Vehicular Traffic on Networks: Comparison among Solutions Modeling Vertex Flow

2015 - 2016Nowadays, the analysis of issues associated with road traffic within urban and suburban areas has taken a leading role in trying to implement efficient plans of transport regulations by taking advantage of the available infrastructure. In fact, the occurrence frequency of slowdowns phenomena and strong congestions has greatly multiplied and caused a series of inconveniences and poor services for citizens such as the increased risk of accidents and air and noise pollution. In order to solve the problem of urban mobility, it is possible to act with a rational management of infrastructure and a road artery-planning program using simulators able to identify critical points in the design phase and evaluate the correctness of the proposed interventions. For this reason, it is important to use mathematical models to predict the evolution of the traffic starting from the knowledge of quantities such as cars’ densities at a given time instant. These models are classified into microscopic and macroscopic ones. The former analyze the behavior of each single vehicle, while the latter consider situations that arise from the interaction of many particles derived based on concepts of the fluid dynamics. The aim of the present research work is to review macroscopic fluid dynamic models dealing with traffic flow on road networks and to propose new solutions for the dynamics at intersections based on the integration of optimization criteria about the vehicular flow and rules for the distribution of traffic. In detail, the Thesis analyzes, describes and highlights the following topics and results: physical variables that regulate road traffic and the relation that links them with each other, and some fluid dynamic macroscopic models for traffic on a single road (i.e. LWR, Payne Whitham, Aw-Rascle, Zhang, Third order and Multilane models); vehicular traffic network based on the fluid dynamic model LWR and conservation laws, and characterized by some aspects to be solved like initial conditions on not infinite roads and dynamics at intersections. About the former aspect, the corresponding boundary value problems are presented and solved, while about the latter aspect the solution to Riemann Solver is given by considering also additional rules for traffic distribution that are well defined in new appropriate models simulating the presence of traffic lights at intersections with variable or fixed cycles of red-green; numerical schemes used for the discretization of the conservation law and the solution of the dynamic at intersections. In detail, Godunov scheme, used for the determination of density values for road sections in different time instants starting from the initial density value of each road on the analyzed road network, is considered; numerical results about an experimentation of some of the new models defined that are implemented within a road traffic simulator prototype by reproducing the behavior of vehicular densities on a road network with appropriate dynamics at intersections. These results are then compared in order to prove the correctness of each model, evaluate the performances and analyze some specific situations for optimization of car traffic. Considerations and results obtained in this research work by simulation of traffic flows may be useful as support for authorities responsible for urban road network in order to make an appropriate urban planning by evaluating the needs of the country. In fact, it could be possible to avoid traffic congestion at certain areas or time slots, bring down the rate of air pollution or noise and minimize risks due to overcrowding of vehicles on roads. [edited by author]Oggigiorno, l'analisi delle problematiche legate al traffico stradale nelle aree urbane e suburbane ha avuto un ruolo di primo piano nel tentativo di attuare piani efficienti di regolamentazione dei trasporti sfruttando le infrastrutture disponibili. Infatti, la frequenza dei fenomeni di rallentamento e di congestione si è moltiplicata e ha causato una serie di inconvenienti e scarsi servizi per i cittadini, come l'aumento del rischio di incidenti e di inquinamento atmosferico ed acustico. Al fine di risolvere il problema della mobilità urbana, è possibile agire con una gestione razionale delle infrastrutture e un programma di pianificazione dell'arteria stradale utilizzando simulatori in grado di individuare punti critici nella fase di progettazione e valutare la correttezza degli interventi proposti. Per questo motivo, è importante utilizzare modelli matematici per prevedere l'evoluzione del traffico a partire dalla conoscenza di quantità come la densità di un veicolo in un dato istante di tempo. Tali modelli sono classificati in microscopici e macroscopici. I primi analizzano il comportamento di ogni singolo veicolo, mentre i secondi considerano situazioni che derivano dall'interazione di molte particelle derivate in base ai concetti della fluido-dinamica. Lo scopo del presente lavoro di ricerca è quello di analizzare i modelli fluido-dinamici macroscopici che trattano il flusso di traffico sulle reti stradali e di proporre nuove soluzioni per le dinamiche agli incroci basate sull'integrazione di criteri di ottimizzazione del flusso veicolare con regole di distribuzione del traffico. In dettaglio, la tesi analizza, descrive ed evidenzia i seguenti argomenti e risultati: le variabili fisiche che regolano il traffico stradale e la relazione che le lega tra loro, ed alcuni modelli fluido-dinamici macroscopici per il traffico su singola strada (ovvero i modelli LWR, Payne-Whitham, Aw-Rascle, Zhang, Third order e Multilane); la rete di traffico veicolare basata sul modello fluido-dinamico LWR e sulle leggi di conservazione e caratterizzata da alcuni aspetti da risolvere come le condizioni iniziali sulle strade non infinite e le dinamiche agli incroci. Per quanto riguarda il primo aspetto, vengono presentati e risolti i problemi di “condizione al bordo” corrispondenti, mentre per quanto riguarda il secondo aspetto viene presentata la soluzione al problema di Riemann considerando anche regole aggiuntive e ben definite per la distribuzione del traffico in nuovi modelli che simulano la presenza di semafori agli incroci con cicli variabili o fissi di rosso-verde; gli schemi numerici per la discretizzazione della legge di conservazione e la soluzione alle dinamiche agli incroci. In dettaglio, viene considerate lo schema di Godunov, usato per determinare i valori di densità dei segmenti di strada in diversi istanti di tempo a partire dal valore di densità iniziale di ogni strada nella rete stradale analizzata; i risultati numerici della sperimentazione di alcuni dei nuovi modelli definiti, che sono implementati all’interno di un prototipo di simulatore del traffico stradale riproducendo il comportamento delle densità dei veicoli nella rete stradale con appropriate dinamiche agli incroci. Tali risultati sono successivamente confrontati per provare la correttezza di ogni modello, valutare le prestazioni e analizzare alcune specifiche situazioni per ottimizzare il traffico stradale. I risultati e le considerazioni emerse dal presente lavoro di ricerca simulando flussi veicolari possono essere di aiuto alle autorità responsabili della rete stradale urbana per progettare un efficiente piano di viabilità valutando le reali necessità della città. Infatti, si potrebbero evitare congestioni di traffico in certe aree della città o in specifici intervalli temporali, diminuire sostanzialmente il tasso di inquinamento atmosferico o acustico e minimizzarne i rischi dovuti al sovraffollamento di veicoli lungo le strade. [a cura dell'autore]XV n.s

