TITLE: Tool and Information Management in Engineering
AUTHOR: Mark Thomas
PUBLICATION: Ph.D. Thesis, Carnegie Mellon University
DATE: 1996

ABSTRACT: As workstations and the network which connects them have
become more powerful, the information available to engineers has
become enormous. This research discusses the problems engineers
encounter in managing this information, in collaborating with other
engineers, and in integrating and using suites of computer-based
tools.

We introduce a computer environment, called n-dim, which supports
information management and collaboration; n-dim accomplishes this by
having a flat space of persistent objects over which the end user can
build structures, called models, and can describe these models by
creating grammars, called modeling languages. n-dim also
supports the maintenance of the history of these collaborative
processes.

The author has had a significant role in the implementation of many of
the n-dim objects and the methods which manipulate them; he also
describes how, through the implementation of special modeling
languages (namely GlassBox, Prescription, and Pattern), n-dim can
support the user in managing history through revision management, in
controlling access to the user's models, in adding attributes to
models, and in creating arrays.

After discussing n-dim, we describe the various levels at which one
can integrate tools into the n-dim environment, and we detail the
author's integration of a complex, interactive tool, the $ascend_link
system. ASCEND is an equation-based modeling environment to aid users
in creating, coding, debugging, and solving quantitative models
containing algebraic and differential equations. The goal was to
integrate this tool to aid using it for its primary purpose: to create
correctly formulated equation-based models. Like many compilers such
as those for C and Fortran, ASCEND is an instance of the class of
tools that support command line input, that construct instances (e.g.,
compiled programs) from the typical user input to them, and for which
access to the parts of those instances is useful within the n-dim
environment.

We conclude by arguing that integrating ASCEND within n-dim, with its
support for collaboration and history maintenance, give us most of the
properties that Geoffrion states modern modeling support systems
should have.