Thursday, September 30, 2010

Kittens and fleas

I am acquiring valuable knowledge on cat fleas. This time I have figured out that the kittens I'm fostering have fleas, before I got bitten even once.
1. They groom themselves more often than I am comfortable with
2. I closely examine the fur of the whitest kitten and spot some suspicious specks of black dirt
3. I pluck one speck, put it on a piece of white paper, wet it with water, wait a few moments: it dissolves and becomes reddish. That's the proof! It's not dirt, but flea excrement, made from kitten blood. How strangely gratifying it is to witness the definitive confirmation of one's fears.

Now that I have a head start on identifying the problem, I should be able to control it before we get infested. I hope.

Wednesday, September 29, 2010


The other night in downtown Providence, on Kennedy Plaza, I saw an older homeless couple. The man was carrying several heavy bags, and the woman was pulling a carriage. They crossed the street slowly, with slightly shuffling steps. On the other side, as the woman was having trouble pulling her carriage up, the man turned to her, saw what was delaying her, gently took the handle from her and pulled the carriage up the curb. They then resumed their share of the load and their slow walk.

A few minutes later, I saw them again, wandering back by the park, indistinct in the shadows but recognizable by their uncertain gait, before they finally disappeared out of sight.

Friday, September 24, 2010

More on technology

One more thing to worry about: I must not accidentally misplace my tablet pen - else lecture preparation becomes a real challenge!

A small miracle happened today: setting up my (borrowed) tablet in an unknown classroom with unfamiliar technological equipment, I followed the directions printed by the projector etc., pushed the buttons that had a big highlighted label, according to directions, and everything worked without a hitch. Amazing.

The alternative would have been a black board, and I hate chalk dust, so I was highly motivated to do it right.

Wednesday, September 22, 2010

How to take a break, past and present

After intensive work for a couple of hours, I am usually mentally exhausted and need a short break.

Nowadays: I get some coffee and surf the web idly.

In the old days: I got some coffee and sat by the coffee machine to chat with whoever else was taking a break at that time.

Does the web make us socialize less with the people who work just down the hall from us?

Saturday, September 18, 2010

The problem with technology

- Must not lose my tablet charger
- Must not get my tablet pen stuck inside the tablet
- Must not get my laptop separated into two pieces after going through customs in checked luggage
- Must not wash my cell phone in the washing machine
- Must not forget my apple laptop connector when giving a talk
Why are we so worried about software? Hardware is the problem.

Saturday, September 11, 2010


Flying on September 11: just like any other day.

One of the most popular and lively conversation topics among computer science researchers: the comparative qualities of various airports. Many people would think we're dreadful snobs showing off our travels, but that's not the reason: we're simply disconnected from the reality of a world in which, for many, flying is still a very rare treat. When I am not in the company of fellow academics, I have learnt to refrain from complaining about the unpleasantness of air travel; in fact, best to avoid mentions of air travel altogether.

Friday, September 10, 2010


Liverpool, UK. Outside the hotel there is a small plaza shaped like a mini roman amphitheater. I stood in the center and spoke up. The acoustics made my voice resonate as if I had a microphone. Incredible.

The Thai restaurant where we had dinner had a big fish pond next to our table with goldfish swarming, obviously eagerly waiting to be fed. I gave them some bits of the flower that was in a vase on our table, and they ate it hungrily. As soon as my hand approached the surface of the water, they all rushed towards it, mouths wide open. It's almost scary!

Wednesday, September 8, 2010

Email surge

During most of August, thanks to slow internet traffic and more time to clean up my desk, I was able to contain the size of my mailbox to about 50 or less. Now, with the new semester starting, in spite of my efforts the number of messages has shot up to over 100.

Email seem impossible to contain more than temporarily. It's like malaria --with constant care, it's possible to contain it in spite of occasional feverish bouts, but it's always threatening to overwhelm at the next crisis.

Monday, September 6, 2010

May 1

Today is May 1, or rather, Labor day, the US analog. But here it is a chance to exalt work as an ethical (?) value, not to review inequalities at work nor to have street demonstrations.

Classes at Brown start on Wednesday September 1, but Monday September 6 is a holiday in the US (it's their version of May 1), complicating the schedule already in the first week. It's odd how the semester begins: three days of classes, and then immediately a long weekend. Why not start on Tuesday September 7?

I don't think it's by chance. The same thing happens every year in the local high school. It must be by design. But what's the reason?

Friday, September 3, 2010

CS 17: a learning experience

What I learned today in class:
- that writing code on a screen in real time is horrendous. I should always have the next slide ready with the resulting code, so that after my efforts to write, a cleaner and complete version appears on the next screen.
- that freshmen have never seen truth tables before!!

What I already knew but learned again:
- that rushing to cover planned material before the end of class is not worth it! Better go slowly and carefully.

Thursday, September 2, 2010


I dislike technology. Only in 2005 did I reluctantly shift from using transparencies to computer slides. But the tablet enables me to go backwards in time. Now I can use a pen, see my own handwriting appear on the screen, and update the content of the slide during the lecture as I see fit. Soon we'll be able to do without mouse or keyboard altogether. I am thrilled!

Current students, however, might not be so thrilled since they grew up with keyboards and do not resent their presence, so there is only a small window of opportunity for tablet development before the pen-loving generations disappear.

Next goal: when will we go backwards to the time of my beloved fountain pen?

Wednesday, September 1, 2010

Defining constants

To day in class I showed an example of constant definition in Racket (formerly Scheme)

Student's question: Can you change it later?

Answer: no, you define that identifier once and for all. Once chosen, you cannot change it. It's like a baptism.

Actually that's not quite true, in fact it's the reverse. If a child is baptized "David", then his name will be David forever. But it is possible to use the name "David" for other children.

In Racket when you write: (define myfavoriteconstant 45), you take a number: 45, and give it a name: "myfavoriteconstant". From now on "myfavoriteconstant" refers to 45; that cannot be changed. However, nothing prevents you from choosing other names as well: you may next write
(define ilikethisnametoo 45)

First class of the semester

I was teaching using a tablet PC today, for the first time; the tablet is borrowed from a colleague.

What I learnt today: in order to connect with the projector, I should press Function F4.

What I could have done better: I could have learnt this earlier than 10 minutes into class.