[{"date_updated":"2026-03-25T11:50:31Z","oa":"1","volume":1,"author":[{"last_name":"Ehtesabi","full_name":"Ehtesabi, Sadaf","id":"116116","first_name":"Sadaf"},{"last_name":"Hossain","orcid":"https://orcid.org/0000-0002-0737-7981","full_name":"Hossain, Manoar","id":"114619","first_name":"Manoar"},{"full_name":"Kenter, Tobias","id":"3145","last_name":"Kenter","first_name":"Tobias"},{"first_name":"Andreas","id":"15275","full_name":"Krawinkel, Andreas","last_name":"Krawinkel"},{"last_name":"Ostermann","full_name":"Ostermann, Lukas","id":"69976","first_name":"Lukas"},{"full_name":"Plessl, Christian","id":"16153","last_name":"Plessl","orcid":"0000-0001-5728-9982","first_name":"Christian"},{"first_name":"Heinrich","last_name":"Riebler","full_name":"Riebler, Heinrich","id":"8961"},{"id":"34009","full_name":"Rohde, Stefan","last_name":"Rohde","first_name":"Stefan"},{"first_name":"Robert","id":"75963","full_name":"Schade, Robert","orcid":"0000-0002-6268-5397","last_name":"Schade"},{"first_name":"Michael","full_name":"Schwarz, Michael","id":"5312","last_name":"Schwarz"},{"last_name":"Simon","full_name":"Simon, Jens","id":"15273","first_name":"Jens"},{"full_name":"Winnwa, Nils","id":"61189","last_name":"Winnwa","first_name":"Nils"},{"first_name":"Alex","last_name":"Wiens","orcid":"0000-0003-1764-9773","full_name":"Wiens, Alex","id":"23522"},{"last_name":"Wu","id":"77439","full_name":"Wu, Xin","first_name":"Xin"}],"doi":"10.48550/ARXIV.2512.07401","has_accepted_license":"1","publication_status":"published","place":"Paderborn","page":"33","intvolume":"         1","citation":{"chicago":"Ehtesabi, Sadaf, Manoar Hossain, Tobias Kenter, Andreas Krawinkel, Lukas Ostermann, Christian Plessl, Heinrich Riebler, et al. <i>Otus Supercomputer</i>. Vol. 1. PC2 Tech­nic­al Re­port Series. Paderborn: Paderborn Center for Parallel Computing (PC2), 2025. <a href=\"https://doi.org/10.48550/ARXIV.2512.07401\">https://doi.org/10.48550/ARXIV.2512.07401</a>.","ieee":"S. Ehtesabi <i>et al.</i>, <i>Otus Supercomputer</i>, vol. 1. Paderborn: Paderborn Center for Parallel Computing (PC2), 2025.","ama":"Ehtesabi S, Hossain M, Kenter T, et al. <i>Otus Supercomputer</i>. Vol 1. Paderborn Center for Parallel Computing (PC2); 2025. doi:<a href=\"https://doi.org/10.48550/ARXIV.2512.07401\">10.48550/ARXIV.2512.07401</a>","apa":"Ehtesabi, S., Hossain, M., Kenter, T., Krawinkel, A., Ostermann, L., Plessl, C., Riebler, H., Rohde, S., Schade, R., Schwarz, M., Simon, J., Winnwa, N., Wiens, A., &#38; Wu, X. (2025). <i>Otus Supercomputer</i> (Vol. 1). Paderborn Center for Parallel Computing (PC2). <a href=\"https://doi.org/10.48550/ARXIV.2512.07401\">https://doi.org/10.48550/ARXIV.2512.07401</a>","short":"S. Ehtesabi, M. Hossain, T. Kenter, A. Krawinkel, L. Ostermann, C. Plessl, H. Riebler, S. Rohde, R. Schade, M. Schwarz, J. Simon, N. Winnwa, A. Wiens, X. Wu, Otus Supercomputer, Paderborn Center for Parallel Computing (PC2), Paderborn, 2025.","bibtex":"@book{Ehtesabi_Hossain_Kenter_Krawinkel_Ostermann_Plessl_Riebler_Rohde_Schade_Schwarz_et al._2025, place={Paderborn}, series={PC2 Tech­nic­al Re­port Series}, title={Otus Supercomputer}, volume={1}, DOI={<a href=\"https://doi.org/10.48550/ARXIV.2512.07401\">10.48550/ARXIV.2512.07401</a>}, publisher={Paderborn Center for Parallel Computing (PC2)}, author={Ehtesabi, Sadaf and Hossain, Manoar and Kenter, Tobias and Krawinkel, Andreas and Ostermann, Lukas and Plessl, Christian and Riebler, Heinrich and Rohde, Stefan and Schade, Robert and Schwarz, Michael and et al.}, year={2025}, collection={PC2 Tech­nic­al Re­port Series} }","mla":"Ehtesabi, Sadaf, et al. <i>Otus Supercomputer</i>. Paderborn Center for Parallel Computing (PC2), 2025, doi:<a href=\"https://doi.org/10.48550/ARXIV.2512.07401\">10.48550/ARXIV.2512.07401</a>."},"_id":"62981","department":[{"_id":"27"},{"_id":"518"}],"series_title":"PC2 Tech­nic­al Re­port Series","user_id":"23522","file_date_updated":"2026-03-25T11:50:30Z","type":"report","status":"public","publisher":"Paderborn Center for Parallel Computing (PC2)","date_created":"2025-12-09T09:11:04Z","title":"Otus Supercomputer","year":"2025","keyword":["Otus","Supercomputer","FPGA","PC2","Paderborn Center for Parallel Computing","Noctua 2","HPC"],"ddc":["004"],"language":[{"iso":"eng"}],"report_number":"PC2TR-2025-1","abstract":[{"lang":"eng","text":"Otus is a high-performance computing cluster that was launched in 2025 and is operated by the Paderborn Center for Parallel Computing (PC2) at Paderborn University in Germany. The system is part of the National High Performance Computing (NHR) initiative. Otus complements the previous supercomputer Noctua 2, offering approximately twice the computing power while retaining the three node types that were characteristic of Noctua 2: 1) CPU compute nodes with different memory capacities, 2) high-end GPU nodes, and 3) HPC-grade FPGA nodes. On the Top500 list, which ranks the 500 most powerful supercomputers in the world, Otus is in position 164 with the CPU partition and in position 255 with the GPU partition (June 2025). On the Green500 list, ranking the 500 most energy-efficient supercomputers in the world, Otus is in position 5 with the GPU partition (June 2025).\r\n\r\n\r\nThis article provides a comprehensive overview of the system in terms of its hardware, software, system integration, and its overall integration into the data center building to ensure energy-efficient operation. The article aims to provide unique insights for scientists using the system and for other centers operating HPC clusters. The article will be continuously updated to reflect the latest system setup and measurements. "}],"file":[{"relation":"main_file","content_type":"application/pdf","file_size":4535595,"file_name":"2512.07401v1.pdf","file_id":"62982","access_level":"open_access","date_updated":"2026-03-25T11:50:30Z","creator":"deffel","date_created":"2025-12-09T09:19:12Z"}]},{"title":"Noctua 2 Supercomputer","date_created":"2024-04-26T07:39:41Z","year":"2024","language":[{"iso":"eng"}],"ddc":["004"],"keyword":["Noctua 2","Supercomputer","FPGA","PC2","Paderborn Center for Parallel Computing"],"file":[{"file_size":3825480,"file_id":"53664","file_name":"Noctua2_Supercomputer.pdf","access_level":"open_access","date_updated":"2024-04-26T08:35:17Z","creator":"deffel","date_created":"2024-04-26T07:30:20Z","relation":"main_file","content_type":"application/pdf"}],"abstract":[{"text":"Noctua 