• Office: APB 3048
  • Phone: (+49) 351 / 463 38402
  • Fax: (+49) 351 / 463 38259
  • Email:

Research Interests

  • Time Series  Analysis
  • Forecasting Methods
  • Large-scale Time Series Data
  • Big Data Analytics

Publications (29)

  • Investigating the Usage of Formulae in Mathematical Answer Retrieval

    Investigating the Usage of Formulae in Mathematical Answer Retrieval.

    Reusch, A.; Gonsior, J.; Hartmann, C.; Lehner, W.

    To appear in European Conference on Information Retrieval .ECIR '24, Glasgow, Scotland.2024.

    @article{,
       author = {Anja Reusch and Julius Gonsior and Claudio Hartmann and Wolfgang Lehner},
       title = {Investigating the Usage of Formulae in Mathematical Answer Retrieval},
       booktitle = {European Conference on Information Retrieval },
       year = {2024},
       location = {Glasgow, Scotland}
    }

  • FASTgres: Making Learned Query Optimizer Hinting Effective.

    Woltmann, L.; Thiessat, J.; Hartmann, C.; Habich, D.; Lehner, W.

    In Proceedings of the VLDB Endowment.VLDB 2023PVLDB,3310-3322,2023.Links: PDF.

    @inproceedings{,
       author = {Lucas Woltmann and Jerome Thiessat and Claudio Hartmann and Dirk Habich and Wolfgang Lehner},
       title = {FASTgres: Making Learned Query Optimizer Hinting Effective},
       booktitle = {Proceedings of the VLDB Endowment},
       volume = {16},
       year = {2023},
       month = {8},
       pages = {3310--3322},
       url = {https://doi.org/10.14778/3611479.3611528},
       publisher = {PVLDB}
    }

  • Learned Selection Strategy for Lightweight Integer Compression Algorithms.

    Woltmann, L.; Damme, P.; Hartmann, C.; Habich, D.; Lehner, W.

    In Proceedings of the 26th International Conference on Extending Database Technology (EDBT 2023).EDBT 20232023.Links: PDF.

    @inproceedings{,
       author = {Lucas Woltmann and Patrick Damme and Claudio Hartmann and Dirk Habich and Wolfgang Lehner},
       title = {Learned Selection Strategy for Lightweight Integer Compression Algorithms},
       booktitle = {Proceedings of the 26th International Conference on Extending Database Technology (EDBT 2023)},
       year = {2023},
       month = {3},
       url = {https://dx.doi.org/10.48786/edbt.2023.47}
    }

  • PostBOUND: PostgreSQL with Upper Bound SPJ Query Optimization.

    Bergmann, R.; Hertzschuch, A.; Hartmann, C.; Habich, D.; Lehner, W.

    BTW'23, Dresden.Gesellschaft für Informatik, e.V.,2023.Links: https://dl.gi.de/handle/20.500.12116/40318.

    @inproceedings{,
       author = {Rico Bergmann and Axel Hertzschuch and Claudio Hartmann and Dirk Habich and Wolfgang Lehner},
       title = {PostBOUND: PostgreSQL with Upper Bound SPJ Query Optimization},
       year = {2023},
       month = {03},
       location = {Dresden},
       numpages = {22},
       url = {https://doi.org/10.18420/BTW2023-14},
       publisher = {Gesellschaft f\"{u}r Informatik, e.V.}
    }

  • Optimizing Query Processing in PostgreSQL Through Learned Optimizer Hints.

    Thiessat, J.; Woltmann, L.; Hartmann, C.; Habich, D.

    BTW 2023Gesellschaft für Informatik e.V.,1075-1081,2023.Links: https://doi.org/10.18420/BTW2023-74.

    @incollection{,
       author = {Jerome Thiessat and Lucas Woltmann and Claudio Hartmann and Dirk Habich},
       title = {Optimizing Query Processing in PostgreSQL Through Learned Optimizer Hints},
       series = {Lecture Notes in Informatics (LNI)},
       volume = {P-331},
       year = {2023},
       month = {3},
       pages = {1075--1081},
       url = {https://doi.org/10.18420/BTW2023-74},
       publisher = {Gesellschaft f\"{u}r Informatik e.V.}
    }

  • JumpXClass: Explainable AI for Jump Classification in Trampoline Sports.

    Woltmann, L.; Ferger, K.; Hartmann, C.; Lehner, W.

    In BTW 2023.2023.Links: https://dl.gi.de/handle/20.500.12116/40340.

