Prof. Dr. Rainer Gemulla

Chair of Practical Computer Science I: Data Analytics

Universität Mannheim
B6, 26, Room B 016
D-68159 Mannheim

Tel.: +49 621 181 2480


My PGP public key (id 0x81405E0B30302532)

I am heading the Chair of Practical Computer Science I: Data Analytics at the University of Mannheim. The chair is part of the Data and Web Science Group.


Go to: Research Interests, CV, PhD Students, Teaching, Awards, Professional Activities, Data and Software, Publications


If you consider applying to our lab, please read:

  • Applications should include CV, transcripts, and a short (!) cover letter or will be ignored.
  • We generally do not offer short interships (3 months or less). Applications for such internships will be ignored.
  • If you are a BSc or MSc student here, have very good transcripts, and are interested in a student job with us, contact me directly.

Research Interests

My research interests are mainly in machine learning and data processing. In particular:

  • Machine learning with structured data (such as relational data)
  • Machine learning with semi-structured data (such as multi-relational graphs)
  • Combining the above with unstructured knowledge (such as text)
  • Efficient and scalable methods and systems for data-intensive processing

Curriculum Vitae

Since 2014   W3-Professor for Practical Computer Science I, Universität Mannheim, Germany
2010 – 2014   Senior researcher / group leader, Max-Planck-Institut für Informatik, Saarbrücken, Germany
2008 – 2010   Postdoctoral researcher, IBM Almaden Research Center, San Jose, CA, USA
2004 – 2008   PhD in Computer Science, Technische Universität Dresden, Germany

PhD Students

Former PhD students

Kaustubh Beedkar, Luciano del Corro, Kiril Gashteovski, Stefan Kain, Adrian Kochsiek, Faraz Makari Manshadi, Alexander Renz-Wieland, Daniel Ruffinelli, Christina Teflioudi, Yanjie Wang

Teaching

If you are interested in writing a seminar, Bachelor or Master thesis with us, please read the following guidelines.

If you are within the intranet of University of Mannheim, you can access lecture videos / materials here. If not, ask me.

Upcoming semester (HWS26)

  • CS 560: Large-Scale Data Management (Master Course)
  • IE 675b: Machine Learning (Master course)
  • SM 445/CS707: Seminar “Machine Learning on Structured Data”  (Bachelor/Master seminar)
  • Data Analytics Team Project: Your Project, Your Team
  • Colloquium (for PhD candidates)

This semester (FSS26)

I am on sabbatical leave. The course “CS 303: Praktische Informatik II” is taught by Prof. Frederik Armknecht. The course “IE 678 Deep Learning” is taught by Prof. Margret Keuper. We are still offering:

Previous semester (HWS 2025)

And the one before (FSS 2025)

Previous courses (not taught anymore)

Awards

  • Distinguished Area Chair Award at ICDE, 2026
  • Distinguished Reviewer Award at SIGMOD, 2025
  • Distinguished PC Member Award at EDBT, 2023
  • Outstanding Reviewer Award at NeurIPS, 2021
  • Named Distinguished PC Member for SIGMOD, 2017
  • Junior-Fellow of the Gesellschaft für Informatik (GI), 2013
  • AWS in Education Research Grant Award, 2013
  • Busy Beaver teaching award (winter term 2012/2013)
    for Non-Traditional Data Management (NoSQL and more)
  • IBM's 2011 Pat Goldberg Memorial best paper award in CS, EE and Math
    (for “Large-Scale Matrix Factorization with Distributed Stochastic Gradient Descent” with P. J. Haas, E. Nijkamp, and Y. Sismanis; KDD 2011)
  • Best paper of NIPS 2011 Biglearn workshop
    (for “Large-Scale Matrix Factorization with Distributed Stochastic Gradient Descent” with P. J. Haas, Y. Sismanis, C. Teflioudi, and F. Makari)
  • Google Focused Research Award 2011: Robust and Scalable Fact Discovery from Web Sources
    (with G. Weikum and M. Theobald)
  • Research Highlight in Communications of the ACM
    (for “Distinct-Value Synopses for Multiset Operations” with K. Beyer, P.J. Haas, B. Reinwald, Y. Sismanis)
  • The VLDB Journal, Special Issue: Best Papers of VLDB 2006
    (for “A Dip in the Reservoir: Maintaining Sample Synopses of Evolving Datasets” with W. Lehner and P.J. Haas)

