[{"oa":1,"publisher":"ACM","quality_controlled":"1","date_created":"2019-08-09T09:54:20Z","date_published":"2019-10-01T00:00:00Z","doi":"10.1145/3360555","publication":"Proceedings of the 34th ACM International Conference on Object-Oriented Programming, Systems, Languages, and Applications ","day":"01","year":"2019","has_accepted_license":"1","project":[{"_id":"25892FC0-B435-11E9-9278-68D0E5697425","name":"Efficient Algorithms for Computer Aided Verification","grant_number":"ICT15-003"},{"name":"Game Theory","grant_number":"S11407","_id":"25863FF4-B435-11E9-9278-68D0E5697425","call_identifier":"FWF"},{"name":"Quantitative Graph Games: Theory and Applications","grant_number":"279307","call_identifier":"FP7","_id":"2581B60A-B435-11E9-9278-68D0E5697425"},{"name":"Quantitative Analysis of Probablistic Systems with a focus on Crypto-currencies","_id":"267066CE-B435-11E9-9278-68D0E5697425"},{"name":"Quantitative Game-theoretic Analysis of Blockchain Applications and Smart Contracts","_id":"266EEEC0-B435-11E9-9278-68D0E5697425"}],"article_number":"129","title":"Modular verification for almost-sure termination of probabilistic programs","external_id":{"arxiv":["1901.06087"]},"article_processing_charge":"No","author":[{"last_name":"Huang","full_name":"Huang, Mingzhang","first_name":"Mingzhang"},{"first_name":"Hongfei","last_name":"Fu","full_name":"Fu, Hongfei"},{"orcid":"0000-0002-4561-241X","full_name":"Chatterjee, Krishnendu","last_name":"Chatterjee","first_name":"Krishnendu","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Goharshady","full_name":"Goharshady, Amir Kafshdar","orcid":"0000-0003-1702-6584","first_name":"Amir Kafshdar","id":"391365CE-F248-11E8-B48F-1D18A9856A87"}],"user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","citation":{"ama":"Huang M, Fu H, Chatterjee K, Goharshady AK. Modular verification for almost-sure termination of probabilistic programs. In: Proceedings of the 34th ACM International Conference on Object-Oriented Programming, Systems, Languages, and Applications . Vol 3. ACM; 2019. doi:10.1145/3360555","apa":"Huang, M., Fu, H., Chatterjee, K., & Goharshady, A. K. (2019). Modular verification for almost-sure termination of probabilistic programs. In Proceedings of the 34th ACM International Conference on Object-Oriented Programming, Systems, Languages, and Applications (Vol. 3). Athens, Greece: ACM. https://doi.org/10.1145/3360555","ieee":"M. Huang, H. Fu, K. Chatterjee, and A. K. Goharshady, “Modular verification for almost-sure termination of probabilistic programs,” in Proceedings of the 34th ACM International Conference on Object-Oriented Programming, Systems, Languages, and Applications , Athens, Greece, 2019, vol. 3.","short":"M. Huang, H. Fu, K. Chatterjee, A.K. Goharshady, in:, Proceedings of the 34th ACM International Conference on Object-Oriented Programming, Systems, Languages, and Applications , ACM, 2019.","mla":"Huang, Mingzhang, et al. “Modular Verification for Almost-Sure Termination of Probabilistic Programs.” Proceedings of the 34th ACM International Conference on Object-Oriented Programming, Systems, Languages, and Applications , vol. 3, 129, ACM, 2019, doi:10.1145/3360555.","ista":"Huang M, Fu H, Chatterjee K, Goharshady AK. 2019. Modular verification for almost-sure termination of probabilistic programs. Proceedings of the 34th ACM International Conference on Object-Oriented Programming, Systems, Languages, and Applications . OOPSLA: Object-oriented Programming, Systems, Languages and Applications vol. 3, 129.","chicago":"Huang, Mingzhang, Hongfei Fu, Krishnendu Chatterjee, and Amir Kafshdar Goharshady. “Modular Verification for Almost-Sure Termination of Probabilistic Programs.” In Proceedings of the 34th ACM International Conference on Object-Oriented Programming, Systems, Languages, and Applications , Vol. 3. ACM, 2019. https://doi.org/10.1145/3360555."},"intvolume":" 3","month":"10","oa_version":"Published Version","abstract":[{"text":"In this work, we consider the almost-sure termination problem for probabilistic programs that asks whether a\r\ngiven probabilistic program terminates with probability 1. Scalable approaches for program analysis often\r\nrely on modularity as their theoretical basis. In non-probabilistic programs, the classical variant rule (V-rule)\r\nof Floyd-Hoare logic provides the foundation for modular analysis. Extension of this rule to almost-sure\r\ntermination of probabilistic programs is quite tricky, and a probabilistic variant was proposed in [16]. While the\r\nproposed probabilistic variant cautiously addresses the key issue of integrability, we show that the proposed\r\nmodular rule is still not sound for almost-sure termination of probabilistic programs.\r\nBesides establishing unsoundness of the previous rule, our contributions are as follows: First, we present a\r\nsound modular rule for almost-sure termination of probabilistic programs. Our approach is based on a novel\r\nnotion of descent supermartingales. Second, for algorithmic approaches, we consider descent supermartingales\r\nthat are linear and show that they can be synthesized in polynomial time. Finally, we present experimental\r\nresults on a variety of benchmarks and several natural examples that model various types of nested while\r\nloops in probabilistic programs and demonstrate that our approach is able to efficiently prove their almost-sure\r\ntermination property","lang":"eng"}],"license":"https://creativecommons.org/licenses/by-nc/4.0/","ec_funded":1,"volume":3,"related_material":{"record":[{"status":"public","id":"8934","relation":"dissertation_contains"}]},"language":[{"iso":"eng"}],"file":[{"relation":"main_file","access_level":"open_access","content_type":"application/pdf","checksum":"3482d8ace6fb4991eb7810e3b70f1b9f","file_id":"6807","creator":"akafshda","file_size":1024643,"date_updated":"2020-07-14T12:47:40Z","file_name":"oopsla-2019.pdf","date_created":"2019-08-12T15:40:57Z"},{"creator":"dernst","file_size":538579,"date_updated":"2020-07-14T12:47:40Z","file_name":"2019_ACM_Huang.pdf","date_created":"2020-05-12T15:15:14Z","relation":"main_file","access_level":"open_access","content_type":"application/pdf","checksum":"4e5a6fb2b59a75222a4e8335a5a60eac","file_id":"7821"}],"publication_status":"published","status":"public","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by-nc/4.0/legalcode","image":"/images/cc_by_nc.png","name":"Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)","short":"CC BY-NC (4.0)"},"conference":{"start_date":"2019-10-23","location":"Athens, Greece","end_date":"2019-10-25","name":"OOPSLA: Object-oriented Programming, Systems, Languages and