[{"oa":1,"ec_funded":1,"date_created":"2018-12-11T11:45:40Z","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1801.06892"}],"issue":"4","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","publisher":"American Physical Society","title":"Two-photon processes based on quantum commutators","quality_controlled":"1","oa_version":"Submitted Version","abstract":[{"lang":"eng","text":"We developed a method to calculate two-photon processes in quantum mechanics that replaces the infinite summation over the intermediate states by a perturbation expansion. This latter consists of a series of commutators that involve position, momentum, and Hamiltonian quantum operators. We analyzed several single- and many-particle cases for which a closed-form solution to the perturbation expansion exists, as well as more complicated cases for which a solution is found by convergence. Throughout the article, Rayleigh and Raman scattering are taken as examples of two-photon processes. The present method provides a clear distinction between the Thomson scattering, regarded as classical scattering, and quantum contributions. Such a distinction lets us derive general results concerning light scattering. Finally, possible extensions to the developed formalism are discussed."}],"project":[{"grant_number":"291734","_id":"25681D80-B435-11E9-9278-68D0E5697425","call_identifier":"FP7","name":"International IST Postdoc Fellowship Programme"}],"article_processing_charge":"No","external_id":{"arxiv":["1801.06892"],"isi":["000430296800008"]},"scopus_import":"1","doi":"10.1103/PhysRevA.97.043842","publication":"Physical Review A - Atomic, Molecular, and Optical Physics","language":[{"iso":"eng"}],"intvolume":" 97","publist_id":"7587","author":[{"full_name":"Fratini, Filippo","first_name":"Filippo","last_name":"Fratini"},{"last_name":"Safari","first_name":"Laleh","id":"3C325E5E-F248-11E8-B48F-1D18A9856A87","full_name":"Safari, Laleh"},{"first_name":"Pedro","last_name":"Amaro","full_name":"Amaro, Pedro"},{"full_name":"Santos, José","last_name":"Santos","first_name":"José"}],"citation":{"apa":"Fratini, F., Safari, L., Amaro, P., & Santos, J. (2018). Two-photon processes based on quantum commutators. Physical Review A - Atomic, Molecular, and Optical Physics. American Physical Society. https://doi.org/10.1103/PhysRevA.97.043842","short":"F. Fratini, L. Safari, P. Amaro, J. Santos, Physical Review A - Atomic, Molecular, and Optical Physics 97 (2018).","ieee":"F. Fratini, L. Safari, P. Amaro, and J. Santos, “Two-photon processes based on quantum commutators,” Physical Review A - Atomic, Molecular, and Optical Physics, vol. 97, no. 4. American Physical Society, 2018.","chicago":"Fratini, Filippo, Laleh Safari, Pedro Amaro, and José Santos. “Two-Photon Processes Based on Quantum Commutators.” Physical Review A - Atomic, Molecular, and Optical Physics. American Physical Society, 2018. https://doi.org/10.1103/PhysRevA.97.043842.","mla":"Fratini, Filippo, et al. “Two-Photon Processes Based on Quantum Commutators.” Physical Review A - Atomic, Molecular, and Optical Physics, vol. 97, no. 4, American Physical Society, 2018, doi:10.1103/PhysRevA.97.043842.","ama":"Fratini F, Safari L, Amaro P, Santos J. Two-photon processes based on quantum commutators. Physical Review A - Atomic, Molecular, and Optical Physics. 2018;97(4). doi:10.1103/PhysRevA.97.043842","ista":"Fratini F, Safari L, Amaro P, Santos J. 2018. Two-photon processes based on quantum commutators. Physical Review A - Atomic, Molecular, and Optical Physics. 97(4)."},"status":"public","volume":97,"type":"journal_article","publication_status":"published","_id":"294","department":[{"_id":"MiLe"}],"isi":1,"month":"04","date_published":"2018-04-18T00:00:00Z","year":"2018","date_updated":"2023-09-19T10:17:56Z","day":"18"},{"day":"01","year":"2018","date_updated":"2023-09-19T10:39:09Z","month":"08","date_published":"2018-08-01T00:00:00Z","_id":"606","department":[{"_id":"JuFi"}],"isi":1,"status":"public","type":"journal_article","volume":35,"publication_status":"published","citation":{"short":"M. Duerinckx, J.L. Fischer, Annales de l’Institut Henri Poincare (C) Non Linear Analysis 35 (2018) 1267–1319.","apa":"Duerinckx, M., & Fischer, J. L. (2018). Well-posedness for mean-field evolutions arising in superconductivity. Annales de l’Institut Henri Poincare (C) Non Linear Analysis. Elsevier. https://doi.org/10.1016/j.anihpc.2017.11.004","ieee":"M. Duerinckx and J. L. Fischer, “Well-posedness for mean-field evolutions arising in superconductivity,” Annales de l’Institut Henri Poincare (C) Non Linear Analysis, vol. 35, no. 5. Elsevier, pp. 1267–1319, 2018.","chicago":"Duerinckx, Mitia, and Julian L Fischer. “Well-Posedness for Mean-Field Evolutions Arising in Superconductivity.” Annales de l’Institut Henri Poincare (C) Non Linear Analysis. Elsevier, 2018. https://doi.org/10.1016/j.anihpc.2017.11.004.","mla":"Duerinckx, Mitia, and Julian L. Fischer. “Well-Posedness for Mean-Field Evolutions Arising in Superconductivity.” Annales de l’Institut Henri Poincare (C) Non Linear Analysis, vol. 35, no. 5, Elsevier, 2018, pp. 1267–319, doi:10.1016/j.anihpc.2017.11.004.","ista":"Duerinckx M, Fischer JL. 2018. Well-posedness for mean-field evolutions arising in superconductivity. Annales de l’Institut Henri Poincare (C) Non Linear Analysis. 35(5), 1267–1319.","ama":"Duerinckx M, Fischer JL. Well-posedness for mean-field evolutions arising in superconductivity. Annales de l’Institut Henri Poincare (C) Non Linear Analysis. 