A computational model for generating visually pleasing video game maps

In this work we introduce a computational model based on theories of graphical design to generate visually pleasing video game maps. We cast the problem of map generation as an optimization problem and prove it to be computationally hard. Then, we propose a heuristic search approach to solve the map generation problem and use it to generate levels of a clone of Super Mario Bros (SMB) called Infinite Mario Bros (IMB). Before evaluating the levels of IMB generated by our system, we perform a detailed study of the approaches commonly used to evaluate the content generated by computer programs. The evaluation used in previous works often relies on computational metrics. While these metrics are important for an initial exploratory evaluation of the content generated, it is not clear whether they are able to capture the player’s perception of the content generated. In this work we compare the insights gained from a user study with IMB levels generated by different systems with the insights gained from analyzing computational metric values. Our results suggest that current computational metrics should not be used in lieu of user studies for evaluating content generated by computer programs. Using the insights gained in our previous experiment, we performed another user study to evaluate the IMB levels generated by our method. The results show the advantage of our method over other approaches in terms of visual aesthetics and enjoyment. Finally, we performed one last user study that showed that our method is able to generate IMB levels with striking similarity to SMB levels created by professional designers.Neste trabalho apresentamos um modelo computacional baseado em teorias de design para gerar mapas de jogos de plataforma visualmente agradáveis. Nós estudamos o problema de geração de mapas como um problema de otimização e provamos que uma versão simplificada do problema é computacionalmente difícil. Em seguida, propomos uma abordagem de busca heurística para resolver o problema de geração de mapas e utilizamos ela para gerar níveis de um clone do Super Mario Bros (SMB), chamado Infinite Mario Bros (IMB). Antes de avaliar os níveis de IMB gerados pelo nosso sistema, realizamos um estudo detalhado das abordagens comumente utilizadas para avaliar o conteúdo gerado por programas de computador. A avaliação utilizada em trabalhos anteriores utiliza apenas métricas computacionais. Embora esses indicadores são importantes para uma avaliação inicial e exploratória do conteúdo gerado, não é claro se são capazes de capturar a percepção do jogador sobre o conteúdo gerado. Neste trabalho, comparamos os conhecimentos adquiridos a partir de um estudo com seres humanos usando níveis de IMB gerados por diferentes sistemas, com os conhecimentos adquiridos a partir de análise dos valores de métricas computacionais. Os nossos resultados sugerem que as m ́etricas computacionais atuais não devem substituir estudos com seres humanos para avaliar o conteúdo gerado por programas de computador. Usando os conhecimentos adquiridos em nosso experimento anterior, foi realizado outro estudo com seres humanos para avaliar os níveis de IMB gerados pelo nosso método. Os resultados mostram a vantagem do nosso método em relação a outras abordagens em termos de estética visual e diversão. Finalmente, foi realizado outro estudo com seres humanos, mostrando que o nosso método é capaz de gerar níveis de IMB semelhantes aos níveis de SMB criados por designers profissionais.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Bootstrap testing for cross-correlation under low firing activity

A new cross-correlation synchrony index for neural activity is proposed. The index is based on the integration of the kernel estimation of the cross-correlation function. It is used to test for the dynamic synchronization levels of spontaneous neural activity under two induced brain states: sleep-like and awake-like. Two bootstrap resampling plans are proposed to approximate the distribution of the test statistics. The results of the first bootstrap method indicate that it is useful to discern significant differences in the synchronization dynamics of brain states characterized by a neural activity with low firing rate. The second bootstrap method is useful to unveil subtle differences in the synchronization levels of the awake-like state, depending on the activation pathway.Comment: 22 pages, 7 figure

Multi-Instantons and Multi-Cuts

We discuss various aspects of multi-instanton configurations in generic multi-cut matrix models. Explicit formulae are presented in the two-cut case and, in particular, we obtain general formulae for multi-instanton amplitudes in the one-cut matrix model case as a degeneration of the two-cut case. These formulae show that the instanton gas is ultra-dilute, due to the repulsion among the matrix model eigenvalues. We exemplify and test our general results in the cubic matrix model, where multi-instanton amplitudes can be also computed with orthogonal polynomials. As an application, we derive general expressions for multi-instanton contributions in two-dimensional quantum gravity, verifying them by computing the instanton corrections to the string equation. The resulting amplitudes can be interpreted as regularized partition functions for multiple ZZ-branes, which take into full account their back-reaction on the target geometry. Finally, we also derive structural properties of the trans-series solution to the Painleve I equation.Comment: 34 pages, 3 figures, JHEP3.cls; v2: added references, minor changes; v3: added 1 reference, more minor changes, final version for JMP; v4: more typos correcte

