Google+

You might find my Google+ stream more entertaining these days: https://plus.google.com/u/0/112590156611730454107/posts

RTS AI - Lingering Ideas

A while back (ok, fine, almost a year back) I talked about a RTS AI Competition held in the sidelines of AIIDE.

The results (with videos) are listed here, and there is a presentation on the competition which provides an overview of the participants and results. There is an arstechnica article of the winner of the full game called Overmind.

Video describing the Overmind AI system (but more on what it does than how the smarts work)

The presentation describes the Overmind bot as using "a variety of AI techniques for decisions at various levels of abstraction", which tells me nothing. :)

My own inclination, if I had the time and the support to do so, would be to implement an RTS using Monte-Carlo Tree Search. I have the ingredients and the framework laid out in my mind, just that it seems like it is going to remain just an idea as I work on "real-world" problems (hey, it pays the bills).

p.s.,  For those interested in research in this area, scanning the accepted AIIDE 2011 papers reveals this paper, "A Bayesian Model for Plan Recognition in RTS Games applied to StarCraft".

See you on the other side

I admit it - I am spending way too much time on Google+.

I need to figure out how to partition my musings; here's my best stab so far:

• Links - Google+
• Short witty comment - Google+
• Embarassing photos of children - Google+ (with my "real" friends!)
• Long (>140 characters) comment (regardless of wittiness) - Blog

I guess that relegates Twitter to rants. Bye Facebook!

Amazon Reviews might not all be truthful

You might be interested in How Aunt Ammy Gets Her Free Lunch.

In the first academic study of its kind, we examine the elite class of top-thousand Amazon reviewers by conducting a detailed survey with a subset of 166 of these top reviewers. The study, examines everything from age, gender and education (typically middle-aged, male and master’s degree), to the motives and concerns of this volunteer corps who’ve helped drive Amazon’s growth from quaint virtual bookstore to the planet’s most valuable retail brand. 

Wisdom of the crowd corrupted by greed. I am sure nothing can go wrong. :)

Keepalive

I am currently busy with greedily packing sleep in my constrained satisfaction problem of handling both an increasingly talkative toddler and a mountain of work.

Basically...
SYN
SYN/ACK
ACK

For those who know TCP.

Seriously, you have most likely been tying your shoes incorrectly.

What it is like inside Apple

Fascinating article by Adam Lashinsky on How Apple Works. 

"Can anyone tell me what MobileMe is supposed to do?" Having received a satisfactory answer, he continued, "So why the fuck doesn't it do that?"

For the next half-hour Jobs berated the group. "You've tarnished Apple's reputation," he told them. "You should hate each other for having let each other down." The public humiliation particularly infuriated Jobs. Walt Mossberg, the influential Wall Street Journal gadget columnist, had panned MobileMe. "Mossberg, our friend, is no longer writing good things about us," Jobs said. On the spot, Jobs named a new executive to run the group.

The full article text can either be gotten from the Fortune app in iTunes, or as a Kindle single for $0.99.

I didn't even notice

My parents came over from Singapore to help with the new baby, and today my mother wanted to call a friend in Singapore and asked to use my phone (a Nexus One). She was pretty impressed that the calling rate to Singapore was $0.02/min using the Google voice integration (check here for more rates).

Nice. Calling home has changed, and I didn't even notice. I must have blinked. :)

Update on Monday, April 18, 2011 at 6:56PM by Yew Jin

Please, no wise cracks about me not being mentioning Facetime and iPad 2.

Firing Squad

A lunch buddy shared an interview question that he had heard from another tech company. It is a thinly veiled CS question, which sort of threw me off my tracks, and made me slightly embarassed it took me a few minutes to get it.

N (where N > 1) prisoners are being lined up to be shot by a firing squad. Each prisoner is given a helmet that is colored either red or green. The prisoners are lined up facing one direction - so the last prisoner can see the helmets of every other prisoner except his own, the second last prisoner can see everyone's helmet except for his and the last prisoner's helmet.

In a strange twist, the crazzzzy chief prison warden decides the firing squard will spare the life of any prisoner if he or she can correctly name the color of his helmet. The firing squad will start from the last prisoner and move sequentially to the first prisoner.

Before the firing squad begins, all the prisoners are placed in a holding cell and they make use of the opportunity to discuss a strategy to maximize the number of prisoners saved.

What is that strategy?

Update on Sunday, April 17, 2011 at 8:21AM by Yew Jin

The best strategy guarantees to save the (N - 1) prisoners except for the last prisoner, with 50% (?) chance of saving the last prisoner. We codify the colors of the hat into a binary system, say 1 for red and 0 for green. The last prisoner will report the parity bit of the prisoner helmets in front of him. This means that the color of his own helmet is not a factor in what he reports. Under simplifying assumptions (the color of helmets are truly random), the chances of the last prisoner not being shot is 50%.

The other prisoners now can use the parity bit reported and deduce what the color of their own helmet is.

Pardon my tardiness

To anybody who has been emailing or contacting me to no reply, I apologize but I have been busy - mainly because my second baby is due in less than a month! I will try to get back to those emails when things have slowed down. (I guess that means in 18 years? I kid.)