4,648 research outputs found

    Towards Robust Deep Reinforcement Learning for Traffic Signal Control: Demand Surges, Incidents and Sensor Failures

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    Reinforcement learning (RL) constitutes a promising solution for alleviating the problem of traffic congestion. In particular, deep RL algorithms have been shown to produce adaptive traffic signal controllers that outperform conventional systems. However, in order to be reliable in highly dynamic urban areas, such controllers need to be robust with the respect to a series of exogenous sources of uncertainty. In this paper, we develop an open-source callback-based framework for promoting the flexible evaluation of different deep RL configurations under a traffic simulation environment. With this framework, we investigate how deep RL-based adaptive traffic controllers perform under different scenarios, namely under demand surges caused by special events, capacity reductions from incidents and sensor failures. We extract several key insights for the development of robust deep RL algorithms for traffic control and propose concrete designs to mitigate the impact of the considered exogenous uncertainties.Comment: 8 page

    Comunicación intern a en las instituciones: herramient a práctica de ayuda al cambio de turno

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    Introdução: A comunicação interna dentro da organização, seja ela interpessoal, grupal ou intergrupal, deve envolver todos os colaboradores de forma a pôr em comum a missão, os valores, os princípios operativos e os padrões de comportamento que geram o desenvolvimento organizacional e a motivação. Desenvolvimento: A passagem de turno em enfermagem é um momento fundamental de aprendizagem e de transmissão de informações relativas ao doente. A informação fornecida na passagem de turno deve ser objetiva e atualizada, tendo sempre em conta os princípios ético-deontológicos e uma linguagem técnica sobre os cuidados prestados ao doente, resultantes da aplicação de uma metodologia científica e de estratégias de reflexão. De forma a facilitar a transmissão de informação, pretendemos com este trabalho realizar um instrumento prático, neste caso escrito, de auxílio á passagem de turno. Para tal foi realizado um estudo junto de uma amostra de enfermeiros aos quais foi aplicado um Questionário de Colheita de Dados. Conclusões: A utilização de um instrumento de suporte à passagem de turno constitui um dos pilares do aperfeiçoamento dos cuidados de enfermagem.Introduction: The internal communication inside the organization, whether is interpersonal, group or intergroup, must involve all the collaborators in order the mission, values, operative principles and the behaviour patterns be common, to generate the organizational development and motivation. Development: The shift change in nursing is a fundamental moment of learning and information transmission regarding the patient. The information given on the shift change must be objective and updated, always considering the ethical-deontological principles and a technical language about the care given to the patient, resulting of the application of a scientific methodology and reflexion strategies. In order to ease the information transmission, we intent, with this work, to do a practical instrument, in this case a written one, to aid the shift changing. For this, it was performed a study in a sample of nurses to whom was applied a Data Collection Questionnaire. Conclusions: The use of a support tool for the shift change is one of the pillars of the improvement of nursing care.Introducion: La comunicación interna dentro de una organización, ya sea interpersonal, de grupo o entre grupos, debe involucrar a todos los colaboradores con el fin de tener en común la misma misión, valores, principios de funcionamiento y patrones de comportamiento que generan un adecuado desarrollo de la organización y una adecuada motivación. Desarrollo: El cambio de turno en enfermería es un momento crítico del aprendizaje y la transmisión de información relacionada con el paciente. La información proporcionada en el cambio de turno debe ser objetiva y actualizada, teniendo en cuenta los principios éticos y deontológicos y el lenguaje técnico de la atención prestada al paciente, fruto de la estrategia y metodología científica realizada. Con el fin de facilitar la transmisión de información, con este trabajo pretendemos crear una herramienta práctica, en este caso escrita, que ayude en el cambio de turno. Para ello, fue realizado un estudio con un número de enfermeras a las que se les dio un Cuestionario de Recogida de Datos. Conclusiones: El uso de una herramienta de apoyo para el cambio de turno es uno de los pilares de la mejora de la atención de enfermería.info:eu-repo/semantics/publishedVersio

    Do modernismo em William Faulkner : «As I Lay Dying»

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    This article offers a reading of As I Lay Dying which takes into account the historical and cultural context of William Faulkner’s narrative fiction. The focus is both on the author’s tendency to see his fiction as shadowed by the repressed myths and stories of his (Southern, Victorian) culture and on the refracted techniques of Modernism, to which he was introduced as a young man. As this study attempts to demonstrate, it was by linking the classic Southern romance with the modern sense of experimental form, by merging a deep-seated sense of regional history with an awareness of the fracture of historical time, that Faulkner became a major novelist, drawn to write in a way that was as old as storytelling and, at the time, as new as Cubism. As a matter of fact, it is in the works of the end of the Twenties and Thirties, after having invented Yoknapatawpha County as a fictional setting for his fiction, that we can feel the writer’s experimental power at full force, for example in The Sound and the Fury (1929) and As I Lay Dying (1930). The latter is discussed as the story of the funeral journey of a clan of poor whites, which is told through fifty-nine interior monologues, reflections on living and dying, a moving wagon, and the complex and grotesque panorama of life surrounding it. This paper also argues for Addie Bundren as the absent presence in the novel, a mother and wife who obsesses the other members of the family, someone who tends to exist for her creator outside the coventional parameters of language. After having systematized Addie’s dichotomy between words and deeds and its projection on the ‘streamof-consciousness’ of the Bundrens, a more detailed analysis of the main characters’ thoughts, actions and language is undertaken, while the mother’s soliloquy is explored as a 'provincial' (i.e., from the Yoknapatawpha province) version of a modernist manifesto