    @inproceedings{,
       author = {Lucas Woltmann and Katja Ferger and Claudio Hartmann and Wolfgang Lehner},
       title = {JumpXClass: Explainable AI for Jump Classification in Trampoline Sports},
       booktitle = {BTW 2023},
       year = {2023},
       month = {3}
    }

  • Sensor-based jump detection and classification with machine learning in trampoline gymnastics.

    Woltmann, L.; Hartmann, C.; Lehner, W.; Rausch, P.; Ferger, K.

    In German Journal of Exercise and Sport Research.Springer,2022.Links: https://doi.org/10.1007/s12662-022-00866-3.

    @article{,
       author = {Lucas Woltmann and Claudio Hartmann and Wolfgang Lehner and Paul Rausch and Katja Ferger},
       title = {Sensor-based jump detection and classification with machine learning in trampoline gymnastics},
       journal = {German Journal of Exercise and Sport Research},
       year = {2022},
       month = {12},
       url = {https://doi.org/10.1007/s12662-022-00866-3},
       publisher = {Springer}
    }

  • Exercise assessment in trampoline sport by automated jump classification.

    Woltmann, L.; Ferger, K.; Hartmann, C.; Lehner, W.

    In spinfortec2022 : Tagungsband zum 14. Symposium der Sektion Sportinformatik und Sporttechnologie der Deutschen Vereinigung für Sportwissenschaft (dvs).spinfortec22, Chemnitz.2022.Links: https://nbn-resolving.org/urn:nbn:de:bsz:ch1-qucosa2-807539.

    @conference{,
       author = {Lucas Woltmann and Katja Ferger and Claudio Hartmann and Wolfgang Lehner},
       title = {Exercise assessment in trampoline sport by automated jump classification},
       booktitle = {spinfortec2022 : Tagungsband zum 14. Symposium der Sektion Sportinformatik und Sporttechnologie der Deutschen Vereinigung f\"{u}r Sportwissenschaft (dvs)},
       year = {2022},
       month = {10},
       location = {Chemnitz},
       url = {https://nbn-resolving.org/urn:nbn:de:bsz:ch1-qucosa2-807539}
    }

  • Turbo-Charging SPJ Query Plans with Learned Physical Join Operator Selections.

    Hertzschuch, A.; Hartmann, C.; Habich, D.; Lehner, W.

    VLDB Endowment,2022.

    @conference{,
       author = {Axel Hertzschuch and Claudio Hartmann and Dirk Habich and Wolfgang Lehner},
       title = {Turbo-Charging SPJ Query Plans with Learned Physical Join Operator Selections},
       year = {2022},
       month = {9},
       isbn = {978-1-4503-8343-1/21/06},
       numpages = {13},
       url = {https://vldb.org/pvldb/vol15/p2706-hertzschuch.pdf},
       publisher = {VLDB Endowment}
    }

  • Ingredient-based Forecast of Sold Dish Portions in Campus Canteen Kitchens.

    Woltmann, L.; Drechsel, J.; Hartmann, C.; Lehner, W.

    In 2022 IEEE 38th International Conference on Data Engineering Workshops (ICDEW).ICDE '222022.Links: https://ieeexplore.ieee.org/abstract/document/9814582.

    @inproceedings{,
       author = {Lucas Woltmann and Jonathan Drechsel and Claudio Hartmann and Wolfgang Lehner},
       title = {Ingredient-based Forecast of Sold Dish Portions in Campus Canteen Kitchens},
       booktitle = {2022 IEEE 38th International Conference on Data Engineering Workshops (ICDEW)},
       year = {2022},
       month = {05},
       url = {https://doi.org/10.1109/ICDEW55742.2022.00023}
    }

  • Aggregate-based Training Phase for ML-based Cardinality Estimation.

    Woltmann, L.; Hartmann, C.; Habich, D.; Lehner, W.

    In Datenbank Spektrum.Springer Berlin Heidelberg,1-13,2022.Links: https://link.springer.com/article/10.1007/s13222-021-00400-z.

    @article{,
       author = {Lucas Woltmann and Claudio Hartmann and Dirk Habich and Wolfgang Lehner},
       title = {Aggregate-based Training Phase for ML-based Cardinality Estimation},
       journal = {Datenbank Spektrum},
       volume = {22/1},
       year = {2022},
       month = {01},
       pages = {1--13},
       url = {https://doi.org/10.1007/s13222-021-00400-z},
       publisher = {Springer Berlin Heidelberg}
    }

  • Data Science Meets High-Tech Manufacturing – The BTW 2021 Data Science Challenge.