2018;35(5):1267-1319. doi:10.1016/j.anihpc.2017.11.004"},"publist_id":"7199","author":[{"first_name":"Mitia","last_name":"Duerinckx","full_name":"Duerinckx, Mitia"},{"full_name":"Fischer, Julian L","orcid":"0000-0002-0479-558X","first_name":"Julian L","id":"2C12A0B0-F248-11E8-B48F-1D18A9856A87","last_name":"Fischer"}],"doi":"10.1016/j.anihpc.2017.11.004","acknowledgement":"The work of the author is supported by F.R.S.-FNRS ( Fonds de la Recherche Scientifique - FNRS ) through a Research Fellowship.\r\n\r\n","publication":"Annales de l'Institut Henri Poincare (C) Non Linear Analysis","language":[{"iso":"eng"}],"intvolume":" 35","scopus_import":"1","external_id":{"isi":["000437975500005"],"arxiv":["1607.00268"]},"page":"1267-1319","abstract":[{"lang":"eng","text":"We establish the existence of a global solution for a new family of fluid-like equations, which are obtained in certain regimes in as the mean-field evolution of the supercurrent density in a (2D section of a) type-II superconductor with pinning and with imposed electric current. We also consider general vortex-sheet initial data, and investigate the uniqueness and regularity properties of the solution. For some choice of parameters, the equation under investigation coincides with the so-called lake equation from 2D shallow water fluid dynamics, and our analysis then leads to a new existence result for rough initial data."}],"article_processing_charge":"No","publisher":"Elsevier","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","title":"Well-posedness for mean-field evolutions arising in superconductivity","oa_version":"Submitted Version","quality_controlled":"1","main_file_link":[{"url":"https://arxiv.org/abs/1607.00268","open_access":"1"}],"issue":"5","date_created":"2018-12-11T11:47:27Z","oa":1},{"month":"09","date_published":"2018-09-30T00:00:00Z","_id":"5959","department":[{"_id":"ToHe"}],"isi":1,"day":"30","year":"2018","date_updated":"2023-09-19T10:41:29Z","author":[{"last_name":"Bakhirkin","first_name":"Alexey","full_name":"Bakhirkin, Alexey"},{"first_name":"Thomas","id":"40960E6E-F248-11E8-B48F-1D18A9856A87","last_name":"Ferrere","full_name":"Ferrere, Thomas","orcid":"0000-0001-5199-3143"},{"last_name":"Henzinger","first_name":"Thomas A","id":"40876CD8-F248-11E8-B48F-1D18A9856A87","orcid":"0000−0002−2985−7724","full_name":"Henzinger, Thomas A"},{"full_name":"Nickovicl, Deian","first_name":"Deian","last_name":"Nickovicl"}],"file_date_updated":"2020-07-14T12:47:13Z","doi":"10.1109/emsoft.2018.8537203","publication":"2018 International Conference on Embedded Software","publication_identifier":{"isbn":["9781538655603"]},"language":[{"iso":"eng"}],"status":"public","type":"conference","publication_status":"published","conference":{"name":"EMSOFT: International Conference on Embedded Software","location":"Turin, Italy","start_date":"2018-09-30","end_date":"2018-10-05"},"citation":{"ieee":"A. Bakhirkin, T. Ferrere, T. A. Henzinger, and D. Nickovicl, “Keynote: The first-order logic of signals,” in 2018 International Conference on Embedded Software, Turin, Italy, 2018, pp. 1–10.","apa":"Bakhirkin, A., Ferrere, T., Henzinger, T. A., & Nickovicl, D. (2018). Keynote: The first-order logic of signals. In 2018 International Conference on Embedded Software (pp. 1–10). Turin, Italy: IEEE. https://doi.org/10.1109/emsoft.2018.8537203","short":"A. Bakhirkin, T. Ferrere, T.A. Henzinger, D. Nickovicl, in:, 2018 International Conference on Embedded Software, IEEE, 2018, pp. 1–10.","ama":"Bakhirkin A, Ferrere T, Henzinger TA, Nickovicl D. Keynote: The first-order logic of signals. In: 2018 International Conference on Embedded Software. IEEE; 2018:1-10. doi:10.1109/emsoft.2018.8537203","ista":"Bakhirkin A, Ferrere T, Henzinger TA, Nickovicl D. 2018. Keynote: The first-order logic of signals. 2018 International Conference on Embedded Software. EMSOFT: International Conference on Embedded Software, 1–10.","mla":"Bakhirkin, Alexey, et al. “Keynote: The First-Order Logic of Signals.” 2018 International Conference on Embedded Software, IEEE, 2018, pp. 1–10, doi:10.1109/emsoft.2018.8537203.","chicago":"Bakhirkin, Alexey, Thomas Ferrere, Thomas A Henzinger, and Deian Nickovicl. “Keynote: The First-Order Logic of Signals.” In 2018 International Conference on Embedded Software, 1–10. IEEE, 2018. https://doi.org/10.1109/emsoft.2018.8537203."},"has_accepted_license":"1","page":"1-10","abstract":[{"lang":"eng","text":"Formalizing properties of systems with continuous dynamics is a challenging task. In this paper, we propose a formal framework for specifying and monitoring rich temporal properties of real-valued signals. We introduce signal first-order logic (SFO) as a specification language that combines first-order logic with linear-real arithmetic and unary function symbols interpreted as piecewise-linear signals. We first show that while the satisfiability problem for SFO is undecidable, its membership and monitoring problems are decidable. We develop an offline monitoring procedure for SFO that has polynomial complexity in the size of the input trace and the specification, for a fixed number of quantifiers and function symbols. We show that the algorithm has computation time linear in the size of the input trace for the important fragment of bounded-response specifications interpreted over input traces with finite variability. We can use our results to extend signal temporal logic with first-order quantifiers over time and value parameters, while preserving its efficient monitoring. We finally demonstrate the practical appeal of our logic through a case study in the micro-electronics domain."