Some time ago I received an email asking if I had any opinion on how to enjoy writing papers. That's a tough question. We usually fumble trying to come up with a good problem, struggle while having some fun formulating a good conjecture, delight in trying to solve it, and finally have a painful time writing the resulting paper. How can we make the writing stage less painful?
One thing I learned recently about this, is that it is not a good idea to try to fit writing into the cracks of free time, and not to delay until the environment is not favorable to problem-solving. I had one visitor come for a month -- four weeks: we spent three weeks plus a little bit working on formulating and solving a problem, then he declared, to my surprise, that he would spend the last three or four days of his stay writing up what we had done. It was the right thing to do, of course. For busy people, it's a really smart idea to plan significant time for writing hand in hand with problem-solving!
Another thing I learned is that giving talks helps while writing. It helps clarify one's thoughts and maintain one's interest.
Ideally, I suppose that with self-discipline one would maintain writings of one's work during the process of doing the research, but it's real work to incorporate a day's discussions in a file in an intelligent way, synthesizing it with previous notes and remarks so that the file does not grow out of bounds in a chaotic manner. Still, my impression is that writing is more fun if it happens at the same time as problem-solving, in spite of knowing that everything will probably need to be rewritten at some later time.
Are there good tips from the world of programming? Not tips to write well-organized, coherent, clear papers, but tips to write in a way that keeps that activity enjoyable (or at least, enjoyable to some degree) at every stage.
Tuesday, May 31, 2011
Monday, May 30, 2011
Memorial day weekend
This is Memorial day weekend, during which Americans celebrate their veterans and remember their war dead. The liberation of France is the first reason why I have so much admiration for Americans (and the British and the Allies, of course). Here is an excerpt of a journal entry written by my grandfather (my father's father), describing the joy of the population at the liberation of Versailles. A book gathering his writings about being a professor at the Sorbonne during the Occupation has been submitted for publication.
Vendredi 25.
Au réveil, soleil radieux et silence complet sur Versailles. A peine quelques bruits de canon très lointain. Une fumée s’élève dans le Nord. Qui est vainqueur ?
A 9h, nous sortons mon fils et moi. [...] Un avion de reconnaissance canadien est tombé avenue de Paris devant le lycée de jeunes filles [dès l’après-midi, son fuselage est couvert de fleurs et de rubans.]. [...] Sur l’avenue de Paris, la foule se presse, plus dense qu’on ne l’a jamais vue aux plus grands jours de fête (aujourd’hui 25 août, fête de Saint Louis, patron de Versailles).
10h50. Débouchant de l’avenue Thiers (à présent ‘Avenue du Général de Gaulle), venant de Rambouillet où ils ont été alertés hier matin, les motorisés de la division Leclerc (spahis marocains, fusiliers marins, éléments du 3e régiment de marche du Tchad) apparaissent. Les acclamations redoublent, si fortes qu’elles couvrent la voix des haut-parleurs. La ruée de la foule est telle que les chars doivent s’arrêter. Les jeunes gens, les jeunes filles, les enfants acclament les chars, couvrent de fleurs et de baisers les hommes, les uns presque enfants à figure rose, les autres (sans doute les anciens du Tchad et de Libye) tannés par le soleil. Les soldats, étourdis par les acclamations, se bouchent les oreilles, jettent à la foule cigarettes, tablettes de chocolat, boites de lait condensé. Le colonel commandant la colonne [note: Lieutenant-Colonel Rémi, des spahis marocains.] paraît à la fenêtre de la salle des fêtes de l’hôtel de ville et prononce une allocution si hachée d’acclamations qu’on n’en entend que quelques mots. Un disque diffuse la Marseillaise ; mais les gorges, enrouées d’acclamations ou d’émotion peuvent à peine l’accompagner. Mon fils applaudit frénétiquement, agite son éventail tricolore, hurle : « Bravo ! ». Les enfants sont les plus enragés ; depuis quinze jours ils sont accrochés à la TSF ou préparent les drapeaux, drapeaux fanés ressortis des greniers ou des caves, ou bien morceaux de linge blanc passés hâtivement à la peinture ou au crayolor. [...]
A 21hs 30, nous nous rendons devant la mairie où stationne une foule un peu moins dense que le matin, mais tout aussi enthousiaste. On a retrouvé de la voix pour chanter la Marseillaise . Des haut-parleurs diffusent marches et chansons militaires. Les pompiers ont mis en marche leur groupe électrogène de secours et illuminent la façade de la mairie écornée par l’attaque allemande du 24. Tous les éléments jeunes (soldats de Leclerc dont les voitures stationnent aux environs, pompiers, jeunes gens de la D P, secouristes de la Croix Rouge) se prennent par la main et partent en une immense farandole (note: Le lendemain les pompiers de service prétendront avoir retrouvé 35 talons de souliers dans la cour de la mairie). A 22hs 15, une nouvelle Marseillaise ; puis l’on se retire pendant que les F F I s’organisent en postes de garde.
