On the use of preference-based evolutionary multi-objective optimization for solving a credibilistic portfolio selection model

The portfolio selection problem tries to identify the assets to allocate the capital, and the proportion to be devoted to each asset, for maximizing the returns at the minimum risk. By nature, this is a multi-objective optimization problem. In this work, we propose a three-objective model for portfolio selection, in which the uncertainty of the portfolio returns is modelled by means of LR-power fuzzy variables. We consider as criteria the credibilistic expected return (to be maxi- mized), the below-mean absolute semi-deviation as a risk measure (to be minimized), and a loss function which evaluates the credibility of achieving a non-positive return (to be minimized). The uncorrelation among the risk and loss measures concludes that they provide different information. Budget, cardinality, and diversification constraints are considered. To generate non-dominated portfolios fitting the investor' expectations, preference-based evolutionary algorithms are applied. The preferences are given by aspiration values to be attained by the objectives and profiles representing aggressive, cautious, and conservative investors are analysed. The results for data of the IBEX35 show that portfolios improving the preferences are found in the cautious and aggressive cases, while portfolios with objective values as close as possible to the expectations are obtained in the conservative case. In the generation process, the credibilistic loss has played an important role to and diversified portfolios.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

A-GWASF-GA: The New Version of GWASF-GA to Solve Many Objective Problems

A new version of the evolutionary algorithm based on GWASF-GA [1] is proposed in this work. GWASF-GA is an aggregation-based algorithm which uses the Tchebychev metric plus an augmentation term as fitness function and two reference points (the utopian and nadir points) to classify the individuals according to a set of widely-distributed weight vectors. Although this algorithm obtains a good approximation of the Pareto front (PF) for multi-objective optimization problems, this may be more difficult to obtain for many-objective optimization problems due to the fact that the weight vectors used are never updated along the search process. For this reason, we propose a new version of the algorithm, called A-GWASF-GA, in which a dynamic adjustment of the weight vectors is carried out. The main idea is to re-calculate some weight vectors in order to obtain solutions in parts of the PF with a lack of solutions. Firstly, a percentage (p) of the total number of evaluations is performed with the original GWASF-GA [1]. Secondly, during the rest of evaluations (1-p), we re-calculate na times the projection directions determined by a subset of Na weight vectors. The re-calculation process is based on a scattering level, a measure based on the distance of each solution and the solutions around it. According to the scattering level of the generated solutions, we detect the Na weight vectors projecting toward overcrowded areas of the PF and we re-calculate them so that their new projection directions point towards areas of the PF which are not so well approximated. In order to show the effectiveness of A-GWASF-GA, we compare it with NSGA-III [2, 3], MOEA/D [4], MOEA/D-AWA [5] and the original GWASF-GA.To evaluate their performance, we use the IGD metric [6]. The results of the computational experiment demonstrate the good performance of A-GWASF-GA in the novel many-objective optimization benchmark problems considered.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Las tics en la enseñanza universitaria : blogs digitales

This study is an innovative educational experience to analyse to what extent the use of blogs contributes to the acquisition of specific skills of a subject in Early Childhood Education Degree, and assess the level of learning that students considered achieved. A quantitative methodological approach based on the analysis of a closed questionnaire and on assessment rubric was used. The results allowed to verify that the use of blogs in the university is very useful to promote the active role of the student through a critical, reflective and collaborative learning, which allows you to get a high level of professional skills acquisition. Keywords: Blogs, collaborative learning, higher education, educational innovation, web technologies 2.0

The custom-made foot orthosis using the Central Stabilizer Element: nex concept of element

