Solución en forma cerrada de sistemas acoplados de Riccati en teoría de juegos discretos

En este artículo se propone una solución no iterativa de sistemas acoplados matriciales de Riccati que aparecen en la resolución de teoría de juegos discretos cuando se aplica la estrategia de Nash en bucle abierto. Mediante el uso de transformaciones algebraicas apropiadas el problema. Se transforma en otro desacoplado para el que una solución en forma cerrada es viable.Peer Reviewe

A semi-automated method for daily age estimation in larval populations by discriminant function models

Discriminant analysis including the best age-correlated variables selected by SMLR’s to construct a predictive model based on somatic and otolith biometry was applied. Age of anchovy larvae ranging from 10 to 12 mm collected along Western Mediterranean coasts during MEDIAS209 survey were estimated by otolith microstructure analysis and compared with the number of daily increments estimated by the model. The model compound by Perimeter2 + Area2 was able to estimate correctly the age of the otoliths in 75% of the cases assuming ±1 day of error increasing to 90% assuming ±2 days of error with mean values of APE (3.33%) and CV (4.71%) systematically low. The results indicate the precision of the increment estimates. Moreover, no differences between the estimated ages from direct readings and those estimated by the model were observed. The proposed method implies a reduction in the subjectivity factor and the cost/benefit ratio for ageing studies in fish larvae.Postprint1,586

Huellas del joven Martínez Ruiz en el Azorín adulto: sobre el sistema ecléctico de la tetralogía crítica (1912-1915)

En este artículo se salvará la aparente distancia que separa al joven José Martínez Ruiz (1873-1967), simpatizante del anarquismo, del Azorín conservador en que se convirtió en su madurez. Para ello se presentará su tetralogía crítica, formada por Lecturas españolas (1912), Clásicos y modernos (1913), Los valores literarios (1914) y Al margen de los clásicos (1915), como el resultado de un anhelo juvenil por construir una historia de la literatura española. Se realizará un cotejo entre estas cuatro obras y el libro La evolución de la crítica, de 1899, con el objetivo de determinar qué influencia tuvieron las diversas escuelas teóricas examinadas en este opúsculo en su crítica literaria de madurez. De este análisis se concluirá que es posible apreciar una continuidad entre las metodologías críticas analizadas en La evolución de la crítica y las practicadas por el Azorín adulto. Asimismo, se propondrá que su labor crítica de madurez se sostiene sobre un sistema amplio y ecléctico heredado de estas teorías con las que se familiarizó en su juventud.This article expects to overcome the apparent distance noticed between the young José Martínez Ruiz (1873-1967), sympathizer of the anarchism, to the conservative author that later became known as Azorín. This way, his critical tetralogy (formed by Lecturas españolas, 1912, Clásicos y modernos, 1913, Los valores literarios, 1914, and Al margen de los clásicos, 1915) will be presented as a result of a young desire of writing a history of the Spanish literature. After this, the influence of his 1899 work La evolución de la crítica in the books mentioned above will be analyzed. In addition, it will be concluded that it is possible to appreciate continuity between the critical methodologies that Martínez Ruiz analyzed in La evolución de la crítica and those which he displayed to write his critical tetralogy. Finally, it will be proposed that his adult critical methodology is based on an eclectic system, which derives from the different theories of literary criticism that he learnt as a young writer

An exogenous protease increases enzymic activities, microbial numbers and fiber degraation by mixed ruminal microorganisms in continuous culture

