Building a semantic ontology for virtual peers in narrative-based environments

Narrative-based environments utilize various forms of knowledge to provide an interactive space for the learner and the virtual agent to collaborate in accomplishing the learning goals. In this paper, we present the design of a semantic ontology that provides the necessary domain-based conceptual knowledge to allow a virtual peer to engage in storytelling as a form of exchange with the learner. We then show how the ontology was utilized to support the virtual peer in performing its tasks, which include generating interactive stories that teach about appropriate social behavior, and engaging in a text-based dialogue with the learner. © Springer International Publishing AG 2017

Physics Study of EC-Excited Current Generation via Current Jump in the Compact Plasma-Wall-Interaction Experimental Device

"Non-inductive current start-up experiments by using electron cyclotron heating and current drive (ECH/ECCD) technique has been conducted in the Compact Plasma-wall-interaction experimental Device (CPD), which is a small spherical tokamak device. By applying 8.2 GHz RF under steady external fields, plasma currents are generated and closed flux surface configurations are formed spontaneously. Two discharge modes are found. The first one is the “current jump” discharge, in which the closed flux configuration is formed via the rapid increase of the plasma current under relatively high vertical magnetic field. The second one is a slow current increase discharge under lower vertical field, in which the closed flux surfaces are formed during a slow current increase with the slow increase of microwave power. Since the higher plasma currents under higher vertical fields can be obtained only via the current jumps, the current jump phenomena seems to be essential for the non-inductive start-up scenario based on ECH/ECCD technique. By comparing the co-directional O-mode injection and the normal X-mode injection in the current jump discharges, the current jump occurred at lower RF power in the co-directional O-mode than that in the normal X-mode. However, the values of plasma current just before and after current jumps did not depend on the injection mode.