Friday, March 02, 2012

Kalman and two clocks

Just learnt about Kalman filters from the Udacity self-driving-car course. And was amazed about the ability of the Kalman filters to combine info from multiple sources, in a way that it always decreases the variance.

Which made me think of the old adage 'A man with two clocks is never sure'. But if it were Kalman, he'd be surer than if he had either one of the watches (even if one of them were as precise as an atomic clock and the other was a grandfather clock that needs winding).

I like my bro's version of the Kalman corrected adage: 'A man with one watch is sure about the wrong time'

A good intro to Kalman filters here. Its chapter one of a book
And the wikipedia article.

Current mood: math-y
Currently listening to: Lemongrass - Shankar Tucker

Thursday, November 10, 2011

Sexual dimorphism in humans shopping clothes

Well, this topic is definitely so cliche, that i dont think anyone can add any more info to it. But i had my own little realization about its causes, when i recently went as a bulk-discount-filler with a lady. (i.e. "buy 2 get 2 free, but i want only 2 clothes. Will u club with me?"). And this particular behaviour i'm describing is only restricted to the type of shopping where one says "i need more clothes" rather than "lets go shopping". Buying clothes in these two modes is very different, but i guess i wont get into that now. And my observations are based on a rather small sample size of n~=5 females. But, i'm definitely not willing to spend time trying to increase the sample size, for obvious reasons.

Disclaimer: I'm not a sexist pig. Dimorphism doesnt mean one way is better. It just means there is a difference.

The phenotype:
Males choose a shop based on monetary + style + variety based considerations. Go in. Visually pick a bunch of things that they like. Try them, pick a few out of the n options. Done.

Females choose a shop based on similar parameters. Pick a whole lot of things. Try some of them. Buy none. Repeat these steps in another shop. And keep repeating until you have checked all shops in the area. And then either go back to one of the shops (where she might even have picked a fight with the shopkeeper) or a very likely other option - dont buy anything at all. And repeat this in another area some other day.

My hypothesis of the cause:
Females have a particular image in their head, of what they want to buy, before they enter any shop. If they dont find things matching the picture, no matter how awesome it is, they wont buy it. The best that piece of clothing will fetch is a "ah, thats nice and cute. But not now". Well, the rationale is that they wouldnt want to subtract out from the budget for the thing in their mind. But, this of course depends on how much money one has at hand.

Males get into a shop unprejudiced by what they want. In some cases, they even dont have a model of what they already have. Buy almost everything in one shop, even though it might not be the best deal for all of the items purchased, because they are lazy to invest so much time on clothes.

Current mood: meh
Currently listening to: Indifference - Pearl Jam

Friday, October 14, 2011


Found the word that fits what i love to do a lot these days..... Playing with the Arduino and basic electronics stuff, not particularly for any use, but just knowing that u can do stuff..... Or doing roundabout solutions to simple problems, just so that you can get to use some cool thing you have.  Unfortunately, DoodleTronics is some stupid company's name which has nothing to do with tronics, and probably a little to do with doodles. No matter, doodletronics it is!

Current mood: inventive
Currently listening to: Tuesday's gone - Metallica

Wednesday, September 28, 2011

Javadi Hills | 6 Jun 2011

There have been a lot of posts pending, regarding quite a few treks. Here's one more of 'em

Where: Javadi hill region, Eastern Ghats, Tamil Nadu

Who: Srikanth, Vinay and meself

Srikanth was back to Bangalore after a while, and he was itching for a trek. A friend had told us about this nice place called Javadi hills in north Tamil Nadu, where she had earlier gone for some social work stuff. This fit the bill perfectly, as we had only one day at hand.

We boarded a bus to Thiruvannamalai at night. And then waited for a bus to Jamunamarthur (via polur) that would arrive at ~4:30 am..... We waited sleepy eyed for the bus.... None of us knew to read tamil. Except, Vinay recognized some letters, and we would try to auto-complete the words. All of us were experts in speaking broken incomprehensible tamil though. So we somehow got our questions across to people. And we could sorta get most of their replies as well....

There's always a stampede to get into these buses. So we rushed and joined in at the first bus that showed up around that time. We grabbed and blocked our seats, and were proud of our abilities in this field! But, we were on the wrong bus, which we asked and figured out in a short while..... So, we had to do this ritual all over again, until we were on the right bus. Luckily, the next bus we rushed into was the right one.

