Large-scale graph processing – Department of Informatics – DDIS https://www.uzh.ch/blog/ifi-ddis Dynamic and Distributed Information Systems Group Tue, 08 Aug 2023 21:14:00 +0000 en-US hourly 1 https://wordpress.org/?v=6.8.2 New Article in Nature Scientific Reports https://www.uzh.ch/blog/ifi-ddis/2023/08/08/new-article-in-nature-scientific-reports/ Tue, 08 Aug 2023 21:14:00 +0000 https://www.uzh.ch/blog/ifi-ddis/?p=813 The article “Active querying approach to epidemic source detection on contact networks” has been published in Nature Scientific Reports by DDIS alumni Dr. Martin Sterchi in collaboration with Lorenz Hilfiker, Rolf Grütter & Abraham Bernstein!

The paper’s problem of interest is the identification of an epidemic’s patient zero given a network of contacts and a set of infected individuals, under the assumptions that the infection states of only a few individuals are initially observed and the epidemic has evolved. To tackle this issue, they formulate the problem as an active querying problem and propose a number of active querying strategies inspired by active learning. Their results suggest that in the limited information scenario it is possible to achieve source inference performance comparable to when the infection states of all individuals are observed.

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New Article by Baumgartner et al. at the Journal of Web Semantics https://www.uzh.ch/blog/ifi-ddis/2022/08/09/new-article-by-baumgartner-et-al-at-the-journal-of-web-semantics/ Tue, 09 Aug 2022 15:29:38 +0000 https://www.uzh.ch/blog/ifi-ddis/?p=759 Congratulations to our colleagues Matthias Baumgartner, former DDIS PostDoc Daniele Dell’Aglio, Heiko Paulheim (University of Mannheim), and Abraham Bernstein on their new journal article “Towards the Web of Embeddings: Integrating multiple knowledge graph embedding spaces with FedCoder” at the Journal of Web Semantics!

Abstract: The Semantic Web is distributed yet interoperable: Distributed since resources are created and published by a variety of producers, tailored to their specific needs and knowledge; Interoperable as entities are linked across resources, allowing to use resources from different providers in concord. Complementary to the explicit usage of Semantic Web resources, embedding methods made them applicable to machine learning tasks. Subsequently, embedding models for numerous tasks and structures have been developed, and embedding spaces for various resources have been published. The ecosystem of embedding spaces is distributed but not interoperable: Entity embeddings are not readily comparable across different spaces. To parallel the Web of Data with a Web of Embeddings, we must thus integrate available embedding spaces into a uniform space.

Current integration approaches are limited to two spaces and presume that both of them were embedded with the same method — both assumptions are unlikely to hold in the context of a Web of Embeddings. In this paper, we present FedCoder— an approach that integrates multiple embedding spaces via a latent space. We assert that linked entities have a similar representation in the latent space so that entities become comparable across embedding spaces. FedCoder employs an autoencoder to learn this latent space from linked as well as non-linked entities.

Our experiments show that FedCoder substantially outperforms state-of-the-art approaches when faced with different embedding models, that it scales better than previous methods in the number of embedding spaces, and that it improves with more graphs being integrated whilst performing comparably with current approaches that assumed joint learning of the embeddings and were, usually, limited to two sources. Our results demonstrate that FedCoder is well adapted to integrate the distributed, diverse, and large ecosystem of embeddings spaces into an interoperable Web of Embeddings.

You can read the full article here.


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Presentation at The Web Conference 2019 https://www.uzh.ch/blog/ifi-ddis/2019/06/04/presentation-at-the-web-conference-2019/ Tue, 04 Jun 2019 08:52:18 +0000 http://www.uzh.ch/blog/ifi-ddis/?p=552

During May of this year, The Web Conference 2019 took place in San Francisco. Bibek Paudel, recent graduate of DDIS, was there to present a paper and poster titled ‘Iterative Learning Embeddings and Rules for Knowledge Graphs’. This paper was created in collaboration with —among others— visiting scholar Wen Zhang. We congratulate them on their successful work!

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Paper accepted at The Web Conference 2019 https://www.uzh.ch/blog/ifi-ddis/2019/02/15/paper-accepted-at-the-web-conference-2019/ Fri, 15 Feb 2019 14:30:11 +0000 http://www.uzh.ch/blog/ifi-ddis/?p=535 Coming May, another DDIS paper will be presented at the Web Conference 2019 in San Fransisco. The paper, titled ‘Iteratively Learning Embeddings and Rules for Knowledge Graph Reasoning’, is a collaboration between – among others – DDIS’s own Bibek Paudel and former visiting PhD Student Wen Zhang.

