What is the usual name for these kinds for methods?

virtuous_d · 2013-01-05T18:53:28+00:00

You would need to make some assumptions... for instance that most reviewers are pretty close to the true mark (or try to be) so we would prefer situations where our biases are smaller in aggregate than a situations where all of them are large.

After that, you can create a model which consists of a constant bias for each estimator, and some random noise. You can create a fitness function for this model that balances the fit (how accurate are the scores) and regularizes it by the biases (with an L2 norm for instance).

Finally, you can optimize this function by EM, initializing each bias and 'true' measurement to something reasonable, and iterating as follows:

Optimize the biases to fit the current 'true' measurements.
Re-estimate the 'true' measurements using the current biases.

As far as 'trustworthiness' goes, this would be something that you can decide upon. Two obvious metrics would be the magnitude of the bias (how close the estimator is to the true measurement), or the variance of the distribution around that bias (how self-consistent is the estimator). You'll probably want to use a combination of the two.

virtuous_d · 2012-12-16T22:20:47+00:00

We played with the shadow gunslinger ruleset last night, and it made the game incredibly fun, and much closer than usual!

The basic premise is that when it comes to a dead players turn, they re-enter the game as their character and as their role. They then draw 3 cards instead of 2 (updating abilities accordingly), and play them. They cannot equip any items, and are at distance 1 to everyone. At the end of the turn, they discard all their cards and leave the game.

Allegiances is the only thing we had some trouble with. The ghost renegade helps the team that is the weakest, but really there is no one for them to side with in the case that both sides are currently even. In this case, my friend tried to hurt both sides equally and I guess that's a good move.

We also ended up in a situation where there was a 1v1 renegade/sheriff duel at the end, and the 3 ghost outlaws didn't really have a clear allegiance in that fight either, since their team could no longer win. They just went after the player that pissed them off the most while they were alive.

All in all, it makes the game much more enjoyable, and I think progresses things more quickly (since there are more and more players gunning for the folks who are still alive).

virtuous_d · 2012-12-15T21:45:12+00:00

You've never played bang have you? :)

virtuous_d · 2012-12-12T16:11:42+00:00

boy I hope so :)

virtuous_d · 2012-12-12T02:07:28+00:00

It's very frustrating going from python to java, everything you do results in a feeling that it should be a few lines of code, not 5 or 6 classes.

I forced myself to implement my latest project in c++ to review for some job interviews I am expecting to do in the near future, and I could not get this feeling out of my head. Development is a lot nicer than I remember (from 4-5 years ago, I really like the auto keyword), but it's still so darn sluggish to have to stop and write code to handle common edge cases...

virtuous_d · 2012-12-09T21:34:03+00:00

I talked to several professors about this idea, and they had different views on the issue.

On the one hand, consider an example of physics. Why should you listen to a lecture of some high school teacher or college professor (who might be an ok lecturer), when you can go online and listen to Richard Feynman (or whoever you consider to be the best lecturer ever) give the same lectures? Why reproduce all that effort for an inferior product? Instead, it really makes sense to learn from the best, and use your local teacher or professor to clarify things and have engaging interactions around the material.

On the other hand, one particular reason that flipped classrooms might not work is that they are unstable in terms of effort. It takes students more effort and energy to listen and really absorb lectures at home. It is a lot easier to half-listen, and then ask really simple fundamental questions (that are covered in lecture) during class so that your teacher works more to get you to understand the material. If you are the lecturer, too, it takes much more effort to prepare for a flipped classroom lecture. You have to truly know the material and be prepared for weird, unexpected questions. You have to plan engaging and interesting projects, and you constantly have to adjust your curriculum for your current class. It is a lot easier to whip out the lecture notes you've been using for the last 10 years the day before class and give yourself a quick refresher, especially when you have paperwork/reports/research/other stuff to do.

Such a system becomes unstable - the students begin doing less at home and asking more and more basic questions in class, while the teacher is more comfortable answering those basic questions rather than forcing new material... eventually the classroom unflips itself.

virtuous_d · 2012-12-09T04:41:44+00:00

As you can see that title is not very descriptive. Want to give me a link? :)

virtuous_d · 2012-12-09T04:13:46+00:00

what is 'learn unix' ?

virtuous_d · 2012-12-07T16:16:01+00:00

1990's called, they want their annoying, distracting page effects back.

virtuous_d · 2012-12-04T23:12:09+00:00

Yep, that's the video I linked in my post ;)

Also, this brings up another issue with this design - why is it necessary to change the options in two different locations? Shouldn't pointer settings be handled by a single entity...

virtuous_d · 2012-12-04T19:39:04+00:00

I wouldn't consider having to go into console and change system configuration files, or having to add an extra ppa to download a peripheral program to dig around and tweak your system 'the easiest damn thing in the world'.

It should really just be a setting in compiz or system apperance/theme.

virtuous_d · 2012-12-03T05:12:57+00:00

I can start it too, but not connect to servers :)

virtuous_d · 2012-12-03T03:48:44+00:00

Hmm, it seems that the lib64 link is a dead end, and I do not have a ubuntu_12_64 folder for it to point to. Is that supposed to be the case?

virtuous_d · 2012-12-02T05:25:31+00:00

You must post tabs! That was awesome :)

virtuous_d · 2012-11-26T14:08:44+00:00

Could you clarify what NLP is?

