For a property P and a sub-property P', we say that P is P'-partially testable with q queries} if there exists an algorithm that distinguishes, with high probability, inputs in P' from inputs ε-far from P, using q queries. Some natural properties require many queries to test, but can be partitioned into a small number of subsets for which they are partially testable with very few queries, sometimes even a number independent of the input size. For properties over {0,1}, the notion of being thus partitionable ties in closely with Merlin-Arthur proofs of Proximity (MAPs) as defined independently in [14] a partition into r partially-testable properties is the same as a Merlin-Arthur system where the proof consists of the identity of one of the r partially-testable properties, giving a 2-way translation to an O(log r) size proof. Our main result is that for some low complexity properties a partition as above cannot exist, and moreover that for each of our properties there does not exist even a single sub-property featuring both a large size and a query-efficient partial test, in particular improving the lower bound set in [14]. For this we use neither the traditional Yao-type arguments nor the more recent communication complexity method, but open up a new approach for proving lower bounds. First, we use entropy analysis, which allows us to apply our arguments directly to 2-sided tests, thus avoiding the cost of the conversion in [14] from 2-sided to 1-sided tests. Broadly speaking we use "distinguishing instances" of a supposed test to show that a uniformly random choice of a member of the sub-property has "low entropy areas", ultimately leading to it having a low total entropy and hence having a small base set. Additionally, to have our arguments apply to adaptive tests, we use a mechanism of "rearranging" the input bits (through a decision tree that adaptively reads the entire input) to expose the low entropy that would otherwise not be apparent. We also explore the possibility of a connection in the other direction, namely whether the existence of a good partition (or MAP) can lead to a relatively query-efficient standard property test. We provide some preliminary results concerning this question, including a simple lower bound on the possible trade-off. Our second major result is a positive trade-off result for the restricted framework of 1-sided proximity oblivious tests. This is achieved through the construction of a "universal tester" that works the same for all properties admitting the restricted test. Our tester is very related to the notion of sample-based testing (for a non-constant number of queries) as defined by Goldreich and Ron in [13]. In particular it partially resolves an open problem raised by [13].
{"title":"Partial tests, universal tests and decomposability","authors":"E. Fischer, Yonatan Goldhirsh, Oded Lachish","doi":"10.1145/2554797.2554841","DOIUrl":"https://doi.org/10.1145/2554797.2554841","url":null,"abstract":"For a property P and a sub-property P', we say that P is P'-partially testable with q queries} if there exists an algorithm that distinguishes, with high probability, inputs in P' from inputs ε-far from P, using q queries. Some natural properties require many queries to test, but can be partitioned into a small number of subsets for which they are partially testable with very few queries, sometimes even a number independent of the input size. For properties over {0,1}, the notion of being thus partitionable ties in closely with Merlin-Arthur proofs of Proximity (MAPs) as defined independently in [14] a partition into r partially-testable properties is the same as a Merlin-Arthur system where the proof consists of the identity of one of the r partially-testable properties, giving a 2-way translation to an O(log r) size proof. Our main result is that for some low complexity properties a partition as above cannot exist, and moreover that for each of our properties there does not exist even a single sub-property featuring both a large size and a query-efficient partial test, in particular improving the lower bound set in [14]. For this we use neither the traditional Yao-type arguments nor the more recent communication complexity method, but open up a new approach for proving lower bounds. First, we use entropy analysis, which allows us to apply our arguments directly to 2-sided tests, thus avoiding the cost of the conversion in [14] from 2-sided to 1-sided tests. Broadly speaking we use \"distinguishing instances\" of a supposed test to show that a uniformly random choice of a member of the sub-property has \"low entropy areas\", ultimately leading to it having a low total entropy and hence having a small base set. Additionally, to have our arguments apply to adaptive tests, we use a mechanism of \"rearranging\" the input bits (through a decision tree that adaptively reads the entire input) to expose the low entropy that would otherwise not be apparent. We also explore the possibility of a connection in the other direction, namely whether the existence of a good partition (or MAP) can lead to a relatively query-efficient standard property test. We provide some preliminary results concerning this question, including a simple lower bound on the possible trade-off. Our second major result is a positive trade-off result for the restricted framework of 1-sided proximity oblivious tests. This is achieved through the construction of a \"universal tester\" that works the same for all properties admitting the restricted test. Our tester is very related to the notion of sample-based testing (for a non-constant number of queries) as defined by Goldreich and Ron in [13]. In particular it partially resolves an open problem raised by [13].","PeriodicalId":382856,"journal":{"name":"Proceedings of the 5th conference on Innovations in theoretical computer science","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126938521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Antoniadis, Neal Barcelo, Michael Nugent, K. Pruhs, Michele Scquizzato
We initiate the theoretical investigation of energy-efficient circuit design. We assume that the circuit design specifies the circuit layout as well as the supply voltages for the gates. To obtain maximum energy efficiency, the circuit design must balance the conflicting demands of minimizing the energy used per gate, and minimizing the number of gates in the circuit; If the energy supplied to the gates is small, then functional failures are likely, necessitating a circuit layout that is more fault-tolerant, and thus that has more gates. By leveraging previous work on fault-tolerant circuit design, we show general upper and lower bounds on the amount of energy required by a circuit to compute a given relation. We show that some circuits would be asymptotically more energy efficient if heterogeneous supply voltages were allowed, and show that for some circuits the most energy-efficient supply voltages are homogeneous over all gates.
