skysight-inc/HackerNews huggingface dataset:
Ask HN: Good 15-20 min. CS challenge for high school students?
I am helping design a CS-related activity for a Let's Talk Science competition (http://www.letstalkscience.ca), which promotes STEM amongst high school students. In the competition, teams of six students will move from station to station, trying to complete each as quickly as possible.

One station might give the team a metre stick, then ask them to measure the height of a building. (This can be solved by using similar triangles to estimate the building's height.) Time penalties are added to the team's completion time depending on how close their answer was.

My constraints are thus:

* Most students won't have CS/programming knowledge
* Challenge should not require a computer
* Idea should challenge teams of six students for 15-20 minutes
* Challenge must have clear answer that can be objectively scored (not judged)

One reasonably good challenge presents a sentence encoded with a Caesar cipher, then asks the students to decode it. The person running the station give a short explanation of what a Caesar cipher is, then leave the teams to decode the text. Time penalties are awarded based on correctness -- each incorrect character adds a 30-second penalty.

The Caesar cipher idea has been used often in the past, however, and I'm trying to develop something novel. I have been through the various activities on CS Unplugged (http://csunplugged.org/activities), but none appealed to me -- the exercises I saw were generally aimed at illustration and not suitable for competition, were too simple, or required too much explanation of background knowledge.

Do you have any ideas on what would make a fun CS-related challenge for teams of six high school students?

Thanks!
Removing the Magic From Regular Expressions
What practice of Hachette is amazon objecting to? The article doesn't specify the cause of the conflict.
> When you're lying on your death bed, and you look back; will you be proud that you spent all that time

This is exactly the explanation I use when people ask me why I quit my high-paying but soul-sucking job, and now working for nothing (on my savings as long as it lasts) on a non-profit idea, and am looking for a job that does real good in this world and feeds my soul even if it pays peanuts.
There is an interesting comment below the article:
"Yuhong BaoMay 23, 2014 at 10:14 AM

On this matter, anyone remember the Netscape random number generator bug:
http://www.cs.berkeley.edu/~daw/papers/ddj-netscape.html
Notice the paragraph at the end about RSA Data Security!"
I love this invention. Imagine put one in your back yard and the next time you are holding a party, you can take out your beer like a magic.

But I think compared with the CO2 that comes out from your beer, the CO2 release reduced by saving electricity isn't that much...
> but I'm not clear why Amazon is obligated to sell a publisher's books, much less at the publisher's desired prices.

No one has said that they are. Likewise, the affected publisher, and the news media, are not obligated to fail to inform the public of Amazon's tactics so that they are aware that Amazon having smaller-than-usual discounts, "not available" notices, and long shipping times may well be a sign not of any issue with the availability of the book, but of Amazon's disputes with the publisher, and that therefore if they are encountered when looking for a particular book, a consumer would be well advised to look at other online retailers, who, while their usual discounts may be lower, may have better discounts for the book at issue or have it available when Amazon says its unavailable, or have it with a more reasonable shipping time when Amazon does not.

Amazon is essentially leveraging the trust that consumers have in them as presenting a seemingly comprehensive catalog and best terms in the online book retailing business to selectively pressure publishers, and its completely fair to inform consumers that, in the particular case of these kinds of disputes, that trust may, however well earned it was previously, not be warranted -- and what the particular symptoms are that such a dispute is affecting the book you are looking for.
I'm inclined to agree with this comment. Saying "The IRS wants all my after-tax income" is a very different statement from "The IRS gave me a payment plan that allows me to pay an expensive rent and basic living expenses while also paying off my debt in five years". Living frugally and paying down debt might be uncomfortable, but it's not unusual and is fairly well understood. If you can move to a different area, you can allot more money for your living expenses.
Yes you are right. That is decidedly
inconvenient to maintaining credibility on this thread but in the interests of being transparent you are right.

It was early in my HN posting and it was a stupid title. Not even remotely close to the original Reddit title.

