--- _id: '68' abstract: - lang: eng text: The most common assumption made in statistical learning theory is the assumption of the independent and identically distributed (i.i.d.) data. While being very convenient mathematically, it is often very clearly violated in practice. This disparity between the machine learning theory and applications underlies a growing demand in the development of algorithms that learn from dependent data and theory that can provide generalization guarantees similar to the independent situations. This thesis is dedicated to two variants of dependencies that can arise in practice. One is a dependence on the level of samples in a single learning task. Another dependency type arises in the multi-task setting when the tasks are dependent on each other even though the data for them can be i.i.d. In both cases we model the data (samples or tasks) as stochastic processes and introduce new algorithms for both settings that take into account and exploit the resulting dependencies. We prove the theoretical guarantees on the performance of the introduced algorithms under different evaluation criteria and, in addition, we compliment the theoretical study by the empirical one, where we evaluate some of the algorithms on two real world datasets to highlight their practical applicability. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Alexander full_name: Zimin, Alexander id: 37099E9C-F248-11E8-B48F-1D18A9856A87 last_name: Zimin citation: ama: Zimin A. Learning from dependent data. 2018. doi:10.15479/AT:ISTA:TH1048 apa: Zimin, A. (2018). Learning from dependent data. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:TH1048 chicago: Zimin, Alexander. “Learning from Dependent Data.” Institute of Science and Technology Austria, 2018. https://doi.org/10.15479/AT:ISTA:TH1048. ieee: A. Zimin, “Learning from dependent data,” Institute of Science and Technology Austria, 2018. ista: Zimin A. 2018. Learning from dependent data. Institute of Science and Technology Austria. mla: Zimin, Alexander. Learning from Dependent Data. Institute of Science and Technology Austria, 2018, doi:10.15479/AT:ISTA:TH1048. short: A. Zimin, Learning from Dependent Data, Institute of Science and Technology Austria, 2018. date_created: 2018-12-11T11:44:27Z date_published: 2018-09-01T00:00:00Z date_updated: 2023-09-07T12:29:07Z day: '01' ddc: - '004' - '519' degree_awarded: PhD department: - _id: ChLa doi: 10.15479/AT:ISTA:TH1048 ec_funded: 1 file: - access_level: open_access checksum: e849dd40a915e4d6c5572b51b517f098 content_type: application/pdf creator: dernst date_created: 2019-04-09T07:32:47Z date_updated: 2020-07-14T12:47:40Z file_id: '6253' file_name: 2018_Thesis_Zimin.pdf file_size: 1036137 relation: main_file - access_level: closed checksum: da092153cec55c97461bd53c45c5d139 content_type: application/zip creator: dernst date_created: 2019-04-09T07:32:47Z date_updated: 2020-07-14T12:47:40Z file_id: '6254' file_name: 2018_Thesis_Zimin_Source.zip file_size: 637490 relation: source_file file_date_updated: 2020-07-14T12:47:40Z has_accepted_license: '1' language: - iso: eng month: '09' oa: 1 oa_version: Published Version page: '92' project: - _id: 2532554C-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '308036' name: Lifelong Learning of Visual Scene Understanding publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '7986' pubrep_id: '1048' status: public supervisor: - first_name: Christoph full_name: Lampert, Christoph id: 40C20FD2-F248-11E8-B48F-1D18A9856A87 last_name: Lampert orcid: 0000-0001-8622-7887 title: Learning from dependent data type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2018' ... --- _id: '83' abstract: - lang: eng text: "A proof system is a protocol between a prover and a verifier over a common input in which an honest prover convinces the verifier of the validity of true statements. Motivated by the success of decentralized cryptocurrencies, exemplified by Bitcoin, the focus of this thesis will be on proof systems which found applications in some sustainable alternatives to Bitcoin, such as the Spacemint and Chia cryptocurrencies. In particular, we focus on proofs of space and proofs of sequential work.