Decision-making for Vehicle Path Planning

This dissertation presents novel algorithms for vehicle path planning in scenarios where the environment changes. In these dynamic scenarios the path of the vehicle needs to adapt to changes in the real world. In these scenarios, higher performance paths can be achieved if we are able to predict the future state of the world, by learning the way it evolves from historical data. We are relying on recent advances in the field of deep learning and reinforcement learning to learn appropriate world models and path planning behaviors. There are many different practical applications that map to this model. In this dissertation we propose algorithms for two applications that are very different in domain but share important formal similarities: the scheduling of taxi services in a large city and tracking wild animals with an unmanned aerial vehicle. The first application models a centralized taxi dispatch center in a big city. It is a multivariate optimization problem for taxi time scheduling and path planning. The first goal here is to balance the taxi service demand and supply ratio in the city. The second goal is to minimize passenger waiting time and taxi idle driving distance. We design different learning models that capture taxi demand and destination distribution patterns from historical taxi data. The predictions are evaluated with real-world taxi trip records. The predicted taxi demand and destination is used to build a taxi dispatch model. The taxi assignment and re-balance is optimized by solving a Mixed Integer Programming (MIP) problem. The second application concerns animal monitoring using an unmanned aerial vehicle (UAV) to search and track wild animals in a large geographic area. We propose two different path planing approaches for the UAV. The first one is based on the UAV controller solving Markov decision process (MDP). The second algorithms relies on the past recorded animal appearances. We designed a learning model that captures animal appearance patterns and predicts the distribution of future animal appearances. We compare the proposed path planning approaches with traditional methods and evaluated them in terms of collected value of information (VoI), message delay and percentage of events collected

Fusion of Large Continuously Collected Data Sources: Understanding Travel Demand Trends and Measuring Transport Project Impacts

This research combines several large, continuously collected data sets to understand recent travel demand trends in San Francisco, and it develops a tool for measuring transport project impacts. Because they are continuously collected, these data provide an opportunity to measure change in a way that is not available in traditional, cross-sectional travel surveys. The data used are from San Francisco and cover performance of the transit system and associated factors expected to drive transit demand. This study employs a two stage methodology to derive insight from these data. First, a performance monitoring tool is developed to process the raw data and report meaningful performance indicators. This tool encapsulates the necessary data cleaning functionality, and manages a multi-stage data expansion process to ensure that data are representative of the system as a whole. Second, time series models of transit ridership are estimated from the outputs of the performance monitoring tool. These time series models provide a means of quantifying the portion of the ridership changes due to service changes versus background factors, such as employment growth. The estimated models are applied to understand the drivers of recent ridership trends in the San Francisco, where ridership on the San Francisco Municipal Railway (MUNI) bus system remains flat in spite of population and employment growth, while ridership on the Bay Area Rapid Transit (BART) system grows faster than employment. In addition, the models are applied to several planning case studies, including both ex-post ridership evaluations and short-term forecasting applications. The outcome of this research is to establish and test a tool to facilitate the use of passively collected data for retrospective travel demand analyses. It provides insight into the effects of transport projects, and lays the groundwork for a future studies that further our ability to observe and understand travel behaviour

Benelux meeting on systems and control, 23rd, March 17-19, 2004, Helvoirt, The Netherlands

Book of abstract

Aeronautical Engineering: A continuing bibliography with indexes

This bibliography lists 512 reports, articles and other documents introduced into the NASA scientific and technical information system in April 1982

