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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Méthodes coopératives de localisation de véhicules / Cooperative methods for vehicle localization

Rohani, Mohsen January 2015 (has links)
Abstract : Embedded intelligence in vehicular applications is becoming of great interest since the last two decades. Position estimation has been one of the most crucial pieces of information for Intelligent Transportation Systems (ITS). Real time, accurate and reliable localization of vehicles has become particularly important for the automotive industry. The significant growth of sensing, communication and computing capabilities over the recent years has opened new fields of applications, such as ADAS (Advanced driver assistance systems) and active safety systems, and has brought the ability of exchanging information between vehicles. Most of these applications can benefit from more accurate and reliable localization. With the recent emergence of multi-vehicular wireless communication capabilities, cooperative architectures have become an attractive alternative to solving the localization problem. The main goal of cooperative localization is to exploit different sources of information coming from different vehicles within a short range area, in order to enhance positioning system efficiency, while keeping the cost to a reasonable level. In this Thesis, we aim to propose new and effective methods to improve vehicle localization performance by using cooperative approaches. In order to reach this goal, three new methods for cooperative vehicle localization have been proposed and the performance of these methods has been analyzed. Our first proposed cooperative method is a Cooperative Map Matching (CMM) method which aims to estimate and compensate the common error component of the GPS positioning by using cooperative approach and exploiting the communication capability of the vehicles. Then we propose the concept of Dynamic base station DGPS (DDGPS) and use it to generate GPS pseudorange corrections and broadcast them for other vehicles. Finally we introduce a cooperative method for improving the GPS positioning by incorporating the GPS measured position of the vehicles and inter-vehicle distances. This method is a decentralized cooperative positioning method based on Bayesian approach. The detailed derivation of the equations and the simulation results of each algorithm are described in the designated chapters. In addition to it, the sensitivity of the methods to different parameters is also studied and discussed. Finally in order to validate the results of the simulations, experimental validation of the CMM method based on the experimental data captured by the test vehicles is performed and studied. The simulation and experimental results show that using cooperative approaches can significantly increase the performance of the positioning methods while keeping the cost to a reasonable amount. / Résumé : L’intelligence embarquée dans les applications véhiculaires devient un grand intérêt depuis les deux dernières décennies. L’estimation de position a été l'une des parties les plus cruciales concernant les systèmes de transport intelligents (STI). La localisation précise et fiable en temps réel des véhicules est devenue particulièrement importante pour l'industrie automobile. Les améliorations technologiques significatives en matière de capteurs, de communication et de calcul embarqué au cours des dernières années ont ouvert de nouveaux champs d'applications, tels que les systèmes de sécurité active ou les ADAS, et a aussi apporté la possibilité d'échanger des informations entre les véhicules. Une localisation plus précise et fiable serait un bénéfice pour ces applications. Avec l'émergence récente des capacités de communication sans fil multi-véhicules, les architectures coopératives sont devenues une alternative intéressante pour résoudre le problème de localisation. L'objectif principal de la localisation coopérative est d'exploiter différentes sources d'information provenant de différents véhicules dans une zone de courte portée, afin d'améliorer l'efficacité du système de positionnement, tout en gardant le coût à un niveau raisonnable. Dans cette thèse, nous nous efforçons de proposer des méthodes nouvelles et efficaces pour améliorer les performances de localisation du véhicule en utilisant des approches coopératives. Afin d'atteindre cet objectif, trois nouvelles méthodes de localisation coopérative du véhicule ont été proposées et la performance de ces méthodes a été analysée. Notre première méthode coopérative est une méthode de correspondance cartographique coopérative (CMM, Cooperative Map Matching) qui vise à estimer et à compenser la composante d'erreur commune du positionnement GPS en utilisant une approche coopérative et en exploitant les capacités de communication des véhicules. Ensuite, nous proposons le concept de station de base Dynamique DGPS (DDGPS) et l'utilisons pour générer des corrections de pseudo-distance GPS et les diffuser aux autres véhicules. Enfin, nous présentons une méthode coopérative pour améliorer le positionnement GPS en utilisant à la fois les positions GPS des véhicules et les distances inter-véhiculaires mesurées. Ceci est une méthode de positionnement coopératif décentralisé basé sur une approche bayésienne. La description détaillée des équations et les résultats de simulation de chaque algorithme sont décrits dans les chapitres désignés. En plus de cela, la sensibilité des méthodes aux différents paramètres est également étudiée et discutée. Enfin, les résultats de simulations concernant la méthode CMM ont pu être validés à l’aide de données expérimentales enregistrées par des véhicules d'essai. La simulation et les résultats expérimentaux montrent que l'utilisation des approches coopératives peut augmenter de manière significative la performance des méthodes de positionnement tout en gardant le coût à un montant raisonnable.
102