    A portrait of the indian woman as ghost dancer : mother Sioux in Paul Auster's Mr. Vertigo

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    This paper argues that Paul Auster, the American writer whose novéis in the 1980´s and 1990´s are (auto-) reflexive fictions about fiction, presents a portrait of an artist as a young man, and a reflection about the nature of artistic creativity in Mr Vertigo

    Early Diagenesis of Lower Pliensbachian Sediments from the Algarve Basin (Portugal): Characterisation and Relation with Tectonic Evolution

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    The Lower Jurassic (Lower Pliensbachian) sedimentary record of the western end of the Algarve Basin (Portugal) is made of decimetric thick layers of limestone and dolomitized limestone with chert nodules and inter-layered chert beds. Most of the observable lithologies are the product of an early diagenetic evolution and the original lithological content of the formation included limestones, marls and calciclastic limestones. In this area the sedimentation was controlled by the tectonic stretching responsible for the evolution of the Algarve Basin, as well as by short-lived events of tectonic inversion. These episodes of tectonic inversion were responsible for the some uplift with the development of unconformities, sometimes with erosional surfaces separating the different sedimentary packages. The early diagenesis affecting the Lower Pliensbachian sediments is characterized by: (i) a mechanical event controlled by the syn-sedimentary stretching, responsible for the development of calciclastic dikes and nodules alignements; (ii) the substitution of the carbonates from the most permeable calciclastic limestone layers by silica, leading to the development of the observed cherts; (iii) the dolomitization of the preserved limestones; and (iv) the infilling of joints and normal fault planes by silica-rich fluids leading to the development of quartz veins. This set of diagenetic transformations took place before the Upper Pliensbachian which lacks the evidences of their occurrence. The whole-rock geochemical data of the carbonate and siliceous sediments of the Lower Pliensbachian revealed some affinities between both lithological types namely the lack of Ce anomalies and the presence of La anomalies in the REE patterns of all samples. The similarities between the carbonate lithologies which diagenetic evolution is marked by the replacement of calcite by dolomite and the siliceous sediments derived from the replacement of calcite by quartz establish a chemical connection between the two sets of rocks. This connection can be interpreted as a testimony of a common primary precursor for both lithological groups or as a testimony of a common character of the diagenetic fluids which interacted with the original sediments. The dolomitization changed the Sr isotopic signature increasing the 87Sr/86Sr ratios from 0.7073 in the unchanged limestone to a maximum value of 0.7113 in the dolomitized samples. This strong increase together with the 13C/12C and 18O/16O values support an external origin for the dolomitizing fluids. A possible origin for the diagenesis is meteoric water coming into the basin after weathering the country rocks. The hydrologic regime in the basin certainly underwent important changes during the uplift events associated to the mentioned tectonic inversion episodes and uplift allowing for input of water from land

    Early Diagenesis of Lower Pliensbachian Sediments from the Algarve Basin (Portugal): Characterisation and Relation with Tectonic Evolution

    Get PDF
    The Lower Jurassic (Lower Pliensbachian) sedimentary record of the western end of the Algarve Basin (Portugal) is made of decimetric thick layers of limestone and dolomitized limestone with chert nodules and inter-layered chert beds. Most of the observable lithologies are the product of an early diagenetic evolution and the original lithological content of the formation included limestones, marls and calciclastic limestones. In this area the sedimentation was controlled by the tectonic stretching responsible for the evolution of the Algarve Basin, as well as by short-lived events of tectonic inversion. These episodes of tectonic inversion were responsible for the some uplift with the development of unconformities, sometimes with erosional surfaces separating the different sedimentary packages. The early diagenesis affecting the Lower Pliensbachian sediments is characterized by: (i) a mechanical event controlled by the syn-sedimentary stretching, responsible for the development of calciclastic dikes and nodules alignements; (ii) the substitution of the carbonates from the most permeable calciclastic limestone layers by silica, leading to the development of the observed cherts; (iii) the dolomitization of the preserved limestones; and (iv) the infilling of joints and normal fault planes by silica-rich fluids leading to the development of quartz veins. This set of diagenetic transformations took place before the Upper Pliensbachian which lacks the evidences of their occurrence. The whole-rock geochemical data of the carbonate and siliceous sediments of the Lower Pliensbachian revealed some affinities between both lithological types namely the lack of Ce anomalies and the presence of La anomalies in the REE patterns of all samples. The similarities between the carbonate lithologies which diagenetic evolution is marked by the replacement of calcite by dolomite and the siliceous sediments derived from the replacement of calcite by quartz establish a chemical connection between the two sets of rocks. This connection can be interpreted as a testimony of a common primary precursor for both lithological groups or as a testimony of a common character of the diagenetic fluids which interacted with the original sediments. The dolomitization changed the Sr isotopic signature increasing the 87Sr/86Sr ratios from 0.7073 in the unchanged limestone to a maximum value of 0.7113 in the dolomitized samples. This strong increase together with the 13C/12C and 18O/16O values support an external origin for the dolomitizing fluids. A possible origin for the diagenesis is meteoric water coming into the basin after weathering the country rocks. The hydrologic regime in the basin certainly underwent important changes during the uplift events associated to the mentioned tectonic inversion episodes and uplift allowing for input of water from land

