### Archive

Archive for the ‘The Web (Blogs, Forums, etc)’ Category

I got used to all sorts of weird translations provided by Google Translate, but today I found out the strangest so far – it translates my name. OK, I wouldn’t be surprised if it translated my surname literally, as it is a common noun in my native language – but no: it translated my name and surname with a name and surname of another man!

I clicked on the translated name to see other suggestions – and there were two more people as possible translations. Little bit of googling has shown the connection between the four of us – we are all on a same list published on scribd. Still – there are thousands of names on that list – why did he match me with those three people? Furthermore, it translates my name from my native language to all other languages in same manner – but not from other languages.

I tried few other names from that list – people I know – and one also gave this type of translation (although it offered just one translation, compared to three given in case of my name) – but others showed no trace of abnormality. Again, native language -> any other language gives the translation, any other language -> any other language doesn’t.

P.S. Don’t think I’m weird because I google translate my own name – I was translating an abstract of my paper and found out that someone else apparently wrote it, judging by the translation…

## Dear John

January 20, 2011 1 comment

Judd Hirsch - now everyone knows him as Alan Eppes from Numb3rs...

The following post has nothing to do with the “Dear John” TV show, as you might have guessed, seeing that screen shot. I just used the title – this post is inspired with John Baez’s latest post on Petri nets.

Very often I find the things I study as an EE student totally useless. Few weeks ago we had a lecture on Petri nets in the Distributed systems course – and today I read John’s excellent post about it. It reminded me of John’s TWF posts about analogies in various branches of physics (electrical engineers could enjoy it starting with week 289).

Thank you John for showing me that there are ways for a mathematician (I doubt I’m a mathematician, but I am certainly not an engineer either) to enjoy engineering courses.

I had a funny experience with WolframAlpha recently. I typed in:

differentiate (t-t^2/2)Heaviside(t) at t=0

and the result was (as you can probably see in the link):

$\theta(0)\approx\theta(0.)$, alternate form $1$

Surprise, surprise. The function obviously doesn’t have a derivative in that point, but WolframAlpha bravely calculates it. I tested Mathematica 7 with the same question, using both UnitStep and HeavisideTheta for the unit step function. The difference between these two is that HeavisideTheta implemented in Mathematica is undefined at 0, while the UnitStep’s value at 0 is 1.

Heaviside theta case:

In[1]:=  D[HeavisideTheta[t] (t – t^2/2), t]

Out[1]:= (t – t^2/2) DiracDelta[t] + (1 – t) HeavisideTheta[t]

In[2]:= % /. t -> 0

Out[2]:= HeavisideTheta[0]

As noted, HeavisideTheta[0] has no defined value.

Unit step case:

In[1]:= D[UnitStep[t] (t – t^2/2), t]

Out[1]:=(t – t^2/2) (\[Piecewise] {{Indeterminate, t == 0},{0, \!$$\*TagBox[“True”,”PiecewiseDefault”,AutoDelete->False, DeletionWarning->True]$$} }) + (1 – t) UnitStep[t]

In[2]:= %/.t->0

Out[2]:=Indeterminate

This opens few other questions about these calculations, but I’ll stop right here.

## Mental note: avoid small web communities

This might be extremely subjective, but I cannot help it: one of the StackExchange forums annoyed me. I’m a regular at MathOverflow and I got used to the atmosphere there, so I started browsing other “Overflow” and StackExchange forums. One caught my eye, and I decided to stay for a while. What a bad decision. Its community being exactly ten times smaller than the MathOverflow’s, they cocooned in their own world, solving people’s homework and discussing trivial things. I don’t mind that – I posted a nice soft question, quite similar in nature to three or four excellent community wiki soft questions made on MathOverflow (actually, dealing with the exactly the same topic, but ‘translated’ in the language of the science this SE site promotes). First reply was: bad question, vote to close. OK, I can handle that, but stop acting like hypocrites, guys. Closing questions with some value to a community, and leaving homework questions? For God’s sake, is there a strategy behind this policy?

That SE is somewhere in the bottom part of the scale

Now, why is this brilliant XKCD comic here? Because I seem to past the mathematicians’ purity test (and they are way right on that scale), and I can’t satisfy it in a community lower on the scale? Now that’s something I should think about – or maybe not.

P.S. I deleted the question. You may call me an easy quitter, if you want.