[{"citation":{"ama":"Horák K, Bošanský B, Chatterjee K. Goal-HSVI: Heuristic search value iteration for goal-POMDPs. In: Proceedings of the Twenty-Seventh International Joint Conference on Artificial Intelligence. Vol 2018-July. IJCAI; 2018:4764-4770. doi:10.24963/ijcai.2018/662","apa":"Horák, K., Bošanský, B., & Chatterjee, K. (2018). Goal-HSVI: Heuristic search value iteration for goal-POMDPs. In Proceedings of the Twenty-Seventh International Joint Conference on Artificial Intelligence (Vol. 2018–July, pp. 4764–4770). Stockholm, Sweden: IJCAI. https://doi.org/10.24963/ijcai.2018/662","ieee":"K. Horák, B. Bošanský, and K. Chatterjee, “Goal-HSVI: Heuristic search value iteration for goal-POMDPs,” in Proceedings of the Twenty-Seventh International Joint Conference on Artificial Intelligence, Stockholm, Sweden, 2018, vol. 2018–July, pp. 4764–4770.","short":"K. Horák, B. Bošanský, K. Chatterjee, in:, Proceedings of the Twenty-Seventh International Joint Conference on Artificial Intelligence, IJCAI, 2018, pp. 4764–4770.","mla":"Horák, Karel, et al. “Goal-HSVI: Heuristic Search Value Iteration for Goal-POMDPs.” Proceedings of the Twenty-Seventh International Joint Conference on Artificial Intelligence, vol. 2018–July, IJCAI, 2018, pp. 4764–70, doi:10.24963/ijcai.2018/662.","ista":"Horák K, Bošanský B, Chatterjee K. 2018. Goal-HSVI: Heuristic search value iteration for goal-POMDPs. Proceedings of the Twenty-Seventh International Joint Conference on Artificial Intelligence. IJCAI: International Joint Conference on Artificial Intelligence vol. 2018–July, 4764–4770.","chicago":"Horák, Karel, Branislav Bošanský, and Krishnendu Chatterjee. “Goal-HSVI: Heuristic Search Value Iteration for Goal-POMDPs.” In Proceedings of the Twenty-Seventh International Joint Conference on Artificial Intelligence, 2018–July:4764–70. IJCAI, 2018. https://doi.org/10.24963/ijcai.2018/662."},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","external_id":{"isi":["000764175404127"]},"article_processing_charge":"No","publist_id":"8030","author":[{"full_name":"Horák, Karel","last_name":"Horák","first_name":"Karel"},{"first_name":"Branislav","last_name":"Bošanský","full_name":"Bošanský, Branislav"},{"last_name":"Chatterjee","full_name":"Chatterjee, Krishnendu","orcid":"0000-0002-4561-241X","first_name":"Krishnendu","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87"}],"title":"Goal-HSVI: Heuristic search value iteration for goal-POMDPs","project":[{"grant_number":"ICT15-003","name":"Efficient Algorithms for Computer Aided Verification","_id":"25892FC0-B435-11E9-9278-68D0E5697425"},{"name":"Rigorous Systems Engineering","grant_number":"S 11407_N23","_id":"25832EC2-B435-11E9-9278-68D0E5697425","call_identifier":"FWF"},{"call_identifier":"FP7","_id":"2581B60A-B435-11E9-9278-68D0E5697425","name":"Quantitative Graph Games: Theory and Applications","grant_number":"279307"}],"year":"2018","isi":1,"publication":"Proceedings of the Twenty-Seventh International Joint Conference on Artificial Intelligence","day":"01","page":"4764 - 4770","date_created":"2018-12-11T11:44:13Z","doi":"10.24963/ijcai.2018/662","date_published":"2018-07-01T00:00:00Z","acknowledgement":"∗This work has been supported by Vienna Science and Technology Fund (WWTF) Project ICT15-003, Austrian Science Fund (FWF) NFN Grant No S11407-N23 (RiSE/SHiNE), and ERC Starting grant (279307: Graph Games). This research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Number W911NF-13-2-0045 (ARL Cyber Security CRA). ","oa":1,"publisher":"IJCAI","quality_controlled":"1","date_updated":"2023-09-19T14:44:59Z","department":[{"_id":"KrCh"}],"_id":"25","conference":{"start_date":"2018-07-13","end_date":"2018-07-19","location":"Stockholm, Sweden","name":"IJCAI: International Joint Conference on Artificial Intelligence"},"type":"conference","status":"public","publication_status":"published","language":[{"iso":"eng"}],"ec_funded":1,"volume":"2018-July","abstract":[{"lang":"eng","text":"Partially observable Markov decision processes (POMDPs) are the standard models for planning under uncertainty with both finite and infinite horizon. Besides the well-known discounted-sum objective, indefinite-horizon objective (aka Goal-POMDPs) is another classical objective for POMDPs. In this case, given a set of target states and a positive cost for each transition, the optimization objective is to minimize the expected total cost until a target state is reached. In the literature, RTDP-Bel or heuristic search value iteration (HSVI) have been used for solving Goal-POMDPs. Neither of these algorithms has theoretical convergence guarantees, and HSVI may even fail to terminate its trials. We give the following contributions: (1) We discuss the challenges introduced in Goal-POMDPs and illustrate how they prevent the original HSVI from converging. (2) We present a novel algorithm inspired by HSVI, termed Goal-HSVI, and show that our algorithm has convergence guarantees. (3) We show that Goal-HSVI outperforms RTDP-Bel on a set of well-known examples."}],"oa_version":"Published Version","main_file_link":[{"url":"https://doi.org/10.24963/ijcai.2018/662","open_access":"1"}],"scopus_import":"1","month":"07"},{"day":"01","year":"2018","isi":1,"date_created":"2018-12-11T11:44:13Z","doi":"10.24963/ijcai.2018/652","date_published":"2018-07-01T00:00:00Z","page":"4692 - 4699","acknowledgement":"This research was supported by the Vienna Science and Technology Fund (WWTF) grant ICT15-003; Austrian Science Fund (FWF): S11407-N23(RiSE/SHiNE);and an ERC Start Grant (279307:Graph Games).