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‣ Corpus-based unit selection for natural-sounding speech synthesis

Yi, Jon Rong-Wei, 1975-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 214 p.; 3462128 bytes; 3461885 bytes; application/pdf; application/pdf
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Speech synthesis is an automatic encoding process carried out by machine through which symbols conveying linguistic information are converted into an acoustic waveform. In the past decade or so, a recent trend toward a non-parametric, corpus-based approach has focused on using real human speech as source material for producing novel natural-sounding speech. This work proposes a communication-theoretic formulation in which unit selection is a noisy channel through which an input sequence of symbols passes and an output sequence, possibly corrupted due to the coverage limits of the corpus, emerges. The penalty of approximation is quantified by substitution and concatenation costs which grade what unit contexts are interchangeable and where concatenations are not perceivable. These costs are semi-automatically derived from data and are found to agree with acoustic-phonetic knowledge. The implementation is based on a finite-state transducer (FST) representation that has been successfully used in speech and language processing applications including speech recognition. A proposed constraint kernel topology connects all units in the corpus with associated substitution and concatenation costs and enables an efficient Viterbi search that operates with low latency and scales to large corpora. An A* search can be applied in a second...

‣ Analysis and specification of office procedures

Kunin, Jay Stuart
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 232 leaves; 18798434 bytes; 18798193 bytes; application/pdf; application/pdf
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by Jay Stuart Kunin.; Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Bibliography: leaves 228-232.

‣ Efficient implementation of applicative languages

Ackerman, William Beekley
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 199 leaves; 10046966 bytes; 10046724 bytes; application/pdf; application/pdf
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by William Beekley Ackerman.; Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1984.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Bibliography: leaves 196-199.

‣ Optimal interpreters for lambda-calculus based functional languages

Kathail, Vinod
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 197 leaves; 14714672 bytes; 14714431 bytes; application/pdf; application/pdf
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by Vinod Kumar Kathail.; Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1990.; Includes bibliographical references (leaves 195-197).

‣ On the power of nondeterminism in small two-way finite automata; On the power of nondeterminism in small 2DFA

Kapoutsis, Christos, 1974-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 26 p.; 1416389 bytes; 1416574 bytes; application/pdf; application/pdf
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We examine the conjecture that one-way nondeterministic finite automata (NFAS) can be exponentially more succinct than two-way deterministic ones (2DFAS); equivalently, that no polynomial-size sequence of 2DFAs can recognize B, for B a particular sequence of regular languages that is among the hardest of those recognizable by polynomial-size sequences of 1NFAs. We prove that the most natural single-pass 2DFA algorithm for deciding B fails, "single-pass" meaning that the automaton is bound to terminate as soon as it reaches an endmarker for the first time. On the way, we introduce the notion of dilemmas as an interesting general tool for constructing hard inputs for 2DFAS.; by Christos Kapoutsis.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.; Includes bibliographical references (p. 25-26).

‣ Event structure and the encoding of arguments : the syntax of the Mandarin and English verb phrase

Lin, Jimmy J. (Jimmy Jr-Pin), 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 194 p.; 9880232 bytes; 9905049 bytes; application/pdf; application/pdf
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(cont.) to variations in the way functional elements interact with verbal roots. Overall, my work not only contributes to our understanding of how events are syntactically represented, but also explicates interactions at the syntax-semantics interface, clarifying the relationship between surface form, syntactic structure, and logical form. A theory of argument structure grounded in independently-motivated syntactic constraints, on the one hand, and the semantic structure of events, on the other hand, is able to account for a wide range of empirical facts with few stipulations.; This work presents a theory of linguistic representation that attempts to capture the syntactic structure of verbs and their arguments. My framework is based on the assumption that the proper representation of argument structure is event structure. Furthermore, I develop the hypothesis that event structure is syntactic structure, and argue that verb meanings are compositionally derived in the syntax from verbalizing heads, functional elements that license eventive interpretations, and verbal roots, abstract concepts drawn from encyclopedic knowledge. The overall goal of the enterprise is to develop a theory that is able to transparently relate the structure and meaning of verbal arguments. By hypothesis...