2 is a supercomputer operated at the Paderborn Center for Parallel Computing (PC2) at Paderborn University in Germany. Noctua 2 was inaugurated in 2022 and is an Atos BullSequana XH2000 system. It consists mainly of three node types: 1) CPU Compute nodes with AMD EPYC processors in different main memory configurations, 2) GPU nodes with NVIDIA A100 GPUs, and 3) FPGA nodes with Xilinx Alveo U280 and Intel Stratix 10 FPGA cards. While CPUs and GPUs are known off-the-shelf components in HPC systems, the operation of a large number of FPGA cards from different vendors and a dedicated FPGA-to-FPGA network are unique characteristics of Noctua 2. This paper describes in detail the overall setup of Noctua 2 and gives insights into the operation of the cluster from a hardware, software and facility perspective.","lang":"eng"}],"publication":"Journal of large-scale research facilities","doi":"10.17815/jlsrf-8-187 ","author":[{"last_name":"Bauer","full_name":"Bauer, Carsten","id":"90082","first_name":"Carsten"},{"last_name":"Kenter","id":"3145","full_name":"Kenter, Tobias","first_name":"Tobias"},{"id":"24135","full_name":"Lass, Michael","last_name":"Lass","orcid":"0000-0002-5708-7632","first_name":"Michael"},{"first_name":"Lukas","last_name":"Mazur","orcid":" 0000-0001-6304-7082","full_name":"Mazur, Lukas","id":"90492"},{"first_name":"Marius","full_name":"Meyer, Marius","id":"40778","last_name":"Meyer"},{"full_name":"Nitsche, Holger","id":"15272","last_name":"Nitsche","first_name":"Holger"},{"first_name":"Heinrich","last_name":"Riebler","full_name":"Riebler, Heinrich","id":"8961"},{"first_name":"Robert","id":"75963","full_name":"Schade, Robert","orcid":"0000-0002-6268-5397","last_name":"Schade"},{"id":"5312","full_name":"Schwarz, Michael","last_name":"Schwarz","first_name":"Michael"},{"full_name":"Winnwa, Nils","id":"61189","last_name":"Winnwa","first_name":"Nils"},{"orcid":"0000-0003-1764-9773","last_name":"Wiens","id":"23522","full_name":"Wiens, Alex","first_name":"Alex"},{"full_name":"Wu, Xin","id":"77439","last_name":"Wu","first_name":"Xin"},{"first_name":"Christian","last_name":"Plessl","orcid":"0000-0001-5728-9982","id":"16153","full_name":"Plessl, Christian"},{"full_name":"Simon, Jens","id":"15273","last_name":"Simon","first_name":"Jens"}],"volume":9,"oa":"1","date_updated":"2024-04-26T08:44:30Z","citation":{"apa":"Bauer, C., Kenter, T., Lass, M., Mazur, L., Meyer, M., Nitsche, H., Riebler, H., Schade, R., Schwarz, M., Winnwa, N., Wiens, A., Wu, X., Plessl, C., &#38; Simon, J. (2024). Noctua 2 Supercomputer. <i>Journal of Large-Scale Research Facilities</i>, <i>9</i>. <a href=\"https://doi.org/10.17815/jlsrf-8-187 \">https://doi.org/10.17815/jlsrf-8-187 </a>","bibtex":"@article{Bauer_Kenter_Lass_Mazur_Meyer_Nitsche_Riebler_Schade_Schwarz_Winnwa_et al._2024, title={Noctua 2 Supercomputer}, volume={9}, DOI={<a href=\"https://doi.org/10.17815/jlsrf-8-187 \">10.17815/jlsrf-8-187 </a>}, journal={Journal of large-scale research facilities}, author={Bauer, Carsten and Kenter, Tobias and Lass, Michael and Mazur, Lukas and Meyer, Marius and Nitsche, Holger and Riebler, Heinrich and Schade, Robert and Schwarz, Michael and Winnwa, Nils and et al.}, year={2024} }","mla":"Bauer, Carsten, et al. “Noctua 2 Supercomputer.” <i>Journal of Large-Scale Research Facilities</i>, vol. 9, 2024, doi:<a href=\"https://doi.org/10.17815/jlsrf-8-187 \">10.17815/jlsrf-8-187 </a>.","short":"C. Bauer, T. Kenter, M. Lass, L. Mazur, M. Meyer, H. Nitsche, H. Riebler, R. Schade, M. Schwarz, N. Winnwa, A. Wiens, X. Wu, C. Plessl, J. Simon, Journal of Large-Scale Research Facilities 9 (2024).","ieee":"C. Bauer <i>et al.</i>, “Noctua 2 Supercomputer,” <i>Journal of large-scale research facilities</i>, vol. 9, 2024, doi: <a href=\"https://doi.org/10.17815/jlsrf-8-187 \">10.17815/jlsrf-8-187 </a>.","chicago":"Bauer, Carsten, Tobias Kenter, Michael Lass, Lukas Mazur, Marius Meyer, Holger Nitsche, Heinrich Riebler, et al. “Noctua 2 Supercomputer.” <i>Journal of Large-Scale Research Facilities</i> 9 (2024). <a href=\"https://doi.org/10.17815/jlsrf-8-187 \">https://doi.org/10.17815/jlsrf-8-187 </a>.","ama":"Bauer C, Kenter T, Lass M, et al. Noctua 2 Supercomputer. <i>Journal of large-scale research facilities</i>. 2024;9. doi:<a href=\"https://doi.org/10.17815/jlsrf-8-187 \">10.17815/jlsrf-8-187 </a>"},"intvolume":"         9","publication_status":"published","has_accepted_license":"1","file_date_updated":"2024-04-26T08:35:17Z","article_type":"original","user_id":"8961","department":[{"_id":"27"},{"_id":"518"}],"project":[{"name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing","_id":"52"}],"_id":"53663","status":"public","type":"journal_article"},{"ddc":["550"],"keyword":["Energy potential estimation","Photovoltaic","Solar radiation","Temperature measurement","Satellite data","Meteonorm","MERRA-2","DWD"],"language":[{"iso":"eng"}],"publication":"Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC 2021)","abstract":[{"text":"Access to precise meteorological data is crucial to be able to plan and install renewable energy systems \r\nsuch as solar power plants and wind farms. In case of solar energy, knowledge of local irradiance and air temperature \r\nvalues is very important. For this, various methods can be used such as installing local weather stations or using \r\nmeteorological data from different organizations such as Meteonorm or official Deutscher Wetterdienst (DWD). An \r\nalternative is to use satellite reanalysis datasets provided by organizations like the National Aeronautics and Space \r\nAdministration (NASA) and European Centre for Medium-Range Weather Forecasts (ECMWF). In this paper the \r\n“Modern-Era Retrospective analysis for Research and Applications” dataset version 2 (MERRA-2) will be presented, \r\nand its performance will be evaluated by comparing it to locally measured datasets provided by Meteonorm and DWD. \r\nThe analysis shows very high correlation between MERRA-2 and local measurements (correlation coefficients of 0.99) \r\nfor monthly global irradiance and air temperature values. The results prove the suitability of MERRA-2 data for \r\napplications requiring long historical data. Moreover, availability of MERRA-2 for the whole world with an acceptable \r\nresolution makes it a very valuable