1,720,962 research outputs found
Hardware-in-the-Loop and Traffic-in-the-Loop for Testing Cooperative Intersection Management
No full textA simulation is a useful tool for evaluating the impacts of various changes in a transportation system, especially in the case of real-time traffic-adaptive control systems, which must undergo extensive laboratory testing before being implemented in a field environment. Various simulation environments are available, from software-only to hardware-in-the-loop simulations, each of which plays a specific role in implementing a traffic control system. This study applied a CA-MPC (Model Predictive Control based on a Cellular Automata model) for a real-time traffic-adaptive control framework as it progressed from a laboratory project to actual field implementation. The traditional software-only simulation environment and extensions to a hardware-in-the-loop simulation are presented, describing the migration of CA-MPC onto the traffic controller hardware itself. In addition, a new enhancement to the standard software-only simulation is described, which allows remote access such that the simulation and traffic control scheme are not required to reside locally
A hybrid traffic flow model for traffic management with human-driven and connected vehicles
Get PDFThis paper proposes a hybrid traffic flow model able to support the implementation of traffic management strategies in the presence of human-driven and connected vehicles. The model is based on the combination of two models: an aggregate model (the cell transmission model) and a disaggregate model (the cellular automata model). The model was tested considering three main layouts, namely a ring-shaped arc, a signalised link, and a grid network with four origins and four destinations, and then calibrated on real data. The model was also applied in the presence of connected vehicles. Our results point out the model’s local consistency in terms of wave propagation and its suitability with respect to the benchmark models as well as in the presence of connected vehicles
A Study on Users' Behaviour Towards Electric Vehicles in Immature Markets: The Argentina Case Study
No full textThe paper aims to investigate the different attributes that may influence the choosing decision on the purchase of an electric vehicle. In particular, the research focuses on the analysis of an “immature” market such the case of the Argentinean market context. From the methodological point of view, the main purpose relies on the survey data collection and data analysis and modelling. Furthermore, the results achieved from a specific Stated Preferences survey carried out on a sample of Argentinian university students are shown. Therefore, the research aims to quantify and discuss the main determinants of the choice phenomenon through the specification and calibration of a choice model based on the Random Utility Theory
Key Factors Influencing the Decision to Buy an Electric Vehicle in Emerging Markets: A Comparison Between University Students’ Behavior in Italy and Argentina
No full textThe transition from Internal Combustion Engine Vehicles (ICEVs) to electric vehicles (EVs) is a tricky issue, but particularly challenging in those markets that are characterized by high ICEVS ownership rates and that may be identified as emerging markets due to the small diffusion of the technology and of the related infrastructures. This study delves into modeling the willingness to buy an EV by young adults within the emerging Italian market, and to draw a comparison with the findings of a previous study carried out on the Argentinian market. To this aim a stated preferences survey was carried out at the University of Salerno (Italy), and then compared with the same survey designed and carried out at the University of Cordoba (Argentina). The Random Utility Paradigm was employed to model the preferences of the respondents, by focusing on the influence of instrumental attributes and psycho-attitudinal factors through a Mixed Binomial Logit formulation and Hybrid Choice model with Latent variables, respectively. The findings suggest that attitudes and perceptions play a substantial and similar role in emerging markets, with only slight differences across the two markets
CALIBRATION AND VALIDATION OF A MACROSCOPIC TRAFFIC FLOW MODEL BASED ON PLATOON DISPERSION AND QUEUE PROPAGATION
Get PDFThis paper proposes a preliminary calibration and validation of a macroscopic traffic flow model for signalised junctions. In fact, on the network signal setting design problem, a reliable modelling approach must be adopted to acknowledge the traffic flow effects, considering two phenomena: queue dispersion and spillback. The proposed model is an extension of the space-time discrete Cell Transmission Model (CTM), which can simulate dispersion and horizontal queue. This preliminary calibration and validation use real-world data collected on an arterial of the city of Salerno (south of Italy). Results showed that the estimated parameters are consistent with the literature
