Can fundamentals explain cross-country correlations of asset returns?.

Previous studies show that existing correlations between national returns are higher than correlations between the national growth rates of fundamental variables. This paper examines the ability of intertemporal asset pricing models to explain cross-country correlations of national returns. We find that when capital markets are assumed to be fully integrated, a simple intertemporal general equilibrium model is able to explain the observed co-variability of domestic asset returns but generates too little variability in those returns. Results improve considerably if a less restrictive version is employed. In that setting, both domestic variability and cross-country co-variability of returns are consistent with capital market integration.Asset pricing models; Cross-country correlations;

Can fundamentals explain cross-country correlations of asset returns?

Previous studies show that existing correlations between national returns are higher than correlations between the national growth rates of fundamental variables. This paper examines the ability of intertemporal asset pricing models to explain cross-country correlations of national returns. We find that when capital markets are assumed to be fully integrated, a simple intertemporal general equilibrium model is able to explain the observed co-variability of domestic asset returns but generates too little variability in those returns. Results improve considerably if a less restrictive version is employed. In that setting, both domestic variability and cross-country co-variability of returns are consistent with capital market integration.Publicad

Detecção e caracterização de defeitos internos por termografia infravermelha pulsada

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2014.A termografia pulsada (TP) é uma técnica promissora para a avaliação não-destrutiva de materiais. O protocolo de inspeção consiste na aplicação de um pulso térmico no espécime e monitorar a resposta térmica da superfície via radiação infravermelha (IV). Descontinuidades internas aparecem na sequência térmica como "hot spots" ou padrões térmicos irregulares, os quais são prodruzidos por alterações na taxa interna de difusão de calor. Apesar de ser uma das técnicas mais usadas e atrativas para a avaliação não-destrutiva, sua aplicação apresenta grandes desafios especialmente durante a inspeção de materiais anisotrópicos. 'Blurring', a perda de visibilidade devido aos efeitos da condução lateral de calor e a não-uniformidade produzida durante a excitação térmica representam as maiores limitações da TP. Esta tese é focada na otimização da inspeção por TP em laminados compósitos. Para tal propósito, foi desenvolvido um modelo termo-numérico para a análise da resposta térmica da material devido a presença de defeitos internos. Um estudo paramétrico foi desenvolvido com o objetivo de estudar o impacto do aquecimento não-uniforme, da intensidade da radiação e da geometria dos defeitos em vários parâmetros informativos da inspeção por TP. Uma análise das três técnicas mais usadas para o tratamento de sinais termográficos foi realizada e os seus desempenhos foram avaliados em função da relação sinal-ruído no ponto de maior contraste entre região com defeito e região sem defeito. Neste trabalho foi desenvolvida uma nova técnica de processamento e análise de imagens térmicas. A nova técnica - baseada no método de regressão dos mínimos quadrados parciais (PLSR) - decompõe a sequência térmica em variáveis latentes, permitindo assim a separação das diversas fontes de ruído que afetam a qualidade das imagens. A partir deste método de correlação foi desenvolvido um modelo empírico para a quantificação da profundidade e tamanho lateral dos defeitos empregando dados experimentais. Ambos os métodos - de tratamento de sinais e quantificação de defeitos - foram analisados e comparados com técnicas tradicionais, apresentando uma melhoria substancial na relação sinal-ruído e na precisão no processo de inversão de profundidade e forma dos defeitos.Abstract: Pulsed thermography (PT) is a novel and promissory technique for the nondestructive and evaluation (NDT&E) of materials. The inspection protocol consists in pulse heating the specimen while monitoring the resulting thermal response via infrared (IR) radiation. Subsurface discontinuities appear as transient hot spots or irregular thermal patterns in the thermogram sequence, which are produced by the alterations in the internal heat diffusion fluxes. In spite of being one of the most used and attractive methods for the NDT&E, its application still presents challenges specially when inspecting anisotropic materials. 'Blurring', the lost of defect visibility due to the effects of lateral heat conduction and the non-uniform heating produced during the application of the thermal excitation, represent the major drawbacks of PT. This thesis is focused on the optimization of the PT inspection of laminated composites. A thermal-numerical model is developed in order to analysis the thermal response of the material due to the presence of subsurface defects. A parametric study was performed aiming to study the impact of the effects of non-uniform heating, irradiation density and defects geometry on several informative variables of the PT inspection. An in-depth analysis of three of the most used PT sinal processing techniques was carried out and their performance was evaluated in terms of the signal-to-noise (SNR) at maximum signal contrast. In this work was also developed a new promissory technique for the processing and analysis of thermographic data. The new method - based on partial least squares regression (PLSR) - decomposes the thermal sequence into latent variables, allowing to separate several sources of noise affecting the quality of the images. From the statistical correlation method an empirical model was developed for the quantification of the depth and lateral size of defects using experimental data. Both methods - for the signal processing and for the inversion of depth and lateral size - were analyzed and compared with traditional techniques, achieving a substantial improvement in the signal-to-noise ratio and in the accuracy in the prediction results of depth and lateral size of the defects