}],"file":[{"file_size":338006,"relation":"main_file","access_level":"open_access","date_updated":"2020-07-14T12:47:13Z","creator":"dernst","checksum":"234a33ad9055b3458fcdda6af251b33a","date_created":"2020-05-14T16:01:29Z","file_name":"2018_EMSOFT_Bakhirkin.pdf","file_id":"7839","content_type":"application/pdf"}],"project":[{"_id":"25832EC2-B435-11E9-9278-68D0E5697425","grant_number":"S 11407_N23","call_identifier":"FWF","name":"Rigorous Systems Engineering"},{"name":"The Wittgenstein Prize","call_identifier":"FWF","_id":"25F42A32-B435-11E9-9278-68D0E5697425","grant_number":"Z211"}],"article_processing_charge":"No","scopus_import":"1","external_id":{"isi":["000492828500005"]},"date_created":"2019-02-13T09:19:28Z","oa":1,"ddc":["000"],"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","publisher":"IEEE","title":"Keynote: The first-order logic of signals","quality_controlled":"1","oa_version":"Published Version"},{"date_created":"2019-02-13T09:58:58Z","oa":1,"title":"The convergence of stochastic gradient descent in asynchronous shared memory","publisher":"ACM Press","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","quality_controlled":"1","oa_version":"Preprint","main_file_link":[{"url":"https://arxiv.org/abs/1803.08841","open_access":"1"}],"page":"169-178","abstract":[{"lang":"eng","text":"Stochastic Gradient Descent (SGD) is a fundamental algorithm in machine learning, representing the optimization backbone for training several classic models, from regression to neural networks. Given the recent practical focus on distributed machine learning, significant work has been dedicated to the convergence properties of this algorithm under the inconsistent and noisy updates arising from execution in a distributed environment. However, surprisingly, the convergence properties of this classic algorithm in the standard shared-memory model are still not well-understood. In this work, we address this gap, and provide new convergence bounds for lock-free concurrent stochastic gradient descent, executing in the classic asynchronous shared memory model, against a strong adaptive adversary. Our results give improved upper and lower bounds on the \"price of asynchrony'' when executing the fundamental SGD algorithm in a concurrent setting. They show that this classic optimization tool can converge faster and with a wider range of parameters than previously known under asynchronous iterations. At the same time, we exhibit a fundamental trade-off between the maximum delay in the system and the rate at which SGD can converge, which governs the set of parameters under which this algorithm can still work efficiently."}],"article_processing_charge":"No","scopus_import":"1","external_id":{"arxiv":["1803.08841"],"isi":["000458186900022"]},"author":[{"orcid":"0000-0003-3650-940X","full_name":"Alistarh, Dan-Adrian","last_name":"Alistarh","first_name":"Dan-Adrian","id":"4A899BFC-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Christopher","last_name":"De Sa","full_name":"De Sa, Christopher"},{"first_name":"Nikola H","id":"4B9D76E4-F248-11E8-B48F-1D18A9856A87","last_name":"Konstantinov","full_name":"Konstantinov, Nikola H"}],"publication":"Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC '18","doi":"10.1145/3212734.3212763","language":[{"iso":"eng"}],"publication_identifier":{"isbn":["9781450357951"]},"type":"conference","status":"public","publication_status":"published","conference":{"end_date":"2018-07-27","name":"PODC: Principles of Distributed Computing","start_date":"2018-07-23","location":"Egham, United Kingdom"},"citation":{"ista":"Alistarh D-A, De Sa C, Konstantinov NH. 2018. The convergence of stochastic gradient descent in asynchronous shared memory. Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC ’18. PODC: Principles of Distributed Computing, 169–178.","ama":"Alistarh D-A, De Sa C, Konstantinov NH. The convergence of stochastic gradient descent in asynchronous shared memory. In: Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC ’18. ACM Press; 2018:169-178. doi:10.1145/3212734.3212763","mla":"Alistarh, Dan-Adrian, et al. “The Convergence of Stochastic Gradient Descent in Asynchronous Shared Memory.” Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC ’18, ACM Press, 2018, pp. 169–78, doi:10.1145/3212734.3212763.","chicago":"Alistarh, Dan-Adrian, Christopher De Sa, and Nikola H Konstantinov. “The Convergence of Stochastic Gradient Descent in Asynchronous Shared Memory.” In Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC ’18, 169–78. ACM Press, 2018. https://doi.org/10.1145/3212734.3212763.","ieee":"D.-A. Alistarh, C. De Sa, and N. H. Konstantinov, “The convergence of stochastic gradient descent in asynchronous shared memory,” in Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC ’18, Egham, United Kingdom, 2018, pp. 169–178.","short":"D.-A. Alistarh, C. De Sa, N.H. Konstantinov, in:, Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC ’18, ACM Press, 2018, pp. 169–178.","apa":"Alistarh, D.