    Woltmann, L.; Hartmann, C.; Lehner, W.

    In Datenbank Spektrum.Springer Nature,1-6,2021.Links: https://link.springer.com/article/10.1007/s13222-021-00398-4.

    @article{,
       author = {Lucas Woltmann and Claudio Hartmann and Wolfgang Lehner},
       title = {Data Science Meets High-Tech Manufacturing \&\#8211; The BTW 2021 Data Science Challenge},
       journal = {Datenbank Spektrum},
       volume = {22},
       year = {2021},
       month = {12},
       pages = {1--6},
       numpages = {6},
       url = {https://doi.org/10.1007/s13222-021-00398-4},
       publisher = {Springer Nature}
    }

  • Aggregate-based Training Phase for ML-based Cardinality Estimation.

    Woltmann, L.; Hartmann, C.; Habich, D.; Lehner, W.

    In Lecture Notes in Informatics.BTW'21Gesellschaft für Informatik,2021.Links: https://dl.gi.de/handle/20.500.12116/35812.

    @inproceedings{,
       author = {Lucas Woltmann and Claudio Hartmann and Dirk Habich and Wolfgang Lehner},
       title = {Aggregate-based Training Phase for ML-based Cardinality Estimation},
       booktitle = {Lecture Notes in Informatics},
       year = {2021},
       month = {09},
       url = {https://dx.doi.org/10.18420/btw2021-07},
       publisher = {Gesellschaft f\"{u}r Informatik}
    }

  • PostCENN: PostgreSQL with Machine Learning Models for Cardinality Estimation.

    Woltmann, L.; Hartmann, C.; Habich, D.; Lehner, W.

    In Proceedings of the VLDB Endowment.In Proc. VLDB Endow.VLDB 2021VLDB Endowment,2715-2718,2021.Links: PDF.

    @inproceedings{,
       author = {Lucas Woltmann and Claudio Hartmann and Dirk Habich and Wolfgang Lehner},
       title = {PostCENN: PostgreSQL with Machine Learning Models for Cardinality Estimation},
       booktitle = {Proceedings of the VLDB Endowment},
       journal = {Proc. VLDB Endow.},
       volume = {14},
       year = {2021},
       month = {08},
       pages = {2715--2718},
       numpages = {4},
       url = {https://doi.org/10.14778/3476311.3476327},
       publisher = {VLDB Endowment}
    }

  • Simplicity Done Right for Join Ordering.

    Hertzschuch, A.; Hartmann, C.; Habich, D.; Lehner, W.

    2021.

    @inproceedings{,
       author = {Axel Hertzschuch and Claudio Hartmann and Dirk Habich and Wolfgang Lehner},
       title = {Simplicity Done Right for Join Ordering},
       year = {2021},
       month = {1},
       url = {http://cidrdb.org/cidr2021/papers/cidr2021_paper01.pdf}
    }

  • Best of both worlds: combining traditional and machine learning models for cardinality estimation.

    Woltmann, L.; Hartmann, C.; Habich, D.; Lehner, W.

    In Proceedings of the Second International Workshop on Exploiting Artificial Intelligence Techniques for Data Management.SIGMOD aiDM '202020.Links: https://doi.org/10.1145/3401071.3401658.

    @inproceedings{,
       author = {Lucas Woltmann and Claudio Hartmann and Dirk Habich and Wolfgang Lehner},
       title = {Best of both worlds: combining traditional and machine learning models for cardinality estimation},
       booktitle = {Proceedings of the Second International Workshop on Exploiting Artificial Intelligence Techniques for Data Management},
       year = {2020},
       month = {6},
       url = {https://doi.org/10.1145/3401071.3401658}
    }

  • Feature-aware forecasting of large-scale time series data sets.

    Hartmann, C.; Kegel, L.; Lehner, W.

    In it - Information Technology.2020.

    @article{,
       author = {Claudio Hartmann and Lars Kegel and Wolfgang Lehner},
       title = {Feature-aware forecasting of large-scale time series data sets},
       journal = {it - Information Technology},
       year = {2020},
       month = {6},
       url = {https://doi.org/10.1515/itit-2019-0035}
    }

  • Particulate Matter Matters – The Data Science Challenge @ BTW 2019.

    Woltmann, L.; Hartmann, C.; Lehner, W.

    In Datenbank-Spektrum.Springer Berlin Heidelberg,(S. 165-182),2019.Links: https://link.springer.com/article/10.1007/s13222-019-00322-x.

