Generating Interpretable Fuzzy Controllers using Particle Swarm Optimization and Genetic Programming

Autonomously training interpretable control strategies, called policies, using pre-existing plant trajectory data is of great interest in industrial applications. Fuzzy controllers have been used in industry for decades as interpretable and efficient system controllers. In this study, we introduce a fuzzy genetic programming (GP) approach called fuzzy GP reinforcement learning (FGPRL) that can select the relevant state features, determine the size of the required fuzzy rule set, and automatically adjust all the controller parameters simultaneously. Each GP individual's fitness is computed using model-based batch reinforcement learning (RL), which first trains a model using available system samples and subsequently performs Monte Carlo rollouts to predict each policy candidate's performance. We compare FGPRL to an extended version of a related method called fuzzy particle swarm reinforcement learning (FPSRL), which uses swarm intelligence to tune the fuzzy policy parameters. Experiments using an industrial benchmark show that FGPRL is able to autonomously learn interpretable fuzzy policies with high control performance.Comment: Accepted at Genetic and Evolutionary Computation Conference 2018 (GECCO '18

Aging, rejuvenation and memory effects in re-entrant ferromagnets

We have studied the slow dynamics of the ferromagnetic phases of the re-entrant CdCr_{2x}In_{2-2x}S_4 system for 0.85<x<=1 by means of low frequency ac susceptibility and magnetization measurements. Experimental procedures widely used in the investigation of the out-of-equilibrium dynamics of spin glasses (such as the x=0.85 compound) have been applied to search for aging, rejuvenation and memory effects, and to test their dependence on the disorder introduced by dilution of the magnetic ions. Whereas the rejuvenation effect is found in all studied samples, the memory effect is clearly enhanced for increasing dilutions. The results support a description of aging in both ferromagnetic and re-entrant spin-glass phases in terms of hierarchical reconformations of domain walls pinned by the disorder.Comment: Service de Physique de l'Etat Condense, DRECAM, DSM, CEA Saclay,91191 Gif sur Yvette Cedex, France, 9 pages, including 7 figures, To appear in Eur. Phys. J. B (2002

On numbers nn dividing the nnth term of a linear recurrence

Here, we give upper and lower bounds on the count of positive integers $n\le x$ dividing the $n$th term of a nondegenerate linearly recurrent sequence with simple roots

Characterization of periodic cavitation in an optical tweezer

Microscopic vapor explosions or cavitation bubbles can be generated periodically in an optical tweezer with a microparticle that partially absorbs at the trapping laser wavelength. In this work we measure the size distribution and the production rate of cavitation bubbles for microparticles with a diameter of 3 $\mu$m using high speed video recording and a fast photodiode. We find that there is a lower bound for the maximum bubble radius $R_{max}\sim 2~\mu$m which can be explained in terms of the microparticle size. More than $94 \%$ of the measured $R_{max}$ are in the range between 2 and 6 $\mu$m, while the same percentage of the measured individual frequencies $f_i$ or production rates are between 10 and 200 Hz. The photodiode signal yields an upper bound for the lifetime of the bubbles, which is at most twice the value predicted by the Rayleigh equation. We also report empirical relations between $R_{max}$, $f_i$ and the bubble lifetimes.Comment: 5 pages, 3 figure

Finding Best Compiler Options for Critical Software Using Parallel Algorithms

The efficiency of a software piece is a key factor for many systems. Real-time programs, critical software, device drivers, kernel OS functions and many other software pieces which are executed thousands or even millions of times per day require a very efficient execution. How this software is built can significantly affect the run time for these programs, since the context is that of compile-once/run-many. In this sense, the optimization flags used during the compilation time are a crucial element for this goal and they could make a big difference in the final execution time. In this paper, we use parallel metaheuristic techniques to automatically decide which optimization flags should be activated during the compilation on a set of benchmarking programs. The using the appropriate flag configuration is a complex combinatorial problem, but our approach is able to adapt the flag tuning to the characteristics of the software, improving the final run times with respect to other spread practicesThis research has been partially funded by the Spanish MINECO and FEDER projects (TIN2014-57341-R (http://moveon.lcc.uma.es), TIN2016-81766-REDT (http://cirti.es), and TIN2017-88213-R (http://6city.lcc.uma.es). It is also funded by Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Aging phenomena in spin glass and ferromagnetic phases: domain growth and wall dynamics

We compare aging in a disordered ferromagnet and in a spin glass, by studying the different phases of a reentrant system. We have measured the relaxation of the low-frequency ac susceptibility, in both the ferromagnetic and spin-glass phases of a CdCr_{1.9}In_{0.1}S_4 sample. A restart of aging processes when the temperature is lowered (`chaos-like' effect) is observed in both phases. The memory of previous aging at a higher temperature can be retrieved upon re-heating, but in the ferromagnetic phase it can rapidly be erased by the growth of ferromagnetic domains. We interpret the behaviour observed in the ferromagnetic phase in terms of a combination of domain growth and pinned wall reconformations, and suggest that aging in spin glasses is dominated by such wall reconformation processes.Comment: SPEC, CEA Saclay, 91191 Gif sur Yvette Cedex, France, to appear in Europhys. Lett. (2000

Promoting a local brand: Assessing the Economic Benefits of the Texas Superstar® and Earth-Kind® Promotion on Place (POP) Program

This paper aims to evaluate consumer’s awareness and willingness-to-pay (WTP) for two ornamental brands in Texas: Texas Superstar® and Earth-Kind®, after a Promotion on Place (POP) Program was developed by the Texas Department of Agriculture (TDA). Consumer’s characteristics that are more likely to influence brand awareness and WTP are identified.Brand recognition, Willingness to pay, Consumer preferences, Ornamentals, Consumer/Household Economics, Marketing,

The percentile residual life up to time t0: ordering and aging properties

Motivated by practical issues, a new stochastic order for random variables is introduced by comparing all their percentile residual life functions until a certain instant. Some interpretations of these stochastic orders are given, and various properties of them are derived. The relationships to other stochastic orders are studied, and also an application in Reliability Theory is described. Finally, we present some characterization results of the decreasing percentile residual life up to time t0 aging notion.Aging notion, Hazard rate, Mean residual life, Percentile residual life, Reliability, Stochastic ordering