Applications"},"type":"conference","_id":"6780","file_date_updated":"2020-07-14T12:47:40Z","department":[{"_id":"KrCh"}],"ddc":["000"],"date_updated":"2024-03-27T23:30:33Z"},{"department":[{"_id":"KrCh"}],"file_date_updated":"2020-07-14T12:47:29Z","ddc":["004"],"date_updated":"2024-03-27T23:30:33Z","pubrep_id":"1056","status":"public","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"type":"journal_article","_id":"6380","ec_funded":1,"license":"https://creativecommons.org/licenses/by/4.0/","related_material":{"record":[{"status":"public","id":"8934","relation":"dissertation_contains"}]},"volume":3,"issue":"POPL","language":[{"iso":"eng"}],"file":[{"creator":"dernst","file_size":1294962,"date_updated":"2020-07-14T12:47:29Z","file_name":"2019_ACM_POPL_Chatterjee.pdf","date_created":"2019-05-06T12:23:11Z","relation":"main_file","access_level":"open_access","content_type":"application/pdf","file_id":"6381","checksum":"c157752f96877b36685ad7063ada4524"}],"publication_status":"published","publication_identifier":{"issn":["2475-1421"]},"intvolume":" 3","month":"01","oa_version":"Published Version","abstract":[{"lang":"eng","text":"There is a huge gap between the speeds of modern caches and main memories, and therefore cache misses account for a considerable loss of efficiency in programs. The predominant technique to address this issue has been Data Packing: data elements that are frequently accessed within time proximity are packed into the same cache block, thereby minimizing accesses to the main memory. We consider the algorithmic problem of Data Packing on a two-level memory system. Given a reference sequence R of accesses to data elements, the task is to partition the elements into cache blocks such that the number of cache misses on R is minimized. The problem is notoriously difficult: it is NP-hard even when the cache has size 1, and is hard to approximate for any cache size larger than 4. Therefore, all existing techniques for Data Packing are based on heuristics and lack theoretical guarantees. In this work, we present the first positive theoretical results for Data Packing, along with new and stronger negative results. We consider the problem under the lens of the underlying access hypergraphs, which are hypergraphs of affinities between the data elements, where the order of an access hypergraph corresponds to the size of the affinity group. We study the problem parameterized by the treewidth of access hypergraphs, which is a standard notion in graph theory to measure the closeness of a graph to a tree. Our main results are as follows: We show there is a number q* depending on the cache parameters such that (a) if the access hypergraph of order q* has constant treewidth, then there is a linear-time algorithm for Data Packing; (b)the Data Packing problem remains NP-hard even if the access hypergraph of order q*-1 has constant treewidth. Thus, we establish a fine-grained dichotomy depending on a single parameter, namely, the highest order among access hypegraphs that have constant treewidth; and establish the optimal value q* of this parameter. Finally, we present an experimental evaluation of a prototype implementation of our algorithm. Our results demonstrate that, in practice, access hypergraphs of many commonly-used algorithms have small treewidth. We compare our approach with several state-of-the-art heuristic-based algorithms and show that our algorithm leads to significantly fewer cache-misses. "}],"title":"Efficient parameterized algorithms for data packing","author":[{"orcid":"0000-0002-4561-241X","full_name":"Chatterjee, Krishnendu","last_name":"Chatterjee","first_name":"Krishnendu","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Amir Kafshdar","id":"391365CE-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0003-1702-6584","full_name":"Goharshady, Amir Kafshdar","last_name":"Goharshady"},{"last_name":"Okati","full_name":"Okati, Nastaran","first_name":"Nastaran"},{"orcid":"0000-0002-8943-0722","full_name":"Pavlogiannis, Andreas","last_name":"Pavlogiannis","id":"49704004-F248-11E8-B48F-1D18A9856A87","first_name":"Andreas"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"ista":"Chatterjee K, Goharshady AK, Okati N, Pavlogiannis A. 2019. Efficient parameterized algorithms for data packing. Proceedings of the ACM on Programming Languages. 3(POPL), 53.","chicago":"Chatterjee, Krishnendu, Amir Kafshdar Goharshady, Nastaran Okati, and Andreas Pavlogiannis. “Efficient Parameterized Algorithms for Data Packing.” Proceedings of the ACM on Programming Languages. ACM, 2019. https://doi.org/10.1145/3290366.","apa":"Chatterjee, K., Goharshady, A. K., Okati, N., & Pavlogiannis, A. (2019). Efficient parameterized algorithms for data packing. Proceedings of the ACM on Programming Languages. ACM. https://doi.org/10.1145/3290366","ama":"Chatterjee K, Goharshady AK, Okati N, Pavlogiannis A. Efficient parameterized algorithms for data packing. Proceedings of the ACM on Programming Languages. 2019;3(POPL). doi:10.1145/3290366","ieee":"K. Chatterjee, A. K. Goharshady, N. Okati, and A. Pavlogiannis, “Efficient parameterized algorithms for data packing,” Proceedings of the ACM on Programming Languages, vol. 3, no. POPL. ACM, 2019.","short":"K. Chatterjee, A.K. Goharshady, N. Okati, A. Pavlogiannis, Proceedings of the ACM on Programming Languages 3 (2019).","mla":"Chatterjee, Krishnendu, et al. “Efficient Parameterized Algorithms for Data Packing.” Proceedings of the ACM on Programming Languages, vol. 3, no. POPL, 53, ACM, 2019, doi:10.1145/3290366."},"project":[{"_id":"25892FC0-B435-11E9-9278-68D0E5697425","name":"Efficient Algorithms for Computer Aided Verification","grant_number":"ICT15-003"},{"grant_number":"S 11407_N23","name":"Rigorous Systems Engineering","_id":"25832EC2-B435-11E9-9278-68D0E5697425","call_identifier":"FWF"},{"grant_number":"279307","name":"Quantitative Graph Games: Theory and Applications","call_identifier":"FP7","_id":"2581B60A-B435-11E9-9278-68D0E5697425"}],"article_number":"53","date_created":"2019-05-06T12:18:17Z","date_published":"2019-01-01T00:00:00Z","doi":"10.1145/3290366","publication":"Proceedings of the ACM on Programming Languages","day":"01","year":"2019","has_accepted_license":"1","oa":1,"quality_controlled":"1","publisher":"ACM"},{"date_updated":"2024-03-27T23:30:33Z","department":[{"_id":"KrCh"}],"_id":"6056","status":"public","conference":{"name":"IEEE International Conference on Blockchain and Cryptocurrency","location":"Seoul, Korea","end_date":"2019-05-17","start_date":"2019-05-14"},"type":"conference","language":[{"iso":"eng"}],"publication_status":"published","ec_funded":1,"related_material":{"record":[{"relation":"dissertation_contains","id":"8934","status":"public"}]},"oa_version":"Preprint","abstract":[{"lang":"eng","text":"In today's programmable blockchains, smart contracts are limited to being deterministic and non-probabilistic. This lack of randomness is a consequential limitation, given that a wide variety of real-world financial contracts, such as casino games and lotteries, depend entirely on randomness. As a result, several ad-hoc random number generation approaches have been developed to be used in smart contracts. These include ideas such as using an oracle or relying on the block hash. However, these approaches are manipulatable, i.e. their output can be tampered with by parties who might not be neutral, such as the owner of the oracle or the miners.We propose a novel game-theoretic approach for generating provably unmanipulatable pseudorandom numbers on the blockchain. Our approach allows smart contracts to access a trustworthy source of randomness that does not rely on potentially compromised miners or oracles, hence enabling the creation of a new generation of smart contracts that are not limited to being non-probabilistic and can be drawn from the much more general class of probabilistic programs."