-A., De Sa, C., & Konstantinov, N. H. (2018). The convergence of stochastic gradient descent in asynchronous shared memory. In Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC ’18 (pp. 169–178). Egham, United Kingdom: ACM Press. https://doi.org/10.1145/3212734.3212763"},"date_published":"2018-07-23T00:00:00Z","month":"07","department":[{"_id":"DaAl"}],"isi":1,"_id":"5962","day":"23","year":"2018","date_updated":"2023-09-19T10:42:53Z"},{"abstract":[{"lang":"eng","text":"A major problem for evolutionary theory is understanding the so-called open-ended nature of evolutionary change, from its definition to its origins. Open-ended evolution (OEE) refers to the unbounded increase in complexity that seems to characterize evolution on multiple scales. This property seems to be a characteristic feature of biological and technological evolution and is strongly tied to the generative potential associated with combinatorics, which allows the system to grow and expand their available state spaces. Interestingly, many complex systems presumably displaying OEE, from language to proteins, share a common statistical property: the presence of Zipf's Law. Given an inventory of basic items (such as words or protein domains) required to build more complex structures (sentences or proteins) Zipf's Law tells us that most of these elements are rare whereas a few of them are extremely common. Using algorithmic information theory, in this paper we provide a fundamental definition for open-endedness, which can be understood as postulates. Its statistical counterpart, based on standard Shannon information theory, has the structure of a variational problem which is shown to lead to Zipf's Law as the expected consequence of an evolutionary process displaying OEE. We further explore the problem of information conservation through an OEE process and we conclude that statistical information (standard Shannon information) is not conserved, resulting in the paradoxical situation in which the increase of information content has the effect of erasing itself. We prove that this paradox is solved if we consider non-statistical forms of information. This last result implies that standard information theory may not be a suitable theoretical framework to explore the persistence and increase of the information content in OEE systems."}],"article_processing_charge":"No","scopus_import":"1","external_id":{"isi":["000456783800002"],"arxiv":["1612.01605"]},"date_created":"2019-01-20T22:59:19Z","oa":1,"publisher":"Royal Society Publishing","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","title":"Zipf's Law, unbounded complexity and open-ended evolution","oa_version":"Preprint","quality_controlled":"1","main_file_link":[{"url":"https://arxiv.org/abs/1612.01605","open_access":"1"}],"issue":"149","month":"12","date_published":"2018-12-12T00:00:00Z","article_number":"20180395","_id":"5860","isi":1,"department":[{"_id":"EdHa"}],"day":"12","year":"2018","date_updated":"2023-09-19T10:40:38Z","author":[{"last_name":"Corominas-Murtra","first_name":"Bernat","id":"43BE2298-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0001-9806-5643","full_name":"Corominas-Murtra, Bernat"},{"full_name":"Seoane, Luís F.","first_name":"Luís F.","last_name":"Seoane"},{"first_name":"Ricard","last_name":"Solé","full_name":"Solé, Ricard"}],"doi":"10.1098/rsif.2018.0395","publication":"Journal of the Royal Society Interface","publication_identifier":{"issn":["17425689"]},"intvolume":" 15","language":[{"iso":"eng"}],"status":"public","type":"journal_article","volume":15,"publication_status":"published","citation":{"ista":"Corominas-Murtra B, Seoane LF, Solé R. 2018. Zipf’s Law, unbounded complexity and open-ended evolution. Journal of the Royal Society Interface. 15(149), 20180395.","ama":"Corominas-Murtra B, Seoane LF, Solé R. Zipf’s Law, unbounded complexity and open-ended evolution. Journal of the Royal Society Interface. 2018;15(149). doi:10.1098/rsif.2018.0395","chicago":"Corominas-Murtra, Bernat, Luís F. Seoane, and Ricard Solé. “Zipf’s Law, Unbounded Complexity and Open-Ended Evolution.” Journal of the Royal Society Interface. Royal Society Publishing, 2018. https://doi.org/10.1098/rsif.2018.0395.","mla":"Corominas-Murtra, Bernat, et al. “Zipf’s Law, Unbounded Complexity and Open-Ended Evolution.” Journal of the Royal Society Interface, vol. 15, no. 149, 20180395, Royal Society Publishing, 2018, doi:10.1098/rsif.2018.0395.","ieee":"B. Corominas-Murtra, L. F. Seoane, and R. Solé, “Zipf’s Law, unbounded complexity and open-ended evolution,” Journal of the Royal Society Interface, vol. 15, no. 149. Royal Society Publishing, 2018.","apa":"Corominas-Murtra, B., Seoane, L. F., & Solé, R. (2018). Zipf’s Law, unbounded complexity and open-ended evolution. Journal of the Royal Society Interface. Royal Society Publishing. https://doi.org/10.1098/rsif.2018.0395","short":"B. Corominas-Murtra, L.F. Seoane, R. Solé, Journal of the Royal Society Interface 15 (2018)."}},{"citation":{"ista":"Rohou S, Franek P, Aubry C, Jaulin L. 2018. Proving the existence of loops in robot trajectories. The International Journal of Robotics Research. 37(12), 1500–1516.","ama":"Rohou S, Franek P, Aubry C, Jaulin L. Proving the existence of loops in robot trajectories. The International Journal of Robotics Research. 