2,172 research outputs found
A Survey on Deep Learning in Medical Image Analysis
Deep learning algorithms, in particular convolutional networks, have rapidly
become a methodology of choice for analyzing medical images. This paper reviews
the major deep learning concepts pertinent to medical image analysis and
summarizes over 300 contributions to the field, most of which appeared in the
last year. We survey the use of deep learning for image classification, object
detection, segmentation, registration, and other tasks and provide concise
overviews of studies per application area. Open challenges and directions for
future research are discussed.Comment: Revised survey includes expanded discussion section and reworked
introductory section on common deep architectures. Added missed papers from
before Feb 1st 201
The Life and Death of Music as East Asian Intangible Cultural Heritage
An exploration of the policies for preserving and promoting music as Intangible Cultural Heritage in Korea and Japan, looking at the emerging distinction between preserved forms and commercial/professional derivatives
Mechanising syntax with binders in Coq
Mechanising binders in general-purpose proof assistants such as Coq is cumbersome and difficult. Yet binders, substitutions, and instantiation of terms with substitutions are a critical ingredient of many programming languages. Any practicable mechanisation of the meta-theory of the latter hence requires a lean formalisation of the former. We investigate the topic from three angles: First, we realise formal systems with binders based on both pure and scoped de Bruijn algebras together with basic syntactic rewriting lemmas and automation. We automate this process in a compiler called Autosubst; our final tool supports many-sorted, variadic, and modular syntax. Second, we justify our choice of realisation and mechanise a proof of convergence of the sigma calculus, a calculus of explicit substitutions that is complete for equality of the de Bruijn algebra corresponding to the lambda calculus. Third, to demonstrate the practical usefulness of our approach, we provide concise, transparent, and accessible mechanised proofs for a variety of case studies refined to de Bruijn substitutions.Die Mechanisierung von Bindern in universellen Beweisassistenten wie Coq ist arbeitsaufwändig und schwierig. Binder, Substitutionen und die Instantiierung von Substitutionen sind jedoch kritischer Bestandteil
vieler Programmiersprachen. Deshalb setzt eine praktikable Mechanisierung der Metatheorie von Programmiersprachen eine elegante Formalisierung von Bindern voraus. Wir nähern uns dem Thema aus drei Richtungen an:
Zuerst realisieren wir formale Systeme mit Bindern mit Hilfe von reinen und indizierten de Bruijn Algebren, zusammen mit grundlegenden syntaktischen Gleichungen und Automatisierung. Wir automatisieren diesen Prozess in
einem Kompilierer namens Autosubst. Unser finaler Kompilierer unterstützt Sortenlogik, variadische Syntax und modulare Syntax. Zweitens rechtfertigen wir unsere Repräsentation und mechanisieren einen Beweis der Konvergenz
des SP-Kalküls, einem Kalkül expliziter Substitutionen der bezüglich der Gleichheit der puren de Bruijn Algebra des -Kalküls vollständig ist. Drittens entwickeln wir kurze, transparente und leicht zugängliche mechanisierte
Beweise für diverse Fallstudien, die wir an de Bruijn Substitutionen angepasst haben. Wir weisen so die praktische Anwendbarkeit unseres Ansatzes nach
The Leptoquark Hunter's Guide: Pair Production
Leptoquarks occur in many new physics scenarios and could be the next big
discovery at the LHC. The purpose of this paper is to point out that a
model-independent search strategy covering all possible leptoquarks is possible
and has not yet been fully exploited. To be systematic we organize the possible
leptoquark final states according to a leptoquark matrix with entries
corresponding to nine experimentally distinguishable leptoquark decays: any of
{light-jet, b-jet, top} with any of {neutrino, , }. The 9
possibilities can be explored in a largely model-independent fashion with
pair-production of leptoquarks at the LHC. We review the status of experimental
searches for the 9 components of the leptoquark matrix, pointing out which 3
have not been adequately covered. We plead that experimenters publish bounds on
leptoquark cross sections as functions of mass for as wide a range of
leptoquark masses as possible. Such bounds are essential for reliable recasts
to general leptoquark models. To demonstrate the utility of the leptoquark
matrix approach we collect and summarize searches with the same final states as
leptoquark pair production and use them to derive bounds on a complete set of
Minimal Leptoquark models which span all possible flavor and gauge
representations for scalar and vector leptoquarks.Comment: 19 pages + references and appendices, 18 figures, 15 tables. Added
references, fixed typo
HERA-data in the light of small x evolution with state of the art NLO input
Both total and diffractive cross sections from HERA are successfully
confronted with JIMWLK evolution equations in the asymptotic pseudo-scaling
region. We present a consistent, simultaneous description of both types of
cross sections that includes NLO corrections in the form of running coupling