I concede the point. If I am shill I must be a pretty poor one to torpedo my own credibility like that.

shrug
Exactly. The ground is usually 58F. I remember reading about this in a thermal home book. (If you effectively bury 3/4 of your house, you only ever have to warm it to 70F from 58F.)

It's actually somewhat funny. Did they think there were ice cubes under the grass when the designed this?
Please respect factual arguments instead of tolerating stock downvotes. Good arguments aren't like that, assuming good conversations are the goal.
In the 10th paragraph: "Amazon, which is under immense pressure from Wall Street to improve its profit margins, is trying to get better terms on e-books out of Hachette,"

Amazon also previously used this playbook with MacMillan Publishing.
Can the Nervous System Be Hacked?
It would be nice if Congress had a concept of a "code freeze".

This quote as also odd:

> “While far from perfect, this bill is an unambiguous statement of congressional intent to rein in the out-of-control NSA," said Laura W. Murphy, director of the American Civil Liberties Union's Washington legislative office.

A statement of congressional intent sounds like asking someone nicely.
Rodrigo de Jerez, the first European smoker and his deal with the devil
Yup. I'm in the final editing stages for Rails 4 in Action, and then I'm hitting that hard. My time at Balanced has certainly given me a lot of good examples for it.
Related: https://usergrid.incubator.apache.org/
It seems strange to me that they would be re-purposing video tape for digital audio, given that digital tape technology was used in computers since UNIVAC in the 1950's [1].

[1] http://en.wikipedia.org/wiki/Tape_storage
DarwinTunes relaunches {game using selection to "evolve" music}
Leaving aside my pet peeve of people using "begs the question" inappropriately, your question is answered by the article.

An optimum colony of bacteria is hard to maintain and propagate outside the optimum environment--namely, on your skin. The colony also reacts negatively to being disinfected. The experiment is to establish such a microbiome and then leave it the hell alone.
Probably not such a problem in Denmark...
This is the previous scandal one would think Cornell and Musk are both well aware of:

https://en.wikipedia.org/wiki/Darleen_Druyun
Listen to the Crack
@indie303 on Twitter. If he won't do it, he can point you to good outfits that will.

"Reputable" is a loaded term in the infosec world. There are a lot of "reputable" incompetents.
Oh boy, so I get to be the contrarian again.

First of all, isn't it a bit dramatic to say "your entire being opposes" your task? It's not like you're out committing genocide or something. You're programming, and you have to work on a crappy programming task. Every programmer who ever worked a professional job has had to do this at some point. If the very fiber of your soul is wrapped up in your employer's MegaAccounting Client V3.0 REST API, I'd recommend re-thinking your emotional attachment to your job.

That money you get every two weeks is called "compensation" because it is compensating you for your time, which you would probably otherwise spend doing something more pleasant. This is the realistic world of grown-up work life.

If your company's Marketing bone-head says the customers want a green oval button instead of a system-standard button, well, it's stupid, but I'd laugh at how much they're paying to get this ridiculous code written and just write the damn code. It's really not worth losing sleep or sanity over. Not being emotionally attached to your work allows you to shrug off the stupid stuff that Really Doesn't Matter.
There is a statute of limitations for the IRS to audit you on a properly filed return (3-6 years, depending on the specific return). However, there is no statute of limitations for imposing back taxes/penalties/interest on income that was never reported.

In some circumstances, this can even include later years in which a return was filed, if the unreported income affected the income, deductions, credits, losses, or other tax items in that later year. This is usually not an issue for individuals, as the problem usually arises from carried-over losses or credits that are generally available only to corporate entities.
Yeah, no worries man.
> What practice of Hachette is amazon objecting to?

Amazon isn't publicly objecting to any Hachette practice. Per the earlier article on the dispute linked from the source article, [1] Amazon is seeking more favorable contract terms with Hachette (and neither side seems to be disclosing what particular terms are at issue), and is working to discourage sales of their books -- and promote alternatives to people specifically seaching for Hachette books -- to force Hachette to agree to Amazon's preferred terms.

[1] The earlier article: http://www.nytimes.com/2014/05/10/technology/writers-feel-an...
Where there are no thieves?
In some parts it looks like I imagine the USA. I live in Germany now and the malls in Poland still stun me. It's unbelivable how fast those malls and french hyper-markets came out of nothing.