Foot orthoses have been applied for the management of lower limb disorders, mainly for those who develop foot pain. The Central Stabilizer Element (CSE) is a new element that contains the midfoot laterally when a plantar insole is manufactured. OBJECTIVES: - To determine the effect on foot pain of adding the Central Stabilizer Element during the manufacturing process of foot orthosis, -- - To describe the proportions of Central Stabilizer Element in terms of width and length of this element. METHODS: A sample comprising 130 patients (57 males and 73 females) with foot pain was recruited for this study, with the patients having supinated, neutral, pronated and overpronated feet. All the patients received a custom-made foot orthosis with the Central Stabilizer Element. The Central Stabilizer Element was made of resins of polyvinyl chloride, and is a device insert in foot orthosis that contains the midfoot laterally to control pronation and supination movements. Conclusion •The students know how to design the insole. •They know how to match different foot posture with the different types of insoles •We make our decisions based on the scientific evidence foundUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Un nuevo Algoritmo Evolutivo de Optimizacion Multiobjetivo basado en Preferencias: WASF-GA

IX Congreso Español de Metaheurísticas, Algoritmos Evolutivos y Bioinspirados - MAEB 2013.Para resolver problemas de optimizacion multiobjetivo, los algoritmos evolutivos basados en preferencias incorporan información preferencial en el proceso evolutivo, con el objetivo de encontrar un conjunto de soluciones Pareto optimas acordes a las preferencias del decisor (DM). En este trabajo, se propone un nuevo algoritmo evolutivo basado en preferencias que aproxima la region de la frontera Pareto optima que mejor se ajusta a los valores de aspiracion que el decisor desea alcanzar en cada objetivo. Estos valores constituyen las componentes de lo que se conoce como punto de referencia. El algoritmo hace uso de la conocida función escalarizada de logro de Wierzbicki para clasificar los individuos de cada generacion en diferentes fronteras. Dicha clasificacion se realiza en base a los valores que la función de logro alcanza para el punto de referencia proporcionado, considerando un conjunto de vectores de pesos. Los experimentos realizados sobre conocidos problemas test muestran unos resultados prometedores en cuanto a la calidad de las soluciones obtenidas, en comparacion a otros algoritmos existentes basados en puntos de referencia.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Exportación de palta Hass durante el periodo 2003-2013

En la actualidad La palta Hass se ha convertido en una gran alternativa dentro de los productos de exportación no tradicionales, aumentando el volumen y el valor exportado cada año. La palta, también conocida como aguacate, es una de las frutas que no solo tienen un sabor agradable sino también posee diferentes usos, principalmente se usa en la alimentación como complemento de todo tipo de comidas, de su rica materia grasa puede extraerse un aceite utilizado en la industria cosmética y farmacéutica. Es por ello que este producto se ha logrado posicionar en el mercado internacional. El objetivo de esta presente investigación es determinar la evolución de la exportación de palta Hass durante el periodo 2003-2013. Cabe destacar que, los conceptos de población, muestra y muestreo no son pertinentes en esta investigación, ya que, se utilizaran datos ex post facto, es decir datos que ya existen durante esos años como por ejemplo el valor de exportación, volumen de exportación y precio de exportación. Para analizar estos datos utilizaremos el método estadístico que consiste en la recopilación de datos, para luego organizarlo mediante tablas, luego presentarlo en grafico de líneas, y así de esta manera mostrar si hay una tendencia creciente, para luego describirlos. El resultado de la investigación reflejó que hay una tendencia creciente en la exportación de palta Hass durante el periodo 2003-2013, según muestran sus indicadores, lo cual es muy favorable para nuestro país ya que demuestra que el mercado internacional demanda cada vez más este producto

Hyperespectral images for the evaluation of the quality of minimally processed vegetables (spinach)

The production of minimally processed vegetables and fruits is an emergent sector, however these processes reduce the useful life of the products. Main preservation techniques such cold storage and modified atmosphere are limited. New treatments are being applied (O3 , UV‐C radiation, biodegradable films…etc.). The sector precise of cheap and fast techniques to evaluate the general quality and the security of the processed products, that constitute a tool of aid to the decision in the implementation of new procedures of packaging and/or treatments. Objectives: To explore hyperspectral imaging for monitoring the evolution of minimally processed leafy vegetables during shelf‐life . To identify and classify deterioration rates of the leaves through Multivariate analysis techniques (PLS‐DA

