213 research outputs found

    Advances and Applications of DSmT for Information Fusion. Collected Works, Volume 5

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    This fifth volume on Advances and Applications of DSmT for Information Fusion collects theoretical and applied contributions of researchers working in different fields of applications and in mathematics, and is available in open-access. The collected contributions of this volume have either been published or presented after disseminating the fourth volume in 2015 in international conferences, seminars, workshops and journals, or they are new. The contributions of each part of this volume are chronologically ordered. First Part of this book presents some theoretical advances on DSmT, dealing mainly with modified Proportional Conflict Redistribution Rules (PCR) of combination with degree of intersection, coarsening techniques, interval calculus for PCR thanks to set inversion via interval analysis (SIVIA), rough set classifiers, canonical decomposition of dichotomous belief functions, fast PCR fusion, fast inter-criteria analysis with PCR, and improved PCR5 and PCR6 rules preserving the (quasi-)neutrality of (quasi-)vacuous belief assignment in the fusion of sources of evidence with their Matlab codes. Because more applications of DSmT have emerged in the past years since the apparition of the fourth book of DSmT in 2015, the second part of this volume is about selected applications of DSmT mainly in building change detection, object recognition, quality of data association in tracking, perception in robotics, risk assessment for torrent protection and multi-criteria decision-making, multi-modal image fusion, coarsening techniques, recommender system, levee characterization and assessment, human heading perception, trust assessment, robotics, biometrics, failure detection, GPS systems, inter-criteria analysis, group decision, human activity recognition, storm prediction, data association for autonomous vehicles, identification of maritime vessels, fusion of support vector machines (SVM), Silx-Furtif RUST code library for information fusion including PCR rules, and network for ship classification. Finally, the third part presents interesting contributions related to belief functions in general published or presented along the years since 2015. These contributions are related with decision-making under uncertainty, belief approximations, probability transformations, new distances between belief functions, non-classical multi-criteria decision-making problems with belief functions, generalization of Bayes theorem, image processing, data association, entropy and cross-entropy measures, fuzzy evidence numbers, negator of belief mass, human activity recognition, information fusion for breast cancer therapy, imbalanced data classification, and hybrid techniques mixing deep learning with belief functions as well

    Atom zu Photon Quantenzustandstransfer und Teleportation - Experimente im Labor und über eine urbane Faser

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    Single photon-pair sources are essential for future quantum networks. To be used effectively, the following requirements are essential: high photon rates, high-fidelity entanglement and light-matter interfaces to quantum memories. This work describes the setup and characterisation of a single photon pair-source based on cavity-enhanced spontaneous parametric down conversion resonant to the D5/2 to P3/2 transition of a single 40Ca+ quantum memory fulfilling the upper requirements. The main goal is the realisation of quantum state teleportation over a metropolitan fibre using the source as a resource of entanglement. Our experiments demonstrate the preservation of high-fidelity entanglement during conversion to the low-loss, low-dispersion telecom wavelength range at 1550 nm and fibre transmission over a metropolitan fibre and up to 40 km of fibre spool, including back-conversion to the memory wavelength. Further experiments show the excellent performance of our network protocols in transferring photon-photon entanglement to ion-photon entanglement and teleporting a spin qubit from the ion onto a polarisation qubit of a photon. Both protocols are based on the heralded absorption of one photon from a pair by the ion. The interface operations are also demonstrated with quantum frequency conversion and a metropolitan fibre of 14 km length.Einzelphotonen-Paarquellen sind für künftige Quantennetze unverzichtbar. Um effektiv nutzbar zu sein, müssen folgende Anforderungen erfüllt sein: hohe Photonenraten, hohe Verschränkungsgüte und Licht-Materie-Schnittstellen zu Quantenspeichern. Diese Arbeit beschreibt den Aufbau und die Charakterisierung einer Einzelphotonen-Paarquelle auf der Basis resonatorverstärkter spontaner parametrischer Abwärtskonversion, die mit dem D5/2 zu P3/2-Übergang eines einzelnen 40Ca+-Quantenspeichers resonant ist und die oberen Anforderungen erfüllt. Das Hauptziel ist die Realisierung einer Quantenzustands-Teleportation über eine städtische Faser unter Verwendung der Quelle als Ressource der Verschränkung. Unsere Experimente demonstrieren die Erhaltung der Verschränkung mit hoher Güte während der Konversion in den verlust- und streuungsarmen Wellenlängenbereich bei 1550 nm und der Übertragung über eine städtische Faser und bis zu 40 km Faserspule, einschließlich der Rückkonversion zur Speicherwellenlänge. Weitere Experimente zeigen die hervorragende Leistung unserer Netzwerkprotokolle bei der Übertragung von Photonen-Photonen-Verschränkung auf Ionen-Photonen-Verschränkung und bei Teleportation eines Spin-Qubits vom Ion auf ein Polarisations-Qubit eines Photons. Beide Protokolle beruhen auf der angekündigten Absorption eines Photons aus einem Paar durch das Ion. Die Schnittstellenoperationen werden auch mit Quantenfrequenzkonversion und einer 14 km langen städtischen Faser demonstriert

