Research Topics

Active: 2013-2014

A Touch-based Mobile Ontology Browser

Jelly-Ont is a new ontology browsing application for Android.  Jelly-Ont exploits a layered architecture (Figure below) aimed at decoupling ontology access primitives from graph representation engines and from node-layout algorithms. At the lower layer, ontology access is handled by full-blown, well established ontology APIs such as Jena (see Apache Jena on Android), OWL API, etc. The ontology model exposed by such APIs is then abstracted into a shared graph representation, designed taking inspiration from the Prefuse Information Visualization toolkit architecture. This shared representation offers standard query primitives to layout algorithms, thus enabling them to get the information needed to successfully set-up an ontology visualization.

In the current Jelly-Ont implementation a RadialTree layout engine has been implemented by “porting” the corresponding Prefuse layout. The same operation can be done for other layouts either available in Prefuse or stemming from other sources, e.g., algorithms recently defined in literature [11,6]. Each layout engine can exploit custom-node renderers (node rendering modules reported in Figure 6) to assign a visual representation to the node positioned on the application viewport. Node renderers can be changed at runtime, thus enabling advanced interface building (implementing, for example, node overlays,
animations, etc.).

The actual implementation of Jelly-Ont maps the activities identified in the design process to real Android activities, and manages switching between them as defined in the workflow design. It targets an Android 4.x environment and has been tested on different platforms including: 3 Asus Transformer Pad (TF300T / TF300TG) tablets and 1 Samsung Galaxy Tab 10.1.