Carvalho, D. F. de
Ganzaroli, C. A.
Couto, L. do
Dias, R. N. H. M.
Calixto, W. P.
Tematy:
predictive control
deterministic optimization
heuristic optimization
hybrid optimization
DC motor
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Wydawca:
EEEIC International Barbara Leonowicz Szabłowska
Powiązania:
https://bibliotekanauki.pl/articles/136171.pdf  Link otwiera się w nowym oknie
Opis:
This paper presents study about Dynamic Matrix Control (DMC) controller applied to speed control of DC motor. DMC controller parameters (prediction horizon, control horizon and damping rate of reference) are obtained through optimization methods employing heuristic, deterministic and hybrid strategies. The use of advanced control technique combined with using of optimization methods aims to achieve highly efficient control, reducing the transient state period and variations in steady state. These methods were applied on a simulation model in order to verify which one provides better control results.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hierarchical genetic computation in optimal design
Hierarchiczne obliczenia genetyczne w projektowaniu optymalnym
Autorzy:
Kołodziej, J.
Schaefer, R.
Paszyńska, A.
Tematy:
hierarchical genetic optimization
graph encoding
shape optimization
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Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:
https://bibliotekanauki.pl/articles/281989.pdf  Link otwiera się w nowym oknie
Opis:
The paper presents two examples of genetic hierarchic global optimization methods. They are two different goals of introducing hierarchy into the computational model: to perform the multi-scale search with the adapted accuracy and to better express the structure geometry in the optimal shape design. Results of the formal analysis and simple computational examples are also attached.
Praca przedstawia dwa przykłady hierarchicznych, genetycznych metod optymalizacji. Sklasyfikowano dwa główne powody wprowadzenia hierarchii do modelu obliczeniowego: dla uzyskania wieloskalowego przeszukania z adaptowaną dokładnością oraz dla lepszego odwzorowania kształtu konstrukcji w zadaniach optymalnego projektowania kształtu. Zamieszczono rezultaty formalnej analizy proponowanych strategii oraz proste przykłady obliczeniowe.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research of influence of calculation precision on the effectiveness of stochastic optimization methods
Autorzy:
Cegielski, M.
Stakhiv, P.
Kozak, Yu.
Tematy:
stochastic optimization methods
graphics processors
optimization speed
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Wydawca:
Polska Akademia Nauk. Oddział w Lublinie PAN
Powiązania:
https://bibliotekanauki.pl/articles/410742.pdf  Link otwiera się w nowym oknie
Opis:
This paper describes the influence of the varying computation precision when performing calculations using the optimizing algorithms. A comparative analysis of the computation speed and obtained result accuracy of the Rastrigin’s direct cone method with adapting of the step length and the angle of the cone's disclosure for varying precision was performed. It is shown that the speed of the optimization algorithm practically does not depend on used computation precision. The difference is observed only in accuracy of the obtained results. The investigation of optimizing algorithms behavior under the presence of noise, in particular due to rounding errors was conducted. It is shown that the optimizing algorithm under research becomes unsuitable after some noise level. Characteristics of the optimization algorithm during calculations with a single precision proved to be better then the characteristics of the algorithm when performing calculations with double precision. The analysis of possibilities of the effective graphics processors (GPU) application in order to conduct optimization was carried out. In particular, the difference in the speed of the GPU when performing calculations with a single and double precision was considered. To ensure the efficiency of calculations based on optimization algorithms, it is recommended to carry out calculations with the use of single precision, and increase the calculation precision in case of impossibility to achieve the desired accuracy of the result. There is considering the significantly higher performance of graphics processors when doing calculations with a single precision in comparison with calculations with double precision it is expedient to use a single calculation precision when graphic processors are used to solve considered problem. Double precision can be used if it is difficult to get sufficiently correct solution by single precision calculations. The results of numerical experiments confirm that the use of lower precision to perform optimization for macromodels creation has a slight influence on the speed of achieving of predetermined optimization accuracy.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Graph based discrete optimization in structural dynamics
Autorzy:
Blachowski, B.
Gutkowski, W.
Tematy:
discrete structural optimization
combinatorial optimization
structural dynamics
stochastic loading
problem oriented optimization
graphs
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Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/200069.pdf  Link otwiera się w nowym oknie
Opis:
In this study, a relatively simple method of discrete structural optimization with dynamic loads is presented. It is based on a tree graph, representing discrete values of the structural weight. In practical design, the number of such values may be very large. This is because they are equal to the combination numbers, arising from numbers of structural members and prefabricated elements. The starting point of the method is the weight obtained from continuous optimization, which is assumed to be the lower bound of all possible discrete weights. Applying the graph, it is possible to find a set of weights close to the continuous solution. The smallest of these values, fulfilling constraints, is assumed to be the discrete minimum weight solution. Constraints can be imposed on stresses, displacements and accelerations. The short outline of the method is presented in Sec. 2. The idea of discrete structural optimization by means of graphs. The knowledge needed to apply the method is limited to the FEM and graph representation. The paper is illustrated with two examples. The first one deals with a transmission tower subjected to stochastic wind loading. The second one with a composite floor subjected to deterministic dynamic forces, coming from the synchronized crowd activities, like dance or aerobic.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative Study of PSO and CMA-ES Algorithms on Black-box Optimization Benchmarks
Autorzy:
Szynkiewicz, P.
Tematy:
benchmarking
black-box optimization
CMA-ES
global optimization
PSO
stochastic optimization
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Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Powiązania:
https://bibliotekanauki.pl/articles/307566.pdf  Link otwiera się w nowym oknie
Opis:
Numerous practical engineering applications can be formulated as non-convex, non-smooth, multi-modal and ill-conditioned optimization problems. Classical, deterministic algorithms require an enormous computational effort, which tends to fail as the problem size and its complexity increase, which is often the case. On the other hand, stochastic, biologically-inspired techniques, designed for global optimum calculation, frequently prove successful when applied to real life computational problems. While the area of bio-inspired algorithms (BIAs) is still relatively young, it is undergoing continuous, rapid development. Selection and tuning of the appropriate optimization solver for a particular task can be challenging and requires expert knowledge of the methods to be considered. Comparing the performance of viable candidates against a defined test bed environment can help in solving such dilemmas. This paper presents the benchmark results of two biologically inspired algorithms: covariance matrix adaptation evolution strategy (CMA-ES) and two variants of particle swarm optimization (PSO). COCO (COmparing Continuous Optimizers) – a platform for systematic and sound comparisons of real-parameter global optimization solvers was used to evaluate the performance of CMA-ES and PSO methods. Particular attention was paid to the effciency and scalability of both techniques.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Raport Badawczy = Research Report ; RB/50/2003
Methods review for solving inverse optimization problems
Autorzy:
Gola, Magdalena
Wydawca:
Instytut Badań Systemowych. Polska Akademia Nauk
Systems Research Institute. Polish Academy of Sciences
Powiązania:
Raport Badawczy = Research Report
Opis:
Bibliografia s. 18-20
This paper presents review of methods for solving various inverse combinatorial optimization problems, for example: inverse shortest path problem, inverse spanning tree problem, inverse minimum cut problem, etc., as well as some general methods for solving inverse problems.
20 pages ; 21 cm
20 stron ; 21 cm
Bibliography p. 18-20
Dostawca treści:
RCIN - Repozytorium Cyfrowe Instytutów Naukowych
Książka

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