Saturday, May 03, 2014

John McCarthy, Guru of Artificial Intelligence - Read about him in Resonance


Everyone in computer science knows a lot about John McCarthy and his contributions.  LISP was the first programming language I fell in love with. His contributions to AI and computer science are well-known, but I confess that I have never read his biography so far, but I caught up a bit recently when Professor V Rajaraman wrote a very interesting article about John McCarthy in the March 2014 issue of Resonance, which is available online. Visit
I downloaded the PDF version of the article and read it. As a bonus, there is another article in that issue by Dr Raman Chandrasekar on the famous AI system named “Jeopardy!” which competes in TV quiz programs:  http://en.wikipedia.org/wiki/Jeopardy!

Let me offer a few tidbits to give you a feel for Rajaraman’s article. He mentions McCarthy’s visit to IIT Kanpur and says it inspired a number of students to take up computer science and that one of them was Narayana Murthy! He also mentions that the parents of McCarthy had been immigrants to the US, one from Ireland and one from Lithuania. Both had been members of the American Communist Party.

McCarthy had done seminal work in Artificial Intelligence, brought researchers together in the beginning of work in the field; no wonder Rajaraman calls him Father of Artificial Intelligence. McCarthy spent three years serving as Assistant Professor of Mathematics at the Stanford University, but was not given tenure! I got reminded of young colleagues in India who are very interested in inter-disciplinary research of potentially great significance, but are scared that promotion committees may not do them justice if they “stray” beyond the mainstream!  

I do not wish to say any more about McCarthy’s ideas and work in this blog post. I only wanted to attract a few more readers to enjoy Prof Rajaraman article and to benefit from it.  He has done a great job of elucidating the important ideas that McCarthy had worked on.


Srinivasan Ramani 

Wednesday, April 30, 2014

Building a WiFi “Satellite”


This post is really a companion to my recent post 
http://www.obvioustruths.blogspot.in/2014/04/use-unlicensed-wifi-spectrum-in-rural.html Please read that if possible, before reading the following. It will give you the context in which I write. 


Here, I really mean by “satellite” a device or a system that is remotely located, and performs a communications relay role. It should be designed to withstand pretty harsh environmental conditions and run unattended. It should be self-sustaining in terms of power, depending on solar panels. It does not have to be in earth orbit! It would be sufficient if it is on some tall peak like Doddabetta in Ooty, Mullaiahnagiri in Chikmagalur, Anamudi near Munnar, Perumalmalai peak in Kodaikanal (just to name a few peaks in South India). If there is a tall building visible for miles around, it may even be on top of that building. The harsh environmental conditions that have to be withstood would be rain, lightning, wind force, heat and cold. 

Actually the system does not have to be on the tallest peak or building in the area, but on a well-chosen place that provides effective line of sight with suitable user groups like schools/colleges. The altitude at which it is located should help it to command a large area around. I expect that it would be easy to find many places in India, where one such device would cover a thousand square kilometers within WiFi range! The “satellite” should, of course, be mounted on a tower or something like that to prevent theft!

The system would include a router, several 5.8 GHz radios and directional antennas. It would have maintenance-free storage batteries and solar panels. Designing such a device is an inter-disciplinary engineering activity and I hope students from different disciplines would volunteer to look into the different aspects. Many design issues arise – like should we decide in advance what the user groups should be and fix the directional antennas appropriately? What is the ideal trade-off between simplicity and sophistication? I will leave to readers to find such issues and discuss them.

Srinivasan Ramani 
April 30, 2014