MIT doctoral students thrive doing research at Lincoln Laboratory

MIT doctoral candidates continue to choose MIT Lincoln Laboratory as the place to conduct thesis research. Every year for more than three decades, the Laboratory has hosted about 20 research assistants (RAs). Working with engineers and scientists, RAs contribute to sponsor programs while investigating the questions that will evolve into their doctoral theses.

The facilities, the research thrusts, and the reputations of staff members are prime inducements behind the decision to spend three to five years as an RA in a Laboratory group. For Joseph Lane, an RA in the Advanced Electro-Optical Systems Group, the chance to interact with various experts was motivation. "The scale of the projects that the Lab works on seems to require experts in all fields of engineering. I knew I would get a chance to work with and learn from these people. I was also persuaded by the really applied approach to research that the Lab practices."

Nancy Chen found that the Human Language Technology Group "is one of the few labs in the world that fit all my needs. Many researchers at the Lab were interested in my research topic, which required a lot of resources—large-scale data, intensive computing power, and guidance from both speech science and engineering," says Chen, who completed a thesis that proposed a new approach to dialect identification.

The Human Language Technology Group is one of the pockets of specialized work that draws a steady stream of research assistants. "At any one time, we usually have two to six students at different stages of their thesis development," says Joseph Campbell, associate leader of the group and one of Chen's thesis supervisors.

Three new PhDsIn June 2011, three doctoral students who did their thesis research in the Human Language Technology Group were awarded PhD degrees from MIT. From left, Zahi Karam, PhD in electrical engineering; Nancy Chen, PhD in biomedical engineering; and Tian Wang, PhD in biomedical engineering. The group, formerly called Information Systems Technology, has mentored many students over the years, but this is the first time the group has had this many PhD degree recipients at one time.

Advantages at Lincoln Laboratory
By choosing to work at the Laboratory, students reap an important benefit: the experience of engaging in professional activities. "My supervisors were very adamant on supporting students to attend conferences. These experiences have helped me learn how to present my work, expand my professional network, and build confidence," says Chen.

Zahi Karam, whose thesis research in the Human Language Technology Group involved the classification of large data sets applied to speaker verification, appreciated the focus on professional development. "The Lab provided me with the opportunity, while still new there, to attend an eight-week workshop at Johns Hopkins University on speaker verification where I was introduced to the greater speaker verification community, and the work there became the seed of my PhD research."

Campbell explained that his group constantly publishes and encourages its student researchers to enter papers for all major speech conferences, including the prestigious International Conference on Acoustics, Speech, and Signal Processing (ICASSP). "When Nancy presented her paper at the ICASSP 2011 in Prague, one of the world's leading phoneticians was the first to ask questions about her work, a very radical method for identifying dialect. His questioning was tougher than any she faced in defending her thesis the month before, and she clearly demonstrated her capabilities."

Participation and publication in professional conferences also enhance students' resumes, especially if their work garners accolades such as Chen's paper being named a Best Student Paper at the 2011 ICASSP or Tian Wang's paper, coauthored with thesis advisor Thomas Quatieri, receiving the MIT Lincoln Laboratory 2010 Best Paper Award. Wang, who did research for both his master's and doctorate degrees in the Human Language Technology Group, is one of five students who have earned doctorates under Quatieri's supervision.

Students appreciate the more industry-like environment of the Laboratory. "That the Lab is not quite the same as an academic institution meant a lot of things," says Wang. "I could see very clearly the bigger picture of how my research related to issues of national importance. I feel that the culture at the Lab as something similar to an industrial research setting was great preparation for my current career outside academia."

Lane, in comparing the Laboratory's more industrial environment to that of an academic setting, notes that "many tasks that might prove painful on campus can be made rightfully simple at Lincoln. If there is measurement equipment, any tools, or devices that are necessary or would make a job easier with better results, there's rarely ever hesitance to purchase it, that is, if the Lab doesn't already have it, which is also rare."

Lincoln Laboratory offers the resources of an industrial research laboratory in a stimulating academic research environment. Karam found this duality and the connection to MIT to be contributing factors to his success. "An advantage at the Lab is the unmatched resources available to the students, in terms of access to computing resources and the vast wealth of knowledge of the researchers, which they are eager to share. The ability to co-exist between MIT and Lincoln Lab provided me with access to academic resources and classes at MIT as well as access to the faculty there, specifically my co-advisor Professor [Alan] Oppenheim, and Professor [Tommi] Jaakkola, a member of my committee."

Personal connections
Laboratory staff members find satisfaction in mentoring highly motivated young researchers and value new perspectives students bring. "The three students from our group who earned their PhDs this year all did very original work," says Campbell. "I was one of Nancy's supervisors so I know her work best. Her approach to dialect identification is unique; her system attempts to inform analysts as to why the dialect determination was made. Zahi exploited communication graphs between people to determine who is talking and to whom; he developed subspace and graph methods to analyze and visualize large data sets. And, Tian developed a novel framework for two-dimensional speech signal processing; he applied this to speech enhancement and speaker separation."

Students find the staff exceptionally supportive. Chen recalls "feeling frustrated about not being able to meet my first paper deadline, but Joe [Campbell] and Wade [Shen, her other supervisor] told me to hang in there and to call anytime, even after midnight, if I needed to chat." Wang’s experience was similar and "very comforting to a 'green' graduate student" who appreciated being able to ask questions of any of the group's experts. Wang also values the open-door policy of his advisor Quatieri, writing in his thesis acknowledgments, "Throughout the past five years, I have greatly appreciated Tom's dedication to students and his infectious enthusiasm for research." Karam is more emphatic, "My success is directly a result of Bill's [Campbell] great mentoring and advising as well the advice and interaction with Doug Reynolds and Doug Sturim."

Over the years, although the Laboratory has hired some of the students after they completed their degrees, many students move on, returning to regions closer to home, exploring entrepreneurial opportunities, or seeking different challenges in industry.

Posted October 2011

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