Sunday, April 23, 2006

Endsems..

I had been not able to post here as my semester end exams are going on....
So will be back when these are over.....

Wednesday, April 19, 2006

State of the Blogosphere

David Sifry posted Sifry's Alerts: State of the Blogosphere, April 2006 Part 1: On Blogosphere Growth at technorati weblog:

The State of the Blogosphere is strong. The blogosphere is over 60 times bigger than it was only 3 years ago.
The Facts:

  • Technorati now tracks over 35.3 Million blogs
  • The blogosphere is doubling in size every 6 months
  • It is now over 60 times bigger than it was 3 years ago
  • On average, a new weblog is created every second of every day
  • 19.4 million bloggers (55%) are still posting 3 months after their blogs are created
  • Technorati tracks about 1.2 Million new blog posts each day, about 50,000 per hour
The blogosphere tracked by technorati is doubling about every 6 months, as the chart below shows:


read more

Wednesday, April 12, 2006

graph plotting with gnuplot

Gnuplot is a free, command-driven, interactive, function and data plotting program.
Here i' m providing a quick reference guide for plotting graphs (as many of us don't bother to go in detailed documentation).
On Unix/Linux systems start Gnuplot by simply typing:
gnuplot

first the formal syntax :

plot {[ranges]}
{[function] | {"[datafile]" {datafile-modifiers}}}
{axes [axes] } { [title-spec] } {with [style] }
{, {definitions,} [function] ...}

To plot functions simply type: plot [function] at the gnuplot> prompt
gnuplot> plot sin(x)
gnuplot> splot sin(x*y/20)
gnuplot> plot sin(x) title 'Sine Function', tan(x) title 'Tangent'


Now for plotting data points firstly data points should be written in text file with axis ranges as columns.Data files should have the data arranged in columns of numbers. Columns should be separated by white space (tabs or spaces) only, (no commas). Lines beginning with a # character are treated as comments and are ignored by Gnuplot. A blank line in the data file results in a break in the line connecting data points. '
Plotting a graph from data file "plot.data" , do
gnuplot>plot "plot.data"

Now customizing the plot :



set xlabel "x-axis data"

# will set a label "x-axis data" in graph
set ylabel "y-axis data"

set title "x vs y"
# will set title for graph
set xrange [0.001:0.005]
# Change the x-axis range:
set yrange [20:500]
# Change the y-axis range:
set logscale
# plot using log scale
set autoscale
#let gnuplot determine ranges
plot "file.data" with lines
#will join data points with lines
plot "file.data" smooth csplines with lines
#will join plot graph using smooth curves
Gnuplot can mathematically modify your data column by column:
to plot sin( col.3 + col.1 ) vs. 3 * col.2 type:

plot 'force.dat' using (3*$2):(sin($3+$1))

To print graph (this will store graph in post script(.ps) file do this before plotting graph:

set output "graphs.ps"
set terminal postscript
plot "file.data" using lines


This will save the graph in graph.ps
For more help type 'help' in gnuplot mode :
gnuplot>help


somelinks
www.duke.edu/~hpgavin/gnuplot.html
A simple guide to GNU plot
Introduction to GNU plot

Friday, April 07, 2006

Useful Windows XP DOS Commands & Tricks

Typing DOS commands on the Windows Command Line prompt is a most efficient and faster way of doing things in Windows XP. Here's a run-down of the most useful DOS commands available in Windows XP. Some of these DOS commands even do not have an visual alternative. Digital Inspiration has a nice roundup of 10 very useful commands and tricks that can help you get things done quickly from the command line.
Useful Windows XP DOS Commands & Tricks [Digital Inspiration]

Related resources on Microsoft Website:
List of DOS Commands with Examples

Phishing

Now a days, phishing cases had increased so here is brief writeup to give insight a about phishing . Read Wikipedia to know about phising examples.
Phishing is a technique used to gain personal information for purposes of identity theft, using fraudulent e-mail, instant messages that appear to come from legitimate site. These authentic-looking messages are designed to fool recipients into divulging personal data such as account numbers and passwords, credit card numbers and Social Security numbers.

why phishing works :

  • Lack of knowledge
  • Visulal deception : Phishers use visual deception tricks to mimic legitimate text, images and windows.
    • Visually deceptive text.: Users may be fooled by the syntax of a domain name in “typejacking” attacks, which substitute letters that may go unnoticed (e.g. www.paypai.com uses a lowercase “i” which looks similar to the letter “l”, and www.paypa1.com substitutes the number “1” for the letter “l”). Phishers have also taken advantage of non-printing characters [25] and non-ASCII Unicode characters [26] in domain names.
    • Images masking underlying text. One common technique used by phishers is to use an image of a legitimate hyperlink. The image itself serves as a hyperlink to a different, rogue site.
  • Bounded attention
    • Lack of attention to security indicators: When users are focused on their
      primary tasks, they may not notice security indicators or read warning messages. The image-hyperlink spoof would ve thwarted if user noticed the URL in the status bar did not match the hyperlink image, but this requires a high degree of attention.

Techniques used within Phishing emails:
  • Official looking and sounding emails
  • Copies of legitimate corporate emails with minor URL changes
  • HTML based email used to obfuscate target URL information
  • Standard virus/worm attachments to emails
  • A plethora of anti spam-detection inclusions
  • Crafting of “personalised” or unique email messages
  • Fake postings to popular message boards and mailing lists
Preventing Phising :
  • If you get an email that warns you, with little or no notice, that an account of yours will be shut down unless you reconfirm billing information, do not reply or click on the link in the email. Instead, contact the company cited in the email using a telephone number or Web site address you know to be genuine.
  • Never respond to HTML email with embedded submission forms. Any information submitted via the email (even if it is legitimate) will be sent in clear text and could be observed.
  • Avoid emailing personal and financial information. Before submitting financial information through a Web site, look for the "lock" icon on the browser's status bar. It signals that your information is secure during transmission.
  • Before signing to a page check for URL(make sure it is valid page, there may be some deceptive text there,like i in place of l). Or yo can try first enteing wrong password so a nonvalid page (if it is accessing information and is redirecting to legimate page to avoid being caught) will redirect you to correct page.
  • Switc your browser: use one with anti-phising agent (like firefox)

Tuesday, April 04, 2006

Some Latex tips & Links

Here are some quick tips and links which you can find useful when writing some report, article in latex.

Firstly here is an nice article explaining why latex is good .
Here are some editors available for latex:
For Linux :

  • Kile : KDE Integrated LaTeX Environment
  • Lyx
  • Emacs : It's available for a couple of operating systems like Linux, Unix and MS Windows. For LaTeX you should use the quite ingenious modes AUCTeX and RefTeX. You may refer my Emacs-page for further hints.
For windows :
Getting to grips with Latex
Getting Started with LaTeX
LaTeX Tutorial : some templates here
LaTeX Tips and Tricks