Category Archives: Miscellaneous

(American) break

We are flying, this morning for three weeks in the National Parks, in the western part of the United states. First stop, Las Vegas, as mentioned in a couple of posts already. I did mention in a post in April that I did plan to visit the casinos, but more to see people gambling. And in that post, I noticed that if you play the roulette, and if your plan is to double your gain, then you’d better play big. And bet everything once. Actually, it did happen a few years ago, as a friend recently told me. Ashley Revell, 32 by that time, literally sold every that he had owned to bet on the roulette table (in Vegas). The total of his possessions came to £76,840, which gave him around $135,300 in total to bet with on one spin of the roulette wheel. And he did play everything. Ashley pushed his chips on red, the ball bobbled around the wheel, and it finally came to rest in the 7 Red slot, doubling his winnings to $270,600. But actually, as Ashley explained, it was surprisingly difficult to find a Casino in Vegas to take up such a large bet (most of them simply refused to host to such a big gamble). But a TV show decided to record the bet, and the high stakes bet was finally taken up by the casino at Plaza Hotel.

But I do not plan to play everything I own. And I really want to enjoy that break, so the blog will be probably be off for a few days, I might upload some pictures, because places we’ll visit look simply amazing, but I should be back to work in a bit less than three weeks.

(updates of the trip will be on the kids blog, for those who know it).

Quiet “holidays”?

People outside academia often wonder what we might be doing when we do not teach. And actually, my teaching session ended on May (I do include time to grade). So am I on holiday?

I have to admit that starting last Tuesday, everything looks more like holidays, since the kids started their own. Even if I have to prepare lunch boxes, it is not the rush to go to work. And they like to go to bed late (or at least later), we did enjoy the Jazz festival this weekend, this week it will be the Circus festival and we plan to see the fireworks contest, and when we’re not downtown, we also enjoy going to play basketball at the playground next door. So yes,it might sound like holidays…

But even I feel more relaxed, I do work. And to be honest, I feel extremely busy. Which might explain why the blog was so quiet those past days (actually, since the kids are – also – busy, I do spend time to upload pictures and videos on their own blog… more time on their, less time on mine).

At the beginning of this month, we were working with Ewen on the paper (now submited) and the poster (he did won the poster contest at the R conference in Lyon, congrats Ewen) on smoothing densities on maps. I am also trying to finish another couple of papers I would like to submit (at least to post on http://arxiv.org/) before going on holidays. I am also working with colleagues from the SoA (I was in Chicago mid-June, since UQAM is a center of excellence, and I will be in Atlanta mid-July to work on the new general insurance track), and also working with (and for) students. Trying to send emails to make sure we’ll get our datasets in September, for instance. I have also admistrative duties, like making sure that colleagues I should be working with in August will find a place to stay when they will arrive in Montréal. I also have to plan skype meetings with co-authors, to see where we are on our projects, before having a break, planning what should be done when we’ll be back, mid-August, etc.

But what keeps me really really busy is the book I am editing. I spend time reading contributions, trying to unify notations and concepts, making sure that references are correct and relevent, etc. I am in the flat part of the productivity curve. Time when spending 1 full day on a chapter will generate 5 new pages is over. On 1 full day, I can simply fix a few typos, change a graph, find a nice reference. It is long. And painful. But in two weeks, we should have a preliminary version, that we will all cross-read, including colleagues who told me they were interested to have a look at it. In two weeks, I will be off! And I really need that break!

Eat a beaver, save a tree

Wednesday, just before leaving the office, I remembered I wanted to buy Andreas Kyprianou’s book, on Lévy processes. A second edition is coming soon, but I just need a simple introduction to Lévy processes, so I thought that this first edition should be complicated enough for me. And when a second edition should appear soon, you can get a discounted version of the (almost) old one. So I went on Springer’s wesite to purchase the book. I did pay for the book, and finished packing, in order to go back home. I did receive my confirmation order, which is standard, and I opened it,

Wait! “eBook“, “Download PDF“? What does that mean, I thought I was buying a book, like those we can hold in our hands…  Indeed, on Springer’s wesite the default version seems to be that eBook, and you have to look, in the back, to get a Softcopy, which should mean a hardcopy with a softcover. I have to admit I started to freak out. I never buy eBook! I am extremely old fashion! Those who know me know that I even print pages from the internet to read them! Anyway, I sent emails to all possible contacts I could found on Springer’s wesite, trying to get in touch with someone who can cancel my purchase. I mean, I did not download to PDF, so, from a technical point of view, each customer does have a dedicated link, and they should know I did not download it! So, until I download the PDF by clicking on the link, somehow, I do not have it, right? So I did ask them to delete the link, refund me, and then I will get back on their website to purchase the book (after two days of discussion by emails, they keep telling me I did buy a book, so I have to admit that I do not know which word I should use to describe that antique object made of paper). Actually, when I said that I made a mistake, that I just wanted to return the product I did not consume (I do not know how to return a link actually), that I wanted at the first place to get a paper copy of the book, I got that legendary answer,

Dear Arthur Charpentier,

Thank you for your email and interest in our products.

This is to inform you that it is irrelevant for us to proceed with your request, because it has already been entered into our database/system.

However, when you have downloaded the PDF copy of the E-book. You can print manually through your printer.

If you want a paper copy of a book, “you can print manually through your printer.” At first, I thought it was some kind of misunderstanding. Or joke, maybe. But no. You cannot cancel a purchase when you order eBooks. And to make sure that I got the book, they did send me the full pdf in my mail box. What I am supposed to do with that file? This is not what I wanted! I wanted a book! a book with paper you can hold in your hands! with paper, made from trees that died so that I can learn stuff!

Anyway, I gave up… I will ask colleagues if I can borrow their copies. Now, I have to fight with Dell since I ordered a laptop (yes, the Ubuntu version), and it did arrive at the office in a wet box. Looks like the computer (at least the box) has been staying in the water for a very long time! I don’t know if people around still believe that researchers actually do research when they have time… trust me, they don’t! They discuss with Customer Services… and it can take a while!

In three months, I’ll be in Vegas (trying to win against the house)

In fact, I’m going there with my family and some friends, including two probabilists (I mean professionals, I am merely an amateur), with this incredible challenge: will I be able to convince  probabilists to go to play at the Casino?

Actually, I also want to study them carefully, to understand how we should play optimally. For example, I hope I can make them play the roulette. Roulette is simple. With a French (or European) roulette, it is probably the simplest: if I bet on black, I win if one of 18 black numbers is out, and I lose if one of the 18 red numbers – or zero (which is green) – is out. This gives a winning probability of 18/37 i.e. a 48.64% chance. But in Vegas, I think it’s mostly American Roulette that can be found in casinos, in which there is a zero and a double zero (both favorable to the bank). Here, the  probability of winning is 18/38, i.e. 47.36% chance. The two roulettes are

Now, let us discuss a little bit about optimal strategy. For instance, suppose I go to Las Vegas with an initial wealth  (say $100). The goal is to find the strategy which maximizes the probability to leave Las Vegas with https://latex.codecogs.com/gif.latex%20?2s (here $200). Should I play big, or small ?