Entropy solutions for a traffic model with phase transitions

In this paper, we consider the two phases macroscopic traffic model introduced in [P. Goatin, The Aw-Rascle vehicular traffic flow with phase transitions, Mathematical and Computer Modeling 44 (2006) 287-303]. We first apply the wave-front tracking method to prove existence and a priori bounds for weak solutions. Then, in the case the characteristic field corresponding to the free phase is linearly degenerate, we prove that the obtained weak solutions are in fact entropy solutions \`a la Kruzhkov. The case of solutions attaining values at the vacuum is considered. We also present an explicit numerical example to describe some qualitative features of the solutions

Prediction of low frequency sound fields in buildings near railway lines

The design of new buildings in the vicinity of railway lines must consider protection against noise and vibrations induced by railway traffic. However, the prediction methods available involve heavy numerical models which have frequency limitations. In this paper a prediction method combining finite elements (FEM) with natural mode analysis is presented for use in reinforced concrete buildings with heavy walls. The method considers 2D FEM models of the railway, ground and buildings to identify the transfer function of vibration from the railway to building foundations. Also 3D models of the buildings are considered to identify the transfer functions of vibration from foundations to walls and floors. Finally, as the impedance of heavy walls and floors is much higher than the acoustic impedance of air, the numerically assessed vibration fields of walls and floors are used to calculate sound fields in rooms by means of natural mode analysis. A set of in situ measurements were made in two different situations in order to calibrate the prediction method and also to identify the factors which most affect vibration and sound transmission

