--- _id: '2270' abstract: - lang: eng text: "Representation languages for coalitional games are a key research area in algorithmic game theory. There is an inher-\r\nent tradeoff between how general a language is, allowing it to capture more elaborate games, and how hard \ it is computationally to optimize and solve such games. One prominent such \ language is the simple yet expressive\r\nWeighted Graph Games (WGGs) representation (Deng and Papadimitriou 1994), which maintains knowledge about synergies between agents in the form of an edge weighted graph. We consider the problem of finding \ the optimal coalition structure in WGGs. The agents in such games are vertices in a graph, and the value of a coalition is the sum of the weights of the edges present between coalition members. The optimal coalition structure is a partition of the agents to coalitions, that maximizes the sum of utilities obtained by the coalitions. We show that finding the optimal coalition structure is not only hard for general graphs, but is also intractable for restricted families such as planar graphs which are amenable for many other combinatorial problems. \ We then provide algorithms with constant factor approximations for planar, minorfree and bounded degree graphs." author: - first_name: Yoram full_name: Bachrach, Yoram last_name: Bachrach - first_name: Pushmeet full_name: Kohli, Pushmeet last_name: Kohli - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov - first_name: Morteza full_name: Zadimoghaddam, Morteza last_name: Zadimoghaddam citation: ama: 'Bachrach Y, Kohli P, Kolmogorov V, Zadimoghaddam M. Optimal Coalition Structures in Cooperative Graph Games. In: AAAI Press; 2013:81-87.' apa: 'Bachrach, Y., Kohli, P., Kolmogorov, V., & Zadimoghaddam, M. (2013). Optimal Coalition Structures in Cooperative Graph Games (pp. 81–87). Presented at the AAAI: Conference on Artificial Intelligence, Bellevue, WA, United States: AAAI Press.' chicago: Bachrach, Yoram, Pushmeet Kohli, Vladimir Kolmogorov, and Morteza Zadimoghaddam. “Optimal Coalition Structures in Cooperative Graph Games,” 81–87. AAAI Press, 2013. ieee: 'Y. Bachrach, P. Kohli, V. Kolmogorov, and M. Zadimoghaddam, “Optimal Coalition Structures in Cooperative Graph Games,” presented at the AAAI: Conference on Artificial Intelligence, Bellevue, WA, United States, 2013, pp. 81–87.' ista: 'Bachrach Y, Kohli P, Kolmogorov V, Zadimoghaddam M. 2013. Optimal Coalition Structures in Cooperative Graph Games. AAAI: Conference on Artificial Intelligence, 81–87.' mla: Bachrach, Yoram, et al. Optimal Coalition Structures in Cooperative Graph Games. AAAI Press, 2013, pp. 81–87. short: Y. Bachrach, P. Kohli, V. Kolmogorov, M. Zadimoghaddam, in:, AAAI Press, 2013, pp. 81–87. conference: end_date: 2013-07-18 location: Bellevue, WA, United States name: 'AAAI: Conference on Artificial Intelligence' start_date: 2013-07-14 date_created: 2018-12-11T11:56:41Z date_published: 2013-12-31T00:00:00Z date_updated: 2021-01-12T06:56:25Z day: '31' department: - _id: VlKo external_id: arxiv: - '1108.5248' language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1108.5248 month: '12' oa: 1 oa_version: None page: 81-87 publication_status: published publisher: AAAI Press publist_id: '4674' quality_controlled: '1' status: public title: Optimal Coalition Structures in Cooperative Graph Games type: conference user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2013' ... --- _id: '2273' 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 Diusion (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. We present such a generalization for the case of higher-order graphical models, and test it on several real-world problems with promising results. author: - first_name: Vladimir full_name: Vladimir Kolmogorov id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov citation: ama: Kolmogorov V. Reweighted Message Passing Revisited. IST Austria; 2013. apa: Kolmogorov, V. (2013). Reweighted message passing revisited. IST Austria. chicago: Kolmogorov, Vladimir. Reweighted Message Passing Revisited. IST Austria, 2013. ieee: V. Kolmogorov, Reweighted message passing revisited. IST Austria, 2013. ista: Kolmogorov V. 2013. Reweighted message passing revisited, IST Austria,p. mla: Kolmogorov, Vladimir. Reweighted Message Passing Revisited. IST Austria, 2013. short: V. Kolmogorov, Reweighted Message Passing Revisited, IST Austria, 2013. date_created: 2018-12-11T11:56:42Z date_published: 2013-09-22T00:00:00Z date_updated: 2019-01-24T13:07:32Z day: '22' department: - _id: VlKo extern: 0 main_file_link: - open_access: '1' url: http://arxiv.org/abs/1309.5655 month: '09' oa: 1 publication_status: published publisher: IST Austria publist_id: '4671' quality_controlled: 0 status: public title: Reweighted message passing revisited type: report year: '2013' ... --- _id: '2276' abstract: - lang: eng text: The problem of minimizing the Potts energy function frequently occurs in computer vision applications. One way to tackle this NP-hard problem was proposed by Kovtun [19, 20]. It identifies a part of an optimal solution by running k maxflow computations, where k is the number of labels. The number of “labeled” pixels can be significant in some applications, e.g. 50-93% in our tests for stereo. We show how to reduce the runtime to O (log k) maxflow computations (or one parametric maxflow computation). Furthermore, the output of our algorithm allows to speed-up the subsequent alpha expansion for the unlabeled part, or can be used as it is for time-critical applications. To derive our technique, we generalize the algorithm of Felzenszwalb et al. [7] for Tree Metrics . We also show a connection to k-submodular functions from combinatorial optimization, and discuss k-submodular relaxations for general energy functions. author: - first_name: Igor full_name: Gridchyn, Igor id: 4B60654C-F248-11E8-B48F-1D18A9856A87 last_name: Gridchyn - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov citation: ama: 'Gridchyn I, Kolmogorov V. Potts model, parametric maxflow and k-submodular functions. In: IEEE; 2013:2320-2327. doi:10.1109/ICCV.2013.288' apa: 'Gridchyn, I., & Kolmogorov, V. (2013). Potts model, parametric maxflow and k-submodular functions (pp. 2320–2327). Presented at the ICCV: International Conference on Computer Vision, Sydney, Australia: IEEE. https://doi.org/10.1109/ICCV.2013.288' chicago: Gridchyn, Igor, and Vladimir Kolmogorov. “Potts Model, Parametric Maxflow and k-Submodular Functions,” 2320–27. IEEE, 2013. https://doi.org/10.1109/ICCV.2013.288. ieee: 'I. Gridchyn and V. Kolmogorov, “Potts model, parametric maxflow and k-submodular functions,” presented at the ICCV: International Conference on Computer Vision, Sydney, Australia, 2013, pp. 2320–2327.' ista: 'Gridchyn I, Kolmogorov V. 2013. Potts model, parametric maxflow and k-submodular functions. ICCV: International Conference on Computer Vision, 2320–2327.' mla: Gridchyn, Igor, and Vladimir Kolmogorov. Potts Model, Parametric Maxflow and k-Submodular Functions. IEEE, 2013, pp. 2320–27, doi:10.1109/ICCV.2013.288. short: I. Gridchyn, V. Kolmogorov, in:, IEEE, 2013, pp. 2320–2327. conference: end_date: 2013-12-08 location: Sydney, Australia name: 'ICCV: International Conference on Computer Vision' start_date: 2013-12-01 date_created: 2018-12-11T11:56:43Z date_published: 2013-12-01T00:00:00Z date_updated: 2021-01-12T06:56:28Z day: '01' department: - _id: JoCs - _id: VlKo doi: 10.1109/ICCV.2013.288 external_id: arxiv: - '1310.1771' language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1310.1771 month: '12' oa: 1 oa_version: Preprint page: 2320 - 2327 publication_status: published publisher: IEEE publist_id: '4668' quality_controlled: '1' status: public title: Potts model, parametric maxflow and k-submodular functions type: conference user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2013' ... --- _id: '2518' abstract: - lang: eng text: A class of valued constraint satisfaction problems (VCSPs) is characterised by a valued constraint language, a fixed set of cost functions on a finite domain. An instance of the problem is specified by a sum of cost functions from the language with the goal to minimise the sum. We study which classes of finite-valued languages can be solved exactly by the basic linear programming relaxation (BLP). Thapper and Živný showed [20] that if BLP solves the language then the language admits a binary commutative fractional polymorphism. We prove that the converse is also true. This leads to a necessary and a sufficient condition which can be checked in polynomial time for a given language. In contrast, the previous necessary and sufficient condition due to [20] involved infinitely many inequalities. More recently, Thapper and Živný [21] showed (using, in particular, a technique introduced in this paper) that core languages that do not satisfy our condition are NP-hard. Taken together, these results imply that a finite-valued language can either be solved using Linear Programming or is NP-hard. alternative_title: - LNCS author: - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov citation: ama: 'Kolmogorov V. The power of linear programming for finite-valued CSPs: A constructive characterization. In: Vol 7965. Springer; 2013:625-636. doi:10.1007/978-3-642-39206-1_53' apa: 'Kolmogorov, V. (2013). The power of linear programming for finite-valued CSPs: A constructive characterization (Vol. 7965, pp. 625–636). Presented at the ICALP: Automata, Languages and Programming, Riga, Latvia: Springer. https://doi.org/10.1007/978-3-642-39206-1_53' chicago: 'Kolmogorov, Vladimir. “The Power of Linear Programming for Finite-Valued CSPs: A Constructive Characterization,” 7965:625–36. Springer, 2013. https://doi.org/10.1007/978-3-642-39206-1_53.' ieee: 'V. Kolmogorov, “The power of linear programming for finite-valued CSPs: A constructive characterization,” presented at the ICALP: Automata, Languages and Programming, Riga, Latvia, 2013, vol. 7965, no. 1, pp. 625–636.' ista: 'Kolmogorov V. 2013. The power of linear programming for finite-valued CSPs: A constructive characterization. ICALP: Automata, Languages and Programming, LNCS, vol. 7965, 625–636.' mla: 'Kolmogorov, Vladimir. The Power of Linear Programming for Finite-Valued CSPs: A Constructive Characterization. Vol. 7965, no. 1, Springer, 2013, pp. 625–36, doi:10.1007/978-3-642-39206-1_53.' short: V. Kolmogorov, in:, Springer, 2013, pp. 625–636. conference: end_date: 2013-07-12 location: Riga, Latvia name: 'ICALP: Automata, Languages and Programming' start_date: 2013-07-08 date_created: 2018-12-11T11:58:08Z date_published: 2013-07-01T00:00:00Z date_updated: 2023-02-23T10:35:42Z day: '01' department: - _id: VlKo doi: 10.1007/978-3-642-39206-1_53 external_id: arxiv: - '1207.7213' intvolume: ' 7965' issue: '1' language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1207.7213 month: '07' oa: 1 oa_version: Preprint page: 625 - 636 publication_status: published publisher: Springer publist_id: '4383' quality_controlled: '1' related_material: record: - id: '2271' relation: later_version status: public scopus_import: 1 status: public title: 'The power of linear programming for finite-valued CSPs: A constructive characterization' type: conference user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 7965 year: '2013' ... --- _id: '2828' abstract: - lang: eng text: 'We study the complexity of valued constraint satisfaction problems (VCSPs) parametrized by a constraint language, a fixed set of cost functions over a finite domain. An instance