Friday, August 25. In the morning, the sun is bright and there is complete silence over Versailles. We barely hear the very distant sound of a canon, and see smoke on the North side. Who is the winner? At 9am, my son and I leave the house. A Canadian scouting airplane has fallen on the street "avenue de Paris" in front of the girls' high school. (In the afternoon, it will be covered by flowers and ribbons.) On the street, a great crowd is pressing, denser than I have ever seen it (today August 25 is the feast of Saint Louis, the patron saint of Versailles.) At 10:50am, arriving from "avenue Thiers", coming from Rambouillet, the first tanks from the Leclerc division appear: Moroccan spahis, marine shooters, members of the 3rd infantery regiment of Chad. The cheers from the crowd redouble, so loud that they drown the voice on the loud speakers. The crowd is rushing forth with such eagerness that the tanks must stop. Young men, young women, children cheer at the tanks, cover with flowers and kisses the soldiers, some still almost children with pink faces, others (probably Chad or Lybia veterans) deeply sun-tan. The soldiers, overwhelmed by the acclamations, cover their ears. They throw to the crowd cigarettes, chocolate bars, boxes of condensed milk. The colonel leading the troops (note: Lieutenant-Colonel Rémi from the Moroccan spahis) appears at the window of the city hall and gives a speech accompanied by such cheers that we only hear a few words. A record is playing the "Marseillaise", but the people, their throats hoarse from cheering and emotion, can barely sing along. My son claps frenetically, waving a French flag, screaming: "Bravo!". The children are the most excited. For the past two weeks they have been listening ceaselessly to the radio and preparing French flags, old flags taken out of dusty attics or basements, or pieces of white cloth hastily covered with paint or felt pen. [...] At 9:30pm, we go to the city hall where the crowd is slightly less dense than in the morning, but just as enthusiastic. We have found our voice again to sing the Marseillaise. Loud-speakers sound off marches and military music. The firemen use their backup electricity equipment to illuminate the building, slightly damaged by the German attack of the 24th. All the young people (soldiers from the Leclerc division, whose cars are parked nearby, firemen, young men from the civil protection, Red Cross workers) hold hands and form a gigantic farandole (note: on the next day, the firemen claim to find 35 shoe heels in the city hall courtyard). At 10:15pm, another Marseillaise: then we go home while the Resistance sets up the night watch.
Vendredi 25.
Au réveil, soleil radieux et silence complet sur Versailles. A peine quelques bruits de canon très lointain. Une fumée s’élève dans le Nord. Qui est vainqueur ?
A 9h, nous sortons mon fils et moi. [...] Un avion de reconnaissance canadien est tombé avenue de Paris devant le lycée de jeunes filles [dès l’après-midi, son fuselage est couvert de fleurs et de rubans.]. [...] Sur l’avenue de Paris, la foule se presse, plus dense qu’on ne l’a jamais vue aux plus grands jours de fête (aujourd’hui 25 août, fête de Saint Louis, patron de Versailles).
10h50. Débouchant de l’avenue Thiers (à présent ‘Avenue du Général de Gaulle), venant de Rambouillet où ils ont été alertés hier matin, les motorisés de la division Leclerc (spahis marocains, fusiliers marins, éléments du 3e régiment de marche du Tchad) apparaissent. Les acclamations redoublent, si fortes qu’elles couvrent la voix des haut-parleurs. La ruée de la foule est telle que les chars doivent s’arrêter. Les jeunes gens, les jeunes filles, les enfants acclament les chars, couvrent de fleurs et de baisers les hommes, les uns presque enfants à figure rose, les autres (sans doute les anciens du Tchad et de Libye) tannés par le soleil. Les soldats, étourdis par les acclamations, se bouchent les oreilles, jettent à la foule cigarettes, tablettes de chocolat, boites de lait condensé. Le colonel commandant la colonne [note: Lieutenant-Colonel Rémi, des spahis marocains.] paraît à la fenêtre de la salle des fêtes de l’hôtel de ville et prononce une allocution si hachée d’acclamations qu’on n’en entend que quelques mots. Un disque diffuse la Marseillaise ; mais les gorges, enrouées d’acclamations ou d’émotion peuvent à peine l’accompagner. Mon fils applaudit frénétiquement, agite son éventail tricolore, hurle : « Bravo ! ». Les enfants sont les plus enragés ; depuis quinze jours ils sont accrochés à la TSF ou préparent les drapeaux, drapeaux fanés ressortis des greniers ou des caves, ou bien morceaux de linge blanc passés hâtivement à la peinture ou au crayolor. [...]
A 21hs 30, nous nous rendons devant la mairie où stationne une foule un peu moins dense que le matin, mais tout aussi enthousiaste. On a retrouvé de la voix pour chanter la Marseillaise . Des haut-parleurs diffusent marches et chansons militaires. Les pompiers ont mis en marche leur groupe électrogène de secours et illuminent la façade de la mairie écornée par l’attaque allemande du 24. Tous les éléments jeunes (soldats de Leclerc dont les voitures stationnent aux environs, pompiers, jeunes gens de la D P, secouristes de la Croix Rouge) se prennent par la main et partent en une immense farandole (note: Le lendemain les pompiers de service prétendront avoir retrouvé 35 talons de souliers dans la cour de la mairie). A 22hs 15, une nouvelle Marseillaise ; puis l’on se retire pendant que les F F I s’organisent en postes de garde.
