Global Warming!!!

 Lets see...Most of you must be knowing why global warming is caused..but i will go on and give a gist of it...

Gases such as Carbon dioxide , Methane etc let short wavelength infrared radiation pass through the atmosphere ( heat from the sun ) but contain long wavelength infrared radiation ( radiation emitted by earth (or any object) after heating up) , basically it acts like glass lets heat in but doesn't let it out.Hence these gases are called Greenhouse gases since its behavior mimics a Greenhouse.

Now it can be understood that as the concentration of greenhouse gases in the atmosphere increases the temperature of earth increases. So bascially our major job is to decrease the concentration of greenhouse gases and the planet can be saved??? No, there are two more major factors which enchances the global warming effect , basically these are positive feedback loops i.e. the input is dependent on the output positively,the more the output implies more input which further implies even more output and so on.

Positive Feedback Loop 1:
Now the north pole and the south pole are the two places which receive continuous 24 hr sunlight during the summer and the winter respectively.Antartica is basically a big mass of ice and the arctic ocean is almost always covered by frozen sea ice. Now these ice act as mirrors and reflect 99% of incident radiation back to space , unlike water which absorbs most of the incident radiation.
Hypothetically if both the poles did not have ice , then the solar radiation (heat) would have been absorbed by the sea , its temperature would increase which would eventually increase the average temperature of earth. (since oceans cools the land , all the trade winds etc originate from the oceans).

Okay... now what is happening is that Greenhouse effect is increasing the average temperature of earth.This causes the ice in the polar caps to melt which in turn reduces sunlight reflected by ice and increases the sunlight absorbed by water.This in turn increases the temperature again.As u can see this is the positive feedback i was talking about. Ice melts->water absorbs sunlight->temp increases->ice melts.

Thankfully for the above positive feedback to become self sustaining there has to be an initial threshold.

The initial threshold maybe the average temperature or the amount of ice left on Antarctica.It could be  anything and we have no way of finding out (scientists are running advanced weather models to find out the exact threshold and have been unsuccessful till now). Once this happens consider our planet's climate system would go out of control.
Okay now on to the second feedback loop..

Positive Feedback Loop 2:
We all know that most of Greenland is covered with ice. But underneath that ice are massive reserves of Methane ( Natural Gas ). Now as the ice melts, methane leaks out into the atmosphere.As you know Methane is one of the major greenhouse gases.Again a positive feedback loop has uncovered itself.

Ice melts->methane leaks->green house effect..temp increases->ice melts->and so on

Hence Global warming is a result of Greenhouse effect and the two feedback loops mentioned above

Our present carbon emission rate + both the positive feedback loops.We are looking at an avg increase in 2 to 3 degree from a optimist's view and an increase of 6 degree's from a pessimist's view in the next 10-20 years.

So i suggest all of the readers to GO GREEN!!

P.S. About the methane leaking thing, there are several videos of it. Scientist's light the jet of methane leaking out of ice (:D).Looks really cool , check it out on youtube. :)

AI : Are we on the right track?

The question of intelligence is the last great frontier of science. Will we ever be able to build a machine that is intelligent enough to come up with a joke or a poem? Will it be able to understand sarcasm and have consciousness in the same sense humans do? How is it possible for the brain, whether biological or electronic, to perceive, understand, predict and manipulate a world far larger and more complicated than itself? And if this is possible, are we on the right track?

Unfortunately there seems to be a very fundamental difference between the current algorithmic way in which we look at AI and the way the brain actually works. The biologists seem to reject or ignore the idea of thinking of the brain in computational terms, and computer scientists often don't believe they have anything to learn from biology.

For the first few years, the input and the goals were all represented by sentences of some mathematical logical language. Otherwise AI programs often examine large numbers of possibilities, e.g. moves in a chess game and every possible move was examined one by one before arriving at the optimal move. Another way adopted by the initial AI programmers was to use heuristics. Heuristic functions are used in some approaches to search to measure how far a node in a search tree seems to be from a goal. The optimal node would therefore be the one that returns the maximum value when substituted in the heuristic function.

Unfortunately, these methods have many practical uses but they don’t come anywhere close to mimicking the way the human brain works.

The brain seems to be continuously building a model of the world around it by taking sensory input from the eyes, ears, and other organs to record memories of our experiences. New experiences and inputs are then compared to previous memories within this model and a prediction is made. The success or failure of these predictions, as well as new experiences are continuously fed into the brain so that it continuously evolves and self modifies is model of the world. It seems to work very much like a control system with feedback.

According to me, neural networks and genetic programming seems to be the two best bets for AI among the present set of theories. The approaches to AI based on neural nets comes close to mimicking the predictive model of the brain. A neural network with Hebbian learning can be viewed as a prediction machine. Genetic programming is a machine learning technique used to optimize a population of computer programs according to a fitness landscape determined by a program's ability to perform a given computational task. But programs can only learn the facts that can be represented by their ‘formalisms’, and unfortunately learning systems are almost all based on very limited abilities to represent information.

According to Turing, in a conversation with an ideal intelligent machine, the human will not be able to tell whether he or she is talking to a human or a machine . Aeronautical engineering texts do not define the goal of their field as 'making machines that fly so exactly like pigeons that they can fool other pigeons.' Clearly, there seems to be something very fundamentally wrong in the way computer scientists look at AI.

Why should Google be interested in cab companies?

You’re new to the city and plan to go to a movie theatre on a Saturday evening. You have no idea where this theatre is because chances are you’ve booked the tickets online. So you do what anyone with a computer and an internet connection would do. That’s right ...Google Maps. You go through the drill ... point A, point B, get directions and you have it, the shortest path, the distance and expected time right in front of you. There’s just one problem, I think in our cities we need to start measuring how far places are in terms of time rather than distance. But doing that conversion requires knowledge of way too many parameters like time, day of the week, road conditions, traffic patterns, weather, construction projects and even events like political rallies, festivals etc all of which vary from place to place.