2018;37(12):1500-1516. doi:10.1177/0278364918808367","chicago":"Rohou, Simon, Peter Franek, Clément Aubry, and Luc Jaulin. “Proving the Existence of Loops in Robot Trajectories.” The International Journal of Robotics Research. SAGE Publications, 2018. https://doi.org/10.1177/0278364918808367.","mla":"Rohou, Simon, et al. “Proving the Existence of Loops in Robot Trajectories.” The International Journal of Robotics Research, vol. 37, no. 12, SAGE Publications, 2018, pp. 1500–16, doi:10.1177/0278364918808367.","ieee":"S. Rohou, P. Franek, C. Aubry, and L. Jaulin, “Proving the existence of loops in robot trajectories,” The International Journal of Robotics Research, vol. 37, no. 12. SAGE Publications, pp. 1500–1516, 2018.","apa":"Rohou, S., Franek, P., Aubry, C., & Jaulin, L. (2018). Proving the existence of loops in robot trajectories. The International Journal of Robotics Research. SAGE Publications. https://doi.org/10.1177/0278364918808367","short":"S. Rohou, P. Franek, C. Aubry, L. Jaulin, The International Journal of Robotics Research 37 (2018) 1500–1516."},"publication_status":"published","status":"public","volume":37,"type":"journal_article","publication_identifier":{"eissn":["1741-3176"],"issn":["0278-3649"]},"intvolume":" 37","language":[{"iso":"eng"}],"doi":"10.1177/0278364918808367","publication":"The International Journal of Robotics Research","author":[{"full_name":"Rohou, Simon","last_name":"Rohou","first_name":"Simon"},{"full_name":"Franek, Peter","orcid":"0000-0001-8878-8397","first_name":"Peter","id":"473294AE-F248-11E8-B48F-1D18A9856A87","last_name":"Franek"},{"full_name":"Aubry, Clément","first_name":"Clément","last_name":"Aubry"},{"first_name":"Luc","last_name":"Jaulin","full_name":"Jaulin, Luc"}],"date_updated":"2023-09-19T10:41:59Z","year":"2018","day":"24","_id":"5960","department":[{"_id":"UlWa"}],"isi":1,"month":"10","date_published":"2018-10-24T00:00:00Z","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1712.01341"}],"issue":"12","oa_version":"Preprint","quality_controlled":"1","publisher":"SAGE Publications","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","title":"Proving the existence of loops in robot trajectories","oa":1,"date_created":"2019-02-13T09:36:20Z","external_id":{"arxiv":["1712.01341"],"isi":["000456881100004"]},"scopus_import":"1","article_processing_charge":"No","abstract":[{"lang":"eng","text":"In this paper we present a reliable method to verify the existence of loops along the uncertain trajectory of a robot, based on proprioceptive measurements only, within a bounded-error context. The loop closure detection is one of the key points in simultaneous localization and mapping (SLAM) methods, especially in homogeneous environments with difficult scenes recognitions. The proposed approach is generic and could be coupled with conventional SLAM algorithms to reliably reduce their computing burden, thus improving the localization and mapping processes in the most challenging environments such as unexplored underwater extents. To prove that a robot performed a loop whatever the uncertainties in its evolution, we employ the notion of topological degree that originates in the field of differential topology. We show that a verification tool based on the topological degree is an optimal method for proving robot loops. This is demonstrated both on datasets from real missions involving autonomous underwater vehicles and by a mathematical discussion."}],"page":"1500-1516"},{"external_id":{"arxiv":["1808.04155"],"isi":["000458186900048"]},"scopus_import":"1","article_processing_charge":"No","page":"377-386","abstract":[{"text":"There has been significant progress in understanding the parallelism inherent to iterative sequential algorithms: for many classic algorithms, the depth of the dependence structure is now well understood, and scheduling techniques have been developed to exploit this shallow dependence structure for efficient parallel implementations. A related, applied research strand has studied methods by which certain iterative task-based algorithms can be efficiently parallelized via relaxed concurrent priority schedulers. These allow for high concurrency when inserting and removing tasks, at the cost of executing superfluous work due to the relaxed semantics of the scheduler. In this work, we take a step towards unifying these two research directions, by showing that there exists a family of relaxed priority schedulers that can efficiently and deterministically execute classic iterative algorithms such as greedy maximal independent set (MIS) and matching. Our primary result shows that, given a randomized scheduler with an expected relaxation factor of k in terms of the maximum allowed priority inversions on a task, and any graph on n vertices, the scheduler is able to execute greedy MIS with only an additive factor of \\poly(k) expected additional iterations compared to an exact (but not scalable) scheduler. This counter-intuitive result demonstrates that the overhead of relaxation when computing MIS is not dependent on the input size or structure of the input graph. Experimental results show that this overhead can be clearly offset by the gain in performance due to the highly scalable scheduler. In sum, we present an efficient method to deterministically parallelize iterative sequential algorithms, with provable runtime guarantees in terms of the number of executed tasks to completion.","lang":"eng"}],"main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1808.04155"}],"oa_version":"Preprint","quality_controlled":"1","title":"Relaxed schedulers can efficiently parallelize iterative algorithms","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","publisher":"ACM Press","oa":1,"date_created":"2019-02-13T10:03:25Z","date_updated":"2023-09-19T10:43:21Z","year":"2018","day":"23","department":[{"_id":"DaAl"}],"isi":1,"_id":"5963","date_published":"2018-07-23T00:00:00Z","month":"07","citation":{"ama":"Alistarh D-A, Brown TA, Kopinsky J, Nadiradze G. Relaxed schedulers can efficiently parallelize iterative algorithms. In: Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC ’18. ACM Press; 2018:377-386. doi:10.1145/3212734.3212756","ista":"Alistarh D-A, Brown TA, Kopinsky J, Nadiradze G. 2018. Relaxed schedulers can efficiently parallelize iterative algorithms. Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC ’18. PODC: Principles of Distributed Computing, 377–386.","mla":"Alistarh, Dan-Adrian, et al. “Relaxed Schedulers Can Efficiently Parallelize Iterative Algorithms.” Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC ’18, ACM Press, 2018, pp. 377–86, doi:10.1145/3212734.3212756.","chicago":"Alistarh, Dan-Adrian, Trevor A Brown, Justin Kopinsky, and Giorgi Nadiradze. “Relaxed Schedulers Can Efficiently Parallelize Iterative Algorithms.” In Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC ’18, 377–86. ACM Press, 2018. https://doi.org/10.1145/3212734.3212756.","ieee":"D.-A. Alistarh, T. A. Brown, J. Kopinsky, and G. Nadiradze, “Relaxed schedulers can efficiently parallelize iterative algorithms,” in Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC ’18, Egham, United Kingdom, 2018, pp. 377–386.","short":"D.-A. Alistarh, T.A. Brown, J. Kopinsky, G. Nadiradze, in:, Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC ’18, ACM Press, 2018, pp. 377–386.","apa":"Alistarh, D.-A., Brown, T. A., Kopinsky, J., & Nadiradze, G. (2018). Relaxed schedulers can efficiently parallelize iterative algorithms. In Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC ’18 (pp. 377–386). Egham, United Kingdom: ACM Press. https://doi.org/10.1145/3212734.3212756"},"conference":{"name":"PODC: Principles of Distributed Computing","location":"Egham, United Kingdom","start_date":"2018-07-23","end_date":"2018-07-27"},"publication_status":"published","type":"conference","status":"public","language":[{"iso":"eng"}],"publication_identifier":{"isbn":["9781450357951"]},"publication":"Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing - PODC '18","doi":"10.1145/3212734.3212756","author":[{"last_name":"Alistarh","first_name":"Dan-Adrian","id":"4A899BFC-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0003-3650-940X","full_name":"Alistarh, Dan-Adrian"},{"full_name":"Brown, Trevor A","id":"3569F0A0-F248-11E8-B48F-1D18A9856A87","first_name":"Trevor A","last_name":"Brown"},{"full_name":"Kopinsky, Justin","first_name":"Justin","last_name":"Kopinsky"},{"full_name":"Nadiradze, Giorgi","last_name":"Nadiradze","first_name":"Giorgi"}]},{"external_id":{"arxiv":["1804.01018"],"isi":["000545269600016"]},"scopus_import":"1","article_processing_charge":"No","abstract":[{"text":"Relaxed concurrent data structures have become increasingly popular, due to their scalability in graph processing and machine learning applications (\\citeNguyen13, gonzalez2012powergraph ). Despite considerable interest, there exist families of natural, high performing randomized relaxed concurrent data structures, such as the popular MultiQueue~\\citeMQ pattern for implementing relaxed priority queue data structures, for which no guarantees are known in the concurrent setting~\\citeAKLN17. Our main contribution is in showing for the first time that, under a set of analytic assumptions, a family of relaxed concurrent data structures, including variants of MultiQueues, but also a new approximate counting algorithm we call the MultiCounter, provides strong probabilistic guarantees on the degree of relaxation with respect to the sequential specification, in arbitrary concurrent executions. We formalize these guarantees via a new correctness condition called distributional linearizability, tailored to concurrent implementations with randomized relaxations. Our result is based on a new analysis of an asynchronous variant of the classic power-of-two-choices load balancing algorithm, in which placement choices can be based on inconsistent, outdated information (this result may be of independent interest). We validate our results empirically, showing that the MultiCounter algorithm can implement scalable relaxed timestamps.","lang":"eng"}],"page":"133-142","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1804.01018"}],"quality_controlled":"1","oa_version":"Preprint","title":"Distributionally linearizable data structures","publisher":"ACM Press","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","oa":1,"date_created":"2019-02-13T10:17:19Z","date_updated":"2023-09-19T10:44:13Z","year":"2018","related_material":{"record":[{"status":"public","relation":"dissertation_contains","id":"10429"}]},"day":"16","isi":1,"department":[{"_id":"DaAl"}],"_id":"5965","date_published":"2018-07-16T00:00:00Z","month":"07","citation":{"apa":"Alistarh, D.-A., Brown, T. A., Kopinsky, J., Li, J. Z., & Nadiradze, G. (2018). Distributionally linearizable data structures. In Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA ’18 (pp. 133–142). Vienna, Austria: ACM Press. https://doi.org/10.1145/3210377.3210411","short":"D.-A. Alistarh, T.A. Brown, J. Kopinsky, J.Z. Li, G. Nadiradze, in:, Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA ’18, ACM Press, 2018, pp. 133–142.","ieee":"D.