93 results about "Context-free grammar" patented technology

An apparatus and system for analyzing intention are provided. The apparatus for analyzing an intention applies a context-free grammar to each of one or more sentences in units of one or more phrases to perform phrase spotting on each sentence, thereby extending a recognition range for an out-of-grammar (OOG) expression. Meanwhile, the apparatus for analyzing an intention determines whether sentences that have undergone phrase spotting are grammatically valid by applying a dependency grammar to the sentences to filter an invalid sentence, and generates the intention analysis result of a valid sentence, thereby and grammatically and/or semantically verifying a sentence that has undergone speech recognition while extending a speech recognition range.

A speech understanding system includes a language model comprising a combination of an N-gram language model and a context-free grammar language model. The language model stores information related to words and semantic information to be recognized. A module is adapted to receive input from a user and capture the input for processing. The module is further adapted to receive SALT application program interfaces pertaining to recognition of the input. The module is configured to process the SALT application program interfaces and the input to ascertain semantic information pertaining to a first portion of the input and output a semantic object comprising text and semantic information for the first portion by accessing the language model, wherein performing recognition and outputting the semantic object are performed while capturing continues for subsequent portions of the input.

A context-free grammar can be represented by a weighted finite-state transducer. This representation can be used to efficiently compile that grammar into a weighted finite-state automaton that accepts the strings allowed by the grammar with the corresponding weights. The rules of a context-free grammar are input. A finite-state automaton is generated from the input rules. Strongly connected components of the finite-state automaton are identified. An automaton is generated for each strongly connected component. A topology that defines a number of states, and that uses active ones of the non-terminal symbols of the context-free grammar as the labels between those states, is defined. The topology is expanded by replacing a transition, and its beginning and end states, with the automaton that includes, as a state, the symbol used as the label on that transition. The topology can be fully expanded or dynamically expanded as required to recognize a particular input string.

A method for creating a language model from a task-independent corpus is provided. In one embodiment, a task dependent unified language model is created. The unified language model includes a plurality of context-free grammars having non-terminals and a hybrid N-gram model having at least some of the same non-terminals embedded therein.

A discriminative grammar framework utilizing a machine learning algorithm is employed to facilitate in learning scoring functions for parsing of unstructured information. The framework includes a discriminative context free grammar that is trained based on features of an example input. The flexibility of the framework allows information features and/or features output by arbitrary processes to be utilized as the example input as well. Myopic inside scoring is circumvented in the parsing process because contextual information is utilized to facilitate scoring function training.

A method of generating a parser of a source code file that references a syntactic dictionary, a method of compressing the file, and apparatuses that use the methods. The syntactic dictionary is converted into a corresponding plurality of expressions, of a context-free grammar, that are a grammar of the source code. The parser is constructed from the expressions. The source code is compressed using the parser. Preferably, the grammar of the source code file is a D-grammar and the expressions are regular expressions. Preferably, the parser is a deterministic pushdown transducer. An important case of the present invention is that in which the source code is XML code and the syntactic dictionary is the document type declaration of the XML code. Apparatuses that use a parser of the present invention include compressors, decompressors, validators, converters, editors, network devices and end-user/hand-held devices.

A method and system for use in a natural language understanding system for including grammars within a statistical parser. The method involves a series of steps. The invention receives a text input. The invention applies a first context free grammar to the text input to determine substrings and corresponding parse trees, wherein the substrings and corresponding parse trees further correspond to the first context free grammar. Additionally, the invention can examine each possible substring using an inventory of queries corresponding to the CFG.

Adaptive network traffic classification using historical context. Network traffic may be monitored and classified by considering several attributes using packet filters, regular expressions, context-free grammars, rule sets, and/or protocol dissectors, among other means and by applying a variety of techniques such as signature matching and statistical analysis. Unlike static systems, the classification decisions may be reexamined from time to time or after subsequent processing determines that the traffic does not conform to the protocol specification corresponding to the classification decision. Historical context may be used to adjust the classification strategy for similar or related traffic.

Systems, methods and computer program products for string analysis with security labels for vulnerability detection. Exemplary embodiments include a method in a computer system configured to analyze security-labeled strings and to detect vulnerability, the method including receiving a program with security labels, translating the program into a static single assignment form, constructing a control flow graph having basic blocks as nodes, extracting instructions relating to string functions and object variables, calculating pre-conditions of variables for the basic blocks, extracting constraints among the variables subject to a rule set for translating pre-conditions, solving the constraints and obtaining a set of strings that he object variables form as a context-free grammar to obtain a set of security-labeled strings, checking if the set of security-labeled strings satisfies a rule of the rule set for translating pre-conditions and identifying locations in the program where a vulnerability is detected.

The present invention provides a method and apparatus that utilize a context-free grammar written in a markup language format. The markup language format provides a hierarchical format in which grammar structures are delimited within and defined by a set of tags. The markup language format also provides grammar switch tags that indicate a transitions from the context-free grammar to a dictation grammar or a text buffer grammar. In addition, the markup language format provides for the designation of code to be executed when particular grammar structures are recognized from a speech signal.

