Department of Statistics Seminar
North Carolina State University
presents
Leah Martell, Marlina Dumasari & Lei Zhu
North Carolina State University
A Sampler of Graduate students
ABSTRACT
Three graduate students of the Department of Statistics at NCSU will present
brief overviews of their current research.
- Leah Martell -
"Wavelet Data Reduction and Multi-Resolution Decision-Making"
Recent advances in semiconductors and sensor instrumentation provide
opportunities for practitioners to collect data, useful in detecting
problems in operations, such as manufacturing productions, image
monitoring for security checking, unusual behavior in telephone usages
and so on. With automatic data collection tools, the data size
becomes too large for the standard statistical procedures to handle at
the regular data scale, especially on real-time operations. This
presentation proposes the idea of analyzing the "compressed data" to
detect process problems. We focus on the study of model selections om
wavelet data compression. This talk presents and compares several
criteria of selecting wavelet coefficients (used as the "compressed
data" in our study) to balance the goodness-of-fit and data
compression requirements. We illustrate the proposed ideas with
several real-life examples of detecting faults in manufacturing
processes. Our presentation will be conducted by pointing out a few
directions for future research.
- Marlina D. Nasution -
"Joint Analysis of Resighting and Radio-Telemetry Data"
Biologists often use more than one marking technique in wildlife
studies. From each of the mark types, it is common to conduct a separate
analysis of the recapture data to estimate parameters of interest, such as
survival rates.
Two data types that can be used in estimating survival rates are
resighting
and radio--telemetry data. The Jolly--Seber model is commonly used to
analyze
the resighting data, while the Kaplan--Meier product
limit estimators, modified for staggered entry of animals,
are used to analyze the radio--telemetry data. In a
study where some birds receive two types of tags
(i.e., leg bands and radios) and other birds receive just one
tag type (leg bands), the separate Jolly--Seber and
Kaplan--Meier analyses do not exploit all of the information in the
combined data sets.
In this paper, we propose a model and likelihood
for the combined analysis of resighting and radio--telemetry
data. In comparison to the separate analyses, this richer model
provides more information about the biology
and sampling processes. For example, the richer model permits assesment
of assumptions required by the separate analyses and allows
estimation of additional parameters. As an example, we apply the model to
annual resighting and monthly telemetry data from a population of Snail
Kites.
- Lei Zhu -
"Statistical Decoding of Potent Pools Based on Chemical
Structure"
Pooling experiments are widely used as a cost-effective approach for
screening
chemical compounds as part of the drug discovery
process in pharmaceutical companies. When a biologically potent pool is
found, the goal
is to decode the pool, that is, to determine which of the individual
compounds are
potent. Usually, only the responses are used in making the
determination. But it is
known that biological potency of a compound is highly dependent on its
chemical
structure. Thus we use compound structure information, in terms of atom
pairs, as
covariates for predicting the potency of individual compounds. Covariate
effects are
estimated in models with and without retesting. The procedure is
demonstrated using
real data from a drug discovery process at GlaxoWellcome.
Friday, October 29, 1999
3:35 - 4:35 pm
206 Cox Hall
Refreshments will be served on the second floor of Dabney Hall
(left of Room 222) at 3:00 pm.