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Monday, October 22, 2012

paper







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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Volume 10.   Number 2.   November 2009 (Fall)

























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 edition.
        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
Distance Learning. America Society of Training and
Development: Alexandria, VA.
12.  Macedonia, M. and Brutzman, D. 1994. “Mbone
        Provides Audio and Video Across the Internet”.
       
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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