--- _id: '1231' abstract: - lang: eng text: 'We study the time-and memory-complexities of the problem of computing labels of (multiple) randomly selected challenge-nodes in a directed acyclic graph. The w-bit label of a node is the hash of the labels of its parents, and the hash function is modeled as a random oracle. Specific instances of this problem underlie both proofs of space [Dziembowski et al. CRYPTO’15] as well as popular memory-hard functions like scrypt. As our main tool, we introduce the new notion of a probabilistic parallel entangled pebbling game, a new type of combinatorial pebbling game on a graph, which is closely related to the labeling game on the same graph. As a first application of our framework, we prove that for scrypt, when the underlying hash function is invoked n times, the cumulative memory complexity (CMC) (a notion recently introduced by Alwen and Serbinenko (STOC’15) to capture amortized memory-hardness for parallel adversaries) is at least Ω(w · (n/ log(n))2). This bound holds for adversaries that can store many natural functions of the labels (e.g., linear combinations), but still not arbitrary functions thereof. We then introduce and study a combinatorial quantity, and show how a sufficiently small upper bound on it (which we conjecture) extends our CMC bound for scrypt to hold against arbitrary adversaries. We also show that such an upper bound solves the main open problem for proofs-of-space protocols: namely, establishing that the time complexity of computing the label of a random node in a graph on n nodes (given an initial kw-bit state) reduces tightly to the time complexity for black pebbling on the same graph (given an initial k-node pebbling).' acknowledgement: "Joël Alwen, Chethan Kamath, and Krzysztof Pietrzak’s research is partially supported by an ERC starting grant (259668-PSPC). Vladimir Kolmogorov is partially supported by an ERC consolidator grant (616160-DOICV). Binyi Chen was partially supported by NSF grants CNS-1423566 and CNS-1514526, and a gift from the Gareatis Foundation. Stefano Tessaro was partially supported by NSF grants CNS-1423566, CNS-1528178, a Hellman Fellowship, and the Glen and Susanne Culler Chair.\r\n\r\nThis work was done in part while the authors were visiting the Simons Institute for the Theory of Computing, supported by the Simons Foundation and by the DIMACS/Simons Collaboration in Cryptography through NSF grant CNS-1523467." alternative_title: - LNCS author: - first_name: Joel F full_name: Alwen, Joel F id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87 last_name: Alwen - first_name: Binyi full_name: Chen, Binyi last_name: Chen - first_name: Chethan full_name: Kamath Hosdurg, Chethan id: 4BD3F30E-F248-11E8-B48F-1D18A9856A87 last_name: Kamath Hosdurg - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov - first_name: Krzysztof Z full_name: Pietrzak, Krzysztof Z id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87 last_name: Pietrzak orcid: 0000-0002-9139-1654 - first_name: Stefano full_name: Tessaro, Stefano last_name: Tessaro citation: ama: 'Alwen JF, Chen B, Kamath Hosdurg C, Kolmogorov V, Pietrzak KZ, Tessaro S. On the complexity of scrypt and proofs of space in the parallel random oracle model. In: Vol 9666. Springer; 2016:358-387. doi:10.1007/978-3-662-49896-5_13' apa: 'Alwen, J. F., Chen, B., Kamath Hosdurg, C., Kolmogorov, V., Pietrzak, K. Z., & Tessaro, S. (2016). On the complexity of scrypt and proofs of space in the parallel random oracle model (Vol. 9666, pp. 358–387). Presented at the EUROCRYPT: Theory and Applications of Cryptographic Techniques, Vienna, Austria: Springer. https://doi.org/10.1007/978-3-662-49896-5_13' chicago: Alwen, Joel F, Binyi Chen, Chethan Kamath Hosdurg, Vladimir Kolmogorov, Krzysztof Z Pietrzak, and Stefano Tessaro. “On the Complexity of Scrypt and Proofs of Space in the Parallel Random Oracle Model,” 9666:358–87. Springer, 2016. https://doi.org/10.1007/978-3-662-49896-5_13. ieee: 'J. F. Alwen, B. Chen, C. Kamath Hosdurg, V. Kolmogorov, K. Z. Pietrzak, and S. Tessaro, “On the complexity of scrypt and proofs of space in the parallel random oracle model,” presented at the EUROCRYPT: Theory and Applications of Cryptographic Techniques, Vienna, Austria, 2016, vol. 9666, pp. 358–387.' ista: 