‣ A scalable mixed-level approach to dynamic analysis of C and C++ programs

Guo, Philip Jia
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 112 p.
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This thesis addresses the difficult task of constructing robust and scalable dynamic program analysis tools for programs written in memory-unsafe languages such as C and C++, especially those that are interested in observing the contents of data structures at run time. In this thesis, I first introduce my novel mixed-level approach to dynamic analysis, which combines the advantages of both source- and binary-based approaches. Second, I present a tool framework that embodies the mixed-level approach. This framework provides memory safety guarantees, allows tools built upon it to access rich source- and binary-level information simultaneously at run time, and enables tools to scale to large, real-world C and C++ programs on the order of millions of lines of code. Third, I present two dynamic analysis tools built upon my framework - one for performing value profiling and the other for performing dynamic inference of abstract types - and describe how they far surpass previous analyses in terms of scalability, robustness, and applicability. Lastly, I present several case studies demonstrating how these tools aid both humans and automated tools in several program analysis tasks: improving human understanding of unfamiliar code, invariant detection...

‣ Silicon Compilation of Very High Level Languages

Kahrs, Mark W. ; Allen, James F.
Fonte: University of Rochester. Computer Science Department. Publicador: University of Rochester. Computer Science Department.
Tipo: Thesis; Technical Report
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Thesis (Ph. D.)--University of Rochester. Dept. of Computer Science, 1984. Simultaneously published in the Technical Report series.; The report concerns the design and implementation of a compiler for two Very High Level Languages. The first language is a set language similar to VERS or SETL. The second language is a novel signal processing language. The compiler uses data flow and type information to constrain possible choices before choosing a possible implementation. Heuristic search is then used to choose from competing implementations of abstract data types. Constraint propagation is used at every selection step to remove incompatible configurations from the search. Finally, the use of specialized procedures called "design critics" is proposed to resolve global constraint conflicts. The output of the compiler is a parts list, a net list of module interconnections and the fields of the control store.

‣ SUDS : automatic parallelization for raw processors

Frank, Matthew I
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 181 p.; 11002412 bytes; 11025390 bytes; application/pdf; application/pdf
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A computer can never be too fast or too cheap. Computer systems pervade nearly every aspect of science, engineering, communications and commerce because they perform certain tasks at rates unachievable by any other kind of system built by humans. A computer system's throughput, however, is constrained by that system's ability to find concurrency. Given a particular target work load the computer architect's role is to design mechanisms to find and exploit the available concurrency in that work load. This thesis describes SUDS (Software Un-Do System), a compiler and runtime system that can automatically find and exploit the available concurrency of scalar operations in imperative programs with arbitrary unstructured and unpredictable control flow. The core compiler transformation that enables this is scalar queue conversion. Scalar queue conversion makes scalar renaming an explicit operation through a process similar to closure conversion, a technique traditionally used to compile functional languages. The scalar queue conversion compiler transformation is speculative, in the sense that it may introduce dynamic memory allocation operations into code that would not otherwise dynamically allocate memory. Thus, SUDS also includes a transactional runtime system that periodically checkpoints machine state...

‣ Starkiller : a static type inferencer and compiler for Python; Static type inferencer for dynamic languages

Salib, Michael, 1978-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 96 leaves; 436696 bytes; 435331 bytes; application/pdf; application/pdf
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Starkiller is a type inferencer and compiler for the dynamic language Python designed to generate fast native code. It analyzes Python source programs and converts them into equivalent C++ programs. Starkiller's type inference algorithm is based on the Cartesian Product Algorithm but has been significantly modified to support a radically different language. It includes an External Type Description Language that enables extension authors to document how their foreign code extensions interact with Python. This enables Starkiller to analyze Python code that interacts with foreign code written in C, C++, or Fortran. The type inference algorithm also handles data polymorphism in addition to parametric polymorphism, thus improving precision. Starkiller supports the entire Python language except for dynamic code insertion features such as eval and dynamic module loading. While the system is not yet complete, early numeric benchmarks show that Starkiller compiled code performs almost as well as hand made C code and substantially better than alternative Python compilers.; by Michael Salib.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.; Includes bibliographical references (leaves 93-96).; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.