\r\n","oa":1,"quality_controlled":"1","publisher":"IJCAI","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"mla":"Chatterjee, Krishnendu, et al. Expectation Optimization with Probabilistic Guarantees in POMDPs with Discounted-Sum Objectives. Vol. 2018, IJCAI, 2018, pp. 4692–99, doi:10.24963/ijcai.2018/652.","ieee":"K. Chatterjee, A. Elgyütt, P. Novotný, and O. Rouillé, “Expectation optimization with probabilistic guarantees in POMDPs with discounted-sum objectives,” presented at the IJCAI: International Joint Conference on Artificial Intelligence, Stockholm, Sweden, 2018, vol. 2018, pp. 4692–4699.","short":"K. Chatterjee, A. Elgyütt, P. Novotný, O. Rouillé, in:, IJCAI, 2018, pp. 4692–4699.","apa":"Chatterjee, K., Elgyütt, A., Novotný, P., & Rouillé, O. (2018). Expectation optimization with probabilistic guarantees in POMDPs with discounted-sum objectives (Vol. 2018, pp. 4692–4699). Presented at the IJCAI: International Joint Conference on Artificial Intelligence, Stockholm, Sweden: IJCAI. https://doi.org/10.24963/ijcai.2018/652","ama":"Chatterjee K, Elgyütt A, Novotný P, Rouillé O. Expectation optimization with probabilistic guarantees in POMDPs with discounted-sum objectives. In: Vol 2018. IJCAI; 2018:4692-4699. doi:10.24963/ijcai.2018/652","chicago":"Chatterjee, Krishnendu, Adrian Elgyütt, Petr Novotný, and Owen Rouillé. “Expectation Optimization with Probabilistic Guarantees in POMDPs with Discounted-Sum Objectives,” 2018:4692–99. IJCAI, 2018. https://doi.org/10.24963/ijcai.2018/652.","ista":"Chatterjee K, Elgyütt A, Novotný P, Rouillé O. 2018. Expectation optimization with probabilistic guarantees in POMDPs with discounted-sum objectives. IJCAI: International Joint Conference on Artificial Intelligence vol. 2018, 4692–4699."},"title":"Expectation optimization with probabilistic guarantees in POMDPs with discounted-sum objectives","external_id":{"isi":["000764175404117"],"arxiv":["1804.10601"]},"article_processing_charge":"No","author":[{"full_name":"Chatterjee, Krishnendu","orcid":"0000-0002-4561-241X","last_name":"Chatterjee","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87","first_name":"Krishnendu"},{"id":"4A2E9DBA-F248-11E8-B48F-1D18A9856A87","first_name":"Adrian","full_name":"Elgyütt, Adrian","last_name":"Elgyütt"},{"full_name":"Novotny, Petr","last_name":"Novotny","id":"3CC3B868-F248-11E8-B48F-1D18A9856A87","first_name":"Petr"},{"first_name":"Owen","full_name":"Rouillé, Owen","last_name":"Rouillé"}],"publist_id":"8031","project":[{"name":"Efficient Algorithms for Computer Aided Verification","grant_number":"ICT15-003","_id":"25892FC0-B435-11E9-9278-68D0E5697425"},{"name":"Rigorous Systems Engineering","grant_number":"S 11407_N23","_id":"25832EC2-B435-11E9-9278-68D0E5697425","call_identifier":"FWF"},{"call_identifier":"FP7","_id":"2581B60A-B435-11E9-9278-68D0E5697425","name":"Quantitative Graph Games: Theory and Applications","grant_number":"279307"}],"language":[{"iso":"eng"}],"publication_status":"published","ec_funded":1,"volume":2018,"oa_version":"Preprint","abstract":[{"lang":"eng","text":"Partially-observable Markov decision processes (POMDPs) with discounted-sum payoff are a standard framework to model a wide range of problems related to decision making under uncertainty. Traditionally, the goal has been to obtain policies that optimize the expectation of the discounted-sum payoff. A key drawback of the expectation measure is that even low probability events with extreme payoff can significantly affect the expectation, and thus the obtained policies are not necessarily risk-averse. An alternate approach is to optimize the probability that the payoff is above a certain threshold, which allows obtaining risk-averse policies, but ignores optimization of the expectation. We consider the expectation optimization with probabilistic guarantee (EOPG) problem, where the goal is to optimize the expectation ensuring that the payoff is above a given threshold with at least a specified probability. We present several results on the EOPG problem, including the first algorithm to solve it."}],"intvolume":" 2018","month":"07","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1804.10601"}],"scopus_import":"1","date_updated":"2023-09-19T14:45:48Z","department":[{"_id":"KrCh"},{"_id":"ToHe"}],"_id":"24","status":"public","conference":{"start_date":"2018-07-13","location":"Stockholm, Sweden","end_date":"2018-07-19","name":"IJCAI: International Joint Conference on Artificial Intelligence"},"type":"conference"},{"project":[{"name":"Modern Graph Algorithmic Techniques in Formal Verification","grant_number":"P 23499-N23","_id":"2584A770-B435-11E9-9278-68D0E5697425","call_identifier":"FWF"},{"name":"Quantitative Graph Games: Theory and Applications","grant_number":"279307","call_identifier":"FP7","_id":"2581B60A-B435-11E9-9278-68D0E5697425"},{"call_identifier":"FWF","_id":"25832EC2-B435-11E9-9278-68D0E5697425","name":"Rigorous Systems Engineering","grant_number":"S 11407_N23"},{"_id":"2587B514-B435-11E9-9278-68D0E5697425","name":"Microsoft Research Faculty Fellowship"}],"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"ista":"Chatterjee K, Chemlík M, Topcu U. 2018. Sensor synthesis for POMDPs with reachability objectives. ICAPS: International Conference on Automated Planning and Scheduling, ICAPS, vol. 2018, 47–55.","chicago":"Chatterjee, Krishnendu, Martin Chemlík, and Ufuk Topcu. “Sensor Synthesis for POMDPs with Reachability Objectives,” 2018:47–55. AAAI Press, 2018.","ieee":"K. Chatterjee, M. Chemlík, and U. Topcu, “Sensor synthesis for POMDPs with reachability objectives,” presented at the ICAPS: International Conference on Automated Planning and Scheduling, Delft, Netherlands, 2018, vol. 2018, pp. 47–55.","short":"K. Chatterjee, M. Chemlík, U. Topcu, in:, AAAI Press, 2018, pp. 47–55.","apa":"Chatterjee, K., Chemlík, M., & Topcu, U. (2018). Sensor synthesis for POMDPs with reachability objectives (Vol. 2018, pp. 47–55). Presented at the ICAPS: International Conference on Automated Planning and Scheduling, Delft, Netherlands: AAAI Press.","ama":"Chatterjee K, Chemlík M, Topcu U. Sensor synthesis for POMDPs with reachability objectives. In: Vol 2018. AAAI Press; 2018:47-55.","mla":"Chatterjee, Krishnendu, et al. Sensor Synthesis for POMDPs with Reachability Objectives. Vol. 2018, AAAI Press, 2018, pp. 47–55."