Cloud computing based adaptive traffic control and management

Jaworski, P. January 2013 (has links)
Recent years have shown a growing concern over increasing traffic volume worldwide. The insufficient road capacity and the resulting congestions have become major problems in many urban areas. Congestions negatively impact the economy, the environment and the health of the population as well as the drivers satisfaction. Current solutions to this topical and timely problem rely on the exploitation of Intelligent Transportation Systems (ITS) technologies. ITS urban traffic management involves the collection and processing of a large amount of geographically distributed information to control distributed infrastructure and individual vehicles. The distributed nature of the problem prompted the development of a novel, scalable ITS-Cloud platform. The ITS-Cloud organises the processing and manages distributed data sources to provide traffic management methods with more accurate information about the state of the traffic. A new approach to service allocation, derived from the existing cloud and grid computing approaches, was created to address the unique needs of ITS traffic management. The ITS-Cloud hosts the collection of software services that form the Cloud based Traffic Management System (CTMS). CTMS combines intersection control algorithms with intersection approach advices to the vehicles and dynamic routing. The CTMS contains a novel Two-Step traffic management method that relies on the ITS-Cloud to deliver a detailed traffic simulation image and integrates an adaptive intersection control algorithm with a microscopic prediction mechanism. It is the first method able to perform simultaneous adaptive intersection control and intersection approach optimization. The Two-Step method builds on a novel pressure based adaptive intersection control algorithm as well as two new traffic prediction schemes. The developed traffic management system was evaluated using a new microscopic traffic simulation tool tightly integrated with the ITS-Cloud. The novel traffic management approaches were shown to outperform benchmark methods for a realistic range of traffic conditions and road network configurations. Unique to the work was the investigation of interactions between ITS components.
103

A stepwise approach towards achieving a multimodal platform within the context of the CoCT’s land transport networks