Acuaterapia y lumbalgia mecánica

El siguiente documento presenta una serie de revisiones sobre dos aspectos bien definidos, la Lumbalgia y la Acuaterapia, los cuales poseen características especiales, la primera con sus factores de riesgo y manifestaciones y la segunda con sus propiedades benéficas que los pueden hacer tener una relación valida, esta relación no ha sido constatada de manera netamente objetiva ya que la información se encuentra de manera separada sobre ambos temas, sin encontrar investigaciones al respecto pues solo hay referencias de manera efímera. En este trabajo encontramos las definiciones sobre ambos conceptos dando a conocer sus características para que de esta manera se puedan discernir las relaciones mas relevantes, las cuales le pueden permitir a los profesionales del deporte y la recreación la creación de planes que ayuden a fomentar una practica como la Acuaterapia como medio rehabilitador y preventivo, además de generar inquietud en estos profesionales acerca de la realización de proyectos de investigación sobre este tema que puedan ampliar el conocimiento sobre los beneficios del medio acuático en una condición como la Lumbalgia la cual puede aparecer en cualquier momento sobre la población minimizando la calidad de vida no solo en el ámbito cotidiano sino también en el laboral, siendo en este ultimo punto en el que las entidades de salud podrían entrar a participar con un método como la Acuaterapia para la solución de este problema

Can fundamentals explain cross-country correlations of asset returns?

Previous studies show that existing correlations between national returns are higher than correlations between the national growth rates of fundamental variables. This paper examines the ability of intertemporal asset pricing models to explain crosscountry correlations of national returns. We find that when capital markets are assumed to be fully integrated, a simple intertemporal general equilibrium model is able to explain the observed co variability of domestic asset returns but generates too little variability in those returns. Results improve considerably if a less restrictive version is employed. In that setting, both domestic variability and cross country co variability of returns are consistent with capital market integration

Integrated Circuitry to Detect Slippage Inspired by Human Skin and Artificial Retinas

This paper presents a bioinspired integrated tactile coprocessor that is able to generate a warning in the case of slippage via the data provided by a tactile sensor. Some implementations use different layers of piezoresistive and piezoelectric materials to build upon the raw sensor and obtain the static (pressure) as well as the dynamic (slippage) information. In this paper, a simple raw sensor is used, and a circuitry is implemented, which is able to extract the dynamic information from a single piezoresistive layer. The circuitry was inspired by structures found in human skin and retina, as they are biological systems made up of a dense network of receptors. It is largely based on an artificial retina , which is able to detect motion by using relatively simple spatial temporal dynamics. The circuitry was adapted to respond in the bandwidth of microvibrations produced by early slippage, resembling human skin. Experimental measurements from a chip implemented in a 0.35-mum four-metal two-poly standard CMOS process are presented to show both the performance of the building blocks included in each processing node and the operation of the whole system as a detector of early slippage.Ministerio de Economía y Competitividad TEC2006-12376-C02-01Gobierno de España TEC2006- 1572

