In the US, sometimes at Mass I see people quietly playing angry birds or scrabble on their iPhone during the homily. France I thought had been preserved until now. But at midnight Mass here in France, I saw a man texting on his phone immediately after receiving communion, while others were still standing in line for communion.
Are there no limits to that need to be constantly connected?
When are people not connected?
As far as I know, the shower might be the last refuge against the invasion of technology. I have yet to see a gadget to send email while showering.
Sunday, December 25, 2011
Friday, December 23, 2011
Learning Algorithms online
No, this is not about online algorithms, nor about learning theory.
I have signed up for Tim Roughgarden's online course on Algorithms, http://www.algo-class.org
One might wonder why I need to learn about divide-and-conquer, searching, quicksort and shortest paths. In fact, I'll be teaching Algorithms myself at the same time. What's wrong with me? Do I plan to steal Tim's lectures and repeat them verbatim to my students, thus sparing myself the need to understand the material? Have I been secretly incompetent during all the years during which I pretended to teach the material, and is this a remedial course to finally patch my ignorance in my alleged area of expertise? Am I so stingy that I can't refuse something that is offered for free? Or have I so bought into the school system of grades and diplomas that I can't pass on the chance for an easy way to get one more certificate? In a few months I will be able to add it to my vita, and perhaps it'll help me get a raise. Or do I enjoy criticizing other people so much that I'm going be watching those videos of Tim and snickering, and then posting on my blog nasty comments about every slip that might occur? Am I secretly in love with Tim, or do I secretly bear a grudge against him?
None of those reasons. I am curious to see someone else teach the same material that I teach. I look forward to the ability of fast-forwarding the parts I have down pat, and paying careful attention to the material which I have trouble conveying to my students. Perhaps I can use some of it to improve my own teaching.
Additionally, I am curious to see how the Stanford online courses work in practice, with the thought, in the back of my mind, that perhaps I will also engage in online teaching in the future, if the technology is user-friendly enough. The idea of higher education freely available to all in that manner is fascinating, and experiencing how it plays out on a familiar subject might help me understand the strong points and the weaknesses of the approach.
I have signed up for Tim Roughgarden's online course on Algorithms, http://www.algo-class.org
One might wonder why I need to learn about divide-and-conquer, searching, quicksort and shortest paths. In fact, I'll be teaching Algorithms myself at the same time. What's wrong with me? Do I plan to steal Tim's lectures and repeat them verbatim to my students, thus sparing myself the need to understand the material? Have I been secretly incompetent during all the years during which I pretended to teach the material, and is this a remedial course to finally patch my ignorance in my alleged area of expertise? Am I so stingy that I can't refuse something that is offered for free? Or have I so bought into the school system of grades and diplomas that I can't pass on the chance for an easy way to get one more certificate? In a few months I will be able to add it to my vita, and perhaps it'll help me get a raise. Or do I enjoy criticizing other people so much that I'm going be watching those videos of Tim and snickering, and then posting on my blog nasty comments about every slip that might occur? Am I secretly in love with Tim, or do I secretly bear a grudge against him?
None of those reasons. I am curious to see someone else teach the same material that I teach. I look forward to the ability of fast-forwarding the parts I have down pat, and paying careful attention to the material which I have trouble conveying to my students. Perhaps I can use some of it to improve my own teaching.
Additionally, I am curious to see how the Stanford online courses work in practice, with the thought, in the back of my mind, that perhaps I will also engage in online teaching in the future, if the technology is user-friendly enough. The idea of higher education freely available to all in that manner is fascinating, and experiencing how it plays out on a familiar subject might help me understand the strong points and the weaknesses of the approach.
My other theory on grades
Assignments are either for helping the students learn, or for evaluating them. Grades are either to give them an incentive to do the work involved in learning, or to evaluate them. Two very different goals!
For evaluation purposes, grades give the maximum information is the distribution has maximum entropy, so ideally there ought to be about 1/3 A's, 1/3 B's, and 1/3 C's.
For evaluation purposes, assignments are most useful if they help distinguish students from one another, so the ideal exercise is at the right level of difficulty so as to be solvable by exactly half of the students. An exercise that is successfully done by all serves no purpose for evaluation. An exercise that almost no one can do may still serve a purpose: that of distinguishing the few students who stand out by their ability to solve a problem that the vast majority could not do. Exercises with a variety of difficulty levels help evaluate more finely. Since the primary goal of midterms and finals is to evaluate, that's how they should be designed, and the median grade for those would probably be around 50. In fact, that's more or less how things are done in France. The learning part happens in exercises that are not graded, and the sole purpose of grading is to evaluate.
