Implementing a Desktop Video Conferencing
Technology for Effective Teaching
and Learning.
ABSTRACT
The traditional
teaching method has
brought about a lot
of inconveniences on
the part of students
and lecturers in our tertiary institutions. These inconveniences include travel costs on the part
of students to
reach lecture venues, inadequate and congested lecture rooms, and so on. The
necessity for the
modification of this
teaching method
brought about video
conferencing
technology, which is
a means whereby a live
connection among groups
of people
or individuals in
separate locations is made possible for the purpose of
communication and sharing
of computer application
for collaboration in real
time.
This paper examines the objective of designing
software
that would anchor
desktop video
conferencing effectively and
efficiently. The
features of the software include transmission
of
video signals, audio signals, data properties and
coordination of the
conferencing session. The
software
would be integrated
on the hardware
which includes a camera (visual capture device),
microphone (audio input device), speakers
(audio
output device), video board (visual interface on
system), network card (network
interface on
system and the computer system. The
technology is
web-based and implemented
on a network. This would
enable people participating
in the video conferencing
session to see,
hear, and collaborate effectively.
(Keywords: video conferencing, networking,
workstations, LAN, Mbone software, controller,
processor)
INTRODUCTION
The
rapid growth of
computers in the
modern
world
has been brought
about by one
unique
aspect,
which is networking.
Networking is the
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interconnection
of two or
more autonomous
workstations or nodes together for the
purpose of data
sharing, resource sharing,
communication sharing, and process
reliability. The increasing advancements in networking
technology brought about the
development of video
conferencing, which has
been a very
important technology development in the learning environment.
It is a means whereby a live connection among
groups of people
or individuals in
separate
locations
is made possible
for the purpose
of
communication and
sharing of computer
applications for collaboration in real time
(Callum,
2000). This is more or less a typical synchronous
conference.
By synchronous, we
mean the
students and lecturer are engaged in the class
simultaneously in
such a way
that the classic
teaching
synergy of question
asking with
immediate response is a fundamental part of the
educational process. An audio, video, and text is
used in video conferencing environment
enabling
both parties to see, hear, and present
materials
as if they are in the same room. The
growth of
network technology and in
particular, the internet,
has led to a greater awareness of the potential of
conferencing system
for teaching, collaborative
work, assessment, and student
support (Burns et
al., 1996).
The
traditional teaching methods
in which
lectures
are delivered face
to face and
with
physical presence of both parties (lead
teacher
and
students) is quite
different from video
conferencing.
So using video
conferencing
technology
does change the
normal teaching
environment
and this can
cause concern for
tutors
and students alike.
Although video
conferencing
is trying to
adopt the traditional
teaching way expect for the technology involved
and the physical presence of both parties
which is
not required. Lectures are seen on screens and
visual
display. However by
approaching the
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possibilities
offered by video
conferencing in a
positive manner, the learning experience can
turn out to be successful for all concerned (Burns
et al, 1996).
Video conferencing involves the use of hardware
and software for its full architecture. A
complete
simulation will enable both parties, which are the
students, and lectures to see, here, and
present
materials just as if they are same room (Callum,
2000). Organizations like banks, oil
companies (to
communicate between
onshore and offshore
personnel), manufacturing companies,
and
television stations
are also using
video
conferencing these
days to carry
out some
specific task.
OVERVIEW OF VIDEO CONFERENCING
Video
conferencing is more
or less bringing
lectures to one’s doorstep. As earlier stated
it is
quite similar to
the traditional classroom.
The
instructional options available to a teacher
in a
videoconference classroom are similar
to those
used in a traditional classroom. Small
and large
group
work, demonstration laboratories,
and
lectures are just a few ways that teachers deliver
content and students engage the material
(Mason
and Davis, 2000).
Video conferencing
is a vital
tool used for
personal communication, which include informal
and formal meetings, collaborative work
between
researchers using
shared applications,
presentations and education.
Delivering
a lecture on
the day’s subject
is
appealing because a teacher can get through
the
entire lesson and eliminate the time-consuming
work
of facilitating numerous
groups or
demonstrations. Lectures are an effective
means
of delivering information to students at all
sites
during
a one-time-only video
conference or in
combination
with more engaging
activities.
