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Preparation, Authoring and
Presentation for
Distance Education with
Tango Interactive
Nancy McCracken
David Bernholdt
Northeast Parallel Architectures Center at
Syracuse University
111 College Place, Syracuse, NY 13244
• Requirements to set up Distance Education
– Focus on labs, but direct desktop is possible
– Hardware requirements
– Network Considerations
– Software requirements
• Authoring
– Preparation of materials
– Preparation for interactive tools
• Presentation
– Guides for lecturers
• The experience in using Tango Interactive for distance education comes
from two sources:
• Teaching a semester course from Syracuse University to Jackson State
University for four semesters, starting in the fall of 1997.
– This work was funded (in part) by the DoD High Performance
Computing Modernization Program at the U.S. Army Corps of
Engineers Waterways Experiment Station (CEWES) Major Shared
Resource Center through Programming Environment Training
(PET) through contract DAHC94-96-C-002 with Nichols Research
– Curriculum development was largely funded by the College of
Engineering and Computer Science at Syracuse University.
• Training courses from Syracuse University and Ohio State University.
– This work was also funded (in part) by the DoD High Performance
Computing Modernization Program.
Hardware Requirements
• Lecturer’s workstation(s): Can be either one or two machines.
With two machines, one can handle course materials and the
other can handle audio/video.
• At the recipient site,
– students can have each have their own workstation receiving
course materials and handling audio/video streams. (requires
the most network bandwidth)
– there can be one workstation receiving course materials and
displaying them on a large screen and handling the
– Recommended for each student to have course materials and
audio, with only one video per lab.
– Issues about microphones at workstations are quite tricky and
will be covered in more detail elsewhere.
A good well-tested audio system is crucial!
NPAC/JSU configuration
• The network is a combination of DREN and Internet.
JSU Proxy
Student’s View of
Curriculum Page
Java Tango
URL of
Curriculum Page
View of
m Page
Audio/video stream
Participants at JSU
Teacher/Lecturer at NPAC
Network requirements should be considered carefully.
– Minimal bandwidth requirements per stream for
TANGO: Audio 13kb/s, Video 15 kb/s, Courseware 120
• Audio: instructor’s workstation sends one stream to
each BV audio client. If students use headsets, this is
one client per student.
• Video: transmitted point-to-point like audio.
• Courseware: the web server delivering slides/pages to
student browsers. This will be point-to-point, unless
the lab has a proxy web server.
• Check network configuration to see how sites are connected.
Be prepared to call network provider companies if routers
are not behaving properly.
Network Considerations II
• Calculate bandwidth requirements. E.g. a T1 line (1.5Mb/s) can
carry 100 a/v streams or 10 simultaneous course pages in the
absence of any other traffic.
– But this is quite misleading as critical issue is quality of service
– A few missed audio packets and the lecture is a write-off
– So in unclear (to us) fashion “buy” quality of service with
• Best to have one person responsible for monitoring these issues
– Are clients alive
– Is A/V correct
– What fraction of packets are dropped
– Is routing strange ….
• Limited System Support
Software Requirements
• We recommend that all recipient sites set up a proxy
web server with caching capability, such as Netscape
Proxy server.
• If possible, all sites should use the same version of
Netscape Navigator. This helps to minimize Tango
interactions with browser-specific bugs.
• Use a robust HTTP server to provide the course
materials. Our experience suggests that some servers
(Netscape Fast Track and Microsoft Peer Web Server)
will hang during a typical class. The free HTTP server
from Apache has been robust.
Testing - 1, 2, 3!
• The most important thing about your
configuration is to thoroughly test it with
each Tango tool that you are going to use
before class.
• Agree in advance which Tango server and
interface you are going to use. Be sure to
mention which time zone the test will take
place in.
• Best to have dedicated support staff always
Authoring Lecture Materials
• Almost any materials on the web can be shown through the Tango
Shared Browser.
– Documents prepared in an authoring tool such as Microsoft
Word or PowerPoint can be saved as HTML and placed on a
web server.
