Using Synchronised Tag Clouds for Browsing Data Collections - Advanced Information Systems Engineering - page 216

would show only the keywords associated with CAiSE papers and the Confer-
ences cloud would show only CAiSE .
Presenting single items in one of the tag clouds is useful in terms of showing
the context in which the other tag clouds should be interpreted. However, once
a tag has been selected there are no further selections possible in that cloud
and this is one of the limitations of using tag clouds that we alluded to before
when we stated that they can only support simple, single step searches. To
support further filtering of Conferences based on other properties, an application
developer could specify alternative tag clouds for that data collection and these
would be available through a dropdown menu. As illustrated in Fig. 2, we also
offer a tag cloud for Conferences showing the year of conference as well as one
showing the title instead of keywords for Publications .
Fig. 2. Browsing example
For users to keep track of the selections they have made while browsing the
database, we show the navigation path in terms of the tags that have been
selected from the tag clouds at the top of the browser. In the example of Fig. 2,
the user has first selected the CAiSE conference and the keyword Web before
switching to an alternative view for Conferences to select the year 2010 .The
user has then also switched the Publications view to show the titles instead
of the keywords of the resulting three publications. Users can use this kind of
breadcrumb navigation to go one or more steps back in the sequence of tag
selections or click on Al l to return to the initial browser view shown in Fig. 1.
For each tag cloud, the items resulting from the filtering process are visualised
in the designated areas beneath the respective tag cloud if the number of results
does not exceed a certain threshold also defined by the application developer. A
user can view these items by simply clicking on them. In the case of the Authors
tag cloud, the author information of a specific author can be accessed. For the
Publications cloud, publications can be accessed as PDF files and, in the case of
the Conferences cloud, the conference proceedings can be viewed.
We offer different visualisations for tag clouds so that the developer may
choose one appropriate to the information to be displayed and even the task at