Struwig, Claudia Bernadine 03 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The importance of transport should not be underestimated. Transport progresses a person’s quality of life: it connects people to one another and provides access to work, services and recreational opportunities. However, post-apartheid South Africa is unfortunately still faced with a legacy of segregation. While the less-privileged, who mostly live at the fringe of Central Business Districts (CBDs), are captive users of public transport, the private vehicle trend, under the privileged, is becoming more evident. This research project thus proposes that a balanced and integrated sustainable transport system be promoted. That is, one that will aid South Africa in growing and improving its general socio-economical status by providing all its citizens with (equal) access to a balanced transport network. It is believed that, if a multimodal system is promoted, the deficiencies of the current heterogeneous non-integrated systems may be overcome. Therefore, if South Africa’s transport network is augmented with a multimodal platform, the nation will be able to move its citizens effectively and efficiently, without jeopardising the economy, social matters and the environment, today and in the future. Moreover, South Africa will also have the necessary stimulus to utilise the already available resources at its disposal by working together as ‘one’. This research project thus stipulates a (generic) sequential approach needed in achieving an integrated (sustainable) public transport system. The goal of this research project is to create awareness of the benefits that may arise from, and the implementation steps required in obtaining, such a multimodal platform. The focus area for researching the proposition made herein is the City of Cape Town’s (CoCT’s) land transport networks. The City has a management facility, with resultant transport data repository, known as the Transport Management Centre (TMC). This TMC is regarded as one of the finest state of the art facilities in the world and the features thereof offer a sufficient base and point of departure for the promotion of a multimodal transport system. By conducting research in this field, the following portraying aspects, needed for the realisation of the proposition made herein, were found. Firstly, in order to obtain an integrated sustainable transport system, the appropriate Intelligent Transport Systems (ITS) need to be integrated. It is believed that, if an intelligent transport scheme, grounded on ITS applications, is advocated, the City will be in the position to more effectively monitor what is going on, to more accurately predict what might happen in the future, and to manage its transport system proactively on an area-wide basis. Secondly, in order to meet the integration requirements imposed by multimodal transport, a centralised database needs to be created. With such a database in place, information sharing across all modes of private- and public land transport, and thus also between the investors or the operators, will be possible. An example of such a database was developed in Microsoft Access and the modes considered therein are: MyCiti, Metrorail and Golden Arrow Bus Service (GABS). The data stored in this database is historic, but the incorporation of real time information was also catered for. Thirdly, it is believed that the success of the City’s transport system, and the development of a multimodal system, is dependent on the provision of an efficient Advanced Traveller Information System (ATIS). The idea is to promote multimodal transport as a convenient transit option by providing travellers with information on journey planning that aims to counteract their reluctance to change. In order to develop such a multimodal Journey Planner (JP), the unimodal networks considered herein were combined into a supernetwork on which Dijkstra’s Shortest Path Algorithm was applied. This algorithm was programmed in Microsoft Excel’s Visual Basic for Applications (VBA) and it incorporates the following user criteria: the origin, the destination, the user’s mode preference, and the user’s optimisation preference of either time or distance. In conclusion, it can be argued that, with information becoming such a vital commodity in everyday life, the catering for informed travellers are the key to successful future transport services. If travellers are informed about the transport networks’ performance, a positive attitude is fostered. Moreover, by providing travellers with information on journey planning, their feelings of uncertainty and fear of the unknown, that are present in (especially) public transport services, may be neutralised. This information will give the public carte blanche to make decisions that give them the perception of having more ‘control over their lives’. Therefore, if a multimodal JP that can be accessed from one portal is created, people’s inclination to acquire more information will be met. And as a result, traversing in an integrated manner may