Integrated circuit interface for artificial skins

Artificial sensitive skins are intended to emulate the human skin to improve the skills of robots and machinery in complex unstructured environments. They are basically smart arrays of pressure sensors. As in the case of artificial retinas, one problem to solve is the management of the huge amount of information that such arrays provide, especially if this information should be used by a central processing unit to implement some control algorithms. An approach to manage such information is to increment the signal processing performed close to the sensor in order to extract the useful information and reduce the errors caused by long wires. This paper proposes the use of voltage to frequency converters to implement a quite straightforward analog to digital conversion as front end interface to digital circuitry in a smart tactile sensor. The circuitry commonly implemented to read out the information from a piezoresistive tactile sensor can be modified to turn it into an array of voltage to frequency converters. This is carried out in this paper, where the feasibility of the idea is shown through simulations and its performance is discussed.Gobierno de España TEC2006-12376-C02-01, TEC2006-1572

Can output explain the predictability and volatility of stock returns?.

This paper examines whether a general equilibrium asset pricing model can explain two important empirical regularities of asset returns, extensively documented in the literature: (i) returns can be predicted by a set of macro variables, and (ii) returns are very volatile. We derive a closed-form solution for the equilibrium asset pricing model that relates asset returns to output by using an approximate method proposed by Campbell (Am. Econ. Rev. 83 (1993) 487) and Restoy and Weil (W.P. NBER, No. 6611 (1998)). We obtain evidence on eight OECD economies using both quarterly and annual observations. Equilibrium models seem to fin fewer difficultie in explaining the volatility of returns than their predictability for general output processes. In the case of the US, the observed predictability and volatility of asset returns, for annual frequencies, are broadly compatible with the predictions of equilibrium models for a reasonableGeneralized isoelastic preferences; Asset returns; Real activity; Volatility;

Las sirenas medievales: aproximación literaria e iconográfica.

Sin resume

Proposta de arquitetura para provedores de serviços de redes fixas e móveis utilizando SDN OpenFlow

Tese (doutorado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2019.As redes de grande porte, como Provedores de Serviço, são arquiteturas robustas, capazes de dar suporte a grandes volumes de tráfego com características muito diferentes. Seus equipamentos dão suporte a cargas elevadas de processamento e ao mesmo tempo, são responsáveis por construir a lógica de roteamento e por encaminhar o tráfego. Por terem o controle implementado de forma distribuída e por serem construídas com equipamentos de um limitado número de fabricantes, estas redes apresentam limitações de controle e engenharia de tráfego, dificultando assim, a diferenciação entre os serviços que os diversos provedores fornecem. Adicionalmente, a inteligência da rede está oculta nos equipamentos, tornando as inovações muito lentas e amarradas aos interesses dos fabricantes. Como alternativa a este cenário, este trabalho propõe uma arquitetura de rede SDN-OpenFlow para redes móveis e redes de transporte que tenta solucionar os problemas previamente mencionados, bem como os inconvenientes da característica centralizadora que o OpenFlow possui. É apresentada uma arquitetura de rede OpenFlow robusta, capaz de dar suporte a tempos de resposta elevados e a quedas do Controlador, sem adição de tempos de espera no estabelecimento de novos fluxos e com significativa redução na carga submetida ao Controlador. Como prova de conceito, é implementado um protótipo utilizando o OpenvSwitch como software para a virtualização dos clientes OpenFlow, o Mininet para a criação da topologia e o Ryu como Controlador, todos com suporte OpenFlow 1.3. ou superior.Large scale networks, such as Service Providers, are robust architectures, capable of supporting large volumes of traffic with very different characteristics. Their network equipment have significant processing load, being responsible for building both a routing logic and a routing traffic at the same time. By having the network control implemented in a distributed manner and being built with a limited number of vendors, these networks have limitations of control and traffic engineering, hindering the differentiation between Service Providers. Additionally, the network intelligence is hidden in the network equipment, making the innovations very slow and conditioned to the vendors interests. As an alternative option, this work proposes an SDN-OpenFlow network architecture to transport and mobile networks that tries to improve the previously mentioned problems, and at the same time solves the arising difficulties related to the SDN network centralizing feature. With the proposed architecture, a robust OpenFlow network is created to support high Controller response times and Controller shut down, without additional delays in the creation of flows and with significant reduction of Controller’s load. A prototype has been constructed using Open vSwitch as a virtualization software for OpenFlow clients, Mininet for the topology construction and Ryu as the Controller, all with OpenFlow 1.3 support or higher