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NS 2 - Tutorial for beginners 2

NS2 program for simulation of TCP packets in a network set ns [new Simulator]

set nf [open out.nam w]
$ns namtrace-all $nf

set nt [open out.tr w]
$ns trace-all $nt

proc finish {} {
        global ns nf
        $ns flush-trace
        close $nf
        exec nam out.nam &
        exit 0
        }

set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]

$ns duplex-link $n0 $n1 10Mb 10ms DropTail
$ns duplex-link $n1 $n2 1Mb 10ms DropTail
$ns duplex-link $n3 $n1 10Mb 10ms DropTail

$ns duplex-link-op $n0 $n1 orient right-down
$ns duplex-link-op $n1 $n2 orient right
$ns duplex-link-op $n3 $n1 orient right-up

set tcp [new Agent/TCP]
$ns attach-agent $n0 $tcp

set ftp [new Application/FTP]
#$ftp set packet_size_ 4.5Mb
$ftp set interval_ 0.05
$ftp attach-agent $tcp

set sink [new Agent/TCPSink]
$ns attach-agent $n2 $sink

$ns connect $tcp $sink

$ns at 0.3 "$ftp start"
$ns at 3.0 "finish"

$ns run





NS2 program for simulation of UDP packets in a network set ns [new…

NS 2 - Tutorial for beginners 1

Explanation for a Simple ScriptStep 1: To start we have to set a few variables like simulator object, trace file and object, nam file and object: set ns [new Simulator] This would set the simulator with the simulator object which is to be accessed in the script. Step 2: Then, to set the nam (network animation) file with that 'ns' object and associate with it: set nf [open out.nam w]$nsnamtrace-all$nfset tr [open out.tr w]$nstrace-all $tr This would set the trace file and would connect to the simulator. The trace file is required to analyze the various packets which are send, received type of application used etc. Step 3: Now the nodes could be set as many as you want, for loop could be used if many nodes are to be made.set n0 [$nsnode] Step 4: Creating connection for the various nodes with each other with the band width and rate.$nsduplex-link$n0$n110Mb 10ms DropTail Step 5: The nodes could be given with various orientations with this option. right, right-up and right down could be u…

Analog Communications lab MATLAB Programs

%% Amplitude Modulation And Demodulation
% Name:
%
% R.No:
%% closing and clearing commands
close all
clear all
clc
%% Initialization
fs=8000; % sampling frequency
fm=20; % message signal frequency
fc=500; % carrier signal frequency
t=[0:.1*fs]/fs; % time index
%% Message signal Generation
Am=1; % message signal amplitude
m=Am*cos(2*pi*fm*t); % message signal
subplot(4,3,1:3);
plot(t,m);
xlabel('time-->'), ylabel('amplitude')
title('Modulating or Message signal(fm=20Hz)');
%% Carrier signal Generation
Ac=1; % carrier signal amplitude
c=Ac*cos(2*pi*fc*t); % carrier signal
subplot(4,3,4:6);
plot(t,c);
xlabel('time-->'), ylabel('amplitude')
title('Carrier signal(fc=500Hz)');
%% Under Modulation
ka=0.5; % modulation sensitivity
u=ka*Am; % modulation Index
s1=Ac*(1+u*cos(2*pi*fm*t)).*cos(2*pi*fc*t);%AM
subplot(4,3,7);
plot(t,s1);
xlabel('time-->'), ylabel('amplitude')
title('Under Modulated signal(ka.Am=0.5)')…

List of Websites to get free e-books

Here follows the list of websites to download e-books for free.

1. www.bookfi.org

2. www.bookzz.org 
These two websites offer 4 to 5 free downloads per day. Best advantage is that we need not go for any sign-in process or clicking on an advertisement.

3. http://manybooks.net  
In this website, apart from downloading in pdf format, one can download in many other e-book formats.

4. www.ebookee.org

5. www.bookboon.com

6. www.gutenberg.org

7. www.books123.me

8. www.brupt.com
This website provides file in word (.doc), powerpoint (.ppt) and pdf file formats.

9. www.pdfoxy.com
This website provides books in pdf format, but we should wait for 12-15 seconds and enter a Captcha code. But no need to sign-in.

10. www.docstoc.com
This is another decent website of downloading ebooks in .pdf format, with no advertisement and no signing in.

11. www.freecomputerbooks.com
This is one of the best websites for downloading technical and professional certification related books. No sign-in, no captcha and no disturbi…

MATLAB tutorial for Begineers Part 3

click here for Part 2                     click here for Part 4

Working With MATLAB Type the following following commands in the Command Window, and observe(verify) their corresponding results  12

ans =

    12

% commenting operator in matlab
%12

a=23

a =

    23

a=23; %; is a output suppressor operator

who

Your variables are:

a    ans

whos
  Name      Size            Bytes  Class     Attributes

  a         1x1                 8  double            
  ans       1x1                 8  double            


who---- This command lists the variables in workspace.

whos----This command details the variables in workspace.


12+23

ans =

    35

12-23

ans =

   -11

mul=12*23

mul =

   276

div=12/23;
; is the output suppressing operator

who

Your variables are:

a    ans  div  mul

div

div =

    0.5217

1/2

ans =

    0.5000

2/1

ans =

     2

1/2

ans =

    0.5000

1\2

ans =

     2

%   \ is the inverted division operator a\b=b/a
2/3

ans =

    0.6667

2\3

ans =

    1.5000

3/2

ans =

    1.5000

% exponential rep…

MATLAB tutorial for Begineers Part 2

click here for Part 1 click here for Part 3



1. How to open Matlab
    Method1: click on matlab shortcut in start menu or on desktop
    Method2: for windows os ::::Press windows+R--->type cmd--->type "matlab"
             for linux os:::::::go to terminal/Konsole--->type "matlab"

Note: It is recommended not to do any action, atleast-for-a-vial, while opening MATLAB because Matlab consumes more RAM while invoking.

MATLAB tutorial for Begineers Part 1

MATLAB is abbreviation for MATrix LABoratory.

MATLAB is an integrated development environment and computer language that enables users to perform computationally intensive tasks.  The software is used for numerical computation tasks, visualization, and mathematical programming.
For more details, see http://www.mathworks.com/products/matlab.

Latest release of MATLAB is R2014a.

As the name emphasis, MATLAB considers every variable/value in terms of matrices.
MatLab vs c:MatLab is not a programming language, but it is a scripting language. In simple English, you use English-like commands in the MatLab program; whereas corresponding c program will run in the background.

So, MatLab program is slower than c program; but is more flexible and lightweight than the former. 


The latest MATLAB constitutes FOUR platforms, within its environment.
1. M-file/Script file platform
2. Simulink
3. GUIDE- Graphical User Interface IDE(Integrated Development  Envinirment)
4. Matlab APPLICATIONS


Note: