terça-feira, outubro 31, 2006

PMP - Expected Earned Value - EEV

Question from Wolfgang :

"A friend recently told me that he found a question in the PMP exam about expected earned value (EEV).
I've never heard this term before.
I've searched on the Internet, but nothing was found about this term.
Please, can someone tell me where I could find references or a definition about this?"

I doubt that this question is counted into your passing grade.
It is probably one of those 20 "test" questions ...

My take is that this is the same EV as the one in PMBoK but used in a
probabilistic model - so it will be the EXPECTED value formula.

Anyone who has more information about this topic, please send me an email. Tnks.

segunda-feira, outubro 30, 2006

Fallacious Reasoning: "The God Delusion" By Richard Dawkins



“Science can chip away at agnosticism, in a way that Huxley bent over backwards to deny for the special of God. I am arguing that, notwithstanding the polite abstinence of Huxley, Gould and many others, the God question is not in principle and forever outside the remit of science. As with the nature of the stars, contra Comte, and as with the likelihood of life in orbit around them, science can make at least probabilistic inroads into the territory of agnosticism.”

In “The God Delusion” by Richard Dawkins

Uhm...How can you do that Dawkins, when your knowledge of Statistics is so frigging fuzzy (I’m using a polite word here)?


NB: This review heavily relies on probabilistic concepts (*I'm looking at you Dawkins*).

I haven't thought about this aspect of the philosophy of math in a while since my college days. I guess I could get behind the idea that frequentism is incompatible with a finite world even though it seems to work well on paper and in the head. There's also the Bayesian view which thinks about this topic differently based upon prior and posterior although I'm not sure Dawkins could salvage any of his probability arguments without question begging. One of my fantasies is to see a frequentist and Bayesian go at it in a stats smackdown/debate.

On with the argument.

I've always found Dawkin's statements strange when it comes to God's existence statistics-wise, and coming from a biologist (I thought these guys would be fairly proficient in the arcane arts of Statistics and Probability). While absence of proof is not necessarily proof of absence, absence of evidence is routinely considered as evidence of absence. Consider this thought experiment: I toss a coin intending to prove that it is a two-headed coin: neither side of it is 'tails'. The coin comes down 'heads'. Have I proved my hypothesis? Obviously not. I toss it again: 'heads' again. Proven? No. I toss it 100 more times, for 100 'heads'. Have I proven my hypothesis? No. In fact there is no number of tosses that can prove the hypothesis - though a single result of 'tails' would instantly disprove it. So the absence of that proof of 'tails' - i.e. a 'tails' result - is indeed not a proof of 'tails' absence ... but the one thing that is certainly true is that the accumulated series of 'heads' results is evidence of 'tails' absence! The more 'heads' results I get, the greater the accumulation of evidence that 'tails' does not exist, given the "a priori" assumption that both sides of the coin are equally likely to appear at each toss. So absence of evidence is evidence of absence ... just not proof. Dawkin's unfamiliarity with the laws of statistics extends to his misunderstanding of statistical issues, which is quite surprising when we consider how important statistic is for any any branch of science, certainly for his area of "expertise", Biology. Dawkins, I want you to state what his your p-value for your hypotheses that God does not exist, ok? Can we have that, please? After you state that, we can have a proper discussion on the "existence" of God.

The above-mentioned thought experiment can indeed be related to the existence of God. Every possible scientific inquiry we make about the universe which, if the universe were created by a supernatural entity, could reveal indisputable evidence of that supernatural entity but fails to do so (having a natural or mundane explanation instead) is like a toss of that coin coming down 'heads'. The evidence accumulates that no 'tails' exists. And those 'coin tosses' - scientific experiments across thousands of years - are in the millions now, and no credible evidence for a supernatural being has been revealed. It's not proof of the non-existence of God, but it's an accumulation of evidence.