I still don't understand how they survive. There've been 3 malls within few kilometers on the same road in Slupsk.
Wait, why are you using your own Auth Key and asking the user to provide email/password?
See also: cellar.
Amazing how a little fun garden gadget can evoke such repugnance.
https://hn.algolia.com/?q=http%3A%2F%2Fjeff-vogel.blogspot.d...
Just first ask yourself if the next person to work on this code will appreciate the 'new features' you used.
Are you sure it shouldn't be 2^(3 + 3 + 3*12) = 2^42 ? That would still be a pretty big number, but not yet astronomical.
So the House Committee on Rules committee butchered this bill to the point where it actively went against the legislative intent. In case anyone is curious, here's the current members of the House Committee on Rules:

- Pete Sessions, Texas, Chairman (R)

- Virginia Foxx, North Carolina Vice Chair (R)

- Rob Bishop, Utah (R)

- Tom Cole, Oklahoma (R)

- Rob Woodall, Georgia (R)

- Rich Nugent, Florida (R)

- Daniel Webster, Florida (R)

- Ileana Ros-Lehtinen, Florida (R)

- Michael C. Burgess, Texas (R)

- Louise Slaughter, New York, Ranking Member (D)

- James P. McGovern, Massachusetts (D)

- Alcee Hastings, Florida (D)

- Jared Polis, Colorado (D)
In Buenos Aires I've only seen one guy riding unicycle. He seemed to be commuting to work: he was very, very fast and always blazing through the street at the same time.

Is it comfortable for short commutes?
> The only reason a bacteria will be less prone to washing away is if its useful for our skin in some way and has a symbiotic relationship with it.

Why do you think that ability to produce glue that's resistant to soapy water might only come from some form of symbiosis with the host?

> In any case, is there any evidence that we do have some skin microbiota that sticks even after good soap wash?

Do you think soap producers wouldn't claim that their soap removes 100% of bacteria instead of 99,99% if it wasn't provably false?

And what do you mean by good soap wash? Do you know how surgeons wash their hands? And yet they still cover those thoroughly washed hands with sterile gloves.

Infection rates double if there is a hole in a glove despite the thorough washing. I think you may consider it to be evidence.

http://www.quora.com/Surgery/Why-do-surgeons-wash-their-hand...
I think this reveals Amazon's key weakness -- they don't make any money.

Amazon's big cachet was always "Earth's biggest selection". If they are going to behave like cable companies and refuse to sell books from major customers, they are really failing their customers.

If I want to buy a book, I shouldn't need to know or care about who publishes it, and whether or not they are in a pissing match with Amazon. The first time I run into that situation will be the last time I use Amazon.
> untouchable" 12 years ago, it would be even more so today in 2011.

You might also say that there are many more naive users today, and that bad designers have been breKin the back button a lot more often, which means that fewer people know what should happen and people have less expectation that what should happen is what's going to happen.
The CO2 in the beer is not of fossil origin, so it's not a relevant comparison.
Given that I don't choose a bigger fridge specifically to store beer in, and I tend to have, say, 4-8 bottles of beer in the fridge at any one time, and I wouldn't store anything else in the fridge to replace it, and a fridge becomes less efficient the emptier it gets ... is this really a good idea?
How to be a self-supporting anthropologist
No, everyone has plenty of beer in Denmark! ;-P
I think the reason you are getting downvoted (I upvoted) is because you are making statements like this:

"buying is almost always better"

"This nyt analysis isnt correct"

I think the point of what you are saying simply is if you find the correct set of circumstances in terms of the rent you are able to get for the house as well as the market conditions, cost, interest etc. it makes sense to find a renter (taking a whole host of other specifics into account as well) and, assuming housing continues to increase in price it's a strategy to have an asset many years later (could be 15 to 25) that you have no mortgage on and you are collecting rent.

This is a pattern that I have seen many people do and, once again, given the specifics of what you are buying (and when) is something that seems to make sense in many cases.