of the problem is specified by a sum of cost functions from the language and the goal is to minimize the sum. Under the unique games conjecture, the approximability of finite-valued VCSPs is well understood, see Raghavendra [2008]. However, there is no characterization of finite-valued VCSPs, let alone general-valued VCSPs, that can be solved exactly in polynomial time, thus giving insights from a combinatorial optimization perspective. We consider the case of languages containing all possible unary cost functions. In the case of languages consisting of only {0, ∞}-valued cost functions (i.e., relations), such languages have been called conservative and studied by Bulatov [2003, 2011] and recently by Barto [2011]. Since we study valued languages, we call a language conservative if it contains all finite-valued unary cost functions. The computational complexity of conservative valued languages has been studied by Cohen et al. [2006] for languages over Boolean domains, by Deineko et al. [2008] for {0, 1}-valued languages (a.k.a Max-CSP), and by Takhanov [2010a] for {0, ∞}-valued languages containing all finite-valued unary cost functions (a.k.a. Min-Cost-Hom). We prove a Schaefer-like dichotomy theorem for conservative valued languages: if all cost functions in the language satisfy a certain condition (specified by a complementary combination of STP and MJN multimor-phisms), then any instance can be solved in polynomial time (via a new algorithm developed in this article), otherwise the language is NP-hard. This is the first complete complexity classification of general-valued constraint languages over non-Boolean domains. It is a common phenomenon that complexity classifications of problems over non-Boolean domains are significantly harder than the Boolean cases. The polynomial-time algorithm we present for the tractable cases is a generalization of the submodular minimization problem and a result of Cohen et al. [2008]. Our results generalize previous results by Takhanov [2010a] and (a subset of results) by Cohen et al. [2006] and Deineko et al. [2008]. Moreover, our results do not rely on any computer-assisted search as in Deineko et al. [2008], and provide a powerful tool for proving hardness of finite-valued and general-valued languages.' article_number: '10' author: - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov - first_name: Stanislav full_name: Živný, Stanislav last_name: Živný citation: ama: Kolmogorov V, Živný S. The complexity of conservative valued CSPs. Journal of the ACM. 2013;60(2). doi:10.1145/2450142.2450146 apa: Kolmogorov, V., & Živný, S. (2013). The complexity of conservative valued CSPs. Journal of the ACM. ACM. https://doi.org/10.1145/2450142.2450146 chicago: Kolmogorov, Vladimir, and Stanislav Živný. “The Complexity of Conservative Valued CSPs.” Journal of the ACM. ACM, 2013. https://doi.org/10.1145/2450142.2450146. ieee: V. Kolmogorov and S. Živný, “The complexity of conservative valued CSPs,” Journal of the ACM, vol. 60, no. 2. ACM, 2013. ista: Kolmogorov V, Živný S. 2013. The complexity of conservative valued CSPs. Journal of the ACM. 60(2), 10. mla: Kolmogorov, Vladimir, and Stanislav Živný. “The Complexity of Conservative Valued CSPs.” Journal of the ACM, vol. 60, no. 2, 10, ACM, 2013, doi:10.1145/2450142.2450146. short: V. Kolmogorov, S. Živný, Journal of the ACM 60 (2013). date_created: 2018-12-11T11:59:48Z date_published: 2013-04-02T00:00:00Z date_updated: 2021-01-12T07:00:00Z day: '02' department: - _id: VlKo doi: 10.1145/2450142.2450146 external_id: arxiv: - '1110.2809' intvolume: ' 60' issue: '2' language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1110.2809 month: '04' oa: 1 oa_version: Preprint publication: Journal of the ACM publication_status: published publisher: ACM publist_id: '3971' quality_controlled: '1' scopus_import: 1 