Personally, I think spirituality is an internal experience which is hard to classify and something some people feel drawn to. Those who are not drawn to spirituality can seem to be angered by those who are. In the early Christian Gnostic 'Gospel of Mary Magdalena it says 'God can be found in the silence'. Perhaps, if atheists would really like to understand the pull of spirituality they should try meditation. It would certainly make a refreshing change from those who scour the Old Testament to find things to complain about (perhaps if they realised that many Christians long ago stopped taking the OT literally, they might understand the futility of such exercises). It is very clear from reading both the Old Testament and The New Testament that they are written not only by very different people and a different era, but the whole style and approach to God is very different. In the OT God is rather wrathful, extremely powerful and sometimes unforgiving. Whereas Jesus spent his whole time stressing love, forgiveness and kindness. His kindness was often commented on and often shocked people used to less kindness from their orthodox priests of the time. I think the reason that Christianity flourished is because of this new vision of a gentle and loving God. It was revolutionary and people are still struggling to love one another today. The Old Testament, on the other hand belongs to the tradition in which it was written - pre-history by numerous anonymous writers over hundreds of years. But people are usually Christians because of the new kinder message of Jesus Christ (hence the name) and not because of the OT.

Bottom-line: Dawkins has become better known, these days, as an anti-theistic polemicist (or is he a warrior of truthfulness?) than as a scientist or an intellectual. He's not out to enlighten, elucidate, or engage in the serious discourse beliefs as serious and strongly held as his deserve; rather, he seems content merely to mist all who fail to avoid him with bafflingly smug proclamations from atop the impossibly high horse upon which he is evidently stranded. He's become a rabid dogmatist as insufferable as any other dogmatist, extremist, or fundamentalist you're likely to meet, and he can't keep his mouth, or fingers, shut. By no means does my little diatribe imply that the religionists should have the stage while atheists and anti-theists must remain silent. (For ex: Which am I, anyway?) I do maintain, however, that if this man expects to be taken seriously any longer, he is well advised to procure a strong crowbar to pry his intellect open a tad (or at least learn Statistics), as well as at least enough humility to respect not only others beliefs, but others for their beliefs. He's an arrogant twat. People who accept his point of view behave as he. People who find it difficult to square his "mathematical opinions" with their beliefs (or knowledge) to the contrary (regardless of your opinion on the last two nouns) feel threatened by his rabble rousing belligerence. People who believe they are threatened generally behave as if they are threatened. What's so interesting or not self-evident about that? Dawkin's bias comes from the old platonist vs formalist split. Dawkins may see physics quantum fluctuations as perfectly real existing entities, though no one has seen any such thing directly but God is, at best a name a notion. Hey Dawkins, Quantum Physics is just a man-made representation of reality. It's not reality! Why does Quantum entanglement works? No one knows! This is all assumption. I am not a fan of organized religion and condemn as Dawkins does the terrible cruelty inflicted upon humanity by organized religion over the centuries. I am also no dogmatist. What I care about his Science. And this is why I think Dawkins is just after you for your Euros. He does not have the intellectual wherewithal nor the initiative to present cogent arguments to counter theists directly; he simply takes the stance that anything that is not conventional science is illegitimate. That is dogma and such laziness.

NB: In this review I’m not proving or disproving God’s “existence”. I’m just debunking Dawkin’s “science”.

terça-feira, outubro 10, 2006

Die neue Prüfung des Goethe-Instituts ( Das Goethe-Zertifikat B2 )

Der Gemeinsame Europäische Referenzrahmen für Sprachen (GER) definiert verschiedene Kursniveaus vom elementaren bis zum kompeteten Sprecher.

Prüfungen macht man sein ganzes Leben lang. Erst in der Schule, dann an der Universität oder in der Berufsausbildung. Geht es um konkrete Fachkenntnisse, scheint das Abfragen von Kenntnissen und Fertigkeiten leichter zu sein als bei der Frage: Wie gut beherrsche ich eine Fremdsprache? Beziehungsweise wie sind meine Kenntnisse im Deutschen im Vergleich zu anderen Sprachen? Dank dem Gemeinsamen Europäischen Referenzrahmen für Sprachen (GER) haben alle Sprachinstitute und Testautoren Kriterien an die Hand bekommen, die es ihnen erlauben, die Kompetenzen auf verschiedenen Niveaus zu bescheinigen.

