Special Section >> Inside Purdue's Envision Center
AN ENVISION STUDENT uses the Chinese
Garden application in the FLEX environment
and is transported to an Eastern China
garden in the year 1708.
Purdue University’s remarkable center breaks away from the classroom
experience and brings true multi-sensory discovery and learning to students.
By Krishna P.C. Madhavan, Laura L. Arns, and Gary R. Bertoline
There is no doubt that the last decade has seen an explosive increase in the
quantity of data available for discovery and learning purposes. And this is
a good thing—humans do, after all, process their data through a variety
of senses: auditory, oral, and tactile senses, plus the sense of sight. Yet,
the highly textual nature of traditional datasets has represented a purely visual
data form that caters only to a small percentage of the number of methods in
which humans can understand data. In other words, most of these large volumes
of data are considered to be “perceptually inferior”; says Grok-It
Concepts (Grok-It Science; www.medibolt.com/conbottom.htm).
This, in essence, is the problem that the field of data perceptualization attempts
to address. |
What is data perceptualization? Data perceptualization deals
with various theoretical and practical techniques that can translate large volumes
of data into useful information by allowing, according to Stuart K. Card, “…a
richer use of many [human] senses, including sound and touch, to increase the
rate at which people can assimilate and understand information” (from
“Visualizing Retrieved Information: A Survey,” IEEE Computer Graphics
and Applications, March 1996). And Grok-It Science states that while the fundamental
principle underlying data perceptualization is intuitive and powerful, it is
the process of translating data to overcome “perceptual inadequacy”
itself that represents a new and emerging frontier in science and technology.
Bridging Discovery and Learning
That’s where the NSF-funded Envision Center for Data Perceptualization
(www.envision.purdue.edu)
at Purdue University (IN) comes in. The Center is organized
under the Office of the Vice President for Information Technology, and is an
interdisciplinary, high-performance, perceptualization showcase facility to
support discovery and learning at Purdue. After all, it has long been understood
that “undergraduates need to become an active part of the audience for
research” (Reinventing Undergraduate Education: A Blueprint for America’s
Research Universities. The Boyar Commission on Educating Undergraduates in the
Research University, 1998; naples.cc.sunysb.edu/Pres/boyer.nsf),
and that “the basic idea of learning as inquiry is the same as the idea
of research; even though advanced research occurs at advanced levels, undergraduates
beginning in the freshman year can learn through research.
” But the Envision
Center is not designed for students alone: While students (undergraduates and
graduates) are exposed to the latest technology in the field of data perceptual-ization
computing through the center’s instruction, Purdue faculty members use
the facility for displaying and interacting with scientific data in innovative
ways. This dual focus of the Envision Center acts as a strong bridge between
discovery and learning, as it encourages active student participation in research
projects.
Catalysis Project: Understanding at a Rapid Pace. One of those
projects is the Catalysis Project, currently in progress at the center. Catalysis
is a prime example of the link that the Envision Center is forging between discovery
and learning. Importantly, it provides undergraduates and graduate students
the opportunity to learn and explore, and at the same time, contribute to real-world
research. Certainly, the development of new materials for new applications is
one of the outstanding technical challenges in material science and chemical
engineering. And in fact, recent advances in high throughput experimentation
have accelerated the testing of new materials by an order of magnitude; the
availability of powerful supercomputers, coupled with the evolution of the Teragrid,
is enabling high throughput of a large number of molecular structures.
The key challenge addressed by the Catalysis project is to use new perceptualization
tools to rapidly focus the vast amount of data that is generated, in a form
that a materials expert can perceive, understand, and analyze at a fast pace.
Funded by the Department of Energy and a 21st Century Grant from the state of
Indiana, students from the Envision Center partner with students in the Chemical
Engineering department to integrate their classroom projects into mainstream
research projects. In pedagogical terms, by allowing students to actively engage
with the concepts they are learning, the Catalysis project promotes situated
learning. David Stein, in the online Situated Learning in Adult Education (ERIC
Digest No. 195, 2000; http://www.cete.org/acve/docgen.asp?tbl=digests&ID=48), states that “in the situated learning approach, knowledge
and skills are learned in the contexts that reflect how knowledge is obtained
and applied in everyday situations…By embedding subject matter in the
ongoing experience and by creating opportunities for learners to live subject
matter in the context of real-world challenges, knowledge is acquired and learning
transfers from the classroom to the realm of practice.”
The infrastructure available at the Envision Center plays a critical role in
bridging that gap between discovery and learning. Some of the exciting technologies
in use at the Center are:
VR Theater. Virtual Reality (VR) refers to “immersive,
interactive, multisensory, viewer-centered, three-dimensional, computer-generated
environments and the combination of technologies required to build these environments”
(Carolina Cruz-Neira, Projection-Based Virtual Reality: The CAVE and Its Applications
to Computational Science. Ph.D. Thesis, University of Illinois, 1995). VR theaters
immerse users in the environment they are viewing. With such theaters, users
aren’t just passive observers in the computer-generated world, but are
interacting with the various components of the environment in real-time. Envision’s
VR Theater is a Fakespace FLEX System (
www.fakespace.com), featuring three 8 x 10 foot panels for rear projection of large-scale
3D images. These movable screens can be easily and rapidly rearranged to form
a semi-enclosed “room” with three walls plus a fourth panel as the
floor—an arrangement that creates a 3D immersive virtual environment.
