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Archived entry

Prof. Dr. Ulrich Lang left the University of Cologne in 2023. This profile page serves as an archive and is not kept up-to-date.

Prof. Dr. Ulrich Lang

Simulations on high performance computers and instruments, such as microscopes and sequencers typically generate large volumes of data which needs to be processed and analyzed. HPC systems are characterized by a highly dynamic development of processor technologies and system architectures. Code kernels, e.g. in life science have specific requirements concerning IOPS, bandwidths, latencies, etc. Research is conducted, how these requirements can be optimally satisfied using actual hardware and software technologies and architectures. Within the BMBF project NGSgoesHPC (Next Generation Sequencing using High Performance Computing) alignment algorithms and their implementations have been optimized. The parallelization of searching in De Bruijn graph structures and for efficient Tour Bus algorithms have been implemented. This led to a significant reduction in execution times as well as memory requirement, while improving the quality of the results. Within the BMBF e:Med-Project SMOOSE research on performance enhancements applied to oncological kernel algorithms on actual processor architectures (such as FPGAs) have been conducted. Contributions to oncological algorithms such as SClust led to performance increases in orders of magnitude compared to actual other algorithms from the application domain. Within the actual BMBF HPC project ORKA-HPC OpenMP interfaces are developed to reduce the programming effort when using reconfigurable heterogeneous processor architectures.

Another research focus of Ulrich Lang and his group is the interactive visual analysis of spatially structured datasets using virtual reality displays (power walls, CAVEs and HMDs). Interaction requirements in medicine, biology, earth sciences, lead to efficient implementations of varying interaction methods. For stereotactical planning interactive visualization tools are developed that prevent penetration of blood vessels in the brain. The visualization of multimodal datasets of mouse or fly brains allows researchers in life science to detect interrelationships of structures. Interactive handling of large 3D datasets requires very efficient processing methods. Real-time surface ray tracing is pursued as a research domain. Developed methods are integrated into Visionaray, a ray tracing template library, that is available as open source. In cooperation with application scientist we optimize core algorithms in gene sequencing for parallel high-performance computing architectures, reducing memory footprints and processing times. Ulrich Lang holds a computer science chair, he is also director of RRZK, the Regional Computing Center of the University of Cologne. RRZK operates High Performance Computers, it is member of the Gauss Alliance, the association of high-performance computing centers in Germany.

Further information concerning research projects can be found at as well as at

Stereotactic planning: insertion of a stereotactic biopsy needle avoiding the penetration of blood vessels (data courtesy Department of Stereotactic and Functional Neurosurgery, University of Cologne).