Die "elementaren Sprecher" (A-Niveau) zum Beispiel können sich in einfachen, routinemaBigen Situationen verstandigen, in denen es um einen direkten Austausch von Informationen über vertraute und gelaufige Dinge geht. Die "selbständigen Sprecher" (B-Niveau) können sich 50 spontan und fliessend verständigen, dass ein normales Gesprach mit Muttersprachlern ohne grössere Anstrengung auf beiden Seiten gut möglich ist. Die "kompetenten Sprecher" (C-Niveau) können sich spontan, sehr flüssig und genau ausdrücken und auch bei komplexeren Sachverhalten feinere Bedeutungsnuancen deutlich machen.

Welche Prüfungen des Goethe-Instituts welchen GER-Stufen zugeordnet werden, können Sie in der unten stehenden Tabelle ablesen ( von der Cambridge School ). Wie aus der Übersicht erkennbar ist, fehlte auf Niveau B2 noch eine Prüfung. Dieses Goethe-Zertifikat B2 - so der neue Name - ist nun fertig und wird gerade erprobt, das heisst, es wird an verschiedenen Goethe-Instituten im In- und Ausland durchgeführt und korrigiert, die Ergebnisse werden miteinander verglichen, die Aufgabenstellungen überprüft, alies wird statistisch ausgewertet, dann werden notwendige Korrekturen vorgenommen. Das Goethe-Zertifikat B2 soll 2007 offiziell eingeführt werden.

Gleichzeitig hat man die Zentrale Mittelstufenprüfung (ZMP) überarbeitet, um eine sichere Positionierung auf C1-Niveau zu gewahrleisten.

Daher muss ich die ZMP-Prüfung im Februar 2007 ( oder am spätesten im Juni 2007 ) machen. Diese Prüfung wird sich ändern ... Ich habe schon angefangen, mich auf diese Zertifizierung vorzubereiten. Darum muss ich auch auf die neuen Versionen der Prüfungen des Goethe-Instituts nicht warten !

Viel Spass beim Üben!

Trust the Science: "The End of Nature" by Bill McKibben



(original review, 2006)

"Climate is a Chaotic System
Chaotic Systems cannot be predicted
Climate, therefore, cannot be predicted.
The IPCC has stated this explicitly."

I've been hearing this almost since forever. But is it right?

Predicting a Chaotic System is BY DEFINITION impossible. Climate is a Chaotic System. Ensembles are used to try to mitigate the nature of a Chaotic System by extending how far out one might be able to present probabilities for different scenarios. This is done with weather forecasts all the time. They use ensembles which is why they present the possibility of rain next Thursday as a probability. But as you know, these are often wrong. So if they are right, there is an element of luck involved as the conditions that will (or will not), cause it to rain in five days are changing by the minute. The calculation of climate variables (that is long term averages) is much easier than weather forecasting, since weather is ruled by vagaries of stochastic fluctuations, while climate is not. We can demonstrate this sort of climate response clearly in the Lorenz model, or any more complex climate model. Perturbing the initial conditions gives a completely different trajectory (weather), but this averages out over time, and the statistics of different long-term runs are indistinguishable. However a steady perturbation to the system can generate a significant change to the long-term statistics. This disproves the common but misguided claim that chaotic weather prevents meaningful climate prediction. In fact, all climate models do predict that the change in globally-averaged steady state temperature, at least, is almost exactly proportional to the change in the net radioactive forcing, indicating a near-linear response of the climate, at least on the broadest scales.

At the centre of chaos theory is the fascinating idea that order and chaos are not always diametrically opposed. Chaotic systems are an intimate mix of the two. From the outside they display unpredictable and chaotic behaviour, but expose the inner workings and you discover a perfectly deterministic set of equations working like clockwork. Some systems flip this premise around, with orderly effects emerging out of turbulent and chaotic causes. With respect to temperature the climate system is such a system.

I'm not part of this book’s intended readership as I don't need convincing and I can cope with (quite a few of) the technicalities. However, I am extremely glad that it was written, as it is fundamentally important to seek as wide an audience as possible with regard to this issue.