{"title":"Energy-efficient circuit design","authors":"A. Antoniadis, Neal Barcelo, Michael Nugent, K. Pruhs, Michele Scquizzato","doi":"10.1145/2554797.2554826","DOIUrl":"https://doi.org/10.1145/2554797.2554826","url":null,"abstract":"We initiate the theoretical investigation of energy-efficient circuit design. We assume that the circuit design specifies the circuit layout as well as the supply voltages for the gates. To obtain maximum energy efficiency, the circuit design must balance the conflicting demands of minimizing the energy used per gate, and minimizing the number of gates in the circuit; If the energy supplied to the gates is small, then functional failures are likely, necessitating a circuit layout that is more fault-tolerant, and thus that has more gates. By leveraging previous work on fault-tolerant circuit design, we show general upper and lower bounds on the amount of energy required by a circuit to compute a given relation. We show that some circuits would be asymptotically more energy efficient if heterogeneous supply voltages were allowed, and show that for some circuits the most energy-efficient supply voltages are homogeneous over all gates.","PeriodicalId":382856,"journal":{"name":"Proceedings of the 5th conference on Innovations in theoretical computer science","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125246860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jonathan W. Berry, Luke Fostvedt, D. Nordman, C. Phillips, C. Seshadhri, Alyson G. Wilson
Triangle enumeration is a fundamental graph operation. Despite the lack of provably efficient (linear, or slightly super-linear) worst-case algorithms for this problem, practitioners run simple, efficient heuristics to find all triangles in graphs with millions of vertices. How are these heuristics exploiting the structure of these special graphs to provide major speedups in running time? We study one of the most prevalent algorithms used by practitioners. A trivial algorithm enumerates all paths of length 2, and checks if each such path is incident to a triangle. A good heuristic is to enumerate only those paths of length 2 where the middle vertex has the lowest degree. It is easily implemented and is empirically known to give remarkable speedups over the trivial algorithm. We study the behavior of this algorithm over graphs with heavy-tailed degree distributions, a defining feature of real-world graphs. The erased configuration model (ECM) efficiently generates a graph with asymptotically (almost) any desired degree sequence. We show that the expected running time of this algorithm over the distribution of graphs created by the ECM is controlled by the l4/3-norm of the degree sequence. As a corollary of our main theorem, we prove expected linear-time performance for degree sequences following a power law with exponent α ≥ 7/3, and non-trivial speedup whenever α ∈ (2,3).
{"title":"Why do simple algorithms for triangle enumeration work in the real world?","authors":"Jonathan W. Berry, Luke Fostvedt, D. Nordman, C. Phillips, C. Seshadhri, Alyson G. Wilson","doi":"10.1145/2554797.2554819","DOIUrl":"https://doi.org/10.1145/2554797.2554819","url":null,"abstract":"Triangle enumeration is a fundamental graph operation. Despite the lack of provably efficient (linear, or slightly super-linear) worst-case algorithms for this problem, practitioners run simple, efficient heuristics to find all triangles in graphs with millions of vertices. How are these heuristics exploiting the structure of these special graphs to provide major speedups in running time? We study one of the most prevalent algorithms used by practitioners. A trivial algorithm enumerates all paths of length 2, and checks if each such path is incident to a triangle. A good heuristic is to enumerate only those paths of length 2 where the middle vertex has the lowest degree. It is easily implemented and is empirically known to give remarkable speedups over the trivial algorithm. We study the behavior of this algorithm over graphs with heavy-tailed degree distributions, a defining feature of real-world graphs. The erased configuration model (ECM) efficiently generates a graph with asymptotically (almost) any desired degree sequence. We show that the expected running time of this algorithm over the distribution of graphs created by the ECM is controlled by the l4/3-norm of the degree sequence. As a corollary of our main theorem, we prove expected linear-time performance for degree sequences following a power law with exponent α ≥ 7/3, and non-trivial speedup whenever α ∈ (2,3).","PeriodicalId":382856,"journal":{"name":"Proceedings of the 5th conference on Innovations in theoretical computer science","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133998922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Session details: Session 4: 16:00--16:10","authors":"David Xiao","doi":"10.1145/3255056","DOIUrl":"https://doi.org/10.1145/3255056","url":null,"abstract":"","PeriodicalId":382856,"journal":{"name":"Proceedings of the 5th conference on Innovations in theoretical computer science","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125366707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Session details: Session 1: 08:30--8:40","authors":"Kobbi Nissim","doi":"10.1145/3255053","DOIUrl":"https://doi.org/10.1145/3255053","url":null,"abstract":"","PeriodicalId":382856,"journal":{"name":"Proceedings of the 5th conference on Innovations in theoretical computer science","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124384363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We prove new positive and negative results concerning the existence of truthful and individually rational mechanisms for purchasing private data from individuals with unbounded and sensitive privacy preferences. We strengthen the impossibility results of Ghosh and Roth (EC 2011) by extending it to a much wider class of privacy valuations. In particular, these include privacy valuations that are based on (ε δ)-differentially private mechanisms for non-zero δ, ones where the privacy costs are measured in a per-database manner (rather than taking the worst case), and ones that do not depend on the payments made to players (which might not be observable to an adversary). To bypass this impossibility result, we study a natural special setting where individuals have monotonic privacy valuations, which captures common contexts where certain values for private data are expected to lead to higher valuations for privacy (e. g. having a particular disease). We give new mechanisms that are individually rational for all players with monotonic privacy valuations, truthful for all players whose privacy valuations are not too large, and accurate if there are not too many players with too-large privacy valuations. We also prove matching lower bounds showing that in some respects our mechanism cannot be improved significantly.
