Why are there no providers that give unlimited cellphone usage for a flat fee. There is even such a thing for data on a cell phone. Could it be b/c the business is in people going over their minutes? Or because the bandwidth costs would be too high if people used their phone too much.
More interesting question: how much bandwidth does a cell-to-cell conversation take?
Probably more important is that a given network probably charges all other networks to deliver data within itself. ie verizon charges tmobile in order to make a call from a tmobile phone to a verizon one. I wonder if flat-fee unlimited is doable, though...
I think such a provider would make a killing in its first few months of appearance and then the rest of the providers would need to catch up.
Tuesday, October 31, 2006
Sunday, October 15, 2006
WTC simple experiment
- collect videos and calculate an average (over the different clips) time t0 of fall of the buildings
- calculate t from y = 0.5gt^2 (y is height of bldng)
- compare those two numbers, the 2nd places a lower bound on the time of fall.
How close does that make the 2nd number to the average obtained from the clips? If the buildings were not demolished expect that the lower bound is not tight at all ie t0 > t. It'd also be relevant to estimate a correction for free fall with air resitance to obtain a tighter bound, though this may be too tricky
- calculate t from y = 0.5gt^2 (y is height of bldng)
- compare those two numbers, the 2nd places a lower bound on the time of fall.
How close does that make the 2nd number to the average obtained from the clips? If the buildings were not demolished expect that the lower bound is not tight at all ie t0 > t. It'd also be relevant to estimate a correction for free fall with air resitance to obtain a tighter bound, though this may be too tricky
Saturday, October 14, 2006
How I'd teach a class
Lecture
- Make all lecture notes available and discourage note-taking in class
- Have lecture twice a week on UH + an informal optional session (Imamura's E&M stlye)
- Treat lecture like a discussion section during which the formalism is developed by the class. That is, I'm merely leading in the sense of determinig what should be done next, not the usual instructor talks and writes derivations on the chalkboard.
- Make clear what to read before each lecture (kinda like English classes are treated). Encourage coming with questions.
- 5 minute quiz at the beginning of each or every other lecture (to get feedback)
HW
Assign 4 problems every H due following U. Assign 2 problems every U due following H. The idea: to be thinking about subject constantly.
Assigning Grades
Give choice on grading schemes to be picked from individually by each person. Possible grading components:
- HW
- in class midterm
- traditional final (ie as scheduled by registrar)
- take home midterm/final
- Steck style midterm/final (late in the day with "unlimited" time, but to be done in one sitting, possibly 1 open book + notes or something similar)
- final project/paper
People get to mix, match and weigh each grading component as they wish before the fact. Say grading schemes should be picked by week 2 (after they've gotten a chance to see how HW is going to be). This doesn't necessarily guarantee fairness in grading across the board, but it allows for people to be graded in terms of how each performs better. The assumption, of course is that students actually care and aren't just trying to get a grade out of the class.
Book
Require one main (possibly expensive) text book (e.g. Sakurai in QM) and several cheap supplementary books (e.g. Dover QM books) and provide as many free resources as possible (ie free lecture notes, free online books, class reserves, books to be borrowed from me, etc).
Feedback
If I assign a problem it means that I'm willing to do it also and that I'm willing to provide feedback on solutions for people who want it (ie turn in your problems if you want feedback regardless of whether or not you want them graded). Stick to Peter Dolan's philosophy on willingness to look over people's work.
RFC! Constantly request feedback, in written form and with option to remain anonymous. Internet should come in handy for this.
----
In between the reading and the problems each week this would make for a pretty time consuming class. The assumption is that people are interested enoguh to work beyond what the university formally defines as credit. I'd make this expectation clear on day 1. If anyone has problem with it, I treat class as regular class for this person ie I pick grading scheme so that only midterm/final determine grade.
- Make all lecture notes available and discourage note-taking in class
- Have lecture twice a week on UH + an informal optional session (Imamura's E&M stlye)
- Treat lecture like a discussion section during which the formalism is developed by the class. That is, I'm merely leading in the sense of determinig what should be done next, not the usual instructor talks and writes derivations on the chalkboard.
- Make clear what to read before each lecture (kinda like English classes are treated). Encourage coming with questions.
- 5 minute quiz at the beginning of each or every other lecture (to get feedback)
HW
Assign 4 problems every H due following U. Assign 2 problems every U due following H. The idea: to be thinking about subject constantly.
Assigning Grades
Give choice on grading schemes to be picked from individually by each person. Possible grading components:
- HW
- in class midterm
- traditional final (ie as scheduled by registrar)
- take home midterm/final
- Steck style midterm/final (late in the day with "unlimited" time, but to be done in one sitting, possibly 1 open book + notes or something similar)
- final project/paper
People get to mix, match and weigh each grading component as they wish before the fact. Say grading schemes should be picked by week 2 (after they've gotten a chance to see how HW is going to be). This doesn't necessarily guarantee fairness in grading across the board, but it allows for people to be graded in terms of how each performs better. The assumption, of course is that students actually care and aren't just trying to get a grade out of the class.
Book
Require one main (possibly expensive) text book (e.g. Sakurai in QM) and several cheap supplementary books (e.g. Dover QM books) and provide as many free resources as possible (ie free lecture notes, free online books, class reserves, books to be borrowed from me, etc).
Feedback
If I assign a problem it means that I'm willing to do it also and that I'm willing to provide feedback on solutions for people who want it (ie turn in your problems if you want feedback regardless of whether or not you want them graded). Stick to Peter Dolan's philosophy on willingness to look over people's work.
RFC! Constantly request feedback, in written form and with option to remain anonymous. Internet should come in handy for this.
----
In between the reading and the problems each week this would make for a pretty time consuming class. The assumption is that people are interested enoguh to work beyond what the university formally defines as credit. I'd make this expectation clear on day 1. If anyone has problem with it, I treat class as regular class for this person ie I pick grading scheme so that only midterm/final determine grade.
Thursday, October 12, 2006
Hydrogen-like Energy Spectrum
No need to fully separate variables to obtain the energy spectrum from radial wave fxns! Use the variational principle instead. For a suitable wavefxn guess the exact answer may come up anyways.
The minimization can be done numerically. The trial wave functions can have several free parameters.
The minimization can be done numerically. The trial wave functions can have several free parameters.
Stat Mech
- Read Chandler cp. 1 & 2
- Read Landau-Lifshitz cp. 1 & 2
Things to do:
- Prove Lioville's thm
- Derive canonical ensemble from microcanonical
- Derive Maxwell velocity distribution
- Work out Gaussian integrals in general AND memorize results
- Go over notes from reading Phillies cps 1-4.
- Get to the bottom of S = <ρ> =? Sum[ρ log ρ]
- Read Landau-Lifshitz cp. 1 & 2
Things to do:
- Prove Lioville's thm
- Derive canonical ensemble from microcanonical
- Derive Maxwell velocity distribution
- Work out Gaussian integrals in general AND memorize results
- Go over notes from reading Phillies cps 1-4.
- Get to the bottom of S = <ρ> =? Sum[ρ log ρ]
Monday, October 09, 2006
WTF?
You are not supposed to understand what gets written here. I'm just using this as a way to keep track of thoughts I don't want to forget. However, if you see any benefit in reading my thinking out loud... feel free!
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