2019 IEEE 60th Annual Symposium on Foundations of Computer Science (FOCS)最新文献

{"title":"Polylogarithmic Guarantees for Generalized Reordering Buffer Management","authors":"Matthias Englert, Harald Räcke, Richard Stotz","doi":"10.1109/FOCS.2019.00012","DOIUrl":"https://doi.org/10.1109/FOCS.2019.00012","url":null,"abstract":"In the Generalized Reordering Buffer Management Problem (GRBM) a sequence of items located in a metric space arrives online, and has to be processed by a set of k servers moving within the space. In a single step the first b still unprocessed items from the sequence are accessible, and a scheduling strategy has to select an item and a server. Then the chosen item is processed by moving the chosen server to its location. The goal is to process all items while minimizing the total distance travelled by the servers. This problem was introduced in [Chan, Megow, Sitters, van Stee TCS 12] and has been subsequently studied in an online setting by [Azar, Englert, Gamzu, Kidron STACS 14]. The problem is a natural generalization of two very well-studied problems: the k-server problem for b=1 and the Reordering Buffer Management Problem (RBM) for k=1. In this paper we consider the GRBM problem on a uniform metric in the online version. We show how to obtain a competitive ratio of O(log k(log k+loglog b)) for this problem. Our result is a drastic improvement in the dependency on b compared to the previous best bound of O(√b log k), and is asymptotically optimal for constant k, because Ω(log k + loglog b) is a lower bound for GRBM on uniform metrics.","PeriodicalId":407139,"journal":{"name":"2019 IEEE 60th Annual Symposium on Foundations of Computer Science (FOCS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131277188","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":"Efficient Construction of Rigid Matrices Using an NP Oracle","authors":"Josh Alman, Lijie Chen","doi":"10.1109/FOCS.2019.00067","DOIUrl":"https://doi.org/10.1109/FOCS.2019.00067","url":null,"abstract":"For a matrix H over a field F, its rank-r rigidity, denoted R_H (r), is the minimum Hamming distance from H to a matrix of rank at most r over F. A central open challenge in complexity theory is to give explicit constructions of rigid matrices for a variety of parameter settings. In this work, building on Williams' seminal connection between circuit-analysis algorithms and lower bounds [Williams, J. ACM 2014], we give a construction of rigid matrices in P^NP. Letting q = p^r be a prime power, we show: • There is an absolute constant δ>0 such that, for all constants ε >0, there is a P^NP machine M such that, for infinitely many N's, M(1^N) outputs a matrix H_N ∊ {0,1}^N×N with R_H_N (2^ (log N)^ 1/4-ε) ≥ δ ⋅ N^2 over F_q. Using known connections between matrix rigidity and other topics in complexity theory, we derive several consequences of our constructions, including: • There is a function f ∊ TIME [2^ (log n)^ ω(1)]^ NP such that f ∉ PH^cc. Previously, it was open whether E^NP ⊂ PH^cc. • For all ε >0, there is a P^NP machine M such that, for infinitely many N's, M(1^N) outputs an N × N matrix H_N ∊ {0,1}^N×N whose linear transformation requires depth-2 F_q-linear circuits of size Ω(N ⋅ 2^ (log N)^ 1/4 - ε). The previous best lower bound for an explicit family of N × N matrices over F_q was only Ω(N log^2 N / (log log N)^2), for asymptotically good error-correcting codes.","PeriodicalId":407139,"journal":{"name":"2019 IEEE 60th Annual Symposium on Foundations of Computer Science (FOCS)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128303488","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":"Sampling Graphs without Forbidden Subgraphs and Unbalanced Expanders with Negligible Error","authors":"B. Applebaum, Eliran Kachlon","doi":"10.1109/FOCS.2019.00020","DOIUrl":"https://doi.org/10.1109/FOCS.2019.00020","url":null,"abstract":"Suppose that you wish to sample a random graph G over n vertices and m edges conditioned on the event that G does not contain a “small\" t-size graph H (e.g., clique) as a subgraph. Assuming that most such graphs are H-free, the problem can be solved by a simple rejected-sampling algorithm (that tests for t-cliques) with an expected running time of n^O(t). Is it possible to solve the problem in running time that does not grow polynomially with n^t? In this paper, we introduce the general problem of sampling a “random looking'' graph G with a given edge density that avoids