Group Photo at a New York Trade School Commencement Ceremony

This is a group photo mainly comprised of the school's administrators taken at the 1958 commencement ceremony of the New York Trade School. Original caption reads, "Back Row - Left to Right: William F. Vanderbeek, Robert H. Scholl, Gurdon Simmon, Miss Marie Kaye, and Peter H. Vermilye. Front Row - Left to Right: Gilbert G. Weaver, George E. McLaughlin, John Clarke, Enders M. Voorhees, Ralph Cole, Frank Casino and Charles Leidig." Black and white photograph.

A Gradient-Type Method For Real-Time State Estimation Of Water Distribution Networks

Drinking water distribution networks risk exposure to malicious or accidental contamination. Several levels of responses are conceivable. One of them consists to install a sensor network to monitor the system on real time. Once a contamination has been detected, this is also important to take appropriate counter-measures. In the SMaRT-OnlineWDN project, this relies on modeling to predict both hydraulics and water quality. An online model use makes identification of the contaminant source and simulation of the contaminated area possible. The objective of this paper is to present SMaRT-OnlineWDN experience and research results for hydraulic state estimation with sampling frequency of few minutes. A least squares problem with bound constraints is formulated to adjust demand class coefficient to best fit the observed values at a given time. The criterion is a Huber function to limit the influence of outliers. A Tikhonov regularization is introduced for consideration of prior information on the parameter vector. Then the Levenberg-Marquardt algorithm is applied that use derivative information for limiting the number of iterations. Confidence intervals for the state prediction are also given. The results are presented and discussed on real networks in France and Germany.