jeffcoat · HackerTrans

jeffcoat

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How I Teach When I Really Want My Students to Learn

econlog.econlib.org

2 pointsby jeffcoat12 yıl önce0 comments

Radiation Dosage Visualization

blog.xkcd.com

18 pointsby jeffcoat15 yıl önce2 comments

A Bayesian Classifier for Wine

slate.com

10 pointsby jeffcoat15 yıl önce0 comments

Marketing insights from an infomercial consultant

itreallyworks.tv

24 pointsby jeffcoat17 yıl önce6 comments

"Almost Everything I've Learned about Direct Response Television"

itreallyworks.tv

1 pointsby jeffcoat17 yıl önce-1 comments

comments

3 ay öncediscuss

We can only guess about what's going wrong for you specifically . But I like guessing:

(extremely mild spoilers:)

- A core skill for Nethack is understanding how much danger you're in at any particular moment. Your comment about soldier ants below tells me you've made good progress here. But you need to recognize when you're in danger and how long you have to deal with that problem before you'll react appropriately.

- Nethack's dungeon isn't linear, it branches. (Think of the gnomish mines here, but there are other examples deeper.) When you're getting in over your head in one branch, go back up the stairs and switch to another one.

- When you're in immediate danger, Stop. Look through your inventory, consider your options. Think especially about wands, think about ways to write Elbereth, think about scrolls. Think about ways to use diagonal movement to your advantage to get to an escape, or a more defensible position. You have all the time in the world to think. There may not be a solution, but I've died more than a few times with more than one thing in my inventory that could have saved me.

- You need to be able to identify some things without waiting for a scroll of identify to fall into your lap. Price is the easiest way to identify the scroll of identify itself. It's also straightforward to learn to identify most useful wands: with spoilers or by experimenting. Engraving with the wand will often give you more information than zapping it. A lot of your early I'm In Danger toolkit will come from wands you've identified this way.

Good luck, have fun.

(Intermediate player, a few dozen ascensions 20 years ago.)

2 yıl öncediscuss

Even switching from magnetic to true is unhelpful close enough to the South pole. All directions are north.

We have to switch to "grid" north to make sense of directions there.

https://en.wikipedia.org/wiki/Universal_polar_stereographic_...

4 yıl öncediscuss

This is amazing. Thank you.

6 yıl öncediscuss

Probably not. Knowing the speed-of-light round trip time to a network location gives you a bound on how much you can improve the performance of remote operations.

For example, I'm in Austin, querying a database hosted in Amazon's us-east-1 data center ("Northern Virginia"). Call it 1000 miles away, 2000 mile round trip.

    You have: 2000 miles
    You want: millilightseconds
            2000 miles = 10.736388 millilightseconds

If I have a query that's taking < 1ms, no optimization of how that query is executed by the database can possibly improve the overall performance.

6 yıl öncediscuss

  MCMLXVII + LXV
   = MCCCCCCCCCLXVII + LXV (canonicalize)
   = MCCCCCCCCCLXVIILXV    (concatenate)
   = MCCCCCCCCCLLXXVVII    (sort)
   = MCCCCCCCCCLLXXXII     (combine, VV => X)
   = MCCCCCCCCCCXXXII      (... keep combining, LL => C)
   = MMXXXII               (... C{10} => M, nothing left to combine)
   = MMXXXII               (optionally, look for ways to re-write with the subtraction rule)

9 yıl öncediscuss

I choose to believe it's a prophecy, foretelling the coming of a Universal search engine that will someday make that joke stop working.

10 yıl öncediscuss

You're right, thank you.

10 yıl öncediscuss

You're recalling a different incident: engine-out problems are a routine part of flight training at every level.

You're thinking of https://en.wikipedia.org/wiki/United_Airlines_Flight_232

where so much of the plane broke that they had to invent a new way to fly it.

I can't turn up a reference right now, but like you say, in the next few years that failure was repeatedly simulated, and all the simulated planes crashed.

(IIRC, Haynes declined to try his hand at any of the simulations, explaining that the one time when it really mattered was enough for him.)

