Theo Verelst Diary Page 163

Thu Nov 28 2002, 12:47 PM

I've decided after good example to write some diary pages with toughts and events.

Oh, in case anybody fails to understand, I'd like to remind them that these pages are copyrighted, and that everything found here may not be redistributed in any other way then over this direct link without my prior consent. That includes family, christianity, and other cheats. The simple reason is that it may well be that some people have been ill informed because they've spread illegal 'copies' of my materials even with modifications. Apart from my moral judgement, that is illegal, and will be treated as such by me. Make as many references to these pages as you like, make hardcopies, but only of the whole page, including the html-references, and without changing a iota or tittel...

And if not? I won't hesitate to use legal means to correct wrong that may be done otherwise. And I am serious. I usually am. I'm not sure I could get 'attempt to grave emotional assault' out of it, but infrigement on copyright rules is serious enough. And Jesus called upon us to respect the authorities of state, so christians would of course never do such a thing. Lying, imagine that.

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Sun Nov 24 2002, 2:29 AM

Major changes in my possibilities in a not unimportant area: web access: I'll often have fast enough web access from a machine I can put stuff on, I don't know what will all happen, but I might even be trying a server out.

Thu Nov 28 2002, 12:47 PM

At this moment. as long as a certain machine keeps running and subsequent dhcp certificates are consistent, I have a test html server running (legally, even, realy, it is) at

   http://195.241.128.75

it seems in fact the same address as yesterday evening, after a few restarts, probably that won't happen in weekend rush.

You're welcome to try it out, though it is just a mimimal test at the moment, a few pages, some random pictures, and the server statistics page. For the hackers amoung you, I did disable the 'debug' in-core cgi from the standard server distribution, so no remote scripting on the server should be possible. I'm not sure some kind of logging is on, there's just this nice little tcl/tk window with the number of url requests.

I did do a almost extensive system backup recently.

The thing runs on XP, on a reasonably up to date machine, with me meanwhile watching the dutch énquete committee' on a PC TV card, while typing, running  cygwin/Xfree86/KDE (on top of windows !), trying out javac 1.4 (works, but again networking in applets is interesting point), and yesterday compiling and now testing and disecting the latest gnu/cygwin compiler, which is one of the post powerfull tools around, probably (as the experts know, linux is almost completely built through that piece of software. It compiled itself: vive open source and good internet connections).

Seriously the whole compiler itself compiled through the standard cygnus 'setup'  supplied (www.cygwin.com), in about an hour, and at least some simple programs worked, including some math, after of course pointing to the right paths and library locations, also the self-compiled ones. What a power to get into most of all in modern pc computing, in open source. Wonderfull.

Quantum Physics for layman


And women.

Lets start by analysing a simple, overseeable everyday experiment, as it seems.

The expectation value of repeatedly throwing a dice

Even though Einstein was of the conviction at some point that God doesn't play dice, lets see what we statistically can say about the basic statistics of throwing an ordinary, 'good' dice, meaning one which has equal probabilty of rolling to either of its six sides, and one which is thrown in a perfectly random way.

As most will know, that means that we say that the expectation value of  the dice rolling to either side is 1/6 th for all sides equal. How can we test that idea? Mainly by applying the thesis or law of big numbers, that is we throw many times, an keep track of the results, and tabalize and analize in a way which seems fit.

For instance, we could make a graph or the number of times each side appears in the throwing, and we expect in principle, and normally fine enough in practice, that after a large number of throws, each bar of the six, for each of the six sides, becomes equally high.

Of course we could also flip a coin in an 'honest' way, in which case we would have only two columns in the graph, one for head, one for tails, and they to would be equally high in the long run.

   ^
11|
10|
 9 |
 8 |       *            *
 7 |       *            *
 6 |       *            *
 5 |       *            *
 4 |       *            *
 3 |       *            *
 2 |       *            *
 1 |       *            *
 0 -----+--------+----->
        heads      tails

We know the, as it can be formulated in mathematical sense, expectation values for the probabilty of throwing heads or tail for the case of the number of experiments, in physcal language, approaching infinity.

We know that that means that if we flip a coin a limited number of times, to begin with when we throw a odd number of times, the bars in the frequency graph should be equally high, but aren't necessarily.

