Start-up of virtual synchronous machine: methods and experimental comparison

A modern grid is smarter mainly in the advance in information and communication technologies, while the power processing mechanism does not make a big difference. To make a modern grid smarter, the grid control should be improved to process the power in a smarter way. Therefore, it is easily foreseen that virtual synchronous machines, which emulates the synchronous machines based on power converters, may have big potentials in a future energy internet. This paper uses the Synchronous Power Controller with emulated and improved synchronous machine characteristics for renewable generation systems and proposes two start-up strategies. The proposed strategies are explained in detail, verified and compared by experimental results.Peer ReviewedPostprint (published version

The impact of taxes on income mobility

This paper investigates how taxes affect relative mobility in the income distribution in the US. Household panel data drawn from the PSID between 1967 and 1996 is employed to analyse the relationship between marginal tax rates and the probability of staying in the same income decile. Exogenous variation in marginal tax rates is identified by using counterfactual rates based on legislated changes in the tax schedule. I find that higher marginal tax rates reduce income mobility. An increase in one percentage point in marginal tax rates causes a decline of around 0.8% in the probability of changing to a different income decile. Tax reforms that reduce marginal rates by 7 percentage points are estimated to account for around a tenth of the average movements in the income distribution in a year. Additional results suggest that the effect of taxes on income mobility differs according to the level of human capital and that it is particularly significant when considering mobility at the bottom of the distribution

Los Intangibles en el Diseño de Sistemas de Ayuda a la Decisión.

El interés por los intangibles empezó a partir de la crisis reputacional de finales de siglo XX, que tuvo un impacto tremendo en Estados Unidos. Los casos de Enron, Tyco, Ahold, y Arthur Andersen pusieron de manifiesto la vulnerabilidad a los riesgos reputacionales. Fuera de Estados Unidos, el caso de la compañía Parmalat consiguió que los empresarios de todo el mundo se dieran cuenta por primera vez de que la reputación mal gestionada puede hacer desaparecer una empresa. Hoy sabemos que más del 80 % del valor total de una organización reside en sus recursos y activos intangibles y, por este motivo, estos activos se han convertido en el asunto de mayor relevancia en la agenda de los principales ejecutivos españoles. No solo porque la buena reputación atrae consumidores, capital, talento, facilita la internacionalización y permite alinear los intereses y voluntades de toda la organización para conseguir los objetivos de negocio, sino porque la gestión integrada e integral de los intangibles es la única ruta posible para alcanzar una diferenciación sostenible en el tiempo generadora de márgenes superiores y al mismo tiempo un capital de confianza con los grupos de interés que asegura conseguir y mantener las licencias para operar. La buena gestión de los intangibles asegura por tanto, y en último término, la excelencia empresarial.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The impact of taxes on income mobility

En este documento se investiga cómo los impuestos afectan a la movilidad relativa en la distribución de la renta en Estados Unidos. En particular, este estudio utiliza datos de hogares procedentes del PSID entre 1967 y 1996 para analizar la relación entre cambios en los tipos marginales y la probabilidad de permanecer en el mismo decil de renta. La estrategia de identificación se basa en explotar variación exógena en los tipos marginales construyendo unos tipos contrafactuales basados en cambios legislativos en las escalas de gravamen. Se encuentra que tipos marginales más altos reducen la movilidad entre distintos tramos de renta. Un incremento de 1 punto porcentual en el tipo marginal causa una reducción de alrededor de 0,8 puntos porcentuales en la probabilidad de cambiar a otro decil de renta. De esta forma, una reforma fiscal que reduce los tipos marginales en 7 puntos porcentuales podría explicar alrededor de un décimo de la probabilidad media de que un hogar experimente cambios en su posición en la distribución de la renta. Algunos resultados adicionales sugieren que el efecto de los impuestos en la movilidad en la renta difiere según el nivel de capital humano y que es particularmente significativo cuando se analiza la movilidad en la parte baja de la distribución de la rentaThis paper investigates how taxes affect relative mobility in the income distribution in the US. Household panel data drawn from the PSID between 1967 and 1996 is employed to analyse the relationship between marginal tax rates and the probability of staying in the same income decile. Exogenous variation in marginal tax rates is identified by using counterfactual rates based on legislated changes in the tax schedule. I find that higher marginal tax rates reduce income mobility. An increase in one percentage point in marginal tax rates causes a decline of around 0.8 percentage points in the probability of changing to a different income decile. Tax reforms that reduce marginal rates by 7 percentage points are estimated to account for around a tenth of the average movements in the income distribution in a year. Additional results suggest that the effect of taxes on income mobility differs according to the level of human capital and that it is particularly significant when considering mobility at the bottom of the distributio

Is fiscal policy more effective in uncertain times or during recessions?

