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arXiv research

A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,742 papers · 148 categories

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35810 · May 201919922001200920172026
48 results for Checkerboard artifacts

Proposes a fixed smooth convolutional layer to reduce checkerboard artifacts in CNNs.

problem Checkerboard artifacts in CNNs during upsampling and strided convolution.
method Fixed convolutional layer with adjustable smoothness, applied to four CNNs and GANs.
result Significantly improves classification performance and image generation quality.

Geometric duality connects graph isomorphism and knot equivalence.

problem Understanding the equivalence of graph isomorphism and knot equivalence.
method Observation of geometric duality in planar graphs and links.
result The equivalence relation defined by isomorphisms of checkerboard graphs is the same as 2-isomorphisms of checkerboard graphs.

Associated to every state surface for a knot or link is a state graph, which embeds as a spine of the state surface. A state graph can be decomposed along cut-vertices into graphs with induced planar embeddings. Associated with each such planar graph is a checkerboard surface, and each state surface is a fiber if and o…

2019-02-05abs ↗pdf ↗

Checkerboard surfaces in alternating link complements are used frequently to determine information about the link. However, when many crossings are added to a single twist region of a link diagram, the geometry of the link complement stabilizes (approaches a geometric limit), but a corresponding checkerboard surface in…

2014-10-23abs ↗pdf ↗

We define an equivalence relation on graphs with signed edges, such that the associated adjacency matrices of two equivalent graphs are congruent over Z\mathbb{Z}. We show that signed graphs whose eigenvalues are larger than 2-2 are equivalent to one of the simply laced Dynkin diagrams: AnA_{n}, DnD_{n}, E6E_{6}, $E_…

2019-07-21abs ↗pdf ↗

The notion of chckerboard colorability for virtual links and abstract links is introduced. We study the Jones polynomials of virtual links and abstruct links. It is proved that a certain property of the Jones polynomials of classical links is valid for virtual links which admit checkerboard colorings.

2000-08-10abs ↗pdf ↗

We associate an open book with any connected plane checkerboard graph, thus providing a common extension of the classes of prime positive braid links and positive tree-like Hopf plumbings. As an application, we prove that the link type of a prime positive braid closure is determined by the linking graph associated with…

2017-06-28abs ↗pdf ↗

The paper explores discrete isothermic nets using checkerboard patterns in quadrilateral nets.

problem Defining and understanding discrete isothermic nets in quadrilateral nets.
method Using checkerboard patterns and discrete differential geometry to define and analyze isothermic nets.
result The class of isothermic nets is invariant under dualization and Moebius transformations.

The paper studies right-angled links on higher genus surfaces.

problem Classifying and understanding right-angled links on surfaces of higher genus.
method Defining and proving equivalence of properties for RGCR links, using diagram restrictions and polygonal checkerboard surfaces.
result Classification of RGCR links and bounds on their number for a given genus.

We present a procedure which allows one to integrate explicitly the class of checkerboard IC-nets which has recently been introduced as a generalisation of incircular (IC) nets. The latter class of privileged congruences of lines in the plane is known to admit a great variety of geometric properties which are also pres…

2018-08-22abs ↗pdf ↗

Determinant modulo 8 classifies virtual knots based on polynomial coefficients.

problem Classifying virtual knots using determinant modulo 8.
method Introduced a determinant for checkerboard colorable virtual knots and proved its classification by the coefficient of z2z^2 in the ascending polynomial.
result Determinant modulo 8 classifies virtual knots based on polynomial coefficients.

We consider congruences of straight lines in a plane with the combinatorics of the square grid, with all elementary quadrilaterals possessing an incircle. It is shown that all the vertices of such nets (we call them incircular or IC-nets) lie on confocal conics. Our main new results are on checkerboard IC-nets in the p…

2016-02-15abs ↗pdf ↗

Extends Gordon-Litherland pairing to links in thickened surfaces, defining new invariants.

problem Defining invariants for links in thickened surfaces.
method Extending Gordon-Litherland pairing, defining new invariants based on spanning surfaces.
result Invariants depend only on SS^*-equivalence class of spanning surfaces and give well-defined invariants of virtual links.

Essential surfaces in link diagrams on surfaces are crucial for understanding link properties.

problem Understanding the essentiality of surfaces in link diagrams on surfaces.
method Proving checkerboard surfaces are π1-essential and contain no essential closed curves that are ∂-parallel.
result Checkerboard surfaces of alternating link diagrams are π1-essential and contain no essential closed curves that are ∂-parallel.

Study examines how image artifacts impact polyp detection and proposes methods to mitigate their effects.

problem Impact of image artifacts on automated polyp detection accuracy.
method Systematic analysis of six artifact classes, investigation of learning without forgetting framework.
result Artifacts can either benefit or harm polyp detection; learning without forgetting can mitigate some harmful effects.

