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Université de Fribourg

Reducing the Domination Number of Graphs via Edge Contractions

Galby, Esther ; Lima, Paloma T. ; Ries, Bernard

In: 44th International Symposium on Mathematical Foundations of Computer Science (MFCS 2019) - LIPICS Vol. 138, 2019, p. 41:1-41:13

In this paper, we study the following problem: given a connected graph G, can we reduce the domination number of G by at least one using k edge contractions, for some fixed integer k >= 0? We show that for k <= 2, the problem is coNP-hard. We further prove that for k=1, the problem is W[1]-hard parameterized by the size of a minimum dominating set plus the mim-width of the input graph, and that...

Public access from Sep 15, 2021
Université de Fribourg

Maximum eccentric connectivity index for graphs with given diameter

Hauweele, Pierre ; Hertz, Alain ; Mélot, Hadrien ; Ries, Bernard ; Devillez, Gauvain

In: Discrete Applied Mathematics, 2019, vol. 268, p. 102-111

The eccentricity of a vertex v in a graph G is the maximum distance between v and any other vertex of G. The diameter of a graph G is the maximum eccentricity of a vertex in G. The eccentric connectivity index of a connected graph is the sum over all vertices of the product between eccentricity and degree. Given two integers n and D with D ≤ n−1, we characterize those graphs which have...

Université de Fribourg

Reducing the Domination Number of Graphs via Edge Contractions

Galby, Esther ; Lima, Paloma T. ; Ries, Bernard

In: 44th International Symposium on Mathematical Foundations of Computer Science (MFCS 2019), 2014, no. 41, p. 1-13

In this paper, we study the following problem: given a connected graph G, can we reduce the domination number of G by at least one using k edge contractions, for some fixed integer k >=0? We show that for k <=2, the problem is coNP-hard. We further prove that for k = 1, the problem is W[1]-hard parameterized by the size of a minimum dominating set plus the mim-width of the input graph, and...

Université de Fribourg

APCNN: Tackling Cclass imbalance in relation extraction through aggregated piecewise convolutional neural networks

Smirnova, Alisa ; Audiffren, Julien ; Cudre-Mauroux, Philippe

In: 2019 6th Swiss Conference on Data Science (SDS), 2019, p. 63–68

One of the major difficulties in applying distant supervision to relation extraction is class imbalance, as the distribution of relations appearing in text is heavily skewed. This is particularly damaging for the multi-instance variant of relation extraction. In this work, we introduce a new model called Aggregated Piecewise Convolutional Neural Networks, or APCNN, to address this problem....

Université de Fribourg

Nodesketch: highly-efficient graph embeddings via recursive sketching

Yang, Dingqi ; Rosso, Paolo ; Li, Bin ; Cudre-Mauroux, Philippe

In: Proceedings of the 25th ACM SIGKDD International Conference on Knowledge Discovery & Data Mining, 2019, p. 1162–1172

Embeddings have become a key paradigm to learn graph representations and facilitate downstream graph analysis tasks. Existing graph embedding techniques either sample a large number of node pairs from a graph to learn node embeddings via stochastic optimization, or factorize a high-order proximity/adjacency matrix of the graph via expensive matrix factorization. However, these techniques...

Université de Fribourg

Non-parametric class completeness estimators for collaborative knowledge graphs — the case of wikidata

Luggen, Micheal ; Difallah, Djellel ; Sarasua, Cristina ; Demartini, Gianluca

In: The Semantic Web – ISWC 2019, 2019, p. -

Collaborative Knowledge Graph platforms allow humans and automated scripts to collaborate in creating, updating and interlinking entities and facts. To ensure both the completeness of the data as well as a uniform coverage of the different topics, it is crucial to identify underrepresented classes in the Knowledge Graph. In this paper, we tackle this problem by developing statistical...

Université de Fribourg

Visualizing semantic data

Luggen, Michael

In: Visualizing Semantic Data, 2018, p. 1-6

Visualizing semantic data describes the task of using the additional self describing features of semantic data (Linked Data/RDF) to inform the process of creating vector or bitmap drawings.

Université de Fribourg

Primary care patients’ use of conventional and complementary medicine for chronic low back pain

Rodondi, Pierre-Yves ; Bill, Anne-Sylvie ; Danon, Nadia ; Dubois, Julie ; Pasquier, Jérôme ; Matthey-de-l'Endroit, Florence ; Herzig, Lilli ; Burnand, Bernard

In: Journal of Pain Research, 2019, vol. Volume 12, p. 2101–2112

To investigate among primary care patients and their physicians in western Switzerland the prevalence of use, perceived usefulness, and communication about common treatments for chronic or recurrent low back pain (crLBP) including complementary medicine (CM). Patients and methods: A cross-sectional cluster observational study involving 499 crLBP patients visiting 45 primary care physicians...

Université de Fribourg

Resolute zotarolimus‐eluting stent in ST‐elevation myocardial infarction (resolute‐STEMI): A prespecified prospective register from the DAPT‐STEMI trial

Postma, Warner ; Fabris, Enrico ; Ent, Martin Van der ; Hermanides, Rik ; Buszman, Pawel ; Birgelen, Clemens Von ; Cook, Stephane ; Wedel, Hans ; Luca, Giuseppe De ; Delewi, Ronak ; Zijlstra, Felix ; Kedhi, Elvin

In: Catheterization and Cardiovascular Interventions, 2019, p. ccd.28376

To evaluate the safety and efficacy outcomes after primary percutaneous coronary intervention (pPCI) with second‐generation Resolute™ zotarolimus‐eluting stent (R‐ ZES) in patients enrolled in the DAPT‐STEMI Trial (NCT01459627).Background: R‐ ZES is one of the most used drug eluting stents worldwide. To date, the safety and efficacy data of this stent in setting of STEMI is...

Université de Fribourg

Absorb bioresorbable scaffold versus xience metallic stent for prevention of restenosis following percutaneous coronary intervention in patients at high risk of restenosis: rationale and design of the COMPARE ABSORB trial

Chang, Chun Chin ; Onuma, Yoshinobu ; Achenbach, Stephan ; Barbato, Emanuele ; Chevalier, Bernard ; Cook, Stéphane ; Dudek, Dariusz ; Escaned, Javier ; Gori, Tommaso ; Kočka, Viktor ; Tarantini, Giuseppe ; E.J.West, Nick ; Morice, Marie-Claude ; G.P.Tijssen, Jan ; Geuns, Robert-Janvan ; C.Smits, Pieter

In: Cardiovascular Revascularization Medicine, 2019, vol. 20, no. 7, p. 577–582

Background: The advent of bioresorbable vascular scaffolds (BVS) was considered as a potential improvement in percutaneous coronary intervention (PCI) after the groundbreaking development of drug eluting stents (DES). However, the clinical performance, long-term safety and efficacy of BVS in complex coronary lesions remain uncertain. COMPARE ABSORB, a multicenter, single blind, prospective ...