Saturday, October 11, 2008

Elephants and Humans

Well, in Sri Lanka at least 65 People and 150 Elephants loose their lives due to the on going conflict between them. The main reason behind this conflict is that the poor people, due the cost of land have no option but come and live in the boarder of wild life parks. Due to this reason the humans have come in to an area in which the elephants live in.

image source :

The rise of the number of deaths of humans as well as elephants has prompted the relevant authorities to come up with a so called electric fence as  a solution for the confilcit. This solution has failed to live up to its expectation. The main reason for this is that the elephants have adapted them self to the fence. It has been stated that these elephants are so intelligent that they tend to use different mechanisms to earth the electric fence. They have also had success by throwing different object in to the fence to brake it down.

Therefore, the human elephant conflict (up to date) has no proper solution for it!!!

Friday, May 30, 2008


ACQP or in other words Acquisitional Query Processing is a querying technique used in wireless sensor networks. When it comes to sensor networks, we all know it contains hundreds of spatially distributed sensor nodes which collect sensor data. Because of the distributed nature of these sensor nodes the data within them are inherently distributed.

One of the major considerations when it comes to sensor nodes is that they contain less amount of energy (battery power) and they contain very less storage. Therefore querying in sensor network environments is much different when compared with traditional query processing. With the database being distributed ACQP brings about a new dimension for query processing.

According to ACQP, querying is done on demand. Or in other words ACQP means collecting data as and when needed with specific sample rates.

As sensor networks function without human intervention for many months it is a must that the low battery energy of them is conserved as much as possible. Therefore by querying data on demand we could conserve energy on sensor nodes and also get relevant sensor data when we need them.

Wednesday, March 12, 2008

My Experience on Bed

Well gotcha naughty mind. I am not going to write anything on my experience on bed but I am here to give you all about my experience on DEB (HA HA HA :-) ) or for that matter debain based Linux distributions.

Well well well for those who know me, Surprise right? Girisha is speaking about Open source. Well it’s not because I failed my interview with Microsoft Research India or it's not because of me having any grudge over the Microsoft.I working in a lab where Microsoft products are extremely prohibited.(He He He)

From the lovely sweet world of Visual Studio and ASP.NET I have come into a world of VIM, Python, C, JSP and from the lovely world of WPF (Though I don’t know a shit about WPF) to “XServer” programming. Phew talking about some turn over right? To tell you guys the damn truth it taking me hell of a lot of time to get use to all these stuff.

Well to finish off telling you this, this experience is really getting a GEEK out of me!!!

Saturday, January 12, 2008

Bootstrapping in Compilers

Any high level language can be implemented using an Assembler. So how are the assemblers implemented.

Well primitive type of assemblers where implemented using machine code. This implies that by making a language a subset of another we could develop languages.

This process is known as BOOTSTRAPPING.

Just to explain in a much more simpler manner, BOOTSTRAPPING could be described as stated bellow.

"A simple language compiles a complicated program and this program in turn could compile a much more complicated program and so on...."

So folks thats it about bootstrapping... So for anyone of you, who still think "what the heck is a boot strapper" please don't mix it up with the boot straper in the Pirates of the caribbean (Wiliam's Father)...

Friday, January 11, 2008


Well for all of you who are wondering what is IPSec here is a small introduction to rock your mind off from what ever it is. IPSec is a security protocol which works in the 3rd layer of the OSI stack. It can ensure the following

  • Make sure that routing or a routing advertisement came from an authorized router.
  • An redirect message came from the original router where the initial request was sent.
  • Make sure that routing update was not forged.
There are two types of IPSec connections

1. Tunnel Mode
Encrypts the entier IP packet and authenticates the entire IP packet.Original IP header should be replaced by the new IP header which has the next hop router address. Slow and good for VPN's and gateway to gateway security

2. Transport Mode
Encrypts and authenticates the payload of the IP packet. The original IP packet stay intact. Faster than Tunnel mode and is used for traffic analysis purpose.

Benifts of IPSec over SSL/TSL

  1. Encrypts entire IP packet
  2. Independent of IP address
  3. No impact on security gateway to security gateway communications
  4. Protocol Independent

Pitfalls with IPSec

  1. Many way to configure and can be complex at times
  2. Can be configured in a wrong way
  3. Client security is an issue
IPSec guidelines

  1. Use SHA1 over SHA and MD5
  2. Use 3DES AES or blowfish
  3. Never use DES
  4. Tunnel mode
  5. Encrypt entire packet
  6. Use certificates for key exchange
Extracted from the lecture slides of Dr. Kasun De Zoysa. Department of Communication and media technologies, Department of Computer Science, University of Colombo School of Computing(UCSC) Sri Lanka(LK)