Assume that I can bet https://latex.codecogs.com/gif.latex%20?x (that will be, here, for convenience, a fraction of ). With probability https://latex.codecogs.com/gif.latex%20?p, I will get https://latex.codecogs.com/gif.latex%20?2x, and with probability https://latex.codecogs.com/gif.latex%20?1-p, I will get https://latex.codecogs.com/gif.latex%20?0 (and lose my https://latex.codecogs.com/gif.latex%20?x). As mentioned above, https://latex.codecogs.com/gif.latex%20?p is (a little) smaller than 50%. The casino must win (actually, we will see that this assumption has a very strong impact on the strategy).

Suppose my goal is to double my initial sum, as mentioned in the introduction of this post. Maybe there is an optimum value for https://latex.codecogs.com/gif.latex%20?x, to maximize the probability of doubling my bet. To make it simple, the game ends either because I did not, or because I did, manage to double my initial wealth… Assume further that https://latex.codecogs.com/gif.latex%20?x is fixed, and that I do not revise my bets. One can use monte carlo simulations, to get an intuitive idea…

> bet=function(s=1,t=2*s,x=s/4,p=.4736,nsim=100000){
+     vp=rep(0,nsim); #vw=s
+     for(i in 1:nsim){
+       w=s;
+       while((w>0)&(w<t)){
+          ux=sample(c(min(x,t-w),-x),size=1,prob=c(p,1-p))
+          w=w+ux
+       }
+       vp[i]=(w>=t)}
+     return(mean(vp))
+ }

If we plot this probability as a function of , we have the following

> BET=function(x) bet(x=x)
> vx=1/(1:20)
> px= Vectorize(BET)(vx)
> plot(vx,px,log="x")

Let us see if we can do the maths, and actually compute those probabilities.

For example, if https://latex.codecogs.com/gif.latex%20?x%20=%20s, I play everything I have, and I double with probability https://latex.codecogs.com/gif.latex%20?p. That one was simple.  And indeed, on the graph above, the point on the right is probability  https://latex.codecogs.com/gif.latex%20?p (the red horizontal line).

Assume now that I can bet https://latex.codecogs.com/gif.latex%20?x%20=%20s%20/%202, and I will play, at least, two rounds

  • with probability  I will lose both rounds (and the game is over)
  • with probability , I will win both rounds, and I double my bet (and the game is also over)
  • with probability , I will lose once, and double once. Anyway, I will find myself again with my (initial) wealth . So the game will start again….

To make the story short the probability of doubling my earnings is

which is

https://latex.codecogs.com/gif.latex%20?p%20^%202%20\left%20(1%20+2%20p%20(1-p)%20+%20[2p%20(1-p)]%20^%202%20+%20\cdots%20\right)%20=%20\frac%20{p%20^%202}%20{1-2p%20(1-p)}

Let’s try something more general: I have initial wealth , I can bet https://latex.codecogs.com/gif.latex%20?x and the goal is to reach  (or, more generally, say, ). Now, the probability to reach  from  betting (always) https://latex.codecogs.com/gif.latex%20?x is exactly the same as the probability to reach  from  betting only 1. Let  denote the probability to go from  to  betting 1 (let us use generic parameters). We can easily get the following equation

https://latex.codecogs.com/gif.latex%20?P_b(a)%20=%20p\cdot%20P_b(a+1)%20+%20(1-p)%20\cdot%20P_b(a-1)

Thus, we can write

https://latex.codecogs.com/gif.latex%20?p\cdot%20(P_b(a+1)-P_b(a))%20=%20(1-p)\cdot%20(P_b(a)-P_b(a-1))

or equivalently

https://latex.codecogs.com/gif.latex%20?(P_b(a+1)-P_b(a))%20=\frac{1-p}{p}\cdot%20(P_b(a)-P_b(a-1))

https://latex.codecogs.com/gif.latex%20?\left(\frac{1-p}{p}\right)^a\cdot%20(P_b(1)-P_b(0))

Now, observe that https://latex.codecogs.com/gif.latex%20?P_b(0)=0 (since I cannot have a gain without any money).

Let us write https://latex.codecogs.com/gif.latex%20?P_b(a+1)-P_b(0) using a domino technique :

https://latex.codecogs.com/gif.latex%20?[P_b(a+1)-P_b(a)]+[P_b(a)-P_b(a-1)]+\cdots+[P_b(1)-P_b(0)]

i.e.

https://latex.codecogs.com/gif.latex%20?\left(\frac{1-p}{p}\right)^a%20P_b(1)+\left(\frac{1-p}{p}\right)^{a-1}%20P_b(1)+\cdots+%20\left(\frac{1-p}{p}\right)^0%20P_b(1)

so this geometric sum can also be written

https://latex.codecogs.com/gif.latex%20?\left(1%20-\left[\frac{1-p}{p}\right]^{a+1}%20\right)%20\left(1%20-\left[\frac{1-p}{p}\right]%20\right)^{-1}

Finally, we can write

https://latex.codecogs.com/gif.latex%20?P_b(a)=\left(1%20-\left[\frac{1-p}{p}\right]^{a}%20\right)\left(1%20-\left[\frac{1-p}{p}\right]%20\right)^{-1}\cdot%20P_b(1)

Here, there is still  that I have to explicit. The idea is to observe that , thus

https://latex.codecogs.com/gif.latex%20?P_b(a)=\left(1%20-\left[\frac{1-p}{p}\right]^{a}%20\right)\left(1%20-\left[\frac{1-p}{p}\right]^{b}%20\right)^{-1}

So finally,

https://latex.codecogs.com/gif.latex%20?\mathbb{P}(gain)=\left(1%20-\left[\frac{1-p}{p}\right]^{s/x}%20\right)\left(1%20-\left[\frac{1-p}{p}\right]^{2s/x}%20\right)^{-1}

Nice isn’t it? But to be honest, there is nothing new here. This is actually an old theorem discovered by Christiaan Huygens in 1657, then extended by Jacob Bernoulli in 1680 and finally properly established by Abraham de Moivre in 1711. It is possible to plot this graph, as a function of ,

> bet2=function(s=1,t=2*s,x=s/4,p=.4736){
+     vp=(1-((1-p)/p)^(s/x))/(1-((1-p)/p)^(t/x))
+     return(vp)
+ }

The graph is the same as the one with monte carlo simulation (hopefully). Observe, looking carefully at the function above, that the probability is decreasing with . Which makes sense… Further, the probability is decreasing with : the more hungry, the less chance of winning I have.

