4,160 research outputs found
Spatially and polarization resolved plasmon mediated transmission through continuous metal films
The experimental demonstration and characterization is made of the
plasmon-mediated resonant transmission through an embedded undulated continuous
thin metal film under normal incidence. 1D undulations are shown to enable a
spatially resolved polarisation filtering whereas 2D undulations lead to
spatially resolved, polarization independent transmission. Whereas the needed
submicron microstructure lends itself in principle to CD-like low-cost mass
replication by means of injection moulding and embossing, the present paper
demonstrates the expected transmission effects on experimental models based on
metal-coated photoresist gratings. The spectral and angular dependence in the
neighbourhood of resonance are investigated and the question of the excess
losses exhibited by surface plasmons is discusse
Quantum Gravity as Topological Quantum Field Theory
The physics of quantum gravity is discussed within the framework of
topological quantum field theory. Some of the principles are illustrated with
examples taken from theories in which space-time is three dimensional.Comment: 23 pages, amstex, JMP special issue (deadline permitting). (Text not
changed
Satisfiability for two-variable logic with two successor relations on finite linear orders
We study the finitary satisfiability problem for first order logic with two
variables and two binary relations, corresponding to the induced successor
relations of two finite linear orders. We show that the problem is decidable in
NEXPTIME
Learning Points and Routes to Recommend Trajectories
The problem of recommending tours to travellers is an important and broadly
studied area. Suggested solutions include various approaches of
points-of-interest (POI) recommendation and route planning. We consider the
task of recommending a sequence of POIs, that simultaneously uses information
about POIs and routes. Our approach unifies the treatment of various sources of
information by representing them as features in machine learning algorithms,
enabling us to learn from past behaviour. Information about POIs are used to
learn a POI ranking model that accounts for the start and end points of tours.
Data about previous trajectories are used for learning transition patterns
between POIs that enable us to recommend probable routes. In addition, a
probabilistic model is proposed to combine the results of POI ranking and the
POI to POI transitions. We propose a new F score on pairs of POIs that
capture the order of visits. Empirical results show that our approach improves
on recent methods, and demonstrate that combining points and routes enables
better trajectory recommendations
Deep Unsupervised Similarity Learning using Partially Ordered Sets
Unsupervised learning of visual similarities is of paramount importance to
computer vision, particularly due to lacking training data for fine-grained
similarities. Deep learning of similarities is often based on relationships
between pairs or triplets of samples. Many of these relations are unreliable
and mutually contradicting, implying inconsistencies when trained without
supervision information that relates different tuples or triplets to each
other. To overcome this problem, we use local estimates of reliable
(dis-)similarities to initially group samples into compact surrogate classes
and use local partial orders of samples to classes to link classes to each
other. Similarity learning is then formulated as a partial ordering task with
soft correspondences of all samples to classes. Adopting a strategy of
self-supervision, a CNN is trained to optimally represent samples in a mutually
consistent manner while updating the classes. The similarity learning and
grouping procedure are integrated in a single model and optimized jointly. The
proposed unsupervised approach shows competitive performance on detailed pose
estimation and object classification.Comment: Accepted for publication at IEEE Computer Vision and Pattern
Recognition 201
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