Mathematical Application Seminar

Spring 2008

Mondays 11:10 – 12:10pm.

Monroe Hall, 2115 G Street, Room 267



Math Dept Colloquium

Topology Seminar

Applied Math Seminar

Combinatorics Seminar

Logic Semnar

Graduate Seminar





February 4, 2008, Monday 11:10 – 12:10pm

Speaker: Xianfeng David Gu (CS dept, Stony Brook Univ.


Title: Computational Conformal Geometry, Algorithms and Applications

Place: Monroe Hall, 2115 G Street, Room 267  


Abstract: Computational conformal geometry is an interdisciplinary field,

 combining modern geometry theories from pure mathematics with computational

 algorithms from computer science. Computational conformal geometry offers

 many powerful tools to handle a broad range of geometric problems in

 engineering fields. This work summarizes our research results in the past

 years. We have introduced efficient and robust algorithms for computing

 conformal structures of surfaces acquired from the real life, which are

 based on harmonic maps, holomorphic differential forms and surface Ricci

 flow. We have applied conformal geometric algorithms in computer graphics,

 computer vision, geometric modeling and medical imaging.



February 11, 2008, Monday 11:10 – 12:10pm

Speaker: E. Arthur Robinson (Math Dept, GWU)

Title: An introduction to the use of algebraic statistics in modeling

biological sequence data.

Place: Monroe Hall, 2115 G Street, Room 267  


Abstract: We discuss the method of algebraic statistics, which uses computational

algebraic geometry (e.g., Groebner bases) to model DNA and RNA sequences.

This idea was pioneered by Lior Pachter and Bernd Sturmfels. The talk is expository.

It will cover the basic ideas behind this method and consider some simple examples.


February 18, 2008,  President’s Day. GWU is closed.

No talk scheduled.

(A previously scheduled talk by Teresa Przytycka is rescheduled to be on March 3).


February 25, 2008, Monday 11:10 – 12:10pm

Speaker: Li Chen (UDC, CS Dept)

Title: Connectedness in digital space

Place: Monroe Hall, 2115 G Street, Room 267  


Abstract:  This talk will begin with an  overview on digital geometry, digital space connectivity,

and digital objects such as digital curves and surfaces. Then we will focus on digital

functions and connectedness. In addition, the necessary and sufficient condition for

the existing measure regarding to connectedness will be presented.  We will also explore

related topics including the digitally "continuous" parts, graph-based spanning trees,

and the maximum connectedness. Finally,  we will discuss some applications of

connectedness to image segmentation.



March 3, 2008, Monday 11:10 – 12:10pm

Speaker: Teresa Przytycka, NIH | NLM | NCBI

Title: Towards uncovering connections between graph-theoretical properties of nodes in

        protein interaction network and their biological essentiality.

Place: Monroe Hall, 2115 G Street, Room 267


Abstract: An intriguing question in the analysis of biological networks is whether biological

characteristics of a protein, such as essentiality, can be explained by its placement in the network,

i.e., whether topological prominence implies biological importance. One of the first connections

between the two in the context of a protein interaction network, the so-called centrality-lethality rule,

was observed by Jeong and colleagues (Jeong et al. 2001) who demonstrated that high-degree nodes

or hubs in a protein interaction network of Saccharomyces cerevisiae contain more essential proteins

than would be expected by chance. Even though the correlation between degree and essentiality was

confirmed by many independent studies, the reason for this correlation remains illusive.


I will discus several hypotheses about putative connections between essentiality of hubs and the

topology of protein-protein interaction network that have been proposed recently and demonstrate

that these explanations are not always supported by the properties of protein interaction networks.

I will also discuss an alternative explanation.


March 10, 2008, Monday 11:10 – 12:10pm

Speaker: Sudip Bose (GWU, Statistics Department)

 Title: Methods of algebraic geometry in biology and statistics

Place: Monroe Hall, 2115 G Street, Room 267


Abstract: This is an expository talk about the uses of computational commutative algebra (CCA)

in biology, statistics and related fields.  As a simple example, one may note that

the probability distribution from the Hardy-Weinberg principle in genetics can be viewed

as an algebraic variety.  The work of Diaconis and Sturmfels in the early 90s applied

Buchberger's methods to contingency tables.  Pistone and Wynn demonstrated the use

of CCA in design of experiments.  The study of Boolean algebras leads to

applications in modeling biological systems, and in reliability.  In fact, rings and ideals

arise naturally in the study of probability distributions and standard statistical models.

The focus of the talk will be on the connections rather than specific details of the

application of, say, Grobner bases, to the solution of optimization problems in statistics and biology.



March 17, 2008. GWU pring break. No seminar.

March 24, 2008, Monday 11:10 – 12:10pm

Speaker: Ken Shaw (ONR)

Topic: Compressive Sampling


Place: Monroe Hall, 2115 G Street, Room 267  


Abstract: This is an expository lecture on the subject of compressive sampling (CS),

also known as compressive sensing, sparse sensing or sparse sampling. CS is a priority

research area for surveillance and homeland security purposes because of its potential to

help cope with large streams of data. Indeed, the real promise of CS lies not in data

reduction but sparse signal construction through adroit under-sampling.

The field is an attractive combination of mathematical optimization and probability.

Typical results involve convex minimization problems whose solutions are exact –

with "high probability." The talk intends to survey the field and point out some prospective

research problems. It will be accessible to a general mathematical audience.


Brief biographical sketch: Ken Shaw is an emeritus professor of mathematics at

Virginia Tech and until March 1, 2008, was a program officer at the Office of Naval Research.

He was a program officer in applied mathematics at the National Science Foundation

between 2002 and 2005. During the academic years 2005-2007 he served as director

of operations for the graduate program in mathematics and statistics at Georgetown University,

and is currently an Affiliated Faculty member in mathematics at Georgetown.


April 14, 2008.

No talk scheduled.

(A previously scheduled talk by Susan Cheng (CS Dept, GWU) will be rescheduled in Fall 2008)


April 21, 2008

No talk scheduled due to a thesis defense


April 28, 2008, Monday 11:10 – 12:10pm

Speaker: Hosam Mahmoud (GWU, Statistics Department)

Title: Algorithmic and mathematical issues in pattern matching

Place: Monroe Hall, 2115 G Street, Room 267  


Abstract: The speaker will present some of his own results in pattern matching

in strings, and more complex combinatorial structures such as random trees. The

intent is to give the audience an idea about the algorithmic and combinatorial

issues involved, and the flavor of the associated results (such as approximating

exact discrete distributions by continuous limits like the Gaussian and mixed normal

distributions). The talk is intended to a broad audience of scientists, specially

biologists interested in mathematical models, and the speaker will try to sketch the results

while staying away from technically involved proofs.   




Some future speakers (subject to confirmation)


Christian Laing (NYU)

Rahul Simha (GWU, CS)

Chen Zeng (GWU, bio-physics)


Speaker: Xiuzhen (Susan) Cheng (CS Dept, GWU)

Topic: Connected dominating set and its applications in wireless networks.

Place: Monroe Hall, 2115 G Street, Room 267  




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