become the norm. / AFRIKAANSE OPSOMMING: Die belangrikheid van vervoer mag nie onderskat word nie. Vervoer speel ’n belangrike rol in die bevordering van ’n persoon se lewenskwaliteit: dit verbind mense met mekaar en verskaf toegang tot die werksplek, diensteverskaffers, en vryetydsbesteding. Post-apartheid Suid-Afrika is egter nog steeds vasgevang in ’n nalatenskap van rasseskeiding. Die minderbevoorregtes, wat meestal aan die buitewyke van die stad woon, is geforseerde gebruikers van openbare vervoer, terwyl die neiging (onder die bevoorregtes) om privaatvoertuie te gebruik, aan die toeneem is. Hierdie navorsingsprojek beveel dus aan dat ’n gebalanseerde, geïntegreerde en volhoubare vervoerstelsel bevorder moet word. ’n Sodanige stelsel sal help om die sosio-ekonomiese status van Suid-Afrika te bevorder. Dít kan net bereik word as alle landsburgers gelyke toegang tot ’n gebalanseeerde vervoernetwerk het. As ’n multimode-stelsel dus bevorder word, kan die tekortkominge van die huidige heterogene, nie-geïntegreerde stelsels oorkom word. Indien Suid-Afrika se vervoernetwerk ’n multimodale platform het, kan die landsburgers effektief en doeltreffend vervoer word sonder om die ekonomie, sosiale aangeleenthede of omgewing, tans en in die toekoms, in gedrang in te bring. Suid-Afrika sal boonop, met so ’n platform in plek, ook die nodige stimulus hê om die bestaande hulpbronne optimaal te gebruik. Hierdie navorsingsprojek verskaf ’n (generiese) in-volgorde-benadering om ’n volhoubare, geïntegreerde openbare vervoerstelsel daar te stel. Die doel is om bewustheid van die voordele wat uit ’n multimodale platform spruit, sowel as die nodige stappe vir die uitvoering daarvan, te kweek. Die fokusarea van die navorsing is die Stad van Kaapstad se land-vervoernetwerke. Die Stad het ’n beheerfasiliteit waar vervoerdata versamel word. Dit staan bekend as die vervoer-beheersentrum (TMC: Transport Management Centre). Hierdie fasiliteit word as toonaangewend in die wêreld beskou. Die kenmerkende eienskappe van hierdie fasiliteit bied verder ook ’n goeie vertrekpunt vir die bevordering van ’n multimodale stelsel. Die navorsing in hierdie veld het die volgende bydraende faktore, wat benodig word om die voorstelling te realiseer, geïdentifiseer. In die eerste plek moet die intelligente vervoerstelsels (ITS: Intelligent Transport Systems) geïntegreer word om ’n geïntegreerde volhoubare vervoerstelsel daar te stel. Indien ’n intelligente vervoerskema, gebaseer op tegnologiese inisiatiewe, aangemoedig word, sal die Stad van Kaapstad in die posisie wees om sy vervoerstelsel pro-aktief te bestuur deur meer effektief te monitor wat aangaan en meer akkuraat te voorspel wat in die toekoms mag gebeur. Tweedens moet daar ’n gesentraliseerde databasis geskep word. Met hierdie databasis sal die nodige integrasievereistes vir ’n multimodale vervoerstelsel, bereik word. Inligting kan dan gedeel word tussen privaat- en openbare landvervoer, asook tussen die beleggers en die operateurs van die verskillende vervoermodusse. ’n Voorbeeld van so ’n databasis is in Microsoft Access geskep en die modusse wat deel daarvan uitmaak, is: MyCiti, Metrorail en Golden Arrow Bus Services (GABS). Die data wat hierin vervat is, is histories, maar daar is vir intydse inligting voorsiening gemaak. In die derde plek is die sukses van die Stad van Kaapstad se vervoerstelsel en die ontwikkeling van ’n multimodale stelsel afhanklik van die daarstelling van ’n effektiewe, gevorderde inligtingsstelsel vir pendelaars (ATIS: Advanced Traveller Information Systems). Die idee is om ’n multimodale vervoerstelsel as ’n gerieflike opsie onder pendelaars te bevorder. Dit kan bereik word deur inligting rakende reisbeplanning aan pendelaars daar te stel. Met die verkryging van sodanige kennis sal die pendelaar se weerstand teen verandering ook afneem. Om so ’n multimodale reisbeplanner (JP: Journey Planner) te ontwikkel, is die eenmodaal-netwerke gekombineer om ’n supernetwerk te skep. Dijkstra se algoritme is op die supernetwerk toegepas. Die algoritme is in Microsoft Excel se VBA (Visual Basic for Applications) geprogrammeer en dit bevat die volgende gebruikerskriteria, nl. die begin- en eindpunt, die gebruiker se modes-voorkeur en die gebruiker se gekose optimeringsvoorkeur van tyd of afstand. Ten slotte kan gesê word dat inligting ’n groot rol in die mens se daaglikse lewe en aktiwiteite speel. Daar kan dus geredeneer word dat die sleutel tot suksesvolle vervoerdienste daarin lê om vir ingeligte pendelaars voorsiening te maak. As pendelaars ingelig is oor die stand van die vervoernetwerk maak dit hul houding meer positief. Verder, as pendelaars ook inligting oor reisbeplanning het, kan dit hul gevoel van onsekerheid en vrees jeens (veral) openbare vervoer teenwerk. Met al hierdie inligting tot sy beskikking kan ’n persoon dus sy eie keuses maak en dit lei daartoe dat die persoon meer in beheer voel. As ’n multimodale JP geskep word, voed dit die mens se begeerte vir meer inligting. En met ’n sodanige JP in plek, kan geïntegreerde pendel moontlik die norm word.
104