– Any other web pages that contain information with the
following limitations:
• Shared Browser cannot show pages with nested frames or
new browser windows.
• Other pages that are not designed for this kind of viewing
may have images that take too long to download, or type
fonts that are too small, or other characteristics not suited
for classroom use.
• WebWisdom is another set of tools (database and DHTML
rendering) to enhance documents prepared for the web.
Lecture Slides (such as PowerPoint)
• The same rules apply as for regular classroom use as far as
making slides clear and visually appealing.
– Type font sizes in the range of 20 to 24 pts.
– Diagrams and images are nice.
• But there are other restrictions due to the fact that each slide
must download to both the instructor and students over the
– Although dense slides are not good in general, try to put
enough information on each slide so that you don’t have to
change slides too often! (Avoid slide backgrounds that take
up 1/3 of each slide with the background image!)
– Slides with large images will take longer to download.
Showing Diagrams
• Tango Interactive has two drawing tools:
– Paintbrush - this is a very simple drawing tool, but is fairly
fast. Nancy uses it to draw diagrams on-the-fly during class.
She can even draw equations with symbols like “capital
– Whiteboard - this is a fully functional drawing tool with an
arcane interface. It is slower because it allows you to change
all sorts of drawing properties with popup boxes. I use it if I
need to prepare a diagram ahead of time. Unlike Paintbrush,
when the students connect, what is already drawn will show.
• In the future, you will be able to load previously drawn
– Both drawing tools allow all participants to draw, so you
must warn students not to draw on your diagram!
Guidelines for Instructors
• It is important to practice the delivery of TANGO-based
classes until you are comfortable with the tools and windows.
• One of the biggest differences that you will experience in class
is the lack of feedback from facial expressions of students.
• Expect distance classes to move a little slower than local
classes. There is more transition time and words must replace
gestures and body language.
• The audio quality typically used in TANGO is roughly
telephone-quality sound, not broadcast quality. You should be
careful to speak clearly and perhaps a little more slowly than
with a face-to-face class.
• At the moment, there is no pointer, so whenever you would
point to a place on a slide, you must describe it in words
More Guidelines
• Try preparing a script for the class with the URL’s
that you are going to use, descriptions of
diagrams, etc. Ahead of time, you can put URL’s
in the Shared Browser and draw diagrams in
• Try to keep to a straightforward logical flow.
Don’t try to back up slides (time consuming) or
make verbal digressions (confusing).
Attention Factors
• Our experience is that the attention of remote students
wanders more easily than in face-to-face classes. Probably
because there is less stimulus and sense of connection with
the instructor
– Make course materials colorful and visually interesting
– Try to make things more interactive: switch tools, have
web pages that students interact with.
– If possible, ask questions with audio. Without that, you
could give opinion polls and quizzes. Nancy prepares
ahead of time a web page with a form with the
• It is helpful to have a mentor/support person at the
delivery site. This person can help monitor student
questions, assist with the chat, and so on. Talk to them
before class to plan roles.
Interaction Issues
• If students have headsets, pause every so often to ask for
questions - even with classroom video, it’s hard to see when a
student looks like they want to ask a question.
• If you’re using chat for questions, pause every so often as well.
Furthermore, set up a separate chat for student questions and
for support personnel conversations.
• Don’t have long periods of silence. The students always think
that the audio must have crashed. If you do have to be silent for
a while, such as typing something into the support chat,
announce that you’ll be away for a little while.
• Conversely Instructor gets worried if no action from the student!
– Use Chat rooms to immediately flag errors
– New JavaScript Shared Browser monitors which page each
student is on -- especially useful if dedicated support staff to
Some Futures
• We also use a tool called WebWisdom to that enhances
documents from tools such as PowerPoint to HTML and that
has special properties in use with Tango.
– There is a pointer hand that the instructor can use to
point with.
– This tool should be publicly available in the near future to
prepare documents.
• Tango2 has a clearer user interface which should lead to
fewer errors
• There will be multicast versions of BuenaVista to be able to
set up improved audio/video streams to multiple sites.
• There will be on-line quizzes and interactions.
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