Professional Activities

Administration

  • Head of examination board: MSc Business Informatics (since 2017)
  • Member of examination board: BSc Business Informatics (since 2017 or earlier), Mannheim Master in Data Science (since 2017)
  • Member of selection commitee: BSc and MSc Business Informatics (since 2017 or earlier), Mannheim Master in Data Science (since 2024)
  • Information officer of the WIM faculty: since 2022
  • Embassador of the German Informatics Society (GI): since 2017
  • CIO of University of Mannheim: 2022–2024
  • Study dean of the WIM faculty: 2016–2019
  • Member of the selection committee: Max Planck International Research School (2010–2014)

Organizer

Young academics

  • One-day workshop “Machine Learning Systems” at Jugendforum BW 2024
  • Mentor of Junior Professors: Roland Leißa (2021–2025), Margret Keuper (2017–2021), Goran Glavaš (2017–2021)
  • Mentor in the mentoring program of the German Informatics Society (GI, since 2020)
  • Member of task committee and final-round jury of BWINF (since 2010)
  • Member of the board of BWINF (2014–2022)

Associate editor / area chair

  • VLDB: 2027, 2021, 2019, 2015
  • ICDE: 2026
  • IJCAI: 2025
  • TKDE: 2015–2018
  • DASP: 2018
  • EDBT: 2017
  • JISA: 2016
  • CIKM: 2014

PC member / reviewer (since 2011)

  • 2027: SIGMOD
  • 2026: EDBT, ICLR, ICML, SIGMOD, TMLR, VLDB
  • 2025: DEEM@SIGMOD, EDBT, ICLR, ICML, LLM+Graph@VLDB,NeurIPS, SIGMOD, STACS, TMLR, VLDB
  • 2024: ARR, DAMI, DEEM, ICLR, IJCAI, LLM+KG, NeurIPS, SIGMOD, TMLR, VLDBJ
  • 2023: ARR, Artificial Intelligence, BTW, DEEM, EDBT, ICLR, IJCAI, Neural Networks, Repl4NLP, SIGMOD, TMLR, VLDB, VLDBJ
  • 2022: Artificial Intelligence, DEEM, EDBT, ICLR, IJCAI, KDML, Machine Learning, Pattern Recognition, SDM, SIGMOD, VLDBJ
  • 2021: DEEM, EDBT, ICDM, IJCAI, KDML, NeurIPS, SIGMOD (demo), Repl4NLP
  • 2020: AKBC, EDBT, IJCAI, LWDA, Repl4NLP, SUM, TPDS
  • 2019: AKBC, BTW, DEEM, IJCAI, INFORMATIK, LWDA, SUM
  • 2018: VLDB, EDBT, DEEM
  • 2017: SIGMOD, BTW, DEEM, TALG, VLDB, ECML-PKDD
  • 2016: SIGMOD, ECML-PKDD
  • 2015: BTW, DAMI, GvDB, IS, JODS, JWS, PODS
  • 2014: BDDC, BigData, Buda, DMC, JMLR, SIGMOD, VLDB
  • 2013: AKBC, BigData, BTW, CIKM, DMC, ICALP, TKDE, TML, VLDB
  • 2012: KDD, JMLR, TODS
  • 2011: BTW, IS, VLDB, VLDBJ

Data and Software

  • GraSH: Multi-fidelity HPO for graph learning
  • DistKGE: A knowledge graph embedding library for multi-GPU and multi-machine training
  • AdaPM: A fully adaptive parameter manager
  • LibKGE: A knowledge graph embedding library
  • Lapse: A parameter server with dynamic parameter allocation
  • OPIEC: An open information extraction corpus
  • MinIE: Open information extractor (spiritual successor to ClausIE)
  • DSGDpp: Various parallel algorithms for matrix factorization (including DSGD++)
  • DESQ: Frequent sequence mining with subsequence constraints
  • Rounding rank: algorithms for computing rounding-rank decompositions
  • CORE: Context-aware open relation extraction with factorization machines
  • FINET: Context-aware fine-grained named entity typing
  • Werdy: Recognition and Disambiguation of Verbs and Verb Phrases with Syntactic and Semantic Pruning
  • ClausIE: Clause-Based Open Information Extraction
  • LEMP: Fast Retrieval of Large Entries in a Matrix Product
  • LASH: Large-Scale Sequence Mining with Hierarchies
  • MG-FSM: Large-Scale Frequent Sequence Mining

Publications

See also Google Scholar and DBLP.