Now, the interesting part is what is plotted on the graphs above: the smaller  (the size of the bets at each round), the less chances to win: if I want to win, it is important not to play being little player ! I must bet everything I have ! Actually, the funny thing is that if the probability of winning was (slightly) larger than 1/2, on the contrary, I should bet as small as possible

So far, there is nothing new. Everything mentioned in this post can be related to a fundamental result of Lester Dubins and Leonard Savage, in “How to Gamble if You Must : Inequalities for Stochastic Processes” (published in 1965), see also Sudderth (1972). Of course, I can try another strategy, a little less reasonable, I think, which is sometimes called Martingale of D’Alembert. I believe more in luck than coincidence, so, when I win, I drop my bet (do not tempt fate) but when I lose, I increase my bet (I must win someday). But let’s keep it for another post, someday…

Again, that’s a theory. I guess we should try, and see how it works. I’ll try to upload pictures on the blog during the road trip, so if by the beginning in August nothing has been posted on the blog, please send a rescue team to save me at the Bellagio…

Diary of an addict

After four days offline (at least off my blog, see the previous post for more details), I have to face the truth: I am a computer addict. For sure. Here is the diary of the last four days, that were supposed to be without touching my computer, at work and at home. I tried to keep tracks of everytime I had to go on my computer. At home, that was fine (I have decided a few weeks ago that I should not check my email at home, in the evening, and in the morning, so unless I want to read the news, check on Twitter what’s going on, or write a post on my blog, I do not usually spend much time on our computer). But at the office, that’s another story…

  • Tuesday, April 2nd

6:17 Wake up, first day of the challenge.

8:17 Time to check if the code used for datascraping (on some websites) did run… It’s not like using my computer. It was just fixing problems for a future research. One minute, just cheking. Well, there was a problem in my code, I have to fix it (it takes much longer than I thought) and then, I ran it again (in order to exact some figures out of almost 200,000 internet pages). One code has been scaping a website for almost a week (and it looks like I have only one third of the data), and the other one, I have to run it everyday, to backup some daily figures from several websites.

8:32 While going to get a coffee, JF shows me the web site of the Antartica Journal of Mathematics (where he was kindly invited to submit an article, and also to apply if he’s willing to join the board) and we go through Rob Hyndman’s warning on his blog, about junk journals. No offense to the webdesigner hired by this journal, but we had a lot of fun on that website… so… nineties.

8:47 I have to go online, on my email account to download a paper I have to review. I had a reminder by an editor this weekend. Print the article. While seeking for the email, I notice that I did receive during the night an invitation to give my opinion about another article, for another journal. Just go briefly through the paper. Even if my (personal) quota for 2013 is already exceeded, I decided to accept to write a referee report. Also check something with a co-author. Quickly. Also read four comments on the blog submited during the night, and approve all of them. Damned! one of them mentioned a preprint related so something discussed in a post. Try to avoid to read the preprint. Go offline. Definitively. Turn on the music. Sacred music, namely In Seculum Longum.

9:39 After alsmost 30 minutes reading articles, I give up. I open LaTeX to type corrections for a couple of chapters I have to write down (and send them as soon as possible, the deadline was last week). So far, no internet. I take a gum, I feel nervous…

9:44 Go online to check how to use enquote{} in latex (it looks like I have some damned babel problems !) Go on several forums. Spent the morning working on my LaTeX files.

12:54 Back from lunch, I turn off the sacred music, swith to Sandinista, by The Clash,

13:14 JF want to check with me the schedule for my graduate courses for Winter 2014 session, one on extreme values and copulas, and one on time series. Have to go on the website of the university, to find what has been planed. Spend also some time seeking for old emails, since the information is only partially online.

14:02 Have to go online, one more time, to buy a ticket for the French railway, for a colleague of mine.

14:17 Mathieu asks me go check the emails received this morning, and to send an email in order to confirm that I will join a meeting about the organisation of a workshop.

14:40 Discussion with Mathieu about resubmiting an article. We need to go on my email account to check several (interesting) comments from the referees.

15:03 This time, I have to launch the internet browser. I have to find out how to avoid fist names in a bibliography, using a bib file, and get only initials. Some more time on LaTeX forums.

15:08 Remember that I have to book a room for a colleague, visiting me this August. Need to check the price on the webiste, and send emails.

15:19 Wrote a recommendation for a former student of mine. Send it.

15:26 Discussion by email with two co-authors, since we did plan to work on a joint paper this month.

15:48 Time to work on slides for a conference at the end of this month, and write codes to produce some graphs. So, still on my computer. But not (really) online.

Finally, I went back home early, to cook, and spend some time with the kids.

  • Wednesday, April 3rd

Second day.

8:17 Check again my R code. Run again one of them. Looks like there was a problem.

8:50 Go to give my course. Until noon, I spent the morning producing codes, to show how to compute chain ladder estimates, and explain roots of bootstrap in regression models.

13:03 Buzy red light on my phone when I get back to my office: it looks like some people at the faculty tried to reach me. Usually I do not answer the phone. I hate my phone: you want to reach me, send me an email. OK, in my mailbox, there are a couple of emails from the faculty “please, call us back, regarding the conference you plan to organize”. Damned, how can I tell them I am on a mission, that I try to avoid using my email (and that I have to deal with my phone-phobia at the same time).

13:16 Go online to check code for an R package I want to use to produce nice graphs

13:30 Check quickly my emails, delete 90% of them, answer to one, postpone others. Decide to go to work in a coffee shop, the whole afternoon. While taking the elevator, I started to discuss with a colleague. Looks like I missed an email about a meeting that will take place in the afternoon. I want to work on my chapters. I go to the coffee shop. Nothing serious in the meeting, as far as I understood. I spent the afternoon reading, checking typos in chapters that should be sent soon, and articles on advanced methodes in finance, based on trees… No computer for a few hours ! I did it !

17:49 I have to go online at home, time to pay my HydroQuébec bill. Damned !

17:56 While I am about to log off, I received an email from a former student of mine, with a link to a nice article (entitled “l’informatique, ça s’apprend“) I really want to share it. But I can’t. Less than 36 hours after my mission, that would be a defeat ! Do not go on Twitter !

18:02 Cooking for the kids. Will miss the Montreal Hackathon organized by R users. Wednesdy evening is not a great day to join those social events (could geek meetings be called social ?). My wife has a late course in the evening, and I still try to see how deeply addicted I can be. I finally decided that I will check my emails twice a day. But just to remove spams (or messages like “I am a student in a engineering program from India and I would like to start a PhD with you“, or “the back door in one of the building will be locked during the week-end from 22:15 till 23:42 for security reasons“) and to see if there might be important ones. Probably have to answer some of them, but I’ll try to postpone for most of them.

18:41 started a game of kid audio with the girls. Almost became a pugilat when they started to argue about kettledrum and snare-drum, I wanted to show them on youtube, but finally I gave up (there is an old saying: never interfere in a girl-and-girl fight). Decided to ask the elder to read a story to the youngest, while I was washing the dishes (which is usually the perfect timing for a dvd). Meanwhile, it looks like my son went online, for his music assignment: his teacher is using online videos to help them practicing. Argggg.

  • Thursday, April 4th

Third day.

8:29 As usual, checking the code for datascraping… reload the one that did crash (again) during the night

Error in substr(html, 8, 12) :
  invalid multibyte input string at '<e9>lair,'

Damned. Moving around 200,000 pages without being caught is difficult. Have to play some music. Gonzales, piano solo.

8:47 Have to check quickly my emails. The problem is that, on average, per week day, I have a bit more than 100 emails (excluding official spam). If I do now scan them, I end up with on thousand emails very quickly… Need to moderate a comment on the blog.

8:50 Still online, checking my emails, bad news about fundings for a student of mine, have to send a couple of emails to find a backup solution.