\r\nProofs of space (PoSpace) were suggested as more ecological, economical, and egalitarian alternative to the energy-wasteful proof-of-work mining of Bitcoin. However, the state-of-the-art constructions of PoSpace are based on sophisticated graph pebbling lower bounds, and are therefore complex. Moreover, when these PoSpace are used in cryptocurrencies like Spacemint, miners can only start mining after ensuring that a commitment to their space is already added in a special transaction to the blockchain. Proofs of sequential work (PoSW) are proof systems in which a prover, upon receiving a statement x and a time parameter T, computes a proof which convinces the verifier that T time units had passed since x was received. Whereas Spacemint assumes synchrony to retain some interesting Bitcoin dynamics, Chia requires PoSW with unique proofs, i.e., PoSW in which it is hard to come up with more than one accepting proof for any true statement. In this thesis we construct simple and practically-efficient PoSpace and PoSW. When using our PoSpace in cryptocurrencies, miners can start mining on the fly, like in Bitcoin, and unlike current constructions of PoSW, which either achieve efficient verification of sequential work, or faster-than-recomputing verification of correctness of proofs, but not both at the same time, ours achieve the best of these two worlds." alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Hamza M full_name: Abusalah, Hamza M id: 40297222-F248-11E8-B48F-1D18A9856A87 last_name: Abusalah citation: ama: Abusalah HM. Proof systems for sustainable decentralized cryptocurrencies. 2018. doi:10.15479/AT:ISTA:TH_1046 apa: Abusalah, H. M. (2018). Proof systems for sustainable decentralized cryptocurrencies. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:TH_1046 chicago: Abusalah, Hamza M. “Proof Systems for Sustainable Decentralized Cryptocurrencies.” Institute of Science and Technology Austria, 2018. https://doi.org/10.15479/AT:ISTA:TH_1046. ieee: H. M. Abusalah, “Proof systems for sustainable decentralized cryptocurrencies,” Institute of Science and Technology Austria, 2018. ista: Abusalah HM. 2018. Proof systems for sustainable decentralized cryptocurrencies. Institute of Science and Technology Austria. mla: Abusalah, Hamza M. Proof Systems for Sustainable Decentralized Cryptocurrencies. Institute of Science and Technology Austria, 2018, doi:10.15479/AT:ISTA:TH_1046. short: H.M. Abusalah, Proof Systems for Sustainable Decentralized Cryptocurrencies, Institute of Science and Technology Austria, 2018. date_created: 2018-12-11T11:44:32Z date_published: 2018-09-05T00:00:00Z date_updated: 2023-09-07T12:30:23Z day: '05' ddc: - '004' degree_awarded: PhD department: - _id: KrPi doi: 10.15479/AT:ISTA:TH_1046 ec_funded: 1 file: - access_level: open_access checksum: c4b5f7d111755d1396787f41886fc674 content_type: application/pdf creator: dernst date_created: 2019-04-09T06:43:41Z date_updated: 2020-07-14T12:48:11Z file_id: '6245' file_name: 2018_Thesis_Abusalah.pdf file_size: 876241 relation: main_file - access_level: closed checksum: 0f382ac56b471c48fd907d63eb87dafe content_type: application/x-gzip creator: dernst date_created: 2019-04-09T06:43:41Z date_updated: 2020-07-14T12:48:11Z file_id: '6246' file_name: 2018_Thesis_Abusalah_source.tar.gz file_size: 2029190 relation: source_file file_date_updated: 2020-07-14T12:48:11Z has_accepted_license: '1' language: - iso: eng month: '09' oa: 1 oa_version: Published Version page: '59' project: - _id: 258C570E-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '259668' name: Provable Security for Physical Cryptography - _id: 258AA5B2-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '682815' name: Teaching Old Crypto New Tricks publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '7971' pubrep_id: '1046' related_material: record: - id: '1229' relation: part_of_dissertation status: public - id: '1235' relation: part_of_dissertation status: public - id: '1236' relation: part_of_dissertation status: public - id: '559' relation: part_of_dissertation status: public status: public supervisor: - first_name: Krzysztof Z full_name: Pietrzak, Krzysztof Z id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87 last_name: Pietrzak orcid: 0000-0002-9139-1654 title: Proof systems for sustainable decentralized cryptocurrencies type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2018' ... --- _id: '197' abstract: - lang: eng text: Modern computer vision systems heavily rely on statistical machine learning models, which typically require large amounts of labeled data to be learned reliably. Moreover, very recently computer vision research widely adopted techniques for representation learning, which further increase the demand for labeled data. However, for many important practical problems there is relatively small amount of labeled data available, so it is problematic to leverage full potential of the representation learning methods. One way to overcome this obstacle is to invest