},"title":"Sensor synthesis for POMDPs with reachability objectives","author":[{"id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87","first_name":"Krishnendu","full_name":"Chatterjee, Krishnendu","orcid":"0000-0002-4561-241X","last_name":"Chatterjee"},{"last_name":"Chemlík","full_name":"Chemlík, Martin","first_name":"Martin"},{"first_name":"Ufuk","last_name":"Topcu","full_name":"Topcu, Ufuk"}],"publist_id":"8021","article_processing_charge":"No","external_id":{"arxiv":["1710.00675"],"isi":["000492986200006"]},"quality_controlled":"1","publisher":"AAAI Press","oa":1,"day":"01","isi":1,"year":"2018","date_published":"2018-06-01T00:00:00Z","date_created":"2018-12-11T11:44:16Z","page":"47 - 55","_id":"34","status":"public","type":"conference","conference":{"location":"Delft, Netherlands","end_date":"2018-06-29","start_date":"2018-06-24","name":"ICAPS: International Conference on Automated Planning and Scheduling"},"date_updated":"2023-09-19T14:44:14Z","department":[{"_id":"KrCh"}],"oa_version":"Preprint","abstract":[{"lang":"eng","text":"Partially observable Markov decision processes (POMDPs) are widely used in probabilistic planning problems in which an agent interacts with an environment using noisy and imprecise sensors. We study a setting in which the sensors are only partially defined and the goal is to synthesize “weakest” additional sensors, such that in the resulting POMDP, there is a small-memory policy for the agent that almost-surely (with probability 1) satisfies a reachability objective. We show that the problem is NP-complete, and present a symbolic algorithm by encoding the problem into SAT instances. We illustrate trade-offs between the amount of memory of the policy and the number of additional sensors on a simple example. We have implemented our approach and consider three classical POMDP examples from the literature, and show that in all the examples the number of sensors can be significantly decreased (as compared to the existing solutions in the literature) without increasing the complexity of the policies."}],"month":"06","intvolume":" 2018","alternative_title":["ICAPS"],"scopus_import":"1","main_file_link":[{"url":"https://arxiv.org/abs/1710.00675","open_access":"1"}],"language":[{"iso":"eng"}],"publication_status":"published","volume":2018,"ec_funded":1},{"title":"Superconcentrators of density 25.3","article_processing_charge":"No","external_id":{"arxiv":["1405.7828"],"isi":["000446809500022"]},"publist_id":"8037","author":[{"first_name":"Vladimir","id":"3D50B0BA-F248-11E8-B48F-1D18A9856A87","full_name":"Kolmogorov, Vladimir","last_name":"Kolmogorov"},{"full_name":"Rolinek, Michal","last_name":"Rolinek","id":"3CB3BC06-F248-11E8-B48F-1D18A9856A87","first_name":"Michal"}],"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"chicago":"Kolmogorov, Vladimir, and Michal Rolinek. “Superconcentrators of Density 25.3.” Ars Combinatoria. Charles Babbage Research Centre, 2018.","ista":"Kolmogorov V, Rolinek M. 2018. Superconcentrators of density 25.3. Ars Combinatoria. 141(10), 269–304.","mla":"Kolmogorov, Vladimir, and Michal Rolinek. “Superconcentrators of Density 25.3.” Ars Combinatoria, vol. 141, no. 10, Charles Babbage Research Centre, 2018, pp. 269–304.","short":"V. Kolmogorov, M. Rolinek, Ars Combinatoria 141 (2018) 269–304.","ieee":"V. Kolmogorov and M. Rolinek, “Superconcentrators of density 25.3,” Ars Combinatoria, vol. 141, no. 10. Charles Babbage Research Centre, pp. 269–304, 2018.","apa":"Kolmogorov, V., & Rolinek, M. (2018). Superconcentrators of density 25.3. Ars Combinatoria. Charles Babbage Research Centre.","ama":"Kolmogorov V, Rolinek M. Superconcentrators of density 25.3. Ars Combinatoria. 2018;141(10):269-304."},"date_created":"2018-12-11T11:44:11Z","date_published":"2018-10-01T00:00:00Z","page":"269 - 304","publication":"Ars Combinatoria","day":"01","year":"2018","isi":1,"oa":1,"quality_controlled":"1","publisher":"Charles Babbage Research Centre","department":[{"_id":"VlKo"}],"date_updated":"2023-09-19T14:46:18Z","status":"public","type":"journal_article","_id":"18","volume":141,"issue":"10","language":[{"iso":"eng"}],"publication_status":"published","publication_identifier":{"issn":["0381-7032"]},"intvolume":" 141","month":"10","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1405.7828"}],"scopus_import":"1","oa_version":"Preprint","abstract":[{"lang":"eng","text":"An N-superconcentrator is a directed, acyclic graph with N input nodes and N output nodes such that every subset of the inputs and every subset of the outputs of same cardinality can be connected by node-disjoint paths. It is known that linear-size and bounded-degree superconcentrators exist. We prove the existence of such superconcentrators with asymptotic density 25.3 (where the density is the number of edges divided by N). The previously best known densities were 28 [12] and 27.4136 [17]."