The blob and the block. When the rhetoric of the smooth and the striated went all wrong

This paper conforms to a view of architecture and the distribution of urban space as bio-political parameters of dominance and resistance. Using G. Deleuze & F. Guattari’s seminal essay on 1444. The Smooth and the Striated, I intend to show how Global Capitalism, by replicating the discourse of the smooth and the ungraspable, has voided Dialectics of its subversive potential.El presente artículo contempla la arquitectura y la distribución del espacio urbano como parámetros biopolíticos de dominación y resistencia. Valiéndose del ensayo 1444. Lo liso y lo estriado, de Gilles Deleuze & Felix Guattari, se pretende demostrar cómo el capitalismo global, gracias a su capacidad para emular el discurso de lo fluido y lo intangible, habrá conseguido despojar a lo dialéctico de su potencial subversivo

Delay-Tolerant Stochastic Algorithms for Parking Space Assignment

This paper introduces and illustrates some novel stochastic policies that assign parking spaces to cars looking for an available parking space. We analyze in detail both the main features of a single park, i.e., how a car could conveniently decide whether to try its luck at that parking lot or try elsewhere, and the case when more parking lots are available, and how to choose the best one. We discuss the practical requirements of the proposed strategies in terms of infrastructure technology and vehicles’ equipment and the mathematical properties of the proposed algorithms in terms of robustness against delays, stability, and reliability. Preliminary results obtained from simulations are also provided to illustrate the feasibility and the potential of our stochastic assignment policies

New Perspectives on Modelling and Control for Next Generation Intelligent Transport Systems

This PhD thesis contains 3 major application areas all within an Intelligent Transportation System context. The first problem we discuss considers models that make beneficial use of the large amounts of data generated in the context of traffic systems. We use a Markov chain model to do this, where important data can be taken into account in an aggregate form. The Markovian model is simple and allows for fast computation, even on low end computers, while at the same time allowing meaningful insight into a variety of traffic system related issues. This allows us to both model and enable the control of aggregate, macroscopic features of traffic networks. We then discuss three application areas for this model: the modelling of congestion, emissions, and the dissipation of energy in electric vehicles. The second problem we discuss is the control of pollution emissions in eets of hybrid vehicles. We consider parallel hybrids that have two power units, an internal combustion engine and an electric motor. We propose a scheme in which we can in uence the mix of the two engines in each car based on simple broadcast signals from a central infrastructure. The infrastructure monitors pollution levels and can thus make the vehicles react to its changes. This leads to a context aware system that can be used to avoid pollution peaks, yet does not restrict drivers unnecessarily. In this context we also discuss technical constraints that have to be taken into account in the design of traffic control algorithms that are of a microscopic nature, i.e. they affect the operation of individual vehicles. We also investigate ideas on decentralised trading of emissions. The goal here is to allocate the rights to pollute fairly among the eet's vehicles. Lastly we discuss the usage of decentralised stochastic assignment strategies in traffic applications. Systems are considered in which reservation schemes can not reliably be provided or enforced and there is a signifficant delay between decisions and their effect. In particular, our approach facilitates taking into account the feedback induced into traffic systems by providing forecasts to large groups of users. This feedback can invalidate the predictions if not modelled carefully. At the same time our proposed strategies are simple rules that are easy to follow, easy to accept, and significantly improve the performance of the systems under study. We apply this approach to three application areas, the assignment of electric vehicles to charging stations, the assignment of vehicles to parking facilities, and the assignment of customers to bike sharing stations. All discussed approaches are analysed using mathematical tools and validated through extensive simulations

Diccionario interactivo ilustrado técnico bilingüe : herramientas, materiales y elementos para la construcción y afines