Selected publications

  1. Zellmann S, Lang U; C++ Compile Time Polymorphism for Ray Tracing, Proceedings of the 22nd Symposium on Vision, Modelling and Visualization (VMV 2017), Bonn, Germany, September 25-27, 2017.
  2. Zellmann S, Wickeroth D, Lang U; Visionaray: A Cross-Platform Ray Tracing Template Library, Proceedings of the 10th Workshop on Software Engineering and Architectures for Realtime Interactive Systems (IEEE SEARIS 2017), Los Angeles, California, USA, March 19, 2017.
  3. Zellmann S, Hoevels M, Lang U; Ray Traced Volume Clipping Using Multi-Hit BVH Traversal, Proceedings of the Visualization and Data Analysis Conference 2017, Burlingame, USA
  4. Zellmann S, Percan Y, Lang U; Advanced texture filtering: a versatile framework for reconstructing multi-dimensional image data on heterogeneous architectures, Proceedings of the Visualization and Data Analysis conference (VDA) San Francisco, 2, 2015, DOI: 10.1117/12.2077927
  5. Peifer M, Hertwig F, Roels F, Dreidax D, Gartlgruber M, Menon R, Krämer A, Roncaioli JL, Sand F, Heuckmann JM, Ikram F, Schmidt R, Ackermann S, Engesser A, Kahlert Y, Vogel W, Altmüller J, Nürnberg P, Thierry-Mieg J, Thierry-Mieg D, Mariappan A, Heynck S, Mariotti E, Henrich KO, Glöckner C, Bosco G, Leuschner I, Schweiger MR, Savelyeva L, Watkins SC, Shao C, Bell E, Höfer T, Achter V, Lang U, Theissen J, Volland R, Saadati M, Eggert A, de Wilde B, Berthold F, Peng Z, Zhao C, Shi L, Ortmann M, Büttner R, Perner S, Hero B, Schramm A, Schulte JH, Herrmann C, O'Sullivan RJ, Westermann F, Thomas RK, Fischer M.; Telomerase activation by genomic rearrangements in high-risk neuroblastoma. Nature. 2015 Oct 14. doi: 10.1038/nature14980.
  6. George J, Lim JS, Jang SJ, Cun Y, Ozretic L, Kong G, Leenders F, Lu X, Fernández-Cuesta L, Bosco G, Müller C, Dahmen I, Jahchan NS, Park KS, Yang D, Karnezis AN, Vaka D, Torres A, Wang MS, Korbel JO, Menon R, Chun SM, Kim D, Wilkerson M, Hayes N, Engelmann D, Pützer P, Bos M, Michels S, Vlasic I, Seidel D, Pinther B, Schaub P, Becker C, Janine Altmüller J, Yokota J, Kohno T, Iwakawa R, Tsuta K, Noguchi M, Muley T, Hoffmann H, Schnabel PA, Petersen I, Yuan Chen Y, Soltermann A, Tischler V, Choi CM, Kim YH, Massion PP, Zou Y, Jovanovic D, Kontic M, Wright GM, Russell PA, Solomon B, Koch I, Lindner M, Muscarella LA, la Torre A, Field JK, Jakopovic M, Knezevic J, Castaños-Vélez E, Roz L, Pastorino U, Brustugun OT, Lund-Iversen M, Thunnissen E, Köhler K, Schuler M, Botling J, Sandelin M, Sanchez-Cespedes M, Salvesen HB, Achter V, Lang U, Bogus M, Schneider PM, Zander T, Ansén S, Hallek M, Wolf J, Vingron M, Yatabe Y, Travis WD, Nürnberg P, Reinhardt C, Perner S, Heukamp L, Büttner R, Haas SA, Brambilla E, Peifer M, Sage J, Thomas RK.; Comprehensive genomic profiles of small cell lung cancer. Nature. 2015 Aug 6;524(7563):47-53.
  7. Kawalia A, Motameny S, Wonczak S, Thiele H, Nieroda L, Jabbari K, Borowski S, Sinha V, Gunia W, Lang U, Achter V, Nürnberg P; Leveraging the power of high performance computing for next generation sequencing data analysis: tricks and twists from a high throughput exome workflow, PloS one 10 (5), e0126321, 2015
  8. Zellmann S, Lang U; A Comparison of GPU Box-Plane Intersection Algorithms for Direct Volume Rendering, The 14th IASTED International Conference on Computer Graphics and Imaging (CGIM), Innsbruck, Austria; 02/2013.
  9. Zellmann S, Lang U; A Software Architecture for Distributed Volume Rendering on HPC Systems. Proceedings of the 24th IASTED International Conference on Parallel and Distributed Computing and Systems (PDCS), Las Vegas, Nevada, USA, November 12-14, 2012.
  10. 10. Birkenheuer G, Blunk D, Breuers S, Brinkmann A, Santos Vieira I, Fels G, Gesing S, Grunzke R, Herres-Pawlis S, Kohlbacher O, Kruber N, Krüger J, Lang U, Packschies L, Müller-Pfefferkorn R, Schäfer R, Schmalz H-G, Steinke T, Warzecha K-D, Wewior M; MoSGrid - A Molecular Simulation Grid as a new tool in Computational Chemistry, Biology and Material Science, Journal of Cheminformatics 01/2011; 3:P14