}]},{"oa":1,"quality_controlled":"1","publisher":"Cambridge University Press","date_created":"2019-04-30T06:09:57Z","date_published":"2018-05-31T00:00:00Z","doi":"10.1017/fms.2018.7","publication":"Forum of Mathematics, Sigma","day":"31","year":"2018","has_accepted_license":"1","isi":1,"project":[{"_id":"256E75B8-B435-11E9-9278-68D0E5697425","call_identifier":"H2020","grant_number":"716117","name":"Optimal Transport and Stochastic Dynamics"}],"article_number":"e7","title":"Any cyclic quadrilateral can be inscribed in any closed convex smooth curve","article_processing_charge":"No","external_id":{"isi":["000433915500001"],"arxiv":["1712.10205"]},"author":[{"first_name":"Arseniy","id":"430D2C90-F248-11E8-B48F-1D18A9856A87","last_name":"Akopyan","orcid":"0000-0002-2548-617X","full_name":"Akopyan, Arseniy"},{"last_name":"Avvakumov","full_name":"Avvakumov, Sergey","id":"3827DAC8-F248-11E8-B48F-1D18A9856A87","first_name":"Sergey"}],"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"chicago":"Akopyan, Arseniy, and Sergey Avvakumov. “Any Cyclic Quadrilateral Can Be Inscribed in Any Closed Convex Smooth Curve.” Forum of Mathematics, Sigma. Cambridge University Press, 2018. https://doi.org/10.1017/fms.2018.7.","ista":"Akopyan A, Avvakumov S. 2018. Any cyclic quadrilateral can be inscribed in any closed convex smooth curve. Forum of Mathematics, Sigma. 6, e7.","mla":"Akopyan, Arseniy, and Sergey Avvakumov. “Any Cyclic Quadrilateral Can Be Inscribed in Any Closed Convex Smooth Curve.” Forum of Mathematics, Sigma, vol. 6, e7, Cambridge University Press, 2018, doi:10.1017/fms.2018.7.","ama":"Akopyan A, Avvakumov S. Any cyclic quadrilateral can be inscribed in any closed convex smooth curve. Forum of Mathematics, Sigma. 2018;6. doi:10.1017/fms.2018.7","apa":"Akopyan, A., & Avvakumov, S. (2018). Any cyclic quadrilateral can be inscribed in any closed convex smooth curve. Forum of Mathematics, Sigma. Cambridge University Press. https://doi.org/10.1017/fms.2018.7","short":"A. Akopyan, S. Avvakumov, Forum of Mathematics, Sigma 6 (2018).","ieee":"A. Akopyan and S. Avvakumov, “Any cyclic quadrilateral can be inscribed in any closed convex smooth curve,” Forum of Mathematics, Sigma, vol. 6. Cambridge University Press, 2018."},"intvolume":" 6","month":"05","oa_version":"Published Version","abstract":[{"lang":"eng","text":"We prove that any cyclic quadrilateral can be inscribed in any closed convex C1-curve. The smoothness condition is not required if the quadrilateral is a rectangle."}],"ec_funded":1,"volume":6,"related_material":{"record":[{"relation":"dissertation_contains","id":"8156","status":"public"}]},"language":[{"iso":"eng"}],"file":[{"file_size":249246,"date_updated":"2020-07-14T12:47:28Z","creator":"dernst","file_name":"2018_ForumMahtematics_Akopyan.pdf","date_created":"2019-04-30T06:14:58Z","content_type":"application/pdf","relation":"main_file","access_level":"open_access","checksum":"5a71b24ba712a3eb2e46165a38fbc30a","file_id":"6356"}],"publication_status":"published","publication_identifier":{"issn":["2050-5094"]},"status":"public","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"type":"journal_article","_id":"6355","department":[{"_id":"UlWa"},{"_id":"HeEd"},{"_id":"JaMa"}],"file_date_updated":"2020-07-14T12:47:28Z","ddc":["510"],"date_updated":"2023-09-19T14:50:12Z"},{"citation":{"chicago":"Pozzi, Maria, Eder Miguel Villalba, Raphael Deimel, Monica Malvezzi, Bernd Bickel, Oliver Brock, and Domenico Prattichizzo. “Efficient FEM-Based Simulation of Soft Robots Modeled as Kinematic Chains.” IEEE, 2018. https://doi.org/10.1109/icra.2018.8461106.","ista":"Pozzi M, Miguel Villalba E, Deimel R, Malvezzi M, Bickel B, Brock O, Prattichizzo D. 2018. Efficient FEM-based simulation of soft robots modeled as kinematic chains. ICRA: International Conference on Robotics and Automation, 8461106.","mla":"Pozzi, Maria, et al. Efficient FEM-Based Simulation of Soft Robots Modeled as Kinematic Chains. 8461106, IEEE, 2018, doi:10.1109/icra.2018.8461106.","ieee":"M. Pozzi et al., “Efficient FEM-based simulation of soft robots modeled as kinematic chains,” presented at the ICRA: International Conference on Robotics and Automation, Brisbane, Australia, 2018.","short":"M. Pozzi, E. Miguel Villalba, R. Deimel, M. Malvezzi, B. Bickel, O. Brock, D. Prattichizzo, in:, IEEE, 2018.","ama":"Pozzi M, Miguel Villalba E, Deimel R, et al. Efficient FEM-based simulation of soft robots modeled as kinematic chains. In: IEEE; 2018. doi:10.1109/icra.2018.8461106","apa":"Pozzi, M., Miguel Villalba, E., Deimel, R., Malvezzi, M., Bickel, B., Brock, O., & Prattichizzo, D. (2018). Efficient FEM-based simulation of soft robots modeled as kinematic chains. Presented at the ICRA: International Conference on Robotics and Automation, Brisbane, Australia: IEEE. https://doi.org/10.1109/icra.2018.8461106"},"date_updated":"2023-09-19T14:49:03Z","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","article_processing_charge":"No","external_id":{"isi":["000446394503031"]},"author":[{"full_name":"Pozzi, Maria","last_name":"Pozzi","first_name":"Maria"},{"id":"3FB91342-F248-11E8-B48F-1D18A9856A87","first_name":"Eder","last_name":"Miguel Villalba","orcid":"0000-0001-5665-0430","full_name":"Miguel Villalba, Eder"},{"first_name":"Raphael","full_name":"Deimel, Raphael","last_name":"Deimel"},{"first_name":"Monica","full_name":"Malvezzi, Monica","last_name":"Malvezzi"},{"orcid":"0000-0001-6511-9385","full_name":"Bickel, Bernd","last_name":"Bickel","first_name":"Bernd","id":"49876194-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Brock","full_name":"Brock, Oliver","first_name":"Oliver"},{"first_name":"Domenico","full_name":"Prattichizzo, Domenico","last_name":"Prattichizzo"}],"title":"Efficient FEM-based simulation of soft robots modeled as kinematic chains","department":[{"_id":"BeBi"}],"_id":"6195","article_number":"8461106","conference":{"name":"ICRA: International Conference on Robotics and