{"title":"Redrawing the boundaries on purchasing data from privacy-sensitive individuals","authors":"Kobbi Nissim, S. Vadhan, David Xiao","doi":"10.1145/2554797.2554835","DOIUrl":"https://doi.org/10.1145/2554797.2554835","url":null,"abstract":"We prove new positive and negative results concerning the existence of truthful and individually rational mechanisms for purchasing private data from individuals with unbounded and sensitive privacy preferences. We strengthen the impossibility results of Ghosh and Roth (EC 2011) by extending it to a much wider class of privacy valuations. In particular, these include privacy valuations that are based on (ε δ)-differentially private mechanisms for non-zero δ, ones where the privacy costs are measured in a per-database manner (rather than taking the worst case), and ones that do not depend on the payments made to players (which might not be observable to an adversary). To bypass this impossibility result, we study a natural special setting where individuals have monotonic privacy valuations, which captures common contexts where certain values for private data are expected to lead to higher valuations for privacy (e. g. having a particular disease). We give new mechanisms that are individually rational for all players with monotonic privacy valuations, truthful for all players whose privacy valuations are not too large, and accurate if there are not too many players with too-large privacy valuations. We also prove matching lower bounds showing that in some respects our mechanism cannot be improved significantly.","PeriodicalId":382856,"journal":{"name":"Proceedings of the 5th conference on Innovations in theoretical computer science","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121749227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Quantum cryptography is based on the discovery that the laws of quantum mechanics allow levels of security that are impossible to replicate in a classical world [2, 8, 12]. Can such levels of security be guaranteed even when the quantum devices on which the protocol relies are untrusted? This fundamental question in quantum cryptography dates back to the early nineties when the challenge of achieving device independent quantum key distribution, or DIQKD, was first formulated [9]. We answer this challenge affirmatively by exhibiting a robust protocol for DIQKD and rigorously proving its security. The protocol achieves a linear key rate while tolerating a constant noise rate in the devices. The security proof assumes only that the devices can be modeled by the laws of quantum mechanics and are spatially isolated from each other and any adversary's laboratory. In particular, we emphasize that the devices may have quantum memory. All previous proofs of security relied either on the use of many independent pairs of devices [6, 4, 7], or on the absence of noise [10, 1]. To prove security for a DIQKD protocol it is necessary to establish at least that the generated key is truly random even in the presence of a quantum adversary. This is already a challenge, one that was recently resolved [14]. DIQKD is substantially harder, since now the protocol must also guarantee that the key is completely secret from the quantum adversary's point of view, and the entire protocol is robust against noise; this in spite of the substantial amounts of classical information leaked to the adversary throughout the protocol, as part of the error estimation and information reconciliation procedures. Our proof of security builds upon a number of techniques, including randomness extractors that are secure against quantum storage [3] as well as ideas originating in the coding strategy used in the proof of the Holevo-Schumacher-Westmoreland theorem [5, 11] which we apply to bound correlations across multiple rounds in a way not unrelated to information-theoretic proofs of the parallel repetition property for multiplayer games. Our main result can be understood as a new bound on monogamy [13] of entanglement in the type of complex scenario that arises in a key distribution protocol. Precise statements of our results and detailed proofs can be found at arXiv:1210.1810.