8:54 Quick discussion by email about copyrights for a chapter in a book

8:54 Have to send also emails to book a room for a colleague who will visit me in August

8:55 Postpone a Skype discussion with a co-author, still trying to avoid unecessary use of my computer.

8:57 Answer an email to schudele a meeting because a student asked to get a grade revision, and an adhoc committee is necessary. Looks like I am part of it.

9:17 Start to write recommendation letters for a Christophe who’s applying for positions in several universities, in France.

9:34 Back on the slides and the R code. On my computer, but offline.

10:11 Email, brief answer to a former student of mine, who might be interesting to share some datasets, but it looks like there might some confidentiality issues. I wanted to work on those data with a student, in September. Have to find an alternative.

10:45 Discussion with student in master program (face to face this time). Have to go on Dropbox to download a pdf file he wrote, and to download a couple of paper to check the proofs.

13:05 Work with Amadou, my phd student, need to find a pdf version of a book, since the property is clearly given there, but the book is out of print (no way to get a paper copy). Also go online to find a reference on a complicated model.

14:40 Email from Fred, about a reserving technique that seems new, from a paper he just discovered.

15:03 Upload on slideshare some (old) slides that do the same thing that this new paper (aren’t there anyone checking before publishing papers that results are really new ?)

15:14 Play Rodrigo y Gabriela, need something punchy to finish my day

16:56 Received an email from the immigration department, and I have to go to their website to find a doctor for a medical examination of the whole family.

19:26 Request by email from financial services to get the exact amount (in Euros) taken from my credit card. Have to go on my bank account, online.

19:43 Disccussion by email with Frédéric about one year uncertainty and bootstrap with overdispersed Poisson models

  • Friday, April 5th

Last day of the test. Fourth day.

06:18 My daughter wakes up and tells me it is unfair to have snow for her birthday. Have to go on http://meteomedia.com/weather/… to check for weather forecasts. Hopefully, we should have nice weather this afternoon…

08:16 Once again, checking R codes, still running this time ! Great ! Time to play some music.  Air, Premiers Symptômes.

8:38 Email regarding next week jury, checking legal aspects

9:04 I have to print bank informations, that I did download yesterday, check orders placed on Amazon in the last 3 months, scan documents, send them to financial services.

9:13 Have to check for an account number with financial services

9:15 Brief email to some contributors of a book that I should edit this year.

9:21 Lauch Skype, have to discuss with coauthors in France.

11:54 Received an email about courses in September, looks like a quick answer is needed.

13:10 Update the syllabus for the course I will give in September. Decided to write that cellphone will not be allowed during the class.

14:12 Work with Ben, a master student, on a paper. Need to scan notes I have written down to send him by email (this time, we did work together without using my computer).

14:38 Finished my recommendation letters for Christophe (for positions in France, more than a dozen recommendations). Have to send them individualy by email. Have also to find some email adresses that I do not have.

14:49 Received an email claiming that I cannot give my (graduate) course on extreme value in 2014, not in the official programm. Have to spend some time checking why. It seems that it has been removed from the list, and that the code has changed (hopefully JF was online to check that information much more efficiently than I would).

14:59 Received an answer from one of the colleagues I just sent recommendation to. We used to be students at the same time, a few years ago. Write a short email back to give (personal) news.

16:19 Started to type sketches of what can be the final exam for my course on GLM for actuarial science. So far 5 questions. Need to find about 40…. Will take a while.

Mission aborted.

I finally left the office later on, to pick up my son and bring him to his fencing course (to prepare for the Jeux de Montréal that will take place tomorrow). Went back home, then, for a cake with candles for my daughter’s birthday. Later on, had to spend some time online, on the blog, for my students. And started to type this post. So, here was the story of the past four days. I have to admit that looking back at those four days is quite informative :

  1. I cannot work without a computer, I can hardly work offline. No only for my research, to get help from forums on R and LaTeX, or to seek articles (the time I spent in Paris at the library making photocopies of old articles is clearly over).
  2. I do not only need a computer to write R codes, and produce LaTeX slides and artices. I need a computer… for everything. To plan meetings, for social interactions with colleagues, to find some help, to find a theorem, to book an hotel, etc.
  3. I understand more clearly why I am so unproductive in terms of research ! it looks like I spend (I was about to say waste) a lot of time on administrative tasks. Small tasks. But adding a lot of small tasks, finally, it is difficult to have 4 or 5 consecutive hours to work exclusively on some research project.

Off for a couple of days

This morning, the elder kids start at school a program called ten days with screens off. Since we do not have a TV, they were wondering what would it change for them. Because they start to spend some time on our computer at home, they’re not supposed to use it for the next ten days. And to be consistent, I have decided to follow their tracks. The problem is that I do not think I can survive at work working offline for ten days. But I want to try. At least, no more computer for the next two days (except Wednesday morning since I have my class). If possible three. No emails (can we survive in the academic world without an internet connection for two days?), and no more posts on the blog (and activities related to the comments) for the next days…  I’ll be back in … a few days (if I do not – finally – find my blogging activity useless and meaningless).

“I am sorry to inform you…”

I just received another decision letter for a paper submitted.But this time, it was fast. In less than 24 hours, I received a notification by email (the name of the journal is hidden with xxxxx’s for obvious reasons):

Dear Professor Charpentier,

Thank you for submitting your paper to xxxxx.

In order to provide a quick reply to your submission, an automatic process, has been used according. The process is based on proximity measures between the article you submitted, and recent articles published in our journal.

1) The correlation between your keys words and standard keywords in xxxxx is rather high (0.926).

2) 66% of your keywords do match with the top 10 most cited papers in 2012 in xxxxx, so your paper has 90% chance of getting at least 4 citations in less than a year and at least 17 citations in less than 5 years.

3) The rate of references cited in your article that were published in xxxxx is high enough (37%) to consider a publication in xxxxx

The academic and citation based score is 0.857 which makes the paper suitable for publication. Nevertheless, before publishing the paper, major revisions are necessary,

1) Your style does not fit well with our journal: your sentenses have (on average) 13.3 words, while the standard in this journal is 16.2. We recommend that you use longer sentences or delete some periods in your text.

2) The words you use are not close enough to the scope of the journal: for example, estimator appears only twice  (the average is 4.34) and methodology appears only once (average 3.67).

3) The affiliation is not appropriate: this year, 12% of the articles received were from authors in Canada. In order to reinforce positive discrimination, it would be better if your affiliation were from the Eastern Europe (currently only 4% of the articles we receive are from Eastern Europe). We can provide you with a list of potential universities if necessary.

4) Your name is not valid for xxxxx:

  • For a single authored paper, the most common first letter in the last name of the first author is H not C and your name which contains 11 letters is too long (the average is 7.91 letters). Lastly, more than 62% authors have a middle name, we suggest that you add one,
  • For a paper with two authors, the most common first letter of the first author is D, hence C is fine, but your name is a bit too long since the average number of letters in the last name for the first author is 9.57.

Thus, we recommend either that you change your name (we can provide you with a list if necessary) or that you find another author to add on your paper and delete the last two letters of your last name.

