2,958 research outputs found

    3D Multi-Subband Ensemble Monte Carlo Simulator of FinFETs and nanowire transistors

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    In this paper we present the development of a 3D Multi Subband Ensemble Monte Carlo (3DMSB-EMC) tool targeting the simulation of nanoscaled FinFETs and nanowire transistors. In order to deliver computational efficiency, we have developed a self-consistent framework that couples a MSB- EMC transport engine for a 1D electron gas with a 3DPoisson- 2DSchro ̈dinger solver. Here we use a FinFET with a physical channel length of 15nm as an example to demonstrate the appli- cability and highlight the benefits of the simulation framework. A comparison of the 3DMSB-EMC with Non-Equilibrium Green’s Functions (NEGFs) in the ballistic limit is used to verify and validate our approach

    The development of air traffic in Sicily

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    The aim of this work is to analyse the air traffic development that interested the airport system in Sicily, consisting of the airport of Palermo “Falcone –Borsellino”, the airport of Catania “Fontanarossa” and that one of Trapani-Birgi “Vincenzo Florio”. The analysis of the possible growth of air traffic volume and performance in Sicily was mainly suggested by the growing importance of the Mediterranean region like a new crossroad of the worldwide traffic on the East-West line. It gives a new chance for the development of this area that mustn’t be loosed. Globalization and the migrant flows from South and East towards the Western Europe, makes of the southern Italy a strategic knot for passengers and goods movements. So, new investments and infrastructures improvements that will be realized in this area are a value added not only for the southern Italy but also for the whole country. We have examined the potential demand attraction for passengers and goods movements in the Sicilian airports considered. For a more careful evaluation of the changes occurred into Sicilian air transport system, the research aimed to: § determine their "catchment area" through the evaluation of accessibility (isochrones); § analyse the air traffic data and the existing degree of integration, not only between the airports and the area, but also in terms of demand in the short and in the long period. Finally, we have evaluated the possibility of integration of traffic flows management among the two airports of Palermo and Trapani, in order to analyse if this two airports are complementary rather than competitors.

    La riqualificazione della viabilitĂ  costiera per la mobilitĂ  dolce: il caso di Palermo

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    The attractiveness and the availability of services offered in urban areas nearby the port terminals are conditioned by the improvement of the connection of different urban transport systems and by the enhancement of the accessibility. But they should be based on the overall improvement of urban mobility. The structural organization of the territory is favored by the presence of links, which realize an infrastructure system to the different levels of connection and accessibility. The interventions could include the requalification of the coastal strip, including the road network component. Attention should be given to the supply quality, the rationalization of a linear model based on the coastal viability and on the access to the poles of the city and its hinterland. It should be also took in to account a rationalization of urban traffic, using exchange parking areas with enhanced public transport systems, and of the creation of pedestrian and bicycle paths for soft mobility on the short and medium range distances

    IL RUOLO DELLA QUALITÀ PERCEPITA DEI PERCORSI PEDONALI NELLA SCELTA DEL TRASPORTO PUBBLICO

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    Il fenomeno del pendolarismo oggigiorno coinvolge ampie fasce della popolazione, manifestandosi attraverso spostamenti sistematici, spesso quotidiani, dal proprio luogo di residenza verso altra destinazione, per motivi di studio o di lavoro. La definizione di spostamento pendolare prescinde dalla distanza percorsa o dal tempo di viaggio. Tipicamente, i pendolari si spostano tra differenti aree di regioni metropolitane, seguendo percorsi multimodali, costituiti anche da itinerari di “mobilità dolce” (pedonale o ciclabile). La mancanza di una cultura della pianificazione urbanistica, la diffusione sul territorio delle funzioni residenziali e l’accentramento delle attività produttive e commerciali hanno determinato, negli ultimi decenni, una crescita intensa dei fenomeni di pendolarismo. A causa del notevole sviluppo dei centri urbani, divenuti delle vere e proprie “città diffuse”, la durata degli spostamenti pendolari ha subito forti incrementi, occupando, in molti casi, gran parte della vita dei viaggiatori. Il pendolarismo, inoltre, è considerato uno dei fattori che maggiormente contribuiscono all’inquinamento atmosferico, a causa della congestione della rete stradale metropolitana. Ne deriva un crescente degrado della “qualità” della vita per gli stessi pendolari e per gli individui residenti nelle aree limitrofe alle grandi arterie di collegamento. Per risolvere questi problemi, si è da tempo affermato l’orientamento ad elaborare politiche per la promozione dell’uso del trasporto collettivo, volte, in particolare, a conseguire miglioramenti dei servizi pubblici sia sul piano dell’efficienza sia su quello dell’efficacia. Tuttavia, in generale, l’attenzione è rivolta alla progettazione dell’offerta del singolo modo di trasporto pubblico, senza considerare l’integrazione con altre forme di trasporto collettivo e con le modalità di “mobilità dolce”. Ne discende una scarsa competitività dei servizi di trasporto pubblico, con la conseguenza di una ripartizione modale molto sbilanciata a favore dell’auto

