Signal Processing - July 2016 - 75

6.341x on edX.org, Spring 2015
Content-Oriented "Topics"
Lecture Videos
Exercises Between Videos

Spring 2015 Staff

One-Week Delay

Weekly Overview Videos

One-Week Delay

Weekly Homework Problems

One-Week Delay

Exams

Student

Discussion Forum
Lecture, Exercise,
Homework Threads
"Metapost" Threads About
High-Level Concepts

FIGURE 6. A diagram indicating the modes of interaction and flow of information between MIT staff and students, facilitated by the learning platform as it
existed in spring 2015.

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be more demanding than more introductory online courses. In
developing the 6.341x content for this platform, we chose to
work "close to the bare metal" of the edX platform to push
the boundaries and help to improve the platform.
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The process included adapting existing problem sets and
a background exam for the online platform, autograding, and
creating "finger exercises" to be given to the class and
responded to anonymously with fixed-function wireless
"clickers" during lecture. A histogram of responses to the
exercises, displayed immediately in class, impacted subsequent discussion and pace during the lecture [see Figure 7(b)]. The decision to use fixed-function clickers, as
opposed to, e.g., a phone or tablet app, was motivated by the
desire to keep the attention of students out of their e-mail
and browsers and focused on the lecturer and class discussion. The residential offering of the course in fall 2013 incorporated all of this online content to augment the live
lectures. In addition, the live lectures were video recorded.
Phase II. In spring 2014, the video recordings of fall 2013
lectures were heavily edited for crisper pacing, generating
video segments of appropriate content and length, and
sequencing with the finger exercises. In the residential offering, fall 2013 students were given a background exam on
Open edX and completed autograded problem sets on the
platform. The problem sets also used an in-browser "explanation box" system that was developed for the residential
course, in which students could enter symbolic equations,
proofs, and reasoning about their answers [see Figure 7(a)].
These were then electronically distributed to the course staff
for manual grading. Given the emphasis on a deep conceptual understanding that has traditionally been a key part of the

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residential course, the comment box system provided a way
to assess this understanding without diluting the problems to
fit within the constraints of an autograding system.
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The success of the online experience in the residential
course was a key motivation for carrying the material forward to a MOOC. Toward this end, the digital content was
continually expanded and refined until it was ready to be run
as a private beta for a limited number of participants from
industry in fall 2014, and then publicly deployed on edx.org
in spring 2015. This transition was a significant effort, funded largely by the MIT electrical engineering and computer
science (EECS) department and the MIT Office of Digital
Learning (ODL), together with edX. A significant effort was
required to edit the in-class video recordings for the MOOC
environment, which we found works best with short, ten-to
20-minute, well-paced segments. The in-class exercises
were also augmented and in some cases modified for a better
match to the edX environment.
Phase III. This phase consisted of first offering 6.341x as a
MOOC in fall 2014 in a beta version limited to 200 participants from industry, and then in spring 2015 as a fully
open online course. For all registered students, the autograded online background exam was made available before
the start of the MOOC to allow participants to assess their
background relative to the course content.
Phase IV. In the fall semester of 2015, residential 6.341 was
offered at MIT with the usual structure of three hours of
live class time per week, one hour of live recitation discussion with the teaching assistants (TAs), and a handwritten
midterm and final exam graded by the staff. The course
made full use of all of the digital online 6.341x content

IEEE Signal Processing Magazine

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July 2016

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http://www.edX.org http://www.edx.org
Table of Contents for the Digital Edition of Signal Processing - July 2016