What’s the difference between a denier and a sceptic? These two things are not the same - scepticism in the face of something relatively new is perfectly reasonable, indeed it is 'scientific' to be sceptical, at least to begin with. However, this is a rapidly moving field of knowledge. “Denialism, on the other hand, especially in the face of the steadily accumulating body of evidence, is both stupid and very probably dangerous. As I said elsewhere, we are taking steps on a road which could lead, in the end, to a 200 metre rise in worldwide sea levels, albeit not for quite a long time in human terms. Politicians and economists plan for this year and next year - maybe the next five or ten if you're lucky. They don't plan for the next hundred or five hundred. And that is part of the problem - getting people to understand the long term* risks, given that we are talking about a process which, in human terms, is gradual and so for most of us, most of the time, tomorrow will look much like today.

I apologise if i sound a bit snippy as I'm not meaning to. Some moderately technical books which I could recommend to our Deniers are John Harte's Consider a Spherical Cow and the follow-up Consider a Cylindrical Cow. Neither goes beyond elementary calculus, though I realise that statement would not be very comforting to a lot of people:) The first volume specialises in what I would call 'back-of-the-envelope calculations, and covers a lot of basic climate science. Then there is Princeton University Press's excellent Primers in Climate series, of which Climate And The Oceans is typical. Again, they contain maths up to elementary differential equations, but this is a field where you really can't do much without some of it I'm afraid.

(*) The economist John Maynard Keynes, who has a strong interest in physics, once famously remarked: 'In the long run, we're all dead.'

I agree with the fact that it would indeed be nice to live in an intellectual world without a cultural divide, but I suspect that it has no likelihood of happening any time soon. I became more sanguine about this attitude only when I read books by people who are clearly cleverer than me who apparently felt much the same, plus I learned a whole host of techniques for obtaining approximate analytical solutions to various difficult equations, and the less difficult ones i can solve exactly anyway. One of the books in question is The Pleasures of Counting by T. W. Korner, who has these three things to say about computing, when it is necessary (in the real world I'm well aware that it very often is):

1) Does the program start? Many fail to do this.

2) Does the program stop? See point 1)

And by far and away my favourite:

3) Can my valet use it?

Presumably he is not being entirely serious, but it makes me feel better anyway:)

On the point about two cultures, it is hard to improve on the late, great Terry Pratchett's observation, via the medium of one of his greatest characters, the (arts-educated) Lord Vetinari in the Discworld book The Last Hero:

He hesitated. Lord Vetinari was not a man who delighted in the technical. There were two cultures as far as he was concerned. One was the real one, the other was occupied by people who liked machinery and ate pizza at unreasonable hours.

Thank you for that, that makes me feel somewhat better:)

I suppose that I'm almost the reverse of a lot of people in a way - I was a precocious child. You can probably see why Pratchett is very much my cup of tea though (he has been compared to Charles Dickens, though obviously with a lot more laughs).

At 13, however, I discovered an interest in astronomy, and, after reading various non-technical (no equations) books on the subject, I found a technical one on stellar structure in a bookshop. Of course, I had no idea what a differential equation was at that point, but I knew i needed to find out, so I developed a parallel interest in mathematics, which, along with physics/ astrophysics, has sustained (and delighted) me ever since. I can definitely say that that book really made an impact on my mind.

Back in the day, I did private tuition in both subjects (**), which means that, with the bright ones, as well as making sure they knew the syllabus, I showed them some of the more interesting (***) stuff - usually in response to questions that they have asked in school and been fobbed off with 'you don't need to know that for the exam.' For me, there is almost no greater pleasure in the world than to be a teacher in the company of an interested and intelligent student asking questions.

(**) However, when you consider that even my A Level physics students don't know who Maxwell was (i make sure that they find out!), then, sadly, i wish that i could be modestly surprised. Which i'm not. To be fair to them, it is true that they don't really know anything about Newton and Einstein either, other than their names, but our society's total ignorance of the man who gave us the electrical modern world is rather depressing. On that basis therefore you really haven't got a (Schrodinger's?) cat in hell's chance of them knowing about Dirac.

(***) I realise that the definition of this word varies with the individual.


Climate change will be addressed when money can be made out of doing so - probably. It appears to be too late to stop the changes that are unfolding due to the delay between polluting the planet and the resulting climatic changes that will be a big problem for civilisation. I have formed the view that are now in a position where emissions reduction on its own will be inadequate to prevent changes. We will need to actively remove CO2 from the atmosphere to a level of about 260-300ppm (my estimate based on general reading of reliable reports).

