Exploiting XPG for Visual Languages Definition, Analysis and Development

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A Language Description is More than a Metamodel

Within the context of (software) language engineering, language descriptions are considered first class citizens. One of the ways to describe languages is by means of a metamodel, which represents the abstract syntax of the language. Unfortunately, in this process many language engineers forget the fact that a language also needs a concrete syntax and a semantics. In this paper I argue that neither of these can be discarded from a language description. In a good language description the abstract syntax is the central element, which functions as pivot between concrete syntax and semantics. Furthermore, both concrete syntax and semantics should be described in a well-defined formalism

A Dynamic Stroke Segmentation Technique for Sketched Symbol Recognition

In this paper, we address the problem of ink parsing, which tries to identify distinct symbols from a stream of pen strokes. An important task of this process is the segmentation of the users’ pen strokes into salient fragments based on geometric features. This process allows users to create a sketch symbol varying the number of pen strokes, obtaining a more natural drawing environment. The proposed sketch recognition technique is an extension of LR parsing techniques, and includes ink segmentation and context disambiguation. During the parsing process, the strokes are incrementally segmented by using a dynamic programming algorithm. The segmentation process is based on templates specified in the productions of the grammar specification from which the parser is automatically constructed

Towards Syntax-Aware Editors for Visual Languages

AbstractEditors for visual languages should provide a user-friendly environment supporting end users in the composition of visual sentences in an effective way. Syntax-aware editors are a class of editors that prompt users into writing syntactically correct programs by exploiting information on the visual language syntax. In particular, they do not constrain users to enter only correct syntactic states in a visual sentence. They merely inform the user when visual objects are syntactically correct. This means detecting both syntax and potential semantic errors as early as possible and providing feedback on such errors in a non-intrusive way during editing. As a consequence, error handling strategies are an essential part of such editing style of visual sentences.In this work, we develop a strategy for the construction of syntax-aware visual language editors by integrating incremental subsentence parsers into free-hand editors. The parser combines the LR-based techniques for parsing visual languages with the more general incremental Generalized LR parsing techniques developed for string languages. Such approach has been profitably exploited for introducing a noncorrecting error recovery strategy, and for prompting during the editing the continuation of what the user is drawing

Exploiting Visual Languages Generation and UML Meta Modeling to Construct Meta-CASE Workbenches

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MID: A MetaCASE Tool For A Better Reuse Of Visual Notations

International audienceModeling tools facilitate the development process from modeling to coding. Such tools can be designed using a Model-Driven approach into metamodeling environments called metaCASE tools. It turned out that current metaCASE tools still require, in most cases, manual programming to build full tool support for the modeling language. First of all, we want to specify, using models, diagrams editors with a high graphical expressiveness without any need for manual intervention to perform this task. The second axis is dedicated to this specification reuse in other contexts of use. The redundancy of diagrams editors specification raises the problem of inconsistency during the evolution or the update of this specification. We propose then MID, a tool based on a set of meta-models supporting the easy specification of modeling editors with reusable components

Detecting dressing failures using temporal–relational visual grammars

Evaluation of dressing activities is essential in the assessment of the performance of patients with psycho-motor impairments. However, the current practice of monitoring dressing activity (performed by the patients in front of the therapist) has a number of disadvantages when considering the personal nature of dressing activity as well as inconsistencies between the recorded performance of the activity and performance of the same activity carried out in the patients’ natural environment, such as their home. As such, a system that can evaluate dressing activities automatically and objectively would alleviate some of these issues. However, a number of challenges arise, including difficulties in correctly identifying garments, their position in the body (partially of fully worn) and their position in relation to other garments. To address these challenges, we have developed a novel method based on visual grammars to automatically detect dressing failures and explain the type of failure. Our method is based on the analysis of image sequences of dressing activities and only requires availability of a video recording device. The analysis relies on a novel technique which we call temporal–relational visual grammar; it can reliably recognize temporal dressing failures, while also detecting spatial and relational failures. Our method achieves 91% precision in detecting dressing failures performed by 11 subjects. We explain these results and discuss the challenges encountered during this work

A System For Visual Role-Based Policy Modelling

The definition of security policies in information systems and programming applications is often accomplished through traditional low level languages that are difficult to use. This is a remarkable drawback if we consider that security policies are often specified and maintained by top level enterprise managers who would probably prefer to use simplified, metaphor oriented policy management tools. To support all the different kinds of users we propose a suite of visual languages to specify access and security policies according to the role based access control (RBAC) model. Moreover, a system implementing the proposed visual languages is proposed. The system provides a set of tools to enable a user to visually edit security policies and to successively translate them into (eXtensible Access Control Markup Language) code, which can be managed by a Policy Based Management System supporting such policy language. The system and the visual approach have been assessed by means of usability studies and of several case studies. The one presented in this paper regards the configuration of access policies for a multimedia content management platform providing video streaming services also accessible through mobile devices

Alternativa de Comprobación sintáctica de VLP: Gsig Parsing : Aspectos formales y el caso de estudio: E_GraPiCO

En esta publicación se presenta Gsig Parsing, una alternativa de un mecanismo de comprobación sintáctica para lenguajes visuales por medio de la división del parsing en dos etapas, los Análisis Independientes de Contexto y los Sensibles al Contexto. Como un ejemplo real de la nueva forma propuesta se muestra el editor de programas visuales E GraPiCO.This publication presents Gsig Parsing, an alternative syntactic testing mechanism for visual languages through the division of parsing in two stages, context-free and context-dependent analisis. As a real example of the new proposed form, the visual programm editor E GraPiCO is shown.Red de Universidades con Carreras en Informática (RedUNCI

Alternativa de Comprobación sintáctica de VLP: Gsig Parsing : Aspectos formales y el caso de estudio: E_GraPiCO

En esta publicación se presenta Gsig Parsing, una alternativa de un mecanismo de comprobación sintáctica para lenguajes visuales por medio de la división del parsing en dos etapas, los Análisis Independientes de Contexto y los Sensibles al Contexto. Como un ejemplo real de la nueva forma propuesta se muestra el editor de programas visuales E GraPiCO.This publication presents Gsig Parsing, an alternative syntactic testing mechanism for visual languages through the division of parsing in two stages, context-free and context-dependent analisis. As a real example of the new proposed form, the visual programm editor E GraPiCO is shown.Red de Universidades con Carreras en Informática (RedUNCI