744 research outputs found

    A physically-based approach for evaluating the hydraulic invariance in urban transformations

    Get PDF
    Transformation of urban areas satisfies hydraulic invariance (HI) if the maximum flow rate outgoing the area stays unchanged. The HI can be respected by dimensioning appropriate water storage volumes or low impact developments (LID) to balance the soil sealing and ground levelling effects. In order to comply with HI, some Italian regional legislation and river basin authority provide for the creation of storage tanks whose volume must be estimated through simple conceptual rainfallrunoff models. In this work a physically based approach for evaluating HI is proposed. It is based on interpolating the results from a large number of hydraulic simulations conducted using FullSWOF, which is an open source code developed by the University of Orl茅ans. In this software the shallow water equations are solved using a finite volume scheme and friction laws and infiltration models are included. Simulations have been carried out considering the effect of three properties of the area, that is: the saturated hydraulic conductivity of soil, the slope of ground surface and the standard deviation of ground elevation around the mean level. Using the results, interpolating laws for the peak discharge and the critical rainfall duration as function of the three basin parameters have been derived. A parametric hydrograph as a function of the basin parameters and rainfall duration is defined and a HI evaluation method based on routing the parametric hydrograph is proposed. The results from this approach have been compared with those from non-physically based methods currently used, such as the direct rainfall approach and the linear reservoir approach. The comparison shows that the difference between these conceptual methods with that one proposed here is strongly dependent on the runoff coefficient value. It is also not possible to predict whether they are conservative or not

    Electronic equalization for advanced modulation formats in dispersion-limited systems

    Get PDF
    We investigate in this letter the use of electronic equalization on dispersion limited systems for different modulation formats. Besides analyzing equalization on standard NRZ intensity modulation as a reference, we focus on two advanced modulation formats, Duobinary and Differential Phase Shift Keying (DPSK) which are recently gaining large attention. We demonstrate that the introduction of an electronic equalizer strongly improves standard NRZ performance, whereas it has a limited effect on Duobinary and DPSK formats. Moreover, we give rules for the optimal choice of the equalizer transversal filter parameters, i.e., the number of taps and the delay between taps

    Identidades acad茅micas y gesti贸n de equipos: 驴misi贸n imposible?