Automation","start_date":"2018-05-21","end_date":"2018-05-25","location":"Brisbane, Australia"},"type":"conference","status":"public","publication_status":"published","year":"2018","publication_identifier":{"isbn":["9781538630815"]},"isi":1,"language":[{"iso":"eng"}],"day":"10","date_created":"2019-04-04T09:50:38Z","date_published":"2018-09-10T00:00:00Z","doi":"10.1109/icra.2018.8461106","abstract":[{"lang":"eng","text":"In the context of robotic manipulation and grasping, the shift from a view that is static (force closure of a single posture) and contact-deprived (only contact for force closure is allowed, everything else is obstacle) towards a view that is dynamic and contact-rich (soft manipulation) has led to an increased interest in soft hands. These hands can easily exploit environmental constraints and object surfaces without risk, and safely interact with humans, but present also some challenges. Designing them is difficult, as well as predicting, modelling, and “programming” their interactions with the objects and the environment. This paper tackles the problem of simulating them in a fast and effective way, leveraging on novel and existing simulation technologies. We present a triple-layered simulation framework where dynamic properties such as stiffness are determined from slow but accurate FEM simulation data once, and then condensed into a lumped parameter model that can be used to fast simulate soft fingers and soft hands. We apply our approach to the simulation of soft pneumatic fingers."}],"oa_version":"None","scopus_import":"1","publisher":"IEEE","quality_controlled":"1","month":"09"},{"external_id":{"isi":["000540656400026"]},"article_processing_charge":"No","author":[{"full_name":"Park, Sunoo","last_name":"Park","first_name":"Sunoo"},{"first_name":"Albert","full_name":"Kwon, Albert","last_name":"Kwon"},{"last_name":"Fuchsbauer","full_name":"Fuchsbauer, Georg","first_name":"Georg","id":"46B4C3EE-F248-11E8-B48F-1D18A9856A87"},{"id":"3E0BFE38-F248-11E8-B48F-1D18A9856A87","first_name":"Peter","full_name":"Gazi, Peter","last_name":"Gazi"},{"first_name":"Joel F","id":"2A8DFA8C-F248-11E8-B48F-1D18A9856A87","last_name":"Alwen","full_name":"Alwen, Joel F"},{"first_name":"Krzysztof Z","id":"3E04A7AA-F248-11E8-B48F-1D18A9856A87","full_name":"Pietrzak, Krzysztof Z","orcid":"0000-0002-9139-1654","last_name":"Pietrzak"}],"title":"SpaceMint: A cryptocurrency based on proofs of space","citation":{"ista":"Park S, Kwon A, Fuchsbauer G, Gazi P, Alwen JF, Pietrzak KZ. 2018. SpaceMint: A cryptocurrency based on proofs of space. 22nd International Conference on Financial Cryptography and Data Security. FC: Financial Cryptography and Data Security, LNCS, vol. 10957, 480–499.","chicago":"Park, Sunoo, Albert Kwon, Georg Fuchsbauer, Peter Gazi, Joel F Alwen, and Krzysztof Z Pietrzak. “SpaceMint: A Cryptocurrency Based on Proofs of Space.” In 22nd International Conference on Financial Cryptography and Data Security, 10957:480–99. Springer Nature, 2018. https://doi.org/10.1007/978-3-662-58387-6_26.","short":"S. Park, A. Kwon, G. Fuchsbauer, P. Gazi, J.F. Alwen, K.Z. Pietrzak, in:, 22nd International Conference on Financial Cryptography and Data Security, Springer Nature, 2018, pp. 480–499.","ieee":"S. Park, A. Kwon, G. Fuchsbauer, P. Gazi, J. F. Alwen, and K. Z. Pietrzak, “SpaceMint: A cryptocurrency based on proofs of space,” in 22nd International Conference on Financial Cryptography and Data Security, Nieuwpoort, Curacao, 2018, vol. 10957, pp. 480–499.","ama":"Park S, Kwon A, Fuchsbauer G, Gazi P, Alwen JF, Pietrzak KZ. SpaceMint: A cryptocurrency based on proofs of space. In: 22nd International Conference on Financial Cryptography and Data Security. Vol 10957. Springer Nature; 2018:480-499. doi:10.1007/978-3-662-58387-6_26","apa":"Park, S., Kwon, A., Fuchsbauer, G., Gazi, P., Alwen, J. F., & Pietrzak, K. Z. (2018). SpaceMint: A cryptocurrency based on proofs of space. In 22nd International Conference on Financial Cryptography and Data Security (Vol. 10957, pp. 480–499). Nieuwpoort, Curacao: Springer Nature. https://doi.org/10.1007/978-3-662-58387-6_26","mla":"Park, Sunoo, et al. “SpaceMint: A Cryptocurrency Based on Proofs of Space.” 22nd International Conference on Financial Cryptography and Data Security, vol. 10957, Springer Nature, 2018, pp. 480–99, doi:10.1007/978-3-662-58387-6_26."},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","project":[{"name":"Teaching Old Crypto New Tricks","grant_number":"682815","call_identifier":"H2020","_id":"258AA5B2-B435-11E9-9278-68D0E5697425"}],"page":"480-499","date_created":"2019-10-14T06:35:38Z","doi":"10.1007/978-3-662-58387-6_26","date_published":"2018-12-07T00:00:00Z","year":"2018","isi":1,"publication":"22nd International Conference on Financial Cryptography and Data Security","day":"07","oa":1,"publisher":"Springer Nature","quality_controlled":"1","department":[{"_id":"KrPi"}],"date_updated":"2023-09-19T15:02:13Z","conference":{"start_date":"2018-02-26","end_date":"2018-03-02","location":"Nieuwpoort, Curacao","name":"FC: Financial Cryptography and Data Security"},"type":"conference","status":"public","_id":"6941","ec_funded":1,"volume":10957,"publication_status":"published","publication_identifier":{"eissn":["1611-3349"],"isbn":["9783662583869","9783662583876"],"issn":["0302-9743"]},"language":[{"iso":"eng"}],"main_file_link":[{"open_access":"1","url":"https://eprint.iacr.org/2015/528"}],"scopus_import":"1","alternative_title":["LNCS"],"intvolume":" 10957","month":"12","abstract":[{"text":"Bitcoin has become the most successful cryptocurrency ever deployed, and its most distinctive feature is that it is decentralized. Its underlying protocol (Nakamoto consensus) achieves this by using proof of work, which has the drawback that it causes the consumption of vast amounts of energy to maintain the ledger. Moreover, Bitcoin mining dynamics have become less distributed over time.