ABSTRACT
ABSTRACT: The model of a water distribution network is a set of equations with parameters used in many tasks in water management. Such model needs to be calibrated to update the parameter values. Ormsbee and Lingireddy describe the calibration task (Omersbee 1997). The water distribution system must be represented by node-link database (links represent individual pipe sections, and nodes represent points in the system where two or more pipes join or where water is being input or withdrawn). The measurements are not ideal, the estimation-calibration problem is then formulated as a problem of minimising a suitably chosen measure of the inconsistencies in the microcalibration stage. In this paper the microcalibration stage is treated. The optimisation problem is characterised. A classification of optimisation problems and algorithms help to fix the kind of algorithms that can assure a good result. Three Global Optimisation Algorithms have been used. All three based on deterministic search using branch and bound. One takes advantage of the signomial formulation of the problem (Falk 1973). The second is the algorithm DIRECT based on lipsichtz properties of the function (Holmström 1998), the one that has given best results in time consume and robustness. The third uses intervalar arithmetic to bind the function (Kearfott 1996), in this case the software problems seem to be the limitation for its application. Small examples help to understand the different phases of the process.
