53,405 research outputs found
State Transition Algorithm
In terms of the concepts of state and state transition, a new heuristic
random search algorithm named state transition algorithm is proposed. For
continuous function optimization problems, four special transformation
operators called rotation, translation, expansion and axesion are designed.
Adjusting measures of the transformations are mainly studied to keep the
balance of exploration and exploitation. Convergence analysis is also discussed
about the algorithm based on random search theory. In the meanwhile, to
strengthen the search ability in high dimensional space, communication strategy
is introduced into the basic algorithm and intermittent exchange is presented
to prevent premature convergence. Finally, experiments are carried out for the
algorithms. With 10 common benchmark unconstrained continuous functions used to
test the performance, the results show that state transition algorithms are
promising algorithms due to their good global search capability and convergence
property when compared with some popular algorithms.Comment: 18 pages, 28 figure
Studying Parallel Evolutionary Algorithms: The cellular Programming Case
Parallel evolutionary algorithms, studied to some extent over the past few years, have proven empirically worthwhile—though there seems to be lacking a better understanding of their workings. In this paper we concentrate on cellular (fine-grained) models, presenting a number of statistical measures, both at the genotypic and phenotypic levels. We demonstrate the application and utility of these measures on a specific example, that of the cellular programming evolutionary algorithm, when used to evolve solutions to a hard problem in the cellular-automata domain, known as synchronization
Constructing Parsimonious Analytic Models for Dynamic Systems via Symbolic Regression
Developing mathematical models of dynamic systems is central to many
disciplines of engineering and science. Models facilitate simulations, analysis
of the system's behavior, decision making and design of automatic control
algorithms. Even inherently model-free control techniques such as reinforcement
learning (RL) have been shown to benefit from the use of models, typically
learned online. Any model construction method must address the tradeoff between
the accuracy of the model and its complexity, which is difficult to strike. In
this paper, we propose to employ symbolic regression (SR) to construct
parsimonious process models described by analytic equations. We have equipped
our method with two different state-of-the-art SR algorithms which
automatically search for equations that fit the measured data: Single Node
Genetic Programming (SNGP) and Multi-Gene Genetic Programming (MGGP). In
addition to the standard problem formulation in the state-space domain, we show
how the method can also be applied to input-output models of the NARX
(nonlinear autoregressive with exogenous input) type. We present the approach
on three simulated examples with up to 14-dimensional state space: an inverted
pendulum, a mobile robot, and a bipedal walking robot. A comparison with deep
neural networks and local linear regression shows that SR in most cases
outperforms these commonly used alternative methods. We demonstrate on a real
pendulum system that the analytic model found enables a RL controller to
successfully perform the swing-up task, based on a model constructed from only
100 data samples
Multiobjective optimization of electromagnetic structures based on self-organizing migration
Práce se zabĂ˝vá popisem novĂ©ho stochastickĂ©ho vĂcekriteriálnĂho optimalizaÄŤnĂho algoritmu MOSOMA (Multiobjective Self-Organizing Migrating Algorithm). Je zde ukázáno, Ĺľe algoritmus je schopen Ĺ™ešit nejrĹŻznÄ›jšà typy optimalizaÄŤnĂch Ăşloh (s jakĂ˝mkoli poÄŤtem kritĂ©riĂ, s i bez omezujĂcĂch podmĂnek, se spojitĂ˝m i diskrĂ©tnĂm stavovĂ˝m prostorem). VĂ˝sledky algoritmu jsou srovnány s dalšĂmi běžnÄ› pouĹľĂvanĂ˝mi metodami pro vĂcekriteriálnĂ optimalizaci na velkĂ© sadÄ› testovacĂch Ăşloh. Uvedli jsme novou techniku pro vĂ˝poÄŤet metriky rozprostĹ™enĂ (spread) zaloĹľenĂ© na hledánĂ minimálnĂ kostry grafu (Minimum Spanning Tree) pro problĂ©my majĂcĂ vĂce neĹľ dvÄ› kritĂ©ria. DoporuÄŤenĂ© hodnoty pro parametry Ĺ™ĂdĂcĂ bÄ›h algoritmu byly urÄŤeny na základÄ› vĂ˝sledkĹŻ jejich citlivostnĂ analĂ˝zy. Algoritmus MOSOMA je dále ĂşspěšnÄ› pouĹľit pro Ĺ™ešenĂ rĹŻznĂ˝ch návrhovĂ˝ch Ăşloh z oblasti elektromagnetismu (návrh Yagi-Uda antĂ©ny a dielektrickĂ˝ch filtrĹŻ, adaptivnĂ Ĺ™ĂzenĂ vyzaĹ™ovanĂ©ho svazku v ÄŤasovĂ© oblasti…).This thesis describes a novel stochastic multi-objective optimization algorithm called MOSOMA (Multi-Objective Self-Organizing Migrating Algorithm). It is shown that MOSOMA is able to solve various types of multi-objective optimization problems (with any number of objectives, unconstrained or constrained problems, with continuous or discrete decision space). The efficiency of MOSOMA is compared with other commonly used optimization techniques on a large suite of test problems. The new procedure based on finding of minimum spanning tree for computing the spread metric for problems with more than two objectives is proposed. Recommended values of parameters controlling the run of MOSOMA are derived according to their sensitivity analysis. The ability of MOSOMA to solve real-life problems from electromagnetics is shown in a few examples (Yagi-Uda and dielectric filters design, adaptive beam forming in time domain…).
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