Databases Reference
In-Depth Information
2.4
Other Requirements
As digitald documents are frequently shared and accessed through networks by
many users, their contents have to be prepared to satisfy requirements of many
users such as interests and levels For example, some user might want only a specific
topic with explanation for novices and his friends' memos. In such cases, necessary
contents shaould be dynamically extracted from the shared document. As such
multifold information cannot be obtained by conventional information retrieval
technologies, multifold information has to be embedded inside digital documents.
As digital documents are esssntially multimedia-based, we can apply this
application to others such as digital theme parks. In such an application, we require
additional extensions according to specific domains.
3
Extensions of XML for Multimedia Document
3.1
Graph Framework of XML
First, consider a simple example of XML in Figure 1. Although there are many
Figure 1: Example of XML
approches to formalization of XML, we consider an XML document as a graph
with labeled edges or a set of graph equations. Figure 1 is represented as a graph
with labeled edges as in Figure 2.
Figure 2 can be represented as a set of graph equations as in Figure 3, where
“_” is an anonymous variable or a dummy value.
Although this definition might be redundant, it is very useful to define special
attributes such as constructors, for example, into
of the above example. In
Abiteboul et al 99)
, ssd-expression for representing semi-structured data is defined.
goods
