Towards a profile driven service authoring and adaptation platform

The modern telecom and Internet world is characterized by a whole plethora of devices which the user may use to access a given service. When confronted with such a richness of user devices, the traditional way of creating a service – i.e. writing separate code for each type of user device– no longer seems appropriate. A more sophisticated approach is called for in order to facilitate the implementation of "any service, any time, any place" scenarios. The development of device independent authoring tools will be crucial in this context.

In recent years XML-based technologies have gained a widespread acceptance as they opened up a whole avenue for creating and managing telecom and Internet services. Well-known examples of XML languages comprise XHTML for use in standard PC’s, WML for WAP GSM’s and VoiceXML for voice enabled devices (such as ordinary phones). Each of these languages was designed with a limited set of devices in mind. Therefore, it is difficult (if not impossible) to select one of these languages and use it as a basis for a device independent authoring. Instead we propose to build a new XML language that from the outset takes into account the following design principles:

• It should allow for "author-once deploy-many" scenarios
• It should achieve a clean separation between the behavior, content and presentation of the service.
• It should contain support for automatic adaptation and personalization of the service.

Below we will outline our vision on new ways to create adaptive information and communication services in a highly efficient manner. This vision is based on (i) the use of XML as enabler to separate the service’s data model, its presentational and behavioral components and (ii) a unified RDF-based profile framework (describing user, terminal, service, etc.) which will drive the adaptation process.

1.- The Abstract User Interface Language

We have started the design of a device-independent XML language. This language is called the Abstract User Interface markup Language (AUIL) and it forms the basis of the "service authoring and adaptation platform". The idea is to describe the generic properties of a given interactive voice or information service with the Abstract User Interface markup Language, and then automatically adapt the service content, behavior and presentation towards the various device-specific XML languages (XHTML, WML, VoiceXML etc.). The service adaptation process will be based on the user’s preferences, his terminal capabilities, his current location, the service requirements etc.

The Abstract User Interface Language consists of three types of elements.

• First there are core AUIL elements. AUIL is designed for authoring a "skeleton service", which mainly concentrates on the behavioral aspect of the service. In particular a service is divided into several "units", which describe separate dialogs between the user and the service (forms, menus…). The description of the service workflow also includes event handling and the use of variable-value pairs. AUIL documents may contain explicit content as well, but in view of the desired separation of behavior, content and presentation the explicit content in AUIL documents should be kept minimal. AUIL contains no (or at least very little) support for presentation. Presentation should be dealt with by applying style sheets.
  Core AUIL elements are subject to device-specific but service-independent XSLT transformations. These XSLT transformations define a mapping from the core AUIL elements to e.g. WML, VoiceXML or XHTML elements. On the result of the first XSLT transformation a second service-dependent style sheet may be applied as well, in order to further determine the look and feel of the service.
• AUIL elements that provide support for run-time retrieval of profile information. The profile tags must be processed by the service authoring and adaptation framework. In particular, profile information may influence the service workflow and may determine which content will be rendered to the user.
• AUIL elements that allow retrieving of dynamic content, for instance from third party content providers. A JSP-like technique probably will be useful here.

2.- From profiles to personalized services

Today’s service providers have to take into account the various wishes and needs of their end-users. These are usually captured in user preference profiles and have a strong relation with the service configuration. The user preferences are also constrained by the capabilities of the device used to interact with the network: limited display, reduced amounts of memory, sporadic connections with a high latency and low bandwidth are typical characteristics of most common personal devices such as GSMs .

An effective service adaptation process should rely on a complete and just-in-time acquisition of all service delivery parameters, which is not an easy requirement. First of all, knowledge about terminal features, network speed, location information, user preferences etc. is often spread over the network, as different parties own their own types of information. Secondly, some information will be quite static (e.g. the user’s name) while others may be very dynamic in nature (the user’s location).

We propose to use the power of RDF to express profiles, combined with well-chosen algorithms for advanced querying and matching, thus allowing the adaptation of the service in a non-trivial provisioning context.

Based on a detailed study of standards from different bodies including W3C, IETF, ETSI and OMG, we have recently defined several types of profiles that are relevant to the service-provisioning context. This has resulted in a "Unified Profile Scheme", consisting of the following profile components:

• The Terminal profile describes all terminal capabilities and characteristics.
• The User profile describes various types of information related to an 'economic entity' (a person or an organization).
• The Service profile describes a service, offered to a certain economic entity by another economic entity.
• The Preferences/Interest profile describes all 'personal' preferences/interests of a certain economic entity. A preference is a kind of (implicit) rating on something, e.g. an interest.
• The Location profile describes the presence of a certain terminal or other object. This includes also descriptions of routes from one location to another (which can be useful to anticipate some events or user interests).
• The Network profile describes the network that the terminal of the economic entity uses to get a certain service

3.- Implementation

At present we are implementing the various building blocks of the service authoring and adaptation platform. These consist of

• an authoring environment for voice and information services based on the Abstract User Interface Language
• an application server hosting various types of adaptation servlets, which support amongst others XSLT style-sheeting and dynamic content generation mechanisms.
• profile servers, supporting a newly developed RDF-based profile management protocol, taking into account the distributed nature (both in time and space dimensions) of profiles.

References

1. "Extensible Markup Language (XML) 1.0", W3C Recommendation 10 February 1998, http://www.w3.org/TR/1998/REC-xml-19980210
2. "XHTML 1.0: The Extensible HyperText Markup Language", W3C Recommendation 26 January 2000, http://www.w3.org/TR/xhtml1
3. "HTML 4.01 Specification", W3C Recommendation, 24 December 1999, D. Raggett, A. Le Hors, I. Jacobs, on-line at http://www.w3.org/TR/1999/REC-html401-19991224
4. "Voice eXtensible Markup Language (VoiceXML™) version 1.0", W3C Note 05 May 2000, http://www.w3.org/TR/voicexml/
5. "Wireless Markup Language Specification, version 1.3", 19 February 2000 http://www1.wapforum.org/tech/terms.asp?doc=WAP-191-WML-20000219-a.pdf
6. "Resource Description Framework (RDF) Model and Syntax Specification", W3C Recommendation, 22 February 1999, on-line at http://www.w3.org/TR/REC-rdf-syntax/
7. The World Wide Web Consortium (W3C), http://www.w3.org/
8. IETF: The Internet Engineering Task Force, http://www.ietf.org/
9. ETSI: The European Telecommunications Standards Institute, http://www.etsi.org/
10. The Object Management Group (OMG), http://www.omg.org/