    Infrastructure, Tariff and Legal Action: How to Achieve a Climate-Friendly Transport System

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    Transportation absorbs about 70% of oil consumption in EU countries. The fuels that burn in the field of transport are composed of 96% of oil. Energy efficiency of road and air traffic must also be improved. But transport environmental impacts reductions should be made necessarily through a transfer of traffic from the car, lorries and aircraft to train, ship, and non motorized two-wheelers into the EU cities. In fact the former are large producers of greenhouse gases, while the latter are more environmentally friendly means of transport in climate. Reaching an annual increase of 1% of the modal split in favour of more sustainable means of transport on the environment must be set as a goal ecologic. Legal, infrastructure and tariff measures have to be proposed, in addition to technical measures (reduction of traffic, growth in the energy efficiency of vehicles, reduction of ravelled distances, improved logistics, etc.). Legal measures refer to possible law limits in terms on fuel consumption and CO2 emissions due to traffic set by the EU. Infrastructure measures can be distinguished on the basis of the concerned territory. On the one hand there is the city, where it seems appropriate to move with intermodal chain, more secure and environmentally friendly. On the other hand there are fundamentally the suburbs, where investment in new transport infrastructures may be contradictory in terms of climate protection. Tariff measures express the already established concept of "who produces pollution, he pays". The external costs generated by different modes of transport have to be progressively turned over to users

    3D Multi-Subband Ensemble Monte Carlo Simulator of FinFETs and nanowire transistors

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    In this paper we present the development of a 3D Multi Subband Ensemble Monte Carlo (3DMSB-EMC) tool targeting the simulation of nanoscaled FinFETs and nanowire transistors. In order to deliver computational efficiency, we have developed a self-consistent framework that couples a MSB- EMC transport engine for a 1D electron gas with a 3DPoisson- 2DSchro ̈dinger solver. Here we use a FinFET with a physical channel length of 15nm as an example to demonstrate the appli- cability and highlight the benefits of the simulation framework. A comparison of the 3DMSB-EMC with Non-Equilibrium Green’s Functions (NEGFs) in the ballistic limit is used to verify and validate our approach

    A demand-based methodology for planning the bus network of a small or medium town

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    This work aims at developing a demand-based methodology for designing the bus network of a small or medium town. The proposed modelling tool adopts a multi-agent objective function which evaluates performance in the context of different stakeholders: the surplus of travellers (car and bus users); the bus service provider’s revenues and operation costs. This approach was applied to an existing bus network, serving Trapani, which is a medium town in the south of Italy (Sicily), with 100000 inhabitants. The busbased public transport system attracts only about 5% of commuter trips within Trapani (source: National Institute of Statistics, 2005). This paper reports on an analysis of the application of the proposed multiagent modelling tool to two planning scenarios: the first is short-term and characterized by a budget constraint (slight changes in the availability of drivers and vehicles) and the second long-term with new investments in new buses to improve services and increase patronage. In both cases, the impact of the recent car park charging policy launched by the local administration was considered. The decision variables for the optimisation procedure were route, service frequency and capacity of each bus line. A random utility model was employed to forecast the mode choices for trips within Trapani and the travel demand-supply equilibrium was obtained using the DUE (deterministic user equilibrium) assignment algorithm, for private transport, and the hyperpath network loading algorithm, for public transport. The optimisation procedure led to a more efficient bus network characterized by increase in bus frequencies and a better performance in terms of reduced travel time, especially for trips bound for the “old town” in the morning. In addition, a higher number of origin-destination pairs were served, at the expense of the need to interchange between the inner more frequent and the outer less frequent services. This implied that the number of transfers from one bus line to another significantly increased
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