    Get PDF
    [EN] This article is a reflection on the possible relationships between academic identities and team management. Rather than negating the relative importance of management, it is argued that only by adopting practices that are mindful of academic identities can one attempt to arrive at a novel notion of the idea of the university that is the result of a real dialogic co-construction among different parties (academics, managers, administrators, leaders, students etc) which is underpinned by a set of shared meanings and intentions.[ES] El art铆culo presenta una reflexi贸n sobre las posibles relaciones entre las identidades acad茅micas y la gesti贸n de equipo. M谩s que negar la importancia relativa de la gesti贸n, se argumenta que s贸lo adoptando pr谩cticas que tengan en cuenta las identidades acad茅micas ser谩 posible llegar a una noci贸n novedosa de la universidad como resultado de una construcci贸n dial贸gica real entre las distintas partes, (acad茅micos, directivos, administradores, l铆deres, estudiantes, etc.) que est茅 apuntalada por un conjunto de significados e intenciones compartidas.聽Di Napoli, R. (2009). Academic identities and team management: mission impossible?. REDU. Revista de Docencia Universitaria. 7(4):1-13. https://doi.org/10.4995/redu.2009.6227OJS11374Aubert, N. (2003). La culture de l'urgence: la soci茅t茅 malade du temps. Paris: Flammarion.Aubert, N. and De Gaulejac, V. (1991/2007). Le co没t de l'excellence. Paris: Seuil.Bamber, V. et Al. (eds) (2009). Enhancing Learning, Teaching, Assessment and Curriculum in Higher Education. Maidenhead: SRHE and Open University Press.Bauman, Z. (2000). Liquid Modernity. London: Polity Press.Benasayag, M. and Del Rey, A. (2008). Elogio del conflitto. Milano: Feltrinelli.Barnett, R. and Di Napoli, R. (2008). Changing Identities in Higher Education: Voicing Perspectives. London: Routledge.Block, P. (2008). Community: The Structure of Belonging. San Francisco: Berrett-Koelher Publishers.Castoriadis, C. (1975/1999). L' institution imaginaire de la soci茅t茅. Paris: Seuil.Chiddick, D. 'Short term goals will damage our long-term health and strength'. Times Higher Education, No, 1,909, 13-19 August 2009 (pp24-25).Coffield, F. and Williamson, B. (eds). Repositioning Higher Education. Buckingham: SRHE and Open University Press.Dall'Alba, G. and Barnacle, R. 'An ontological turn for higher education'. Studies in Higher Education, Volume 32, Issue 6, December 2007 (pp679 - 691).De Gaulejac, V. (2005/2009). La soci茅t茅 malade de la gestion: id茅ologie gestionnaire, pouvoir managerial et harc猫lement social. Paris: Editions du Seuil.Di Napoli, R. (2003). Modern Languages: Which Identities? Which Selves? Institute of Education, University of London (unpublished doctoral thesis).Evans, C. (1988). Language People: The Experience of Teaching and Learning Modern Languages in British Universities. Buckingham: SRHE and Open University Press.Evans, C. (1993). English People: The Experience of Teaching and Learning English in British Universities. Buckingham: SRHE and Open University Press.Gibbons, M. et Al (1994) (eds). The New Production of Knowledge: The Dynamics of Science and Research in Contemporary Societies. London: Sage.Habermas, J. (2007). La condizione intersoggettiva. Bari: Laterza.Henkel, M. (2000). Academic Identities and Policy Change in Higher Education. London: Jessica Kingsley Publishers.Knights, D. and McCabe, D. (2003). Organization and Innovation: Guru Schemes and American Dreams. Maidenhead: Open University Press.Magatti, M. (2009). Libert脿 immaginaria: le illusioni del capitalismo tecnico-nichilista. Milano: Feltrinelli.Martin, E. (1999). Changing Academic Work: Developing the Learning University. Buckingham: SRHE and Open University Press.Mintzberg, H. 'Rebuilding Companies as Communities'. Harvard Business Review, Volume 87, Number 7/8, July-August 2009 (pp140-143).Nixon, J. (2008). Towards the Virtuous University: The Moral Bases of Academic Practice. London: Routledge.Nye Jr, J. S. (2008). The Power to Lead. Oxford: Oxford University Press.Ortega y Gasset (1930/2007). Misi贸n de la Universidad. Madrid: Alianza Editorial.Readings, B. (1997). The University in Ruins. Cambridge, Massachusetts: Harvard University Press.Rowland, S. (2006). The Enquiring University: Compliance and Contestation in Higher Education. Maidenhead: SRHE and Open University Press.Sandel, M. J. (2007). The Case against Perfection: Ethics and the Age of Genetic Engineering. Cambridge, Massachusetts: The Beknapp Press of Harvard University Press.Senge, P. M. (1990/2006). The Fifth Discipline: The Art & Practice of the Learning Organisation. London: Random House.'What do you want in the new Warden?'. Staff Hallmark, Goldsmiths College, University of London, Issue 174, July 2009 (p5).Strathern, M. (2000) (ed). Audit Cultures: Anthropological Studies in Accountability, Ethics and the Academy. London: Routledge.Taylor, C. (1992). Sources of the Self: The Making of the Modern Identity. Cambridge: CUP.Taylor, P.G. (1999). Making Sense of Academic Life: Universities and Change. Buckingham: SRHE and Open University Press.Virilio, P. (2009). Le futurisme de l'instant: stop-eject. Paris: Editions Galil茅e

    El desarrollo Educativo, una mirada externa: rasgos nacionales y aspectos institucionales en el caso del Imperial College London

