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aesthesia's comments

aesthesia | 3 years ago | on: The Secretary Problem

Interestingly, the traditional algorithmic solution is inherently asymmetric: it gives better outcomes to one gender than the other.

aesthesia | 3 years ago | on: The Secretary Problem

Crucially, the optimal solution depends on the specific constraints. So you can’t just take a solution derived under one set of assumptions and use it in another situation without losing whatever guarantees it made in the original case.

aesthesia | 3 years ago | on: No Refrigerant Left Behind

> So long as we are burning natural gas for energy, it's better to use it directly in your home, vs have someone else burn it, make electricity, then use that.

Only if you're using resistive heating. Heat pumps run on natural-gas-produced electricity can be at least as efficient as direct natural gas combustion for heating, and they automatically transition to cleaner sources of energy as the grid does.

> you would have to use reusable ones hundreds of times, and never wash them - ever, for them to be better

I understand that this is the case for cotton bags, IIRC due to high water use in cotton production, but for other types of reusable bags the threshold is lower.

> people reuse around half of them for garbage bags

This estimate seems like it's significantly too high. I do most of my grocery shopping at places that don't provide free plastic bags, and yet I still end up with far more single-use plastic bags than I could ever use for garbage. I would guess that no more than 10% of single-use bags actually get reused for trash.

aesthesia | 4 years ago | on: Graph Theory and Linear Algebra [pdf]

I don't think that follows. Since the adjacency matrix contains O(n^2) _bits_ of information, the number of adjacency matrices of graphs is O(2^(n^2)). This makes sense: graphs with vertex labels {1,...,n} are in bijection with symmetric n x n binary matrices with zero diagonal. It's difficult to quantify how much information is lost when we reduce this matrix to its spectrum, since the eigenvalues are real numbers, but there are O(n) degrees of freedom, and in principle plenty of room to distinguish any two graphs.

Of course, as a sibling comment notes, unlabeled graphs are often more interesting, for which one has to look at equivalence classes of adjacency matrices. The spectrum is nice here because it is automatically invariant to vertex permutations and hence a graph isomorphism invariant. The existence of nonisomorphic cospectral graphs is not immediately obvious, although there are simple examples, and that there are infinite families of cospectral pairs is even less obvious. So at the very least, it's interesting that the spectrum is not a complete invariant, and that it does work well for certain classes of graphs.

aesthesia | 4 years ago | on: Swiss back further restrictions on tobacco advertising

Yes, you should drink when you’re thirsty, and forcing yourself to drink some arbitrary quantity of water every day is probably pointless. But water without any dissolved minerals is also bad for you, and many bottled brands add other salts (eg calcium chloride) to filtered water for flavor. I’ve also never experienced the phenomenon you describe where water with sodium fluoride fails to satisfy my thirst. While I certainly prefer the flavor of filtered water, drinking tap water doesn’t make me crave any other drink. Has there been any research done on this topic?

aesthesia | 4 years ago | on: What kind of Apple Mac did Arthur Dent have?

Not quite: at one point there's a reference to a non-wizard character having a PlayStation, which I found kind of jarring to read at the time, precisely because it pinned the story down to a very particular point in time.

aesthesia | 4 years ago | on: Theses on Sleep

Connect an LED directly to a battery (as in many cheap flashlights) and there will be no flicker.

aesthesia | 4 years ago | on: Can a biologist fix a radio?–Or, what I learned while studying apoptosis (2002) [pdf]

This paper inspired another fun followup: "Could a Neuroscientist Understand a Microprocessor?" [0] The authors investigated a 6502 running Atari games using popular neuroscience methods, finding things like transistors that are uniquely necessary to run Space Invaders, but, of course, never getting close to an actual understanding of how the processor functions. It really highlights how even with the huge amounts of data we are able to get from biological systems now, there's still a lot of information we paradigmatically can't understand.

[0]: https://journals.plos.org/ploscompbiol/article?id=10.1371/jo...

aesthesia | 4 years ago | on: The Spacing Effect

I found this article [0] by a teacher who experimented with using formal spaced repetition systems in a classroom insightful. There were clear differences between motivated and unmotivated students, as you note. He ultimately decided that its utility was narrow, and that keeping students from forgetting facts is not the most important part of education.

[0] https://www.lesswrong.com/posts/F6ZTtBXn2cFLmWPdM/seven-year...

aesthesia | 4 years ago | on: You block ads in your browser, why not in your city?

> they prototyped roadside billboards thay could infer what radio stations the cars driving by were listening to

Any idea how this was supposed to work? I don't know how that information would leak out unless it was just listening for the audio from a car with windows rolled down.

aesthesia | 4 years ago | on: The Fourier transform is a neural network

As far as I can tell, you're still using a fixed inverse DFT as the reconstruction layer, so it's not just rediscovering the DFT on its own. Instead of learning a linear transformation from input-output pairs, it's learning the inverse of a linear transformation when that transformation is given as an oracle. It's not terribly surprising that this works, although there are probably some interesting issues of numerical conditioning in the general case.
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