Context Free Grammars Research Papers (original) (raw)

We present Expressionist, an authoring tool for in-game text generation that combines the raw generative power of context-free grammars (CFGs) with the expressive power of free-text markup. Specifically, authors use the tool to define... more

We present Expressionist, an authoring tool for in-game text generation that combines the raw generative power of context-free grammars (CFGs) with the expressive power of free-text markup. Specifically, authors use the tool to define CFGs whose nonterminal symbols may be annotated using arbitrary author-defined tagsets. Any content generated by the CFG comes packaged with explicit metadata in the form of the markup attributed to all the symbols that were expanded to produce the content. Expressionist has already been utilized in two released games and it is currently being used in two ongoing projects. In this paper, we describe the tool and discuss these usage examples in a series of case studies. Expressionist is planned for release in late 2016.

We extend the Expressionist project, and thereby the re-emerging area of grammar-based text generation, by applying a technique from software verification to a critical search problem related to content generation from grammars. In... more

We extend the Expressionist project, and thereby the re-emerging area of grammar-based text generation, by applying a technique from software verification to a critical search problem related to content generation from grammars. In Expressionist, authors attach tags (corresponding to pertinent meanings) to nonterminal symbols in a context-free grammar , which enables the targeted generation of content that expresses requested meanings (i.e., has the requested tags). While previous work has demonstrated methods for requesting content with a single required tag, requests for multiple tags yields a search task over domains that may realistically span quintillions or more elements. In this paper, we reduce Expressionist grammars to symbolic visibly pushdown automata, which allows us to locate in massive search spaces generable outputs that satisfy moderately complex criteria related to tags. While the satisficing of more complex tag criteria is still not feasible using this technique, we forecast a number of opportunities for future directions.

This paper describes the use of Naive Bayes to address the task of assigning function tags and context free grammar(CFG) to parse Myanmar sentences.Part of the challenge of statistical function tagging for Myanmar sentences comes from the... more

This paper describes the use of Naive Bayes to address the task of assigning function tags and context free grammar(CFG) to parse Myanmar sentences.Part of the challenge of statistical function tagging for Myanmar sentences comes from the fact that Myanmar has free -phrase-order and a complex morphological system.Function tagging is a pre-processing step for parsing. In the task of function tagging,we use the functional annotated corpus and tag Myanmar sentences with correct segmentation,POS (part-of-speech) tagging and chunking information.We propose Myanmar grammar rules and apply context free grammar (CFG) to find out the parse tree of function tagged Myanmar sentences. Experiments show that our analysis achieves a good result with parsing of simple sentences and three types of complex sentences.

This paper discusses the consequences of allowing discontinuous constituents in syntactic representions and phrase-structure rules, and the resulting complications for a standard parser of phrase-structure grammar.It is argued, first,... more

This paper discusses the consequences of allowing discontinuous constituents in syntactic representions and phrase-structure rules, and the resulting complications for a standard parser of phrase-structure grammar.It is argued, first, that discontinuous constituents seem inevitable in a phrase-structure grammar which is acceptable from a semantic point of view. It is shown that tree-like constituent structures with discontinuities can be given a

Abstrac Lovebirds is one of bird which has unique chirping sound and unique of color to attract the majority of bird lovers in Indonesia. For the general public as well as the hobbyist bird Lovebirds novice difficult to determine the type... more

Abstrac Lovebirds is one of bird which has unique chirping sound and unique of color to attract the majority of bird lovers in Indonesia. For the general public as well as the hobbyist bird Lovebirds novice difficult to determine the type of each bird Lovebirds they met as well as they have. Therefore the expert system is designed to provide solutions to the people who were involved in the Lovebirds world to identify their species. This expert system works based in the theory, the rule and a knowledge base. The theory to used is Context Free Languages theory (Context Free Grammars), which is a way to show how to generate a strands in a language where there are no restrictions on their products. Context Free Grammar theory used in this application to generate a word that indicates a particular species of Lovebirds based on the rule. Program application was resulting is web-based applications who was using the programming language PHP and MySQL as database. The results of this study in an expert system application to identify the species of birds Lovebirds by color using a web-based Context Free Grammar. By testing a sample of 10 input data test and 5 input data of Lovebirds species on expert system obtained up to a maximum accuracy of 100%. Abstrak Burung Lovebirds merupakan salah satu burung yang memiliki keunikan dalam bidang suara kicau maupun warna yang mampu memikat sebagian besar pecinta burung di Indonesia. Bagi masyarakat umum maupun penghobi burung Lovebirds pemula sulit untuk mengetahui jenis setiap burung Lovebirds yang mereka jumpai maupun yang mereka miliki. Hal ini disebabkan karena minimnya pengetahuan yang mereka miliki tentang burung Lovebirds. Oleh sebab itu system pakar ini dibuat untuk memberikan solusi kepada masyarakat yang terjun di dunia Lovebirds untuk mengidentifikasi jenisnya. Sistem pakar ini bekerja berdasarkan teori, aturan (rule) dan basis pengetahuan. Teori yang digunakan ialah Teori Bahasa Bebas Konteks (Context Free Grammars), yaitu suatu cara untuk menunjukkan bagaimana menghasilkan suatu untai-untai dalam sebuah bahasa

