Polarità commerciali in Lombardia: tendenze evolutive e geografie a supporto della governance territoriale

Il settore della distribuzione commerciale in Italia è segnato negli ultimi anni da una serie di trasformazioni che hanno influenzato l’assetto del mercato nazionale. Il sistema d’offerta risultante non è omogeneamente distribuito nel territorio e uno degli elementi caratterizzanti è la presenza di “polarità commerciali” che si differenziano per dinamismo, attrattività e rilevanza degli impatti a scala sovralocale. L’obiettivo di questo contributo è quello di evidenziare l’insieme degli “effetti territoriali” delle Grandi Strutture di Vendita (GSV) con un approfondimento particolare per le “polarità commerciali pianificate”, usando come caso di studio il contesto regionale della Lombardia anche attraverso gli esiti di alcune recenti esperienze di ricerca curate dal Laboratorio Urb&Com del Politecnico di Milano, Dipartimento di Architettura e Studi Urbani. Per farlo sono stati elaborati dati complessi relativi alle polarità pianificate e alla loro competizione per il presidio del mercato lombardo, identificando le pratiche insediative ricorrenti di queste strutture e i processi di adattamento al conteste regionale di strategie globali sviluppate dagli operatori. Questo approfondimento si è dimostrato un fertile campo di esplorazione, che ha permesso (a.) di definire una metodologia originale di studio delle Grandi Strutture di Vendita e, al contempo, (b.) di elaborare un quadro originale ed aggiornato della situazione lombarda, contributo di conoscenza utile a supportare le future politiche regionali sul tema e le programmazioni settoriali ad esso collegate (attività economiche, mobilità, lavoro, territorio, ecc.).Over the last two decades, the retail sector in Italy suffered a set of transformations that changed the national market. The resulting retail network is not homogeneously distributed over the national space and the presence of a variety of "retail polarities" – different in dynamism, appeal to users and spatial impacts – marks the offer. This contribution is aimed at focusing the impacts of the Grandi Strutture di Vendita (GSV), a typology of retail structures defined by Italian law that gathers together shopping malls, retail parks and large specialty stores. These are intended as "planned retail polarities" because developers need local and regional authorizations in their settlement process. Using the Lombardy Region as a case study and presenting the outcomes of a recent research developed by Urb&Com Lab research team, we propose a reading of several global trends, a new map of these structures and a critical interpretation of these information. Results of this exploration allowed us (a.) to define an original methodology to study GSVs and, at the same time, (b.) to provide an original and updated map of regional situation. This map could contribute to future regional policies on this topic and, more in general, to integrate the current sectoral view on retail to a wider regional agenda (that involve economy, mobility, labor market, sustainability, etc.)

A three-phase model for surge distribution studies in electrical machines

This paper describes a computer model for surge distribution studies in the winding of electrical machines. The computer model takes the coil as the basis for the analysis and uses multiconductor transmission line theory to obtain the transference matrix for the winding. Several practical formulations based on machine design characteristics are used for calculating electrical parameters. Flux penetration into the iron core and mutual coupling between coils in different phase windings are incorporated into the analysis. The model was validated by a comparison of predicted and calculated results in a high voltage motor. © 1996 IEEE

Modeling distance algorithms to acquire autoreclose settings

Power demand is currently growing in Mexico at an annual rate above 5 %. The actual transmission system has to increase its power transfer capacity without compromising the power supply and the system integrity. Power protection engineers are thus resorting more to single pole tripping schemes with automatic re-closings. Relay coordination tasks are thus becoming increasingly complex. This article presents a methodology by which, through time domain computer simulations, one can establish proper relay settings for such a highly demanding scenario. © 2007 IEEE

The Gould's belt very large array survey. III. the orion region

This paper describes a new transmission line model for electromagnetic transient analysis in time domain which accounts for non-uniform and frequency dependence effects. This model is based on the Radulet approach to line equations and on finite differences in characteristic coordinates. The model is validated by comparisons with study cases reported in the specialized literature, as well as with the EMTP/ATP and the numerical laplace transform. " 2005 Elsevier Ltd. All rights reserved.",,,,,,"10.1016/j.ijepes.2005.09.006",,,"http://hdl.handle.net/20.500.12104/45106","http://www.scopus.com/inward/record.url?eid=2-s2.0-32644452269&partnerID=40&md5=c57bd91e107f7ee47c9c0be961ca8ab7",,,,,,"3",,"International Journal of Electrical Power and Energy Systems",,"15

Comparison of transmission tower models for evaluating lightning performance

This paper focuses on the representation of tall metallic structures, such as power line towers, by means of vertical transmission line segments. Some of the most common tower models are tested here. The differences between the single vertical line models and the vertical multi-conductor ones are demonstrated through the comparison with a field experiment. � 2003 IEEE

The effects of non-uniformities and frequency dependence of line parameters on electromagnetic surge propagation

This paper describes a new transmission line model for electromagnetic transient analysis in time domain which accounts for non-uniform and frequency dependence effects. This model is based on the Radulet approach to line equations and on finite differences in characteristic coordinates. The model is validated by comparisons with study cases reported in the specialized literature, as well as with the EMTP/ATP and the numerical laplace transform. © 2005 Elsevier Ltd. All rights reserved

The state and security in Mexico: Transformation and crisis in regional perspective

A switch model previously proposed in references [1], [2| and [3] for power electronics applications is adopted here to simulate electromagnetic transients in power systems. The switch model is in the generic form for EMTP analysis, consisting of a constant conductance element and a current source in parallel. Switch operations are simulated by means of the current source only; therefore, at these operations, the conductance matrix representing the power system under study is maintained constant throughout an entire simulation. It is shown in this paper that the switch model is very general, it is efficient and numerically very stable. " 2003 IEEE.",,,,,,"10.1109/PTC.2003.1304646",,,"http://hdl.handle.net/20.500.12104/45307","http://www.scopus.com/inward/record.url?eid=2-s2.0-84861512083&partnerID=40&md5=e8489bac47849997a943a1b2725dc2c4",,,,,,,,"2003 IEEE Bologna PowerTech - Conference Proceedings",,"78

The transient simulation of a power network with invariant admittance matrix

A switch model previously proposed in references [1], [2| and [3] for power electronics applications is adopted here to simulate electromagnetic transients in power systems. The switch model is in the generic form for EMTP analysis, consisting of a constant conductance element and a current source in parallel. Switch operations are simulated by means of the current source only; therefore, at these operations, the conductance matrix representing the power system under study is maintained constant throughout an entire simulation. It is shown in this paper that the switch model is very general, it is efficient and numerically very stable. © 2003 IEEE