Research and Advances
Computing Applications The adaptive web

Putting Personalization Into Practice

The N24 Web site [6] belongs to a network of sites operated by Kirch Group that complement associated television stations in Germany. The relaunch of the N24 site focuses on tighter integration with the N24 cable news brand, targeting managers in need of accurate real-time information delivery in the areas of investing, business, politics, and sports. The goals of personalization [5] include creating a one-to-one relationship with existing customers; providing direct access to personally relevant news; seamlessly integrating with the existing infrastructure, including content and its classification; and collecting information about user interests for driving cross-channel customer relationship management (CRM) activities.

From the perspective of a registered user, the N24 site offers a "My News" section on the N24 home page (see Figure 1) that provides a personalized selection of "Top Five" news headlines with direct links to the respective full-text versions of news items. This news selection is dynamically updated in real time as users interact with the N24 site.
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Personalization is managed by the humanIT Dynamic Personalization Server (DPS) [4], an open, standards-based, and platform-independent tool that provides essential user-modeling services to user-adaptive applications (see Figure 2). To produce the personalized list of top news, the publishing system queries the DPS Directory Component for a customer’s (presumed) interests. It uses the DPS response to in turn query the content management system and news database for relevant news items that match the interest profile returned by the DPS.

Whereas previous user-modeling systems stored data about users in database and knowledge representation systems [1, 2], DPS employs a Lightweight Directory Access Protocol (LDAP)-based directory management system [3]. This offers significant advantages with respect to the:

  • Management and retrieval of (user-related) information, which is compliant with widely established standards allowing for easy integration.
  • Addition of new information types to the set of predefined types, which allows for flexibility as sites and personalization goals evolve.
  • Distribution of information across a network leading to better performance, scalability, availability, and reliability.
  • Provision of facilities for authentication, signing, encryption, access control, auditing, and resource control for ensuring information security and users’ privacy.

The user profile acquisition process is implicit except for the initial registration. The system reports selected interaction events, enriched by content information, to the DPS. Different interaction types (for example, viewing the headline versus requesting the full text of a news item) carry different weights.

The DPS Directory Component stores user profiles as nodes in an LDAP directory, making the representation explicit and human-readable. User profiles can be inspected and/or modified via a browser interface and exported for analysis purposes or used as input to operative CRM applications.

The DPS component integrates multiple learning components that continuously process incoming event information in the background. The user-learning component determines and tracks particular interests of individual users over the time span of multiple sessions. The collaborative filtering component determines a “peer group” for each user based on user-interest profiles that are most similar to the profile of a particular user. This data can be used efficiently to predict the likelihood that a user is interested in a certain topic in cases where no prediction can be made based on the user’s individual interaction record. By integrating these techniques into a single server, we can leverage several synergistic effects between these techniques and compensate for their well-known deficits with regard to performance, scalability, integration of domain knowledge, and sparsity of data.

The humanIT personalization solution for N24 can be deployed in a wide range of e-business scenarios. The only requirements are a content management system offering classified content and a site’s ability to track individual customers.

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F1 Figure 1. The personalized N24 news Web site [

F2 Figure 2. The humanIT Dynamic Personalization Server (DPS) architecture.

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    1. Fink, J. User Modeling Servers: Requirements, Design, and Implementation. Ph.D. dissertation, Dept. of Mathematics and Computer Science, University of Essen, Germany, 2002 (forthcoming).

    2. Fink, J., and Kobsa, A. A review and analysis of commercial user modeling servers for personalization on the World Wide Web. User Modeling and User-Adapted Interaction 10, 2–3 (2000), 209–249.

    3. Howes, T., Smith, M., and Good, G. Understanding and Deploying LDAP Directory Services. Macmillan, Indianapolis, 1999.

    4. humanIT Dynamic Personalization Server (2002);

    5. Kobsa, A., Koenemann, J., and Pohl, W. Personalized hypermedia presentation techniques for improving customer relationships. The Knowledge Engineering Review 16, 2 (2001), 111–155.

    6. N24 Online (2002); (in German).

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