Seminars Sorted by Series

Workshop on Topology: Identifying Order in Complex Systems

Dec
01
2010

Workshop on Topology: Identifying Order in Complex Systems

Patterns, Universality and Computational Algorithms
Nigel Goldenfeld
4:30pm|S-101

Can we use computational algorithms to make accurate predictions of physical phenomena? In this talk, intended for non-experts, I will give examples where complicated space-time phenomena can be exquisitely captured with simple computational...

Apr
06
2011

Workshop on Topology: Identifying Order in Complex Systems

Using Computational Algebraic Topology to Characterize Chromosome Instability in Cancer
Javier Arsuaga
3:00pm|University of Pennsylvania, David Rittenhouse Lab., Room A6

DNA copy number abnormalities (CNAs) play an important role in cancer, and are associated with tumor progression as well as clinical outcome. Using microarray based comparative genomic hybridization (CGH), analysis of CNAs across large cohorts of...

Apr
06
2011

Workshop on Topology: Identifying Order in Complex Systems

Persistent Cohomology and Circular Coordinates
Vin de Silva
4:30pm|University of Pennsylvania, David Rittenhouse Lab., Room A6

High-dimensional data sets often carry meaningful low-dimensional structures. There are different ways of extracting such structural information. The classic (circa 2000, with some anticipation in the 1990s) strategy of nonlinear dimensionality...

Dec
07
2011

Workshop on Topology: Identifying Order in Complex Systems

Why Things Don't Fall Down, How Tensegrities Work
Robert Connelly
2:00pm|Princeton Univ., Jadwin Hall, Prin. Center for Theoretical Sciences

How do things hold up? What are the geometric ideas that are involved? One of the principles can be seen with simple models, where sticks are suspended in mid-air with inextendable cables. These were called tensegrities by Buckminster Fuller...

Feb
01
2012

Workshop on Topology: Identifying Order in Complex Systems

Probabilisitc Perspective on Topological Data Analysis
Sayan Mukherjee
2:00pm|Rutgers University, Hill Center, Room 705

In this talk we discuss the recent area of topological data analysis (TDA) from a probabilistic perspective. The talk falls under two parts. The first part of the talk considers a classic object in topology and geometry, a (Whitney) stratified space...

Feb
01
2012

Workshop on Topology: Identifying Order in Complex Systems

The Taming olf the Screw: or How I Learned to Stop Worryhing and Love Elliptic Functions
Elisabetta Matsumoto
3:30pm|Rutgers University, Hill Center, Room 705

Topological defects pervade a wide range of physical systems, from superconductors to smectic liquid crystals. The behavior and interactions of such singularities impart many materials with a wealth of rich behavior. Just as flux vortices in the...

Mar
07
2012

Workshop on Topology: Identifying Order in Complex Systems

Computing Homology Cycles with Certified Geometry
Tamal Dey
3:30pm|S-101

Computation of cycles representing classes of homology groups is a fundamental problem arising in applications such as parameterization, feature identification, topology simplification, and data analysis. Variations of the classical Smith Normal...

Apr
04
2012

Workshop on Topology: Identifying Order in Complex Systems

Hodge Decomposition and Online Ranking on Random Graphs
Lek-Heng Lim
2:30pm|David Rittenhouse Lab.(Room A-7), University of Pennsylvania

Suppose a large number of voters have each rated or compared a small subset of a large number of alternatives, how could we rank the alternatives based on these data? The rank aggregation problem is fraught with famous difficulties --- Arrow's...

Apr
04
2012

Workshop on Topology: Identifying Order in Complex Systems

Self-Assembly of Spherical Colloidal Particles at Low N
4:00pm|David Rittenhouse Lab.(Room A-8), University of Pennsylvania

The number of energetically stable structures that a system of N particles can form grows exponentially with N. Stabilizing any one structure over all others is thus a challenging problem. We consider a system of N spherical colloidal particles that...

