Gabriel Winter

• Full Professor
• University of Las Palmas de Gran Canaria

The degradation rate of polycaprolactone (PCL) is a key issue when using this material in Tissue Engineering or eco-friendly packaging sectors. Although different PCL-based composite materials have been suggested in the literature and extensively tested in terms of processability by material extrusion additive manufacturing, little attention has be...

Game-theory based Nash–evolutionary algorithms are efficient to speed-up and parallelize the optimum design procedure. They have been applied in several fields of engineering and sciences, mainly, in aeronautical and structural engineering. The influence of the search space player territory has been shown as having an important role in the algorith...

A general review of game-theory based evolutionary algorithms (EAs) is presented in this study. Nash equilibrium, Stackelberg game and Pareto optimality are considered, as game-theoretical basis of the evolutionary algorithm design, and also, as problems solved by evolutionary computation. Applications of game-theory based EAs in computational engi...

The aim of this paper is to characterize two HPGe gamma-ray detectors used in two different laboratories for environmental radioactivity measurements, so as to perform efficiency calibrations by means of Monte Carlo Simulation. To achieve such an aim, methodologies developed in previous papers have been applied, based on the automatic optimization...

In this work, we have developed a computational methodology for characterizing HPGe detectors by implementing in parallel a multi-objective evolutionary algorithm, together with a Monte Carlo simulation code. The evolutionary algorithm is used for searching the geometrical parameters of a model of detector by minimizing the differences between the...

The application of cellular structures in additive manufactured parts combined with lightweight optimisation has an enormous potential, reducing weight, production time and cost. This paper presents a new method based on design of experiments, metamodels and genetic algorithms (combined with Computer Aided Design and Finite Element Method tools) to...

The use of evolutionary algorithms has been enhanced in recent years for solving real engineering problems, where the requirements of intense computational calculations are needed, especially when computational engineering simulations are involved (use of finite element method, boundary element method, etc). The coupling of game-theory concepts in...

In this paper we deal with solving inverse problems in structural engineering (both the reconstruction inverse problem and the fully stressed design problem are considered). We apply a game-theory based Nash-evolutionary algorithm and compare it with the standard panmictic evolutionary algorithm. The procedure performance is analyzed on a ten bar s...

This paper reviews the combination of Artificial Neural Networks (ANN) and Evolutionary Optimisation (EO) to solve challenging problems for the academia and the industry. Both methodologies has been mixed in several ways in the last decade with more or less degree of success, but most of the contributions can be classified into the two following gr...

The determination in a sample of the activity concentration of a specific radionuclide by gamma spectrometry needs to know the full energy peak efficiency (FEPE) for the energy of interest. The difficulties related to the experimental calibration make it advisable to have alternative methods for FEPE determination, such as the simulation of the tra...

Additive manufacturing (AM) has become in a competitive method for short series production and high flexibility applications even for functional parts. Few constraints in the manufacturing process involve a great design freedom, allowing minimization of weight by using internal cellular and lattice structures, while minimal mechanical requirements...

The optimization structural design problems of Fully Stressed Design (FSD) and Minimum Constrained Weight (MCW) are compared in this work in a simple truss test case with discrete cross-section type bar sizing, where both optimum designs are coincident. An analysis of the whole search space is included, and the optimization behaviour of evolutionar...

Historical data of electricity demand in La Palma island (Spain) were collected and electricity demand estimates conducted by different organizations were sought. Some factors that could affect these data were studied and its predictions by the next years were looked for. The idea was to use these factors as explanatory variables in order to predic...

In this paper some numerical simulations of the Navier-Stokes Equations (NSE) to test the novel NS-α and NS-ω turbulence models [1, , which conserve energy, enstrophy, and helicity, are presented. These algorithms verify more conservation properties than other implementations of the NSE, however their rotational form [ makes the scaling study of th...

This paper proposes the incorporation of engineering knowledge through both (a) advanced state-of-the-art preference handling decision-making tools integrated in multiobjective evolutionary algorithms and (b) engineering knowledge-based variance-reduction simulation as enhancing tools for the robust optimum design of structural frames taking uncert...