For the reasons listed above, we have to ask for major revisions. When the paper is resubmitted, it will be send to a (human) referee for proofread,

Please note that we receive almost 1,000 submissions a year; our target acceptance rate is 10% and many good papers get rejected.

Thank you for giving us the opportunity to consider your work.

Sincerely,

(etc)

Damned ! That was close ! Let me find a co-author to add, and I resubmit it !

Le libre, et l’universitaire

On a pu lire ces derniers jours plusieurs articles sur le libre accès aux publications scientifique. Je pense à la tribune “qui a peur de l’open access publiée sur http://lemonde.fr/sciences/… . Etant hébergé par http://hypotheses.org/ qui milite en faveur du libre accès, et d’une plus vaste diffusion des travaux et de la culture scientifique, je n’y suis pas insensible. Sur les publications, la conférence des présidents d’université a aussi publié un document intéressant, intitulé “bien universel, par essence, l’article scientifique, n’est pas un bien comme les autres” en ligne sur http://cpu.fr/

En fait, le but de mon billet aujourd’hui était non pas de discuter sur le libre accès aux publications scientifiques, mais à revenir sur l’utilisation des logiciels libres dans le monde universitaire, et plus spécifiquement sur la place du logiciel libre dans l’enseignement.

En lisant Scott Wilson, qui a publié “open source in higher education: how far have we come?”,  sur http://guardian.co.uk/higher-education-network/… je l’ai trouvé un peu trop optimiste. Dans son article  il note que “universities are ahead of the curve in adopting open source, we should now lead the public sector in exploring its full potential“. Jusqu’à aujourd’hui (ou disons récemment pour être honnête), j’étais assez étranger au débat. Certes, j’utilise des logiciels libres, mais juste parce que je les trouve meilleurs. Ce n’était pas du militantisme, juste du pragmatisme. Et depuis quelque temps, je prends conscience que j’ai (ou que nous avons, en tant qu’universitaires) une responsabilité collective. Par exemple dans mes enseignements, j’utilise R (autant le nommer, ce n’est un secret pour personne que la moitié des billets sur mon blog contiennent du R). Mais quand j’étais étudiant, j’ai appris à manipuler des logiciels de statistiques payant (appelons les S pour utiliser une notation générique qui devrait m’éviter des procès pour diffamation). J’ai aussi utilisé S lorsque j’ai travaillé en tant qu’actuaire, car c’était installé sur nos machines, et parce que j’avais appris ce logiciel. Sans parler de premières amours, disons qu’on garde une forme d’attachement, ou de sécurité, à travailler avec les logiciels que l’on a vus (voire appris) durant nos études. On a peur de changer de logiciel, on aime la stabilité
(car admettons le, on est tous aussi nuls les uns que les autres avec l’informatique). C’est un peu ce que l’on peut lire dans un article paru il y a quelques jours dans http://ledevoir.com/politique/quebec/… où l’on apprend que “Québec adopte un autre décret pour la mise à jour de 76 000 postes de la fonction publique, sans appel d’offres, par des logiciels vendus par […]. La facture totale est de 30 millions, pour les licences seulement. Cette mesure d’exception vise à « assurer la sécurité de nos postes »” (c’est moi qui met en gras). Ce n’est pas de sécurité informatique face à du piratage dont on parle ici, mais de sécurité du personnel qui utilise lesdits logiciels (le confort en quelque sorte). On comprends ainsi que S (et je mets dans le même panier tous les logiciels commerciaux, ou presque) offre des licences gratuites aux étudiants. On retrouve là la logique des fabricants de cigarettes il y a quelques décennies (suis-je optimiste ?) lorsqu’ils essayaient d’attirer les adolescents vers leurs cigarettes, tenant compte ainsi de l’addiction qui se crée ?

Comme je le disais au début de mon paragraphe précédent c’est par pragmatisme que, pour ma recherche, je me suis tourné vers les logiciels libres. Mais pour mon enseignement, je n’avais jamais vraiment réfléchi de manière profonde (parce que je ne fais pas de cours d’informatique: si on utilise un langage c’est parce que l’outil informatique est indispensable pour faire de la modélisation). Par simplicité (ou par fainéantise), j’enseignais des langages que je connaissais. J’utilise R dans mes cours, mais parmi mes proches voisins de bureau, Jean-Philippe utilise S (pour faire des régressions avancées en assurance non-vie) et Mathieu utilise un tableur (que l’on pourrait appeler T, pour…. faire comprendre qu’un tableur suffit pour faire de l’actuariat ? que l’actuariat est plus proche de la comptabilité que de la modélisation statistique ?). Récemment, plusieurs petites phrases m’ont poussé à m’interroger. Je pense que ça a commencé quand un(e) étudiant(e) a écrit dans l’évaluation du cours de modèle de prévision que je donnais voilà quelque temps, que mon cours se résumait à”faire de la saisi de données dans un programme gratuit sur internet” (je passe le fait que dans les questions posées aux étudiants qui remplissent l’évaluation, il est demandé ce que les étudiants pensent des présentations faites avec le logiciel P, comme si faire des présentation en LaTeX n’était pas admissible). Il y a eu ce commentaire l’autre jour sur mon blog, où quelqu’un me demandait le code en S pour refaire ce que je faisais en R. Il y a eu ce questionnement l’autre jour : “est-ce gênant si les étudiants du baccalauréat en actuariat sortent de la formation sans connaître S ?” (que j’avais entendu à Rennes 1 lors des discussions du contenu des cours du Master de statistique et d’économie “il est bon que nos étudiants aient 20 heures de cours à S, ça leur permet de mieux se placer sur le marché du travail“).

Le modèle économique est assez incroyable quand on y pense : avec des fonds publics, l’université offre un service avant-vente à des entreprises qui vendent des logiciels commerciaux. Alors qu’il existe du libre qui fait mieux. Et qui continuera à faire mieux si la communauté d’utilisateurs est active. Je pense que les logiciels commerciaux n’ont pas leur place dans les formations universitaires, et qu’il serait temps que les universitaires prennent leur part de responsabilité dans ce qui s’est mis en place Je ne souhaite pas que les universitaires prennent leur part du profit même si ça serait la moindre des choses (il suffit de survoler la page comparison of statistical packages sur wikipedia pour apprendre que rendre accro un étudiant à un logiciel qu’il utilisera pendant 10 ans, c’est assurer entre 10,000 $ et 60,000 $ de licence (pour un utilisateur), sans parler des formations, des livres, etc). Je pense qu’il y va de notre responsabilité en tant qu’universitaire de promouvoir le logiciel libre. Cela permet déjà de comprendre ce qu’on utilise (je faisais un billet la semaine passée, suite à des soucis rencontrés sur le tableur – commercial – T), mais en plus, comme le notait Scott Wilson, “open source not only promotes creativity but helps make technology more democratic allowing a community to work together to solve common problems.” Et je pense qu’il a raison. Maintenant, je suis nul pour faire des tribunes, et je voulais juste que mes collègues prennent conscience de certains aspects d’un débat qui ne fera que gonfler dans les mois qui viennent…

Chercher, et bloguer

Je vais tenter de poursuivre la discussion amorcée dans un précédant billet, intitulé enseigner, et bloguer. Car je suis à la fois enseignant et chercheur. Et comme tous les universitaires, je suis tiraillé entre ces deux activités

(comme je m’en suis expliqué à plusieurs reprises, j’en suis ravi, cela crée une espèce de balance, cf. /1240 par exemple, il y a quelques mois). Mais à ces deux activités s’ajoute l’activité de blogger. Ou peut-être pas, en fait. Car c’est peut-être là l’erreur de raisonnement (qui fait qu’à plusieurs reprises – depuis plusieurs années – on me demande comment j’ai le temps de tout faire): autant enseigner et chercher sont – je pense – deux activités relativement disjointes (j’enseigne finalement assez peu mes thèmes de recherche), autant – comme j’essayais de le montrer dans mon précédant billet – bloguer s’insère dans ces deux activités.