{"title":"Robust device independent quantum key distribution","authors":"U. Vazirani, Thomas Vidick","doi":"10.1145/2554797.2554802","DOIUrl":"https://doi.org/10.1145/2554797.2554802","url":null,"abstract":"Quantum cryptography is based on the discovery that the laws of quantum mechanics allow levels of security that are impossible to replicate in a classical world [2, 8, 12]. Can such levels of security be guaranteed even when the quantum devices on which the protocol relies are untrusted? This fundamental question in quantum cryptography dates back to the early nineties when the challenge of achieving device independent quantum key distribution, or DIQKD, was first formulated [9]. We answer this challenge affirmatively by exhibiting a robust protocol for DIQKD and rigorously proving its security. The protocol achieves a linear key rate while tolerating a constant noise rate in the devices. The security proof assumes only that the devices can be modeled by the laws of quantum mechanics and are spatially isolated from each other and any adversary's laboratory. In particular, we emphasize that the devices may have quantum memory. All previous proofs of security relied either on the use of many independent pairs of devices [6, 4, 7], or on the absence of noise [10, 1]. To prove security for a DIQKD protocol it is necessary to establish at least that the generated key is truly random even in the presence of a quantum adversary. This is already a challenge, one that was recently resolved [14]. DIQKD is substantially harder, since now the protocol must also guarantee that the key is completely secret from the quantum adversary's point of view, and the entire protocol is robust against noise; this in spite of the substantial amounts of classical information leaked to the adversary throughout the protocol, as part of the error estimation and information reconciliation procedures. Our proof of security builds upon a number of techniques, including randomness extractors that are secure against quantum storage [3] as well as ideas originating in the coding strategy used in the proof of the Holevo-Schumacher-Westmoreland theorem [5, 11] which we apply to bound correlations across multiple rounds in a way not unrelated to information-theoretic proofs of the parallel repetition property for multiplayer games. Our main result can be understood as a new bound on monogamy [13] of entanglement in the type of complex scenario that arises in a key distribution protocol. Precise statements of our results and detailed proofs can be found at arXiv:1210.1810.","PeriodicalId":382856,"journal":{"name":"Proceedings of the 5th conference on Innovations in theoretical computer science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129147041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Session details: Session 6: 10:30--10:40","authors":"V. Vaikuntanathan","doi":"10.1145/3255058","DOIUrl":"https://doi.org/10.1145/3255058","url":null,"abstract":"","PeriodicalId":382856,"journal":{"name":"Proceedings of the 5th conference on Innovations in theoretical computer science","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115896518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A random linear code has good minimal distance with high probability. The conjectured intractability of decoding random linear codes has recently found many applications in cryptography. One disadvantage of random linear codes is that their encoding complexity grows quadratically with the message length. Motivated by this disadvantage, we present a randomized construction of linear error-correcting codes which can be encoded in linear time and yet enjoy several useful features of random linear codes. Our construction is based on a linear-time computable hash function due to Ishai, Kushilevitz, Ostrovsky and Sahai [25]. We demonstrate the usefulness of these new codes by presenting several applications in coding theory and cryptography. These include the first family of linear-time encodable codes meeting the Gilbert-Varshamov bound, the first nontrivial linear-time secret sharing schemes, and plausible candidates for symmetric encryption and identification schemes which can be conjectured to achieve better asymptotic efficiency/security tradeoffs than all current candidates.
{"title":"Linear-time encodable codes meeting the gilbert-varshamov bound and their cryptographic applications","authors":"E. Druk, Y. Ishai","doi":"10.1145/2554797.2554815","DOIUrl":"https://doi.org/10.1145/2554797.2554815","url":null,"abstract":"A random linear code has good minimal distance with high probability. The conjectured intractability of decoding random linear codes has recently found many applications in cryptography. One disadvantage of random linear codes is that their encoding complexity grows quadratically with the message length. Motivated by this disadvantage, we present a randomized construction of linear error-correcting codes which can be encoded in linear time and yet enjoy several useful features of random linear codes. Our construction is based on a linear-time computable hash function due to Ishai, Kushilevitz, Ostrovsky and Sahai [25]. We demonstrate the usefulness of these new codes by presenting several applications in coding theory and cryptography. These include the first family of linear-time encodable codes meeting the Gilbert-Varshamov bound, the first nontrivial linear-time secret sharing schemes, and plausible candidates for symmetric encryption and identification schemes which can be conjectured to achieve better asymptotic efficiency/security tradeoffs than all current candidates.","PeriodicalId":382856,"journal":{"name":"Proceedings of the 5th conference on Innovations in theoretical computer science","volume":"9 11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127043977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Session details: Session 10: 10:30--10:40","authors":"Deeparnab Chakrabarty","doi":"10.1145/3255062","DOIUrl":"https://doi.org/10.1145/3255062","url":null,"abstract":"","PeriodicalId":382856,"journal":{"name":"Proceedings of the 5th conference on Innovations in theoretical computer science","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114547813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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