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1 to 34 of 34 results
  • Modification of the Perrine-baum diagram to improve the calculation of high-voltage transmission lines

     Horta Bernus, Ricard; Rosas Casals, Marti
    IEEE transactions on education
    Date of publication: 2013-08
    Journal article

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  • El canvi climàtic i les seves repercusions econòmiques en les estacions d'esquí dels Pirineus

     Jover Comas, Eric; Pons Pons, Marc; Rosas Casals, Marti
    Date of publication: 2013-10-01
    Book chapter

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  • The evolutionary ecology of technological innovations

     Solé, Ricard; Valverde, Sergi; Rosas Casals, Marti; Kauffman, Stuart; Farmer, Doyne; Eldredge, Niles
    Complexity
    Date of publication: 2013-03-01
    Journal article

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    Technological evolution has been compared to biological evolution by many authors over the last two centuries. As a parallel experiment of innovation involving economic, historical, and social components, artifacts define a universe of evolving properties that displays episodes of diversification and extinction. Here, we critically review previous work comparing the two types of evolution. Like biological evolution, technological evolution is driven by descent with variation and selection, and includes tinkering, convergence, and contingency. At the same time, there are essential differences that make the two types of evolution quite distinct. Major distinctions are illustrated by current specific examples, including the evolution of cornets and the historical dynamics of information technologies. Due to their fast and rich development, the later provide a unique opportunity to study technological evolution at all scales with unprecedented resolution. Despite the presence of patterns suggesting convergent trends between man-made systems end biological ones, they provide examples of planned design that have no equivalent with natural evolution

  • Data exploration

     Rosas Casals, Marti
    Date of publication: 2012
    Book chapter

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  • Smart Grids and Complexity Science

     Rosas Casals, Marti
    Date of publication: 2012-12-31
    Book chapter

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  • On the difficulty (and success) of correlating empirical data and (extended) topological measures in power grid networks

     Luo, Lingen; Bompard, Ettore; Rosas Casals, Marti
    International Conference on Critical Information Infrastructure Security
    Presentation's date: 2012-09-18
    Presentation of work at congresses

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    Power grids have entered the complex networks realm for quite a long time now. Their structure (i.e., topology) and dynamics have been thoroughly studied and many topological measures have been used in order to classify them, evaluate their behavior in terms of robustness or model their dynamic response to malfunctions. Generally speaking, results have been mainly theoretical and sound correlations between real grid’s dynamical behavior (i.e., malfunctions and major events) and any of the mentioned before measures have not yet been found. In recent years, though, new extended topological measures have been used to quantify the ability of a network in sustaining its basic functions. In this paper we present a first attempt to correlate these new measures with real malfunction data for some major European power transmission grids. Similar behavior is found, in terms of robustness to selected attacks to buses, between different networks. This is measured by means of extended topological indexes electrically better defined. These behaviors can be (weakly) correlated with similar probability distributions of major events, identifying similar dynamical response among topologically similar grids. This would raise hopes in finding a more meaningful and significant linkage between structural measures and the real dynamical output (i.e., major events) of a grid.

  • A Perspective overview of topological approaches for vulnerability analysis of power transmission grids

     Bompard, Ettore; Pons, Enrico; Luo, Lingen; Rosas Casals, Marti
    International Conference on Critical Information Infrastructure Security
    Presentation's date: 2012-09-18
    Presentation of work at congresses

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  • De colapsos y continuidades. Una valoración conceptual del estudio de sociedades en transición  Open access

     Delgado Raack, Selina; Rosas Casals, Marti
    Sostenible?
    Date of publication: 2012
    Journal article

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    El proceso de estudio de los fenómenos de orden social o natural requiere de categorías analíticas específicas como herramientas destinadas a describir la realidad. Una de las categorías comúnmente utilizadas en la bibliografía es la de colapso. Este artículo persigue dos objetivos fundamentales que convergen en la intención de matizar la definición de este término: (1) se realiza una revisión de su uso a través de la bibliografía que trata casos concretos de sociedades pasadas cuyo destino ha sido directamente relacionado con este fenómeno y (2) se presenta el caso de estudio del colapso de la sociedad argárica, sita en el sudeste peninsular. Finalmente se realiza un ejercicio de correspondencia entre los aspectos destacados en el caso de estudio y los rasgos postulados en la bibliografía acerca del concepto de colapso.