‣ Log-space counter is useful for unary languages by help of a constant-size quantum register

Yakaryilmaz, Abuzer
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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The minimum amount of resources to recognize a nonregular language is a fundamental research topic in theoretical computer science which has been examined for different kinds of resources and many different models. In this note, we focus on unary languages and space complexity on counters. Our model is two-way one-counter automaton with quantum and classical states (2QCCA), which is a two-way finite automaton with one-counter (2DCA) augmented with a fixed size quantum register or a two-way finite automaton with quantum and classical states (2QCFA) augmented with a classical counter. It is known that any 2DCA using a sublinear space on its counter can recognize only regular languages \cite{DG82B}. In this note, we show that bounded-error 2QCCAs can recognize a non-regular unary language by using logarithmic space on its counters for the members. Note that it is still an open problem whether bounded-error 2QCFA can recognize a non-regular unary language.; Comment: The text is updated by adding a new reference. Technical report. 10 pages. arXiv admin note: text overlap with arXiv:1207.3880

‣ Deterministic pushdown automata and unary languages

Pighizzini, Giovanni
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 08/05/2009 Português
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The simulation of deterministic pushdown automata defined over a one-letter alphabet by finite state automata is investigated from a descriptional complexity point of view. We show that each unary deterministic pushdown automaton of size s can be simulated by a deterministic finite automaton with a number of states that is exponential in s. We prove that this simulation is tight. Furthermore, its cost cannot be reduced even if it is performed by a two-way nondeterministic automaton. We also prove that there are unary languages for which deterministic pushdown automata cannot be exponentially more succinct than finite automata. In order to state this result, we investigate the conversion of deterministic pushdown automata into context-free grammars. We prove that in the unary case the number of variables in the resulting grammar is strictly smaller than the number of variables needed in the case of nonunary alphabets.; Comment: 17 pages. Preprint of an article submitted for consideration in the International Journal of Foundations of Computer Science (World Scientific Publishing Company). A preliminary version was presented at the conference CIAA 2008

‣ Precedence Automata and Languages

Lonati, Violetta; Mandrioli, Dino; Pradella, Matteo
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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Operator precedence grammars define a classical Boolean and deterministic context-free family (called Floyd languages or FLs). FLs have been shown to strictly include the well-known visibly pushdown languages, and enjoy the same nice closure properties. We introduce here Floyd automata, an equivalent operational formalism for defining FLs. This also permits to extend the class to deal with infinite strings to perform for instance model checking.; Comment: Extended version of the paper which appeared in Proceedings of CSR 2011, Lecture Notes in Computer Science, vol. 6651, pp. 291-304, 2011. Theorem 1 has been corrected and a complete proof is given in Appendix

‣ Proceedings 14th International Conference on Automata and Formal Languages

Ésik, Zoltán; Fülöp, Zoltán
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 20/05/2014 Português
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The 14th International Conference Automata and Formal Languages (AFL 2014) was held in Szeged, Hungary, from the 27th to the 29th of May, 2014. The conference was organized by the Department of Foundations of Computer Science of the University of Szeged. Topics of interest covered the theory and applications of automata and formal languages and related areas.

‣ Pseudorandom Generators Against Advised Context-Free Languages

Yamakami, Tomoyuki
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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Pseudorandomness has played a central role in modern cryptography, finding theoretical and practical applications to various fields of computer science. A function that generates pseudorandom strings from shorter but truly random seeds is known as a pseudorandom generator. Our generators are designed to fool languages (or equivalently, Boolean-valued functions). In particular, our generator fools advised context-free languages, namely, context-free languages assisted by external information known as advice, and moreover our generator is made almost one-to-one, stretching $n$-bit seeds to $n+1$ bits. We explicitly construct such a pseudorandom generator, which is computed by a deterministic Turing machine using logarithmic space and also belongs to CFLMV(2)/n---a functional extension of the 2-conjunctive closure of CFL with the help of appropriate deterministic advice. In contrast, we show that there is no almost one-to-one pseudorandom generator against context-free languages if we demand that it should be computed by a nondeterministic pushdown automaton equipped with a write-only output tape. Our generator naturally extends known pseudorandom generators against advised regular languages. Our proof of the CFL/n-pseudorandomness of the generator is quite elementary...