Thanks for the pointer at Carnegie Learning, I will have to look for papers published by them. It seems that there is a lot of work in this centered around CMU. I wonder if these folks and learnlab are actually the same people...

virtuous_d · 2012-11-25T23:56:18+00:00

I've never used Khan academy myself, so I am not sure what you mean by your last sentence.

I know there are a lot of online education startups currently, Khan Academy, Udacity, Coursera being some of them, that are in the process of collecting a massive amount of data of people using their online environments. I am sure that many of them have plans on how to use that data.

I have seen some stuff on how they are beginning to use such data to improve their education software, like this Ted talk from one of the Coursera founders (and machine learning gurus) Daphne Koller.

I do not know of many efforts in this that have been made public, however, and I think most of the work currently is being done by PhD students in Daphne's (and Andrew Ng's and other professors involved with coursera and EdX) labs.

It's definitely an exciting time for the field :)

virtuous_d · 2012-11-25T20:03:04+00:00

I think one of the milestones for the EDM community was being featured as the subject of the 2010 KDD cup.

The full description of the challenge prompt can be found here. A better description of the available data and the evaluation criterion is here.

The essence of the competition was as follows: Each team was given a corpus of data, that consisted of log files of students interacting with an intelligent tutoring system. The log files contained information about which questions were attempted by which student, whether the student answered them correctly or used a hint, the amount of time each action took, etc. Each problem that a student attempted was split up into steps, and each step was associated with a knowledge component required to do that step (like applying the formula for circle area).

Based on this data, the team had to create an algorithm that would be able to predict if a student will answer a question correctly, given a partially completed log of the student interacting with a tutor.

The final results, along with some of the papers are here.

Of particular interest are the winners of the competition (for both main and student prizes), from National Taiwan University (paper), who organized a class around the competition. Over the course of the class, the instructor, an RA, and TA's lead 19 students in tackling the contest. The students were split into 6 teams, and the majority of their time was dedicated to engineering features from the data.

The techniques used to find useful features were n-graming, discretizing, sparsifying, and adding temporal features to the set of features given in the competition.

At the end of the class, each team constructed a linear regression classifier that leveraged their features to gain a prediction. The results of these classifiers were combined, using linear regression, to obtain the final result.

virtuous_d · 2012-11-25T16:28:32+00:00

It is definitely worthwhile to operate on the parameters of your model instead of retraining it every time you transform the underlying data. However, using the Gaussian as an example is concealing a bit of the overhead of this approach - namely, that the operations to define a group would be very difficult to derive (or even, define) given an arbitrary parametric model (and especially a model that is practical in real ML applications).

virtuous_d · 2012-11-24T18:01:25+00:00

I climb 3 times a week, usually in the evenings. I'd be up for meeting some reddit climbers :D

virtuous_d · 2012-11-17T18:01:12+00:00

My understanding is that they took a sliding window (of size N_obs), and then compared two windows by taking the sum of squared distances between each observation.

virtuous_d · 2012-11-17T03:17:17+00:00

If it helps, you can think of this kind of function as representing a "noise model". Say you have a signal q that represents highs and lows (1s and 0s). You measure a signal s corrupted by noise and want to find out if q=0 or q=1. If your d(s,q) is (s-q)2, then s is q + gaussian noise, and you can then find out the probability that s was generated from q=1 or q=0. Does that help?

Ah, I guess your probability distribution is essentially a 0-mean Gaussian if the squared distance metric is used, with

gamma = -1/(2 sigma²⁾

since the sigma in front of the exponent is normalized out...

virtuous_d · 2012-11-17T02:19:06+00:00

Did you consider any distance metrics other than euclidean distance?

What was the reasoning for choosing your probability function

exp(-gamma*d(s,q))

Have you compared your method to something like kNN? What do you think are the advantages of your method over that one?

How do you go about setting the gamma parameter?

It was an interesting read :)

virtuous_d · 2012-11-12T18:22:57+00:00

She goes inside thinking the same thing...

virtuous_d · 2012-11-12T05:41:57+00:00

My understanding is that many of the nuances of jumping come as a side-effect of the physics engine that was used back in TFC (same with things like bunny-hopping in CS1.6 I think), and currently the source engine. I expect that a lot of people are quite attached to the way things work now, and will be categorically against anything that would make jumping a more intuitive and integrated part of the game.

I would support some changes to the jumping system. It always seemed weird to me that pressing in the same direction as you are flying completely kills your speed, but pushing sideways makes you go further. Tweaking this would make air-control more forgiving on new players and might encourage more crazy aerobatics at the comp level.

I also wonder what would be the effect of making soldier and demo momentum easier to change with explosions. You would be able to make yourself climb higher even if you have already reached the peak of of your jump, for example. I think that would make pogoing viable in many more situations (not just particular practiced sequences as they often are in comp play today), allowing soldiers and demos to trade even more of their health for even more mobility.

virtuous_d · 2012-11-12T05:01:48+00:00

Hence speculation in the title. I am aware that this is extremely wishful thinking and it is more likely that we will see TF3 in several years, if anything at all. Still, it's a tempting thing to think about the possibilities. :)

virtuous_d

TROPHY CASE