\r\n\r\nTowards addressing these issues, we propose SpaceMint, a cryptocurrency based on proofs of space instead of proofs of work. Miners in SpaceMint dedicate disk space rather than computation. We argue that SpaceMint’s design solves or alleviates several of Bitcoin’s issues: most notably, its large energy consumption. SpaceMint also rewards smaller miners fairly according to their contribution to the network, thus incentivizing more distributed participation.\r\n\r\nThis paper adapts proof of space to enable its use in cryptocurrency, studies the attacks that can arise against a Bitcoin-like blockchain that uses proof of space, and proposes a new blockchain format and transaction types to address these attacks. Our prototype shows that initializing 1 TB for mining takes about a day (a one-off setup cost), and miners spend on average just a fraction of a second per block mined. Finally, we provide a game-theoretic analysis modeling SpaceMint as an extensive game (the canonical game-theoretic notion for games that take place over time) and show that this stylized game satisfies a strong equilibrium notion, thereby arguing for SpaceMint ’s stability and consensus.","lang":"eng"}],"oa_version":"Submitted Version"},{"language":[{"iso":"eng"}],"file":[{"date_created":"2019-05-28T12:40:05Z","file_name":"2018_rupress_Moalli.pdf","date_updated":"2020-07-14T12:47:32Z","file_size":3841660,"creator":"kschuh","checksum":"86ae5331f9bfced9a6358a790a04bef4","file_id":"6498","content_type":"application/pdf","access_level":"open_access","relation":"main_file"}],"publication_status":"published","publication_identifier":{"issn":["0022-1007"],"eissn":["1540-9538"]},"license":"https://creativecommons.org/licenses/by-nc-sa/4.0/","issue":"7","volume":2015,"oa_version":"Published Version","abstract":[{"lang":"eng","text":"T cells are actively scanning pMHC-presenting cells in lymphoid organs and nonlymphoid tissues (NLTs) with divergent topologies and confinement. How the T cell actomyosin cytoskeleton facilitates this task in distinct environments is incompletely understood. Here, we show that lack of Myosin IXb (Myo9b), a negative regulator of the small GTPase Rho, led to increased Rho-GTP levels and cell surface stiffness in primary T cells. Nonetheless, intravital imaging revealed robust motility of Myo9b−/− CD8+ T cells in lymphoid tissue and similar expansion and differentiation during immune responses. In contrast, accumulation of Myo9b−/− CD8+ T cells in NLTs was strongly impaired. Specifically, Myo9b was required for T cell crossing of basement membranes, such as those which are present between dermis and epidermis. As consequence, Myo9b−/− CD8+ T cells showed impaired control of skin infections. In sum, we show that Myo9b is critical for the CD8+ T cell adaptation from lymphoid to NLT surveillance and the establishment of protective tissue–resident T cell populations."}],"intvolume":" 2015","month":"06","scopus_import":"1","ddc":["570"],"date_updated":"2023-09-19T14:52:08Z","file_date_updated":"2020-07-14T12:47:32Z","department":[{"_id":"MiSi"}],"_id":"6497","status":"public","tmp":{"name":"Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)","image":"/images/cc_by_nc_sa.png","legal_code_url":"https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode","short":"CC BY-NC-SA (4.0)"},"type":"journal_article","publication":"The Journal of Experimental Medicine","day":"06","year":"2018","has_accepted_license":"1","isi":1,"date_created":"2019-05-28T12:36:47Z","doi":"10.1084/jem.20170896","date_published":"2018-06-06T00:00:00Z","page":"1869–1890","oa":1,"publisher":"Rockefeller University Press","quality_controlled":"1","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"ieee":"F. Moalli et al., “The Rho regulator Myosin IXb enables nonlymphoid tissue seeding of protective CD8+T cells,” The Journal of Experimental Medicine, vol. 2015, no. 7. Rockefeller University Press, pp. 1869–1890, 2018.","short":"F. Moalli, X. Ficht, P. Germann, M. Vladymyrov, B. Stolp, I. de Vries, R. Lyck, J. Balmer, A. Fiocchi, M. Kreutzfeldt, D. Merkler, M. Iannacone, A. Ariga, M.H. Stoffel, J. Sharpe, M. Bähler, M.K. Sixt, A. Diz-Muñoz, J.V. Stein, The Journal of Experimental Medicine 2015 (2018) 1869–1890.","ama":"Moalli F, Ficht X, Germann P, et al. The Rho regulator Myosin IXb enables nonlymphoid tissue seeding of protective CD8+T cells. The Journal of Experimental Medicine. 2018;2015(7):1869–1890. doi:10.1084/jem.20170896","apa":"Moalli, F., Ficht, X., Germann, P., Vladymyrov, M., Stolp, B., de Vries, I., … Stein, J. V. (2018). The Rho regulator Myosin IXb enables nonlymphoid tissue seeding of protective CD8+T cells. The Journal of Experimental Medicine. Rockefeller University Press. https://doi.org/10.1084/jem.20170896","mla":"Moalli, Federica, et al. “The Rho Regulator Myosin IXb Enables Nonlymphoid Tissue Seeding of Protective CD8+T Cells.” The Journal of Experimental Medicine, vol. 2015, no. 7, Rockefeller University Press, 2018, pp. 1869–1890, doi:10.1084/jem.20170896.","ista":"Moalli F, Ficht X, Germann P, Vladymyrov M, Stolp B, de Vries I, Lyck R, Balmer J, Fiocchi A, Kreutzfeldt M, Merkler D, Iannacone M, Ariga A, Stoffel MH, Sharpe J, Bähler M, Sixt MK, Diz-Muñoz A, Stein JV. 2018. The Rho regulator Myosin IXb enables nonlymphoid tissue seeding of protective CD8+T cells. The Journal of Experimental Medicine. 2015(7), 1869–1890.","chicago":"Moalli, Federica, Xenia Ficht, Philipp Germann, Mykhailo Vladymyrov, Bettina Stolp, Ingrid de Vries, Ruth Lyck, et al. “The Rho Regulator Myosin IXb Enables Nonlymphoid Tissue Seeding of Protective CD8+T Cells.” The Journal of Experimental Medicine. Rockefeller University Press, 2018. https://doi.org/10.1084/jem.20170896."