status: public title: The complexity of conservative valued CSPs type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 60 year: '2013' ... --- _id: '2901' abstract: - lang: eng text: ' We introduce the M-modes problem for graphical models: predicting the M label configurations of highest probability that are at the same time local maxima of the probability landscape. M-modes have multiple possible applications: because they are intrinsically diverse, they provide a principled alternative to non-maximum suppression techniques for structured prediction, they can act as codebook vectors for quantizing the configuration space, or they can form component centers for mixture model approximation. We present two algorithms for solving the M-modes problem. The first algorithm solves the problem in polynomial time when the underlying graphical model is a simple chain. The second algorithm solves the problem for junction chains. In synthetic and real dataset, we demonstrate how M-modes can improve the performance of prediction. We also use the generated modes as a tool to understand the topography of the probability distribution of configurations, for example with relation to the training set size and amount of noise in the data. ' alternative_title: - ' JMLR: W&CP' author: - first_name: Chao full_name: Chen, Chao id: 3E92416E-F248-11E8-B48F-1D18A9856A87 last_name: Chen - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov - first_name: Zhu full_name: Yan, Zhu last_name: Yan - first_name: Dimitris full_name: Metaxas, Dimitris last_name: Metaxas - first_name: Christoph full_name: Lampert, Christoph id: 40C20FD2-F248-11E8-B48F-1D18A9856A87 last_name: Lampert orcid: 0000-0001-8622-7887 citation: ama: 'Chen C, Kolmogorov V, Yan Z, Metaxas D, Lampert C. Computing the M most probable modes of a graphical model. In: Vol 31. JMLR; 2013:161-169.' apa: 'Chen, C., Kolmogorov, V., Yan, Z., Metaxas, D., & Lampert, C. (2013). Computing the M most probable modes of a graphical model (Vol. 31, pp. 161–169). Presented at the AISTATS: Conference on Uncertainty in Artificial Intelligence, Scottsdale, AZ, United States: JMLR.' chicago: Chen, Chao, Vladimir Kolmogorov, Zhu Yan, Dimitris Metaxas, and Christoph Lampert. “Computing the M Most Probable Modes of a Graphical Model,” 31:161–69. JMLR, 2013. ieee: 'C. Chen, V. Kolmogorov, Z. Yan, D. Metaxas, and C. Lampert, “Computing the M most probable modes of a graphical model,” presented at the AISTATS: Conference on Uncertainty in Artificial Intelligence, Scottsdale, AZ, United States, 2013, vol. 31, pp. 161–169.' ista: 'Chen C, Kolmogorov V, Yan Z, Metaxas D, Lampert C. 2013. Computing the M most probable modes of a graphical model. AISTATS: Conference on Uncertainty in Artificial Intelligence, JMLR: W&CP, vol. 31, 161–169.' mla: Chen, Chao, et al. Computing the M Most Probable Modes of a Graphical Model. Vol. 31, JMLR, 2013, pp. 161–69. short: C. Chen, V. Kolmogorov, Z. Yan, D. Metaxas, C. Lampert, in:, JMLR, 2013, pp. 161–169. conference: end_date: 2013-05-01 location: Scottsdale, AZ, United States name: ' AISTATS: Conference on Uncertainty in Artificial Intelligence' start_date: 2013-04-29 date_created: 2018-12-11T12:00:14Z date_published: 2013-01-01T00:00:00Z date_updated: 2021-01-12T07:00:35Z day: '01' department: - _id: HeEd - _id: VlKo - _id: ChLa intvolume: ' 31' language: - iso: eng main_file_link: - open_access: '1' url: http://jmlr.org/proceedings/papers/v31/chen13a.html month: '01' oa: 1 oa_version: None page: 161 - 169 publication_status: published publisher: JMLR publist_id: '3846' quality_controlled: '1' scopus_import: 1 status: public title: Computing the M most probable modes of a graphical model type: conference user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 31 year: '2013' ... --- _id: '2272' 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) x1...xn is the sum of terms over intervals [i,j] where each term is non-zero only if the substring xi...xj equals a prespecified pattern α. Such CRFs can be naturally applied to many sequence tagging problems.