In this research paper, authors proposed an approach in which the size reduction and speed enhancement of file or document takes place and to achieve this process, methods of grey scale in Digital Image Processing, which refers to... more

In this research paper, authors proposed an approach in which the size reduction and speed enhancement of file or document takes place and to achieve this process, methods of grey scale in Digital Image Processing, which refers to processing of digital images by means of a digital computer; Chomsky Normal Form (CNF) process for merging in one of the three forms namely, two non-terminal symbol, one terminal symbol or null; and process splitting through context free grammar (CFG), is used. In initial procedure for a file, we have to allocate two places for a file. The first one is non-converted (original file) and the other one is converted (greyscale file), which has reduced the size of a file. Thereafter, further splitting of the file is processed by context free grammar. By this approach, split portions allocate an address, which are displayed on the calling of the required part.

This paper is about the development of Pashto Treebank in the form of Extensible Markup Language (XML) code. A Chart Parser has been developed that uses Chart Parsing Algorithm for building parse trees for Pashto sentences. The output of... more

This paper is about the development of Pashto Treebank in the form of Extensible Markup Language (XML) code. A Chart Parser has been developed that uses Chart Parsing Algorithm for building parse trees for Pashto sentences. The output of the parser is the parsed text which can be obtained in one of its three forms such as reduced graph, parse tree and XML code. For parsing, the parser needs Context Free Grammar (CFG) of Pashto language and Tagged Input Text as input. The system has been tested on real world text taken from Pashto novels and web sites and tagged manually. Eighty seven (87) sentences were parsed by the parser in which fifty four (54) were correctly parsed with a single parse tree and the rest 33 were parsed with multiple trees and thus the accuracy obtained is 62.06%.

This paper presents a theoretical model of self-control as a dynamic process. In situations demanding self-control, the individual experiences one of two types of temptations: Impulsiveness or procrastination, followed by an inner... more

This paper presents a theoretical model of self-control as a dynamic process. In situations demanding self-control, the individual experiences one of two types of temptations: Impulsiveness or procrastination, followed by an inner struggle between yielding to and overcoming the temptation. When the individual activates personal resources to overcome mptations, the process of selfcontrol takes place. Individuals vary in their abilities to overcome temptations; some overcome them immediately, while others need to call upon what we define as intrinsic and extrinsic control mechanisms. We suggest that intrinsic control mechanisms are selfactions and thoughts that individuals employ when they need to exert control, whereas extrinsic control mechanisms are actions that address others and seek their help in overcoming the temptation. We present and test the theory with a context-free self-control measure in four studies.

Ellul, Krawetz, Shallit and Wang prove an exponential lower bound on the size of any context-free grammar generating the language of all permutations over some alphabet. We generalize their method and obtain exponential lower bounds for... more

Ellul, Krawetz, Shallit and Wang prove an exponential lower bound on the size of any context-free grammar generating the language of all permutations over some alphabet. We generalize their method and obtain exponential lower bounds for many other languages, among them the set of all squares of given length, and the set of all words containing each symbol at most twice.► We develop a simple method for proving lower bounds on the size of CFGs. ► The method combines a lemma on derivation trees with a simple counting argument. ► Simple applications: generating all permutations, generating all squares. ► Another application: languages defined by allowed symbol counts.

Abstract Current parsing techniques are not appropriate when it comes to large scale software analysis. The techniques that are used in industry (LR, LL, LALR) do not support full CF grammars and require severe changes to the grammar,... more

Abstract Current parsing techniques are not appropriate when it comes to large scale software analysis. The techniques that are used in industry (LR, LL, LALR) do not support full CF grammars and require severe changes to the grammar, moreover they are not compositional. The current replacement of generalized (scannerless) LR parsing being developed at CWI in Amsterdam is heavily used

Let L range over all natural languages (NLs). For any L, one can consider two collections of strings of symbols, one consisting of all strings over the terminal vocabulary of L, call it W*(L), the other consisting of that always very... more

Let L range over all natural languages (NLs). For any L, one can consider two collections of strings of symbols, one consisting of all strings over the terminal vocabulary of L, call it W*(L), the other consisting of that always very proper subcollection of W*(L) consisting of all and only those members of W*(L) that are well-formed, that is, that

Resumen: En este artículo se menciona cómo el resurgimiento del estudio de los Conjuntos de Julia se dio gracias a la difusión de las computadoras personales y luego se propone la vía artística para aumentar y enriquecer la imagen mental... more

