PyGraph: a graphic front-end for the PAISLey executable specification language

This project is an application software system providing a graphical interface to PAISLey. PAlSLey (Process Oriented. Applicative. Interpretable Specification Language) is an executable specification language developed at AT&T Bell Labs to model real-time systems. The interface provides the user with a tool to graphically depict a real-time system. The graphics package, called PyGraph, has been implemented on a Sun 3 in a multi-window environment. While developing a graphic, PyGraph generates a PAISLey specification template for the graphic image. The template is filled out by the user with assistance provided by PyGraph

A Semantics for Timed MSC

AbstractMessage Sequence Charts (MSC) is a graphical and textual specification language developed by ITU-T. It is widely used in telecommunication software engineering for specifying behavioral scenarios. Recently, the time concept has been introduced into MSC'2000. To support the specification and verification of real-time systems using timed MSC, we need to define its formal semantics. In this paper, we use timed lposet as a semantic model and give a formal semantics for timed MSC. We first define an event in a timed MSC as a timed lposet, then give a formal semantics for timed basic MSCs, timed MSCs with structures and high-level MSCs. In this paper, we also discuss some important issues related to timed MSC

Bounded repairability for regular tree languages

International audienceWe consider the problem of repairing unranked trees (e.g., XML documents) satisfying a given restriction specification R (e.g., a DTD) into unranked trees satisfying a given target specification T. Specifically, we focus on the question of whether one can get from any tree in a regular language R to some tree in another regular language T with a finite, uniformly bounded, number of edit operations (i.e., deletions and insertions of nodes). We give effective characterizations of the pairs of specifications R and T for which such a uniform bound exists, and we study the complexity of the problem under different representations of the regular tree languages (e.g., non-deterministic stepwise automata, deterministic stepwise automata, DTDs). Finally, we point out some connections with the analogous problem for regular languages of words

Mapping SDL Specification Fundamentals to Core SDL Ontology

This paper gives a contribution in the efforts of Semantic web ontology development. We have developed the core ontology for Specification and Description Language (SDL),an object-oriented, formal language defined by the International Telecommunications Union Telecommunications Standardization Sector (ITU-T) as recommendation Z.100. The language is intended for the specification of complex, event-driven, real-time, and interactive applications involving many concurrent activitiesthat communicate using discrete signals. Using SDL formal model for system specification we bridge the gap between ideas in our minds and the actual implementation of the system. Being visually appealing SDL provides us with a simple tool for communication either between the softwaredevelopers or between non-experts without advanced engineering skills. In this paper we propose the ontology for the basic SDL system and process elements. We also propose a formal framework of SDL Markup Language as a medium for translating SDL model to SDL ontology

Ravenscar computational model compliant AADL simulation on LEON2

AADL has been proposed for designing and analyzing SW and HW architectures for real-time mission-critical embedded systems. Although the Behavioral Annex improves its simulation semantics, AADL is a language for analyzing architectures and not for simulating them. AADS-T is an AADL simulation tool that supports the performance analysis of the AADL specification throughout the refinement process from the initial system architecture until the complete, detailed application and execution platform are developed. In this way, AADS-T enables the verification of the initial timing constraints during the complete design process. In this paper we focus on the compatibility of AADS-T with the Ravenscar Computational Model (RCM) as part of the TASTE toolset. Its flexibility enables AADS-T to support different processors. In this work we have focused on performing the simulation on a LEON2 processor.This work has been supported by ESTEC 22810/09/NL/JK HW-SW CODESIGN Project contracted to GMV Aerospace and Defence S.A.U

PTE: Axiomatic Semantics based Compiler Testing

The correctness of a compiler affects the correctness of every program written in the language, and thus must be thoroughly evaluated. Existing automatic compiler testing methods however either rely on weak oracles (e.g., a program behaves the same if only dead code is modified), or require substantial initial effort (e.g., having a complete operational language semantics). While the former prevents a comprehensive correctness evaluation, the latter makes those methods irrelevant in practice. In this work, we propose an axiomatic semantics based approach for testing compilers, called PTE. The idea is to incrementally develop a set of ``axioms'' capturing anecdotes of the language semantics in the form of \emph{(\textbf{p}recondition, \textbf{t}ransformation, \textbf{e}xpectation) triples, which allows us to test the compiler automatically.} Such axioms are written in the same language whose compiler is under test, and can be developed either based on the language specification, or by generalizing the bug reports. PTE has been applied to a newly developed compiler (i.e., Cangjie) and a mature compiler (i.e., Java), and successfully identified 42 implementation bugs and 9 potential language design issues

The corpus of the Danish dictionary

A Danish corpus, holding 40 million words of general language from the period 1983-92, was designed and compiled by DSL (The Society for Danish Language and Literature) in order to serve as a major source for a new six volume dictionary of contemporary Danish. The corpus includes written and spoken, private and professional, general and specialised language, and each of the 44 000 text samples is annotated with formalized information on these and other features of linguistic and sociological importance. The resulting multidimensional text type specification is useful for the extraction of (virtual or real) subcorpora and for statistical analyses. Specialized software has been developed for flexible interactive concordancing and analysis. The corpus is currently only accessible at the site of DSL; nevertheless, several scholars and students have been using it in their research. The experience gained by the staff of DSL is being reused in co-operative language engineering projects within the European Union, and in 1998 a publicly available corpus will be released as an outcome of the PAROLE project.  Keywords: concordance; copyright; corpus; danish; dictionary; frequency; language engineering; mutual information; sgml; statistics; subcorpus; t-score; text typology; word distributio

Using Scriptit.py to Define MB_CNS Simulations: A Reference for the Flow-Description Python Modules

A flow simulation is set up by first describing the flow domain as one or more blocks of finite-volume cells and specifying both initial and boundary conditions. The simulation then proceeds in a number of stages: (1) start with the input script and prepare the block grids and initial (i.e. t = 0) flow solution; (2) run the simulation to produce snapshots of the flow solution at one or more subsequent times; and (3) postprocess the accumulated flow solution data to extract particular data that may be of interest. The input script is written in the Python programming language and, when executed by the scriptit program, it creates various geometric and flow-condition objects as needed. This report describes the set of classes and functions that are available for creating the flow specification. Of course, the rest of the Python language is also available and may be used to assist (or automate) the set-up calculations