Movie Editing and Cognitive Event Segmentation in Virtual Reality Video

Traditional cinematography has relied for over a century on a well-established set of editing rules, called continuity editing, to create a sense of situational continuity. Despite massive changes in visual content across cuts, viewers in general experience no trouble perceiving the discontinuous flow of information as a coherent set of events. However, Virtual Reality (VR) movies are intrinsically different from traditional movies in that the viewer controls the camera orientation at all times. As a consequence, common editing techniques that rely on camera orientations, zooms, etc., cannot be used. In this paper we investigate key relevant questions to understand how well traditional movie editing carries over to VR. To do so, we rely on recent cognition studies and the event segmentation theory, which states that our brains segment continuous actions into a series of discrete, meaningful events. We first replicate one of these studies to assess whether the predictions of such theory can be applied to VR. We next gather gaze data from viewers watching VR videos containing different edits with varying parameters, and provide the first systematic analysis of viewers' behavior and the perception of continuity in VR. From this analysis we make a series of relevant findings; for instance, our data suggests that predictions from the cognitive event segmentation theory are useful guides for VR editing; that different types of edits are equally well understood in terms of continuity; and that spatial misalignments between regions of interest at the edit boundaries favor a more exploratory behavior even after viewers have fixated on a new region of interest. In addition, we propose a number of metrics to describe viewers' attentional behavior in VR. We believe the insights derived from our work can be useful as guidelines for VR content creation

Multispectral Vision for Monitoring Peach Ripeness

The main objective of this research was to develop an automatic procedure able to classify Rich Lady commercial peaches according to their ripeness stage through multispectral imaging techniques. A classification procedure was applied to the ratio images calculated as red (R, 680 nm) divided by infrared (IR, 800 nm), that is, R/IR images. Four image-based ripeness reference classes (A: unripe to D: overripe) were generated from 380 fruit images (season 1: 2006) by a nonsupervised classification method and evaluated according to reference measurements of the ripeness of the same samples: Magness-Taylor penetrometry firmness, low-mass impact firmness, reflectance at 680 nm (R680, and soluble solids content. The assignment of unknown sample images from those season 1 images (internal validation, n = 380) and of 240 images from the 2nd season (season 2: 2007) to the ripeness reference classes (external validation) was carried out by computing the minimum Euclidean distance (classification distance, Cd) between each unknown image histogram and the average histogram of each ripeness reference class. For both validation phases, firmness values decreased and R680 increased for increasing alphabetical order of image-based class letter, reflecting the ripening process. Moreover, 70% (season 1) and 80% (season 2) of the samples below bruise susceptibility firmness were classified into class D

Evaluación de técnicas acústicas para la determinación de firmeza en melocotón

Non destructive determination of stone fruit firmness is a critical factor for improving its quality and handling. This work applies available acoustic techniques to the determination peach firmness, considering and comparing different parameters obtained with 2 devices: AWETA-AFS (Acoustic Firmness Sensor), which integrates impact and acoustic response information; and a prototype device by LPF-TAG, which enables to analyze the whole acoustic spectra. Magness-Taylor, quasiestatic ball compression and non-destructive impact are used as firmness references, obtaining up to 86% R. La determinación no destructiva de la firmeza en melocotón es fundamental para mejorar la calidad y facilitar el manejo de esta fruta por la industria. El presente trabajo se plantea con el objetivo de estudiar la aplicación de técnicas acústicas en la caracterización de firmeza en melocotón. Para ello se evalúan y comparan distintos parámetros obtenidos mediante un sensor comercial, el dispositivo “Acoustic Firmness Sensor” (ASF de AWETA) que incorpora también un sensor de impacto; y un prototipo de equipo acústico desarrollado en el LPF-TAG, que permite analizar el espectro acústico completo. Como medidas de referencia se utilizaron: el ensayo Magness-Taylor (MT), la compresión quasiestática con contacto esférico (B) y la respuesta al impacto, ensayo no destructivo (IMP.) Como principales resultados destacan las correlaciones entre algunos de los parámetros acústicos con las variables de referencia (R de hasta 0,86