1,721,067 research outputs found
Comparison of headway-based public transport models
No full textIn this paper we evaluate the output from four headway-based public transport model variants for modeling the public transports in Stockholm, Sweden. The results from the four models are analyzed and compared to trip observations. The comparisons are based on model instances where the parameters in the generalized travel time function are calibrated. The best possible parameter values have been found using the calibration procedures SPSA and Compass search. Two different objective functions have been evaluated for the calibration.
Numerical experiments have been performed using a public transport model implemented in Visum by Storstockholms lokaltrafik. For the calibration and analysis, trip observations from the Swedish national travel survey and data generated from a public transport trip planner are used.
From the numerical results, it is concluded that it is of less importance to find the best possible parameter values in the generalized cost function than selecting the best model variant. For the Stockholm public transport model, the numerical results indicate that the models in the class of Random departure time models result in a better fit to the observed trips than the models in the class of Optimal strategies
Generating Traveller Location Data from a Microsimulation Model
No full textTato práce obsahuje přístup do činění výzkum v oblasti mobilních datových připojení pro použití v dopravní modelování, přičemž takové údaje nejsou zatím k dispozici. To popisuje přípravu syntetických Detail Volací záznamy (CDR) z drah vozidel s mikroskopickou simulační studie. Zkoumá, do jaké míry je možné pozorovat měnící se dopravní podmínky a volby trasy z těchto záznamů. Simulace zahrnuje dálniční úsek a obytné silnicích v Solna, Stockholm a provádí se pomocí softwaru AIMSUN. Data poptávka je odvozen ze senzorů pevných podél dálnice úseku. Python skript pro pokročilé programovací rozhraní AIMSUN (API) se používá k extrakci trajektorie vozidla z běžící simulace. Mobilní připojení a modely volání generace přeložit trajektorie na CDR. Několik datových sad, které se liší v podkladové poptávky po dopravě a seskupení považovány silničních úseků jsou generovány. Datové soubory jsou analyzovány z hlediska celkového zatížení systému, průměrná velikost buňky, průměrná doba setrvání buňka a opakované připojení sekvencí. Navíc, dva způsoby, jak extrahovat poptávky v původ-cílových dvojic z údajů jsou porovnány. První uznává cestovní pokyny z pozice odebíraných buněk a druhá využívá spojení sekvencí. Bylo zjištěno, že je možné zvolit cestování účastníků z dat pomocí filtrování je na velkých buněk a vzorů spojení. Algoritmy musí být vyškoleni, aby uznaly tyto specifické regionální modely, které se skládají z buněk sekvencí. na zatížení v těchto buňkách základě měnící se požadavky v síti jsou identifikovány. Na základě analýzy doby buňka setrvání účastníků, vyplývající zácpy v simulované síti je rozpoznán rychle. Usuzuje se, že volba trasy je možné efektivně identifikovat pomocí vzorů připojení.This thesis contains an approach to do research on mobile connectivity data for the use in traffic modeling, while such data is not available yet. It describes the generation of synthetic Call detail records (CDR) from the vehicle trajectories of a microscopic simulation study. It investigates in how far it is possible to observe changing traffic conditions and route choices from these records. The simulation includes a highway stretch and residential roads in Solna, Stockholm and is carried out using the software Aimsun. The demand data is derived from sensors fixed along the highway stretch. A python script for the Aimsun advanced programming interface (API) is used to extract the vehicle trajectories from a running simulation. Mobile connectivity and call generation models translate the trajectories to CDR. Several data sets that differ in the underlying traffic demand and the grouping of regarded road stretches are generated. The data sets are analyzed in terms of total system load, average cell size, average cell dwell time and repeated connection sequences. Additionally, two ways to extract demand in origin-destination pairs from the data are compared. The first recognizes travel directions from the position of the subscribed cells and the second utilizes connection sequences. It is observed that it is possible to select traveling subscribers from the data by filtering them for large cells and connection patterns. Algorithms need to be trained to recognize those specific regional patterns that consist of cell sequences. Based on the load in these cells, changing demands in the network are identified. By analyzing the cell dwell time of subscribers, arising congestion in the simulated network is recognized quickly. It is concluded that route choices can effectively be identified by using connection patterns
Taxation shift in road traffic
No full textDenna rapport sammanfattar del 1 av projektet "Skatteväxling i trafiken", som har genomförts vid Linköpings universitet på uppdrag av Trafikverket. Sammanfattning på svenska.Skatteväxling i vägtrafiken – systemutformning och införandestrateg
Taxation shift in road traffic
No full textDenna rapport sammanfattar del 1 av projektet "Skatteväxling i trafiken", som har genomförts vid Linköpings universitet på uppdrag av Trafikverket. Sammanfattning på svenska.Skatteväxling i vägtrafiken – systemutformning och införandestrateg
Why modeling of heavy goods vehicles matters when designing congestion pricing schemes
No full textDifferentiated tolls for cars and heavy goods vehicles (HGVs) may improve the efficiency of congestion pricing schemes. Not only do private trips by car and commercial activities by HGV differ in how the time is valued by the user/operator, in general, one additional truck will also contribute to the congestion more than one additional car. In this paper we show how different modeling approaches for HGV route choice and demand may affect the evaluation of road pricing schemes. Also, we provide a small example to illustrate potential problems, and present results for a larger model of the German city Stuttgart.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
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