    Get PDF
    [EN] The aim of this article is both to inform and reflect on the state and status of educational development in the UK, with special reference to the English case, using Imperial College London as an example of current trends and issues. While describing current trends in educational development, the paper attempts to reflect critically on a number of current issues: the need for an institutional strategy for educational development; the relationship between generic and discipline-based development; the 'service' status often ascribed to centres of educational development and its implications; and the need for securing a safe career paths for developers. At times of change in the Spanish context, the Spanish reader should find some of such themes familiar and it may be of interest to him/her to gauge the level of the debate on them in the UK.[ES] El prop贸sito central del presente art铆culo es informar y reflexionar acerca del estado y del estatus del desarrollo educativo en la Educaci贸n Superior en el Reino Unido, especialmente en el caso de Inglaterra, tomando el caso de la Universidad Imperial College of London como ejemplo de los temas y de los rasgos de lo que actualmente preocupa en esta tem谩tica. A la vez que describe los rasgos b谩sicos del proceso de desarrollo educativo, el texto trata de refle jar de un modo cr铆tico diferentes aspectos implicados en 茅l: la necesidad de estrategias institucionales para el mismo; el dilema entre un desarrollo basado en disciplinas o bien en un enfoque transversal de la docencia, el estatus de 鈥渟ervicio鈥, com煤nmente atribuido a los centros de desarrollo educativo y sus implicaciones; as铆 como la necesidad de asegurar una carrera profesional para los encargados de promover y dar apoyo al desarrollo mencionado. En los tiempos de cambio que se dan en el contexto espa帽ol, el lector encontrar谩 algunos temas que pueden serle familiares y quiz谩s podr谩 juzgar el nivel de debate que se da en el ReinoUnido acerca de los mismos.Di Napoli, R. (2007). Educational development - a view from outside: national trends and institutional issues at Imperial College London. REDU. Revista de Docencia Universitaria. 5(1):1-13. https://doi.org/10.4995/redu.2007.6291OJS11351DfES web last accessed 8 November 2005: http://www.dfes.gov.uk/HEA web last accessed 8 November 2005: http://www.heacademy.ac.uk/HEFCE web last accessed 8 November 2005: http://www.hefce.ac.uk/HEFCE et al (October 2005) Higher Education in the United Kingdom, 2005/10; HEFCE, London Imperial College London (2005) Statistics Pocket Guide 2004-5; Imperial College LondonImperial College London web last accessed 8 November 2005: http://www.imperial.ac.uk/NCIHE (National Committee of Inquiry into Higher Education) (1997) Higher Education in the Learning Society ('Dearing Report'); NCIHE, LondonTimes Higher Education Supplement (2005) World University Rankings; the Times Higher Education Supplement, LondonQAA web last accessed 8 November 2005: http://www.qaa.ac.uk/Barnett, R. (1997). Higher Education: A Critical Business. Buckingham: SRHE and Open University Press.Land, R. (2004). Educational Development: Discourse, Identity and Practice. Buckingham: SRHE and Open University Press.L酶vlie, L., Mortensen, P.K. and S. E. Nordenbo (eds) (2003). Educating Humanity: Bildung in Postmodernity. Oxford: Blackwell.Trowler, P. (1998). Academics Responding to Change: New Higher Education Frameworks and Academic Cultures. Buckingham: SRHE and Open University Press

    Challenges for a transition towards the smart grids

    Get PDF
    The recent evolution of the power and energy systems has been driven by a number of factors concerning network modernisation, energy efficiency improvements, growing attention to the environmental and social impact, higher diffusion of renewable energy generation, as well as guaranteeing system security and enabling new services and consumer participation. This paper presents an overview on the key challenges for the future energy systems, that will have to face with the energy trilemma including environmental and social sustainability, energy security and energy equity. The impact of the use of electricity in the energy systems is growing, calling for the assessment of future scenarios to understand the possibility of occurrence of critical conditions. The technical analyses can be supported by the definition of appropriate indicators, some of which are recalled in this paper. Emergent issues like transportation system electrification and system resilience have to be addressed in a holistic way. The various aspects of energy transition and energy integration require more interdisciplinary analyses merging competences from the technical, economic, and sociological fields