De la Routine Humaine vers des Réseaux Mobiles Plus Efficaces

The proliferation of pervasive communication caused a recent boost up on the mobile data usage, which network operators are not always prepared for. The main origin of the mobile network demands are smartphone devices. From the network side those devices may be seen as villains for imposing an enormous traffic, but from the analytical point of view they provide today the best means of gathering users information about content consumption and mobility behavior on a large scale. Understanding users' mobility and network behavior is essential in the design of efficient communication systems. We are routinary beings. The routine cycles on our daily lives are an essential part of our interface with the world. Our habits define, for instance, where we are going Saturday night, or what is the typical website for the mornings of Monday. The repetitive behavior reflects on our mobility patterns and network activities. In this thesis we focus on metropolitan users generating traffic demands during their normal daily lives. We present a detailed study on both users' routinary mobility and routinary network behavior. As a study of case where such investigation can be useful, we propose a hotspot deployment strategy that takes into account the routine aspects of people's mobility.We first investigate urban mobility patterns. We analyze large-scale datasets of mobility in different cities of the world, namely Beijing, Tokyo, New York, Paris, San Francisco, London, Moscow and Mexico City. Our contribution is this area is two-fold. First, we show that there is a similarity on people's mobility behavior regardless the city. Second, we unveil three characteristics present on the mobility of typical urban population: repetitiveness, usage of shortest-paths, and confinement. Those characteristics undercover people's tendency to revisit a small portion of favorite venues using trajectories that are close to the shortest-path. Furthermore, people generally have their mobility restrict to a dozen of kilometers per day.We then investigate the users' traffic demands patterns. We analyze a large data set with 6.8 million subscribers. We have mainly two contributions in this aspect. First, a precise characterization of individual subscribers' traffic behavior clustered by their usage patterns. We see how the daily routine impacts on the network demands and the strong similarity between traffic on different days. Second, we provide a way for synthetically, still consistently, reproducing usage patterns of mobile subscribers. Synthetic traces offer positive implications for network planning and carry no privacy issues to subscribers as the original datasets.To assess the effectiveness of these findings on real-life scenario, we propose a hotspot deployment strategy that considers routine characteristics of mobility and traffic in order to improve mobile data offloading. Carefully deploying Wi-Fi hotspots can both be cheaper than upgrade the current cellular network structure and can concede significant improvement in the network capacity. Our approach increases the amount of offload when compared to other solution from the literature.L’omniprésence des communications a entraîné une récente augmentation des volumes de données mobiles, pour laquelle les opérateurs n’étaient pas toujours préparés. Les smartphones sont les plus gros consommateurs de données mobiles. Ces appareils peuvent être considérés comme méchants à cause d’un tel traffic, mais d’un point de vue analytique ils fournissent, aujourd’hui un des meilleurs moyens afin de collecter les données sur le comportement de consommation et de mobilité de grande échelle. Comprendre le comportement des utilisateurs sur leur mobilité et leur connectivité est nécessaire à la création d’un système de communication effectifs. Nous sommes routiniers. Ces cycles routiniers sont une grande partie de nos interactions avec le monde. Par exemple, nos habitudes definissent ce que l’on va faire le samedi ou les sites que nous consultons le lundi matin. Ces comportements répétés reflètent nos déplacements et activités en ligne. Dans cette thèse, nous allons nous concentrer sur les demandes de traffic générées par les usagers métropolitains durant leurs activités quotidiennes. Nous présentons une étude détaillée des usagers selon les comportements routiniers de mobilité ou d’activité sur internet. Dans une étude de cas, ou cette enquête serait utile, nous proposons une stratégies de déploiement de points de accès qui prendra en compte les aspects routiniers de la mobilités des utilisateurs.Nous étudirons en premier lieu, les modèles de mobilité en milieu urbain. Nous analyserons les données de mobilité à grande échelle dans de grandes villes comme Beijing, Tokyo, New York, Paris, San Francisco, London, Moscow, Mexico City. Cette contribution se fait en deux étapes. Premièrement, nous observerons les similitudes des déplacements peu importe la ville concernée. Ensuite, nous mettrons en évidence trois caractéristiques présentes dans les déplacements d’une population urbaine typique: Répétivité, utilisation de raccourcis, confinement. Ces caractéristiques sont dues à la tendance qu’ont les personnes à revisiter les même rues en utilisant les trajectoires proches du chemin le plus court. D’ailleurs, les personnes ont une mobilité quotidienne inférieure à dix kilomètres par jour.Nous avons ensuite étudié les modèles de demandes de traffic en utilisant une base de données comprenant les données de 6.8 millions d’utilisateurs. Pour cela nous avons principalement deux contributions. Premièrement, une caractérisation précise des comportements de consommation des utilisateurs agrégés par modèle. Nous pouvons voir comment les routines quotidiennes impactent nos demandes de connections et la similarité de ce traffic en fonction des jours. En suite, nous fournirons un moyen de reproduire artificiellement mais avec cohérence les modèles des utilisateurs de données mobiles. Ces données synthétisées ont l’avantage de permettre la planification du réseau sans information sur la vie privées de utilisateurs comme les bases de données d’origine.Afin d’évaluer l’efficacité de ces informations dans un scénario grandeur nature, nous proposerons une stratégie de deploiement de points de accès qui prend en compte les caractéristiques routinières en terme de déplacement et de demande de trafic dans le but d’améliorer la décharge de données mobile. Déployer correctement des points de accès WiFi peut être moins cher que d’améliorer l’infrastructure de réseaux mobiles, et peut permettre d’améliorer considérablement la capacité du réseau. Notre approche améliore l’évacuation de trafic comparée aux autres solutions disponibles dans la littérature

