A feasible algorithm for typing in Elementary Affine Logic

We give a new type inference algorithm for typing lambda-terms in Elementary Affine Logic (EAL), which is motivated by applications to complexity and optimal reduction. Following previous references on this topic, the variant of EAL type system we consider (denoted EAL*) is a variant without sharing and without polymorphism. Our algorithm improves over the ones already known in that it offers a better complexity bound: if a simple type derivation for the term t is given our algorithm performs EAL* type inference in polynomial time.Comment: 20 page

Marginal Activity Access Cost (MAAC): a new indicator for sustainable Land Use/Transport (LUT) planning

The paper presents the ‘Marginal Activity Access Cost’, an accessibility indicator providing estimation in monetary terms of the impacts on mobility and on the environment of locating a single new activity in a specific zone of the urban area. In the first part of this paper, the new indicator is presented and compared to other accessibility indicators proposed in literature. In the second part, the MAAC is validated through an application to the urban area of Rome. The paper concludes with brief remarks on using the proposed accessibility indicator as index of performance for sustainable spatial planning

Changing accessibility, dwelling price and the spatial distribution of socio-economic activities

In this paper we present an activities location choice model with endogenous price which simulate, based on Expected Random Utility principle, the behavior of several agents of the urban system (i.e. the workers distinguished by income, the firms by economic sector) to estimate the spatial distribution of socioeconomic activities within the study area as well as the impact of differentiated changing accessibility on the dwellings price. The study area for this research is the metropolitan area of Napoli (South-Italy), for which we show the results of the model estimation and the results of a “backcasting” application to future transportation scenarios

Competition on fast track: an analysis of the first competitive market for HSR services

This paper gives an overview of the dual effects of the opening, in Italy, of the new HSR line with a single operator (between 2005-2012) and the effects of a new operator entering the HSR market (2012-onward), on supply, demand and prices, thus inferring the effects of competition in this typically monopolistic market. The analyses are based on source data (laws and regulations, business plans, timetables, prices) as well as ad hoc extensive surveys, such as on-board counts on the HSR and intercity trains, retrospect surveys, and RP/SP interviews. In addition, an integrated modeling system has been developed to forecast the effects of competing titnetables/services/prices in terms of different HSR operators, competing modes (air/auto/railways), services (1st class/2nd class, etc.) and newly generated trips

An elastic demand schedule-based multimodal assignment model for the simulation of high speed rail (HSR) systems

HSR represents the future of medium-haul intercity transport. In fact, a number of HSR projects are being developed all over the world despite the financial and economic crisis. Such large investments require reliable demand forecasting models to develop solid business plans aiming at optimizing the fares structure and the timetables (operational level) and, on the other hand, at exploring opportunities for new businesses in the long period (strategic level). In this paper we present a model system developed to forecast the national passenger demand for different macroeconomic, transport supply, and HSR market scenarios. The core of the model is based on the simulation of the competition between transportation modes (i.e. air, auto, rail), railways services (intercity vs. High Speed Rail) and HSR operators using an explicit representation of the timetables of all competing modes\services (schedule-based assignment). This requires, in turn, a diachronic network representation of the transport supply for scheduled services and a nested logit model of mode, service, operator, and run choice. To authors’ knowledge this represents the first case of elastic demand, schedule-based assignment model at national scale to forecast HSR demand. The overall modeling framework has been calibrated based on extensive traffic counts and mixed RP-SP interviews gathered between 2009 and 2011, on the Italian multimodal transportation system. The results of the models estimation are presented, and, some applications to test HSR service options (i.e. fares and timetable) of a new operator entering the HSR market and competing with the national incumbent are discussed

Estimating and visualizing perceived accessibility to transportation and urban facilities

In this paper we present some estimated functions of residential location utility, perceived by individuals, varying with the distance from selected transportation and urban facilities, such as metro and train stations, highway and road junctions, as well as hospitals, green spaces and leisure centres. By summing up such functions we get a measure of the overall convenience of residing in different zones of a given study area, that we call “perceived accessibility”. The functions, estimated by means of SP-surveys, have been implemented into an accessibility Interactive Visualisation Tool (i.e. InViTo) and applied to case study of Rome (Italy). The application allows to validating the use of interactive visualization tools to measure accessibility and its potential usability to produce easy-to-read accessibility maps of urban scenarios of urban development