Redundancia de las medidas de centralidad en Infraestructuras del Mercado Financiero

El concepto de centralidad ha sido ampliamente utilizado para monitorear sistemas con estructura de red ya que permite identificar a los participantes más influyentes. Las labores de monitoreo pueden ser difíciles de realizar si el número de participantes en esos sistemas es considerablemente amplio o si las medidas de centralidad producen resultados no coincidentes o generan señales mixtas. Este documento usa el análisis de componentes principales para evaluar un conjunto de medidas de centralidad calculadas para las instituciones financieras que participan en cuatro infraestructuras de los mercados financieros en Colombia. Los resultados obtenidos son utilizados para construir índices generales de centralidad, utilizando como insumos las medidas de centralidad más fuertes y dejando de lado aquellas consideradas redundantes.The concept of centrality has been widely used to monitor systems with a network structure because it allows identifying their most influential participants. But this monitoring task can be difficult if the number of system participants is considerably large or if the wide variety of centrality measures currently available produce non-coincident (or mixed) signals. This document uses principal component analysis to evaluate a set of centrality measures calculated for the financial institutions that participate in four financial market infrastructures of Colombia. The results obtained are used to construct general indices of centrality, using the strongest measures of centrality as inputs, and leaving aside those considered redundant.Enfoque Este documento estudia medidas de centralidad calculadas para el Sistema de Pagos de Alto Valor (CUD), la Cámara de Compensación de Divisas (CCDC), y los depósitos centrales de valores (DCV y Deceval). Estas cuatro infraestructuras del mercado financiero colombiano son sistemas con estructura de red, conformados por un gran número de participantes (instituciones financieras) que se encuentran conectados mediante relaciones de pagos, intercambios o transacciones similares. Su buen funcionamiento es fundamental para el buen desempeño del sistema financiero, y, por consiguiente, de la economía en general. Esto implica que cambios en la actividad de sus participantes o choques exógenos pueden generar efectos no deseados en esos sistemas. Es por esa razón que tanto bancos centrales como agencias de supervisión realizan un continuo seguimiento a la actividad de las instituciones que participan en esas infraestructuras. Este documento hace uso del criterio de centralidad para determinar qué tan importante es cada uno de los participantes en esas infraestructuras del mercado financiero. Contribución Las medidas de centralidad permiten monitorear a los participantes de sistemas con estructura de red e identificar a los más centrales; es decir, a aquellos que pueden generar mayores impactos en caso de incumplimiento. Sin embargo, esas labores de monitoreo pueden ser difíciles de realizar si el número de participantes en esos sistemas es considerablemente alto, o si las medidas de centralidad producen resultados no coincidentes o generan señales mixtas. En este documento se evalúan veintiséis medidas de centralidad para cada participante de cada infraestructura del mercado financiero. Se incluyen medidas de centralidad para redes dirigidas y sin dirigir, considerando solo aquellas que tienen soporte teórico. También se incluyen medidas de centralidad para redes ponderadas por el valor de las transacciones y para redes sin ponderar. El análisis de componentes principales se usa para identificar cuáles medidas de centralidad serán utilizadas para construir índices generales de centralidad. Esto implica que las medidas identificas como redundantes son excluidas de los índices generales debido a su baja contribución al criterio general de centralidad. Al igual que Joliffe (1972, 1973), la detección de las medidas redundantes que se logra usando el análisis de componentes principales, se verifica posteriormente mediante cuatro técnicas alternativas de reducción de datos. Resultados Las medidas identificadas como redundantes son eccentricity (ponderada y sin ponderar), closeness ponderada, y hub y authority ponderadas. Los índices generales calculados para cada infraestructura del mercado financiero permiten construir ordenamientos de sus participantes más centrales. Estos últimos son aquellos sobre los cuales se deben realizar las labores de monitoreo con mayor detenimiento debido a su potencial impacto en el sistema. Los índices generales de centralidad que se presentan en este documento tienen como propósito facilitar las labores de monitoreo que se realizan en el Banco de la República a los participantes de las infraestructuras de los mercados financieros

Levantamiento del velo corporativo : una mirada desde el gobierno corporativo y la teoría económica

