A Study of the Combination of Variation Operators in the NSGA-II Algorithm

Multi-objective evolutionary algorithms rely on the use of variation operators as their basic mechanism to carry out the evolutionary process. These operators are usually fixed and applied in the same way during algorithm execution, e.g., the mutation probability in genetic algorithms. This paper analyses whether a more dynamic approach combining different operators with variable application rate along the search process allows to improve the static classical behavior. This way, we explore the combined use of three different operators (simulated binary crossover, differential evolution’s operator, and polynomial mutation) in the NSGA-II algorithm. We have considered two strategies for selecting the operators: random and adaptive. The resulting variants have been tested on a set of 19 complex problems, and our results indicate that both schemes significantly improve the performance of the original NSGA-II algorithm, achieving the random and adaptive variants the best overall results in the bi- and three-objective considered problems, respectively.UNIVERSIDAD DE MÁLAGA. CAMPUS DE EXCELENCIA INTERNACIONAL ANDALUCÍA TEC

Computational prediction of remodeling of collagen fiber network in articular cartilage under dynamic unconfined compression

A poroelastic finite element model of a heterogeneous cartilage disk was created based on previous studies and experimental setups; this allows us to study cartilage behavior under dynamic unconfined compression. Previous studies have used a Post Hoc approach, which consist of searching for patterns or relationships between predicted mechanical parameters obtained through computational and experimental results. Our goal in this study is to take the same Post-Hoc approach and identify patterns between predicted mechanical parameters, such as fiber strain or stress, and experimentally-measured collagen fiber distribution (i.e. reorientation of fibers under dynamic unconfined compression). After computational predictions were obtained, it was observed that stress and pore pressure, in addition to fiber strain, are key to triggering the reorientation of collagen fibers in the cartilage tissue

Automatic Analysis of Facebook Posts and Comments Written in Brazilian Portuguese

Social networks and media are becoming increasingly important sources for knowing people\u27s opinions and sentiments on a wide variety of topics. The huge number of messages published daily in these media makes it impractical to analyze them without the help of natural language processing systems.This article presents an approach to cluster texts by similarity and identifying the sentiments expressed by comments on then (positive, negative and neutral, among others) in an integrated manner. Unlike most of the available studies that focus on the English language and use Twitter as a data source, we treat Brazilian Portuguese posts and comments published on Facebook. The proposed approach employs an unsupervised learning algorithm to group posts and a supervised algorithm to identify the sentiments expressed in comments to posts. In an experimental evaluation, a system that implements the proposed approach showed similar accuracy to that of human evaluators in the tasks of clustering and sentiment analysis, but performed the tasks in much less time

Biologically Plausible Connectionist Prediction of Natural Language Thematic Relations

In Natural Language Processing (NLP) symbolic systems, several linguistic phenomena, for instance, the thematic role relationships between sentence constituents, such as AGENT, PATIENT, and LOCATION, can be accounted for by the employment of a rule-based grammar. Another approach to NLP concerns the use of the connectionist model, which has the benefits of learning, generalization and fault tolerance, among others. A third option merges the two previous approaches into a hybrid one: a symbolic thematic theory is used to supply the connectionist network with initial knowledge. Inspired on neuroscience, it is proposed a symbolic-connectionist hybrid system called BIO theta PRED (BIOlogically plausible thematic (theta) symbolic-connectionist PREDictor), designed to reveal the thematic grid assigned to a sentence. Its connectionist architecture comprises, as input, a featural representation of the words (based on the verb/noun WordNet classification and on the classical semantic microfeature representation), and, as output, the thematic grid assigned to the sentence. BIO theta PRED is designed to ""predict"" thematic (semantic) roles assigned to words in a sentence context, employing biologically inspired training algorithm and architecture, and adopting a psycholinguistic view of thematic theory.Fapesp - Fundacao de Amparo a Pesquisa do Estado de Sao Paulo, Brazil[2008/08245-4

Solving a Real-World Structural Optimization Problem With a Distributed SMS-EMOA Algorithm

