Search Results for author: Johan Karlsson

Found 13 papers, 4 papers with code

A cutting plane algorithm for globally solving low dimensional k-means clustering problems

no code implementations21 Feb 2024 Martin Ryner, Jan Kronqvist, Johan Karlsson

Clustering is one of the most fundamental tools in data science and machine learning, and k-means clustering is one of the most common such methods.

Clustering

Orthogonalization of data via Gromov-Wasserstein type feedback for clustering and visualization

no code implementations25 Jul 2022 Martin Ryner, Johan Karlsson

In this paper we propose an adaptive approach for clustering and visualization of data by an orthogonalization process.

Clustering Specificity

Quantifying and Computing Covariance Uncertainty

no code implementations6 Oct 2021 Filip Elvander, Johan Karlsson, Toon van Waterschoot

In this work, we consider the problem of bounding the values of a covariance function corresponding to a continuous-time stationary stochastic process or signal.

Mixed-Spectrum Signals -- Discrete Approximations and Variance Expressions for Covariance Estimates

no code implementations28 Jun 2021 Filip Elvander, Johan Karlsson

Furthermore, we consider approximating signals with arbitrary spectral densities by sequences of singular spectrum, i. e., sinusoidal, processes, and derive the limiting behavior of covariance estimates as both the sample size and the number of sinusoidal components tend to infinity.

Direction of Arrival Estimation

Incremental inference of collective graphical models

no code implementations26 Jun 2020 Rahul Singh, Isabel Haasler, Qinsheng Zhang, Johan Karlsson, Yongxin Chen

We consider incremental inference problems from aggregate data for collective dynamics.

Multi-marginal optimal transport and probabilistic graphical models

3 code implementations25 Jun 2020 Isabel Haasler, Rahul Singh, Qinsheng Zhang, Johan Karlsson, Yongxin Chen

We study multi-marginal optimal transport problems from a probabilistic graphical model perspective.

Bayesian Inference

Inference with Aggregate Data: An Optimal Transport Approach

no code implementations31 Mar 2020 Rahul Singh, Isabel Haasler, Qinsheng Zhang, Johan Karlsson, Yongxin Chen

Consequently, the celebrated Sinkhorn/iterative scaling algorithm for multi-marginal optimal transport can be leveraged together with the standard belief propagation algorithm to establish an efficient inference scheme which we call Sinkhorn belief propagation (SBP).

Automatic Target Recognition Using Discrimination Based on Optimal Transport

no code implementations6 Apr 2019 Ali Sadeghian, Deoksu Lim, Johan Karlsson, Jian Li

The use of distances based on optimal transportation has recently shown promise for discrimination of power spectra.

Data-driven nonsmooth optimization

1 code implementation2 Aug 2018 Sebastian Banert, Axel Ringh, Jonas Adler, Johan Karlsson, Ozan Öktem

In this work, we consider methods for solving large-scale optimization problems with a possibly nonsmooth objective function.

Optimization and Control 90C25 (Primary) 68T05, 47H05 (Secondary)

Learning to solve inverse problems using Wasserstein loss

1 code implementation30 Oct 2017 Jonas Adler, Axel Ringh, Ozan Öktem, Johan Karlsson

We propose using the Wasserstein loss for training in inverse problems.

Generalized Sinkhorn iterations for regularizing inverse problems using optimal mass transport

2 code implementations7 Dec 2016 Johan Karlsson, Axel Ringh

In particular we consider a limited-angle computerized tomography problem, where a priori information is used to compensate for missing measurements.

Optimization and Control 49N45, 90C25, 94A08

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