}],"month":"05","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1902.07986"}],"scopus_import":1,"user_id":"3E5EF7F0-F248-11E8-B48F-1D18A9856A87","citation":{"ista":"Chatterjee K, Goharshady AK, Pourdamghani A. 2019. Probabilistic smart contracts: Secure randomness on the blockchain. IEEE International Conference on Blockchain and Cryptocurrency. IEEE International Conference on Blockchain and Cryptocurrency, 8751326.","chicago":"Chatterjee, Krishnendu, Amir Kafshdar Goharshady, and Arash Pourdamghani. “Probabilistic Smart Contracts: Secure Randomness on the Blockchain.” In IEEE International Conference on Blockchain and Cryptocurrency. IEEE, 2019. https://doi.org/10.1109/BLOC.2019.8751326.","apa":"Chatterjee, K., Goharshady, A. K., & Pourdamghani, A. (2019). Probabilistic smart contracts: Secure randomness on the blockchain. In IEEE International Conference on Blockchain and Cryptocurrency. Seoul, Korea: IEEE. https://doi.org/10.1109/BLOC.2019.8751326","ama":"Chatterjee K, Goharshady AK, Pourdamghani A. Probabilistic smart contracts: Secure randomness on the blockchain. In: IEEE International Conference on Blockchain and Cryptocurrency. IEEE; 2019. doi:10.1109/BLOC.2019.8751326","ieee":"K. Chatterjee, A. K. Goharshady, and A. Pourdamghani, “Probabilistic smart contracts: Secure randomness on the blockchain,” in IEEE International Conference on Blockchain and Cryptocurrency, Seoul, Korea, 2019.","short":"K. Chatterjee, A.K. Goharshady, A. Pourdamghani, in:, IEEE International Conference on Blockchain and Cryptocurrency, IEEE, 2019.","mla":"Chatterjee, Krishnendu, et al. “Probabilistic Smart Contracts: Secure Randomness on the Blockchain.” IEEE International Conference on Blockchain and Cryptocurrency, 8751326, IEEE, 2019, doi:10.1109/BLOC.2019.8751326."},"title":"Probabilistic smart contracts: Secure randomness on the blockchain","external_id":{"arxiv":["1902.07986"]},"author":[{"first_name":"Krishnendu","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87","last_name":"Chatterjee","orcid":"0000-0002-4561-241X","full_name":"Chatterjee, Krishnendu"},{"first_name":"Amir Kafshdar","id":"391365CE-F248-11E8-B48F-1D18A9856A87","last_name":"Goharshady","full_name":"Goharshady, Amir Kafshdar","orcid":"0000-0003-1702-6584"},{"last_name":"Pourdamghani","full_name":"Pourdamghani, Arash","first_name":"Arash"}],"article_number":"8751326","project":[{"_id":"25892FC0-B435-11E9-9278-68D0E5697425","name":"Efficient Algorithms for Computer Aided Verification","grant_number":"ICT15-003"},{"_id":"25832EC2-B435-11E9-9278-68D0E5697425","call_identifier":"FWF","grant_number":"S 11407_N23","name":"Rigorous Systems Engineering"},{"grant_number":"279307","name":"Quantitative Graph Games: Theory and Applications","call_identifier":"FP7","_id":"2581B60A-B435-11E9-9278-68D0E5697425"},{"name":"Quantitative Game-theoretic Analysis of Blockchain Applications and Smart Contracts","_id":"266EEEC0-B435-11E9-9278-68D0E5697425"},{"_id":"267066CE-B435-11E9-9278-68D0E5697425","name":"Quantitative Analysis of Probablistic Systems with a focus on Crypto-currencies"}],"publication":"IEEE International Conference on Blockchain and Cryptocurrency","day":"01","year":"2019","date_created":"2019-02-26T09:03:15Z","date_published":"2019-05-01T00:00:00Z","doi":"10.1109/BLOC.2019.8751326","oa":1,"quality_controlled":"1","publisher":"IEEE"},{"file_date_updated":"2020-07-14T12:47:29Z","department":[{"_id":"KrCh"}],"date_updated":"2024-03-27T23:30:33Z","ddc":["004"],"type":"conference","conference":{"name":"ACM Symposium on Applied Computing","location":"Limassol, Cyprus","end_date":"2019-04-12","start_date":"2019-04-08"},"status":"public","pubrep_id":"1069","_id":"6378","related_material":{"record":[{"id":"8934","status":"public","relation":"dissertation_contains"}]},"volume":"Part F147772","ec_funded":1,"publication_identifier":{"isbn":["9781450359337"]},"publication_status":"published","file":[{"file_name":"2019_ACM_Chatterjee.pdf","date_created":"2019-05-06T12:09:27Z","file_size":1023934,"date_updated":"2020-07-14T12:47:29Z","creator":"dernst","checksum":"fbfbcd5a0c7a743862bfc3045539a614","file_id":"6379","content_type":"application/pdf","relation":"main_file","access_level":"open_access"}],"language":[{"iso":"eng"}],"scopus_import":"1","month":"04","abstract":[{"text":"In today's cryptocurrencies, Hashcash proof of work is the most commonly-adopted approach to mining. In Hashcash, when a miner decides to add a block to the chain, she has to solve the difficult computational puzzle of inverting a hash function. While Hashcash has been successfully adopted in both Bitcoin and Ethereum, it has attracted significant and harsh criticism due to its massive waste of electricity, its carbon footprint and environmental effects, and the inherent lack of usefulness in inverting a hash function. Various other mining protocols have been suggested, including proof of stake, in which a miner's chance of adding the next block is proportional to her current balance. However, such protocols lead to a higher entry cost for new miners who might not still have any stake in the cryptocurrency, and can in the worst case lead to an oligopoly, where the rich have complete control over mining. In this paper, we propose Hybrid Mining: a new mining protocol that combines solving real-world useful problems with Hashcash. Our protocol allows new miners to join the network by taking part in Hashcash mining without having to own an initial stake. It also allows nodes of the network to submit hard computational problems whose solutions are of interest in the real world, e.g.