scholarly journals An Orlik–Raymond type classification of simply connected 6-dimensional torus manifolds with vanishing odd-degree cohomology

2016 ◽  
Vol 280 (1) ◽  
pp. 89-114 ◽  
Author(s):  
Shintarô Kuroki
Keyword(s):  
Dimensional Torus ◽  
Odd Degree ◽  
Simply Connected ◽  
Torus Manifolds ◽  
Type Classification

Automatic Grain Type Classification of Snow Micro Penetrometer Signals With Random Forests

2013 ◽  
Vol 51 (6) ◽  
pp. 3328-3335 ◽  
Author(s):  
Scott Havens ◽  
Hans-Peter Marshall ◽  
Christine Pielmeier ◽  
Kelly Elder
Keyword(s):  
Random Forests ◽  
Type Classification

scholarly journals The even Clifford structure of the fourth Severi variety

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Maurizio Parton ◽  
Paolo Piccinni
Keyword(s):  
Vector Bundle ◽  
Riemannian Manifolds ◽  
Severi Variety ◽  
Simply Connected

AbstractTheHermitian symmetric spaceM = EIII appears in the classification of complete simply connected Riemannian manifolds carrying a parallel even Clifford structure [19]. This means the existence of a real oriented Euclidean vector bundle E over it together with an algebra bundle morphism φ : Cl

scholarly journals Large-scale unsupervised clustering of Orca vocalizations: a model for describing orca communication systems

2019 ◽  
Author(s):  
Marion Poupard ◽  
Paul Best ◽  
Jan Schlüter ◽  
Helena Symonds ◽  
Paul Spong ◽  
...  
Keyword(s):  
Communication Systems ◽  
Large Scale ◽  
Pitch Contour ◽  
Call Type ◽  
Recording Station ◽  
The Face ◽  
Multichannel Recordings ◽  
Type Classification ◽  
Anthropic Pressure

Killer whales (Orcinus orca) can produce 3 types of signals: clicks, whistles and vocalizations. This study focuses on Orca vocalizations from northern Vancouver Island (Hanson Island) where the NGO Orcalab developed a multi-hydrophone recording station to study Orcas. The acoustic station is composed of 5 hydrophones and extends over 50 km 2 of ocean. Since 2015 we are continuously streaming the hydrophone signals to our laboratory in Toulon, France, yielding nearly 50 TB of synchronous multichannel recordings. In previous work, we trained a Convolutional Neural Network (CNN) to detect Orca vocalizations, using transfer learning from a bird activity dataset. Here, for each detected vocalization, we estimate the pitch contour (fundamental frequency). Finally, we cluster vocalizations by features describing the pitch contour. While preliminary, our results demonstrate a possible route towards automatic Orca call type classification. Furthermore, they can be linked to the presence of particular Orca pods in the area according to the classification of their call types. A large-scale call type classification would allow new insights on phonotactics and ethoacoustics of endangered Orca populations in the face of increasing anthropic pressure.

Surgery Theory and the Classification of Closed, Simply Connected 4-manifolds

2021 ◽  
pp. 331-352
Author(s):  
Patrick Orson ◽  
Mark Powell ◽  
Arunima Ray
Keyword(s):  
Embedding Theorem ◽  
Surgery Theory ◽  
Simply Connected

Surgery theory and the classification of simply connected 4-manifolds comprise two key consequences of the disc embedding theorem. The chapter begins with an introduction to surgery theory from the perspective of 4-manifolds. In particular, the terms and maps in the surgery sequence are defined, and an explanation is given as to how the sphere embedding theorem, with the added ingredient of topological transversality, can be used to define the maps in the surgery sequence and show that it is exact. The surgery sequence is applied to classify simply connected closed 4-manifolds up to homeomorphism. The chapter closes with a survey of related classification results.

The Development of Topological 4-manifold Theory

2021 ◽  
pp. 295-330
Author(s):  
Mark Powell ◽  
Arunima Ray
Keyword(s):  
Euclidean Space ◽  
Dimensional Euclidean Space ◽  
Smooth Structures ◽  
Normal Bundles ◽  
Exotic Smooth Structures ◽  
Poincare Conjecture ◽  
Manifold Theory ◽  
Simply Connected

The development of topological 4-manifold theory is described in the form of a flowchart showing the interdependence among many key statements in the theory. In particular, the flowchart demonstrates how the theory crucially relies on the constructions in this book, what goes into the work of Quinn on smoothing, normal bundles, and transversality, and what is needed to deduce the famous consequences, such as the classification of closed, simply connected, topological 4-manifolds, the category preserving Poincaré conjecture, and the existence of exotic smooth structures on 4-dimensional Euclidean space. Precise statements of the results, brief indications of some proofs, and extensive references are provided.

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