substantial resources into producing large labelled datasets. Unfortunately, this can be prohibitively expensive in practice. In this thesis we focus on the alternative way of tackling the aforementioned issue. We concentrate on methods, which make use of weakly-labeled or even unlabeled data. Specifically, the first half of the thesis is dedicated to the semantic image segmentation task. We develop a technique, which achieves competitive segmentation performance and only requires annotations in a form of global image-level labels instead of dense segmentation masks. Subsequently, we present a new methodology, which further improves segmentation performance by leveraging tiny additional feedback from a human annotator. By using our methods practitioners can greatly reduce the amount of data annotation effort, which is required to learn modern image segmentation models. In the second half of the thesis we focus on methods for learning from unlabeled visual data. We study a family of autoregressive models for modeling structure of natural images and discuss potential applications of these models. Moreover, we conduct in-depth study of one of these applications, where we develop the state-of-the-art model for the probabilistic image colorization task. acknowledgement: I also gratefully acknowledge the support of NVIDIA Corporation with the donation of the GPUs used for this research. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Alexander full_name: Kolesnikov, Alexander id: 2D157DB6-F248-11E8-B48F-1D18A9856A87 last_name: Kolesnikov citation: ama: Kolesnikov A. Weakly-Supervised Segmentation and Unsupervised Modeling of Natural Images. 2018. doi:10.15479/AT:ISTA:th_1021 apa: Kolesnikov, A. (2018). Weakly-Supervised Segmentation and Unsupervised Modeling of Natural Images. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_1021 chicago: Kolesnikov, Alexander. “Weakly-Supervised Segmentation and Unsupervised Modeling of Natural Images.” Institute of Science and Technology Austria, 2018. https://doi.org/10.15479/AT:ISTA:th_1021. ieee: A. Kolesnikov, “Weakly-Supervised Segmentation and Unsupervised Modeling of Natural Images,” Institute of Science and Technology Austria, 2018. ista: Kolesnikov A. 2018. Weakly-Supervised Segmentation and Unsupervised Modeling of Natural Images. Institute of Science and Technology Austria. mla: Kolesnikov, Alexander. Weakly-Supervised Segmentation and Unsupervised Modeling of Natural Images. Institute of Science and Technology Austria, 2018, doi:10.15479/AT:ISTA:th_1021. short: A. Kolesnikov, Weakly-Supervised Segmentation and Unsupervised Modeling of Natural Images, Institute of Science and Technology Austria, 2018. date_created: 2018-12-11T11:45:09Z date_published: 2018-05-25T00:00:00Z date_updated: 2023-09-07T12:51:46Z day: '25' ddc: - '004' degree_awarded: PhD department: - _id: ChLa doi: 10.15479/AT:ISTA:th_1021 ec_funded: 1 file: - access_level: open_access checksum: bc678e02468d8ebc39dc7267dfb0a1c4 content_type: application/pdf creator: system date_created: 2018-12-12T10:14:57Z date_updated: 2020-07-14T12:45:22Z file_id: '5113' file_name: IST-2018-1021-v1+1_thesis-unsigned-pdfa.pdf file_size: 12918758 relation: main_file - access_level: closed checksum: bc66973b086da5a043f1162dcfb1fde4 content_type: application/zip creator: dernst date_created: 2019-04-05T09:34:49Z date_updated: 2020-07-14T12:45:22Z file_id: '6225' file_name: 2018_Thesis_Kolesnikov_source.zip file_size: 55973760 relation: source_file file_date_updated: 2020-07-14T12:45:22Z has_accepted_license: '1' language: - iso: eng month: '05' oa: 1 oa_version: Published Version page: '113' project: - _id: 2532554C-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '308036' name: Lifelong Learning of Visual Scene Understanding publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '7718' pubrep_id: '1021' status: public supervisor: - first_name: Christoph full_name: Lampert, Christoph id: 40C20FD2-F248-11E8-B48F-1D18A9856A87 last_name: Lampert orcid: 0000-0001-8622-7887 title: Weakly-Supervised Segmentation and Unsupervised Modeling of Natural Images type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2018' ... --- _id: '6774' abstract: - lang: eng text: "A central problem of algebraic topology is to understand the homotopy groups \ \U0001D70B\U0001D451(\U0001D44B) of a topological space X. For the computational version of the problem, it is well known that there is no algorithm to decide whether the fundamental group \U0001D70B1(\U0001D44B) of a given finite simplicial complex X is trivial. On the other hand, there are several