LEHIGH UNIVERSITY
Grant: $209,835 - National Science Foundation - Jul. 21, 2009
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Award Description: The overall purpose and expected outcomes of the project are described as follows. The project investigates a novel wireless signal network that can function as a versatile sensor to characterize properties of subsurface geo-media and to monitor indiscriminate geo-events. The proposed network is based upon algorithmic evaluation of real-time link quality information as functional signals among distributed wireless transceivers. The concept of functional signal advocates that the variation of the link quality between wireless transceivers can be used as an effective sensing mechanism which reflects characteristics of geo-media subjected to various geo-events. This novel method aims to integrate wireless signal networks providing a global geo-media measurement system and to optimize the usage of link quality data from embedded wireless sensors in distributed configuration. This not only enables to evaluate and visualize entire geo-system but also helps develop knowledge of functional-signal map to benchmark such continuums through spatiotemporal calibrations of wireless link quality. The work plan includes small-scale 1D calibrations of functional signal under various geo-conditions, radio propagation model design, simulator development for wireless signal networks, and large-scale laboratory tests at Lehigh University and Lafayette College, in addition to educational and outreach efforts. Research results will be disseminated through peer-reviewed publications. A modulated course will be developed for geo-engineering and wireless signal network studies. The research team will partner with various institutional outreach programs to target underrepresented groups and participate to a yearly workshop for high school students.
Project Description: The goal of the activities in the quarter ended on 09/30/2009 was to determine the critical soil matrix parameters and signal transceiver configurations for 1D calibrations of the functional signal under various geo-conditions. Experiments were designed and conducted to test signal strength variations as a function of soil burial depth, transceiver inter-spacing and presence of water in soil. Four translucent boxes were constructed to hold four individual transceivers with their antennas extending to outside through a water tight opening on each box. The soil matrix tests were conducted in a steel box of dimensions 122cm (4ft) long, 91cm (3ft) wide and 51cm (1.7ft) high. The top(s) of the soil layer(s) were covered with aluminum foil to ensure the boundary condition. The metal boundaries helped reduce the signal escape and noise effect significantly, which we had experienced in preliminary tests conducted in an open air wooden box. The steel box was first filled with dry sand in lifts and the signal strength between adjacent transceivers was measured in multiples for the two long (119cm) and short (85cm) side corners of the box and diagonally across (169cm) opposite corners. The burial depths of the transceivers were increased by placing 10-inch thick uniform lifts of sand over them up to 40 cm of total burial. The same experiments were repeated with wet sand compacted slightly at 8% water content. The density data of the sand in both the dry and wet tests were kept close to each other to alleviate any influence of density variation on signal strength. The dry density and the porosity of the dry and the wet sands were measured as 1.345g/cm3, 0.5 and 1.458g/cm3, 0.45, respectively. The results showed that the signal strength is significantly influenced by the presence of water in the soil matrix, with a steeper drop with depth in the wet sand case. Work is continuing to repeat the tests in sufficient numbers for statistically sound calibrations.
Jobs Summary: A Pre-doctoral research associate has been hired to work on this project. The appointment is expected to be four-months in duration. The pre-doctoral research associate will work under the direction of the PI on research involving the improvement of spatial resolution and accuracy of BOTDR measurements for event monitoring in civil infrastructure. (Total jobs reported: 0)
Project Status: Less Than 50% Completed
This award's data was last updated on Jul. 21, 2009. Help expand these official descriptions using the wiki below.
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