    El procés de l'estudi dels fenòmens de l'ordre social o natural requereix de categories analítiques especifiques, com eines destinades a descriure la realitat. Una de les categories comunament utilitzades en la bibliografia és el del col·lapse. Aquest article, persegueix dos objectius: (1) es realitza una revisió del seu ús a través de la bibliografia que tracta casos concrets de societats passades en el que el seu destí ha estat directament relacionat amb aquest fenomen i (2) es presenta el cas d'estudi del col·lapse de la societat argàrica, situat en el sud-est peninsular. Finalment, es realitza un exercici de correspondència entre els aspectes destacats en el cas d'estudi i el trets postulats en la bibliografia sobre el concepte de col·lapse.

    The process of studying social or natural phenomena requires specific analytical categories that serve as tools to describe reality. One of the commonly used categories among the literature is collapse. This article has two main objectives that converge on the intention to refine the definition of the term: (1) a review of its use through the literature dealing with specific instances of past societies whose fate has been directly related to this phenomenon and (2), presents the case study of the collapse of the argaric society, located in southeastern Spain. We carried out an exercise of correspondence between the aspects highlighted in the case study and the features postulated in the literature about the concept of collapse.

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    Potential energy savings and economic impact of residential buildings under national and regional efficiency scenarios: a Catalan case study  Open access

     Garrido Soriano, Nuria; Rosas Casals, Marti; Ivancic, Aleksandar; Alvarez Del Castillo, M. Dolores
    Energy and buildings
    Date of publication: 2012-06-01
    Journal article

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    Energy consumption in buildings accounts for a significant percentage of total world energy utilization. Great efforts have been made in order to reduce fossil energy consumption and mitigate its depletion by means of energy efficiency directives. The national transposition of such directives generates regional regulations that might be counterproductive if it is not clear which one is more restrictive. The main goal of this paper is to evaluate the potential of energetic savings of the dwellings in Catalonia and its economic impact, according to different scenarios of efficiency that have been defined according to current regulations at state and autonomic level. To achieve this objective, thirteen typologies of dwellings have been defined in order to categorize the stock of buildings in Catalonia. Simulations with LIDER software have been carried out in order to obtain the heating and cooling demand for each typology of dwelling in different climatic zones and orientations. The economic impact of each scenario has been stated as well. We show that the best normative scenario is not the regional but the national one, and only when full limitations imposed by the state regulations are fulfilled. Following the latter 6.4% reduction in CO2 emissions would be achieved, whereas following the former gives us only 2.8% reduction for year 2015. These results have been obtained considering a base case scenario without any energetic measures implemented for the same time line

    Postprint (final draft post-refereeing)

  • Període 10/2005 - 09/2010

     Rosas Casals, Marti
    Award or recognition

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  • Modeling climate change effects on winter ski tourism in Andorra

     Pons Pons, Marc; Johnson, Peter A.; Rosas Casals, Marti; Sureda Carbonell, Bàrbara; Jover Comas, Eric
    Climate research
    Date of publication: 2012-10-11
    Journal article

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    Energies renovables  Open access

     Rosas Casals, Marti; Martinez Magaña, Juan
    Date of publication: 2011
    Book chapter

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    Estalvi i eficiència energètica  Open access

     Rosas Casals, Marti; Martinez Magaña, Juan
    Date of publication: 2011
    Book chapter

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    Energia. Generalitats  Open access

     Rosas Casals, Marti; Martinez Magaña, Juan
    Date of publication: 2011
    Book chapter

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    Modification of the Perrine-Baum diagram to improve the calculation of high voltage electric lines  Open access

     Horta Bernus, Ricard; Rosas Casals, Marti
    Date: 2011-10-31
    Report

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    Through the history of Electrical Engineering education, vectorial and phasorial diagrams have been used as a fundamental learning tool. At present, computational power has replaced them by long data lists, the result of solving equation systems by means of numerical methods. In this sense, diagrams have been shifted to an academic background and although theoretically explained, they are not used in a practical way within specific examples. This fact may be against the understanding of the complex behavior of the electrical power systems by students. This article proposes a modification of the classical Perrine-Baum diagram construction to allowing both a more practical representation and a better understanding of the behavior of a high-voltage electric line under different levels of load. This modification allows, at the same time, the forecast of the obsolescence of this behavior and line’s loading capacity. Complementary, we evaluate the impact of this tool in the learning process showing comparative undergraduate results during three academic years