This paper addresses a real-world optimization problem in civil engineering. It lies in the dimensioning of a 162m long bridge composed of 1584 bars so that both its weight and its deformation are to be minimized. Evaluating each possible configuration of the bridge takes several seconds and, as a consequence, running a metaheuristic for several thousands of evaluations would require many days on one single processor. Our approach has been to develop a distributed master/worker version of SMS-EMOA, an indicator-based multiobjective algorithm. By combining the Java implementation of the algorithm in jMetal with the Condor distributed scheduler, we have been able to use more than 350 cores to obtain accurate results in a reasonable amount of time.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Improving the performance of web service recommenders using semantic similarity

This paper addresses issues related to recommending Semantic Web Services (SWS) using collaborative filtering (CF). The focus is on reducing the problems arising from data sparsity, one of the main difficulties for CF algorithms. Two CF algorithms are presented and discussed: a memory-based algorithm, using the k-NN method, and a model-based algorithm, using the k-means method. In both algorithms, similarity between users is computed using the Pearson Correlation Coefficient (PCC). One of the limitations of using the PCC in this context is that in those instances where users have not rated items in common it is not possible to compute their similarity. In addition, when the number of common items that were rated is low, the reliability of the computed similarity degree may also be low. To overcome these limitations, the presented algorithms compute the similarity between two users taking into account services that both users accessed and also semantically similar services. Likewise, to predict the rating for a not yet accessed target service, the algorithms consider the ratings that neighbor users assigned to the target service, as is normally the case, while also considering the ratings assigned to services that are semantically similar to the target service. The experiments described in the paper show that this approach has a significantly positive impact on prediction accuracy, particularly when the user-item matrix is sparse.Facultad de Informátic

A local anisotropic adaptive algorithm for the solution of low-Mach transient combustion problems

A novel numerical algorithm for the simulation of transient combustion problems at low Mach and moderately high Reynolds numbers is presented. These problems are often characterized by the existence of a large disparity of length and time scales, resulting in the development of directional flow features, such as slender jets, boundary layers, mixing layers, or flame fronts. This makes local anisotropic adaptive techniques quite advantageous computationally. In this work we propose a local anisotropic refinement algorithm using, for the spatial discretization, unstructured triangular elements in a finite element framework. For the time integration, the problem is formulated in the context of semi-Lagrangian schemes, introducing the semi-Lagrange-Galerkin (SLG) technique as a better alternative to the classical semi-Lagrangian (SL) interpolation. The good performance of the numerical algorithm is illustrated by solving a canonical laminar combustion problem: the flame/vortex interaction. First, a premixed methane-air flame/vortex interaction with simplified transport and chemistry description (Test I) is considered. Results are found to be in excellent agreement with those in the literature, proving the superior performance of the SLG scheme when compared with the classical SL technique, and the advantage of using anisotropic adaptation instead of uniform meshes or isotropic mesh refinement. As a more realistic example, we then conduct simulations of non-premixed hydrogenair flame/ vortex interactions (Test II) using a more complex combustion model which involves state-of-the-art transport and chemical kinetics. In addition to the analysis of the numerical features, this second example allows us to perform a satisfactory comparison with experimental visualizations taken from the literature.This research has been partially funded by projects MTM2010-18079 and CSD2010-00011 (CONSOLIDER-INGENIO) of the Spanish "Ministerio de Economía y Competitividad". The authors would like to thank Professors A. Liñán and R. Bermejo their priceless dedication and fruitful discussions, which have tremendously helped in our understanding of the physical phenomena involved in combustion problems, and in the development of the numerical methods suitable for integrating the equations of fluid mechanics

Improving the performance of web service recommenders using semantic similarity

This paper addresses issues related to recommending Semantic Web Services (SWS) using collaborative filtering (CF). The focus is on reducing the problems arising from data sparsity, one of the main difficulties for CF algorithms. Two CF algorithms are presented and discussed: a memory-based algorithm, using the k-NN method, and a model-based algorithm, using the k-means method. In both algorithms, similarity between users is computed using the Pearson Correlation Coefficient (PCC). One of the limitations of using the PCC in this context is that in those instances where users have not rated items in common it is not possible to compute their similarity. In addition, when the number of common items that were rated is low, the reliability of the computed similarity degree may also be low. To overcome these limitations, the presented algorithms compute the similarity between two users taking into account services that both users accessed and also semantically similar services. Likewise, to predict the rating for a not yet accessed target service, the algorithms consider the ratings that neighbor users assigned to the target service, as is normally the case, while also considering the ratings assigned to services that are semantically similar to the target service. The experiments described in the paper show that this approach has a significantly positive impact on prediction accuracy, particularly when the user-item matrix is sparse.Facultad de Informátic