However, lectures can be counterproductive for
both teachers and students if they are used as
the
primary mode of instruction throughout
a
videoconference course.
An
interactive model of instruction allows students
to
actively participate in
the lesson through
demonstrations, small-group discussions,
laboratories, writing, and presentations.
Activities can be done “live” during the videoconference or after the videoconference.
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Preparation
considerations and production
time
increase
when a class
is more interactive. Coordination
with teaching with teaching partners and students
at receiving sites
is the key to
managing class time effectively and
delivering the essential parts of the lesson.
Combining
lectures with activities
ensures that
important
material is covered
while engaging
students
and giving them
hands-on experience
with
concepts. The production
needs of a
combined lecture/interactive approach vary
based
on
the kinds of
materials and participation
activities required.
It is important
to balance
flexibility with the lesson’s priorities (Mason and
Davis, 2000).
According
to Hazel (1998),
the types of
video conferencing that are practiced include:
•
Person to person (class to class / one to
one
meeting): this is the simplest form of
conferencing
where two computers
connect directly
with each other
using
conference software.
The connection
might be base on the usage of the usage
of the Internet protocol (IP) address of the
person or the users address information
as configured on the software package.
The two parties
can then communicate
over the network in real time.
• Group
conference (many to many): This
is a situation
where many people
can
participate and collaborative. To do this,
each
person or class has to connect to a
site that is
running software on
conferencing. Typing the Internet protocol
(IP)
address of the server system makes
the connection and the system receives
everything that is being transmitted by the
group and then transmits it to the others
in the group.
Broadcast (one to
many): this is
a one-way
conference
much like television
much like television.
One computer running the conference software
transmits audio and video to all those who are
connected. Satellite transmission
is usually used for
broadcast.
Figure 1: Types
of Video Conferencing Modes.
• Studio-based System: A studio
based is specially
equipped for the
video conferencing by an
organization. This kind of
conferencing can be used majority by
the
organization or leased for use for
other
organization. This will normally
include one or
more cameras,
microphone,
one or more
large
monitors and possibly other
equipment
such as overhead
cameras for document viewing.
Getting familiar with video conferencing and
its
equipment involves organizing
an introduction
session
if one is scheduled at
the operating
center. Here, a technician or an
experienced user
of video conferencing equipment will
put all others
through with
the usage of the software
and
hardware (Burns et all, 1996). This
implies that in
the introductory session, the
lecturer and students
are educated based on the usage of
the hardware
and software by the technician before
they can
now
get familiar with
the video conferencing
technology.
Desktop video conferencing is a new paradigm for video conferencing.
It is “desktop” based
which
implies that participants
sit at their
own desks,
I their own
offices and call
up other participants using their personal; computer in a manner much like a telephone.
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The rationale behind the selection of equipment
used
and their description,
operating principles and the set-up are emphasized below.
RESEARCH METHODOLOGY
Desktop video conferencing involves
technological input on whichever method is used
in setting up the system. The technology
involved
makes use of devices which include a
camera,
usually attached
to the monitor,
microphone,
speakers (either onboard speakers,
external ones
or headphones are applicable), video
board (to
capture the signal from the camera
and convert it
to digital from), and a Network
card (usually an
Ethernet card for
connection to the
Local area
network (LAN)
or an services
digital network
(ISDN) card).
In
setting up a
desktop video conferencing environment, all
of the equipment
mentioned above has to be connected to a workstation
with universal
serial port (USB) port
for equipment
without a parallel connector port. This
implies that on the workstation there must be a USB port.
For desktop video conferencing, a better
quality
signal is required to be transmitted both
for visual
and audio. So a high bandwidth (the amount of
information
which can be
transmitted every
second) is required
because audio and
video
signals are transmitted into achieve. A fast
and
high capacity digital transmission of
voice, data,
still images and full motion video are
required.
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The integrated service digital network (ISDN) or
the Internet protocol (IP) is used and this is
fast growing
because many people
already have a connection to
an existing IP
infrastructure (Huston, 1996).
