Subject: Paper available

From: Bob Levinson <[email-masked]>
Date: Thu, 28 Apr 1994 12:41:42 -0700

The following paper is available anonymous ftp from ftp.cse.ucsc.edu
cd /pub/tr/ucsc-crl-94-15.ps.Z. Let me know if you have any trouble.

--Bob

[In particular it is described how the next version of Morph will
be domain-independent, store thousands more patterns and match
them at a fraction of previous cost. Forthcoming papers
will cover similar improvements to the learning mechanism.]

\title{\large\bf UDS: A Universal Data Structure}
\author{\large Robert Levinson}

\begin{abstract}   
This paper gives a data structure (UDS) for supporting database retrieval,
inference and machine learning that attempts
to unify and extend previous work in relational databases, semantic networks, conceptual graphs, RETE,
neural networks and case-based reasoning.  Foundational to this view is that all data can be viewed as a primitive set of objects and mathematical relations (as sets of tuples) over those objects.
The data is stored in three partially-ordered hierarchies:
a node hierarchy, a relation hierarchy, and a conceptual graphs hierarchy.
All three hierarchies can be stored as ``levels" in the
conceptual graphs hierarchy.
These multiple hierarchies support multiple views of the data with
advantages over any of the individual methods. In particular,
conceptual graphs are stored in a relation-based compact form
that facilitates matching.
UDS is currently being implemented in
the Peirce conceptual graphs workbench and is being used as a domain-independent
monitor for state-space search domains at a level that is faster
than previous implementations designed specifically for those 
domains.In addition it provides a useful environment for pattern-based
machine learning.
\end{abstract}

\section{Introduction}
Three popular and competing database paradigms are {\bf relational databases},
in which
data is stored and accessed as a set of tables, {\bf conceptual graphs}, in
which data is stored as a set of graphs, or {\bf semantic networks} in which
data is stored in one large homogeneous network(graph). In this paper we
give a data structure that can be seen to replace the others, with all
the advantages of each and fewer of the disadvantages.