  • Influència del canvi climàtic en el turisme de neu del Pirineu

     Garola Crespo, Alvaro; Rosas Casals, Marti
    Participation in a competitive project

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    Analysis of major failures in Europe¿s power grid  Open access

     Rosas Casals, Marti; Solé, Ricard
    International journal of electrical power and energy systems
    Date of publication: 2011-03
    Journal article

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    Power grids are prone to failure. Time series of reliability measures such as total power loss or energy not supplied can give significant account of the underlying dynamical behavior of these systems, specially when the resulting probability distributions present remarkable features such as an algebraic tail, usually considered the footprint of self-organization and the existence of critical points. In this paper, 7 years (from 2002 to 2008) of Europe’s transport of electricity network failure events have been analyzed and the best fit for this empirical data probability distribution is presented. With the actual span of available data and although there exists a moderate support for the power-law model, the relatively small amount of events contained in the function’s tail suggests that causal factors other than self-organization or a critical state might be significantly ruling these systems’ dynamics.

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  • Power grids as complex networks: topology and fragility

     Rosas Casals, Marti
    Complexity in Engineering
    Presentation's date: 2010-02-22
    Presentation of work at congresses

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    We almost certainly agree that the harnessing of electricity can be considered the most important technological advance of the twentieth century. The development that allows this control is the power grid, an intricate system composed of generators, substations and transformers connected by cable lines hundreds of kilometers long. Its presence is nowadays so intertwined with ours, and so much taken for granted, that we are only capable of sensing its absence, disguised as a cascading failure or a blackout in its extreme form. Since these extreme phenomena seem to have increased in recent years and new actors, like highly liberalized markets or environmental and social constraints, are taking a leading role, different paths other than traditional engineering ones have been explored. In the last ten years, and mainly due to increasing computational capability and accessibility to data, the conceptual frame of complex networks has allowed different approaches in order to understand the usual (and not-so-usual) outcomes of this system. This paper considers power grids as complex networks. It presents some recent results that correlate their topology with their fragility, together with major malfunctions analysis, and for the European transmission power grid in particular.

    This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder

  • Discerning electricity consumption patterns from urban allometric scaling

     Horta Bernus, Ricard; Rosas Casals, Marti; Valverde Castillo, Sergi
    Complexity in Engineering
    Presentation's date: 2010-02-22
    Presentation of work at congresses

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    Assessing European power grid reliability by means of topological measures  Open access

     Rosas Casals, Marti; Corominas Murtra, Bernat
    WIT transactions on ecology and the environment
    Date of publication: 2009
    Journal article

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    Reliability assessment is crucial when dealing with complex systems, especially complex networks. Be they natural or man made, networks are able to sustain their functioning by means of a reliable set of components. The many functions a network can sustain are direct consequence of the topological structure that constraints and, at the same time, defines, the dynamical relation between its components. Therefore, some kind of relation between structure and dynamics should be expected to appear. In this paper, some of these relations that have been found for the European power grid are presented. Evidences for a critical relation between topology and dynamics are summarized, using some basic topological measures widely used in the developing complex networks paradigm. Finally, strategies for optimal management and operation of such networks are suggested.

    Publicat originalment a: WIT transactions on ecology and the environment, 2009, vol. 121, p. 527-537

  • Topological complexity of the electricity transmissión network. Implications in the sustainability Paradigm  Open access

     Rosas Casals, Marti
    Defense's date: 2009-12-18
    UNESCO Sustainability Chair, Universitat Politècnica de Catalunya
    Theses