A video-based traffic monitoring system

Magaia, Lourenco Lazaro 12 1900 (has links)
Thesis (PhD (Mathematical Sciences. Applied Mathematics))--University of Stellenbosch, 2006. / This thesis addresses the problem of bulding a video-based traffic monitoring system. We employ clustering, trackiing and three-dimensional reconstruction of moving objects over a long image sequence. We present an algorithms that robustly recovers the motion and reconstructs three-dimensional shapes from a sequence of video images, Magaia et al [91]. The problem ...
105

Development of GIS-based advanced traveler information system (ATIS) in Hong Kong

黃秀貞, Wong, Sau-ching, Pauline. January 2002 (has links)
published_or_final_version / Urban Planning / Master / Master of Science in Urban Planning
106

Architecture fonctionnelle pour la planification des trajectoires des véhicules automatisés dans des environnements complexes / Functional architecture for automated vehicles trajectory planning in complex environments

González Bautista, David 03 April 2017 (has links)
Un des buts de la recherche et du développement des systèmes de transport intelligents est d'augmenter le confort et la sécurité des passagers, tout en réduisant la consommation d'énergie, la pollution de l'air et le temps de déplacement. L'introduction de voitures complètement autonomes sur la voie publique nécessite la résolution d'un certain nombre de problèmes techniques et en particulier de disposer de modules de planification de trajectoire robustes. Ce travail de thèse s'inscrit dans ce cadre. Il propose une architecture modulaire pour la planification de trajectoire d'un véhicule autonome. La méthode permet de générer des trajectoires constituées de courbes interpolées adaptées à des environnements complexes comme des virages, des ronds-points, etc., tout en garantissant la sécurité et le confort des passagers. La prise en compte de l'incertitude des systèmes de perception, des limites physiques du véhicule, de la disposition des routes et des règles de circulation est aussi assurée dans le calcul de la trajectoire. L'algorithme est capable de modifier en temps réel la trajectoire prédéfinie de façon à éviter les collisions. Le calcul de la nouvelle trajectoire maintient les accélérations latérales à leur minimum, assurant ainsi le confort du passager. L'approche proposée a été évaluée et validée dans des environnements simulés et sur des véhicules réels. Cette méthode permet d'éviter les obstacles statiques et dynamiques repérés par le système de perception.Un système d'aide à la conduite pour le contrôle partagé basé sur cette architecture est introduit. Il prend en compte l'arbitrage, la surveillance et le partage de la conduite tout en maintenant le conducteur dans la boucle de contrôle. Il laisse le conducteur agir tant qu'il n'y a pas de danger et interagit avec le conducteur dans le cas contraire. L'algorithme se décompose donc en deux processus : 1) évaluation du risque et, s'il y a un risque avéré 2) partage du contrôle à l'aide de signaux haptiques via le volant.La méthode de planification de trajectoire présentée dans cette thèse est modulaire et générique. Elle peut être intégrée facilement dans toute architecture d'un véhicule autonome. / Developments in the Intelligent Transportation Systems (ITS) field show promising results at increasing passengers comfort and safety, while decreasing energy consumption, emissions and travel time. In road transportation, the appearance of automated vehicles is significantly aiding drivers by reducing some driving-associated tedious tasks. However, there is still a long way to go before making the transition between automated vehicles (i.e. vehicles with some automated features) and autonomous vehicles on public roads (i.e. fully autonomous driving), specially from the motion planning point of view. With this in mind, the present PhD thesis proposes the design of a generic modular architecture for automated vehicles motion planning. It implements and improves curve interpolation techniques in the motion planning literature by including comfort as the main design parameter, addressing complex environments such as turns, intersections and roundabouts. It will be able to generate suitable trajectories that consider measurements' incertitude from the perception system, vehicle’s physical limits, the road layout and traffic rules. In case future collision states are detected, the proposed approach is able to change---in real-time---the current trajectory and avoid the obstacle in front. It permits to avoid obstacles in conflict with the current trajectory of the ego-vehicle, considering comfort limits and developing a new trajectory that keeps lateral accelerations at its minimum. The proposed approach is tested in simulated and real urban environments, including turns and two-lane roundabouts with different radii. Static and dynamic obstacles are considered as to face and interact with other road actors, avoiding collisions when detected. The functional architecture is also tested in shared control and arbitration applications, focusing in keeping the driver in the control loop to addition the system's supervision over drivers’ knowledge and skills in the driving task. The control sharing advanced driver assistance system (ADAS) is proposed in two steps: 1) risk assessment of the situation in hand, based on the optimal trajectory and driving boundaries identified by the motion planning architecture and; 2) control sharing via haptic signals sent to the driver through the steering wheel. The approach demonstrates the modularity of the functional architecture as it proposes a general solution for some of today's unsolved challenges in the automated driving field.
107

