Induction of Subgoal Automata for Reinforcement Learning

In this work we present ISA, a novel approach for learning and exploiting subgoals in reinforcement learning (RL). Our method relies on inducing an automaton whose transitions are subgoals expressed as propositional formulas over a set of observable events. A state-of-the-art inductive logic programming system is used to learn the automaton from observation traces perceived by the RL agent. The reinforcement learning and automaton learning processes are interleaved: a new refined automaton is learned whenever the RL agent generates a trace not recognized by the current automaton. We evaluate ISA in several gridworld problems and show that it performs similarly to a method for which automata are given in advance. We also show that the learned automata can be exploited to speed up convergence through reward shaping and transfer learning across multiple tasks. Finally, we analyze the running time and the number of traces that ISA needs to learn an automata, and the impact that the number of observable events has on the learner's performance.Comment: Preprint accepted for publication to the 34th AAAI Conference on Artificial Intelligence (AAAI-20

Modelling expected shortfall using tail entropy

Given the recent replacement of value-at-risk as the regulatory standard measure of risk with expected shortfall (ES) undertaken by the Basel Committee on Banking Supervision, it is imperative that ES gives correct estimates for the value of expected levels of losses in crisis situations. However, the measurement of ES is affected by a lack of observations in the tail of the distribution. While kernel-based smoothing techniques can be used to partially circumvent this problem, in this paper we propose a simple nonparametric tail measure of risk based on information entropy and compare its backtesting performance with that of other standard ES models

Concept of Inverted Refractive-Index-Contrast Grating Mirror and Exemplary Fabrication by 3D Microprinting

Highly reflective mirrors are indispensable components in a variety of state-of-the-art photonic devices. Typically used, bulky, multi-layered distributed Bragg (DBR) reflectors are limited to lattice-matched semiconductors or nonconductive dielectrics. Here, we introduce an inverted refractive-index-contrast grating (ICG), as compact, single layer alternative to DBR. In the ICG, a subwavelength one-dimensional grating made of a low refractive index material is implemented on a high refractive index cladding. Our numerical simulations show that the ICG provides nearly total optical power reflectance for the light incident from the side of the cladding whenever the refractive index of the grating exceeds 1.75, irrespective of the refractive index of the cladding. Additionally, the ICG enables polarization discrimination and phase tuning of the reflected and transmitted light, the property not achievable with the DBR. We experimentally demonstrate a proof-of-concept ICG fabricated according to the proposed design, using the technique of 3D microprinting in which thin stripes of IP-Dip photoresist are deposited on a Si cladding. This one-step method avoids laborious and often destructive etching-based procedures for grating structuration, making it possible to implement the grating on any arbitrary cladding material

Tecnologías aplicadas para el aprendizaje escolar en niños con inteligencias múltiples

El enfoque actual sobre Educación Inclusiva, que plantea contemplar la diversidad de todos los estudiantes del sistema para poder dar respuestas adecuadas a cada uno desde las propuestas áulicas e institucionales. El proyecto propone contribuir en el fortalecimiento de las actividades de investigación aplicada a partir de la utilización y análisis de herramientas de software que utilicen interfaces gestuales para ser utilizados en la construcción de contextos pedagógicos heterogéneos concebidos para una educación diversa. En una primera etapa, la investigación se focalizará en el trastorno de espectro autista de alto funcionamiento, analizando las posibilidades de transferencia tecnológica a escuelas especiales que trabajen con niños con esta u otras dificultades de aprendizaje. Los niños con TEA, como también otros niños que no padecen este trastorno, presentan una afinidad por las Tecnologías de la Información y la Comunicación (TIC) y su aplicación es de gran ayuda para fomentar, mediante juegos, la inclusión del niño en el universo simbólico teniendo como punto principal el valor del juego enunciado por Jean Piaget en su Teoría Estructuralista. Se plantea la implementación de Kinems ya que ofrece modalidades naturales de interacción del usuario y parece ser muy beneficioso para la población con el trastorno mencionado en edades tempranas debido a la combinación de actividades físicas con tareas de entrenamiento cognitivo.Sociedad Argentina de Informática e Investigación Operativ

Tecnologías aplicadas para el aprendizaje escolar en niños con inteligencias múltiples

El enfoque actual sobre Educación Inclusiva, que plantea contemplar la diversidad de todos los estudiantes del sistema para poder dar respuestas adecuadas a cada uno desde las propuestas áulicas e institucionales. El proyecto propone contribuir en el fortalecimiento de las actividades de investigación aplicada a partir de la utilización y análisis de herramientas de software que utilicen interfaces gestuales para ser utilizados en la construcción de contextos pedagógicos heterogéneos concebidos para una educación diversa. En una primera etapa, la investigación se focalizará en el trastorno de espectro autista de alto funcionamiento, analizando las posibilidades de transferencia tecnológica a escuelas especiales que trabajen con niños con esta u otras dificultades de aprendizaje. Los niños con TEA, como también otros niños que no padecen este trastorno, presentan una afinidad por las Tecnologías de la Información y la Comunicación (TIC) y su aplicación es de gran ayuda para fomentar, mediante juegos, la inclusión del niño en el universo simbólico teniendo como punto principal el valor del juego enunciado por Jean Piaget en su Teoría Estructuralista. Se plantea la implementación de Kinems ya que ofrece modalidades naturales de interacción del usuario y parece ser muy beneficioso para la población con el trastorno mencionado en edades tempranas debido a la combinación de actividades físicas con tareas de entrenamiento cognitivo.Sociedad Argentina de Informática e Investigación Operativ