    @article{,
       author = {Lucas Woltmann and Claudio Hartmann and Wolfgang Lehner},
       title = {Particulate Matter Matters \&\#8211; The Data Science Challenge @ BTW 2019},
       journal = {Datenbank-Spektrum},
       volume = {19},
       year = {2019},
       month = {08},
       pages = {(S. 165-182)},
       url = {https://doi.org/10.1007/s13222-019-00322-x},
       publisher = {Springer Berlin Heidelberg}
    }

  • Cardinality estimation with local deep learning models.

    Woltmann, L.; Hartmann, C.; Thiele, M.; Habich, D.; Lehner, W.

    In Proceedings of the Second International Workshop on Exploiting Artificial Intelligence Techniques for Data Management.SIGMOD aiDM '192019.Links: https://dl.acm.org/citation.cfm?id=3329875.

    @inproceedings{,
       author = {Lucas Woltmann and Claudio Hartmann and Maik Thiele and Dirk Habich and Wolfgang Lehner},
       title = {Cardinality estimation with local deep learning models},
       booktitle = {Proceedings of the Second International Workshop on Exploiting Artificial Intelligence Techniques for Data Management},
       year = {2019},
       month = {7},
       url = {https://doi.org/10.1145/3329859.3329875},
       acmid = {3329875}
    }

  • Assessing the Impact of Driving Bans with Data Analysis.

    Woltmann, L.; Hartmann, C.; Lehner, W.

    In BTW 2019 – Workshopband.Gesellschaft für Informatik,(S. 287-296),2019.Links: https://dl.gi.de/handle/20.500.12116/21599.

    @inproceedings{,
       author = {Lucas Woltmann and Claudio Hartmann and Wolfgang Lehner},
       title = {Assessing the Impact of Driving Bans with Data Analysis},
       booktitle = {BTW 2019 – Workshopband.},
       year = {2019},
       month = {3},
       isbn = {978-3-88579-684-8},
       location = {Bonn},
       pages = {(S. 287-296)},
       url = {https://dx.doi.org/10.18420/btw2019-ws-31},
       publisher = {Gesellschaft f\"{u}r Informatik}
    }

  • Large-Scale Time Series Analytics – Novel Approaches for Generation and Prediction.

    Hahmann, M.; Hartmann, C.; Kegel, L.; Lehner, W.

    In Datenbank-Spektrum.2019.Links: Download.

    @article{,
       author = {Martin Hahmann and Claudio Hartmann and Lars Kegel and Wolfgang Lehner},
       title = {Large-Scale Time Series Analytics \&\#8211; Novel Approaches for Generation and Prediction},
       journal = {Datenbank-Spektrum},
       year = {2019},
       month = {1},
       url = {https://doi.org/10.1007/s13222-018-00304-5}
    }

  • CSAR: the cross-sectional autoregression model for short and long-range forecasting.

    Hartmann, C.; Hahmann, M.; Habich, D.; Lehner, W.

    In International Journal of Data Science and Analytics.2019.

    @article{,
       author = {Claudio Hartmann and Martin Hahmann and Dirk Habich and Wolfgang Lehner},
       title = {CSAR: the cross-sectional autoregression model for short and long-range forecasting},
       journal = {International Journal of Data Science and Analytics},
       year = {2019},
       month = {1},
       url = {https://doi.org/10.1007/s41060-018-00169-7}
    }

  • CSAR: The Cross-sectional Autoregression Model.

    Hartmann, C.; Hahmann, M.; Habich, D.; Lehner, W.

    In 4th IEEE International Conference on Data Science and Advanced Analytics.DSAA'17, Tokyo, Japan.2017.

    @proceedings{,
       author = {Claudio Hartmann and Martin Hahmann and Dirk Habich and Wolfgang Lehner},
       title = {CSAR: The Cross-sectional Autoregression Model},
       booktitle = {4th IEEE International Conference on Data Science and Advanced Analytics},
       year = {2017},
       month = {10},
       location = {Tokyo, Japan}
    }

  • Challenges for Context-Driven Time Series Forecasting.

    Ulbricht, R.; Donker, H.; Hartmann, C.; Hahmann, M.; Lehner, W.

    In J. Data and Information Quality.2016.

    @article{,
       author = {Robert Ulbricht and Hilko Donker and Claudio Hartmann and Martin Hahmann and Wolfgang Lehner},
       title = {Challenges for Context-Driven Time Series Forecasting},
       journal = {J. Data and Information Quality},
       volume = {7},
       year = {2016},
       url = {http://doi.acm.org/10.1145/2896822}
    }

  • Big by blocks: modular analytics.