-A. Alistarh, T. A. Brown, J. Kopinsky, J. Z. Li, and G. Nadiradze, “Distributionally linearizable data structures,” in Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA ’18, Vienna, Austria, 2018, pp. 133–142.","mla":"Alistarh, Dan-Adrian, et al. “Distributionally Linearizable Data Structures.” Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA ’18, ACM Press, 2018, pp. 133–42, doi:10.1145/3210377.3210411.","chicago":"Alistarh, Dan-Adrian, Trevor A Brown, Justin Kopinsky, Jerry Z. Li, and Giorgi Nadiradze. “Distributionally Linearizable Data Structures.” In Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA ’18, 133–42. ACM Press, 2018. https://doi.org/10.1145/3210377.3210411.","ista":"Alistarh D-A, Brown TA, Kopinsky J, Li JZ, Nadiradze G. 2018. Distributionally linearizable data structures. Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA ’18. SPAA: Symposium on Parallelism in Algorithms and Architectures, 133–142.","ama":"Alistarh D-A, Brown TA, Kopinsky J, Li JZ, Nadiradze G. Distributionally linearizable data structures. In: Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA ’18. ACM Press; 2018:133-142. doi:10.1145/3210377.3210411"},"publication_status":"published","conference":{"end_date":"2018-07-18","name":"SPAA: Symposium on Parallelism in Algorithms and Architectures","location":"Vienna, Austria","start_date":"2018-07-16"},"type":"conference","status":"public","language":[{"iso":"eng"}],"publication_identifier":{"isbn":["9781450357999"]},"publication":"Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA '18","doi":"10.1145/3210377.3210411","author":[{"orcid":"0000-0003-3650-940X","full_name":"Alistarh, Dan-Adrian","last_name":"Alistarh","first_name":"Dan-Adrian","id":"4A899BFC-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Trevor A","id":"3569F0A0-F248-11E8-B48F-1D18A9856A87","last_name":"Brown","full_name":"Brown, Trevor A"},{"full_name":"Kopinsky, Justin","first_name":"Justin","last_name":"Kopinsky"},{"last_name":"Li","first_name":"Jerry Z.","full_name":"Li, Jerry Z."},{"first_name":"Giorgi","last_name":"Nadiradze","full_name":"Nadiradze, Giorgi"}]},{"doi":"10.1145/3219166.3219198","publication":"Proceedings of the 2018 ACM Conference on Economics and Computation - EC '18","publication_identifier":{"isbn":["9781450358293"]},"language":[{"iso":"eng"}],"author":[{"full_name":"Hansen, Kristoffer Arnsfelt","last_name":"Hansen","first_name":"Kristoffer Arnsfelt"},{"last_name":"Ibsen-Jensen","first_name":"Rasmus","id":"3B699956-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0003-4783-0389","full_name":"Ibsen-Jensen, Rasmus"},{"last_name":"Neyman","first_name":"Abraham","full_name":"Neyman, Abraham"}],"file_date_updated":"2020-07-14T12:47:14Z","citation":{"ama":"Hansen KA, Ibsen-Jensen R, Neyman A. The Big Match with a clock and a bit of memory. In: Proceedings of the 2018 ACM Conference on Economics and Computation - EC ’18. ACM Press; 2018:149-150. doi:10.1145/3219166.3219198","ista":"Hansen KA, Ibsen-Jensen R, Neyman A. 2018. The Big Match with a clock and a bit of memory. Proceedings of the 2018 ACM Conference on Economics and Computation - EC ’18. EC: Conference on Economics and Computation, 149–150.","mla":"Hansen, Kristoffer Arnsfelt, et al. “The Big Match with a Clock and a Bit of Memory.” Proceedings of the 2018 ACM Conference on Economics and Computation - EC ’18, ACM Press, 2018, pp. 149–50, doi:10.1145/3219166.3219198.","chicago":"Hansen, Kristoffer Arnsfelt, Rasmus Ibsen-Jensen, and Abraham Neyman. “The Big Match with a Clock and a Bit of Memory.” In Proceedings of the 2018 ACM Conference on Economics and Computation - EC ’18, 149–50. ACM Press, 2018. https://doi.org/10.1145/3219166.3219198.","ieee":"K. A. Hansen, R. Ibsen-Jensen, and A. Neyman, “The Big Match with a clock and a bit of memory,” in Proceedings of the 2018 ACM Conference on Economics and Computation - EC ’18, Ithaca, NY, United States, 2018, pp. 149–150.","short":"K.A. Hansen, R. Ibsen-Jensen, A. Neyman, in:, Proceedings of the 2018 ACM Conference on Economics and Computation - EC ’18, ACM Press, 2018, pp. 149–150.","apa":"Hansen, K. A., Ibsen-Jensen, R., & Neyman, A. (2018). The Big Match with a clock and a bit of memory. In Proceedings of the 2018 ACM Conference on Economics and Computation - EC ’18 (pp. 149–150). Ithaca, NY, United States: ACM Press. https://doi.org/10.1145/3219166.3219198"},"status":"public","type":"conference","publication_status":"published","conference":{"name":"EC: Conference on Economics and Computation","start_date":"2018-06-18","location":"Ithaca, NY, United States","end_date":"2018-06-22"},"_id":"5967","department":[{"_id":"KrCh"}],"isi":1,"month":"06","date_published":"2018-06-18T00:00:00Z","year":"2018","date_updated":"2023-09-19T10:45:15Z","day":"18","oa":1,"ddc":["000"],"date_created":"2019-02-13T10:31:41Z","publisher":"ACM Press","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","title":"The Big Match with a clock and a bit of memory","quality_controlled":"1","oa_version":"Submitted Version","has_accepted_license":"1","page":"149-150","abstract":[{"lang":"eng","text":"The Big Match is a multi-stage two-player game. In each stage Player 1 hides one or two pebbles in his hand, and his opponent has to guess that number; Player 1 loses a point if Player 2 is correct, and otherwise he wins a point. As soon as Player 1 hides one pebble, the players cannot change their choices in any future stage.