Friday, August 25. In the morning, the sun is bright and there is complete silence over Versailles. We barely hear the very distant sound of a canon, and see smoke on the North side. Who is the winner? At 9am, my son and I leave the house. A Canadian scouting airplane has fallen on the street "avenue de Paris" in front of the girls' high school. (In the afternoon, it will be covered by flowers and ribbons.) On the street, a great crowd is pressing, denser than I have ever seen it (today August 25 is the feast of Saint Louis, the patron saint of Versailles.) At 10:50am, arriving from "avenue Thiers", coming from Rambouillet, the first tanks from the Leclerc division appear: Moroccan spahis, marine shooters, members of the 3rd infantery regiment of Chad. The cheers from the crowd redouble, so loud that they drown the voice on the loud speakers. The crowd is rushing forth with such eagerness that the tanks must stop. Young men, young women, children cheer at the tanks, cover with flowers and kisses the soldiers, some still almost children with pink faces, others (probably Chad or Lybia veterans) deeply sun-tan. The soldiers, overwhelmed by the acclamations, cover their ears. They throw to the crowd cigarettes, chocolate bars, boxes of condensed milk. The colonel leading the troops (note: Lieutenant-Colonel Rémi from the Moroccan spahis) appears at the window of the city hall and gives a speech accompanied by such cheers that we only hear a few words. A record is playing the "Marseillaise", but the people, their throats hoarse from cheering and emotion, can barely sing along. My son claps frenetically, waving a French flag, screaming: "Bravo!". The children are the most excited. For the past two weeks they have been listening ceaselessly to the radio and preparing French flags, old flags taken out of dusty attics or basements, or pieces of white cloth hastily covered with paint or felt pen. [...] At 9:30pm, we go to the city hall where the crowd is slightly less dense than in the morning, but just as enthusiastic. We have found our voice again to sing the Marseillaise. Loud-speakers sound off marches and military music. The firemen use their backup electricity equipment to illuminate the building, slightly damaged by the German attack of the 24th. All the young people (soldiers from the Leclerc division, whose cars are parked nearby, firemen, young men from the civil protection, Red Cross workers) hold hands and form a gigantic farandole (note: on the next day, the firemen claim to find 35 shoe heels in the city hall courtyard). At 10:15pm, another Marseillaise: then we go home while the Resistance sets up the night watch.
Sunday, May 29, 2011
How to test blog moderation?
I discovered two days ago how to change the settings of this blog to allow anonymous comments, which I did. The next day, an anonymous comment appeared (about the move to living in virtual reality): "you still have to go number 2 physically though ... " Thus I am immediately faced with a deep, fascinating question: to delete or not to delete, that is the question.
I occasionally participate in blogs, and my comments often get deleted. For example, once I tried to put a comment on Archbishop Dolan's blog, correcting some information (about the sexual abuse scandal, if memory serves) by giving a few facts, with links to supporting documents. But my comment never appeared. I was surprised because it expressed no opinion and only stated facts. How can one object to that? That blog sometimes contains criticisms in the comments, so I had not thought that comment moderation was unfair. I spent a few days observing the blog regularly after that, and now have a conjecture: the moderator lets through a balance of positive and begative comments, but biases them so that the negative comments are emotional rants rather than rational arguments. It gives the illusion of being open-minded while subtly veering readers in a certain direction. If my theory is true, that's a pretty sneaky manipulation!
Another time, on a similar site, I tried to post a comment. I knew the moderator was ruthless in deleting whatever he didn't like, so I tried to game the system by posting a quote from his own writing, carefully chosen so that in the context of his post it would be a subtle rebuttal of his rant. I figured that he surely would feel guilty about deleting that post, and was hoping to pass his filter successfully because of that. I naively thought I was being clever. What happened next was impressive: my comment got marked as "waiting to be moderated" before appearing... but half a day later. So, yes, it did appear. But by that time, many readers had moved on to some other topic. Additionally, it appeared at the place in the list of comments where I had originally posted it, so it was buried deep underneath all the comments that appeared in the intervening twelve hours, and so I expect that no one read it. Clever! He outwitted me.
So, the main purpose of moderation is propaganda: then moderation is most effective if it does not consist in stupidly deleting everything that does not fit the moderator's agenda, but in letting some carefully filtered, well-chosen criticism go through.
I have lost a lot of my excitement about blogs as measuring the pulse of public opinion, when I realized that comments do not express the vox populi but the moderator's portrayal of the vox populi. It's a sham.
One burning question: how to test such theories? I would love to see some formal study of blog moderation, preferably extended to information control in general. How can the user figure out whether a blog is biased, and how badly? In both of the above examples, I realized it by mere chance, and I did not repeat the experiment. What about blogs that claim to follow certain rules for moderation: how can we verify that they follow the stated rules, when we do not get to see the deleted comments?
I occasionally participate in blogs, and my comments often get deleted. For example, once I tried to put a comment on Archbishop Dolan's blog, correcting some information (about the sexual abuse scandal, if memory serves) by giving a few facts, with links to supporting documents. But my comment never appeared. I was surprised because it expressed no opinion and only stated facts. How can one object to that? That blog sometimes contains criticisms in the comments, so I had not thought that comment moderation was unfair. I spent a few days observing the blog regularly after that, and now have a conjecture: the moderator lets through a balance of positive and begative comments, but biases them so that the negative comments are emotional rants rather than rational arguments. It gives the illusion of being open-minded while subtly veering readers in a certain direction. If my theory is true, that's a pretty sneaky manipulation!
Another time, on a similar site, I tried to post a comment. I knew the moderator was ruthless in deleting whatever he didn't like, so I tried to game the system by posting a quote from his own writing, carefully chosen so that in the context of his post it would be a subtle rebuttal of his rant. I figured that he surely would feel guilty about deleting that post, and was hoping to pass his filter successfully because of that. I naively thought I was being clever. What happened next was impressive: my comment got marked as "waiting to be moderated" before appearing... but half a day later. So, yes, it did appear. But by that time, many readers had moved on to some other topic. Additionally, it appeared at the place in the list of comments where I had originally posted it, so it was buried deep underneath all the comments that appeared in the intervening twelve hours, and so I expect that no one read it. Clever! He outwitted me.