    Hahmann, M.; Hartmann, C.; Kegel, L.; Habich, D.; Lehner, W.

    In it - Information Technology.176-185,2016.

    @article{,
       author = {Martin Hahmann and Claudio Hartmann and Lars Kegel and Dirk Habich and Wolfgang Lehner},
       title = {Big by blocks: modular analytics},
       journal = {it - Information Technology},
       volume = {58},
       year = {2016},
       pages = {176--185},
       url = {http://dx.doi.org/10.1515/itit-2016-0003}
    }

  • Web-based Benchmarks for Forecasting Systems: The ECAST Platform.

    Ulbricht, R.; Hartmann, C.; Hahmann, M.; Donker, H.; Lehner, W.

    In Proceedings of the 2016 International Conference on Management of Data, SIGMOD Conference 2016, San Francisco, CA, USA, June 26 - July 01, 2016.özcan, Fatma; Koutrika, Georgia & Madden, Sam,2169-2172,2016.

    @article{,
       author = {Robert Ulbricht and Claudio Hartmann and Martin Hahmann and Hilko Donker and Wolfgang Lehner},
       title = {Web-based Benchmarks for Forecasting Systems: The ECAST Platform},
       booktitle = {Proceedings of the 2016 International Conference on Management of Data, SIGMOD Conference 2016, San Francisco, CA, USA, June 26 - July 01, 2016},
       year = {2016},
       isbn = {978-1-4503-3531-7},
       pages = {2169--2172},
       url = {http://doi.acm.org/10.1145/2882903.2899399},
       publisher = {\"{o}zcan, Fatma; Koutrika, Georgia \& Madden, Sam}
    }

  • Exploiting big data in time series forecasting: A cross-sectional approach.

    Hartmann, C.; Hahmann, M.; Rosenthal, F.; Lehner, W.

    In 2015 IEEE International Conference on Data Science and Advanced Analytics, DSAA 2015, Campus des Cordeliers, Paris, France, October 19-21, 2015.2015.

    @proceedings{,
       author = {Claudio Hartmann and Martin Hahmann and Frank Rosenthal and Wolfgang Lehner},
       title = {Exploiting big data in time series forecasting: A cross-sectional approach},
       booktitle = {2015 IEEE International Conference on Data Science and Advanced Analytics, DSAA 2015, Campus des Cordeliers, Paris, France, October 19-21, 2015},
       year = {2015},
       month = {10},
       isbn = {978-1-4673-8272-4},
       url = {http://dx.doi.org/10.1109/DSAA.2015.7344786}
    }

  • Aktuellen Zuständen von Märkten auf der Spur: Analyseinstrumente zur Erfassung dynamischer Marktdaten.

    Hartmann, C.; Rosenthal, F.; Hahmann, M.; Kirsche, T.; Lehner, W.

    In 50. Kongress der Deutschen Marktforschung (BVM-Kongress 2015, Berlin, Germany).2015.

    @article{,
       author = {Claudio Hartmann and Frank Rosenthal and Martin Hahmann and Thomas Kirsche and Wolfgang Lehner},
       title = {Aktuellen Zust\"{a}nden von M\"{a}rkten auf der Spur: Analyseinstrumente zur Erfassung dynamischer Marktdaten},
       booktitle = {50. Kongress der Deutschen Marktforschung (BVM-Kongress 2015, Berlin, Germany)},
       year = {2015}
    }

  • Forecasting the data cube: A model configuration advisor for multi-dimensional data sets.

    Fischer, U.; Schildt, C.; Hartmann, C.; Lehner, W.

    In 29th IEEE International Conference on Data Engineering, ICDE 2013, Brisbane, Australia, April 8-12, 2013.Jensen, Christian S.; Jermaine, Christopher M. & Zhou, Xiaofang,853-864,2013.

    @article{,
       author = {Ulrike Fischer and Christopher Schildt and Claudio Hartmann and Wolfgang Lehner},
       title = {Forecasting the data cube: A model configuration advisor for multi-dimensional data sets},
       booktitle = {29th IEEE International Conference on Data Engineering, ICDE 2013, Brisbane, Australia, April 8-12, 2013},
       year = {2013},
       isbn = {978-1-4673-4909-3},
       pages = {853--864},
       url = {http://dx.doi.org/10.1109/ICDE.2013.6544880},
       publisher = {Jensen, Christian S.; Jermaine, Christopher M. \& Zhou, Xiaofang}
    }

Research Projects (3)

Diploma Theses (5)

Master's Theses (3)

Bachelor's Theses (12)

Student Project Theses (4)