臺大管理論叢 NTU Management Review VOL.28 NO.3

89 NTU Management Review Vol. 28 No. 3 Dec. 2018 document recommendation effectiveness and improve the user experience. The spreading activation model comprises a spreading activation network and an activation spreading mechanism. The spreading activation network is similar to the semantic network which is made up of a set of nodes and links. A node in the network represents a concept, and a link represents the semantic relationship between two concepts (Crestani, 1997). The activation spreading mechanism is a diffusion process among nodes, and is controlled by two actions: pulse spreading and a termination check. A pulse continuously spreads from one node to the surrounding nodes controlled by input and output value adjustments which constrain the spreading range and spreading weight. The termination check is used to verify whether the conditions for termination have been met (Liang et al., 2008). As shown in Figure 1, the overall process of the ICE technique is accomplished in three phases: user preference assessment, document concept expansion, and document recommendation. The purpose of the user preference assessment phase is to identify the documents of interest by considering both the time the focal user spent browsing the documents and the user’s preliminary feedback regarding document preferences. The document concept expansion phase is to expand the concepts existing in the documents of interest by the spreading activation model. In the document recommendation phase, each document is evaluated, and the top- k documents that involve more concepts relevant to the focal user’s interests are recommended. We model these phases of the ICE technique as follows: Figure 1 Overall Process of the ICE Technique Targeted User's Preference Profile Targeted User's Browsing Behavior Domain Concept Heterarchy Documents with Known Concepts User Preference Assessment Document Concept Expansion Document Recommendation