So, the main purpose of moderation is propaganda: then moderation is most effective if it does not consist in stupidly deleting everything that does not fit the moderator's agenda, but in letting some carefully filtered, well-chosen criticism go through.
I have lost a lot of my excitement about blogs as measuring the pulse of public opinion, when I realized that comments do not express the vox populi but the moderator's portrayal of the vox populi. It's a sham.
One burning question: how to test such theories? I would love to see some formal study of blog moderation, preferably extended to information control in general. How can the user figure out whether a blog is biased, and how badly? In both of the above examples, I realized it by mere chance, and I did not repeat the experiment. What about blogs that claim to follow certain rules for moderation: how can we verify that they follow the stated rules, when we do not get to see the deleted comments?
Saturday, May 28, 2011
Foo and toto
I have always taught my students that "toto" was the French equivalent of "foo" for naming a file or a variable when you don't want to be bothered coming up with a name. Although true in practice, in reality the two words have very different origins.
"foo" is supposedly a misspelling of "f.u.", an acronym for "fucked up" as comes up in the military slang term "s.n.a.f.u." or "f.u.b.a.r.", "situation normal, all fucked up" and "fucked up beyond all repair".
"toto" has a less controversial etymology. It comes from the name of a young boy, the main character in a 19th century play. Nowadays Toto usually appears in childish jokes. It is roughly analogous to "Johnny". When I was 6 or 7 years old my friends and I at school exchanged many jokes about Toto, usually involving pee and poop.
On the other hand, another possible origin of "foo", also from WW2, is that apparently, wherever British troops went, the graffito “FOO was here” frequently showed up. I tend to believe that simply because in that case "foo" and "toto" would have more similar origins.
What is used in other languages? The automatic translation tools don't work for foo!
"foo" is supposedly a misspelling of "f.u.", an acronym for "fucked up" as comes up in the military slang term "s.n.a.f.u." or "f.u.b.a.r.", "situation normal, all fucked up" and "fucked up beyond all repair".
"toto" has a less controversial etymology. It comes from the name of a young boy, the main character in a 19th century play. Nowadays Toto usually appears in childish jokes. It is roughly analogous to "Johnny". When I was 6 or 7 years old my friends and I at school exchanged many jokes about Toto, usually involving pee and poop.
On the other hand, another possible origin of "foo", also from WW2, is that apparently, wherever British troops went, the graffito “FOO was here” frequently showed up. I tend to believe that simply because in that case "foo" and "toto" would have more similar origins.
What is used in other languages? The automatic translation tools don't work for foo!
Friday, May 27, 2011
Cars, buses, and generosity
I had a crazy afternoon mismanaging the sharing of my car with various people. At one point, the car was parked in Providence, I was planning to take the bus to go and get it, then realized that I had left my wallet inside it. I quickly gathered a few coins lying around to pay for the bus fare. As I accidentally took an old 1 French Franc coin instead of US money, I ended up being one quarter short, but the driver was kind enough to let me on the bus anyway.
Then my son called, his friends and he urgently needed their school bags, in the trunk of said car. I told my son to take the bus with me to go and pick it up, but he was just a smidge too late for the bus, and his friend's mom ended up chasing it to the next stop, where I pulled the chord for the bus to stop, and asked the driver to wait while my son got out of the friend's mom's car and ran to the bus door. But then, he had no money! I told the driver: "He doesn't have any money!". The driver stayed silent, not saying that he could get in, but not closing the door either. My son stood silently just outside the open door, not daring to go in without the means to pay his fare. I stared at him helplessly, not knowing what to do. Then a passenger broke the spell and told the driver: "Let him in. I'll pay," got a bill out and paid the fare while my son got on. I could hardly believe it!
Without his help, maybe the bus driver would have closed the door and left. Maybe my son's friend's mother would have had left already, assuming he was taking the bus. Then he would have been stranded alone by the side of the highway and with no money. How quickly the incident could have gone from embarrassing to worrisome! Sometimes we just need a little bit of help. Bus riders understand that. Many of them know what it's like to have been hit but a sequence of unlucky events. They understand solidarity with stranded strangers.
Then my son called, his friends and he urgently needed their school bags, in the trunk of said car. I told my son to take the bus with me to go and pick it up, but he was just a smidge too late for the bus, and his friend's mom ended up chasing it to the next stop, where I pulled the chord for the bus to stop, and asked the driver to wait while my son got out of the friend's mom's car and ran to the bus door. But then, he had no money! I told the driver: "He doesn't have any money!". The driver stayed silent, not saying that he could get in, but not closing the door either. My son stood silently just outside the open door, not daring to go in without the means to pay his fare. I stared at him helplessly, not knowing what to do. Then a passenger broke the spell and told the driver: "Let him in. I'll pay," got a bill out and paid the fare while my son got on. I could hardly believe it!
Without his help, maybe the bus driver would have closed the door and left. Maybe my son's friend's mother would have had left already, assuming he was taking the bus. Then he would have been stranded alone by the side of the highway and with no money. How quickly the incident could have gone from embarrassing to worrisome! Sometimes we just need a little bit of help. Bus riders understand that. Many of them know what it's like to have been hit but a sequence of unlucky events. They understand solidarity with stranded strangers.
Thursday, May 26, 2011
Fukushima information, if anyone cares
Two months ago I was struck by the Fukushima disaster and posted a couple of comments about it. Here is updated information in case anyone is interested in what is happening at Fukushima. I am not sure anyone cares anymore: I don't see much about it in the news! Too boring?
Here's a website with all sorts of raw data: here (there is a menu to pick the language, and English is an option). No data for reactor 4, I guess because TEPCO has not yet been able to send people or robots in to restart measurements.