~protein folding problems. Then, miners can choose to compete in solving these problems, in lieu of Hashcash, for adding a new block. Hence, Hybrid Mining incentivizes miners to solve useful problems, such as hard computational problems arising in biology, in a distributed manner. It also gives researchers in other areas an easy-to-use tool to outsource their hard computations to the blockchain network, which has enormous computational power, by paying a reward to the miner who solves the problem for them. Moreover, our protocol provides strong security guarantees and is at least as resilient to double spending as Bitcoin.","lang":"eng"}],"oa_version":"Submitted Version","author":[{"first_name":"Krishnendu","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87","last_name":"Chatterjee","orcid":"0000-0002-4561-241X","full_name":"Chatterjee, Krishnendu"},{"first_name":"Amir Kafshdar","id":"391365CE-F248-11E8-B48F-1D18A9856A87","last_name":"Goharshady","orcid":"0000-0003-1702-6584","full_name":"Goharshady, Amir Kafshdar"},{"first_name":"Arash","full_name":"Pourdamghani, Arash","last_name":"Pourdamghani"}],"external_id":{"isi":["000474685800049"]},"article_processing_charge":"No","title":"Hybrid Mining: Exploiting blockchain’s computational power for distributed problem solving","citation":{"ama":"Chatterjee K, Goharshady AK, Pourdamghani A. Hybrid Mining: Exploiting blockchain’s computational power for distributed problem solving. In: Proceedings of the 34th ACM Symposium on Applied Computing. Vol Part F147772. ACM; 2019:374-381. doi:10.1145/3297280.3297319","apa":"Chatterjee, K., Goharshady, A. K., & Pourdamghani, A. (2019). Hybrid Mining: Exploiting blockchain’s computational power for distributed problem solving. In Proceedings of the 34th ACM Symposium on Applied Computing (Vol. Part F147772, pp. 374–381). Limassol, Cyprus: ACM. https://doi.org/10.1145/3297280.3297319","ieee":"K. Chatterjee, A. K. Goharshady, and A. Pourdamghani, “Hybrid Mining: Exploiting blockchain’s computational power for distributed problem solving,” in Proceedings of the 34th ACM Symposium on Applied Computing, Limassol, Cyprus, 2019, vol. Part F147772, pp. 374–381.","short":"K. Chatterjee, A.K. Goharshady, A. Pourdamghani, in:, Proceedings of the 34th ACM Symposium on Applied Computing, ACM, 2019, pp. 374–381.","mla":"Chatterjee, Krishnendu, et al. “Hybrid Mining: Exploiting Blockchain’s Computational Power for Distributed Problem Solving.” Proceedings of the 34th ACM Symposium on Applied Computing, vol. Part F147772, ACM, 2019, pp. 374–81, doi:10.1145/3297280.3297319.","ista":"Chatterjee K, Goharshady AK, Pourdamghani A. 2019. Hybrid Mining: Exploiting blockchain’s computational power for distributed problem solving. Proceedings of the 34th ACM Symposium on Applied Computing. ACM Symposium on Applied Computing vol. Part F147772, 374–381.","chicago":"Chatterjee, Krishnendu, Amir Kafshdar Goharshady, and Arash Pourdamghani. “Hybrid Mining: Exploiting Blockchain’s Computational Power for Distributed Problem Solving.” In Proceedings of the 34th ACM Symposium on Applied Computing, Part F147772:374–81. ACM, 2019. https://doi.org/10.1145/3297280.3297319."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","project":[{"call_identifier":"FP7","_id":"2581B60A-B435-11E9-9278-68D0E5697425","name":"Quantitative Graph Games: Theory and Applications","grant_number":"279307"},{"name":"Efficient Algorithms for Computer Aided Verification","grant_number":"ICT15-003","_id":"25892FC0-B435-11E9-9278-68D0E5697425"},{"call_identifier":"FWF","_id":"25832EC2-B435-11E9-9278-68D0E5697425","name":"Rigorous Systems Engineering","grant_number":"S 11407_N23"}],"page":"374-381","date_published":"2019-04-01T00:00:00Z","doi":"10.1145/3297280.3297319","date_created":"2019-05-06T12:11:36Z","isi":1,"has_accepted_license":"1","year":"2019","day":"01","publication":"Proceedings of the 34th ACM Symposium on Applied Computing","publisher":"ACM","quality_controlled":"1","oa":1},{"month":"06","scopus_import":"1","oa_version":"Submitted Version","abstract":[{"text":"We consider the problem of expected cost analysis over nondeterministic probabilistic programs,\r\nwhich aims at automated methods for analyzing the resource-usage of such programs.\r\nPrevious approaches for this problem could only handle nonnegative bounded costs.\r\nHowever, in many scenarios, such as queuing networks or analysis of cryptocurrency protocols,\r\nboth positive and negative costs are necessary and the costs are unbounded as well.\r\n\r\nIn this work, we present a sound and efficient approach to obtain polynomial bounds on the\r\nexpected accumulated cost of nondeterministic probabilistic programs.\r\nOur approach can handle (a) general positive and negative costs with bounded updates in\r\nvariables; and (b) nonnegative costs with general updates to variables.\r\nWe show that several natural examples which could not be\r\nhandled by previous approaches are captured in our framework.\r\n\r\nMoreover, our approach leads to an efficient polynomial-time algorithm, while no\r\nprevious approach for cost analysis of probabilistic programs could guarantee polynomial runtime.\r\nFinally, we show the effectiveness of our approach using experimental results on a variety of programs for which we efficiently synthesize tight resource-usage bounds.","lang":"eng"}],"related_material":{"record":[{"relation":"earlier_version","id":"5457","status":"public"},{"relation":"dissertation_contains","status":"public","id":"8934"}]},"ec_funded":1,"file":[{"date_created":"2019-03-25T10:11:22Z","file_name":"paper.pdf","creator":"akafshda","date_updated":"2020-07-14T12:47:20Z","file_size":4051066,"file_id":"6176","checksum":"703a5e9b8c8587f2a44085ffd9a4db64","access_level":"open_access","relation":"main_file","content_type":"application/pdf"}],"language":[{"iso":"eng"}],"publication_status":"published","status":"public","keyword":["Program Cost Analysis","Program Termination","Probabilistic Programs","Martingales"],"type":"conference","conference":{"start_date":"2019-06-22","location":"Phoenix, AZ, United States","end_date":"2019-06-26","name":"PLDI: Conference on Programming Language Design and Implementation"},"_id":"6175","file_date_updated":"2020-07-14T12:47:20Z","department":[{"_id":"KrCh"}],"ddc":["000"],"date_updated":"2024-03-27T23:30:33Z","publisher":"Association for Computing Machinery","quality_controlled":"1","oa":1,"doi":"10.1145/3314221.3314581","date_published":"2019-06-08T00:00:00Z","date_created":"2019-03-25T10:13:25Z","page":"204-220","day":"08","publication":"PLDI 2019: Proceedings of the 40th ACM SIGPLAN Conference on Programming Language Design and Implementation","has_accepted_license":"1","isi":1,"year":"2019","project":[{"_id":"25892FC0-B435-11E9-9278-68D0E5697425","grant_number":"ICT15-003","name":"Efficient Algorithms for Computer Aided Verification"},{"name":"Game Theory","grant_number":"S11407","_id":"25863FF4-B435-11E9-9278-68D0E5697425","call_identifier":"FWF"},{"grant_number":"S 11407_N23","name":"Rigorous Systems Engineering","call_identifier":"FWF","_id":"25832EC2-B435-11E9-9278-68D0E5697425"},{"_id":"2581B60A-B435-11E9-9278-68D0E5697425","call_identifier":"FP7","name":"Quantitative Graph Games: Theory and Applications","grant_number":"279307"},{"name":"Quantitative Game-theoretic Analysis of Blockchain Applications and Smart Contracts","_id":"266EEEC0-B435-11E9-9278-68D0E5697425"}],"title":"Cost analysis of nondeterministic probabilistic programs","author":[{"first_name":"Peixin","last_name":"Wang","full_name":"Wang, Peixin"},{"last_name":"Fu","full_name":"Fu, Hongfei","first_name":"Hongfei","id":"3AAD03D6-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Goharshady","full_name":"Goharshady, Amir Kafshdar","orcid":"0000-0003-1702-6584","id":"391365CE-F248-11E8-B48F-1D18A9856A87","first_name":"Amir