‣ On Pebble Automata for Data Languages with Decidable Emptiness Problem

Tan, Tony
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/10/2009 Português
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In this paper we study a subclass of pebble automata (PA) for data languages for which the emptiness problem is decidable. Namely, we introduce the so-called top view weak PA. Roughly speaking, top view weak PA are weak PA where the equality test is performed only between the data values seen by the two most recently placed pebbles. The emptiness problem for this model is decidable. We also show that it is robust: alternating, nondeterministic and deterministic top view weak PA have the same recognition power. Moreover, this model is strong enough to accept all data languages expressible in Linear Temporal Logic with the future-time operators, augmented with one register freeze quantifier.; Comment: An extended abstract of this work has been published in the proceedings of the 34th International Symposium on Mathematical Foundations of Computer Science (MFCS) 2009}, Springer, Lecture Notes in Computer Science 5734, pages 712-723

‣ Oracle Pushdown Automata, Nondeterministic Reducibilities, and the CFL Hierarchy over the Family of Context-Free Languages

Yamakami, Tomoyuki
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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To expand a fundamental theory of context-free languages, we equip nondeterministic one-way pushdown automata with additional oracle mechanisms, which naturally induce various nondeterministic reducibilities among formal languages. As a natural restriction of NP-reducibility, we introduce a notion of many-one CFL reducibility and conduct a ground work to formulate a coherent framework for further expositions. Two more powerful reducibilities--bounded truth-table and Turing CFL-reducibilities--are also discussed in comparison. The Turing CFL-reducibility, in particular, helps us introduce an exquisite hierarchy, called the CFL hierarchy, built over the family CFL of context-free languages. For each level of this hierarchy, its basic structural properties are proven and three alternative characterizations are presented. The second level is not included in NC(2) unless NP= NC(2). The first and second levels of the hierarchy are different. The rest of the hierarchy (more strongly, the Boolean hierarchy built over each level of the hierarchy) is also infinite unless the polynomial hierarchy over NP collapses. This follows from a characterization of the Boolean hierarchy over the k-th level of the polynomial hierarchy in terms of the Boolean hierarchy over the k+1st level of the CFL hierarchy using log-space many-one reductions. Similarly...

‣ The separation problem for regular languages by piecewise testable languages

van Rooijen, Lorijn; Zeitoun, Marc
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 08/03/2013 Português
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Separation is a classical problem in mathematics and computer science. It asks whether, given two sets belonging to some class, it is possible to separate them by another set of a smaller class. We present and discuss the separation problem for regular languages. We then give a direct polynomial time algorithm to check whether two given regular languages are separable by a piecewise testable language, that is, whether a $B{\Sigma}1(<)$ sentence can witness that the languages are indeed disjoint. The proof is a reformulation and a refinement of an algebraic argument already given by Almeida and the second author.

‣ Tarski's influence on computer science

Feferman, Solomon
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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The influence of Alfred Tarski on computer science was indirect but significant in a number of directions and was in certain respects fundamental. Here surveyed is the work of Tarski on the decision procedure for algebra and geometry, the method of elimination of quantifiers, the semantics of formal languages, modeltheoretic preservation theorems, and algebraic logic; various connections of each with computer science are taken up.

‣ Entropy sensitivity of languages defined by infinite automata, via Markov chains with forbidden transitions

Huss, Wilfried; Sava, Ecaterina; Woess, Wolfgang
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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A language L over a finite alphabet is growth-sensitive (or entropy sensitive) if forbidding any set of subwords F yields a sub-language L^F whose exponential growth rate (entropy) is smaller than that of L. Let (X, E, l) be an infinite, oriented, labelled graph. Considering the graph as an (infinite) automaton, we associate with any pair of vertices x,y in X the language consisting of all words that can be read as the labels along some path from x to y. Under suitable, general assumptions we prove that these languages are growth-sensitive. This is based on using Markov chains with forbidden transitions.; Comment: to appear in Theoretical Computer Science, 2010