'Alwen JF, Chen B, Kamath Hosdurg C, Kolmogorov V, Pietrzak KZ, Tessaro S. 2016. On the complexity of scrypt and proofs of space in the parallel random oracle model. EUROCRYPT: Theory and Applications of Cryptographic Techniques, LNCS, vol. 9666, 358–387.' mla: Alwen, Joel F., et al. On the Complexity of Scrypt and Proofs of Space in the Parallel Random Oracle Model. Vol. 9666, Springer, 2016, pp. 358–87, doi:10.1007/978-3-662-49896-5_13. short: J.F. Alwen, B. Chen, C. Kamath Hosdurg, V. Kolmogorov, K.Z. Pietrzak, S. Tessaro, in:, Springer, 2016, pp. 358–387. conference: end_date: 2016-05-12 location: Vienna, Austria name: 'EUROCRYPT: Theory and Applications of Cryptographic Techniques' start_date: 2016-05-08 date_created: 2018-12-11T11:50:51Z date_published: 2016-04-28T00:00:00Z date_updated: 2021-01-12T06:49:15Z day: '28' department: - _id: KrPi - _id: VlKo doi: 10.1007/978-3-662-49896-5_13 ec_funded: 1 intvolume: ' 9666' language: - iso: eng main_file_link: - open_access: '1' url: https://eprint.iacr.org/2016/100 month: '04' oa: 1 oa_version: Submitted Version page: 358 - 387 project: - _id: 258C570E-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '259668' name: Provable Security for Physical Cryptography - _id: 25FBA906-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '616160' name: 'Discrete Optimization in Computer Vision: Theory and Practice' publication_status: published publisher: Springer publist_id: '6103' quality_controlled: '1' scopus_import: 1 status: public title: On the complexity of scrypt and proofs of space in the parallel random oracle model type: conference user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 9666 year: '2016' ... --- _id: '1353' abstract: - lang: eng text: We characterize absorption in finite idempotent algebras by means of Jónsson absorption and cube term blockers. As an application we show that it is decidable whether a given subset is an absorbing subuniverse of an algebra given by the tables of its basic operations. acknowledgement: 'Libor Barto and Alexandr Kazda were supported by the the Grant Agency of the Czech Republic, grant GACR 13-01832S. ' author: - first_name: Libor full_name: Barto, Libor last_name: Barto - first_name: Alexandr full_name: Kazda, Alexandr id: 3B32BAA8-F248-11E8-B48F-1D18A9856A87 last_name: Kazda citation: ama: Barto L, Kazda A. Deciding absorption. International Journal of Algebra and Computation. 2016;26(5):1033-1060. doi:10.1142/S0218196716500430 apa: Barto, L., & Kazda, A. (2016). Deciding absorption. International Journal of Algebra and Computation. World Scientific Publishing. https://doi.org/10.1142/S0218196716500430 chicago: Barto, Libor, and Alexandr Kazda. “Deciding Absorption.” International Journal of Algebra and Computation. World Scientific Publishing, 2016. https://doi.org/10.1142/S0218196716500430. ieee: L. Barto and A. Kazda, “Deciding absorption,” International Journal of Algebra and Computation, vol. 26, no. 5. World Scientific Publishing, pp. 1033–1060, 2016. ista: Barto L, Kazda A. 2016. Deciding absorption. International Journal of Algebra and Computation. 26(5), 1033–1060. mla: Barto, Libor, and Alexandr Kazda. “Deciding Absorption.” International Journal of Algebra and Computation, vol. 26, no. 5, World Scientific Publishing, 2016, pp. 1033–60, doi:10.1142/S0218196716500430. short: L. Barto, A. Kazda, International Journal of Algebra and Computation 26 (2016) 1033–1060. date_created: 2018-12-11T11:51:32Z date_published: 2016-07-20T00:00:00Z date_updated: 2021-01-12T06:50:06Z day: '20' department: - _id: VlKo doi: 10.1142/S0218196716500430 intvolume: ' 26' issue: '5' language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1512.07009 month: '07' oa: 1 oa_version: Preprint page: 1033 - 1060 publication: International Journal of Algebra and Computation publication_status: published publisher: World Scientific Publishing publist_id: '5893' quality_controlled: '1' scopus_import: 1 status: public title: Deciding absorption type: journal_article user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 26 year: '2016' ... --- _id: '1377' abstract: - lang: eng text: We consider the problem of minimizing the continuous valued total variation subject to different unary terms on trees and propose fast direct algorithms