Kafshdar"},{"first_name":"Krishnendu","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87","full_name":"Chatterjee, Krishnendu","orcid":"0000-0002-4561-241X","last_name":"Chatterjee"},{"first_name":"Xudong","full_name":"Qin, Xudong","last_name":"Qin"},{"first_name":"Wenjun","last_name":"Shi","full_name":"Shi, Wenjun"}],"article_processing_charge":"No","external_id":{"isi":["000523190300014"],"arxiv":["1902.04659"]},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"chicago":"Wang, Peixin, Hongfei Fu, Amir Kafshdar Goharshady, Krishnendu Chatterjee, Xudong Qin, and Wenjun Shi. “Cost Analysis of Nondeterministic Probabilistic Programs.” In PLDI 2019: Proceedings of the 40th ACM SIGPLAN Conference on Programming Language Design and Implementation, 204–20. Association for Computing Machinery, 2019. https://doi.org/10.1145/3314221.3314581.","ista":"Wang P, Fu H, Goharshady AK, Chatterjee K, Qin X, Shi W. 2019. Cost analysis of nondeterministic probabilistic programs. PLDI 2019: Proceedings of the 40th ACM SIGPLAN Conference on Programming Language Design and Implementation. PLDI: Conference on Programming Language Design and Implementation, 204–220.","mla":"Wang, Peixin, et al. “Cost Analysis of Nondeterministic Probabilistic Programs.” PLDI 2019: Proceedings of the 40th ACM SIGPLAN Conference on Programming Language Design and Implementation, Association for Computing Machinery, 2019, pp. 204–20, doi:10.1145/3314221.3314581.","ieee":"P. Wang, H. Fu, A. K. Goharshady, K. Chatterjee, X. Qin, and W. Shi, “Cost analysis of nondeterministic probabilistic programs,” in PLDI 2019: Proceedings of the 40th ACM SIGPLAN Conference on Programming Language Design and Implementation, Phoenix, AZ, United States, 2019, pp. 204–220.","short":"P. Wang, H. Fu, A.K. Goharshady, K. Chatterjee, X. Qin, W. Shi, in:, PLDI 2019: Proceedings of the 40th ACM SIGPLAN Conference on Programming Language Design and Implementation, Association for Computing Machinery, 2019, pp. 204–220.","ama":"Wang P, Fu H, Goharshady AK, Chatterjee K, Qin X, Shi W. Cost analysis of nondeterministic probabilistic programs. In: PLDI 2019: Proceedings of the 40th ACM SIGPLAN Conference on Programming Language Design and Implementation. Association for Computing Machinery; 2019:204-220. doi:10.1145/3314221.3314581","apa":"Wang, P., Fu, H., Goharshady, A. K., Chatterjee, K., Qin, X., & Shi, W. (2019). Cost analysis of nondeterministic probabilistic programs. In PLDI 2019: Proceedings of the 40th ACM SIGPLAN Conference on Programming Language Design and Implementation (pp. 204–220). Phoenix, AZ, United States: Association for Computing Machinery. https://doi.org/10.1145/3314221.3314581"}},{"year":"2019","has_accepted_license":"1","isi":1,"publication":"Proceedings of the 34th ACM Symposium on Applied Computing","day":"01","page":"400-408","date_created":"2019-05-26T21:59:15Z","date_published":"2019-04-01T00:00:00Z","doi":"10.1145/3297280.3297322","oa":1,"publisher":"ACM","quality_controlled":"1","citation":{"chicago":"Chatterjee, Krishnendu, Amir Kafshdar Goharshady, and Ehsan Kafshdar Goharshady. “The Treewidth of Smart Contracts.” In Proceedings of the 34th ACM Symposium on Applied Computing, Part F147772:400–408. ACM, n.d. https://doi.org/10.1145/3297280.3297322.","ista":"Chatterjee K, Goharshady AK, Goharshady EK. The treewidth of smart contracts. Proceedings of the 34th ACM Symposium on Applied Computing. SAC: Symposium on Applied Computing vol. Part F147772, 400–408.","mla":"Chatterjee, Krishnendu, et al. “The Treewidth of Smart Contracts.” Proceedings of the 34th ACM Symposium on Applied Computing, vol. Part F147772, ACM, pp. 400–08, doi:10.1145/3297280.3297322.","short":"K. Chatterjee, A.K. Goharshady, E.K. Goharshady, in:, Proceedings of the 34th ACM Symposium on Applied Computing, ACM, n.d., pp. 400–408.","ieee":"K. Chatterjee, A. K. Goharshady, and E. K. Goharshady, “The treewidth of smart contracts,” in Proceedings of the 34th ACM Symposium on Applied Computing, Limassol, Cyprus, vol. Part F147772, pp. 400–408.","apa":"Chatterjee, K., Goharshady, A. K., & Goharshady, E. K. (n.d.). The treewidth of smart contracts. In Proceedings of the 34th ACM Symposium on Applied Computing (Vol. Part F147772, pp. 400–408). Limassol, Cyprus: ACM. https://doi.org/10.1145/3297280.3297322","ama":"Chatterjee K, Goharshady AK, Goharshady EK. The treewidth of smart contracts. In: Proceedings of the 34th ACM Symposium on Applied Computing. Vol Part F147772. ACM; :400-408. doi:10.1145/3297280.3297322"},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","external_id":{"isi":["000474685800052"]},"article_processing_charge":"No","author":[{"first_name":"Krishnendu","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0002-4561-241X","full_name":"Chatterjee, Krishnendu","last_name":"Chatterjee"},{"last_name":"Goharshady","full_name":"Goharshady, Amir Kafshdar","orcid":"0000-0003-1702-6584","first_name":"Amir Kafshdar","id":"391365CE-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Ehsan Kafshdar","last_name":"Goharshady","full_name":"Goharshady, Ehsan Kafshdar"}],"title":"The treewidth of smart contracts","publication_status":"submitted","publication_identifier":{"isbn":["9781450359337"]},"language":[{"iso":"eng"}],"file":[{"file_id":"7827","checksum":"dddc20f6d9881f23b8755eb720ec9d6f","relation":"main_file","access_level":"open_access","content_type":"application/pdf","file_name":"2019_ACM_Chatterjee.pdf","date_created":"2020-05-14T09:50:11Z","creator":"dernst","file_size":6937138,"date_updated":"2020-07-14T12:47:32Z"}],"related_material":{"record":[{"id":"8934","status":"public","relation":"dissertation_contains"}]},"volume":"Part F147772","abstract":[{"text":"Smart contracts are programs that are stored and executed on the Blockchain and can receive, manage and transfer money (cryptocurrency units). Two important problems regarding smart contracts are formal analysis and compiler optimization. Formal analysis is extremely important, because smart contracts hold funds worth billions of dollars and their code is immutable after deployment. Hence, an undetected bug can cause significant financial losses. Compiler optimization is also crucial, because every action of a smart contract has to be executed by every node in the Blockchain network. Therefore, optimizations in compiling smart contracts can lead to significant savings in computation, time and energy.\r\n\r\nTwo classical approaches in program analysis and compiler optimization are intraprocedural and interprocedural analysis. In intraprocedural analysis, each function is analyzed separately, while interprocedural analysis considers the entire program. In both cases, the analyses are usually reduced to graph problems over the control flow graph (CFG) of the program. These graph problems are often computationally expensive. Hence, there has been ample research on exploiting structural properties of CFGs for efficient algorithms. One such well-studied property is the treewidth, which is a measure of tree-likeness of graphs. It is known that intraprocedural CFGs of structured programs have treewidth at most 6, whereas the interprocedural treewidth cannot be bounded. This result has been used as a basis for many efficient intraprocedural analyses.