This paper is concerned with the influence of the codification type on the optimization of frame structures for constrained minimum weight, when using discrete variables: cross-section types corresponding to standard profiles. Three different codifications are compared: standard binary, standard reflected gray, and other binary codification with a...

An optimization methodology to evaluate simultaneously optimum designs of multiple slope height values with their corresponding factors of safety is proposed in this paper when considering the problem of slope stability. Limit equilibrium methods and evolutionary computation are used as analysis and optimization tools, respectively. The slip surfac...

Molecular dynamics (MD) simulations are carried out on a system of rigid or flexible water molecules at a series of temperatures between 273 and 368 K. Collective transport coefficients, such as shear and bulk viscosities are calculated, and their behavior is systematically investigated as a function of flexibility and temperature. It is found that...

Gran Canaria is one of the seven Canary Islands, located near Morocco Shore, this position offers a significant renewable energy potential to supply local and tourist population with clean energy. The island is rich in wind and solar resources; it has some wind farms with more of 4000 hours equivalent per year. It has an Energy Plan that provides f...

Considering uncertainties in engineering optimum design is often a requirement. Here, the use of the deterministic optimum design as the reference point in g-dominance is proposed. The multiobjective optimum robust design in a structural engineering test case where uncertainties in the external loads are taken into account is proposed as applicatio...

Pressure autocorrelation functions of two models, SPC/E and SPC/Fw, of pure liquid water are presented. Periodic boundary condition simulations, in the microcanonical ensemble (NVE), of 256 molecules at room temperature are accomplished for both models. Green-Kubo relations are used over the stress tensor time series to extract viscosity properties...

Structural frames robust optimum design under uncertain loads is handled simultaneously minimizing the constrained mass (adding structural mass and constraint average distribution), as well as the constraint violation distribution standard deviation, using the non-dominated sorting genetic algorithm NSGA-II. The consideration of external loads as r...

Platea 4D (Plataforma de Explotación y Análisis de Información Geotemporal) es un proyecto permanente de I+D+i consistente en una plataforma software de ayuda a la toma de decisiones y planificación para grandes emergencias tales como: sucesos contaminantes del medio natural, accidentes con sustancias peligrosas, fenómenos meteorológicos adversos,...

The optimum shape design of Y-noise barriers is carried out using single and multi-objective evolutionary algorithms and the Boundary Element Method (BEM). Reduction of noise impact efficiency (using the insertion loss-IL-magnitude) and cost of the barrier (using its total length magnitude) are considered. A two-dimensional problem of sound propaga...

Every day many kilometres of European highways are blocked by traffic jams. Congestion on roads and at airports adds the EU's fuel bill with a corresponding rise in pollution levels. In short, our present patterns of transport growth are unsustainable. One way of easing road congestion is to develop the efficient end-to-end movement of goods usin...

In this work we propose a Flexible and Parallel Evolutionary Computation to solve a problem of Aeronautic interest, which is the non-linear full potential flow problem inside a nozzle. As the target to verify a numerical scheme for nodal points is equivalent to minimize a corresponding objective function, our methodology consists in using Evolution...

Multiobjective shape design of acoustic attenuation barriers is handled using a boundary element method modeling and evolutionary algorithms. Noise barriers are widely used for environmental protection near population nucleus in order to reduce the noise impact. The minimization of the acoustic pressure and the minimization of the cost of the barri...

A new integrated system with the capacity to help minimize the coastal environmental impacts when a pollutant load is discharged into the sea, in particular oil spills, is presented. The system, named SAMM, integrates simulation models (oil spills, dumping of sewage, brine, etc.) and risk assessment tools for decision-making in emergency situations...

Molecular dynamics simulations were carried out for liquid water in the NVE ensemble for calculating shear and bulk viscosities. We used two different intermolecular potential functions for the water dimer: the empirical SPCE model and the ab initio NCC one. The results obtained are compared with the available experimental values, and show that for...

A new integrated system with the capacity to help minimize coastal environmental impacts when a pollutant load is discharged into the sea (particularly oil spills) is presented. The system (SAMM) integrated simulation models (oil spills sewage dumping, brine, etc.) and risk assessment tools for decision making in emergency situations so as to minim...

Without Abstract

Considering evolutionary multiobjective algorithms for improving single objective optimization problems is focused in this work on introducing the concept of helper objectives in a computational mechanics problem: the constrained mass minimization in real discrete frame bar structures optimum design. The number of different cross-section types of t...