A system for discovering data artifacts in an on-line data object is described. One embodiment includes a data acquisition subsystem configured to parse the on-line data object into at least one string; a string pre-parser configured to divide each string into a set of separate characters; a lexical analyzer configured, for each set of separate characters, to aggregate the separate characters in that set of separate characters into a sequence of tokens, each token in the sequence of tokens being one of a word, a punctuation symbol, a HyperText-Markup-Language tag, and a number; a syntax analyzer configured, for each sequence of tokens during a first analysis phase, to determine, for each of a plurality of rule sets, whether the sequence of tokens includes one or more candidate data artifacts of a distinct type to which that rule set corresponds, each of the plurality of rule sets being adapted to discovery of the distinct type of data artifact to which that rule set corresponds, at least one rule set in the plurality of rule sets including a context-free grammar; compute, for each candidate data artifact of a distinct type, a probability ranking indicating a degree of likelihood that the candidate data artifact is a data artifact of that distinct type; and classify each candidate data artifact as a data artifact of the distinct type for which a most favorable probability ranking was computed for that candidate data artifact, the syntax analyzer being configured to associate with each classified data artifact a subject found within the on-line data object; and a storage subsystem including at least one data structure in which to store the classified data artifacts, the storage subsystem being configured to index and organize the classified data artifacts by subject for retrieval in response to a search query indicating a particular subject.

A method and apparatus to use semantic inference with speech recognition systems includes recognizing at least one spoken word, processing the spoken word using a context-free grammar, deriving an output from the context-free grammar, and translating the output to a predetermined command.

In one embodiment, the present system recognizes a user's speech input using an automatically generated probabilistic context free grammar for street names that maps all pronunciation variations of a street name to a single canonical representation during recognition. A tokenizer expands the representation using position-dependent phonetic tokens and an intersection classifier classifies an intersection, despite the presence of recognition errors and incomplete street names.

The embodiments of the present invention disclose an event detection method and device. The method includes: predefining event-based detection rules with a predicative context-free grammar; generating by parsing the detection rules a parsing table of pushdown automaton which supports parallel parsing; receiving an event to be detected; and analyzing by a controller the event to be detected according to the parsing table, to obtain a detection result. The present invention is especially applicable to detection of network attack events. The embodiments of the present invention detect the attacks with a predicative context-free grammar on the basis of events, and ensure a close combination of a protocol parsing process and an attack detection process, as well as a close combination of multiple attack detection rules, thus decreasing unnecessary calculations. In addition, with an optimized parallel pushdown automaton, the embodiments of the present invention can efficiently analyze the predicative context-free grammar. Consequently, besides hierarchical processing capability and state description capability, the embodiments of the present invention deliver high efficiency.

A method for discovering data artifacts in an on-line data object is described. One embodiment parses the on-line data object into at least one string; divides each string into a set of separate characters; for each set of separate characters, aggregates the separate characters in that set of separate characters into a sequence of tokens, each token in the sequence of tokens being one of a word, a punctuation symbol, a HyperText-Markup-Language tag, and a number; for each sequence of tokens during a first analysis phase, determines, for each of a plurality of rule sets, whether the sequence of tokens includes one or more candidate data artifacts of a distinct type to which that rule set corresponds, each of the plurality of rule sets being adapted to discovery of the distinct type of data artifact to which that rule set corresponds, at least one rule set in the plurality of rule sets including a context-free grammar; computes, for each candidate data artifact of a distinct type, a probability ranking indicating a degree of likelihood that the candidate data artifact is a data artifact of that distinct type; and classifies each candidate data artifact as a data artifact of the distinct type for which a most favorable probability ranking was computed for that candidate data artifact; associates with each classified data artifact a subject found within the on-line data object; and stores the classified data artifacts in a storage subsystem that includes at least one data structure, the classified data artifacts in the storage subsystem being indexed and organized by subject for retrieval in response to a search query indicating a particular subject.

A system and method for generating test frames in specification-based testing by using a path-coverage criterion is provided. The method includes receiving a test design as an input, and constructing a context-free grammar graph, based on the test design. The method further includes analyzing the context-free grammar graph to generate a first set of paths, and emitting a set of test frames as an output, based on the first set of paths.

A computer architecture uses a PushDown Automaton (PDA) and a Context Free Grammar (CFG) to process data. A PDA engine maintains semantic states that correspond to semantic elements in an input data set. The PDA engine does not have to maintain a new state for each new character in a target search string and typically only transitions to a new state when the entire semantic element is detected. The PDA engine can therefore use a smaller and more predictable state table than DFA algorithms. Transitions between the semantic states are managed using a stack that allows multiple semantic states to be represented by a single nested non-terminal symbol.

This invention relates to a unit selection module for Chinese Text-to-Speech (TTS) synthesis, mainly comprising a probabilistic context free grammar (PCFG) parser, a latent semantic indexing (LSI) module, and a modified variable-length unit selection scheme; any Chinese sentence is firstly input and then parsed into a context-free grammar (CFG) by the PCFG parser; wherein there are several possible CFGs for every Chinese sentence, and the CFG (or the syntactic structure) with the highest probability is then taken as the best CFG (or the syntactic structure) of the Chinese sentence; the LSI module is then used to calculate the structural distance between all the candidate synthesis units and the target unit in a corpus; through the modified variable-length unit selection scheme, tagged with the dynamic programming algorithm, the units are searched to find the best synthesis unit concatenation sequence.