\r\n\r\nIn this paper, we explore the idea of exploiting the treewidth of smart contracts for formal analysis and compiler optimization. First, similar to classical programs, we show that the intraprocedural treewidth of structured Solidity and Vyper smart contracts is at most 9. Second, for global analysis, we prove that the interprocedural treewidth of structured smart contracts is bounded by 10 and, in sharp contrast with classical programs, treewidth-based algorithms can be easily applied for interprocedural analysis. Finally, we supplement our theoretical results with experiments using a tool we implemented for computing treewidth of smart contracts and show that the treewidth is much lower in practice. We use 36,764 real-world Ethereum smart contracts as benchmarks and find that they have an average treewidth of at most 3.35 for the intraprocedural case and 3.65 for the interprocedural case.\r\n","lang":"eng"}],"oa_version":"Submitted Version","scopus_import":"1","month":"04","date_updated":"2024-03-27T23:30:33Z","ddc":["000"],"file_date_updated":"2020-07-14T12:47:32Z","department":[{"_id":"KrCh"}],"_id":"6490","conference":{"start_date":"2019-04-08","location":"Limassol, Cyprus","end_date":"2019-04-12","name":"SAC: Symposium on Applied Computing"},"type":"conference","pubrep_id":"1070","status":"public"},{"scopus_import":"1","month":"11","intvolume":" 41","abstract":[{"text":"Interprocedural analysis is at the heart of numerous applications in programming languages, such as alias analysis, constant propagation, and so on. Recursive state machines (RSMs) are standard models for interprocedural analysis. We consider a general framework with RSMs where the transitions are labeled from a semiring and path properties are algebraic with semiring operations. RSMs with algebraic path properties can model interprocedural dataflow analysis problems, the shortest path problem, the most probable path problem, and so on. The traditional algorithms for interprocedural analysis focus on path properties where the starting point is fixed as the entry point of a specific method. In this work, we consider possible multiple queries as required in many applications such as in alias analysis. The study of multiple queries allows us to bring in an important algorithmic distinction between the resource usage of the one-time preprocessing vs for each individual query. The second aspect we consider is that the control flow graphs for most programs have constant treewidth.\r\n\r\nOur main contributions are simple and implementable algorithms that support multiple queries for algebraic path properties for RSMs that have constant treewidth. Our theoretical results show that our algorithms have small additional one-time preprocessing but can answer subsequent queries significantly faster as compared to the current algorithmic solutions for interprocedural dataflow analysis. We have also implemented our algorithms and evaluated their performance for performing on-demand interprocedural dataflow analysis on various domains, such as for live variable analysis and reaching definitions, on a standard benchmark set. Our experimental results align with our theoretical statements and show that after a lightweight preprocessing, on-demand queries are answered much faster than the standard existing algorithmic approaches.\r\n","lang":"eng"}],"oa_version":"Submitted Version","volume":41,"related_material":{"record":[{"status":"public","id":"8934","relation":"dissertation_contains"}]},"issue":"4","ec_funded":1,"publication_identifier":{"issn":["0164-0925"]},"publication_status":"published","file":[{"date_updated":"2020-10-08T12:58:10Z","file_size":667357,"creator":"dernst","date_created":"2020-10-08T12:58:10Z","file_name":"2019_ACMTransactions_Chatterjee.pdf","content_type":"application/pdf","access_level":"open_access","relation":"main_file","file_id":"8632","checksum":"291cc86a07bd010d4815e177dac57b70","success":1}],"language":[{"iso":"eng"}],"article_type":"original","type":"journal_article","status":"public","_id":"7158","file_date_updated":"2020-10-08T12:58:10Z","department":[{"_id":"KrCh"}],"date_updated":"2024-03-27T23:30:34Z","ddc":["000"],"publisher":"ACM","quality_controlled":"1","oa":1,"date_published":"2019-11-01T00:00:00Z","doi":"10.1145/3363525","date_created":"2019-12-09T08:33:33Z","isi":1,"has_accepted_license":"1","year":"2019","day":"01","publication":"ACM Transactions on Programming Languages and Systems","project":[{"_id":"2584A770-B435-11E9-9278-68D0E5697425","call_identifier":"FWF","name":"Modern Graph Algorithmic Techniques in Formal Verification","grant_number":"P 23499-N23"},{"grant_number":"S11407","name":"Game Theory","_id":"25863FF4-B435-11E9-9278-68D0E5697425","call_identifier":"FWF"},{"name":"Quantitative Graph Games: Theory and Applications","grant_number":"279307","_id":"2581B60A-B435-11E9-9278-68D0E5697425","call_identifier":"FP7"}],"article_number":"23","author":[{"first_name":"Krishnendu","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87","last_name":"Chatterjee","orcid":"0000-0002-4561-241X","full_name":"Chatterjee, Krishnendu"},{"last_name":"Goharshady","full_name":"Goharshady, Amir Kafshdar","orcid":"0000-0003-1702-6584","id":"391365CE-F248-11E8-B48F-1D18A9856A87","first_name":"Amir Kafshdar"},{"first_name":"Prateesh","last_name":"Goyal","full_name":"Goyal, Prateesh"},{"id":"3B699956-F248-11E8-B48F-1D18A9856A87","first_name":"Rasmus","last_name":"Ibsen-Jensen","full_name":"Ibsen-Jensen, Rasmus","orcid":"0000-0003-4783-0389"},{"orcid":"0000-0002-8943-0722","full_name":"Pavlogiannis, Andreas","last_name":"Pavlogiannis","id":"49704004-F248-11E8-B48F-1D18A9856A87","first_name":"Andreas"}],"article_processing_charge":"No","external_id":{"isi":["000564108400004"]},"title":"Faster algorithms for dynamic algebraic queries in basic RSMs with constant treewidth","citation":{"mla":"Chatterjee, Krishnendu, et al. “Faster Algorithms for Dynamic Algebraic Queries in Basic RSMs with Constant Treewidth.” ACM Transactions on Programming Languages and Systems, vol. 41, no. 4, 23, ACM, 2019, doi:10.1145/3363525.","short":"K. Chatterjee, A.K. Goharshady, P. Goyal, R. Ibsen-Jensen, A. Pavlogiannis, ACM Transactions on Programming Languages and Systems 41 (2019).","ieee":"K. Chatterjee, A. K. Goharshady, P. Goyal, R. Ibsen-Jensen, and A. Pavlogiannis, “Faster algorithms for dynamic algebraic queries in basic RSMs with constant treewidth,” ACM Transactions on Programming Languages and Systems, vol. 41, no. 4. ACM, 2019.","apa":"Chatterjee, K., Goharshady, A. K., Goyal, P., Ibsen-Jensen, R., & Pavlogiannis, A. (2019). Faster algorithms for dynamic algebraic queries in basic RSMs with constant treewidth. ACM Transactions on Programming Languages and Systems. ACM. https://doi.org/10.1145/3363525","ama":"Chatterjee K, Goharshady AK, Goyal P, Ibsen-Jensen R, Pavlogiannis A. Faster algorithms for dynamic algebraic queries in basic RSMs with constant treewidth. ACM Transactions on Programming Languages and Systems. 