based on dynamic programming to solve these problems. We treat both the convex and the nonconvex case and derive worst-case complexities that are equal to or better than existing methods. We show applications to total variation based two dimensional image processing and computer vision problems based on a Lagrangian decomposition approach. The resulting algorithms are very effcient, offer a high degree of parallelism, and come along with memory requirements which are only in the order of the number of image pixels. author: - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov - first_name: Thomas full_name: Pock, Thomas last_name: Pock - first_name: Michal full_name: Rolinek, Michal id: 3CB3BC06-F248-11E8-B48F-1D18A9856A87 last_name: Rolinek citation: ama: Kolmogorov V, Pock T, Rolinek M. Total variation on a tree. SIAM Journal on Imaging Sciences. 2016;9(2):605-636. doi:10.1137/15M1010257 apa: Kolmogorov, V., Pock, T., & Rolinek, M. (2016). Total variation on a tree. SIAM Journal on Imaging Sciences. Society for Industrial and Applied Mathematics . https://doi.org/10.1137/15M1010257 chicago: Kolmogorov, Vladimir, Thomas Pock, and Michal Rolinek. “Total Variation on a Tree.” SIAM Journal on Imaging Sciences. Society for Industrial and Applied Mathematics , 2016. https://doi.org/10.1137/15M1010257. ieee: V. Kolmogorov, T. Pock, and M. Rolinek, “Total variation on a tree,” SIAM Journal on Imaging Sciences, vol. 9, no. 2. Society for Industrial and Applied Mathematics , pp. 605–636, 2016. ista: Kolmogorov V, Pock T, Rolinek M. 2016. Total variation on a tree. SIAM Journal on Imaging Sciences. 9(2), 605–636. mla: Kolmogorov, Vladimir, et al. “Total Variation on a Tree.” SIAM Journal on Imaging Sciences, vol. 9, no. 2, Society for Industrial and Applied Mathematics , 2016, pp. 605–36, doi:10.1137/15M1010257. short: V. Kolmogorov, T. Pock, M. Rolinek, SIAM Journal on Imaging Sciences 9 (2016) 605–636. date_created: 2018-12-11T11:51:40Z date_published: 2016-05-03T00:00:00Z date_updated: 2021-01-12T06:50:15Z day: '03' department: - _id: VlKo doi: 10.1137/15M1010257 ec_funded: 1 intvolume: ' 9' issue: '2' language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1502.07770 month: '05' oa: 1 oa_version: Preprint page: 605 - 636 project: - _id: 25FBA906-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '616160' name: 'Discrete Optimization in Computer Vision: Theory and Practice' publication: SIAM Journal on Imaging Sciences publication_status: published publisher: 'Society for Industrial and Applied Mathematics ' publist_id: '5834' quality_controlled: '1' scopus_import: 1 status: public title: Total variation on a tree type: journal_article user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 9 year: '2016' ... --- _id: '1612' abstract: - lang: eng text: We prove that whenever A is a 3-conservative relational structure with only binary and unary relations,then the algebra of polymorphisms of A either has no Taylor operation (i.e.,CSP(A)is NP-complete),or it generates an SD(∧) variety (i.e.,CSP(A)has bounded width). author: - first_name: Alexandr full_name: Kazda, Alexandr id: 3B32BAA8-F248-11E8-B48F-1D18A9856A87 last_name: Kazda citation: ama: Kazda A. CSP for binary conservative relational structures. Algebra Universalis. 2016;75(1):75-84. doi:10.1007/s00012-015-0358-8 apa: Kazda, A. (2016). CSP for binary conservative relational structures. Algebra Universalis. Springer. https://doi.org/10.1007/s00012-015-0358-8 chicago: Kazda, Alexandr. “CSP for Binary Conservative Relational Structures.” Algebra Universalis. Springer, 2016. https://doi.org/10.1007/s00012-015-0358-8. ieee: A. Kazda, “CSP for binary conservative relational structures,” Algebra Universalis, vol. 75, no. 1. Springer, pp. 75–84, 2016. ista: Kazda A. 2016. CSP for binary conservative relational structures. Algebra Universalis. 