Network support for earthen embankment dam monitoring using wireless sensor networks

Abstract

Current dam monitoring practices result in a long lag time between the start of internal erosion and its detection. This long lag time precipitates expensive, disruptive, and technically challenging repairs. To compound issues with current dam monitoring practice, many of our nation's dams are at or near their intended design lives. Thus, we are in need of updated dam monitoring practices. This research contributes new and novel networking protocols needed to enable continuous, non-invasive, and autonomous monitoring of earthen embankment dams with a wireless sensor network (WSN). To fully realize autonomous WSN inspection, several WSN protocols are needed, including in-network localization. We contribute to the WSN localization research through the development of a novel in-network distance-based localization protocol that produces accurate mote location estimates. Our algorithm, which we call CAIRN+, produces more accurate location estimates than currently available distance-based algorithms. CAIRN+ optimizes algorithm performance based on network size, the number of anchors, and the ranging characteristics present within a WSN to produce accurate localization results in a variety of WSN configurations. Additionally, we contribute a received signal strength indicator (RSSI) pre-processing algorithm to decrease the impact of biased and noisy RSSI distance measurements on final localization results. We call our RSSI pre-processing scheme TARP. We show that TARP improves the localization performance of distance-based localization algorithms, including CAIRN+. With self-configuring network protocols, such as CAIRN+, WSNs are well suited for autonomous dam monitoring applications; however, the adoption of WSNs is subject to factors external to pure technical merit, and policy discords may be impacting the widespread adoption of WSNs. Specifically, within the wireless sector, intellectual property rights (IPR) undermine standards and the standardization process. To explore the tension between the two policy tools, IPR and standards, we present case studies on cellular communication and WSN technology innovation and standardization. We show how, within two wireless communication fields, these policy tools are working against one another and deterring technological innovation. We suggest potential policy options that could counteract the tension between patents and standards within the wireless field, which could help to encourage technological innovation and adoption of WSNs.