Zobrazeno 1 - 10
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pro vyhledávání: '"Wiegele A"'
In the quadratic minimum spanning tree problem (QMSTP) one wants to find the minimizer of a quadratic function over all possible spanning trees of a graph. We give two formulations of the QMSTP as mixed-integer semidefinite programs exploiting the al
Externí odkaz:
http://arxiv.org/abs/2410.04997
Convexification techniques have gained increasing interest over the past decades. In this work, we apply a recently developed convexification technique for fractional programs by He, Liu and Tawarmalani (2024) to the problem of determining the edge e
Externí odkaz:
http://arxiv.org/abs/2410.02526
Computing the edge expansion of a graph is a famously hard combinatorial problem for which there have been many approximation studies. We present two variants of exact algorithms using semidefinite programming (SDP) to compute this constant for any g
Externí odkaz:
http://arxiv.org/abs/2403.04657
Given a linear ordering of the vertices of a graph, the cutwidth of a vertex $v$ with respect to this ordering is the number of edges from any vertex before $v$ (including $v$) to any vertex after $v$ in this ordering. The cutwidth of an ordering is
Externí odkaz:
http://arxiv.org/abs/2301.03900
The graph partition problem (GPP) aims at clustering the vertex set of a graph into a fixed number of disjoint subsets of given sizes such that the sum of weights of edges joining different sets is minimized. This paper investigates the quality of do
Externí odkaz:
http://arxiv.org/abs/2205.06788
Finding the stability number of a graph, i.e., the maximum number of vertices of which no two are adjacent, is a well known NP-hard combinatorial optimization problem. Since this problem has several applications in real life, there is need to find ef
Externí odkaz:
http://arxiv.org/abs/2108.05716
Autor:
Wiegele, Angelika, Zhao, Shudian
We model the cardinality-constrained portfolio problem using semidefinite matrices and investigate a relaxation using semidefinite programming. Experimental results show that this relaxation generates tight lower bounds and even achieves optimality o
Externí odkaz:
http://arxiv.org/abs/2107.11338
Autor:
Johannes Zipperle, Johannes Oesterreicher, Matthias Hackl, Teresa Lara Krammer, Helena Thumfart, Madhusudhan Reddy Bobbili, Marion Wiegele, Johannes Grillari, Marcin F. Osuchowski, Herbert Schöchl, Wolfgang Holnthoner, Christoph J. Schlimp, Judith Schiefer, Marco Valerio Pesce, Stefan Ulbing, Johannes Gratz
Publikováno v:
Intensive Care Medicine Experimental, Vol 11, Iss 1, Pp 1-13 (2023)
Abstract Extracellular vesicles (EVs) represent nanometer-sized, subcellular spheres, that are released from almost any cell type and carry a wide variety of biologically relevant cargo. In severe cases of coronavirus disease 2019 (COVID-19) and othe
Externí odkaz:
https://doaj.org/article/cb28aed88b57448d9e23e704c1ccd462
Autor:
Wiegele, Angelika, Zhao, Shudian
We study two NP-complete graph partition problems, $k$-equipartition problems and graph partition problems with knapsack constraints (GPKC). We introduce tight SDP relaxations with nonnegativity constraints to get lower bounds, the SDP relaxations ar
Externí odkaz:
http://arxiv.org/abs/2105.09075
Publikováno v:
INFORMS Journal on Computing, 2022
The minimum sum-of-squares clustering problem (MSSC) consists of partitioning $n$ observations into $k$ clusters in order to minimize the sum of squared distances from the points to the centroid of their cluster. In this paper, we propose an exact al
Externí odkaz:
http://arxiv.org/abs/2104.11542