Investigating the impact of recurrent and non-recurrent congestion on highway operations

Unknown Date (has links)
Traffic congestion is one of the most concerning issues in the transportation system. Recurrent congestion and non-recurrent congestion are explored in this research. This research will investigate one of the most concerning issues with the transportation system, congestion, using an overall delay analysis study. A developed fused database program was used to access and analyze the complete database data. Two online databases were used for obtaining traffic, incident and weather data. Eleven different scenarios such as peak-hours, rain scenario, incidents scenario, and work zone scenario were developed for the analysis. An overall delay study was performed on all scenarios to find the impact recurring and non-recurring congestion on the highway. The results of this research were interesting for future adjustment and improvements on the two segments of highways selected. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection
108

Framework for Integration of the Driving Simulator in Connected Vehicle Environment

Unknown Date (has links)
Research on connected vehicles (CV) has attracted attention in the last decade due to numerous potential applications and challenges related to exchange of information between the vehicles (and infrastructure). Most of the relevant studies focus on these applications and challenges with the help of novel or existing simulation frameworks. The simulation framework often contains the mobility and communication components, and these components are frequently simplified. In this study, the authors aim to provide the detailed information for developing a fully V2X capable infrastructure within the lab environment. The physical components of the proposed infrastructure include: (i) userdriven Driving Simulator (DS) with the embedded micro-simulation tool (MS); (ii) external traffic signal controller (TSC); (iii) Road Side Unit (RSU) and omnidirectional antenna attached to RSU; (iv) On-Board Unit (OBU) that is integrated within DS‘s cockpit. The proposed framework can be used for advanced applications in the context of connected vehicles. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection
109

Veículo-sensor: estado da arte e proposta de método orientativo para especificação do sistema de posicionamento veicular. / Vehicle as a sensor: state of the art and proposition of an orientative method to specify the vehicular positioning system.