some arbitrary predefined t-size subgraph H. As our main result, we show that the problem is solvable with respect to some specially crafted k-wise independent distribution over graphs. That is, we design a sampling algorithm for k-wise independent graphs that supports efficient testing for subgraph-freeness in time f(t)⋅ n^c where f is a function of t and the constant c in the exponent is independent of t. Our solution extends to the case where both G and H are d-uniform hypergraphs. We use these algorithms to obtain the first probabilistic construction of constant-degree polynomially-unbalanced expander graphs whose failure probability is negligible in n (i.e., n^-ω(1)). In particular, given constants d>c, we output a bipartite graph that has n left nodes, n^c right nodes with right-degree of d so that any right set of size at most n^Ω(1) expands by factor of Ω(d). This result is extended to the setting of unique expansion as well. We observe that such a negligible-error construction can be employed in many useful settings, and present applications in coding theory (batch codes and LDPC codes), pseudorandomness (low-bias generators and randomness extractors) and cryptography. Notably, we show that our constructions yield a collection of polynomial-stretch locally-computable cryptographic pseudorandom generators based on Goldreich's one-wayness assumption resolving a central open problem in parallel-cryptography (cf., Applebaum-Ishai-Kushilevitz, FOCS 2004; and Ishai-Kushilevitz-Ostrovsky-Sahai, STOC 2008).","PeriodicalId":407139,"journal":{"name":"2019 IEEE 60th Annual Symposium on Foundations of Computer Science (FOCS)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134221609","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":"Quasilinear Time List-Decodable Codes for Space Bounded Channels","authors":"Ronen Shaltiel, Swastik Kopparty, Jad Silbak","doi":"10.1109/FOCS.2019.00028","DOIUrl":"https://doi.org/10.1109/FOCS.2019.00028","url":null,"abstract":"We consider codes for space bounded channels. This is a model for communication under noise that was studied by Guruswami and Smith (J. ACM 2016) and lies between the Shannon (random) and Hamming (adversarial) models. In this model, a channel is a space bounded procedure that reads the codeword in one pass, and modifies at most a p fraction of the bits of the codeword. Guruswami and Smith, and later work by Shaltiel and Silbak (RANDOM 2016), gave constructions of list-decodable codes with rate approaching 1-H(p) against channels with space s=c log n, with encoding/decoding time poly(2^s)= poly(n^c). In this paper we show that for every constant 0 ≤ p < ½, and every sufficiently small constant ε>0, there are codes with rate R ≥ 1-H(p)-ε, list size poly(1/ε), and furthermore: • Our codes can handle channels with space s=n^Ω(1), which is much larger than O(log n) achieved by previous work. • We give encoding and decoding algorithms that run in time n polylog(n). Previous work achieved large and unspecified poly(n) time (even for space s=1 ⋅ log n channels). • We can handle space bounded channels that read the codeword in any order, whereas previous work considered channels that read the codeword in the standard order. Our construction builds on the machinery of Guruswami and Smith (with some key modifications) replacing some nonconstructive codes and pseudorandom objects (that are found in exponential time by brute force) with efficient explicit constructions. For this purpose we exploit recent results of Haramaty, Lee and Viola (SICOMP 2018) on pseudorandom properties of “t-wise independence + low weight noise'' which we quantitatively improve using techniques by Forbes and Kelly (FOCS 2018). To make use of such distributions, we give new explicit constructions of binary linear codes that have dual distance of n^Ω(1), and are also polynomial time list-decodable from relative distance ½ -ε, with list size poly(1/ε). To the best of our knowledge, no such construction was previously known. Somewhat surprisingly, we show that Reed-Solomon codes with dimension k<√n, have this property if interpreted as binary codes (in some specific interpretation) which we term: “Raw Reed-Solomon Codes''. A key idea is viewing Reed-Solomon codes as “bundles'' of certain dual-BCH codewords.","PeriodicalId":407139,"journal":{"name":"2019 IEEE 60th Annual Symposium on Foundations of Computer Science (FOCS)","volume":"2015 