Estudio sobre las sesiones de entrenamiento en los deportistas que se ejercitan en la vía “El Chaquiñán” de Cumbayá

Objetivos: Determinar la relación entre la valoración médica deportológica y los planes de entrenamiento, plan de nutrición e hidratación en los deportistas adultos jóvenes que usan la ruta “EL CHAQUIÑAN” de Cumbayá. Tipo de estudio: Se trata de un estudio trivariado ya que se miden las relaciones entre dos variables. Las correlaciones trivariadas serán utilizadas para estudiar como una variable influye en la otra. Es una investigación cuantitativa y cualitativa y de tipo observacional analítica porque se va a analizar la relación entre variables como Valoración Médica Deportológica, los planes de entrenamiento, planes de nutrición e hidratación con los valores sanguíneos de CPK y GLUCOSA y EMO en los deportistas adultos jóvenes que usan la ruta el Chaquiñán. Muestra: Para la toma de la muestra se empleó el método no probabilístico, mediante el uso del muestro aleatorio simple. Se tomarán 100 pacientes entre atletas y ciclistas que hacen uso de la vía “El Chaquiñán” en Cumbayá los días Domingos 2, 9, 16, 23 y 30 del mes de agosto del 2015. Material y Métodos: Hoja de encuesta a los pacientes luego de su actividad física en la vía “El Chaquiñán” los días domingos del mes de agosto del 2015, se tomaran las siguientes variables: Valoración Médica, Planificación de Ciclos de Entrenamiento, valor de CPK, glicemia postejercicio, densidad urinaria postentrenamiento. Plan de análisis: Se codificarán las variables para ser analizadas en el programa Statical Package for Social Sciences SPSS Versión 21 para elaboración de tablas y gráficos y el programa Microsoft Excel 2011 para Mac Versión 14.6.5 para almacenamiento de información

Actividad Física para pacientes con diagnóstico de cáncer. Guía de prescripción deportiva para Ecuador

This guide takes a tour of the various research studies on the benefits of professionally directed and monitored physical activity in patients diagnosed with cancer or who have survived chemotherapy or radiation treatments. It also discusses how to prescribe physical activity for diagnosed patients and when to start prescribing physical activity. It has been pointed out what kind of preventive measures should be promoted in physical activity together with nutrition to avoid the diagnosis of cancer. Finally, we have pointed out what type of nutrition a patient who carries out physical activity after the diagnosis of cancer should maintain, as well as the most appropriate exercises for the diagnosed patients. Concluding that the physical activity, controlled by a professional of the sport, is highly beneficial for the majority of the cases diagnosed with cancer and we propose its application to the Ecuadorian professionals.La presente guía hace un recorrido por las diferentes investigaciones en cuanto a los beneficios de la actividad física, dirigida y controlada por un profesional, en los pacientes diagnosticados con cáncer o que han sobrevivido a tratamientos de quimioterapia o radioterapia. También se ha analizado cómo debe realizarse la prescripción de actividad física para pacientes diagnosticados y en qué casos se debe iniciar la prescripción de actividad física. Se han señalado qué tipo de medidas preventivas se deben potenciar en la actividad física junto a la nutrición para evitar el diagnóstico de cáncer. Por último, hemos señalado qué tipo de nutrición debe mantener un paciente que realiza actividad física posterior al diagnóstico de cáncer, así como los ejercicios más adecuados a los pacientes diagnosticados. Concluyendo que la actividad física, controlada por un profesional del deporte, es altamente beneficiosa para la mayoría de los casos diagnosticados con cáncer y proponemos su aplicación a los profesionales ecuatorianos