    Undergraduate and Graduate Course Descriptions, 2023 Spring

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    Wright State University undergraduate and graduate course descriptions from Spring 2023

    Localization in urban environments. A hybrid interval-probabilistic method

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    Ensuring safety has become a paramount concern with the increasing autonomy of vehicles and the advent of autonomous driving. One of the most fundamental tasks of increased autonomy is localization, which is essential for safe operation. To quantify safety requirements, the concept of integrity has been introduced in aviation, based on the ability of the system to provide timely and correct alerts when the safe operation of the systems can no longer be guaranteed. Therefore, it is necessary to assess the localization's uncertainty to determine the system's operability. In the literature, probability and set-membership theory are two predominant approaches that provide mathematical tools to assess uncertainty. Probabilistic approaches often provide accurate point-valued results but tend to underestimate the uncertainty. Set-membership approaches reliably estimate the uncertainty but can be overly pessimistic, producing inappropriately large uncertainties and no point-valued results. While underestimating the uncertainty can lead to misleading information and dangerous system failure without warnings, overly pessimistic uncertainty estimates render the system inoperative for practical purposes as warnings are fired more often. This doctoral thesis aims to study the symbiotic relationship between set-membership-based and probabilistic localization approaches and combine them into a unified hybrid localization approach. This approach enables safe operation while not being overly pessimistic regarding the uncertainty estimation. In the scope of this work, a novel Hybrid Probabilistic- and Set-Membership-based Coarse and Refined (HyPaSCoRe) Localization method is introduced. This method localizes a robot in a building map in real-time and considers two types of hybridizations. On the one hand, set-membership approaches are used to robustify and control probabilistic approaches. On the other hand, probabilistic approaches are used to reduce the pessimism of set-membership approaches by augmenting them with further probabilistic constraints. The method consists of three modules - visual odometry, coarse localization, and refined localization. The HyPaSCoRe Localization uses a stereo camera system, a LiDAR sensor, and GNSS data, focusing on localization in urban canyons where GNSS data can be inaccurate. The visual odometry module computes the relative motion of the vehicle. In contrast, the coarse localization module uses set-membership approaches to narrow down the feasible set of poses and provides the set of most likely poses inside the feasible set using a probabilistic approach. The refined localization module further refines the coarse localization result by reducing the pessimism of the uncertainty estimate by incorporating probabilistic constraints into the set-membership approach. The experimental evaluation of the HyPaSCoRe shows that it maintains the integrity of the uncertainty estimation while providing accurate, most likely point-valued solutions in real-time. Introducing this new hybrid localization approach contributes to developing safe and reliable algorithms in the context of autonomous driving

    The Fifteenth Marcel Grossmann Meeting

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    The three volumes of the proceedings of MG15 give a broad view of all aspects of gravitational physics and astrophysics, from mathematical issues to recent observations and experiments. The scientific program of the meeting included 40 morning plenary talks over 6 days, 5 evening popular talks and nearly 100 parallel sessions on 71 topics spread over 4 afternoons. These proceedings are a representative sample of the very many oral and poster presentations made at the meeting.Part A contains plenary and review articles and the contributions from some parallel sessions, while Parts B and C consist of those from the remaining parallel sessions. The contents range from the mathematical foundations of classical and quantum gravitational theories including recent developments in string theory, to precision tests of general relativity including progress towards the detection of gravitational waves, and from supernova cosmology to relativistic astrophysics, including topics such as gamma ray bursts, black hole physics both in our galaxy and in active galactic nuclei in other galaxies, and neutron star, pulsar and white dwarf astrophysics. Parallel sessions touch on dark matter, neutrinos, X-ray sources, astrophysical black holes, neutron stars, white dwarfs, binary systems, radiative transfer, accretion disks, quasars, gamma ray bursts, supernovas, alternative gravitational theories, perturbations of collapsed objects, analog models, black hole thermodynamics, numerical relativity, gravitational lensing, large scale structure, observational cosmology, early universe models and cosmic microwave background anisotropies, inhomogeneous cosmology, inflation, global structure, singularities, chaos, Einstein-Maxwell systems, wormholes, exact solutions of Einstein's equations, gravitational waves, gravitational wave detectors and data analysis, precision gravitational measurements, quantum gravity and loop quantum gravity, quantum cosmology, strings and branes, self-gravitating systems, gamma ray astronomy, cosmic rays and the history of general relativity

    Robust artificial clock transition by continuous dynamical decoupling in multi-ion calcium crystals