dataset.","lang":"eng"}],"file":[{"content_type":"application/pdf","success":1,"relation":"main_file","date_updated":"2022-01-06T13:26:47Z","date_created":"2022-01-06T13:26:47Z","creator":"krauter","file_size":2475972,"file_id":"29176","access_level":"closed","file_name":"Khatibi Krauter - MERRA 2 vs Meteonorm - EUPVSEC 2021.pdf"}],"date_created":"2021-09-16T10:20:41Z","title":"Comparison and Validation of Irradiance Data: Satellite Meteorological Dataset MERRA-2 vs. Meteonorm and German Weather Service (DWD)","quality_controlled":"1","year":"2021","_id":"24551","user_id":"28836","department":[{"_id":"53"}],"file_date_updated":"2022-01-06T13:26:47Z","type":"conference","status":"public","date_updated":"2022-01-06T13:29:51Z","author":[{"id":"43538","full_name":"Khatibi, Arash","last_name":"Khatibi","first_name":"Arash"},{"last_name":"Krauter","orcid":"0000-0002-3594-260X","full_name":"Krauter, Stefan","id":"28836","first_name":"Stefan"}],"doi":"10.4229/EUPVSEC20212021-5BV.4.11","conference":{"end_date":"2021-09-10","name":"38th European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC 2021)","start_date":"2021-09-06"},"publication_status":"published","publication_identifier":{"isbn":["3-936338-78-7"]},"has_accepted_license":"1","citation":{"ieee":"A. Khatibi and S. Krauter, “Comparison and Validation of Irradiance Data: Satellite Meteorological Dataset MERRA-2 vs. Meteonorm and German Weather Service (DWD),” in <i>Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC 2021)</i>, 2021, pp. 1141–1147, doi: <a href=\"https://doi.org/10.4229/EUPVSEC20212021-5BV.4.11\">10.4229/EUPVSEC20212021-5BV.4.11</a>.","chicago":"Khatibi, Arash, and Stefan Krauter. “Comparison and Validation of Irradiance Data: Satellite Meteorological Dataset MERRA-2 vs. Meteonorm and German Weather Service (DWD).” In <i>Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC 2021)</i>, 1141–47, 2021. <a href=\"https://doi.org/10.4229/EUPVSEC20212021-5BV.4.11\">https://doi.org/10.4229/EUPVSEC20212021-5BV.4.11</a>.","ama":"Khatibi A, Krauter S. Comparison and Validation of Irradiance Data: Satellite Meteorological Dataset MERRA-2 vs. Meteonorm and German Weather Service (DWD). In: <i>Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC 2021)</i>. ; 2021:1141-1147. doi:<a href=\"https://doi.org/10.4229/EUPVSEC20212021-5BV.4.11\">10.4229/EUPVSEC20212021-5BV.4.11</a>","apa":"Khatibi, A., &#38; Krauter, S. (2021). Comparison and Validation of Irradiance Data: Satellite Meteorological Dataset MERRA-2 vs. Meteonorm and German Weather Service (DWD). <i>Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC 2021)</i>, 1141–1147. <a href=\"https://doi.org/10.4229/EUPVSEC20212021-5BV.4.11\">https://doi.org/10.4229/EUPVSEC20212021-5BV.4.11</a>","mla":"Khatibi, Arash, and Stefan Krauter. “Comparison and Validation of Irradiance Data: Satellite Meteorological Dataset MERRA-2 vs. Meteonorm and German Weather Service (DWD).” <i>Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC 2021)</i>, 2021, pp. 1141–47, doi:<a href=\"https://doi.org/10.4229/EUPVSEC20212021-5BV.4.11\">10.4229/EUPVSEC20212021-5BV.4.11</a>.","short":"A. Khatibi, S. Krauter, in: Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC 2021), 2021, pp. 1141–1147.","bibtex":"@inproceedings{Khatibi_Krauter_2021, title={Comparison and Validation of Irradiance Data: Satellite Meteorological Dataset MERRA-2 vs. Meteonorm and German Weather Service (DWD)}, DOI={<a href=\"https://doi.org/10.4229/EUPVSEC20212021-5BV.4.11\">10.4229/EUPVSEC20212021-5BV.4.11</a>}, booktitle={Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC 2021)}, author={Khatibi, Arash and Krauter, Stefan}, year={2021}, pages={1141–1147} }"},"page":"1141 - 1147"},{"abstract":[{"lang":"eng","text":"<jats:p>Fast-growing energy demand of the world makes the researchers focus on finding new energy sources or optimizing already-developed approaches. For an efficient use of solar and wind energy in an energy system, correct design and sizing of a power system is of high importance and improving or optimizing the process of data obtaining for this purpose leads to higher performance and lower cost per unit of energy. It is essential to have the most precise possible estimation of solar and wind energy potential and other local weather parameters in order to fully feed the demand and avoid extra costs. There are various methods for obtaining local data, such as local measurements, official organizational data, satellite obtained, and reanalysis data. In this paper, the Modern-Era Retrospective analysis for Research and Applications dataset version 2 (MERRA-2) dataset provided by NASA is introduced and its performance is evaluated by comparison to various locally measured datasets offered by meteorological institutions such as Meteonorm and Deutscher Wetterdienst (DWD, or Germany’s National Meteorological Service) around the world. After comparison, correlation coefficients from 0.95 to 0.99 are observed for monthly global horizontal irradiance values. In the case of air temperature, correlation coefficients of 0.99 and for wind speed from 0.81 to 0.99 are observed. High correlation with ground measurements and relatively low errors are confirmed, especially for irradiance and temperature values, that makes MERRA-2 a valuable dataset, considering its world coverage and availability.</jats:p>"}],"file":[{"file_size":3837152,"file_name":"energies-14-00882 Khatibi Krauter MERRA 2.pdf","access_level":"closed","file_id":"29177","date_updated":"2022-01-06T13:33:09Z","creator":"krauter","date_created":"2022-01-06T13:33:09Z","success":1,"relation":"main_file","content_type":"application/pdf"}],"publication":"Energies","ddc":["620"],"keyword":["Solar irradiance","MERRA 2","Meteonorm","DWD"],"language":[{"iso":"eng"}],"year":"2021","quality_controlled":"1","issue":"4","title":"Validation and Performance of Satellite Meteorological Dataset MERRA-2 for Solar and Wind Applications","publisher":"MDPI","date_created":"2021-02-23T10:18:05Z","status":"public","type":"journal_article","article_number":"882","article_type":"original","file_date_updated":"2022-01-06T13:33:09Z","_id":"21265","user_id":"28836","department":[{"_id":"53"}],"citation":{"ama":"Khatibi A, Krauter S. Validation and Performance of Satellite Meteorological Dataset MERRA-2 for Solar and Wind Applications. <i>Energies</i>. 