15,925 research outputs found

    Trajectory Clustering and an Application to Airspace Monitoring

    Get PDF
    This paper presents a framework aimed at monitoring the behavior of aircraft in a given airspace. Nominal trajectories are determined and learned using data driven methods. Standard procedures are used by air traffic controllers (ATC) to guide aircraft, ensure the safety of the airspace, and to maximize the runway occupancy. Even though standard procedures are used by ATC, the control of the aircraft remains with the pilots, leading to a large variability in the flight patterns observed. Two methods to identify typical operations and their variability from recorded radar tracks are presented. This knowledge base is then used to monitor the conformance of current operations against operations previously identified as standard. A tool called AirTrajectoryMiner is presented, aiming at monitoring the instantaneous health of the airspace, in real time. The airspace is "healthy" when all aircraft are flying according to the nominal procedures. A measure of complexity is introduced, measuring the conformance of current flight to nominal flight patterns. When an aircraft does not conform, the complexity increases as more attention from ATC is required to ensure a safe separation between aircraft.Comment: 15 pages, 20 figure

    Knowledge Discovery in Spatio-Temporal Data

    Get PDF
    Tato práce se zabývá získáváním znalostí z časoprostorových dat, což je v současné době velmi rychle se vyvíjející oblast výzkumu v informačních technologiích. Nejprve popisuje obecné principy získávání znalostí, následně se po stručném úvodu do dolování v časových a prostorových datech soustředí na přehled a popis existujících metod pro dolování v časoprostorových datech. Zaměřuje se zejména na data pohybujících se objektů v podobě trajektorií s důrazem na metody pro detekci odlehlých trajektorií. V další části se práce věnuje postupu při implementaci algoritmu pro detekci odlehlých trajektorií nazvaného TOP-EYE. Za účelem otestování, ověření a možnosti použití tohoto algoritmu je navržena a realizována aplikace pro detekci odlehlých trajektorií. Algoritmus je experimentálně zhodnocen nad dvěma různými datovými sadami.This thesis deals with knowledge discovery in spatio-temporal data, which is currently a rapidly evolving area of research in information technology. First, it describes the general principles of knowledge discovery, then, after a brief introduction to mining in the temporal and spatial data, it focuses on the overview and description of existing methods for mining in spatio-temporal data. It focuses, in particular, on moving objects data in the form of trajectories with an emphasis on the methods for trajectory outlier detection. The next part of the thesis deals with the process of implementation of the trajectory outlier detection algorithm called TOP-EYE. In order to testing, validation and possibility of using this algorithm is designed and implemented an application for trajectory outlier detection. The algorithm is experimentally evaluated on two different data sets.

    Robust Photogeometric Localization over Time for Map-Centric Loop Closure

    Full text link
    Map-centric SLAM is emerging as an alternative of conventional graph-based SLAM for its accuracy and efficiency in long-term mapping problems. However, in map-centric SLAM, the process of loop closure differs from that of conventional SLAM and the result of incorrect loop closure is more destructive and is not reversible. In this paper, we present a tightly coupled photogeometric metric localization for the loop closure problem in map-centric SLAM. In particular, our method combines complementary constraints from LiDAR and camera sensors, and validates loop closure candidates with sequential observations. The proposed method provides a visual evidence-based outlier rejection where failures caused by either place recognition or localization outliers can be effectively removed. We demonstrate the proposed method is not only more accurate than the conventional global ICP methods but is also robust to incorrect initial pose guesses.Comment: To Appear in IEEE ROBOTICS AND AUTOMATION LETTERS, ACCEPTED JANUARY 201
    corecore