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Lorenz Fischer published his paper on automated configuration of distributed stream processing systems at Cluster 2015 https://www.uzh.ch/blog/ifi-ddis/2015/06/15/lorenz-fischer-published-his-paper-on-automated-configuration-of-distributed-stream-processing-systems-at-cluster-2015/ Mon, 15 Jun 2015 12:50:19 +0000 http://www.uzh.ch/blog/ifi-ddis/?p=294 The paper “Machines Tuning Machines: Configuring Distributed Stream Processors with Bayesian Optimization” by Lorenz Fischer, Shen Gao, and Abraham Bernstein was accepted at the IEEE Cluster 2015 conference.

The paper presents an approach based on bayesian optimization that automatically tunes the myriad of parameters that a distributed stream processing system exposes. The paper will soon be available on our publication page.

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Cosmin Basca successfully defends his thesis https://www.uzh.ch/blog/ifi-ddis/2015/06/15/cosmin-defense/ Mon, 15 Jun 2015 12:44:15 +0000 http://www.uzh.ch/blog/ifi-ddis/?p=290 On June 13 Cosmin Basca successfully defended his thesis “Federated SPARQL Query Processing. Reconciling Diversity, Flexibility and Performance on the Web of Data”. In his thesis Cosmin explores new, highly-efficient approaches for federated SPARQL querying. In particular Cosmin presents the Avalanche federated query processor.

Cosmin Basca

A Clearly relaxed Cosmin after the defense…

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TripleRush paper Successfully presented at WWW https://www.uzh.ch/blog/ifi-ddis/2015/05/22/triplerush-at-www/ Fri, 22 May 2015 06:03:36 +0000 http://www.uzh.ch/blog/ifi-ddis/?p=285 Freshly minted PhD Philip Stutz and DDIS student Bibek Paudel successfully presented TripleRush — a paper co-authored with Ela Verman and Abraham Bernstein — at the World Wide Web Conference in Florence.

TripleRush is a highly parallelized and distributed in-memory graph database (or triple store) that performs better than its competitors. It also has the special feature of being able to run sampling queries in the form of Random Walks with Restarts.

You can find all information about TripleRush in the paper, which is available at http://www.merlin.uzh.ch/publication/show/11663

Philip Stutz and Bibek Paudel presenting at WWW 2015

Philip Stutz and Bibek Paudel presenting at WWW 2015

 

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Philip Stutz passes his PhD defense https://www.uzh.ch/blog/ifi-ddis/2015/05/08/philip-stutz-passes-his-phd-defense/ Fri, 08 May 2015 07:39:54 +0000 http://www.uzh.ch/blog/ifi-ddis/?p=274 On May 4, 2015, DDIS PhD student Philip Stutz successfully passed his PhD defense. He defended his thesis called Scalable Graph Processing with SIGNAL/COLLECT, in which he introduces the scalable graph-processing framework Signal/Collect.

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Newly minted PhD Philip Stutz wearing his hat!

 

 

Congratulations!

 

ps. Philip’s image was added to the DDIS portrait gallery.

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Two Signal/Collect Papers Accepted https://www.uzh.ch/blog/ifi-ddis/2015/01/26/two-signalcollect-papers-accepted/ Mon, 26 Jan 2015 13:25:32 +0000 http://www.uzh.ch/blog/ifi-ddis/?p=263 This week was marked by great success for the Signal/Collect project, as two papers were published in major outlets.

First, the foundational paper of the Signal/Collect system was accepted by the Semantic Web Journal. The paper, provides a detailed description of Signal/Collect, introduces a number of algorithms, and provides a comparative scalability evaluation. You can find the latest draft here.

Second, a paper on TripleRush — a distributed, highly-parallel, in-memory Triplestore based on Signal/Collect  — was accepted to WWW 2015. A workshop version of the paper was presented at an ISWC 2012 workshop, which you can find here. We will post the final version in merlin as soon as we finished putting the final touches on the camera ready copy.

Congratulations to the authors Philip Stutz, Daniel Strebel, Bibek Paudel, and Ela Verman!

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