Effects of Biological and Chemical Degradation on the Properties of Scots Pine Wood—Part I: Chemical Composition and Microstructure of the Cell Wall

Research on new conservation treatment for archaeological wood requires large amounts of wooden material. For this purpose, artificial wood degradation (biological—using brown-rot fungus Coniophora puteana, and chemical—using NaOH solution) under laboratory conditions was conducted to obtain an abundance of similar samples that mimic naturally degraded wood and can serve for comparative studies. However, knowledge about its properties is necessary to use this material for further study. In this study, the chemical composition and microstructure of degraded cell walls were investigated using FT-IR, XRD, helium pycnometry and nitrogen absorption methods. The results show that biological degradation caused the loss of hemicelluloses and celluloses, including the reduction in cellulose crystallinity, and led to lignin modification, while chemical degradation mainly depleted the amount of hemicelluloses and lignin, but also affected crystalline cellulose. These changes affected the cell wall microstructure, increasing both surface area and total pore volume. However, the chemical degradation produced a greater number of mesopores of smaller size compared to fungal decomposition. Both degradation processes weakened the cell wall’s mechanical strength, resulting in high shrinkage of degraded wood during air-drying. The results of the study suggest that degraded wood obtained under laboratory conditions can be a useful material for studies on new consolidants for archaeological wood

Effects of Biological and Chemical Degradation on the Properties of Scots Pine Wood—Part I: Chemical Composition and Microstructure of the Cell Wall

Research on new conservation treatment for archaeological wood requires large amounts of wooden material. For this purpose, artificial wood degradation (biological—using brown-rot fungus Coniophora puteana, and chemical—using NaOH solution) under laboratory conditions was conducted to obtain an abundance of similar samples that mimic naturally degraded wood and can serve for comparative studies. However, knowledge about its properties is necessary to use this material for further study. In this study, the chemical composition and microstructure of degraded cell walls were investigated using FT-IR, XRD, helium pycnometry and nitrogen absorption methods. The results show that biological degradation caused the loss of hemicelluloses and celluloses, including the reduction in cellulose crystallinity, and led to lignin modification, while chemical degradation mainly depleted the amount of hemicelluloses and lignin, but also affected crystalline cellulose. These changes affected the cell wall microstructure, increasing both surface area and total pore volume. However, the chemical degradation produced a greater number of mesopores of smaller size compared to fungal decomposition. Both degradation processes weakened the cell wall’s mechanical strength, resulting in high shrinkage of degraded wood during air-drying. The results of the study suggest that degraded wood obtained under laboratory conditions can be a useful material for studies on new consolidants for archaeological wood

Mental health in Germany in the first weeks of the Russo-Ukrainian war

Background In the connected world, although societies are not directly involved in a military conflict, they are exposed to media reports of violence. Aims We assessed the effects of such exposures on mental health in Germany during the military conflict in Ukraine. Method We used the German population-based cohort for digital health research, DigiHero, launching a survey on the eighth day of the Russo-Ukrainian war. Of the 27 509 cohort participants from the general population, 19 444 (70.7%) responded within 17 days. We measured mental health and fear of the impact of war compared with other fears (natural disasters or health-related). Results In a subsample of 4441 participants assessed twice, anxiety in the population (measured by the Generalised Anxiety Disorder-7 screener) was higher in the first weeks of war than during the strongest COVID-19 restrictions. Anxiety was elevated across the whole age spectrum, and the mean was above the cut-off for mild anxiety. Over 95% of participants expressed various degrees of fear of the impact of war, whereas the percentage for other investigated fears was 0.47–0.82. A one-point difference in the fear of the impact of war was associated with a 2.5 point (95% CI 2.42–2.58) increase in anxiety (11.9% of the maximum anxiety score). For emotional distress, the increase was 0.67 points (0.66–0.68) (16.75% of the maximum score). Conclusions The population in Germany reacted to the Russo-Ukrainian war with substantial distress, exceeding reactions during the strongest restrictions in the COVID-19 pandemic. Fear of the impact of war was associated with worse mental health

Anxiety, depressive symptoms, and distress over the course of the war in Ukraine in three federal states in Germany

IntroductionThe Russian invasion of Ukraine and the resulting consequences are in the center of political discussions, media, and likely individual thinking of the population in Germany. Yet, the impact of this prolonged exposure on mental health is not known hitherto.MethodsUsing the population based cohort study DigiHero from three federal states (Saxony-Anhalt, Saxony, and Bavaria), we assessed anxiety levels (GAD-7), depressive symptoms (PHQ-9), and distress (modified PDI) in the first weeks of war and 6 months later.ResultsOf those 19,432, who responded in the first weeks of war, 13,934 (71.1%) responded also 6 months later. While anxiety and emotional distress decreased during the 6 months, their average scores were still elevated, and a substantial fraction of respondents displayed clinically relevant sequelae. Persons from low-income households were especially affected, specifically by fears related to the personal financial situation. Those who reacted with a particularly strong fear in the beginning of war were more likely to have persistent clinically relevant symptoms of depression and anxiety also 6 months later.DiscussionThe Russian invasion of Ukraine is accompanied by continuing impairment of mental health in the German population. Fears surrounding the personal financial situation are a strong determinant