Teaching Computer Science Through Stories
Amin Vahdat says he wants to find the stories that students will remember when they leave the class
In a recent Advanced Computer Networks class, Professor Amin Vahdat offered a challenge to his students: Find a way to establish global trust in the Internet.
To lay the groundwork for this ambitious endeavor, Vahdat sketched the history of cryptography: from an attacking army's need for a verifiable secret code to Amazon.com's security scheme that rests on codes kept under armed guard in an underground bunker. Along the way he reminded his charges that the "six degrees of separation" rule applies to the Internet and also observed that a Middle Eastern institution may not trust an American corporation with its codes.
The all-male class of 10 computer science students wound up stumped. "Can we use the United Nations?" one student eventually asked.
Intellectual exercises that require more than technical know-how are essential to Vahdat's teaching. The winner of this year's David and Janet Vaughn Brooks Award for teaching excellence said he hopes to convey to his students "just how important the things they're working on can be."
His strategy is borrowed from one of his former University of California, Berkley professors, Robin Einhorn, whose undergraduate "Civil War and Reconstruction" class left a lasting impression. From that class, Vahdat still recalls Stephen Douglas's 1853 quip that the controversy his slavery position sparked allowed him to walk home from Washington D.C. "by the light of his own burning effigies."
"Telling stories, bringing it back to people" is how Vahdat said he conveys computer science concepts, although he concedes that compared to the Civil War and Reconstruction the stakes are lower and the people are often less interesting.
"For example, one story that I like to tell is how, on Sept. 11, CNN system administrators were busy ripping machines out of [AOL Time Warner-owned computer] clusters and switching them over from serving the Cartoon Network to serving up CNN.com." Besides casting computing experts as heroes, the incident provides a real-life question technical for his class: how can the same switching be done automatically?
Vahdat's approach is vindicated by students and colleagues. Senior Priscilla Alexander took one of Vahdat's computer networking classes based on the recommendation of three friends "with reputations for skipping classes." All three had attended Vahdat's class without fail.
"My friends were right," Alexander wrote in support of Vahdat's candidacy. "It's obvious he cares about the subject and the students."
Department of Computer Science chairman Alan Biermann said Vahdat's course evaluations consistently carry the same messages. They include: "He is a very good lecturer," "He combines theory and practice," "His course is aimed at the frontiers of the field" and "He is very knowledgeable about his field."
These testaments to his teaching come in addition to Vahdat's research, which, according to Biermann, has appeared in the most prestigious journals and conferences.
Besides ideas, what drives Vahdat is working with students.
"Students are the coin of the academic realm," said Vahdat, quoting another of his favorite Berkeley computer science professors, David Patterson. If that aphorism is true, then Vahdat is already minting. Students of his have been published at prominent conferences, led the software development of a successful startup, gone on to top graduate programs and his first Ph.D. student, Haifeng Yu, is now interviewing for teaching positions with the nation's leading computer science departments.
The key to supporting such student successes?
"One-on-one meetings," Vahdat said. "The key is just to get them started [talking]. Beyond that it's relatively easy." His policy is to meet with each student at least three times during a course.
Preparedness is another key to Vahdat's teaching. For the last five years he has used his computing expertise to organize his classes electronically: lectures are guided by PowerPoint slides that are archived on his Web site, where a semester's worth of projects and assignments are also posted.
Vahdat said he doesn't expect his early promotion to tenure in July to affect his teaching.
"My goals are much higher than tenure," said the Iranian-born professor, who began his computer science dissertation at the Berkeley with "the somewhat na¯ve goal of changing the world."
"My goal from my graduate school days hasn't gone away -- it's to improve the human condition," he said. "And the great thing about being a professor, and being in education, is that I get to multiplicatively increase my opportunity for doing important things -- in other words, having impact through the students I interact with."
Written by James Todd
Teaching Awards
The Robert B. Cox Award
The Howard D. Johnson Award
The Richard K. Lublin Award
Naomi Quinn, cultural anthropology
The Dean's Award for Excellence in Teaching (Graduate School)