\r\nWe 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 O(nL), O(nLℓmax) and O(nLmin{|D|,log(ℓmax+1)}) where L is the combined length of input patterns, ℓmax is the maximum length of a pattern, and D is the input alphabet. This improves on the previous algorithms of (Ye et al., 2009) whose complexities are respectively O(nL|D|), O(n|Γ|L2ℓ2max) and O(nL|D|), where |Γ| is the number of input patterns.\r\nIn addition, we give an efficient algorithm for sampling. Finally, we consider the case of non-positive weights. (Komodakis & Paragios, 2009) gave an O(nL) algorithm for computing the MAP. We present a modification that has the same worst-case complexity but can beat it in the best case. " alternative_title: - JMLR article_processing_charge: No author: - first_name: Rustem full_name: Takhanov, Rustem id: 2CCAC26C-F248-11E8-B48F-1D18A9856A87 last_name: Takhanov - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov citation: ama: 'Takhanov R, Kolmogorov V. Inference algorithms for pattern-based CRFs on sequence data. In: ICML’13 Proceedings of the 30th International Conference on International. Vol 28. ML Research Press; 2013:145-153.' apa: 'Takhanov, R., & Kolmogorov, V. (2013). Inference algorithms for pattern-based CRFs on sequence data. In ICML’13 Proceedings of the 30th International Conference on International (Vol. 28, pp. 145–153). Atlanta, GA, USA: ML Research Press.' chicago: Takhanov, Rustem, and Vladimir Kolmogorov. “Inference Algorithms for Pattern-Based CRFs on Sequence Data.” In ICML’13 Proceedings of the 30th International Conference on International, 28:145–53. ML Research Press, 2013. ieee: R. Takhanov and V. Kolmogorov, “Inference algorithms for pattern-based CRFs on sequence data,” in ICML’13 Proceedings of the 30th International Conference on International, Atlanta, GA, USA, 2013, vol. 28, no. 3, pp. 145–153. ista: 'Takhanov R, Kolmogorov V. 2013. Inference algorithms for pattern-based CRFs on sequence data. ICML’13 Proceedings of the 30th International Conference on International. ICML: International Conference on Machine Learning, JMLR, vol. 28, 145–153.' mla: Takhanov, Rustem, and Vladimir Kolmogorov. “Inference Algorithms for Pattern-Based CRFs on Sequence Data.” ICML’13 Proceedings of the 30th International Conference on International, vol. 28, no. 3, ML Research Press, 2013, pp. 145–53. short: R. Takhanov, V. Kolmogorov, in:, ICML’13 Proceedings of the 30th International Conference on International, ML Research Press, 2013, pp. 145–153. conference: end_date: 2013-06-21 location: Atlanta, GA, USA name: 'ICML: International Conference on Machine Learning' start_date: 2013-06-16 date_created: 2018-12-11T11:56:41Z date_published: 2013-06-01T00:00:00Z date_updated: 2023-10-17T09:51:32Z day: '01' department: - _id: VlKo intvolume: ' 28' issue: '3' language: - iso: eng main_file_link: - open_access: '1' url: http://proceedings.mlr.press/v28/takhanov13.pdf?CFID=105472548&CFTOKEN=5c5859b5d97b4439-27B4AC58-BA92-A964-B598CAACEE6CC515 month: '06' oa: 1 oa_version: Submitted Version page: 145 - 153 publication: ICML'13 Proceedings of the 30th International Conference on International publication_status: published publisher: ML Research Press publist_id: '4672' quality_controlled: '1' related_material: record: - id: '1794' relation: later_version status: public scopus_import: '1' status: public title: Inference algorithms for pattern-based CRFs on sequence data type: conference user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 28 year: '2013' ... --- _id: '2274' abstract: - lang: eng text: "Proofs of work (PoW) have been suggested by Dwork and Naor (Crypto'92) as protection to a shared resource. The basic idea is to ask the service requestor to dedicate some non-trivial amount of computational work to every request. The original applications included prevention of spam and protection against denial of service attacks. More recently, PoWs have been used to prevent double spending in the Bitcoin digital currency system.