75(1), 75–84. mla: Kazda, Alexandr. “CSP for Binary Conservative Relational Structures.” Algebra Universalis, vol. 75, no. 1, Springer, 2016, pp. 75–84, doi:10.1007/s00012-015-0358-8. short: A. Kazda, Algebra Universalis 75 (2016) 75–84. date_created: 2018-12-11T11:53:01Z date_published: 2016-02-01T00:00:00Z date_updated: 2021-01-12T06:52:00Z day: '01' department: - _id: VlKo doi: 10.1007/s00012-015-0358-8 intvolume: ' 75' issue: '1' language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1112.1099 month: '02' oa: 1 oa_version: Preprint page: 75 - 84 publication: Algebra Universalis publication_status: published publisher: Springer publist_id: '5554' quality_controlled: '1' scopus_import: 1 status: public title: CSP for binary conservative relational structures type: journal_article user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 75 year: '2016' ... --- _id: '1193' abstract: - lang: eng text: We consider the recent formulation of the Algorithmic Lovász Local Lemma [1], [2] for finding objects that avoid "bad features", or "flaws". It extends the Moser-Tardos resampling algorithm [3] to more general discrete spaces. At each step the method picks a flaw present in the current state and "resamples" it using a "resampling oracle" provided by the user. However, it is less flexible than the Moser-Tardos method since [1], [2] require a specific flaw selection rule, whereas [3] allows an arbitrary rule (and thus can potentially be implemented more efficiently). We formulate a new "commutativity" condition, and prove that it is sufficient for an arbitrary rule to work. It also enables an efficient parallelization under an additional assumption. We then show that existing resampling oracles for perfect matchings and permutations do satisfy this condition. Finally, we generalize the precondition in [2] (in the case of symmetric potential causality graphs). This unifies special cases that previously were treated separately. acknowledgement: European Unions Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no 616160 article_number: '7782993' article_processing_charge: No author: - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov citation: ama: 'Kolmogorov V. Commutativity in the algorithmic Lovasz local lemma. In: Proceedings - Annual IEEE Symposium on Foundations of Computer Science. Vol 2016-December. IEEE; 2016. doi:10.1109/FOCS.2016.88' apa: 'Kolmogorov, V. (2016). Commutativity in the algorithmic Lovasz local lemma. In Proceedings - Annual IEEE Symposium on Foundations of Computer Science (Vol. 2016–December). New Brunswick, NJ, USA : IEEE. https://doi.org/10.1109/FOCS.2016.88' chicago: Kolmogorov, Vladimir. “Commutativity in the Algorithmic Lovasz Local Lemma.” In Proceedings - Annual IEEE Symposium on Foundations of Computer Science, Vol. 2016–December. IEEE, 2016. https://doi.org/10.1109/FOCS.2016.88. ieee: V. Kolmogorov, “Commutativity in the algorithmic Lovasz local lemma,” in Proceedings - Annual IEEE Symposium on Foundations of Computer Science, New Brunswick, NJ, USA , 2016, vol. 2016–December. ista: 'Kolmogorov V. 2016. Commutativity in the algorithmic Lovasz local lemma. Proceedings - Annual IEEE Symposium on Foundations of Computer Science. FOCS: Foundations of Computer Science vol. 2016–December, 7782993.' mla: Kolmogorov, Vladimir. “Commutativity in the Algorithmic Lovasz Local Lemma.” Proceedings - Annual IEEE Symposium on Foundations of Computer Science, vol. 2016–December, 7782993, IEEE, 2016, doi:10.1109/FOCS.2016.88. short: V. Kolmogorov, in:, Proceedings - Annual IEEE Symposium on Foundations of Computer Science, IEEE, 2016. conference: end_date: 2016-09-11 location: 'New Brunswick, NJ, USA ' name: 'FOCS: Foundations of Computer Science' start_date: 2016-09-09 date_created: 2018-12-11T11:50:38Z date_published: 2016-12-15T00:00:00Z date_updated: 2023-09-19T14:24:57Z day: '15' department: - _id: VlKo doi: 10.1109/FOCS.2016.88 ec_funded: 1 external_id: arxiv: - '1506.08547' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1506.08547v7 month: '12' oa: 1 oa_version: Preprint project: - _id: 25FBA906-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '616160' name: 'Discrete Optimization in Computer Vision: Theory and Practice' publication: Proceedings - Annual IEEE Symposium on Foundations of Computer Science publication_status: published publisher: IEEE publist_id: '6158' quality_controlled: '1' related_material: record: - id: '5975' relation: later_version status: public scopus_import: 1 status: public title: Commutativity in the algorithmic Lovasz local lemma type: conference user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 2016-December year: '2016' ... --- _id: '1794' abstract: - lang: eng text: We consider Conditional random fields (CRFs) with pattern-based potentials defined on a chain. In this model the energy of a string (labeling) (Formula presented.) is the sum of terms over intervals [i, j] where each term is non-zero only if the substring (Formula presented.) equals a prespecified pattern w. Such CRFs can be naturally applied to many sequence tagging problems. We present efficient algorithms for the three standard inference tasks in a CRF, namely computing (i) the partition function, (ii) marginals, and (iii) computing the MAP. Their complexities are respectively (Formula presented.), (Formula presented.) and (Formula presented.) where L is the combined length of input patterns, (Formula presented.) is the maximum length of a pattern, and D is the input alphabet. This improves on the previous algorithms of Ye et al. (NIPS, 2009) whose complexities are respectively (Formula presented.), (Formula presented.) and (Formula presented.), where (Formula presented.) is the number of input patterns. In addition, we give an efficient algorithm for sampling, and revisit the case of MAP with non-positive weights. acknowledgement: This work has been partially supported by the European Research Council under the European Unions Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no. 616160. author: - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov - first_name: Rustem full_name: Takhanov, Rustem id: 2CCAC26C-F248-11E8-B48F-1D18A9856A87 last_name: Takhanov citation: ama: Kolmogorov V, Takhanov R. Inference algorithms for pattern-based CRFs on sequence data. Algorithmica. 2016;76(1):17-46. doi:10.1007/s00453-015-0017-7 apa: Kolmogorov, V., & Takhanov, R. (2016). Inference algorithms for pattern-based CRFs on sequence data. Algorithmica. Springer. https://doi.org/10.1007/s00453-015-0017-7 chicago: Kolmogorov, Vladimir, and Rustem Takhanov. “Inference Algorithms for Pattern-Based CRFs on Sequence Data.” Algorithmica. Springer, 2016. https://doi.org/10.1007/s00453-015-0017-7. ieee: V. Kolmogorov and R. Takhanov, “Inference algorithms for pattern-based CRFs on sequence data,” Algorithmica, vol. 76, no. 1. Springer, pp. 17–46, 2016. ista: Kolmogorov V, Takhanov R. 2016. Inference algorithms for pattern-based CRFs on sequence data. Algorithmica. 76(1), 17–46. mla: Kolmogorov, Vladimir, and Rustem Takhanov. “Inference Algorithms for Pattern-Based CRFs on Sequence Data.” Algorithmica, vol. 76, no. 1, Springer, 2016, pp. 17–46, doi:10.1007/s00453-015-0017-7. short: V. Kolmogorov, R. Takhanov, Algorithmica 76 (2016) 17–46. date_created: 2018-12-11T11:54:02Z date_published: 2016-09-01T00:00:00Z date_updated: 2023-10-17T09:51:31Z day: '01' department: - _id: VlKo doi: 10.1007/s00453-015-0017-7 ec_funded: 1 external_id: arxiv: - '1210.0508' intvolume: ' 76' issue: '1' language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1210.0508 month: '09' oa: 1 oa_version: Preprint page: 17 - 46 project: - _id: 25FBA906-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '616160' name: 'Discrete Optimization in Computer Vision: Theory and Practice' publication: Algorithmica publication_status: published publisher: Springer publist_id: '5316' quality_controlled: '1' related_material: record: - id: '2272' relation: earlier_version status: public scopus_import: 1 status: public title: Inference algorithms for pattern-based CRFs on sequence data type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 76 year: '2016' ... --- _id: '5557' abstract: - lang: eng text: "Small synthetic discrete tomography problems.\r\nSizes are 32x32, 64z64 and 256x256.\r\nProjection angles are 2, 4, and 6.\r\nNumber of labels are 3 and 5." article_processing_charge: No author: - first_name: Paul full_name: Swoboda, Paul id: 446560C6-F248-11E8-B48F-1D18A9856A87 last_name: Swoboda citation: ama: Swoboda P. Synthetic discrete tomography problems. 2016. doi:10.15479/AT:ISTA:46 apa: Swoboda, P. (2016). Synthetic discrete tomography problems. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:46 chicago: Swoboda, Paul. “Synthetic Discrete Tomography Problems.” Institute of Science and Technology Austria, 2016. https://doi.org/10.15479/AT:ISTA:46. ieee: P. Swoboda, “Synthetic discrete tomography problems.” Institute of Science and Technology Austria, 2016. ista: Swoboda P. 2016. Synthetic discrete tomography problems, Institute of Science and Technology Austria, 10.15479/AT:ISTA:46. mla: Swoboda, Paul. Synthetic Discrete Tomography Problems. Institute of Science and Technology Austria, 2016, doi:10.15479/AT:ISTA:46. short: P. Swoboda, (2016). contributor: - contributor_type: data_collector first_name: Jan last_name: Kuske datarep_id: '46' date_created: 2018-12-12T12:31:31Z date_published: 2016-09-20T00:00:00Z date_updated: 2024-02-21T13:50:21Z day: '20' ddc: - '006' department: - _id: VlKo doi: 10.15479/AT:ISTA:46 file: - access_level: open_access checksum: aa5a16a0dc888da7186fb8fc45e88439 content_type: application/zip creator: system date_created: 2018-12-12T13:05:19Z date_updated: 2020-07-14T12:47:02Z file_id: '5645' file_name: IST-2016-46-v1+1_discrete_tomography_synthetic.zip file_size: 36058401 relation: main_file file_date_updated: 2020-07-14T12:47:02Z has_accepted_license: '1' keyword: - discrete tomography license: https://creativecommons.org/publicdomain/zero/1.0/ month: '09' oa: 1 oa_version: Published Version publisher: Institute of Science and Technology Austria status: public title: Synthetic discrete tomography problems tmp: image: /images/cc_0.png legal_code_url: https://creativecommons.org/publicdomain/zero/1.0/legalcode name: Creative Commons Public Domain Dedication (CC0 1.0) short: CC0 (1.0) type: research_data user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2016' ... --- _id: '1636' abstract: - lang: eng text: "Constraint Satisfaction Problem (CSP) is a fundamental algorithmic problem that appears in many areas of Computer Science. It can be equivalently stated as computing a homomorphism R→ΓΓ between two relational structures, e.g. between two directed graphs. Analyzing its complexity has been a prominent research direction, especially for the fixed template CSPs where the right side ΓΓ is fixed and the left side R is unconstrained.\r\n\r\nFar fewer results are known for the hybrid setting that restricts both sides simultaneously. It assumes that R belongs to a certain class of relational structures (called a structural restriction in this paper). We study which structural restrictions are effective, i.e. there exists a fixed template ΓΓ (from a certain class of languages) for which the problem is tractable when R is restricted, and NP-hard otherwise. We provide a characterization for structural restrictions that are closed under inverse homomorphisms. The criterion is based on the chromatic number of a relational structure defined in this paper; it generalizes the standard chromatic number of a graph.\r\n\r\nAs our main tool, we use the algebraic machinery developed for fixed template CSPs. To apply it to our case, we introduce a new construction called a “lifted language”. We also give a characterization for structural restrictions corresponding to minor-closed families of graphs, extend results to certain Valued CSPs (namely conservative valued languages), and state implications for (valued) CSPs with ordered variables and for the maximum weight independent set problem on some restricted families of graphs." alternative_title: - LNCS article_processing_charge: No author: - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov - first_name: Michal full_name: Rolinek, Michal id: 3CB3BC06-F248-11E8-B48F-1D18A9856A87 last_name: Rolinek - first_name: Rustem full_name: Takhanov, Rustem last_name: Takhanov citation: ama: 'Kolmogorov V, Rolinek M, Takhanov R. Effectiveness of structural restrictions for hybrid CSPs. In: 26th International Symposium. Vol 9472. Springer Nature; 2015:566-577. doi:10.1007/978-3-662-48971-0_48' apa: 'Kolmogorov, V., Rolinek, M., & Takhanov, R. (2015). Effectiveness of structural restrictions for hybrid CSPs. In 26th International Symposium (Vol. 9472, pp. 566–577). Nagoya, Japan: Springer Nature. https://doi.org/10.1007/978-3-662-48971-0_48' chicago: Kolmogorov, Vladimir, Michal Rolinek, and Rustem Takhanov. “Effectiveness of Structural Restrictions for Hybrid CSPs.” In 26th International Symposium, 9472:566–77. Springer Nature, 2015. https://doi.org/10.1007/978-3-662-48971-0_48. ieee: V. Kolmogorov, M. Rolinek, and R. Takhanov, “Effectiveness of structural restrictions for hybrid CSPs,” in 