In the US, my experience is that assignments are usually designed so that, with enough time, most students can do most of the assignment: their primary purpose is to help the student learn. A very different perspective!
For evaluation purposes, grades give the maximum information is the distribution has maximum entropy, so ideally there ought to be about 1/3 A's, 1/3 B's, and 1/3 C's.
For evaluation purposes, assignments are most useful if they help distinguish students from one another, so the ideal exercise is at the right level of difficulty so as to be solvable by exactly half of the students. An exercise that is successfully done by all serves no purpose for evaluation. An exercise that almost no one can do may still serve a purpose: that of distinguishing the few students who stand out by their ability to solve a problem that the vast majority could not do. Exercises with a variety of difficulty levels help evaluate more finely. Since the primary goal of midterms and finals is to evaluate, that's how they should be designed, and the median grade for those would probably be around 50. In fact, that's more or less how things are done in France. The learning part happens in exercises that are not graded, and the sole purpose of grading is to evaluate.
In the US, my experience is that assignments are usually designed so that, with enough time, most students can do most of the assignment: their primary purpose is to help the student learn. A very different perspective!
Thursday, December 22, 2011
My theory on grades
I wish students typically got a B in my course.
C's would be reserved to the students who stand out because they're at the lower tail of the distribution (something of the order of 5 percent of the students), and
A's would be reserved to the students who stand out because they're at the upper tail of the distribution (also something of the order of 5 percent).
This way students would expect to get a B, the bulk of the students would get the grade which they expected to get, and the occasional A would be a pleasant surprise.
As it happens, this semester my class was so good and hard-working that I gave a very large number of A's (40 percent!!), which meant that the cutoff point fell in the dense part of the distribution of grades, which meant that it was rather arbitrary: between the 20 "A students" with lowest average grade, and the 20 "B students" with highest average grade, I bet that the difference in performance is statistically completely insignificant. That's a lot of students who will curse their bad luck or question my judgment!
But even for next semester, I don't dare try my theory. B versus A grades don't really matter very much anyway for Brown CS students. The expectation is that they work hard, learn well, and get a good education. Whether that means giving A's to the majority (because we're so pleased with them), or giving B's to the majority (because they're doing as expected, and it's difficult for a student to stand out in an environment in which most are putting so much effort into their coursework), really does not matter much.
C's would be reserved to the students who stand out because they're at the lower tail of the distribution (something of the order of 5 percent of the students), and
A's would be reserved to the students who stand out because they're at the upper tail of the distribution (also something of the order of 5 percent).
This way students would expect to get a B, the bulk of the students would get the grade which they expected to get, and the occasional A would be a pleasant surprise.
As it happens, this semester my class was so good and hard-working that I gave a very large number of A's (40 percent!!), which meant that the cutoff point fell in the dense part of the distribution of grades, which meant that it was rather arbitrary: between the 20 "A students" with lowest average grade, and the 20 "B students" with highest average grade, I bet that the difference in performance is statistically completely insignificant. That's a lot of students who will curse their bad luck or question my judgment!
But even for next semester, I don't dare try my theory. B versus A grades don't really matter very much anyway for Brown CS students. The expectation is that they work hard, learn well, and get a good education. Whether that means giving A's to the majority (because we're so pleased with them), or giving B's to the majority (because they're doing as expected, and it's difficult for a student to stand out in an environment in which most are putting so much effort into their coursework), really does not matter much.
Wednesday, December 21, 2011
First impressions of Paris after a transatlantic red-eye.
As the airplane approaches, we see mostly darkness, punctuated by village and highway lights. In the distance, the City of Lights: a beneath a light veil-like cloud, a large cluster of dense, very bright lights, whose reflection in the dark gives the cloud a yellowish, almost golden appearance. I am musing on how funny it is that the cloud picked precisely Paris to hand over, not the surrounding countryside; I note that the cloud is much lighter than the occasional black clouds between us and the land down below. Then it hits me: it's smog!
Paris is choking in air pollution.
In the airport hallway, large signs on the sides advertised Paris. The first sign: Eiffel tower, Champs-Elysees,... Parisian monuments. The second sign: Opera, jazz, ... (meanwhile background music had Edith Piaf and then accordeon music). The third sign: strolls along the river, romantic scenery, used book shops by Notre Dame,... That was it. This is Paris! Nothing about La Defense, about businesses, or about the people living and working there. It looked like a pure tourist destination and nothing else.
Paris markets itself as merely a more authentic version of Disneyland.
At 8am in Paris, the subways were full of people standing close to one another, some fraction of them sniffing, sneezing or coughing. Colds and minor epidemics plague Parisians all winter long, in ways unknown to Rhode Islanders.