Resumen: En este artículo se menciona cómo el resurgimiento del estudio de los Conjuntos de Julia se dio gracias a la difusión de las computadoras personales y luego se propone la vía artística para aumentar y enriquecer la imagen mental sobre los Conjuntos de Julia. Esta vía incluye lo matemático, lo lúdico, lo artístico y lo computacional; y se argumenta que no son disjuntos ni disociados a pesar del rechazo general por parte de las comunidades académicas tradicionales y de las comunidades de críticos de arte. Después se mencionan algunas colecciones significativas de Arte Computacional o Arte Matemático Generado por Computadora, y finalmente se presentan cuatro creaciones artísticas basadas en Conjuntos de Julia a manera de ejemplo utilizando el lenguaje CFDG. Palabras clave: Graficación por Computadora, Fractales, Conjuntos de Julia, CFDG, contextfree, Arte Matemático, Arte Computarizado, Arte Matemático Generado por Computadora. Abstract: This article mentions how the resurgence of the study of Julia Sets was due to the diffusion of personal computers and then the artistic way is proposed to increase and enrich the mental image on Julia Sets. This way includes the mathematical, the playful, the artistic and the computational approach; and it is argued that they are not disjointed or dissociated approaches despite the general rejection by traditional academic communities and art critics communities. Some significant collections of Computational Art or Computer-Generated Mathematical Art are mentioned, and finally four artistic creations based on Julia Sets are presented as an example using the CFDG language.

We show the inadequacy of work done previously to show that Dutch serial verb constructions give rise to strong non-context-freeness, then criticize the whole notion of strong generative capacity. Next we show that by playing the game... more

We show the inadequacy of work done previously to show that Dutch serial verb constructions give rise to strong non-context-freeness, then criticize the whole notion of strong generative capacity. Next we show that by playing the game the way it has usually been played (and it is a game), we can show that Dutch is weakly non-context-free, and moreover that is also beyond the weak generative capacity of the two formalisms then much talked-about (head grammars and various kinds of TAGs, even brand new ones just then being developed) based on more complex kinds of examples that had been considered in the literature before, such as Of Jan Piet Marie liet opbellen, hoorde uitnodigen, hielp ontmoeten en zag omhelzen. In the various mathematical proofs we use some absolutely obvious (trival) techniques that nevertheless had not been used in math ling before (and as we recall caused a little problem with referees and editors) including one that allows one to construct such proofs for "leaky" grammars (where we are not sure just what is and what is not grammatical). And then, as usual, we argue that all such weak generative capacity work is also a red herring and plead for the need to study the formal properties not of whole languages but of (Bloomfield-style) CONSTRUCTIONS. Oh the foolishness of youth!

This paper reports on an ongoing attempt to develop an author-friendly approach to procedural game dialogue generation. Various affordances of the experimental authoring tool Expressionist are appropriated to allow non-computer scientist... more

This paper reports on an ongoing attempt to develop an author-friendly approach to procedural game dialogue generation. Various affordances of the experimental authoring tool Expressionist are appropriated to allow non-computer scientist authors to design virtual characters' discourse and reasoning potential. The paper describes how the Hammurabi game project makes use of metadata-driven context free grammars to author virtual characters that can generate not only discourse but also context-relevant decisions. The author-friendliness and generativity of the approach is discussed.

ABSTRACT enetic Programming has been used for the automatic creation of heuristics to address problems of boolean satisfiability and other complex computational problems. This paper presents a methodology to evolve variable ordering... more

ABSTRACT enetic Programming has been used for the automatic creation of heuristics to address problems of boolean satisfiability and other complex computational problems. This paper presents a methodology to evolve variable ordering heuristics for constraint satisfaction problems, though a hyper-heuristic model based on genetic programming and a context-free grammar. We present an analysis of the efficiency of new heuristics generated against human-design heuristics and the generality level reached by solving instances with different parameterization, as well as an analysis of the behavior of heuristics generated with different training instances over the problem domain. The results show that in most of cases, the heuristics generated by our approach overcome the performance of human-design heuristic.

The parsing schemata formalism allows us to describe parsing algorithms in a simple way by capturing their fundamental semantics while abstracting low-level detail. In this work, we present a compilation technique allowing automatic... more

The parsing schemata formalism allows us to describe parsing algorithms in a simple way by capturing their fundamental semantics while abstracting low-level detail. In this work, we present a compilation technique allowing automatic trans- formation of parsing schemata to executable implementations of their corresponding algorithms. Taking a simple description of a schema as input, our technique gene- rates Java code for the corresponding parsing algorithm, including schema-specific indexing code in order to attain efficiency. Our technique is general enough to be able to handle all kinds of schemata for context-free grammars, providing an exten- sibility mechanism which allows the user to define custom notational elements, and it could also be easily generalized to other grammatical formalisms.

We introduce a new variant of membrane systems where the rules are directly assigned to membranes (and not to the regions as this is usually observed in the area of membrane systems) and, moreover, every membrane carries an energy value... more

We introduce a new variant of membrane systems where the rules are directly assigned to membranes (and not to the regions as this is usually observed in the area of membrane systems) and, moreover, every membrane carries an energy value that can be changed during a computation by objects passing through the membrane. For the application of rules leading from