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114522992","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":"Residual Based Sampling for Online Low Rank Approximation","authors":"Aditya Bhaskara, Silvio Lattanzi, Sergei Vassilvitskii, Morteza Zadimoghaddam","doi":"10.1109/FOCS.2019.00094","DOIUrl":"https://doi.org/10.1109/FOCS.2019.00094","url":null,"abstract":"We propose online algorithms for Column Subset Selection (CSS) and Principal Component Analysis (PCA), two methods that are widely employed for data analysis, summarization, and visualization. Given a data matrix A that is revealed one column at a time, the online CSS problems asks to keep a small set of columns, S, that best approximates the space spanned by the columns of A. As each column arrives, the algorithm must irrevocably decide whether to add it to S, or to ignore it. In the online PCA problem, the goal is to output a projection of each column to a low dimensional subspace. In other words, the algorithm must provide an embedding for each column as it arrives, which cannot be changed as new columns arrive. While both of these problems have been studied in the online setting, only additive approximations were known prior to our work. The core of our approach is an adaptive sampling technique that gives a practical and efficient algorithm for both of these problems. We prove that by sampling columns using their 'residual norm'' (i.e. their norm orthogonal to directions sampled so far), we end up with a significantly better dependence between the number of columns sampled, and the desired error in the approximation. We further show how to combine our algorithm \"in series'' with prior algorithms. In particular, using the results of Boutsidis et al. and Frieze et al. that have additive guarantees, we show how to improve the bounds on the error of our algorithm.","PeriodicalId":407139,"journal":{"name":"2019 IEEE 60th Annual Symposium on Foundations of Computer Science (FOCS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124166424","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":"NEEXP is Contained in MIP*","authors":"Anand Natarajan, John Wright","doi":"10.1109/FOCS.2019.00039","DOIUrl":"https://doi.org/10.1109/FOCS.2019.00039","url":null,"abstract":"We study multiprover interactive proof systems. The power of classical multiprover interactive proof systems, in which the provers do not share entanglement, was characterized in a famous work by Babai, Fortnow, and Lund (Computational Complexity 1991), whose main result was the equality MIP = NEXP. The power of quantum multiprover interactive proof systems, in which the provers are allowed to share entanglement, has proven to be much more difficult to characterize. The best known lower-bound on MIP* is NEXP, due to Ito and Vidick (FOCS 2012). As for upper bounds, MIP* could be as large as RE, the class of recursively enumerable languages. The main result of this work is the inclusion of NEEXP (nondeterministic doubly exponential time) in MIP*. This is an exponential improvement over the prior lower bound and shows that proof systems with entangled provers are at least exponentially more powerful than classical provers. In our protocol the verifier delegates a classical, exponentially large MIP protocol for NEEXP to two entangled provers: the provers obtain their exponentially large questions by measuring their shared state, and use a classical PCP to certify the correctness of their exponentially-long answers. For the soundness of our protocol, it is crucial that each player should not only sample its own question correctly but also avoid performing measurements that would reveal the other player's sampled question. We ensure this by commanding the players to perform a complementary measurement, relying on the Heisenberg uncertainty principle to prevent the forbidden measurements from being performed.","PeriodicalId":407139,"journal":{"name":"2019 IEEE 60th Annual Symposium on Foundations of Computer Science (FOCS)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123520635","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":"Non-Malleable Commitments using Goldreich-Levin List Decoding","authors":"Vipul Goyal, Silas Richelson","doi":"10.1109/FOCS.2019.00047","DOIUrl":"https://doi.org/10.1109/FOCS.2019.00047","url":null,"abstract":"We give the first construction of three-round non-malleable commitments from the almost minimal assumption of injective one-way functions. Combined