778 research outputs found

    Improving the accuracy and efficiency of time-resolved electronic spectra calculations: Cellular dephasing representation with a prefactor

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    Time-resolved electronic spectra can be obtained as the Fourier transform of a special type of time correlation function known as fidelity amplitude, which, in turn, can be evaluated approximately and efficiently with the dephasing representation. Here we improve both the accuracy of this approximation---with an amplitude correction derived from the phase-space propagator---and its efficiency---with an improved cellular scheme employing inverse Weierstrass transform and optimal scaling of the cell size. We demonstrate the advantages of the new methodology by computing dispersed time-resolved stimulated emission spectra in the harmonic potential, pyrazine, and the NCO molecule. In contrast, we show that in strongly chaotic systems such as the quartic oscillator the original dephasing representation is more appropriate than either the cellular or prefactor-corrected methods.Comment: submitte

    On Some Subtle Implications of the Choice of Numeraire for Monetary Policy in Developing Countries

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    Numeraire choice is often deemed a problem of purely analytical convenience. In this paper I show that there is more to numeraire selection than meets the eye for the formulation of monetary policy in countries with weak fiscal institutions. I show how (a) improper numeraire choice can dramatically overstate or understate Central Bank profits and (b) how this can threaten the ability of a Central Bank to keep inflation under control. I show point (a) in the context of Monte Carlo experiments calibrated for the Venezuelan economy and point (b) in an infinitely lived representative agent model that illustrates the problem of joint determination of the ideal level of foreign currency reserves and of the desired level of transfers of Central Bank profits to the Treasury when the objective is to eliminate the possibility of a hyperinflation

    Sliding mode predictive control for chemical proces with time delay

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    16th IFAC World Congress Praga (República Checa), 03/07/2005A design of a novel model predictive controller is presented. The proposed Sliding Mode Predictive Control (SMPC) algorithm combines the design technique of Sliding-Mode Control (SMC) with Model based Predictive Control (MPC). The SMPC showed a considerable robustness improvement with respect to MPC in the presence of time delay, and showed an enhanced ability to handle set point changes in a nonlinear process. Its robustness was evaluated using a robustness plot, its performance was judged using a single input single output nonlinear mixing tank process with variable time delay

    An analysis of sustainable marketing and how is managed through social media platforms.

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    This paper provides the analysis of sustainable marketing and how is managed through social platforms. Globalization and the rise of the digital era have allowed companies to put more effort in their sustainability practices. Therefore, it is important to know that consumers are smarter more demanding, thus, brands a creating relevant content to share their corporate share values. The data has been gathered from number of website’s articles, previous studies, books and videos. The current study has been an attempted to build knowledge and to understand the importance of how sustainable brands such as Weleda, Patagonia, Whole foods, McDonalds, Alo Yoga developed their strategies through social media to promote engagement to consumer.However, beyond creating engagement, brand need to consider other strategies though examine the customer journey. The findings of this research demonstrated that other sustainable brands create engagement by creating share value. Thus, relevant content can build a strong and long relationship between the brand and consumers. According to Cocking (2019) storytelling has become fundamental for this practice based on entertainment, learning, brand promotion and more. This evidence is shown by Kiepura (2017) with his example of Footprint Chronicles by Patagonia communicating their supply change problem with higher level of transparency. On the other hand, (USG) shown that creating the Hashtags #AloGivesWater and #cartgoals helped brands such as Alo yoga and Whole Food to connect with their audiences and build awareness. In overall, when planning a customer journey, sustainable brands are developing a model of experience economy. However, each interaction in the costumer journey will make a difference for the next step to satisfy consumer needs an understand consumer behaviours. As a result, brand can put more effort with their practices and build awareness between the consumers and the brand

    Evaluation of the influence of M-Learning on strengthening vocabulary for the Test Saber 11 - English in the I.E.M. Ciudad Eben Ezer of Fusagasugá.

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    Evaluation of the influence of M-Learning on strengthening vocabulary for the Test Saber 11 - English in the I.E.M. Ciudad Eben Ezer of FusagasugáEste proyecto de grado aplicado; busca demostrar el efecto de la implementación de actividades en línea como un enfoque de la estrategia pedagógica M-Learning, con estudiantes de uno de los décimos grados (10-01) de la Institución Educativa Municipal Ciudad Eben Ezer de Fusagasugá. Mediante la implementación de actividades de práctica educativa y digital en dispositivos móviles, en las cuales los estudiantes interactúan con diversos contenidos que enriquecen su experiencia de aprendizaje de inglés. Las actividades tienen un enfoque de adquisición de vocabulario para mejorar la comprensión de lectura y busca demostrar que los estudiantes que participan en este proceso de aprendizaje mejorarán las habilidades necesarias para enfrentar el examen "Sabre 11".This applied grade project; seeks to demonstrate the effect of the implementation of online activities as an approach to the M-Learning pedagogical strategy, with students from one of the tenth grades (10-01) of the Municipal Educational Institution Ciudad Eben Ezer de Fusagasugá. Through the implementation of educational and digital practice activities on mobile devices, in which students interact with various contents that enrich their English learning experience. The activities have a vocabulary acquisition approach to improve reading comprehension and It seeks to demonstrate that students participating in this learning process will enhance the necessary skills to face the test "Saber 11"