2019;41(4). doi:10.1145/3363525","chicago":"Chatterjee, Krishnendu, Amir Kafshdar Goharshady, Prateesh Goyal, Rasmus Ibsen-Jensen, and Andreas Pavlogiannis. “Faster Algorithms for Dynamic Algebraic Queries in Basic RSMs with Constant Treewidth.” ACM Transactions on Programming Languages and Systems. ACM, 2019. https://doi.org/10.1145/3363525.","ista":"Chatterjee K, Goharshady AK, Goyal P, Ibsen-Jensen R, Pavlogiannis A. 2019. Faster algorithms for dynamic algebraic queries in basic RSMs with constant treewidth. ACM Transactions on Programming Languages and Systems. 41(4), 23."},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1"},{"article_type":"original","type":"journal_article","status":"public","_id":"7014","department":[{"_id":"KrCh"}],"date_updated":"2024-03-27T23:30:33Z","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1705.00317"}],"scopus_import":"1","intvolume":" 41","month":"10","abstract":[{"text":"We study the problem of developing efficient approaches for proving\r\nworst-case bounds of non-deterministic recursive programs. Ranking functions\r\nare sound and complete for proving termination and worst-case bounds of\r\nnonrecursive programs. First, we apply ranking functions to recursion,\r\nresulting in measure functions. We show that measure functions provide a sound\r\nand complete approach to prove worst-case bounds of non-deterministic recursive\r\nprograms. Our second contribution is the synthesis of measure functions in\r\nnonpolynomial forms. We show that non-polynomial measure functions with\r\nlogarithm and exponentiation can be synthesized through abstraction of\r\nlogarithmic or exponentiation terms, Farkas' Lemma, and Handelman's Theorem\r\nusing linear programming. While previous methods obtain worst-case polynomial\r\nbounds, our approach can synthesize bounds of the form $\\mathcal{O}(n\\log n)$\r\nas well as $\\mathcal{O}(n^r)$ where $r$ is not an integer. We present\r\nexperimental results to demonstrate that our approach can obtain efficiently\r\nworst-case bounds of classical recursive algorithms such as (i) Merge-Sort, the\r\ndivide-and-conquer algorithm for the Closest-Pair problem, where we obtain\r\n$\\mathcal{O}(n \\log n)$ worst-case bound, and (ii) Karatsuba's algorithm for\r\npolynomial multiplication and Strassen's algorithm for matrix multiplication,\r\nwhere we obtain $\\mathcal{O}(n^r)$ bound such that $r$ is not an integer and\r\nclose to the best-known bounds for the respective algorithms.","lang":"eng"}],"oa_version":"Preprint","ec_funded":1,"issue":"4","volume":41,"related_material":{"record":[{"id":"639","status":"public","relation":"earlier_version"},{"relation":"dissertation_contains","id":"8934","status":"public"}]},"publication_status":"published","language":[{"iso":"eng"}],"project":[{"grant_number":"ICT15-003","name":"Efficient Algorithms for Computer Aided Verification","_id":"25892FC0-B435-11E9-9278-68D0E5697425"},{"_id":"25832EC2-B435-11E9-9278-68D0E5697425","call_identifier":"FWF","grant_number":"S 11407_N23","name":"Rigorous Systems Engineering"},{"_id":"2581B60A-B435-11E9-9278-68D0E5697425","call_identifier":"FP7","name":"Quantitative Graph Games: Theory and Applications","grant_number":"279307"},{"_id":"267066CE-B435-11E9-9278-68D0E5697425","name":"Quantitative Analysis of Probablistic Systems with a focus on Crypto-currencies"},{"name":"Quantitative Game-theoretic Analysis of Blockchain Applications and Smart Contracts","_id":"266EEEC0-B435-11E9-9278-68D0E5697425"}],"article_number":"20","external_id":{"arxiv":["1705.00317"],"isi":["000564108400001"]},"article_processing_charge":"No","author":[{"last_name":"Chatterjee","orcid":"0000-0002-4561-241X","full_name":"Chatterjee, Krishnendu","first_name":"Krishnendu","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Fu","full_name":"Fu, Hongfei","first_name":"Hongfei"},{"first_name":"Amir Kafshdar","id":"391365CE-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0003-1702-6584","full_name":"Goharshady, Amir Kafshdar","last_name":"Goharshady"}],"title":"Non-polynomial worst-case analysis of recursive programs","citation":{"chicago":"Chatterjee, Krishnendu, Hongfei Fu, and Amir Kafshdar Goharshady. “Non-Polynomial Worst-Case Analysis of Recursive Programs.” ACM Transactions on Programming Languages and Systems. ACM, 2019. https://doi.org/10.1145/3339984.","ista":"Chatterjee K, Fu H, Goharshady AK. 2019. Non-polynomial worst-case analysis of recursive programs. ACM Transactions on Programming Languages and Systems. 41(4), 20.","mla":"Chatterjee, Krishnendu, et al. “Non-Polynomial Worst-Case Analysis of Recursive Programs.” ACM Transactions on Programming Languages and Systems, vol. 41, no. 4, 20, ACM, 2019, doi:10.1145/3339984.","ama":"Chatterjee K, Fu H, Goharshady AK. Non-polynomial worst-case analysis of recursive programs. ACM Transactions on Programming Languages and Systems. 2019;41(4). doi:10.1145/3339984","apa":"Chatterjee, K., Fu, H., & Goharshady, A. K. (2019). Non-polynomial worst-case analysis of recursive programs. ACM Transactions on Programming Languages and Systems. ACM. https://doi.org/10.1145/3339984","ieee":"K. Chatterjee, H. Fu, and A. K. Goharshady, “Non-polynomial worst-case analysis of recursive programs,” ACM Transactions on Programming Languages and Systems, vol. 41, no. 4. ACM, 2019.","short":"K. Chatterjee, H. Fu, A.K. Goharshady, ACM Transactions on Programming Languages and Systems 41 (2019)."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","oa":1,"quality_controlled":"1","publisher":"ACM","date_created":"2019-11-13T08:33:43Z","date_published":"2019-10-01T00:00:00Z","doi":"10.1145/3339984","year":"2019","isi":1,"publication":"ACM Transactions on Programming Languages and Systems","day":"01"},{"project":[{"grant_number":"306589","name":"Decoding the complexity of turbulence at its origin","_id":"25152F3A-B435-11E9-9278-68D0E5697425","call_identifier":"FP7"}],"article_number":"111105","title":"Relaminarization of pipe flow by means of 3D-printed shaped honeycombs","author":[{"last_name":"Kühnen","full_name":"Kühnen, Jakob","orcid":"0000-0003-4312-0179","id":"3A47AE32-F248-11E8-B48F-1D18A9856A87","first_name":"Jakob"},{"first_name":"Davide","id":"40315C30-F248-11E8-B48F-1D18A9856A87","last_name":"Scarselli","orcid":"0000-0001-5227-4271","full_name":"Scarselli, Davide"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof"}],"external_id":{"isi":["000487748600005"],"arxiv":["1809.07625"]},"article_processing_charge":"No","user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"chicago":"Kühnen, Jakob, Davide Scarselli, and Björn Hof. “Relaminarization of Pipe Flow by Means of 3D-Printed Shaped Honeycombs.” Journal of Fluids Engineering. ASME, 2019. https://doi.org/10.1115/1.4043494.","ista":"Kühnen J, Scarselli D, Hof B. 2019. Relaminarization of pipe flow by means of 3D-printed shaped honeycombs. Journal of Fluids Engineering. 