2021;14(4). doi:<a href=\"https://doi.org/10.3390/en14040882\">10.3390/en14040882</a>","ieee":"A. Khatibi and S. Krauter, “Validation and Performance of Satellite Meteorological Dataset MERRA-2 for Solar and Wind Applications,” <i>Energies</i>, vol. 14, no. 4, Art. no. 882, 2021, doi: <a href=\"https://doi.org/10.3390/en14040882\">10.3390/en14040882</a>.","chicago":"Khatibi, Arash, and Stefan Krauter. “Validation and Performance of Satellite Meteorological Dataset MERRA-2 for Solar and Wind Applications.” <i>Energies</i> 14, no. 4 (2021). <a href=\"https://doi.org/10.3390/en14040882\">https://doi.org/10.3390/en14040882</a>.","apa":"Khatibi, A., &#38; Krauter, S. (2021). Validation and Performance of Satellite Meteorological Dataset MERRA-2 for Solar and Wind Applications. <i>Energies</i>, <i>14</i>(4), Article 882. <a href=\"https://doi.org/10.3390/en14040882\">https://doi.org/10.3390/en14040882</a>","bibtex":"@article{Khatibi_Krauter_2021, title={Validation and Performance of Satellite Meteorological Dataset MERRA-2 for Solar and Wind Applications}, volume={14}, DOI={<a href=\"https://doi.org/10.3390/en14040882\">10.3390/en14040882</a>}, number={4882}, journal={Energies}, publisher={MDPI}, author={Khatibi, Arash and Krauter, Stefan}, year={2021} }","mla":"Khatibi, Arash, and Stefan Krauter. “Validation and Performance of Satellite Meteorological Dataset MERRA-2 for Solar and Wind Applications.” <i>Energies</i>, vol. 14, no. 4, 882, MDPI, 2021, doi:<a href=\"https://doi.org/10.3390/en14040882\">10.3390/en14040882</a>.","short":"A. Khatibi, S. Krauter, Energies 14 (2021)."},"intvolume":"        14","publication_status":"published","publication_identifier":{"issn":["1996-1073"]},"has_accepted_license":"1","main_file_link":[{"open_access":"1","url":"https://www.mdpi.com/1996-1073/14/4/882/htm"}],"doi":"10.3390/en14040882","date_updated":"2022-01-06T13:37:34Z","oa":"1","author":[{"first_name":"Arash","last_name":"Khatibi","id":"43538","full_name":"Khatibi, Arash"},{"first_name":"Stefan","orcid":"0000-0002-3594-260X","last_name":"Krauter","full_name":"Krauter, Stefan","id":"28836"}],"volume":14},{"status":"public","file":[{"date_updated":"2021-11-18T10:52:58Z","creator":"jludwig","date_created":"2021-11-18T10:52:58Z","file_size":160577,"file_name":"abstract_EAC2021_UPB.pdf","file_id":"27552","access_level":"closed","content_type":"application/pdf","success":1,"relation":"main_file"}],"publication":"Book of abstracts for the 2021 European Aerosol Conference","type":"conference_abstract","keyword":["aerosol spreading","SARS-CoV-2","indoor air filtration"],"ddc":["660"],"language":[{"iso":"eng"}],"file_date_updated":"2021-11-18T10:52:58Z","_id":"27551","department":[{"_id":"150"},{"_id":"9"}],"user_id":"45788","year":"2021","corporate_editor":["The Aerosol Society"],"citation":{"chicago":"Ludwig, Janis, Carsten Kykal, and Hans-Joachim Schmid. “Assessing Spreading and Removal of Virus Laden Aerosols in Different Settings Using an Aerosol Method (Oral Presentation).” In <i>Book of Abstracts for the 2021 European Aerosol Conference</i>, edited by The Aerosol Society, 2021.","ieee":"J. Ludwig, C. Kykal, and H.-J. Schmid, “Assessing spreading and removal of virus laden aerosols in different settings using an aerosol method (oral presentation),” in <i>Book of abstracts for the 2021 European Aerosol Conference</i>, 2021.","ama":"Ludwig J, Kykal C, Schmid H-J. Assessing spreading and removal of virus laden aerosols in different settings using an aerosol method (oral presentation). In: The Aerosol Society, ed. <i>Book of Abstracts for the 2021 European Aerosol Conference</i>. ; 2021.","mla":"Ludwig, Janis, et al. “Assessing Spreading and Removal of Virus Laden Aerosols in Different Settings Using an Aerosol Method (Oral Presentation).” <i>Book of Abstracts for the 2021 European Aerosol Conference</i>, edited by The Aerosol Society, 2021.","bibtex":"@inproceedings{Ludwig_Kykal_Schmid_2021, title={Assessing spreading and removal of virus laden aerosols in different settings using an aerosol method (oral presentation)}, booktitle={Book of abstracts for the 2021 European Aerosol Conference}, author={Ludwig, Janis and Kykal, Carsten and Schmid, Hans-Joachim}, editor={The Aerosol Society}, year={2021} }","short":"J. Ludwig, C. Kykal, H.-J. Schmid, in: The Aerosol Society (Ed.), Book of Abstracts for the 2021 European Aerosol Conference, 2021.","apa":"Ludwig, J., Kykal, C., &#38; Schmid, H.-J. (2021). Assessing spreading and removal of virus laden aerosols in different settings using an aerosol method (oral presentation). In The Aerosol Society (Ed.), <i>Book of abstracts for the 2021 European Aerosol Conference</i>."},"has_accepted_license":"1","title":"Assessing spreading and removal of virus laden aerosols in different settings using an aerosol method (oral presentation)","conference":{"end_date":"2021-09-03","name":"European Aerosol Conference","start_date":"2021-08-30"},"date_updated":"2025-09-18T08:45:49Z","date_created":"2021-11-18T10:53:35Z","author":[{"first_name":"Janis","orcid":"0009-0001-1348-496X","last_name":"Ludwig","full_name":"Ludwig, Janis","id":"45788"},{"full_name":"Kykal, Carsten","last_name":"Kykal","first_name":"Carsten"},{"orcid":"000-0001-8590-1921","last_name":"Schmid","id":"464","full_name":"Schmid, Hans-Joachim","first_name":"Hans-Joachim"}]},{"publication":"43rd International Symposium on Mathematical Foundations  of Computer Science (MFCS 2018)","abstract":[{"lang":"eng","text":"The polynomial-time hierarchy (PH) has proven to be a powerful tool for providing separations in computational complexity theory (modulo standard conjectures such as PH does not collapse). Here, we study whether two quantum generalizations of PH can similarly prove separations in the quantum setting. The first generalization, QCPH, uses classical proofs, and the second, QPH, uses quantum proofs. For the former, we show quantum variants of the Karp-Lipton theorem and Toda's theorem. For the latter, we place its third level, Q Sigma_3, into NEXP using the Ellipsoid Method for efficiently solving semidefinite programs. These results yield two implications for QMA(2), the variant of Quantum Merlin-Arthur (QMA) with two unentangled proofs, a complexity class whose characterization has proven difficult. First, if QCPH=QPH (i.e., alternating quantifiers are sufficiently powerful so as to make classical and quantum proofs \"equivalent\"), then QMA(2) is in the Counting Hierarchy (specifically, in P^{PP^{PP}}). Second, unless QMA(2)= Q Sigma_3 (i.e., alternating quantifiers do not help in the presence of \"unentanglement\"), QMA(2) is strictly contained in NEXP."