The VR Theater is also equipped with a state-of-the-art tracking system that
allows corrective perspective rendering and direct interaction with the virtual
environment. A fivechannel speaker system in the corners of the facility adds
surround-sound cues to the virtual reality environment. Depending on the task
at hand, the VR Theater is driven either using a 32-processor SGI Oynx2 computer,
or an 8-processor SGI Oynx4. A high-end Windows and Linux PC cluster has been
added to the already powerful VR Theater.
Motion Capture. In the virtual reality world, the process
of recording a person’s movements or other live motion event, and converting
those movements into a digital, 3D representation of the motion is called motion
capture. The Envision Center houses a portable STT Motion Captor optical motion
capture system composed of six infrared cameras on tripods, and as many as three
linked computers. The system is operated in collaboration with the Department
of Visual and Performing Arts, and is capable of capturing the movements of
two people simultaneously. During the last academic year, for instance, graduate
and undergraduate student groups from the Computer Graphics Technology program
at Purdue used this system to produce an interactive dance performance in association
with the Department of Visual and Performing Arts. A solo dancer wore the motion
capture suit on stage, during the performance (see above). Data gathered from
the suit was then used to create imagery which was projected onto two large
screens on the stage.
Tiled Wall. The tiled display wall at the Envision Center
is a 7 x 12 foot high-resolution display made up of a grid of 12 smaller projection
displays controlled by many computers working together. The wall is capable
of displaying 4,096 pixels horizontally and 2,304 pixels vertically, for a total
of 9.4 million pixels—about five times the resolution found on a typical
desktop workstation. The display system is extremely versatile, and can be used
for2D, 3D, or stereo production of single, large-scale continuous images (see
the image below). This capability is particularly useful when working with satellite
imagery of geographical areas, and thus, not surprisingly, has immediate implications
for homeland security and environmental protection initiatives. Yet, the tiled
wall can also be used to display different graphics on each individual screen,
or a combination of screens in the grid can be utilized for a variety of media
displays. Image generation for the tiled wall is driven by a cluster of 12 high-performance
PCs with high-end graphics cards.
Access Grid. The Envision Center places a premium on collaborating
with researchers and student groups throughout the world, and the Access Grid
(AG) at the center helps to make that possible. The Access Grid is an ensemble
of resources that includes multimedia large-format displays, presentation and
interactive environments, and interfaces to grid middleware and visualization
environments. (For more on AGs, go to
www.accessgrid.org).
The AG allows participants from many geographically distant sites to communicate
and collaborate with each other easily and inexpensively (see the visual, right).
But unlike traditional videoconferencing, it runs over Internet2, using open
source software developed by Argonne National Laboratory (www.anl.gov).
The software is quite flexible, allowing each site to operate using a variety
of hardware setups that range from individual laptop-based nodes to large classrooms
with multiple projected displays. And by creating shared applications and tools,
the AG also allows participants to share more than just video streams. In Spring
2004, the Envision Center developed an Introduction to Virtual Reality course
jointly taught by faculty at Purdue and Indiana University,
via the Access Grid. The class was also offered in Fall 2004 by Purdue and Iowa
State University. Notably, a student in the spring class launched the
development of AGJuggler, a toolkit that allows sharing of virtual environments
and stereographics over the Access Grid.
Other capabilities. Over and above these components, the Envision
Center also features a variety of elements such as high-resolution displays
and portable stereo displays that can be used in classrooms to enhance instruction
through the use of stereo graphics, sensing and haptic devices (a haptic device
allows a user to interact with a computer by receiving tactile feedback), nano-manipulation
haptic devices, and other high-performance computing resources. These elements
allow researchers at the Envision Center to focus on pure research activities
also. For example, at the recently concluded Measured Response Workshop organized
by the Purdue Homeland Security Institute (www.purdue.edu/DiscoveryPark/phsi), researchers at the Envision Center unveiled a new type of large,
high-resolution display that promises a wide range of immediate applications.
Future Directions
How do students who have been a part of Envision react to
the experience? One student participant pretty much summed it up: “Doing
this has really taught me much more than anything I’ve learned in class.”
And in fact, an important goal of the Envision Center is to provide such real-world
research experience to students grounded in critical examination of various
scientific concepts learned in the classroom. To this end, the Envision Center
is continuing to explore the possibilities of linking classroom education with
real-world research efforts. Students currently enrolled in various courses
at Purdue, including courses such as Introduction to Augmented Reality, continue
to team with researchers to produce classroom products that have direct and
immediate use as mainstream data perceptualization tools. The center has also
launched the new program, Envision Discoverers, wherein Purdue students can
engage in informal learning about visualization tools and gain hands-on experience
with the center’s scientific capabilities—all without the constraints
(deadlines and grades) that are associated with forcredit classes. With its
myriad facets, the Envision Center expects to make a significant contribution
to bridging discovery and learning in the areas of science, technology, engineering,
and mathematics.