A quick look on reactors 1,2 and 3 indicates, not that the situation is particularly improving, but that many indicators are stationary. There are still ongoing radioactive leaks. Reactor 1 has something going on: at the end of last week the level of radioactivity inside the drywell suddenly increased by a factor of 5, and has been at that higher level since then; but there is a note on the graph saying "instrument failure", so nothing to worry about...
In general, according to this (H/T to Olivier Devillers for telling me about Sylvestre Huet's blog), the situation is "stabilized" in the sense that the injection of water at the rate of a few cubic yards per hour is sufficient to prevent the core temperature from increasing again.
UPDATE 6/2/2011: blog by a Japanese about Fukushima; recommended news web site about Fukushima.
Here's a website with all sorts of raw data: here (there is a menu to pick the language, and English is an option). No data for reactor 4, I guess because TEPCO has not yet been able to send people or robots in to restart measurements.
A quick look on reactors 1,2 and 3 indicates, not that the situation is particularly improving, but that many indicators are stationary. There are still ongoing radioactive leaks. Reactor 1 has something going on: at the end of last week the level of radioactivity inside the drywell suddenly increased by a factor of 5, and has been at that higher level since then; but there is a note on the graph saying "instrument failure", so nothing to worry about...
In general, according to this (H/T to Olivier Devillers for telling me about Sylvestre Huet's blog), the situation is "stabilized" in the sense that the injection of water at the rate of a few cubic yards per hour is sufficient to prevent the core temperature from increasing again.
UPDATE 6/2/2011: blog by a Japanese about Fukushima; recommended news web site about Fukushima.
Tuesday, May 24, 2011
From rural life to city life to virtual life
In the aftermath of the industrial revolution, most of the population shifted from rural life to city life. No more immediate contact with nature all day long, less and less physical work, and more time indoors in an artificial environment with books and machines.
Now the computer revolution is unfolding, and most of the upcoming generation is shifting from city life to virtual life. Time is spent in virtual social networks rather than with neighborhood kids, playing online video games instead of chess and monopoly, reading blogs instead of newspapers, replacing face-to-face sex with online sex, surfing the web instead of chatting with office mates over breaks, texting in church instead of listening to the homily, finding one's way with a GPS instead of by watching the world outside. The virtual world is a great egalitarian. There is neither Jew nor Gentile, neither slave nor free, nor is there male and female. Even in a wheel chair, you can live your virtual life just as well as anyone else. You are free to create your own persona, unlimited by physical constraints.
How can we do better still, and move to a more fully virtual life?
Our bodies are increasingly unnecessary. But we still need to eliminate the remaining burdens of physical reality. When we go to school, eat, sleep, we are not focused on the online world. Here are a few suggestions:
- game developpers should invest heavily in educational games for the classroom setting, so that children are also in the virtual world during school time. This needs to be much more widespread than now so that children learn from an early age that, whenever they are awake, they need to be engaged with a computer screen.
- food is a big time sink. Why do people not buy more ready meals, but still waste time shopping, cooking, eating, and cleaning up? Food processing companies need to greatly improve their products so that people finally give in. At the same time, farms need to grow less tasty food to diminish the contrast in taste between home cooking and fully processed meals. Progress is being made, but the freedom from food is still a long way off.
- sleep is also a huge time sink, although people now sleep about an hour less per night than thirty years ago. Pharmaceutical companies need to continue investing money on drugs that fight drowsiness.
- the keyboard, mouse and pen are discriminatory against those people who are handicapped, not just in the legs, but also in the arms. In addition using hands and fingers to type and click needlessly uses up muscles and physical energy. So, language recognition needs to be greatly perfected so that we can communicate merely by talking, without otherwise moving. In the longer term, research needs to continue actively on automatic interpretation of signals from the brain, so that eventually we can communicate directly with the computer.
- research on robotics needs to accelerate so that robots take over doing all the tasks of daily life that entail any physical effort.
At that point, we will have succeeded in making the physical world irrelevant, and we will be able to spend our time in a world of our own making, the perfect virtual world, where anything is possible if that is our wish. Oh, what a wonderful vision!
Now the computer revolution is unfolding, and most of the upcoming generation is shifting from city life to virtual life. Time is spent in virtual social networks rather than with neighborhood kids, playing online video games instead of chess and monopoly, reading blogs instead of newspapers, replacing face-to-face sex with online sex, surfing the web instead of chatting with office mates over breaks, texting in church instead of listening to the homily, finding one's way with a GPS instead of by watching the world outside. The virtual world is a great egalitarian. There is neither Jew nor Gentile, neither slave nor free, nor is there male and female. Even in a wheel chair, you can live your virtual life just as well as anyone else. You are free to create your own persona, unlimited by physical constraints.
How can we do better still, and move to a more fully virtual life?
Our bodies are increasingly unnecessary. But we still need to eliminate the remaining burdens of physical reality. When we go to school, eat, sleep, we are not focused on the online world. Here are a few suggestions:
- game developpers should invest heavily in educational games for the classroom setting, so that children are also in the virtual world during school time. This needs to be much more widespread than now so that children learn from an early age that, whenever they are awake, they need to be engaged with a computer screen.
- food is a big time sink. Why do people not buy more ready meals, but still waste time shopping, cooking, eating, and cleaning up? Food processing companies need to greatly improve their products so that people finally give in. At the same time, farms need to grow less tasty food to diminish the contrast in taste between home cooking and fully processed meals. Progress is being made, but the freedom from food is still a long way off.