Ilustraciones, gráficos, tablasEl presente trabajo de investigación tiene como objetivo llevar a cabo un análisis, desde la óptica de la teoría económica, del levantamiento del velo corporativo conceptualizado como uno de los mecanismos asociados al Gobierno Corporativo. Para ello, aborda la evolución del concepto de Gobierno Corporativo desde el ámbito económico. Posteriormente, desarrolla los conceptos desde las teorías de la Agencia y de la Nueva Economía Institucional. Finalmente, presenta un análisis aplicado del levantamiento del velo corporativo con base en las anteriores corrientes de pensamiento. A partir del análisis se puede concluir que el levantamiento del velo corporativo permite alinear intereses entre los administradores y proveedores del capital, reduciendo el riesgo asociado a la inversión y a su vez disminuyendo la compensación dada al administrador para incentivar su buen comportamiento. Así mismo, en escenarios con un marco jurídico institucional débil, se presentan otros mecanismos ex ante y ex post al proceso contractual.This research work aims to carry out an analysis, from the perspective of economic theory, of the lifting the corporate veil conceptualized as one of the mechanisms associated with Corporate Governance. This work traces the evolution of the Corporate Governance concept from the economic field. Subsequently, it develops the concepts from the Agency Theory and the New Institutional Economy. Finally, it presents an applied analysis of lifting the corporate veil based on the previous schools of thought. From the analysis, it can be concluded that the lifting the corporate veil allows the interests of managers and providers of capital to be aligned, reducing the risk associated with the investment and, in turn, reducing the compensation given to the manager to encourage good behavior. Likewise, other mechanisms are presented ex ante and ex post in the contractual process for scenarios with weak legal frameworks.MaestríaMagíster en Economí

Levantamiento del velo corporativo : una mirada desde el gobierno corporativo y la teoría económica

Ilustraciones, gráficos, tablasEl presente trabajo de investigación tiene como objetivo llevar a cabo un análisis, desde la óptica de la teoría económica, del levantamiento del velo corporativo conceptualizado como uno de los mecanismos asociados al Gobierno Corporativo. Para ello, aborda la evolución del concepto de Gobierno Corporativo desde el ámbito económico. Posteriormente, desarrolla los conceptos desde las teorías de la Agencia y de la Nueva Economía Institucional. Finalmente, presenta un análisis aplicado del levantamiento del velo corporativo con base en las anteriores corrientes de pensamiento. A partir del análisis se puede concluir que el levantamiento del velo corporativo permite alinear intereses entre los administradores y proveedores del capital, reduciendo el riesgo asociado a la inversión y a su vez disminuyendo la compensación dada al administrador para incentivar su buen comportamiento. Así mismo, en escenarios con un marco jurídico institucional débil, se presentan otros mecanismos ex ante y ex post al proceso contractual.This research work aims to carry out an analysis, from the perspective of economic theory, of the lifting the corporate veil conceptualized as one of the mechanisms associated with Corporate Governance. This work traces the evolution of the Corporate Governance concept from the economic field. Subsequently, it develops the concepts from the Agency Theory and the New Institutional Economy. Finally, it presents an applied analysis of lifting the corporate veil based on the previous schools of thought. From the analysis, it can be concluded that the lifting the corporate veil allows the interests of managers and providers of capital to be aligned, reducing the risk associated with the investment and, in turn, reducing the compensation given to the manager to encourage good behavior. Likewise, other mechanisms are presented ex ante and ex post in the contractual process for scenarios with weak legal frameworks.Magíster en EconomíaMaestrí

Apócope extrema e influencia castellanizante en la prosa gallega del siglo XIV

In this paper, we study the residual extreme apocope in medieval Galician texts in the context of the development of unstressed vowels in word-final position in this language. Following the line of thought initiated by García de Diego in 1909, later developed in works published in the 1980's, it has consistently been said that the so called extreme apocope was a rare phenomenon in Medieval Galician, with the exception of the type that supposedly appeared in certain texts, most of them translations of prose works of the 14th century. Through the exhaustive scrutiny that these cases have been subjected to in our work, we wish to show that this reservation is not justified and that it can be stated beyond any doubt that Medieval Galician was almost completely unaffected by this linguistic innovation.En este artículo estudiamos la residual apócope extrema de los textos gallegos medievales en el contexto del tratamiento dado en esta lengua a las vocales átonas en posición final de palabra. En la senda abierta por García de Diego en 1909, luego ampliada por trabajos publicados en la década de 1980, se ha venido diciendo hasta ahora que la llamada apócope extrema fue un fenómeno raro en la lengua gallega medieval, con la excepción de la que presuntamente aparecería en determinados textos, casi todos traducciones de obras en prosa del siglo XVI. Con el exhaustivo escrutinio que de estos casoshacemos en nuestro trabajo queremos demostrar que estas reservas son injustificadas y que se puede afirmar, ya sin restricciones, que el gallego medieval fue una lengua que vivió casi por completo ajena a esta innovación lingüística