Paris is the Kingdom of Kleenex.
I had the usual hassles with unhelpful staff and buggy official information, no big deal but annoying and a waste of time.
In Paris, when something works right and easily at the first attempt, you stop in wonder and give thanks to God for that small miracle.
Paris is choking in air pollution.
In the airport hallway, large signs on the sides advertised Paris. The first sign: Eiffel tower, Champs-Elysees,... Parisian monuments. The second sign: Opera, jazz, ... (meanwhile background music had Edith Piaf and then accordeon music). The third sign: strolls along the river, romantic scenery, used book shops by Notre Dame,... That was it. This is Paris! Nothing about La Defense, about businesses, or about the people living and working there. It looked like a pure tourist destination and nothing else.
Paris markets itself as merely a more authentic version of Disneyland.
At 8am in Paris, the subways were full of people standing close to one another, some fraction of them sniffing, sneezing or coughing. Colds and minor epidemics plague Parisians all winter long, in ways unknown to Rhode Islanders.
Paris is the Kingdom of Kleenex.
I had the usual hassles with unhelpful staff and buggy official information, no big deal but annoying and a waste of time.
In Paris, when something works right and easily at the first attempt, you stop in wonder and give thanks to God for that small miracle.
Tuesday, December 20, 2011
The experience of reading a paper
Trying to read a proof in depth (say, because I was preparing a blog post on it), the reader may go through various feelings in sequence.
1. Stupidity; How come I don't understand it at all? Am I becoming stupid?
2. Anger and frustration; how come the authors leave some definitions ambiguous, and why did the referee not send the paper back to ask for another round of polishing?
3. An idea: let me just look for slides of a talk on the subject! Slides usually put much more emphasis on intuition and might help me understand what the authors meant to say.
4. Obstination; I can do it. There are no slides available, but I'm interested in the result and just need to put my mind to it. Go through examples systematically, try out the various interpretations until one fits and the proof goes through.
5. Suspicion. Is that result really correct? None of my interpretations seem to work.
6. Discouragement; I can't do it. I'll have to look up references of prior work and see which ideas are present in there and whether they are explained any better. This is turning into a major time sink.
As an intellectual activity, reading technical text is really not much different from doing research.
1. Stupidity; How come I don't understand it at all? Am I becoming stupid?
2. Anger and frustration; how come the authors leave some definitions ambiguous, and why did the referee not send the paper back to ask for another round of polishing?
3. An idea: let me just look for slides of a talk on the subject! Slides usually put much more emphasis on intuition and might help me understand what the authors meant to say.
4. Obstination; I can do it. There are no slides available, but I'm interested in the result and just need to put my mind to it. Go through examples systematically, try out the various interpretations until one fits and the proof goes through.
5. Suspicion. Is that result really correct? None of my interpretations seem to work.
6. Discouragement; I can't do it. I'll have to look up references of prior work and see which ideas are present in there and whether they are explained any better. This is turning into a major time sink.
As an intellectual activity, reading technical text is really not much different from doing research.
Friday, December 16, 2011
On applying for jobs
At this time of year, I often get contacted by potential job applicants. It is often quite difficult to gauge how interested I might be in their application, just by looking at their vita or trying to read one of their papers (and who has time to do more than that.) Arranging to meet with them is usually a big hassle for one or the other party, since they are seldom local.
What would help me would be if I saw them give a talk. For me a talk is much more informative than a paper and with much less effort. But how can that happen without the bother of traveling?
Simple: job applicants could simply videotape themselves giving their job talk, and post it on their web page.
Then I could simply download and watch their talk, and in 50 minutes I would have a good idea of their research, of how interested I am in it, and of how good they are at communicating. That would be great for me!
Why not?
What would help me would be if I saw them give a talk. For me a talk is much more informative than a paper and with much less effort. But how can that happen without the bother of traveling?
Simple: job applicants could simply videotape themselves giving their job talk, and post it on their web page.
Then I could simply download and watch their talk, and in 50 minutes I would have a good idea of their research, of how interested I am in it, and of how good they are at communicating. That would be great for me!
Why not?
Wednesday, December 14, 2011
The in-between time
I am in a transition week. The lectures of the semester are over, but final grades have not yet been calculated and turned in. I have a few days of delicious freedom to catch up with the semester's unfinished business before heading home for Christmas. It's a time to wrap things up, archive the semester's work, and assign priorities to tasks for the break.
A similar transition week happens just before the first day of classes of each semester. People plan their lectures, their travels, and organize the semester.
Transition periods are wonderful. I think that they are key to being in control of one's professional life.