Shape optimum design of M-shaped noise barriers is carried out using BEM for modelling and evolutionary algorithms for optimization. The sound level is calculated being known: The source position, the receptor position, the barrier shape, and the sound frequency. The fitness function to minimize is the sum of squared differences corresponding to th...

The chapter presents a methodology that uses evolutionary algorithms to obtain fluid velocities for potential flows inside a nozzle. A genetic algorithm with real encoding which, with the technique of partial sampling of the solution nodes, presents a number of advantages over other evolutionary algorithms is proposed in the chapter. These include...

Controlled elitism in NSGAII is analysed, applied to a multiobjective frame optimisation problem with discrete modelling. Influence of various mutation rates is considered. A double minimization is handled: constrained weight and number of different cross section types. The comparative statistical results of the test case show a convergence study d...

We present a methodology that attempts to help spill decision responders select appropriate response options to minimize coastal environmental impacts when a tanker leaks oil into the sea. For example, which direction should the tanker head for – towards the open sea or a coastal area where the oil slick can be concentrated and picked up more easil...

The multiobjective or multicriteria optimum design of structural trusses is handled in this paper. A double minimization is taken into account: constrained mass and number of different cross-section types. The first fitness function, the constrained mass, considers constraints in terms of stresses, buckling effect and displacements of certain nodes...

Considering evolutionary multiobjective algorithms for improving single objective optimization problems is focused in this work on introducing the concept of helper objectives in a computational mechanics problem: the constrained mass minimization in real discrete frame bar structures optimum design. The number of different cross-section types of t...

Structural design optimization has been applied, in many structural types, including trusses and frames, mainly oriented to the mass minimization. An additional consideration is the sensitivity of these obtained optimum designs to load variations. Striving after a null constraint violation, even under this possible load variation, simultaneously wi...

Evolutionary algorithms have been widely used for Shape Design Optimization. It is a problem handled in many fields of science and engineering, e.g., aeronautics or solid mechanics. In this work we propose the application of this methodology based on evolutionary algorithms, to the shape design of a noise barrier. Noise Barriers are widely used for...

Parallel CFD 2004, the sixteenth international conference on Parallel Computational Fluid Dynamics and other modern scientific domains, has been held since May 24th till May 27th, 2004 in Las Palmas de Gran Canaria, Spain. The specialized, high-level Parallel CFD conferences are organised on travelling locations all over the world, yearly because o...

A comparative study of the use of Gray coding in multicriteria evolutionary optimisation is performed using the SPEA2 and NSGAII algorithms and applied to a frame structural optimisation problem. A double minimization is handled: constrained mass and number of different cross-section types. Influence of various mutation rates is considered. The com...

Since it has currently became essential to design more efficient and robust alternative techniques to solve hard optimisation problems in industry or science, and of easy use for practitioners, here a new way of developing simple Artificial Intelligence based Evolutionary Algorithms will be introduced. Our evolutionary computational implementation...

This chapter proposes a solution to a state constrained optimal control problem with parallel implementations of an intelligent optimization system based on evolutionary self-learning named flexible evolution agent (FEA). The agent has a dynamic structure of operators (DSO), enlargement of the genetic code (EGC) of each candidate solution, and uses...

The constrained minimum-mass problem of middle-size frames is taken into account, for both continuous and discrete cases with ideal (without buckling effect and own gravitational load) and real (with both) models, comparing three strategies of evolutionary algorithms. Some proposals to obtain appropriate results in middle-sized frames are exposed:...

Combinations of mathematical models with data at particular points from observational networks are required in order to generate physically consistent wind fields and atmospheric pollutant distributions. We describe a methodology used to evaluate the modifications to wind flow and pollutant dispersion, mainly caused by the interaction of the air fl...

This paper attempts to present a summarized survey in the field of Parallel Evolutionary Algorithms (PEAs), trying to highlight the most relevent aspects in the design and implementation of each class of PEAs. A review of the most advanced research activities on this field is presented. New tools for new challenges of industry and society, which ar...

