Fim de ano, passei minhas notas, e olhei umas outras tantas. Quanto mais branca minha barba, menos consigo entender os critérios de notas na Poli. Diria que seguem aproximadamente a seguinte fórmula:
Nota = 3 + 4 (esforço feito pelo aluno) / (esforço esperado pelo professor) + 3 RandomReal[-1,+1]
A prova típica dá 3 pontos por assinar a lista de presença e responder uma questãozinha primária, continua com duas questões que um aluno mais ou menos assíduo deveria saber responder, e termina com uma questão impossível para lembrar que 10 é a nota do professor. O inevitável componente aleatório, mais pronunciado no caso de avaliações ditas "objetivas," sempre pode tomar valores positivos ou negativos.
Isso para graduação. Para pós-graduação os critérios são diferentes: as notas são mais altas, embora não seja claro que os alunos sejam melhor preparados ou que se esforcem mais. E na avaliação dos próprios professores as notas são muito mais altas: só tira menos que 9 num concurso de titular quem comete o gravíssimo erro de não fazer parte da panelinha que escolheu a banca.
Proposta de pesquisa: como os critérios de avaliação afetam os hábitos de um estudante racional? Sabendo que o 3 está garantido pela questão fácil, parece razoável que o aluno que quer minimizar a probabilidade de reprovação estude pouco. E que o aluno que quer maximizar a nota também não estude muito, já que os últimos pontos são inatingíveis. Razoável esse modelo?
(Esse post gerou tantos comentários de visitantes ilustres, que resolvi linkar para um vídeo dando exemplo de prova com 5 perguntas no estilo politécnico, uma trivial, uma fácil, e uma aleatoriamente difícil.)
22 dezembro 2009
21 dezembro 2009
Gastos militares do Brasil
Segundo O Globo, o Brasil gasta 50 mil contos de réis por ano em defesa. Desses $30 bi de dólares, $15 bi vão para aposentadorias e pensões, e mais $9 bi para os soldos. Sobram $4 bi para custeio e $2 bi para investimento - as armas propriamente ditas. Ou seja, o exército é essencialmente uma bolsa-família militar. Em caso de guerra temos que contar para a defesa com a selva amazônica e os sete mares. A aposentadoria dos militares daria para manter 10 universidades como a Usp! Que também gasta em aposentadorias quase o mesmo que paga aos professores ativos, mas essa é outra história - os números oficiais dão uma proporção de 50%, mas uma fração grande dos salários dos professores ativos vai diretamente para sustentar a máquina de pensões do estado. A diferença é que um professor pode contribuir para a educação mesmo com armamento leve. Já um marinheiro sem navio não faz nada pela proteção do país.
20 dezembro 2009
Practical engineers
"The practical engineer, who judges himself quite immune to the need of theoretical novelties, is usually the slave of a defunct mathematician."
19 dezembro 2009
Cop15 as I saw it
Here is a summary of the Copenhagen climate talks as I saw them on the Web 2.0 - a rather partial point of view, but not that much worse than what you'll read on the papers tomorrow.
Katrine Dalsgård together with her husband Thomas Fløe and their son Kristoffer hosted guests from Zambia and the UK. Through an organization called New Life Copenhagen, Danes showed their world-leading hospitality by hosting thousands of international attendants to the summit. Links in English (video), French (video), and Danish (text, subscription required).
José Serra seems to have enjoyed himself in the cold weather, especially working with fellow governor Schwarzenegger. He gave the impression that he had productive conversations with various international and domestic players, that he made constructive proposals, and that he bought the ideas of Green Party candidate Marina Silva completely. Whether true or just vaguely so, this impression may come in handy in the 2nd round of the Brazilian presidential elections next year. Prime Minister Gordon Brown and the two governors seemed to be among the few trying to get some work done, apart from the thousands of Danish citizens who like the Dalsgård-Fløes opened their homes to visitors from around the world.
Dilma Roussef, the Worker's Party presidential candidate, had a Freudian slip: "The environment is a threat to sustainable development." May not be what she meant to say but pretty much sums up her environmental record. Subsequently she and Lula contradicted each other on a number of important points. Whether either had much of a clue about what they were saying is a matter of conjecture.
President Obama showed up in the last minute - he seems to be enjoying these short visits to Scandinavia - and burst into a meeting between Lula, Manmohan Singh, and the current Chinese dictator, who were privately plotting to block any deal. In all fairness to the Prime Minister, of all the main players in the climate change - China, the US, Europe, Russia, Brazil, and Indonesia - India has least to contribute. It is much poorer than all but Indonesia so it has less to spend, and emits a lot less per person than any of these countries so it has less to cut. In any case Obama seems to have wrestled some type of agreement, perhaps a disappointing one, out of countries that came ready to avoid any progress. He also crammed in a chat with Medvedev about nuclear weapons, pretty much the only subject on which anyone will listen to Russia.