2026   S. Forbat, R. Gemulla
Is Graph Mixup Beneficial? Investigating Interpolation And Empirical Performance of Graph Mixup Methods [pdf, poster (PDF), resources]
ICML, 2026
 C. Meilicke, R. Gemulla, J. Naegelen, H. Stuckenschmidt
A Simple Baseline for Inductive Knowledge Base Completion [pdf, resources]
KR (short paper), 2026
 A. Berndt, V. Bekmyradov, R. Gemulla, M. Kessel, T. Bach, S. Baltes
Can We Classify Flaky Tests Using Only Test Code? An LLM-Based Empirical Study [pdf]
In SANER (RENE track), 2026
 A. Berndt, T. Bach, R. Gemulla, M. Kessel, S. Baltes
On the Flakiness of LLM-generated Tests for Industrial and Open-Source Database Management Systems [pdf]
In ICSE (SEIP track), 2026
2024   D. Ruffinelli, R. Gemulla
Beyond Link Prediction: On Pre-Training Knowledge Graph Embeddings [pdf, resources]
In Repl4NLP workshop, 2024
2023   A. Kochsiek, R. Gemulla
A Benchmark for Semi-Inductive Link Prediction in Knowledge Graphs [pdf, resources]
In EMNLP Findings, 2023
 A. Kochsiek, A. Saxena, I. Nair, R. Gemulla
Friendly Neighbors: Contextualized Sequence-to-Sequence Link Prediction [pdf, resources]
In Repl4NLP workshop, 2023
 A. Renz-Wieland, A. Kieslinger, R. Gericke, R. Gemulla, Z. Kaoudi, V. Markl
Good Intentions: Adaptive Parameter Management via Intent Signaling [pdf, resources]
In CIKM, 2023
2022   A. Kochsiek, F. Niesel, R. Gemulla
Start Small, Think Big: On Hyperparameter Optimization for Large-Scale Knowledge Graph Embeddings [pdf, resources]
In ECML-PKDD, 2022
 A. Saxena, A. Kochsiek, R. Gemulla
Sequence-to-Sequence Knowledge Graph Completion and Question Answering [pdf, , video, resources]
In ACL, pp. 2814-2828, 2022
 A. Renz-Wieland, R. Gemulla, Z. Kaoudi, V. Markl
NuPS: A Parameter Server for Machine Learning with Non-Uniform Parameter Access [pdf, resources]
In SIGMOD, pp. 481–495, 2022
2021   A. Kochsiek, R. Gemulla
Parallel Training of Knowledge Graph Embedding Models: A Comparison of Techniques [pdf, resources]
In PVLDB, 15(3), 2021
 A. Renz-Wieland, T. Drobisch, R. Gemulla, Z. Kaoudi, V. Markl
Just Move It! Dynamic Parameter Allocation in Action [pdf, demo]
In PVLDB (demo), 14(12), 2021.
2020   A. Renz-Wieland, R. Gemulla, S. Zeuch, V. Markl
Dynamic Parameter Allocation in Parameter Servers [pdf, resources]
In PVLDB, 13(12), pp. 1877-1890, 2020
 S. Broscheit, K. Gashteovski, Y. Wang, Rainer Gemulla
Can We Predict New Facts with Open Knowledge Graph Embeddings? A Benchmark for Open Link Prediction [pdf, resources]
In ACL, 2020
 D. Ruffinelli, S. Broscheit, R. Gemulla
You CAN Teach an Old Dog New Tricks! On Training Knowledge Graph Embeddings [pdf, video, resources, OpenReview]
In ICLR, 2020
 S. Broscheit, D. Ruffinelli, A. Kochsiek, P. Betz, R. Gemulla
LibKGE – A knowledge graph embedding library for reproducible research [pdf, resources]
In EMNLP (demo), 2020
 K. Gashteovski, R. Gemulla, B. Kotnis, S. Hertling, C. Meilicke