}],"external_id":{"arxiv":["1805.11139"]},"language":[{"iso":"eng"}],"keyword":["Complexity Theory","Quantum Computing","Polynomial Hierarchy","Semidefinite Programming","QMA(2)","Quantum Complexity"],"year":"2018","date_created":"2019-03-01T11:29:44Z","publisher":"Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik","title":"Quantum Generalizations of the Polynomial Hierarchy with Applications to QMA(2)","type":"conference","status":"public","editor":[{"full_name":"Potapov, Igor","last_name":"Potapov","first_name":"Igor"},{"first_name":"Paul","last_name":"Spirakis","full_name":"Spirakis, Paul"},{"last_name":"Worrell","full_name":"Worrell, James","first_name":"James"}],"department":[{"_id":"623"},{"_id":"7"}],"user_id":"71541","series_title":"Leibniz International Proceedings in Informatics (LIPIcs)","_id":"8161","publication_identifier":{"unknown":["978-3-95977-086-6"]},"publication_status":"published","intvolume":"       117","page":"58:1-58:16","citation":{"apa":"Gharibian, S., Santha, M., Sikora, J., Sundaram, A., &#38; Yirka, J. (2018). Quantum Generalizations of the Polynomial Hierarchy with Applications to QMA(2). In I. Potapov, P. Spirakis, &#38; J. Worrell (Eds.), <i>43rd International Symposium on Mathematical Foundations  of Computer Science (MFCS 2018)</i> (Vol. 117, p. 58:1-58:16). Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik. <a href=\"https://doi.org/10.4230/LIPIcs.MFCS.2018.58\">https://doi.org/10.4230/LIPIcs.MFCS.2018.58</a>","bibtex":"@inproceedings{Gharibian_Santha_Sikora_Sundaram_Yirka_2018, place={Dagstuhl, Germany}, series={Leibniz International Proceedings in Informatics (LIPIcs)}, title={Quantum Generalizations of the Polynomial Hierarchy with Applications to QMA(2)}, volume={117}, DOI={<a href=\"https://doi.org/10.4230/LIPIcs.MFCS.2018.58\">10.4230/LIPIcs.MFCS.2018.58</a>}, booktitle={43rd International Symposium on Mathematical Foundations  of Computer Science (MFCS 2018)}, publisher={Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik}, author={Gharibian, Sevag and Santha, Miklos and Sikora, Jamie and Sundaram, Aarthi and Yirka, Justin}, editor={Potapov, Igor and Spirakis, Paul and Worrell, James}, year={2018}, pages={58:1-58:16}, collection={Leibniz International Proceedings in Informatics (LIPIcs)} }","short":"S. Gharibian, M. Santha, J. Sikora, A. Sundaram, J. Yirka, in: I. Potapov, P. Spirakis, J. Worrell (Eds.), 43rd International Symposium on Mathematical Foundations  of Computer Science (MFCS 2018), Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, Dagstuhl, Germany, 2018, p. 58:1-58:16.","mla":"Gharibian, Sevag, et al. “Quantum Generalizations of the Polynomial Hierarchy with Applications to QMA(2).” <i>43rd International Symposium on Mathematical Foundations  of Computer Science (MFCS 2018)</i>, edited by Igor Potapov et al., vol. 117, Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, 2018, p. 58:1-58:16, doi:<a href=\"https://doi.org/10.4230/LIPIcs.MFCS.2018.58\">10.4230/LIPIcs.MFCS.2018.58</a>.","ieee":"S. Gharibian, M. Santha, J. Sikora, A. Sundaram, and J. Yirka, “Quantum Generalizations of the Polynomial Hierarchy with Applications to QMA(2),” in <i>43rd International Symposium on Mathematical Foundations  of Computer Science (MFCS 2018)</i>, Liverpool, UK, 2018, vol. 117, p. 58:1-58:16, doi: <a href=\"https://doi.org/10.4230/LIPIcs.MFCS.2018.58\">10.4230/LIPIcs.MFCS.2018.58</a>.","chicago":"Gharibian, Sevag, Miklos Santha, Jamie Sikora, Aarthi Sundaram, and Justin Yirka. “Quantum Generalizations of the Polynomial Hierarchy with Applications to QMA(2).” In <i>43rd International Symposium on Mathematical Foundations  of Computer Science (MFCS 2018)</i>, edited by Igor Potapov, Paul Spirakis, and James Worrell, 117:58:1-58:16. Leibniz International Proceedings in Informatics (LIPIcs). Dagstuhl, Germany: Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, 2018. <a href=\"https://doi.org/10.4230/LIPIcs.MFCS.2018.58\">https://doi.org/10.4230/LIPIcs.MFCS.2018.58</a>.","ama":"Gharibian S, Santha M, Sikora J, Sundaram A, Yirka J. Quantum Generalizations of the Polynomial Hierarchy with Applications to QMA(2). In: Potapov I, Spirakis P, Worrell J, eds. <i>43rd International Symposium on Mathematical Foundations  of Computer Science (MFCS 2018)</i>. Vol 117. Leibniz International Proceedings in Informatics (LIPIcs). Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik; 2018:58:1-58:16. doi:<a href=\"https://doi.org/10.4230/LIPIcs.MFCS.2018.58\">10.4230/LIPIcs.MFCS.2018.58</a>"},"place":"Dagstuhl, Germany","volume":117,"author":[{"first_name":"Sevag","id":"71541","full_name":"Gharibian, Sevag","orcid":"0000-0002-9992-3379","last_name":"Gharibian"},{"full_name":"Santha, Miklos","last_name":"Santha","first_name":"Miklos"},{"last_name":"Sikora","full_name":"Sikora, Jamie","first_name":"Jamie"},{"last_name":"Sundaram","full_name":"Sundaram, Aarthi","first_name":"Aarthi"},{"first_name":"Justin","last_name":"Yirka","full_name":"Yirka, Justin"}],"oa":"1","date_updated":"2023-02-28T11:01:03Z","doi":"10.4230/LIPIcs.MFCS.2018.58","conference":{"location":"Liverpool, UK","name":"43rd International Symposium on Mathematical Foundations  of Computer Science (MFCS 2018)"},"main_file_link":[{"url":"http://drops.dagstuhl.de/opus/frontdoor.php?source_opus=9640","open_access":"1"}]},{"doi":"10.4230/LIPIcs.TQC.2017.2","conference":{"name":"12th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2017)","location":"Paris, France"},"main_file_link":[{"open_access":"1","url":"http://drops.dagstuhl.de/opus/frontdoor.php?source_opus=8577"}],"volume":73,"author":[{"first_name":"Sevag","full_name":"Gharibian, Sevag","id":"71541","orcid":"0000-0002-9992-3379","last_name":"Gharibian"},{"first_name":"Justin","full_name":"Yirka, Justin","last_name":"Yirka"}],"date_updated":"2023-02-28T11:00:48Z","oa":"1","page":"2:1-2:17","intvolume":"        73","citation":{"ieee":"S. Gharibian and J. Yirka, “The Complexity of Simulating Local Measurements on Quantum Systems,” in <i>12th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2017)</i>, Paris, France, 2018, vol. 73, p. 2:1-2:17, doi: <a href=\"https://doi.org/10.4230/LIPIcs.TQC.2017.2\">10.4230/LIPIcs.TQC.2017.2</a>.","chicago":"Gharibian, Sevag, and Justin Yirka. “The Complexity of Simulating Local Measurements on Quantum Systems.” In <i>12th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2017)</i>, edited by Mark Wilde, 73:2:1-2:17. Leibniz International Proceedings in Informatics (LIPIcs). Dagstuhl, Germany: Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, 2018. <a href=\"https://doi.org/10.4230/LIPIcs.TQC.2017.2\">https://doi.org/10.4230/LIPIcs.TQC.2017.2</a>.","ama":"Gharibian S, Yirka J. The Complexity of Simulating Local Measurements on Quantum Systems. In: Wilde M, ed. <i>12th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2017)</i>. Vol 73. Leibniz International Proceedings in Informatics (LIPIcs). Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik; 2018:2:1-2:17. doi:<a href=\"https://doi.org/10.4230/LIPIcs.TQC.2017.2\">10.4230/LIPIcs.TQC.2017.2</a>","short":"S. Gharibian, J. Yirka, in: M. Wilde (Ed.), 12th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2017), Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, Dagstuhl, Germany, 2018, p. 2:1-2:17.","bibtex":"@inproceedings{Gharibian_Yirka_2018, place={Dagstuhl, Germany}, series={Leibniz International Proceedings in Informatics (LIPIcs)}, title={The Complexity of Simulating Local Measurements on Quantum Systems}, volume={73}, DOI={<a href=\"https://doi.org/10.4230/LIPIcs.TQC.2017.2\">10.4230/LIPIcs.TQC.2017.2</a>}, booktitle={12th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2017)}, publisher={Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik}, author={Gharibian, Sevag and Yirka, Justin}, editor={Wilde, Mark}, year={2018}, pages={2:1-2:17}, collection={Leibniz International Proceedings in Informatics (LIPIcs)} }","mla":"Gharibian, Sevag, and Justin Yirka. “The Complexity of Simulating Local Measurements on Quantum Systems.” <i>12th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2017)</i>, edited by Mark Wilde, vol. 73, Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, 2018, p. 2:1-2:17, doi:<a href=\"https://doi.org/10.4230/LIPIcs.TQC.2017.2\">10.4230/LIPIcs.TQC.2017.2</a>.","apa":"Gharibian, S., &#38; Yirka, J. (2018). The Complexity of Simulating Local Measurements on Quantum Systems. In M. Wilde (Ed.), <i>12th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2017)</i> (Vol. 73, p. 2:1-2:17). Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik. <a href=\"https://doi.org/10.4230/LIPIcs.TQC.2017.2\">https://doi.org/10.4230/LIPIcs.TQC.2017.2</a>"},"place":"Dagstuhl, Germany","publication_identifier":{"unknown":["978-3-95977-034-7"]},"publication_status":"published","department":[{"_id":"623"},{"_id":"7"}],"series_title":"Leibniz International Proceedings in Informatics (LIPIcs)","user_id":"71541","_id":"8160","status":"public","editor":[{"last_name":"Wilde","full_name":"Wilde, Mark","first_name":"Mark"}],"type":"conference","title":"The Complexity of Simulating Local Measurements on Quantum Systems","date_created":"2019-03-01T11:25:27Z","publisher":"Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik","year":"2018","language":[{"iso":"eng"}],"keyword":["Complexity theory","Quantum Merlin Arthur (QMA)","local Hamiltonian","local measurement","spectral gap"],"external_id":{"arxiv":["1606.05626"]},"abstract":[{"text":"An important task in quantum physics is the estimation of local quantities for ground states of local Hamiltonians. Recently, Ambainis defined the complexity class P^QMA[log], and motivated its study by showing that the physical task of estimating the expectation value of a local observable against the ground state of a local Hamiltonian is P^QMA[log]-complete. In this paper, we continue the study of P^QMA[log], obtaining the following results. The P^QMA[log]-completeness result of Ambainis requires O(log n)-local observ- ables and Hamiltonians. We show that simulating even a single qubit measurement on ground states of 5-local Hamiltonians is P^QMA[log]-complete, resolving an open question of Ambainis. We formalize the complexity theoretic study of estimating two-point correlation functions against ground states, and show that this task is similarly P^QMA[log]-complete. P^QMA[log] is thought of as \"slightly harder\" than QMA. We justify this formally by exploiting the hierarchical voting technique of Beigel, Hemachandra, and Wechsung to show P^QMA[log] \\subseteq PP. This improves the containment QMA \\subseteq PP from Kitaev and Watrous. A central theme of this work is the subtlety involved in the study of oracle classes in which the oracle solves a promise problem. In this vein, we identify a flaw in Ambainis' prior work regarding a P^UQMA[log]-hardness proof for estimating spectral gaps of local Hamiltonians. By introducing a \"query validation\" technique, we build on his prior work to obtain P^UQMA[log]-hardness for estimating spectral gaps under polynomial-time Turing reductions.","lang":"eng"}],"publication":"12th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2017)"},{"type":"conference","editor":[{"first_name":"Ran","last_name":"Raz","full_name":"Raz, Ran"}],"status":"public","_id":"8159","series_title":"Leibniz International Proceedings in Informatics (LIPIcs)","user_id":"71541","department":[{"_id":"623"},{"_id":"7"}],"extern":"1","publication_status":"published","publication_identifier":{"isbn":["978-3-95977-008-8"]},"place":"Dagstuhl, Germany","citation":{"ama":"de Beaudrap N, Gharibian S. A Linear Time Algorithm for Quantum 2-SAT. In: Raz R, ed. <i>Proceedings of the 31st Conference on Computational Complexity (CCC 2016)</i>. Vol 50. Leibniz International Proceedings in Informatics (LIPIcs). Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik; 2016:27:1-17:21. doi:<a href=\"https://doi.org/10.4230/LIPIcs.CCC.2016.27\">10.4230/LIPIcs.CCC.2016.27</a>","ieee":"N. de Beaudrap and S. Gharibian, “A Linear Time Algorithm for Quantum 2-SAT,” in <i>Proceedings of the 31st Conference on Computational Complexity (CCC 2016)</i>, Tokyo, Japan, 2016, vol. 50, p. 27:1–17:21, doi: <a href=\"https://doi.org/10.4230/LIPIcs.CCC.2016.27\">10.4230/LIPIcs.CCC.2016.27</a>.","chicago":"Beaudrap, Niel de, and Sevag Gharibian. “A Linear Time Algorithm for Quantum 2-SAT.” In <i>Proceedings of the 31st Conference on Computational Complexity (CCC 2016)</i>, edited by Ran Raz, 50:27:1-17:21. Leibniz International Proceedings in Informatics (LIPIcs). Dagstuhl, Germany: Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, 2016. <a href=\"https://doi.org/10.4230/LIPIcs.CCC.2016.27\">https://doi.org/10.4230/LIPIcs.CCC.2016.27</a>.","apa":"de Beaudrap, N., &#38; Gharibian, S. (2016). A Linear Time Algorithm for Quantum 2-SAT. In R. Raz (Ed.), <i>Proceedings of the 31st Conference on Computational Complexity (CCC 2016)</i> (Vol. 50, p. 27:1-17:21). Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik. <a href=\"https://doi.org/10.4230/LIPIcs.CCC.2016.27\">https://doi.org/10.4230/LIPIcs.CCC.2016.27</a>","mla":"de Beaudrap, Niel, and Sevag Gharibian. “A Linear Time Algorithm for Quantum 2-SAT.” <i>Proceedings of the 31st Conference on Computational Complexity (CCC 2016)</i>, edited by Ran Raz, vol. 50, Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, 2016, p. 27:1-17:21, doi:<a href=\"https://doi.org/10.4230/LIPIcs.CCC.2016.27\">10.4230/LIPIcs.CCC.2016.27</a>.","bibtex":"@inproceedings{de Beaudrap_Gharibian_2016, place={Dagstuhl, Germany}, series={Leibniz International Proceedings in Informatics (LIPIcs)}, title={A Linear Time Algorithm for Quantum 2-SAT}, volume={50}, DOI={<a href=\"https://doi.org/10.4230/LIPIcs.CCC.2016.27\">10.4230/LIPIcs.CCC.2016.27</a>}, booktitle={Proceedings of the 31st Conference on Computational Complexity (CCC 2016)}, publisher={Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik}, author={de Beaudrap, Niel and Gharibian, Sevag}, editor={Raz, Ran}, year={2016}, pages={27:1–17:21}, collection={Leibniz International Proceedings in Informatics (LIPIcs)} }","short":"N. de Beaudrap, S. Gharibian, in: R. Raz (Ed.), Proceedings of the 31st Conference on Computational Complexity (CCC 2016), Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, Dagstuhl, Germany, 2016, p. 27:1–17:21."},"page":"27:1-17:21","intvolume":"        50","oa":"1","date_updated":"2023-02-28T11:01:53Z","author":[{"last_name":"de Beaudrap","full_name":"de Beaudrap, Niel","first_name":"Niel"},{"id":"71541","full_name":"Gharibian, Sevag","last_name":"Gharibian","orcid":"0000-0002-9992-3379","first_name":"Sevag"}],"volume":50,"main_file_link":[{"open_access":"1","url":"http://drops.dagstuhl.de/opus/volltexte/2016/5836/"}],"doi":"10.4230/LIPIcs.CCC.2016.27","conference":{"location":"Tokyo, Japan","name":"31st Conference on Computational Complexity (CCC 2016)"},"publication":"Proceedings of the 31st Conference on Computational Complexity (CCC 2016)","abstract":[{"text":"The Boolean constraint satisfaction problem 3-SAT is arguably the canonical NP-complete problem. In contrast, 2-SAT can not only be decided in polynomial time, but in fact in deterministic linear time. In 2006, Bravyi proposed a physically motivated generalization of k-SAT to the quantum setting, defining the problem \"quantum k-SAT\". He showed that quantum 2-SAT is also solvable in polynomial time on a classical computer, in particular in deterministic time O(n^4), assuming unit-cost arithmetic over a field extension of the rational numbers, where n is number of variables. In this paper, we present an algorithm for quantum 2-SAT which runs in linear time, i.e. deterministic time O(n+m) for n and m the number of variables and clauses, respectively. Our approach exploits the transfer matrix techniques of Laumann et al. [QIC, 2010] used in the study of phase transitions for random quantum 2-SAT, and bears similarities with both the linear time 2-SAT algorithms of Even, Itai, and Shamir (based on backtracking) [SICOMP, 1976] and Aspvall, Plass, and Tarjan (based on strongly connected components) [IPL, 1979].","lang":"eng"}],"external_id":{"arxiv":["1508.07338"]},"keyword":["quantum 2-SAT","transfer matrix","strongly connected components","limited backtracking","local Hamiltonian"],"language":[{"iso":"eng"}],"year":"2016","publisher":"Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik","date_created":"2019-03-01T11:19:54Z","title":"A Linear Time Algorithm for Quantum 2-SAT"},{"user_id":"102979","department":[{"_id":"819"}],"_id":"48889","language":[{"iso":"eng"}],"keyword":["2-opt","90B06","Classification","Feature selection","MARS","TSP"],"type":"journal_article","publication":"Annals of Mathematics and Artificial Intelligence","status":"public","abstract":[{"lang":"eng","text":"Meta-heuristics are frequently used to tackle NP-hard combinatorial optimization problems. With this paper we contribute to the understanding of the success of 2-opt based local search algorithms for solving the traveling salesperson problem (TSP). Although 2-opt is widely used in practice, it is hard to understand its success from a theoretical perspective. We take a statistical approach and examine the features of TSP instances that make the problem either hard or easy to solve. As a measure of problem difficulty for 2-opt we use the approximation ratio that it achieves on a given instance. Our investigations point out important features that make TSP instances hard or easy to be approximated by 2-opt."}],"date_created":"2023-11-14T15:58:59Z","author":[{"full_name":"Mersmann, Olaf","last_name":"Mersmann","first_name":"Olaf"},{"last_name":"Bischl","full_name":"Bischl, Bernd","first_name":"Bernd"},{"first_name":"Heike","last_name":"Trautmann","full_name":"Trautmann, Heike"},{"full_name":"Wagner, Markus","last_name":"Wagner","first_name":"Markus"},{"id":"102979","full_name":"Bossek, Jakob","orcid":"0000-0002-4121-4668","last_name":"Bossek","first_name":"Jakob"},{"full_name":"Neumann, Frank","last_name":"Neumann","first_name":"Frank"}],"volume":69,"date_updated":"2023-12-13T10:50:41Z","doi":"10.1007/s10472-013-9341-2","title":"A Novel Feature-Based Approach to Characterize Algorithm Performance for the Traveling Salesperson Problem","issue":"2","publication_identifier":{"issn":["1012-2443"]},"citation":{"bibtex":"@article{Mersmann_Bischl_Trautmann_Wagner_Bossek_Neumann_2013, title={A Novel Feature-Based Approach to Characterize Algorithm Performance for the Traveling Salesperson Problem}, volume={69}, DOI={<a href=\"https://doi.org/10.1007/s10472-013-9341-2\">10.1007/s10472-013-9341-2</a>}, number={2}, journal={Annals of Mathematics and Artificial Intelligence}, author={Mersmann, Olaf and Bischl, Bernd and Trautmann, Heike and Wagner, Markus and Bossek, Jakob and Neumann, Frank}, year={2013}, pages={151–182} }","mla":"Mersmann, Olaf, et al. “A Novel Feature-Based