    RISK ASSESSMENT OF MALICIOUS ATTACKS AGAINST POWER SYSTEMS

    Get PDF
    The new scenarios of malicious attack prompt for their deeper consideration and mainly when critical systems are at stake. In this framework, infrastructural systems, including power systems, represent a possible target due to the huge impact they can have on society. Malicious attacks are different in their nature from other more traditional cause of threats to power system, since they embed a strategic interaction between the attacker and the defender (characteristics that cannot be found in natural events or systemic failures). This difference has not been systematically analyzed by the existent literature. In this respect, new approaches and tools are needed. This paper presents a mixed-strategy game-theory model able to capture the strategic interactions between malicious agents that may be willing to attack power systems and the system operators, with its related bodies, that are in charge of defending them. At the game equilibrium, the different strategies of the two players, in terms of attacking/protecting the critical elements of the systems, can be obtained. The information about the attack probability to various elements can be used to assess the risk associated with each of them, and the efficiency of defense resource allocation is evidenced in terms of the corresponding risk. Reference defense plans related to the online defense action and the defense action with a time delay can be obtained according to their respective various time constraints. Moreover, risk sensitivity to the defense/attack-resource variation is also analyzed. The model is applied to a standard IEEE RTS-96 test system for illustrative purpose and, on the basis of that system, some peculiar aspects of the malicious attacks are pointed ou

    Analiza svojstava izmjenjiva膷kih mre啪nih priklju膷aka fotonaponskih sustava

    Get PDF
    The present trend towards extended adoption of energy production from renewable sources is leading to increased attention towards the diffusion of grid-connected photovoltaic (PV) systems. Different technologies are available for the connection of the PV systems to the grid through inverter-based Power Conditioning Units (PCUs). This paper presents the results of a comparative study referred to the characteristics of different types of PCUs, based on the experimental results obtained for a wide range of solar irradiance and operating conditions. The performance of the grid connection has been characterised by using a set of parameters, referred both to the DC and to the AC side of the inverter, such as the efficiency of the maximum power point tracking, the DC/AC efficiency, the power factor and the harmonic distortion of voltage and current at the interface with the grid. The PV systems have been further characterised by considering their ability of avoiding the undesired islanding operation through relatively fast detection of the islanding conditions and fast PV system shutdown. The results are discussed and compared to the specifications provided by the manufacturers and to the limits imposed by some standards.Sada拧nji trend koji vodi prema sve ve膰oj potrebi za proizvodnjom energije iz obnovljivih izvora energije usmjerava pove膰anu pozornost prema primjeni fotonaponskih (PV) sustava spojenih u mre啪u. Razli膷ite su tehnologije raspolo啪ive za spajanje PV sustava na mre啪u preko izmjenjiva膷kih energetskih jedinica (PCU). Ovaj rad prikazuje rezultate usporednog prou膷avanja karakteristika razli膷itih tipova izmjenjiva膷kih energetskih jedinica (PCU) na osnovi eksperimentalnih rezultata dobivenih za 拧iroki opseg Sun膷eva zra膷enja i uvjeta rada. Svojstva mre啪nog spoja okarakterizirana su kori拧tenjem skupa parametara koji se odnose i na istosmjernu (DC) i na izmjeni膷nu (AC) stranu izmjenjiva膷a, kao 拧to su efikasnost pra膰enja to膷ke maksimalne snage, DC/AC efikasnosti, faktor snage i harmoni膷ko izobli膷enje napona i struja na spoju s mre啪om. Fotonaponski sustavi su dalje okarakterizirani uzimaju膰i u obzir njihove sposobnosti izbjegavanja ne啪eljene operacije oto膷noga rada njegovom relativno brzom detekcijom i isklju膷ivanjem. Provedena je rasprava o rezultatima, a zatim su rezultati uspore膽eni sa specifikacijama dobivenim od proizvo膽a膷a i s ograni膷enjima proisteklima iz nekih standarda