Around a coupla hours and we were out of the bus. (I forget the name of the place presently. I guess you can ask for melchapli[pronounced male-cha-plea]  and be dropped off at the right spot).... We filled our bottles with water at the village near the road, and asked directions to melchapli. And there was a big fat wide jeep track that led there. We followed the track religiously, assuming that it will turn exciting sometime later, when we could actually do the wandering stuff. We reached Melchapli even before we could complete the thought. And by that time, we drank the water we collected at the village, and it was downright horrible to taste. We saw a dried up stream on the way up, and then realised that we will not get any water anywhere on the trail. We ususally dont carry too much  water, cos there are always streams where you can get refills.... But not this time... It was the core of summer in this region

A little beyond and downhill from melchapli was kilchapli (keeL- cha -plea), where we refilled with some water (which tasted much better. But we only had 2 litres of water for the three of us. We asked the way to the ruins of the dwarf settlements (which is a mild tourist attraction there. And if you fumble long enough to hunt for words to describe ruins and dwarves, they usually figure out what you want and direct you).... And before long, we actually hit our destination: the ruins of the dwarf settlement on Javadi. And we were there by as early as 9:30 am, thoroughly dissapointed at the lack of challenge as well as the lack of nature, as most of the route we walked on established trails from village to village.

After dillydallying around on the top, and staring at the descent down the hill into the village at the base (but opposite side to the way we came), we decided to go down the hard way, carving our own route. It was getting hotter, but there was some respite in the shade of trees and shrubs. We were making good progress initially until we started getting dehydrated.... We added electral in the last litre of water. That got over quicker than the first one

Dehydration hit me first of the three.... i started cramping while doing some tricky sections.... After some time, my steps faltered, and i started slipping quite a bit.... Slowly went into a zombie mode.... Soon, the others started showing effects of mental stress due to dehydration. We started yelling at each other for no reason.... The village was easily visible to us, and we could hear kids shouting there....... It was that close, yet so far (pardon the cliche, but those words are exactly what describe it best)..... Finally, i just gave up and sat down, saying i couldnt take it anymore.... I gave them my gps, and marked the location at which i was gonna stay. And they would go down and get back with water.

I sat there exhausted, muscles sore from all the cramps, and slipped into delusions. Every few minutes i hallucinated that someone was calling my name.... And then, i slipped into a dream maybe where i was sitting at that spot waiting until the next day..... And in some i was in a much more crippled state, and was getting down like the guy in Touching the Void. When i woke up from that, i was so glad that nothing serious had happened..... I just needed water, which would slowly arrive, and all would be fine. The triviality of my situation compared to the one in 127 hours and Touching the Void, brought me instant cheer and inspiration..... With some more time spent with hallucinations and dreams, i heard the real voices of them calling out for me. I gupled down a litre and half of water in one go! (plus electral), waited a while, and then started down the descent through some thorny brush.

Soon we hit the village and gulped down more water. Then it was a long boring road to the bus stop where we had to wait two hours for the bus to come. We hitched a ride on a tractor until some distance. Then it was the bus to thiruvannamalai.

Thiruvannamalai was another big mess! There was some festival or some auspicious day, and devotees crowded the bus stop, waiting to swarm into any bus that gets in. And we were in no strength to fight for seats. We booked a room and went back to Bangalore the next morning.

That day definitely made it to the top 5 of the most exhausting days in my life.

Bus to Thiruvannamalai. Bus to Jamunamarathur from there, via Polur. Ask for Melchapli(mel-cha-plea near Javadi, and the conductor will let you know at the right stop).

Head to Melchapli, then to Kilchapli (KeeL-cha-plea), and then ask for dwarves' houses and ruins). Someone called them 'pyramids' as well!

If you want to go down the steeper face of the hill like we did, carve your own way down. But here's our overall track, in case you need some idea.

The splattering of co-ordinates are either because we roamed around a bit in those regions, or when the gps recception was inaccurate due to interrupting foliage.

Current mood: Dehydrated just thinking about that day
Currently listening to: Given and denied - Poets of the Fall

Wednesday, September 21, 2011

Fooood please

The world record for most number of food items on display in a single day is 5845. And that was a cheese based theme. i.e. they made 5845 cheese dishes (well..... the sponsor was some cheese company!). The total number of dishes in the world must be a hundred fold more maybe? 584500?

Now let's say i've got a hundred years more to live (i hope not though).... And say i eat a new dish every  time i have a meal. I'll eat 3*365*100 = 109500 meals..... And yet i wouldnt have tasted all the food in the world!

And thats why, every time i eat something i've already had before, and am not so fond of, i regret that its taking the place of something exciting and unknown, which i'll never have a chance to even try!

Current mood: vagabond-ish
Currently listening to: My body is a cage - Peter Gabriel