    Thermodynamics of firms' growth

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    The distribution of firms' growth and firms' sizes is a topic under intense scrutiny. In this paper we show that a thermodynamic model based on the Maximum Entropy Principle, with dynamical prior information, can be constructed that adequately describes the dynamics and distribution of firms' growth. Our theoretical framework is tested against a comprehensive data-base of Spanish firms, which covers to a very large extent Spain's economic activity with a total of 1,155,142 firms evolving along a full decade. We show that the empirical exponent of Pareto's law, a rule often observed in the rank distribution of large-size firms, is explained by the capacity of the economic system for creating/destroying firms, and can be used to measure the health of a capitalist-based economy. Indeed, our model predicts that when the exponent is larger that 1, creation of firms is favored; when it is smaller that 1, destruction of firms is favored instead; and when it equals 1 (matching Zipf's law), the system is in a full macroeconomic equilibrium, entailing "free" creation and/or destruction of firms. For medium and smaller firm-sizes, the dynamical regime changes; the whole distribution can no longer be fitted to a single simple analytic form and numerical prediction is required. Our model constitutes the basis of a full predictive framework for the economic evolution of an ensemble of firms that can be potentially used to develop simulations and test hypothetical scenarios, as economic crisis or the response to specific policy measures

    An Intelligent Transportation System: the Quito City Case Study

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    Managing traffic in a large city has become a topic of great interest in both politics and science. The costs of poor traffic management have been quantified as losses equal to millions of dollars, not counting the unquantifiable value of the time that a person loses in traffic jams. Intelligent transport systems (ITS) offer a set of innovative solutions specific to the management of different modes of transport. This article focuses on the development of an ITS for the city of Quito that allows smart decision-making to direct heavy haul transporters that want to enter the city via one of its main access routes. Technologies such as Sensor Web Enablement (SWE), in association with the Message Queuing Telemetry Transport (MQTT) communication protocol, facilitate the development of a vehicular management platform/system capable of sending notifications in real-time and issuing instructions to drivers regarding traffic delays along routes, average speeds, etc. The system supports a network of heterogeneous sensors accessible through the web. It can integrate any device that uses HTTP protocol. Time interval and location range testing have been undertaken to refine the accuracy of the system and make it adaptable to any geographic situation. The system allows communicate with the server through MQTT or through web services, using technologies such as: MongoDB and GeoJSON. One of the most relevant results is that the degree of accuracy of the system is within appropriate ranges when compared to commercial applications such as Google Maps and Waze

    Robot escalador para mantenimiento y limpieza de edificios

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    Se expone una breve descripción del diseño e implementación de una plataforma móvil como herramienta de investigación en modos de caminar de robots cuadrúpedos, y que permita además el estudio de métodos de locomoción para robots escaladores

    Triagem de hidrocarbonetos em bactérias isoladas de amostras da Antártida

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    Anais do V Encontro de Iniciação Científica e I Encontro Anual de Iniciação ao Desenvolvimento Tecnológico e Inovação – EICTI 2016 - 05 e 07 de outubro de 2016 – Sessão BiológicasVive-se um momento em que se faz necessário o aumento da produção energética no globo. Este quadro leva à exploração dos recursos naturais. Diante disso, buscam-se fontes renováveis de energia. Uma dessas alternativas são os chamados micro-organismos psicrofílicos. Estes apresentam características singulares, sendo capazes de sobreviver às baixas temperaturas de biomas como o continente Antártico. Existem estudos que procuram obter células microbianas com o intuito de sintetizar hidrocarbonetos ou outros compostos que derivam de hidrocarbonetos no propósito de utilizá-los como biocombustíveis. Esta opção apresentaria uma possibilidade de produção de combustíveis tidos como ecologicamente corretos, uma substituição aos combustíveis derivados do petróleo – fato que torna essas fontes de energia a partir de sistemas microbianos alternativas emergentes. O presente trabalho utilizou micro-organismos psicrofílicos ou psicrotolerantes isolados de amostras do continente Antártico com o objetivo de realizar a prospecção de hidrocarbonetos com potencial de utilização em processos de produção de biocombustíveis
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