},"title":"The Rho regulator Myosin IXb enables nonlymphoid tissue seeding of protective CD8+T cells","external_id":{"isi":["000440822900011"]},"article_processing_charge":"No","author":[{"first_name":"Federica","full_name":"Moalli, Federica","last_name":"Moalli"},{"last_name":"Ficht","full_name":"Ficht, Xenia","first_name":"Xenia"},{"first_name":"Philipp","last_name":"Germann","full_name":"Germann, Philipp"},{"first_name":"Mykhailo","full_name":"Vladymyrov, Mykhailo","last_name":"Vladymyrov"},{"first_name":"Bettina","last_name":"Stolp","full_name":"Stolp, Bettina"},{"full_name":"de Vries, Ingrid","last_name":"de Vries","id":"4C7D837E-F248-11E8-B48F-1D18A9856A87","first_name":"Ingrid"},{"full_name":"Lyck, Ruth","last_name":"Lyck","first_name":"Ruth"},{"full_name":"Balmer, Jasmin","last_name":"Balmer","first_name":"Jasmin"},{"first_name":"Amleto","full_name":"Fiocchi, Amleto","last_name":"Fiocchi"},{"last_name":"Kreutzfeldt","full_name":"Kreutzfeldt, Mario","first_name":"Mario"},{"first_name":"Doron","full_name":"Merkler, Doron","last_name":"Merkler"},{"last_name":"Iannacone","full_name":"Iannacone, Matteo","first_name":"Matteo"},{"full_name":"Ariga, Akitaka","last_name":"Ariga","first_name":"Akitaka"},{"full_name":"Stoffel, Michael H.","last_name":"Stoffel","first_name":"Michael H."},{"first_name":"James","full_name":"Sharpe, James","last_name":"Sharpe"},{"last_name":"Bähler","full_name":"Bähler, Martin","first_name":"Martin"},{"first_name":"Michael K","id":"41E9FBEA-F248-11E8-B48F-1D18A9856A87","last_name":"Sixt","full_name":"Sixt, Michael K","orcid":"0000-0002-6620-9179"},{"last_name":"Diz-Muñoz","full_name":"Diz-Muñoz, Alba","first_name":"Alba"},{"first_name":"Jens V.","last_name":"Stein","full_name":"Stein, Jens V."}]},{"type":"journal_article","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"status":"public","_id":"6499","department":[{"_id":"JoDa"}],"file_date_updated":"2020-07-14T12:47:32Z","date_updated":"2023-09-19T14:52:32Z","ddc":["580"],"scopus_import":"1","month":"09","intvolume":" 19","abstract":[{"lang":"eng","text":"Expansion microscopy is a recently introduced imaging technique that achieves super‐resolution through physically expanding the specimen by ~4×, after embedding into a swellable gel. The resolution attained is, correspondingly, approximately fourfold better than the diffraction limit, or ~70 nm. This is a major improvement over conventional microscopy, but still lags behind modern STED or STORM setups, whose resolution can reach 20–30 nm. We addressed this issue here by introducing an improved gel recipe that enables an expansion factor of ~10× in each dimension, which corresponds to an expansion of the sample volume by more than 1,000‐fold. Our protocol, which we termed X10 microscopy, achieves a resolution of 25–30 nm on conventional epifluorescence microscopes. X10 provides multi‐color images similar or even superior to those produced with more challenging methods, such as STED, STORM, and iterative expansion microscopy (iExM). X10 is therefore the cheapest and easiest option for high‐quality super‐resolution imaging currently available. X10 should be usable in any laboratory, irrespective of the machinery owned or of the technical knowledge."}],"oa_version":"Published Version","volume":19,"issue":"9","publication_identifier":{"eissn":["1469-3178"],"issn":["1469-221X"]},"publication_status":"published","file":[{"date_created":"2019-05-28T13:17:19Z","file_name":"2018_embo_Truckenbrodt.pdf","creator":"kschuh","date_updated":"2020-07-14T12:47:32Z","file_size":2005572,"checksum":"6ec90abc637f09cca3a7b6424d7e7a26","file_id":"6500","access_level":"open_access","relation":"main_file","content_type":"application/pdf"}],"language":[{"iso":"eng"}],"article_number":"e45836","author":[{"id":"45812BD4-F248-11E8-B48F-1D18A9856A87","first_name":"Sven M","last_name":"Truckenbrodt","full_name":"Truckenbrodt, Sven M"},{"first_name":"Manuel","last_name":"Maidorn","full_name":"Maidorn, Manuel"},{"first_name":"Dagmar","last_name":"Crzan","full_name":"Crzan, Dagmar"},{"first_name":"Hanna","last_name":"Wildhagen","full_name":"Wildhagen, Hanna"},{"first_name":"Selda","last_name":"Kabatas","full_name":"Kabatas, Selda"},{"full_name":"Rizzoli, Silvio O","last_name":"Rizzoli","first_name":"Silvio O"}],"external_id":{"isi":["000443682200009"]},"article_processing_charge":"No","title":"X10 expansion microscopy enables 25‐nm resolution on conventional microscopes","citation":{"chicago":"Truckenbrodt, Sven M, Manuel Maidorn, Dagmar Crzan, Hanna Wildhagen, Selda Kabatas, and Silvio O Rizzoli. “X10 Expansion Microscopy Enables 25‐nm Resolution on Conventional Microscopes.” EMBO Reports. EMBO, 2018. https://doi.org/10.15252/embr.201845836.","ista":"Truckenbrodt SM, Maidorn M, Crzan D, Wildhagen H, Kabatas S, Rizzoli SO. 2018. X10 expansion microscopy enables 25‐nm resolution on conventional microscopes. EMBO reports. 19(9), e45836.","mla":"Truckenbrodt, Sven M., et al. “X10 Expansion Microscopy Enables 25‐nm Resolution on Conventional Microscopes.” EMBO Reports, vol. 19, no. 9, e45836, EMBO, 2018, doi:10.15252/embr.201845836.","ama":"Truckenbrodt SM, Maidorn M, Crzan D, Wildhagen H, Kabatas S, Rizzoli SO. X10 expansion microscopy enables 25‐nm resolution on conventional microscopes. EMBO reports. 2018;19(9). doi:10.15252/embr.201845836","apa":"Truckenbrodt, S. M., Maidorn, M., Crzan, D., Wildhagen, H., Kabatas, S., & Rizzoli, S. O. (2018). X10 expansion microscopy enables 25‐nm resolution on conventional microscopes. EMBO Reports. EMBO. https://doi.org/10.15252/embr.201845836","short":"S.M. Truckenbrodt, M. Maidorn, D. Crzan, H. Wildhagen, S. Kabatas, S.O. Rizzoli, EMBO Reports 19 (2018).","ieee":"S. M. Truckenbrodt, M. Maidorn, D. Crzan, H. Wildhagen, S. Kabatas, and S. O. Rizzoli, “X10 expansion microscopy enables 25‐nm resolution on conventional microscopes,” EMBO reports, vol. 19, no. 9. EMBO, 2018."