On Aligning OpenIE Extractions with Knowledge Bases: A Case Study [pdf, slides (PDF), resources]
In Eval4NLP, 2020
2019   Y. Wang, D. Ruffinelli, R. Gemulla, S. Broscheit, C. Meilicke
On Evaluating Embedding Models for Knowledge Base Completion [pdf]
In RepL4NLP workshop, 2019
 K. Beedkar, R. Gemulla, W. Martens
A Unified Framework for Frequent Sequence Mining with Subsequence Constraints [pdf (journal version), pdf (author version), resources
In TODS, 2019
 K. Gashteovski, S. Wanner, S. Hertling, S. Broscheit, R. Gemulla
OPIEC: An Open Information Extraction Corpus [pdf, poster (PDF), resources, OpenReview
In AKBC, 2019
 A. Renz-Wieland, M. Bertsch, R. Gemulla
Scalable Frequent Sequence Mining With Flexible Subsequence Constraints [pdf, poster (PDF)
In ICDE, 2019
Preprints
(2019)   
Y. Wang, S. Broscheit, R. Gemulla
A Relational Tucker Decomposition for Multi-Relational Link Prediction [arXiv]
2019
2018   C. Meilicke, M. Fink, Y. Wang, D. Ruffinelli, R. Gemulla, and H. Stuckenschmidt
Fine-grained Evaluation of Rule- and Embedding-based Systems for Knowledge Graph Completion [pdf, resources]
In ISWC, 2018
 J. Pfeiffer, S. Broscheit, R. Gemulla, M. Göschl
A Neural Autoencoder Approach for Document Ranking and Query Refinement in Pharmacogenomic Information Retrieval [pdf]
In BioNLP workshop, 2018
 S. Broscheit, R. Gemulla, M. Keuper
Learning Distributional Token Representations from Visual Features [pdf]
In RepL4NLP workshop, 2018
 Y. Wang, R. Gemulla, H. Li
On Multi-Relational Link Prediction with Bilinear Models [pdf, resources]
In AAAI, 2018
2017   K. Gashteovski, R. Gemulla, L. del Corro
MinIE: Minimizing Facts in Open Information Extraction [pdf, poster (PDF), resources]
In EMNLP, pp. 2620-2630, 2017
 C. Teflioudi, R. Gemulla
Exact and Approximate Maximum Inner Product Search with LEMP [pdf (journal version), pdf (author version), resources]
In TODS, 42(1) Art. 5, 2017
2016   S. Neumann, R. Gemulla, P. Miettinen
What You Will Gain By Rounding: Theory and Algorithms for Rounding Rank [pdf, tech report, resources]
In ICDM, pp. 380–389, 2016
 K. Beedkar, R. Gemulla
DESQ: Frequent Sequence Mining with Subsequence Constraints [pdf, tech report, resources]
In ICDM (short paper), pp. 793–798, 2016
2015   L. Del Corro, A. Abujabal, R. Gemulla, G. Weikum
FINET: Context-Aware Fine-Grained Named Entity Typing [pdf, slides (PDF), resources]
In EMNLP, pp. 868–878, 2015
 F. Petroni, L. Del Corro, R. Gemulla
CORE: Context-Aware Open Relation Extraction with Factorization Machines [pdf, slides (PDF), resources]
In EMNLP, pp. 1763-1773, 2015
 K. Beedkar, K. Berberich, R. Gemulla, I. Miliaraki
Closing the Gap: Sequence Mining at Scale [pdf (journal version), pdf (author version), resources]
In TODS, 40(2) Art. 8, 2015
 C. Teflioudi, R. Gemulla, O. Mykytiuk
LEMP: Fast Retrieval of Large Entries in a Matrix Product [pdf, slides (PDF), resources]
In SIGMOD, pp. 107–122, 2015
 K. Beedkar, R. Gemulla