10 yıl öncediscuss

Certified Programming with Dependent Types

http://adam.chlipala.net/cpdt/

10 yıl öncediscuss

You'll also need to know that e^x = sum{0 -> infinity} x^n / n!.

10 yıl öncediscuss

Not so stupid: Start with the phrase "Hoteling's rule" for a century of academic analysis of that question.

If you own an oil field, you have to balance a number of factors:

* How is the price of oil changing, relative to overall inflation? You mentioned this one.

But also,

* Are technological improvements (either increasing the total amount of extractable oil in the world, or outright oil replacements) going to dramatically lower the price if I wait too long?

* Is it still going to be my oil next year, or am I going to be first against the wall when the next revolution comes?

My (unsophisticated, outsider) opinion is that if you see oil-producing countries selling as quickly as they can, that's weak evidence that they're worried about the last two bullets.

10 yıl öncediscuss

I enjoyed it: not a sports fan, knew little of baseball except that the one game pro game I've seen in person was super-boring [to me].

_Moneyball_ isn't about baseball so much as it's about how easy it is for humans to be tricked by our intuitions and habits. Moneyball talks about baseball from the point of view of someone who everyone just assumed would be good -- and wasn't -- as he's trying to make more and more objective assessments of players, and wielding his conclusions against competing, more traditional managers.

10 yıl öncediscuss

It's because "latitude lines" aren't really lines in this context (except the one at the equator).

If you took two points from one of those latitude "lines", you'd always be able to find a shorter path between them than the path along the latitude. If you take the shortest path between the two points and extend it all the way around the sphere, you'll end up with a great circle. That great circle is an actual "line" in this geometry.

https://en.wikipedia.org/wiki/Spherical_geometry

11 yıl öncediscuss

It's obvious that moving oil in space helps, right? You move the resource from a place it's relatively plentiful to a different place where oil is relatively scarce. Say, from the Persian Gulf to Australia.

The same thing is happening here:

These ships are trying to move oil from a time when oil is relatively plentiful to a time when it's relatively scarce. It's riskier, but if they succeed, everybody wins: they make money, and they do it by lessening that future scarcity.

11 yıl öncediscuss

All of this is fine for real-valued inputs and outcomes. It's the number of events (coin flips, measurements, etc) that we're restricting to be countable.

11 yıl öncediscuss

I think I know what you're getting at, but the problem here is that prosecutors have some discretion.

The chain of thought that goes

  I only prosecute worthy cases

  => I picked those cases because these people are guilty,
      and need to be convicted for the good of society 

  => my conviction rate is exactly the same as my 
     'I made a better world' rate.

must be very tempting. Wrong, but tempting.

11 yıl öncediscuss

ABC ran pretty much this same story in 2010:

http://abcnews.go.com/Blotter/loaded-gun-slips-past-tsa-scre...

  According to one report, undercover TSA agents
  testing security at a Newark airport terminal on
  one day in 2006 found that TSA screeners failed
  to detect concealed bombs and guns 20 out of 22 times.

  A 2007 government audit leaked to USA Today revealed
  that undercover agents were successful slipping simulated
  explosives and bomb parts through Los Angeles's LAX
  airport in 50 out of 70 attempts, and at Chicago's
  O'Hare airport agents made 75 attempts and succeeded
  in getting through undetected 45 times.

11 yıl öncediscuss

The slides are interesting enough that I went looking to see if the actual talk that goes with them was online anywhere; found it at

http://chariotsolutions.com/screencast/philly-ete-2015-7-mon...

12 yıl öncediscuss

It's tough being smart and influential: your [Dijkstra's] successes and mistakes end up going through the same megaphone.

12 yıl öncediscuss

I was in a 1 or 2-person office while I was at IBM. Their policy (at that branch) was a private office for senior developers and up, two to an office otherwise.

I'm at Motive right now; the large majority of developers here have their own office. (And we're hiring: developers and testers, no telecom experience necessary, mostly in Austin, TX.)