Compression Techniques in Multimedia System

1. What is compression technique?
The techniques used for data compression is called compression technique. Compression technique is the process of encoding information using fewer bits through use of a specific encoding scheme.
2. Significance of compression techniques in multimedia system
There is much significance of compression techniques in multimedia system. With the techniques we get less disk space for data, faster reading and writing, faster file transfer, variable dynamic range and byte order independence.
3. Coding requirements in compression techniques
The basic coding requirements for compression techniques are storage, throughput and interaction.
Multimedia elements require much more space than text element, for example one second of uncompressed CD quality stereo audio is 176400 bytes and a true color full screen image requires 921600 bytes.
Continuous media requires a large amount of processing power that is throughput like uncompressed CD quality stereo audio stream needs 176400 bytes per second.
Multimedia system requires fast interaction between the sending and receiving ends, thus end to end delay should be small like video conference needs a delay less than 50 ms.

Kerberos Protocol.. A slide on it describing it with few words

Hi all,
I have prepared a short slide on kerberos protocol: what it is and how it works.
lets have a glimps on it..
KERBEROS_Slide
Kerberos slide [ mirror 2 ]

Man In The Middle (MITM) Attack... In brief

What is a Man In The Middle Attack:
Man in the middle attack is a security attack in which the attacker intercepts and can be able to modify data that is transmitted between two users while the attacker pretends to be the other person to each user.

How this attack takes place:
In this type of attack the attacker intercepts messages in a public key exchange and then retransmits them substituting his own public key for the requested one so that the two original users still appear to be communicating with each other.
An example will make it clearer. Let, there are two parties Alice and Bob and the attacker is Trudy. Now this attack can be taken place in the following way.
Step 1: Alice says I am Alice. Trudy captures this message and passes it to Bob by pretending that this is from Alice.

Developing j2me application on ubuntu [9.04]

First Install JDK:
To install jdk, open terminal and type those commands
sudo apt-get update
sudo apt-get install sun-java6-jdk
OR,
Application---> Add/Remove application
'Show:ALL available application
Search 'JAVA' Tick and apply
Downlaod Netbeans:
Now go to www.netbeans.org and downlaod the full version of the IDE.
After downloading install it....
Thats it your ide is ready for development.
Then create new project and select J2ME and choose option start developing.
A good emulator:
Download WTK for linux from java.sun.com
Install it..
for installing wtk see this guide.[Click Here]
Now U r ready to rock.....

Installing bind9 in ubuntu 9.10

Step 1:
On the terminal the following command was issued,
sudo apt-get install bind9
Step 2:
In this step we have configured the named.conf.local file. Before editing this file we have backed it up by issuing the command,
sudo cp /etc/bind/named.conf.local /etc/bind/named.conf.local.bkup
Then we have edited the file issuing the command
sudo gedit /etc/bind/named.conf.local
After editing the file was like this,

Installing Samba in ubuntu 9.10

Step 1:
On the Terminal  the following command was given one after another.

sudo apt-get install samba
sudo apt-get install smbfs

Step 2:
For LAN now we have to set up a manual IPV4 address and other related settings. In our case our IP address is 192.168.0.1 with 255.255.255.0 subnet mask.
For setting up the IP address we have followed the steps like,
From the system menu we have selected preferences then connection and then wired. Then  there we have added the manual entry.
Step 3:
In this step we have configured the samba for our type of usages. We have used it for sharing files in a LAN.
Before editing the configuration file we have backed it up by issuing the following command

sudo cp /etc/samba/smb.conf /etc/samba/smbk.conf

Then we have configured  the smb.conf file. After the configuration the content of file looks like the following,

[global]
workgroup=WORKGROUP
netbios name=test
server string= Samba Server
encrypt passwords=yes
security=share
map to guest = Bad user
[homes]
path=/home/saiful
read only=yes
browseable=yes
[Music]
path=/home/saiful/Music
read only=yes
browseable=yes

Here the [Music] and [Home] are the shared folders on this particular pc.
Step 4:
In this step we have restarted our samba server by issuing the following command

sudo /etc/init.d/samba restart

Step 5:
In this Step we we have accessed files from both windows and our linux machine.
For accessing file from windows machine, we just enter the ip address or browse file from the network places.
For accessing files from the linux machine to an windows machine,
At first we need to press ALT+F2 keys, then into the box we need to write smb://IP_address_of_windows_machine, like smb://192.168.0.101

How to install Cisco packet tracer 5 in Ubuntu linux 9.04

U can install cisco packet tracer in ubuntu 9.04 now. For this all y have to do is to follow the following steps and u r done.

1. Download the packet tracer 5 from cisco site if u r student there [ The generic tar.gz format ] But if u r not a student then download it from here.
click this link to download
And keep the downloaded file in your home/ur_user_name directory.

2. Open the terminal and write

"sudo tar xzvf PacketTracer5_generic.tar.gz" [without the quotation mark]

Give the sudo password.

3. Now it is uncompressed. Go to your home directory and find the uncompressed folder. Enter into the folder and there u will find a file named "install".
double click on that file and a prompt will come up.
Select "Run in Terminal" option.