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    Aquesta tesi explora i estudia l'estructura, dinàmica i evolució de la xarxa de transmissió d'electricitat des de la perspectiva dels sistemes complexos, essent el seu principal objectiu la definició de nous criteris i eines per ajudar a un disseny més eficient i sostenible de la xarxa de transmissió de potència. Per assolir aquest objectiu, s'han estudiat i analitzat dos conjunts de dades. D'una banda, la xarxa corresponent a la Unió per la Coordinació de Transport d'Electricitat (UCTE), que associa a la majoria dels operadors de xarxes elèctriques nacionals de l'Europa continental amb la finalitat de coordinar la producció i la demanda anual d'uns 2.300 TWh d'energia per 450 milions de clients de 24 països diferents. D'altra banda, l'evolució històrica de la xarxa de transport del Gestionaire du Réseau du Transport d'Electricité (RTE), responsable de l'explotació, manteniment i desenvolupament de la xarxa nacional mésgran d'Europa, la xarxa francesa de transport d'electricitat.Els resultats obtinguts fins al moment mostren diferències estadísticament significatives en l'estructura de les xarxes elèctriques, definint clarament comportaments dinàmics particulars que ens permeten segregar les xarxes europees en dos grups, a saber, fràgil i robust. Les xarxes fràgils es caracteritzen per les topologies més estructurades, mallades i no a l'atzar, mentre que les topològiques de caràcter més robust, contraintuïtivament, tenen estructures molts més aleatòries. Les conseqüències d'aquestes troballes per a la sostenibilitat de les xarxes d'infraestructures són importants en termes de cost i avaluació d'impactes i riscos. Es presenta així mateix un model per a l'evolució temporal i espacial d'una xarxa elèctrica. En aquest sentit, suggerim que la fragilitat topològica global augmenta quan es consideren accions de connectivitat de caire local a fi d'augmentar la fiabilitat de la xarxa a escala regional.Aquests resultats suggereixen la necessitat d'aplicar nous mètodes de disseny de la xarxa elèctrica així com noves eines amb capacitat per incloure aquests nous aspectes topològics en l'avaluació de l'eficiència i la fiabilitat de lamateixa.

    This Thesis explores the structure, dynamics and evolution of the electricity transmission network from a complexsystems perspective, its main objective being the definition of new criteria and tools to help to design a more efficientand sustainable transmission power grid. In doing so, two data sets have been explored and analyzed. On one hand,the Union for the Coordination of Transport of Electricity (UCTE) network, which associates most of the continentalEurope national power grid operators in order to coordinate the production and demand of some annual 2300 TWh ofenergy and 450 million customers from 24 countries. On the other hand, the Gestionaire du Réseau du Transportd'Electricité (RTE) transport network historical evolution, responsible for operating, maintaining and developing thebiggest national network in Europe, the French electricity transmission network.The results obtained so far show statistically significant dissimilarities in the structure of the power grids, clearlydefining and enclosing particular dynamic behaviors that enable us to segregate European networks in two sets,namely fragile and robust. Fragile networks are characterized by meshed topologies and non random structures whilerobust ones share more randomly generated topologies. The consequences of these finding for the sustainability ofinfrastructure networks are significant in terms of cost and risk assessment. A model for the evolution of a power gridnetwork is also presented. We suggest that global topological fragility increases when local connectivity schemes areadapted in order to increase local reliability.These outcomes appeal for new power grid design methods and tools capable to include these new topologicalaspects into efficiency and reliability assessments

  • Assessing power grid reliability by means of topological measures

     Rosas Casals, Marti
    Energy and Sustainability II
    Presentation's date: 2009-06-24
    Presentation of work at congresses

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    Energía y sostenibilidad: 5 años de experiencia del master en energía para la sostenibilidad  Open access

     Garcia Almiñana, Daniel; Garrido Soriano, Nuria; Horta Bernus, Ricard; Martinez Magaña, Juan; Molins Duran, Gemma; Rosas Casals, Marti; Rocuts Pabon, Asthriesslav; Ibáñez, Manel; Miranda, René; Rodríguez, Ramona; Báez, Julián; Lugo, Lisa; Silvero, Juan Carlos
    Congrés UPC Sostenible 2015
    Presentation's date: 2009-07-09
    Presentation of work at congresses

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    La presente comunicación pretende mostrar la experiencia adquirida tras cinco años de vigencia del “Master en Energía para la Sostenibilidad”. Inicialmente fue en modalidad presencial en Terrassa y desde el 2007, fruto de trabajos desarrollados en el Proyecto Europeo URB-AL R4-B6-04 "Energías renovables y redes de desarrollo local”, en modalidad semipresencial en el Campus de Terrassa de la Universitat Politècnica de Catalunya, así como en las sedes de Estelí en Nicaragua (Universidad Nacional Autónoma de Nicaragua) y Asunción en Paraguay (Universidad Católica Nuestra Señora de la Asunción y Universidad Nacional de Asunción).

  • Assessing power grid reliability by means of topological measures

     Rosas Casals, Marti
    Energy and Sustainability II
    Presentation of work at congresses

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    Robustness of the European power grids under intentional attack  Open access

     Solé, Ricard V.; Rosas Casals, Marti; Corominas, B; Valverde, S
    Physical review E: statistical, nonlinear, and soft matter physics
    Date of publication: 2008-02
    Journal article

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    The power grid defines one of the most important technological networks of our times and sustains our complex society. It has evolved for more than a century into an extremely huge and seemingly robust and well understood system. But it becomes extremely fragile as well, when unexpected, usually minimal, failures turn into unknown dynamical behaviours leading, for example, to sudden and massive blackouts. Here we explore the fragility of the European power grid under the effect of selective node removal. A mean field analysis of fragility against attacks is presented together with the observed patterns. Deviations from the theoretical conditions for network percolation (and fragmentation) under attacks are analysed and correlated with non topological reliability measures.

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    Topological vulnerability of the European power grid under errors and attacks  Open access

     Rosas-Casals, M; Rosas Casals, Marti; Valverde, S; Solé, Ricard V.
    International journal of bifurcation and chaos
    Date of publication: 2007-07
    Journal article

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    We present an analysis of the topological structure and static tolerance to errors and attacks of the September 2003 actualization of the Union for the Coordination of Transport of Electricity (UCTE) power grid, involving thirty-three different networks. Though every power grid studied has exponential degree distribution and most of them lack typical small-world topology, they display patterns of reaction to node loss similar to those observed in scale-free networks. We have found that the node removal behaviour can be logarithmically related to the power grid size. This logarithmic behaviour would suggest that, though size favours fragility, growth can reduce it. We conclude that, with the ever-growing demand for power and reliability, actual planning strategies to increase transmission systems would have to take into account this relative increase in vulnerability with size, in order facilitate and improve the power grid design and functioning

    Electronic version of an article published as "International journal of bifurcation and chaos", vol. 17, no. 7, July 2007, p. 2465-2475. DOI No: 10.1142/S0218127407018531. © Copyright World Scientific Publishing Company

    Postprint (author’s final draft)

  • Master en energía para el desarrollo sostenible. Módulo 8: Ahorro, Eficiencia y Gestión de la Energía

     Rosas Casals, Marti; Bestraten Castells, Sandra Cinta; Hormias Laperal, Emilio; Manyes Castellà, Anna; Garrido Soriano, Nuria; Steinbauer Pan, Rudolfo; Vargas Cabral, Enrique A.; González, Vicente A.; Martinez Magaña, Juan; Garcia Almiñana, Daniel; Perez Guindal, Elsa; Gamboa, Gonzalo
    Date of publication: 2007
    Book

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  • La complexitat de les xarxes tecnològiques

     Rosas Casals, Marti
    I International Conference on Sustainability Measurement and Modelling
    Presentation's date: 2006-11-16
    Presentation of work at congresses

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  • Memòria 2003 de la Càtedra UNESCO en Tecnología, desenvolupament Sostenible, desequilibris i Canvi Global

     Carrera Gallissa, Enric; (Redactors), Enric Carrera I Anna Andrés; Cendra Garreta, Jaume; Escribano Rodriguez de Robles, Beatriz; Rosas Casals, Marti; Bárbara, Sureda
    Memòria Càtedra UNESCO a la UPC en tecnologia, desenvolupament sostenible, desequilibris i canvi global
    Date of publication: 2004-05
    Journal article

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  • Instalaciones de calefacción

     Rosas Casals, Marti
    Date of publication: 2003-11
    Book

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  • Energia solar tèrmica

     Cendra Garreta, Jaume; Rosas Casals, Marti
    Date of publication: 2001-02
    Book

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  • Eficiència Energètica al Vapor Universitari

     Rosas Casals, Marti; Cendra Garreta, Jaume; Horta Bernus, Ricard; Martinez Magaña, Juan; Montaña Puig, Juan
    Date of publication: 2001-02
    Book

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  • TOMO IV Eficiencia Energética al Vapor Universitari: Climatización, cogeneración, trigeneración y energía solar fototérmica

     Martinez Magaña, Juan; Cendra Garreta, Jaume; Horta Bernus, Ricard; Montaña Puig, Juan; Rosas Casals, Marti
    Date of publication: 2000-01
    Book

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