with the lower bound of Pass (TCC 2013), our result is almost the best possible w.r.t. standard polynomial-time hardness assumptions (at least w.r.t. black-box reductions). Our results rely on a novel technique which we call 'bidirectional Goldreich-Levin extraction'. Along the way, we also obtain the first rewind secure delayed-input witness indistinguishable (WI) proofs from only injective one-way functions. We also obtain the first construction of an epsilon-extractable commitment scheme from injective one-way functions. We believe both of these to be of independent interest. In particular, as a direct corollary of our rewind secure WI construction, we are able to obtain a construction of 3-round promise zero-knowledge from only injective one-way functions.","PeriodicalId":407139,"journal":{"name":"2019 IEEE 60th Annual Symposium on Foundations of Computer Science (FOCS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130212504","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":"Hardness Magnification for all Sparse NP Languages","authors":"Lijie Chen, Ce Jin, Ryan Williams","doi":"10.1109/FOCS.2019.00077","DOIUrl":"https://doi.org/10.1109/FOCS.2019.00077","url":null,"abstract":"In the Minimum Circuit Size Problem (MCSP[s(m)]), we ask if there is a circuit of size s(m) computing a given truth-table of length n = 2^m. Recently, a surprising phenomenon termed as hardness magnification by [Oliveira and Santhanam, FOCS 2018] was discovered for MCSP[s(m)] and the related problem MKtP of computing time-bounded Kolmogorov complexity. In [Oliveira and Santhanam, FOCS 2018], [Oliveira, Pich, and Santhanam, CCC 2019], and [McKay, Murray, and Williams, STOC 2019], it was shown that minor (n^{1+eps}-style) lower bounds for MCSP[2^o(m)] or MKtP[2^o(m)] would imply breakthrough circuit lower bounds such as NP is not in P/poly, NP is not in NC^1, or EXP is not in P/poly. We consider the question: What is so special about MCSP and MKtP? Why do they admit this striking phenomenon? One simple property is that all variants of MCSP (and MKtP) considered in prior work are sparse languages. For example, MCSP[s(m)] has 2^{O(s(m))} yes-instances of length n=2^m, so MCSP[2^o(m)] is 2^{n^o(1)}-sparse. We show that there is a hardness magnification phenomenon for all equally-sparse NP languages. Formally, suppose there is an eps > 0 and a language L in NP which is 2^{n^o(1)}-sparse, and L is not in Circuit[n^{1+eps}]. Then NP does not have n^k-size circuits for all k. We prove analogous theorems for De Morgan formulas, B_2-formulas, branching programs, AC^0[6] and TC^0 circuits, and more: improving the state of the art in NP lower bounds against any of these models by an eps factor in the exponent would already imply NP lower bounds for all fixed polynomials. In fact, in our proofs it is not necessary to prove a (say) n^{1+eps} circuit size lower bound for L: one only has to prove a lower bound against n^{1+eps}-time n^eps-space deterministic algorithms with n^eps advice bits. Such lower bounds are well-known for non-sparse problems. Building on our techniques, we also show interesting new hardness magnifications for search-MCSP and search-MKtP (where one must output small circuits or short representations of strings), showing consequences such as Parity-P (or PP, PSPACE, and EXP) is not contained in P/poly (or NC^1, AC^0[6], or branching programs of polynomial size). For instance, if there is an eps > 0 such that search-MCSP[2^{beta m}] does not have De Morgan formulas of size n^{3+eps} for all constants beta > 0, then ⊕-P ⊄ NC^1.","PeriodicalId":407139,"journal":{"name":"2019 IEEE 60th Annual Symposium on Foundations of Computer Science (FOCS)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116910500","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":"Towards a Theory of Non-Commutative Optimization: Geodesic 1st and 2nd Order Methods for Moment Maps and Polytopes","authors":"Peter Bürgisser, Cole Franks, A. Garg, R. Oliveira, M. Walter, A. Wigderson","doi":"10.1109/FOCS.2019.00055","DOIUrl":"https://doi.org/10.1109/FOCS.2019.00055","url":null,"abstract":"This paper initiates a systematic development of a theory of non-commutative optimization, a setting which greatly extends ordinary (Euclidean) convex optimization. It aims to unify and generalize a growing body of work from the past few years which developed and analyzed algorithms for natural geodesic convex optimization problems on