Apócope extrema e influencia castellanizante en la prosa gallega del siglo XIV

In this paper, we study the residual “extreme apocope” in medieval Galician texts in the context of the development of unstressed vowels in word-final position in this language. Following the line of thought initiated by García de Diego in 1909, later developed in works published in the 1980's, it has consistently been said that the so called “extreme apocope” was a rare phenomenon in Medieval Galician, with the exception of the type that supposedly appeared in certain texts, most of them translations of prose works of the 14th century. Through the exhaustive scrutiny that these cases have been subjected to in our work, we wish to show that this reservation is not justified and that it can be stated beyond any doubt that Medieval Galician was almost completely unaffected by this linguistic innovation.En este artículo estudiamos la residual apócope extrema de los textos gallegos medievales en el contexto del tratamiento dado en esta lengua a las vocales átonas en posición final de palabra. En la senda abierta por García de Diego en 1909, luego ampliada por trabajos publicados en la década de 1980, se ha venido diciendo hasta ahora que la llamada “apócope extrema” fue un fenómeno raro en la lengua gallega medieval, con la excepción de la que presuntamente aparecería en determinados textos, casi todos traducciones de obras en prosa del siglo XVI. Con el exhaustivo escrutinio que de estos casoshacemos en nuestro trabajo queremos demostrar que estas reservas son injustificadas y que se puede afirmar, ya sin restricciones, que el gallego medieval fue una lengua que vivió casi por completo ajena a esta innovación lingüística

Functional two-way analysis of variance and bootstrap methods for neural synchrony analysis

[Abstract] Background: Pairwise association between neurons is a key feature in understanding neural coding. Statistical neuroscience provides tools to estimate and assess these associations. In the mammalian brain, activating ascending pathways arise from neuronal nuclei located at the brainstem and at the basal forebrain that regulate the transition between sleep and awake neuronal firing modes in extensive regions of the cerebral cortex, including the primary visual cortex, where neurons are known to be selective for the orientation of a given stimulus. In this paper, the estimation of neural synchrony as a function of time is studied in data obtained from anesthetized cats. A functional data analysis of variance model is proposed. Bootstrap statistical tests are introduced in this context; they are useful tools for the study of differences in synchrony strength regarding 1) transition between different states (anesthesia and awake), and 2) affinity given by orientation selectivity. Results: An analysis of variance model for functional data is proposed for neural synchrony curves, estimated with a cross-correlation based method. Dependence arising from the experimental setting needs to be accounted for. Bootstrap tests allow the identification of differences between experimental conditions (modes of activity) and between pairs of neurons formed by cells with different affinities given by their preferred orientations. In our test case, interactions between experimental conditions and preferred orientations are not statistically significant. Conclusions: The results reflect the effect of different experimental conditions, as well as the affinity regarding orientation selectivity in neural synchrony and, therefore, in neural coding. A cross-correlation based method is proposed that works well under low firing activity. Functional data statistical tools produce results that are useful in this context. Dependence is shown to be necessary to account for, and bootstrap tests are an appropriate method with which to do so

Unquenched flavor and tropical geometry in strongly coupled Chern-Simons-matter theories

We study various aspects of the matrix models calculating free energies and Wilson loop observables in supersymmetric Chern-Simons-matter theories on the three-sphere. We first develop techniques to extract strong coupling results directly from the spectral curve describing the large N master field. We show that the strong coupling limit of the gauge theory corresponds to the so-called tropical limit of the spectral curve. In this limit, the curve degenerates to a planar graph, and matrix model calculations reduce to elementary line integrals along the graph. As an important physical application of these tropical techniques, we study N=3 theories with fundamental matter, both in the quenched and in the unquenched regimes. We calculate the exact spectral curve in the Veneziano limit, and we evaluate the planar free energy and Wilson loop observables at strong coupling by using tropical geometry. The results are in agreement with the predictions of the AdS duals involving tri-Sasakian manifoldsComment: 32 pages, 7 figures. v2: small corrections, added an Appendix on the relation with the approach of 1011.5487. v3: further corrections and clarifications, final version to appear in JHE