1,720,980 research outputs found
ODME
No full textIl software ODME è una routine aggiuntiva per il software TRANSCAD della Caliper, che applica una nuova procedura per la stima delle matrici Origine-Destinazione (matrici O-D), in grado di integrare informazioni provenienti da più fonti, di origine diversa (diverse matrici O-D campionarie; dati censuari; modelli di generazione, attrazione e distribuzione della domanda; conteggi di traffico), tenendo conto della loro affidabilità secondo l’approccio bayesiano e consentendo un’operazione integrata di validazione dei modelli.
La principale motivazione dello sviluppo di questo software deriva dal fatto che gli algoritmi di stima O-D mediante conteggi di traffico disponibili in commercio utilizzano come informazione aggiuntiva una sola matrice O-D, allo stesso livello di disaggregazione di quella voluta, e procedono ricercando la matrice O-D che, assegnata alla rete, meglio riproduce i conteggi di traffico, indipendentemente dallo scostamento rispetto alla matrice iniziale. Ciò implica il rischio che la procedura produca una sensibile distorsione della matrice iniziale; inoltre, non consente di considerare simultaneamente l’eventuale presenza di altre fonti di informazione
SINTAC - Software di Sincronizzazione del Traffico per l'ATAC
No full textIl software SINTAC applica diversi metodi di regolazione del traffico (massima banda, minimo ritardo) ed integra diverse procedure euristiche per la regolazione delle arterie sincronizzate, tenendo conto anche della presenza di trattamento preferenziale degli autobus. Il modello di traffico utilizzato tiene conto sia della variabilità temporale della domanda, con conseguente possibilità di temporanea sovra-saturazione, sia del possibile effetto di spill-back delle code sulla capacità dei nodi a monte
A Time-Dependent Electric Vehicle Routing Problem with Recharging Stations
No full textThe rapid proliferation of electric vehicles (EVs) has emerged as a vital solution to reduce greenhouse gas
emissions and our reliance on fossil fuels. However, the limited driving range of EVs, along with the
sparse distribution of recharging stations, poses significant challenges for fleet operators and
transportation planners. In this context, the Time-Dependent Electric Vehicle Routing Problem with
Recharging Stations (TDEVRP-RS) serves as an indispensable optimization model, designed to
streamline the operational efficiency of electric vehicle fleets while minimizing operational costs and
ensuring optimal energy utilization. The TDEVRP-RS model comprehensively considers various factors,
such as time-dependent travel times, recharging station availability, energy consumption, and driving
range restrictions. This dynamic approach not only enables efficient route planning but also promotes the
incorporation of renewable energy sources, encouraging a sustainable transportation ecosystem. In
addition, floating car data is employed to estimate the travel speed for each link on an hourly basis
throughout the operational day. As a result, this paper introduces a comprehensive mathematical
formulation, which is implemented in the General Algebraic Modeling System (GAMS) to enable
solution through exact methods and ensure subsequent validation. A variety of efficient metaheuristic
algorithms are proposed to tackle the presented mathematical model in real-sized scenarios. In the end,
the road network of Rome is utilized to visualize vehicle routes, offering a precise and high-quality
depiction of the generated tours
A quasi-dynamic traffic assignment model for large congested urban road networ
No full textThe paper deals with simulation of congested urban areas through dynamic traffic assignment models and presents a new quasidynamic traffic assignment model that improves realism and effectiveness of both usual static traffic assignment models and other quasi-dynamic models recently introduced in the literature. The new model has been applied to a real large-scale road network (the town of Rome) and has been validated through a comparison with a very large set of floating car data. Results of validation reveal that the quasi-dynamic traffic assignment model provided a rather satisfactory goodness of fit, which is comparable with that reported in literature as a result of application of a much more sophisticated simulation and calibration procedure, applied to a road network having similar characteristics of size and congestion degree
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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