Oliveira, Rafael Henrique de 07 August 2017 (has links)
Plataformas móveis, como smartphones, tablets e também veículos, têm cada vez mais possibilitado a coleta e análise de dados de seu entorno. Essa oportunidade de sensoriamento de diferentes fenômenos oferece maior cobertura espaço-temporal a menor custo em relação às técnicas tradicionais. O dinamismo dessa abordagem traz desafios relacionados ao posicionamento desses sensores e ao georreferenciamento das informações coletadas. Desta forma, a presente pesquisa tem como objetivo propor método orientativo de especificação de técnicas de posicionamento no contexto do uso do veículo enquanto sensor. Inicialmente, a partir de levantamento bibliográfico, caracteriza-se a evolução do conceito de veículo-sensor e seu emprego no sensoriamento da fluidez do tráfego, das condições do pavimento, de qualidade do ar, entre outras variáveis. Descreve-se o estado da arte nesse campo de pesquisa, identificando lacunas e pontos a serem mais bem estudados. Em um segundo momento, identificando o posicionamento como tópico pouco discutido nesse contexto, o trabalho dedica-se à definição de método orientativo de especificação de sistemas de posicionamento para veículossensores, tendo em conta os requisitos associados às diferentes variáveis a serem sensoriadas. Ao fim, apresenta-se estudo de campo referente ao uso de veículos na identificação de ocorrência de lombadas, empregando as ferramentas estabelecidas nessa dissertação e pormenorizando a discussão do sistema de posicionamento. Dessa forma, o trabalho contribui para a caracterização dos sistemas de sensoriamento baseados em veículos e a identificação do posicionamento como parâmetro fundamental para a qualidade desses sistemas. / Mobile devices such as smartphones, tablets and also vehicles have increasingly enabled gathering and analysing data from its environment. This opportunity of sensing different phenomena offers greater spatiotemporal coverage at less cost when compared to the traditional techniques. The dynamics of this approach has challenges related to the positioning of this sensors and the georeferencing of sensed data. Thus, this research aims to propose an orientative method to specify the positioning system for use with vehicles working as mobile sensors. Firstly, by doing a literature review, the purpose is to characterize the evolution of the concept of vehicle as a mobile sensor and its use in sensing traffic conditions, road conditions, air quality and other variables. The state of the art in this research field is described and the gaps and open questions are identified. In a second moment, after identifying the positioning in this context as an understudied area, this research will work on discussing an orientative method to specify the positioning system considering specificities and requirements associated with the different sensored phenomena. At the end, this work describes an exploratory study using a vehicle to identify road bumps, applying the tools defined in the method and detailing the discussion about the positioning system. Therefore, this work contributes to the characterization of sensing systems based on vehicles and the identification of the vehicular positioning as a fundamental parameter for the quality of these systems.
110

Discrete Event System Modeling Of Demand Responsive Transportation Systems Operating In Real Time

Yankov, Daniel Y 18 March 2008 (has links)
Demand responsive transportation is a variable route service of passengers or freight from specific origin(s) to destination(s) in response to the request of users. Operational planning of DRT system encompasses the methods to provide efficient service to the passengers and to the system operators. These methods cover the assignments of vehicles to transportation requests and vehicle routings under various constraints such as environmental conditions, traffic and service limitations. Advances in the information and communication technologies, such as the Internet, mobile communication devices, GIS, GPS, Intelligent Transportation Systems have led to a significantly complex and highly dynamical decision making environment. Recent approaches to DRT operational planning are based on "closed information loop" to achieve a higher level of automation, increased flexibility and efficiency. Intelligent and effective use of the available information in such a complex decision making environment requires the application of formal modeling and control approaches, which are robust, modular and computationally efficient. In this study, DRT systems are modeled as Discrete Event Systems using Finite Automata formalism and DRT real time control is addressed using Supervisory Control Theory. Two application scenarios are considered; the first is based on air-charter service and illustrates uncontrolled system model and operational specification synthesis. The automatic synthesis of centralized and modular supervisors is demonstrated. The second scenario is a mission critical application based on emergency evacuation problem. Decentralized supervisory control architecture suitable for accommodating the real-time contingencies is presented. Conditions for parallel computation of local supervisors are specified and the computational advantages of alternative supervisory control architectures are discussed. Discrete event system modeling and supervisory control theory are well established and powerful mathematical tools. In this dissertation, they are shown to be suitable for expressing the modeling and control requirements of complex and dynamic applications in DRT. The modeling and control approaches described herein, coupled with the mature body of research literature in Discrete Event Systems and Supervisory Control Theory, facilitate logical analysis of these complex systems and provide the necessary framework for development of intelligent decision making tools for real time operational planning and control in a broad range of DRT applications.

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