mirror of https://github.com/2martens/uni.git
423 lines
17 KiB
BibTeX
Executable File
423 lines
17 KiB
BibTeX
Executable File
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@INPROCEEDINGS{Brin1998,
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author = {Brin, Sergey and Page, Lawrence},
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title = {The Anatomy of a Large-Scale Hypertextual Web Search Engine},
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booktitle = {Seventh World Wide Web Conference},
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year = {1998},
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keywords = {World Wide Web, Search Engines, Information Retrieval, PageRank, Google},
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owner = {jim},
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quality = {1},
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timestamp = {2013.10.29}
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}
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@CONFERENCE{Clark2004,
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author = {Clark, Stephen and Curran, James R.},
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title = {Parsing the {WSJ} using {CCG} and Log-Linear Models},
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booktitle = {Proceedings of the 42nd Annual Meeting of the Association for Computational
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Linguistics},
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year = {2004},
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pages = {104-111},
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owner = {jim},
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quality = {1},
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timestamp = {2013.10.29}
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}
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@INBOOK{Jurafsky2009,
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chapter = {18},
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pages = {617--644},
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title = {Speech and Language Processing},
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publisher = {Pearson},
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year = {2009},
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author = {Jurafsky, Daniel and Martin, James H.},
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series = {Prentice-Hall series in artificial intelligence},
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edition = {Second},
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abstract = {Sentences get their meanings from the words they contain and the syntactic
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order of the words. Therefore the meaning of a sentence is partially
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based on the words and its syntactic structure. The composition of
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meaning representation is guided by the syntactic components and
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relations provided by grammars such as CFGs.
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A meaning representation is generated by first sending the input through
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a parser which results in the syntactic analysis and second passing
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this analysis as input to a semantic analyzer.
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In the syntax-driven semantic analysis it is assumed that syntactic,
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lexical and anaphoric ambiguities are not a problem.
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The semantic meanings are attached to the grammar rules and lexical
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entries from which trees are generated in the first place. This is
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called rule-to-rule hypothesis.
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The semantic attachments are written in braces after the syntactic
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rules themselves.
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After the syntactic analysis has been created, every word receives
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a FOL predicate and/or term. The semantic analyzer goes the tree
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up until the complete FOL term has been created. On the way lambda
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reduction is used to replace predicates and terms with their proper
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meanings, received from other parts of the tree.},
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booktitle = {Speech and Language Processing},
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owner = {jim},
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quality = {1},
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timestamp = {2013.11.16}
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}
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@INBOOK{Jurafsky2009a,
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chapter = {17},
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pages = {579--616},
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title = {Speech and Language Processing},
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publisher = {Pearson},
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year = {2009},
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author = {Jurafsky, Daniel and Martin, James H.},
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series = {Prentice-Hall series in artificial intelligence},
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edition = {Second},
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abstract = {Lambda notation is used to bind variables dynamically to later appearing
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contents.
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lambda x P(x)(y) results in P(y) after a lambda reduction as x has
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been bound to y.