Oh, one other important thing that I don't feel people are taking into account.

When you use your strategy you also have a form of forced savings because your money is tied up. So when you wake up 20 years later with a paid off asset you have that asset and haven't spent the money on other things.

Here is another example of forced savings.

You own a business and that business has a value at the end of 10 or 20 years and you can sell it. Vs. you are a consultant and have no asset value to your business but make more money than the business owner does.

The consultant could of course take a part of his earned income every year and sock it away. But many if not most people aren't disciplined enough to do that. So making less and building an asset is a form of forced savings.

People can do all the math they want to justify any decision of course but taking psychology into account and people's spending habits (given money in their bank account) is also important as well.
P.S. I'm not saying it's not cool, just that I don't particularly see an eco-benefit.
Tape is tape, and VHS was a popular platform. I do remember people wanting "higher grade" Super VHS for some digital audio recording platforms, but for the most part you could even use regular VHS in a pinch.
I'm really enthusiastic about Keybase and am hopeful that it will succeed where others have failed to push mainstream adoption of PGP.

I've been trying to think of innovative applications of the Keybase API [1], which exposes much (most?) of the functionality available via the command line client.

I've got a few vague projects in mind but would love to hear more ideas. I've got a few Keybase invites left and will give them while they last to anyone who proposes an interesting use of the API, as long as Keybase doesn't object to this type of "contest" [2].

1. https://keybase.io/docs/api/1.0

2. maxtaco and malgorithms, please let me know if that's an inappropriate use of the invites and I'll rescind the offer.
What problems did you run into while using RequireJS?
Start them all at 0, and only invoke the scaling rule once the total is over 100%?
Yes. Apparently 15-20 years is enough for people to forget and and make a full circle in search of less sucky thing.
Who says your job can't be something you enjoy? What if programming is what you'd be doing if you weren't at work? I know that's certainly the case for a lot of programmers I know.
Well, he has a point - the Nordic countries are known for vastly lower rates of criminal behaviour and for their civilized treatment of those who do end up in prison. One might say that the risk of being attacked/robbed/stolen from is considerably lower than e.g. in Germany, the UK, or the US.
Yes. SSL 3.0 is okay, but not 2.0.
Bay Area: What do you use for broadband internet?
I am on comcast and it sucks... the connection if very flaky and often slow... please help me find an alternative...can't wait until google fiber comes.
This is a good advice for people who are temporarily in a bad mood.

However, it is the totally wrong way to fight an upcoming burnout.
Hm... Usually we think nordic countries are close to paradise.
But looking at this I might be wrong. Except for murders the crime rate seems to be above US levels.
http://www.nationmaster.com/country-info/compare/Denmark/Uni...
Edit: Some of the stats on that site seem to be contradictory, though. So, whatever, I think I need a cold beer now.
https://web.archive.org/web/20140103233938/http://www.inf.et... (ETH removed the website recently)

given that ETH is on Tango and that page also mentions SuiteSparse (also used for Google autonomous cars), it could be the case that Tango is based on Structure from Motion.

http://www.cise.ufl.edu/research/sparse/SuiteSparse/

another related page is still up: http://www.inf.ethz.ch/personal/acohen/papers/symmetryBA.php
The difference is that under the English rule there's a presumption that the loser pays the winner's legal costs, while under the American rule the presumption is that each side bears their own costs. In a few areas of law, Congress has by statute adopted the English rule, and in those areas it is common for courts to insist on posting a bond, but in places where the American rule is in place it is very uncommon to do so.
Let's say you're looking to buy a lawn chair on Google.

Without DKI: You search "Lawn Chair" and see a list of ads with headlines like "Target", "The Patio Store" and "Summer Furniture".

With DKI: You search "Lawn Chair" and the first thing on the page is "Cheap Lawn Chairs".

This is better for you as it's immediately clear where to click to find the thing you were looking for. DKI allows small advertisers, who have neither the time nor capability to manage hundreds of ads, the ability to still present an ad that is tailored to your search when they offer what you're looking for.