algorithms that, given a finite simplicial complex X that is simply connected (i.e., with \U0001D70B1(\U0001D44B) \ trivial), compute the higher homotopy group \U0001D70B\U0001D451(\U0001D44B) \ for any given \U0001D451≥2 . However, these algorithms come with a caveat: They compute the isomorphism type of \U0001D70B\U0001D451(\U0001D44B) , \U0001D451≥2 \ as an abstract finitely generated abelian group given by generators and relations, but they work with very implicit representations of the elements of \U0001D70B\U0001D451(\U0001D44B) . Converting elements of this abstract group into explicit geometric maps from the d-dimensional sphere \U0001D446\U0001D451 to X has been one of the main unsolved problems in the emerging field of computational homotopy theory. Here we present an algorithm that, given a simply connected space X, computes \U0001D70B\U0001D451(\U0001D44B) \ and represents its elements as simplicial maps from a suitable triangulation of the d-sphere \U0001D446\U0001D451 to X. For fixed d, the algorithm runs in time exponential in size(\U0001D44B) , the number of simplices of X. Moreover, we prove that this is optimal: For every fixed \U0001D451≥2 , we construct a family of simply connected spaces X such that for any simplicial map representing a generator of \U0001D70B\U0001D451(\U0001D44B) , the size of the triangulation of \U0001D446\U0001D451 on which the map is defined, is exponential in size(\U0001D44B) ." article_type: original author: - first_name: Marek full_name: Filakovský, Marek id: 3E8AF77E-F248-11E8-B48F-1D18A9856A87 last_name: Filakovský - first_name: Peter full_name: Franek, Peter id: 473294AE-F248-11E8-B48F-1D18A9856A87 last_name: Franek orcid: 0000-0001-8878-8397 - first_name: Uli full_name: Wagner, Uli id: 36690CA2-F248-11E8-B48F-1D18A9856A87 last_name: Wagner orcid: 0000-0002-1494-0568 - first_name: Stephan Y full_name: Zhechev, Stephan Y id: 3AA52972-F248-11E8-B48F-1D18A9856A87 last_name: Zhechev citation: ama: Filakovský M, Franek P, Wagner U, Zhechev SY. Computing simplicial representatives of homotopy group elements. Journal of Applied and Computational Topology. 2018;2(3-4):177-231. doi:10.1007/s41468-018-0021-5 apa: Filakovský, M., Franek, P., Wagner, U., & Zhechev, S. Y. (2018). Computing simplicial representatives of homotopy group elements. Journal of Applied and Computational Topology. Springer. https://doi.org/10.1007/s41468-018-0021-5 chicago: Filakovský, Marek, Peter Franek, Uli Wagner, and Stephan Y Zhechev. “Computing Simplicial Representatives of Homotopy Group Elements.” Journal of Applied and Computational Topology. Springer, 2018. https://doi.org/10.1007/s41468-018-0021-5. ieee: M. Filakovský, P. Franek, U. Wagner, and S. Y. Zhechev, “Computing simplicial representatives of homotopy group elements,” Journal of Applied and Computational Topology, vol. 2, no. 3–4. Springer, pp. 177–231, 2018. ista: Filakovský M, Franek P, Wagner U, Zhechev SY. 2018. Computing simplicial representatives of homotopy group elements. Journal of Applied and Computational Topology. 2(3–4), 177–231. mla: Filakovský, Marek, et al. “Computing Simplicial Representatives of Homotopy Group Elements.” Journal of Applied and Computational Topology, vol. 2, no. 3–4, Springer, 2018, pp. 177–231, doi:10.1007/s41468-018-0021-5. short: M. Filakovský, P. Franek, U. Wagner, S.Y. Zhechev, Journal of Applied and Computational Topology 2 (2018) 177–231. date_created: 2019-08-08T06:47:40Z date_published: 2018-12-01T00:00:00Z date_updated: 2023-09-07T13:10:36Z day: '01' ddc: - '514' department: - _id: UlWa doi: 10.1007/s41468-018-0021-5 file: - access_level: open_access checksum: cf9e7fcd2a113dd4828774fc75cdb7e8 content_type: application/pdf creator: dernst date_created: 2019-08-08T06:55:21Z date_updated: 2020-07-14T12:47:40Z file_id: '6775' file_name: 2018_JourAppliedComputTopology_Filakovsky.pdf file_size: 1056278 relation: main_file file_date_updated: 2020-07-14T12:47:40Z has_accepted_license: '1' intvolume: ' 2' issue: 3-4 language: - iso: eng license: https://creativecommons.org/licenses/by/4.0/ month: '12' oa: 1 oa_version: Published Version page: 177-231 project: - _id: 25F8B9BC-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: M01980 name: Robust invariants of Nonlinear Systems - _id: 3AC91DDA-15DF-11EA-824D-93A3E7B544D1 call_identifier: FWF name: FWF Open Access Fund publication: Journal of Applied and Computational Topology publication_identifier: eissn: - 2367-1734 issn: - 2367-1726 publication_status: published publisher: Springer quality_controlled: '1' related_material: record: - id: '6681' relation: dissertation_contains status: public status: public title: Computing simplicial representatives of homotopy group elements tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 2 year: '2018' ... --- _id: '133' abstract: - lang: eng text: Synchronous programs are easy to specify because the side effects of an operation are finished by the time the invocation of the operation returns to the caller. Asynchronous programs, on the other hand, are difficult to specify because there are side effects due to pending computation scheduled as a result of the invocation of an operation. They are also difficult to verify because of the large number of possible interleavings of concurrent computation threads. We present synchronization, a new proof rule that simplifies the verification of asynchronous programs by introducing the fiction, for proof purposes, that asynchronous operations complete synchronously. Synchronization summarizes an asynchronous computation as immediate atomic effect. Modular verification is enabled via pending asynchronous calls in atomic summaries, and a complementary proof rule that eliminates pending asynchronous calls when components and their specifications are composed. We evaluate synchronization in the context of a multi-layer refinement verification methodology on a collection of benchmark programs. alternative_title: - LIPIcs article_number: '21' author: - first_name: Bernhard full_name: Kragl, Bernhard id: 320FC952-F248-11E8-B48F-1D18A9856A87 last_name: Kragl orcid: 0000-0001-7745-9117 - first_name: Shaz full_name: Qadeer, Shaz last_name: Qadeer - first_name: Thomas A full_name: Henzinger, Thomas A id: 40876CD8-F248-11E8-B48F-1D18A9856A87 last_name: Henzinger orcid: 0000−0002−2985−7724 citation: ama: 'Kragl B, Qadeer S, Henzinger TA. Synchronizing the asynchronous. In: Vol 118. Schloss Dagstuhl - Leibniz-Zentrum für Informatik; 2018. doi:10.4230/LIPIcs.CONCUR.2018.21' apa: 'Kragl, B., Qadeer, S., & Henzinger, T. A. (2018). Synchronizing the asynchronous (Vol. 118). Presented at the CONCUR: International Conference on Concurrency Theory, Beijing, China: Schloss Dagstuhl - Leibniz-Zentrum für Informatik. https://doi.org/10.4230/LIPIcs.CONCUR.2018.21' chicago: Kragl, Bernhard, Shaz Qadeer, and Thomas A Henzinger. “Synchronizing the Asynchronous,” Vol. 118. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2018. https://doi.org/10.4230/LIPIcs.CONCUR.2018.21. ieee: 'B. Kragl, S. Qadeer, and T. A. Henzinger, “Synchronizing the asynchronous,” presented at the CONCUR: International Conference on Concurrency Theory, Beijing, China, 2018, vol. 118.' ista: 'Kragl B, Qadeer S, Henzinger TA. 2018. Synchronizing the asynchronous. CONCUR: International Conference on Concurrency Theory, LIPIcs, vol. 118, 21.' mla: Kragl, Bernhard, et al. Synchronizing the Asynchronous. Vol. 118, 21, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2018, doi:10.4230/LIPIcs.CONCUR.2018.21. short: B. Kragl, S. Qadeer, T.A. Henzinger, in:, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2018. conference: end_date: 2018-09-07 location: Beijing, China name: 'CONCUR: International Conference on Concurrency Theory' start_date: 2018-09-04 date_created: 2018-12-11T11:44:48Z date_published: 2018-08-13T00:00:00Z date_updated: 2023-09-07T13:18:00Z day: '13' ddc: - '000' department: - _id: ToHe doi: 10.4230/LIPIcs.CONCUR.2018.21 file: - access_level: open_access checksum: c90895f4c5fafc18ddc54d1c8848077e content_type: application/pdf creator: system date_created: 2018-12-12T10:18:46Z date_updated: 2020-07-14T12:44:44Z file_id: '5368' file_name: IST-2018-853-v2+2_concur2018.pdf file_size: 745438 relation: main_file file_date_updated: 2020-07-14T12:44:44Z has_accepted_license: '1' intvolume: ' 118' language: - iso: eng month: '08' oa: 1 oa_version: Published Version project: - _id: 25F2ACDE-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: S11402-N23 name: Rigorous Systems Engineering - _id: 25F5A88A-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: S11402-N23 name: Moderne Concurrency Paradigms publication_identifier: issn: - '18688969' publication_status: published publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik publist_id: '7790' pubrep_id: '1039' quality_controlled: '1' related_material: record: - id: '6426' relation: earlier_version status: public - id: '8332' relation: dissertation_contains status: public scopus_import: 1 status: public title: Synchronizing the asynchronous tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: conference user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 118 year: '2018' ...