Trusting an Information Agent

While the common kinds of uncertainties in databases e g null values disjunction corrupt missing data domain mis match etc have been extensively studied a relatively unexplored form of uncertainty in databases called inaccurate data demands due attention Inaccurate data results when data are contributed by various information agents with some known reliability Though the data itself is total or complete the reliability of the data now depends on the agent s reliability Several issues of this form of data reliability have been reported recently where the reliability of agents were assumed to be known and static In this paper we ad dress the issue of reliability maintenance of information agents and take the view that the agent reliability is dynamic and is a function of the database knowledge and the agent evidences facts that are observed to be true or false We propose a method of quantifying the level of trust or the agent reliability that the database sys tem should rest on the agent based on observation and statistical estimation