Two UCSB professors were recently invited to join the National Academy of Engineering (NAE), keeping UCSB ahead of Caltech with almost one-fifth of its engineering faculty sharing the honor.

Electrical and computer engineering professor Larry Coldren and mechanical engineering and computer science professor Linda Petzold were elected to the NAE on Feb. 13. UCSB now has 24 faculty members in the NAE, making it one of only a small number of universities with such a high proportion of engineering faculty in the academy.

Academy members continue to work at their current private sector or academic positions, but also serve in the national academy. The NAE conducts research both independently and for the U.S. government with the intent to address the public need for engineering assistance, according to the NAE website.

“Usually the election is based on a career of accomplishments,” said Matthew Tirrell, dean of the College of Engineering.

“We have 135 regular faculty members, and basically 24 [NAE] members,” Tirrell said. “This is almost one in five. There is only a handful of universities that have that have this many.”

Coldren is involved in the development of a new kind of laser called a vertical cavity surface-emitting laser (VCSEL) diode, Tirrell said. The communications industry is planning to use VCSEL lasers because of their technical and manufacturing advantages, Tirrell said.

The academy cited Coldren’s work on the VCSEL laser and the distributed Bragg reflector laser on its website. The other UCSB professor to be awarded this position works in a very different field.

“My specialty is computational science and engineering,” Petzold said. “It has to do with solving engineering and science problems on a computer which are too complicated to solve by hand.”

Petzold said that a lot of computer processes involve approximations, so when developing new methods, one must be sure the approximations are accurate enough. Petzold is currently working on a biological application for mathematical modeling.

“I am looking at computational models for cell regulatory systems – that would be for chemical reactions that occur within the cell,” Petzold said.

A computational model can be used to simulate the chemical interactions in the cell, Petzold said. It is helpful to use the computer models because the chemical concentrations in the cell are so low that it would be difficult to replicate the experiment in a beaker.

One type of computer model is called the stochastic model. In this model, the computer follows the laws of physics and random chance, like a Monte Carlo game.

A computer can run a stochastic model to determine whether the molecules will react, Petzold said. It is a very realistic approach because it closely matches reality, but it also has some drawbacks.

“In that sense, [the stochastic model] is exact even though it’s probabilistic,” Petzold said. “But it’s too slow, because even in the cell there are also chemical species that are present in really large quantities.”

Petzold said that current computers are unable to compute some very large models. Her current project is to combine the slow stochastic approach with differential equations, which are more effective at modeling the chemicals in large quantities.

In effect, Petzold is combining two mathematical approaches to address problems that require the benefits of both approaches. This technique is only about two years old, Petzold said.

Petzold said that her election to the academy will add to the reputation of the computer science and mechanical engineering departments.

“It’s good for my two departments here, which run on prestige. It helps them get better students,” Petzold said. “Science runs a lot on prestige.”