Par exemple, l’autre jour, j’avais besoin d’un test de comparaison de quantiles (sur plusieurs échantillons), alors que je travaillais sur un papier de recherche. Malheureusement, ce n’est pas un problème standard (la plupart des textbook de statistique n’évoquent pas le sujet). J’ai ouvert mon cahier, et j’ai pris des notes, de choses trouvées dans divers papiers (le principal ayant été publié cette année…). Puis quand j’ai commencé à coder (c’était un peu le but), j’ai fermé mon cahier, et j’ai commencé à écrire un billet sur le blog (qui sera bientôt en ligne, sur /4199). Une raison un peu personnelle est que cela me permet de garder une trace de ce code, et de clarifier un peu ce que j’ai pu glaner et lire (j’ai des milliers de fichiers de codes sur mon ordinateur, et j’avoue m’y perdre un peu). Une autre raison est que, quitte à passer une journée, autant rentabiliser ma “journée recherche” (oui, je réserve certaines de mes journées à la recherche, en me coupant un peu des activités administratives, et de la préparation de mes cours) un produisant du contenu publié (sous une forme moins conventionnelle et reconnue qu’une publication, mais en l’occurrence, mon gribouillage ne méritait pas un article académique). Rentabiliser n’est peut-être pas le mot correct toutefois. Mais il présente l’avantage de traduire le fait que mon employeur (et divers organismes subventionnaires) me payent pour produire de la recherche Ce qui signifie que je dois certes chercher, mais aussi transmettre, à un moment ou à un autre. Je n’apporte peut-être pas quelque chose de très novateur (au sens où je me suis contenté d’aller chercher des articles théoriques qui se penchaient sur un problème semblable, je l’ai codé, et j’ai tenté de l”illustrer). Mais… c’est un peu le processus de l’activité de recherche ça, non ?

En fait, à mes yeux, la grande différence entre ce que je publie sur mon blog et ce que je publie (ou que je tente – souvent désespérément – de faire publier) dans des revues académiques, c’est que j’estime que ce que je publie ici n’a pas la prétention d’une publication académique. Au sens où je ne perdrais pas de temps à essayer de faire croire que je vais révolutionner le monde (comme on doit tous essayer de le faire dans un article académique). Pour exprimer le fond de ma pensée, je ne me battrais pas pour qu’un billet de blog soit cité dans une revue académique. Si quelqu’un utilise mes codes dans un article de recherche, je trouve légitime d’avoir un citation (sinon je pense qu’on peut parler de plagiat) mais je ne me battrais pas sur ce terrain car je pense le combat vain. Soyons lucide: si j’ai vraiment l’impression qu’un billet mérite plus, j’en ferais une version que je mettrais en ligne sur arxiv.org.  Cela dit,  dit, arxiv est à peine mieux qu’un blog: on ne peut – malheureusement – pas de contenter de publier en ligne sur arxiv . Souvenez-vous (ça vous est arrivé forcément un jour ou l’autre): comme tout le monde, vous lisez un article sur arxiv  (ou sur n’importe quel site de dépot de preprints, comme hal ou ssrn) et vous le citez, dans un article que vous soumettez. Si l’article est accepté, lors de la relecture, on vous demande “et cet article il n’a pas été publié depuis ?“. Et comme tout le monde, vous mettez à jour la référence, en citant la version publiée. Sans vraiment le lire (à la rigueur, on vérifie que le théorème 2.4 porte toujours le même nom… si on est plus courageux, que les hypothèses mentionnées n’ont pas changé depuis). Oui, sur ce point, le monde des l’édition est d’une hypocrisie infinie. Dans un monde idéal, les blog et les preprints seraient cités, mais on ne vit pas dans le monde des Bisounours (ou Calinours comme on dit à l’ouest de l’océan Atlantique, c’était la minute culturelle du billet)…

Mais je m’égare. La différence fondamentale est qu’un billet n’est qu’une ébauche d’article. Je m’autorise à mettre en ligne des morceaux de réflexions non abouties, sans véritable conclusion. Bref, mon blog est un carnet. Un carnet de recherche, et d’enseignement (c’est probablement pour cela que j’ai été ravi de le publier sur la plateforme hypotheses.org qui propose de publier des carnets de recherche, avec en plus un conseil scientifique). Je renvois aux (nombreux) billets de Mélodie Faury qui a beaucoup écrit – sur son blog infusoir.hypotheses.org sur l’utilité des carnets de recherche, à plusieurs billets de  parus sur reflexivites.hypotheses.org ou de  sur penseedudiscours.hypotheses.org, ou à l’incroyable blog blog.homo-numericus.net tenu par Marin Dacos et Pierre Mounier.

Tous ceux qui m’ont côtoyé ces dernières années le savent: je remplis des carnets. Des carnets à la fois de recherche, et d’enseignement.

https://f-origin.hypotheses.org/wp-content/blogs.dir/253/files/2013/03/Capture-d%E2%80%99e%CC%81cran-2013-03-08-a%CC%80-09.52.30-1024x647.png

(au risque de tuer un mythe, un chercheur 2.0 ça peut être ça: pas de téléphone cellulaire et un cahier pour faire des dessins)

Mais ces cahiers ne permettent de garder des traces que de réflexions, de lectures, de théorèmes, de notes prises pendant des exposés, mais pas de codes informatiques, peu d’algorithmes. Bref, le blog m’apporte un complément important à mes cahiers papiers. L’autre principale différence est que le blog est public, et mes cahiers (relativement) privés. Et le monde de la recherche ayant sa part de secrets et de mystères, j’avoue ne pas publier exactement c de billets exactement sur mes thèmes de recherche. Dans le billet sur les quantiles mentionné auparavant, je prends une illustration sur des séries de température, mais le papier de recherche (sur lequel je travaillais lorsque les questions sont apparus) porte sur un tout autre sujet. Oui, compte tenu de l’esprit de concurrence qui existe dans le milieu de la recherche, il convient de garder une part de secret. Mais on peut rester confidentiel sur ses activités de recherche tout en communiquant…