Elitism has been proved to improve the behaviour of multiobjective evolutionary algorithms. Ways to favour the increment of diversity in the population are recently proposed. Duplicate elimination is showed as an operator that can increase the performance of elitist algorithms. A statistical study of the interaction of this operator with the elitis...

Multiobjective evolutionary methods have acquired relevance because of the lack of disadvantages that the classic multiobjective methods have. They allow locating the whole Pareto frontier in a single run—depending on the value of fitness. With this frontier, the designer selects the solution that better fits into one's requirements. This chapter b...

A new procedure to solve some fluid problems formulated in elliptical partial differential equations is presented. A Genetic Algorithm with a dynamical encoding and a partial grid sampling is proposed for it as the advantages of solving the problem without using all grid nodes at the same time, and of adjusting step grid, without increasing the com...

In this paper an alternative design for the internal structure of Evolutionary Algorithms is presented and a first implementation of such structure is tested. In order to improve the internal structure architecture of Evolutionary Algorithms as well as to learn which the adequate values of parameters and/or structure of operators are , a review sho...

In this work new safety systems multiobjective optimum design methodologies are introduced and compared. Various multicriteria evolutionary algorithms are analysed (SPEA2, NSGAII and controlled elitist-NSGAII) and applied to a Containment Spray Injection System of a nuclear power plant. Influence of various mutation rates is considered. A double mi...

In this paper we solve a state constrained optimal control problem using an intelligent system based on evolutionary self-learning computation. We try to find the optimal locations of liquid waste dumping sites in offshore waters, so that it is verified that the concentration of a considered pollutant does not exceed a pre-established limitation, e...

In this paper an alternative design for the internal structure of Evolutionary Algorithms is presented and a first implementation of such structure is tested. In order to improve the internal structure architecture of Evolutionary Algorithms as well as to learn which the adequate values of parameters and/or structure of operators are , a review sho...

Resumen—En este trabajo se presenta, en el campo de la Computación Evolutiva, una metodología que pretende ser un primer paso hacia un nuevo enfoque a la hora de afrontar la resolución de problemas de optimización, al que hemos denominado Evolución Flexible (EF). El procedimiento propuesto posee la característica de no tener que elegir a priori ent...

Two frame structure optimisation problems are handled. Firstly, the constrained minimum-mass problem, for which both continuous and discrete cases with ideal (without buckling effect and its own gravitational load) and real (with buckling effect and its own gravitational load) models are solved with several types of genetic algorithms. Results for...

A practical dynamical model of an efficient Simple Genetic Algorithm is presented, introducing in the matrix of the Nix and Vose Markov model a practical postulate related to the schema theorem, that induces deterministic correction factors in the matrix, through Heavisides unitary step function. This alteration permits SGA to evolve by efficient d...

Genetic algorithms have been used to solve a global sourcing problem, that is the allocation of production lots to different plants distributed all over the world in order to minimise production costs. Indeed some types of cars, like Fiat Palio and Siena, are called "world cars", as they are assembled in different sites in the world, often very far...

The unit commitment (UC) and Economic Dispatch (ED) are important part of the set of actions included in the concept of Power Systems Operation. In this paper we describe the application of Genetic Algoritms (GAs) to UC and ED problems using both binary and real coding, with increased efficiency because the use of Convergence Accelerators derived f...

In this paper we present a methodology of optimisation for the determination of the optimal locations of liquid waste dumping sites in the offshore waters. We try to minimise the waste disposal cost in marine waters for a finite number of sewage farms or accumulation sites from each ones starts off a pipeline, at the end of which there are a number...

Estabilidad de sistemas dinámicos. Asociados a modelos neuronales, diseñados para el cálculo de autovectores de operadores lineales y no linealesPedro José Zufiria Zatarain, Piedad Tolmos Rodríguez-Piñero, José Manuel Vegas Montaner

This paper deals with evolutionary processes, simulated on computers, i.e., Artificial Evolution or Evolutionary Computation (EC) [BFM97]. At least since 1994, when the first World Congress of Computational Intelligence (WCCI) [ZMR94] took place at Orlando, Florida, EC has become one out of three major domains of Computational Intelligence (CI), th...