Predictions for tomorrow and the next few days: the right will continue to deny that humans are causing global warming, the same way that they deny a large fraction of modern science - the names of Darwin and Keynes come to mind. They will also deny that the climate is changing at all, that the changes can be dangerous, and that they it may be worthwhile to avoid them. But in any case they will blame Obama and the socialist Europeans for whatever they will say went wrong.
The left will blame the Danes for the lack of a deal and the Jews for global warming - keep an eye on the usual suspects. African and Latin American politicians will congratulate themselves on standing up to the Americans, and will say that failure to achieve a deal which they never wanted is good because it allows the economic development of poor countries by any means necessary - and at whatever cost to their own people, the poor especially, but that is another story. In that sense the left-wing position is similar to the right-wing one, with a relevant difference: while the right is proud of not reading Keynes or Darwin or the IPCC reports, the left claims to have read and follow all of them - although without understanding what the science means.
Oh and before I forget some self-appointed very smart people will act superior and befuddled - the Economist has already made comments relating the climate talks to Niels Bohr's Copenhagen interpretation of quantum mechanics. Prediction for the next decade: warm, with a chance of hurricanes.
Katrine Dalsgård together with her husband Thomas Fløe and their son Kristoffer hosted guests from Zambia and the UK. Through an organization called New Life Copenhagen, Danes showed their world-leading hospitality by hosting thousands of international attendants to the summit. Links in English (video), French (video), and Danish (text, subscription required).
José Serra seems to have enjoyed himself in the cold weather, especially working with fellow governor Schwarzenegger. He gave the impression that he had productive conversations with various international and domestic players, that he made constructive proposals, and that he bought the ideas of Green Party candidate Marina Silva completely. Whether true or just vaguely so, this impression may come in handy in the 2nd round of the Brazilian presidential elections next year. Prime Minister Gordon Brown and the two governors seemed to be among the few trying to get some work done, apart from the thousands of Danish citizens who like the Dalsgård-Fløes opened their homes to visitors from around the world.
Dilma Roussef, the Worker's Party presidential candidate, had a Freudian slip: "The environment is a threat to sustainable development." May not be what she meant to say but pretty much sums up her environmental record. Subsequently she and Lula contradicted each other on a number of important points. Whether either had much of a clue about what they were saying is a matter of conjecture.
President Obama showed up in the last minute - he seems to be enjoying these short visits to Scandinavia - and burst into a meeting between Lula, Manmohan Singh, and the current Chinese dictator, who were privately plotting to block any deal. In all fairness to the Prime Minister, of all the main players in the climate change - China, the US, Europe, Russia, Brazil, and Indonesia - India has least to contribute. It is much poorer than all but Indonesia so it has less to spend, and emits a lot less per person than any of these countries so it has less to cut. In any case Obama seems to have wrestled some type of agreement, perhaps a disappointing one, out of countries that came ready to avoid any progress. He also crammed in a chat with Medvedev about nuclear weapons, pretty much the only subject on which anyone will listen to Russia.
Predictions for tomorrow and the next few days: the right will continue to deny that humans are causing global warming, the same way that they deny a large fraction of modern science - the names of Darwin and Keynes come to mind. They will also deny that the climate is changing at all, that the changes can be dangerous, and that they it may be worthwhile to avoid them. But in any case they will blame Obama and the socialist Europeans for whatever they will say went wrong.
The left will blame the Danes for the lack of a deal and the Jews for global warming - keep an eye on the usual suspects. African and Latin American politicians will congratulate themselves on standing up to the Americans, and will say that failure to achieve a deal which they never wanted is good because it allows the economic development of poor countries by any means necessary - and at whatever cost to their own people, the poor especially, but that is another story. In that sense the left-wing position is similar to the right-wing one, with a relevant difference: while the right is proud of not reading Keynes or Darwin or the IPCC reports, the left claims to have read and follow all of them - although without understanding what the science means.
Oh and before I forget some self-appointed very smart people will act superior and befuddled - the Economist has already made comments relating the climate talks to Niels Bohr's Copenhagen interpretation of quantum mechanics. Prediction for the next decade: warm, with a chance of hurricanes.