The
basic work is
on the development
of software, which would be used in achieving the
setting
up of the
desktop video conferencing environment. The
software would perform
the following functions:
•
Multipoint data conferencing
• Video
conferencing
•
Internet telephony
•
Telecommuting Virtual Meetings
• Distance Learning and a host of others
For a complete set-up of video conferencing, the software would create room for the use of office packages
like Microsoft PowerPoint®
for presentation, words and
others for the database of the whole
lecture period.
Finally, setting up a desktop video
conferencing
via
the broadcast method
requires the above-
mentioned
hardware already set
up on the
systems required for
the conferencing. The
broadcast
set up requires
a camera to be
installed on the lecture system, which serve
as
lead
unit for other
system. With this,
all other
workstations can see the lecturer but the lecturer
cannot see them (broadcast video
conferencing).
Then the software is installed on the workstations
and
the control system
so that communication
can occur in real time.
COMPONENTS
OF A DESKTOP VIDEO CONFERENCING
The components of a desktop video
conferencing include
the hardware and
the software components as earlier
mentioned. Both the features of
the hardware and
software are enumerated below.
Hardware Components: Hardware
component
used
in desktop video
conferencing can be
grouped into Viewers, which include monitors
and
speakers; Senders, which
include cameras,
microphones,
whiteboards, and computers;
Controllers, which include the
keyboard; Tablet,
or remote; Processors,
which include codec,
bridge or
router; Transmission media;
Carriers,
which
include wires (twisted
pair and coaxial),
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microwave
in air, satellite signals, and fiber optic
cable; and Network card or the integrated
service digital network (ISDN) card, which are used
as an interface for communication between the systems and network.
Viewers: Compressed and digitized information
sent are decoded and through the receiving
site
viewers-usually monitors
and speakers. A
monitors is used as a visual display unit and
the
sparkers are use for sound in the desktop
video
conferencing set up. A monitor is also used to
observe what the lead site is sending to
receiving
sites.
This is particularly important
while
presenting.
Senders: Senders generate analog signals that are
digitized, compressed, and
sent to distant desktop video
conferencing sites. These
might include any or all of the following:
1. Cameras capture
pictures at the
originated
site. For the desktop
conferencing, a set camera that are not
moved around the room, mobile cameras,
or document cameras
that work like
overhead projectors might be used. A set
camera is the most preferable device to
be used. It
is fixed on
the monitor for
direct capture of the lead teacher.
2. Microphones capture sound. There are a
variety of microphone designs that work
best under specific
conditions. A
microphone with
the conditions that
works best under
desktop video
conferencing
is used. It
might be a
headpiece
microphone or and
ordinary
microphone.
3. Whiteboards
allow lecturers to write like a
chalkboard,
but do not
generate chalk
dust that can impair video conferencing
equipment.
The whiteboard might not be
required in the context of this seminar.
4. Computers, screens
and data form
computers
can be exchanged
between
sites.
Computers used for
presentation
should have lots
of random access
memory (RAM) and processing
[power
because of the
number and type
of
applications as seamless as possible. It is
best to use a computer dedicated to the
video
conferencing system that
is
separate
from the codec. The advantage
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to having a dedicated computer is that if
an
application crashes the
computer, it
does not
crash the codec. A codec crash
will result in the loss of communication,
and may necessitate rebuilding the codec
in order to re-establish communication.
5. Network card.
Usually an Ethernet card
for connection to the LAN, or an ISDN
card is also
present on the
computer
because it makes
communication
possible.
Controllers: Controllers
are interface devices that
interact with software and allow you to control the video conference. The keyboard, tablet and pen, and remote control are the most common interfaces. They all allow lecturer to control such
things as camera angle and zoom,
microphone volume, putting a picture
in a picture, which video feed will
be sent to
receiving sites, which receiving sites will be connected through a bridge or router, and transfer of files.
Processor: Codec. The
codec converts analog data
to digital from,
and digital data
to analog form. A codec that converts analog data to form
may
also “data, by eliminating
redundant
information,
which reduces the
amount of data
that needs to be sent for the video
conference;
another codec that converts digital data to
analog
form may “decompress” such data. The codec is
loaded on the computer associated with the
video
conferencing system at the lead site.
Its job is to
convert analog or digital signals
and to compress
the
digital signals so
that they can
be sent
efficiently. It also
decompresses and decodes
incoming signals so that they can be viewed.