Contributed to: Conference on Gastrointestinal Function (Chicago, Illinois, Mar 10-12, 2003).The effects of pH and addition of a protease mixture on the fermentation characteristics of a total mixed ration (TMR) were investigated in a dual-flow continuous culture apparatus, using a 4 x 4 Latin Square design with a 2 x 2 factorial arrangement of treatments. The diet (DM basis) consisted of 30% alfalfa hay, 30% corn silage and 40% rolled corn. The silage and the grain were milled fresh, mixed with the alfalfa and treated with the enzyme (1.5 μL/g feed) daily. Ruminal fluid was collected 2 h post-feeding from 3 lactating dairy cows fed a TMR. Fermenters were fed 80 g DM/d in equal portions every 12 h. Treatments were control (C) and enzymetreated (T) TMR at either high pH (HC and HT) or low pH (LC and LT). The pH was altered by diluting the artificial saliva to 60% of its original composition. Enzymic activities and total and cellulolytic bacterial numbers were determined on the liquid phase of the fermenter contents, 6 h post-feeding. Fiber degradation was determined from the outflow residues. Enzyme addition increased (P < 0.05) xylanase, xylosidase, endoglucanase, and protease activities (608 vs. 750; 0.48 vs. 0.80; 82 vs. 112; and 1.2 vs. 7.5 units for C and T, respectively), whereas it tended (P < 0.12) to increase exoglucanase and glucosidase activities (0.8 vs. 1.4; and 4.7 vs. 5.9 units). However, enzyme did not affect (P = 0.18) arabinofuranosidase activity (5.2 vs. 6.8). Total microbial numbers (expressed as Log10) were increased (P < 0.05) at low pH (9.13 vs. 9.36) but enzyme had no effect (P = 0.13). Cellulolytic bacteria were reduced (P < 0.02) at low pH (3.91 vs. 2.79), with no effect (P = 0.88) of enzyme. Low pH reduced (P < 0.001) NDF, ADF, and cellulose degradation. NDF degradation was increased (P < 0.01) by enzyme addition (20% vs. 27%) but ADF was unaffected (P < 0.20), resulting in an increase (P < 0.001) in hemicellulose degradation. It is speculated that the enzyme removed structural barriers present in the feed, allowing a more rapid colonization of the fiber by ruminal microorganisms.Peer reviewe

Algoritmos de aprendizaje evolutivo y estadístico para la determinación de mapas de malas hierbas utilizando técnicas de teledetección

Este trabajo aborda la resolución de problemas de clasificación binaria utilizando una metodología híbrida que combina la regresión logística y modelos evolutivos de redes neuronales de unidades producto. Para estimar los coeficientes del modelo lo haremos en dos etapas, en la primera aprendemos los exponentes de las funciones unidades producto, entrenando los modelos de redes neuronales mediante computación evolutiva y una vez estimados el número de funciones potenciales y los exponentes de estas funciones, se aplica el método de máxima verosimilitud al espacio de características formado por las covariables iniciales junto con las nuevas funciones de base obtenidas al entrenar los modelos de unidades producto. Esta metodología híbrida en el diseño del modelo y en la estimación de los coeficientes se aplica a un problema real agronómico de predicción de presencia de la mala hierba Ridolfia segetum Moris en campos de cosecha de girasol. Los resultados obtenidos con este modelo mejoran los conseguidos con una regresión logística estándar en cuanto a porcentaje de patrones bien clasificados sobre el conjunto de generalización

Projection based ensemble learning for ordinal regression

The classification of patterns into naturally ordered labels is referred to as ordinal regression. This paper proposes an ensemble methodology specifically adapted to this type of problems, which is based on computing different classification tasks through the formulation of different order hypotheses. Every single model is trained in order to distinguish between one given class (k) and all the remaining ones, but grouping them in those classes with a rank lower than k, and those with a rank higher than k. Therefore, it can be considered as a reformulation of the well-known one-versus-all scheme. The base algorithm for the ensemble could be any threshold (or even probabilistic) method, such as the ones selected in this paper: kernel discriminant analysis, support vector machines and logistic regression (all reformulated to deal with ordinal regression problems). The method is seen to be competitive when compared with other state-of-the-art methodologies (both ordinal and nominal), by using six measures and a total of fifteen ordinal datasets. Furthermore, an additional set of experiments is used to study the potential scalability and interpretability of the proposed method when using logistic regression as base methodology for the ensemble

Borderline kernel based over-sampling

Nowadays, the imbalanced nature of some real-world data is receiving a lot of attention from the pattern recognition and machine learning communities in both theoretical and practical aspects, giving rise to di erent promising approaches to handling it. However, preprocessing methods operate in the original input space, presenting distortions when combined with kernel classi ers, that operate in the feature space induced by a kernel function. This paper explores the notion of empirical feature space (a Euclidean space which is isomorphic to the feature space and therefore preserves its structure) to derive a kernel-based synthetic over-sampling technique based on borderline instances which are considered as crucial for establishing the decision boundary. Therefore, the proposed methodology would maintain the main properties of the kernel mapping while reinforcing the decision boundaries induced by a kernel machine. The results show that the proposed method achieves better results than the same borderline over- sampling method applied in the original input spac