Approach to Characterize Algorithm Performance for the Traveling Salesperson Problem.” <i>Annals of Mathematics and Artificial Intelligence</i>, vol. 69, no. 2, 2013, pp. 151–182, doi:<a href=\"https://doi.org/10.1007/s10472-013-9341-2\">10.1007/s10472-013-9341-2</a>.","short":"O. Mersmann, B. Bischl, H. Trautmann, M. Wagner, J. Bossek, F. Neumann, Annals of Mathematics and Artificial Intelligence 69 (2013) 151–182.","apa":"Mersmann, O., Bischl, B., Trautmann, H., Wagner, M., Bossek, J., &#38; Neumann, F. (2013). A Novel Feature-Based Approach to Characterize Algorithm Performance for the Traveling Salesperson Problem. <i>Annals of Mathematics and Artificial Intelligence</i>, <i>69</i>(2), 151–182. <a href=\"https://doi.org/10.1007/s10472-013-9341-2\">https://doi.org/10.1007/s10472-013-9341-2</a>","ama":"Mersmann O, Bischl B, Trautmann H, Wagner M, Bossek J, Neumann F. A Novel Feature-Based Approach to Characterize Algorithm Performance for the Traveling Salesperson Problem. <i>Annals of Mathematics and Artificial Intelligence</i>. 2013;69(2):151–182. doi:<a href=\"https://doi.org/10.1007/s10472-013-9341-2\">10.1007/s10472-013-9341-2</a>","chicago":"Mersmann, Olaf, Bernd Bischl, Heike Trautmann, Markus Wagner, Jakob Bossek, and Frank Neumann. “A Novel Feature-Based Approach to Characterize Algorithm Performance for the Traveling Salesperson Problem.” <i>Annals of Mathematics and Artificial Intelligence</i> 69, no. 2 (2013): 151–182. <a href=\"https://doi.org/10.1007/s10472-013-9341-2\">https://doi.org/10.1007/s10472-013-9341-2</a>.","ieee":"O. Mersmann, B. Bischl, H. Trautmann, M. Wagner, J. Bossek, and F. Neumann, “A Novel Feature-Based Approach to Characterize Algorithm Performance for the Traveling Salesperson Problem,” <i>Annals of Mathematics and Artificial Intelligence</i>, vol. 69, no. 2, pp. 151–182, 2013, doi: <a href=\"https://doi.org/10.1007/s10472-013-9341-2\">10.1007/s10472-013-9341-2</a>."},"page":"151–182","intvolume":"        69","year":"2013"},{"title":"Local Search and the Traveling Salesman Problem: A Feature-Based Characterization of Problem Hardness","date_updated":"2023-12-13T10:48:58Z","publisher":"Springer-Verlag","author":[{"last_name":"Mersmann","full_name":"Mersmann, Olaf","first_name":"Olaf"},{"first_name":"Bernd","last_name":"Bischl","full_name":"Bischl, Bernd"},{"orcid":"0000-0002-4121-4668","last_name":"Bossek","id":"102979","full_name":"Bossek, Jakob","first_name":"Jakob"},{"full_name":"Trautmann, Heike","last_name":"Trautmann","first_name":"Heike"},{"first_name":"Markus","full_name":"Wagner, Markus","last_name":"Wagner"},{"full_name":"Neumann, Frank","last_name":"Neumann","first_name":"Frank"}],"date_created":"2023-11-14T15:58:59Z","year":"2012","place":"Berlin, Heidelberg","page":"115–129","citation":{"ieee":"O. Mersmann, B. Bischl, J. Bossek, H. Trautmann, M. Wagner, and F. Neumann, “Local Search and the Traveling Salesman Problem: A Feature-Based Characterization of Problem Hardness,” in <i>Revised Selected Papers of the 6th International Conference on Learning and Intelligent Optimization - Volume 7219</i>, 2012, pp. 115–129.","chicago":"Mersmann, Olaf, Bernd Bischl, Jakob Bossek, Heike Trautmann, Markus Wagner, and Frank Neumann. “Local Search and the Traveling Salesman Problem: A Feature-Based Characterization of Problem Hardness.” In <i>Revised Selected Papers of the 6th International Conference on Learning and Intelligent Optimization - Volume 7219</i>, 115–129. LION 6. Berlin, Heidelberg: Springer-Verlag, 2012.","ama":"Mersmann O, Bischl B, Bossek J, Trautmann H, Wagner M, Neumann F. Local Search and the Traveling Salesman Problem: A Feature-Based Characterization of Problem Hardness. In: <i>Revised Selected Papers of the 6th International Conference on Learning and Intelligent Optimization - Volume 7219</i>. LION 6. Springer-Verlag; 2012:115–129.","mla":"Mersmann, Olaf, et al. “Local Search and the Traveling Salesman Problem: A Feature-Based Characterization of Problem Hardness.” <i>Revised Selected Papers of the 6th International Conference on Learning and Intelligent Optimization - Volume 7219</i>, Springer-Verlag, 2012, pp. 115–129.","bibtex":"@inproceedings{Mersmann_Bischl_Bossek_Trautmann_Wagner_Neumann_2012, place={Berlin, Heidelberg}, series={LION 6}, title={Local Search and the Traveling Salesman Problem: A Feature-Based Characterization of Problem Hardness}, booktitle={Revised Selected Papers of the 6th International Conference on Learning and Intelligent Optimization - Volume 7219}, publisher={Springer-Verlag}, author={Mersmann, Olaf and Bischl, Bernd and Bossek, Jakob and Trautmann, Heike and Wagner, Markus and Neumann, Frank}, year={2012}, pages={115–129}, collection={LION 6} }","short":"O. Mersmann, B. Bischl, J. Bossek, H. Trautmann, M. Wagner, F. Neumann, in: Revised Selected Papers of the 6th International Conference on Learning and Intelligent Optimization - Volume 7219, Springer-Verlag, Berlin, Heidelberg, 2012, pp. 115–129.","apa":"Mersmann, O., Bischl, B., Bossek, J., Trautmann, H., Wagner, M., &#38; Neumann, F. (2012). Local Search and the Traveling Salesman Problem: A Feature-Based Characterization of Problem Hardness. <i>Revised Selected Papers of the 6th International Conference on Learning and Intelligent Optimization - Volume 7219</i>, 115–129."},"publication_identifier":{"isbn":["978-3-642-34412-1"]},"keyword":["2-opt","Classification","Feature Selection","MARS","TSP"],"language":[{"iso":"eng"}],"extern":"1","_id":"48890","department":[{"_id":"819"}],"user_id":"102979","series_title":"LION 6","abstract":[{"text":"With this paper we contribute to the understanding of the success of 2-opt based local search algorithms for solving the traveling salesman problem TSP. Although 2-opt is widely used in practice, it is hard to understand its success from a theoretical perspective. We take a statistical approach and examine the features of TSP instances that make the problem either hard or easy to solve. As a measure of problem difficulty for 2-opt we use the approximation ratio that it achieves on a given instance. Our investigations point out important features that make TSP instances hard or easy to be approximated by 2-opt.","lang":"eng"}],"status":"public","publication":"Revised Selected Papers of the 6th International Conference on Learning and Intelligent Optimization - Volume 7219","type":"conference"}]