\r\n\r\nIn this work, we put forward an alternative concept for PoWs -- so-called proofs of space (PoS), where a service requestor must dedicate a significant amount of disk space as opposed to computation. We construct secure PoS schemes in the random oracle model, using graphs with high "pebbling complexity" and Merkle hash-trees. " author: - first_name: Stefan full_name: Dziembowski, Stefan last_name: Dziembowski - first_name: Sebastian full_name: Faust, Sebastian last_name: Faust - 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 citation: ama: Dziembowski S, Faust S, Kolmogorov V, Pietrzak KZ. Proofs of Space. IST Austria; 2013. apa: Dziembowski, S., Faust, S., Kolmogorov, V., & Pietrzak, K. Z. (2013). Proofs of Space. IST Austria. chicago: Dziembowski, Stefan, Sebastian Faust, Vladimir Kolmogorov, and Krzysztof Z Pietrzak. Proofs of Space. IST Austria, 2013. ieee: S. Dziembowski, S. Faust, V. Kolmogorov, and K. Z. Pietrzak, Proofs of Space. IST Austria, 2013. ista: Dziembowski S, Faust S, Kolmogorov V, Pietrzak KZ. 2013. Proofs of Space, IST Austria,p. mla: Dziembowski, Stefan, et al. Proofs of Space. IST Austria, 2013. short: S. Dziembowski, S. Faust, V. Kolmogorov, K.Z. Pietrzak, Proofs of Space, IST Austria, 2013. date_created: 2018-12-11T11:56:42Z date_published: 2013-11-28T00:00:00Z date_updated: 2024-03-20T08:31:49Z day: '28' ddc: - '530' department: - _id: VlKo - _id: KrPi file: - access_level: open_access checksum: 37b61637b62fc079d9141c59d9f1a94f content_type: application/pdf creator: system date_created: 2018-12-12T10:16:11Z date_updated: 2020-07-14T12:45:36Z file_id: '5197' file_name: IST-2016-671-v1+1_796.pdf file_size: 405870 relation: main_file file_date_updated: 2020-07-14T12:45:36Z has_accepted_license: '1' language: - iso: eng month: '11' oa: 1 oa_version: Published Version publication_status: published publisher: IST Austria publist_id: '4670' pubrep_id: '671' related_material: record: - id: '1675' relation: later_version status: public scopus_import: 1 status: public title: Proofs of Space type: report user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2013' ... --- _id: '2930' abstract: - lang: eng text: "In this paper we investigate k-submodular functions. This natural family of discrete functions includes submodular and bisubmodular functions as the special cases k = 1 and k = 2 respectively.\r\n\r\nIn particular we generalize the known Min-Max-Theorem for submodular and bisubmodular functions. This theorem asserts that the minimum of the (bi)submodular function can be found by solving a maximization problem over a (bi)submodular polyhedron. We define a k-submodular polyhedron, prove a Min-Max-Theorem for k-submodular functions, and give a greedy algorithm to construct the vertices of the polyhedron.\r\n" acknowledgement: "We would like to thank Andrei Krokhin for encourag- ing our cooperation, for helpful discussions, and for his critical reading of the manuscript.