Parameters Estimation of a Microscopic Traffic Flow Sub-Model Within a Multiscale Approach Using Experimental Data
No full textFuture traffic contexts will likely involve the coexistence of human-driven vehicles and connected and automated vehicles (CAVs). To assess the impact of CAVs, especially in large-scale applications, intermediate hybrid multi-scale models can be used. These models are easily adaptable to traffic control strategies by employing disaggregated modelling in regions where such strategies are implemented and macroscopic modelling in other regions indirectly affected by the controlled infrastructure. This paper focuses on a model previously established in the literature, the H -CA&CTM (Hybrid Cellular Automata -CA-Cell Transmission Model-CTM), with an emphasis on the micro model that can be implemented in the hybrid traffic flow model. The research has two primary aims: 1) Investigate the calibration of the CA model with respect to various cell lengths using two distinct approaches: simulating all vehicles together in a closed ring layout and simulating each vehicle using data obtained from its respective follower; 2) Utilize vehicle trajectory data for the calibration procedure, enabling a comprehensive comparison of methods. Two detailed approaches were considered:1. Measured Leader – Simulated Follower interaction approach.2. Simulated Leader – Simulated Follower interaction approach. The major finding of the paper is that the calibrated parameters obtained using the Simulated Leader approach display greater regularity across different cell lengths
Innovative traffic flow modelling tools for advanced urban traffic control
Get PDF2019 - 2020The current evolution of vehicles with the development of new on-board technologies, allow for increasingly more connected vehicles, which also enables the development of more intelligent and autonomous vehicles. The result of including connected and autonomous vehicles on the network has the potential to achieve several benefits, as better values of traffic flow and reduce congested areas or congestion in general, a more sustainable mobility from a more efficient driving behaviour, safer trips, increase accessibility to transport services, exchange of information for a better traffic prediction, etc.
The use of these technologies does not guarantee reliable and accurate results unless they are enabled by specific models behind them. To do so, it is necessary to study the vehicular flow in the presence of CAVs. This arises two challenges:
• a methodological challenge, to have a vehicular flow model that allows us to implement this new technology in a mixed context of connected and unconnected vehicles.
• an operational challenge, in which by combining the data collected from the connected vehicles and the traffic flow model, it is possible to adopt an advanced control strategy, and therefore achieve the benefits of having CAVs in the network in an urban context.
The objectives of this thesis are:
• Obtain an urban network management through the combination of a network traffic control strategy and link metering, optimising green times, offsets and stage sequences on an on-line network control and link control (Chapter 4.1)
• Develop “energy-saving” control strategies considering EVs energy consumption patterns, to support the development of a unified network traffic control strategies aiming at minimising also EVs energy consumption (Chapter 4.2).
• Integrate a traffic control strategy with the Single-Segment Green Light Optimal Speed Advisory (S-GLOSA), optimizing the speed of connected and autonomous vehicles (Chapter 4.3).
• Develop a traffic flow model capable of simulating a mixed context of connected and unconnected vehicles, combining a macroscopic model along the arc and then a microscopic model at the nodes, concentrating there all the computational and analytical efforts, with a reduced number of parameters to calibrate (Chapter 5.1 and 5.2)
• Integrate such model with an advanced control strategy for the optimisation of traffic light plans, with the capability to work on real time, receiving data acquired through sensors, cameras, radar, probe vehicles, etc., to obtain a more accurate and reliable prediction (Chapter 5.2)
• Compare this traffic flow model with macroscopic and microscopic benchmark models (Chapter 5.3)
The dissertation focuses on the developed hybrid traffic flow model (H – CTMCA), obtained by combining a macroscopic approach to model links with a microscopic approach to model nodes. To this end, two traffic flow models were adopted: a simplified microscopic Cellular Automata model (CA), and a macroscopic Cell Transmission Model (CTM). The proposed hybrid model proved suitable for analysing traffic flow phenomena and can also be adopted for traffic control in both cases: in the context of multi objective optimisation (for instance based on surrogate indicators) and with the presence of connected vehicles. [edited by Author]XXXIII cicl
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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