Fault-tolerance is an important issue in network design because sensor networks must function in a dynamic, uncertain world. In this paper, we propose a functional characterization of the fault-tolerant integration of abstract interval estimates. This model provides a test bed for a general framework which we hope to develop to address the general problem of fault-tolerant integration of abstract sensor estimates. We further propose a scheme for narrowing the width of the sensor output in a specific failure model and give it a functional representation. The main distinguishing feature of our model over the original Marzullo's model is in reducing the width of the output interval estimate significantly in most cases where the number of sensors involved is large.