    The effects of market orientation and cooperation on performance

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    Cooperation in the marketing channel has conquered an increasingly prominent role in contemporary business strategy and tactics and has been considered a key driver of value for partnering companies. Currently is undesirable for organizations to operate alone, because they are under pressure to reduce costs, improve service quality and share risks. As such, companies are pressured to Cooperate more toward the same goals in order to remain competitive. The present study aims at investigating if Market oriented companies have a better Performance when they Cooperate with other companies in the context of marketing channel. The study considered Market orientation and Cooperation in order to assess their effects on Performance. The research setting is Portugal and the population consisted of executive board decision makers. The data comprises 221 responses through an e-mail survey. Our findings confirmed that Market orientation and Cooperation have a great impact on Performance. However some exceptions were found regarding Competitor orientation and Information sharing, whose impacts were no significant. Although companies analyzing their competitors’ activities and are willing to collaborate and accommodates the customers’ needs, they reveal reluctance in internally disseminating information about their competitors, and in sharing with their partners, technical, tactical and strategic information unless this is needed for success. Trust is valuable in alliances because, in different degrees, each company has to rely on their partner. It is possible that if companies practice more openly Information sharing they might obtain a better Performance. Consequently, these findings build an important bridge between Market orientation and Cooperation, suggesting that companies can to be more competitive and therefore improve their Performance.A Cooperação no campo do Marketing tem vindo a ocupar um lugar de destaque reforçado pela actual envolvente em crescente mudança, assumindo um papel cada vez mais relevante nas estratégias comerciais. Actualmente é inviável às organizações operarem sozinhas, pressionadas para reduzir custos, melhorar a qualidade do serviço e partilhar riscos, estando por isso empenhadas em cooperar na direcção dos mesmos objectivos de modo a serem competitivas. O presente estudo tem como objectivo, investigar se as empresas orientadas para o mercado revelam melhor Desempenho quando Cooperam com outras empresas. A investigação teve lugar em Portugal, com uma amostra de 221 respostas ao questionário. Destacamos na pesquisa exploratória a confirmação de que a Orientação para o mercado e a Cooperação tem um forte impacto no Desempenho da empresa, contudo identificamos na Orientação para o competidor e na Partilha de informação algumas excepções. Embora as empresas analisem e acompanhem as actividades dos concorrentes, e, desejam colaborar e adaptar-se às necessidades dos clientes, revelam alguma relutância na partilha interna da informação referente aos concorrentes, e na disponibilização da informação técnica, táctica ou estratégica junto dos clientes, salvo se for estritamente necessário para o sucesso. Apesar desta resistência em Partilhar informação, a Confiança apresenta-se especialmente valiosa para as alianças, porque, embora em diferentes níveis, cada empresa tem de confiar no seu parceiro. Possivelmente, se as empresas Partilharem mais informação, podem obter melhor Desempenho. Consequentemente, estes achados podem construir uma ponte importante entre a Orientação para o Mercado e a Cooperação permitindo às empresas melhor Desempenho

    The performance of german equity mutual funds

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    Dissertação de mestrado em FinançasThis study evaluates the performance of German mutual funds that invest in the domestic, European and global market, using unconditional and conditional models of performance evaluation. The dataset includes 159 German funds over the period of January 2010 to December 2018. The results suggest that mutual fund managers investing domestically have a neutral performance, whereas those investing internationally show negative performance. These results are consistent with the existence of a distance effect, since fund managers who invest locally perform better than those who invest in foreign markets. Overall, the results confirm that multi-factor models, with the inclusion of additional risk factors, are better than single models in explaining mutual fund returns. In addition, the use of the full conditional model with time-varying alphas and betas increases the explanatory power of the models.Este estudo avalia o desempenho de fundos de investimento alemães que investem no mercado doméstico, Europeu e global, usando modelos não condicionais e condicionais de avaliação de desempenho. A amostra inclui 159 fundos alemães no período de Janeiro de 2010 a Dezembro de 2018. Os resultados sugerem que os gestores de fundos domésticos têm um desempenho neutro, ao passo que os gestores de fundos internacionais têm um desempenho negativo. Estes resultados são consistentes com a existência de efeito distância, uma vez que os gestores de fundos que investem localmente têm um desempenho melhor do que aqueles que investem em mercados mais longínquos. No geral, os resultados confirmam que modelos multi-fatores, com a inclusão de fatores de risco adicionais, são superiores aos modelos de um fator na explicação das rendibilidades dos fundos de investimento. Além disso, observa-se que o uso do modelo condicional completo com alfas e betas variáveis no tempo aumenta o poder explicativo dos modelos
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