- sleep is also a huge time sink, although people now sleep about an hour less per night than thirty years ago. Pharmaceutical companies need to continue investing money on drugs that fight drowsiness.
- the keyboard, mouse and pen are discriminatory against those people who are handicapped, not just in the legs, but also in the arms. In addition using hands and fingers to type and click needlessly uses up muscles and physical energy. So, language recognition needs to be greatly perfected so that we can communicate merely by talking, without otherwise moving. In the longer term, research needs to continue actively on automatic interpretation of signals from the brain, so that eventually we can communicate directly with the computer.
- research on robotics needs to accelerate so that robots take over doing all the tasks of daily life that entail any physical effort.
At that point, we will have succeeded in making the physical world irrelevant, and we will be able to spend our time in a world of our own making, the perfect virtual world, where anything is possible if that is our wish. Oh, what a wonderful vision!
Saturday, May 21, 2011
Editor at the Ministry of Truth
One danger of articles consulted online rather than printed or downloaded: online articles can change their stories over time, and those updates can help the present control the past, or at least, control the report of the past. That can be used to correct errors, but also to surrepticiously modify undesirable information.
I corrected an example in my post about Markov's inequality, after a comment pointed out that it was wrong in one interpretation. Added a comment, but whoever reads the post but not the comments will never know. (I could also have deleted the comments to erase the past completely!) No big deal for scientific text, but more dicey for journalists writing about political events in online newspapers.
One partial solution: show your work by displaying text that has been modified. I just did that for the blog post on Israel and France sister countries, using strikeout text. I am rather pleased with the result: the factual error is corrected, but the previous version is still visible. I think that it is better than deletion and disappearance.
Should journalists do that when they modify an article after it's been published online?
How about moderators of popular blogs, should they do that? Rather than delete comments that they don't like, leave them in but strike them out? That would make their bias or objectivity evident, and thus make them accountable to the readers.
I corrected an example in my post about Markov's inequality, after a comment pointed out that it was wrong in one interpretation. Added a comment, but whoever reads the post but not the comments will never know. (I could also have deleted the comments to erase the past completely!) No big deal for scientific text, but more dicey for journalists writing about political events in online newspapers.
One partial solution: show your work by displaying text that has been modified. I just did that for the blog post on Israel and France sister countries, using strikeout text. I am rather pleased with the result: the factual error is corrected, but the previous version is still visible. I think that it is better than deletion and disappearance.
Should journalists do that when they modify an article after it's been published online?
How about moderators of popular blogs, should they do that? Rather than delete comments that they don't like, leave them in but strike them out? That would make their bias or objectivity evident, and thus make them accountable to the readers.
Friday, May 20, 2011
How could I live without the internet?
Everyone in my family, including myself, is addicted to the internet. We now have one laptop per person, so that we can spend "together" time, each with his or her own screen. Everywhere I hear reports or remarks about overwhelming screen time.
Imagine I tried to make my home internet-free. Could we survive without the internet evenings and weekends?
It's hard to imagine. Dinner recipes? I would need to get my cookbooks out. Music, movies? I would need to plan in advance what I want to hear or watch. Transportation? I would need to keep my bus schedule accessible. What about arranging for travels, train, flying, hotel reservation etc.? That would have to be done at work, it seems. Friends? Without facebook, some of us would be out of the loop, or we'd have to make plans in advance. Plumber, electrician, garagist? We would need to resurrect the old fashioned yellow pages. Running errands? A combination of yellow pages and phone. Paying bills? Either do it at work, or resurrect the old fashioned checks, envelopes and stamps. Trying to revert to an internet-free environment would require quite a lot of organization!
What would be the upside? Perhaps our books would stop gathering dust on the bookshelves. Perhaps we'd spend more time in conversation, or exercising, or gardening, or in general doing all the things in which one interacts with the physical world. Not that the internet exactly prevents us from doing all those things, but in reality it's a sink that is revolutionizing the way in which we spend our time.
Imagine I tried to make my home internet-free. Could we survive without the internet evenings and weekends?
It's hard to imagine. Dinner recipes? I would need to get my cookbooks out. Music, movies? I would need to plan in advance what I want to hear or watch. Transportation? I would need to keep my bus schedule accessible. What about arranging for travels, train, flying, hotel reservation etc.? That would have to be done at work, it seems. Friends? Without facebook, some of us would be out of the loop, or we'd have to make plans in advance. Plumber, electrician, garagist? We would need to resurrect the old fashioned yellow pages. Running errands? A combination of yellow pages and phone. Paying bills? Either do it at work, or resurrect the old fashioned checks, envelopes and stamps. Trying to revert to an internet-free environment would require quite a lot of organization!
What would be the upside? Perhaps our books would stop gathering dust on the bookshelves. Perhaps we'd spend more time in conversation, or exercising, or gardening, or in general doing all the things in which one interacts with the physical world. Not that the internet exactly prevents us from doing all those things, but in reality it's a sink that is revolutionizing the way in which we spend our time.
Thursday, May 19, 2011
An interactive lesson plan on Markov's inequality
Teacher: Consider the following situation. Driving to work takes you about 20 minutes on average. Is it possible that, with probability 90%, the commute takes you more than 4 hours?
Students: no
Note: Repeat the question twice, once with "90%" and the other with "9/10th" so that each student hears the wording with which he or she is most comfortable. Possibly add specifics about rush hour, downtown, etc, if you need a story to get students going.
The students offer various reasons, but the teacher does not elaborate on them (to save time).