Well the problem and the causes are pretty obvious, what we need is a cheap and effective solution, cheap being the keyword. One thing that is common between every street in every city is the ubiquitous TAXI. Recently, in India, we have seen private companies entering this business. The interesting thing is most of the taxis owned by these companies are equipped with a GPS. Basically, if you look at it another way, you’ve got thousands of these GPSs crawling all over the city’s roads 24*7 and that is going to generate a lot of useful data.

Here is how it can work, all the data from the GPS’s is uploaded to a main server. This effectively gives you a snapshot of the city map with lots of dots corresponding to positions of all the taxis. Now let’s take these ‘snapshots’ at regular intervals (let’s say every 2 minutes). Comparing successive snapshots, find how much every dot on the map (or taxis) moves in the 2 minutes.

Then we use that wonderful equation that we all learned in 2nd grade. Speed = distance/time. That’s it!!
Here is a sample of a simple city and two taxis that gives us the instantaneous speed for two streets

                                At 7:00 pm                                   At 7:02 pm

Do this for the whole city and you now have the average speed of traffic on every city road at that instant. Now if you do this, let’s say at 7pm on a Wednesday then it’s pretty obvious that these values of speed would hold good every Wednesday at 7pm.

That brings me to the next part, if the above calculations are repeated every 2 minutes for an entire year; you would get a good idea of variation in average speed over the year (for e.g, streets in low lying areas would show a drastic reduction in the rainy season). That takes weather out of the equation. 26th July 2010 will have the same weather pattern as 26th July 2011. Basically the longer you observe, more patterns start showing up.

One instant: road conditions
One day: rush hour traffic pattern
One week: daily pattern i.e. weekends vs weekdays
One year: weather patterns

Additional features
A graphical representation of avg. speed data would show congested roads (low avg speed) in red, clear ones in green..etc. Once you have a good database of traffic patters, say after 2 years or so, a time varying traffic map can be made. You drag a pointer on a timeline and the map varies accordingly.
Once, this is achieved, the applications could be huge. Other than obvious ones like traffic management and city planning etc there are environmental benefits as well.

Down to business
Isn't it always about the money? More often than not, for something to work, someone needs to make a lot of money out of it. Who pays for the server setup, the software applications, system maintenance, the GPS etc?


An interested group would be real estate developers (to do a quick analysis of how convenient a place is). Railways could adjust train timings to suit traffic flow. In the future, if we are able to make smart cars, their developers would certainly be interested in data like this. (I'm allowed one lame example). But, imagine a car that downloads data from one of these servers about the route with the best traffic flow and then drives you through it.

On a more serious note, here's one scenario, cab companies agree to share GPS data with let’s say, Google for a hefty fee. Google then uses this data in its maps application to give you a very good estimate of TIME taken to go from your home to the theatre based on data collected on a Saturday evening last July and you find out, the “shortest” route is not that short after all.

What’s in it for Google?
It adds relevance to Google map’s results as they now take into consideration local factors

What’s in it for the cab companies?
Money out of nothing!

Simple linux tweaks!!

Changing the Boot sequence!!

Here is a noobish but useful tip for people having more than 1 OS. When we install linux after windows, the default OS becomes linux. To change this sequence follow the steps given below.

• Go to root->boot->grub->menu.lst
• sudo chmod a+w menu.lst
• change default 0,to the line no of the preferred OS.

Creating .deb file

After .\config

Instead of make install do check-install or sudo apt-get install checkinstall

.deb is created in source dir.

GRUB 17 error

I have had this error 17 many times from having bad power downs and crashes for other reasons. In most of my cases the problem is usually from a bad magic number in the root partition. This can be easily fixed by doing this:

a. boot from any live CD (ubuntu install disk works for me)

b. open accessories->Terminal

c. in terminal type "sudo e2fsck -b 32768 /dev/hdaX

replace the hdaX in line above with the disk that you have your root mounted from

for example sudo e2fsck -b 32768 /dev/hda2

in my case I have windows installed in /dev/hda1 and my root partition for ubuntu in at /dev/hda2 also if -b 32768 fails you can try other numbers including -b 8193 or -b 98304 or -b 163840.

• if u want to prevent ubuntu 4m asking passwd everytime ..jst run visudo app..and add ALL=NOPASSWD: ALL

VLC with compiz

• Start VLC and click on Settings, then Preferences.
• Expand Video and then expand Output modules. You will notice several options for output device.
• Select the item Output modules, and notice the checkbox at the bottom right that says Advanced options.
• Check the box, and now you have the option to select a different output device.
• Pick X11 video output
• Click on Save and you are set!

Google chrome OS : Pros and Cons

Pros :

Speed: Currently, boots up at around seven seconds. Google is trying to make it faster!!

Ease of use: Almost everyone knows how to use a browser can use chrome OS.

Low system requirements: With all work being carried out on the web, the hardware requirements are not likely to be very high.

Cloud gains: Storing data on the cloud means that you can access it from just about anywhere.

Applications: Anything that runs on the web will run on the Chrome OS, says Google.

Cons:

Multimedia: It is unlikely to handle heavy-duty video and audio the way Windows and Macs do.

Security: The jury is still out on just how safe the cloud is.

Applications: Web applications are generally poor cousins of their desktop counterparts.

Accessories: Just how many devices will work with Chrome OS? No one knows right now.

Bandwidth: With so much depending on the web, what happens when net gets disconnected?