    Analiza svojstava izmjenjiva膷kih mre啪nih priklju膷aka fotonaponskih sustava

    Get PDF
    The present trend towards extended adoption of energy production from renewable sources is leading to increased attention towards the diffusion of grid-connected photovoltaic (PV) systems. Different technologies are available for the connection of the PV systems to the grid through inverter-based Power Conditioning Units (PCUs). This paper presents the results of a comparative study referred to the characteristics of different types of PCUs, based on the experimental results obtained for a wide range of solar irradiance and operating conditions. The performance of the grid connection has been characterised by using a set of parameters, referred both to the DC and to the AC side of the inverter, such as the efficiency of the maximum power point tracking, the DC/AC efficiency, the power factor and the harmonic distortion of voltage and current at the interface with the grid. The PV systems have been further characterised by considering their ability of avoiding the undesired islanding operation through relatively fast detection of the islanding conditions and fast PV system shutdown. The results are discussed and compared to the specifications provided by the manufacturers and to the limits imposed by some standards.Sada拧nji trend koji vodi prema sve ve膰oj potrebi za proizvodnjom energije iz obnovljivih izvora energije usmjerava pove膰anu pozornost prema primjeni fotonaponskih (PV) sustava spojenih u mre啪u. Razli膷ite su tehnologije raspolo啪ive za spajanje PV sustava na mre啪u preko izmjenjiva膷kih energetskih jedinica (PCU). Ovaj rad prikazuje rezultate usporednog prou膷avanja karakteristika razli膷itih tipova izmjenjiva膷kih energetskih jedinica (PCU) na osnovi eksperimentalnih rezultata dobivenih za 拧iroki opseg Sun膷eva zra膷enja i uvjeta rada. Svojstva mre啪nog spoja okarakterizirana su kori拧tenjem skupa parametara koji se odnose i na istosmjernu (DC) i na izmjeni膷nu (AC) stranu izmjenjiva膷a, kao 拧to su efikasnost pra膰enja to膷ke maksimalne snage, DC/AC efikasnosti, faktor snage i harmoni膷ko izobli膷enje napona i struja na spoju s mre啪om. Fotonaponski sustavi su dalje okarakterizirani uzimaju膰i u obzir njihove sposobnosti izbjegavanja ne啪eljene operacije oto膷noga rada njegovom relativno brzom detekcijom i isklju膷ivanjem. Provedena je rasprava o rezultatima, a zatim su rezultati uspore膽eni sa specifikacijama dobivenim od proizvo膽a膷a i s ograni膷enjima proisteklima iz nekih standarda

    Special issue: The doctoral journey: Perspectives

    Get PDF

    Full Scale Reinforced Concrete Beam-Column Joints Strengthened with Steel Reinforced Polymer Systems

    Get PDF
    This paper presents the results of an experimental campaign performed at the Laboratory of Materials and Structural Testing of the University of Salerno (Italy) in order to investigate the seismic performance of reinforced concrete (RC) beam-column joints strengthened with steel reinforced polymer (SRP) systems. With the aim to represent typical fa莽ade frames' beam-column subassemblies found in existing RC buildings, specimens were provided with two short beam stubs orthogonal to the main beam and were designed with inadequate seismic details. Five members were strengthened by using two different SRP layouts while the remaining ones were used as benchmarks. Once damaged, two specimens were also repaired, retrofitted with SRP, and subjected to cyclic test again. The results of cyclic tests performed on SRP strengthened joints are examined through a comparison with the outcomes of the previous experimental program including companion specimens not provided with transverse beam stubs and strengthened by carbon fiber-reinforced polymer (CFRP) systems. In particular, both qualitative and quantitative considerations about the influence of the confining effect provided by the secondary beams on the joint response, the suitability of all the adopted strengthening solutions (SRP/CFRP systems), the performances and the failure modes experienced in the several cases studied are provided
    corecore