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lambda P P(x)(lambda x Restaurant(x)) results in lambda x Restaurant(x)(x)
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which results in Restaurant(x)},
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booktitle = {Speech and Language Processing},
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owner = {jim},
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quality = {1},
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timestamp = {2013.11.16}
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}
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@INBOOK{Jurafsky2009b,
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chapter = {13},
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pages = {461--492},
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title = {Speech and Language Processing},
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publisher = {Pearson},
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year = {2009},
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author = {Jurafsky, Daniel and Martin, James H.},
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series = {Prentice-Hall series in artificial intelligence},
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edition = {Second},
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owner = {jim},
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quality = {1},
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timestamp = {2013.11.17}
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}
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@CONFERENCE{Kessler1997,
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author = {Kessler, Brett and Nunberg, Geoffrey and Schuetze, Hinrich},
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title = {Automatic Detection of Text Genre},
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booktitle = {Proceedings of the 35th Annual Meeting of the Association for Computational
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Linguistics},
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year = {1997},
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pages = {32-38},
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owner = {jim},
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quality = {1},
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timestamp = {2013.10.29}
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}
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@CONFERENCE{Klein2003,
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author = {Klein, Dan and Smarr, Joseph and Nguyen, Huy and Manning, Christopher
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D.},
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title = {Named Entity Recognition with Character-Level Models},
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booktitle = {Conference on Natural Learning (CoNLL)},
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year = {2003},
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pages = {180-183},
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owner = {jim},
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quality = {1},
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timestamp = {2013.10.29}
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}
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@TECHREPORT{Paskin2001,
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author = {Paskin, Mark A.},
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title = {Cubic-time Parsing and Learning Algorithms for Grammatical Bigram
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Models},
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institution = {University of California},
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year = {2001},
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number = {UCB/CSD-01-1148},
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month = {June},
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abstract = {In Dependency Grammar there are head words and dependents. Each phrase
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has only one head word. The head word determines how all of its dependents
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may be syntactically combined with other words to form a sentence.
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A head word and all of its dependents form a constituent. In every
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sentence there may be one or more dependency relationships with one
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head word each.
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Dependents that precede their head are called predependents and dependents
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that follow their head are called postdependents.
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A dependency parse consists of a set of dependency relationships that
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satisfies three constraints: 1. Every word except one (the root)
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is dependent to exactly one head. 2. The dependency relationships
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are acyclic; no word is, through a sequence of dependency relationships,
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dependent to itself. 3. When drawn as a graph above the sentence,
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no two dependency relations cross - a property known as projectivity
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or planarity.
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The Grammatical Bigram Probability Model assumes that all the dependents
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of a head word are independent of one another and their relative
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order. This is a strong approximation as in full English there are
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argument structure constraints that rely on the order of dependents.
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This simplification allows for a reduced computational complexity
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for parsing and learning. The grammar model falls into the class
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of "Bilexical grammars".
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A dependency parse consists of multiple spans. A span has at least
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two words up to n words. Spans have one property: No word in the
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span has a parent outside the span. Spans can be joined and closed.
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To join the span one of them has to be connected (both end words
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are connected with an edge) and both spans have to share one endword.
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The new span will be connected if both subspans were connected. If
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that is not the case, it can be closed by adding an edge between
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the endwords of the new span.
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Every dependency parse has a unique span decomposition. For joining
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the left subspan has be simple. That means it has to have an edge
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between its endwords or consist of two words only. Relying on this
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ensures that each span is derived only once.
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Every span has a signature. This signature states the indexes of its
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endwords, if it is simple and whether the left or right endword have
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parents within the span. Spans where both the left and right endword
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have the parent within the string are called toplevel signatures
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as such signatures characterize valid parses.
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Parser operations take signatures as input rather than spans. They
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produce signatures as well. SEED creates an unconnected and simple
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span with two adjacent words. CLOSE-LEFT adds an edge between the
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endwords and makes the left endword the parent of the right one.
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CLOSE-RIGHT does the opposite and makes the right endword the parent
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of the left one. These operators require that neither the left nor
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the right endword have a parent within the span.
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JOIN takes two input spans and joins them. It requires that the spans
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share an endword (1.), the shared endword has one parent (2.) and
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the left input is simple (3.). The JOIN rule applies only if the
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left span doesn't start the sentence.
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These operators constitute an algebra over span signatures called
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span signature algebra. A derivation D is an expression in this algebra.
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Like operations it evaluates to span signatures. These expressions
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can be represented as trees where the nodes are operations. There
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is an isomorphism between dependency parses and their corresponding
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derivations.
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Optimal derivation must consist of an operation over the results of
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optimal sub-derivations. Therefore it is enough to record the parse
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operation with the most likely derivation of a given signature in
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order to reconstruct the most likely derivation of the entire sentence.