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    Optical atomic clocks reach astonishingly low frequency uncertainties. Therefore, they are a valuable tool for applications even beside time determination. Predicted extensions of the standard model of particle physics can be tested using these clocks. For this reason, they can help to uncover unresolved discrepancies between these models and the observed universe. A low frequency uncertainty also enables height measurements according to general relativity. Clock comparisons over long distances might be used to refine geodetic models of the earth’s gravitational potential. A variety of atomic species and techniques are in competition for realizing the most accurate clock. The aluminium single ion clock is, at the moment, the most accurate clock. But it is impeded by long averaging times due to the quantum projection noise limit. For some of the aforementioned applications, this is a serious drawback. Larger ion crystals offer an increased signal-to-noise ratio, but maintaining their frequency accuracy is demanding, as the strong confinement potentials shift the atomic resonance. This thesis reports on the experimental realization of a continuous dynamical decoupling technique. Designed coupling of Zeeman sub-levels by radio-frequency fields is used to mitigate major frequency shifts in 40Ca+ crystals. The obtained artificial clock transition has the potential to compete with more promising clock transitions of different atomic species regarding its low sensitivity to magnetic field fluctuations as well as suppressed quadrupole and tensorial ac-Stark shifts. Long coherence times in multi-ion 40Ca+ crystals are obtained for the artificial transition. Thus, the system’s potential for a low statistical uncertainty makes it promising as a replacement for a lattice clock in a compound clock or for applications where frequency differences must be determined on a short timescale.Optische Atomuhren erreichen außergewöhnlich niedrige Frequenzunsicherheiten. Daher sind sie selbst für Anwendungen neben der Zeitbestimmung ein nützliches Werkzeug. Erweiterungen des Standardmodells der Teilchenphysik können durch sie getestet werden und somit können sie helfen, ungelöste Diskrepanzen dieser Modelle mit dem beobachteten Universum aufzudecken. Außerdem werden Höhenmessungen nach Vorhersage der allgemeinen Relativitätstheorie ermöglicht. Uhrenvergleiche über lange Distanzen können verwendet werden, um geodätische Modelle des Gravitationspotentials der Erde zu verbessern. Viele Atomarten und Techniken konkurrieren um die Realisierung der genauesten Uhr. Derzeit hat die Aluminium- Einzelionenuhr die höchste Genauigkeit. Aufgrund ihrer Limitierung durch Quanten-Projektions-Rauschen sind lange Mittelungszeiten erforderlich. Dies ist ein großer Nachteil für einige der oben genannten Anwendungen. Mehrionenkristalle bieten ein größeres Signal-zu-Rauschverhältnis, die Erhaltung ihrer Frequenzgenauigkeit wird jedoch durch die starken Einschlusspotentiale erschwert, welche die atomare Resonanz verschieben. Diese Arbeit beinhaltet die experimentelle Realisierung einer kontinuierlich dynamischen Entkopplungstechnik. Maßgeschneiderte Radiofrequenzfelder werden zur Kopplung von Zeeman- Zuständen genutzt, um einige Frequenzverschiebungen in 40Ca+ Kristallen abzuschwächen. Der künstlich erzeugte Uhrenübergang hat das Potenzial, zu vielversprechenderen Übergängen anderer Atomarten aufzuschließen. Dies gilt in Hinblick auf seine geringe Empfindlichkeit gegenüber Magnetfeldfluktuationen, sowie der unterdrückten Quadrupol- und tensoriellen,dynamischen Stark-Verschiebung. Für den künstlichen Übergang werden lange Kohärenzzeiten in Mehrionen 40Ca+ Kristallen erreicht. Der Austausch von Gitteruhren in einer Hybriduhr durch große Ionenkristalle wird aufgrund der langen Kohärenzzeiten ihres künstlichen Übergangs denkbar. Außerdem ist der künstliche Übergang für Anwendungen interessant, bei denen Frequenzunterschiede auf einer kurzen Zeitskala bestimmt werden müssen

    ATHENA Research Book, Volume 2

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    ATHENA European University is an association of nine higher education institutions with the mission of promoting excellence in research and innovation by enabling international cooperation. The acronym ATHENA stands for Association of Advanced Technologies in Higher Education. Partner institutions are from France, Germany, Greece, Italy, Lithuania, Portugal and Slovenia: University of Orléans, University of Siegen, Hellenic Mediterranean University, Niccolò Cusano University, Vilnius Gediminas Technical University, Polytechnic Institute of Porto and University of Maribor. In 2022, two institutions joined the alliance: the Maria Curie-Skłodowska University from Poland and the University of Vigo from Spain. Also in 2022, an institution from Austria joined the alliance as an associate member: Carinthia University of Applied Sciences. This research book presents a selection of the research activities of ATHENA University's partners. It contains an overview of the research activities of individual members, a selection of the most important bibliographic works of members, peer-reviewed student theses, a descriptive list of ATHENA lectures and reports from individual working sections of the ATHENA project. The ATHENA Research Book provides a platform that encourages collaborative and interdisciplinary research projects by advanced and early career researchers

    An aluminum optical clock setup and its evaluation using Ca+

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    This thesis reports about the progress of the aluminum ion clock that is set up at the German National Metrological Institute, Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig. All known relevant systematic frequency shifts are discussed. The systematic shifts were measured on the co-trapped logic ion 40Ca+, which is advantageous due to its higher sensitivity to external fields compared to 27Al+. The observation of the clock transition of 27Al+ and an analysis of the detection error is described.DFG/DQ-mat/Project-ID 274200144 – SFB 1227/E
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