Assignment # 5 - Sensor Placement

Article Review

Berry, J., Fleisher, L, Hart, W. Phillips, C. and Watson, J.-P. (2005) “Sensor Placement in Municipal Water Networks”, Journal of Water Resources Planning and Management, 131(3) pp. 237-243

This article addresses the issue contaminant events in water distribution systems. The motivation is higher vulnerabilities in water networks due its distributed geography. An approach for determining an optimal sensor configuration in water distribution systems is presented. The optimization method minimizes the expected fraction of population exposed to a contaminant event. Integer programming techniques was used. Four assumptions were used:

1) An attack occurs at a single point in the network
2) Total population exposed
3) Sensors protect downstream populations
4) Transitions between periods are ignored

Three data sets were evaluated. Data set 1 and 2 were test set from EPANET and one real network. A sensitivity analysis was performed in the model. It was evaluated how optimal solution would change considering changes in population densities and attack risks.

The article concludes that the optimization approach proposed can effectively solve large-scale sensor-placement problems. However, different modeling structures exists considering different performance objectives, alternative placement locations, temporal effects, and sensor costs.

Discussion

The aspect that called my attention is this article and that I think it is a great contribution to this kind of problem is the use of sensitivity analysis. Due the uncertainties presented in some datasets, especially in water distribution systems, which obtaining data from water utilities is usually difficult, performing sensitivity analysis helps in validating the results. Future research could incorporate different temporal patterns and mobility data to better understand the variation in water demand during the day or even year.