This
reduces the
bandwidth needs of a video
conferencing system and
thereby speeds up
transmission.
A video conferencing is impossible if the
codec is unable to decode signals from another system. This is why it is important to make sure that all codec used for a given video
conference are compatible.
Bridge or
Router: The bridge or router connects
the participants in a desktop video
conferencing
to one another. The bridge or router is
normally
located away from the lead site and is
operated
by a separate entity. The lead teacher must
make
sure that people who are responsible for
bridging
or
routing sites into the
conference have been
notified and that they make the connections.
Figure 2: Video
Conference Hardware Set Up.
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Figure 3: Mbone
Teaching Configuration.
Figure 4: A
Typical Net Meeting Software Display.
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Figure 5: Desktop
Video Conferencing Configuration.
DESIGN, IMPLEMENTATION AND TESTING
The design of a desktop video conferencing was carried out by
applying the networking concepts, hardware
implementation and software utilization. The software package design for the purpose of the desktop video
conferencing would be able to perform some major functions as required by the desktop
video conferencing process.
The program is written using
java scripts.
The
first module of
the program captures
the
video and audio signal and stores it in a file
for
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playback. It is stored in the AVI file format and
can
be played using
the media player.
It is designed to have an interface which can stop or continue to capture as required.
In
the figure below,
it can be
seen that the specification of
the captured video
streams is 160x120 and the
format which it
is being captured. Also the audio specification is given a choice to select which of the mode he wants in both the video and audio
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Figure 6: Capture
of Video and Audio Signal.
In the
second module, the
capture video and
audio
signal is being
transmitted from the
lead
sight to the receiving end. As earlier
started, the
specification of the internet protocol address
and
the port number of the receiving end is
specified
in
this module. This
enables for easy
communication
between the lead
sight and the
receiving
end. The transmission
is done in a
fraction of microseconds because it is a real time
synchronous process.
The third module of the program concludes the
video
conferencing session. In
this module the
transmitted streams are
being received at the
destination. The address of the lead sight is
also
specified here for
the package not
to be lost
during transmission. Here the coordination
aspect
is being handled.
PERFORMANCE OF
THE DESKTOP VIDEO SESSION
In
determining the bandwidth
of the audio
and
video streams, and the one-way streaming used,
the following information were required and
used:
1. The number
of simultaneous users
that
will be on the application at peak load.
2. The connection
rate of the
users
(students)
to connect and
what
percentage
of your users will be on a 56k
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dial-up connect, on LAN, or Cable.
3. The number of
audio/video stream that is
on the application per user.
4. The limitations
as regards internet
connection.
5. The target
encode rate of the audio and
video streams in your application.
The application is a one-way video. The lead
site will serve only stream to the user.
BANDWIDTH CALCULATIONS
Lead site bandwidth:
BW1= N * S
N = Number of simultaneous student which is
1 S = Stream encoded at constant kbps
On the local
LAN, stream encoded at constant
kbps
is 10kbps.
Calculating the available
bandwidth at the lead site for a workstation
gives 10kbps.
Calculating receiving site bandwidth needs
BWr = S
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S = A/V content encoded at constant kbps
Also the stream encoded at the receiving end
is about 10kbps for the local LAN
It
should be noted
that for audio
and video streaming,
each user consumed 400kbps of
information and it is a lot of bandwidth and
in fact, too
much for a
local LAN user
or on dial-up modem or, in
some cases, even on DSL. Users connecting to this application
with connections less 400kbps will most likely encounter pauses for rebuffing and other poor quality effects.
Once the bandwidth strategy is in place, then the
performance of applications that involve
video and
audio tend to be very CPU intensive.
Once the
CPU becomes stressed, video and
audio packets
may be lost, and the CPU can
effectively handle
the performance which is measured by
the degree
to which the system adequately meet
the demand
of its assigned tasks.
The
parameters used to
measure the performance
hardware configuration of
the desktop video conferencing include.
1. Mean Time
Before Failure. This
is a
measure of the
expected time between
conjunctions
of events that are agreed to
constitute a failure. This determines the
reliability of the system.