141(11), 111105.","mla":"Kühnen, Jakob, et al. “Relaminarization of Pipe Flow by Means of 3D-Printed Shaped Honeycombs.” Journal of Fluids Engineering, vol. 141, no. 11, 111105, ASME, 2019, doi:10.1115/1.4043494.","apa":"Kühnen, J., Scarselli, D., & Hof, B. (2019). Relaminarization of pipe flow by means of 3D-printed shaped honeycombs. Journal of Fluids Engineering. ASME. https://doi.org/10.1115/1.4043494","ama":"Kühnen J, Scarselli D, Hof B. Relaminarization of pipe flow by means of 3D-printed shaped honeycombs. Journal of Fluids Engineering. 2019;141(11). doi:10.1115/1.4043494","short":"J. Kühnen, D. Scarselli, B. Hof, Journal of Fluids Engineering 141 (2019).","ieee":"J. Kühnen, D. Scarselli, and B. Hof, “Relaminarization of pipe flow by means of 3D-printed shaped honeycombs,” Journal of Fluids Engineering, vol. 141, no. 11. ASME, 2019."},"quality_controlled":"1","publisher":"ASME","oa":1,"date_published":"2019-11-01T00:00:00Z","doi":"10.1115/1.4043494","date_created":"2019-05-26T21:59:13Z","day":"01","publication":"Journal of Fluids Engineering","isi":1,"year":"2019","status":"public","article_type":"original","type":"journal_article","_id":"6486","department":[{"_id":"BjHo"}],"date_updated":"2024-03-27T23:30:35Z","month":"11","intvolume":" 141","scopus_import":"1","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1809.07625"}],"oa_version":"Preprint","abstract":[{"text":"Based on a novel control scheme, where a steady modification of the streamwise velocity profile leads to complete relaminarization of initially fully turbulent pipe flow, we investigate the applicability and usefulness of custom-shaped honeycombs for such control. The custom-shaped honeycombs are used as stationary flow management devices which generate specific modifications of the streamwise velocity profile. Stereoscopic particle image velocimetry and pressure drop measurements are used to investigate and capture the development of the relaminarizing flow downstream these devices. We compare the performance of straight (constant length across the radius of the pipe) honeycombs with custom-shaped ones (variable length across the radius) and try to determine the optimal shape for maximal relaminarization at minimal pressure loss. The optimally modified streamwise velocity profile is found to be M-shaped, and the maximum attainable Reynolds number for total relaminarization is found to be of the order of 10,000. Consequently, the respective reduction in skin friction downstream of the device is almost by a factor of 5. The break-even point, where the additional pressure drop caused by the device is balanced by the savings due to relaminarization and a net gain is obtained, corresponds to a downstream stretch of distances as low as approximately 100 pipe diameters of laminar flow.","lang":"eng"}],"acknowledged_ssus":[{"_id":"M-Shop"}],"issue":"11","related_material":{"record":[{"relation":"dissertation_contains","id":"7258","status":"public"}]},"volume":141,"ec_funded":1,"language":[{"iso":"eng"}],"publication_identifier":{"issn":["00982202"],"eissn":["1528901X"]},"publication_status":"published"},{"type":"journal_article","status":"public","_id":"6228","department":[{"_id":"BjHo"}],"date_updated":"2024-03-27T23:30:35Z","main_file_link":[{"url":"https://arxiv.org/abs/1807.05357","open_access":"1"}],"scopus_import":"1","intvolume":" 867","month":"05","abstract":[{"lang":"eng","text":"Following the recent observation that turbulent pipe flow can be relaminarised bya relatively simple modification of the mean velocity profile, we here carry out aquantitative experimental investigation of this phenomenon. Our study confirms thata flat velocity profile leads to a collapse of turbulence and in order to achieve theblunted profile shape, we employ a moving pipe segment that is briefly and rapidlyshifted in the streamwise direction. The relaminarisation threshold and the minimumshift length and speeds are determined as a function of Reynolds number. Althoughturbulence is still active after the acceleration phase, the modulated profile possessesa severely decreased lift-up potential as measured by transient growth. As shown,this results in an exponential decay of fluctuations and the flow relaminarises. Whilethis method can be easily applied at low to moderate flow speeds, the minimumstreamwise length over which the acceleration needs to act increases linearly with theReynolds number."}],"oa_version":"Preprint","ec_funded":1,"volume":867,"related_material":{"record":[{"status":"public","id":"7258","relation":"dissertation_contains"}],"link":[{"url":"https://doi.org/10.1017/jfm.2019.191","relation":"supplementary_material"}]},"publication_status":"published","publication_identifier":{"eissn":["14697645"],"issn":["00221120"]},"language":[{"iso":"eng"}],"project":[{"_id":"25152F3A-B435-11E9-9278-68D0E5697425","call_identifier":"FP7","grant_number":"306589","name":"Decoding the complexity of turbulence at its origin"},{"grant_number":"737549","name":"Eliminating turbulence in oil pipelines","call_identifier":"H2020","_id":"25104D44-B435-11E9-9278-68D0E5697425"}],"article_processing_charge":"No","external_id":{"arxiv":["1807.05357"],"isi":["000462606100001"]},"author":[{"id":"40315C30-F248-11E8-B48F-1D18A9856A87","first_name":"Davide","last_name":"Scarselli","full_name":"Scarselli, Davide","orcid":"0000-0001-5227-4271"},{"last_name":"Kühnen","orcid":"0000-0003-4312-0179","full_name":"Kühnen, Jakob","first_name":"Jakob","id":"3A47AE32-F248-11E8-B48F-1D18A9856A87"},{"orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof","first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87"}],"title":"Relaminarising pipe flow by wall movement","citation":{"ista":"Scarselli D, Kühnen J, Hof B. 2019. Relaminarising pipe flow by wall movement. Journal of Fluid Mechanics. 867, 934–948.","chicago":"Scarselli, Davide, Jakob Kühnen, and Björn Hof. “Relaminarising Pipe Flow by Wall Movement.” Journal of Fluid Mechanics. Cambridge University Press, 2019. https://doi.org/10.1017/jfm.2019.191.","ieee":"D. Scarselli, J. Kühnen, and B. Hof, “Relaminarising pipe flow by wall movement,” Journal of Fluid Mechanics, vol. 867. Cambridge University Press, pp. 934–948, 2019.","short":"D. Scarselli, J. Kühnen, B. Hof, Journal of Fluid Mechanics 867 (2019) 934–948.","apa":"Scarselli, D., Kühnen, J., & Hof, B. (2019). Relaminarising pipe flow by wall movement. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2019.191","ama":"Scarselli D, Kühnen J, Hof B. Relaminarising pipe flow by wall movement. Journal of Fluid Mechanics. 2019;867:934-948. doi:10.1017/jfm.2019.191","mla":"Scarselli, Davide, et al. “Relaminarising Pipe Flow by Wall Movement.” Journal of Fluid Mechanics, vol. 867, Cambridge University Press, 2019, pp. 934–48, doi:10.1017/jfm.2019.191."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","oa":1,"quality_controlled":"1","publisher":"Cambridge University Press","page":"934-948","date_created":"2019-04-07T21:59:14Z","doi":"10.1017/jfm.2019.191","date_published":"2019-05-25T00:00:00Z","year":"2019","isi":1,"publication":"Journal of Fluid Mechanics","day":"25"}]