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The chart-parse algorithm returns the optimal parse. It uses a subprocedure
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called EXTRACT-OPT-PARSE that constructs the optimal parse by finding
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the top-level signature (sigma) with maximum optimal probability
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(pi*). It backtracks then recursively through the optimal derivation
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defined by (omega*). If CLOSE operations are encountered edges are
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recorded in the parse. The algorithm requires O(n<>) time and O(n<>)
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space.},
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owner = {jim},
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quality = {1},
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timestamp = {2013.10.29}
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}
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@INBOOK{Russel2010,
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chapter = {23},
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pages = {888--927},
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title = {Artificial intelligence: A Modern Approach},
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publisher = {Pearson},
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year = {2009},
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author = {Russel, Stuart J. and Norvig, Peter},
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series = {Prentice-Hall series in artificial intelligence},
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edition = {Third},
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abstract = {The first method to understanding natural language is syntactic analysis
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or parsing. The goal is to find the phrase structure of a sequence
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of words according to the rules of the applied grammar.
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A strict top-to-bottom or bottom-to-top parsing can be inefficient.
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Given two sentences with the same first 10 words and a difference
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only from the 11th word on, parsing from left-to-right would force
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the parser to make a guess about the nature of the sentence. But
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it doesn't know if it's right until the 11th word. From there it
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had to backtrack and reanalyze the sentence.
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To prevent that dynamic programming is used. Every analyzed substring
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gets stored for later. Once it is discovered that for example "the
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students in section 2 of Computer Science 101" is a noun phrase,
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this information can be stored in a structure known as chart. Algorithms
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that do such storing are called chart parsers. One of this chart
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parsers is a bottom-up version called CYK algorithm after its inventors
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John Cocke, Daniel Younger and Tadeo Kasami. This algorithm requires
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a grammar in the Chomsky Normal Form. The algorithm takes O(n<>m)
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space for the P table with n being the number of words in the sentence
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and m the number of nonterminal symbols in the grammar. It takes
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O(n<>m) time whereas m is constant for a particular grammar. That's
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why it is commonly described as O(n<>). There is no faster algorithm
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for general context-free grammars.
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The CYK algorithm only co mputes the probability of the most probable
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tree. The subtrees are all represented in P table.
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PCFGs (Probabilistic context free grammars) have many rules with a
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probability for each one of them. Learning the grammar from data
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is better than a knowledge engineering approach. Learning is easiest
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if we are given a corpus of correctly parsed sentences; commonly
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known as a treebank. The best known treebank is the Penn Treebank
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as it consists of 3 million words which have been annotated with
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part of speech and parse-tree structure. Given an amount of trees,
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a PCFG can be created just by counting and smoothing.
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If no treebank is given it is still possible to learn the grammar
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but it is more difficult. In such a case there are actually two problems:
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First learning the structure of the grammar rules and second learning
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the probabilities associated with them.
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PCFGs have the problem that they are context-free. Combining a PCFG
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and Markov model will get the best of both. This leads ultimately
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to lexicalized PCFGs. But another problem of PCFGs is there preference
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for short sentences.
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Lexicalized PCFGs introduce so called head words. Such words are the
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most important words in a phrase and the probabilities are calculated
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between the head words. Example: "eat a banana" "eat" is the head
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of the verb phrase "eat a banana", whereas "banana" is the head of
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the noun phrase "a banana". Probability P1 now depends on "eat" and
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"banana" and the result would be very high. If the head of the noun
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phrase were "bandanna", the result would be significantly lower.
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The next step are definite clause grammars. They can be used to parse
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in a way of logical inference and makes it possible to reason about
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languages and strings in many different ways. Furthermore augmentations
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allow for distinctions in a single subphrase. For example the noun
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phrase (NP) depends on the subject case and the person and number
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of persons. A real world example would be "to smell". It is "I smell",
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"you smell", "we smell", "you smell" and "they smell" but "he/she/it
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smells". It depends on the person what version is taken.
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Semantic interpretation is used to give sentences a meaning. This
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is achieved through logical sentences. The semantics can be added
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to an already augmented grammar (created during the previous step),
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resulting in multiple augmentations at the same time. Chill is an
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inductive logic programming program that can learn to achieve 70%
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to 85% accuracy on various database query tasks.