\r\n" alternative_title: - LNCS author: - first_name: Anna full_name: Huber, Anna last_name: Huber - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov citation: ama: 'Huber A, Kolmogorov V. Towards minimizing k-submodular functions. In: Vol 7422. Springer; 2012:451-462. doi:10.1007/978-3-642-32147-4_40' apa: 'Huber, A., & Kolmogorov, V. (2012). Towards minimizing k-submodular functions (Vol. 7422, pp. 451–462). Presented at the ISCO: International Symposium on Combinatorial Optimization, Athens, Greece: Springer. https://doi.org/10.1007/978-3-642-32147-4_40' chicago: Huber, Anna, and Vladimir Kolmogorov. “Towards Minimizing K-Submodular Functions,” 7422:451–62. Springer, 2012. https://doi.org/10.1007/978-3-642-32147-4_40. ieee: 'A. Huber and V. Kolmogorov, “Towards minimizing k-submodular functions,” presented at the ISCO: International Symposium on Combinatorial Optimization, Athens, Greece, 2012, vol. 7422, pp. 451–462.' ista: 'Huber A, Kolmogorov V. 2012. Towards minimizing k-submodular functions. ISCO: International Symposium on Combinatorial Optimization, LNCS, vol. 7422, 451–462.' mla: Huber, Anna, and Vladimir Kolmogorov. Towards Minimizing K-Submodular Functions. Vol. 7422, Springer, 2012, pp. 451–62, doi:10.1007/978-3-642-32147-4_40. short: A. Huber, V. Kolmogorov, in:, Springer, 2012, pp. 451–462. conference: end_date: 2012-04-21 location: Athens, Greece name: 'ISCO: International Symposium on Combinatorial Optimization' start_date: 2012-04-19 date_created: 2018-12-11T12:00:24Z date_published: 2012-04-01T00:00:00Z date_updated: 2021-01-12T07:00:46Z day: '01' department: - _id: VlKo doi: 10.1007/978-3-642-32147-4_40 intvolume: ' 7422' language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1309.5469 month: '04' oa: 1 oa_version: Preprint page: 451 - 462 publication_status: published publisher: Springer publist_id: '3806' quality_controlled: '1' scopus_import: 1 status: public title: Towards minimizing k-submodular functions type: conference user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 7422 year: '2012' ... --- _id: '2928' abstract: - lang: eng text: ' This paper addresses the problem of approximate MAP-MRF inference in general graphical models. Following [36], we consider a family of linear programming relaxations of the problem where each relaxation is specified by a set of nested pairs of factors for which the marginalization constraint needs to be enforced. We develop a generalization of the TRW-S algorithm [9] for this problem, where we use a decomposition into junction chains, monotonic w.r.t. some ordering on the nodes. This generalizes the monotonic chains in [9] in a natural way. We also show how to deal with nested factors in an efficient way. Experiments show an improvement over min-sum diffusion, MPLP and subgradient ascent algorithms on a number of computer vision and natural language processing problems. ' article_processing_charge: No author: - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov - first_name: Thomas full_name: Schoenemann, Thomas last_name: Schoenemann citation: ama: Kolmogorov V, Schoenemann T. Generalized sequential tree-reweighted message passing. arXiv. 2012. apa: Kolmogorov, V., & Schoenemann, T. (2012). Generalized sequential tree-reweighted message passing. arXiv. ArXiv. chicago: Kolmogorov, Vladimir, and Thomas Schoenemann. “Generalized Sequential Tree-Reweighted Message Passing.” ArXiv. ArXiv, 2012. ieee: V. Kolmogorov and T. Schoenemann, “Generalized sequential tree-reweighted message passing,” arXiv. ArXiv, 2012. ista: Kolmogorov V, Schoenemann T. 2012. Generalized sequential tree-reweighted message passing. arXiv, . mla: Kolmogorov, Vladimir, and Thomas Schoenemann. “Generalized Sequential Tree-Reweighted Message Passing.” ArXiv, ArXiv, 2012. short: V. Kolmogorov, T. Schoenemann, ArXiv (2012). date_created: 2018-12-11T12:00:23Z date_published: 2012-05-29T00:00:00Z date_updated: 2021-01-12T07:00:45Z day: '29' department: - _id: VlKo external_id: arxiv: - '1205.6352' language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1205.6352 month: '05' oa: 1 oa_version: Preprint page: '16' publication: arXiv publication_status: published publisher: ArXiv publist_id: '3809' status: public title: Generalized sequential tree-reweighted message passing type: preprint user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2012' ...