tba's comments

tba | 12 years ago | on: Using neural nets to recognize handwritten digits

This is a cool exercise! After completing it, I wanted to find out exactly what each NN hidden node represented. I trained a tiny (10 hidden node) NN on an OCR dataset and created a visualization here: https://rawgithub.com/tashmore/nn-visualizer/master/nn_visua... .

Can anyone figure out what each hidden node represents?

You can also select a node and press "A" (Gradient Ascent). This will change the input in a way that increases the selected node's value. By selecting an output node and mashing "A", you can run the NN in reverse, causing it to "hallucinate" a digit.

tba | 14 years ago | on: Apple responds to NYT: "We're among top payers of U.S. income tax"

> Social Security is not in trouble

This is a fringe viewpoint at best. With our current policies, the Congressional Budget Office predicts SS will become completely insolvent between 2036 and 2038 (p. 54 of http://cbo.gov/sites/default/files/cbofiles/attachments/06-2...). The "easy" fix will require significant payroll tax increases, which seems politically unlikely considering we just REDUCED the FICA tax by 2%.

tba | 14 years ago | on: Deconstructing "K&R C"

I'm confused. What is the "defect" in K&R's "copy(char to[], char from[])" function?

The author notes that "the second this function is called...without a trailing '\0' character, then you'll hit difficult to debug errors", but no function with that signature could possibly work in this case.

The built-in "strcpy" function has the exact same limitation. Does the author have a problem with it as well? Null-termination is a fundamental concept of C strings; there's no reason to shield C students from it.

The other example of "bugs and bad style" in this "destruction" of K&R C is a minor complaint about not using an optional set of braces.

I hope the remainder of the [incomplete] chapter demonstrates some actual bugs in the book's code, because it currently doesn't live up to the first paragraph's bluster.

tba | 14 years ago | on: Deconstructing "K&R C"

No? It ensures that malloc didn't return a NULL pointer and the '&& "memory error"' is a common pattern to add a comment describing why an assert() statement failed.

tba | 14 years ago | on: Grade inflation: why weren’t the instructors all giving all A’s already?

"I'd round up rather than down...The end result was a grade distribution that was just slightly more generous than the last time. And hence I perpetuated the cycle."

Next time, why not begin with a slightly harsher grade distribution? Then selective rounding up would result in the same distribution as the previous year.

tba | 14 years ago | on: Are teachers underpaid? It depends.

It's not hard to believe that the average teacher is paid about what they're worth.

The more important question is whether the pay is competitive to attract teachers of sufficient quality.

tba | 15 years ago | on: Arguing for Immortality

Is your claim that mortality is indistinguishable from immortality? Here is a simple counterexample:

An immortal can count (by ones, out loud) from 1 to a googol. A mortal cannot.

tba | 15 years ago | on: Bitcoin hits US$ 4, after being mentioned on CNN yesterday

"think of the bounties on someone like Kim Jong-Il"

Did you ever think of the bounties on anyone inconvenient to governments or big businesses? The founders of The Pirate Bay, Julian Assange and Bradley Manning, BP whistleblowers, environmental activists and climate scientists – would society be better off with them all dead?

tba | 15 years ago | on: How I got sued by Facebook (2010)

Great article. Is this the same person that Palantir mentioned as a potential source of Facebook information for social engineering attacks?

From the leaked HBGary emails:

"The Palantir employee noted that a researcher had used similar tools to violate Facebook's acceptable use policy on data scraping, 'resulting in a lawsuit when he crawled most of Facebook's social graph to build some statistics. I'd be worried about doing the same. (I'd ask him for his Facebook data—he's a fan of Palantir—but he's already deleted it.)'"

http://arstechnica.com/tech-policy/news/2011/02/black-ops-ho...

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