and energy conservation corrections. The inclusion of energy conservation
corrections allows to match all available data with x below .02 i.e. up to Q^2
of 1200 GeV^2. We discuss the effects of quark masses including charm, contrast
asymptotic and pre-asymptotic fit strategies, and survey non-perturbative
uncertainties related to impact parameter dependence.Comment: 61 pages, 27 figure
The International Deep Planet Survey I. The frequency of wide-orbit massive planets around A-stars
Breakthrough direct detections of planetary companions orbiting A-type stars
confirm the existence of massive planets at relatively large separations, but
dedicated surveys are required to estimate the frequency of similar planetary
systems. To measure the first estimation of the giant exoplanetary systems
frequency at large orbital separation around A-stars, we have conducted a
deep-imaging survey of young (8-400 Myr), nearby (19-84 pc) A- and F-stars to
search for substellar companions in the 10-300 AU range. The sample of 42 stars
combines all A-stars observed in previous AO planet search surveys reported in
the literature with new AO observations from VLT/NaCo and Gemini/NIRI. It
represents an initial subset of the International Deep Planet Survey (IDPS)
sample of stars covering M- to B-stars. The data were obtained with
diffraction-limited observations in H- and Ks-band combined with angular
differential imaging to suppress the speckle noise of the central stars,
resulting in typical 5-sigma detection limits in magnitude difference of 12 mag
at 1", 14 mag at 2" and 16 mag at 5" which is sufficient to detect massive
planets. A detailed statistical analysis of the survey results is performed
using Monte Carlo simulations. Considering the planet detections, we estimate
the fraction of A-stars having at least one massive planet (3-14 MJup) in the
range 5-320 AU to be inside 5.9-18.8% at 68% confidence, assuming a flat
distribution for the mass of the planets. By comparison, the brown dwarf (15-75
MJup) frequency for the sample is 2.0-8.9% at 68% confidence in the range 5-320
AU. Assuming power law distributions for the mass and semimajor axis of the
planet population, the AO data are consistent with a declining number of
massive planets with increasing orbital radius which is distinct from the
rising slope inferred from radial velocity (RV) surveys around evolved A-stars.Comment: 20 pages, 10 figures, 7 tables. Accepted for publication in A&
Traffic Scene Perception for Automated Driving with Top-View Grid Maps
Ein automatisiertes Fahrzeug muss sichere, sinnvolle und schnelle Entscheidungen auf Basis seiner Umgebung treffen.
Dies benötigt ein genaues und recheneffizientes Modell der Verkehrsumgebung.
Mit diesem Umfeldmodell sollen Messungen verschiedener Sensoren fusioniert, gefiltert und nachfolgenden Teilsysteme als kompakte, aber aussagekräftige Information bereitgestellt werden.
Diese Arbeit befasst sich mit der Modellierung der Verkehrsszene auf Basis von Top-View Grid Maps.
Im Vergleich zu anderen Umfeldmodellen ermöglichen sie eine frühe Fusion von Distanzmessungen aus verschiedenen Quellen mit geringem Rechenaufwand sowie eine explizite Modellierung von Freiraum.
Nach der Vorstellung eines Verfahrens zur Bodenoberflächenschätzung, das die Grundlage der Top-View Modellierung darstellt, werden Methoden zur Belegungs- und Elevationskartierung für Grid Maps auf Basis von mehreren, verrauschten, teilweise widersprüchlichen oder fehlenden Distanzmessungen behandelt.
Auf der resultierenden, sensorunabhängigen Repräsentation werden anschließend Modelle zur Detektion von Verkehrsteilnehmern sowie zur Schätzung von Szenenfluss, Odometrie und Tracking-Merkmalen untersucht.
Untersuchungen auf öffentlich verfügbaren Datensätzen und einem Realfahrzeug zeigen, dass Top-View Grid Maps durch on-board LiDAR Sensorik geschätzt und verlässlich sicherheitskritische Umgebungsinformationen wie Beobachtbarkeit und Befahrbarkeit abgeleitet werden können.
Schließlich werden Verkehrsteilnehmer als orientierte Bounding Boxen mit semantischen Klassen, Geschwindigkeiten und Tracking-Merkmalen aus einem gemeinsamen Modell zur Objektdetektion und Flussschätzung auf Basis der Top-View Grid Maps bestimmt
Subleading Regge limit from a soft anomalous dimension
Wilson lines capture important features of scattering amplitudes, for example
soft effects relevant for infrared divergences, and the Regge limit. Beyond the
leading power approximation, corrections to the eikonal picture have to be
taken into account. In this paper, we study such corrections in a model of
massive scattering amplitudes in N = 4 super Yang-Mills, in the planar limit,
where the mass is generated through a Higgs mechanism. Using known three-loop
analytic expressions for the scattering amplitude, we find that the first power
suppressed term has a very simple form, equal to a single power law. We propose
that its exponent is governed by the anomalous dimension of a Wilson loop with
a scalar inserted at the cusp, and we provide perturbative evidence for this
proposal. We also analyze other limits of the amplitude and conjecture an exact
formula for a total cross-section at high energies.Comment: 19 pages, several appendices, many figure
- …