Studying Generalization on Memory-Based Methods in Continual Learning

One of the objectives of Continual Learning is to learn new concepts continually over a stream of experiences and at the same time avoid catastrophic forgetting. To mitigate complete knowledge overwriting, memory-based methods store a percentage of previous data distributions to be used during training. Although these methods produce good results, few studies have tested their out-of-distribution generalization properties, as well as whether these methods overfit the replay memory. In this work, we show that although these methods can help in traditional in-distribution generalization, they can strongly impair out-of-distribution generalization by learning spurious features and correlations. Using a controlled environment, the Synbol benchmark generator (Lacoste et al., 2020), we demonstrate that this lack of out-of-distribution generalization mainly occurs in the linear classifier

Some characteristics of the M function methodology to describe the reinjection process in chaotic intermittency

The M function methodology allows calculating the statistical properties of intermittency in a broad class of one-dimensional maps. It has shown to be very accurate in type I, II, III and V intermittencies; and it also includes the uniform reinjection as a particular case. This paper studies some properties of the M function methodology. We establish the conditions that a reinjection probability density function must verify to obtain and we describe new pathological cases where the reinjection is not uniform, but the characteristic relation is the same that for uniform reinjection.Fil: Elaskar, Sergio Amado. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Estudios Avanzados en Ingeniería y Tecnología. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Estudios Avanzados en Ingeniería y Tecnología; ArgentinaFil: del Rio, Ezequiel(EXT). Universidad Politécnica de Madrid; EspañaFil: Gutierrez Marcantoni, Luis Felipe. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Aeronáutica; Argentin

Dominant height growth equations including site attributes in the generalized algebraic difference approach

We present a new dynamic dominant height growth model based on Cieszewski’s generalized algebraic difference approach (GADA) advanced dynamic site equation strengthened by the use of explicit climate and soil variables (i.e., H = f(H0,T0, T, site conditions)). The results suggest that the inclusion of climatic variables would improve the applicability of the inter-regional model in regions in which climate and soil type lead to intra-regional variability. The new model reduces the bias present in a previous dynamic model that did not include climatic attributes and improves the model efficiency across the different age classes. Climate has a multiplicative effect on dominant tree growth in the early development stages (<20 years) and an additive effect in older stands

Stability of smectic phases in the Gay–Berne model

We present a detailed computer simulation study of the phase behavior of the Gay–Berne liquid crystal model with molecular anisotropy parameter k=4.4. According to previous investigations: (i) this model exhibits isotropic (I), smectic-A (Sm-A), and smectic-B (Sm-B) phases at low pressures, with an additional nematic (N) phase between the I and Sm-A phases at sufficiently high pressures; (ii) the range of stability of the Sm-A phase turns out to be essentially constant when varying the pressure, whereas other investigations seem to suggest a pressure-dependent Sm-A range; and (iii) the range of stability of the Sm-B phase remains unknown, as its stability with respect to the crystal phase has not been previously considered. The results reported here do show that the Sm-A phase is stable over a limited pressure range, and so it does not extend to arbitrarily low or high pressures. This is in keeping with previous investigations of the effect of molecular elongation on the phase behavior of Gay–Berne models. A detailed study of the melting transition at various pressures shows that the low-temperature crystalline phase melts into an isotropic liquid at very low pressures, and into a nematic liquid at very high pressures. At intermediate pressures, the crystal melts into a Sm-A liquid and no intermediate Sm-B phase is observed. On the basis of this and previous investigations, the reported Sm-B phase for Gay–Berne models appears to be a molecular solid rather than a smectic liquid phase.Financial support of the Spanish DGICYT (Dirección General de Investigación Científica y Técnica) under Project No. BFM-2001-1420-C02-02 is acknowledged. Additional support from Universidad de Huelva and Junta de Andalucía is also acknowledged

Molecular simulation of model liquid crystals in a strong aligning field

We report a computer simulation study of systems of perfectly aligned molecules interacting through the Gay–Berne (GB) potential model for two different values of the molecular anisotropy parameter k, namely 3 and 4.4. The models are appropriate to gauge the effects of strong aligning fields on the thermodynamics and structural properties of thermotropic liquid crystals. According to our results, one of the main effects of the external field is to increase the range of stability of the smectic A phase, which indicates the existence of a strong coupling between orientational and translational order. For the k=3 GB model the smectic phase, which is not stable in the absence of the field, is promoted when the molecules are constrained to be parallel. According to the simulation results, the smectic A-nematic transition is, in general, continuous; however, this transition appears to be first order at low pressure for the k=4.4 GB fluid model.Financial support is due to project number FIS2004- 06627-C02-01 of the Spanish Dirección General de Investigación. Additional support from Universidad de Huelva and Junta de Andalucía is also acknowledged

