Decision-Theoretic Planning for User-Adaptive Systems: Dealing With Multiple Goals and Resource Limitations

While there exists a number of user-adaptive systems that use decision-theoretic methods to make individual decisions, decision-theoretic planning has hardly been exploited in the context of useradaptive systems so far. This thesis focuses on the application of decision-theoretic planning in user-adaptive systems and demonstrates how competing goals and resource limitations of the user can be considered in such an approach. The approach is illustrated with examples from the following domains: user-adaptive assistance for operating a technical device, user-adaptive navigation recommendations in an airport scenario, and finally user-adaptive and location-aware shopping assistance. With the shopping assistant, we have analyzed usability issues of a system based on decision-theoretic planning in two user studies. We describe how hard time constraints, as they are induced, for example, by the boarding of the passenger in an airport navigation scenario, can be considered in a decision-theoretic approach. Moreover, we propose a hierarchical decision-theoretic planning approach based on goal priorization, which keeps the complexity of dealing with realistic problems tractable. Furthermore, we specify the general workflow for the development and application of Markov decision processes to be applied in user-adaptive systems, and we describe possibilities to enhance a user-adaptive system based on decision-theoretic planning by an explanation component

When policies are better than plans: Decision-theoretic planning of recommendation sequences

An intelligent user interface sometimes needs to present a sequence of related recommendations to a user, in spite of being uncertain in advance as to whether (and with what success) the user will follow each recommendation. There are potential advantages to the use of decision-theoretic planning methods which yield an optimal policy for the situationdependent presentation of recommendations. This approach is discussed with reference to an example involving route instructions given by an airport assistance system

User-Acceptance of a Decision-Theoretic Location-Aware Shopping Guide

We are exploring a class of decision-theoretic handheld systems that give a user personalized advice about how to explore an indoor area in search of products or information. An initial user test in a simple mockup of a shopping mall showed that even novice PDA users accepted the system immediately and were able to achieve their shopping goals faster than when using a paper map of the mall. A key issue is the extent to which spontaneous user behavior can be accommodated within this framework

User acceptance of a decision-theoretic location-aware shopping guide

We are exploring a class of decision-theoretic handheld systems that give a user personalized advice about how to explore an indoor area in search of products or information. An initial user test in a simple mockup of a shopping mall showed that even novice PDA users accepted the system immediately and were able to achieve their shopping goals faster than when using a paper map of the mall. A key issue is the extent to which spontaneous user behavior can be accommodated within this framework

Empirically Grounded Decision-Theoretic Adaptation to Situation-Dependent Resource Limitations

This article summarizes research on several interrelated general issues that can arise in the design and development of user modeling systems: the learning and subsequent adaptation of general user models on the basis of empirical data; the modeling of temporally variable properties of users, in particular time pressure and cognitive load; and the user-adaptive planning of interactions under uncertainty. The methods and results are integrated and illustrated with a prototype of a mobile assistance system for travelers in an airport