Extending Variable Importance in Preference Networks
Yannis Dimopoulos, Pavlos Moraı̈tis, Alexis Tsoukiàs · 2005
In many application domains we need to find so-lutions that satisfy, apart from a set of hard con-straints, a set of user defined preferences. Ce-teris Paribus (CP)-networks have been proposed as an intuitively appealing framework for expressing preference statements. CP-nets have been further extended to incorporate information on the relative importance of the variables, resulting in a formal-ism called TCP-nets. Despite their high expressive power, TCP-nets do not capture certain types of preference statements that seem to arise naturally in practice. In this paper we extend TCP-networks with vari-able importance statements that specify that a vari-able is more important than its ancestors in the net-work. These importance statements may induce preference relations on the set of outcomes that contain conflicting pairs. To handle such cases we propose a new semantics that aggregates preference and variable important information in such a way that preferences on more important variables over-ride preferences on less important variables. 1