},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","publisher":"EMBO","quality_controlled":"1","oa":1,"doi":"10.15252/embr.201845836","date_published":"2018-09-01T00:00:00Z","date_created":"2019-05-28T13:16:08Z","isi":1,"has_accepted_license":"1","year":"2018","day":"01","publication":"EMBO reports"},{"date_updated":"2023-09-19T15:03:16Z","citation":{"ista":"Alistarh D-A, Aspnes J, Gelashvili R. 2018. Space-optimal majority in population protocols. Proceedings of the 29th Annual ACM-SIAM Symposium on Discrete Algorithms. SODA: Symposium on Discrete Algorithms, 2221–2239.","chicago":"Alistarh, Dan-Adrian, James Aspnes, and Rati Gelashvili. “Space-Optimal Majority in Population Protocols.” In Proceedings of the 29th Annual ACM-SIAM Symposium on Discrete Algorithms, 2221–39. ACM, 2018. https://doi.org/10.1137/1.9781611975031.144.","ama":"Alistarh D-A, Aspnes J, Gelashvili R. Space-optimal majority in population protocols. In: Proceedings of the 29th Annual ACM-SIAM Symposium on Discrete Algorithms. ACM; 2018:2221-2239. doi:10.1137/1.9781611975031.144","apa":"Alistarh, D.-A., Aspnes, J., & Gelashvili, R. (2018). Space-optimal majority in population protocols. In Proceedings of the 29th Annual ACM-SIAM Symposium on Discrete Algorithms (pp. 2221–2239). New Orleans, LA, United States: ACM. https://doi.org/10.1137/1.9781611975031.144","short":"D.-A. Alistarh, J. Aspnes, R. Gelashvili, in:, Proceedings of the 29th Annual ACM-SIAM Symposium on Discrete Algorithms, ACM, 2018, pp. 2221–2239.","ieee":"D.-A. Alistarh, J. Aspnes, and R. Gelashvili, “Space-optimal majority in population protocols,” in Proceedings of the 29th Annual ACM-SIAM Symposium on Discrete Algorithms, New Orleans, LA, United States, 2018, pp. 2221–2239.","mla":"Alistarh, Dan-Adrian, et al. “Space-Optimal Majority in Population Protocols.” Proceedings of the 29th Annual ACM-SIAM Symposium on Discrete Algorithms, ACM, 2018, pp. 2221–39, doi:10.1137/1.9781611975031.144."},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","external_id":{"isi":["000483921200145"],"arxiv":["1704.04947"]},"article_processing_charge":"No","author":[{"id":"4A899BFC-F248-11E8-B48F-1D18A9856A87","first_name":"Dan-Adrian","last_name":"Alistarh","orcid":"0000-0003-3650-940X","full_name":"Alistarh, Dan-Adrian"},{"full_name":"Aspnes, James","last_name":"Aspnes","first_name":"James"},{"full_name":"Gelashvili, Rati","last_name":"Gelashvili","first_name":"Rati"}],"title":"Space-optimal majority in population protocols","department":[{"_id":"DaAl"}],"_id":"7123","conference":{"start_date":"2018-01-07","end_date":"2018-01-10","location":"New Orleans, LA, United States","name":"SODA: Symposium on Discrete Algorithms"},"type":"conference","status":"public","year":"2018","publication_status":"published","isi":1,"publication_identifier":{"isbn":["9781611975031"]},"language":[{"iso":"eng"}],"publication":"Proceedings of the 29th Annual ACM-SIAM Symposium on Discrete Algorithms","day":"30","page":"2221-2239","date_created":"2019-11-26T15:10:55Z","doi":"10.1137/1.9781611975031.144","date_published":"2018-01-30T00:00:00Z","abstract":[{"text":"Population protocols are a popular model of distributed computing, in which n agents with limited local state interact randomly, and cooperate to collectively compute global predicates. Inspired by recent developments in DNA programming, an extensive series of papers, across different communities, has examined the computability and complexity characteristics of this model. Majority, or consensus, is a central task in this model, in which agents need to collectively reach a decision as to which one of two states A or B had a higher initial count. Two metrics are important: the time that a protocol requires to stabilize to an output decision, and the state space size that each agent requires to do so. It is known that majority requires Ω(log log n) states per agent to allow for fast (poly-logarithmic time) stabilization, and that O(log2 n) states are sufficient. Thus, there is an exponential gap between the space upper and lower bounds for this problem. This paper addresses this question.\r\n\r\nOn the negative side, we provide a new lower bound of Ω(log n) states for any protocol which stabilizes in O(n1–c) expected time, for any constant c > 0. This result is conditional on monotonicity and output assumptions, satisfied by all known protocols. Technically, it represents a departure from previous lower bounds, in that it does not rely on the existence of dense configurations. Instead, we introduce a new generalized surgery technique to prove the existence of incorrect executions for any algorithm which would contradict the lower bound. Subsequently, our lower bound also applies to general initial configurations, including ones with a leader. On the positive side, we give a new algorithm for majority which uses O(log n) states, and stabilizes in O(log2 n) expected time. Central to the algorithm is a new leaderless phase clock technique, which allows agents to synchronize in phases of Θ(n log n) consecutive interactions using O(log n) states per agent, exploiting a new connection between population protocols and power-of-two-choices load balancing mechanisms. We also employ our phase clock to build a leader election algorithm with a state space of size O(log n), which stabilizes in O(log2 n) expected time.","lang":"eng"}],"oa_version":"Preprint","main_file_link":[{"url":"https://arxiv.org/abs/1704.04947","open_access":"1"}],"oa":1,"quality_controlled":"1","publisher":"ACM","month":"01"}]