Annual Report 2008.pdf - SAMSI

XuanLong Nguyen. With his advisor, James Clark, he is developing his dissertation research
plan which will involve the use of environmental sensor network data in examining plant-insect
interactions in a mixed-hardwood forest. His experience in the SAMSI program will prepare him
for dealing with data analysis of often faulty sensor data. During his graduate fellowship, he
presented a poster at SAMSI's Environmental Sensor Network Workshop (January 2008)
concerning modeling of battery data from a wireless sensor network to identify the effects of
transmission and data collection on sensor node longevity. He has also given a presentation as an
introduction to ecological modeling with sap ux data during SAMSI's PostDoc/Graduate Student
Seminar (November 2007), a presentation regarding the use of mathematics and statistics in
ecology and environmental sciences at the SAMSI Undergraduate Workshop (March 2008), and
plans to give another presentation during the SAMSI's PostDoc/Graduate Student Seminar (April
2008).
From David Bell
Research Area – Plans:
Broadly, environmental/ecological modeling in the context of community and forest ecology is
of particular interest as well as environmental sensor network functionality. Specifically, I am
interested in using data from a wireless environmental sensor network along with information
pertaining to the demography of trees and the diversity of insects in southeastern forest
communities to address questions associated with plant-insect interactions. The use of fine-scale
environmental data in studies of ecological community dynamics is a promising avenue of
investigation. I am also interested in exploring transmission issues and functionality in a
wireless network deployed in a “real world” environment. Past work on this subject has largely
focused on simulations, rather than actual applications in ad hoc sensor networks. The
application of models developed using simulations on data from a wireless network provides an
opportunity for validation of network theory in variable and difficult transmission environments.
Presentations
Review of EPA Air Quality Adjustment Procedures in Ozone Exposure Models, Novermber 26,
2007
Relationship of SAMSI Research to Ph.D. Dissertation:
Initial work for examining relationship between environmental stress and plant-insect
interactions as well as development of statistical and modeling knowledge should lay the ground
work for exploring my dissertation topic: plant-insect interactions in a southeastern mixedhardwood
forest. I am particularly interested in developing models that integrate insect
diversity, plant community, and environmental data in a statistically rigorous manner.
Hierarchical Bayesian approaches are one avenue to pursue in addressing these goals, but clearly
not the only option.
Kristian Lum (Duke University) initiated her association with the program with project in the
Fall Sensor Networks for Environmental Modeling Course on improvements based on network
queries to application-level Bayesian inference on sensor networks in the case of prolonged
failures. She also attended the opening workshop. She is now investigating parameter inference
on sensor networks using latent variables, the likelihood alone, and the EM Algorithm, and the
effect of these inference techniques on network energy consumption. She will use this work as
part of her preliminary exams in April 2008.