Proceedings of the 12th European Conference on Knowledge ...

Max Erik Rohde and David Sundaram
Strings, Booleans and Integers as well as complex composite objects) are adopted. Exhibit 1 shows a
simple graph specified in <strong>the</strong> domain specific language <strong>of</strong> <strong>the</strong> prototype:
Network n = Nx.newNetwork();
String primes = "A few prime numbers";
Nx.put().node(primes).inNetwork(n);
Nx.append().node(2).to(primes).inNetwork(n);
Nx.append().node(3).to(primes).inNetwork(n);
Exhibit 1: Definition <strong>of</strong> a simple graph
The created graph can easily be rendered into <strong>the</strong> semantic web format RDF, XML or end user
friendly HTML using <strong>the</strong> Jena Semantic Web Framework and XStream Framework. While many
technologies allow persisting data in graph-like structures, few <strong>of</strong> <strong>the</strong>se allow <strong>the</strong> flexibility <strong>of</strong> working
with generic objects as nodes <strong>of</strong> <strong>the</strong> network.
Design Challenge 2: Without strict data structures, structural parameters <strong>of</strong> knowledge
cannot be established
Guideline 2 suggests that a system should be able to consider both situational requirements as well
as possible structural parameters for knowledge work. The example above, for instance, could reflect
<strong>the</strong> situational requirement to specify a selection <strong>of</strong> prime numbers. The only structural parameter
embedded in <strong>the</strong> system is to adhere to a directed, unlabelled graph. However, if specifying prime
numbers were a recurring task, it would be desirable to specify restricting rules to assure <strong>the</strong> quality <strong>of</strong>
data added to <strong>the</strong> graph. For instance, it could be specified that only numbers or integers are valid
prime numbers. Such a rule can be specified with <strong>the</strong> domain specific language <strong>of</strong> <strong>the</strong> prototype as
follows:
Tree primesRule = Nx.defineTree().withRoot(primes)
.whichLinksTo(Nodes.only(Nx.instanceOf(Integer.class)));
Exhibit 2: Definition <strong>of</strong> simple syntactical rule
The initially created network can now be validated against this rule and any violation can be reported
to <strong>the</strong> user. Such syntactical rules can be gradually imposed on complex information in order to reflect
structural constraints in different degrees <strong>of</strong> severity. Although <strong>the</strong>re are a number <strong>of</strong> approaches to
validate data, most <strong>of</strong> <strong>the</strong>se focus on individual objects or two-dimensional data sets and few support
<strong>the</strong> specification <strong>of</strong> network-based rules.
Design Challenge 3: ‘Local’ personal information must be presented to <strong>the</strong> individual with
reduced complexity while still allowing access to ‘global’ organizational information
Guideline 3 suggests focusing on individuals as mediators <strong>of</strong> complex organizational knowledge
flows. Consequently, information must be presented in a form tailored to <strong>the</strong> individual while
remaining fully compatible with richer and more complex organizational repositories. To meet this
challenge, <strong>the</strong> prototype supports ‘local’ and ‘global’ networks, which can be woven toge<strong>the</strong>r into
customized networks using two-way synchronization. In <strong>the</strong> example below (Exhibit 3), <strong>the</strong> initial
‘prime number network’ is extended by adding a uniquely identified node numberRanges. This node
is <strong>the</strong>n added to a customized local user network as an address reference. This reference can be
resolved into <strong>the</strong> actual node residing in <strong>the</strong> global network by utilizing <strong>the</strong> network synchronization
mechanism <strong>of</strong> <strong>the</strong> prototype.
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