26th International Symposium, Nagoya, Japan, 2015, vol. 9472, pp. 566–577. ista: 'Kolmogorov V, Rolinek M, Takhanov R. 2015. Effectiveness of structural restrictions for hybrid CSPs. 26th International Symposium. ISAAC: International Symposium on Algorithms and Computation, LNCS, vol. 9472, 566–577.' mla: Kolmogorov, Vladimir, et al. “Effectiveness of Structural Restrictions for Hybrid CSPs.” 26th International Symposium, vol. 9472, Springer Nature, 2015, pp. 566–77, doi:10.1007/978-3-662-48971-0_48. short: V. Kolmogorov, M. Rolinek, R. Takhanov, in:, 26th International Symposium, Springer Nature, 2015, pp. 566–577. conference: end_date: 2015-12-11 location: Nagoya, Japan name: 'ISAAC: International Symposium on Algorithms and Computation' start_date: 2015-12-09 date_created: 2018-12-11T11:53:10Z date_published: 2015-12-01T00:00:00Z date_updated: 2022-02-01T15:12:35Z day: '01' department: - _id: VlKo doi: 10.1007/978-3-662-48971-0_48 ec_funded: 1 external_id: arxiv: - '1504.07067' intvolume: ' 9472' language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1504.07067 month: '12' oa: 1 oa_version: Preprint page: 566 - 577 project: - _id: 25FBA906-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '616160' name: 'Discrete Optimization in Computer Vision: Theory and Practice' publication: 26th International Symposium publication_identifier: isbn: - 978-3-662-48970-3 publication_status: published publisher: Springer Nature publist_id: '5519' quality_controlled: '1' scopus_import: '1' status: public title: Effectiveness of structural restrictions for hybrid CSPs type: conference user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9 volume: 9472 year: '2015' ... --- _id: '1841' abstract: - lang: eng text: We propose a new family of message passing techniques for MAP estimation in graphical models which we call Sequential Reweighted Message Passing (SRMP). Special cases include well-known techniques such as Min-Sum Diffusion (MSD) and a faster Sequential Tree-Reweighted Message Passing (TRW-S). Importantly, our derivation is simpler than the original derivation of TRW-S, and does not involve a decomposition into trees. This allows easy generalizations. The new family of algorithms can be viewed as a generalization of TRW-S from pairwise to higher-order graphical models. We test SRMP on several real-world problems with promising results. author: - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov citation: ama: Kolmogorov V. A new look at reweighted message passing. IEEE Transactions on Pattern Analysis and Machine Intelligence. 2015;37(5):919-930. doi:10.1109/TPAMI.2014.2363465 apa: Kolmogorov, V. (2015). A new look at reweighted message passing. IEEE Transactions on Pattern Analysis and Machine Intelligence. IEEE. https://doi.org/10.1109/TPAMI.2014.2363465 chicago: Kolmogorov, Vladimir. “A New Look at Reweighted Message Passing.” IEEE Transactions on Pattern Analysis and Machine Intelligence. IEEE, 2015. https://doi.org/10.1109/TPAMI.2014.2363465. ieee: V. Kolmogorov, “A new look at reweighted message passing,” IEEE Transactions on Pattern Analysis and Machine Intelligence, vol. 37, no. 5. IEEE, pp. 919–930, 2015. ista: Kolmogorov V. 2015. A new look at reweighted message passing. IEEE Transactions on Pattern Analysis and Machine Intelligence. 37(5), 919–930. mla: Kolmogorov, Vladimir. “A New Look at Reweighted Message Passing.” IEEE Transactions on Pattern Analysis and Machine Intelligence, vol. 37, no. 5, IEEE, 2015, pp. 919–30, doi:10.1109/TPAMI.2014.2363465. short: V. Kolmogorov, IEEE Transactions on Pattern Analysis and Machine Intelligence 37 (2015) 919–930. date_created: 2018-12-11T11:54:18Z date_published: 2015-05-01T00:00:00Z date_updated: 2021-01-12T06:53:33Z day: '01' department: - _id: VlKo doi: 10.1109/TPAMI.2014.2363465 ec_funded: 1 intvolume: ' 37' issue: '5' language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1309.5655 month: '05' oa: 1 oa_version: Preprint page: 919 - 930 project: - _id: 25FBA906-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '616160' name: 'Discrete Optimization in Computer Vision: Theory and Practice' publication: IEEE Transactions on Pattern Analysis and Machine Intelligence publication_status: published publisher: IEEE publist_id: '5261' quality_controlled: '1' scopus_import: 1 status: public title: A new look at reweighted message passing type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 37 year: '2015' ... --- _id: '1859' abstract: - lang: eng text: "Structural support vector machines (SSVMs) are amongst the best performing models for structured computer vision tasks, such as semantic image segmentation or human pose estimation. Training SSVMs, however, is computationally costly, because it requires repeated calls to a structured prediction subroutine (called \\emph{max-oracle}), which has to solve an optimization problem itself, e.g. a graph cut.