En este documento se estima el impacto de cambios exógenos en el gasto público sobre la actividad económica durante períodos de alta y baja incertidumbre, y durante períodos de expansiones y recesiones. Se encuentra que el efecto del gasto público sobre el PIB es de mayor magnitud durante períodos expansivos que durante recesiones, y más grande durante períodos de baja incertidumbre que durante períodos de turbulencia económica. Los resultados obtenidos sugieren que la confianza sobre las perspectivas económicas desempeña un papel relevante a la hora de explicar este efecto diferencial de la política fiscalThis paper estimates the impact of government spending shocks on economic activity during periods of high and low uncertainty and during periods of boom and recession. We find that government spending shocks have larger impacts on output in booms than in recessions and larger impacts during tranquil times than during uncertain times. The results suggest that confidence plays an important role in explaining this differential impac

Multi-terminal HVDC grids with inertia mimicry capability

The high-voltage multi-terminal dc (MTDC) systems are foreseen to experience an important development in the next years. Currently, they have appeared to be a prevailing technical and economical solution for harvesting offshore wind energy. In this study, inertia mimicry capability is added to a voltage-source converter-HVDC grid-side station in an MTDC grid connected to a weak ac grid, which can have low inertia or even operate as an islanded grid. The presented inertia mimicry control is integrated in the generalised voltage droop strategy implemented at the primary level of a two-layer hierarchical control structure of the MTDC grid to provide higher flexibility, and thus controllability to the network. Besides, complete control framework from the operational point of view is developed to integrate the low-level control of the converter stations in the supervisory control centre of the MTDC grid. A scaled laboratory test results considering the international council on large electric systems (CIGRE) B4 MTDC grid demonstrate the good performance of the converter station when it is connected to a weak islanded ac grid.Peer ReviewedPostprint (author's final draft

Portuguese contraband and the closure of the Iberian markets, 1621-1640. The economic roots of an anti-Habsburg sentiment

[EN] This article explores the extent of the trade in contraband goods apprehended in the ports of Portugal between 1621 and 1640. Such illegal activity is seen as the response of local authorities and traders seeking to neutralize the damage that they suffered due to the lack of legal trade, arising in part from Philip IV’s foreign policy. The paper also includes some evidence that shows how the erosion of the Portuguese economy became a key element in arousing the anti-Spanish feeling that ultimately led to the 1640 rebellion.The research for this paper was funded by the Spanish Ministry of Education and Science, Project I+D HUM2006-06413/HISTPeer reviewe

Patient registries in rare diseases: identifying the specific issues and potential solutions to improve quality data and outcomes = Registros de pacientes en enfermedades raras: identificación de problemas específicos y soluciones potenciales para mejorar la calidad de los datos y resultados

285 p.Esta tesis ha sido realizada con el objetivo de identificar las necesidades no cubiertas en las guías sobre registros de pacientes y ofrecer posibles soluciones a estas cuestiones, para ayudar a mejorar la calidad y la sostenibilidad en futuros registros de enfermedades raras. La experiencia adquirida en primera persona al liderar uno de los mayores registros de enfermedades raras, desde su concepción hasta la publicación de los resultados, ha permitido una comprensión profunda de este tipo de registros de pacientes, sus problemas específicos y las medidas pertinentes que deben tomarse para evitarlos. = This thesis was conducted with the objective to identify the unmet needs in the guidance on rare disease patient registries and offer potential solutions to these issues, to help to improve the quality and sustainability in the future registries in rare diseases. Gathering a first hand experience while leading one of the largest rare disease registry, from inception to publication, has offered intensive understanding of rare diseases registries, its specific concerns and related measures to be taken to avoid these issues