An implementation of the calibrating database in
"Georges Gardarin, Fei Sha, and Zhao-Hui Tang. 1996. Calibrating the Query Optimizer Cost Model of IRO-DB, an Object-Oriented Federated Database System. In Proceedings of the 22th International Conference on Very Large Data Bases (VLDB '96), T. M. Vijayaraman, Alejandro P. Buchmann, C. Mohan, and Nandlal L. Sarda (Eds.). Morgan Kaufmann Publishers Inc., San Francisco, CA, USA, 378-389."