Nov
07
2012

Workshop on Topology: Identifying Order in Complex Systems

Continuum Percolation and Duality with Equilibrium Hard-Hyperparticle Systems
1:00pm|David Rittenhouse Lab.(Room 4E19), University of Pennsylvania

I derive a new set of bounds on the percolation threshold of a class of continuum percolation models consisting overlapping convex hyperparticles in d-dimensional Euclidean space. The bounds converge to one another as the space dimension increases...

Nov
07
2012

Workshop on Topology: Identifying Order in Complex Systems

Dynamic Programming for ab-initio Prediction of Protein Folding Routes
Julia Hockemaier
2:30pm|David Rittenhouse Lab.(Room A8), University of Pennsylvania

I will demonstrate how the Cocke-Kasami-Younger (CKY) algorithm, a standard dynamic programming technique that is normally used in natural language parsing, can be adapted to give us novel insights into the protein folding problem. If we assume that...

Nov
07
2012

Workshop on Topology: Identifying Order in Complex Systems

Membranes, Curvature and the Endoplasmic Reticulum
Greg Huber
4:00pm|David Rittenhouse Lab.(Room A8), University of Pennsylvania

"I seemed to see the membraneous and cylindrical tubes tremble beneath the undulation of the waters." - Jules Verne (describing Captain Nemo's underwater garden in 20,000 Leagues Under the Sea) For over half a century, microscopists have seemed to...

Feb
06
2013

Workshop on Topology: Identifying Order in Complex Systems

Visualizing and Exploring Molecular Simulation Data via Protein Energy Landscape metaphor
Yusu Wang
2:00pm|Proteomics Bldg. 120, Rutgers, The State University of New Jersey

The rapid improvements in computational power have enabled researchers to produce large amounts of molecular simulation data. Hence there is a pressing need to be able to analyze such data to enhance our understanding of molecular dynamics. However...

Feb
06
2013

Workshop on Topology: Identifying Order in Complex Systems

Community Structure in Networks
Mason Porter
3:30pm|Proteomics Bldg. 120, Rutgers, The State University of New Jersey

Networks arise pervasively in biology, physics, technology, social science, and myriad other areas. They consist of a collection of entities (called nodes) connected via ties, and they typically exhibit a complicated mixture of random and structured...

Feb
06
2013

Workshop on Topology: Identifying Order in Complex Systems

Linear Algebra over Cell Complexes: Applications to Data, Coding and Sensor Networks
Justin Curry
5:00pm|Proteomics Bldg. 120, Rutgers, The State University of New Jersey

In this talk we introduce a discrete and computable version of a mathematical technique known as sheaf theory. This tool provides a method for extracting qualitative topological features of data over a space, rather than of the space itself. We...

Mar
06
2013

Workshop on Topology: Identifying Order in Complex Systems

The Optimality of the Interleaving Distance on Multidimensional Persistence Modules
5:00pm|S-101

Persistent homology is a central object of study in applied topology. It offers a flexible framework for defining invariants, called barcodes, of point cloud data and of real valued functions. Many of the key results of the last several years in the...

Apr
03
2013

Workshop on Topology: Identifying Order in Complex Systems

Properties of Cellular Microstructures: Polycrystals, Foams, and their Idealizations
David Srolovitz
1:30pm|David Rittenhouse Laboratory, 4N12

Cellular structures are compact domains joined along codimension 1 interfaces to fill space. Such cellular microstructures are ubiquitous in materials science and biology. I will briefly review the basic theory of cellular structure evolution via...

Apr
03
2013

Workshop on Topology: Identifying Order in Complex Systems

Towards a Covariant Theory of Coarsening via Emergent Symmetries
Stephen Watson
4:30pm|David Rittenhouse Laboratory, A8

The scaling symmetries of both static and dynamic critical phenomena naturally yield associated power laws and scaling functions. Going beyond simple scalings, we reveal how general emergent symmetries control the coarsening statistics of non...