Joey Paquet

Towards an ASSL specification model for NASA swarm-based exploration missions

NASA swarm-based exploration missions represent a new class of concept missions based on the cooperative nature of a hive culture. A mission of this class requires an autonomic system, comprising a set of autonomous mobile units. The design and implementation of such systems requires specific engineering approaches, including new formal specification methods and techniques. This article presents an introduction to our research towards a formal specification of NASA concept swarm-based missions. The Autonomic System Specification Language (ASSL) is a framework for formally specifying and generating autonomic systems. With ASSL, we can specify high-level behavior policies, as part of overall system behavior, which shows that ASSL is a very appropriate language for specifying the autonomic behavior of swarm-based missions. We show how ASSL can be used to specify self-configuring, self-healing, and safety properties of NASA swarm-based missions.

The GIPSY Architecture

Intensional Programming involves the programming of expressions placed in an inherent multidimensional context space. It is an emerging and highly dynamic domain of general application. The fast growing computer connectivity allows for more and more efficient implementation of distributed applications. The paradigm of intensionality inherently includes notions of parallelism at different levels. However, the currently available intensional programming software tools are becoming obsolete and do not enable us to further push forward practical investigations on the subject. Experience shows that the theoretical advancement of the field has come to acceptable maturity. Consequently, new powerful tools for intensional programming are required. In this paper, we present the design of a General Intensional Programming System (GIPSY). The design and implementation of the GIPSY reflect three main goals: generality, adaptability and efficiency.

ASSL - Autonomic System Specification Language

This article is an overview of the Autonomic System Specification Language (ASSL). ASSL is a framework for formally specifying and generating autonomic systems. The latter are specified as formal executable models with an interaction protocol and autonomic elements. We explain in detail the architecture of the ASSL framework and demonstrate how to specify autonomic systems. In this paper, we do not talk about syntax and semantic aspects of ASSL, since these are going to be tackled by our ongoing research and described in other papers.

Design and Implementation of Context Calculus in the GIPSY Environment

GIPSY is a platform providing a framework for the compilation and execution of programs written in intensional programming languages of the Lucid family. While maintaining its use of intensionality, over the years, Lucid constantly underwent changes in its syntax, and its semantics is getting more and more generalized. Throughout this hectic evolution of the language, various systems for the evaluation of Lucid programs were developed. Due to lack of ability to adapt to the syntax and semantic changes of the language, all of them met with doom as new evolutions of the language were proposed. Set in this evolutionary aspect of Lucid, GIPSY aims at easing the development of the Lucid family of intensional programming languages by providing a common system into which variants of Lucid can be compiled and executed and, more interestingly, developed in the future. One of the latest evolutions of Lucid is the language Lucx, permitting the explicit use of contexts as first-class atomic entities. This paper presents the integration of Lucxs context calculus into GIPSY. We define the notion of context according to Lucx, its syntax and semantics, as well as operators on such contexts. We then present how context entities have been abstracted into implementation classes and embedded into GIPSY.

Distributed Eductive Execution of Hybrid Intensional Programs

The GIPSY project is an ongoing effort aiming at providing a flexible platform for the investigation on the intensional programming model as realized by the latest versions of the Lucid programming language. The GIPSY provides an integrated framework for executing programs written in all variants of Lucid. This paper discusses our architectural framework for the run-time system that enables the distributed execution of such programs following the eductive model of computation.

Advances in the Design and Implementation of a Multi-tier Architecture in the GIPSY Environment with Java

We present advances in the software engineering design and implementation of the multi-tier run-time system for the General Intensional Programming System (GIPSY) by further unifying the distributed technologies used to implement the Demand Migration Framework (DMF) in order to streamline distributed execution of hybrid intensional-imperative programs using Java.

Using the General Intensional Programming System (GIPSY) for Evaluation of Higher-Order Intensional Logic (HOIL) Expressions

The General Intensional Programming System (GIPSY) has been built around the Lucid family of intensional programming languages that rely on the higher-order intensional logic (HOIL) to provide context-oriented multidimensional reasoning of intensional expressions. HOIL combines functional programming with various intensional logics to allow explicit context expressions to be evaluated as first-class values that can be passed as parameters to functions and return as results with an appropriate set of operators defined on contexts. GIPSYs frameworks are implemented in Java as a collection of replaceable components for the compilers of various Lucid dialects and the demand-driven eductive evaluation engine that can run distributively. GIPSY provides support for hybrid programming models that couple intensional and imperative languages for a variety of needs. Explicit context expressions limit the scope of evaluation of math expressions (effectively a Lucid program is a mathematics or physics expression constrained by the context) in tensor physics, regular math in multiple dimensions, etc., and for cyberforensic reasoning as one of the use-cases of interest. Thus, GIPSY is a support testbed for HOIL-based languages some of which enable such reasoning, as in formal cyberforensic case analysis with event reconstruction. In this paper we discuss the GIPSY architecture, its evaluation engine and example use-cases.

A type system for hybrid intensional-imperative programming support in GIPSY

We describe a type system for a platform called the General Intensional Programming System (GIPSY), designed to support intensional programming languages built upon intensional logic and their imperative counter-parts for the intensional execution model. In GIPSY, the type system glues the static and dynamic typing between intensional and imperative languages in its compiler and runtime environments to support the intensional evaluation of expressions written in various dialects of the intensional programming language Lucid. The intensionality makes expressions to explicitly take into the account a multidimensional context of evaluation with the context being a first-class value that serves a number of applications that need the notion of context to proceed. We describe and discuss the properties of such a type system as well as particularities of the design and implementation of it.

An architecture for developing context-aware systems

This paper proposes a component-based architecture and development methodology for context-aware systems. A context is formally defined from relational point of view. The architecture of a context-aware system is conceived as a composition of the two components context constructor and context adapter. To process dynamically changing contextual information, we introduce context calculus as the formal basis of context manipulation. The information and its sources are abstracted within this formal definition. As an illustration of the principles involved in developing a context-aware system, we discuss the Anti-lock Braking System problem.

Object-Oriented Intensional Programming: Intensional Java/Lucid Classes

This article introduces Object-Oriented Intensional Programming (OO-IP), a new hybrid language between Object-Oriented and Intensional Programming Languages in the sense of the latest evolutions of Lucid. This new hybrid language - called JOOIP for Java Object Oriented Intensional Programming - combines the essential characteristics of Lucid and Java, and introduces the notion of object streams which makes it is possible that each element in a Lucid stream to be an object with embedded intensional properties. Interestingly, this hybrid language also brings to Java objects the power to explicitly express and manipulate the notion of context, creating the novel concept of intensional object, i.e. objects whose evaluation is context-dependent, which are demonstrated to be translatable into standard objects.