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But there are several complications as English is endlessly complex.
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First there is the time at which things happened (present, past,
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future). Second you have the so called speech act which is the speaker's
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action that has to be deciphered by the hearer. The hearer has to
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find out what type of action it is (a statement, a question, an order,
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a warning, a promise and so on). Then there are so called long-distance
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dependencies and ambiguity. The ambiguity can reach from lexical
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ambiguity where a word has multiple usages, over syntactic ambiguity
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where a sentence has multiple parses up to semantic ambiguity where
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the meaning of and the same sentence can be different. Last there
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is ambiguity between literal meaning and figurative meanings.
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Finally there are four models that need to be combined to do disambiguation
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properly: the world model, the mental model, the language model and
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the acoustic model.
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-- not so much an abstract of the specific content of that section
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as an abstract about speech recognition in general --
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The second method is speech recognition. It has the added difficulty
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that the words are not clearly separated and every speaker can pronounce
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the same sentence with the same meaning different. An example is
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"The train is approaching". Another written form would be "The train's
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approaching". Both convey the same meaning in the written language.
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But if a BBC, a CNN and a german news anchor speeks this sentence
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it will sound dramatically different. Speech recognition has to deal
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with that problem to get the written text associated with the spoken
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words. From the text the first method can than be used to analyze
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the words and find a meaning. Finally this meaning can be used to
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create some kind of action in a dialog system.
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--
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Some problems of speech recognition are segmentation, coarticulation
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and homophones. Two used models are the acoustic model and the language
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model. Another major model is the noisy channel model, named after
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Claude Shannon (1948). He showed that the original message can always
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be recovered in a noisy channel if the original message is encoded
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in a redundant enough way.
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The acoustic model in particular is used to get to the really interesting
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parts. It is not interesting how words were spoken but more what
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words where spoken. That means that not all available information
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needs to be stored and a relative low sample rate is enough. 80 samples
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at 8kHz with a frame length of about 10 milliseconds is enough for
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that matter. To distinguish words so called phones are used. There
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are 49 phones used in English. A phoneme is the smallest unit of
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sound that has a distinct meaning to speakers of a particular language.
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Back to the frames: every frame is summarized by a vector of features.
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Features are important aspects of a speech signal. It can be compared
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to listening to an orchestra and saying "here the French horns are
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playing loudly and the violins are playing softly". Yet another difficulty
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are dialect variations.
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The language model should be learned from a corpus of transcripts
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of spoken language. But such a thing is more difficult than building
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an n-gram model of text, because it requires a hidden Markov model.
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All in all speech recognition is most effective when used for a specific
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task against a restricted set of options. A general purpose system
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can only work accurately if it creates one model for every speaker.
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Prominent examples like Apple's siri are therefore not very accurate.},
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bookauthor = {Russel, Stuart J. and Norvig, Peter},
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||
booktitle = {Artificial intelligence: A Modern Approach},
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||
date = {December 11},
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||
owner = {jim},
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||
timestamp = {2013.10.24}
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||
}
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||
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@INPROCEEDINGS{Sleator1993,
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||
author = {Sleator, Daniel D. K. and Temperley, Davy},
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||
title = {Parsing English with a Link Grammar},
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||
booktitle = {Third Annual Workshop on Parsing technologies},
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||
year = {1993},
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||
owner = {jim},
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||
quality = {1},
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||
timestamp = {2013.10.29}
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||
}
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||
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||
@CONFERENCE{Smith2008,
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||
author = {Smith, David A. and Eisner, Jason},
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||
title = {Dependency Parsing by Belief Propagation},
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||
booktitle = {Conference on Empirical Methods in Natural Language Processing},
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||
year = {2008},
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||
pages = {145-156},
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||
date = {October 25 - October 27},
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||
owner = {jim},
|
||
quality = {1},
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||
timestamp = {2013.10.29}
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||
}
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||
|