Diccionario producto de la colaboración de instructores de los programas de construcción, automatismos, refrigeración, motores y carpintería del Centro de Operación y Mantenimiento Minero del SENA, en el que se recopila alfabéticamente en idioma inglés y de forma visual los materiales y equipos utilizados comúnmente en construcción así como su definición y su traducción al español.Dictionary product of the collaboration of instructors of the programs of construction, automatisms, refrigeration, motors and carpentry of the Center of Operation and Mining Maintenance of the SENA, in which the materials and equipment commonly used in English are collected alphabetically in English language construction as well as its definition and its translation into Spanish.Aa-Bb--Cc-Dd--Ee-Ff--Gg-Hh--Ii-Jj--Kk-Ll--Mm-Nn--Oo-Pp--Qq-Rr--10.Ss-Tt-- Uu-Vv--Ww--Contrucction Program--Automation Program--Refrigeration Program--Automotive ProgramnaTítulo en portada “Diccionario interactivo técnico ilustrado bilingüe; materiales, herramientas y elementos para la construcción y afines”204 página

Avaliação da influência de árvores na dispersão de poluentes atmosféricos em street canyons utilizando fluidodinâmica computacional (CFD)

Orientadora: Profa. Dra. Mônica Beatriz KolicheskiCoorientador: Prof. Dr. Fernando Pablo DevecchiDissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Meio Ambiente Urbano e Industrial em parceria com o Serviço Nacional de Aprendizagem Nacional (SENAI) e a Universität Stuttgart da Alemanha. Defesa : Curitiba, 14/04/2023Inclui referênciasResumo: Dados de 2019 revelam que mais de 90% da população mundial vive em áreas com níveis de poluição do ar acima dos limites estabelecidos pela Organização Mundial da Saúde (OMS). A atividade humana, especialmente em áreas urbanas com alta concentração de indústrias e tráfego de veículos, tem sido a principal causa da degradação da qualidade do ar e contribui para as mudanças climáticas. O conhecimento da dispersão de poluentes do ar em grandes centros urbanos é importante para mudar o cenário atual e melhorar o bem-estar e a saúde da população. Dessa forma, neste estudo, foi desenvolvido um modelo de dispersão de dois tipos de poluentes do ar: dióxido de carbono (CO2) e material particulado fino (MP2,5) em um street canyon hipotético. Os conceitos de fluidodinâmica computacional (CFD) e as ferramentas do software Open Source Field Operation and Manipulation (OpenFOAM) foram empregados para realizar simulações considerando diferentes cenários, que incluíram a presença ou ausência de árvores. O objetivo foi investigar o impacto da arborização na ventilação natural, dispersão e influência nas concentrações de CO2 e MP2,5. O comportamento dos poluentes foi modelado usando as equações de Navier-Stokes com médias de Reynolds (RANS) e com o modelo de turbulência k-?. Para a geração da geometria e domínio computacional, utilizou-se o software Salome, enquanto o OpenFOAM foi empregado para gerar a malha e executar os cálculos das equações matemáticas. Os resultados das simulações foram visualizados com o software ParaView e demonstraram que os efeitos aerodinâmicos são mais significativos em cenários com velocidade inicial do vento de 1 m/s e direção paralela ao eixo principal da rua. Além disso, a presença de árvores mostrou-se relevante na redução das concentrações dos poluentes avaliados. Essas descobertas destacam a importância da arborização e de estratégias de mitigação da poluição para melhorar a qualidade do ar em street canyons. Recomenda-se a realização de estudos adicionais considerando as características específicas de cada contexto urbano, assim como o uso de dados reais de monitoramento, para obter resultados mais embasados e precisos.Abstract: Data from 2019 reveal that over 90% of the world's population lives in areas with air pollution levels above the limits established by the World Health Organization (WHO). Human activity, especially in urban areas with a high concentration of industries and vehicle traffic, has been the main cause of air quality degradation and contributes to climate change. Understanding the dispersion of air pollutants in large urban centers is important to change the current scenario and improve the well-being and health of the population. Thus, in this study, a dispersion model for two types of air pollutants, carbon dioxide (CO2) and fine particulate matter (PM2.5), was developed in a hypothetical street canyon. Computational fluid dynamics (CFD) concepts and tools from the Open Source Field Operation and Manipulation (OpenFOAM) software were employed to conduct simulations considering different scenarios, including the presence or absence of trees. The aim was to investigate the impact of urban greening on natural ventilation, dispersion, and influence on CO2 and PM2.5 concentrations. The behavior of pollutants was modeled using the Reynolds-averaged Navier-Stokes equations (RANS) and the k-epsilon turbulence model. The Salome software was used for geometry and computational domain generation, while OpenFOAM was employed to generate the mesh and perform the mathematical calculations. The simulation results were visualized using ParaView software and demonstrated that aerodynamic effects are more significant in scenarios with an initial wind speed of 1 m/s and direction parallel to the main axis of the street. Furthermore, the presence of trees proved to be relevant in reducing the concentrations of the evaluated pollutants. These findings highlight the importance of urban greening and pollution mitigation strategies to improve air quality in street canyons. Further studies are recommended, considering the specific characteristics of each urban context, as well as the use of real monitoring data, to obtain more informed and accurate results