16 dezembro 2009
Dirceu apoiando a ditadura
Não vou deixar de comentar o artigo do ex-ministro-chefe do Couto e Silva, o Comandante José Dirceu, defendendo a recepção oficial de seu governo ao ditador da Pérsia. Por conta do apoio russo ao golpe de estado de Ahmadinejad, o povo grita "Morte à Rússia" nas passeatas pela democracia em Teerã. Temos sorte que os estudantes persas sabem diferenciar entre o pacífico povo brasileiro e nosso governo tiranófilo, senão o entusiasmo do Itamaraty pela repressão policial já estaria rendendo gritos de marg-bar-Barazil. Vale a pena notar o argumento do ministro em favor da sangrenta ditadura militar-teocrática: mudar de assunto e culpar Israel. Um pouco mais original é o apoio ao genocida Slobodan Milosevic, que fica implícito no raciocínio do ex-ministro quando culpa a guerra civil na Iugoslávia no imperialismo americano (está em um dos últimos parágrafos). O quê causa o quê na mente do ex-ministro: o amor aos ditadores de extrema-direita de como Ahmadinejad e de extrema-esquerda como Slobodan; a vontade de registrar uma posição diferente das de democratas como Fernando Henrique e de Barack Obama; ou o anti-semitismo?
Lunatics of the world, unite!
A colleague wrote to our class list Poel85 that he's never been very much into communicating via blogs. I can think of a good reason: blog readers, with the exception of people who comment on this blog, are a bunch of lunatics! There also exist complete idiots, but the majority of idiots who make comments are lunatics as well.
Every incident in the world that involves a Moslem or an Arab brings about a series of accusations that "all Arabs are such-and-such and unless you agree with me you are also," and the equally reasoned counter-accusation that "if you think that Moslems are then you must be a..." I'll leave aside any international incident that involves Israel, as well as the majority of incidents that don't even involve Israel, but still serve as an excuse to start an anti-Semitic diatribe. Or think of all the amazing theories that get repeated in economics blogs: Are there really so many people who think Paul Krugman is a fascist-communist? Some bloggers such as Gustavo Chacra go to the trouble of gently answering their followers, probably after erasing the most offensive posts: others poke fun at the most ridiculous comments like Alexandre Schwartsman. Still the lunatics keep coming back.
One thing is certain: the lunatics seems to take extremist positions, in the common ground beyond the extreme left and the extreme right. There seem to be fewer of them talking about the natural sciences - very few scientists can be found among climate change deniers, or among the people who believe that gravitation is untrue because Einstein was a Jew.
But the questions are: How many lunatics are there in the world? How do they find the time to write? Where were they before the internet? Are there more of them now, or are they more visible? Are there many such lunatics still hiding behind a façade of politeness? Can we classify the diplomatic left-wing supporters of the the Axis among them?
Every incident in the world that involves a Moslem or an Arab brings about a series of accusations that "all Arabs are such-and-such and unless you agree with me you are also," and the equally reasoned counter-accusation that "if you think that Moslems are then you must be a..." I'll leave aside any international incident that involves Israel, as well as the majority of incidents that don't even involve Israel, but still serve as an excuse to start an anti-Semitic diatribe. Or think of all the amazing theories that get repeated in economics blogs: Are there really so many people who think Paul Krugman is a fascist-communist? Some bloggers such as Gustavo Chacra go to the trouble of gently answering their followers, probably after erasing the most offensive posts: others poke fun at the most ridiculous comments like Alexandre Schwartsman. Still the lunatics keep coming back.
One thing is certain: the lunatics seems to take extremist positions, in the common ground beyond the extreme left and the extreme right. There seem to be fewer of them talking about the natural sciences - very few scientists can be found among climate change deniers, or among the people who believe that gravitation is untrue because Einstein was a Jew.
But the questions are: How many lunatics are there in the world? How do they find the time to write? Where were they before the internet? Are there more of them now, or are they more visible? Are there many such lunatics still hiding behind a façade of politeness? Can we classify the diplomatic left-wing supporters of the the Axis among them?
14 dezembro 2009
Se alguém perdeu as últimas do Itamaraty...
A Folha registrou e comentou as últimas declarações de simpatia ao Eixo feitas pelos malucos do Itamaraty. Tenho que dar o braço a torcer para os comentaristas desse blog: de fato comparado com seu cunhado Samuel Pinheiro Guimarães, o embaixador Celso Amorim é um sujeito ponderado. Nem o Marco Aurélio Garcia dos gestos obscenos foi pego registrando suas simpatias nazi-fascistas em público.
12 dezembro 2009
Dengue na Usp
Trechos de email da Cocesp - só o nome desse órgão já é coisa do país da piada pronta! "Notícia boa: Foi encontrada uma larva do Aedes aegypti na área da COCESP. Notícia preocupante: Algumas equipes ainda não retiraram suas indispensáveis camisetas." Realmente não vou dormir essa noite...... de preocupação..... ou por causa dos mosquitos?
11 dezembro 2009
Tá na hora de pôr algo polêmico.....
.... para não perder os poucos leitores que esse blog pode ainda ter. Keywords polêmicos chamam atenção do Google :-) Então vai lá: essa decisão do Supremo de não fazer nada a respeito da censura ao Estadão..... foi uma merda. Uma burocrática tecnicista corporativista pusilânime.... merda.
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