\r\nBlackwell and Ferguson (1968) give an ε-optimal strategy for Player 1 that hides, in each stage, one pebble with a probability that depends on the entire past history. Any strategy that depends just on the clock or on a finite memory is worthless. The long-standing natural open problem has been whether every strategy that depends just on the clock and a finite memory is worthless. We prove that there is such a strategy that is ε-optimal. In fact, we show that just two states of memory are sufficient.\r\n"}],"file":[{"file_id":"7054","content_type":"application/pdf","date_created":"2019-11-19T08:24:24Z","file_name":"2018_EC18_Hansen.pdf","checksum":"bb52683e349cfd864f4769a8f38f2798","creator":"dernst","date_updated":"2020-07-14T12:47:14Z","access_level":"open_access","relation":"main_file","file_size":302539}],"article_processing_charge":"No","external_id":{"isi":["000492755100020"]},"scopus_import":"1"},{"article_processing_charge":"No","abstract":[{"lang":"eng","text":"The transactional conflict problem arises in transactional systems whenever two or more concurrent transactions clash on a data item. While the standard solution to such conflicts is to immediately abort one of the transactions, some practical systems consider the alternative of delaying conflict resolution for a short interval, which may allow one of the transactions to commit. The challenge in the transactional conflict problem is to choose the optimal length of this delay interval so as to minimize the overall running time penalty for the conflicting transactions. In this paper, we propose a family of optimal online algorithms for the transactional conflict problem. Specifically, we consider variants of this problem which arise in different implementations of transactional systems, namely \"requestor wins'' and \"requestor aborts'' implementations: in the former, the recipient of a coherence request is aborted, whereas in the latter, it is the requestor which has to abort. Both strategies are implemented by real systems. We show that the requestor aborts case can be reduced to a classic instance of the ski rental problem, while the requestor wins case leads to a new version of this classical problem, for which we derive optimal deterministic and randomized algorithms. Moreover, we prove that, under a simplified adversarial model, our algorithms are constant-competitive with the offline optimum in terms of throughput. We validate our algorithmic results empirically through a hardware simulation of hardware transactional memory (HTM), showing that our algorithms can lead to non-trivial performance improvements for classic concurrent data structures."}],"page":"383-392","external_id":{"isi":["000545269600046"],"arxiv":["1804.00947"]},"scopus_import":"1","oa":1,"date_created":"2019-02-13T10:26:07Z","main_file_link":[{"url":"https://arxiv.org/abs/1804.00947","open_access":"1"}],"oa_version":"Preprint","quality_controlled":"1","title":"The transactional conflict problem","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","publisher":"ACM Press","department":[{"_id":"DaAl"}],"isi":1,"_id":"5966","date_published":"2018-07-16T00:00:00Z","month":"07","date_updated":"2023-09-19T10:44:49Z","year":"2018","day":"16","language":[{"iso":"eng"}],"publication_identifier":{"isbn":["9781450357999"]},"publication":"Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA '18","doi":"10.1145/3210377.3210406","author":[{"orcid":"0000-0003-3650-940X","full_name":"Alistarh, Dan-Adrian","last_name":"Alistarh","first_name":"Dan-Adrian","id":"4A899BFC-F248-11E8-B48F-1D18A9856A87"},{"full_name":"Haider, Syed Kamran","last_name":"Haider","first_name":"Syed Kamran"},{"last_name":"Kübler","first_name":"Raphael","full_name":"Kübler, Raphael"},{"first_name":"Giorgi","last_name":"Nadiradze","full_name":"Nadiradze, Giorgi"}],"citation":{"short":"D.-A. Alistarh, S.K. Haider, R. Kübler, G. Nadiradze, in:, Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA ’18, ACM Press, 2018, pp. 383–392.","apa":"Alistarh, D.-A., Haider, S. K., Kübler, R., & Nadiradze, G. (2018). The transactional conflict problem. In Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA ’18 (pp. 383–392). Vienna, Austria: ACM Press. https://doi.org/10.1145/3210377.3210406","ieee":"D.-A. Alistarh, S. K. Haider, R. Kübler, and G. Nadiradze, “The transactional conflict problem,” in Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA ’18, Vienna, Austria, 2018, pp. 383–392.","mla":"Alistarh, Dan-Adrian, et al. “The Transactional Conflict Problem.” Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA ’18, ACM Press, 2018, pp. 383–92, doi:10.1145/3210377.3210406.","chicago":"Alistarh, Dan-Adrian, Syed Kamran Haider, Raphael Kübler, and Giorgi Nadiradze. “The Transactional Conflict Problem.” In Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA ’18, 383–92. ACM Press, 2018. https://doi.org/10.1145/3210377.3210406.","ama":"Alistarh D-A, Haider SK, Kübler R, Nadiradze G. The transactional conflict problem. In: Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA ’18. ACM Press; 2018:383-392. doi:10.1145/3210377.3210406","ista":"Alistarh D-A, Haider SK, Kübler R, Nadiradze G. 2018. The transactional conflict problem. Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA ’18. SPAA: Symposium on Parallelism in Algorithms and Architectures, 383–392."},"conference":{"end_date":"2018-07-18","name":"SPAA: Symposium on Parallelism in Algorithms and Architectures","start_date":"2018-07-16","location":"Vienna, Austria"},"publication_status":"published","type":"conference","status":"public"}]