La modelación y la gestión en el mejoramiento de la calidad del aire

This paper provides a review of international trends used in connection with modeling and management of urban air quality. According to specialized literature on this topic, the most common actions are dose-response evaluation, modeling, monitoring, emission control, and planning. The methodology implemented consisted of a procedure for managing measures to control atmospheric pollutants from fixed and mobile sources in order to pursue initiatives aimed at minimizing the risks posed by air pollution to health and the environment. This resulted in an atmospheric emission inventory, which can be used for improving air quality management efforts, and three different kinds of software applications that can be used as technical support tools for receiving, analyzing, and monitoring data. As a conclusion, the procedure for the Environmental Territorial Authority (ETA) to manage measures for controlling atmospheric pollutants from fixed and mobile sources is a promising management tool aimed at minimizing the health and environmental risks associated with air pollutionEl artículo analiza las tendencias internacionales utilizadas sobre la modelación y la gestión implementada en el manejo de la calidad del aire urbano. La literatura especializada establece que las acciones más empleadas son la evaluación dosis-respuesta, modelación, monitoreo, control de emisiones y planificación. La metodología que se implementó fue un procedimiento para la gestión de las medidas de control de contaminantes atmosféricos de fuentes móviles y fijas para adelantar una gestión, orientada a minimizar los riesgos que presenta la contaminación del aire en el ambiente y la salud. Como resultado, se obtiene un inventario de emisiones atmosféricas para mejorar la gestión en el manejo de la calidad del aire, y tres software como soporte técnico para las fases de recepción, análisis y control de datos. Se concluye que el procedimiento para gestionar las medidas de control de contaminantes atmosféricos de fuentes móviles y fijas en la Autoridad Territorial Ambiental (ATA) se perfila como una herramienta de gestión orientada a minimizar los riesgos que presenta la contaminación del aire en el ambiente y la salud

Análisis comparado de los sistemas eléctricos en España y Argentina, 1890-1950. Estrategias globales y experiencias divergentes de la electrificación en dos países de industrialización tardía.

En este WP, se analiza comparativamente la trayectoria de los sistemas eléctricos en España y Argentina desde la instalación de sus primeros servicios urbanos hasta la segunda posguerra mundial. Se parte de que la iniciativa y la financiación de los sistemas eléctricos en los países occidentales fue un proceso tempranamente global, con etapas sucesivas similares, pero condicionado por el entorno local. La convergencia en la trayectoria de ambas industrias se hace evidente al comparar su arranque y ritmo de crecimiento. No obstante, tras de examinar otras variables, como los recursos disponibles, la estructura y dimensión de los mercados, los mecanismos de regulación pública y los modelos de inversión, se concluye que la aparente coincidencia encubre dos modalidades diversas de electrificación tardía: alta rentabilidad y concentración territorial en Argentina y una electrificación más armónica, aunque de menor rendimiento y rentabilidad, en España. Aquí, se analizan sus orígenes y se apuntan algunas secuelas de estas trayectorias disímiles