L’autre intérêt d’un blog est qu’il va plus loin qu’un carnet: si je recopie un article dans mon cahier, c’est une activité de recherche. Si je le recopie sur mon blog, c’est du plagiat. En fait, le blog oblige à restituer avec ses propres mots des choses lues ici ou là. Car il serait temps de l’avouer: si on blogue en tant qu’enseignant, on blogue pour ses élèves; alors que si on blogue en tant que chercheur, on blogue avant tout pour soi. Quand Djalil publie un billet intitulé Euclidean kernel random matrices in high dimension sur son (superbe) blog djalil.chafai.net, il ne blogue pour 100,000 lecteur. Enfin, je pense. Et lorsque je blogue sur des sujets pointus, je blogue pour moi. Pour me forcer à assimiler des notions, et à les réécrire. J’ai presque envie de dire que les lecteurs, je m’en fous: s’il y a des gens intéressés par mes billets, c’est tant mieux, mais si personne ne lit mes billets “de recherche”, ça ne changera pas grand chose…

Maintenant, pour revenir sur la confidentialité, si elle est de mise tant que le papier n’est pas fini, il convient de noter qu’une fois le papier fini, c’est le contraire: il faut le faire savoir, haut et fort. Et là aussi, je dois avouer que le blog a de grandes vertus. Il donne une exposition incroyable,et permet de faire connaître ses travaux. Par exemple, en 6 semaines, 710 ont lu l’article sur la température à Montréal sur  mon blog /2909. Sans compter ceux qui ont lu la version reprise par les agrégateurs, comme r-bloggers.com/… ou architects.dzone.com/… (plus de 1300 personnes l’ont vu sur ce dernier) ou via un flux RSS. Mais en plus des billets sur mon blog, j’ai l’impression que mes articles académiques sont aussi beaucoup consultés (dans un moindre mesure, bien sûr !). Je suis toujours surpris par mon h-index, qui me semble plus élevés que beaucoup de chercheurs biens meilleurs que moi. Et je pense que le blog aide. Je pense que des papiers sont cités par beaucoup de monde parce qu’ils apparaissent tôt dans les recherches sur Google, mes blogs ayant tous été très bien référencés. Une étude (http://arxiv.org/0212043 mentionnée sur http://washingtonmonthly.com/…) disait que les articles cités étaient souvent peu lus, et effectivement, pour être cité, il suffit d’être bien référencé. Aussi, alors que j’ai longtemps cru que tenir un blog actif était contre-productif pour mes activités de recherche (et effectivement, le temps passé à écrire dans le blog se fait parfois au détriment d’autres taches) j’en suis de moins en moins convaincu. Je pense que des papiers ont été cités parce qu’ils sont mentionnés sur le blog. Soit parce j’y mets les textes en ligne (même si je n’en avais pas vraiment le droit), soit parce qu’ils étaient – juste – bien référencés, soit – en étant moins cynique – parce que pour certains papiers, je mets de codes en ligne pour mettre en œuvre les techniques proposées (je pense au papier sur le lissage spatial, /2416, ou tous les billets qui ont entouré celui sur la modélisation de la canicule d’août 2003, tag/heatwave).

Je me suis aussi rendu compte que j’ai gagné du temps dans des papiers car j’aboutissais sur des concepts connexes que j’avais pu aborder sur mon blog (souvent pour m’amuser). Par exemple, dans nos travaux sur les tremblements de terres avec Mathieu, on manipule des shapefiles (/tag/binar). Et je suis très content d’avoir joué un temps sur mon blog sur des problèmes de pistolets à eaux, qui m’ont permis de manipuler certaines fonctions sur les polygones, cf /tag/water. Enfin, plusieurs invitations à des séminaires de rechercher ou des conférences académiques ont été faites parce que le blog donne une relative notoriété, et visibilité.

Histoire de conclure en faisant une boucle, mon billet sur l’enseignement (et l’activité de blogger) venait d’une demande spécifique de Robin. Or Robin avait fait parti d’un projet génial, à savoir le blog statisfaction.wordpress.com lancé il y a quelques années par des doctorants (et post-doctorants) en statistique, sur Paris. L’idée était géniale car elle leur donnait une visibilité incroyable dans la communauté scientifique, avec des informations sur les séminaires, les cours, et leurs activités de recherche. Il n’est pas étonnant de voir autant de blogs scientifiques tenus pas des doctorants – ou lancés alors qu’ils étaient doctorants – je pense par exemple à Corey à Montréal, bayesianbiologist.com ou a plusieurs blogs d’économie, comme le défunt (ou disons resté très longtemps inactif) ecopublix.eu ou mafeco.fr, par Emmeline et  Jean-Edouard, ou encore rationalitelimitee.wordpress.fr lancé par Cyril quand il était encore doctorant. Les doctorants étant les principaux producteurs de recherche, il est logique de les voir apparaître aussi clairement dans la communauté des bloggers tenant des blogs de recherche (pour ne pas dire des carnets de recherche).

Mais bon, il serait temps de clôturer la séries des billets bloguer, c’est génial (surtout que je me rend compte que mon billet part un peu dans tous les sens, et n’a pas la profondeur d’analyse que l’ont peut retrouver dans les blogs d’ hypotheses.org mentionnés auparavant) La prochaine fois, promis, un billet sur bloguer, c’est nul !

Words are important (when dealing with statistics). But still.

In statistics, it might be difficult to know what a symbol stands for. For instance, https://latex.codecogs.com/gif.latex?\widehat{\theta} can either be a real value, i.e. the value taken by a statistics from a given sample. But it can also be a random variable, assuming that the sample is now a collection of i.i.d. random variables. We can usually distinguish https://latex.codecogs.com/gif.latex?x_i‘s (values from a given sample) and https://latex.codecogs.com/gif.latex?X_i‘s (the underlying random variables, i.e. https://latex.codecogs.com/gif.latex?x_i=X_i(\omega) for some https://latex.codecogs.com/gif.latex?\omega\in\Omega). But notations might confusing, and it is hard to distinguish random variables, and values taken by random variables (or realizations). But usually, if we look at the context, one can figure out what symbols stand for.

But sometimes, it is difficult to get a proper definition, not for some symbols, but for words. And most of the time common words. Recently, I wrote a short paper, claiming that it was difficult to model the number of bodily injuries related to car accident, since it is difficult to define death. Actually, the definition of dead did change a few years ago (as weird as it might sound), which did cause a rupture of some series.

I recently had a similar story, discussing with a pharmacist in Montréal who said to me “you French are known to be the world’s champion in terms of drug consumption“, see e.g.

  • The French are Europe’s champion medicine-takers” in http://economist.com/…, mentioning “heavy drug-consumption culture
  • The data show that drug consumption in France remains one of the largest in Europe” in http://bizcovering.com/…
  • France has one of the largest drug markets in the world and the drug consumption per capitahttp://ispor.org/… (among so many articles)

I do not think I am a drug addict (I might be – like most of my colleagues – a coffee addict, but as Paul Erdős  – or more probably Alfréd Rényi – said once, “a mathematician is a device for turning coffee into theorems“). The main problem here is the notion of “consumption“. The economics interpretation is simply that someone buys a product or a service (see http://dictionary.reference.com/…). There is also the food-related interpretation, where consuming means ingesting, i.e. eating or drinking (see http://dictionary.cambridge.org/…).