Aeronautical engineering: A continuing bibliography with indexes, supplement 139

This bibliography lists 381 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1981

VANET-enabled eco-friendly road characteristics-aware routing for vehicular traffic

There is growing awareness of the dangers of climate change caused by greenhouse gases. In the coming decades this could result in numerous disasters such as heat-waves, flooding and crop failures. A major contributor to the total amount of greenhouse gas emissions is the transport sector, particularly private vehicles. Traffic congestion involving private vehicles also causes a lot of wasted time and stress to commuters. At the same time new wireless technologies such as Vehicular Ad-Hoc Networks (VANETs) are being developed which could allow vehicles to communicate with each other. These could enable a number of innovative schemes to reduce traffic congestion and greenhouse gas emissions. 1) EcoTrec is a VANET-based system which allows vehicles to exchange messages regarding traffic congestion and road conditions, such as roughness and gradient. Each vehicle uses the messages it has received to build a model of nearby roads and the traffic on them. The EcoTrec Algorithm then recommends the most fuel efficient route for the vehicles to follow. 2) Time-Ants is a swarm based algorithm that considers not only the amount of cars in the spatial domain but also the amoumt in the time domain. This allows the system to build a model of the traffic congestion throughout the day. As traffic patterns are broadly similar for weekdays this gives us a good idea of what traffic will be like allowing us to route the vehicles more efficiently using the Time-Ants Algorithm. 3) Electric Vehicle enhanced Dedicated Bus Lanes (E-DBL) proposes allowing electric vehicles onto the bus lanes. Such an approach could allow a reduction in traffic congestion on the regular lanes without greatly impeding the buses. It would also encourage uptake of electric vehicles. 4) A comprehensive survey of issues associated with communication centred traffic management systems was carried out

Aeronautical Engineering: A continuing bibliography, 1982 cumulative index

This bibliography is a cumulative index to the abstracts contained in NASA SP-7037 (145) through NASA SP-7037 (156) of Aeronautical Engineering: A Continuing Bibliography. NASA SP-7037 and its supplements have been compiled through the cooperative efforts of the American Institute of Aeronautics and Astronautics (AIAA) and the National Aeronautics and Space Administration (NASA). This cumulative index includes subject, personal author, corporate source, contract, and report number indexes

Research and technology, 1992

Selected research and technology activities at Ames Research Center, including the Moffett Field site and the Dryden Flight Research Facility, are summarized. These activities exemplify the Center's varied and productive research efforts for 1992