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OpenFst: A general and efficient weighted finitestate transducer library. Implementation and Application of Automata
, 2007
"... Abstract. We describe OpenFst, an opensource library for weighted finitestate transducers (WFSTs). OpenFst consists of a C++ template library with efficient WFST representations and over twentyfive operations for constructing, combining, optimizing, and searching them. At the shellcommand level, ..."
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Cited by 74 (9 self)
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Abstract. We describe OpenFst, an opensource library for weighted finitestate transducers (WFSTs). OpenFst consists of a C++ template library with efficient WFST representations and over twentyfive operations for constructing, combining, optimizing, and searching them. At the shellcommand level, there are corresponding transducer file representations and programs that operate on them. OpenFst is designed to be both very efficient in time and space and to scale to very large problems. This library has key applications speech, image, and natural language processing, pattern and string matching, and machine learning. We give an overview of the library, examples of its use, details of its design that allow customizing the labels, states, and weights and the lazy evaluation of many of its operations. Further information and a download of the OpenFst library can be obtained from
Theory and Algorithms for Modern Problems in Machine Learning and an Analysis of Markets
, 2008
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A Probabilistic Kleene Theorem
"... We provide a Kleene Theorem for (Rabin) probabilistic automata over finite words. Probabilistic automata generalize deterministic finite automata and assign to a word an acceptance probability. We provide probabilistic expressions with probabilistic choice, guarded choice, concatenation, and a sta ..."
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We provide a Kleene Theorem for (Rabin) probabilistic automata over finite words. Probabilistic automata generalize deterministic finite automata and assign to a word an acceptance probability. We provide probabilistic expressions with probabilistic choice, guarded choice, concatenation, and a star operator. We prove that probabilistic expressions and probabilistic automata are expressively equivalent. Our result actually extends to twoway probabilistic automata with pebbles and corresponding expressions.
International Journal of Foundations of Computer Science c ○ World Scientific Publishing Company General Algorithms for Testing the Ambiguity of Finite Automata and the DoubleTape Ambiguity of FiniteState Transducers
"... We present efficient algorithms for testing the finite, polynomial, and exponential ambiguity of finite automata with ǫtransitions. We give an algorithm for testing the exponential ambiguity of an automaton A in time O(A  2 E), and finite or polynomial ambiguity in time O(A  3 E), where AE de ..."
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We present efficient algorithms for testing the finite, polynomial, and exponential ambiguity of finite automata with ǫtransitions. We give an algorithm for testing the exponential ambiguity of an automaton A in time O(A  2 E), and finite or polynomial ambiguity in time O(A  3 E), where AE denotes the number of transitions of A. These complexities significantly improve over the previous best complexities given for the same problem. Furthermore, the algorithms presented are simple and based on a general algorithm for the composition or intersection of automata. Additionally, we give an algorithm to determine in time O(A  3 E) the degree of polynomial ambiguity of a polynomially ambiguous automaton A and present an application of our algorithms to an approximate computation of the entropy of a probabilistic automaton. We also study the doubletape ambiguity of finitestate transducers. We show that the general problem is undecidable and that it is NPhard for acyclic transducers. We present a specific analysis of the doubletape ambiguity of transducers with bounded delay. In particular, we give a characterization of doubletape ambiguity for synchronized transducers with zero delay that can be tested in quadratic time and give an algorithm for testing the doubletape ambiguity of transducers with bounded delay.
International Journal of Foundations of Computer Science c ○ World Scientific Publishing Company Lp Distance and Equivalence of Probabilistic Automata
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Beyond Differential Privacy: Composition Theorems and Relational Logic for fdivergences between Probabilistic Programs
"... Abstract. fdivergences form a class of measures of distance between probability distributions; they are widely used in areas such as information theory and signal processing. In this paper, we unveil a new connection between fdivergences and differential privacy, a confidentiality policy that prov ..."
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Abstract. fdivergences form a class of measures of distance between probability distributions; they are widely used in areas such as information theory and signal processing. In this paper, we unveil a new connection between fdivergences and differential privacy, a confidentiality policy that provides strong privacy guarantees for private datamining; specifically, we observe that the notion of αdistance used to characterize approximate differential privacy is an instance of the family offdivergences. Building on this observation, we generalize to arbitrary fdivergences the sequential composition theorem of differential privacy. Then, we propose a relational program logic to prove upper bounds for the fdivergence between two probabilistic programs. Our results allow us to revisit the foundations of differential privacy under a new light, and to pave the way for applications that use different instances of fdivergences. 1