1,649 research outputs found
Uniform representation of transition concepts in Domain Specific Visual Languages
No full textDomain specic visual languages are generally used to specify signicant congurations and behaviours of systems of interest for the users and diagrams of dierent types can be used to specify
dierent components of a single system. At an abstract level, all these diagrams express some form of transformation of the system, which can be characterised by its pre- and post-conditions and by a policy presiding at its execution. We propose a uniform approach to the management of these transitions, independently of the adopted diagrammatic notation, which can be used for bidirectional binding between modications of the visual representation and the transformations
of the underlying model
1986 IEEE Computer Society Workshop on Visual Languages June 25 - 27, 1986, Dallas, Texas, U.S.A.
No full textAn 00 visual language definition approach supporting multiple views
No full textThe formal approach to visual language definition is to use graph grammars and/or graph transformation techniques. These techniques focus on specifying the syntax and manipulation rules of the concrete representation. This paper presents a constraint and object-oriented approach to defining visual languages that uses UML and OCL as a definition language. Visual language definitions specify a mapping between concrete and abstract models of possible visual sentences, which carl subsequently be used to determine if instances of each model "validly" express each other. This technique supports many:many mappings between concrete and abstract model instances, and supports the implementation of functionality that requires feedback from the abstract domain to the concrete
A Graph Rewriting Visual Language for Database Programming
No full textTextual database programming languages are computationally complete, but have the disadvantage of giving the user a non-intuitive view of the database information that is being manipulated. Visual languages developed in recent years have allowed naive users access to a direct representation of data, often in a graph form, but have concentrated on user interface rather than complex programming tasks. There is a need for a system which combines the advantages of both these programming methods. We describe an implementation of Spider, an experimental visual database programming language aimed at programmers. It uses a graph rewriting paradigm as a basis for a fully visual, computationally complete language. The graphs it rewrites represent the schema and instances of a database. The unique graph rewriting method used by Spider has syntactic and semantic simplicity. Its form of algorithmic expression allows complex computation to be easily represented in short programs. Furthermore, Spider has greater power than normally provided in textual systems, and we show that queries on the schema and associative queries can be performed easily and without requiring any additions to the language
A graph rewriting programming language for graph drawing
No full textThis paper describes Grrr, a prototype visual graph drawing tool. Previously there were no visual languages for programming graph drawing algorithms despite the inherently visual nature of the process. The languages which gave a diagrammatic view of graphs were not computationally complete and so could not be used to implement complex graph drawing algorithms. Hence current graph drawing tools are all text based. Recent developments in graph rewriting systems have produced computationally complete languages which give a visual view of graphs both whilst programming and during execution. Grrr, based on the Spider system, is a general purpose graph rewriting programming language which has now been extended in order to demonstrate the feasibility of visual graph drawing
A Visual Language for Web Querying and Reasoning
No full textAs XML is increasingly being used to represent information on the Web, query and reasoning languages for such data are needed. This article argues that in contrast to the navigational approach taken in particular by XPath and XQuery, a positional approach as used in the language Xcerpt is better suited for a straightforward visual representation. The constructs of the pattern- and rule-based query language Xcerpt are introduced and it is shown how the visual representation visXcerpt renders these constructs to form a visual query language for XML
Generalized parser for 2-D languages
No full textIn this paper we will present an extension of the Earley's generalized parser to the case of two-dimensional languages. To do this we describe two-dimensional (positional) grammars as generalizations of the context-free string grammars. The technique used to extend the Earley's algorithm is the same used for constructing a positional LR (pLR) parser. The main idea is to allow the parser to choose the next symbol to parse from a two-dimensional space
Tagging of Biomedical Articles on CiteULike: A Comparison of User, Author and Professional Indexing
No full textThis paper examines the context of online indexing from the viewpoint of three different groups: users, authors, and professional indexers. User tags, author keywords and descriptors were collected from academic journal articles, which were both indexed in Pubmed and tagged on CiteULike, and analysed. Descriptive statistics, informetric measures, and thesaural term comparison shows that there are important differences in the use of keywords between the three groups in addition to similarities which can be used to enhance support for search and browse. While tags and author keywords were found that matched descriptors exactly, other terms which did not match but provided important expansion to the indexing lexicon were found. These additional terms could be used to enhance support for searching and browsing in article databases as well as to provide invaluable data for entry vocabulary and emergent terminology for regular updates to indexing systems. Additionally, the study suggests that tags support organisation by association to task, projects and subject while making important connections to traditional systems which classify into subject categories
On the expressiveness of spider diagrams and commutative star-free regular languages
No full textSpider diagrams provide a visual logic to express relations between sets and their elements, extending the expressiveness of Venn diagrams. Sound and complete inference systems for spider diagrams have been developed and it is known that they are equivalent in expressive power to monadic first-order logic with equality, MFOL[=]. In this paper, we further characterize their expressiveness by articulating a link between them and formal languages. First, we establish that spider diagrams define precisely the languages that are finite unions of languages of the form K {black small square} ?*, where K is a finite commutative language and ? is a finite set of letters. We note that it was previously established that spider diagrams define commutative star-free languages. As a corollary, all languages of the form K {black small square} ?* are commutative star-free languages. We further demonstrate that every commutative star-free language is also such a finite union. In summary, we establish that spider diagrams define precisely: (a) languages definable in MFOL[=], (b) the commutative star-free regular languages, and (c) finite unions of the form K {black small square} ?*, as just described
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