Riemannian manifolds that arise from the symmetries of non-commutative groups. More specifically, these are algorithms to minimize the moment map (a non-commutative notion of the usual gradient), and to test membership in moment polytopes (a vast class of polytopes, typically of exponential vertex and facet complexity, which quite magically arise from this a-priori non-convex, non-linear setting). The importance of understanding this very general setting of geodesic optimization, as these works unveiled and powerfully demonstrate, is that it captures a diverse set of problems, many non-convex, in different areas of CS, math, and physics. Several of them were solved efficiently for the first time using non-commutative methods; the corresponding algorithms also lead to solutions of purely structural problems and to many new connections between disparate fields. In the spirit of standard convex optimization, we develop two general methods in the geodesic setting, a first order and a second order method, which respectively receive first and second order information on the \"derivatives\" of the function to be optimized. These in particular subsume all past results. The main technical work, again unifying and extending much of the previous work, goes into identifying the key parameters of the underlying group actions which control convergence to the optimum in each of these methods. These non-commutative analogues of \"smoothness\" in the commutative case are far more complex, and require significant algebraic and analytic machinery (much existing and some newly developed here). Despite this complexity, the way in which these parameters control convergence in both methods is quite simple and elegant. We also bound these parameters in several general cases. Our work points to intriguing open problems and suggests further research directions. We believe that extending this theory, namely understanding geodesic optimization better, is both mathematically and computationally fascinating; it provides a great meeting place for ideas and techniques from several very different research areas, and promises better algorithms for existing and yet unforeseen applications.","PeriodicalId":407139,"journal":{"name":"2019 IEEE 60th Annual Symposium on Foundations of Computer Science (FOCS)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124005727","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":"Near-Optimal Massively Parallel Graph Connectivity","authors":"Soheil Behnezhad, Laxman Dhulipala, Hossein Esfandiari, Jakub Lacki, V. Mirrokni","doi":"10.1109/FOCS.2019.00095","DOIUrl":"https://doi.org/10.1109/FOCS.2019.00095","url":null,"abstract":"Identifying the connected components of a graph, apart from being a fundamental problem with countless applications, is a key primitive for many other algorithms. In this paper, we consider this problem in parallel settings. Particularly, we focus on the Massively Parallel Computations (MPC) model, which is the standard theoretical model for modern parallel frameworks such as MapReduce, Hadoop, or Spark. We consider the truly sublinear regime of MPC for graph problems where the space per machine is n^δ for some desirably small constant δ ∊ (0, 1). We present an algorithm that for graphs with diameter D in the wide range [log^ε n, n], takes O(log D) rounds to identify the connected components and takes O(log log n) rounds for all other graphs. The algorithm is randomized, succeeds with high probability, does not require prior knowledge of D, and uses an optimal total space of O(m). We complement this by showing a conditional lower-bound based on the widely believed TwoCycle conjecture that Ω(log D) rounds are indeed necessary in this setting. Studying parallel connectivity algorithms received a resurgence of interest after the pioneering work of Andoni etal [FOCS 2018] who presented an algorithm with O(log D log log n) round-complexity. Our algorithm improves this result for the whole range of values of D and almost settles the problem due to the conditional lower-bound. Additionally, we show that with minimal adjustments, our algorithm can also be implemented in a variant of (CRCW) PRAM in asymptotically the same number of rounds.","PeriodicalId":407139,"journal":{"name":"2019 IEEE 60th Annual Symposium on Foundations of Computer Science (FOCS)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126445364","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}