Teacher: Consider another example. You are investing $1000 in some stocks. Your expected return after one year is 5%. Is it possible that, with probability 90%, after one year you will be a millionaire?
Students: no.
Again the teacher does not elaborate (to save time).
Teacher: Now, the question that is the real topic of this lecture. Consider a random non-negative variable X, and way that it's 5 on average. Is it possible that, with probability 90%, X is larger than one million?
Students: no.
Notes:
- take numbers that are so large that the answer is intuitively obvious. It is that intuitive understanding that will provide students with the wedge to understand the meaning of Markov's inequality.
- stress the question that "is the real topic", so that students who are bored because it's too easy for them so far pay attention. Write it on the board just in case.
- why not start directly with the general question? Con of starting directly: at this stage of the course, most students are not yet comfortable with the abstract notion of "random variable", and the examples serve to ground it in reality, reinforcing the teaching of some previous lecture. Con of starting with an example: students might get distracted by the specifics of the example and find reasons that are irrelevant (bus schedule, say), wasting lecture time. Pro of starting directly: I give them only the relevant information, so they're not going to start talking about the distribution r other externals. The best of both world: by starting with, not one, but two examples, stir students away from irrelevance. They should be as similar as possible regarding the numbers used, but as different as possible regarding the context and distribution. They start seeing what properties the two examples have in common, and that directs their thoughts in the right direction. At the same time, that has the side advantage of teaching them a little bit about problem-solving.
Teacher: Why not?
Note: here, do not intervene and let a free discussion between students shape the answer. First, because this does not require particular skills. If they parsed the question, then the "no" answer should be obvious, and you should quickly hear an answer of the form "Because if X was one million almost all the time, then it would have to be more than 5 on average". "Why?" You ask. Eventually someone says something like: "If X is one million 90% of the time, then on average it's at least 900000".
Teacher: Let's formalize that. If X is one million 9/10th of the time, then what can we say about its mean, call it m?
Students: m is at least (9/10)*1000000
Note: when stating the question, make sure to say "9/10th" rather than "90%", to provide a subconscious hint.
Note: repeat the question several times, switching the terms "mean", "average", and "expectation", to reinforce the recent acquisition of that vocabulary by the students, and so that each hears the term which he or she is most comfortable with.
Teacher: What if X is, not exactly one million, but at least one million?
Students: [after thinking about it for a moment] It doesn't make a difference.
Teacher: Let me give you a counterexample. Say that X is, with probability 90%, one million, and will probability 10%, minus one million. [Write those numbers.] Then [write the one-line calculation] X is 800000 on average, so it's not true that, as you claimed, m is at least 900000.
Students: [after thinking about it for a moment] But X has to be non-negative.
Note: place this question right before the proof, as a reminder of that assumption, so that when they have to use it in the proof, it's fresh in their minds.
Teacher: Now, let's extend the problem. If X is one million (or more than one million) with probability p, then what can we say about m?
Students: m is at least 1000000p.
Teacher: Let's extend it further. If X is at least some threshold value v with probability p, then what can we say about m?
Students: m is at least vp.
Note: introduce variable names one at a time. Most people have trouble with abstraction for new concepts, and that makes it easier for them to not get lost by a sudden jump from concrete numbers to abstract algebraic equations. It helps preserve the link between reality and abstraction.
Teacher: Can you prove it? [Then, if no suggestion comes forth:] Remember the definition of expectation. Let's say, to simplify, that X is an integer random variable, so it only takes on integer values.
Students: E(X) is the sum over i of i times the probability that X equals i.
Teacher: actually, in the case it's more convenient to use another characterization of expectation of integer random variables that we have seen before.
Students (remembering): E(X) is the sum over i of the probability that X is greater than or equal to i.
(after some period of fumbling) Aha! So, we can just look at the terms for i=1,2,...,1000000 (v). Each term is at least p, because, if X is at least one million, then X is at least i. So we get p+p+...p, v times, so it's pv.
Teacher: Great. Where did you use the fact that X was non-negative?
Students: (after a blank moment) oh, right; it's necessary for our characterization of expectation.
Note: serves as a quick reminder to reinforce the assumptions behind that equality.
Teacher: You have proved: m>= vp. That's essentially Markov's inequality, but it's usually used, as in the examples above, to prove for variables where m is known, p is unknown, and we use this to prove bounds on p. Can you restate it in that form?
Students: [hesitate, then someone says:] p <= m/v.
End of interactive part, the teacher takes over and writes the final statement of Markov's inequality and its proof, writing it all on the board while the students take notes.
Extra time: Apply the final statement to the examples from the beginning of class. Give the proof for continuous random variables as well (using integrals), pointing out similarities.
Note: Be ready for a different proof. For example a student might say: "The minimum m could be, given our assumptions, would be if X was 1000000 exactly 90% of the time and was 0 the other 10% of the time, and in that case m would be exactly equal to 900000", and then the proof developped in lecture should be built on that insight.
Note: This takes a lot longer than just giving the statement and proof. But it makes the lecture much more interesting for the teacher because we never know what's going to happen, and for the students because they are developing their own insights --- they can have their "Aha" moments. It's also a great way to gauge their level of understanding (or at least, the level of understanding of those who participate.) Hopefully it will help them better remember Markov's inequality. Recapping in the end by writing the statement and proof in full is boring for those students who were most active in the discussion, but necessary for those who are struggling to follow. It can be done quickly, but it has to be done.
Students: no
Note: Repeat the question twice, once with "90%" and the other with "9/10th" so that each student hears the wording with which he or she is most comfortable. Possibly add specifics about rush hour, downtown, etc, if you need a story to get students going.