So pill and drug “consumption” is ambiguous: is it the number of pills purchased, or ingested (actually consumed), or prescribed? The first thing one should remember is that the Social Security in France refunds (almost) all medications prescribed by a doctor. So it is uncommon to leave the office of a doctor without a prescription, at least of aspirin: a visit to the doctor is usually, in France, the opportunity to stock some over-the-counter drugs. The second thing is that there is a major difference between France and North America when we go to the pharmacy. In Montréal for instance, if I have a prescription for 12 pills, then the pharmacist does give me exactly 12 pills (from a big pot). In France, pills are sold in prepackaged boxes, so if the box contains 10 pills, I will get 2 boxes, just to be sure I’ll get my 12 pills. From a medical point of view, I will consume my 12 pills, but from an economic perspective, I will consume 20. So comparing statistics is extremely difficult, not because the the maths, but because it is difficult to define (even simple) concepts.

Inglés ? Französisch ?

When I started to blog, I found it “natural” to blog in French. Not “natural” in the way Dominique Bouhours sees it: according to Bouhours, only the French language exactly reflects the natural way of thinking

La langue française est peut-être la seule qui suive exactement l’ordre naturel, et qui exprime les pensées en la manière qu’elles naissent dans l’esprit

as he wrote it). “Natural” in the sense that French is my mother language. And perhaps also because, as a French, I did not really see the interest of using another language… Yes, somehow, I still feel that we (French people) believe that Antoine de Rivarol was right when he said, in his Discours sur l’universalité de la langue française that French is innately superior to other languages: French has an element of probity attached to its genius, it is not the language of the French, it is the language of humanity

Dégagée de tous les protocoles que la bassesse invente pour la vanité et le pouvoir, elle en est plus faite pour la conversation, lien des hommes et charme de tous les âges, et puisqu’il faut le dire, elle est de toutes les langues la seule qui ait une probité attachée à son génie. Sûre, sociale, raisonnable, ce n’est plus la langue française, c’est la langue humaine

But I might be exaggerating here: if I can express more subtle things in French, it simply means that my English is too poor. I mean, in my work as a professor and a researcher, I do use English on a daily basis (reading textbooks, discussing with colleagues, or co-autors, writing research papers, etc). But blogging is just for fun… so at first, I started to blog in French.

Then, while I was giving a short course in Brazil, I understood that some students there actually did go to my blog. They were using online translation – which translated quite poorly by that time – and some asked me if I could write more posts in English. I did have also a request from Tal, the editor of http://r-bloggers.com/ who asked me to share my posts that contain R codes with the R community (i.e. non French-speaking people). So I decided to write more and more posts in English. Except perhaps posts related to my undergraduate courses.

I thought about all that recently because, while I was in Europe last week, some colleagues in Amsterdam mentioned my blog, claiming that there were (still) too many posts in French. While on the other hand, some French colleagues still ask me why I do not write only in French.

Somehow, I still find it more comfortable to write in French, especially on French related issues (e.g. politics and pools, or university related debates). But I still like the idea that my post may be interesting for students in Brazil, actuaries in the U.K. or researchers in Norway… So I guess I will try to write more posts in English. Which is not that complicated actually, since, as a French academician (or George Bernard Shaw, the source is not clear) once put it “English is a language that is relatively easy to speak poorly“. So, let’s do it….

Amsterdam, PhD defense

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Last week, I was involved in the PhD defense of Julien Tomas, with Rob Kaas (promotor), Frédéric Planchet (co-promotor), Katrien AntonioMarc Goovaerts, Ann De Schepper and Michel Vellekoop. The PhD thesis – untitled quantifying biometric life insurance risks with non-parametric smoothing methods – can be dowloaded on http://dare.uva.nl/… and on http://tel.archives-ouvertes.fr/.

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The R codes will be available soon on my blog (and on Julien’s new website http://www.likelihood.me/).

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Museum experiences, in the City

This Saturday, we had two interesting museum experiences, with the kids. Kids are 10, 7 (and a half as she keeps saying) and 2 (and a half, too). In the morning, we went to the MoMaths (which is the pun which stands for Museum of Mathematics, and sounds like MoMA) see e.g. nytimes.com/2012/12/14/arts/…, which opened mid-December.

There were a lot of exhibitions, to illustrate all kinds of mathematical concepts (as described in http://businessinsider.com/…). From a design point of view, what I did prefer was undoubtly the packing problem table. You pick up -say – five disks, and you have to pack them in – say – a triangle (an equilateral one). When you move the disks, the computer locates them and instantaneouldy computed the area of the smallest triangle which contains all of them: you have your own area, as well as the smallest one (known, so far).

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I wanted to see if kids had more intuition than I did, but even if we know the smalled area, unfortunately, we cannot see how to get it, in the museum. Of course, online, one can easily find it, e.g. for circles

for triangles,

or for squares

Nice and fun, isn’t it ? (pictures are from http://mathworld.wolfram.com/…)

About people around, you could hear two kinds of talks in the museum: “look, it’s fun, when you run, the ball is following you” (kids) or “oh, nice, as long as people move, the algorithm removes automatically nodes in the connected graphs” (former kids). Even some people decided to use sheets of paper to prove that they were correct,

And yes, everyone had fun, even my youngest daugther, who’s only 2 (and a half, I know).

We spent two hours at the MoMaths, and the kids did not want to leave. I have to admit that I was a bit relieved to leave, finally: visiting the museum was like those social events in conferences. Actually, people there were clearly people that I keep seing at work, and in conferences. But there were kids, too, so it was much more convivial. People were also drawing, like in real museums… or like during talks, in conferences. It was work, with fun (and the family). Like my blog, somehow…

Then, we went to the Guggenheim Museum. One has to admit that this is another experience. The building itself is amazing.

Guggenheim

But here, it was a more standard museum experience… Except perhaps while we where visiting the Gabriel Orozco exhibition (which was, actually, extremely interesting and reminded me Francis Alÿs ‘s work presented at MoMA last year,  http://francisalys.com/…)

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There was a guard, in a corner, and when we got too close, he asked us to move back. Trying to understand what was going on, we saw a small stone, behind him (of course “no picture, please“). The guard was waiting for a museum conservator to assess if the stone was from a shoe of a visitor, or a part of the exhibition… The conservator came look clearly at the stone, as well as others, trying to choose (if possible with conviction) whether this was a piece of art (part of the exhibition), or just a vulgar stone. True story…

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We finally left after one hour (my daughter had finished her kids activity, i.e. drawing like Picasso, comparing Picasso and Velasquez’s Meninas, and counting nuances of grays). Now, let us compare those two experiences. For instance, the visitors. At MoMaths, it was half kids, half math professors (from a personal guess), while at Guggenheim, it was more like one third tourists (with their NY Yankees cap, just to pretend they aren’t tourists… which is exactly what I do), and two third retired upper-class New Yorkers (including some much youger models in the arms of golden boys). At MoMaths, most of them were English speakers (and they had to, beacuse it was quite difficult to get information in another language, unfortunately), but at Guggenheim, I heard a lot of French, Italian, even Dutch… The public in those two museums were completely different.

When discussing with kids afterwards, we wanted to know which museum they did prefer. Without any doubts, the answer was MoMaths. And when we asked them in which museum the freakiest people were, they both said the Guggenheim museum. Maybe I am not really a freak, after all, at least in my kids eyes…