So who is going to pay?
The taxpayer as always. You and me and generations to follow of course.
And the scumbags who happily did this to us, and their spawn, will get even richer.
And the poor will suffer - more.
The politicians will look earnest. The financiers will continue to gamble the world's wealth. The dog-botherers will continue to disrupt debate. The do-gooders will continue to wring their hands and dole out charity.
The scientists will continue to research, publish papers and just get on with giving us answers.

One bright thought; if dealing with climate change was more profitable than selling armaments there might even be some ancillary benefits. I am cautiously hopeful we can science our way out of this. Civilisation is now so science dependent that there really is no alternative. If civilisation breaks down badly, there are about 100 nuclear plants worldwide that would probably melt down and become world changing catastrophic disasters. There are millions of tons of lethal chemicals and pollutants in storage at any time that require constant and careful management. If all that get loose in the environment it could change life on Earth forever.

It is too late to give up. We broke it, we have to fix it. That means science and lots of it. Catastrophe capitalism will kick in - probably.

Bottom-line: In J. E. Littlewood's A Mathematicians Miscellany, which is a delightful mixture of gossip, academic bitchiness and some actual mathematics, he attempts to estimate the probability of a celluloid mouse's prospects of survival in what he refers to as The Institution. It is not very high. Unlike his great friend and close colleague, G. H. Hardy, Littlewood saw saw no reason to apologise for being a mathematician. Believe in the science and forget the politicians. You have to understand the processes of denial. Those who have blinded themselves to the slow moving changes in the climate and repeat phrases to reassure themselves that nothing is happening are unwilling to even consider any events that do not conform to the narrow views of their ideology. That ideology confuses freedom with personal choices. As if the right to drink a certain brand of cola or drive a gas guzzler were rights guaranteed by the US Constitution. They take climate change as a personal encroachment on their rights and look for someone else to blame. The smartest deniers are able to come up with rationalizations to hide behind. Trust the science.

EDIT 2018: I should update this review, but why? What was true in 2006 is still true today.

segunda-feira, outubro 09, 2006

Die Verlotterung der ( deutschen ) Sprache, d.h., die deutsche Sprache auf SMS-Niveau!

Save the German Language ( and the portuguese too, come to that )! They're a shambles !



That is :"O abandalhamento da língua ( alemã )" in portuguese, "The Running to the Dogs of the ( German ) Language" in English.

For those of you who have an interest on this subject, I would recommend reading the main article published in the Magazin Der Spigel ( 02.Oct Edition ) : "Rettet dem Deutsch !". Very instructive ... ;)

The roots of some German words date back centuries, making each a tiny "cultural monument." If more Germans were aware of this, they might take greater care to preserve and promote them. German nouns, often have shorter English equivalents making the English an attractive linguistic short cut. But I mantain that what these words gain in "easiness", they lose in accuracy or clarity. The strength of German is its "concreteness", the result of many logically constructed compound nouns. Moreover, English words ripped from context and plugged without sense into German — Handy for cell phone, for example — take on new, often distorted meanings.

If I get sufficient requests I may post the entire article here ... ;)

PMP - Function Point Analysis

Question :

"Taking some practice test in preparing for the exam and the correct answer for a question on cost estimating was "Function Point Analysis". I could not find any reference to it in the PMBOK or various study guides I have. Searched the internet, and it appears this is a tool used mainly in SW development. I know I have seen recent postings that say you should be ready for anything on the exam but is this really that common of a tool that most PM's should know?
Is this a good example of what might be on the exam? Thanks in
advance."

I know ... There're lots of concepts that show up on the PMP-Exam literally out of the blue. This is one of them. You must expect this type pf things to happen. It's quite common to see concepts creeping up into the exam... It's enough to knock you out of your stride ! Beware !

"Function Point Analysis" is used to estimate the size of Software projects.

PMI focuses Project Management (in all disciplines) not just on Software Project management.

For the PMP exam all one needs to know is that "Function Point Analysis" is one of the methods used for estimating the size of Software projects.

There is no common tool for estimating all projects.

However, there are common principles in estimating that PM's can use to estimate the cost of the project like top-down, bottom-up,etc. These are already mentioned in the PMPBoK.