New method corrects motion artifacts in MR images without paired data.

problem Lack of paired data for supervised training in deep learning for MR motion correction.
method Outlier-rejecting bootstrap subsampling and aggregation, using optimal transport cycleGAN.
result Outperforms existing deep learning methods in correcting motion artifacts from TSM.

Electroencephalograms (EEG) are often contaminated by artifacts which make interpreting them more challenging for clinicians. Hence, automated artifact recognition systems have the potential to aid the clinical workflow. In this abstract, we share the first results on applying various machine learning algorithms to the…

2019-03-19abs ↗pdf ↗

It is shown that there exist alternating non-Montesinos knots whose essential spanning surfaces with maximal and minimal boundary slopes are not realised by the checkerboard surfaces coming from a reduced alternating planar diagram.

2014-01-13abs ↗pdf ↗

This monograph derives direct and concrete relations between colored Jones polynomials and the topology of incompressible spanning surfaces in knot and link complements. Under mild diagrammatic hypotheses that arise naturally in the study of knot polynomial invariants (A- or B-adequacy), we prove that the growth of the…

2011-08-16abs ↗pdf ↗

In this paper we review the definitions of homogeneous and alternative links. We also give two new characterizations of an alternative link diagram, one within the context of the enhanced checkerboard graph and another from the labeled Seifert graph.

2014-10-25abs ↗pdf ↗

Study geodesic X-ray transform and streaking artifacts on simple surfaces or spaces of constant curvature.

problem Streaking artifacts in CT images due to metal regions.
method Geodesic X-ray transform on nontrapping compact Riemannian manifolds with strictly convex boundaries.
result Streaking artifacts result from conormal singularities along common tangent geodesics.

In this paper, we study the Khovanov homology of an alternating virtual link LL and show that it is supported on g+2g+2 diagonal lines, where gg equals the virtual genus of LL. Specifically, we show that Khi,j(L)Kh^{i,j}(L) is supported on the lines j=2iσξ+2k1j=2i-σ_ξ+2k-1 for 0kg+10\leq k\leq g+1 where σξ(L)+2g=σξ(L)σ_{ξ^*}(L)+2g= σ_ξ(L) are th…

2019-04-28abs ↗pdf ↗

Paper introduces adversarial lossy compression for video artifacts reduction.

problem Unpleasant reconstruction artifacts in standard video coding schemes at low bit-rates.
method Adversarial lossy video compression model minimizing an adversarial distortion objective.
result Reduction of perceptual artifacts and detail reconstruction under extreme compression.

A new unsupervised method removes CT metal artifacts using beta-CycleGAN and attention.

problem Metal artifact reduction in computed tomography (CT) images.
method Unsupervised learning using a beta-CycleGAN architecture with attention mechanism.
result Improved metal artifact removal that preserves image details.

Improved linear upper bound for ribbonlength of knots.

problem Estimating the ribbonlength of knots and links.
method Using four-page open book decompositions and spanning trees of checkerboard graphs, constructing a four-page presentation with at most 2c(K) arcs.
result Proved that ribbonlength is bounded above by the four-page index, leading to the linear bound Rib(K) ≤ 2c(K).

Paper explores unsupervised learning for ultrasound image artifact removal.

problem Improving visual quality of ultrasound images from various artifacts.
method Inspired by optimal transport cycleGAN, unsupervised deep learning for artifact removal.
result Unsupervised learning method provides comparable results to supervised learning.

A group-theoretical method, via Wada's representations, is presented to distinguish Kishino's virtual knot from the unknot. Biquandles are constructed for any group using Wada's braid group representations. Cocycle invariants for these biquandles are studied. These invariants are applied to show the non-existence of Al…

2007-03-20abs ↗pdf ↗

Interpretation of electroencephalogram (EEG) signals can be complicated by obfuscating artifacts. Artifact detection plays an important role in the observation and analysis of EEG signals. Spatial information contained in the placement of the electrodes can be exploited to accurately detect artifacts. However, when few…

2018-01-03abs ↗pdf ↗

Generative model predicts menstrual cycle lengths accounting for self-tracking artifacts.

problem Uncertainty in self-tracked health data due to user adherence.
method Hierarchical, generative model using machine learning.
result Model yields state-of-the-art performance in predicting menstrual cycle lengths.

Estimates support in distributions with sampling artifacts and errors.

problem Support estimation in the presence of sampling artifacts and errors.
method Regularized weighted Chebyshev approximations with Touchard polynomials, discretized semi-infinte programming.
result Significant improvements over noiseless support estimation methods.

Deconvolutional layers have been widely used in a variety of deep models for up-sampling, including encoder-decoder networks for semantic segmentation and deep generative models for unsupervised learning. One of the key limitations of deconvolutional operations is that they result in the so-called checkerboard problem.…

2017-05-18abs ↗pdf ↗