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\begin{document}

\title{Structural Computing and Metadata Management}

\author{{\bfseries Anna Musterfrau}\\
   (Graz University of Technology\\
   anna.musterfrau@example.at)
   \and
   {\bfseries Max Mustermann}\\
   (Example University, Example Country \\
   max.mustermann@example.at)\\
}
\maketitle

\begin{abstract}
A short and pregnant description of the content and intent of the article. Please try to avoid mathematical symbols and special characters as much as possible.
\end{abstract}

\begin{keywords}
metadata, knowledge management, structural computing
\end{keywords}

\begin{category}
H.2, H.3.7, H.5.4 
\end{category}

\section{Introduction}

In this paper, we begin by introducing ...

\section{Structural computing}

\subsection{History}

Hypermedia has become a concept familiar to many people ... The term
\emph{structural computing} was coined to describe this unification of
various hypermedia variants within a common framework \cite{sc}.

\subsection{Comparing data- and structure-based approaches}

Structural computing environments are distinguished by their focus on
the construction and management of structural abstractions ...

This realization significantly complicates certain otherwise
well-understood problems....  

Similar examples of structural complications in version control and
access control have been discussed at length within the hypermedia and
structural computing communities (e.g., \cite{tois-ver, hoss}).


\subsection{Current status}

There is much ongoing work within the structural computing field (see,
for example, the proceedings of the last three workshops on structural
computing \cite{sc2-proc, sc1-proc, sc3-proc}).  Two modern structural
computing systems are Callimachus \cite{callimachus} and Construct
\cite{construct}....  It is a codebase
successor to three lines of hypermedia research systems --
specifically, DHM \cite{dhm}, HOSS \cite{hoss}, and HyperDisco
\cite{hyperdisco}.  Both the Callimachus and Construct systems
implement a wide variety of structural services.  Recently, a metadata
service, allowing the tagging of WWW pages with arbitrary metadata
records, has been added to Construct \cite{construct-md}.

\section{Metadata as first-class structure}

Metadata is not simply data ...

Secondly, a given metadatum may be related to more than one datum.
For example, two data that share identical authors may both be related
to an identical author metadatum.  This ``transclusion'' \cite{nelson}
model of building metadata references is atypical -- generally, two
metadata records for data that share identical authors simple both
share, for example, identical text in an author key field.  At one
level of abstraction (e.g., the user interface), this model of
metadata may be useful -- a metadata browser may want that matadata
presented as keyword/value pairs.  However, from an implementation
perspective, the keyword/value pair model is a poor choice.  It makes
several types of operations, such as updating information (e.g.,
``change all instances of \emph{Joe Public} to \emph{Joe
Q. Public}''), querying for related information (e.g., ``find all
articles authored by \emph{Joe Q. Public}''), or differentiating
information (e.g., ``which of the three authors named \emph{Joe
Q. Public} authored this article?'')  unnecessarily difficult...  

\section{Generalized first-class metadata management}

In this section, we present some brief examples of how implementing
metadata management ...The implementation and implications of such
examples are described at greater length elsewhere (e.g.,
\cite{tois-ver, hoss}).

\subsection{Data mining}

If metadata are treated as structure ...

\subsection{Adaptive systems}

When structures (both metadata itself, and the structure that binds it
to data) are treated as first-class, they may then be manipulated as
any data object, including being tagged ith attriubute/value pairs and
being versioned.  Both of these characteristics are very useful in
adaptive systems \cite{adapt}...



\section{Conclusions and Future Work}

Until recently, focus in metadata research has focused on what
metadata is and how it should be represented to the user.  However,
there has been a lack of focus on how it should be managed at a system
level.  We have shown that treating metadata as simple data out of the
context of the relationships to which it belongs, and which it
defines, although the current default model, is insufficient.  We
advocate borrowing structure management techniques from fields such as
structural computing to manage metadata more effectively.

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\end{thebibliography}

\end{document}