MTBF
= (1/no of element) x (1/failure
rate)
2. Mean Time To Repair and
Mean Time To
Detect: The MTTR is the measure of the
expected
time required to
covert those
effects which has
been agreed to
constitute
failure and MTTD
is the
measure of the measure of the expected
time to detect failure.
CONCLUSION AND RECOMMENDATION
From the foregoing, a video conferencing system
can
have an important
role to play in bringing
together staff and
students across different
institutions,
bringing in outside
experts from
industry and
reaching and supporting
remote
students, either in the local
community or those
based overseas.
The
special feature of the coordination session in
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the software used also makes it more efficient.
Apart from the transmitting of video signal,
audio
signal, and data, the interactive session between
the students and lecturer; ability of the lecturer to
identify which area of the course is
difficult for the
students to comprehend.
This feature enables
the student to have a better understanding
of the
course.
The levels of
comprehension of the
technology involve in the usage the technology
has
gone a long
way in helping
the users to
improve their skills in various areas. This is
why
implementation in our immediate environment is
a necessity.
The following recommendations were
enumerated based on this project.
•
Rather than implementing this set up on
the local area network, a network mode
like the asynchronous
transfer mode,
ATM can be used for better transmission
of the audio
and video streams
which
require a high bandwidth.
• The
software can be expanded to handle
more than a
student and to
provide
adequate
coordination among the
participants in the conferencing.
A coder/decoder can be used for compression
and coordination in place of the operating
system
used
for the compression
to improve on the
efficiency.
REFERENCES
1. Wall Street Journal. 1995.
“A History of Video
Conferencing Technology”. Wall Street Journal.
http://www.spiffy.ci.uiuc.edu/~kline/cvk-ido.html.
2. Callum, D. 2000. “A Guide to
Video
Conferencing”. A video conferencing journal. 17th
December 2005. http://www.whatis.com.
3. Burns, J., Lader, R., Ryan,
S., and Wragg, R. 2-
2007. “Practical Guidelines for with Video
Conferencing”. http://www.cse.dmu.ac.uk/~jtb/jtab-037.
4. Mason, S. and Davis, M.
2000. A
Teachers guide
to Video conferencing, 1st edition. Northwest
Regional Educational Laboratory: Portland, OR.
5. Hudson, R. 1996.
’Introduction to Video
Conferencing”. 13 January 2006.
http://www.visc.vt.edu/succeed/dt/video
conferencing/.
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6.
Barron, A. and Orwig, G. 1997. New Technology
for Education. A Beginner’s Guide, 1st
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Libraries Unlimited: Englewood, CO.
7.
Collins, B. 1996. Tele-Learning
in a Digital World,
2nd edition.
International Thomson Computer
Press: London, UK.
8.
Minoli, D. 1996. Distance
Learning Technology and
Applications, 1st edition. Artech House: Boston,
MA.
9.
Porter, L.R. 1997. Creating
the Virtual Classroom.
Distance Learning with the Internet, 1st
edition.
John Wiley and Sons: New York, NY.
10.
Taylor, A. and Merabti, M. 1995. A Review of
Multimedia Networking. Advisory Group on
Computer Graphics: New York, NY.
11. O’Neil, M. and McHugh, P.
(Eds). 1996. Effective
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Macedonia, M. and Brutzman, D. 1994. “Mbone
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IEEE Computer.
ABOUT THE AUTHORS
Afiss
Emiola Adebowale Kareem holds
a
B.Tech. and an M.Sc. in Computer Science from
the
Federal University of
Technology, Akure,
Nigeria
and University of
Ibadan, Nigeria,
respectively.
He is a
Chartered member of
Computer Professionals
(Registration council) of
Nigeria. He is also a member of Nigeria
computer
society (NCS).
He is an
Associate Member of
Nigeria Institute of
management (Chartered)
(NIM). His research area is in mobile computing,
Internet programming, software tools
development,
computer communication and
networks and management of ICT
Infrastructures.
SUGGESTED CITATION
Kareem, A.E.A. 2009. “Implementing a Desktop
Video
Conferencing Technology for
Effective
Teaching
and Learning”. Pacific
Journal of
Science and Technology. 10(2):419-428.
Pacific Journal of Science and Technology
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