10,278 research outputs found
Strategic programming on graph rewriting systems
We describe a strategy language to control the application of graph rewriting
rules, and show how this language can be used to write high-level declarative
programs in several application areas. This language is part of a graph-based
programming tool built within the port-graph transformation and visualisation
environment PORGY.Comment: In Proceedings IWS 2010, arXiv:1012.533
Higher-order port-graph rewriting
The biologically inspired framework of port-graphs has been successfully used
to specify complex systems. It is the basis of the PORGY modelling tool. To
facilitate the specification of proof normalisation procedures via graph
rewriting, in this paper we add higher-order features to the original
port-graph syntax, along with a generalised notion of graph morphism. We
provide a matching algorithm which enables to implement higher-order port-graph
rewriting in PORGY, thus one can visually study the dynamics of the systems
modelled. We illustrate the expressive power of higher-order port-graphs with
examples taken from proof-net reduction systems.Comment: In Proceedings LINEARITY 2012, arXiv:1211.348
Graph Creation, Visualisation and Transformation
We describe a tool to create, edit, visualise and compute with interaction
nets - a form of graph rewriting systems. The editor, called GraphPaper, allows
users to create and edit graphs and their transformation rules using an
intuitive user interface. The editor uses the functionalities of the TULIP
system, which gives us access to a wealth of visualisation algorithms.
Interaction nets are not only a formalism for the specification of graphs, but
also a rewrite-based computation model. We discuss graph rewriting strategies
and a language to express them in order to perform strategic interaction net
rewriting
Needed Computations Shortcutting Needed Steps
We define a compilation scheme for a constructor-based, strongly-sequential,
graph rewriting system which shortcuts some needed steps. The object code is
another constructor-based graph rewriting system. This system is normalizing
for the original system when using an innermost strategy. Consequently, the
object code can be easily implemented by eager functions in a variety of
programming languages. We modify this object code in a way that avoids total or
partial construction of the contracta of some needed steps of a computation.
When computing normal forms in this way, both memory consumption and execution
time are reduced compared to ordinary rewriting computations in the original
system.Comment: In Proceedings TERMGRAPH 2014, arXiv:1505.0681
A graph rewriting programming language for graph drawing
This 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
Exploiting the Hierarchical Structure of Rule-Based Specifications for Decision Planning
Rule-based specifications have been very successful as a declarative approach in many domains, due to the handy yet solid foundations offered by rule-based machineries like term and graph rewriting. Realistic problems, however, call for suitable techniques to guarantee scalability. For instance, many domains exhibit a hierarchical structure that can be exploited conveniently. This is particularly evident for composition associations of models. We propose an explicit representation of such structured models and a methodology that exploits it for the description and analysis of model- and rule-based systems. The approach is presented in the framework of rewriting logic and its efficient implementation in the rewrite engine Maude and is illustrated with a case study.
Combining constructive and equational geometric constraint solving techniques
In the past few years, there has been a strong trend towards
developing parametric, computer aided design systems based on
geometric constraint solving. An efective way to capture the design
intent in these systems is to define relationships between geometric
and technological variables.
In general, geometric constraint solving including functional
relationships requires a general approach and appropiate techniques toachieve the expected functional capabilities.
This work reports on a hybrid method which combines two geometric
constraint solving techniques: Constructive and equational.
The hybrid solver has the capability of managing functional
relationships between dimension variables and variables representing
conditions external to the geometric problem.
The hybrid solver is described as a rewriting system and is shown to
be correct.Postprint (published version
Modelling IEEE 802.11 CSMA/CA RTS/CTS with stochastic bigraphs with sharing
Stochastic bigraphical reactive systems (SBRS) is a recent formalism for modelling systems that evolve
in time and space. However, the underlying spatial model is based on sets of trees and thus cannot represent
spatial locations that are shared among several entities in a simple or intuitive way. We adopt an extension of
the formalism, SBRS with sharing, in which the topology is modelled by a directed acyclic graph structure. We
give an overview of SBRS with sharing, we extend it with rule priorities, and then use it to develop a model
of the 802.11 CSMA/CA RTS/CTS protocol with exponential backoff, for an arbitrary network topology with
possibly overlapping signals. The model uses sharing to model overlapping connectedness areas, instantaneous
prioritised rules for deterministic computations, and stochastic rules with exponential reaction rates to model
constant and uniformly distributed timeouts and constant transmission times. Equivalence classes of model states
modulo instantaneous reactions yield states in a CTMC that can be analysed using the model checker PRISM.
We illustrate the model on a simple example wireless network with three overlapping signals and we present some
example quantitative properties
- …