Georgia Institute of Technology College of Sciences

Over the past 30 years, researchers have developed successively faster algorithms for the maximum flow problem. The best strongly polynomial time algorithms have come very close to O(nm) time. Many researchers have conjectured that O(nm) time is the "true" worst case running time. We resolve the issue in two ways. First, we show how to solve the max flow problem in O(nm) time. Second, we show that the running time is even faster if m = O(n). In this case, the running time is O(n^2/log n).

The Southeast Geometry Seminar is a series of semiannual one-day events focusing on geometric analysis. These events are hosted in rotation by the following institutions: The University of Alabama at Birmingham;  The Georgia Institute of Technology;  Emory University;  The University of Tennessee Knoxville.  The following five speakers will give presentations on topics that include geometric analysis, and related fields, such as partial differential equations, general relativity, and geometric topology. Jason Cantarella (University of Georgia);   Meredith Casey (The Georga Institute of Technology);  Kirk Lancaster (Wichita State University); Junfang Li ( University of Alabama at Birmingham)  Jason Parsley (Wake Forest University);

A discussion of the paper "RNA folding with soft constraints: reconciliation of probing data and thermodynamic secondary structure prediction" by Washietl et al (NAR, 2012).

Guided by direct experiments on many-legged animals, mathematical models and physical models (robots), we postulate a hierarchical family of control loops that necessarily include constraints of the body's mechanics. At the lowest end of this neuromechanical hierarchy, we hypothesize the primacy of mechanical feedback - neural clocks exciting tuned muscles acting through chosen skeletal postures. Control algorithms appear embedded in the form and skeleton of the animal itself. The control potential of muscles must be realized through complex, viscoelastic bodies. Bodies can absorb and redirect energy for transitions. Tails can be used as inertial control devices. On top of this physical layer reside sensory feedback driven reflexes that increase an animal's stability further and, at the highest level, environmental sensing that operates on a stride-to-stride timescale to direct the animal's body. Most importantly, locomotion requires an effective interaction with the environment. Understanding control requires understanding the coupling to environment. Amazing feet permit creatures such as geckos to climb up walls at over meter per second without using claws, glue or suction - just molecular forces using hairy toes. Fundamental principles of animal locomotion have inspired the design of self-clearing dry adhesives and autonomous legged robots such as the Ariel, Mecho-gecko, Sprawl, RHex, RiSE and Stickybot that can aid in search and rescue, inspection, detection and exploration.