no code implementations • 8 Dec 2023 • Giulia Baldini, Melanie Schmidt, Charlotte Zäske, Liliana L. Caldeira
The evaluation shows that the segmentation works well with synthesized scans (in particular, with Pix2Pix methods) in many cases.
no code implementations • 2 Sep 2023 • Lukas Drexler, Annika Hennes, Abhiruk Lahiri, Melanie Schmidt, Julian Wargalla
We propose a PTAS for the fair $k$-min-sum-radii problem in Euclidean spaces of arbitrary dimension for the case of constant $k$.
no code implementations • 14 Jun 2021 • Melanie Schmidt, Julian Wargalla
There have been recent efforts to design unified algorithms to solve constrained $k$-means problems without using knowledge of the specific constraint at hand aside from mild assumptions like the polynomial computability of feasibility under the constraint (compute if a clustering satisfies the constraint) or the presence of an efficient assignment oracle (given a set of centers, produce an optimal assignment of points to the centers which satisfies the constraint).
no code implementations • 2 Dec 2019 • Anup Bhattacharya, Jan Eube, Heiko Röglin, Melanie Schmidt
We show that this is not the case by presenting a family of instances on which greedy k-means++ yields only an $\Omega(\ell\cdot \log k)$-approximation in expectation where $\ell$ is the number of possible centers that are sampled in each iteration.
no code implementations • 11 Jul 2019 • Anna Großwendt, Heiko Röglin, Melanie Schmidt
In this paper, we show that Ward's method computes a $2$-approximation with respect to the $k$-means objective function if the optimal $k$-clustering is well separated.
no code implementations • 26 Feb 2016 • Johannes Blömer, Christiane Lammersen, Melanie Schmidt, Christian Sohler
The $k$-means algorithm is one of the most widely used clustering heuristics.