The students offer various reasons, but the teacher does not elaborate on them (to save time).
Teacher: Consider another example. You are investing $1000 in some stocks. Your expected return after one year is 5%. Is it possible that, with probability 90%, after one year you will be a millionaire?
Students: no.
Again the teacher does not elaborate (to save time).
Teacher: Now, the question that is the real topic of this lecture. Consider a random non-negative variable X, and way that it's 5 on average. Is it possible that, with probability 90%, X is larger than one million?
Students: no.
Notes:
- take numbers that are so large that the answer is intuitively obvious. It is that intuitive understanding that will provide students with the wedge to understand the meaning of Markov's inequality.
- stress the question that "is the real topic", so that students who are bored because it's too easy for them so far pay attention. Write it on the board just in case.
- why not start directly with the general question? Con of starting directly: at this stage of the course, most students are not yet comfortable with the abstract notion of "random variable", and the examples serve to ground it in reality, reinforcing the teaching of some previous lecture. Con of starting with an example: students might get distracted by the specifics of the example and find reasons that are irrelevant (bus schedule, say), wasting lecture time. Pro of starting directly: I give them only the relevant information, so they're not going to start talking about the distribution r other externals. The best of both world: by starting with, not one, but two examples, stir students away from irrelevance. They should be as similar as possible regarding the numbers used, but as different as possible regarding the context and distribution. They start seeing what properties the two examples have in common, and that directs their thoughts in the right direction. At the same time, that has the side advantage of teaching them a little bit about problem-solving.
Teacher: Why not?
Note: here, do not intervene and let a free discussion between students shape the answer. First, because this does not require particular skills. If they parsed the question, then the "no" answer should be obvious, and you should quickly hear an answer of the form "Because if X was one million almost all the time, then it would have to be more than 5 on average". "Why?" You ask. Eventually someone says something like: "If X is one million 90% of the time, then on average it's at least 900000".
Teacher: Let's formalize that. If X is one million 9/10th of the time, then what can we say about its mean, call it m?
Students: m is at least (9/10)*1000000
Note: when stating the question, make sure to say "9/10th" rather than "90%", to provide a subconscious hint.
Note: repeat the question several times, switching the terms "mean", "average", and "expectation", to reinforce the recent acquisition of that vocabulary by the students, and so that each hears the term which he or she is most comfortable with.
Teacher: What if X is, not exactly one million, but at least one million?
Students: [after thinking about it for a moment] It doesn't make a difference.
Teacher: Let me give you a counterexample. Say that X is, with probability 90%, one million, and will probability 10%, minus one million. [Write those numbers.] Then [write the one-line calculation] X is 800000 on average, so it's not true that, as you claimed, m is at least 900000.
Students: [after thinking about it for a moment] But X has to be non-negative.
Note: place this question right before the proof, as a reminder of that assumption, so that when they have to use it in the proof, it's fresh in their minds.
Teacher: Now, let's extend the problem. If X is one million (or more than one million) with probability p, then what can we say about m?
Students: m is at least 1000000p.
Teacher: Let's extend it further. If X is at least some threshold value v with probability p, then what can we say about m?
Students: m is at least vp.
Note: introduce variable names one at a time. Most people have trouble with abstraction for new concepts, and that makes it easier for them to not get lost by a sudden jump from concrete numbers to abstract algebraic equations. It helps preserve the link between reality and abstraction.
Teacher: Can you prove it? [Then, if no suggestion comes forth:] Remember the definition of expectation. Let's say, to simplify, that X is an integer random variable, so it only takes on integer values.
Students: E(X) is the sum over i of i times the probability that X equals i.
Teacher: actually, in the case it's more convenient to use another characterization of expectation of integer random variables that we have seen before.
Students (remembering): E(X) is the sum over i of the probability that X is greater than or equal to i.
(after some period of fumbling) Aha! So, we can just look at the terms for i=1,2,...,1000000 (v). Each term is at least p, because, if X is at least one million, then X is at least i. So we get p+p+...p, v times, so it's pv.
Teacher: Great. Where did you use the fact that X was non-negative?
Students: (after a blank moment) oh, right; it's necessary for our characterization of expectation.
Note: serves as a quick reminder to reinforce the assumptions behind that equality.
Teacher: You have proved: m>= vp. That's essentially Markov's inequality, but it's usually used, as in the examples above, to prove for variables where m is known, p is unknown, and we use this to prove bounds on p. Can you restate it in that form?
Students: [hesitate, then someone says:] p <= m/v.
End of interactive part, the teacher takes over and writes the final statement of Markov's inequality and its proof, writing it all on the board while the students take notes.
Extra time: Apply the final statement to the examples from the beginning of class. Give the proof for continuous random variables as well (using integrals), pointing out similarities.
Note: Be ready for a different proof. For example a student might say: "The minimum m could be, given our assumptions, would be if X was 1000000 exactly 90% of the time and was 0 the other 10% of the time, and in that case m would be exactly equal to 900000", and then the proof developped in lecture should be built on that insight.
Note: This takes a lot longer than just giving the statement and proof. But it makes the lecture much more interesting for the teacher because we never know what's going to happen, and for the students because they are developing their own insights --- they can have their "Aha" moments. It's also a great way to gauge their level of understanding (or at least, the level of understanding of those who participate.) Hopefully it will help them better remember Markov's inequality. Recapping in the end by writing the statement and proof in full is boring for those students who were most active in the discussion, but necessary for those who are struggling to follow. It can be done quickly, but it has to be done.
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