\r\nIn this work, we introduce a new algorithm for SSVM training that is more efficient than earlier techniques when the max-oracle is computationally expensive, as it is frequently the case in computer vision tasks. The main idea is to (i) combine the recent stochastic Block-Coordinate Frank-Wolfe algorithm with efficient hyperplane caching, and (ii) use an automatic selection rule for deciding whether to call the exact max-oracle or to rely on an approximate one based on the cached hyperplanes.\r\nWe show experimentally that this strategy leads to faster convergence to the optimum with respect to the number of requires oracle calls, and that this translates into faster convergence with respect to the total runtime when the max-oracle is slow compared to the other steps of the algorithm. " author: - first_name: Neel full_name: Shah, Neel id: 31ABAF80-F248-11E8-B48F-1D18A9856A87 last_name: Shah - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov - first_name: Christoph full_name: Lampert, Christoph id: 40C20FD2-F248-11E8-B48F-1D18A9856A87 last_name: Lampert orcid: 0000-0001-8622-7887 citation: ama: 'Shah N, Kolmogorov V, Lampert C. A multi-plane block-coordinate Frank-Wolfe algorithm for training structural SVMs with a costly max-oracle. In: IEEE; 2015:2737-2745. doi:10.1109/CVPR.2015.7298890' apa: 'Shah, N., Kolmogorov, V., & Lampert, C. (2015). A multi-plane block-coordinate Frank-Wolfe algorithm for training structural SVMs with a costly max-oracle (pp. 2737–2745). Presented at the CVPR: Computer Vision and Pattern Recognition, Boston, MA, USA: IEEE. https://doi.org/10.1109/CVPR.2015.7298890' chicago: Shah, Neel, Vladimir Kolmogorov, and Christoph Lampert. “A Multi-Plane Block-Coordinate Frank-Wolfe Algorithm for Training Structural SVMs with a Costly Max-Oracle,” 2737–45. IEEE, 2015. https://doi.org/10.1109/CVPR.2015.7298890. ieee: 'N. Shah, V. Kolmogorov, and C. Lampert, “A multi-plane block-coordinate Frank-Wolfe algorithm for training structural SVMs with a costly max-oracle,” presented at the CVPR: Computer Vision and Pattern Recognition, Boston, MA, USA, 2015, pp. 2737–2745.' ista: 'Shah N, Kolmogorov V, Lampert C. 2015. A multi-plane block-coordinate Frank-Wolfe algorithm for training structural SVMs with a costly max-oracle. CVPR: Computer Vision and Pattern Recognition, 2737–2745.' mla: Shah, Neel, et al. A Multi-Plane Block-Coordinate Frank-Wolfe Algorithm for Training Structural SVMs with a Costly Max-Oracle. IEEE, 2015, pp. 2737–45, doi:10.1109/CVPR.2015.7298890. short: N. Shah, V. Kolmogorov, C. Lampert, in:, IEEE, 2015, pp. 2737–2745. conference: end_date: 2015-06-12 location: Boston, MA, USA name: 'CVPR: Computer Vision and Pattern Recognition' start_date: 2015-06-07 date_created: 2018-12-11T11:54:24Z date_published: 2015-06-01T00:00:00Z date_updated: 2021-01-12T06:53:40Z day: '01' department: - _id: VlKo - _id: ChLa doi: 10.1109/CVPR.2015.7298890 ec_funded: 1 language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1408.6804 month: '06' oa: 1 oa_version: Preprint page: 2737 - 2745 project: - _id: 2532554C-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '308036' name: Lifelong Learning of Visual Scene Understanding - _id: 25FBA906-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '616160' name: 'Discrete Optimization in Computer Vision: Theory and Practice' publication_status: published publisher: IEEE publist_id: '5240' quality_controlled: '1' scopus_import: 1 status: public title: A multi-plane block-coordinate Frank-Wolfe algorithm for training structural SVMs with a costly max-oracle type: conference user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2015' ...