Differences in stem radial variation between Pinus pinaster Ait. and Quercus pyrenaica Willd. may release inter-specific competition

Species complementarity by morphological and physiological trait differences could cause distinct temporal and spatial use of resources. Accordingly, mixed stands may enhance production, biodiversity and/or provide a better adaptation to future climate conditions. We aim to identify species differences in intra-annual stem radial variation patterns, and to recognize species-specific responses to contrasting weather conditions at key intraannual growth phases. Stem radial variation was recorded from high temporal resolution point dendrometers (2012-2014) installed on twelve dominant maritime pine and Pyrenean oak trees in two mixed stands in central Spain. Species differences in stem radial variation were analyzed by synchrony statistics, intra-annual pattern modelling, and evaluating the dependence of main intra-annual growth phases on climate conditions. Both species showed important differences on intra-annual radial increment pattern despite general stem radial variation synchrony. Radial increment onset was earlier for maritime pine during the spring and rainy autumns. Species-specific responses to weather indicate that stem radial variation increased with autumn temperature in maritime pine, but decreased in Pyrenean oak trees. However, summer vapor pressure deficit may reduce stem radial variation for maritime pine. Therefore, maritime pine would adapt more efficiently to warmer temperatures associated with climate change, although summer water stress may reduce this competitive bonus

Religión como modeladora de idearios y comportamientos relacionados con la fecundidad

It is considered that religious beliefs, moral values and the way in which people conceive reality influence human rationality, and, therefore, people’s decisions. Although these aspects are outside the market, they do still influence the functioning of the economy. This document addresses an analysis, from a perspective based on the economics of culture and religion, abouthow religion and the socioeconomic context shape people’s ideas and behaviors related to the decisions about having children in families living in Cartagena de Indias - Colombia. Throughout this research we developed a theoretical-explanatory study and provided empirical evidence about the situation of the city associating the variables of interest.Se considera que las creencias religiosas, los valores y los modos de concebir la realidad inciden en todo racionamiento del ser humano y, por tanto, en sus decisiones. Así, desde el punto de vista económico, a pesar de que estos aspectos se encuentran por fuera de los mercados, influyen sobre el funcionamiento de la economía. En este documento se propone –bajo la perspectiva de la economía de la cultura y de la economía de la religión– analizar la forma en que la religión y el contexto socioeconómico modelan los idearios y los comportamientos relacionados con las decisiones de tener hijos en las familias de la ciudad de Cartagena (Colombia). Se desarrolló un estudio teórico-explicativo, y se aportó evidencia empírica de la situación en la ciudad en la que se vincularon las variables de interés

Volubilidade narrativa e moralismo pendular em Lavoura Arcaica: enfrentamento e conformação dos costumes no contexto ditatorial

Esse trabalho investiga o desempenho narrativo da obra Lavoura Arcaica (1975), de Raduan Nassar, a fim de mostrar que a perspectiva do protagonista sobre os eventos revela um moralismo pendular que ora se expande na libertação da subjetividade ora se consterna a reproduzir aspectos conservadores. Desse modo, através da forma estética, é possível compreender contradições sociais a expor o contexto histórico da produção do romance que caminha tanto para o questionamento do regime ditatorial brasileiro quanto silencia a repressão. A contradição social é representada com recursos estéticos também contraditórios, tais como a postura narrativa oscilante e o conteúdo moralista pendente. Assim, obra consegue demonstrar o início do processo de abertura política, perpetuado no governo de Ernesto Geisel, direcionando o processo de redemocratização do país, sendo marcado por questionamentos de valores morais, ao mesmo tempo em que ainda convive com a sentença da morte de Vladimir Herzog. Através do engenho narrativo, a moralidade e as relações histórico-sociais são deflagradas na análise do texto. Para essa execução, referências como Sussekind, Schwarz, Vázquez são indispensáveis, já que ajudam a entender o contexto e o engendramento textual, além da discussão sobre a moralidade, expondo seus aspectos potenciais e retrógrados