LASH: Large-Scale Sequence Mining with Hierarchies [pdf, slides (PDF), resources]
In SIGMOD, pp. 491–503, 2015
 R. Gemulla
A Self-Portrayal of GI Junior Fellow Rainer Gemulla: Data Analysis at Scale [pdf (journal version), pdf (author version)]
it – Information Technology 57(2), pp. 130–132 , 2015
2014   L. Del Corro, R. Gemulla, G. Weikum
Werdy: Recognition and Disambiguation of Verbs and Verb Phrases with Syntactic and Semantic Pruning [pdf, resources]
In EMNLP, pp. 374–385, 2014
 P. Roy, J. Teubner, R. Gemulla
Low-Latency Handshake Join [pdf]
In PVLDB, 7(9), pp. 709–720, 2014
 L. Qu, Y. Zhang, R. Wang, L. Jiang, R. Gemulla, G. Weikum
Senti-LSSVM: Sentiment-Oriented Multi-Relation Extraction with Latent Structural SVM [pdf]
In TACL, 2, pp. 155–168, 2014
 D. Erdös, R. Gemulla, E. Terzi
Reconstructing Graphs from Neighborhood Data [pdf (author version), pdf (journal version)]
In TKDD, 8(4), 2014
2013   F. Makari, C. Teflioudi, R. Gemulla, P. J. Haas, Y. Sismanis
Shared-Memory and Shared-Nothing Stochastic Gradient Descent Algorithms for Matrix Completion [pdf (author version), pdf (journal version), resources]
In KAIS (special issue: best papers of ICDM 2012), pp. 1–31, 2013
 F. Makari, R. Gemulla
A Distributed Approximation Algorithm for Mixed Packing-Covering Linear Programs [pdf]
In NIPS 2013 Biglearn workshop (poster), 2013
 F. Makari, B. Awerbuch, R. Gemulla, R. Khandekar, J. Mestre, M. Sozio
A Distributed Algorithm for Large-Scale Generalized Matching [pdf, slides (PDF)]
The analysis of the number of binary search steps (Lemma 2) contains a bug; see our Biglearn paper (PDF) for a corrected version.
In PVLDB, 6(9), pp. 613–624, 2013
 I. Miliaraki, K. Berberich, R. Gemulla, S. Zoupanos
Mind the Gap: Large-Scale Frequent Sequence Mining [pdf, slides (PDF), resources]
In SIGMOD, pp. 797–808, 2013
 L. Del Corro, R. Gemulla
ClausIE: Clause-Based Open Information Extraction [pdf, slides (PDF), resources
In WWW, pp. 355–366, 2013
 R. Gemulla, P. J. Haas, W. Lehner
Non-Uniformity Issues and Workarounds in Bounded-Size Sampling [pdf (author version), pdf (journal version), resources
In The VLDB Journal, 22(6), pp. 753–772, 2013
 K. Beedkar, L. Del Corro, R. Gemulla 
Fully Parallel Inference in Markov Logic Networks [pdf]
In BTW, pp. 205–224, 2013
2012   D. Erdös, R. Gemulla, E. Terzi
Reconstructing Graphs from Neighborhood Data [pdf, slides (PDF)]
In ICDM, pp. 231–240, 2012
 C. Teflioudi, F. Makari, R. Gemulla
Distributed Matrix Completion [pdf, slides (PDF), resources]
In ICDM, pp. 655–664, 2012
 L. Qu, R. Gemulla, G. Weikum
A Weakly Supervised Model for Sentence-Level Semantic Orientation Analysis with Multiple Experts [pdf]
In EMNLP-CoNLL, pp. 149–159, 2012
2011   R. Gemulla, P. J. Haas, Y. Sismanis, C. Teflioudi, F. Makari
Large-Scale Matrix Factorization with Distributed Stochastic Gradient Descent [pdf, slides (PDF), resources]
In NIPS 2011 Biglearn workshop, 2011 (best paper award)

