On the occasion of her winning the Turing Award, Institute Professor Barbara Liskov participated in an interview with the MIT News Office in which she discussed her role in shaping the past, present and future of computer science.

Q. When you began your career in computer science, it was still a relatively young field. How have you seen this discipline evolve over time -- at MIT and elsewhere?

A. The change has been tremendous. When I started, most of the field was unexplored and there were obvious problems everywhere -- lots of low-hanging fruit, but also very fundamental issues that were poorly understood and very confusing. Today the field is on a very sound foundation. There are still many problems to work on, but now this work happens in the context of all that has gone before. When I started, this context was missing, so you just struck out on your own.

Oscilloscope traces showing the doubling in frequency of an electromagnetic signal processed through their experimental graphene microchip.by David Chandler

New research findings at MIT could lead to microchips that operate at much higher speeds than is possible with today's standard silicon chips, leading to cell phones and other communications systems that can transmit data much faster.

The key to the superfast chips is the use of a material called graphene, a form of pure carbon that was first identified in 2004. Researchers at other institutions have already used the one-atom-thick layer of carbon atoms to make prototype transistors and other simple devices, but the latest MIT results could open up a range of new applications. 

The MIT researchers built an experimental graphene chip known as a frequency multiplier, meaning it is capable of taking an incoming electrical signal of a certain frequency -- for example, the clock speed that determines how fast a computer chip can carry out its computations -- and producing an output signal that is a multiple of that frequency. In this case, the MIT graphene chip can double the frequency of an electromagnetic signal.

The light field, first described in Arun Gershun's classic 1936 paper of the same name, is defined as radiance as a function of position and direction in regions of space free of occluders. In free space, the light field is a 4D function - scalar or vector depending on the exact definition employed. Light fields were introduced into computer graphics in 1996 by Marc Levoy and Pat Hanrahan. Their proposed application was image-based-rendering - computing new views of a scene from pre-existing views without the need for scene geometry. (A workshop on image-based modeling and rendering was held at Stanford in 1998.)

The lesson plans on the AGPA website use the Learning Cycle as the instructional model for its lesson plans. The learning cycle rests on constructivism as its theoretical foundation. "Constructivism is a dynamic and interactive model of how humans learn" (Bybee, 1997, p. 176). A constructivist perspective assumes students must be actively involved in their learning and concepts are not transmitted from teacher to student but constructed by the student. In the early 1960's, Robert Karplus and his colleagues proposed and used an instructional model based on the work of Piaget. This model would eventually be called the Learning Cycle. (Atkin & Karplus, 1962). Numerous studies have shown that the learning cycle as a model of instruction is far superior to transmission models in which students are passive receivers of knowledge from their teacher (Bybee, 1997). As an instructional model, the learning cycle provides the active learning experiences recommended by the National Science Education Standards (National Research Council, 1996).

Arturo Porzecanski and David Isserman
American University Professor; Co-Founder of RareShare.org
Tuesday, February 10, 2009; 12:00 PM

American University professor Arturo Porzecanski and RareShare.org co-founder David Isserman discuss the importance of giving people with rare diseases the ability to connect with each other.

Porzecanski, who suffers from systemic capillary leak syndrome, has been able to use RareShare.org, a social networking site for those with rare diseases, to connect with other SCLS patients around the world.

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