The ad still has to actually link to the lawn chairs you wanted. If it doesn't, that keyword would be rejected by the AdWords editorial team in the advertiser's campaign for that landing page. Even if it made it through review, it'd suffer algorithmically compared to ads that do link to lawn chairs; the bounce rate and poor landing page relevance scores would drop the ad's Quality Score, which means ads that do link to lawn chairs will rank above it, or the ad won't be displayed at all no matter what the store is willing to pay per click.
I see, but most mortgage doesn't have interest income tax deduction here in Canada?

edit: Just check interweb, only mortgage that being used to invest for more incomes are eligible for tax reduction in Canada, thus more trouble to convert a house mortgage to investment mortgage.
> Did they think there were ice cubes under the grass when the designed this?

Permafrost does exist, albeit not at Denmarks latitudes.
This post is quite vague on the details, but I came across a a more detailed paper recently that also promised big gains:

http://www.ece.eng.wayne.edu/~sjiang/pubs/papers/ouyang14-SD...

SDF: Software-Deﬁned Flash for Web-Scale Internet Storage Systems

Working with/as Baidu, they are using an FPGA as a custom flash controller that exposes the underlying "channels" more directly.
Complacency, Subservience and all that Bullshit
How My VP of Sales Doubled Our Sales in 90 Days. And No, It Wasn’t Magic
Stock Footage | royalty free stock video for video producers
So because to you in the US PHP is dead and dying (for which I'd really like to see some hard evidence) someone in Nigeria should use RoR?

You're not doing RoR a favor here. If that's the best argument that can be brought to bear. I'd know a few that are a lot stronger than that and I would not have to resort to unsupported stuff.

http://langpop.com/

Has PHP to be about twice as popular as Ruby, and the 3rd most popular language (after C and Java, of which I would consider Java to be a viable alternative and C not really).

http://www.tiobe.com/index.php/content/paperinfo/tpci/index....

Has them at PHP 3.3 and Ruby 1.2% respectively.

Dead and dying indeed.
Probably e-book pricing. Hachette doesn't really have any reason to come out publicly and says they are trying to keep e-book prices high, since while that is good for authors and Hachette, it's bad for the consumer pocketbook.
> So it is a thing then?

I've not heard of it happening to anyone in recent years, but Network Solutions were definitely accused of it in 2009, using the 5-day "tasting" period. See http://en.wikipedia.org/wiki/Domain_tasting#Anti-Domain_Tast... for a mention. I would very be surprised to find that it doesn't go on in various places to this day, so for paranoia's sake only search for names you want using known reputable providers.

Way back in is mists of time (~1999/2000, while at University) I had it done to me. We were going to register a name for our student house (and a few other people) and searched for two options both of which were available at the time. A week later when we came back both were registered by the same individual (not directly linked to the company from what we could gather) with a "buy this domain! (for several times the usual cost)" page present. This could have been a coincidence of course, so we looked up a collection of other convincingly real names (from various locations so it wasn't a block of lookups from the same address). A short while later they were all registered the same way, and not on the "5 day" thing either because they all still were a while later. We could have been cruel and search a great many more (had we actually cared about the name(s) we "lost" we might have done) to waste their money but didn't as we had far more important and/or fun things to be getting on with at the time.
That's a vulgar way of demonstrating Amazon's muscle power.
I have one nearby, and it's great!
(I can't do more than a few seconds without falling over though)
SDF: Software-Deﬁned Flash for Web-Scale Internet Storage Systems
I must say, there was a bit of a learning curve to Browserify. Now that I have it working I feel it's one of the best tools we have for front-end development.

I auditioned Component and RequireJS but both of those felt like a kludge. Browserify lets you do node style includes as well as compile your JS into separate bundles.

I wrote a very small structure and build system [1] for our front-end projects at work that uses Browserify / Gulp and can compile everything into separate modules. It uses nginx/apache for routing and since it's all HTML/CSS and compiled JS, it's lightning fast to deliver.

I think this guide is fantastic; we just need more things like this to lower the barrier to entry.

[1] https://github.com/TeachBoost/mishra