 
R. Gemulla, E. Nijkamp, P. J. Haas, Y. Sismanis
Large-Scale Matrix Factorization with Distributed Stochastic Gradient Descent [pdf, slides (PDF), resources]
In KDD, pp. 69–77, 2011

 
K. Beyer, V. Ercegovac, R. Gemulla, A. Balmin, M. Eltabakh, C.C. Kanne, F. Ozcan, E. Shekita
Jaql: A Scripting Language for Large Scale Semistructured Data Analysis [pdf]
In PVLDB (industrial track), 4(11), pp. 1272-1283, 2011

 
M. Y. Eltabakh, Y. Tian, F. Özcan, R. Gemulla, A. Krettek, J. McPherson
CoHadoop: Flexible Data Placement and Its Exploitation in Hadoop [pdf]
In PVLDB, 4(9), pp. 575–585, 2011

 
R. Gemulla, P. J. Haas, E. Nijkamp, Y. Sismanis
Large-Scale Matrix Factorization with Distributed Stochastic Gradient Descent [pdf]
IBM Research Report RJ10481, March 2011 Revised February, 2013

 
B. Schlegel, R. Gemulla, W. Lehner
Memory-Efficient Frequent-Itemset Mining [pdf]
In EDBT, pp. 461–472, 2011
2010   S. Das, Y. Sismanis, K. S. Beyer, R. Gemulla, P. J. Haas, J. McPherson.
Ricardo: Integrating R and Hadoop [pdf]
In SIGMOD (industrial track), pp. 987–998, 2010

 
B. Schlegel, R. Gemulla, W. Lehner.
Fast Integer Compression using SIMD Instructions [pdf]
In DAMON, pp. 34–40, 2010
2009   K. Beyer, R. Gemulla. P. J. Haas, B. Reinwald, Y. Sismanis.
Distinct-Value Synopses for Multiset Operations [pdf, technical perspective (PDF) by Surajit Chaudhuri]
In Commun. ACM, 52(10), pp. 87–95, 2009

 
B. Schlegel, R. Gemulla, W. Lehner.
k-Ary Search on Modern Processors [pdf, slides (PPTX)]
In DAMON, pp. 52–60, 2009
2008   R. Gemulla.
Sampling Algorithms for Evolving Datasets [pdf, summary (PDF), slides (PPTX)]
Ph.D. thesis, Technische Universität Dresden, 2009 
URL for citations: nbn-resolving.de/urn:nbn:de:bsz:14-ds-1224861856184-11644

 
R. Gemulla, P. Rösch and W. Lehner.
Linked Bernoulli Synopses: Sampling Along Foreign Keys [pdf, slides (PPTX)]
In SSDBM, pp. 6–23, 2008

 
R. Gemulla and W. Lehner.
Sampling Time-Based Sliding Windows in Bounded Space [pdf, slides (PPTX)]
As observed by Hu et al., the lower bound of Ω(k log N) stated in Theorem 1 should read Ω(k log(N/k)). 
In SIGMOD, pp. 379–392, 2008

 
P. Rösch, R. Gemulla and W. Lehner.
Designing Random Sample Synopses with Outliers [pdf, poster (PDF)]
In ICDE (poster), pp. 1400-1402, 2008
2007   R. Gemulla, W. Lehner and P.J. Haas.
Maintaining Bounded-Size Sample Synopses of Evolving Datasets [pdf]
The resizing algorithm proposed in this article contains a bug; see my Ph.D. thesis (PDF) or our 2013 VLDB Journal (PDF) paper for a corrected version.
In The VLDB Journal, Special Issue: Best Papers of VLDB 2006, pp. 173–201, 2007

 
K. Beyer, P. J. Haas, B. Reinwald, Y. Sismanis and R. Gemulla.
On Synopses for Distinct-Value Estimation Under Multiset Operations [pdf, slides (PPT)]
In SIGMOD, pp. 199–210, 2007

 
R. Gemulla, W. Lehner and P. J. Haas.
Maintaining Bernoulli Samples over Evolving Multisets [pdf, slides (PPT)]
In PODS, pp. 93–102, 2007
2006   R. Gemulla, W. Lehner and P. J. Haas.
A Dip in the Reservoir: Maintaining Sample Synopses of Evolving Datasets [pdf, slides (PPT)]
In VLDB, pp. 595–606, 2006

 
A. Klein, R. Gemulla, P. Rösch and W. Lehner.
Derby/S: A DBMS for Sample-Based Query Answering [pdf, poster1 (PDF), poster2 (PDF)]
In SIGMOD (demo), pp. 757–759, 2006

 
R. Gemulla and W. Lehner.
Deferred Maintenance of Disk-Based Random Samples [pdf, slides (PPT)]
In EDBT, pp. 423–441, 2006

Kontakt

Prof. Dr. Rainer Gemulla

Prof. Dr. Rainer Gemulla

Chair of Practical Computer Science I: Data Analytics
University of Mannheim
School of Business Informatics and Mathematics
B 6, 26 – Room B 0.16
68159 Mannheim