When I was a professor in France, there was no clean break between semesters. The Fall semester ran well into January, and the last meetings and unresolved questions related to the Fall semester overlapped with the beginning of the Spring semester. As for the summer, one of the worst things about it was that it ended, not merely with the preparation of the Fall, but also with make-up exams for students who had failed in the Spring and who had spent the summer studying. Because of those make-up exams, there was a continuum of teaching-related tasks, with never a chance for a reboot.
Transition periods happen at all time scales. For example, google calendars offers the option of planning hour-long meetings so that they're actually 50 minutes long. That gives time for a bathroom and coffee break between meetings. Brilliant idea!
A similar transition week happens just before the first day of classes of each semester. People plan their lectures, their travels, and organize the semester.
Transition periods are wonderful. I think that they are key to being in control of one's professional life.
When I was a professor in France, there was no clean break between semesters. The Fall semester ran well into January, and the last meetings and unresolved questions related to the Fall semester overlapped with the beginning of the Spring semester. As for the summer, one of the worst things about it was that it ended, not merely with the preparation of the Fall, but also with make-up exams for students who had failed in the Spring and who had spent the summer studying. Because of those make-up exams, there was a continuum of teaching-related tasks, with never a chance for a reboot.
Transition periods happen at all time scales. For example, google calendars offers the option of planning hour-long meetings so that they're actually 50 minutes long. That gives time for a bathroom and coffee break between meetings. Brilliant idea!
Tuesday, December 13, 2011
Organizing recommendation letters
A novelty this year: I have several students who have created a google document in excel format listing the places where they have applied, how to send a recommendation letter, and a column for each letter writer to mark when they actually do send the recommendation letter.
I find it convenient. I no longer have to worry about whether I accidentally missed one of the requests. They no longer have to worry about reminding us uselessly.
In addition this gives us new data to mine: when do the various schools send their requests for recommendation letters? How prompt are my various colleagues in responding to those requests? It's all there for us to see. Of course it's not clear what to do with that interesting data. Maybe it's useless knowledge, but I like it anyway. Plus, in our race to the bottom, it's making me realize that I am not the most disorganized: I still have room to spare!
I find it convenient. I no longer have to worry about whether I accidentally missed one of the requests. They no longer have to worry about reminding us uselessly.
In addition this gives us new data to mine: when do the various schools send their requests for recommendation letters? How prompt are my various colleagues in responding to those requests? It's all there for us to see. Of course it's not clear what to do with that interesting data. Maybe it's useless knowledge, but I like it anyway. Plus, in our race to the bottom, it's making me realize that I am not the most disorganized: I still have room to spare!
Monday, December 12, 2011
On naming files
Last week I renamed my files containing the slides of my lectures for this past semester. I had started the semester by naming them: "lecture1", "lecture2", "lecture3", etc. At some point I lost track, and started using dates instead: "october25", "october28", etc. Now I wanted to given them a name that would be helpful, should I look them up again in the future.
Should I call them by their number - lecture1 through lecture35? Not so good, because I may want on some future day to look up the lecture about, say, quick sort, and with that labeling I have no easy way to know where those slides are.
Should I call them by their topic - "Ocamlpatternmatching", "quick sort", etc.? Not so good, because there is a logical order that is lost when I do that.
Should I call them by a combination - "15_higherorderprocedures", "25_runtimeanalysis", etc.? Pretty good, except for one minor flaw: when I list the files in the directory, they do not appear in the correct order: 12blabla precedes 2blabla.
So I ended up calling them by a combination, by started the numbering at 100: "115_higherorderprocedures", "125_runtimeanalysis", etc.
The result looks pretty good. It only took me 25 years of professional experience to figure that out. How come no one has ever taught me how to organize my files? Did I miss a class on "remedial organization" at some point?
Should I call them by their number - lecture1 through lecture35? Not so good, because I may want on some future day to look up the lecture about, say, quick sort, and with that labeling I have no easy way to know where those slides are.
Should I call them by their topic - "Ocamlpatternmatching", "quick sort", etc.? Not so good, because there is a logical order that is lost when I do that.
Should I call them by a combination - "15_higherorderprocedures", "25_runtimeanalysis", etc.? Pretty good, except for one minor flaw: when I list the files in the directory, they do not appear in the correct order: 12blabla precedes 2blabla.
So I ended up calling them by a combination, by started the numbering at 100: "115_higherorderprocedures", "125_runtimeanalysis", etc.
The result looks pretty good. It only took me 25 years of professional experience to figure that out. How come no one has ever taught me how to organize my files? Did I miss a class on "remedial organization" at some point?
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