We could say that we have a mathematical/physical formulation of the statistically known dice or coin, and that we are interested in a certain quantisation of the infinte, continuous or completely accurate statistical analysism which is an experimental result wth countable, limited probability distribution.

As most digitally interested people may know that if we take a number of possibilities which is based on a two valued experiment is related to the number of 'binary' results (heads or tails, 1 or 0) by the formula pow(2,n), where pow is power, in this case with base 2, and n is the number of experiments or bits. for n=10 that is 1024 pow(2,10)= pow(2,5)xpow(2,5) =(2x2x2x2x2=32)x32 =1024).

Can we with certain and correct mathematical accuracy reason about the outcomes of such experiments? for instance, suppose we filip a coin n times, what is the probablity following straightforward statistics that we end up with an experimental result which in the quanization following from the number of throws presents us with the outcome of n/2 per accumulated result for heads and tails?

Yes, we can, it means we must flip the coin an even number of times, and end up with a string of results where the numbers of heads is equal to the number of tails, lets call them 1 and 0 respectively, which is equal to exactly n/2, where n is the number of experiments.

How many possibilites do we have to put ones and zeros in a row when the total number is n, and of each there are n/2 ?

That, too, is a commonly eniugh known statistical problem, known as a over b or something equivalent, though probably that is for the not so average highschool students. It is defined as a!/(a-b)! as I remember by heart, and can be seen as follows, we start with an empty sheet with a number of dots for each 1 or 0 equal to n. Now we start with placing n/2 1's at the desired position, for which the first has n possibilities, the second n-1, the third n-2, etc until (n-n/2+1)=(n/2+1), which is equal to n faculty divided by n/2 faculty.

To get the probablity for finding exact ffty fifty distributions based on n binary experiments with expectation value for the average of 0.5, we take that number of results and divide it by the total number of possible results, being pow(2,n), 2 to the power of n, the nuber of flips.

How big a numbers are these? For n=1, we know the answer, we can have 00, 01, 10 or 11, so we have P(n1=n/2) = 0.5, meaning the probabilty of finding one 1 and one 0 with two coin flips is 0.5 or one half.

For n=10, we compute that getting 5 heads and 5 tails when we flip 10 times has a probability of

   10/5x9/4x8/3x7/2x6/1  / (2*2*2*2*2 * 2*2*2*2*2)  * 100% =


Rest of the page is in buildup


Fri Dec 27 2002, 05:33:57

I got caught here !

Not realy that much, but the above equation , now I see back the unfinished page has the well known one out of so many with or without ordering idea in it. When I take time, I'll bring it up, update the page, and write more. The problem is important, and I was even quite fluent in the area, and in fact years before I did make it through my official university statistics exams, so I'm more than qualified for it...

The below is from an italian who puts biblical scenes on a well er, nude calender, which was on I think cnn or bbc or the local dutch news, or some of them, it is from rome I think, and of course was controversial, though I'm sure the sixties inheritance doesn't make us or little boys or girls affraid or taken aback by the nudity itself, which at least isn't gross or offending.



Below is a scan of an experimenters board for electronicists as I described a few years ago, in this case with a memory chip on it on the right, and a buffer with dataline LEDS (the little lights with no glowing wire), which is used to either see what is in a certain memory location, or to write a new binary number in a certain place in the memore, which is determined my the wire connections on the right. The 128 Kilo byte memory seems to work fine, and will probably end up in another Z80 computer board in buildup.



I scanned this from a print I have made some time ago, someone I knew, when I saw her and made the picture I still was working in the gallery s*, and didn't spend much time, she seemed dismayed and I didn't quite get the type of interest she showed. Its at a big arts fair in Amsterdam, and I cut out some others.



This is from the publication board at electrical engineering dept. in Delft university, from the mathematics study club...



When do you get things for free in modern life? Well, electronicists are not just from this world, I got my parts some time ago, possibly with some delay, by applying for them on the website of analog devices and texas instruments, and this part is particuilarly interesting as it got sent from the states over ups (or which was it)  and contained one state of the art digital signal processor sample in a socker ball sized box with plastic flakes...