This paper deals with evolutionary processes, simulated on computers, i.e., Artificial Evolution or Evolutionary Computation (EC) [BFM97]. At least since 1994, when the first World Congress of Computational Intelligence (WCCI) [ZMR94] took place at Orlando, Florida, EC has become one out of three major domains of Computational Intelligence (CI), th...

this paper is to provide a brief overview of some of our projects involving the application of evolutionary algorithms to industrial application problems. These projects are established at the Center for Applied Systems Analysis (Casa) within the Informatik Centrum Dortmund (ICD), a research institute providing technology transfer from university r...

this paper is to provide a brief overview of some of our projects involving the application of evolutionary algorithms to industrial application problems. These projects are established at the Center for Applied Systems Analysis (Casa) within the Informatik Centrum Dortmund (ICD), a research institute providing technology transfer from university r...

El objetivo del trabajo es incrementar la eficiencia computacional por reducción del tratamiento de la función objetivo introduciendo un patrón en el esquema que se acerque a la solución deseada. Con ello se reduce el cálculo de la función objetivo que en casi todos los casos representa aproximadamente el 80% de computación. El cromosoma patrón es...

Some time ago evolutionary algorithms were mainly a scientific topic related to computer science. Nowadays it is clear that real world applications exist and that an even larger impact can be foreseen in the near future in industrial applications. Sophisticated algorithms interfaced with Neural Networks. Fuzzy Logic, Gradient-based Algorithms, etc....

The preservation of the excellent image quality of the 'Roque de los Muchachos' Observatory (ORM) is one of the most important design criteria for the enclosure of the future large telescope. Additionally, the cost of a large telescope and its instrumentation is so high that it would be regrettable if its own enclosure deteriorates the telescope pe...

This chapter presents solution for a state constrained optimal control problem using an intelligent system based on evolutionary self-learning computation. The problem is solved under a parallel implementation linked to flexible evolution agent (FEA) using an Internet-based distributed computing environment. The aim of the FEA is to secure the high...

In order to find a map of wind velocities, this study tries to obtain an incompressible wind field that adjusts to an experimental one: also verifying the corresponding boundary conditions of physical interest. This problem has been solved by several authors using finite differences or standard finite element techniques. In this paper, this problem...

This is a study about one of the core questions in the GMRES(k) method regarding the obtaining of vector yk for the least-squares problem, argminy |Hky - β(n)e1|2 (see Saad and Schultz1). We propose a simple but efficient approach to the resolution of this problem and a low cost computation of the residual and the residual norm, including both in a...

This article investigates the thermal performance of the solidification process within a spherical enclosure including effects of natural convection. First, an experimental apparatus utilizing a copper ball filled with octadecane was designed and constructed. Experimental data of temperature profiles was obtained using different coolant temperature...

A new method for the analysis of parallel transmission lines in multilayered dielectric media is presented. The method is based on adaptive mixed finite element techniques with improved error estimators. The analysis can be used to extract accurately the interconnect capacitances for circuit and timing simulators in the design and verification phas...

En este trabajo se presentan formulaciones implícitas y explícitas para la resolución numérica del problema evolutivo de convección-difusión en 2-D, basadas en el método de las características. Se aborda un estudio comparativo sobre el comportamiento numérico de las distintas formulaciones propuestas. Se realizan diferentes aplicaciones numéricas u...

In this paper the use of a powerful single-objective optimization methodology in Multi-objective Optimization Algorithms (MOEAs) is introduced. The Flexible Evolution concepts (FE) have been recently developed and proved its efficiency gains compared with several Evolutionary Algorithms solving single-objective challenging problems. The main featur...

This paper deals with simulated annealing algorithms and their application to reduce simultaneously the band of a sparse matrix and their total number of null terms between the first non-null term in a row of the lower triangle and the diagonal term. The target of this application is to increase in practice, performance of ILU factorization as prec...

The purpose of this paper is to influence the researchers working in the field of algorithms for large scale systems about the efficiency of evolution algorithms as optimization techniques to explore robust large search spaces and find near-global optima. These evolutionary algorithms (EAs) can be an alternative to numerical methods in difficult op...

The generalized use of the conjugate gradient method for solving symmetric linear systems of equations has provided important results of convergence for this method. However, for nonsymmetric systems these studies are much more complicated. Along the last years many iterative methods for solving nonsymmetric linear systems have been published. This...