Johns Hopkins Engineering Fall Magazine 2010


Under Control: Danielle Tarraf
TarrafAssistant Professor Danielle Tarraf straddles math and engineering. As a control theorist in the Department of Electrical and Computer Engineering, she jokes: “The mathematicians say this is applied work. But to the engineers, we’re mathematicians.”

Tarraf is engaged in a highly sophisticated niche area of applied mathematics that has been identified by the U.S. government as critical to scientific breakthroughs this century. Known as “control science,” it’s aimed at developing synthesis and validation tools that allow people to design autonomous systems—and trust the decisions made by these systems. Applications include robotics, cruise-missile defense, and unmanned vehicles.

Tarraf is interested in developing mathematical theories that drive action. She ponders yet-to-be developed theories and algorithms that address hybrid systems, or systems that are nonlinear with discrete and continuous dynamics.

She expects to put together a nucleus of grad students and postdocs to propel her work. With the Whiting School’s Laboratory for Computational Sensing and Robotics just across the quad, it’s not hard to imagine collaboration. “The roboticist would be our consumer… She would take our theories and apply them to make robots work,” she says.


Shaking Things Up: Narutoshi Nakata
NakataAssistant Professor Narutoshi Nakata will never forget waking up to the Great Hanshin Earthquake that shook Kobe, Japan, in 1995. “I was asleep in Osaka, 40 miles from the epicenter,” he says. “I woke to the house shaking.”

The terrifying quake shaped the young man’s future. Today, Nakata, of the Department of Civil Engineering, pushes the limits of science to develop experimental methods to understand how physical structures behave in earthquakes.

Recently, large-scale experimental facilities have become available for investigating the seismic performance of structures. Facilities like these have changed the way engineers perform experiments,” he says. “But they are still not large enough for mega-structures.” Nakata’s CAREER-funded research is directed toward developing methods that allow integration of experimental and computational models for earthquake simulation of large structural systems. The goal: development of highly sophisticated computer models that will augment shake-table research.

Nakata says, “In addition to gaining a better understanding of structural behavior, we are trying to develop reliable computational models, verify design codes of practice, and validate new materials for construction.”


Toward a Novel Way to Separate Particles: German Drazer
German DrazerTwo years ago, Assistant Professor German Drazer of the Department of Chemical and Biomolecular Engineering, teamed up with Joelle Frechette, also an assistant professor of ChemBE, to use LEGOs to visualize the behavior of particles, cells, and macromolecules in environments too small to be seen. Particles separate and move around obstacles in matter differently. This is important to understanding the field of microfluidics—used in the development of DNA chips and lab-on-a-chip technology. Drazer will use his CAREER award funding to continue his work, which is aimed at developing an integrated program to investigate the complex way suspended particles move in periodic, or ordered, systems.

While this work one day may have application to subjects such as how pollutants move through water, or how to sort DNA fragments, the assistant professor says his research addresses basic questions of science. “This will not tell me how particles move in complex disordered systems. But my point is: Why aren’t we taking advantage of periodic systems? Why aren’t we using them to develop particle separation technologies?”

—Mary Beth Regan